Lecture 53: Python has for loop and Iterables

Nafees AI Lab

An iterable in Python is an object capable of returning its members one at a time, permitting it to be iterated over in a for-loop. It represents a sequence of elements that can be traversed. Common examples of iterables include lists, tuples, strings, dictionaries, and sets.

Transcript

00:00Now, we have to learn about the for loop.

00:02For loop to which way to use.

00:04However, many of these courses and instructors

00:08have to start with the for loop.

00:10But I want to show you what the concept is basically.

00:16For loop, you can use your coding career.

00:20So, I think it is definitely very important

00:24that you should know what the mechanism is.

00:28So let's imagine, I'll give you an example, you have a new shop, okay?

00:33And the shop's special thing is that you have some items in which you have some apples, bananas, fruits, eggs and milk.

00:41Like apple, banana, cherry, egg milk.

00:43This is your new shop, okay?

00:45So I'll explain my list.

00:47Now, my question is that you have all the items in your shop, which is my list,

00:55this is the price tag.

00:57String concatenation, plus price tag, apple price tag, banana price tag,

01:04and this is the price tag.

01:07So how do you do it?

01:09Now, we have to do my list,

01:13and say index zero plus,

01:16this is the price tag,

01:20price tag,

01:24right?

01:25Yag, not tag.

01:26As you can see, my English is very fast.

01:28Okay?

01:29And now print it.

01:30Now, what do we do?

01:31Now, we will do this.

01:33Look at this.

01:34I will execute it.

01:35And I will do the first element to your apple price tag.

01:37Okay?

01:38Now, if you want to do it, how do we do it?

01:39So you can do it.

01:40Now, let's do it.

01:41Let's do it.

01:42Let's do it.

01:43Let's do it.

01:44Let's do it.

01:45Let's do it.

01:46Let's do it.

01:47Let's do it.

01:48Now, let's do it.

01:49Let's do it.

01:50Let's do it.

01:51Let's do it.

01:52Let's do it.

01:53Make sense.

01:54Okay?

01:55Okay?

01:56So, you have to price tag all the items.

01:58Now, my question is to you.

02:01Is it an easy way to do it?

02:04Imagine that you have 100,000 items.

02:07100,000.

02:08And I am not joking.

02:09Literally.

02:10100,000.

02:11Then what do we do?

02:12Then we will do it?

02:13Of course, not.

02:14So, you need a robust way to do it.

02:16Which can automatically return these items.

02:20This is the example of how you like that you need.

02:22One servant, one helper,

02:24one who gives you a item and gives you a price tag.

02:28And it will be a price tag.

02:34However,

02:35that the item,

02:37which you have to repair each item,

02:39you need to serve your fellow,

02:40the servant,

02:42which you have to do in the shop,

02:44all those items,

02:46to return all this items,

02:48You need to keep an arrangement in order to be returned.

02:50That's it.

02:52If an item is in such a configuration,

02:56you can return to be returned.

02:58That's it.

03:00If an item is in single condition,

03:02if an item is in container,

03:04you can return to be returned.

03:06This means that

03:08the item by itself

03:10to be returned,

03:12it needs to be specific characteristics.

03:16It needs to be inherent capability,

03:20which you want to build a list of together,

03:22which is one by one return

03:25to be returned.

03:26For example,

03:28the people will be returned to be returned.

03:30It is not that people will be returned to be returned.

03:32The people will be returned to be returned to be returned to be returned.

03:34This is why I have said this.

03:36Basically,

03:40when I tell you that

03:42the last thing is,

03:44the fact that the thing is,

03:46This is an easy way to do that if I call next function in my list and print it, then I need the first element to give me the first element.

04:04Now I can put a simple price tag on this.

04:08However, this is a problem.

04:10This is not iterator.

04:18This is not iterator.

04:20Basically, this is not iterator.

04:24However, the problem is that my list is iterator.

04:30My list is not iterator.

04:33My list is inherent capability.

04:36It is iterator.

04:40It is iterator.

04:42It is iterator.

04:44It is iterator.

04:46It is iterator.

04:50It is iterator.

04:52It is iterator.

04:54It is iterator.

04:56It is iterator.

05:06It is iterator цar-

05:08It is iterator.

05:09I will call the iterator and call the value of the new list.

05:17Now my new list is a iterator.

05:21Now I can call the next function.

05:24It is simple enough.

05:26I will execute the price tag.

05:29Now you can see the first solution.

05:32The number of items is more than the number of items.

05:38So the number of items can be fixed.

05:41But with this reason it will be simple.

05:43We need the next call to place

05:45and have well done.

05:48Excellent!

05:50Or maybe not.

05:54So how do I do it?

05:56I have done it.

05:58Then add and add.

06:01It will be milk price tag.

06:04However,

06:05which I will do next because milk is the last item and I will execute so it will give me a error and break it down

06:13Interesting

06:15What kind of method is that it can be more robust and versatile?

06:23Automatic error handling which can be given to the object in the iterator

06:30Then I will put the next function on it

06:33What can I do?

06:34Automatically

06:35And I will not write so long code

06:38So the answer is for loop

06:41For loop basically is what I have done

06:46Now look

06:47For loop define for for

06:50And you can write a variable in which you can store a value

06:54This is a new list

06:57Okay?

06:58So you can write value

06:59You can write my list

07:01And you can convert it

07:03And you can convert individual elements

07:05And you can assign the new list

07:08Okay?

07:09So I will say for new list in my list

07:12Make sense?

07:14So now this is the iterator

07:15So this is the first element

07:17New list

07:19And you can close it

07:20And you can close it

07:22Very simple right?

