Writing python list as CSV

Question

Just having a bit of a struggle getting the right formatting with the csv output files.

I have the following list called found in python:

   [['dropbearid', 'distance'],
    ['DB_1487', 17.543651156695343],
    ['DB_1901', 24.735333924441772],
    ['DB_2800', 6.607094868078008]]

When I use

import csv
out = csv.writer(open("myfile.csv","w"), delimiter=',',quoting=csv.QUOTE_ALL)
out.writerow(found)

I get a file that when I open in excel has the values but it has 'dropbearid','distance' in one cell and 'DB_1487','17.54...' in the next cell and so on all continued across the first row.

Is there a way to get the output setup so 'dropbearid' and 'distance' are placed across two columns and all the list below are put in rows below?

Thanks!

For inserting each row you need to call `out.writerow` seperately, or you may use `out.writerows()` — ZdaR, Aug 31 '18 at 05:05
Pretty easy way to do that using numpy here https://stackoverflow.com/questions/6081008/dump-a-numpy-array-into-a-csv-file — A. J. Alger, Aug 31 '18 at 05:06

Bernhard · Answer 1 · 2018-08-31T06:34:59.683

4

Welcome to Stackoverflow. You write the list of lists to one row, which is why you have two values in one cell, because you write every element of found (which is a list of two elements) in a cell. You need to iterate over the list of lists and write every list to a row. This should work:

import csv
out = csv.writer(open("myfile.csv","w"), delimiter=',',quoting=csv.QUOTE_ALL, newline='')
for row in found:
    out.writerow(row)

edited Aug 31 '18 at 06:34

answered Aug 31 '18 at 05:05

Bernhard

1,227
8
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1

Add newline='' in writerobj else you will end up in having blank lines in your file. – SanthoshSolomon Aug 31 '18 at 05:13

score 1 · Answer 2 · answered Aug 31 '18 at 05:12

The function writerow() will write a single row. So you need to use writerows() and set newline parameter as '' to avoid blank rows in file.

found = [['dropbearid', 'distance'],
    ['DB_1487', 17.543651156695343],
    ['DB_1901', 24.735333924441772],
    ['DB_2800', 6.607094868078008]]
import csv
with open('myfile.csv', 'w', newline='') as outfile:
    writer = csv.writer(outfile)
    writer.writerows(found)

Hope this helps! Cheers!

score 1 · Answer 3 · answered Aug 31 '18 at 06:01

import pandas as pd
found = [['dropbearid', 'distance'],['DB_1487', 17.543651156695343],['DB_1901', 24.735333924441772],['DB_2800', 6.607094868078008]]
dffound = pd.DataFrame(found)
header = dffound.iloc[0]
dffound = dffound[1:]
dffound.rename(columns = header)
dffound.tocsv("enter path here")

score 0 · Answer 4 · answered Aug 31 '18 at 05:39

0

Use pandas DataFrames for writing lists to CSV's, it makes formatting lot easier

import pandas as pd
dffound = pd.DataFrame(found,columns=['dropbearid', 'distance'])
dffound.to_csv('Found.csv')

answered Aug 31 '18 at 05:39

Soubhik Banerjee

342
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6
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score 0 · Answer 5 · answered Aug 31 '18 at 06:24

0

You would use the writerows function instead of writerow, to write each item of the sub-list as a column.

with open('myfile.csv', 'w+') as csv_file:
    writer = csv.writer(csv_file, delimiter=',')
    writer.writerows(d)

answered Aug 31 '18 at 06:24

Akay Nirala

1,086
7
12

score 0 · Answer 6 · answered Aug 31 '18 at 06:42

0

Use pandas library for this.

import pandas as pd
df = pd.DataFrame(found, columns=['dropbearid', 'distance'])
df = df.drop(0) # drop the header row
df.to_csv('Found.csv', index=False)

answered Aug 31 '18 at 06:42

Paresh

616
5
7

Writing python list as CSV

6 Answers6