Programs & Examples On #Clock synchronization

Can I apply the required attribute to <select> fields in HTML5?

The <select> element does support the required attribute, as per the spec:

Which browser doesn’t honour this?

(Of course, you have to validate on the server anyway, as you can’t guarantee that users will have JavaScript enabled.)

<script> tag vs <script type = 'text/javascript'> tag

Douglas Crockford says:

type="text/javascript"

This attribute is optional. Since Netscape 2, the default programming language in all browsers has been JavaScript. In XHTML, this attribute is required and unnecessary. In HTML, it is better to leave it out. The browser knows what to do.

In HTML 4.01 and XHTML 1(.1), the type attribute for <script> elements is required.

Animate element transform rotate

//this should allow you to replica an animation effect for any css property, even //properties //that transform animation jQuery plugins do not allow

            function twistMyElem(){
                var ball = $('#form');
                document.getElementById('form').style.zIndex = 1;
                ball.animate({ zIndex : 360},{
                    step: function(now,fx){
                        ball.css("transform","rotateY(" + now + "deg)");
                    },duration:3000
                }, 'linear');
            } 

How to increase icons size on Android Home Screen?

Unless you write your own Homescreen launcher or use an existing one from Goolge Play, there's "no way" to resize icons.

Well, "no way" does not mean its impossible:

  • As said, you can write your own launcher as discussed in Stackoverflow.
  • You can resize elements on the home screen, but these elements are AppWidgets. Since API level 14 they can be resized and user can - in limits - change the size. But that are Widgets not Shortcuts for launching icons.

Property 'value' does not exist on type 'Readonly<{}>'

I suggest to use

for string only state values

export default class Home extends React.Component<{}, { [key: string]: string }> { }

for string key and any type of state values

export default class Home extends React.Component<{}, { [key: string]: any}> { }

for any key / any values

export default class Home extends React.Component<{}, { [key: any]: any}> {}

How to install/start Postman native v4.10.3 on Ubuntu 16.04 LTS 64-bit?

sudo snap install postman

This single command worked for me.

segmentation fault : 11

This declaration:

double F[1000][1000000];

would occupy 8 * 1000 * 1000000 bytes on a typical x86 system. This is about 7.45 GB. Chances are your system is running out of memory when trying to execute your code, which results in a segmentation fault.

Error running android: Gradle project sync failed. Please fix your project and try again

It is a very common issue and the solution is very easy... Just update the SDK in SDK manager(see full instructions below)

  1. Open Android Studio and go to your SDK Manager(File>Settings>SDK Manager)
  2. Check for (-) icon in front of any package and click on it.
  3. Click OK to start updating the SDK.

Thanks for asking that question :)

What does "O(1) access time" mean?

"Big O notation" is a way to express the speed of algorithms. n is the amount of data the algorithm is working with. O(1) means that, no matter how much data, it will execute in constant time. O(n) means that it is proportional to the amount of data.

Troubleshooting "Warning: session_start(): Cannot send session cache limiter - headers already sent"

I had a website transferring from one host to another, it seemed to work fine on the old host but a few pages on the new host threw the error

Warning: session_start(): Cannot send session cache limiter - headers already sent
while I always kept the

 <?php
session_start(); 

at the top of the page no spaces and nothing inserted before

it really bugged me that I stared every page with the session opening, and it worked on some pages and run through a bug on others I picked the pages that had the problems, backed them up, created new blank pages and simply copied and pasted the code as is, saved and uploaded and boom, problem gone!

this is something you guys may need to consider, it may have been the encoding of the page, or something, not sure the exact source of the problem, but here is a fix to look at in case you guys run into a similar problem

cheers!

pypi UserWarning: Unknown distribution option: 'install_requires'

In conclusion:

distutils doesn't support install_requires or entry_points, setuptools does.

change from distutils.core import setup in setup.py to from setuptools import setup or refactor your setup.py to use only distutils features.

I came here because I hadn't realized entry_points was only a setuptools feature.

If you are here wanting to convert setuptools to distutils like me:

  1. remove install_requires from setup.py and just use requirements.txt with pip
  2. change entry_points to scripts (doc) and refactor any modules relying on entry_points to be full scripts with shebangs and an entry point.

Update select2 data without rebuilding the control

Diego's comment on the answer given by SpinyMan is important because the empty() method will remove the select2 instance, so any custom options will no longer be retained. If you want to keep existing select2 options you must save them, destroy the existing select2 instance, and then re-initialize. You can do that like so:

const options = JSON.parse(JSON.stringify(
  $('#inputhidden').data('select2').options.options
));
options.data = data;

$('#inputhidden').empty().select2('destroy').select2(options);

I would recommend to always explicitly pass the select2 options however, because the above only copies over simple options and not any custom callbacks or adapters. Also note that this requires the latest stable release of select2 (4.0.13 at the time of this post).

