Function substitute_variable 

pub fn substitute_variable(
    expr: &Expression,
    var: &Symbol,
    value: &Expression,
) -> Expression

Substitute a value for a variable in an expression

Arguments

• expr - The expression
• var - The variable to substitute
• value - The value to substitute

Examples

use mathhook_core::{Expression, symbol};
use mathhook_core::calculus::integrals::rational::helpers::substitute_variable;
use mathhook_core::simplify::Simplify;

let x = symbol!(x);
let expr = Expression::add(vec![
    Expression::pow(Expression::symbol(x.clone()), Expression::integer(2)),
    Expression::integer(1),
]);

let result = substitute_variable(&expr, &x, &Expression::integer(3));
assert_eq!(result.simplify(), Expression::integer(10));