I saw a question online:
The result of array("a")+array("b") is ___
("a","b")
("b","a")
("b")
("a")
Answer: D
Why does the result remain unchanged when two arrays of php are added?
Because, they are equivalent to array("0″=>"a")+array("0″=>"b"), their key names are the same, the former cannot be overwritten by the latter, if it is array("0″=>"a")+array("0″=>"b", "1″=>"c"), then the result is equal to array("0″=>"a","1″=>"c")
What happens if it is in the same array and there are the same key names?
See a piece of code in the official php manual:
Copy the codeThe code is as follows:
$switching = array( 10, // key = 0
5 => 6,
3 => 7,
'a' => 4,
11, // key = 6 (maximum of integer-indices was 5)
'8' => 2, // key = 8 (integer!)
'02' => 77, // key = '02'
0 => 12 // the value 10 will be overwritten by 12
);
5 => 6,
3 => 7,
'a' => 4,
11, // key = 6 (maximum of integer-indices was 5)
'8' => 2, // key = 8 (integer!)
'02' => 77, // key = '02'
0 => 12 // the value 10 will be overwritten by 12
);
It can be seen that if there is the same key name in the same array, the value of the previous key name will be overwritten.