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 $array = array(); echo '<pre class="brush:php;toolbar:false">'; var_dump($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");
$array = array(0 => '香蕉', 1 => '苹果', 2 => '橙子', 3 => '榴莲');
echo '<pre class="brush:php;toolbar:false">';
var_dump($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");
$array = array('香蕉','苹果', '橙子','榴莲');
echo '<pre class="brush:php;toolbar:false">';
var_dump($array);
?>The running results are the same as those of the previous example.
Recommended learning: "PHP Video Tutorial"
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