Programs & Examples On #Curl language

a reflective object-oriented programming language for interactive web applications.

android set button background programmatically

Further from @finnmglas, the Java answer as of 2021 is:

    if (Build.VERSION.SDK_INT >= 29)
        btn.getBackground().setColorFilter(new BlendModeColorFilter(color, BlendMode.MULTIPLY));
    else
        btn.getBackground().setColorFilter(color, PorterDuff.Mode.MULTIPLY);

Tomcat is not running even though JAVA_HOME path is correct

Also ensure that you have the correct version of Tomcat for the CPU type. I had installed a 64bit tomcat on a 32bit O/S but it was giving me the JAVA_HOME exception when that wasn't the case at all.

How to insert a line break in a SQL Server VARCHAR/NVARCHAR string

I'd say

concat('This is line 1.', 0xd0a, 'This is line 2.')

or

concat(N'This is line 1.', 0xd000a, N'This is line 2.')

How can I start InternetExplorerDriver using Selenium WebDriver

In c#, This can bypass changing protected zone settings.

var options = new InternetExplorerOptions();
options.IntroduceInstabilityByIgnoringProtectedModeSettings = true;
options.ElementScrollBehavior = InternetExplorerElementScrollBehavior.Bottom;

Can not deserialize instance of java.util.ArrayList out of VALUE_STRING

For people that find this question by searching for the error message, you can also see this error if you make a mistake in your @JsonProperty annotations such that you annotate a List-typed property with the name of a single-valued field:

@JsonProperty("someSingleValuedField") // Oops, should have been "someMultiValuedField"
public List<String> getMyField() { // deserialization fails - single value into List
  return myField;
}

How to know the git username and email saved during configuration?

List all variables set in the config file, along with their values.

git config --list

If you are new to git then use the following commands to set a user name and email address.

Set user name

git config --global user.name "your Name"

Set user email

git config --global user.email "[email protected]"

Check user name

git config user.name

Check user email

git config user.email

What are metaclasses in Python?

Classes as objects

Before understanding metaclasses, you need to master classes in Python. And Python has a very peculiar idea of what classes are, borrowed from the Smalltalk language.

In most languages, classes are just pieces of code that describe how to produce an object. That's kinda true in Python too:

>>> class ObjectCreator(object):
...       pass
...

>>> my_object = ObjectCreator()
>>> print(my_object)
<__main__.ObjectCreator object at 0x8974f2c>

But classes are more than that in Python. Classes are objects too.

Yes, objects.

As soon as you use the keyword class, Python executes it and creates an OBJECT. The instruction

>>> class ObjectCreator(object):
...       pass
...

creates in memory an object with the name "ObjectCreator".

This object (the class) is itself capable of creating objects (the instances), and this is why it's a class.

But still, it's an object, and therefore:

  • you can assign it to a variable
  • you can copy it
  • you can add attributes to it
  • you can pass it as a function parameter

e.g.:

>>> print(ObjectCreator) # you can print a class because it's an object
<class '__main__.ObjectCreator'>
>>> def echo(o):
...       print(o)
...
>>> echo(ObjectCreator) # you can pass a class as a parameter
<class '__main__.ObjectCreator'>
>>> print(hasattr(ObjectCreator, 'new_attribute'))
False
>>> ObjectCreator.new_attribute = 'foo' # you can add attributes to a class
>>> print(hasattr(ObjectCreator, 'new_attribute'))
True
>>> print(ObjectCreator.new_attribute)
foo
>>> ObjectCreatorMirror = ObjectCreator # you can assign a class to a variable
>>> print(ObjectCreatorMirror.new_attribute)
foo
>>> print(ObjectCreatorMirror())
<__main__.ObjectCreator object at 0x8997b4c>

Creating classes dynamically

Since classes are objects, you can create them on the fly, like any object.

First, you can create a class in a function using class:

>>> def choose_class(name):
...     if name == 'foo':
...         class Foo(object):
...             pass
...         return Foo # return the class, not an instance
...     else:
...         class Bar(object):
...             pass
...         return Bar
...
>>> MyClass = choose_class('foo')
>>> print(MyClass) # the function returns a class, not an instance
<class '__main__.Foo'>
>>> print(MyClass()) # you can create an object from this class
<__main__.Foo object at 0x89c6d4c>

But it's not so dynamic, since you still have to write the whole class yourself.

Since classes are objects, they must be generated by something.

When you use the class keyword, Python creates this object automatically. But as with most things in Python, it gives you a way to do it manually.

Remember the function type? The good old function that lets you know what type an object is:

>>> print(type(1))
<type 'int'>
>>> print(type("1"))
<type 'str'>
>>> print(type(ObjectCreator))
<type 'type'>
>>> print(type(ObjectCreator()))
<class '__main__.ObjectCreator'>

Well, type has a completely different ability, it can also create classes on the fly. type can take the description of a class as parameters, and return a class.

(I know, it's silly that the same function can have two completely different uses according to the parameters you pass to it. It's an issue due to backward compatibility in Python)

type works this way:

type(name, bases, attrs)

Where:

  • name: name of the class
  • bases: tuple of the parent class (for inheritance, can be empty)
  • attrs: dictionary containing attributes names and values

e.g.:

>>> class MyShinyClass(object):
...       pass

can be created manually this way:

>>> MyShinyClass = type('MyShinyClass', (), {}) # returns a class object
>>> print(MyShinyClass)
<class '__main__.MyShinyClass'>
>>> print(MyShinyClass()) # create an instance with the class
<__main__.MyShinyClass object at 0x8997cec>

You'll notice that we use "MyShinyClass" as the name of the class and as the variable to hold the class reference. They can be different, but there is no reason to complicate things.

type accepts a dictionary to define the attributes of the class. So:

>>> class Foo(object):
...       bar = True

Can be translated to:

>>> Foo = type('Foo', (), {'bar':True})

And used as a normal class:

>>> print(Foo)
<class '__main__.Foo'>
>>> print(Foo.bar)
True
>>> f = Foo()
>>> print(f)
<__main__.Foo object at 0x8a9b84c>
>>> print(f.bar)
True

And of course, you can inherit from it, so:

>>>   class FooChild(Foo):
...         pass

would be:

>>> FooChild = type('FooChild', (Foo,), {})
>>> print(FooChild)
<class '__main__.FooChild'>
>>> print(FooChild.bar) # bar is inherited from Foo
True

Eventually, you'll want to add methods to your class. Just define a function with the proper signature and assign it as an attribute.

>>> def echo_bar(self):
...       print(self.bar)
...
>>> FooChild = type('FooChild', (Foo,), {'echo_bar': echo_bar})
>>> hasattr(Foo, 'echo_bar')
False
>>> hasattr(FooChild, 'echo_bar')
True
>>> my_foo = FooChild()
>>> my_foo.echo_bar()
True

And you can add even more methods after you dynamically create the class, just like adding methods to a normally created class object.

>>> def echo_bar_more(self):
...       print('yet another method')
...
>>> FooChild.echo_bar_more = echo_bar_more
>>> hasattr(FooChild, 'echo_bar_more')
True

You see where we are going: in Python, classes are objects, and you can create a class on the fly, dynamically.

This is what Python does when you use the keyword class, and it does so by using a metaclass.

What are metaclasses (finally)

Metaclasses are the 'stuff' that creates classes.

You define classes in order to create objects, right?

But we learned that Python classes are objects.

Well, metaclasses are what create these objects. They are the classes' classes, you can picture them this way:

MyClass = MetaClass()
my_object = MyClass()

You've seen that type lets you do something like this:

MyClass = type('MyClass', (), {})

It's because the function type is in fact a metaclass. type is the metaclass Python uses to create all classes behind the scenes.

Now you wonder why the heck is it written in lowercase, and not Type?

Well, I guess it's a matter of consistency with str, the class that creates strings objects, and int the class that creates integer objects. type is just the class that creates class objects.

You see that by checking the __class__ attribute.

Everything, and I mean everything, is an object in Python. That includes ints, strings, functions and classes. All of them are objects. And all of them have been created from a class:

>>> age = 35
>>> age.__class__
<type 'int'>
>>> name = 'bob'
>>> name.__class__
<type 'str'>
>>> def foo(): pass
>>> foo.__class__
<type 'function'>
>>> class Bar(object): pass
>>> b = Bar()
>>> b.__class__
<class '__main__.Bar'>

Now, what is the __class__ of any __class__ ?

>>> age.__class__.__class__
<type 'type'>
>>> name.__class__.__class__
<type 'type'>
>>> foo.__class__.__class__
<type 'type'>
>>> b.__class__.__class__
<type 'type'>

So, a metaclass is just the stuff that creates class objects.

You can call it a 'class factory' if you wish.

type is the built-in metaclass Python uses, but of course, you can create your own metaclass.

The __metaclass__ attribute

In Python 2, you can add a __metaclass__ attribute when you write a class (see next section for the Python 3 syntax):

class Foo(object):
    __metaclass__ = something...
    [...]

If you do so, Python will use the metaclass to create the class Foo.

Careful, it's tricky.

You write class Foo(object) first, but the class object Foo is not created in memory yet.

Python will look for __metaclass__ in the class definition. If it finds it, it will use it to create the object class Foo. If it doesn't, it will use type to create the class.

Read that several times.

When you do:

class Foo(Bar):
    pass

Python does the following:

Is there a __metaclass__ attribute in Foo?

If yes, create in-memory a class object (I said a class object, stay with me here), with the name Foo by using what is in __metaclass__.

If Python can't find __metaclass__, it will look for a __metaclass__ at the MODULE level, and try to do the same (but only for classes that don't inherit anything, basically old-style classes).

Then if it can't find any __metaclass__ at all, it will use the Bar's (the first parent) own metaclass (which might be the default type) to create the class object.

Be careful here that the __metaclass__ attribute will not be inherited, the metaclass of the parent (Bar.__class__) will be. If Bar used a __metaclass__ attribute that created Bar with type() (and not type.__new__()), the subclasses will not inherit that behavior.

Now the big question is, what can you put in __metaclass__?

The answer is something that can create a class.

And what can create a class? type, or anything that subclasses or uses it.

Metaclasses in Python 3

The syntax to set the metaclass has been changed in Python 3:

class Foo(object, metaclass=something):
    ...

i.e. the __metaclass__ attribute is no longer used, in favor of a keyword argument in the list of base classes.

The behavior of metaclasses however stays largely the same.

One thing added to metaclasses in Python 3 is that you can also pass attributes as keyword-arguments into a metaclass, like so:

class Foo(object, metaclass=something, kwarg1=value1, kwarg2=value2):
    ...

Read the section below for how python handles this.

Custom metaclasses

The main purpose of a metaclass is to change the class automatically, when it's created.

You usually do this for APIs, where you want to create classes matching the current context.

Imagine a stupid example, where you decide that all classes in your module should have their attributes written in uppercase. There are several ways to do this, but one way is to set __metaclass__ at the module level.

This way, all classes of this module will be created using this metaclass, and we just have to tell the metaclass to turn all attributes to uppercase.

Luckily, __metaclass__ can actually be any callable, it doesn't need to be a formal class (I know, something with 'class' in its name doesn't need to be a class, go figure... but it's helpful).

So we will start with a simple example, by using a function.

# the metaclass will automatically get passed the same argument
# that you usually pass to `type`
def upper_attr(future_class_name, future_class_parents, future_class_attrs):
    """
      Return a class object, with the list of its attribute turned
      into uppercase.
    """
    # pick up any attribute that doesn't start with '__' and uppercase it
    uppercase_attrs = {
        attr if attr.startswith("__") else attr.upper(): v
        for attr, v in future_class_attrs.items()
    }

    # let `type` do the class creation
    return type(future_class_name, future_class_parents, uppercase_attrs)

__metaclass__ = upper_attr # this will affect all classes in the module

class Foo(): # global __metaclass__ won't work with "object" though
    # but we can define __metaclass__ here instead to affect only this class
    # and this will work with "object" children
    bar = 'bip'

Let's check:

>>> hasattr(Foo, 'bar')
False
>>> hasattr(Foo, 'BAR')
True
>>> Foo.BAR
'bip'

Now, let's do exactly the same, but using a real class for a metaclass:

# remember that `type` is actually a class like `str` and `int`
# so you can inherit from it
class UpperAttrMetaclass(type):
    # __new__ is the method called before __init__
    # it's the method that creates the object and returns it
    # while __init__ just initializes the object passed as parameter
    # you rarely use __new__, except when you want to control how the object
    # is created.
    # here the created object is the class, and we want to customize it
    # so we override __new__
    # you can do some stuff in __init__ too if you wish
    # some advanced use involves overriding __call__ as well, but we won't
    # see this
    def __new__(upperattr_metaclass, future_class_name,
                future_class_parents, future_class_attrs):
        uppercase_attrs = {
            attr if attr.startswith("__") else attr.upper(): v
            for attr, v in future_class_attrs.items()
        }
        return type(future_class_name, future_class_parents, uppercase_attrs)

Let's rewrite the above, but with shorter and more realistic variable names now that we know what they mean:

class UpperAttrMetaclass(type):
    def __new__(cls, clsname, bases, attrs):
        uppercase_attrs = {
            attr if attr.startswith("__") else attr.upper(): v
            for attr, v in attrs.items()
        }
        return type(clsname, bases, uppercase_attrs)

You may have noticed the extra argument cls. There is nothing special about it: __new__ always receives the class it's defined in, as the first parameter. Just like you have self for ordinary methods which receive the instance as the first parameter, or the defining class for class methods.

But this is not proper OOP. We are calling type directly and we aren't overriding or calling the parent's __new__. Let's do that instead:

class UpperAttrMetaclass(type):
    def __new__(cls, clsname, bases, attrs):
        uppercase_attrs = {
            attr if attr.startswith("__") else attr.upper(): v
            for attr, v in attrs.items()
        }
        return type.__new__(cls, clsname, bases, uppercase_attrs)

We can make it even cleaner by using super, which will ease inheritance (because yes, you can have metaclasses, inheriting from metaclasses, inheriting from type):

class UpperAttrMetaclass(type):
    def __new__(cls, clsname, bases, attrs):
        uppercase_attrs = {
            attr if attr.startswith("__") else attr.upper(): v
            for attr, v in attrs.items()
        }
        return super(UpperAttrMetaclass, cls).__new__(
            cls, clsname, bases, uppercase_attrs)

Oh, and in python 3 if you do this call with keyword arguments, like this:

class Foo(object, metaclass=MyMetaclass, kwarg1=value1):
    ...

It translates to this in the metaclass to use it:

class MyMetaclass(type):
    def __new__(cls, clsname, bases, dct, kwargs1=default):
        ...

That's it. There is really nothing more about metaclasses.

The reason behind the complexity of the code using metaclasses is not because of metaclasses, it's because you usually use metaclasses to do twisted stuff relying on introspection, manipulating inheritance, vars such as __dict__, etc.

Indeed, metaclasses are especially useful to do black magic, and therefore complicated stuff. But by themselves, they are simple:

  • intercept a class creation
  • modify the class
  • return the modified class

Why would you use metaclasses classes instead of functions?

