CSV read, edit specific field, write

[cswarwick]

I am attempting to read a CSV file, edit a specific entry, then write back to disk. I am having trouble writing back to disk. I used split to separate fields and change. I can print the changes, but now I cannot write them back to the file. Can someone show me a quick simple example? (for simplicity I am using a small data file with 10 entries, seperated with commas, no headers)

Thank you

[bvdet]

Let's say you read the csv file into a list of lists named dataList and you want to change the last element in the first line.

import csv

dataList = [0.0, 5.0, 10.0, 15.0, 20.0, 25.0, 30.0, 35.0, 40.0, 45.0, 50.0],\
           [0.0, 5.0, 10.0, 15.0, 20.0, 25.0, 30.0, 30.0, 30.0, 30.0, 30.0], \
           [0.0, 0.0, 0.0, 5.0, 10.0, 15.0, 20.0, 25.0, 30.0, 30.0, 30.0],\
           [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 5.0, 10.0, 15.0, 20.0, 25.0]

dataList[0][-1] = "XXXX"

fn = r'D:\tmp\some.csv'
f = open(fn, 'wb')
w = csv.writer(f)

w.writerows(dataList)
f.close()

[cswarwick]

Ok good. How would I allow user input to choose which entry?

[bvdet]

That depends on what you want. You could prompt the user using built-in function raw_input (input in Python 3.x) for the line and column to change and the new value, or you could build a GUI with Tkinter or other GUI toolkit with rows and columns of widgets where the user could edit whatever he wants.