WolframLang: CompoundExpression and Semicolon
Semicolon in WolframLang, e.g.
a;b
is a short syntax for
CompoundExpression[a,b].
It is used to group several expressions together as one syntactic unit.
It is similar to many language's code block by braces {…}, or lisp's progn.
| Short syntax | FullForm |
expr1;expr2 | CompoundExpression[expr1, expr2] |
expr1; | CompoundExpression[expr1,Null] |
CompoundExpression[expr1, expr2, etc]- (short syntax:
expr1;expr2;etc)
Eval all arguments and return the value of last argument. CompoundExpression
CompoundExpression
is frequently used in
If,
Function,
Module,
or anytime when you need to do several computation as a single expression as one arg to function.
Examples:
If[x,
doTrueExpr1;
doTrueExpr2;
etc,
doFalseExpr1;
doFalseExpr2;
etc
]
[see WolframLang: If Then Else (Conditionals, Branching)]
Function[{vars},
expr1;
expr2;
etc]
[see WolframLang: Define Function]
Module[{vars},
expr1;
expr2;
etc
]
[see WolframLang: Local Variable]
Often,
you'll find it convenient to put a semicolon at end of some expression.
In particular, after assignment.
It has the effect of suppressing output.
For example, x=3 return 3, but x=3; return Null, and Null output is not printed.
