Method to extract a column from Rows

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Anthony

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May 26, 2014, 1:36:34 PM5/26/14
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How about we add a method like this to the dal.Rows class:

def column(self, column=None):
    return [r[str(column) if column else self.colnames[0]] for r in self]

That way, you can do:

db(db.person).select().column('name')

and get a list of names. You can also do:

db().select(db.person.name).column()

and get the list of names without having to specify the "name" column as an argument. Is this useful?

Anthony

Massimo DiPierro

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May 26, 2014, 1:41:55 PM5/26/14
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I like it.

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Paolo Valleri

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May 26, 2014, 2:27:26 PM5/26/14
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I like it too.
Moreover regarding rows and row I have an annoying problem I would discuss to find out the right approach, my usual represents contain an in line if.
For example, given a table "student" with a field "name", the represent for the field name will be:

db.student.name.represent = lambda id, row: SPAN( row.name if 'name' in row else row.student.name), _class="a_special_class")

This code is the result of using the table student in a join or not. 
I've seen on the book that there is the possibility to set rows.compact =False, in this case my example will be something like:

db.student.name.represent = lambda id, row: SPAN( row.student.name ), _class="a_special_class")

However, it is not always feasible to set explicitly rows.compact = False. 
Currently I've in mind a new method, something like row.field('name') which will handle internally the issue I have reported. Or even better called column as the one proposed by Anthony for rows but in this case applied to row.
Thoughts?

Paolo

Anthony

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May 27, 2014, 6:46:13 PM5/27/14
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I can't easily generate a patch right now -- can you add that yourself, Massimo?

Anthony


On Monday, May 26, 2014 1:41:55 PM UTC-4, Massimo Di Pierro wrote:
I like it.

On May 26, 2014, at 12:36 PM, Anthony wrote:

How about we add a method like this to the dal.Rows class:

def column(self, column=None):
    return [r[str(column) if column else self.colnames[0]] for r in self]

That way, you can do:

db(db.person).select().column('name')

and get a list of names. You can also do:

db().select(db.person.name).column()

and get the list of names without having to specify the "name" column as an argument. Is this useful?

Anthony


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Massimo DiPierro

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May 27, 2014, 10:02:45 PM5/27/14
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Done yesterday. :-)

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Anthony

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May 28, 2014, 7:26:19 AM5/28/14
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I believe row['student.name'] will work whether or not compact=True (in that case, when it fails to find the key "student.name", it looks for just "name"). Is that a sufficient workaround?

Anthony
I like it.


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Paolo Valleri

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May 28, 2014, 7:43:32 AM5/28/14
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it words, thanks Anthony


 Paolo



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