5. Tuples, Lists, Aliasing, Mutability, and Cloning 

pre labeling ​​0:01:27 Content of Lecture05 0:02:32​ New data type : Tuple 0:04:04 tuple slicing 0:05:35 tuple swapping 0:08:00 0:09:09 Manipulating tuples 0:13:00 ​0:12:00 ​0:15:31​ New data type : List 0:16:00 0:18:00 0:19:43 Operation on list 0:20:00 ​0:22:00 0:23:15 Operation on list ​0:26:55 convert list to string and back 0:28:00​ 0:29:16 Operation on list 0:31:52 ​An analogy 0:34:04 idea of Aliasing ​ 0:36:54 Idea of Mutate ​0:38:45​ Nested List 0:40:17 Mutation and iteration try this python tour

*My takeaways:* 1. Introduce compound data type 1:05: tuple and list. 2. String of a sequence of character data, tuple is a sequence of data in any type 1:35 and is immutable meaning that we cannot change it once we created it. 3. Why we want to use tuple 5:20. 4. List is a sequence of data in any type 14:55 and it mutable. 5. Aliases 34:00. 6. Cloning 35:15. 7. Sorting lists .sort() vs sorted() 36:30.

The person that edited this video did not do as well as the other, previous lectures. When she is literally pointing at the board, the person kept showing us video of Ana, as she is directing attention away from her to the slides... And then didn't show the slides after she was done talking. The other videos were all done really well by contrast.

Thank you MIT for providing such invaluable content to the public! Thank you!

Python Tutor is such a good idea, it really helps show the concepts, well worth trying.

Great tutor and lessons however I would like a picture in picture of her and to be able to see what she is pointing at on the screen. hard to follow when you cannot see what she is pointing at.

Dr Ana Bell is absolutely phenomenal at what she does. What an amazing explanation again. I can't believe MIT has such high quality content up there available for free.

Thank you MIT , I am a non-IT student and understood everything.You are doing a great Job!! So far completed 2 courses taught by MIT online learned Alot ;)

Thank you, Dr. Ana for making OOPs and Inheritance so simple. I could not get concept at first when i was going through MIT 6.00. But now i am equipped with the understanding and assignment problem(6.00) is "walk in the park ". Thank You. May Cosmos bless you with more knowledge...

Good lectures , clear slides and Dr. Ana Bell very , very good professor . Tanks MIT to give us thats extraordinarys open courses .

camera could really focus on the slides a lot more

great video. python, while it's syntax is simple, that simplicity in some ways serves to detract from what is actually happening and how things are processed. It's more apparent when you compare python operations to something like that of c++, where you realize how much python does for you. Other than information hiding, it's a lovely language.

Thanks for the video. It really helps me to fully understand the difference between a tuple and a list.

thank you ,mit

Thank you, Dr. Ana for making this so simple. I could not get concept at first when i was going through MIT 6.00. But now i am equipped with the understanding and assignment problem(6.00) is "walk in the park ". Thank You. May Cosmos bless you with more knowledge...

Very helpful video indeed. Please show the slide always. Preferably, the slide and the professor together, maybe as picture in picture.

Ana explains all the theory very clear. Already knew most of the python she explains but it still helped me understand the big picture of programming

I like this lectures. High level of education. Thanks :)

This prof is amazing!

When she's talking about the contents on the projector screen, can you show more of the screen?

So much concept in this lecture.

camera needs to focus more on the board so we can see what she's talking about rather than just seeing her without the content. It's annoying sometimes

Darn, a lot of this information would have been great to do the hangman assignment! I did it all with strings and it was a bit challenging and probably hard for another programmer to follow in some areas. Lists are awesome.

I'll make a comment on it, since for some reason this really confused me: why .sort() returns none. (If I get something wrong, feel free to correct me and I will edit this comment, I am new to coding.) The reason that list.sort() and list.reverse() return None, while sorted(list) returns a list's values, is basically that the methods are completed by different means. Code that returns None is completed "in-place," which means that the original variable itself is not duplicated, only changed. Python does not want you to think that a new variable has been/could be created after running the method .sort() or .reverse() (or any other in-place method), and so it returns None. It is basically telling you that any method that is done in-place CANNOT generate a new variable because it has not duplicated the old variable. Meanwhile, sorted(list) is creating a new list entirely, and so you can assign it to a new variable name. ( sortedList = sorted(originalList) ) So basically, don't assign in-place methods to any new variables.

Wonderful! learned a lot! (It would be great if the camera man focused on the slides when Dr.Bell was pointing at them.)

Thank you professor Bell

I love that you put these lectures out for everyone to see. But wouldnt it be better to be able to see what the professor is pointing at on the slides? Makes it hard to understand what she is talking about when you can't see what she is referring to.

on the last problem you can search l2 instead of l1 as shown below: def k(l1,l2): for n in l2: While( n in l1): l1.remove(n)

Very informative

I ( we ) need a course from u just to define all these different words you use in most of ur analysis? ???

I have two questions: 1. How do I create a tuple, e.g. ((1, a) (2, b) (3, c)), without manually inputting values? 2. I can't figure out how to return an updated list from a function. Every time said function takes in a new input, all old values of local variables are forgotten and a new list is returned instead of an updated one. These questions are in regard to problem sheet 2 - Hangman. Any advice would be greatly appreciated!

