How to use METHODS in Pine Script

g'day Traders today we're answering
another question from a student in the
Mastery course and this student wants to
sort an array of EMA values but also
keep the corresponding ticker ID
associated with that value while being
able to interact with the arrays so for
example in this case we're sorting the
array in ascending order so the lowest
EMA value is first the highest is last
but we're also keeping track of which
ticker each value corresponds to now the
methods I'm using to achieve this are
quite interesting and the script
actually makes use of a brand new pan
script feature that was released a
couple of days ago called custom methods
so in this video we're going to be
covering how to create custom types data
types and we're going to be covering how
to create a custom method and this is
the new feature I'm speaking of method
syntax comes to panscript so if I scroll
down here the blog post here says the
dot notation used for extension methods
in other languages is now available in
Pine scripts I love the guys that write
these blog posts they're clearly
programmers they're not speaking to
Traders they're speaking to programmers
with all this jargon basically what this
means is if we're using something like a
box for example excuse my childish
writing with a mouse the dot notation is
this so dot new
and then we can use a function or it's
actually a method but a function and a
method are pretty similar you don't
really need to know the difference in
pinescript to be able to use them
properly if I scroll down here see this
line here Source array dot push value in
the past you would have to do something
like this array dot push and then pass
in the array ID and then the value but
now with this new method feature added
to Pine we can do exactly the same thing
by just saying array ID dot push value
now in this particular example it
doesn't make our code that much more
efficient but in a complex script you
can see how this can really help tidy up
our scripts and make the code a bit more
intuitive to read especially so without
further Ado let's jump into the pine
editor and start writing out the script
all right so here's our starting
template all I'm doing here is creating
a regular indicator script with overlay
to true so we're drawing over press
action and we're getting five ticker
inputs or symbol inputs it doesn't
really matter what these are they could
be anything but for today we're sticking
with Forex so we're just working with
oanda we've got euro dollar dollar Yen
New Zealand dollar pound dollar and gold
and what we want to do is get the EMA
value for each of these the 50 EMA on
the daily chart daily time frame so
we're going to be using the security
function here then we're going to insert
all of those EMA values into an array so
we're going to be creating an array
based on a custom type so before we do
that we need to Define
our custom type that stores both
the EMA value and the ticker ID so to do
that we use the type keyword doesn't
matter what you call this I'm going to
call it EMA underscore sorted wow if I
can spell EMA underscore sorted and now
we need to define the data types that
are stored within this overall class
type so I said we need to store the EMA
value and the ticker value so that's a
float value and a string value so we can
just declare these values in here so
float EMA value and string ticker
that's it we have defined our custom
type now we can create a type based on
this by simply saying EMA sorted my
custom type equals EMA sorted.new
and then it takes the float value
and a ticker string and so now what we
need to do is create five of these for
each ticker ID and get the EMA value
using the security function for each but
before we do that let's declare our
custom array so for this array I'm going
to make it persistent so it doesn't
reset on every new bar on our chart
that's because on each bar we're going
to be setting each of these five values
in the array so we don't really need to
recreate the array on each new bar this
will just make our script compile and
run a bit faster so to Define any array
the syntax is usually like this array
and then open
arrows and then the data type of the
array needs to go in between these
arrows so if we're going to create a
array based on a custom data type we
need to paste our data type name into
this array syntax and then I need to
give it a name so I'll just give this
the name of just EMA array and then we
need to set it to array dot new open
left arrow and then we need to put the
data type in again
and also specify the size of the array
now this is optional but for today we're
going to set it to five so we have an
array based on a custom data type with a
total of five elements and that's going
to be these five custom data types so
now we have our array declared let's get
our EMA values so since today's lesson
is not about the security function I'm
just going to copy this code over to
save time it's not that complex anyway
all we're doing is requesting data from
a security that is not this symbol be
passing our symbol IDs our ticker IDs
the time frame we want to get this data
from and then the expression the data
that we want to request from the
security in this case that's the 50 EMA
based on closing price from the daily
chart for each ticker or symbol now we
have these five EMA values
the next thing to do is completely
optional but because it makes it easier
to understand what's happening we're
going to draw all five of these onto the
chart this is obviously optional we
can't really do much with this
information since this is all EMA values
for markets completely unrelated to this
one but at least we can see our values
up here now and what we want to do now
is add all of these to an array and sort
them in ascending order so lowest number
to
