update csv column value

Question

I have a CSV file named samplecsv that has 4 fields A,B,C,D as follows:

[a1,b1,c1,2]

[a2,b2,c2,2]

[a3,b3,c3,2]

I need to update field D from '2' to '9' for all row.How can I do it. I try the code as follows,but did not work.

import csv
f = open('C:/samplecsv.csv', 'w')
writer.writerow({'D':'9'})
f.close()

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score 0 · Accepted Answer · answered Dec 26 '17 at 10:37

0

you can use pandas instead of csv

import pandas as pd
df = pd.read_csv("C:/samplecsv.csv")
df["D"].replace(2,9, inplace=True)
df.to_csv("C:/samplecsv.csv",index=False)

answered Dec 26 '17 at 10:37

Emmet B

When I write back to CSV file ,It will add a column having sequence value 0,1,2,3,4.... ;So the CSV file will be [0,a1,b1,c1,9],[1,a2,b2,c2,9],[2,a3,b3,c3,9]. How can I avoid the sequence value when writing to CSV file? 3Q~ – PHE Dec 30 '17 at 03:36
I got the answer from another question on Stack Overflow .https://stackoverflow.com/questions/16923281/pandas-writing-dataframe-to-csv-file – PHE Dec 30 '17 at 04:50

1 Answers1