string-concatenation

问题 I have know the invokedynamic instruction. Also I have known the basic process how it implements. But when I arrive the code. I can't understand the code in StringConcatFactory . Can you tell me how the six strategies implements by the source code. Only the default strategy is also done. As a university student, I can't under the source code. private enum Strategy { /** * Bytecode generator, calling into {@link java.lang.StringBuilder}. */ BC_SB, /** * Bytecode generator, calling into {@link

问题 I have this file called db.php which makes the connection to the database. <?php define("DB_HOST", "localhost"); define("DB_NAME", "login"); define("DB_USER", "admin"); define("DB_PASS", "123"); mysql_connect(DB_HOST, DB_USER, DB_PASS) OR die("Falha na ligação."); ?> What I wanted to do is to use that DB_NAME define in another file so that I just need to change it in the db.php in case I have to change the database name. Here's an example of where I want it to be aplied. $qp = "UPDATE login

问题 I have a dataset of the following type (first row is the header): content is always text merge is always a logical id1 id2 start_line end_line content merge A B 1 1 "aaaa" TRUE A B 4 4 "aa mm" TRUE A B 5 5 "boool" TRUE A B 6 6 "omw" TRUE C D 6 6 "hear!" TRUE C D 7 7 " me out!" TRUE C D 21 21 "hello" FALSE Problem: I need to merge following a very specific criteria: Rows that have merge = FALSE must remain as is Rows that have: same id1 , same id2 and consecutive start_line : Need to be

问题 I need to print ' H3110 w0r1d 2.0 true ' as output. Below is the code written and getting output as '3182 w0r1d 2.0 true'. public class HelloWorld { public static void main (String[] args){ char c1= 'H'; int num1 = 3110; char c2='w'; byte b=0; char c3='r'; int y=1; char c4='d'; float f = 2.0f; boolean bool= true; String s = c1+num1 + " " + c2+b+c3+y+c4 + " " + f + " " + bool; System.out.println(s); } } Query: If I concatenate H and 3110 , it is printing as 3182 . Why so? 回答1: The + operator

问题 I need to print ' H3110 w0r1d 2.0 true ' as output. Below is the code written and getting output as '3182 w0r1d 2.0 true'. public class HelloWorld { public static void main (String[] args){ char c1= 'H'; int num1 = 3110; char c2='w'; byte b=0; char c3='r'; int y=1; char c4='d'; float f = 2.0f; boolean bool= true; String s = c1+num1 + " " + c2+b+c3+y+c4 + " " + f + " " + bool; System.out.println(s); } } Query: If I concatenate H and 3110 , it is printing as 3182 . Why so? 回答1: The + operator

问题 I need to print ' H3110 w0r1d 2.0 true ' as output. Below is the code written and getting output as '3182 w0r1d 2.0 true'. public class HelloWorld { public static void main (String[] args){ char c1= 'H'; int num1 = 3110; char c2='w'; byte b=0; char c3='r'; int y=1; char c4='d'; float f = 2.0f; boolean bool= true; String s = c1+num1 + " " + c2+b+c3+y+c4 + " " + f + " " + bool; System.out.println(s); } } Query: If I concatenate H and 3110 , it is printing as 3182 . Why so? 回答1: The + operator

问题 How can I combine this code with all single and double quotes as it should be. I have tried several combinations and I can't make it work. This one is my last try so please help. What would be a good approach when working with long strings? $html .='<a href="" onClick="$.ajax({type: "POST",url: "delete_pic.php",data:{id:"'.$row['id'].'",var:"V"},cache: false});" style="background:url("images/icons/delete.png" 50% -19px no-repeat;width:16px;height:16px;float:left;margin-left:10px;margin-top:

问题 This is the converse of the problem "Why is String concatenation faster than String.valueOf for converting an Integer to a String?". It is not a duplicate. Rather, it stems from this answer with benchmarks asserting that t.setText(String.valueOf(number)) is faster than t.setText(""+number) , and ChristianB's question as to why that is. 回答1: String addition results in the compiler creating a StringBuilder instance, followed by append calls for each added element, followed by a call to

问题 This question already has answers here : String valueOf vs concatenation with empty string (10 answers) Closed 3 years ago . I want to know the difference in two approaches. There are some old codes on which I'm working now, where they are setting primitive values to a String value by concatenating with an empty String "" . obj.setSomeString("" + primitiveVariable); But in this link Size of empty Java String it says that If you're creating a separate empty string for each instance, then

问题 I have a list of strings and I am concatenating it to flatten out the list by using the method seen here on DotNetPerls, http://www.dotnetperls.com/string-concat My question is...in their List example where their output is "catdogperls" (see toward the bottom of the webpage, just before the Summary) how do I insert a # sign as a separator between "catdogperls" such that it becomes "cat#dog#perls"? 回答1: In this case you don't want to use string.Concat() , you want to use string.Join(). This