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An expression can be created with operators and functions.
Operators
Expressions can be combined using operators. Each operator has a precedence. Here is the list of these expressions’ priorities.
1. primary
2. unary
3. power
4. multiplicative
5. additive
6. relational
7. logical
Logical
These operators can do some logical comparison between other expressions:
or, ||
and, &&
The “and” operator has more priority than the “or”, thus in the example above, “false and true” is evaluated first.
Relational
=, ==, !=, <>
<, <=, >, >=
Additive
+, –
Multiplicative
*, /, %
Bitwise
& (bitwise and), | (bitwise or), ^(bitwise xor), << (left shift), >>(right shift)
Unary
!, not, -, ~ (bitwise not)
Primary
(, )
Functions
The following table describes standard functions:
| Name |
Description
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Usage |
Result |
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Abs
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Returns the absolute value of a specified number
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Abs(-1)
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1
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Acos
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Returns the angle whose cosine is the specified number
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Acos(1)
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0
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Asin
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Returns the angle whose sine is the specified number
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Asin(0)
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0
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Atan
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Returns the angle whose tangent is the specified number
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Atan(0)
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0
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Ceiling
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Returns the smallest integer greater than or equal to the specified number
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Ceiling(1.5)
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2
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Cos
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Returns the cosine of the specified angle
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Cos(0)
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1
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Exp
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Returns e raised to the specified power
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Exp(0)
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1
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Floor
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Returns the largest integer less than or equal to the specified number
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Floor(1.5)
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1
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IEEERemainder
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Returns the remainder resulting from the division of a specified number by another specified number
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IEEERemainder (3, 2)
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-1
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Log
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Returns the logarithm of a specified number
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Log(1, 10)
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0
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Log10
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Returns the base 10 logarithm of a specified number
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Log10(1)
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0
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Max
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Returns the larger of two specified numbers
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Max(1, 2)
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2
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Min
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Returns the smaller of two numbers
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Min(1, 2)
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1
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Pow
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Returns a specified number raised to the specified power
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Pow(3, 2)
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9
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Round (available in PcVue 10 SP2, PcVue 11)
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Rounds a value to the nearest integer or specified number of decimal places. The mid number behaviour can be changed by using EvaluateOption.RoundAwayFromZero during construction of the Expression object.
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Round (3.222, 2)
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3.22
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Sign
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Returns a value indicating the sign of a number
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Sign(-10)
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-1
|
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Sin
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Returns the sine of the specified angle
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Sin(0)
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0
|
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Sqrt
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Returns the square root of a specified number
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Sqrt(4)
|
2
|
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Tan
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Returns the tangent of the specified angle
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Tan(0)
|
0
|
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Truncate
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Calculates the integral part of a number
|
Truncate(1.7)
|
1
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It also includes other general purpose ones.
| Name |
Description |
Usage |
Result |
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if
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Returns a value based on a condition
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if(3 % 2 = 1, ‘value is true’, ‘value is false’)
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‘value is true’
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Then, those following functions can be used in an expression:
int StrIndexOf(string String, string StringSeek)
Reports the index of the first occurrence of the string seek in the string parameter.
int StrLastIndexOf(string String, string StringSeek)
Reports the index of the last occurrence of the string seek in the string parameter.
string StrSubstring(string String, int StartIndex)
Returns a substring from the string parameter. The substring starts at the startIndex position.
string StrSubstring(string String, int StartIndex, int Length)
Returns a substring from the string parameter. The substring starts at the startIndex position and has the count length.
string StrRemove(string String, int StartIndex)
In the returning string, deletes all the characters from this string beginning at a specified position and continuing through the last position.
string StrRemove(string String, int StartIndex, int Length)
In the returning string, deletes all the characters from this string beginning at a specified position for count characters.
string StrLeft(String string, int Length)
Returns a string containing the count first character of the string parameter.
string StrRight(string String, int Length)
Returns a string containing the count last character of the string parameter.
string StrTrim(string String)
Returns a string with all leading and trailing white-space characters removed from the string parameter.
string StrTrim(string String, string ParseChars)
Returns a string with all leading and trailing occurrences of a set of characters specified in trimChars removed from the string parameter.
string StrTrimEnd(string String, string ParseChars)
Returns a string with all trailing occurrences of a set of characters specified in trimChars removed from the end of the string parameter.
For example, if the current string is “123abc456xyz789” and trimChars is “123456789”, the TrimEnd method returns “123abc456xyz”.
string StrTrimStart(string String, string ParseChars)
Returns a string with all trailing occurrences of a set of characters specified in trimChars removed from the start of the string parameter.
For example, if the current string is “123abc456xyz789” and trimChars is “123456789”, the TrimStart method returns “abc456xyz789”.
string StrPadLeft(string String, int totalWidth, char paddingChar)
Left-aligns the characters in this instance (string), padding on the left with a specified character (Char) for a specified total length (Count)
string StrPadRight(string String, int totalWidth, char paddingChar)
Right-aligns the characters in this instance (string), padding on the left with a specified character (Char) for a specified total length (Count)
string StrToUpper (string String)
Converts all characters in a string to uppercase
string StrToLower(string String)
Converts all characters in a string to lowercase
string StrReplace(string String, string OldValue, string NewValue)
Replaces all occurrences of a specified String in string parameter, with another specified String.
string StrExtract(string String, char separatorChar, int Pos)
Returns a string that contains the substring of string parameter at the given zero based position (Pos) in string parameter that is delimited by one of the characters (separatorChars)
For example, if the current string is ” My.name.is.John “, separatorChar is “.” and Pos is 1, the StrExtract method returns ” name “.
string StrReverseExtract (string String, char separatorChar, int Pos)
Returns a string that contains the substring of string parameter at reverse position (Pos) in string parameter that is delimited by one of the characters (separatorChars)
For example, if the current string is ” My.name.is.John “, separatorChar is “.” and Pos is 1, the StrExtract method returns ” is “.
int StrCompareMethod (String, StringToCompare)
Compares two specified String objects, ignoring or honoring their case, and returns an integer that indicates their relationship to one another in the sort order.
int StrCompareNoCase Method (String, StringToCompare)
Compares two specified String objects, ignoring their case, and returns an integer that indicates their relationship to one another in the sort order.
bool StrEqualMethod (String, StringToCompare)
Compares two specified String objects, ignoring or honoring their case, and returns a Boolean that indicates their equivalence.
bool StrEqualNoCaseMethod (String, StringToCompare)
Compares two specified String objects, ignoring their case, and returns a Boolean that indicates their equivalence.
Example
Sample project “Expression_AA” attached illustrates use of expressions with operators and functions. In Application Architect as shown below, all the above operators and functions are used in the different parameters of the project.
Download attachments: Expression_AA.7z
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