Question

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.

Answer 1

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