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Hello and welcome to this session on Python and six

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said is an on our door collection of data with no duplicate elements.

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Until now we have talked about different sequences in python like Lis tuples dictionaries as you can

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see here.

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The elements in a list are the tuple or a dictionary and not unique.

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So there aren't duplicate items in all of these data sequences but coming to a set it does not contain

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a need duplicate element and the elements in a set of UN ordered unlike lists and tuples because sets

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cannot have multiple occurrences of the same element.

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It makes it highly useful to remove duplicate values from a list or a tuple next set.

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I did a durable and mutable so we can add or remove elements from a set we can also perform common mathematical

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operations like unions intersections symmetric differences using set.

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We will have a detailed discussion on these operations in the coming up session.

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You define a set containing values using curly braces like this and there can be any number of items

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in a set and they may be of different types such as integers flawed tuple strings etc. But the elements

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in a set can not be a mutable element like a list or another set or a dictionary.

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And if you want to define an empty set in Python this is how you do.

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Say for example said B is an empty set that gays you can call the in function set like this.

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You do not use the curly braces but no values to define an empty set because this is resolved to define

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an empty dictionary so here in the Jupiter notebook I have defined a set E and the elements in the set

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a are not unique.

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So let's execute this line and then display said e as you can see here.

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The duplicate elements in set a.

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Has been removed because multiple occurrences of an element are not allowed in a set and a set can also

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be used to remove duplicate items in a tuple on a list.

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So let us pass a list to the built in function set.

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We'll look pass the list containing these forward values.

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See that the duplicate elements have been removed from the set and in order to define an empty set you

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call the built in function set like this.

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And then if we check the type of set B that is the data type does it at dawn these data types at say

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for example you define another set using the curly braces without any values and then execute this line

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and then check the data type offsets see.

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So as you can see does return the data type the because your dick empty curly braces are reserved for

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defining empty dictionary and then we have also discussed that the elements in a dictionary can be of

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any immutable later type such as integers flawed strings tuples but B can not have mutable elements

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in a set.

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Say for example I now try to change d set E..

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I'll try to add in a list here.

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D then execute.

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So you have deed type error here.

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Python has raised up type error so meaning you cannot have a mutable data type in a set.

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So as we have discussed a set is created by placing all the elements inside curly braces separated by

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commas or you can use the built in function set we will discuss the different methods that can be used

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on set the add method can be used to add elements to a set if you want to add a single element we can

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use the ad method.

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So using the add method we can add immutable elements to a set.

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And here we have called the add method on set E.

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Let's display set a so as you can see the element ten point 0 has been added to the set and also the

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set to a hill did not retain the order in which we have defined the elements because set at an unordered

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collection of data if you want to remove all elements from a set you can use the clear method and then

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we have the update method the Update method can take tuples less strings or other set as it argument

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and this method removes any duplicate.

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So let us add the elements in a list to dissect a.

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So using the update methods I am gonna pass a list one to two.

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One and then five common nine.

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So let's execute this line and then display set a the update method as you can see has included unique

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elements from the list in to the set a the list itself is not added as a single element in date set

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likewise you can add elements from two different set.

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So let's define another set here.

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Set B contains elements such as

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point eight nine dot or forty five dot o.

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So if you want to add elements from say B to set a you can use the update method.

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The argument should be said B.

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Now letters display set a

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so as you can see since all the elements and set B are unique the elements have been added to set a.

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Then if you want to remove elements from a set you have the discard method and the remove method.

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So using the discard method I'm going to remove one of the elements here.

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So I'm going to remove this element and then displace it a say for example the element that you want

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to discard from this set is not existing in on set is since a dot eight is removed from the set.

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Let's try to discard this element again and as you can see there is no exception raised when you tried

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to discard an element which is not existing in a set but coming to the remove method if we tried to

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remove the same element a dot aid from said a it is going to raise an exception key error.

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And then you also had the pop metal that can be used to remove an arbitrary element from a set so this

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element has been removed from the set.

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Let's now display the set E.

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So as you can see the pop method removes a random item from from a set and then you can use the Lent

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function to calculate the length of a set.

