PythonCall not working in Jupyter Notebook in VSCode

[AquaPore]

Affects: PythonCall

Describe the bug
The PythonCall is not working in Jupyter Notebook in VScode.

The answer to fib(100) problem see below is nothing. Nevertheless the code works beautifully in REPL.

Many thanks for any help you may provide.

Your system
Please provide detailed information about your system:

• The operating system: Windows 10
• The version of Julia, Python, PythonCall, JuliaCall: latest

Additional context

using PythonCall

fib(x) = pyexec("""
def fib(n):
	a, b = 0, 1
	while a < n:
		print(a, end=' ')
		a, b = b, a+b
	print()
fib(y)
""", Main, (y=x,))

print(fib(10))

[cjdoris]

pyexec always returns nothing when called like that, it would have been the same in the REPL. In the REPL it probably just looked like it returned something because you print the answer inside fib.

To extract values you can pass a named tuple type specifying what to keep, like

pyexec(@NamedTuple{ans::BigInt}, """
.......
ans = fib(y)
""", Main, (y=x,))

Also see the @pyexec macro which makes this a bit easier.

[AquaPore]

Hi Christopher,

A great thanks for your kind help.

Thanks for your suggestion by using pyexec, nevertheless, the following code still does not work as I get the following error message:

cannot convert this Python 'NoneType' to a Julia 'BigInt'

Did I do something wrong. Also I am confused why you suggest to use BigInt as I taught Float64 would be more appropriate.

Many thanks for your kind help,
Joseph

function PYTHON_2_JULIA(x)

fib(x) = pyexec(@NamedTuple{ans::BigInt},"""
def fib(n):
    a, b = 0, 1
    while a < n:
        print(a, end=' ')
        a, b = b, a+b
    print()
ans = fib(y)
""", Main, (y=x,))

C = fib(x)

println(C)

return C
end

[AquaPore]

I found an alternative solution by using as you suggested by using ** PythonCall.@PYEXEC**

function PYTHON_2_JULIA(P_Int, P_Float, P_String, P_Vector)

    PythonCall.@pyexec """
        def PYTHON_2_JULIA(P_Int, P_Float, P_String, P_Vector):
            P_Int1 = P_Int + 1
            P_Float1 = P_Float * 2.0
            P_String1 = P_String + P_String 
            P_Vector1 = P_Vector + P_Vector
            return P_Int1, P_Float1, P_String1, P_Vector1
        """=> PYTHON_2_JULIA

    P_Int1, P_Float1, P_String1, P_Vector1 = PythonCall.pyconvert(Any, PYTHON_2_JULIA(P_Int, P_Float, P_String, P_Vector))

return P_Int1, P_Float1, P_String1, P_Vector1
end

To run it:

P_Int=1; P_Float=2.0; P_String=3; P_Vector = [1.0, 2.0, 3.0, 4.0]
P_Int1, P_Float1, P_String1, P_Vector1 = .PYTHON_2_JULIA(P_Int, P_Float, P_String, P_Vector)

@show P_Int1, P_Float1, P_String1, P_Vector1

P_Vector1[1]

This gives as expected

(2, 4.0, 6, [2.0, 4.0, 6.0, 8.0])
2.0

[cjdoris]

Glad it's working now, I'll close the issue as resolved.

BTW the reason the previous fib wasn't working is because it didn't actually return anything.

[AquaPore]

Thanks @cjdoris , the idea is to wrap up some pyflwdir python package. Would you know how to call for e.g. numpy package into the example?

Thanks for any help you may provide.