• Posts
  • RSS
  • ◂◂RSS
  • Contact

  • Sorting mixed lists of numbers and strings

    June 26th, 2009
    programming, tech
    Imagine you have this list:
    fname_0006.v0_word 2
    fname_0007.v0_word 12
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 8
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0005.v0_word 24
    
    Imagine further that you want to sort it. Unfortunately, I can't get gnu sort to let me specify which fields are numeric and which now. That is, I can do:
    $ cat file.txt | sort
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 24
    fname_0005.v0_word 8
    fname_0006.v0_word 2
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0007.v0_word 12
    
    Or I can do:
    $ cat file.txt | sort -n
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 24
    fname_0005.v0_word 8
    fname_0006.v0_word 2
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0007.v0_word 12
    
    Or I can do:
    $ cat file.txt | sort -n -k1,1 -k2,2
    fname_0006.v0_word 2
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 8
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0007.v0_word 12
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0005.v0_word 24
    
    You might think this would work:
    $ cat file.txt | sort -k1,1 -kn2,2
    fname_0006.v0_word 2
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 8
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0007.v0_word 12
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0005.v0_word 24
    
    But nothing seems to make it do the right thing. So I abandoned sort for python:
    $ cat simple_sorter.py
    import fileinput
    
    def tidy(x):
        try:
            return int(x)
        except ValueError:
            return x
    
    line_bits = []
    
    for line in fileinput.input():
        line_bits.append([tidy(field) for field in line.split()])
    
    for bits in sorted(line_bits):
        print " ".join(str(bit) for bit in bits)
    
    $ cat tmp.txt | python simple_sorter.py
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 8
    fname_0005.v0_word 24
    fname_0006.v0_word 2
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0007.v0_word 12
    

    Update 2013-08-22: Thinking now, if I had to do it on the terminal I would do:

    $ cat file | awk '{print $1, $2+1000}' | sort | awk '{print $1, $2-1000}'
    fname_0001.v0_word 15
    fname_0002.v0_word 23
    fname_0003.v0_word 5
    fname_0003.v0_word 7
    fname_0005.v0_word 8
    fname_0005.v0_word 24
    fname_0006.v0_word 2
    fname_0006.v0_word 9
    fname_0007.v0_word 11
    fname_0007.v0_word 12
    
    Adding 1000 (or any number with more digits than your biggest number) puts in leading digits, fixing sorting. It's basically decorate-sort-undecorate.

    Comment via: facebook

    Recent posts on blogs I like:

    How did we decide to have a kid?

    ...and then some more kids? The post How did we decide to have a kid? appeared first on Otherwise.

    via Otherwise January 28, 2023

    My Rainbow Kit

    For Christmas I got a really fun kit about rainbows. It had a rainbow catcher, a really cool necklace, a streamer thingy, and it also had a really really cool pinwheel, and it also had a bracelet and a pinata. Unfortunately the pinata didn't work out …

    via Anna Wise's Blog Posts January 5, 2023

    Phones

    I think that once a kid is in third grade they should be able to get a phone. I think that while sometimes parents might want kids not to have them at certain ages, phones can be quite useful at times. Tablets don't have GPS, they don't have WiFi…

    via Lily Wise's Blog Posts January 5, 2023

    more     (via openring)


  • Posts
  • RSS
  • ◂◂RSS
  • Contact