Question

我的循环似乎迭代了第一个字母，然后打破了虽然它应该遍历secretWord中的每个字母，例如，下面的代码应该打印出“_pp_e”但是它只打印“_”。我不明白，那段代码有什么问题？

def getGuessedWord(secretWord, lettersGuessed):
    '''
    secretWord: string, the word the user is guessing
    lettersGuessed: list, what letters have been guessed so far
    returns: string, comprised of letters and underscores that represents
      what letters in secretWord have been guessed so far.
    '''
    # FILL IN YOUR CODE HERE...
    for letter in secretWord:
        if letter in lettersGuessed:
            return letter
        else:
            return '_'

print(getGuessedWord("apple",  ['e', 'i', 'k', 'p', 'r', 's']))

Answer 1

第一次迭代中来自函数的return。 return 结束一个函数，然后，for循环不会继续。

您需要在函数本身中建立返回值。通过使用列表首先保存所有字符然后将它们连接成一个字符串，最后一次构建一个字符的结果字符串：

def getGuessedWord(secretWord, lettersGuessed): ''' secretWord: string, the word the user is guessing lettersGuessed: list, what letters have been guessed so far returns: string, comprised of letters and underscores that represents what letters in secretWord have been guessed so far. ''' guessed = [] for letter in secretWord: if letter in lettersGuessed: guessed.append(letter) else: guessed.append('_') return ''.join(guessed)

如果您喜欢冒险，您甚至可以将其设为list comprehension，并在一行中完成所有工作：

def getGuessedWord(secretWord, lettersGuessed): ''' secretWord: string, the word the user is guessing lettersGuessed: list, what letters have been guessed so far returns: string, comprised of letters and underscores that represents what letters in secretWord have been guessed so far. ''' return ''.join([l if l in lettersGuessed else '_' for l in secretWord])

任一版本都会产生预期的输出：

>>> print(getGuessedWord("apple", ['e', 'i', 'k', 'p', 'r', 's'])) _pp_e

Answer 2

return关键字退出调用函数。这应该可以解决问题：

def getGuessedWord(secretWord, lettersGuessed):

    result = ''
    for letter in secretWord:
        if letter in lettersGuessed:
            result += letter
        else:
            result += '_'
    return result

print(getGuessedWord("apple",  ['e', 'i', 'k', 'p', 'r', 's']))

在这里，你以一个空字符串作为结果，并附加一个字母（如果它包含在列表中）或下划线（如果不是），然后返回结果字符串。

for循环只遍历第一个字母

2 个答案: