Programs & Examples On #Assert

An assertion is a statement, which aborts a program when it evaluates to false. Assert is typically used for debugging and situations which should never happen.

How to check if an object is a list or tuple (but not string)?

In python 2 only (not python 3):

assert not isinstance(lst, basestring)

Is actually what you want, otherwise you'll miss out on a lot of things which act like lists, but aren't subclasses of list or tuple.

How to handle AssertionError in Python and find out which line or statement it occurred on?

The traceback module and sys.exc_info are overkill for tracking down the source of an exception. That's all in the default traceback. So instead of calling exit(1) just re-raise:

try:
    assert "birthday cake" == "ice cream cake", "Should've asked for pie"
except AssertionError:
    print 'Houston, we have a problem.'
    raise

Which gives the following output that includes the offending statement and line number:

Houston, we have a problem.
Traceback (most recent call last):
  File "/tmp/poop.py", line 2, in <module>
    assert "birthday cake" == "ice cream cake", "Should've asked for pie"
AssertionError: Should've asked for pie

Similarly the logging module makes it easy to log a traceback for any exception (including those which are caught and never re-raised):

import logging

try:
    assert False == True 
except AssertionError:
    logging.error("Nothing is real but I can't quit...", exc_info=True)

How do I use Assert to verify that an exception has been thrown?

Check out nUnit Docs for examples about:

[ExpectedException( typeof( ArgumentException ) )]

How can I check if some text exist or not in the page using Selenium?

With XPath, it's not that hard. Simply search for all elements containing the given text:

List<WebElement> list = driver.findElements(By.xpath("//*[contains(text(),'" + text + "')]"));
Assert.assertTrue("Text not found!", list.size() > 0);

The official documentation is not very supportive with tasks like this, but it is the basic tool nonetheless.

The JavaDocs are greater, but it takes some time to get through everything useful and unuseful.

To learn XPath, just follow the internet. The spec is also a surprisingly good read.


EDIT:

Or, if you don't want your Implicit Wait to make the above code wait for the text to appear, you can do something in the way of this:

String bodyText = driver.findElement(By.tagName("body")).getText();
Assert.assertTrue("Text not found!", bodyText.contains(text));

How to automatically generate a stacktrace when my program crashes

ulimit -c unlimited

is a system variable, wich will allow to create a core dump after your application crashes. In this case an unlimited amount. Look for a file called core in the very same directory. Make sure you compiled your code with debugging informations enabled!

regards

PHPUnit assert that an exception was thrown?

An alternative way can be the following:

$this->expectException(\InvalidArgumentException::class);
$this->expectExceptionMessage('Expected Exception Message');

Please ensure that your test class extents \PHPUnit_Framework_TestCase.

What does the "assert" keyword do?

assert is a debugging tool that will cause the program to throw an AssertionFailed exception if the condition is not true. In this case, the program will throw an exception if either of the two conditions following it evaluate to false. Generally speaking, assert should not be used in production code

Why doesn't JUnit provide assertNotEquals methods?

I agree totally with the OP point of view. Assert.assertFalse(expected.equals(actual)) is not a natural way to express an inequality.
But I would argue that further than Assert.assertEquals(), Assert.assertNotEquals() works but is not user friendly to document what the test actually asserts and to understand/debug as the assertion fails.
So yes JUnit 4.11 and JUnit 5 provides Assert.assertNotEquals() (Assertions.assertNotEquals() in JUnit 5) but I really avoid using them.

As alternative, to assert the state of an object I general use a matcher API that digs into the object state easily, that document clearly the intention of the assertions and that is very user friendly to understand the cause of the assertion failure.

Here is an example.
Suppose I have an Animal class which I want to test the createWithNewNameAndAge() method, a method that creates a new Animal object by changing its name and its age but by keeping its favorite food.
Suppose I use Assert.assertNotEquals() to assert that the original and the new objects are different.
Here is the Animal class with a flawed implementation of createWithNewNameAndAge() :

public class Animal {

    private String name;
    private int age;
    private String favoriteFood;

    public Animal(String name, int age, String favoriteFood) {
        this.name = name;
        this.age = age;
        this.favoriteFood = favoriteFood;
    }

    // Flawed implementation : use this.name and this.age to create the 
    // new Animal instead of using the name and age parameters
    public Animal createWithNewNameAndAge(String name, int age) {
        return new Animal(this.name, this.age, this.favoriteFood);
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getFavoriteFood() {
        return favoriteFood;
    }

    @Override
    public String toString() {
        return "Animal [name=" + name + ", age=" + age + ", favoriteFood=" + favoriteFood + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + ((favoriteFood == null) ? 0 : favoriteFood.hashCode());
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Animal)) return false;

        Animal other = (Animal) obj;
        return age == other.age && favoriteFood.equals(other.favoriteFood) &&
                name.equals(other.name);
    }

}

JUnit 4.11+ (or JUnit 5) both as test runner and assertion tool

@Test
void assertListNotEquals_JUnit_way() {
    Animal scoubi = new Animal("scoubi", 10, "hay");
    Animal littleScoubi = scoubi.createWithNewNameAndAge("little scoubi", 1);
    Assert.assertNotEquals(scoubi, littleScoubi);
}

The test fails as expected but the cause provided to the developer is really not helpful. It just says that the values should be different and output the toString() result invoked on the actual Animal parameter :

java.lang.AssertionError: Values should be different. Actual: Animal

[name=scoubi, age=10, favoriteFood=hay]

at org.junit.Assert.fail(Assert.java:88)

Ok the objects are not equals. But where is the problem ?
Which field is not correctly valued in the tested method ? One ? Two ? All of them ?
To discover it you have to dig in the createWithNewNameAndAge() implementation/use a debugger while the testing API would be much more friendly if it would make for us the differential between which is expected and which is gotten.


JUnit 4.11 as test runner and a test Matcher API as assertion tool

Here the same scenario of test but that uses AssertJ (an excellent test matcher API) to make the assertion of the Animal state: :

import org.assertj.core.api.Assertions;

@Test
void assertListNotEquals_AssertJ() {
    Animal scoubi = new Animal("scoubi", 10, "hay");
    Animal littleScoubi = scoubi.createWithNewNameAndAge("little scoubi", 1);
    Assertions.assertThat(littleScoubi)
              .extracting(Animal::getName, Animal::getAge, Animal::getFavoriteFood)
              .containsExactly("little scoubi", 1, "hay");
}

Of course the test still fails but this time the reason is clearly stated :

java.lang.AssertionError:

Expecting:

<["scoubi", 10, "hay"]>

to contain exactly (and in same order):

<["little scoubi", 1, "hay"]>

but some elements were not found:

<["little scoubi", 1]>

and others were not expected:

<["scoubi", 10]>

at junit5.MyTest.assertListNotEquals_AssertJ(MyTest.java:26)

We can read that for Animal::getName, Animal::getAge, Animal::getFavoriteFood values of the returned Animal, we expect to have these value :

"little scoubi", 1, "hay" 

but we have had these values :

"scoubi", 10, "hay"

So we know where investigate : name and age are not correctly valued. Additionally, the fact of specifying the hay value in the assertion of Animal::getFavoriteFood() allows also to more finely assert the returned Animal. We want that the objects be not the same for some properties but not necessarily for every properties.
So definitely, using a matcher API is much more clear and flexible.

What is “assert” in JavaScript?

If using a modern browser or nodejs, you can use console.assert(expression, object).

For more information:

How do you assert that a certain exception is thrown in JUnit 4 tests?

I tried many of the methods here, but they were either complicated or didn't quite meet my requirements. In fact, one can write a helper method quite simply:

public class ExceptionAssertions {
    public static void assertException(BlastContainer blastContainer ) {
        boolean caughtException = false;
        try {
            blastContainer.test();
        } catch( Exception e ) {
            caughtException = true;
        }
        if( !caughtException ) {
            throw new AssertionFailedError("exception expected to be thrown, but was not");
        }
    }
    public static interface BlastContainer {
        public void test() throws Exception;
    }
}

Use it like this:

assertException(new BlastContainer() {
    @Override
    public void test() throws Exception {
        doSomethingThatShouldExceptHere();
    }
});

Zero dependencies: no need for mockito, no need powermock; and works just fine with final classes.

Java/ JUnit - AssertTrue vs AssertFalse

The point is semantics. In assertTrue, you are asserting that the expression is true. If it is not, then it will display the message and the assertion will fail. In assertFalse, you are asserting that an expression evaluates to false. If it is not, then the message is displayed and the assertion fails.

assertTrue (message, value == false) == assertFalse (message, value);

These are functionally the same, but if you are expecting a value to be false then use assertFalse. If you are expecting a value to be true, then use assertTrue.

What is the use of "assert"?

The assert statement has two forms.

The simple form, assert <expression>, is equivalent to

if __?debug__:
    if not <expression>: raise AssertionError

The extended form, assert <expression1>, <expression2>, is equivalent to

if __?debug__:
    if not <expression1>: raise AssertionError, <expression2>

Proper way to assert type of variable in Python

Doing type('') is effectively equivalent to str and types.StringType

so type('') == str == types.StringType will evaluate to "True"

Note that Unicode strings which only contain ASCII will fail if checking types in this way, so you may want to do something like assert type(s) in (str, unicode) or assert isinstance(obj, basestring), the latter of which was suggested in the comments by 007Brendan and is probably preferred.

isinstance() is useful if you want to ask whether an object is an instance of a class, e.g:

class MyClass: pass

print isinstance(MyClass(), MyClass) # -> True
print isinstance(MyClass, MyClass()) # -> TypeError exception

But for basic types, e.g. str, unicode, int, float, long etc asking type(var) == TYPE will work OK.

Best practice for using assert?

To be able to automatically throw an error when x become less than zero throughout the function. You can use class descriptors. Here is an example:

class LessThanZeroException(Exception):
    pass

class variable(object):
    def __init__(self, value=0):
        self.__x = value

    def __set__(self, obj, value):
        if value < 0:
            raise LessThanZeroException('x is less than zero')

        self.__x  = value

    def __get__(self, obj, objType):
        return self.__x

class MyClass(object):
    x = variable()

>>> m = MyClass()
>>> m.x = 10
>>> m.x -= 20
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "my.py", line 7, in __set__
    raise LessThanZeroException('x is less than zero')
LessThanZeroException: x is less than zero

How to do a JUnit assert on a message in a logger

Thanks a lot for these (surprisingly) quick and helpful answers; they put me on the right way for my solution.

The codebase were I want to use this, uses java.util.logging as its logger mechanism, and I don't feel at home enough in those codes to completely change that to log4j or to logger interfaces/facades. But based on these suggestions, I 'hacked-up' a j.u.l.handler extension and that works as a treat.

A short summary follows. Extend java.util.logging.Handler:

class LogHandler extends Handler
{
    Level lastLevel = Level.FINEST;

    public Level  checkLevel() {
        return lastLevel;
    }    

    public void publish(LogRecord record) {
        lastLevel = record.getLevel();
    }

    public void close(){}
    public void flush(){}
}

Obviously, you can store as much as you like/want/need from the LogRecord, or push them all into a stack until you get an overflow.

In the preparation for the junit-test, you create a java.util.logging.Logger and add such a new LogHandler to it:

@Test tester() {
    Logger logger = Logger.getLogger("my junit-test logger");
    LogHandler handler = new LogHandler();
    handler.setLevel(Level.ALL);
    logger.setUseParentHandlers(false);
    logger.addHandler(handler);
    logger.setLevel(Level.ALL);

The call to setUseParentHandlers() is to silence the normal handlers, so that (for this junit-test run) no unnecessary logging happens. Do whatever your code-under-test needs to use this logger, run the test and assertEquality:

    libraryUnderTest.setLogger(logger);
    methodUnderTest(true);  // see original question.
    assertEquals("Log level as expected?", Level.INFO, handler.checkLevel() );
}

(Of course, you would move large part of this work into a @Before method and make assorted other improvements, but that would clutter this presentation.)

AssertContains on strings in jUnit

Use hamcrest Matcher containsString()

// Hamcrest assertion
assertThat(person.getName(), containsString("myName"));

// Error Message
java.lang.AssertionError:
Expected: a string containing "myName"
     got: "some other name"

You can optional add an even more detail error message.

// Hamcrest assertion with custom error message
assertThat("my error message", person.getName(), containsString("myName"));

// Error Message
java.lang.AssertionError: my error message
Expected: a string containing "myName"
     got: "some other name"

Posted my answer to a duplicate question here

C# - What does the Assert() method do? Is it still useful?

From Code Complete

8 Defensive Programming

8.2 Assertions

An assertion is code that’s used during development—usually a routine or macro—that allows a program to check itself as it runs. When a assertion is true, that means everything is operating as expected. When it’s false, that means it has detected an unexpected error in the code. For example, if the system assumes that a customer-information file will never have more than 50,000 records, the program might contain an assertion that the number of records is less than or equal to 50,000. As long as the number of records is less than or equal to 50,000, the assertion will be silent. If it encounters more than 50,000 records, however, it will loudly “assert” that there is a error in the program.

Assertions are especially useful in large, complicated programs and in high-reliability programs. They enable programmers to more quickly flush out mismatched interface assumptions, errors that creep in when the code is modified, and so on.

An assertion usually takes two arguments: a boolean expression that describes the assumption that’s supposed to be true and a message to display if it isn’t.

(…)

Normally, you don’t want users to see assertion messages in production code; assertions are primarily for use during development and maintenance. Assertions are normally compiled into the code at development time and compiled out of the code for production. During development, assertions flush out contradictory assumptions, unexpected conditions, bad values passed to routines, and so on. During production, they are compiled out of the code so that the assertions don’t degrade system performance.

How do I check (at runtime) if one class is a subclass of another?

issubclass(class, classinfo)

Excerpt:

Return true if class is a subclass (direct, indirect or virtual) of classinfo.

What is the "assert" function?

Stuff like 'raises exception' and 'halts execution' might be true for most compilers, but not for all. (BTW, are there assert statements that really throw exceptions?)

Here's an interesting, slightly different meaning of assert used by c6x and other TI compilers: upon seeing certain assert statements, these compilers use the information in that statement to perform certain optimizations. Wicked.

Example in C:

int dot_product(short *x, short *y, short z)
{
  int sum = 0
  int i;

  assert( ( (int)(x) & 0x3 ) == 0 );
  assert( ( (int)(y) & 0x3 ) == 0 );

  for( i = 0 ; i < z ; ++i )
    sum += x[ i ] * y[ i ];
  return sum;
}

This tells de compiler the arrays are aligned on 32-bits boundaries, so the compiler can generate specific instructions made for that kind of alignment.

How to change css property using javascript

This is really easy using jQuery.

For instance:

$(".left").mouseover(function(){$(".left1").show()});
$(".left").mouseout(function(){$(".left1").hide()});

I've update your fiddle: http://jsfiddle.net/TqDe9/2/

Java constructor/method with optional parameters?

You can use varargs for optional parameters:

public class Booyah {
    public static void main(String[] args) {
        woohoo(1);
        woohoo(2, 3);
    }
    static void woohoo(int required, Integer... optional) {
        Integer lala;
        if (optional.length == 1) {
            lala = optional[0];
        } else {
            lala = 2;
        }
        System.out.println(required + lala);
    }
}

Also it's important to note the use of Integer over int. Integer is a wrapper around the primitive int, which allows one to make comparisons with null as necessary.

Static class initializer in PHP

NOTE: This is exactly what OP said they did. (But didn't show code for.) I show the details here, so that you can compare it to the accepted answer. My point is that OP's original instinct was, IMHO, better than the answer he accepted.


Given how highly upvoted the accepted answer is, I'd like to point out the "naive" answer to one-time initialization of static methods, is hardly more code than that implementation of Singleton -- and has an essential advantage.

final class MyClass  {
    public static function someMethod1() {
        MyClass::init();
        // whatever
    }

    public static function someMethod2() {
        MyClass::init();
        // whatever
    }


    private static $didInit = false;

    private static function init() {
        if (!self::$didInit) {
            self::$didInit = true;
            // one-time init code.
        }
    }

    // private, so can't create an instance.
    private function __construct() {
        // Nothing to do - there are no instances.
    }
}

The advantage of this approach, is that you get to call with the straightforward static function syntax:

MyClass::someMethod1();

Contrast it to the calls required by the accepted answer:

MyClass::getInstance->someMethod1();

As a general principle, it is best to pay the coding price once, when you code a class, to keep callers simpler.


If you are NOT using PHP 7.4's opcode.cache, then use Victor Nicollet's answer. Simple. No extra coding required. No "advanced" coding to understand. (I recommend including FrancescoMM's comment, to make sure "init" will never execute twice.) See Szczepan's explanation of why Victor's technique won't work with opcode.cache.

