How to write a while loop into a CSV file

Question

My code looks like:

x=0
while (x<3):
    print('purple'),
    print('yellow'),
    print({x})
    x=x+1

I want it to log this data into a csv file named 'daffodils.csv'. How do I do this so that the iterations won't write over eachother?

For example, if I ran the program two times, my csv file will look like:

purple yellow 0
purple yellow 1
purple yellow 2
purple yellow 0
purple yellow 1
purple yellow 2

Thanks

FYI: That is not a valid csv file (unless it's a single column). — TemporalWolf, Feb 14 '17 at 21:51
`print({x})` creates and prints a *set* containing `x`, is that really what you want? — jonrsharpe, Feb 14 '17 at 21:57
It sounds like the words in the question are asking [How do you append to a file?](http://stackoverflow.com/questions/4706499/how-do-you-append-to-a-file) but the code blocks don't seem to have any relation to file io... — Tadhg McDonald-Jensen, Feb 14 '17 at 22:55

SparkAndShine · Answer 1 · 2017-02-14T22:16:56.500

1

Simply use,

with open('test.txt', 'a') as f:
    for x in range(3):
        s = 'purple yellow {}\n'.format(x)
        f.write(s)

Or use csv as you want,

import csv

with open('test.csv', 'a') as f:
    writer = csv.writer(f, delimiter=' ')
    for x in range(3):
        writer.writerow(['purple', 'yellow', x])

edited Feb 14 '17 at 22:16

answered Feb 14 '17 at 21:47

SparkAndShine

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`for x in range(3):` removes the need to set the default, while and increment. – TemporalWolf Feb 14 '17 at 21:49
1

@TemporalWolf, thx. just edited. – SparkAndShine Feb 14 '17 at 21:51

clubby789 · Accepted Answer · 2017-02-14T21:45:46.200

-1

Simply use:

t = open("daffodils.csv", "a+")
x=0
while (x<3):
    t.write('purple'),
    t.write('yellow'),
    t.write({x})
    t.write("\n")
    x=x+1
t.close()

The a opens the file in append mode, and the + creates it if it doesn't already exist.

edited Feb 14 '17 at 21:45

answered Feb 14 '17 at 21:41

clubby789

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4
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2

`.append`? That will be an `AttributeError` – juanpa.arrivillaga Feb 14 '17 at 21:44
Jammy, you might want to test that program before posting. – Robᵩ Feb 14 '17 at 21:44
Oh sorry, wasn't concentrating, let me just edit it – clubby789 Feb 14 '17 at 21:45

How to write a while loop into a CSV file

2 Answers2