Home > Article > Backend Development > Summary of various methods of finding array elements in PHP_PHP Tutorial
Data query in php can be classified into one-dimensional array search and multi-dimensional array search. If it is a simple one-dimensional array, we can directly use in_array, array_search and traversal to instantiate it. If it is a multi-dimensional array, we need to use other methods. .
For a one-dimensional array we can operate as follows
in_array 'Function searches for a given value in an array. 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 an 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, array_key_exists is more appropriate.
Of course, the memory occupied by array_key_exists here is relatively large. According to calculations
Binary method to find whether an array contains a certain element, compatible with forward and reverse order, code implementation:
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Example 2
PHP Find the i-th smallest element in an array
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#Randomly select the i-th smallest number and use random quick sort to achieve |