So here is the string:
"DC:PPE Env:CH1 Slice:whatever to extract"
or "babaasdfsd DC:PPE asdfas Env:CH1 or Slice:whatever "
basically I am trying to find "DC:PPE" "Env:CH1" "Slice:whatever" and remove them.
I am using the following regex:(c#)
Regex r = new Regex(
#"(?:
(?<captured>(?:^|\s+)Slice|Env|Dc:.*?\s+)()
){1}
\1",
with (?:^|\s+) I am trying to match either Slice|Env|Dc appear at the beginning or have leading spaces with it.
With .*?\s+ I am trying to non-greedy match the spaces after DC:PPE.
I want it to return all three matches together.
What is wrong with this?
string combinedTestSTring = "DC:PPE Env:CH1 Slice:whatever to extract";
Regex r = new Regex(
#"(?:
(?<captured>(?:^|\s+)Slice|Env|Dc:.*?\s+)()
){1}
\1",
RegexOptions.IgnorePatternWhitespace|RegexOptions.IgnoreCase);
var a = r.Matches(combinedTestSTring);
Does this do what you want:
Regex r = new Regex(#"\b(:?Slice|Env|Dc):.+?)\b");
\b matches a word boundary. Then it matches Slice|Env|Dc followed by : and then at least one character leading up to another word boundary.
You can't return all matches together. When returning an array of matches, each element corresponds to a different capturing group in the regexp. If you have a group with a repeat count or wildcard, the returned match is just the last one found, not all of them. So you have to write a loop that walks through the input string, returning each match.
However, if you just want replace them all, r.Replace() will do that, since it replaces all the matches in the string.
Related
I tried to find a method to count a specific word in a string, and I found this.
using System.Text.RegularExpressions;
MatchCollection matches = Regex.Matches("hi, hi, everybody.", ",");
int cnt = matches.Count;
Console.WriteLine(cnt);
It worked fine, and the result shows 2.
But when I change "," to ".", it shows 18, not the expected 1. Why?
MatchCollection matches = Regex.Matches("hi, hi, everybody.", ".");
and when I change "," to "(", it shows me an error!
the error reads:
SYSTEM.ARGUMENTEXCEPTION - THERE ARE TOO MANY (...
I don't understand why this is happening
MatchCollection matches = Regex.Matches("hi( hi( everybody.", "(");
Other cases seem to work fine but I need to count "(".
The first instance, with the ., is using a special character which has a different meaning in regular expressions. It is matching ALL of the characters you have; hence you getting a result of 18.
http://www.regular-expressions.info/dot.html
To match an actual "." character, you'll need to "escape" it so that it is read as a full-stop and not a special character.
MatchCollection matches = Regex.Matches("hi, hi, everybody.", "\.");
The same exists for the ( character. It's a special character that has a different meaning in terms of regular expressions and you will need to escape it.
MatchCollection matches = Regex.Matches("hi( hi( everybody.", "\(");
Looks like you're new to regular expressions so I'd suggest reading, the link I posted above is a good start.
HOWEVER!
If you are looking to just count ocurences in a string, you don't need regex.
How would you count occurrences of a string within a string?
If you're using .NET 3.5 you can do this in a one-liner with LINQ:
int cnt = source.Count(f => f == '(');
If you don't want to use LINQ you can do it with:
int cnt = source.Split('(').Length - 1;
The second parameter represents a pattern, not necessarily just a character to search for in your string, and the ( by itself is an invalid pattern.
You don't need Regex to count occurrences of a character. Just use LINQ's Count():
var input = "hi( hi( everybody.";
var occurrences = input.Count(x => x == '('); // 2
( character is a special character which means start of a group. If you need to use ( as literal you need to escape it with \(. That should solve your problem.
I tried to create a regular expression which pulls everything that matches:
[aA-zZ]{2}[0-9]{5}
The problem is that I want to exclude from matching when I have eg. ABCD12345678
Can anyone help me resolve this?
EDIT1:
I am looking two letters and five digits in the string, but I want to exclude from matching when I have string like ABCD12345678, because when I use above regular expression it will return CD12345.
