从用户输入到python格式化数学表达式

Question

I want to be able convert the input of a mathematical expression from a user to the python format for math expressions. For example if the user input is:

3x^2+5

I want to be able to convert that into

3*x**2+5

so that I can user this expression in other functions. Is there any existing library that can accomplish this in Python?

Answer 1

You can use simple string formatting to accomplish this.

import re

expression = "3x^2+5"

expression = expression.replace("^", "**")
expression = re.sub(r"(\d+)([a-z])", r"\1*\2", expression)

For more advanced parsing and symbolic mathematics in general, check out SymPy 's parse_expr .