Return numpy array from python to Lazarus

[Chemistza74]

Hi,

I've recently started playing around with P4D in Lazarus/FPC. I'm trying to read a numpy array created in python back in to FPC. The python code which I have in SynEdit1:

import numpy as np py_array = np.zeros(10) for i in range (10): py_array[i]=i 

My attempt at the FPC code below to extract py_array is based on FPC Demo35:

const N = 10; type PIntArray = ^TIntArray; TIntArray = array[0..N - 1] of NativeInt; procedure TForm1.Button1Click(Sender: TObject); var np_arr: PPyObject; PyBuffer: Py_buffer; I:integer; res:int64; begin self.PythonEngine1.ExecStrings(self.SynEdit1.lines); np_arr := ExtractPythonObjectFrom(MainModule.py_array); PythonEngine1.PyObject_GetBuffer(np_arr, @PyBuffer, PyBUF_CONTIG); PythonEngine1.CheckError; try for I := 0 to N - 1 do res:= PIntArray(PyBuffer.buf)^[I]; self.ListBox1.Items.Add(inttostr(res)); finally PythonEngine1.PyBuffer_Release(@PyBuffer); end; end; 

However, when I run this, I only end up with a single, random number in ListBox1. Any suggestions on how to resolve this would be greatly appreciated!

[pyscripter]

If you run this code in PyScripter

import numpy as np py_array = np.zeros(10) for i in range (10): py_array[i]=i print(py_array)

The output is:

[0. 1. 2. 3. 4. 5. 6. 7. 8. 9.]

Notice that the values are floating point and you try to read them as Integers.

I think if you change your code to:

import numpy as np py_array = np.zeros(10, dtype= np.int32) for i in range (10): py_array[i]=i

or simpler:

import numpy as np py_array = np.array(range(10))

it should work.