How to get certain values ​​in an array in php

3 ways to obtain: 1. Use "$array name[subscript]" to obtain one by one. 2. Use array_slice() to get several consecutive element values, the syntax is "array_slice(array, starting position, number)" or "array_slice(array, - position)". 3. Use array_splice() to get several consecutive elements Element value, syntax "array_splice(array, starting position, number)" or "array_splice(array, - position)".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

php provides a variety of methods to get certain values ​​​​in the array, let’s take a look below.

Situation 1: Get several discontinuous element values

In PHP, you can use the "$array name[subscript]" statement to get them one by one.

"$array name[subscript]" can access an element of the specified subscript in the array

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
var_dump($arr);
echo "获取第1位的元素：".$arr[0]."<br>";
echo "获取第3位的元素：".$arr[2]."<br>";
echo "获取第6位的元素：".$arr[5]."<br>";
?>

Case 2: Get several consecutive element values

Method 1. Use array_slice() function

array_slice() function is PHP A function provided to intercept an array and extract a fragment from the array.

array_slice($array,$start,$length,$preserve)

This function supports 2 required parameters: $array and $start, two omitted parameters $length and $preserve.

Parameter $array does not need to be introduced. , the parameter $start is used to specify the position (subscript) to start interception, and the parameter $length indicates the interception length (if omitted, it will intercept from the specified subscript to the end of the array ).

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
var_dump($arr); 

echo "获取第3位开始的全部数组元素：";
$result = array_slice($arr,2); //截取从下标2开始的全部数组元素
var_dump($result);

echo "获取第2位和第3位：";
$result = array_slice($arr,1,2); //截取从下标1开始的两个元素
var_dump($result);

?>

The output result is:

The parameter $start can be a negative number, then the distance from the end of $array -Start at the position of (that is, position from the right side of the array to the left according to the absolute value), and intercept from the back to the front. For example, -2 means starting from the penultimate element of the array .

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
var_dump($arr); 

echo "获取最后两位元素：";
$result = array_slice($arr,-2);
var_dump($result);

?>

The output result is:

2. Use array_splice() function

array_splice() function When deleting some elements of the array, the deleted elements will be formed into a new array, and then the new array will be returned.

Use array_splice($array,$start,$length)The function can intercept an array fragment of the specified length (the value of $length) based on the array subscript (the value of $start).

Let’s look at the following small example:

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
var_dump($arr); 

echo "获取第2位和第3位：";
$result = array_splice($arr,1,2); //截取从下标1开始的两个元素
var_dump($result);

?>

The output result is:

$startIf the value is negative, get the last N elements

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array("香蕉","苹果","梨子","橙子","橘子","榴莲");
var_dump($arr); 

echo "获取最后3位元素：";
$result = array_splice($arr,-3); 
var_dump($result);

?>

Note: array_splice() function will change the original array.

Recommended learning: "PHP Video Tutorial"

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