只能将 str （而非列表）连接到 str

Question

我不断收到“只能将 str （不是列表）连接到 str”，但我不确定为什么会收到此错误。我对 python 相当陌生，所以任何帮助将不胜感激。def oldMacdonald():    return "Old MacDonald had a farm, Ee-igh, Ee-igh, Oh!\n"def verseFor(animal, sound):    lyrics = oldMacdonald() + "And on his farm he had a " + animal + ", Ee-igh, Ee-igh, Oh!\n" \        "With a " + sound + ", " + sound + " here and a " + sound + ", " \        "" + sound + ".\nHere a " + sound + ", there a " + sound + ", " \        "everywhere a " + sound + ", " + sound + "\n" + oldMacdonald()    return lyricsdef main():    sound = ["moo", "oink", "neigh", "cluck", "bahh"]    for animal in ["cow", "pig", "horse", "chick", "sheep"]:        print(verseFor(animal, sound))main()

Answer 1

    所以基本上，在这段代码中

sound = ["moo", "oink", "neigh", "cluck", "bahh"]

    for animal in ["cow", "pig", "horse", "chick", "sheep"]:

        print(verseFor(animal, sound))

sound是一个列表并且animal正在迭代列表，即动物是列表的单个元素，意味着cow在第一次迭代、pig第二次、horse第三次等等。

但是您sound在 中传递的是整个列表，而不是其中的单个元素verseFor。

因此，您必须迭代两个列表，以逐个元素发送它们的动物和声音。如前所述，您可以zip像这样使用。

sound = ["moo", "oink", "neigh", "cluck", "bahh"]

animal = ["cow", "pig", "horse", "chick", "sheep"]

for ani, sou in zip(animal, sound):

    print(verseFor(ani, sou))

现在您正在循环播放声音和动物元素。如果你查看 的输出zip，你会得到这个。

list(zip(animal,sound))

>>>[('cow', 'moo'),

 ('pig', 'oink'),

 ('horse', 'neigh'),

 ('chick', 'cluck'),

 ('sheep', 'bahh')]

所以基本上在我提供的代码的第一次迭代中，我们传入cow和。然后在下一次迭代中分别进行和，依此类推。animoosoupigoink

Answer 2

使用邮编

animals = ["cow", "pig", "horse", "chick", "sheep"]

sounds = ["moo", "oink", "neigh", "cluck", "bahh"]

for animal, sound in zip(animals, sounds):

  print(verseFor(animal, sound))

Answer 3

def main():

    sound = ["moo", "oink", "neigh", "cluck", "bahh"]

    for animal in ["cow", "pig", "horse", "chick", "sheep"]:

        print(verseFor(animal, sound))

问题出在声音字典上。这是一个快速修复：

def main():

    animals = [ ["cow", "moo"], ["pig", "neigh"], ["sheep", "bahh"] ]

    for animal in animals:

        print(verseFor(animal[0], animal[1]))

或者你可以使用这个方法：

def main():

    animals = [

        {

            "name" : "cow",

            "sound": "moe"

        },

        {

            "name" : "pig",

            "sound": "haha"

        },

        {

            "name" : "dog",

            "sound": "lol"

        }

    ]

    for animal in animals:

        print(verseFor(animal["name"], animal["sound"))

Answer 4

您必须将字符串连接到字符串。因此，要实现您想要做的事情，您必须像这样重写它：

lyrics = oldMacdonald() + "And on his farm he had a " + animal + ", Ee-igh, Ee-igh, Oh!\n" \

        "With a " + sound[0] + ", " + sound[1] + " here and a " + sound[2] + ", " \

        "" + sound[3] + ".\nHere a " + sound[4] + ", there a " + sound[5] + ", " \

        "everywhere a " + sound[6] + ", " + sound[7] + "\n" + oldMacdonald()

但是，还有一个额外的问题：您只有 5 种动物及其 5 个相应的声音，但您在歌词中放置了 8 个声音......！所以我们在歌词上添加了至少 3 个额外的“声音”。您可能想查看网络上优秀的 Python 教程之一，例如官方 Python 网站https://docs.python.org/3/tutorial/中的教程

Answer 5

实际问题的答案是您需要使用 一起迭代两个列表zip。

然而，单独来看，它打印出“a oink”令我烦恼。这是一个将打印“an oink”的版本——该a函数返回一个前面带有适当的不定冠词（“a”或“an”）的单词。

def oldMacdonald():

    return "Old MacDonald had a farm, Ee-igh, Ee-igh, Oh!"

def a(thing):

    if thing[0] in 'aeiou':

        return f'an {thing}'

    else:

        return f'a {thing}'

def verseFor(animal, sound):

    an_animal = a(animal)

    a_sound = a(sound)

    lyrics = f"""{oldMacdonald()}

And on his farm he had {an_animal}, Ee-igh, Ee-igh, Oh!

With {a_sound}, {sound} here and {a_sound}, {sound} there.

Here {a_sound}, there {a_sound}, everywhere {a_sound}, {sound}.

{oldMacdonald()}

"""

    return lyrics

def main():

    sounds = ["moo", "oink", "neigh", "cluck", "bahh"]

    animals = ["cow", "pig", "horse", "chick", "sheep"]

    for animal, sound in zip(animals, sounds):

        print(verseFor(animal, sound))

main()

Answer 6

你可以用这个...

def oldMacdonald():

    return "Old MacDonald had a farm, Ee-igh, Ee-igh, Oh!\n"

def verseFor(animal, sound):

    lyrics = oldMacdonald() + "And on his farm he had a " + animal + ", Ee-igh, Ee-igh, Oh!\n" \

                                                                        "With a " + sound + ", " + sound + " here and a " + sound + ", " \

                                                                                                                                             "" + sound + ".\nHere a " + sound + ", there a " + sound + ", " \

                                                                                                                                                                                                                 "everywhere a " + sound + ", " + sound + "\n" + oldMacdonald()

    return lyrics

def main():

    for animal,sound in zip(["cow", "pig", "horse", "chick", "sheep"],["moo", "oink", "neigh", "cluck", "bahh"]):

        print(verseFor(animal, sound))

main()