umx_aggregate: Convenient formula-based cross-tabs & built-in summary...

In umx: Structural Equation Modeling and Twin Modeling in R

Convenient formula-based cross-tabs & built-in summary functions

Description

A common task is preparing summary tables, aggregating over some grouping factor. Like mean and sd of age, by sex. R's aggregate() function is useful and powerful, allowing xtabs based on a formula.

umx_aggregate makes using it a bit easier. In particular, it has some common functions for summarizing data built-in, like "mean (sd)" (the default).

umx_aggregate(mpg ~ cyl, data = mtcars, what = "mean_sd")

cyl	mpg
4 (n = 11)	26.66 (4.51)
6 (n = 7)	19.74 (1.45)
8 (n = 14)	15.1 (2.56)

Usage

umx_aggregate(
  formula = DV ~ condition,
  data = df,
  what = c("mean_sd", "n"),
  digits = 2,
  report = c("markdown", "html", "txt"),
  output = c("table", "string")
)

Arguments

formula	The aggregation formula. e.g., DV ~ condition.
data	frame to aggregate (defaults to df for common case)
what	function to use. Default reports "mean (sd)".
digits	to round results to.
report	Format for the table: Default is markdown.
output	Format for the results: "table" (default) or "string".

Value

• table or character vector of formatted strings

References

https://github.com/tbates/umx, https://tbates.github.io

See Also

• umx_apply(), aggregate()

Other Reporting Functions: aic_weights(), plot.umx_GWAS(), umx, umxAPA(), umxFactorScores(), umxGetLatents(), umxGetManifests(), umxGetModel(), umxGetParameters(), umxParameters(), umx_time()

Examples

# =====================================
# = Basic use, compare with aggregate =
# =====================================
aggregate(mpg ~ cyl, FUN = mean, na.rm = TRUE, data = mtcars)
umx_aggregate(mpg ~ cyl, data = mtcars)

# =============================================
# = Use different (or user-defined) functions =
# =============================================
umx_aggregate(mpg ~ cyl, data = mtcars, what = "n")
umx_aggregate(mpg ~ cyl, data = mtcars, what = function(x){sum(!is.na(x))})

# turn off markdown
umx_aggregate(mpg ~ cyl, data = mtcars, report = "txt")

# =========================================================
# = More than one item on the left hand side (Table 1 style)=
# =========================================================
umx_aggregate(cbind(mpg, qsec) ~ cyl, data = mtcars, digits = 3)

# =========================
# = Output as a string    =
# =========================
umx_aggregate(mpg ~ cyl, data = mtcars, output = "string")

## Not run: 
umx_aggregate(cbind(moodAvg, mood) ~ condition, data = study1)

## End(Not run)

umx documentation built on Oct. 11, 2026, 5:07 p.m.