How to extract data?
james.holtman at convergys.com wrote:
By 'ignore', can we delete those from the list of data? I would then assume that if you have a sequence of +0+0+ that you would want the last "+" for the increase of three. If that is the case, then do a 'diff' and delete the entries that are 0. Then create a new 'diff' and then use 'rle' to see what the length of the sequences are:
x <- c(1,2,2,3,3,4,3,3,2,2,2,1) x
[1] 1 2 2 3 3 4 3 3 2 2 2 1
x.d <- diff(x) x.d
[1] 1 0 1 0 1 -1 0 -1 0 0 -1
x.new <- x[c(x.d,1) != 0] x.new
[1] 1 2 3 4 3 2 1
x.d1 <- diff(x.new) x.d1
[1] 1 1 1 -1 -1 -1
rle(x.d1)
Run Length Encoding lengths: int [1:2] 3 3 values : num [1:2] 1 -1
Additionally, if there are differences are > 1, you might want apply sign() before rle(). Uwe Ligges
you can check the results of 'rle' to determine where the changes are.
__________________________________________________________
James Holtman "What is the problem you are trying to solve?"
Executive Technical Consultant -- Office of Technology, Convergys
james.holtman at convergys.com
+1 (513) 723-2929
ebashi
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r-help-bounces at stat.m Subject: [R] How to extract data?
ath.ethz.ch
11/23/2004 15:54
I appreciate if anyone can help me,
I have a table as follow,
rate
DATE VALUE
1 1997-01-10 5.30
2 1997-01-17 5.30
3 1997-01-24 5.28
4 1997-01-31 5.30
5 1997-02-07 5.29
6 1997-02-14 5.26
7 1997-02-21 5.24
8 1997-02-28 5.26
9 1997-03-07 5.30
10 1997-03-14 5.30
. ...... ...
. ...... ...
. ...... ...
I want to extract the DATE(s) on which the VALUE has
already dropped twice and the DATE(s) that VALUE has
already increased for three times,( ignore where
VALUE(i+1)-VALUE(i)=0),I try to use diff() function,
however that works only for one increase or decrease.
Sincerely,
Sean
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