CODEWITHSUNDEEP
pythonlist
trenta coollime
trenta coollime

Reputation: 87

writing list of list into a COLUMNED .txt file via python

I have a list that looks like

[["a","b","c","d"],["e","f","g","h"],["i","j","k","l"]]

How can I convert this list of list into a text file that looks like

a  b  c  d
e  f  g  h
i  j  k  l

It seemed straightforward but none of the solution on the web seemed concise and elucidating enough for dummies like me to understand.

Thank you!

Upvotes: 5

Views: 301

Answers (6)

Jan
Jan

Reputation: 43169

Praise the power of comprehensions here:

lst = [["a","b","c","d"],["e","f","g","h"],["i","j","k","l"]]

out = "\n".join([" ".join(sublist) for sublist in lst])
print(out)

This yields

a b c d
e f g h
i j k l

Or, longer, maybe more understandable:

for sublist in lst:
    line = " ".join(sublist)
    print(line)

If your elements have different lengths, you could leverage .format():

lst = [["a","b","cde","d"],["e","f","g","h"],["i","j","k","l"]]

out = "\n".join(["".join("{:>5}".format(item) for item in sublst) for sublst in lst])
print(out)

Which would yield

a    b  cde    d
e    f    g    h
i    j    k    l

Upvotes: 6

vlad-ardelean
vlad-ardelean

Reputation: 7622

More one liners, for fun (Don't write code like this btw!)

with open('/tmp/my_file2.txt', 'w') as thefile: thefile.write('\n'.join(' '.join(el for el in l1) for sub in sub))

Upvotes: 1

Rahul
Rahul

Reputation: 11550

There's csv for that.

l = [["a","b","c","d"],["e","f","g","h"],["i","j","k","l"]]

with open("test.csv", 'w', encoding="utf-8", newline="") as f:
    writer = csv.writer(f, delimiter=' ')# or "\t", default is coma.
    writer.writerows(l)

Upvotes: 1

Youcef LAIDANI
Youcef LAIDANI

Reputation: 59978

To write in a file in that format you can use join like this :

array = [['a','b','c','d'],['e','f','g','h'],['i','j','k','l']]

# create a file if not exist and open it
file = open('testfile.txt', 'w')

# for each element in the array
for a in array: 
    # convert each sub list to a string, and write it in the file, note break line '\n'
    file.write(' '.join(a) + '\n') 

# close the file when you finish
file.close()

result :

write in a file

To avoid the break line in the end you can use :

breakLine = ''
for a in array:
    file.write(breakLine + ' '.join(a))
    # Use break line after the first write
    breakLine = '\n'
file.close()

result 2

write in a file

Upvotes: 2

George Dragan
George Dragan

Reputation: 119

Posting just to highlight the steps you need to take

l = [['a','b','c','d'], ['e', 'f', 'g', 'h'], ['i', 'j', 'k', 'l']]
with open('my_file.txt', 'w') as f:
    for sub_list in l:
        for elem in sub_list:
            f.write(elem + ' ')
        f.write('\n')

Upvotes: 4

0xc0de
0xc0de

Reputation: 8287

You can use list comprehension with newline:

'\n'.join(' '.join(item) for item in ls)

Upvotes: 4

Related Questions