Programs & Examples On #Testing

Software testing is any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results.

iOS Simulator to test website on Mac

iPhoney is designed specifically for Mac users

you can read about it and download it here

How do I run all Python unit tests in a directory?

I have used the discover method and an overloading of load_tests to achieve this result in a (minimal, I think) number lines of code:

def load_tests(loader, tests, pattern):
''' Discover and load all unit tests in all files named ``*`` in ``./src/``
    suite = TestSuite()
    for all_test_suite in'src', pattern='*'):
        for test_suite in all_test_suite:
    return suite

if __name__ == '__main__':

Execution on fives something like

Ran 27 tests in 0.187s

Load vs. Stress testing

Load Testing: Load testing is meant to test the system by constantly and steadily increasing the load on the system till the time it reaches the threshold limit.

Example For example, to check the email functionality of an application, it could be flooded with 1000 users at a time. Now, 1000 users can fire the email transactions (read, send, delete, forward, reply) in many different ways. If we take one transaction per user per hour, then it would be 1000 transactions per hour. By simulating 10 transactions/user, we could load test the email server by occupying it with 10000 transactions/hour.

Stress Testing: Under stress testing, various activities to overload the existing resources with excess jobs are carried out in an attempt to break the system down.

Example: As an example, a word processor like Writer1.1.0 by is utilized in development of letters, presentations, spread sheets etc… Purpose of our stress testing is to load it with the excess of characters.

To do this, we will repeatedly paste a line of data, till it reaches its threshold limit of handling large volume of text. As soon as the character size reaches 65,535 characters, it would simply refuse to accept more data. The result of stress testing on Writer 1.1.0 produces the result that, it does not crash under the stress and that it handle the situation gracefully, which make sure that application is working correctly even under rigorous stress conditions.

Can I run multiple versions of Google Chrome on the same machine? (Mac or Windows)

I've recently stumbled upon the following solution to this problem:

Source: Multiple versions of Chrome

...this is registry data problem: How to do it then (this is an example for and, I'll try it with next versions as they will come, let's assume I've started with Chrome 2):

  1. Install Chrome 2, you'll find it Application Data folder, since I'm from Czech Republic and my name is Bronislav Klucka the path looks like this:

    C:\Documents and Settings\Bronislav Klucka\Local Settings\Data aplikací\Google\Chrome

    and run Chrome

  2. Open registry and save


    keys, put them into one chrome2.reg file and copy this file next to chrome.exe (ChromeDir\Application)

  3. Rename Chrome folder to something else (e.g. Chrome2)

  4. Install Chrome 3, it will install to Chrome folder again and run Chrome

  5. Save the same keys (there are changes due to different version) and save it to the chrome3.reg file next to chrome.exe file of this new version again
  6. Rename the folder again (e.g. Chrome3)

    the result would be that there is no Chrome dir (only Chrome2 and Chrome3)

  7. Go to the Application folder of Chrome2, create chrome.bat file with this content:

    @echo off
    regedit /S chrome2.reg
    START chrome.exe -user-data-dir="C:\Docume~1\Bronis~1\LocalS~1\Dataap~1\Google\Chrome2\User Data"
    rem START chrome.exe -user-data-dir="C:\Documents and Settings\Bronislav Klucka\Local Settings\Data aplikací\Google\Chrome2\User Data"

    the first line is generic batch command, the second line will update registry with the content of chrome2.reg file, the third lines starts Chrome pointing to passed directory, the 4th line is commented and will not be run.

    Notice short name format passed as -user-data-dir parameter (the full path is at the 4th line), the problem is that Chrome using this parameter has a problem with diacritics (Czech characters)

  8. Do 7. again for Chrome 3, update paths and reg file name in bat file for Chrome 3

Try running both bat files, seems to be working, both versions of Chrome are running simultaneously.

Updating: Running "About" dialog displays correct version, but an error while checking for new one. To correct that do (I'll explain form Chrome2 folder): 1. rename Chrome2 to Chrome 2. Go to Chrome/Application folder 3. run chrome2.reg file 4. run chrome.exe (works the same for Chrome3) now the version checking works. There has been no new version of Chrome since I've find this whole solution up. But I assume that update will be downloaded to this folder so all you need to do is to update reg file after update and rename Chrome folder back to Chrome2. I'll update this post after successful Chrome update.

Bronislav Klucka

jquery (or pure js) simulate enter key pressed for testing

Demo Here

var e = jQuery.Event("keypress");
e.which = 13; //choose the one you want
e.keyCode = 13;

Trying to mock, but not working

You can mock datetime using this:

In the module

import datetime

class ShowTime:
    def current_date():

In your

from unittest import TestCase, mock
import datetime

class TestShowTime(TestCase):
    def setUp(self) -> None: = sources.ShowTime()

    def test_current_date(self, date_mock): = datetime.datetime(year=2019, month=10, day=1)
        current_date =
        self.assertEqual(current_date, '2019-10-01')

Best way to compare 2 XML documents in Java

skaffman seems to be giving a good answer.

another way is probably to format the XML using a commmand line utility like xmlstarlet( and then format both the strings and then use any diff utility(library) to diff the resulting output files. I don't know if this is a good solution when issues are with namespaces.

What's the difference between a mock & stub?

Both Stubs and Mocks override external dependencies but the difference is

Stubs -> To Test Data

Mocks -> To Test Behavior

Fake/Dummy -> Test nothing (just override functionality with empty methods, eg replace Logger to avoid any logging noise while testing)

What is the difference between mocking and spying when using Mockito?

Spy can be useful when you want to create unit tests for legacy code.

I have created a runable example here , I copy some of it here.

If you have something like this code:

public void transfer(  DepositMoneyService depositMoneyService, WithdrawMoneyService withdrawMoneyService, 
             double amount, String fromAccount, String toAccount){

You may don't need spy because you can just mock DepositMoneyService and WithdrawMoneyService.

But with some, legacy code, dependency is in the code like this:

    public void transfer(String fromAccount, String toAccount, double amount){

        this.depositeMoneyService = new DepositMoneyService();
        this.withdrawMoneyService = new WithdrawMoneyService();


Yes, you can change to the first code but then API is changed. If this method is being used by many places, you have to change all of them.

Alternative is that you can extract the dependency out like this:

    public void transfer(String fromAccount, String toAccount, double amount){
        this.depositeMoneyService = proxyDepositMoneyServiceCreator();
        this.withdrawMoneyService = proxyWithdrawMoneyServiceCreator();

    DepositMoneyService proxyDepositMoneyServiceCreator() {
        return new DepositMoneyService();

    WithdrawMoneyService proxyWithdrawMoneyServiceCreator() {
        return new WithdrawMoneyService();

Then you can use the spy the inject the dependency like this:

DepositMoneyService mockDepositMoneyService = mock(DepositMoneyService.class);
        WithdrawMoneyService mockWithdrawMoneyService = mock(WithdrawMoneyService.class);

    TransferMoneyService target = spy(new TransferMoneyService());



More detail in the link above.

Curl command line for consuming webServices?

curl -H "Content-Type: text/xml; charset=utf-8" \
-H "SOAPAction:" \
-d @soap.txt -X POST http://someurl

ScalaTest in sbt: is there a way to run a single test without tags?

I wanted to add a concrete example to accompany the other answers

You need to specify the name of the class that you want to test, so if you have the following project (this is a Play project):

Play Project

You can test just the Login tests by running the following command from the SBT console:

test:testOnly *LoginServiceSpec

If you are running the command from outside the SBT console, you would do the following:

sbt "test:testOnly *LoginServiceSpec"

What is code coverage and how do YOU measure it?

Code coverage has been explained well in the previous answers. So this is more of an answer to the second part of the question.

We've used three tools to determine code coverage.

  1. JTest - a proprietary tool built over JUnit. (It generates unit tests as well.)
  2. Cobertura - an open source code coverage tool that can easily be coupled with JUnit tests to generate reports.
  3. Emma - another - this one we've used for a slightly different purpose than unit testing. It has been used to generate coverage reports when the web application is accessed by end-users. This coupled with web testing tools (example: Canoo) can give you very useful coverage reports which tell you how much code is covered during typical end user usage.

We use these tools to

  • Review that developers have written good unit tests
  • Ensure that all code is traversed during black-box testing

estimating of testing effort as a percentage of development time

When you speak of tests, you could mean waterfall or agile test development. In an agile environment, developers should spend 50% of their time developing and maintaining tests.

But that 50% extra will save you time when the re-factoring and manual verification time comes.

toBe(true) vs toBeTruthy() vs toBeTrue()

Disclamer: This is just a wild guess

I know everybody loves an easy-to-read list:

  • toBe(<value>) - The returned value is the same as <value>
  • toBeTrue() - Checks if the returned value is true
  • toBeTruthy() - Check if the value, when cast to a boolean, will be a truthy value

    Truthy values are all values that aren't 0, '' (empty string), false, null, NaN, undefined or [] (empty array)*.

    * Notice that when you run !![], it returns true, but when you run [] == false it also returns true. It depends on how it is implemented. In other words: (!![]) === ([] == false)

On your example, toBe(true) and toBeTrue() will yield the same results.

How to unit test abstract classes: extend with stubs?

One of the main motivations for using an abstract class is to enable polymorphism within your application -- i.e: you can substitute a different version at runtime. In fact, this is very much the same thing as using an interface except the abstract class provides some common plumbing, often referred to as a Template pattern.

From a unit testing perspective, there are two things to consider:

  1. Interaction of your abstract class with it related classes. Using a mock testing framework is ideal for this scenario as it shows that your abstract class plays well with others.

  2. Functionality of derived classes. If you have custom logic that you've written for your derived classes, you should test those classes in isolation.

edit: RhinoMocks is an awesome mock testing framework that can generate mock objects at runtime by dynamically deriving from your class. This approach can save you countless hours of hand-coding derived classes.

How can I test that a variable is more than eight characters in PowerShell?

Use the length property of the [String] type:

if ($dbUserName.length -gt 8) {
    Write-Output "Please enter more than 8 characters."
    $dbUserName = Read-Host "Re-enter database username"

Please note that you have to use -gt instead of > in your if condition. PowerShell uses the following comparison operators to compare values and test conditions:

  • -eq = equals
  • -ne = not equals
  • -lt = less than
  • -gt = greater than
  • -le = less than or equals
  • -ge = greater than or equals

How to configure "Shorten command line" method for whole project in IntelliJ

Intellij 2018.2.5

Run => Edit Configurations => Choose Node on the left hand side => expand Environment => Shorten Command line options => choose Classpath file or JAR manifest

Screen shot of Run/Debug Configuration showing the command line options

How can I solve the error LNK2019: unresolved external symbol - function?

It turned out I was using .c files with .cpp files. Renaming .c to .cpp solved my problem.

Making the Android emulator run faster

Enable GPU Hardware Acceleration (in addition to Intel's HAXM), if you are using API 15 v3 or newer and SDK Tools v17+. Graphics acceleration for the emulator takes advantage of your development computer's graphics hardware, specifically its graphics processing unit (GPU), to make screen drawing faster. This gives a noticeable boost in speed.

To enable graphics acceleration enabled by default on your emulator: when creating the AVD, in the Hardware section, click New, select GPU emulation and set the value to Yes.

To enable acceleration only at runtime: use the -gpu flag while starting the emulator like this:

emulator -avd <avd_name> -gpu on

Source: Google's Using the Emulator tutorial.

python: how to send mail with TO, CC and BCC?

Email headers don't matter to the smtp server. Just add the CC and BCC recipients to the toaddrs when you send your email. For CC, add them to the CC header.

toaddr = '[email protected]'
cc = ['[email protected]','[email protected]']
bcc = ['[email protected]']
fromaddr = '[email protected]'
message_subject = "disturbance in sector 7"
message_text = "Three are dead in an attack in the sewers below sector 7."
message = "From: %s\r\n" % fromaddr
        + "To: %s\r\n" % toaddr
        + "CC: %s\r\n" % ",".join(cc)
        + "Subject: %s\r\n" % message_subject
        + "\r\n" 
        + message_text
toaddrs = [toaddr] + cc + bcc
server = smtplib.SMTP('')
server.sendmail(fromaddr, toaddrs, message)

New to unit testing, how to write great tests?

My tests just seems so tightly bound to the method (testing all codepath, expecting some inner methods to be called a number of times, with certain arguments), that it seems that if I ever refactor the method, the tests will fail even if the final behavior of the method did not change.

I think you are doing it wrong.

A unit test should:

  • test one method
  • provide some specific arguments to that method
  • test that the result is as expected

It should not look inside the method to see what it is doing, so changing the internals should not cause the test to fail. You should not directly test that private methods are being called. If you are interested in finding out whether your private code is being tested then use a code coverage tool. But don't get obsessed by this: 100% coverage is not a requirement.

If your method calls public methods in other classes, and these calls are guaranteed by your interface, then you can test that these calls are being made by using a mocking framework.

You should not use the method itself (or any of the internal code it uses) to generate the expected result dynamically. The expected result should be hard-coded into your test case so that it does not change when the implementation changes. Here's a simplified example of what a unit test should do:

    int x = 5;
    int y = -2;
    int expectedResult = 3;
    Calculator calculator = new Calculator();
    int actualResult = calculator.Add(x, y);
    Assert.AreEqual(expectedResult, actualResult);

Note that how the result is calculated is not checked - only that the result is correct. Keep adding more and more simple test cases like the above until you have have covered as many scenarios as possible. Use your code coverage tool to see if you have missed any interesting paths.

Should black box or white box testing be the emphasis for testers?

*Black-Box testing: If the source code is not available then test data is based on the function of the software without regard to how it was implemented. -strong textExamples of black-box testing are: boundary value testing and equivalence partitioning.

*White-Box testing: If the source code of the system under test is available then the test data is based on the structure of this source code. -Examples of white-box testing are: path testing and data flow testing.

Stopping an Android app from console

If all you are looking for is killing a package

pkill package_name 

should work

Selenium and xpath: finding a div with a class/id and verifying text inside

For class and text xpath-

//div[contains(@class,'Caption') and (text(),'Model saved')]


For class and id xpath-

//div[contains(@class,'gwt-HTML') and @id="alertLabel"]

Difference between acceptance test and functional test?

The answer is opinion. I worked in a lot of projects and being testmanager and issuemanager and all different roles and the descriptions in various books differ so here is my variation:

functional-testing: take the business requirements and test all of it good and thorougly from a functional viewpoint.

acceptance-testing: the "paying" customer does the testing he likes to do so that he can accept the product delivered. It depends on the customer but usually the tests are not as thorough as the functional-testing especially if it is an in-house project because the stakeholders review and trust the test results done in earlier test phases.

As I said this is my viewpoint and experience. The functional-testing is systematic and the acceptance-testing is rather the business department testing the thing.

How do I simulate a low bandwidth, high latency environment?

For macOS, there is the Network Link Conditioner that simulates configurable bandwidth, latency, and packet loss. It is contained in the Additional Tools for Xcode package. Screenshot

Verify a method call using Moq

You're checking the wrong method. Moq requires that you Setup (and then optionally Verify) the method in the dependency class.

You should be doing something more like this:

class MyClassTest
    public void MyMethodTest()
        string action = "test";
        Mock<SomeClass> mockSomeClass = new Mock<SomeClass>();

        mockSomeClass.Setup(mock => mock.DoSomething());

        MyClass myClass = new MyClass(mockSomeClass.Object);

        // Explicitly verify each expectation...
        mockSomeClass.Verify(mock => mock.DoSomething(), Times.Once());

        // ...or verify everything.
        // mockSomeClass.VerifyAll();

In other words, you are verifying that calling MyClass#MyMethod, your class will definitely call SomeClass#DoSomething once in that process. Note that you don't need the Times argument; I was just demonstrating its value.

Gradle: How to Display Test Results in the Console in Real Time?

You could run Gradle with INFO logging level on the command line. It'll show you the result of each test while they are running. Downside is that you will get far more output for other tasks also.

gradle test -i

What is the difference between smoke testing and sanity testing?

Smoke testing

Suppose a new build of an app is ready from the development phase.

We check if we are able to open the app without a crash. We login to the app. We check if the user is redirected to the proper URL and that the environment is stable. If the main aim of the app is to provide a "purchase" functionality to the user, check if the user's ID is redirected to the buying page.

After the smoke testing we confirm the build is in a testable form and is ready to go through sanity testing.

Sanity testing

In this phase, we check the basic functionalities, like

  1. login with valid credentials,
  2. login with invalid credentials,
  3. user's info are properly displayed after logging in,
  4. making a purchase order with a certain user's id,
  5. the "thank you" page is displayed after the purchase

How do you test running time of VBA code?

We've used a solution based on timeGetTime in winmm.dll for millisecond accuracy for many years. See

The article is in German, but the code in the download (a VBA class wrapping the dll function call) is simple enough to use and understand without being able to read the article.

Select a date from date picker using Selenium webdriver

This one worked like a charm for me where the date picker just has previous and next buttons and Month and year as texts.

Page objects are as follows

    [FindsBy(How =How.ClassName, Using = "ui-datepicker-calendar")]
    public IWebElement tblCalendar;

    [FindsBy(How = How.XPath, Using = "//a[@title=\"Prev\"]")]
    public IWebElement btnPrevious;

    [FindsBy(How = How.XPath, Using = "//a[@title=\"Next\"]")]
    public IWebElement btnNext;

    [FindsBy(How = How.ClassName, Using = "ui-datepicker-year")]
    public IWebElement lblYear;

    [FindsBy(How = How.ClassName, Using = "ui-datepicker-month")]
    public IWebElement lblMonth;

    public void SelectDateFromDatePicker(string year, string month, string date)

        while (year != lblYear.Text)
            if (int.Parse(year) < int.Parse(lblYear.Text))

        while (lblMonth.Text != "January")

        while (month != lblMonth.Text)

        IWebElement dateField = PropertiesCollection.driver.FindElement(By.XPath("//a[text()=\""+ date+"\"]"));

How-to turn off all SSL checks for postman for a specific site

There is an option in Postman if you download it from instead of the chrome store (most probably it has been introduced in the new versions and the chrome one will be updated later) not sure about the old ones.

In the settings, turn off the SSL certificate verification option enter image description here

Be sure to remember to reactivate it afterwards, this is a security feature.

If you really want to use the chrome app, you could always add an exception to chrome for the url: Enter the url you would like to open in the chrome browser, you'll get a warning with a link at the bottom of the page to add an exception, which if you do, it will also allow postman to access your url. But the first option of using the postman stand-alone app is much better.

I hope this can help.

Should I test private methods or only public ones?

I understand the point of view where private methods are considered as implementations details and then don't have to be tested. And I would stick with this rule if we had to develop outside of the object only. But us, are we some kind of restricted developers who are developing only outside of objects, calling only their public methods? Or are we actually also developing that object? As we are not bound to program outside objects, we will probably have to call those private methods into new public ones we are developing. Wouldn't it be great to know that the private method resist against all odds?

I know some people could answer that if we are developing another public method into that object then this one should be tested and that's it (the private method could carry on living without test). But this is also true for any public methods of an object: when developing a web app, all the public methods of an object are called from controllers methods and hence could be considered as implementation details for controllers.

So why are we unit testing objects? Because it is really difficult, not to say impossible to be sure that we are testing the controllers' methods with the appropriate input which will trigger all the branches of the underlying code. In other words, the higher we are in the stack, the more difficult it is to test all the behaviour. And so is the same for private methods.