I wrote generic functions to handle this with a few features:

  • can handle selectors that return multiple instances
  • use the existing select2's instance options (default) or pass in a new set of options
  • keep any already-selected values (default) that are still valid, or clear them entirely
function select2UpdateOptions(
  selector,
  data,
  newOptions = null,
  keepExistingSelected = true
) {
  // loop through all instances of the matching selector and update each instance
  $(selector).each(function() {
    select2InstanceUpdateOptions($(this), data, newOptions, keepExistingSelected);
  });
}

// update an existing select2 instance with new data options
function select2InstanceUpdateOptions(
  instance,
  data,
  newOptions = null,
  keepSelected = true
) {
  // make sure this instance has select2 initialized
  // @link https://select2.org/programmatic-control/methods#checking-if-the-plugin-is-initialized
  if (!instance.hasClass('select2-hidden-accessible')) {
    return;
  }

  // get the currently selected options
  const existingSelected = instance.val();

  // by default use the existing options of the select2 instance unless overridden
  // this will not copy over any callbacks or custom adapters however
  const options = (newOptions)
    ? newOptions
    : JSON.parse(JSON.stringify(instance.data('select2').options.options))
  ;

  // set the new data options that will be used
  options.data = data;
      
  // empty the select and destroy the existing select2 instance
  // then re-initialize the select2 instance with the given options and data
  instance.empty().select2('destroy').select2(options);
      
  // by default keep options that were already selected;
  // any that are now invalid will automatically be cleared
  if (keepSelected) {
    instance.val(existingSelected).trigger('change');
  }
}

Assign pandas dataframe column dtypes

For those coming from Google (etc.) such as myself:

convert_objects has been deprecated since 0.17 - if you use it, you get a warning like this one:

FutureWarning: convert_objects is deprecated.  Use the data-type specific converters 
pd.to_datetime, pd.to_timedelta and pd.to_numeric.

You should do something like the following:

Javascript: Load an Image from url and display

You have to right idea generating the url based off of the input value. The only issue is you are using window.location.href. Setting window.location.href changes the url of the current window. What you probably want to do is change the src attribute of an image.

<html>
<body>
<form>
  <input type="text" value="" id="imagename">
  <input type="button" onclick="var image = document.getElementById('the-image'); image.src='http://webpage.com/images/'+document.getElementById('imagename').value +'.png'" value="GO">
</form>
<img id="the-image">
</body>
</html>

Test if string begins with a string?

The best methods are already given but why not look at a couple of other methods for fun? Warning: these are more expensive methods but do serve in other circumstances.

The expensive regex method and the css attribute selector with starts with ^ operator

Option Explicit

Public Sub test()

    Debug.Print StartWithSubString("ab", "abc,d")

End Sub

Regex:

Public Function StartWithSubString(ByVal substring As String, ByVal testString As String) As Boolean
    'required reference Microsoft VBScript Regular Expressions
    Dim re As VBScript_RegExp_55.RegExp
    Set re = New VBScript_RegExp_55.RegExp

    re.Pattern = "^" & substring

    StartWithSubString = re.test(testString)

End Function

Css attribute selector with starts with operator

Public Function StartWithSubString(ByVal substring As String, ByVal testString As String) As Boolean
    'required reference Microsoft HTML Object Library
    Dim html As MSHTML.HTMLDocument
    Set html = New MSHTML.HTMLDocument

    html.body.innerHTML = "<div test=""" & testString & """></div>"

    StartWithSubString = html.querySelectorAll("[test^=" & substring & "]").Length > 0

End Function

Array of arrays (Python/NumPy)

You'll have problems creating lists without commas. It shouldn't be too hard to transform your data so that it uses commas as separating character.

Once you have commas in there, it's a relatively simple list creation operations:

array1 = [1,2,3]
array2 = [4,5,6]

array3 = [array1, array2]

array4 = [7,8,9]
array5 = [10,11,12]

array3 = [array3, [array4, array5]]

When testing we get:

print(array3)

[[[1, 2, 3], [4, 5, 6]], [[7, 8, 9], [10, 11, 12]]]

And if we test with indexing it works correctly reading the matrix as made up of 2 rows and 2 columns:

array3[0][1]
[4, 5, 6]

array3[1][1]
[10, 11, 12]

Hope that helps.

Grep and Python

You can use python-textops3 :

from textops import *

print('\n'.join(cat(f) | grep(search_term)))

with python-textops3 you can use unix-like commands with pipes

How to watch for array changes?

An interesting collection library is https://github.com/mgesmundo/smart-collection. Allows you to watch arrays and add views to them as well. Not sure about the performance as I am testing it out myself. Will update this post soon.

Ruby: How to turn a hash into HTTP parameters?

If you are in the context of a Faraday request, you can also just pass the params hash as the second argument and faraday takes care of making proper param URL part out of it:

faraday_instance.get(url, params_hsh)

How do I set the timeout for a JAX-WS webservice client?

The properties in the accepted answer did not work for me, possibly because I'm using the JBoss implementation of JAX-WS?

Using a different set of properties (found in the JBoss JAX-WS User Guide) made it work:

//Set timeout until a connection is established
((BindingProvider)port).getRequestContext().put("javax.xml.ws.client.connectionTimeout", "6000");

//Set timeout until the response is received
((BindingProvider) port).getRequestContext().put("javax.xml.ws.client.receiveTimeout", "1000");

How can I get enum possible values in a MySQL database?

A more up to date way of doing it, this worked for me:

function enum_to_array($table, $field) {    
    $query = "SHOW FIELDS FROM `{$table}` LIKE '{$field}'";
    $result = $db->query($sql);
    $row = $result->fetchRow();
    preg_match('#^enum\((.*?)\)$#ism', $row['Type'], $matches);
    $enum = str_getcsv($matches[1], ",", "'");
    return $enum;
}

Ultimately, the enum values when separated from "enum()" is just a CSV string, so parse it as such!

dd: How to calculate optimal blocksize?

