How to traverse array elements in PHP array learning? Brief analysis of 4 methods

In the previous article, we learned about the creation of PHP arrays. If you are interested, you can click on the link to view → "How to create and initialize one-dimensional arrays (detailed code explanation)". After creating the array, you need to perform operations. Traversing the array is a regular operation. So how to traverse the array elements in PHP? Today we will share with you 3 common methods.

This article will introduce 4 common methods through actual code examples: for loop, foreach statement, while loop each() list(), do-while loop array pointer.

Method 1: Use for loop statement

In the previous PHP loop series article "PHP loop learning three: How to use for loop In "Statement Traversing Arrays", we introduced the for loop and how to use this loop to traverse the array. This article will not introduce it in detail. Let’s take a closer look through the code example:

<?php
header("Content-type:text/html;charset=utf-8");
$array= array(2,"数学","梨子",3.14,"榴莲",12);
for ($i=0; $i < count($array); $i++) { 
    echo $array[$i] . "<br/>";
} 
?>

Output result:

2
数学
梨子
3.14
榴莲
12

Method 2: Use foreach loop statement

Similarly, in the previous PHP loop series article "PHP Loop Learning 4: How to use the foreach statement to traverse and modify array elements", we introduced the use of foreach loop Iterate over the 2 structures of the array. This article will not go into details. Let’s take a closer look at the code example:

<?php
header("Content-type:text/html;charset=utf-8");
$array= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
foreach ($array as $val){
    echo "值是：" . $val ;
    echo "<br/>";
}
echo "<br/>";
foreach ($array as $key => $value) { 
    echo "键名为：".$key."，键值为：".$value . "<br/>";
} 
?>

Output result:

## Method 3: Use while loop each() list()

each() function returns the current key value in the array and moves the array pointer forward. After each() is executed, the array pointer will stay at the next element in the array or at the last element when the end of the array is reached.

The list() function is used to assign values ​​to a set of variables in one operation.

while loop each() function list() function can traverse the array, let’s take a look at the code example below:

<?php
header("Content-type:text/html;charset=utf-8");
$array= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
while( list($key, $val) = each($array) ) {
    echo "$key => $val<br>";
}
?>

Output result:

Method 4: Use do-while loop next() key() current()

Every array in PHP has an internal Pointer, that is, array pointer; this pointer will point to an element in the array (the element is the current element of the array, and by default initially points to the first element in the array).

• next() function can return the value of the next element pointed to by the internal pointer of the array, and returns FALSE when there are no more elements.

• key() function is used to obtain the key name of the current element in the array.

• current() function returns the key value of the current element of the array.

Use do-while loop next() key() current() to traverse the array and obtain the key name and key value of the array element.

Let’s take a look at the code example below:

<?php
header("Content-type:text/html;charset=utf-8");
$array= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
do{
	 echo key($array)." => ".current($array)."<br>";
}while(next($array));
?>

Output result:

After the traversal is completed, the array pointer will point to the last one For array elements, we can use the reset() function to reset the array pointer and redirect the internal pointer in the array to the first element.

If you are not familiar with do-while loops, you can click to read "

PHP Loop Learning 2: How to use do-while loop statements" to learn about do-while loop statements.

Okay, that’s all. If you want to know anything else, you can click this. → →

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