To me the frontier between private and public methods is a psychologic criteria when it comes to tests. Criteria which matters more to me are:

  • is the method called more than once from different places?
  • is the method sophisticated enough to require tests?

What are unit tests, integration tests, smoke tests, and regression tests?

  • Unit test: an automatic test to test the internal workings of a class. It should be a stand-alone test which is not related to other resources.
  • Integration test: an automatic test that is done on an environment, so similar to unit tests but with external resources (db, disk access)
  • Regression test: after implementing new features or bug fixes, you re-test scenarios which worked in the past. Here you cover the possibility in which your new features break existing features.
  • Smoke testing: first tests on which testers can conclude if they will continue testing.

How to run only one unit test class using Gradle

In case you have a multi-module project :

let us say your module structure is

 -> a-module
 -> b-module

and the test(testToRun) you are looking to run is in b-module, with full path :

As here you are interested to run the test in b-module, so you should see the tasks available for b-module.

./gradlew :b-module:tasks

The above command will list all tasks in b-module with description. And in ideal case, you will have a task named test to run the unit tests in that module.

./gradlew :b-module:test

Now, you have reached the point for running all the tests in b-module, finally you can pass a parameter to the above task to run tests which matches the certain path pattern

./gradlew :b-module:test --tests ""

Now, instead of this if you run

./gradlew test --tests ""

It will run the test task for both module a and b, which might result in failure as there is nothing matching the above pattern in a-module.

Order of execution of tests in TestNG

In TestNG, you use dependsOnMethods and/or dependsOnGroups:

@Test(groups = "a")
public void f1() {}

@Test(groups = "a")
public void f2() {}

@Test(dependsOnGroups = "a")
public void g() {}

In this case, g() will only run after f1() and f2() have completed and succeeded.

You will find a lot of examples in the documentation:

Simulate a button click in Jest

You may use something like this to call the handler written on click:

import { shallow } from 'enzyme'; // Mount is not required

page = <MyCoolPage />;
pageMounted = shallow(page);

// The below line will execute your click function

Switch tabs using Selenium WebDriver with Java

Please see below:

WebDriver driver = new FirefoxDriver();

String oldTab = driver.getWindowHandle();

//For opening window in New Tab
String selectLinkOpeninNewTab = Keys.chord(Keys.CONTROL,Keys.RETURN); 
driver.findElement(By.linkText("Hotels & Lounge")).sendKeys(selectLinkOpeninNewTab);

// Perform Ctrl + Tab to focus on new Tab window
new Actions(driver).sendKeys(Keys.chord(Keys.CONTROL, Keys.TAB)).perform();

// Switch driver control to focused tab window


Hope this is helpful!

Writing unit tests in Python: How do I start?

There are, in my opinion, three great python testing frameworks that are good to check out.
unittest - module comes standard with all python distributions
nose - can run unittest tests, and has less boilerplate.
pytest - also runs unittest tests, has less boilerplate, better reporting, lots of cool extra features

To get a good comparison of all of these, read through the introductions to each at
There's also extended articles on fixtures, and more there.

Is there a Social Security Number reserved for testing/examples?

Please look at this document

The SSA is instituting a new policy the where all previously unused sequences are will be available for use.

Goes into affect June 25, 2011.

Taken from the new FAQ:

What changes will result from randomization?

The SSA will eliminate the geographical significance of the first three digits of the SSN, currently referred to as the area number, by no longer allocating the area numbers for assignment to individuals in specific states. The significance of the highest group number (the fourth and fifth digits of the SSN) for validation purposes will be eliminated. Randomization will also introduce previously unassigned area numbers for assignment excluding area numbers 000, 666 and 900-999. Top

Will SSN randomization assign group number (the fourth and fifth digits of the SSN) 00 or serial number (the last four digits of the SSN) 0000?

SSN randomization will not assign group number 00 or serial number 0000. SSNs containing group number 00 or serial number 0000 will continue to be invalid.

Exception in thread "main" java.lang.Error: Unresolved compilation problems

Your problem is in this line: Message messageObject = new Message ();
This error says that the Message class is not known at compile time.

So you need to import the Message class.

Something like this:

import package1.package2.Message;

Check this out.

ReferenceError: describe is not defined NodeJs

You can also do like this:

  var mocha = require('mocha')
  var describe = mocha.describe
  var it =
  var assert = require('chai').assert

  describe('#indexOf()', function() {
    it('should return -1 when not present', function() {
      assert.equal([1,2,3].indexOf(4), -1)


Automated testing for REST Api

I have used TestNG and Apache HTTP classes to build my own REST API test framework, I developed this concept after working in Selenium for two years.

Everything is same, except you should use Apache HTTP classes instead of Selenium classes.

give a try, its really cute and good, you've all the power to customize your test framework to your fullest possibilities.

How to identify and switch to the frame in selenium webdriver when frame does not have id

I think I can add something here.

Situation I faced

  1. I cannot or not easily use the debug tools or inspection tools like firebug to see which frame I am currently at and want to go to.

  2. The XPATH/CSS selector etc. that the inspection tool told me doesn't work since the current frame is not the target one. e.g. I need to first switch to a sub-frame to be able to access/locate the element from XPATH or any other reference.

In short, the find_element() or find_elements() method doesn't apply in my case.

Wait Wait! not exactly

unless we use some fazzy search method.

use find_elements() with contains(@id,"frame") to filter out the potential frames.



Then use switchTo() to switch to that frame and hopefully the underlying XPATH for your target element can be accessed this time.

If you're similar unlucky like me, iteration might need to be done for the found frames and even iterate deeper in more layers.

e.g. This is the piece I use.

    elf1 = mydriver.find_elements(By.XPATH,'//*[contains(@id,"rame")]')
    elf2 = mydriver.find_elements(By.XPATH,'//*[contains(@id,"rame")]')
    len(mydriver.page_source) ## size of source tell whether I am in the right frame 

I try out different switch_to_frame(elf1[x])/switch_to_frame(elf2[x]) combinations and finally found the wanted element by the XPATH I found from the inspection tool in browser.

    element = WebDriverWait(mydriver, 10).until(
        EC.presence_of_element_located((By.XPATH, '//*[@id="C4_W16_V17_ZSRV-HOME"]'))
    #Click the link

Spring Test & Security: How to mock authentication?

It turned out that the SecurityContextPersistenceFilter, which is part of the Spring Security filter chain, always resets my SecurityContext, which I set calling SecurityContextHolder.getContext().setAuthentication(principal) (or by using the .principal(principal) method). This filter sets the SecurityContext in the SecurityContextHolder with a SecurityContext from a SecurityContextRepository OVERWRITING the one I set earlier. The repository is a HttpSessionSecurityContextRepository by default. The HttpSessionSecurityContextRepository inspects the given HttpRequest and tries to access the corresponding HttpSession. If it exists, it will try to read the SecurityContext from the HttpSession. If this fails, the repository generates an empty SecurityContext.

Thus, my solution is to pass a HttpSession along with the request, which holds the SecurityContext:

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

import org.junit.Test;
import org.springframework.mock.web.MockHttpSession;

import eu.ubicon.webapp.test.WebappTestEnvironment;

public class Test extends WebappTestEnvironment {

    public static class MockSecurityContext implements SecurityContext {

        private static final long serialVersionUID = -1386535243513362694L;

        private Authentication authentication;

        public MockSecurityContext(Authentication authentication) {
            this.authentication = authentication;

        public Authentication getAuthentication() {
            return this.authentication;

        public void setAuthentication(Authentication authentication) {
            this.authentication = authentication;

    public void signedIn() throws Exception {

        UsernamePasswordAuthenticationToken principal = 

        MockHttpSession session = new MockHttpSession();
                new MockSecurityContext(principal));


How to check if a string array contains one string in JavaScript?

var stringArray = ["String1", "String2", "String3"];

return (stringArray.indexOf(searchStr) > -1)

JUnit: how to avoid "no runnable methods" in test utils classes

My specific case has the following scenario. Our tests

public class VenueResourceContainerTest extends BaseTixContainerTest

all extend


and JUnit was trying to run BaseTixContainerTest. Poor BaseTixContainerTest was just trying to setup the container, setup the client, order some pizza and relax... man.

As mentioned previously, you can annotate the class with


But that caused JUnit to report that test as skipped (as opposed to completely ignored).

Tests run: 4, Failures: 0, Errors: 0, Skipped: 1

That kind of irritated me.

So I made BaseTixContainerTest abstract, and now JUnit truly ignores it.

Tests run: 3, Failures: 0, Errors: 0, Skipped: 0

How to select option in drop down protractorjs e2e tests

Helper to set the an option element:

selectDropDownByText:function(optionValue) {
            element(by.cssContainingText('option', optionValue)).click(); //optionValue: dropDownOption

How can one check to see if a remote file exists using PHP?

if (false === file_get_contents("")) {
    $image = $default_image;

Should work ;)

Test if string is URL encoded in PHP

@user187291 code works and only fails when + is not encoded.

I know this is very old post. But this worked to me.

$is_encoded = preg_match('~%[0-9A-F]{2}~i', $string);
if($is_encoded) {
 $string  = urlencode(urldecode(str_replace(['+','='], ['%2B','%3D'], $string)));
} else {
  $string = urlencode($string);

How do I install jmeter on a Mac?

You have 2 options:

brew update to update homebrew packages

brew install jmeter to install jmeter

Read this blog to know how to map folders from standard jmeter to homebrew installed version.

  • Install using standard version which I would advise you to do. Steps are:

    1. Install Last compatible JDK version (7 or 8 as of JMeter 3.1).

    2. Download JMeter from here

    3. Unzip folder and run from the folder:


How to create large PDF files (10MB, 50MB, 100MB, 200MB, 500MB, 1GB, etc.) for testing purposes?

according to the command should be

pdftk file1.pdf file2.pdf file3.pdf cat output newfile.pdf

note that you should download windows version of pdftk

How do I get my Maven Integration tests to run

Another way of running integration tests with Maven is to make use of the profile feature:



Running 'mvn clean install' will run the default build. As specified above integration tests will be ignored. Running 'mvn clean install -P integration-tests' will include the integration tests (I also ignore my staging integration tests). Furthermore, I have a CI server that runs my integration tests every night and for that I issue the command 'mvn test -P integration-tests'.

How do you run a single test/spec file in RSpec?

You can also use the actual text of the *e*xample test case with -e !

So for:

it "shows the plane arrival time"

you can use

rspec path/to/spec/file.rb -e 'shows the plane arrival time'
./scripts/spec path/to/spec/file.rb -e 'shows the plane arrival time'

no need for rake here.

How to properly assert that an exception gets raised in pytest?

Have you tried to remove "pytrace=True" ?, pytrace=True) # before # after

Have you tried to run with '--fulltrace' ?

How can I time a code segment for testing performance with Pythons timeit?

Quite apart from the timing, this code you show is simply incorrect: you execute 100 connections (completely ignoring all but the last one), and then when you do the first execute call you pass it a local variable query_stmt which you only initialize after the execute call.

First, make your code correct, without worrying about timing yet: i.e. a function that makes or receives a connection and performs 100 or 500 or whatever number of updates on that connection, then closes the connection. Once you have your code working correctly is the correct point at which to think about using timeit on it!

Specifically, if the function you want to time is a parameter-less one called foobar you can use timeit.timeit (2.6 or later -- it's more complicated in 2.5 and before):

timeit.timeit('foobar()', number=1000)

You'd better specify the number of runs because the default, a million, may be high for your use case (leading to spending a lot of time in this code;-).

Unit tests vs Functional tests

My vision is

  • Unit testing. In Procedural programming unit is a procedure, in Object oriented programming unit is a class. Unit is isolated and reflects a developer perspective
  • Functional testing - more than Unit. User perspective, which describes a feature, use case, story...
    • Integration testing - check if all separately developed components work together. It can be other application, service, library, database, network etc.
      • Narrow integration test - double[About] is used. The main purpose is to check if component is configured in a right way
      • Broad integration test (End to End test, System test) - live version. The main purpose is to check if all components are configured in a right way
    • UI testing - checks if user input triggers a correct action and the UI is changed when some actions are happened
    • ...
  • Non functional testing - other cases
    • Performance testing - calculate a speed and other metrics
    • Usability testing - UX
    • ...

Testing HTML email rendering

If you are converting your HTML pages to Email. You should check Premailer,

It converts CSS to inline CSS and also tests the compatibility with major email clients.

Integration Testing POSTing an entire object to Spring MVC controller

Another way to solve with Reflection, but without marshalling:

I have this abstract helper class:

public abstract class MvcIntegrationTestUtils {

       public static MockHttpServletRequestBuilder postForm(String url,
                 Object modelAttribute, String... propertyPaths) {

              try {
                     MockHttpServletRequestBuilder form = post(url).characterEncoding(

                     for (String path : propertyPaths) {
                            form.param(path, BeanUtils.getProperty(modelAttribute, path));

                     return form;

              } catch (Exception e) {
                     throw new RuntimeException(e);

You use it like this:

// static import (optional)
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

// in your test method, populate your model attribute object (yes, works with nested properties)
BlogSetup bgs = new BlogSetup();
      bgs.getBlog().setBlogTitle("Test Blog");
      bgs.getUser().setEmail("[email protected]");

// finally put it together
            postForm("/blogs/create", bgs, "blog.blogTitle", "",
                    "user.firstName", "user.lastName", "user.password"))

I have deduced it is better to be able to mention the property paths when building the form, since I need to vary that in my tests. For example, I might want to check if I get a validation error on a missing input and I'll leave out the property path to simulate the condition. I also find it easier to build my model attributes in a @Before method.

The BeanUtils is from commons-beanutils:


Selenium: Can I set any of the attribute value of a WebElement in Selenium?

Another to answer this question available here answered by @nilesh

public void setAttributeValue(WebElement elem, String value){
    JavascriptExecutor js = (JavascriptExecutor) driver;
        elem, "value", value

this takes advantage of selenium findElementBy function where xpath can be used also.

Test process.env with Jest

I think you could try this too:

const currentEnv = process.env;
process.env = { ENV_NODE: 'whatever' };

// test code...

process.env = currentEnv;

This works for me and you don't need module things

What's the difference between unit, functional, acceptance, and integration tests?

This is very simple.

  1. Unit testing: This is the testing actually done by developers that have coding knowledge. This testing is done at the coding phase and it is a part of white box testing. When a software comes for development, it is developed into the piece of code or slices of code known as a unit. And individual testing of these units called unit testing done by developers to find out some kind of human mistakes like missing of statement coverage etc..

  2. Functional testing: This testing is done at testing (QA) phase and it is a part of black box testing. The actual execution of the previously written test cases. This testing is actually done by testers, they find the actual result of any functionality in the site and compare this result to the expected result. If they found any disparity then this is a bug.

  3. Acceptance testing: know as UAT. And this actually done by the tester as well as developers, management team, author, writers, and all who are involved in this project. To ensure the project is finally ready to be delivered with bugs free.

  4. Integration testing: The units of code (explained in point 1) are integrated with each other to complete the project. These units of codes may be written in different coding technology or may these are of different version so this testing is done by developers to ensure that all units of the code are compatible with other and there is no any issue of integration.

Is there any publicly accessible JSON data source to test with real world data?

Tumblr has a public API that provides JSON. You can get a dump of posts using a simple url like

Jest spyOn function called

In your test code your are trying to pass App to the spyOn function, but spyOn will only work with objects, not classes. Generally you need to use one of two approaches here:

1) Where the click handler calls a function passed as a prop, e.g.

class App extends Component {

  myClickFunc = () => {
      console.log('clickity clickcty');
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        <p className="App-intro" onClick={this.myClickFunc}>
          To get started, edit <code>src/App.js</code> and save to reload.

You can now pass in a spy function as a prop to the component, and assert that it is called:

describe('my sweet test', () => {
 it('clicks it', () => {
    const spy = jest.fn();
    const app = shallow(<App someCallback={spy} />)
    const p = app.find('.App-intro')

2) Where the click handler sets some state on the component, e.g.

class App extends Component {
  state = {
      aProperty: 'first'

  myClickFunc = () => {
      console.log('clickity clickcty');
          aProperty: 'second'
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        <p className="App-intro" onClick={this.myClickFunc}>
          To get started, edit <code>src/App.js</code> and save to reload.

You can now make assertions about the state of the component, i.e.

describe('my sweet test', () => {
 it('clicks it', () => {
    const app = shallow(<App />)
    const p = app.find('.App-intro')

How do I assert my exception message with JUnit Test annotation?

If using @Rule, the exception set is applied to all the test methods in the Test class.

Unit Testing C Code

There is CUnit

And Embedded Unit is unit testing framework for Embedded C System. Its design was copied from JUnit and CUnit and more, and then adapted somewhat for Embedded C System. Embedded Unit does not require std C libs. All objects are allocated to const area.

And Tessy automates the unit testing of embedded software.

How to test code dependent on environment variables using JUnit?

A lot of focus in the suggestions above on inventing ways in runtime to pass in variables, set them and clear them and so on..? But to test things 'structurally', I guess you want to have different test suites for different scenarios? Pretty much like when you want to run your 'heavier' integration test builds, whereas in most cases you just want to skip them. But then you don't try and 'invent ways to set stuff in runtime', rather you just tell maven what you want? It used to be a lot of work telling maven to run specific tests via profiles and such, if you google around people would suggest doing it via springboot (but if you haven't dragged in the springboot monstrum into your project, it seems a horrendous footprint for 'just running JUnits', right?). Or else it would imply loads of more or less inconvenient POM XML juggling which is also tiresome and, let's just say it, 'a nineties move', as inconvenient as still insisting on making 'spring beans out of XML', showing off your ultimate 600 line logback.xml or whatnot...?

Nowadays, you can just use Junit 5 (this example is for maven, more details can be found here JUnit 5 User Guide 5)


and then


and then in your favourite utility lib create a simple nifty annotation class such as

@Target({ ElementType.TYPE, ElementType.METHOD })
@EnabledIfEnvironmentVariable(named = "MAVEN_CMD_LINE_ARGS", matches = "(.*)integration-testing(.*)")
public @interface IntegrationTest {}

so then whenever your cmdline options contain -Pintegration-testing for instance, then and only then will your @IntegrationTest annotated test-class/method fire. Or, if you don't want to use (and setup) a specific maven profile but rather just pass in 'trigger' system properties by means of

mvn <cmds> -DmySystemPop=mySystemPropValue

and adjust your annotation interface to trigger on that (yes, there is also a @EnabledIfSystemProperty). Or making sure your shell is set up to contain 'whatever you need' or, as is suggested above, actually going through 'the pain' adding system env via your POM XML.

Having your code internally in runtime fiddle with env or mocking env, setting it up and then possibly 'clearing' runtime env to change itself during execution just seems like a bad, perhaps even dangerous, approach - it's easy to imagine someone will always sooner or later make a 'hidden' internal mistake that will go unnoticed for a while, just to arise suddenly and bite you hard in production later..? You usually prefer an approach entailing that 'given input' gives 'expected output', something that is easy to grasp and maintain over time, your fellow coders will just see it 'immediately'.

Well long 'answer' or maybe rather just an opinion on why you'd prefer this approach (yes, at first I just read the heading for this question and went ahead to answer that, ie 'How to test code dependent on environment variables using JUnit').