I've found my optimal blocksize to be 8 MB (equal to disk cache?) I needed to wipe (some say: wash) the empty space on a disk before creating a compressed image of it. I used:

cd /media/DiskToWash/
dd if=/dev/zero of=zero bs=8M; rm zero

I experimented with values from 4K to 100M.

After letting dd to run for a while I killed it (Ctlr+C) and read the output:

36+0 records in
36+0 records out
301989888 bytes (302 MB) copied, 15.8341 s, 19.1 MB/s

As dd displays the input/output rate (19.1MB/s in this case) it's easy to see if the value you've picked is performing better than the previous one or worse.

My scores:

bs=   I/O rate
---------------
4K    13.5 MB/s
64K   18.3 MB/s
8M    19.1 MB/s <--- winner!
10M   19.0 MB/s
20M   18.6 MB/s
100M  18.6 MB/s   

Note: To check what your disk cache/buffer size is, you can use sudo hdparm -i /dev/sda

How to disable javax.swing.JButton in java?

The code is very long so I can't paste all the code.

There could be any number of reasons why your code doesn't work. Maybe you declared the button variables twice so you aren't actually changing enabling/disabling the button like you think you are. Maybe you are blocking the EDT.

You need to create a SSCCE to post on the forum.

So its up to you to isolate the problem. Start with a simple frame thas two buttons and see if your code works. Once you get that working, then try starting a Thread that simply sleeps for 10 seconds to see if it still works.

Learn how the basice work first before writing a 200 line program.

Learn how to do some basic debugging, we are not mind readers. We can't guess what silly mistake you are doing based on your verbal description of the problem.

uint8_t vs unsigned char

The whole point is to write implementation-independent code. unsigned char is not guaranteed to be an 8-bit type. uint8_t is (if available).

Error:Execution failed for task ':app:transformClassesWithDexForDebug' in android studio

In my case I had 2 projects A and B. And I upgraded to gradle 4.5.

A was dependent on B but both had references of my 3rd party jar

I was getting this error

com.android.tools.r8.errors.CompilationError: Program type already present: com.mnox.webservice.globals.WebServiceLightErrorHashCode

Program type already present: com.mnox.webservice.globals.WebServiceLightErrorHashCode

To fix it

  1. I removed the duplicate jar's
  2. I used api in the B build.gradle file so that it gets referred to in A.

The other root cause can be if you have upgraded to gradle 4.5 and used implementation instead of api in your commons build.gradle

Spring Boot - How to log all requests and responses with exceptions in single place?

You could use javax.servlet.Filter if there wasn't a requirement to log java method that been executed.

But with this requirement you have to access information stored in handlerMapping of DispatcherServlet. That said, you can override DispatcherServlet to accomplish logging of request/response pair.

Below is an example of idea that can be further enhanced and adopted to your needs.

public class LoggableDispatcherServlet extends DispatcherServlet {

    private final Log logger = LogFactory.getLog(getClass());

    @Override
    protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
        if (!(request instanceof ContentCachingRequestWrapper)) {
            request = new ContentCachingRequestWrapper(request);
        }
        if (!(response instanceof ContentCachingResponseWrapper)) {
            response = new ContentCachingResponseWrapper(response);
        }
        HandlerExecutionChain handler = getHandler(request);

        try {
            super.doDispatch(request, response);
        } finally {
            log(request, response, handler);
            updateResponse(response);
        }
    }

    private void log(HttpServletRequest requestToCache, HttpServletResponse responseToCache, HandlerExecutionChain handler) {
        LogMessage log = new LogMessage();
        log.setHttpStatus(responseToCache.getStatus());
        log.setHttpMethod(requestToCache.getMethod());
        log.setPath(requestToCache.getRequestURI());
        log.setClientIp(requestToCache.getRemoteAddr());
        log.setJavaMethod(handler.toString());
        log.setResponse(getResponsePayload(responseToCache));
        logger.info(log);
    }

    private String getResponsePayload(HttpServletResponse response) {
        ContentCachingResponseWrapper wrapper = WebUtils.getNativeResponse(response, ContentCachingResponseWrapper.class);
        if (wrapper != null) {

            byte[] buf = wrapper.getContentAsByteArray();
            if (buf.length > 0) {
                int length = Math.min(buf.length, 5120);
                try {
                    return new String(buf, 0, length, wrapper.getCharacterEncoding());
                }
                catch (UnsupportedEncodingException ex) {
                    // NOOP
                }
            }
        }
        return "[unknown]";
    }

    private void updateResponse(HttpServletResponse response) throws IOException {
        ContentCachingResponseWrapper responseWrapper =
            WebUtils.getNativeResponse(response, ContentCachingResponseWrapper.class);
        responseWrapper.copyBodyToResponse();
    }

}

HandlerExecutionChain - contains the information about request handler.