If you ARE using opcode.cache, then AFAIK my answer is as clean as you can get. The cost is simply adding the line MyClass::init(); at start of every public method. NOTE: If you want public properties, code them as a get / set pair of methods, so that you have a place to add that init call.

(Private members do NOT need that init call, as they are not reachable from the outside - so some public method has already been called, by the time execution reaches the private member.)

What does void* mean and how to use it?

C is remarkable in this regard. One can say void is nothingness void* is everything (can be everything).

It's just this tiny * which makes the difference.

Rene has pointed it out. A void * is a Pointer to some location. What there is how to "interpret" is left to the user.

It's the only way to have opaque types in C. Very prominent examples can be found e.g in glib or general data structure libraries. It's treated very detailed in "C Interfaces and implementations".

I suggest you read the complete chapter and try to understand the concept of a pointer to "get it".

php $_GET and undefined index

Actually none of the proposed answers, although a good practice, would remove the warning.

For the sake of correctness, I'd do the following:

function getParameter($param, $defaultValue) {
    if (array_key_exists($param, $_GET)) {
        $value=$_GET[$param];
        return isSet($value)?$value:$defaultValue;
    }
    return $defaultValue;
}

This way, I check the _GET array for the key to exist without triggering the Warning. It's not a good idea to disable the warnings because a lot of times they are at least interesting to take a look.

To use the function you just do:

$myvar = getParameter("getparamer", "defaultValue")

so if the parameter exists, you get the value, and if it doesnt, you get the defaultValue.

UIButton title text color

In Swift:

Changing the label text color is quite different than changing it for a UIButton. To change the text color for a UIButton use this method:

self.headingButton.setTitleColor(UIColor(red: 107.0/255.0, green: 199.0/255.0, blue: 217.0/255.0), forState: UIControlState.Normal)

ImportError: No module named pythoncom

You are missing the pythoncom package. It comes with ActivePython but you can get it separately on GitHub (previously on SourceForge) as part of pywin32.

You can also simply use:

pip install pywin32

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.

Pass Multiple Parameters to jQuery ajax call

Just to add on [This line perfectly work in Asp.net& find web-control Fields in jason Eg:<%Fieldname%>]

 data: "{LocationName:'" + document.getElementById('<%=txtLocationName.ClientID%>').value + "',AreaID:'" + document.getElementById('<%=DropDownArea.ClientID%>').value + "'}",

How to get ID of button user just clicked?

You can also try this simple one-liner code. Just call the alert method on onclick attribute.

<button id="some_id1" onclick="alert(this.id)"></button>

Pointers in Python?

The following code emulates exactly the behavior of pointers in C:

from collections import deque # more efficient than list for appending things
pointer_storage = deque()
pointer_address = 0

class new:    
    def __init__(self):
        global pointer_storage    
        global pointer_address

        self.address = pointer_address
        self.val = None        
        pointer_storage.append(self)
        pointer_address += 1


def get_pointer(address):
    return pointer_storage[address]

def get_address(p):
    return p.address

null = new() # create a null pointer, whose address is 0    

Here are examples of use:

p = new()
p.val = 'hello'
q = new()
q.val = p
r = new()
r.val = 33

p = get_pointer(3)
print(p.val, flush = True)
p.val = 43
print(get_pointer(3).val, flush = True)

But it's now time to give a more professional code, including the option of deleting pointers, that I've just found in my personal library:

# C pointer emulation:

from collections import deque # more efficient than list for appending things
from sortedcontainers import SortedList #perform add and discard in log(n) times


class new:      
    # C pointer emulation:
    # use as : p = new()
    #          p.val             
    #          p.val = something
    #          p.address
    #          get_address(p) 
    #          del_pointer(p) 
    #          null (a null pointer)

    __pointer_storage__ = SortedList(key = lambda p: p.address)
    __to_delete_pointers__ = deque()
    __pointer_address__ = 0 

    def __init__(self):      

        self.val = None 

        if new.__to_delete_pointers__:
            p = new.__to_delete_pointers__.pop()
            self.address = p.address
            new.__pointer_storage__.discard(p) # performed in log(n) time thanks to sortedcontainers
            new.__pointer_storage__.add(self)  # idem

        else:
            self.address = new.__pointer_address__
            new.__pointer_storage__.add(self)
            new.__pointer_address__ += 1


def get_pointer(address):
    return new.__pointer_storage__[address]


def get_address(p):
    return p.address


def del_pointer(p):
    new.__to_delete_pointers__.append(p)

null = new() # create a null pointer, whose address is 0

find index of an int in a list

Use the .IndexOf() method of the list. Specs for the method can be found on MSDN.

How can I replace non-printable Unicode characters in Java?

I have used this simple function for this:

private static Pattern pattern = Pattern.compile("[^ -~]");
private static String cleanTheText(String text) {
    Matcher matcher = pattern.matcher(text);
    if ( matcher.find() ) {
        text = text.replace(matcher.group(0), "");
    }
    return text;
}

Hope this is useful.

Invalid self signed SSL cert - "Subject Alternative Name Missing"

  • Make a copy of your OpenSSL config in your home directory:

    cp /System/Library/OpenSSL/openssl.cnf ~/openssl-temp.cnf
    

    or on Linux:

    cp /etc/ssl/openssl.cnf ~/openssl-temp.cnf
    
  • Add Subject Alternative Name to openssl-temp.cnf, under [v3_ca]:

    [ v3_ca ]
    subjectAltName = DNS:localhost
    

    Replace localhost by the domain for which you want to generate that certificate.

  • Generate certificate:

    sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
        -config ~/openssl-temp.cnf
        -keyout /path/to/your.key -out /path/to/your.crt
    

You can then delete openssl-temp.cnf

What's the purpose of META-INF?

The META-INF folder is the home for the MANIFEST.MF file. This file contains meta data about the contents of the JAR. For example, there is an entry called Main-Class that specifies the name of the Java class with the static main() for executable JAR files.

How can we stop a running java process through Windows cmd?

You can do this with PowerShell:

$process = Start-Process "javaw" "-jar start.jar" -PassThru
taskkill /pid $process.Id

The taskkill command will graceful close the application.

Dropping Unique constraint from MySQL table

A unique constraint is also an index.

First use SHOW INDEX FROM tbl_name to find out the name of the index. The name of the index is stored in the column called key_name in the results of that query.

Then you can use DROP INDEX:

DROP INDEX index_name ON tbl_name

or the ALTER TABLE syntax:

ALTER TABLE tbl_name DROP INDEX index_name

Make Vim show ALL white spaces as a character

The code below is based on Christian Brabandt's answer and seems to do what the OP wants:

function! Whitespace()
    if !exists('b:ws')
        highlight Conceal ctermbg=NONE ctermfg=240 cterm=NONE guibg=NONE guifg=#585858 gui=NONE
        highlight link Whitespace Conceal
        let b:ws = 1
    endif

    syntax clear Whitespace
    syntax match Whitespace / / containedin=ALL conceal cchar=·
    setlocal conceallevel=2 concealcursor=c
endfunction

augroup Whitespace
    autocmd!
    autocmd BufEnter,WinEnter * call Whitespace()
augroup END

Append those lines to your ~/.vimrc and start a new Vim session to see the still imperfect magic happen.

Feel free to edit the default colors and conceal character.


Caveat: something in the *FuncBody syntax group in several languages prevents the middle dot from showing. I don't know (yet?) how to make that solution more reliable.

C#: How would I get the current time into a string?

string t = DateTime.Now.ToString("h/m/s tt");
string t2 = DateTime.Now.ToString("hh:mm:ss tt");
string d = DateTime.Now.ToString("MM/dd/yy");

http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx

Add attribute 'checked' on click jquery

If .attr() isn't working for you (especially when checking and unchecking boxes in succession), use .prop() instead of .attr().

Excel 2013 horizontal secondary axis

You should follow the guidelines on Add a secondary horizontal axis:

Add a secondary horizontal axis

To complete this procedure, you must have a chart that displays a secondary vertical axis. To add a secondary vertical axis, see Add a secondary vertical axis.

  1. Click a chart that displays a secondary vertical axis. This displays the Chart Tools, adding the Design, Layout, and Format tabs.

  2. On the Layout tab, in the Axes group, click Axes.

    enter image description here

  3. Click Secondary Horizontal Axis, and then click the display option that you want.

enter image description here


Add a secondary vertical axis

You can plot data on a secondary vertical axis one data series at a time. To plot more than one data series on the secondary vertical axis, repeat this procedure for each data series that you want to display on the secondary vertical axis.

  1. In a chart, click the data series that you want to plot on a secondary vertical axis, or do the following to select the data series from a list of chart elements:

    • Click the chart.

      This displays the Chart Tools, adding the Design, Layout, and Format tabs.

    • On the Format tab, in the Current Selection group, click the arrow in the Chart Elements box, and then click the data series that you want to plot along a secondary vertical axis.

      enter image description here

  2. On the Format tab, in the Current Selection group, click Format Selection. The Format Data Series dialog box is displayed.

    Note: If a different dialog box is displayed, repeat step 1 and make sure that you select a data series in the chart.

  3. On the Series Options tab, under Plot Series On, click Secondary Axis and then click Close.

    A secondary vertical axis is displayed in the chart.

  4. To change the display of the secondary vertical axis, do the following:

    • On the Layout tab, in the Axes group, click Axes.

    • Click Secondary Vertical Axis, and then click the display option that you want.

  5. To change the axis options of the secondary vertical axis, do the following:

    • Right-click the secondary vertical axis, and then click Format Axis.

    • Under Axis Options, select the options that you want to use.

git stash and git pull

When you have changes on your working copy, from command line do:

git stash 

This will stash your changes and clear your status report

git pull

This will pull changes from upstream branch. Make sure it says fast-forward in the report. If it doesn't, you are probably doing an unintended merge

git stash pop

This will apply stashed changes back to working copy and remove the changes from stash unless you have conflicts. In the case of conflict, they will stay in stash so you can start over if needed.

if you need to see what is in your stash

git stash list

How can I create a "Please Wait, Loading..." animation using jQuery?

If you are using Turbolinks With Rails this is my solution:

This is the CoffeeScript

$(window).on 'page:fetch', ->
  $('body').append("<div class='modal'></div>")
  $('body').addClass("loading")

$(window).on 'page:change', ->
  $('body').removeClass("loading")

This is the SASS CSS based on the first excellent answer from Jonathan Sampson

# loader.css.scss

.modal {
    display:    none;
    position:   fixed;
    z-index:    1000;
    top:        0;
    left:       0;
    height:     100%;
    width:      100%;
    background: rgba( 255, 255, 255, 0.4)
            asset-url('ajax-loader.gif', image)
            50% 50% 
            no-repeat;
}
body.loading {
    overflow: hidden;   
}

body.loading .modal {
    display: block;
}

File input 'accept' attribute - is it useful?

Accept attribute was introduced in the RFC 1867, intending to enable file-type filtering based on MIME type for the file-select control. But as of 2008, most, if not all, browsers make no use of this attribute. Using client-side scripting, you can make a sort of extension based validation, for submit data of correct type (extension).

Other solutions for advanced file uploading require Flash movies like SWFUpload or Java Applets like JUpload.

How can I generate random alphanumeric strings?

Very simple solution. It uses ASCII values and just generates "random" characters in between them.

public static class UsernameTools
{
    public static string GenerateRandomUsername(int length = 10)
    {
        Random random = new Random();
        StringBuilder sbuilder = new StringBuilder();
        for (int x = 0; x < length; ++x)
        {
            sbuilder.Append((char)random.Next(33, 126));
        }
        return sbuilder.ToString();
    }

}

How to count items in JSON data

You're close. A really simple solution is just to get the length from the 'run' objects returned. No need to bother with 'load' or 'loads':

len(data['result'][0]['run'])

How to change environment's font size?

A Simple approach to change the Font Size in Visual Studio Work Environment :

Go To : File -> Preferences -> Settings OR Press CTRL+, i.e. CTRL + COMMA.

This will open settings.json.

You can see 3 tabs there :

  1. User Settings
  2. Workspace Settings
  3. Folder Settings

Go to User Settings and Add this :

{
"editor.fontSize": 16
}

Now just save and close the file.

In above code, 16 represents the font size. Increase of Decrease as per your wish.

Could not load file or assembly 'System.Net.Http.Formatting' or one of its dependencies. The system cannot find the path specified

user3919888 pointed me in the right direction, but I needed to run Update-Package -reinstall Microsoft.AspNet.WebApi.Client in the Package-Manager console. Basic install by itself does not recognize the problem but does recognize that the package is already installed and does not overwrite it.

I'm posting this answer because this happens so infrequently that I end up googling and reaching this page before I remember what I did last time.

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

The next steps after resolving the conflicts manually are:-

  1. git add .
  2. git status (this will show you which commands are necessary to continue automatic merge procedure)
  3. [command git suggests, e.g. git merge --continue, git cherry-pick --continue, git rebase --continue]

How to change text color and console color in code::blocks?

You can also use rlutil:

  • cross platform,
  • header only (rlutil.h),
  • works for C and C++,
  • implements setColor(), cls(), getch(), gotoxy(), etc.
  • License: WTFPL

Your code would become something like this:

#include <stdio.h>

#include "rlutil.h"

int main(int argc, char* argv[])
{
    setColor(BLUE);
    printf("\n \n \t This is dummy program for text color ");
    getch();

    return 0;
}

Have a look at example.c and test.cpp for C and C++ examples.

How to connect Bitbucket to Jenkins properly

I had a similar problems, till I got it working. Below is the full listing of the integration:

  1. Generate public/private keys pair: ssh-keygen -t rsa
  2. Copy the public key (~/.ssh/id_rsa.pub) and paste it in Bitbucket SSH keys, in user’s account management console: enter image description here

  3. Copy the private key (~/.ssh/id_rsa) to new user (or even existing one) with private key credentials, in this case, username will not make a difference, so username can be anything: enter image description here

  4. run this command to test if you can get access to Bitbucket account: ssh -T [email protected]

  5. OPTIONAL: Now, you can use your git to to copy repo to your desk without passwjord git clone [email protected]:username/repo_name.git
  6. Now you can enable Bitbucket hooks for Jenkins push notifications and automatic builds, you will do that in 2 steps:

    1. Add an authentication token inside the job/project you configure, it can be anything: enter image description here

    2. In Bitbucket hooks: choose jenkins hooks, and fill the fields as below: enter image description here

Where:

**End point**: username:usertoken@jenkins_domain_or_ip
**Project name**: is the name of job you created on Jenkins
**Token**: Is the authorization token you added in the above steps in your Jenkins' job/project 

Recommendation: I usually add the usertoken as the authorization Token (in both Jenkins Auth Token job configuration and Bitbucket hooks), making them one variable to ease things on myself.

RESTful Authentication

First and foremost, a RESTful web service is STATELESS (or in other words, SESSIONLESS). Therefore, a RESTful service does not have and should not have a concept of session or cookies involved. The way to do authentication or authorization in the RESTful service is by using the HTTP Authorization header as defined in the RFC 2616 HTTP specifications. Every single request should contain the HTTP Authorization header, and the request should be sent over an HTTPs (SSL) connection. This is the correct way to do authentication and to verify the authorization of requests in a HTTP RESTful web services. I have implemented a RESTful web service for the Cisco PRIME Performance Manager application at Cisco Systems. And as part of that web service, I have implemented authentication/authorization as well.

When to use the !important property in CSS

You use !important to override a css property.

For example, you have a control in ASP.NET and it renders a control with a background blue (in the HTML). You want to change it, and you don't have the source control so you attach a new CSS file and write the same selector and change the color and after it add !important.

Best practices is when you are branding / redesigning SharePoint sites, you use it a lot to override the default styles.

Format LocalDateTime with Timezone in Java8

LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyyMMdd HH:mm:ss.SSSSSS Z"));

.NET code to send ZPL to Zebra printers

VB Version (using port 9100 - tested on Zebra ZM400)

Sub PrintZPL(ByVal pIP As String, ByVal psZPL As String)
    Dim lAddress As Net.IPEndPoint
    Dim lSocket As System.Net.Sockets.Socket = Nothing
    Dim lNetStream As System.Net.Sockets.NetworkStream = Nothing
    Dim lBytes As Byte()

    Try
        lAddress = New Net.IPEndPoint(Net.IPAddress.Parse(pIP), 9100)
        lSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, _                       ProtocolType.Tcp)
        lSocket.Connect(lAddress)
        lNetStream = New NetworkStream(lSocket)

        lBytes = System.Text.Encoding.ASCII.GetBytes(psZPL)
        lNetStream.Write(lBytes, 0, lBytes.Length)
    Catch ex As Exception When Not App.Debugging
        Msgbox ex.message & vbnewline & ex.tostring
    Finally
        If Not lNetStream Is Nothing Then
            lNetStream.Close()
        End If
        If Not lSocket Is Nothing Then
            lSocket.Close()
        End If
    End Try
End Sub

Use multiple css stylesheets in the same html page

The one you include last will be the one that is used. Note however that if any rules has !important in the first stylesheet they will take priority.

