将文本转换为Unicode转义序列 [英] Convert Text to Unicode Escape Sequence

问题描述

我有一个 Text 对象，其中包含一些拉丁字符，需要将这些拉丁字符转换为 \ u #### 格式的unicode转义序列，其中#为十六进制数字

I have a Text object that contains some number of Latin characters that needs to be converted to a unicode escape sequence of the format \u#### with # being hex digits

此处中所述，haskell可以轻松地将字符串转换为转义序列，反之亦然.但是，它将仅转到小数表示形式.例如

As described here, haskell easily converts strings to escape sequences and vice versa. However, it will only go to the decimal representation. For example,

> let s = "Ñ"
> s
"\209"

是否有一种方法可以指定转义序列编码以强制其以正确的格式吐出?即

Is there a way to specify the escape sequence encoding to force it to spit out in the correct format? i.e

> let s = encodeUnicode16 "Ñ"
> s
"\u00d1"

推荐答案

这是怎么回事:

import Text.Printf (printf)

encodeUnicode16 :: String -> String
encodeUnicode16 = concatMap escapeChar
  where
    escapeChar c
        | ' ' <= c && c <= 'z' = [c]
        | otherwise =
            printf "\\u%04x" (fromEnum c)

我ghci，您可以按以下方式使用它:

I ghci, you can use it as follows:

> putStrLn $ encodeUnicode16 "Ñ"
\u00d1

请注意，如果您不使用 putStrLn ，它将被转义两次:

Note that if you don't use putStrLn it will get escaped twice:

> encodeUnicode16 "Ñ"
"\\u00d1"

这是因为ghci将在命令前面隐式添加 print .

This is because ghci will implicitly add a print in front of the command.

编辑:我错过了您拥有 Text 而不是 String 的那部分.这是 Text 的相同代码:

Edit: I missed that part that you have a Text and not a String. Here's the same code for Text:

import Data.Text (Text)
import qualified Data.Text as T
import qualified Data.Text.IO as T
import Text.Printf (printf)

encodeUnicode16 :: Text -> Text
encodeUnicode16 = T.concatMap escapeChar
  where
    escapeChar c
        | ' ' <= c && c <= 'z' = T.singleton c
        | otherwise =
            T.pack $ printf "\\u%04x" (fromEnum c)

同样，您要使用 T.putStrLn 避免所有内容都双重转义.

Again, you want to use T.putStrLn to avoid double escaping everything.

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