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PHP - For Loop



The for loop executes a set of statements in each iteration. Whenever, number of iteration is known, for loop is preferred over while loop.

Syntax

for(initialization(s); condition(s); counter_update(s);){
  statements;
} 

  • Initialization(s): Variable(s) is initialized in this section and executed for one time only.
  • Condition(s): Condition(s) is defined in this section and executed at the start of loop everytime.
  • Counter Update(s): Loop counter(s) is updated in this section and executed at the end of loop everytime.

Flow Diagram:

php For Loop

Example:

In the example below, the program continue to print variable called i from value 1 to 5. After that, it exits from the for loop.

<?php
for ($i = 1; $i <= 5; $i++) {
  echo $i."\n"; 
}
?>

The output of the above code will be:

1
2
3
4
5

Example

Multiple initializations, condition checks and loop counter updates can be performed in a single for loop. In the example below, two variable called i and j are initialized, multiple conditions are checked and multiple variables are updated in a single for loop.

<?php
for ($i = 1, $j = 100;  $i <= 5 || $j <= 800;  $i++, $j = $j + 100){
  echo "i=".$i.", j=".$j."\n"; 
}
?>

The output of the above code will be:

i=1, j=100
i=2, j=200
i=3, j=300
i=4, j=400
i=5, j=500
i=6, j=600
i=7, j=700
i=8, j=800

5