How to use "/" (directory separator) in both Linux and Windows in Python?

os.path.normpath(pathname) should also be mentioned as it converts / path separators into \ separators on Windows. It also collapses redundant uplevel references... i.e., A/B and A/foo/../B and A/./B all become A/B. And if you are Windows, these all become A\B.

What is the difference between supervised learning and unsupervised learning?

Supervised Machine Learning

"The process of an algorithm learning from training dataset and predict the output. "

Accuracy of predicted output directly proportional to the training data (length)

Supervised learning is where you have input variables (x) (training dataset) and an output variable (Y) (testing dataset) and you use an algorithm to learn the mapping function from the input to the output.

Y = f(X)

Major types:

  • Classification (discrete y-axis)
  • Predictive (continuous y-axis)

Algorithms:

  • Classification Algorithms:

    Neural Networks  
    Naïve Bayes classifiers  
    Fisher linear discriminant  
    KNN 
    Decision Tree 
    Super Vector Machines
    
  • Predictive Algorithms:

    Nearest  neighbor  
    Linear Regression,Multi Regression 
    

Application areas:

  1. Classifying emails as spam
  2. Classifying whether patient has disease or not
  3. Voice Recognition

  4. Predict the HR select particular candidate or not

  5. Predict the stock market price

What requests do browsers' "F5" and "Ctrl + F5" refreshes generate?

I've implemented cross-browser compatible page to test browser's refresh behavior (here is the source code) and get results similar to @some, but for modern browsers:

enter image description here

configuring project ':app' failed to find Build Tools revision

For me, dataBinding { enabled true } was enabled in gradle, removing this helped me

Resizing SVG in html?

I have an SVG file in HTML [....] IS there any way to specify that you want an SVG image displayed smaller or larger than it actually is stored in the file system?

SVG graphics, like other creative works, are protected under copyright law in most countries. Depending on jurisdiction, license of the work or whether or not you are the copyright holder you may not be able to modify the SVG without violating copyright law, believe it or not.

But laws are tricky topics and sometimes you just want to get shit done. Therefore you may adjust the scale of the graphic without modifying the work itself using the img tag with width attribute within your HTML.

Using an external HTTP request to specify the size:

<img width="96" src="/path/to/image.svg">

Specifying size in markup using a Data URI:

<img width="96" src="data:image/svg+xml,...">

SVGs can be Optimized for Data URIs to create SVG Favicon images suitable for any size:

<link rel="icon" sizes="any" href="data:image/svg+xml,%3Csvg%20viewBox='0%200%2046%2045'%20xmlns='http://www.w3.org/2000/svg'%3E%3Ctitle%3EAfter%20Dark%3C/title%3E%3Cpath%20d='M.708%2045L23%20.416%2045.292%2045H.708zM35%2038L23%2019%2011%2038h24z'%20fill='%23000'/%3E%3C/svg%3E">

What does the red exclamation point icon in Eclipse mean?

According to the documentation:

Decorates Java projects and working sets that contain build path errors

In practice, I've found that a "build path error" may be caused by any number of reasons, depending on what plugins are active. Check the "Problems" view for more information.

Adding open/closed icon to Twitter Bootstrap collapsibles (accordions)

Here is my approach for Bootstrap 2.x. It is just some css. No JavaScript needed:

    .accordion-caret .accordion-toggle:hover {
        text-decoration: none;
    }
    .accordion-caret .accordion-toggle:hover span,
    .accordion-caret .accordion-toggle:hover strong {
        text-decoration: underline;
    }
    .accordion-caret .accordion-toggle:before {
        font-size: 25px;
        vertical-align: -3px;
    }
    .accordion-caret .accordion-toggle:not(.collapsed):before {
        content: "?";
        margin-right: 0px;
    }
    .accordion-caret .accordion-toggle.collapsed:before {
        content: "?";
        margin-right: 0px;
    }

Just add class accordion-caret to the accordion-group div, like this:

<div class="accordion-group accordion-caret">
    <div class="accordion-heading">
        <a class="accordion-toggle" data-toggle="collapse" href="#collapseOne">
            <strong>Header</strong>
        </a>
    </div>
    <div id="collapseOne" class="accordion-body collapse in">
        <div class="accordion-inner">
            Content
        </div>
    </div>
</div>

Select folder dialog WPF

Add The Windows API Code Pack-Shell to your project

using Microsoft.WindowsAPICodePack.Dialogs;

...

var dialog = new CommonOpenFileDialog();
dialog.IsFolderPicker = true;
CommonFileDialogResult result = dialog.ShowDialog();

Why did I get the compile error "Use of unassigned local variable"?

See this thread concerning uninitialized bools, but it should answer your question.

Local variables are not initialized unless you call their constructors (new) or assign them a value.

Synchronously waiting for an async operation, and why does Wait() freeze the program here

With small custom synchronization context, sync function can wait for completion of async function, without creating deadlock. Here is small example for WinForms app.

Imports System.Threading
Imports System.Runtime.CompilerServices

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        SyncMethod()
    End Sub

    ' waiting inside Sync method for finishing async method
    Public Sub SyncMethod()
        Dim sc As New SC
        sc.WaitForTask(AsyncMethod())
        sc.Release()
    End Sub

    Public Async Function AsyncMethod() As Task(Of Boolean)
        Await Task.Delay(1000)
        Return True
    End Function

End Class

Public Class SC
    Inherits SynchronizationContext

    Dim OldContext As SynchronizationContext
    Dim ContextThread As Thread

    Sub New()
        OldContext = SynchronizationContext.Current
        ContextThread = Thread.CurrentThread
        SynchronizationContext.SetSynchronizationContext(Me)
    End Sub

    Dim DataAcquired As New Object
    Dim WorkWaitingCount As Long = 0
    Dim ExtProc As SendOrPostCallback
    Dim ExtProcArg As Object

    <MethodImpl(MethodImplOptions.Synchronized)>
    Public Overrides Sub Post(d As SendOrPostCallback, state As Object)
        Interlocked.Increment(WorkWaitingCount)
        Monitor.Enter(DataAcquired)
        ExtProc = d
        ExtProcArg = state
        AwakeThread()
        Monitor.Wait(DataAcquired)
        Monitor.Exit(DataAcquired)
    End Sub

    Dim ThreadSleep As Long = 0

    Private Sub AwakeThread()
        If Interlocked.Read(ThreadSleep) > 0 Then ContextThread.Resume()
    End Sub

    Public Sub WaitForTask(Tsk As Task)
        Dim aw = Tsk.GetAwaiter

        If aw.IsCompleted Then Exit Sub

        While Interlocked.Read(WorkWaitingCount) > 0 Or aw.IsCompleted = False
            If Interlocked.Read(WorkWaitingCount) = 0 Then
                Interlocked.Increment(ThreadSleep)
                ContextThread.Suspend()
                Interlocked.Decrement(ThreadSleep)
            Else
                Interlocked.Decrement(WorkWaitingCount)
                Monitor.Enter(DataAcquired)
                Dim Proc = ExtProc
                Dim ProcArg = ExtProcArg
                Monitor.Pulse(DataAcquired)
                Monitor.Exit(DataAcquired)
                Proc(ProcArg)
            End If
        End While

    End Sub

     Public Sub Release()
         SynchronizationContext.SetSynchronizationContext(OldContext)
     End Sub

End Class

receiving error: 'Error: SSL Error: SELF_SIGNED_CERT_IN_CHAIN' while using npm

You need to upgrade npm.

// Do this first, or the upgrade will fail
npm config set ca ""

npm install npm -g

// Undo the previous config change
npm config delete ca

You may need to prefix those commands with sudo.

Source: http://blog.npmjs.org/post/78085451721/npms-self-signed-certificate-is-no-more

Simple prime number generator in Python

Another simple example, with a simple optimization of only considering odd numbers. Everything done with lazy streams (python generators).

Usage: primes = list(create_prime_iterator(1, 30))

import math
import itertools

def create_prime_iterator(rfrom, rto):
    """Create iterator of prime numbers in range [rfrom, rto]"""
    prefix = [2] if rfrom < 3 and rto > 1 else [] # include 2 if it is in range separately as it is a "weird" case of even prime
    odd_rfrom = 3 if rfrom < 3 else make_odd(rfrom) # make rfrom an odd number so that  we can skip all even nubers when searching for primes, also skip 1 as a non prime odd number.
    odd_numbers = (num for num in xrange(odd_rfrom, rto + 1, 2))
    prime_generator = (num for num in odd_numbers if not has_odd_divisor(num))
    return itertools.chain(prefix, prime_generator)

def has_odd_divisor(num):
    """Test whether number is evenly divisable by odd divisor."""
    maxDivisor = int(math.sqrt(num))
    for divisor in xrange(3, maxDivisor + 1, 2):
        if num % divisor == 0:
            return True
    return False

def make_odd(number):
    """Make number odd by adding one to it if it was even, otherwise return it unchanged"""
    return number | 1

Bulk insert with SQLAlchemy ORM

The sqlalchemy docs have a writeup on the performance of various techniques that can be used for bulk inserts:

ORMs are basically not intended for high-performance bulk inserts - this is the whole reason SQLAlchemy offers the Core in addition to the ORM as a first-class component.

For the use case of fast bulk inserts, the SQL generation and execution system that the ORM builds on top of is part of the Core. Using this system directly, we can produce an INSERT that is competitive with using the raw database API directly.

Alternatively, the SQLAlchemy ORM offers the Bulk Operations suite of methods, which provide hooks into subsections of the unit of work process in order to emit Core-level INSERT and UPDATE constructs with a small degree of ORM-based automation.

The example below illustrates time-based tests for several different methods of inserting rows, going from the most automated to the least. With cPython 2.7, runtimes observed:

classics-MacBook-Pro:sqlalchemy classic$ python test.py
SQLAlchemy ORM: Total time for 100000 records 12.0471920967 secs
SQLAlchemy ORM pk given: Total time for 100000 records 7.06283402443 secs
SQLAlchemy ORM bulk_save_objects(): Total time for 100000 records 0.856323003769 secs
SQLAlchemy Core: Total time for 100000 records 0.485800027847 secs
sqlite3: Total time for 100000 records 0.487842082977 sec

Script:

import time
import sqlite3

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String,  create_engine
from sqlalchemy.orm import scoped_session, sessionmaker

Base = declarative_base()
DBSession = scoped_session(sessionmaker())
engine = None


class Customer(Base):
    __tablename__ = "customer"
    id = Column(Integer, primary_key=True)
    name = Column(String(255))


def init_sqlalchemy(dbname='sqlite:///sqlalchemy.db'):
    global engine
    engine = create_engine(dbname, echo=False)
    DBSession.remove()
    DBSession.configure(bind=engine, autoflush=False, expire_on_commit=False)
    Base.metadata.drop_all(engine)
    Base.metadata.create_all(engine)


def test_sqlalchemy_orm(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    for i in xrange(n):
        customer = Customer()
        customer.name = 'NAME ' + str(i)
        DBSession.add(customer)
        if i % 1000 == 0:
            DBSession.flush()
    DBSession.commit()
    print(
        "SQLAlchemy ORM: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")


def test_sqlalchemy_orm_pk_given(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    for i in xrange(n):
        customer = Customer(id=i+1, name="NAME " + str(i))
        DBSession.add(customer)
        if i % 1000 == 0:
            DBSession.flush()
    DBSession.commit()
    print(
        "SQLAlchemy ORM pk given: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")


def test_sqlalchemy_orm_bulk_insert(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    n1 = n
    while n1 > 0:
        n1 = n1 - 10000
        DBSession.bulk_insert_mappings(
            Customer,
            [
                dict(name="NAME " + str(i))
                for i in xrange(min(10000, n1))
            ]
        )
    DBSession.commit()
    print(
        "SQLAlchemy ORM bulk_save_objects(): Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")


def test_sqlalchemy_core(n=100000):
    init_sqlalchemy()
    t0 = time.time()
    engine.execute(
        Customer.__table__.insert(),
        [{"name": 'NAME ' + str(i)} for i in xrange(n)]
    )
    print(
        "SQLAlchemy Core: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " secs")


def init_sqlite3(dbname):
    conn = sqlite3.connect(dbname)
    c = conn.cursor()
    c.execute("DROP TABLE IF EXISTS customer")
    c.execute(
        "CREATE TABLE customer (id INTEGER NOT NULL, "
        "name VARCHAR(255), PRIMARY KEY(id))")
    conn.commit()
    return conn


def test_sqlite3(n=100000, dbname='sqlite3.db'):
    conn = init_sqlite3(dbname)
    c = conn.cursor()
    t0 = time.time()
    for i in xrange(n):
        row = ('NAME ' + str(i),)
        c.execute("INSERT INTO customer (name) VALUES (?)", row)
    conn.commit()
    print(
        "sqlite3: Total time for " + str(n) +
        " records " + str(time.time() - t0) + " sec")

if __name__ == '__main__':
    test_sqlalchemy_orm(100000)
    test_sqlalchemy_orm_pk_given(100000)
    test_sqlalchemy_orm_bulk_insert(100000)
    test_sqlalchemy_core(100000)
    test_sqlite3(100000)

onclick event function in JavaScript

Two observations:

  1. You should write

    <input type="button" value="button text" />
    

    instead of

    <input type="button">button text</input>
    
  2. You should rename your function. The function click() is already defined on a button (it simulates a click), and gets a higher priority then your method.

Note that there are a couple of suggestions here that are plain wrong, and you shouldn't spend to much time on them:

  • Do not use onclick="javascript:myfunc()". Only use the javascript: prefix inside the href attribute of a hyperlink: <a href="javascript:myfunc()">.
  • You don't have to end with a semicolon. onclick="foo()" and onclick="foo();" both work just fine.
  • Event attributes in HTML are not case sensitive, so onclick, onClick and ONCLICK all work. It is common practice to write attributes in lowercase: onclick. note that javascript itself is case sensitive, so if you write document.getElementById("...").onclick = ..., then it must be all lowercase.

ip address validation in python using regex

The following will check whether an IP is valid or not: If the IP is within 0.0.0.0 to 255.255.255.255, then the output will be true, otherwise it will be false:

[0<=int(x)<256 for x in re.split('\.',re.match(r'^\d+\.\d+\.\d+\.\d+$',your_ip).group(0))].count(True)==4

Example:

your_ip = "10.10.10.10"
[0<=int(x)<256 for x in re.split('\.',re.match(r'^\d+\.\d+\.\d+\.\d+$',your_ip).group(0))].count(True)==4

Output:

>>> your_ip = "10.10.10.10"
>>> [0<=int(x)<256 for x in re.split('\.',re.match(r'^\d+\.\d+\.\d+\.\d+$',your_ip).group(0))].count(True)==4
True
>>> your_ip = "10.10.10.256"
>>> [0<=int(x)<256 for x in re.split('\.',re.match(r'^\d+\.\d+\.\d+\.\d+$',your_ip).group(0))].count(True)==4
False
>>>

Get GPS location from the web browser

To give a bit more specific answer. HTML5 allows you to get the geo coordinates, and it does a pretty decent job. Overall the browser support for geolocation is pretty good, all major browsers except ie7 and ie8 (and opera mini). IE9 does the job but is the worst performer. Checkout caniuse.com:

http://caniuse.com/#search=geol

Also you need the approval of your user to access their location, so make sure you check for this and give some decent instructions in case it's turned off. Especially for Iphone turning permissions on for Safari is a bit cumbersome.

Merge 2 arrays of objects

Posting this because unlike the previous answers this one is generic, no external libraries, O(n), actually filters out the duplicate and keeps the order the OP is asking for (by placing the last matching element in place of first appearance):

function unique(array, keyfunc) {
    return array.reduce((result, entry) => {
        const key = keyfunc(entry)
        if(key in result.seen) {
            result.array[result.seen[key]] = entry
        } else {
            result.seen[key] = result.array.length
            result.array.push(entry)
        }
        return result
    }, { array: [], seen: {}}).array
}

Usage:

var arr1 = new Array({name: "lang", value: "English"}, {name: "age", value: "18"})
var arr2 = new Array({name : "childs", value: '5'}, {name: "lang", value: "German"})

var arr3 = unique([...arr1, ...arr2], x => x.name)
/* arr3 == [ 
    {name: "lang", value: "German"}, 
    {name: "age", value: "18"},
    {name: "childs", value: "5"}
]*/

Error:java: invalid source release: 8 in Intellij. What does it mean?

