[epistasis]

>I have seen people parsing Gigabytes-files with one line of Awk

I feel exactly the opposite. I'm suspicious of anyone that does not use AWK (or other Unix text utilities) as a standard tool for checking the integrity of multi-gigabyte files, or generating summaries. AWK is super-fast, allows highly flexible checks, and allows quick and reliable interaction with huge amounts of data in the way that a script can not.

[mjcohenw]

I love awk. I once had to search a multi-megabyte hunk of data that was made up of 25-bit data items packed into 32-bit words. Instead of doing bit packing and unpacking, I converted the words into 32 character strings of 1's and 0's. I ended up with a string 300,000,000 (that's three hundred million) characters long!!! Awk had no problems handling it.

To build the string, I had to concatenate 1024 of the 32 characters strings to an intermediate string, and then concatenate these into the final monster, because concatenate just the 32 character strings took too long - a reallocation after every concatenation.

That was fun.

[dalke]

I believe this is an example of the sort of thing that the essay author complained about.

Bit-packing is simple. You spent a lot of time working around problems that shouldn't have existed in the first place. Even when using the approach you described, here is Python code which does what you described:

    >>> byte_to_bits = dict((chr(i), bin(i)[2:].zfill(8)) for i in range(256))
    >>> byte_to_bits["A"]
    '01000001'
    >>> as_bits = "".join(byte_to_bits[c] for c in open("benzotriazole.sdf").read())
    >>> as_bits[:16]
    '0000110100001010'
    >>> chr(int(as_bits[:8], 2))
    '\r'
    >>> chr(int(as_bits[8:16], 2))
    '\n'
    >>> open("benzotriazole.sdf").read(2)
    '\r\n'

This keeps everything in memory, since 300MB is not a lot of memory. If it was in the GB range then I would have written to a file instead of building an in-memory string.

The run-time was small enough that I didn't notice it.

The thing is, you succeeded in solving the problem, and are justly proud of your success. This is how a lot of scientists feel. But a lot of CS people look at the wasted work when there are simpler, better, more maintainable ways.

[east2west]

I wasn't appalled by AWK language but the blind switching of two lines which were assumed to be paired reads when many reads are not paired. It is precisely lack of checking that is a problem. I have nothing against AWK, although personally I use Python for massaging data.