Regular Expressions 101

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/
^((?:[1-9][0-9 ().-]{5,28}[0-9])|(?:(00|0)( ){0,1}[1-9][0-9 ().-]{3,26}[0-9])|(?:(\+)( ){0,1}[1-9][0-9 ().-]{4,27}[0-9]))$
/
gm
^ asserts position at start of a line
1st Capturing Group
((?:[1-9][0-9 ().-]{5,28}[0-9])|(?:(00|0)( ){0,1}[1-9][0-9 ().-]{3,26}[0-9])|(?:(\+)( ){0,1}[1-9][0-9 ().-]{4,27}[0-9]))
1st Alternative
(?:[1-9][0-9 ().-]{5,28}[0-9])
Non-capturing group
(?:[1-9][0-9 ().-]{5,28}[0-9])
Match a single character present in the list below
[1-9]
1-9 matches a single character in the range between 1 (index 49) and 9 (index 57) (case sensitive)
Match a single character present in the list below
[0-9 ().-]
{5,28} matches the previous token between 5 and 28 times, as many times as possible, giving back as needed (greedy)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
().-
matches a single character in the list ().- (case sensitive)
Match a single character present in the list below
[0-9]
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
2nd Alternative
(?:(00|0)( ){0,1}[1-9][0-9 ().-]{3,26}[0-9])
Non-capturing group
(?:(00|0)( ){0,1}[1-9][0-9 ().-]{3,26}[0-9])
2nd Capturing Group
(00|0)
1st Alternative
00
00
matches the characters 00 literally (case sensitive)
2nd Alternative
0
0 matches the character 0 with index 4810 (3016 or 608) literally (case sensitive)
3rd Capturing Group
( ){0,1}
{0,1} matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
matches the character with index 3210 (2016 or 408) literally (case sensitive)
Match a single character present in the list below
[1-9]
1-9 matches a single character in the range between 1 (index 49) and 9 (index 57) (case sensitive)
Match a single character present in the list below
[0-9 ().-]
{3,26} matches the previous token between 3 and 26 times, as many times as possible, giving back as needed (greedy)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
().-
matches a single character in the list ().- (case sensitive)
Match a single character present in the list below
[0-9]
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
3rd Alternative
(?:(\+)( ){0,1}[1-9][0-9 ().-]{4,27}[0-9])
Non-capturing group
(?:(\+)( ){0,1}[1-9][0-9 ().-]{4,27}[0-9])
4th Capturing Group
(\+)
\+ matches the character + with index 4310 (2B16 or 538) literally (case sensitive)
5th Capturing Group
( ){0,1}
{0,1} matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
matches the character with index 3210 (2016 or 408) literally (case sensitive)
Match a single character present in the list below
[1-9]
1-9 matches a single character in the range between 1 (index 49) and 9 (index 57) (case sensitive)
Match a single character present in the list below
[0-9 ().-]
{4,27} matches the previous token between 4 and 27 times, as many times as possible, giving back as needed (greedy)
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
().-
matches a single character in the list ().- (case sensitive)
Match a single character present in the list below
[0-9]
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String