You then can register this dispatcher as following:

    @Bean
    public ServletRegistrationBean dispatcherRegistration() {
        return new ServletRegistrationBean(dispatcherServlet());
    }

    @Bean(name = DispatcherServletAutoConfiguration.DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
    public DispatcherServlet dispatcherServlet() {
        return new LoggableDispatcherServlet();
    }

And here's the sample of logs:

http http://localhost:8090/settings/test
i.g.m.s.s.LoggableDispatcherServlet      : LogMessage{httpStatus=500, path='/error', httpMethod='GET', clientIp='127.0.0.1', javaMethod='HandlerExecutionChain with handler [public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)] and 3 interceptors', arguments=null, response='{"timestamp":1472475814077,"status":500,"error":"Internal Server Error","exception":"java.lang.RuntimeException","message":"org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.RuntimeException","path":"/settings/test"}'}

http http://localhost:8090/settings/params
i.g.m.s.s.LoggableDispatcherServlet      : LogMessage{httpStatus=200, path='/settings/httpParams', httpMethod='GET', clientIp='127.0.0.1', javaMethod='HandlerExecutionChain with handler [public x.y.z.DTO x.y.z.Controller.params()] and 3 interceptors', arguments=null, response='{}'}

http http://localhost:8090/123
i.g.m.s.s.LoggableDispatcherServlet      : LogMessage{httpStatus=404, path='/error', httpMethod='GET', clientIp='127.0.0.1', javaMethod='HandlerExecutionChain with handler [public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)] and 3 interceptors', arguments=null, response='{"timestamp":1472475840592,"status":404,"error":"Not Found","message":"Not Found","path":"/123"}'}

UPDATE

In case of errors Spring does automatic error handling. Therefore, BasicErrorController#error is shown as request handler. If you want to preserve original request handler, then you can override this behavior at spring-webmvc-4.2.5.RELEASE-sources.jar!/org/springframework/web/servlet/DispatcherServlet.java:971 before #processDispatchResult is called, to cache original handler.

Something like 'contains any' for Java set?

Use retainAll() in the Set interface. This method provides an intersection of elements common in both sets. See the API docs for more information.

Pass a JavaScript function as parameter

Here it's another approach :

function a(first,second)    
{        
return (second)(first);           
}     

a('Hello',function(e){alert(e+ ' world!');}); //=> Hello world     

How to find first element of array matching a boolean condition in JavaScript?

It should be clear by now that JavaScript offers no such solution natively; here are the closest two derivatives, the most useful first:

  1. Array.prototype.some(fn) offers the desired behaviour of stopping when a condition is met, but returns only whether an element is present; it's not hard to apply some trickery, such as the solution offered by Bergi's answer.

  2. Array.prototype.filter(fn)[0] makes for a great one-liner but is the least efficient, because you throw away N - 1 elements just to get what you need.

Traditional search methods in JavaScript are characterized by returning the index of the found element instead of the element itself or -1. This avoids having to choose a return value from the domain of all possible types; an index can only be a number and negative values are invalid.

Both solutions above don't support offset searching either, so I've decided to write this:

(function(ns) {
  ns.search = function(array, callback, offset) {
    var size = array.length;

    offset = offset || 0;
    if (offset >= size || offset <= -size) {
      return -1;
    } else if (offset < 0) {
      offset = size - offset;
    }

    while (offset < size) {
      if (callback(array[offset], offset, array)) {
        return offset;
      }
      ++offset;
    }
    return -1;
  };
}(this));

search([1, 2, NaN, 4], Number.isNaN); // 2
search([1, 2, 3, 4], Number.isNaN); // -1
search([1, NaN, 3, NaN], Number.isNaN, 2); // 3

Ruby: Easiest Way to Filter Hash Keys?

This is a one line to solve the complete original question:

params.select { |k,_| k[/choice/]}.values.join('\t')

But most the solutions above are solving a case where you need to know the keys ahead of time, using slice or simple regexp.

Here is another approach that works for simple and more complex use cases, that is swappable at runtime

data = {}
matcher = ->(key,value) { COMPLEX LOGIC HERE }
data.select(&matcher)

Now not only this allows for more complex logic on matching the keys or the values, but it is also easier to test, and you can swap the matching logic at runtime.

Ex to solve the original issue:

def some_method(hash, matcher) 
  hash.select(&matcher).values.join('\t')
end

params = { :irrelevant => "A String",
           :choice1 => "Oh look, another one",
           :choice2 => "Even more strings",
           :choice3 => "But wait",
           :irrelevant2 => "The last string" }

some_method(params, ->(k,_) { k[/choice/]}) # => "Oh look, another one\\tEven more strings\\tBut wait"
some_method(params, ->(_,v) { v[/string/]}) # => "Even more strings\\tThe last string"

Getting absolute URLs using ASP.NET Core

After RC2 and 1.0 you no longer need to inject an IHttpContextAccessor to you extension class. It is immediately available in the IUrlHelper through the urlhelper.ActionContext.HttpContext.Request. You would then create an extension class following the same idea, but simpler since there will be no injection involved.

public static string AbsoluteAction(
    this IUrlHelper url,
    string actionName, 
    string controllerName, 
    object routeValues = null)
{
    string scheme = url.ActionContext.HttpContext.Request.Scheme;
    return url.Action(actionName, controllerName, routeValues, scheme);
}

Leaving the details on how to build it injecting the accesor in case they are useful to someone. You might also just be interested in the absolute url of the current request, in which case take a look at the end of the answer.


