Pandas df histo, format my x ticker and include empty

Question

I got this pandas df:

index      TIME
12:07      2019-06-03  12:07:28
10:04      2019-06-04  10:04:25
11:14      2019-06-09  11:14:25
...

I use this command to do an histogram to plot how much occurence for each 15min periods

df['TIME'].groupby([df["TIME"].dt.hour, df["TIME"].dt.minute]).count().plot(kind="bar")

my plot look like this:

How can I get x tick like 10:15 in lieu of (10, 15) and how manage to add x tick missing like 9:15, 9:30... to get a complet time line??

Answer 1

You can resample your TIME column to 15 mins intervalls and count the number of rows. Then plot a regular bar chart.

df = pd.DataFrame({'TIME': pd.to_datetime('2019-01-01') + pd.to_timedelta(pd.np.random.rand(100) * 3, unit='h')})
df = df[df.TIME.dt.minute > 15] # make gap

ax = df.resample('15T', on='TIME').count().plot.bar(rot=0)
ticklabels = [x.get_text()[-8:-3] for x in ax.get_xticklabels()]
ax.xaxis.set_major_formatter(matplotlib.ticker.FixedFormatter(ticklabels))

(for details about formatting datetime ticklabels of pandas bar plots see this SO question)