[FIXED] Trying to connect scatter plotted datetimes gives me tz error from matplot

Issue

I want to connect the orange dots to the blue dots.

Data Used: (pulled it using CSV lib)

handler,first_test,handler_arrived
hvvm-02,7/15/2020,1/26/2020
hvvm-03,4/8/2020,1/26/2020
hvvm-04,5/27/2020,1/26/2020
hvvm-07,7/8/2020,1/26/2020
hvvm-09,2/26/2020,1/7/2020
hvvm-10,2/26/2020,1/7/2020
hvvm-11,7/1/2020,1/6/2020
hvvm-12,7/15/2020,1/6/2020

I convert a list of strings to datetimes

first_test = [dt.datetime.strptime(date, '%m/%d/%Y').date() for date in first_test]
handler_arrive = [dt.datetime.strptime(date, '%m/%d/%Y').date() for date in handler_arrive]

Then I plot them:

scat1 = ax.scatter(first_test, handlers)
scat2 = ax.scatter(handler_arrive, handlers)

I tried to connect them by calling: plt.plot_date(first_test, handler_arrive)

and this

plt.plot(first_test, handler_arrive, '-o')

I get this error

  File "C:\Users\user\PycharmProjects\handler_enablement\venv\lib\site-packages\matplotlib\dates.py", line 342, in _from_ordinalf
dt = dt.astimezone(tz)
TypeError: tzinfo argument must be None or of a tzinfo subclass, not type 'UnitData'

So I try plt.plot_date(first_test, handler_arrive, tz=None) (to try to shush the error) didn't work

At no point have I set a timezone nor did I need to, because I never got this error when messing with the datetimes before, so idk why this error occurs now. It must be how I am trying to connect the dots with that function call. It doesn't seem right...

I have tried these and they did not work

pandas scatter plotting datetime

Matplotlib connect scatterplot points with line - Python

What am I missing?

Solution

Thanks for posting your data. Below is the dataframe that I created based on the tab delimited version:

    handler first_test  handler_arrived
0   hvvm-02 7/15/2020   1/26/2020
1   hvvm-03 4/8/2020    1/26/2020
2   hvvm-04 5/27/2020   1/26/2020
3   hvvm-07 7/8/2020    1/26/2020
4   hvvm-09 2/26/2020   1/7/2020
5   hvvm-10 2/26/2020   1/7/2020
6   hvvm-11 7/1/2020    1/6/2020
7   hvvm-12 7/15/2020   1/6/2020

Then, I created the data series to use for plotting using mostly your code:

handlers = df['handler']
first_test = [dt.datetime.strptime(date, '%m/%d/%Y').date() for date in df['first_test']]
handler_arrive = [dt.datetime.strptime(date, '%m/%d/%Y').date() for date in df['handler_arrived']]

When I did the scatter plot with plt.plot_date(first_test, handler_arrive), I did not incur any error. Could the (delta: xx days) part be a complication in the plotting?

I also did a plot connecting the two groups of dates using the following code:

plt.rcdefaults()
fig, ax = plt.subplots()
scat1 = ax.scatter(first_test, handlers)
scat2 = ax.scatter(handler_arrive, handlers)
for i in range(len(first_test)):     
    plt.plot([first_test[i],handler_arrive[i]], [handlers[i],handlers[i]], color='black')

The result is below:

For reference, please see Matplotlib python connect two scatter plots with lines for each pair of (x,y) values?

Hope it is helpful!

Answered By - Life is Good