manual:chapter6:stack:cmd

Synopsis

Execute objects on the stack conditionally

Stack Diagram

Input Stack				Output Stack
1	O_true	O_false	→	[O_true]_XEQ
0	O_true	O_false	→	[O_false]_XEQ
Level 3 / Argument 1	Level 2 / Argument 2	Level 1 / Argument 3	→	Level 1

Legend

Legend	Object type
O	Any object
I	Integer number
R	Real number
#	Binary number
Num	Scalar (Integer, Real or Binary number)
Z	Complex number
U	Unit
∡	Angle
A	Symbolic expression
C	Symbolic constant
V	Vector
M	Matrix
S	String
1/0	Any expression evaluating to True or False
G	Grob
F	Font
D	Binary data container
T	Tag object
L	List
cL	Case list
N	Variable name / Identifier
Dir	Directory
pDir	Packed Directory
P	Program
Lib	Library

Type	Function
Parallel list processing	Group 2
Affected by flags	None

Description

The IFTE function tests the object on level 3 of the stack: if the test returns 1 then it XEQtes the object on level 2, otherwise it XEQtes the object on level 1.

IFTE can be used in symbolic expressions to define piecewise functions.

Compatibility

This command is fully compatible with userRPL.

Usage

3:                             1
2:               { 'X' 'Y' 'Z' }
1:                           1_m
……………………………………………………………………………………
IFTE

will result in

1:               { 'X' 'Y' 'Z' }
……………………………………………………………………………………

Related Commands

Stack manipulation 27 5 NEW

Command	Short Description
CLEAR	Remove all objects from the stack
DEPTH	Get the current stack depth
DROP	Remove an object from the stack
DROP2	Remove two objects form the stack
DROPN	Remove N objects from the stack
DUP	Duplicate an object on the stack
DUP2	Duplicate two objects on the stack
DUPDUP	Duplicate the same object twice on the stack
DUPN	Duplicate a group of N objects
NDUPN	Replicate one object N times and return N
NIP	Remove object at level 2 on the stack
OVER	Duplicate object at level 2 on the stack
PICK	Duplicate object at position N on the stack
PICK3	Duplicate object at level 3 on the stack
ROLL	Move object at level N to level 1
ROLLD	Move object from level 1 to level N
ROT	Move object from level 3 to level 1
SWAP	Exchange objects in levels 1 and 2
UNPICK	Move object from level 1 to level N.
UNROT	Move object from level 1 to level 3
IFT	Evaluate objects on the stack conditionally
IFTE	Evaluate objects on the stack conditionally
STKPUSH	Push a snapshot of the current stack on the undo stack	NEW
STKPOP	Pop a stack snapshot from the undo stack	NEW
STKDROP	Drop a snapshot from the undo stack	NEW
STKPICK	Copy snapshot in level N to the current stack	NEW
STKDEPTH	Get the depth of the undo stack	NEW