Greediness of quantified subpatterns
What is the greediness of quantified subpatterns? What does it mean that a quantified subpattern is "greedy"?
How to show that a quantified subpattern is "greedy" on this PHP script: if ($t=10): echo "Just started...!"; endif; if ($t=11): echo "Hungry!"; endif; if ($t=12): echo ""Ah, lunch-time!"; endif;?
The greediness of quantified subpatterns is referring to the behavior on when to stop repeating a quantified subpattern in the matching process.
By default, a quantified subpattern is "greedy", that is, it will match as many times as possible (given a particular starting location) while still allowing the rest of the pattern to match.
For example: when applying pattern /a+a/ to "aaaa", the quantified subpattern /a+/ will, by default, match the first 3 characters "aaa" which still allowing the next subpattern /a/ to match the last character "a". In other words,
(a+)a # matches 'aaaa' with $1='aaa', not $1='a'
The regular expression to show the greediness of a quantified subpattern on the given PHP script:
(if .+ endif;) if - matches 'if' .+ endif; - matches as many characters as possible while 'end if;' is at the end
2013-01-26, 0👍, 0💬
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