How to graph time and date pairs?

Question

I'm trying to graph date and time data, but I have know idea how. I've heard of the libraries pandas and matplotlib, but I don't know how to graph time or date data, much less them together. Here is a sample dataset:

    x-axis       y-axis
Oct 17, 2017    19:38.00
Oct 14, 2017    19:06.05
Oct 7, 2017     19:12.00
Sep 30, 2017    19:37.15
Sep 27, 2017    21:37.00
Sep 22, 2017    21:26.65
Sep 20, 2017    21:35.55
Sep 8, 2017     21:30.56
Sep 1, 2017     21:21.20
Aug 22, 2017    23:56.05

It's just a list of datetimes? What are you hoping to achieve in plotting it? — Andy Hayden, Nov 03 '17 at 20:53
so you want to plot the dates against the times? that seems a strange thing to want to plot... — Andy Hayden, Nov 03 '17 at 21:09
it's for running, so I would like to be able to show the decreases in time — Peter S, Nov 03 '17 at 21:14

score 0 · Accepted Answer · answered Nov 03 '17 at 21:24

Once you convert columns to pandas date and timedelta (or seconds), that should be enough:

In [11]: df["x-axis"] = pd.to_datetime(df["x-axis"])

In [12]: df["y-axis"] = pd.to_timedelta(df["y-axis"].str.replace(".", ":")).astype('timedelta64[s]')

In [13]: df.plot(x="x-axis", y="y-axis")
Out[13]: <matplotlib.axes._subplots.AxesSubplot at 0x1131769e8>

How to graph time and date pairs?

1 Answers1