I've moved my App to GAE and I'm having real problems with this select
again. Is there a good way to do this on GAE? Do I just have to look
up each idnum in my list one at a time? I've tried that and it's just
terribly slow due to the number of lookups that have to be performed.
What's the prefered 'trick' to make this run on GAE?
On Sep 12, 7:01 pm, Chris S <sanders.ch...@gmail.com> wrote:
> Hu, some more troubleshooting has shown.
>
> rows=sqldb(sqldb.item.idnum.belongs(idnumList)).select
> (sqldb.item.idnum,sqldb.item.name)
> Doesn't perform as I think it was intended in the above code. Instead
> it returns a row which is simply (item.idnum,item.name). Literally
>
> Fixing it with
> rows=sqldb(sqldb.item.idnum.belongs(idnumList)).select()
> Works just fine as now it actually selects all the items of interest.
> Then with the command from above:
> maps=dict([str(row.idnum),row.name]for row in rows) *note i happen to
> be storing these ID's as strings
>
> We get a dictionary which I can access by ID-number and returns the
> item name. I'm thrilled, and I've learned a lot too about both Python
> and web2py today.
>
> On Sep 12, 6:29 pm,ChrisS <sanders.ch...@gmail.com> wrote:
>
> > Guess I should have looked a little before asking. You can use an if
> > statement inside of that comprehension line. So (for anyone who finds
> > this later) you can just make it.
>
> > new_items=[maps[item] for item in items if maps.has_key(item)]
>
> > Yea!
>
> > On Sep 12, 6:25 pm,ChrisS <sanders.ch...@gmail.com> wrote:
>
> > > Oh that's beautiful. One select and I'm set. I've got it up and
> > > running and it's pointed out a small problem for me.
>
> > > How can I handle and id (int items from your example) that isn't
> > > present in the table? Simply skipping it would be fine for now. I'll
> > > see what I can come up with but I'm new to Python (and coding in
> > > general) so the 'list comprehension' as I think it's called is still a
> > > bit of a new concept.
>
> > > On Sep 12, 4:20 pm, mdipierro <mdipie...@cs.depaul.edu> wrote:
>
> > > > You are making a lot of selects and this may be slow. I suggest
>
> > > > ## input
> > > > items=[... a list of ids...]
>
> > > > ##table
> > > > db.define_table('item',Field('name'))
>
> > > > ## algorithm
> > > > rows=db(db.item.id.belongs(items)).select(db.item.id,db.item.name)
> > > > maps=dict([(row.id,row.name) for row in rows])
> > > > new_items=[maps[item] for item in items]
>
> > > > and now you only have one query
>
> > > > On Sep 12, 4:02 pm,ChrisS <sanders.ch...@gmail.com> wrote:
>
> > > > > Update:
>
> > > > > ----------------
> > > > > for idnum in idnumList:
> > > > > for row in sqldb(sqldb.item.idnum==idnum).select():
> > > > > name=row.name
> > > > > Dictionary['Reagents']=list.replace(idnum,name)
> > > > > ------------------
>
> > > > > Is working ... sort of. Thus far I have it replacing one number in
> > > > > the list I'll look at it more later and post the whole solution when I
> > > > > figure it out. It should be noted. When working with the Shell to
> > > > > test script only one Quarry can be made, any further DB quarry's
> > > > > result in an error until you reload the shell!
>
> > > > > On Sep 12, 1:12 pm,ChrisS <sanders.ch...@gmail.com> wrote:
>
> > > > > > I'm trying to go through a list of dictionary's and replace one of
> > > > > > the
> > > > > > key's fields (an idnumber) with another field from a table. The
> > > > > > code
> > > > > > currently looks like:
>
> > > > > > --------------
> > > > > > regex = re.compile(r'\[(\d+)\,') #Match's my item numbers
> > > > > > for Dictionary in DictList:
> > > > > > list = Dictionary['Reagents']
> > > > > > idnumList = regex.findall(list)
> > > > > > ----------------
>
> > > > > > This gives me a nice list (idnumList) with id numbers in it.
> > > > > > However
> > > > > > I can't seem to find a way to take each of these idnumbers, look
> > > > > > them
> > > > > > up in a table and return a different field (name).
>
> > > > > > I've been trying:
>
> > > > > > ----------------
> > > > > > for idnum in idnumList:
> > > > > > item=sqldb(sqldb.item.idnum==idnum.isdigit()).select()
> > > > > > Dictionary['Reagents']=list.replace(idnum,item.name)
> > > > > > ---------------
>
> > > > > > But I'm told item.name isn't a valid field. Am I going about this
> > > > > > the
> > > > > > right way, can someone point me in the right direction?
>
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"web2py-users" group.
To post to this group, send email to web2py@googlegroups.com
To unsubscribe from this group, send email to
web2py+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/web2py?hl=en
-~----------~----~----~----~------~----~------~--~---
