在python 3.x中随机打印不同的值

Question

from random import randint

result = []
colors = {1: "Red", 2: "Green", 3: "Blue", 4: "White"}

while True:
    for key in colors:
        ball = randint(1,4)
        probability = (ball/10)
        result.append(probability)

    break

print(result)

This code gives me 4 values which is ok, but I'd like to have no repetitions. So if program took eg "White", it won't include it to iteration. Any ideas?

Answer 1

If you have 4 values and you just want a random permutation of them, just use random.shuffle :

from random import shuffle

colors = {1: "Red", 2: "Green", 3: "Blue", 4: "White"}

balls = list(colors)
shuffle(balls)
result = [ball/10 for ball in balls]

print(result)

Another option (especially good with larger lists, because shuffling a list is "slow") is the use of random.sample :

from random import sample

colors = {1: "Red", 2: "Green", 3: "Blue", 4: "White"}

result = [ball/10 for ball in sample(colors, 4)]

print(result)

Answer 2

You can check whether that particular value has been taken or not.

list_taken = []
number = randint(1,n)
while number in list_taken:
    number = randint(1,n)
list_taken.append(number)

So what above 4 lines of code do is, maintain a list of already taken values and repeat finding new values until it gets a new one.

Hope this helps!