Python-for-Delphi-Developers

& 64 bits
Linux
MacOS
Mostly non-visual components
Can be used in console applications
Lazarus/FPC support

for heavy data-analytics work)
Python 2 vs. Python 3
32-bits vs. 64-bits
Download and run the installer
Installation options (location, for all users)
Install python packages you are planning to use (can be done later)
Use the python package installer (pip) from the command prompt
eg. > pip install numpy

the Github repository into a directory (e.g., D:\Components\P4D).
Start RAD Studio.
Add the source subdirectory (e.g., D:\Components\P4D\Source) to the IDE's library path for the targets you are planning to use.
Open and install the Python4Delphi package specific to the IDE being used. For Delphi Sydney and later it can be found in the Packages\Delphi\Delphi 10.4+ directory. For earlier versions use the package in the Packages\Delphi\Delphi 10.3- directory.

Note:  The package is Design & Runtime together

Memo
Source Code:

procedure TForm1.btnRunClick(Sender: TObject);
begin
GetPythonEngine.ExecString(UTF8Encode(sePythonCode.Text));
end;

<= 1:
return False
q = math.floor(math.sqrt(n))
for i in range(2, q + 1):
if (n % i == 0):
return False
return True

Delphi
function IsPrime(x: Integer): Boolean;
begin
if (x <= 1) then Exit(False);
var q := Floor(Sqrt(x));
for var i := 2 to q do
if (x mod i = 0) then
Exit(False);
Exit(True);
end;

1):
if is_prime(i):
res += 1
return res
def test():
max_n = 1000000
print(f'Number of primes between 0 and {max_n} = {count_primes(max_n)}')
def main():
print(f'Elapsed time: {Timer(stmt=test).timeit(1)} secs')
if __name__ == '__main__':
main()

USING TPYTHONMODULE (II)

Output
Number of primes between 0 and 1000000 = 78498
Elapsed time: 3.4528134000000037 secs

to the PythonEngine
ModuleName: delphi_module
Implement python function delphi_is_prime by writing a Delphi event

procedure TForm1.PythonModuleEvents0Execute(Sender: TObject; PSelf, Args: PPyObject; var Result: PPyObject);
Var
N: Integer;
begin
with GetPythonEngine do
if PyArg_ParseTuple(Args, 'i:delphi_is_prime',@N) <> 0 then
begin
if IsPrime(N) then
Result := PPyObject(Py_True)
else
Result := PPyObject(Py_False);
Py_INCREF(Result);
end else
Result := nil;
end;

range(2, max_n + 1):
if delphi_is_prime(i):
res += 1
return res

USING TPYTHONMODULE (IV)

Output
Number of primes between 0 and 1000000 = 78498
Elapsed time: 0.3073742000000017 secs

10x + improvement!

But hold on. Delphi can do something python can’t do easily: Use threads and multiple CPU cores

:= 0;
TParallel.&For(2, MaxN, procedure(i: integer)
begin
if IsPrime(i) then
AtomicIncrement(Count);
end);
Result := Count;
end;

Output
Number of primes between 0 and 1000000 = 78498
Elapsed time: 0.04709590000000219 secs

70x + improvement!

Python
from delphi_module import delphi_count_primes
from timeit import Timer
import math
def test():
max_n = 1000000
print(f'Number of primes between 0 and {max_n} = {delphi_count_primes(max_n)}')

using RTTI and cusomised wrapping of common Delphi objects.
Add a TPyDelphiWrapper on the form and link it to a PythonModule.
In this demo we will wrap a Delphi record containing a class function.

type
TDelphiFunctions = record
class function count_primes(MaxN: integer): integer; static;
end;
var
DelphiFunctions: TDelphiFunctions;

procedure TForm1.FormCreate(Sender: TObject);
begin
var Py := PyDelphiWrapper.WrapRecord(@DelphiFunctions,
TRttiContext.Create.GetType(TypeInfo(TDelphiFunctions))
as TRttiStructuredType);
PythonModule.SetVar('delphi_functions', Py);
PythonEngine.Py_DecRef(Py);
end;

forms
Subclass Forms (and other Delphi types)
Add python Form event handlers
Use customized wrapping of common RTL and VCL objects
Common Dialogs
StringLists
Exception handling

worlds
P4D makes it very easy to integrate Python into Delphi applications in RAD way
Expose Delphi function, objects, records and types to Python using low or high-level interfaces
In a future webinar we will cover
Using python libraries and objects in Delphi code (VarPyth)
Python based data analytics in Delphi applications
Creating Python extension modules using Delphi
Python GUI development using the VCL