为什么我的if语句没有比较列表项

Question

    alphabet =["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
def decoder(input):
    inputlist = list(input)
    inputlength = len(input)
    alphabetlength = len(alphabet)
    result = "Decoded Sentence: "
    for x in range(inputlength):
        for y in range(alphabetlength):
            if inputlist[x] is alphabet[y]:
                print ("hi")
                if y == 24:
                    result += "a"
                if y == 25:
                    result += "b"
                else:
                    result += alphabet[y+2]
            if inputlist[x] is "(":
                result += "("
            if inputlist[x] is ")":
                result += ")"
            if inputlist[x] is ".":
                result += "."
            if inputlist[x] is " ":
                result += " "
    return result

我的代码应该增加一个句子的字母表2. ex:a-> c,l-> n我把print("hi")语句检查if语句是否曾被评估为真但它从来没有.有人可以告诉我为什么吗？

Answer 1

is检查对象标识.由于您似乎正在测试两个字符串是否具有相同的值(不是同一个对象),因此您可以更好地服务==.例如:

if inputlist[x] == alphabet[y]

您也可以为其他if语句进行相同的更新.