b OK. In this example I'd use b. All right, as b get-- b is the thing that's changing as I go along here, but it could be things like, how many elements are there in a list if the input is a list, could be how many digits are there in a string if the input's a string, it could be the size of the integer as we go along. All right.?

好，在这个例子里我会用，因为b是一直在变的东西,但是也可能是如下情况：,如果输入是数组的话,变化的就是数组的元素数，如果输入是字符串的话,变化的就是字符串的长度，如果是integer的话,可能就是这个数的大小，对不对？

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