There are a number of ways, with varying efficiency. If you want a count of a certain single character (X) within a string, you can use the tr/// function like so:
$string = "ThisXlineXhasXsomeXx'sXinXit";
$count = ($string =~ tr/X//);
print "There are $count X characters in the string";This is fine if you are just looking for a single character. However,
if you are trying to count multiple character substrings within a
larger string, tr/// won't work. What you can do is wrap a while()
loop around a global pattern match. For example, let's count negative
integers:
$string = "-9 55 48 -2 23 -76 4 14 -44";
while ($string =~ /-\d+/g) { $count++ }
print "There are $count negative numbers in the string";Another version uses a global match in list context, then assigns the
result to a scalar, producing a count of the number of matches.
$count = () = $string =~ /-\d+/g;