MERGING AND SPLITTING COLUMNS IN PANDAS

Listing B.20 shows the contents of employees.csv and Listing B.21 shows the contents of emp_merge_split.py; these examples illustrate how to merge columns and split columns of a CSV file.

Listing B.20: employees.csv

name,year,month
Jane-Smith,2015,Aug
Dave-Smith,2020,Jan
Jane-Jones,2018,Dec
Jane-Stone,2017,Feb
Dave-Stone,2014,Apr
Mark-Aster,,Oct
Jane-Jones,NaN,Jun

Listing B.21: emp_merge_split.py

import pandas as pd

emps = pd.read_csv("employees.csv")
print("emps:")
print(emps)
print()

emps['year']  = emps['year'].astype(str)
emps['month'] = emps['month'].astype(str)

# separate column for first name and for last name:
emps['fname'],emps['lname'] = emps['name'].str.
split("-",1).str

# concatenate year and month with a "#" symbol:
emps['hdate1'] = emps['year'].
astype(str)+"#"+emps['month'].astype...