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Regex for decimal number dot instead of comma (.NET)

I am using regex to parse data from an OCR'd document and I am struggling to match the scenarios where a 1000s comma separator has been misread as a dot, and also where the dot has been misread as a comma!
So if the true value is 1234567.89 printed as 1,234,567.89 but being misread as:
1.234,567.89
1,234.567.89
1,234,567,89
etc
I could probably sort this in C# but I'm sure that a regex could do it. Any regex-wizards out there that can help?
UPDATE:
I realise this is a pretty dumb question as the regex is pretty straight forward to catch all of these, it is then how I choose to interpret the match. Which will be in C#. Thanks - sorry to waste your time on this!
I will mark the answer to Dmitry as it is close to what I was looking for. Thank you.

Please notice, that there's ambiguity since:
123,456 // thousand separator
123.456 // decimal separator
are both possible (123456 and 123.456). However, we can detect some cases:
Too many decimal separators 123.456.789
Wrong order 123.456,789
Wrong digits count 123,45
So we can set up a rule: the separator can be decimal one if it's the last one and not followed by exactly three digits (see ambiguity above), all the
other separators should be treated as thousand ones:
1?234?567?89
^ ^ ^
| | the last one, followed by two digits (not three), thus decimal
| not the last one, thus thousand
not the last one, thus thousand
Now let's implement a routine
private static String ClearUp(String value) {
String[] chunks = value.Split(',', '.');
// No separators
if (chunks.Length <= 1)
return value;
// Let's look at the last chunk
// definitely decimal separator (e.g. "123,45")
if (chunks[chunks.Length - 1].Length != 3)
return String.Concat(chunks.Take(chunks.Length - 1)) +
"." +
chunks[chunks.Length - 1];
// may be decimal or thousand
if (value[value.Length - 4] == ',')
return String.Concat(chunks);
else
return String.Concat(chunks.Take(chunks.Length - 1)) +
"." +
chunks[chunks.Length - 1];
}
Now let's try some tests:
String[] data = new String[] {
// you tests
"1.234,567.89",
"1,234.567.89",
"1,234,567,89",
// my tests
"123,456", // "," should be left intact, i.e. thousand separator
"123.456", // "." should be left intact, i.e. decimal separator
};
String report = String.Join(Environment.NewLine, data
.Select(item => String.Format("{0} -> {1}", item, ClearUp(item))));
Console.Write(report);
the outcome is
1.234,567.89 -> 1234567.89
1,234.567.89 -> 1234567.89
1,234,567,89 -> 1234567.89
123,456 -> 123456
123.456 -> 123.456

Try this Regex:
\b[\.,\d][^\s]*\b
\b = Word boundaries
containing: . or comma or digits
Not containing spaces

Responding to update/comments: you do not need regex to do this. Instead, if you can isolate the number string from the surrounding spaces, you can pull it into a string-array using Split(',','.'). Based on the logic you outlined above, you could then use the last element of the array as the fractional part, and concatenate the first elements together for the whole part. (Actual code left as an exercise...) This will even work if the ambiguous-dot-or-comma is the last character in the string: the last element in the split-array will be empty.
Caveat: This will only work if there is always a decimal point--otherwise, you would not be able to differentiate logically between a thousands-place comma and a decimal with thousandths.

How to extract address components from a string?

I have a Xamarin Forms application that uses Xamarin. Mobile on the platforms to get the current location and then ascertain the current address. The address is returned in string format with line breaks.
The address can look like this:
111 Mandurah Tce
Mandurah WA 6210
Australia
or
The Glades
222 Mandurah Tce
Mandurah WA 6210
Australia
I have this code to break it down into the street address (including number), suburb, state and postcode (not very elegant, but it works)
string[] lines = address.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
List<string> addyList = new List<string>(lines);
int count = addyList.Count;
string lineToSplit = addyList.ElementAt(count - 2);
string[] splitLine = lineToSplit.Split(null);
List<string> splitList = new List<string>(splitLine);
string streetAddress = addyList.ElementAt (count - 3).ToString ();
string postCode = splitList.ElementAt(2);
string state = splitList.ElementAt(1);
string suburb = splitList.ElementAt(0);
I would like to extract the street number, and in the previous examples this would be easy, but what is the best way to do it, taking into account the number might be Lot 111 (only need to capture the 111, not the word LOT), or 123A or 8/123 - and sometimes something like 111-113 is also returned
I know that I can use regex and look for every possible combo, but is there an elegant built-in type solution, before I go writing any more messy code (and I know that the above code isn't particularly robust)?

