[donat2]

Hi,

I'm trying to write a simple python script and it doesn't work.

The goal of this script is to change the color of duplicate read nodes (so that I can delete those duplicates). That would allow me to drag and drop without worrying if I already have those read nodes, then run the script and delete the duplicate nodes.

Here's the script :

import nuke
for n in nuke.selectedNodes():
    if n.Class() == "Read":
        for m in nuke.allNodes():
            if n.knob("file") == m.knob("file"):
                n.knob("tile_color").setValue(0xe81414ff)

Nothing happens when I run this in the script editor. Can someone point me my mistake ?

Regards

[michaelmovies]

Well first off you're trying to check x.knob('file') without .value() at the end ... x.knob('file') returns the knob itself, not its value ... so your if statement is always False, as the two knobs are not in fact the same knob object.

Second you're going to find this fails because most nodes don't have a knob('file') and you'll get an error returned if any node in the selected group (allNodes) doesn't have a 'file' knob ... but in this case it's not reaching far enough to hit the error.

Try this:

import nuke
from random import randrange

# minCol and maxCol restrict color range
# 1 (full black) to 109951162776 (full white)
# stepCol defines how large of a step between iterations

minCol = 1
maxCol = 1099511627776
stepCol = 1024

selRead = [i for i in nuke.selectedNodes() if i.Class() == 'Read']
if len(selRead) != 0:
    for m in selRead:
        setCol = randrange(minCol, maxCol, stepCol)
        allReads = [i for i in nuke.allNodes() if i.Class() == 'Read']
        for i in allReads:
            if i.knob("file").value() == m.knob("file").value():
                i.knob("tile_color").setValue(setCol)
else:
    pass

[donat2]

Thanks a lot Michael

I see that in your code you create two lists variables with list comprehension: selReads and allReads.

The allReads variable is created inside the first for loop. Is that mandatory ? Or could you define those two lists first, then proceed to the loop inside the loop ?

(Sorry if this is off-topic, I realize it's purely a Python problem unrelated to Nuke. I googled things like "nested loop scope python" but didn't find an answer)

Regards

[michaelmovies]

Originally Posted by donat2

Thanks a lot Michael

I see that in your code you create two lists variables with list comprehension: selReads and allReads.

The allReads variable is created inside the first for loop. Is that mandatory ? Or could you define those two lists first, then proceed to the loop inside the loop ?

(Sorry if this is off-topic, I realize it's purely a Python problem unrelated to Nuke. I googled things like "nested loop scope python" but didn't find an answer)

Regards

Hey no problem ... vfx is as much about python these days as python is about vfx.

Nope, it's totally not mandatory ... in fact the only reason it's there is cause I was originally doing a variant where I was going to not change the color of the selected read, just the duplicates ... and well it all gets a bit complicated, but I really just wanted to answer the question in the shortest amount of time.

Actually to be most efficient in this case, allReads should be initialized immediately after the if len(selRead) != 0 statement. That way if selRead fails (there are no reads to check) you never bother wasting processor cycles on allReads, but it avoids the multiple duplications I've accidentally forced it to do in this case. List comps are very fast, but it's still not worth duping the work ... if I'd kept going down my original path I'd have needed to, but with the code I ended up with it's redundant.

Good catch.

Michael