Create a Matrix with random position

问题:

I am creating a matrix with this

def letsplay(m,n):
    matrix = [[ '.' for m in range(10)] for n in range(10)]
    for sublist in matrix:
        s = str(sublist)
        s = s.replace('[', '|').replace(']', '|').replace(',', "")
        print(s)

that returns

>>> '.'.'.'.'.'.'.'.'.'.'
    '.'.'.'.'.'.'.'.'.'.'
    ...
    ...

That creats a matrix 10x10. and Now I want to add within the matrix to random position with a probability = prob, the prob should be entered by the user, and return for the random posstions a 'N'.

回答1:

How about using a probability matrix:

probs = numpy.random.random_sample((10, 10))
data = numpy.empty(probs.shape, dtype='S1')
data.fill('.')
data[probs < threshold] = 'N'

where threshold is a variable that you choose, for example, 0.05 for a 5% chance.

回答2:

Not quite sure what prob=5 would mean, probabilities range from 0 to 1? I think there's two parts to your question.

• change a random element of the matrix

  matrix[random.randrange(10)][random.randrange(10)] = 'N'

• have a number of elements changed in the matrix, based on a probability.

  import random
  prob = 0.01
  numNs = prob*10*10 # because e.g. 1% chance in 10x10 matrix = 1 field
  for i in range(numNs):   
    changed = False   
    while not changed:
      x = random.randrange(10)
      y = random.randrange(10)
      if not matrix[x][y] == 'N': # if not already changed
        matrix[x][y] = 'N'
        changed = True