How to test an SQL Update statement before running it?

I know this is a repeat of other answers, but it has some emotional support to take the extra step for testing update :D

For testing update, hash # is your friend.

If you have an update statement like:

SET history_by="admin"
history_ip LIKE '123%'

You hash UPDATE and SET out for testing, then hash them back in:

#SET history_by="admin"
history_ip LIKE '123%'

It works for simple statements.

An additional practically mandatory solution is, to get a copy (backup duplicate), whenever using update on a production table. Phpmyadmin > operations > copy: table_yearmonthday. It just takes a few seconds for tables <=100M.

Exact time measurement for performance testing

As others said, Stopwatch should be the right tool for this. There can be few improvements made to it though, see this thread specifically: Benchmarking small code samples in C#, can this implementation be improved?.

I have seen some useful tips by Thomas Maierhofer here

Basically his code looks like:

//prevent the JIT Compiler from optimizing Fkt calls away
long seed = Environment.TickCount;

//use the second Core/Processor for the test
Process.GetCurrentProcess().ProcessorAffinity = new IntPtr(2);

//prevent "Normal" Processes from interrupting Threads
Process.GetCurrentProcess().PriorityClass = ProcessPriorityClass.High;

//prevent "Normal" Threads from interrupting this thread
Thread.CurrentThread.Priority = ThreadPriority.Highest;

//warm up

var stopwatch = new Stopwatch()
for (int i = 0; i < repetitions; i++)
    for (int j = 0; j < iterations; j++)
    print stopwatch.Elapsed.TotalMilliseconds;

Another approach is to rely on Process.TotalProcessTime to measure how long the CPU has been kept busy running the very code/process, as shown here This can reflect more real scenario since no other process affects the measurement. It does something like:

 var start = Process.GetCurrentProcess().TotalProcessorTime;
 var stop = Process.GetCurrentProcess().TotalProcessorTime;
 print (end - begin).TotalMilliseconds;

A naked, detailed implementation of the samething can be found here.

I wrote a helper class to perform both in an easy to use manner:

public class Clock
    interface IStopwatch
        bool IsRunning { get; }
        TimeSpan Elapsed { get; }

        void Start();
        void Stop();
        void Reset();

    class TimeWatch : IStopwatch
        Stopwatch stopwatch = new Stopwatch();

        public TimeSpan Elapsed
            get { return stopwatch.Elapsed; }

        public bool IsRunning
            get { return stopwatch.IsRunning; }

        public TimeWatch()
            if (!Stopwatch.IsHighResolution)
                throw new NotSupportedException("Your hardware doesn't support high resolution counter");

            //prevent the JIT Compiler from optimizing Fkt calls away
            long seed = Environment.TickCount;

            //use the second Core/Processor for the test
            Process.GetCurrentProcess().ProcessorAffinity = new IntPtr(2);

            //prevent "Normal" Processes from interrupting Threads
            Process.GetCurrentProcess().PriorityClass = ProcessPriorityClass.High;

            //prevent "Normal" Threads from interrupting this thread
            Thread.CurrentThread.Priority = ThreadPriority.Highest;

        public void Start()

        public void Stop()

        public void Reset()

    class CpuWatch : IStopwatch
        TimeSpan startTime;
        TimeSpan endTime;
        bool isRunning;

        public TimeSpan Elapsed
                if (IsRunning)
                    throw new NotImplementedException("Getting elapsed span while watch is running is not implemented");

                return endTime - startTime;

        public bool IsRunning
            get { return isRunning; }

        public void Start()
            startTime = Process.GetCurrentProcess().TotalProcessorTime;
            isRunning = true;

        public void Stop()
            endTime = Process.GetCurrentProcess().TotalProcessorTime;
            isRunning = false;

        public void Reset()
            startTime = TimeSpan.Zero;
            endTime = TimeSpan.Zero;

    public static void BenchmarkTime(Action action, int iterations = 10000)
        Benchmark<TimeWatch>(action, iterations);

    static void Benchmark<T>(Action action, int iterations) where T : IStopwatch, new()
        //clean Garbage

        //wait for the finalizer queue to empty

        //clean Garbage

        //warm up

        var stopwatch = new T();
        var timings = new double[5];
        for (int i = 0; i < timings.Length; i++)
            for (int j = 0; j < iterations; j++)
            timings[i] = stopwatch.Elapsed.TotalMilliseconds;
            print timings[i];
        print "normalized mean: " + timings.NormalizedMean().ToString();

    public static void BenchmarkCpu(Action action, int iterations = 10000)
        Benchmark<CpuWatch>(action, iterations);

Just call

Clock.BenchmarkTime(() =>

}, 10000000);


Clock.BenchmarkCpu(() =>

}, 10000000);

The last part of the Clock is the tricky part. If you want to display the final timing, its up to you to choose what sort of timing you want. I wrote an extension method NormalizedMean which gives you the mean of the read timings discarding the noise. I mean I calculate the the deviation of each timing from the actual mean, and then I discard the values which was farer (only the slower ones) from the mean of deviation (called absolute deviation; note that its not the often heard standard deviation), and finally return the mean of remaining values. This means, for instance, if timed values are { 1, 2, 3, 2, 100 } (in ms or whatever), it discards 100, and returns the mean of { 1, 2, 3, 2 } which is 2. Or if timings are { 240, 220, 200, 220, 220, 270 }, it discards 270, and returns the mean of { 240, 220, 200, 220, 220 } which is 220.

public static double NormalizedMean(this ICollection<double> values)
    if (values.Count == 0)
        return double.NaN;

    var deviations = values.Deviations().ToArray();
    var meanDeviation = deviations.Sum(t => Math.Abs(t.Item2)) / values.Count;
    return deviations.Where(t => t.Item2 > 0 || Math.Abs(t.Item2) <= meanDeviation).Average(t => t.Item1);

public static IEnumerable<Tuple<double, double>> Deviations(this ICollection<double> values)
    if (values.Count == 0)
        yield break;

    var avg = values.Average();
    foreach (var d in values)
        yield return Tuple.Create(d, avg - d);

How to create unit tests easily in eclipse

You can use my plug-in to create tests easily:

  1. highlight the method
  2. press Ctrl+Alt+Shift+U
  3. it will create the unit test for it.

The plug-in is available here. Hope this helps.

How to mock private method for testing using PowerMock?

I don't see a problem here. With the following code using the Mockito API, I managed to do just that :

public class CodeWithPrivateMethod {

    public void meaningfulPublicApi() {
        if (doTheGamble("Whatever", 1 << 3)) {
            throw new RuntimeException("boom");

    private boolean doTheGamble(String whatever, int binary) {
        Random random = new Random(System.nanoTime());
        boolean gamble = random.nextBoolean();
        return gamble;

And here's the JUnit test :

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyString;
import static org.powermock.api.mockito.PowerMockito.when;
import static;

public class CodeWithPrivateMethodTest {

    @Test(expected = RuntimeException.class)
    public void when_gambling_is_true_then_always_explode() throws Exception {
        CodeWithPrivateMethod spy = PowerMockito.spy(new CodeWithPrivateMethod());

        when(spy, method(CodeWithPrivateMethod.class, "doTheGamble", String.class, int.class))
                .withArguments(anyString(), anyInt())


How to type in textbox using Selenium WebDriver (Selenium 2) with Java?

Try this :

driver.findElement("email")).sendKeys("[email protected]");

How to write a test which expects an Error to be thrown in Jasmine?

For anyone who still might be facing this issue, for me the posted solution didn't work and it kept on throwing this error: Error: Expected function to throw an exception. I later realised that the function which I was expecting to throw an error was an async function and was expecting promise to be rejected and then throw error and that's what I was doing in my code:

throw new Error('REQUEST ID NOT FOUND');

and thats what I did in my test and it worked:

it('Test should throw error if request not found', willResolve(() => {
         const promise = service.getRequestStatus('request-id');
                return expectToReject(promise).then((err) => {
                    expect(err.message).toEqual('REQUEST NOT FOUND');

WebDriver: check if an element exists?

With version 2.21.0 of selenium-java.jar you can do this;


How to test my servlet using JUnit

First off, in a real application, you would never get database connection info in a servlet; you would configure it in your app server.

There are ways, however, of testing Servlets without having a container running. One is to use mock objects. Spring provides a set of very useful mocks for things like HttpServletRequest, HttpServletResponse, HttpServletSession, etc:

Using these mocks, you could test things like

What happens if username is not in the request?

What happens if username is in the request?


You could then do stuff like:

import static org.junit.Assert.assertEquals;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.junit.Before;
import org.junit.Test;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;

public class MyServletTest {
    private MyServlet servlet;
    private MockHttpServletRequest request;
    private MockHttpServletResponse response;

    public void setUp() {
        servlet = new MyServlet();
        request = new MockHttpServletRequest();
        response = new MockHttpServletResponse();

    public void correctUsernameInRequest() throws ServletException, IOException {
        request.addParameter("username", "scott");
        request.addParameter("password", "tiger");

        servlet.doPost(request, response);

        assertEquals("text/html", response.getContentType());

        // ... etc

Proper way to assert type of variable in Python

The isinstance built-in is the preferred way if you really must, but even better is to remember Python's motto: "it's easier to ask forgiveness than permission"!-) (It was actually Grace Murray Hopper's favorite motto;-). I.e.:

def my_print(text, begin, end):
    "Print 'text' in UPPER between 'begin' and 'end' in lower"
      print begin.lower() + text.upper() + end.lower()
    except (AttributeError, TypeError):
      raise AssertionError('Input variables should be strings')

This, BTW, lets the function work just fine on Unicode strings -- without any extra effort!-)

Mockito - NullpointerException when stubbing Method

The default return value of methods you haven't stubbed yet is false for boolean methods, an empty collection or map for methods returning collections or maps and null otherwise.

This also applies to method calls within when(...). In you're example when(myService.getListWithData(inputData).get()) will cause a NullPointerException because myService.getListWithData(inputData) is null - it has not been stubbed before.

One option is create mocks for all intermediate return values and stub them before use. For example:

ListWithData listWithData = mock(ListWithData.class);

Or alternatively, you can specify a different default answer when creating a mock, to make methods return a new mock instead of null: RETURNS_DEEP_STUBS

SomeService myService = mock(SomeService.class, Mockito.RETURNS_DEEP_STUBS);

You should read the Javadoc of Mockito.RETURNS_DEEP_STUBS which explains this in more detail and also has some warnings about its usage.

I hope this helps. Just note that your example code seems to have more issues, such as missing assert or verify statements and calling setters on mocks (which does not have any effect).

How to check whether dynamically attached event listener exists or not?

There doesn't appear to be a cross browser function that searches for events registered under a given element.

However, it is possible to view the call back functions for elements in some browsers using their development tools. This can be useful when attempting to determine how a web page functions or for debugging code.


First, view the element in the Inspector tab within the developer tools. This can be done:

  • On the page by right clicking on the item on the web page that you want to inspect and selecting "Inspect Element" from the menu.
  • Within the console by using a function to select the element, such as document.querySelector, and then clicking the icon beside the element to view it in the Inspector tab.

If any events were registered to the element, you will see a button containing the word Event beside the element. Clicking it will allow you to see the events that have been registered with the element. Clicking the arrow beside an event allows you to view the callback function for it.


First, view the element in the Elements tab within the developer tools. This can be done:

  • On the page by right clicking on the item on the web page that you want to inspect and selecting "Inspect" from the menu
  • Within the console by using a function to select the element, such as document.querySelector, right clicking the the element, and selecting "Reveal in Elements panel" to view it in the Inspector tab.

Near the section of the window that shows the tree containing the web page elements, there should be another section with a tab entitled "Event Listeners". Select it to see events that were registered to the element. To see the code for a given event, click the link to the right of it.

In Chrome, events for an element can also be found using the getEventListeners function. However, based on my tests, the getEventListeners function doesn't list events when multiple elements are passed to it. If you want to find all of the elements on the page that have listeners and view the callback functions for those listeners, you can use the following code in the console to do this:

var elems = document.querySelectorAll('*');

for (var i=0; i <= elems.length; i++) {
    var listeners = getEventListeners(elems[i]);

    if (Object.keys(listeners).length < 1) {


    for (var j in listeners) {
        console.log('Event: '+j);

        for (var k=0; k < listeners[j].length; k++) {

Please edit this answer if you know of ways to do this in the given browsers or in other browsers.

How do you print in a Go test using the "testing" package?

t.Log() will not show up until after the test is complete, so if you're trying to debug a test that is hanging or performing badly it seems you need to use fmt.

Yes: that was the case up to Go 1.13 (August 2019) included.

And that was followed in issue 24929

Consider the following (silly) automated tests:

func TestFoo(t *testing.T) {

  for i := 0; i < 15; i++ {
        t.Logf("%d", i)
        time.Sleep(3 * time.Second)

func TestBar(t *testing.T) {

  for i := 0; i < 15; i++ {
        t.Logf("%d", i)
        time.Sleep(2 * time.Second)

func TestBaz(t *testing.T) {

  for i := 0; i < 15; i++ {
        t.Logf("%d", i)
        time.Sleep(1 * time.Second)

If I run go test -v, I get no log output until all of TestFoo is done, then no output until all of TestBar is done, and again no more output until all of TestBaz is done.
This is fine if the tests are working, but if there is some sort of bug, there are a few cases where buffering log output is problematic:

  • When iterating locally, I want to be able to make a change, run my tests, see what's happening in the logs immediately to understand what's going on, hit CTRL+C to shut the test down early if necessary, make another change, re-run the tests, and so on.
    If TestFoo is slow (e.g., it's an integration test), I get no log output until the very end of the test. This significantly slows down iteration.
  • If TestFoo has a bug that causes it to hang and never complete, I'd get no log output whatsoever. In these cases, t.Log and t.Logf are of no use at all.
    This makes debugging very difficult.
  • Moreover, not only do I get no log output, but if the test hangs too long, either the Go test timeout kills the test after 10 minutes, or if I increase that timeout, many CI servers will also kill off tests if there is no log output after a certain amount of time (e.g., 10 minutes in CircleCI).
    So now my tests are killed and I have nothing in the logs to tell me what happened.

But for (possibly) Go 1.14 (Q1 2020): CL 127120

testing: stream log output in verbose mode

The output now is:

=== RUN   TestFoo
=== PAUSE TestFoo
=== RUN   TestBar
=== PAUSE TestBar
=== RUN   TestGaz
=== PAUSE TestGaz
=== CONT  TestFoo
    TestFoo: main_test.go:14: hello from foo
=== CONT  TestGaz
=== CONT  TestBar
    TestGaz: main_test.go:38: hello from gaz
    TestBar: main_test.go:26: hello from bar
    TestFoo: main_test.go:14: hello from foo
    TestBar: main_test.go:26: hello from bar
    TestGaz: main_test.go:38: hello from gaz
    TestFoo: main_test.go:14: hello from foo
    TestGaz: main_test.go:38: hello from gaz
    TestBar: main_test.go:26: hello from bar
    TestFoo: main_test.go:14: hello from foo
    TestGaz: main_test.go:38: hello from gaz
    TestBar: main_test.go:26: hello from bar
    TestGaz: main_test.go:38: hello from gaz
    TestFoo: main_test.go:14: hello from foo
    TestBar: main_test.go:26: hello from bar
--- PASS: TestFoo (1.00s)
--- PASS: TestGaz (1.00s)
--- PASS: TestBar (1.00s)
ok      dummy/streaming-test    1.022s

It is indeed in Go 1.14, as Dave Cheney attests in "go test -v streaming output":

In Go 1.14, go test -v will stream t.Log output as it happens, rather than hoarding it til the end of the test run.

Under Go 1.14 the fmt.Println and t.Log lines are interleaved, rather than waiting for the test to complete, demonstrating that test output is streamed when go test -v is used.

Advantage, according to Dave:

This is a great quality of life improvement for integration style tests that often retry for long periods when the test is failing.
Streaming t.Log output will help Gophers debug those test failures without having to wait until the entire test times out to receive their output.

git repo says it's up-to-date after pull but files are not updated

For me my forked branch was not in sync with the master branch. So I went to bitbucket and synced and merged my forked branch and then tried to take the pull. Then it worked fine.

How to get the filename without the extension from a path in Python?

import os
list = []
def getFileName( path ):
for file in os.listdir(path):
    #print file
        ext = os.path.splitext(base)[1]
            newpath = path+"/"+file
            #print path
return list

print list

Java, List only subdirectories from a directory, not files

ArrayList<File> directories = new ArrayList<File>(
        new File("your/path/").listFiles(File::isDirectory)

PIL image to array (numpy array to array) - Python

I use numpy.fromiter to invert a 8-greyscale bitmap, yet no signs of side-effects

import Image
import numpy as np

im = Image.load('foo.jpg')
im = im.convert('L')

arr = np.fromiter(iter(im.getdata()), np.uint8)
arr.resize(im.height, im.width)

arr ^= 0xFF  # invert
inverted_im = Image.fromarray(arr, mode='L')

Reload .profile in bash shell script (in unix)?

Try this to reload your current shell:

source ~/.profile

VSCode single to double quote automatic replace

Well, like the guy (@user2982122) mentioned but instead of File go to Code -> Preferences -> Settings, then look for Quote, select Prettier and check both boxes

enter image description here enter image description here

Inline list initialization in VB.NET

Collection initializers are only available in VB.NET 2010, released 2010-04-12:

Dim theVar = New List(Of String) From { "one", "two", "three" }

Most popular screen sizes/resolutions on Android phones

Also, their "device dashboard" stats at:

can be pretty helpful. They are current and derived from Android Market visits.

How to get last N records with activerecord?

Just try:

Model.order("field_for_sort desc").limit(5)

What is the equivalent of "none" in django templates?

None, False and True all are available within template tags and filters. None, False, the empty string ('', "", """""") and empty lists/tuples all evaluate to False when evaluated by if, so you can easily do

{% if profile.user.first_name == None %}
{% if not profile.user.first_name %}

A hint: @fabiocerqueira is right, leave logic to models, limit templates to be the only presentation layer and calculate stuff like that in you model. An example:

# someapp/
class UserProfile(models.Model):
    user = models.OneToOneField('auth.User')
    # other fields

    def get_full_name(self):
        if not self.user.first_name:
        return ' '.join([self.user.first_name, self.user.last_name])

# template
{{ user.get_profile.get_full_name }}

Hope this helps :)

How to fix missing dependency warning when using useEffect React Hook?

You can set it directly as the useEffect callback:

useEffect(fetchBusinesses, [])

It will trigger only once, so make sure all the function's dependencies are correctly set (same as using componentDidMount/componentWillMount...)

Edit 02/21/2020

Just for completeness:

1. Use function as useEffect callback (as above)

useEffect(fetchBusinesses, [])

2. Declare function inside useEffect()

useEffect(() => {
  function fetchBusinesses() {
}, [])

3. Memoize with useCallback()

In this case, if you have dependencies in your function, you will have to include them in the useCallback dependencies array and this will trigger the useEffect again if the function's params change. Besides, it is a lot of boilerplate... So just pass the function directly to useEffect as in 1. useEffect(fetchBusinesses, []).

const fetchBusinesses = useCallback(() => {
}, [])
useEffect(() => {
}, [fetchBusinesses])

4. Disable eslint's warning

useEffect(() => {
}, []) // eslint-disable-line react-hooks/exhaustive-deps

How do I run SSH commands on remote system using Java?

