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Calculate year-over-year growth for a numeric column

compute_fastchange.Rd

Computes the year-over-year growth rate for a numeric column in a dataset. The function ensures a complete sequence of years between the minimum and maximum in the date column, fills in any missing years, and calculates the growth rate using lagged values.

Usage

compute_fastchange(data, col, date_col)

Arguments

data

A dataset.

col

A numeric column (either unquoted or as a string) for which the year-over-year growth rate will be calculated.

date_col

A date or numeric column (either unquoted or as a string) used to order the data and define the time sequence (typically a year column).

Value

A dataset with:

  • The completed date_col sequence.

  • A new column named "growth_<col>" containing the year-over-year growth rates.

The returned object will match the class of the input data.

Details

  • Missing years in the sequence are added automatically.

  • Missing values in col result in NA for the corresponding growth rate.

  • The first observation (or any row where the lag is missing) will have NA.

Examples

library(data.table)
#> 
#> Attaching package: ‘data.table’
#> The following object is masked from ‘package:base’:
#> 
#>     %notin%

dt <- data.table::data.table(
  year = c(2020, 2021, 2023),
  gdp = c(100, 110, 130)
)

# Using strings
compute_fastchange(dt, "gdp", "year")
#> Key: <year>
#>     year   gdp gdp_growth
#>    <int> <num>      <num>
#> 1:  2020   100         NA
#> 2:  2021   110        0.1
#> 3:  2022    NA         NA
#> 4:  2023   130         NA