Reputation: 2027

PHP json_encode encoding numbers as strings

I am having one problem with the PHP json_encode function. It encodes numbers as strings, e.g.

array('id' => 3)

becomes

"{ ["id": "3", ...)

When js encounters these values, it interprets them as strings and numeric operations fail on them. Does anyone know some way to prevent json_encode from encoding numbers as strings? Thank you!

Upvotes: 172

Answers (18)

lisandro

Reputation: 506

I have this problem in a curl sending json that required some fields to be integer and other fields string, but some of the values of the string fields were in fact numbers so JSON_NUMERIC_CHECK didn't worked because it converted everything that looked as a number to number. The solution I've found was to add characters representing future double quotes, in my case I've used @ as I knew it was impossible to have this character in my data, to the fields representing string values

$analysis = array(

'SampleAnalysisId'  => $record[3],
'DisplayValue' => '@'.$record[4].'@',
'MeasurementUnit' => '@'.$record[5].'@',
'SampleAnalysisConclusionId'  => $record[6],
'Uncertaint' => '@'.$record[7].'@',
'K' => '',
'QuantificationLimit' => '@'.$record[8].'@',
'DetectionLimit' => '@'.$record[9].'@',
'Veff' => ''

);

Then after encoding I replaced the double quotes for empty and then replaced the '@' for double quotes.

$str = json_encode($analysis,JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES );
$str = str_replace('@','"',str_replace('",',',',str_replace(':"',':',$str)));

Resulting in a formatted json according to my need

[{"SampleAnalysisId":10479,"DisplayValue":"6,3","MeasurementUnit":"mg/L","SampleAnalysisConclusionId":1,"Uncertaint":"0,194463","K":,"QuantificationLimit":"1","DetectionLimit":"0,30","Veff":"}]

Upvotes: 1

Rory Jarrard

Reputation: 391

So Pascal MARTIN isn't getting enough credit here. Checking for numeric values on every JSON return is not feasable for an existing project with hundreds of server side functions.

I replaced php-mysql with php-mysqlnd, and the problem went away. Numbers are numbers, strings are strings, booleans are boolean.

Upvotes: 4

Rahul Gupta

Reputation: 23

You can use (int) if any issue occurs!! It will work fine.

Upvotes: 1

Derrick Miller

Reputation: 1951

Casting the values to an int or float seems to fix it. For example:

$coordinates => array( 
    (float) $ap->latitude,
    (float) $ap->longitude 
);

Upvotes: 2

user5183775

Reputation:

it is php version the problem, had the same issue upgraded my php version to 5.6 solved the problem

Upvotes: 2

Rijk

Reputation: 11301

Note that since PHP 5.3.3, there's a flag for auto-converting numbers (the options parameter was added in PHP 5.3.0):

$arr = array( 'row_id' => '1', 'name' => 'George' );
echo json_encode( $arr, JSON_NUMERIC_CHECK ); // {"row_id":1,"name":"George"}

Upvotes: 407

Santini Arnaud

Reputation: 19

Like oli_arborum said, I think you can use a preg_replace for doing the job. Just change the command like this :

$json = preg_replace('#:"(\d+)"#', ':$1', $json);

Upvotes: -3

mouckatron

Reputation: 1289

I, likewise was reading from a DB (PostgreSQL) and everything was a string. We loop over each row and do things with it to build up our final results array, so I used

$result_arr[] = array($db_row['name'], (int)$db_row['count']);

within the loop to force it to be an integer value. When I do json_encode($result_arr) now, it correctly formats it as a number. This allows you to control what is and is not a number coming from your database.

EDIT:

The json_encode() function also has the ability to do this on the fly using the JSON_NUMERIC_CHECK flag as a second argument to it. You need to be careful using it though as shown in this users example in the documentation (copied below): https://www.php.net/manual/en/function.json-encode.php#106641

<?php
// International phone number
json_encode(array('phone_number' => '+33123456789'), JSON_NUMERIC_CHECK);
?>

And then you get this JSON:

{"phone_number":33123456789}

Upvotes: 36

Leon

Reputation: 1863

Just run into the same problem and was the database returning the values as strings.