EDIT2:
I didn't check everything but I think I found answer:
WHEN field is null then field
WHEN fnRegExMatch(field, '[a-zA-Z]{2}[0-9]{5}') = 'N/A' THEN field
WHEN field like '%[^a-z][a-z][a-z][0-9][0-9][0-9][0-9][0-9][^0-9]%' or field like '[a-z][a-z][0-9][0-9][0-9][0-9][0-9][^0-9]%' THEN fnRegExMatch(field, '[a-zA-Z]{2}[0-9]{5}')
ELSE field
First [aA-zZ] haven't any sense, second use word boundaries:
\b[a-zA-Z]{2}[0-9]{5}\b
You could also use case insensitive modifier:
(?i)\b[a-z]{2}[0-9]{5}\b
According to your comment, it seems you may have underscore after the five digits. In this case, word boundary doesn't work, you have to use ths instead:
(?i)(?<![a-z])([a-z]{2}[0-9]{5})(?![0-9])
(?<![a-z]) is a negative lookbehind that assumes you haven't a letter before the two that are mandatory
(?![0-9]) is a negative lookahead that assumes you haven't a digit after the five that are mandatory
This would be the code, along with usage samples.
public static Regex regex = new Regex(
"\\b[a-zA-Z]{2}\\d{5}\\b",
RegexOptions.CultureInvariant
| RegexOptions.Compiled
);
//// Replace the matched text in the InputText using the replacement pattern
// string result = regex.Replace(InputText,regexReplace);
//// Split the InputText wherever the regex matches
// string[] results = regex.Split(InputText);
//// Capture the first Match, if any, in the InputText
// Match m = regex.Match(InputText);
//// Capture all Matches in the InputText
// MatchCollection ms = regex.Matches(InputText);
//// Test to see if there is a match in the InputText
// bool IsMatch = regex.IsMatch(InputText);
//// Get the names of all the named and numbered capture groups
// string[] GroupNames = regex.GetGroupNames();
//// Get the numbers of all the named and numbered capture groups
// int[] GroupNumbers = regex.GetGroupNumbers();
I am trying to replace all characters inside a Regular Expression expect the number, but the number should not start with 0
How can I achieve this using Regular Expression?
I have tried multiple things like #"^([1-9]+)(0+)(\d*)"and "(?<=[1-9])0+", but those does not work
Some examples of the text could be hej:\\\\0.0.0.22, hej:22, hej:\\\\?022 and hej:\\\\?22, and the result should in all places be 22
Rather than replace, try and match against [1-9][0-9]*$ on your string. Grab the matched text.
Note that as .NET regexes match Unicode number characters if you use \d, here the regex restricts what is matched to a simple character class instead.
(note: regex assumes matches at end of line only)
According to one of your comments hej:\\\\0.011.0.022 should yield 110022. First select the relevant string part from the first non zero digit up to the last number not being zero:
([1-9].*[1-9]\d*)|[1-9]
[1-9] is the first non zero digit
.* are any number of any characters
[1-9]\d* are numbers, starting at the first non-zero digit
|[1-9] includes cases consisting of only one single non zero digit
Then remove all non digits (\D)
Match match = Regex.Match(input, #"([1-9].*[1-9]\d*)|[1-9]");
if (match.Success) {
result = Regex.Replace(match.Value, "\D", "");
} else {
result = "";
}
Use following
[1-9][0-9]*$
You don't need to do any recursion, just match that.
Here is something that you can try The87Boy you can play around with or add to the pattern as you like.
string strTargetString = #"hej:\\\\*?0222\";
string pattern = "[\\\\hej:0.?*]";
string replacement = " ";
Regex regEx = new Regex(pattern);
string newRegStr = Regex.Replace(regEx.Replace(strTargetString, replacement), #"\s+", " ");
Result from the about Example = 22
Capturing a repetition group is always returning the last element but that is not quite helpfull. For example:
var regex = new RegEx("^(?<somea>a)+$");
var match = regex.Match("aaa");
match.Group["somea"]; // return "a"
I would like to have a collection of match element instead of the last match item.
Is that possible?
CaptureCollection
You can use CaptureCollection which represents the set of captures made by a single capturing group.
If a quantifier is not applied to a capturing group, the CaptureCollection includes a single Capture object that represents the same captured substring as the Group object.
If a quantifier is applied to a capturing group, the CaptureCollection includes one Capture object for each captured substring, and the Group object provides information only about the last captured substring.
