如何把txt文件变成arrays的hashmap

Question

I'm trying to take a text file with the format like this:

4
0 2 3 4
1 1 3 4
2 1 2 4
3 1 2 3

and parse it into something like this:

G = {1:[2,3,4], 2:[1,3,4], 3:[1,2,4], 4:[1,2,3]}

Where the first line is the number of lines and the first digit of every subsequent line is the order the array is in the hashmap.

Answer 1

data = """4
0 2 3 4
1 1 3 4
2 1 2 4
3 1 2 3""".splitlines()[1:]

# or
# with open("file.txt") as fp:
#     data = fp.readlines()[1:]

G = {i + 1: list(map(int, line.split()[1:])) for i, line in enumerate(data)}
print(G)

{1: [2, 3, 4], 2: [1, 3, 4], 3: [1, 2, 4], 4: [1, 2, 3]}

Answer 2

This is the general idea:

reader = open("INSERT FILE")
numLines = int(reader.readline().strip())
dict = {}

for line in reader:
    key = int(line[0])
    values = line[2:].split()
    values = [int(value) for value in values]
    dict[key+1] = values

print(dict)

Output:

{1: [2, 3, 4], 2: [1, 3, 4], 3: [1, 2, 4], 4: [1, 2, 3]}

Answer 3

One line solution, using dictionary comprehension:

{index:list(map(int, line.split(" ")[1:])) for index, line in enumerate(open(FILE_NAME).readlines()) if index != 0}

Edit: Explanation

• open(FILE_NAME).readlines() - Returns each line in the file as a string
• list(map(int, line.split(" ")[1:])) - Split each line by space, ignore the first element and convert the rest into int. Finally, you get a list of int.
• index != 0 to ignore the first line since it's of no use for us

Answer 4

I'm trying to take a text file with the format like this:

4
0 2 3 4
1 1 3 4
2 1 2 4
3 1 2 3

and parse it into something like this:

G = {1:[2,3,4], 2:[1,3,4], 3:[1,2,4], 4:[1,2,3]}

Where the first line is the number of lines and the first digit of every subsequent line is the order the array is in the hashmap.