I had the same issue the solution for me was to change my java version in the pom.xml file.

I changed it from 11 to 8. enter image description here

Typescript react - Could not find a declaration file for module ''react-materialize'. 'path/to/module-name.js' implicitly has an any type

Could not find a declaration file for module 'react/jsx-runtime'

If someone's having this error, then you'll be surprised to know that when creating react app with create-react-app, it only shows @types/react in package.json. But if you check inside the node_modules/@types folder, you'll not find any folder of react.

Solution is to just wipe out the node_modules folder completely and reinstall - npm install or maybe can go with the individual module installation - npm install @types/react.

How to make a div center align in HTML

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
  <head>_x000D_
    <title>Center</title>_x000D_
  </head>_x000D_
  <body>_x000D_
_x000D_
    <div style="text-align: center;">_x000D_
      <div style="width: 500px; margin: 0 auto; background: #000; color: #fff;">This DIV is centered</div>_x000D_
    </div>_x000D_
_x000D_
  </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Tested and worked in IE, Firefox, Chrome, Safari and Opera. I did not test IE6. The outer text-align is needed for IE. Other browsers (and IE9?) will work when you give the DIV margin (left and right) value of auto. Margin "0 auto" is a shorthand for margin "0 auto 0 auto" (top right bottom left).

Note: the text is also centered inside the inner DIV, if you want it to remain on the left side just specify text-align: left; for the inner DIV.

Edit: IE 6, 7, 8 and 9 running on the Standards Mode will work with margins set to auto.

How can I use optional parameters in a T-SQL stored procedure?

Dynamically changing searches based on the given parameters is a complicated subject and doing it one way over another, even with only a very slight difference, can have massive performance implications. The key is to use an index, ignore compact code, ignore worrying about repeating code, you must make a good query execution plan (use an index).

Read this and consider all the methods. Your best method will depend on your parameters, your data, your schema, and your actual usage:

Dynamic Search Conditions in T-SQL by by Erland Sommarskog

The Curse and Blessings of Dynamic SQL by Erland Sommarskog

If you have the proper SQL Server 2008 version (SQL 2008 SP1 CU5 (10.0.2746) and later), you can use this little trick to actually use an index:

Add OPTION (RECOMPILE) onto your query, see Erland's article, and SQL Server will resolve the OR from within (@LastName IS NULL OR LastName= @LastName) before the query plan is created based on the runtime values of the local variables, and an index can be used.

This will work for any SQL Server version (return proper results), but only include the OPTION(RECOMPILE) if you are on SQL 2008 SP1 CU5 (10.0.2746) and later. The OPTION(RECOMPILE) will recompile your query, only the verison listed will recompile it based on the current run time values of the local variables, which will give you the best performance. If not on that version of SQL Server 2008, just leave that line off.

CREATE PROCEDURE spDoSearch
    @FirstName varchar(25) = null,
    @LastName varchar(25) = null,
    @Title varchar(25) = null
AS
    BEGIN
        SELECT ID, FirstName, LastName, Title
        FROM tblUsers
        WHERE
                (@FirstName IS NULL OR (FirstName = @FirstName))
            AND (@LastName  IS NULL OR (LastName  = @LastName ))
            AND (@Title     IS NULL OR (Title     = @Title    ))
        OPTION (RECOMPILE) ---<<<<use if on for SQL 2008 SP1 CU5 (10.0.2746) and later
    END

Adding 30 minutes to time formatted as H:i in PHP

What you need is a datetime which is 30 minutes later than your given datetime, and a datetime which is 30 minutes before a given datetime. In other words, you need a future datetime and a past datetime. Hence, classes that achieve that are called Future and Past. What data do they need to calculate what you need? Apparently, they must have a datetime relative to which to count those 30 minutes, and an interval itself -- 30 minutes in your case. Thus, the desired datetime looks like the following:

use Meringue\ISO8601DateTime\FromCustomFormat as DateTimeCreatedFromCustomFormat;

(new Future(
    new DateTimeCreatedFromCustomFormat('H:i', '10:00'),
    new NMinutes(30)
))
    ->value();

If you want to format it somehow, you can do:

use Meringue\ISO8601DateTime\FromCustomFormat as DateTimeCreatedFromCustomFormat;

(new ISO8601Formatted(
    new Future(
        new DateTimeCreatedFromCustomFormat('H:i', '10:00'),
        new NMinutes(30)
    ),
    'H:i'
))
    ->value();

It's more verbose, but I guess it's way less cryptic than built-in php functions.

If you liked this approach, you can learn some more about the meringue library used in this example, and the overall approach.

How to mount the android img file under linux?

I have found a simple solution: http://andwise.net/?p=403

Quote

(with slight adjustments for better readability)


This is for all who want to unpack and modify the original system.img that you can flash using recovery. system.img (which you get from the google factory images for example) represents a sparse ext4 loop mounted file system. It is mounted into /system of your device. Note that this tutorial is for ext4 file system. You may have system image which is yaffs2, for example.

The way it is mounted on Galaxy Nexus:

/dev/block/platform/omap/omap_hsmmc.0/by-name/system /system ext4 ro,relatime,barrier=1,data=ordered 0 0

Prerequisites:

  • Linux box or virtual machine
  • simg2img and make_ext4fs binaries, which can be downloaded from the linux package android-tools-fsutils

Procedure:

Place your system.img and the 2 binaries in one directory, and make sure the binaries have exec permission.

Part 1 – mount the file-system

mkdir sys
./simg2img system.img sys.raw
sudo mount -t ext4 -o loop sys.raw sys/

Then you have your system partition mounted in ‘sys/’ and you can modify whatever you want in ‘sys/’. For example de-odex apks and framework jars.

Part 2 – create a new flashable system image

sudo ./make_ext4fs -s -l 512M -a system new.img sys/
sudo umount sys
rm -fr sys

Now you can simply type:

fastboot flash system new.img

Reset auto increment counter in postgres

The following command does this automatically for you: This will also delete all the data in the table. So be careful.

TRUNCATE TABLE someTable RESTART IDENTITY;

Changing case in Vim

Visual select the text, then U for uppercase or u for lowercase. To swap all casing in a visual selection, press ~ (tilde).

Without using a visual selection, gU<motion> will make the characters in motion uppercase, or use gu<motion> for lowercase.

For more of these, see Section 3 in Vim's change.txt help file.

ASP.NET MVC passing an ID in an ActionLink to the controller

On MVC 5 is quite similar

@Html.ActionLink("LinkText", "ActionName", new { id = "id" })

How to use curl in a shell script?

Firstly, your example is looking quite correct and works well on my machine. You may go another way.

curl $CURLARGS $RVMHTTP > ./install.sh

All output now storing in ./install.sh file, which you can edit and execute.

Find Facebook user (url to profile page) by known email address


WARNING: Old and outdated answer. Do not use


I think that you will have to go for your last solution, scraping the result page of the search, because you can only search by email with the API into those users that have authorized your APP (and you will need one because the token that FB provides in the examples has an expiry date and you need extended permissions to access the user's email).

The only approach that I have not tried, but I think it's limited in the same way, is FQL. Something like

SELECT * FROM user WHERE email '[email protected]'

LISTAGG in Oracle to return distinct values

If you want distinct values across MULTIPLE columns, want control over sort order, don't want to use an undocumented function that may disappear, and do not want more than one full table scan, you may find this construct useful:

with test_data as 
(
      select 'A' as col1, 'T_a1' as col2, '123' as col3 from dual
union select 'A', 'T_a1', '456' from dual
union select 'A', 'T_a1', '789' from dual
union select 'A', 'T_a2', '123' from dual
union select 'A', 'T_a2', '456' from dual
union select 'A', 'T_a2', '111' from dual
union select 'A', 'T_a3', '999' from dual
union select 'B', 'T_a1', '123' from dual
union select 'B', 'T_b1', '740' from dual
union select 'B', 'T_b1', '846' from dual
)
select col1
     , (select listagg(column_value, ',') within group (order by column_value desc) from table(collect_col2)) as col2s
     , (select listagg(column_value, ',') within group (order by column_value desc) from table(collect_col3)) as col3s
from 
(
select col1
     , collect(distinct col2) as collect_col2
     , collect(distinct col3) as collect_col3
from test_data
group by col1
);

VBScript to send email without running Outlook

You can send email without Outlook in VBScript using the CDO.Message object. You will need to know the address of your SMTP server to use this:

Set MyEmail=CreateObject("CDO.Message")

MyEmail.Subject="Subject"
MyEmail.From="[email protected]"
MyEmail.To="[email protected]"
MyEmail.TextBody="Testing one two three."

MyEmail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendusing")=2

'SMTP Server
MyEmail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpserver")="smtp.server.com"

'SMTP Port
MyEmail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpserverport")=25 

MyEmail.Configuration.Fields.Update
MyEmail.Send

set MyEmail=nothing

If your SMTP server requires a username and password then paste these lines in above the MyEmail.Configuration.Fields.Update line:

'SMTP Auth (For Windows Auth set this to 2)
MyEmail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate")=1
'Username
MyEmail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendusername")="username" 
'Password
MyEmail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendpassword")="password"

More information on using CDO to send email with VBScript can be found on the link below: http://www.paulsadowski.com/wsh/cdo.htm

What is the purpose of mvnw and mvnw.cmd files?

These files are from Maven wrapper. It works similarly to the Gradle wrapper.

This allows you to run the Maven project without having Maven installed and present on the path. It downloads the correct Maven version if it's not found (as far as I know by default in your user home directory).

The mvnw file is for Linux (bash) and the mvnw.cmd is for the Windows environment.


To create or update all necessary Maven Wrapper files execute the following command:

mvn -N io.takari:maven:wrapper

To use a different version of maven you can specify the version as follows:

mvn -N io.takari:maven:wrapper -Dmaven=3.3.3

Both commands require maven on PATH (add the path to maven bin to Path on System Variables) if you already have mvnw in your project you can use ./mvnw instead of mvn in the commands.

Creating a range of dates in Python

If there are two dates and you need the range try

from dateutil import rrule, parser
date1 = '1995-01-01'
date2 = '1995-02-28'
datesx = list(rrule.rrule(rrule.DAILY, dtstart=parser.parse(date1), until=parser.parse(date2)))

How do I disable form resizing for users?

Change the FormBorderStyle to one of the fixed values: FixedSingle, Fixed3D, FixedDialog or FixedToolWindow.

The FormBorderStyle property is under the Appearance category.

Or check this:

// Define the border style of the form to a dialog box.
form1.FormBorderStyle = FormBorderStyle.FixedDialog;

// Set the MaximizeBox to false to remove the maximize box.
form1.MaximizeBox = false;

// Set the MinimizeBox to false to remove the minimize box.
form1.MinimizeBox = false;

// Set the start position of the form to the center of the screen.
form1.StartPosition = FormStartPosition.CenterScreen;

// Display the form as a modal dialog box.
form1.ShowDialog();

Select values of checkbox group with jQuery

Use .map() (adapted from the example at http://api.jquery.com/map/):

var values = $("input[name='user_group[]']:checked").map(function(index,domElement) {
    return $(domElement).val();
});

How to clear PermGen space Error in tomcat

To complement Michael's answer, and according to this answer, a safe way to deal with the problem is to use the following arguments:

-XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -XX:+UseConcMarkSweepGC

How to reliably open a file in the same directory as a Python script

After trying all of this solutions, I still had different problems. So what I found the simplest way was to create a python file: config.py, with a dictionary containing the file's absolute path and import it into the script. something like

import config as cfg 
import pandas as pd 
pd.read_csv(cfg.paths['myfilepath'])

where config.py has inside:

paths = {'myfilepath': 'home/docs/...'}

It is not automatic but it is a good solution when you have to work in different directory or different machines.

How can I change the image displayed in a UIImageView programmatically?

If you have an IBOutlet to a UIImageView already, then all you have to do is grab an image and call setImage on the receiver (UIImageView). Two examples of grabbing an image are below. One from the Web, and one you add to your Resources folder in Xcode.

UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://farm4.static.flickr.com/3092/2915896504_a88b69c9de.jpg"]]];

or

UIImage *image = [UIImage imageNamed: @"cell.png"];

Once you have an Image you can then set UIImageView:

[imageView setImage:image];

The line above assumes imageView is your IBOutlet.

That's it! If you want to get fancy you can add the image to an UIView and then add transitions.

P.S. Memory management not included.

Directory index forbidden by Options directive

In my case, it's a typo caused this issue:

<VirtualHost *.8080>

should be

<VirtualHost *:8080>

Looping through a Scripting.Dictionary using index/item number

According to the documentation of the Item property:

Sets or returns an item for a specified key in a Dictionary object.

In your case, you don't have an item whose key is 1 so doing:

s = d.Item(i)

actually creates a new key / value pair in your dictionary, and the value is empty because you have not used the optional newItem argument.

The Dictionary also has the Items method which allows looping over the indices:

a = d.Items
For i = 0 To d.Count - 1
    s = a(i)
Next i

How to check if an integer is in a given range?

That's how you check is an integer is in a range. Greater than the lower bound, less than the upper bound. Trying to be clever with subtraction will likely not do what you want.

html select only one checkbox in a group

If someone need a solution without an external javascript libraries you could use this example. A group of checkboxes allowing 0..1 values. You may click on the checkbox component or associated label text.

    <input id="mygroup1" name="mygroup" type="checkbox" value="1" onclick="toggleRadioCheckbox(this)" /> <label for="mygroup1">Yes</label>
    <input id="mygroup0" name="mygroup" type="checkbox" value="0" onclick="toggleRadioCheckbox(this)" /> <label for="mygroup0">No</label>

- - - - - - - - 

    function toggleRadioCheckbox(sender) {
        // RadioCheckbox: 0..1 enabled in a group 
        if (!sender.checked) return;
        var fields = document.getElementsByName(sender.name);
        for(var idx=0; idx<fields.length; idx++) {
            var field = fields[idx];
            if (field.checked && field!=sender)
                field.checked=false;
        }
    }

PHP file_get_contents() and setting request headers

Unfortunately, it doesn't look like file_get_contents() really offers that degree of control. The cURL extension is usually the first to come up, but I would highly recommend the PECL_HTTP extension (http://pecl.php.net/package/pecl_http) for very simple and straightforward HTTP requests. (it's much easier to work with than cURL)

Rollback one specific migration in Laravel

Every time you rollback you get the last batch of migration. use the command

php artisan migrate:rollback --step=1

How to resolve this JNI error when trying to run LWJGL "Hello World"?

A CLASSPATH entry is either a directory at the head of a package hierarchy of .class files, or a .jar file. If you're expecting ./lib to include all the .jar files in that directory, it won't. You have to name them explicitly.

How can I add an element after another element?

try using the after() method:

$('#bla').after('<div id="space"></div>');

Documentation

C# int to enum conversion

Casting should be enough. If you're using C# 3.0 you can make a handy extension method to parse enum values:

public static TEnum ToEnum<TInput, TEnum>(this TInput value)
{
    Type type = typeof(TEnum);

    if (value == default(TInput))
    {
        throw new ArgumentException("Value is null or empty.", "value");
    }

    if (!type.IsEnum)
    {
        throw new ArgumentException("Enum expected.", "TEnum");
    }

    return (TEnum)Enum.Parse(type, value.ToString(), true);
}

What does it mean by command cd /d %~dp0 in Windows

Let's dissect it. There are three parts:

  1. cd -- This is change directory command.
  2. /d -- This switch makes cd change both drive and directory at once. Without it you would have to do cd %~d0 & cd %~p0. (%~d0 Changs active drive, cd %~p0 change the directory).
  3. %~dp0 -- This can be dissected further into three parts:
    1. %0 -- This represents zeroth parameter of your batch script. It expands into the name of the batch file itself.
    2. %~0 -- The ~ there strips double quotes (") around the expanded argument.
    3. %dp0 -- The d and p there are modifiers of the expansion. The d forces addition of a drive letter and the p adds full path.

Getting Exception(org.apache.poi.openxml4j.exception - no content type [M1.13]) when reading xlsx file using Apache POI?

Try saving the file as Excel Workbook ONLY. NOT any other format. It worked for me. I was getting the same error.

Keras input explanation: input_shape, units, batch_size, dim, etc

Input Dimension Clarified:

Not a direct answer, but I just realized the word Input Dimension could be confusing enough, so be wary:

It (the word dimension alone) can refer to:

a) The dimension of Input Data (or stream) such as # N of sensor axes to beam the time series signal, or RGB color channel (3): suggested word=> "InputStream Dimension"

b) The total number /length of Input Features (or Input layer) (28 x 28 = 784 for the MINST color image) or 3000 in the FFT transformed Spectrum Values, or

"Input Layer / Input Feature Dimension"

c) The dimensionality (# of dimension) of the input (typically 3D as expected in Keras LSTM) or (#RowofSamples, #of Senors, #of Values..) 3 is the answer.