These simple regular expressions will account for many types of address formats, but have you considered all the possible variations, such as:
PO Box 123 suburb state post_code
Unit, Apt, Flat, Villa, Shop X Y street name
7C/94 ALISON ROAD RANDWICK NSW 2031
and that is just to get the number. You will also have to deal with all the possible types of streets such as Lane, Road, Place, Av, Parkway.
Then there are street types such as:
12 Grand Ridge Road suburb_name
This could be interpreted as street = "Grand Ridge" and suburb = "Road suburb_name", as Ridge is also a valid street type.
I have done a lot of work in this area and found the huge number of valid address patterns meant simple regexs didn't solve the problem on large amounts of data.
I ended up develpping this parser http://search.cpan.org/~kimryan/Lingua-EN-AddressParse-1.20/lib/Lingua/EN/AddressParse.pm to solve the problem. It was originally written for Australian addresses so should work well for you.

Regex can capture the parts of a match into groups. Each parentheses () defines a group.
([^\d]*)(\d*)(.*)
For "Lot 222 Mandurah Tce" this returns the following groups
Group 0: "Lot 222 Mandurah Tce" (the input string)
Group 1: "Lot "
Group 2: "222"
Group 3: " Mandurah Tce"
Explanation:
[^\d]* Any number (including 0) of any character except digits.
\d* Any number (including 0) of digits.
.* Any number (including 0) of any character.
string input = "Lot 222 Mandurah Tce";
Match match = Regex.Match(input, #"([^\d]*)(\d*)(.*)");
string beforeNumber = match.Groups[1].Value; // --> "Lot "
string number = match.Groups[2].Value; // --> "222"
string afterNumber = match.Groups[3].Value; // --> " Mandurah Tce"
If a group finds no match, match.Groups[i] will return an empty string ("") for that group.

You could check if the content starts with a number for each entry in the splitLine.
string[] splitLine = lineToSplit.Split(addresseLine);
var streetNumber = string.empty;
foreach(var s in splitLine)
{
//Get the first digit value
if (Regex.IsMatch(s, #"^\d"))
{
streetNumber = s;
break;
}
}
//Deal with empty value another way
Console.WriteLine("My streetnumber is " + s)

Yea I think you have to identify what will work.
If:
it is always in the address line and it must always start with a Digit
nothing else in that line can start with a digit (or if something else does you know which always comes in what order, ie the code below will always work if the street number is always first)
you want every contiguous character to the digit that isn't whitespace (the - and \ examples suggest that to me)
Then it could be as simple as:
var regx = new Regex(#"(?:\s|^)\d[^\s]*");
var mtch = reg.Match(addressline);
You would sort of have to sift and see if any of those assumptions are broken.

