我需要停止我的for循環，但休息不會工作

Question

我已經寫了一些代碼，可以找到用戶在一個句子中輸入的單詞的位置。但是，在他們輸入詞語後，我需要找到該位置的代碼並打印出來，然後停在那裏。但它不會停止，而是繼續到else語句，如果他們輸入不在句子中的單詞，會發生什麼情況。如果我使用break，它只會打印單詞的第一個位置，如果它在句子中出現多次。我該怎麼辦？

sentence = "ask not what your country can do for you ask what you can do for your country" 
print(sentence) 
keyword = input("Input a keyword from the sentence: ").lower() 
words = sentence.split(' ') 

for i, word in enumerate(words): 
    if keyword == word: 
     print("The position of %s in the sentence is %s" % (keyword,i+1)) 


if keyword != word: 
    keyword2 = input("That was an invalid input. Please enter a word that is in the sentence: ").lower() 
    words = sentence.split(' ') 
    for i, word in enumerate(words): 
     if keyword2 == word: 
      print("The position of %s is %s" % (keyword2,i+1)) 

Answer 1

您可以先獲取所有索引，然後只在沒有匹配索引時才執行第二個函數。

indexes = [i for i, word in enumerate(words) if word == keyword] 
if indexes: 
    for i in indexes: 
     print('The position is {}'.format(i)) 

if not indexes: 
    ... 

你也可以使用一個while循環，這樣就可以只使用一個單一的步驟。

keyword = input("Please enter a word that is in the sentence: ").lower() 
indexes = [i for i, word in enumerate(words) if word == keyword] 
while not indexes: 
    keyword = input("That was an invalid input. Please enter a word that is in the sentence: ").lower() 
    indexes = [i for i, word in enumerate(words) if word == keyword] 

for i in indexes: 
    print('The position is {}'.format(i))