Python中的 random.shuffle()函数

shuffle()是 random 模块的内置方法。它用于打乱序列（列表）。改组意味着改变序列元素的位置。在这里，洗牌操作就位。

随机.shuffle()

Syntax : random.shuffle(sequence, function)

Parameters : 

• sequence : can be a list 
• function : optional and by default is random(). It should return a value between 0 and 1.

Returns : nothing 

示例 1：随机播放列表

Python3

# import the random module
import random
 
 
# declare a list
sample_list = ['A', 'B', 'C', 'D', 'E']
 
print("Original list : ")
print(sample_list)
 
# first shuffle
random.shuffle(sample_list)
print("\nAfter the first shuffle : ")
print(sample_list)
 
# second shuffle
random.shuffle(sample_list)
print("\nAfter the second shuffle : ")
print(sample_list)

输出 ：

Original list : 
['A', 'B', 'C', 'D', 'E']

After the first shuffle : 
['A', 'B', 'E', 'C', 'D']

After the second shuffle : 
['C', 'E', 'B', 'D', 'A']

shuffle() 方法不能用于对字符串等不可变数据类型进行混洗。

示例 2：

Python3

# import the random module
import random
 
 
# user defined function to shuffle
def sample_function():
    return 0.5
 
sample_list = ['A', 'B', 'C', 'D', 'E']
print("Original list : ")
print(sample_list)
 
# as sample_function returns the same value
# each time, the order of shuffle will be the
# same each time
random.shuffle(sample_list, sample_function)
print("\nAfter the first shuffle : ")
print(sample_list)
 
sample_list = ['A', 'B', 'C', 'D', 'E']
 
random.shuffle(sample_list, sample_function)
print("\nAfter the second shuffle : ")
print(sample_list)

输出 ：

Original list : 
['A', 'B', 'C', 'D', 'E']

After the first shuffle : 
['A', 'D', 'B', 'E', 'C']

After the second shuffle : 
['A', 'D', 'B', 'E', 'C']