3 d•ã@s*dZdd„Zdd„Zdd„Zddd „Zd S)z# Tools for comparing ranked lists. ccsRt|ƒ}t|ƒ}x<|D]4}y|||||fVWqtk rHYqXqWdS)z¸Finds the difference between the values in ranks1 and ranks2 for keys present in both dicts. If the arguments are not dicts, they are converted from (key, rank) sequences. N)ÚdictÚKeyError)Úranks1Úranks2Úk©rú5/tmp/pip-build-v9q4h5k9/nltk/nltk/metrics/spearman.pyÚ_rank_dists s rcCsjd}d}x*t||ƒD]\}}|||7}|d7}qWydd||||dStk rddSXdS)aUReturns the Spearman correlation coefficient for two rankings, which should be dicts or sequences of (key, rank). The coefficient ranges from -1.0 (ranks are opposite) to 1.0 (ranks are identical), and is only calculated for keys in both rankings (for meaningful results, remove keys present in only one list before ranking).ééégN)rÚZeroDivisionError)rrÚnÚresrÚdrrrÚspearman_correlationsrcCsdd„t|ƒDƒS)z„Given a sequence, yields each element with an increasing rank, suitable for use as an argument to ``spearman_correlation``. css|]\}}||fVqdS)Nr)Ú.0Úirrrrú 1sz&ranks_from_sequence..)Ú enumerate)ÚseqrrrÚranks_from_sequence-srçVçž¯Ò s