Regular Expressions 101

Explanation
Pro

Group with flags gm(?m:(?:,|^)"|(?!^)\G)

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

1st Alternative(?:,|^)"

Non-Capturing Group(?:,|^)

1st Alternative,

,the literal , (44₁₀ / 54₈ / 2C₁₆)

2nd Alternative^

^start of line

"the literal " (34₁₀ / 42₈ / 22₁₆)

2nd Alternative(?!^)\G

Negative Lookahead(?!^)

^start of line

\Gstart of current search

Negated Character Class[^",]*

*matches any number of characters outside the set below:

"the literal " (34₁₀ / 42₈ / 22₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match

,the literal , (44₁₀ / 54₈ / 2C₁₆)

Positive Lookahead(?=[^"]*")

Negated Character Class[^"]*

*matches any number of characters outside the set below:

"the literal " (34₁₀ / 42₈ / 22₁₆)

Global pattern flags

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

Detailed match information will be displayed here automatically.

25 tokens

(?m:(?:,|^)"|(?!^)\G)[^",]*\K,(?=[^"]*")

New

NA19900,4,111629038,0;0,0;0,"GSA-rs16997168,rs16997168,rs2w34r23424",C,T,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0

NA19900,4,111629038,0;0,0;0,"GSA-rs16997168,rs16997168,rs2w34r23424",C,T,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0