Expression Operators

TestStand 2017 Help

Edition Date: November 2017

Part Number: 370052W-01

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Operator Class Operators in Symbol Form
Arithmetic The arithmetic symbols include the following items: +, -, *, /, MOD, %, ++, and --.
Assignment The assignment symbols include the following items: =, +=, -=, *=, /=, %=, ^=, &=, and |=.

The equal operator evaluates the expression on the right side of the operator and sets the operand on the left side of the operator to the result. When operating on container properties, the hierarchy of subproperty names on the left and right side must match. For each property value, the assignment converts between different data types whenever possible, for example, numeric to string.
Bitwise The bitwise symbols include the following items: AND, OR, NOT, XOR, &, |, ~, ^ , >>, and <<.
Comparison The comparison symbols include the following items: ==, !=, <>, >, >=, <, and <=. Floating-point comparisons use 14 digits of precision.

Comparison operators work on string, numeric, and Boolean values. If one operand is a string and another is a numeric, the operator converts the string to a numeric value. If both operands are strings, the comparison is case-insensitive. If both operands are non-zero floating-point numeric values, the comparison uses 14 digits of precision. TestStand treats NAN and IND as equivalent in expression comparisons.
Logical The logical symbols include the following items: &&, ||, and !.
Other Some additional operators include the following items:
() Parentheses—Alter evaluation order.
. Dot—Property field separator.
.. Double Dot—Specify a range of indexes in array subscripts. This operator indexes multiple elements in the array and returns a subarray. The operand on each side of the range operator must evaluate to a numeric value, such as array[1..3].
[] Brackets—Array subscript
Note  The operand for an array subscript must evaluate to a numeric value, unless the array contains step or sequence elements. For arrays of step or sequence elements, the subscript can evaluate to a string value that contains the name of a step or sequence element in the array, such as RunState.Sequence.Main["MyGoto"].

You can use the double dot operator (..) within the [] operator to index multiple elements in the array and return a subarray. For example, the expression array[1..3][2] returns the elements at indexes [1][2], [2][2], and [3][2] in a new subarray.
, Comma—Expression separator or terminator.
?: Conditional—Given a Boolean value, chooses one of two other expressions to evaluate

Usage: booleanValue ? expr1 : expr2

{} Array constant.
// Single line comment (C++).
Single line comment (Basic).
/* */ Comment (C/C++).
& Get Reference—Returns a Reference that refers to the operand.
* Dereference—Returns the object to which the Reference operand refers. The Reference must refer to an object that supports the TestStand PropertyObject interface.
-> Dereference and access field—Returns the specified subproperty of the object to which the Reference operand refers. The Reference must refer to an object that supports the TestStand PropertyObject interface.
Constants The formats for the different types of constants include the following items:
1.23e-4 Floating point
1234 Integer
0x1234efa9 Hexadecimal integer
0b11011011 Binary number
1234i64 64-bit integer constant
1234ui64 64-bit unsigned integer constant
True Boolean
False Boolean
"1234wxyz" String
@"file path" Unescaped string, such as @"C:\Windows\temp"
Nothing Empty ActiveX reference
NAN Not a number
IND Indeterminate number
INF Infinite number
PI PI constant (3.141592...)
tsRed Color constant
Note Note  TestStand declares some special constant values that are similar to values used in other environments or used infrequently.

See Also

Levels of Precedence in Operators

Special Constant Values

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