我想制作一个 numpy 数组

Question

As the title says I want to make a numpy array.

array=np.random.randint(2,size=(4,4))

First question, at this time I want to make code that size can be changeable. What should I do?

top = input("Top(k):")

Second question, I want to receive k value like this and send output as much as this value. At this time, I wanna print the top k-row indexes from the weakest to the strongest (weakest:smaller number of ones) How to do it??:(

example like this.

input

[[1,0,0,0],
[1,1,1,1],
[1,0,0,0],
[1,0,0,0]]

Top(k):2

output

0,2

if Top(k):4, output is

0,2,3,1

Answer 1

Numpy uses static arrays (it is implemented in C), you cannot change the size of a numpy array as you would with python lists. However, you can use the numpy.ndarray constructor to create a numpy array from python list: array = numpy.ndarray(my_python_array) .

For you second answer you can use the function sum() of ndarray and use it like this:

histogram = []
for i in range(len(array_2D)):
    # Store the row indexes as well as number of ones
    histogram.append((i, array2D[i].sum())) 

# Sort regarding the number of ones
histogram.sort(key=lambda e:e[1]) 
for index, val in histogram[:k]:
    print(index, end=" ")

Here array2D is the numpy array you got from user input. You should parse the user input to get a numpy array before executing this code.