one
one(x)
Get the multiplicative identity element for the type of x
(x
can also specify the type itself). For matrices, returns an identity matrix of the appropriate size and type.
Examples
julia> one(10)
1
julia> foo = zeros(Int8, (2,2));
julia> one(foo)
2x2 Array{Int8,2}:
1 0
0 1
julia> complexNumber = complex(1, 1); # 1 + 1im
julia> one(complexNumber)
1 + 0im
-
Get the multiplicative identity element for a numeric type:
julia> one(3) 1 julia> one(3.5) 1.0
In this example,
one
returns the multiplicative identity element for the given numeric values. -
Get the multiplicative identity element for a custom type:
julia> struct MyType end julia> one(MyType()) MyType()
Here,
one
returns the multiplicative identity element for a custom typeMyType
. -
Get the identity matrix for a matrix type:
julia> A = [1 2; 3 4]; julia> one(A) 2×2 Matrix{Int64}: 1 0 0 1
When given a matrix
A
,one
returns an identity matrix of the appropriate size and type.
Common mistake example:
julia> one("abc")
ERROR: MethodError: no method matching one(::String)
In this example, one
is called with a string argument. However, one
is not defined for strings, so it raises a MethodError
. It's important to note that one
is typically used with numeric types or matrices.
See Also
User Contributed Notes
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