[python] Use index in pandas to plot data

I have a pandas-Dataframe and use resample() to calculate means (e.g. daily or monthly means). Here is a small example.

import pandas as pd  
import numpy as np

dates = pd.date_range('1/1/2000', periods=100)
df = pd.DataFrame(np.random.randn(100, 1), index=dates, columns=['A'])

monthly_mean = df.resample('M', how='mean')

How do I plot the monthly_mean now? How do I manage to use the index of my new created DataFrame monthly_mean as the x-axis? Thanks in advance.

Also,

monthly_mean.plot(x=df.index, y='A')

monthly_mean.plot(y='A')

Uses index as x-axis by default.

Try this,

monthly_mean.plot(y='A', use_index=True)

Marius's answer worked perfectly for me:

df.reset_index() sets the index as the first column, with the column label "index." You can now use the index as an axis for plotting, as described in his answer:

monthly_mean.reset_index().plot(x='index', y='A')

However, this does not change the original dataframe. The original dataframe will be unchanged unless it is set using df = df.reset_index().

example:

df.reset_index()
print(df)

        COF    TSF    PSF
3.0   0.946  0.914  0.966
4.0   0.963  0.940  0.976
6.0   0.978  0.965  0.987
8.0   0.989  0.984  0.995
10.0  1.000  1.000  1.000
12.0  1.004  1.013  1.009
15.0  1.013  1.026  1.012
17.0  1.019  1.037  1.017
20.0  1.024  1.045  1.020
25.0  1.030  1.057  1.026
30.0  1.034  1.065  1.030
35.0  1.037  1.069  1.031
40.0  1.037  1.068  1.030
60.0  1.037  1.068  1.030

df = df.reset_index()
print(df)

    index    COF    TSF    PSF
0     3.0  0.946  0.914  0.966
1     4.0  0.963  0.940  0.976
2     6.0  0.978  0.965  0.987
3     8.0  0.989  0.984  0.995
4    10.0  1.000  1.000  1.000
5    12.0  1.004  1.013  1.009
6    15.0  1.013  1.026  1.012
7    17.0  1.019  1.037  1.017
8    20.0  1.024  1.045  1.020
9    25.0  1.030  1.057  1.026
10   30.0  1.034  1.065  1.030
11   35.0  1.037  1.069  1.031
12   40.0  1.037  1.068  1.030
13   60.0  1.037  1.068  1.030

See: DataFrame.reset_index and DataFrame.set_index