id -- the identity map
Introductionid(x) evaluates and returns
x.
Call(s)id(x)
id(x1, x2...)
Parametersx, x1, x2, ... |
- | arbitrary MuPAD objects |
Returnsthe sequence of the input parameters.
Detailsid(x) evaluates and returns
x; id(x1, x2, ...) returns the
evaluated arguments as an expression
sequence; id() returns the void object
null().id is a function of the system kernel.
Example
1id returns the evaluated arguments:
>> a := 2: id(a + 2)
4
>> id(a, b, 4 + 2)
2, b, 6
id() returns null():
>> domtype(id())
DOM_NULL
>> delete a:
Example
2id is useful when working with functional
expressions:
>> f := 3*id + sin + 5*id^2 + exp@(-id^2): f(x)
2 2
3 x + sin(x) + 5 x + exp(- x )
>> D(f)
2
10 id + cos - 2 id exp@- id + 3
>> delete f: