Hi, this video is about Python list. We're going to discuss Python list Python functions and Python methods, and few examples related to each of them. As you know, we are using Jupiter notebook to code Python program. Now, what is a Python list is a collection of values and contain different types of data. For example, here I've created a list with the name students, and it has string numeric values, it could have another list, or any other type of object within this list. So you'd see so you see this is when I write students and create an output, it gives me the list of all the students along with their I've mentioned it just as a number.

Maybe these could be the result of a test Alice can have compound data type where you can group values together. For example, here I've created a variable quality With the list, and here it is mentioned, A and B, where a and b are very enter. So when I create an output for this list quality, it is going to give the values of a and b instead of the actual A and B, you notice that I have not put inverted commas alongside a and b because these are actually the variables and these has value assigned to it. And therefore buyten engine automatically recognizes that and creates an output. So that's very powerful. Next thing is again, quality with first index, it is going to give me an output on that index.

The index works like it's from zero and onwards 0123 whereas it also gets negative from the last element within the list and moving forward. So it has to actually type of indexes. The first one is from zero and onwards and the last one is from minus one and then onwards, but minus one starts from extreme right, less from any relation we can change values. Within the list we can add elements to list we can remove elements to list if we want to change elements to list we just have to identify the index and then assign different values to it. For example, here, we have selected the range from zero index to second index. Now, the second index or the index that comes at the end is exclusive, it means a number less than the end index is selected.

If two is given, it means the value of zero index and the value at one index would be selected. And these are given new values they and are so we had he and is on zero and one in Dec. Now we have d and R at these two indexes. If you want to add an element to the list, we can directly use plus sign alongside the element alongside the BD name of the variable and passing a new list after the plus sign so that would actually concatenate these two lists or maybe the lesson the first variable and the other list here. The question is a variable and it has a list assigned to it now, when we add plus sign and then pass to other elements within the list, it is going to concatenate these two lists in quality and risk that we just passed on.

And here you see the output is they are very tall and smart we can we can use the list function of death to remove any element at a specified index in the list. For example, here I use a specified index for to remove and from the list and this is when I did it, this it created an output they are very tall and it removed and and created smart. Another important thing in the list is when we create another variable and assign it to an existing variable here for example, I've created quality news, good news to you and i equal that to call it industry new that was an existing list. What it does, it actually creates a link between the same list that list in the memory is just as they are very tall, smart, and what it does is actually it has a Scientists list to two variables now call it industry new and quality underscore new to so if we change an element within this list it will also change the actual element in the list and when we call the other other variable it will output change less for example in quality industry new when we change it again too he is and then when we call quality English good new tube it outputs the updated list see so this is very unique feature in Python.

If we want to create a new list out of an existing list, we can use the method list to create a new list now if we create quality underscore new to is equals to list and we pass the existing list it is going to create a new list that has that has a separate allocation within the memory. So if we update an existing list and check this list, it would remain same Python list method. These are the methods and it can be used like name of the list with dot and the name of the method. It could be banned to add an element at the end of the lists and insert remove bop bop just removes an element at a specified index and returns it for example I've used it here quality industry new had these elements he is very tall smart and and when I used while he understood new top with fifth index it has been removed and and when we create an output from that it gives this so these are the list methods sought it creates a sorting within the ascending order reverse copy now in Python everything is object and each object has different methods.

For example, quality two I assigned this tall and this creates an object within Python and this is a string type object. Now when a string type object is created, we can use methods like capitalize replace, it should try Python engine automatically assigns the type for any variable that is created and when it assigns the type it has accordingly methods available for it. Similarly, when a tall variable is created and assigned it 1.3 it automatically creates a float for it a floating action And it will have these methods assigned to it. If a new list is created, it will have index count and other methods. Let's try quality two dot capitalized now you see that I signed it's Malti and overall, Tolbert, and when I used capitalized method or that variable, it can work that small t into capital T. If I want to know the object type or a variable, I can simply use this function of type and pass in the variable that I've created and I and the Python creates an output with the type of the object created here quality in this good new is a list object type.

And it just output that there are several built in functions for list within Python or any enumerate in a minute is a very unique object type. It creates a list of all the variables with the index. For example, we had the quality industry new variable that had the list key is very tall smarted five elements starting from zero index to fourth index. Now when we use the enumerate function, on it and pass this variable it will create a list of all the elements within that we build alongside the index of that element. Another example land function creates all the elements total of all the elements within the list. This is another example here we are creating a list with the for loop within it and creating an enumerated list of all the elements three to the power of x, we're for x in range 10.

So the range always starts from zero. So when there was the power zero applied to three, it gave one when power, one applied to treat give three, and so on and so forth. So up to from zero to nine, that was 10. From zero to nine to 10 numbers it applied as an exponent to number three, and it created a list. If you want to test if a particular element exists in the list, we just need to type in the name of the element in the name of 3d will, if it existed, it would print out true if it's not true. printout was here the three existed in the list or three it printed out true whereas a did not exist.

So it printed out false. This was all hope now you have better understanding and you move forward in understanding Python more quickly. Thank you.