Swift Style

Iterating Collections of Optionals

When looping over a collection whose components are optionals, prefer case let and optional sugar (the question mark) to conditional binding. These approaches save you a scope and offers top-level access to each non-nil item. The following example shows the simplicity you gain by adopting optional sugar:

for case let item? in array {  // yes
    // iterates through each non-nil item in array
    ...
}

for item in array { // no
    if let item = item {
        // iterates through each non-nil item in array
        ...
    }
}

When working with optional elements, apply flatMap to filter a collection. This approach converts the following array of optionals into a new collection of non-optional elements. ...