CSV_XS(3) User Contributed Perl Documentation CSV_XS(3)NAME
Text::CSV_XS - comma-separated values manipulation routines
SYNOPSIS
# Functional interface
use Text::CSV_XS qw( csv );
# Read whole file in memory as array of arrays
my $aoa = csv (in => "data.csv");
# Write array of arrays as csv file
csv (in => $aoa, out => "file.csv", sep_char=> ";");
# Object interface
use Text::CSV_XS;
my @rows;
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
open my $fh, "<:encoding(utf8)", "test.csv" or die "test.csv: $!";
while (my $row = $csv->getline ($fh)) {
$row->[2] =~ m/pattern/ or next; # 3rd field should match
push @rows, $row;
}
close $fh;
$csv->eol ("\r\n");
open $fh, ">:encoding(utf8)", "new.csv" or die "new.csv: $!";
$csv->print ($fh, $_) for @rows;
close $fh or die "new.csv: $!";
DESCRIPTION
Text::CSV_XS provides facilities for the composition and decomposition
of comma-separated values. An instance of the Text::CSV_XS class will
combine fields into a CSV string and parse a CSV string into fields.
The module accepts either strings or files as input and support the use
of user-specified characters for delimiters, separators, and escapes.
Embedded newlines
Important Note: The default behavior is to accept only ASCII characters
in the range from 0x20 (space) to 0x7E (tilde). This means that fields
can not contain newlines. If your data contains newlines embedded in
fields, or characters above 0x7e (tilde), or binary data, you must set
"binary => 1" in the call to "new". To cover the widest range of
parsing options, you will always want to set binary.
But you still have the problem that you have to pass a correct line to
the "parse" method, which is more complicated from the usual point of
usage:
my $csv = Text::CSV_XS->new ({ binary => 1, eol => $/ });
while (<>) { # WRONG!
$csv->parse ($_);
my @fields = $csv->fields ();
will break, as the while might read broken lines, as that does not care
about the quoting. If you need to support embedded newlines, the way to
go is to not pass "eol" in the parser (it accepts "\n", "\r", and
"\r\n" by default) and then
my $csv = Text::CSV_XS->new ({ binary => 1 });
open my $io, "<", $file or die "$file: $!";
while (my $row = $csv->getline ($io)) {
my @fields = @$row;
The old(er) way of using global file handles is still supported
while (my $row = $csv->getline (*ARGV)) {
Unicode
Unicode is only tested to work with perl-5.8.2 and up.
On parsing (both for "getline" and "parse"), if the source is marked
being UTF8, then all fields that are marked binary will also be marked
UTF8.
For complete control over encoding, please use Text::CSV::Encoded:
use Text::CSV::Encoded;
my $csv = Text::CSV::Encoded->new ({
encoding_in => "iso-8859-1", # the encoding comes into Perl
encoding_out => "cp1252", # the encoding comes out of Perl
});
$csv = Text::CSV::Encoded->new ({ encoding => "utf8" });
# combine () and print () accept *literally* utf8 encoded data
# parse () and getline () return *literally* utf8 encoded data
$csv = Text::CSV::Encoded->new ({ encoding => undef }); # default
# combine () and print () accept UTF8 marked data
# parse () and getline () return UTF8 marked data
On combining ("print" and "combine"), if any of the combining fields
was marked UTF8, the resulting string will be marked UTF8. Note however
that all fields before the first field that was marked UTF8 and
contained 8-bit characters that were not upgraded to UTF8, these will
be bytes in the resulting string too, causing errors. If you pass data
of different encoding, or you don't know if there is different
encoding, force it to be upgraded before you pass them on:
$csv->print ($fh, [ map { utf8::upgrade (my $x = $_); $x } @data ]);
SPECIFICATION
While no formal specification for CSV exists, RFC 4180 1) describes a
common format and establishes "text/csv" as the MIME type registered
with the IANA.
Many informal documents exist that describe the CSV format. How To: The
Comma Separated Value (CSV) File Format 2) provides an overview of the
CSV format in the most widely used applications and explains how it can
best be used and supported.
1) http://tools.ietf.org/html/rfc4180
2) http://www.creativyst.com/Doc/Articles/CSV/CSV01.htm
The basic rules are as follows:
CSV is a delimited data format that has fields/columns separated by the
comma character and records/rows separated by newlines. Fields that
contain a special character (comma, newline, or double quote), must be
enclosed in double quotes. However, if a line contains a single entry
that is the empty string, it may be enclosed in double quotes. If a
field's value contains a double quote character it is escaped by
placing another double quote character next to it. The CSV file format
does not require a specific character encoding, byte order, or line
terminator format.
· Each record is a single line ended by a line feed (ASCII/LF=0x0A) or
a carriage return and line feed pair (ASCII/CRLF=0x0D 0x0A), however,
line-breaks may be embedded.
· Fields are separated by commas.
· Allowable characters within a CSV field include 0x09 (tab) and the
inclusive range of 0x20 (space) through 0x7E (tilde). In binary mode
all characters are accepted, at least in quoted fields.
· A field within CSV must be surrounded by double-quotes to contain a
the separator character (comma).
Though this is the most clear and restrictive definition, Text::CSV_XS
is way more liberal than this, and allows extension:
· Line termination by a single carriage return is accepted by default
· The separation-, escape-, and escape- characters can be any ASCII
character in the range from 0x20 (space) to 0x7E (tilde). Characters
outside this range may or may not work as expected. Multibyte
characters, like U+060c (ARABIC COMMA), U+FF0C (FULLWIDTH COMMA),
U+241B (SYMBOL FOR ESCAPE), U+2424 (SYMBOL FOR NEWLINE), U+FF02
(FULLWIDTH QUOTATION MARK), and U+201C (LEFT DOUBLE QUOTATION MARK)
(to give some examples of what might look promising) are therefor not
allowed.
