First look at the unset function syntax
unset
Deletes a variable.
Syntax: int unset (mixed Var);
return value: Integer
Function type: PHP system function
Content Description
This function deletes the variable and returns a true value for
Transferred from the Prophet Community https://xz.aliyun.com/t/24430x00 PrefaceUsually the site background can be configured to allow uploading attachments file type, general login background, add PHP type can upload php file Getshell. However, as
Will PHP unset release the memory ?. First, let's look at an example of var_dump (memory_get_usage (); $ alaruence; var_dump (memory_get_usage (); unset ($ a); var_dump (memory_get_usage ()); output (on my PC, let's look at an example
First let's look at an example
Copy Code code as follows:
Var_dump (Memory_get_usage ());
$a = "laruence";
Var_dump (Memory_get_usage ());
unset ($a);
Var_dump (Memory_get_usage ());
The output (on my PC, may vary
First, let's look at an example.Var_dump (memory_get_usage ());$ A = "laruence ";Var_dump (memory_get_usage ());Unset ($ );Var_dump (memory_get_usage ());Output (on my PC, the load extension may vary depending on the system, PHP version, and load
Objective:The foreach structure is introduced in PhP4, which is an easy way to iterate through an array. foreach makes it easier to get key-value pairs than a traditional for-loop. Before PhP5, foreach can only be used in arrays, and after php5, it
This article provides a detailed analysis of the foreach problem in php. For more information, see
Preface:The foreach structure is introduced in php4, which is a simple way to traverse arrays. Compared with the traditional for loop, foreach can
Comparison of foreach and while loops in php. Foreach and while are both loops in php, so what is their difference between foreach and while loops, and that performance will be better, next, I will introduce the differences between foreach and while
First, we use an array to simulate a parameter pass. Received is a set of IDs, which I name here $nums:
$nums [] = 1;
$nums [] = 2;
$nums [] = 3;
$nums [] = 4;
We then use the $data array to touch the contents of a data table, with ID, username:
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