RegEx to extract characters in a string - c#

I need to extract a set of characters in of a string. I plan on usng the RegEx.Match method (c#) but I am unclear about the RegEx pattern to use. I want to extract a pattern where it starts with // and ends with ...
Then length needs to be variable inside the matched string but the start and end characters will always be the same. In DOS, I would have done something like the following:
//*...
but I know this is not the correct syntax for RegEx.

Try with pattern
"//.*?\.\.\."
or
"//.*?\.{3}"
Some codes
string data = #"some codes //to double check...
another codes //done...
//to do...";
MatchCollection matches = Regex.Matches(data, #"//(.*?)\.\.\.");
foreach (Match m in matches) {
print(m.Groups[1].Value);
}
results
to double check
done
to do

Related

Find String Between To Identical Control Separators?

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)).

Improve RegEx search

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 "(" ")"
}

How can I capture value from capture function in C#

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.

Pattern Matching c#

Lets say I have a text file with the line below within it. I want to take both values within the quotations by matching between (" and "), so that would be I retreive ABC and DEF and put them in a string list or something, what's the best way of doing this? It's so annoying
If EXAMPLEA("ABC") AND EXAMPLEB("DEF")
Assuming a case where the value between the double quotes can not contain escaped double quotes might work like this:
var text = "If EXAMPLEA(\"ABC\") AND EXAMPLEB(\"DEF\")";
Regex pattern = new Regex("\"[^\"]*\"");
foreach (Match match in pattern.Matches(text))
{
Console.WriteLine(match.Value.Trim('"'));
}
But this is only one of the many ways you could do it and maybe not the smartest way out there. Try something yourself!
Best way...
List<string> matches=Regex.Matches(File.ReadAllText(yourPath),"(?<="")[^""]*(?="")")
.Cast<Match>()
.Select(x=>x.Value)
.ToList();
This pattern should do the trick:
\"([^"]*)\"
string str = "If EXAMPLEA(\"ABC\") AND EXAMPLEB(\"DEF\")";
MatchCollection matched = Regex.Matches(str, #"\""([^\""]*)\""");
foreach (Match match in matched)
{
Console.WriteLine(match.Groups[1].Value);
}
Note that the quotation marks are doubled in the actual code in order to escape them. And the code refers to group [1] to get just the part inside the parentheses.
IEnumerable<string> matches =
from Match match
in Regex.Matches(File.ReadAllText(filepath), #"\""([^\""]*)\""")
select match.Groups[1].Value;
Others already posted some answers, but my takes into account that you just want ABC and DEF in your example, without quotation marks and save it in a IEnumerable<string>.

match first digits before # symbol

How to match all first digits before # in this line
26909578#Sbrntrl_7x06-lilla.avi#356028416#2012-10-24 09:06#0#http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html#[URL=http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html]http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html[/URL]#http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html#http://bitshare.com/?f=dvk9o1oz#http://bitshare.com/delete/dvk9o1oz/4511e6f3612961f961a761adcb7e40a0/Sbrntrl_7x06-lilla.avi.html
Im trying to get this number 26909578
My try
string text = #"26909578#Sbrntrl_7x06-lilla.avi#356028416#2012-10-24 09:06#0#http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html#[URL=http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html]http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html[/URL]#http://bitshare.com/files/dvk9o1oz/Sbrntrl_7x06-lilla.avi.html#http://bitshare.com/?f=dvk9o1oz#http://bitshare.com/delete/dvk9o1oz/4511e6f3612961f961a761adcb7e40a0/Sbrntrl_7x06-lilla.avi.html";
MatchCollection m1 = Regex.Matches(text, #"(.+?)#", RegexOptions.Singleline);
but then its outputs all text
Make it explicit that it has to start at the beginning of the string:
#"^(.+?)#"
Alternatively, if you know that this will always be a number, restrict the possible characters to digits:
#"^\d+"
Alternatively use the function Match instead of Matches. Matches explicitly says, "give me all the matches", while Match will only return the first one.
Or, in a trivial case like this, you might also consider a non-RegEx approach. The IndexOf() method will locate the '#' and you could easily strip off what came before.
I even wrote a sscanf() replacement for C#, which you can see in my article A sscanf() Replacement for .NET.
If you dont want to/dont like to use regex, use a string builder and just loop until you hit the #.
so like this
StringBuilder sb = new StringBuilder();
string yourdata = "yourdata";
int i = 0;
while(yourdata[i]!='#')
{
sb.Append(yourdata[i]);
i++;
}
//when you get to that # your stringbuilder will have the number you want in it so return it with .toString();
string answer = sb.toString();
The entire string (except the final url) is composed of segments that can be matched by (.+?)#, so you will get several matches. Retrieve only the first match from the collection returned by matching .+?(?=#)

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