Simple Python code doesn't work with Brython

Question

I've started learning Python (again). This simple code with a cycle works by itself. But when I put it into a Brython it doesn't. No part of it works until I comment out everything, but simple alert() commands. I've tried just a "i+=1" cycle — doesn't work. I've checked indents and spacing, too.

What is wrong?

Thank you.

 from browser import document
            from browser import alert
            i=0
            r = ''
            s = 'nín'
            d = {'nín':'нин','hǎo':'хао','lǎo':'лао','wài':'уай','ī': 'ӣ', 'bī': 'бӣ', 'jī': 'чжӣ', 'nī': 'нӣ', 'nīn': 'нӣнь', 'nīng': 'нӣн'}
            def set_r():
                r = '12345'
                alert(i)
                #while i < len(s):
                    #flag = True
                    #for j in range(4):
                        #t = s[i:i+j]
                        #if t in d:
                        #r += d[t]
                        #i += j
                        #flag = False
                    #break
                #if flag:
                    #r += s[i]
                #i += 1
            alert( s );
            set_r();

I wanted any part of the Python code to work in the browser, like a simple cycle with an integer.

Welcome ! Please format your code with proper indentation. – Talha Tayyab Mar 07 '23 at 09:56 — Talha Tayyab, Mar 07 '23 at 09:56
To be easier to read? Because it works as is, too. – Wolong Gao Mar 07 '23 at 10:18 — Wolong Gao, Mar 07 '23 at 10:18

score 0 · Accepted Answer · answered Mar 07 '23 at 10:24

I see your indentation is wrong, remember Python is sensitive to this and the code will fail if not correct. Remember to always indent the block of a while or if statement (and similar).

When defining the variables outside the methods (globally) in a static context, use the global keyword followed by the variable names inside of the methods to refer to them. Otherwise the set_r method will not see the globally defined variables.

Also, you don`t need semicolon after a line in python like in other languages.

Try the following code:

from browser import document
from browser import alert

i=0
r = ''
s = 'nín'
d = {'nín':'нин','hǎo':'хао','lǎo':'лао','wài':'уай','ī': 'ӣ', 
     'bī': 'бӣ', 'jī': 'чжӣ', 'nī': 'нӣ', 'nīn': 'нӣнь', 'nīng': 'нӣн'}

def set_r():
    global r, i  # Add these lines to access and modify the global variables
    r = '12345'
    alert(i)
    while i < len(s):
        flag = True
        for j in range(4):
            t = s[i:i+j]
            if t in d:
                r += d[t]
                i += j
                flag = False
        if flag:
            r += s[i]
        i += 1

alert(s)
set_r()

Hope this helps!

OK, will try and reply. I figured this messy indentation was kind of alright, since it worked outside of Brython context. Thanks. — Wolong Gao, Mar 07 '23 at 15:21
Well, that was fast. I understand the solution, I don't understand the problem :) Because it kind of worked before anyway... Thanks. — Wolong Gao, Mar 07 '23 at 15:28

Simple Python code doesn't work with Brython

1 Answers1