Python: Exporting a list of lists to .CSV

Question

With the structure:

mylist = [ [a,b,c,d], [e,f,g,h], .......[w,x,y,z]]

How can I export to a .csv file using each column and row like? Is there useful functions to quickly format lists to .csv files this way? I want each value in list to be a new tab in excel.

a   b   c   d
e   f   g   h
............
w   x   y   z

Possible duplicate of [Writing to CSV with Python adds blank lines](http://stackoverflow.com/questions/14693646/writing-to-csv-with-python-adds-blank-lines) — ZdaR, Mar 01 '17 at 14:50
Look at the builtin-in csv module's docs. And csv files don't have tabs. — RemcoGerlich, Mar 01 '17 at 14:52
They can have tabs. c in `csv` doesn't always mean comma. It sometimes means "character" — Eric Duminil, Mar 01 '17 at 14:52
The [documentation](https://docs.python.org/3/library/csv.html#csv.writer) explains writing CSV, and gives you an example in code. — dsh, Mar 01 '17 at 14:53

score 1 · Answer 1 · answered Mar 01 '17 at 14:53

1

You could use :

sep = "\t"

mylist = [['a', 'b', 'c'], ['d', 'e', 'f']]

with open('my.csv', 'w') as csv:
    for row in mylist:
        csv.write(sep.join(row))
        csv.write("\n")

Or the official csv lib.

my.csv is now :

a   b   c
d   e   f

answered Mar 01 '17 at 14:53

Eric Duminil

52,989
9
71
124

score 1 · Answer 2 · answered Mar 01 '17 at 14:53

I think this should do what you want.

csv_lines = []
for line in mylist:
    csv_lines.append(",".join(line))

f = open("mylist.csv", "w")
f.write("\n".join(csv_lines))
f.close()

The file mylist.csv should then be read correctly by excel automatically.

score 1 · Answer 3 · answered Mar 01 '17 at 15:01

1

This is an efficient way of doing it if you list is not VERY huge

with open('filename.csv', 'w') as file_handle:
    file_handle.write(map(lambda x:x.join(", "), mylist).join("\n"))

answered Mar 01 '17 at 15:01

Ajay Brahmakshatriya

8,993
3
26
49

Python: Exporting a list of lists to .CSV

3 Answers3