Regular Expressions 101

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/
^(1|B)[A-Z0-9]{6}\.1L[1-9]{1}$
/
gm
^ asserts position at start of a line
1st Capturing Group
(1|B)
1st Alternative
1
1 matches the character 1 with index 4910 (3116 or 618) literally (case sensitive)
2nd Alternative
B
B matches the character B with index 6610 (4216 or 1028) literally (case sensitive)
Match a single character present in the list below
[A-Z0-9]
{6} matches the previous token exactly 6 times
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)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
1L
matches the characters 1L literally (case sensitive)
Match a single character present in the list below
[1-9]
{1} matches the previous token exactly one time (meaningless quantifier)
1-9 matches a single character in the range between 1 (index 49) and 9 (index 57) (case sensitive)
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String

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