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remove text in between delimiters in a string - regex

I have been trying real hard understanding regular expression, Is there any way I can replace character(s) that is between two regex/ For example I have
string datax = "a4726e1e-babb-4898-a5d5-e29d2bc40028;POPULATE DATA AØ99c1d133-15f5-4ef5-bc59- d9ed673b70c6;POPULATE DATA BØ";
how to remove string between regex ";" and "Ø" ???
i try to use code like this :
string xresult = Regex.Replace(datax, #"(?<=;)(\w+?)(?=Ø)", "");
But not working.
please corrected and give me solutions...
thanks...
i want the result like this sir :
string datax = "a4726e1e-babb-4898-a5d5-e29d2bc40028;Ø99c1d133-15f5-4ef5-bc59-d9ed673b70c6;Ø";

I think you need to understand regex a little better and how the replace function works. with regex you're defining capture groups, and with the replace function you want to replace those groups.
how to remove string between regex ";" and "Ø" ???
Step 1: First find ";",then capture all characters up to and including "Ø".
That's (;.*?Ø)
( New Capture Group
; Match ";"
. Match Anything
* Zero or more times
? Be Lazy
Ø Match "Ø"
) End Capture
Step 2: Replace each group with ";Ø"
public static string Replace(string input, string pattern, string
replacement)
So you need to put back the ";Ø" you removed from the original capture.
static void Test2()
{
foreach (string item in SO2588078())
{
Console.WriteLine(item);
}
string input = "a4726e1e-babb-4898-a5d5-e29d2bc40028;POPULATE DATA AØ99c1d133-15f5-4ef5-bc59- d9ed673b70c6;POPULATE DATA BØ";
string regex = "(;.*?Ø)";
string output = Regex.Replace(input, regex, ";Ø");
if (output == string.Join(";Ø", SO2588078()) + ";Ø")
{
Console.WriteLine("TRUE");
}
}
An alternative would be to parse the string without regex. It's a simple format and this gives you more control over the process so you can see what's happening, why it's gone wrong and why it gives the results it does. Since you can step through it.
private static IEnumerable<string> SO2588078()
{
string datax = "a4726e1e-babb-4898-a5d5-e29d2bc40028;POPULATE DATA AØ99c1d133-15f5-4ef5-bc59- d9ed673b70c6;POPULATE DATA BØ";
string temp = datax;
while (!string.IsNullOrEmpty(temp))
{
int index1 = temp.IndexOf(';');
if (index1 > -1)
{
string guid = temp.Remove(index1);
yield return guid;
int index2 = temp.IndexOf('Ø');
if (index2 > -1)
{
temp = temp.Substring(index2 + 1);
}
else
{
temp = null;
}
}
else
{
temp = null;
}
}
}

How to remove a duplicate set of characters in a string

For example a string contains the following (the string is variable):
http://www.google.comhttp://www.google.com
What would be the most efficient way of removing the duplicate url here - e.g. output would be:
http://www.google.com

I assume that input contains only urls.
string input = "http://www.google.comhttp://www.google.com";
// this will get you distinct URLs but without "http://" at the beginning
IEnumerable<string> distinctAddresses = input
.Split(new[] {"http://"}, StringSplitOptions.RemoveEmptyEntries)
.Distinct();
StringBuilder output = new StringBuilder();
foreach (string distinctAddress in distinctAddresses)
{
// when building the output, insert "http://" before each address so
// that it resembles the original
output.Append("http://");
output.Append(distinctAddress);
}
Console.WriteLine(output);

Efficiency has various definitions: code size, total execution time, CPU usage, space usage, time to write the code, etc. If you want to be "efficient", you should know which one of these you're trying for.
I'd do something like this:
string url = "http://www.google.comhttp://www.google.com";
if (url.Length % 2 == 0)
{
string secondHalf = url.Substring(url.Length / 2);
if (url.StartsWith(secondHalf))
{
url = secondHalf;
}
}
Depending on the kinds of duplicates you need to remove, this may or may not work for you.

collect strings into list and use distinct, if your string has http address you can apply regex http:.+?(?=((http:)|($)) with RegexOptions.SingleLine
var distinctList = list.Distinct(StringComparer.CurrentCultureIgnoreCase).ToList();

