Question

I’ll give an example, it’s will be more straight to the point :

I’m working with coordinates and I want to filter the coordinates that do not belong to a set around the picked coordinate. Here for the latitude for instance :

$latitude = 4.3999291;

Basically, I have an array of latitudes, $array_latitudes, and I want to test each one to know if they belong to a range around $latitude.

What I’ve done so far :

$set = range($latitude-0.2, $latitude+0.2, 0.0000001);
foreach ($array_latitudes as $lat){
    if (in_array($lat, $set)){
        echo $lat;
    }
}

So the issue is, you guessed it, about the performance… It takes a really long time to create an array of values of a 10^-7 range !

My question, then, is : “Is there a simpler and more efficient way to return the latitudes in $array_latitudes which belong to the set [$latitude-0.2, $latitude+0.2] with a precision of 10^-7 ?”

Thanks all 🙂

Answer 1

Could you not just test

if (abs($lat - $latitude) <= 0.2) {
  echo $lat;
}

?