by-split function

Split a data frame

Split a dataframe according to the levels of variables in the dataframe. The variables to split by can be given as a formula or as a character vector.

split_by(data, formula, drop = TRUE)

splitBy(formula, data = parent.frame(), drop = TRUE)

## S3 method for class 'splitByData'
head(x, n = 6L, ...)

## S3 method for class 'splitByData'
tail(x, n = 6L, ...)

Arguments

• data: A data frame

• formula: Variables to split data frame by, as as.quoted

  variables, a formula or character vector.

• drop: Logical indicating if levels that do not occur should be dropped. Deprecated; levels that do not occur are ignored.

• x: An object.

• n: A single integer. If positive or zero, size for the resulting object: number of elements for a vector (including lists), rows for a matrix or data frame or lines for a function. If negative, all but the "n" last/first number of elements of "x".

• ...: Arguments to be passed to or from other methods.

Returns

A list of dataframes.

Examples

data(dietox, package="doBy")
splitBy(formula = ~Evit + Cu, data = dietox)
splitBy(formula = c("Evit", "Cu"), data = dietox)

splitBy(~Treatment + Type, data=CO2)
splitBy(c("Treatment", "Type"), data=CO2)

x <- splitBy(~Treatment, data=CO2)
head(x)
tail(x)

See Also

orderBy, order_by, summaryBy, summary_by, transformBy, transform_by

Author(s)

Søren Højsgaard, sorenh@math.aau.dk