You could modify your extension class to use the IHttpContextAccessor interface to get the HttpContext. Once you have the context, then you can get the HttpRequest instance from HttpContext.Request and use its properties Scheme, Host, Protocol etc as in:

string scheme = HttpContextAccessor.HttpContext.Request.Scheme;

For example, you could require your class to be configured with an HttpContextAccessor:

public static class UrlHelperExtensions
{        
    private static IHttpContextAccessor HttpContextAccessor;
    public static void Configure(IHttpContextAccessor httpContextAccessor)
    {           
        HttpContextAccessor = httpContextAccessor;  
    }

    public static string AbsoluteAction(
        this IUrlHelper url,
        string actionName, 
        string controllerName, 
        object routeValues = null)
    {
        string scheme = HttpContextAccessor.HttpContext.Request.Scheme;
        return url.Action(actionName, controllerName, routeValues, scheme);
    }

    ....
}

Which is something you can do on your Startup class (Startup.cs file):

public void Configure(IApplicationBuilder app)
{
    ...

    var httpContextAccessor = app.ApplicationServices.GetRequiredService<IHttpContextAccessor>();
    UrlHelperExtensions.Configure(httpContextAccessor);

    ...
}

You could probably come up with different ways of getting the IHttpContextAccessor in your extension class, but if you want to keep your methods as extension methods in the end you will need to inject the IHttpContextAccessor into your static class. (Otherwise you will need the IHttpContext as an argument on each call)


Just getting the absoluteUri of the current request

If you just want to get the absolute uri of the current request, you can use the extension methods GetDisplayUrl or GetEncodedUrl from the UriHelper class. (Which is different from the UrLHelper)

GetDisplayUrl. Returns the combined components of the request URL in a fully un-escaped form (except for the QueryString) suitable only for display. This format should not be used in HTTP headers or other HTTP operations.

GetEncodedUrl. Returns the combined components of the request URL in a fully escaped form suitable for use in HTTP headers and other HTTP operations.

In order to use them:

  • Include the namespace Microsoft.AspNet.Http.Extensions.
  • Get the HttpContext instance. It is already available in some classes (like razor views), but in others you might need to inject an IHttpContextAccessor as explained above.
  • Then just use them as in this.Context.Request.GetDisplayUrl()

An alternative to those methods would be manually crafting yourself the absolute uri using the values in the HttpContext.Request object (Similar to what the RequireHttpsAttribute does):

var absoluteUri = string.Concat(
                        request.Scheme,
                        "://",
                        request.Host.ToUriComponent(),
                        request.PathBase.ToUriComponent(),
                        request.Path.ToUriComponent(),
                        request.QueryString.ToUriComponent());

JavaScript .replace only replaces first Match

You need a /g on there, like this:

_x000D_
_x000D_
var textTitle = "this is a test";_x000D_
var result = textTitle.replace(/ /g, '%20');_x000D_
_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_

You can play with it here, the default .replace() behavior is to replace only the first match, the /g modifier (global) tells it to replace all occurrences.

javascript pushing element at the beginning of an array

Use .unshift() to add to the beginning of an array.

TheArray.unshift(TheNewObject);

See MDN for doc on unshift() and here for doc on other array methods.

FYI, just like there's .push() and .pop() for the end of the array, there's .shift() and .unshift() for the beginning of the array.

How to convert JTextField to String and String to JTextField?

how to convert JTextField to string and string to JTextField in java

If you mean how to get and set String from jTextField then you can use following methods:

String str = jTextField.getText() // get string from jtextfield

and

jTextField.setText(str)  // set string to jtextfield
//or
new JTextField(str)     // set string to jtextfield

You should check JavaDoc for JTextField

"Full screen" <iframe>

You can use this piece of code:

  <iframe src="http://example.com" frameborder="0" style="overflow:hidden;overflow-x:hidden;overflow-y:hidden;height:100%;width:100%;position:absolute;top:0%;left:0px;right:0px;bottom:0px" height="100%" width="100%"></iframe>

MongoDB: How to query for records where field is null or not set?

Seems you can just do single line:

{ "sent_at": null }

What is a NoReverseMatch error, and how do I fix it?

It may be that it's not loading the template you expect. I added a new class that inherited from UpdateView - I thought it would automatically pick the template from what I named my class, but it actually loaded it based on the model property on the class, which resulted in another (wrong) template being loaded. Once I explicitly set template_name for the new class, it worked fine.

Build Android Studio app via command line

Adding value to all these answers,

many have asked the command for running App in AVD after build sucessful.

adb install -r {path-to-your-bild-folder}/{yourAppName}.apk

How to make a phone call using intent in Android?

To avoid this - one can use the GUI for entering permissions. Eclipse take care of where to insert the permission tag and more often then not is correct

BACKUP LOG cannot be performed because there is no current database backup

I am not sure whether the database backup file, you trying to restore, is coming from the same environment as you trying to restore it onto.

Remember that destination path of .mdf and .ldf files lives with the backup file itself.

If this is not a case, that means the backup file is coming from a different environment from your current hosting one, make sure that .mdf and .ldf file path is the same (exists) as on your machine, relocate these otherwise. (Mostly a case of restoring db in Docker image)

The way how to do it: In Databases -> Restore database -> [Files] option -> (Check "Relocate all files to folder" - mostly default path is populated on your hosting environment already)

#1227 - Access denied; you need (at least one of) the SUPER privilege(s) for this operation

It means you don't have privileges to create the trigger with root@localhost user..

try removing definer from the trigger command:

CREATE DEFINER = root@localhost FUNCTION fnc_calcWalkedDistance

How to debug external class library projects in visual studio?

