FAQ 6.15 How can I print out a word-frequency or line-frequency summary?


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This is an excerpt from the latest version perlfaq6.pod, which
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6.15: How can I print out a word-frequency or line-frequency summary?

To do this, you have to parse out each word in the input stream. We'll
pretend that by word you mean chunk of alphabetics, hyphens, or
apostrophes, rather than the non-whitespace chunk idea of a word given
in the previous question:

while (<>) {
while ( /(\b[^\W_\d][\w'-]+\b)/g ) { # misses "`sheep'"

while ( ($word, $count) = each %seen ) {
print "$count $word\n";

If you wanted to do the same thing for lines, you wouldn't need a
regular expression:

while (<>) {

while ( ($line, $count) = each %seen ) {
print "$count $line";

If you want these output in a sorted order, see perlfaq4: "How do I sort
a hash (optionally by value instead of key)?".


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