Introduction
Python4Delphi (P4D)
Other components utilising Python4Delphi Python binding
Python Environments
Lightweight Python Wrappers
Delphi4Python

Python language in Delphi

Introduction

Delphi 11 now has ability to run Python scripts via Python4Delphi which has a wrapper for the Python dll
SynEdit is an optional library that provides syntax highlighting and proper indention behaviors if you want to allow users to edit Python code in your application.

Python4Delphi (P4D)

let's you run Python scripts from Delphi
can create new Python modules
can create Python extensions as DLLs

if you get error “cannot load python DLL”:
- ensure you have compiled your Delphi app with same version (32bit or 64bit compile) as the Python on your computer - you should generally be using 64 bit!

Displaying plots as well as text outputs from running Python scripts

as plots are SVG files from matplotlib you need to install svgiconimagelist components into Delphi
optoinally you can also install Microsoft Edge Webview 2 to display results in Delphi TEdgeViewer - but this method is not shown here
https://en.delphipraxis.net/topic/4648-window-hooking/
https://github.com/pyscripter/python4delphi/blob/master/Tutorials/Webinar%20II/Python%20for%20Delphi%20Developers%20II.pdf
add to your form:
- initialization section on the Form source file to prevent module import errors:
- ```
initialization
  MaskFPUExceptions(True);
  
```
- scripting control:
  - SynPythonSyn
  - SynEdit - set highlighter to SynPythonSyn
  - SynEditPythonBehaviour1 - set editor to SynEdit
- text output component
  - eg. a memo component
- plot output component
  - SVGIconImage
- Python4Delphi components
  - PythonGUIInputOutput - link it to a memo component to display text outputs
  - PythonEngine - set IO to the PythonGUIInputOutput
  - PythonModule - name it delphi_module, set engine to PythonEngine
  - PyWrapper - set engine to PythonEngine and set Module to PythonModule
- Button to run script
  - OnClick:
  - ```
  var Script: string;
  begin
  Script := SynEdit1.Text;
  GetPythonEngine.ExecString(Utf8Encode(Script));
  end;
   
```
- Form Create event:
  - ```
  begin
    var Py := PyDelphiWrapper.Wrap(SVGIconImage, soReference);
    PythonModule.SetVar('svg_image', Py);
    GetPythonEngine.Py_DECREF(Py);
  end;
```
then your Python script must be modified as follows (or you can automatically add these in code to the script in the OnButtonClick event:

append:

from delphi_module import svg_image
from io import StringIO
figfile = StringIO()
plt.savefig(figfile, format='svg')
figdata_svg = figfile.getvalue()
svg_image.SvgText = figdata_svg

remember - any new script you run will just will act like a new kernel cell, so variables and imports from prior runs will remain in memory!
you have to close app and restart it to create a new clean kernel

TPythonEngine

UseLatestVersion - automatically detects latest registered version on your computer
Python DLL name - I set this to python311.dll (default was python37.dll)
DLL path - I set this to my environment path as per Anaconda
Registered version
IO - link to a TPythonGUIInputOutput component
run Python script via: PythonEngine1.ExecStrings( memo1.Lines );
To avoid module import FloatDivideZero errors, type PythonEngine.MaskFPUExceptions(True); prior to calling PythonEngine1.ExecStrings( memo1.Lines ); - preferably in the Form initialization section

TPythonGUIInputOutput

Output - link to a TMemo

TPythonModule

create a Python module using Delphi code which can be called from Python using a low level approach
- Delphi maths may be 100x faster than python maths eg. in determining if an integer is a prime
Engine - link to TPythonEngine
ModuleName eg. Delphi_maths_module
then use the event handler to run Delphi code and send Python Objects - but you will also need to call reference counter for Python as Python reference counts objects PyINCREF(result) where result is a PyObject
- see https://learndelphi.org/everything-you-need-to-know-about-the-python4delphi-library/

TPyWrapper

high level approach to use Delphi code which can be called from Python - uses RTTI, no need for python reference count issues at each function level
link to TPyModule

TPythonType

create a Python type class in Delphi
Engine - link to TPythonEngine
TypeName
Module - link to TPythonModule
Services
etc

TPythonDelphiVar

Engine - link to TPythonEngine
Module
VarName

TPythonInputOutput

receive python input
RawOutput true/false
UnicodeIO true/false

Other components utilising Python4Delphi Python binding

Keras4Delphi
- https://github.com/KoRiF/Keras4Delphi
- a high-level neural networks API, written in Delphi's Object Pascal with Python Binding and capable of running on top of TensorFlow.
- Supports both convolutional networks and recurrent networks, as well as combinations of the two. Runs seamlessly on CPU and GPU.
- uses python4delphi and partial conversion of NumPy4Delphi
- requires Python 3, keras, nump, tensorflow to be installed

Python Environments

failed to install

Lightweight Python Wrappers

wrappers based on P4D allow import of Python modules into Delphi components
works with Python Environments

Delphi4Python

allows using Delphi VCL and FMX form designers to create a Python GUI and export them for use in Python

Table of Contents

Python language in Delphi

Introduction

Python4Delphi (P4D)

Displaying plots as well as text outputs from running Python scripts

TPythonEngine

TPythonGUIInputOutput

TPythonModule

TPyWrapper

TPythonType

TPythonDelphiVar

TPythonInputOutput

Other components utilising Python4Delphi Python binding

Python Environments

Lightweight Python Wrappers

Delphi4Python