Karim Liateni, 04.03.2010 01:23:
Steven D'Aprano wrote:
def skip_blanks(lines):
"""Remove leading and trailing whitespace, ignore blank lines."""
for line in lines:
line = line.strip()
if line:
yield line
Is there a big difference to write your first functions as below because
I am not familiar with yield keyword?
def skip_blanks(lines):
"""Remove leading and trailing whitespace, ignore blank lines."""
return [line.strip() in lines if line.strip()]
Yes, a *big* difference in the true sense of the word. Your code (assuming
you meant to write "... for line in ..." ) evaluates the entire list
comprehension before returning from the call. Steven's code returns a
generator that only handles one line (or a couple of empty lines) at a
time. So, assuming that this runs against a large file, Steven's code uses
only a constant amount of memory, compared to the whole file in your case,
and is likely also a lot faster than your code as it involves less looping.
Stefan
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