Python break from if statement to else

Question

(I'm a Python newbie, so apologies for this basic question, I for some reason couldn't find an answer to.)

I have a nested if statement with the if statement of an if/else block. In the nested if statement, if it it meets the criteria, I'd like the code to break to the else statement. When I put a break in the nested if, though, I'm not sure if it's breaking to the else statement.

I'd like to find the longest substring in alphabetical order of a given string, s. Here's my code:

s = 'lugabcdeczsswabcdefghij'
longest = 1
alpha_count = 1
longest_temp = 1
longest_end = 1
for i in range(len(s)-1):
    if (s[i] <= s[i+1]):
        alpha_count += 1
        if (i+1 == (len(s)-1)):
            break
    else:
        longest_check = alpha_count
        if longest_check > longest:
            longest = longest_check
            longest_end = i+1
        alpha_count = 1
print(longest)
print('Longest substring in alphabetical order is: ' + 
    s[(longest_end-longest):longest_end])

(Yes, I realize there's surely lots of unnecessary code here. Still learning!)

At this nested if:

if (i+1 == (len(s)-1)):
            break

...if True, I'd like the code to break to the else statement. It doesn't seem to break to that section, though. Any help?

Solution

break is used when you want to break out of loops not if statments. You can have another if statement that executes this logic for you like this:

if (s[i] <= s[i+1]):
    alpha_count += 1
elif (i+1 == (len(s)-1)) or (add boolean expression for else part in here too something like s[i] > s[i+1]):
    longest_check = alpha_count
    if longest_check > longest:
        longest = longest_check
        longest_end = i+1
    alpha_count = 1

What this snippet is doing is evaluating two booleans, both are for the else part. However, it says either execute in case of else from first if or in case of (i+1 == (len(s)-1))

Comments

[Jim]

I believe the first if statement should have an and boolean as well: if (s[i] <= s[i+1]) and (i+1 < (len(s)-1)): alpha_count += 1 elif (s[i] <= s[i+1]) and (i+1 == (len(s)-1)):

[Kafo]

if you want the first one to execute whenever i + 1 < (len(s) - 1)