Question

I have a file with many lines each having over 20 numerical values, e.g.:

123 1 18 180776 4303656 1605 16468 0 51429 24230 0 0 0 4 8 0 8710 14705 1836 1 4 95
0 24538 0 187860 4264028 449 4711 0 2537 2537 0 0 5 0 0 0 6138 12880 1590 1 22 76
...

I’d like to:

1. read one line
2. save it in some python data type (what would be the best ?)
3. do some operations on each number taken from the above line, e.g.:
   • check if it is not above sth (and save the result)
   • check if it is not belowe sth (and save the result)
   • count its length (number of digits) (and save the result)
   • compare it to the previous number from the same column

   –

So after a one line (with numbers) I should have:

1. store each number
2. store additional attributes for each number

Each number is compared to previous one from the same column, store the result but then I can forget the previous line.

What data type would be the best to store above data ?

Answer 1

It’s hard to say which data type would be best without knowing what you’re gonna do with the aggregated information. However, a simple solution would be to use a list for each line, containing 2-tuples with the actual number and a dictionary with attributes:

line = [(1, {'even': False, 'foo': 'bar'}), ..., (2332, {'even': True, 'foo': 'baz'}), ...]

Here’s how to get this list starting from a line of text:

line = "4 0 2837 9323 ..."
line = [(int(n), dict()) for n in line.split()]

Then iterate the list and set attributes:

for n, attributes in line:
    ...
    attributes['foo'] = 'bar'