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+--- Thread: Why I get RecursionError on very small amount of data? (/thread-12014.html)
Why I get RecursionError on very small amount of data? - wavic - Aug-05-2018
I can't imagine how is possible to get this error when I use the function on such a small data
How is that even possible?
In [1]: l = [list(word) for word in 'Something goes wrong'.split()]
In [2]: def flatten(iterable):
...: iterator = iter(iterable)
...: for item in iterator:
...: if '__iter__' in dir(item):
...: yield from flatten(item)
...: else:
...: yield item
...:
In [3]: flat = [item for item in flatten(l)]
---------------------------------------------------------------------------
RecursionError Traceback (most recent call last)
<ipython-input-3-930115f14cc4> in <module>()
----> 1 flat = [item for item in flatten(l)]
<ipython-input-3-930115f14cc4> in <listcomp>(.0)
----> 1 flat = [item for item in flatten(l)]
<ipython-input-2-7311442c70ce> in flatten(iterable)
3 for item in iterator:
4 if '__iter__' in dir(item):
----> 5 yield from flatten(item)
6 else:
7 yield item
... last 1 frames repeated, from the frame below ...
<ipython-input-2-7311442c70ce> in flatten(iterable)
3 for item in iterator:
4 if '__iter__' in dir(item):
----> 5 yield from flatten(item)
6 else:
7 yield item
RecursionError: maximum recursion depth exceeded while calling a Python object
In [4]:
In [4]: flat = [item for item in flatten(l)]
---------------------------------------------------------------------------
RecursionError Traceback (most recent call last)
<ipython-input-4-930115f14cc4> in <module>()
----> 1 flat = [item for item in flatten(l)]
<ipython-input-4-930115f14cc4> in <listcomp>(.0)
----> 1 flat = [item for item in flatten(l)]
<ipython-input-2-7311442c70ce> in flatten(iterable)
3 for item in iterator:
4 if '__iter__' in dir(item):
----> 5 yield from flatten(item)
6 else:
7 yield item
... last 1 frames repeated, from the frame below ...
<ipython-input-2-7311442c70ce> in flatten(iterable)
3 for item in iterator:
4 if '__iter__' in dir(item):
----> 5 yield from flatten(item)
6 else:
7 yield item
RecursionError: maximum recursion depth exceeded while calling a Python object
In [5]:
RE: Why I get RecursionError on very small amount of data? - micseydel - Aug-05-2018
Without having dug into it, I would imagine it's because your base case is characters, which are length-1 strings, which are iterable. I expect it would work if the smallest elements are scalars (e.g int).
RE: Why I get RecursionError on very small amount of data? - wavic - Aug-05-2018
Hm! I have tried it with integers and it worked. It's strange to me.
sys.getrecursionlimit() says that it is 1000.
How it happens if an element is a string ( iterable) this limit is reached? This is not happening during code execution I suppose.
RE: Why I get RecursionError on very small amount of data? - micseydel - Aug-05-2018
(Aug-05-2018, 04:48 PM)wavic Wrote: How it happens if an element is a string ( iterable) this limit is reached?
Output:>>> '__iter__' in dir('c')
True