Difference between string.empty and null

Question

1.33/5 (2 votes)

See more:

C#

C#4.0

Hi Everyone....
Can anyone tell me what is difference between sting a=string.empty and string b="" ?

Posted 15-Oct-13 8:07am

1989priya

Add a Solution

Comments

Sergey Alexandrovich Kryukov 15-Oct-13 15:10pm

Now, it's null vs. "". vs. String.Empty. (And string.empty would not even compile. Is it another option? :-)
"" is not null.
What's wrong with reading some documentation before you ask a question?
—SA

Bernhard Hiller 16-Oct-13 2:39am

Also note that beyond the programming concepts of null and empty strings, they may be the same from a requirements point of view: the user did not provide data. Just llok at the "paper" version of the work flow: if a user does not fill in a field, is it empty or null?
I guess that that's also the reason why Oracle database does not allow an empty string when the column has a NOT NULL constraint.

3 solutions

Solution 4

The difference is the same as writing the question with empty text (I hope this is prevented by CodeProject software though) and not posting any question at all. Note that the second option would be much better: you could easily learn this matter by reading original documentation.

Note that the question is inconsistent (please see my comment to the question and other answers).

The problem with null is trivial, but "" vs. String.Empty is not so simple. First would work like immediate constant and the second one is the read-only field. They make the same result, but due to a very non-trivial feature of strings, specifically: string interning. Please see:
http://en.wikipedia.org/wiki/String_interning[^],
http://broadcast.oreilly.com/2010/08/understanding-c-stringintern-m.html[^].

In not intern pool, we could possibly end up having multiple "" strings in different parts of code. With intern pool, it doesn't happen.

Practically, it's important to use String.Empty, not an immediate constant. Immediate constants make code dirty, are bad for maintenance. Exclusions could be made for immediate constants like 0, 1 and null, but never "". Imaging you want to remove all hard-coded strings from the code, using text search. Would be a good idea. And then "" will get in your search result, so it's better to get rid of them in the very beginning.

—SA

Posted 15-Oct-13 9:08am

Sergey Alexandrovich Kryukov

Updated 15-Oct-13 9:21am

v4

Solution 1

Read the following : http://stackoverflow.com/questions/151472/what-is-the-difference-between-string-empty-and-empty-string[^]

Posted 15-Oct-13 8:08am

Mehdi Gholam

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

**Zoltán Zörgő** · Accepted Answer · 2013-10-15T08:35:00

Your title and the text contain two different questions.

String.Empty and "" are the same from programming point of view. See: http://msdn.microsoft.com/en-us/library/system.string.empty.aspx[^]

A string is an object, something that has reserved space in memory. The variable itself contains a reference to that address space (sort of). If a reference (the variable's very own value) is null, that means that the content it is referring to (the string itself) does not exist. It is uninitialized. While both string.Empty, String.Empty and "" mean that the string itself is initialized with an empty (zero-length) value.