Regular Expressions 101

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"
(^[A-Za-z]{2}$)
"
1st Capturing Group
(^[A-Za-z]{2}$)
^ asserts position at start of the string
Match a single character present in the list below
[A-Za-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)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
$ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)
Your regular expression does not match the subject string.

Regular Expression
No Match

r"
"

Test String