By function

Apply a Function to a Data Frame Split by Factors

By(x, INDICES, FUN, COLUMNS, array = FALSE, ...)

Arguments

• x: Data frame
• INDICES: Indices (vector or list of indices, vector of column names, or formula of column names)
• FUN: A function to be applied to data frame subsets of 'data'.
• COLUMNS: (Optional) subset of columns of x to work on
• array: if TRUE an array/matrix is always returned
• ...: Additional arguments to lower-level functions

Details

Simple wrapper of the 'by' function

Examples

By(datasets::CO2,~Treatment+Type,colMeans,~conc)
By(datasets::CO2,~Treatment+Type,colMeans,~conc+uptake)

Author(s)

Klaus K. Holst