如何使用python从文件中读取数据到数组中？

Question

I need to somehow read data into array to preform calculations with each number.

I have .txt file in following format.

4
1 2 3 4
2 4 6 8
3 6 9 12
4 8 12 16

The structure depends on number in the first line, here it is 4 . Meaning that it is 4x4 matrix.

Now, I believe that to preform calculations calculations with each number it would be easiest to store matrix into two-dimensional array. In that way each element would be accessible through array indices like this:

data[i][j]

Where data[4][3] = 16

How to fetch data into such array ? I'm in trouble here.

I tried following

def get_data(file):

with open(file) as f:
    N = f.readline()
data = [line.strip('\n') for line in open(file)]

but it saves each line to the place of index. So I have data[1] = ['1 2 3 4'] using this method.

Note that each number is separated by space and there is newline character \\n at the end of each line.

Answer 1

You're close. You just need to go a step further and split each line you read in, into a separate list. Additionally, you also need to convert your data into integers:

def get_data(file):
    with open(file) as f:
        data = [line.split() for line in list(f)]
        return [[int(el) for el in line] for line in data]

Answer 2

you can open file in read mode with:

file = open("new_text", "r")

then, read each line in file as:

for each_line in file:
    print(each_line)

to make a matrix you can write as:

matrix = []

for each_line in file:
    matrix.append(each_line.split()) #each_line.split will make a array and then we append this in matrix

print(matrix)

Note, here as first element of the matrix we have 4 which is read from the file to remove the element we can use pop() method .