How to insert pawns on the board?

Question

I created board, but I've confused with pawns.

board = [[(x,y) for x in range(1,9)] for y in range(1,9)]
for k in range(len(board)):
    print('| |' * len(board))

I want to see something like that:

| || || || || || || || |
|P||P||P||P||P||P||P||P|
| || || || || || || || |
| || || || || || || || |
| || || || || || || || |
| || || || || || || || |
|P||P||P||P||P||P||P||P|
| || || || || || || || |

But which way can I choose to put pawns on the boards? Should I use double for loops to check if coordinates equal or exist alternative way to?

def pawn():
    coordinates = board[1][1]
    return coordinates

for i in range(len(board)):
    for j in range(8):
        if board[i][j] == pawn():
           print('|P|' * len(board))
        else:
           print('| |')

Answer 1

Something like that could work:

import numpy as np
board = np.empty((8,8)).tolist()
for k in range(len(board)):
    if k == 1 or k ==6:
        board[k]= ['|p|','|p|','|p|','|p|','|p|','|p|','|p|','|p|']
    else:
        board[k]= ['|x|','|x|','|x|','|x|','|x|','|x|','|x|','|x|']
[print(''.join(b)) for b in board ]

but I'm not sure if it is what you wanted. In that case board is a 2D matrix which is shape like the board. if it is for chess, you need a 'P' for white and a 'p' for black.

Answer 2

The initial position of pawns is row 2 and 7. You can check the for loop index and set their positions. Something like:

board = [[(x,y) for x in range(1,9)] for y in range(1,9)]
pawnRows = [1, 6]  # 0 based index

for k in range(len(board)):
    if k in pawnRows:
        print('|P|' * len(board))
    else:
        print('|X|' * len(board))

Answer 3

Making it more general, you can use an array or pandas.DataFrame to remember the state of the board

Data definition

Setting up the pieces

piece = collections.namedtuple('piece', ('value', 'mark'))
EMPTY = piece(0, '|X|')
PAWN = piece(1, '|P|')
pieces = {p.value: p for p in (EMPTY, PAWN)}

You can define as much pieces as you want, and even give the separate colours

Defining the board

boardsize = (8,8)
board = pd.DataFrame(data=[[1] * boardsize[0]] * boardsize[1]) * EMPTY.value

Setting up the pieces

pawn_positions = [(1, 1), (3, 4), (7, 6)]

for pawn in pawn_positions:
    board.loc[pawn] = PAWN.value

Results in something like this

    0   1   2   3   4   5   6   7
0   0   0   0   0   0   0   0   0
1   0   1   0   0   0   0   0   0
2   0   0   0   0   0   0   0   0
3   0   0   0   0   1   0   0   0
4   0   0   0   0   0   0   0   0
5   0   0   0   0   0   0   0   0
6   0   0   0   0   0   0   0   0
7   0   0   0   0   0   0   1   0

Printing the board with marks

for row_nr, row in board.applymap(lambda x: pieces[x].mark).iterrows():
    print(''.join(row) + '\n')

gives

|X||X||X||X||X||X||X||X|
|X||P||X||X||X||X||X||X|
|X||X||X||X||X||X||X||X|
|X||X||X||X||P||X||X||X|
|X||X||X||X||X||X||X||X|
|X||X||X||X||X||X||X||X|
|X||X||X||X||X||X||X||X|
|X||X||X||X||X||X||P||X|