Search Results

Search found 3076 results on 124 pages for 'beginner'.

Page 47/124 | < Previous Page | 43 44 45 46 47 48 49 50 51 52 53 54  | Next Page >

  • Error in connection in ruby.

    - by piemesons
    require 'rubygems' require 'mysql' db = Mysql.connect('localhost', 'root', '', 'mohit') //db.rb:4: undefined method `connect' for Mysql:Class (NoMethodError) //undefined method `real_connect' for Mysql:Class (NoMethodError) db.query("CREATE TABLE people ( id integer primary key, name varchar(50), age integer)") db.query("INSERT INTO people (name, age) VALUES('Chris', 25)") begin query = db.query('SELECT * FROM people') puts "There were #{query.num_rows} rows returned" query.each_hash do |h| puts h.inspect end rescue puts db.errno puts db.error end error i am geting is: undefined method `connect' for Mysql:Class (NoMethodError) OR undefined method `real_connect' for Mysql:Class (NoMethodError) EDIT return value of Mysql.methods ["private_class_method", "inspect", "name", "tap", "clone", "public_methods", "object_id", "__send__", "method_defined?", "instance_variable_defined?", "equal?", "freeze", "extend", "send", "const_defined?", "methods", "ancestors", "module_eval", "instance_method", "hash", "autoload?", "dup", "to_enum", "instance_methods", "public_method_defined?", "instance_variables", "class_variable_defined?", "eql?", "constants", "id", "instance_eval", "singleton_methods", "module_exec", "const_missing", "taint", "instance_variable_get", "frozen?", "enum_for", "private_method_defined?", "public_instance_methods", "display", "instance_of?", "superclass", "method", "to_a", "included_modules", "const_get", "instance_exec", "type", "<", "protected_methods", "<=>", "class_eval", "==", "class_variables", ">", "===", "instance_variable_set", "protected_instance_methods", "protected_method_defined?", "respond_to?", "kind_of?", ">=", "public_class_method", "to_s", "<=", "const_set", "allocate", "class", "new", "private_methods", "=~", "tainted?", "__id__", "class_exec", "autoload", "untaint", "nil?", "private_instance_methods", "include?", "is_a?"] return value of Mysql.methods(false) is []... blank array

    Read the article

  • Writing a string which contains " "

    - by dotnetdev
    I have a string from an xml document: <title type="html"> Is there a way for me to write this string like "<title type="html">"? I've had similar problems writing javascript as a string but I did see some solutions in the past (which I can't remember)? Thanks

    Read the article

  • How to use avg function?

    - by Marcelo
    I'm new at php and mysql stuff and i'm trying to use an avg function but i don't know how to. I'm trying to do something like this: mysql_connect(localhost,$username,$password); @mysql_select_db($database) or die ("Did not connect to $database"); mysql_query("AVG(column1) FROM table1 ") or die(mysql_error()); mysql_close(); echo AVG(column1); (Q1)I'd like to see the value printed in the screen, but i'm getting nothing but an error message. How could I print this average on the screen ? (Q2)If I had a column month in my table1, how could I print the averages by the months ? Sorry for any bad English, and thanks for the attention.

    Read the article

  • Java cannot find symbol enum

    - by JDelage
    Hi, I'm modeling a chess game on Java, and I'm having some problem. Here's what the code looks like (the relevant parts): Enum class Couleur.java: public enum Couleur {BLANC, NOIR} Piece.java: public abstract class Piece { (...) public Piece(Couleur couleurParam){ this.couleurPiece = couleurParam; } (...) } And finally Tour.java: public class Tour extends Piece { (...) public Tour(Couleur couleurParam){ super(couleurParam); } (...) } All the .java files are in the same folder. Yet at compile I get a "cannot find symbol symbol : variable NOIR location: class Plateau" (Plateau is the class that instantiates Tour.) Can anyone help me figure out what's wrong here? Many thanks, JDelage

    Read the article

  • convert string to dict using list comprehension in python

    - by Pavel
    I have came across this problem a few times and can't seem to figure out a simple solution. Say I have a string string = "a=0 b=1 c=3" I want to convert that into a dictionary with a, b and c being the key and 0, 1, and 3 being their respective values (converted to int). Obviously I can do this: list = string.split() dic = {} for entry in list: key, val = entry.split('=') dic[key] = int(val) But I don't really like that for loop, It seems so simple that you should be able to convert it to some sort of list comprehension expression. And that works for slightly simpler cases where the val can be a string. dic = dict([entry.split('=') for entry in list]) However, I need to convert val to an int on the fly and doing something like this is syntactically incorrect. dic = dict([[entry[0], int(entry[1])] for entry.split('=') in list]) So my question is: is there a way to eliminate the for loop using list comprehension? If not, is there some built in python method that will do that for me?

