python - 使用装饰器在 Python 中求解数学方程(Past Paper Qs)

Question

有人要求我求一个函数的模 37 (%37)。

Ensure that your function returns an integer between 0 and 36. Assume that all arguments are integers between 0 and 36. Write a decorator @normalize_37 that does just that. I.e. if 'bar' is a function, then the decorated function will have all its arguments reduced modulo 37 and its return value reduced modulo 37.

查找:

@normalize_37
def add(x,y):
     return x+y
print(add(45,67))
#where the answer is 1.

@normalize_37
 def bar(n):
     if n >= 37 or n <= -1:
         raise ValueError
     else:
         return n
print(bar(123))
#where the answer is 12

到目前为止，我是通过在线查找装饰器而初步想到的:

import math

def document(f):
    def wrap(x,y):
        print("I am going to find modulo 37 of", x,y)
        f(x,y)
    return wrap

@document
def add(x,y):
    print(add(x,y)%37)

add(45,67)

但它对我不起作用，当我运行它时，它只是一遍又一遍地重复“我要找到模 37”位。

Answer 1

请求的具体表格是

def normalize_37(fn):              # the decorator
    def inner(x, y):               # the new decorated function
        return fn(x, y) % 37
    return inner

@normalize_37
def add(x, y):
    return x + y

add(45, 67)    # returns 112 % 37 == 1

但我们可以进一步概括，

def normalize(n):                  # make a decorator!
    def decorator(fn):             # the decorator
        def inner(*args):          # the new decorated function
            return fn(*args) % n
        return inner
    return decorator

@normalize(37)
def add(*args):
    return sum(args)

add(45, 67)    # returns 112 % 37 == 1

编辑: 好吧，我也错过了关于减少参数的部分。于是就变成了

def normalize(n):                  # make a decorator!
    def decorator(fn):             # the decorator
        def inner(*args):          # the new decorated function
            return fn(*(arg % n for arg in args)) % n
        return inner
    return decorator

@normalize(37)
def add(*args):
    return sum(args)

add(45, 67)    # returns ((45 % 37) + (67 % 37)) % 37 == 1

或者更简单的形式，

def normalize_37(fn):              # the decorator
    def inner(x, y):               # the new decorated function
        return fn(x % 37, y % 37) % 37
    return inner