
Show HN: Basic Set Operations - alephnullco
https://sets.alephnull.co
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CarolineW
I can see how some people would want a web-based tool to used quickly and
easily, although personally it's not the approach I would take. Many years ago
I wrote python programs set_minus, set_union, and set_intersect that take two
(or more) sets and print the appropriate result. For example

    
    
        set_minus A B
    

... prints every line in A that's not in B. Similarly the others.

Fast, clean, command-line, results to be piped to be processed or put into
files.

Alternatively, if you want to union files you can just do this:

    
    
        sort A B | sort -u
    

If you want to find the intersection:

    
    
        sort <( sort -u A ) <( sort -u B ) \
        | uniq -c \
        | grep " 2 " \
        | sed "s/^ *2 *//"
    

So all these things are easily done from the command line.

Even so, as I said, I can see how some people would want a web-based tool, so
thanks for sharing!

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alephnullco
Hey guys!

I thought this might be interesting to other people! I built this little tool
because I often found myself needing to quickly calculate a union,
intersection, or difference of two lists, but there wasn't an easy way to it
(aside from pulling up Excel and building a v-lookup).

I thought it might be useful to share, I've been using it a bunch to just
quickly do some data operations and then drop the result into a SQL query or
job processor.

Let me know if you have any feedback!

