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PHP function static variable implements the specified number of iterations

小云云
小云云Original
2018-03-20 09:43:181312browse

This article mainly introduces the method of using function static variables in PHP to specify the number of iterations, and analyzes the relevant operating skills of PHP static variable data storage in the form of examples. Friends in need can refer to it,

The example in this article describes how PHP uses function static variables to specify the number of iterations. Share it with everyone for your reference, the details are as follows:

In PHP, in addition to the static member attributes of the class, you can also use static to define static variables in functions. This makes it easy to complete function iteration.

Example 1:


<?php
function Test()
{
  $a = 0;
  echo $a;
  $a++;
}
?>

In the above example, every time the Test function is called, a is reassigned to 0, Because once this function is exited, the variable a will be reassigned to 0, because once this function is exited, the variable a will no longer exist. To complete the iteration, you need to write a counting function that will not lose this count value. You must define the variable $a as static:


<?php
function test()
{
  static $a = 0;
  echo $a;
  $a++;
}
?>

In this way, $a only It is assigned on the first call, incremented by 1 on each subsequent call, and will not be overridden.

In this way, you can use this feature to iterate a specified number of times for an operation:

Example 2: (Get the result after popping 5 elements out of an array)


$arr = range(1,10,1);
function test($arr)
{
  static $count=0;
  array_pop($arr);
  $count++;
  if ($count < 5) {
    test($arr);
  }else{
    var_dump($arr);exit;
  }
}
test($arr);

Running results:


array(5) {
 [0]=>
 int(1)
 [1]=>
 int(2)
 [2]=>
 int(3)
 [3]=>
 int(4)
 [4]=>
 int(5)
}

Related recommendations:

About PHP aggregation Usage sharing of the iterator interface IteratorAggregate

Adjust JavaScript abstraction iteration scheme

Detailed examples of five iteration methods for JavaScript arrays

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