## Regular Expression of starting with 0 and having multiple even 1’s or no 1

**Regular Expression =** **0 0*(10*10*)***

## DFA of strings starting with 0 and having multiple even 1’s or no 1

## Regular Expression of starting with 0 and having multiple consecutive 11’s or no 1 in the string. 0 must be only one time in the regular expression.

Let us see the Regular Expression of all those strings starting with 0 and having multiple even 1’s or no 1, having only one 0, defined over {0,1}

**Regular Expression = 0(11)***

## DFA of starting with 0 and having multiple even 1’s or no 1, having only one 0

## Rule

All those strings starting with 0 and having multiple even 1’s or no 1 must be accepted and all other strings must be rejected by our Regular Expression.

## Rejectable strings (not part of the language)

These strings are not part of the given language and must be rejected by our Regular Expression.

- 3 strings of length 1 = {1, no more string}
- 3 strings of length 2 = {11, 00, no more string}
- 3 strings of length 3= {001,000,100}
- 3 strings of length 4 = {0010, 0001, 0100}
- 3 strings of length 7 = {0111000, 0111110, 0011100}
- 3 strings of length 10 = {0000011111, 0011100001}
- 3 strings of length 15 = {000000000011111, 000001111100000, 000111111111000}
- 3 strings of length 20 = {00000000000111111111, 00000011111110000111, 00001111111000000000}
- 3 strings of length 25 = {0000000000000011111111111, 0000000000111111111111100, 0000000000111111111000111}
- Many other strings

__Acceptable strings (part of the language)__

These strings are part of the given language and must be accepted by our Regular Expression.

- 3 strings of length 1 = {0, no string}
- 3 strings of length 2 = {no string}
- 3 strings of length 3= {011, no more string}
- 3 strings of length 4 = {no string}
- 3 strings of length 7 = {0111111, no more string}
- 3 strings of length 10 = {no string}
- 3 strings of length 15 = {011111111111111, no more string}
- 3 strings of length 20= {no string}
- 3 strings of length 25= {0111111111111111111111111, no more string}
- Many other strings.

## Regular Expression of all those strings starting with a and having multiple even b’s or no b

Let us see the Regular Expression of all those strings starting with a and having multiple even b’s or no b defined over {a,b}

**Regular Expression = ****a(bb)***

## Rule

All those strings starting with a and having multiple even b’s or no b must be accepted and all other strings must be rejected by our Regular Expression.

## Rejectable strings (not part of the language)

These strings are not part of the given language and must be rejected by our Regular Expression.

- 3 strings of length 1 = {b, no more string}
- 3 strings of length 2 = {bb, aa, no more string}
- 3 strings of length 3= {aab,aaa,baa}
- 3 strings of length 4 = {aaba, aaab, abaa}
- 3 strings of length 7 = {abbbaaa, abbbbba, aabbbaa}
- 3 strings of length 10 = {aaaaabbbbb, aabbbaaaab}
- 3 strings of length 15 = {aaaaaaaaaabbbbb, aaaaabbbbbaaaaa, aaabbbbbbbbbaaa}
- 3 strings of length 20 = {aaaaaaaaaaabbbbbbbbb, aaaaaabbbbbbbaaaabbb, aaaabbbbbbbaaaaaaaaa}
- 3 strings of length 25 = {aaaaaaaaaaaaaabbbbbbbbbbb, aaaaaaaaaabbbbbbbbbbbbbaa, aaaaaaaaaabbbbbbbbbaaabbb}
- Many other strings

## Acceptable strings (part of the language)

These strings are part of the given language and must be accepted by our Regular Expression.

- 3 strings of length 1 = {a, no string}
- 3 strings of length 2 = {no string}
- 3 strings of length 3= {abb, no more string}
- 3 strings of length 4 = {no string}
- 3 strings of length 7 = {abbbbbb, no more string}
- 3 strings of length 10 = {no string}
- 3 strings of length 15 = {abbbbbbbbbbbbbb, no more string}
- 3 strings of length 20= {no string}
- 3 strings of length 25= {abbbbbbbbbbbbbbbbbbbbbbbb, no more string}
- Many other strings.

## Download RE Slides

Regular Expression of starting with 0 and having multiple even 1’s or no 1

## More Examples of Regular Expression

- Regular Expression for no 0 or many triples of 0’s and many 1 in the strings.
- RegExp for strings of one or many 11 or no 11.
- A regular expression for ending with abb
- A regular expression for all strings having 010 or 101.
- Regular expression for Even Length Strings defined over {a,b}
- Regular Expression for strings having at least one double 0 or double 1.
- Regular Expression of starting with 0 and having multiple even 1’s or no 1.
- Regular Expression for an odd number of 0’s or an odd number of 1’s in the strings.
- Regular Expression for having strings of multiple double 1’s or null.
- Regular Expression (RE) for starting with 0 and ending with 1.
- RE for ending with b and having zero or multiple sets of aa and bb.
- A regular expression of the second last symbol is 1.
- RE for starting with 1 having zero or multiple even 1’s.
- Regular Expression for multiple a’s and multiple b’s.
- RE for exactly single 1 many 0’s |exactly single a many b.
- A regular expression for strings starting with aa and ending with ba.
- A regular expression for the language of all consecutive even length a’s.
- A regular expression for the language of all odd-length strings
- A regular expression for the language of all even length strings but ends with aa.
- A regular expression for the language of an odd number of 1s.
- A regular expression for the language of even length strings starting with a and ending with b in theory of automata.
- A regular expression for the language of all even length strings but starts with a.
- A Regular Expression for the Language of all strings with an even number of 0’s or even number of 1’s.
- A regular expression for the language of all those strings end with abb.
- A regular expression for string having must 010 or 101.
- Regular expression of strings begin with 110

Regular expression of strings begin and end with 110

Regular expression of strings containing exactly three consecutive 1’s. - A Regular Expression of all strings divisible by 4.
- A Regular Expression Strings that does not contain substring 110.

## Tutorial: Regular Expression

A detailed tutorial of the regular expression is here in the link of regular expression tutorial. This page contains the practice questions of regular expressions with solutions.

**Tutorial covering the topics**

- Give a regular expression.
- Describe the strings of the regular expression.
- write a regular expression.
- create all strings from regular expression.
- Generate all strings from regular expression.
- Extract all strings from regular expression.
- Find all strings from regular expression.
- Examples of regular expression.

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