Re: Algorithm help for unique string searching/counting within an array.

Paul Van Delst <Paul.vanDelst@xxxxxxxx> wrote:

I want to be able to search an array of strings (with many repeated elements) so I can
count the unique elements.

Are you sure you want to use Fortran for this? Languages like Perl or
awk have built-in arrays with strings as subscripts. Perl calls
them "hashes".

Here's a short Perl program (for illustration), which assumes that
all the strings are in separate lines.

#! /usr/bin/perl

while(<>) { # Loop over all entries in the array, putting values into $_ .
chomp; # Eat newlines
$string{$_}++; # Increment the hash element with the subscript $_ by
# one, creating the element if necessary.
}

print scalar(keys(%string)),"\n"; # Count the number of keys to the hash.

Maybe somebody has implemented hash tables in Fortran as a module
that you could reuse.
.

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