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').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?
Solution 1:
Try this,
monthly_mean.plot(y='A', use_index=True)
Solution 2:
You can use reset_index to turn the index back into a column:
monthly_mean.reset_index().plot(x='index', y='A')
Look at monthly_mean.reset_index() by itself- the date is no longer in the index, but is a column in the dataframe, which is now just indexed by integers. If you look at the documentation for reset_index, you can get a bit more control over the process, including assigning sensible names to the index.
Solution 3:
Also,
monthly_mean.plot(x=df.index, y='A')
Solution 4:
monthly_mean.plot(y='A')
Uses index as x-axis by default.
Solution 5:
-
When plotting line plots against the index, the simplest answer is to not assign any
xory. - This will plot lines for all numeric or datetime columns, without specifying
y
monthly_mean.plot()
- Only specify
y=if there are multiple columns and you want certain columns plotted - Or select the columns before plotting (e.g.
monthly_mean[[c1, c2, c5]].plot())
# sample data with multiple columns (5 x 5)
df = pd.DataFrame(np.random.random_sample((5, 5)))
# method 1: specify y
df.plot(y=[0, 2, 4])
# method 2: select columns first
df[[0, 2, 4]].plot()
