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Create a within-group lagged difference variable

Source: R/create_variables.R
group_diff.Rd

Create a within-group lagged difference variable

Usage

group_diff(
  dat,
  project,
  group,
  sort_by,
  value,
  name = "group_diff",
  lag = 1,
  create_group_ID = FALSE,
  drop_total_col = FALSE
)

Arguments

dat

Primary data frame over which to apply function. Table in FishSET database should contain the string `MainDataTable`.

project

String, project name.

group

String, the grouping variable(s) to sum value by. Used to create the "group_total" variable.

sort_by

String, a date variable to order `MainDataTable` by.

value

String, the value variable used to calculate lagged difference. Must be numeric.

name

String, the name for the new variable. Defaults to "group_diff".

lag

Integer, adjusts lag length. Defaults to 1.

create_group_ID

Logical, whether to create a group ID variable using ID_var. Defaults to FALSE.

drop_total_col

Logical, whether to remove the "group_total" variable created to calculate percentage. Defaults to FALSE.

Details

group_diff creates a grouped lagged difference variable. value is first summed by the variable(s) in group, then the difference within-group is calculated. The "group_total" variable gives the total value by group and can be dropped by setting drop_total_col = TRUE. A group ID column can be created using the variables in group by setting create_group_ID = TRUE.

Examples

if (FALSE) {
group_diff(pollockMainDataTable, "pollock", group = c("PERMIT", "TRIP_ID"),
           sort_by = "HAUL_DATE", value = "HAUL")
}