If you use perl-5.8.2 or higher, these three attributes are
utf8-decoded, to increase the likelihood of success. This way U+00FE
will be allowed as a quote character.
· A field within CSV must be surrounded by double-quotes to contain an
embedded double-quote, represented by a pair of consecutive double-
quotes. In binary mode you may additionally use the sequence ""0"
for representation of a NULL byte.
· Several violations of the above specification may be allowed by
passing options to the object creator.
METHODS
version
(Class method) Returns the current module version.
new
(Class method) Returns a new instance of Text::CSV_XS. The objects
attributes are described by the (optional) hash ref "\%attr".
my $csv = Text::CSV_XS->new ({ attributes ... });
The following attributes are available:
eol The end-of-line string to add to rows for "print" or the record
separator for "getline".
When not passed in a parser instance, the default behavior is to
accept "\n", "\r", and "\r\n", so it is probably safer to not
specify "eol" at all. Passing "undef" or the empty string behave
the same.
When not passed in a generating instance, lines are not terminated
at all, so it is probably wise to pass something you expect. A safe
choice for "eol" on output is either $/ or "\r\n".
Common values for "eol" are "\012" ("\n" or Line Feed), "\015\012"
("\r\n" or Carriage Return, Line Feed), and "\015" ("\r" or
Carriage Return). The "eol" attribute cannot exceed 7 (ASCII)
characters.
If both $/ and "eol" equal "\015", parsing lines that end on only a
Carriage Return without Line Feed, will be "parse"d correct.
sep_char
The char used to separate fields, by default a comma. (",").
Limited to a single-byte character, usually in the range from 0x20
(space) to 0x7e (tilde).
The separation character can not be equal to the quote character.
The separation character can not be equal to the escape character.
See also "CAVEATS"
allow_whitespace
When this option is set to true, whitespace (TAB's and SPACE's)
surrounding the separation character is removed when parsing. If
either TAB or SPACE is one of the three major characters
"sep_char", "quote_char", or "escape_char" it will not be
considered whitespace.
Now lines like:
1 , "foo" , bar , 3 , zapp
are correctly parsed, even though it violates the CSV specs.
Note that all whitespace is stripped from start and end of each
field. That would make it more a feature than a way to enable
parsing bad CSV lines, as
1, 2.0, 3, ape , monkey
will now be parsed as
("1", "2.0", "3", "ape", "monkey")
even if the original line was perfectly sane CSV.
blank_is_undef
Under normal circumstances, CSV data makes no distinction between
quoted- and unquoted empty fields. These both end up in an empty
string field once read, thus
1,"",," ",2
is read as
("1", "", "", " ", "2")
When writing CSV files with "always_quote" set, the unquoted empty
field is the result of an undefined value. To make it possible to
also make this distinction when reading CSV data, the
"blank_is_undef" option will cause unquoted empty fields to be set
to undef, causing the above to be parsed as
("1", "", undef, " ", "2")
empty_is_undef
Going one step further than "blank_is_undef", this attribute
converts all empty fields to undef, so
1,"",," ",2
is read as
(1, undef, undef, " ", 2)
Note that this effects only fields that are really empty, not
fields that are empty after stripping allowed whitespace. YMMV.
quote_char
The character to quote fields containing blanks, by default the
double quote character ("""). A value of undef suppresses quote
chars (for simple cases only). Limited to a single-byte character,
usually in the range from 0x20 (space) to 0x7e (tilde).
The quote character can not be equal to the separation character.
allow_loose_quotes
By default, parsing fields that have "quote_char" characters inside
an unquoted field, like
1,foo "bar" baz,42
would result in a parse error. Though it is still bad practice to
allow this format, we cannot help the fact some vendors make their
applications spit out lines styled that way.
If there is really bad CSV data, like
1,"foo "bar" baz",42
or
1,""foo bar baz"",42
there is a way to get that parsed, and leave the quotes inside the
quoted field as-is. This can be achieved by setting
"allow_loose_quotes" AND making sure that the "escape_char" is not
equal to "quote_char".
escape_char
The character to escape certain characters inside quoted fields.
Limited to a single-byte character, usually in the range from 0x20
(space) to 0x7e (tilde).
The "escape_char" defaults to being the literal double-quote mark
(""") in other words, the same as the default "quote_char". This
means that doubling the quote mark in a field escapes it:
"foo","bar","Escape ""quote mark"" with two ""quote marks""","baz"
If you change the default quote_char without changing the default
escape_char, the escape_char will still be the quote mark. If
instead you want to escape the quote_char by doubling it, you will
need to change the escape_char to be the same as what you changed
the quote_char to.
The escape character can not be equal to the separation character.
allow_loose_escapes
By default, parsing fields that have "escape_char" characters that
escape characters that do not need to be escaped, like:
my $csv = Text::CSV_XS->new ({ escape_char => "\\" });
$csv->parse (qq{1,"my bar\'s",baz,42});
would result in a parse error. Though it is still bad practice to
allow this format, this option enables you to treat all escape
character sequences equal.
allow_unquoted_escape
There is a backward compatibility issue in that the escape
character, when differing from the quotation character, cannot be
on the first position of a field. e.g. with "quote_char" equal to
the default """ and "escape_char" set to "\", this would be
illegal:
1,\0,2
To overcome issues with backward compatibility, you can allow this
by setting this attribute to 1.
binary
If this attribute is TRUE, you may use binary characters in quoted
fields, including line feeds, carriage returns and NULL bytes. (The
latter must be escaped as ""0".) By default this feature is off.
If a string is marked UTF8, binary will be turned on automatically
when binary characters other than CR or NL are encountered. Note
that a simple string like "\x{00a0}" might still be binary, but not
marked UTF8, so setting "{ binary =" 1 }> is still a wise option.
decode_utf8
This attributes defaults to TRUE.
