Reading data from a text file and populate a list using a 1-liner

Question

For solving Project Euler's problem#67 , i used below code to read data & load data in the initial list, D.

I am wondering if all these can be done in Pythonic 1-liner

f=open("triangle.txt")
A=[]
for i in range(100):
    A.append((f.readline()).strip())

// init 
D=[]
for i in range(100):
    D.append((A[i]).split())
for i in range(100):
        for j in range(len(D[i])):
            D[i][j]= int(D[i][j])

Whereas, the data format is like this:

59
73 41
52 40 09
26 53 06 34
10 51 87 86 81
61 95 66 57 25 68
...................
.....................

Answer 1

Yes, by using a list comprehension (Python 2 or 3):

with open('triangle.txt') as infh:
    D = [[int(w) for w in line.split()] for line in infh]

or, if using Python 2, using map() :

with open('triangle.txt') as infh:
    D = [map(int, line.split()) for line in infh]

map() in Python 3 returns an iterator; in Python 2 it returns a list and would be faster for this usecase.