1. About MathEval.NET

MathEval.NET is a mathematical expressions evaluator library written in C#. Allows to evaluate mathematical, boolean, string and datetime expressions Code is written in pure C#, run on the fly. We don't use any third party libraries or packages.

This respository forks from: https://github.com/matheval/expression-evaluator-c-sharp And make many changes:

Reconstruct solution, eg. refolder, csharp-like renaming, simply, and more readable.
Support more DateTime functions, eg: date, now, year, weekday, adddays...
Support more operator, eg: ! !=
Support more text function, eg: like
Support regist custom function.

[TOC]

2. Installation

Using Package Manager

PM> Install-Package MathEval.NET -Version 4.5.0.0

3. Supported operators, contants, functions

3.1 Supported Operators

Operator	Description
+	Additive / Unary plus / Concatenate string / Datetime addition
-	Subtraction / Unary minus / Datetime subtraction
*	Multiplication , can be omitted in front of an open bracket
/	Division
%	Remainder (Modulo)
^	Power
&	Concatenate string
!	Not operator for boolean
>	Greater
>=	Greater equal
<	Less
<=	Less equal
<>	Not equal
!=	Not equal

3.2 Supported Constants

Constant	Description
E	The value of e
PI	The value of PI
TRUE	The boolean true value
FALSE	The boolean false value
NULL	The null value

3.3 Supported conditional statements

Conditional statement	Description
IF(condition, valueIfTrue, valueIfFalse)	Example: `IF(2>1,"Pass","Fail")`
SWITCH(expression, val1, result1, [val2,result2], …, [default])	Example: `SWITCH(3+2,5,"Apple",7,"Mango",3,"Good","N/A")`

3.4 Supported logical functions

Function	Description
AND(logical1, [logical2], …)	Determine if all conditions are TRUE
OR(logical1, [logical2], …)	Determine if any conditions in a test are TRUE
NOT(logical)	To confirm one value is not equal to another
XOR(logical1, [logical2], …)	Exclusive OR function

3.5 Supported math functions

Function	Description
MOD(number, divisor)	Get remainder of two given numbers after division operator.
ROUND(number, num_digits)	Returns the rounded approximation of given number using half-even rounding mode ( you can change to another rounding mode)
FLOOR(number, significance)	Rounds a given number towards zero to the nearest multiple of a specified significance
CEILING(number, significance)	Rounds a given number away from zero, to the nearest multiple of a given number
POWER(number, power)	Returns the result of a number raised to a given power
RAND()	Produces a random number between 0 and 1
SQRT(number)	Returns the correctly rounded positive square root of given number
LN(number)	Returns the natural logarithm (base e) of given number
LOG10(number)	Returns the logarithm (base 10) of given number
EXP(number)	Returns e raised to the power of given number
ABS(number)	Returns the absolute value of given number
FACT(number)	Returns the factorial of a given number
INT(number)	Returns the Integer value of given number

3.6 Supported math trigonomatric functions

Function	Description
PI()	Return value of Pi
SIN(number)	Returns the trigonometric sine of the angle given in radians
SINH(number)	Returns the hyperbolic sine of a number
ASIN(number)	Returns the arc sine of an angle, in the range of -pi/2 through pi/2
COS(number)	Returns the trigonometric cos of the angle given in radians
COSH(number)	Returns the hyperbolic cos of a number
ACOS(number)	Returns the arc cosine of an angle, in the range of 0.0 through pi
TAN(number)	Returns the tangent of the angle given in radians
TANH(number)	Returns the hyperbolic tangent of a number
ATAN(number)	Returns the arc tangent of an angle given in radians
ATAN2(x_number, y_number)	Returns the arctangent from x- and y-coordinates
COT(number)	Returns the cotangent of an angle given in radians
COTH(number)	Returns the hyperbolic cotangent of a number
SEC(number)	Returns the secant of an angle given in radians
CSC(number)	Returns the cosecant of an angle given in radians
RADIANS(degrees)	Convert degrees to radians
DEGREES(radians)	Convert radians to degrees

3.7 Supported math statistic functions

Function	Description
COUNT(number1, [number2],…)	Return count of numbers supplied
SUM(number1, [number2],…)	Return sum of numbers supplied
AVERAGE(number1, [number2],…)	Return average of numbers supplied
MIN(number1, [number2],…)	Return the smallest value from the numbers supplied
MAX(number1, [number2],…)	Return the biggest value from the numbers supplied

