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Python - How to Group Pandas DataFrame by Year?
We will group Pandas DataFrame using the groupby(). Select the column to be used using the grouper function. We will group year-wise and calculate sum of Registration Price with year interval for our example shown below for Car Sale Records.
At first, let’s say the following is our Pandas DataFrame with three columns −
# dataframe with one of the columns as Date_of_Purchase
dataFrame = pd.DataFrame(
{
"Car": ["Audi", "Lexus", "Tesla", "Mercedes", "BMW", "Toyota", "Nissan", "Bentley", "Mustang"],
"Date_of_Purchase": [pd.Timestamp("2021-06-10"),
pd.Timestamp("2019-07-11"),
pd.Timestamp("2016-06-25"),
pd.Timestamp("2021-06-29"),
pd.Timestamp("2020-03-20"),
pd.Timestamp("2019-01-22"),
pd.Timestamp("2011-01-06"),
pd.Timestamp("2013-01-04"),
pd.Timestamp("2014-05-09")
],
"Reg_Price": [1000, 1400, 1100, 900, 1700, 1800, 1300, 1150, 1350]
}
)Next, use the Grouper to select Date_of_Purchase column within groupby function. The frequency is set as 3Y i.e. interval of 3 Years grouped.
Example
Following is the code −
import pandas as pd
# dataframe with one of the columns as Date_of_Purchase
dataFrame = pd.DataFrame(
{
"Car": ["Audi", "Lexus", "Tesla", "Mercedes", "BMW", "Toyota", "Nissan", "Bentley", "Mustang"],
"Date_of_Purchase": [pd.Timestamp("2021-06-10"),
pd.Timestamp("2019-07-11"),
pd.Timestamp("2016-06-25"),
pd.Timestamp("2021-06-29"),
pd.Timestamp("2020-03-20"),
pd.Timestamp("2019-01-22"),
pd.Timestamp("2011-01-06"),
pd.Timestamp("2013-01-04"),
pd.Timestamp("2014-05-09")
],
"Reg_Price": [1000, 1400, 1100, 900, 1700, 1800, 1300, 1150, 1350]
}
)
print("DataFrame...\n",dataFrame)
# Grouper to select Date_of_Purchase column within groupby function
print("\nGroup Dataframe by 3 years...\n",dataFrame.groupby(pd.Grouper(key='Date_of_Purchase', axis=0, freq='3Y')).sum())Output
This will produce the following output −
DataFrame... Car Date_of_Purchase Reg_Price 0 Audi 2021-06-10 1000 1 Lexus 2019-07-11 1400 2 Tesla 2016-06-25 1100 3 Mercedes 2021-06-29 900 4 BMW 2020-03-20 1700 5 Toyota 2019-01-22 1800 6 Nissan 2011-01-06 1300 7 Bentley 2013-01-04 1150 8 Mustang 2014-05-09 1350 Group Dataframe by 3 years... Reg_Price Date_of_Purchase 2011-12-31 1300 2014-12-31 2500 2017-12-31 1100 2020-12-31 4900 2023-12-31 1900
Updated on: 30-Sep-2021
1K+ Views
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