home | O'Reilly's CD bookshelfs | FreeBSD | Linux | Cisco | Cisco Exam  

Book Home Programming PerlSearch this book

3.12. Equality Operators

The equality operators listed in Table 3-6 are much like the relational operators.

Table 3.6. Equality Operators

Numeric String Meaning
== eq Equal to
!= ne Not equal to
<=> cmp Comparison, with signed result

The equal and not-equal operators return 1 for true and "" for false (just as the relational operators do). The <=> and cmp operators return -1 if the left operand is less than the right operand, 0 if they are equal, and +1 if the left operand is greater than the right. Although the equality operators appear to be similar to the relational operators, they do have a lower precedence level, so $a < $b <=> $c < $d is syntactically valid.

For reasons that are apparent to anyone who has seen Star Wars, the <=> operator is known as the "spaceship" operator.

Library Navigation Links

Copyright © 2001 O'Reilly & Associates. All rights reserved.