[R] finding the intersection of two vectors
Data Analytics Corp.
walt at dataanalyticscorp.com
Wed Jul 6 22:43:56 CEST 2011
Hi,
Suppose I have two vectors, not necessarily the same length (in fact,
they usually are different lengths): y.1 that has increasing values
between 0 and 1; y.2 that has decreasing values between 1.0 and 0. You
can picture these as being supply (= y.1) and demand (= y.2) curves from
economics. I typically plot these vectors on the same graph against a
common x variable, which happens to be price for what I do. The price
variable runs from, say, $0 to $25. When I plot y.1 and y.2, I've been
eye-balling a vertical line at a price point where y.1 intersects y.2.
I'm now tired of eye-balling a line through the intersection -- takes
too much time to get it right or just close enough. I can't figure out
how to find the price value at which the two curves intersect. Going
back to the economics interpretation, I want the price where supply
equals demand. Any suggestions as to how I can find that price point in
R? Any functions that help?
Thanks,
Walt
________________________
Walter R. Paczkowski, Ph.D.
Data Analytics Corp.
44 Hamilton Lane
Plainsboro, NJ 08536
________________________
(V) 609-936-8999
(F) 609-936-3733
walt at dataanalyticscorp.com
www.dataanalyticscorp.com
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