How to write data into separate cells in CSV via Python

Question

I am trying to add a few new columns with fixed values to the csv using python but the all the values are squeezed into one cell instead of separate cells. How to fix this?

My python code:

default_text = 'AoE'

with open('C:/Users/username/Desktop/Output/AoE_test.csv', 'r', newline='') as read_obj, \
        open('C:/Users/username/Desktop/Output/output_1.csv', 'w', newline='') as write_obj:
    csv_reader = reader(read_obj, delimiter=',')
    csv_writer = writer(write_obj, delimiter=',')
    for row in csv_reader:
        row.append(default_text)
        csv_writer.writerow(row)

This is the orginal CSV (AoE_test.csv) which the code reads data from:

This is the final output of the csv (output_1.csv) written with the data:

I've also tried to comment out the row.append():

    for row in csv_reader:
        # row.append(default_text)
        csv_writer.writerow((row, default_text))

and the output:

I want the addtional column to be written in a separate column in CSV file. Thanks so much in advance!

Looks to me like you are creating a new row instead of adding data to the end of the row. Also I could be wrong, but it looks like your data is encapsulated within brackets so it may be being read/written incorrectly. You can manually add ", " and the column data at the end of the line by parsing through the csv file and using a file handler to write the output to a new file. — Jamin
– Jamin, Commented Feb 26, 2020 at 23:47
default_text = 'AoE' with open('C:/Users/username/Desktop/Output/AoE_test.csv', 'r', newline='') as read_obj, \ open('C:/Users/username/Desktop/Output/output_1.csv', 'w', newline='') as write_obj: csv_reader = reader(read_obj, delimiter=',') csv_writer = writer(write_obj, delimiter=',') for row in csv_reader: row.append(default_text) csv_writer.writerow(row) — an1que
– an1que, Commented Feb 26, 2020 at 23:57
@an1que In your post, not as a comment, that's unreadable. We would still be missing the data, too. Speaking of, please do not share information as images unless absolutely necessary. See: meta.stackoverflow.com/questions/303812/…, idownvotedbecau.se/imageofcode, idownvotedbecau.se/imageofanexception. — AMC
– AMC, Commented Feb 27, 2020 at 0:22

Gwang-Jin Kim · Accepted Answer · 2020-02-27 13:10:16Z

1

Use pandas when dealing with tables. What you want to do is exactly this:

# pip install pandas
import pandas as pd

default_text = 'AoE'

in_fpath = 'C:/Users/username/Desktop/Output/AoE_test.csv'
out_fpath = 'C:/Users/username/Desktop/Output/output_1.csv', 'w'
df = pd.read_csv(in_fpath, sep=",") # while sep="," is default
df['my_new_col'] = default_text # this works, because 
# pandas takes this one string and repeats it in column
# actually you should put [default_text] * df.shape[0]
# think columns as vertical lists!
df.to_csv(out_fpath)

edited Feb 27, 2020 at 13:10

answered Feb 27, 2020 at 6:23

Gwang-Jin Kim

11.1k20 silver badges39 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to write data into separate cells in CSV via Python

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related