NuGet references

Assume the -Project_A (produces project_a.dll) -Project_B (produces project_b.dll) and Project_B references to Project_A by NuGet packages then just copy project_a.dll , project_a.pdb to the folder Project_B/Packages. In effect that should be copied to the /bin.

Now debug Project_A. When code reaches the part where you need to call dll's method or events etc while debugging, press F11 to step into the dll's code.

Writing a VLOOKUP function in vba

How about just using:

result = [VLOOKUP(DATA!AN2, DATA!AA9:AF20, 5, FALSE)]

Note the [ and ].

How do I tell Maven to use the latest version of a dependency?

Who ever is using LATEST, please make sure you have -U otherwise the latest snapshot won't be pulled.

mvn -U dependency:copy -Dartifact=com.foo:my-foo:LATEST
// pull the latest snapshot for my-foo from all repositories

Android WebView, how to handle redirects in app instead of opening a browser

Create a WebViewClient, and override the shouldOverrideUrlLoading method.

webview.setWebViewClient(new WebViewClient() {
    public boolean shouldOverrideUrlLoading(WebView view, String url){
        // do your handling codes here, which url is the requested url
        // probably you need to open that url rather than redirect:
        view.loadUrl(url);
        return false; // then it is not handled by default action
   }
});

Git Cherry-pick vs Merge Workflow

Rebase and Cherry-pick is the only way you can keep clean commit history. Avoid using merge and avoid creating merge conflict. If you are using gerrit set one project to Merge if necessary and one project to cherry-pick mode and try yourself.

Return a string method in C#

You don't have to have a method for that. You could create a property like this instead:

class SalesPerson
{
    string firstName, lastName;
    public string FirstName { get { return firstName; } set { firstName = value; } }
    public string LastName { get { return lastName; } set { lastName = value; } }
    public string FullName { get { return this.FirstName + " " + this.LastName; } }
}

The class could even be shortened to:

class SalesPerson
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string FullName { 
       get { return this.FirstName + " " + this.LastName; } 
    }
}

The property could then be accessed like any other property:

class Program
{
    static void Main(string[] args)
    {
        SalesPerson x = new SalesPerson("John", "Doe");
        Console.WriteLine(x.FullName); // Will print John Doe
    }
}

MySQL: @variable vs. variable. What's the difference?

MySQL has a concept of user-defined variables.

They are loosely typed variables that may be initialized somewhere in a session and keep their value until the session ends.

They are prepended with an @ sign, like this: @var

You can initialize this variable with a SET statement or inside a query:

SET @var = 1

SELECT @var2 := 2

When you develop a stored procedure in MySQL, you can pass the input parameters and declare the local variables:

DELIMITER //

CREATE PROCEDURE prc_test (var INT)
BEGIN
    DECLARE  var2 INT;
    SET var2 = 1;
    SELECT  var2;
END;
//

DELIMITER ;

These variables are not prepended with any prefixes.

The difference between a procedure variable and a session-specific user-defined variable is that a procedure variable is reinitialized to NULL each time the procedure is called, while the session-specific variable is not:

CREATE PROCEDURE prc_test ()
BEGIN
    DECLARE var2 INT DEFAULT 1;
    SET var2 = var2 + 1;
    SET @var2 = @var2 + 1;
    SELECT  var2, @var2;
END;

SET @var2 = 1;

CALL prc_test();

var2  @var2
---   ---
2     2


CALL prc_test();

var2  @var2
---   ---
2     3


CALL prc_test();

var2  @var2
---   ---
2     4

As you can see, var2 (procedure variable) is reinitialized each time the procedure is called, while @var2 (session-specific variable) is not.

(In addition to user-defined variables, MySQL also has some predefined "system variables", which may be "global variables" such as @@global.port or "session variables" such as @@session.sql_mode; these "session variables" are unrelated to session-specific user-defined variables.)

Ascii/Hex convert in bash

For the first part, try

echo Aa | od -t x1

It prints byte-by-byte

$ echo Aa | od -t x1
0000000 41 61 0a
0000003

The 0a is the implicit newline that echo produces.

Use echo -n or printf instead.

$ printf Aa | od -t x1
0000000 41 61
0000002

Postgresql : syntax error at or near "-"

Wrap it in double quotes

alter user "dell-sys" with password 'Pass@133';

Notice that you will have to use the same case you used when you created the user using double quotes. Say you created "Dell-Sys" then you will have to issue exact the same whenever you refer to that user.

I think the best you do is to drop that user and recreate without illegal identifier characters and without double quotes so you can later refer to it in any case you want.

How to check if image exists with given url?

Use the error handler like this:

$('#image_id').error(function() {
  alert('Image does not exist !!');
});

If the image cannot be loaded (for example, because it is not present at the supplied URL), the alert is displayed:

Update:

I think using:

$.ajax({url:'somefile.dat',type:'HEAD',error:do_something});

would be enough to check for a 404.

