[R] how to get values within a threshold

[arun]

Hi,
You could try:
val1<- c(0.854400, 1.648465, 1.829830, 1.874704, 7.670915, 7.673585, 7.722619)
thresh1<- c(1,3,5,7,9)
rowSums(t(replicate(length(thresh1),val1))<= thresh1)
#[1] 1 4 4 4 7

#using ?sapply() could be shortened
sapply(thresh1,function(x) {sum(val1<x)})
#[1] 1 4 4 4 7


A.K.




----- Original Message -----
From: Zhang Weiwu <zhangweiwu at realss.com>
To: r-help at r-project.org
Cc: 
Sent: Friday, September 13, 2013 6:13 AM
Subject: [R] how to get values within a threshold


input:

    > values
    [1] 0.854400 1.648465 1.829830 1.874704 7.670915 7.673585 7.722619

    > thresholds
    [1] 1 3 5 7 9

expected output:

    [1] 1 4 4 4 7

That is, need a vector of indexes of the maximum value below the threshold.

e.g.
First  element is "1", because value[1] is the largest below threshold "1".
Second element is "4", because value[4] is the largest below threshold "3".

The way I do it is:

> sapply(1:length(threshold), function(x) { length(values[values < threshold[x]])})
[1] 1 4 4 4 7

It just seem to me too long and stupid to be like R. Is it already the best way?

Somehow I feel which() was designed for a purpose like this, but I couldn't 
figure out a way to apply which here.

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