[R] Line similarity

arun smartpink111 at yahoo.com
Tue Apr 30 23:40:58 CEST 2013

You could also do:
v<- read.table(text="
Name Year_1_value Year_2_value Year_3_value
A 1 2 3
B 2 7 19
C 3 4 2
D 10 7 6
E 4 4 5
F NA 3 6
v2<- v

v$Beta<-sapply(split(v1,v1$Name),function(x) coef(lm(Year~time,data=x))[2])

v$Growing<- v$Beta>0
#  Name Year_1 Year_2 Year_3 Beta Growing
#1    A      1      2      3  1.0    TRUE
#2    B      2      7     19  8.5    TRUE
#3    C      3      4      2 -0.5   FALSE
#4    D     10      7      6 -2.0   FALSE
#5    E      4      4      5  0.5    TRUE
#6    F     NA      3      6  3.0    TRUE

v2$Beta<- ldply(dlply(v1,.(Name),lm, formula=Year~time),coef)[,3]
v2$Growing<- v2$Beta>0
#[1] TRUE


----- Original Message -----
From: "Satsangi, Vivek (GE Capital)" <Vivek.Satsangi at ge.com>
To: "r-help at r-project.org" <r-help at r-project.org>
Sent: Tuesday, April 30, 2013 3:57 PM
Subject: [R] Line similarity


                This is probably a "help me google this properly, please"-type of question.

                In TIBCO Spotfire, there is a procedure called "line similarity". I use this to determine which observations show a growing, stable or declining pattern... sort of like a mini-regression on the time-line for each observation.

                So of the input is something like this:

Name Year_1_value Year_2_value Year_3_value
A 1 2 3
B 2 7 19
C 3 4 2
D 10 7 6
E 4 4 5
F NA 3 6

Then the desired output is as follows:
A Growing
B Growing
C Stable
D Declining
E Stable
F Growing (or NA is also fine)

                The data can also be unstacked, i.e. the three years could be separate rows if necessary.
                Is there a package for R that implements something like the above? I can obviously try do a set of simple regressions to classify the rows, but I want to gain from the thoughts and learnings of others who may have taken the time to implement a package.
                I tried searching with the words "line similarity" or its variants to no avail.

                Thanks in advance for your pointers!

Vivek Satsangi
GE Capital

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