You may take a look at this Java based framework for remote command execution, incl. via SSH: It relies on two opensource SSH libraries, either JSch (for this implementation even an ECDSA authentication is supported) or Ganymed (one of these two libraries will be enough). At the first glance it might look a bit complex, you'll have to prepare plenty of SSH related classes (providing server and your user details, specifying encryption details, provide OpenSSH compatible private keys, etc., but the SSH itself is quite complex too). On the other hand, the modular design allows for simple inclusion of more SSH libraries, easy implementation of other command's output processing or even interactive classes etc.

SQL Server: Multiple table joins with a WHERE clause

SELECT p.Name, v.Name
FROM Production.Product p
JOIN Purchasing.ProductVendor pv
ON p.ProductID = pv.ProductID
JOIN Purchasing.Vendor v
ON pv.BusinessEntityID = v.BusinessEntityID
WHERE ProductSubcategoryID = 15
ORDER BY v.Name;

How to convert these strange characters? (ë, Ã, ì, ù, Ã)

If you see those characters you probably just didn’t specify the character encoding properly. Because those characters are the result when an UTF-8 multi-byte string is interpreted with a single-byte encoding like ISO 8859-1 or Windows-1252.

In this case ë could be encoded with 0xC3 0xAB that represents the Unicode character ë (U+00EB) in UTF-8.

MySQL: When is Flush Privileges in MySQL really needed?

2 points in addition to all other good answers:


what are the Grant Tables?


The MySQL system database includes several grant tables that contain information about user accounts and the privileges held by them.

clari?cation: in MySQL, there are some inbuilt databases , one of them is "mysql" , all the tables on "mysql" database have been called as grant tables


note that if you perform:

UPDATE a_grant_table SET password=PASSWORD('1234') WHERE test_col = 'test_val';

and refresh phpMyAdmin , you'll realize that your password has been changed on that table but even now if you perform:

mysql -u someuser -p

your access will be denied by your new password until you perform :


How long is the SHA256 hash?

Why would you make it VARCHAR? It doesn't vary. It's always 64 characters, which can be determined by running anything into one of the online SHA-256 calculators.

Excel Macro - Select all cells with data and format as table

Try this one for current selection:

Sub A_SelectAllMakeTable2()
    Dim tbl As ListObject
    Set tbl = ActiveSheet.ListObjects.Add(xlSrcRange, Selection, , xlYes)
    tbl.TableStyle = "TableStyleMedium15"
End Sub

or equivalent of your macro (for Ctrl+Shift+End range selection):

Sub A_SelectAllMakeTable()
    Dim tbl As ListObject
    Dim rng As Range

    Set rng = Range(Range("A1"), Range("A1").SpecialCells(xlLastCell))
    Set tbl = ActiveSheet.ListObjects.Add(xlSrcRange, rng, , xlYes)
    tbl.TableStyle = "TableStyleMedium15"
End Sub

Python interpreter error, x takes no arguments (1 given)

I have been puzzled a lot with this problem, since I am relively new in Python. I cannot apply the solution to the code given by the questioned, since it's not self executable. So I bring a very simple code:

from turtle import *

ts = Screen(); tu = Turtle()

def move(x,y):
  print "move()"



As you can see, the solution consists in using two (dummy) arguments, even if they are not used either by the function itself or in calling it! It sounds crazy, but I believe there must be a reason for it (hidden from the novice!).

I have tried a lot of other ways ('self' included). It's the only one that works (for me, at least).

javascript get child by id

If the child is always going to be a specific tag then you could do it like this

function test(el)
 var children = el.getElementsByTagName('div');// any tag could be used here..

  for(var i = 0; i< children.length;i++)
    if (children[i].getAttribute('id') == 'child') // any attribute could be used here
     // do what ever you want with the element..  
     // children[i] holds the element at the moment..


Converting integer to string in Python

There are several ways to convert an integer to string in python. You can use [ str(integer here) ] function, the f-string [ f'{integer here}'], the .format()function [ '{}'.format(integer here) and even the '%s'% keyword [ '%s'% integer here]. All this method can convert an integer to string.

See below example

#Examples of converting an intger to string

#Using the str() function
number = 1
convert_to_string = str(number)
print(type(convert_to_string)) # output (<class 'str'>)

#Using the f-string
number = 1
convert_to_string = f'{number}'
print(type(convert_to_string)) # output (<class 'str'>)

#Using the  {}'.format() function
number = 1
convert_to_string = '{}'.format(number)
print(type(convert_to_string)) # output (<class 'str'>)

#Using the  '% s '% keyword
number = 1
convert_to_string = '% s '% number
print(type(convert_to_string)) # output (<class 'str'>)

Creating multiple log files of different content with log4j

Perhaps something like this?

<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="">
 <!-- general application log -->
 <appender name="MainLogFile" class="org.apache.log4j.FileAppender">
  <param name="File" value="server.log" />
  <param name="Threshold" value="INFO" />
  <layout class="org.apache.log4j.PatternLayout">
   <param name="ConversionPattern" value="%-5p %t [%-40.40c] %x - %m%n"/>
 <!-- additional fooSystem logging -->
 <appender name="FooLogFile" class="org.apache.log4j.FileAppender">
  <param name="File" value="foo.log" />
  <layout class="org.apache.log4j.PatternLayout">
   <param name="ConversionPattern" value="%-5p %t [%-40.40c] %x - %m%n"/>
 <!-- foo logging -->
 <logger name="">
  <level value="DEBUG"/>
  <appender-ref ref="FooLogFile"/>
 <!-- default logging -->
  <level value="INFO"/>
  <appender-ref ref="MainLogFile"/>

Thus, all info messages are written to server.log; by contrast, foo.log contains only messages, including debug-level messages.

Gets byte array from a ByteBuffer in java

This is a simple way to get a byte[], but part of the point of using a ByteBuffer is avoiding having to create a byte[]. Perhaps you can get whatever you wanted to get from the byte[] directly from the ByteBuffer.

what is <meta charset="utf-8">?

That meta tag basically specifies which character set a website is written with.

Here is a definition of UTF-8:

UTF-8 (U from Universal Character Set + Transformation Format—8-bit) is a character encoding capable of encoding all possible characters (called code points) in Unicode. The encoding is variable-length and uses 8-bit code units.

REST - HTTP Post Multipart with JSON

If I understand you correctly, you want to compose a multipart request manually from an HTTP/REST console. The multipart format is simple; a brief introduction can be found in the HTML 4.01 spec. You need to come up with a boundary, which is a string not found in the content, let’s say HereGoes. You set request header Content-Type: multipart/form-data; boundary=HereGoes. Then this should be a valid request body:

Content-Disposition: form-data; name="myJsonString"
Content-Type: application/json

{"foo": "bar"}
Content-Disposition: form-data; name="photo"
Content-Type: image/jpeg
Content-Transfer-Encoding: base64

<...JPEG content in base64...>

regex.test V.S. string.match to know if a string matches a regular expression

Don't forget to take into consideration the global flag in your regexp :

var reg = /abc/g;
!!'abcdefghi'.match(reg); // => true
!!'abcdefghi'.match(reg); // => true
reg.test('abcdefghi');    // => true
reg.test('abcdefghi');    // => false <=

This is because Regexp keeps track of the lastIndex when a new match is found.

Set Memory Limit in htaccess

In your .htaccess you can add:

PHP 5.x

<IfModule mod_php5.c>
    php_value memory_limit 64M

PHP 7.x

<IfModule mod_php7.c>
    php_value memory_limit 64M

If page breaks again, then you are using PHP as mod_php in apache, but error is due to something else.

If page does not break, then you are using PHP as CGI module and therefore cannot use php values - in the link I've provided might be solution but I'm not sure you will be able to apply it.


Why does LayoutInflater ignore the layout_width and layout_height layout parameters I've specified?

wanna add to main answer above
I tried to follow it but my recyclerView began to stretch every item to a screen
I had to add next line after inflating for reach to goal

itemLayoutView.setLayoutParams(new RecyclerView.LayoutParams(RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT));

I already added these params by xml but it didnot work correctly
and with this line all is ok

Switching between GCC and Clang/LLVM using CMake

System wide C change on Ubuntu:

sudo update-alternatives --config cc

System wide C++ change on Ubuntu:

sudo update-alternatives --config c++

For each of the above, press Selection number (1) and Enter to select Clang:

  Selection    Path            Priority   Status
* 0            /usr/bin/gcc     20        auto mode
  1            /usr/bin/clang   10        manual mode
  2            /usr/bin/gcc     20        manual mode
Press enter to keep the current choice[*], or type selection number:

Convert Java Date to UTC String

If XStream is a dependency, try:

new com.thoughtworks.xstream.converters.basic.DateConverter().toString(date)

Spring Security redirect to previous page after successful login

What happens after login (to which url the user is redirected) is handled by the AuthenticationSuccessHandler.

This interface (a concrete class implementing it is SavedRequestAwareAuthenticationSuccessHandler) is invoked by the AbstractAuthenticationProcessingFilter or one of its subclasses like (UsernamePasswordAuthenticationFilter) in the method successfulAuthentication.

So in order to have an other redirect in case 3 you have to subclass SavedRequestAwareAuthenticationSuccessHandler and make it to do what you want.

Sometimes (depending on your exact usecase) it is enough to enable the useReferer flag of AbstractAuthenticationTargetUrlRequestHandler which is invoked by SimpleUrlAuthenticationSuccessHandler (super class of SavedRequestAwareAuthenticationSuccessHandler).

<bean id="authenticationFilter"
    <property name="filterProcessesUrl" value="/login/j_spring_security_check" />
    <property name="authenticationManager" ref="authenticationManager" />
    <property name="authenticationSuccessHandler">
        <bean class="">
            <property name="useReferer" value="true"/>
    <property name="authenticationFailureHandler">
        <bean class="">
            <property name="defaultFailureUrl" value="/login?login_error=t" />

PHP Configuration: It is not safe to rely on the system's timezone settings

I found, bizarrely, that I could fix the errors by placing the timezone declaration at the TOP of my php.ini file.

It was already in my php.ini. Twice, actually. And I was pulling my hair out because everyone was saying there must be another ini being loaded... There wasn't.

Hope this can save someone else the time/hair loss.

How do I check if a SQL Server text column is empty?

I know there are plenty answers with alternatives to this problem, but I just would like to put together what I found as the best solution by @Eric Z Beard & @Tim Cooper with @Enrique Garcia & @Uli Köhler.

If needed to deal with the fact that space-only could be the same as empty in your use-case scenario, because the query below will return 1, not 0.

SELECT datalength(' ')

Therefore, I would go for something like:

SELECT datalength(RTRIM(LTRIM(ISNULL([TextColumn], ''))))

Bootstrap: Use .pull-right without having to hardcode a negative margin-top

just put #login-box before <h2>Welcome</h2> will be ok.

<div class='container'>
    <div class='hero-unit'>
        <div id='login-box' class='pull-right control-group'>
            <div class='clearfix'>
                <input type='text' placeholder='Username' />
            <div class='clearfix'>
                <input type='password' placeholder='Password' />
            <button type='button' class='btn btn-primary'>Log in</button>

        <p>Please log in</p>


here is jsfiddle

Java Compare Two Lists


Here are two versions. One using ArrayList and other using HashSet

Compare them and create your own version from this, until you get what you need.

This should be enough to cover the:

P.S: It is not a school assignment :) So if you just guide me it will be enough

part of your question.

continuing with the original answer:

You may use a java.util.Collection and/or java.util.ArrayList for that.

The retainAll method does the following:

Retains only the elements in this collection that are contained in the specified collection

see this sample:

import java.util.Collection;
import java.util.ArrayList;
import java.util.Arrays;

public class Repeated {
    public static void main( String  [] args ) {
        Collection listOne = new ArrayList(Arrays.asList("milan","dingo", "elpha", "hafil", "meat", "iga", "neeta.peeta"));
        Collection listTwo = new ArrayList(Arrays.asList("hafil", "iga", "binga", "mike", "dingo"));

        listOne.retainAll( listTwo );
        System.out.println( listOne );


For the second part ( similar values ) you may use the removeAll method:

Removes all of this collection's elements that are also contained in the specified collection.

This second version gives you also the similar values and handles repeated ( by discarding them).

This time the Collection could be a Set instead of a List ( the difference is, the Set doesn't allow repeated values )

import java.util.Collection;
import java.util.HashSet;
import java.util.Arrays;

class Repeated {
      public static void main( String  [] args ) {

          Collection<String> listOne = Arrays.asList("milan","iga",

          Collection<String> listTwo = Arrays.asList("hafil",

          Collection<String> similar = new HashSet<String>( listOne );
          Collection<String> different = new HashSet<String>();
          different.addAll( listOne );
          different.addAll( listTwo );

          similar.retainAll( listTwo );
          different.removeAll( similar );

          System.out.printf("One:%s%nTwo:%s%nSimilar:%s%nDifferent:%s%n", listOne, listTwo, similar, different);


$ java Repeated
One:[milan, iga, dingo, iga, elpha, iga, hafil, iga, meat, iga, neeta.peeta, iga]

Two:[hafil, iga, binga, mike, dingo, dingo, dingo]

Similar:[dingo, iga, hafil]

Different:[mike, binga, milan, meat, elpha, neeta.peeta]

If it doesn't do exactly what you need, it gives you a good start so you can handle from here.

Question for the reader: How would you include all the repeated values?

Python script to convert from UTF-8 to ASCII

data="UTF-8 DATA"

Angular2 QuickStart npm start is not working correctly

In order to get npm start running for me, I had to make sure I had globally installed some of the devDependencies. Have you tried:

  • npm install -g concurrently
  • npm install -g lite-server
  • npm install -g typescript

How can I make this try_files directive work?

a very common try_files line which can be applied on your condition is

location / {
    try_files $uri $uri/ /test/index.html;

you probably understand the first part, location / matches all locations, unless it's matched by a more specific location, like location /test for example

The second part ( the try_files ) means when you receive a URI that's matched by this block try $uri first, for example nginx will try to check if there's a file inside /images called image.jpg if found it will serve it first.

Second condition is $uri/ which means if you didn't find the first condition $uri try the URI as a directory, for example, ngixn will first check if a file called images exists then it wont find it, then goes to second check $uri/ and see if there's a directory called images exists then it will try serving it.

Side note: if you don't have autoindex on you'll probably get a 403 forbidden error, because directory listing is forbidden by default.

EDIT: I forgot to mention that if you have index defined, nginx will try to check if the index exists inside this folder before trying directory listing.

Third condition /test/index.html is considered a fall back option, (you need to use at least 2 options, one and a fall back), you can use as much as you can (never read of a constriction before), nginx will look for the file index.html inside the folder test and serve it if it exists.

If the third condition fails too, then nginx will serve the 404 error page.

Also there's something called named locations, like this

location @error {

You can call it with try_files like this

try_files $uri $uri/ @error;

TIP: If you only have 1 condition you want to serve, like for example inside folder images you only want to either serve the image or go to 404 error, you can write a line like this

location /images {
    try_files $uri =404;

which means either serve the file or serve a 404 error, you can't use only $uri by it self without =404 because you need to have a fallback option.
You can also choose which ever error code you want, like for example:

location /images {
    try_files $uri =403;

This will show a forbidden error if the image doesn't exist, or if you use 500 it will show server error, etc ..

What's the easy way to auto create non existing dir in ansible

Right now, this is the only way

- name: Ensures {{project_root}}/conf dir exists
  file: path={{project_root}}/conf state=directory
- name: Copy file
    src: code.conf.j2
    dest: "{{project_root}}/conf/code.conf"

Can't connect to local MySQL server through socket homebrew

just to complete this thread. therefore MAMP (PRO) is used pretty often

the path here is


Is there an equivalent to CTRL+C in IPython Notebook in Firefox to break cells that are running?

To add to the above: If interrupt is not working, you can restart the kernel.

Go to the kernel dropdown >> restart >> restart and clear output. This usually does the trick. If this still doesn't work, kill the kernel in the terminal (or task manager) and then restart.

Interrupt doesn't work well for all processes. I especially have this problem using the R kernel.

Fragment onResume() & onPause() is not called on backstack

Here's my more robust version of Gor's answer (using fragments.size()is unreliable due to size not being decremented after fragment is popped)

getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
        public void onBackStackChanged() {
            if (getFragmentManager() != null) {

                Fragment topFrag = NavigationHelper.getCurrentTopFragment(getFragmentManager());

                if (topFrag != null) {
                    if (topFrag instanceof YourFragment) {
                        //This fragment is being shown. 
                    } else {
                        //Navigating away from this fragment. 

And the 'getCurrentTopFragment' method:

public static Fragment getCurrentTopFragment(FragmentManager fm) {
    int stackCount = fm.getBackStackEntryCount();

    if (stackCount > 0) {
        FragmentManager.BackStackEntry backEntry = fm.getBackStackEntryAt(stackCount-1);
        return  fm.findFragmentByTag(backEntry.getName());
    } else {
        List<Fragment> fragments = fm.getFragments();
        if (fragments != null && fragments.size()>0) {
            for (Fragment f: fragments) {
                if (f != null && !f.isHidden()) {
                    return f;
    return null;

The program can't start because api-ms-win-crt-runtime-l1-1-0.dll is missing while starting Apache server on my computer

I was facing the same issue. After many tries below solution worked for me.

Before installing VC++ install your windows updates. 1. Go to Start - Control Panel - Windows Update 2. Check for the updates. 3. Install all updates. 4. Restart your system.

After that you can follow the below steps.


Download the Visual C++ Redistributable 2015

Visual C++ Redistributable for Visual Studio 2015 (64-bit)

Visual C++ Redistributable for Visual Studio 2015 (32-bit)

(Reinstal if already installed) then restart your computer or use windows updates for download auto.

For link download

Fatal error: Call to undefined function mysql_connect()

A solution could be to use adapter functions like these to start using mysqli instead of mysql over your entire application:

if (!function_exists('mysql_connect')) {
    function mysql_connect($host = '', $user = '', $password = '', $database = '', $port = 0, $socket = '') {
        return mysqli_connect($host, $user, $password, $database, $port, $socket);

if (!function_exists('mysql_select_db')) {
    function mysql_select_db($link, $dbname) {
        mysqli_select_db($link, $dbname);

pow (x,y) in Java

In Java x ^ y is an XOR operation.

How to maintain state after a page refresh in React.js?

I may be late but actual code for react-create-app for react > 16 ver. After each change state is saved in sessionStorage (not localStorage) and is crypted via crypto-js. On refresh (when user demands refresh of the page by clicking refresh button) state is loaded from the storage. I also recommend not to use sourceMaps in build to avoid readablility of the key phrases.

my index.js

import React from "react";
import ReactDOM from "react-dom";
import './index.css';
import App from './containers/App';
import * as serviceWorker from './serviceWorker';
import {createStore} from "redux";
import {Provider} from "react-redux"
import {BrowserRouter} from "react-router-dom";
import rootReducer from "./reducers/rootReducer";
import CryptoJS from 'crypto-js';

const key = CryptoJS.enc.Utf8.parse("someRandomText_encryptionPhase");
const iv = CryptoJS.enc.Utf8.parse("someRandomIV");
const persistedState = loadFromSessionStorage();

let store = createStore(rootReducer, persistedState,

function loadFromSessionStorage() {
    try {
        const serializedState = sessionStorage.getItem('state');
        if (serializedState === null) {
            return undefined;
        const decrypted = CryptoJS.AES.decrypt(serializedState, key, {iv: iv}).toString(CryptoJS.enc.Utf8);
        return JSON.parse(decrypted);
    } catch {
        return undefined;

function saveToSessionStorage(state) {
        try {
            const serializedState = JSON.stringify(state);
            const encrypted = CryptoJS.AES.encrypt(serializedState, key, {iv: iv});
            sessionStorage.setItem('state', encrypted)
        } catch (e) {

        <Provider store={store}>

store.subscribe(() => saveToSessionStorage(store.getState()));


jQuery AJAX Call to PHP Script with JSON Return

Make it dataType instead of datatype.

