On Sep 27, 2006, at 12:23 PM, Vince Teachout wrote:
What I recall being frustrating was THINKING I understood slicing,
and then trying to predict what the result of a particular slice
would be. Something along the lines of "foobar[1,2] should give me
the letter 'A'", and then getting back a P, or a OOBAR or
something. (that's widely paraphrasing from something I recall
from several months ago, not a real example)
You might be tripping over one of the other differences between Fox
and Python: one-based vs. zero-based indexing. The first element in a
Fox array is referenced as myArray[1], whereas in Python it is myList
[0].
Here's a quick example using a string, which internally is a list of
characters. Let's say I have:
x = "Vince Teachout"
I can reference any single character using its zero-based position:
x[0] => "V"
x[3] => "c"
What's really cool is relative indexes. For example, let's say I
want the last character of the string:
x[-1] = "t"
x[-4] = "h"
I can reference any range of characters via a slice, where the first
number is the starting element's index, and the second is the index
of the element that the slice will go up to, but *not* include. So I
would have:
x[1:4] => start at element 1 and go up to but not include element 4
=> "inc"
x[:5] => start at element zero (implied) and go up but not include
element 5 => "Vince"
Relative indexes also work with slices:
x[-7:-3] => "each"
x[-7:] => "eachout"
There are so many possibilities, including steps, reversing, etc.,
but this should give you the basics.
-- Ed Leafe
-- http://leafe.com
-- http://dabodev.com
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