Finding Four to Six letter words using regular expressions

In this regular expression we are going to find out All Four to Six letter words. A word is a unit (member) of language that represents a concept which can be expressively communicated with meaning. A word consists of one or more morphemes which are linked more or less tightly together, and has a phonetic value. Get more information about Finding Words using regular expressions.

Regular Expression Pattern

(?< =(?:\s|\G|\A))\w{4,6}(?=(?:\s|\Z|\.|\?|\!))

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In this regular expression we are going to find out All Words. A word is a unit (member) of language that represents a concept which can be expressively communicated with meaning. A word consists of one or more morphemes which are linked more or less tightly together, and has a phonetic value.

Regular Expression Pattern

^\b\w+\b$

A description of the regular expression:

First or last character in a word
Alphanumeric, one or more repetitions
First or last character in a word

How It Works

This regular expression will check First or last character in a word. An Alphanumeric, one or more repetitions and First or last character in a word.

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Finding Blank Lines using regular expressions

In this regular expression we are going to find out blank lines. Means we are going to search lines containing only spaces (or Whitespace) and end of line.

Regular Expression Pattern

^\s*$

A description of the regular expression:

Beginning of line or string
Whitespace, any number of repetitions
End of line or string

How It Works

This regular expression will check for blank lines contains only spaces (Whitespace). Here we are going to search Beginning of line followed by Whitespace, any number of repetitions and End of line or string.

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Validate an email address using regular expressions

email address are the means of communication with people around the world. While processing forms email address validation plays an important. Proper email validation strengthen our contact list, ban spamming and protect us from robot form filling (Form AutoFill).

Here we are going to design a regular expression pattern to validate email address. which will check to make sure an e-mail address is a valid address, and in proper format means containing an username, at sign (@), and valid hostname. For example, admin@samplehost.com is valid, but SPAM@badhost is invalid. Most of email service provides limit the use of literals for email address creation. Only letters (a-z,A-Z), numbers (0-9), hyphens (-), underscore (_) and periods (.) are allowed and no special characters are accepted. You can add or remove any literals to your regular expression.

Regular Expression Pattern

^([a-zA-Z0-9_\-\.]+)@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$
 
email with IP -
^([a-zA-Z0-9_\-\.]+)@(([a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3}))|(([01]?\d\d?|2[0-4]\d|25[0-5])\.){3}([01]?\d\d?|25[0-5]|2[0-4]\d))$

For more information on Regular Expressions IP Address Validation with .net

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Regular Expressions IP Address Validation with .net

An Internet Protocol (IP) address is a numerical identification (logical address) that is assigned to devices participating in a computer network utilizing the Internet Protocol for communication between its nodes.

IP Address Classes:

IP addresses are categories into five classes: Class A, Class B, Class C, Class D and Class E. Each class allows for a range of valid IP addresses. whereas classes A, B and C are used to communication.

Class A Internet Protocol (IP) address ranges include 1.0.0.0 to 126.255.255.255. This class supports 16 million hosts on each of the 127 networks. network 0.0.0.0 is reserved for use as the default route and the network 127.0.0.0 is reserved for the “loopback” function.

Class B Internet Protocol (IP) address ranges include 128.1.0.0 to 191.255.255.255. This class supports 65,000 hosts on each of the 16,000 networks.

Class D Internet Protocol (IP) address ranges include 224.0.0.0 to 239.255.255.255. This class is used to support multicasting.

Class E Internet Protocol (IP) address ranges include 240.0.0.0 to 254.255.255.254. This class is used for experimentation. Class E networks have never been documented or utilized in a standard way.

IP addresses are also commonly used to divide networks into smaller ones. This concept is called subnetting. Subnet addresses include 255.0.0.0 to 255.255.255.255

Dotted-Decimal Notation

To make Internet addresses easier for people to read and write, IP addresses are often expressed as four decimal numbers, each separated by a dot. This format is called “dotted-decimal notation.” Dotted-decimal notation divides the 32-bit Internet address into four 8- bit fields and specifies the value of each field independently as a decimal number with the fields separated by dots.

Regular Expression Pattern

^(([01]?\d\d?|2[0-4]\d|25[0-5])\.){3}([01]?\d\d?|25[0-5]|2[0-4]\d)$

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