PDL::Char--3pm

Char(3pm)             User Contributed Perl Documentation            Char(3pm)



NAME
       PDL::Char -- PDL subclass which allows reading and writing of
       fixed-length character strings as byte PDLs

SYNOPSIS
        use PDL;
        use PDL::Char;

        my $pchar = PDL::Char->new( [['abc', 'def', 'ghi'],['jkl', 'mno', 'pqr']] );

        $pchar->setstr(1,0,'foo');

        print $pchar; # 'string' bound to "", perl stringify function
        # Prints:
        # [
        #  ['abc' 'foo' 'ghi']
        #  ['jkl' 'mno' 'pqr']
        # ]

        print $pchar->atstr(2,0);
        # Prints:
        # ghi

DESCRIPTION
       This subclass of PDL allows one to manipulate PDLs of 'byte' type as if
       they were made of fixed length strings, not just numbers.

       This type of behavior is useful when you want to work with charactar
       grids.  The indexing is done on a string level and not a character
       level for the 'setstr' and 'atstr' commands.

       This module is in particular useful for writing NetCDF files that
       include character data using the PDL::NetCDF module.

FUNCTIONS
       new

       Function to create a byte PDL from a string, list of strings, list of
       list of strings, etc.

        # create a new PDL::Char from a perl array of strings
        $strpdl = PDL::Char->new( ['abc', 'def', 'ghij'] );

        # Convert a PDL of type 'byte' to a PDL::Char
        $strpdl1 = PDL::Char->new (sequence (byte, 4, 5)+99);

        $pdlchar3d = PDL::Char->new([['abc','def','ghi'],['jkl', 'mno', 'pqr']]);

       string

       Function to print a character PDL (created by 'char') in a pretty for-
       mat.

        $char = PDL::Char->new( [['abc', 'def', 'ghi'], ['jkl', 'mno', 'pqr']] );
        print $char; # 'string' bound to "", perl stringify function
        # Prints:
        # [
        #  ['abc' 'def' 'ghi']
        #  ['jkl' 'mno' 'pqr']
        # ]

        # 'string' is overloaded to the "" operator, so:
        # print $char;
        # should have the same effect.

       setstr

       Function to set one string value in a character PDL.  The input posi-
       tion is the position of the string, not a character in the string.  The
       first dimension is assumed to be the length of the string.

       The input string will be null-padded if the string is shorter than the
       first dimension of the PDL.  It will be truncated if it is longer.

        $char = PDL::Char->new( [['abc', 'def', 'ghi'], ['jkl', 'mno', 'pqr']] );
        $char->setstr(0,1, 'foobar');
        print $char; # 'string' bound to "", perl stringify function
        # Prints:
        # [
        #  ['abc' 'def' 'ghi']
        #  ['foo' 'mno' 'pqr']
        # ]
        $char->setstr(2,1, 'f');
        print $char; # 'string' bound to "", perl stringify function
        # Prints:
        # [
        #  ['abc' 'def' 'ghi']
        #  ['foo' 'mno' 'f']      -> note that this 'f' is stored "f\0\0"
        # ]

       atstr

       Function to fetch one string value from a PDL::Char type PDL, given a
       position within the PDL.  The input position of the string, not a char-
       acter in the string.  The length of the input string is the implied
       first dimension.

        $char = PDL::Char->new( [['abc', 'def', 'ghi'], ['jkl', 'mno', 'pqr']] );
        print $char->atstr(0,1);
        # Prints:
        # jkl



perl v5.8.8                       2002-05-21                         Char(3pm)