the highest number in order to do that
we need to insert all of these values
into our array so that's going to look
like this now notice that for the first
time as of a couple of days ago we can
now use dot notation with arrays to
interact with those arrays so as I
mentioned earlier in the past in order
to do this sort of thing in order to set
the first element of this array to any
value we would have to write array dot
set
and then pass in our array ID then pass
in the index then pass in the value but
now we can skip this part and just
simply put dot and then the method that
an array typically has access to and
here we go now it's not that amazing but
for any of you experienced programmers
out there you know that this is pretty
cool feature then I'm surprised it took
this long for the trading view
developers to add it to Pine it's much
more intuitive this is much more similar
to traditional programming languages now
the syntax we can use here is much more
intuitive for most programmers out there
who work with the more popular languages
like python Java JavaScript C and all of
those sorts of languages so anyway we
need to set all five values here so I
can copy and paste this line a few times
remember array values elements start
from zero the first index is zero so
zero one two three four gives us five
elements we need to pass in the value of
each EMA and each ticker string so we're
setting each array element in our custom
data type array to all of these values
and we're creating a new EMA sorted type
passing in the email value in The
Tickler for each and now we have
everything we need in order to
manipulate this data in this case we're
going to sort the data in ascending
order and to do that we're going to use
the new method
feature now methods work pretty much
identically to custom functions so a
custom function will look like this
let's say you have value 1 value 2.
and you want to return whatever value
one multiplied by value 2 is this is how
you would Define a custom function that
multiplies these two values and outputs
them and then we could plot this by
saying what's 1 times 2.
save my code and we're getting two
plotted up here using this custom
function now to do a method a custom
method it's pretty much the same syntax
except we need to use the method
keyword in front of this and so our
custom method is going to be called sort
custom array and now this is where
things get pretty complicated
particularly for this lesson if we make
the very first parameter of this method
an array then we can call this method by
using the
dot notation I showed you just before
so we can use this syntax to sort out
EMA array if we make the first parameter
in this methods parentheses a custom
array like this and now we need to use
the same custom function syntax equals
sign followed by a right arrow enter Tab
and then anything within the scope is
executed by this method when we call it
now normally if you're just working with
a standard float array
um like this let me comment this out so
this compiles properly
if we had an array like this
test array equals array float
array.u
float
five values if we had a normal float
array like this we could simply just use
the test array.sort
function and this would sort the values
in ascending order however with our
custom data type this function won't
work so if I paste EMA array in here our
script is now broken because biascript
doesn't know how to sort an array filled
with data types of this nature it
doesn't know that we want to sort the
array by EMA value so what that means is
we need to write our own code for
sorting the array elements and that's a
little bit tricky it's not too crazy but
it does require some pretty scary
looking code if you're new to buying
scripts for those of you who are
experienced this won't be that bad but
we just need to Nest two for Loops
within each other and then these two for
Loops will will cycle through the array
and compare all the elements to each
other and then set the array elements in
order of their values in this case
ascending order so to do this we need to
create our first which is going to be 4i
equals 0 2 Source array dot size minus
two I'll explain why it's made is two in
a moment but now we need to Nest a
second for Loop here and so the second
for Loop is going to Loop within this
for Loop it needs to have a different
index value obviously we can't call this
I so we have two for Loops here the
second for Loop is going to be set to
the first for Loops index plus one and
We're looping two
our source array dot size
-1 and so now what we can do is we can
check if Source array dot get I so
that's this first for Loop value or
index array index so we get that value
now remember when we get this value it's
going to be this data type our custom
data type so what we can do here is say
EMA value
if
the first Loops EMA value is greater
than the second loops
BMA value then we need to swap their
positions in the array so to do that we
need to create a temporary data type
here called temp
equals Source array.get I and then we
need to set Source array dot set I to
this for Loops element so I can copy
this here and change this to J
and then we need to set the
second
for Loops array element to our temp data
type so we're essentially swapping these
two elements position within the array
because they are not in the correct
order so now if I save my code let's
just make sure this compile is okay
there we go no problems now what we can
do is
call this custom method
on our custom data type array
so we can sort email array we could also
call this function like this
email array
that would do the same thing so now you
can understand why methods are very
similar to functions in fact if we got
rid of this
and at the end of our for Loop we just
return the source array we could do
something like this so this is how it