Since __metaclass__ can accept any callable, why would you use a class since it's obviously more complicated?

There are several reasons to do so:

  • The intention is clear. When you read UpperAttrMetaclass(type), you know what's going to follow
  • You can use OOP. Metaclass can inherit from metaclass, override parent methods. Metaclasses can even use metaclasses.
  • Subclasses of a class will be instances of its metaclass if you specified a metaclass-class, but not with a metaclass-function.
  • You can structure your code better. You never use metaclasses for something as trivial as the above example. It's usually for something complicated. Having the ability to make several methods and group them in one class is very useful to make the code easier to read.
  • You can hook on __new__, __init__ and __call__. Which will allow you to do different stuff, Even if usually you can do it all in __new__, some people are just more comfortable using __init__.
  • These are called metaclasses, damn it! It must mean something!

Why would you use metaclasses?

Now the big question. Why would you use some obscure error-prone feature?

Well, usually you don't:

Metaclasses are deeper magic that 99% of users should never worry about it. If you wonder whether you need them, you don't (the people who actually need them to know with certainty that they need them and don't need an explanation about why).

Python Guru Tim Peters

The main use case for a metaclass is creating an API. A typical example of this is the Django ORM. It allows you to define something like this:

class Person(models.Model):
    name = models.CharField(max_length=30)
    age = models.IntegerField()

But if you do this:

person = Person(name='bob', age='35')
print(person.age)

It won't return an IntegerField object. It will return an int, and can even take it directly from the database.

This is possible because models.Model defines __metaclass__ and it uses some magic that will turn the Person you just defined with simple statements into a complex hook to a database field.

Django makes something complex look simple by exposing a simple API and using metaclasses, recreating code from this API to do the real job behind the scenes.

The last word

First, you know that classes are objects that can create instances.

Well, in fact, classes are themselves instances. Of metaclasses.

>>> class Foo(object): pass
>>> id(Foo)
142630324

Everything is an object in Python, and they are all either instance of classes or instances of metaclasses.

Except for type.

type is actually its own metaclass. This is not something you could reproduce in pure Python, and is done by cheating a little bit at the implementation level.

Secondly, metaclasses are complicated. You may not want to use them for very simple class alterations. You can change classes by using two different techniques:

99% of the time you need class alteration, you are better off using these.

But 98% of the time, you don't need class alteration at all.

Vue - Deep watching an array of objects and calculating the change?

Your comparison function between old value and new value is having some issue. It is better not to complicate things so much, as it will increase your debugging effort later. You should keep it simple.

The best way is to create a person-component and watch every person separately inside its own component, as shown below:

<person-component :person="person" v-for="person in people"></person-component>

Please find below a working example for watching inside person component. If you want to handle it on parent side, you may use $emit to send an event upwards, containing the id of modified person.

_x000D_
_x000D_
Vue.component('person-component', {_x000D_
    props: ["person"],_x000D_
    template: `_x000D_
        <div class="person">_x000D_
            {{person.name}}_x000D_
            <input type='text' v-model='person.age'/>_x000D_
        </div>`,_x000D_
    watch: {_x000D_
        person: {_x000D_
            handler: function(newValue) {_x000D_
                console.log("Person with ID:" + newValue.id + " modified")_x000D_
                console.log("New age: " + newValue.age)_x000D_
            },_x000D_
            deep: true_x000D_
        }_x000D_
    }_x000D_
});_x000D_
_x000D_
new Vue({_x000D_
    el: '#app',_x000D_
    data: {_x000D_
        people: [_x000D_
          {id: 0, name: 'Bob', age: 27},_x000D_
          {id: 1, name: 'Frank', age: 32},_x000D_
          {id: 2, name: 'Joe', age: 38}_x000D_
        ]_x000D_
    }_x000D_
});
_x000D_
<script src="https://unpkg.com/[email protected]/dist/vue.js"></script>_x000D_
<body>_x000D_
    <div id="app">_x000D_
        <p>List of people:</p>_x000D_
        <person-component :person="person" v-for="person in people"></person-component>_x000D_
    </div>_x000D_
</body>
_x000D_
_x000D_
_x000D_

How to get rows count of internal table in abap?

if I understand your question correctly, you want to know the row number during a conditional loop over an internal table. You can use the system variable sy-tabix if you work with internal tables. Please refer to the ABAP documentation if you need more information (especially the chapter on internal table processing).

Example:

LOOP AT itab INTO workarea
        WHERE tablefield = value.

     WRITE: 'This is row number ', sy-tabix.

ENDLOOP.

Difference between maven scope compile and provided for JAR packaging

If jar file is like executable spring boot jar file then scope of all dependencies must be compile to include all jar files.

But if jar file used in other packages or applications then it does not need to include all dependencies in jar file because these packages or applications can provide other dependencies themselves.

Removing a non empty directory programmatically in C or C++

//======================================================
// Recursely Delete files using:
//   Gnome-Glib & C++11
//======================================================

#include <iostream>
#include <string>
#include <glib.h>
#include <glib/gstdio.h>

using namespace std;

int DirDelete(const string& path)
{
   const gchar*    p;
   GError*   gerr;
   GDir*     d;
   int       r;
   string    ps;
   string    path_i;
   cout << "open:" << path << "\n";
   d        = g_dir_open(path.c_str(), 0, &gerr);
   r        = -1;

   if (d) {
      r = 0;

      while (!r && (p=g_dir_read_name(d))) {
          ps = string{p};
          if (ps == "." || ps == "..") {
            continue;
          }

          path_i = path + string{"/"} + p;


          if (g_file_test(path_i.c_str(), G_FILE_TEST_IS_DIR) != 0) {
            cout << "recurse:" << path_i << "\n";
            r = DirDelete(path_i);
          }
          else {
            cout << "unlink:" << path_i << "\n";
            r = g_unlink(path_i.c_str());
          }
      }

      g_dir_close(d);
   }

   if (r == 0) {
      r = g_rmdir(path.c_str());
     cout << "rmdir:" << path << "\n";

   }

   return r;
}

How to access ssis package variables inside script component

  • On the front properties page of the variable script, amend the ReadOnlyVariables (or ReadWriteVariables) property and select the variables you are interested in. This will enable the selected variables within the script task
  • Within code you will now have access to read the variable as

    string myString = Variables.MyVariableName.ToString();

positional argument follows keyword argument

The grammar of the language specifies that positional arguments appear before keyword or starred arguments in calls:

argument_list        ::=  positional_arguments ["," starred_and_keywords]
                            ["," keywords_arguments]
                          | starred_and_keywords ["," keywords_arguments]
                          | keywords_arguments

Specifically, a keyword argument looks like this: tag='insider trading!' while a positional argument looks like this: ..., exchange, .... The problem lies in that you appear to have copy/pasted the parameter list, and left some of the default values in place, which makes them look like keyword arguments rather than positional ones. This is fine, except that you then go back to using positional arguments, which is a syntax error.

Also, when an argument has a default value, such as price=None, that means you don't have to provide it. If you don't provide it, it will use the default value instead.

To resolve this error, convert your later positional arguments into keyword arguments, or, if they have default values and you don't need to use them, simply don't specify them at all:

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity)

# Fully positional:
order_id = kite.order_place(self, exchange, tradingsymbol, transaction_type, quantity, price, product, order_type, validity, disclosed_quantity, trigger_price, squareoff_value, stoploss_value, trailing_stoploss, variety, tag)

# Some positional, some keyword (all keywords at end):

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity, tag='insider trading!')

How do I create a circle or square with just CSS - with a hollow center?

To my knowledge there is no cross-browser compatible way to make a circle with CSS & HTML only.

For the square I guess you could make a div with a border and a z-index higher than what you are putting it over. I don't understand why you would need to do this, when you could just put a border on the image or "something" itself.

If anyone else knows how to make a circle that is cross browser compatible with CSS & HTML only, I would love to hear about it!

@Caspar Kleijne border-radius does not work in IE8 or below, not sure about 9.

Uploading file using POST request in Node.js

An undocumented feature of the formData field that request implements is the ability to pass options to the form-data module it uses:

request({
  url: 'http://example.com',
  method: 'POST',
  formData: {
    'regularField': 'someValue',
    'regularFile': someFileStream,
    'customBufferFile': {
      value: fileBufferData,
      options: {
        filename: 'myfile.bin'
      }
    }
  }
}, handleResponse);

This is useful if you need to avoid calling requestObj.form() but need to upload a buffer as a file. The form-data module also accepts contentType (the MIME type) and knownLength options.

This change was added in October 2014 (so 2 months after this question was asked), so it should be safe to use now (in 2017+). This equates to version v2.46.0 or above of request.

Displaying unicode symbols in HTML

I know an answer has already been accepted, but wanted to point a few things out.

Setting the content-type and charset is obviously a good practice, doing it on the server is much better, because it ensures consistency across your application.

However, I would use UTF-8 only when the language of my application uses a lot of characters that are available only in the UTF-8 charset. If you want to show a unicode character or symbol in one of cases, you can do so without changing the charset of your page.

HTML renderers have always been able to display symbols which are not part of the encoding character set of the page, as long as you mention the symbol in its numeric character reference (NCR). Sounds weird but its true.

So, even if your html has a header that states it has an encoding of ansi or any of the iso charsets, you can display a check mark by using its html character reference, in decimal - &#10003; or in hex - &#x2713;

So its a little difficult to understand why you are facing this issue on your pages. Can you check if the NCR value is correct, this is a good reference http://www.fileformat.info/info/unicode/char/2713/index.htm

assembly to compare two numbers

The basic technique (on most modern systems) is to subtract the two numbers and then to check the sign bit of the result, i.e. see if the result is greater than/equal to/less than zero. In the assembly code instead of getting the result directly (into a register), you normally just branch depending on the state:

; Compare r1 and r2
    CMP $r1, $r2
    JLT lessthan
greater_or_equal:
    ; print "r1 >= r2" somehow
    JMP l1
lessthan:
    ; print "r1 < r2" somehow
l1:

How to change the background color of Action Bar's Option Menu in Android 4.2?

There is an easy way to change the colors in Actionbar Use ActionBar Generator and copy paste all file in your res folder and change your theme in Android.manifest file.

Binding multiple events to a listener (without JQuery)?

Some compact syntax that achieves the desired result, POJS:

   "mousemove touchmove".split(" ").forEach(function(e){
      window.addEventListener(e,mouseMoveHandler,false);
    });

Custom Cell Row Height setting in storyboard is not responding

The same problem occurred when working on XCode 9 using Swift 4.

Add AutoLayout for the UI elements inside the Cell and custom cell row height will work accordingly as specified.

How could I convert data from string to long in c#

You can create your own conversion function:

    static long ToLong(string lNumber)
    {
        if (string.IsNullOrEmpty(lNumber))
            throw new Exception("Not a number!");
        char[] chars = lNumber.ToCharArray();
        long result = 0;
        bool isNegative = lNumber[0] == '-';
        if (isNegative && lNumber.Length == 1)
            throw new Exception("- Is not a number!");

        for (int i = (isNegative ? 1:0); i < lNumber.Length; i++)
        {
            if (!Char.IsDigit(chars[i]))
            {
                if (chars[i] == '.' && i < lNumber.Length - 1 && Char.IsDigit(chars[i+1]))
                {
                    var firstDigit = chars[i + 1] - 48;
                    return (isNegative ? -1L:1L) * (result + ((firstDigit < 5) ? 0L : 1L));    
                }
                throw new InvalidCastException($" {lNumber} is not a valid number!");
            }
            result = result * 10 + ((long)chars[i] - 48L);
        }
        return (isNegative ? -1L:1L) * result;
    }

It can be improved further:

  • performance wise
  • make the validation stricter in the sense that it currently doesn't care if characters after first decimal aren't digits
  • specify rounding behavior as parameter for conversion function. it currently does rounding

Java :Add scroll into text area

After adding JTextArea into JScrollPane here:

scroll = new JScrollPane(display);

You don't need to add it again into other container like you do:

middlePanel.add(display);

Just remove that last line of code and it will work fine. Like this:

    middlePanel=new JPanel();
    middlePanel.setBorder(new TitledBorder(new EtchedBorder(), "Display Area"));

    // create the middle panel components

    display = new JTextArea(16, 58);
    display.setEditable(false); // set textArea non-editable
    scroll = new JScrollPane(display);
    scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);

    //Add Textarea in to middle panel
    middlePanel.add(scroll);

JScrollPane is just another container that places scrollbars around your component when its needed and also has its own layout. All you need to do when you want to wrap anything into a scroll just pass it into JScrollPane constructor:

new JScrollPane( myComponent ) 

or set view like this:

JScrollPane pane = new JScrollPane ();
pane.getViewport ().setView ( myComponent );

Additional:

Here is fully working example since you still did not get it working:

public static void main ( String[] args )
{
    JPanel middlePanel = new JPanel ();
    middlePanel.setBorder ( new TitledBorder ( new EtchedBorder (), "Display Area" ) );

    // create the middle panel components

    JTextArea display = new JTextArea ( 16, 58 );
    display.setEditable ( false ); // set textArea non-editable
    JScrollPane scroll = new JScrollPane ( display );
    scroll.setVerticalScrollBarPolicy ( ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS );

    //Add Textarea in to middle panel
    middlePanel.add ( scroll );

    // My code
    JFrame frame = new JFrame ();
    frame.add ( middlePanel );
    frame.pack ();
    frame.setLocationRelativeTo ( null );
    frame.setVisible ( true );
}

And here is what you get: enter image description here

Make a URL-encoded POST request using `http.NewRequest(...)`

URL-encoded payload must be provided on the body parameter of the http.NewRequest(method, urlStr string, body io.Reader) method, as a type that implements io.Reader interface.

Based on the sample code:

package main

import (
    "fmt"
    "net/http"
    "net/url"
    "strconv"
    "strings"
)

func main() {
    apiUrl := "https://api.com"
    resource := "/user/"
    data := url.Values{}
    data.Set("name", "foo")
    data.Set("surname", "bar")

    u, _ := url.ParseRequestURI(apiUrl)
    u.Path = resource
    urlStr := u.String() // "https://api.com/user/"

    client := &http.Client{}
    r, _ := http.NewRequest(http.MethodPost, urlStr, strings.NewReader(data.Encode())) // URL-encoded payload
    r.Header.Add("Authorization", "auth_token=\"XXXXXXX\"")
    r.Header.Add("Content-Type", "application/x-www-form-urlencoded")
    r.Header.Add("Content-Length", strconv.Itoa(len(data.Encode())))

    resp, _ := client.Do(r)
    fmt.Println(resp.Status)
}

resp.Status is 200 OK this way.

