Develop Reference

Removing special characters from a string with RegEx

Am reading a text file that contains words, numbers and special characters, I want to remove certain special characters like: [](),'
I have this code but it is not working !
using (var reader = new StreamReader ("C://Users//HP//Documents//result2.txt")) {
string line = reader.ReadToEnd ();
Regex rgx = new Regex ("[^[]()',]");
string res = rgx.Replace (line, "");
Message1.text = res;
}
what am I missing, thanks

Some of the characters in your Regex, specifically [ ] ( ) ^, hold special meaning in Regex and in order to use them literally they must be escaped.
Use the following properly escaped Regex:
Regex rgx = new Regex (#"[\^\[\]\(\)',]");
Note that it is necessary to use the # verbatim string, because we don't want to escape these characters from the string, only from the Regex.
Alternatively, double escape the backslashes:
Regex rgx = new Regex ("[\\^\\[\\]\\(\\)',]");
But that's less readable in this case.

You could skip Regex and just maintain a list of characters you want to remove and then replace the old fashioned way:
string[] specialCharsToRemove = new [] { "[", "]", "(", ")", "'", "," };
using (var reader = new StreamReader ("C://Users//HP//Documents//result2.txt"))
{
string line = reader.ReadToEnd();
foreach(string s in specialCharsToRemove)
{
line = line.Replace(s, string.Empty);
}
Message1.text = res;
}
Ideally this would be in its own method, something like this:
private static string RemoveCharacters(string input, string[] specialCharactersToRemove)
{
foreach(string s in specialCharactersToRemove)
{
input = input.Replace(s, string.Empty);
}
return input;
}
I made a fiddle here

Replace them one at a time with String.Replace:
using (var reader = new StreamReader ("C://Users//HP//Documents//result2.txt"))
{
string line = reader.ReadToEnd ();
string res = line.Replace(line, "[", "");
res = res.Replace(line, "]", "");
res = res.Replace(line, "(", "");
res = res.Replace(line, ")", "");
res = res.Replace(line, "'", "");
res = res.Replace(line, ",", "");
Message1.text = res;
}

I agree with avoiding regex for this, but I would not use string.Replace multiple times, either.
Consider implementing a Replace or Remove method that accepts an array of characters to replace, and scan the input string only once. For example:
var builder = new StringBuilder();
foreach (char ch in input)
{
if (!chars.Contains(ch))
{
builder.Append(ch):
}
}
return builder.ToString();

how to delete specify string in C#

When i program,i want to delete a specify string in a long string.
For example:
The source string is:
abcdffff<fdfs>adbcccc
abcdffff<fdferfefs>adbcccc
abcdffff<fdffefes>adbcccc
abcdffff<fdffefefs>adbcccc
The i want to delete the string like <fdfs>
The result should be:
abcdffffadbcccc
abcdffffadbcccc
abcdffffadbcccc
abcdffffadbcccc
How could i do?
This is my code:
public string formatMailMessageBody(string herf,string notifyinfo)
{
StringBuilder sb = new StringBuilder();
sb.Append(notifyinfo.Replace("〈%〉", "") + "<br><br>");
sb.Append("单击下面的链接查看您当前任务：<br>");
sb.Append("<a href='" + herf + "'><b>" + herf + "</b></a>");
string s = sb.ToString();
return sb.ToString();
}
Is it right?

Note that the following code is applicable only if the string you want to delete has this format <...> (no other pairs of <> inside):
var output = Regex.Replace(input, #"\<[^>]*\>", "");
The Regex class is located in the namespace System.Text.RegularExpressions.

