study

study

study SCALAR

study

May take extra time to study SCALAR ($_ if unspecified) in anticipation of doing many pattern matches on the string before it is next modified. This may or may not save time, depending on the nature and number of patterns you are searching and the distribution of character frequencies in the string to be searched; you probably want to compare run times with and without it to see which is faster. Those loops that scan for many short constant strings (including the constant parts of more complex patterns) will benefit most.

Note that since Perl version 5.16 this function has been a no-op, but this might change in a future release.

(The way study works is this: a linked list of every character in the string to be searched is made, so we know, for example, where all