最近做專案的時候，有個迴圈操作刪除陣列的元素剛開始是這麼寫的。

for (index, item) in list.enumerate() {

// 如果裡邊有刪除操作，會有bug，不信你測測。一直顯示陣列越界

}

for item in list {

// 改良之後的寫法，親測沒問題Bug，也符合swift的寫法
        var array = ["1","2","3","4","5","6"]
        for item in array {
         if  let index = array.index(of: item)) {
                if item == "1" {
                    array.removeAtIndex(index)
                }
                if item == "5" {
                    array.removeAtIndex(index)
                }
            }
        }
        print(array)