Need multiple regular expression matches using C#

So I have this list of flight data and I need to be able to parse through it using regular expressions (this isn't the entire list).
1 AA2401 F7 A4 Y7 B7 M7 H7 K7 /DFW A LAX 4 0715 0836 E0.M80 9 3:21
2 AA2421 F7 A1 Y7 B7 M7 H7 K7 DFWLAX 4 1106 1215 E0.777 7 3:09
3UA:US6352 B9 M9 H9 K0 /DFW 1 LAX 1200 1448 E0.733 1:48
For example, I might need from the first line 1, AA, 2401, and so on and so on. Now, I'm not asking for someone to come up with a regular expression for me because for the most part I'm getting to where I can pretty much handle that myself. My issue has more to do with being able to store the data some where and access it.
So I'm just trying to initially just "match" the first piece of data I need, which is the line number '1'. My "pattern" for just getting the first number is: ".?(\d{1,2}).*" . The reason it's {1,2} is because obviously once you get past 10 it needs to be able to take 2 numbers. The rest of the line is set up so that it will definitely be a space or a letter.
Here's the code:
var assembly = Assembly.GetExecutingAssembly();
var textStreamReader = new StreamReader(
assembly.GetManifestResourceStream("FlightParser.flightdata.txt"));
List<string> lines = new List<string>();
do
{
lines.Add(textStreamReader.ReadLine());
} while (!textStreamReader.EndOfStream);
Regex sPattern = new Regex(#".?(\d{1,2}).*");//whatever the pattern is
foreach (string line in lines)
{
System.Console.Write("{0,24}", line);
MatchCollection mc = sPattern.Matches(line);
if ( sPattern.IsMatch(line))
{
System.Console.WriteLine(" (match for '{0}' found)", sPattern);
}
else
{
System.Console.WriteLine();
}
System.Console.WriteLine(mc[0].Groups[0].Captures);
System.Console.WriteLine(line);
}//end foreach
System.Console.ReadLine();
With the code I'm writing, I'm basically just trying to get '1' into the match collection and somehow access it and write it to the console (for the sake of testing, that's not the ultimate goal).

Your regex pattern includes an asterisk which matches any number of characters - ie. the whole line. Remove the "*" and it will only match the "1". You may find an online RegEx tester such as this useful.

Assuming your file is not actually formatted as you posted and has each of the fields separated by something, you can match the first two-digit number of the line with this regex (ignoring 0 and leading zeros):
^\s*([1-9]\d?)
Since it is grouped, you can access the matched part through the Groups property of the Match object.
var line = "12 foobar blah 123 etc";
var re = new Regex(#"^\s*([1-9]\d?)");
var match = re.Match(line);
if (match.Success)
{
Console.WriteLine(match.Groups[1].Value); // "12"
}
else
{
Console.WriteLine("No match");
}

The following expression matches the first digit, that you wanted to capture, in the group "First".
^\s*(?<First>\d{1})
I find this regular expression tool highly useful when dealing with regex. Give it a try.
Also set RegexOption to Multiline when you are making the match.

Regular Expression to find separate words?

Here's a quickie for your RegEx wizards. I need a regular expression that will find groups of words. Any group of words. For instance, I'd like for it to find the first two words in any sentence.
Example "Hi there, how are you?" - Return would be "hi there"
Example "How are you doing?" - Return would be "How are"

Try this:
^\w+\s+\w+
Explanation: one or more word characters, spaces and more one or more word characters together.

