If Command
From GeoGebra Manual
- If[ <Condition>, <Object> ]
- Yields a copy of the object if the condition evaluates to true, and an undefined object if it evaluates to false.
- If[ <Condition>, <Object a>, <Object b> ]
- Yields a copy of object a if the condition evaluates to true, and a copy of object b if it evaluates to false.
Warning: | Both objects must be of the same type. |
Conditional Functions
The If command can be used to create conditional functions. Such conditional functions may be used as arguments in any command that takes a function argument, such as Derivative, Integral, and Intersect.
{{Examples|1=
f(x) = If[x < 3, sin(x), x^2]
yields a piecewise function that equals sin(x) for x < 3 and x2 for x ≥ 3f(x) = If[0 <= x <= 3, sin(x) ]
yields a function that equals sin(x) for x between 0 and 3 (and undefined otherwise)
Note: See section: Boolean values for the symbols used in conditional statements.
Note: Derivative of If[condition, f(x), g(x)] gives If[condition, f'(x), g'(x)]. It does not do any evaluation of limits at the critical points.
If Command in Scripting
If command can be used in scripts to perform different actions under certain conditions.
Example: Let n be a number, and A a point. The command
If[Mod[n, 7] == 0, SetCoords[A, n, 0], SetCoords[A, n, 1]]
modifies the coordinates of point A according to the given condition. In this case it would be easier to use SetCoords[A, n, If[Mod[n, 7] == 0,0,1]]
.Note that arguments of If must be Objects or Scripting Commands, not assignments. Syntax b=If[a>1,2,3]
is correct, but b=2 or b=3 would not be accepted as parameters of If.