RE: Count how often a certain element occurs in an array

[Haimov, Eugene]

Title: Message

# Unrealistic to store 400000 names in an array.

# A more practical solution may look like this:

 

$FileName = '....your file name here....';

$ResultFile = '...your output file here....';

open ( INPUT, $FileName ) or die "Cannot open [$FileName]: $!\n";

open ( OUTPUT, ">$ResultFile" ) or die "Cannot open: [$ResultFile] $!\n";

my %hash;

while ($Line =<INPUT>)

{

    chomp $Line;

    $hash{$Line}++;

}

close INPUT;

 

for $key (keys %hash) {

    print OUTPUT "Name: $key count = $hash{$key}\n";

}

close OUTPUT;

 

Eugene Hiamov

-----Original Message-----
From: Mumper, Jay [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 06, 2002 11:10 AM
To: 'Heiko Nieke'; [EMAIL PROTECTED]
Subject: RE: Count how often a certain element occurs in an array

Something like

 

my %hash;

for (my $i=0;$i<@array;$i++) {

    if (!$hash{$array[$i]}) {

        $hash{$array[$i]} = 1;

    } else {

        $hash{$array[$i]}++;

    }

}

 

foreach $key (keys %hash) {

    print "Name: $key count = $hash{$key}\n";

}

 

-- Jay Mumper

 

-----Original Message-----
From: Heiko Nieke [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 06, 2002 11:03 AM
To: [EMAIL PROTECTED]
Subject: Count how often a certain element occurs in an array

Hi,

It might be a silly question, but I am new to perl and I need to solve the following problem

- I have a list with approx. 400000 names

for example:
Christian
Sally
Christian
Klaus
....

Now I need to know how often each name appears in the list. Could anybody help me doing this with a perl script?

Thanks
Heiko