when you want only one and the first better use .select(limitby=(0,1)) and proper orderby, else you can be disappointed by performance...
2015-02-06 20:52 GMT+01:00 Anthony <[email protected]>: > rows = db(query).select() > > In the above, "rows" is a Rows object, which acts like a list of Row > objects. To extract a single Row object, you would do: > > row = rows[index] > > Specifically, to get the first Row, you would do: > > first_row = rows[0] > > rows.first() is simply equivalent to rows[0], except that if Rows happens > to be empty, instead of raising an exception, it will simply return None. > So, instead of doing: > > first_row = rows[0] if rows else None > > you can just do: > > first_row = rows.first() > > Anthony > > > > On Friday, February 6, 2015 at 2:18:13 PM UTC-5, Alex Glaros wrote: >> >> can someone please consolidate my knowledge or tell me where in >> documentation this is explained >> >> the "first()" in this line below: >> >> this_message = db(db.InternalMessage.id == request.get_vars.filter). >> select()*.first()* >> >> allows below to work in view: >> >> {{=this_message.created_by.last_name}} >> >> if the ".first()" is removed leaving this: >> >> this_message = db(db.InternalMessage.id == request.get_vars.filter). >> *select()* >> >> then view no longer works. First result is a single row, second result >> can be many rows. >> >> What is this concept called? >> >> Is first result a dictionary and second result a row? >> >> I understand that there is unacceptable ambiguity in the 2nd result with >> many possible rows but would like to know what the terms are called and >> where documented so I can read about it. >> >> Is .first() the only/best way to get a value into a single var (when no >> looping is necessary)? >> >> thanks >> >> Alex Glaros >> > -- > Resources: > - http://web2py.com > - http://web2py.com/book (Documentation) > - http://github.com/web2py/web2py (Source code) > - https://code.google.com/p/web2py/issues/list (Report Issues) > --- > You received this message because you are subscribed to the Google Groups > "web2py-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
