MathJSON Solver is a Python module to numerically evaluate MathJSON expressions. It was created by Longenesis to add numerical evaluation capability of user generated mathematical expressions in Longenesis digital health products and later released as open source project. Its development was inspired by CortexJS Compute Engine.
Please ask questions and share feedback in our Gitter chat https://gitter.im/mathjson-solver/community.
Added Str construct. It tries to convert value to string.
We changed the behavior of Average to be more forgiving. In version 1.4.0 Average accepts arrays like [2, 4 ,"6"] and internally converts numeric strings to floats.
Also, it skips values that cannot be converted to numeric. Internally Average will convert array [2, "three", 4 ,"6"] to [2.0, 4.0 ,6.0]. When given an empty array, Average now returns None instead of throwing an error.
from mathjson_solver import create_solver
parameters = {"x": 2, "y": 3}
expression = ["Add", "x", "y", 4]
solver = create_solver(parameters)
answer = solver(expression)
print(answer)
# 9, because 2+3+4=9Make sure you have pytest installed. Then cd into project directory and run:
pytestWe welcome your contributions in the form of pull requests.
- Fork the repo;
- Make improvements;
- Make a pull request to share your improvements with the community and to include it into official release.
Sum(aliasAdd)SubtractMultiplyDivideNegatePowerRootSqrtSquareExpLogLog2Log10
ArrayMaxMinAverageMedianLenAllAny
IfSwitchEqualGreaterGreaterEqualLessLessEqualNotEqual
InNotInContainsAnyOfContainsAllOfContainsNoneOf
StrIntFloatNot
Constants
["Add", 2, 4, 3] # 2+4+3=9
["Subtract", 10, 5, 2] # 10-5-2=3
["Add", 5, 4, ["Negate", 3]] # 5+4+(-3)=6
["Multiply", 2, 3, 4] # 2*3*4=24
["Divide", 10, 5] # 10/5=2.0
["Divide", 10, 4] # 10/4=2.5
["Power", 2, 3] # 2^3=8
["Root", 9, 2] # √9=3.0
["Root", 8, 3] # ∛8=2.0
["Sqrt", 9] # √9=3.0
["Square", 4] # 4^2=16
["Exp", 2] # e^2≅7.389
["Divide", 10, ["Add", 2+3]] # 10/(2+3)=10/5=2
["Log", 2.7183] # ln(2.7183)≅1.0000
["Log2", 8] # log2(8)=3.0
["Log10", 1000] # log10(1000)=3.0
["Equal", 10, 10] # 10==10 = True
["Equal", 10, 12] # 10==10 = False
["Abs", -3.5] # |-3.5| = 3.5
["Round", -5.123456, 2] # -5.12
["Round", -5.123456, 0] # -5.0
["Round", -5.123456] # -5
["Array", 1, 2] # ["Array", 1, 2]
["Max", ["Array", 1, 2, 3, 5, 2]] # 5
["Max", ["Array", 1, 2, ["Sum", 2, 4, 3], 5, 2]] # 9
["Median", ["Array", 1, 2, 3, 5, 2]] # 2
["Average", ["Array", 1, 2, 3, 5, 2]] # 2.6
["Average", ["Array"]] # None
["Length", ["Array", 1, 2, 3, 5, 2, 9]] # 6
["Length", ["Array"]] # 0
["Any", ["Array", 0, 0, False, 0, 0]] # False
["Any", ["Array", 0, 1, False, 0, 0]] # True
["All", ["Array", 0, 1, False, 0, 0]] # False
["All", ["Array", 0, 1, False, "", 0]] # False
["All", ["Array", 2, 1, True, "zz", 2]] # True
["Int", "12"] # 12
["Int", "12.2"] # 12
["Float", "12.2"] # 12.2
["Str", 12] # "12"
["Str", "12"] # "12"
["Str", "aabb"] # "aabb"
["Not", True] # False
["Not", 0] # True
["In", 2, ["Array", 1, 2, 3]] # True
["In", 4, ["Array", 1, 2, 3]] # False
["ContainsAnyOf", ["Array", 1, 2, 3], ["Array", 3, 4, 5, 6]] # True
["ContainsAnyOf", ["Array", 1, 2, 3], ["Array", 4, 5, 6]] # False
["ContainsAllOf", ["Array", 1, 2, 3], ["Array", 1, 2, 3]] # True
["ContainsAllOf", ["Array", 1, 2], ["Array", 1, 2, 3]] # False[
"Constants",
["constant_name1", <expression>],
["constant_name2", <expression>],
["constant_name3", <expression>],
...,
<expression>
]
Constants construct consists of keyword "Constants" followed by arbitrary number of name&value pairs. The last element in Constants construct is the expression to calculate using the defined constants.
The following example has two constants defined - x=10 and y=20. Then the sum of these two constants is calculated and returned.
[
"Constants",
["x", 10],
["y", 20],
["Add","x", "y"]
][
"If",
[
<true-or-false-expression>,
<expression-to-calculate>
],
[
<elseif-true-or-false-expression>,
<expression-to-calculate>
],
...,
<else-expression-to-calculate>
]
Example
[
"If",
[
["Equal", 1, 0],
10
],
[
["Equal", 2, 2],
20
],
9000
]This construct translates to:
if 1 == 0 then 10
elif 2 == 2 then 20
else 9000
If expression do not need to be strictly boolean. Any value that is not false are considered true.
["Switch", <on-expression>, <default-result-expression>, [<case1-expression>, <result-expression>], ...],
Switch construct consists of keyword "Switch" followed by expression whose value will be compared to Cases' values. Then comes the default value. Then follows arbitrary number of Cases.
Example
["Switch", "color", 100, ["red", 10], ["blue", 20], ["green", 30]],The expression in this example will make solver to look for a constant (or a parameter) with the name "color". If "color" is "red", expression evaluates to 10, if "blue" - to 20, if "green" - to 30. Otherwise to 100. Please note that "color" here is a valid expression that evaluates to the actual value of "color" whether it is a parameter or constant.
A MathJSONException is raised when expression cannot be evaluated. Import MathJSONException to handle it:
from mathjson_solver import create_solver, MathJSONException
solver = create_solver({})
try:
solver(["Divide", 1, 0])
except MathJSONException:
pass
# invoke your own exception logger hereLeft unhandled, the exception will look like MathJSONException("Problem in Divide. ['Divide', 1, 0]. division by zero").