When I execute:
I get a
Null at the last line of the result.
This is an example shown in the documentation of
What is the
Null? Why does it appear?
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Mathematica is a term rewriting system. It works by taking an input expression and transforming it according to some rules to produce an output expression. The implication is that every evaluation will have a result. For every input there is an output.
Null is simply the expression used to represent "no result". In StandardForm and OutputForm it is not printed. Thus when the result is
Null, it is usually simply not shown. Try evaluating
Null alone and it will appear that there is no output. In InputForm however it is shown as "
Null". You can also try
Clarification: When you evaluate
Print[x] // InputForm,
Null is not "the last line of the result". It is the only result. There is always precisely one result.
x you see is not a result of the evaluation. It simply happens to be shown as a side effect of evaluating