Depending on what easier means and what you actually want, the following trivial assignment will feed the entries from %a into %c and from %b into %c, replacing any duplicates from %a with the entry having the same key in %b. This seemed to fit your example data.
%c = ( %a, %b);

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Update: or from the shell (unsophisticated sorting though, else it lengthens a bit):
cat file1 file2 | perl -e 'while(<>){ /^((\d+\.){3}\d+)(.*)$/ and $c{ 
+$1 } = $1 . $2; } print values %c; ' | sort > file3;

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One world, one people

In reply to Re: Process and combine two CSV files into one by anonymized user 468275
in thread Process and combine two CSV files into one by DrAxeman

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