PHP control statement Loop

Loop

When writing code, you often need to run the same code block multiple times. You can use loop statements in the code to complete this task. In PHP, we can use the following loop statement:

While

The code block is executed cyclically as long as the specified condition is true.

Do... while

Execute a code block first, and then repeat the loop when the specified condition is set.

For

The number of times the code block is executed cyclically.

Foreach

Loop code Blocks Based on each element in the array

While statement

As long as the specified condition is true, the while statement repeats the code block.

Syntax

while (condition)code to be executed;

Example

The following example demonstrates a loop. As long as the variable I is less than or equal to 5, the code will continue to run cyclically. Every cycle of a loop increases by 1:

＜?php $i=1;while($i<=5) { echo "The number is " . $i . " "; $i++; }?＞

Do... while statement

The do... while statement will execute the code at least once-then, as long as the condition is true, the loop will be repeated.

Syntax

do{code to be executed;}while (condition);

Example

In the following example, the I value is accumulated once. Then, as long as the I is less than 5, it will continue to accumulate:

For statement

If you have determined the number of times the code block is repeated, you can use the for statement.

Syntax

for (initialization; condition; increment){ code to be executed;}

Do... while statement

The do... while statement will execute the code at least once-then, as long as the condition is true, the loop will be repeated.

Syntax

do{code to be executed;}while (condition);

Example

In the following example, the I value is accumulated once. Then, as long as the I is less than 5, it will continue to accumulate:

＜?php $i=0;do { $i++; echo "The number is " . $i . " "; }while ($i<5);?＞

For statement

If you have determined the number of times the code block is repeated, you can use the for statement.

Syntax

for (initialization; condition; increment){ code to be executed;}

Note:The for statement has three parameters. The first parameter initializes the variable, the second parameter saves the condition, and the third parameter contains the increment required for the execution cycle. If the initialization or increment parameter contains multiple variables, separate them with commas. The condition must be calculated as true or false.

Example

In the following example, the text "Hello World! "Display 5 times:

＜?phpfor ($i=1; $i<=5; $i++){ echo "Hello World! ";}?＞

Foreach statement

The foreach statement is used to traverse arrays cyclically.

For each loop, the value of the current array element is assigned to the value variable (the array pointer is moved one by one), and so on.

Syntax

foreach (array as value){ code to be executed;}

Example

The following example demonstrates a loop that outputs the value of a given array:

＜?php$arr=array("one", "two", "three");foreach ($arr as $value){ echo "Value: " . $value . " ";}?＞