BUG: xlim and ylim not restricting plot area

[regmibijay]

• [x] I have checked that this issue has not already been reported.

• [x] I have confirmed this bug exists on the latest version of pandas.

• [x] (optional) I have confirmed this bug exists on the master branch of pandas.

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Code Sample, a copy-pastable example

df = pd.read_csv(myfile) #contains 2 columns, Time in ms and Voltage in mV
xlabel = "Time in ms"
ylabel = "Volate in mV"
xlim = [0,120]
ylim = [0,8]
df.plot(x = "Time", xlabel= xlabel, ylabel=ylabel, xlim = xlim, ylim = ylim, kind="line")
plt.show()

Problem description

I am plotting a large dataset using dataframe.plot() in pandas. Dataset contains data in csv format. As per documentation, I specify xlimand ylim as arg in df.plot. Now the axes take the xlim and ylim values accordingly but the figure does not scale to these values and plot shows some part of of graph but not the area defined by 'xlim' and 'ylim'.

without xlim :
with xlim set :
sample files here: samples project: project

Expected Output

I want to plot only the specified area. In my example image it would be the spike.

Output of pd.show_versions()

INSTALLED VERSIONS ------------------ commit : f2c8480af2f25efdbd803218b9d87980f416563e python : 3.9.2.final.0 python-bits : 64 OS : Linux OS-release : 4.4.0-19041-Microsoft Version : #488-Microsoft Mon Sep 01 13:43:00 PST 2020 machine : x86_64 processor : byteorder : little LC_ALL : None LANG : en_US.UTF-8 LOCALE : en_US.UTF-8 pandas : 1.2.3 numpy : 1.20.2 pytz : 2021.1 dateutil : 2.8.1 pip : 21.0.1 setuptools : 52.0.0 Cython : None pytest : None hypothesis : None sphinx : None blosc : None feather : None xlsxwriter : None lxml.etree : None html5lib : None pymysql : None psycopg2 : None jinja2 : 2.11.3 IPython : 7.22.0 pandas_datareader: None bs4 : 4.9.3 bottleneck : None fsspec : None fastparquet : None gcsfs : None matplotlib : 3.4.1 numexpr : None odfpy : None openpyxl : 3.0.7 pandas_gbq : None pyarrow : None pyxlsb : None s3fs : None scipy : 1.6.2 sqlalchemy : None tables : None tabulate : None xarray : None xlrd : None xlwt : None numba : None

[rhshadrach]

I think it should be ylim=[0, 8e-6]. Although I'm confused on the y-axis being labeled by 1e-6 in your second plot.

[rhshadrach]

I'm not able to duplicate on master; with ylim=[0, 8] or ylim=[0, 8e-6]. For the former, I get a line indecipherable from y=0; for the latter I get the expected output:

[regmibijay]

after comment from @rhshadrach, I was successful in debugging what was happening. I was processing command line parameters with argparse and this behaviour seems to occur when the supplied xlim and ylim data have string elements and not int or float type. We should maybe either raise ValueError or convert passed data to int or float.

[rhshadrach]

Thanks for reporting back @regmibijay - I agree and think either are a workable solution, although I personally would lean toward raising if the values are not numeric. Would you be interested in submitting a PR to implement the patch?

[regmibijay]

I am working on this issue and will address with a PR soon!