swift记录

let oldArray = [1,2,3,4,5,6,7,8,9,10]
        let newArray = oldArray.filter({$0 >= 4})
        NSLog("%@", newArray)

闭合和半闭合区间

for index in 1...5 {
            NSLog("------%d", index);
        }
        for index in 1..<5 {
            NSLog("------%d", index);
        }