Regular expressions could be used to parse language. Regular expressions are a more natural tool. After gathering the words, use a dictionary to see if they're actually words in a particular language.
The premise is to define a regular expression that will split out %99.9 of possible words, word being a key definition.
I assume C# is going to use a PCRE based on 5.8 Perl.
This is my ascii definition of how to split out words (expanded):
regex = '[\s[:punct:]]* (\w (?: \w | [[:punct:]](?=[\w[:punct:]]) )* )
and unicode (more has to be added/subtracted to suite specific encodings):
regex = '[\s\pP]* ([\pL\pN_-] (?: [\pL\pN_-] | \pP(?=[\pL\pN\pP_-]) )* )'
To find ALL of the words, cat the regex string into a regex (i don't know c#):
#matches =~ /$regex/xg
where /xg are the expanded and global modifiers. Note that there is only capture group 1 in the regex string so the intervening text is not captured.
To find just the FIRST TWO:
#matches =~ /(?:$regex)(?:$regex)/x
Below is a Perl sample. Anyway, play around with it. Cheers!
use strict;
use warnings;
binmode (STDOUT,':utf8');
# Unicode
my $regex = qr/ [\s\pP]* ([\pL\pN_-] (?: [\pL\pN_-] | \pP(?=[\pL\pN\pP_-]) )* ) /x;
# Ascii
# my $regex = qr/ [\s[:punct:]]* (\w (?: \w | [[:punct:]](?=[\w[:punct:]]) )* ) /x;
my $text = q(
I confirm that sufficient information and detail have been
reported in this technical report, that it's "scientifically" sound,
and that appropriate conclusion's have been included
);
print "\n**\n$text\n";
my #matches = $text =~ /$regex/g;
print "\nTotal ".scalar(#matches)." words\n",'-'x20,"\n";
for (#matches) {
print "$_\n";
}
# =======================================
my $junk = q(
Hi, there, A écafé and Horse d'oeuvre
hasn't? 'n? '? a-b? -'a-?
);
print "\n\n**\n$junk\n";
# First 2 words
#matches = $junk =~ /(?:$regex)(?:$regex)/;
print "\nFirst 2 words\n",'-'x20,"\n";
for (#matches) {
print "$_\n";
}
# All words
#matches = $junk =~ /$regex/g;
print "\nTotal ".scalar(#matches)." words\n",'-'x20,"\n";
for (#matches) {
print "$_\n";
}
Output:
**
I confirm that sufficient information and detail have been
reported in this technical report, that it's "scientifically" sound,
and that appropriate conclusion's have been included
Total 25 words
--------------------
I
confirm
that
sufficient
information
and
detail
have
been
reported
in
this
technical
report
that
it's
scientifically
sound
and
that
appropriate
conclusion's
have
been
included
**
Hi, there, A écafé and Horse d'oeuvre
hasn't? 'n? '? a-b? -'a-?
First 2 words
--------------------
Hi
there
Total 11 words
--------------------
Hi
there
A
écafé
and
Horse
d'oeuvre
hasn't
n
a-b
a-

#Rubens Farias:
Per my comment, here's the code I used:
public int startAt = 0;
private void btnGrabWordPairs_Click(object sender, EventArgs e)
{
Regex regex = new Regex(#"\b\w+\s+\w+\b"); //Start at word boundary, find one or more word chars, one or more whitespaces, one or more chars, end at word boundary
if (startAt <= txtTest.Text.Length)
{
string match = regex.Match(txtArticle.Text, startAt).ToString();
MessageBox.Show(match);
startAt += match.Length; //update the starting position to the end of the last match
}
{
Each time the button is clicked it grabs pairs of words quite nicely, proceeding through the text in the txtTest TextBox and finding the pairs sequentially until the end of the string is reached.
#sln: Thanks for the extremely detailed response!

How does this regex find triangular numbers?

Part of a series of educational regex articles, this is a gentle introduction to the concept of nested references.
The first few triangular numbers are:
1 = 1
3 = 1 + 2
6 = 1 + 2 + 3
10 = 1 + 2 + 3 + 4
15 = 1 + 2 + 3 + 4 + 5
There are many ways to check if a number is triangular. There's this interesting technique that uses regular expressions as follows:
Given n, we first create a string of length n filled with the same character
We then match this string against the pattern ^(\1.|^.)+$
n is triangular if and only if this pattern matches the string
Here are some snippets to show that this works in several languages:
PHP (on ideone.com)
$r = '/^(\1.|^.)+$/';
foreach (range(0,50) as $n) {
if (preg_match($r, str_repeat('o', $n))) {
print("$n ");
}
}
Java (on ideone.com)
for (int n = 0; n <= 50; n++) {
String s = new String(new char[n]);
if (s.matches("(\\1.|^.)+")) {
System.out.print(n + " ");
}
}
C# (on ideone.com)
Regex r = new Regex(#"^(\1.|^.)+$");
for (int n = 0; n <= 50; n++) {
if (r.IsMatch("".PadLeft(n))) {
Console.Write("{0} ", n);
}
}
So this regex seems to work, but can someone explain how?
Similar questions
How to determine if a number is a prime with regex?

