So the end result, because someone wrote this function years ago is that printf takes this thing, takes this thing, David plops David inside the middle of that formatted string and then renders the whole result.

基于这是某人多年以前写的程序,最终的结果是打印出这个，这个，在格式化字符串中间的,然后返回结果。

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It says, if I want to print out something I built in Cartesian form up here, says, again, I'm going to pass it in a pointer to the instance, that self thing, and then I'm going to return a string that I combine together with an open self and close paren, a comma in the middle, and getting the x-value and the y-value and converting them into strings before I put the whole thing together.

这不仅仅是个列表,它是怎么来做的？,流程是：如果我想要返回,一些已经在笛卡尔模式下建好的值，好，再说一遍，我首先要传入一个,指向实例的指针,也就是，然后我会返回一个,由开括号，闭括号,中间的一个逗号,以及提前转换为字符串格式的。

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