When to use forEach(_:) instead of for in?

Question

As documented in both Array and Dictionary forEach(_:) Instance methods:

Calls the given closure on each element in the sequence<

Answer 1

I recently ran across a use case where using forEachwas preferable in a tangible way to for in. Let's say you want to remove all sublayers from a layer. A statement such as the below doesn't work as you need to unwrap the [CALayer]

for layer in self.videoContainerView.layer.sublayers!

If sublayers are nil, you will get a crash. This forces you to check to see if there are sublayers first. However, a forEach makes this much simpler as in the following:

self.videoContainerView.layer.sublayers?.forEach { $0.removeFromSuperlayer() }