expandRows {splitstackshape}

Expand the Rows of a Dataset

Description

Expands (replicates) the rows of a data.frame or data.table, either by a fixed number, a specified vector, or a value contained in one of the columns in the source data.frame or data.table.

Usage

expandRows(dataset, count, count.is.col = TRUE, drop = TRUE)

Arguments

dataset

The input data.frame or data.table.

count

The numeric vector of counts OR the column from the dataset that contains the count data. If count is a single digit, it is assumed that all rows should be repeated by this amount.

count.is.col

Logical. Is the count value a column from the input dataset? Defaults to TRUE.

drop

Logical. If count.is.col = TRUE, should the "count" column be dropped from the result? Defaults to TRUE.

Value

A data.frame or data.table, depending on the input.

Author(s)

Ananda Mahto

References

http://stackoverflow.com/a/19519828/1270695

Examples

mydf <- data.frame(x = c("a", "b", "q"), 
                   y = c("c", "d", "r"), 
                   count = c(2, 5, 3))
library(data.table)
DT <- as.data.table(mydf)
mydf
expandRows(mydf, "count")
expandRows(DT, "count", drop = FALSE)
expandRows(mydf, count = 3) ## This takes values from the third column!
expandRows(mydf, count = 3, count.is.col = FALSE)
expandRows(mydf, count = c(1, 5, 9), count.is.col = FALSE)
expandRows(DT, count = c(1, 5, 9), count.is.col = FALSE)