打开文件并创建2D数组

Question

I have the file mapData.txt , which contains several arrays:

[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1]
[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]

How would I open this file, and create a 2D array using these lines? For example, after creating the 2D array (called, say, " worldMap "), if I were to type:

print(worldMap[0][0])

It would print 1

Answer 1

You should add error handling code but this seems to work at least with your example:

import json

worldMap = []
with open('mapData.txt', 'r') as datafile:
    for line in datafile:
        worldMap.append(json.loads(line))
    print(worldMap[0][0])

Answer 2

As a straightforward, and so efficient approach, you can just use numpy.genfromtxt :

import numpy as np

a = np.genfromtxt('a.txt', delimiter=',')

Answer 3

You can use ast.literal_eval to evaluate each line in your file, or parse it yourself as follows:

>>> def parse_line(line):
...     return line.strip('\n[]').split(',')
...
>>> with open('myfile.txt') as f:
...     world_map = [list(map(int,parse_line(line))) for line in f]
...
>>> pprint(world_map)
[[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
 [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]
>>>

But you should really consider using an existing text-serialization format, like json . So, for example:

>>> my_list = [[1, 2, 3], [4, 5, 6]]
>>> import json
>>> with open('my_list.json', 'w') as f:
...     json.dump(my_list, json)
...

So the above writes the json file to disk. Now, to load from disk:

>>> with open('my_list.json') as f:
...     list2 = json.load(f)
...
>>> list2
[[1, 2, 3], [4, 5, 6]]
>>>