Programs & Examples On #Selenium

Selenium is a popular open-source tool for automating web browsers. When using this tag, also include other tags for the specific components you are using, e.g. selenium-webdriver for the language bindings, selenium-ide, selenium-grid, etc.

Selenium using Java - The path to the driver executable must be set by the webdriver.gecko.driver system property

I use from selenium-java-3.141.59 in windows 10 and solved my problem with this code:

System.setProperty("webdriver.gecko.driver", "C:\\gecko\\geckodriver.exe");
System.setProperty("webdriver.firefox.bin","C:\\Program Files\\Mozilla Firefox\\firefox.exe");
WebDriver driver = new FirefoxDriver();

How to check if an alert exists using WebDriver?

I found catching exception of driver.switchTo().alert(); is so slow in Firefox (FF V20 & selenium-java-2.32.0).`

So I choose another way:

    private static boolean isDialogPresent(WebDriver driver) {
        try {
            driver.getTitle();
            return false;
        } catch (UnhandledAlertException e) {
            // Modal dialog showed
            return true;
        }
    }

And it's a better way when most of your test cases is NO dialog present (throwing exception is expensive).

Webdriver Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms

Update selenium jars, download selenium 2.31.0

This issue has been resolved by the selenium guys

This was a compatibility issue.

Cheers

Class has been compiled by a more recent version of the Java Environment

For temporary solution just right click on Project => Properties => Java compiler => over there please select compiler compliance level 1.8 => .class compatibility 1.8 => source compatibility 1.8.

Then your code will start to execute on version 1.8.

How to write multiple conditions of if-statement in Robot Framework

You should use small caps "or" and "and" instead of OR and AND.

And beware also the spaces/tabs between keywords and arguments (you need at least two spaces).

Here is a code sample with your three keywords working fine:

Here is the file ts.txt:

  *** test cases ***
  mytest
    ${color} =  set variable  Red
    Run Keyword If  '${color}' == 'Red'  log to console  \nexecuted with single condition
    Run Keyword If  '${color}' == 'Red' or '${color}' == 'Blue' or '${color}' == 'Pink'  log to console  \nexecuted with multiple or

    ${color} =  set variable  Blue
    ${Size} =  set variable  Small
    ${Simple} =  set variable  Simple
    ${Design} =  set variable  Simple
    Run Keyword If  '${color}' == 'Blue' and '${Size}' == 'Small' and '${Design}' != '${Simple}'  log to console  \nexecuted with multiple and

    ${Size} =  set variable  XL
    ${Design} =  set variable  Complicated
    Run Keyword Unless  '${color}' == 'Black' or '${Size}' == 'Small' or '${Design}' == 'Simple'  log to console  \nexecuted with unless and multiple or

and here is what I get when I execute it:

$ pybot ts.txt
==============================================================================
Ts
==============================================================================
mytest                                                                .
executed with single condition
executed with multiple or
executed with unless and multiple or
mytest                                                                | PASS |
------------------------------------------------------------------------------

How do I set browser width and height in Selenium WebDriver?

Here is how I do it in Python with Selenium 2.48.0:

from selenium.webdriver import Firefox
driver = Firefox()
driver.set_window_position(0, 0)
driver.set_window_size(1024, 768)

Change user-agent for Selenium web-driver

This is a short solution to change the request UserAgent on the fly.

Change UserAgent of a request with Chrome

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

driver = webdriver.Chrome(driver_path)
driver.execute_cdp_cmd('Network.setUserAgentOverride', {"userAgent":"python 2.7", "platform":"Windows"})
driver.get('http://amiunique.org')

then return your useragent:

agent = driver.execute_script("return navigator.userAgent")

Some sources

The source code of webdriver.py from SeleniumHQ (https://github.com/SeleniumHQ/selenium/blob/11c25d75bd7ed22e6172d6a2a795a1d195fb0875/py/selenium/webdriver/chrome/webdriver.py) extends its functionalities through the Chrome Devtools Protocol

def execute_cdp_cmd(self, cmd, cmd_args):
        """
        Execute Chrome Devtools Protocol command and get returned result

We can use the Chrome Devtools Protocol Viewer to list more extended functionalities (https://chromedevtools.github.io/devtools-protocol/tot/Network#method-setUserAgentOverride) as well as the parameters type to use.

Check if element is clickable in Selenium Java

List<WebElement> wb=driver.findElements(By.xpath(newXpath));
        for(WebElement we: wb){
            if(we.isDisplayed() && we.isEnabled())
            {
                we.click();
                break;
            }
        }
    }

Getting the URL of the current page using Selenium WebDriver

Put sleep. It will work. I have tried. The reason is that the page wasn't loaded yet. Check this question to know how to wait for load - Wait for page load in Selenium

Page scroll up or down in Selenium WebDriver (Selenium 2) using java

There are many ways to scroll up and down in Selenium Webdriver I always use Java Script to do the same.

Below is the code which always works for me if I want to scroll up or down

 // This  will scroll page 400 pixel vertical
  ((JavascriptExecutor)driver).executeScript("scroll(0,400)");

You can get full code from here Scroll Page in Selenium

If you want to scroll for a element then below piece of code will work for you.

je.executeScript("arguments[0].scrollIntoView(true);",element);

You will get the full doc here Scroll for specific Element

Get HTML source of WebElement in Selenium WebDriver using Python

There is not really a straightforward way of getting the HTML source code of a webelement. You will have to use JavaScript. I am not too sure about python bindings, but you can easily do like this in Java. I am sure there must be something similar to JavascriptExecutor class in Python.

 WebElement element = driver.findElement(By.id("foo"));
 String contents = (String)((JavascriptExecutor)driver).executeScript("return arguments[0].innerHTML;", element);

Execute JavaScript using Selenium WebDriver in C#

The shortest code

ChromeDriver drv = new ChromeDriver();

drv.Navigate().GoToUrl("https://stackoverflow.com/questions/6229769/execute-javascript-using-selenium-webdriver-in-c-sharp");

drv.ExecuteScript("return alert(document.title);");


Set value of input instead of sendKeys() - Selenium WebDriver nodejs

Extending from the correct answer of Andrey-Egorov using .executeScript() to conclude my own question example:

inputField = driver.findElement(webdriver.By.id('gbqfq'));
driver.executeScript("arguments[0].setAttribute('value', '" + longstring +"')", inputField);

selenium get current url after loading a page

Like you said since the xpath for the next button is the same on every page it won't work. It's working as coded in that it does wait for the element to be displayed but since it's already displayed then the implicit wait doesn't apply because it doesn't need to wait at all. Why don't you use the fact that the url changes since from your code it appears to change when the next button is clicked. I do C# but I guess in Java it would be something like:

WebDriver driver = new FirefoxDriver();
String startURL = //a starting url;
String currentURL = null;
WebDriverWait wait = new WebDriverWait(driver, 10);

foo(driver,startURL);

/* go to next page */
if(driver.findElement(By.xpath("//*[@id='someID']")).isDisplayed()){
    String previousURL = driver.getCurrentUrl();
    driver.findElement(By.xpath("//*[@id='someID']")).click();  
    driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);

    ExpectedCondition e = new ExpectedCondition<Boolean>() {
          public Boolean apply(WebDriver d) {
            return (d.getCurrentUrl() != previousURL);
          }
        };

    wait.until(e);
    currentURL = driver.getCurrentUrl();
    System.out.println(currentURL);
} 

Alert handling in Selenium WebDriver (selenium 2) with Java

This is what worked for me using Explicit Wait from here WebDriver: Advanced Usage

public void checkAlert() {
    try {
        WebDriverWait wait = new WebDriverWait(driver, 2);
        wait.until(ExpectedConditions.alertIsPresent());
        Alert alert = driver.switchTo().alert();
        alert.accept();
    } catch (Exception e) {
        //exception handling
    }
}

Cannot find firefox binary in PATH. Make sure firefox is installed

The easiest thing to do is have your grid nodes register the Firefox binary path as part of the node config. It uses the same capabilities that the client has, but allows you to pick the browser by name and let the node find it.

Please also note that the capability you want is "firefox_binary" and not "binary". You can see the full list of Firefox capabilities at this wiki page:

https://code.google.com/p/selenium/wiki/DesiredCapabilities

How to find specific lines in a table using Selenium?

Well previously, I used the approach that you can find inside the WebElement:

WebElement baseTable = driver.findElement(By.tagName("table"));
WebElement tableRow = baseTable.findElement(By.xpath("//tr[2]")); //should be the third row
webElement cellIneed = tableRow.findElement(By.xpath("//td[2]"));
String valueIneed = cellIneed.getText();

Please note that I find inside the found WebElement instance.

The above is Java code, assuming that driver variable is healthy instance of WebDriver

Setting Remote Webdriver to run tests in a remote computer using Java

This is how I got rid of the error:

WebDriverException: Error forwarding the new session cannot find : {platform=WINDOWS, ensureCleanSession=true, browserName=internet explorer, version=11}

In your nodeconfig.json, the version must be a String, not an integer.

So instead of using "version": 11 use "version": "11" (note the double quotes).

A full example of a working nodecondig.json file for a RemoteWebDriver:

{
  "capabilities":
  [
    {
      "platform": "WIN8_1",
      "browserName": "internet explorer",
      "maxInstances": 1,
      "seleniumProtocol": "WebDriver"
      "version": "11"
    }
    ,{
      "platform": "WIN7",
      "browserName": "chrome",
      "maxInstances": 4,
      "seleniumProtocol": "WebDriver"
      "version": "40"
    }
    ,{
      "platform": "LINUX",
      "browserName": "firefox",
      "maxInstances": 4,
      "seleniumProtocol": "WebDriver"
      "version": "33"
    }
  ],
  "configuration":
  {
    "proxy": "org.openqa.grid.selenium.proxy.DefaultRemoteProxy",
    "maxSession": 3,
    "port": 5555,
    "host": ip,
    "register": true,
    "registerCycle": 5000,
    "hubPort": 4444,
    "hubHost": {your-ip-address}
  }
}

How to verify an XPath expression in Chrome Developers tool or Firefox's Firebug?

By using Chrome or Opera

without any plugins, without writing any single XPath syntax character

  1. right click the required element, then "inspect"
  2. right click on highlighted element tag, choose Copy ? Copy XPath.

;)

Enter image description here

How can I control Chromedriver open window size?

If you're using the Facebook language binding for php try this:

$driver->manage()->window()->setSize(new WebDriverDimension(1024,768));

Wait until page is loaded with Selenium WebDriver for Python

You can do that very simple by this function:

def page_is_loading(driver):
    while True:
        x = driver.execute_script("return document.readyState")
        if x == "complete":
            return True
        else:
            yield False

and when you want do something after page loading complete,you can use:

Driver = webdriver.Firefox(options=Options, executable_path='geckodriver.exe')
Driver.get("https://www.google.com/")

while not page_is_loading(Driver):
    continue

Driver.execute_script("alert('page is loaded')")

Selenium: WebDriverException:Chrome failed to start: crashed as google-chrome is no longer running so ChromeDriver is assuming that Chrome has crashed

i had same problem. I was run it on terminal with "sudo geany", you should run it without "sudo" just type on terminal "geany" and it is solved for me.

SessionNotCreatedException: Message: session not created: This version of ChromeDriver only supports Chrome version 81

I had already been running a local server at the same port the session wanted to run on, and this caused the error. Shutting down that local server fixed this for me.

How to use Selenium with Python?

You just need to get selenium package imported, that you can do from command prompt using the command

pip install selenium

When you have to use it in any IDE just import this package, no other documentation required to be imported

For Eg :

import selenium 
print(selenium.__filepath__)

This is just a general command you may use in starting to check the filepath of selenium

How to gettext() of an element in Selenium Webdriver

You need to print the result of the getText(). You're currently printing the object TxtBoxContent.

getText() will only get the inner text of an element. To get the value, you need to use getAttribute().

WebElement TxtBoxContent = driver.findElement(By.id(WebelementID));
System.out.println("Printing " + TxtBoxContent.getAttribute("value"));

Select parent element of known element in Selenium

There are a couple of options there. The sample code is in Java, but a port to other languages should be straightforward.

Java:

WebElement myElement = driver.findElement(By.id("myDiv"));
WebElement parent = (WebElement) ((JavascriptExecutor) driver).executeScript(
                                   "return arguments[0].parentNode;", myElement);

XPath:

WebElement myElement = driver.findElement(By.id("myDiv"));
WebElement parent = myElement.findElement(By.xpath("./.."));

Obtaining the driver from the WebElement

Note: As you can see, for the JavaScript version you'll need the driver. If you don't have direct access to it, you can retrieve it from the WebElement using:

WebDriver driver = ((WrapsDriver) myElement).getWrappedDriver();

How to deal with certificates using Selenium?

Whenever I run into this issue with newer browsers, I just use AppRobotic Personal edition to click specific screen coordinates, or tab through the buttons and click.

Basically it's just using its macro functionality, but won't work on headless setups though.

python selenium click on button

try this:

download firefox, add the plugin "firebug" and "firepath"; after install them go to your webpage, start firebug and find the xpath of the element, it unique in the page so you can't make any mistake.

See picture: instruction

browser.find_element_by_xpath('just copy and paste the Xpath').click()

Error message: "'chromedriver' executable needs to be available in the path"

For Linux and OSX

Step 1: Download chromedriver

# You can find more recent/older versions at http://chromedriver.storage.googleapis.com/
# Also make sure to pick the right driver, based on your Operating System
wget http://chromedriver.storage.googleapis.com/81.0.4044.69/chromedriver_mac64.zip

For debian: wget https://chromedriver.storage.googleapis.com/2.41/chromedriver_linux64.zip

Step 2: Add chromedriver to /usr/local/bin

unzip chromedriver_mac64.zip
sudo mv chromedriver /usr/local/bin
sudo chown root:root /usr/local/bin/chromedriver
sudo chmod +x /usr/local/bin/chromedriver

You should now be able to run

from selenium import webdriver

browser = webdriver.Chrome()
browser.get('http://localhost:8000')

without any issues

Running Selenium WebDriver python bindings in chrome

There are 2 ways to run Selenium python tests in Google Chrome. I'm considering Windows (Windows 10 in my case):

Prerequisite: Download the latest Chrome Driver from: https://sites.google.com/a/chromium.org/chromedriver/downloads

Way 1:

i) Extract the downloaded zip file in a directory/location of your choice
ii) Set the executable path in your code as below:

self.driver = webdriver.Chrome(executable_path='D:\Selenium_RiponAlWasim\Drivers\chromedriver_win32\chromedriver.exe')

Way 2:

i) Simply paste the chromedriver.exe under /Python/Scripts/ (In my case the folder was: C:\Python36\Scripts)
ii) Now write the simple code as below:

self.driver = webdriver.Chrome()

How to switch to new window in Selenium for Python?

You can do it by using window_handles and switch_to_window method.

Before clicking the link first store the window handle as

window_before = driver.window_handles[0]

after clicking the link store the window handle of newly opened window as

window_after = driver.window_handles[1]

then execute the switch to window method to move to newly opened window

driver.switch_to_window(window_after)

and similarly you can switch between old and new window. Following is the code example

import unittest
from selenium import webdriver

class GoogleOrgSearch(unittest.TestCase):

    def setUp(self):
        self.driver = webdriver.Firefox()

    def test_google_search_page(self):
        driver = self.driver
        driver.get("http://www.cdot.in")
        window_before = driver.window_handles[0]
        print window_before
        driver.find_element_by_xpath("//a[@href='http://www.cdot.in/home.htm']").click()
        window_after = driver.window_handles[1]
        driver.switch_to_window(window_after)
        print window_after
        driver.find_element_by_link_text("ATM").click()
        driver.switch_to_window(window_before)

    def tearDown(self):
        self.driver.close()

if __name__ == "__main__":
    unittest.main()

Is there a way to get element by XPath using JavaScript in Selenium WebDriver?

**Different way to Find Element:**

IEDriver.findElement(By.id("id"));
IEDriver.findElement(By.linkText("linkText"));
IEDriver.findElement(By.xpath("xpath"));

IEDriver.findElement(By.xpath(".//*[@id='id']"));
IEDriver.findElement(By.xpath("//button[contains(.,'button name')]"));
IEDriver.findElement(By.xpath("//a[contains(.,'text name')]"));
IEDriver.findElement(By.xpath("//label[contains(.,'label name')]"));

IEDriver.findElement(By.xpath("//*[contains(text(), 'your text')]");

Check Case Sensitive:
IEDriver.findElement(By.xpath("//*[contains(lower-case(text()),'your text')]");

For exact match: 
IEDriver.findElement(By.xpath("//button[text()='your text']");

**Find NG-Element:**

Xpath == //td[contains(@ng-show,'childsegment.AddLocation')]
CssSelector == .sprite.icon-cancel

Click a button with XPath containing partial id and title in Selenium IDE

Now that you have provided your HTML sample, we're able to see that your XPath is slightly wrong. While it's valid XPath, it's logically wrong.

You've got:

//*[contains(@id, 'ctl00_btnAircraftMapCell')]//*[contains(@title, 'Select Seat')]

Which translates into:

Get me all the elements that have an ID that contains ctl00_btnAircraftMapCell. Out of these elements, get any child elements that have a title that contains Select Seat.

What you actually want is:

//a[contains(@id, 'ctl00_btnAircraftMapCell') and contains(@title, 'Select Seat')]

Which translates into:

Get me all the anchor elements that have both: an id that contains ctl00_btnAircraftMapCell and a title that contains Select Seat.

Click in OK button inside an Alert (Selenium IDE)

1| Print Alert popup text and close -I

Alert alert = driver.switchTo().alert();
System.out.println(closeAlertAndGetItsText());

2| Print Alert popup text and close -II

Alert alert = driver.switchTo().alert();
System.out.println(alert.getText()); //Print Alert popup
alert.accept(); //Close Alert popup

3| Assert Alert popup text and close

Alert alert = driver.switchTo().alert();
assertEquals("Expected Value", closeAlertAndGetItsText());

How to select element using XPATH syntax on Selenium for Python?

Check this blog by Martin Thoma. I tested the below code on MacOS Mojave and it worked as specified.

> def get_browser():
>     """Get the browser (a "driver")."""
>     # find the path with 'which chromedriver'
>     path_to_chromedriver = ('/home/moose/GitHub/algorithms/scraping/'
>                             'venv/bin/chromedriver')
>     download_dir = "/home/moose/selenium-download/"
>     print("Is directory: {}".format(os.path.isdir(download_dir)))
> 
>     from selenium.webdriver.chrome.options import Options
>     chrome_options = Options()
>     chrome_options.add_experimental_option('prefs', {
>         "plugins.plugins_list": [{"enabled": False,
>                                   "name": "Chrome PDF Viewer"}],
>         "download": {
>             "prompt_for_download": False,
>             "default_directory": download_dir
>         }
>     })
> 
>     browser = webdriver.Chrome(path_to_chromedriver,
>                                chrome_options=chrome_options)
>     return browser

Where to find 64 bit version of chromedriver.exe for Selenium WebDriver?

There is no separate 64-bit version of Chromedriver. The version available at https://sites.google.com/a/chromium.org/chromedriver/downloads works on both 32 and 64-bit Windows, against either 32-or 64-bit Chrome.

This was confirmed in the Chromedriver issue tracker: https://bugs.chromium.org/p/chromedriver/issues/detail?id=1797#c1

Yes, Chromedriver works on 64-bit Windows and against 64-bit Chrome successfully.

I came here while searching for the answer to if it works on 64-bit Chrome following the announcement that from version 58 Chrome will default to 64-bit on Windows provided certain conditions are met:
https://chromereleases.googleblog.com/2017/05/stable-channel-update-for-desktop.html

In order to improve stability, performance, and security, users who are currently on 32-bit version of Chrome, and 64-bit Windows with 4GB or more of memory and auto-update enabled will be automatically migrated to 64-bit Chrome during this update. 32-bit Chrome will still be available via the Chrome download page.

How can I start InternetExplorerDriver using Selenium WebDriver

static WebDriver driver;
System.setProperty("webdriver.ie.driver","C:\\(Path)\\IEDriverServer.exe");
driver = new InternetExplorerDriver();
driver.manage().window().maximize();
driver.get("EnterURLHere");          
driver.manage().timeouts().implicitlyWait(30,TimeUnit.SECONDS);

XPath: difference between dot and text()

enter image description here The XPath text() function locates elements within a text node while dot (.) locate elements inside or outside a text node. In the image description screenshot, the XPath text() function will only locate Success in DOM Example 2. It will not find success in DOM Example 1 because it's located between the tags.

In addition, the text() function will not find success in DOM Example 3 because success does not have a direct relationship to the element . Here's a video demo explaining the difference between text() and dot (.) https://youtu.be/oi2Q7-0ZIBg

How to select/get drop down option in Selenium 2

driver.findElement(By.id("id_dropdown_menu")).click();
driver.findElement(By.xpath("xpath_from_seleniumIDE")).click();

good luck

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

This is simple if you only use Selenium WebDriver, and forget the usage of Selenium-RC. I'd go like this.

WebDriver driver = new FirefoxDriver();
WebElement email = driver.findElement(By.id("email"));
email.sendKeys("[email protected]");

The reason for NullPointerException however is that your variable driver has never been started, you start FirefoxDriver in a variable wb thas is never being used.

Selenium WebDriver findElement(By.xpath()) not working for me

You missed the closing parenthesis at the end:

element = findElement(By.xpath("//[@test-id='test-username']"));

Selenium Webdriver: Entering text into text field

Use this code.

driver.FindElement(By.XPath(".//[@id='header']/div/div[3]/div/form/input[1]")).SendKeys("25025");

Find elements inside forms and iframe using Java and Selenium WebDriver

By using https://github.com/nick318/FindElementInFrames You can find webElement across all frames:

SearchByFramesFactory searchFactory = new SearchByFramesFactory(driver);
SearchByFrames searchInFrame = searchFactory.search(() -> driver.findElement(By.tagName("body")));
Optional<WebElement> elem = searchInFrame.getElem();

How to wait until an element is present in Selenium?

You need to call ignoring with exception to ignore while the WebDriver will wait.

FluentWait<WebDriver> fluentWait = new FluentWait<>(driver)
        .withTimeout(30, TimeUnit.SECONDS)
        .pollingEvery(200, TimeUnit.MILLISECONDS)
        .ignoring(NoSuchElementException.class);

See the documentation of FluentWait for more info. But beware that this condition is already implemented in ExpectedConditions so you should use

WebElement element = (new WebDriverWait(driver, 10))
   .until(ExpectedConditions.elementToBeClickable(By.id("someid")));

*Update for newer versions of Selenium:

withTimeout(long, TimeUnit) has become withTimeout(Duration)
pollingEvery(long, TimeUnit) has become pollingEvery(Duration)

So the code will look as such:

FluentWait<WebDriver> fluentWait = new FluentWait<>(driver)
        .withTimeout(Duration.ofSeconds(30)
        .pollingEvery(Duration.ofMillis(200)
        .ignoring(NoSuchElementException.class);

Basic tutorial for waiting can be found here.

