Part 76 Working with generic list class and ranges in c# Video Lecture | C sharp: Enhance your Skills (English) - Back-End Programming

this part 76 of c-sharp tutorial in this
video we'll discuss working with generic
list class and ranges this is
continuation to part 74 and 75 so please
watch these videos before proceeding in
this video we'll be discussing these
fringe functions first of all let's look
at ad range method now if we want to add
an item to the list then we use add
method but this method allows us to add
only one item at a time now if I want to
add a list of items to the existing list
then we can use this ad range function
let's look at that in action so here is
the customer class that we have been
working with and to this class I have
introduced this type property so this
type of property is going to tell
whether the customer is a retail
customer or a corporate customer and
within the main class I have created
five instances of the customer class so
we have customer one customer to
customer three so these three customers
are of type retail customer as you can
see here and then customer four and
customer five or corporate customers and
then what I have done is created two
lists the first list contains customer
one customer two and customer three
these three customer objects are retail
customers and I have created another
list called list corporate customers and
to this list I have added customer four
and customer five and if you look at
this add method it allows you to add
only one item to the list at a time okay
now let's say I want to add this list of
customers to this list then we can use
add range function so list customers dot
add range and look at that it expects my
and your number of customers to be
passed so I can pass this list to this
function and then the items that are
present in this list will now be added
to this list so at this point list
customers should have five objects
within that let's verify that so for
each customers see
in lists customers let's print the
details so I have already typed the code
to print the ID name salary and type of
the customer so let's go ahead and run
this and we should get five customers
and look at that corporate customers you
know is added at the end so ad range
function allows us to add a range of
custom objects to the list alright let's
look at using get range function now to
retrieve an item from the list we
generally use that items index so for
example if I want the first item from
this list then we pass index zero and
look at what it is returning it's
returning a customer object only one
object back so when we use the index we
only get one item at a time out of that
list now if I want a range of elements
meaning a list of elements then we can
use get a range function so when I say
get range look at that I can basically
specify the starting index position from
which I want the items and then how many
items I want okay but let's say I want
you know corporate customers from this
list corporate customers start at index
position three okay zero one two our
retail customers and three is corporate
customer so from index position three I
want two items and look at the return
type of this function it's actually
returning a list of customers back okay
so let's include that in a variable of
type list customer and let's call it
maybe customers and then let's use a for
each loop and verify the output let's
call it for each customer see in
customers
let's go ahead and print their ID name
and salary and type okay so let's run
this now and we should get only
corporate customers on the other hand if
I want only the retail customers then
retail customers start at index zero so
from index zero
I want three items so now we should get
only the retail customers all right now
let's look at using insert arrange
function so first of all let's get rid
of this function okay so at the moment
list customers has only three items okay
because if we got rid off that line
add range so list customers only has
three customer objects now if I want to
insert an item into the list then we use
insert function and obviously we need to
specify the position of the index at
which you want to insert that item so if
I want to insert an item at zero at
index so I specify zero and then pass
the item that I want to insert but then
this method allows us to insert only one
item at a time okay now is it possible
to insert a list of items absolutely
again use insert range function okay so
all these range functions I love you to
operate using a list so let's say I want
to insert these corporate customers at
the top of the list then I specify the
index as zero and then you need to
obviously pass your list which is list
corporate customers and then let's loop
through this list of customers and see
if we get both corporate and retail
customers and then corporate customers
has to be on top because we have
specified the index position as zero on
the other hand if you want them to be
inserted at the bottom then specify the
index position as three because the
first three positions are occupied by
retail customers so now corporate
customers should be at the bottom
right now let's look at using this
remove range function now there are
several functions that help us to remove
an item from a list first of all I can
use this remove function now when we use
a remove function then we will have to
specify the item that we want to remove
so if I want to remove customer one
object so I simply pass you know the
object that I want to remove here in
this case customer one
so now customer one object will be
removed from the list so we'll only have
four customers to retail and to call
plate okay but then again this function
allows us to remove only one item at a
time and then we have this remove add
function as the name States you can
remove an item at a specified index so
when we use a remove add we need to
specify the index position at which we
want to remove the item let's say I want
to remove the last item from the list
then the index position is 4 so let's go
and pass that so the last item which is
one of the corporate customers should be
removed from the list again this remove
add function allows us to remove only
one item at a time but there is another
function called
remove all this allows us to remove
multiple items from the list
but then in order to use this function
we need to specify a condition now let's
say I want to remove all corporate
customers then I can use this remove all
and specify a condition so we can pass a
lambda expression here let's say X such
that X dot type equals you know we want
to remove corporate customers so let's
pass the type so corporate customers
so we get only retail customers so if
you want to remove retail customers just
pass that as your type and retail
customers will be removed okay now
there's another function remove range so
this allows us to remove a range of
customers a list of customers okay so
for example let's say I want to remove
corporate customers now corporate
customers start at index position three
so from three from the index position
three remove two items so what should
that do that that should remove two
corporate customers from the list so we
only get retail customers on the other
hand if you want to remove the retail
customers then start at index position
zero and then remove three items look at
that both of the retail car I mean all
the retail customers are removed and
only corporate customers are left all
right that's it for today thank you for
listening have a great day