Regular Expressions 101

\na line-feed (newline) character (ASCII 10)

Negative Lookahead(?!\d+,)

\d+a digit, repeated at least once

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

\n(?!\d+,)

New

id, text field1, text field2
1,some text,another text
2,some 
1999-06-21 text,another text
3,some text,another text
1a,wewe