Detailed explanation of PHP array assignment method, detailed explanation of array assignment_PHP tutorial

Detailed explanation of PHP array assignment method, detailed explanation of array assignment

PHP array is still relatively commonly used, so I studied PHP array assignment and shared it with you here. I hope Useful for everyone.

The so-called array is a set of variables stored in the computer's memory. These variables can be of different types, including integers, Boolean values, strings, etc. It can be said that an array is a small database in memory. It provides a quick way for us to access data - it can save IO or frequent database access to improve some performance, so there are many operations on the array. .
How to create an array in PHP, you can use the following method:

One of the methods creates an array:

<&#63;php 
$a="abcd"; 
print($a[0]." ".$a[1]." ".$a[2]." ".$a[3]." "); 
&#63;> 

Result: a b c d

Method 2:

<&#63;php 
$http=array("www","helpphp","cn");  
print($http[0].".".$http[1].".".$http[2]);  
&#63;> 

Knowledge description:

1. We can see from the previous example that arrays in PHP start from the subscript (index) by default to indicate the position of the variable in the array, which means we can use: $ variable name [index] to access us The array created.

2. We use the array() language structure to create data. In the array, if the subscript is not explicitly specified, the index starts from 0 and increases by default. The array we created has been saved in memory, but after the data is used, we need to do some cleaning to ensure memory leaks.

How to assign values ​​to PHP arrays? As follows:

$My_array=array()； 
$My_array[]=”www” 
$My_array[]=”helpphp”; 
$My_array[]=”cn”; 

Through the above method, I created an empty array for the variable using the array language structure, and assigned a value to $My_array in the following statement. In the previous section, we know that the array subscript (index), from It will automatically increment starting from 0, which means that the following statement will output helpphp.
Print $My_array[1];
If you want to output $My_array all at once, you can use print_r($My_array). How to destroy the array or the elements in the array. To complete the above task, just use the unset() function, which can delete the entire array. Or an element in the array, as follows:
unset($My_array[0];
unset($My_array);
It should be noted that after deleting the array element, the index value will retain its original position and the index will not be readjusted. You only need to compare after deletion to find this phenomenon. Use var_dump() to view more detailed things in the array, as follows:
Var_dump($My_array);

The above is to teach you the PHP array assignment method. I hope it will inspire your learning.

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