Remove HTML tags from string including &nbsp in C#

How can I remove all the HTML tags including &nbsp using regex in C#. My string looks like
"<div>hello</div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div> </div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div>"

If you can't use an HTML parser oriented solution to filter out the tags, here's a simple regex for it.
string noHTML = Regex.Replace(inputHTML, #"<[^>]+>| ", "").Trim();
You should ideally make another pass through a regex filter that takes care of multiple spaces as
string noHTMLNormalised = Regex.Replace(noHTML, #"\s{2,}", " ");

I took #Ravi Thapliyal's code and made a method: It is simple and might not clean everything, but so far it is doing what I need it to do.
public static string ScrubHtml(string value) {
var step1 = Regex.Replace(value, #"<[^>]+>| ", "").Trim();
var step2 = Regex.Replace(step1, #"\s{2,}", " ");
return step2;
}

I've been using this function for a while. Removes pretty much any messy html you can throw at it and leaves the text intact.
private static readonly Regex _tags_ = new Regex(#"<[^>]+?>", RegexOptions.Multiline | RegexOptions.Compiled);
//add characters that are should not be removed to this regex
private static readonly Regex _notOkCharacter_ = new Regex(#"[^\w;&##.:/\\?=|%!() -]", RegexOptions.Compiled);
public static String UnHtml(String html)
{
html = HttpUtility.UrlDecode(html);
html = HttpUtility.HtmlDecode(html);
html = RemoveTag(html, "<!--", "-->");
html = RemoveTag(html, "<script", "</script>");
html = RemoveTag(html, "<style", "</style>");
//replace matches of these regexes with space
html = _tags_.Replace(html, " ");
html = _notOkCharacter_.Replace(html, " ");
html = SingleSpacedTrim(html);
return html;
}
private static String RemoveTag(String html, String startTag, String endTag)
{
Boolean bAgain;
do
{
bAgain = false;
Int32 startTagPos = html.IndexOf(startTag, 0, StringComparison.CurrentCultureIgnoreCase);
if (startTagPos < 0)
continue;
Int32 endTagPos = html.IndexOf(endTag, startTagPos + 1, StringComparison.CurrentCultureIgnoreCase);
if (endTagPos <= startTagPos)
continue;
html = html.Remove(startTagPos, endTagPos - startTagPos + endTag.Length);
bAgain = true;
} while (bAgain);
return html;
}
private static String SingleSpacedTrim(String inString)
{
StringBuilder sb = new StringBuilder();
Boolean inBlanks = false;
foreach (Char c in inString)
{
switch (c)
{
case '\r':
case '\n':
case '\t':
case ' ':
if (!inBlanks)
{
inBlanks = true;
sb.Append(' ');
}
continue;
default:
inBlanks = false;
sb.Append(c);
break;
}
}
return sb.ToString().Trim();
}

var noHtml = Regex.Replace(inputHTML, #"<[^>]*(>|$)| |‌|»|«", string.Empty).Trim();

I have used the #RaviThapliyal & #Don Rolling's code but made a little modification. Since we are replacing the &nbsp with empty string but instead &nbsp should be replaced with space, so added an additional step. It worked for me like a charm.
public static string FormatString(string value) {
var step1 = Regex.Replace(value, #"<[^>]+>", "").Trim();
var step2 = Regex.Replace(step1, #" ", " ");
var step3 = Regex.Replace(step2, #"\s{2,}", " ");
return step3;
}
Used &nbps without semicolon because it was getting formatted by the Stack Overflow.

this:
(<.+?> | )
will match any tag or
string regex = #"(<.+?>| )";
var x = Regex.Replace(originalString, regex, "").Trim();
then x = hello

Sanitizing an Html document involves a lot of tricky things. This package maybe of help:
https://github.com/mganss/HtmlSanitizer

HTML is in its basic form just XML. You could Parse your text in an XmlDocument object, and on the root element call InnerText to extract the text. This will strip all HTML tages in any form and also deal with special characters like < all in one go.

i'm using this syntax for remove html tags with
SessionTitle:result[i].sessionTitle.replace(/<[^>]+>|&**nbsp**;/g, '')
--Remove(*) **nbsp**

(<([^>]+)>| )
You can test it here:
https://regex101.com/r/kB0rQ4/1

C# replace part of string but only exact matches possible?