How to get attribute of element from Selenium?

Python

element.get_attribute("attribute name")

Java

element.getAttribute("attribute name")

Ruby

element.attribute("attribute name")

C#

element.GetAttribute("attribute name");

Wait for page load in Selenium

SeleniumWaiter:

import com.google.common.base.Function;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.ui.WebDriverWait;

public class SeleniumWaiter {

      private WebDriver driver;

      public SeleniumWaiter(WebDriver driver) {
           this.driver = driver;
      }

      public WebElement waitForMe(By locatorname, int timeout){
           WebDriverWait wait = new WebDriverWait(driver, timeout);
           return wait.until(SeleniumWaiter.presenceOfElementLocated(locatorname));
      }

      public static Function<WebDriver, WebElement> presenceOfElementLocated(final By locator) {
            // TODO Auto-generated method stub
            return new Function<WebDriver, WebElement>() {
                 @Override
                 public WebElement apply(WebDriver driver) {
                      return driver.findElement(locator);
                 }
            };
      }
 }

And to you use it:

_waiter = new SeleniumWaiter(_driver);

try {
   _waiter.waitForMe(By.xpath("//..."), 10);
} 
catch (Exception e) {
   // Error
}

Fill username and password using selenium in python

In some cases when the element is not interactable, sendKeys() doesn't work and you're likely to encounter an ElementNotInteractableException.

In such cases, you can opt to execute javascript that sets the values and then can post back.

Example:

url = 'https://www.your_url.com/'

driver = Chrome(executable_path="./chromedriver")
driver.get(url)

username = 'your_username'
password = 'your_password'

#Setting the value of email input field
driver.execute_script(f'var element = document.getElementById("email"); element.value = "{username}";')

#Setting the value of password input field
driver.execute_script(f'var element = document.getElementById("password"); element.value = "{password}";')

#Submitting the form or click the login button also
driver.execute_script(f'document.getElementsByClassName("login_form")[0].submit();')

print(driver.page_source)

Reference:

https://www.quora.com/How-do-I-resolve-the-ElementNotInteractableException-in-Selenium-WebDriver

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

To account for leading and trailing whitespace, you probably want to use normalize-space()

//div[contains(@class, 'Caption') and normalize-space(.)='Model saved']

and

//div[@id='alertLabel' and normalize-space(.)='Save to server successful']

Note that //div[contains(@class, 'Caption') and normalize-space(.//text())='Model saved'] also works.

Selenium WebDriver.get(url) does not open the URL

I was having the save issue. I assume you made sure your java server was running before you started your python script? The java server can be downloaded from selenium's download list.

When I did a netstat to evaluate the open ports, i noticed that the java server wasn't running on the specific "localhost" host:

When I started the server, I found that the port number was 4444 :

$ java -jar selenium-server-standalone-2.35.0.jar 
Sep 24, 2013 10:18:57 PM org.openqa.grid.selenium.GridLauncher main
INFO: Launching a standalone server
22:19:03.393 INFO - Java: Apple Inc. 20.51-b01-456
22:19:03.394 INFO - OS: Mac OS X 10.8.5 x86_64
22:19:03.418 INFO - v2.35.0, with Core v2.35.0. Built from revision c916b9d
22:19:03.681 INFO - RemoteWebDriver instances should connect to: http://127.0.0.1:4444/wd/hub
22:19:03.683 INFO - Version Jetty/5.1.x
22:19:03.683 INFO - Started HttpContext[/selenium-server/driver,/selenium-server/driver]
22:19:03.685 INFO - Started HttpContext[/selenium-server,/selenium-server]
22:19:03.685 INFO - Started HttpContext[/,/]
22:19:03.755 INFO - Started org.openqa.jetty.jetty.servlet.ServletHandler@21b64e6a
22:19:03.755 INFO - Started HttpContext[/wd,/wd]
22:19:03.765 INFO - Started SocketListener on 0.0.0.0:4444

I was able to view my listening ports and their port numbers(the -n option) by running the following command in the terminal:

$netstat -an | egrep 'Proto|LISTEN'

This got me the following output

Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)    

tcp46      0      0  *.4444                 *.*                    LISTEN  

I realized this may be a problem, because selenium's socket utils, found in: webdriver/common/utils.py are trying to connect via "localhost" or 127.0.0.1:

socket_.connect(("localhost", port))

once I changed the "localhost" to '' (empty single quotes to represent all local addresses), it started working. So now, the previous line from utils.py looks like this:

socket_.connect(('', port))

I am using MacOs and Firefox 22. The latest version of Firefox at the time of this post is 24, but I heard there are some security issues with the version that may block some of selenium's functionality (I have not verified this). Regardless, for this reason, I am using the older version of Firefox.

Locating child nodes of WebElements in selenium

I also found myself in a similar position a couple of weeks ago. You can also do this by creating a custom ElementLocatorFactory (or simply passing in divA into the DefaultElementLocatorFactory) to see if it's a child of the first div - you would then call the appropriate PageFactory initElements method.

In this case if you did the following:

PageFactory.initElements(new DefaultElementLocatorFactory(divA), pageObjectInstance));
// The Page Object instance would then need a WebElement 
// annotated with something like the xpath above or @FindBy(tagName = "input")

How do I run Selenium in Xvfb?

You can use PyVirtualDisplay (a Python wrapper for Xvfb) to run headless WebDriver tests.

#!/usr/bin/env python

from pyvirtualdisplay import Display
from selenium import webdriver

display = Display(visible=0, size=(800, 600))
display.start()

# now Firefox will run in a virtual display. 
# you will not see the browser.
browser = webdriver.Firefox()
browser.get('http://www.google.com')
print browser.title
browser.quit()

display.stop()

more info


You can also use xvfbwrapper, which is a similar module (but has no external dependencies):

from xvfbwrapper import Xvfb

vdisplay = Xvfb()
vdisplay.start()

# launch stuff inside virtual display here

vdisplay.stop()

or better yet, use it as a context manager:

from xvfbwrapper import Xvfb

with Xvfb() as xvfb:
    # launch stuff inside virtual display here.
    # It starts/stops in this code block.

click command in selenium webdriver does not work

Thanks for all the answers everyone! I have found a solution, turns out I didn't provide enough code in my question.

The problem was NOT with the click() function after all, but instead related to cas authentication used with my project. In Selenium IDE my login test executed a "open" command to the following location,

/cas/login?service=https%1F%8FAPPNAME%2FMOREURL%2Fj_spring_cas_security

That worked. I exported the test to Selenium webdriver which naturally preserved that location. The command in Selenium Webdriver was,

driver.get(baseUrl + "/cas/login?service=https%1A%2F%8FAPPNAME%2FMOREURL%2Fj_spring_cas_security");

For reasons I have yet to understand the above failed. When I changed it to,

driver.get(baseUrl + "MOREURL/");

The click command suddenly started to work... I will edit this answer if I can figure out why exactly this is.

Note: I obscured the URLs used above to protect my company's product.

How to select a drop-down menu value with Selenium using Python?

In this way you can select all the options in any dropdowns.

driver.get("https://www.spectrapremium.com/en/aftermarket/north-america")

print( "The title is  : " + driver.title)

inputs = Select(driver.find_element_by_css_selector('#year'))

input1 = len(inputs.options)

for items in range(input1):

    inputs.select_by_index(items)
    time.sleep(1)

Running javascript in Selenium using Python

If you move from iframes, you may get lost in your page, best way to execute some jquery without issue (with selenimum/python/gecko):

# 1) Get back to the main body page
driver.switch_to.default_content()

# 2) Download jquery lib file to your current folder manually & set path here
with open('./_lib/jquery-3.3.1.min.js', 'r') as jquery_js: 
    # 3) Read the jquery from a file
    jquery = jquery_js.read() 
    # 4) Load jquery lib
    driver.execute_script(jquery)
    # 5) Execute your command 
    driver.execute_script('$("#myId").click()')

Selenium C# WebDriver: Wait until element is present

I confused an anonymous function with a predicate. Here's a little helper method:

   WebDriverWait wait;
    private void waitForById(string id)
    {
        if (wait == null)
            wait = new WebDriverWait(driver, new TimeSpan(0, 0, 5));

        //wait.Until(driver);
        wait.Until(d => d.FindElement(By.Id(id)));
    }

element not interactable exception in selenium web automation

If it's working in the debug, then wait must be the proper solution.
I will suggest to use the explicit wait, as given below:

WebDriverWait wait = new WebDriverWait(new ChromeDriver(), 5);
wait.until(ExpectedConditions.presenceOfElementLocated(By.cssSelector("#Passwd")));

Need to find element in selenium by css

Only using class names is not sufficient in your case.

  • By.cssSelector(".ban") has 15 matching nodes
  • By.cssSelector(".hot") has 11 matching nodes
  • By.cssSelector(".ban.hot") has 5 matching nodes

Therefore you need more restrictions to narrow it down. Option 1 and 2 below are available for css selector, 1 might be the one that suits your needs best.

Option 1: Using list items' index (CssSelector or XPath)

Limitations

  • Not stable enough if site's structure changes

Example:

driver.FindElement(By.CssSelector("#rightbar > .menu > li:nth-of-type(3) > h5"));
driver.FindElement(By.XPath("//*[@id='rightbar']/ul/li[3]/h5"));

Option 2: Using Selenium's FindElements, then index them. (CssSelector or XPath)

Limitations

  • Not stable enough if site's structure changes
  • Not the native selector's way

Example:

// note that By.CssSelector(".ban.hot") and //*[contains(@class, 'ban hot')] are different, but doesn't matter in your case
IList<IWebElement> hotBanners = driver.FindElements(By.CssSelector(".ban.hot"));
IWebElement banUsStates = hotBanners[3];

Option 3: Using text (XPath only)

Limitations

  • Not for multilanguage sites
  • Only for XPath, not for Selenium's CssSelector

Example:

driver.FindElement(By.XPath("//h5[contains(@class, 'ban hot') and text() = 'us states']"));

Option 4: Index the grouped selector (XPath only)

Limitations

  • Not stable enough if site's structure changes
  • Only for XPath, not CssSelector

Example:

driver.FindElement(By.XPath("(//h5[contains(@class, 'ban hot')])[3]"));

Option 5: Find the hidden list items link by href, then traverse back to h5 (XPath only)

Limitations

  • Only for XPath, not CssSelector
  • Low performance
  • Tricky XPath

Example:

driver.FindElement(By.XPath(".//li[.//ul/li/a[contains(@href, 'geo.craigslist.org/iso/us/al')]]/h5"));

What is the difference between cssSelector & Xpath and which is better with respect to performance for cross browser testing?

CSS selectors perform far better than Xpath and it is well documented in Selenium community. Here are some reasons,

  • Xpath engines are different in each browser, hence make them inconsistent
  • IE does not have a native xpath engine, therefore selenium injects its own xpath engine for compatibility of its API. Hence we lose the advantage of using native browser features that WebDriver inherently promotes.
  • Xpath tend to become complex and hence make hard to read in my opinion

However there are some situations where, you need to use xpath, for example, searching for a parent element or searching element by its text (I wouldn't recommend the later).

You can read blog from Simon here . He also recommends CSS over Xpath.

If you are testing content then do not use selectors that are dependent on the content of the elements. That will be a maintenance nightmare for every locale. Try talking with developers and use techniques that they used to externalize the text in the application, like dictionaries or resource bundles etc. Here is my blog that explains it in detail.

edit 1

Thanks to @parishodak, here is the link which provides the numbers proving that CSS performance is better

Selenium WebDriver How to Resolve Stale Element Reference Exception?

Just download new chrome extension and use selenium server 3 it will work fine.

How to select an item from a dropdown list using Selenium WebDriver with java?

To find a particular dropdown box element:

Select gender = new Select(driver.findElement(By.id("gender")));

To get the list of all the elements contained in the dropdown box:

for(int j=1;j<3;j++)
    System.out.println(gender.getOptions().get(j).getText());

To select it through visible text displayed when you click on it:

gender.selectByVisibleText("Male");

To select it by index (starting at 0):

gender.selectByIndex(1);

Using Selenium Web Driver to retrieve value of a HTML input

Following @ragzzy 's answer I use

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

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

It works quite well and does not alter the DOM

Xpath for href element

Below works fine.

//a[@id='oldcontent']

If you've tried certain ones and they haven't worked, then let us know, otherwise something simple like this should work.

Typing the Enter/Return key using Python and Selenium

When you don't want to search any locator, you can use the Robot class. For example,

Robot robot = new Robot();
robot.keyPress(KeyEvent.VK_ENTER);
robot.keyRelease(KeyEvent.VK_ENTER);

Selenium using Python - Geckodriver executable needs to be in PATH

I am using Windows 10 and Anaconda 2. I tried setting the system path variable, but it didn't work out. Then I simply added geckodriver.exe file to the Anaconda 2/Scripts folder and everything works great now.

For me the path was:

C:\Users\Bhavya\Anaconda2\Scripts

Get page title with Selenium WebDriver using Java

In java you can do some thing like:

if(driver.getTitle().contains("some expected text"))
    //Pass
    System.out.println("Page title contains \"some expected text\" ");
else
    //Fail
    System.out.println("Page title doesn't contains \"some expected text\" ");

Selenium Finding elements by class name in python

You can try to get the list of all elements with class = "content" by using find_elements_by_class_name:

a = driver.find_elements_by_class_name("content")

Then you can click on the link that you are looking for.

How to check if an element is visible with WebDriver

Even though I'm somewhat late answering the question:

You can now use WebElement.isDisplayed() to check if an element is visible.

Note:

There are many reasons why an element could be invisible. Selenium tries cover most of them, but there are edge cases where it does not work as expected.

For example, isDisplayed() does return false if an element has display: none or opacity: 0, but at least in my test, it does not reliably detect if an element is covered by another due to CSS positioning.

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

I have posted a similar solution for the same problem,

visit How to use javascript to set attribute of selected web element using selenium Webdriver using java?

Here First we have find the element in my case I have found the element using xpath then we have traverse through the list of elements and then We have cast the driver object to the Executor object and create a script here the first argument is the element and second argument is the property and the third argument is the new value

List<WebElement> unselectableDiv = driver
                .findElements(By.xpath("//div[@class='x-grid3-cell-inner x-grid3-col-6']"));

        for (WebElement element : unselectableDiv) {

            // System.out.println( "**** Checking the size of div "+unselectableDiv.size());

            JavascriptExecutor js = (JavascriptExecutor) driver;

            String scriptSetAttr = "arguments[0].setAttribute(arguments[1],arguments[2])";

            js.executeScript(scriptSetAttr, element, "unselectable", "off");

            System.out.println(" *****   check value of Div property " + element.getAttribute("unselectable"));

        }

Call a Class From another class

If your class2 looks like this having static members

public class2
{
    static int var = 1;

    public static void myMethod()
    {
      // some code

    }
}

Then you can simply call them like

class2.myMethod();
class2.var = 1;

If you want to access non-static members then you would have to instantiate an object.

class2 object = new class2();
object.myMethod();  // non static method
object.var = 1;     // non static variable

How to open a link in new tab (chrome) using Selenium WebDriver?

this below code works for me in Selenium 3 and chrome version 58.

    WebDriver driver = new ChromeDriver();
    driver.get("http://yahoo.com");  
    ((JavascriptExecutor)driver).executeScript("window.open()");
    ArrayList<String> tabs = new ArrayList<String>(driver.getWindowHandles());
    driver.switchTo().window(tabs.get(1));
    driver.get("http://google.com");

Clear text from textarea with selenium

Option a)

If you want to ensure keyboard events are fired, consider using sendKeys(CharSequence).

Example 1:

 from selenium.webdriver.common.keys import Keys
 # ...
 webElement.sendKeys(Keys.CONTROL + "a");
 webElement.sendKeys(Keys.DELETE);

Example 2:

 from selenium.webdriver.common.keys import Keys
 # ...
 webElement.sendKeys(Keys.BACK_SPACE); //do repeatedly, e.g. in while loop

WebElement

There are many ways to get the required WebElement, e.g.:

  • driver.find_element_by_id
  • driver.find_element_by_xpath
  • driver.find_element

Option b)

 webElement.clear();

If this element is a text entry element, this will clear the value.

Note that the events fired by this event may not be as you'd expect. In particular, we don't fire any keyboard or mouse events.

How to save and load cookies using Python + Selenium WebDriver

You can save the current cookies as a Python object using pickle. For example:

import pickle
import selenium.webdriver

driver = selenium.webdriver.Firefox()
driver.get("http://www.google.com")
pickle.dump( driver.get_cookies() , open("cookies.pkl","wb"))

And later to add them back:

import pickle
import selenium.webdriver

driver = selenium.webdriver.Firefox()
driver.get("http://www.google.com")
cookies = pickle.load(open("cookies.pkl", "rb"))
for cookie in cookies:
    driver.add_cookie(cookie)

Python Selenium accessing HTML source

You can simply use the WebDriver object, and access to the page source code via its @property field page_source...

Try this code snippet :-)

from selenium import webdriver
driver = webdriver.Firefox('path/to/executable')
driver.get('https://some-domain.com')
source = driver.page_source
if 'stuff' in source:
    print('found...')
else:
    print('not in source...')

How do I setup the InternetExplorerDriver so it works

public class NavigateUsingAllBrowsers {


public static void main(String[] args) {

WebDriver driverFF= new FirefoxDriver();
driverFF.navigate().to("http://www.firefox.com");


File file =new File("C:/Users/mkv/workspace/ServerDrivers/IEDriverServer.exe");
System.setProperty("webdriver.ie.driver", file.getAbsolutePath());
WebDriver driverIE=new InternetExplorerDriver();
driverIE.navigate().to("http://www.msn.com");

// Download Chrome Driver from http://code.google.com/p/chromedriver/downloads/list

file =new File("C:/Users/mkv/workspace/ServerDrivers/ChromeDriver.exe");
System.setProperty("webdriver.chrome.driver", file.getAbsolutePath());
WebDriver driverChrome=new ChromeDriver();
driverChrome.navigate().to("http://www.chrome.com");

}

}

Webdriver Screenshot

Yes, we have a way to get screenshot extension of .png using python webdriver

use below code if you working in python webriver.it is very simple.

driver.save_screenshot('D\folder\filename.png')

Pressing Ctrl + A in Selenium WebDriver

One more solution (in Java, because you didn't tell us your language - but it works the same way in all languages with Keys class):

String selectAll = Keys.chord(Keys.CONTROL, "a");
driver.findElement(By.whatever("anything")).sendKeys(selectAll);

You can use this to select the whole text in an <input>, or on the whole page (just find the html element and send this to it).


For using Selenium Ruby bindings:

There's no chord() method in the Keys class in Ruby bindings. Therefore, as suggested by Hari Reddy, you'll have to use Selenium Advanced user interactions API, see ActionBuilder:

    driver.action.key_down(:control)
                 .send_keys("a")
                 .key_up(:control)
                 .perform

How to get selenium to wait for ajax response?

I would use

waitForElementPresent(locator)

This will wait until the element is present in the DOM.

If you need to check the element is visible, you may be better using

waitForElementHeight(locator)

How to use XPath preceding-sibling correctly

You don't need to go level up and use .. since all buttons are on the same level:

//button[contains(.,'Arcade Reader')]/preceding-sibling::button[@name='settings']

On Selenium WebDriver how to get Text from Span Tag

You need to locate the element and use getText() method to extract the text.

WebElement element = driver.findElement(By.id("customSelect_3"));
System.out.println(element.getText());

Selenium Error - The HTTP request to the remote WebDriver timed out after 60 seconds

Had same issue with Firefox. I switched over to Chrome with options and all has been fine since.

ChromeOptions options = new ChromeOptions();
 options.AddArgument("no-sandbox");

 ChromeDriver driver = new ChromeDriver(ChromeDriverService.CreateDefaultService(), options, TimeSpan.FromMinutes(3));
 driver.Manage().Timeouts().PageLoad.Add(System.TimeSpan.FromSeconds(30));

IE Driver download location Link for Selenium

Use the below link to download IE Driver latest version

IE Driver

How to read Data from Excel sheet in selenium webdriver

i have used following method to use input data from excel sheet: Need to import following as well

import jxl.Workbook;

then

Workbook wBook = Workbook.getWorkbook(new File("E:\\Testdata\\ShellData.xls"));
//get sheet
jxl.Sheet Sheet = wBook.getSheet(0); 
//Now in application i have given my Username and Password input in following way
driver.findElement(By.xpath("//input[@id='UserName']")).sendKeys(Sheet.getCell(0, i).getContents());
driver.findElement(By.xpath("//input[@id='Password']")).sendKeys(Sheet.getCell(1, i).getContents());
driver.findElement(By.xpath("//input[@name='Login']")).click();

it will Work

WebDriverException: unknown error: DevToolsActivePort file doesn't exist while trying to initiate Chrome Browser

TL;DR: If you are using VirtualBox shared folders, do not create the Chrome profile there!


I ran into this error under Debian 10, but it did not occur under Ubuntu 18.04.

In my Selenium tests, I wanted to install an extension, and use the following Chrome options:

chromeOptions.addArguments(
  `load-extension=${this.extensionDir}`,
  `user-data-dir=${this.profileDir}`,
  `disable-gpu`,
  `no-sandbox`,
  `disable-setuid-sandbox`,
  `disable-dev-shm-usage`,
);

The issue was that I was attempting to create a Chrome profile under a nonstandard directory which was part of a VirtualBox shared folder. Despite using the exact same version of Chrome and Chromedriver, it didn't work under Debian.

The solution was to choose a profile directory somewhere else (e.g. ~/chrome-profile).

Is there any way to start with a POST request using Selenium?

Selenium IDE allows you to run Javascript using storeEval command. Mentioned above solution works fine if you have test page (HTML, not XML) and you need to perform only POST request.

If you need to make POST/PUT/DELETE or any other request then you will need another approach:

XMLHttpRequest!

Example listed below has been tested - all methods (POST/PUT/DELETE) work just fine.

