Multiple conditions

At times you may have more than one condition that you want satisfied in order to execute a series of statements. For this you can specify the conditions as follows:

my $age = 22;
if ($age < 30 && $age > 10) {
   print qq{You're young, but no spring chicken\n};
}

In this example, both $age < 30 and $age > 10 must be satisfied in order that the specified statement be executed. There are also occasions when you want either one condition or another to be true to carry out some operation. This can be done as

my $age = 22;
if ($age < 13 || $age > 19) {
   print qq{You're not a teenager\n};
}

Here, either $age < 13 or $age > 19 must be true in order that the specified statements be executed. If you have multiple such conditions to test for, it is wise to group them using brackets:

my $age = 22;
my $gender = 'female';
if ($gender eq 'female' && ($age < 13 || $age > 19) ) {
   print qq{You're a female, but not a teenager\n};
}

Sometimes, it is more natural to express a condition as the negation of another condition. For this, you can use the ! operator:

my $age = 22;
my $gender = 'female';
if ($gender eq 'female' && ! ($age > 12 && $age < 20) ) {
   print qq{You're a female, but not a teenager\n};
}

Perl provides an (almost) alternate syntax for the &&, ||, and ! operators:

• and for &&
• or for ||
• not for !

These are not exact equivalences (differences arise in how tightly the operators ``bind'' to the expression to the right of the operator), but for simple purposes you can use either.