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So since there are 10 elements the lend function has returned 10 and we have discussed before that a

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common use of set and python is computing standard mathematical operations such as union intersection

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diffidence and symmetric difference.

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So let's discuss about these methods in detail.

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So here I have defined to set set C containing the element one two three four and five and then said

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D contains the elements two four six eight and 10.

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Now I want to find out all of the values which are existing in set C and set D.

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So I want to find out all the unique values in these two set.

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So that means I want to retrieve these values in this area.

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In order to retrieve these values I can use the union method.

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Set C union said D.

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And this is going to retrieve

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one two three four five six eight and 10.

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So here in my Jupiter notebook I have defined these two sets set C and set D.

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Now I want to find out all the unique values from these two sets so me will use the union method to

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retrieve all the unique values from the set.

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So I'm going to pass set D as an argument to the union matter and then execute.

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As you can see here the union method has returned a set of all of the values that are existing in set

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C or said D or both.

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Next if you want to find out the elements which are common to set C and said D.

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So I'm talking about the values in this area in order to get these values we can use the intersection

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method so set C dot intersection and we are going to pass the set D as the argument to this method and

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then execute.

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So these two elements to unfold add the common elements in these two sets.

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Next if I want to retrieve the elements in set C which are not existing in set D that means I want to

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retrieve the values in this area.

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So in that case I can use the different method in order to the G d values 1 3 and 5 the elements 2 and

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4 add existing instead D.

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So I do not want to retrieve those values

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so said see Daud diffident is the method you pass.

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D said D as the argument and this is going to retrieve all of the elements in said C which are not part

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of said D.

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So as you can see these elements 1 3 5 are unique to set C.

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Next say for example I want to retrieve all of the elements that are by use of exactly one of the two

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sets but not both.

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So I want to retrieve all the elements in this area and this area as well.

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So I want to retrieve all these six elements.

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And because 2 and 4 are common to set C and set D I do not want to retrieve these two elements.

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So if I want to retrieve the values that are existing in one of the two sets but not bored I can use

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the method symmetric difference.

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So let's call this method symmetric difference so when I execute this say I'm going to retrieve the

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elements that are existing in one of the two sets but not put the next method that we're going to talk

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about is the is disjoint method.

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And this method returns true if the two sets have a null intersection that means both of the sets do

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not have any element in common.

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So if we call the method is does join and pass these said these is a argument.

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This is going to return false.

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That's because there are some common elements between these two sets set C and set D.

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No let's display said B.

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Let us now see is disjoint method returns then we pass said B as an argument.

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So said C Dart is disjoint set B.

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So this method does return true because there are no common elements between set C and set B

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and the next method is subset.

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But you don't draw if another set contains this set.

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So here I have called the is subset method on set C by passing said D as an argument and this is returned

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false because not all of the elements in set C and existing in set D similarly B have the is super set

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which returns true if this particular set contains another set.

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So I'm gonna call inequality is super set method on set C and I have passed a set containing these two

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elements 1 and 2 to this particular method.

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And since these elements are existing and set C this method has returned true.

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And then we can also perform membership test to check whether a specific element is contained in a set.

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So for example I want to check if one is existing in Set C in Set C so because the element 1 is existing

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in said see this as return true.

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Let's say 1 not in Set C so they should return false.

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Next we have the sorted function that can be used to sort the elements in a set.

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So we have talked about set and set an unordered collection of data.

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But if you need to get these values from your set in an ordered form you can use the sorted function

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which outputs a list that is ordered.

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So here I have defined set e containing these elements and they add in an unsorted audit.

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So if you want to saw the order of the element in Set A.

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We can use these altered function so we will look past set into this function and this function sorted

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is going to return these elements in ascending order.

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And this brings us to the end of the discussion on the method that can be used on sets.

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You can either it through a set just like we do for other data sequences such as lists dictionary and

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tuples so we can use a for loop to retrieve all of the elements in a set so here I have defined a set

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said each containing different elements.

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Now using a for loop will print all of the elements in set E..

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So for x in set e meaning for each element and set e print the element so print x.

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So as you can see here the order in which these elements have been printed using the for loop is different

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from the order in which we have defined set E.

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That's because the element in a set are in an on ordered form.