How can I reorder the rows of a matrix, data.frame or vector according to another one
25,502
Solution 1
test2 <- test2[rownames(test1),,drop=FALSE]
Solution 2
After fixing your code snipped to actually generate what your example shows (hint: test1
had names a,b,c,d,e; you meant a,d,c,b,1 as it shows now), this was easier thanks to match()
:
R> test2[match(row.names(test2), row.names(test1)),1,drop=FALSE]
[,1]
a 10
d 7
c 8
b 9
e 6
R>
They key here is that match()
does what you want:
R> match(row.names(test2), row.names(test1))
[1] 5 2 3 4 1
Author by
John
Updated on March 04, 2020Comments
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John about 4 years
test1 <- as.matrix(c(1, 2, 3, 4, 5)) row.names(test1) <- c("a", "d", "c", "b", "e") test2 <- as.matrix(c(6, 7, 8, 9, 10)) row.names(test2) <- c("e", "d", "c", "b", "a") test1 [,1] a 1 d 2 c 3 b 4 e 5 test2 [,1] e 6 d 7 c 8 b 9 a 10
How can I reorder test2 so that the rows are in the same order as test1? e.g.
test2 [,1] a 10 d 7 c 8 b 9 e 6
I tried to use the reorder function with: reorder (test1, test2) but I could not figure out the correct syntax. I see that reorder takes a vector, and I'm here using a matrix. My real data has one character vector and another as a data.frame. I figured that the data structure would not matter too much for this example above, I just need help with the syntax and can adapt it to my real problem.
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chimpsarehungry over 11 yearsWhy does this not work for my data? I want to do
test2[match(test2$column, test1$column),1,drop=FALSE]
because what i am matching by is the values of the columns not the row.names -
chimpsarehungry over 11 yearsWhy does this not work for my data? I want to do test2[match(test2$column, test1$column),1,drop=FALSE] because what i am matching by is the values of the columns not the row.names