Using json_encode() on an array with numeric keys produces an object string with keys instead of an array string [duplicate]

Question

I've encoded an Array I've made using the inbuilt json_encode(); function. I need it in the format of an Array of Arrays like so:

[["Afghanistan",32,12],["Albania",32,12]]

However, it is returning as:

{"2":["Afghanistan",32,12],"4":["Albania",32,12]}

How can I remove these row numbers without using any regex trickery?

Answer 1

If the array keys in your PHP array are not consecutive numbers, json_encode() must make the other construct an object since JavaScript arrays are always consecutively numerically indexed.

Use array_values() on the outer structure in PHP to discard the original array keys and replace them with zero-based consecutive numbering:

Example:

// Non-consecutive 3number keys are OK for PHP
// but not for a JavaScript array
$array = array(
  2 => array("Afghanistan", 32, 13),
  4 => array("Albania", 32, 12)
);

// array_values() removes the original keys and replaces
// with plain consecutive numbers
$out = array_values($array);
json_encode($out);
// [["Afghanistan", 32, 13], ["Albania", 32, 12]]

Answer 2

json_encode() function will help you to encode array to JSON in php.

if you will use just json_encode function directly without any specific option, it will return an array. Like mention above question

$array = array(
  2 => array("Afghanistan",32,13),
  4 => array("Albania",32,12)
);
$out = array_values($array);
json_encode($out);
// [["Afghanistan",32,13],["Albania",32,12]]

Since you are trying to convert Array to JSON, Then I would suggest to use JSON_FORCE_OBJECT as additional option(parameters) in json_encode, Like below

<?php
$array=['apple','orange','banana','strawberry'];
echo json_encode($array, JSON_FORCE_OBJECT);
// {"0":"apple","1":"orange","2":"banana","3":"strawberry"} 
?>

Answer 3

I want to add to Michael Berkowski's answer that this can also happen if the array's order is reversed, in which case it's a bit trickier to observe the issue, because in the json object, the order will be ordered ascending.

For example:

[
    3 => 'a',
    2 => 'b',
    1 => 'c',
    0 => 'd'
]

Will return:

{
    0: 'd',
    1: 'c',
    2: 'b',
    3: 'a'
}

So the solution in this case, is to use array_reverse before encoding it to json

Answer 4

I had a problem with accented characters when converting a PHP array to JSON. I put UTF-8 stuff all over the place but nothing solved my problem until I added this piece of code in my PHP while loop where I was pushing the array:

$es_words[] = array(utf8_encode("$word"),"$alpha","$audio");

It was only the '$word' variable that was giving a problem. Afterwards it did a jason_encode no problem.

Hope that helps