IIF

The _IIF pseudo-function is a conditional operator-like feature allowing conditional evaluations with short-circuiting behavior.

Syntax

result = _IIF(expression, truePart, falsePart)

Parameters

• expression is a condition that evaluates to a logical value (true or false).
• truePart is the value or expression returned when expression evaluates to true.
• falsePart is the value or expression returned when expression evaluates to false.

Description

• The _IIF function provides a way to perform conditional evaluations, similar to the ternary operator in C (condition ? truePart : falsePart).
• It ensures short-circuiting, meaning only the relevant branch (truePart or falsePart) is evaluated based on the condition.
• Since only the truePart or falsePart is evaluated, it ensures optimal performance and avoids unnecessary computation.
• The return type is determined by the type of truePart.
• Mixing STRING with other data types in truePart and falsePart is not allowed.
• It allows inline evaluations, improving readability, and reducing the need for verbose IF...THEN...ELSE structures.
• A compiler error is thrown if expression cannot be evaluated as a boolean.

Availability

• 

  none

• 

  v4.0.0

• 
• 

  yes

• 

  yes

• 

  yes

Examples

Example 1

Basic conditional evaluation.

DIM userInput AS INTEGER DIM result AS STRING PRINT "Enter a number:" INPUT userInput result = _IIF(userInput MOD 2 = 0, "Even", "Odd") PRINT "The number is "; result

Enter a number: 5 The number is Odd

Example 2

Using numeric expressions.

DIM x AS INTEGER, y AS INTEGER DIM max AS INTEGER PRINT "Enter the first number:" INPUT x PRINT "Enter the second number:" INPUT y max = _IIF(x > y, x, y) PRINT "The larger number is: "; max

Enter the first number: 10 Enter the second number: 20 The larger number is: 20

Example 3

Preventing unnecessary evaluation.

DIM a AS INTEGER, b AS SINGLE PRINT "Enter a non-zero number:" INPUT a b = _IIF(a <> 0, 100 / a, 0) ' Avoids division by zero when a = 0 PRINT "Result: "; b

Enter a non-zero number: 0 Result: 0

See also

• IF...THEN
• SELECT CASE
• _NEGATE, _ANDALSO, _ORELSE
• Boolean (numerical comparisons return a true or false value)
• Keyword Reference - Alphabetical
• Keyword Reference - By usage

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