3.8 Supported text functions

Function	Description
LEFT(text, num_chars)	Extracts a given number of characters from the left side of a supplied text string
RIGHT(text, num_chars)	Extracts a given number of characters from the right side of a supplied text string
MID(text, start_num, num_chars)	Extracts a given number of characters from the middle of a supplied text string
REVERSE(text)	Reverse a string
LOWER(text)	Converts all letters in the specified string to lowercase
UPPER(text)	Converts all letters in the specified string to uppercase
PROPER(text)	Capitalizes words given text string
TRIM(text)	Removes extra spaces from text
TEXT(value, [format_text])	Convert a numeric value into a text string. You can use the TEXT function to embed formatted numbers inside text
REPLACE(old_text, start_num, num_chars, new_text)	Replaces characters specified by location in a given text string with another text string
SUBSTITUTE(text, old_text, new_text)	Replaces a set of characters with another
FIND(find_text, within_text, [start_num])	Returns the location of a substring in a string (case sensitive)
SEARCH(find_text, within_text, [start_num])	Returns the location of a substring in a string (case insensitive)
CONCAT(text1, text2, text3,…)	Combines the text from multiple strings
REPT(text, repeat_time)	Repeats characters a given number of times
------------------------------------------------------	----------------------------------------------------------
ISBLANK(text)	Returns TRUE when a given string is null or empty, otherwise return FALSE
ISNUMBER(text)	Check if a value is a number
LEN(text)	Returns the length of a string/ text
CHAR(ascii-code)	Return character from ascii code
CODE(char)	Returns a ascii code of a character
VALUE(text)	Convert numbers stored as text to numbers
LIKE(text, sqlpattern)	Returns TRUE when a given string match the sqlpattern string(support _*%). eg: like("Abcd", "_bc%")

Text() Example:

Function	Description
TEXT(123)	123
TEXT(DATEVALUE("2021-01-23"),"dd-MM-yyyy")	23-01-2021
TEXT(2.61,"hh:mm")	14:38
TEXT(2.61,"[hh]")	62
TEXT(2.61,"hh-mm-ss")	14-38-24
TEXT(DATEVALUE("2021-01-03")-DATEVALUE("2021-01-01"),"[h]")	48
TEXT(TIME(12,00,00)-TIME(10,30,10),"hh hours and mm minutes and ss seconds")	01 hours and 29 minutes and 50 seconds

3.9 Supported DateTime functions

Function	Description
Today()	Today()
Now()	Now()
Date(.)	Date('2024-01-01 12:00')
Year(.)	Year('2024-01-01 12:00')
Month(.)	Month(Today())
Day(.)	Day(Today())
Hour(.)	Hour(Today())
Minute(.)	Minute(Today())
Second(.)	Second(Today())
Weekday(.)	Weekday(Today())
Age(.)	Age(Today())
AddYears(..)	AddYears(Today(), 1)
AddMonths(..)	AddMonths(Today(), 1)
AddDays(..)	AddDays(Today(), 1)
AddHours(..)	AddHours(Today(), 1)
AddMinutes(..)	AddMinutes(Today(), 1)
AddSeconds(..)	AddSeconds(Today(), 1)
AddDate(.......)	AddDate(Today(), 1,0,0,0,0,0)

DateTime functions examples:

