Tips for learning PHP arrays and using functions to insert elements (1)

In the previous article, we introduced two alternative methods of creating arrays - filling method to create new arrays. If you are interested, you can click on the link to read → "PHP Array Learning: How to Create a Filling Method Array》. Let me introduce to you how to insert new elements into PHP arrays. Let’s take a look.

There are multiple functions built into PHP that can add new elements to the array, such as array_unshift(), array_push(), array_pad(), array_splice(), etc. This article will first introduce you to two of the functions, array_unshift() and array_push(), and I will introduce you to the next two functions in the next article.

The following is a code example to introduce in detail how the array_unshift() and array_push() functions insert new elements.

1. The array_unshift() function inserts new elements into the array

array_unshift($array,$value1,$value2...) The function can insert one or more new elements (key values) at the beginning of the array.

Let’s take a closer look at the following example:

<?php
$arr=array(10,12,20);
array_unshift($arr,8,"9");
var_dump($arr);
?>

array_unshift($arr,8,9)It can be seen that two characters are inserted at the beginning of the $arr array new elements: the value "8" and the string "9", so the output result is:

array_unshift() The function will not maintain the original numerical index relationship, but will delete all numerical key names and reassign them, that is, count again from 0; but all string key names will remain unchanged.

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array("a"=>"red","b"=>"green",3=>"pink");
echo "原来的数组：";
var_dump($arr);
array_unshift($arr,"blue");
echo "在开头插入一个新元素后：";
var_dump($arr);
?>

Output result:

2. The array_push() function inserts new elements into the array

array_push($array,$value1,$value2...)The function can insert one or more elements (key values) at the end of the array.

Let’s take a closer look at the following example:

<?php
$arr=array(10,12,20);
array_push($arr,8,"9",3.14);
var_dump($arr);
?>

array_push($arr,8,"9",3.14)It can be seen that in the $arr array Insert 3 elements at the end: integer "8", string "9" and floating point number "3.14", so the output result is:

The array_push() function is different from the array_unshift() function. It does not reset the numerical key name, but counts based on the original numerical key name.

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array("a"=>"red","b"=>"green",3=>"pink");
array_push($arr,8,"9",3.14);
var_dump($arr);
?>

Output result:

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

Finally, I would like to recommend a free video tutorial on PHP arrays: PHP function array array function video explanation, come and learn!

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