More Readings:

Update 2:

Your code should be like this:

$(this).error(function() {
  alert('Image does not exist !!');
});

No need for these lines and that won't check if the remote file exists anyway:

var imgcheck = imgsrc.width;    

if (imgcheck==0) {
  alert("You have a zero size image");
} else { 
  //execute the rest of code here 
}

JQuery Validate input file type

One the elements are added, use the rules method to add the rules

//bug fixed thanks to @Sparky
$('input[name^="fileupload"]').each(function () {
    $(this).rules('add', {
        required: true,
        accept: "image/jpeg, image/pjpeg"
    })
})

Demo: Fiddle


Update

var filenumber = 1;
$("#AddFile").click(function () { //User clicks button #AddFile
    var $li = $('<li><input type="file" name="FileUpload' + filenumber + '" id="FileUpload' + filenumber + '" required=""/> <a href="#" class="RemoveFileUpload">Remove</a></li>').prependTo("#FileUploader");

    $('#FileUpload' + filenumber).rules('add', {
        required: true,
        accept: "image/jpeg, image/pjpeg"
    })

    filenumber++;
    return false;
});

Visualizing branch topology in Git

can we make it more complicated?

How about simple git log --all --decorate --oneline --graph (remember A Dog = --All --Decorate --Oneline --Graph)

Android: How to change the ActionBar "Home" Icon to be something other than the app icon?

The ActionBar will use the android:logo attribute of your manifest, if one is provided. That lets you use separate drawable resources for the icon (Launcher) and the logo (ActionBar, among other things).

mongodb: insert if not exists

In general, using update is better in MongoDB as it will just create the document if it doesn't exist yet, though I'm not sure how to work that with your python adapter.

Second, if you only need to know whether or not that document exists, count() which returns only a number will be a better option than find_one which supposedly transfer the whole document from your MongoDB causing unnecessary traffic.

CSS styling in Django forms

This can be done using a custom template filter. Consider rendering your form this way:

<form action="/contact/" method="post">
  {{ form.non_field_errors }}
  <div class="fieldWrapper">
    {{ form.subject.errors }}
    {{ form.subject.label_tag }}
    {{ form.subject }}
    <span class="helptext">{{ form.subject.help_text }}</span>
  </div>
</form>

form.subject is an instance of BoundField which has the as_widget() method.

You can create a custom filter addclass in my_app/templatetags/myfilters.py:

from django import template

register = template.Library()

@register.filter(name='addclass')
def addclass(value, arg):
    return value.as_widget(attrs={'class': arg})

And then apply your filter:

{% load myfilters %}

<form action="/contact/" method="post">
  {{ form.non_field_errors }}
  <div class="fieldWrapper">
    {{ form.subject.errors }}
    {{ form.subject.label_tag }}
    {{ form.subject|addclass:'MyClass' }}
    <span class="helptext">{{ form.subject.help_text }}</span>
  </div>
</form>

form.subjects will then be rendered with the MyClass CSS class.

How to add native library to "java.library.path" with Eclipse launch (instead of overriding it)

The solution offered by Rob Elsner in one of the comments above works perfectly (OSX 10.9, Eclipse Kepler). One has to append their additional paths to that separated by ":".

You could also use ${system_property:java.library.path} – Rob Elsner Nov 22 '10 at 23:01

Access properties file programmatically with Spring?

CREDIT: Programmatic access to properties in Spring without re-reading the properties file

I've found a nice implementation of accessing the properties programmatically in spring without reloading the same properties that spring has already loaded. [Also, It is not required to hardcode the property file location in the source]

With these changes, the code looks cleaner & more maintainable.

The concept is pretty simple. Just extend the spring default property placeholder (PropertyPlaceholderConfigurer) and capture the properties it loads in the local variable

public class SpringPropertiesUtil extends PropertyPlaceholderConfigurer {

    private static Map<String, String> propertiesMap;
    // Default as in PropertyPlaceholderConfigurer
    private int springSystemPropertiesMode = SYSTEM_PROPERTIES_MODE_FALLBACK;

    @Override
    public void setSystemPropertiesMode(int systemPropertiesMode) {
        super.setSystemPropertiesMode(systemPropertiesMode);
        springSystemPropertiesMode = systemPropertiesMode;
    }

    @Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactory, Properties props) throws BeansException {
        super.processProperties(beanFactory, props);

        propertiesMap = new HashMap<String, String>();
        for (Object key : props.keySet()) {
            String keyStr = key.toString();
            String valueStr = resolvePlaceholder(keyStr, props, springSystemPropertiesMode);
            propertiesMap.put(keyStr, valueStr);
        }
    }

    public static String getProperty(String name) {
        return propertiesMap.get(name).toString();
    }

}

Usage Example

SpringPropertiesUtil.getProperty("myProperty")

Spring configuration changes

<bean id="placeholderConfigMM" class="SpringPropertiesUtil">
    <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE"/>
    <property name="locations">
    <list>
        <value>classpath:myproperties.properties</value>
    </list>
    </property>
</bean>

Hope this helps to solve the problems you have

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demoRestController'

To me it happened in DogController that autowired DogService that autowired DogRepository. Dog class used to have field name but I changed it to coolName, but didn't change methods in DogRepository: Dog findDogByName(String name). I change that method to Dog findDogByCoolName(String name) and now it works.

How do I call a specific Java method on a click/submit event of a specific button in JSP?

You can try adding action="#{yourBean.function1}" on each button (changing of course the method function2, function3, or whatever you need). If that does not work, you can try the same with the onclick event.

Anyway, it would be easier to help you if you tell us what kind of buttons are you trying to use, a4j:commandButton or whatever you are using.