var expr = new Expression();
Assert.AreEqual(DateTime.Parse("2020-01-01"),           expr.SetFormular("Date('2020-01-01')").Eval<DateTime>());
Assert.AreEqual(DateTime.Today,                         expr.SetFormular("Today()").Eval<DateTime>());
Assert.AreEqual(DateTime.Now.Day,                       expr.SetFormular("Now()").Eval<DateTime>().Day);
//											            
Assert.AreEqual(DateTime.Today.Year,                    expr.SetFormular("Year(Today())").Eval<int>());
Assert.AreEqual(DateTime.Today.Month,                   expr.SetFormular("Month(Today())").Eval<int>());
Assert.AreEqual(DateTime.Today.Day,                     expr.SetFormular("Day(Today())").Eval<int>());
Assert.AreEqual(DateTime.Today.Hour,                    expr.SetFormular("Hour(Today())").Eval<int>());
Assert.AreEqual(DateTime.Today.Minute,                  expr.SetFormular("Minute(Today())").Eval<int>());
Assert.AreEqual(DateTime.Today.Second,                  expr.SetFormular("Second(Today())").Eval<int>());
Assert.AreEqual(0,                                      expr.SetFormular("Age(Today())").Eval<int>());
Assert.AreEqual(DateTime.Today.DayOfWeek,               expr.SetFormular("Weekday(Today())").Eval<DayOfWeek>());
Assert.AreEqual(DateTime.Today.AddYears(1),             expr.SetFormular("AddYears(Today(), 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Today.AddMonths(1),            expr.SetFormular("AddMonths(Today(), 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Today.AddDays(1),              expr.SetFormular("AddDays(Today(), 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Today.AddHours(1),             expr.SetFormular("AddHours(Today(), 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Today.AddMinutes(1),           expr.SetFormular("AddMinutes(Today(), 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Today.AddSeconds(1),           expr.SetFormular("AddSeconds(Today(), 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Today.AddYears(1),             expr.SetFormular("AddDate(Today(), 1,0,0,0,0,0)").Eval<DateTime>());
//
Assert.AreEqual(2020,                                   expr.SetFormular("Year('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(1,                                      expr.SetFormular("Month('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(1,                                      expr.SetFormular("Day('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(12,                                     expr.SetFormular("Hour('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(0,                                      expr.SetFormular("Minute('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(0,                                      expr.SetFormular("Second('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(DateTime.Now.Year-2020,                 expr.SetFormular("Age('2020-01-01 12:00')").Eval<int>());
Assert.AreEqual(DayOfWeek.Wednesday,                    expr.SetFormular("Weekday('2020-01-01 12:00')").Eval<DayOfWeek>());
Assert.AreEqual(DateTime.Parse("2021-01-01 12:00:00"),  expr.SetFormular("AddYears('2020-01-01 12:00', 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Parse("2020-02-01 12:00:00"),  expr.SetFormular("AddMonths('2020-01-01 12:00', 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Parse("2020-01-02 12:00:00"),  expr.SetFormular("AddDays('2020-01-01 12:00', 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Parse("2020-01-01 13:00:00"),  expr.SetFormular("AddHours('2020-01-01 12:00', 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Parse("2020-01-01 12:01:00"),  expr.SetFormular("AddMinutes('2020-01-01 12:00', 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Parse("2020-01-01 12:00:01"),  expr.SetFormular("AddSeconds('2020-01-01 12:00', 1)").Eval<DateTime>());
Assert.AreEqual(DateTime.Parse("2021-01-01 12:00:00"),  expr.SetFormular("AddDate('2020-01-01 12:00', 1,0,0,0,0,0)").Eval<DateTime>());

4. Custom functions

MathEval.NET support custom functions:

Create class to implements IFunction.
Regist this class to Expresson object using RegistFunction() or RegistFunctions().
OK, run eval().

Examples:

using System;
using System.Collections.Generic;
using Org.MathEval.Common.Functions;
using static Org.MathEval.Common;
public class DateFunctions : IFunction
{
    public List<FunctionDef> GetDefs()
    {
        return new List<FunctionDef> {
            new FunctionDef("now",        typeof(DateTime), 0, null),
            new FunctionDef("year",       typeof(int),      1, typeof(DateTime)),
            new FunctionDef("AddYears",   typeof(DateTime), 2, typeof(DateTime), typeof(int)),
        };
    }
    public object Execute(List<object> args, ExpressionContext dc, string funcName = "")
    {
        var name = funcName.ToLower();
        switch (name)
        {
            case "now":        return DateTime.Now;
            case "year":       return ToDateTime(args[0]).Year;
            case "addyears":   return ToDateTime(args[0]).AddYears(ToInt(args[1]));
        }
        return DateTime.Now;
    }
}

// regist and use this functions
var expression = new Expression().RegistFunction(new DateFunctions());  // regist date functions
var dt = expression.SetFormula("Now()").Eval<DateTime>();               // eval now() function

5. Usage examples

5.1 Basic evaluator

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		var expression = new Expression("(a + b) / 2 ");
		expression.Bind("a", 3);
		expression.Bind("b",5);
		Object value = expression.Eval();
		Console.WriteLine("Result: "+value); //Result: 4
		
	}
}

5.2 Conditional statements

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		Expression expression = new Expression("IF(time>8, (HOUR_SALARY*8) + (HOUR_SALARY*1.25*(time-8)), HOUR_SALARY*time)");
		//bind variable
		expression.Bind("HOUR_SALARY", 10);
		expression.Bind("time", 9);
		//eval
		Decimal salary = expression.Eval<Decimal>();	
		Console.WriteLine(salary); //return 92.5
	}
}

