Group a numerical variable into an n-level factor

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Description

GroupNumeric converts a numerical variable x into a factor variable with n groups for categorical association analysis.

Usage

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GroupNumeric(x, n = NULL, groupNames = NULL, orderedFactor = FALSE,
  style = "quantile", ...)

Arguments

x

Numeric vector to be grouped.

n

Integer number of groups; if NULL (the default), the number of groups will be inferred from the groupNames parameter.

groupNames

Character vector of names for the levels of the factor variable created; if NULL (the default), the default names from R's cut function will be used.

orderedFactor

Logical, specifying whether the factor returned is ordered or not; default is FALSE.

style

Character string, passed to the classIntervals function from the classInt package as its style parameter (see help file for the classInterval function for details); default is "quantile".

...

Optional parameters passed to the classIntervals function from the classInt package.

Details

This function uses the classIntervals function from the classInt package to compute the breakpoints that define the groups. The style parameter is passed to the classIntervals function to specify the grouping method. Note that some methods may return a different number of groups than that requested via the n parameter. If groupNames is specified consistently with n, this different number of returned groups will cause an error. The recommended approach in this case is to either change the style parameter or to re-run without groupNames specified.

Value

Factor variable with n distinct levels, named according to groupNames (if specified).

Author(s)

Ron Pearson