While parsing, fields that are valid UTF-8, are automatically set
to be UTF-8, so that
$csv->parse ("\xC4\xA8\n");
results in
PV("\304\250"\0) [UTF8 "\x{128}"]
Sometimes it might not be a desired action. To prevent those
upgrades, set this attribute to false, and the result will be
PV("\304\250"\0)
types
A set of column types; this attribute is immediately passed to the
"types" method. You must not set this attribute otherwise, except
for using the "types" method.
always_quote
By default the generated fields are quoted only if they need to be.
For example, if they contain the separator character. If you set
this attribute to a TRUE value, then all defined fields will be
quoted. ("undef" fields are not quoted, see "blank_is_undef")).
This is typically easier to handle in external applications. (Poor
creatures who are not using Text::CSV_XS. :-)
quote_space
By default, a space in a field would trigger quotation. As no rule
exists this to be forced in CSV, nor any for the opposite, the
default is true for safety. You can exclude the space from this
trigger by setting this attribute to 0.
quote_null
By default, a NULL byte in a field would be escaped. This attribute
enables you to treat the NULL byte as a simple binary character in
binary mode (the "{ binary => 1 }" is set). The default is true.
You can prevent NULL escapes by setting this attribute to 0.
quote_binary
By default, all "unsafe" bytes inside a string cause the combined
field to be quoted. By setting this attribute to 0, you can disable
that trigger for bytes >= 0x7f.
keep_meta_info
By default, the parsing of input lines is as simple and fast as
possible. However, some parsing information - like quotation of
the original field - is lost in that process. Set this flag to true
to enable retrieving that information after parsing with the
methods "meta_info", "is_quoted", and "is_binary" described below.
Default is false.
verbatim
This is a quite controversial attribute to set, but it makes hard
things possible.
The basic thought behind this is to tell the parser that the
normally special characters newline (NL) and Carriage Return (CR)
will not be special when this flag is set, and be dealt with as
being ordinary binary characters. This will ease working with data
with embedded newlines.
When "verbatim" is used with "getline", "getline" auto-chomp's
every line.
Imagine a file format like
M^^Hans^Janssen^Klas 2\n2A^Ja^11-06-2007#\r\n
where, the line ending is a very specific "#\r\n", and the sep_char
is a ^ (caret). None of the fields is quoted, but embedded binary
data is likely to be present. With the specific line ending, that
should not be too hard to detect.
By default, Text::CSV_XS' parse function is instructed to only know
about "\n" and "\r" to be legal line endings, and so has to deal
with the embedded newline as a real end-of-line, so it can scan the
next line if binary is true, and the newline is inside a quoted
field. With this attribute, we tell parse () to parse the line as
if "\n" is just nothing more than a binary character.
For parse () this means that the parser has no idea about line
ending anymore, and getline () chomps line endings on reading.
auto_diag
Set to a true number between 1 and 9 will cause "error_diag" to be
automatically be called in void context upon errors.
In case of error "2012 - EOF", this call will be void.
If set to a value greater than 1, it will die on errors instead of
warn. If set to anything unsupported, it will be silently ignored.
Future extensions to this feature will include more reliable auto-
detection of the "autodie" module being enabled, which will raise
the value of "auto_diag" with 1 on the moment the error is
detected.
diag_verbose
Set the verbosity of the "auto_diag" output. Currently only adds
the current input line (if known) to the diagnostic output with an
indication of the position of the error.
callbacks
See the "Callbacks" section below.
To sum it up,
$csv = Text::CSV_XS->new ();
is equivalent to
$csv = Text::CSV_XS->new ({
quote_char => '"',
escape_char => '"',
sep_char => ',',
eol => $\,
always_quote => 0,
quote_space => 1,
quote_null => 1,
quote_binary => 1,
binary => 0,
decode_utf8 => 1,
keep_meta_info => 0,
allow_loose_quotes => 0,
allow_loose_escapes => 0,
allow_unquoted_escape => 0,
allow_whitespace => 0,
blank_is_undef => 0,
empty_is_undef => 0,
verbatim => 0,
auto_diag => 0,
diag_verbose => 0,
callbacks => undef,
});
For all of the above mentioned flags, an accessor method is available
where you can inquire the current value, or change the value
my $quote = $csv->quote_char;
$csv->binary (1);
It is unwise to change these settings halfway through writing CSV data
to a stream. If however, you want to create a new stream using the
available CSV object, there is no harm in changing them.
If the "new" constructor call fails, it returns "undef", and makes the
fail reason available through the "error_diag" method.
$csv = Text::CSV_XS->new ({ ecs_char => 1 }) or
die "".Text::CSV_XS->error_diag ();
"error_diag" will return a string like
"INI - Unknown attribute 'ecs_char'"
print
$status = $csv->print ($io, $colref);
Similar to "combine" + "string" + "print", but way more efficient. It
expects an array ref as input (not an array!) and the resulting string
is not really created, but immediately written to the $io object,
typically an IO handle or any other object that offers a "print"
method.
For performance reasons the print method does not create a result
string. In particular the "string", "status", "fields", and
"error_input" methods are meaningless after executing this method.
If $colref is "undef" (explicit, not through a variable argument) and
"bind_columns" was used to specify fields to be printed, it is possible
to make performance improvements, as otherwise data would have to be
copied as arguments to the method call:
$csv->bind_columns (\($foo, $bar));
$status = $csv->print ($fh, undef);
A short benchmark
my @data = ("aa" .. "zz");
$csv->bind_columns (\(@data));
$csv->print ($io, [ @data ]); # 10800 recs/sec
$csv->print ($io, \@data ); # 57100 recs/sec
$csv->print ($io, undef ); # 50500 recs/sec
combine
$status = $csv->combine (@columns);
This object function constructs a CSV string from the arguments,
returning success or failure. Failure can result from lack of
arguments or an argument containing an invalid character. Upon
success, "string" can be called to retrieve the resultant CSV string.
