Errors with Yelp API output

Question

I am trying to do something with Yelp API2

$response = json_decode($data);

which returns data in a PHP object format that looks something like this:

I want to output a few results using limit:

$limit = (isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10);

for ($x = 0; $x <= $limit; $x++) { 

}

The output is just fine but I also keep getting the following errors for each iteration of the loop and every value:

Notice: Undefined offset: 10 in /mypath/YelpTest.php on line 94 Notice: Trying to get property of non-object in /mypath/YelpTest.php on line 94

And I have on such line is:

echo $response->businesses[$x]->name;

What am I missing?

Dimitrios Desyllas · Answer 1 · 2016-03-12T10:52:50.253

0

Try with this piece of code:

foreach($response->businesses as $key=>$r)
{
 if($key>$limit) break;
 echo $r->name //May need to do some var_dumps in order to see what you get
}

edited Mar 12 '16 at 10:52

answered Mar 06 '16 at 13:12

Dimitrios Desyllas

6,470
6
43
106

Why you added if($r>$limit) break; in foreach? What you don't have any alternative or this is the best practice? – itzmukeshy7 Mar 11 '16 at 05:35
With tihs Implementation if $response->businesses has less data than limit it will stop traversing the array by itself. – Dimitrios Desyllas Mar 12 '16 at 10:52
Definitely by why we are adding an extra condition in every iteration if we can do the same with a single statement; see my answer; :) – itzmukeshy7 Mar 14 '16 at 05:03

Wyatt McGuire · Answer 2 · 2016-03-07T18:56:19.873

0

It looks like your defaulting the limit to 10 however there must only be 9 objects in the result set. The Notice: Undefined offset: 10 is telling you that there's no index for 10 in the $response->businesses array. The Notice: Trying to get property of non-object is telling you that $response->businesses[10] is null, which does not have any properties that can be read.

Instead of hard-coding a value, try reading the size of the array:

$limit = (isset($_POST['displayLimit']) ? $_POST['displayLimit'] : count($response->businesses);
for ($x = 0; $x <= $limit; $x++) { 
    ...

edited Mar 07 '16 at 18:56

answered Mar 07 '16 at 18:10

Wyatt McGuire

477
3
9

What if user enters a value greater than count($response->businesses) for $_POST['displayLimit'] – itzmukeshy7 Mar 11 '16 at 05:33
Good point. could replace that count($response->businesses) with min([count($response->businesses), $_POST['displayLimit']]) – Wyatt McGuire Mar 14 '16 at 03:03

Ronin · Accepted Answer · 2016-03-11T04:15:16.487

You are trying to get 10th element from array having only, for example, 9 elements; you do not rely on target array size which can be lesser than your limit.

If I were trying to get limited amount of records, I would get a slice from the $response->businesses and perform foreach through the slice:

$limit = isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10;

foreach (array_slice($response->businesses, 0, $limit) as $business) {
    echo $business->name;
}

The array_slice function has a good feature: when the $limit is greater than total count of array elements (starting from $offset, the second parameter of the function) it returns only available elements. For example, if you do array_slice([1, 2, 3, 4], 0, 100), it returns [1, 2, 3, 4] — limit is 100, but array has only 4 elements, so they all are returned and no any elements are added to array while slicing.

Another way:

$limit = isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10;

$counter = 0;

foreach ($response->businesses as $business) {
    echo $business->name;

    $counter++;

    if ($counter >= $limit) {
        break;
    }
}

Here I just break foreach loop when limit is reached. And I will have no errors when I have less than $limit array elements.

Another one approach which is inherited from your code:

$limit = isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10;

for ($x = 0; $x < $limit; $x++) {
    if (!array_key_exists($x, $request->businesses)) {
        // We have reached the end of $request->businesses array,
        // so break "for" loop.
        break;
    }

    echo $business->name;
}

In any case, you should rely on the array's size because it has chances to be lesser than $limit which will lead you to some errors.

Why you are checking it in every loop if (!array_key_exists($x, $request->businesses)) {... ? — itzmukeshy7, Mar 11 '16 at 05:34
@itzmukeshy7 Umm... To make sure that `$request->businesses[$x]` is exists. :) It's because `for ($x = 0; $x < $limit; $x++)` does not rely on `$request->businesses` size at all. So, we need to make sure if array key `$x` exists therefore array has a value under that index. — Ronin, Mar 11 '16 at 05:48
But why we are making it complex when we can do it just by updating the $limit with count($response->businesses) as per my answer — itzmukeshy7, Mar 11 '16 at 05:49
@itzmukeshy7 But also, why we are making it complex at all by calculating limits intersection? We may just perform a slice and do not worry about other things (see first example in my answer). — Ronin, Mar 11 '16 at 06:01

score 0 · Answer 4 · answered Mar 11 '16 at 05:43

You have this

$limit = (isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10);

Add one more condition after it

$returnedBusinesses = count($response->businesses);
$limit = (($limit > $returnedBusinesses)?$returnedBusinesses:$limit);

One more thing the for loop condition

NOW

for ($x = 0; $x <= $limit; $x++) {

AFTER

for ($x = 0; $x < $limit; $x++) {

Remove equal check because we are stating from 0 not 1.

Errors with Yelp API output

4 Answers4