would work in the past you'd have to use
a custom function and you'd have to call
it like this but now that we have the
new method functionality we can simply
do that and that makes coding a lot more
efficient when working with complex
scripts like this so
here we are defining our custom array
sorting
method we're calling it here the final
thing to do is draw this data to the
Chart so I'll just copy this code over
to save time here we're just checking if
the script is running on the final bar
on our chart we're creating a array text
it's blank to begin with and then we
Loop through all of our Ray elements and
we append or add the array elements text
to this value and then finally we create
a label with the text so that we can see
what the heck's going on with our custom
function so now if I save my code we
should be getting the script to be sort
of the beginning of the video there we
go
sorting everything in ascending order
using a custom method a custom data type
and a array based on that custom data
type so we covered quite a few Advanced
Pine script Concepts in today's lesson I
hope you guys found this interesting
just to wrap up the lesson I want to
cover a couple things first of all this
probably looks a bit complicated we can
get rid of this line of code here and
just add on a new line at the end of
this so now if I save my code the label
will still be drawing but we have a
blank string at the bottom of the label
that's why I added this uh extra line
here this just checks if this for Loop
index is equal to the final Loop if it's
on the final Loop then we don't add a
new line character to the label text and
that's obviously purely optional just
makes the label look a little more
symmetrical for all of you OCD Traders
out there what else is there to cover uh
with the for Loop here the reason why we
have to subtract 2 from this original
for Loop is is because if we don't do
this we get an array index out of bounds
error on the final Loop if I change this
to -1 and save my code the script will
no longer compile because in
array.getfunction index 5 is out of
bounds so that's why we need to subtract
2 from our original Loop but we don't
need to do that for the second Loop
because the second Loop Loops up to the
final element where this Loops up to the
second final or second last element and
then this for Loop runs on that second
last element and we're adding one to the
original array index and so this for
Loop runs on the final array element
even though this Loop doesn't Loop up to
the final element hopefully that makes
sense it's really hard to explain this
sort of stuff but if you play around
with this code and try sorting your own
custom data types I'm sure you'll figure
out what I mean with practice the final
thing I want to do before we end this
video is I want to show you guys how we
could add
a optional Boolean value to this method
called ascending and ascending is always
going to be set to True by default so
this is how you declare a default
parameter now if I save my code
everything will compile without any
problems if I get rid of this equals
true however now we have a problem
because this is no longer an optional
parameter and our function call our
method call here requires us to specify
whether ascending is true or false
like so but for this example that I'm
about to show you we're going to leave
this as true by default and then what
we're going to do is check in this if
statement this value and if this value
is false we're going to sort the array
by the opposite direction descending
order so what we're going to say here is
we're going to say if ascending and this
condition is met the element of I is
greater than the element of J if that's
true we swap the elements or and then
I'm going to put this on a new line just
because it's easy to read otherwise it's
going to be off my chart here to split a
if statement across multiple lines you
need to press space after you hit enter
otherwise you get a syntax error and for
the second check the second condition
we're going to check is ascending not
true and are our array elements in the
opposite direction so is element I less
than element J if so then this for Loop
will sort the array in descending order
so now if I put false within this
parameter within this methods
parentheses and hit save this list will
now be sorted in the opposite direction
so now we have the highest number at the
top or the first element in our array is
the highest number all the way down to
the lowest number you could also achieve
this by just calling EMA array dot
reverse because we're sorting in
ascending order so we could just reverse
the order of our array we want to but I
thought it was cool to show you guys how
we can add this optional parameter into
our method so remember if we don't
specify a Boolean value here then it's
going to use this default value which is
true and we're going to sort the array
in ascending order anyway my brain is
fried after this video I hope yours
isn't but it did take me a while this
morning to figure this out so I've been
coding for a couple hours I'm going to
go take a break now as always the source
code will be below if you want to play
around with this I hope you found this
video interesting if you did make sure
to subscribe hit the like button all
that YouTube stuff if you want to learn
more about planescript check out my
website pinescriptmastery.com there's a
free course there for all of you
beginners if this went way over your
head then you might want to start there
it's completely free and has several
hours of content covering the basics of
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as always I hope you have a fantastic
weekend best of luck with your trading I
love you guys thanks for being here
thanks for supporting the channel and
I'll speak with you in the next video
take care