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Home: Perl Programming Help: Beginner:
Strings and Columns?



Mar 24, 2000, 6:35 AM

Post #1 of 2 (1897 views)
Strings and Columns? Can't Post

How can I get the number of strigs and columns of a two dimensional array?
I'm gonna use it in a FOR!


Mar 24, 2000, 7:14 AM

Post #2 of 2 (1897 views)
Re: Strings and Columns? [In reply to] Can't Post

I think you're thinking in a C kind of loop. In Perl, you don't need to iterate over an array by element number, you can iterate over the actual elements:

<BLOCKQUOTE><font size="1" face="Arial,Helvetica,sans serif">code:</font><HR>

# what a C programmer might do...
for ($i = 0; $i = $#array; $i++) {

# what a Perl programmer would do...
for (@array) {

Read about for (or foreach) loops in the perlsyn documentation (comes with Perl, and is also on this web site). To work with two dimensional arrays, do something like:

<BLOCKQUOTE><font size="1" face="Arial,Helvetica,sans serif">code:</font><HR>

for $out (@array) {
for $in (@{ $out }) {

To get the number of elements in an array, evaluate @array in scalar context:

<BLOCKQUOTE><font size="1" face="Arial,Helvetica,sans serif">code:</font><HR>

$size = @foo;

To get the LAST INDEX of an array (which is the number of elements, minus one), use the $#array variable:

<BLOCKQUOTE><font size="1" face="Arial,Helvetica,sans serif">code:</font><HR>

$lastindex = $#bar;

Arrays are discussed in the perldata documentation. Multidimensional arrays are discussed in perlref, perllol, and perldsc. The perlreftut documentation (which comes with either 5.005_03 or the newest Perl, 5.6) might be good for you, too. If that's not on this site, perhaps it can be gotten from the web site.


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