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I have two csv files, there are some overlap columns between these two files. Assume one file is called as A.csv and another is called as B.csv. The intersection of A and B is called as C.

I would like to generate three new csv files: C; the subset of B after subtracting C from it, which is called as D; the union of A and D, which is called as E.

Are there any ways to do that in Linux/Unix using command without applying heavy weight programming languages?

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related question –  jw013 Sep 7 '12 at 20:03
Do some of the fields have quotes around them or embedded commas? If so, you need a “heavyweight” programming language. (Well, ok, you can get away with awk, but it's not pretty.) –  Gilles Sep 7 '12 at 22:11
No, they are just normal csv files. Every entry is either a word or a numerical value. –  user785099 Sep 8 '12 at 22:02
Could you add small sample input and resultant files?? –  Paddy3118 Sep 11 '12 at 12:48
I would have to see the file in question for a solution but do not underestimate the power of UNIX join and sort. –  terdon Nov 30 '12 at 12:52
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1 Answer

I would use python for this, don't be intimidated by python it's great at this kind of thing. My (rough and untested) solution for your problem would be:

f_csv_1 = open("csv1.csv")
f_csv_2 = open("csv2.csv")

csv_1 = f_csv_1.readlines()
csv_2 = f_csv_2.readlines()


intersection = list(set(csv_1) & set(csv_2))
union = list(set(csv_1) | set(csv_2))

out_1 = open("intersection.csv", "w")

for row in intersection:
      out_1.write("%s" % row)

out_2 = open("union.csv", "w")

for row in union:
      out_2.write("%s" % row)

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Remember about closing files. –  gorkypl Sep 9 '12 at 7:10
@gorkypl fixed­ –  trideceth12 Sep 9 '12 at 10:08
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