I recently gathered, using a questionnaire, a set of opinions on the importance of various software components. Figuring that some form of Condorcet voting method would be the best way to obtain an overall rank, I opted to use OpenSTV to analyze it.

My data is in tabular format, space delimited, and looks more or less like:

A B C D E F G    # Candidates
5 2 4 3 7 6 1    # First ballot. G is ranked first, and E is ranked 7th
4 2 6 5 1 7 3    # Second ballot
etc

In this format, the number indicates the rank and the sequence order indicates the candidate. Each "candidate" has a rank (required) from 1 to 7, where a 1 means most important and a 7 means least important. No duplicates are allowed.

This format struck me as the most natural way to represent the output, being a direct representation of the ballot format.

The OpenSTV/BLT format uses a different method of representing the same info, conceptually as follows:

G B D C A F E    # Again, G is ranked first and E is ranked 7th
E B G A D C F    # 
etc

The actual numeric file format uses the (1-based) index of the candidate, rather than the label, and so is more like:

7 2 4 3 1 6 5    # Same ballots as before.
5 2 7 1 4 3 6    # A -> 1, G -> 7

In this format, the number indicates the candidate, and the sequence order indicates the rank. The actual, real, BLT format also includes a leading weight and a following zero to indicate the end of each ballot, which I don't care too much about for this.

My question is, what is the most elegant way to convert from the first format to the (numeric) second?