What is the usage of php return

How to use php return: 1. Return an expression result through "return expression"; 2. Return a function expression through "return(expr)"; 3. Return directly or return nothing through return value.

#The operating environment of this article: Windows7 system, PHP7.1, Dell G3.

What is the usage of return in php?

Analysis of usage examples of return in php

First of all, it means return; return() is a language Structures, not functions, require parentheses only if the arguments contain expressions. Parentheses are usually not used when returning a variable, which can reduce the burden on PHP.

Basic usage:

a), return expression // Return an expression result

b), return(expr) // Function expression

c), return // Return directly, or return a null value

Note: It is best not to use return($val).

1. If return is executed, the content after the return statement will not be executed;

function add($a,$b){
 return $a+$b;
 return $a*$b;
}
$c = add(5,3);//得到的$c值可以用在程序的其他地方！
echo $c;

Output result: 8, only $a $b, $a*$b will be executed Not executed.

2. Return can be a function return value or a null value, depending on the specific usage, for example:

function test($a){
if($a>10){
 return "a>10";
}else{
 return "a<10";
}
$b=45;
$c=$b-$a;
echo $c;
}

In this example, when you call this function, Then given any number, it will return a string and the code:

$b=45;
$c=$b-$a;
echo $c;

will never be executed.

3. Regarding return calls.

a.php is as follows:

<?php
include("b.php");
echo "a";
?>

b.php is as follows:

<?php
echo "b";
return;
?>

Output result: ba.

a.php is as follows:

<?php
include("b.php");
echo "a";
?>

b.php is as follows:

<?php
echo "b";
exit; // 结束整个当前脚本
?>

Output result: a.

4. An important role of return: return value

Example 1:

function test(){
 $a=array(1,2);
 return $a;
}
$b=test();
print_r($b);

Example 2:

function test(){
 $a=array(1,2);
}
$b=test();
print_r($b);

Output result: Example 1 outputs normally, Example 2 output is empty. why? Because if you don't use return to return the value in the function rest(), there will only be a process in the function, but no result to rest(). Of course, there will be no value output when the function is called. Of course, we can also write print_r($b) into test() and print directly in the function, but many times, we will call operations outside the function, so we need to use return to return a value to the outside.

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