Basic functions of PHP array operations

The key name and value of the array
Array_values ($arr); Get the value of an array
Array_keys ($arr); Gets the key name of the array
Array_flip ($arr); the values in the array are exchanged with the key names (if there are duplicates, the previous one will be overwritten by the following)
In_array ("Apple", $arr); Retrieve Apple in an array
Array_search ("Apple", $arr); Retrieve Apple in an array if there is a return key name
Array_key_exists ("Apple", $arr); Retrieves whether the given key name exists in the array
Isset ($arr [Apple]): Retrieves whether the given key name exists in the array

An internal pointer to an array
Current ($arr); Returns the cell in the array
POS ($arr); Returns the current cell in the array
Key ($arr); Returns the key name of the current cell in the array
Prev ($arr); Rewind the internal pointer in the array back to a
Next ($arr); Move the inner pointer in the array forward one
End ($arr); point the inner pointer in the array to the last cell
Reset ($arr; point the inner pointer in the array to the first cell
Each ($arr), constructs an array that returns a key name/value of the current element of the array, and moves the array pointer forward one
List ($key, $value) =each ($arr); Gets the key name and value of the current element of the array

Conversions between arrays and variables
Extract ($arr); used to convert an element in an array into a variable and import it into the current file, the key name as the variable name, and the value as the variable value
Note: (The second parameter is very important, can see the manual use) method of use echo $a;
Compact (VAR1,VAR2,VAR3); Create an array with the given variable name

Basic functions for PHP array operations