in pandas , add scatter plot to line plot

Question

I am trying to add a scatter plot to a line plot by using plandas plot function (in jupyter notebook).

I have tried the following code :

import pandas as pd
import matplotlib.pyplot as plt
%matplotlib inline

# plot the line 
a = pd.DataFrame({'a': [3,2,6,4]})
ax = a.plot.line()

# try to add the scatterplot
b = pd.DataFrame({'b': [5, 2]})
plot = b.reset_index().plot.scatter(x = 'index', y = 'b', c ='r', ax = ax)
plt.show()

I also checked the following various SO answers but couldn't find the solution.

If anytone can help me, that ould be very appreciated.

EDIT:

somehow the accepted answers works, but i realise that in my case the reason it was not working might have to do with the fact i was using datetime.

like in this code, i cant see the red dots...

import pandas as pd
import matplotlib.pyplot as plt
from datetime import datetime as dt
%matplotlib inline

fig, ax = plt.subplots()
# plot the line 
a = pd.DataFrame({'a': [3,2,6,4]}, index = pd.date_range(dt(2019,1,1), periods = 4))
plot = a.plot.line(ax = ax)

# try to add the scatterplot
b = pd.DataFrame({'b': [5, 2]}, index = [x.timestamp() for x in pd.date_range(dt(2019,1,1), periods = 2)])
plot = b.reset_index().plot.scatter(x = 'index', y = 'b', c ='r', ax = ax)
plt.show()

Any idea whats wrong here?

set up your ax first. And use the `ax=ax` in both plot calls — user1558604, Dec 05 '19 at 17:23
@user1558604 Thx a lot. Could you give me the 2 or 3 lines of code that entails ? I find it confusing. — jim jarnac, Dec 05 '19 at 17:26
@jim , can you please explain the difference between the expected behavior and the wanted behavior? — Elegant Code, Dec 05 '19 at 17:26
@Quang Hoang well (in jupyter notebook) it simply doesnt show the plot with the line and scatter.. — jim jarnac, Dec 05 '19 at 17:26
It works in my notebook too. I'm assuming there is some other plot in the notebook. — Elegant Code, Dec 05 '19 at 17:27
@Elegant Code you mean if a plot already exists it wouldnt work ? Its a long time i havent used matplotlib... — jim jarnac, Dec 05 '19 at 17:28
@jimbasquiat, I believe that because of the magic Jupyter does behind the scenes, if you already have a plot set up previously, your new calls to df.plot() may or may not, add to the plot you're expecting to add to, unless you are explicit about which axes to add to, as user1558604 mentioned. I'm writing it into ans wer now. — Elegant Code, Dec 05 '19 at 17:32
@ElegantCode answer was what I was referring to jim. I have just submitted an edit (which you probably can't see yet) which will fix the overwritten ax issue. — user1558604, Dec 05 '19 at 17:41

score 4 · Accepted Answer · edited Oct 24 '21 at 18:49

4

This should do it (just add fig, ax = plt.subplots() in the beginning):

import pandas as pd
import matplotlib.pyplot as plt
%matplotlib inline

fig, ax = plt.subplots()

# plot the line 
a = pd.DataFrame({'a': [3,2,6,4]})
a.plot.line(ax=ax)

# try to add the scatterplot
b = pd.DataFrame({'b': [5, 2]})
plot = b.reset_index().plot.scatter(x = 'index', y = 'b', c ='r', ax = ax)
plt.show()

Edit: This will work for datetimes:

import matplotlib.pyplot as plt
from datetime import datetime as dt
# %matplotlib inline

fig, ax = plt.subplots()
# plot the line 
a = pd.DataFrame({'a': [3,2,6,4]}, index = pd.date_range(dt(2019,1,1), periods = 4))
plot = plt.plot_date(x=a.reset_index()['index'], y=a['a'], fmt="-")

# try to add the scatterplot
b = pd.DataFrame({'b': [5, 2]}, index = pd.date_range(dt(2019,1,1), periods = 2))
plot = plt.scatter(x=b.reset_index()['index'], y=b['b'], c='r')
plt.show()

edited Oct 24 '21 at 18:49

Trenton McKinney

56,955
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144
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answered Dec 05 '19 at 17:35

Elegant Code

678
6
18

thax, but then is it not overwritten by `ax = a.plot.line()` ? – jim jarnac Dec 05 '19 at 17:38
@jimbasquiat, ooopppsss, sorry about that. I changed it in my Jupyter notebook code but then I only copied the one line and added it to yours, instead of the whole code with the additional change user1558604 made. I initially copied your code into the answer and already indented it, and didn't want to have to reindent it again. Silly mistake. I'm glad user1558604 and you caught it quickly. – Elegant Code Dec 05 '19 at 18:10
@Elegant Code if you still have a bit of time, could you look at my edit ? (cant seem to find the issue when i use datetime on the x axis...) – jim jarnac Dec 05 '19 at 18:22
1

@jimbasquiat ,added support for datetime – Elegant Code Dec 05 '19 at 19:50

in pandas , add scatter plot to line plot

1 Answers1

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