減少函數內變量的正確方法是什么？

Question

有沒有辦法讓這個工作，或者我必須找到一種不同的邏輯方式？ 作為我遇到的問題的一個例子，我寫得非常快。 每次猜測函數運行時，我想添加一個猜測。 問題是，當我退出函數然后重新進入時，猜測計數器重置為 0。而且我不能在定義的函數之外擁有變量“猜測”，這讓我感到困惑。

這樣做的正確方法是什么？

def guess():
    x = 5
    guesses = 0
    while guesses < 5:
        guess = input("Guess: ")
        if guess == x:
            print("You win")
        else:
            print("try again")
            guesses = guesses + 1
            movement()

def movement():
    choice = input("left or guess")
    if choice == "left":
        movement()
    if choice == "guess":
        guess()

movement()

我希望能夠離開函數並重新輸入而無需重置 guesses 變量。

Answer 1

處理此問題的常用方法是將您的信息封裝在類的實例中。 該實例將保存諸如猜測次數和您想要維護的任何其他狀態等屬性。 這些方法將創建包括操縱這些屬性的行為。

在這里您可以創建一個新實例，包括傳遞初始猜測次數和答案的選項：

class Guess:
    def __init__(self, answer = 2, guesses = 5): # 2 and 5 are deafaults if nothing is passed in
        self.guesses = guesses
        self.answer = answer

    def guess(self):
        guess = input("Guess: ")
        if guess == self.answer:
            print("you win")
        else:
            self.guesses -= 1
            print(f"You have {self.guesses} left")
            self.movement()

    def movement(self):
        choice = input("left or guess? ")
        if choice == "left":
            self.movement()
        if choice == "guess":
            self.guess()


g = Guess(answer = 5, guesses = 2) # make a new game using the passed in values 
g.movement() # start game

Answer 2

我喜歡 OOP（面向對象編程），所以我會選擇另一個答案。 話雖如此，如果您願意，Python 有一些對此有用的東西，稱為generator 。 把它想象成一個記住狀態的函數。

def my_gen():
    x = 0
    while True:
        # Yield acts just like a normal return, the functions stops
        # after returning x.
        yield x
        # Next time the generator is called it will resume
        # right here, add it will remember all the values
        # it previously had (i.e. it remembers the last value for x.
        x += 1
# Note a generator is called differently then a normal function
# then a normal function
g = my_gen()
print(next(g)) # prints 0
print(next(g)) # prints 1
print(next(g)) # prints 2

還包括發電機如何停止：

def my_gen2():
    x = 2
    while x > 0:
        yield x
        x -= 1
# Note that when a generator function
# has no more yields it will throw a
# StopIteration Exception
g = my_gen2()
print(next(g)) # prints 2
print(next(g)) # prints 1
print(next(g)) # This will cause an StopIteration Exception

# you can get around this either by:
g = my_gen2()
for x in g: # A for loop automatically stops on StopIteration
    print(x)

# Or catch the Exception
try:
    g = my_gen2()
    for _ in range(5): # Just calling next enough times for it to break
        print(next(g))
except StopIteration:
    print("can't call generator any more")

您的代碼：

def guess():
    x = 5
    guesses = 0
    num_tries = 1
    while guesses < num_tries:
        guess = input("Guess: ")
        if guess == x:
            print("You win")
            yield 0
        else:
            guesses += 1
        if guesses == num_tries:
            yield 0 # Game over
        else:
            print("Try again")
            yield 1 # Game can continue


# Don't add unneeded recusion.
# Python has a limited stack. Don't consume it
# for something you should do in a loop.
def play():
    g = guess()
    while True:
        choice = input("left or guess: ")
        print(choice)
        if choice == "left":
            continue
        elif choice == "guess":
            try:
                if not next(g):
                    print("Game over")
                    break
            except StopIteration:
                print("Somehow called to many times")
                break
        else:
            print("Invalid Entry")
play()

Answer 3

def guess(guesses = 0,x = 5):
    choice = input("left or guess")
    guesses = guesses + 1
    if choice == "left":
        return guess(guesses=guesses)
    elif choice == "guess":
        guessint  = int(input("Guess(int): "))
        if guessint  == x:
            print("You win")
            print('number:', guesses)
            return guesses
        else:
            print("try again")
            return guess(guesses=guesses)
guess()