I have a string of characters which has 0 or more occurrences of ABC = dddd within it. The dddd stands for an integer value, not necessarily four digits.
What I'd like to do is capture the integer values that occur within this pattern. I know how to perform matches with regexes but I'm new to capturing. It's not necessary to capture all the ABC integer values in one call—it's fine to loop over the string.
If this is too involved I'll just write a tiny parser, but I'd like to use regex if it's reasonably elegant. Expertise greatly appreciated.
First we need to start with a regex that matches the pattern we are looking for. This will match the example you have given (assuming ABC is alphanumeric): \w+\s*=\s*\d+
Next we need to define what we want to capture in a match by defining capture groups. .Net includes support for named capture groups, which I absolutely adore. We specify a group with (?<name for capture>expression), turning our regex into: (?<key>\w+)\s*=\s*(?<value>\d+). This gives us two captures, key and value.
Using this, we can iterate over all matches in your text:
Regex pattern = new Regex(#"(?<key>\w+)\s*=\s*(?<value>\d+)");
string body = "This is your text here. value = 1234";
foreach (Match match in pattern.Matches(body))
{
Console.WriteLine("Found key {0} with value {1}",
match.Groups.Item["key"].Value,
match.Groups.Item["value"].Value
);
}
You can use something like this:
MatchCollection allMatchResults = null;
try {
// This matches a literal '=' and then any number of digits following
Regex regexObj = new Regex(#"=(\d+)");
allMatchResults = regexObj.Matches(subjectString);
if (allMatchResults.Count > 0) {
// Access individual matches using allMatchResults.Item[]
} else {
// Match attempt failed
}
} catch (ArgumentException ex) {
// Syntax error in the regular expression
}
Based on your coment, perhaps this is more what you're after:
try {
Regex regexObj = new Regex(#"=(\d+)");
Match matchResults = regexObj.Match(subjectString);
while (matchResults.Success) {
for (int i = 1; i < matchResults.Groups.Count; i++) {
Group groupObj = matchResults.Groups[i];
if (groupObj.Success) {
// matched text: groupObj.Value
// match start: groupObj.Index
// match length: groupObj.Length
}
}
matchResults = matchResults.NextMatch();
}
} catch (ArgumentException ex) {
// Syntax error in the regular expression
}
Related
For instance in Perl I can do
$x=~/$(\d+)\s/ which is basically saying from variable x find any number preceded by $ sign and followed by any white space character. Now $1 is equal to the number.
In C# I tried
Regex regex = new Regex(#"$(\d+)\s");
if (regex.IsMatch(text))
{
// need to access matched number here?
}
First off, your regex there $(\d+)\s actually means: find a number after the end of the string. It can never match. You have to escape the $ since it's a metacharacter.
Anyway, the equivalent C# for this is:
var match = Regex.Match(text, #"\$(\d+)\s");
if (match.Success)
{
var number = match.Groups[1].Value;
// ...
}
And, for better maintainability, groups can be named:
var match = Regex.Match(text, #"\$(?<number>\d+)\s");
if (match.Success)
{
var number = match.Groups["number"].Value;
// ...
}
And in this particular case you don't even have to use groups in the first place:
var match = Regex.Match(text, #"(?<=\$)\d+(?=\s)");
if (match.Success)
{
var number = match.Value;
// ...
}
To get a matched result, use Match instead of IsMatch.
var regex = new Regex("^[^#]*#(?<domain>.*)$");
// accessible via
regex.Match("foo#domain.com").Groups["domain"]
// or use an index
regex.Match("foo#domain.com").Matches[0]
Use the Match method instead of IsMatch and you need to escape $ to match it literally because it is a character of special meaning meaning "end of string".
Match m = Regex.Match(s, #"\$(\d+)\s");
if (m.Success) {
Console.WriteLine(m.Groups[1].Value);
}
I've written a Regular expression which should validate a string using the following rules:
The first four characters must be alphanumeric.
The alpha characters are followed by 6 or 7 numeric values for a total length of 10 or 11.
