Comparison Operators

Common Operators << Comparison Operators >> Logical Operators

Comparison operators are used for decision making. They let you compare one thing to another.

<
>
==
<=
>=
!=
<=>

less than
greater than
equal to
less than OR equal to
greater than OR equal to
not equal to
comparison

Most of the above comparisons produce a true/false value except the last one. Here is a quick example to show how it works :

$result = $a<=>5;

$result equals 1 if $a is greater than 5.
$result equals -1 if $a is less than 5.
$result equals 0 if $a is equal to 5.

Here is a larger example to show comparisons in action :

#!/usr/bin/perl
print "Content-type: text/html\n\n;
$x=5;
$y=15.5;
$z=.05;

$a=$x<6;
print "a equals $a ";

$b=$x>6;
print "b equals $b ";

$c=$x>=5;
print "c equals $c ";

$d=$x>=5;
print "d equals $d ";

$e=$x==5;
print "e equals $e ";

$f=$x!=5;
print "f equals $f ";

$g=$x<=>6;
print "g equals $g";

Strings (values containing letters and such) also have comparison operators, they just look a bit different than the number ones above. The operator takes the first character of each string and compares them.

lt
gt
eq
le
ge
ne
cmp

less than
greater than
equal to
less than or equal to
greater than or equal to
not equal to
comparison

Some sample results :

"dog" lt "cat"
"345" gt "62"
"dog" le "cat"
"dog" ge "cat"
"dog" eq "cat"
"dog" ne "cat"
"dog" cmp "cat"

false.
false.
false.
true.
false.
true.
1

c is less than d.
3 is less than 6.
c is still less than d.
d is greater than c.
The two are not equal.
They are not equal.
d is greater than c.

Common Operators << Comparison Operators >> Logical Operators

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