How can I transform a string into a matrix

Question

I wrote a program that can find the way through a labyrinth. This program works with a matrix.

Now I want to know how I can convert this string:

XXXXXXXXXXXXXXXIXXX
X                 X
X XXXXXXXXXXXXXXXXX
X             X   X
X XXX XXXXX X X X X
X   X X   X X X X X
X X X XXX X X X X X
X X X     X X   X X
XXXXXXXXXXXOXXXXXXX

into a matrix like this:

data = [["X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "I", "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", "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", "X", "X", "X", "X", "X", "X", "X", "X", "X", "X", "O", "X", "X", "X", "X", "X", "X", "X"]]

What have you already tried (Post some code! Explain it!)? What happened (wrong result, error etc.)? — AncientSwordRage
– AncientSwordRage, Commented Mar 18, 2015 at 13:50
Is it necessary to convert types from str to list? Both are iterables and interchangeable in may cases. — myaut
– myaut, Commented Mar 18, 2015 at 13:50
My programm works. Its just this string that i dont know how to convert into a matrix. And i realy have no idea how could i do that for a string that has no fixed size — Sven
– Sven, Commented Mar 18, 2015 at 13:52
@Sven: Your labyrinth program uses a matrix that's a list of lists of strings, with each string being a single cell of the matrix. But myaut is saying that you can instead simply use a list of strings, with each string being a row of the matrix. And that will require only very minor changes to your code, and possibly no changes at all, depending on how you've written your code. — PM 2Ring
– PM 2Ring, Commented Mar 18, 2015 at 14:01
It's great that your labyrinth program works, but pureferret is asking you to post some code that attempts to convert the string into a matrix, since that's the topic of your question. Questions without relevant code risk getting closed. See stackoverflow.com/help/mcve — PM 2Ring
– PM 2Ring, Commented Mar 18, 2015 at 14:06

Igor · Accepted Answer · 2015-03-18 14:08:11Z

1

Worked for me:

[[x for x in line] for line in a.split('\n')]

Example:

>>> a = """
... XXXXXXXXXXXXXXXIXXX
... X                 X
... X XXXXXXXXXXXXXXXXX
... X             X   X
... X XXX XXXXX X X X X
... X   X X   X X X X X
... X X X XXX X X X X X
... X X X     X X   X X
... XXXXXXXXXXXOXXXXXXX
... """


>>> [[x for x in line] for line in a.split('\n')]
[[], ['X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'I', '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', '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', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'O', 'X', 'X', 'X', 'X', 'X', 'X', 'X'], []]

And to remove empty sublists:

[z for z in ([x for x in line] for line in a.split('\n')) if z]

answered Mar 18, 2015 at 14:08

Igor

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1 Comment

PM 2Ring Over a year ago

As jonrsharpe said in his comment on blue_note's answer, list(line) is better than [x for x in line].

blue note · Accepted Answer · 2015-03-18 13:59:42Z

1

assuming you string is defined as

text = '''
X....
'''

you get the matrix by

matrix = [[str(char) for char in line] for line in text.splitlines()]

answered Mar 18, 2015 at 13:59

blue note

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2 Comments

jonrsharpe Over a year ago

Why not just [list(line) for line in ...]? It's already a string, there's really no point explicitly "converting" each char to str.

blue note Over a year ago

@jonrsharpe: you' re right, I was just in "list comprehension" thinking mode

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