[fixed] method overload using np.savetxt

[paul18fr]

Hi all,

In the following example, i'm trying to write numpy arrays having different sizes in a same file. The goal is to use inheritance capability of the "Write" method. Nonetheless only the last np.savetxt appears in the "text.txt" file: what am i doing wrong?

Note i recently started to use oop

Thanks for any hint

# -*- coding: utf-8 -*-

import numpy as np
import os

# mother class
class Point:
    
    def __init__(self):
        pass

    @staticmethod
    def Write(file, M):
        '''
            To write the numpy array into an active file
        '''
        np.savetxt(file, M, fmt = '%u')
            

# child class 
class Point2D(Point):
    def __init__(self):
        super().__init__() 
        
    # overloading
    @staticmethod
    def Write(file, M):
        '''
            To write the numpy array into an active file
        '''
        np.savetxt(file, M, fmt = 'id=%u, x=%.4e, y=%.4e')


# grandchild class    
class Point3D(Point2D):
    def __init__(self):
        super().__init__() 
        
    # overloading
    @staticmethod
    def Write(file, M):
        '''
            To write the numpy array into an active file
        '''
        np.savetxt(file, M, fmt = 'id=%u, x=%.4e, y=%.4e, z=%.4e')

    

if __name__ == '__main__':
    
    Path = os.getcwd()
    myFile = 'test.txt'
    n = 5
    
    ##
    i = np.arange(1, n+1).reshape(-1, 1)
    
    M_2D = np.hstack( (i, np.random.random( (n, 2))) )
    p_2D = Point2D()
    # print(f"P2D = \n{M_2D}")
    
    M_3D = np.hstack( (M_2D, np.random.random( (n, 1))) )
    p_3D = Point3D()
    # print(f"P3D = \n{M_3D}")
    
    
    with open (Path + '/' + myFile, 'w') as f:
        p_2D.Write(file = myFile, M = M_2D)
        p_3D.Write(file = myFile, M = M_3D)
        
    with open (Path + '/' + myFile[:-4] + '_2.txt', 'w') as f:
        np.savetxt(f, M_2D, fmt = 'id=%u, x=%.4e, y=%.4e')
        np.savetxt(f, M_3D, fmt = 'id=%u, x=%.4e, y=%.4e, z=%.4e')

text.txt file:

Output:
id=1, x=2.3987e-01, y=4.6717e-01, z=8.1817e-02
id=2, x=5.1711e-01, y=9.4611e-01, z=8.9698e-01
id=3, x=8.9620e-01, y=1.5750e-01, z=8.1349e-01
id=4, x=9.4836e-01, y=5.3436e-01, z=6.0168e-01
id=5, x=1.6820e-01, y=9.6548e-01, z=2.3962e-01

text_2.txt file:

Output:
id=1, x=2.3987e-01, y=4.6717e-01
id=2, x=5.1711e-01, y=9.4611e-01
id=3, x=8.9620e-01, y=1.5750e-01
id=4, x=9.4836e-01, y=5.3436e-01
id=5, x=1.6820e-01, y=9.6548e-01
id=1, x=2.3987e-01, y=4.6717e-01, z=8.1817e-02
id=2, x=5.1711e-01, y=9.4611e-01, z=8.9698e-01
id=3, x=8.9620e-01, y=1.5750e-01, z=8.1349e-01
id=4, x=9.4836e-01, y=5.3436e-01, z=6.0168e-01
id=5, x=1.6820e-01, y=9.6548e-01, z=2.3962e-01

[paul18fr]

how stupid i am ...

    with open (Path + '/' + myFile, 'w') as f:
        p_2D.Write(file = f, M = M_2D)
        p_3D.Write(file = f, M = M_3D)

[snippsat]

A simpler way to write your code without using method overloading.
Since the only difference between the Write methods in your classes is the format string used in np.savetxt.
Then can refactor your code to use a single Write method in the base class and pass the format string as an attribute or parameter.

import numpy as np
import os

class Point:
    def __init__(self, fmt='%u'):
        self.fmt = fmt
    def Write(self, file, M):
        '''Writes the numpy array using a specified format.'''
        np.savetxt(file, M, fmt=self.fmt)

class Point2D(Point):
    def __init__(self):
        super().__init__(fmt='id=%u, x=%.4e, y=%.4e')

class Point3D(Point):
    def __init__(self):
        super().__init__(fmt='id=%u, x=%.4e, y=%.4e, z=%.4e')

if __name__ == '__main__':
    Path = os.getcwd()
    myFile = 'test.txt'
    n = 5
    # Generate data and make point objects
    r_shape = np.arange(1, n+1).reshape(-1, 1)
    M_2D = np.hstack((r_shape, np.random.random((n, 2))))
    M_3D = np.hstack((M_2D, np.random.random((n, 1))))
    p_2D = Point2D()
    p_3D = Point3D()

    # Write data to file
    with open(os.path.join(Path, myFile), 'w') as f:
        p_2D.Write(file=f, M=M_2D)
        p_3D.Write(file=f, M=M_3D)

The classes are not maintaining any state and only using them to write data with different formats,might not need classes at all.
A simple function would suffice.

import numpy as np
import os

def write_points(file, M, fmt):
    '''Writes the numpy array using a specified format.'''
    np.savetxt(file, M, fmt=fmt)

if __name__ == '__main__':
    Path = os.getcwd()
    myFile = 'test1.txt'
    n = 5
    r_shape = np.arange(1, n+1).reshape(-1, 1)
    M_2D = np.hstack((r_shape, np.random.random((n, 2))))
    M_3D = np.hstack((M_2D, np.random.random((n, 1))))

    # Write data to file
    with open(os.path.join(Path, myFile), 'w') as f:
        write_points(file=f, M=M_2D, fmt='id=%u, x=%.4e, y=%.4e')
        write_points(file=f, M=M_3D, fmt='id=%u, x=%.4e, y=%.4e, z=%.4e')

[paul18fr]

@snippsat: thanks for the first (interesting) hint .

Paul