Changing all occurences of $x$ into X

Question

I would like to add a command to my document so that I could write 'X' in a document and it would be interpreted as '$x$' by compiler (because x is a mathematical variable that I use a lot). Can you help me?

Welcome to TeX.SE. Please tell us which LaTeX compiler -- pdflatex, xelatex, lualatex, or something else? -- and which document class you employ. — Mico, Nov 10 '18 at 20:41

score 2 · Answer 1 · answered Nov 10 '18 at 20:30

You cannot/should not just type X for translation. You should plan at least to type \X (better still \X{}). You will want this in the preamble of your document.

\newcommand{\X}{$x$}

Better still is below. This allows the math to be correct also in otherwise fragile commands.

\newcommand{\X}{\(x\)\relax}

The Find/Replace option in your editor is needed to make the changes in an existing document.

Find $x$  ... Replace with \X

Brasil · Answer 2 · 2018-11-10T23:08:40.670

1

I would suggest you to define the macro \def\X{\ensuremath{x}}. It will work both in the text and in the math mode as well. See the example below

You can show that three times \X\ raised to the second power is
$$
    (3\X)^2 = 9 \X^2
$$

You'll see that it outputs something similar to

You can show that three times x raised to the second power is

(3 x)² = 9 x²

edited Nov 10 '18 at 23:08

answered Nov 10 '18 at 21:55

Brasil

1,286

2

Please don't use $$, see https://tex.stackexchange.com/q/503 – samcarter_is_at_topanswers.xyz Nov 10 '18 at 21:57
What's the problem with it, @samcarter? – Brasil Nov 10 '18 at 21:58
See the link I added to my first comment – samcarter_is_at_topanswers.xyz Nov 10 '18 at 21:58
I've seen that link even before this post, @samcarter. I use latex since 2015 and yet I feel quite new and with low level of knowledge about it. But during all my experience, I have never faced problem with either $ or $$. I still don't understand why such alarm about the dollar symbols for math mode. – Brasil Nov 10 '18 at 22:02
2

A single $ sign for inline math is no problem at all (and I use it routinely), the problem is using $$ for display math. I think the most notable problems caused by this are inconsistent spacing and left alignment of display maths won't work. – samcarter_is_at_topanswers.xyz Nov 10 '18 at 22:09
Good. I will adopt the other methods like \( and \[. I already use \begin{equation} for enumerated equations. Thank you, @samcarter. – Brasil Nov 10 '18 at 22:15
2

No need to use \(, a single $ is fine for inline math, just don't use $$ – samcarter_is_at_topanswers.xyz Nov 10 '18 at 22:22
1

See also this post for the distinction between using \newcommand and \def. – Jeffrey J Weimer Nov 10 '18 at 22:56
1

Also note that the spaces after \Xare eaten in text mode, so the output in your example is not x raised but xraised – siracusa Nov 10 '18 at 23:05
3

zzz \X\ zzz doesn't actually save any characters over the simpler and quicker zzz $x$ zzz – David Carlisle Nov 10 '18 at 23:49

Changing all occurences of $x$ into X

2 Answers2