Regular expression

1. Example 1
Match text abcdefg
Match text abcde
Match text abc
Pattern is "abc"

2. Example 2
Match text abc123xyz
Match text define "123"
Match text var g=123;
Pattern is "123"

3. [abc] Only a, b, or c

4. [abc] Only a, b, or c

5. [^abc] Not a, b, nor c

6. Other format
[0-9] Number 0 to 9
{m} m repetitions
{m,n} m to n Repetitions
* Zero or more repetitions
+ One or more repetitions
. any Character

7. {m,n} m to n Repetitions

8. * Zero or more repetitions

9. + One or more repetitions

10. Other format
? Optional
s any Whitespace
^…$ Starts and ends
() capture Group
(a(bc)) capture Sub group
(a|b) Matchs a or b

11. ? Optional

12. s any Whitespace

13. ^…$ Starts and ends

14. () capture Group

15. (a(bc)) capture Sub group

16. (a|b) Matchs a or b

17. Other format
w any Alphanumeric character
W any Non-alphanumeric character
d any Digit
D any Non-digit character
s any Whitespace
S any Non-whitespace character