Assignment Operators

Get introduced to the functionality of the assignment and the combined assignment operator in this lesson.

We'll cover the following

Basic assignment

Perl allows you to do the basic arithmetic assignment by using the = operator.

The above statement results in $a having the value “hello”. The result of an assignment expression is the value being assigned. Note that a single equal sign = is NOT for comparison!

Example

Run the following code to see what happens:

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$a = 3;
print "\$a = ".$a;    #prints $a = 3
$b = ($a = 5);        #assigns 5 to $a and then assigns the value of $a to $b
print "\n\$a = ".$a;  #prints $a = 5
print "\n\$b = ".$b;  #prints $b = 5

Explanation

  1. Line 1 assigns 3 to $a.
  2. Line 3 assigns 5 to $a, and later assigns the result of the expression in parentheses ($a=5) to $b.

Thus, both $a and $b now have the value 5.

Combined assignment

The combined assignment operators are a shortcut for an operation on some variable and subsequently assigning this new value to that variable.

Example

Run the code below to see how combined assignment works:

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$a = 1;                 # basic assignment
print (($a += 2)."\n"); # read as '$a = $a + 2'; $a now is (1 + 2) => 3
print (($a -= 1)."\n"); # $a now is (3 - 1) => 2
print (($a *= 8)."\n"); # $a now is (2 * 8) => 16
print (($a /= 2)."\n"); # $a now is (16 / 2) => 8
print (($a %= 5)."\n"); # $a now is (8 % 5) => 3 (modulus or remainder)
print (($a **= $a)."\n"); # $a now is (3 ^ 3) => 27 (Exponent)

Difference between = and == operator

We use = to assign value to the variable:

$variable = 10;

while == is used to compare the value that variable contains:

$variable = 10;
if(variable == 10) # returns true.