sjmisc (version 2.2.0)

group_var: Recode numeric variables into equal-ranged groups

Description

Recode numeric variables into equal ranged, grouped factors, i.e. a variable is cut into a smaller number of groups, where each group has the same value range, and create the related value labels.

Usage

group_var(x, groupsize = 5, as.num = TRUE, right.interval = FALSE, groupcount = 30)
group_labels(x, groupsize = 5, right.interval = FALSE, groupcount = 30)

Arguments

x

A variable, data frame or list-object.

groupsize

Numeric; group-size, i.e. the range for grouping. By default, for each 5 categories of x a new group is defined, i.e. groupsize=5. Use groupsize = "auto" to automatically resize a variable into a maximum of 30 groups (which is the ggplot-default grouping when plotting histograms). Use groupcount to determine the amount of groups.

as.num

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

right.interval

Logical; if TRUE, grouping starts with the lower bound of groupsize. See 'Details'.

groupcount

Sets the maximum number of groups that are defined when auto-grouping is on (groupsize="auto"). Default is 30. If groupsize is not set to "auto", this argument will be ignored.

Value

• For group_var, a grouped variable, either as numeric or as factor (see paramter as.num).
• For group_label, a string vector or a list of string vectors containing labels based on the grouped categories of x, formatted as "from lower bound to upper bound", e.g. "10-19" "20-29" "30-39" etc. See 'Examples'.

Details

If groupsize is set to a specific value, the variable is recoded into several groups, where each group has a maximum range of groupsize. Hence, the amount of groups differ depending on the range of x. If groupsize = "auto", the variable is recoded into a maximum of groupcount groups. Hence, independent from the range of x, always the same amount of groups are created, so the range within each group differs (depending on x's range). right.interval determins which boundary values to include when grouping is done. If TRUE, grouping starts with the lower bound of groupsize. For example, having a variable ranging from 50 to 80, groups cover the ranges from 50-54, 55-59, 60-64 etc. If FALSE (default), grouping starts with the upper bound of groupsize. In this case, groups cover the ranges from 46-50, 51-55, 56-60, 61-65 etc. Note: This will cover a range from 46-50 as first group, even if values from 46 to 49 are not present. See 'Examples'. If you want to split a variable into a certain amount of equal sized groups (instead of having groups where values have all the same range), use the split_var function!

See Also

split_var to split variables into equal sized groups, group_str for grouping string vectors or rec_pattern and rec for another convenbient way of recoding variables into smaller groups.

Examples

age <- abs(round(rnorm(100, 65, 20)))
age.grp <- group_var(age, 10)
hist(age)
hist(age.grp)

age.grpvar <- group_labels(age, 10)
table(age.grp)
print(age.grpvar)

# histogram with EUROFAMCARE sample dataset
# variable not grouped
data(efc)
hist(efc$e17age, main = get_label(efc$e17age))

# bar plot with EUROFAMCARE sample dataset
# grouped variable
ageGrp <- group_var(efc$e17age)
ageGrpLab <- group_labels(efc$e17age)
barplot(table(ageGrp), main = get_label(efc$e17age), names.arg = ageGrpLab)

# within a pipe-chain
library(dplyr)
efc %>% select(e17age, c12hour, c160age) %>% group_var(groupsize = 20)

# create vector with values from 50 to 80
dummy <- round(runif(200, 50, 80))
# labels with grouping starting at lower bound
group_labels(dummy)
# labels with grouping startint at upper bound
group_labels(dummy, right.interval = TRUE)