Saving lists in python as semicolon delimited text file

Question

I have three lists in Python. I want to save these lists as a semicolon delimited text file (with a heading).

For example, lets consider these three lists:

l1 = ['a1', 'a2', 'a3', 'a4', 'a5']
l2 = [1,2,3,4,5]
l3 = [20.0, 25.1, 51.2, 60.2, 75.0]

and header, ['Label1', 'Label2', 'Label3']

I want these lists to be saved as columns in a text file in the following form:

Label1; Label2; Label3
a1;1;20.0%
a2;2;25.1%
a3;3;51.2%
a4;4;60.2%
a5;5;75.0%

In addition to saving the file in the above format, I want to have percentage symbols while writing the last column. I checked this post, but I am still confused about how I can implement this. I am using python 2.7.

I will really appreciate any help.

timgeb: Thanks for your suggestion. I would have liked to follow your suggestion. But, I need to adhere to a laid standard here. — Ross, Oct 30 '18 at 06:27

user2390182 · Accepted Answer · 2018-10-30T06:38:07.310

5

The following will work, using the csv module and zip:

l1 = ['a1', 'a2', 'a3', 'a4', 'a5']
l2 = [1,2,3,4,5]
l3 = [20.0, 25.1, 51.2, 60.2, 75.0]
header = ['Label1', 'Label2', 'Label3'] 

import csv

with open('output.csv', 'w') as f:
    w = csv.writer(f, delimiter=';')
    w.writerow(header)
    for row in zip(l1, l2, (str(x)+'%' for x in l3)):
        w.writerow(row)

edited Oct 30 '18 at 06:38

answered Oct 30 '18 at 06:35

user2390182

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Alfred Ayi-bonte · Answer 2 · 2018-10-30T06:47:52.823

2

l1 = ['a1', 'a2', 'a3', 'a4', 'a5']
l2 = [1,2,3,4,5]
l3 = [20.0, 25.1, 51.2, 60.2, 75.0]
answer = ''
for i in range(len(l1)):
    value = "{0};{1};{2}%".format(l1[i], l2[i], l3[i])
    answer = answer+"\n"+value

header = ['Label1', 'Label2', 'Label3'] 
title = ';'.join(header)
answer = title + answer
print(answer)

file = open("answer.txt","w") 
file.write(answer)
file.close()

edited Oct 30 '18 at 06:47

answered Oct 30 '18 at 06:31

Alfred Ayi-bonte

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in place of the print write to the file – Alfred Ayi-bonte Oct 30 '18 at 06:34
Alfred Ayi-bonte: Thanks for your answer. How can I save this string 'answer' as a text file? Also, I would like to keep the header as the first row in my text file. How can I do this? – Ross Oct 30 '18 at 06:35
1

@Ross use ``` file = open("answer.txt","w") file.write(answer) file.close()``` to write your answer – Alfred Ayi-bonte Oct 30 '18 at 06:48

timgeb · Answer 3 · 2018-10-30T06:40:28.967

1

You can transpose your rows using zip and then process them with the csv module.

>>> import csv
>>> l1 = ['a1', 'a2', 'a3', 'a4', 'a5']
>>> l2 = [1,2,3,4,5]
>>> l3 = [20.0, 25.1, 51.2, 60.2, 75.0]
>>> l3_percent = ['{!r}%'.format(x) for x in l3]
>>> header = ['Label1', 'Label2', 'Label3']
>>> rows = zip(l1, l2, l3_percent)
>>>
>>> with open('out.csv', 'w') as f:
...:    writer = csv.writer(f, delimiter=';', quoting=csv.QUOTE_NONE)
...:    writer.writerow(header)
...:    writer.writerows(rows)

This produces

Label1;Label2;Label3
a1;1;20.0%
a2;2;25.1%
a3;3;51.2%
a4;4;60.2%
a5;5;75.0%

edited Oct 30 '18 at 06:40

answered Oct 30 '18 at 06:37

timgeb

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timgeb: Thanks very much. Your suggestion works perfectly well. :-) – Ross Oct 30 '18 at 06:39

Saving lists in python as semicolon delimited text file

3 Answers3