New dad, so my eyes are tired and I'm trying to figure out why this code:
var regex = new Regex(#"(https:)?\/");
Console.WriteLine (regex.Replace("https://foo.com", ""));
Emits:
foo.com
I only have the one forward slash, so why are both being captured in the group for the replacement?
Regex.Replace:
In a specified input string, replaces all strings that match a regular expression pattern with a specified replacement string.
Every single / matches the regular expression pattern #"(https:)?\/". If you try e.g. "https://foo/./com/", all /s would be removed.
If you check what matches are generated, it becomes clear. Add this to your code:
var matches = regex.Matches("https://foo.com");
foreach (Match match in matches)
{
Console.WriteLine(match.Value);
}
And you'll see that https:/ is matched and replaced, / is matched and replaced (because https:is optional) and foo.com remains.
Related
I'm reading from a file, and need to find a string that is encapsulated by two identical non-ascii values/control seperators, in this case 'RS'
How would I go about doing this? Would I need some form of regex?
RS stands for Record Separator, and it has a value of 30 (or 0x1E in hexadecimal). You can use this regular expression:
\x1E([\w\s]*?)\x1E
That matches the RS, then matches any letter, number or space, and then again the RS. The ? is to make the regex match as less characters as possible, in case there are more RS characters afterwards.
If you prefer not to match numbers, you could use [a-zA-Z\s] instead of [\w\s].
Example:
string fileContents = "Something \u001Eyour string\u001E more things \u001Eanother text\u001E end.";
MatchCollection matches = Regex.Matches(fileContents, #"\x1E([\w\s]*?)\x1E");
if (matches.Count == 0)
return; // Not found, display an error message and exit.
foreach (Match match in matches)
{
if (match.Groups.Count > 1)
Console.WriteLine(match.Groups[1].Value);
}
As you can see, you get a collection of Match, and each match.Value will have the whole matched string including the separators. match.Groups will have all matched groups, being the first one again the whole matched string (that's by default) and then each of your groups (those between parenthesis). In this case, you only have one in your regex, so you just need the second one on that list.
Using regex you can do something like this:
string pattern = string.Format("{0}(.*){1}",firstString,secondString);
var matches = Regex.Matches(myString, pattern);
foreach (Match match in matches)
{
foreach (Capture capture in match.Captures)
{
//Do stuff, with the current you should remove firstString and secondString from the capture.Value
}
}
After that use Regex.match to find the string that match with the pattern built before.
Remember to escape all the special char for regex.
You can use Regex.Matches, I'm using X as the separator in this example:
var fileContents = "Xsomething1X Xsomething2X Xsomething3X";
var results = Regex.Matches(fileContents, #"(X).*?(\1)");
The you can loop on results to do anything you want with the matches.
The \1 in the regex means "reference first group". I've put X between () so it is going to be group 1, the I use \1 to say that the match in this place should be exactly the same as the group 1.
You don't need a regular expression for that.
Read the contents of the file (File.ReadAllText).
Split on the separator character (String.Split).
If you know there's only one occurrence of your string, take the second array element (result[1]). Otherwise, take every other entry (result.Where((x, i) => i % 2 == 1)).
Using DirectoryServices.AccountManagement I'm getting users DistinguishedName which looks like so:
CN=Adam West,OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu
I need to get first OU value from this.
I found similar solution: C# Extracting a name from a string
And using some tweaks I created this code:
string input = #"CN=Adam West,OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu";
Match m = Regex.Match(input, #"OU=([a-zA-Z\\]+)\,.*$");
Console.WriteLine(m.Groups[1].Value);
This code returns STORE as expected, but if I change Groups[1] to Groups[0] I get almost same result as input string:
OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu
How can I change this regex so it will return only values of OU? SO that in this example I get array of 2 matches. If I would have more OU in my string then array would be longer.
EDIT:
I've converted my code (using #dasblinkenlight suggestions) into function:
private static List<string> GetOUs()
{
var input = #"CN=Adam West,OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu";
var mm = Regex.Matches(input, #"OU=([a-zA-Z\\]+)");
return (from Match m in mm select m.Groups[1].Value).ToList();
}
Is that correct?
Your regular expression is fine (almost), you are just using a wrong API.
Remove the parts of the regexp that match up to the ending anchor $, and change the call of Match for a call of Matches, and get the matches in a loop, like this:
var input = #"CN=Adam West,OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu";
var mm = Regex.Matches(input, #"OU=([a-zA-Z\\]+)");
foreach (Match m in mm)
Console.WriteLine(m.Groups[1].Value);
}
Your existing regex:
#"OU=([a-zA-Z\\]+)\,.*$"
Matches OU=, then some letters and backslashes ([a-zA-Z\\]+), then a comma, then any characters (.*) to the end of the line ($).
