How to plot multiple pandas columns on the y-axis of line graph

问题

I have dataframe total_year, which contains three columns (year, action, comedy) .

total_year

I want to plot the year column on the x-axis, and action & comedy both on the y-axis.

How can I plot two columns (action and comedy) on y-axis?

My code plots only one column on y-axis.

total_year[-15:].plot(x='year', y='action', figsize=(10,5), grid=True)

回答1:

Pandas.DataFrame.plot() per default uses index for plotting X axis, all other numeric columns will be used as Y values.

So setting year column as index will do the trick:

total_year.set_index('year').plot(figsize=(10,5), grid=True)

回答2:

Several column names may be provided to the y argument of the pandas plotting function. Those should be specified in a list, as follows.

df.plot(x="year", y=["action", "comedy"])

Complete example:

import matplotlib.pyplot as plt
import pandas as pd

df = pd.DataFrame({"year": [1914,1915,1916,1919,1920],
                   "action" : [2.6,3.4,3.25,2.8,1.75],
                   "comedy" : [2.5,2.9,3.0,3.3,3.4] })
df.plot(x="year", y=["action", "comedy"])
plt.show()

回答3:

• It's only necessary to specify a column to the x parameter, when using pandas.DataFrame.plot.
• The caveat is, the rest of the columns with numeric values will be used for y.
  • The following code contains extra columns to demonstrate. Note, 'date' is left as a string. However, if 'date' is converted to a datetime dtype, the plot API will also plot the 'date' column on the y-axis.
• If the dataframe includes many columns, some of which should not be plotted, then specify the y parameter as shown in this answer, but if the dataframe contains only columns to be plotted, then specify only the x parameter.

import pandas as pd

# test data
data = {'year': [1914, 1915, 1916, 1919, 1920],
        'action': [2.67, 3.43, 3.26, 2.82, 1.75],
        'comedy': [2.53, 2.93, 3.02, 3.37, 3.45],
        'test1': ['a', 'b', 'c', 'd', 'e'],
        'date': ['1914-01-01', '1915-01-01', '1916-01-01', '1919-01-01', '1920-01-01']}

# create the dataframe
df = pd.DataFrame(data)

# display(df)
   year  action  comedy test1        date
0  1914    2.67    2.53     a  1914-01-01
1  1915    3.43    2.93     b  1915-01-01
2  1916    3.26    3.02     c  1916-01-01
3  1919    2.82    3.37     d  1919-01-01
4  1920    1.75    3.45     e  1920-01-01

# plot the dataframe
df.plot(x='year', figsize=(10, 5), grid=True)

回答4:

All the independent/feature variable can be plotted with deendent(outcome-Y ) variable using the below mentioned loop and code based on the type of feature variable, whether that is object/int64/float64.

In this case Feature_col_X1 ( contains feature list ) and Target_col_Y1 is the target one, I am passing this in a defined function and I can get all the plot for 20 features to the 1 out

def plotforallvariables(Feature_col_X1,Target_col_Y1):
    for i in range(len(Feature_col_X1)):
        idx=Feature_col_X1[i]


        try:

            if data[idx].dtype =='O':
                #print('categorical')
                #%matplotlib inline
                #print(idx,'in X axis and also',Target_col_Y1 ,'in Y axis')




    pd.crosstab(data[idx],data[Target_col_Y1]).plot(kind='bar')
                #x=r'idx,'in X axis and also',Target_col_Y1 ,'in Y axis'
                #plt.title('x')
                #print(data[idx])
                #print(data[Target_col_Y1])
                #plt.xlabel(data[idx])
                #plt.ylabel(data[Target_col_Y1])

            elif data[idx].dtype =='int64':
                #ax = plt.gca()
                #data.plot(kind='line',x=data[idx],y=data[Target_col_Y1])
                pd.crosstab(data[idx],data[Target_col_Y1]).plot(kind='line')
                #data.plot.scatter(x=data[idx],y=data[Target_col_Y1])
                #plt.show()
                #print('integer')


            elif data[idx].dtype =='float64': 
                #print('float')
                pd.crosstab(data[idx],data[Target_col_Y1]).plot(kind='line')
                #data.plot(kind='line',x=data[idx],y=data[Target_col_Y1])

        except (ValueError,KeyError):
            print('skip error')

plotforallvariables(Feature_col_X,Target_col_Y)

来源：https://stackoverflow.com/questions/47775220/how-to-plot-multiple-pandas-columns-on-the-y-axis-of-line-graph