Find the variable names in a formula

A reaction formula has reactants and products, separated by <=>, with reactants on the left and products on the right (by convention). Each of those is a plus separated list of reacting compounds and modifiers, with optional coefficients, e.g.: A + 2 B <=> AB2

Usage

match.names(chrv)

Arguments

chrv

a character vector as returned by parse.formula

Value

coefficients, as a vector

Details

Once the formula is split into left and right side, this function determines the names. For the above example, this function returns c("A","B") for the left side and "AB2" for the right side.

Examples

lapply(uqsa:::parse.formula("A + 2*B <=> AB2"),uqsa:::match.names)
#> $reactants
#> [1] "A"   "2*B"
#> 
#> $products
#> [1] "AB2"
#> 
lapply(uqsa:::parse.formula("A + 2*B <=> AB2"),uqsa:::match.names)
#> $reactants
#> [1] "A"   "2*B"
#> 
#> $products
#> [1] "AB2"
#>