Help me find a way to calculate a string that contain numbers and + and -

Question

Example :
input : "2 +4 +7-9+1-3"
Output: 2

Answer 1

import re
mystring = "2+4 +7-9+1-3"
patten = r"[+-]?\d+"
print(sum(int(x) for x in re.findall(patten, mystring)))

Answer 2

MohammadReza Yadollahi
for single-digit numbers only:

https://code.sololearn.com/cm9V4xL3M7A4/?ref=app

Answer 3

I want to write function like eval or sympy.sympify and dont want to use them

Answer 4

print(eval("2 +4 +7-9+1-3"))