So you can do this
var regex = new Regex("^(?<somea>a)+$");
var match = regex.Match("aaa");
List<string> aCaptures=match.Groups["somea"]
.Captures.Cast<Capture>()
.Select(x=>x.Value)
.ToList<string>();
//aCaptures would now contain a list of a
Take a look in the Captures collection:
match.Groups["somea"].Captures
You can also try something like this :
var regex = new RegEx("^(?<somea>a)+$");
var matches = regex.Matches("aaa");
foreach(Match _match in matches){
match.Group["somea"]; // return "a"
}
This is just a sample but it should give a good start.
I did not check the validity of your regular expression though
You must use the quantifier + to the thing you want to match, not the group, if you quantify the group that will create as many groups as matches are.
So (a)+ in aaa Will create 1 group and will replace the match with the new occurrence of the match and (a+) will create 1 group with aaa
So you know what to do with your problem, just move the + inside the capturing group.
I am a complete newb when it comes to regex, and would like help to make an expression to match in the following:
{ValidFunctionName}({parameter}:"{value}")
{ValidFunctionName}({parameter}:"{value}",
{parameter}:"{value}")
{ValidFunctionName}()
Where {x} is what I want to match, {parameter} can be anything $%"$ for example and {value} must be enclosed in quotation marks.
ThisIsValid_01(a:"40")
would be "ThisIsValid_01", "a", "40"
ThisIsValid_01(a:"40", b:"ZOO")
would be "ThisIsValid_01", "a", "40", "b", "ZOO"
01_ThisIsntValid(a:"40")
wouldn't return anything
ThisIsntValid_02(a:40)
wouldn't return anything, as 40 is not enclosed in quotation marks.
ThisIsValid_02()
would return "ThisIsValid_02"
For a valid function name I came across: "[A-Za-z_][A-Za-z_0-9]*"
But I can't for the life of me figure out how to match the rest.
I've been playing around on http://regexpal.com/ to try to get valid matches to all conditions, but to no avail :(
It would be nice if you kindly explained the regex too, so I can learn :)
EDIT: This will work, uses 2 regexs. The first get the function name and everything inside it, the second extracts each pair of params and values from what's inside the function's brackets. You cannot do this with a single regex. Add some [ \t\n\r]* for whitespace.
Regex r = new Regex(#"(?<function>\w[\w\d]*?)\((?<inner>.*?)\)");
Regex inner = new Regex(#",?(?<param>.+?):""(?<value>[^""]*?)""");
string input = "_test0(a:\"lolololol\",b:\"2\") _test1(ghgasghe:\"asjkdgh\")";
List<List<string>> matches = new List<List<string>>();
MatchCollection mc = r.Matches(input);
foreach (Match match in mc)
{
var l = new List<string>();
l.Add(match.Groups["function"].Value);
foreach (Match m in inner.Matches(match.Groups["inner"].Value))
{
l.Add(m.Groups["param"].Value);
l.Add(m.Groups["value"].Value);
}
matches.Add(l);
}
(Old) Solution
(?<function>\w[\w\d]*?)\((?<param>.+?):"(?<value>[^"]*?)"\)
(Old) Explanation
Let's remove the group captures so it is easier to understand: \w[\w\d]*?\(.+?:"[^"]?"\)
\w is the word class, it is short for [a-zA-Z_]
\d is the digit class, it is short for [0-9]
\w[\w\d]*? Makes sure there is valid word character for the start of the function, and then matches zero or more further word or digit characters.
\(.+? Matches a left bracket then one or more of any characters (for the parameter)
:"[^"]*?"\) Matches a colon, then the opening quote, then zero or more of any character except quotes (for the value) then the close quote and right bracket.
Brackets (or parens, as some people call them) as escaped with the backslashes because otherwise they are capturing groups.
The (?<name> ) captures some text.
The ? after each the * and + operators makes them non-greedy, meaning that they will match the least, rather than the most, amount of text.
