Common but useful functions in php

. Array_flip ($ arr); W3C explains that the function returns an inverted array. if the same value appears multiple times, the last key name is used as its value, all other key names will be lost. If the data type of the value in the original array is not a string or integer, the function reports an error.

1. array_flip ($ arr); W3C explains that the function returns an inverted array. if the same value appears multiple times, the last key name is used as its value, all other key names will be lost. If the data type of the value in the original array is not a string or integer, the function reports an error.

 

 1, "B" => 1, "c" => 2); $ trans = array_flip ($ trans); print_r ($ trans);?>

The result is:

Array ([1] => B [2] => c)

2. mkdir (path, mode, recursive, context) describes its third parameter: recurisive is required and specifies whether to set the recursive mode. For example, I want to create E: \ abc \ AB \ c (three folders abc \ AB \ c do not exist ).

 

In this way, the directory will be created cyclically.