How to declare an array in php: two ways to declare an array

How to declare an array in php?

##There are two main ways to declare arrays in PHP: one One is to declare an array using the array() function, and the other is to declare an array directly by assigning values ​​to the array elements. (What is a PHP array?)The way to declare an array using the array() function is as follows:

array array([mixed ...])

The syntax of the parameter mixed is key=>value, Use commas to separate multiple mixed parameters to define indexes and values ​​respectively. The index can be a number or a string. If the index is omitted, an integer index starting from 0 is automatically generated. If the index is an integer, then the next index generated will be the largest integer index so far +1. If two identical indexes are defined, the later index will overwrite the previous index.

The data type of each data element in the array can be different, or it can be an array type. When mixed is an array type, it is a two-dimensional array (we will have details about the declaration of two-digit arrays later. explain).

When using the array() function to declare an array, the array subscript can be either a numeric index or an associative index. Use "=>" to connect subscripts and array element values, and use commas to separate different array elements!

Applying the array() function to define an array is more flexible. Only the array element values ​​can be given in the function body instead of the key values. For example:

<?php
$array = array("asp","PHP","JSP");    //定义数组
print_r($array);                      //输出数组元素
?>

The output result is:

Note: You can create an empty space by assigning an array() function without parameters to a variable. Array, then use square brackets [ ] syntax to add array element values!

PHP provides the array() function to create arrays. When using the data of one of the elements, you can directly use their order in the number to get the value. This order is called the subscript of the array. For example:

<?php
$array = array("asp","PHP","JSP"); //定义数组
echo $array[1]                       //输出数组元素的第二个下标值
?>

The output result is:

Note: Use the array() function to define an array, and the subscript starts from 0 by default. , instead of 1, and then increase by 1 in sequence. So the element with index 2 is the 3rd element of the array. And so on!

The following declares the array through the array() function. Example code:

<?php
header("Content-Type:text/html; charset=utf-8");
$array = array("1"=>"PHP","2"=>"中","3"=>"文","4"=>"网");   //声明数组
print_r($array);                                       //输出数组元素
echo "<br>";
echo $array[1];                                      //输出数组元素的值
echo $array[2];                                      //输出数组元素的值
echo $array[3];                                      //输出数组元素的值
echo $array[4];                                     //输出数组元素的值
?>

The output result is:

## Another more flexible way to declare an array in #PHP is to directly assign values ​​to array elements.

If you do not know the size of the array when you create it, or the size of the array may change when you actually write the program, it is better to use this method of array creation.

In order to deepen the understanding of this array declaration method, the following is a specific example to explain the array declaration method. The sample code is as follows:

<?php
header("Content-Type:text/html; charset=utf-8");
$array[1]="PHP";
$array[2]="中";
$array[3]="文";
$array[4]="网";

print_r($array);    //输出所创建数组的结构
?>

The output result is:

Note: When declaring an array by directly assigning values ​​to array elements, the array names in the same array element are required to be the same.

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Related tutorial recommendations

】1. Relevant topic recommendations: "

php array (Array) Special Topic》2. Related video course recommendations: "

Creation and Access of PHP Arrays: 3 Creation Methods and 2 Access method》

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