Member Avatar for nish88

hi everybody..... i'm using an array to make a program but i'm not able to find the size (length) of the array.can anyone tell me how to do this?

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As noted, the right answer depends on what you mean by "array" — different containers expose different metadata. The short version: built‑in sequences give you the length of the outer container, numeric array libraries store shape/metadata, and generators/iterators don’t expose a length at all. Here are a few practical points and small snippets that fill gaps users often run into.

For NumPy ndarrays you can ask the array for more than just its dimensions — there are attributes that tell you the total element count, how many axes it has, and how many bytes the data buffer consumes:

# given a NumPy ndarray 'a'
a.size     # total number of elements
a.ndim     # number of dimensions (axes)
a.nbytes   # bytes used by the underlying data buffer

For Python lists a single length call reports the outer list only. If you have a 2D list and want the grand total of inner elements, flattening or summing inner lengths works. Example using itertools and a small recursive alternative for irregular nesting:

from itertools import chain
total = sum(1 for _ in chain.from_iterable(matrix))

def deep_count(seq):
    return sum(deep_count(x) if isinstance(x, list) else 1 for x in seq)

Quick tips: len-like queries on dicts count keys; generators need to be consumed to count items (so be careful with memory); sys.getsizeof shows object overhead, not deep memory use; NumPy attributes are O(1) (metadata), whereas flattening or iterating to count is O(n). If you’re doing numeric work at scale, converting data to NumPy early makes shape/size queries and bulk operations simpler and much faster.

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Member Avatar for BearofNH

If you mean an array in the numpy sense. e.g., z = numpy.zeros([5,3],float) then the shape attribute is what you want, e.g. z.shape returns (5,3).

If you're implementing an array as a Python list, then len(z) is what you want.

commented: nice help +7
Member Avatar for nish88

thanks you very much.its what i wanted.....

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