How to define an array in php but not assign a value

You can use the array() function in php to define an array without assigning a value. The syntax format is "$array variable name=array();". The array() function can be used to create a new array. If it does not accept parameters, it will be an empty array; if it accepts a certain number of "key=>value" parameter pairs separated by commas, it will be an associative array.

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

Use array() Function definition array

Use the array() function to create a new array.

1. Define an empty array - define an array but do not assign a value

$数组变量名=array();

The sample code is as follows:

<?php
$array = array();
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
var_dump($array);
?>

The running results are as follows:

array (size=0)
  empty

2. Associative array

array() function accepts a certain number of key=>value parameter pairs separated by commas. The syntax format is as follows:

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

The sample code is as follows:

<?php
header("Content-type:text/html;charset=utf-8");
$array = array(0 => &#39;香蕉&#39;, 1 => &#39;苹果&#39;, 2 => &#39;橙子&#39;, 3 => &#39;榴莲&#39;);
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
var_dump($array);
?>

The running results are as follows:

array (size=4)
  0 => string '香蕉' (length=6)
  1 => string '苹果' (length=6)
  2 => string '橙子' (length=6)
  3 => string '榴莲' (length=6)

3. Index array

If you do not specify a subscript using the => symbol, it defaults to an indexed array. The default index value also starts from 0 and increases in sequence. The sample code is as follows:

<?php
header("Content-type:text/html;charset=utf-8");
$array = array(&#39;香蕉&#39;,&#39;苹果&#39;, &#39;橙子&#39;,&#39;榴莲&#39;);
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
var_dump($array);
?>

The running results are the same as those of the previous example.

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