# NOT RUN { require(stats) formals(lm) ## If you just want the names of the arguments, use formalArgs instead. names(formals(lm)) methods:: formalArgs(lm) # same ## formals returns a pairlist. Arguments with no default have type symbol (aka name). str(formals(lm)) ## formals returns NULL for primitive functions. Use it in combination with ## args for this case. is.primitive(`+`) formals(`+`) formals(args(`+`)) ## You can overwrite the formal arguments of a function (though this is ## advanced, dangerous coding). f <- function(x) a + b formals(f) <- alist(a = , b = 3) f # function(a, b = 3) a + b f(2) # result = 5 # }
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