On 21/01/2011 02:35, Jean-Francois wrote:
Hi,

In the following example, I don't understand why attribute 'data' is
not reset when I get the new instance of Bag
It works if I make a copy (data[:]) but I want to understand why

Thanks


class Bag(object):
        def __init__(self, data = []):
                self.data = data
                #self.data = data[:]
        def add(self, x):
                self.data.append(x)

bag = Bag()
print bag.data
bag.add('toto')
print bag.data
bag = Bag()      # new instance of Bag, all attributes clear?
print bag.data   # 'toto' is still there !!!

See:
    http://effbot.org/zone/default-values.htm
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