So the string should look like this if its valid:
CCCCNNNNNN or CCCCNNNNNNN
C being any character and N being a number.
My expression is written: #"^[0-9A-Za-z]{3}[0-9A-Za-z-]\d{0,21}$";
My regex match code looks like this:
var cc1 = "FOOBAR"; // should fail.
var cc2 = "AAAA1111111111"; // should succeed
var regex = #"^[0-9A-Za-z]{3}[0-9A-Za-z-]\d{0,21}$";
Match match = Regex.Match( cc1, regex, RegexOptions.IgnoreCase );
if ( cc1 != string.Empty && match.Success )
{
//"The Number must start with 4 letters and contain no numbers.",
Error = SeverityType.Error
}
I'm hoping someone can take a look at my expression and offer some feedback on improvements to produce a valid match.
Also, am I use .Match() correctly? If Match.Success is true, then does that mean that the string is valid?
The regex for 4 alphanumeric characters follows by 6 to 7 decimal digits is:
var regex = #"^\w{4}\d{6,7}$";
See: Regular Expression Language - Quick Reference
The Regex.Match Method returns a Match object. The Success Property indicates whether the match is successful or not.
var match = Regex.Match(input, regex, RegexOptions.IgnoreCase);
if (!match.Success)
{
// does not match
}
The following code demonstrates the regex usage:
var cc1 = "FOOBAR"; // should fail.
var cc2 = "AAAA1111111"; // should succeed
var r = new Regex(#"^[0-9a-zA-Z]{4}\d{6,7}$");
if (!r.IsMatch(cc2))
{
Console.WriteLine("cc2 doesn't match");
}
if (!r.IsMatch(cc1))
{
Console.WriteLine("cc1 doesn't match");
}
The output will be cc1 doesn't match.
The following code is using a regular expression and checks 4 different patterns to test it, see output below:
using System;
using System.Text.RegularExpressions;
public class Program
{
public static void Main()
{
var p1 = "aaaa999999";
CheckMatch(p1);
p1 = "aaaa9999999";
CheckMatch(p1);
p1 = "aaaa99999999";
CheckMatch(p1);
p1 = "aaa999999";
CheckMatch(p1);
}
public static void CheckMatch(string p1)
{
var reg = new Regex(#"^\w{4}\d{6,7}$");
if (!reg.IsMatch(p1))
{
Console.WriteLine($"{p1} doesn't match");
}
else
{
Console.WriteLine($"{p1} matches");
}
}
}
Output:
aaaa999999 matches
aaaa9999999 matches
aaaa99999999 doesn't match
aaa999999 doesn't match
Try it as DotNetFiddle
Your conditions give:
The first four characters must be alphanumeric: [A-Za-z\d]{4}
Followed by 6 or 7 numeric values: \d{6,7}
Put it together and anchor it:
^[A-Za-z\d]{4}\d{6,7}\z
Altho that depends a bit how you define "alphanumeric". Also if you are using ignore case flag then you can remove the A-Z range from the expression.
Try the following pattern:
#"^[A-za-z\d]{4}\d{6,7}$"
Given a string
var testData = "1234 test string 987 more test";
I want to be able to use a regex to pull out 1234 and 987. As far as I could tell using
var reg = new Regex(#"?<numbers>\d+");
should do what I want but when I say
var match = reg.match(testData);
I would think that
Assert.AreEqual(match.Groups["numbers"].Captures.Count(), 2);
but it's only 1. What am I doing wrong? Intuition tells me that the
?<group>
means there can only be 0 or 1 of these values. Should I not be using a named group?
*<group>
doesn't seem to work in the regex builder in visual studio but I did not try it in my tests.
Why didn't you use the pattern string as below:
Regex reg = new Regex(#"\d+");
and then get the numbers by:
MatchCollection matches = reg.Matches(testData);
After that, the matches variable contains 2 Match value which represent for 1234 and 987.