Uncaught ReferenceError: angular is not defined - AngularJS not working

As you know angular.module( declared under angular.js file.So before accessing angular.module, you must have make it available by using <script src="lib/angular/angular.js"></script>(In your case) after then you can call angular.module. It will work.

like

<html lang="en">
<head>
  <meta charset="utf-8">
  <title>My AngularJS App</title>
  <link rel="stylesheet" href="css/app.css"/>
<!-- In production use:
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
  -->
  <script src="lib/angular/angular.js"></script>
  <script src="lib/angular/angular-route.js"></script>
  <script src="js/app.js"></script>
  <script src="js/services.js"></script>
  <script src="js/controllers.js"></script>
  <script src="js/filters.js"></script>
  <script src="js/directives.js"></script>

    <script>
        var app = angular.module('myApp',[]);

        app.directive('myDirective',function(){

            return function(scope, element,attrs) {
                element.bind('click',function() {alert('click')});
            };

        });
    </script>
</head>
<body ng-app="myApp">
    <div >
        <button my-directive>Click Me!</button>
    </div>
    <h1>{{2+3}}</h1>

</body>
</html>

Escape dot in a regex range

Because the dot is inside character class (square brackets []).

Take a look at http://www.regular-expressions.info/reference.html, it says (under char class section):

Any character except ^-]\ add that character to the possible matches for the character class.

passing argument to DialogFragment

In my case, none of the code above with bundle-operate works; Here is my decision (I don't know if it is proper code or not, but it works in my case):

public class DialogMessageType extends DialogFragment {
    private static String bodyText;

    public static DialogMessageType addSomeString(String temp){
        DialogMessageType f = new DialogMessageType();
        bodyText = temp;
        return f;
    };

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        final String[] choiseArray = {"sms", "email"};
        String title = "Send text via:";
        final AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setTitle(title).setItems(choiseArray, itemClickListener);
        builder.setCancelable(true);
        return builder.create();
    }

    DialogInterface.OnClickListener itemClickListener = new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            switch (which){
                case 0:
                    prepareToSendCoordsViaSMS(bodyText);
                    dialog.dismiss();
                    break;
                case 1:
                    prepareToSendCoordsViaEmail(bodyText);
                    dialog.dismiss();
                    break;
                default:
                    break;
            }
        }
    };
[...]
}

public class SendObjectActivity extends FragmentActivity {
[...]

DialogMessageType dialogMessageType = DialogMessageType.addSomeString(stringToSend);
dialogMessageType.show(getSupportFragmentManager(),"dialogMessageType");

[...]
}

Find elements inside forms and iframe using Java and Selenium WebDriver

Before you try searching for the elements within the iframe you will have to switch Selenium focus to the iframe.

Try this before searching for the elements within the iframe:

driver.switchTo().frame(driver.findElement(By.name("iFrameTitle")));

How do I prevent a Gateway Timeout with FastCGI on Nginx

Proxy timeouts are well, for proxies, not for FastCGI...

The directives that affect FastCGI timeouts are client_header_timeout, client_body_timeout and send_timeout.

Edit: Considering what's found on nginx wiki, the send_timeout directive is responsible for setting general timeout of response (which was bit misleading). For FastCGI there's fastcgi_read_timeout which is affecting the fastcgi process response timeout.

HTH.

Understanding Popen.communicate

Do not use communicate(input=""). It writes input to the process, closes its stdin and then reads all output.

Do it like this:

p=subprocess.Popen(["python","1st.py"],stdin=PIPE,stdout=PIPE)

# get output from process "Something to print"
one_line_output = p.stdout.readline()

# write 'a line\n' to the process
p.stdin.write('a line\n')

# get output from process "not time to break"
one_line_output = p.stdout.readline() 

# write "n\n" to that process for if r=='n':
p.stdin.write('n\n') 

# read the last output from the process  "Exiting"
one_line_output = p.stdout.readline()

What you would do to remove the error:

all_the_process_will_tell_you = p.communicate('all you will ever say to this process\nn\n')[0]

But since communicate closes the stdout and stdin and stderr, you can not read or write after you called communicate.

How to extract a string using JavaScript Regex?

this is how you can parse iCal files with javascript

    function calParse(str) {

        function parse() {
            var obj = {};
            while(str.length) {
                var p = str.shift().split(":");
                var k = p.shift(), p = p.join();
                switch(k) {
                    case "BEGIN":
                        obj[p] = parse();
                        break;
                    case "END":
                        return obj;
                    default:
                        obj[k] = p;
                }
            }
            return obj;
        }
        str = str.replace(/\n /g, " ").split("\n");
        return parse().VCALENDAR;
    }

    example = 
    'BEGIN:VCALENDAR\n'+
    'VERSION:2.0\n'+
    'PRODID:-//hacksw/handcal//NONSGML v1.0//EN\n'+
    'BEGIN:VEVENT\n'+
    'DTSTART:19970714T170000Z\n'+
    'DTEND:19970715T035959Z\n'+
    'SUMMARY:Bastille Day Party\n'+
    'END:VEVENT\n'+
    'END:VCALENDAR\n'


    cal = calParse(example);
    alert(cal.VEVENT.SUMMARY);

How to get the last five characters of a string using Substring() in C#?

Here is a quick extension method you can use that mimics PHP syntax. Include AssemblyName.Extensions to the code file you are using the extension in.

Then you could call:

input.SubstringReverse(-5) and it will return "Three".

namespace AssemblyName.Extensions {

    public static class StringExtensions
    {
        /// <summary>
        /// Takes a negative integer - counts back from the end of the string.
        /// </summary>
        /// <param name="str"></param>
        /// <param name="length"></param>
        public static string SubstringReverse(this string str, int length)
        {
            if (length > 0) 
            {
                throw new ArgumentOutOfRangeException("Length must be less than zero.");
            }

            if (str.Length < Math.Abs(length))
            {
                throw new ArgumentOutOfRangeException("Length cannot be greater than the length of the string.");
            }

            return str.Substring((str.Length + length), Math.Abs(length));
        }
    }
}

How to resolve the "ADB server didn't ACK" error?

For me it didn't work , it was related to a path problem happened after android studio 2.0 preview 1, I needed to update genymotion and virtual box, and apparently they tried to use same port for adb.

Solution is explained here link! Basically you just need to:

1) open genymotion settings

2) specify sdk path for the adb manually

3) adb kill-server

4) adb start-server

Using getline() with file input in C++

getline, as it name states, read a whole line, or at least till a delimiter that can be specified.

So the answer is "no", getlinedoes not match your need.

But you can do something like:

inFile >> first_name >> last_name >> age;
name = first_name + " " + last_name;

How do I finish the merge after resolving my merge conflicts?

How do I finish the merge after resolving my merge conflicts?

With Git 2.12 (Q1 2017), you will have the more natural command:

git merge --continue

See commit c7d227d (15 Dec 2016) by Jeff King (peff).
See commit 042e290, commit c261a87, commit 367ff69 (14 Dec 2016) by Chris Packham (cpackham).
(Merged by Junio C Hamano -- gitster -- in commit 05f6e1b, 27 Dec 2016)

See 2.12 release notes.

merge: add '--continue' option as a synonym for 'git commit'

Teach 'git merge' the --continue option which allows 'continuing' a merge by completing it.
The traditional way of completing a merge after resolving conflicts is to use 'git commit'.
Now with commands like 'git rebase' and 'git cherry-pick' having a '--continue' option adding such an option to 'git merge' presents a consistent UI.

How to get value from form field in django framework?

I use django 1.7+ and python 2.7+, the solution above dose not work. And the input value in the form can be got use POST as below (use the same form above):

if form.is_valid():
  data = request.POST.get('my_form_field_name')
  print data

Hope this helps.

How can I override inline styles with external CSS?

inline-styles in a document have the highest priority, so for example say if you want to change the color of a div element to blue, but you've an inline style with a color property set to red

<div style="font-size: 18px; color: red;">
   Hello World, How Can I Change The Color To Blue?
</div>
div {
   color: blue; 
   /* This Won't Work, As Inline Styles Have Color Red And As 
      Inline Styles Have Highest Priority, We Cannot Over Ride 
      The Color Using An Element Selector */
}

So, Should I Use jQuery/Javascript? - Answer Is NO

We can use element-attr CSS Selector with !important, note, !important is important here, else it won't over ride the inline styles..

<div style="font-size: 30px; color: red;">
    This is a test to see whether the inline styles can be over ridden with CSS?
</div>
div[style] {
   font-size: 12px !important;
   color: blue !important;
}

Demo

Note: Using !important ONLY will work here, but I've used div[style] selector to specifically select div having style attribute

How to download Google Play Services in an Android emulator?

To the latest setup and information if you have installed the Android Studio (i.e. 1.5) and trying to target SDK 4.0 then you may not be able to locate and setup the and AVD Emulator with SDK-vX.XX (with Google API's).

See following steps in order to download the required library and start with that. AVD Emulator setup -setting up Emulator for SDK4.0 with GoogleAPI so Map application can work- In Android Studio

But unfortunately above method did not work well on my side. And was not able to created Emulator with API Level 17 (SDK 4.2). So I followed this post that worked on my side well. The reason seems that the Android Studio Emulator creation window has limited options/features.

Google Play Services in emulator, implementing Google Plus login button etc

<Django object > is not JSON serializable

The easiest way is to use a JsonResponse.

For a queryset, you should pass a list of the the values for that queryset, like so:

from django.http import JsonResponse

queryset = YourModel.objects.filter(some__filter="some value").values()
return JsonResponse({"models_to_return": list(queryset)})

Static methods in Python?

Python Static methods can be created in two ways.

  1. Using staticmethod()

    class Arithmetic:
        def add(x, y):
            return x + y
    # create add static method
    Arithmetic.add = staticmethod(Arithmetic.add)
    
    print('Result:', Arithmetic.add(15, 10))
    

Output:

Result: 25

  1. Using @staticmethod

    class Arithmetic:
    
    # create add static method
    @staticmethod
    def add(x, y):
        return x + y
    
    print('Result:', Arithmetic.add(15, 10))
    

Output:

Result: 25

What are rvalues, lvalues, xvalues, glvalues, and prvalues?

I guess this document might serve as a not so short introduction : n3055

The whole massacre began with the move semantics. Once we have expressions that can be moved and not copied, suddenly easy to grasp rules demanded distinction between expressions that can be moved, and in which direction.

From what I guess based on the draft, the r/l value distinction stays the same, only in the context of moving things get messy.

Are they needed? Probably not if we wish to forfeit the new features. But to allow better optimization we should probably embrace them.

Quoting n3055:

  • An lvalue (so-called, historically, because lvalues could appear on the left-hand side of an assignment expression) designates a function or an object. [Example: If E is an expression of pointer type, then *E is an lvalue expression referring to the object or function to which E points. As another example, the result of calling a function whose return type is an lvalue reference is an lvalue.]
  • An xvalue (an “eXpiring” value) also refers to an object, usually near the end of its lifetime (so that its resources may be moved, for example). An xvalue is the result of certain kinds of expressions involving rvalue references. [Example: The result of calling a function whose return type is an rvalue reference is an xvalue.]
  • A glvalue (“generalized” lvalue) is an lvalue or an xvalue.
  • An rvalue (so-called, historically, because rvalues could appear on the right-hand side of an assignment expression) is an xvalue, a temporary object or subobject thereof, or a value that is not associated with an object.
  • A prvalue (“pure” rvalue) is an rvalue that is not an xvalue. [Example: The result of calling a function whose return type is not a reference is a prvalue]

The document in question is a great reference for this question, because it shows the exact changes in the standard that have happened as a result of the introduction of the new nomenclature.

MAC addresses in JavaScript

The quick and simple answer is No.

Javascript is quite a high level language and does not have access to this sort of information.

How to extract base URL from a string in JavaScript?

Edit: Some complain that it doesn't take into account protocol. So I decided to upgrade the code, since it is marked as answer. For those who like one-line-code... well sorry this why we use code minimizers, code should be human readable and this way is better... in my opinion.

var pathArray = "https://somedomain.com".split( '/' );
var protocol = pathArray[0];
var host = pathArray[2];
var url = protocol + '//' + host;

Or use Davids solution from below.

Is there a kind of Firebug or JavaScript console debug for Android?

I installed console add-on of the firefox (https://addons.mozilla.org/en-US/android/addon/console/) on my firefox browser on android and it worked quite well. Helped me debug my angular2 app.

Python: SyntaxError: non-keyword after keyword arg

To really get this clear, here's my for-beginners answer: You inputed the arguments in the wrong order.
A keyword argument has this style:

nullable=True, unique=False

A fixed parameter should be defined: True, False, etc. A non-keyword argument is different:

name="Ricardo", fruit="chontaduro" 

This syntax error asks you to first put name="Ricardo" and all of its kind (non-keyword) before those like nullable=True.

'cannot find or open the pdb file' Visual Studio C++ 2013

It worked for me. Go to Tools-> Options -> Debugger -> Native and check the Load DLL exports. Hope this helps

How to define Gradle's home in IDEA?

In case you are using Mac, most probably your gradle home should be /usr/local/gradle-2.0 for example.

In preference of IDEA search for gradle and set gradle home as given above. It should work

Playing a video in VideoView in Android

Add android.permission.READ_EXTERNAL_STORAGE in manifest, worked for me

Xcode stuck on Indexing

This happened to me. If you are using cocoapods do this:

  1. Delete project.xcworkspace
  2. Reinstall pods using 'pod install' on the terminal
  3. It will create a new project.xcworkspace
  4. Open the new project.xcworkspace -> Clean -> Build

Session only cookies with Javascript

Use the below code for a setup session cookie, it will work until browser close. (make sure not close tab)

function setCookie(cname, cvalue, exdays) {
    var d = new Date();
    d.setTime(d.getTime() + (exdays*24*60*60*1000));
    var expires = "expires="+ d.toUTCString();
    document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
  }
  function getCookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
    for(var i = 0; i <ca.length; i++) {
      var c = ca[i];
      while (c.charAt(0) == ' ') {
        c = c.substring(1);
      }
      if (c.indexOf(name) == 0) {
        return c.substring(name.length, c.length);
      }
    }
    return false;
  }
  
  
  if(getCookie("KoiMilGaya")) {
    //alert('found'); 
    // Cookie found. Display any text like repeat user. // reload, other page visit, close tab and open again.. 
  } else {
    //alert('nothing');
    // Display popup or anthing here. it shows on first visit only.  
    // this will load again when user closer browser and open again. 
    setCookie('KoiMilGaya','1');
  }

Table is marked as crashed and should be repaired

Connect to your server via SSH

then connect to your mysql console

and

USE user_base
REPAIR TABLE TABLE;

-OR-

If there are a lot of broken tables in current database:

mysqlcheck -uUSER -pPASSWORD  --repair --extended user_base

If there are a lot of broken tables in a lot of databases:

mysqlcheck -uUSER -pPASSWORD  --repair --extended -A

How/when to use ng-click to call a route?

just do it as follows in your html write:

<button ng-click="going()">goto</button>

And in your controller, add $state as follows:

.controller('homeCTRL', function($scope, **$state**) {

$scope.going = function(){

$state.go('your route');

}

})

Identifying Exception Type in a handler Catch Block

When dealing with situations where I don't exactly know what type of exception might come out of a method, a little "trick" I like to do is to recover the Exception's class name and add it to the error log so there is more information.

try
{
   <code>

} catch ( Exception caughtEx )
{
   throw new Exception("Unknown Exception Thrown: "
                       + "\n  Type:    " + caughtEx.GetType().Name
                       + "\n  Message: " + caughtEx.Message);
}

I do vouch for always handling Exceptions types individually, but the extra bit of info can be helpful, specially when dealing with code from people who love to capture catch-all generic types.

