Shift y labels, stop y labels being dropped

Question

I have a const plot with intervals on the y-axis. I'd like my y labels to be centered in each bar, as it would be if this were an xbar interval graph.

Also, and more importantly, I'd like more flexibility and control in the y label intervals. Can I, for instance, include every other interval, as in [0,.05) [.1,.15) etc., with that gap in between?

Finally, is there an easy way to make the last interval a closed bracket on both sides?

\documentclass{article}
\usepackage{pgfplots}


\begin{document}

\begin{tikzpicture}
    \begin{axis}[
   height=10cm,
        const plot,
        y tick label as interval=true,
        ytick=,
        yticklabel={$[\pgfmathprintnumber\tick, \pgfmathprintnumber\nexttick)$},
        enlargelimits=false,
        ymin=0,
        xmin=0
    ] 
\addplot [fill=blue,opacity=.6,draw=blue]
coordinates
{(0,0) (393,0.000) (93,0.050) (44,0.100) (49,0.150) (31,0.200) (32,0.250) (37,0.300) (52,0.350) (90,0.400) (30,0.450) (26,0.500) (11,0.550) (32,0.600) (31,0.650) (15,0.700) (33,0.750) (18,0.800) (25,0.850) (31,0.900) (162,0.950) (0,1)};
\end{axis}
\end{tikzpicture}


\end{document}

Answer 1

To get one label for each bar, you can set ytick=data. To get the closed interval, you can use an inline check to see if the upper bound of the bin is 1, using \ifdim\nexttick pt=1pt ] \else ) \fi (\ifdim needs the values it compares to have units, that's why we'll use pt). To make sure everything aligns nicely, you should use \pgfmathprintnumber[fixed, fixed zerofill]{...}, and print the square bracket using \leavevmode\rlap{]}\hphantom{)} (as egreg kindly told me).

To print only some labels, ordinarily you'd use ytick={0,0.1,...,1}, but in the case of interval ticks that doesn't do what you want it to (it would plot 0-0.1, 0.1-0.2, while you want 0-0.05,0.1-0.15), so we'll have to do something else: We can introduce a counter that is incremented for every tick, and at each tick we check whether the counter value is divisible by 2 (or 3 or whatever) using \pgfmathparse. If it is, we print the tick label, if it isn't we don't:

\documentclass{article}
\usepackage{pgfplots}


\begin{document}

\newcounter{ticknumber}
\setcounter{ticknumber}{1}
\makeatletter
\begin{tikzpicture}
    \begin{axis}[
   height=10cm,
        const plot,
        y tick label as interval=true,
        ytick=data,
        yticklabel={%
        \pgfmathtruncatemacro\isdivisible{Mod(\theticknumber,2)==0}
        \ifnum\isdivisible=1
         $[\pgfmathprintnumber[fixed, fixed zerofill]\tick, \pgfmathprintnumber[fixed, fixed zerofill]\nexttick\ifdim\nexttick pt=1pt \leavevmode\rlap{]}\hphantom{)} \else ) \fi$
        \fi
        \stepcounter{ticknumber}
        },
        enlargelimits=false,
        ymin=0,
        xmin=0
    ] 
\addplot [fill=blue,opacity=.6,draw=blue]
coordinates
{(0,0) (393,0.000) (93,0.050) (44,0.100) (49,0.150) (31,0.200) (32,0.250) (37,0.300) (52,0.350) (90,0.400) (30,0.450) (26,0.500) (11,0.550) (32,0.600) (31,0.650) (15,0.700) (33,0.750) (18,0.800) (25,0.850) (31,0.900) (162,0.950) (0,1)};
\end{axis}
\end{tikzpicture}


\end{document}