You also use the assert as:
Assert.AreEqual(matches.Count, 2);
Hope it will help you!
try {
Regex regexObj = new Regex(#"([\d]+)", RegexOptions.IgnoreCase);
Match matchResults = regexObj.Match(subjectString);
while (matchResults.Success) {
for (int i = 1; i < matchResults.Groups.Count; i++) {
Group groupObj = matchResults.Groups[i];
if (groupObj.Success) {
// matched text: groupObj.Value
// match start: groupObj.Index
// match length: groupObj.Length
}
}
matchResults = matchResults.NextMatch();
}
} catch (ArgumentException ex) {
// Syntax error in the regular expression
}
I need to have the ability to parse out a series of numbers in a string in C# / Regex. The numbers can be one or more digits long and are always at the end of the string and after the word "ID" for example:
"Test 123 Test - ID 589"
In this case I need to be able to pick out 589.
Any suggestions? Some of the code That I have used picks out all the numbers which is not what I want to do.
Thanks
I would use the pattern #"ID (\d+)$"
using System.Text.RegularExpressions;
var s = "Test 123 Test - ID 589";
var match = Regex.Match(s, #"ID (\d+)$");
int? id = null;
if (match.Success) {
id = int.Parse(match.Groups[1].Value);
}
string resultString = null;
try {
Regex regexObj = new Regex(#"ID (?<digit>\d+)$");
resultString = regexObj.Match(subjectString).Groups["digit"].Value;
} catch (ArgumentException ex) {
// Syntax error in the regular expression
}
foo.Substring(foo.IndexOf("ID")+3)
This is the most specific pattern, in case not every line ends with a number you're interested in:
#"\bID\s+(\d+)$"
Note: Target numbers will be in capture group 1.
However, based on your description, you could just use this:
#"\d+$"
It simply looks for a string of numeric digits at the very end of each line. This is what I'd go with.
Firstly, I'm in C# here so that's the flavor of RegEx I'm dealing with. And here are thing things I need to be able to match:
[(1)]
or
[(34) Some Text - Some Other Text]
So basically I need to know if what is between the parentheses is numeric and ignore everything between the close parenthesis and close square bracket. Any RegEx gurus care to help?
This should work:
\[\(\d+\).*?\]
And if you need to catch the number, simply wrap \d+ in parentheses:
\[\((\d+)\).*?\]
Do you have to match the []? Can you do just ...
\((\d+)\)
(The numbers themselves will be in the groups).
For example ...
var mg = Regex.Match( "[(34) Some Text - Some Other Text]", #"\((\d+)\)");
if (mg.Success)
{
var num = mg.Groups[1].Value; // num == 34
}
else
{
// No match
}
Regex seems like overkill in this situation. Here is the solution I ended up using.
var src = test.IndexOf('(') + 1;
var dst = test.IndexOf(')') - 1;
var result = test.SubString(src, dst-src);
Something like:
\[\(\d+\)[^\]]*\]
Possibly with some more escaping required?
How about "^\[\((d+)\)" (perl style, not familiar with C#). You can safely ignore the rest of the line, I think.
Depending on what you're trying to accomplish...
List<Boolean> rslt;
String searchIn;
Regex regxObj;
MatchCollection mtchObj;
Int32 mtchGrp;
searchIn = #"[(34) Some Text - Some Other Text] [(1)]";
regxObj = new Regex(#"\[\(([^\)]+)\)[^\]]*\]");
mtchObj = regxObj.Matches(searchIn);
if (mtchObj.Count > 0)
rslt = new List<bool>(mtchObj.Count);
else
rslt = new List<bool>();
foreach (Match crntMtch in mtchObj)
{
if (Int32.TryParse(crntMtch.Value, out mtchGrp))
{
rslt.Add(true);
}
}
How's this? Assuming you only need to determine if the string is a match, and need not extract the numeric value...
string test = "[(34) Some Text - Some Other Text]";
Regex regex = new Regex( "\\[\\(\\d+\\).*\\]" );
Match match = regex.Match( test );
Console.WriteLine( "{0}\t{1}", test, match.Success );