Math expression evaluation library. It supports most of useful math operations and functions. Expressions can contain variables which can be substituted with ints, floats or numpy.ndarrays.

Example usage

from parser import Parser

parser = Parser("(-b + sqrt(b^2-4a c))/(2a)")

parser.variables_names # {'c', 'a', 'b'}

parser.evaluate({"a": 1, "b": -3, "c": 2}) # 1.0

parser.evaluate({"a": [1, 1, 1], "b": [-5, -6, -9], "c": [6, 9, 20]}) # [2. 3. 4.]

Expression syntax

Expression can contain numbers or variable names with functions applyed to them, separated with operators or united with braces.

Theese are supported:

Functions:

name	math
`abs`	`\\|x\\|`
`acos`	`\cos^{-1}(x)`
`acosh`	`\cosh^{-1}(x)`
`acot`	`\cot^{-1}(x)`
`asin`	`\sin^{-1}(x)`
`asinh`	`\sinh^{-1}(x)`
`atan`	`\tan^{-1}(x)`
`avg`	`\overline x`
`cos`	`\cos(x)`
`cosh`	`\cosh(x)`
`cot`	`\cot(x)`
`exp`	`\exp(x)`
`lg`	`\lg(x)`
`ln`	`\ln(x)`
`log10`	`\log_{10}(x)`
`log2`	`\log_2(x)`
`prod`	`\displaystyle \prod_{i=0}^n x_i`
`sgn`	`sgn(x)`
`sin`	`\sin(x)`
`sinh`	`\sinh(x)`
`sqrt`	`\sqrt{x}`
`sum`	`\displaystyle\sum_{i=0}^n x_i`
`tan`	`\tan(x)`
`tanh`	`\tanh(x)`

Operators: +, -, *, /, ^, %

Braces: (), [], {}

Floating points: ., ,

Functions have only one argument, provided in braces. Operators must have two operands except minus (if it is the first character of equation or braced expression).

sum and prod sums and multiplies all elements in variable if it is numpy.ndarray and produces a float.

! There is no error handling yet !