# Regular Expressions 101

## Flavor

• PCRE2 (PHP >=7.3)
• PCRE (PHP <7.3)
• ECMAScript (JavaScript)
• Python
• Golang
• Java 8

• Match
• Substitution
• List
• Unit Tests

## Tools

"
\d[0]*\d{3}([ .-])?\d{3}([ .-])?\d{4}|\d{3}([ .-])?\d{3}([ .-])?\d{4}|\(\d{3}\)([ ])?\d{3}([.-])?\d{4}|\(\d{3}\)([ ])?\d{3}([ ])?\d{4}|\(\d{3}\)([.-])?\d{3}([.-])?\d{4}|\d{3}([ ])?\d{3}([ .-])?\d{4}
"
gm
1st Alternative
\d[0]*\d{3}([ .-])?\d{3}([ .-])?\d{4}
\d matches a digit (equivalent to [0-9])
Match a single character present in the list below
[0]
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
0 matches the character 0 with index 4810 (3016 or 608) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
1st Capturing Group
([ .-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ .-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
2nd Capturing Group
([ .-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ .-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
2nd Alternative
\d{3}([ .-])?\d{3}([ .-])?\d{4}
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
3rd Capturing Group
([ .-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ .-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
4th Capturing Group
([ .-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ .-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
3rd Alternative
\(\d{3}\)([ ])?\d{3}([.-])?\d{4}
\( matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
5th Capturing Group
([ ])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ ]
matches the character with index 3210 (2016 or 408) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
6th Capturing Group
([.-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[.-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
4th Alternative
\(\d{3}\)([ ])?\d{3}([ ])?\d{4}
\( matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
7th Capturing Group
([ ])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ ]
matches the character with index 3210 (2016 or 408) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
8th Capturing Group
([ ])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ ]
matches the character with index 3210 (2016 or 408) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
5th Alternative
\(\d{3}\)([.-])?\d{3}([.-])?\d{4}
\( matches the character ( with index 4010 (2816 or 508) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
\) matches the character ) with index 4110 (2916 or 518) literally (case sensitive)
9th Capturing Group
([.-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[.-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
10th Capturing Group
([.-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[.-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
6th Alternative
\d{3}([ ])?\d{3}([ .-])?\d{4}
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
11th Capturing Group
([ ])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ ]
matches the character with index 3210 (2016 or 408) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
{3} matches the previous token exactly 3 times
12th Capturing Group
([ .-])?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[ .-]
.-
matches a single character in the list .- (case sensitive)
\d
matches a digit (equivalent to [0-9])
{4} matches the previous token exactly 4 times
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.

r"
"
gm

Processing...