Split a list to individual entries

I am extracting some emails from a CSV file and then saving it to another CSV file.

email variable should be in this format:

email = ['email@email.com'], ['email2@company.com'], ['e开发者_StackOverflow社区mail3@company2.com']

but in certain cases it will be returned as:

email = ['email@email.com', 'email2@email.com'], ['email3@email.com']

In certain rows it finds 2 emails, so that is when it is presented like this.

What would be an efficient way to change it??

The next should be quite efficient:

>>> import itertools
>>> data = [ ['email@email.com', 'email2@email.com'], ['email3@email.com'] ]
>>> [[i] for i in itertools.chain(*data)]
[['email@email.com'], ['email2@email.com'], ['email3@email.com']]

data = [ ['email@email.com', 'email2@email.com'], ['email3@email.com'] ]

def flatten(data):
    for item in data:
        if isinstance(item, basestring):
            yield item
        else:
            for i in item:
                yield [i]

or, if you want to support arbitrary levels of nesting:

def flatten(data):
    for item in data:
        if isinstance(item, basestring):
            yield [item]
        else:
            for i in flatten(item):
                yield i

If you only need a list of emails, without each element wrapped in a list (which seems more reasonable to me), the solution is much simpler:

import itertools
print list(itertools.chain.from_iterable(data))

If you are working with CSV files you may want to try the CSV module from the standard library. http://docs.python.org/library/csv.html

Example:

$ cat > test.csv
['email@email.com', 'email2@email.com'], ['email3@email.com']

$ python
>>> import csv
>>> reader = csv.reader(open('test.csv', 'r'))
>>> for row in reader:
...     print row
... 
["['email@email.com'", " 'email2@email.com']", " ['email3@email.com']"]

What I did there may not be what you want but if you look at the library you might find what you need.