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I've written a little for loop, which is going to iterate over all of the elements in the list.
让我们先看看这儿的代码，我已经写了一个循环语句,用来迭代处理数组中所有的元素。
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All right, you can see that this little piece of code, it's got a loop in there, and what's it doing?
好，你们看到的这一小块代码,是做了一个循环吧？,他在做什么？
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You can kind of see where the syntax is going, looks like a loop, but you can kind of put blocks inside of you, and the little arrow suggests that once you get to the bottom just like our socks example, you're gonna do the following again.
从某种程度上你可以看到它的语法构成,像个循环，你也可以把，一些程序块放到循环中，如同短袜的例子，这个小箭头暗示你一旦到达底部,你将会重复接下来的事情。
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This is a highly simplified version, but sort of closes the loop on what we've been talking about.
以上是对整个过程的高度概括,但它涵盖了我们讲过的内容
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Once each time. Right? I only do one swap potentially, it-- though not one potentially, each time at the end of the loop I do a swap.
每次循环做一次，对么？我其实,就可能做了一次交换，也许并不是可能，每次循环的结束我都得做一次交换。
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Well I ought to be able to do that by simply generalizing the loop. And that's what the next piece of code on your a hand out shows you.
好的通过生成这个循环,我应该能够达到目的,这也是你们的讲义中下一段代码。
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The cookies were going back and forth and back and forth and the hearts up and down, well, this thing that we had that called a loop last week with a forever block with a statement inside of it is simply gonna look a little something like this.
这些饼干人来来回回的移动,还有这些爱心们上上下下地漂浮,都用到我们上周提到过的循环结构,当然还有个声明在里面，就有点像屏幕上,显示的这样。
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And I want to remind you, that block of code is a set of instructions, the same set of instructions that are going to be done each time through the loop.
我想提醒大家,这块代码是一个指令集,一个每次循环都会被执行的相同指令集,会变化的仅仅是变量的值。
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If I want a copy of the string, I've got to whip out my week 1 skills of just iterating with a four loop from left to right and make copies of those characters.
我需要那个字符串的一个拷贝，我使用,第一周的技巧，从左到右做四次迭代,然后复制这4个字符。
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So what I wanted to do is loop back, at least with a couple of things that we see recurring and very understandably so, but let's try to clear up a couple of frequently occurring issues.
所以我想要做的是回环，至少用两三个,我们看到的东西返回，并且可以理解地，让我们试着处理几个,频繁发生的事情。
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The loop invariant what does the loop invariant mean? It says, here is a property that is true of this structure every time through the loop.
循环不变量是什么意思？,它是一个在结构体中,每次循环都为真的属性。
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I can be a little more careful about keeping track of what goes on inside of that loop. If I don't have any more work to do, let me just stop.
我能更小心点来跟,踪循环里发生了什么,如果没什么可干的了，就停下来吧。
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Now I have the ability to create a loop, that is, to reuse the same pieces of code over and over again as I go around.
现在我们已经学会如何创建循环了，也就是，重复的一遍又一遍的,执行同一片代码。
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Then the next thing in the loop, we're going to enter a nested loop and say for every college in the list e, we're going to print the name of the college.
循环中的第二件事，是进入一个嵌套循环,这个嵌套循环将数组中的，大学名字显示出来。
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swap I'm going to keep track of a little variable called swap, it's initially true, and as long as it's true, I'm going to keep going, but inside of the loop I'm going to set it to false, and only if I do a swap will I set it to true.
我打算跟踪一个小的变量称为,初始值为真，只要它是真的,算法就会继续，但是在循环里,我打算把他设为假,除非交换发生，就把它设为真。
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They're running through a loop. It's a common way of thinking about problems.
有继承意义的迭代程序了,它们是以循环的模式来运行的。
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You could run through a little loop to say keep trying until you get one. But one of the ways I could deal with it is what's shown here.