I use this as a workaround:

$a = array(
    'id' => $row['id'] * 1,
    'another' => ...,
    'ananother' => ...,
);
$json = json_encode($a);

That is multiplying the value by 1 to cast it into a number

Hope that helps someone

Upvotes: -1

Yar

Reputation: 4561

$rows = array();
while($r = mysql_fetch_assoc($result)) {
    $r["id"] = intval($r["id"]); 
    $rows[] = $r;
}
print json_encode($rows);

Upvotes: 0

habibillah

Reputation: 111

try $arr = array('var1' => 100, 'var2' => 200); $json = json_encode( $arr, JSON_NUMERIC_CHECK);

But it just work on PHP 5.3.3. Look at this PHP json_encode change log http://php.net/manual/en/function.json-encode.php#refsect1-function.json-encode-changelog

Upvotes: 9

OzgurH

Reputation: 453

For sake of completeness (as I can't add comments yet), let me also add this detail as another answer:

(Edit: To be read after realizing that the source data (i.e. in the OP's case, database result set) could be the problem (by returning numeric columns as strings), and json_encode() in fact was not the source of the problem)

Manual pages of both "mysql_fetch_array":

Returns an array of strings that corresponds to the fetched row,

... and "mysql_ fetch_ row":

Returns an numerical array of strings that corresponds to the fetched row

clearly states that; the entries in the returned array will be strings.

(I was using the DB class in phpBB2 (yes I know, it's obsolete!), and "sql_fetchrow()" method of that class uses "mysql_fetch_array()")

Not realizing that, I also ended up finding this question, and understanding the problem! :)

As Pascal Martin stated above in his follow-up comments, I believe a solution that takes care of the "incorrect type" problem at the source (i.e. by using the "mysql_field_type()" function and doing the casting right after fetch, (or other fetch methods like "object"?)) would be the better in general.

Upvotes: 2

balucio

Reputation: 124

I also had the same problem processing data from the database. Basically the problem is that the type in the array to convert in json, is recognized by PHP as a string and not as integer. In my case I made a query that returns data from a DB column counting row. The PDO driver does not recognize the column as int, but as strings. I solved by performing a cast as int in the affected column.

Upvotes: 0

Jay Andrew Allen

Reputation: 39

The following test confirms that changing the type to string causes json_encode() to return a numeric as a JSON string (i.e., surrounded by double quotes). Use settype(arr["var"], "integer") or settype($arr["var"], "float") to fix it.

<?php

class testclass {
    public $foo = 1;
    public $bar = 2;
    public $baz = "Hello, world";
}

$testarr = array( 'foo' => 1, 'bar' => 2, 'baz' => 'Hello, world');

$json_obj_txt = json_encode(new testclass());
$json_arr_txt = json_encode($testarr);

echo "<p>Object encoding:</p><pre>" . $json_obj_txt . "</pre>";
echo "<p>Array encoding:</p><pre>" . $json_arr_txt . "</pre>";

// Both above return ints as ints. Type the int to a string, though, and...
settype($testarr["foo"], "string");
$json_arr_cast_txt = json_encode($testarr);
echo "<p>Array encoding w/ cast:</p><pre>" . $json_arr_cast_txt . "</pre>";

?>

Upvotes: 3

oli_arborum

Reputation: 398

I'm encountering the same problem (PHP-5.2.11/Windows). I'm using this workaround

$json = preg_replace( "/\"(\d+)\"/", '$1', $json );

which replaces all (non-negative, integer) numbers enclosed in quotes with the number itself ('"42"' becomes '42').

PHP json_encode encoding numbers as strings

Answers (18)

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