我想爲MyString = "ab"
和n = 4
做到這一點在Haskell哈斯克爾迭代內涵
結果應該是>
["aaaa","aaab","aaba","aabb","abaa","abab","abba","abbb","baaa","baab","baba","babb","bbaa","bbab","bbba","bbbb"]
我想爲MyString = "ab"
和n = 4
做到這一點在Haskell哈斯克爾迭代內涵
結果應該是>
["aaaa","aaab","aaba","aabb","abaa","abab","abba","abbb","baaa","baab","baba","babb","bbaa","bbab","bbba","bbbb"]
replicateM 4 "ab"
給你要求什麼。您可以從Control.Monad
導入。
值得注意的是,這是使用列表monad,所以這是一般類型Monad m => Int - > ma - > m [int]的特例'Int-> [a] - > [[a]]'一]'。 –
如果你想寫你的自我,你可以做以下事情。
seq i xs | i > 0 = [x:ys | x <- xs, ys <- seq (i-1) xs]
| otherwise = [[]]
我們更有可能能夠幫助你,如果你需要一個在裂縫問題自己和[描述你已經嘗試過什麼(http://whathaveyoutried.com)。檢查堆棧溢出[問題清單](http://meta.stackexchange.com/questions/156810/stack-overflow-question-checklist)以獲取有關詢問正確問題的更多信息。祝你好運,快樂的編碼! –