如何在python中使用for循环创建NXN矩阵

Question

I am kind new to python, and trying to create a dice example for CLT (central limit theory) as follows

import numpy as np
import matplotlib.mlab as mlab
import matplotlib.pyplot as plt

SampleSize=1000000
NumberofDice=2

Dice=np.zeros([SampleSize,NumberofDice])

for i in range(NumberofDice+1):
 Dice[:,i]=np.random.randint(1,7,SampleSize)

but I had an error saying

Traceback (most recent call last): File "", line 11, in IndexError: index 2 is out of bounds for axis 1 with size 2

I am not sure how to deal with it, basically I want to create a 2 X 1000000 matrix, and each row is an independent rolling dice process.

Can anyone help?

Answer 1

range(NumberofDice+1) just remove that +1 , numpy indexing is 0 to n-1 , not 1 to n , and range also follows that convention.

By the way you could do it directly like so too:

Dice = np.random.randint(1,7,size=(SampleSize,NumberofDice))