Kit wrote:
Thank you so much guys.
Just out of curiosity: can I do something like this to "square all
even numbers in the range 1-10"?
print [x^2 for x in range (1,11) if x % 2 == 0]
Or is there a better way of doing it? Thanks for the help, and I am
really appreciate your help.
That's a fine way to do it, although:
xrange is slightly more efficient than range for large
sets of values. (This isn't such a large set for it to matter.)
You can get range and xrange to count by two's, eliminating
the need for the "if" portion in this case.
The exponent operator is ** not ^, and x*x is more efficient than x**2.
So.
print [x**2 for x in xrange(1,11,2)]
Gary Herron
Kit.
On 1月19日, 上午12時30分, Steven D'Aprano <st...@remove-this-
cybersource.com.au> wrote:
On Mon, 18 Jan 2010 08:07:41 -0800, Kit wrote:
Hello Everyone, I am not sure if I have posted this question in a
correct board. Can anyone please teach me:
What is a list compression in Python?
Google "python list comprehension".
If Google is broken for you, try Yahoo, or any other search engine.
Would you mind give me some list compression examples?
Instead of this:
L = []
for x in range(10):
L.append(x**2)
you can write:
L = [x**2 for x in range(10)]
Instead of this example:
L = []
for x in range(10):
if x % 2 == 0:
L.append(x**2)
you can write:
L = [x**2 for x in range(10) if x % 2 == 0]
--
Steven
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