Math from left to right (avoid standard operator precedence)

Grasshopper
,
1

I have text strings such as mathematical expressions (e.g. 11 + 50 * 10), and I need to calculate the resulting number doing the math from left to right discarding the fact that multiplication precedes addition. For 11 + 50 * 10:
If i connect this string to a num component I will get a result of 11+500 = 511.
What I need is that 11+50 is calculated first (=61), followed by the multiplication 61 * 10 = 610
Is this possible? The strings can be of various lengths with more operators than in this example (e.g. 11 + 50 * 10 * 26 + 38 + 9 * 56 * 26, which should give → 23 160 592).

2

You can calculate expressions from left to right in Python with this simple script:

tokens = []
temp = ''
for char in exp:
    if char.isdigit():
        temp += char
    elif char in '+-*/':
        if temp:
            tokens.append(temp)
            temp = ''
        tokens.append(char)
if temp:
    tokens.append(temp)
exp = tokens[0]
for i in range(1, len(tokens), 2):
    exp = f"({exp}{tokens[i]}{tokens[i+1]})"
r = eval(exp)

Lason
Lason1396×328 19.4 KB

Lason.gh (5.2 KB)

1 Like
3

Cool, thank you Mahdiyar!