PHP – Loop Types – Tutorialspoint

Loops in PHP are used to execute the same block of code a specific number of times. PHP supports tracing four types of loops.

for − loops through a block of code a

    specified number of times.

  • while − loops through a block of code as long as a specified condition is true.

  • do… while − loops through a block of code once, and then repeats the loop whenever a special condition is met.

  • foreach − loops through a block of code for each element of an array.

We will discuss about the continue and break keywords used to control the execution of loops

. The for loop statement

The

for statement is

used when you know how many times you want to execute an instruction or block of instructions.

for loop in Php

Syntax

for (initialization; condition; increase) { code to execute; }

The initializer is used to set the initial value for the number of loop iterations counter. Here a variable can be declared for this purpose and it is traditional to name it $i.

Example

The following example performs five iterations and changes the assigned value of two variables at each step of the loop −

<html> <body> <?php $a = 0; $b = 0; for( $i = 0; $i<5; $i++ ) { $a += 10; $b += 5; } echo (“At the end of loop a = $a and b = $b” ); ?> </body> </html>

This will produce the following result: At the

end of the loop a = 50 and b = 25 The while loop statement

The while statement

will execute a block of code as long as a test expression is true.

If the test expression is true, the code block will be executed. After the code is executed, the test expression will be evaluated again and the loop will continue until the test expression is found to be false.

for loop in PHP

Syntax

while (condition) { code to execute; }

Example

This example decreases a variable value at each iteration of the loop and increments the counter until it reaches 10 when the evaluation is false and the loop terminates.

<html> <body> <?php $i = 0; $num = 50; while( $i < 10) { $num-; $i++; } echo (“Loop stopped at i = $i and num = $num” ); ?> </body> </html>

This will produce the following result:

Loop stopped at i = 10 and num = 40

The do… while the loop statement

The do… While the instruction will execute a block of code at least once, it will repeat the loop whenever a condition is true.

Sintax

do { código a execute; } while (condition);

Example

The following example will increment the value

of i at least once, and continue to increment the variable i whenever it has a value less than 10 −

<html> <body> <?php $i = 0; $num = 0; do { $i++; } while( $i < 10 ); echo (“Loop stopped at i = $i”); ?> </body> </html>

This will produce the following result:

Loop stopped at i = 10 The

foreach loop statement The foreach statement

is used to loop through arrays. For each pass, the value of the current array element is mapped to $value and the array pointer is moved by one and the next pass will process the next element.

Foreach syntax

(array as value) { code to execute; }

Example

Try the following example to enumerate the values of an array.

<html> <body> <?php $array = array( 1, 2, 3, 4, 5); foreach( $array as $value ) { echo “Value is $value <br />”; } ?> </body> </html>

This will produce the following result:

The value is 1 The value is 2 The value is 3 The value is 4 The value is 5 The break statement The

PHP break keyword is used to terminate the execution of a loop prematurely

.

The break statement is located inside the instruction block. It gives you full control and whenever you want to get out of the loop you can exit. After exiting a loop, an immediate instruction to the loop will be executed.

<img src=”https://www.tutorialspoint.com/php/images/cpp_break_statement.jpg” alt=”PHP Break Statement” />

Example

In the following

example, the condition test becomes true when the counter value reaches 3 and the loop terminates.

<html> <body> <?php $i = 0; while( $i < 10) { $i++; if( $i == 3 )break; } echo (“Loop stopped at i = $i”); ?> </body> </html>

This will produce the following result:

loop stopped at i = 3 The

continue statement The

PHP continue keyword is used to stop the current iteration of a loop, but does not end the loop

. Like the break statement, the

continue statement is located inside the instruction block that contains the code that executes the loop, preceded by a conditional test. For the pass finding continue statement, the rest of the loop code is ignored and the next pass begins.

<img src=”https://www.tutorialspoint.com/php/images/cpp_continue_statement.jpg” alt=”PHP Continue Declaration” />

Example

In the example below, the loop prints the array value,

but for which condition it becomes true, it simply omits the code and prints the next value.

<html> <body> <?php $array = array( 1, 2, 3, 4, 5); foreach( $array as $value ) { if( $value == 3 )continue; echo “Value is $value <br />”; } ?> </body> </html>

This will produce the following result: the

value is 1 The value is 2 The value is 4 The value is 5

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