In my experience working with this I fired out that it is better to use "haversine" directly on database, you can find haversine functions for MySQL, Postgres and even for SQlite.
I dont know how one can write haversine with DAL api, but you can do it with executesql() as you are going to turn this in to json. BTW: you can use rows.exclude(lambda row: row.x == y) to remove items I guess you can combine rows with Rows += Rows/ or Rows &= Rows if they are scheme identically. Take a look at row.exclude() on dal chapter of the book On Mon, Sep 17, 2012 at 4:51 PM, Kenny <nis...@gmail.com> wrote: > Basically, I get the place data with longitude and latitude, calculate it > if it's more than 3000 miles, remove that row from Rows. > I am sure that this is wrong. If I can remove the row from fetch rows, how > can I add extra columns to the rows for distance between two points? > P.S the result has to be Jsoned. > > Here's the code > > def tester(): > items = db(db.dine_promotion.place_id==db.place.id).select() > > latitude =float(23.790457) > longitude =float(-47.602542) > for row in items: > if row.place.latitude: > a=float(row.place.latitude) > b=float(row.place.longitude) > dist="%.2f" % calc_distance(latitude,longitude,a,b) > if dist > 3000: > items.remove(row) > return dict(restaurants = items) > > -- > > > > --
