[Pytables-users] In-kernal for subset?

[Adam D. <ade...@ex...>]

I am trying to find all cases where a value transitions above a threshold.  So, my code first does a getwherelist to find values that are above the threshold, then it uses that list to find immediately prior values that are below.  The code is working, but the second part, searching through just a smaller subset is much slower (First search is on the order of 1 second, while the second is a minute).
Is there any way to get this second part of the search in-kernal?  Or any more general way to do a search for values above a threshold, where the prior value is below?
Essentially, what I am looking for is a way to speed up that second search for "all rows in a prior defined list, where a condition is applied to the table"

My table is just seconds and values, in chronological order.

Here is the code that I am using now:

h5data = tb.openFile("AllData.h5","r")
table1 = h5data.root.table1

#Find all values above threshold:
thelist= table1.getWhereList("""Value > 150""")

#From the above list find all values where the immediately prior value is below:
transition=[]
for i in thelist:
if (table1[i-1]['Value'] < 150) and (i != 0) :
transition.append(i)

Thanks,