A Perl function which takes a substring of a string, returns it, and can replace it with another string.
substr($foo, offset);
returns the last part of the string $foo, beginning at the specified offset. Just like an array subscript, a negative offset counts from the end of the string.
By itself, substr($foo, offset) doesn't actually do anything. There are two ways of applying substr to do useful work.
- Use the return value; that is,
$bar = substr($foo, offset)
or
if (substr($foo, offset) =~ /bar/)
- Replace the substring with something else; that is,
substr($foo, offset) = "bar"
substr($foo, offset, length);
As above, but limits the string to a given number of characters.
substr($foo, offset, length, replacement);
Shorthand for 'substr($foo, offset, length) = replacement'
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