And add below code in php as your ajax request is expecting json and will not accept anything, but json.

header('Content-Type: application/json');

Correct Content type for JSON and JSONP

The response visible in firebug is text data. Check Content-Type of the response header to verify, if the response is json. It should be application/json for dataType:'json' and text/html for dataType:'html'.

How do you find the row count for all your tables in Postgres

If you're in the psql shell, using \gexec allows you to execute the syntax described in syed's answer and Aur's answer without manual edits in an external text editor.

with x (y) as (
        'select count(*), '''||
        ''' as "tablename" from '||
        tablename||' '
    from pg_tables
    where schemaname='public'
    string_agg(y,' union all '||chr(10)) || ' order by tablename'
from x \gexec

Note, string_agg() is used both to delimit union all between statements and to smush the separated datarows into a single unit to be passed into the buffer.


Sends the current query buffer to the server, then treats each column of each row of the query's output (if any) as a SQL statement to be executed.

How to check if a double is null?

How are you getting the value of "results"? Are you getting it via ResultSet.getDouble()? In that case, you can check ResultSet.wasNull().

How can I print out all possible letter combinations a given phone number can represent?

This is the C# port of this answer.


public class LetterCombinations
    private static readonly Dictionary<string, string> Representations = new Dictionary<string, string>
       {"2", "abc" },
       {"3", "def" },
       {"4", "ghi" },
       {"5", "jkl" },
       {"6", "mno" },
       {"7", "pqrs" },
       {"8", "tuv" },
       {"9", "wxyz" },

    public static List<string> FromPhoneNumber(string phoneNumber)
        var result = new List<string> { string.Empty };

        // go through each number in the phone
        for (int i = 0; i < phoneNumber.Length; i++)
            var pre = new List<string>();
            foreach (var str in result)
                var letters = Representations[phoneNumber[i].ToString()];
                // go through each representation of the number
                for (int j = 0; j < letters.Length; j++)
                    pre.Add(str + letters[j]);
            result = pre;

        return result;

Unit Tests

public class UnitTest
    public void One_Digit_Yields_Three_Representations()
        var sut = "2";

        var expected = new List<string>{ "a", "b", "c" };
        var actualResults = LetterCombinations.FromPhoneNumber(sut);

        CollectionAssert.AreEqual(expected, actualResults);

    public void Two_Digits_Yield_Nine_Representations()
        var sut = "22";

        var expected = new List<string> { "aa", "ab", "ac", "ba", "bb", "bc", "ca", "cb", "cc" };
        var actualResults = LetterCombinations.FromPhoneNumber(sut);

        CollectionAssert.AreEqual(expected, actualResults);

    public void Three_Digits_Yield_ThirtyNine_Representations()
        var sut = "222";

        var actualResults = LetterCombinations.FromPhoneNumber(sut);

        var possibleCombinations = Math.Pow(3,3); //27

        Assert.AreEqual(possibleCombinations, actualResults.Count);

How to create a css rule for all elements except one class?

Wouldn't setting a css rule for all tables, and then a subsequent one for tables where class="dojoxGrid" work? Or am I missing something?

Print commit message of a given commit in git

git show is more a plumbing command than git log, and has the same formatting options:

git show -s --format=%B SHA1

How can I copy a file on Unix using C?

Copying files byte-by-byte does work, but is slow and wasteful on modern UNIXes. Modern UNIXes have “copy-on-write” support built-in to the filesystem: a system call makes a new directory entry pointing at the existing bytes on disk, and no file content bytes on disk are touched until one of the copies is modified, at which point only the changed blocks are written to disk. This allows near-instant file copies that use no additional file blocks, regardless of file size. For example, here are some details about how this works in xfs.

On linux, use the FICLONE ioctl as coreutils cp now does by default.

 #ifdef FICLONE
   return ioctl (dest_fd, FICLONE, src_fd);
   errno = ENOTSUP;
   return -1;

On macOS, use clonefile(2) for instant copies on APFS volumes. This is what Apple’s cp -c uses. The docs are not completely clear but it is likely that copyfile(3) with COPYFILE_CLONE also uses this. Leave a comment if you’d like me to test that.

In case these copy-on-write operations are not supported—whether the OS is too old, the underlying file system does not support it, or because you are copying files between different filesystems—you do need to fall back to trying sendfile, or as a last resort, copying byte-by-byte. But to save everyone a lot of time and disk space, please give FICLONE and clonefile(2) a try first.

How to merge lists into a list of tuples?

You can use map lambda

a = [2,3,4]
b = [5,6,7]
c = map(lambda x,y:(x,y),a,b)

This will also work if there lengths of original lists do not match

How to add a default "Select" option to this ASP.NET DropDownList control?

If you want to make the first item unselectable, try this:

DropDownList1.Items.Insert(0, new ListItem("Select", "-1"));
DropDownList1.Items[0].Attributes.Add("disabled", "disabled");

Convert String to Calendar Object in Java

Yes it would be bad practice to parse it yourself. Take a look at SimpleDateFormat, it will turn the String into a Date and you can set the Date into a Calendar instance.

Eclipse: stop code from running (java)

The easiest way to do this is to click on the Terminate button(red square) in the console:

enter image description here

ASP.NET Web Site or ASP.NET Web Application?

There is an article in MSDN which describes the differences:

Comparing Web Site Projects and Web Application Projects

BTW: there are some similar questions about that topic, e.g:

How to configure log4j to only keep log files for the last seven days?

According to the following post, you can't do this with log4j: Use MaxBackupIndex in DailyRollingFileAppender -log4j

As far as I know, this functionality was supposed to make it into log4j 2.0 but that effort got sidetracked. According to the logback website, logback is the intended successor to log4j so you might consider using that.

There's an API called SLF4J which provides a common API to logging. It will load up the actual logging implementation at runtime so depending on the configuration that you have provided, it might use java.util.log or log4j or logback or any other library capable of providing logging facilities. There'll be a bit of up-front work to go from using log4j directly to using SLF4J but they provide some tools to automate this process. Once you've converted your code to use SLF4J, switching logging backends should simply be a case of changing the config file.

Reverse for '*' with arguments '()' and keyword arguments '{}' not found

In case it helps someone, I had a similar issue and the error was because of two reasons:

  1. Not using the app's namespace before the url name

    {% url 'app_name:url_name' %}
  2. Missing single quotes around the url name (as pointed out here by Charlie)

How to enable production mode?

You enable it by importing and executing the function (before calling bootstrap):

import {enableProdMode} from '@angular/core';


But this error is indicator that something is wrong with your bindings, so you shouldn't just dismiss it, but try to figure out why it's happening.

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

I had the same issue. I found this.

ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’

This is because you are not running the mysqld daemon before launching the MySQL client. The file /var/lib/mysql/mysql.sock will be automatically created upon running the first instance of MySQL.

To fix:

First start the MySQL daemon, then type mysql:

/etc/init.d/mysqld start

Changing MySQL Root Password

By default, the root password is empty for the MySQL database. It is a good idea to change the MySQL root password to a new one from a security point of view.

mysql> USE mysql;
mysql> UPDATE user SET Password=PASSWORD('newpassword') WHERE user='root';

Once done, check by logging in:

mysql -u root -p
Enter Password: <your new password>

CSS background image to fit height, width should auto-scale in proportion


.something { 
    background: url(images/bg.jpg) no-repeat center center fixed; 
    width: 100%;
    height: 100%;
    position: fixed;
    top: 0;
    left: 0;
    z-index: -100;  

How can I get the order ID in WooCommerce?

This is quite an old question now, but someone may come here looking for an answer:

echo $order->id;

This should return the order id without "#".

EDIT (feb/2018)

The current way of accomplishing this is by using:


How can I pass parameters to a partial view in mvc 4

For Asp.Net core you better use

<partial name="_MyPartialView" model="MyModel" />

So for example

@foreach (var item in Model)
   <partial name="_MyItemView" model="item" />

How to sum all column values in multi-dimensional array?

It can also be done using array_walk:

function array_sum_values(array $input, $key) {
   $sum = 0;
   array_walk($input, function($item, $index, $params) {
         if (!empty($item[$params[1]]))
            $params[0] += $item[$params[1]];
      }, array(&$sum, $key)
   return $sum;

var_dump(array_sum_values($arr, 'gozhi'));

Not so readable like previous solutions but it works :)

How to stop and restart memcached server?

If you want to be allowed to shutdown the memcached server you can give it that option before start it :

memcached -A &

With this option when you connect to memcached server for example:

telnet localhost 11211

then you can use shutdown command to shutdown the server. You can also shutdown the memcached server when it is run as a process, first find the process PID using:

pidof memcached

then use:

kill PID command

Get raw POST body in Python Flask regardless of Content-Type header

Use request.get_data() to get the raw data, regardless of content type. The data is cached and you can subsequently access, request.json, request.form at will.

If you access first, it will call get_data with an argument to parse form data first. If the request has a form content type (multipart/form-data, application/x-www-form-urlencoded, or application/x-url-encoded) then the raw data will be consumed. and request.json will appear empty in this case.

"if not exist" command in batch file

When testing for directories remember that every directory contains two special files.

One is called '.' and the other '..'

. is the directory's own name while .. is the name of it's parent directory.

To avoid trailing backslash problems just test to see if the directory knows it's own name.


if not exist %temp%\buffer\. mkdir %temp%\buffer

Is there a way to create multiline comments in Python?

From the accepted answer...

You can use triple-quoted strings. When they're not a docstring (first thing in a class/function/module), they are ignored.

This is simply not true. Unlike comments, triple-quoted strings are still parsed and must be syntactically valid, regardless of where they appear in the source code.

If you try to run this code...

def parse_token(token):
    This function parses a token.
    TODO: write a decent docstring :-)

    if token == '\\and':

    elif token == '\\or':

    elif token == '\\xor':
        Note that we still need to provide support for the deprecated
        token \xor. Hopefully we can drop support in libfoo 2.0.

        raise ValueError

You'll get either...

ValueError: invalid \x escape

...on Python 2.x or...

SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 79-80: truncated \xXX escape

...on Python 3.x.

The only way to do multi-line comments which are ignored by the parser is...

elif token == '\\xor':
    # Note that we still need to provide support for the deprecated
    # token \xor. Hopefully we can drop support in libfoo 2.0.

How to add include and lib paths to configure/make cycle?

This took a while to get right. I had this issue when cross-compiling in Ubuntu for an ARM target. I solved it with:

PATH=$PATH:/ccpath/bin CC=ccname-gcc AR=ccname-ar LD=ccname-ld CPPFLAGS="-nostdinc -I/ccrootfs/usr/include ..." LDFLAGS=-L/ccrootfs/usr/lib ./ --build=`config.guess` --host=armv5tejl-unknown-linux-gnueabihf

Notice CFLAGS is not used with, using it gave me the error: "configure: error: C compiler cannot create executables". In the build environment I was using an script was provided, if you don't have an script substitute ./ with ./configure in the command above. I ran config.guess on the target system to get the --host parameter.

After successfully running, compile with:

PATH=$PATH:/ccpath/bin CC=ccname-gcc AR=ccname-ar LD=ccname-ld CPPFLAGS="-nostdinc -I/ccrootfs/usr/include ..." LDFLAGS=-L/ccrootfs/usr/lib CFLAGS="-march=... -mcpu=... etc." make

The CFLAGS I chose to use were: "-march=armv5te -fno-tree-vectorize -mthumb-interwork -mcpu=arm926ej-s". It will take a while to get all of the include directories set up correctly: you might want some includes pointing to your cross-compiler and some pointing to your root file system includes, and there will likely be some conflicts.

I'm sure this is not the perfect answer. And I am still seeing some include directories pointing to / and not /ccrootfs in the Makefiles. Would love to know how to correct this. Hope this helps someone.

How to list all installed packages and their versions in Python?

If this is needed to run from within python you can just invoke subprocess

from subprocess import PIPE, Popen

pip_process = Popen(["pip freeze"], stdout=PIPE,
                   stderr=PIPE, shell=True)
stdout, stderr = pip_process.communicate()

How to Import Excel file into mysql Database from PHP

For >= 2nd row values insert into table-

$file = fopen($filename, "r");
//$sql_data = "SELECT * FROM prod_list_1 ";

$count = 0;                                         // add this line
while (($emapData = fgetcsv($file, 10000, ",")) !== FALSE)
    $count++;                                      // add this line

    if($count>1){                                  // add this line
      $sql = "INSERT into prod_list_1(p_bench,p_name,p_price,p_reason) values ('$emapData[0]','$emapData[1]','$emapData[2]','$emapData[3]')";
    }                                              // add this line

Looping from 1 to infinity in Python

Simplest and best:

i = 0
while not there_is_reason_to_break(i):
    # some code here
    i += 1

It may be tempting to choose the closest analogy to the C code possible in Python:

from itertools import count

for i in count():
    if thereIsAReasonToBreak(i):

But beware, modifying i will not affect the flow of the loop as it would in C. Therefore, using a while loop is actually a more appropriate choice for porting that C code to Python.

How to "Open" and "Save" using java

You want to use a JFileChooser object. It will open and be modal, and block in the thread that opened it until you choose a file.


JFileChooser fileChooser = new JFileChooser();
if (fileChooser.showOpenDialog(modalToComponent) == JFileChooser.APPROVE_OPTION) {
  File file = fileChooser.getSelectedFile();
  // load from file


JFileChooser fileChooser = new JFileChooser();
if (fileChooser.showSaveDialog(modalToComponent) == JFileChooser.APPROVE_OPTION) {
  File file = fileChooser.getSelectedFile();
  // save to file

There are more options you can set to set the file name extension filter, or the current directory. See the API for the javax.swing.JFileChooser for details. There is also a page for "How to Use File Choosers" on Oracle's site:

How to make div occupy remaining height?

Use absolute positioning:

    width: 100%;_x000D_
    height: 50px;_x000D_
    background-color:red;/*Development Only*/_x000D_
    width: 100%;_x000D_
    position: absolute;_x000D_
    top: 50px;_x000D_
    bottom: 0;_x000D_
    background-color:blue;/*Development Only*/_x000D_
<div id="div1"></div>_x000D_
<div id="div2"></div>

In C++ check if std::vector<string> contains a certain value

it's in <algorithm> and called std::find.

How can bcrypt have built-in salts?

This is bcrypt:

Generate a random salt. A "cost" factor has been pre-configured. Collect a password.

Derive an encryption key from the password using the salt and cost factor. Use it to encrypt a well-known string. Store the cost, salt, and cipher text. Because these three elements have a known length, it's easy to concatenate them and store them in a single field, yet be able to split them apart later.

When someone tries to authenticate, retrieve the stored cost and salt. Derive a key from the input password, cost and salt. Encrypt the same well-known string. If the generated cipher text matches the stored cipher text, the password is a match.

Bcrypt operates in a very similar manner to more traditional schemes based on algorithms like PBKDF2. The main difference is its use of a derived key to encrypt known plain text; other schemes (reasonably) assume the key derivation function is irreversible, and store the derived key directly.

Stored in the database, a bcrypt "hash" might look something like this:


This is actually three fields, delimited by "$":

  • 2a identifies the bcrypt algorithm version that was used.
  • 10 is the cost factor; 210 iterations of the key derivation function are used (which is not enough, by the way. I'd recommend a cost of 12 or more.)
  • vI8aWBnW3fID.ZQ4/zo1G.q1lRps.9cGLcZEiGDMVr5yUP1KUOYTa is the salt and the cipher text, concatenated and encoded in a modified Base-64. The first 22 characters decode to a 16-byte value for the salt. The remaining characters are cipher text to be compared for authentication.

This example is taken from the documentation for Coda Hale's ruby implementation.

How do you split a list into evenly sized chunks?

A generic chunker for any iterable, which gives the user a choice of how to handle a partial chunk at the end.

Tested on Python 3.

from enum import Enum

class PartialChunkOptions(Enum):
    INCLUDE = 0
    EXCLUDE = 1
    PAD = 2
    ERROR = 3

class PartialChunkException(Exception):

def chunker(iterable, n, on_partial=PartialChunkOptions.INCLUDE, pad=None):
    A chunker yielding n-element lists from an iterable, with various options
    about what to do about a partial chunk at the end.

    on_partial=PartialChunkOptions.INCLUDE (the default):
                     include the partial chunk as a short (<n) element list

                     do not include the partial chunk

                     pad to an n-element list 
                     (also pass pad=<pad_value>, default None)

                     raise a RuntimeError if a partial chunk is encountered

    on_partial = PartialChunkOptions(on_partial)        

    iterator = iter(iterable)
    while True:
        vals = []
        for i in range(n):
            except StopIteration:
                if vals:
                    if on_partial == PartialChunkOptions.INCLUDE:
                        yield vals
                    elif on_partial == PartialChunkOptions.EXCLUDE:
                    elif on_partial == PartialChunkOptions.PAD:
                        yield vals + [pad] * (n - len(vals))
                    elif on_partial == PartialChunkOptions.ERROR:
                        raise PartialChunkException
        yield vals

import chunker

chunk_size = 3

for it in (range(100, 107),
          range(100, 109)):

    print("\nITERABLE TO CHUNK: {}".format(it))
    print("CHUNK SIZE: {}".format(chunk_size))

    for option in chunker.PartialChunkOptions.__members__.values():
        print("\noption {} used".format(option))
            for chunk in chunker.chunker(it, chunk_size, on_partial=option):
        except chunker.PartialChunkException:
            print("PartialChunkException was raised")

output of

ITERABLE TO CHUNK: range(100, 107)

option PartialChunkOptions.INCLUDE used
[100, 101, 102]
[103, 104, 105]

option PartialChunkOptions.EXCLUDE used
[100, 101, 102]
[103, 104, 105]

option PartialChunkOptions.PAD used
[100, 101, 102]
[103, 104, 105]
[106, None, None]

option PartialChunkOptions.ERROR used
[100, 101, 102]
[103, 104, 105]
PartialChunkException was raised

ITERABLE TO CHUNK: range(100, 109)

option PartialChunkOptions.INCLUDE used
[100, 101, 102]
[103, 104, 105]
[106, 107, 108]

option PartialChunkOptions.EXCLUDE used
[100, 101, 102]
[103, 104, 105]
[106, 107, 108]

option PartialChunkOptions.PAD used
[100, 101, 102]
[103, 104, 105]
[106, 107, 108]

option PartialChunkOptions.ERROR used
[100, 101, 102]
[103, 104, 105]
[106, 107, 108]

How to access nested elements of json object using getJSONArray method

I suggest you to use Gson library. It allows to parse JSON string into object data model. Please, see my example:

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;


public class GsonProgram {

    public static void main(String... args) {
        String response = "{\"result\":{\"map\":{\"entry\":[{\"key\":{\"@xsi.type\":\"xs:string\",\"$\":\"ContentA\"},\"value\":\"fsdf\"},{\"key\":{\"@xsi.type\":\"xs:string\",\"$\":\"ContentB\"},\"value\":\"dfdf\"}]}}}";

        Gson gson = new GsonBuilder().serializeNulls().create();
        Response res = gson.fromJson(response, Response.class);

        System.out.println("Entries: " + res.getResult().getMap().getEntry());

class Response {

    private Result result;

    public Result getResult() {
        return result;

    public void setResult(Result result) {
        this.result = result;

    public String toString() {
        return result.toString();

class Result {

    private MapNode map;

    public MapNode getMap() {
        return map;

    public void setMap(MapNode map) { = map;

    public String toString() {
        return map.toString();

class MapNode {

    List<Entry> entry = new ArrayList<Entry>();

    public List<Entry> getEntry() {
        return entry;

    public void setEntry(List<Entry> entry) {
        this.entry = entry;

    public String toString() {
        return Arrays.toString(entry.toArray());

class Entry {

    private Key key;
    private String value;

    public String getValue() {
        return value;

    public void setValue(String value) {
        this.value = value;

    public Key getKey() {
        return key;

    public void setKey(Key key) {
        this.key = key;

    public String toString() {
        return "[key=" + key + ", value=" + value + "]";

class Key {

    private String value;

    private String type;

    public String getValue() {
        return value;

    public void setValue(String value) {
        this.value = value;

    public String getType() {
        return type;

    public void setType(String type) {
        this.type = type;

    public String toString() {
        return "[value=" + value + ", type=" + type + "]";

Program output:

Entries: [[key=[value=ContentA, type=xs:string], value=fsdf], [key=[value=ContentB, type=xs:string], value=dfdf]]

If you not familiar with this library, then you can find a lot of informations in "Gson User Guide".

