The while keyword

while is the statement that uses the EXPRESSION, called the condition, to loop through a block until the condition is true. It is the opposite of the until statement.

  while EXPRESSION

Examples

The code

$a = 5;
print $a++ while $a < 10;

prints the numbers 5 to 9 consecutively:

56789

The following two print statements

$i = 5;
print $i++ while $i <= 10;
$j = 5;
print $j++ until $j >  10;

return the same:

5678910
5678910