英文:
strange behavior with randint in python
问题
这段代码有时会出现以下输出：
value 1rol don't exist
为什么会出现这种行为以及存在哪些替代方法？
这种行为发生的原因是因为 rol_rand() 函数在每次调用时都会生成一个新的随机数，然后与 rol_dict 中的值进行比较。在两次调用 rol_rand() 之间，可能会生成不同的随机数，因此可能会导致不同的结果。
为了获得一致的结果，您可以在单个函数调用中生成随机数，并将其与 rol_dict 中的值进行比较，然后打印相应的结果。这样可以确保在同一次函数调用中进行比较，而不会出现不一致的结果。
以下是修复后的代码：
rol_dict = {0: "value 1", 1: "value 2", 2: "value 3"}from random import randint # 导入随机数生成函数def rol_rand():return rol_dict.get(randint(0, 2))result = rol_rand()if result == rol_dict.get(0):print("value 1")elif result == rol_dict.get(1):print("value 2")elif result == rol_dict.get(2):print("value 3")else:print(result)print("rol don't exist")
这样，您可以确保随机数只在 rol_rand() 函数的单次调用中生成，从而获得一致的结果。
英文:
rol_dict = { 0: "value 1", 1: "value 2", 2: "value 3" }def rol_rand():global rol_listreturn rol_dict.get(randint(0, 2))rol_rand()if rol_rand() == rol_dict.get(0):print("value 1")elif rol_rand() == rol_dict.get(1):print("value 2")elif rol_rand() == rol_dict.get(2):print("value 3")else:print(rol_rand())print("rol don't exist")
For this code some times appear this output
value 1rol don't exist
why???
Why does this behavior occur and what alternatives exist?
答案1
得分: 1
问题在于你实际上调用了 rol_rand 多次，由于它每次返回一个随机数，因此不能保证一致性。
你的当前程序获取一个介于0和2之间的随机数。如果不是0，它会投掷一个新的随机数，然后检查它是否为1。如果不是，它会再次获取一个新的随机数并检查它是否为2。很可能你会得到3个与它们的检查不相对应的值。
为了解决这个问题，你只需要将投掷结果存储在一个变量中，像这样：
from random import randintrol_dict = { 0: "值 1", 1: "值 2", 2: "值 3" }def rol_rand():return rol_dict.get(randint(0, 2))saved_roll = rol_rand()if saved_roll == rol_dict.get(0):print("值 1")elif saved_roll == rol_dict.get(1):print("值 2")elif saved_roll == rol_dict.get(2):print("值 3")else:print(saved_roll)print("投掷结果不存在")
英文:
The issue lies with the fact that you actually call rol_rand multiple different times, and since it returns a random number every time, there is not guaranteed consistency.
Your current program gets a random number between 0 and 2. If it's not 0, it rolls a new random number, checks if its 1. If not it gets a new random number again and checks if its 2. It's somewhat likely that you get 3 values that don't correspond to their checks.
In order to fix this, you just need to store the roll in a variable like so
from random import randintrol_dict = { 0: "value 1", 1: "value 2", 2: "value 3" }def rol_rand():return rol_dict.get(randint(0, 2))saved_roll = rol_rand()if saved_roll == rol_dict.get(0):print("value 1")elif saved_roll == rol_dict.get(1):print("value 2")elif saved_roll == rol_dict.get(2):print("value 3")else:print(saved_roll)print("rol don't exist")
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