Given you don't know the length of the string, you don't know if something is double and you don't know what is double:
string yourprimarystring = "http://www.google.comhttp://www.google.com";
int firstCharacter;
string temp;
for(int i = 0; i <= yourprimarystring.length; i++)
{
for(int j = 0; j <= yourprimarystring.length; j++)
{
string search = yourprimarystring.substring(i,j);
firstCharacter = yourprimaryString.IndexOf(search);
if(firstCharacter != -1)
{
temp = yourprimarystring.substring(0,firstCharacter) + yourprimarystring.substring(firstCharacter + j - i,yourprimarystring.length)
yourprimarystring = temp;
}
}
This itterates through all your elements, takes all out from first to last letter and searches for them like this:
ABCDA - searches for A finds A exludes A, thats the problem, you need to specify how long the duplication needs to be if you want to make it variable, but maybe my code helps you.

Finding the number of occurences strings in a specific format occur in a given text

I have a large string, where there can be specific words (text followed by a single colon, like "test:") occurring more than once. For example, like this:
word:
TEST:
word:
TEST:
TEST: // random text
"word" occurs twice and "TEST" occurs thrice, but the amount can be variable. Also, these words don't have to be in the same order and there can be more text in the same line as the word (as shown in the last example of "TEST"). What I need to do is append the occurrence number to each word, for example the output string needs to be this:
word_ONE:
TEST_ONE:
word_TWO:
TEST_TWO:
TEST_THREE: // random text
The RegEx for getting these words which I've written is ^\b[A-Za-z0-9_]{4,}\b:. However, I don't know how to accomplish the above in a fast way. Any ideas?

Regex is perfect for this job - using Replace with a match evaluator:
This example is not tested nor compiled:
public class Fix
{
public static String Execute(string largeText)
{
return Regex.Replace(largeText, "^(\w{4,}):", new Fix().Evaluator);
}
private Dictionary<String, int> counters = new Dictionary<String, int>();
private static String[] numbers = {"ONE", "TWO", "THREE",...};
public String Evaluator(Match m)
{
String word = m.Groups[1].Value;
int count;
if (!counters.TryGetValue(word, out count))
count = 0;
count++;
counters[word] = count;
return word + "_" + numbers[count-1] + ":";
}
}
This should return what you requested when calling:
result = Fix.Execute(largeText);

i think you can do this with Regax.Replace(string, string, MatchEvaluator) and a dictionary.
Dictionary<string, int> wordCount=new Dictionary<string,int>();
string AppendIndex(Match m)
{
string matchedString = m.ToString();
if(wordCount.Contains(matchedString))
wordCount[matchedString]=wordCount[matchedString]+1;
else
wordCount.Add(matchedString, 1);
return matchedString + "_"+ wordCount.ToString();// in the format: word_1, word_2
}
string inputText = "....";
string regexText = #"";
static void Main()
{
string text = "....";
string result = Regex.Replace(text, #"^\b[A-Za-z0-9_]{4,}\b:",
new MatchEvaluator(AppendIndex));
}
see this:
http://msdn.microsoft.com/en-US/library/cft8645c(v=VS.80).aspx

If I understand you correctly, regex is not necessary here.
You can split your large string by the ':' character. Maybe you also need to read line by line (split by '\n'). After that you just create a dictionary (IDictionary<string, int>), which counts the occurrences of certain words. Every time you find word x, you increase the counter in the dictionary.
EDIT
Read your file line by line OR split the string by '\n'
Check if your delimiter is present. Either by splitting by ':' OR using regex.
Get the first item from the split array OR the first match of your regex.
Use a dictionary to count your occurrences.
if (dictionary.Contains(key)) dictionary[key]++;
else dictionary.Add(key, 1);
If you need words instead of numbers, then create another dictionary for these. So that dictionary[key] equals one if key equals 1. Mabye there is another solution for that.

Look at this example (I know it's not perfect and not so nice)
lets leave the exact argument for the Split function, I think it can help
static void Main(string[] args)
{
string a = "word:word:test:-1+234=567:test:test:";
string[] tks = a.Split(':');
Regex re = new Regex(#"^\b[A-Za-z0-9_]{4,}\b");
var res = from x in tks
where re.Matches(x).Count > 0
select x + DecodeNO(tks.Count(y=>y.Equals(x)));
foreach (var item in res)
{
Console.WriteLine(item);
}
Console.ReadLine();
}
private static string DecodeNO(int n)
{
switch (n)
{
case 1:
return "_one";
case 2:
return "_two";
case 3:
return "_three";
}
return "";
}

What is the best way to parse this string in C#?

