PHP has several array initialization methods

3 methods: 1. Use "[]" to assign values ​​to elements individually, the syntax is "$array variable name [subscript] = value;"; 2. Use "[]" to initialize all elements together, Syntax "$array variable name = [key value list];"; 3. Use array() to initialize all elements together, syntax "$array variable name = array (key value list)".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

3 methods of php array initialization

Method 1: Assign values ​​to the elements in the array individually

$数组变量名[下标] = 值;

The subscript (index value) can be a string or an integer, and the subscript needs to be wrapped with [].

<?php
header("Content-type:text/html;charset=utf-8");
$a["color"]="red";
$a["taste"]="sweet";
$a["shape"]="round";
$a["name"]="apple";
$a[3]=4;
var_dump($a);
?>

The subscript can be omitted, and the index value will increase sequentially starting from 0 by default.

<?php
header("Content-type:text/html;charset=utf-8");
$a[]="red";
$a[]="sweet";
$a[]="round";
$a[]="apple";
$a[]=4;
var_dump($a);
?>

Method 2: Use [] to initialize all elements together

$数组变量名=[key1 => value1, key2 => value2, ..., keyN => valueN];

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$arr=["color"=>"red","taste"=>"sweet","shape"=>"round","name"=>"apple"];
var_dump($arr);
?>

key can be omitted, that is, you can specify the subscript without using the => symbol, and the default is the index array. The default index value also starts from 0 and increases in sequence.

<?php
header("Content-type:text/html;charset=utf-8");
$arr=["red","sweet","round","apple"];
var_dump($arr);
?>

Method 3: Use the array() function to initialize all elements together

$数组变量名 = array(key1 => value1, key2 => value2, ..., keyN => valueN);

The same key can be omitted, that is, If you do not use the => symbol to specify a subscript, it defaults to an indexed array. The default index value also starts from 0 and increases in sequence.

<?php
header("Content-type:text/html;charset=utf-8");
$arr1 = array("color"=>"red","taste"=>"sweet","shape"=>"round","name"=>"apple");
var_dump($arr1);
$arr2=array("red","sweet","round","apple");
var_dump($arr2);
?>

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