Hm, I think if you just did:
 
SUBSTITUTE(Label, "[art medium]", Medium) & "," & SUBSTITUTE(Label, "[main objects]", {Main objects}) 
That might work fine actually?
Here's an example, and the code I'm using is:
 
SUBSTITUTE(
  Label,
  '[medium]', 
  Medium
) 

                
     
                                    
            Hm, I think if you just did:
 
SUBSTITUTE(Label, "[art medium]", Medium) & "," & SUBSTITUTE(Label, "[main objects]", {Main objects}) 
That might work fine actually?
Here's an example, and the code I'm using is:
 
SUBSTITUTE(
  Label,
  '[medium]', 
  Medium
) 

I think I didn't explain very well the first time around
I have a Single Line Text column with a default the default text :
[art medium], [main objects], [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist]The words between the brackets is placeholders for values coming from other columns.
As mentioned I tried this
IF(Medium = BLANK(),
 SUBSTITUTE(Label, "[art medium], ", "" ),
 SUBSTITUTE(Label, "[art medium]", Medium)
) &
IF({Main objects}=BLANK(),
 SUBSTITUTE(Label, "[main objects], ", "" ),
 SUBSTITUTE(Label, "[main objects]", {Main objects})
)
 I tested it with the following:

But as I discovered it gives the following output:
digital art, [main objects], [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist][art medium], House, [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist]
Whereas I was hoping for something more:
digital art, House, [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist]
I definitely makes sense this is happening, SUBSTITUTE(Label, "[art medium]", Medium) only replaces the [art medium] bit and does not take the others out. But I'm not sure if there is another way around this?
 
 
                
     
                                    
            I think I didn't explain very well the first time around
I have a Single Line Text column with a default the default text :
[art medium], [main objects], [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist]The words between the brackets is placeholders for values coming from other columns.
As mentioned I tried this
IF(Medium = BLANK(),
 SUBSTITUTE(Label, "[art medium], ", "" ),
 SUBSTITUTE(Label, "[art medium]", Medium)
) &
IF({Main objects}=BLANK(),
 SUBSTITUTE(Label, "[main objects], ", "" ),
 SUBSTITUTE(Label, "[main objects]", {Main objects})
)
 I tested it with the following:

But as I discovered it gives the following output:
digital art, [main objects], [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist][art medium], House, [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist]
Whereas I was hoping for something more:
digital art, House, [attribute], [expression], [key light], [detailing], [camera shot], [media], [engine], [artist]
I definitely makes sense this is happening, SUBSTITUTE(Label, "[art medium]", Medium) only replaces the [art medium] bit and does not take the others out. But I'm not sure if there is another way around this?
 
 
Ah, right, so sorry, I understand now
 
Could you try:
SUBSTITUTE(
  SUBSTITUTE(
    Label, 
    "[main objects]", 
    {Main Objects}
  ), 
  "[art medium]", 
  {Art Medium}
)Which will give you:

Thank you for your patience explaining this
 
                
     
                                    
            Ah, right, so sorry, I understand now
 
Could you try:
SUBSTITUTE(
  SUBSTITUTE(
    Label, 
    "[main objects]", 
    {Main Objects}
  ), 
  "[art medium]", 
  {Art Medium}
)Which will give you:

Thank you for your patience explaining this
 
Well played, with the nesting of the substitue()... It works.
Thank you for taking me through it.