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Making a flat list out of list of lists in Python
I am trying to find an easy way to turn a multi dimensional (nested) python list into a single list, that contains all the elements of sub lists.
For example:
A = [[1,2,3,4,5]] turns to
A = [1,2,3,4,5] or
A = [[1,2], [3,4]] turns to
A = [1,2,3,4] 
653
Flatten the list to "remove the brackets" using a nested list comprehension. This will un-nest each list stored in your list of lists!
Flatten List of Lists Using itertools (chain()) This approach is ideal for transforming a 2-D list into a single flat list as it treats consecutive sequences as a single sequence by iterating through the iterable passed as the argument in a sequential manner.
Use itertools.chain:
itertools.chain(*iterables):Make an iterator that returns elements from the first iterable until it is exhausted, then proceeds to the next iterable, until all of the iterables are exhausted. Used for treating consecutive sequences as a single sequence.
Example:
from itertools import chain A = [[1,2], [3,4]] print list(chain(*A)) # or better: (available since Python 2.6) print list(chain.from_iterable(A)) The output is:
[1, 2, 3, 4] [1, 2, 3, 4] If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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