Sometimes, we require to check the given argument or string is URL or not, as specially i did need to check image column is url or not like i give you example how to do this. If you also need to do this then you can use filter_var().
Example:
if(filter_var($imagePath, FILTER_VALIDATE_URL) === FALSE){
print_r("Not valide URL");
}else{
print_r("valide URL");
}