你可以运行一个小循环来不断地做,直到得到一个输入,但你应该做的是弄明白这里到底要干什么。
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So with this type of loop, things get a little bit reversed.
这种类型的循环，东西变得有点颠倒的。
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All right. Second question: or maybe a better way of saying this, and the general format you're likely to see here is, a test involving a variable name, which must be initialized outside of the loop, and which interior to the loop gets changed, so that the test is going to change.
好，第二个问题：,换种更好的方式来说吧，你们通常喜欢的,方式是，这个测试涉及到一个变量名字，变量在循环外已经被初始化，然后循环内部会改变这个变量的值，因此测试结果会改变。
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God bless. Oh, sorry, that wasn't a sneeze, it was a two? How many swaps do I do in bubble sort? A lot. Right. Potentially a lot because I'm constantly doing that, that says I'm running that inner loop a whole bunch of times.
上帝保佑，哦，抱歉，我没说清楚，这是两个问题,在冒泡排序中要做多少次排序？许多，正确的,可能要做很多次，因为在持续的干,这就意味着它要做很多次内部循环。
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And remind you that inside of here, I'd better be changing the variable. All right, if that variable that's counting is not changing I'm going to be stuck in an infinite loop, so I ought to that, right, expect somewhere in there, a change of that variable. All right?
我最好改变了计数器的变量值，好，如果计数的变量没有变化的话，我就会被卡在一个无限循环里面,因此我应该【不可闻的声音】,对，在这里的某个地方，改变下计数器的变量，对不对？我要做的最后一件事情就是？
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Now this happens to be what we would call a linear process, because the number of times I go around the loop is directly related to the size of the argument. If I double 2 the argument, I'm going to double the number of times I go around the loop. If I increase it by five, 5 I'm going to increase by five the number of times I go around the loop.
这恰好是我们会成为,线性复杂度程序的一个例子,因为我要执行循环的次数是,和输入的参数的大小直接相关的,如果我将这个参数乘以,那么我就要将进行循环的次数也乘以2了，如果我把参数加上,那么循环的次数也要加上5了。
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One of the things we said last time was, with that set of things, the ability to give values-- sorry, to give names to values-- the ability to make decisions, the ability to loop as a function of that, the ability get things in and out, we said that that actually gave us a language we said was Turing-complete.
上次我们和以上内容一起说过，我们可以赋值--抱歉,为数值命名--可以做出判断决定-,并且据此进行循环,可以输入输出数据,我们说拥有这些功能的语言,是图灵完备的。
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is run a FOR loop here. I'm going to let the number of chickens be in this range.
我知道怎么做对吧？写一个小循环,我所需要做的就是运行一个for循环。
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At the end of the day, you can implement the exact same program using a while loop that you can using a for loop, it's just your code is going to look slightly different.
最终，你可以执行这个程序,再使用for循环的地方使用while循环，这只是使你的代码看起来稍微有点不同。
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So conceptually the key difference here, besides the syntax looking slightly different, it just means that if you want a chunk of code to execute no matter what initially, ; you can use the do while loop; if you want to check a condition first, you can use the while loop.
所以概念上，则关键的区别是，除了语法看起来有点不同，它的意思是如果你想要一段代码,最初无论如何都要执行，你就可以用do，while循环;,如果你想要先检查条件，你可以用while循环。
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You don't get the nice little feature of a for loop.
你没有理解for循环的美好的小特征。
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I can write it explicitly. I can write it inside of a FOR loop. And we've started to add, and we'll see a lot more of this, examples of collections of structures so that we don't just have to do something that can be easily described as walking through a set of things but can actually be a collection that you walk through.
我可以明确的写出来,我可以把它在FOR循环的内部写出来，然后我们开始学习了add这个运算符,我们会在以后学习很多的,集合的数据结构的例子,这样一来我们可以进行一些,很简单的遍历集合的操作,我想要为大家指出的最后一件事情是。
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