How to translate Unicode escape sequences to the Unicode character?

Question

I have a file with a lot of characters represented like this: \u05E2. (These are the actual characters in the file: backslash, lowercase u, and four hexadecimal digits.) Due to that, the file is impossible to read. Is there a way to translate the code to the actual symbol? (in the example above, ע).

Answer 1

If I understand you correctly, you have a file where certain characters are represented by their decimal value in the format \uXXXX, with X being any hexadecimal character but always 4, correct?

If so, you can transform those sequences into the actual values they represent by doing a clever search and replace. In this particular case, I would do:

:%s/\\u\(\x\{4\}\)/\=nr2char('0x'.submatch(1),1)/g

This translates to

:%s/      - start a search/replace command in the complete buffer
\\u       - Search for the characters \u
\(...\)   - remember the next chars
\x\{4\}   - 4 hexadecimal characters - they will be remembered and be available as submatch(1)
/         - replace each match by
\=        - evaluate the following to an expression
nr2char(  - return the character for the number given
'0x'      - put a '0x' in front of the number to force hexadecimal value
.         - append
submatch(1) - the hexadecimal number remembered above
)         - closing paren of nr2char()
/g        - replace for every occurrence in each line

While this will replace each occurrence of the pattern \u\x\x\x\x that does not necessarily mean, there will be a glyph available for that character. In such cases it could be shown as a blank square or a '?'.

Note, if you also have less than 4 or more than 4 hexadecimal characters after the \u (or you had an upper 'U' instead of the lower 'u') you would need to adjust the search pattern. This is left as an exercise to the reader.

See the help at :h sub-replace-special and :h nr2char() (among others)