Python: Write list of lists to CSV

Question

In my python script I'm having a list that has the following structure:

['00:00', 'abc', '2', 'xyz']
['00:01', 'cde', '3', 'sda']

and so on. I want to write this list to csv file in a way that every element is in separate row and every string in one element is in separate column. So I want to end up with the following result in csv file:

     A     |     B    |     C    |     D
1  00:00   |    abc   |     2    |    xyz     
2  00:01   |    xyz   |     3    |    sda

Currently I have a code like this:

with open('test1.csv',mode='w',encoding='UTF-8') as result_file:
    wr = csv.writer(result_file, dialect='excel')
    for x in data:
        wr.writerow(x)

and the result I get is that every element of the list is written to column A, so it looks like this:

             A               |       
1  '00:00','abc','2','xyz'   |

How can I achieve splitting each string to separate column in csv file?

--edit

If I run the code from the first three answers I get the same result(except for the delimeter):

But my idea it to get 00:00 in column A, -6 in column B and so on..

Those are two lists. Can you confirm if its a list of lists or a dict of lists maybe? — amanb
– amanb, Commented Mar 10, 2020 at 20:46
Actually it's a 2 dimensional array/list. The whole structure is called data and I can get the value for each string by typing data[i][j] — izotop
– izotop, Commented Mar 10, 2020 at 20:51
Sorry, the it's the list of lists, so it has a structure: [['00:00', 'abc', '2', 'xyz'] ['00:01', 'cde', '3', 'sda'] ] — izotop
– izotop, Commented Mar 10, 2020 at 21:01

narendra-choudhary · Accepted Answer · 2020-03-10 21:23:40Z

1

How each list appears in CSV file depends on what data structure data is.

For data to be a list of lists, following code should work fine.

import csv

data = []
d1 = ['00:00', 'abc', '2', 'xyz']
d2 = ['00:01', 'cde', '3', 'sda']

data.append(d1)
data.append(d2)

with open('results_file.csv', mode='w') as results_file:
    results_writer = csv.writer(results_file, delimiter='|', quotechar='"', 
        quoting=csv.QUOTE_MINIMAL)
    results_writer.writerow(['A','B','C','D'])
    for x in data:
        results_writer.writerow(x)

results_file.csv looks like:

A|B|C|D
00:00|abc|2|xyz
00:01|cde|3|sda

answered Mar 10, 2020 at 21:23

narendra-choudhary

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2 Comments

izotop Over a year ago

Ok, but how can I do it if my data list has a lot of elements not only 2?

narendra-choudhary Over a year ago

The code in answer should work for any number of list elements in data, not just for 2. I had added 2 lists in data just for an example.

s3dev · Accepted Answer · 2020-03-10 22:41:14Z

0

How about a pandas approach? Nice and simple ...

import pandas as pd

data = [['00:00', 'abc', '2', 'xyz'], ['00:01', 'cde', '3', 'sda']] 
cols = ['A', 'B', 'C', 'D']

# Load data into a DataFrame.
df = pd.DataFrame(data, columns=cols)
# Write the CSV.
df.to_csv('output.csv', sep='|', index=False)

Per the docs you can change the separator using the sep parameter.

[Edited] Output:

Content of output.csv as shown from the console:

user@host ~/Desktop/so
$ cat output.csv
A|B|C|D
00:00|abc|2|xyz
00:01|cde|3|sda

edited Mar 10, 2020 at 22:41

answered Mar 10, 2020 at 21:24

s3dev

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3 Comments

izotop Over a year ago

Unfortunetly it doesnt work.. Still all of the strings are written to one column

s3dev Over a year ago

Just opened the CSV in Libre Calc and each value is in its own column as expected. I'll revise the output because it is misleading.

s3dev Over a year ago

@izotop - I've updated to use a pipe delimiter | for you. Just pass whatever you like into the sep parameter.

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