2c-chessNp.py

""" Demonstrate fundamental programming elements
by creating a checker board, 8 by 8 fields,
field size is configurable, same width and height

Again, the basic algorith is like before, but this time
we use a more advanced data structure provided by a external library
The library "numerical python" (numpy) is imported with the statement
#import numpy as np
and it's functions are called as "np.function_name()"

We use the "array" data type to realize a 2D matrix, representing
the checker board. The 2D matrix is similar to the list of lists but
offers additional operations e.g. on the entire dataset which we use
in the future

"""

# numpy is a helper library
import numpy as np

# function to make one linear segment of a pattern
def segment(width, color):
    """ put <width> items of color in a row"""
    # initialize a new list as a numpy array
    seg = np.empty(width) #
    # add items with a FOR LOOP
    for i in range(width):
        seg[i] = color
    # return the list
    return seg

# the main function
def main():
    """create a checker board pattern using a function"""

    # constants
    fields = 4
    fieldWidth = 4

    # variables
    row = 0
    column = 0
    # set color to 0
    color = 0
    # create the board matrix
    board = np.empty((fields*fieldWidth,fields*fieldWidth))
    while row < fields*fieldWidth and column < fields*fieldWidth:
        # append the segment
        board[row,column:column+fieldWidth] = segment(fieldWidth,color)
        # invert color
        color = 1 if color == 0 else 0
        # increment column
        column = column + fieldWidth if column < fieldWidth*(fields-1) else 0
        # increment row if column = 0
        row = row + 1 if column == 0 else row
        # invert color again if new row and end of field
        if column == 0 and row % fieldWidth == 0 :
            color = 1 if color == 0 else 0


    print("Checker board")
    print(board)


# call the main function
if __name__ == "__main__":
    main()