| expression {base} | R Documentation |
Unevaluated Expressions
Description
Creates or tests for objects of mode "expression".
Usage
expression(...)
is.expression(x)
as.expression(x)
Arguments
... |
valid R expressions. |
x |
an arbitrary R object. |
Value
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.
See Also
call,
eval,
function.
Further,
text and
legend
for plotting math expressions.
Examples
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)