Hi all,

I have a big file with the following format:

<key>   <value>
6       9913
8       9913
10      9913
12      9913
14      9913
32      14456
35      9913
42      9913
44      24
46      24
50      24
[...]

[download]

The first column has sorted unique numbers and the second values associated with them. I need to look up this file using the first column as keys. For example, 32 -> 14456

I can't load the file in a hash (doesn't fit into memory), and reading one line at a time is too slow (even if I sort the numbers to search). Building an index seems useless too (the index wouldn't fit into memory and if I write in a file, the problem would be the same).

What would be the best way (defining best as the ratio between efficiency / simplicity of implementation) of doing this?

Is making a DB with the file or writing C subroutines to access the file the only way of improving this task?

Thanks in advance

citromatik

In reply to fast lookups in files by citromatik

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