data.set manipulation



Manipulation of Data Sets

Like data frames, data.set objects have subset, unique, cbind, rbind, merge methods defined for them.

The semantics are basically the same as the methods defined for data frames in the base package, with the only difference that the return values are data.set objects. In fact, the methods described here are front-ends to the corresponding methods for data frames, which are constructed such that the "extra" information attached to variables within data.set objects, that is, to item objects.

# S4 method for data.set
subset(x, …)

# S4 method for data.set unique(x, incomparables = FALSE, …)

# S3 method for data.set cbind(…, deparse.level = 1)

# S3 method for data.set rbind(…, deparse.level = 1)

# S4 method for data.set,data.set merge(x,y, …)

# S4 method for data.set,data.frame merge(x,y, …)

# S4 method for data.frame,data.set merge(x,y, …)


data.set objects. On of the arguments to merge may also be an object coercable into a data frame and the result still is a data.set object.

for subset: a logical vector of the same length as the number of rows of the data.set and, optionally, a vector of variable names (tagged as select); for unique: further arguments, ignored; for cbind, rbind: objects coercable into data frames, with at least one being a data.set object; for merge: further arguments such as arguments tagged with by, by.x, by.y, etc. that specify the variables by which to merge the data sets of data frames x and y.


a vector of values that cannot be compared. See unique.


an argument retained for reasons of compatibility of the default methods of cbind and rbind.

  • subset,data.set-method
  • unique,data.set-method
  • merge,data.set,data.set-method
  • merge,data.set,data.frame-method
  • merge,data.frame,data.set-method
ds1 <- data.set(
      a = rep(1:3,5),
      b = rep(1:5,each=3)
ds2 <- data.set(
      a = c(3:1,3,3),
      b = 1:5

ds1 <- within(ds1,{
      description(a) <- "Example variable 'a'"
      description(b) <- "Example variable 'b'"

ds2 <- within(ds2,{
      description(a) <- "Example variable 'a'"
      description(b) <- "Example variable 'b'"

str(ds3 <- rbind(ds1,ds2))

ds3 <- within(ds1,{
        c <- a
        d <- b
        description(c) <- "Copy of variable 'a'"
        description(d) <- "Copy of variable 'b'"
str(ds4 <- cbind(ds1,ds3))

ds5 <- data.set(
        c = 1:3,
        d = c(1,1,2)
ds5 <- within(ds5,{
      description(c) <- "Example variable 'c'"
      description(d) <- "Example variable 'd'"
str(ds6 <- merge(ds1,ds5,by.x="a",by.y="c"))

# Note that the attributes of the left-hand variables
# have priority.
# }
Documentation reproduced from package memisc, version, License: GPL-2

Community examples

Looks like there are no examples yet.