iOS -- 代码优化-3. for循环优化

案例1

for index in 0..<array.count {
	guard let item = array[index] as? XXX else {
		continue
	}
	// do other
}

优化后

for (index, header) in array.enumerated() {
	guard let item = header as? XXX else {
		continue
	}
	// do other
}

案例2

优化前

var index = 0
var tempItems: [[ObjectProtocol]] = [ObjectProtocol]
for item in self.items {
	if index >= 3 {
		break
	}
	if let f = self.items.last as? [ObjectProtocol] {
		tempItems.append(f)
	}
	index += 1
}
self.items = tempItems

优化后

var tempItems: [[ObjectProtocol]] = []

for item in self.items.prefix(3) {
    if let f = item as? [ObjectProtocol] {
        tempItems.append(f)
    }
}

self.items = tempItems