Explanation
Here's a schematic breakdown of the pattern:
from beginning…
| …to end
| |
^(\1.|^.)+$
\______/|___match
group 1 one-or-more times
The (…) brackets define capturing group 1, and this group is matched repeatedly with +. This subpattern is anchored with ^ and $ to see if it can match the entire string.
Group 1 tries to match this|that alternates:
\1., that is, what group 1 matched (self reference!), plus one of "any" character,
or ^., that is, just "any" one character at the beginning
Note that in group 1, we have a reference to what group 1 matched! This is a nested/self reference, and is the main idea introduced in this example. Keep in mind that when a capturing group is repeated, generally it only keeps the last capture, so the self reference in this case essentially says:
"Try to match what I matched last time, plus one more. That's what I'll match this time."
Similar to a recursion, there has to be a "base case" with self references. At the first iteration of the +, group 1 had not captured anything yet (which is NOT the same as saying that it starts off with an empty string). Hence the second alternation is introduced, as a way to "initialize" group 1, which is that it's allowed to capture one character when it's at the beginning of the string.
So as it is repeated with +, group 1 first tries to match 1 character, then 2, then 3, then 4, etc. The sum of these numbers is a triangular number.
Further explorations
Note that for simplification, we used strings that consists of the same repeating character as our input. Now that we know how this pattern works, we can see that this pattern can also match strings like "1121231234", "aababc", etc.
Note also that if we find that n is a triangular number, i.e. n = 1 + 2 + … + k, the length of the string captured by group 1 at the end will be k.
Both of these points are shown in the following C# snippet (also seen on ideone.com):
Regex r = new Regex(#"^(\1.|^.)+$");
Console.WriteLine(r.IsMatch("aababc")); // True
Console.WriteLine(r.IsMatch("1121231234")); // True
Console.WriteLine(r.IsMatch("iLoveRegEx")); // False
for (int n = 0; n <= 50; n++) {
Match m = r.Match("".PadLeft(n));
if (m.Success) {
Console.WriteLine("{0} = sum(1..{1})", n, m.Groups[1].Length);
}
}
// 1 = sum(1..1)
// 3 = sum(1..2)
// 6 = sum(1..3)
// 10 = sum(1..4)
// 15 = sum(1..5)
// 21 = sum(1..6)
// 28 = sum(1..7)
// 36 = sum(1..8)
// 45 = sum(1..9)
Flavor notes
Not all flavors support nested references. Always familiarize yourself with the quirks of the flavor that you're working with (and consequently, it almost always helps to provide this information whenever you're asking regex-related questions).
In most flavors, the standard regex matching mechanism tries to see if a pattern can match any part of the input string (possibly, but not necessarily, the entire input). This means that you should remember to always anchor your pattern with ^ and $ whenever necessary.
Java is slightly different in that String.matches, Pattern.matches and Matcher.matches attempt to match a pattern against the entire input string. This is why the anchors can be omitted in the above snippet.
Note that in other contexts, you may need to use \A and \Z anchors instead. For example, in multiline mode, ^ and $ match the beginning and end of each line in the input.
One last thing is that in .NET regex, you CAN actually get all the intermediate captures made by a repeated capturing group. In most flavors, you can't: all intermediate captures are lost and you only get to keep the last.
Related questions
(Java) method matches not work well - with examples on how to do prefix/suffix/infix matching
Is there a regex flavor that allows me to count the number of repetitions matched by * and + (.NET!)
Bonus material: Using regex to find power of twos!!!
With very slight modification, you can use the same techniques presented here to find power of twos.
Here's the basic mathematical property that you want to take advantage of:
1 = 1
2 = (1) + 1
4 = (1+2) + 1
8 = (1+2+4) + 1
16 = (1+2+4+8) + 1
32 = (1+2+4+8+16) + 1
The solution is given below (but do try to solve it yourself first!!!!)
(see on ideone.com in PHP, Java, and C#):
^(\1\1|^.)*.$