This is a partial that considers regex items useful in the matching of telephone numbers.
String Position
Enclose a pattern with these to ensure matching to the full number.
Syntax
Description
^
Start of String: A ^ matches the start of the string.
$
End of String: A $ matches the end of the string.
Character Types
Syntax
Description
.
Any Character:
Match any character.
\d
Any Digit:
Match any digit. This just matches 0 to 9, not the dialing characters *, + and #.
\
Escape:
Use \ to escape characters that otherwise are regex commands. For example, \* matches a * digit, \+ matches a +.
Note: You do not need the escape character when the character to match is in [] brackets.
Group
Syntax
Description
|
Or:
Separate alternate possible matches. For example: 569|669 matches either 569 or 669. You can specify multiple alternates, for example: 569|669|779.
( )
Group:
Use ( ) brackets to group syntax. When performing digit translations, the element $1 in a translation represents the digits matched by the syntax in the first pair of ( ) brackets in the original pattern, $2 the second pair of brackets, and so on.
[ ]
Range of Characters:
Use [ ] square brackets to group specific characters or a character range to match. For example: [569] matches a 5, 6 or 9; [5-7] matches a 5, 6 or 7; [0-9*#+] matches any telephone number character.
When used in [ ] brackets, characters such as + and * do not need a preceding \ escape.
Use a ^ character inside the [] brackets to perform a non-match. For example: [^569] matches any digit other than a 5, 6 or 9.
Number of Matches
Syntax
Description
?
Match zero or one:
Use a ? question mark to match zero or one occurrences of the preceding element. For example: ^\+? matches numbers beginning with or without a + prefix.
*
Match zero or more:
Use an * to match zero or more occurrences of the preceding element. For example: ^1.*$ matches 1 and numbers beginning with a 1. To match an actual *, use \*.
+
Match one or more:
Use a + plus sign to match one or more occurrences of the preceding element. For example: ^1.+$ matches number beginning with a 1 but not just 1. To match an actual +, use \+.
{n}
Match N times:
Match the preceding item exactly n times. For example: ^.{3} matches 3-digit numbers.
{n,}
Match N or more times:
Match the preceding item n or more times. For example: ^. {3,}$ matches 3-digit or longer numbers.
{,m}
Match up to M times:
Match the preceding item up to m times. For example: ^.{,4}$ matches numbers up to 4-digits long.
{n,m}
Match between N to M times:
Match the preceding item at least m times, but no more than n times. For example: ^.{3,4}$ matches 3 and 4-digit numbers.
