UnboundLocalError: local variable 'readlgt' referenced before assignment

Question

I am using the Foundry Nuke, and I bump into this question:

Here is my program:

def testing(*args):
    for a in nuke.allNodes('Read'):

        if 'lighting' in a ['name'].value():                        
            readlgt = a


        if 'GI' in a['name'].value():
    #        global readGI
            readGI = a

            mergelgt = nuke.nodes.Merge2(operation='plus')      
            mergelgt.connectInput(0, readlgt)
            mergelgt.connectInput(1, readGI)

testing()

Answer 1

Try this:

import nuke

readlgt = nuke.nodes.Read(file="~/Desktop/file1.##.exr", name="readlgt")
readGI = nuke.nodes.Read(file="~/Desktop/file2.##.exr", name="readGI")

def testing():
    for a in nuke.allNodes('Read'):
        if 'lighting' in a['name'].value():                        
            a = readlgt

        if 'GI' in a['name'].value():
            a = readGI

            mergelgt = nuke.nodes.Merge2(operation='plus')

            for these in nuke.allNodes():
                these.setSelected(True)     

                mergelgt.setInput(0, readlgt)
                mergelgt.setInput(1, readGI)

testing()