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 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, 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.