问题
I'm trying to match the beginning of a file in a VSCode regex search to find and remove the following pattern:
//
Anything else to leave in place
etc.
I'd like to remove the first line in all files that contain //\n as the first characters. However when I perform a regex search for //\n it matches all occurences in all files obviously, regardless of their position in the file.
The regex language mentions the existence of \A to match the beginning of a line, or file in some editors, but VSCode rejects this regex as invalid: \A//\n.
So my question is, how can I match the beginning of a file in VSCode to achieve what I need?
回答1:
The beginning of a file in Visual Studio Code regex can be matched with
^(?<![.\n])
^(?<![\w\W])
^(?<![\s\S\r])
You may use
Find What: ^//\n([\s\S\r]*)
Replace With: $1
Or, since nowadays VSCode supports lookbehinds as modern JS ECMAScript 2018+ compatible environments, you may also use
Find What: ^(?<![\s\S\r])//\n
Replace With: empty
If you wonder why [\s\S\r] is used and not [\s\S], please refer to Multi-line regular expressions in Visual Studio Code.
Details
^- start of a line//- a//substring\n- a line break([\s\S\r]*)- Group 1 ($1): any 0 or more chars as many as possible up to the file end.
The ^(?<![\s\S\r])//\n regex means:
^(?<![\s\S\r])- match the start of the first line only as^matches start of a line and(?<![\s\S\r])negative lookbehind fails the match if there is any 1 char immediately to the left of the current location//\n-//and a line break.
来源：https://stackoverflow.com/questions/60090875/match-the-beginning-of-a-file-in-a-vscode-regex-search