To see the syntax, usage and explanation of a particular symbol, you can click on it.
| ^(carret) | $(dollar) | .(dot) | \(backslash) | [](brackets) |
| -(hyphen) | [^(comb.) | |(pipe) | ?(question) | *(asterisk) |
| +(plus) | {n} | {n,m} | {n,} |
^(Carret)
Meaning: Matches the start of the string represented by the regular expression.
Usage/Example: ^ matches the a in abc
$(Dollar sign)
Meaning: Matches the end of the string represented by the regular expression.
Usage/Example: $ matches the c in abc
.(Dot)
Meaning: Matches any single character.
Usage/Example: . matches any single character x which is not a character with special meaning.
\(Backslash)
Meaning: Escapes the special meaning of special characters : ([\^$.|?*+()].
Usage/Example: When used before any special character it escapes the special meaning of that character and presents it as an ordinary character.
[](Square brackets)
Meaning: Starts and Closes a character class.
Usage/Example: [abc] matches a, b or c.
-(Hyphen)
Meaning: Specifies a range of characters.
Usage/Example: [a-zA-Z0-9] matches any letter of digit.
[^(Combination of [ and ^)
Meaning: When ^ is used immediatly after the opening [ , it negates the specified character class.
Usage/Example: [^a-c] matches any character except a, b or c.
|(Pipe symbol)
Meaning: Matches either one of the parts bordered with |.
Usage/Example: abc|def|xyz matches abc, def or xyz.
?(question mark)
Meaning: Makes the preceding term optional.
Usage/Example: abc? matches abc or ab.
*(Asterisk)
Meaning: Repeats the preceding term zero or more times.
Usage/Example: a* can match nothing or a+(a, aa, aaa, aaaa....)
+(Plus sign)
Meaning: Repeats the previous term once or more times.
Usage/Example: a+ matches a, aa, aaa, aaaa....
{n}(where n>=1)
Meaning: Repeats the previous term exactly n-times.
Usage/Example: a{3} matches aaa.
{n,m}(where n>=1; m>=n)
Meaning: Repeats the previous term between n and m times.
Usage/Example: a{3,5} matches aaa, aaaa or aaaaa.
{n,}(where n>=1)
Meaning: Repeats the previous term atleast n-times.
Usage/Example: a{2,} matches aa, aaa, aaaa, aaaaa....
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