Text::CSV
Text::CSV(3) User Contributed Perl Documentation Text::CSV(3)
NAME
Text::CSV - comma-separated values manipulator (using XS or PurePerl)
SYNOPSIS
use Text::CSV;
$csv = Text::CSV->new(); # create a new object
# If you want to handle non-ascii char.
$csv = Text::CSV->new({binary => 1});
$status = $csv->combine(@columns); # combine columns into a string
$line = $csv->string(); # get the combined string
$status = $csv->parse($line); # parse a CSV string into fields
@columns = $csv->fields(); # get the parsed fields
$status = $csv->status (); # get the most recent status
$bad_argument = $csv->error_input (); # get the most recent bad argument
$diag = $csv->error_diag (); # if an error occured, explains WHY
$status = $csv->print ($io, $colref); # Write an array of fields
# immediately to a file $io
$colref = $csv->getline ($io); # Read a line from file $io,
# parse it and return an array
# ref of fields
$csv->column_names (@names); # Set column names for getline_hr ()
$ref = $csv->getline_hr ($io); # getline (), but returns a hashref
$eof = $csv->eof (); # Indicate if last parse or
# getline () hit End Of File
$csv->types(\@t_array); # Set column types
DESCRIPTION
Text::CSV provides facilities for the composition and decomposition of
comma-separated values using Text::CSV_XS or its pure Perl version.
An instance of the Text::CSV class can combine fields into a CSV
string and parse a CSV string into fields.
The module accepts either strings or files as input and can utilize
any user-specified characters as delimiters, separators, and escapes
so it is perhaps better called ASV (anything separated values) rather
than just CSV.
VERSION
1.12
This module is compatible with Text::CSV_XS 0.65 and later.
BINARY MODE
The default behavior is to only accept ascii characters. In many
cases, you should create a Text::CSV object with binary mode.
my $csv = Text::CSV->new({binary => 1});
See to "Embedded newlines" in Text::CSV_XS.
Unicode (UTF8)
On parsing (both for "getline ()" and "parse ()"), if the source is
marked being UTF8, then parsing that source will mark all fields that
are marked binary will also be marked UTF8.
On combining ("print ()" and "combine ()"), if any of the combining
fields was marked UTF8, the resulting string will 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
$csv = Text::CSV::Encoded->new ({ encoding => undef }); # default
# combine () and print () accept UTF8 marked data
# parse () and getline () return UTF8 marked data
SPECIFICATION
See to "SPECIFICATION" in Text::CSV_XS.
FUNCTIONS
These methods are common between XS and puer Perl version. Most of
the document was shamelessly copied and replaced from Text::CSV_XS.
version ()
(Class method) Returns the current backend module version. If you
want the module version, you can use the "VERSION" method,
print Text::CSV->VERSION; # This module version
print Text::CSV->version; # The version of the worker module
# same as Text::CSV->backend->version
new (\%attr)
(Class method) Returns a new instance of Text::CSV_XS. The objects
attributes are described by the (optional) hash ref "\%attr". Cur-
rently the following attributes are available:
eol An end-of-line string to add to rows. "undef" is replaced with an
empty string. The default is "$\". Common values for "eol" are
"\012" (Line Feed) or "\015\012" (Carriage Return, Line Feed).
Cannot be longer than 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.
Line endings, whether in $/ or "eol", other than "undef", "\n",
"\r\n", or "\r" are not (yet) supported for parsing.
sep_char
The char used for separating 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" in Text::CSV_XS
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 consid-
ered whitespace.
1 , "foo" , bar , 3 , zapp
are now 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 is more a feature than a way to be able to
parse 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. They both end up in an empty
string field once read, so
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")
quote_char
The char used for quoting 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 charac-
ter, 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 there are some vendors that make
their applications spit out lines styled like this.
In case 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 used for escaping 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->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.
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.
types
A set of column types; this attribute is immediately passed to the
types method below. You must not set this attribute otherwise,
except for using the types method. For details see the description
of the types method below.
always_quote
By default the generated fields are quoted only, if they need to,
for example, if they contain the separator. If you set this
attribute to a TRUE value, then all fields will be quoted. This is
typically easier to handle in external applications.
