I have the following regular expressions that extract everything after first two alphabets
^[A-Za-z]{2})(\w )($) $2
now I want to the extract nothing if the data doesn't start with alphabets.
Example:
AA123 -> 123
123 -> ""
Can this be accomplished by regex?
CodePudding user response：
Introduce an alternative to match any one or more chars from start to end of string if your regex does not match:
^(?:([A-Za-z]{2})(\w )|. )$
See the regex demo. Details:
^- start of string(?:- start of a container non-capturing group:([A-Za-z]{2})(\w )- Group 1: two ASCII letters, Group 2: one or more word chars|- or.- one or more chars other than line break chars, as many as possible (use[\w\W]to match any chars including line break chars)
)- end of a container non-capturing group$- end of string.
CodePudding user response：
Your pattern already captures 1 or more word characters after matching 2 uppercase chars. The $ does not have to be in a group, and this $2 should not be in the pattern.
^[A-Za-z]{2})(\w )$
See a regex demo.
Another option could be a pattern with a conditional, capturing data in group 2 only if group 1 exist.
^([A-Z]{2})?(?(1)(\w )|. )$
^Start of string([A-Z]{2})?Capture 2 uppercase chars in optional group 1(?Conditional(1)(\w )If we have group 1, capture 1 word chars in group 2|Or.Match the whole line with at least 1 char to not match an empty string
)Close conditional$End of string
For a match only, you could use other variations Using \K like ^[A-Za-z]{2}\K\w $ or with a lookbehind assertion (?<=^[A-Za-z]{2})\w $