Converting array to JSON string when array already contains JSON strings

Question

I have an array that contains a JSON string.

Array
(
    [0] => Array
        (
            [name] => Original
            [nutrients] => {"calories":{"value":2500,"operator":2},"protein":{"value":500,"operator":1},"carbs":{"value":200,"operator":0},"fat":{"value":50,"operator":0},"sugar":{"value":1,"operator":2}}
        )

    [1] => Array
        (
            [name] => Rest
            [nutrients] => {"calories":{"value":5000,"operator":2},"sugar":{"value":10,"operator":2}}
        )

)

I want to turn the whole array into a JSON string

echo json_encode($array);

But this throws a \ in front of all quotes

[{"name":"Original","nutrients":"{\"calories\":{\"value\":2500,\"operator\":2},\"protein\":{\"value\":500,\"operator\":1},\"carbs\":{\"value\":200,\"operator\":0},\"fat\":{\"value\":50,\"operator\":0},\"sugar\":{\"value\":1,\"operator\":2}}"},{"name":"Rest","nutrients":"{\"calories\":{\"value\":5000,\"operator\":2},\"sugar\":{\"value\":10,\"operator\":2}}"}]

This problem comes about because the nutrients value is already a JSON string.

How can I convert an array into a JSON string when it already contains JSON strings, while having no slashes in front of the quotes?

(1) Either write a custom JSON generator. (2) Or decode the jsonish strings in that array structure, then reencode everything. — mario
– mario, Commented Aug 31, 2015 at 2:13
Loop through array to assign each json string to a new array, replace with placeholder, json encode array, replace original json strings? — kittykittybangbang
– kittykittybangbang, Commented Aug 31, 2015 at 2:14
That's fine that it throws a `\` in front of the quotes. JSON properties can be quoted or not. You don't have to use the quotes if there isn't a space or character situation that does not conform to a normal property naming standards. Your problem is that you have entire Strings with JSON inside of them — StackSlave
– StackSlave, Commented Aug 31, 2015 at 2:15
json_encode() is usually used to encode PHP associative arrays, not JavaScript Objects that are already Strings in your PHP. — StackSlave
– StackSlave, Commented Aug 31, 2015 at 2:22

anhlc · Accepted Answer · 2015-08-31 03:26:49Z

1

Use json_decode to convert 'nutrients' to array.

foreach($array as &$a){
 $a['nutrients'] = json_decode($a['nutrients']); 
}

Then

echo json_encode($array);

answered Aug 31, 2015 at 3:26

anhlc

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someOne · Accepted Answer · 2015-08-31 04:17:14Z

How can I convert an array into a JSON string when it already contains JSON strings, while having no slashes in front of the quotes?

If you want to preserve the JSON values as strings; then, you can't, and you shouldn't be able to!

If your array already contains some JSON values (in which they'll have some quotation marks: ") and you want to encode that array into a JSON string, then the quotation marks must be properly escaped, what you get correctly; otherwise, the entire JSON string will be corrupt because of miss-quotation-mark matches.

That's because the " has a special meaning in JSON, but the \" means the "double quotation mark character" not the special token of "; for example, removing the backslashes from the valid JSON string causes some syntax errors for sure:

$json = '[{"name":"Original","nutrients":"{\"calories\":{\"value\":2500,\"operator\":2},\"protein\":{\"value\":500,\"operator\":1},\"carbs\":{\"value\":200,\"operator\":0},\"fat\":{\"value\":50,\"operator\":0},\"sugar\":{\"value\":1,\"operator\":2}}"},{"name":"Rest","nutrients":"{\"calories\":{\"value\":5000,\"operator\":2},\"sugar\":{\"value\":10,\"operator\":2}}"}]';
$json_noBackslashes = str_replace('\\', '', $json);
$json_decoded = json_decode($json_noBackslashes);
echo json_last_error_msg(); // Syntax error

Subash · Accepted Answer · 2015-08-31 04:50:46Z

0

You should be able to json_decode the json data first, then put it back to the original array. After that, you can encode the whole array again to get the desired output.

foreach ($data as $datum) {
   $data['nutrients'] = json_decode($data['nutrients']);
}

json_encode($data);

answered Aug 31, 2015 at 4:50

Subash

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