[Pytables-users] creating numarray.array from python comprehension list

[<phi...@ho...>]

Hi list,

I want to select data from an hdf5 file using pytables.

for retrieving all the data from an Array (or a Table) object, i read 
the data and save it into a numarray.array using the read() function:
my_numarray_array = my_object.read().

for example:
readout = h.root.detector.readout
b=readout.read()
print b

That's really nice to use and i can easilly treat data after that.

My question is about selecting only a part of data:
Can i create directly a numarray.array object using a python list 
comprehension on an Array or a Table?

For the moment using list comprehension, i only get a list.

for example:
 >>> pressure = h.root.columns.pressure
 >>> a=[p for p in pressure]
 >>> print a
[25.0, 36.0, 49.0]
 >>> a=[p for p in pressure if p <36]
 >>> print a
[25.0]
 >>> type(a)
<type 'list'>

I want to get a numarray.array.

1. Can i cast the list into a numarray.array?
2. Can i copy all the data from the list to a numarray.array once?
3. Must i instrospect the list using the for elt in list: and add each 
data in a numarray?

Thanks a lot for your help,
Philippe