    Read the article

  • How do I use "this" in a member function?

    - by Peter Stewart
    I've written a member function of class Node to read a tree of Nodes in postfix order. It will be called by the Node instance which is the root node of the tree. So: N.postfix(); these appear to be illeagal: *this->left.postfix(); *this->right.postfix(); What is the proper way to do this? class Node { public: const char *cargo; int depth; Node *left; Node *right void Node::postfix() { if (this==__nullptr) { return; } else { *this->left.postfix(); *this->right.postfix(); out<<*this->cargo<<"\n"; return; } };

    Read the article

  • Java: design problem with private-final-int-value and empty constructor

    - by HH
    $ javac InitInt.java InitInt.java:7: variable right might not have been initialized InitInt(){} ^ 1 error $ cat InitInt.java import java.util.*; import java.io.*; public class InitInt { private final int right; //DUE to new Klowledge: Design Problem //I think having an empty constructor like this // is an design problem, shall I remove it? What do you think? // When to use an empty constructor? InitInt(){} public static void main(String[] args) { InitInt test = new InitInt(); System.out.println(test.getRight()); } public int getRight(){return right;} } Initialization problem with Constructor InitInt{ // Still the error, "may not be initialized" // How to initialise it? if(snippetBuilder.length()>(charwisePos+25)){ right=charwisePos+25; }else{ right=snippetBuilder.length()-1; } }

    Read the article

  • Java: how to have global values inside a class?

    - by HH
    I want less methods. I want a common global TestClass from which I could use any of its value inside the class. import java.util.*; import java.io.*; public class TestClass { TestClass(String hello){ String hallo = hello; String halloSecond = "Saluto!"; } public static void main(String[] args) { TestClass test = new TestClass("Tjena!"); System.out.println("I want "Tjena!": " + test.hallo); TestClass testSecond = new TestClass("1"); System.out.println("I want Saluto!:" + test.halloSecond); System.out.println("I want Saluto!:" + testSecond.halloSecond); // How can I get glob.vars like the "Saluto!"? } }

    Read the article

  • In DOM is it OK to use .notation for getting/setting attributes?

    - by Ziggy
    Hi In DOM, is it OK to refer to an element's attributes like this: var universe = document.getElementById('universe'); universe.origin = 'big_bang'; universe.creator = null; universe.style.deterministic = true; ? My deep respect for objects and their privacy, and my sense that things might go terribly wrong if I am not careful, makes me want to do everything more like this: var universe = document.getElementById('universe'); if(universe.hasAttribute('origin')) then universe.origin = 'big_bang'; etc... Is it really necessary to use those accessor methods? Of course it may be more or less necessary depending on how certain I am that the elements I am manipulating will have the attributes I expect them to, but in general do the DOM guys consider it OK to use .notation rather than getters and setters? Thanks!

    Read the article

  • How to convert list into a string?

    - by PARIJAT
    I have extracted some data from the file and want to write it in the file 2 but the program says 'sequence item 1: expected string, list found', I want to know how I can convert buffer[] i.e. string into sequence, so that it could be saved in file 2. file = open('/ddfs/user/data/k/ktrip_01/hmm.txt','r') file2 = open('/ddfs/user/data/k/ktrip_01/hmm_write.txt','w') buffer = [] rec = file.readlines() for line in rec : field = line.split() print '>',field[0] term = field[0] buffer.append(term) print field[1], field[2], field[6], field[12] term1 = field [1] buffer.append(term1) term2 = field[2] buffer.append[term2] term3 = field[6] buffer.append[term3] term4 = field[12] buffer.append[term4] file2.write(buffer) file.close() file2.close()

    Read the article

  • Regex, replace path to resource, modify resource name

    - by jerome
    Hi all, I'd like to use a JS regex to take a string such as the following: 'http://www.somedomain.com/some_directory/some_other_directory/some_image.jpg' And turn it into this: 'http://www.some_other_domain.com/another_directory/yet_another_directory/size1_some_image.jpg' Any hints? Additionally, any pointers for books or other resources that give a gentle introduction to mastering regexes in JS and other languages?

