Editing Lempel–Ziv–Welch (section)

==Variants==
* LZMW (1985, by V. Miller, M. Wegman)<ref>David Salomon, ''Data Compression – The complete reference'', 4th ed., page 209.</ref> – Searches input for the longest string already in the dictionary (the "current" match); adds the concatenation of the previous match with the current match to the dictionary.  (Dictionary entries thus grow more rapidly; but this scheme is much more complicated to implement.)  Miller and Wegman also suggest deleting low-frequency entries from the dictionary when the dictionary fills up.
* LZAP (1988, by James Storer)<ref>David Salomon, ''Data Compression – The complete reference'', 4th ed., page 212.</ref> – modification of LZMW: instead of adding just the concatenation of the previous match with the current match to the dictionary, add the concatenations of the previous match with each initial substring of the current match ("AP" stands for "all prefixes").  For example, if the previous match is "wiki" and current match is "pedia", then the LZAP encoder adds 5 new sequences to the dictionary: "wikip", "wikipe", "wikiped", "wikipedi", and "wikipedia", where the LZMW encoder adds only the one sequence "wikipedia". This eliminates some of the complexity of LZMW, at the price of adding more dictionary entries.
* [[LZWL]] is a syllable-based variant of LZW.