It stands for python fast evaluator. It evaluates mathematical (arithmetic and logical) expressions in python.
I needed to evaluate mathematical expressions in python but very fast. There are many python libraries that evaluate a string but they take few miliseconds to calculate the result. For my use case, few miliseconds was detrimental.
Untill I found this thread:
https://stackoverflow.com/questions/15884727/recursive-boolean-evaluation
This inspired me to work on this project. Currently the expression should be in a certain format to be parsed. for example:
1+2 should be entered as ADD(1,2) and
3x(1+2) as MUL(3,ADD(1,2)) and
3x(1+3)-4x(5/3) as SUB(MUL(3,ADD(1,3),MUL(4,DIV(5,3))) and etc.
This is the list of supported operations at the moment:
Arithmetic operations:
(+) : ADD example : 1+2 as ADD(1,2)
(-) : SUB example : 1-2 as SUB(1,2)
(x) : MUL example : 1X2 as MUL(1,2)
(/) : DIV example : 1/2 as DIV(1,2)
(^) : POW example : 1^2 as POW(1,2)
Comparisions:
(> ) : GT example : 1>2 as GT(1,2)
(>=) : GE example : 1>=2 as GE(1,2)
(< ) : LT example : 1<2 as LT(1,2)
(<=) : LE example : 1<=2 as LE(1,2)
(==) : EQ example : 1==2 as EQ(1,2)
(!=) : NE example : 1!=2 as NE(1,2)
Boolean operations:
& : AND example : b1 & b2 as AND(b1,b2)
| : OR example : b1 | b2 as OR(b1,b2)
! : NOT example : !b as NOT(b)
Trigonometry:
Sine (argument in raidian): SIN example : SIN(0)
Sine (argument in degree): SIND example : SIND(30)
Cosine (argument in raidian): COS example : COS(0)
Cosine (argument in degree): COSD example : COSD(30)
Tangent (argument in raidian): TAN example : TAN(0)
Tangent (argument in degree): TAND example : TAND(30)
Generic:
Absoulte vlaue: ABS example : ABS(-10)
Square root: SQRT example : SQRT(4)
The following errors are detected:
1- Devision by zero
2- Square root with negative argument