Question

设为字符串字母数字，我想在找到数字时拆分它。

remove xs = [ x | x <- xs, not (x `elem` ",.?!-:;\"\'0123456789")]

我从那些数字和somne标点符号开始但我怎么能分割字符串，所以我给字符串"I go 25abc tomorrow 100!"->["I","go","abc","tomorrow"]！

Answer 1

> import Data.List.Split
> split (dropDelims . dropBlanks $ oneOf " 0123456789") "I go 25abc tomorrow 100!"
["I","go","abc","tomorrow","!"]

使用words两步法将起作用

> words $ map (\x -> if x `elem` ['a'..'z']++['A'..'Z'] then x else ' ') "I go 25abc tomorrow 100!"
["I","go","abc","tomorrow"]

这里我将过滤器的定义更改为只有alpha字符，如果不符合您的需要，您可以通过定义过滤掉的字符来反转if条件。

导入Data.Char(isAlpha)即可更改

x `elem` ['a'..'z']++['A'..'Z']

到isAlpha x

Answer 2

您可以定义这样的递归函数：

import Data.Char

split :: String -> [String]
split [] = []
split s =
  let -- Remove non alphabetic characters from front of list
      s' = dropWhile (not . isAlpha) s
      -- Split the list at the point where the first non-alphabetic
      -- character appears
      (xs,ys) = span isAlpha s'
      -- Recursively call split on the second list, while prepending 
      -- the first list.
  in  xs:(split ys)

以下是通过递归调用对测试字符串进行的操作：

s  = "I go 25abc tomorrow 100!"
s' = "I go 25abc tomorrow 100!"
xs = "I"
ys = " go 25abc tomorrow 100!"

s  = " go 25abc tomorrow 100!"
s' = "go 25abc tomorrow 100!"
xs = "go"
ys = " 25abc tomorrow 100!"

s  = " 25abc tomorrow 100!"
s' = "abc tomorrow 100!"
xs = "abc"
ys = " tomorrow 100!"

s  = " tomorrow 100!"
s' = "tomorrow 100!"
xs = "tomorrow"
ys = " 100!"

s  = " 100!"
s' = ""
xs = ""
ys = ""

请注意，这会将单词"abc4def"拆分为["abc", "def"]。

Answer 3

以下应该这样做。

splitWithoutNumbers :: String -> [String]
splitWithoutNumbers = map removeNumbers.words
                      where 
                      removeNumbers ""     = ""
                      removeNumbers (s:ss) | isNumber s = removeNumbers ss
                                           | otherwise  = s : removeNumbers ss

*Main> splitWithoutNumbers "I go 25abc tomorrow 100!"
["I","go","abc","tomorrow","!"]

Answer 4

import Data.Char
import Control.Monad
remove = words . filter (liftM2 (||) isAlpha isSpace)

Answer 5

下面的代码行将在找到数字

时拆分字符串

String [] strArr = str.split（“[0-9]”）;

从字符串haskell中删除数字

5 个答案: