Foo(int num): bar(num)
This construct is called a Member Initializer List in C++.
Simply said, it initializes your member bar
to a value num
.
Member Initialization:
Foo(int num): bar(num) {};
Member Assignment:
Foo(int num)
{
bar = num;
}
There is a significant difference between Initializing a member using Member initializer list and assigning it an value inside the constructor body.
When you initialize fields via Member initializer list the constructors will be called once and the object will be constructed and initialized in one operation.
If you use assignment then the fields will be first initialized with default constructors and then reassigned (via assignment operator) with actual values.
As you see there is an additional overhead of creation & assignment in the latter, which might be considerable for user defined classes.
Cost of Member Initialization = Object Construction
Cost of Member Assignment = Object Construction + Assignment
The latter is actually equivalent to:
Foo(int num) : bar() {bar = num;}
While the former is equivalent to just:
Foo(int num): bar(num){}
For an inbuilt (your code example) or POD class members there is no practical overhead.
You will have(rather forced) to use a Member Initializer list if:
class MyClass {
public:
// Reference member, has to be Initialized in Member Initializer List
int &i;
int b;
// Non static const member, must be Initialized in Member Initializer List
const int k;
// Constructor’s parameter name b is same as class data member
// Other way is to use this->b to refer to data member
MyClass(int a, int b, int c) : i(a), b(b), k(c) {
// Without Member Initializer
// this->b = b;
}
};
class MyClass2 : public MyClass {
public:
int p;
int q;
MyClass2(int x, int y, int z, int l, int m) : MyClass(x, y, z), p(l), q(m) {}
};
int main() {
int x = 10;
int y = 20;
int z = 30;
MyClass obj(x, y, z);
int l = 40;
int m = 50;
MyClass2 obj2(x, y, z, l, m);
return 0;
}
MyClass2
doesn't have a default constructor so it has to be initialized through member initializer list.MyClass
does not have a default constructor, So to initialize its member one will need to use Member Initializer List.Class Member variables are always initialized in the order in which they are declared in the class.
They are not initialized in the order in which they are specified in the Member Initializer List.
In short, Member initialization list does not determine the order of initialization.
Given the above it is always a good practice to maintain the same order of members for Member initialization as the order in which they are declared in the class definition. This is because compilers do not warn if the two orders are different but a relatively new user might confuse member Initializer list as the order of initialization and write some code dependent on that.
Although it doesn't apply to this specific example, Option 1 allows you to initialize member variables of reference type (or const
type, as pointed out below). Option 2 doesn't. In general, Option 1 is the more powerful approach.
Use the constructor because "When the constructor is finished, Construction should be finished". properties are like states your classes hold, if you had to initialize a default state, you would do that in your constructor.
Yes, you can call constructors from another constructor. For example:
public class Animal {
private int animalType;
public Animal() {
this(1); //here this(1) internally make call to Animal(1);
}
public Animal(int animalType) {
this.animalType = animalType;
}
}
you can also read in details from Constructor Chaining in Java
The first line of a constructor is always an invocation to another constructor. You can choose between calling a constructor from the same class with "this(...)" or a constructor from the parent clas with "super(...)". If you don't include either, the compiler includes this line for you: super();
Maybe your class isn't quite complete. Personally, I use a private init() function with all of my overloaded constructors.
class Point2D {
double X, Y;
public Point2D(double x, double y) {
init(x, y);
}
public Point2D(Point2D point) {
if (point == null)
throw new ArgumentNullException("point");
init(point.X, point.Y);
}
void init(double x, double y) {
// ... Contracts ...
X = x;
Y = y;
}
}
It sounds like you want the object parameter to be optional, and also each of the properties in the object to be optional. In the example, as provided, overload syntax isn't needed. I wanted to point out some bad practices in some of the answers here. Granted, it's not the smallest possible expression of essentially writing box = { x: 0, y: 87, width: 4, height: 0 }
, but this provides all the code hinting niceties you could possibly want from the class as described. This example allows you to call a function with one, some, all, or none of the parameters and still get default values.
/** @class */
class Box {
public x?: number;
public y?: number;
public height?: number;
public width?: number;
constructor(params: Box = {} as Box) {
// Define the properties of the incoming `params` object here.
// Setting a default value with the `= 0` syntax is optional for each parameter
let {
x = 0,
y = 0,
height = 1,
width = 1
} = params;
// If needed, make the parameters publicly accessible
// on the class ex.: 'this.var = var'.
/** Use jsdoc comments here for inline ide auto-documentation */
this.x = x;
this.y = y;
this.height = height;
this.width = width;
}
}
Need to add methods? A verbose but more extendable alternative:
The Box
class above can work double-duty as the interface since they are identical. If you choose to modify the above class, you will need to define and reference a new interface for the incoming parameters object since the Box
class no longer would look exactly like the incoming parameters. Notice where the question marks (?:
) denoting optional properties move in this case. Since we're setting default values within the class, they are guaranteed to be present, yet they are optional within the incoming parameters object:
interface BoxParams {
x?: number;
// Add Parameters ...
}
class Box {
public x: number;
// Copy Parameters ...
constructor(params: BoxParams = {} as BoxParams) {
let { x = 0 } = params;
this.x = x;
}
doSomething = () => {
return this.x + this.x;
}
}
Whichever way you choose to define your class, this technique offers the guardrails of type safety, yet the flexibility write any of these:
const box1 = new Box();
const box2 = new Box({});
const box3 = new Box({x:0});
const box4 = new Box({x:0, height:10});
const box5 = new Box({x:0, y:87,width:4,height:0});
// Correctly reports error in TypeScript, and in js, box6.z is undefined
const box6 = new Box({z:0});
Compiled, you see how the default settings are only used if an optional value is undefined; it avoids the pitfalls of a widely used (but error-prone) fallback syntax of var = isOptional || default;
by checking against void 0
, which is shorthand for undefined
:
var Box = (function () {
function Box(params) {
if (params === void 0) { params = {}; }
var _a = params.x, x = _a === void 0 ? 0 : _a, _b = params.y, y = _b === void 0 ? 0 : _b, _c = params.height, height = _c === void 0 ? 1 : _c, _d = params.width, width = _d === void 0 ? 1 : _d;
this.x = x;
this.y = y;
this.height = height;
this.width = width;
}
return Box;
}());
||
(or) operatorConsider the danger of ||
/or operators when setting default fallback values as shown in some other answers. This code below illustrates the wrong way to set defaults. You can get unexpected results when evaluating against falsey values like 0, '', null, undefined, false, NaN:
var myDesiredValue = 0;
var result = myDesiredValue || 2;
// This test will correctly report a problem with this setup.
console.assert(myDesiredValue === result && result === 0, 'Result should equal myDesiredValue. ' + myDesiredValue + ' does not equal ' + result);
In my tests, using es6/typescript destructured object can be 15-90% faster than Object.assign. Using a destructured parameter only allows methods and properties you've assigned to the object. For example, consider this method:
class BoxTest {
public x?: number = 1;
constructor(params: BoxTest = {} as BoxTest) {
Object.assign(this, params);
}
}
If another user wasn't using TypeScript and attempted to place a parameter that didn't belong, say, they might try putting a z
property
var box = new BoxTest({x: 0, y: 87, width: 4, height: 0, z: 7});
// This test will correctly report an error with this setup. `z` was defined even though `z` is not an allowed property of params.
console.assert(typeof box.z === 'undefined')
You need a parameterless constructor to be able to create an instance of your class. Your current constructor requires two input string parameters.
Normally C++ implies having such a constructor (=default parameterless constructor) if there is no other constructor declared. By declaring your first constructor with two parameters you overwrite this default behaviour and now you have to declare this constructor explicitly.
Here is the working code:
#include <iostream>
#include <string> // <-- you need this if you want to use string type
using namespace std;
class name {
public:
string first;
string last;
name(string a, string b){
first = a;
last = b;
}
name () // <-- this is your explicit parameterless constructor
{}
};
int main (int argc, const char * argv[])
{
const int howManyNames = 3;
name someName[howManyNames];
return 0;
}
(BTW, you need to include to make the code compilable.)
An alternative way is to initialize your instances explicitly on declaration
name someName[howManyNames] = { {"Ivan", "The Terrible"}, {"Catherine", "The Great"} };
The problem is that the base class foo
has no parameterless constructor. So you must call constructor of the base class with parameters from constructor of the derived class:
public bar(int a, int b) : base(a, b)
{
c = a * b;
}
Regarding the alternative to super; you'd in most cases use use the base class either in the initialization list of the derived class, or using the Base::someData
syntax when you are doing work elsewhere and the derived class redefines data members.
struct Base
{
Base(char* name) { }
virtual ~Base();
int d;
};
struct Derived : Base
{
Derived() : Base("someString") { }
int d;
void foo() { d = Base::d; }
};
If you need to call the base constructor but not right away because your new (derived) class needs to do some data manipulation, the best solution is to resort to factory method. What you need to do is to mark private your derived constructor, then make a static method in your class that will do all the necessary stuff and later call the constructor and return the object.
public class MyClass : BaseClass
{
private MyClass(string someString) : base(someString)
{
//your code goes in here
}
public static MyClass FactoryMethod(string someString)
{
//whatever you want to do with your string before passing it in
return new MyClass(someString);
}
}
Error handling and making your code reusable is key. I added string to int validation and it is possible to add other types if needed. Solving this problem with a more reusable solution could be this:
public class Sample
{
public Sample(object inputToInt)
{
_intField = objectToInt(inputToInt);
}
public int IntProperty => _intField;
private readonly int _intField;
}
public static int objectToInt(object inputToInt)
{
switch (inputToInt)
{
case int inputInt:
return inputInt;
break;
case string inputString:
if (!int.TryParse(inputString, out int parsedInt))
{
throw new InvalidParameterException($"The input {inputString} could not be parsed to int");
}
return parsedInt;
default:
throw new InvalidParameterException($"Constructor do not support {inputToInt.GetType().Name}");
break;
}
}
You declared the constructor blowfish as this:
Blowfish(BlowfishAlgorithm algorithm);
So this line cannot exist (without further initialization later):
Blowfish _blowfish;
since you passed no parameter. It does not understand how to handle a parameter-less declaration of object "BlowFish" - you need to create another constructor for that.
Or you can use a data file to put many person objects in to a list or array. You do need to use the System.IO for this. And you need a data file which contains all the information about the objects.
A method for it would look something like this:
static void ReadFile()
{
using(StreamWriter writer = new StreamWriter(@"Data.csv"))
{
string line = null;
line = reader.ReadLine();
while(null!= (line = reader.ReadLine())
{
string[] values = line.Split(',');
string name = values[0];
int age = int.Parse(values[1]);
}
Person person = new Person(name, age);
}
}
I use an enum with no instances
public enum MyUtils {
; // no instances
// class is final and the constructor is private
public static int myUtilityMethod(int x) {
return x * x;
}
}
you can call this using
int y = MyUtils.myUtilityMethod(5); // returns 25.
Another simple solution could be to use a structure or simple data class that contains the parameters as properties; that way you can have all the default values and behaviors set up ahead of time, passing the "parameter class" in as the single constructor parameter:
public class FooParams
{
public int Size...
protected myCustomStruct _ReasonForLife ...
}
public class Foo
{
private FooParams _myParams;
public Foo(FooParams myParams)
{
_myParams = myParams;
}
}
This avoids the mess of multiple constructors (sometimes) and gives strong typing, default values, and other benefits not provided by a parameter array. It also makes it easy to carry forward since anything that inherits from Foo can still get to, or even add to, FooParams as needed. You still need to copy the constructor, but you always (most of the time) only (as a general rule) ever (at least, for now) need one constructor.
public class Bar : Foo
{
public Bar(FooParams myParams) : base(myParams) {}
}
I really like the overloaded Initailize() and Class Factory Pattern approaches better, but sometimes you just need to have a smart constructor. Just a thought.
If you mean if you can do ctor chaining in C#, the answer is yes. The question has already been asked.
However it seems from the comments, it seems what you really intend to ask is
'Can I call an overloaded constructor from within another constructor with pre/post processing?'
Although C# doesn't have the syntax to do this, you could do this with a common initialization function (like you would do in C++ which doesn't support ctor chaining)
class A
{
//ctor chaining
public A() : this(0)
{
Console.WriteLine("default ctor");
}
public A(int i)
{
Init(i);
}
// what you want
public A(string s)
{
Console.WriteLine("string ctor overload" );
Console.WriteLine("pre-processing" );
Init(Int32.Parse(s));
Console.WriteLine("post-processing" );
}
private void Init(int i)
{
Console.WriteLine("int ctor {0}", i);
}
}
With Python 2.x old-style classes it would be this:
class A:
def __init__(self):
print "world"
class B(A):
def __init__(self):
print "hello"
A.__init__(self)
Private Constructors can be defnied in the Java for the following reasons
To have control on the instantiation of the Java objects, it wont allow you to create an instance of an object.
It wont allow the class to be Subclassed
This has a special advantage when implementing the singleton Pattern, Private contstructors are used for it and have a control on the creating the instance for the whole application.
when you want to have a class with all constants defined and Does not require its instance any more, then we declare that class as a private constructor.
Do not use Class.newInstance()
; see this thread: Why is Class.newInstance() evil?
Like other answers say, use Constructor.newInstance()
instead.
You can. But by placing this in the constructor you are making your object hard to test.
Instead you should:
init()
methodDependency injection frameworks give you these options.
public class ConfigurableObject {
private Map<String, String> configuration;
public ConfigurableObject() {
}
public void setConfiguration(..) {
//...simply set the configuration
}
}
An example of the 2nd option (best used when the object is managed by a container):
public class ConfigurableObject {
private File configFile;
private Map<String, String> configuration;
public ConfigurableObject(File configFile) {
this.configFile = configFile;
}
public void init() {
this.configuration = parseConfig(); // implement
}
}
This, of course, can be written by just having the constructor
public ConfigurableObject(File configfile) {
this.configuration = parseConfig(configFile);
}
But then you won't be able to provide mock configurations.
I know the 2nd opttion sounds more verbose and prone to error (if you forget to initialize). And it won't really hurt you that much if you do it in a constructor. But making your code more dependency-injection oriented is generally a good practice.
The 1st option is best - it can be used with both DI framework and with manual DI.
Simply put, this is wrong because it unnecessarily opens up possibilities to MANY bugs. When the @Override
is invoked, the state of the object may be inconsistent and/or incomplete.
A quote from Effective Java 2nd Edition, Item 17: Design and document for inheritance, or else prohibit it:
There are a few more restrictions that a class must obey to allow inheritance. Constructors must not invoke overridable methods, directly or indirectly. If you violate this rule, program failure will result. The superclass constructor runs before the subclass constructor, so the overriding method in the subclass will be invoked before the subclass constructor has run. If the overriding method depends on any initialization performed by the subclass constructor, the method will not behave as expected.
Here's an example to illustrate:
public class ConstructorCallsOverride {
public static void main(String[] args) {
abstract class Base {
Base() {
overrideMe();
}
abstract void overrideMe();
}
class Child extends Base {
final int x;
Child(int x) {
this.x = x;
}
@Override
void overrideMe() {
System.out.println(x);
}
}
new Child(42); // prints "0"
}
}
Here, when Base
constructor calls overrideMe
, Child
has not finished initializing the final int x
, and the method gets the wrong value. This will almost certainly lead to bugs and errors.
Constructors with many parameters can lead to poor readability, and better alternatives exist.
Here's a quote from Effective Java 2nd Edition, Item 2: Consider a builder pattern when faced with many constructor parameters:
Traditionally, programmers have used the telescoping constructor pattern, in which you provide a constructor with only the required parameters, another with a single optional parameters, a third with two optional parameters, and so on...
The telescoping constructor pattern is essentially something like this:
public class Telescope {
final String name;
final int levels;
final boolean isAdjustable;
public Telescope(String name) {
this(name, 5);
}
public Telescope(String name, int levels) {
this(name, levels, false);
}
public Telescope(String name, int levels, boolean isAdjustable) {
this.name = name;
this.levels = levels;
this.isAdjustable = isAdjustable;
}
}
And now you can do any of the following:
new Telescope("X/1999");
new Telescope("X/1999", 13);
new Telescope("X/1999", 13, true);
You can't, however, currently set only the name
and isAdjustable
, and leaving levels
at default. You can provide more constructor overloads, but obviously the number would explode as the number of parameters grow, and you may even have multiple boolean
and int
arguments, which would really make a mess out of things.
As you can see, this isn't a pleasant pattern to write, and even less pleasant to use (What does "true" mean here? What's 13?).
Bloch recommends using a builder pattern, which would allow you to write something like this instead:
Telescope telly = new Telescope.Builder("X/1999").setAdjustable(true).build();
Note that now the parameters are named, and you can set them in any order you want, and you can skip the ones that you want to keep at default values. This is certainly much better than telescoping constructors, especially when there's a huge number of parameters that belong to many of the same types.
I've always considered throwing checked exceptions in the constructor to be bad practice, or at least something that should be avoided.
The reason for this is that you cannot do this :
private SomeObject foo = new SomeObject();
Instead you must do this :
private SomeObject foo;
public MyObject() {
try {
foo = new SomeObject()
} Catch(PointlessCheckedException e) {
throw new RuntimeException("ahhg",e);
}
}
At the point when I'm constructing SomeObject I know what it's parameters are so why should I be expected to wrap it in a try catch? Ahh you say but if I'm constructing an object from dynamic parameters I don't know if they're valid or not. Well, you could... validate the parameters before passing them to the constructor. That would be good practice. And if all you're concerned about is whether the parameters are valid then you can use IllegalArgumentException.
So instead of throwing checked exceptions just do
public SomeObject(final String param) {
if (param==null) throw new NullPointerException("please stop");
if (param.length()==0) throw new IllegalArgumentException("no really, please stop");
}
Of course there are cases where it might just be reasonable to throw a checked exception
public SomeObject() {
if (todayIsWednesday) throw new YouKnowYouCannotDoThisOnAWednesday();
}
But how often is that likely?
I'd go with the default arguments, especially since C++ doesn't let you chain constructors (so you end up having to duplicate the initialiser list, and possibly more, for each overload).
That said, there are some gotchas with default arguments, including the fact that constants may be inlined (and thereby become part of your class' binary interface). Another to watch out for is that adding default arguments can turn an explicit multi-argument constructor into an implicit one-argument constructor:
class Vehicle {
public:
Vehicle(int wheels, std::string name = "Mini");
};
Vehicle x = 5; // this compiles just fine... did you really want it to?
__construct is a method for initializing of new object before it is used.
http://php.net/manual/en/language.oop5.decon.php#object.construct
Yes it can have a constructor and it is defined and behaves just like any other class's constructor. Except that abstract classes can't be directly instantiated, only extended, so the use is therefore always from a subclass's constructor.
Constructors are not inherited. They are called implicitly or explicitly by the child constructor.
The compiler creates a default constructor (one with no arguments) and a default copy constructor (one with an argument which is a reference to the same type). But if you want a constructor that will accept an int, you have to define it explicitly.
class A
{
public:
explicit A(int x) {}
};
class B: public A
{
public:
explicit B(int x) : A(x) { }
};
UPDATE: In C++11, constructors can be inherited. See Suma's answer for details.
I think you want something like this:
Intent foo = new Intent(this, viewContacts.class);
foo.putExtra("myFirstKey", "myFirstValue");
foo.putExtra("mySecondKey", "mySecondValue");
startActivity(foo);
or you can combine them into a bundle first. Corresponding getExtra() routines exist for the other side. See the intent topic in the dev guide for more information.
The constructor of PetStore
will call a constructor of Farm
; there's
no way you can prevent it. If you do nothing (as you've done), it will
call the default constructor (Farm()
); if you need to pass arguments,
you'll have to specify the base class in the initializer list:
PetStore::PetStore()
: Farm( neededArgument )
, idF( 0 )
{
}
(Similarly, the constructor of PetStore
will call the constructor of
nameF
. The constructor of a class always calls the constructors of
all of its base classes and all of its members.)
You're trying to create a ThingOne
by using operator=
which isn't going to work (incorrect syntax). Also, you're using a class name as a variable name, that is, ThingOne* ThingOne
. Firstly, let's fix the variable names:
private:
ThingOne* t1;
ThingTwo* t2;
Since these are pointers, they must point to something. If the object hasn't been constructed yet, you'll need to do so explicitly with new in your BigMommaClass
constructor:
BigMommaClass::BigMommaClass(int n1, int n2)
{
t1 = new ThingOne(100);
t2 = new ThingTwo(n1, n2);
}
Generally initializer lists are preferred for construction however, so it will look like:
BigMommaClass::BigMommaClass(int n1, int n2)
: t1(new ThingOne(100)), t2(new ThingTwo(n1, n2))
{ }
David's answer is correct. I'd like to add that you might be getting a sign from God that your design is messed up, and that "Son" ought not to be a subclass of "Super", but that, instead, Super has some implementation detail best expressed by having the functionality that Son provides, as a strategy of sorts.
EDIT: Jon Skeet's answer is awesomest.
You can create an array of pointers.
Car** mycars = new Car*[userInput];
for (int i=0; i<userInput; i++){
mycars[i] = new Car(...);
}
...
for (int i=0; i<userInput; i++){
delete mycars[i];
}
delete [] mycars;
or
Car() constructor does not need to be public. Add a static method to your class that builds an array:
static Car* makeArray(int length){
return new Car[length];
}
So, it is not stopping you from executing logic before the call to super. It is just stopping you from executing logic that you can't fit into a single expression.
Actually you can execute logic with several expessions, you just have to wrap your code in a static function and call it in the super statement.
Using your example:
public class MySubClassC extends MyClass {
public MySubClassC(Object item) {
// Create a list that contains the item, and pass the list to super
super(createList(item)); // OK
}
private static List createList(item) {
List list = new ArrayList();
list.add(item);
return list;
}
}
If you have a very complex class with a lot of options of which only some combinations are valid, consider using a Builder. Works very well both codewise but also logically.
The Builder is a nested class with methods only designed to set fields, and then the ComplexClass constructor only takes such a Builder as an argument.
Edit: The ComplexClass constructor can ensure that the state in the Builder is valid. This is very hard to do if you just use setters on ComplexClass.
What is usage of "Constructor Chain"?
You use it for calling one constructor from another constructor.
How can implement "Constructor Chain"?
Use ": this (yourProperties)" keyword after definition of constructor. for example:
Class MyBillClass
{
private DateTime requestDate;
private int requestCount;
public MyBillClass()
{
/// ===== we naming "a" constructor ===== ///
requestDate = DateTime.Now;
}
public MyBillClass(int inputCount) : this()
{
/// ===== we naming "b" constructor ===== ///
/// ===== This method is "Chained Method" ===== ///
this.requestCount= inputCount;
}
}
Why is it useful?
Important reason is reduce coding, and prevention of duplicate code. such as repeated code for initializing property
Suppose some property in class must be initialized with specific value (In our sample, requestDate). And class have 2 or more constructor. Without "Constructor Chain", you must repeat initializaion code in all constractors of class.
How it work? (Or, What is execution sequence in "Constructor Chain")?
in above example, method "a" will be executed first, and then instruction sequence will return to method "b".
In other word, above code is equal with below:
Class MyBillClass
{
private DateTime requestDate;
private int requestCount;
public MyBillClass()
{
/// ===== we naming "a" constructor ===== ///
requestDate = DateTime.Now;
}
public MyBillClass(int inputCount) : this()
{
/// ===== we naming "b" constructor ===== ///
// ===== This method is "Chained Method" ===== ///
/// *** --- > Compiler execute "MyBillClass()" first, And then continue instruction sequence from here
this.requestCount= inputCount;
}
}
Prefer initialization:
class C : public A
{
public:
C(const string &val) : A(anInt) {}
};
In C++11, you can use inheriting constructors (which has the syntax seen in your example D
).
Update: Inheriting Constructors have been available in GCC since version 4.8.
If you don't find initialization appealing (e.g. due to the number of possibilities in your actual case), then you might favor this approach for some TMP constructs:
class A
{
public:
A() {}
virtual ~A() {}
void init(int) { std::cout << "A\n"; }
};
class B : public A
{
public:
B() : A() {}
void init(int) { std::cout << "B\n"; }
};
class C : public A
{
public:
C() : A() {}
void init(int) { std::cout << "C\n"; }
};
class D : public A
{
public:
D() : A() {}
using A::init;
void init(const std::string& s) { std::cout << "D -> " << s << "\n"; }
};
int main()
{
B b; b.init(10);
C c; c.init(10);
D d; d.init(10); d.init("a");
return 0;
}
in visual studio 2012 or above, you can do like this
struct Foo { Foo(int x) { /* ... */ } };
struct Baz {
Foo foo[3];
Baz() : foo() { }
};
For Visual Studio 2017, press Ctrl + ..
Your constructor is expecting one parameter (data). You're not passing it in the call. I guess you wanted to initialise a field in the object. That would look like this:
class DHT:
def __init__(self):
self.data = {}
self.data['one'] = '1'
self.data['two'] = '2'
self.data['three'] = '3'
def showData(self):
print(self.data)
if __name__ == '__main__':
DHT().showData()
Or even just:
class DHT:
def __init__(self):
self.data = {'one': '1', 'two': '2', 'three': '3'}
def showData(self):
print(self.data)
A Java constructor has the same name as the name of the class to which it belongs.
Constructor’s syntax does not include a return type, since constructors never return a value.
Constructor is always called when object is created. example:- Default constructor
class Student3{
int id;
String name;
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student3 s1=new Student3();
Student3 s2=new Student3();
s1.display();
s2.display();
}
}
Output:
0 null
0 null
Explanation: In the above class,you are not creating any constructor so compiler provides you a default constructor.Here 0 and null values are provided by default constructor.
Example of parameterized constructor
In this example, we have created the constructor of Student class that have two parameters. We can have any number of parameters in the constructor.
class Student4{
int id;
String name;
Student4(int i,String n){
id = i;
name = n;
}
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student4 s1 = new Student4(111,"Karan");
Student4 s2 = new Student4(222,"Aryan");
s1.display();
s2.display();
}
}
Output:
111 Karan
222 Aryan
The two approaches are not interchangeable. You should initialize state in the constructor when using ES6 classes, and define the getInitialState
method when using React.createClass
.
See the official React doc on the subject of ES6 classes.
class MyComponent extends React.Component {
constructor(props) {
super(props);
this.state = { /* initial state */ };
}
}
is equivalent to
var MyComponent = React.createClass({
getInitialState() {
return { /* initial state */ };
},
});
For the example you gave, use default values:
class City:
def __init__(self, name="Default City Name"):
...
...
In general, you have two options:
1) Do if
-elif
blocks based on the type:
def __init__(self, name):
if isinstance(name, str):
...
elif isinstance(name, City):
...
...
2) Use duck typing --- that is, assume the user of your class is intelligent enough to use it correctly. This is typically the preferred option.
You're declaring a virtual
function and not defining it:
virtual void calculateCredits();
Either define it or declare it as:
virtual void calculateCredits() = 0;
Or simply:
virtual void calculateCredits() { };
Read more about vftable: http://en.wikipedia.org/wiki/Virtual_method_table
Two reasons for this:
1) Abstract classes have constructors
and those constructors are always invoked when a concrete subclass is instantiated. We know that when we are going to instantiate a class, we always use constructor of that class. Now every constructor invokes the constructor of its super class with an implicit call to super()
.
2) We know constructor are also used to initialize fields of a class. We also know that abstract classes may contain fields and sometimes they need to be initialized somehow by using constructor.
foo4
is initialised by default-constructing, copying and destroying a temporary object; usually, this is elided giving the same result as 3.Foo foo5
is a declaration, not an expression; function (and constructor) arguments must be expressions.Foo()
rather than the equivalent Foo::Foo()
(or indeed Foo::Foo::Foo::Foo::Foo()
)When do I use each?
Bar
from a temporary Foo
.Why and when would we create a static constructor ...?
One specific reason to use a static constructor is to create a 'super enum' class. Here's a (simple, contrived) example:
public class Animals
{
private readonly string _description;
private readonly string _speciesBinomialName;
public string Description { get { return _description; } }
public string SpeciesBinomialName { get { return _speciesBinomialName; } }
private Animals(string description, string speciesBinomialName)
{
_description = description;
_speciesBinomialName = speciesBinomialName;
}
private static readonly Animals _dog;
private static readonly Animals _cat;
private static readonly Animals _boaConstrictor;
public static Animals Dog { get { return _dog; } }
public static Animals Cat { get { return _cat; } }
public static Animals BoaConstrictor { get { return _boaConstrictor; } }
static Animals()
{
_dog = new Animals("Man's best friend", "Canis familiaris");
_cat = new Animals("Small, typically furry, killer", "Felis catus");
_boaConstrictor = new Animals("Large, heavy-bodied snake", "Boa constrictor");
}
}
You'd use it very similarly (in syntactical appearance) to any other enum:
Animals.Dog
The advantage of this over a regular enum
is that you can encapsulate related info easily. One disadvantage is that you can't use these values in a switch
statement (because it requires constant values).
A default constructor is created if you don't define any constructors in your class. It simply is a no argument constructor which does nothing. Edit: Except call super()
public Module(){
}
It's there to enforce some initialization logic required by all implementations of your abstract class, or any methods you have implemented on your abstract class (not all the methods on your abstract class have to be abstract, some can be implemented).
Any class which inherits from your abstract base class will be obliged to call the base constructor.
Object.create()
is a Javascript function which takes 2 arguments and returns a new object. const proto = {_x000D_
talk : () => console.log('hi')_x000D_
}_x000D_
_x000D_
const props = {_x000D_
age: {_x000D_
writable: true,_x000D_
configurable: true,_x000D_
value: 26_x000D_
}_x000D_
}_x000D_
_x000D_
_x000D_
let Person = Object.create(proto, props)_x000D_
_x000D_
console.log(Person.age);_x000D_
Person.talk();
_x000D_
new
keyword you have no control over this (however, you can overwrite them of course).new
keyword invokes a constructor function. With Object.create()
there is no need for invoking or even declaring a constructor function.A quick way to execute some time-consuming operation in any constructor is by creating an action and run them asynchronously.
new Action( async() => await InitializeThingsAsync())();
Running this piece of code will neither block your UI nor leave you with any loose threads. And if you need to update any UI (considering you are not using MVVM approach), you can use the Dispatcher to do so as many have suggested.
A Note: This option only provides you a way to start an execution of a method from the constructor if you don't have any init
or onload
or navigated
overrides. Most likely this will keep on running even after the construction has been completed. Hence the result of this method call may NOT be available in the constructor itself.
Assuming that Test is a class with a defined constructor, there's no difference. The latter form makes it a little clearer that Test's constructor is running, but that's about it.
How can I declare a class type, so that I ensure the object is a constructor of a general class?
A Constructor type could be defined as:
type AConstructorTypeOf<T> = new (...args:any[]) => T;
class A { ... }
function factory(Ctor: AConstructorTypeOf<A>){
return new Ctor();
}
const aInstance = factory(A);
Yes, a static class can have static constructor, and the use of this constructor is initialization of static member.
static class Employee1
{
static int EmpNo;
static Employee1()
{
EmpNo = 10;
// perform initialization here
}
public static void Add()
{
}
public static void Add1()
{
}
}
and static constructor get called only once when you have access any type member of static class with class name Class1
Suppose you are accessing the first EmployeeName field then constructor get called this time, after that it will not get called, even if you will access same type member.
Employee1.EmployeeName = "kumod";
Employee1.Add();
Employee1.Add();
In C++ there is a concept of constructor's initialization list, which is where you can and should call the base class' constructor and where you should also initialize the data members. The initialization list comes after the constructor signature following a colon, and before the body of the constructor. Let's say we have a class A:
class A : public B
{
public:
A(int a, int b, int c);
private:
int b_, c_;
};
Then, assuming B has a constructor which takes an int, A's constructor may look like this:
A::A(int a, int b, int c)
: B(a), b_(b), c_(c) // initialization list
{
// do something
}
As you can see, the constructor of the base class is called in the initialization list. Initializing the data members in the initialization list, by the way, is preferable to assigning the values for b_, and c_ inside the body of the constructor, because you are saving the extra cost of assignment.
Keep in mind, that data members are always initialized in the order in which they are declared in the class definition, regardless of their order in the initialization list. To avoid strange bugs, which may arise if your data members depend on each other, you should always make sure that the order of the members is the same in the initialization list and the class definition. For the same reason the base class constructor must be the first item in the initialization list. If you omit it altogether, then the default constructor for the base class will be called automatically. In that case, if the base class does not have a default constructor, you will get a compiler error.
As the other answers mention, a struct is basically treated as a class in C++. This allows you to have a constructor which can be used to initialise the struct with default values. Below, the constructor takes sz
and b
as arguments, and initializes the other variables to some default values.
struct blocknode
{
unsigned int bsize;
bool free;
unsigned char *bptr;
blocknode *next;
blocknode *prev;
blocknode(unsigned int sz, unsigned char *b, bool f = true,
blocknode *p = 0, blocknode *n = 0) :
bsize(sz), free(f), bptr(b), prev(p), next(n) {}
};
Usage:
unsigned char *bptr = new unsigned char[1024];
blocknode *fblock = new blocknode(1024, btpr);
An explicit call to a parent class constructor is required any time the parent class lacks a no-argument constructor. You can either add a no-argument constructor to the parent class or explicitly call the parent class constructor in your child class.
A much neater way to get 'alternate constructors' is to use classmethods. For instance:
>>> class MyData:
... def __init__(self, data):
... "Initialize MyData from a sequence"
... self.data = data
...
... @classmethod
... def fromfilename(cls, filename):
... "Initialize MyData from a file"
... data = open(filename).readlines()
... return cls(data)
...
... @classmethod
... def fromdict(cls, datadict):
... "Initialize MyData from a dict's items"
... return cls(datadict.items())
...
>>> MyData([1, 2, 3]).data
[1, 2, 3]
>>> MyData.fromfilename("/tmp/foobar").data
['foo\n', 'bar\n', 'baz\n']
>>> MyData.fromdict({"spam": "ham"}).data
[('spam', 'ham')]
The reason it's neater is that there is no doubt about what type is expected, and you aren't forced to guess at what the caller intended for you to do with the datatype it gave you. The problem with isinstance(x, basestring)
is that there is no way for the caller to tell you, for instance, that even though the type is not a basestring, you should treat it as a string (and not another sequence.) And perhaps the caller would like to use the same type for different purposes, sometimes as a single item, and sometimes as a sequence of items. Being explicit takes all doubt away and leads to more robust and clearer code.
the difference r
:
r
called explicitly while methods implicitaly.One should definitely prefer the solutions already posted, but since no one mentioned this solution yet, I think it is worth mentioning for completeness.
The @classmethod
approach can be modified to provide an alternative constructor which does not invoke the default constructor (__init__
). Instead, an instance is created using __new__
.
This could be used if the type of initialization cannot be selected based on the type of the constructor argument, and the constructors do not share code.
Example:
class MyClass(set):
def __init__(self, filename):
self._value = load_from_file(filename)
@classmethod
def from_somewhere(cls, somename):
obj = cls.__new__(cls) # Does not call __init__
super(MyClass, obj).__init__() # Don't forget to call any polymorphic base class initializers
obj._value = load_from_somewhere(somename)
return obj
#include <iostream>
class bar
{
public:
bar()
{
std::cout << "bar() called" << std::endl;
}
~bar()
{
std::cout << "~bar() called" << std::endl;
}
};
class foo
{
public:
foo()
: b(new bar())
{
std::cout << "foo() called" << std::endl;
throw "throw something";
}
~foo()
{
delete b;
std::cout << "~foo() called" << std::endl;
}
private:
bar *b;
};
int main(void)
{
try {
std::cout << "heap: new foo" << std::endl;
foo *f = new foo();
} catch (const char *e) {
std::cout << "heap exception: " << e << std::endl;
}
try {
std::cout << "stack: foo" << std::endl;
foo f;
} catch (const char *e) {
std::cout << "stack exception: " << e << std::endl;
}
return 0;
}
the output:
heap: new foo
bar() called
foo() called
heap exception: throw something
stack: foo
bar() called
foo() called
stack exception: throw something
the destructors are not called, so if a exception need to be thrown in a constructor, a lot of stuff(e.g. clean up?) to do.
Let's illustrate what's happening here:
Python 3.1.2 (r312:79147, Sep 27 2010, 09:45:41)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> class Foo:
... def __init__(self, x=[]):
... x.append(1)
...
>>> Foo.__init__.__defaults__
([],)
>>> f = Foo()
>>> Foo.__init__.__defaults__
([1],)
>>> f2 = Foo()
>>> Foo.__init__.__defaults__
([1, 1],)
You can see that the default arguments are stored in a tuple which is an attribute of the function in question. This actually has nothing to do with the class in question and goes for any function. In python 2, the attribute will be func.func_defaults
.
As other posters have pointed out, you probably want to use None
as a sentinel value and give each instance it's own list.
It is always a good coding practice to make your one argument constructors (including those with default values for arg2
,arg3
,...) as already stated.
Like always with C++: if you don't - you'll wish you did...
Another good practice for classes is to make copy construction and assignment private (a.k.a. disable it) unless you really need to implement it. This avoids having eventual copies of pointers when using the methods that C++ will create for you by default. An other way to do this is derive from boost::noncopyable
.
I am posting this as an answer because this is very important as of PHP 7.4.
The opcache.preload
mechanism of PHP 7.4 makes it possible to preload opcodes for classes. If you use it to preload a file that contains a class definition and some side effects, then classes defined in that file will "exist" for all subsequent scripts executed by this FPM server and its workers, but the side effects will not be in effect, and the autoloader will not require the file containing them because the class already "exists". This completely defeats any and all static initialization techniques that rely on executing top-level code in the file that contains the class definition.
The way to close resources are context managers, aka the with
statement:
class Foo(object):
def __init__(self):
self.bar = None
def __enter__(self):
if self.bar != 'open':
print 'opening the bar'
self.bar = 'open'
return self # this is bound to the `as` part
def close(self):
if self.bar != 'closed':
print 'closing the bar'
self.bar = 'close'
def __exit__(self, *err):
self.close()
if __name__ == '__main__':
with Foo() as foo:
print foo, foo.bar
output:
opening the bar
<__main__.Foo object at 0x17079d0> open
closing the bar
2) Python's objects get deleted when their reference count is 0. In your example the del foo
removes the last reference so __del__
is called instantly. The GC has no part in this.
class Foo(object):
def __del__(self):
print "deling", self
if __name__ == '__main__':
import gc
gc.disable() # no gc
f = Foo()
print "before"
del f # f gets deleted right away
print "after"
output:
before
deling <__main__.Foo object at 0xc49690>
after
The gc
has nothing to do with deleting your and most other objects. It's there to clean up when simple reference counting does not work, because of self-references or circular references:
class Foo(object):
def __init__(self, other=None):
# make a circular reference
self.link = other
if other is not None:
other.link = self
def __del__(self):
print "deling", self
if __name__ == '__main__':
import gc
gc.disable()
f = Foo(Foo())
print "before"
del f # nothing gets deleted here
print "after"
gc.collect()
print gc.garbage # The GC knows the two Foos are garbage, but won't delete
# them because they have a __del__ method
print "after gc"
# break up the cycle and delete the reference from gc.garbage
del gc.garbage[0].link, gc.garbage[:]
print "done"
output:
before
after
[<__main__.Foo object at 0x22ed8d0>, <__main__.Foo object at 0x22ed950>]
after gc
deling <__main__.Foo object at 0x22ed950>
deling <__main__.Foo object at 0x22ed8d0>
done
3) Lets see:
class Foo(object):
def __init__(self):
raise Exception
def __del__(self):
print "deling", self
if __name__ == '__main__':
f = Foo()
gives:
Traceback (most recent call last):
File "asd.py", line 10, in <module>
f = Foo()
File "asd.py", line 4, in __init__
raise Exception
Exception
deling <__main__.Foo object at 0xa3a910>
Objects are created with __new__
then passed to __init__
as self
. After a exception in __init__
, the object will typically not have a name (ie the f =
part isn't run) so their ref count is 0. This means that the object is deleted normally and __del__
is called.
Well, from time to time I run into the same question. As far as I know, one cannot do that when one wants to add dynamic parameters to the constructor. However, the factory pattern may help.
public interface MyBean {
// here be my fancy stuff
}
public interface MyBeanFactory {
public MyBean getMyBean(/* bean parameters */);
}
@Component
public class MyBeanFactoryImpl implements MyBeanFactory {
@Autowired
WhateverIWantToInject somethingInjected;
public MyBean getMyBean(/* params */) {
return new MyBeanImpl(/* params */);
}
private class MyBeanImpl implements MyBean {
public MyBeanImpl(/* params */) {
// let's do whatever one has to
}
}
}
@Component
public class MyConsumerClass {
@Autowired
private MyBeanFactory beanFactory;
public void myMethod() {
// here one has to prepare the parameters
MyBean bean = beanFactory.getMyBean(/* params */);
}
}
Now, MyBean
is not a spring bean per se, but it is close enough. Dependency Injection works, although I inject the factory and not the bean itself - one has to inject a new factory on top of his own new MyBean
implementation if one wants to replace it.
Further, MyBean
has access to other beans - because it may have access to the factory's autowired stuff.
And one might apparently want to add some logic to the getMyBean
function, which is extra effort I allow, but unfortunately I have no better solution. Since the problem usually is that the dynamic parameters come from an external source, like a database, or user interaction, therefore I must instantiate that bean only in mid-run, only when that info is readily available, so the Factory
should be quite adequate.
That is not possible, but you can add an anonymous initializer like this:
final int anInt = ...;
Object a = new Class1()
{
{
System.out.println(anInt);
}
void someNewMethod() {
}
};
Don't forget final on declarations of local variables or parameters used by the anonymous class, as i did it for anInt.
You need to specify what are the class invariants, i.e. properties which will always be true for an instance of the class (for example, the title of a book will never be null, or the size of a dog will always be > 0).
These invariants should be established during construction, and be preserved along the lifetime of the object, which means that methods shall not break the invariants. The constructors can set these invariants either by having compulsory arguments, or by setting default values:
class Book {
private String title; // not nullable
private String isbn; // nullable
// Here we provide a default value, but we could also skip the
// parameterless constructor entirely, to force users of the class to
// provide a title
public Book()
{
this("Untitled");
}
public Book(String title) throws IllegalArgumentException
{
if (title == null)
throw new IllegalArgumentException("Book title can't be null");
this.title = title;
// leave isbn without value
}
// Constructor with title and isbn
}
However, the choice of these invariants highly depends on the class you're writing, how you'll use it, etc., so there's no definitive answer to your question.
Why not this way:
Public Sub Init(myArguments)
instead of Private Sub Class_Initialize()
Dim myInstance As New myClass: myInstance.Init myArguments
You can use a constructor with no parameters in your Parent class :
public parent() { }
The first allocates an object with automatic storage duration, which means it will be destructed automatically upon exit from the scope in which it is defined.
The second allocated an object with dynamic storage duration, which means it will not be destructed until you explicitly use delete
to do so.
You could use super(ChildClass, self).__init__()
class BaseClass(object):
def __init__(self, *args, **kwargs):
pass
class ChildClass(BaseClass):
def __init__(self, *args, **kwargs):
super(ChildClass, self).__init__(*args, **kwargs)
Your indentation is incorrect, here's the modified code:
class Car(object):
condition = "new"
def __init__(self, model, color, mpg):
self.model = model
self.color = color
self.mpg = mpg
class ElectricCar(Car):
def __init__(self, battery_type, model, color, mpg):
self.battery_type=battery_type
super(ElectricCar, self).__init__(model, color, mpg)
car = ElectricCar('battery', 'ford', 'golden', 10)
print car.__dict__
Here's the output:
{'color': 'golden', 'mpg': 10, 'model': 'ford', 'battery_type': 'battery'}
Second approach is object initializer in C#
Object initializers let you assign values to any accessible fields or properties of an object at creation time without having to explicitly invoke a constructor.
The first approach
var albumData = new Album("Albumius", "Artistus", 2013);
explicitly calls the constructor, whereas in second approach constructor call is implicit. With object initializer you can leave out some properties as well. Like:
var albumData = new Album
{
Name = "Albumius",
};
Object initializer would translate into something like:
var albumData;
var temp = new Album();
temp.Name = "Albumius";
temp.Artist = "Artistus";
temp.Year = 2013;
albumData = temp;
Why it uses a temporary object (in debug mode) is answered here by Jon Skeet.
As far as advantages for both approaches are concerned, IMO, object initializer would be easier to use specially if you don't want to initialize all the fields. As far as performance difference is concerned, I don't think there would any since object initializer calls the parameter less constructor and then assign the properties. Even if there is going to be performance difference it should be negligible.
I was having some issues using the above solutions with an "associative array" type object. These solutions seem to preserve the values, but they do not preserve the actual names of the objects that those values are associated with, which can cause some issues. So I put together the following functions which I am using instead:
function flattenAssocArr(object) {
if(typeof object == "object") {
var keys = [];
keys[0] = "ASSOCARR";
keys.push(...Object.keys(object));
var outArr = [];
outArr[0] = keys;
for(var i = 1; i < keys.length; i++) {
outArr[i] = flattenAssocArr(object[keys[i]])
}
return outArr;
} else {
return object;
}
}
function expandAssocArr(object) {
if(typeof object !== "object")
return object;
var keys = object[0];
var newObj = new Object();
if(keys[0] === "ASSOCARR") {
for(var i = 1; i < keys.length; i++) {
newObj[keys[i]] = expandAssocArr(object[i])
}
}
return newObj;
}
Note that these can't be used with any arbitrary object -- basically it creates a new array, stores the keys as element 0, with the data following it. So if you try to load an array that isn't created with these functions having element 0 as a key list, the results might be...interesting :)
I'm using it like this:
var objAsString = JSON.stringify(flattenAssocArr(globalDataset));
var strAsObject = expandAssocArr(JSON.parse(objAsString));
This is not only a 'newbie' scenario. I just ran across this compiler message (GCC 5.4) when refactoring a class to remove some constructor parameters. I forgot to update both the declaration and definition, and the compiler spit out this unintuitive error.
The bottom line seems to be this: If the compiler can't match the definition's signature to the declaration's signature it thinks the definition is not a constructor and then doesn't know how to parse the code and displays this error. Which is also what happened for the OP: std::string
is not the same type as string
so the declaration's signature differed from the definition's and this message was spit out.
As a side note, it would be nice if the compiler looked for almost-matching constructor signatures and upon finding one suggested that the parameters didn't match rather than giving this message.
Yes, they can throw exceptions. If so, they will only be partially initialized and if non-final, subject to attack.
The following is from the Secure Coding Guidelines 2.0.
Partially initialized instances of a non-final class can be accessed via a finalizer attack. The attacker overrides the protected finalize method in a subclass, and attempts to create a new instance of that subclass. This attempt fails (in the above example, the SecurityManager check in ClassLoader's constructor throws a security exception), but the attacker simply ignores any exception and waits for the virtual machine to perform finalization on the partially initialized object. When that occurs the malicious finalize method implementation is invoked, giving the attacker access to this, a reference to the object being finalized. Although the object is only partially initialized, the attacker can still invoke methods on it (thereby circumventing the SecurityManager check).
You can simply write :
class A(object):
def __init__(self):
print "Initialiser A was called"
class B(A):
def __init__(self):
A.__init__(self)
# A.__init__(self,<parameters>) if you want to call with parameters
print "Initialiser B was called"
class C(B):
def __init__(self):
# A.__init__(self) # if you want to call most super class...
B.__init__(self)
print "Initialiser C was called"
As has already been shown here, there are many ways of declaring multiple
constructors in PHP, but none of them are the correct
way of doing so (since PHP technically doesn't allow it).
But it doesn't stop us from hacking this functionality...
Here's another example:
<?php
class myClass {
public function __construct() {
$get_arguments = func_get_args();
$number_of_arguments = func_num_args();
if (method_exists($this, $method_name = '__construct'.$number_of_arguments)) {
call_user_func_array(array($this, $method_name), $get_arguments);
}
}
public function __construct1($argument1) {
echo 'constructor with 1 parameter ' . $argument1 . "\n";
}
public function __construct2($argument1, $argument2) {
echo 'constructor with 2 parameter ' . $argument1 . ' ' . $argument2 . "\n";
}
public function __construct3($argument1, $argument2, $argument3) {
echo 'constructor with 3 parameter ' . $argument1 . ' ' . $argument2 . ' ' . $argument3 . "\n";
}
}
$object1 = new myClass('BUET');
$object2 = new myClass('BUET', 'is');
$object3 = new myClass('BUET', 'is', 'Best.');
Source: The easiest way to use and understand multiple constructors:
Hope this helps. :)
As has been pointed out, the objects are created base-down upon construction. When the base object is being constructed, the derived object does not exist yet, so a virtual function override cannot work.
However, this can be solved with polymorphic getters that use static polymorphism instead of virtual functions if your getters return constants, or otherwise can be expressed in a static member function, This example uses CRTP (https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern).
template<typename DerivedClass>
class Base
{
public:
inline Base() :
foo(DerivedClass::getFoo())
{}
inline int fooSq() {
return foo * foo;
}
const int foo;
};
class A : public Base<A>
{
public:
inline static int getFoo() { return 1; }
};
class B : public Base<B>
{
public:
inline static int getFoo() { return 2; }
};
class C : public Base<C>
{
public:
inline static int getFoo() { return 3; }
};
int main()
{
A a;
B b;
C c;
std::cout << a.fooSq() << ", " << b.fooSq() << ", " << c.fooSq() << std::endl;
return 0;
}
With the use of static polymorphism, the base class knows which class' getter to call as the information is provided at compile-time.
In my case I was using the prototype name as the object name. For e.g.
function proto1()
{}
var proto1 = new proto1();
It was a silly mistake but might be of help to someone like me ;)
you don't.
the constructor is part of the class that can implement an interface. The interface is just a contract of methods the class must implement.
Constructors are not normal methods and they cannot be "overridden". Saying that a constructor can be overridden would imply that a superclass constructor would be visible and could be called to create an instance of a subclass. This isn't true... a subclass doesn't have any constructors by default (except a no-arg constructor if the class it extends has one). It has to explicitly declare any other constructors, and those constructors belong to it and not to its superclass, even if they take the same parameters that the superclass constructors take.
The stuff you mention about default no arg constructors is just an aspect of how constructors work and has nothing to do with overriding.
You could do this:
class C
{
public:
template <typename T> C(T*);
};
template <typename T> T* UseType()
{
static_cast<T*>(nullptr);
}
Then to create an object of type C
using int
as the template parameter to the constructor:
C obj(UseType<int>());
Since you can't pass template parameters to a constructor, this solution essentially converts the template parameter to a regular parameter. Using the UseType<T>()
function when calling the constructor makes it clear to someone looking at the code that the purpose of that parameter is to tell the constructor what type to use.
One use case for this would be if the constructor creates a derived class object and assigns it to a member variable that is a base class pointer. (The constructor needs to know which derived class to use, but the class itself doesn't need to be templated since the same base class pointer type is always used.)
This is very easy to understand if you track class and instance dictionaries.
class C:
one = 42
def __init__(self,val):
self.two=val
ci=C(50)
print(ci.__dict__)
print(C.__dict__)
The result will be like this:
{'two': 50}
{'__module__': '__main__', 'one': 42, '__init__': <function C.__init__ at 0x00000213069BF6A8>, '__dict__': <attribute '__dict__' of 'C' objects>, '__weakref__': <attribute '__weakref__' of 'C' objects>, '__doc__': None}
Note I set the full results in here but what is important that the instance ci
dict will be just {'two': 50}
, and class dictionary will have the 'one': 42
key value pair inside.
This is all you should know about that specific variables.
You forgot the return types in your member function definitions:
int ttTree::ttTreeInsert(int value) { ... }
^^^
and so on.
Virtual functions basically provide polymorphic behavior. That is, when you work with an object whose dynamic type is different than the static (compile time) type with which it is referred to, it provides behavior that is appropriate for the actual type of object instead of the static type of the object.
Now try to apply that sort of behavior to a constructor. When you construct an object the static type is always the same as the actual object type since:
To construct an object, a constructor needs the exact type of the object it is to create [...] Furthermore [...]you cannot have a pointer to a constructor
(Bjarne Stroustup (P424 The C++ Programming Language SE))
C++11: Yes!
C++11 and onwards has this same feature (called delegating constructors).
The syntax is slightly different from C#:
class Foo {
public:
Foo(char x, int y) {}
Foo(int y) : Foo('a', y) {}
};
C++03: No
Unfortunately, there's no way to do this in C++03, but there are two ways of simulating this:
You can combine two (or more) constructors via default parameters:
class Foo {
public:
Foo(char x, int y=0); // combines two constructors (char) and (char, int)
// ...
};
Use an init method to share common code:
class Foo {
public:
Foo(char x);
Foo(char x, int y);
// ...
private:
void init(char x, int y);
};
Foo::Foo(char x)
{
init(x, int(x) + 7);
// ...
}
Foo::Foo(char x, int y)
{
init(x, y);
// ...
}
void Foo::init(char x, int y)
{
// ...
}
See the C++FAQ entry for reference.
Collection literals were scheduled for Java 7, but didn't make it in. So nothing automatic yet.
You can use guava's Sets
:
Sets.newHashSet("a", "b", "c")
Or you can use the following syntax, which will create an anonymous class, but it's hacky:
Set<String> h = new HashSet<String>() {{
add("a");
add("b");
}};
There are some equivalents of constructors for when the zero values can't make sensible default values or for when some parameter is necessary for the struct initialization.
Supposing you have a struct like this :
type Thing struct {
Name string
Num int
}
then, if the zero values aren't fitting, you would typically construct an instance with a NewThing
function returning a pointer :
func NewThing(someParameter string) *Thing {
p := new(Thing)
p.Name = someParameter
p.Num = 33 // <- a very sensible default value
return p
}
When your struct is simple enough, you can use this condensed construct :
func NewThing(someParameter string) *Thing {
return &Thing{someParameter, 33}
}
If you don't want to return a pointer, then a practice is to call the function makeThing
instead of NewThing
:
func makeThing(name string) Thing {
return Thing{name, 33}
}
Reference : Allocation with new in Effective Go.
class Grandpa
{
public function __construct()
{}
}
class Papa extends Grandpa
{
public function __construct()
{
//call Grandpa's constructor
parent::__construct();
}
}
class Kiddo extends Papa
{
public function __construct()
{
//this is not a bug, it works that way in php
Grandpa::__construct();
}
}
I'm not familiar with the async keyword (is this specific to Silverlight or a new feature in the beta version of Visual Studio?), but I think I can give you an idea of why you can't do this.
If I do:
var o = new MyObject();
MessageBox(o.SomeProperty.ToString());
o may not be done initializing before the next line of code runs. An instantiation of your object cannot be assigned until your constructor is completed, and making the constructor asynchronous wouldn't change that so what would be the point? However, you could call an asynchronous method from your constructor and then your constructor could complete and you would get your instantiation while the async method is still doing whatever it needs to do to setup your object.
Beware of blindly following Resharper's advice and making the class sealed! If it's a model in EF Code First it will remove the virtual keyword and that would disable lazy loading of it's relationships.
public **virtual** User User{ get; set; }
From react docs Passing arguments to event handlers
<button onClick={(e) => this.deleteRow(id, e)}>Delete Row</button>
<button onClick={this.deleteRow.bind(this, id)}>Delete Row</button>
Why do you want to do that?
However, You can do this:
public void foo(int param1)
{
int param2 = 2;
// rest of code
}
or:
public void foo(int param1, int param2)
{
// rest of code
}
public void foo(int param1)
{
foo(param1, 2);
}
Superclass constructor CAN'T be inherited in extended class. Although it can be invoked in extended class constructor's with super() as the first statement.
Issue Log: App Not Setup. This app is still in development mode. and you dont have access to it. register test user or ask an app admin for permission
HOW TO CHANGE TO LIVE MODE
1. go to : https://developers.facebook.com
2. select your app on "My Apps" List
3. toggle the switch from OFF to ON
HOW TO ADD AS TEST OR ADMIN
1. go to : https://developers.facebook.com
2. select your app on "My Apps" List
3. go to : Roles > Roles > Press Add for example administrator
4. Search your new admin/tester Facebook account.
5. admin must enter facebook password to confirm.then submit
the new admin must go to developer.facebook page and accept the request
6. go to : https://developers.facebook.com
7. Profile > Requests > Confirm
8. Congratulation you have been assign as new Admin
HOW TO GET AND SET HASHKEY FOR DEVELOPMENT
as Refer to Facebook Login Documentation
https://developers.facebook.com/docs/android/getting-started/#create_hash
The most preferable solution by me is by code ( Troubleshooting Sample Apps )
it will print out the hash key. you can update it on
https://developers.facebook.com/apps/yourFacebookappID/settings/basic/
on Android > Key Hashes section
a step by step process on how to get the hashKey.
step by step process on how Update on Facebook Developer.
Open Facebook Developer Page. You need access as to update the Facebook Developer page.
https://developers.facebook.com
if you want your check box to keep its height and width but only be invisible:
.hiddenCheckBox{
visibility: hidden;
}
if you want your check box to be invisible without any with and height:
.hiddenCheckBox{
display: none;
}
You can use the position:fixed;
, but without set left
and top
. Then you will push it to the right using margin-left
, to position it in the right position you wish.
Check a demo here: http://jsbin.com/icili5
"_blank" is not guaranteed to be a new tab or window. It's implemented differently per-browser.
You can, however, put anything into target. I usually just say "_tab", and every browser I know of just opens it in a new tab.
Be aware that it means it's a named target, so if you try to open 2 URLs, they will use the same tab.
Or add "sort name" to list alphabetically
Get-ADPrincipalGroupMembership username | select name | sort name
Edit : After Android Studios 1.5 android support Vector Asset Studio.
Follow this, which says:
To start Vector Asset Studio:
- In Android Studio, open an Android app project.
- In the Project window, select the Android view.
- Right-click the res folder and select New > Vector Asset.
Go to Settings > Plugin > Browse Repository > Search Android Drawable Import
This plugin consists of 4 main features.
How to Use Material Icons Drawable Import : (Android Studio 1.2)
With something like this:
String mDrawableName = "myappicon";
int resID = getResources().getIdentifier(mDrawableName , "drawable", getPackageName());
When you run make, add VERBOSE=1
to see the full command output. For example:
cmake .
make VERBOSE=1
Or you can add -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON
to the cmake command for permanent verbose command output from the generated Makefiles.
cmake -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON .
make
To reduce some possibly less-interesting output you might like to use the following options. The option CMAKE_RULE_MESSAGES=OFF
removes lines like [ 33%] Building C object..., while --no-print-directory
tells make to not print out the current directory filtering out lines like make[1]: Entering directory
and make[1]: Leaving directory
.
cmake -DCMAKE_RULE_MESSAGES:BOOL=OFF -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON .
make --no-print-directory
you cannot access array (php array) from js try
<?php
$array = array(1,2,3,4,5,6);
echo json_encode($array);
?>
and js
$(document).ready( function() {
$('#prev').click(function() {
$.ajax({
type: 'POST',
url: 'ajax.php',
data: 'id=testdata',
dataType: 'json',
cache: false,
success: function(result) {
$('#content1').html(result[0]);
},
});
});
});
You can use the compareTo() method from Java Date class
public int result = date.compareTo(Date anotherDate);
Return Value: The function gives three return values specified below:
It returns the value 0 if the argument Date is equal to this Date. It returns a value less than 0 if this Date is before the Date argument. It returns a value greater than 0 if this Date is after the Date argument.
I needed the rotateAroundWorldAxis
function but the above code doesn't work with the newest release (r52). It looks like getRotationFromMatrix()
was replaced by setEulerFromRotationMatrix()
function rotateAroundWorldAxis( object, axis, radians ) {
var rotationMatrix = new THREE.Matrix4();
rotationMatrix.makeRotationAxis( axis.normalize(), radians );
rotationMatrix.multiplySelf( object.matrix ); // pre-multiply
object.matrix = rotationMatrix;
object.rotation.setEulerFromRotationMatrix( object.matrix );
}
If you want a window as a whole to have a specific size, you can just give it the size you want with the geometry
command. That's really all you need to do.
For example:
mw.geometry("500x500")
Though, you'll also want to make sure that the widgets inside the window resize properly, so change how you add the frame to this:
back.pack(fill="both", expand=True)
My solutions in one of my own sites, with a table:
$.getJSON("sections/view_numbers_update.php", function(data) {
$.each(data, function(index, objNumber) {
$('#tr_' + objNumber.intID).find("td").eq(3).html(objNumber.datLastCalled);
$('#tr_' + objNumber.intID).find("td").eq(4).html(objNumber.strStatus);
$('#tr_' + objNumber.intID).find("td").eq(5).html(objNumber.intDuration);
$('#tr_' + objNumber.intID).find("td").eq(6).html(objNumber.blnWasHuman);
});
});
sections/view_numbers_update.php Returns something like:
[{"intID":"19","datLastCalled":"Thu, 10 Jan 13 08:52:20 +0000","strStatus":"Completed","intDuration":"0:04 secs","blnWasHuman":"Yes","datModified":1357807940},
{"intID":"22","datLastCalled":"Thu, 10 Jan 13 08:54:43 +0000","strStatus":"Completed","intDuration":"0:00 secs","blnWasHuman":"Yes","datModified":1357808079}]
HTML table:
<table id="table_numbers">
<tr>
<th>[...]</th>
<th>[...]</th>
<th>[...]</th>
<th>Last Call</th>
<th>Status</th>
<th>Duration</th>
<th>Human?</th>
<th>[...]</th>
</tr>
<tr id="tr_123456">
[...]
</tr>
</table>
This essentially gives every row a unique id preceding with 'tr_' to allow for other numbered element ids, at server script time. The jQuery script then just gets this TR_[id] element, and fills the correct indexed cell with the json return.
The advantage is you could get the complete array from the DB, and either foreach($array as $record) to create the table html, OR (if there is an update request) you can die(json_encode($array)) before displaying the table, all in the same page, but same display code.
Using $('#myDiv').click(function(){
is better as it follows standard event registration model. (jQuery internally uses addEventListener
and attachEvent
).
Basically registering an event in modern way is the unobtrusive way of handling events. Also to register more than one event listener for the target you can call addEventListener()
for the same target.
var myEl = document.getElementById('myelement');
myEl.addEventListener('click', function() {
alert('Hello world');
}, false);
myEl.addEventListener('click', function() {
alert('Hello world again!!!');
}, false);
Why use addEventListener? (From MDN)
addEventListener is the way to register an event listener as specified in W3C DOM. Its benefits are as follows:
- It allows adding more than a single handler for an event. This is particularly useful for DHTML libraries or Mozilla extensions that need to work well even if other libraries/extensions are used.
- It gives you finer-grained control of the phase when the listener gets activated (capturing vs. bubbling)
- It works on any DOM element, not just HTML elements.
More about Modern event registration -> http://www.quirksmode.org/js/events_advanced.html
Other methods such as setting the HTML attributes, example:
<button onclick="alert('Hello world!')">
Or DOM element properties, example:
myEl.onclick = function(event){alert('Hello world');};
are old and they can be over written easily.
HTML attribute should be avoided as It makes the markup bigger and less readable. Concerns of content/structure and behavior are not well-separated, making a bug harder to find.
The problem with the DOM element properties method is that only one event handler can be bound to an element per event.
More about Traditional event handling -> http://www.quirksmode.org/js/events_tradmod.html
MDN Reference: https://developer.mozilla.org/en-US/docs/DOM/event
You are also able to test slow internet connectivity on an real android device:
Tested with Samsung Galaxy S8 + Android 8.0.0
Go to Settings -> Connection -> Mobile Network -> and under networkmode you can choose to only use 2G or 3G connections
Objects, which are also called instances, are self-contained elements of a program with related features and data. For the most part, you use the class merely to create instances and then work with those instances.
-Definition taken from the book "Sams Teach Yourself Java in 21 days".
Say you have 2 Classes, public class MainClass and public class Class_2 and you want to make an instance of Class_2 in MainClass.
This is a very simple and basic way to do it:
public MainClass() /*******this is the constructor of MainClass*******/
{
Class_2 nameyouwant = new Class_2();
}
I hope this helps!
[[ $var =~ ^-?[0-9]+$ ]]
^
indicates the beginning of the input pattern-
is a literal "-"?
means "0 or 1 of the preceding (-
)"+
means "1 or more of the preceding ([0-9]
)"$
indicates the end of the input patternSo the regex matches an optional -
(for the case of negative numbers), followed by one or more decimal digits.
References:
Looks like there are no direct way to do this to detect if user has tapped on home + power button
. As per this, it was possible earlier by using darwin notification, but it doesn't work any more. Since snapchat is already doing it, my guess is that they are checking the iPhone photo album to detect if there is a new picture got added in between this 10 seconds, and in someway they are comparing with the current image displayed. May be some image processing is done for this comparison. Just a thought, probably you can try to expand this to make it work. Check this for more details.
Edit:
Looks like they might be detecting the UITouch cancel event(Screen capture cancels touches) and showing this error message to the user as per this blog: How to detect screenshots on iOS (like SnapChat)
In that case you can use – touchesCancelled:withEvent:
method to sense the UITouch cancellation to detect this. You can remove the image in this delegate method and show an appropriate alert to the user.
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesCancelled:touches withEvent:event];
NSLog(@"Touches cancelled");
[self.imageView removeFromSuperView]; //and show an alert to the user
}
Actually I think that more general approach to loop through dictionary is to use iteritems():
# get tuples of term, courses
for term, term_courses in courses.iteritems():
# get tuples of course number, info
for course, info in term_courses.iteritems():
# loop through info
for k, v in info.iteritems():
print k, v
output:
assistant Peter C.
prereq cs101
...
name Programming a Robotic Car
teacher Sebastian
Or, as Matthias mentioned in comments, if you don't need keys, you can just use itervalues():
for term_courses in courses.itervalues():
for info in term_courses.itervalues():
for k, v in info.iteritems():
print k, v
Kill is definitly the wrong way! The PID will stay, Replicationsjobs will be killed etc. etc.
STOP MySQL Server
/sbin/service mysql stop
START MySQL Server
/sbin/service mysql start
RESTART MySQL Server
/sbin/service mysql restart
Perhaps sudo will be needed if you have not enough rights
try
.insertAfter()
here
$(content).insertAfter('#bla');
There is a JQuery plug-in that accomplishes pretty much what you're trying to do: https://github.com/mgalante/jquery.redirect/blob/master/jquery.redirect.js.
After including JQuery and the jquery.redirect.min.js plug-in, you can simply do something like this:
$().redirect('demo.php', {'arg1': 'value1', 'arg2': 'value2'});
Use the following code on newer JQuery versions instead:
$.redirect('demo.php', {'arg1': 'value1', 'arg2': 'value2'});
Hope this helps!
You can use the following
new java.sql.Timestamp(System.currentTimeMillis()).getTime()
Result : 1539594988651
Hope this will help. Just my suggestion and not for reward points.
The top answer is equivalent to doing:
let text = find.reduce((acc, item, i) => {
const regex = new RegExp(item, "g");
return acc.replace(regex, replace[i]);
}, textarea);
Given this:
var textarea = $(this).val();
var find = ["<", ">", "\n"];
var replace = ["<", ">", "<br/>"];
In this case, no imperative programming is going on.
try this one, it might be helpful for you
String arr= "[1,2]";
int[] arr=Stream.of(str.replaceAll("[\\[\\]\\, ]", "").split("")).mapToInt(Integer::parseInt).toArray();
You can start by installing the below given command in the conda environment:
conda install pip
Followed by installing all pip packages you need in the environment.
After installing all the conda and pip packages to export the environment use:
conda env export -n <env-name> > environment.yml
This will create the required file in the folder
add typing.d.ts in main folder of the application and over there declare the varible which you want to use every time
declare var System: any;
declare var require: any;
after declaring this in typing.d.ts, error for require will not come in the application..
for further investigation: print out the mssql error message:
$dbhandle = mssql_connect($myServer, $myUser, $myPass) or die("Could not connect to database: ".mssql_get_last_message());
It is also important to specify the port: On MS SQL Server 2000, separate it with a comma:
$myServer = "10.85.80.229:1443";
or
$myServer = "10.85.80.229,1443";
Refer this:
@RequestMapping(value="download", method=RequestMethod.GET)
public void getDownload(HttpServletResponse response) {
// Get your file stream from wherever.
InputStream myStream = someClass.returnFile();
// Set the content type and attachment header.
response.addHeader("Content-disposition", "attachment;filename=myfilename.txt");
response.setContentType("txt/plain");
// Copy the stream to the response's output stream.
IOUtils.copy(myStream, response.getOutputStream());
response.flushBuffer();
}
The problem is in your playerMovement
method. You are creating the string name of your room variables (ID1
, ID2
, ID3
):
letsago = "ID" + str(self.dirDesc.values())
However, what you create is just a str
. It is not the variable. Plus, I do not think it is doing what you think its doing:
>>>str({'a':1}.values())
'dict_values([1])'
If you REALLY needed to find the variable this way, you could use the eval
function:
>>>foo = 'Hello World!'
>>>eval('foo')
'Hello World!'
or the globals
function:
class Foo(object):
def __init__(self):
super(Foo, self).__init__()
def test(self, name):
print(globals()[name])
foo = Foo()
bar = 'Hello World!'
foo.text('bar')
However, instead I would strongly recommend you rethink you class(es). Your userInterface
class is essentially a Room
. It shouldn't handle player movement. This should be within another class, maybe GameManager
or something like that.
Standardize your module's imports and exports then you won't risk hitting problems with misspelled property names.
module.exports = Component
should become export default Component
.
CommonJS uses module.exports
as a convention, however, this means that you are just working with a regular Javascript object and you are able to set the value of any key you want (whether that's exports
, exoprts
or exprots
). There are no runtime or compile-time checks to tell you that you've messed up.
If you use ES6 (ES2015) syntax instead, then you are working with syntax and keywords. If you accidentally type exoprt default Component
then it will give you a compile error to let you know.
In your case, you can simplify the Speaker component.
import React from 'react';
export default React.createClass({
render() {
return (
<h1>Speaker</h1>
)
}
});
The approved solution doesn't work in my case, so my solution is the following one:
''' The column name in the example case is "Unnamed: 7"
but it works with any other name ("Unnamed: 0" for example). '''
df.rename({"Unnamed: 7":"a"}, axis="columns", inplace=True)
# Then, drop the column as usual.
df.drop(["a"], axis=1, inplace=True)
Hope it helps others.
Your code concatenates three strings, then converts the result to a number.
You need to convert each variable to a number by calling parseFloat()
around each one.
total = parseFloat(myInt1) + parseFloat(myInt2) + parseFloat(myInt3);
I had the same problem. I have tried three ways that were usually suggested:
none if which solved my problem. I am using godaddy and came across a suggested solution which was:
Voila! Now you have a different max upload file size :)
A lot of people seem to be looking for this answer. I found it buried in an answer to another question here: Syncing column width of between tables in two different frames, etc
Of the dozens of methods I have tried this is the only method I found that works reliably to allow you to have a scrolling bottom table with the header table having the same widths.
Here is how I did it, first I improved upon the jsfiddle above to create this function, which works on both td
and th
(in case that trips up others who use th
for styling of their header rows).
var setHeaderTableWidth= function (headertableid,basetableid) {
$("#"+headertableid).width($("#"+basetableid).width());
$("#"+headertableid+" tr th").each(function (i) {
$(this).width($($("#"+basetableid+" tr:first td")[i]).width());
});
$("#" + headertableid + " tr td").each(function (i) {
$(this).width($($("#" + basetableid + " tr:first td")[i]).width());
});
}
Next, you need to create two tables, NOTE the header table should have an extra TD
to leave room in the top table for the scrollbar, like this:
<table id="headertable1" class="input-cells table-striped">
<thead>
<tr style="background-color:darkgray;color:white;"><th>header1</th><th>header2</th><th>header3</th><th>header4</th><th>header5</th><th>header6</th><th></th></tr>
</thead>
</table>
<div id="resizeToBottom" style="overflow-y:scroll;overflow-x:hidden;">
<table id="basetable1" class="input-cells table-striped">
<tbody >
<tr>
<td>testdata</td>
<td>2</td>
<td>3</td>
<td>4</span></td>
<td>55555555555555</td>
<td>test</td></tr>
</tbody>
</table>
</div>
Then do something like:
setHeaderTableWidth('headertable1', 'basetable1');
$(window).resize(function () {
setHeaderTableWidth('headertable1', 'basetable1');
});
This is the only solution that I found on Stack Overflow that works out of many similar questions that have been posted, that works in all my cases.
For example, I tried the jQuery stickytables plugin which does not work with durandal, and the Google Code project here https://code.google.com/p/js-scroll-table-header/issues/detail?id=2
Other solutions involving cloning the tables, have poor performance, or suck and don't work in all cases.
There is no need for these overly complex solutions. Just make two tables like the examples below and call setHeaderTableWidth function like described here and boom, you are done.
If this does not work for you, you probably were playing with your CSS box-sizing property and you need to set it correctly. It is easy to screw up your CSS content by accident. There are many things that can go wrong, so just be aware/careful of that. This approach works for me.
This code will be helpful for you
Model.update({
'type': "newuser"
}, {
$set: {
email: "[email protected]",
phoneNumber:"0123456789"
}
}, {
multi: true
},
function(err, result) {
console.log(result);
console.log(err);
})
This borrows from a few other answers here but I thought it might help someone. If you define the following function on your custom object, then you have a factory function that you can pass a generic object into and it will return for you an instance of the class.
CustomObject.create = function (obj) {
var field = new CustomObject();
for (var prop in obj) {
if (field.hasOwnProperty(prop)) {
field[prop] = obj[prop];
}
}
return field;
}
Use like this
var typedObj = CustomObject.create(genericObj);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(ContextCompat.getColor(ctx, android.R.color.transparent)));
private Date getStartOfDay(Date date) {
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DATE);
calendar.setTimeInMillis(0);
calendar.set(year, month, day, 0, 0, 0);
return calendar.getTime();
}
private Date getEndOfDay(Date date) {
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DATE);
calendar.setTimeInMillis(0);
calendar.set(year, month, day, 23, 59, 59);
return calendar.getTime();
}
calendar.setTimeInMillis(0); gives you accuracy upto milliseconds
You should give an object as argument
userModel.count({name: "sam"});
or
userModel.count({name: "sam"}).exec(); //if you are using promise
or
userModel.count({}); // if you want to get all counts irrespective of the fields
On the recent version of mongoose, count() is deprecated so use
userModel.countDocuments({name: "sam"});
According to this snippet here, this approach should be good for long strings:
private string StringToHex(string hexstring)
{
StringBuilder sb = new StringBuilder();
foreach (char t in hexstring)
{
//Note: X for upper, x for lower case letters
sb.Append(Convert.ToInt32(t).ToString("x"));
}
return sb.ToString();
}
usage:
string result = StringToHex("Hello world"); //returns "48656c6c6f20776f726c64"
Another approach in one line
string input = "Hello world";
string result = String.Concat(input.Select(x => ((int)x).ToString("x")));
There is a simple way for @Sprunth's answer.
private void GetAllDiskDrives()
{
var searcher = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive");
foreach (ManagementObject wmi_HD in searcher.Get())
{
HardDrive hd = new HardDrive();
hd.Model = wmi_HD["Model"].ToString();
hd.InterfaceType = wmi_HD["InterfaceType"].ToString();
hd.Caption = wmi_HD["Caption"].ToString();
hd.SerialNo =wmi_HD.GetPropertyValue("SerialNumber").ToString();//get the serailNumber of diskdrive
hdCollection.Add(hd);
}
}
public class HardDrive
{
public string Model { get; set; }
public string InterfaceType { get; set; }
public string Caption { get; set; }
public string SerialNo { get; set; }
}
And if you neither want to use @Autowire nor injecting @Value you can simply do (with fallback included):
System.getProperty("spring.profiles.active", "unknown");
This will return any active profile (or fallback to 'unknown').
This may work for you, try it and see if it works:
<input type="image" src="/library/graphics/cecb2.gif">
just use this at the end of your button click event
protected void btnAddButton_Click(object sender, EventArgs e)
{
... save data routin
Response.Redirect(Request.Url.AbsoluteUri);
}
The Provider piece must be Provider=Microsoft.ACE.OLEDB.12.0
if your target database is ACCDB format. Provider=Microsoft.Jet.OLEDB.4.0
only works for the older MDB format.
You shouldn't even need Access installed if you're running 32 bit Windows. Jet 4 is included as part of the operating system. If you're using 64 bit Windows, Jet 4 is not included, but you still wouldn't need Access itself installed. You can install the Microsoft Access Database Engine 2010 Redistributable. Make sure to download the matching version (AccessDatabaseEngine.exe for 32 bit Windows, or AccessDatabaseEngine_x64.exe for 64 bit).
You can avoid the issue about which ADO version reference by using late binding, which doesn't require any reference.
Dim conn As Object
Set conn = CreateObject("ADODB.Connection")
Then assign your ConnectionString property to the conn object. Here is a quick example which runs from a code module in Excel 2003 and displays a message box with the row count for MyTable. It uses late binding for the ADO connection and recordset objects, so doesn't require setting a reference.
Public Sub foo()
Dim cn As Object
Dim rs As Object
Dim strSql As String
Dim strConnection As String
Set cn = CreateObject("ADODB.Connection")
strConnection = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:\Access\webforums\whiteboard2003.mdb"
strSql = "SELECT Count(*) FROM MyTable;"
cn.Open strConnection
Set rs = cn.Execute(strSql)
MsgBox rs.fields(0) & " rows in MyTable"
rs.Close
Set rs = Nothing
cn.Close
Set cn = Nothing
End Sub
If this answer doesn't resolve the problem, edit your question to show us the full connection string you're trying to use and the exact error message you get in response for that connection string.
WHERE cast(timestamp as date) = '2012-05-05'
To be able to create a relation, the table Storage Engine must be InnoDB. You can edit in Operations tab.
Then, you need to be sure that the id column in your main table has been indexed. It should appear at Index section in Structure tab.
Finally, you could see the option Relations View in Structure tab. When edditing, you will be able to select the parent column in foreign table to create the relation.
See attachments. I hope this could be useful for anyone.
It's wrong because (in the absence of a read error) it enters the loop one more time than the author expects. If there is a read error, the loop never terminates.
Consider the following code:
/* WARNING: demonstration of bad coding technique!! */
#include <stdio.h>
#include <stdlib.h>
FILE *Fopen(const char *path, const char *mode);
int main(int argc, char **argv)
{
FILE *in;
unsigned count;
in = argc > 1 ? Fopen(argv[1], "r") : stdin;
count = 0;
/* WARNING: this is a bug */
while( !feof(in) ) { /* This is WRONG! */
fgetc(in);
count++;
}
printf("Number of characters read: %u\n", count);
return EXIT_SUCCESS;
}
FILE * Fopen(const char *path, const char *mode)
{
FILE *f = fopen(path, mode);
if( f == NULL ) {
perror(path);
exit(EXIT_FAILURE);
}
return f;
}
This program will consistently print one greater than the number of characters in the input stream (assuming no read errors). Consider the case where the input stream is empty:
$ ./a.out < /dev/null
Number of characters read: 1
In this case, feof()
is called before any data has been read, so it returns false. The loop is entered, fgetc()
is called (and returns EOF
), and count is incremented. Then feof()
is called and returns true, causing the loop to abort.
This happens in all such cases. feof()
does not return true until after a read on the stream encounters the end of file. The purpose of feof()
is NOT to check if the next read will reach the end of file. The purpose of feof()
is to determine the status of a previous read function
and distinguish between an error condition and the end of the data stream. If fread()
returns 0, you must use feof
/ferror
to decide whether an error occurred or if all of the data was consumed. Similarly if fgetc
returns EOF
. feof()
is only useful after fread has returned zero or fgetc
has returned EOF
. Before that happens, feof()
will always return 0.
It is always necessary to check the return value of a read (either an fread()
, or an fscanf()
, or an fgetc()
) before calling feof()
.
Even worse, consider the case where a read error occurs. In that case, fgetc()
returns EOF
, feof()
returns false, and the loop never terminates. In all cases where while(!feof(p))
is used, there must be at least a check inside the loop for ferror()
, or at the very least the while condition should be replaced with while(!feof(p) && !ferror(p))
or there is a very real possibility of an infinite loop, probably spewing all sorts of garbage as invalid data is being processed.
So, in summary, although I cannot state with certainty that there is never a situation in which it may be semantically correct to write "while(!feof(f))
" (although there must be another check inside the loop with a break to avoid a infinite loop on a read error), it is the case that it is almost certainly always wrong. And even if a case ever arose where it would be correct, it is so idiomatically wrong that it would not be the right way to write the code. Anyone seeing that code should immediately hesitate and say, "that's a bug". And possibly slap the author (unless the author is your boss in which case discretion is advised.)
In my case, none of the approaches listed worked. I finally downloaded Rapid Environment Editor (ver 8).
It showed that my additions to the user environment variables weren't present. When I added them with REE, everything worked immediately.
(Running Windows 8.1)
Do the following, download SQLLite Database Browser from here:
Locate your db. file in your phone.
Then, as soon you install the program go to: "Browse Data", you will see all the SMS there!!
You can actually export the data to an excel file or SQL.
To anyone with this problem in the future, the reason is because the status code was a 404 (or in my case was a 500). It appears the InpuStream
function will throw an error when the status code is not 200.
In my case I control my own server and was returning a 500 status code to indicate an error occurred. Despite me also sending a body with a string message detailing the error, the inputstream
threw an error regardless of the body being completely readable.
If you control your server I suppose this can be handled by sending yourself a 200 status code and then handling whatever the string error response was.
The complement of a regular language is also a regular language, but to construct it you have to build the DFA for the regular language, and make any valid state change into an error. See this for an example. What the page doesn't say is that it converted /(ac|bd)/
into /(a[^c]?|b[^d]?|[^ab])/
. The conversion from a DFA back to a regular expression is not trivial. It is easier if you can use the regular expression unchanged and change the semantics in code, like suggested before.
list1 = (x[0] for x in source_list)
list2 = (x[1] for x in source_list)
Try this:
Go to virtual box > right click the OS > settings > under one of the many tab that I don't remember(sorry for this, i dont have vbox installed)> locate the VDI (virtual box disk image) file..
and save the settings.. then try to start the OS..
You can index into a string in C# like an array, and you get the character at that index.
Example:
In Java, you would say
str.charAt(8);
In C#, you would say
str[8];
Is there difference in defining Id & name in ApplicationContext xml ? No As of 3.1(spring), id is also defined as an xsd:string type. It means whatever characters allowed in defining name are also allowed in Id. This was not possible prior to Spring 3.1.
Why to use name when it is same as Id ? It is useful for some situations, such as allowing each component in an application to refer to a common dependency by using a bean name that is specific to that component itself.
For example, the configuration metadata for subsystem A may refer to a DataSource via the name subsystemA-dataSource. The configuration metadata for subsystem B may refer to a DataSource via the name subsystemB-dataSource. When composing the main application that uses both these subsystems the main application refers to the DataSource via the name myApp-dataSource. To have all three names refer to the same object you add to the MyApp configuration metadata the following
<bean id="myApp-dataSource" name="subsystemA-dataSource,subsystemB-dataSource" ..../>
Alternatively, You can have separate xml configuration files for each sub-system and then you can make use of
alias to define your own names.
<alias name="subsystemA-dataSource" alias="subsystemB-dataSource"/>
<alias name="subsystemA-dataSource" alias="myApp-dataSource" />
The DisplayHtml(string html) recommended by m3z worked for me.
In case it helps somebody, I would also like to mention that initially there were some spaces in my HTML that invalidated the HTML and so the text appeared as a string. The spaces were introduced (around the angular brackets) when I pasted the HTML into Visual Studio. So if your text is still appearing as text after you try the solutions mentioned in this post, then it may be worth checking that the HTML syntax is correct.
Just another possible solution I found having the same error message.
When trying to setup a .NET 4.0 web application to a new applicition pool I was receiving this strange error telling me it was trying to process my aspx file with the static file handler, which didn't make sense.
For some reason the ISAPI for .NET 4.0 was set to disabled in the ISAPI and CGI Restrictions area of the server level in the IIS manager. Setting it to enabled was all that was required, however the IIS 7.5 manager is so convoluted and hard to follow it took me a long time to figure this out.
I'm guessing that since it was a 4.0 Application that could not be processed by the 4.0 Engine the static file handler was being used by default.
Ok, finally found the solution.
Probably due to lack of experience with ReactJS and web development...
var Task = React.createClass({
render: function() {
var percentage = this.props.children + '%';
....
<div className="ui-progressbar-value ui-widget-header ui-corner-left" style={{width : percentage}}/>
...
I created the percentage variable outside in the render function.
Entity Framework Ver 6 (Alpha, rc1) has something called Custom Conventions. To set decimal precision:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Properties<decimal>().Configure(config => config.HasPrecision(18, 4));
}
Reference:
C99 does, if you have
#include <stdbool.h>
If the compiler does not support C99, you can define it yourself:
// file : myboolean.h
#ifndef MYBOOLEAN_H
#define MYBOOLEAN_H
#define false 0
#define true 1
typedef int bool; // or #define bool int
#endif
(but note that this definition changes ABI for bool
type so linking against external libraries which were compiled with properly defined bool
may cause hard-to-diagnose runtime errors).
Please see http://java.dzone.com/articles/how-debug-remote-java-applicat to enable the remote debugging. If you are using tomcat to run your application, start tomcat with remote debug parameters or you can start tomcat with JPDA support by using following command.
Windows
<tomcat bin dir>/startup.bat jpda
*nix
<tomcat bin dir>/startup.sh jpda
this will enable remote debugging on port 8000
$order = new WC_Order( $post_id );
If you
echo $order->id;
then you'll be returned the id of the post from which the order is made. As you've already got that, it's probably not what you want.
echo $order->get_order_number();
will return the id of the order (with a # in front of it). To get rid of the #,
echo trim( str_replace( '#', '', $order->get_order_number() ) );
as per the accepted answer.
But why stop with MessageBox-specific implementation? Use the class below like this:
private void OnFormClosing(object sender, FormClosingEventArgs e)
{
DialogResult dg;
using (DialogCenteringService centeringService = new DialogCenteringService(this)) // center message box
{
dg = MessageBox.Show(this, "Are you sure?", "Confirm exit", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
}
if (dg == DialogResult.No)
{
e.Cancel = true;
}
}
The code that you can use with anything that shows dialog windows, even if they're owned by another thread (our app has multiple UI threads):
(Here is the updated code which takes monitor working areas into account, so that the dialog isn't centered between two monitors or is partly off-screen. With it you'll need enum SetWindowPosFlags
, which is below)
public class DialogCenteringService : IDisposable
{
private readonly IWin32Window owner;
private readonly HookProc hookProc;
private readonly IntPtr hHook = IntPtr.Zero;
public DialogCenteringService(IWin32Window owner)
{
if (owner == null) throw new ArgumentNullException("owner");
this.owner = owner;
hookProc = DialogHookProc;
hHook = SetWindowsHookEx(WH_CALLWNDPROCRET, hookProc, IntPtr.Zero, GetCurrentThreadId());
}
private IntPtr DialogHookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode < 0)
{
return CallNextHookEx(hHook, nCode, wParam, lParam);
}
CWPRETSTRUCT msg = (CWPRETSTRUCT)Marshal.PtrToStructure(lParam, typeof(CWPRETSTRUCT));
IntPtr hook = hHook;
if (msg.message == (int)CbtHookAction.HCBT_ACTIVATE)
{
try
{
CenterWindow(msg.hwnd);
}
finally
{
UnhookWindowsHookEx(hHook);
}
}
return CallNextHookEx(hook, nCode, wParam, lParam);
}
public void Dispose()
{
UnhookWindowsHookEx(hHook);
}
private void CenterWindow(IntPtr hChildWnd)
{
Rectangle recChild = new Rectangle(0, 0, 0, 0);
bool success = GetWindowRect(hChildWnd, ref recChild);
if (!success)
{
return;
}
int width = recChild.Width - recChild.X;
int height = recChild.Height - recChild.Y;
Rectangle recParent = new Rectangle(0, 0, 0, 0);
success = GetWindowRect(owner.Handle, ref recParent);
if (!success)
{
return;
}
Point ptCenter = new Point(0, 0);
ptCenter.X = recParent.X + ((recParent.Width - recParent.X) / 2);
ptCenter.Y = recParent.Y + ((recParent.Height - recParent.Y) / 2);
Point ptStart = new Point(0, 0);
ptStart.X = (ptCenter.X - (width / 2));
ptStart.Y = (ptCenter.Y - (height / 2));
//MoveWindow(hChildWnd, ptStart.X, ptStart.Y, width, height, false);
Task.Factory.StartNew(() => SetWindowPos(hChildWnd, (IntPtr)0, ptStart.X, ptStart.Y, width, height, SetWindowPosFlags.SWP_ASYNCWINDOWPOS | SetWindowPosFlags.SWP_NOSIZE | SetWindowPosFlags.SWP_NOACTIVATE | SetWindowPosFlags.SWP_NOOWNERZORDER | SetWindowPosFlags.SWP_NOZORDER));
}
// some p/invoke
// ReSharper disable InconsistentNaming
public delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);
public delegate void TimerProc(IntPtr hWnd, uint uMsg, UIntPtr nIDEvent, uint dwTime);
private const int WH_CALLWNDPROCRET = 12;
// ReSharper disable EnumUnderlyingTypeIsInt
private enum CbtHookAction : int
// ReSharper restore EnumUnderlyingTypeIsInt
{
// ReSharper disable UnusedMember.Local
HCBT_MOVESIZE = 0,
HCBT_MINMAX = 1,
HCBT_QS = 2,
HCBT_CREATEWND = 3,
HCBT_DESTROYWND = 4,
HCBT_ACTIVATE = 5,
HCBT_CLICKSKIPPED = 6,
HCBT_KEYSKIPPED = 7,
HCBT_SYSCOMMAND = 8,
HCBT_SETFOCUS = 9
// ReSharper restore UnusedMember.Local
}
[DllImport("kernel32.dll")]
static extern int GetCurrentThreadId();
[DllImport("user32.dll")]
private static extern bool GetWindowRect(IntPtr hWnd, ref Rectangle lpRect);
[DllImport("user32.dll")]
private static extern int MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, SetWindowPosFlags uFlags);
[DllImport("User32.dll")]
public static extern UIntPtr SetTimer(IntPtr hWnd, UIntPtr nIDEvent, uint uElapse, TimerProc lpTimerFunc);
[DllImport("User32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll")]
public static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
[DllImport("user32.dll")]
public static extern int UnhookWindowsHookEx(IntPtr idHook);
[DllImport("user32.dll")]
public static extern IntPtr CallNextHookEx(IntPtr idHook, int nCode, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll")]
public static extern int GetWindowTextLength(IntPtr hWnd);
[DllImport("user32.dll")]
public static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int maxLength);
[DllImport("user32.dll")]
public static extern int EndDialog(IntPtr hDlg, IntPtr nResult);
[StructLayout(LayoutKind.Sequential)]
public struct CWPRETSTRUCT
{
public IntPtr lResult;
public IntPtr lParam;
public IntPtr wParam;
public uint message;
public IntPtr hwnd;
};
// ReSharper restore InconsistentNaming
}
[Flags]
public enum SetWindowPosFlags : uint
{
// ReSharper disable InconsistentNaming
/// <summary>
/// If the calling thread and the thread that owns the window are attached to different input queues, the system posts the request to the thread that owns the window. This prevents the calling thread from blocking its execution while other threads process the request.
/// </summary>
SWP_ASYNCWINDOWPOS = 0x4000,
/// <summary>
/// Prevents generation of the WM_SYNCPAINT message.
/// </summary>
SWP_DEFERERASE = 0x2000,
/// <summary>
/// Draws a frame (defined in the window's class description) around the window.
/// </summary>
SWP_DRAWFRAME = 0x0020,
/// <summary>
/// Applies new frame styles set using the SetWindowLong function. Sends a WM_NCCALCSIZE message to the window, even if the window's size is not being changed. If this flag is not specified, WM_NCCALCSIZE is sent only when the window's size is being changed.
/// </summary>
SWP_FRAMECHANGED = 0x0020,
/// <summary>
/// Hides the window.
/// </summary>
SWP_HIDEWINDOW = 0x0080,
/// <summary>
/// Does not activate the window. If this flag is not set, the window is activated and moved to the top of either the topmost or non-topmost group (depending on the setting of the hWndInsertAfter parameter).
/// </summary>
SWP_NOACTIVATE = 0x0010,
/// <summary>
/// Discards the entire contents of the client area. If this flag is not specified, the valid contents of the client area are saved and copied back into the client area after the window is sized or repositioned.
/// </summary>
SWP_NOCOPYBITS = 0x0100,
/// <summary>
/// Retains the current position (ignores X and Y parameters).
/// </summary>
SWP_NOMOVE = 0x0002,
/// <summary>
/// Does not change the owner window's position in the Z order.
/// </summary>
SWP_NOOWNERZORDER = 0x0200,
/// <summary>
/// Does not redraw changes. If this flag is set, no repainting of any kind occurs. This applies to the client area, the nonclient area (including the title bar and scroll bars), and any part of the parent window uncovered as a result of the window being moved. When this flag is set, the application must explicitly invalidate or redraw any parts of the window and parent window that need redrawing.
/// </summary>
SWP_NOREDRAW = 0x0008,
/// <summary>
/// Same as the SWP_NOOWNERZORDER flag.
/// </summary>
SWP_NOREPOSITION = 0x0200,
/// <summary>
/// Prevents the window from receiving the WM_WINDOWPOSCHANGING message.
/// </summary>
SWP_NOSENDCHANGING = 0x0400,
/// <summary>
/// Retains the current size (ignores the cx and cy parameters).
/// </summary>
SWP_NOSIZE = 0x0001,
/// <summary>
/// Retains the current Z order (ignores the hWndInsertAfter parameter).
/// </summary>
SWP_NOZORDER = 0x0004,
/// <summary>
/// Displays the window.
/// </summary>
SWP_SHOWWINDOW = 0x0040,
// ReSharper restore InconsistentNaming
}
If you are using this line:
sessionFactory.getHibernateProperties().put("hibernate.dialect", env.getProperty("hibernate.dialect"));
make sure that env.getProperty("hibernate.dialect")
is not null.
You can use the getName()
method of FragmentManager.BackStackEntry
which was introduced in API level 14. This method will return a tag which was the one you used when you added the Fragment to the backstack with addTobackStack(tag)
.
int index = getActivity().getFragmentManager().getBackStackEntryCount() - 1
FragmentManager.BackStackEntry backEntry = getFragmentManager().getBackStackEntryAt(index);
String tag = backEntry.getName();
Fragment fragment = getFragmentManager().findFragmentByTag(tag);
You need to make sure that you added the fragment to the backstack like this:
fragmentTransaction.addToBackStack(tag);
Might want to check out jQuery Timer to manage one or multiple timers.
http://code.google.com/p/jquery-timer/
var timer = $.timer(yourfunction, 10000);
function yourfunction() { alert('test'); }
Then you can control it with:
timer.play();
timer.pause();
timer.toggle();
timer.once();
etc...
UPDATE: this only tested with server side rendering ( universal Javascript ) here is my boilerplate.
With only file-loader you can load images dynamically - the trick is to use ES6 template strings so that Webpack can pick it up:
This will NOT work. :
const myImg = './cute.jpg'
<img src={require(myImg)} />
To fix this, just use template strings instead :
const myImg = './cute.jpg'
<img src={require(`${myImg}`)} />
webpack.config.js :
var HtmlWebpackPlugin = require('html-webpack-plugin')
var ExtractTextWebpackPlugin = require('extract-text-webpack-plugin')
module.exports = {
entry : './src/app.js',
output : {
path : './dist',
filename : 'app.bundle.js'
},
plugins : [
new ExtractTextWebpackPlugin('app.bundle.css')],
module : {
rules : [{
test : /\.css$/,
use : ExtractTextWebpackPlugin.extract({
fallback : 'style-loader',
use: 'css-loader'
})
},{
test: /\.js$/,
exclude: /(node_modules)/,
loader: 'babel-loader',
query: {
presets: ['react','es2015']
}
},{
test : /\.jpg$/,
exclude: /(node_modules)/,
loader : 'file-loader'
}]
}
}
I know this post is a year old, but I'd like to provide a different solution approach to those who have a similar issue:
The jQuery change event is used only on user input fields because if anything else is manipulated (e.g., a div), that manipulation is coming from code. So, find where the manipulation occurs, and then add whatever you need to there.
But if that's not possible for any reason (you're using a complicated plugin or can't find any "callback" possibilities) then the jQuery approach I'd suggest is:
a. For simple DOM manipulation, use jQuery chaining and traversing, $("#content").html('something').end().find(whatever)....
b. If you'd like to do something else, employ jQuery's bind
with custom event and triggerHandler
$("#content").html('something').triggerHandler('customAction');
$('#content').unbind().bind('customAction', function(event, data) {
//Custom-action
});
Here's a link to jQuery trigger handler: http://api.jquery.com/triggerHandler/
$("#DDLID").val( $("#DDLID option:first-child").val() );
Add the following lines to the files ~/.bashrc
and ~/.bash_profile
:
# NVM changes
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
and restart the terminal or do source ~/.bashrc
or source ~/.bash_profile
. If you need command completion for nvm then also add the line:
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"
Along with the above lines to ~/.bashrc
and ~/.bash_profile
.
The underlying problem is Ctrl+Alt+Left and Right are used by window managers to switch workspace and/or OEM utilities to change the screen orientation.
You can change the assignments using
File / Settings / Keymap
then Main Menu / Navigate
find Back
and Forward
and right click to Add Keyboard Shortcut
to set an alternative key chord.
Alt Graph+Left and Alt Graph+Right works well for me (IDEA 13.1.4 on Ubuntu under IceWM).
Another trick not yet mentioned is to have the class which implements a property (e.g. Foo
of type Bar
) also define a delegate delegate void ActByRef<T1,T2>(ref T1 p1, ref T2 p2);
and implement a method ActOnFoo<TX1>(ref Bar it, ActByRef<Bar,TX1> proc, ref TX1 extraParam1)
(and possibly versions for two and three "extra parameters" as well) which will pass its internal representation of Foo
to the supplied procedure as a ref
parameter. This has a couple of big advantages over other methods of working with the property:
Passing things be ref
is an excellent pattern; too bad it's not used more.
For lists, use contains
:
[1,2,3].contains(1) == true
same issue with KAV. Restart it solved the pb.
Well, not always. Using cookies, you are good. But the "can I safely rely on the id being present" urged me to extend the discussion with an important point (mostly for reference, as the visitor count of this page seems quite high).
PHP can be configured to maintain sessions by URL-rewriting, instead of cookies. (How it's good or bad (<-- see e.g. the topmost comment there) is a separate question, let's now stick to the current one, with just one side-note: the most prominent issue with URL-based sessions -- the blatant visibility of the naked session ID -- is not an issue with internal Ajax calls; but then, if it's turned on for Ajax, it's turned on for the rest of the site, too, so there...)
In case of URL-rewriting (cookieless) sessions, Ajax calls must take care of it themselves that their request URLs are properly crafted. (Or you can roll your own custom solution. You can even resort to maintaining sessions on the client side, in less demanding cases.) The point is the explicit care needed for session continuity, if not using cookies:
If the Ajax calls just extract URLs verbatim from the HTML (as received from PHP), that should be OK, as they are already cooked (umm, cookified).
If they need to assemble request URIs themselves, the session ID needs to be added to the URL manually. (Check here, or the page sources generated by PHP (with URL-rewriting on) to see how to do it.)
From OWASP.org:
Effectively, the web application can use both mechanisms, cookies or URL parameters, or even switch from one to the other (automatic URL rewriting) if certain conditions are met (for example, the existence of web clients without cookies support or when cookies are not accepted due to user privacy concerns).
From a Ruby-forum post:
When using php with cookies, the session ID will automatically be sent in the request headers even for Ajax XMLHttpRequests. If you use or allow URL-based php sessions, you'll have to add the session id to every Ajax request url.
A simple JavaScript function will do the job.
function ClearFields() {
document.getElementById("textfield1").value = "";
document.getElementById("textfield2").value = "";
}
And just have your button call it:
<button type="button" onclick="ClearFields();">Clear</button>
With appFuse framework, you can create an Spring MVC archetype with jpa support, etc ...
Take a look at it's quickStart guide to see how to create an archetype based on this Framework.
Foundational frameworks in AppFuse:
For example to create an appFuse light archetype :
mvn archetype:generate -B -DarchetypeGroupId=org.appfuse.archetypes
-DarchetypeArtifactId=appfuse-light-struts-archetype -DarchetypeVersion=2.2.1
-DgroupId=com.mycompany -DartifactId=myproject
While @Eli is quite correct that there usually isn't much of a need to do it, it is possible. savefig
takes a bbox_inches
argument that can be used to selectively save only a portion of a figure to an image.
Here's a quick example:
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
# Make an example plot with two subplots...
fig = plt.figure()
ax1 = fig.add_subplot(2,1,1)
ax1.plot(range(10), 'b-')
ax2 = fig.add_subplot(2,1,2)
ax2.plot(range(20), 'r^')
# Save the full figure...
fig.savefig('full_figure.png')
# Save just the portion _inside_ the second axis's boundaries
extent = ax2.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
fig.savefig('ax2_figure.png', bbox_inches=extent)
# Pad the saved area by 10% in the x-direction and 20% in the y-direction
fig.savefig('ax2_figure_expanded.png', bbox_inches=extent.expanded(1.1, 1.2))
The full figure:
Area inside the second subplot:
Area around the second subplot padded by 10% in the x-direction and 20% in the y-direction:
1-make a search in your local drive and type "php.ini" 2-you may see many files named php.ini you should choose the one that fits with your php version (see localhost) 3-open the php.ini file make a search on "max_execution_time" then make it equal to "-1" to make it unlimited
For bootstrap 4 just add this class:
w-100
Yes, but the syntax is different than what you have
SELECT
<fields>
FROM
<table1>
LEFT JOIN <table2>
ON <criteria for join>
AND <other criteria for join>
LEFT JOIN <table3>
ON <criteria for join>
AND <other criteria for join>
You should install PDO on your server.
Edit your php.ini (look at your phpinfo()
, "Loaded Configuration File" line, to find the php.ini file path).
Find and uncomment the following line (remove the ;
character):
;extension=pdo_mysql.so
Then, restart your Apache server. For more information, please read the documentation.
You can access the namespace's dictionary with vars():
>>> import argparse
>>> args = argparse.Namespace()
>>> args.foo = 1
>>> args.bar = [1,2,3]
>>> d = vars(args)
>>> d
{'foo': 1, 'bar': [1, 2, 3]}
You can modify the dictionary directly if you wish:
>>> d['baz'] = 'store me'
>>> args.baz
'store me'
Yes, it is okay to access the __dict__ attribute. It is a well-defined, tested, and guaranteed behavior.
Update:
if (localStorage.hasOwnProperty("username")) {
//
}
Another way, relevant when value is not expected to be empty string, null or any other falsy value:
if (localStorage["username"]) {
//
}
Take a look at toggle()
jQuery function :
Also, innerHTML
jQuery Function is .html()
.
If you have a string, parse it as an integer:
var num = '20.536';
var result = parseInt(num, 10); // 20
If you have a number, ECMAScript 6 offers Math.trunc
for completely consistent truncation, already available in Firefox 24+ and Edge:
var num = -2147483649.536;
var result = Math.trunc(num); // -2147483649
If you can’t rely on that and will always have a positive number, you can of course just use Math.floor
:
var num = 20.536;
var result = Math.floor(num); // 20
And finally, if you have a number in [−2147483648, 2147483647], you can truncate to 32 bits using any bitwise operator. | 0
is common, and >>> 0
can be used to obtain an unsigned 32-bit integer:
var num = -20.536;
var result = num | 0; // -20
This works fine .. here btnAddCat is button id
$('#btnAddCat').click(function(){
var eventCategory=$("input[name=txtCategory]").val();
alert(eventCategory);
});
Try this:
Select Project_Name, ReleaseDate, TaskName
From DB_Table
Where Project_Name like '{?Pm-?Proj_Name}'
And ReleaseDate >= currentdate
currentdate should be a valid database function or field to work. If you are using MS SQL Server, use GETDATE() instead.
If all you want is to filter records in a subreport based on a parameter from the main report, it might be easier to simply add the table to the subreport, and then create a Project_Name link between the main report and subreport. You can then use the Select Expert to filter the ReleaseDate as well.
File name should match the layout id which in this example is : items_list_item.xml in the layout folder of your application
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
>
<ImageView android:id="@+id/R.id.list_item_image"
android:layout_width="100dip"
android:layout_height="wrap_content" />
</LinearLayout>
I think the best way to do is the way mentioned by @Salvador Dali. Not that the others are wrong.
Because when you have a data set where you just want to select one column and put it into one variable and the rest of the columns into another for comparison or computational purposes. Then dropping the column of the data set might not help. Of course there are use cases for that as well.
x_cols = [x for x in data.columns if x != 'name of column to be excluded']
Then you can put those collection of columns in variable x_cols
into another variable like x_cols1
for other computation.
ex: x_cols1 = data[x_cols]
Use join
:
>>> sentence = ['this', 'is', 'a', 'sentence']
>>> '-'.join(sentence)
'this-is-a-sentence'
>>> ' '.join(sentence)
'this is a sentence'
The best solution I have found is in the blog post Using Newer Version(s) of .NET with PowerShell. This allows powershell.exe to run with .NET 4 assemblies.
Simply modify (or create) $pshome\powershell.exe.config
so that it contains the following:
<?xml version="1.0"?>
<configuration>
<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedRuntime version="v4.0.30319"/>
<supportedRuntime version="v2.0.50727"/>
</startup>
</configuration>
Additional, quick setup notes:
Locations and files are somewhat platform dependent; however will give you an inline gist of how to make the solution work for you.
cd $pshome
in the Powershell window (doesn't work from DOS prompt).
C:\Windows\System32\WindowsPowerShell\v1.0\
powershell.exe.config
if your PowerShell.exe
is being executed (create the config file if need be).
PowerShellISE.Exe
is running then you need to create its companion config file as PowerShellISE.Exe.config
I think you have to write some extra code. For example:
if 'MICHAEL89' in map(lambda name: name.upper(), USERNAMES):
...
In this case we are forming a new list with all entries in USERNAMES
converted to upper case and then comparing against this new list.
Update
As @viraptor says, it is even better to use a generator instead of map
. See @Nathon's answer.
Adding to what @KyleMit said, consider using:
col-md-*
classes for the larger outer columnscol-xs-*
classes for the smaller inner columnsThis will be useful when you view the page on different screen sizes.
On a small screen, the wrapping of larger outer columns will then happen while maintaining the smaller inner columns, if possible
setup.py is designed to be run from the command line. You'll need to open your command prompt (In Windows 7, hold down shift while right-clicking in the directory with the setup.py file. You should be able to select "Open Command Window Here").
From the command line, you can type
python setup.py --help
...to get a list of commands. What you are looking to do is...
python setup.py install
For Eclipse Mars use the similar approach as harshit.
1) Help -> Install New Software
2) Use url: http://download.oracle.com/otn_software/oepe/mars repository Above is the OEPE tool provided by oracle for EE development.
3) From all the suggestions, select Glassfish Tools, (Oracle Weblogic Server Tools, Oracle Weblogic Scripting Tools, Oracle patches, Oracle Maven Tools).
4) Install it.
5) Restart eclipse
In point 3) are 4 tools are in braces, I don't know minimal combination, but only install Glassfish Tools has no effect.
During restart Oepe ask for Java 8 JDK if Eclipse run on on older version.
Eclipse 4.5.0 Mars JDK : 1.8
In my case I had to add FormsModule
and ReactiveFormsModule
to the shared.module.ts
too:
(thanks to @Undrium for the code example):
import { NgModule } from '@angular/core'; import { CommonModule } from '@angular/common'; import { FormsModule, ReactiveFormsModule } from '@angular/forms'; @NgModule({ imports: [ CommonModule, ReactiveFormsModule ], declarations: [], exports: [ CommonModule, FormsModule, ReactiveFormsModule ] }) export class SharedModule { }
To just get the index column names df.index.names
will work for both a single Index or MultiIndex as of the most recent version of pandas.
As someone who found this while trying to find the best way to get a list of index names + column names, I would have found this answer useful:
names = list(filter(None, df.index.names + df.columns.values.tolist()))
This works for no index, single column Index, or MultiIndex. It avoids calling reset_index() which has an unnecessary performance hit for such a simple operation. I'm surprised there isn't a built in method for this (that I've come across). I guess I run into needing this more often because I'm shuttling data from databases where the dataframe index maps to a primary/unique key, but is really just another column to me.
The IF
statement does not support logical operators AND
and OR
.
Cascading IF
statements make an implicit conjunction:
IF Exist File1.Dat IF Exist File2.Dat GOTO FILE12_EXIST_LABEL
If File1.Dat
and File2.Dat
exist then jump to the label FILE12_EXIST_LABEL
.
See also: IF /?
You're using an array of objects. Can you use a two dimensional array instead?
http://www.datatables.net/examples/data_sources/js_array.html
See this jsfiddle: http://jsfiddle.net/QhYse/
I used an array like this and it worked fine:
var data = [
["UpdateBootProfile","PASS","00:00:00",[]] ,
["NRB Boot","PASS","00:00:50.5000000",[{"TestName":"TOTAL_TURN_ON_TIME","Result":"PASS","Value":"50.5","LowerLimit":"NaN","UpperLimit":"NaN","ComparisonType":"nctLOG","Units":"SECONDS"}]] ,
["NvMgrCommit","PASS","00:00:00",[]] ,
["SyncNvToEFS","PASS","00:00:01.2500000",[]]
];
Edit to include array of objects
There's a possible solution from this question: jQuery DataTables fnrender with objects
This jsfiddle http://jsfiddle.net/j2C7j/ uses an array of objects. To not get the error I had to pad it with 3 blank values - less than optimal, I know. You may find a better way with fnRender, please post if you do.
var data = [
["","","", {"Name":"UpdateBootProfile","Result":"PASS","ExecutionTime":"00:00:00","Measurement":[]} ]
];
$(function() {
var testsTable = $('#tests').dataTable({
bJQueryUI: true,
aaData: data,
aoColumns: [
{ mData: 'Name', "fnRender": function( oObj ) { return oObj.aData[3].Name}},
{ mData: 'Result' ,"fnRender": function( oObj ) { return oObj.aData[3].Result }},
{ mData: 'ExecutionTime',"fnRender": function( oObj ) { return oObj.aData[3].ExecutionTime } }
]
});
});
You can fix it with ease by adding the following code to your appdelegate.m file in your didFinishLaunchingWithOptions
method:
UIPageControl *pageControl = [UIPageControl appearance];
pageControl.pageIndicatorTintColor = [UIColor darkGrayColor];
pageControl.currentPageIndicatorTintColor = [UIColor orangeColor];
pageControl.backgroundColor = [UIColor whiteColor]
I sometimes exploit this behavior as an alternative to the following pattern:
singleton = None
def use_singleton():
global singleton
if singleton is None:
singleton = _make_singleton()
return singleton.use_me()
If singleton
is only used by use_singleton
, I like the following pattern as a replacement:
# _make_singleton() is called only once when the def is executed
def use_singleton(singleton=_make_singleton()):
return singleton.use_me()
I've used this for instantiating client classes that access external resources, and also for creating dicts or lists for memoization.
Since I don't think this pattern is well known, I do put a short comment in to guard against future misunderstandings.
NP stands for Non-deterministic Polynomial time.
This means that the problem can be solved in Polynomial time using a Non-deterministic Turing machine (like a regular Turing machine but also including a non-deterministic "choice" function). Basically, a solution has to be testable in poly time. If that's the case, and a known NP problem can be solved using the given problem with modified input (an NP problem can be reduced to the given problem) then the problem is NP complete.
The main thing to take away from an NP-complete problem is that it cannot be solved in polynomial time in any known way. NP-Hard/NP-Complete is a way of showing that certain classes of problems are not solvable in realistic time.
Edit: As others have noted, there are often approximate solutions for NP-Complete problems. In this case, the approximate solution usually gives an approximation bound using special notation which tells us how close the approximation is.
Didier have a tool to parse the PDF:
http://didierstevens.com/files/software/pdf-parser_V0_4_3.zip
or here:
http://blog.didierstevens.com/programs/pdf-tools/ which cataloged several related pdf-analysis tools.
Another tool is here:
By the way guys, (int)Decimal.MaxValue will overflow. You can't get the "int" part of a decimal because the decimal is too friggen big to put in the int box. Just checked... its even too big for a long (Int64).
If you want the bit of a Decimal value to the LEFT of the dot, you need to do this:
Math.Truncate(number)
and return the value as... A DECIMAL or a DOUBLE.
edit: Truncate is definitely the correct function!
Right-click the Project. Choose Add Asp.Net Folder. Under The Folder, create two folders one named VBCodeFiles and the Other CSCodeFiles In Web.Config add a new element under compilation
<compilation debug="true" targetFramework="4.5.1">
<codeSubDirectories>
<add directoryName="VBCodeFiles"/>
<add directoryName="CSCodeFiles"/>
</codeSubDirectories>
</compilation>
Now, Create an cshtml page. Add a reference to the VBCodeFiles.Namespace.MyClassName using
@using DMH.VBCodeFiles.Utils.RCMHD
@model MyClassname
Where MyClassName is an class object found in the namespace above. now write out the object in razor using a cshtml file.
<p>@Model.FirstName</p>
Please note, the directoryName="CSCodeFiles" is redundant if this is a C# Project and the directoryName="VBCodeFiles" is redundant if this is a VB.Net project.
iterator
is a more general concept: any object whose class has a __next__
method (next
in Python 2) and an __iter__
method that does return self
.
Every generator is an iterator, but not vice versa. A generator is built by calling a function that has one or more yield
expressions (yield
statements, in Python 2.5 and earlier), and is an object that meets the previous paragraph's definition of an iterator
.
You may want to use a custom iterator, rather than a generator, when you need a class with somewhat complex state-maintaining behavior, or want to expose other methods besides __next__
(and __iter__
and __init__
). Most often, a generator (sometimes, for sufficiently simple needs, a generator expression) is sufficient, and it's simpler to code because state maintenance (within reasonable limits) is basically "done for you" by the frame getting suspended and resumed.
For example, a generator such as:
def squares(start, stop):
for i in range(start, stop):
yield i * i
generator = squares(a, b)
or the equivalent generator expression (genexp)
generator = (i*i for i in range(a, b))
would take more code to build as a custom iterator:
class Squares(object):
def __init__(self, start, stop):
self.start = start
self.stop = stop
def __iter__(self): return self
def __next__(self): # next in Python 2
if self.start >= self.stop:
raise StopIteration
current = self.start * self.start
self.start += 1
return current
iterator = Squares(a, b)
But, of course, with class Squares
you could easily offer extra methods, i.e.
def current(self):
return self.start
if you have any actual need for such extra functionality in your application.
Use mavenCentral()
or jcenter()
adding in the build.gradle
file the script:
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:1.5.0'
}
}
No, but you could return an array containing your values:
function getValues() {
return [getFirstValue(), getSecondValue()];
}
Then you can access them like so:
var values = getValues();
var first = values[0];
var second = values[1];
With the latest ECMAScript 6 syntax*, you can also destructure the return value more intuitively:
const [first, second] = getValues();
If you want to put "labels" on each of the returned values (easier to maintain), you can return an object:
function getValues() {
return {
first: getFirstValue(),
second: getSecondValue(),
};
}
And to access them:
var values = getValues();
var first = values.first;
var second = values.second;
Or with ES6 syntax:
const {first, second} = getValues();
* See this table for browser compatibility. Basically, all modern browsers aside from IE support this syntax, but you can compile ES6 code down to IE-compatible JavaScript at build time with tools like Babel.
That works with :
var element = document.getElementById('myElem');
if (typeof (element) != undefined && typeof (element) != null && typeof (element) != 'undefined') {
console.log('element exists');
}
else{
console.log('element NOT exists');
}
If you are using this query to generate an input file for your Data Warehouse, then you need to format the data appropriately. Essentially in that case you are converting the date (which does have a time component) to a string. You need to explicitly format your string or change your nls_date_format to set the default. In your query you could simply do:
select to_char(some_date, 'yyyy-mm-dd hh24:mi:ss') my_date
from some_table;
To use the window
object is not a good idea. As I see in comments,
'use strict';
function showMessage() {
window.say_hello = 'hello!';
}
console.log(say_hello);
This will throw an error to use the say_hello
variable we need to first call the showMessage function
.
You need to do one thing:
async
before function.const gulp = require('gulp');
gulp.task('message', async function() {
console.log("Gulp is running...");
});
_x000D_
Try to use a filename relative to the current files path. Example for './my_file':
fn = os.path.join(os.path.dirname(__file__), 'my_file')
In Python 3.4+ you can also use pathlib:
fn = pathlib.Path(__file__).parent / 'my_file'
You need to store all of the extra rows in the files in your dictionary, not just one of them:
dict1 = {row[0]: row[1:] for row in r}
...
dict2 = {row[0]: row[1:] for row in r}
Then, since the values in the dictionaries are lists, you need to just concatenate the lists together:
w.writerows([[key] + dict1.get(key, []) + dict2.get(key, []) for key in keys])
You can use dictionary :
x = 0
y = 1
z = 3
list=[]
dict = {0: 'c', 1: 'd', 2: 'e', 3: 'f'}
if x in dict:
list.append(dict[x])
else:
pass
if y in dict:
list.append(dict[y])
else:
pass
if z in dict:
list.append(dict[z])
else:
pass
print list
This seems to occur when .git/HEAD
refers to a branch which does not exist. I ran into this error in a repo that had nothing in .git/refs/heads
. I have no idea how the repo got into that state, I inherited from someone that left the company.
placeBets(betList, stakeAmt)
is an instance method not a static method. You need to create an instance of CBetfairAPI
first:
MyBetfair api = new MyBetfair();
ArrayList bets = api.placeBets(betList, stakeAmt);
With library fpp
, you can easily create time series with date format:
time_ser=ts(data,frequency=4,start=c(1954,2))
here we start at the 2nd quarter of 1954 with quarter fequency.
DTO
is an abbreviation for Data Transfer Object, so it is used to transfer the data between classes and modules of your application.
DTO
should only contain private fields for your data, getters, setters, and constructors.DTO
is not recommended to add business logic methods to such classes, but it is OK to add some util methods.DAO
is an abbreviation for Data Access Object, so it should encapsulate the logic for retrieving, saving and updating data in your data storage (a database, a file-system, whatever).
Here is an example of how the DAO and DTO interfaces would look like:
interface PersonDTO {
String getName();
void setName(String name);
//.....
}
interface PersonDAO {
PersonDTO findById(long id);
void save(PersonDTO person);
//.....
}
The MVC
is a wider pattern. The DTO/DAO would be your model in the MVC pattern.
It tells you how to organize the whole application, not just the part responsible for data retrieval.
As for the second question, if you have a small application it is completely OK, however, if you want to follow the MVC pattern it would be better to have a separate controller, which would contain the business logic for your frame in a separate class and dispatch messages to this controller from the event handlers.
This would separate your business logic from the view.
I noticed in the Android source that almost every operation forces the Bundle to unparcel its data. So if (like me) you need to do this frequently for debugging purposes, the below is very quick to type:
Bundle extras = getIntent().getExtras();
extras.isEmpty(); // unparcel
System.out.println(extras);
You can get more information if you run the following command:
netstat -aon | find /i "listening" |find "port"
using the 'Find' command allows you to filter the results. find /i "listening"
will display only ports that are 'Listening'. Note, you need the /i
to ignore case, otherwise you would type find "LISTENING". | find "port"
will limit the results to only those containing the specific port number. Note, on this it will also filter in results that have the port number anywhere in the response string.
$('#list option').each(function(intIndex){
//do stuff
});
Just tested and QDir::currentPath()
does return the path from which I called my executable.
And a symlink does not "exist". If you are executing an exe from that path you are effectively executing it from the path the symlink points to.
To simplify,
for include
a typical example: between login and verify password
(login) --- << include >> ---> (verify password)
for the login process to success, "verify password" must be successful as well.
for extend
a typical example: between login and show error message (only happened sometimes)
(login) <--- << extend >> --- (show error message)
"show error message" only happens sometimes when the login process failed.
Since Python evaluates also the data type NoneType
as False
during the check, a more precise answer is:
var = False
if var is False:
print('learnt stuff')
This prevents potentially unwanted behaviour such as:
var = [] # or None
if not var:
print('learnt stuff') # is printed what may or may not be wanted
But if you want to check all cases where var
will be evaluated to False
, then doing it by using logical not
keyword is the right thing to do.
The data from the request (content, inputs, files, querystring values) is all on this object HttpContext.Current.Request
To read the posted content
StreamReader reader = new StreamReader(HttpContext.Current.Request.InputStream);
string requestFromPost = reader.ReadToEnd();
To navigate through the all inputs
foreach (string key in HttpContext.Current.Request.Form.AllKeys)
{
string value = HttpContext.Current.Request.Form[key];
}
Left, Right and Below tabs were removed from Bootstrap 3, but you can add custom CSS to achieve this..
.tabs-below > .nav-tabs,
.tabs-right > .nav-tabs,
.tabs-left > .nav-tabs {
border-bottom: 0;
}
.tab-content > .tab-pane,
.pill-content > .pill-pane {
display: none;
}
.tab-content > .active,
.pill-content > .active {
display: block;
}
.tabs-below > .nav-tabs {
border-top: 1px solid #ddd;
}
.tabs-below > .nav-tabs > li {
margin-top: -1px;
margin-bottom: 0;
}
.tabs-below > .nav-tabs > li > a {
-webkit-border-radius: 0 0 4px 4px;
-moz-border-radius: 0 0 4px 4px;
border-radius: 0 0 4px 4px;
}
.tabs-below > .nav-tabs > li > a:hover,
.tabs-below > .nav-tabs > li > a:focus {
border-top-color: #ddd;
border-bottom-color: transparent;
}
.tabs-below > .nav-tabs > .active > a,
.tabs-below > .nav-tabs > .active > a:hover,
.tabs-below > .nav-tabs > .active > a:focus {
border-color: transparent #ddd #ddd #ddd;
}
.tabs-left > .nav-tabs > li,
.tabs-right > .nav-tabs > li {
float: none;
}
.tabs-left > .nav-tabs > li > a,
.tabs-right > .nav-tabs > li > a {
min-width: 74px;
margin-right: 0;
margin-bottom: 3px;
}
.tabs-left > .nav-tabs {
float: left;
margin-right: 19px;
border-right: 1px solid #ddd;
}
.tabs-left > .nav-tabs > li > a {
margin-right: -1px;
-webkit-border-radius: 4px 0 0 4px;
-moz-border-radius: 4px 0 0 4px;
border-radius: 4px 0 0 4px;
}
.tabs-left > .nav-tabs > li > a:hover,
.tabs-left > .nav-tabs > li > a:focus {
border-color: #eeeeee #dddddd #eeeeee #eeeeee;
}
.tabs-left > .nav-tabs .active > a,
.tabs-left > .nav-tabs .active > a:hover,
.tabs-left > .nav-tabs .active > a:focus {
border-color: #ddd transparent #ddd #ddd;
*border-right-color: #ffffff;
}
.tabs-right > .nav-tabs {
float: right;
margin-left: 19px;
border-left: 1px solid #ddd;
}
.tabs-right > .nav-tabs > li > a {
margin-left: -1px;
-webkit-border-radius: 0 4px 4px 0;
-moz-border-radius: 0 4px 4px 0;
border-radius: 0 4px 4px 0;
}
.tabs-right > .nav-tabs > li > a:hover,
.tabs-right > .nav-tabs > li > a:focus {
border-color: #eeeeee #eeeeee #eeeeee #dddddd;
}
.tabs-right > .nav-tabs .active > a,
.tabs-right > .nav-tabs .active > a:hover,
.tabs-right > .nav-tabs .active > a:focus {
border-color: #ddd #ddd #ddd transparent;
*border-left-color: #ffffff;
}
Working example: http://bootply.com/74926
UPDATE
If you don't need the exact look of a tab (bordered appropriately on the left or right as each tab is activated), you can simple use nav-stacked
, along with Bootstrap col-*
to float the tabs to the left or right...
nav-stacked
demo: http://codeply.com/go/rv3Cvr0lZ4
<ul class="nav nav-pills nav-stacked col-md-3">
<li><a href="#a" data-toggle="tab">1</a></li>
<li><a href="#b" data-toggle="tab">2</a></li>
<li><a href="#c" data-toggle="tab">3</a></li>
</ul>
instead of typing in "python". try using "py". for ex:
py -m pip install packagename
py -m pip --install packagename
py -m pip --upgrade packagename
py -m pip upgrade packagename
note: this should be done in the command prompt "cmd" and not in python idle. also FYI pip is installed with python 3.6 automatically.
The short answer is NO. It is not possible to rename a file in Git and remember the history. And it is a pain.
Rumor has it that git log --follow
--find-copies-harder
will work, but it does not work for me, even if there are zero changes to the file contents, and the moves have been made with git mv
.
(Initially I used Eclipse to rename and update packages in one operation, which may have confused Git. But that is a very common thing to do. --follow
does seem to work if only a mv
is performed and then a commit
and the mv
is not too far.)
Linus says that you are supposed to understand the entire contents of a software project holistically, not needing to track individual files. Well, sadly, my small brain cannot do that.
It is really annoying that so many people have mindlessly repeated the statement that Git automatically tracks moves. They have wasted my time. Git does no such thing. By design(!) Git does not track moves at all.
My solution is to rename the files back to their original locations. Change the software to fit the source control. With Git you just seem to need to "git" it right the first time.
Unfortunately, that breaks Eclipse, which seems to use --follow
. git log --follow
sometimes does not show the full history of files with complicated rename histories even though git log
does. (I do not know why.)
(There are some too clever hacks that go back and recommit old work, but they are rather frightening. See GitHub-Gist: emiller/git-mv-with-history.)
Alternatively, you can use requests.Session
and observe cookies
before and after a request:
>>> import requests
>>> session = requests.Session()
>>> print(session.cookies.get_dict())
{}
>>> response = session.get('http://google.com')
>>> print(session.cookies.get_dict())
{'PREF': 'ID=5514c728c9215a9a:FF=0:TM=1406958091:LM=1406958091:S=KfAG0U9jYhrB0XNf', 'NID': '67=TVMYiq2wLMNvJi5SiaONeIQVNqxSc2RAwVrCnuYgTQYAHIZAGESHHPL0xsyM9EMpluLDQgaj3db_V37NjvshV-eoQdA8u43M8UwHMqZdL-S2gjho8j0-Fe1XuH5wYr9v'}
Try this one:
p.pos_fixed {
position:fixed;
top:30px;
right:5px;
}
The most simple solution and easiest way is to add shadow for all four side. CSS
box-shadow: 0 0 2px 2px #ccc; /* with blur shadow*/
box-shadow: 0 0 0 2px #ccc; /* without blur shadow*/
The problem is in the Cordova settings.
Note this:
iPhone Distribution has been manually specified
This didn’t make any sense to me, since I had set the project to auto sign in xcode. Like you, the check and uncheck didn’t work. But then I read the last file path given and followed it. The file path is APP > Platforms > ios > Cordova > build-release.xconfig
And in the file, iPhone Distribution is explicitly set for CODE_SIGN_IDENTITY
.
Change:
CODE_SIGN_IDENTITY = iPhone Distribution
CODE_SIGN_IDENTITY[sdk=iphoneos*] = iPhone Distribution
To:
CODE_SIGN_IDENTITY = iPhone Developer
CODE_SIGN_IDENTITY[sdk=iphoneos*] = iPhone Developer
It a simple thing, and the error message does make it clear that iPhone Distribution has been manually specified, but it doesn’t really say where unless you follow the path. I looked and fiddled with xcode for about three hours trying to figure this out. Hopes this helps anyone in the future.
SimpleDateFormat dateFormat = new SimpleDateFormat("dd/mm/yyyy hh:mm:ss a");
use hh
in place of HH
I had the same issue but with pages which were page cached. Pages got buffered with a stale authenticity token and all actions using the methods post/put/delete where recognized as forgery attempts. Error (422 Unprocessable Entity) was returned to the user.
The solution for Rails 3:
Add:
skip_before_filter :verify_authenticity_token
or as "sagivo" pointed out in Rails 4 add:
skip_before_action :verify_authenticity_token
On pages which do caching.
As @toobulkeh commented this is not a vulnerability on :index
, :show
actions, but beware using this on :put
, :post
actions.
For example:
caches_page :index, :show
skip_before_filter :verify_authenticity_token, :only => [:index, :show]
Reference: http://api.rubyonrails.org/classes/ActionController/RequestForgeryProtection/ClassMethods.html
Note added by barlop- Rails 4.2 deprecated skip_before_filter in favour of skip_before_action https://guides.rubyonrails.org/4_2_release_notes.html "The *_filter family of methods have been removed from the documentation. Their usage is discouraged in favor of the *_action family of methods"
For Rails 6 (as "collimarco" pointed out) you can use skip_forgery_protection
and that it is safe to use it for a REST API that doesn't use session data.
Look this:
List<Client> result = clients
.stream()
.filter(c ->
(users.stream().map(User::getName).collect(Collectors.toList())).contains(c.getName()))
.collect(Collectors.toList());
Another aspect is security (obfuscation). Once a piece of code is extracted from the main application and put in a "separated" Dynamic-Link Library, it is easier to attack, analyse (reverse-engineer) the code, since it has been isolated. When the same piece of code is kept in a LIB Library, it is part of the compiled (linked) target application, and this thus harder to isolate (differentiate) that piece of code from the rest of the target binaries.
Use ListViewSubItem - See: MSDN
I discovered today that we can now debug Javascript With the developer tool bar plugins integreted in IE 8.
You can use watch, breakpoint, see the call stack etc, similarly to debuggers in professional browsers.
You can also use the statement debugger;
in your JavaScript code the set a breakpoint.
I was facing similar problems trying to do some dat import on an intermediate schema (that later we move on to the final one). As we rely on things like extensions (for example PostGIS), the "run_insert" sql file did not fully solved the problem.
After a while, we've found that at least with Postgres 9.3 the solution is far easier... just create your SQL script always specifying the schema when refering to the table:
CREATE TABLE "my_schema"."my_table" (...);
COPY "my_schema"."my_table" (...) FROM stdin;
This way using psql -f xxxxx
works perfectly, and you don't need to change search_paths nor use intermediate files (and won't hit extension schema problems).
SELECT id FROM tbl GROUP BY cat HAVING MAX(date)
Online Viewstate Viewer made by Lachlan Keown:
http://lachlankeown.blogspot.com/2008/05/online-viewstate-viewer-decoder.html
Helped in my case:
import os
os.environ["SPARK_HOME"] = "/usr/local/Cellar/apache-spark/1.5.1/"
os.environ["PYSPARK_PYTHON"]="/usr/local/bin/python3"
You probably want something like this overload of String.Join:
String.Join<T> Method (String, IEnumerable<T>)
Docs:
http://msdn.microsoft.com/en-us/library/dd992421.aspx
In your example, you'd use
String.Join("", Client);
Let me know if this works. Way to detect an Apple device (Mac computers, iPhones, etc.) with help from StackOverflow.com:
What is the list of possible values for navigator.platform as of today?
var deviceDetect = navigator.platform;
var appleDevicesArr = ['MacIntel', 'MacPPC', 'Mac68K', 'Macintosh', 'iPhone',
'iPod', 'iPad', 'iPhone Simulator', 'iPod Simulator', 'iPad Simulator', 'Pike
v7.6 release 92', 'Pike v7.8 release 517'];
// If on Apple device
if(appleDevicesArr.includes(deviceDetect)) {
// Execute code
}
// If NOT on Apple device
else {
// Execute code
}
Here's a very simple awk script that takes into account all common pitfalls listed in the other answers:
getent passwd | awk -F: -v group_name="wheel" '
BEGIN {
"getent group " group_name | getline groupline;
if (!groupline) exit 1;
split(groupline, groupdef, ":");
guid = groupdef[3];
split(groupdef[4], users, ",");
for (k in users) print users[k]
}
$4 == guid {print $1}'
I'm using this with my ldap-enabled setup, runs on anything with standards-compliant getent & awk, including solaris 8+ and hpux.
First, here's some sample data:
set.seed(1)
dat <- data.frame(one = rnorm(15),
two = sample(LETTERS, 15),
three = rnorm(15),
four = runif(15))
dat <- data.frame(lapply(dat, function(x) { x[sample(15, 5)] <- NA; x }))
head(dat)
# one two three four
# 1 NA M 0.80418951 0.8921983
# 2 0.1836433 O -0.05710677 NA
# 3 -0.8356286 L 0.50360797 0.3899895
# 4 NA E NA NA
# 5 0.3295078 S NA 0.9606180
# 6 -0.8204684 <NA> -1.28459935 0.4346595
Here's our replacement:
dat[["four"]][is.na(dat[["four"]])] <- 0
head(dat)
# one two three four
# 1 NA M 0.80418951 0.8921983
# 2 0.1836433 O -0.05710677 0.0000000
# 3 -0.8356286 L 0.50360797 0.3899895
# 4 NA E NA 0.0000000
# 5 0.3295078 S NA 0.9606180
# 6 -0.8204684 <NA> -1.28459935 0.4346595
Alternatively, you can, of course, write dat$four[is.na(dat$four)] <- 0
With Eclipse Collections you could create a primitive double list, sort it and then reverse it to put it in descending order. This approach would avoid boxing the doubles.
MutableDoubleList doubleList =
DoubleLists.mutable.with(
0.5, 0.2, 0.9, 0.1, 0.1, 0.1, 0.54, 0.71,
0.71, 0.71, 0.92, 0.12, 0.65, 0.34, 0.62)
.sortThis().reverseThis();
doubleList.each(System.out::println);
If you want a List<Double>
, then the following would work.
List<Double> objectList =
Lists.mutable.with(
0.5, 0.2, 0.9, 0.1, 0.1, 0.1, 0.54, 0.71,
0.71, 0.71, 0.92, 0.12, 0.65, 0.34, 0.62)
.sortThis(Collections.reverseOrder());
objectList.forEach(System.out::println);
If you want to keep the type as ArrayList<Double>
, you can initialize and sort the list using the ArrayListIterate
utility class as follows:
ArrayList<Double> arrayList =
ArrayListIterate.sortThis(
new ArrayList<>(objectList), Collections.reverseOrder());
arrayList.forEach(System.out::println);
Note: I am a committer for Eclipse Collections.
If it's a major concern to start doing a lot of testing on a Mac, then I would definitely suggest buying a second hand Mac, or perhaps building a Hackintosh. The former gets you up and running quickly, the latter gives you a lot of power for the same price.
For just the odd piece of testing, running OS X in VMWare on your current PC is a cheaper option.
Doesn't need any additional methods after waitKey(0)
(reply for above code)
import cv2
img=cv2.imread('C:/Python27/03323_HD.jpg')
cv2.imshow('ImageWindow',img)
cv2.waitKey(0)
Window appears -> Click on the Window & Click on Enter. Window will close.
One method I can think of is this:
1) Let the UI bind to the service.
2) Expose a method like the one below by the Binder
that registers your Handler
:
public void registerHandler(Handler handler) {
mHandler = handler;
}
3) In the UI thread, call the above method after binding to the service:
mBinder.registerHandler(new Handler());
4) Use the handler in the Service's thread to post your task:
mHandler.post(runnable);
One of the easiest ways is to convert to Array:
for(int i = 0; i < set.size(); i++) {
System.out.println(set.toArray()[i]);
}
Don't use data-toggle attribute so that you can control the toggle behavior by yourself. So it will avoid 'race-condition'
my codes:
button group template (written in .erb, embedded ruby for ruby on rails):
<div class="btn-group" id="featuresFilter">
<% _.each(features, function(feature) { %> <button class="btn btn-primary" data="<%= feature %>"><%= feature %></button> <% }); %>
</div>
and javascript:
onChangeFeatures = function(e){
var el=e.target;
$(el).button('toggle');
var features=el.parentElement;
var activeFeatures=$(features).find(".active");
console.log(activeFeatures);
}
onChangeFeatures function will be triggered once the button is clicked.
You could use Linq.
var prod = from p in prods
where p.ID != 1
select p;
I got the same error: SyntaxError: can't assign to literal when I was trying to assign multiple variables in a single line.
I was assigning the values as shown below:
score = 0, isDuplicate = None
When I shifted them to another line, it got resolved:
score = 0
isDuplicate = None
I don't know why python does not allow multiple assignments at the same line but that's how it is done.
There is one more way to asisgn it in single line ie. Separate them with a semicolon in place of comma. Check the code below:
score = 0 ; duplicate = None
Another issue is that you're reading with scanf("%f", &input);
only. If the user types something that can't be interpreted as a C floating-point number, like "pi", the scanf()
call will not assign anything to input
, and won't progress from there. This means it would attempt to keep reading "pi", and failing.
Given the change to while(!feof(stdin))
which other posters are correctly recommending, if you typed "pi" in there would be an endless loop of printing out the former value of input
and printing the prompt, but the program would never process any new input.
scanf()
returns the number of assignments to input variables it made. If it made no assignment, that means it didn't find a floating-point number, and you should read through more input with something like char string[100];scanf("%99s", string);
. This will remove the next string from the input stream (up to 99 characters, anyway - the extra char
is for the null terminator on the string).
You know, this is reminding me of all the reasons I hate scanf()
, and why I use fgets()
instead and then maybe parse it using sscanf()
.
size_t is the size of a pointer.
So in 32 bits or the common ILP32 (integer, long, pointer) model size_t is 32 bits. and in 64 bits or the common LP64 (long, pointer) model size_t is 64 bits (integers are still 32 bits).
There are other models but these are the ones that g++ use (at least by default)
Swift 4 and 5
For example, you have a UITableViewCell
with name MyCell
class MyCell: UITableViewCell {
var delegate:MyCellDelegate!
@IBAction private func myAction(_ sender: UIButton){
delegate.didPressButton(cell: self)
}
}
Now create a protocol
protocol MyCellDelegate {
func didPressButton(cell: UITableViewCell)
}
Next step, create an Extension of UITableView
extension UITableView {
func returnIndexPath(cell: UITableViewCell) -> IndexPath?{
guard let indexPath = self.indexPath(for: cell) else {
return nil
}
return indexPath
}
}
In your UIViewController
implement the protocol MyCellDelegate
class ViewController: UIViewController, MyCellDelegate {
func didPressButton(cell: UITableViewCell) {
if let indexpath = self.myTableView.returnIndexPath(cell: cell) {
print(indexpath)
}
}
}
In UIViewController
override func viewDidLoad() {
super.viewDidLoad()
//using the same `UITableView extension` get the IndexPath here
didPressButton = { cell in
if let indexpath = self.myTableView.returnIndexPath(cell: cell) {
print(indexpath)
}
}
}
var didPressButton: ((UITableViewCell) -> Void)
class MyCell: UITableViewCell {
@IBAction private func myAction(_ sender: UIButton){
didPressButton(self)
}
}
Note:- if you want to get
UICollectionView
indexPath you can use thisUICollectionView extension
and repeat the above steps
extension UICollectionView {
func returnIndexPath(cell: UICollectionViewCell) -> IndexPath?{
guard let indexPath = self.indexPath(for: cell) else {
return nil
}
return indexPath
}
}
I notice others have given the non-lambda syntax so just to have this complete I'll put in the lambda syntax equivalent:
Non-lambda (as per James's post):
var name = from i in DataContext.MyTable
where i.ID == 0
select i.Name
Equivalent lambda syntax:
var name = DataContext.MyTable.Where(i => i.ID == 0)
.Select(i => new { Name = i.Name });
There's not really much practical difference, just personal opinion on which you prefer.
Just to extend the pratical scope of the question and as an appendix to the given answers: Sometimes one might find it necessary to specify the selectors a little bit more.
By defining the the full span as display:inline-block you might have a hard time displaying images.
Therefore I prefer to define a span like so:
span {
display:block;
width:150px;
word-wrap:break-word;
}
p span, a span,
h1 span, h2 span, h3 span, h4 span, h5 span {
display:inline-block;
}
img{
display:block;
}
Below mentioned link gives the clear explanation with example.
http://www.aspsnippets.com/Articles/Open-Show-jQuery-UI-Dialog-Modal-Popup-on-Button-Click.aspx
Code from the same link
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/jquery-ui.js" type="text/javascript"></script>
<link href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/themes/blitzer/jquery-ui.css"
rel="stylesheet" type="text/css" />
<script type="text/javascript">
$(function () {
$("#dialog").dialog({
modal: true,
autoOpen: false,
title: "jQuery Dialog",
width: 300,
height: 150
});
$("#btnShow").click(function () {
$('#dialog').dialog('open');
});
});
</script>
<input type="button" id="btnShow" value="Show Popup" />
<div id="dialog" style="display: none" align = "center">
This is a jQuery Dialog.
</div>
For the records: the official documentation, as for Spring Boot v1.2.0.RELEASE and Spring v4.1.3.RELEASE:
If the only change you need to make to logging is to set the levels of various loggers then you can do that in application.properties using the "logging.level" prefix, e.g.
logging.level.org.springframework.web: DEBUG
logging.level.org.hibernate: ERROR
You can also set the location of a file to log to (in addition to the console) using "logging.file".
To configure the more fine-grained settings of a logging system you need to use the native configuration format supported by the LoggingSystem in question. By default Spring Boot picks up the native configuration from its default location for the system (e.g. classpath:logback.xml for Logback), but you can set the location of the config file using the "logging.config" property.
What role do they play when exiting an application in C#?
The same as every other application. Basically they get returned to the caller. Irrelvant if ythe start was an iicon double click. Relevant is the call is a batch file that decides whether the app worked on the return code. SO, unless you write a program that needs this, the return dcode IS irrelevant.
But what is the difference?
One comes from environment one from the System.Windows.Forms?.Application. Functionall there should not bbe a lot of difference.
Solution:
Dowload the ultimate version of Gradle
http://services.gradle.org/distributions/
gradle-4.x-rc-1-all.zip.sha256 09-Jan-2018 01:15 +0000 64.00B
Unzip the distribution
Go to Android Studio -> File -> Settings -> Gradle -> Use local gradle distribution Search the file and OK
In the gradle:app write this, implementation(path: ':animators', configuration: 'default')
dependencies {
.
.
.
implementation project(path: ':animators', configuration: 'default')
}
Change the position
attribute to fixed
instead of absolute
.
While the other answers are mostly fine, you could try another, more space-efficient, encoding method like yEnc. (yEnc wikipedia link) With yEnc also get checksum capability right "out of the box". Read and links below. Of course, because XML does not have a native yEnc type your XML schema should be updated to properly describe the encoded node.
Why: Due to the encoding strategies base64/63, uuencode et al. encodings increase the amount of data (overhead) you need to store and transfer by roughly 40% (vs. yEnc's 1-2%). Depending on what you're encoding, 40% overhead could be/become an issue.
yEnc - Wikipedia abstract: https://en.wikipedia.org/wiki/YEnc yEnc is a binary-to-text encoding scheme for transferring binary files in messages on Usenet or via e-mail. ... An additional advantage of yEnc over previous encoding methods, such as uuencode and Base64, is the inclusion of a CRC checksum to verify that the decoded file has been delivered intact. ?
There is a much easier way to get the smooth scroll effect without javascript. In your CSS just target the entire html tag and give it scroll-behavior: smooth;
html {_x000D_
scroll-behavior: smooth;_x000D_
}_x000D_
_x000D_
a {_x000D_
text-decoration: none;_x000D_
color: black;_x000D_
} _x000D_
_x000D_
#down {_x000D_
margin-top: 100%;_x000D_
padding-bottom: 25%;_x000D_
}
_x000D_
<html>_x000D_
<a href="#down">Click Here to Smoothly Scroll Down</a>_x000D_
<div id="down">_x000D_
<h1>You are down!</h1>_x000D_
</div>_x000D_
</html
_x000D_
The "scroll-behavior" is telling the page how it should scroll and is so much easier than using javascript. Javascript will give you more options on speed and the smoothness but this will deliver without all of the confusing code.
barryvdh/laravel-cors works perfectly with Laravel 5.1 with just a few key points in enabling it.
After adding it as a composer dependency, make sure you have published the CORS config file and adjusted the CORS headers as you want them. Here is how mine look in app/config/cors.php
<?php
return [
'supportsCredentials' => true,
'allowedOrigins' => ['*'],
'allowedHeaders' => ['*'],
'allowedMethods' => ['GET', 'POST', 'PUT', 'DELETE'],
'exposedHeaders' => ['DAV', 'content-length', 'Allow'],
'maxAge' => 86400,
'hosts' => [],
];
After this, there is one more step that's not mentioned in the documentation, you have to add the CORS handler 'Barryvdh\Cors\HandleCors'
in the App kernel. I prefer to use it in the global middleware stack. Like this
/**
* The application's global HTTP middleware stack.
*
* @var array
*/
protected $middleware = [
'Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode',
'Illuminate\Cookie\Middleware\EncryptCookies',
'Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse',
'Illuminate\Session\Middleware\StartSession',
'Illuminate\View\Middleware\ShareErrorsFromSession',
'Barryvdh\Cors\HandleCors',
];
But its up to you to use it as a route middleware and place on specific routes.
This should make the package work with L5.1
I had to do a :
git checkout -b master
as git said that it doesn't exists, because it's been wipe with the
git -D master
You need to specify the primary key as auto-increment
CREATE TABLE `momento_distribution`
(
`momento_id` INT(11) NOT NULL AUTO_INCREMENT,
`momento_idmember` INT(11) NOT NULL,
`created_at` DATETIME DEFAULT NULL,
`updated_at` DATETIME DEFAULT NULL,
`unread` TINYINT(1) DEFAULT '1',
`accepted` VARCHAR(10) NOT NULL DEFAULT 'pending',
`ext_member` VARCHAR(255) DEFAULT NULL,
PRIMARY KEY (`momento_id`, `momento_idmember`),
KEY `momento_distribution_FI_2` (`momento_idmember`),
KEY `accepted` (`accepted`, `ext_member`)
)
ENGINE=InnoDB
DEFAULT CHARSET=latin1$$
With regards to comment below, how about:
ALTER TABLE `momento_distribution`
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT,
DROP PRIMARY KEY,
ADD PRIMARY KEY (`id`);
A PRIMARY KEY is a unique index, so if it contains duplicates, you cannot assign the column to be unique index, so you may need to create a new column altogether
try this code for different input element different style
your css selector::-webkit-input-placeholder { /*for webkit */
color:#909090;
opacity:1;
}
your css selector:-moz-placeholder { /*for mozilla */
color:#909090;
opacity:1;
}
your css selector:-ms-input-placeholder { /*for for internet exprolar */
color:#909090;
opacity:1;
}
example 1:
input[type="text"]::-webkit-input-placeholder { /*for webkit */
color: red;
opacity:1;
}
input[type="text"]:-moz-placeholder { /*for mozilla */
color: red;
opacity:1;
}
input[type="text"]:-ms-input-placeholder { /*for for internet exprolar */
color: red;
opacity:1;
}
example 2:
input[type="email"]::-webkit-input-placeholder { /*for webkit */
color: gray;
opacity:1;
}
input[type="email"]:-moz-placeholder { /*for mozilla */
color: gray;
opacity:1;
}
input[type="email"]:-ms-input-placeholder { /*for for internet exprolar */
color: gray;
}
It works for me when sending an attachment to Mercadolibre, through its messaging system.
The anwswer https://stackoverflow.com/a/35227055/7656744
$target_url = "http://server:port/xxxxx.php";
$fname = 'file.txt';
$cfile = new CURLFile(realpath($fname));
$post = array (
'file' => $cfile
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $target_url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible;)");
curl_setopt($ch, CURLOPT_HTTPHEADER,array('Content-Type: multipart/form-data'));
curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 100);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
$result = curl_exec ($ch);
if ($result === FALSE) {
echo "Error sending" . $fname . " " . curl_error($ch);
curl_close ($ch);
}else{
curl_close ($ch);
echo "Result: " . $result;
}
Relative vs Absolute:
Just create your own action.
namespace WpfUtil
{
using System.Reflection;
using System.Windows;
using System.Windows.Interactivity;
/// <summary>
/// Sets the designated property to the supplied value. TargetObject
/// optionally designates the object on which to set the property. If
/// TargetObject is not supplied then the property is set on the object
/// to which the trigger is attached.
/// </summary>
public class SetPropertyAction : TriggerAction<FrameworkElement>
{
// PropertyName DependencyProperty.
/// <summary>
/// The property to be executed in response to the trigger.
/// </summary>
public string PropertyName
{
get { return (string)GetValue(PropertyNameProperty); }
set { SetValue(PropertyNameProperty, value); }
}
public static readonly DependencyProperty PropertyNameProperty
= DependencyProperty.Register("PropertyName", typeof(string),
typeof(SetPropertyAction));
// PropertyValue DependencyProperty.
/// <summary>
/// The value to set the property to.
/// </summary>
public object PropertyValue
{
get { return GetValue(PropertyValueProperty); }
set { SetValue(PropertyValueProperty, value); }
}
public static readonly DependencyProperty PropertyValueProperty
= DependencyProperty.Register("PropertyValue", typeof(object),
typeof(SetPropertyAction));
// TargetObject DependencyProperty.
/// <summary>
/// Specifies the object upon which to set the property.
/// </summary>
public object TargetObject
{
get { return GetValue(TargetObjectProperty); }
set { SetValue(TargetObjectProperty, value); }
}
public static readonly DependencyProperty TargetObjectProperty
= DependencyProperty.Register("TargetObject", typeof(object),
typeof(SetPropertyAction));
// Private Implementation.
protected override void Invoke(object parameter)
{
object target = TargetObject ?? AssociatedObject;
PropertyInfo propertyInfo = target.GetType().GetProperty(
PropertyName,
BindingFlags.Instance|BindingFlags.Public
|BindingFlags.NonPublic|BindingFlags.InvokeMethod);
propertyInfo.SetValue(target, PropertyValue);
}
}
}
In this case I'm binding to a property called DialogResult on my viewmodel.
<Grid>
<Button>
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<wpf:SetPropertyAction PropertyName="DialogResult" TargetObject="{Binding}"
PropertyValue="{x:Static mvvm:DialogResult.Cancel}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
Cancel
</Button>
</Grid>
Old post but wanted to ensure newcomers are aware of Stored procedures.
My 10¢ worth here is that if you are able to write your SQL statement as a stored procedure, that in my view is the optimum approach. I ALWAYS use stored procs and never loop through records in my main code. For Example: SQL Table > SQL Stored Procedures > IIS/Dot.NET > Class
.
When you use stored procedures, you can restrict the user to EXECUTE permission only, thus reducing security risks.
Your stored procedure is inherently paramerised, and you can specify input and output parameters.
The stored procedure (if it returns data via SELECT
statement) can be accessed and read in the exact same way as you would a regular SELECT
statement in your code.
It also runs faster as it is compiled on the SQL Server.
Did I also mention you can do multiple steps, e.g. update
a table, check values on another DB server, and then once finally finished, return data to the client, all on the same server, and no interaction with the client. So this is MUCH faster than coding this logic in your code.
Give width of image as match_parent and height as required, say 300 dp.
<ImageView
android:id = "@+id/imgXYZ"
android:layout_width = "match_parent"
android:layout_height = "300dp"
android:src="@drawable/imageXYZ"
/>
In my program, I use some logic to judge if it was onload: watching it's network request, if there was no new request on past 200ms, I treat it onload.
Use this, after onLoadFinish().
function onLoadComplete(page, callback){
var waiting = []; // request id
var interval = 200; //ms time waiting new request
var timer = setTimeout( timeout, interval);
var max_retry = 3; //
var counter_retry = 0;
function timeout(){
if(waiting.length && counter_retry < max_retry){
timer = setTimeout( timeout, interval);
counter_retry++;
return;
}else{
try{
callback(null, page);
}catch(e){}
}
}
//for debug, log time cost
var tlogger = {};
bindEvent(page, 'request', function(req){
waiting.push(req.id);
});
bindEvent(page, 'receive', function (res) {
var cT = res.contentType;
if(!cT){
console.log('[contentType] ', cT, ' [url] ', res.url);
}
if(!cT) return remove(res.id);
if(cT.indexOf('application') * cT.indexOf('text') != 0) return remove(res.id);
if (res.stage === 'start') {
console.log('!!received start: ', res.id);
//console.log( JSON.stringify(res) );
tlogger[res.id] = new Date();
}else if (res.stage === 'end') {
console.log('!!received end: ', res.id, (new Date() - tlogger[res.id]) );
//console.log( JSON.stringify(res) );
remove(res.id);
clearTimeout(timer);
timer = setTimeout(timeout, interval);
}
});
bindEvent(page, 'error', function(err){
remove(err.id);
if(waiting.length === 0){
counter_retry = 0;
}
});
function remove(id){
var i = waiting.indexOf( id );
if(i < 0){
return;
}else{
waiting.splice(i,1);
}
}
function bindEvent(page, evt, cb){
switch(evt){
case 'request':
page.onResourceRequested = cb;
break;
case 'receive':
page.onResourceReceived = cb;
break;
case 'error':
page.onResourceError = cb;
break;
case 'timeout':
page.onResourceTimeout = cb;
break;
}
}
}
A "JSON object" is actually an oxymoron. JSON is a text format describing an object, not an actual object, so data can either be in the form of JSON, or deserialised into an object.
The JSON for that would look like this:
{"KEY1":{"NAME":"XXXXXX","VALUE":100},"KEY2":{"NAME":"YYYYYYY","VALUE":200},"KEY3":{"NAME":"ZZZZZZZ","VALUE":500}}
Once you have parsed the JSON into a Javascript object (called data
in the code below), you can for example access the object for KEY2
and it's properties like this:
var obj = data.KEY2;
alert(obj.NAME);
alert(obj.VALUE);
If you have the key as a string, you can use index notation:
var key = 'KEY3';
var obj = data[key];
request.FILES['filename'].name
From the request
documentation.
If you don't know the key, you can iterate over the files:
for filename, file in request.FILES.iteritems():
name = request.FILES[filename].name
If you have
varname <- c("a", "b", "d")
you can do
get(varname[1]) + 2
for
a + 2
or
assign(varname[1], 2 + 2)
for
a <- 2 + 2
So it looks like you use GET when you want to evaluate a formula that uses a variable (such as a concatenate), and ASSIGN when you want to assign a value to a pre-declared variable.
Syntax for assign: assign(x, value)
x: a variable name, given as a character string. No coercion is done, and the first element of a character vector of length greater than one will be used, with a warning.
value: value to be assigned to x.
android:hint="Enter your question" or something like this must work. I am using Relative layout with EditText as If you want to use password,say android:inputType="textPassword" for hiding characters and "textVisiblePassword" for showing what you enter as password.
As other have said, you want to use either puts
or p
. Why? Is that magic?
Actually not. A rails console is, under the hood, an IRB, so all you can do in IRB you will be able to do in a rails console. Since for printing in an IRB we use puts
, we use the same command for printing in a rails console.
You can actually take a look at the console code in the rails source code. See the require of irb? :)
This can be done in 2 ways. Let person be the class we are going to use to demonstrate it.
public class Person {
private String name;
private int age;
public String getAge() {
return age;
}
}
Let persons be the list of Persons to be converted to the map
1.Using Simple foreach and a Lambda Expression on the List
Map<Integer,List<Person>> mapPersons = new HashMap<>();
persons.forEach(p->mapPersons.put(p.getAge(),p));
2.Using Collectors on Stream defined on the given List.
Map<Integer,List<Person>> mapPersons =
persons.stream().collect(Collectors.groupingBy(Person::getAge));
Well there are thousand ways to edit a Text file on windows 7. Usually people Install Sublime , Atom and Notepad++ as an editor. For command line , I think the Basic Edit command (by the way which does not work on 64 bit computers) is good;Alternatively I find type con > filename as a very Applaudable method.If windows is newly installed and One wants to avoid Notepad. This might be it!! The perfect usage of Type as an editor :)
reference of the Image:- https://www.codeproject.com/Articles/34280/How-to-Write-Applet-Code
Here's a simple SQL that updates Mid_Name on the Name3 table using the Middle_Name field from Name:
update name3
set mid_name = name.middle_name
from name
where name3.person_id = name.person_id;
The easiest (and standard) way to install Android SDK under OS X is to use brew
.
brew install android-sdk
If you do not have homebrew, here's how to get it.
This will install Android SDK into /usr/local/Cellar/android-sdk/
and, at this moment, this is the best location to install it.
Rather than locks, I suggest you look at long-running transactions, using v$transaction
. From there you can join to v$session
, which should give you an idea about the UI (try the program and machine columns) as well as the user.
please check out the IPython configuration system, implemented via traitlets for the type enforcement you are doing manually.
Cut and pasted here to comply with SO guidelines for not just dropping links as the content of links changes over time.
Here are the main requirements we wanted our configuration system to have:
Support for hierarchical configuration information.
Full integration with command line option parsers. Often, you want to read a configuration file, but then override some of the values with command line options. Our configuration system automates this process and allows each command line option to be linked to a particular attribute in the configuration hierarchy that it will override.
Configuration files that are themselves valid Python code. This accomplishes many things. First, it becomes possible to put logic in your configuration files that sets attributes based on your operating system, network setup, Python version, etc. Second, Python has a super simple syntax for accessing hierarchical data structures, namely regular attribute access (Foo.Bar.Bam.name). Third, using Python makes it easy for users to import configuration attributes from one configuration file to another. Fourth, even though Python is dynamically typed, it does have types that can be checked at runtime. Thus, a 1 in a config file is the integer ‘1’, while a '1' is a string.
A fully automated method for getting the configuration information to the classes that need it at runtime. Writing code that walks a configuration hierarchy to extract a particular attribute is painful. When you have complex configuration information with hundreds of attributes, this makes you want to cry.
Type checking and validation that doesn’t require the entire configuration hierarchy to be specified statically before runtime. Python is a very dynamic language and you don’t always know everything that needs to be configured when a program starts.
To acheive this they basically define 3 object classes and their relations to each other:
1) Configuration - basically a ChainMap / basic dict with some enhancements for merging.
2) Configurable - base class to subclass all things you'd wish to configure.
3) Application - object that is instantiated to perform a specific application function, or your main application for single purpose software.
In their words:
Application: Application
An application is a process that does a specific job. The most obvious application is the ipython command line program. Each application reads one or more configuration files and a single set of command line options and then produces a master configuration object for the application. This configuration object is then passed to the configurable objects that the application creates. These configurable objects implement the actual logic of the application and know how to configure themselves given the configuration object.
Applications always have a log attribute that is a configured Logger. This allows centralized logging configuration per-application. Configurable: Configurable
A configurable is a regular Python class that serves as a base class for all main classes in an application. The Configurable base class is lightweight and only does one things.
This Configurable is a subclass of HasTraits that knows how to configure itself. Class level traits with the metadata config=True become values that can be configured from the command line and configuration files.
Developers create Configurable subclasses that implement all of the logic in the application. Each of these subclasses has its own configuration information that controls how instances are created.
PDFBox is the best library I've found for this purpose, it's comprehensive and really quite easy to use if you're just doing basic text extraction. Examples can be found here.
It explains it on the page, but one thing to watch out for is that the start and end indexes when using setStartPage() and setEndPage() are both inclusive. I skipped over that explanation first time round and then it took me a while to realise why I was getting more than one page back with each call!
Itext is another alternative that also works with C#, though I've personally never used it. It's more low level than PDFBox, so less suited to the job if all you need is basic text extraction.
You can also use this
#define IPAD UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad
...
if (IPAD) {
// iPad
} else {
// iPhone / iPod Touch
}
If its calling spring boot service. you can handle it using below code.
@Bean
public WebMvcConfigurer corsConfigurer() {
return new WebMvcConfigurerAdapter() {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/**")
.allowedOrigins("*")
.allowedMethods("GET", "POST", "PUT", "DELETE", "HEAD", "OPTIONS")
.allowedHeaders("*", "Access-Control-Allow-Headers", "origin", "Content-type", "accept", "x-requested-with", "x-requested-by") //What is this for?
.allowCredentials(true);
}
};
}
This example demonstrates the difference between the mousemove, mouseenter and mouseover events:
https://jsfiddle.net/z8g613yd/
HTML:
<div onmousemove="myMoveFunction()">
<p>onmousemove: <br> <span id="demo">Mouse over me!</span></p>
</div>
<div onmouseenter="myEnterFunction()">
<p>onmouseenter: <br> <span id="demo2">Mouse over me!</span></p>
</div>
<div onmouseover="myOverFunction()">
<p>onmouseover: <br> <span id="demo3">Mouse over me!</span></p>
</div>
CSS:
div {
width: 200px;
height: 100px;
border: 1px solid black;
margin: 10px;
float: left;
padding: 30px;
text-align: center;
background-color: lightgray;
}
p {
background-color: white;
height: 50px;
}
p span {
background-color: #86fcd4;
padding: 0 20px;
}
JS:
var x = 0;
var y = 0;
var z = 0;
function myMoveFunction() {
document.getElementById("demo").innerHTML = z += 1;
}
function myEnterFunction() {
document.getElementById("demo2").innerHTML = x += 1;
}
function myOverFunction() {
document.getElementById("demo3").innerHTML = y += 1;
}
onmousemove
: occurs every time the mouse pointer is moved over the div element.onmouseenter
: only occurs when the mouse pointer enters the div element.onmouseover
: occurs when the mouse pointer enters the div element,
and its child elements (p and span).Sure. The easiest is probably to write a wrapper around preg_match:
function limitString($string, $limit = 100) {
// Return early if the string is already shorter than the limit
if(strlen($string) < $limit) {return $string;}
$regex = "/(.{1,$limit})\b/";
preg_match($regex, $string, $matches);
return $matches[1];
}
EDIT : Updated to not ALWAYS include a space as the last character in the string
try below code it will solve your problem.
Configuration configuration = new Configuration().configure("/logic/hibernate.cfg.xml");
Here is a small example how to add a matplotlib grid in Gtk3 with Python 2 (not working in Python 3):
#!/usr/bin/env python
#-*- coding: utf-8 -*-
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
from matplotlib.figure import Figure
from matplotlib.backends.backend_gtk3agg import FigureCanvasGTK3Agg as FigureCanvas
win = Gtk.Window()
win.connect("delete-event", Gtk.main_quit)
win.set_title("Embedding in GTK3")
f = Figure(figsize=(1, 1), dpi=100)
ax = f.add_subplot(111)
ax.grid()
canvas = FigureCanvas(f)
canvas.set_size_request(400, 400)
win.add(canvas)
win.show_all()
Gtk.main()
You can also upload using HTML5. You can use this AJAX uploader.
The JS code is basically:
$scope.doPhotoUpload = function () {
// ..
var myUploader = new uploader(document.getElementById('file_upload_element_id'), options);
myUploader.send();
// ..
}
Which reads from an HTML input element
<input id="file_upload_element_id" type="file" onchange="angular.element(this).scope().doPhotoUpload()">