You are viewing the version of this documentation from Perl blead. This is the main development branch of Perl. (git commit 63b30a217f0590c255f9ccdb893dc2fa51bc68b0)
study SCALAR
study

At this time, study does nothing. This may change in the future.

Prior to Perl version 5.16, it would create an inverted index of all characters that occurred in the given SCALAR (or $_ if unspecified). When matching a pattern, the rarest character from the pattern would be looked up in this index. Rarity was based on some static frequency tables constructed from some C programs and English text.