我有一些可以编译和工作的代码。然后一些没有。我担心的是第一个版本太臃肿以至于在运行太大的参数时崩溃了，所以我写了第二个版本时考虑到了性能。第二个版本甚至没有编译。请指教。
import System.Environment (getArgs)
import Data.List (nub)
import System.Random
import Control.Applicative ( (<$>) )
import Control.Monad (replicateM)
randomItem :: [a] -> IO a
randomItem xs = (xs!!) <$> randomRIO (0, length xs - 1)
genFromMask :: [String] -> IO String
genFromMask = mapM randomItem
genMeSome :: [String] -> Int -> IO [String]
genMeSome mask n = do
glist <- replicateM (n*10) (genFromMask mask)
return $ take n $ nub glist
writeIt :: FilePath -> Int -> [String] -> IO ()
writeIt fi n mask = do
glist <- genMeSome mask n
writeFile fi $ unlines glist
maj :: String
maj = ['A'..'Z']
numa :: String
numa = ['0'..'9']
-- | Certaines regions n'utilisent aucune des plages libres
genBra :: [String]
genBra = ["VWXYZ",maj,maj," ",numa,numa,numa,numa]
genAus :: [String]
genAus = [maj,maj,maj," ",numa,numa,numa]
main :: IO ()
main = do
args <- getArgs
case args of
(mo:fi:n:_) -> case mo of
"aus" -> writeIt fi (read n) genAus
"bra" -> writeIt fi (read n) genBra
_ -> error "country is not supported"
_ -> error "wrong input, format is: genLicensePlate country file number"
这是第二个：
import System.Environment (getArgs)
import System.Random
import Crypto.Random.AESCtr (makeSystem)
import Control.Applicative ( (<$>) )
import qualified Data.Vector as V
import qualified Data.Text as T
import qualified Data.Text.IO as T
nubV :: V.Vector a -> V.Vector a
nubV va
| V.null va = V.empty
| V.any (== headV) tailV = nubV tailV
| otherwise = headV `V.cons` nubV tailV
where
headV = V.head va
tailV = V.tail va
randomItem :: RandomGen g => g -> V.Vector a -> (a,g)
randomItem g xs =
(xs V.! fst shamble, snd shamble)
where
shamble = randomR (0, V.length xs - 1) g
genFromMask :: RandomGen g => g -> V.Vector (V.Vector a) -> V.Vector a
genFromMask g xs =
if V.null xs
then V.empty
else fst paket `V.cons` genFromMask (snd paket) (V.tail xs)
where
paket = randomItem g (V.head xs)
genMeSome :: RandomGen g => g -> V.Vector (V.Vector a) -> Int -> V.Vector (V.Vector a)
genMeSome g mask n =
V.take n $ nubV $ V.replicateM (n*10) (genFromMask g mask)
writeIt :: RandomGen g => g -> FilePath -> Int -> V.Vector (V.Vector a) -> IO ()
writeIt g fi n mask =
T.writeFile fi $ T.unlines $ T.pack $ V.toList (V.map V.toList $ genMeSome g mask n)
maj = V.fromList ['A'..'Z']
num a = V.fromList ['0'..'9']
vspa = V.fromList " "
vtir = V.fromList "-"
-- | Certaines regions n'utilisent aucune des plages libres
genBra = V.fromList [static,maj,maj,vspa,numa,numa,numa,numa]
where
static = V.fromList "VWXYZ"
genAus = V.fromList [maj,maj,maj,vspa,numa,numa,numa]
main :: IO ()
main = do
g <- makeSystem
args <- getArgs
case args of
(mo:fi:n:_) -> case mo of
"aus" -> writeIt g fi (read n) genAus
"bra" -> writeIt g fi (read n) genBra
_ -> error "country is not supported"
_ -> error "wrong input, format is: genLicensePlate country file number"
我正在尝试生成假车牌，以填充匿名数据库。
编辑1：
以下是错误：
genLicensePlate.hs:22:12:
No instance for (Eq a)
arising from a use of `=='
In the first argument of `V.any', namely `(== headV)
In the expression: V.any (== headV) tailV
In a stmt of a pattern guard for
an equation for `nubV':
V.any (== headV) tailV
genLicensePlate.hs:48:52:
Couldn't match expected type `Char' with actual type
Expected type: V.Vector Char
Actual type: V.Vector [a]
In the first argument of `V.toList', namely
`(V.map V.toList $ genMeSome g mask n)'
In the second argument of `($)', namely
`V.toList (V.map V.toList $ genMeSome g mask n)'
编辑2：
所以总体思路是使用掩码生成随机字符串。像 myFunc g [['A'..'Z'],['A'..'Z']] 给出 AA 或 ZZ 或 BA 或 FG 等......然后我使用这个函数来制作很多这些字符串基于掩码。之后，我删除重复项并根据需要获取尽可能多的数量（因为即使有重复项我也可以生成 10 倍于所要求的数字）。最后我把它放在一个文件上。
我希望它更清楚。
亲切的问候，萨尔