Detecting Key Trading Session Levels in PINE SCRIPT!

hey Traders and welcome back today I've
got a quick video Lesson for you guys
I'm going to answer a question from a
student of the Mastery course and here
is the question I'm not sure if they
would want me showing their name
definitely not their email so I've
blocked that out but anyway the question
is what I wanted to check was how can we
find a high and low in regular trading
hours when the cash Market is open let's
save for Dax which is a German index
they want to get the high and low
between 8 AM and 4 30 PM GMT instead of
the whole 24 hours so this was in
response to my previous lesson I put on
the channel which was a day trading tool
made in pinescript and that was this
script here now the script is drawing
yesterday's high that's the red line
yesterday's low that's the blue line and
this trading sessions opening price
that's the white line and then about a
60 ATR above and below that opening
price this is just to assist day traders
in gauging the volatility and potential
distance that a market might be able to
move during a trading session so go and
check that video out if you're
interested in this tool but anyway in
today's lesson I'm showing you something
slightly different and this script is
drawing the high and the low and the
closing price of yesterday's trading
session within a given time frame or
time session so a slightly different
application of the techniques taught in
the last video so I thought this was an
interesting application of time-based
filters and functions in Pine so I
figured I'd make a video about this to
put up in the course and on YouTube so
that we can all learn from this question
so let's get rid of this script again
there'll be a link in the video
description to that lesson if you're
curious let's open the source code of
the script and I'll break it down so in
order to track the high low and closing
price of a previous day's price action
within a Time session we can't actually
use the security function for this it's
not appropriate for this application the
security function is used for
referencing higher time frame
information and so in my day trading
tool I actually use the security
function to request yesterday's high and
low in this particular script that's not
appropriate because we don't want to get
the high and low over the past 24 our
period we want to get the high and low
based on a Time session so how do we go
about this if we're not using the
security function well let me explain so
the first thing I'm doing here is
getting our user inputs we're just
getting the session to Monitor and the
time zone we want to apply to this time
session this color session is just a
debug option and it will just paint the
background color of my chart to
highlight the zone that we're tracking
so you can see here using this trading
day as an example the low is saved and
the high is saved
and the closing price is saved and then
drawn over the next day's session but
I've left this off by default it's just
purely for debug purposes so the first
thing we need to do is determine if a
price bar Falls inside the specified
session to do that we use this little
function here I use this in all my
scripts that require detecting time
sessions so I'm not going to explain the
code here I've done that many times in
other lessons and in the Mastery course
but basically you can copy and paste
this line of code into any script and it
will detect if a bar Falls within the
given session it takes a parameter here
SES is the time session that you pass in
in this case it's going to be this
string here 8 AM 0-800 to 3 P.M 1500
this is the time session we want to
detect so in other words this string
will look like this when we pass in this
time session into this parameter
this is the string that we will be
passing into the time function now this
one two three four five six is the days
of the week so if you wanted to only
detect Mondays or Tuesdays or someone
you can put in the corresponding number
there so now that we have a function
that can help us detect when a bar Falls
within the time session we're looking
for the next thing we need to do is save
yesterday's high low and close to do
that I'm just using persistent variables
so the VAR keyword will make sure these
do not get reset on every new bar and we
can update them only when we need to so
these variables track price action as
it's traveling around through the
session and then when the session ends
we save the highest high over that
session the lowest low over that session
and the closing price of that session
into these variables and these variables
are the ones that get drawn onto our
chart on the next day's trading session
so hopefully that makes sense so moving
on the next thing we do here is create a
persistent Boolean variable and this is
used to reset today's high low close
tracking variables these variables here
so on the first bar of a new session
today's high low and close all get reset
so that we can update them for the next
day's trading session and we just keep
leapfrogging throughout price action so
to update these variables we check is
the current bar inside the session we
want to detect
so time session is this user input here
if the current bar Falls within this
session then this code gets executed the
first thing we do is check if this is
the first bar of a new session then we
reset today's high to the current bars
high and today's load to the current
bars low and we turn off this Boolean so
we set it to false that way we don't
keep updating today's high
on every bar we only want to reset these
variables on the first bar of a new
session that's what this Boolean helps
us to do so once this code gets executed
this Boolean is set to false and this
code no longer is relevant
and then this code becomes relevant and
this code is checking if the current
bars high is greater than the bar high
that we've saved into today's high
variable then we re-assign today high to
this bar is high
so whenever a bar exceeds our saved
session High
we save that new high and we keep
updating that until the end of the
session and then that gives us our red
line our blue line is the same but
opposite direction we're checking if the
current bar is low is less than the low
we've saved for today if so we update
that variable and that's it we're
tracking the session high and low and
then all that's left to do is save those
variables at the end of the session so
that we can draw them on the next
session now to do that we have this else
block of code so if we are inside the
session we want to detect this code gets
executed so if we're not in the session
this code gets executed now I just
realized I can move these into this if
statement here and get rid of this
Market high low close so if we are not
in the trading session we want to
highlight or analyze and this is not the
first bar of a new session then we save
today's high into yesterday's high we
save today's low into yesterday's low
and we save this final bars closing
price into yesterday's close then we set
this flag Boolean first bar of new
session to true
and now every bar that prints outside of
this session that we're detecting
this code will no longer get executed
we've already saved yesterday's
high low close and then when the first
bar prints inside the time session we're
looking to detect on the next day
remember we've set first bar of new
session to true and so the very first
bar that starts a new session this will
be true this code gets executed first
bar of new session is set to false and
we just keep repeating so every new day
we cycle through we save and update
today's high and low and then at the end
of the session we save all that
information and then all that's left to
do is plot it onto the chart and so my
code here is a little bit complicated
looking we could technically get rid of
all of this ternary operator stuff if we
wanted to
the problem with this as I've written in
the comment here if I save my code and
get rid of those ternary operators those
conditional operators you can see we
have these weird connecting lines now
connecting all of the sessions and it
just looks strange I don't like the look
of it at all and so to fix this I added
in this little bit of code here and all
this code does is it checks if
yesterday's high is not equal to
yesterday's high on the previous bar
that means that we just updated the
value and if we just updated the value
then we want to plot n a or nothing
otherwise if we did not just update the
value and this line is the same value as
it was on the previous bar then we just
want to plot that value and what this
will do if I save my code now is when a
new session begins we get a one bar gap
between our lines and it looks a lot
tidier as you can see it's just easier
to read and our charts are less
cluttered and then finally we have our
debug code here which just checks if
debug is turned on if it's turned on and
the bar that this script is currently
running on Falls within our time session
in the settings menu then we change our
background color to green with 90
transparency otherwise we do not change
the background color and then
um of course we also pass in the time
zone that we want from the settings menu
in this case that's TMT or UTC to pass
in a specified time zone we just add
that on to the end of our time function
here as a extra parameter if you omit
this then the time function will just
reference The Exchange time zone I
believe but anyway that's it for today's
lesson I hope you found this interesting
as always the source code will be below
if you want to learn more about
paintscript and take your trading to the
next level go check out my courses at
Pine streetmastery.com and with all that
out of the way I hope you have a
fantastic week good luck with your
trading and your coding and I'll speak
with you in the next lesson take care