Question

I find myself writing this class often in my python code when I need a quick single use class.

class Struct(object):
   def __init__( self, **kwargs ):
      for k in kwargs:
         setattr(self,k,kwargs[k])

The basic idea is so I can do quick things like this:

foo = Struct( bar='one', baz=1 )
print foo.bar
foo.baz += 1
foo.novo = 42 # I don't do this as often.

Of course this doesn’t scale well and adding methods is just insane, but even so I have enough data-only throw-away classes that I keep using it.

This is what I thought namedtuple was going to be. But the namedtuple’s syntax is large and unwieldy.

Is there something in the standard library I haven’t found yet that does this as well or better?

Is this bad bad style? or does it have some hidden flaw?

update

Two concrete example to show why I don’t just use a dict. Both of these examples could be done with a dict but it obviously non-idiomatic.

#I know an order preserving dict would be better but they don't exist in 2.6.
closure = Struct(count=0)
def mk_Foo( name, path ):
   closure.count += 1
   return (name, Foo( name, path, closure.count ))

d = dict([
   mk_Foo( 'a', 'abc' ),
   mk_Foo( 'b', 'def' ),
   # 20 or so more
   ] )


@contextmanager
def deleter( path ):
   control = Struct(delete=True,path=path)
   try:      
      yield control
   finally:
      if control.delete:
         shutil.rmtree(path)

with deleter( tempfile.mkdtemp() ) as tmp:
   # do stuff with tmp.path
  
   # most contexts don't modify the delete member
   # but occasionally it's needed
   if keep_tmp_dir:
      tmp.delete = False
  

Answer 1

There is a python recipe for this (It just updates the instance’s dict instead of calling setattr)
Recipe 52308

class Bunch(object):
    def __init__(self, **kwds):
        self.__dict__.update(kwds)