basic calculator II

 1def calculate(S):
 2    S, s, n, p = f"{S}+0", [], 0, "+"
 3    ops = {
 4        "-": lambda x: s.append(-x),
 5        "+": lambda x: s.append(x),
 6        "*": lambda x: s.append(s.pop() * x),
 7        "/": lambda x: s.append(int(s.pop() / x)),
 8    }
 9    for i in range(len(S)):
10        if S[i].isdigit():
11            n = n * 10 + int(S[i])
12        elif not S[i].isspace():
13            ops[p](n)
14            n, p = 0, S[i]
15    return sum(s)
16
17print(calculate("3+59*10/100"))