"N Dimensionality of Input"

d) The SPECIFIC Input Shape (eg. (30,50,50,3) in this unwrapped input image data, or (30, 250, 3) if unwrapped Keras:

Keras has its input_dim refers to the Dimension of Input Layer / Number of Input Feature

model = Sequential()
model.add(Dense(32, input_dim=784))  #or 3 in the current posted example above
model.add(Activation('relu'))

In Keras LSTM, it refers to the total Time Steps

The term has been very confusing, is correct and we live in a very confusing world!!

I find one of the challenge in Machine Learning is to deal with different languages or dialects and terminologies (like if you have 5-8 highly different versions of English, then you need to very high proficiency to converse with different speakers). Probably this is the same in programming languages too.

How to change link color (Bootstrap)

For a direct change, you can use Bootstrap classes in the <a> tag (it won't work in the <div>):

<h4 class="text-center"><a class="text-warning" href="#">Your text</a></h4>

Local dependency in package.json

If you want to further automate this, because you are checking your module into version control, and don't want to rely upon devs remembering to npm link, you can add this to your package.json "scripts" section:

"scripts": {
    "postinstall": "npm link ../somelocallib",
    "postupdate": "npm link ../somelocallib"
  }

This feels beyond hacky, but it seems to "work". Got the tip from this npm issue: https://github.com/npm/npm/issues/1558#issuecomment-12444454

Warning about `$HTTP_RAW_POST_DATA` being deprecated

Been awhile until I came across this error. Put up my answer for anyone who may stumble upon this issue.

The error only means that you are sending an empty POST request. This error is commonly found on HTTPRequests with no parameters passed. To avoid this error, you can always add a parameter to the POST without changing the php.ini.

Like:

$.post(URL_HERE
    ,{addedvar : 'anycontent'}
    ,function(d){
       doAnyHere(d);
    }
    ,'json' //or 'html','text'
);

force client disconnect from server with socket.io and nodejs

Socket.io uses the EventEmitter pattern to disconnect/connect/check heartbeats so you could do. Client.emit('disconnect');

Javascript Src Path

Use an relative path to the root of your site, for example:

If clock.js is on http://domain.com/javascript/clock.js

Include :

<script language="JavaScript" src="/javascript/clock.js"></script>

If it's on your domain root directory:

<script language="JavaScript" src="/clock.js"></script>

How many bytes is unsigned long long?

The beauty of C++, like C, is that the sized of these things are implementation-defined, so there's no correct answer without your specifying the compiler you're using. Are those two the same? Yes. "long long" is a synonym for "long long int", for any compiler that will accept both.

How to install XCODE in windows 7 platform?

X-code is primarily made for OS-X or iPhone development on Mac systems. Versions for Windows are not available. However this might help!

There is no way to get Xcode on Windows; however you can use a different SDK like Corona instead although it will not use Objective-C (I believe it uses Lua). I have however heard that it is horrible to use.

Source: classroomm.com

Pass Parameter to Gulp Task

Here is my sample how I use it. For the css/less task. Can be applied for all.

var cssTask = function (options) {
  var minifyCSS = require('gulp-minify-css'),
    less = require('gulp-less'),
    src = cssDependencies;

  src.push(codePath + '**/*.less');

  var run = function () {
    var start = Date.now();

    console.log('Start building CSS/LESS bundle');

    gulp.src(src)
      .pipe(gulpif(options.devBuild, plumber({
        errorHandler: onError
      })))
      .pipe(concat('main.css'))
      .pipe(less())
      .pipe(gulpif(options.minify, minifyCSS()))
      .pipe(gulp.dest(buildPath + 'css'))
      .pipe(gulpif(options.devBuild, browserSync.reload({stream:true})))
      .pipe(notify(function () {
        console.log('END CSS/LESS built in ' + (Date.now() - start) + 'ms');
      }));
  };

  run();

  if (options.watch) {
    gulp.watch(src, run);
  }
};

gulp.task('dev', function () {
  var options = {
    devBuild: true,
    minify: false,
    watch: false
  };

  cssTask (options);
});

Convert array to JSON

One other way could be this:

        var json_arr = {};
        json_arr["name1"] = "value1";
        json_arr["name2"] = "value2";
        json_arr["name3"] = "value3";

        var json_string = JSON.stringify(json_arr);

CSS Display an Image Resized and Cropped

img {
    position: absolute;
    clip: rect(0px,60px,200px,0px);
} 

CSS: How to have position:absolute div inside a position:relative div not be cropped by an overflow:hidden on a container

A trick that works is to position box #2 with position: absolute instead of position: relative. We usually put a position: relative on an outer box (here box #2) when we want an inner box (here box #3) with position: absolute to be positioned relative to the outer box. But remember: for box #3 to be positioned relative to box #2, box #2 just need to be positioned. With this change, we get:

And here is the full code with this change:

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
        <style type="text/css">

            /* Positioning */
            #box1 { overflow: hidden }
            #box2 { position: absolute }
            #box3 { position: absolute; top: 10px }

            /* Styling */
            #box1 { background: #efe; padding: 5px; width: 125px }
            #box2 { background: #fee; padding: 2px; width: 100px; height: 100px }
            #box3 { background: #eef; padding: 2px; width: 75px; height: 150px }

        </style>
    </head>
    <body>
        <br/><br/><br/>
        <div id="box1">
            <div id="box2">
                <div id="box3"/>
            </div>
        </div>
    </body>
</html>

How to read files and stdout from a running Docker container

You can view the filesystem of the container at

/var/lib/docker/devicemapper/mnt/$CONTAINER_ID/rootfs/

and you can just

tail -f mylogfile.log

Difference between clustered and nonclustered index

faster to read than non cluster as data is physically storted in index order we can create only one per table.(cluster index)

quicker for insert and update operation than a cluster index. we can create n number of non cluster index.

Check if string contains \n Java

I'd rather trust JDK over System property. Following is a working snippet.

    private boolean checkIfStringContainsNewLineCharacters(String str){
        if(!StringUtils.isEmpty(str)){
            Scanner scanner = new Scanner(str);
            scanner.nextLine();
            boolean hasNextLine =  scanner.hasNextLine();
            scanner.close();
            return hasNextLine;
        }
        return false;
    }

VS 2017 Git Local Commit DB.lock error on every commit

if you are using an IDE like visual studio and it is open while you sending commands close IDE and try again

git add .

and other commands, it will workout

Using HTML5/JavaScript to generate and save a file

I've used FileSaver (https://github.com/eligrey/FileSaver.js) and it works just fine.
For example, I did this function to export logs displayed on a page.
You have to pass an array for the instanciation of the Blob, so I just maybe didn't write this the right way, but it works for me.
Just in case, be careful with the replace: this is the syntax to make this global, otherwise it will only replace the first one he meets.

exportLogs : function(){
    var array = new Array();

    var str = $('#logs').html();
    array[0] = str.replace(/<br>/g, '\n\t');

    var blob = new Blob(array, {type: "text/plain;charset=utf-8"});
    saveAs(blob, "example.log");
}

How to compare datetime with only date in SQL Server

If you are on SQL Server 2008 or later you can use the date datatype:

SELECT *
FROM [User] U
WHERE CAST(U.DateCreated as DATE) = '2014-02-07'

It should be noted that if date column is indexed then this will still utilise the index and is SARGable. This is a special case for dates and datetimes.

enter image description here

You can see that SQL Server actually turns this into a > and < clause:

enter image description here

I've just tried this on a large table, with a secondary index on the date column as per @kobik's comments and the index is still used, this is not the case for the examples that use BETWEEN or >= and <:

SELECT *
FROM [User] U
WHERE CAST(U.DateCreated as DATE) = '2016-07-05'

showing index usage with secondary index

How can I set a DateTimePicker control to a specific date?

Just need to set the value property in a convenient place (such as InitializeComponent()):

    dateTimePicker1.Value = DateTime.Today.AddDays(-1);

ng is not recognized as an internal or external command

Add the ng command path from the folder .bin under the node_modules to PATH variable in the system env settings.

e.g: add C:\testProject\node_modules\.bin\ to PATH

Restart your IDE.

Set default value of an integer column SQLite

A column with default value:

CREATE TABLE <TableName>(
...
<ColumnName> <Type> DEFAULT <DefaultValue>
...
)

<DefaultValue> is a placeholder for a:

  • value literal
  • ( expression )

Examples:

Count INTEGER DEFAULT 0,
LastSeen TEXT DEFAULT (datetime('now'))

PHP php_network_getaddresses: getaddrinfo failed: No such host is known

A weird thing I found was that the environment variable SYSTEMROOT must be set otherwise getaddrinfo() will fail on Windows 10.

Move div to new line

I've found that you can move div elements to the next line simply by setting the property Display: block;

On each div.

How do I open a second window from the first window in WPF?

You can create a button in window1 and double click on it. It will create a new click handler, where inside you can write something like this:

var window2 = new Window2();
window2.Show();

Is there a way to cache GitHub credentials for pushing commits?

OAuth

You can create your own personal API token (OAuth) and use it the same way as you would use your normal credentials (at: /settings/tokens). For example:

git remote add fork https://[email protected]/foo/bar
git push fork

.netrc

Another method is to configure your user/password in ~/.netrc (_netrc on Windows), e.g.

machine github.com
login USERNAME
password PASSWORD

For HTTPS, add the extra line:

protocol https

A credential helper

To cache your GitHub password in Git when using HTTPS, you can use a credential helper to tell Git to remember your GitHub username and password every time it talks to GitHub.

  • Mac: git config --global credential.helper osxkeychain (osxkeychain helper is required),
  • Windows: git config --global credential.helper wincred
  • Linux and other: git config --global credential.helper cache

Related:

Disabling Strict Standards in PHP 5.4

If you would need to disable E_DEPRACATED also, use:

php_value error_reporting 22527

In my case CMS Made Simple was complaining "E_STRICT is enabled in the error_reporting" as well as "E_DEPRECATED is enabled". Adding that one line to .htaccess solved both misconfigurations.

How can labels/legends be added for all chart types in chart.js (chartjs.org)?

For line chart, I use the following codes.

First create custom style

.boxx{
    position: relative;
    width: 20px;
    height: 20px;
    border-radius: 3px;
}

Then add this on your line options

var lineOptions = {
            legendTemplate : '<table>'
                            +'<% for (var i=0; i<datasets.length; i++) { %>'
                            +'<tr><td><div class=\"boxx\" style=\"background-color:<%=datasets[i].fillColor %>\"></div></td>'
                            +'<% if (datasets[i].label) { %><td><%= datasets[i].label %></td><% } %></tr><tr height="5"></tr>'
                            +'<% } %>'
                            +'</table>',
            multiTooltipTemplate: "<%= datasetLabel %> - <%= value %>"

var ctx = document.getElementById("lineChart").getContext("2d");
var myNewChart = new Chart(ctx).Line(lineData, lineOptions);
document.getElementById('legendDiv').innerHTML = myNewChart.generateLegend();

Don't forget to add

<div id="legendDiv"></div>

on your html where do you want to place your legend. That's it!

Where are Magento's log files located?

You can find the log within you Magento root directory under

var/log

there are two types of log files system.log and exception.log

you need to give the correct permission to var folder, then enable logging from your Magento admin by going to

System > Configuration> Developer > Log Settings > Enable = Yes

system.log is used for general debugging and catches almost all log entries from Magento, including warning, debug and errors messages from both native and custom modules.

exception.log is reserved for exceptions only, for example when you are using try-catch statement.

To output to either the default system.log or the exception.log see the following code examples:

Mage::log('My log entry');
Mage::log('My log message: '.$myVariable);
Mage::log($myArray);
Mage::log($myObject);
Mage::logException($e);

You can create your own log file for more debugging

Mage::log('My log entry', null, 'mylogfile.log');

How can I disable inherited css styles?

Give the div you don't want him inheriting the property background too.

How to make audio autoplay on chrome

Just add this small script as depicted in https://developers.google.com/web/updates/2017/09/autoplay-policy-changes#webaudio

<head>
<script>
window.onload = function() {
  var context = new AudioContext();
}
</script>
</head>

Than this will work as you want:

<audio autoplay>
      <source src="hal_9000_sorry_dave.mp3">
</audio>

When is "java.io.IOException:Connection reset by peer" thrown?

To expand on BalusC's answer, any scenario where the sender continues to write after the peer has stopped reading and closed its socket will produce this exception, as will the peer closing while it still had unread data in its own socket receive buffer. In other words, an application protocol error. For example, if you write something to the peer that the peer doesn't understand, and then it closes its socket in protest, and you then continue to write, the peer's TCP stack will issue an RST, which results in this exception and message at the sender.

Query to list number of records in each table in a database

sp_MSForEachTable 'DECLARE @t AS VARCHAR(MAX); 
SELECT @t = CAST(COUNT(1) as VARCHAR(MAX)) 
+ CHAR(9) + CHAR(9) + ''?'' FROM ? ; PRINT @t'

Output:

enter image description here

using BETWEEN in WHERE condition

I think we can write like this : $this->db->where('accommodation >=', minvalue); $this->db->where('accommodation <=', maxvalue);

//without dollar($) sign It's work for me :)

How do I execute a program using Maven?

With the global configuration that you have defined for the exec-maven-plugin:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.4.0</version>
  <configuration>
    <mainClass>org.dhappy.test.NeoTraverse</mainClass>
  </configuration>
</plugin>

invoking mvn exec:java on the command line will invoke the plugin which is configured to execute the class org.dhappy.test.NeoTraverse.

So, to trigger the plugin from the command line, just run:

mvn exec:java

Now, if you want to execute the exec:java goal as part of your standard build, you'll need to bind the goal to a particular phase of the default lifecycle. To do this, declare the phase to which you want to bind the goal in the execution element:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>exec-maven-plugin</artifactId>
  <version>1.4</version>
  <executions>
    <execution>
      <id>my-execution</id>
      <phase>package</phase>
      <goals>
        <goal>java</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <mainClass>org.dhappy.test.NeoTraverse</mainClass>
  </configuration>
</plugin>

With this example, your class would be executed during the package phase. This is just an example, adapt it to suit your needs. Works also with plugin version 1.1.

Sort a two dimensional array based on one column

class ArrayComparator implements Comparator<Comparable[]> {
    private final int columnToSort;
    private final boolean ascending;

    public ArrayComparator(int columnToSort, boolean ascending) {
        this.columnToSort = columnToSort;
        this.ascending = ascending;
    }

    public int compare(Comparable[] c1, Comparable[] c2) {
        int cmp = c1[columnToSort].compareTo(c2[columnToSort]);
        return ascending ? cmp : -cmp;
    }
}

This way you can handle any type of data in those arrays (as long as they're Comparable) and you can sort any column in ascending or descending order.

String[][] data = getData();
Arrays.sort(data, new ArrayComparator(0, true));

PS: make sure you check for ArrayIndexOutOfBounds and others.

EDIT: The above solution would only be helpful if you are able to actually store a java.util.Date in the first column or if your date format allows you to use plain String comparison for those values. Otherwise, you need to convert that String to a Date, and you can achieve that using a callback interface (as a general solution). Here's an enhanced version:

class ArrayComparator implements Comparator<Object[]> {
    private static Converter DEFAULT_CONVERTER = new Converter() {
        @Override
        public Comparable convert(Object o) {
            // simply assume the object is Comparable
            return (Comparable) o;
        }
    };
    private final int columnToSort;
    private final boolean ascending;
    private final Converter converter;


    public ArrayComparator(int columnToSort, boolean ascending) {
        this(columnToSort, ascending, DEFAULT_CONVERTER);
    }

    public ArrayComparator(int columnToSort, boolean ascending, Converter converter) {
        this.columnToSort = columnToSort;
        this.ascending = ascending;
        this.converter = converter;
    }

    public int compare(Object[] o1, Object[] o2) {
        Comparable c1 = converter.convert(o1[columnToSort]);
        Comparable c2 = converter.convert(o2[columnToSort]);
        int cmp = c1.compareTo(c2);
        return ascending ? cmp : -cmp;
    }

}

interface Converter {
    Comparable convert(Object o);
}

class DateConverter implements Converter {
    private static final DateFormat df = new SimpleDateFormat("yyyy.MM.dd hh:mm");

    @Override
    public Comparable convert(Object o) {
        try {
            return df.parse(o.toString());
        } catch (ParseException e) {
            throw new IllegalArgumentException(e);
        }
    }
}

And at this point, you can sort on your first column with:

Arrays.sort(data, new ArrayComparator(0, true, new DateConverter());

I skipped the checks for nulls and other error handling issues.

