Python - counting sign changes

Posted by dadashek on Stack Overflow See other posts from Stack Overflow or by dadashek
Published on 2010-05-29T22:42:54Z Indexed on 2010/05/29 22:52 UTC
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I have a list of numbers I am reading left to right. Anytime I encounter a sign change when reading the sequence I want to count it.

X = [-3,2,7,-4,1,-1,1,6,-1,0,-2,1] X = [-, +, +, -, +, -, +, +, -, -,-,+]

So, in this list there are 8 sign changes.

When Item [0] (in this case -3) is negative it is considered a sign change. Also, any 0 in the list is considered [-].

Any help would be greatly appreciated.

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