<!--variables-->
<tr>
    <td>store</td>
    <td>/your/target/script.php</td>
    <td>targetUrl</td>
</tr>
<tr>
    <td>store</td>
    <td>user=user1&amp;password</td>
    <td>requestParams</td>
</tr>
<tr>
    <td>store</td>
    <td>POST</td>
    <td>requestMethod</td>
</tr>
<!--scenario-->
<tr>
    <td>storeEval</td>
    <td>window.location.host</td>
    <td>host</td>
</tr>
<tr>
    <td>store</td>
    <td>http://${host}</td>
    <td>baseUrl</td>
</tr>
<tr>
    <td>store</td>
    <td>${baseUrl}${targetUrl}</td>
    <td>absoluteUrl</td>
</tr>
<tr>
    <td>store</td>
    <td>${absoluteUrl}?${requestParams}</td>
    <td>requestUrl</td>
</tr>
<tr>
    <td>storeEval</td>
    <td>var method=storedVars['requestMethod']; var url = storedVars['requestUrl']; loadXMLDoc(url, method); function loadXMLDoc(url, method) { var xmlhttp = new XMLHttpRequest(); xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4) { if(xmlhttp.status==200) { alert(&quot;Results = &quot; + xmlhttp.responseText);} else { alert(&quot;Error!&quot;+ xmlhttp.responseText); }}};&nbsp;&nbsp;xmlhttp.open(method,url,true); xmlhttp.send(); }</td>
    <td></td>
</tr>

Clarification:

${requestParams} - parameters you would like to post (e.g. param1=value1&param2=value3&param1=value3) you may specify as many parameters as you need

${targetUrl} - path to your script (if your have page located at http://domain.com/application/update.php then targetUrl should be equal to /application/update.php)

${requestMethod} - method type (in this particular case it should be "POST" but can be "PUT" or "DELETE" or any other)

How can I generate an HTML report for Junit results?

You can easily do this via ant. Here is a build.xml file for doing this

 <project name="genTestReport" default="gen" basedir=".">
        <description>
                Generate the HTML report from JUnit XML files
        </description>

        <target name="gen">
                <property name="genReportDir" location="${basedir}/unitTestReports"/>
                <delete dir="${genReportDir}"/>
                <mkdir dir="${genReportDir}"/>
                <junitreport todir="${basedir}/unitTestReports">
                        <fileset dir="${basedir}">
                                <include name="**/TEST-*.xml"/>
                        </fileset>
                        <report format="frames" todir="${genReportDir}/html"/>
                </junitreport>
        </target>
</project>

This will find files with the format TEST-*.xml and generate reports into a folder named unitTestReports.

To run this (assuming the above file is called buildTestReports.xml) run the following command in the terminal:

ant -buildfile buildTestReports.xml

Scrolling to element using webdriver?

There is another option to scroll page to required element if element has "id" attribute

If you want to navigate to page and scroll down to element with @id, it can be done automatically by adding #element_id to URL...

Example

Let's say we need to navigate to Selenium Waits documentation and scroll page down to "Implicit Wait" section. We can do

driver.get('https://selenium-python.readthedocs.io/waits.html')

and add code for scrolling...OR use

driver.get('https://selenium-python.readthedocs.io/waits.html#implicit-waits')

to navigate to page AND scroll page automatically to element with id="implicit-waits" (<div class="section" id="implicit-waits">...</div>)

How to make Firefox headless programmatically in Selenium with Python?

from selenium.webdriver.firefox.options import Options

if __name__ == "__main__":
    options = Options()
    options.add_argument('-headless')
    driver = Firefox(executable_path='geckodriver', firefox_options=options) 
    wait = WebDriverWait(driver, timeout=10)
    driver.get('http://www.google.com')

Tested, works as expected and this is from Official - Headless Mode | Mozilla

Selenium WebDriver and DropDown Boxes

Just wrap your WebElement into Select Object as shown below

Select dropdown = new Select(driver.findElement(By.id("identifier")));

Once this is done you can select the required value in 3 ways. Consider an HTML file like this

<html>
<body>
<select id = "designation">
<option value = "MD">MD</option>
<option value = "prog"> Programmer </option>
<option value = "CEO"> CEO </option>
</option>
</select>
<body>
</html>

Now to identify dropdown do

Select dropdown = new Select(driver.findElement(By.id("designation")));

To select its option say 'Programmer' you can do

dropdown.selectByVisibleText("Programmer ");

or

 dropdown.selectByIndex(1);

or

 dropdown.selectByValue("prog");

Happy Coding :)

What is difference between Implicit wait and Explicit wait in Selenium WebDriver?

Check the below links:

  • Implicit Wait - It instructs the web driver to wait for some time by poll the DOM. Once you declared implicit wait it will be available for the entire life of web driver instance. By default the value will be 0. If you set a longer default, then the behavior will poll the DOM on a periodic basis depending on the browser/driver implementation.

  • Explicit Wait + ExpectedConditions - It is the custom one. It will be used if we want the execution to wait for some time until some condition achieved.

Getting list of items inside div using Selenium Webdriver

Follow the code below exactly matched with your case.

  1. Create an interface of the web element for the div under div with class as facetContainerDiv

ie for

<div class="facetContainerDiv">
    <div>

    </div>
</div>

2. Create an IList with all the elements inside the second div i.e for,

<label class="facetLabel">
   <input class="facetCheck" type="checkbox" />
</label>
<label class="facetLabel">
   <input class="facetCheck" type="checkbox" />
</label>
<label class="facetLabel">
   <input class="facetCheck" type="checkbox" />
</label>
<label class="facetLabel">
   <input class="facetCheck" type="checkbox" />
</label>
<label class="facetLabel">
   <input class="facetCheck" type="checkbox" />
</label>

3. Access each check boxes using the index

Please find the code below

using System;
using System.Collections.Generic;
using OpenQA.Selenium;
using OpenQA.Selenium.Firefox;
using OpenQA.Selenium.Support.UI;

namespace SeleniumTests
{
  class ChechBoxClickWthIndex
    {
        static void Main(string[] args)
        {

            IWebDriver driver = new FirefoxDriver();

            driver.Navigate().GoToUrl("file:///C:/Users/chery/Desktop/CheckBox.html");

            // Create an interface WebElement of the div under div with **class as facetContainerDiv**
            IWebElement WebElement =    driver.FindElement(By.XPath("//div[@class='facetContainerDiv']/div"));
            // Create an IList and intialize it with all the elements of div under div with **class as facetContainerDiv**
            IList<IWebElement> AllCheckBoxes = WebElement.FindElements(By.XPath("//label/input"));
            int RowCount = AllCheckBoxes.Count;
            for (int i = 0; i < RowCount; i++)
            {
            // Check the check boxes based on index
               AllCheckBoxes[i].Click();

            }
            Console.WriteLine(RowCount);
            Console.ReadLine(); 

        }
    }
}

How to get text with Selenium WebDriver in Python

You can use:

element = driver.find_element_by_class_name("class_name").text

This will return the text within the element and will allow you to verify it after that.

Open web in new tab Selenium + Python

Strangely, so many answers, and all of them are using surrogates like JS and keyboard shortcuts instead of just using a selenium feature:

def newTab(driver, url="about:blank"):
    wnd = driver.execute(selenium.webdriver.common.action_chains.Command.NEW_WINDOW)
    handle = wnd["value"]["handle"]
    driver.switch_to.window(handle)
    driver.get(url) # changes the handle
    return driver.current_window_handle

Equivalent of waitForVisible/waitForElementPresent in Selenium WebDriver tests using Java?

For individual element the code below could be used:

private boolean isElementPresent(By by) {
        try {
            driver.findElement(by);
            return true;
        } catch (NoSuchElementException e) {
            return false;
        }
    }
for (int second = 0;; second++) {
            if (second >= 60){
                fail("timeout");
            }
            try {
                if (isElementPresent(By.id("someid"))){
                    break;
                }
                }
            catch (Exception e) {

            }
            Thread.sleep(1000);
        }

Selenium WebDriver: Wait for complex page with JavaScript to load

I asked my developers to create a JavaScript variable "isProcessing" that I can access (in the "ae" object) that they set when things start running and clear when things are done. I then run it in an accumulator that checks it every 100 ms until it gets five in a row for a total of 500 ms without any changes. If 30 seconds pass, I throw an exception because something should have happened by then. This is in C#.

public static void WaitForDocumentReady(this IWebDriver driver)
{
    Console.WriteLine("Waiting for five instances of document.readyState returning 'complete' at 100ms intervals.");
    IJavaScriptExecutor jse = (IJavaScriptExecutor)driver;
    int i = 0; // Count of (document.readyState === complete) && (ae.isProcessing === false)
    int j = 0; // Count of iterations in the while() loop.
    int k = 0; // Count of times i was reset to 0.
    bool readyState = false;
    while (i < 5)
    {
        System.Threading.Thread.Sleep(100);
        readyState = (bool)jse.ExecuteScript("return ((document.readyState === 'complete') && (ae.isProcessing === false))");
        if (readyState) { i++; }
        else
        {
            i = 0;
            k++;
        }
        j++;
        if (j > 300) { throw new TimeoutException("Timeout waiting for document.readyState to be complete."); }
    }
    j *= 100;
    Console.WriteLine("Waited " + j.ToString() + " milliseconds. There were " + k + " resets.");
}

ImportError: No module named 'selenium'

I had a similar problem. It turned out that I had an alias defined for python like so:

alias python=/usr/bin/python3

Apparently virtualenv does not check or update your aliases.

So the solution for me was to remove the alias:

unalias python

Now when I run python, I get the one from the virtual environment. Problem solved.

SyntaxError: Use of const in strict mode?

That error means your node's publish is low than the need. carefully to update the node of your computer.

Scroll Element into View with Selenium

I've been doing testing with ADF components and you have to have a separate command for scrolling if lazy loading is used. If the object is not loaded and you attempt to find it using Selenium, Selenium will throw an element-not-found exception.

Webdriver findElements By xpath

Instead of

css=#container

use

css=div.container:nth-of-type(1),css=div.container:nth-of-type(2)

selenium - chromedriver executable needs to be in PATH

An answer from 2020. The following code solves this. A lot of people new to selenium seem to have to get past this step. Install the chromedriver and put it inside a folder on your desktop. Also make sure to put the selenium python project in the same folder as where the chrome driver is located.

Change USER_NAME and FOLDER in accordance to your computer.

For Windows

driver = webdriver.Chrome(r"C:\Users\USER_NAME\Desktop\FOLDER\chromedriver")

For Linux/Mac

driver = webdriver.Chrome("/home/USER_NAME/FOLDER/chromedriver")

What is the meaning of "operator bool() const"

As the others have said, it's for type conversion, in this case to a bool. For example:

class A {
    bool isItSafe;

public:
    operator bool() const
    {
        return isItSafe;
    }

    ...
};

Now I can use an object of this class as if it's a boolean:

A a;
...
if (a) {
    ....
}

What is the difference between Task.Run() and Task.Factory.StartNew()

According to this post by Stephen Cleary, Task.Factory.StartNew() is dangerous:

I see a lot of code on blogs and in SO questions that use Task.Factory.StartNew to spin up work on a background thread. Stephen Toub has an excellent blog article that explains why Task.Run is better than Task.Factory.StartNew, but I think a lot of people just haven’t read it (or don’t understand it). So, I’ve taken the same arguments, added some more forceful language, and we’ll see how this goes. :) StartNew does offer many more options than Task.Run, but it is quite dangerous, as we’ll see. You should prefer Task.Run over Task.Factory.StartNew in async code.

Here are the actual reasons:

  1. Does not understand async delegates. This is actually the same as point 1 in the reasons why you would want to use StartNew. The problem is that when you pass an async delegate to StartNew, it’s natural to assume that the returned task represents that delegate. However, since StartNew does not understand async delegates, what that task actually represents is just the beginning of that delegate. This is one of the first pitfalls that coders encounter when using StartNew in async code.
  2. Confusing default scheduler. OK, trick question time: in the code below, what thread does the method “A” run on?
Task.Factory.StartNew(A);

private static void A() { }

Well, you know it’s a trick question, eh? If you answered “a thread pool thread”, I’m sorry, but that’s not correct. “A” will run on whatever TaskScheduler is currently executing!

So that means it could potentially run on the UI thread if an operation completes and it marshals back to the UI thread due to a continuation as Stephen Cleary explains more fully in his post.

In my case, I was trying to run tasks in the background when loading a datagrid for a view while also displaying a busy animation. The busy animation didn't display when using Task.Factory.StartNew() but the animation displayed properly when I switched to Task.Run().

For details, please see https://blog.stephencleary.com/2013/08/startnew-is-dangerous.html

Regular expression to allow spaces between words

Try with this one:

result = re.search(r"\w+( )\w+", text)

How can I convert a series of images to a PDF from the command line on linux?

Use convert from http://www.imagemagick.org. (Readily supplied as a package in most Linux distributions.)

Java Thread Example?

Here is a simple example:

ThreadTest.java

public class ThreadTest
{
   public static void main(String [] args)
   {
      MyThread t1 = new MyThread(0, 3, 300);
      MyThread t2 = new MyThread(1, 3, 300);
      MyThread t3 = new MyThread(2, 3, 300);

      t1.start();
      t2.start();
      t3.start();
   }
}

MyThread.java

public class MyThread extends Thread
{
   private int startIdx, nThreads, maxIdx;

   public MyThread(int s, int n, int m)
   {
      this.startIdx = s;
      this.nThreads = n;
      this.maxIdx = m;
   }

   @Override
   public void run()
   {
      for(int i = this.startIdx; i < this.maxIdx; i += this.nThreads)
      {
         System.out.println("[ID " + this.getId() + "] " + i);
      }
   }
}

And some output:

[ID 9] 1
[ID 10] 2
[ID 8] 0
[ID 10] 5
[ID 9] 4
[ID 10] 8
[ID 8] 3
[ID 10] 11
[ID 10] 14
[ID 10] 17
[ID 10] 20
[ID 10] 23

An explanation - Each MyThread object tries to print numbers from 0 to 300, but they are only responsible for certain regions of that range. I chose to split it by indices, with each thread jumping ahead by the number of threads total. So t1 does index 0, 3, 6, 9, etc.

Now, without IO, trivial calculations like this can still look like threads are executing sequentially, which is why I just showed the first part of the output. On my computer, after this output thread with ID 10 finishes all at once, followed by 9, then 8. If you put in a wait or a yield, you can see it better:

MyThread.java

System.out.println("[ID " + this.getId() + "] " + i);
Thread.yield();

And the output:

[ID 8] 0
[ID 9] 1
[ID 10] 2
[ID 8] 3
[ID 9] 4
[ID 8] 6
[ID 10] 5
[ID 9] 7

Now you can see each thread executing, giving up control early, and the next executing.

SQL Inner join more than two tables

Here is a general SQL query syntax to join three or more table. This SQL query should work in all major relation database e.g. MySQL, Oracle, Microsoft SQLServer, Sybase and PostgreSQL :

SELECT t1.col, t3.col FROM table1 join table2 ON table1.primarykey = table2.foreignkey
                                  join table3 ON table2.primarykey = table3.foreignkey

We first join table 1 and table 2 which produce a temporary table with combined data from table1 and table2, which is then joined to table3. This formula can be extended for more than 3 tables to N tables, You just need to make sure that SQL query should have N-1 join statement in order to join N tables. like for joining two tables we require 1 join statement and for joining 3 tables we need 2 join statement.

What is the Angular equivalent to an AngularJS $watch?

This behaviour is now part of the component lifecycle.

A component can implement the ngOnChanges method in the OnChanges interface to get access to input changes.

Example:

import {Component, Input, OnChanges} from 'angular2/core';


@Component({
  selector: 'hero-comp',
  templateUrl: 'app/components/hero-comp/hero-comp.html',
  styleUrls: ['app/components/hero-comp/hero-comp.css'],
  providers: [],
  directives: [],

  pipes: [],
  inputs:['hero', 'real']
})
export class HeroComp implements OnChanges{
  @Input() hero:Hero;
  @Input() real:string;
  constructor() {
  }
  ngOnChanges(changes) {
      console.log(changes);
  }
}

Get custom product attributes in Woocommerce

Although @airdrumz solutions works, you will get lots of errors about you doing it wrong by accessing ID directly, this is not good for future compatibility.

But it lead me to inspect the object and create this OOP approach:

function myplug_get_prod_attrs() {
    // Enqueue scripts happens very early, global $product has not been created yet, neither has the post/loop
    global $product;
    $wc_attr_objs = $product->get_attributes();
    $prod_attrs = [];
    foreach ($wc_attr_objs as $wc_attr => $wc_term_objs) {
        $prod_attrs[$wc_attr] = [];
        $wc_terms = $wc_term_objs->get_terms();
        foreach ($wc_terms as $wc_term) {
            array_push($prod_attrs[$wc_attr], $wc_term->slug);
        }
    }
    return $prod_attrs;
}

Bonus, if you are performing the above early before the global $product item is created (e.g. during enqueue scripts), you can make it yourself with:

    $product = wc_get_product(get_queried_object_id());

Creating a comma separated list from IList<string> or IEnumerable<string>

FYI, the .NET 4.0 version of string.Join() has some extra overloads, that work with IEnumerable instead of just arrays, including one that can deal with any type T:

public static string Join(string separator, IEnumerable<string> values)
public static string Join<T>(string separator, IEnumerable<T> values)

How do I do an initial push to a remote repository with Git?

On server:

mkdir my_project.git
cd my_project.git
git --bare init

On client:

mkdir my_project
cd my_project
touch .gitignore
git init
git add .
git commit -m "Initial commit"
git remote add origin [email protected]:/path/to/my_project.git
git push origin master

Note that when you add the origin, there are several formats and schemas you could use. I recommend you see what your hosting service provides.

How to implement a ConfigurationSection with a ConfigurationElementCollection

If you are looking for a custom configuration section like following

<CustomApplicationConfig>
        <Credentials Username="itsme" Password="mypassword"/>
        <PrimaryAgent Address="10.5.64.26" Port="3560"/>
        <SecondaryAgent Address="10.5.64.7" Port="3570"/>
        <Site Id="123" />
        <Lanes>
          <Lane Id="1" PointId="north" Direction="Entry"/>
          <Lane Id="2" PointId="south" Direction="Exit"/>
        </Lanes> 
</CustomApplicationConfig>

then you can use my implementation of configuration section so to get started add System.Configuration assembly reference to your project

Look at the each nested elements I used, First one is Credentials with two attributes so lets add it first

Credentials Element

public class CredentialsConfigElement : System.Configuration.ConfigurationElement
    {
        [ConfigurationProperty("Username")]
        public string Username
        {
            get 
            {
                return base["Username"] as string;
            }
        }

        [ConfigurationProperty("Password")]
        public string Password
        {
            get
            {
                return base["Password"] as string;
            }
        }
    }

PrimaryAgent and SecondaryAgent

Both has the same attributes and seem like a Address to a set of servers for a primary and a failover, so you just need to create one element class for both of those like following

public class ServerInfoConfigElement : ConfigurationElement
    {
        [ConfigurationProperty("Address")]
        public string Address
        {
            get
            {
                return base["Address"] as string;
            }
        }

        [ConfigurationProperty("Port")]
        public int? Port
        {
            get
            {
                return base["Port"] as int?;
            }
        }
    }

I'll explain how to use two different element with one class later in this post, let us skip the SiteId as there is no difference in it. You just have to create one class same as above with one property only. let us see how to implement Lanes collection

it is splitted in two parts first you have to create an element implementation class then you have to create collection element class

LaneConfigElement

public class LaneConfigElement : ConfigurationElement
    {
        [ConfigurationProperty("Id")]
        public string Id
        {
            get
            {
                return base["Id"] as string;
            }
        }

        [ConfigurationProperty("PointId")]
        public string PointId
        {
            get
            {
                return base["PointId"] as string;
            }
        }

        [ConfigurationProperty("Direction")]
        public Direction? Direction
        {
            get
            {
                return base["Direction"] as Direction?;
            }
        }
    }

    public enum Direction
    { 
        Entry,
        Exit
    }

you can notice that one attribute of LanElement is an Enumeration and if you try to use any other value in configuration which is not defined in Enumeration application will throw an System.Configuration.ConfigurationErrorsException on startup. Ok lets move on to Collection Definition

[ConfigurationCollection(typeof(LaneConfigElement), AddItemName = "Lane", CollectionType = ConfigurationElementCollectionType.BasicMap)]
    public class LaneConfigCollection : ConfigurationElementCollection
    {
        public LaneConfigElement this[int index]
        {
            get { return (LaneConfigElement)BaseGet(index); }
            set
            {
                if (BaseGet(index) != null)
                {
                    BaseRemoveAt(index);
                }
                BaseAdd(index, value);
            }
        }

        public void Add(LaneConfigElement serviceConfig)
        {
            BaseAdd(serviceConfig);
        }

        public void Clear()
        {
            BaseClear();
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new LaneConfigElement();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((LaneConfigElement)element).Id;
        }

        public void Remove(LaneConfigElement serviceConfig)
        {
            BaseRemove(serviceConfig.Id);
        }

        public void RemoveAt(int index)
        {
            BaseRemoveAt(index);
        }

        public void Remove(String name)
        {
            BaseRemove(name);
        }

    }

you can notice that I have set the AddItemName = "Lane" you can choose whatever you like for your collection entry item, i prefer to use "add" the default one but i changed it just for the sake of this post.

Now all of our nested Elements have been implemented now we should aggregate all of those in a class which has to implement System.Configuration.ConfigurationSection

CustomApplicationConfigSection

public class CustomApplicationConfigSection : System.Configuration.ConfigurationSection
    {
        private static readonly ILog log = LogManager.GetLogger(typeof(CustomApplicationConfigSection));
        public const string SECTION_NAME = "CustomApplicationConfig";

        [ConfigurationProperty("Credentials")]
        public CredentialsConfigElement Credentials
        {
            get
            {
                return base["Credentials"] as CredentialsConfigElement;
            }
        }

        [ConfigurationProperty("PrimaryAgent")]
        public ServerInfoConfigElement PrimaryAgent
        {
            get
            {
                return base["PrimaryAgent"] as ServerInfoConfigElement;
            }
        }

        [ConfigurationProperty("SecondaryAgent")]
        public ServerInfoConfigElement SecondaryAgent
        {
            get
            {
                return base["SecondaryAgent"] as ServerInfoConfigElement;
            }
        }

        [ConfigurationProperty("Site")]
        public SiteConfigElement Site
        {
            get
            {
                return base["Site"] as SiteConfigElement;
            }
        }

        [ConfigurationProperty("Lanes")]
        public LaneConfigCollection Lanes
        {
            get { return base["Lanes"] as LaneConfigCollection; }
        }
    }

Now you can see that we have two properties with name PrimaryAgent and SecondaryAgent both have the same type now you can easily understand why we had only one implementation class against these two element.

Before you can use this newly invented configuration section in your app.config (or web.config) you just need to tell you application that you have invented your own configuration section and give it some respect, to do so you have to add following lines in app.config (may be right after start of root tag).

