Question

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Convert list of tuples to list?

I have a list like this

[('Knightriders',), ('The Black Knight',), ('Fly by Knight',), ('An Arabian Knight',), ('A Bold, Bad Knight',)...]

I want to convert this to :

['Knightriders', 'The Black Knight', 'Fly by Knight', 'An Arabian Knight', 'A Bold, Bad Knight',...]

What is the least time consuming way to accomplish this ?

Answer 1

simplest one is using a list comprehension:

In [126]: lis=[('Knightriders',), ('The Black Knight',), ('Fly by Knight',), ('An Arabian Knight',), ('A Bold, Bad Knight',)]

In [127]: [x[0] for x in lis]
Out[127]: 
['Knightriders',
 'The Black Knight',
 'Fly by Knight',
 'An Arabian Knight',
 'A Bold, Bad Knight']

or using itemgetter:

In [128]: from operator import itemgetter

In [129]: list(map(itemgetter(0),lis))
Out[129]: 
['Knightriders',
 'The Black Knight',
 'Fly by Knight',
 'An Arabian Knight',
 'A Bold, Bad Knight']

or:

In [131]: [next(x) for x in map(iter,lis)]
Out[131]: 
['Knightriders',
 'The Black Knight',
 'Fly by Knight',
 'An Arabian Knight',
 'A Bold, Bad Knight']

or using zip() as suggested by @DSM:

In [132]: zip(*lis)[0]
Out[132]: 
('Knightriders',
 'The Black Knight',
 'Fly by Knight',
 'An Arabian Knight',
 'A Bold, Bad Knight')

or using ast.literal_eval(least recommended solution or may be never try this):

In [148]: from ast import literal_eval

In [149]: literal_eval(repr(lis).replace(",)",")"))
Out[149]: 
['Knightriders',
 'The Black Knight',
 'Fly by Knight',
 'An Arabian Knight',
 'A Bold, Bad Knight']