Steven Bethard wrote:
> The question is not how easy it is to write, > but how many times it's going to get written.
but with that logic we could create a standard "looping" construct called loop(x) that would stand in for
for i in range(x):
IMHO, that example is quite the opposite of what you are advocating. range() is a simple function, and one which could be written by anyone with little chance of flaw. Why not do:
i = 0
while i < x
...
i += 1? The three arguments to range are all present (how valuable are a few defaults). It's more general. You can extend it and modify it easily. These are all the same properties of bunch. Easy things have value; maybe that applies here, but saying that it is easy is not the same as saying it isn't valuable. For instance, we now have the sorted function, equivalent to:
def sorted(lst, *args, **kw):
lst = list(list)
lst.sort(*args, **kw)
return lstPeople have been writing this function over and over. Only there are a few subtlely different ways you can implement it, and you'll never know which from the function name alone. dict's keyword argument constructor is similar. And maybe bunch is similar; at least, I'd argue for or against it based on that, not merely on how easy it is to reimplement. "If the implementation is easy to explain, it may be a good idea." (import this)
If it existed, I'd probably use it some where I'm currently using dictionaries (but where I don't want to give the data behavior), and I'd probably subclass it. Now, when it doesn't exist, I frequently implement the behavior in classes that have other logic as well, and I almost never use it without logic; I use dict() with its keyword argument constructor, and just suffer the quotation marks when I'm retrieving members.
BTW, in class that look like bunch, I usually implement it like:
class bunch(object):
def __init__(self, **kw):
for name, value in kw.items():
# IMPORTANT! This is subclass friendly: updating __dict__
# is not!
setattr(self, name, value) def __call__(self, **kw):
# I'm not entirely happy with this:
new_values = self.__dict__.copy()
new_values.update(kw)
return self.__class__(**new_values)-- Ian Bicking / [EMAIL PROTECTED] / http://blog.ianbicking.org -- http://mail.python.org/mailman/listinfo/python-list