<configSections>
    <section name="CustomApplicationConfig" type="MyNameSpace.CustomApplicationConfigSection, MyAssemblyName" />
  </configSections>

NOTE: MyAssemblyName should be without .dll e.g. if you assembly file name is myDll.dll then use myDll instead of myDll.dll

to retrieve this configuration use following line of code any where in your application

CustomApplicationConfigSection config = System.Configuration.ConfigurationManager.GetSection(CustomApplicationConfigSection.SECTION_NAME) as CustomApplicationConfigSection;

I hope above post would help you to get started with a bit complicated kind of custom config sections.

Happy Coding :)

****Edit**** To Enable LINQ on LaneConfigCollection you have to implement IEnumerable<LaneConfigElement>

And Add following implementation of GetEnumerator

public new IEnumerator<LaneConfigElement> GetEnumerator()
        {
            int count = base.Count;
            for (int i = 0; i < count; i++)
            {
                yield return base.BaseGet(i) as LaneConfigElement;
            }
        }

for the people who are still confused about how yield really works read this nice article

Two key points taken from above article are

it doesn’t really end the method’s execution. yield return pauses the method execution and the next time you call it (for the next enumeration value), the method will continue to execute from the last yield return call. It sounds a bit confusing I think… (Shay Friedman)

Yield is not a feature of the .Net runtime. It is just a C# language feature which gets compiled into simple IL code by the C# compiler. (Lars Corneliussen)

react-native :app:installDebug FAILED

I had this issue. Mine worked on the emulator well but it didn't work on the device and the error was

app:installDebug FAILED.

If you have a different app with the same name (or package name) on the device: Rename the app or delete it from your device.

System.BadImageFormatException: Could not load file or assembly

I found a different solution to this issue. Apparently my IIS 7 did not have 32bit mode enabled in my Application Pool by default.

To enable 32bit mode, open IIS and select your Application Pool. Mine was named "ASP.NET v4.0".
Right click, go to "Advanced Settings" and change the section named: "Enabled 32-bit Applications" to true.

Restart your web server and try again.

I found the fix from this blog reference: http://darrell.mozingo.net/2009/01/17/running-iis-7-in-32-bit-mode/

Additionally, you can change the settings on Visual Studio. In my case, I went to Tools > Options > Projects and Solutions > Web Projects and checked Use the 64 bit version of IIS Express for web sites and projects - This was on VS Pro 2015. Nothing else fixed it but this.

Powershell Log Off Remote Session

Below script will work well for both active and disconnected sessions as long as user has access to run logoff command remotely. All you have to do is change the servername from "YourServerName" on 4th line.

param (
    $queryResults = $null,
    [string]$UserName = $env:USERNAME,
    [string]$ServerName = "YourServerName"
)


if (Test-Connection $ServerName -Count 1 -Quiet) {  
    Write-Host "`n`n`n$ServerName is online!" -BackgroundColor Green -ForegroundColor Black


    Write-Host ("`nQuerying Server: `"$ServerName`" for disconnected sessions under UserName: `"" + $UserName.ToUpper() + "`"...") -BackgroundColor Gray -ForegroundColor Black

        query user $UserName /server:$ServerName 2>&1 | foreach {  

            if ($_ -match "Active") {
                Write-Host "Active Sessions"
                $queryResults = ("`n$ServerName," + (($_.trim() -replace ' {2,}', ','))) | ConvertFrom-Csv -Delimiter "," -Header "ServerName","UserName","SessionName","SessionID","CurrentState","IdealTime","LogonTime"


                $queryResults | ft
                Write-Host "Starting logoff procedure..." -BackgroundColor Gray -ForegroundColor Black

                $queryResults | foreach {
                    $Sessionl = $_.SessionID
                    $Serverl = $_.ServerName
                    Write-Host "Logging off"$_.username"from $serverl..." -ForegroundColor black -BackgroundColor Gray
                    sleep 2
                    logoff $Sessionl /server:$Serverl /v

                }


            }                
            elseif ($_ -match "Disc") {
                Write-Host "Disconnected Sessions"
                $queryResults = ("`n$ServerName," + (($_.trim() -replace ' {2,}', ','))) |  ConvertFrom-Csv -Delimiter "," -Header "ServerName","UserName","SessionID","CurrentState","IdealTime","LogonTime"

                $queryResults | ft
                Write-Host "Starting logoff procedure..." -BackgroundColor Gray -ForegroundColor Black

                $queryResults | foreach {
                    $Sessionl = $_.SessionID
                    $Serverl = $_.ServerName
                    Write-Host "Logging off"$_.username"from $serverl..."
                    sleep 2
                    logoff $Sessionl /server:$Serverl /v

                }
            }
            elseif ($_ -match "The RPC server is unavailable") {

                Write-Host "Unable to query the $ServerName, check for firewall settings on $ServerName!" -ForegroundColor White -BackgroundColor Red
            }
            elseif ($_ -match "No User exists for") {Write-Host "No user session exists"}

    }
}
else {

    Write-Host "`n`n`n$ServerName is Offline!" -BackgroundColor red -ForegroundColor white
    Write-Host "Error: Unable to connect to $ServerName!" -BackgroundColor red -ForegroundColor white
    Write-Host "Either the $ServerName is down or check for firewall settings on server $ServerName!" -BackgroundColor Yellow -ForegroundColor black
}





Read-Host "`n`nScript execution finished, press enter to exit!"

Some sample outputs. For active session: enter image description here

For disconnected sessions: enter image description here

if no sessions found: enter image description here Check out this solution as well to query all AD servers for your username and logoff only disconnected sessions. The script will also tell you if there were error connecting or querying the server.

Powershell to find out disconnected RDP session and log off at the same time

List(of String) or Array or ArrayList

Neither collection will let you add items that way.

You can make an extension to make for examle List(Of String) have an Add method that can do that:

Imports System.Runtime.CompilerServices
Module StringExtensions

  <Extension()>
  Public Sub Add(ByVal list As List(Of String), ParamArray values As String())
    For Each s As String In values
      list.Add(s)
    Next
  End Sub

End Module

Now you can add multiple value in one call:

Dim lstOfStrings as New List(Of String)
lstOfStrings.Add(String1, String2, String3, String4)

LaTeX package for syntax highlighting of code in various languages

I recommend Pygments. It accepts a piece of code in any language and outputs syntax highlighted LaTeX code. It uses fancyvrb and color packages to produce its output. I personally prefer it to the listing package. I think fancyvrb creates much prettier results.

Join String list elements with a delimiter in one step

If you just want to log the list of elements, you can use the list toString() method which already concatenates all the list elements.

Remove ALL white spaces from text

Using String.prototype.replace with regex, as mentioned in the other answers, is certainly the best solution.

But, just for fun, you can also remove all whitespaces from a text by using String.prototype.split and String.prototype.join:

_x000D_
_x000D_
const text = ' a b    c d e   f g   ';_x000D_
const newText = text.split(/\s/).join('');_x000D_
_x000D_
console.log(newText); // prints abcdefg
_x000D_
_x000D_
_x000D_

Change NULL values in Datetime format to empty string

This also works:

REPLACE(ISNULL(CONVERT(DATE, @date), ''), '1900-01-01', '') AS 'Your Date Field'

ParseError: not well-formed (invalid token) using cElementTree

After lots of searching through the entire WWW, I only found out that you have to escape certain characters if you want your XML parser to work! Here's how I did it and worked for me:

escape_illegal_xml_characters = lambda x: re.sub(u'[\x00-\x08\x0b\x0c\x0e-\x1F\uD800-\uDFFF\uFFFE\uFFFF]', '', x)

And use it like you'd normally do:

ET.XML(escape_illegal_xml_characters(my_xml_string)) #instead of ET.XML(my_xml_string)

How to test if string exists in file with Bash?

I was looking for a way to do this in the terminal and filter lines in the normal "grep behaviour". Have your strings in a file strings.txt:

string1
string2
...

Then you can build a regular expression like (string1|string2|...) and use it for filtering:

cmd1 | grep -P "($(cat strings.txt | tr '\n' '|' | head -c -1))" | cmd2

Edit: Above only works if you don't use any regex characters, if escaping is required, it could be done like:

cat strings.txt | python3 -c "import re, sys; [sys.stdout.write(re.escape(line[:-1]) + '\n') for line in sys.stdin]" | ...

Print directly from browser without print popup window

This should work, I tried it by myself and it worked for me. If you pass True instead of false, the print dialog will appear.

this.print(false);

How to move child element from one parent to another using jQuery

Based on the answers provided, I decided to make a quick plugin to do this:

(function($){
    $.fn.moveTo = function(selector){
        return this.each(function(){
            var cl = $(this).clone();
            $(cl).appendTo(selector);
            $(this).remove();
        });
    };
})(jQuery);

Usage:

$('#nodeToMove').moveTo('#newParent');

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

Disclaimer: I am the developer of the Gradle Test Logger Plugin.

You can simply use the Gradle Test Logger Plugin to print beautiful logs on the console. The plugin uses sensible defaults to satisfy most users with little or no configuration but also offers a number of themes and configuration options to suit everyone.

Examples

Standard Theme Standard theme

Mocha Theme Mocha theme

Usage

plugins {
    id 'com.adarshr.test-logger' version '<version>'
}

Make sure you always get the latest version from Gradle Central.

Configuration

You don't need any configuration at all. However, the plugin offers a few options. This can be done as follows (default values shown):

testlogger {
    // pick a theme - mocha, standard, plain, mocha-parallel, standard-parallel or plain-parallel
    theme 'standard'

    // set to false to disable detailed failure logs
    showExceptions true

    // set to false to hide stack traces
    showStackTraces true

    // set to true to remove any filtering applied to stack traces
    showFullStackTraces false

    // set to false to hide exception causes
    showCauses true

    // set threshold in milliseconds to highlight slow tests
    slowThreshold 2000

    // displays a breakdown of passes, failures and skips along with total duration
    showSummary true

    // set to true to see simple class names
    showSimpleNames false

    // set to false to hide passed tests
    showPassed true

    // set to false to hide skipped tests
    showSkipped true

    // set to false to hide failed tests
    showFailed true

    // enable to see standard out and error streams inline with the test results
    showStandardStreams false

    // set to false to hide passed standard out and error streams
    showPassedStandardStreams true

    // set to false to hide skipped standard out and error streams
    showSkippedStandardStreams true

    // set to false to hide failed standard out and error streams
    showFailedStandardStreams true
}

I hope you will enjoy using it.

I didn't find "ZipFile" class in the "System.IO.Compression" namespace

you can use an external package if you cant upgrade to 4.5. One such is Ionic.Zip.dll from DotNetZipLib.

using Ionic.Zip;

you can download it here, its free. http://dotnetzip.codeplex.com/

Installing Apple's Network Link Conditioner Tool

Update on the answer December 2019 Xcode 11.1.2

Apple has moved Network Link Conditioner Tool to additional tools for Xcode

Go to the below link

https://developer.apple.com/download/more/?q=Additional%20Tools

enter image description here

Install the dmg file, select hardware from installer

enter image description here

select Network Link conditioner prefpane enter image description here

Execute bash script from URL

bash | curl http://your.url.here/script.txt

actual example:

juan@juan-MS-7808:~$ bash | curl https://raw.githubusercontent.com/JPHACKER2k18/markwe/master/testapp.sh


Oh, wow im alive


juan@juan-MS-7808:~$ 

PHP Remove elements from associative array

Why do not use array_diff?

$array = array(
    1 => 'Awaiting for Confirmation', 
    2 => 'Asssigned', 
    3 => 'In Progress', 
    4 => 'Completed', 
    5 => 'Mark As Spam', 
);
$to_delete = array('Completed', 'Mark As Spam');
$array = array_diff($array, $to_delete);

Just note that your array would be reindexed.

How to change context root of a dynamic web project in Eclipse?

Setting the path to nothing in the Eclipse web modules edit dialog enabled me to access the project without any path component in the URL (i.e. ROOT)

You can reach the web modules edit dialog by pressing F3 if you select Tomcat in the "Servers" view or by double clicking on it.

Some screenshots:

error LNK2038: mismatch detected for '_MSC_VER': value '1600' doesn't match value '1700' in CppFile1.obj

I was importing also some projects from VS2010 to VS 2012. I had the same errors. The errors disappeared when I set back Properties > Config. Properties > General > Platform Toolset to v100 (VS2010). That might not be the correct approach, however.

Sharing a URL with a query string on Twitter

You don't necessarily need to use intent, it you encode your URL it will work with twitter share as well.

How do I determine the size of an object in Python?

Use sys.getsizeof() if you DON'T want to include sizes of linked (nested) objects.

However, if you want to count sub-objects nested in lists, dicts, sets, tuples - and usually THIS is what you're looking for - use the recursive deep sizeof() function as shown below:

import sys
def sizeof(obj):
    size = sys.getsizeof(obj)
    if isinstance(obj, dict): return size + sum(map(sizeof, obj.keys())) + sum(map(sizeof, obj.values()))
    if isinstance(obj, (list, tuple, set, frozenset)): return size + sum(map(sizeof, obj))
    return size

You can also find this function in the nifty toolbox, together with many other useful one-liners:

https://github.com/mwojnars/nifty/blob/master/util.py

module.exports vs exports in Node.js

exports and module.exports are the same unless you reassign exports within your module.

The easiest way to think about it, is to think that this line is implicitly at the top of every module.

var exports = module.exports = {};

If, within your module, you reassign exports, then you reassign it within your module and it no longer equals module.exports. This is why, if you want to export a function, you must do:

module.exports = function() { ... }

If you simply assigned your function() { ... } to exports, you would be reassigning exports to no longer point to module.exports.

If you don't want to refer to your function by module.exports every time, you can do:

module.exports = exports = function() { ... }

Notice that module.exports is the left most argument.

Attaching properties to exports is not the same since you are not reassigning it. That is why this works

exports.foo = function() { ... }

How to convert integer timestamp to Python datetime

datetime.datetime.fromtimestamp() is correct, except you are probably having timestamp in miliseconds (like in JavaScript), but fromtimestamp() expects Unix timestamp, in seconds.

Do it like that:

>>> import datetime
>>> your_timestamp = 1331856000000
>>> date = datetime.datetime.fromtimestamp(your_timestamp / 1e3)

and the result is:

>>> date
datetime.datetime(2012, 3, 16, 1, 0)

Does it answer your question?

EDIT: J.F. Sebastian correctly suggested to use true division by 1e3 (float 1000). The difference is significant, if you would like to get precise results, thus I changed my answer. The difference results from the default behaviour of Python 2.x, which always returns int when dividing (using / operator) int by int (this is called floor division). By replacing the divisor 1000 (being an int) with the 1e3 divisor (being representation of 1000 as float) or with float(1000) (or 1000. etc.), the division becomes true division. Python 2.x returns float when dividing int by float, float by int, float by float etc. And when there is some fractional part in the timestamp passed to fromtimestamp() method, this method's result also contains information about that fractional part (as the number of microseconds).

HTML5 LocalStorage: Checking if a key exists

Quoting from the specification:

The getItem(key) method must return the current value associated with the given key. If the given key does not exist in the list associated with the object then this method must return null.

You should actually check against null.

if (localStorage.getItem("username") === null) {
  //...
}

How to call Stored Procedures with EntityFramework?

This is an example of querying MySQL procedure using Entity Framework

This is the definition of my Stored Procedure in MySQL:

CREATE PROCEDURE GetUpdatedAds (
    IN curChangeTracker BIGINT
    IN PageSize INT
) 
BEGIN
   -- select some recored...
END;

And this is how I query it using Entity Framework:

 var curChangeTracker = new SqlParameter("@curChangeTracker", MySqlDbType.Int64).Value = 0;
 var pageSize = new SqlParameter("@PageSize", (MySqlDbType.Int64)).Value = 100;

 var res = _context.Database.SqlQuery<MyEntityType>($"call GetUpdatedAds({curChangeTracker}, {pageSize})");

Note that I am using C# String Interpolation to build my Query String.

is it possible to add colors to python output?

IDLE's console does not support ANSI escape sequences, or any other form of escapes for coloring your output.

You can learn how to talk to IDLE's console directly instead of just treating it like normal stdout and printing to it (which is how it does things like color-coding your syntax), but that's pretty complicated. The idle documentation just tells you the basics of using IDLE itself, and its idlelib library has no documentation (well, there is a single line of documentation—"(New in 2.3) Support library for the IDLE development environment."—if you know where to find it, but that isn't very helpful). So, you need to either read the source, or do a whole lot of trial and error, to even get started.


Alternatively, you can run your script from the command line instead of from IDLE, in which case you can use whatever escape sequences your terminal handles. Most modern terminals will handle at least basic 16/8-color ANSI. Many will handle 16/16, or the expanded xterm-256 color sequences, or even full 24-bit colors. (I believe gnome-terminal is the default for Ubuntu, and in its default configuration it will handle xterm-256, but that's really a question for SuperUser or AskUbuntu.)

Learning to read the termcap entries to know which codes to enter is complicated… but if you only care about a single console—or are willing to just assume "almost everything handles basic 16/8-color ANSI, and anything that doesn't, I don't care about", you can ignore that part and just hardcode them based on, e.g., this page.

Once you know what you want to emit, it's just a matter of putting the codes in the strings before printing them.

But there are libraries that can make this all easier for you. One really nice library, which comes built in with Python, is curses. This lets you take over the terminal and do a full-screen GUI, with colors and spinning cursors and anything else you want. It is a little heavy-weight for simple uses, of course. Other libraries can be found by searching PyPI, as usual.

Hashcode and Equals for Hashset

I think your questions will all be answered if you understand how Sets, and in particular HashSets work. A set is a collection of unique objects, with Java defining uniqueness in that it doesn't equal anything else (equals returns false).

The HashSet takes advantage of hashcodes to speed things up. It assumes that two objects that equal eachother will have the same hash code. However it does not assume that two objects with the same hash code mean they are equal. This is why when it detects a colliding hash code, it only compares with other objects (in your case one) in the set with the same hash code.

How to use a link to call JavaScript?

just use javascript:---- exemplale

javascript:var JFL_81371678974472 = new JotformFeedback({ formId: '81371678974472', base: 'https://form.jotform.me/', windowTitle: 'Photobook Series', background: '#e44c2a', fontColor: '#FFFFFF', type: 'false', height: 700, width: 500, openOnLoad: true })

Check if a string is a valid date using DateTime.TryParse

Use DateTime.TryParseExact() if you want to match against a specific date format

 string format = "ddd dd MMM h:mm tt yyyy";
DateTime dateTime;
if (DateTime.TryParseExact(dateString, format, CultureInfo.InvariantCulture,
    DateTimeStyles.None, out dateTime))
{
    Console.WriteLine(dateTime);
}
else
{
    Console.WriteLine("Not a date");
}

Download single files from GitHub

You can use curl this way:

curl -OL https://raw.githubusercontent.com/<username>/<repo-name>/<branch-name>/path/to/file

O means that curl downloads the content
L means that curl follows the redirection

How to modify existing XML file with XmlDocument and XmlNode in C#

You need to do something like this:

// instantiate XmlDocument and load XML from file
XmlDocument doc = new XmlDocument();
doc.Load(@"D:\test.xml");

// get a list of nodes - in this case, I'm selecting all <AID> nodes under
// the <GroupAIDs> node - change to suit your needs
XmlNodeList aNodes = doc.SelectNodes("/Equipment/DataCollections/GroupAIDs/AID");

// loop through all AID nodes
foreach (XmlNode aNode in aNodes)
{
   // grab the "id" attribute
   XmlAttribute idAttribute = aNode.Attributes["id"];

   // check if that attribute even exists...
   if (idAttribute != null)
   {
      // if yes - read its current value
      string currentValue = idAttribute.Value;

      // here, you can now decide what to do - for demo purposes,
      // I just set the ID value to a fixed value if it was empty before
      if (string.IsNullOrEmpty(currentValue))
      {
         idAttribute.Value = "515";
      }
   }
}

// save the XmlDocument back to disk
doc.Save(@"D:\test2.xml");

How can I declare dynamic String array in Java

The Array.newInstance(Class<?> componentType, int length) method is to be used to create an array with dynamically length.

Multi-dimensional arrays can be created similarly with the Array.newInstance(Class<?> componentType, int... dimensions) method.

How to use support FileProvider for sharing content to other apps?

In my app FileProvider works just fine, and I am able to attach internal files stored in files directory to email clients like Gmail,Yahoo etc.

In my manifest as mentioned in the Android documentation I placed:

<provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="com.package.name.fileprovider"
        android:grantUriPermissions="true"
        android:exported="false">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/filepaths" />
    </provider>

And as my files were stored in the root files directory, the filepaths.xml were as follows:

 <paths>
<files-path path="." name="name" />

Now in the code:

 File file=new File(context.getFilesDir(),"test.txt");

 Intent shareIntent = new Intent(android.content.Intent.ACTION_SEND_MULTIPLE);

 shareIntent.putExtra(android.content.Intent.EXTRA_SUBJECT,
                                     "Test");

 shareIntent.setType("text/plain");

 shareIntent.putExtra(android.content.Intent.EXTRA_EMAIL,
                                 new String[] {"email-address you want to send the file to"});

   Uri uri = FileProvider.getUriForFile(context,"com.package.name.fileprovider",
                                                   file);

                ArrayList<Uri> uris = new ArrayList<Uri>();
                uris.add(uri);

                shareIntent .putParcelableArrayListExtra(Intent.EXTRA_STREAM,
                                                        uris);


                try {
                   context.startActivity(Intent.createChooser(shareIntent , "Email:").addFlags(Intent.FLAG_ACTIVITY_NEW_TASK));                                                      


                }
                catch(ActivityNotFoundException e) {
                    Toast.makeText(context,
                                   "Sorry No email Application was found",
                                   Toast.LENGTH_SHORT).show();
                }
            }

This worked for me.Hope this helps :)

jQuery AJAX form using mail() PHP script sends email, but POST data from HTML form is undefined

Your PHP script (external file 'email.php') should look like this:

<?php
if($_POST){
    $name = $_POST['name'];
    $email = $_POST['email'];
    $message = $_POST['text'];

//send email
    mail("[email protected]", "51 Deep comment from" .$email, $message);
}
?>

How can I render inline JavaScript with Jade / Pug?

Use the :javascript filter. This will generate a script tag and escape the script contents as CDATA:

!!! 5
html(lang="en")
  head
    title "Test"
    :javascript
      if (10 == 10) {
        alert("working")
      }
  body

Appropriate datatype for holding percent values?

If 2 decimal places is your level of precision, then a "smallint" would handle this in the smallest space (2-bytes). You store the percent multiplied by 100.