Upon failure, the value returned by "string" is undefined and
"error_input" can be called to retrieve an invalid argument.
string
$line = $csv->string ();
This object function returns the input to "parse" or the resultant CSV
string of "combine", whichever was called more recently.
getline
$colref = $csv->getline ($io);
This is the counterpart to "print", as "parse" is the counterpart to
"combine": It reads a row from the IO object using "$io->getline" and
parses this row into an array ref. This array ref is returned by the
function or undef for failure.
When fields are bound with "bind_columns", the return value is a
reference to an empty list.
The "string", "fields", and "status" methods are meaningless, again.
getline_all
$arrayref = $csv->getline_all ($io);
$arrayref = $csv->getline_all ($io, $offset);
$arrayref = $csv->getline_all ($io, $offset, $length);
This will return a reference to a list of getline ($io) results. In
this call, "keep_meta_info" is disabled. If $offset is negative, as
with "splice", only the last "abs ($offset)" records of $io are taken
into consideration.
Given a CSV file with 10 lines:
lines call
----- ---------------------------------------------------------
0..9 $csv->getline_all ($io) # all
0..9 $csv->getline_all ($io, 0) # all
8..9 $csv->getline_all ($io, 8) # start at 8
- $csv->getline_all ($io, 0, 0) # start at 0 first 0 rows
0..4 $csv->getline_all ($io, 0, 5) # start at 0 first 5 rows
4..5 $csv->getline_all ($io, 4, 2) # start at 4 first 2 rows
8..9 $csv->getline_all ($io, -2) # last 2 rows
6..7 $csv->getline_all ($io, -4, 2) # first 2 of last 4 rows
parse
$status = $csv->parse ($line);
This object function decomposes a CSV string into fields, returning
success or failure. Failure can result from a lack of argument or the
given CSV string is improperly formatted. Upon success, "fields" can
be called to retrieve the decomposed fields . Upon failure, the value
returned by "fields" is undefined and "error_input" can be called to
retrieve the invalid argument.
You may use the "types" method for setting column types. See "types"'
description below.
getline_hr
The "getline_hr" and "column_names" methods work together to allow you
to have rows returned as hashrefs. You must call "column_names" first
to declare your column names.
$csv->column_names (qw( code name price description ));
$hr = $csv->getline_hr ($io);
print "Price for $hr->{name} is $hr->{price} EUR\n";
"getline_hr" will croak if called before "column_names".
Note that "getline_hr" creates a hashref for every row and will be much
slower than the combined use of "bind_columns" and "getline" but still
offering the same ease of use hashref inside the loop:
my @cols = @{$csv->getline ($io)};
$csv->column_names (@cols);
while (my $row = $csv->getline_hr ($io)) {
print $row->{price};
}
Could easily be rewritten to the much faster:
my @cols = @{$csv->getline ($io)};
my $row = {};
$csv->bind_columns (\@{$row}{@cols});
while ($csv->getline ($io)) {
print $row->{price};
}
Your mileage may vary for the size of the data and the number of rows.
With perl-5.14.2 the comparison for a 100_000 line file with 14 rows:
Rate hashrefs getlines
hashrefs 1.00/s -- -76%
getlines 4.15/s 313% --
getline_hr_all
$arrayref = $csv->getline_hr_all ($io);
$arrayref = $csv->getline_hr_all ($io, $offset);
$arrayref = $csv->getline_hr_all ($io, $offset, $length);
This will return a reference to a list of getline_hr ($io) results. In
this call, "keep_meta_info" is disabled.
print_hr
$csv->print_hr ($io, $ref);
Provides an easy way to print a $ref as fetched with getline_hr
provided the column names are set with column_names.
It is just a wrapper method with basic parameter checks over
$csv->print ($io, [ map { $ref->{$_} } $csv->column_names ]);
fragment
This function tries to implement RFC7111 (URI Fragment Identifiers for
the text/csv Media Type) - http://tools.ietf.org/html/rfc7111
my $AoA = $csv->fragment ($io, $spec);
In specifications, "*" is used to specify the last item, a dash ("-")
to indicate a range. All indices are 1-based: the first row or column
has index 1. Selections on row and column can be combined with the
semi-colon (";").
When using this method in combination with "column_names", the returned
reference will point to a list of hashes instead of to a list of lists.
$csv->column_names ("Name", "Age");
my $AoH = $csv->fragment ($io, "col=3;8");
If the "after_parse" callback is active, it is also called on every
line parsed and skipped before the fragment.
row
row=4
row=5-7
row=6-*
row=1-2;4;6-*
col
col=2
col=1-3
col=4-*
col=1-2;4;7-*
cell
In cell-based selection, the comma (",") is used to pair row and
column
cell=4,1
The range operator using cells can be used to define top-left and
bottom-right cell location
cell=3,1-4,6
RFC7111 does not allow any combination of the three selection methods.
Passing an invalid fragment specification will croak and set error
2013.
column_names
Set the keys that will be used in the "getline_hr" calls. If no keys
(column names) are passed, it'll return the current setting as a list.
"column_names" accepts a list of scalars (the column names) or a single
array_ref, so you can pass "getline"
$csv->column_names ($csv->getline ($io));
"column_names" does no checking on duplicates at all, which might lead
to unwanted results. Undefined entries will be replaced with the string
"\cAUNDEF\cA", so
$csv->column_names (undef, "", "name", "name");
$hr = $csv->getline_hr ($io);
Will set "$hr->{"\cAUNDEF\cA"}" to the 1st field, "$hr->{""}" to the
2nd field, and "$hr->{name}" to the 4th field, discarding the 3rd
field.
