Converting a list of tuples into a list of strings

Question

So I have a list of tuples, for example [('GGG',), ('AAA',), ('BBB',)] and I want to convert it into a list of strings: ['GGG' , 'AAA', 'BBB'] .

I have tried using a for loop with the join method but cannot get it to work. Any help would be appreciated, Thanks.

Answer 1

Use chain.from_iterable from itertools

eg

from itertools import chain
x = [('GGG',), ('AAA',), ('BBB',)]
print(list(chain.from_iterable(x)))

output

['GGG', 'AAA', 'BBB']

The use of list is only to allow printing the output. It forces the lazy object returned from chain.from_iterable to be evaluated immediately. You don't need it if you will later iterate over object.

Answer 2

There are multiple ways you can achieve this. If array is z = [('GGG',), ('AAA',), ('BBB',)] , then:

1) Using zip : list(list(zip(*z))[0])

well the other ways have been just written by the other two most recent answers :).

Also, even though it was not asked, but I got interested in performance, and I wanted to share the results of a rather simple benchmark:

Input

z = [('aaa',) for i in range(10000)]

@Paul Rooney

%timeit itertools.chain.from_iterable(z)
# 129 ns ± 2.52 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

@COLDSPEED

%timeit [x[0] for x in z]
# 254 µs ± 1.34 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

@this

%timeit list(zip(*z))[0]
# 272 µs ± 794 ns per loop (mean ± std. dev. of 7 runs, 1000 loops each)

@mentalita

%timeit [str(*x) for x in z]
# 809 µs ± 904 ns per loop (mean ± std. dev. of 7 runs, 1000 loops each)

Answer 3

Use a simple list comprehension:

>>> my_list_of_tuples = [('GGG',), ('AAA',), ('BBB',)]
>>> my_list_of_strings = [str(*x) for x in my_list_of_tuples]
>>> my_list_of_strings
['GGG', 'AAA', 'BBB']

Answer 4

t=[('GGG',), ('AAA',), ('BBB',)]
str=[]
for each in t:
    str.append(each[0])
print str

Above one gives list of strings

Answer 5

you can just use itertools chain method tested in python2 & python3

from itertools import chain
data = [('GGG',), ('AAA',), ('BBB',)]
for item in itertools.chain(*data):
    print(item)

The itertools.chain method returns chain object, you can get elements using list or iterate using for .

Answer 6

You can use 'isinstance ' or type()==tuple method can done the job in just one line using list comprehension :

 print([j for i in your_list for j in i if isinstance(i,tuple)])

:)