EDIT: The decimal type is probably a better match. Then you don't need to manually scale. It takes 5 bytes per value.

How do you show animated GIFs on a Windows Form (c#)

I had the same problem. Whole form (including gif) stopping to redraw itself because of long operation working in the background. Here is how i solved this.

  private void MyThreadRoutine()
  {
   this.Invoke(this.ShowProgressGifDelegate);
   //your long running process
   System.Threading.Thread.Sleep(5000);
   this.Invoke(this.HideProgressGifDelegate);
  }

  private void button1_Click(object sender, EventArgs e)
  {
   ThreadStart myThreadStart = new ThreadStart(MyThreadRoutine);
   Thread myThread = new Thread(myThreadStart);
   myThread.Start(); 
  }

I simply created another thread to be responsible for this operation. Thanks to this initial form continues redrawing without problems (including my gif working). ShowProgressGifDelegate and HideProgressGifDelegate are delegates in form that set visible property of pictureBox with gif to true/false.

JTable won't show column headers

As said in previous answers the 'normal' way is to add it to a JScrollPane, but sometimes you don't want it to scroll (don't ask me when:)). Then you can add the TableHeader yourself. Like this:

JPanel tablePanel = new JPanel(new BorderLayout());
JTable table = new JTable();
tablePanel.add(table, BorderLayout.CENTER);
tablePanel.add(table.getTableHeader(), BorderLayout.NORTH);

Retrofit and GET using parameters

@QueryMap worked for me instead of FieldMap

If you have a bunch of GET params, another way to pass them into your url is a HashMap.

class YourActivity extends Activity {

private static final String BASEPATH = "http://www.example.com";

private interface API {
    @GET("/thing")
    void getMyThing(@QueryMap Map<String, String> params, new Callback<String> callback);
}

public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.your_layout);

   RestAdapter rest = new RestAdapter.Builder().setEndpoint(BASEPATH).build();
   API service = rest.create(API.class);

   Map<String, String> params = new HashMap<String, String>();
   params.put("key1", "val1");
   params.put("key2", "val2");
   // ... as much as you need.

   service.getMyThing(params, new Callback<String>() {
       // ... do some stuff here.
   });
}
}

The URL called will be http://www.example.com/thing/?key1=val1&key2=val2

Replace one character with another in Bash

Use parameter substitution:

string=${string// /.}

When does socket.recv(recv_size) return?

Yes, your conclusion is correct. socket.recv is a blocking call.

socket.recv(1024) will read at most 1024 bytes, blocking if no data is waiting to be read. If you don't read all data, an other call to socket.recv won't block.

socket.recv will also end with an empty string if the connection is closed or there is an error.

If you want a non-blocking socket, you can use the select module (a bit more complicated than just using sockets) or you can use socket.setblocking.

I had issues with socket.setblocking in the past, but feel free to try it if you want.

How to pass anonymous types as parameters?

I think you should make a class for this anonymous type. That'd be the most sensible thing to do in my opinion. But if you really don't want to, you could use dynamics:

public void LogEmployees (IEnumerable<dynamic> list)
{
    foreach (dynamic item in list)
    {
        string name = item.Name;
        int id = item.Id;
    }
}

Note that this is not strongly typed, so if, for example, Name changes to EmployeeName, you won't know there's a problem until runtime.

How to restart adb from root to user mode?

For quick steps just check summary. If interested to know details, go on to read below.

adb is a daemon. Doing ps adb we can see its process.

shell@grouper:/ $ ps adb
USER     PID   PPID  VSIZE  RSS     WCHAN    PC        NAME
shell     133   1     4636   212   ffffffff 00000000 S /sbin/adbd

I just checked what additional property variables it is using when adb is running as root and user.

adb user mode :

shell@grouper:/ $ getprop | grep adb                                         
[init.svc.adbd]: [running]
[persist.sys.usb.config]: [mtp,adb]
[ro.adb.secure]: [1]
[sys.usb.config]: [mtp,adb]
[sys.usb.state]: [mtp,adb]

adb root mode :

shell@grouper:/ # getprop | grep adb                                         
[init.svc.adbd]: [running]
[persist.sys.usb.config]: [mtp,adb]
[ro.adb.secure]: [1]
[service.adb.root]: [1]
[sys.usb.config]: [mtp,adb]
[sys.usb.state]: [mtp,adb]

We can see that service.adb.root is a new prop variable that came up when we did adb root.

So, to change back adb to user from root, I went ahead and made this 0

setprop service.adb.root 0

But this did not change anything.

Then I went ahead and killed the process (with an intention to restart the process). The pid of adbd process in my device is 133

kill -9 133

I exited from shell automatically after I had killed the process.

I did adb shell again it was in user mode.

SUMMARY :

So, we have 3 very simple steps.

  1. Enter adb shell as a root.
  2. setprop service.adb.root 0
  3. kill -9 (pid of adbd)

After these steps just re-enter the shell with adb shell and you are back on your device as a user.

Disable cache for some images

Let's add another solution one to the bunch.

Adding a unique string at the end is a perfect solution.

example.jpg?646413154

Following solution extends this method and provides both the caching capability and fetch a new version when the image is updated.

When the image is updated, the filemtime will be changed.

<?php
$filename = "path/to/images/example.jpg";
$filemtime = filemtime($filename);
?>

Now output the image:

<img src="images/example.jpg?<?php echo $filemtime; ?>" >

How to keep a Python script output window open?

You can just write

input()

at the end of your code

therefore when you run you script it will wait for you to enter something

{ENTER for example}

Creating a copy of a database in PostgreSQL

To clone an existing database with postgres you can do that

/* KILL ALL EXISTING CONNECTION FROM ORIGINAL DB (sourcedb)*/
SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity 
WHERE pg_stat_activity.datname = 'SOURCE_DB' AND pid <> pg_backend_pid();

/* CLONE DATABASE TO NEW ONE(TARGET_DB) */
CREATE DATABASE TARGET_DB WITH TEMPLATE SOURCE_DB OWNER USER_DB;

IT will kill all the connection to the source db avoiding the error

ERROR:  source database "SOURCE_DB" is being accessed by other users

how to convert Lower case letters to upper case letters & and upper case letters to lower case letters

The problem is that you are trying to set the value of SecondTextField after checking every single character in the original string. You should do the conversion "on the side", one character at a time, and only then set the result into the SecondTextField.

As you go through the original string, start composing the output from an empty string. Keep appending the character in the opposite case until you run out of characters. Once the output is ready, set it into SecondTextField.

You can make an output a String, set it to an empty string "", and append characters to it as you go. This will work, but that is an inefficient approach. A better approach would be using a StringBuilder class, which lets you change the string without throwing away the whole thing.

$.focus() not working

if you use bootstrap + modal, this worked for me :

  $(myModal).modal('toggle');
  $(myModal).on('shown.bs.modal', function() {
    $('#modalSearchBox').focus()
  });

Python: AttributeError: '_io.TextIOWrapper' object has no attribute 'split'

Try this:

 >>> f = open('goodlines.txt')
 >>> mylist = f.readlines()

open() function returns a file object. And for file object, there is no method like splitlines() or split(). You could use dir(f) to see all the methods of file object.

React setState not updating state

The setState() operation is asynchronous and hence your console.log() will be executed before the setState() mutates the values and hence you see the result.

To solve it, log the value in the callback function of setState(), like:

setTimeout(() => {
    this.setState({dealersOverallTotal: total},
    function(){
       console.log(this.state.dealersOverallTotal, 'dealersOverallTotal1');
    });
}, 10)

Output array to CSV in Ruby

If you have an array of arrays of data:

rows = [["a1", "a2", "a3"],["b1", "b2", "b3", "b4"], ["c1", "c2", "c3"]]

Then you can write this to a file with the following, which I think is much simpler:

require "csv"
File.write("ss.csv", rows.map(&:to_csv).join)

Converting list to numpy array

If you have a list of lists, you only needed to use ...

import numpy as np
...
npa = np.asarray(someListOfLists, dtype=np.float32)

per this LINK in the scipy / numpy documentation. You just needed to define dtype inside the call to asarray.

ComboBox: Adding Text and Value to an Item (no Binding Source)

This is a very simple solution for windows forms if all is needed is the final value as a (string). The items' names will be displayed on the Combo Box and the selected value can be easily compared.

List<string> items = new List<string>();

// populate list with test strings
for (int i = 0; i < 100; i++)
            items.Add(i.ToString());

// set data source
testComboBox.DataSource = items;

and on the event handler get the value (string) of the selected value

string test = testComboBox.SelectedValue.ToString();

what is trailing whitespace and how can I handle this?

Trailing whitespace is any spaces or tabs after the last non-whitespace character on the line until the newline.

In your posted question, there is one extra space after try:, and there are 12 extra spaces after pass:

>>> post_text = '''\
...             if self.tagname and self.tagname2 in list1:
...                 try: 
...                     question = soup.find("div", "post-text")
...                     title = soup.find("a", "question-hyperlink")
...                     self.list2.append(str(title)+str(question)+url)
...                     current += 1
...                 except AttributeError:
...                     pass            
...             logging.info("%s questions passed, %s questions \
...                 collected" % (count, current))
...             count += 1
...         return self.list2
... '''
>>> for line in post_text.splitlines():
...     if line.rstrip() != line:
...         print(repr(line))
... 
'                try: '
'                    pass            '

See where the strings end? There are spaces before the lines (indentation), but also spaces after.

Use your editor to find the end of the line and backspace. Many modern text editors can also automatically remove trailing whitespace from the end of the line, for example every time you save a file.

How to convert int to string on Arduino?

Here below is a self composed myitoa() which is by far smaller in code, and reserves a FIXED array of 7 (including terminating 0) in char *mystring, which is often desirable. It is obvious that one can build the code with character-shift instead, if one need a variable-length output-string.

void myitoa(int number, char *mystring) {
  boolean negative = number>0;

  mystring[0] = number<0? '-' : '+';
  number = number<0 ? -number : number;
  for (int n=5; n>0; n--) {
     mystring[n] = ' ';
     if(number > 0) mystring[n] = number%10 + 48;
     number /= 10;
  }  
  mystring[6]=0;
}

Jquery - How to make $.post() use contentType=application/json?

I think you may have to

1.Modify the source to make $.post always use JSON data type as it really is just a shortcut for a pre configured $.ajax call

Or

2.Define your own utility function that is a shortcut for the $.ajax configuration you want to use

Or

3.You could overwrite the $.post function with your own implementation via monkey patching.

The JSON datatype in your example refers to the datatype returned from the server and not the format sent to the server.

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

In IntelliJ 2016 and newer you can change this setting from the Help menu, Edit Custom Properties (as commented by @eggplantbr).

On older versions, there's no GUI to do it. But you can change it if you edit the IntelliJ IDEA Platform Properties file:

#---------------------------------------------------------------------
# Maximum file size (kilobytes) IDE should provide code assistance for.
# The larger file is the slower its editor works and higher overall system memory requirements are
# if code assistance is enabled. Remove this property or set to very large number if you need
# code assistance for any files available regardless their size.
#---------------------------------------------------------------------
idea.max.intellisense.filesize=2500

how to customise input field width in bootstrap 3

In Bootstrap 3, .form-control (the class you give your inputs) has a width of 100%, which allows you to wrap them into col-lg-X divs for arrangement. Example from the docs:

<div class="row">
  <div class="col-lg-2">
    <input type="text" class="form-control" placeholder=".col-lg-2">
  </div>
  <div class="col-lg-3">
    <input type="text" class="form-control" placeholder=".col-lg-3">
  </div>
  <div class="col-lg-4">
    <input type="text" class="form-control" placeholder=".col-lg-4">
  </div>
</div>

See under Column sizing.

It's a bit different than in Bootstrap 2.3.2, but you get used to it quickly.

Window.Open with PDF stream instead of PDF location

Note: I have verified this in the latest version of IE, and other browsers like Mozilla and Chrome and this works for me. Hope it works for others as well.

if (data == "" || data == undefined) {
    alert("Falied to open PDF.");
} else { //For IE using atob convert base64 encoded data to byte array
    if (window.navigator && window.navigator.msSaveOrOpenBlob) {
        var byteCharacters = atob(data);
        var byteNumbers = new Array(byteCharacters.length);
        for (var i = 0; i < byteCharacters.length; i++) {
            byteNumbers[i] = byteCharacters.charCodeAt(i);
        }
        var byteArray = new Uint8Array(byteNumbers);
        var blob = new Blob([byteArray], {
            type: 'application/pdf'
        });
        window.navigator.msSaveOrOpenBlob(blob, fileName);
    } else { // Directly use base 64 encoded data for rest browsers (not IE)
        var base64EncodedPDF = data;
        var dataURI = "data:application/pdf;base64," + base64EncodedPDF;
        window.open(dataURI, '_blank');
    }

}

Regular expression matching a multiline block of text

The following is a regular expression matching a multiline block of text:

import re
result = re.findall('(startText)(.+)((?:\n.+)+)(endText)',input)

Why am I getting "void value not ignored as it ought to be"?

The original poster is quoting a GCC compiler error message, but even by reading this thread, it's not clear that the error message is properly addressed - except by @pmg's answer. (+1, btw)


error: void value not ignored as it ought to be

This is a GCC error message that means the return-value of a function is 'void', but that you are trying to assign it to a non-void variable.

Example:

void myFunction()
{
   //...stuff...
}

int main()
{
   int myInt = myFunction(); //Compile error!

    return 0;
}

You aren't allowed to assign void to integers, or any other type.

In the OP's situation:

int a = srand(time(NULL));

...is not allowed. srand(), according to the documentation, returns void.

This question is a duplicate of:

I am responding, despite it being duplicates, because this is the top result on Google for this error message. Because this thread is the top result, it's important that this thread gives a succinct, clear, and easily findable result.

Is there a math nCr function in python?

Do you want iteration? itertools.combinations. Common usage:

>>> import itertools
>>> itertools.combinations('abcd',2)
<itertools.combinations object at 0x01348F30>
>>> list(itertools.combinations('abcd',2))
[('a', 'b'), ('a', 'c'), ('a', 'd'), ('b', 'c'), ('b', 'd'), ('c', 'd')]
>>> [''.join(x) for x in itertools.combinations('abcd',2)]
['ab', 'ac', 'ad', 'bc', 'bd', 'cd']

If you just need to compute the formula, use math.factorial:

import math

def nCr(n,r):
    f = math.factorial
    return f(n) / f(r) / f(n-r)

if __name__ == '__main__':
    print nCr(4,2)

In Python 3, use the integer division // instead of / to avoid overflows:

return f(n) // f(r) // f(n-r)

Output

6

How to create dynamic href in react render function?

Could you please try this ?

Create another item in post such as post.link then assign the link to it before send post to the render function.

post.link = '/posts/+ id.toString();

So, the above render function should be following instead.

return <li key={post.id}><a href={post.link}>{post.title}</a></li>

Apache Server (xampp) doesn't run on Windows 10 (Port 80)

I know that maybe this problem was resolved but I had the same problem with different solution. For that, I am going to explain another possible solution. In my case, the port 80 was occupied by Skype (pid: 25252) and I did not know what programme was.

To see the program's pid which is using the port 80 you can use the command that other people said before:

netstat -aon | findstr 0.0:80

To kill the process using the pid (in the case that you do not know the programme) you have to open the CMD with administrator permission and use the next command:

taskkill /pid 25252

Other options with this command are here.

jQuery - Getting form values for ajax POST

try as this code.

$.ajax({
        type: "POST",
        url: "http://rt.ja.com/includes/register.php?submit=1",
        data: "username="+username+"&email="+email+"&password="+password+"&passconf="+passconf,

        success: function(html)
        {   
            //alert(html);
            $('#userError').html(html);
            $("#userError").html(userChar);
            $("#userError").html(userTaken);
        }
    });

i think this will work definitely..

you can also use .serialize() function for sending data via jquery Ajax..

i.e: data : $("#registerSubmit").serialize()

Thanks.

Returning a promise in an async function in TypeScript

It's complicated.

First of all, in this code

const p = new Promise((resolve) => {
    resolve(4);
});

the type of p is inferred as Promise<{}>. There is open issue about this on typescript github, so arguably this is a bug, because obviously (for a human), p should be Promise<number>.

Then, Promise<{}> is compatible with Promise<number>, because basically the only property a promise has is then method, and then is compatible in these two promise types in accordance with typescript rules for function types compatibility. That's why there is no error in whatever1.

But the purpose of async is to pretend that you are dealing with actual values, not promises, and then you get the error in whatever2 because {} is obvioulsy not compatible with number.

So the async behavior is the same, but currently some workaround is necessary to make typescript compile it. You could simply provide explicit generic argument when creating a promise like this:

const whatever2 = async (): Promise<number> => {
    return new Promise<number>((resolve) => {
        resolve(4);
    });
};

Get the string value from List<String> through loop for display

Answer if you only want to use for each loop ..

for (WebElement s : options) {
    int i = options.indexOf(s);
    System.out.println(options.get(i).getText());
}

Overriding !important style

element.style has a setProperty method that can take the priority as a third parameter:

element.style.setProperty("display", "inline", "important")

It didn't work in old IEs but it should be fine in current browsers.

Can curl make a connection to any TCP ports, not just HTTP/HTTPS?

Yes, it's possible, the syntax is curl [protocol://]<host>[:port], for example:

curl example.com:1234

If you're using Bash, you can also use pseudo-device /dev files to open a TCP connection, e.g.:

exec 5<>/dev/tcp/127.0.0.1/1234
echo "send some stuff" >&5
cat <&5 # Receive some stuff.

See also: More on Using Bash's Built-in /dev/tcp File (TCP/IP).

How to check task status in Celery?

Apart from above Programmatic approach Using Flower Task status can be easily seen.

Real-time monitoring using Celery Events. Flower is a web based tool for monitoring and administrating Celery clusters.

  1. Task progress and history
  2. Ability to show task details (arguments, start time, runtime, and more)
  3. Graphs and statistics

Official Document: Flower - Celery monitoring tool

Installation:

$ pip install flower

Usage:

http://localhost:5555

Is there a way to get a list of column names in sqlite?

I like the answer by @thebeancounter, but prefer to parameterize the unknowns, the only problem being a vulnerability to exploits on the table name. If you're sure it's okay, then this works:

def get_col_names(cursor, tablename):
    """Get column names of a table, given its name and a cursor
       (or connection) to the database.
    """
    reader=cursor.execute("SELECT * FROM {}".format(tablename))
    return [x[0] for x in reader.description] 

If it's a problem, you could add code to sanitize the tablename.

Invalid length for a Base-64 char array

The length of a base64 encoded string is always a multiple of 4. If it is not a multiple of 4, then = characters are appended until it is. A query string of the form ?name=value has problems when the value contains = charaters (some of them will be dropped, I don't recall the exact behavior). You may be able to get away with appending the right number of = characters before doing the base64 decode.

Edit 1

You may find that the value of UserNameToVerify has had "+"'s changed to " "'s so you may need to do something like so:

a = a.Replace(" ", "+");

This should get the length right;

int mod4 = a.Length % 4;
if (mod4 > 0 )
{
    a += new string('=', 4 - mod4);
}

Of course calling UrlEncode (as in LukeH's answer) should make this all moot.

How to delete a folder in C++?

The directory must be empty and your program must have permissions to delete it

but the function called rmdir will do it

rmdir("C:/Documents and Settings/user/Desktop/itsme") 

Remove the newline character in a list read from a file

You want the String.strip(s[, chars]) function, which will strip out whitespace characters or whatever characters (such as '\n') you specify in the chars argument.

See http://docs.python.org/release/2.3/lib/module-string.html

Where are the recorded macros stored in Notepad++?

For Windows 7 macros are stored at C:\Users\Username\AppData\Roaming\Notepad++\shortcuts.xml.

How to get enum value by string or int

Try something like this

  public static TestEnum GetMyEnum(this string title)
        {    
            EnumBookType st;
            Enum.TryParse(title, out st);
            return st;          
         }

So you can do

TestEnum en = "Value1".GetMyEnum();

Intercept and override HTTP requests from WebView

You don't mention the API version, but since API 11 there's the method WebViewClient.shouldInterceptRequest

Maybe this could help?

How to find specified name and its value in JSON-string from Java?

Gson allows for one of the simplest possible solutions. Compared to similar APIs like Jackson or svenson, Gson by default doesn't even need the unused JSON elements to have bindings available in the Java structure. Specific to the question asked, here's a working solution.

import com.google.gson.Gson;

public class Foo
{
  static String jsonInput = 
    "{" + 
      "\"name\":\"John\"," + 
      "\"age\":\"20\"," + 
      "\"address\":\"some address\"," + 
      "\"someobject\":" +
      "{" + 
        "\"field\":\"value\"" + 
      "}" + 
    "}";

  String age;

  public static void main(String[] args) throws Exception
  {
    Gson gson = new Gson();
    Foo thing = gson.fromJson(jsonInput, Foo.class);
    if (thing.age != null)
    {
      System.out.println("age is " + thing.age);
    }
    else
    {
      System.out.println("age element not present or value is null");
    }
  }
}

Logging in Scala

After using slf4s and logula for a while, I wrote loglady, a simple logging trait wrapping slf4j.

It offers an API similar to that of Python's logging library, which makes the common cases (basic string, simple formatting) trivial and avoids formatting boilerplate.

http://github.com/dln/loglady/

Java 8: merge lists with stream API

In Java 8 we can use stream List1.stream().collect(Collectors.toList()).addAll(List2); Another option List1.addAll(List2)

SPAN vs DIV (inline-block)

I know this Q is old, but why not use all DIVs instead of the SPANs? Then everything plays all happy together.

Example:

<div> 
   <div> content1(divs,p, spans, etc) </div> 
   <div> content2(divs,p, spans, etc) </div> 
   <div> content3(divs,p, spans, etc) </div> 
</div> 
<div> 
   <div> content4(divs,p, spans, etc) </div> 
   <div> content5(divs,p, spans, etc) </div> 
   <div> content6(divs,p, spans, etc) </div> 
</div>

Python map object is not subscriptable

map() doesn't return a list, it returns a map object.

You need to call list(map) if you want it to be a list again.

Even better,

from itertools import imap
payIntList = list(imap(int, payList))

Won't take up a bunch of memory creating an intermediate object, it will just pass the ints out as it creates them.

Also, you can do if choice.lower() == 'n': so you don't have to do it twice.

Python supports +=: you can do payIntList[i] += 1000 and numElements += 1 if you want.

If you really want to be tricky:

from itertools import count
for numElements in count(1):
    payList.append(raw_input("Enter the pay amount: "))
    if raw_input("Do you wish to continue(y/n)?").lower() == 'n':
         break

and / or

for payInt in payIntList:
    payInt += 1000
    print payInt

Also, four spaces is the standard indent amount in Python.

