Calculate percent change — pct

Calculate percent change from one vector (x) to another (y)

pct_change(x, y, denominator = 100)

Arguments

x	[`numeric()`] Baseline value(s)
y	[`numeric()`] Comparison value(s)
denominator	[`numeric()`] Default to 100 for percent (ex: 20%). Specify denominator = 1 to get percent change as a decimal (ex: 0.20).

Value

[numeric()]
Percent change from x to y: denominator * (y - x) / x

Examples

# vectors
pct_change(x = c(10, 11, 12), y = c(100, 22, 18))
#> [1] 900 100  50

# data.table
library(data.table)
dt <- data.table(
  x = c(10, 11, 12),
  y = c(100, 22, 18)
)
dt[, change := pct_change(x, y)]
#>     x   y change
#> 1: 10 100    900
#> 2: 11  22    100
#> 3: 12  18     50

# percent change within one data.table column
dt <- data.table(
  year = c(2000, 2001, 2002),
  val = c(10, 11, 12)
)
dt[, change := pct_change(x = shift(val), y = val)]
#>    year val    change
#> 1: 2000  10        NA
#> 2: 2001  11 10.000000
#> 3: 2002  12  9.090909