> frame1
ID GROUP PROP_AREA
1 1 A 0.33
2 2 A 0.33
3 3 A 0.33
4 4 B 0.50
5 5 B 0.50
6 6 C 1.00
7 7 D 1.00
> frame2
GROUP VALUE1 VALUE2
1 A 10 5
2 B 20 10
3 C 30 15
4 D 40 20
>
> obj1 <- merge(x=frame1, y=frame2, by="GROUP")
> obj1$rval1 <- obj1$PROP_AREA * obj1$VALUE1
> obj1$rval2 <- obj1$PROP_AREA * obj1$VALUE2
> obj1
GROUP ID PROP_AREA VALUE1 VALUE2 rval1 rval2
1 A 1 0.33 10 5 3.3 1.65
2 A 2 0.33 10 5 3.3 1.65
3 A 3 0.33 10 5 3.3 1.65
4 B 4 0.50 20 10 10.0 5.00
5 B 5 0.50 20 10 10.0 5.00
6 C 6 1.00 30 15 30.0 15.00
7 D 7 1.00 40 20 40.0 20.00
>
> idx <- match(x=frame1$GROUP, table=frame2$GROUP)
> rval1 <- frame1["PROP_AREA"] * frame2[idx, "VALUE1"]
> rval2 <- frame1["PROP_AREA"] * frame2[idx, "VALUE2"]
> cbind("ID"=frame1[idx, "ID"], rval1, rval2)
ID PROP_AREA PROP_AREA
1 1 3.3 1.65
2 1 3.3 1.65
3 1 3.3 1.65
4 2 10.0 5.00
5 2 10.0 5.00
6 3 30.0 15.00
7 4 40.0 20.00
>
Is this what you are looking for? I hope this helps.
Chel Hee Lee
On 12/03/2014 03:14 PM, Brock Huntsman wrote:
I apologize if this is a relatively easy problem, but have been stuck on
this issue for a few days. I am attempting to combine values from 2
separate dataframes. Each dataframe contains a shared identifier (GROUP).
Dataframe 1 (3272 rows x 3 columns) further divides this shared grouping
factor into unique identifiers (ID), as well as contains the proportion of
the GROUP area of which the unique identifier consists (PROP_AREA).
Dataframe 2 (291 x 14976) in addition to consisting of the shared
identifier, also has numerous columns consisting of values (VALUE1,
VALUE2). I would like to multiply the PROP_AREA in dataframe 1 by each
value in dataframe 2 (VALUE1 through VALUE14976) based on the GROUP factor,
constructing a final dataframe of size 3272 x 14976. An example of the data
frames are as follows:
frame1:
ID
GROUP
PROP_AREA
1
A
0.33
2
A
0.33
3
A
0.33
4
B
0.50
5
B
0.50
6
C
1.00
7
D
1.00
frame2:
GROUP
VALUE1
VALUE2
A
10
5
B
20
10
C
30
15
D
40
20
Desired dataframe
frame3:
ID
VALUE1
VALUE2
1
3.3
1.65
2
3.3
1.65
3
3.3
1.65
4
10
5
5
10
5
6
30
15
7
40
20
I assume I would need to use the %in% function or if statements, but am
unsure how to write the code. I have attempted to construct a for loop with
an if statement, but have not been successful as of yet.
for(i in 1:nrow(frame1)) {
for(j in 2:ncol(frame2)) {
if (frame1$GROUP[i] == frame2$GROUP[i]) {
frame3[i,j+1] <- frame1$PROP_AREA[i]*frame2[i,j+1]
}
}
}
Any advice on suggested code or packages to read up on would be much
appreciated.
Brock
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
