Questions tagged [conditionals]

{conditionals} is about macros like \if and \ifx that may execute other macros depending on whether certain conditions are true or not. Popular packages are {etoolbox} and {ifthen}.

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6
votes
3answers
466 views

Safe test for an empty expanded macro argument?

How can I test in a safe way (i.e. without reserving tokens as explained here) if an expanded macro argument is empty?
5
votes
2answers
908 views

How to configure theorems depending on the document class?

I would like to have \newtheorem{teo}{Teorema}[chapter] if the book class is loaded but \newtheorem{teo}{Teorema}[section] if the article class is loaded. Can I do this with some sort of ...
1
vote
3answers
2k views

Detecting if inside \section

How can I make a conditional that checks if it is currently inside a \part, \chapter, or \section? IF inside sectioning = TRUE DO "This text is inside a section." ELSE DO "This text is not ...
22
votes
2answers
831 views

Show footnotes on odd pages only

I'm writing my thesis using the scrbook-class. Is it possible to display footnotes only on the odd (right) pages? This should mean that \footnote{something} should be collected on even pages and ...
18
votes
2answers
2k views

Automatically remove page number if document has only one page (but not if two)

I write a lot of documents (agreements) based on memoir with the article option. Normal pagestyleis plain (page number centered in the footer). Sometimes a document is only one page long, and a page ...
14
votes
1answer
903 views

Create Two PDF versions of Classroom slides from Single LaTeX file: Teacher and Student

Is there a way to create a single document that will process a LaTeX file in two different ways (different preambles) and produce two different outputs. Specifically, I want to produce a set of ...
11
votes
2answers
1k views

How can I check if the filename of a LaTeX document contains a string?

I am preparing a LaTeX beamer presentation for students. I am looking for a simple way to create two versions of my presentation. One version for the Students, which just contains the text of the ...
5
votes
1answer
1k views

Multilingual beamer presentations from a single souce?

I have a beamer presentation of which I have two language versions (german and english), more languages are upcoming. I keep both versions in one source and select the one to typeset with the comment ...
5
votes
5answers
2k views

new command with cases?

This has been answered here for text outputs with the use of \IfEqCase from the xstring package. But if I want to use the output as a value to set a parameter in a function, it fails. Here is my MWE: ...
1
vote
0answers
76 views

How to check if last displayed content was displaymath / minipage ends on displaymath?

Is there a way to check if a minipage ends with display math? Or more generally, if the line above was a displaymath? Background: I defined a command for a minipage-environment that fixes alot of ...
14
votes
3answers
996 views

How to ensure document total page numbers is a multiple of four?

I'm producing a document (book class) that will ultimately be produced using offset lithography. It's therefore useful to ensure the total number of pages is a multiple of four by adding as many blank ...
12
votes
2answers
838 views

Missing Item number in enumerate

You would think that I would know better than to mess with an egreg solution, but in my defense I used a DavidCarlisle solution from \setbox vs. \sbox and \savebox - What are the differences I need to ...
12
votes
1answer
324 views

How can I check if the current code is inside a tikzpicture?

I read the answer for this question (inside a environment) but I would like to know if there is something more specific. LaTeX keeps the current environment in the macro \@currenvir but how do the ...
11
votes
2answers
434 views

Is it possible to abort loading a package if it's too old?

I'm working on a package that has to work on both TeXlive 2009 (Ubuntu, so updating TeXlive is a nonstarter) and later versions, and I'd like to be able to use fontspec with LuaLaTeX if we're on ...
8
votes
2answers
798 views

How to check if a column type is defined?

Column types for tables can be defined and overwritten with \newcolumntype. I would like to know if a column type is already defined for an example which shall only be executed in the case where the ...
7
votes
5answers
530 views

A command which concatenates a string an arbitrary number of times

I'm trying to define a command \repeatstring{#1}{#2} which repeats the string #2 #1 times. Here is what I tried: (it is based on what I found in How to concatenate strings into a single command?) \...
6
votes
1answer
203 views

How to create two PDFoutput from the same source

I have a very long source file. I would like to prepare from this source two PDF files: PDF contains all of the source file PDF containing only a few, marked earlier parts of the source file. How I ...
6
votes
1answer
124 views

tabularx processes its body multiple times; how do I know which cycle I am in?