Java - Getting Data from MySQL database

Here you go :

Connection con = DriverManager.getConnection("jdbc:mysql://localhost/t", "", "");

Statement st = con.createStatement();
String sql = ("SELECT * FROM posts ORDER BY id DESC LIMIT 1;");
ResultSet rs = st.executeQuery(sql);
if( { 
 int id = rs.getInt("first_column_name"); 
 String str1 = rs.getString("second_column_name");


In rs.getInt or rs.getString you can pass column_id starting from 1, but i prefer to pass column_name as its more informative as you don't have to look at database table for which index is what column.


boolean next() throws SQLException

Moves the cursor froward one row from its current position. A ResultSet cursor is initially positioned before the first row; the first call to the method next makes the first row the current row; the second call makes the second row the current row, and so on.

When a call to the next method returns false, the cursor is positioned after the last row. Any invocation of a ResultSet method which requires a current row will result in a SQLException being thrown. If the result set type is TYPE_FORWARD_ONLY, it is vendor specified whether their JDBC driver implementation will return false or throw an SQLException on a subsequent call to next.

If an input stream is open for the current row, a call to the method next will implicitly close it. A ResultSet object's warning chain is cleared when a new row is read.

Returns: true if the new current row is valid; false if there are no more rows Throws: SQLException - if a database access error occurs or this method is called on a closed result set


Difference between getContext() , getApplicationContext() , getBaseContext() and "this"

Context provides information about the Actvity or Application to newly created components.

Relevant Context should be provided to newly created components (whether application context or activity context)

Since Activity is a subclass of Context, one can use this to get that activity's context

jQuery Validation plugin: disable validation for specified submit buttons

You can add a CSS class of cancel to a submit button to suppress the validation


<input class="cancel" type="submit" value="Save" />

See the jQuery Validator documentation of this feature here: Skipping validation on submit


The above technique has been deprecated and replaced with the formnovalidate attribute.

<input formnovalidate="formnovalidate" type="submit" value="Save" />

Are there any disadvantages to always using nvarchar(MAX)?

Based on the link provided in the accepted answer it appears that:

  1. 100 characters stored in an nvarchar(MAX) field will be stored no different to 100 characters in an nvarchar(100) field - the data will be stored inline and you will not have the overhead of reading and writing data 'out of row'. So no worries there.

  2. If the size is greater than 4000 the data would be stored 'out of row' automatically, which is what you would want. So no worries there either.


  1. You cannot create an index on an nvarchar(MAX) column. You can use full-text indexing, but you cannot create an index on the column to improve query performance. For me, this seals the is a definite disadvantage to always use nvarchar(MAX).


If you want a kind of "universal string length" throughout your whole database, which can be indexed and which will not waste space and access time, then you could use nvarchar(4000).

How to open Visual Studio Code from the command line on OSX?

I ran: open -a "Visual Studio Code" [folder-name] to open a folder with my Visual Studio Code application. Folder name is optional if you just want to open the application. Not sure if this is exactly your use-case, but hope this helps!

Android:java.lang.OutOfMemoryError: Failed to allocate a 23970828 byte allocation with 2097152 free bytes and 2MB until OOM

Actually you can add in your manifest these lines android:hardwareAccelerated="false" , android:largeHeap="true" it is working for some situations, but be aware that the other part of code can be arguing with this.


System.Net.WebException HTTP status code

By using the null-conditional operator (?.) you can get the HTTP status code with a single line of code:

 HttpStatusCode? status = (ex.Response as HttpWebResponse)?.StatusCode;

The variable status will contain the HttpStatusCode. When the there is a more general failure like a network error where no HTTP status code is ever sent then status will be null. In that case you can inspect ex.Status to get the WebExceptionStatus.

If you just want a descriptive string to log in case of a failure you can use the null-coalescing operator (??) to get the relevant error:

string status = (ex.Response as HttpWebResponse)?.StatusCode.ToString()
    ?? ex.Status.ToString();

If the exception is thrown as a result of a 404 HTTP status code the string will contain "NotFound". On the other hand, if the server is offline the string will contain "ConnectFailure" and so on.

(And for anybody that wants to know how to get the HTTP substatus code. That is not possible. It is a Microsoft IIS concept that is only logged on the server and never sent to the client.)

Android SQLite Example

Using Helper class you can access SQLite Database and can perform the various operations on it by overriding the onCreate() and onUpgrade() methods.

Python 3 - Encode/Decode vs Bytes/Str

To add to Lennart Regebro's answer There is even the third way that can be used:

encoded3 = str.encode(original, 'utf-8')

Anyway, it is actually exactly the same as the first approach. It may also look that the second way is a syntactic sugar for the third approach.

A programming language is a means to express abstract ideas formally, to be executed by the machine. A programming language is considered good if it contains constructs that one needs. Python is a hybrid language -- i.e. more natural and more versatile than pure OO or pure procedural languages. Sometimes functions are more appropriate than the object methods, sometimes the reverse is true. It depends on mental picture of the solved problem.

Anyway, the feature mentioned in the question is probably a by-product of the language implementation/design. In my opinion, this is a nice example that show the alternative thinking about technically the same thing.

In other words, calling an object method means thinking in terms "let the object gives me the wanted result". Calling a function as the alternative means "let the outer code processes the passed argument and extracts the wanted value".

The first approach emphasizes the ability of the object to do the task on its own, the second approach emphasizes the ability of an separate algoritm to extract the data. Sometimes, the separate code may be that much special that it is not wise to add it as a general method to the class of the object.

Extract public/private key from PKCS12 file for later use in SSH-PK-Authentication

Update: I noticed that my answer was just a poor duplicate of a well explained question on by BryKKan

Here is an extract from it:

openssl pkcs12 -in <filename.pfx> -nocerts -nodes | sed -ne '/-BEGIN PRIVATE KEY-/,/-END PRIVATE KEY-/p' > <clientcert.key>

openssl pkcs12 -in <filename.pfx> -clcerts -nokeys | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > <clientcert.cer>

openssl pkcs12 -in <filename.pfx> -cacerts -nokeys -chain | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > <cacerts.cer>

How to clear a data grid view

If it's bound to a datasource -


Worked for me.

Android ImageView Fixing Image Size

Fix ImageView's size with dp or fill_parent and set android:scaleType to fitXY.

EOFException - how to handle?

While reading from the file, your are not terminating your loop. So its read all the values and correctly throws EOFException on the next iteration of the read at line below:

 price = in.readDouble();

If you read the documentation, it says:


EOFException - if this input stream reaches the end before reading eight bytes.

IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.

Put a proper termination condition in your while loop to resolve the issue e.g. below:

     while(in.available() > 0)  <--- if there are still bytes to read

How to Add Incremental Numbers to a New Column Using Pandas

For a pandas DataFrame whose index starts at 0 and increments by 1 (i.e., the default values) you can just do:

df.insert(0, 'New_ID', df.index + 880)

if you want New_ID to be the first column. Otherwise this if you don't mind it being at the end:

df['New_ID'] = df.index + 880

Is there an equivalent of lsusb for OS X

At least on 10.10.5, system_profiler SPUSBDataType output is NOT dynamically updated when a new USB device gets plugged in, while ioreg -p IOUSB -l -w 0 does.

How to run SQL in shell script

You can use a heredoc. e.g. from a prompt:

$ sqlplus -s username/password@oracle_instance <<EOF
set feed off
set pages 0
select count(*) from table;

so sqlplus will consume everything up to the EOF marker as stdin.

The type must be a reference type in order to use it as parameter 'T' in the generic type or method

I can't repro, but I suspect that in your actual code there is a constraint somewhere that T : class - you need to propagate that to make the compiler happy, for example (hard to say for sure without a repro example):

public class Derived<SomeModel> : Base<SomeModel> where SomeModel : class, IModel
                                                                 see this bit

Bootstrap 3 Carousel fading to new slide instead of sliding to new slide

In reply to gerardnll's answer the Less code to extend Bootstrap 3.3.x carousel by fade effect:

// Carousel Fade effect
// --------------------------------------------------

// inspired from
.carousel-fade {

    .carousel-inner {
        .item {

        .active {

            &.right {
                left: 0;
                z-index: 1;

        .prev.right {

    .carousel-control {
        z-index: 2;

// WHAT IS NEW IN 3.3: 
// "Added transforms to improve carousel performance in modern browsers."
// now override the 3.3 new styles for modern browsers & apply opacity
@media all and (transform-3d), (-webkit-transform-3d) {

    .carousel-fade {

        .carousel-inner {

            > .item {
                &.active.left {
                    .translate3d(0; 0; 0);

                &.active {
                    .translate3d(0; 0; 0);




The only thing is the transition duration which is not working as expected when longer than .8s (around). Maybe someone has a solution to solve this strange behaviour.

Note: The LESS code has .transition-duration(.8s); commented, so the default carousel transition duration is used. You can play with the value and see the effect. Longer duration (> 0.8) renders the fade effect less smooth.

Java: how do I check if a Date is within a certain range?

That's the correct way. Calendars work the same way. The best I could offer you (based on your example) is this:

boolean isWithinRange(Date testDate) {
    return testDate.getTime() >= startDate.getTime() &&
             testDate.getTime() <= endDate.getTime();

Date.getTime() returns the number of milliseconds since 1/1/1970 00:00:00 GMT, and is a long so it's easily comparable.

How to hide image broken Icon using only CSS/HTML?

If you will add alt with text alt="abc" it will show the show corrupt thumbnail, and alt message abc

<img src="pic_trulli.jpg" alt="abc"/>


If you will not add alt it will show the show corrupt thumbnail

<img src="pic_trulli.jpg"/>


If you want to hide the broken one just add alt="" it will not show corrupt thumbnail and any alt message(without using js)

<img src="pic_trulli.jpg" alt=""/>

If you want to hide the broken one just add alt="" & onerror="'none'" it will not show corrupt thumbnail and any alt message(with js)

<img src="pic_trulli.jpg" alt="abc" onerror="'none'"/>

4th one is a little dangerous(not exactly) , if you want to add any image in onerror event, it will not display even if Image exist as style.display is like adding. So, use it when you don't require any alternative image to display.

display: 'none'; // in css

If we give it in CSS, then the item will not display(like image, iframe, div like that).

If you want to display image & you want to display totally blank space if error, then you can use, but also be careful this will not take any space. So, you need to keep it in a div may be


What is the most accurate way to retrieve a user's correct IP address in PHP?

As someone said previously, the key here is for what reason you want to store user's ips.

I'll give an example from a registration system I work on and of course the solution just to contribute sth in this old discussion that comes frequently in my searches.

Many php registration libraries use ip to throttle/lock out failed attempts based on user's ip. Consider this table:

-- mysql
CREATE TABLE `attempts` (
  `ip` varchar(39) NOT NULL, /*<<=====*/
  `expiredate` datetime NOT NULL,
  PRIMARY KEY (`id`)
 -- sqlite

Then, when a user tries to do a login or anything related with servicing like a password reset, a function is called at the start:

public function isBlocked() {
       * used one of the above methods to capture user's ip!!!
      $ip = $this->ip;
      // delete attempts from this ip with 'expiredate' in the past
      $this->deleteAttempts($ip, false);
      $query = $this->dbh->prepare("SELECT count(*) FROM {$this->token->get('table_attempts')} WHERE ip = ?");
      $attempts = $query->fetchColumn();
      if ($attempts < intval($this->token->get('attempts_before_verify'))) {
         return "allow";
      if ($attempts < intval($this->token->get('attempts_before_ban'))) {
         return "captcha";
      return "block";

Say, for example, $this->token->get('attempts_before_ban') === 10 and 2 users come for the same ips as is the case in the previous codes where headers can be spoofed, then after 5 attempts each both are banned! Even worst, if all come from the same proxy then only the first 10 users will be logged and all the rest will be banned!

The critical here is that we need a unique index on table attempts and we can get it from a combination like:

 `ip` varchar(39) NOT NULL,
 `jwt_load varchar(100) NOT NULL

where jwt_load comes from a http cookie that follows the json web token technology where we store only the encrypted payload that should contain an arbitrary/unique value for every user. Of course the request should be modified to: "SELECT count(*) FROM {$this->token->get('table_attempts')} WHERE ip = ? AND jwt_load = ?" and the class should also initiate a private $jwt.

How to get calendar Quarter from a date in TSQL

I did it like this (I am using SQL Server):

SELECT 'Q' + cast(DATEPART(QUARTER, GETDATE()) as varchar(1)) + ' - ' + cast(DATEPART(YEAR, GETDATE()) as varchar(4)) AS 'Date Quarter'

multiple conditions for JavaScript .includes() method

Extending String native prototype:

if (!String.prototype.contains) {
    Object.defineProperty(String.prototype, 'contains', {
        value(patterns) {
            if (!Array.isArray(patterns)) {
                return false;

            let value = 0;
            for (let i = 0; i < patterns.length; i++) {
                const pattern = patterns[i];
                value = value + this.includes(pattern);
            return (value === 1);

Allowing you to do things like:

console.log('Hi, hope you like this option'.toLowerCase().contains(["hello", "hi", "howdy"])); // True

How do you exit from a void function in C++?

Use a return statement!



if (condition) return;

You don't need to (and can't) specify any values, if your method returns void.

Extracting the top 5 maximum values in excel


Type this formula in first row of your sheet then drag down till fifth row...

its a simple vlookup, which finds the large value in array (A1:A10), the ROW() function gives the row number (first row = 1, second row =2 and so on) and further is the lookup criteria.

Note: You can replace the ROW() to 1,2,3,4,5 as requried...if you have this formula in other than the 1st row, then make sure you subtract some numbers from the row() to get accurate results.

EDIT: TO check tie results

This is possible, you need to add a helper column to the sheet, here is the link. Do let me know in case things seems to be messy....

Dynamic SELECT TOP @var In SQL Server

Or you just put the variable in parenthesis

DECLARE @top INT = 10;

FROM <table_name>;

IIS7: A process serving application pool 'YYYYY' suffered a fatal communication error with the Windows Process Activation Service

When I had this problem, I installed 'Remote Tools for Visual Studio 2015' from MSDN. I attached my local VS to the server to debug.

I appreciate that some folks may not have the ability to either install on or access other servers, but I thought I'd throw it out there as an option.

How to convert seconds to HH:mm:ss in moment.js

Until 24 hrs. As Duration.format is deprecated, with [email protected]

const seconds = 123;

Oracle SQL : timestamps in where clause


You need to use to_timestamp() to convert your string to a proper timestamp value:

to_timestamp('12-01-2012 21:24:00', 'dd-mm-yyyy hh24:mi:ss')


If your column is of type DATE (which also supports seconds), you need to use to_date()

to_date('12-01-2012 21:24:00', 'dd-mm-yyyy hh24:mi:ss')


To get this into a where condition use the following:

select * 
from TableA 
where startdate >= to_timestamp('12-01-2012 21:24:00', 'dd-mm-yyyy hh24:mi:ss')
  and startdate <= to_timestamp('12-01-2012 21:25:33', 'dd-mm-yyyy hh24:mi:ss')


You never need to use to_timestamp() on a column that is of type timestamp.

Console.WriteLine and generic List

        List<int> a = new List<int>() { 1, 2, 3, 4, 5 };
        a.ForEach(p => Console.WriteLine(p));

edit: ahhh he beat me to it.

How can I remove the extension of a filename in a shell script?

You should be using the command substitution syntax $(command) when you want to execute a command in script/command.

So your line would be

name=$(echo "$filename" | cut -f 1 -d '.')

Code explanation:

  1. echo get the value of the variable $filename and send it to standard output
  2. We then grab the output and pipe it to the cut command
  3. The cut will use the . as delimiter (also known as separator) for cutting the string into segments and by -f we select which segment we want to have in output
  4. Then the $() command substitution will get the output and return its value
  5. The returned value will be assigned to the variable named name

Note that this gives the portion of the variable up to the first period .:

$ echo "$filename" | cut -f 1 -d '.'
$ filename=hello.hello.hello
$ echo "$filename" | cut -f 1 -d '.'
$ filename=hello
$ echo "$filename" | cut -f 1 -d '.'

Java/ JUnit - AssertTrue vs AssertFalse

Your understanding is incorrect, in cases like these always consult the JavaDoc.


public static void assertFalse(java.lang.String message,
                               boolean condition)

Asserts that a condition is false. If it isn't it throws an AssertionError with the given message.


  • message - the identifying message for the AssertionError (null okay)
  • condition - condition to be checked

JBoss AS 7: How to clean up tmp?

I do not have experience with version 7 of JBoss but with 5 I often had issues when redeploying apps which went away when I cleaned the work and tmp folder. I wrote a script for that which was executed everytime the server shut down. Maybe executing it before startup is better considering abnormal shutdowns (which weren't uncommon with Jboss 5 :))

How to include file in a bash shell script

Yes, use source or the short form which is just .:


Toggle display:none style with JavaScript

You can do this through straight javascript and DOM, but I really recommend learning JQuery. Here is a function you can use to actually toggle that object.

EDIT: Adding the actual code:


HTML snippet:

<a href="#" id="showAll" title="Show Tags">Show All Tags</a>
<ul id="tags" class="subforums" style="display:none;overflow-x: visible; overflow-y: visible; ">
    <li>Tag 1</li>
    <li>Tag 2</li>
    <li>Tag 3</li>
    <li>Tag 4</li>
    <li>Tag 5</li>

Javascript code using JQuery from Google's Content Distribution Network:

$(function() {
    $('#showAll').click(function(){  //Adds click event listener  
        $('#tags').toggle('slow'); // Toggles visibility.  Use the 'slow' parameter to add a nice effect.