"column_names" croaks on invalid arguments.
bind_columns
Takes a list of references to scalars to be printed with "print" or to
store the fields fetched by "getline" in. When you don't pass enough
references to store the fetched fields in, "getline" will fail. If you
pass more than there are fields to return, the remaining references are
left untouched.
$csv->bind_columns (\$code, \$name, \$price, \$description);
while ($csv->getline ($io)) {
print "The price of a $name is \x{20ac} $price\n";
}
To reset or clear all column binding, call "bind_columns" with a single
argument "undef". This will also clear column names.
$csv->bind_columns (undef);
If no arguments are passed at all, "bind_columns" will return the list
current bindings or "undef" if no binds are active.
eof
$eof = $csv->eof ();
If "parse" or "getline" was used with an IO stream, this method will
return true (1) if the last call hit end of file, otherwise it will
return false (''). This is useful to see the difference between a
failure and end of file.
types
$csv->types (\@tref);
This method is used to force that columns are of a given type. For
example, if you have an integer column, two double columns and a string
column, then you might do a
$csv->types ([Text::CSV_XS::IV (),
Text::CSV_XS::NV (),
Text::CSV_XS::NV (),
Text::CSV_XS::PV ()]);
Column types are used only for decoding columns, in other words by the
"parse" and "getline" methods.
You can unset column types by doing a
$csv->types (undef);
or fetch the current type settings with
$types = $csv->types ();
IV Set field type to integer.
NV Set field type to numeric/float.
PV Set field type to string.
fields
@columns = $csv->fields ();
This object function returns the input to "combine" or the resultant
decomposed fields of a successful "parse", whichever was called more
recently.
Note that the return value is undefined after using "getline", which
does not fill the data structures returned by "parse".
meta_info
@flags = $csv->meta_info ();
This object function returns the flags of the input to "combine" or the
flags of the resultant decomposed fields of "parse", whichever was
called more recently.
For each field, a meta_info field will hold flags that tell something
about the field returned by the "fields" method or passed to the
"combine" method. The flags are bit-wise-or'd like:
" "0x0001
The field was quoted.
" "0x0002
The field was binary.
See the "is_***" methods below.
is_quoted
my $quoted = $csv->is_quoted ($column_idx);
Where $column_idx is the (zero-based) index of the column in the last
result of "parse".
This returns a true value if the data in the indicated column was
enclosed in "quote_char" quotes. This might be important for data where
",20070108," is to be treated as a numeric value, and where
","20070108"," is explicitly marked as character string data.
is_binary
my $binary = $csv->is_binary ($column_idx);
Where $column_idx is the (zero-based) index of the column in the last
result of "parse".
This returns a true value if the data in the indicated column contained
any byte in the range "[\x00-\x08,\x10-\x1F,\x7F-\xFF]".
is_missing
my $missing = $csv->is_missing ($column_idx);
Where $column_idx is the (zero-based) index of the column in the last
result of "getline_hr".
while (my $hr = $csv->getline_hr ($fh)) {
$csv->is_missing (0) and next; # This was an empty line
}
When using "getline_hr" for parsing, it is impossible to tell if the
fields are "undef" because they where not filled in the CSV stream or
because they were not read at all, as all the fields defined by
"column_names" are set in the hash-ref. If you still need to know if
all fields in each row are provided, you should enable "keep_meta_info"
so you can check the flags.
status
$status = $csv->status ();
This object function returns success (or failure) of "combine" or
"parse", whichever was called more recently.
error_input
$bad_argument = $csv->error_input ();
This object function returns the erroneous argument (if it exists) of
"combine" or "parse", whichever was called more recently. If the last
call was successful, "error_input" will return "undef".
error_diag
Text::CSV_XS->error_diag ();
$csv->error_diag ();
$error_code = 0 + $csv->error_diag ();
$error_str = "" . $csv->error_diag ();
($cde, $str, $pos, $recno) = $csv->error_diag ();
If (and only if) an error occurred, this function returns the
diagnostics of that error.
If called in void context, it will print the internal error code and
the associated error message to STDERR.
If called in list context, it will return the error code and the error
message in that order. If the last error was from parsing, the third
value returned is a best guess at the location within the line that was
being parsed. Its value is 1-based. The forth value represents the
record count parsed by this csv object See examples/csv-check for how
this can be used.
If called in scalar context, it will return the diagnostics in a single
scalar, a-la $!. It will contain the error code in numeric context, and
the diagnostics message in string context.
When called as a class method or a direct function call, the error
diagnostics is that of the last "new" call.
record_number
$recno = $csv->record_number ();
Returns the records parsed by this csv instance. This value should be
more accurate than $. when embedded newlines come in play. Records
written by this instance are not counted.
SetDiag
$csv->SetDiag (0);
Use to reset the diagnostics if you are dealing with errors.
FUNCTIONS
csv
This function is not exported by default and should be explicitly
requested:
use Text::CSV_XS qw( csv );
This is the first draft. This function will stay, but the arguments
might change based on user feedback: esp. the "headers" attribute is
not complete. The basics will stay.
This is an high-level function that aims at simple interfaces. It can
be used to read/parse a CSV file or stream (the default behavior) or to
produce a file or write to a stream (define the "out" attribute). It
returns an array reference on parsing (or undef on fail) or the numeric
value of "error_diag" on writing. When this function fails you can get
to the error using the class call to "error_diag"
my $aoa = csv (in => "test.csv") or
die Text::CSV_XS->error_diag;
This function takes the arguments as key-value pairs. It can be passed
as a list or as an anonymous hash:
my $aoa = csv ( in => "test.csv", sep_char => ";");
my $aoh = csv ({ in => $fh, headers => "auto" });
The arguments passed consist of two parts: the arguments to "csv"
itself and the optional attributes to the CSV object used inside the
function as enumerated and explained in "new".
