Regex to match dollar amount with uppercase letter or word

I’m trying to match some sort of amount, here are all possibilities:

$5.6 million
$4,1 million
$8,1M
$6.3M
$333,333
$2 million
$5 million

I have already this regex:

$d{1,3}(?:,d{3})*(?:s+(?:thousand|[mb]illion|[MB]illion)|[M])?

See online demo.

But I’m not able to match those ones:

$5.6 million
$4,1 million
$8,1M
$6.3M

Any help would be appreciated.

Answers:

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Method 1

Let’s look at your regular expression:

$d{1,3}(?:,d{3})*(?:s+(?:thousand|[mb]illion|[MB]illion)|[M])?

$d{1,3} is fine. What follows? One way to answer that is to consider the following three possibilities.

The string to be matched ends ' million'

This string (which begins with a space, in case you missed that) is preceded by an empty string or a single digit preceded by a comma or period:

(?:[,.]d)? million

Evidently, “million” can be “thousand” or “billion”, and the first in last might be capitalized, so we change the expression to

(?:[,.]d)? (?:[MmBb]illion|thousand)

One potential problem is that this matches '$5.6 millionaire'. We can avoid that problem by tacking on a word boundary preventing the match to be followed by a word character:

(?:[,.]d)? (?:[MmBb]illion|thousand)b

The string ends 'M'

In this case the 'M' must be preceded by a single digit preceded by a comma or period:

[,.]dMb

You could accept 'B' as well by changing M to [MB].

The string ends with three digits preceded by a comma

Here we need

,d{3}b

Here the word boundary avoids matching, for example, $333,3333'. It will not match, however, '$333,333,333' or '$333,333,333,333'. If we want to match those we could change the expression to

(?:,d{3})+b

or to match '$333' as well, change it to

(?:,d{3})*b

Construct the alternation

We therefore can use the following regular expression.

$d{1,3}(?:(?:[,.]d)? (?:[MmBb]illion|thousand)b|[,.]dMb|,d{3}b)

Factoring out the end-of-string anchor we obtain

$d{1,3}(?:(?:[,.]d)? (?:[MmBb]illion|thousand)|[,.]dM|,d{3})b

Demo

Method 2

You can use

(?i)$d+(?:[.,]d+)*(?:s+(?:thousand|[mb]illion)|m)?

If you need to make sure you do not match m that is part of another word:

(?i)$d+(?:[.,]d+)*(?:s+(?:thousand|[mb]illion)|m)?b

See the regex demo. Details:

• (?i) – case insensitive option
• $ – a $ char
• d+ – one or more digits
• (?:[.,]d+)* – zero or more repetitions of . or , and then one or more digits
• (?:s+(?:thousand|[mb]illion)|m)? – an optional occurrence of
  • s+(?:thousand|[mb]illion) – one or more whitespaces and then thousand, million or billion
  • | – or
  • m – an m char
• b – a word boundary.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0