How do I implement Cross Domain URL Access from an Iframe using Javascript?

Good article here: Cross-domain communication with iframes

Also you can directly set document.domain the same in both frames (even

document.domain = document.domain;

code has sense because resets port to null), but this trick is not general-purpose.

What is size_t in C?

To go into why size_t needed to exist and how we got here:

In pragmatic terms, size_t and ptrdiff_t are guaranteed to be 64 bits wide on a 64-bit implementation, 32 bits wide on a 32-bit implementation, and so on. They could not force any existing type to mean that, on every compiler, without breaking legacy code.

A size_t or ptrdiff_t is not necessarily the same as an intptr_t or uintptr_t. They were different on certain architectures that were still in use when size_t and ptrdiff_t were added to the Standard in the late ’80s, and becoming obsolete when C99 added many new types but not gone yet (such as 16-bit Windows). The x86 in 16-bit protected mode had a segmented memory where the largest possible array or structure could be only 65,536 bytes in size, but a far pointer needed to be 32 bits wide, wider than the registers. On those, intptr_t would have been 32 bits wide but size_t and ptrdiff_t could be 16 bits wide and fit in a register. And who knew what kind of operating system might be written in the future? In theory, the i386 architecture offers a 32-bit segmentation model with 48-bit pointers that no operating system has ever actually used.

The type of a memory offset could not be long because far too much legacy code assumes that long is exactly 32 bits wide. This assumption was even built into the UNIX and Windows APIs. Unfortunately, a lot of other legacy code also assumed that a long is wide enough to hold a pointer, a file offset, the number of seconds that have elapsed since 1970, and so on. POSIX now provides a standardized way to force the latter assumption to be true instead of the former, but neither is a portable assumption to make.

It couldn’t be int because only a tiny handful of compilers in the ’90s made int 64 bits wide. Then they really got weird by keeping long 32 bits wide. The next revision of the Standard declared it illegal for int to be wider than long, but int is still 32 bits wide on most 64-bit systems.

It couldn’t be long long int, which anyway was added later, since that was created to be at least 64 bits wide even on 32-bit systems.

So, a new type was needed. Even if it weren’t, all those other types meant something other than an offset within an array or object. And if there was one lesson from the fiasco of 32-to-64-bit migration, it was to be specific about what properties a type needed to have, and not use one that meant different things in different programs.

Python, Matplotlib, subplot: How to set the axis range?

If you know the exact axis you want, then

pylab.ylim([0,1000])

works as answered previously. But if you want a more flexible axis to fit your exact data, as I did when I found this question, then set axis limit to be the length of your dataset. If your dataset is fft as in the question, then add this after your plot command:

length = (len(fft)) pylab.ylim([0,length])

Search an Oracle database for tables with specific column names?

Here is one that we have saved off to findcol.sql so we can run it easily from within SQLPlus

set verify off
clear break
accept colnam prompt 'Enter Column Name (or part of): '
set wrap off
select distinct table_name, 
                column_name, 
                data_type || ' (' || 
                decode(data_type,'LONG',null,'LONG RAW',null,
                       'BLOB',null,'CLOB',null,'NUMBER',
                       decode(data_precision,null,to_char(data_length),
                              data_precision||','||data_scale
                             ), data_length
                      ) || ')' data_type
  from all_tab_columns
 where column_name like ('%' || upper('&colnam') || '%');
set verify on

Creation timestamp and last update timestamp with Hibernate and MySQL

A good approach is to have a common base class for all your entities. In this base class, you can have your id property if it is commonly named in all your entities (a common design), your creation and last update date properties.

For the creation date, you simply keep a java.util.Date property. Be sure, to always initialize it with new Date().

For the last update field, you can use a Timestamp property, you need to map it with @Version. With this Annotation the property will get updated automatically by Hibernate. Beware that Hibernate will also apply optimistic locking (it's a good thing).

What is the use of static constructors?

Why and when would we create a static constructor ...?

One specific reason to use a static constructor is to create a 'super enum' class. Here's a (simple, contrived) example:

public class Animals
{
    private readonly string _description;
    private readonly string _speciesBinomialName;

    public string Description { get { return _description; } }
    public string SpeciesBinomialName { get { return _speciesBinomialName; } }

    private Animals(string description, string speciesBinomialName)
    {
        _description = description;
        _speciesBinomialName = speciesBinomialName;
    }

    private static readonly Animals _dog;
    private static readonly Animals _cat;
    private static readonly Animals _boaConstrictor;

    public static Animals Dog { get { return _dog; } }
    public static Animals Cat { get { return _cat; } }
    public static Animals BoaConstrictor { get { return _boaConstrictor; } }

    static Animals()
    {
        _dog = new Animals("Man's best friend", "Canis familiaris");
        _cat = new Animals("Small, typically furry, killer", "Felis catus");
        _boaConstrictor = new Animals("Large, heavy-bodied snake", "Boa constrictor");
    }
}

You'd use it very similarly (in syntactical appearance) to any other enum:

Animals.Dog

The advantage of this over a regular enum is that you can encapsulate related info easily. One disadvantage is that you can't use these values in a switch statement (because it requires constant values).

Error: Could not find or load main class

If you are using Eclipse... I renamed my main class file and got that error. I went to "Run As" configurator and under the class path for that project, it had listed both files in the class path. I removed old class that I renamed and left the class that had the new name and it compiled and ran just fine.

Number of visitors on a specific page

As Blexy already answered, go to "Behavior > Site Content > All Pages".

Just pay attention that "Behavior" appears two times in the left sidebar and we need to click on the second option:

                                                     sidebar

Java POI : How to read Excel cell value and not the formula computing it?

SelThroughJava's answer was very helpful I had to modify a bit to my code to be worked . I used https://mvnrepository.com/artifact/org.apache.poi/poi and https://mvnrepository.com/artifact/org.testng/testng as dependencies . Full code is given below with exact imports.

 import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;

    import org.apache.poi.hssf.usermodel.HSSFCell;
    import org.apache.poi.hssf.util.CellReference;
    import org.apache.poi.sl.usermodel.Sheet;
    import org.apache.poi.ss.usermodel.Cell;
    import org.apache.poi.ss.usermodel.CellType;
    import org.apache.poi.ss.usermodel.CellValue;
    import org.apache.poi.ss.usermodel.FormulaEvaluator;
    import org.apache.poi.ss.usermodel.Row;
    import org.apache.poi.ss.usermodel.Workbook;
    import org.apache.poi.ss.usermodel.WorkbookFactory;
    import org.apache.poi.xssf.usermodel.XSSFWorkbook;


    public class ReadExcelFormulaValue {

        private static final CellType NUMERIC = null;
        public static void main(String[] args) {
            try {
                readFormula();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        public static void readFormula() throws IOException {
            FileInputStream fis = new FileInputStream("C:eclipse-workspace\\sam-webdbriver-diaries\\resources\\tUser_WS.xls");
            org.apache.poi.ss.usermodel.Workbook workbook = WorkbookFactory.create(fis);
            org.apache.poi.ss.usermodel.Sheet sheet = workbook.getSheetAt(0);

            FormulaEvaluator evaluator = workbook.getCreationHelper().createFormulaEvaluator();

            CellReference cellReference = new CellReference("G2"); // pass the cell which contains the formula
            Row row = sheet.getRow(cellReference.getRow());
            Cell cell = row.getCell(cellReference.getCol());

            CellValue cellValue = evaluator.evaluate(cell);
            System.out.println("Cell type month  is "+cellValue.getCellTypeEnum());
            System.out.println("getNumberValue month is  "+cellValue.getNumberValue());     
          //  System.out.println("getStringValue "+cellValue.getStringValue());


            cellReference = new CellReference("H2"); // pass the cell which contains the formula
             row = sheet.getRow(cellReference.getRow());
             cell = row.getCell(cellReference.getCol());

            cellValue = evaluator.evaluate(cell);
            System.out.println("getNumberValue DAY is  "+cellValue.getNumberValue());    


        }

    }

SVN Commit failed, access forbidden

You can get the "Forbidden" error if your user account lacks access permissions to a repository or repository path; it makes sense to check authorization settings for your user account. Make sure your system administrator hasn't provided you with No Access permission to the repository path.

If you are sure that permissions are set correctly, then double-check the URL you use. URLs in Apache Subversion are case-sensitive.

Additionally, I advise you to read articles on authorization in Subversion and VisualSVN Server:

Bootstrap: how do I change the width of the container?

For bootstrap 4 if you are using Sass here is the variable to edit

// Grid containers
//
// Define the maximum width of `.container` for different screen sizes.

$container-max-widths: (
  sm: 540px,
  md: 720px,
  lg: 960px,
  xl: 1140px
) !default;

To override this variable I declared $container-max-widths without the !default in my .sass file before importing bootstrap.

Note : I only needed to change the xl value so I didn't care to think about breakpoints.

Counting the number of occurences of characters in a string

I think what you are looking for is this:

public class Ques2 {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String input = br.readLine().toLowerCase();
    StringBuilder result = new StringBuilder();
    char currentCharacter;
    int count;

    for (int i = 0; i < input.length(); i++) {
        currentCharacter = input.charAt(i);
        count = 1;
        while (i < input.length() - 1 && input.charAt(i + 1) == currentCharacter) {
            count++;
            i++;
        }
        result.append(currentCharacter);
        result.append(count);
    }

    System.out.println("" + result);
}

}

Warning: mysql_connect(): Access denied for user 'root'@'localhost' (using password: YES)

try $conn = mysql_connect("localhost", "root") or $conn = mysql_connect("localhost", "root", "")

Subset dataframe by multiple logical conditions of rows to remove

sub.data<-data[ data[,1] != "b"  & data[,1] != "d" & data[,1] != "e" , ]

Larger but simple to understand (I guess) and can be used with multiple columns, even with !is.na( data[,1]).

Jquery AJAX: No 'Access-Control-Allow-Origin' header is present on the requested resource

I have added dataType: 'jsonp' and it works!

$.ajax({
   type: 'POST',
   crossDomain: true,
   dataType: 'jsonp',
   url: '',
   success: function(jsondata){

   }
})

JSONP is a method for sending JSON data without worrying about cross-domain issues. Read More

Getting unix timestamp from Date()

Use SimpleDateFormat class. Take a look on its javadoc: it explains how to use format switches.

Remove Project from Android Studio

File > Close Project

move your mouse cursor on the project and press Delete keyboard button :)

EDIT try this solution, works for me

How to access parameters in a RESTful POST method

Your @POST method should be accepting a JSON object instead of a string. Jersey uses JAXB to support marshaling and unmarshaling JSON objects (see the jersey docs for details). Create a class like:

@XmlRootElement
public class MyJaxBean {
    @XmlElement public String param1;
    @XmlElement public String param2;
}

Then your @POST method would look like the following:

@POST @Consumes("application/json")
@Path("/create")
public void create(final MyJaxBean input) {
    System.out.println("param1 = " + input.param1);
    System.out.println("param2 = " + input.param2);
}

This method expects to receive JSON object as the body of the HTTP POST. JAX-RS passes the content body of the HTTP message as an unannotated parameter -- input in this case. The actual message would look something like:

POST /create HTTP/1.1
Content-Type: application/json
Content-Length: 35
Host: www.example.com

{"param1":"hello","param2":"world"}

Using JSON in this way is quite common for obvious reasons. However, if you are generating or consuming it in something other than JavaScript, then you do have to be careful to properly escape the data. In JAX-RS, you would use a MessageBodyReader and MessageBodyWriter to implement this. I believe that Jersey already has implementations for the required types (e.g., Java primitives and JAXB wrapped classes) as well as for JSON. JAX-RS supports a number of other methods for passing data. These don't require the creation of a new class since the data is passed using simple argument passing.


HTML <FORM>

The parameters would be annotated using @FormParam:

@POST
@Path("/create")
public void create(@FormParam("param1") String param1,
                   @FormParam("param2") String param2) {
    ...
}

The browser will encode the form using "application/x-www-form-urlencoded". The JAX-RS runtime will take care of decoding the body and passing it to the method. Here's what you should see on the wire:

POST /create HTTP/1.1
Host: www.example.com
Content-Type: application/x-www-form-urlencoded;charset=UTF-8
Content-Length: 25

param1=hello&param2=world

The content is URL encoded in this case.

If you do not know the names of the FormParam's you can do the following:

@POST @Consumes("application/x-www-form-urlencoded")
@Path("/create")
public void create(final MultivaluedMap<String, String> formParams) {
    ...
}

HTTP Headers

You can using the @HeaderParam annotation if you want to pass parameters via HTTP headers:

@POST
@Path("/create")
public void create(@HeaderParam("param1") String param1,
                   @HeaderParam("param2") String param2) {
    ...
}

Here's what the HTTP message would look like. Note that this POST does not have a body.

POST /create HTTP/1.1
Content-Length: 0
Host: www.example.com
param1: hello
param2: world

I wouldn't use this method for generalized parameter passing. It is really handy if you need to access the value of a particular HTTP header though.


HTTP Query Parameters

This method is primarily used with HTTP GETs but it is equally applicable to POSTs. It uses the @QueryParam annotation.

@POST
@Path("/create")
public void create(@QueryParam("param1") String param1,
                   @QueryParam("param2") String param2) {
    ...
}

Like the previous technique, passing parameters via the query string does not require a message body. Here's the HTTP message:

POST /create?param1=hello&param2=world HTTP/1.1
Content-Length: 0
Host: www.example.com

You do have to be particularly careful to properly encode query parameters on the client side. Using query parameters can be problematic due to URL length restrictions enforced by some proxies as well as problems associated with encoding them.


HTTP Path Parameters

Path parameters are similar to query parameters except that they are embedded in the HTTP resource path. This method seems to be in favor today. There are impacts with respect to HTTP caching since the path is what really defines the HTTP resource. The code looks a little different than the others since the @Path annotation is modified and it uses @PathParam:

@POST
@Path("/create/{param1}/{param2}")
public void create(@PathParam("param1") String param1,
                   @PathParam("param2") String param2) {
    ...
}

The message is similar to the query parameter version except that the names of the parameters are not included anywhere in the message.

POST /create/hello/world HTTP/1.1
Content-Length: 0
Host: www.example.com

This method shares the same encoding woes that the query parameter version. Path segments are encoded differently so you do have to be careful there as well.


As you can see, there are pros and cons to each method. The choice is usually decided by your clients. If you are serving FORM-based HTML pages, then use @FormParam. If your clients are JavaScript+HTML5-based, then you will probably want to use JAXB-based serialization and JSON objects. The MessageBodyReader/Writer implementations should take care of the necessary escaping for you so that is one fewer thing that can go wrong. If your client is Java based but does not have a good XML processor (e.g., Android), then I would probably use FORM encoding since a content body is easier to generate and encode properly than URLs are. Hopefully this mini-wiki entry sheds some light on the various methods that JAX-RS supports.

Note: in the interest of full disclosure, I haven't actually used this feature of Jersey yet. We were tinkering with it since we have a number of JAXB+JAX-RS applications deployed and are moving into the mobile client space. JSON is a much better fit that XML on HTML5 or jQuery-based solutions.

The following classes could not be instantiated: - android.support.v7.widget.Toolbar

For Android Studio (or IntelliJ IDEA),

If everything looks OK in your project and that you're still receiving the error in all your layouts, try to 'Invalidate caches & restart'.

Wait until Android Studio has finished to create all the caches & indexes.

how to invalidate cache & restart

Show a div with Fancybox

You just use this and it will be helpful for you

$("#btnForm").click(function (){

$.fancybox({
    'padding':  0,
    'width':    1087,
    'height':   610,
    'type':     'iframe',
    content:   $('#divForm').show();
        });

});

How to get span tag inside a div in jQuery and assign a text?

Try this

$("#message span").text("hello world!");

function Errormessage(txt) {
    var elem = $("#message");
    elem.fadeIn("slow");
    // find the span inside the div and assign a text
    elem.children("span").text("your text");

    elem.children("a.close-notify").click(function() {
        elem.fadeOut("slow");
    });
}

Sum of Numbers C++

First, you have two variables of the same name i. This calls for confusion.

Second, you should declare a variable called sum, which is initially zero. Then, in a loop, you should add to it the numbers from 1 upto and including positiveInteger. After that, you should output the sum.

Print Pdf in C#

The easiest way is to create C# Process and launch external tool to print your PDF file

private static void ExecuteRawFilePrinter() {
    Process process = new Process();
    process.StartInfo.FileName = "c:\\Program Files (x86)\\RawFilePrinter\\RawFilePrinter.exe";
    process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
    process.StartInfo.Arguments = string.Format("-p \"c:\\Users\\Me\\Desktop\\mypdffile.pdf\" \"gdn02ptr006\"");
    process.Start();
    process.WaitForExit();
}

Code above launches RawFilePrinter.exe (similar to 2Printer.exe), but with better support. It is not free, but by making donation allow you to use it everywhere and redistribute with your application. Latest version to download: http://bigdotsoftware.pl/rawfileprinter

Filter an array using a formula (without VBA)

This will do it if you only want the first "B" value, you can sub a cell address for "B" if you want to make it more generic.

=INDEX(A2:A6,SUMPRODUCT(MATCH(TRUE,(B2:B6)="B",0)),1)

To use this based on two columns, just concatenate inside the match:

=INDEX(A2:A6,SUMPRODUCT(MATCH(TRUE,(A2:A6&B2:B6)=("3"&"B"),0)),1)

Sum up a column from a specific row down

You all seem to love complication. Just click on column(to select entire column), press and hold CTRL and click on cells that you want to exclude(C1 to C5 in you case). Now you have selected entire column C (right to the end of sheet) without starting cells. All you have to do now is to rightclick and "Define Name" for your selection(ex. asdf ). In formula you use SUM(asdf). And now you're done. Good luck

Allways find the easyest way ;)

Python: How to check a string for substrings from a list?

Try this test:

any(substring in string for substring in substring_list)

It will return True if any of the substrings in substring_list is contained in string.

Note that there is a Python analogue of Marc Gravell's answer in the linked question:

from itertools import imap
any(imap(string.__contains__, substring_list)) 

In Python 3, you can use map directly instead:

any(map(string.__contains__, substring_list))

Probably the above version using a generator expression is more clear though.

Express.js - app.listen vs server.listen

Express is basically a wrapper of http module that is created for the ease of the developers in such a way that..

  1. They can set up middlewares to respond to HTTP Requests (easily) using express.
  2. They can dynamically render HTML Pages based on passing arguments to templates using express.
  3. They can also define routing easily using express.

MySQL COUNT DISTINCT

 Select
     Count(Distinct user_id) As countUsers
   , Count(site_id) As countVisits
   , site_id As site
 From cp_visits
 Where ts >= DATE_SUB(NOW(), INTERVAL 1 DAY)
 Group By site_id

Programmatically go back to the previous fragment in the backstack

Add those line to your onBackPressed() Method. popBackStackImmediate() method will get you back to the previous fragment if you have any fragment on back stack `

if(getFragmentManager().getBackStackEntryCount() > 0){
     getFragmentManager().popBackStackImmediate();
}
else{
    super.onBackPressed();
}

`

A required class was missing while executing org.apache.maven.plugins:maven-war-plugin:2.1.1:war

Does the class org.apache.maven.shared.filtering.MavenFilteringException exist in file:/C:/Users/utopcu/.m2/repository/org/apache/maven/shared/maven-filtering/1.0-beta-2/maven-filtering-1.0-beta-2.jar?

The error message suggests that it doesn't. Maybe the JAR was corrupted somehow.

I'm also wondering where the version 1.0-beta-2 comes from; I have 1.0 on my disk. Try version 2.3 of the WAR plugin.

difference between $query>num_rows() and $this->db->count_all_results() in CodeIgniter & which one is recommended

$this->db->count_all_results is part of an Active Record query (preparing the query, to only return the number, not the actual results).

$query->num_rows() is performed on a resultset object (after returning results from the DB).

Plotting histograms from grouped data in a pandas DataFrame

I'm on a roll, just found an even simpler way to do it using the by keyword in the hist method:

df['N'].hist(by=df['Letter'])

That's a very handy little shortcut for quickly scanning your grouped data!

For future visitors, the product of this call is the following chart: enter image description here

How to make several plots on a single page using matplotlib?

The answer from las3rjock, which somehow is the answer accepted by the OP, is incorrect--the code doesn't run, nor is it valid matplotlib syntax; that answer provides no runnable code and lacks any information or suggestion that the OP might find useful in writing their own code to solve the problem in the OP.

Given that it's the accepted answer and has already received several up-votes, I suppose a little deconstruction is in order.

First, calling subplot does not give you multiple plots; subplot is called to create a single plot, as well as to create multiple plots. In addition, "changing plt.figure(i)" is not correct.

plt.figure() (in which plt or PLT is usually matplotlib's pyplot library imported and rebound as a global variable, plt or sometimes PLT, like so:

from matplotlib import pyplot as PLT

fig = PLT.figure()

the line just above creates a matplotlib figure instance; this object's add_subplot method is then called for every plotting window (informally think of an x & y axis comprising a single subplot). You create (whether just one or for several on a page), like so

fig.add_subplot(111)

this syntax is equivalent to

fig.add_subplot(1,1,1)

choose the one that makes sense to you.

Below I've listed the code to plot two plots on a page, one above the other. The formatting is done via the argument passed to add_subplot. Notice the argument is (211) for the first plot and (212) for the second.

from matplotlib import pyplot as PLT

fig = PLT.figure()

ax1 = fig.add_subplot(211)
ax1.plot([(1, 2), (3, 4)], [(4, 3), (2, 3)])

ax2 = fig.add_subplot(212)
ax2.plot([(7, 2), (5, 3)], [(1, 6), (9, 5)])

PLT.show()

Each of these two arguments is a complete specification for correctly placing the respective plot windows on the page.

211 (which again, could also be written in 3-tuple form as (2,1,1) means two rows and one column of plot windows; the third digit specifies the ordering of that particular subplot window relative to the other subplot windows--in this case, this is the first plot (which places it on row 1) hence plot number 1, row 1 col 1.

The argument passed to the second call to add_subplot, differs from the first only by the trailing digit (a 2 instead of a 1, because this plot is the second plot (row 2, col 1).

An example with more plots: if instead you wanted four plots on a page, in a 2x2 matrix configuration, you would call the add_subplot method four times, passing in these four arguments (221), (222), (223), and (224), to create four plots on a page at 10, 2, 8, and 4 o'clock, respectively and in this order.

Notice that each of the four arguments contains two leadings 2's--that encodes the 2 x 2 configuration, ie, two rows and two columns.