If not overridden, the default options used for CSV are
auto_diag => 1
These options are always set and cannot be altered
binary => 1
in
Used to specify the source. "in" can be a file name (e.g. "file.csv"),
which will be opened for reading and closed when finished, a file
handle (e.g. $fh or "FH"), a reference to a glob (e.g. "\*ARGV"), or
the glob itself (e.g. *STDIN).
When used with "out", it should be a reference to a CSV structure (AoA
or AoH).
my $aoa = csv (in => "file.csv");
open my $fh, "<", "file.csv";
my $aoa = csv (in => $fh);
my $csv = [ [qw( Foo Bar )], [ 1, 2 ], [ 2, 3 ]];
my $err = csv (in => $csv, out => "file.csv");
out
In output mode, the default CSV options when producing CSV are
eol => "\r\n"
The "fragment" attribute is ignored in output mode.
"out" can be a file name (e.g. "file.csv"), which will be opened for
writing and closed when finished, a file handle (e.g. $fh or "FH"), a
reference to a glob (e.g. "\*STDOUT"), or the glob itself (e.g.
*STDOUT).
encoding
If passed, it should be an encoding accepted by the ":encoding()"
option to "open". There is no default value. This attribute does not
work in perl 5.6.x.
headers
If this attribute is not given, the default behavior is to produce an
array of arrays.
If "headers" is given, it should be either an anonymous list of column
names or a flag: "auto" or "skip". When "skip" is used, the header will
not be included in the output.
my $aoa = csv (in => $fh, headers => "skip");
If "auto" is used, the first line of the CSV source will be read as the
list of field headers and used to produce an array of hashes.
my $aoh = csv (in => $fh, headers => "auto");
If "headers" is an anonymous list, it will be used instead
my $aoh = csv (in => $fh, headers => [qw( Foo Bar )]);
csv (in => $aoa, out => $fh, headers => [qw( code description price }]);
fragment
Only output the fragment as defined in the "fragment" method. This
attribute is ignored when generating CSV. See "out".
Combining all of them could give something like
use Text::CSV_XS qw( csv );
my $aoh = csv (
in => "test.txt",
encoding => "utf-8",
headers => "auto",
sep_char => "|",
fragment => "row=3;6-9;15-*",
);
say $aoh->[15]{Foo};
Callbacks
Callbacks enable actions inside "Text::CSV_XS". While most of what this
offers can easily be done in an unrolled loop as described in the
l</SYNOPSIS> callbacks can be used to meet special demands or enhance
the "csv" function.
error
$csv->callbacks (error => sub { $csv->SetDiag (0) });
the "error" callback is invoked when an error occurs, but only when
"auto_diag" is set to a true value. The callback is passed the values
returned by "error_diag":
my ($c, $s);
sub ignore3006
{
my ($err, $msg, $pos, $recno) = @_;
if ($err == 3006) {
# ignore this error
($c, $s) = (undef, undef);
SetDiag (0);
}
# Any other error
return;
} # ignore3006
$csv->callbacks (error => \&ignore3006);
$csv->bind_columns (\$c, \$s);
while ($csv->getline ($fh)) {
# Error 3006 will not stop the loop
}
after_parse
$csv->callbacks (after_parse => sub { push @{$_[1]}, "NEW" });
while (my $row = $csv->getline ($fh)) {
$row->[-1] eq "NEW";
}
This callback is invoked after parsing with "getline" only if no
error occurred. The callback is invoked with two arguments: the
current CSV parser object and an array reference to the fields
parsed.
The return code of the callback is ignored.
sub add_from_db
{
my ($csv, $row) = @_;
$sth->execute ($row->[4]);
push @$row, $sth->fetchrow_array;
} # add_from_db
my $aoa = csv (in => "file.csv", callbacks => {
after_parse => \&add_from_db });
before_print
my $idx = 1;
$csv->callbacks (before_print => sub { $_[1][0] = $idx++ });
$csv->print (*STDOUT, [ 0, $_ ]) for @members;
This callback is invoked before printing with "print" only if no
error occurred. The callback is invoked with two arguments: the
current CSV parser object and an array reference to the fields
passed.
The return code of the callback is ignored.
sub max_4_fields
{
my ($csv, $row) = @_;
@$row > 4 and splice @$row, 4;
} # max_4_fields
csv (in => csv (in => "file.csv"), out => *STDOUT,
callbacks => { before print => \&max_4_fields });
This callback is not active for "combine".
INTERNALS
Combine (...)
Parse (...)
The arguments to these two internal functions are deliberately not
described or documented in order to enable the module author(s) to
change it when they feel the need for it. Using them is highly
discouraged as the API may change in future releases.
