Update README.md

Signed-off-by: David Rotermund <54365609+davrot@users.noreply.github.com>

matlab/python_used_by_matlab/README.md

@@ -53,7 +53,148 @@ ans =
 
 **Obviously you need to use your location for your Python installation.**
 
-
+## Python help
+
+```matlab
+>> py.help('int')
+Help on class int in module builtins:
+
+class int(object)
+ |  int([x]) -> integer
+ |  int(x, base=10) -> integer
+[...]
+```
+
+## Tuple and random number example
+
+We can crate a python tuple like this:
+
+```matlab
+>> py_dim = py.tuple({py.int(10), py.int(100)})
+
+py_dim = 
+
+  Python tuple with values:
+
+    (10, 100)
+
+    Use string, double or cell function to convert to a MATLAB array.
+```
+
+Now we can use numpy to generate random numbers:
+
+```matlab
+>> py_dim = py.tuple({py.int(10), py.int(100)})
+>> rng = py.numpy.random.default_rng();
+>> a = rng.random(py_dim);
+>> py.print(py.type(a))
+<class 'numpy.ndarray'>
+>> py.print(a.shape)
+(10, 100)
+>> py.print(a.dtype)
+float64
+>> whos
+>> whos
+  Name        Size            Bytes  Class                                   Attributes
+
+  a           1x1                 8  py.numpy.ndarray                                  
+  ans         1x1                 8  matlab.pyclient.PythonEnvironment                 
+  py_dim      1x2                 8  py.tuple                                          
+  rng         1x1                 8  py.numpy.random._generator.Generator    
+```
+
+Alternatively this is also possible:
+
+```matlab
+>> b = rng.random(cell({int32(10),int32(100)}));
+```
+
+## User defined Python modules
+
+Our very own Python function in the file **mtest_1.py**:
+
+```python
+import numpy as np
+
+def mysquared(input:np.ndarray) -> np.ndarray:
+    output = input**2
+    return output
+```
+
+Now Matlab allows us to do this:
+
+```matlab
+>> x = (1:1:10);
+>> x_np = py.numpy.array(x);
+>> y_np = py.mtest_1.mysquared(x_np);
+>> y = double(x_np).^2;
+>> sum(sum(abs(y-double(y_np))))
+
+ans =
+
+     0
+```
+
+If you change the py file, then you need to clean it from the memory via
+
+```matlab
+>> clear classes
+```
+
+## Save a numpy file with Matlab
+
+In Matlab we save data into numpy file:
+
+```matlab
+>> a = rand(100,10);
+>> a_np = py.numpy.array(a);
+>> py.numpy.save("test_1.npy",a_np);
+```
+
+Now we can load it into Python: 
+
+```python
+import numpy as np
+
+a = np.load("test_1.npy")
+
+print(type(a)) # --> <class 'numpy.ndarray'>
+print(a.shape) # --> (100, 10)
+print(a.dtype) # --> float64
+```
+
+## Loading a numpy file with Matlab
+
+Under Python we generate a file:
+
+```python
+import numpy as np
+
+myrng = np.random.default_rng()
+
+a = myrng.random((100, 10))
+np.save("test_2.npy", a)
+```
+
+And under Matlab we load it:
+
+>> a_np = py.numpy.load("test_2.npy");
+>> a = double(a_np);
+>> whos
+  Name        Size            Bytes  Class               Attributes
+
+  a         100x10             8000  double                        
+  a_np        1x1                 8  py.numpy.ndarray     
+
+## References 
+* [Access Python Modules from MATLAB - Getting Started](https://de.mathworks.com/help/matlab/matlab_external/create-object-from-python-class.html)
+* [Use Python str Variables in MATLAB](https://de.mathworks.com/help/matlab/matlab_external/pythonstrvariables.html)
+* [Use Python list Variables in MATLAB](https://de.mathworks.com/help/matlab/matlab_external/pythonlistvariables.html)
+* [Use Python tuple Variables in MATLAB](https://de.mathworks.com/help/matlab/matlab_external/pythontuplevariables.html)
+* [Use Python dict Variables in MATLAB](https://de.mathworks.com/help/matlab/matlab_external/python-dict-variables.html)
+* [Call User-Defined Python Module](https://de.mathworks.com/help/matlab/matlab_external/call-user-defined-custom-module.html)
+
+