Bill Kranec wrote:
Hello,
I have a list of lists, for example [ [1,2] , [3,4] ], and I would
like to pass all the elements of that list as arguments to a function
(for example the intersection of all list elements). Is there a
command in regular Python to do this? I would like to avoid the
hassle and speed hit of a loop to extract all the list elements.
In the past, I believe I have used something like flatten(list), which
was part of Numarray (I think). Am I missing an obvious or clever
solution in regular Python?
Thanks for your help!
Bill
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Well, here's something i put together (works for lists and tuples,
ignores strings and dicts):
### Start Code ###
def flatten(sequence):
def rflat(seq2):
seq = []
for entry in seq2:
if '__contains__' in dir(entry) and \
type(entry) != str and \
type(entry)!=dict:
seq.extend([i for i in entry])
else:
seq.append(entry)
return seq
def seqin(sequence):
for i in sequence:
if '__contains__' in dir(i) and \
type(i) != str and \
type(i) != dict:
return True
return False
seq = sequence[:]
while seqin(seq):
seq = rflat(seq)
return seq
### End Code ###
Tested it on a few different scenarios, all performed as expected:
>>> flatten([1])
[1]
>>> flatten([1,[1]])
[1, 1]
>>> flatten(['ab',1])
['ab', 1]
>>> flatten([10,(34,42),54,'abc'])
[10, 34, 42, 54, 'abc']
>>> flatten([{'abc':[1,2,3]},[{'a':'1'},{'[1,2]':'ab'}]])
[{'abc': [1, 2, 3]}, {'a': '1'}, {'[1,2]': 'ab'}]
Cheers,
Orri
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Email: singingxduck AT gmail DOT com
AIM: singingxduck
Programming Python for the fun of it.
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