Python Interop with Julia

Julia is extremely versatile when it comes to interop with other programming languages and environments such as C, Python, R and Java.

# Calling Python in Julia

In Julia, Python codes can be called via the PyCall interface package that is readily available for install from the general registry.

Spin up a Julia REPL for the repository and hit ] to switch it to Package mode and install the PyCall package as such.

(workspace) pkg> add PyCall

After that, import PyCall in any of the Julia file and the Python codes can be defined and executed by using the py"" wrapper.

using PyCall

py"print('Hello from Python')" # Julia only allow strings to be enclosed with double quotes

To get its return value, just assign the Python block directly to a Julia variable.

total = py"100 + 100"

typeof(total) |> println
total |> println

# Working With Python Packages

To use a Python library such as those from the PyPi repository, the package needs to be installed to the correct Python interpreter that PyCall is using.

To find out where the interpreter is, run the following code in Julia to find out its exact location.

PyCall.python |> println

After that, cd into the directory (make sure Python.exe is present) and install any desired packages with the following command.

python -m pip install <your-package>

After the successful installation, it is now ready to be used within Julia codes. The package installed for demonstration here is called cleantext that is used for sanitizing strings.

To import the installed Python package, use the pyimport function and call its function with a dot notation as such.

py_clean = pyimport("cleantext")

py_clean.clean("h€ello") |> println

# Defining a Python Function

Python function can be defined within a multiline block of py"" as shown below.

py"""
from cleantext import clean

def custom_clean(x: str):
    return clean(f'cleaned text: {x}')
"""

The newly defined Python function can be invoked within the same py"" block again.

py"custom_clean"("»Yóù àré     rïght <3!«") |> println