随机迭代Python中的2D列表

Question

My first attempt to accomplish this resulted in:

def rand_Random(self):
    randomRangeI = range(self.gridWidth)
    shuffle(randomRangeI)
    randomRangeJ = range(self.gridHeight)
    shuffle(randomRangeJ)

    for i in randomRangeI:
        for j in randomRangeJ:
            if self.grid[i][j] != 'b':
                print i, j
                self.grid[i][j].colour = self.rand_Land_Picker()

Which has the issue of going through one inner list at a time:

[1][1..X]

[2][1..X]

What I'd like to be able to do is iterate through the 2d array entirely at random (with no repeats).

Anyone have any solutions to this problem?

Edit: Thanks for the replies, it appears the way I view 2d arrays in my mind is different to most!

Answer 1

Create an array with all possible pairs of coordinates, shuffle this and iterate through as normal.

import random
coords = [(x,y) for x in range(self.gridWidth) for y in range(self.gridHeight)
random.shuffle(coords)
for i,j in coords:
    if self.grid[i][j] != 'b':
        print i, j
        self.grid[i][j].colour = self.rand_Land_Picker()

Answer 2

You can consider 2D array as 1D array and randomly iterate through it.

def rand_Random(self):
    randomRange = range(self.gridWidth*self.gridHeight)
    shuffle(randomRange)

    for index in randomRange:
        i = index / self.gridWidth
        j = index % self.gridWidth
        if self.grid[i][j] != 'b':
            print i, j
            self.grid[i][j].colour = self.rand_Land_Picker()

Answer 3

You can do something like:

randomRange = range(w*h)
shuffle(randomRange)

for n in randomRange:
    i = n/w
    j = n%w

Here randomRange basically enumerates all the coordinates from 0 to w*h-1 .

Even prettier, i and j , can be found in one statement:

i,j = divmod(n, w)