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this generator flattens nested containers such as
<code> l=( (1,23), [[[[42,(5,23)]]]])</code>
so that
<code> for i in flatten(l): print i</code>
gives you 1,23,42,5,23
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27 | def flatten(*args):
for arg in args:
try:
for i in arg:
for l in flatten(i):
yield l
except TypeError,e: yield arg
#---
# if you dislike the try and exception type of programming (which is
# usually a bit dangerous as it may hide a valid exception), you
# could instead do:
for arg in args:
if type(arg) in (type(()),type([])):
for elem in arg:
for f in flatten(elem):
yield f
else: yield arg
# which is obviously restricted to lists and tuples and does
# not work with user defined containers.
# note that you pass more than one container to flatten and
# all elements of every containers will yielded.
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Checking for other sequence types. You can use the 'types' module to check for other sequence types e.g.
-Hemanth (hemanth_sethuram at yahoo dot com)
This function won't work if a string occurs anywhere within its argument(s). A string's elements are strings, so flatten recurs infinitely if it encounters a string in the structure it is flattening. Having no string element type is one of Python's warts, and the author of this recipie has just stumbled over it.