Alan Gauld via Tutor wrote:
> Forwarding to tutor list. Always use Reply All when responding to list
> mail.
>
>> Sorry, to be a little bit more descriptive. I'd like to loop from 1 to 35
>> but within this loop there are divisions which I need to prefix that
>> particular division number.
>
>> My output would look like this:
>>>>>>>>>>>>>>>>
> 1 1
> 1 2
> 1 3
> 1 4
> 1 5
> 1 6
> 1 7
> 1 8
> 1 9
> 1 10
> 1 11
> 1 12
> 2 13
> 2 14
> 2 15
> 2 16
> 2 17
> 2 18
> 2 19
> 2 20
> 3 25
> 3 26
> 3 27
> 3 28
> 3 29
> 3 30
> 3 31
> 3 32
> 3 33
> 3 34
> 3 35
>>>>>>>>>>>>>>>>
>
> You can't specify the blocks as just (12,20,.35) since you are using
> non-contiguous blocks - you have a gap between 20 and 25.
>
> So your definition needs to be (1,12),(13,20),(25,35) to specify
> the missing rows. But you can arguably simplify the code a little:
>
> blocks = ((1,13),(13,21),(25,36))
> for prefix, block in enumerate(blocks):
> for n in range(*block):
> print prefix+1, n
>
> its very similar to your code but using tuple expansion in range()
> cleans it up a little bit and the names hopefully make the intent
> clearer.
As Alan says, you need to specify the gaps. A simple if hackish way is to
use negative numbers:
def expand(ends):
start = 1
for end in ends:
if end < 0:
start = -end
else:
end += 1
yield (start, end)
start = end
blocks = [12, 20, -25, 35]
for index, span in enumerate(expand(blocks), 1):
for x in xrange(*span):
print index, x
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