Thus a single match will always match the entire line after the first OU section.
Modify your regex by removing the ,.*$ at the end, at it will match each OU group:
#"OU=([a-zA-Z\\]+)"
Also note that the parentheses are a capturing group. They are useful if you also want to capture just the value part by itself, but if you are not using that, they are not necessary, and you can just have this:
#"OU=[a-zA-Z\\]+"
It's beacuse you are mixing up matches and groups
string input = #"CN=Adam West,OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu";
MatchCollection mc = Regex.Matches(input, #"OU=([a-zA-Z\\]+),");
foreach(Match m in mc)
{
Console.WriteLine(m.Result("$1"));
}
Group[0] returns the full match:
Group[1] returns the first Pattern in the match [i.e. everything in the first parenthesis '(' ')' ]
So if you wanted to get exactly those 2 occurances of OU.. you could do this:
Match m = Regex.Match(input, #"OU=([a-zA-Z\\]+)\,OU=([a-zA-Z\\]+)\,.*$");
Console.WriteLine(m.Groups[1].Value);
Console.WriteLine(m.Groups[2].Value);
Group[0] returns the full match: (which you don't want)
Group[1] returns the first Pattern in the match [i.e everything in the first parenthesis '(' ')' ]
Group[2] returns the second Pattern in the match [i.e. everything in the second parenthesis '(' ')' ]
Giving:
STORE
COMPANY
But I'm assuming you don't want to be so explicit with your Regex for each Pattern you are interested in.
If you want to get multiple matches, then you need to do Regex's Matches call that returns a Matchcollection.
MatchCollection ms = Regex.Matches(...);
This still won't work with your current Regex though, because everything from STORE so the end of the line will be in the first match. If you only want to get the pattern "1-or-more-letters" after a "OU="
You only need:
#"OU=([a-zA-Z\\]+)"
So your code would be:
string input = #"CN=Adam West,OU=STORE,OU=COMPANY,DC=mycompany,DC=group,DC=eu";
MatchCollection ms = Regex.Matches(input, #"OU=([a-zA-Z\\]+)");
foreach (Match m in ms)
{
Console.WriteLine(m.Groups[1].Value);// get the string in the first "(" ")"
}
I have a problem when I want to capture the value using Capture function in C#.
My code looks for many patterns in a string, so I use match collection, then for each match I use Capture function. But when I want to replace the captureOut.value it does not work.
My code:
MatchCollection matches = Regex.Matches(string, #"\d*\.*\d+\s")
foreach (Match matchOut in matches)
{
foreach (Capture captureOut in matchOut.Captures)
Match match1 = Regex.Match(captureOut.Value, #"\d*\.*\d+");
::::: //}
output = Regex.Replace(output,captureOut.Value, Function1);
}
// i change the value of pattern based on the output of function 1
This part of my code, I do not know why capture out.value does not work.
Using the capture property only makes sense if you have groups in your regex, i.e. parts of your regex enclosed in ( ).
Since your regex has no, there is only one captured group and it's the whole string that matches the regex.
I have the following regular expression:
^[[][A-Za-z_1-9]+[\]]$
I want to be able to get all the matches of this regular expression in a string. The match should be of the form [Whatever]. Inside the braces, there could also be an _ or numeric characters. So I wrote the following code:
private const String REGEX = #"^[[][A-Za-z_1-9]+[\]]$";
static void Main(string[] args)
{
String expression = "([ColumnName] * 500) / ([AnotherColumn] - 50)";
MatchCollection matches = Regex.Matches(expression, REGEX);
foreach (Match match in matches)
{
Console.WriteLine(match.Value);
}
Console.ReadLine();
}
But unfortunately, matches is always having a count of zero. Apparently, the regular expression is checking whether the whole String is a match and not getting the matches out of the string. I'm not sure whether the regular expression is wrong or the way I'm using Regex.Matches() is incorrect.
Any thoughts?
You need to remove the start/end of string anchors (^ and $) from your pattern, since the matches you are looking for are not actually at the start and end of the string. You can also just use \[ and \] instead of [[] and [\]]:
private const String REGEX = #"\[[A-Za-z_1-9]+\]";
Should do the trick.
You're anchoring your regex to the beginning and end of the string so of course it won't match anything.
Removing the anchors (^ for beginning and $ for end) works fine:
[[][A-Za-z_1-9]+[\]]
It returns, as you would hopefully expect:
[ColumnName]
[AnotherColumn]
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