    Read the article

  • What's the scope of a Python variable declared in an if statement?

    - by froadie
    I'm new to Python, so this is probably a simple scoping question. The following code in a Python file (module) is confusing me slightly: if __name__ == '__main__': x = 1 print x In other languages I've worked in, this code would throw an exception, as the x variable is local to the if statement and should not exist outside of it. But this code executes, and prints 1. Can anyone explain this behavior? Are all variables declared in a module global/available to the entire module?

    Read the article

  • Would it be faster to use CMS for building the first site in ASP.NET?

    - by rem
    I need an opinion and advise from experienced ASP.NET people, what way to go. Assuming that a developer has some practical background with HTML/JavaScript/PHP on one side and some .NET/C#/WPF experience on the other side. No previous hands on experience with ASP.NET - only theory and some read books on the topic. The task is to build ASP.NET web site with User Managment functionality (user authentication, user account, user buying history, user points and so on) and E-commerce functionality with shopping cart, checkout and all needed for this. Is it worth, i.e. will it be faster, more reliable and secure in the result to use a ASP.NET CMS system (for example Sitefinity from Telerik as declared developer friendly) to build such first site? In what case the learning curve will be more steep and it will take more time to achieve similar results? Notes to take into consideration: 1) Price of the CMS matters not very much 2) E-commerce module should be written from scratch in any case (and integrated in case of using CMS) due to very specific requirements

    Read the article

  • How to handle array element between int and Integer

    - by masato-san
    First, it is long post so if you need clarification please let me know. I'm new to Java and having difficulty deciding whether I should use int[] or Integer[]. I wrote a function that find odd_number from int[] array. public int[] find_odd(int[] arr) { int[] result = new int[arr.length]; for(int i=0; i<arr.length; i++) { if(arr[i] % 2 != 0) { //System.out.println(arr[i]); result[i] = arr[i]; } } return result; } Then, when I pass the int[] array consisting of some integer like below: int[] myArray = {-1, 0, 1, 2, 3}; int[] result = find_odd(myArray); The array "result" contains: 0, -1, 0, 1, 0, 3 Because in Java you have to define the size of array first, and empty int[] array element is 0 not null. So when I want to test the find_odd() function and expect the array to have odd numbers (which it does) only, it throws the error because the array also includes 0s representing "empty cell" as shown above. My test code: public void testFindOddPassValidIntArray() { int[] arr = {-2, -1, 0, 1, 3}; int[] result = findOddObj.find_odd(arr); //check if return array only contain odd number for(int i=0; i<result.length; i++) { if(result[i] != null) { assert is_odd(result[i]) : result[i]; } } } So, my question is should I use int[] array and add check for 0 element in my test like: if(result[i] != 0) { assert is_odd(result[i] : result[i] } But in this case, if find_odd() function is broken and returning 0 by miscalculation, I can't catch it because my test code would only assume that 0 is empty cell. OR should I use Integer[] array whose default is null? How do people deal with this kind of situation?

    Read the article

  • C++ initializing constants and inheritance

    - by pingvinus
    I want to initialize constant in child-class, instead of base class. And use it to get rid of dynamic memory allocation (I know array sizes already, and there will be a few child-classes with different constants). So I try: class A { public: const int x; A() : x(0) {} A(int x) : x(x) {} void f() { double y[this->x]; } }; class B : A { B() : A(2) {} }; Pretty simple, but compiler says: error C2057: expected constant expression How can I say to compiler, that it is really a constant?

    Read the article

  • How to sanely read and dump structs to disk when some fields are pointers?

    - by bp
    Hello, I'm writing a FUSE plugin in C. I'm keeping track of data structures in the filesystem through structs like: typedef struct { block_number_t inode; filename_t filename; //char[SOME_SIZE] some_other_field_t other_field; } fs_directory_table_item_t; Obviously, I have to read (write) these structs from (to) disk at some point. I could treat the struct as a sequence of bytes and do something like this: read(disk_fd, directory_table_item, sizeof(fs_directory_table_item_t)); ...except that cannot possibly work as filename is actually a pointer to the char array. I'd really like to avoid having to write code like: read(disk_df, *directory_table_item.inode, sizeof(block_number_t)); read(disk_df, directory_table_item.filename, sizeof(filename_t)); read(disk_df, *directory_table_item.other_field, sizeof(some_other_field_t)); ...for each struct in the code, because I'd have to replicate code and changes in no less than three different places (definition, reading, writing). Any DRYer but still maintainable ideas?