Using unset vs. setting a variable to empty

Based on the comments above, here is a simple test:

isunset() { [[ "${!1}" != 'x' ]] && [[ "${!1-x}" == 'x' ]] && echo 1; }
isset()   { [ -z "$(isunset "$1")" ] && echo 1; }

Example:

$ unset foo; [[ $(isunset foo) ]] && echo "It's unset" || echo "It's set"
It's unset
$ foo=     ; [[ $(isunset foo) ]] && echo "It's unset" || echo "It's set"
It's set
$ foo=bar  ; [[ $(isunset foo) ]] && echo "It's unset" || echo "It's set"
It's set

Laravel Query Builder where max id

Just like the docs say

DB::table('orders')->max('id');

Most efficient way to remove special characters from string

Well, unless you really need to squeeze the performance out of your function, just go with what is easiest to maintain and understand. A regular expression would look like this:

For additional performance, you can either pre-compile it or just tell it to compile on first call (subsequent calls will be faster.)

public static string RemoveSpecialCharacters(string str)
{
    return Regex.Replace(str, "[^a-zA-Z0-9_.]+", "", RegexOptions.Compiled);
}

How to open Android Device Monitor in latest Android Studio 3.1

According to developer docs, it's deprecated now. Please follow these docs: developer link

Create SQL identity as primary key?

This is similar to the scripts we generate on our team. Create the table first, then apply pk/fk and other constraints.

CREATE TABLE [dbo].[ImagenesUsuario] (
    [idImagen] [int] IDENTITY (1, 1) NOT NULL
)

ALTER TABLE [dbo].[ImagenesUsuario] ADD 
    CONSTRAINT [PK_ImagenesUsuario] PRIMARY KEY  CLUSTERED 
    (
        [idImagen]
    )  ON [PRIMARY] 

Fetch: POST json data

With ES2017 async/await support, this is how to POST a JSON payload:

_x000D_
_x000D_
(async () => {_x000D_
  const rawResponse = await fetch('https://httpbin.org/post', {_x000D_
    method: 'POST',_x000D_
    headers: {_x000D_
      'Accept': 'application/json',_x000D_
      'Content-Type': 'application/json'_x000D_
    },_x000D_
    body: JSON.stringify({a: 1, b: 'Textual content'})_x000D_
  });_x000D_
  const content = await rawResponse.json();_x000D_
_x000D_
  console.log(content);_x000D_
})();
_x000D_
_x000D_
_x000D_

Can't use ES2017? See @vp_art's answer using promises

The question however is asking for an issue caused by a long since fixed chrome bug.
Original answer follows.

chrome devtools doesn't even show the JSON as part of the request

This is the real issue here, and it's a bug with chrome devtools, fixed in Chrome 46.

That code works fine - it is POSTing the JSON correctly, it just cannot be seen.

I'd expect to see the object I've sent back

that's not working because that is not the correct format for JSfiddle's echo.

The correct code is:

var payload = {
    a: 1,
    b: 2
};

var data = new FormData();
data.append( "json", JSON.stringify( payload ) );

fetch("/echo/json/",
{
    method: "POST",
    body: data
})
.then(function(res){ return res.json(); })
.then(function(data){ alert( JSON.stringify( data ) ) })

For endpoints accepting JSON payloads, the original code is correct

SQLSTATE[HY000] [1045] Access denied for user 'root'@'localhost' (using password: YES) symfony2

I'm Using Xampp and Laravel 5.8 in Windows 10, and i've been like this before. When i got this problem, My XAMPP is no have Password Then I tried to delete some codes in config>database.php

'password' => env('DB_PASSWORD', ''),

And in .env

DB_PASSWORD=SECRET

the Problem is solved

C++ array initialization

You can declare the array in C++ in these type of ways. If you know the array size then you should declare the array for: integer: int myArray[array_size]; Double: double myArray[array_size]; Char and string : char myStringArray[array_size]; The difference between char and string is as follows

char myCharArray[6]={'a','b','c','d','e','f'};
char myStringArray[6]="abcdef";

If you don't know the size of array then you should leave the array blank like following.

integer: int myArray[array_size];

Double: double myArray[array_size];

Angular @ViewChild() error: Expected 2 arguments, but got 1

Regex for replacing all via IDEA (tested with Webstorm)

Find: \@ViewChild\('(.*)'\)

Replace: \@ViewChild\('$1', \{static: true\}\)

Trimming text strings in SQL Server 2008

I know this is an old question but I just found a solution which creates a user defined function using LTRIM and RTRIM. It does not handle double spaces in the middle of a string.

The solution is however straight forward:

User Defined Trim Function

character count using jquery

Use .length to count number of characters, and $.trim() function to remove spaces, and replace(/ /g,'') to replace multiple spaces with just one. Here is an example:

   var str = "      Hel  lo       ";
   console.log(str.length); 
   console.log($.trim(str).length); 
   console.log(str.replace(/ /g,'').length); 

Output:

20
7
5

Source: How to count number of characters in a string with JQuery

Automating running command on Linux from Windows using PuTTY

Try MtPutty, you can automate the ssh login in it. Its a great tool especially if you need to login to multiple servers many times. Try it here

Another tool worth trying is TeraTerm. Its really easy to use for the ssh automation stuff. You can get it here. But my favorite one is always MtPutty.

How to change or add theme to Android Studio?

Just a note for people in the future. To add more themes on a Mac, put the theme .icls files in

~/Library/Preferences/AndroidStudio/colors/

Then restart Android Studio. And select your new themes in

Android Studio > Preferences > Editor > Colors&Fonts

Android Studio can use any theme that are made for jetbrains IDE. Here is a good Github repo that has many themes for different IDEs.

Also, the Color Ide plugin is a good tool that changes the background colour of all menus in Android Studio to match your theme. Try it, the IDE will look much better.

Windows should have similar setups, just the theme directory will be a bit different, search for JetBrains Ide theme location should give you the result.

Error CS1705: "which has a higher version than referenced assembly"

One possible cause is that the second assembly is installed in GAC while the first assembly, with a higher version number, is added to the References of the project. To verify this, double click the assembly in the project references, and check if there is another assembly with the same name in the Object Browser.

If that is the case, use the gacutil.exe utility to uninstall the second assembly from the GAC. For example, if these are 64-bit assemblies:

C:\Program Files\Microsoft SDKs\Windows\v6.0A\Bin\x64\gacutil.exe -u <assembly_name>

Trigger change() event when setting <select>'s value with val() function

As jQuery won't trigger native change event but only triggers its own change event. If you bind event without jQuery and then use jQuery to trigger it the callbacks you bound won't run !

The solution is then like below (100% working) :

var sortBySelect = document.querySelector("select.your-class"); 
sortBySelect.value = "new value"; 
sortBySelect.dispatchEvent(new Event("change"));

how to set imageview src?

To set image cource in imageview you can use any of the following ways. First confirm your image is present in which format.

If you have image in the form of bitmap then use

imageview.setImageBitmap(bm);

If you have image in the form of drawable then use

imageview.setImageDrawable(drawable);

If you have image in your resource example if image is present in drawable folder then use

imageview.setImageResource(R.drawable.image);

If you have path of image then use

imageview.setImageURI(Uri.parse("pathofimage"));

merge two object arrays with Angular 2 and TypeScript?

You can also use the form recommended by ES6:

data => {
  this.results = [
    ...this.results,
    data.results,
  ];
  this._next = data.next;
},

This works if you initialize your array first (public results = [];); otherwise replace ...this.results, by ...this.results ? this.results : [],.

Hope this helps

How to get relative path of a file in visual studio?

When it is the case that you want to use any kind of external file, there is certainly a way to put them in a folder within your project, but not as valid as getting them from resources. In a regular Visual Studio project, you should have a Resources.resx file under the Properties section, if not, you can easily add your own Resource.resx file. And add any kind of file in it, you can reach the walkthrough for adding resource files to your project here.

After having resource files in your project, calling them is easy as this:

var myIcon = Resources.MyIconFile;

Of course you should add the using Properties statement like this:

using <namespace>.Properties;

Display a loading bar before the entire page is loaded

Whenever you try to load any data in this window this gif will load.

HTML

Make a Div

<div class="loader"></div>

CSS .

.loader {
    position: fixed;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    z-index: 9999;
    background: url('https://lkp.dispendik.surabaya.go.id/assets/loading.gif') 50% 50% no-repeat rgb(249,249,249);

jQuery

$(window).load(function() {
        $(".loader").fadeOut("slow");
});
<script src="https://code.jquery.com/jquery-1.9.1.min.js"></script>

enter image description here

Selecting an element in iFrame jQuery

If the case is accessing the IFrame via console, e. g. Chrome Dev Tools then you can just select the context of DOM requests via dropdown (see the picture).

Chrome Dev Tools - Selecting the iFrame

@Autowired - No qualifying bean of type found for dependency at least 1 bean

In your controller class, just add @ComponentScan("package") annotation. In my case the package name is com.shoppingcart.So i wrote the code as @ComponentScan("com.shoppingcart") and it worked for me.

The entity type <type> is not part of the model for the current context

Sounds obvious, but make sure that you are not explicitly ignoring the type:

modelBuilder.Ignore<MyType>();

Most efficient way to check for DBNull and then assign to a variable?

This is how I handle reading from DataRows

///<summary>
/// Handles operations for Enumerations
///</summary>
public static class DataRowUserExtensions
{
    /// <summary>
    /// Gets the specified data row.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="dataRow">The data row.</param>
    /// <param name="key">The key.</param>
    /// <returns></returns>
    public static T Get<T>(this DataRow dataRow, string key)
    {
        return (T) ChangeTypeTo<T>(dataRow[key]);
    }

    private static object ChangeTypeTo<T>(this object value)
    {
        Type underlyingType = typeof (T);
        if (underlyingType == null)
            throw new ArgumentNullException("value");

        if (underlyingType.IsGenericType && underlyingType.GetGenericTypeDefinition().Equals(typeof (Nullable<>)))
        {
            if (value == null)
                return null;
            var converter = new NullableConverter(underlyingType);
            underlyingType = converter.UnderlyingType;
        }

        // Try changing to Guid  
        if (underlyingType == typeof (Guid))
        {
            try
            {
                return new Guid(value.ToString());
            }
            catch

            {
                return null;
            }
        }
        return Convert.ChangeType(value, underlyingType);
    }
}

Usage example:

if (dbRow.Get<int>("Type") == 1)
{
    newNode = new TreeViewNode
                  {
                      ToolTip = dbRow.Get<string>("Name"),
                      Text = (dbRow.Get<string>("Name").Length > 25 ? dbRow.Get<string>("Name").Substring(0, 25) + "..." : dbRow.Get<string>("Name")),
                      ImageUrl = "file.gif",
                      ID = dbRow.Get<string>("ReportPath"),
                      Value = dbRow.Get<string>("ReportDescription").Replace("'", "\'"),
                      NavigateUrl = ("?ReportType=" + dbRow.Get<string>("ReportPath"))
                  };
}

Props to Monsters Got My .Net for ChageTypeTo code.

mysql update multiple columns with same now()

Found a solution:

mysql> UPDATE table SET last_update=now(), last_monitor=last_update WHERE id=1;

I found this in MySQL Docs and after a few tests it works:

the following statement sets col2 to the current (updated) col1 value, not the original col1 value. The result is that col1 and col2 have the same value. This behavior differs from standard SQL.

UPDATE t1 SET col1 = col1 + 1, col2 = col1;

Getting "error": "unsupported_grant_type" when trying to get a JWT by calling an OWIN OAuth secured Web Api via Postman

If you are using AngularJS you need to pass the body params as string:

    factory.getToken = function(person_username) {
    console.log('Getting DI Token');
    var url = diUrl + "/token";

    return $http({
        method: 'POST',
        url: url,
        data: 'grant_type=password&[email protected]&password=mypass',
        responseType:'json',
        headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
    });
};

javascript create array from for loop

You need to push i

var yearStart = 2000;
var yearEnd = 2040;

var arr = [];

for (var i = yearStart; i < yearEnd+1; i++) {
    arr.push(i);
}

Then, your resulting array will be:

arr = [2000, 2001, 2003, ... 2039, 2040]

Hope this helps

INSERT INTO from two different server database

You cannot directly copy a table into a destination server database from a different database if source db is not in your linked servers. But one way is possible that, generate scripts (schema with data) of the desired table into one table temporarily in the source server DB, then execute the script in the destination server DB to create a table with your data. Finally use INSERT INTO [DESTINATION_TABLE] select * from [TEMPORARY_SOURCE_TABLE]. After getting the data into your destination table drop the temporary one.

I found this solution when I faced the same situation. Hope this helps you too.

How to enumerate a range of numbers starting at 1

Ok, I feel a bit stupid here... what's the reason not to just do it with something like
[(a+1,b) for (a,b) in enumerate(r)] ? If you won't function, no problem either:

>>> r = range(2000, 2005)
>>> [(a+1,b) for (a,b) in enumerate(r)]
[(1, 2000), (2, 2001), (3, 2002), (4, 2003), (5, 2004)]

>>> enumerate1 = lambda r:((a+1,b) for (a,b) in enumerate(r)) 

>>> list(enumerate1(range(2000,2005)))   # note - generator just like original enumerate()
[(1, 2000), (2, 2001), (3, 2002), (4, 2003), (5, 2004)]

How to Call a Function inside a Render in React/Jsx

To call the function you have to add ()

{this.renderIcon()}   

What's the difference between SCSS and Sass?

The basic difference is the syntax. While SASS has a loose syntax with white space and no semicolons, the SCSS resembles more to CSS.

Query for array elements inside JSON type

jsonb in Postgres 9.4+

You can use the same query as below, just with jsonb_array_elements().

But rather use the jsonb "contains" operator @> in combination with a matching GIN index on the expression data->'objects':

CREATE INDEX reports_data_gin_idx ON reports
USING gin ((data->'objects') jsonb_path_ops);

SELECT * FROM reports WHERE data->'objects' @> '[{"src":"foo.png"}]';

Since the key objects holds a JSON array, we need to match the structure in the search term and wrap the array element into square brackets, too. Drop the array brackets when searching a plain record.

More explanation and options:

json in Postgres 9.3+

Unnest the JSON array with the function json_array_elements() in a lateral join in the FROM clause and test for its elements:

SELECT data::text, obj
FROM   reports r, json_array_elements(r.data#>'{objects}') obj
WHERE  obj->>'src' = 'foo.png';

db<>fiddle here
Old sqlfiddle

The CTE (WITH query) just substitutes for a table reports.
Or, equivalent for just a single level of nesting:

SELECT *
FROM   reports r, json_array_elements(r.data->'objects') obj
WHERE  obj->>'src' = 'foo.png';

->>, -> and #> operators are explained in the manual.

