list comprehension (searching for onliners)

[Gerardo Herzig]

Hi all: I have this list thing as a result of a db.query: (short version)
result = [{'service_id' : 1, 'value': 10},
{'service_id': 2, 'value': 5},
{'service_id': 1, 'value': 15},
{'service_id': 2, 'value': 15},
]

and so on...what i need to do is some list comprehension that returns me
something like

result = [
{
'service_id' : 1, 'values': [ {'value': 10},
{'value': 15}]
},
{
'service_id' : 2, 'values': [ {'value': 5}, {'value': 15}]
}


My problem now is i cant avoid have "repeteated" entries, lets say, in
this particular case, 2 entries for "service_id = 1", and other 2 for
"service_id =2".
Ill keeping blew off my hair and drinking more cofee while searching for
this damn onliner im looking for.

Thanks dudes.
Gerardo

 

[Jon Clements]

Hi all: I have this list thing as a result of a db.query: (short version)
result = [{'service_id' : 1, 'value': 10},
{'service_id': 2, 'value': 5},
{'service_id': 1, 'value': 15},
{'service_id': 2, 'value': 15},
]

and so on...what i need to do is some list comprehension that returns me
something like

result = [
{
'service_id' : 1, 'values': [ {'value': 10},
{'value': 15}]
},
{
'service_id' : 2, 'values': [ {'value': 5}, {'value': 15}]
}


My problem now is i cant avoid have "repeteated" entries, lets say, in
this particular case, 2 entries for "service_id = 1", and other 2 for
"service_id =2".
Ill keeping blew off my hair and drinking more cofee while searching for
this damn onliner im looking for.

If you import itertools and have your DB query return in order of
service_id (or sort the list after retrieving result), then...


[ [dict(service_id=key),[dict(value=n['value']) for n in value]] for
key,value in itertools.groupby(result,lambda x: x['service_id']) ]

.... is more or less what you want.

Jon.

 

[Roberto Bonvallet]

Gerardo Herzig wrote:
[...]

and so on...what i need to do is some list comprehension that returns me
something like

[...]

You don't _need_ a list comprehension, you just _want_ one

[...]

Ill keeping blew off my hair and drinking more cofee while searching for
this damn onliner im looking for.

I know, trying to put complex logic in one line makes you do all that.

Go for the multiliner!