我需要在python 3中用整数来表示无限。

Question

我用Python 3，Windows 10，PyCharm工作。

我正在构建一个小程序，让你输入你的年龄并返回 "Happy {age}{termination, eg: st, nd}!"。

问题是，我想以某种方式避免这样的情况，即你将你的年龄写成1041岁，然后它就会说 "第1041次快乐！"。所以我用了 list(range(21, 1001, 10)) 例如，终止符 "st"。然而，我希望能够使用 infinite 而不是1001。如果我用 math.inf我的代码中不接受这个浮点数。另外，我也不能把它转换为int。

我想用一个 n 比100还高的数字，并且有 list(range(21, n, 10))但我是个初学者，不知道怎么做，谢谢你的帮助。这是我的代码。

age = int(input('Type age: '))
if int(age) == 1:
    term = 'st'
elif int(age) == 2:
    term = 'nd'
elif int(age) == 3:
    term = 'rd'
elif int(age) in list(range(21, 1001, 10)):
    term = 'st'
elif int(age) in list(range(22, 1002, 10)):
    term = 'nd'
elif int(age) in list(range(23, 1003, 10)):
    term = 'rd'
else:
    term = 'th'
if int(age) >= 130:
    print("C'mon! you can't be THAT old, you geezer!\nStill, here you go:")
message = f"Happy {age}{term} birthday!"

print(message)

Answer 1

没有理由在一个庞大的系统中检查成员资格。list 这会占用大量的内存。你可以直接查看你的年龄 endswith.

age = input('Type age: ')
if age.endswith('11') or age.endswith('12') or age.endswith('13'):
    term = 'th'
elif age.endswith('1'):
    term = 'st'
elif age.endswith('2'):
    term = 'nd'
elif age.endswith('3'):
    term = 'rd'
else:
    term = 'th'

if int(age) >= 130:
    print("C'mon! you can't be THAT old, you geezer!\nStill, here you go:")
message = f"Happy {age}{term} birthday!"

print(message)

Answer 2

模数运算是解决这个问题的一个更好的（完全通用的）方法。

age = int(input('Type age: '))
if 11 <= (age % 100) <= 13:
    term = 'th'
elif age % 10 == 1:
    term = 'st'
elif age % 10 == 2:
    term = 'nd'
elif age % 10 == 3:
    term = 'rd'
else:
    term = 'th'
if age >= 130:
    print("C'mon! you can't be THAT old, you geezer!\nStill, here you go:")
message = f"Happy {age}{term} birthday!"

print(message)

Answer 3

你不需要把它改成list, 如果你把它改成list，可能会出错. 你只要输入 age in range(s, e, i). 如果你想要更高的，比如无穷大，就用这样的方法。age in range(21, sys.maxsize**100, 10)

import sys
inf = sys.maxsize**10
age = int(input('Type age: '))
if int(age) == 1: term = 'st'
elif int(age) == 2: term = 'nd'
elif int(age) == 3: term = "rd"
elif int(age) in range(21, inf, 10): term = 'st'
elif int(age) in range(22, inf, 10): term = "nd"
elif int(age) in range(23, inf, 10): term = 'rd'
else: term = 'th'

if int(age) >= 130:
    print("C'mon! you can't be THAT old, you geezer!\nStill, here you go:")
message = f"Happy {age}{term} birthday!"
print(message)

但是，你为什么要使用 range 如果有比它更容易？就像让它成为 string 然后检查最后一个数字。

age = int(input("Type age: "))
term = ["st", "nd", "rd", "th"][3 if age%10 > 3 or age%100 in range(10, 20) else age%10-1]
if age > 130: message = "blah-blah-blah"
print(message)

是的，我知道结果是不同的。但是，接下来我给你看的代码也可以处理高于百的数字。比如101，在你的代码中会是第101次，我想这是不对的。变量 term 我有投入 ternary operator 或 conditional expression.在Python中 [if_true] if [condition] else [if_false]在JS中 condition? if_true:if_false

在Python中从1到无限循环