parsing - 如何解析文本并提取整数

Question

我有这个Data.Text

"Check: Find max among: 70, 102, 271, 40"

如何从此文本中提取数字并对它们应用函数？

Answer 1

出于各种美学原因，我喜欢这种方法:

import qualified Data.Text as T
import Data.Text.Read
import Data.Either
import Data.Char
import Data.Text.IO as T

readNums :: T.Text -> [Int]
readNums =
  map fst .                 -- 5. extract the parsed numbers
  snd .  partitionEithers . -- 4. collect only the valid numbers
  map decimal .             -- 3. parse each substring as an number
  filter (not . T.null) .   -- 2. filter out empty strings (not necessary)
  T.split (not . isDigit)   -- 1. split on non-digits