Python problem Write a program that shall display a hollow d

Python problem!

Write a program that shall display a hollow diamond of stars with N rows and N columns, where N is a variable initialized with an odd positive number. An example of a diamond with N=7 is shown below:

Solution

# The diamond size l = 9 # Initialize first row; this will create a list with a # single element, the first row containing a single star rows = [\'*\'] # Add half of the rows; we loop over the odd numbers from # 1 to l, and then append a star followed by `i` spaces and # again a star. Note that range will not include `l` itself. for i in range(1, l, 2): rows.append(\'*\' + \' \' * i + \'*\') # Mirror the rows and append; we get all but the last row # (the middle row) from the list, and inverse it (using # `[::-1]`) and add that to the original list. Now we have # all the rows we need. Print it to see what\'s inside. rows += rows[:-1][::-1] # center-align each row, and join them # We first define a function that does nothing else than # centering whatever it gets to `l` characters. This will # add the spaces we need around the stars align = lambda x: (\'{:^%s}\' % l).format(x) # And then we apply that function to all rows using `map` # and then join the rows by a line break. diamond = \'\ \'.join(map(align, rows)) # and print print(diamond)