Sams Teach Yourself Perl in 21 Days, Second Edition

Assignment Operators

Yesterday, we discussed the basic assignment operator, =, which assigns a value to a variable. One common use of assignment is an operation to change the value of a variable based on the current value of that variable, such as:

$inc = $inc + 100;

This does exactly what you'd expect; it gets the value of $inc, adds 100 to it, and then stores the result back into $inc. This sort of operation is so common that there is a shorthand assignment operator to do just that. The variable reference goes on the left side, and the amount to change it on the right, like this:

$inc += 100;

Perl supports shorthand assignments for each of the arithmetic operators, for string operators I haven't described yet, and even for && and ||.