Assume that I enjoy setting my tables using an \itemized or list-like coding structure: \begin{mytabular}[.5\textwidth] \item head1 & head2% <-- header row \item abc & def \item ghi &...
5
votes
2answers
77 views

filecontents: select rows of group to display

I have a file that contains 1,000 rows of product data. I want to select only a specific product type to print in my document. Minimal code in main.tex: \documentclass{article} \usepackage{...
5
votes
1answer
159 views

Test if two things typeset identical results

I want to test if two somewhat arbitrary things typeset as exactly the same thing. For example I would like the test to tell me that abc is different from xyz, but is the same as \def\bar{abc}\bar. A ...
5
votes
1answer
471 views

Suppressing remarks when not needed

I have written some remarks in some of my works that are somewhat informal and repetitive in nature (mainly for my own clarification). I was wondering if there is a way of suppressing them when I don'...
3
votes
1answer
312 views

Biblatex: No \postnotedelim for citations that aren't numerals

When I am citing pages in books, I use the citation format (Author 1982:45) But when I am citing something like paragraphs or online data with an ID number (i.e. things that aren't a plain numeral ...
2
votes
1answer
305 views

How can I color the header, section, and subsection name according to the current section value?

I'm trying to make a document with multiple "themes." This involves changing the color of the headers, section names, and headers based on what the current section is. The colors I want to use are ...
1
vote
2answers
298 views

How to multiply compile according to selected tags?

I would like to do the following, by I am not sure how. Say I have a LaTeX file with series of annotations, each with zero or more "tags" (say, about their contents or the project they are related to)...
0
votes
1answer
843 views

Switch between different output versions compiled from the same LaTeX source [duplicate]

For programming in C, it is quite common to switch between creating debug- and release-versions by passing a command line argument to the compiler. I would like to have something similar for pdflatex....
25
votes
1answer
1k views

What is an \if?

I'm reading TeX by Topic, but in little chunks (rather than from first page to last) and just read the stuff on conditionals. I want to be sure that I understand what's going on when TeX starts ...
18
votes
1answer
2k views

Conditional pagebreak?

Is there a way I can have LaTeX insert a pagebreak, if the last line of the page is a certain string? e.g. \noindent \textsl{Solution}: thanks very much!
17
votes
3answers
3k views

Choosing styles conditionally in TikZ

I want to create a series of images that visualise a recursion tree as walked on by an algorithm. That means that different styles are applied to nodes depending on the step the algorithm is in, such ...
28
votes
4answers
2k views

Test success of write18

For the new version of my package and class standalone I like to call external programs: further (pdf)latex runs to optionally compile included standalone files, and to convert the resulting PDF to ...
14
votes
1answer
55k views

LaTeX \if condition

I am using \if condition in a custom command in my LaTeX document. I would like to know where I can find some good explanation about \if command. I followed a Wikibooks \if page but it's just an ...
31
votes
6answers
30k views

What is \iffalse for?

So this is something I've wondered about for a while. What use is a conditional that always evaluates to false? I guess it's a neat way to "hide code from LaTeX" but apart from that, is it ever useful?...
28
votes
2answers
7k views

Difference between \newbool and \newtoggle from etoolbox package

Paul Gaborit's answer to How to detect if option provided via \tikzset uses \newbool to define a new boolean \booltrue to set a boolean, and \ifbool to perform a conditional operation all from the ...
19
votes
4answers
3k views

How to compare numbers with decimal point and logical OR operation?

I'm reading five values from external CSV file as [\sone, \stwo, \sthree, \sfour, \sfive]. Sample values could be [55.3, 89.0, 33.5, 40, 0.10]. Question : How to compare number with decimal points. ...
15
votes
3answers
9k views

How to make LaTeX ignore the contents of an environment?

