## Generators - Design of Computer Programs

• 0:00 - 0:04
We saw generator expressions and functions in Unit 2,
• 0:04 - 0:07
but some people in the forums still seemed a bit confused.
• 0:07 - 0:09
Don't worry. This is understandable.
• 0:09 - 0:12
The generator is an entirely new object, and it can be confusing.
• 0:12 - 0:14
In the next few videos, we're going to answer three questions.
• 0:14 - 0:20
How do we use generators? I think this is actually an easier question to answer than the second.
• 0:20 - 0:25
What is a generator expression/function/object?
• 0:25 - 0:29
We'll also talk about when and why do we use generators?
• 0:29 - 0:32
• 0:32 - 0:37
We want to compute the sum of the squares of the integers from 1 to 1 million.
• 0:37 - 0:44
That would be 1 + 4 + 9--and I probably shouldn't write all of these out.
• 0:44 - 0:47
The question is how would you do this?
• 0:47 - 0:53
• 0:53 - 0:56
Maybe your function would have looked something like this
• 0:56 - 1:00
where we make an empty list, append all of the squares to that list,
• 1:00 - 1:02
and then return the sum of that list.
• 1:02 - 1:06
Then you would have called your function with an argument of 1 million,
• 1:06 - 1:09
• 1:09 - 1:15
First let me say this is a find solution. It gets the job done, but it has some problems.
• 1:15 - 1:20
Keeping in mind that we just want to make this calculation once,
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what do you think is the biggest problem with this solution.
• 1:23 - 1:26
Do you think it's messy, and it unnecessary clutters up the program?
• 1:26 - 1:29
Do you think it uses memory when it doesn't really have to?
• 1:29 - 1:33
Do you think it runs to slowly? Or do you think the code doesn't work?
• 1:33 - 1:36
You may have several problems with this, so it's somewhat subjective.
• 1:36 - 1:39
Just choose whatever you think is the biggest problem.
タイトル：
Generators - Design of Computer Programs

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Video Language:
English
Team:
Udacity
プロジェクト：
CS212 - Design of Computer Programs
Duration:
01:40
 Udacity Robot edited 英語(米国) subtitles for Generators - Design of Computer Programs Gundega edited 英語(米国) subtitles for Generators - Design of Computer Programs Amara Bot added a translation

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