To clearify the problem:
The data is the count of something, for example a[90]=10. a may be a dictionary if the range is huge and a list when the range is reasonably small. In the dictionary case, I can use a.setdefault(80, 0) if key 80 does not exist. In the list case, I have to check the length of list before I access it (or use exception).
This becomes troublesome when I need to do the following a lot.
b = a[80][1] + a[80][2] + a[80][3]
If I use the getItem function in my previous email, it will look like
b = getItem(getItem(a, 80, []), 1, 0) + getItem(getItem(a, 80, []), 2, 0) + getItem(getItem(a, 80, []), 3, 0)
What would be the best solution to handle this? Something like
b = df( a[80][1], 0) + df( a[80][2], 0) + df( a[80][3], 0)
would be reasonable but df can not be easily defined since the exception will be raised before function df is called. Something like
b = df( a, [80, 1], 0) + df( a, [80,2], 0) + df( a, [80, 3], 0)
would work if df is defined as
def df(a, idx, default):
try:
for i in range(0, idx):
a = a[ idx[i] ]
return a
except:
return 0but I am afraid that a for loop would bring serious performance problem.
Thanks.
Bo -- http://mail.python.org/mailman/listinfo/python-list
