Pandas: Groupby and aggregate over multiple lists
Pandas Grouping and Aggregating: Split-Apply-Combine Exercise-30 with Solution
Write a Pandas program to split the following dataset using group by on first column and aggregate over multiple lists on second column.
Test Data:
student_id marks 0 S001 [88, 89, 90] 1 S001 [78, 81, 60] 2 S002 [84, 83, 91] 3 S002 [84, 88, 91] 4 S003 [90, 89, 92] 5 S003 [88, 59, 90]
Sample Solution:
Python Code :
import pandas as pd
import numpy as np
pd.set_option('display.max_rows', None)
pd.set_option('display.max_columns', None)
df = pd.DataFrame({
'student_id': ['S001','S001','S002','S002','S003','S003'],
'marks': [[88,89,90],[78,81,60],[84,83,91],[84,88,91],[90,89,92],[88,59,90]]})
print("Original DataFrame:")
print(df)
print("\nGroupby and aggregate over multiple lists:")
result = df.set_index('student_id')['marks'].groupby('student_id').apply(list).apply(lambda x: np.mean(x,0))
print(result)
Sample Output:
Original DataFrame: student_id marks 0 S001 [88, 89, 90] 1 S001 [78, 81, 60] 2 S002 [84, 83, 91] 3 S002 [84, 88, 91] 4 S003 [90, 89, 92] 5 S003 [88, 59, 90] Groupby and aggregate over multiple lists: student_id S001 [83.0, 85.0, 75.0] S002 [84.0, 85.5, 91.0] S003 [89.0, 74.0, 91.0] Name: marks, dtype: object
Python Code Editor:
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Previous: Write a Pandas program to split a given dataset using group by on specified column into two labels and ranges.
Next: Write a Pandas program to split the following dataset using group by on ‘salesman_id’ and find the first order date for each group.
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Python: Tips of the Day
Python: Time library
Time library provides lots of time related functions and methods and is good to know whether you're developing a website or apps and games or working with data science or trading financial markets. Time is essential in most development pursuits and Python's standard time library comes very handy for that.
Let's check out a few simple examples:
moment=time.strftime("%Y-%b-%d__%H_%M_%S",time.localtime())
import time time_now=time.strftime("%H:%M:%S",time.localtime()) print(time_now) date_now=time.strftime("%Y-%b-%d",time.localtime()) print(date_now)
Output:
11:36:34 2020-Nov-30
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