Both queries use an implicit JOIN LATERAL.

Closely related:

how to toggle attr() in jquery

I know this is old and answered but I recently had to implement this and decided to make 2 simple jQuery plugins that might help for those interested

usage:

// 1
$('.container').toggleAttr('aria-hidden', "true");
// 2
$('.container').toggleAttrVal('aria-hidden', "true", "false");

1 - Toggles the entire attribute regardless if the original value doesn't match the one you provided.

2 - Toggles the value of the attribute between the 2 provided values.

 // jquery toggle whole attribute
  $.fn.toggleAttr = function(attr, val) {
    var test = $(this).attr(attr);
    if ( test ) { 
      // if attrib exists with ANY value, still remove it
      $(this).removeAttr(attr);
    } else {
      $(this).attr(attr, val);
    }
    return this;
  };

  // jquery toggle just the attribute value
  $.fn.toggleAttrVal = function(attr, val1, val2) {
    var test = $(this).attr(attr);
    if ( test === val1) {
      $(this).attr(attr, val2);
      return this;
    }
    if ( test === val2) {
      $(this).attr(attr, val1);
      return this;
    }
    // default to val1 if neither
    $(this).attr(attr, val1);
    return this;
  };

This is how you would use it in the original example:

$(".list-toggle").click(function() {
    $(".list-sort").toggleAttr('colspan', 6);
});

How to initialize struct?

You use an implicit operator that converts the string value to a struct value:

public struct MyStruct {
  public string s;
  public int length;

  public static implicit operator MyStruct(string value) {
    return new MyStruct() { s = value, length = value.Length };
  }

}

Example:

MyStruct myStruct = "Lol";
Console.WriteLine(myStruct.s);
Console.WriteLine(myStruct.length);

Output:

Lol
3

How to change the color of header bar and address bar in newest Chrome version on Lollipop?

From the Official documentation,

For example, to set the background color to orange:

<meta name="theme-color" content="#db5945">

In addition, Chrome will show beautiful high-res favicons when they’re provided. Chrome for Android picks the highest res icon that you provide, and we recommend providing a 192×192px PNG file. For example:

<link rel="icon" sizes="192x192" href="nice-highres.png">

How do I create a user with the same privileges as root in MySQL/MariaDB?

% mysql --user=root mysql
CREATE USER 'monty'@'localhost' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost' WITH GRANT OPTION;
CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%' WITH GRANT OPTION;
CREATE USER 'admin'@'localhost';
GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost';
CREATE USER 'dummy'@'localhost';
FLUSH PRIVILEGES;

How to get an array of specific "key" in multidimensional array without looping

If id is the first key in the array, this'll do:

$ids = array_map('current', $users);

You should not necessarily rely on this though. :)

ORA-01008: not all variables bound. They are bound

On Charles' comment problem: to make things worse, let

:p1 = 'TRIALDEV'

via a Command Parameter, then execute

select T.table_name as NAME, COALESCE(C.comments, '===') as DESCRIPTION
from all_all_tables T
Inner Join all_tab_comments C on T.owner = C.owner and T.table_name = C.table_name
where Upper(T.owner)=:p1
order by T.table_name

558 line(s) affected. Processing time: 00:00:00.6535711

and when changing the literal string from === to ---

select T.table_name as NAME, COALESCE(C.comments, '---') as DESCRIPTION
[...from...same-as-above...]

ORA-01008: not all variables bound

Both statements execute fine in SQL Developer. The shortened code:

            Using con = New OracleConnection(cs)
                con.Open()
                Using cmd = con.CreateCommand()
                    cmd.CommandText = cmdText
                    cmd.Parameters.Add(pn, OracleDbType.NVarchar2, 250).Value = p
                    Dim tbl = New DataTable
                    Dim da = New OracleDataAdapter(cmd)
                    da.Fill(tbl)
                    Return tbl
                End Using
            End Using

using Oracle.ManagedDataAccess.dll Version 4.121.2.0 with the default settings in VS2015 on the .Net 4.61 platform.

So somewhere in the call chain, there might be a parser that is a bit too aggressively looking for one-line-comments started by -- in the commandText. But even if this would be true, the error message "not all variables bound" is at least misleading.

Is it possible to overwrite a function in PHP

Monkey patch in namespace php >= 5.3

A less evasive method than modifying the interpreter is the monkey patch.

Monkey patching is the art of replacing the actual implementation with a similar "patch" of your own.

Ninja skills

Before you can monkey patch like a PHP Ninja we first have to understand PHPs namespaces.

Since PHP 5.3 we got introduced to namespaces which you might at first glance denote to be equivalent to something like java packages perhaps, but it's not quite the same. Namespaces, in PHP, is a way to encapsulate scope by creating a hierarchy of focus, especially for functions and constants. As this topic, fallback to global functions, aims to explain.

If you don't provide a namespace when calling a function, PHP first looks in the current namespace then moves down the hierarchy until it finds the first function declared within that prefixed namespace and executes that. For our example if you are calling print_r(); from namespace My\Awesome\Namespace; What PHP does is to first look for a function called My\Awesome\Namespace\print_r(); then My\Awesome\print_r(); then My\print_r(); until it finds the PHP built in function in the global namespace \print_r();.

You will not be able to define a function print_r($object) {} in the global namespace because this will cause a name collision since a function with that name already exists.

Expect a fatal error to the likes of:

Fatal error: Cannot redeclare print_r()

But nothing stops you, however, from doing just that within the scope of a namespace.

Patching the monkey

Say you have a script using several print_r(); calls.

Example:

<?php
     print_r($some_object);
     // do some stuff
     print_r($another_object);
     // do some other stuff
     print_r($data_object);
     // do more stuff
     print_r($debug_object);

But you later change your mind and you want the output wrapped in <pre></pre> tags instead. Ever happened to you?

Before you go and change every call to print_r(); consider monkey patching instead.

Example:

<?php
    namespace MyNamespace {
        function print_r($object) 
        {
            echo "<pre>", \print_r($object, true), "</pre>"; 
        }

        print_r($some_object);
        // do some stuff
        print_r($another_object);
        // do some other stuff
        print_r($data_object);
        // do more stuff
        print_r($debug_object);
    }

Your script will now be using MyNamespace\print_r(); instead of the global \print_r();

Works great for mocking unit tests.

nJoy!

Python: Get the first character of the first string in a list?

Get the first character of a bare python string:

>>> mystring = "hello"
>>> print(mystring[0])
h
>>> print(mystring[:1])
h
>>> print(mystring[3])
l
>>> print(mystring[-1])
o
>>> print(mystring[2:3])
l
>>> print(mystring[2:4])
ll

Get the first character from a string in the first position of a python list:

>>> myarray = []
>>> myarray.append("blah")
>>> myarray[0][:1]
'b'
>>> myarray[0][-1]
'h'
>>> myarray[0][1:3]
'la'

Many people get tripped up here because they are mixing up operators of Python list objects and operators of Numpy ndarray objects:

Numpy operations are very different than python list operations.

Wrap your head around the two conflicting worlds of Python's "list slicing, indexing, subsetting" and then Numpy's "masking, slicing, subsetting, indexing, then numpy's enhanced fancy indexing".

These two videos cleared things up for me:

"Losing your Loops, Fast Numerical Computing with NumPy" by PyCon 2015: https://youtu.be/EEUXKG97YRw?t=22m22s

"NumPy Beginner | SciPy 2016 Tutorial" by Alexandre Chabot LeClerc: https://youtu.be/gtejJ3RCddE?t=1h24m54s

How to list imported modules?

Stealing from @Lila (couldn't make a comment because of no formatting), this shows the module's /path/, as well:

#!/usr/bin/env python
import sys
from modulefinder import ModuleFinder
finder = ModuleFinder()
# Pass the name of the python file of interest
finder.run_script(sys.argv[1])
# This is what's different from @Lila's script
finder.report()

which produces:

Name                      File
----                      ----

...
m token                     /opt/rh/rh-python35/root/usr/lib64/python3.5/token.py
m tokenize                  /opt/rh/rh-python35/root/usr/lib64/python3.5/tokenize.py
m traceback                 /opt/rh/rh-python35/root/usr/lib64/python3.5/traceback.py
...

.. suitable for grepping or what have you. Be warned, it's long!

What does \u003C mean?

It is a unicode char \u003C = <

default web page width - 1024px or 980px?

even there is no right or wrong answer for this question , but I personally prefer 960px width . since all modern monitors support at least 1024 × 768 pixel resolution. 960 is divisible by 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 64, 80, 96, 120, 160, 192, 240, 320 and 480. This makes it a highly flexible base number to work with.

see this article that shows most popular screens resolutions 2013-2014 in US and UK : http://www.hobo-web.co.uk/best-screen-size/

How does origin/HEAD get set?

Run the following commands from git CLI:

# move to the wanted commit
git reset --hard <commit-hash> 

# update remote
git push --force origin <branch-name> 

rails generate model

The code is okay but you are in the wrong directory. You must run these commands inside your rails project-directory.

The normal way to get there from scratch is:

$ rails new PROJECT_NAME
$ cd PROJECT_NAME
$ rails generate model ad \
    name:string \ 
    description:text \
    price:decimal \
    seller_id:integer \
    email:string img_url:string

No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API

In my case,I use the below solution

Front-end or Angular

post(
    this.serverUrl, dataObjToPost,
    {
      headers: new HttpHeaders({
           'Content-Type':  'application/json',
         })
    }
)

back-end (I use php)

header("Access-Control-Allow-Origin: http://localhost:4200");
header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
header("Access-Control-Allow-Headers: Content-Type, Authorization");

$postdata = file_get_contents("php://input");
$request = json_decode($postdata);
print_r($request);

Npm Error - No matching version found for

Try removing "package-lock.json" and running "npm install && npm update", it'll install the latest version and clear all errors.

Appending to an existing string

Yet an other way:

s.insert(-1, ' world')

How can I center <ul> <li> into div

If you know the width of the ul then you can simply set the margin of the ul to 0 auto;

This will align the ul in the middle of the containing div

Example:

HTML:

<div id="container">
 <ul>
  <li>Item1</li>
  <li>Item2</li>
 </ul>
<div>

CSS:

  #container ul{
    width:300px;
    margin:0 auto;
  }

How to remove item from a JavaScript object

_x000D_
_x000D_
var test = {'red':'#FF0000', 'blue':'#0000FF'};_x000D_
delete test.blue; // or use => delete test['blue'];_x000D_
console.log(test);
_x000D_
_x000D_
_x000D_

this deletes test.blue

How to count the number of occurrences of a character in an Oracle varchar value?

here is a solution that will function for both characters and substrings:

select (length('a') - nvl(length(replace('a','b')),0)) / length('b')
  from dual

where a is the string in which you search the occurrence of b

have a nice day!

Hive load CSV with commas in quoted fields

Add a backward slash in FIELDS TERMINATED BY '\;'

For Example:

CREATE  TABLE demo_table_1_csv
COMMENT 'my_csv_table 1'
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\;'
LINES TERMINATED BY '\n'
STORED AS TEXTFILE
LOCATION 'your_hdfs_path'
AS 
select a.tran_uuid,a.cust_id,a.risk_flag,a.lookback_start_date,a.lookback_end_date,b.scn_name,b.alerted_risk_category,
CASE WHEN (b.activity_id is not null ) THEN 1 ELSE 0 END as Alert_Flag 
FROM scn1_rcc1_agg as a LEFT OUTER JOIN scenario_activity_alert as b ON a.tran_uuid = b.activity_id;

I have tested it, and it worked.

How to obtain the location of cacerts of the default java installation?

Under Linux, to find the location of $JAVA_HOME:

readlink -f /usr/bin/java | sed "s:bin/java::"

the cacerts are under lib/security/cacerts:

$(readlink -f /usr/bin/java | sed "s:bin/java::")lib/security/cacerts

Under mac OS X , to find $JAVA_HOME run:

/usr/libexec/java_home

the cacerts are under Home/lib/security/cacerts:

$(/usr/libexec/java_home)/lib/security/cacerts

UPDATE (OS X with JDK)

above code was tested on computer without JDK installed. With JDK installed, as pR0Ps said, it's at

$(/usr/libexec/java_home)/jre/lib/security/cacerts

INSERT and UPDATE a record using cursors in oracle

This is a highly inefficient way of doing it. You can use the merge statement and then there's no need for cursors, looping or (if you can do without) PL/SQL.

MERGE INTO studLoad l
USING ( SELECT studId, studName FROM student ) s
ON (l.studId = s.studId)
WHEN MATCHED THEN
  UPDATE SET l.studName = s.studName
   WHERE l.studName != s.studName
WHEN NOT MATCHED THEN 
INSERT (l.studID, l.studName)
VALUES (s.studId, s.studName)

Make sure you commit, once completed, in order to be able to see this in the database.


To actually answer your question I would do it something like as follows. This has the benefit of doing most of the work in SQL and only updating based on the rowid, a unique address in the table.

It declares a type, which you place the data within in bulk, 10,000 rows at a time. Then processes these rows individually.

However, as I say this will not be as efficient as merge.

declare

   cursor c_data is
    select b.rowid as rid, a.studId, a.studName
      from student a
      left outer join studLoad b
        on a.studId = b.studId
       and a.studName <> b.studName
           ;

   type t__data is table of c_data%rowtype index by binary_integer;
   t_data t__data;

begin

   open c_data;
   loop
      fetch c_data bulk collect into t_data limit 10000;

      exit when t_data.count = 0;

      for idx in t_data.first .. t_data.last loop
         if t_data(idx).rid is null then
            insert into studLoad (studId, studName)
            values (t_data(idx).studId, t_data(idx).studName);
         else
            update studLoad
               set studName = t_data(idx).studName
             where rowid = t_data(idx).rid
                   ;
         end if;
      end loop;

   end loop;
   close c_data;

end;
/

How to set time to midnight for current day?

Most of the suggested solutions can cause a 1 day error depending on the time associated with each date. If you are looking for an integer number of calendar days between to dates, regardless of the time associated with each date, I have found that this works well:

return (dateOne.Value.Date - dateTwo.Value.Date).Days;

Update multiple rows using select statement

You can use alias to improve the query:

UPDATE t1
   SET t1.Value = t2.Value
  FROM table1 AS t1
         INNER JOIN 
       table2 AS t2
         ON t1.ID = t2.ID

Vertically align text to top within a UILabel

I riffed off dalewking's suggestion and added a UIEdgeInset to allow for an adjustable margin. nice work around.

