您如何从Python列表中选择“ x”个唯一数字？

我需要从列表中挑选出“ x”个非重复的随机数。 例如：

all_data = [1, 2, 2, 3, 4, 5, 6, 7, 8, 8, 9, 10, 11, 11, 12, 13, 14, 15, 15]

我该如何选择像[2, 11, 15]这样的列表，而不是[3, 8, 8]？

George asked 2020-07-03T14:28:56Z

6个解决方案

74 votes

这正是random.sample()所做的。

>>> random.sample(range(1, 16), 3)

[11, 10, 2]

编辑：我几乎可以肯定这不是您要的，但是我被迫加入此注释：如果要从中进行采样的总体中包含重复项，则必须先将其删除：

population = [1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1]

population = set(population)

samples = random.sample(population, 3)

Sven Marnach answered 2020-07-03T14:29:18Z

4 votes

像这样：

all_data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]

from random import shuffle

shuffle(all_data)

res = all_data[:3]# or any other number of items

要么：

from random import sample

number_of_items = 4

sample(all_data, number_of_items)

如果all_data可能包含重复项，则需要修改代码以先删除重复项，然后使用shuffle或sample：

all_data = list(set(all_data))

shuffle(all_data)

res = all_data[:3]# or any other number of items

Artsiom Rudzenka answered 2020-07-03T14:29:47Z

4 votes

其他人建议您使用random.sample。虽然这是一个有效的建议，但每个人都忽略了一个细微之处：

如果总体中包含重复项， 那么每次发生都是可能的 样本中的选择。

因此，您需要将列表变成一个集合，以避免重复的值：

import random

L = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]

random.sample(set(L), x) # where x is the number of samples that you want

inspectorG4dget answered 2020-07-03T14:30:16Z

1 votes

当然，对于所有解决方案，另一种方式是必须确保原始列表中至少有3个唯一值。all_data = [1,2,2,3,4,5,6,7,8,8,9,10,11,11,12,13,14,15,15]

choices = []

while len(choices) < 3:

selection = random.choice(all_data)

if selection not in choices:

choices.append(selection)

print choices

Joe answered 2020-07-03T14:30:36Z

1 votes

您还可以使用itertools.combinations和random.shuffle生成随机选择列表。

all_data = [1,2,2,3,4,5,6,7,8,8,9,10,11,11,12,13,14,15,15]

# Remove duplicates

unique_data = set(all_data)

# Generate a list of combinations of three elements

list_of_three = list(itertools.combinations(unique_data, 3))

# Shuffle the list of combinations of three elements

random.shuffle(list_of_three)

输出：

[(2, 5, 15), (11, 13, 15), (3, 10, 15), (1, 6, 9), (1, 7, 8), ...]

riza answered 2020-07-03T14:31:00Z

0 votes

import random

fruits_in_store = ['apple','mango','orange','pineapple','fig','grapes','guava','litchi','almond']

print('items available in store :')

print(fruits_in_store)

my_cart = []

for i in range(4):

#selecting a random index

temp = int(random.random()*len(fruits_in_store))

# adding element at random index to new list

my_cart.append(fruits_in_store[temp])

# removing the add element from original list

fruits_in_store.pop(temp)

print('items successfully added to cart:')

print(my_cart)

Output:

items available in store :

['apple', 'mango', 'orange', 'pineapple', 'fig', 'grapes', 'guava', 'litchi', 'almond']

items successfully added to cart:

['orange', 'pineapple', 'mango', 'almond']

Shashank Rautela answered 2020-07-03T14:32:16Z

满意答案

litielige

2016.11.20

采纳率：48%    等级：7

已帮助：515人

#include

long fun(long s)

{

int sum = 0;

long fin = 0,flag = 0;

int a[20] = {0};

for(int i =1; (s/i) != 0; i = i * 10)

++sum;

int temp = i;

for(int j = 0; j < sum; j++)

{

temp = temp / 10;

a[j] = s / temp;

s = s % temp;

}

for(int k = 0; a[k] >= 0; k++)

{

for(j = 0; j < sum-k-1; j++)

{

if(a[j] > a[j+1])

{

int t;

t = a[j];

a[j] = a[j+1];

a[j+1] = t;

}

}

}

j = 0;

i = 1;

while(j < sum)

{

if(a[j] % 2 == 0)

{

if(a[j] == 0)

{

if(j == 0) ;

else

{

flag = 1;

fin = i*10;

}

}

else

if(flag)

{

fin *= a[j];

flag = 0;

}

else

fin += a[j] * i;

i *= 10;

}

j++;

}

return fin;

}

int main()

{

long s,final ;

scanf("%ld",&s);

final = fun(s);

printf("%ld\n",final);

return 0;

}

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