Jul 12, 2011 · I want to define a two-dimensional array without an initialized length like this: Matrix = [][] But this gives an error: IndexError: list index out of range

@codemuncher The reason that [[0] * col] * row doesn't do what you want is because when you initialize a 2d list that way, Python will not create distinct copies of each row. Instead it will init the outer list …

2 When constructing multi-dimensional lists in Python I usually use something similar to ThiefMaster's solution, but rather than appending items to index 0, then appending items to index 1, etc., I always …

3 If you are concerned about memory footprint, the Python standard library contains the array module; these arrays contain elements of the same type.

105 If you wish to combine two 10 element one-dimensional arrays into a two-dimensional array, np.vstack((tp, fp)).T will do it. np.vstack((tp, fp)) will return an array of shape (2, 10), and the T …

Jun 8, 2014 · I know that an easy way to create a NxN array full of zeroes in Python is with:

I want to create an empty array and append items to it, one at a time. xs = [] for item in data: xs.append(item) Can I use this list-style notation with NumPy arrays?

I need to make a multidimensional array of zeros. For two (D=2) or three (D=3) dimensions, this is easy and I'd use: a = numpy.zeros(shape=(n,n)) or a = numpy.zeros(shape=(n,n,n)) How for I for

I want to create a 2D array of values from the third row based on their x,y coordinates in the file. I read in each column as an individual array, and I created grids of x values and y values using …

Jul 31, 2017 · 6 I am using Python 3 and am trying to create 2D integer arrays of a known and fixed size. How can I do this? The arrays I have in mind are the Python-provided array.array, although I am not …