Regular Expressions 101

Pro

^start of line

chrthe literal text chr (case insensitive)

Non-Capturing Group(?:0?[1-9]|[1-9][0-9]|[MXY])

1st Alternative0?[1-9]

0?optionally matches the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

2nd Alternative[1-9][0-9]

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

3rd Alternative[MXY]

Character Class[MXY]

Mthe literal M (77₁₀ / 115₈ / 4D₁₆) (case insensitive)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case insensitive)

Ythe literal Y (89₁₀ / 131₈ / 59₁₆) (case insensitive)

\ta tab character (ASCII 9)

0*the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated any number of times

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

Character Class[0-9]*

*matches any number of characters from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\ta tab character (ASCII 9)

Negated Character Class[^\t]*

*matches any number of characters outside the set below:

\ta tab character (ASCII 9)

Non-Capturing Group(?:\t[ATCG]){2}

{2}repeats the group contents below exactly 2 times:

\ta tab character (ASCII 9)

Character Class[ATCG]

Athe literal A (65₁₀ / 101₈ / 41₁₆) (case insensitive)

Tthe literal T (84₁₀ / 124₈ / 54₁₆) (case insensitive)

Cthe literal C (67₁₀ / 103₈ / 43₁₆) (case insensitive)

Gthe literal G (71₁₀ / 107₈ / 47₁₆) (case insensitive)

\ta tab character (ASCII 9)

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

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

No unit tests · Add a test to get started

25 tokens

^chr(?:0?[1-9]|[1-9][0-9]|[MXY])\t0*[1-9][0-9]*\t[^\t]*(?:\t[ATCG]){2}\t

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