Converting an underscored string to camelcase

Question

I would like to take a string containing underscores and convert it to CamelCase. I am attempting to do this using the stringstrings package. Here is my code:

\documentclass[11pt]{report}
\usepackage{amsmath}
\usepackage{stringstrings}
\begin{document}

\convertchar[q]{test_string}{\textunderscore}{ ??? }
\capitalizewords[q]{\thestring}
\noblanks{\thestring}

\end{document}

I am not sure what to put as the third argument to \convertchar to convert the underscores to spaces. I have tried ~, quad, and . They all produce strange errors. What can I use as the third argument, or, is there another way to obtain camelcase?

Answer 1

When chaining stringstrings commands, you should work with the encoded form (given by the [e] option) until the very last command:

\documentclass[11pt]{report}
\usepackage{amsmath}
\usepackage{stringstrings}
\begin{document}

\convertchar[e]{test_string}{_}{ }
\capitalizewords[e]{\thestring}
\noblanks[q]{\thestring}
\thestring

\end{document}

Basically, [e]-mode works like [q]-mode in that it does not produce any output, but makes sure that special characters (such as _) do not get expanded prematurely. This is generally required, if \thestring is fed into another stringstring command. The big benefit of this approach is that you can prevent \expandafter chains if composing string manipulation commands. §2 of the stringstrings manual explains this in detail.

Answer 2

Here is an easy way of substituting spaces for underscores in a string (with the xstring package).

\documentclass{article}

\usepackage{xstring}

\begin{document}

\newcommand\myStringWithUnderscores{Man_is_a_rational_animal_so_at_least_I_have_been_told}
\StrSubstitute{\myStringWithUnderscores}{_}{ }[\myStringWithSpaces]

% just for showing the results
\begin{tabular}{ll}
Original string & \texttt{\expandafter\detokenize\expandafter{\myStringWithUnderscores}}\\
Final string    & \texttt{\myStringWithSpaces}
\end{tabular}

\end{document}

As for converting to CamelCase, well, that's not specific enough for a computer, which wouldn't automatically know which letter to make uppercase/lowercase. I guess 'converting to CamelCase' is not something that can be easily automated to great effect, and you'll probably have to do it on a string-by-string basis.