R provides a number of specialized objects. They are created (instantiated), used and referenced through variable (known as symbol).
The variable (symbol) references objects.
The symbols are themselves objects and has wide ranging effects.
R have some reserved variable (system variable)
> x=1
# Implicit printing of the variable
> x
[1] 1
# Explicit printing of the variable
> print(x)
The [1] indicates that x is of the vector class
> x+x
[1] 2
The type determine the internal storage and can be seen as the primitive type of R.
See R - (Datatype|Type|Storage Mode) of an object (typeof, mode)
The class properties permits R to have an object like behavior.
R supports several class (data structure) for an object:
And you can create yours.
All objects except the NULL object can have one or more attributes.
Common R objects attributes are:
Attributes of an object can be listed using the attributes() function.
# data.frame object
x=data.frame(a=1:4,b=1:4,c=1:4)
attributes(x)
$names
[1] "a" "b" "c"
$row.names
[1] 1 2 3 4
$class
[1] "data.frame"
The value of a specific attribute can be obtained using the attr() function (or NULL if the attribute is not defined).
For example,
# data.frame object
x=data.frame(a=1:4,b=1:4,c=1:4)
attr(x, "class")
[1] "data.frame"
newname <- oldname
rm(oldname)
List current objects (objects in the workspace)
ls()
ls shows you the variables
> x <- rnorm(50)
> y <- rnorm(x)
> ls()
[1] "x" "y"
rm(object)
# Delete all variables for the environment
rm(list = ls())
> rm(x, y)
> ls()
character(0)
newobject <- edit(object)
https://cran.r-project.org/web/packages/diffobj/README.html
apropos (or find) returns a character vector of all objects matching the text searched.
apropos("myObject")
Structure of an object
str(object)
# Open an editor and doesn't gives the possibility to change the definition
edit(object)
#
# Open an editor and gives the possibility to change the values.
fix(object)
View(object)
where object is an object that can be coerced to a data frame