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WoC: Detect non-iterable objects in foreach

https://www.flickr.com/photos/swedpix/36960629121/From time to time we use iterable objects, arrays, objects implementing the \Traversable interface (which iterators also do).

In the old days, real programmers didn’t check for data types, they set sort of canary flags like this:

This implements some sort of foreach {…} else {…} construct that PHP doesn’t have. Sure, it works. If you don’t turn on warnings, because if you do, you will be overwhelmed by warnings about foreach trying to act on a non-array/iterable object.

There is a solution: test your data type before running into the foreach! Yes, this means if you can not be 100% sure what sort of object you get, you have to enclose each and every foreach with an if construct. Since PHP 7.1 this block can make use of the is_iterable() function, which returns true, if the given parameter is any kind of iterable object:

For me this looks much better. The result is the same, but without warnings and the purpose is directly intelligible. The former example needs some thinking about the wtf factor of the code.

For PHP versions below 7.1 you can use some sort of polyfill function:

Thanks to the commentators of the PHP manual for this hint.