noa*_*oah 4 regex perl greedy quantifiers regex-greedy
如果我有一个未知的结构字符串:
"stuff I don't care about THING different stuff I don't care about THING ... THING even more stuff I don't care about THING stuff I care about"
我想捕捉"我关心的东西",它总是在最后一次出现之后.有可能出现0次或多次.如果有0次出现则没有我关心的东西.字符串不能以THING开头或结尾.
一些可能的字符串
"stuff I don't care about THING stuff I care about"
"stuff I don't care about"
一些不可能的字符串:
"THING stuff I care about"
"stuff I don't care about THING stuff I don't care about THING"
我目前解决这个问题的方法是使用带有两个贪心量词的正则表达式,如下所示:
if( /.*THING(.*)/ ) {
$myStuff = $1;
}
它似乎有效,但我的问题是两个贪婪量词如何相互作用.第一个(最左边)贪婪量词总是"比第二个更贪婪"吗？
基本上我保证不会得到如下分割:
"stuff I don't care about THING"
$1 = "different stuff I don't care about THING even more stuff I don't care about THING stuff I care about"
与我想要的分裂相比:
"stuff I don't care about THING different stuff I don't care about THING even more stuff I don't care about THING"
"stuff I care about"
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