r - Pull specific rows -


let's have data frame looks this... 

city <- c("x","x","y","y","z","z","a","a") number <-c(1,2,3,4,5,6,7,8)  mat <- cbind.data.frame(city ,number)  "city"  "number"      x          1      x          2        y          3      y          4      z          5      z          6               7               8

now want able pull data for...

list <- c("x","y", "a")

and desired out come this... 

x  y  1  3 7  2  4 8

i tried using which(list%in%city) find indices pull data index not produce rows want.

update

make sure when using chris' answer data type "city" "chr" otherwise pop error message got before using "as.character" function.

i renamed variable list test, because list function name. can this, using data.table:

matdt <- as.data.table(mat) setkey(matdt, city) sapply(test, function(x) matdt[x, number])      x y [1,] 1 3 7 [2,] 2 4 8

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