PHP number_format does not return a value

Question

Relevant section of current code:

$xml=simplexml_load_file($file);
$number=$xml->data->value;
imagettftext($image,$size,$angle,$x,$y,$colour,$font,$number);

The goal of this is to display a value stored in an xml file, which currently works as is. However, larger numbers are a bit of an eyesore. I figured number_format would fix this, so I tried:

$xml=simplexml_load_file($file);
$number=$xml->data->value;
imagettftext($image,$size,$angle,$x,$y,$colour,$font,number_format($number));

And:

$xml=simplexml_load_file($file);
$number=number_format($xml->data->value);
imagettftext($image,$size,$angle,$x,$y,$colour,$font,$number);

And:

$xml=simplexml_load_file($file);
$number=$xml->data->value;
$number=number_format($number);
imagettftext($image,$size,$angle,$x,$y,$colour,$font,$number);

In all three cases, no number ends up being displayed on the image I'm trying to generate. Like I said though, this works just fine without number_format. The xml file is structured like so:

<xmldata>
    <data>
        <value>123456</value>
    </data>
</xmldata>

number_format() always returns a value, in this case a NULL (and a warning if your error logging was enabled) — Mark Baker
– Mark Baker, Commented Nov 21, 2017 at 16:24
Try casting the value from your xml to an int or a float before calling number_format() (var_dump $xml->data->value; to see what you're actually getting back; it should be a simplexmlelement object) — Mark Baker
– Mark Baker, Commented Nov 21, 2017 at 16:24
If yo get a 500 error, then you've typo'd something or created an error - DEMO — Mark Baker
– Mark Baker, Commented Nov 21, 2017 at 16:48
I thought as much, though I'm getting no syntax errors. I think Alvaro's answer solved the issue though. Just going to double check everything works first... — Hiigaran
– Hiigaran, Commented Nov 21, 2017 at 16:50

Álvaro González · Accepted Answer · 2017-11-21 16:40:55Z

2

PHP isn't a black box so you can (and should) inspect your variables. You can install a debugger or dump them to screen. You also need to enable full error reporting because your code should be triggering a warning that you are not seeing:

Warning: number_format() expects parameter 1 to be double, object given

I'll jump a few steps and share a carefully composed snippet:

<?php
$xml = simplexml_load_string('<xmldata>
    <data>
        <value>123456</value>
    </data>
</xmldata>');
$value = $xml->data->value;
var_dump($value, 2*$value, number_format($value), number_format(2*$value));

Warning aside, it prints:

object(SimpleXMLElement)#4 (1) {
  [0]=>
  string(6) "123456"
}
int(246912)
NULL
string(7) "246,912"

The explanation:

Most SimpleXML methods return objects that when cast to string, either implicitly or explicitly, display the corresponding node/attribute value.
number_format() does not cast to string because it expects a number.

Fix:

number_format((string)$value)

answered Nov 21, 2017 at 16:40

Álvaro González

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2 Comments

Hiigaran Over a year ago

Looks like the fix worked. Regarding error reporting, normally that's easy enough to do for most uses, but in this particular case when you're generating an image, how would you view those errors? Would you output to a file?

Álvaro González Over a year ago

I normally just hit Ctrl+U in the browser to see the source code.

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