DataCombine (version 0.1.13)

PercChange: Calculate the percentage change from a specified lag, including withing group

Description

Calculate the percentage change from a specified lag, including withing group

Usage

PercChange(data, Var, GroupVar = NULL, NewVar = NULL, slideBy = -1,
  type = "percent")

Arguments

data

a data frame object.

Var

a character string naming the variable you would like to find the percentage change for.

GroupVar

a character string naming the variable grouping the units within which the percentage change will be found for (i.e. countries in a time series). If GroupVar = NULL then the entire data frame is treated as one unit.

NewVar

a character string specifying the name for the new variable to place the percentage change in.

slideBy

numeric value specifying how many rows (time units) to make the percentage change comparison for. Positive values shift the data up--lead the data.

type

character string set at either percent for percentages or proportion to find proportions.

Value

• a data frame

Details

Finds the percentage or proportion change for over a given time period either within groups of data or the whole data frame. Important: the data must be in time order and, if groups are used, group-time order.

Examples

# Create fake data frame
A <- c(1, 1, 1, 1, 1, 2, 2, 2, 2, 2)
B <- c(1:10)
Data <- data.frame(A, B)

# Find percentage change from two periods before
Out <- PercChange(Data, Var = 'B', GroupVar = NULL,
         type = 'proportion', NewVar = 'PercentChange', slideBy = -2)

Out