Lab 03

+

symbols of union of two languages

.

symbol of concatenation of languages

*

symbol of closure (or star, or Kleene Closure)

^

string should start with whatever symbols are after the symbol

$

string should end with whatever precedes the symbol

|

between strings en-closed by parentheses means either of the strings

[]

including ranges of characters, means any of the characters

+

means one or more occurrences of the expression preceding the symbol

*

after an expression means zero or more occurrences of the expression receding the symbol

?

the expression is optional

{n}

means n consecutive occurrences of the preceding expression

{n,}

means n or more consecutive occurrences of the preceding expression

{n, m}

means n to m occurrences of the preceding expression

.

means any character

a symbol used by regex must be escaped by preceding the character with a _

[^]

matches any character except those inside the square brackets