How do I create a pie chart using categorical data in matplotlib?

Question

I have data as follows:

ID  Gender  Country  ...
1   Male    UK
2   Female  US
3   Male    NZ
4   Female  UK
...

There are only 2 options for gender and 3 for country. I would like to create a seperate pie chart for both "Gender" and "Country" to show how many times each option shows up in the data but I'm quite confused about how to do so.

The data is stored in a pandas dataframe.

Any and all help is much appreciated!

Solution 1

Here is an approach using pandas:

import pandas as pd
import numpy as np
from matplotlib import pyplot as plt

def label_function(val):
    return f'{val / 100 * len(df):.0f}\n{val:.0f}%'

N = 50
df = pd.DataFrame({'country': np.random.choice(['UK', 'US', 'NZ'], N),
                   'gender': np.random.choice(['Male', 'Female'], N)})

fig, (ax1, ax2) = plt.subplots(ncols=2, figsize=(10, 5))

df.groupby('country').size().plot(kind='pie', autopct=label_function, textprops={'fontsize': 20},
                                  colors=['tomato', 'gold', 'skyblue'], ax=ax1)
df.groupby('gender').size().plot(kind='pie', autopct=label_function, textprops={'fontsize': 20},
                                 colors=['violet', 'lime'], ax=ax2)
ax1.set_ylabel('Per country', size=22)
ax2.set_ylabel('Per gender', size=22)plt.tight_layout()
plt.show()

PS: To just show the percentage, use autopct='%1.0f%%'.

Solution 2

I assume you started with this

import pandas as pd
from matplotlib.pyplot import pie, axis, show

df = pd.DataFrame([[1,'Male','UK'],   [2, 'Female', 'NZ'],    [3, 'Male', 'UK'], [4, 'Male', 'US']], columns=['ID',  'Gender',  'Country'])

Plot for gender

df.groupby('gender').size().plot(kind='pie', autopct='%.2f')

Plot for country

df.groupby('country').size().plot(kind='pie', autopct='%.2f')

Solution 3

Okay so since you are using a dataframe like this:

data = pd.DataFrame([[1,'Male','UK'],   [2, 'Female', 'NZ'],    [3, 'Male', 'UK'], [4, 'Male', 'US']], columns=['ID',  'Gender',  'Country'])

You can really just do:

data['Gender'].value_counts().plot(kind='pie')

If you wanna do it manually:

people = len(data.Gender)
genders = len(set(data.Gender))

res = []
for gender in set(data.Gender):
    res.append([gender, len(data[data['Gender']==gender]), len(data[data['Gender']==gender])/people])

and then just plot it.

Comments

[Nils]

In what kind of data structure is your data?

[Manesh Halai]

It is stored in a pandas dataframe

[Manesh Halai]

This is great thanks! Is there anyway to also add data labels to the chart so that they show the amount/percentage on the chart as well?

[Manesh Halai]

This is great thanks! Is there anyway to also add data labels to the chart so that they show the amount/percentage on the chart as well?