- (id)init
{
    if (self = [super init]) {
        contentEdgeInsets = UIEdgeInsetsZero;
    }

    return self;
}

- (void)layoutSubviews
{
    CGRect localBounds = self.bounds;
    localBounds = CGRectMake(MAX(0, localBounds.origin.x + contentEdgeInsets.left), 
                             MAX(0, localBounds.origin.y + contentEdgeInsets.top), 
                             MIN(localBounds.size.width, localBounds.size.width - (contentEdgeInsets.left + contentEdgeInsets.right)), 
                             MIN(localBounds.size.height, localBounds.size.height - (contentEdgeInsets.top + contentEdgeInsets.bottom)));

    for (UIView *subview in self.subviews) {
        if ([subview isKindOfClass:[UILabel class]]) {
            UILabel *label = (UILabel*)subview;
            CGSize lineSize = [label.text sizeWithFont:label.font];
            CGSize sizeForText = [label.text sizeWithFont:label.font constrainedToSize:localBounds.size lineBreakMode:label.lineBreakMode];

            NSInteger numberOfLines = ceilf(sizeForText.height/lineSize.height);

            label.numberOfLines = numberOfLines;
            label.frame = CGRectMake(MAX(0, contentEdgeInsets.left), MAX(0, contentEdgeInsets.top), localBounds.size.width, MIN(localBounds.size.height, lineSize.height * numberOfLines)); 
        }
    }
}

JQuery - Get select value

val() returns the value of the <select> element, i.e. the value attribute of the selected <option> element.

Since you actually want the inner text of the selected <option> element, you should match that element and use text() instead:

var nationality = $("#dancerCountry option:selected").text();

How to temporarily exit Vim and go back

To extend user Zen's answer, you could add the following line in your ~/.vimrc file to allow quick toggling between Bash and Vim:

noremap <C-d> :sh<cr>

static linking only some libraries

There is also -l:libstatic1.a (minus l colon) variant of -l option in gcc which can be used to link static library (Thanks to https://stackoverflow.com/a/20728782). Is it documented? Not in the official documentation of gcc (which is not exact for shared libs too): https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html

-llibrary
-l library 

Search the library named library when linking. (The second alternative with the library as a separate argument is only for POSIX compliance and is not recommended.) ... The only difference between using an -l option and specifying a file name is that -l surrounds library with ‘lib’ and ‘.a’ and searches several directories.

The binutils ld doc describes it. The -lname option will do search for libname.so then for libname.a adding lib prefix and .so (if enabled at the moment) or .a suffix. But -l:name option will only search exactly for the name specified: https://sourceware.org/binutils/docs/ld/Options.html

-l namespec
--library=namespec

Add the archive or object file specified by namespec to the list of files to link. This option may be used any number of times. If namespec is of the form :filename, ld will search the library path for a file called filename, otherwise it will search the library path for a file called libnamespec.a.

On systems which support shared libraries, ld may also search for files other than libnamespec.a. Specifically, on ELF and SunOS systems, ld will search a directory for a library called libnamespec.so before searching for one called libnamespec.a. (By convention, a .so extension indicates a shared library.) Note that this behavior does not apply to :filename, which always specifies a file called filename.

The linker will search an archive only once, at the location where it is specified on the command line. If the archive defines a symbol which was undefined in some object which appeared before the archive on the command line, the linker will include the appropriate file(s) from the archive. However, an undefined symbol in an object appearing later on the command line will not cause the linker to search the archive again.

See the -( option for a way to force the linker to search archives multiple times.

You may list the same archive multiple times on the command line.

This type of archive searching is standard for Unix linkers. However, if you are using ld on AIX, note that it is different from the behaviour of the AIX linker.

The variant -l:namespec is documented since 2.18 version of binutils (2007): https://sourceware.org/binutils/docs-2.18/ld/Options.html

How to encrypt and decrypt file in Android?

You could use java-aes-crypto or Facebook's Conceal

java-aes-crypto

Quoting from the repo

A simple Android class for encrypting & decrypting strings, aiming to avoid the classic mistakes that most such classes suffer from.

Facebook's conceal

Quoting from the repo

Conceal provides easy Android APIs for performing fast encryption and authentication of data

What is the "double tilde" (~~) operator in JavaScript?

The diffrence is very simple:

Long version

If you want to have better readability, use Math.floor. But if you want to minimize it, use tilde ~~.

There are a lot of sources on the internet saying Math.floor is faster, but sometimes ~~. I would not recommend you think about speed because it is not going to be noticed when running the code. Maybe in tests etc, but no human can see a diffrence here. What would be faster is to use ~~ for a faster load time.

Short version

~~ is shorter/takes less space. Math.floor improves the readability. Sometimes tilde is faster, sometimes Math.floor is faster, but it is not noticeable.

Iterating through list of list in Python

This can also be achieved with itertools.chain.from_iterable which will flatten the consecutive iterables:

import itertools
for item in itertools.chain.from_iterable(iterables):
    # do something with item    

Using Selenium Web Driver to retrieve value of a HTML input

Following @ragzzy 's answer I use

 public static string Value(this IWebElement element, IJavaScriptExecutor javaScriptExecutor)
    {

        try
        {
            string value = javaScriptExecutor.ExecuteScript("return arguments[0].value", element) as string;
            return value;
        }
        catch (Exception)
        {
            return null;
        }
    }

It works quite well and does not alter the DOM

How do I import a Swift file from another Swift file?

Instead of requiring explicit imports, the Swift compiler implicitly searches for .swiftmodule files of dependency Swift libraries.

Xcode can build swift modules for you, or refer to the railsware blog for command line instructions for swiftc.

docker build with --build-arg with multiple arguments

The above answer by pl_rock is correct, the only thing I would add is to expect the ARG inside the Dockerfile if not you won't have access to it. So if you are doing

docker build -t essearch/ess-elasticsearch:1.7.6 --build-arg number_of_shards=5 --build-arg number_of_replicas=2 --no-cache .

Then inside the Dockerfile you should add

ARG number_of_replicas
ARG number_of_shards

I was running into this problem, so I hope I help someone (myself) in the future.

How can I prevent the textarea from stretching beyond his parent DIV element? (google-chrome issue only)

textarea {
width: 700px;  
height: 100px;
resize: none; }

assign your required width and height for the textarea and then use. resize: none ; css property which will disable the textarea's stretchable property.

How to align a div inside td element using CSS class

div { margin: auto; }

This will center your div.

Div by itself is a blockelement. Therefor you need to define the style to the div how to behave.

CSS file not refreshing in browser

Is this a local custom CSS file? Is this your website? Maybe you should clear your cache.

Also the last CSS declaration takes precedence.

How to get the html of a div on another page with jQuery ajax?

$.ajax({
  url:href,
  type:'get',
  success: function(data){
   console.log($(data)); 
  }
});

This console log gets an array like object: [meta, title, ,], very strange

You can use JavaScript:

var doc = document.documentElement.cloneNode()
doc.innerHTML = data
$content = $(doc.querySelector('#content'))

Gulp command not found after install

I got this working on Win10 using a combination of the answers from above and elsewhere. Posting here for others and future me.

I followed the instructions from here: https://gulpjs.com/docs/en/getting-started/quick-start but on the last step after typing gulp --version I got the message -bash: gulp: command not found

To fix this:

  1. I added %AppData%\npm to my Path environment variable
  2. Closed all gitbash (cmd, powershell, etc...) and restarted gitbash.
  3. Then gulp --version worked

Also, found the below for reasons why not to install gulp globally and how to remove it (not sure if this is advisable though):

what does gulp-"cli" stands for?

How to uninstall Gulp CLI from NPM globally?

Display fullscreen mode on Tkinter

This creates a fullscreen window. Pressing Escape resizes the window to '200x200+0+0' by default. If you move or resize the window, Escape toggles between the current geometry and the previous geometry.

import Tkinter as tk

class FullScreenApp(object):
    def __init__(self, master, **kwargs):
        self.master=master
        pad=3
        self._geom='200x200+0+0'
        master.geometry("{0}x{1}+0+0".format(
            master.winfo_screenwidth()-pad, master.winfo_screenheight()-pad))
        master.bind('<Escape>',self.toggle_geom)            
    def toggle_geom(self,event):
        geom=self.master.winfo_geometry()
        print(geom,self._geom)
        self.master.geometry(self._geom)
        self._geom=geom

root=tk.Tk()
app=FullScreenApp(root)
root.mainloop()

What certificates are trusted in truststore?

Is there any equivalent for the truststore? How can I view the trusted certificates?

Yes there is.The exact same command since keystore and truststore differ only in what they store i.e. private key or signed public key (certificate)

No other difference

How to handle configuration in Go

You might also be interested in go-libucl, a set of Go bindings for UCL, the Universal Configuration Language. UCL is a bit like JSON, but with better support for humans: it supports comments and human-readable constructs like SI multipliers (10k, 40M, etc.) and has a little bit less boilerplate (e.g., quotes around keys). It's actually pretty close to the nginx configuration file format, if you're already familiar with that.

Can you split/explode a field in a MySQL query?

Search in a column containing comma-separated values

MySQL has a dedicated function FIND_IN_SET() that returns field index if the value is found in a string containing comma-separated values.

For example, the following statement returns one-based index of value C in string A,B,C,D.

SELECT FIND_IN_SET('C', 'A,B,C,D') AS result;
+--------+
| result |
+--------+
|      3 |
+--------+

If the given value is not found, FIND_IN_SET() function returns 0.

SELECT FIND_IN_SET('Z', 'A,B,C,D') AS result;
+--------+
| result |
+--------+
|      0 |
+--------+

jquery multiple checkboxes array

This way will let you add or remove values when you check or uncheck any checkbox named as options[]:

var checkedValues = [];
$("input[name='options[]']").change(function() {
    const intValue = parseInt($(this).val());
    if ($(this).is(':checked')) {
        checkedValues.push(value);
    } else {
        const index = checkedValues.indexOf(value);
        if (index > -1) {
           checkedValues.splice(index, 1);
        }
    }
 });

How to call any method asynchronously in c#

Check out the MSDN article Asynchronous Programming with Async and Await if you can afford to play with new stuff. It was added to .NET 4.5.

Example code snippet from the link (which is itself from this MSDN sample code project):

// Three things to note in the signature: 
//  - The method has an async modifier.  
//  - The return type is Task or Task<T>. (See "Return Types" section.)
//    Here, it is Task<int> because the return statement returns an integer. 
//  - The method name ends in "Async."
async Task<int> AccessTheWebAsync()
{ 
    // You need to add a reference to System.Net.Http to declare client.
    HttpClient client = new HttpClient();

    // GetStringAsync returns a Task<string>. That means that when you await the 
    // task you'll get a string (urlContents).
    Task<string> getStringTask = client.GetStringAsync("http://msdn.microsoft.com");

    // You can do work here that doesn't rely on the string from GetStringAsync.
    DoIndependentWork();

    // The await operator suspends AccessTheWebAsync. 
    //  - AccessTheWebAsync can't continue until getStringTask is complete. 
    //  - Meanwhile, control returns to the caller of AccessTheWebAsync. 
    //  - Control resumes here when getStringTask is complete.  
    //  - The await operator then retrieves the string result from getStringTask. 
    string urlContents = await getStringTask;

    // The return statement specifies an integer result. 
    // Any methods that are awaiting AccessTheWebAsync retrieve the length value. 
    return urlContents.Length;
}

Quoting:

If AccessTheWebAsync doesn't have any work that it can do between calling GetStringAsync and awaiting its completion, you can simplify your code by calling and awaiting in the following single statement.

string urlContents = await client.GetStringAsync();

More details are in the link.

What are the best PHP input sanitizing functions?

function sanitize($string,$dbmin,$dbmax){
$string = preg_replace('#[^a-z0-9]#i', '', $string); //useful for strict cleanse, alphanumeric here
$string = mysqli_real_escape_string($con, $string); //get ready for db
if(strlen($string) > $dbmax || strlen($string) < $dbmin){
    echo "reject_this"; exit();
    }
return $string;
}

Retrieving the last record in each group - MySQL

The below query will work fine as per your question.

SELECT M1.* 
FROM MESSAGES M1,
(
 SELECT SUBSTR(Others_data,1,2),MAX(Others_data) AS Max_Others_data
 FROM MESSAGES
 GROUP BY 1
) M2
WHERE M1.Others_data = M2.Max_Others_data
ORDER BY Others_data;

Cannot add a project to a Tomcat server in Eclipse

Steps I used to resolve it:

  1. Double click on Tomcat Server in the Servers tab.
  2. In a dropdown next to Runtime Environment:, select Apache Tomcat your version
  3. Click on save.

Now, you should be able to add to server on right click "Add and Remove".

Note: Additionally, when on clear/run, you get an error for multiple instances, open server.xml and ensure that it contains a single instance of each application and not multiple.

adding and removing classes in angularJs using ng-click

you can also do that in a directive, if you want to remove the previous class and add a new class

    .directive('toggleClass', function() {
    return {
        restrict: 'A',
        link: function(scope, element, attrs) {
            element.bind('click', function() {
                if(element.attr("class") == "glyphicon glyphicon-pencil") {
                    element.removeClass("glyphicon glyphicon-pencil");
                    element.addClass(attrs.toggleClass);
                } else {
                    element.removeClass("glyphicon glyphicon-ok");
                    element.addClass("glyphicon glyphicon-pencil");
                }
            });
        }
    };
});

and in your template:

<i class="glyphicon glyphicon-pencil" toggle-class="glyphicon glyphicon-ok"></i>

nuget 'packages' element is not declared warning

This happens because VS doesn't know the schema of this file. Note that this file is more of an implementation detail, and not something you normally need to open directly. Instead, you can use the NuGet dialog to manage the packages installed in a project.

No converter found capable of converting from type to type

Turns out, when the table name is different than the model name, you have to change the annotations to:

@Entity
@Table(name = "table_name")
class WhateverNameYouWant {
    ...

Instead of simply using the @Entity annotation.

What was weird for me, is that the class it was trying to convert to didn't exist. This worked for me.

How to convert datetime to timestamp using C#/.NET (ignoring current timezone)

I'm not exactly sure what it is that you want. Do you want a TimeStamp? Then you can do something simple like:

TimeStamp ts = TimeStamp.FromTicks(value.ToUniversalTime().Ticks);

Since you named a variable epoch, do you want the Unix time equivalent of your date?

DateTime unixStart = DateTime.SpecifyKind(new DateTime(1970, 1, 1), DateTimeKind.Utc);
long epoch = (long)Math.Floor((value.ToUniversalTime() - unixStart).TotalSeconds);

jQuery callback on image load (even when the image is cached)

Just re-add the src argument on a separate line after the img oject is defined. This will trick IE into triggering the lad-event. It is ugly, but it is the simplest workaround I've found so far.

jQuery('<img/>', {
    src: url,
    id: 'whatever'
})
.load(function() {
})
.appendTo('#someelement');
$('#whatever').attr('src', url); // trigger .load on IE

How do I get the entity that represents the current user in Symfony2?

Well, first you need to request the username of the user from the session in your controller action like this:

$username=$this->get('security.context')->getToken()->getUser()->getUserName();

then do a query to the db and get your object with regular dql like

$em = $this->get('doctrine.orm.entity_manager');    
"SELECT u FROM Acme\AuctionBundle\Entity\User u where u.username=".$username;
$q=$em->createQuery($query);
$user=$q->getResult();

the $user should now hold the user with this username ( you could also use other fields of course)

...but you will have to first configure your /app/config/security.yml configuration to use the appropriate field for your security provider like so:

security:
 provider:
  example:
   entity: {class Acme\AuctionBundle\Entity\User, property: username}

hope this helps!

