Table of Contents

Functions

Built-in Functions

The framework includes a set of already math implemented functions.

Name Description Usage Result
Abs Returns the absolute value of a specified number. Abs(-1) 1d
Acos Returns the angle whose cosine is the specified number. Acos(1) 0d
Asin Returns the angle whose sine is the specified number. Asin(0) 0d
Atan Returns the angle whose tangent is the specified number. Atan(0) 0d
Ceiling Returns the smallest integer greater than or equal to the specified number. Ceiling(1.5) 2d
Cos Returns the cosine of the specified angle. Cos(0) 1d
Exp Returns e raised to the specified power. Exp(0) 1d
Floor Returns the largest integer less than or equal to the specified number. Floor(1.5) 1d
IEEERemainder Returns the remainder resulting from the division of a specified number by another specified number. IEEERemainder(3, 2) -1d
Ln Returns the natural logarithm of a specified number. Ln(1) 0d
Log Returns the logarithm of a specified number. Log(1, 10) 0d
Log10 Returns the base 10 logarithm of a specified number. Log10(1) 0d
Max Returns the larger of two specified numbers. Max(1, 2) 2
Min Returns the smaller of two numbers. Min(1, 2) 1
Pow Returns a specified number raised to the specified power. Pow(3, 2) 9d
Round Rounds a value to the nearest integer or specified number of decimal places. The midpoint behavior can be changed with ExpressionEvaluationOptions.Math.MidpointRounding. Round(3.222, 2) 3.22d
Sign Returns a value indicating the sign of a number. Sign(-10) -1
Sin Returns the sine of the specified angle. Sin(0) 0d
Sqrt Returns the square root of a specified number. Sqrt(4) 2d
Tan Returns the tangent of the specified angle. Tan(0) 0d
Truncate Calculates the integral part of a number. Truncate(1.7) 1

It also includes other general purpose ones.

Name Description Usage Result
in Returns whether an element is in a set of values. in(1 + 1, 1, 2, 3) true
if Returns a value based on a condition. if(3 % 2 = 1, 'value is true', 'value is false') 'value is true'
ifs Returns a value based on evaluating a number of conditions, returning a default if none are true. ifs(foo > 50, "bar", foo > 75, "baz", "quux") if foo is between 50 and 75 "bar", foo greater than 75 "baz", otherwise "quux"
escapeLike Escapes %, _, and \ so a value is matched literally in a LIKE pattern. escapeLike('100%') '100%'

By default, the comma is used as argument separator, but you can change it using <xref:NCalc.Parser.ArgumentSeparator>. You can specify multiple separators.

var configuration = new ExpressionConfiguration
{
    Parsing = new LogicalExpressionParserOptions
    {
        ArgumentSeparator = ArgumentSeparator.Comma | ArgumentSeparator.Semicolon
    }
};

Configure FloatingPointNumberType and IntegerNumberType to control how math functions coerce string numbers. The floating-point option also selects decimal precision for the applicable math functions.

Custom Functions

Custom functions are created using the ExpressionFunction delegate. The argument list is exposed as FunctionData, which lets you evaluate parameters lazily when needed.

expression.Functions["SecretOperation"] = args => {
    return (int)args[0].Evaluate() + (int)args[1].Evaluate();
};

Using Event Handlers

You can also use event handlers to handle functions.

expression.EvaluateFunction += delegate(string name, FunctionEventArgs args)
{
    if (name == "SecretOperation")
        args.Result = (int)args.Parameters.Evaluate(0) + (int)args.Parameters.Evaluate(1);
};

Case Sensitivity

See case_sensitivity for more info.

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