Regular expressions

Regular Expression

Terminology

^_ - indicates a line that starts with _ .

_$ - indicates a string that ends with _ .

abc* - abc / |c|>=0

abc+ - abc / |c|>=1

abc? - abc / |c|={0,1}

abc{2} - abc / |c|=2

abc{2,5} - abc / 2<=|c|<=5

d - specifies the numbers one by one

(d)+ - indicates the numerical segment between two numbers

w - specifies letters one by one

(w)+ - indicates the letter segment between two letters, i.e. words

(D)+ - indicates the non-numeric portion between two numbers

s - space

[0-9] - specifies numbers in the range [0-9] one by one

[0-9]+ - specifies multiple numbers

[0-9]+ [a-z] +[0-9]+ -number, letter, number

[^_] – specifies everything except a space

[_] – marks only _s

• - specifies a single character

Example: (/d [a,z] + /d (,) /s [0,6]+) .$

Useful Links:
Regular expressions article/eng
Regular expressions article/rus
Regular expressions video tutorial/eng
Regular expressions video tutorial/rus