Prerequisites:
In this article, we will learn how to plot multiple columns on bar chart using Matplotlib. Bar Plot is used to represent categories of data using rectangular bars. We can plot these bars with overlapping edges or on same axes. Different ways of plotting bar graph in the same chart are using matplotlib and pandas are discussed below.
Method 1: Providing multiple columns in y parameter
The trick here is to pass all the data that has to be plotted together as a value to ‘y’ parameter of plot function.
Syntax:
matplotlib.pyplot.plot(\*args, scalex=True, scaley=True, data=None, \*\*kwargs)
Approach:
- Import module
- Create or load data
- Pass data to plot()
- Plot graph
Example:
Python3
# importing pandas libraryimport pandas as pd# import matplotlib libraryimport matplotlib.pyplot as plt # creating dataframedf = pd.DataFrame({ 'Name': ['John', 'Sammy', 'Joe'], 'Age': [45, 38, 90], 'Height(in cm)': [150, 180, 160]}) # plotting graphdf.plot(x="Name", y=["Age", "Height(in cm)"], kind="bar") |
Output:
Method 2: By plotting on the same axis
Plotting all separate graph on the same axes, differentiated by color can be one alternative. Here again plot() function is employed.
Approach:
- Import module
- Create or load data
- Plot first graph
- Plot all other graphs on the same axes
Example:
Python3
# importing pandas libraryimport pandas as pd# import matplotlib libraryimport matplotlib.pyplot as plt # creating dataframedf = pd.DataFrame({ 'Name': ['John', 'Sammy', 'Joe'], 'Age': [45, 38, 90], 'Height(in cm)': [150, 180, 160]}) # plotting Heightax = df.plot(x="Name", y="Height(in cm)", kind="bar")# plotting age on the same axisdf.plot(x="Name", y="Age", kind="bar", ax=ax, color="maroon") |
Output:
Method 3: By creating subplots
Another way of creating such a functionality can be plotting multiple subplots and displaying them as one. This can be done using subplot() function.
Syntax:
subplot(nrows, ncols, index, **kwargs)
Approach:
- Import module
- Create or load data
- Create multiple subplots
- Plot on single axes
Example:
Python3
# importing pandas libraryimport pandas as pd# import matplotlib libraryimport matplotlib.pyplot as plt # creating dataframedf = pd.DataFrame({ 'Name': ['John', 'Sammy', 'Joe'], 'Age': [45, 38, 90], 'Height(in cm)': [150, 180, 160]}) # creating subplots and plotting them togetherax = plt.subplot()ax.bar(df["Name"], df["Height(in cm)"])ax.bar(df["Name"], df["Age"], color="maroon") |
Output:
