expression(...) is.expression(expr) as.expression(expr)
expression
returns a vector of mode "expression"
containing its arguments as unevaluated ``calls''.
is.expression
returns TRUE
if expr
is
an expression object and FALSE
otherwise.
as.expression
attempts to coerce its argument
into an expression object.
call
, eval
, function
.
Further, text
and legend
for plotting math
expressions.length(ex1 <- expression(1+ 0:9))# 1 ex1 eval(ex1)# 1:10 length(ex3 <- expression(u,v, 1+ 0:9))# 3 mode(ex3 [3]) # expression mode(ex3[[3]])# call rm(ex3)