Grid data sturcture

[HaNcOoK]

Hi everybody,
Im pretty new (or u can say that completely new) to python and i try to learn from the very basic. I try to create grid data structure from array. Here i have some code, would you mind to look at it and give me an instruction:

import math

class Grid(object):
def __init__(self, width = 10, height = 10):
self.width = width
self.height = height
self.size = size
self.grid = []
cell_value = 0

.....

then i got stucked, i would like to print out this array and then save it into text file! i look some place and it gave me this

import numpy as np
x = np.arange(20).reshape((4,5))
np.savetxt('test.txt', x)

but i dont know how to print it then save it into text file
if i have value with coordinate (x,y) later, can i change it in text file? and how?

thank you very much, it will be helpful
hancook

[TrustyTony]

If you want to change the file you read the values, do changes in memory and save to file again.

import math

class Grid(list):
    def __init__(self, cell_value=0, width = 10, height = 10):
       list.__init__(self, [[cell_value for _ in range(width)]
                        for _ in range(height)])
       self.cell_value = cell_value
       
    def save(self, fname):
        with open(fname, 'w') as out:
            for row in self:
                out.write(', '.join(str(column)for column in row))
                out.write('\n')

    def __str__(self):
        res = '[\n'
        for row in self:
            res += '     ' + str(row) + ',\n'
        return res[:-2] +'\n]'

    __repr__ = __str__

grid = Grid()
print grid
grid [7][8] = 4
print grid
grid.save('grid.txt')