无法通过变量解码json字符串。

$result = json_decode(file_get_contents('route.json'),true);

// the json file is here: https://myweb.polyu.edu.hk/~11010482d/FSP/route.json

print_r($result);

//it show '[{"X":"264","Y":"115"},{"X":"328","Y":"115"},{"X":"309","Y":"216"},{"X":"256","Y":"222"},{"X":"227","Y":"217"},{"X":"227","Y":"238"},{"X":"223","Y":"221"},{"X":"223","Y":"205"},{"X":"254","Y":"206"},{"X":"309","Y":"182"},{"X":"309","Y":"98"},{"X":"327","Y":"98"}]'

//i have tried the string not using $result as variable to decode and it works.

$abcdefg = json_decode('[{"X":"264","Y":"115"},{"X":"328","Y":"115"},{"X":"309","Y":"216"},{"X":"256","Y":"222"},{"X":"227","Y":"217"},{"X":"227","Y":"238"},{"X":"223","Y":"221"},{"X":"223","Y":"205"},{"X":"254","Y":"206"},{"X":"309","Y":"182"},{"X":"309","Y":"98"},{"X":"327","Y":"98"}]',true);

print_r($abcdefg);

//it show Array ( [0] => Array ( [X] => 264 [Y] => 115 ) [1] => Array ( [X] => 328 [Y] => 115 ) [2] => Array ( [X] => 309 [Y] => 216 ) [3] => Array ( [X] => 256 [Y] => 222 ) [4] => Array ( [X] => 227 [Y] => 217 ) [5] => Array ( [X] => 227 [Y] => 238 ) [6] => Array ( [X] => 223 [Y] => 221 ) [7] => Array ( [X] => 223 [Y] => 205 ) [8] => Array ( [X] => 254 [Y] => 206 ) [9] => Array ( [X] => 309 [Y] => 182 ) [10] => Array ( [X] => 309 [Y] => 98 ) [11] => Array ( [X] => 327 [Y] => 98 ) )
// and i want this result for the previous way.
$result = json_decode(file_get_contents('route.