try this:

> a <- c(5, 10, 13, 19, 23)

>

> b <- c(1, 4, 7, 9, 15)

> # use outer for comparison

> z <- outer(a, b, ">")

> # use rowSums to get the indices (may have to check for zero)

> b[rowSums(z)]

[1] 4 9 9 15 15

>

On Wed, Oct 20, 2010 at 10:41 PM, bruclee <

[hidden email]> wrote:

>

> I am trying to compare two sorted vectors, all elements in both vectors are

> not duplicated. Ex.

> a = c[5, 10, 13, 19, 23]

> b = c[1, 4, 7, 9, 15]

> For each element in a, i need find the max element in b which is smaller

> than it, so the short answer will look like [4, 9, 9, 15, 15].

> I dont want to use any loop since my real project contains element in

> millions. Is there any way to speed up my operation? Many Thanks.

> --

> View this message in context:

http://r.789695.n4.nabble.com/Help-Using-vectorization-method-for-vectors-comparision-tp3004952p3004952.html> Sent from the R help mailing list archive at Nabble.com.

>

> ______________________________________________

>

[hidden email] mailing list

>

https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide

http://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code.

>

--

Jim Holtman

Cincinnati, OH

+1 513 646 9390

What is the problem that you are trying to solve?

______________________________________________

[hidden email] mailing list

https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide

http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.