python create array of size n with value 0

How to declare array of zeros in python (or an array of a certain size) [duplicate]

stackoverflow.com › questions › 4056768 › how-to-declare-array-of-zeros-in-python-or-an-array-of-a-certain-size

Copybuckets = [0] * 100

Careful - this technique doesn't generalize to multidimensional arrays or lists of lists. Which leads to the List of lists changes reflected across sublists unexpectedly problem

Answer from dan04 on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 4056768 › how-to-declare-array-of-zeros-in-python-or-an-array-of-a-certain-size

How to declare array of zeros in python (or an array of a certain size) - Stack Overflow

Top answer

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534

Copybuckets = [0] * 100

Careful - this technique doesn't generalize to multidimensional arrays or lists of lists. Which leads to the List of lists changes reflected across sublists unexpectedly problem

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Just for completeness: To declare a multidimensional list of zeros in python you have to use a list comprehension like this:

Copybuckets = [[0 for col in range(5)] for row in range(10)]

to avoid reference sharing between the rows.

This looks more clumsy than chester1000's code, but is essential if the values are supposed to be changed later. See the Python FAQ for more details.

GeeksforGeeks

geeksforgeeks.org › python › how-to-create-an-array-of-zeros-in-python

How to create an array of zeros in Python? - GeeksforGeeks

July 23, 2025 - Explanation: This code creates a list of 1000 zeros by multiplying [0] with 1000. itertools.repeat() generates an iterator that produces the same value repeatedly. When converted to a list, it creates a zero-filled list efficiently. It’s memory-friendly and useful for large sequences or when lazy evaluation is needed.

Discussions

How should I initialize a numpy array of NaN values?

>>> np.full(3, np.nan) But the bigger question is why would you want to? Edit: as an explanation, your example does not work because you initialized an array of ints. ints have no "NaN" value, only floats do. So your method would work if you initialized an array of floats: >>> x = np.array([0.0,0.0,0.0]) >>> x.fill(np.nan) >>> x array([ nan, nan, nan]) Or converted the ints to floats: >>> x = np.array([0,0,0], dtype=np.float) >>> x.fill(np.nan) >>> x array([ nan, nan, nan]) But the np.full() method is much better. More on reddit.com

r/learnpython

April 8, 2016

i can create a list from 0 to n-1 by "doing list(range(0,n))", however this doesn't work if i define a variable "list", e.g "list = 0". why do python allow us to use the word "list" as a variable if it has other purposes?

list converts its argument to a list. A few examples: list("abc") gives `['a', 'b', 'c'] list( (1, 2, 3) ) gives[1, 2, 3]` list( [1, 2, 3] ) gives[1, 2, 3]`, i.e., it makes a copy. One reason to allow variable shadowing (= reusing an existing identifier in a new scope, such as list in your case) is that without it, new additions could cause existing code to break. Say I write def foo(ns): avg = sum(ns) / len(ns) ... If, for some reason, avg were added as a built-in function, my code would become incorrect. In general, once a piece of code X works as intended, it should not be possible that new code (outside of X) causes X to fail. More on reddit.com

r/learnpython

September 29, 2022

Creating an array who size and values depend on another array's values being put through a function

Since you mention arrays and arange, I presume you're using Numpy. The way to create one array by applying a function to each element from another array is by using vectorize . More on reddit.com

r/learnpython

May 21, 2022

Why is getting the length of an array O(1) and not O(n)?

Most implementations store the length of an array in the object itself. Whenever you insert/remove it gets updated. Thus you're not iterating to get the length you're just getting a value. More on reddit.com

r/learnprogramming

November 7, 2022

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