I agree this is starting to look like a framework already. :)

Last (hopefully) edit: I only now realize that your date format allows you to use plain String comparison. If that is the case, you don't need the "enhanced version".

SQL "select where not in subquery" returns no results

SELECT T.common_id
  FROM Common T
       LEFT JOIN Table1 T1 ON T.common_id = T1.common_id
       LEFT JOIN Table2 T2 ON T.common_id = T2.common_id
 WHERE T1.common_id IS NULL
   AND T2.common_id IS NULL

Regular expression to extract numbers from a string

^\s*(\w+)\s*\(\s*(\d+)\D+(\d+)\D+\)\s*$

should work. After the match, backreference 1 will contain the month, backreference 2 will contain the first number and backreference 3 the second number.

Explanation:

^     # start of string
\s*   # optional whitespace
(\w+) # one or more alphanumeric characters, capture the match
\s*   # optional whitespace
\(    # a (
\s*   # optional whitespace
(\d+) # a number, capture the match
\D+   # one or more non-digits
(\d+) # a number, capture the match
\D+   # one or more non-digits
\)    # a )
\s*   # optional whitespace
$     # end of string

Join two sql queries

Try this:

select Activity, SUM(Incomes.Amount) as "Total Amount 2009", SUM(Incomes2008.Amount) 
as "Total Amount 2008" from
Activities, Incomes, Incomes2008
where Activities.UnitName = ?  AND
Incomes.ActivityId = Activities.ActivityID  AND
Incomes2008.ActivityId = Activities.ActivityID GROUP BY
Activity ORDER BY Activity;

Basically you have to JOIN Incomes2008 table with the output of your first query.

How to add parameters to an external data query in Excel which can't be displayed graphically?

Excel's interface for SQL Server queries will not let you have a custom parameters.  A way around this is to create a generic Microsoft Query, then add parameters, then paste your parametorized query in the connection's properties.  Here are the detailed steps for Excel 2010:

  1. Open Excel
  2. Goto Data tab
  3. From the From Other Sources button choose From Microsoft Query
  4. The "Choose Data Source" window will appear.  Choose a datasource and click OK.
  5. The Query Qizard
    1. Choose Column: window will appear.  The goal is to create a generic query. I recommend choosing one column from a small table.
    2. Filter Data: Just click Next
    3. Sort Order: Just click Next
    4. Finish: Just click Finish.
  6. The "Import Data" window will appear:
    1. Click the Properties... button.
      1. Choose the Definition tab
      2. In the "Command text:" section add a WHERE clause that includes Excel parameters.  It's important to add all the parameters that you want now.  For example, if I want two parameters I could add this:
        WHERE 1 = ? and 2 = ?
      3. Click OK to get back to the "Import Data" window
    2. Choose PivotTable Report
    3. Click OK
  7. You will be prompted to enter the parameters value for each parameter.
  8. Once you have enter the parameters you will be at your pivot table
  9. Go batck to the Data tab and click the connections Properties button
    1. Click the Definition tab
    2. In the "Command text:" section, Paste in the real SQL Query that you want with the same number of parameters that you defined earlier.
    3. Click the Parameters... button 
      1. enter the Prompt values for each parameter
      2. Click OK
    4. Click OK to close the properties window
  10. Congratulations, you now have parameters.

java, get set methods

your panel class don't have a constructor that accepts a string

try change

RLS_strid_panel p = new RLS_strid_panel(namn1);

to

RLS_strid_panel p = new RLS_strid_panel();
p.setName1(name1);

align divs to the bottom of their container

You can cheat! Say your div is 20px high, place the div at the top of the next container and set

position: absolute;
top: -20px;

It may not be semantically clean but does scale with responsive designs

response.sendRedirect() from Servlet to JSP does not seem to work

I'm posting this answer because the one with the most votes led me astray. To redirect from a servlet, you simply do this:

response.sendRedirect("simpleList.do")

In this particular question, I think @M-D is correctly explaining why the asker is having his problem, but since this is the first result on google when you search for "Redirect from Servlet" I think it's important to have an answer that helps most people, not just the original asker.

SoapFault exception: Could not connect to host

In my case, disabled SELINUX allow PHP to call my WebService. I run PHP in FPM with Apache2

SELinux status :

# sestatus

Disable SELinux :

setenforce 0

Enable SELinux :

# setenforce 1

Permanent disable :

edit this file /etc/selinux/config

How to get the command line args passed to a running process on unix/linux systems?

Another variant of printing /proc/PID/cmdline with spaces in Linux is:

cat -v /proc/PID/cmdline | sed 's/\^@/\ /g' && echo

In this way cat prints NULL characters as ^@ and then you replace them with a space using sed; echo prints a newline.

How to generate Javadoc HTML files in Eclipse?

This is a supplement answer related to the OP:

An easy and reliable solution to add Javadocs comments in Eclipse:

  1. Go to Help > Eclipse Marketplace....
  2. Find "JAutodoc".
  3. Install it and restart Eclipse.

To use this tool, right-click on class and click on JAutodoc.

count number of characters in nvarchar column

Use the LEN function:

Returns the number of characters of the specified string expression, excluding trailing blanks.

Working copy locked error in tortoise svn while committing

I managed to lock myself out of a file in svn - don't know how - but when I tried (re)-getting the lock (Tortoise was showing the "Get Lock" option for the file), it complained that already had the lock. I tried deleting the file and committing the directory change - same result. I tried CleanUp (including refreshing the overlay), but that failed too.

The solution was to go into the Tortoise repo-browser, find the file and use the break lock function.

How does HTTP_USER_AGENT work?

http://www.useragentstring.com/

Visit that page, it'll give you a good explanation of each element of your user agent.

Mozilla:

MozillaProductSlice. Claims to be a Mozilla based user agent, which is only true for Gecko browsers like Firefox and Netscape. For all other user agents it means 'Mozilla-compatible'. In modern browsers, this is only used for historical reasons. It has no real meaning anymore

Git: Pull from other remote

upstream in the github example is just the name they've chosen to refer to that repository. You may choose any that you like when using git remote add. Depending on what you select for this name, your git pull usage will change. For example, if you use:

git remote add upstream git://github.com/somename/original-project.git

then you would use this to pull changes:

git pull upstream master

But, if you choose origin for the name of the remote repo, your commands would be:

To name the remote repo in your local config: git remote add origin git://github.com/somename/original-project.git

And to pull: git pull origin master

How does one use glide to download an image into a bitmap?

Make sure you are on the Lastest version

implementation 'com.github.bumptech.glide:glide:4.10.0'

Kotlin:

Glide.with(this)
        .asBitmap()
        .load(imagePath)
        .into(object : CustomTarget<Bitmap>(){
            override fun onResourceReady(resource: Bitmap, transition: Transition<in Bitmap>?) {
                imageView.setImageBitmap(resource)
            }
            override fun onLoadCleared(placeholder: Drawable?) {
                // this is called when imageView is cleared on lifecycle call or for
                // some other reason.
                // if you are referencing the bitmap somewhere else too other than this imageView
                // clear it here as you can no longer have the bitmap
            }
        })

Bitmap Size:

if you want to use the original size of the image use the default constructor as above, else You can pass your desired size for bitmap

into(object : CustomTarget<Bitmap>(1980, 1080)

Java:

Glide.with(this)
        .asBitmap()
        .load(path)
        .into(new CustomTarget<Bitmap>() {
            @Override
            public void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {
                imageView.setImageBitmap(resource);
            }

            @Override
            public void onLoadCleared(@Nullable Drawable placeholder) {
            }
        });

Old Answer:

With compile 'com.github.bumptech.glide:glide:4.8.0' and below

Glide.with(this)
        .asBitmap()
        .load(path)
        .into(new SimpleTarget<Bitmap>() {
            @Override
            public void onResourceReady(Bitmap resource, Transition<? super Bitmap> transition) {
                imageView.setImageBitmap(resource);
            }
        });

For compile 'com.github.bumptech.glide:glide:3.7.0' and below

Glide.with(this)
        .load(path)
        .asBitmap()
        .into(new SimpleTarget<Bitmap>() {
            @Override
            public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
                imageView.setImageBitmap(resource);
            }
        });

Now you might see a warning SimpleTarget is deprecated

Reason:

The main point of deprecating SimpleTarget is to warn you about the ways in which it tempts you to break Glide's API contract. Specifically, it doesn't do anything to force you to stop using any resource you've loaded once the SimpleTarget is cleared, which can lead to crashes and graphical corruption.

The SimpleTarget still can be used as long you make sure you are not using the bitmap once the imageView is cleared.

Java2D: Increase the line width

What is Stroke:

The BasicStroke class defines a basic set of rendering attributes for the outlines of graphics primitives, which are rendered with a Graphics2D object that has its Stroke attribute set to this BasicStroke.

https://docs.oracle.com/javase/7/docs/api/java/awt/BasicStroke.html

Note that the Stroke setting:

Graphics2D g2 = (Graphics2D) g;
g2.setStroke(new BasicStroke(10));

is setting the line width,since BasicStroke(float width):

Constructs a solid BasicStroke with the specified line width and with default values for the cap and join styles.

And, it also effects other methods like Graphics2D.drawLine(int x1, int y1, int x2, int y2) and Graphics2D.drawRect(int x, int y, int width, int height):

The methods of the Graphics2D interface that use the outline Shape returned by a Stroke object include draw and any other methods that are implemented in terms of that method, such as drawLine, drawRect, drawRoundRect, drawOval, drawArc, drawPolyline, and drawPolygon.

How to get a reversed list view on a list in Java?

If i have understood correct then it is one line of code .It worked for me .

 Collections.reverse(yourList);

A weighted version of random.choice

A general solution:

import random
def weighted_choice(choices, weights):
    total = sum(weights)
    treshold = random.uniform(0, total)
    for k, weight in enumerate(weights):
        total -= weight
        if total < treshold:
            return choices[k]

Using iFrames In ASP.NET

try this

<iframe name="myIframe" id="myIframe" width="400px" height="400px" runat="server"></iframe>

Expose this iframe in the master page's codebehind:

public HtmlControl iframe
{
get
{
return this.myIframe;
}
}

Add the MasterType directive for the content page to strongly typed Master Page.

<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits=_Default" Title="Untitled Page" %>
<%@ MasterType VirtualPath="~/MasterPage.master" %>

In code behind

protected void Page_Load(object sender, EventArgs e)
{
this.Master.iframe.Attributes.Add("src", "some.aspx");
}

Win32Exception (0x80004005): The wait operation timed out

If you're using Entity Framework, you can extend the default timeout (to give a long-running query more time to complete) by doing:

myDbContext.Database.CommandTimeout = 300;

Where myDbContext is your DbContext instance, and 300 is the timeout value in seconds.

(Syntax current as of Entity Framework 6.)

Xampp MySQL not starting - "Attempting to start MySQL service..."

After Stop xampp, go to configure and change the port 3306 to 3308 of mysql and save. Now start the sql......Enjoy

SQL Server Insert if not exists

You could use the GO command. That will restart the execution of SQL statements after an error. In my case I have a few 1000 INSERT statements, where a handful of those records already exist in the database, I just don't know which ones. I found that after processing a few 100, execution just stops with an error message that it can't INSERT as the record already exists. Quite annoying, but putting a GO solved this. It may not be the fastest solution, but speed was not my problem.

GO
INSERT INTO mytable (C1,C2,C3) VALUES(1,2,3)
GO
INSERT INTO mytable (C1,C2,C3) VALUES(4,5,6)
 etc ...

How to kill all active and inactive oracle sessions for user

For Oracle 11g this may not work as you may receive an error like below

Error report:
SQL Error: ORA-00026: missing or invalid session ID
00026. 00000 -  "missing or invalid session ID"
*Cause:    Missing or invalid session ID string for ALTER SYSTEM KILL SESSION.
*Action:   Retry with a valid session ID.

To rectify this, use below code to identify the sessions

SQL> select inst_id,sid,serial# from gv$session or v$session

NOTE : v$session do not have inst_id field

and Kill them using

alter system kill session 'sid,serial,@inst_id' IMMEDIATE;

pip install - locale.Error: unsupported locale setting

Run the following command (it will work):

export LC_ALL="en_US.UTF-8"
export LC_CTYPE="en_US.UTF-8"
sudo dpkg-reconfigure locales

How to change working directory in Jupyter Notebook?

It's simple, every time you open Jupyter Notebook and you are in your current work directory, open the Terminal in the near top right corner position where create new Python file in. The terminal in Jupyter will appear in the new tab. Type command cd <your new work directory> and enter, and then type Jupyter Notebook in that terminal, a new Jupyter Notebook will appear in the new tab with your new work directory.

What is the difference between display: inline and display: inline-block?

All answers above contribute important info on the original question. However, there is a generalization that seems wrong.

It is possible to set width and height to at least one inline element (that I can think of) – the <img> element.

Both accepted answers here and on this duplicate state that this is not possible but this doesn’t seem like a valid general rule.

Example:

_x000D_
_x000D_
img {_x000D_
  width: 200px;_x000D_
  height: 200px;_x000D_
  border: 1px solid red;_x000D_
}
_x000D_
<img src="#" />
_x000D_
_x000D_
_x000D_

The img has display: inline, but its width and height were successfully set.

Python element-wise tuple operations like sum

even simpler and without using map, you can do that

>>> tuple(sum(i) for i in zip((1, 2, 3), (3, 2, 1)))
(4, 4, 4)

Looping through array and removing items, without breaking for loop

Here is another example for the proper use of splice. This example is about to remove 'attribute' from 'array'.

for (var i = array.length; i--;) {
    if (array[i] === 'attribute') {
        array.splice(i, 1);
    }
}

What is the use of BindingResult interface in spring MVC?

From the official Spring documentation:

General interface that represents binding results. Extends the interface for error registration capabilities, allowing for a Validator to be applied, and adds binding-specific analysis and model building.

Serves as result holder for a DataBinder, obtained via the DataBinder.getBindingResult() method. BindingResult implementations can also be used directly, for example to invoke a Validator on it (e.g. as part of a unit test).

Round to 5 (or other number) in Python

Use:

>>> def round_to_nearest(n, m):
        r = n % m
        return n + m - r if r + r >= m else n - r

It does not use multiplication and will not convert from/to floats.

Rounding to the nearest multiple of 10:

>>> for n in range(-21, 30, 3): print('{:3d}  =>  {:3d}'.format(n, round_to_nearest(n, 10)))
-21  =>  -20
-18  =>  -20
-15  =>  -10
-12  =>  -10
 -9  =>  -10
 -6  =>  -10
 -3  =>    0
  0  =>    0
  3  =>    0
  6  =>   10
  9  =>   10
 12  =>   10
 15  =>   20
 18  =>   20
 21  =>   20
 24  =>   20
 27  =>   30

As you can see, it works for both negative and positive numbers. Ties (e.g. -15 and 15) will always be rounded upwards.

A similar example that rounds to the nearest multiple of 5, demonstrating that it also behaves as expected for a different "base":

>>> for n in range(-21, 30, 3): print('{:3d}  =>  {:3d}'.format(n, round_to_nearest(n, 5)))
-21  =>  -20
-18  =>  -20
-15  =>  -15
-12  =>  -10
 -9  =>  -10
 -6  =>   -5
 -3  =>   -5
  0  =>    0
  3  =>    5
  6  =>    5
  9  =>   10
 12  =>   10
 15  =>   15
 18  =>   20
 21  =>   20
 24  =>   25
 27  =>   25

Join vs. sub-query

Sub-queries are the logically correct way to solve problems of the form, "Get facts from A, conditional on facts from B". In such instances, it makes more logical sense to stick B in a sub-query than to do a join. It is also safer, in a practical sense, since you don't have to be cautious about getting duplicated facts from A due to multiple matches against B.

Practically speaking, however, the answer usually comes down to performance. Some optimisers suck lemons when given a join vs a sub-query, and some suck lemons the other way, and this is optimiser-specific, DBMS-version-specific and query-specific.

Historically, explicit joins usually win, hence the established wisdom that joins are better, but optimisers are getting better all the time, and so I prefer to write queries first in a logically coherent way, and then restructure if performance constraints warrant this.

How to redirect Valgrind's output to a file?

By default, Valgrind writes its output to stderr. So you need to do something like:

valgrind a.out > log.txt 2>&1

Alternatively, you can tell Valgrind to write somewhere else; see http://valgrind.org/docs/manual/manual-core.html#manual-core.comment (but I've never tried this).

How to get a Static property with Reflection

A little clarity...

