split_var: Split numeric variables into smaller groups

Description

Recode numeric variables into equal sized groups, i.e. a variable is cut into a smaller number of groups at specific cut points.

Usage

split_var(x, groupcount, as.num = FALSE, val.labels = NULL, var.label = NULL, inclusive = FALSE, suffix = "_g")

Arguments

A variable, data frame or list-object.

groupcount

The new number of groups that x should be split into.

as.num

Logical; if TRUE, the recoded variable will be returned as numeric vector. If FALSE, a factor is returned.

val.labels

Optional character vector, to set value label attributes of recoded variable (see set_labels). If NULL (default), no value labels will be set. Value labels can also be directly defined in the recodes-syntax, see 'Details'.

var.label

Optional string, to set variable label attribute for the returned variable (see set_label). If NULL (default), variable label attribute of x will be used (if present). If empty, variable label attributes will be removed.

inclusive

Logical; if TRUE, cut point value are included in the preceeding group. This may be necessary if cutting a vector into groups does not define proper ("equal sized") group sizes. See 'Note' and 'Examples'.

suffix

String value, will be appended to variable (column) names of x, if x is a data frame. If x is not a data frame, this argument will be ignored. The default value to suffix column names in a data frame depends on the function call:

recoded variables (rec()) will be suffixed with "_r"
dichotomized variables (dicho()) will be suffixed with "_d"
grouped variables (split_var()) will be suffixed with "_g"

Value

A grouped variable with equal sized groups.

Details

split_var splits a variable into equal sized groups, where the amount of groups depends on the groupcount-argument. Thus, this functions cuts a variable into groups at the specified quantiles. By contrast, group_var recodes a variable into groups, where groups have the same value range (e.g., from 1-5, 6-10, 11-15 etc.).

Examples

Run this code

data(efc)
# non-grouped
table(efc$neg_c_7)

# split into 3 groups
table(split_var(efc$neg_c_7, 3))


# original
table(efc$e42dep)

# two groups, non-inclusive cut-point
# vector split leads to unequal group sizes
table(split_var(efc$e42dep, 2))

# two groups, inclusive cut-point
# group sizes are equal
table(split_var(efc$e42dep, 2, inclusive = TRUE))

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