in_array large array query performance issues

Problem

Recently when implementing a project interface, I found that when the array is too large, the data return speed is a bit slow. The maximum response time for interface data return is 2 seconds. After repeated debugging, it was found that the longest part of the code segment is in the in_array() function.

Solution process

I found an article on stackoverflow that provided me with solution ideas
- which is faster, array_key_exists or array_search?

The article says:

array_key_exists is much faster. array_search must traverse the whole array, so it is O(n). array_key_exists is a hash table lookup , so it is O(1).

－－－－Separating line－－－－

I think it's faster for PHP to check for keys (array_key_exists() or simply isset($array[$ key])). To search for a value, PHP must cycle through the array; to search for a key PHP will use a hash function.

The array is used to save the user account and is never destroyed and stored in memory.

Original array
$array=array('account1','account2','$account3');

Modified array
$array=array('account1'=>0,'account2' =>0,'$account3'=>0)

Use isset($array[$account])) to detect whether the account exists in the array

Summary

Due to the in_array() function Traversing the array is O(n), and the time consumption will increase as n (array length) increases. Therefore, efficiency issues should be considered when using the in_array() function for large arrays.

When faced with large array queries, you should try to use key queries instead of value queries in PHP.

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The above introduces the performance issues of in_array large array query, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.