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csv(3tcl) CSV processing csv(3tcl) 





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?










DESCRIPTION


The csv package provides commands to manipulate information
    in CSV FORMAT (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 containing these
      values. The separator character can be defined by the caller, but this is
      optional. The default is ",". The quoting 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 format
      containing these values. The separator character can be defined 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 surrounded 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 containing these
      values. The separator character can be defined 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 surrounded by
      the delChar instead. Each row of the matrix 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::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 expand argument see
      ::csv::split2matrix.

  
::csv::read2queue ?-alternate? chan q {sepChar
    ,}

  
A wrapper around ::csv::split2queue (see below) reading
      CSV-formatted 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 contained
      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 syntax 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:







  

  
This is the default mode. In this mode it is the responsibility 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.

  

  
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.

  

  
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 important
      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 represented 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 output 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>








  

    0.8.1
    tcllib