passing an array type to a plpython procedure

From: Rajarshi Guha <rguha(at)indiana(dot)edu>
To: pgsql-general(at)postgresql(dot)org
Subject: passing an array type to a plpython procedure
Date: 2007-03-11 22:37:26
Message-ID: 1173652646.4908.10.camel@panda
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Hi, I have a table in which a column is of type real[12]

I also have a function written in pl/Python that will accept two
arguments of type real[12].

However when I send in the values by doing:

select sim(ARRAY[1,1,1,1,1,1,1,1,1,1,1,1], ARRAY[1,1,1,1,1,1,1,1,1,1,1,1])

I get an error indicating that the input args are of type 'str' rather
than a list type as I would have expected. I found this posting
(http://www.thescripts.com/forum/thread399934.html) from 2005, which
indicates that a pl/Python procedure will not see an array type as array
but rather as a string.

Has this aspect been updated? My current code parses the string, to get
at the array elements (which is obviously prone to failure etc etc) and
I'm sure I could get a bit of a speed up if I could avoid this. My code
looks like:

create or replace function momsim3d(real[12], real[12]) returns real as
'
query = args[0]
target = args[1]

query = query[1:len(query)-1]
target = target[1:len(target)-1]

query = [float(x) for x in query.split(",")]
target = [float(x) for x in target.split(",")]

sum = 0.0
for i in range(0,12): sum += abs(query[i] - target[i])
return 1.0/(1.0+sum/12.0)
' language plpythonu;

Ubuntu 6.10
Postgresql 7.4

Thanks,

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Rajarshi Guha <rguha(at)indiana(dot)edu>
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