> I understand f.next(), but [gloss.setdefault(l,f.next()) for l in f]
> is beyond me at this point.
[expr for l in f] is a "list comprehension". expr is an _expression_ that
may involve l.
result = [expr for l in f] # is equivalent to:
result = []
for l in f:
result.append(expr)
"list comprehension" (once understood) is often easier to read and more
efficient than the for loop.
result = xxx.setdefault(key, newvalue) is a dictionary method that tries
to get an item from the dictionary xxx using key. If the key is not in
the dictionary it adds the item assigning it newvalue. Equivalent to:
if key not in xxx:
xxx[key] = newvalue
result = xxx[key]
Note that list comprehension and setdefault both return something. In my
code the returned values are ignored. The outcome (populating a
dictionary via a loop) is a "side effect".
Thank you Bob. This is much to think about. I very much appreciate your concise explanation.
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