Develop Reference

Html.Decoded ­ is problematic in string functions

string local= HttpUtility.HtmlDecode(GetLocalizedSupportPhone()).Replace("-", "").Replace(" ", "");
I am getting a string :
"0­12­4 41­481­73"
from the GetLocalizedSupportPhone() method. The Html Decode method returns:
"0-12-4 41-481-73"
I have a list of phone numbers like:- "01244148173", "01244148173", etc which are plain integers without any space character or html character.
Problem scenario:- All i want to do is to get decoded local string ("0-12-4 41-481-73"), replace the ­ as well as " " with empty string character and compare the resultant local string with the list items. If a similar list item exists, then remove that particular list item.
But strangely, the .Replace() method replaces space character with blank string but is unable to replace "-" with empty string.
I am just curious why is it happening? Why ANY OF THE STRING METHODS (like I tried with .split() ) can not detect "-"?

There are different types of hyphens. ­ is a soft hyphen. Specifically the soft hyphen is 173 and the hyphen on your keyboard is 45.
Try this instead.
var r = HttpUtility.HtmlDecode("0­12­4 41­481­73")
.Replace((char)173, ' ')
.Replace(" ", "");
That will replace the soft hyphen with a space and then your second replace will get rid of that.
Another option would be to use a regular expression to remove all non-numeric values.
Regex nonNumeric = new Regex(#"\D");
var r = nonNumeric.Replace(
HttpUtility.HtmlDecode("0­12­4 41­481­73"),
string.Empty);

This might help if you're just looking to strip spaces and soft hypens from a string without having to deal with HTML decoding:
var regex = new Regex(#"\u00ad| ");
var result = regex.Replace(stringWithSoftHyphens, string.Empty);
I tried doing this with Trim((char)173) but it (and methods like Split) do not seem to be able to handle the soft hyphen character like the Regex class can.

C# Replace with regex

I'm new to VB, C#, and am struggling with regex. I think I've got the following code format to replace the regex match with blank space in my file.
EDIT: Per comments this code block has been changed.
var fileContents = System.IO.File.ReadAllText(#"C:\path\to\file.csv");
fileContents = fileContents.Replace(fileContents, #"regex", "");
regex = new Regex(pattern);
regex.Replace(filecontents, "");
System.IO.File.WriteAllText(#"C:\path\to\file.csv", fileContents);
My files are formatted like this:
"1111111","22222222222","Text that may, have a comma, or two","2014-09-01",,,,,,
So far, I have regex finding any string between ," and ", that contains a comma (there are never commas in the first or last cell, so I'm not worried about excluding those two. I'm testing regex in Expresso
(?<=,")([^"]+,[^"]+)(?=",)
I'm just not sure how to isolate that comma as what needs to be replaced. What would be the best way to do this?
SOLVED:
Combined [^"]+ with look behind/ahead:
(?<=,"[^"]+)(,)(?=[^"]+",)
FINAL EDIT:
Here's my final complete solution:
//read file contents
var fileContents = System.IO.File.ReadAllText(#"C:\path\to\file.csv");
//find all commas between double quotes
var regex = new Regex("(?<=,\")([^\"]+,[^\"]+(?=\",)");
//replace all commas with ""
fileContents = regex.Replace(fileContents, m => m.ToString().Replace(",", ""));
//write result back to file
System.IO.File.WriteAllText(#"C:\path\to\file.csv", fileContents);

Figured it out by combining the [^"]+ with the look ahead ?= and look behind ?<= so that it finds strings beginning with ,"[anything that's not double quotes, one or more times] then has a comma, then ends with [anything that's not double quotes, one or more times]",
(?<=,"[^"]+)(,)(?=[^"]+",)

Try to parse out all your columns with this:
Regex regex = new Regex("(?<=\").*?(?=\")");
Then you can just do:
foreach(Match match in regex.Matches(filecontents))
{
fileContents = fileContents.Replace(match.ToString(), match.ToString().Replace(",",string.Empty))
}
Might not be as fast but should work.

I would probably use the overload of Regex.Replace that takes a delegate to return the replaced text.
This is useful when you have a simple regex to identify the pattern but you need to do something less straightforward (complex logic) for the replace.
I find keeping your regexes simple will pay benefits when you're trying to maintain them later.
Note: this is similar to the answer by #Florian, but this replace restricts itself to replacement only in the matched text.
string exp = "(?<=,\")([^\"]+,[^\"]+)(?=\",)";
var regex = new Regex(exp);
string replacedtext = regex.Replace(filecontents, m => m.ToString().Replace(",",""))