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 be able to retrieve 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 nor-
mally 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 embed-
ded binary data is likely to be present. With the specific line
ending, that shouldn’t be too hard to detect.
By default, Text::CSV’ parse function however 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 however, we can 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.
To sum it up,
$csv = Text::CSV->new ();
is equivalent to
$csv = Text::CSV->new ({
quote_char => ’"’,
escape_char => ’"’,
sep_char => ’,’,
eol => $\,
always_quote => 0,
binary => 0,
keep_meta_info => 0,
allow_loose_quotes => 0,
allow_loose_escapes => 0,
allow_whitespace => 0,
blank_is_undef => 0,
verbatim => 0,
});
For all of the above mentioned flags, there is an accessor method
available where you can inquire for 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->new ({ ecs_char => 1 }) or
die Text::CSV->error_diag ();
"error_diag ()" will return a string like
"Unknown attribute ’ecs_char’"
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 argu-
ments 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.
print
$status = $csv->print ($io, $colref);
Similar to combine, but it expects an array ref as input (not an
array!) and the resulting string is not really created, but immedi-
ately written to the $io object, typically an IO handle or any other
object that offers a print method. Note, this implies that the follow-
ing is wrong:
open FILE, ">", "whatever";
$status = $csv->print (\*FILE, $colref);
The glob "\*FILE" is not an object, thus it doesn’t have a print
method. The solution is to use an IO::File object or to hide the glob
behind an IO::Wrap object. See IO::File(3) and IO::Wrap(3) for
details.
For performance reasons the print method doesn’t create a result
string. In particular the $csv->string (), $csv->status (),
$csv-fields ()> and $csv->error_input () methods are meaningless after
executing this method.
string
$line = $csv->string ();
This object function returns the input to "parse ()" or the resultant
CSV string of "combine ()", whichever was called more recently.
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 the
description below.
getline
$colref = $csv->getline ($io);
This is the counterpart to print, like parse is the counterpart to
combine: It reads a row from the IO object $io 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 $csv->string (), $csv->fields () and $csv->status () methods are
meaningless, again.
getline_hr
The "getline_hr ()" and "column_names ()" methods work together to
allow you to have rows returned as hashrefs. You must call "col-
umn_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 ()".
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.
"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 2rd
field.
"column_names ()" croaks on invalid arguments.
bind_columns
Takes a list of references to scalars to store the fields fetched
"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 ()) {
print "The price of a $name is \x{20ac} $price\n";
}
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::IV (),
Text::CSV::NV (),
Text::CSV::NV (),
Text::CSV::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 resul-
tant decomposed fields of "parse ()", whichever was called more
recently.
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 bitwise-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 con-
tained any byte in the range [\x00-\x08,\x10-\x1F,\x7F-\xFF]
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.
error_diag
$csv->error_diag ();
$error_code = 0 + $csv->error_diag ();
$error_str = "" . $csv->error_diag ();
($cde, $str, $pos) = $csv->error_diag ();
If (and only if) an error occured, this function returns the diagnos-
tics 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 the best guess at the location within the line that
was being parsed. It’s value is 1-based.
Note: $pos returned by the backend Text::CSV_PP does not show the
error point in many cases (see to the below line). It is for con-
science’s sake in using Text::CSV_PP.
If called in scalar context, it will return the diagnostics in a sin-
gle scalar, a-la $!. It will contain the error code in numeric con-
text, and the diagnostics message in string context.
Depending on the used worker module, returned diagnostics is difffer-
ent.
Text::CSV_XS parses csv strings by dividing one character while
Text::CSV_PP by using the regular expressions. That difference makes
the different cause of the failure.
SetDiag
$csv->SetDiag (0);
Use to reset the diagnostics if you are dealing with errors.
