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I convert a HTML code to plain text.But there are many extra returns and spaces.How to remove them?

Shisoft
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  • it sounds obvious, but if replacing spaces and CRLFs doesn't beautify your HTML enough, you may consider using an [HTML formatter](http://stackoverflow.com/a/15120971/382515) – Ivan Ferrer Villa Sep 30 '16 at 15:36

4 Answers4

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string new_string = Regex.Replace(orig_string, @"\s", "") will remove all whitespace

string new_string = Regex.Replace(orig_string, @"\s+", " ") will just collapse multiple whitespaces into one

Daniel DiPaolo
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16

I'm assuming that you want to

  • find two or more consecutive spaces and replace them with a single space, and
  • find two or more consecutive newlines and replace them with a single newline.

If that's correct, then you could use

resultString = Regex.Replace(subjectString, @"( |\r?\n)\1+", "$1");

This keeps the original "type" of whitespace intact and also preserves Windows line endings correctly. If you also want to "condense" multiple tabs into one, use

resultString = Regex.Replace(subjectString, @"( |\t|\r?\n)\1+", "$1");

To condense a string of newlines and spaces (any number of each) into a single newline, use

resultString = Regex.Replace(subjectString, @"(?:(?:\r?\n)+ +){2,}", @"\n");
Tim Pietzcker
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  • +1 for maintaining new lines and only collapsing duplicates of the same type – John McDonald Feb 11 '11 at 21:44
  • good,but there is on more suitation cannot solve.like `\n \n \n \n \n \n \n \n \n \n` returns mixed with spaces – Shisoft Feb 12 '11 at 09:50
  • And what do you want the result to be in that case? What if you have something like `\n\n \n\n \n\n` or `\n  \n  \n  \n` or `\n \n\n \n \n\n \n \n\n` etc.? – Tim Pietzcker Feb 12 '11 at 10:22
  • @Tim Pietzcker I want sequent spaces to " " sequent returns to "\n",and then returns with spaces like `\n\n \n\n \n\n \n` to "\n".ps:there are more than one space between "\n"s – Shisoft Feb 12 '11 at 10:33
  • I think I can do it by replacing the string twice.First jsut like the answer.Next,replace `\n \n \n \n \n \n \n \n \n \n`. – Shisoft Feb 12 '11 at 10:45
  • I have added another regex for this case; this would have to be applied before or after the other regex. – Tim Pietzcker Feb 12 '11 at 13:03
  • (.NET) If you want to keep the carriage returns which are included with \s, use [ \t] instead of \s. //remove multiple carriage returns txt = Regex.Replace(txt, @"( |\r?\n)\1+", "$1"); // remove duplicate blank spaces or multiple tabs txt = Regex.Replace(txt, @"[ \t]+", " "); // remove blank lines or lines consisting of spaces and tabs txt = Regex.Replace(txt, @"^[ \t]+$[\r\n]*", "", RegexOptions.Multiline).Trim(); – Allen Jan 29 '15 at 15:52
  • @TimPietzcker What would be the change in this regex, `Regex.Replace(subjectString, @"( |\r?\n)\1+", "$1");` If I want to remove the `\r\n` as well – Ammar Khan Mar 27 '17 at 09:10
  • @AmmarKhan: Would you also want to remove spaces? If yes, just replace the match with an empty string. If not, it's complicated, and an answer wouldn't fit inside a comment. – Tim Pietzcker Mar 27 '17 at 20:46
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I used a lot of algorithm for that. Every loop was good but this was clear and absolute.

//define what you want to remove as char

char tb = (char)9; //Tab char ascii code
spc = (char)32;    //space char ascii code
nwln = (char)10;   //New line char ascii char

yourstring.Replace(tb,"");
yourstring.Replace(spc,"");
yourstring.Replace(nwln,"");

//by defining chars, result was better.
ithnegique
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You can use Trim() to remove the spaces and returns. In HTML the spaces is not important so you can omit them by using the Trim() method in System.String class.

Mohammad M. Ramezanpour
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    I think trim can just remove start space and end space – Shisoft Feb 11 '11 at 20:14
  • In fact, only leading and trailing characters are supported: http://msdn.microsoft.com/en-us/library/system.string.trim.aspx. +1 for suggesting an alternative though, maybe try to expand idea on this for the OP and give a regexless solution? – Grant Thomas Feb 11 '11 at 20:20
  • You can remove white spaces and also other chars you may want to remove. If you want to remove returns, I think the best way is Use this: "Your Html".Trim('\n') – Mohammad M. Ramezanpour Feb 11 '11 at 20:23
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    The point is, it only removes them from the **beginning** and **end** of the string. The OP is trying to collapse whitespace throughout the string. `Trim` may be useful, but it won't do the whole job. – Alan Moore Feb 12 '11 at 04:11