为什么我的输入没有被附加到数组中？ （蟒蛇）

Question

这是我的代码：

example = "house"
example = example.upper()
guess = ''
array = []

def guess_function(guess):
    guess = input("Enter a letter:  ")
    guess = guess.upper()
    while ord(guess) < 64 or ord(guess) > 90:
        print("Invalid input, please try again..")
        guess = input("Enter a letter: ")
        guess = guess.upper()
    return guess

def populate_array(array):
    while len(array) < 26: #I have this condition so I can have every letter    in the alphabet
        guess_function(guess)
        array.append(guess)
        print(array)
        populate_array(array)
print(populate_array(array))

我希望这段代码可以将每个字母附加到空列表中。但由于某种原因，我得到了这个：['']，每次我输入一个新的输入时，它只会添加一组额外的''。我的代码出了什么问题？

Answer 1

您已分配＆＃39;猜测＆＃39;作为顶部的全局变量，但您需要添加全局猜测＆＃39;如果您打算在功能中访问它。就目前而言，您将其用作局部变量并返回，但从未将结果分配给可用于附加到数组的内容。

Answer 2

guess = input("Enter a letter:  ")

此分配不会将input(...)的输出分配给全局变量guess，而是分配给无法从外部访问的参数guess。

更好的版本是

example = "house".upper()
all_guesses = [] # Not used by me, but you'll use it

def get_guess():
    guess = input("Enter a letter:  ")
    guess = guess.upper()
    while ord(guess) < 64 or ord(guess) > 90:
        print("Invalid input, please try again..")
        guess = input("Enter a letter: ")
        guess = guess.upper()
    return guess

def populate_array():
    array = []
    while len(array) < 26:
        guess = get_guess()
        array.append(guess)
    return array
print(populate_array())

如果你不是真的，绝对需要，应该避免全球状态。 guess不必是全局的，因为它不会在get_guess

之外使用

Answer 3

您将空字符串guess = ''）传递给guess_function，而不将guess_function的返回值分配给变量。然后，您在数组中附加空字符串guess，而不是保存guess_function返回值的变量，这就是您的数组填充''的原因。

我已经对代码的清理工作版本添加了评论，描述了我的选择。

# Initializing a "guess" variable in global scope is unnecessary, because it's unused.
array = []

# This function doesn't need any arguments, because it handles all logic inside.
def guess_function():
    guess = input("Enter a letter:  ")
    guess = guess.upper()
    while ord(guess) < 64 or ord(guess) > 90:
        print("Invalid input, please try again..")
        guess = input("Enter a letter: ")
        guess = guess.upper()
    return guess

def populate_array(array):
    while len(array) < 26:
        # Call the function and assign to a variable the result.
        guess = guess_function()
        array.append(guess)
        # Because of the while loop, no need to recursively call the self-same function.
        # Instead of printing the array each time, return the array.
        # This way, the calling function can determine how to display the array.
    return array


print(populate_array(array))