How to determine whether an element exists in an array in php

php method to determine whether an element exists in an array: 1. Search for a given value in the array through the "in_array" function; 2. Use the "array_key_exists()" function to determine whether a specified element exists in an array key; 3. Use "array_search()" to find a key value in the array.

The operating environment of this tutorial: windows10 system, PHP version 8.1, DELL G3 computer

How does php determine whether an array exists? A certain element?

Find whether an element exists in an array in php

To find whether an element is in an array, there are three ways to do it:

in_array

The in_array function searches an array for a given value. in_array(value,array,type)type optional. If this parameter is set to true, it is checked whether the type of the searched data and the value of the array are the same.

array_key_exists

array_key_exists() function determines whether the specified key exists in an array. If the key exists, it returns true, otherwise it returns false. array_key_exists(key,array)

array_search

array_search() function is the same as in_array(), searching for a key value in the array. If the value is found, the key of the matching element is returned. If not found, returns false. array_search(value,array,strict)

From this point of view, when the amount of data is not large, such as less than 1000, any search method can be used, and it will not become a bottleneck;

When the amount of data is relatively large, it is more appropriate to use array_key_exists.

Of course the memory occupied by array_key_exists here is relatively large. According to calculations

the array structure is: array(1, 2, 3, ..) and array(1 => true, 2 => ; false, ..)

Their memory usage ratio is 1:2;

This is related to the internal implementation. In fact, the first and second data structures in PHP are similar , are all associative arrays.

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