Conversion to Python
Conversion Rules
The following table specifies the conversion rules used whenever converting a Julia object to a Python object.
From Julia, this occurs explicitly with Py(x)
or implicitly when passing Julia objects as the argument to a Python function. To avoid this automatic conversion, the user can convert objects explicitly, such as by calling pylist
or pydict
.
From Python, this occurs when converting the return value of a Julia function.
From | To |
---|---|
Any Python object type (Py , PyList , etc.) | itself |
Nothing | None |
Bool | bool |
Integer | int |
Rational{<:Integer} | fractions.Fraction |
Float64 , Float32 , Float16 | float |
Complex{Float64} , Complex{Float32} , Complex{Float16} | complex |
AbstractString , AbstractChar | str |
Base.CodeUnits{UInt8} (e.g. b"example" ) | bytes |
Tuple , Pair | tuple |
AbstractRange{<:Integer} | range |
Dates.Date | datetime.date |
Dates.Time | datetime.time |
Dates.DateTime | datetime.datetime |
Dates.Second , Dates.Millisecond , Dates.Microsecond , Dates.Nanosecond | datetime.timedelta |
Number | juliacall.NumberValue , juliacall.ComplexValue , etc. |
AbstractArray | juliacall.ArrayValue , juliacall.VectorValue |
AbstractDict | juliacall.DictValue |
AbstractSet | juliacall.SetValue |
IO | juliacall.BufferedIOValue |
Module | juliacall.ModuleValue |
Type | juliacall.TypeValue |
Anything else | juliacall.AnyValue |
See here for an explanation of the juliacall.*Value
wrapper types.
Custom rules
You may define a new conversion rule for your new type T
by overloading Py(::T)
.
If T
is a wrapper type (such as PyList
) where Py(x)
simply returns the stored Python object, then also define ispy(::T) = true
.
PythonCall.ispy
— Functionispy(x)
True if x
is a Python object.
This includes Py
and Python wrapper types such as PyList
.
Alternatively, if you define a wrapper type (a subtype of juliacall.AnyValue
) then you may instead define pyjltype(::T)
to be that type.
PythonCall.pyjltype
— Functionpyjltype(x)
The subtype of juliacall.AnyValue
which the Julia object x
is wrapped as by pyjl(x)
.
Overload pyjltype(::T)
to define a custom conversion for your type T
.