million of lines still probably fit in memory.
Maybe. Or maybe not. But why take the chance? Especially with an AoA which has some extra cost. It is so easy to do everything in the first loop, when reading each line. And BTW, it is also probably faster, because using an array of arrays implies copying the data once more.

In reply to Re^2: Faster and more efficient way to read a file vertically -- updated by Laurent_R
in thread Faster and more efficient way to read a file vertically by Anonymous Monk

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