Mapping method and device

A mapping method and device, which are applied to a primary server in a trunked system, wherein the trunked system further comprises various sub-servers. The method comprises: segmenting a received discrete set into several discrete sub-sets (S101); distributing each discrete sub-set to each corresponding sub-server, so that each sub-server respectively obtains, according to a pre-set offset calculation formula and a minimal perfect hash algorithm, an offset value corresponding to each discrete sub-set and a continuous integer sub-set, and then obtains a mapping continuous integer sub-set corresponding to each discrete sub-set by respectively summing each element value in the continuous integer sub-set and the offset value (S102); and acquiring each corresponding mapping continuous integer sub-set from each sub-server, and obtaining a mapping continuous integer set after combination (S103). The present method is not limited by a stand-alone memory and computing resources, thereby saving hardware resources, and can be used to perform corresponding linear expansion on an input discrete set, thereby improving the mapping conversion efficiency and the learning effect of a machine learning algorithm.