How to copy a dict and modify it in one line of code

Question

Very often I need to create dicts that differ one from another by an item or two. Here is what I usually do:

setup1 = {\'param1\': val1, 
            \'param         


        

Answer 1

setup2 = dict(setup1.items() + {'param1': val10, 'param2': val20}.items())

This way if new keys do not exist in setup1 they get added, otherwise they replace the old key/value pairs.