Regular Expressions 101

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/
^[0-9a-zA-Z-_\$#]+@[0-9a-zA-Z-_\$#]+\.[a-zA-Z]{2,5}
/
^ asserts position at start of the string
Match a single character present in the list below
[0-9a-zA-Z-_\$#]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
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)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
_ matches the character _ with index 9510 (5F16 or 1378) literally (case sensitive)
\$ matches the character $ with index 3610 (2416 or 448) literally (case sensitive)
# matches the character # with index 3510 (2316 or 438) literally (case sensitive)
@ matches the character @ with index 6410 (4016 or 1008) literally (case sensitive)
Match a single character present in the list below
[0-9a-zA-Z-_\$#]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
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)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
_ matches the character _ with index 9510 (5F16 or 1378) literally (case sensitive)
\$ matches the character $ with index 3610 (2416 or 448) literally (case sensitive)
# matches the character # with index 3510 (2316 or 438) literally (case sensitive)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
Match a single character present in the list below
[a-zA-Z]
{2,5} matches the previous token between 2 and 5 times, as many times as possible, giving back as needed (greedy)
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)
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/

Test String