Hi there
I have a data file that looks something like this 
      Ob1    Ob1code   Ob2       Ob2code
HIT object1 563.43.78 object3 123.89.7777
HIT object1 563.43.78 object10 123.89.7777
HIT object1 563.43.78 object2 453.78.122
HIT object1 563.43.78 object5 457.8888.1
HIT object1 563.43.78 object4 123.89.7777
HIT object1 563.43.78 object6 566.2222.11
HIT object2 563.43.78 object3 123.89.7777
HIT object2 563.43.78 object7 456.222.1111
HIT object2 563.43.78 object8 990.7777.66
HIT object2 563.43.78 object5 457.8888.1
HIT object2 563.43.78 object13 123.89.7777
HIT object2 563.43.78 object9 1223.333.111

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What I would like to do is for objects 1 and 2
which of the 'Ob2codes' are common to both of them, and which 'Ob2codes' only occur with either one or the other 'Ob1's?
I have considered using two hashes, whereby the 'Ob2codes' common to both 'Ob1's' are stored and then any duplicate 'Ob2codes' are placed in a second hash for printing later, but haven't really gotten any further than that.
Any suggestions gratefully recieved.

In reply to How to check for duplicate entries by Angharad

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