Oct 3, 2009 · @AndersonGreen As I said there's no such thing as a variable declaration in Python. You would create a multidimensional list by taking an empty list and putting other lists inside it or, if the dimensions of the list are known at write-time, you could just write it as a literal like this: my_2x2_list = [[a, b], [c, d]].

As @Arnab and @Mike pointed out, an array is not a list. Few differences are 1) arrays are fixed size during initialization 2) arrays normally support lesser operations than a list. Maybe an overkill in most cases, but here is a basic 2d array implementation that leverages hardware array implementation using python ctypes(c libraries)

One thing to note: all elements in the list will have initially the same id (or memory address). When you change any element later on in the code, this will impact only the specified value, - HOWEVER - if you create a list of custom objects in this way (using the int multiplier) and later on you change any property of the custom object, this will change ALL the objects in the list.

Edit: If you don't know the size of big_array in advance, it's generally best to first build a Python list using append, and when you have everything collected in the list, convert this list to a numpy array using numpy.array(mylist). The reason for this is that lists are meant to grow very efficiently and quickly, whereas numpy.concatenate ...

The question says "How to declare array of zeros ..." but then the sample code references the Python list: buckets = [] # this is a list However, if someone is actually wanting to initialize an array, I suggest: from array import array my_arr = array('I', [0] * count) The Python purist might claim this is not pythonic and suggest:

Jun 3, 2014 · How to initialize a Multi-Dimensional Array in Python? 5. Declaring and populating 2D array in python. 2.

Mar 31, 2012 · Initializing 2D array in Python. Ask Question Asked 13 years, 1 month ago. Modified 2 years, 3 months ago. ...

To create an empty multidimensional array in NumPy (e.g. a 2D array m*n to store your matrix), in case you don't know m how many rows you will append and don't care about the computational cost Stephen Simmons mentioned (namely re-buildinging the array at each append), you can squeeze to 0 the dimension to which you want to append to: X = np.empty(shape=[0, n]).

Dec 19, 2011 · I want to initialize an array with 10 values starting at X and incrementing by Y. I cannot directly use range() as it requires to give the maximum value, not the number of values. I can do this in a loop, as follows: a = [] v = X for i in range(10): a.append(v) v = v + Y But I'm certain there's a cute python one liner to do this ...

Feb 7, 2009 · import array verts=array.array('i',(0,)*1000) For the non-pythonistas, the (0,)*1000 term is creating a tuple containing 1000 zeros. The comma forces python to recognise (0) as a tuple, otherwise it would be evaluated as 0. I've used a tuple instead of a list because they are generally have lower overhead.