The Foundry Nuke – Issues with `elif` and `else` statements

Question

So to make it simple, I'm writing a script in NUKE which aligns the selected nodes in the node graph into one straight line in the Y-axis. I'm having issues where I'm writing the elif statement which is either not functioning as I want to or it is giving me a syntax error.

So the basis of the function is:

ELSE STATEMENT - when selected only one node - error message pops up saying user has to select more than one node

ELIF STATEMENT - when selected two or more nodes which are in the same Y-axis - message showing they are already aligned

IF STATEMENT - when selected two or more nodes in different Y-axis - it should properly align all the nodes in a straight line

# Getting selected nodes and making them into a list

selNodes = nuke.selectedNodes()
list = []

for node in selNodes:
            n = node['ypos'].value()
            list.append(n)

# Defining the actual function

def alignY():

    # Aligning the selected nodes using average position of every node. 
    # Must select more than one node in order to get an average.

    if len(selNodes) > 1:

        total = sum(list)
        average = total / len(selNodes)

        for node in selNodes:
            n = node['ypos'].setValue(average)

    # Getting the position of a single node from the list
    firstNodePostion = list[0]

    # Checking position of the single node is equivalent to the average 
    # To prevent nodes aligning again)  

    elif average == firstNodePostion:
        nuke.message("Nodes already Aligned")

    # When no nodes or only one node is selected this message pops up         
    else:
        nuke.message("Select Two or more Nodes")

alignY()

Welcome to stack overflow! Unfortunately, your problem statement isn't clear. "either not functioning as i want to or it is giving me an syntax error"-Please describe how the behavior is different, and provide the full traceback of the error you're receiving On the surface, it looks like you may have either an indentation problem or an unindented line breaking the connection between your if and your elif — G. Anderson, Aug 29 '19 at 18:44
Your code snippet is invalid (broken indentation) so no one can make sense of it. Please edit your question with a _proper_ [mcve]. — bruno desthuilliers, Sep 19 '19 at 12:50

Andy Jazz · Answer 1 · 2019-09-19T15:24:27.153

You have to indent the lines of you code according to Python rules.

So you need to use 4 spaces per indentation level – look at PEP 8.

import nuke

selNodes = nuke.selectedNodes()
list = []

for node in selNodes:
    n = node['ypos'].value()
    list.append(n)

def alignY():

    if len(selNodes) > 1:
        total = sum(list)
        average = total / len(selNodes)

        for node in selNodes:
            n = node['ypos'].setValue(average)
            firstNodePostion = list[0]

    elif average == firstNodePostion:
        nuke.message("Nodes already Aligned")

    else:
        nuke.message("Select Two or more Nodes")

alignY()

Now alignY() method works as expected.

score 0 · Answer 2 · answered Aug 29 '19 at 18:47

0

Your problem is that you have a statement that is sitting between the if and the elif, which can cause a syntax error.

It's hard to tell though, because you have not provided the exact error message, but from a syntactical point, there shouldn't be another statement separating the if and the elif.

answered Aug 29 '19 at 18:47

alex067

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The problem is actually that the code snippet the OP posted is broken (invalid syntax) so we can NOT know where the issue really is - and thus should not even try to answer the question since it can only be a wild guess (at best). – bruno desthuilliers Sep 19 '19 at 12:49

The Foundry Nuke – Issues with `elif` and `else` statements

2 Answers2