What you have there is an irregular language. This is because a comma can mean different things depending upon where it is in the text stream. Strangely Regular Expressions are designed to parse regular languages where a comma would mean the same thing regardless of where it is in the text stream. What you need for an irregular language is a parser. In fact Regular expressions are mostly used for tokenizing strings before they are entered into a parser.
While what you are trying to do can be done using regular expressions it is likely to be very slow. For example you can use the following (which will work even if the comma is the first or last character in the field). However every time it finds a comma it will have to scan backwards and forwards to check if it is between two quotation characters.
(?<=,"[^"]*),(?=[^"]*",)
Note also that their may be a flaw in this approach that you have not yet spotted. I don't know if you have this issue but often in CSV files you can have quotation characters in the middle of fields where there may also be a comma. In these cases applications like MS Excel will typically double the quote up to show that it is not the end of the field. Like this:
"1111111","22222222222","Text that may, have a comma, Quote"" or two","2014-09-01",,,,,,
In this case you are going to be out of luck with a regular expression.
Thankfully the code to deal with CSV files is very simple:
public static IList<string> ParseCSVLine(string csvLine)
{
List<string> result = new List<string>();
StringBuilder buffer = new StringBuilder();
bool inQuotes = false;
char lastChar = '\0';
foreach (char c in csvLine)
{
switch (c)
{
case '"':
if (inQuotes)
{
inQuotes = false;
}
else
{
if (lastChar == '"')
{
buffer.Append('"');
}
inQuotes = true;
}
break;
case ',':
if (inQuotes)
{
buffer.Append(',');
}
else
{
result.Add(buffer.ToString());
buffer.Clear();
}
break;
default:
buffer.Append(c);
break;
}
lastChar = c;
}
result.Add(buffer.ToString());
buffer.Clear();
return result;
}
PS. There are another couple of issues often run into with CSV files which the code I have given doesn't solve. First is what happens if a field has an end of line character in the middle of it? Second is how do you know what character encoding a CSV file is in? The former of these two issues is easy to solve by modifying my code slightly. The second however is near impossible to do without coming to some agreement with the person supplying the file to you.

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 .+?(?=#)

How to get all words of a string in c#?

I have a paragraph in a single string and I'd like to get all the words in that paragraph.
My problem is that I don't want the suffixes words that end with punctuation marks such as (',','.',''','"',';',':','!','?') and /n /t etc.
I also don't want words with 's and 'm such as world's where it should only return world.
In the example
he said. "My dog's bone, toy, are missing!"
the list should be: he said my dog bone toy are missing

Expanding on Shan's answer, I would consider something like this as a starting point:
MatchCollection matches = Regex.Match(input, #"\b[\w']*\b");
Why include the ' character? Because this will prevent words like "we're" from being split into two words. After capturing it, you can manually strip out the suffix yourself (whereas otherwise, you couldn't recognize that re is not a word and ignore it).
So:
static string[] GetWords(string input)
{
MatchCollection matches = Regex.Matches(input, #"\b[\w']*\b");
var words = from m in matches.Cast<Match>()
where !string.IsNullOrEmpty(m.Value)
select TrimSuffix(m.Value);
return words.ToArray();
}
static string TrimSuffix(string word)
{
int apostropheLocation = word.IndexOf('\'');
if (apostropheLocation != -1)
{
word = word.Substring(0, apostropheLocation);
}
return word;
}
Example input:
he said. "My dog's bone, toy, are missing!" What're you doing tonight, by the way?
Example output:
[he, said, My, dog, bone, toy, are, missing, What, you, doing, tonight, by, the, way]
One limitation of this approach is that it will not handle acronyms well; e.g., "Y.M.C.A." would be treated as four words. I think that could also be handled by including . as a character to match in a word and then stripping it out if it's a full stop afterwards (i.e., by checking that it's the only period in the word as well as the last character).

Hope this is helpful for you:
string[] separators = new string[] {",", ".", "!", "\'", " ", "\'s"};
string text = "My dog's bone, toy, are missing!";
foreach (string word in text.Split(separators, StringSplitOptions.RemoveEmptyEntries))
Console.WriteLine(word);

See Regex word boundary expressions, What is the most efficient way to count all of the words in a richtextbox?. Moral of the story is that there are many ways to approach the problem, but regular expressions are probably the way to go for simplicity.

split on whitespace, trim anything that isn't a letter on the resulting strings.

Here's a looping replace method... not fast, but a way to solve it...
string result = "string to cut ' stuff. ! out of";
".',!#".ToCharArray().ToList().ForEach(a => result = result.Replace(a.ToString(),""));
This assumes you want to place it back in the original string, not a new string or a list.

How do i strip special characters from the end of a string?

I need to strip unknown characters from the end of a string returned from an SQL database. I also need to log when a special character occurs in the string.
What's the best way to do this?

You can use the Trim() method to trim blanks or specific characters from the end of a string. If you need to trim a certain number of characters you can use the Substring() method. You can use Regexs (System.Text.RegularExpressions namespace) to match patterns in a string and detect when they occur. See MSDN for more info.
If you need more help you'll need to provide a bit more info on what exactly you're trying to do.

First define what are unknown characters (chars other than 0-9, a to z and A to Z ?) and put them in an array
Loop trough the characters of a string and check if the char occurs, if so remove.
you can also to a String.Replace with as param the unknown char, and replaceparam ''.

Since you've specified that the legal characters are only alphanumeric, you could do something like this:
Match m = Regex.Match(original, "^([0-9A-Za-z]*)(.*)$");
string good = m.Groups[1].Value;
string bad = m.Groups[2].Value;
if (bad.Length > 0)
{
// log bad characters
}
Console.WriteLine(good);

Your definition of the problem is not precise yet this is a fast trick to do so:
string input;
...
var trimed = input.TrimEnd(new[] {'#','$',...} /* array of unwanted characters */);
if(trimed != input)
myLogger.Log(input.Replace(trimed, ""));

check out the Regex.Replace methods...there are lots of overloads. You can use the Match methods for the logging to identify all matches.
String badString = "HELLO WORLD!!!!";
Regex regex = new Regex("!{1,}$" );
String newString = regex.Replace(badString, String.Empty);