You can test directly from this link:

Additional Comments on JQuery:

Someone has suggested that using JQuery for something like this is wrong because it is a 50k Library. I have a strong opinion against that.

JQuery is widely used because of the huge advantages it offers (like many other javascript frameworks). Additionally, JQuery is hosted by Content Distribution Networks (CDNs) like Google's CDN that will guarantee that the library is cached in the client's browser. It will have minimal impact on the client.

Additionally, with JQuery you can use powerful selectors, adding event listener, and use functions that are for the most part guaranteed to be cross-browser.

If you are a beginner and want to learn Javascript, please don't discount frameworks like JQuery. It will make your life so much easier.

adding directory to sys.path /PYTHONPATH

This is working as documented. Any paths specified in PYTHONPATH are documented as normally coming after the working directory but before the standard interpreter-supplied paths. sys.path.append() appends to the existing path. See here and here. If you want a particular directory to come first, simply insert it at the head of sys.path:

import sys

That said, there are usually better ways to manage imports than either using PYTHONPATH or manipulating sys.path directly. See, for example, the answers to this question.

Using AngularJS date filter with UTC date

You have also the possibility to write a custom filter for your date, that display it in UTC format. Note that I used toUTCString().

var app = angular.module('myApp', []);_x000D_
app.controller('dateCtrl', function($scope) {_x000D_
    $ = new Date();_x000D_
app.filter('utcDate', function() {_x000D_
    return function(input) {_x000D_
       return input.toUTCString();_x000D_
<script src=""></script>  _x000D_
<div ng-app="myApp" ng-controller="dateCtrl">      _x000D_
    Today is {{today | utcDate}}       _x000D_

python: restarting a loop

Here is an example using a generator's send() method:

def restartable(seq):
    while True:
        for item in seq:
            restart = yield item
            if restart:
            raise StopIteration

Example Usage:

x = [1, 2, 3, 4, 5]
total = 0
r = restartable(x)
for item in r:
    if item == 5 and total < 100:
        total += r.send(True) 
        total += item

What are Runtime.getRuntime().totalMemory() and freeMemory()?

JVM heap size can be growable and shrinkable by the Garbage-Collection mechanism. But, it can't allocate over maximum memory size: Runtime.maxMemory. This is the meaning of maximum memory. Total memory means the allocated heap size. And free memory means the available size in total memory.

example) java -Xms20M -Xmn10M -Xmx50M ~~~. This means that jvm should allocate heap 20M on start(ms). In this case, total memory is 20M. free memory is 20M-used size. If more heap is needed, JVM allocate more but can't over 50M(mx). In the case of maximum, total memory is 50M, and free size is 50M-used size. As for minumum size(mn), if heap is not used much, jvm can shrink heap size to 10M.

This mechanism is for efficiency of memory. If small java program run on huge fixed size heap memory, so much memory may be wasteful.

What Regex would capture everything from ' mark to the end of a line?


Starting with a single quote ('), match any character (.) zero or more times (*) until the end of the line ($).


Standard SQL syntax is

DROP TABLE table_name;

IF EXISTS is not standard; different platforms might support it with different syntax, or not support it at all. In PostgreSQL, the syntax is


The first one will throw an error if the table doesn't exist, or if other database objects depend on it. Most often, the other database objects will be foreign key references, but there may be others, too. (Views, for example.) The second will not throw an error if the table doesn't exist, but it will still throw an error if other database objects depend on it.

To drop a table, and all the other objects that depend on it, use one of these.


Use CASCADE with great care.

SqlBulkCopy - The given value of type String from the data source cannot be converted to type money of the specified target column

Not going to be everyone's fix, but it was for me:

So, i ran across this exact issue. The problem I seemed to have was when my DataTable didnt have an ID column, but the target destination had one with a primary key.

When i adapted my DataTable to have an id, the copy worked perfectly.

In my scenario, the Id column isnt very important to have the primary key so i deleted this column from the target destination table and the SqlBulkCopy is working without issue.

What is your most productive shortcut with Vim?

Spend 30 mins doing the vim tutorial (run vimtutor instead of vim in terminal). You will learn the basic movements, and some keystrokes, this will make you at least as productive with vim as with the text editor you used before. After that, well, read Jim Dennis' answer again :)

OWIN Startup Class Missing

It is also possible to get this exception (even when you have a correctly configured startup class) if running through IIS Express and your virtual directory is not configured correctly.

When I encountered this issue, the resolution was simply to press the 'Create Virtual Directory' button in the 'Web' tab of project properties (Using Visual Studio 2013)

UTF-8 encoding in JSP page

I also had an issue displaying charectors like "? U".I added the following to my web.xml.


This solved the issue in the pages except header. Tried many ways to solve this and nothing worked in my case. The issue with header was header jsp page is included from another jsp. So gave the encoding to the import and that solved my problem.

<c:import url="/Header1.jsp" charEncoding="UTF-8"/>


Structs in Javascript

I always use object literals

{id: 1, speaker:"john", country: "au"}

PHP string "contains"

You can use these string functions,

strstr — Find the first occurrence of a string

stristr — Case-insensitive strstr()

strrchr — Find the last occurrence of a character in a string

strpos — Find the position of the first occurrence of a substring in a string

strpbrk — Search a string for any of a set of characters

If that doesn't help then you should use preg regular expression

preg_match — Perform a regular expression match

Leading zeros for Int in Swift

Unlike the other answers that use a formatter, you can also just add an "0" text in front of each number inside of the loop, like this:

for myInt in 1...3 {
    println("0" + "\(myInt)")

But formatter is often better when you have to add suppose a designated amount of 0s for each seperate number. If you only need to add one 0, though, then it's really just your pick.

How to include multiple js files using jQuery $.getScript() method

I implemented a simple function to load multiple scripts in parallel:


function getScripts(scripts, callback) {
    var progress = 0;
    scripts.forEach(function(script) { 
        $.getScript(script, function () {
            if (++progress == scripts.length) callback();


getScripts(["script1.js", "script2.js"], function () {
    // do something...

How to format column to number format in Excel sheet?

This will format column A as text, B as General, C as a number.

Sub formatColumns()
 Columns(1).NumberFormat = "@"
 Columns(2).NumberFormat = "General"
 Columns(3).NumberFormat = "0"
End Sub

Error LNK2019: Unresolved External Symbol in Visual Studio

When you have everything #included, an unresolved external symbol is often a missing * or & in the declaration or definition of a function.

MySQL Query GROUP BY day / month / year

If your search is over several years, and you still want to group monthly, I suggest:

version #1:

SELECT SQL_NO_CACHE YEAR(record_date), MONTH(record_date), COUNT(*)
FROM stats
GROUP BY DATE_FORMAT(record_date, '%Y%m')

version #2 (more efficient):

SELECT SQL_NO_CACHE YEAR(record_date), MONTH(record_date), COUNT(*)
FROM stats
GROUP BY YEAR(record_date)*100 + MONTH(record_date)

I compared these versions on a big table with 1,357,918 rows (), and the 2nd version appears to have better results.

version1 (average of 10 executes): 1.404 seconds
version2 (average of 10 executes): 0.780 seconds

(SQL_NO_CACHE key added to prevent MySQL from CACHING to queries.)

Correct way to set Bearer token with CURL

If you are working with a private token instead (like Gitlab API), you should replace:

$authorization = "Authorization: Bearer 080042cad6356ad5dc0a720c18b53b8e53d4c274"


$authorization = "PRIVATE-TOKEN 080042cad6356ad5dc0a720c18b53b8e53d4c274";

How can I get the last character in a string?

Javascript strings have a length property that will tell you the length of the string.

Then all you have to do is use the substr() function to get the last character:

var myString = "Test3";
var lastChar = myString.substr(myString.length -1);

edit: yes, or use the array notation as the other posts before me have done.

Lots of String functions explained here

javac is not recognized as an internal or external command, operable program or batch file

You mistyped the set command – you missed the backslash after C:. It should be:

C:\>set path=C:\Program Files (x86)\Java\jdk1.7.0\bin

Javascript Drag and drop for touch devices

Thanks for the above codes! - I tried several options and this was the ticket. I had problems in that preventDefault was preventing scrolling on the ipad - I am now testing for draggable items and it works great so far.

if ( == 'draggable_item' ) {

How does Python's super() work with multiple inheritance?

This is detailed with a reasonable amount of detail by Guido himself in his blog post Method Resolution Order (including two earlier attempts).

In your example, Third() will call First.__init__. Python looks for each attribute in the class's parents as they are listed left to right. In this case, we are looking for __init__. So, if you define

class Third(First, Second):

Python will start by looking at First, and, if First doesn't have the attribute, then it will look at Second.

This situation becomes more complex when inheritance starts crossing paths (for example if First inherited from Second). Read the link above for more details, but, in a nutshell, Python will try to maintain the order in which each class appears on the inheritance list, starting with the child class itself.

So, for instance, if you had:

class First(object):
    def __init__(self):
        print "first"

class Second(First):
    def __init__(self):
        print "second"

class Third(First):
    def __init__(self):
        print "third"

class Fourth(Second, Third):
    def __init__(self):
        super(Fourth, self).__init__()
        print "that's it"

the MRO would be [Fourth, Second, Third, First].

By the way: if Python cannot find a coherent method resolution order, it'll raise an exception, instead of falling back to behavior which might surprise the user.

Edited to add an example of an ambiguous MRO:

class First(object):
    def __init__(self):
        print "first"

class Second(First):
    def __init__(self):
        print "second"

class Third(First, Second):
    def __init__(self):
        print "third"

Should Third's MRO be [First, Second] or [Second, First]? There's no obvious expectation, and Python will raise an error:

TypeError: Error when calling the metaclass bases
    Cannot create a consistent method resolution order (MRO) for bases Second, First

Edit: I see several people arguing that the examples above lack super() calls, so let me explain: The point of the examples is to show how the MRO is constructed. They are not intended to print "first\nsecond\third" or whatever. You can – and should, of course, play around with the example, add super() calls, see what happens, and gain a deeper understanding of Python's inheritance model. But my goal here is to keep it simple and show how the MRO is built. And it is built as I explained:

>>> Fourth.__mro__
(<class '__main__.Fourth'>,
 <class '__main__.Second'>, <class '__main__.Third'>,
 <class '__main__.First'>,
 <type 'object'>)

Can someone explain __all__ in Python?

From (An Unofficial) Python Reference Wiki:

The public names defined by a module are determined by checking the module's namespace for a variable named __all__; if defined, it must be a sequence of strings which are names defined or imported by that module. The names given in __all__ are all considered public and are required to exist. If __all__ is not defined, the set of public names includes all names found in the module's namespace which do not begin with an underscore character ("_"). __all__ should contain the entire public API. It is intended to avoid accidentally exporting items that are not part of the API (such as library modules which were imported and used within the module).

How to pause for specific amount of time? (Excel/VBA)

I usually use the Timer function to pause the application. Insert this code to yours

T0 = Timer
    Delay = Timer - T0
Loop Until Delay >= 1 'Change this value to pause time for a certain amount of seconds

how to bind img src in angular 2 in ngFor?

Angular 2 and Angular 4 

In a ngFor loop it must be look like this:

<div class="column" *ngFor="let u of events ">
                <div class="thumb">
                    <img src="assets/uploads/{{u.image}}">
                <div class="info">
                    <img src="assets/uploads/{{u.image}}">

How to install iPhone application in iPhone Simulator

I see you have a problem. Try building your app as Release and then check out your source codes build folder. It may be called Release-iphonesimulator. Inside here will be the app. Then go to (home folder)/Library/Application Support/iPhone Simulator (if you can't find it, try pressing Command - J and choosing arrange by name). Go to an OS that has apps in it in the iPhone sim, like 4.1. In that folder there should be an Applications folder. Open that, and there should be folders with random lettering. Pick any one, and replace it with the app you have. Make sure to delete anything in the little folders!

If it doesn't work, then I'm dumbfounded.

Set cellpadding and cellspacing in CSS?


For controlling "cellpadding" in CSS, you can simply use padding on table cells. E.g. for 10px of "cellpadding":

td { 
    padding: 10px;

For "cellspacing", you can apply the border-spacing CSS property to your table. E.g. for 10px of "cellspacing":

table { 
    border-spacing: 10px;
    border-collapse: separate;

This property will even allow separate horizontal and vertical spacing, something you couldn't do with old-school "cellspacing".

Issues in IE = 7

This will work in almost all popular browsers except for Internet Explorer up through Internet Explorer 7, where you're almost out of luck. I say "almost" because these browsers still support the border-collapse property, which merges the borders of adjoining table cells. If you're trying to eliminate cellspacing (that is, cellspacing="0") then border-collapse:collapse should have the same effect: no space between table cells. This support is buggy, though, as it does not override an existing cellspacing HTML attribute on the table element.

In short: for non-Internet Explorer 5-7 browsers, border-spacing handles you. For Internet Explorer, if your situation is just right (you want 0 cellspacing and your table doesn't have it defined already), you can use border-collapse:collapse.

table { 
    border-spacing: 0;
    border-collapse: collapse;

Note: For a great overview of CSS properties that one can apply to tables and for which browsers, see this fantastic Quirksmode page.

Reading string from input with space character?

"%s" will read the input until whitespace is reached.

gets might be a good place to start if you want to read a line (i.e. all characters including whitespace until a newline character is reached).

Plot different DataFrames in the same figure

Just to enhance @adivis12 answer, you don't need to do the if statement. Put it like this:

fig, ax = plt.subplots()
for BAR in dict_of_dfs.keys():

var functionName = function() {} vs function functionName() {}

I prefer defining function as variable:

let first = function(x){
   return x[0];

Instead of:

function first(){

Because i can use expressions and decorators when defining the function. For example:

let safe = function(f){
  try {f()...}
let last = safe(function(x){return x[0]}).

Also with ES6 its much shorter:

 let last = x => x[0]
 function last(x){
     return x[0];

let last = safe(x => x[0]);

How do I put variable values into a text string in MATLAB?

I was looking for something along what you wanted, but wanted to put it back into a variable.

So this is what I did

variable = ['hello this is x' x ', this is now y' y ', finally this is d:' d]


variable = [str1 str2 str3 str4 str5 str6]

Multiple radio button groups in one form

in input field make name same like

<input type="radio" name="option" value="option1">
<input type="radio" name="option" value="option2" >
<input type="radio" name="option" value="option3" >
<input type="radio" name="option" value="option3" >

Database Structure for Tree Data Structure

You mention the most commonly implemented, which is Adjacency List:

There are other models as well, including materialized path and nested sets:

Joe Celko has written a book on this subject, which is a good reference from a general SQL perspective (it is mentioned in the nested set article link above).

Also, Itzik Ben-Gann has a good overview of the most common options in his book "Inside Microsoft SQL Server 2005: T-SQL Querying".

The main things to consider when choosing a model are:

1) Frequency of structure change - how frequently does the actual structure of the tree change. Some models provide better structure update characteristics. It is important to separate structure changes from other data changes however. For example, you may want to model a company's organizational chart. Some people will model this as an adjacency list, using the employee ID to link an employee to their supervisor. This is usually a sub-optimal approach. An approach that often works better is to model the org structure separate from employees themselves, and maintain the employee as an attribute of the structure. This way, when an employee leaves the company, the organizational structure itself does not need to be changes, just the association with the employee that left.

2) Is the tree write-heavy or read-heavy - some structures work very well when reading the structure, but incur additional overhead when writing to the structure.

3) What types of information do you need to obtain from the structure - some structures excel at providing certain kinds of information about the structure. Examples include finding a node and all its children, finding a node and all its parents, finding the count of child nodes meeting certain conditions, etc. You need to know what information will be needed from the structure to determine the structure that will best fit your needs.

Using the AND and NOT Operator in Python

You should write :

if (self.a != 0) and (self.b != 0) :

"&" is the bit wise operator and does not suit for boolean operations. The equivalent of "&&" is "and" in Python.

A shorter way to check what you want is to use the "in" operator :

if 0 not in (self.a, self.b) :

You can check if anything is part of a an iterable with "in", it works for :

  • Tuples. I.E : "foo" in ("foo", 1, c, etc) will return true
  • Lists. I.E : "foo" in ["foo", 1, c, etc] will return true
  • Strings. I.E : "a" in "ago" will return true
  • Dict. I.E : "foo" in {"foo" : "bar"} will return true

As an answer to the comments :

Yes, using "in" is slower since you are creating an Tuple object, but really performances are not an issue here, plus readability matters a lot in Python.

For the triangle check, it's easier to read :

0 not in (self.a, self.b, self.c)


(self.a != 0) and (self.b != 0) and (self.c != 0) 

It's easier to refactor too.

Of course, in this example, it really is not that important, it's very simple snippet. But this style leads to a Pythonic code, which leads to a happier programmer (and losing weight, improving sex life, etc.) on big programs.

Simple JavaScript problem: onClick confirm not preventing default action

I've had issue with IE7 and returning false before.

Check my answer here to another problem: Javascript not running on IE

R not finding package even after package installation

I had this problem and the issue was that I had the package loaded in another R instance. Simply closing all R instances and installing on a fresh instance allowed for the package to be installed.

Generally, you can also install if every remaining instance has never loaded the package as well (even if it installed an old version).

css to make bootstrap navbar transparent

For Spring + Thymeleaf (boostrap) project i usually use:

Inside css the following code

.navbar-inner {

Inside the HTML the line

<nav class="navbar-inner">

How to reload the current state?

Everything failed for me. Only thing that adding cache-view="false" into the view which I want to reload when going to it.

from this issue

Styling JQuery UI Autocomplete

Based on @md-nazrul-islam reply, This is what I did with SCSS:

ul.ui-autocomplete {
    position: absolute;
    top: 100%;
    left: 0;
    z-index: 1000;
    float: left;
    display: none;
    min-width: 160px;
    margin: 0 0 10px 25px;
    list-style: none;
    background-color: #ffffff;
    border: 1px solid #ccc;
    border-color: rgba(0, 0, 0, 0.2);
    //@include border-radius(5px);
    @include box-shadow( rgba(0, 0, 0, 0.1) 0 5px 10px );
    @include background-clip(padding-box);
    *border-right-width: 2px;
    *border-bottom-width: 2px;

        padding:0 .5em;
            background: #F7F7F7;


Bundling data files with PyInstaller (--onefile)

The most common complaint/question I've seen wrt PyInstaller is "my code can't find a data file which I definitely included in the bundle, where is it?", and it isn't easy to see what/where your code is searching because the extracted code is in a temp location and is removed when it exits. Add this bit of code to see what's included in your onefile and where it is, using @Jonathon Reinhart's resource_path()

for root, dirs, files in os.walk(resource_path("")):
    for file in files:
        print( "  ",file)

How do I create a user account for basic authentication?

I was able to achieve Basic Authentication on Windows Server 2012 doing the following:

Select your site within IIS and choose Authentication enter image description here

Ensure Basic Authentication is the only enabled option enter image description here

THEN! Add a username and password via the Server Manager. Select Tools -> Computer Management enter image description here

Under System Tools -> Local Users and Groups -> Users right-click anywhere in the middle pane, choose New User.. then fill in the credentials you want to use. enter image description here

Now when you navigate to the site in the browser you should get prompted with an authentication dialog:

enter image description here

Why is January month 0 in Java Calendar?

