I am searching for a regex that would do the following:
- Check if the first character of the line is a - or :
- Check the succeeding characters of the line and it should be alphanumeric and whitespace are acceptable. There are maximum 10 characters per line.
- Should impose 5 max lines
I have been working on the following regex:
^[^:-][a-zA-Z0-9]{7}$ --> for nos. 1 & 2 condition. However, it seems like it is not working .
Then for the number of lines, I searched at https://www.oreilly.com/library/view/regular-expressions-cookbook/9781449327453/ch04s10.html . The regex below would check the number of lines.
^(?:[^\r\n]*(?:\r\n?|\n)){0,4}[^\r\n]*$
I don't know how to combine all the conditions I mentioned in a regex. It's my first time working on it.
Not Acceptable. There is - in 2nd line
Hello01
-Hello01
Hello0
Hello03
Hello04
Not Acceptable. More than 5 Lines
Hello01
-Hello01
Hello02
Hello03
Hello04
Hello05
Acceptable. No - or : in first character of the line
Hello01
Hello02
Hello03
Hello04
Hello05
CodePudding user response：
You can use
^[^\r\n:-][a-zA-Z0-9]{0,9}(?:\r?\n[^\r\n:-][a-zA-Z0-9]{0,9}){0,4}$
Details:
^- start of string[^\r\n:-]- any char that is not CR, LF,:and-[a-zA-Z0-9]{0,9}- zero to nine alnum chars(?:\r?\n[^\r\n:-][a-zA-Z0-9]{0,9}){0,4}- zero to four occurrences of\r?\n- CRLF or LF ending[^\r\n:-][a-zA-Z0-9]{0,9}- any char that is not CR, LF,:and-and then zero to nine alnum chars
$- end of string.