The third (right-most) digit in each of the four arguments encodes the ordering of that particular plot window in the 2 x 2 matrix--ie, row 1 col 1 (1), row 1 col 2 (2), row 2 col 1 (3), row 2 col 2 (4).

Where does the .gitignore file belong?

As the other answers stated, you can place .gitignore within any directory in a Git repository. However, if you need to have a private version of .gitignore, you can add the rules to .git/info/exclude file.

How to Logout of an Application Where I Used OAuth2 To Login With Google?

This works to sign the user out of the application, but not Google.

var auth2 = gapi.auth2.getAuthInstance();
auth2.signOut().then(function () {
  console.log('User signed out.');
});

Source: https://developers.google.com/identity/sign-in/web/sign-in

Converting an array to a function arguments list

Yes. In current versions of JS you can use:

app[func]( ...args );

Users of ES5 and older will need to use the .apply() method:

app[func].apply( this, args );

Read up on these methods at MDN:

Simplest JQuery validation rules example

$("#commentForm").validate({
    rules: {
     cname : { required : true, minlength: 2 }
    }
});

Should be something like that, I've just typed this up in the editor here so might be a syntax error or two, but you should be able to follow the pattern and the documentation

Self-reference for cell, column and row in worksheet functions

My current Column is calculated by:

Method 1:

=LEFT(ADDRESS(ROW(),COLUMN(),4,1),LEN(ADDRESS(ROW(),COLUMN(),4,1))-LEN(ROW()))

Method 2:

=LEFT(ADDRESS(ROW(),COLUMN(),4,1),INT((COLUMN()-1)/26)+1)

My current Row is calculated by:

=RIGHT(ADDRESS(ROW(),COLUMN(),4,1),LEN(ROW()))

so an indirect link to Sheet2!My Column but a different row, specified in Column A on my row is:

Method 1:

=INDIRECT("Sheet2!"&LEFT(ADDRESS(ROW(),COLUMN(),4,1),LEN(ADDRESS(ROW(),COLUMN(),4,1))-LEN(ROW()))&INDIRECT(ADDRESS(ROW(),1,4,1)))

Method 2:

=INDIRECT("Sheet2!"&LEFT(ADDRESS(ROW(),COLUMN(),4,1),INT((COLUMN()-1)/26)+1)&INDIRECT(ADDRESS(ROW(),1,4,1)))

So if A6=3 and my row is 6 and my Col is C returns contents of "Sheet2!C3"

So if A7=1 and my row is 7 and my Col is D returns contents of "Sheet2!D1"

How to construct a set out of list items in python?

The most direct solution is this:

s = set(filelist)

The issue in your original code is that the values weren't being assigned to the set. Here's the fixed-up version of your code:

s = set()
for filename in filelist:
    s.add(filename)
print(s)

Copy table without copying data

Try:

CREATE TABLE foo SELECT * FROM bar LIMIT 0

Or:

CREATE TABLE foo SELECT * FROM bar WHERE 1=0

How to Run a jQuery or JavaScript Before Page Start to Load

If you don't want anything to display before the redirect, then you will need to use some server side scripting to accomplish the task before the page is served. The page has already begun loading by the time your Javascript is executed on the client side.

If Javascript is your only option, your best best is to make your script the first .js file included in the <head> of your document.

Instead of Javascript, I recommend setting up your redirect logic in your Apache or nginx server configuration.

Get list of data-* attributes using javascript / jQuery

One way of finding all data attributes is using element.attributes. Using .attributes, you can loop through all of the element attributes, filtering out the items which include the string "data-".

let element = document.getElementById("element");

function getDataAttributes(element){
    let elementAttributes = {},
        i = 0;

    while(i < element.attributes.length){
        if(element.attributes[i].name.includes("data-")){
            elementAttributes[element.attributes[i].name] = element.attributes[i].value
        }
        i++;
    }

    return elementAttributes;

}

How can I make setInterval also work when a tab is inactive in Chrome?

I was able to call my callback function at minimum of 250ms using audio tag and handling its ontimeupdate event. Its called 3-4 times in a second. Its better than one second lagging setTimeout

Which command in VBA can count the number of characters in a string variable?

Try this:

word = "habit"
findchar = 'b"
replacechar = ""
charactercount = len(word) - len(replace(word,findchar,replacechar))

How To Convert A Number To an ASCII Character?

You can use one of these methods to convert number to an ASCII / Unicode / UTF-16 character:

You can use these methods convert the value of the specified 32-bit signed integer to its Unicode character:

char c = (char)65;
char c = Convert.ToChar(65); 

Also, ASCII.GetString decodes a range of bytes from a byte array into a string:

string s = Encoding.ASCII.GetString(new byte[]{ 65 });

Keep in mind that, ASCIIEncoding does not provide error detection. Any byte greater than hexadecimal 0x7F is decoded as the Unicode question mark ("?").

ERROR 1064 (42000) in MySQL

This was my case: I forgot to add ' before );

End of file.sql with error:

...
('node','ad','0','3879','3879','und','0','-14.30602','-170.696181','0','0','0'),
('node','ad','0','3880','3880','und','0','-14.30602','-170.696181','0','0','0);

End of file.sql without error:

...
('node','ad','0','3879','3879','und','0','-14.30602','-170.696181','0','0','0'),
('node','ad','0','3880','3880','und','0','-14.30602','-170.696181','0','0','0');

numpy matrix vector multiplication

Simplest solution

Use numpy.dot or a.dot(b). See the documentation here.

>>> a = np.array([[ 5, 1 ,3], 
                  [ 1, 1 ,1], 
                  [ 1, 2 ,1]])
>>> b = np.array([1, 2, 3])
>>> print a.dot(b)
array([16, 6, 8])

This occurs because numpy arrays are not matrices, and the standard operations *, +, -, / work element-wise on arrays. Instead, you could try using numpy.matrix, and * will be treated like matrix multiplication.


Other Solutions

Also know there are other options:

  • As noted below, if using python3.5+ the @ operator works as you'd expect:

    >>> print(a @ b)
    array([16, 6, 8])
    
  • If you want overkill, you can use numpy.einsum. The documentation will give you a flavor for how it works, but honestly, I didn't fully understand how to use it until reading this answer and just playing around with it on my own.

    >>> np.einsum('ji,i->j', a, b)
    array([16, 6, 8])
    
  • As of mid 2016 (numpy 1.10.1), you can try the experimental numpy.matmul, which works like numpy.dot with two major exceptions: no scalar multiplication but it works with stacks of matrices.

    >>> np.matmul(a, b)
    array([16, 6, 8])
    
  • numpy.inner functions the same way as numpy.dot for matrix-vector multiplication but behaves differently for matrix-matrix and tensor multiplication (see Wikipedia regarding the differences between the inner product and dot product in general or see this SO answer regarding numpy's implementations).

    >>> np.inner(a, b)
    array([16, 6, 8])
    
    # Beware using for matrix-matrix multiplication though!
    >>> b = a.T
    >>> np.dot(a, b)
    array([[35,  9, 10],
           [ 9,  3,  4],
           [10,  4,  6]])
    >>> np.inner(a, b) 
    array([[29, 12, 19],
           [ 7,  4,  5],
           [ 8,  5,  6]])
    

Rarer options for edge cases

  • If you have tensors (arrays of dimension greater than or equal to one), you can use numpy.tensordot with the optional argument axes=1:

    >>> np.tensordot(a, b, axes=1)
    array([16,  6,  8])
    
  • Don't use numpy.vdot if you have a matrix of complex numbers, as the matrix will be flattened to a 1D array, then it will try to find the complex conjugate dot product between your flattened matrix and vector (which will fail due to a size mismatch n*m vs n).

How to convert DataTable to class Object?

Amit, I have used one way to achieve this with less coding and more efficient way.

but it uses Linq.

I posted it here because maybe the answer helps other SO.

Below DAL code converts datatable object to List of YourViewModel and it's easy to understand.

public static class DAL
{
        public static string connectionString = ConfigurationManager.ConnectionStrings["YourWebConfigConnection"].ConnectionString;

        // function that creates a list of an object from the given data table
        public static List<T> CreateListFromTable<T>(DataTable tbl) where T : new()
        {
            // define return list
            List<T> lst = new List<T>();

            // go through each row
            foreach (DataRow r in tbl.Rows)
            {
                // add to the list
                lst.Add(CreateItemFromRow<T>(r));
            }

            // return the list
            return lst;
        }

        // function that creates an object from the given data row
        public static T CreateItemFromRow<T>(DataRow row) where T : new()
        {
            // create a new object
            T item = new T();

            // set the item
            SetItemFromRow(item, row);

            // return 
            return item;
        }

        public static void SetItemFromRow<T>(T item, DataRow row) where T : new()
        {
            // go through each column
            foreach (DataColumn c in row.Table.Columns)
            {
                // find the property for the column
                PropertyInfo p = item.GetType().GetProperty(c.ColumnName);

                // if exists, set the value
                if (p != null && row[c] != DBNull.Value)
                {
                    p.SetValue(item, row[c], null);
                }
            }
        }

        //call stored procedure to get data.
        public static DataSet GetRecordWithExtendedTimeOut(string SPName, params SqlParameter[] SqlPrms)
        {
            DataSet ds = new DataSet();
            SqlCommand cmd = new SqlCommand();
            SqlDataAdapter da = new SqlDataAdapter();
            SqlConnection con = new SqlConnection(connectionString);

            try
            {
                cmd = new SqlCommand(SPName, con);
                cmd.Parameters.AddRange(SqlPrms);
                cmd.CommandTimeout = 240;
                cmd.CommandType = CommandType.StoredProcedure;
                da.SelectCommand = cmd;
                da.Fill(ds);
            }
            catch (Exception ex)
            {
               return ex;
            }

            return ds;
        }
}

Now, The way to pass and call method is below.

    DataSet ds = DAL.GetRecordWithExtendedTimeOut("ProcedureName");

    List<YourViewModel> model = new List<YourViewModel>();

    if (ds != null)
    {
        //Pass datatable from dataset to our DAL Method.
        model = DAL.CreateListFromTable<YourViewModel>(ds.Tables[0]);                
    }      

Till the date, for many of my applications, I found this as the best structure to get data.

How to return multiple values?

You can only return one value, but it can be an object that has multiple fields - ie a "value object". Eg

public class MyResult {
    int returnCode;
    String errorMessage;
    // etc
}

public MyResult someMethod() {
    // impl here
}

Java - Create a new String instance with specified length and filled with specific character. Best solution?

public static String fillString(int count,char c) {
    StringBuilder sb = new StringBuilder( count );
    for( int i=0; i<count; i++ ) {
        sb.append( c ); 
    }
    return sb.toString();
}

What is wrong?

What is "with (nolock)" in SQL Server?

The text book example for legitimate usage of the nolock hint is report sampling against a high update OLTP database.

To take a topical example. If a large US high street bank wanted to run an hourly report looking for the first signs of a city level run on the bank, a nolock query could scan transaction tables summing cash deposits and cash withdrawals per city. For such a report the tiny percentage of error caused by rolled back update transactions would not reduce the value of the report.

Pythonic way to check if a list is sorted or not

A solution using assignment expressions (added in Python 3.8):

def is_sorted(seq):
    seq_iter = iter(seq)
    cur = next(seq_iter, None)
    return all((prev := cur) <= (cur := nxt) for nxt in seq_iter)

z = list(range(10))
print(z)
print(is_sorted(z))

import random
random.shuffle(z)
print(z)
print(is_sorted(z))

z = []
print(z)
print(is_sorted(z))

Gives:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
True
[1, 7, 5, 9, 4, 0, 8, 3, 2, 6]
False
[]
True

Function pointer to member function

Building on @IllidanS4 's answer, I have created a template class that allows virtually any member function with predefined arguments and class instance to be passed by reference for later calling.



template<class RET, class... RArgs> class Callback_t {
public:
    virtual RET call(RArgs&&... rargs) = 0;
    //virtual RET call() = 0;
};

template<class T, class RET, class... RArgs> class CallbackCalltimeArgs : public Callback_t<RET, RArgs...> {
public:
    T * owner;
    RET(T::*x)(RArgs...);
    RET call(RArgs&&... rargs) {
        return (*owner.*(x))(std::forward<RArgs>(rargs)...);
    };
    CallbackCalltimeArgs(T* t, RET(T::*x)(RArgs...)) : owner(t), x(x) {}
};

template<class T, class RET, class... Args> class CallbackCreattimeArgs : public Callback_t<RET> {
public:
    T* owner;
    RET(T::*x)(Args...);
    RET call() {
        return (*owner.*(x))(std::get<Args&&>(args)...);
    };
    std::tuple<Args&&...> args;
    CallbackCreattimeArgs(T* t, RET(T::*x)(Args...), Args&&... args) : owner(t), x(x),
        args(std::tuple<Args&&...>(std::forward<Args>(args)...)) {}
};

Test / example:

class container {
public:
    static void printFrom(container* c) { c->print(); };
    container(int data) : data(data) {};
    ~container() {};
    void print() { printf("%d\n", data); };
    void printTo(FILE* f) { fprintf(f, "%d\n", data); };
    void printWith(int arg) { printf("%d:%d\n", data, arg); };
private:
    int data;
};

int main() {
    container c1(1), c2(20);
    CallbackCreattimeArgs<container, void> f1(&c1, &container::print);
    Callback_t<void>* fp1 = &f1;
    fp1->call();//1
    CallbackCreattimeArgs<container, void, FILE*> f2(&c2, &container::printTo, stdout);
    Callback_t<void>* fp2 = &f2;
    fp2->call();//20
    CallbackCalltimeArgs<container, void, int> f3(&c2, &container::printWith);
    Callback_t<void, int>* fp3 = &f3;
    fp3->call(15);//20:15
}

Obviously, this will only work if the given arguments and owner class are still valid. As far as readability... please forgive me.

Edit: removed unnecessary malloc by making the tuple normal storage. Added inherited type for the reference. Added option to provide all arguments at calltime instead. Now working on having both....

Edit 2: As promised, both. Only restriction (that I see) is that the predefined arguments must come before the runtime supplied arguments in the callback function. Thanks to @Chipster for some help with gcc compliance. This works on gcc on ubuntu and visual studio on windows.

#ifdef _WIN32
#define wintypename typename
#else
#define wintypename
#endif

template<class RET, class... RArgs> class Callback_t {
public:
    virtual RET call(RArgs... rargs) = 0;
    virtual ~Callback_t() = default;
};

template<class RET, class... RArgs> class CallbackFactory {
private:
    template<class T, class... CArgs> class Callback : public Callback_t<RET, RArgs...> {
    private:
        T * owner;
        RET(T::*x)(CArgs..., RArgs...);
        std::tuple<CArgs...> cargs;
        RET call(RArgs... rargs) {
            return (*owner.*(x))(std::get<CArgs>(cargs)..., rargs...);
        };
    public:
        Callback(T* t, RET(T::*x)(CArgs..., RArgs...), CArgs... pda);
        ~Callback() {};
    };
public:
    template<class U, class... CArgs> static Callback_t<RET, RArgs...>* make(U* owner, CArgs... cargs, RET(U::*func)(CArgs..., RArgs...));
};
template<class RET2, class... RArgs2> template<class T2, class... CArgs2> CallbackFactory<RET2, RArgs2...>::Callback<T2, CArgs2...>::Callback(T2* t, RET2(T2::*x)(CArgs2..., RArgs2...), CArgs2... pda) : x(x), owner(t), cargs(std::forward<CArgs2>(pda)...) {}
template<class RET, class... RArgs> template<class U, class... CArgs> Callback_t<RET, RArgs...>* CallbackFactory<RET, RArgs...>::make(U* owner, CArgs... cargs, RET(U::*func)(CArgs..., RArgs...)) {
    return new wintypename CallbackFactory<RET, RArgs...>::Callback<U, CArgs...>(owner, func, std::forward<CArgs>(cargs)...);
}

How to detect string which contains only spaces?

Trim your String value by creating a trim function

var text = "  ";
if($.trim(text.length == 0){
  console.log("Text is empty");
}
else
{
  console.log("Text is not empty");
}

How to do an Integer.parseInt() for a decimal number?

Using BigDecimal to get rounding:

String s1="0.01";
int i1 = new BigDecimal(s1).setScale(0, RoundingMode.HALF_UP).intValueExact();

String s2="0.5";
int i2 = new BigDecimal(s2).setScale(0, RoundingMode.HALF_UP).intValueExact();

double free or corruption (!prev) error in c program

I didn't check all the code but my guess is that the error is in the malloc call. You have to replace

 double *ptr = malloc(sizeof(double*) * TIME);

for

 double *ptr = malloc(sizeof(double) * TIME);

since you want to allocate size for a double (not the size of a pointer to a double).

How to use onClick() or onSelect() on option tag in a JSP page?

Other option, for similar example but with anidated selects, think that you have two select, the name of the first is "ea_pub_dest" and the name of the second is "ea_pub_dest_2", ok, now take the event click of the first and display the second.

<script>

function test()
{
    value = document.getElementById("ea_pub_dest").value;
    if ( valor == "value_1" )
        document.getElementById("ea_pub_dest_nivel").style.display = "block";
}
</script>

Using Spring MVC Test to unit test multipart POST request

Have a look at this example taken from the spring MVC showcase, this is the link to the source code:

@RunWith(SpringJUnit4ClassRunner.class)
public class FileUploadControllerTests extends AbstractContextControllerTests {

    @Test
    public void readString() throws Exception {

        MockMultipartFile file = new MockMultipartFile("file", "orig", null, "bar".getBytes());

        webAppContextSetup(this.wac).build()
            .perform(fileUpload("/fileupload").file(file))
            .andExpect(model().attribute("message", "File 'orig' uploaded successfully"));
    }

}

Where do I configure log4j in a JUnit test class?

You may want to look into to Simple Logging Facade for Java (SLF4J). It is a facade that wraps around Log4j that doesn't require an initial setup call like Log4j. It is also fairly easy to switch out Log4j for Slf4j as the API differences are minimal.

find a minimum value in an array of floats

If you want to use numpy, you must define darr to be a numpy array, not a list:

import numpy as np
darr = np.array([1, 3.14159, 1e100, -2.71828])
print(darr.min())

darr.argmin() will give you the index corresponding to the minimum.

The reason you were getting an error is because argmin is a method understood by numpy arrays, but not by Python lists.

Map enum in JPA with fixed values?

For versions earlier than JPA 2.1, JPA provides only two ways to deal with enums, by their name or by their ordinal. And the standard JPA doesn't support custom types. So:

  • If you want to do custom type conversions, you'll have to use a provider extension (with Hibernate UserType, EclipseLink Converter, etc). (the second solution). ~or~
  • You'll have to use the @PrePersist and @PostLoad trick (the first solution). ~or~
  • Annotate getter and setter taking and returning the int value ~or~
  • Use an integer attribute at the entity level and perform a translation in getters and setters.

I'll illustrate the latest option (this is a basic implementation, tweak it as required):

@Entity
@Table(name = "AUTHORITY_")
public class Authority implements Serializable {

    public enum Right {
        READ(100), WRITE(200), EDITOR (300);

        private int value;

        Right(int value) { this.value = value; }    

        public int getValue() { return value; }

        public static Right parse(int id) {
            Right right = null; // Default
            for (Right item : Right.values()) {
                if (item.getValue()==id) {
                    right = item;
                    break;
                }
            }
            return right;
        }

    };

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "AUTHORITY_ID")
    private Long id;

    @Column(name = "RIGHT_ID")
    private int rightId;

    public Right getRight () {
        return Right.parse(this.rightId);
    }

    public void setRight(Right right) {
        this.rightId = right.getValue();
    }

}

Simulate a click on 'a' element using javascript/jquery

Using jQuery: $('#gift-close').trigger('click');

Using JavaScript: document.getElementById('gift-close').click();

how to open *.sdf files?

Try LINQPad, it works for SQL Server, MySQL, SQLite and also SDF (SQL CE 4.0). Best of all it's free!

LINQPad

Steps with version 4.35.1:

  1. click 'Add Connection'

  2. Click Next with 'Build data context automatically' and 'Default(LINQ to SQL)' selected.

  3. Under 'Provider' choose 'SQL CE 4.0'.

  4. Under 'Database' with 'Attach database file' selected, choose 'Browse' to select your .sdf file.

  5. Click 'OK'.

  6. Voila! It should show the tables in .sdf and be able to query it via right clicking the table or writing LINQ code in your favorite .NET language or even SQL. How cool is that?

Presenting a UIAlertController properly on an iPad using iOS 8

For me I just needed to add the following:

if let popoverController = alertController.popoverPresentationController {
    popoverController.barButtonItem = navigationItem.rightBarButtonItem
}

MS-access reports - The search key was not found in any record - on save

I know this is a very old post but as I was searching for additional solutions to this same error while running my command (I'd previously encountered the spaces in the Excel wb headers and remedied it with VBA each time the file is updated so I knew it wasn't that). I considered the fact that the xlsm file and DB were on separate network drives but didn't want to explore moving one unless it was my last resort.

I attempted to run the save import manually and there it was right in front of my face. The folder containing the xlsm file had been renamed....I changed the name back to match my saved import and....smh, it was that all along.

Remove empty space before cells in UITableView

I can't say for sure but it looks like you've got an extra UIView stuck between where the Prototype Cells begin and the top of the UITableView. My image looks exactly like yours if you remove the text/lines I added in.

enter image description here

ORA-00054: resource busy and acquire with NOWAIT specified

When you killed the session, the session hangs around for a while in "KILLED" status while Oracle cleans up after it.

If you absolutely must, you can kill the OS process as well (look up v$process.spid), which would release any locks it was holding on to.

See this for more detailed info.

Spring JDBC Template for calling Stored Procedures

There are a number of ways to call stored procedures in Spring.

If you use CallableStatementCreator to declare parameters, you will be using Java's standard interface of CallableStatement, i.e register out parameters and set them separately. Using SqlParameter abstraction will make your code cleaner.

I recommend you looking at SimpleJdbcCall. It may be used like this:

SimpleJdbcCall jdbcCall = new SimpleJdbcCall(jdbcTemplate)
    .withSchemaName(schema)
    .withCatalogName(package)
    .withProcedureName(procedure)();
...
jdbcCall.addDeclaredParameter(new SqlParameter(paramName, OracleTypes.NUMBER));
...
jdbcCall.execute(callParams);

For simple procedures you may use jdbcTemplate's update method:

jdbcTemplate.update("call SOME_PROC (?, ?)", param1, param2);

Query an object array using linq

Add:

using System.Linq;

to the top of your file.

