Rebuild a json data remove duplicate value in one child node - php

Question

Here is some json data:
[
{"a":"abc","b:":"10"},//"a":"abc"
{"a":"abd","b:":"12"},
{"a":"abc","b:":"14"},//"a":"abc"
{"a":"abe","b:":"15"},
{"a":"abf","b:":"16"},
{"a":"abg","b:":"17"},//"a":"abg"
{"a":"abg","b:":"19"}//"a":"abg"
]
I want remove all the duplicate values in the child node "a" (remain the first appear one).
Output =>
[
{"a":"abc","b:":"10"},//first appear "a":"abc"
{"a":"abd","b:":"12"},
{"a":"abe","b:":"15"},
{"a":"abf","b:":"16"},
{"a":"abg","b:":"17"}//first appear "a":"abg"
]

Answer 1

This is tested and appears to work as you've described:
$json = <<<JSON
[
{"a":"abc","b:":"10"},
{"a":"abd","b:":"12"},
{"a":"abc","b:":"14"},
{"a":"abe","b:":"15"},
{"a":"abf","b:":"16"},
{"a":"abg","b:":"17"},
{"a":"abg","b:":"19"}
]
JSON;
$json_array = json_decode( $json, TRUE );
$new_array = array();
$exists = array();
foreach( $json_array as $element ) {
if( !in_array( $element['a'], $exists )) {
$new_array[] = $element;
$exists[] = $element['a'];
}
}
print json_encode( $new_array );
It outputs [{"a":"abc","b:":"10"},{"a":"abd","b:":"12"},{"a":"abe","b:":"15"},{"a":"abf","b:":"16"},{"a":"abg","b:":"17"}], which I believe matches your desired output.