Tested for Python 2.7

If you have generated data for svmlight, but haven't changed your feature names to indices yet, let this script take care of it for you.

The SVM tool svmlight requires features to be represented by unique sorted indices, rather than by their names. This script takes a data file where features are still given strings and converts them into such indices. Optionally, the mapping from index to feature name can also be saved.

Input files must follow the regular svmlight format

<line> .=. <target> <feature>:<value> <feature>:<value> ... <feature>:<value> # <info>

with the exception that instead of

<feature> .=. <integer> | "qid"

you provide

<feature> .=. <string> | "qid"