add

问题 I want to fill an ArrayList with these characters +,-,*,^ etc. How can I do this without having to add every character with arrayList.add() ? 回答1: Collections.addAll is what you want. Collections.addAll(myArrayList, '+', '-', '*', '^'); Another option is to pass the list into the constructor using Arrays.asList like this: List<Character> myArrayList = new ArrayList<Character>(Arrays.asList('+', '-', '*', '^')); If, however, you are good with the arrayList being fixed-length, you can go with

问题 the program gives me loss of precision error but i cant think of any precision loss since numbers are small This is the code ## class Demo { public static void main(String args[]) { byte b1=3; byte b2=2; byte b3=b1+b2; System.out.println(b3); } } 回答1: The addition expression b1 + b2 is of type int - there aren't any addition operators defined on smaller types than int . So in order to convert that back to a byte , you have to cast: byte b3 = (byte) (b1 + b2); Note that although you happen to

问题 the program gives me loss of precision error but i cant think of any precision loss since numbers are small This is the code ## class Demo { public static void main(String args[]) { byte b1=3; byte b2=2; byte b3=b1+b2; System.out.println(b3); } } 回答1: The addition expression b1 + b2 is of type int - there aren't any addition operators defined on smaller types than int . So in order to convert that back to a byte , you have to cast: byte b3 = (byte) (b1 + b2); Note that although you happen to

问题 I'm working in this school project. I have two std_logic_vector (31 downto 0) A and B, and I have a variable type std_logic_vector (32 downto 0) and I want to add A+B and put the result in my std_logic_vector with 32 bits. This is my design: library IEEE; use IEEE.STD_LOGIC_1164.ALL; USE ieee.numeric_std.ALL; use ieee.std_logic_arith.all; entity Ej3 is Port ( A : in STD_LOGIC_VECTOR (31 downto 0); B : in STD_LOGIC_VECTOR (31 downto 0); S : out STD_LOGIC_VECTOR (31 downto 0); AluOp : in STD

问题 I'm working in this school project. I have two std_logic_vector (31 downto 0) A and B, and I have a variable type std_logic_vector (32 downto 0) and I want to add A+B and put the result in my std_logic_vector with 32 bits. This is my design: library IEEE; use IEEE.STD_LOGIC_1164.ALL; USE ieee.numeric_std.ALL; use ieee.std_logic_arith.all; entity Ej3 is Port ( A : in STD_LOGIC_VECTOR (31 downto 0); B : in STD_LOGIC_VECTOR (31 downto 0); S : out STD_LOGIC_VECTOR (31 downto 0); AluOp : in STD

问题 My goal is to permanently add an item to an existing AlertDialog. The XML array for the AlertDialog is: <array name="serverchoice"> <item>@string/chicago_server</item> <item>@string/london_server</item> <item>@string/sanjose_server</item> <item>@string/washington_server</item> <item>@string/chicagoq_server</item> <item>@string/londonq_server</item> <item>@string/sanjoseq_server</item> <item>@string/washingtonq_server</item> </array> As you can see it's a list of servers, I'd like a user to be

问题 ASP.NET MVC2 has strong support for using attributes on entities (validation, and extending Html helper class and more). If I generated my Model from the Database using VS2010 EF4 Entity Data Model (edmx and it's cs class), And I want to add attributes on some of the entities. what would be the best practice ? how should I cope with updating the model (adding more fields / tables to the database and merging them into the edmx) - will it keep my attributes or generate a new cs file erasing

问题 I have a fairly simple need to do a conditional update in Solr, which is easily accomplished in MySQL. For example, I have 100 documents with a unique field called <id> I am POSTing 10 documents, some of which may be duplicate <id> s, in which case Solr would update the existing records with the same <id> s I have a field called <dateCreated> and I would like to only update a <doc> if the new <dateCreated> is greated than the old <dateCreated> (this applies to duplicate <id> s only, of course

问题 I am trying to add a class object with a number, but I'm confused on how to go about adding a class object with two numbers. For example, this is my hypothetical add class method: class A: def __add__(self, b): return something I know how to add this so far: object = A() print(object + 1) But, what if I want to add it like this? object = A() print(object + 1 + 2) Should I use *args for the add class method? 回答1: No, you can't use multiple arguments. Python executes each + operator separately,

问题 I want to add the number 1 to all the rows and columns of dataframe. Here's the dataframe: df <- structure(list(units = c(422, 188, 314, 197, 2825, 3210, 450, 117, 291, 161, 113, 259), quantity = c(361, 163, 298, 74, 1997, 2803, 164, 62, 203, 140, 115, 269), KP = c(282, 194, 295, 102, 1772, 1610, 151, 295, 126, 157, 191, 233), level = c(215, 62, 215, 78, 1646, 635, 128, 65, 126, 402, 552, 281)), .Names = c("units", "quantity", "KP", "level"), row.names = c(NA, 12L), class = "data.frame")