I really love her subtle humor.

great lecture. Was just wondering, which software do you use to create the lecture slides?

Thank You very much!

The camera focus screwed up the whole thing but even though the doctor is good at teaching.

Comparing the current course available on edx and this, I still prefer the full lecture length videos from Fall '16. It's a lot more compact but it's easier to stay focused.

29:25 sort list and reverse list

no idea what is going on when using laser pointer to point at the physical screen where couldn't see in this video.

In that last example, couldn't one iterate through the list backwards?

5:28 what are they useful for

Loved the Photo of Justin Bieber being credited to © Justin Bieber in the end 😂

22:00 .extend, concatenate, delete, remove, etc...

I am curious as to the advantage of using a tuple over a list. It seems as though lists have the exact same functionality as tuples but with the added advantage of you being able to modify them(mutability) if you so choose to. Why not just alway use lists?

What does that \ do after max year?

Thanks for this! Mutable side effects are annoying! x_x

Thank you mit open course to provide us wonderful lectures . 🇺🇸 ❤ 🇮🇳

0:45 recap functions

What is the difference between the extend and append functions?

Thanks

i wish i could see the slide

lol ...when she says she's being modest about Justin

at 19:19 a list was not created yet. Can someone explain how this works

15:00 inmutable and mutable

What is the difference between append and extend of the list.

2:37 how to represent a tuple

For the last L1, L2 question, I've tried it with the first code but got L1 = [2, 3]. Is that because Python has been updated to fix that issue??

Bad editing. Makes watching this otherwise wonderful lecture a grind.

13:25 Who is Joe

i have no problem with the camera focus. I think it is great to point to the speaker for her great presentation skill. A good skill to learn for me.

I thought python runs from up to down. Your lists mutability shows down to up.

very helpful Could you share the code link and the PPT slide for such kind of code?

I have a confusion, If tuples are immutable how does nums = nums + (t[0],) work?

1:40 tuples

It would be better if the Slide and the lecturer are split in a video

I found something wrong which q=0 is right but the r = 4 is not true .

Obli is getting progress

👍👍👍👍👍

That's the only thing I don't like about these videos...when the professor is calling attention to something on the board the camera person just keeps staring at the professor. Can we see what's she's referring to? It's kinda frustrating.

so Python knows to map min_n and max_n to min_year and max_year....?

10:43

12:38

MIT need some camera training

Mam is very beautiful

Sadly we never see where she is pointing to, makes it a bit more difficult to follow, showing her waiving her arm is useless. Hope the latest videos produced by MIT fix this (if any), maybe some bright spark can solve it or solved it. And give her some rubber bands to keep her shirt sleeves up ?

Regarding: 39:56 Two lists, remove same value - Mutation and Iteration. Just thought I would share what I did: def remove_dups(L1, L2): L1_copy = L1[:] # Make a copy of L1 first, or iteration gets messed up. for e in L1_copy: if e in L2: L1.remove(e) print("iteration:", e, "list:", L1) # Prints each iteration number, along with the list. L1 = [1, 2, 3, 4] L2 = [1, 2, 5, 6] remove_dups(L1, L2) #--------------------------------------------------- print("", "-" * 30, "") # Puts a space/line/space between the two outputs. def remove_dups(L1, L2): for e in L1: if e in L2: L1.remove(e) print("iteration:", e, "list:", L1) # Prints each iteration number, along with the list. L1 = [1, 2, 3, 4] L2 = [1, 2, 5, 6] remove_dups(L1, L2) #------------------------------------------------------------------------------------------- ''' Output (you can see where it skips the second iteration): iteration: 1 list: [2, 3, 4] iteration: 2 list: [3, 4] iteration: 3 list: [3, 4] iteration: 4 list: [3, 4] - iteration: 1 list: [2, 3, 4] iteration: 3 list: [2, 3, 4] iteration: 4 list: [2, 3, 4] '''

The lecture is great, but the camera man should be fired. 10:47 Show us what professor is pointing at!!! OMG!

Functions and methods are same, isn't it?........

So, if you make a variable, equal to another variable, you are creating an alias. So, if var1 = var2, then var1 points to the same memory address as var2, making it a pointer to var2. Coming from c++ it seems weird that when assigning var1 to var2, it makes a pointer, instead of a copy. And instead, having to specify when do you want a copy... But it's ok, as python's thing is being syntactically simple and it also reduces the garbage to collect, etc, etc.

Ah yes, when a concept is being explained the logical course of action is to quickly cut away from the slides.

And this is why university is better than random youtube videos.

FYI don’t use capital “L” as a name, or capital L for anything in python code, it’s not idiomatic python, use a more descriptive name, and avoid capital letters, especially single capital letters. I understand why they did it though, for an example you don’t need a long name and lowercase “l” is hard to discern from the number 1 with a lot of fonts. Get yourself a monospaced programming font like Hack to help!

I feel like she didn't explain aliasing, mutability or cloning clearly.

Why Dr.Bell always wears the same clothes every-course?

this video introduced Justin Bieber to me

So why would I pay a ton of money for this?

Camera man is an BIG L

Bad way to learn programming...