// Get a PropertyInfo of specific property type(T).GetProperty(....)
PropertyInfo propertyInfo;
propertyInfo = typeof(TypeWithTheStaticProperty)
    .GetProperty("NameOfStaticProperty", BindingFlags.Public | BindingFlags.Static); 

// Use the PropertyInfo to retrieve the value from the type by not passing in an instance
object value = propertyInfo.GetValue(null, null);

// Cast the value to the desired type
ExpectedType typedValue = (ExpectedType) value;

Assign null to a SqlParameter

You need pass DBNull.Value as a null parameter within SQLCommand, unless a default value is specified within stored procedure (if you are using stored procedure). The best approach is to assign DBNull.Value for any missing parameter before query execution, and following foreach will do the job.

foreach (SqlParameter parameter in sqlCmd.Parameters)
{
    if (parameter.Value == null)
    {
        parameter.Value = DBNull.Value;
    }
}

Otherwise change this line:

planIndexParameter.Value = (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex;

As follows:

if (AgeItem.AgeIndex== null)
    planIndexParameter.Value = DBNull.Value;
else
    planIndexParameter.Value = AgeItem.AgeIndex;

Because you can't use different type of values in conditional statement, as DBNull and int are different from each other. Hope this will help.

MySQL pivot table query with dynamic columns

The only way in MySQL to do this dynamically is with Prepared statements. Here is a good article about them:

Dynamic pivot tables (transform rows to columns)

Your code would look like this:

SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'MAX(IF(pa.fieldname = ''',
      fieldname,
      ''', pa.fieldvalue, NULL)) AS ',
      fieldname
    )
  ) INTO @sql
FROM product_additional;

SET @sql = CONCAT('SELECT p.id
                    , p.name
                    , p.description, ', @sql, ' 
                   FROM product p
                   LEFT JOIN product_additional AS pa 
                    ON p.id = pa.id
                   GROUP BY p.id');

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

See Demo

NOTE: GROUP_CONCAT function has a limit of 1024 characters. See parameter group_concat_max_len

Moment js get first and last day of current month

I ran into some issues because I wasn't aware that moment().endOf() mutates the input date, so I used this work around.

_x000D_
_x000D_
let thisMoment = moment();
let endOfMonth = moment(thisMoment).endOf('month');
let startOfMonth = moment(thisMoment).startOf('month');
_x000D_
_x000D_
_x000D_

Loop through a date range with JavaScript

Based on Jayarjo's answer:

var loopDate = new Date();
loopDate.setTime(datFrom.valueOf());

while (loopDate.valueOf() < datTo.valueOf() + 86400000) {

    alert(loopDay);

    loopDate.setTime(loopDate.valueOf() + 86400000);
}

How to delete Project from Google Developers Console

Simply go to https://console.developers.google.com/iam-admin/projects you must be signed in of course. There you will see the all your projects google console projects so just select the project you want to delete, and click delete project option which is shown at the top of the table. I have provided the screenshothere

How can I split a shell command over multiple lines when using an IF statement?

The line-continuation will fail if you have whitespace (spaces or tab characters[1]) after the backslash and before the newline. With no such whitespace, your example works fine for me:

$ cat test.sh
if ! fab --fabfile=.deploy/fabfile.py \
   --forward-agent \
   --disable-known-hosts deploy:$target; then
     echo failed
else
     echo succeeded
fi

$ alias fab=true; . ./test.sh
succeeded
$ alias fab=false; . ./test.sh
failed

Some detail promoted from the comments: the line-continuation backslash in the shell is not really a special case; it is simply an instance of the general rule that a backslash "quotes" the immediately-following character, preventing any special treatment it would normally be subject to. In this case, the next character is a newline, and the special treatment being prevented is terminating the command. Normally, a quoted character winds up included literally in the command; a backslashed newline is instead deleted entirely. But otherwise, the mechanism is the same. Most importantly, the backslash only quotes the immediately-following character; if that character is a space or tab, you just get a literal space or tab, and any subsequent newline remains unquoted.

[1] or carriage returns, for that matter, as Czechnology points out. Bash does not get along with Windows-formatted text files, not even in WSL. Or Cygwin, but at least their Bash port has added a set -o igncr option that you can set to make it carriage-return-tolerant.

Connect to SQL Server database from Node.js

This is mainly for future readers. As the question (at least the title) focuses on "connecting to sql server database from node js", I would like to chip in about "mssql" node module.

At this moment, we have a stable version of Microsoft SQL Server driver for NodeJs ("msnodesql") available here: https://www.npmjs.com/package/msnodesql. While it does a great job of native integration to Microsoft SQL Server database (than any other node module), there are couple of things to note about.

"msnodesql" require a few pre-requisites (like python, VC++, SQL native client etc.) to be installed on the host machine. That makes your "node" app "Windows" dependent. If you are fine with "Windows" based deployment, working with "msnodesql" is the best.

On the other hand, there is another module called "mssql" (available here https://www.npmjs.com/package/mssql) which can work with "tedious" or "msnodesql" based on configuration. While this module may not be as comprehensive as "msnodesql", it pretty much solves most of the needs.

If you would like to start with "mssql", I came across a simple and straight forward video, which explains about connecting to Microsoft SQL Server database using NodeJs here: https://www.youtube.com/watch?v=MLcXfRH1YzE

Source code for the above video is available here: http://techcbt.com/Post/341/Node-js-basic-programming-tutorials-videos/how-to-connect-to-microsoft-sql-server-using-node-js

Just in case, if the above links are not working, I am including the source code here:

_x000D_
_x000D_
var sql = require("mssql");_x000D_
_x000D_
var dbConfig = {_x000D_
    server: "localhost\\SQL2K14",_x000D_
    database: "SampleDb",_x000D_
    user: "sa",_x000D_
    password: "sql2014",_x000D_
    port: 1433_x000D_
};_x000D_
_x000D_
function getEmp() {_x000D_
    var conn = new sql.Connection(dbConfig);_x000D_
    _x000D_
    conn.connect().then(function () {_x000D_
        var req = new sql.Request(conn);_x000D_
        req.query("SELECT * FROM emp").then(function (recordset) {_x000D_
            console.log(recordset);_x000D_
            conn.close();_x000D_
        })_x000D_
        .catch(function (err) {_x000D_
            console.log(err);_x000D_
            conn.close();_x000D_
        });        _x000D_
    })_x000D_
    .catch(function (err) {_x000D_
        console.log(err);_x000D_
    });_x000D_
_x000D_
    //--> another way_x000D_
    //var req = new sql.Request(conn);_x000D_
    //conn.connect(function (err) {_x000D_
    //    if (err) {_x000D_
    //        console.log(err);_x000D_
    //        return;_x000D_
    //    }_x000D_
    //    req.query("SELECT * FROM emp", function (err, recordset) {_x000D_
    //        if (err) {_x000D_
    //            console.log(err);_x000D_
    //        }_x000D_
    //        else { _x000D_
    //            console.log(recordset);_x000D_
    //        }_x000D_
    //        conn.close();_x000D_
    //    });_x000D_
    //});_x000D_
_x000D_
}_x000D_
_x000D_
getEmp();
_x000D_
_x000D_
_x000D_

The above code is pretty self explanatory. We define the db connection parameters (in "dbConfig" JS object) and then use "Connection" object to connect to SQL Server. In order to execute a "SELECT" statement, in this case, it uses "Request" object which internally works with "Connection" object. The code explains both flavors of using "promise" and "callback" based executions.

The above source code explains only about connecting to sql server database and executing a SELECT query. You can easily take it to the next level by following documentation of "mssql" node available at: https://www.npmjs.com/package/mssql

UPDATE: There is a new video which does CRUD operations using pure Node.js REST standard (with Microsoft SQL Server) here: https://www.youtube.com/watch?v=xT2AvjQ7q9E. It is a fantastic video which explains everything from scratch (it has got heck a lot of code and it will not be that pleasing to explain/copy the entire code here)

How to convert numbers to words without using num2word library?


    number=input("number")
    numls20={"1":"one","2":"two","3":"three","4":"four","5":"five","6":"six","7":"seven","8":"eight","9":"nine","10":"ten","11":"elevn","12":"twelve","13":"thirteen","14":"fourteen","15":"fifteen","16":"sixteen","17":"seventeen","18":"eighteen","19":"ninteen"}
    numls100={"1":"ten","2":"twenty","3":"thrity","4":"fourty","5":"fifty","6":"sixty","7":"seventy","8":"eighty","9":"ninty"}
    numls1000={"1":"hundred","2":"twohundred","3":"threehundred","4":"fourhundred","5":"fivehundred","6":"sixhundred","7":"sevenhundred","8":"eighthundred","9":"ninehundred"}    
    def num2str(number):
        if (int(number)<20):
            print(numls20[number])
        elif(int(number)<100):
            print(numls100[number[0]]+" "+numls20[number[1]])
        elif(int(number)<1000):
            if ((int(number))%100 == 0):
                print(numls1000[number[0]])
            else:
                print(numls1000[number[0]]+" and "+numls100[number[1]]+" "+numls20[number[2]])
        elif(int(number)<10000):
            if ((int(number))%1000 == 0):
                print(numls20[number[0]]+" thousand")
            elif(int(number)%100 == 0):
                print(numls20[number[0]]+" thousand "+numls1000[number[1]])
            elif(int(number)%10 == 0):
                print(numls20[number[0]]+" thousand "+numls1000[number[1]]+" and "+numls100[number[2]])
            else:
                print(numls20[number[0]]+" thousand "+numls1000[number[1]]+" and "+numls100[number[2]]+" "+numls20[number[3]])
    num2str(number)

Best way to randomize an array with .NET

You don't need complicated algorithms.

Just one simple line:

Random random = new Random();
array.ToList().Sort((x, y) => random.Next(-1, 1)).ToArray();

Note that we need to convert the Array to a List first, if you don't use List in the first place.

Also, mind that this is not efficient for very large arrays! Otherwise it's clean & simple.

How to replace part of string by position?

Use String.Substring() (details here) to cut left part, then your replacement, then right part. Play with indexes until you get it right :)

Something like:

string replacement=original.Substring(0,start)+
    rep+original.Substring(start+rep.Length);

How to use hex color values

RGBA Version Swift 3/4

I like @Luca's answer as i think it's the most elegant.

However I don't want my colours specified in ARGB. I'd rather RGBA + also i needed to hack in the case of dealing with strings that specify 1 character for each of the channels "#FFFA".

This version also adds error throwing + strips the '#' character if it's included in the string. Here is my modified form for Swift.

public enum ColourParsingError: Error
{
    
    case invalidInput(String)
}
extension UIColor {
    public convenience init(hexString: String) throws
    {
        let hexString = hexString.replacingOccurrences(of: "#", with: "")
        let hex = hexString.trimmingCharacters(in:NSCharacterSet.alphanumerics.inverted)
        var int = UInt32()
        Scanner(string: hex).scanHexInt32(&int)
        let a, r, g, b: UInt32
        switch hex.count 
        {
        case 3: // RGB (12-bit)
            (r, g, b,a) = ((int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17,255)
        //iCSS specification in the form of #F0FA
        case 4: // RGB (24-bit)
            (r, g, b,a) = ((int >> 12) * 17, (int >> 8 & 0xF) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
        case 6: // RGB (24-bit)
            (r, g, b, a) = (int >> 16, int >> 8 & 0xFF, int & 0xFF,255)
        case 8: // ARGB (32-bit)
            (r, g, b, a) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
        default:
            throw ColourParsingError.invalidInput("String is not a valid hex colour string: \(hexString)")
        }
        self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255)
    }
}

Resizing an image in an HTML5 canvas

So what do you do if all the browsers (actually, Chrome 5 gave me quite good one) won't give you good enough resampling quality? You implement them yourself then! Oh come on, we're entering the new age of Web 3.0, HTML5 compliant browsers, super optimized JIT javascript compilers, multi-core(†) machines, with tons of memory, what are you afraid of? Hey, there's the word java in javascript, so that should guarantee the performance, right? Behold, the thumbnail generating code:

// returns a function that calculates lanczos weight
function lanczosCreate(lobes) {
    return function(x) {
        if (x > lobes)
            return 0;
        x *= Math.PI;
        if (Math.abs(x) < 1e-16)
            return 1;
        var xx = x / lobes;
        return Math.sin(x) * Math.sin(xx) / x / xx;
    };
}

// elem: canvas element, img: image element, sx: scaled width, lobes: kernel radius
function thumbnailer(elem, img, sx, lobes) {
    this.canvas = elem;
    elem.width = img.width;
    elem.height = img.height;
    elem.style.display = "none";
    this.ctx = elem.getContext("2d");
    this.ctx.drawImage(img, 0, 0);
    this.img = img;
    this.src = this.ctx.getImageData(0, 0, img.width, img.height);
    this.dest = {
        width : sx,
        height : Math.round(img.height * sx / img.width),
    };
    this.dest.data = new Array(this.dest.width * this.dest.height * 3);
    this.lanczos = lanczosCreate(lobes);
    this.ratio = img.width / sx;
    this.rcp_ratio = 2 / this.ratio;
    this.range2 = Math.ceil(this.ratio * lobes / 2);
    this.cacheLanc = {};
    this.center = {};
    this.icenter = {};
    setTimeout(this.process1, 0, this, 0);
}

thumbnailer.prototype.process1 = function(self, u) {
    self.center.x = (u + 0.5) * self.ratio;
    self.icenter.x = Math.floor(self.center.x);
    for (var v = 0; v < self.dest.height; v++) {
        self.center.y = (v + 0.5) * self.ratio;
        self.icenter.y = Math.floor(self.center.y);
        var a, r, g, b;
        a = r = g = b = 0;
        for (var i = self.icenter.x - self.range2; i <= self.icenter.x + self.range2; i++) {
            if (i < 0 || i >= self.src.width)
                continue;
            var f_x = Math.floor(1000 * Math.abs(i - self.center.x));
            if (!self.cacheLanc[f_x])
                self.cacheLanc[f_x] = {};
            for (var j = self.icenter.y - self.range2; j <= self.icenter.y + self.range2; j++) {
                if (j < 0 || j >= self.src.height)
                    continue;
                var f_y = Math.floor(1000 * Math.abs(j - self.center.y));
                if (self.cacheLanc[f_x][f_y] == undefined)
                    self.cacheLanc[f_x][f_y] = self.lanczos(Math.sqrt(Math.pow(f_x * self.rcp_ratio, 2)
                            + Math.pow(f_y * self.rcp_ratio, 2)) / 1000);
                weight = self.cacheLanc[f_x][f_y];
                if (weight > 0) {
                    var idx = (j * self.src.width + i) * 4;
                    a += weight;
                    r += weight * self.src.data[idx];
                    g += weight * self.src.data[idx + 1];
                    b += weight * self.src.data[idx + 2];
                }
            }
        }
        var idx = (v * self.dest.width + u) * 3;
        self.dest.data[idx] = r / a;
        self.dest.data[idx + 1] = g / a;
        self.dest.data[idx + 2] = b / a;
    }

    if (++u < self.dest.width)
        setTimeout(self.process1, 0, self, u);
    else
        setTimeout(self.process2, 0, self);
};
thumbnailer.prototype.process2 = function(self) {
    self.canvas.width = self.dest.width;
    self.canvas.height = self.dest.height;
    self.ctx.drawImage(self.img, 0, 0, self.dest.width, self.dest.height);
    self.src = self.ctx.getImageData(0, 0, self.dest.width, self.dest.height);
    var idx, idx2;
    for (var i = 0; i < self.dest.width; i++) {
        for (var j = 0; j < self.dest.height; j++) {
            idx = (j * self.dest.width + i) * 3;
            idx2 = (j * self.dest.width + i) * 4;
            self.src.data[idx2] = self.dest.data[idx];
            self.src.data[idx2 + 1] = self.dest.data[idx + 1];
            self.src.data[idx2 + 2] = self.dest.data[idx + 2];
        }
    }
    self.ctx.putImageData(self.src, 0, 0);
    self.canvas.style.display = "block";
};

...with which you can produce results like these!

img717.imageshack.us/img717/8910/lanczos358.png

so anyway, here is a 'fixed' version of your example:

img.onload = function() {
    var canvas = document.createElement("canvas");
    new thumbnailer(canvas, img, 188, 3); //this produces lanczos3
    // but feel free to raise it up to 8. Your client will appreciate
    // that the program makes full use of his machine.
    document.body.appendChild(canvas);
};

Now it's time to pit your best browsers out there and see which one will least likely increase your client's blood pressure!

Umm, where's my sarcasm tag?

(since many parts of the code is based on Anrieff Gallery Generator is it also covered under GPL2? I don't know)

actually due to limitation of javascript, multi-core is not supported.

Check cell for a specific letter or set of letters

Just use = IF(A1="Bla*","YES","NO"). When you insert the asterisk, it acts as a wild card for any amount of characters after the specified text.

Set NOW() as Default Value for datetime datatype?