I have a string beginString = "apple|fruitsapple|turnip";
What I want to do is replace just apple with mango, not fruitsapple.
string fixedString = beginString.Replace("apple","mango"); This doesn't work because it replaces both apple and fruitsapple.
Any ideas?

beginString = "|" + beginString + "|";
fixedString = beginString.Replace("|apple|","|mango|");

This cannot be done in the way you have said since it will consider the entire string to be a string. You can do the split by | as you have used or else have the strings in a list and use equals and then replace it.
String[] words = beginString.Split("|");
now do the replace on words. works for any scenario.

The variation on other answers in LINQ style:
string fixedString = string.Join("|",
beginString
.Split('|')
.Select(s => s != "apple" ? s : "mango"));

Closest I can get. Was gonna suggest regular expression, but that won't always work as you want. You have to split the string first and then remake it.
string searchString = "apple";
string newString = "mango";
string beginString = "apple|fruitsapple|turnip";
string[] array = beginString.Split('|');
foreach (var item in array)
{
if (item == searchString)
item.Replace(searchString, newString);
}
string recreated = "";
new List<string>(array).ForEach(e => recreated += e + "|");
recreated.TrimEnd('|');

string newstr = Regex.Replace("apple|fruitsapple|turnip", #"\bapple\b", "mango");

How to trim whitespace between characters

How to remove whitespaces between characters in c#?
Trim() can be used to remove the empty spaces at the beginning of the string as well as at the end. For example " C Sharp ".Trim() results "C Sharp".
But how to make the string into CSharp? We can remove the space using a for or a for each loop along with a temporary variable. But is there any built in method in C#(.Net framework 3.5) to do this like Trim()?

You could use String.Replace method
string str = "C Sharp";
str = str.Replace(" ", "");
or if you want to remove all whitespace characters (space, tabs, line breaks...)
string str = "C Sharp";
str = Regex.Replace(str, #"\s", "");

If you want to keep one space between every word. You can do it this way as well:
string.Join(" ", inputText.Split(new char[0], StringSplitOptions.RemoveEmptyEntries).ToList().Select(x => x.Trim()));

Use String.Replace to replace all white space with nothing.
eg
string newString = myString.Replace(" ", "");

if you want to remove all spaces in one word:
input.Trim().Replace(" ","")
And If you want to remove extra spaces in the sentence, you should use below:
input.Trim().Replace(" +","")
the regex " +", would check if there is one ore more following space characters in the text and replace them with one space.

If you want to keep one space between every word. this should do it..
public static string TrimSpacesBetweenString(string s)
{
var mystring =s.RemoveTandNs().Split(new string[] {" "}, StringSplitOptions.None);
string result = string.Empty;
foreach (var mstr in mystring)
{
var ss = mstr.Trim();
if (!string.IsNullOrEmpty(ss))
{
result = result + ss+" ";
}
}
return result.Trim();
}
it will remove the string in between the string
so if the input is
var s ="c sharp";
result will be "c sharp";

//Remove spaces from a string just using substring method and a for loop
static void Main(string[] args)
{
string businessName;
string newBusinessName = "";
int i;
Write("Enter a business name >>> ");
businessName = ReadLine();
for(i = 0; i < businessName.Length; i++)
{
if (businessName.Substring(i, 1) != " ")
{
newBusinessName += businessName.Substring(i, 1);
}
}
WriteLine("A cool web site name could be www.{0}.com", newBusinessName);
}

var str=" c sharp "; str = str.Trim();
str = Regex.Replace(str, #"\s+", " "); ///"c sharp"

string myString = "C Sharp".Replace(" ", "");

I found this method great for doing things like building a class that utilizes a calculated property to take lets say a "productName" and stripping the whitespace out to create a URL that will equal an image that uses the productname with no spaces. For instance:
namespace XXX.Models
{
public class Product
{
public int ProductID { get; set; }
public string ProductName { get; set; }
public string ProductDescription { get; set; }
public string ProductImage
{
get { return ProductName.Replace(" ", string.Empty) + ".jpg"; }
}
}
}
So in this answer I have used a very similar method as w69rdy, but used it in an example, plus I used string.Empty instead of "". And although after .Net 2.0 there is no difference, I find it much easier to read and understand for others who might need to read my code. I also prefer this because I sometimes get lost in all the quotes I might have in a code block.