parsing from text file to graph (python)

This function parses a grid like the one you've given into a set of nodes (stored as a pair of coordinates in the original grid), and a dict of edges (mapping each node to a list of nodes that are adjacent to it). This is a very easy-to-use representation for the graph, and you should have no trouble coding the maze search using it. The code uses the idea that the structure of the maze is described by just the edges (- and |), and that the grid is double-line spaced horizontally and vertically. A square with no edges into or out of it will not appear in the graph.

import collections

def parse_grid(grid):
    edges = collections.defaultdict(list)
    for i in xrange(len(grid)):
        for j in xrange(len(grid[i])):
            if grid[i][j] == '-':
                edges[i, j - 2].append((i, j + 2))
                edges[i, j + 2].append((i, j - 2))
            if grid[i][j] == '|':
                edges[i - 2, j].append((i + 2,j))
                edges[i + 2, j].append((i - 2,j))
    nodes = set()
    for e in edges.iterkeys():
        nodes.add(e)
    return nodes, edges

grid = """\
o . o . o . o
-   -   .   -
o . o . o | o 
.   -   .   .
o | o . o . o
.   -   .   -
o . o . o . o"""
print parse_grid(grid.split('\n'))

The implementation would depend on how you want to represent the graph in Python.

I'm creating an edge list

edgelist = []
y=0
for line in file:

    chars = [char for char in line.split(" ") if len(char)]
    x = 0

    if ('|' in chars):
        y+=1
        for char in chars:
            if char == 'o'
                x+=1
            elif char == '.'
                edgelist.append([(x,y),(x+1,y)])
    else:
        for char in chars:
            x+=1
            if char == '.'
                edges.append([(y,x),(y,x+1))

this should work, but i havn't tested it yet, going to do that now.

"""
maze1.txt

4 4
o . o . o . o
-   -   .   -
o . o . o | o
.   -   .   .
o | o . o . o
.   -   .   -
o . o . o . o
"""

readfile = open('maze1.txt', 'r')
line = readfile.readline()
rowcount, colcount = [int(elem) for elem in line.strip().split(' ')]
rights = []
downs = []
chars =      ('o', '   ', '.', '-', '|', '')
translated = ('o', '   ', '.', '-', '|', '') # if needed, could be int or method

while line:
    line = readfile.readline()
    if chars[0] in line:
        for elem in line.strip().split(chars[0])[1:]:
            rights.append(translated[chars.index(elem.strip())])
    else:
        for elem in line.strip().split(chars[1])[:colcount]:
            downs.append(translated[chars.index(elem.strip())])


readfile.close()

for i, elem in enumerate(rights):
    print elem, divmod(i, colcount)
print "##"
for i, elem in enumerate(downs):
    print elem, divmod(i, colcount)