How to overwrite a string with another string?

Question

How can I overwrite a string ? Example:

string text = "abcdefghijklmnopqrstuvwxyz".OverwriteWith("hello world", 3);
// text == "abchello worldopqrstuvwxyz"

Of course this method doesn't exist. But

Is there something build in in .NET Framework ?
If not, how can I efficiently write a string into another string ?

Soner Gönül · Answer 1 · 2018-01-29T06:27:29.330

5

You just need to use String.Remove and String.Insert method like;

string text = "abcdefghijklmnopqrstuvwxyz";
if(text.Length > "hello world".Length + 3)
{
   text = text.Remove(3, "hello world".Length).Insert(3, "hello world");
   Console.WriteLine(text);
}

Output will be;

abchello worldopqrstuvwxyz

Here a DEMO.

Remember, strings are immutable types in .NET. You can't change them. Even if you think you change them, you actually create a new string objects.

If you want to work with mutable strings, take a look at StringBuilder class.

This class represents a string-like object whose value is a mutable sequence of characters. The value is said to be mutable because it can be modified once it has been created by appending, removing, replacing, or inserting characters.

edited Jan 29 '18 at 06:27

answered Aug 20 '13 at 07:12

Soner Gönül

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Make sure you test first if this string is long enough. If 3 + 11 is bigger than the length of the string, you'll get an ArgumentOutOfRangeException according MSDN: http://msdn.microsoft.com/en-us/library/d8d7z2kk.aspx – Ben Van Hees Aug 20 '13 at 07:22
1

@BenVanHees In OP case this is not necessary but added it. Thanks. – Soner Gönül Aug 20 '13 at 07:42
Thanks for stealing part of my answer without credit @SonerGönül :P – Gusdor Aug 22 '13 at 07:15
1

@Gusdor Do you think before your answer, I wasn't aware of the terms called `immutable`? Nice thought... – Soner Gönül Aug 22 '13 at 07:25
@SonerGönül I am questioning your integrity, not your knowledge. We communicated the same detail in the same order and same format with only a 3 word difference. Even disregarding the flagrant plagiarism, repetition of the information is redundant. Tell me, what prompted the edits? – Gusdor Aug 22 '13 at 07:41

score 5 · Answer 2 · answered Aug 20 '13 at 07:13

5

Short answer, you cannot. Strings are an immutable type. This means that once they are created, they cannot be modified.

If you want to manipulated strings in memory, the c++ way, you should use a StringBuilder.

answered Aug 20 '13 at 07:13

Gusdor

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score 2 · Answer 3 · edited May 23 '17 at 12:05

2

You can Try this Solution this may help you..

  var theString = "ABCDEFGHIJ";
  var aStringBuilder = new StringBuilder(theString);
  aStringBuilder.Remove(3, 2);  //Used to Remove the 
  aStringBuilder.Replace();  //Write the Required Function in the Replace
  theString = aStringBuilder.ToString();

Reference : Click Here!!

edited May 23 '17 at 12:05

Community

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answered Aug 20 '13 at 07:18

coolprarun

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score 1 · Answer 4 · answered Aug 20 '13 at 07:52

What you want is an extension method:

static class StringEx
{
    public static string OverwriteWith(this string str, string value, int index)
    {
        if (index + value.Length < str.Length)
        {
            // Replace substring
            return str.Remove(index) + value + str.Substring(index + value.Length);
        }
        else if (str.Length == index)
        {
            // Append
            return str + value;
        }
        else
        {
            // Remove ending part + append
            return str.Remove(index) + value;
        }
    }
}

// abchello worldopqrstuvwxyz
string text = "abcdefghijklmnopqrstuvwxyz".OverwriteWith("hello world", 3);
// abchello world
string text2 = "abcd".OverwriteWith("hello world", 3);
// abchello world
string text3 = "abc".OverwriteWith("hello world", 3);
// hello world
string text4 = "abc".OverwriteWith("hello world", 0);

How to overwrite a string with another string?

4 Answers4