5.3 Validate expression

Expression expression = new Expression("SUM(1,2,3) + true");
List<String> errors = expression.GetError(); 
if(errors.Count > 0)
{
  foreach(String error in errors)
  {
  	Console.WriteLine(error);
  }
}

5.4 Min, max, sum, avg

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		Expression expr = new Expression("MIN(2,3,16)");
		int min = expr.Eval<int>(); 
		Console.WriteLine(min);// return 2 (min)
		
		expr.SetFomular("Max(2,3,16)");
		int max = expr.Eval<int>(); 
		Console.WriteLine(max);// return 16 (max)
		
		expr.SetFomular("Sum(2,3,16)");
		decimal sum = expr.Eval<decimal>(); 
		Console.WriteLine(sum);// return 21	(sum)
		
		expr.SetFomular("average(2,3,16)");
		decimal average = expr.Eval<decimal>(); 
		Console.WriteLine(average);// return 7 (average)	
	}
}

5.5 Round, floor, ceiling

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		Expression expr = new Expression("ROUND(2.149, 1)");
		Object value = expr.Eval<Decimal>(); 
		Console.WriteLine("ROUND(2.149, 1) = "+value); //return 2.1
		
		expr = new Expression("FLOOR(2.149)");
		value = expr.Eval(); 
		Console.WriteLine("FLOOR(2.149) = "+value); //return 2	
		
		expr = new Expression("FLOOR(3.7,2)");
		value = expr.Eval(); 
		Console.WriteLine("FLOOR(3.7,2) = "+value);	//return 2
		
		expr = new Expression("CEILING(2.149)");
		value = expr.Eval(); 
		Console.WriteLine("CEILING(2.149) = "+value); //return 3
		
		expr = new Expression("CEILING(1.5, 0.1)");
		value = expr.Eval(); 
		Console.WriteLine("CEILING(1.5, 0.1) = "+value); //return 1.5	
	}
}

5.6 Trigonometry

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		Expression expr = new Expression("tan(a)^3-((3*sin(a)-sin(3*a))/(3*cos(a)+cos(3*a)))");
		Decimal value = expr.Bind("a", Math.PI/6).Eval<Decimal>(); 
		Console.WriteLine(value); //return 0		
	}
}

5.7 Deal with string

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		Expression taxExpr = new Expression("IF(LOWER(TAX_CODE)='vat',amount*10/100,IF(LOWER(TAX_CODE)='gst',amount*15/100,0))");
		taxExpr.Bind("TAX_CODE","GST");
		taxExpr.Bind("amount", 5005m);
		Decimal value = taxExpr.Eval<Decimal>();
		Console.WriteLine(value);
	}
}

5.8 Concatenate strings

using System;
using org.matheval;
					
public class Program
{
	public static void Main()
	{
		Expression expr = new Expression("CONCAT('The United States of ', 'America')");
		String value = expr.Eval<String>();	
		Console.WriteLine(value);//The United States of America	
	}
}

6.License

MIT license

Name		Name	Last commit message	Last commit date
Latest commit History 17 Commits
MathEval		MathEval
MathEvalTests		MathEvalTests
.gitignore		.gitignore
LICENSE		LICENSE
MathEval.sln		MathEval.sln
README.md		README.md

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Repository files navigation

1. About MathEval.NET

2. Installation

3. Supported operators, contants, functions

3.1 Supported Operators

3.2 Supported Constants

3.3 Supported conditional statements

3.4 Supported logical functions

3.5 Supported math functions

3.6 Supported math trigonomatric functions

3.7 Supported math statistic functions

3.8 Supported text functions

3.9 Supported DateTime functions

4. Custom functions

5. Usage examples

5.1 Basic evaluator

5.2 Conditional statements

5.3 Validate expression

5.4 Min, max, sum, avg

5.5 Round, floor, ceiling

5.6 Trigonometry

5.7 Deal with string

5.8 Concatenate strings

6.License

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Repository files navigation

1. About MathEval.NET

2. Installation

3. Supported operators, contants, functions

3.1 Supported Operators

3.2 Supported Constants

3.3 Supported conditional statements

3.4 Supported logical functions

3.5 Supported math functions

3.6 Supported math trigonomatric functions

3.7 Supported math statistic functions

3.8 Supported text functions

3.9 Supported DateTime functions

4. Custom functions

5. Usage examples

5.1 Basic evaluator

5.2 Conditional statements

5.3 Validate expression

5.4 Min, max, sum, avg

5.5 Round, floor, ceiling

5.6 Trigonometry

5.7 Deal with string

5.8 Concatenate strings

6.License

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