List of lists chunked into sublists

Question

I have a list of lists I'm using as a data container. I've left all of my debugging code in, everything goes to console so I can follow it through, which explains some of the more redundant print statements.

It's created by iterating through and making one long list that looks like:

[['Arsenal', 2.47, 1.2, 0.89, 'Chelsea', 2.15, 0.8, 1.21,...

The sublists are all of uniform length (9 elements), so I used the following to chunk it, which is taken from here :

# This function should chunk the 'file', as when we run the above code, 
# we'll end up with one incredibly long list that contains every team on the same line
def chunker(seq, size):
    return (seq[pos:pos + size] for pos in xrange(0, len(seq), size))

for group in chunker(league_stats, 9):
   print repr(group)
   final_stats.append(repr(group))
   print "printing final stats"
   print final_stats
   print "and here's a line break" 

It then should look like this:

[['Arsenal', 2.47, 1.2, 0.89], ['Chelsea', 2.15, 0.8, 1.21]...]

But if I print it it's showing as:

["['Arsenal', 2.47, 1.2, 0.89]", ['Chelsea', 2.15, 0.8, 1.21|]..."]

If i iterate through it, it seems to show as expected

So that seems to have made each entire sublist a string, rather than a list, is that right? This has two weird knock ons - if I access elements using final_stats[0][2], for example, it gives me an 'A' instead of 'Arsenal', which I would expect.

The other, of course, is that I can't run logical operations against list elements - what's the best way to chunk the long list, or to stop this from happening?

If you need the full code (not included here for brevity), then it's here - I suspect that this question was inadvertantly caused by the issue in this post.

Someone on that answer suggested using dictionaries as a better data container - I'm pretty happy with the list structure, and it feels (to me as a newbie) a bit simpler for what I want to do - these data structures are always uniform sizes, so I don't want to change the data types unless I really have to. I think it's a helpful thing I'll look into long term.

Answer 1

repr() gets the representation of a string. ie:

print repr("""Hello!
this is a test string
yay.""")

Returns:

'Hello!\nthis is a test string\nyay.'

In your code, it is converting a list to a string, and that is why when you do [0][2] you get a character and not something you would expect.

There's no need to call it in your code. Just append the chuncked list normally.