EXAMPLES
Reading a CSV file line by line:
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
open my $fh, "<", "file.csv" or die "file.csv: $!";
while (my $row = $csv->getline ($fh)) {
# do something with @$row
}
close $fh or die "file.csv: $!";
Reading only a single column
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
open my $fh, "<", "file.csv" or die "file.csv: $!";
# get only the 4th column
my @column = map { $_->[3] } @{$csv->getline_all ($fh)};
close $fh or die "file.csv: $!";
with "csv", you could do
my @column = map { $_->[0] }
@{csv (in => "file.csv", fragment => "col=4")};
Parsing CSV strings:
my $csv = Text::CSV_XS->new ({ keep_meta_info => 1, binary => 1 });
my $sample_input_string =
qq{"I said, ""Hi!""",Yes,"",2.34,,"1.09","\x{20ac}",};
if ($csv->parse ($sample_input_string)) {
my @field = $csv->fields;
foreach my $col (0 .. $#field) {
my $quo = $csv->is_quoted ($col) ? $csv->{quote_char} : "";
printf "%2d: %s%s%s\n", $col, $quo, $field[$col], $quo;
}
}
else {
print STDERR "parse () failed on argument: ",
$csv->error_input, "\n";
$csv->error_diag ();
}
Printing CSV data
The fast way: using "print"
An example for creating CSV files using the "print" method, like in
dumping the content of a database ($dbh) table ($tbl) to CSV:
my $csv = Text::CSV_XS->new ({ binary => 1, eol => $/ });
open my $fh, ">", "$tbl.csv" or die "$tbl.csv: $!";
my $sth = $dbh->prepare ("select * from $tbl");
$sth->execute;
$csv->print ($fh, $sth->{NAME_lc});
while (my $row = $sth->fetch) {
$csv->print ($fh, $row) or $csv->error_diag;
}
close $fh or die "$tbl.csv: $!";
The slow way: using "combine" and "string"
or using the slower "combine" and "string" methods:
my $csv = Text::CSV_XS->new;
open my $csv_fh, ">", "hello.csv" or die "hello.csv: $!";
my @sample_input_fields = (
'You said, "Hello!"', 5.67,
'"Surely"', '', '3.14159');
if ($csv->combine (@sample_input_fields)) {
print $csv_fh $csv->string, "\n";
}
else {
print "combine () failed on argument: ",
$csv->error_input, "\n";
}
close $csv_fh or die "hello.csv: $!";
Rewriting CSV
Rewrite a CSV file with ";" as separator character to well-formed CSV:
use Text::CSV_XS qw( csv );
csv (in => csv (in => "bad.csv", sep_char => ";"), out => *STDOUT);
The examples folder
For more extended examples, see the examples/ (1) sub-directory in the
original distribution or the git repository (2).
1. http://repo.or.cz/w/Text-CSV_XS.git?a=tree;f=examples
2. http://repo.or.cz/w/Text-CSV_XS.git
The following files can be found there:
parser-xs.pl
This can be used as a boilerplate to `fix' bad CSV and parse beyond
errors.
$ perl examples/parser-xs.pl bad.csv >good.csv
csv-check
This is a command-line tool that uses parser-xs.pl techniques to
check the CSV file and report on its content.
$ csv-check files/utf8.csv
Checked with examples/csv-check 1.5 using Text::CSV_XS 0.81
OK: rows: 1, columns: 2
sep = <,>, quo = <">, bin = <1>
csv2xls
A script to convert CSV to Microsoft Excel. This requires Date::Calc
and Spreadsheet::WriteExcel. The converter accepts various options
and can produce UTF-8 Excel files.
csvdiff
A script that provides colorized diff on sorted CSV files, assuming
first line is header and first field is the key. Output options
include colorized ANSI escape codes or HTML.
$ csvdiff --html --output=diff.html file1.csv file2.csv
CAVEATS
"Text::CSV_XS" is not designed to detect the characters used to quote
and separate fields. The parsing is done using predefined settings. In
the examples sub-directory, you can find scripts that demonstrate how
you can try to detect these characters yourself.
Microsoft Excel
The import/export from Microsoft Excel is a risky task, according to
the documentation in "Text::CSV::Separator". Microsoft uses the
system's default list separator defined in the regional settings, which
happens to be a semicolon for Dutch, German and Spanish (and probably
some others as well). For the English locale, the default is a comma.
In Windows however, the user is free to choose a predefined locale, and
then change every individual setting in it, so checking the locale is
no solution.
TODO
More Errors & Warnings
New extensions ought to be clear and concise in reporting what error
occurred where and why, and possibly also tell a remedy to the
problem. error_diag is a (very) good start, but there is more work
to be done here.
Basic calls should croak or warn on illegal parameters. Errors should
be documented.
setting meta info
Future extensions might include extending the "meta_info",
"is_quoted", and "is_binary" to accept setting these flags for
fields, so you can specify which fields are quoted in the
"combine"/"string" combination.
$csv->meta_info (0, 1, 1, 3, 0, 0);
$csv->is_quoted (3, 1);
Parse the whole file at once
Implement new methods that enable parsing of a complete file at once,
returning a list of hashes. Possible extension to this could be to
enable a column selection on the call:
my @AoH = $csv->parse_file ($filename, { cols => [ 1, 4..8, 12 ]});
Returning something like
[ { fields => [ 1, 2, "foo", 4.5, undef, "", 8 ],
flags => [ ... ],
},
{ fields => [ ... ],
.
},
]
Note that the "csv" function already supports most of this, but does
not return flags. "getline_all" returns all rows for an open stream,
but this will not return flags either. "fragment" can reduce the
required rows or columns, but cannot combine them.
NOT TODO
combined methods
Requests for adding means (methods) that combine "combine" and
"string" in a single call will not be honored. Likewise for "parse"
and "fields". Given the trouble with embedded newlines, using
"getline" and "print" instead is the preferred way to go.
Release plan
No guarantees, but this is what I had in mind some time ago:
next
- DIAGNOSTICS secttion in pod to *describe* the errors (see below)
- croak / carp
EBCDIC
The hard-coding of characters and character ranges makes this module
unusable on EBCDIC systems.
Opening EBCDIC encoded files on ASCII+ systems is likely to succeed
using Encode's cp37, cp1047, or posix-bc:
open my $fh, "<:encoding(cp1047)", "ebcdic_file.csv" or die "...";
DIAGNOSTICS
Still under construction ...
If an error occurred, "$csv-"error_diag> can be used to get more
information on the cause of the failure. Note that for speed reasons,
the internal value is never cleared on success, so using the value
returned by "error_diag" in normal cases - when no error occurred - may
cause unexpected results.
If the constructor failed, the cause can be found using "error_diag" as
a class method, like "Text::CSV_XS-"error_diag>.
"$csv-"error_diag> is automatically called upon error when the
contractor was called with "auto_diag" set to 1 or 2, or when "autodie"
is in effect. When set to 1, this will cause a "warn" with the error
message, when set to 2, it will "die". "2012 - EOF" is excluded from
"auto_diag" reports.
