Regular Expressions 101

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/
[a-zA-Z0-9_\.-]+@[a-zA-Z]+\.[A-Za-z]+(.[a-zA-Z]+)?
/
gm
Match a single character present in the list below
[a-zA-Z0-9_\.-]
+ matches the previous token between one and unlimited 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)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
_ matches the character _ with index 9510 (5F16 or 1378) literally (case sensitive)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
@ matches the character @ with index 6410 (4016 or 1008) literally (case sensitive)
Match a single character present in the list below
[a-zA-Z]
+ matches the previous token between one and unlimited 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)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
Match a single character present in the list below
[A-Za-z]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
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)
1st Capturing Group
(.[a-zA-Z]+)?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
. matches any character (except for line terminators)
Match a single character present in the list below
[a-zA-Z]
+ matches the previous token between one and unlimited 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)
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

Code Generator

Generated Code

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Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report.
For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php