Php merge array array_merge function operator plus sign and difference _ PHP Tutorial

Php merges array array_merge function operator plus signs and the difference. Array_merge () is described as follows in the Reference Manual: array_merge () combines two or more arrays, and the values in an array are appended to the values of the previous array. The returned result array_merge is described as follows in the reference manual:
Array_merge ()Combine two or more arrays. the values in an array are appended to the values of the previous array. Returns an array of results.
If the input array contains the same string key name, the value after the key name overwrites the previous value. However, if the array contains a number key name, the subsequent values will not overwrite the original values, but will be appended to the back.
The two differences are:
1. when the array KEY name is a numeric KEY, when the two arrays to be merged have a numeric KEY with the same name, using array_merge () will not overwrite the original value, when "+" is used to merge arrays, the first value will be returned as the final result, and the values of the following arrays with the same key name will be discarded (note: instead of overwriting, the value that appears first is retained ). Example:

The code is as follows:

$ Array1 = array (1 => '0 ');
$ Array2 = array (1 => "data ");
$ Result1 = $ array2 + $ array1;/* The result is a value of $ array2 */
Print_r ($ result );
$ Result = $ array1 + $ array2;/* The result is a value of $ array1 */
Print_r ($ result );
$ Result3 = array_merge ($ array2, $ array1);/* The result is the value of $ array2 and $ array1, and the key name is reassigned */
Print_r ($ result3 );
$ Result4 = array_merge ($ array1, $ array2);/* The result is $ array1 and $ array2, and the key name is reassigned */
Print_r ($ result4 );

Output result:

The code is as follows:

Array
(
[1] => data
)
Array
(
[1] => 0
)
Array
(
[0] => data
[1] => 0
)
Array
(
[0] => 0
[1] => data
)

2. when the same array key name is a character, the "+" operator is the same as the key name is a number, but array_merge () will overwrite the value of the previous same key name.
Example:
　　

The code is as follows:

$ Array1 = array ('asd '=> '0 ');
$ Array2 = array ('asd '=> "data ");
$ Result1 = $ array2 + $ array1;/* The result is a value of $ array2 */
Print_r ($ result );
$ Result = $ array1 + $ array2;/* The result is a value of $ array1 */
Print_r ($ result );
$ Result3 = array_merge ($ array2, $ array1);/* The result is $ array1 */
Print_r ($ result3 );
$ Result4 = array_merge ($ array1, $ array2);/* The result is $ array2 */
Print_r ($ result4 );

Output result:

The code is as follows:

Array
(
[Asd] => data
)
Array
(
[Asd] => 0
)
Array
(
[Asd] => 0
)
Array
(
[Asd] => data
)

Array_merge () combines two or more arrays. the values in an array are appended to the values of the previous array. Returned result...