Regular Expressions 101

Explanation

Pro

Definition Group(?(DEFINE) (?<currency_symbol> \p{Sc} ) (?<leading_group> [1-9] \d{0,2}+ ) (?<group> \d{3}+ ) (?<non_leading_groups> (?&group) (?:(?&group_delim)(?&group))*+ ) (?<decimal_delim> (?# Use the opposite of group_delim. ) (?(group_delim_comma) \. | (?(group_delim_period) , | [,.] (?# There's no definitive grouping_delim. ) ) ) ) )

Group currency_symbol(?<currency_symbol> \p{Sc} )

\p{Sc}any currency sign

Group leading_group(?<leading_group> [1-9] \d{0,2}+ )

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d{0,2}+a Unicode decimal digit, repeated between 0 and 2 times

Group group(?<group> \d{3}+ )

\d{3}+a Unicode decimal digit, repeated exactly 3 times

Group non_leading_groups(?<non_leading_groups> (?&group) (?:(?&group_delim)(?&group))*+ )

(?&group)calls group group as a subroutine

Non-Capturing Group(?:(?&group_delim)(?&group))*+

*+repeats the group contents below any number of times:

(?&group_delim)calls group group_delim as a subroutine

(?&group)calls group group as a subroutine

Group decimal_delim(?<decimal_delim> (?# Use the opposite of group_delim. ) (?(group_delim_comma) \. | (?(group_delim_period) , | [,.] (?# There's no definitive grouping_delim. ) ) ) )

Comment: Use the opposite of group_delim.

Condition(?(group_delim_comma) \. | (?(group_delim_period) , | [,.] (?# There's no definitive grouping_delim. ) ) )

Uses the first branch if group group_delim_comma matched

If the condition is true, match this branch: \.

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Otherwise, match this branch: (?(group_delim_period) , | [,.] (?# There's no definitive grouping_delim. ) )

Condition(?(group_delim_period) , | [,.] (?# There's no definitive grouping_delim. ) )

Uses the first branch if group group_delim_period matched

If the condition is true, match this branch: ,

, the literal text ,

Otherwise, match this branch: [,.] (?# There's no definitive grouping_delim. )

Character Class[,.]

,the literal , (44₁₀ / 54₈ / 2C₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Comment: There's no definitive grouping_delim.

^start of line

Atomic Group(?> (?&currency_symbol) (?&leading_group) (?: (?<group_delim> (?<group_delim_comma> , ) | (?<group_delim_period> \. ) | \ (?# Allow whitespace as a delimiter. ) ) (?&non_leading_groups) | \d*+ (?# It's also possible that there's no delimiter. ) ) )

(?&currency_symbol)calls group currency_symbol as a subroutine

(?&leading_group)calls group leading_group as a subroutine

Non-Capturing Group(?: (?<group_delim> (?<group_delim_comma> , ) | (?<group_delim_period> \. ) | \ (?# Allow whitespace as a delimiter. ) ) (?&non_leading_groups) | \d*+ (?# It's also possible that there's no delimiter. ) )

1st Alternative (?<group_delim> (?<group_delim_comma> , ) | (?<group_delim_period> \. ) | \ (?# Allow whitespace as a delimiter. ) ) (?&non_leading_groups)

Group group_delim(?<group_delim> (?<group_delim_comma> , ) | (?<group_delim_period> \. ) | \ (?# Allow whitespace as a delimiter. ) )

1st Alternative (?<group_delim_comma> , )

Group group_delim_comma(?<group_delim_comma> , )

, the literal text ,

2nd Alternative (?<group_delim_period> \. )

Group group_delim_period(?<group_delim_period> \. )

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

3rd Alternative \ (?# Allow whitespace as a delimiter. )

\ the literal (32₁₀ / 40₈ / 20₁₆)

Comment: Allow whitespace as a delimiter.

(?&non_leading_groups)calls group non_leading_groups as a subroutine

2nd Alternative \d*+ (?# It's also possible that there's no delimiter. )

\d*+a Unicode decimal digit, repeated any number of times

Comment: It's also possible that there's no delimiter.

Non-Capturing Group(?: (?&decimal_delim) \d*+ )?+

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

u modifier: unicode. Treats the pattern and subject as UTF-16

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

(?(DEFINE)
  (?<currency_symbol> \p{Sc} )
  (?<leading_group> [1-9] \d{0,2}+ )
  (?<group> \d{3}+ )
  (?<non_leading_groups> (?&group) (?:(?&group_delim)(?&group))*+ )
  (?<decimal_delim>
    (?# Use the opposite of group_delim. )
    (?(group_delim_comma)
      \.
      | (?(group_delim_period)
        ,
        | [,.] (?# There's no definitive grouping_delim. )
      )
    )
  )
)

^
(?>
  (?&currency_symbol)
  (?&leading_group)
  (?:
    (?<group_delim>
      (?<group_delim_comma> , ) |
      (?<group_delim_period> \. ) |
      \  (?# Allow whitespace as a delimiter. )
    )
    (?&non_leading_groups)
    | \d*+ (?# It's also possible that there's no delimiter. )
  )
)
(?:
  (?&decimal_delim)
  \d*+
)?+
$

New

Here's the same regex in a convenient one-liner:
/^(?>\p{Sc}[1-9]\d{0,2}+(?:(?<gd>(?<gdc>,)|(?<gdp>\.)|\ )\d{3}+(?:(?&gd)\d{3}+)*+|\d*+))(?:(?(gdc)\.|(?(gdp),|[,.]))\d*+)?+$/u

We want to match these:
$1
$10
$100
$1000
$1,000
$10,000
$100,000
$1,000,000
$1.00
$100.00
$10,000.00
$1,000,000.00
$1.000.000,00
$1.000
$1.000.000
$1,00
$1.000,00
$10000000000000
$100000000000.00000
$100000000000,00000

We don't want to match these:
$1,000,00
$1,00,00
$1.00.000

A few different currency symbols that we want to match:
$1
¢1
£1
¤1
¥1
₠1
₡1
₢1
₣1
₤1
₥1
₦1
₧1
₩1
₪1
₫1
€1
₭1
₮1
₯1
₰1
₱1
₲1
₳1
₴1
₵1
₶1
₷1
₸1
₹1
₺1
₻1
₼1
₽1

Nearby symbols that share some bytes (UTF-8) that we don't want to match:
¡1
¦1
§1
©1
ₔ1

Extraction

Here's the same regex in a convenient one-liner:
/^(?>\p{Sc}[1-9]\d{0,2}+(?:(?<gd>(?<gdc>,)|(?<gdp>\.)|\ )\d{3}+(?:(?&gd)\d{3}+)*+|\d*+))(?:(?(gdc)\.|(?(gdp),|[,.]))\d*+)?+$/u

We want to match these:
$1
$10
$100
$1000
$1,000
$10,000
$100,000
$1,000,000
$1.00
$100.00
$10,000.00
$1,000,000.00
$1.000.000,00
$1.000
$1.000.000
$1,00
$1.000,00
$10000000000000
$100000000000.00000
$100000000000,00000

We don't want to match these:
$1,000,00
$1,00,00
$1.00.000

A few different currency symbols that we want to match:
$1
¢1
£1
¤1
¥1
₠1
₡1
₢1
₣1
₤1
₥1
₦1
₧1
₩1
₪1
₫1
€1
₭1
₮1
₯1
₰1
₱1
₲1
₳1
₴1
₵1
₶1
₷1
₸1
₹1
₺1
₻1
₼1
₽1

Nearby symbols that share some bytes (UTF-8) that we don't want to match:
¡1
¦1
§1
©1
ₔ1