What is the reason for having '//' in Python?

// can be considered an alias to math.floor() for divisions with return value of type float. It operates as no-op for divisions with return value of type int.

import math
# let's examine `float` returns
# -------------------------------------
# divide
>>> 1.0 / 2
0.5
# divide and round down
>>> math.floor(1.0/2)
0.0
# divide and round down
>>> 1.0 // 2
0.0

# now let's examine `integer` returns
# -------------------------------------
>>> 1/2
0
>>> 1//2
0

Export HTML page to PDF on user click using JavaScript

This is because you define your "doc" variable outside of your click event. The first time you click the button the doc variable contains a new jsPDF object. But when you click for a second time, this variable can't be used in the same way anymore. As it is already defined and used the previous time.

change it to:

$(function () {

    var specialElementHandlers = {
        '#editor': function (element,renderer) {
            return true;
        }
    };
 $('#cmd').click(function () {
        var doc = new jsPDF();
        doc.fromHTML(
            $('#target').html(), 15, 15, 
            { 'width': 170, 'elementHandlers': specialElementHandlers }, 
            function(){ doc.save('sample-file.pdf'); }
        );

    });  
});

and it will work.

css background image in a different folder from css

For mac OS you should use this :

body {
 background: url(../../img/bg.png);
}

What does "Could not find or load main class" mean?

In my case, error appeared because I had supplied the source file name instead of the class name.

We need to supply the class name containing the main method to the interpreter.

How do I know if jQuery has an Ajax request pending?

$.active returns the number of active Ajax requests.

More info here

Using Mockito with multiple calls to the same method with the same arguments

You can do that using the thenAnswer method (when chaining with when):

when(someMock.someMethod()).thenAnswer(new Answer() {
    private int count = 0;

    public Object answer(InvocationOnMock invocation) {
        if (count++ == 1)
            return 1;

        return 2;
    }
});

Or using the equivalent, static doAnswer method:

doAnswer(new Answer() {
    private int count = 0;

    public Object answer(InvocationOnMock invocation) {
        if (count++ == 1)
            return 1;

        return 2;
    }
}).when(someMock).someMethod();

Why .NET String is immutable?

You never have to defensively copy immutable data. Despite the fact that you need to copy it to mutate it, often the ability to freely alias and never have to worry about unintended consequences of this aliasing can lead to better performance because of the lack of defensive copying.

How to clear APC cache entries?

apc_clear_cache() only works on the same php SAPI that you want you cache cleared. If you have PHP-FPM and want to clear apc cache, you have do do it through one of php scripts, NOT the command line, because the two caches are separated.

I have written CacheTool, a command line tool that solves exactly this problem and with one command you can clear your PHP-FPM APC cache from the commandline (it connects to php-fpm for you, and executes apc functions)

It also works for opcache.

See how it works here: http://gordalina.github.io/cachetool/

Find Active Tab using jQuery and Twitter Bootstrap

First of all you need to remove the data-toggle attribute. We will use some JQuery, so make sure you include it.

  <ul class='nav nav-tabs'>
    <li class='active'><a href='#home'>Home</a></li>
    <li><a href='#menu1'>Menu 1</a></li>
    <li><a href='#menu2'>Menu 2</a></li>
    <li><a href='#menu3'>Menu 3</a></li>
  </ul>

  <div class='tab-content'>
    <div id='home' class='tab-pane fade in active'>
      <h3>HOME</h3>
    <div id='menu1' class='tab-pane fade'>
      <h3>Menu 1</h3>
    </div>
    <div id='menu2' class='tab-pane fade'>
      <h3>Menu 2</h3>
    </div>
    <div id='menu3' class='tab-pane fade'>
      <h3>Menu 3</h3>
    </div>
  </div>
</div>

<script>
$(document).ready(function(){
// Handling data-toggle manually
    $('.nav-tabs a').click(function(){
        $(this).tab('show');
    });
// The on tab shown event
    $('.nav-tabs a').on('shown.bs.tab', function (e) {
        alert('Hello from the other siiiiiide!');
        var current_tab = e.target;
        var previous_tab = e.relatedTarget;
    });
});
</script>

Index (zero based) must be greater than or equal to zero

This can also happen when trying to throw an ArgumentException where you inadvertently call the ArgumentException constructor overload

public static void Dostuff(Foo bar)
{

   // this works
   throw new ArgumentException(String.Format("Could not find {0}", bar.SomeStringProperty));

   //this gives the error
   throw new ArgumentException(String.Format("Could not find {0}"), bar.SomeStringProperty);

}

Copy struct to struct in C

Your code is correct. You can also assign one directly to the other (see Joachim Pileborg's answer).

When you later come to compare the two structs, you need to be careful to compare the structs the long way, one member at a time, instead of using memcmp; see How do you compare structs for equality in C?

React Js: Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0

This error can be received but be aware it can be a red herring to the real issue. In my case, there wasn't an issue with the JSON as the error states, but rather a 404 was occurring that it could not pull the JSON data to process in the 1st place thus resulting in this error.

The fix for this was that in order to use fetch on a .json file in a local project, the .json file must be accessible. This can be done by placing it in a folder such as the public folder in the root of the project. Once I moved the json file into that folder, the 404 turned into a 200, and the Unexpected token < in JSON at position 0 error was resolved.

Convert timestamp to string

try this

SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
String string  = dateFormat.format(new Date());
System.out.println(string);

you can create any format see this

Integer to hex string in C++

To make it lighter and faster I suggest to use direct filling of a string.

template <typename I> std::string n2hexstr(I w, size_t hex_len = sizeof(I)<<1) {
    static const char* digits = "0123456789ABCDEF";
    std::string rc(hex_len,'0');
    for (size_t i=0, j=(hex_len-1)*4 ; i<hex_len; ++i,j-=4)
        rc[i] = digits[(w>>j) & 0x0f];
    return rc;
}

How to access random item in list?

I needed to more item instead of just one. So, I wrote this:

public static TList GetSelectedRandom<TList>(this TList list, int count)
       where TList : IList, new()
{
    var r = new Random();
    var rList = new TList();
    while (count > 0 && list.Count > 0)
    {
        var n = r.Next(0, list.Count);
        var e = list[n];
        rList.Add(e);
        list.RemoveAt(n);
        count--;
    }

    return rList;
}

With this, you can get elements how many you want as randomly like this:

var _allItems = new List<TModel>()
{
    // ...
    // ...
    // ...
}

var randomItemList = _allItems.GetSelectedRandom(10); 

How do you Make A Repeat-Until Loop in C++?

For an example if you want to have a loop that stopped when it has counted all of the people in a group. We will consider the value X to be equal to the number of the people in the group, and the counter will be used to count all of the people in the group. To write the

while(!condition)

the code will be:

int x = people;

int counter = 0;

while(x != counter)

{

counter++;

}

return 0;

How to host google web fonts on my own server?

You can actually download all font format variants directly from Google and include them in your css to serve from your server. That way you don't have to concern about Google tracking your site's users. However, the downside maybe slowing down your own serving speed. Fonts are quite demanding on resources. I have not done any tests in this issue yet, and wonder if anyone has similar thoughts.

How to copy a java.util.List into another java.util.List

subList function is a trick, the returned object is still in the original list. so if you do any operation in subList, it will cause the concurrent exception in your code, no matter it is single thread or multi thread.

ps command doesn't work in docker container

If you're running a CentOS container, you can install ps using this command:

yum install -y procps

Running this command on Dockerfile:

RUN yum install -y procps

SQLite select where empty?

There are several ways, like:

where some_column is null or some_column = ''

or

where ifnull(some_column, '') = ''

or

where coalesce(some_column, '') = ''

of

where ifnull(length(some_column), 0) = 0

How can I convert String to Int?

int i = Convert.ToInt32(TextBoxD1.Text);

Automatically get loop index in foreach loop in Perl

You shouldn't need to know the index in most circumstances. You can do this:

my @arr = (1, 2, 3);
foreach (@arr) {
    $_++;
}
print join(", ", @arr);

In this case, the output would be 2, 3, 4 as foreach sets an alias to the actual element, not just a copy.

How to get first 5 characters from string

An alternative way to get only one character.

$str = 'abcdefghij';
echo $str{5};

I would particularly not use this, but for the purpose of education. We can use that to answer the question:

$newString = '';
for ($i = 0; $i < 5; $i++) {
    $newString .= $str{$i};
}
echo $newString;

For anyone using that. Bear in mind curly brace syntax for accessing array elements and string offsets is deprecated from PHP 7.4

More information: https://wiki.php.net/rfc/deprecate_curly_braces_array_access

Selecting multiple items in ListView

In listView you can use it by Adapter

ArrayAdapter<String> adapterChannels = new ArrayAdapter<>(this, android.R.layout.simple_list_item_multiple_choice);

Creating a recursive method for Palindrome

Some of the codes are string heavy. Instead of creating substring which creates new object, we can just pass on indexes in recursive calls like below:

private static boolean isPalindrome(String str, int left, int right) {
    if(left >= right) {
        return true;
    }
    else {
        if(str.charAt(left) == str.charAt(right)) {

            return isPalindrome(str, ++left, --right);
        }
        else {
            return false;
        }
    }
}


 public static void main(String []args){
    String str = "abcdcbb"; 
    System.out.println(isPalindrome(str, 0, str.length()-1));
 }

Compare two MySQL databases

check: http://schemasync.org/ the schemasync tool works for me, it is a command line tool works easily in linux command line

How can I limit the visible options in an HTML <select> dropdown?

the size attribute matters, if the size=5 then first 5 items will be shown and for others you need to scroll down..

<select name="numbers" size="5">
    <option>1</option>
    <option>2</option>
    <option>3</option>
    <option>4</option>
    <option>5</option>
    <option>6</option>
    <option>7</option>
</select>

Is it possible to declare two variables of different types in a for loop?

No - but technically there is a work-around (not that i'd actually use it unless forced to):

for(struct { int a; char b; } s = { 0, 'a' } ; s.a < 5 ; ++s.a) 
{
    std::cout << s.a << " " << s.b << std::endl;
}

.gitignore and "The following untracked working tree files would be overwritten by checkout"

A simple solution might be: Just make sure that you are in the correct working directory in GitBash. That Message occure almost every time if a User tries to merge a directory too high in his folder hierarchy.

Example:

/workspace/git/myBashSourceFolder/myProjectSourcefolder

Scenario: User cloned repo in git-folder he created a new Java Project in Eclipse, imported the cloned repo. Eclipse set myProjectSourceFolder as Source Folder in his local Project. therefore the User entered it in git bash and pushed, pulled and commited his project from there. git syncs therefore myProjectSourceFolder - but has no record in his history for myBashSourceFolder. Therefore a push / pull /merge from myBashSourceFolder will produce the given output, if User tries to sync from there next time, instead of the folder he worked before.

Solution: Enter correct Folder and try a pull again. In almost every time I encountered, this solution worked fine :)

What is the easiest way to parse an INI File in C++?

this question is a bit old, but I will post my answer. I have tested various INI classes (you can see them on my website) and I also use simpleIni because I want to work with INI files on both windows and winCE. Window's GetPrivateProfileString() works only with the registry on winCE.

It is very easy to read with simpleIni. Here is an example:

#include "SimpleIni\SimpleIni.h"    
CSimpleIniA ini;
ini.SetUnicode();
ini.LoadFile(FileName);
const char * pVal = ini.GetValue(section, entry, DefaultStr);

File size exceeds configured limit (2560000), code insight features not available

For those who don't know where to find the file they're talking about. On my machine (OSX) it is in:

  • PyCharm CE: /Applications/PyCharm CE.app/Contents/bin/idea.properties
  • WebStorm: /Applications/WebStorm.app/Contents/bin/idea.properties

Java and HTTPS url connection without downloading certificate

Use the latest X509ExtendedTrustManager instead of X509Certificate as advised here: java.security.cert.CertificateException: Certificates does not conform to algorithm constraints

    package javaapplication8;

    import java.io.InputStream;
    import java.net.Socket;
    import java.net.URL;
    import java.net.URLConnection;
    import java.security.cert.CertificateException;
    import java.security.cert.X509Certificate;
    import javax.net.ssl.HostnameVerifier;
    import javax.net.ssl.HttpsURLConnection;
    import javax.net.ssl.SSLContext;
    import javax.net.ssl.SSLEngine;
    import javax.net.ssl.SSLSession;
    import javax.net.ssl.TrustManager;
    import javax.net.ssl.X509ExtendedTrustManager;

    /**
     *
     * @author hoshantm
     */
    public class JavaApplication8 {

        /**
         * @param args the command line arguments
         * @throws java.lang.Exception
         */
        public static void main(String[] args) throws Exception {
            /*
             *  fix for
             *    Exception in thread "main" javax.net.ssl.SSLHandshakeException:
             *       sun.security.validator.ValidatorException:
             *           PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException:
             *               unable to find valid certification path to requested target
             */
            TrustManager[] trustAllCerts = new TrustManager[]{
                new X509ExtendedTrustManager() {
                    @Override
                    public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                        return null;
                    }

                    @Override
                    public void checkClientTrusted(X509Certificate[] certs, String authType) {
                    }

                    @Override
                    public void checkServerTrusted(X509Certificate[] certs, String authType) {
                    }

                    @Override
                    public void checkClientTrusted(X509Certificate[] xcs, String string, Socket socket) throws CertificateException {

                    }

                    @Override
                    public void checkServerTrusted(X509Certificate[] xcs, String string, Socket socket) throws CertificateException {

                    }

                    @Override
                    public void checkClientTrusted(X509Certificate[] xcs, String string, SSLEngine ssle) throws CertificateException {

                    }

                    @Override
                    public void checkServerTrusted(X509Certificate[] xcs, String string, SSLEngine ssle) throws CertificateException {

                    }

                }
            };

            SSLContext sc = SSLContext.getInstance("SSL");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());

            // Create all-trusting host name verifier
            HostnameVerifier allHostsValid = new HostnameVerifier() {
                @Override
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            };
            // Install the all-trusting host verifier
            HttpsURLConnection.setDefaultHostnameVerifier(allHostsValid);
            /*
             * end of the fix
             */

            URL url = new URL("https://10.52.182.224/cgi-bin/dynamic/config/panel.bmp");
            URLConnection con = url.openConnection();
            //Reader reader = new ImageStreamReader(con.getInputStream());

            InputStream is = new URL(url.toString()).openStream();

            // Whatever you may want to do next

        }

    }

How to subtract hours from a date in Oracle so it affects the day also

Try this:

SELECT to_char(sysdate - (2 / 24), 'MM-DD-YYYY HH24') FROM DUAL

To test it using a new date instance:

SELECT to_char(TO_DATE('11/06/2015 00:00','dd/mm/yyyy HH24:MI') - (2 / 24), 'MM-DD-YYYY HH24:MI') FROM DUAL

Output is: 06-10-2015 22:00, which is the previous day.

