例如,可以使用正则表达式来匹配“2009年2月”吗？
沿线
\b(?:Jan(?:uary)?|Feb(?:ruary)?|...|Dec(?:ember)?) (?:19[7-9]\d|2\d{3})(?=\D|$)
那是
\b # a word boundary
(?: # non-capturing group
Jan(?:uary)? # Jan(uary)
|Feb(?:ruary)? #
|... # and so on
|Dec(?:ember)? # Dec(ember)
) # end group
# a space
(?: # non-capturing group
19[7-9]\d|2\d{3} # 1970-2999
) # end group
(?=\D|$) # followed by: anything but a digit or the end of string
