patterns symbol in regular expression

Question

I am new to regex,

Can anyone explain for me the patterns:

(<form[^\a]*</form>|<FORM[^\a]*</FORM>)
(method="[a-zA-Z]*|METHOD="[a-zA-Z]*)

RegEx Explainer link: http://regexper.com/#(%3Cform%5B%5E%5Ca%5D*%3C%5C%2Fform%3E%7C%3CFORM%5B%5E%5Ca%5D*%3C%5C%2FFORM%3E)(method%3D%22%5Ba-zA-Z%5D*%7CMETHOD%3D%22%5Ba-zA-Z%5D*)%0A — Byte Commander, Nov 20 '15 at 14:17

score 1 · Answer 1 · answered Nov 20 '15 at 16:45

1

Two great resources for RegExp: Debugexx and regular expressions ₁₀₁

(<form[^\a]*</form>|<FORM[^\a]*</FORM>)

Regular expression visualization

_Debuggex

_{regular expressions ₁₀₁}

(method="[a-zA-Z]*|METHOD="[a-zA-Z]*)

Regular expression visualization

_Debuggex

_{regular expressions ₁₀₁}

answered Nov 20 '15 at 16:45

A.B.

90,397

score 0 · Accepted Answer · answered Nov 20 '15 at 14:24

From https://myregextester.com/index.php# (enter pattern in the field Match pattern and make sure you have ticked Explain. then click Submit):

----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    <form                    '<form'
----------------------------------------------------------------------
    [^\a]*                   any character except: '\a' (alarm) (0 or
                             more times (matching the most amount
                             possible))
----------------------------------------------------------------------
    </form>                  '</form>'
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    <FORM                    '<FORM'
----------------------------------------------------------------------
    [^\a]*                   any character except: '\a' (alarm) (0 or
                             more times (matching the most amount
                             possible))
----------------------------------------------------------------------
    </FORM>                  '</FORM>'
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
                           '\r\n'
----------------------------------------------------------------------
  (                        group and capture to \2:
----------------------------------------------------------------------
    method="                 'method="'
----------------------------------------------------------------------
    [a-zA-Z]*                any character of: 'a' to 'z', 'A' to 'Z'
                             (0 or more times (matching the most
                             amount possible))
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    METHOD="                 'METHOD="'
----------------------------------------------------------------------
    [a-zA-Z]*                any character of: 'a' to 'z', 'A' to 'Z'
                             (0 or more times (matching the most
                             amount possible))
----------------------------------------------------------------------
  )                        end of \2
----------------------------------------------------------------------
                           '\r\n'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

any character except: '\a' (alarm) (except a how ?? how can be (a) letter in form) ? — Vendetta, Nov 20 '15 at 14:25
i mean
something like that there's a in "name" ?? it means except this a ?? — Vendetta, Nov 20 '15 at 14:28
The pattern [^\a]* gets evaluated and means that it matches a character different from the special character \a which is usually not printable but some kind of control character. Therefore that does not make much sense to me either. And the * means that this part may appear 0 times, once or any other number. — Byte Commander, Nov 20 '15 at 14:31

patterns symbol in regular expression

2 Answers2