expandCmd: Expand Mplus-style hyphenated variable ranges

In MplusAutomation: An R Package for Facilitating Large-Scale Latent Variable Analyses in Mplus

Expand Mplus-style hyphenated variable ranges

Description

Expands Mplus shorthand expressions that specify sequences of variables using hyphenated ranges (e.g., y1-y3) into the full list of variables (e.g., y1 y2 y3). This function also propagates suffixes from the right-hand token (e.g., @c, *c, or bare *) to every expanded variable (e.g., ⁠y1-y3@1⁠ -> ⁠y1@1 y2@1 y3@1⁠).

Usage

expandCmd(cmd, expand_numeric = FALSE)

Arguments

cmd	A single character string containing Mplus syntax to expand.
expand_numeric	Logical. If TRUE, expand pure numeric ranges (e.g., 1-3 -> ⁠1 2 3⁠) in list-like contexts. Default: FALSE.

Details

By default, the function does not expand pure numeric ranges (e.g., 1-3) to avoid confusion with arithmetic subtraction. If expand_numeric = TRUE, such ranges will be expanded when they appear in list-like contexts (whitespace/comma/semicolon/parentheses boundaries) and the line does not contain an equals sign (to avoid accidental expansion of arithmetic like d = 1 - 3).

Hyphens in MODEL CONSTRAINT expressions such as a = b1-b2 are explicitly protected and left untouched.

Value

A character string with hyphenated ranges expanded to explicit variable lists.

Examples

## Not run: 
expandCmd("y1-y3 y5-y6")
# "y1 y2 y3 y5 y6"

expandCmd("BY y1-y3@0.5;")
# "BY y1@0.5 y2@0.5 y3@0.5;"

expandCmd("z10-z12*2")
# "z10*2 z11*2 z12*2"

expandCmd("MODEL CONSTRAINT: a = b1-b2;")
# "MODEL CONSTRAINT: a = b1-b2;" (unchanged)

expandCmd("1 - 3", expand_numeric = TRUE)
# "1 2 3"

expandCmd("d = 1 - 3;", expand_numeric = TRUE)
# "d = 1 - 3;" (unchanged because of '=')

## End(Not run)

MplusAutomation documentation built on Sept. 9, 2025, 5:25 p.m.