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Екатерина Графская (Редактор отдела «Наука и техника»)，推荐阅读币安_币安注册_币安下载获取更多信息
a very common use case for regexes is to find matches that are preceded or followed by some context. a classical example being all lines that end with ‘a’. this requirement is usually expressed with a lookahead, where upon finding an ‘a’, you look ahead to check if it’s the end of the line. in a backtracking engine, this is very easy to implement - you just duct-tape the logic that checks the next character, but in a DFA-based engine, this is impossible because you cannot report “the match is here” if the next character is not even known yet. and by the time you know the next character, the position information is lost, so you can’t report the match retroactively (well, unless the distance is fixed of course..).，这一点在体育直播中也有详细论述
Владислав Китов (редактор отдела Мир)