The errors as described below are available. I have tried to make the
error itself explanatory enough, but more descriptions will be added.
For most of these errors, the first three capitals describe the error
category:
· INI
Initialization error or option conflict.
· ECR
Carriage-Return related parse error.
· EOF
End-Of-File related parse error.
· EIQ
Parse error inside quotation.
· EIF
Parse error inside field.
· ECB
Combine error.
· EHR
HashRef parse related error.
And below should be the complete list of error codes that can be
returned:
· 1001 "INI - sep_char is equal to quote_char or escape_char"
The separation character cannot be equal to either the quotation
character or the escape character, as that will invalidate all
parsing rules.
· 1002 "INI - allow_whitespace with escape_char or quote_char SP or
TAB"
Using "allow_whitespace" when either "escape_char" or "quote_char" is
equal to SPACE or TAB is too ambiguous to allow.
· 1003 "INI - \r or \n in main attr not allowed"
Using default "eol" characters in either "sep_char", "quote_char", or
"escape_char" is not allowed.
· 1004 "INI - callbacks should be undef or a hashref"
The "callbacks" attribute only allows to be "undef" or a hash
reference.
· 2010 "ECR - QUO char inside quotes followed by CR not part of EOL"
When "eol" has been set to something specific, other than the
default, like "\r\t\n", and the "\r" is following the second
(closing) "quote_char", where the characters following the "\r" do
not make up the "eol" sequence, this is an error.
· 2011 "ECR - Characters after end of quoted field"
Sequences like "1,foo,"bar"baz,2" are not allowed. "bar" is a quoted
field, and after the closing quote, there should be either a new-line
sequence or a separation character.
· 2012 "EOF - End of data in parsing input stream"
Self-explaining. End-of-file while inside parsing a stream. Can
happen only when reading from streams with "getline", as using
"parse" is done on strings that are not required to have a trailing
"eol".
· 2013 "INI - Specification error for fragments RFC7111"
Invalid specification for URI "fragment" specification.
· 2021 "EIQ - NL char inside quotes, binary off"
Sequences like "1,"foo\nbar",2" are allowed only when the binary
option has been selected with the constructor.
· 2022 "EIQ - CR char inside quotes, binary off"
Sequences like "1,"foo\rbar",2" are allowed only when the binary
option has been selected with the constructor.
· 2023 "EIQ - QUO character not allowed"
Sequences like ""foo "bar" baz",quux" and "2023,",2008-04-05,"Foo,
Bar",\n" will cause this error.
· 2024 "EIQ - EOF cannot be escaped, not even inside quotes"
The escape character is not allowed as last character in an input
stream.
· 2025 "EIQ - Loose unescaped escape"
An escape character should escape only characters that need escaping.
Allowing the escape for other characters is possible with the
"allow_loose_escape" attribute.
· 2026 "EIQ - Binary character inside quoted field, binary off"
Binary characters are not allowed by default. Exceptions are fields
that contain valid UTF-8, that will automatically be upgraded is the
content is valid UTF-8. Pass the "binary" attribute with a true value
to accept binary characters.
· 2027 "EIQ - Quoted field not terminated"
When parsing a field that started with a quotation character, the
field is expected to be closed with a quotation character. When the
parsed line is exhausted before the quote is found, that field is not
terminated.
· 2030 "EIF - NL char inside unquoted verbatim, binary off"
· 2031 "EIF - CR char is first char of field, not part of EOL"
· 2032 "EIF - CR char inside unquoted, not part of EOL"
· 2034 "EIF - Loose unescaped quote"
· 2035 "EIF - Escaped EOF in unquoted field"
· 2036 "EIF - ESC error"
· 2037 "EIF - Binary character in unquoted field, binary off"
· 2110 "ECB - Binary character in Combine, binary off"
· 2200 "EIO - print to IO failed. See errno"
· 3001 "EHR - Unsupported syntax for column_names ()"
· 3002 "EHR - getline_hr () called before column_names ()"
· 3003 "EHR - bind_columns () and column_names () fields count
mismatch"
· 3004 "EHR - bind_columns () only accepts refs to scalars"
· 3006 "EHR - bind_columns () did not pass enough refs for parsed
fields"
· 3007 "EHR - bind_columns needs refs to writable scalars"
· 3008 "EHR - unexpected error in bound fields"
· 3009 "EHR - print_hr () called before column_names ()"
· 3010 "EHR - print_hr () called with invalid arguments"
SEE ALSO
perl, IO::File, IO::Handle, IO::Wrap, Text::CSV, Text::CSV_PP,
Text::CSV::Encoded, Text::CSV::Separator, and Spreadsheet::Read.
AUTHORS and MAINTAINERS
Alan Citterman <alan@mfgrtl.com> wrote the original Perl module.
Please don't send mail concerning Text::CSV_XS to Alan, as he's not
involved in the C part that is now the main part of the module.
Jochen Wiedmann <joe@ispsoft.de> rewrote the encoding and decoding in C
by implementing a simple finite-state machine and added the variable
quote, escape and separator characters, the binary mode and the print
and getline methods. See ChangeLog releases 0.10 through 0.23.
H.Merijn Brand <h.m.brand@xs4all.nl> cleaned up the code, added the
field flags methods, wrote the major part of the test suite, completed
the documentation, fixed some RT bugs and added all the allow flags.
See ChangeLog releases 0.25 and on.
COPYRIGHT AND LICENSE
Copyright (C) 2007-2014 H.Merijn Brand. All rights reserved.
Copyright (C) 1998-2001 Jochen Wiedmann. All rights reserved.
Copyright (C) 1997 Alan Citterman. All rights reserved.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.2 2014-03-06 CSV_XS(3)