I would like to make a \todo command and environment whose behavior changes depending whether I define a command \showtodos. A basic \todo command is simple to write: \ifthenelse{\isundefined{\...
11
votes
2answers
17k views

LaTeX “Variables” - \@varname

I'm currently in the process of writing my first document class file (a personalized resume class), and I want to get a better understanding of what exactly I'm doing. So, right now I'm setting up ...
11
votes
4answers
5k views

Logical String Length

How do I do a conditional 'if then else' statement, based on length of string being greater than (or less than, or equal) a specified value. For example, something Like \def\mystring{XYZ} \def\...
10
votes
2answers
367 views

Detect whether I'm in a \footnote?

How do I detect whether I'm in a \footnote environment or not?
17
votes
6answers
2k views

Checking if a number is a multiple of 4

Using etoolbox, ifthen, or another form of conditional checking, how can I check if a value is a multiple of 4? E.g. if the number is 4, 8, 12, 16, etc., then it returns "true".
15
votes
3answers
2k views

How to implement a command that checks for loaded packages?

I use the following code to check if a package is loaded: \RequirePackage{ltxcmds} \newcommand{\IfPackageLoaded}[2]{\ltx@ifpackageloaded{#1}{#2}{}} However, sometimes I want to check if more than ...
13
votes
1answer
933 views

Biblatex: Print ISBN only if DOI is not defined

I have a large set of references and I in most cases do have either ISBN DOI DOI and ISBN I'd like to setup a filter that prints the ISBN only when the DOI does not exist. How can I set up a ...
13
votes
1answer
4k views

How to use mod operation in latex with tikz

I need something similar to \ifnum \j mod 2 = 0 rest of a number, but do not know how to do this in line 22. \documentclass{article} \usepackage{tikz} \usepackage[active,tightpage]{preview} \...
8
votes
3answers
946 views

How to include a second file only if environment variable is set?

I have a LaTeX document which exists in two versions, a short version and the long version. The long version has an additional chapter inserted in the middle of the document. What I want to do, is if ...
19
votes
1answer
2k views

testing for a documentclass option

I know that there are lots of similar question, but none of those have helped me so far - and I did google a lot. So my question is: I have a document class (emulateapj) which accepts a few options. ...
18
votes
2answers
3k views

Is a TeX macro defined?

I am looking for a way in TeX to check if a macro was defined. Currently I use a rather tangled way. I exploit a sort of side effect when comparing two macros via \ifx; this command returns: true, ...
18
votes
5answers
1k views

Test if token is a control sequence

Sometimes more complex (La)TeX macros test the next input token and branch dependent on its type. I'm aware how to test for catcodes and character codes, but sometimes I like to handle control ...
17
votes
2answers
485 views

Why does this simple \ifx test fail?

This should be easy, but I don't understand why the test below fails... I expected Hurrah! to be printed when the \currentchar count reaches 90 (i.e. the character code of Z). There must be some ...
12
votes
2answers
913 views

How to detect if option provided via \tikzset

I would like to be able to detect if a particular option has been provided via a \tikzset and issue a message based on that. The MWE yields: But once the conditional works (just a comment for now) ...
10
votes
1answer
830 views

Biblatex: Convert doi-url into doi field

I use biblatex and would like my bibliography to only include a DOI field, whenever there is DOI information available. This involves two things: Biblatex has to suppress the URL field whenever a DOI ...
8
votes
2answers
1k views

Expand command read from file

I have a file, that contains a list of latex commands each command per line. Now I want to read this file line per line and execute/expand the macros automatically. I tried the following but this only ...
8
votes
2answers
8k views

math conditionals using (if - else - fi) command

I saw these command when i searching sth. I wonder if we can increase numbers if conditions. it's like if{0} = a, if{1}=b, if{2}=c, if{3}=d etc. \newcommand{mycommand}[1]{ \if{#1 != 0} Some text, ...