(Old) Use
Regex r = new Regex(#"(?<function>\w[\w\d]*?)\((?<param>.+?):""(?<value>[^""]*?)""");
string input = "_test0(aa%£$!:\"lolololol\") _test1(ghgasghe:\"asjkdgh\")";
List<string[]> matches = new List<string[]>();
if(r.IsMatch(input))
{
MatchCollection mc = r.Matches(input);
foreach (Match match in mc)
matches.Add(new[] { match.Groups["function"].Value, match.Groups["param"].Value, match.Groups["value"].Value });
}
EDIT: Now you've added an undefined number of multiple parameters, I would recommend making your own parser rather than using regexs. The above example only works with one parameter and strictly no whitespace. This will match multiple parameters with strict whitespace but will not return the parameters and values:
\w[\w\d]*?\(.+?:"[^"]*?"(,.+?:"[^"]*?")*\)
Just for fun, like above but with whitepace:
\w[\w\d]*?[ \t\r\n]*\([ \t\r\n]*.+?[ \t\r\n]*:[ \t\r\n]*"[^"]*?"([ \t\r\n]*,[ \t\r\n]*.+?[ \t\r\n]*:[ \t\r\n]*"[^"]*?")*[ \t\r\n]*\)
Capturing the text you want will be hard, because you don't know how many captures you are going to have and as such regexs are unsuited.
Someone else has already given an answer that gives you a flat list of strings, but in the interest of strong typing and proper class structure, I’m going to provide a solution that encapsulates the data properly.
First, declare two classes:
public class ParamValue // For a parameter and its value
{
public string Parameter;
public string Value;
}
public class FunctionInfo // For a whole function with all its parameters
{
public string FunctionName;
public List<ParamValue> Values;
}
Then do the matching and populate a list of FunctionInfos:
(By the way, I’ve made some slight fixes to the regexes... it will now match identifiers correctly, and it will not include the double-quotes as part of the “value” of each parameter.)
Regex r = new Regex(#"(?<function>[\p{L}_]\w*?)\((?<inner>.*?)\)");
Regex inner = new Regex(#",?(?<param>.+?):""(?<value>[^""]*?)""");
string input = "_test0(a:\"lolololol\",b:\"2\") _test1(ghgasghe:\"asjkdgh\")";
var matches = new List<FunctionInfo>();
if (r.IsMatch(input))
{
MatchCollection mc = r.Matches(input);
foreach (Match match in mc)
{
var l = new List<ParamValue>();
foreach (Match m in inner.Matches(match.Groups["inner"].Value))
l.Add(new ParamValue
{
Parameter = m.Groups["param"].Value,
Value = m.Groups["value"].Value
});
matches.Add(new FunctionInfo
{
FunctionName = match.Groups["function"].Value,
Values = l
});
}
}
Then you can access the collection nicely with identifiers like FunctionName:
foreach (var match in matches)
{
Console.WriteLine("{0}({1})", match.FunctionName,
string.Join(", ", match.Values.Select(val =>
string.Format("{0}: \"{1}\"", val.Parameter, val.Value))));
}
Try this:
^\s*(?<FunctionName>[A-Za-z][A-Za-z_0-9]*)\(((?<parameter>[^:]*):"(?<value>[^"]+)",?\s*)*\)
^\s*(?<FunctionName>[A-Za-z][A-Za-z_0-9]*) matches the function name, ^ means start of the line, so that the first character in string must match. You can keep you remove the whitespace capture if you don't need it, I just added it to make the match a little more flexible.
The next set \(((?<parameter>[^:]*):"(?<value>[^"]+)",?)*\) means capture each parameter-value pair inside the parenthesis. You have to escape the parenthesis for the function since they are symbols within the regex syntax.
The ?<> inside parenthesis are named capture groups, which when supported by a library, as they are in .NET, make grabbing the groups in the matches a little easier.
Here:
\w[\w\d]*\s*\(\s*(?:(\w[\w\d]*):("[^"]*"|\d+))*\s*\)
Visualization of that regex here.
For Problems like that I always suggest people not to "find" a single regex but to write multiple regex sharing the work.
But here is my quick shot:
(?<funcName>[A-Za-z_][A-Za-z_0-9]*)
\(
(?<ParamGroup>
(?<paramName>[^(]+?)
:
"(?<paramValue>[^"]*)"
((,\s*)|(?=\)))
)*
\)
The whitespaces are there for better readability. Remove them or set the option to ignore pattern whitespaces.
This regex passes all your test cases:
^(?<function>[A-Za-z][\w]*?)\(((?<param>[^:]*?):"(?<value>[^"]*?)",{0,1}\s*)*\)$
This works on multiple parameters and no parameters. It also handles special characters in the param name and whitespace after the comma. There may need to be some adjustments as your test cases do not cover everything you indicate in your text.
Please note that \w usually includes digits and is not appropriate as the leading character of the function name. Reference: http://www.regular-expressions.info/charclass.html#shorthand