Pandas: Count city wise number of people from a given of data set (city, name of the person)
Write a Pandas program to count city wise number of people from a given of data set (city, name of the person).
Sample data:
city Number of people
0 California 4
1 Georgia 2
2 Los Angeles 4
Sample Solution :
Python Code :
import pandas as pd
df1 = pd.DataFrame({'name': ['Anastasia', 'Dima', 'Katherine', 'James', 'Emily', 'Michael', 'Matthew', 'Laura', 'Kevin', 'Jonas'],
'city': ['California', 'Los Angeles', 'California', 'California', 'California', 'Los Angeles', 'Los Angeles', 'Georgia', 'Georgia', 'Los Angeles']})
g1 = df1.groupby(["city"]).size().reset_index(name='Number of people')
print(g1)
Sample Output:
city Number of people 0 California 4 1 Georgia 2 2 Los Angeles 4
Explanation:
In the above code -
- Creates a Pandas DataFrame called df1 with two columns, "name" and "city", and 10 rows of data.
- Groups the rows of df1 by the "city" column using the groupby() method.
- Applies the size() method to each group to count the number of rows in each group.
- Resets the index of the resulting DataFrame using the reset_index() method and renames the column with the count as "Number of people".
- Stores the resulting DataFrame in a variable called g1.
- The resulting DataFrame has two columns: "city" and "Number of people".
- Prints the contents of g1 to the console.
Python-Pandas Code Editor:
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