Some methods are Text::CSV only.
backend
Returns the backend module name called by Text::CSV. "module" is
an alias.
is_xs
Returns true value if Text::CSV or the object uses XS module as
worker.
is_pp
Returns true value if Text::CSV or the object uses pure-Perl mod-
ule as worker.
DIAGNOSTICS
If an error occured, $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 occured -
may cause unexpected results.
This function changes depending on the used module (XS or PurePerl).
See to "DIAGNOSTICS" in Text::CSV_XS and "DIAGNOSTICS" in
Text::CSV_PP.
HISTORY AND WORKER MODULES
This module, Text::CSV was firstly written by Alan Citterman which
could deal with only ascii characters. Then, Jochen Wiedmann wrote
Text::CSV_XS which has the binary mode. This XS version is maintained
by H.Merijn Brand and Text::CSV_PP written by Makamaka was pure-Perl
version of Text::CSV_XS.
Now, Text::CSV was rewritten by Makamaka and become a wrapper to
Text::CSV_XS or Text::CSV_PP. Text::CSV_PP will be bundled in this
distribution.
When you use Text::CSV, it calls a backend worker module -
Text::CSV_XS or Text::CSV_PP. By default, Text::CSV tries to use
Text::CSV_XS which must be complied and installed properly. If this
call is fail, Text::CSV uses Text::CSV_PP.
The required Text::CSV_XS version is 0.41 in Text::CSV version 1.03.
If you set an enviornment variable "PERL_TEXT_CSV", The calling action
will be changed.
PERL_TEXT_CSV = 0
PERL_TEXT_CSV = ’Text::CSV_PP’
Always use Text::CSV_PP
PERL_TEXT_CSV = 1
PERL_TEXT_CSV = ’Text::CSV_XS,Text::CSV_PP’
(The default) Use compiled Text::CSV_XS if it is properly compiled
& installed, otherwise use Text::CSV_PP
PERL_TEXT_CSV = 2
PERL_TEXT_CSV = ’Text::CSV_XS’
Always use compiled Text::CSV_XS, die if it isn’t properly com-
piled & installed.
These ideas come from DBI::PurePerl mechanism.
example:
BEGIN { $ENV{PERL_TEXT_CSV} = 0 }
use Text::CSV; # always uses Text::CSV_PP
In future, it may be able to specify another module.
TODO
Wrapper mechanism
Currently the wrapper mechanism is to change symbolic table for
speed.
for my $method (@PublicMethods) {
*{"Text::CSV::$method"} = \&{"$class\::$method"};
}
But how about it - calling worker module object?
sub parse {
my $self = shift;
$self->{_WORKER_OBJECT}->parse(@_); # XS or PP CSV object
}
See to "TODO" in Text::CSV_XS and "TODO" in Text::CSV_PP.
SEE ALSO
Text::CSV_PP, Text::CSV_XS and Text::CSV::Encoded.
AUTHORS and MAINTAINERS
Alan Citterman <alan[at]mfgrtl.com> wrote the original Perl module.
Please don’t send mail concerning Text::CSV to Alan, as he’s not a
present maintainer.
Jochen Wiedmann <joe[at]ispsoft.de> rewrote the encoding and decoding
in C by implementing a simple finite-state machine and added the vari-
able 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[at]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. See ChangeLog releases 0.25 and
on.
Makamaka Hannyaharamitu, <makamaka[at]cpan.org> wrote Text::CSV_PP
which is the pure-Perl version of Text::CSV_XS.
New Text::CSV (since 0.99) is maintained by Makamaka.
COPYRIGHT AND LICENSE
Text::CSV
Copyright (C) 1997 Alan Citterman. All rights reserved. Copyright (C)
2007-2009 Makamaka Hannyaharamitu.
Text::CSV_PP:
Copyright (C) 2005-2009 Makamaka Hannyaharamitu.
Text:CSV_XS:
Copyright (C) 2007-2009 H.Merijn Brand for PROCURA B.V. Copyright (C)
1998-2001 Jochen Wiedmann. All rights reserved. Portions 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 v5.8.8 2009-05-15 Text::CSV(3)
