CODEWITHSUNDEEP
c#regex
robr
robr

Reputation: 959

Currency Range Regular Expression

I'm trying to find ranges of properly formatted currency or numbers in a string with regular expressions. I happen to be using C#, so the regex is formatted that way.

For example, I want to be able to find:

$10,000,000 to $20M
$10k-$20k
100.23k - 200.34k
$20000 and $500600
3456646 to 4230405

It should not match on:

$10,0000,000 to $20,000,000 //extra zero in first number
20k xyz 40k //middle string does not match a range word

Here is my regular expression so far:

(^|\s|\$)([1-9](?:\d*|(?:\d{0,2})(?:,\d{3})*)(?:\.\d*[1-9])?|0?\.\d*[1-9]|0)(|m|k)(?:|\s)(?:|to|and|-|,)(?:|\s)(|\$)([1-9](?:\d*|(?:\d{0,2})(?:,\d{3})*)(?:\.\d*[1-9])?|0?\.\d*[1-9]|0)(\s|m|k)

It seems to be working fairly well, but sometimes matches items I don't expect it to. Examples:

1985 xyz 1999 //2 matches, both numbers without xyz
$10,000,000 xyz $20000000 //1 match on the $2000000
$10,000,0000 to $20,000,000 //1 match on the $10,000,0000 (extra zero on end)

What am I missing? Is it foolish to do this with regex?

Upvotes: 4

Views: 1047

Answers (1)

Lodewijk Bogaards
Lodewijk Bogaards

Reputation: 19987

Here you go buddy

(?<=^|\s)\$?\d+((\.\d{2})?(k|M)|(,\d{3})*)\b\s*(to|-|and )\s*\$?\d*((\.\d{2})?(k|M)|(,\d{3})*)(\s|$)

see it in action.

This part 

\d+((\.\d{2})?(k|M)|(,\d{3})*)

is repeating itself. So better save that in a constant and concat this regex together.

String moneyPattern = @"\d+((\.\d{2})?(k|M)|(,\d{3})*)";
String rangeConnectorPattern = @"\b\s*(to|-|and\b)\s*";
String moneyRangePattern = @"(?<=^|\s)"+ 
    moneyPattern + rangeConnectorPattern +  moneyPattern +
    "(\s|$)";

No need to write a parser.

Upvotes: 2

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