What is "The Best" U.S. Currency RegEx?
A quick search for currency regex brings up a lot of results.
The problem I have in choosing one is that regex is difficult to verify without testing all the edge cases. Does anyone have a regex for U.S. currency that has been thoroughly tested?
My only requirement is that the matched string is U.S. currency and parses to System.Decimal:
[ws][sign][digits,]digits[.fractional-digits][ws] Elements in square brackets ([ and ]) are optional. The following table describes each element. ELEMENT DESCRIPTION ws Optional white space. sign An optional sign. digits A sequence of digits ranging from 0 to 9. , A culture-specific thousands separator symbol. . A culture-specific decimal point symbol. fractional-digits A sequence of digits ranging from 0 to 9.
here's some stuff from the makers of Regex Buddy. These came from the library so i'm confident they have been thoroughly tested.
Number: Currency amount (cents mandatory) Optional thousands separators; mandatory two-digit fraction
Match; JGsoft:
^[+-]?[0-9]{1,3}(?:,?[0-9]{3})*\.[0-9]{2}$
Number: Currency amount (cents optional) Optional thousands separators; optional two-digit fraction
Match; JGsoft:
^[+-]?[0-9]{1,3}(?:,?[0-9]{3})*(?:\.[0-9]{2})?$
Number: Currency amount US & EU (cents optional) Can use US-style 123,456.78 notation and European-style 123.456,78 notation. Optional thousands separators; optional two-digit fraction
Match; JGsoft:
^[+-]?[0-9]{1,3}(?:[0-9]*(?:[.,][0-9]{2})?|(?:,[0-9]{3})*(?:\.[0-9]{2})?|(?:\.[0-9]{3})*(?:,[0-9]{2})?)$
I found this regular expression on line at www.RegExLib.com by Kirk Fuller, Gregg Durishan
I've been using it successfully for the past couple of years.
"^\$?\-?([1-9]{1}[0-9]{0,2}(\,\d{3})*(\.\d{0,2})?|[1-9]{1}\d{0,}(\.\d{0,2})?|0(\.\d{0,2})?|(\.\d{1,2}))$|^\-?\$?([1-9]{1}\d{0,2}(\,\d{3})*(\.\d{0,2})?|[1-9]{1}\d{0,}(\.\d{0,2})?|0(\.\d{0,2})?|(\.\d{1,2}))$|^\(\$?([1-9]{1}\d{0,2}(\,\d{3})*(\.\d{0,2})?|[1-9]{1}\d{0,}(\.\d{0,2})?|0(\.\d{0,2})?|(\.\d{1,2}))\)$"
Not thoroughly tested at all (I just wrote it!), but seems to behave correctly:
^-?(?:0|[1-9]\d{0,2}(?:,?\d{3})*)(?:\.\d+)?$
Test set:
0
1
33
555
4,656
4656
99,785
125,944
7,994,169
7994169
0.00
1.0
33.78795
555.12
4,656.489
99,785.01
125,944.100
-7,994,169
-7994169.23 // Borderline...
Wrong:
000
01
3,3
5.
555,
,656
99,78,5
1,25,944
--7,994,169
0.0,0
.10
33.787,95
4.656.489
99.785,01
1-125,944.1
-7,994E169
Note: Your System.Decimal is locale dependent, hard to make in regex, except perhaps when building it. I assumed digits being grouped by three, even if in some cultures (locales) there are different rules.
It is trivial to add whitespace around it.
In case you want to account for human error you could make the the regex more forgiving when matching currency. I used Keng's 2nd nice regex and made it a bit more robust to account for typo's.
\$\ ?[+-]?[0-9]{1,3}(?:,?[0-9])*(?:\.[0-9]{1,2})?
This will match any of these proper or mangled currency figures but not pick up the extra junk on the end after the space:
$46,48382
$4,648,382
$ 4,648,382
$4,648,382.20
$4,648,382.2
$4,6483,82.20
$46,48382 70.25PD
$ 46,48382 70.25PD
The answer of Keng is perfect, I just want add that for working with 1 or 2 decimals (for third version) :
"^[+-]?[0-9]{1,3}(?:[0-9]*(?:[.,][0-9]{1})?|(?:,[0-9]{3})*(?:\.[0-9]{1,2})?|(?:\.[0-9]{3})*(?:,[0-9]{1,2})?)$
NET FIDDLE: https://dotnetfiddle.net/1mUpX2