Mutable and Immutable String Class

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C#

What is the difference between mutable and immutable String class?

Why Data always flows as string but not as number?

Posted 10-Sep-11 16:41pm

djrocks0101

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2 solutions

Solution 2

We are now that strings are reference type in .net. Due to this fact, they are allocated on heap and when in the scope their pointer come on to the stack. When we try and assign a new value to a string variable, we can get the new value assigned to our variable, but in the background, a new memory location is allocated and its reference is copied to out string variable making us feel that the value of the original one is changed. This feature is referred as immutable. Thus all string in .net are immutable.

Due to this behavior of string we should always use StringBuilder class present in System.IO.Text namespace where we thing we need lot of string manipulation. This class has lot of methods that we can use to manipulate the strings.

We can get our string using the following code

C#

StringBuilder sb=new StringBuilder();
//do some stuff like string manipulation here
string s=db.ToString();

The data in the backend flows mostly in form of binary or xml strings if it flows between processes but flows as given type if it is inproc call.

Hope this helps

Thanks

Posted 10-Sep-11 20:15pm

Sunil Pandita

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-09-10T17:49:00

Solution 1

1) All strings in .NET are immutable. You never can change a content of any string. All string operations create a brand-new string. Keep it in mind when using string operations, especially highly misused concatenation ("+").

Compare:

C#

string myString = "Immutable";
char charI = myString[0]; //you can do it
//myString[0] = ' '; myString[1] = ' '; no way; it is immutable

//array of char can be considered as some kind of string; it is mutable:
char[] myText = new char['M', 'u', 't', 'a', 'b', 'l', 'e', ' ', ];
myText[7] = '!'; //you can do it! The result will be "Mutable!"

In you want to concatenate strings repeatedly, always use System.Text.StringBuilder. More generally, whenever you need some effects of mutable string data, use this class. This class is not a string though; it's a container of character data with operations which you can convert to string via object.ToString().

2) Not true. There is no "why". If flows how you define it.

—SA

Posted 10-Sep-11 17:49pm

Sergey Alexandrovich Kryukov

Updated 10-Sep-11 17:52pm

v3

Comments

Mehdi Gholam 11-Sep-11 0:52am

My 5!

Sergey Alexandrovich Kryukov 11-Sep-11 15:19pm

Thank you, Mehdi.
--SA

djrocks0101 11-Sep-11 1:44am

Thanks SAKryukov..My 5!

Sergey Alexandrovich Kryukov 11-Sep-11 15:20pm

You are welcome and thank you.
Good luck, call again.
--SA

Uday P.Singh 11-Sep-11 3:01am

my 5!

Sergey Alexandrovich Kryukov 11-Sep-11 15:20pm

Thank you, Uday.
--SA

BillWoodruff 11-Sep-11 6:21am

+5 Right on, SAK ! I can't helping thinking, in response to the OP's mention of how data "flows," that it "flows" depending on how you look at it: 'atomically' as sequences of ones-and-zeroes; 'molecularly' as bytes, and then 'as compounds' of higher abstractions ... silly thought ? :) And in the future: data will flow fractally in entanglements of cubits, which I am pretty sure I won't live to see, and certainly will never understand.

Sergey Alexandrovich Kryukov 11-Sep-11 15:36pm

Thank you, Bill.

Well, data "flow" indeed depends on how you look at it, nothing wrong with this idea. However, it looks like OP concern is simpler: does binary serialization exist (where numbers "flow" as bit patterns, not in their human-readable string presentation) or not. The answer is "yes"; you can serialize anything in every way or combination of ways. Well, don't mix cubits and fractals; what they have in common? Both words are fancy?

Now, speaking of the fractals and about the idea "depending on how you look at it": I once noticed, that, for example, the computer notion of "dimension" depends on the level of your education or on how fundamental your approach is: the dimension is lower when your level is deeper. For example, the novice think that they work with 3D images and the data is presented in the form of 3D arrays. The one who knows how arrays are presented in memory will understand that all arrays are single-dimensional structures. Finally, the one who understand better how computers work and the one able to work with dimensions in metric space and Hausdorff dimension (aka Hausdorff–Besicovitch dimension, http://en.wikipedia.org/wiki/Hausdorff_dimension) will tell you that all programming objects are zero-dimensional. Ultimately, all the finite sets of any nature are zero-dimensional, as well as some infinite number of infinite sets.

(Look at the references article; in particular, it gives clear explanation on how fractals are measured in dimension.)

--SA