I have a string that I am reading from another system. It's basically a long string that represents a list of key value pairs that are separated by a space in between. It looks like this:
key:value[space]key:value[space]key:value[space]
So I wrote this code to parse it:
string myString = ReadinString();
string[] tokens = myString.split(' ');
foreach (string token in tokens) {
string key = token.split(':')[0];
string value = token.split(':')[1];
. . . .
}
The issue now is that some of the values have spaces in them so my "simplistic" split at the top no longer works. I wanted to see how I could still parse out the list of key value pairs (given space as a separator character) now that I know there also could be spaces in the value field as split doesn't seem like it's going to be able to work anymore.
NOTE: I now confirmed that KEYs will NOT have spaces in them so I only have to worry about the values. Apologies for the confusion.

Use this regular expression:
\w+:[\w\s]+(?![\w+:])
I tested it on
test:testvalue test2:test value test3:testvalue3
It returns three matches:
test:testvalue
test2:test value
test3:testvalue3
You can change \w to any character set that can occur in your input.
Code for testing this:
var regex = new Regex(#"\w+:[\w\s]+(?![\w+:])");
var test = "test:testvalue test2:test value test3:testvalue3";
foreach (Match match in regex.Matches(test))
{
var key = match.Value.Split(':')[0];
var value = match.Value.Split(':')[1];
Console.WriteLine("{0}:{1}", key, value);
}
Console.ReadLine();
As Wonko the Sane pointed out, this regular expression will fail on values with :. If you predict such situation, use \w+:[\w: ]+?(?![\w+:]) as the regular expression. This will still fail when a colon in value is preceded by space though... I'll think about solution to this.

This cannot work without changing your split from a space to something else such as a "|".
Consider this:
Alfred Bester:Alfred Bester Alfred:Alfred Bester
Is this Key "Alfred Bester" & value Alfred" or Key "Alfred" & value "Bester Alfred"?

string input = "foo:Foobarius Maximus Tiberius Kirk bar:Barforama zap:Zip Brannigan";
foreach (Match match in Regex.Matches(input, #"(\w+):([^:]+)(?![\w+:])"))
{
Console.WriteLine("{0} = {1}",
match.Groups[1].Value,
match.Groups[2].Value
);
}
Gives you:
foo = Foobarius Maximus Tiberius Kirk
bar = Barforama
zap = Zip Brannigan

You could try to Url encode the content between the space (The keys and the values not the : symbol) but this would require that you have control over the Input Method.
Or you could simply use another format (Like XML or JSON), but again you will need control over the Input Format.
If you can't control the input format you could always use a Regular expression and that searches for single spaces where a word plus : follows.
Update (Thanks Jon Grant)
It appears that you can have spaces in the key and the value. If this is the case you will need to seriously rethink your strategy as even Regex won't help.

string input = "key1:value key2:value key3:value";
Dictionary<string, string> dic = input.Split(' ').Select(x => x.Split(':')).ToDictionary(x => x[0], x => x[1]);
The first will produce an array:
"key:value", "key:value"
Then an array of arrays:
{ "key", "value" }, { "key", "value" }
And then a dictionary:
"key" => "value", "key" => "value"
Note, that Dictionary<K,V> doesn't allow duplicated keys, it will raise an exception in such a case. If such a scenario is possible, use ToLookup().

Using a regular expression can solve your problem:
private void DoSplit(string str)
{
str += str.Trim() + " ";
string patterns = #"\w+:([\w+\s*])+[^!\w+:]";
var r = new System.Text.RegularExpressions.Regex(patterns);
var ms = r.Matches(str);
foreach (System.Text.RegularExpressions.Match item in ms)
{
string[] s = item.Value.Split(new char[] { ':' });
//Do something
}
}

