How to create a function that converts month values into quarter using if statement in python-CodePudding

I need to create a function called as convert_to_qtr() that converts monthly values in the month value of data frame into quarters. Given below is the month data frame below:-

In the convert_to_qtr() function, we should use the following if conditions:- • If the month input is Jan-Mar, then the function returns “Q1” • If the month input is Apr-Jun, then the function returns “Q2” • If the month input is Jul-Sep, then the function returns “Q3” • If the month input is Oct-Dec, then the function returns “Q4”

Then this function should be applied to Month Dataframe provided above and a new column called as Quarter should be created that contains the quarter of each observations of months(January, Feb) etc it is aligned to .

quarter = 0
excl_merged['quarter'] = excl_merged[quarter] 

excl_merged
def convert_to_quarterly(excl_merged):
    if excl_merged['Month'] == 'January' &  excl_merged['Month'] == 'February' &  excl_merged['Month'] == 'March':
        print(excl_merged[quarter] == 'Q1')
    elif excl_merged['Month'] == 'April' &  excl_merged['Month'] == 'May' &  excl_merged['Month'] == 'June':
        print(excl_merged[quarter] == 'Q2')
    elif excl_merged['Month'] == 'July' &  excl_merged['Month'] == 'August' &  excl_merged['Month'] == 'September':
        print(excl_merged[quarter] == 'Q3')
    else:
        print(excl_merged[quarter] == 'Q4')
        

convert_to_quarterly(excl_merged)

I was not able to run the function properly and hence was getting errors

CodePudding user response：

Try the following:

def convert_to_quarterly(excl_merged):
    if excl_merged['Month'] in ['January', 'February', "March"]:
        excl_merged[quarter] == 'Q1'
    elif excl_merged['Month'] in ["April", "May", "June"]:
        excl_merged[quarter] == 'Q2'
    elif excl_merged['Month'] in ['July', 'August', 'September']:
        excl_merged[quarter] == 'Q3'
    elif excl_merged["Month"] in ["November", "December", "December"]:
        excl_merged[quarter] == 'Q4'
    else:
        print("Unkown month name!")

The main problem is that you are using an and statement. A month can't be "Januar" and "Fabruary".

I would also recoment to use brackets when useing the & or | operator around the single bool operations.

At last i would recoment to use the in operator to test against all three values at one. It should be faster and the code is much easier to read.

CodePudding user response：

Wouldn't it be easier to do something like:

df.Transaction_Timestamp.apply(lambda x: "Q"   str(x.quarter))

Example

import pandas as pd
import numpy as np

rng = np.random.default_rng()
df = pd.DataFrame({
    "Transaction_Timestamp":pd.date_range("2022-01-01", periods=365),
    "Value":rng.integers(0, 100, size=365)
})

df["Qrt"] = df.Transaction_Timestamp.apply(lambda x: "Q"   str(x.quarter))

df.head()

    Transaction_Timestamp   Value   Qrt
0   2022-01-01              84      Q1
1   2022-01-02              43      Q1
2   2022-01-03              91      Q1
3   2022-01-04              29      Q1
4   2022-01-05              88      Q1