[R] locating intervals

halldor bjornsson
Tue, 08 Aug 2006 16:47:18 -0000

Hi ,

I have two sorted vectors X and Xi, where the range of Xi lies within the
range of X.

For an element in Xi, I want to find the neigbouring data in X, e.g. find an
index ix
so that for element number k, then
X[ix[k]] < X[k] < X[ix[k] +1]  # also OK with "<=" on either
one, but not
both

This is easy to code by looping over the data in X,Xi, but I suspect there
may be a faster and more elegant way to do this in R.

In Python (Numeric) the same can be achieved with
ix=Numeric.searchsorted(X[1:-1],Xi),
which is quite compact.

So, does anyone know of a corresponding R  call that can achive the same?

Sincerely,
Halldór

--
Halldor Bjornsson
Weatherservice R & D
Icelandic Met. Office

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