pgfplots: How to add names of the days of the week to dateplot?

Question

Assumed we have the following code:

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Minimum Working Example (MWE):

\documentclass{standalone}
\usepackage{pgfplots}
\usepackage{filecontents}
\usepgfplotslibrary{dateplot}

\begin{filecontents}{data.csv}
    Date;                   Value
    2019-04-01 12:00:00;    1
    2019-04-02 12:00:00;    2
    2019-04-03 12:00:00;    3
    2019-04-04 12:00:00;    4
    2019-04-05 12:00:00;    5
\end{filecontents}

\begin{document}
    \begin{tikzpicture}
        \begin{axis}[date coordinates in = x,
                     xmin                = 2019-04-02 12:00:00,
                     xticklabel          = \month-\day,
                     table/col sep       = semicolon]
                     \addplot table[x=Date,y=Value]{data.csv};
        \end{axis}
    \end{tikzpicture}%
\end{document}

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Screenshot of the result:

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Question:

• How can I replace the current numeric dates with weekdays names like Mon., Tue., Wed., Thu., Fri., Sat., Sun.?
• Is there an option available so pgfplots can calculate the corresponding names of the days of the week for each numeric date automatically by itself?

I want to avoid setting xtick labels = {Mon., Tue., Wed., ...} manually by hand for each tick.

Answer 1

Looks like you can use the macros provided by the pgfcalendar package to convert \year-\month-\day to Julian days (\pgfcalendardatetojulian), then to day of week (\pgfcalendarjuliantoweekday) and then print the corresponding weekday (\pgfcalendarweekdayshortname), all directly in xticklabel:

xticklabel          = \pgfcalendardatetojulian{\year-\month-\day}{\tmpCnt}\pgfcalendarjuliantoweekday{\tmpCnt}{\tmpCnt}\pgfcalendarweekdayname{\tmpCnt},

\newcnt\tmpCnt is required first.

I suggest also adding xtick distance=1 so you get just one tick per day.

\documentclass{standalone}
\usepackage{pgfplots}
\usepackage{filecontents}
\usepgfplotslibrary{dateplot}

\begin{filecontents}{data.csv}
    Date;                   Value
    2019-04-01 12:00:00;    1
    2019-04-02 12:00:00;    2
    2019-04-03 12:00:00;    3
    2019-04-04 12:00:00;    4
    2019-04-05 12:00:00;    5
\end{filecontents}
\newcount\tmpCnt
\begin{document}
    \begin{tikzpicture}
        \begin{axis}[date coordinates in = x,
                     xmin                = 2019-04-02 12:00:00,
                     xticklabel          = \pgfcalendardatetojulian{\year-\month-\day}{\tmpCnt}\pgfcalendarjuliantoweekday{\tmpCnt}{\tmpCnt}\pgfcalendarweekdayshortname{\tmpCnt},
                     xtick distance      = 1,
                     table/col sep       = semicolon]
                     \addplot table[x=Date,y=Value]{data.csv};
        \end{axis}
    \end{tikzpicture}%
\end{document}