Displaying all table names in php from MySQL database

For people that are using PDO statements

$query = $db->prepare('show tables');
$query->execute();

while($rows = $query->fetch(PDO::FETCH_ASSOC)){
     var_dump($rows);
}

How to pass arguments to a Button command in Tkinter?

The best thing to do is use lambda as follows:

button = Tk.Button(master=frame, text='press', command=lambda: action(someNumber))

How to check that Request.QueryString has a specific value or not in ASP.NET?

What about a more direct approach?

if (Request.QueryString.AllKeys.Contains("mykey")

How to use the CSV MIME-type?

You could try to force the browser to open a "Save As..." dialog by doing something like:

header('Content-type: text/csv');
header('Content-disposition: attachment;filename=MyVerySpecial.csv');
echo "cell 1, cell 2";

Which should work across most major browsers.

"Least Astonishment" and the Mutable Default Argument

5 points in defense of Python

  1. Simplicity: The behavior is simple in the following sense: Most people fall into this trap only once, not several times.

  2. Consistency: Python always passes objects, not names. The default parameter is, obviously, part of the function heading (not the function body). It therefore ought to be evaluated at module load time (and only at module load time, unless nested), not at function call time.

  3. Usefulness: As Frederik Lundh points out in his explanation of "Default Parameter Values in Python", the current behavior can be quite useful for advanced programming. (Use sparingly.)

  4. Sufficient documentation: In the most basic Python documentation, the tutorial, the issue is loudly announced as an "Important warning" in the first subsection of Section "More on Defining Functions". The warning even uses boldface, which is rarely applied outside of headings. RTFM: Read the fine manual.

  5. Meta-learning: Falling into the trap is actually a very helpful moment (at least if you are a reflective learner), because you will subsequently better understand the point "Consistency" above and that will teach you a great deal about Python.

Difference between if () { } and if () : endif;

Both are the same.

But: If you want to use PHP as your templating language in your view files(the V of MVC) you can use this alternate syntax to distinguish between php code written to implement business-logic (Controller and Model parts of MVC) and gui-logic. Of course it is not mandatory and you can use what ever syntax you like.

ZF uses that approach.

Warning: mysqli_query() expects at least 2 parameters, 1 given. What?

the mysqli_queryexcepts 2 parameters , first variable is mysqli_connectequivalent variable , second one is the query you have provided

$name1 = mysqli_connect(localhost,tdoylex1_dork,dorkk,tdoylex1_dork);

$name2 = mysqli_query($name1,"SELECT name FROM users ORDER BY RAND() LIMIT 1");

AES Encrypt and Decrypt

I found the solution, it is a good library.

Cross platform 256bit AES encryption / decryption.

This project contains the implementation of 256 bit AES encryption which works on all the platforms (C#, iOS, Android). One of the key objective is to make AES work on all the platforms with simple implementation.

Platforms Supported: iOS , Android , Windows (C#).

https://github.com/Pakhee/Cross-platform-AES-encryption

Best way to stress test a website

Maybe grinder will help? You can simulate concurrent request by threads and lightweight processes or distribute test over several machines. I'm using it extensively with success every time.

Using FFmpeg in .net?

You can use this nuget package:

Install-Package Xabe.FFmpeg

I'm trying to make easy to use, cross-platform FFmpeg wrapper.

You can find more information about this at Xabe.FFmpeg

More info in documentation

Conversion is simple:

IConversionResult result = await Conversion.ToMp4(Resources.MkvWithAudio, output).Start();

How can I pass a parameter to a t-sql script?

Two options save vijay.sql

declare
begin
execute immediate 
'CREATE TABLE DMS_POP_WKLY_REFRESH_'||to_char(sysdate,'YYYYMMDD')||' NOLOGGING PARALLEL AS
SELECT wk.*,bbc.distance_km ,NVL(bbc.tactical_broadband_offer,0) tactical_broadband_offer ,
       sel.tactical_select_executive_flag,
       sel.agent_name,
       res.DMS_RESIGN_CAMPAIGN_CODE,
       pclub.tactical_select_flag
FROM   spineowner.pop_wkly_refresh_20100201 wk,
       dms_bb_coverage_102009 bbc,
       dms_select_executive_group sel,
       DMS_RESIGN_CAMPAIGN_26052009 res,
       DMS_PRIORITY_CLUB pclub
WHERE  wk.mpn = bbc.mpn(+)
AND    wk.mpn = sel.mpn (+)
AND    wk.mpn = res.mpn (+)
AND    wk.mpn = pclub.mpn (+)'
end;
/

The above will generate table names automatically based on sysdate. If you still need to pass as variable, then save vijay.sql as

declare
begin
execute immediate 
'CREATE TABLE DMS_POP_WKLY_REFRESH_'||&1||' NOLOGGING PARALLEL AS
SELECT wk.*,bbc.distance_km ,NVL(bbc.tactical_broadband_offer,0) tactical_broadband_offer ,
       sel.tactical_select_executive_flag,
       sel.agent_name,
       res.DMS_RESIGN_CAMPAIGN_CODE,
       pclub.tactical_select_flag
FROM   spineowner.pop_wkly_refresh_20100201 wk,
       dms_bb_coverage_102009 bbc,
       dms_select_executive_group sel,
       DMS_RESIGN_CAMPAIGN_26052009 res,
       DMS_PRIORITY_CLUB pclub
WHERE  wk.mpn = bbc.mpn(+)
AND    wk.mpn = sel.mpn (+)
AND    wk.mpn = res.mpn (+)
AND    wk.mpn = pclub.mpn (+)'
end;
/

and then run as sqlplus -s username/password @vijay.sql '20100101'

Print page numbers on pages when printing html

   **@page {
            margin-top:21% !important; 
            @top-left{
            content: element(header);

            }

            @bottom-left {
            content: element(footer
 }
 div.header {

            position: running(header);

            }
            div.footer {

            position: running(footer);
            border-bottom: 2px solid black;


            }
           .pagenumber:before {
            content: counter(page);
            }
            .pagecount:before {
            content: counter(pages);
            }      
 <div class="footer" style="font-size:12pt; font-family: Arial; font-family: Arial;">
                <span>Page <span class="pagenumber"/> of <span class="pagecount"/></span>
            </div >**

How to quickly form groups (quartiles, deciles, etc) by ordering column(s) in a data frame

Try this function

getQuantileGroupNum <- function(vec, group_num, decreasing=FALSE) {
  if(decreasing) {
    abs(cut(vec, quantile(vec, probs=seq(0, 1, 1 / group_num), type=8, na.rm=TRUE), labels=FALSE, include.lowest=T) - group_num - 1)
  } else {
    cut(vec, quantile(vec, probs=seq(0, 1, 1 / group_num), type=8, na.rm=TRUE), labels=FALSE, include.lowest=T)
  }
}
> t1 <- runif(7)
> t1
[1] 0.4336094 0.2842928 0.5578876 0.2678694 0.6495285 0.3706474 0.5976223
> getQuantileGroupNum(t1, 4)
[1] 2 1 3 1 4 2 4
> getQuantileGroupNum(t1, 4, decreasing=T)
[1] 3 4 2 4 1 3 1

Fatal error: Maximum execution time of 30 seconds exceeded in C:\xampp\htdocs\wordpress\wp-includes\class-http.php on line 1610

  1. Find file:

    [XAMPP Installation Directory]\php\php.ini
    
  2. open php.ini.
  3. Find max_execution_time and increase the value of it as you required
  4. Restart XAMPP control panel

SQLAlchemy default DateTime

Calculate timestamps within your DB, not your client

For sanity, you probably want to have all datetimes calculated by your DB server, rather than the application server. Calculating the timestamp in the application can lead to problems because network latency is variable, clients experience slightly different clock drift, and different programming languages occasionally calculate time slightly differently.

SQLAlchemy allows you to do this by passing func.now() or func.current_timestamp() (they are aliases of each other) which tells the DB to calculate the timestamp itself.

Use SQLALchemy's server_default

Additionally, for a default where you're already telling the DB to calculate the value, it's generally better to use server_default instead of default. This tells SQLAlchemy to pass the default value as part of the CREATE TABLE statement.

For example, if you write an ad hoc script against this table, using server_default means you won't need to worry about manually adding a timestamp call to your script--the database will set it automatically.

Understanding SQLAlchemy's onupdate/server_onupdate

SQLAlchemy also supports onupdate so that anytime the row is updated it inserts a new timestamp. Again, best to tell the DB to calculate the timestamp itself:

from sqlalchemy.sql import func

time_created = Column(DateTime(timezone=True), server_default=func.now())
time_updated = Column(DateTime(timezone=True), onupdate=func.now())

There is a server_onupdate parameter, but unlike server_default, it doesn't actually set anything serverside. It just tells SQLalchemy that your database will change the column when an update happens (perhaps you created a trigger on the column ), so SQLAlchemy will ask for the return value so it can update the corresponding object.

One other potential gotcha:

You might be surprised to notice that if you make a bunch of changes within a single transaction, they all have the same timestamp. That's because the SQL standard specifies that CURRENT_TIMESTAMP returns values based on the start of the transaction.

PostgreSQL provides the non-SQL-standard statement_timestamp() and clock_timestamp() which do change within a transaction. Docs here: https://www.postgresql.org/docs/current/static/functions-datetime.html#FUNCTIONS-DATETIME-CURRENT

UTC timestamp

If you want to use UTC timestamps, a stub of implementation for func.utcnow() is provided in SQLAlchemy documentation. You need to provide appropriate driver-specific functions on your own though.

git: Switch branch and ignore any changes without committing

You need a clean state to change branches. The branch checkout will only be allowed if it does not affect the 'dirty files' (as Charles Bailey remarks in the comments).

Otherwise, you should either:

  • stash your current change or
  • reset --hard HEAD (if you do not mind losing those minor changes) or
  • checkout -f (When switching branches, proceed even if the index or the working tree differs from HEAD. This is used to throw away local changes. )

Or, more recently:

Proceed even if the index or the working tree differs from HEAD.
Both the index and working tree are restored to match the switching target.

This differs from git switch -m <branch-name>, which triggers a three-way merge between the current branch, your working tree contents, and the new branch is done: you won't loose your work in progress that way.

Unzipping files

I'm using zip.js and it seems to be quite useful. It's worth a look!

Check the Unzip demo, for example.

apc vs eaccelerator vs xcache

Check out benchmarks and comparisons:

here and here and there

Field 'browser' doesn't contain a valid alias configuration

In my situation, I did not have an export at the bottom of my webpack.config.js file. Simply adding

export default Config;

solved it.

JQuery Ajax Post results in 500 Internal Server Error

Your return string data can be very long.

<system.web>        
   <compilation debug="true" targetFramework="4.0" />
   <httpRuntime maxRequestLength="2147483647" />
</system.web>

For example:

  • 1 Char = 1 Byte
  • 5 Char = 5 Byte
  • "Hakki" = 5 Byte

How to get Current Directory?

#include <iostream>    
#include <stdio.h>
#include <dirent.h>

std::string current_working_directory()
{
    char* cwd = _getcwd( 0, 0 ) ; // **** microsoft specific ****
    std::string working_directory(cwd) ;
    std::free(cwd) ;
    return working_directory ;
}

int main(){
    std::cout << "i am now in " << current_working_directory() << endl;
}

I failed to use GetModuleFileName correctly. I found this work very well. just tested on Windows, not yet try on Linux :)

How to measure elapsed time in Python?

The timeit module is good for timing a small piece of Python code. It can be used at least in three forms:

1- As a command-line module

python2 -m timeit 'for i in xrange(10): oct(i)' 

2- For a short code, pass it as arguments.

import timeit
timeit.Timer('for i in xrange(10): oct(i)').timeit()

3- For longer code as:

import timeit
code_to_test = """
a = range(100000)
b = []
for i in a:
    b.append(i*2)
"""
elapsed_time = timeit.timeit(code_to_test, number=100)/100
print(elapsed_time)

Eclipse "Server Locations" section disabled and need to change to use Tomcat installation

Right click on the server, then Add/Remove, then remove any projects that are in the Configured panel. Then right click on the server and choose "Clean..." from the context menu. Then the Server Locations option will be enabled.

How to display all methods of an object?

It's not possible with ES3 as the properties have an internal DontEnum attribute which prevents us from enumerating these properties. ES5, on the other hand, provides property descriptors for controlling the enumeration capabilities of properties so user-defined and native properties can use the same interface and enjoy the same capabilities, which includes being able to see non-enumerable properties programmatically.

The getOwnPropertyNames function can be used to enumerate over all properties of the passed in object, including those that are non-enumerable. Then a simple typeof check can be employed to filter out non-functions. Unfortunately, Chrome is the only browser that it works on currently.

?function getAllMethods(object) {
    return Object.getOwnPropertyNames(object).filter(function(property) {
        return typeof object[property] == 'function';
    });
}

console.log(getAllMethods(Math));

logs ["cos", "pow", "log", "tan", "sqrt", "ceil", "asin", "abs", "max", "exp", "atan2", "random", "round", "floor", "acos", "atan", "min", "sin"] in no particular order.

Creating new database from a backup of another Database on the same server?

It's even possible to restore without creating a blank database at all.

In Sql Server Management Studio, right click on Databases and select Restore Database... enter image description here

In the Restore Database dialog, select the Source Database or Device as normal. Once the source database is selected, SSMS will populate the destination database name based on the original name of the database.

It's then possible to change the name of the database and enter a new destination database name.

enter image description here

With this approach, you don't even need to go to the Options tab and click the "Overwrite the existing database" option.

Also, the database files will be named consistently with your new database name and you still have the option to change file names if you want.

How to extract file name from path?

The simplest approach if you are sure the file physically exists on the disk:

Dim fileName, filePath As String
filePath = "C:\Documents\myfile.pdf"
fileName = Dir(filePath)

If you are not sure about existence of file or just want to extract filename from a given path then, simplest approach is:

fileName = Mid(filePath, InStrRev(filePath, "\") + 1)

Checking whether the pip is installed?

pip list is a shell command. You should run it in your shell (bash/cmd), rather than invoke it from python interpreter.

pip does not provide a stable API. The only supported way of calling it is via subprocess, see docs and the code at the end of this answer.

However, if you want to just check if pip exists locally, without running it, and you are running Linux, I would suggest that you use bash's which command:

which pip

It should show you whether the command can be found in bash's PATH/aliases, and if it does, what does it actually execute.

If running pip is not an issue, you could just do:

python -m pip --version

If you really need to do it from a python script, you can always put the import statement into a try...except block:

try:
    import pip
except ImportError:
    print("Pip not present.")

Or check what's the output of a pip --version using subprocess module:

subprocess.check_call([sys.executable, '-m', 'pip', '--version'])

How to convert data.frame column from Factor to numeric

As an alternative to $dollarsign notation, use a within block:

breast <- within(breast, {
  class <- as.numeric(as.character(class))
})

Note that you want to convert your vector to a character before converting it to a numeric. Simply calling as.numeric(class) will not the ids corresponding to each factor level (1, 2) rather than the levels themselves.

What is the difference between Step Into and Step Over in a debugger

step into will dig into method calls
step over will just execute the line and go to the next one