CODEWITHSUNDEEP
python
from __future__
from __future__

Reputation: 315

Why I got an Index Error?

ant=['1']  
round = 30  

while round:  
    ant += '!'  
    next = []  
    start = 0  

    for current in range(len(ant)):  
        if ant[current] != ant[start]:  
            next.append(str(current-start)+ant[start])  
            start = current  
    ant = "".join(next)  

    round-=1  

print len(ant)

I got this source in a blog and tried to run this on 3.2.

(It's about making the ant sequence. [1,11,12,1121,&c]

But at line 10, 'IndexError : string index out of range' pops and I hardly understand why.

Upvotes: 0

Views: 132

Answers (2)

shihongzhi
shihongzhi

Reputation: 1931

your code is run fine on my computer. My python version is 2.7

the len(ant) is 5808

But I think you python code is not very clear and not pythonic. You can read this link and this

for example, use this

for index, x in enumerate(ant):

instead of for current in range(len(ant)):

And don't use ant +='!'. It should be ant.append('!')

Good Luck

Upvotes: 1

Amber
Amber

Reputation: 526573

Your code runs fine for me.

test.py:

ant=['1']
round = 30

while round:
    ant += '!'
    next = []
    start = 0

    for current in range(len(ant)):
        if ant[current] != ant[start]:
            next.append(str(current-start)+ant[start])
            start = current
    ant = "".join(next)

    round-=1

print len(ant)

$ python test.py
5808

Upvotes: 1

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