csv(3tcl) CSV processing csv(3tcl)
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NAME
csv - Procedures to handle CSV data.
SYNOPSIS
package require Tcl 8.4
package require csv ?0.8.1?
::csv::iscomplete data
::csv::join values ?sepChar? ?delChar? ?delMode?
::csv::joinlist values ?sepChar? ?delChar? ?delMode?
::csv::joinmatrix matrix ?sepChar? ?delChar? ?delMode?
::csv::read2matrix ?-alternate? chan m {sepChar ,} {expand none}
::csv::read2queue ?-alternate? chan q {sepChar ,}
::csv::report cmd matrix ?chan?
::csv::split ?-alternate? line ?sepChar? ?delChar?
::csv::split2matrix ?-alternate? m line {sepChar ,} {expand none}
::csv::split2queue ?-alternate? q line {sepChar ,}
::csv::writematrix m chan ?sepChar? ?delChar?
::csv::writequeue q chan ?sepChar? ?delChar?
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DESCRIPTION
The csv package provides commands to manipulate information in CSV FOR-
MAT (CSV = Comma Separated Values).
COMMANDS
The following commands are available:
::csv::iscomplete data
A predicate checking if the argument data is a complete csv
record. The result is a boolean flag indicating the completeness
of the data. The result is true if the data is complete.
::csv::join values ?sepChar? ?delChar? ?delMode?
Takes a list of values and returns a string in CSV format con-
taining these values. The separator character can be defined by
the caller, but this is optional. The default is ",". The quot-
ing aka delimiting character can be defined by the caller, but
this is optional. The default is '"'. By default the quoting
mode delMode is "auto", surrounding values with delChar only
when needed. When set to "always" however, values are always
surrounded by the delChar instead.
::csv::joinlist values ?sepChar? ?delChar? ?delMode?
Takes a list of lists of values and returns a string in CSV for-
mat containing these values. The separator character can be de-
fined by the caller, but this is optional. The default is ",".
The quoting character can be defined by the caller, but this is
optional. The default is '"'. By default the quoting mode
delMode is "auto", surrounding values with delChar only when
needed. When set to "always" however, values are always sur-
rounded by the delChar instead. Each element of the outer list
is considered a record, these are separated by newlines in the
result. The elements of each record are formatted as usual (via
::csv::join).
::csv::joinmatrix matrix ?sepChar? ?delChar? ?delMode?
Takes a matrix object following the API specified for the
struct::matrix package and returns a string in CSV format con-
taining these values. The separator character can be defined by
the caller, but this is optional. The default is ",". The quot-
ing character can be defined by the caller, but this is op-
tional. The default is '"'. By default the quoting mode delMode
is "auto", surrounding values with delChar only when needed.
When set to "always" however, values are always surrounded by
the delChar instead. Each row of the matrix is considered a
record, these are separated by newlines in the result. The ele-
ments of each record are formatted as usual (via ::csv::join).
::csv::read2matrix ?-alternate? chan m {sepChar ,} {expand none}
A wrapper around ::csv::split2matrix (see below) reading CSV-
formatted lines from the specified channel (until EOF) and
adding them to the given matrix. For an explanation of the ex-
pand argument see ::csv::split2matrix.
::csv::read2queue ?-alternate? chan q {sepChar ,}
A wrapper around ::csv::split2queue (see below) reading CSV-for-
matted lines from the specified channel (until EOF) and adding
them to the given queue.
::csv::report cmd matrix ?chan?
A report command which can be used by the matrix methods format
2string and format 2chan. For the latter this command delegates
the work to ::csv::writematrix. cmd is expected to be either
printmatrix or printmatrix2channel. The channel argument, chan,
has to be present for the latter and must not be present for the
first.
::csv::split ?-alternate? line ?sepChar? ?delChar?
converts a line in CSV format into a list of the values con-
tained in the line. The character used to separate the values
from each other can be defined by the caller, via sepChar, but
this is optional. The default is ",". The quoting character can
be defined by the caller, but this is optional. The default is
'"'.
If the option -alternate is specified a slightly different syn-
tax is used to parse the input. This syntax is explained below,
in the section FORMAT.
::csv::split2matrix ?-alternate? m line {sepChar ,} {expand none}
The same as ::csv::split, but appends the resulting list as a
new row to the matrix m, using the method add row. The expansion
mode specified via expand determines how the command handles a
matrix with less columns than contained in line. The allowed
modes are:
none This is the default mode. In this mode it is the respon-
sibility of the caller to ensure that the matrix has
enough columns to contain the full line. If there are not
enough columns the list of values is silently truncated
at the end to fit.
empty In this mode the command expands an empty matrix to hold
all columns of the specified line, but goes no further.
The overall effect is that the first of a series of lines
determines the number of columns in the matrix and all
following lines are truncated to that size, as if mode
none was set.
auto In this mode the command expands the matrix as needed to
hold all columns contained in line. The overall effect is
that after adding a series of lines the matrix will have
enough columns to hold all columns of the longest line
encountered so far.
::csv::split2queue ?-alternate? q line {sepChar ,}
The same as ::csv::split, but appending the resulting list as a
single item to the queue q, using the method put.
::csv::writematrix m chan ?sepChar? ?delChar?
A wrapper around ::csv::join taking all rows in the matrix m and
writing them CSV formatted into the channel chan.
::csv::writequeue q chan ?sepChar? ?delChar?
A wrapper around ::csv::join taking all items in the queue q
(assumes that they are lists) and writing them CSV formatted
into the channel chan.
FORMAT
The format of regular CSV files is specified as
[1] Each record of a csv file (comma-separated values, as exported
e.g. by Excel) is a set of ASCII values separated by ",". For
other languages it may be ";" however, although this is not im-
portant for this case as the functions provided here allow any
separator character.
[2] If and only if a value contains itself the separator ",", then
it (the value) has to be put between "". If the value does not
contain the separator character then quoting is optional.
[3] If a value contains the character ", that character is repre-
sented by "".
[4] The output string "" represents the value ". In other words, it
is assumed that it was created through rule 3, and only this
rule, i.e. that the value was not quoted.
An alternate format definition mainly used by MS products specifies
that the output string "" is a representation of the empty string. In
other words, it is assumed that the output was generated out of the
empty string by quoting it (i.e. rule 2), and not through rule 3. This
is the only difference between the regular and the alternate format.
The alternate format is activated through specification of the option
-alternate to the various split commands.
EXAMPLE
Using the regular format the record
123,"123,521.2","Mary says ""Hello, I am Mary""",""
is parsed into the items
a) 123
b) 123,521.2
c) Mary says "Hello, I am Mary"
d) "
Using the alternate format the result is
a) 123
b) 123,521.2
c) Mary says "Hello, I am Mary"
d) (the empty string)
instead. As can be seen only item (d) is different, now the empty
string instead of a ".
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain
bugs and other problems. Please report such in the category csv of the
Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please also
report any ideas for enhancements you may have for either package
and/or documentation.
When proposing code changes, please provide unified diffs, i.e the out-
put of diff -u.
Note further that attachments are strongly preferred over inlined
patches. Attachments can be made by going to the Edit form of the
ticket immediately after its creation, and then using the left-most
button in the secondary navigation bar.
SEE ALSO
matrix, queue
KEYWORDS
csv, matrix, package, queue, tcllib
CATEGORY
Text processing
COPYRIGHT
Copyright (c) 2002-2015 Andreas Kupries <andreas_kupries@users.sourceforge.net>
tcllib 0.8.1 csv(3tcl)