In search of python idiom for accessing arbitrary fields at run time

[mshiltonj]

I'm trying to find the preferred python idiom for access arbitrary
fields of objects at run time.


For example, say I have an object the business code will do
*something* with three arbitrary fields at a given time, but I don't
know what the three fields are at run time. In perl, I'd do something
like this:

sub three_fields{
my $self = shift;
my @fields = @_;

foreach my $field (@fields)
{
my $value = $self->$field; # this is the one I'm
interested in
[...]
}
}

In python, I'm doing something like this:

def three_fields(self, field1, field2, field3):
for field in (field1, field2, field3):
value = eval('self.' + field) # this is the one I'm
interested in
[...]

This seems to do what I expect it to do. I'm wondering if that's the
preferred or standard way to do this in python. I wasn't sure how to
tease the answer to this question out of Google.

Thanks.

 

[OKB (not okblacke)]

In python, I'm doing something like this:

def three_fields(self, field1, field2, field3):
for field in (field1, field2, field3):
value = eval('self.' + field) # this is the one I'm
interested in
[...]

This seems to do what I expect it to do. I'm wondering if that's the
preferred or standard way to do this in python. I wasn't sure how to
tease the answer to this question out of Google.

I believe you are looking for the getattr function.

--
--OKB (not okblacke)
Brendan Barnwell
"Do not follow where the path may lead. Go, instead, where there is
no path, and leave a trail."
--author unknown

 

[mshiltonj]

In python, I'm doing something like this:

def three_fields(self, field1, field2, field3):
for field in (field1, field2, field3):
value = eval('self.' + field) # this is the one I'm
interested in
[...]

This seems to do what I expect it to do. I'm wondering if that's the
preferred or standard way to do this in python. I wasn't sure how to
tease the answer to this question out of Google.

I believe you are looking for the getattr function.

--
--OKB (not okblacke)
Brendan Barnwell
"Do not follow where the path may lead. Go, instead, where there is
no path, and leave a trail."
--author unknown

Doh. I figured it'd by FAQish. :-/ Thanks.