PHP json_encode data Format 2 formats [] and {}

In PHP, after JSON formats the data, there are 2 forms of data:

1. When array is a continuous array starting from 0, the result of Json_encode is a string enclosed by []

$arr = Array (' A ', ' B ', ' C ')//["A", "B", "C"]

2. When array is not starting from 0 or discontinuous arrays, the result of Json_encode is a string of key-value patterns enclosed by {}

$arr = Array (' 1 ' + = ' a ', ' 2 ' = ' B ', ' 3 ' = ' C ')//{"1": "A", "2": "B", "3": "C"}

For data in this way, Json_decode (array) ($json) or Json_decode ($json, true) to normal is an array

PHP json_encode data Format 2 formats [] and {}