From: "karsten" <karsten@terragis.net>
To: <pgsql-sql@lists.postgresql.org>
Subject: plphyton function - return each list value as a row ?
Date: Sat, 25 Jul 2020 14:26:45 -0700
Message-ID: <8B3D52FE28844B478ADD80DE30CF9F36@terragispc>
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Hi All,
 
I am trying to create my first plphyton function ( retrieving earthquake
data from an API) .
Overall I was able to get one single row to be returned, but am struggling
how to return the entire list I have as multiple rows - see below. Currently
I get the following error when running the GetEartquakeAll function:

select GetEartquakeAll('2020-01-01' ,'2020-03-01', -120, 40,200, 1.7)
gives me
ERROR: length of returned sequence did not match number of columns in row

How can I 'simply' return each list value as a row ? 
Thanks
Karsten Vennemann
 
CREATE OR REPLACE FUNCTION GetEartquakeAll(start date ,stop date, lon float,
lat float,radius int, minmagnitude float) RETURNS equake_values AS $$
  import urllib2
  import json as json
  data =
urllib2.urlopen('https://earthquake.usgs.gov/fdsnws/event/1/query?format=geo
json&starttime=%s&endtime=%s&latitude=%s&longitude=%s&maxradiuskm=%s&minmagn
itude=%s&orderby=magnitude' % (start,stop,lat,lon,radius,minmagnitude))
  js_data = json.load(data)
  equake = js_data
  equakearray = []
  a = 0
  for i in equake['features']:
    equakeplace = i['properties']['place'] # tile for earthquake location
    magnitude =   i['properties']['mag']
    qlong =       i['geometry']['coordinates'][0]
    qlat =        i['geometry']['coordinates'][1]      
    equakevalue = {"place": equakeplace, "magnitude": magnitude , "qlong":
qlong, "qlat": qlat}
    equakearray.append(equakevalue)
    a = a+1
  return equakearray
$$ LANGUAGE plpythonu; 
           
# create custom data type that is returned from equake  data API query
CREATE TYPE equake_values AS ( 
  place text,
  magnitude float,
  qlong  float,
  qlat  float
);