正则表达式:^ 和 \A 之间的区别 [英] Regular Expressions: difference between ^ and \A

问题描述

^ 和 \A 之间的唯一区别是 \A 在换行后永远无法匹配吗?(即使在多行模式下)

Is the only difference between ^ and \A the fact that \A can never match after a line break? (even in multi-line mode)

The PCRE man page says:
^      assert start of string (or line, in multiline mode)
...
\A     matches at the start of the subject

谢谢！

推荐答案

是的.\A 将匹配您的值的最开头.^ 将匹配值的开头，但在多行模式(//m)下也会在换行符之后立即匹配.

Yes. \A will match at the very beginning of your value. ^ will match the beginning of the value, but will also match immediately after newlines in multiline mode (//m).

\Z 类似，但以值结尾.但是，它会也在值末尾的换行符之前匹配.如果您不想要这种行为，请使用 \z，它在值的末尾匹配 only.

The \Z is similar, but with the end of the value. However, it will also match before a newline at the end of the value. If you don't want this behaviour, use \z, which matches only at the end of the value.

有用的参考:perlre 手册页

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