Question

I am new to Perl, by the way. I have a Perl script that needs to count the number of times a string appears in the file. The script gets the word from the file itself.

I need it to grab the first word in the file and then search the rest of the file to see if it is repeated anywhere else. If it is repeated I need it to return the amount of times it was repeated. If it was not repeated, it can return 0. I need it to then get the next word in the file and check this again.

I will grab the first word from the file, search the file for repeats of that word, grab the second word from
the file, search the file for repeats of that word, grab the third word from the file, search the file for repeats of that word.

So far I have a while loop that is grabbing each word I need, but I do not know how to get it to search for repeats without resetting the position of my current line. So how do I do this? Any ideas or suggestions are greatly appreciated! Thanks in advance!

while (<theFile>) {
    my $line1 = $_;
    my $startHere = rindex($line1, ",");
    my $theName = substr($line1, $startHere + 1, length($line1) - $startHere);
    #print "the name: ".$theName."\n";
}

Answer 1

Use a hashtable;

my %wordcount = ();

while(my $line = <theFile>)
{
    chomp($line);
    my @words = split(' ', $line);
    foreach my $word(@words)
    {
        $wordCount{$word} += 1;
    }
}

# output
foreach my $key(keys %wordCount)
{
    print "Word: $key Repeat_Count: " . ($wordCount{$key} - 1) . "\n";
}

The $wordCount{$key} - 1 in the output accounts for the first time a word was seen; Words that only apprear once in the file will have a count of 0

Unless this is actually homework and/or you have to achieve the results in the specific manor you describe, this is going to be FAR more efficient.

Edit: From your comment below:

Each word i am searching for is not “the first word” it is a certain word on the line. Basically i have a csv file and i am skipping to the third value and searching for repeats of it.

I would still use this approach. What you would want to do is:

• split on , since this is a CSV file
• Pull out the 3rd word in the array on each line and store the words you are interested in in their own hash table
• At the end, iterate through the “search word” hash table, and pull out the counts from the wordcount table

So:

my @words = split(',', $line);
$searchTable{@words[2]} = 1;

...

foreach my $key(keys %searchTable)
{
    print "Word: $key Repeat_Count: " . ($wordCount{$key} - 1) . "\n";
}

you’ll have to adjust according to what rules you have around counting words that repeat in the third column. You could just remove them from @words before the loop that inserts into your wordCount hash.