Writing Python lists to columns in csv

Question

I have 5 lists, all of the same length, and I’d like to write them to 5 columns in a CSV. So far, I can only write one to a column with this code:

with open('test.csv', 'wb') as f:
    writer = csv.writer(f)
    for val in test_list:
        writer.writerow([val])

If I add another for loop, it just writes that list to the same column. Anyone know a good way to get five separate columns?

Asked By: Alex Chumbley

||

Source

Answer 1

Change them to rows:

rows = zip(list1, list2, list3, list4, list5)

Then just:

import csv

with open(newfilePath, "w") as f:
    writer = csv.writer(f)
    for row in rows:
        writer.writerow(row)

Answered By: Joran Beasley

Answer 2

You can use izip to combine your lists, and then iterate them

for val in itertools.izip(l1,l2,l3,l4,l5):
    writer.writerow(val)

Answered By: jh314

Answer 3

The following code writes python lists into columns in csv

import csv
from itertools import zip_longest
list1 = ['a', 'b', 'c', 'd', 'e']
list2 = ['f', 'g', 'i', 'j']
d = [list1, list2]
export_data = zip_longest(*d, fillvalue = '')
with open('numbers.csv', 'w', encoding="ISO-8859-1", newline='') as myfile:
      wr = csv.writer(myfile)
      wr.writerow(("List1", "List2"))
      wr.writerows(export_data)
myfile.close()

The output looks like this

Answered By: Ashok Kumar Jayaraman

Answer 4

import csv
dic = {firstcol,secondcol} #dictionary
csv = open('result.csv', "w") 
for key in dic.keys():
    row ="n"+ str(key) + "," + str(dic[key]) 
    csv.write(row)

Answered By: Shb8086

Answer 5

If you are happy to use a 3rd party library, you can do this with Pandas. The benefits include seamless access to specialized methods and row / column labeling:

import pandas as pd

list1 = [1, 2, 3]
list2 = [4, 5, 6]
list3 = [7, 8, 9]

df = pd.DataFrame(list(zip(*[list1, list2, list3]))).add_prefix('Col')

df.to_csv('file.csv', index=False)

print(df)

   Col0  Col1  Col2
0     1     4     7
1     2     5     8
2     3     6     9

Answered By: jpp

Answer 6

I didn’t want to import anything other than csv, and all my lists have the same number of items. The top answer here seems to make the lists into one row each, instead of one column each. Thus I took the answers here and came up with this:

import csv
list1 = ['a', 'b', 'c', 'd', 'e']
list2 = ['f', 'g', 'i', 'j','k']
with open('C:/test/numbers.csv', 'wb+') as myfile:
    wr = csv.writer(myfile)
    wr.writerow(("list1", "list2"))
    rcount = 0
    for row in list1:
        wr.writerow((list1[rcount], list2[rcount]))
        rcount = rcount + 1
    myfile.close()

Answered By: Bartats

Answer 7

I just wanted to add to this one- because quite frankly, I banged my head against it for a while – and while very new to python – perhaps it will help someone else out.

 writer.writerow(("ColName1", "ColName2", "ColName"))
                 for i in range(len(first_col_list)):
                     writer.writerow((first_col_list[i], second_col_list[i], third_col_list[i]))

Answered By: BinaryPhinary

Writing Python lists to columns in csv

Question:

Answers: