How to count the number of elements present in a JSON object?

Question

I have a PHP/JSON as show below.

JSON:

{"posts_id_en":"101, 102, 103","posts_id_fr":"", "reports_id_en":"101, 102", "reports_id_fr":"101"}

PHP code:

echo count(explode(",", $data->posts_id_en));    //  Line A  (3)

echo count(explode(",", $data->posts_id_fr));    // Line B   (1)

echo count(explode(",", $data->reports_id_en));    // Line C  (2)

echo count(explode(",", $data->reports_id_fr));    // Line D  (1)

Line A php code, Line C php code and Line D php code print 3, 2, and 1.

Problem Statement:

I am wondering what changes I need to make in the php code above at Line B so that it prints 0 as there are no elements inside posts_id_fr

Whatever values we enter in the form get stored in the JSON. I am not allowed to change the structure of the JSON. Let me know if you need more information. — user1950349, Sep 16 '20 at 21:02

Dark Knight · Accepted Answer · 2020-09-16T21:11:51.487

You just need to make sure there is no empty values inside that array. Because when empty string is exploded it will create one element with value as blank.

Remove those values using array_filter

echo count(array_filter(explode(",", $data->posts_id_fr)));

// Will print 0

Just in case if you want to loop through as suggested by GrumpyCrouton

foreach($data as $key => $value)
{
  echo $key . ' : ' . count(array_filter(explode(",", $value))) . PHP_EOL;
}

Output:
posts_id_en : 3
posts_id_fr : 0 
reports_id_en: 2
reports_id_fr: 1

RiggsFolly · Answer 2 · 2020-09-16T21:10:16.097

0

You must check if the value is set before trying to use the value

$str = '{"posts_id_en":"101, 102, 103","posts_id_fr":"", "reports_id_en":"101, 102", "reports_id_fr":"101"}';

$obj = json_decode($str);

foreach ( $obj as $o=>$v) {
    echo $o . ' ';
    echo strlen($v) > 0 ? count(explode(",", $v)) : 0 ;
    echo PHP_EOL;
}

Results

posts_id_en 3
posts_id_fr 0
reports_id_en 2
reports_id_fr 1

edited Sep 16 '20 at 21:10

answered Sep 16 '20 at 21:05

RiggsFolly

93,638
21
103
149

score 0 · Answer 3 · answered Sep 16 '20 at 22:00

Slight variation here, you can use preg_split and use a flag to ignore empty splits. Here we are splitting on non-digits.

<?php

$str = '{"posts_id_en":"101, 102, 103","posts_id_fr":"", "reports_id_en":"101, 102", "reports_id_fr":"101"}';
$arr = json_decode($str, true);

$arr = array_map(function($item) {
    $nums = preg_split('/[^0-9]/', $item, -1, PREG_SPLIT_NO_EMPTY);

    return $nums;
}, $arr);

var_export($arr);

$arr = array_map('count', $arr);

var_export($arr);

Output:

array (
  'posts_id_en' => 
  array (
    0 => '101',
    1 => '102',
    2 => '103',
  ),
  'posts_id_fr' => 
  array (
  ),
  'reports_id_en' => 
  array (
    0 => '101',
    1 => '102',
  ),
  'reports_id_fr' => 
  array (
    0 => '101',
  ),
)array (
  'posts_id_en' => 3,
  'posts_id_fr' => 0,
  'reports_id_en' => 2,
  'reports_id_fr' => 1,
)

The intermediate step is included so you can see the result of the preg_split.

score 0 · Answer 4 · answered Sep 16 '20 at 22:24

0

echo count(preg_split("/,/", $data->posts_id_fr,-1, PREG_SPLIT_NO_EMPTY));

answered Sep 16 '20 at 22:24

Pablo Escobar

393
2
16

How to count the number of elements present in a JSON object?

4 Answers4