I'm currently trying to learn Numpy and Python. Given the following array:
import numpy as np
a = np.array([[1,2],[1,2]])
Is there a function that returns the dimensions of a (e.g.a is a 2 by 2 array)?
size() returns 4 and that doesn't help very much....

Asked By morgan freeman

In Python, is the following the only way to get the number of elements?
arr.__len__()
If so, why the strange syntax?

Asked By Joan Venge

How can I count the number of elements in an array, because contrary to logic array.count(string) does not count all the elements in the array, it just searches for the number of occurrences of string.

Asked By UnkwnTech

I have created an array thusly:
import numpy as np
data = np.zeros( (512,512,3), dtype=np.uint8)
data[256,256] = [255,0,0]
What I want this to do is display a single red dot in the center of a 512x512 image. (At least to begin with... I think I can fig...

Asked By jlswint

If you are creating a 1d array, you can implement it as a List, or else use the 'array' module in the standard library. I have always used Lists for 1d arrays.
What is the reason or circumstance where I would want to use the array module instead?
Is it...

Asked By Corey Goldberg

What's the easiest way to shuffle an array with python?

Asked By davethegr8

How can I sort an array in NumPy by the nth column?
For example,
a = array([[9, 2, 3],
[4, 5, 6],
[7, 0, 5]])
I'd like to sort rows by the second column, such that I get back:
array([[7, 0, 5],
[9, 2, 3],
[4, 5, 6]...

Asked By user248237

When I print a numpy array, I get a truncated representation, but I want the full array.
Is there any way to do this?
Examples:
>>> numpy.arange(10000)
array([ 0, 1, 2, ..., 9997, 9998, 9999])
>>> numpy.arange(10000).reshape...

Asked By kame

What are the advantages of NumPy over regular Python lists?
I have approximately 100 financial markets series, and I am going to create a cube array of 100x100x100 = 1 million cells. I will be regressing (3-variable) each x with each y and z, to fill the...

Asked By Thomas Browne

I am using numpy. I have a matrix with 1 column and N rows and I want to get an array from with N elements.
For example, if i have M = matrix([[1], [2], [3], [4]]), I want to get A = array([1,2,3,4]).
To achieve it, I use A = np.array(M.T)[0]. Does anyo...

Asked By yassin

How do I declare an array in Python?
I can't find any reference to arrays in the documentation.

Asked By pynewbie

Does anybody know how to extract a column from a multi-dimensional array in Python?

Asked By jaweria

What's the best way to create 2D arrays in Python?
What I want is want is to store values like this:
X , Y , Z
so that I access data like X[2],Y[2],Z[2] or X[n],Y[n],Z[n] where n is variable.
I don't know in the beginning how big n would be so I would...

Asked By spring liu

Anyone know of a simple library or function to parse a csv encoded string and turn it into an array or dictionary?
I don't think I want the built in csv module because in all the examples I've seen that takes filepaths, not strings.

Asked By Drew LeSueur

Right now I am using a list, and was expecting something like:
verts = list (1000)
Should I use array instead?

Asked By Joan Venge

How can I convert a string of bytes into an int in python?
Say like this: 'y\xcc\xa6\xbb'
I came up with a clever/stupid way of doing it:
sum(ord(c) << (i * 8) for i, c in enumerate('y\xcc\xa6\xbb'[::-1]))
I know there has to be something buil...

Asked By ʞɔıu

It should not be so hard. I mean in C,
int a[10];
is all you need. How to create an array of all zeros for a random size. I know the zeros() function in NumPy but there must be an easy way built-in, not another module.

Asked By PythontoBeLoved

After doing some processing on an audio or image array, it needs to be normalized within a range before it can be written back to a file. This can be done like so:
# Normalize audio channels to between -1.0 and +1.0
audio[:,0] = audio[:,0]/abs(audio[:,0...

Asked By endolith

I can't figure out how to use an array or matrix in the way that I would normally use a list. I want to create an empty array (or matrix) and then add one column (or row) to it at a time.
At the moment the only way I can find to do this is like:
mat = N...

Asked By Ben

I know there is a method for a Python list to return the first index of something:
>>> l = [1, 2, 3]
>>> l.index(2)
1
Is there something like that for NumPy arrays?

Asked By Nope