Identifying the start of good data in a list

Mensanator mensanator at aol.com
Tue Aug 26 19:16:55 EDT 2008


On Aug 26, 4:49 pm, tkp... at hotmail.com wrote:
> I have a list that starts with zeros, has sporadic data, and then has
> good data. I define the point at  which the data turns good to be the
> first index with a non-zero entry that is followed by at least 4
> consecutive non-zero data items (i.e. a week's worth of non-zero
> data). For example, if my list is [0, 0, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8,
> 9], I would define the point at which data turns good to be 4 (1
> followed by 2, 3, 4, 5).
>
> I have a simple algorithm to identify this changepoint, but it looks
> crude: is there a cleaner, more elegant way to do this?
>
>     flag = True
>     i=-1
>     j=0
>     while flag and i < len(retHist)-1:
>         i += 1
>         if retHist[i] == 0:
>             j = 0
>         else:
>             j += 1
>             if j == 5:
>                 flag = False
>
>     del retHist[:i-4]
>
> Thanks in advance for your help
>
> Thomas Philips

Here's my attempt:

LL = [0, 0, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

i = 0

while (i<len(LL)) and (0 in LL[i:i+5]):
    i += 1

print i, LL[i:i+5]

##
##    4 [1, 2, 3, 4, 5]
##



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