String combination and complexity?

Question

When I need to join two strings, I use String.Format (or StringBuilder if this happens in several places in the code).

I see that some good programmers do not pay attention to the complexity of the lines and simply use the "+" operator.

I know that using the + operator causes the application to use more memory, but what about complexity?

Answer 1

This is a great article on the different methods of combining strings of our own Jeff Atwood about Coding Horror :

_{(source: codinghorror.com )}

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Answer 2

, .

+ , , . , , , O (n ^ 2).

, , :

string foo = "a";
for(int i = 0; i < 1000; i++)
{
    foo += "a";
}

, foo ( "a" ) , "a" . . ; foo "a" . 1000- 1001 . 2 + 3 + ... + 1001. , ( ), n, 2 + 3 + ... + n + 1 . , 1 + 2 + 3 + ... + n = n(n+1)/2 = (n^2 + n)/2, O (n ^ 2).

Answer 3

. + . :

output = "<p>" + intro + "</p>";

, . String.Format.

Answer 4

+ , , ( ).

, : ( ).

, + ( , 2 . "<p>" , "</p>" .

, . , , , intro - .

Answer 5

, . axample "A" + "B" + "C" + "D" , "A", "AB" , , "ABC", "ABCD". - , ? , , , 1000 , , (1000 + N) 1000 . O (n ^ 2) .

Strin.Fomat, , StringBuffer O (n).

Answer 6

StringBuilder , . , , , . +, ( )

Answer 7

(, , !), . .

Answer 8

, Java #, , , , .

, , c.

2 * c , n-1, (n-1) * c , , c , n * c. n n ^ 2 * c/2 , O (n ^ 2).

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, , O (n ^ 2) .

, , Word XML , base64. 10 - O (n ^ 2). , + StringBuilder, 10 .

, , SQL , + . , ( ), StringBuilder. .

, , / , , : -)

Answer 9

: "a" + "b" + "c" String.Concat( String.Format )

Answer 10

, , - , , , .

, Big O, , , ( , ), . strA + strB strA.Append(strB) 100 000 , , .

Answer 11

. :

string s = "a" + "b" + "c";

:

string s = "abc";

. MSDN.

Answer 12

, .NET 1.0 1.1.

Then, if you had some kind of process that was about to hit a line of code that would be a concatenating string several million times, you could get a huge speed increase with String.Concat, String.Format or StringBuilder.

Now it does not matter. At least it didn't matter, since .Net 2.0 came out anyway. Take it out of your mind and code to make it easier for you to read.