使用大熊猫中的索引来绘制数据

我有一个熊猫-数据框架和使用 resample()计算手段(例如每日或每月的手段)。 这里有一个小例子。

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'])


A
2000-01-01 -1.210683
2000-01-02  2.242549
2000-01-03  0.801811
2000-01-04  2.353149
2000-01-05  0.359541


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


A
2000-01-31 -0.048088
2000-02-29 -0.094143
2000-03-31  0.126364
2000-04-30 -0.413753

现在如何绘制 monthly_mean

如何设法使用新创建的 DataFramemonthly_mean的索引作为 x 轴?

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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.

Try this,

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

Also,

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

monthly_mean.plot(y='A')

Uses index as x-axis by default.

  • When plotting line plots against the index, the simplest answer is to not assign any x or y.
  • This will plot lines for all numeric or datetime columns, without specifying y.
monthly_mean.plot()

enter image description here

  • 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()

enter image description here

Something like this, perhaps.

import requests
import pandas as pd
from pandas import DataFrame
import matplotlib.pyplot as plt
import seaborn as sns


# Intitialise data of lists
data = [{'Month': '2020-01-01', 'Expense':1000, 'ID':'123'},
{'Month': '2020-02-01', 'Expense':3000, 'ID':'123'},
{'Month': '2020-03-01', 'Expense':2000, 'ID':'123'},
{'Month': '2020-01-01', 'Expense':3000, 'ID':'456'},
{'Month': '2020-02-01', 'Expense':5000, 'ID':'456'},
{'Month': '2020-03-01', 'Expense':10000, 'ID':'456'},
{'Month': '2020-03-01', 'Expense':5000, 'ID':'789'},
{'Month': '2020-04-01', 'Expense':2000, 'ID':'789'},
{'Month': '2020-05-01', 'Expense':3000, 'ID':'789'}]
df = pd.DataFrame(data)
df

Then...

uniques = df['ID'].unique()


for i in uniques:
fig, ax = plt.subplots()
fig.set_size_inches(4,3)
df_single = df[df['ID']==i]
sns.lineplot(data=df_single, x='Month', y='Expense')
ax.set(xlabel='Time', ylabel='Total Expense')
plt.xticks(rotation=45)
plt.show()
    

enter image description here

enter image description here

enter image description here