使用大量数据点绘制时间序列matplotlib

Question

I want to plot a time series for a dataset which has data for 12 months. However the data is recorded for every hour of every day for the 12months. The whole dataset is over 8000 datapoints. The data is in the following format

        Date   Time  Energy
0 2014-01-01   1     1118.1
1 2014-01-01   2     1233.2
2 2014-01-01   3     1278.2
.     .        .      .  
23 2014-01-01  24    1125.3
24 2014-01-02  1     1213.3
.    .         .      .

When I plot it like this

plt.plot(energy['Date'], energy['Energy'])
plt.xlabel('Date')
plt.ylabel('Energy')

I get the following output

This graph doesn't make much sense because I cant observe any trends. I instead want to plot the average energy for each day. Any other suggestions about how to plot this time series in such a way that I observe any trends is welcome

Answer 1

You need groupby with aggregating mean first:

energy = energy.groupby('Date')['Energy'].mean()

and then Series.plot :

energy.plot()

All together:

energy.groupby('Date')['Energy'].mean().plot()

Answer 2

IIUC:

you need to sort

energy = energy.sort_values(['Date', 'Time'])
plt.plot(energy['Date'], energy['Wind Generation'])
plt.xlabel('Date')
plt.ylabel('Energy')
plt.autofmt_xdate()