Creating a 3x4 random integers from 0-100 array-CodePudding

It is an exercise from a crash course in numpy in Python from Google. I've looked at the solution, but I want to know if there's a way to solve my error, and complete the exercise the way I tried at first.

I have tried this:

rand_0_100 = np.random.randint(low=0, high=101, size=(12))
my_data = np.array(
    [rand_0_100[0], rand_0_100[1], rand_0_100[2], rand_0_100[3]], 
    [rand_0_100[4], rand_0_100[5], rand_0_100[6], rand_0_100[7]], 
    [rand_0_100[8]],
    [rand_0_100[9], rand_0_100[10], rand_0_100[11]]
)

... and I get this error:

TypeError: array() takes from 1 to 2 positional arguments but 4 were given

Looking at the solution, I now know I can make the random number from 0-100 an array, by modifying the size argument to (3, 4), but I'd like to know if it is possible to make the array the way I tried.

CodePudding user response：

Yes, that is possible, but you will need to pass a single 2-dimensional list to np.array, not four 1-dimensional lists:

import numpy as np

rand_0_100 = np.random.randint(low=0, high=101, size=(12))

out = np.array([ # <<< Note this opening [
    [rand_0_100[0], rand_0_100[1], rand_0_100[2],  rand_0_100[3] ],
    [rand_0_100[4], rand_0_100[5], rand_0_100[6],  rand_0_100[7] ],
    [rand_0_100[8], rand_0_100[9], rand_0_100[10], rand_0_100[11]]
]) # <<< and this closing ]

Numpy also provides a clean way to do this for you using reshape:

out = rand_0_100.reshape(3, 4)

But as you mention, the best way is to simply pass size=(3, 4) to randint.

CodePudding user response：

by the way for the original problem you can have a matrix of 3*4 by this approach :

rand_0_100 =np.random.randint(low=0, high=101, size=(12))
my_data =rand_0_100 .reshape(3,4)

np.array get the arguments as below:

numpy.array(object, dtype=None, *, copy=True, order='K', subok=False, ndmin=0, like=None)

object : is the array you pass to it.

dtype : The desired data-type for the array. If not given, then the type will be determined as the minimum type required to hold the objects in the sequence.

copy :If true (default), then the object is copied. Otherwise, a copy will only be made if array returns a copy

order: Specify the memory layout of the array.

in your code you gave 4 list as argument to the function. that's why your program face the error

TypeError: array() takes from 1 to 2 positional arguments but 4 were given

hope it helps.