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+--- Thread: how to add a new column to dataframe using pandas (/thread-38332.html)
how to add a new column to dataframe using pandas - truffleoil - Sep-29-2022
My script below is returning the error 'NoneType' and i can't figure out why.
import pandas as pd
from os import listdir
from os.path import isfile, join
onlyfiles = [f for f in listdir('.') if isfile(join('.', f))]
print(onlyfiles)
#add new column
for file in onlyfiles:
if file[:1] != '.' and file[-5:] != 'ipynb':
print(file)
bls_data = pd.read_csv(file)
df['study_id'] = df['project_id'].astype(str) + '_1'
df = df.to_csv('07newcolumn/' + file[:-5] + 'vF.csv', index=True)Im essentially looking to create a new column called "study_id" that takes an existing column (project_id) and adds "_1" at the end of each row value. So for example right beside project_id, the script would create a new new column called study_id that adds "_1" at the end of each row value.project_id
abcd
jklm
NEW COLUMN
study_id
abcd_1
jklm_1
Any help is appreciated thank you!