    Read the article

  • wsgi-served page does not refresh

    - by Steve
    I recently got my first app to work in uWSGI with Cherokee. I used the following code taken from the uWSGI docs: def application(environ, start_response): start_response('200 OK', [('Content-Type', 'text/plain')]) yield 'Hello World\n' The page correctly reads Hello World. When I change that text to New Thing and refresh, nothing changes. What am I forgetting? What I've tried: clearing browser history and cache stopping and starting Cherokee

    Read the article

  • What benefits can Java developer have moving to a *NIX platform?

    - by dave-keiture
    Hi everyone, A friend of mine is a Java developer, who's using *NIX for ages. He claims that *NIX is for real Java geeks, whereas WIN is for dummies (and I'm one of them, according to him) and girls. When I ask him to argue his position, and explain, what's so good for Java developer on *NIX, he starts talking about console, wget, curl and grep. But sorry, wget and curl analogues exist for the WIN platform as well. As for the console - I'm using FAR Commander, and have access to the command line when I need. Moreover, even if I decide moving to *NIX, I will certainly use Netbeans or Eclipse there, so there will be no big difference. Guys, who use Java on *NIX, could you please give me a real killer examples, when *NIX (any util or technique) dramatically increases Java development productivity (in the way the hints are given in "The Pragmatic Programmer"), or, which is also important, gives more fun from the process. Thanks in advance!

    Read the article

  • How can I "override" deepcopy in Python?

    - by Az
    Hi there, I'd like to override __deepcopy__ for a given SQLAlchemy-mapped class such that it ignores any SQLA attributes but deepcopies everything else that's part of the class. I'm not particularly familiar with overriding any of Python's built-in objects in particular but I've got some idea as to what I want. Let's just make a very simple class User that's mapped using SQLA. class User(object): def __init__(self, user_id, name): self.user_id = user_id self.name = name I've used dir() to see, before and after mapping, what SQLAlchemy-specific attributes there are and I've found _sa_class_manager and _sa_instance_state. Provided those are the only ones how would I ignore that when defining __deepcopy__? Also, are there any attributes the SQLA injects into the mapped object? (I asked this in a previous question (as an edit a few days after I selected an answer to the main question, though) but I think I missed the train there. Apologies for that.)

    Read the article

  • How to use Scanner to accept only valid int as input

    - by John
    I'm trying to make a small program more robust and I need some help with that. Scanner kb = new Scanner(System.in); int num1; int num2 = 0; System.out.print("Enter number 1: "); num1 = kb.nextInt(); while(num2<num1) { System.out.print("Enter number 2: "); num2 = kb.nextInt(); } Number 2 has to be greater than number 1 Also I want the program to automatically check and ignore if the user enters a character instead of a number. Because right now when a user enters for example r instead of a number the program just exits.

    Read the article

  • vector related memory allocation question

    - by memC
    hi all, I am encountering the following bug. I have a class Foo . Instances of this class are stored in a std::vector vec of class B. in class Foo, I am creating an instance of class A by allocating memory using new and deleting that object in ~Foo(). the code compiles, but I get a crash at the runtime. If I disable delete my_a from desstructor of class Foo. The code runs fine (but there is going to be a memory leak). Could someone please explain what is going wrong here and suggest a fix? thank you! class A{ public: A(int val); ~A(){}; int val_a; }; A::A(int val){ val_a = val; }; class Foo { public: Foo(); ~Foo(); void createA(); A* my_a; }; Foo::Foo(){ createA(); }; void Foo::createA(){ my_a = new A(20); }; Foo::~Foo(){ delete my_a; }; class B { public: vector<Foo> vec; void createFoo(); B(){}; ~B(){}; }; void B::createFoo(){ vec.push_back(Foo()); }; int main(){ B b; int i =0; for (i = 0; i < 5; i ++){ std::cout<<"\n creating Foo"; b.createFoo(); std::cout<<"\n Foo created"; } std::cout<<"\nDone with Foo creation"; std::cout << "\nPress RETURN to continue..."; std::cin.get(); return 0; }

    Read the article

< Previous Page | 43 44 45 46 47 48 49 50 51 52 53 54  | Next Page >