In Java 8, there is a new Date/Time API JSR 310 that is more sane. The spec lead is the same as the primary author of JodaTime and they share many similar concepts and patterns.

Comment out HTML and PHP together

I found the following solution pretty effective if you need to comment a lot of nested HTML + PHP code.

Wrap all the content in this:


Here goes your PHP + HTML code


How to define a connection string to a SQL Server 2008 database?

Copy/Paste what is below into your code:

SqlConnection cnTrupp = new SqlConnection("Initial Catalog = Database;Data Source = localhost;Persist Security Info=True;Integrated Security = True;");

Keep in mind that this solution uses your windows account to log in.

As John and Adam have said, this has to do with how you are logging in (or not logging in). Look at the link John provided to get a better explanation.

How to easily initialize a list of Tuples?

One technique I think is a little easier and that hasn't been mentioned before here:

var asdf = new [] { 
    (Age: 1, Name: "cow"), 
    (Age: 2, Name: "bird")

I think that's a little cleaner than:

var asdf = new List<Tuple<int, string>> { 
    (Age: 1, Name: "cow"), 
    (Age: 2, Name: "bird")

Python URLLib / URLLib2 POST

u = urllib2.urlopen('http://myserver/inout-tracker', data)
h.request('POST', '/inout-tracker/index.php', data, headers)

Using the path /inout-tracker without a trailing / doesn't fetch index.php. Instead the server will issue a 302 redirect to the version with the trailing /.

Doing a 302 will typically cause clients to convert a POST to a GET request.

How to specify an alternate location for the .m2 folder or settings.xml permanently?

Below is the configuration in Maven software by default in MAVEN_HOME\conf\settings.xml.

  <!-- localRepository
   | The path to the local repository maven will use to store artifacts.
   | Default: ~/.m2/repository

Add the below line under this configuration, will fulfill the requirement.


Ex: <localRepository>D:/MYNAME/settings/.m2/repository</localRepository>

How to use source: function()... and AJAX in JQuery UI autocomplete

Set the auto complete:

    source: queryDB

The source function that gets the data:

function queryDB(request, response) {
    var query = request.term;
    var data = getDataFromDB(query);
    response(data); //puts the results on the UI

how to run vibrate continuously in iphone?

iOS 5 has implemented Custom Vibrations mode. So in some cases variable vibration is acceptable. The only thing is unknown what library deals with that (pretty sure not CoreTelephony) and if it is open for developers. So keep on searching.

How do I convert a datetime to date?

Answer updated to Python 3.7 and more

Here is how you can turn a date-and-time object

(aka datetime.datetime object, the one that is stored inside models.DateTimeField django model field)

into a date object (aka object):

from datetime import datetime

#your date-and-time object
# let's supposed it is defined as
datetime_element = datetime(2020, 7, 10, 12, 56, 54, 324893)

# where
# datetime_element = datetime(year, month, day, hour, minute, second, milliseconds)

# WHAT YOU WANT: your date-only object
date_element =

And just to be clear, if you print those elements, here is the output :


2020-07-10 12:56:54.324893



Java converting int to hex and back again

  • int to Hex :

  • Hex to int :

    Integer.valueOf(hexString, 16).intValue();

You may also want to use long instead of int (if the value does not fit the int bounds):

  • Hex to long:

    Long.valueOf(hexString, 16).longValue()
  • long to Hex


PHP write file from input to txt

The problems you have are because of the extra <form> you have, that your data goes in GET method, and you are accessing the data in PHP using POST.

    <form action="myprocessingscript.php" method="POST">

create a trusted self-signed SSL cert for localhost (for use with Express/Node)

If you need to go a step further than @alon's detailed steps and also create a self signed ca:

  key: fs.readFileSync(NODE_SSL_KEY),
  cert: fs.readFileSync(NODE_SSL_CERT),
  ca: fs.readFileSync(NODE_SSL_CA),
}, app).listen(PORT, () => {});


"setup:https": "openssl genrsa -out src/server/ssl/localhost.key 2048
&& openssl req -new -x509 -key src/server/ssl/localhost.key -out src/server/ssl/localhost.crt -config src/server/ssl/localhost.cnf
&& openssl req -new -out src/server/ssl/localhost.csr -config src/server/ssl/localhost.cnf
&& openssl x509 -req -in src/server/ssl/localhost.csr -CA src/server/ssl/localhost.crt -CAkey src/server/ssl/localhost.key -CAcreateserial -out src/server/ssl/ca.crt",

Using the localhost.cnf as described:

distinguished_name = req_distinguished_name
x509_extensions = v3_req
prompt = no
C = UK
ST = State
L = Location
O = Organization Name
OU = Organizational Unit 
CN =
keyUsage = critical, digitalSignature, keyAgreement
extendedKeyUsage = serverAuth
subjectAltName = @alt_names
DNS.1 =
DNS.2 =
DNS.3 = localhost

How to get ALL child controls of a Windows Forms form of a specific type (Button/Textbox)?

This may work:

Public Function getControls(Of T)() As List(Of T)
    Dim st As New Stack(Of Control)
    Dim ctl As Control
    Dim li As New List(Of T)


    While st.Count > 0
        ctl = st.Pop
        For Each c In ctl.Controls
            st.Push(CType(c, Control))
            If c.GetType Is GetType(T) Then
                li.Add(CType(c, T))
            End If
    End While

    Return li
End Function

I think the function to get all controls you are talking about is only available to WPF.

How do I hide the PHP explode delimiter from submitted form results?

You could try a different approach like read the file line by line instead of dealing with all this nl2br / explode stuff.

$fh = fopen("employees.txt", "r"); if ($fh) {     while (($line = fgets($fh)) !== false) {         $line = trim($line);         echo "<option value='".$line."'>".$line."</option>";     } } else {     // error opening the file, do something } 

Also maybe just doing a trim (remove whitespace from beginning/end of string) is your issue?

And maybe people are just misunderstanding what you mean by "submitting results to a spreadsheet" -- are you doing this with code? or a copy/paste from an HTML page into a spreadsheet? Maybe you can explain that in more detail. The delimiter for which you split the lines of the file shouldn't be displaying in the output anyway unless you have unexpected output for some other reason.

How to recover corrupted Eclipse workspace?

I haven't been able to avoid rebuilding workspace occasionally (one or twice over several years of using eclipse). Delete the .metedata and rebuild.

Update one MySQL table with values from another

It depends what is a use of those tables, but you might consider putting trigger on original table on insert and update. When insert or update is done, update the second table based on only one item from the original table. It will be quicker.

Implementing multiple interfaces with Java - is there a way to delegate?

There's no pretty way. You might be able to use a proxy with the handler having the target methods and delegating everything else to them. Of course you'll have to use a factory because there'll be no constructor.

Razor HtmlHelper Extensions (or other namespaces for views) Not Found

As the accepted answer suggests you can add "using" to all views by adding to section of config file.

But for a single view you could just use

@using SomeNamespace.Extensions

Create new user in MySQL and give it full access to one database

In case the host part is omitted it defaults to the wildcard symbol %, allowing all hosts.

CREATE USER 'service-api';

GRANT ALL PRIVILEGES ON the_db.* TO 'service-api' IDENTIFIED BY 'the_password'

SELECT * FROM mysql.user;
SHOW GRANTS FOR 'service-api'

Python basics printing 1 to 100

Because the condition is never true. i.e. count !=100 never executes when you put count=count+3 or count =count+9. try this out..while count<100

How to alter a column and change the default value?

Accepted Answer works good.

In case of Invalid use of NULL value error, on NULL values, update all null values to default value in that column and then try to do the alter.

UPDATE foobar_data SET col = '{}' WHERE col IS NULL;


Which terminal command to get just IP address and nothing else?

To print only the IP address of eth0, without other text:

ifconfig eth0 | grep -Po '(?<=inet addr:)[\d.]+'

To determine your primary interface (because it might not be "eth0"), use:

route | grep ^default | sed "s/.* //"

The above two lines can be combined into a single command like this:

ifconfig `route | grep ^default | sed "s/.* //"` \
  | grep -Po '(?<=inet addr:)[\d.]+'

jQuery validation: change default error message

To remove all default error messages use

$.validator.messages.required = "";

How to debug .htaccess RewriteRule not working

To test your htaccess rewrite rules, simply fill in the url that you're applying the rules to, place the contents of your htaccess on the larger input area and press "Test" button.

SQL Server Output Clause into a scalar variable

Way later but still worth mentioning is that you can also use variables to output values in the SET clause of an UPDATE or in the fields of a SELECT;

DECLARE @val1 int;
DECLARE @val2 int;
UPDATE [dbo].[PortalCounters_TEST]
SET @val1 = NextNum, @val2 = NextNum = NextNum + 1
WHERE [Condition] = 'unique value'
SELECT @val1, @val2

In the example above @val1 has the before value and @val2 has the after value although I suspect any changes from a trigger would not be in val2 so you'd have to go with the output table in that case. For anything but the simplest case, I think the output table will be more readable in your code as well.

One place this is very helpful is if you want to turn a column into a comma-separated list;

DECLARE @list varchar(max) = '';
DECLARE @comma varchar(2) = '';
SELECT @list = @list + @comma + County, @comma = ', ' FROM County
print @list

Carry Flag, Auxiliary Flag and Overflow Flag in Assembly

Carry Flag

The rules for turning on the carry flag in binary/integer math are two:

  1. The carry flag is set if the addition of two numbers causes a carry out of the most significant (leftmost) bits added. 1111 + 0001 = 0000 (carry flag is turned on)

  2. The carry (borrow) flag is also set if the subtraction of two numbers requires a borrow into the most significant (leftmost) bits subtracted. 0000 - 0001 = 1111 (carry flag is turned on) Otherwise, the carry flag is turned off (zero).

    • 0111 + 0001 = 1000 (carry flag is turned off [zero])
    • 1000 - 0001 = 0111 (carry flag is turned off [zero])

In unsigned arithmetic, watch the carry flag to detect errors.

In signed arithmetic, the carry flag tells you nothing interesting.

Overflow Flag

The rules for turning on the overflow flag in binary/integer math are two:

  1. If the sum of two numbers with the sign bits off yields a result number with the sign bit on, the "overflow" flag is turned on. 0100 + 0100 = 1000 (overflow flag is turned on)

  2. If the sum of two numbers with the sign bits on yields a result number with the sign bit off, the "overflow" flag is turned on. 1000 + 1000 = 0000 (overflow flag is turned on)

Otherwise the "overflow" flag is turned off

  • 0100 + 0001 = 0101 (overflow flag is turned off)
  • 0110 + 1001 = 1111 (overflow flag turned off)
  • 1000 + 0001 = 1001 (overflow flag turned off)
  • 1100 + 1100 = 1000 (overflow flag is turned off)

Note that you only need to look at the sign bits (leftmost) of the three numbers to decide if the overflow flag is turned on or off.

If you are doing two's complement (signed) arithmetic, overflow flag on means the answer is wrong - you added two positive numbers and got a negative, or you added two negative numbers and got a positive.

If you are doing unsigned arithmetic, the overflow flag means nothing and should be ignored.

For more clarification please refer:

How to concatenate strings in a Windows batch file?

Note that the variables @fname or @ext can be simply concatenated. This:

forfiles /S /M *.pdf /C "CMD /C REN @path @fname_old.@ext"

renames all PDF files to "filename_old.pdf"

Java Enum return Int

Simply call the ordinal() method on an enum value, to retrieve its corresponding number. There's no need to declare an addition attribute with its value, each enumerated value gets its own number by default, assigned starting from zero, incrementing by one for each value in the same order they were declared.

You shouldn't depend on the int value of an enum, only on its actual value. Enums in Java are a different kind of monster and are not like enums in C, where you depend on their integer code.

Regarding the example you provided in the question, Font.PLAIN works because that's just an integer constant of the Font class. If you absolutely need a (possibly changing) numeric code, then an enum is not the right tool for the job, better stick to numeric constants.

How to validate numeric values which may contain dots or commas?

If you want to be very permissive, required only two final digits with comma or dot:


How can you create multiple cursors in Visual Studio Code

New version (Visual Studio 0.3.0) support more multi cursor feature.

Here's multi-cursor improvements that we've made.

?D selects the word at the cursor, or the next occurrence of the current selection.
?K ?D moves the last added cursor to next occurrence of the current selection.
The two actions pick up the matchCase and matchWholeWord settings of the find widget.
?U undoes the last cursor action, so if you added one cursor too many or made a mistake, press ?U to return to the previous cursor state.
Insert cursor above (???) and insert cursor below (???) now reveals the last added cursor, making it easier to work with multi-cursors spanning more than one screen height (i.e., working with 300 lines while only 80 fit in the screen).

And short cut of select multi cursor change into cmd + d(it's same as Sublime Text. lol)

We can expect that next version supports more convenient feature about multi cursor ;)

Any reason not to use '+' to concatenate two strings?

There is nothing wrong in concatenating two strings with +. Indeed it's easier to read than ''.join([a, b]).

You are right though that concatenating more than 2 strings with + is an O(n^2) operation (compared to O(n) for join) and thus becomes inefficient. However this has not to do with using a loop. Even a + b + c + ... is O(n^2), the reason being that each concatenation produces a new string.

CPython2.4 and above try to mitigate that, but it's still advisable to use join when concatenating more than 2 strings.

Shortcut to exit scale mode in VirtualBox

I was having the similar issue when using VirtualBox on Ubuntu 12.04LTS. Now if anyone is using or has ever used Ubuntu, you might be aware that how things are hard sometimes when using shortcut keys in Ubuntu. For me, when i was trying to revert back the Host key, it was just not happening and the shortcut keys won't just work. I even tried the command line option to revert back the scale mode and it won't work either. Finally i found the following when all the other options fails:

Fix the Scale Mode Issue in Oracle VirtualBox in Ubuntu using the following steps:

  1. Close all virtual machines and VirtualBox windows.
  2. Find your machine config files (i.e. /home/<username>/VirtualBox VMs/ANKSVM) where ANKSVM is your VM Name and edit and change the following in ANKSVM.vbox and ANKSVM.vbox-prev files:

  3. Edit the line: <ExtraDataItem name="GUI/Scale" value="on"/> to <ExtraDataItem name="GUI/Scale" value="off"/>

  4. Restart VirtualBox

You are done.

This works every time specially when all other options fails like how it happened for me.

How do I escape a percentage sign in T-SQL?

You can use the ESCAPE keyword with LIKE. Simply prepend the desired character (e.g. '!') to each of the existing % signs in the string and then add ESCAPE '!' (or your character of choice) to the end of the query.

For example:

FROM prices
WHERE discount LIKE '%80!% off%'

This will make the database treat 80% as an actual part of the string to search for and not 80(wildcard).

MSDN Docs for LIKE

Adding to an ArrayList Java

You should be able to do something like:

ArrayList<String> list = new ArrayList<String>();
for( String s : foo )

Mobile Safari: Javascript focus() method on inputfield only works with click?

I faced the same issue recently. I found a solution that apparently works for all devices. You can't do async focus programmatically but you can switch focus to your target input when some other input is already focused. So what you need to do is create, hide, append to DOM & focus a fake input on trigger event and, when the async action completes, just call focus again on the target input. Here's an example snippet - run it on your mobile.


Here's a fiddle with the same code. Apparently you can't run attached snippets on mobiles (or I'm doing something wrong).

var $triggerCheckbox = $("#trigger-checkbox");_x000D_
var $targetInput = $("#target-input");_x000D_
// Create fake & invisible input_x000D_
var $fakeInput = $("<input type='text' />")_x000D_
    position: "absolute",_x000D_
    width: $targetInput.outerWidth(), // zoom properly (iOS)_x000D_
    height: 0, // hide cursor (font-size: 0 will zoom to quarks level) (iOS)_x000D_
    opacity: 0, // make input transparent :]_x000D_
var delay = 2000; // That's crazy long, but good as an example_x000D_
$triggerCheckbox.on("change", function(event) {_x000D_
  // Disable input when unchecking trigger checkbox (presentational purpose)_x000D_
  if (! {_x000D_
    return $targetInput_x000D_
      .attr("disabled", true)_x000D_
      .attr("placeholder", "I'm disabled");_x000D_
  // Prepend to target input container and focus fake input_x000D_
  // Update placeholder (presentational purpose)_x000D_
  $targetInput.attr("placeholder", "Wait for it...");_x000D_
  // setTimeout, fetch or any async action will work_x000D_
  setTimeout(function() {_x000D_
    // Shift focus to target input_x000D_
      .attr("disabled", false)_x000D_
      .attr("placeholder", "I'm alive!")_x000D_
    // Remove fake input - no need to keep it in DOM_x000D_
  }, delay);_x000D_
label {_x000D_
  display: block;_x000D_
  margin-top: 20px;_x000D_
input {_x000D_
  box-sizing: border-box;_x000D_
  font-size: inherit;_x000D_
#container {_x000D_
  position: relative;_x000D_
#target-input {_x000D_
  width: 250px;_x000D_
  padding: 10px;_x000D_
<script src=""></script>_x000D_
<div id="container">_x000D_
  <input type="text" id="target-input" placeholder="I'm disabled" />_x000D_
    <input type="checkbox" id="trigger-checkbox" />_x000D_
    focus with setTimetout_x000D_

Convert datetime to valid JavaScript date

One can use the getmonth and getday methods to get only the date.

Here I attach my solution:

var fullDate = new Date(); console.log(fullDate);_x000D_
var twoDigitMonth = fullDate.getMonth() + "";_x000D_
if (twoDigitMonth.length == 1)_x000D_
    twoDigitMonth = "0" + twoDigitMonth;_x000D_
var twoDigitDate = fullDate.getDate() + "";_x000D_
if (twoDigitDate.length == 1)_x000D_
    twoDigitDate = "0" + twoDigitDate;_x000D_
var currentDate = twoDigitDate + "/" + twoDigitMonth + "/" + fullDate.getFullYear(); console.log(currentDate);

Getting IP address of client

I believe it is more to do with how your network is configured. Servlet is simply giving you the address it is finding.

I can suggest two workarounds. First try using IPV4. See this SO Answer

Also, try using the request.getRemoteHost() method to get the names of the machines. Surely the names are independent of whatever IP they are mapped to.

I still think you should discuss this with your infrastructure guys.

Leave out quotes when copying from cell

If you want to select multiple cells and copy their values to the clipboard without all those annoying quotes the following code may be useful. This is an enhancement of the code given above from user3616725.

Sub CopyCells()
 'Attach Microsoft Forms 2.0 Library: tools\references\Browse\FM20.DLL
 'Then set a keyboard shortcut to the CopyCells Macro (eg Crtl T)
 Dim objData As New DataObject
 Dim cell As Object
 Dim concat As String
 Dim cellValue As String
 CR = ""
  For Each cell In Selection
  If IsNumeric(cell.Value) Then
   cellValue = LTrim(Str(cell.Value))
   cellValue = cell.Value
  End If
  concat = concat + CR + cellValue
  CR = Chr(13)
 objData.SetText (concat)
End Sub

jQuery equivalent of JavaScript's addEventListener method

The closest thing would be the bind function:

$('#foo').bind('click', function() {
  alert('User clicked on "foo."');

How can I convert a zero-terminated byte array to string?

Simplistic solution:

str := fmt.Sprintf("%s", byteArray)

I'm not sure how performant this is though.