Array_merge analysis of the difference between PHP merged array + and Array_merge

The main difference is that if the same key name appears in two or more arrays, the key name is a string or a number, you need to be aware
1) When the key name is a number, array_merge () will not overwrite the original value, but the + merge array will return the first occurrence as the final result, and the values of the following array with the same key name "Discard" (not overwrite)
2) When the key name is a character, + still returns the first occurrence as the final result, and discards the value of the following array with the same key name, but Array_merge () overwrites the previous value of the same key name
It is important to note that the array key form ' number ' is equivalent to the number

Copy the Code code as follows:

$a = Array (' A ', ' B ');
$b = Array (' C ', ' d ');
$c = $a + $b;
Var_dump ($a);
Var_dump (Array_merge ($a, $b));
$a = Array (0 = ' a ', 1 = ' B ');
$b = Array (0 = ' C ', 1 = ' B ');
$c = $a + $b;
Var_dump ($c);
Var_dump (Array_merge ($a, $b));
$a = Array (' A ', ' B ');
$b = Array (' 0 ' = ' c ', 1 = ' B ');
$c = $a + $b;
Var_dump ($c);
Var_dump (Array_merge ($a, $b));
$a = Array (0 = ' a ', 1 = ' B ');
$b = Array (' 0 ' = ' C ', ' 1 ' = ' B ');
$c = $a + $b;
Var_dump ($c);
Var_dump (Array_merge ($a, $b));

Results

Copy the Code code as follows:

Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
2 = String ' C ' (length=1)
3 = String ' d ' (length=1)
Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
2 = String ' C ' (length=1)
3 = String ' B ' (length=1)
Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
2 = String ' C ' (length=1)
3 = String ' B ' (length=1)
Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
Array
0 = String ' a ' (length=1)
1 = string ' B ' (length=1)
2 = String ' C ' (length=1)
3 = String ' B ' (length=1)

The above describes the Array_merge PHP merged array + and Array_merge analysis, including the array_merge aspects of the content, I hope that the PHP tutorial interested in a friend helpful.

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