^ | It is used to match starting point of the line. |
$ | It is used to match terminating point of the line. |
. | It is used to match any one character excluding the newline. |
[…] | It is used to match any one character within the brackets. |
[^…] | It is used to match any one character which is not in the brackets. |
\\A | It is used to match starting point of the intact string. |
\\z | It is used to match terminating point of the intact string. |
\\Z | It is used to match end of the whole string excluding the new line, if it exists. |
re* | It is utilized to match zero or more appearances of the foregoing expressions. |
re+ | It is used to match one or more of the foregoing expressions. |
re? | It is used to match zero or one appearance of the foregoing expression. |
re{ n} | It is used to matches precisely n number of appearances of the foregoing expression. |
re{ n, } | It is used to match n or more appearances of the foregoing expression. |
re{ n, m} | It is used to match at least n and at most m appearances of the foregoing expression. |
q|r | It is utilized to match either q or r. |
(re) | It is utilized to group the Regular expressions and recollects the text that are matched. |
(?: re) | It also groups the regular expressions but does not recollects the matched text. |
(?> re) | It is utilized to match self-reliant pattern in absence of backtracking. |
\\w | It is used to match characters of the word. |
\\W | It is used to match characters of the non-word. |
\\s | It is utilized to match white spaces which are analogous to [\t\n\r\f]. |
\\S | It is used to match non-white spaces. |
\\d | It is used to match the digits i.e, [0-9]. |
\\D | It is used to match non-digits. |
\\G | It is used to match the point where the endmost match overs. |
\\n | It is used for back-reference to occupy group number n. |
\\b | It is used to match the word frontiers when it is out of the brackets and matches the backspace when it is in the brackets. |
\\B | It is used to match non-word frontiers. |
\\n, \\t, etc. | It is used to match the newlines, tabs, etc. |
\\Q | It is used to escape (quote) each of the characters till \\E. |
\\E | It is used in ends quoting starting with \\Q. |