07:25If you wanna use the code

07:28Then you can run

07:30You can write the block

07:34Basically

07:37You can write a block

07:39I will write a block

07:40How to print it

07:41She will say

07:42If you have a new list

07:43If you have a new list

07:44You will write a price tag

07:45These are the old name

07:47Then

07:48Is the price tag

07:49Ctrl C

07:50Plus price tag

07:52That's it.

07:54I will execute it.

07:56Kaboom, the result is the same.

07:58But it is important enough,

08:00that the next error was given,

08:02it was given.

08:04Now, I will do one thing.

08:06I will beautify it.

08:08I will do X and multiply by 20.

08:10Run.

08:12This is the result of the for loop.

08:14The result of the for loop.

08:16The result of the next function.

08:18Again,

08:20the result of the for loop.

08:22Now, the code of robustness

08:26is not only for error handling.

08:30It will not break.

08:32The item milk is finished.

08:34The price tag is left.

08:36The price tag is left.

08:38The item milk is not finished.

08:40The price tag is left.

08:42The price tag is left.

08:44The two lines are left.

08:46However,

08:48کہ آپ نے iterator لگایا next next کرتے گئے

08:50لیکن جب last آیا تو وہ break ہو گیا

08:52code

08:52تو یہ for loop basically under the hood

08:55اس طریقے سے کام کرتا ہے

08:57کہ جو بھی آپ اس کو object دیتے ہیں

08:59اس کو وہ ایک iterator میں convert کرتا ہے

09:01اور next next کا function اس کے اوپر لگاتا جاتا ہے

09:03اور جو بھی block of code

09:05یا جو بھی functionality آپ perform کرنا چاہتے ہیں

09:07اتنی دفعہ

09:08یا اس object کے اوپر

09:10اتنی دفعہ

09:11یا اس object کے اوپر

09:13وہ functionality run کرتا ہے

09:14ابھی میں نے اس object کے اوپر ایک functionality run کی

09:16اور اگر یہ بھی نہیں کرنا چاہتا

09:18تو میں دیکھئے کہتا ہوں

09:20print let's say

09:22new list

09:24basically new list جو ہے

09:28آپ دیکھیں گے کہ سارے item print ہو جائیں گے

09:30میں execute کرتا ہوں

09:31سارے item print ہوئے

09:33اتنی دفعہ بھی ہوا

09:34اور ہم نے اس کے اوپر function بھی perform کیے

09:36یہ آپ کو پتہ چل رہا ہے

09:371,2,3,4,5

09:391,2,3,4,5

09:425 times یہ execute ہوا code

09:44اور 5 times اس کو price tag بھی لگی

09:46make sense

09:47تو اس کو summarize کرتا ہوں

09:49میں آپ نے دیکھا

09:50کہ شروع شروع میں

09:50ہم نے ایک دکان کھولی

09:52اور دکان پر ہمارے پاس

09:54مسئلہ یہ تھا

09:54کہ ہمارے پاس بڑے بڑے بہت سارے items تھے

09:56اب میں نے کہا

09:58کہ اس طرح کرتے ہیں

09:58کہ ہر item کے اوپر

09:59price tag تو لگانی ہے

10:00customer آئے گا

10:01کل price دیکھے گا

10:02اس کے اوپر تو وہ price tag لگانی ہے

10:03price tag اچھا

10:04تو ایک تو طریقہ یہ تھا

10:05کہ price tag یہ کرتے ہیں

10:07کہ ہمارے دکان کے اندر

10:07جتنے بھائے item پڑے ہوئے

10:08ان کو index دے دیتے ہیں

10:09اور اس کو اوپر price tag

10:10concatenate کر دیتے ہیں

10:13لیکن یہ robust نہیں تھا

10:14ہمارے پاس

10:15let's say

10:15hundred thousand

10:16جو چیزیں پڑی ہوئی تھیں

10:18اور ان کے اوپر

10:19اس طرح لگانا

10:20was not cumbersome

10:20تو میں نے کہا

10:21کہ اس طرح کرتے ہیں

10:22اس کو iterator میں

10:22convert کرتے ہیں

10:23next next function

10:24call کرتے جاتے ہیں

10:24کام ہو جائے گی

10:25لیکن اس میں بھی problem تھا

10:26ایک تو code بڑا ہے

10:27دوسرا یہ کہ

10:28code break ہو جاتا ہے

10:29جب item ختم ہوتا ہے

10:30تو پھر

10:31اس کا solution

10:31یہ نکلا کے

10:32ہم for loop

10:32use کر سکتے ہیں

10:33جو کہ بہت ہی

10:34robust ہے

10:34اور automatically

10:35ہمارے لیے

10:37وہی کام

10:37وہی functionality

10:38perform

10:39تو ایک simple

10:41summary میں

10:42اس طرح سے

10:42for loop کو

10:43represent کروں گا

10:43کہ for loop

10:44ایک servant کی طرح ہے

10:45جو one by one

10:47آپ کو item

10:48return کرتا ہے

10:49one by one

10:49item return کرتا ہے

10:51اب آپ

10:52اتنی دفعہ

10:53کوئی اور

10:53code perform

10:54کر سکتے ہیں

10:55جتنی دفعہ

10:55وہ one

10:55code آپ کو

10:56return کر رہا ہے

10:57item یا پھر اس

10:58item کے اوپر

10:59کوئی functionality

11:00perform کر سکتے ہیں

11:01اب جو بھی

11:02code آپ لکھتے ہیں

11:02وہ for loop

11:04کے اندر

11:05یہ دیکھئے

11:05یہ جو بھی

11:06code for loop

11:07کے اندر آئے گا

11:08وہ for loop

11:09کی اندر

11:10اندر run

11:12ہوگا

11:12make sense

11:13اوکے جی

11:14excellent

11:15تو میں اس کو

11:15یہاں پہ کرتا ہوں

11:16close

11:16to see you in the next one

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