And then:

Car[] carList = ...
var carMake = 
    from item in carList
    where item.Model == "bmw" 
    select item.Make;

or if you prefer the fluent syntax:

var carMake = carList
    .Where(item => item.Model == "bmw")
    .Select(item => item.Make);

Things to pay attention to:

  • The usage of item.Make in the select clause instead if s.Make as in your code.
  • You have a whitespace between item and .Model in your where clause

SQL Server tables: what is the difference between @, # and ##?

if you need a unique global temp table, create your own with a Uniqueidentifier Prefix/Suffix and drop post execution if an if object_id(.... The only drawback is using Dynamic sql and need to drop explicitly.

SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax — PHP — PDO

I've got this exact error, but in my case I was binding values for the LIMIT clause without specifying the type. I'm just dropping this here in case somebody gets this error for the same reason. Without specifying the type LIMIT :limit OFFSET :offset; resulted in LIMIT '10' OFFSET '1'; instead of LIMIT 10 OFFSET 1;. What helps to correct that is the following:

$stmt->bindParam(':limit', intval($limit, 10), \PDO::PARAM_INT);
$stmt->bindParam(':offset', intval($offset, 10), \PDO::PARAM_INT);

window.close() doesn't work - Scripts may close only the windows that were opened by it

The below code worked for me :)

window.open('your current page URL', '_self', '');
window.close();

How to use SQL Select statement with IF EXISTS sub query?

Use CASE:

SELECT 
  TABEL1.Id, 
  CASE WHEN EXISTS (SELECT Id FROM TABLE2 WHERE TABLE2.ID = TABLE1.ID)
       THEN 'TRUE' 
       ELSE 'FALSE'
  END AS NewFiled  
FROM TABLE1

If TABLE2.ID is Unique or a Primary Key, you could also use this:

SELECT 
  TABEL1.Id, 
  CASE WHEN TABLE2.ID IS NOT NULL
       THEN 'TRUE' 
       ELSE 'FALSE'
  END AS NewFiled  
FROM TABLE1
  LEFT JOIN Table2
    ON TABLE2.ID = TABLE1.ID

Vue.js getting an element within a component

In Vue2 be aware that you can access this.$refs.uniqueName only after mounting the component.

How to insert multiple rows from array using CodeIgniter framework?

You could always use mysql's LOAD DATA:

LOAD DATA LOCAL INFILE '/full/path/to/file/foo.csv' INTO TABLE `footable` FIELDS TERMINATED BY ',' LINES TERMINATED BY '\r\n' 

to do bulk inserts rather than using a bunch of INSERT statements.

How to put attributes via XElement

Add XAttribute in the constructor of the XElement, like

new XElement("Conn", new XAttribute("Server", comboBox1.Text));

You can also add multiple attributes or elements via the constructor

new XElement("Conn", new XAttribute("Server", comboBox1.Text), new XAttribute("Database", combobox2.Text));

or you can use the Add-Method of the XElement to add attributes

XElement element = new XElement("Conn");
XAttribute attribute = new XAttribute("Server", comboBox1.Text);
element.Add(attribute);

Fastest way to compute entropy in Python

Following the suggestion from unutbu I create a pure python implementation.

def entropy2(labels):
 """ Computes entropy of label distribution. """
    n_labels = len(labels)

    if n_labels <= 1:
        return 0

    counts = np.bincount(labels)
    probs = counts / n_labels
    n_classes = np.count_nonzero(probs)

    if n_classes <= 1:
        return 0

    ent = 0.

    # Compute standard entropy.
    for i in probs:
        ent -= i * log(i, base=n_classes)

    return ent

The point I was missing was that labels is a large array, however probs is 3 or 4 elements long. Using pure python my application now is twice as fast.

Date formatting in WPF datagrid

This is a very old question, but I found a new solution, so I wrote about it.

First of all, is this way of solution possible while using AutoGenerateColumns?

Yes, that can be done with AttachedProperty as follows.

<DataGrid AutoGenerateColumns="True" 
   local:DataGridOperation.DateTimeFormatAutoGenerate="yy-MM-dd"
   ItemsSource="{Binding}" />

AttachedProperty

There are two AttachedProperty defined that allow you to specify two formats. DateTimeFormatAutoGenerate for DateTime and TimeSpanFormatAutoGenerate for TimeSpan.

class DataGridOperation
{
    public static string GetDateTimeFormatAutoGenerate(DependencyObject obj) => (string)obj.GetValue(DateTimeFormatAutoGenerateProperty);
    public static void SetDateTimeFormatAutoGenerate(DependencyObject obj, string value) => obj.SetValue(DateTimeFormatAutoGenerateProperty, value);
    public static readonly DependencyProperty DateTimeFormatAutoGenerateProperty =
        DependencyProperty.RegisterAttached("DateTimeFormatAutoGenerate", typeof(string), typeof(DataGridOperation),
            new PropertyMetadata(null, (d, e) => AddEventHandlerOnGenerating<DateTime>(d, e)));

    public static string GetTimeSpanFormatAutoGenerate(DependencyObject obj) => (string)obj.GetValue(TimeSpanFormatAutoGenerateProperty);
    public static void SetTimeSpanFormatAutoGenerate(DependencyObject obj, string value) => obj.SetValue(TimeSpanFormatAutoGenerateProperty, value);
    public static readonly DependencyProperty TimeSpanFormatAutoGenerateProperty =
        DependencyProperty.RegisterAttached("TimeSpanFormatAutoGenerate", typeof(string), typeof(DataGridOperation),
            new PropertyMetadata(null, (d, e) => AddEventHandlerOnGenerating<TimeSpan>(d, e)));

    private static void AddEventHandlerOnGenerating<T>(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (!(d is DataGrid dGrid))
            return;

        if ((e.NewValue is string format))
            dGrid.AutoGeneratingColumn += (o, e) => AddFormat_OnGenerating<T>(e, format);
    }

    private static void AddFormat_OnGenerating<T>(DataGridAutoGeneratingColumnEventArgs e, string format)
    {
        if (e.PropertyType == typeof(T))
            (e.Column as DataGridTextColumn).Binding.StringFormat = format;
    }
}

How to use

View

<Window
   x:Class="DataGridAutogenerateCustom.MainWindow"
   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   xmlns:local="clr-namespace:DataGridAutogenerateCustom"
   Width="400" Height="250">
   <Window.DataContext>
      <local:MainWindowViewModel />
   </Window.DataContext>
   <StackPanel>
      <TextBlock Text="DEFAULT FORMAT" />
      <DataGrid ItemsSource="{Binding Dates}" />

      <TextBlock Margin="0,30,0,0" Text="CUSTOM FORMAT" />
      <DataGrid
         local:DataGridOperation.DateTimeFormatAutoGenerate="yy-MM-dd"
         local:DataGridOperation.TimeSpanFormatAutoGenerate="dd\-hh\-mm\-ss"
         ItemsSource="{Binding Dates}" />
   </StackPanel>
</Window>

ViewModel

public class MainWindowViewModel
{
    public DatePairs[] Dates { get; } = new DatePairs[]
    {
        new (){StartDate= new (2011,1,1), EndDate= new (2011,2,1) },
        new (){StartDate= new (2020,1,1), EndDate= new (2021,1,1) },
    };
}

public class DatePairs
{
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
    public TimeSpan Span => EndDate - StartDate;
}

demo_wpf_datagrid

How to query DATETIME field using only date in Microsoft SQL Server?

select *
  from invoice
 where TRUNC(created_date) <=TRUNC(to_date('04-MAR-18 15:00:00','dd-mon-yy hh24:mi:ss'));

Selecting a row of pandas series/dataframe by integer index

The primary purpose of the DataFrame indexing operator, [] is to select columns.

When the indexing operator is passed a string or integer, it attempts to find a column with that particular name and return it as a Series.

So, in the question above: df[2] searches for a column name matching the integer value 2. This column does not exist and a KeyError is raised.


The DataFrame indexing operator completely changes behavior to select rows when slice notation is used

Strangely, when given a slice, the DataFrame indexing operator selects rows and can do so by integer location or by index label.

df[2:3]

This will slice beginning from the row with integer location 2 up to 3, exclusive of the last element. So, just a single row. The following selects rows beginning at integer location 6 up to but not including 20 by every third row.

df[6:20:3]

You can also use slices consisting of string labels if your DataFrame index has strings in it. For more details, see this solution on .iloc vs .loc.

I almost never use this slice notation with the indexing operator as its not explicit and hardly ever used. When slicing by rows, stick with .loc/.iloc.

What is the 'new' keyword in JavaScript?

There are already some very great answers but I'm posting a new one to emphasize my observation on case III below about what happens when you have an explicit return statement in a function which you are newing up. Have a look at below cases:

Case I:

var Foo = function(){
  this.A = 1; 
  this.B = 2;
};
console.log(Foo()); //prints undefined
console.log(window.A); //prints 1

Above is a plain case of calling the anonymous function pointed by Foo. When you call this function it returns undefined. Since there is no explicit return statement so JavaScript interpreter forcefully inserts a return undefined; statement in the end of the function. Here window is the invocation object (contextual this) which gets new A and B properties.

Case II:

var Foo = function(){
  this.A = 1;
  this.B = 2;
};
var bar = new Foo();
console.log(bar()); //illegal isn't pointing to a function but an object
console.log(bar.A); //prints 1

Here JavaScript interpreter seeing the new keyword creates a new object which acts as the invocation object (contextual this) of anonymous function pointed by Foo. In this case A and B become properties on the newly created object (in place of window object). Since you don't have any explicit return statement so JavaScript interpreter forcefully inserts a return statement to return the new object created due to usage of new keyword.

Case III:

var Foo = function(){
  this.A = 1;
  this.B = 2;
  return {C:20,D:30}; 
};
var bar = new Foo();
console.log(bar.C);//prints 20
console.log(bar.A); //prints undefined. bar is not pointing to the object which got created due to new keyword.

Here again JavaScript interpreter seeing the new keyword creates a new object which acts as the invocation object (contextual this) of anonymous function pointed by Foo. Again, A and B become properties on the newly created object. But this time you have an explicit return statement so JavaScript interpreter will not do anything of its own.

The thing to note in case III is that the object being created due to new keyword got lost from your radar. bar is actually pointing to a completely different object which is not the one which JavaScript interpreter created due to new keyword.

Quoting David Flanagan from JavaScripit: The Definitive Guide (6th Edition),Ch. 4, Page # 62:

When an object creation expression is evaluated, JavaScript first creates a new empty object, just like the one created by the object initializer {}. Next, it invokes the specified function with the specified arguments, passing the new object as the value of the this keyword. The function can then use this to initialize the properties of the newly created object. Functions written for use as constructors do not return a value, and the value of the object creation expression is the newly created and initialized object. If a constructor does return an object value, that value becomes the value of the object creation expression and the newly created object is discarded.

---Additional Info---

The functions used in code snippet of above cases have special names in JS world as below:

Case I and II - Constructor function

Case III - Factory function. Factory functions shouldn't be used with new keyword which I've done to explain the concept in current thread.

You can read about difference between them in this thread.

angular-cli server - how to proxy API requests to another server?

This was close to working for me. Also had to add:

"changeOrigin": true,
"pathRewrite": {"^/proxy" : ""}

Full proxy.conf.json shown below:

{
    "/proxy/*": {
        "target": "https://url.com",
        "secure": false,
        "changeOrigin": true,
        "logLevel": "debug",
        "pathRewrite": {
            "^/proxy": ""
        }
    }
}

Get Category name from Post ID

Use get_the_category() function.

$post_categories = wp_get_post_categories( 4 );
$categories = get_the_category($post_categories[0]);
var_dump($categories);

Detect Windows version in .net

This is a relatively old question but I've recently had to solve this problem and didn't see my solution posted anywhere.

The easiest (and simplest way in my opinion) is to just use a pinvoke call to RtlGetVersion

[DllImport("ntdll.dll", SetLastError = true)]
internal static extern uint RtlGetVersion(out Structures.OsVersionInfo versionInformation); // return type should be the NtStatus enum

[StructLayout(LayoutKind.Sequential)]
internal struct OsVersionInfo
{
    private readonly uint OsVersionInfoSize;

    internal readonly uint MajorVersion;
    internal readonly uint MinorVersion;

    private readonly uint BuildNumber;

    private readonly uint PlatformId;

    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
    private readonly string CSDVersion;
}

Where Major and Minor version numbers in this struct correspond to the values in the table of the accepted answer.

This returns the correct Windows version number unlike the deprecated GetVersion & GetVersionEx functions from kernel32

How to run Gulp tasks sequentially one after the other

Try this hack :-) Gulp v3.x Hack for Async bug

I tried all of the "official" ways in the Readme, they didn't work for me but this did. You can also upgrade to gulp 4.x but I highly recommend you don't, it breaks so much stuff. You could use a real js promise, but hey, this is quick, dirty, simple :-) Essentially you use:

var wait = 0; // flag to signal thread that task is done
if(wait == 0) setTimeout(... // sleep and let nodejs schedule other threads

Check out the post!

How to add a new project to Github using VS Code

I think I ran into the similar problem. If you started a local git repository but have not set up a remote git project and want to push your local project to to git project.

1) create a remote git project and note the URL of project

2) open/edit your local git project

3) in the VS terminal type: git push --set-upstream [URL of project]

Import a file from a subdirectory?

Try import .lib.BoxTime. For more information read about relative import in PEP 328.

Explaining the 'find -mtime' command

To find all files modified in the last 24 hours use the one below. The -1 here means changed 1 day or less ago.

find . -mtime -1 -ls

what is the basic difference between stack and queue?

STACK:

  1. Stack is defined as a list of element in which we can insert or delete elements only at the top of the stack.
  2. The behaviour of a stack is like a Last-In First-Out(LIFO) system.
  3. Stack is used to pass parameters between function. On a call to a function, the parameters and local variables are stored on a stack.
  4. High-level programming languages such as Pascal, c, etc. that provide support for recursion use the stack for bookkeeping. Remember in each recursive call, there is a need to save the current value of parameters, local variables, and the return address (the address to which the control has to return after the call).

QUEUE:

  1. Queue is a collection of the same type of element. It is a linear list in which insertions can take place at one end of the list,called rear of the list, and deletions can take place only at other end, called the front of the list
  2. The behaviour of a queue is like a First-In-First-Out (FIFO) system.

Difference between numeric, float and decimal in SQL Server

The case for Decimal

What it the underlying need?

It arises from the fact that, ultimately, computers represent, internally, numbers in binary format. That leads, inevitably, to rounding errors.

Consider this:

0.1 (decimal, or "base 10") = .00011001100110011... (binary, or "base 2")

The above ellipsis [...] means 'infinite'. If you look at it carefully, there is an infinite repeating pattern (='0011')

So, at some point the computer has to round that value. This leads to accumulation errors deriving from the repeated use of numbers that are inexactly stored.

Say that you want to store financial amounts (which are numbers that may have a fractional part). First of all, you cannot use integers obviously (integers don't have a fractional part). From a purely mathematical point of view, the natural tendency would be to use a float. But, in a computer, floats have the part of a number that is located after a decimal point - the "mantissa" - limited. That leads to rounding errors.

To overcome this, computers offer specific datatypes that limit the binary rounding error in computers for decimal numbers. These are the data type that should absolutely be used to represent financial amounts. These data types typically go by the name of Decimal. That's the case in C#, for example. Or, DECIMAL in most databases.

How do I break out of a loop in Perl?

For Perl one-liners with implicit loops (using -n or -p command line options), use last or last LINE to break out of the loop that iterates over input records. For example, these simple examples all print the first 2 lines of the input:

echo 1 2 3 4 | xargs -n1 | perl -ne 'last if $. == 3; print;'
echo 1 2 3 4 | xargs -n1 | perl -ne 'last LINE if $. == 3; print;'
echo 1 2 3 4 | xargs -n1 | perl -pe 'last if $. == 3;'
echo 1 2 3 4 | xargs -n1 | perl -pe 'last LINE if $. == 3;'

All print:

1
2

The perl one-liners use these command line flags:
-e : tells Perl to look for code in-line, instead of in a file.
-n : loop over the input one line at a time, assigning it to $_ by default.
-p : same as -n, also add print after each loop iteration over the input.

SEE ALSO:

last docs
last, next, redo, continue - an illustrated example
perlrun: command line switches docs


More examples of last in Perl one-liners:

Break one liner command line script after first match
Print the first N lines of a huge file

How to mark a build unstable in Jenkins when running shell scripts

One easy way to set a build as unstable, is in your "execute shell" block, run exit 13

How to log out user from web site using BASIC authentication?

This isn't directly possible with Basic-Authentication.

There's no mechanism in the HTTP specification for the server to tell the browser to stop sending the credentials that the user already presented.

There are "hacks" (see other answers) typically involving using XMLHttpRequest to send an HTTP request with incorrect credentials to overwrite the ones originally supplied.

What is Teredo Tunneling Pseudo-Interface?

Is to do with IPv6

All the gory details here: http://www.microsoft.com/technet/network/ipv6/teredo.mspx

Some people have had issues with it, and disabled it, but as a general rule, if it aint broke...

Why is the jquery script not working?

<script type="text/javascript" >
    do your codes here  it will work..
    type="text/javascript" is important for jquery 
<script>

Expected response code 220 but got code "", with message "" in Laravel

if you are using Swift Mailer: please ensure that your $transport variable is similar to the below, based on tests i have done, that error results from ssl and port misconfiguration. note: you must include 'ssl' or 'tls' in the transport variable.

EXAMPLE CODE:

// Create the Transport
$transport = (new Swift_SmtpTransport('smtp.gmail.com', 465, 'ssl'))
  ->setUsername([email protected])
  ->setPassword(password)
;

// Create the Mailer using your created Transport
$mailer = new Swift_Mailer($transport);

// Create a message
$message = (new Swift_Message('News Letter Subscription'))
  ->setFrom(['[email protected]' => 'A Name'])
  ->setTo(['[email protected]' => 'A Name'])
  ->setBody('your message body')
  ;

// Send the message
$result = $mailer->send($message);

What is the difference between public, protected, package-private and private in Java?

Private: Limited access to class only

Default (no modifier): Limited access to class and package

Protected: Limited access to class, package and subclasses (both inside and outside package)

Public: Accessible to class, package (all), and subclasses... In short, everywhere.

Creating your own header file in C

header files contain prototypes for functions you define in a .c or .cpp/.cxx file (depending if you're using c or c++). You want to place #ifndef/#defines around your .h code so that if you include the same .h twice in different parts of your programs, the prototypes are only included once.

client.h

#ifndef CLIENT_H
#define CLIENT_H

short socketConnect(char *host,unsigned short port,char *sendbuf,char *recievebuf, long rbufsize);


#endif /** CLIENT_H */

Then you'd implement the .h in a .c file like so:

client.c

#include "client.h"

short socketConnect(char *host,unsigned short port,char *sendbuf,char *recievebuf, long rbufsize) {
 short ret = -1;
 //some implementation here
 return ret;
}

How can I get the file name from request.FILES?

The answer may be outdated, since there is a name property on the UploadedFile class. See: Uploaded Files and Upload Handlers (Django docs). So, if you bind your form with a FileField correctly, the access should be as easy as:

if form.is_valid():
    form.cleaned_data['my_file'].name

PHP - check if variable is undefined

To check is variable is set you need to use isset function.

$lorem = 'potato';

if(isset($lorem)){
    echo 'isset true' . '<br />';
}else{
    echo 'isset false' . '<br />';
}

if(isset($ipsum)){
    echo 'isset true' . '<br />';
}else{
    echo 'isset false' . '<br />';
}

this code will print:

isset true
isset false

read more in https://php.net/manual/en/function.isset.php

Storing and displaying unicode string (??????) using PHP and MySQL

<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">


<?php 
$con = mysql_connect("localhost","root","");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_query('SET character_set_results=utf8');
mysql_query('SET names=utf8');
mysql_query('SET character_set_client=utf8');
mysql_query('SET character_set_connection=utf8');
mysql_query('SET character_set_results=utf8');
mysql_query('SET collation_connection=utf8_general_ci');

mysql_select_db('onlinetest',$con);

$nith = "CREATE TABLE IF NOT EXISTS `TAMIL` (
  `data` varchar(1000) character set utf8 collate utf8_bin default NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1";

if (!mysql_query($nith,$con))
{
  die('Error: ' . mysql_error());
}

$nithi = "INSERT INTO `TAMIL` VALUES ('??????? ???????? ?????????')";

if (!mysql_query($nithi,$con))
{
  die('Error: ' . mysql_error());
}

$result = mysql_query("SET NAMES utf8");//the main trick
$cmd = "select * from TAMIL";
$result = mysql_query($cmd);
while($myrow = mysql_fetch_row($result))
{
    echo ($myrow[0]);
}
?>
</body>
</html>

C# Base64 String to JPEG Image

First, convert the base 64 string to an Image, then use the Image.Save method.

To convert from base 64 string to Image:

 public Image Base64ToImage(string base64String)
 {
    // Convert base 64 string to byte[]
    byte[] imageBytes = Convert.FromBase64String(base64String);
    // Convert byte[] to Image
    using (var ms = new MemoryStream(imageBytes, 0, imageBytes.Length))
    {
        Image image = Image.FromStream(ms, true);
        return image;
    }
 }

To convert from Image to base 64 string:

public string ImageToBase64(Image image,System.Drawing.Imaging.ImageFormat format)
{
  using (MemoryStream ms = new MemoryStream())
  {
    // Convert Image to byte[]
    image.Save(ms, format);
    byte[] imageBytes = ms.ToArray();

    // Convert byte[] to base 64 string
    string base64String = Convert.ToBase64String(imageBytes);
    return base64String;
  }
}

Finally, you can easily to call Image.Save(filePath); to save the image.

Re-ordering columns in pandas dataframe based on column name

Don't forget to add "inplace=True" to Wes' answer or set the result to a new DataFrame.

df.sort_index(axis=1, inplace=True)

.gitignore after commit

Even after you delete the file(s) and then commit, you will still have those files in history. To delete those, consider using BFG Repo-Cleaner. It is an alternative to git-filter-branch.

month name to month number and vice versa in python

Here is a more comprehensive method that can also accept full month names

def month_string_to_number(string):
    m = {
        'jan': 1,
        'feb': 2,
        'mar': 3,
        'apr':4,
         'may':5,
         'jun':6,
         'jul':7,
         'aug':8,
         'sep':9,
         'oct':10,
         'nov':11,
         'dec':12
        }
    s = string.strip()[:3].lower()

    try:
        out = m[s]
        return out
    except:
        raise ValueError('Not a month')

example:

>>> month_string_to_number("October")
10 
>>> month_string_to_number("oct")
10

Python unexpected EOF while parsing

I had this error, because of a missing closing parenthesis on a line.

I started off having an issue with a line saying: invalid syntax (<string>, line ...)? at the end of my script.

I deleted that line, then got the EOF message.