What is Loops?
Loops are used to execute the same block of code again and again, as long as a certain condition is met. The basic idea behind a loop is to automate the repetitive tasks within a program to save the time and effort. PHP supports four different types of loops.
Loops are used to execute the same block of code again and again, as long as a certain condition is true.
Different Types of Loops in PHP
- while — loops through a block of code as long as the condition specified evaluates to true.
- do…while — the block of code executed once and then condition is evaluated. If the condition is true the statement is repeated as long as the specified condition is true.
- for — loops through a block of code until the counter reaches a specified number.
- foreach — loops through a block of code for each element in an array.
PHP while Loop
The while statement will loops through a block of code as long as the condition specified in the while statement evaluate to true.
Syntax
while (condition is true) {
code to be executed;
}
This Example of Increment
Example:-
This Example of Decrement
PHP do…while Loop
The do-while
loop is a variant of while loop, which evaluates the condition at the end of each loop iteration. With a do-while
loop the block of code executed once, and then the condition is evaluated, if the condition is true, the statement is repeated as long as the specified condition evaluated to is true.
Syntax
do { code to be executed; } while (condition is true); The following example define a loop that starts with$a=1
. It will then increase$a
with 1, and print the output. Then the condition is evaluated, and the loop will continue to run as long as $a is less than, or equal to 10.
Examples
This Example of Increment
This Example of Decrement
PHP for Loop
The for
loop repeats a block of code as long as a certain condition is met. It is typically used to execute a block of code for certain number of times.
Syntax
for(initialization; condition; increment){
// Code to be executed
}
The parameters of for
loop have following meanings:
initialization
— it is used to initialize the counter variables, and evaluated once unconditionally before the first execution of the body of the loop.condition
— in the beginning of each iteration, condition is evaluated. If it evaluates totrue
, the loop continues and the nested statements are executed. If it evaluates tofalse
, the execution of the loop ends.increment
— it updates the loop counter with a new value. It is evaluate at the end of each iteration.
The example below defines a loop that starts with $a=1
. The loop will continue until $a
is less than, or equal to 10. The variable $a
will increase by 1 each time the loop runs:
Example:-
PHP foreach Loop
The foreach
loop is used to iterate over arrays.
Syntax:-
foreach ($array as$value) {
code to be executed;
}
The following example demonstrates a loop that will print the values of the given array:
Example:-
There is one more syntax of foreach
loop, which is extension of the first.
Syntax:-
foreach($array as $key => $value){ // Code to be executed }
Example:-
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