Writing lists to a file with some custom formatting

Question

I'm having some issues saving my lists to a file, the two ways in which I have tried have both yielded the undesired output.

The first way I tried was:

savefile.write(str(full_list))

returns:

[u'Smith', u'Malte Low', u'Day', u'George']

The other way I tried was:

for fitem in full_list:
    file.write(str(fitem))

returns:

SmithMalte LowDayGeorge

I am ideally looking for it to return:

Smith, Malte, Low, Day, George

I'm not quite sure how to use .join to make this work but it seems like the best option, I may be wrong.

Anyone got any ideas how I should be fixing this, it would be much appreciated.

Thanks in advance - Hy

Sukrit Kalra · Accepted Answer · 2013-08-10 01:41:15Z

2

You can use.

 ", ".join(full_list)

And then write the results to the file.

See the snippet -

>>> full_list = [u'Smith', u'Malte Low', u'Day', u'George']
>>> print ", ".join(full_list)
Smith, Malte Low, Day, George

EDIT - Just saw that you wanted a comma between Malte Low, then, you can just do

>>> from itertools import chain
>>> ", ".join(chain.from_iterable(map(str.split, full_list)))
u'Smith, Malte, Low, Day, George'

answered Jul 30, 2013 at 15:18

Sukrit Kalra

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1 Comment

Didn't know I could do that. Thanks. :)

Abhijit · Accepted Answer · 2013-07-30 15:26:17Z

Given the list

[u'Smith', u'Malte Low', u'Day', u'George']

You may try

savefile.write(','.join(full_list))

But that would simply return

Smith,Malte Low,Day,George

which may not be what you wan't as your desired output, delimits words and not the items by ','

So you may want to do

and then join back by comma

savefile.write(','.join(' '.join(full_list).split()))

But then you have to iterate multiple times. To perform the operation on a single iteration, you can use itertools.chain.from_iterable

from itertools import chain
savefile.write(','.join(itertools.chain.from_iterable(e.split()
                       for e in full_list)))