Custom labels for ybar plot?

Question

I'd like to make a plot where data is arranged in bars, but each bar has a custom label if it is greater than a thousand. For instance, instead of 18,000 the label would read "18k" and for 50 million the label would read "50M" instead of "5*10^7". For billions it would read "2.2G" instead of "2.2*10^9". I've tried without success to find some way to do this and have checked the Tikz manual and all of the number format options, but can't figure it out.

\begin{tikzpicture}
\begin{semilogyaxis}[
width=11.5cm,
height=7.5cm,
ybar,
ymin=0.1,ymax=1e10,
legend style={at={(0.5,-0.2)},
anchor=north,legend columns=-1},
symbolic x coords={
candybar,
CD,
car,
house,
mansion,
spaceshuttle
},
xtick=data,
nodes near coords,
point meta=rawy, 
nodes near coords align={vertical},
x tick label style={rotate=45,anchor=east},
ymajorgrids=true,
grid style = very thin
]
\addplot coordinates {
(candybar,0.50) 
(CD,15) 
(car,18e3) 
(house,250e3) 
(mansion,50e6)
(spaceshuttle,2.2e9)
};
\end{semilogyaxis}
\end{tikzpicture}

Answer 1

You can customize your nodes near coords key for your own needs. For example, if you use

nodes near coords={%
  \pgfmathfloatparsenumber{\pgfplotspointmeta}%
  \pgfmathfloattomacro{\pgfmathresult}{\F}{\M}{\E}%
  \pgfmathsetmacro\mypostfix{\E<=2?0:(\E<=5?"k":(\E<=8?"M":"G"))}%
  \pgfkeys{/pgf/fpu}%
  \pgfmathparse{(\pgfplotspointmeta< 1Y1.0e3] ?1:%False
  (\pgfplotspointmeta < 1Y1.0e6]? 1Y1.0e3]:%False
    (\pgfplotspointmeta<1Y1.0e9] ? 1Y1.0e6]:1Y1.0e9])))}%
  \pgfmathparse{\pgfplotspointmeta/\pgfmathresult}%
  \pgfmathprintnumber[fixed,1000 sep=]\pgfmathresult\mypostfix%
},

You would get

I've also noticed that the rounding is problematic (as usual) so there might some need to use rounding if you are using values like 999999.