3

I am currently using \StrLen{#1} inside my \newcommand. This works flawlessly for any common string written in latin alphabet.

"Hello" has string length of 5 for example. Problem is with chinese characters. String length of "容容" is 8 which is technically corrent, but I wasn't able to find multibyte alternative to StrLen which would return 2.

Note: I am using pdflatex.

Regards, Jan

Improve this question
3
  • Welcome to TeX.SX! Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document}.
    – Skillmon
    Commented Mar 8, 2018 at 22:46
  • if you used luatex or xetex then each unicode character would be a single token otherwise you need to count character tokens ignoring any above hex 80 and less than hex C0
    – David Carlisle
    Commented Mar 8, 2018 at 22:50
  • Can you please show how and why you're using \StrLen?
    – egreg
    Commented Mar 8, 2018 at 23:34

2 Answers 2

Reset to default
8

You can count the utf-8 start bytes so for example

enter image description here

\documentclass{article}
\usepackage[utf8]{inputenc}

\makeatletter
\def\zz#1{\zzz0#1\relax}
\def\zzz#1#2{%
\ifx\relax#2 \the\numexpr#1\relax
\else
\expandafter\zzz\expandafter{%
  \the\numexpr(#1+\ifnum\expandafter`\string#2<"80 1\else \ifnum\expandafter`\string#2>"BF 1 \else 0 \fi\fi
  \expandafter)\expandafter\relax\expandafter}%
\fi}
\begin{document}

\zz{容容}

\zz{abc}

\zz{¢Àïα}

\end{document}
Improve this answer
3
  • This is exactly the solution I need. Tested and it works!
    – Jan Vorisek
    Commented Mar 9, 2018 at 12:58
  • Note that this gives codepoints, not graphemes. These will be the same on PDFTeX (which does not support combining characters), but not necessarily in LuaTeX or XeTeX.
    – Davislor
    Commented Dec 10, 2020 at 21:29
  • @Davislor true although that is what (some) definitions of string length for a unicode string would expect.
    – David Carlisle
    Commented Dec 10, 2020 at 22:02
1

Just for the sake of variety, here's a LuaLaTeX-based solution.

enter image description here

\documentclass{article}
\newcommand\zz[1]{\directlua{tex.sprint(utf8.len("#1"))}}
\begin{document}
\zz{Hello}, \zz{容容}, \zz{¢Àïα}
\end{document}

If your TeX distribution is quite old (say, at least 4 years old as of late-2020), simply replace utf8.len with unicode.utf8.len to get the code to run.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .