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Perl - Operators

Numeric and String Operators

There are many operators in Perl, here are a few that are commonly used:

Operator	Description	Example	Result
.	String concatenate	'ACTGA' . 'GCG'	ACTGAGCG
=	Assignment	$a = 'ATP'	$a variable is storing 'ATP'
+	Addition	4 + 2	6
-	Subtraction	7 - 2	5
-	Negation	-3	-3
!	Not	!1	0
*	Multiplication	5 * 2	10
/	Division	7 / 2	3.5
%	Modulus	3%2	1
**	Exponentiation	6**2	36
x	Repetition	'A' x 7	AAAAAAA

Logical Operators

The logical operators evaluate from left to right testing the truth of the statement.

$a && $b	and	$a if $a is false, $b otherwise
$a || $b	or	$a if $a is true, $b otherwise

Comparison Operators

These operators compare strings or numbers, returning TRUE (1) or FALSE (0):

Numeric Comparison			String Comparison
3 == 2	0	equal to	'Santa' eq 'Claus'	0	equal to
3 != 2	1	not equal to	'Santa' ne 'Claus'	1	not equal to
3 < 2	0	less than	'Santa' lt 'Claus'	0	less than
3 > 2	1	greater than	'Santa' gt 'Claus'	1	greater than
3 <= 2	0	less or equal	'Santa' le 'Claus'	0	less than or equal
3 >= 2	1	greater than or equal	'Santa' ge 'Claus'	1	greater than or equal
3 <=> 2	1	compare	'Santa' cmp 'Claus'	1	compare

The string comparison operators compare the alphabetical order.

The numeric comparison operators are quite self explanatory except probably the last numeric one, which may need an example:

3 <=> 2

if left side of the operator is greater than the right side, it returns 1
if both sides are equal, 0
if right side of the operator is greater than the left side, it returns -1

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