Learning Perl, Fourth Edition

Strings

Strings are sequences of characters (like hello). Strings may contain any combination of any characters.^[40] The shortest possible string has no characters. The longest string fills all of your available memory, though you wouldn’t be able to do much with that. This is in accordance with the principle of “no built-in limits” that Perl follows at every opportunity. Typical strings are printable sequences of letters, digits, and punctuation in the ASCII 32 to ASCII 126 range. However, the ability to have any character in a string means you can create, scan, and manipulate raw binary data as strings and that is something with which many other utilities would have great difficulty. For example, you could update a graphical image or compiled program by reading it into a Perl string, making the change, and writing the result back out.

Like numbers, strings have a literal representation, which is the way you represent the string in a Perl program. Literal strings come in two different flavors: single-quoted string literals and double-quoted string literals.

Single-Quoted String Literals

A single-quoted string literal is a sequence of characters enclosed in single quotes. The single quotes are not part of the string itself but are there to let Perl identify the beginning and the ending of the string. Any character other than a single quote or a backslash between the quote marks (including newline characters, if the string continues onto successive lines) stands for itself inside a ...