This code will do it (given the rules below). It parses the keys and values and returns them in a Dictonary<string, string> data structure. I have added some code at the end that assumes given your example that the last value of the entire string/stream will be appended with a [space]:
private Dictionary<string, string> ParseKeyValues(string input)
{
Dictionary<string, string> items = new Dictionary<string, string>();
string[] parts = input.Split(':');
string key = parts[0];
string value;
int currentIndex = 1;
while (currentIndex < parts.Length-1)
{
int indexOfLastSpace=parts[currentIndex].LastIndexOf(' ');
value = parts[currentIndex].Substring(0, indexOfLastSpace);
items.Add(key, value);
key = parts[currentIndex].Substring(indexOfLastSpace + 1);
currentIndex++;
}
value = parts[parts.Length - 1].Substring(0,parts[parts.Length - 1].Length-1);
items.Add(key, parts[parts.Length-1]);
return items;
}
Note: this algorithm assumes the following rules:
No spaces in the values
No colons in the keys
No colons in the values

Without any Regex nor string concat, and as an enumerable (it supposes keys don't have spaces, but values can):
public static IEnumerable<KeyValuePair<string, string>> Split(string text)
{
if (text == null)
yield break;
int keyStart = 0;
int keyEnd = -1;
int lastSpace = -1;
for(int i = 0; i < text.Length; i++)
{
if (text[i] == ' ')
{
lastSpace = i;
continue;
}
if (text[i] == ':')
{
if (lastSpace >= 0)
{
yield return new KeyValuePair<string, string>(text.Substring(keyStart, keyEnd - keyStart), text.Substring(keyEnd + 1, lastSpace - keyEnd - 1));
keyStart = lastSpace + 1;
}
keyEnd = i;
continue;
}
}
if (keyEnd >= 0)
yield return new KeyValuePair<string, string>(text.Substring(keyStart, keyEnd - keyStart), text.Substring(keyEnd + 1));
}

I guess you could take your method and expand upon it slightly to deal with this stuff...
Kind of pseudocode:
List<string> parsedTokens = new List<String>();
string[] tokens = myString.split(' ');
for(int i = 0; i < tokens.Length; i++)
{
// We need to deal with the special case of the last item,
// or if the following item does not contain a colon.
if(i == tokens.Length - 1 || tokens[i+1].IndexOf(':' > -1)
{
parsedTokens.Add(tokens[i]);
}
else
{
// This bit needs to be refined to deal with values with multiple spaces...
parsedTokens.Add(tokens[i] + " " + tokens[i+1]);
}
}
Another approach would be to split on the colon... That way, your first array item would be the name of the first key, second item would be the value of the first key and then name of the second key (can use LastIndexOf to split it out), and so on. This would obviously get very messy if the values can include colons, or the keys can contain spaces, but in that case you'd be pretty much out of luck...

Removing duplicate substrings within a string in C#

How can I remove duplicate substrings within a string? so for instance if I have a string like smith:rodgers:someone:smith:white then how can I get a new string that has the extra smith removed like smith:rodgers:someone:white. Also I'd like to keep the colons even though they are duplicated.
many thanks

string input = "smith:rodgers:someone:smith:white";
string output = string.Join(":", input.Split(':').Distinct().ToArray());
Of course this code assumes that you're only looking for duplicate "field" values. That won't remove "smithsmith" in the following string:
"smith:rodgers:someone:smithsmith:white"
It would be possible to write an algorithm to do that, but quite difficult to make it efficient...

Something like this:
string withoutDuplicates = String.Join(":", myString.Split(':').Distinct().ToArray());

Assuming the format of that string:
var theString = "smith:rodgers:someone:smith:white";
var subStrings = theString.Split(new char[] { ':' });
var uniqueEntries = new List<string>();
foreach(var item in subStrings)
{
if (!uniqueEntries.Contains(item))
{
uniqueEntries.Add(item);
}
}
var uniquifiedStringBuilder = new StringBuilder();
foreach(var item in uniqueEntries)
{
uniquifiedStringBuilder.AppendFormat("{0}:", item);
}
var uniqueString = uniquifiedStringBuilder.ToString().Substring(0, uniquifiedStringBuilder.Length - 1);
Is rather long-winded but shows the process to get from one to the other.

not sure why you want to keep the duplicate colons. if you are expecting the output to be "smith:rodgers:someone::white" try this code:
public static string RemoveDuplicates(string input)
{
string output = string.Empty;
System.Collections.Specialized.StringCollection unique = new System.Collections.Specialized.StringCollection();
string[] parts = input.Split(':');
foreach (string part in parts)
{
output += ":";
if (!unique.Contains(part))
{
unique.Add(part);
output += part;
}
}
output = output.Substring(1);
return output;
}
ofcourse i've not checked for null input, but i'm sure u'll do it ;)