Php tips form a new array by exchanging the keys and values of the array, and obtain the key by searching for the value.

Php tips -- exchange keys and values of an array to form a new array, and find the value to obtain the key implementation method.

Php tips -- exchange keys and values of an array to form a new array, and find the value to obtain the key implementation method.

The Code is as follows:
$ Cityname = array_flip ($ city_DB [name]); // exchange the keys and values of the array to form a new array.
$ City_name = array_search ($ city_id, $ cityname, true); // obtain the key for the search Value