我和我的團隊（Python 新手）編寫了以下代碼來生成與特定城市和相關術語相關的 Spotify 歌曲。如果用戶輸入的城市不在我們的 CITY_KEY_WORDS 列表中，那么它會告訴用戶輸入將添加到請求文件中，然后將輸入寫入文件。代碼如下：from random import shufflefrom typing import Any, Dict, Listimport spotipyfrom spotipy.oauth2 import SpotifyClientCredentialssp = spotipy.Spotify( auth_manager=SpotifyClientCredentials(client_id="", client_secret=""))CITY_KEY_WORDS = { 'london': ['big ben', 'fuse'], 'paris': ['eiffel tower', 'notre dame', 'louvre'], 'manhattan': ['new york', 'new york city', 'nyc', 'empire state', 'wall street', ], 'rome': ['colosseum', 'roma', 'spanish steps', 'pantheon', 'sistine chapel', 'vatican'], 'berlin': ['berghain', 'berlin wall'],}def main(city: str, num_songs: int) -> List[Dict[str, Any]]: if city in CITY_KEY_WORDS: """Searches Spotify for songs that are about `city`. Returns at most `num_songs` tracks.""" results = [] # Search for songs that have `city` in the title results += sp.search(city, limit=50)['tracks']['items'] # 50 is the maximum Spotify's API allows # Search for songs that have key words associated with `city` if city.lower() in CITY_KEY_WORDS.keys(): for related_term in CITY_KEY_WORDS[city.lower()]: results += sp.search(related_term, limit=50)['tracks']['items'] # Shuffle the results so that they are not ordered by key word and return at most `num_songs` shuffle(results) return results[: num_songs]該代碼對于“if”語句運行良好（如果有人進入我們列出的城市）。但是，當運行 else 語句時，在操作正常執行后會出現 2 個錯誤（它將用戶的輸入打印并寫入文件）。出現的錯誤是：Traceback (most recent call last): File "...", line 48, in <module> display_tracks(tracks) File "...", line 41, in display_tracks for num, track in enumerate(tracks):TypeError: 'NoneType' object is not iterable請原諒我缺乏知識，但請有人幫忙解決這個問題嗎？我們還想在最后創建一個歌曲的播放列表，但在這方面遇到了困難。
2 回答
九州編程
TA貢獻1785條經驗 獲得超4個贊
您的函數在子句中main沒有語句，這會導致be 。迭代何時是導致錯誤的原因。您可以采取一些措施來改進代碼：returnelsetracksNonetracksNone
關注點分離：該
main函數正在做兩件不同的事情，檢查輸入和獲取曲目。一開始就做
.lower()一次，這樣就不必重復。遵循文檔約定。
使用前檢查響應
一些代碼清理
請參閱下面我上面建議的更改：
def fetch_tracks(city: str, num_songs: int) -> List[Dict[str, Any]]:
"""Searches Spotify for songs that are about `city`.
:param city: TODO: TBD
:param num_songs: TODO: TBD
:return: at most `num_songs` tracks.
"""
results = []
for search_term in [city, *CITY_KEY_WORDS[city]]:
response = sp.search(search_term, limit=50)
if response and 'tracks' in response and 'items' in response['tracks']:
results += response['tracks']['items']
# Shuffle the results so that they are not ordered by key word and return
# at most `num_songs`
shuffle(results)
return results[: num_songs]
def display_tracks(tracks: List[Dict[str, Any]]) -> None:
"""Prints the name, artist and URL of each track in `tracks`"""
for num, track in enumerate(tracks):
# Print the relevant details
print(
f"{num + 1}. {track['name']} - {track['artists'][0]['name']} "
f"{track['external_urls']['spotify']}")
def main():
city = input("Virtual holiday city? ")
city = city.lower()
# Check the input city and handle unsupported cities.
if city not in CITY_KEY_WORDS:
print("Unfortunately, this city is not yet in our system. "
"We will add it to our requests file.")
with open('requests.txt', 'a') as f:
f.write(f"{city}\n")
exit()
number_of_songs = input("How many songs would you like? ")
tracks = fetch_tracks(city, int(number_of_songs))
display_tracks(tracks)
if __name__ == '__main__':
main()
慕標琳琳
TA貢獻1830條經驗 獲得超9個贊
當if執行 - 語句時，您將返回一個項目列表并將它們輸入到display_tracks()函數中。else但是執行 - 語句時會發生什么？您將請求添加到文本文件中，但不返回任何內容（或項目NoneType）并將其輸入到display_tracks(). display_tracks然后迭代此NoneType-item，拋出異常。
您只想在確實有任何要顯示的曲目時顯示曲目。實現此目的的一種方法是將 的調用display_tracks()移至您的main函數中，但是如果沒有找到您的搜索項的曲目，則會引發相同的錯誤。另一個解決方案是首先檢查您的內容是否tracks不為空，或者使用類似的方法捕獲TypeError- 異常
tracks = main(city, int(number_of_songs))
try:
display_tracks(tracks)
except TypeError:
pass
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