Nuke; Python For Artists; Python Panels Callbacks - PartB Video Lecture | Create Visual Effects with Nuke - Professional Skills

and grab a fresh instance of that panel
to see if everything is working as
expected so I'm just going to select a
few nodes here and change stuff and now
you can see that this automatically
triggers the changing of the knob here
and if I type something that is actually
contained in those knobs like SC 20 and
just change focus away this updates and
tells me that there's one node called
read for in my selection so let's go all
if I go all nodes I now found two
matches because this guy here has SC 20
in it as well so the last thing to do
obviously is making this replace button
do something slightly more beneficial
than just printing its name into the
terminal so let's go back one more time
and in our callback will extend the if
statement by an eel if case so we'll go
else if knob equals self dot replace
then do something so the subsequent code
is only going to happen if the replace
button is pushed the replace button
obviously needs to cycle through all the
knobs that we found according to our
search string and then perform string
replacement on them because I don't want
to run the search result function twice
I'm actually going to modify this line
slightly here and save the result that
is returned by the search result
function which is the matching knobs we
need to operate on so before we go any
further let me just quickly add an
attribute up here so I'll go self dot
matches for example and that's going to
hold all of our knob matches but
initially it'll just be none and then
when we perform the search in our
callbacks we simply assign the result of
the search result method to that
attribute so we go self-taught matches
equals self search result etc so the
moment this label updates the respective
result is always stored in our matches
variable attached to our panel so when
the time comes that the user actually
hits replace we can now simply loop
through the result of self matches let's
do that for k in self dot matches so
this will cycle through all the matching
knobs and in here we finally need to do
the string replacement so I'm going to
create a variable called new STI full
new string and I'll use the regular
expression module for that so I'll go
REE for regular expression sub for
substitution and because this module
isn't included by default we need to
import that at the top of our code again
like so right so now we've got access to
the re module and the sub method of the
regular expression module works in a way
that the first argument is the string
that you want to substitute the second
argument is the string that you want to
substitute it with and the third
argument is the string that you actually
want to modify so let's go ahead and
give it the first argument which in our
case will be self dot search st r dot
value that's what we want to search for
and we want to replace it with self dot
replace as TR to add value add the
string we actually want to modify with
all this is the current novice value not
the current knob but the knob found by
our search result function so that's
doing the string modification and it
stores the new string in the variable
new STI doesn't actually modify the
knobs value just yet we have to do that
right after that so we go k dot set
value new str like so and now we run the
whole thing again and it spits out an
arab because i forgot to close my
regular expression call here so let's
try that again that's better and bring
up a new instance of the panel
and now let's once again select staff
and type SC 20 in here we already know
that that's working so that's finding
two nodes in all let's say we just want
to operate on selected nodes so that's
only one match and now we want to
replace the whole thing with let's say
as c 21 there you go