subset(x, ...) subset.default(x, subset, ...) subset.matrix(x, subset, select, drop = FALSE, ...) subset.data.frame(x, subset, select, drop = FALSE, ...)
x | the object to subset. |
subset | a logical expression. Indicates which elements (from a vector or a matrix) or which rows (from a data frame) to subset. |
select | an expression that indicates which columns to select. It is used only for a matrix or a data frame. |
drop | a logical flag that is passed to the index operator [ to determine the class and shape of the extracted result. See the drop details in Subscript for more information. |
... | further arguments to be passed to or from other methods. |
x <- runif(20) subset(x, x > 0.3 & x < 0.7)z <- matrix(1:16, nrow=4) subset(z, z[,3]==10) # [,1] [,2] [,3] [,4] # [1,] 2 6 10 14 subset(z, z[,3]==10, drop=TRUE) # [1] 2 6 10 14
y <- matrix(c(2, 4, 3, 9, 21, NA, 6, 4, 9, 10, NA, 7), nrow = 3) dimnames(y)<-list(c("r1","r2","r3"), c("c1","c2","c3","c4")) subset(y, y[,4] > 8) subset(y, !is.na(y[,4]),select = c(2:4))
df <- data.frame(aa=1:10, bb=LETTERS[1:10], cc=letters[rep(1:5,2)]) subset(df, cc=="b") # aa bb cc # 2 2 B b # 7 7 G b subset(df, cc=="b" & aa>5) # aa bb cc # 7 7 G b subset(df, cc=="b" & aa>5, select=c("aa","cc")) # aa cc # 7 7 b