Remove whitespace in elements in string C#

Question

I have a string which contains multiple items separated by commas :

 string RESULT =  "D_CA,     P_AMOUNT    ,D_SH,D_CU,D_TO,D_GO,D_LE,D_NU,D_CO,D_MU,D_PMU,D_DP,    P_COMMENT      ";

As you can see some elements contain Whitespaces, My object is to remove all the whitespaces, This is my code:

    RESULT.Split(',').ToList().ForEach(p =>
        if (p.Contains(" "))
        {
               RESULT = RESULT.Replace(p, p.Trim());
        }
        });

And this is my result:

"D_CA,P_AMOUNT,D_SH,D_CU,D_TO,D_GO,D_LE,D_NU,D_CO,D_MU,D_PMU,D_DP,P_COMMENT"

it works well, But I ask if there is another more optimized way to get the same result?

Does this answer your question? Remove whitespace from a string in C#? — nalka
– nalka, Commented Jan 10, 2020 at 10:12

Alexander Goldabin · Accepted Answer · 2020-01-10 09:43:45Z

8

Isn't what you looking for?

var noWhiteSpaces = RESULT.Replace(" ", string.Empty);

answered Jan 10, 2020 at 9:43

Alexander Goldabin

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1 Comment

Martin Zikmund Over a year ago

This works with spaces only, not general whitespace characters.

Anu Viswan · Accepted Answer · 2020-01-10 09:52:46Z

8

I suppose you need the string with whitespaces removed. You could use String.Replace()

RESULT = RESULT.Replace(" ",string.Empty);

Alternatively, you could also use Regex for replace,

RESULT = Regex.Replace(RESULT,@"\s",string.Empty);

The regex approach would ensure replacement of all whitespace characters including tab,space etc

edited Jan 10, 2020 at 9:52

answered Jan 10, 2020 at 9:43

Anu Viswan

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Comments

Martin Zikmund · Accepted Answer · 2020-01-10 16:20:00Z

7

See the answer by Pavel Anikhouski, which checks the performance of all suggested solutions and actually shows that the simplified LINQ solution does not help performance too much - good to know :-) .

Simpler solution with LINQ:

string.Join(string.Empty, input.Where(c=>!char.IsWhiteSpace(c)));

First we filter away all whitespace characters and then we join them into a string. This has only one string allocation (to create the resulting string) and handles all kinds of whitespace characters, not only spaces.

Original answer

Use a StringBuilder to build up the resulting string and then go through the input string with a foreach, always checking char.IsWhiteSpace(character). In case the character is not whitespace, append it in the StringBuilder by calling Append(character) method. At the end just return the resulting string by calling ToString() on the StringBuilder.

var builder = new StringBuilder();
foreach(var character in input)
{
   if (!char.IsWhiteSpace(character))
   {
      builder.Append(character);
   }
}
return builder.ToString();

This implementation is more efficient, as it does not produce any string allocations, except for the end result. It just works with the input string and reads it once.

edited Jan 10, 2020 at 16:20

answered Jan 10, 2020 at 9:43

Martin Zikmund

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7 Comments

Cid Over a year ago

Isn't it a bit overkill to use a StringBuilder and loops when one can just Replace() ?

Cid Over a year ago

Regex.Replace(input, @"\s", string.Empty); should do the job

Martin Zikmund Over a year ago

Regex is however slower the first time, as it needs to be parsed. I think that would hinder the performance benefit (although worth a benchmark :-) )

Martin Zikmund Over a year ago

As the OP asked for optimized solution, I suppose the performance is primary concern. But agreed regex and LINQ solutions are more readable than the one I posted originally :-D

Pavel Anikhouski Over a year ago

Actually, regex is 10 times slower, that solution using stringbuilder. Extension method from my answer above is about 30-40% slower, the solution here. That's about performance :)

|

StepUp · Accepted Answer · 2020-01-10 09:48:23Z

5

You can Trim():

var split = RESULT.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
    .Select(s=> s.Trim());

edited Jan 10, 2020 at 9:48

answered Jan 10, 2020 at 9:42

StepUp

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Comments

Pavel Anikhouski · Accepted Answer · 2020-01-29 13:58:07Z

4

You can use the following extension method for that

public static class Ext
{
    public static string RemoveWhitespaces(this string input)
    {
        return new string(input.ToCharArray()
            .Where(c => !char.IsWhiteSpace(c))
            .ToArray());
    }
}

Usage sample

string RESULT = "D_CA,     P_AMOUNT    ,D_SH,D_CU,D_TO,D_GO,D_LE,D_NU,D_CO,D_MU,D_PMU,D_DP,    P_COMMENT      ";
RESULT = RESULT.RemoveWhitespaces();

Char.IsWhiteSpace method indicates all Unicode whitespace characters.

There is a simple benchmark for all proposed solutions below. In terms of performance the usual Replace is fastest method, but it doesn't remove all whitespace characters. The solution with StringBuilder seems most relevant in terms of performance and functionality, it's about 2 times faster than extension above. The Regex and Linq solution are few times slower than other ones

edited Jan 29, 2020 at 13:58

answered Jan 10, 2020 at 9:48

Pavel Anikhouski

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3 Comments

Pavel Anikhouski Over a year ago

@MartinZikmund thank you, I've added a string builder result as well

Martin Zikmund Over a year ago

Could you check the LINQ solution too, please :-) ?

Pavel Anikhouski Over a year ago

@MartinZikmund I've added details, Linq solution is expensive as well, but faster than regex

Ignasi93 · Accepted Answer · 2020-01-10 09:45:15Z

3

You can simplify the code like this:

RESULT.Replace(" ", string.Empty).Split(',');

Assuming that you need the elements in an Enumerable. Otherwise just the Replace() should work for you.

answered Jan 10, 2020 at 9:45

Ignasi93

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Comments

Serhii Matvienko · Accepted Answer · 2020-01-12 17:11:46Z

1

I can only to add that you can put the linq into the static method

public static class Utility
{
    public static string RemoveWhitespaces(this string input)
    {
        return string.Join(string.Empty, input.Where(c => !char.IsWhiteSpace(c)));
    }
}

and then use it with any your string:

Console.WriteLine("asdas asdas sa   asdasd232 sd".RemoveWhitespaces());

answered Jan 12, 2020 at 17:11

Serhii Matvienko

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Comments

Jeevitha · Accepted Answer · 2020-01-14 07:34:48Z

-1

RESULT.Replace(" ", string.Empty);

answered Jan 14, 2020 at 7:34

Jeevitha

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Comments

Sorena Gh · Accepted Answer · 2020-01-11 12:40:31Z

-2

You can use .Trim() to make a new string without any whitespaces.

string x = "Hello World";
console.writeline(x.Trim());
//Output : "HelloWorld"

you can check other overloads of string.Trim() here: String.Trim Method

answered Jan 11, 2020 at 12:40

Sorena Gh

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2 Comments

jalsh Over a year ago

The very link you provided clearly states Trim() Removes all leading and trailing white-space characters from the current string. The output of your code is "Hello World".....

Sorena Gh Over a year ago

Try it yourself!

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