Regular Expressions 101

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"
\b[A-Z]{2}[a-zA-Z0-9]{6}\b
"
g
\b assert position at a word boundary: (^\w|\w$|\W\w|\w\W)
Match a single character present in the list below
[A-Z]
{2} matches the previous token exactly 2 times
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
Match a single character present in the list below
[a-zA-Z0-9]
{6} matches the previous token exactly 6 times
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
\b assert position at a word boundary: (^\w|\w$|\W\w|\w\W)
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.

Regular Expression
No Match

r"
"
g

Test String