我怎样才能使它不被0除？

Question

我正在尝试获得单词长度的平均值。 如何防止它出现零除错误？

def main():
    allwords = []
    while True:
        words = input("Enter a line of words, press Enter to stop: ")
        if not words:
            break
        allwords.extend(words.split())
    average = sum(len(words) for words in allwords) / len(allwords)
    print("There were {:.2f} words".format(len(allwords)))
    print("Average word length {:.2f}".format(average))    
main() 

Answer 1

仅当至少有一个词时， average才有意义； 当它为空时，您正在尝试计算0 / 0 ，这是行不通的。 因此，当allwords为空时，不要计算或显示average ：

def main():
    allwords = []
    while True:
        words = input("Enter a line of words, press Enter to stop: ")
        if not words:
            break
        allwords.extend(words.split())
    # Moved average computation lower so only one if needed
    print("There were {} words".format(len(allwords)))
    if allwords:  # Only run contents when you got at least one word
        average = sum(len(words) for words in allwords) / len(allwords)
        print("Average word length {:.2f}".format(average))    

if __name__ == '__main__':
    main() 

Answer 2

最简单的选择是在继续之前检查allwords是否包含某些内容：

def main():
    allwords = []
    while True:
        words = input("Enter a line of words, press Enter to stop: ").strip()
        if not words:
            break
        allwords.extend(words.split())
    print("There were {:.2f} words".format(len(allwords)))
    if allwords:
        average = sum(len(words) for words in allwords) / len(allwords)
        print("Average word length {:.2f}".format(average))
main()