24

I have a table that represents a timetable for bus, so each cell contains time of departure as hour followed by minute, both as two digits, but sometimes I don't have two digits,just one so I have to switch eg. from 12 4 -> 12 04. How is it possible?

lockstep
  • 250,273
Ion Morozan
  • 497

4 Answers4

31

You can define a macro as follows:

\newcommand\twodigits[1]{%
   \ifnum#1<10 0#1\else #1\fi
}

\twodigits{12}  % 12
\twodigits{4}   % 04
\twodigits{123} % 123

This macro is fully expandable.

If you also want to cut trailing zeros you can use:

\newcommand\twodigits[1]{%
   \ifnum#1<10 0\number#1 \else #1\fi
}

\twodigits{004} % 04

If you want to change a tabular cell from 12 4 to 12 04 without adding explicit macros you can use the collcell package to collect the cell content and feed it to a macro which splits the numbers by the space:

% preamble:
\newcommand\formatdate[1]{\formatdatei#1\relax}
\def\formatdatei#1 #2\relax{%
   \twodigits{#1} \twodigits{#2}%
}

\usepackage{collcell}

% later
\begin{tabular}{l>{\collectcell\formatdate}l<{\endcollectcell}}
   Bus date  & 12 4 \\
\end{tabular}

If you post a real usage example I can help me with more specific macros.

David Carlisle
  • 757,742
Martin Scharrer
  • 262,582
  • Thank you for response. Can you please take a look here? I've added the question before with a case usage, but someone suggested to post a different question regarding this problem. – Ion Morozan May 17 '12 at 10:46
  • @IonMorozan: In such cases always add a link to the other question in the new question. – Martin Scharrer May 17 '12 at 10:48
  • Yes you are right! It's is my third post on a forum, so I have to learn. Thank you for the feedback and by the way your solution works great for me. Thank you again! – Ion Morozan May 17 '12 at 10:51
  • @MarcoDaniel: Thanks for pointing this out. I wrote the answer under my Windows installation were I don't have LaTeX installed, so I couldn't test it right away. I added a version which handles this kind of input without an assignment. – Martin Scharrer May 17 '12 at 12:50
  • 1
    @MartinScharrer: I found the following definition in latex.ltx ;-) \def\two@digits#1{\ifnum#1<10 0\fi\number#1} – Marco Daniel May 17 '12 at 13:18
  • @MarcoDaniel: Yes I vaguely remembered that something like this exists. However, here it is ok to define an own version. You avoid the need for \makeatletter etc. and the OP learns about \ifnum. – Martin Scharrer May 17 '12 at 13:23
  • @MartinScharrer: Indeed. I looked into the file to find another definition ;-) – Marco Daniel May 17 '12 at 13:37
22

You can do that using the siunitx package

\documentclass[a4paper,twoside,10pt]{article}

\usepackage{siunitx}

\begin{document}
\num[minimum-integer-digits = 4]{123}
\num[minimum-integer-digits = 4]{4}
\end{document}

prints

0123 0004

or alternatively you can declare the option as default,

\documentclass[a4paper,twoside,10pt]{article}
\usepackage{siunitx}

\begin{document}
\sisetup{minimum-integer-digits = 4}
\num{12}
\num{34}
\end{document}
percusse
  • 157,807
Andreas Wallner
  • 1,514
  • 2
  • 11
  • 17
8

You can also use the xstring package to add the leading zero for single digits:

enter image description here

Code:

\documentclass{article}
\usepackage{xstring}
\newcommand*{\TwoDigit}[1]{%
    \IfStrEqCase{#1}{%
        {1}{0}%
        {2}{0}%
        {3}{0}%
        {4}{0}%
        {5}{0}%
        {6}{0}%
        {7}{0}%
        {8}{0}%
        {9}{0}%
    }#1%
}%
\begin{document}
123 $\to$ \TwoDigit{123}

12 $\to$ \TwoDigit{12}


2 $\to$  \TwoDigit{2}
\end{document}
Community
  • 1
Peter Grill
  • 223,288
8

You can use LaTeX's internal \two@digit for formatting:

enter image description here

\documentclass{article}
\makeatletter
\newcommand{\twodigit}[1]{\two@digits{#1}}
\makeatother
\begin{document}

\twodigit{12} \par % 12
\twodigit{4} \par  % 04
\twodigit{123}     % 123

\end{document}
Werner
  • 603,163