Python 嵌套用于扩展现有列表的循环

给我解释一下这个代码。这是一个以字母形式将整数输入输出的程序。如果我输入35，那么输出将是35。我了解其中的大部分内容，但想知道如何从tens中获取值

twenty thirty forty fifty sixty seventy eighty ninety

代码是：

num = int(input("Enter the number:"))
numbers = ("zero one two three four five six seven eight nine".split())
numbers.extend("ten eleven twelve thirteen fourteen fifteen sixteen".split())
numbers.extend("seventeen eighteen nineteen".split())
numbers.extend(tens if ones == "zero" else (tens + " " + ones) 
    for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split()
    for ones in numbers[0:10])

print(numbers[num])

---

您在最后一行中看到的两个主要概念是和。看一看

为了更好地理解正在发生的事情，我们将把这条线分成更简单的部分：

TENS

for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split():
    print(tens)

numbers = ("zero one two three four five six seven eight nine".split())
for ones in numbers[0:10]:
    print(ones)

产出：二三四五六七八九

前面的for循环对应于以下列表：

(tens for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split())

    (ones for ones in numbers[0:10])

(tens if ones == "zero" else (tens + " " + ones) for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split() for ones in numbers[0:10])

如果不使用

打印

，则返回一个生成器。如果要查看结果，请执行以下操作：

print(list(tens for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split()))

一个

for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split():
    print(tens)

numbers = ("zero one two three four five six seven eight nine".split())
for ones in numbers[0:10]:
    print(ones)

输出：零一二三四五六七八九

前面的for循环对应于以下列表：

(tens for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split())

    (ones for ones in numbers[0:10])

(tens if ones == "zero" else (tens + " " + ones) for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split() for ones in numbers[0:10])

循环合并

for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split():
    print(tens)

numbers = ("zero one two three four five six seven eight nine".split())
for ones in numbers[0:10]:
    print(ones)

我们可以合并它们：

for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split():
    for ones in numbers[0:10]:
        print(tens + " " + ones)
OUTPUT: twenty zero
twenty one
twenty two
twenty three
twenty four
twenty five
twenty six
twenty seven
twenty eight
twenty nine
thirty zero
thirty one
thirty two
[...]

由于我们不太喜欢

twentzero

，我们将添加一个子句：

for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split():
    for ones in numbers[0:10]:
        if ones == "zero":
            print(tens)
        else:
            print(tens + " " + ones)
OUTPUT:
twenty
twenty one
twenty two
twenty three
twenty four
[...]

这与列表理解的行为相同：

(tens for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split())

    (ones for ones in numbers[0:10])

(tens if ones == "zero" else (tens + " " + ones) for tens in "twenty thirty forty fifty sixty seventy eighty ninety".split() for ones in numbers[0:10])

它返回一个列表（*），该列表将扩展到您的

数字列表。

最后，您输入的与列表中单词索引相对应的数字运行正常，没有问题。但是我想知道代码中的“十”是如何从“二十三四十五十六十七十八十九十”中取值的。假设我输入34，那么tens如何从“230405060708090”中得到“30D”@khelwood刚刚对代码进行了c&p处理，它按照预期运行，没有任何更改。你认为这有什么不对？“你说得对。我看错了，非常感谢