Question

I have a python script that generates a bunch of data in a while loop. I need to write this data to a CSV file, so it writes by column rather than row.

For example in loop 1 of my script I generate:

(1, 2, 3, 4)

I need this to reflect in my csv script like so:

Result_1    1
Result_2    2
Result_3    3
Result_4    4

On my second loop i generate:

(5, 6, 7, 8)

I need this to look in my csv file like so:

Result_1    1    5
Result_2    2    6
Result_3    3    7
Result_4    4    8

and so forth until the while loop finishes. Can anybody help me?

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EDIT

The while loop can last over 100,000 loops

Answer 1

The reason csv doesn’t support that is because variable-length lines are not really supported on most filesystems. What you should do instead is collect all the data in lists, then call zip() on them to transpose them after.

>>> l = [('Result_1', 'Result_2', 'Result_3', 'Result_4'), (1, 2, 3, 4), (5, 6, 7, 8)]
>>> zip(*l)
[('Result_1', 1, 5), ('Result_2', 2, 6), ('Result_3', 3, 7), ('Result_4', 4, 8)]