How do I flatten nested lists in Python?

Question

My List is :

 [['kukatpally'], ['gachibowli'], ['Madhapur'], ['Chintal'],........]

I want to show like this

 ['kukatpally', 'gachibowli', 'Madhapur', 'Chintal',....]

so how to delete those '[' and ']' symbols..

Thanks in advance

then, please accept one that you think the most suitable answer. click on the tick next to the answer. — Buddhima Gamlath
– Buddhima Gamlath, Commented Dec 27, 2013 at 9:01
Please be aware that "those symbols" are not in the list. They just show up when you print a representation of the list. — Matthias
– Matthias, Commented Dec 27, 2013 at 9:09

Danstahr · Accepted Answer · 2013-12-27 08:58:46Z

4

Use itertools.chain :

import itertools

l = [['kukatpally', 'somethingelse'], ['gachibowli'], ['Madhapur'], ['Chintal']]

list(itertools.chain(*l))
>> ['kukatpally', 'somethingelse', 'gachibowli', 'Madhapur', 'Chintal']

Or itertools.chain.from_iterable

import itertools

l = [['kukatpally', 'somethingelse'], ['gachibowli'], ['Madhapur'], ['Chintal']]

list(itertools.chain.from_iterable(l))
>> ['kukatpally', 'somethingelse', 'gachibowli', 'Madhapur', 'Chintal']

answered Dec 27, 2013 at 8:58

Danstahr

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Comments

David Neale · Accepted Answer · 2013-12-27 08:57:45Z

3

Assuming you meant that your sub lists might contain multiple items:

 >>> ls = [['kukatpally'], ['gachibowli'], ['Madhapur'], ['Chintal']]
 >>> new_list = [item for sublist in ls for item in sublist]
 >>> new_list
 ['kukatpally', 'gachibowli', 'Madhapur', 'Chintal']

answered Dec 27, 2013 at 8:57

David Neale

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Comments

gefei · Accepted Answer · 2013-12-27 08:52:44Z

1

>>> ls = [['kukatpally'], ['gachibowli'], ['Madhapur'], ['Chintal']]
>>> l = [x[0] for x in ls]
>>> l
['kukatpally', 'gachibowli', 'Madhapur', 'Chintal']
>>>

answered Dec 27, 2013 at 8:52

gefei

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Paul Yin · Accepted Answer · 2013-12-27 08:52:47Z

0

new_list = [item[0] for item in old_list]

answered Dec 27, 2013 at 8:52

Paul Yin

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