As of MySQL 5.6.5, you can use the DATETIME type with a dynamic default value:

CREATE TABLE foo (
    creation_time      DATETIME DEFAULT   CURRENT_TIMESTAMP,
    modification_time  DATETIME ON UPDATE CURRENT_TIMESTAMP
)

Or even combine both rules:

modification_time DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

Reference:
http://dev.mysql.com/doc/refman/5.7/en/timestamp-initialization.html
http://optimize-this.blogspot.com/2012/04/datetime-default-now-finally-available.html

Prior to 5.6.5, you need to use the TIMESTAMP data type, which automatically updates whenever the record is modified. Unfortunately, however, only one auto-updated TIMESTAMP field can exist per table.

CREATE TABLE mytable (
  mydate TIMESTAMP
)

See: http://dev.mysql.com/doc/refman/5.1/en/create-table.html

If you want to prevent MySQL from updating the timestamp value on UPDATE (so that it only triggers on INSERT) you can change the definition to:

CREATE TABLE mytable (
  mydate TIMESTAMP DEFAULT CURRENT_TIMESTAMP
)

T-SQL XOR Operator

The xor operator is ^

For example: SELECT A ^ B where A and B are integer category data types.

Display Back Arrow on Toolbar

If you don't want to create a custom Toolbar, you can do like this

public class GalleryActivity extends AppCompatActivity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        ...  
        getSupportActionBar().setTitle("Select Image");
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == android.R.id.home) {
            finish();
        }
        return super.onOptionsItemSelected(item);
    }
}                     

In you AndroidManifest.xml

<activity
    android:name=".GalleryActivity"
    android:theme="@style/Theme.AppCompat.Light">        
</activity>

you can also put this android:theme="@style/Theme.AppCompat.Light" to <aplication> tag, for apply to all activities

enter image description here

Editor does not contain a main type

I had the same problem. I tried all sorts of things. And I came to know that

  1. My .java files were not linked and
  2. they were not placed in the 'src' folder.

Things I did:

Project properties >> Java Build Path >> Source

  • Deleted the original 'src' folder which was empty using 'Remove' option
  • Added the source that contained my source .java files using the 'Add Folder' option

This solved the error.

How can I render HTML from another file in a React component?

It is common to have components that are only rendering from props. Like this:

class Template extends React.Component{
  render (){
    return <div>this.props.something</div>
  }
}

Then in your upper level component where you have the logic you just import the Template component and pass the needed props. All your logic stays in the higher level component, and the Template only renders. This is a possible way to achieve 'templates' like in Angular.

There is no way to have .jsx file with jsx only and use it in React because jsx is not really html but markup for a virtual DOM, which React manages.

Running a command in a new Mac OS X Terminal window

A colleague asked me how to open A LOT of ssh sessions at once. I used cobbal's answer to write this script:

tmpdir=$( mktemp -d )
trap '$DEBUG rm -rf $tmpdir ' EXIT
index=1

{
cat <<COMMANDS
ssh user1@host1
ssh user2@host2
COMMANDS
} | while read command
do 
  COMMAND_FILE=$tmpdir/$index.command
  index=$(( index + 1 ))
  echo $command > $COMMAND_FILE
  chmod +x  $COMMAND_FILE
  open $COMMAND_FILE
done
sleep 60

By updating the list of commands ( they don't have to be ssh invocations ), you will get an additional open window for every command executed. The sleep 60 at the end is there to keep the .command files around while they are being executed. Otherwise, the shell completes too quickly, executing the trap to delete the temp directory ( created by mktemp ) before the launched sessions have an opportunity to read the files.

Socket accept - "Too many open files"

Use lsof -u `whoami` | wc -l to find how many open files the user has

Convert from enum ordinal to enum type

Every enum has name(), which gives a string with the name of enum member.

Given enum Suit{Heart, Spade, Club, Diamond}, Suit.Heart.name() will give Heart.

Every enum has a valueOf() method, which takes an enum type and a string, to perform the reverse operation:

Enum.valueOf(Suit.class, "Heart") returns Suit.Heart.

Why anyone would use ordinals is beyond me. It may be nanoseconds faster, but it is not safe, if the enum members change, as another developer may not be aware some code is relying on ordinal values (especially in the JSP page cited in the question, network and database overhead completely dominates the time, not using an integer over a string).

How to resolve "could not execute statement; SQL [n/a]; constraint [numbering];"?

Overall:You persist entity that is violating database rules like as saving entity that has varchar field over 250 chars ,something like that.

In my case it was a squishy problem with TestEntityManager ,because it use HSQL database /in memory database/ and it persist the user but when you try to find it ,it drops the same exception :/

@RunWith(SpringRunner.class)
@ContextConfiguration(classes= Application.class)
@DataJpaTest
@ActiveProfiles("test")
public class UserServicesTests {

@Autowired
private TestEntityManager testEntityManager;

@Autowired
private UserRepository userRepository;

@Test
public void oops() {
    User user = new User();
    user.setUsername("Toshko");
    //EMAIL IS REQUIRED:
    //user.setEmail("OPS");
    this.testEntityManager.persist(user);

    //HERE COMES TE EXCEPTION BECAUSE THE EMAIL FIELD IN TE DATABASE IS REQUIRED :
    this.userRepository.findUserByUsername("Toshko");

    System.out.println();
}
}

show all tables in DB2 using the LIST command

have you installed a user db2inst2, i think, i remember, that db2inst1 is very administrative

What is a smart pointer and when should I use one?

A smart pointer is an object that acts like a pointer, but additionally provides control on construction, destruction, copying, moving and dereferencing.

One can implement one's own smart pointer, but many libraries also provide smart pointer implementations each with different advantages and drawbacks.

For example, Boost provides the following smart pointer implementations:

  • shared_ptr<T> is a pointer to T using a reference count to determine when the object is no longer needed.
  • scoped_ptr<T> is a pointer automatically deleted when it goes out of scope. No assignment is possible.
  • intrusive_ptr<T> is another reference counting pointer. It provides better performance than shared_ptr, but requires the type T to provide its own reference counting mechanism.
  • weak_ptr<T> is a weak pointer, working in conjunction with shared_ptr to avoid circular references.
  • shared_array<T> is like shared_ptr, but for arrays of T.
  • scoped_array<T> is like scoped_ptr, but for arrays of T.

These are just one linear descriptions of each and can be used as per need, for further detail and examples one can look at the documentation of Boost.

Additionally, the C++ standard library provides three smart pointers; std::unique_ptr for unique ownership, std::shared_ptr for shared ownership and std::weak_ptr. std::auto_ptr existed in C++03 but is now deprecated.

Restful API service

Robby provides a great answer, though I can see you still looking for more information. I implemented REST api calls the easy BUT wrong way. It wasn't until watching this Google I/O video that I understood where I went wrong. It's not as simple as putting together an AsyncTask with a HttpUrlConnection get/put call.

How do I change the ID of a HTML element with JavaScript?

It does work in Firefox (including 2.0.0.20). See http://jsbin.com/akili (add /edit to the url to edit):

<p id="one">One</p>
<a href="#" onclick="document.getElementById('one').id = 'two'; return false">Link2</a>

The first click changes the id to "two", the second click errors because the element with id="one" now can't be found!

Perhaps you have another element already with id="two" (FYI you can't have more than one element with the same id).

How can I remove space (margin) above HTML header?

This css allowed chrome and firefox to render all other elements on my page normally and remove the margin above my h1 tag. Also, as a page is resized em can work better than px.

h1 {
  margin-top: -.3em;
  margin-bottom: 0em;
}

Insert all values of a table into another table in SQL

Try this:

INSERT INTO newTable SELECT * FROM initial_Table

Get URL query string parameters

For getting each node in the URI, you can use function explode() to $_SERVER['REQUEST_URI']. If you want to get strings without knowing if it is passed or not. you may use the function I defined myself to get query parameters from $_REQUEST (as it works both for POST and GET params).

function getv($key, $default = '', $data_type = '')
{
    $param = (isset($_REQUEST[$key]) ? $_REQUEST[$key] : $default);

    if (!is_array($param) && $data_type == 'int') {
        $param = intval($param);
    }

    return $param;
}

There might be some cases when we want to get query parameters converted into Integer type, so I added the third parameter to this function.

How do I catch a numpy warning like it's an exception (not just for testing)?

To elaborate on @Bakuriu's answer above, I've found that this enables me to catch a runtime warning in a similar fashion to how I would catch an error warning, printing out the warning nicely:

import warnings

with warnings.catch_warnings():
    warnings.filterwarnings('error')
    try:
        answer = 1 / 0
    except Warning as e:
        print('error found:', e)

You will probably be able to play around with placing of the warnings.catch_warnings() placement depending on how big of an umbrella you want to cast with catching errors this way.

Measure string size in Bytes in php

Further to PhoneixS answer to get the correct length of string in bytes - Since mb_strlen() is slower than strlen(), for the best performance one can check "mbstring.func_overload" ini setting so that mb_strlen() is used only when it is really required:

$content_length = ini_get('mbstring.func_overload') ? mb_strlen($content , '8bit') : strlen($content);

pip connection failure: cannot fetch index base URL http://pypi.python.org/simple/

You can try with this below command:

python -m pip install --trusted-host https://pypi.python.org deepdiff

it will work.

How do I prevent and/or handle a StackOverflowException?

You can read up this property every few calls, Environment.StackTrace , and if the stacktrace exceded a specific threshold that you preset, you can return the function.

You should also try to replace some recursive functions with loops.

Does a foreign key automatically create an index?

Say you have a big table called orders, and a small table called customers. There is a foreign key from an order to a customer. Now if you delete a customer, Sql Server must check that there are no orphan orders; if there are, it raises an error.

To check if there are any orders, Sql Server has to search the big orders table. Now if there is an index, the search will be fast; if there is not, the search will be slow.

So in this case, the slow delete could be explained by the absence of an index. Especially if Sql Server would have to search 15 big tables without an index.

P.S. If the foreign key has ON DELETE CASCADE, Sql Server still has to search the order table, but then to remove any orders that reference the deleted customer.

Do checkbox inputs only post data if they're checked?

Yes, standard behaviour is the value is only sent if the checkbox is checked. This typically means you need to have a way of remembering what checkboxes you are expecting on the server side since not all the data comes back from the form.

The default value is always "on", this should be consistent across browsers.

This is covered in the W3C HTML 4 recommendation:

Checkboxes (and radio buttons) are on/off switches that may be toggled by the user. A switch is "on" when the control element's checked attribute is set. When a form is submitted, only "on" checkbox controls can become successful.

Different ways of loading a file as an InputStream

It Works , try out this :

InputStream in_s1 =   TopBrandData.class.getResourceAsStream("/assets/TopBrands.xml");

How to use: while not in

while not any( x in ('AND','OR','NOT') for x in list)

EDIT:

thank you for the upvotes , but etarion's solution is better since it tests if the words AND, OR, NOT are in the list, that is to say 3 tests.

Mine does as many tests as there are words in list.

EDIT2:

Also there is

while not ('AND' in list,'OR' in list,'NOT' in list)==(False,False,False)

c++ bool question

Yes that is correct. "Boolean variables only have two possible values: true (1) and false (0)." cpp tutorial on boolean values

How to manage exceptions thrown in filters in Spring?

It's strange because @ControllerAdvice should works, are you catching the correct Exception?

@ControllerAdvice
public class GlobalDefaultExceptionHandler {

    @ResponseBody
    @ExceptionHandler(value = DataAccessException.class)
    public String defaultErrorHandler(HttpServletResponse response, DataAccessException e) throws Exception {
       response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());
       //Json return
    }
}

Also try to catch this exception in CorsFilter and send 500 error, something like this

@ExceptionHandler(DataAccessException.class)
@ResponseBody
public String handleDataException(DataAccessException ex, HttpServletResponse response) {
    response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());
    //Json return
}

How to store Java Date to Mysql datetime with JPA

see in the link :

http://www.coderanch.com/t/304851/JDBC/java/Java-date-MySQL-date-conversion

The following code just solved the problem:

java.util.Date dt = new java.util.Date();

java.text.SimpleDateFormat sdf = 
     new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String currentTime = sdf.format(dt);

This 'currentTime' was inserted into the column whose type was DateTime and it was successful.

How to validate a credit card number

You can use this snippet to validate 16 digits card numbers with the Luhn algorithm:

function validateCardNumber(number) {
    var regex = new RegExp("^[0-9]{16}$");
    if (!regex.test(number))
        return false;

    return luhnCheck(number);
}

function luhnCheck(val) {
    var sum = 0;
    for (var i = 0; i < val.length; i++) {
        var intVal = parseInt(val.substr(i, 1));
        if (i % 2 == 0) {
            intVal *= 2;
            if (intVal > 9) {
                intVal = 1 + (intVal % 10);
            }
        }
        sum += intVal;
    }
    return (sum % 10) == 0;
}

How to retrieve the dimensions of a view?

I tried to use onGlobalLayout() to do some custom formatting of a TextView, but as @George Bailey noticed, onGlobalLayout() is indeed called twice: once on the initial layout path, and second time after modifying the text.

View.onSizeChanged() works better for me because if I modify the text there, the method is called only once (during the layout pass). This required sub-classing of TextView, but on API Level 11+ View. addOnLayoutChangeListener() can be used to avoid sub-classing.

One more thing, in order to get correct width of the view in View.onSizeChanged(), the layout_width should be set to match_parent, not wrap_content.

npm install from Git in a specific version

A dependency has to be available from the registry to be installed just by specifying a version descriptor.

You can certainly create and use your own registry instead of registry.npmjs.org if your projects shouldn't be shared publicly.

But, if it's not in a registry, it'll have to be referenced by URL or Git URL. To specify a version with a Git URL, include an appropriate <commit-ish>, such as a tag, at the end as a URL fragment.

Example, for a tag named 0.3.1:

"dependencies": {
  "myprivatemodule": "[email protected]:...#0.3.1"
}

Note: The above snippet shows the base URL the same as it was posted in the question.

The snipped portion (...) should be filled in:

"myprivatemodule": "[email protected]:{owner}/{project}.git#0.3.1"

And, a different address format will be needed when SSH access isn't available:

"myprivatemodule": "git://github.com/{owner}/{project}.git#0.3.1"

Depending on your OS, you may also be able to link to the dependency in another folder where you have it cloned from Github.

How to break line in JavaScript?

Here you are ;-)

<script type="text/javascript">
    alert("Hello there.\nI am on a second line ;-)")
</script>

Leading zeros for Int in Swift

Details

Xcode 9.0.1, swift 4.0

Solutions

Data

import Foundation

let array = [0,1,2,3,4,5,6,7,8]

Solution 1

extension Int {

    func getString(prefix: Int) -> String {
        return "\(prefix)\(self)"
    }

    func getString(prefix: String) -> String {
        return "\(prefix)\(self)"
    }
}

for item in array {
    print(item.getString(prefix: 0))
}

for item in array {
    print(item.getString(prefix: "0x"))
}

Solution 2

for item in array {
    print(String(repeatElement("0", count: 2)) + "\(item)")
}

Solution 3

extension String {

    func repeate(count: Int, string: String? = nil) -> String {

        if count > 1 {
            let repeatedString = string ?? self
            return repeatedString + repeate(count: count-1, string: repeatedString)
        }
        return self
    }
}

for item in array {
    print("0".repeate(count: 3) + "\(item)")
}

How can I read numeric strings in Excel cells as string (not numbers)?

Do you control the excel worksheet in anyway? Is there a template the users have for giving you the input? If so, you can have code format the input cells for you.

How to determine the number of days in a month in SQL Server?

select first_day=dateadd(dd,-1*datepart(dd,getdate())+1,getdate()), last_day=dateadd(dd,-1*datepart(dd,dateadd(mm,1,getdate())),dateadd(mm,1,getdate())), no_of_days = 1+datediff(dd,dateadd(dd,-1*datepart(dd,getdate())+1,getdate()),dateadd(dd,-1*datepart(dd,dateadd(mm,1,getdate())),dateadd(mm,1,getdate())))

replace any date with getdate to get the no of months in that particular date

How do I build an import library (.lib) AND a DLL in Visual C++?

OK, so I found the answer from http://binglongx.wordpress.com/2009/01/26/visual-c-does-not-generate-lib-file-for-a-dll-project/ says that this problem was caused by not exporting any symbols and further instructs on how to export symbols to create the lib file. To do so, add the following code to your .h file for your DLL.

#ifdef BARNABY_EXPORTS
#define BARNABY_API __declspec(dllexport)
#else
#define BARNABY_API __declspec(dllimport)
#endif

Where BARNABY_EXPORTS and BARNABY_API are unique definitions for your project. Then, each function you export you simply precede by:

BARNABY_API int add(){
}

This problem could have been prevented either by clicking the Export Symbols box on the new project DLL Wizard or by voting yes for lobotomies for computer programmers.