Return JSON with error status code MVC

I was running Asp.Net Web Api 5.2.7 and it looks like the JsonResult class has changed to use generics and an asynchronous execute method. I ended up altering Richard Garside's solution:

public class JsonHttpStatusResult<T> : JsonResult<T>
{
    private readonly HttpStatusCode _httpStatus;

    public JsonHttpStatusResult(T content, JsonSerializerSettings serializer, Encoding encoding, ApiController controller, HttpStatusCode httpStatus) 
    : base(content, serializer, encoding, controller)
    {
        _httpStatus = httpStatus;
    }

    public override Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        var returnTask = base.ExecuteAsync(cancellationToken);
        returnTask.Result.StatusCode = HttpStatusCode.BadRequest;
        return returnTask;
    }
}

Following Richard's example, you could then use this class like this:

if(thereWereErrors)
{
    var errorModel = new CustomErrorModel("There was an error");
    return new JsonHttpStatusResult<CustomErrorModel>(errorModel, new JsonSerializerSettings(), new UTF8Encoding(), this, HttpStatusCode.InternalServerError);
}

Unfortunately, you can't use an anonymous type for the content, as you need to pass a concrete type (ex: CustomErrorType) to the JsonHttpStatusResult initializer. If you want to use anonymous types, or you just want to be really slick, you can build on this solution by subclassing ApiController to add an HttpStatusCode param to the Json methods :)

public abstract class MyApiController : ApiController
{
    protected internal virtual JsonHttpStatusResult<T> Json<T>(T content, HttpStatusCode httpStatus, JsonSerializerSettings serializerSettings, Encoding encoding)
    {
        return new JsonHttpStatusResult<T>(content, httpStatus, serializerSettings, encoding, this);
    }

    protected internal JsonHttpStatusResult<T> Json<T>(T content, HttpStatusCode httpStatus, JsonSerializerSettings serializerSettings)
    {
        return Json(content, httpStatus, serializerSettings, new UTF8Encoding());
    }

    protected internal JsonHttpStatusResult<T> Json<T>(T content, HttpStatusCode httpStatus)
    {
        return Json(content, httpStatus, new JsonSerializerSettings());
    }
}

Then you can use it with an anonymous type like this:

if(thereWereErrors)
{
    var errorModel = new { error = "There was an error" };
    return Json(errorModel, HttpStatusCode.InternalServerError);
}

Using npm behind corporate proxy .pac

None of the existing answers explain how to use npm with a PAC file. Some suggest downloading the PAC file, manually inspecting it, and choosing one of the "PROXY ..." strings. But this doesn't work if the PAC file needs to choose from multiple proxies, or if the PAC file contains complex logic to bypass proxies for certain URLs.

Also, some corporate proxies require NTLM authentication. CNTLM can handle authentication, but doesn't support PAC files.

An alternative is to use Alpaca, which executes the PAC file in a JavaScript VM, and performs NTLM authentication with the resulting proxy.

Java Wait for thread to finish

Generally, when you want to wait for a thread to finish, you should call join() on it.

Read environment variables in Node.js

Why not use them in the Users directory in the .bash_profile file, so you don't have to push any files with your variables to production?

What is mod_php?

It means that you have to have PHP installed as a module in Apache, instead of starting it as a CGI script.

.htaccess or .htpasswd equivalent on IIS?

This is the documentation that you want: http://msdn.microsoft.com/en-us/library/aa292114(VS.71).aspx

I guess the answer is, yes, there is an equivalent that will accomplish the same thing, integrated with Windows security.

What does the "@" symbol do in SQL?

Its a parameter the you need to define. to prevent SQL Injection you should pass all your variables in as parameters.

Finding the handle to a WPF window

If you want window handles for ALL of your application's Windows for some reason, you can use the Application.Windows property to get at all the Windows and then use WindowInteropHandler to get at their handles as you have already demonstrated.

MongoDB: Server has startup warnings ''Access control is not enabled for the database''

Mongodb v3.4

You need to do the following to create a secure database:

Make sure the user starting the process has permissions and that the directories exist (/data/db in this case).

1) Start MongoDB without access control.

mongod --port 27017 --dbpath /data/db

2) Connect to the instance.

mongo --port 27017

3) Create the user administrator (in the admin authentication database).

use admin
db.createUser(
  {
    user: "myUserAdmin",
    pwd: "abc123",
    roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
  }
)

4) Re-start the MongoDB instance with access control.

mongod --auth --port 27017 --dbpath /data/db

5) Connect and authenticate as the user administrator.

mongo --port 27017 -u "myUserAdmin" -p "abc123" --authenticationDatabase "admin"

6) Create additional users as needed for your deployment (e.g. in the test authentication database).

use test
db.createUser(
  {
    user: "myTester",
    pwd: "xyz123",
    roles: [ { role: "readWrite", db: "test" },
             { role: "read", db: "reporting" } ]
  }
)

7) Connect and authenticate as myTester.

mongo --port 27017 -u "myTester" -p "xyz123" --authenticationDatabase "test"

I basically just explained the short version of the official docs here: https://docs.mongodb.com/master/tutorial/enable-authentication/

c++ string array initialization

With support for C++11 initializer lists it is very easy:

#include <iostream>
#include <vector>
#include <string>
using namespace std;

using Strings = vector<string>;

void foo( Strings const& strings )
{
    for( string const& s : strings ) { cout << s << endl; }
}

auto main() -> int
{
    foo( Strings{ "hi", "there" } ); 
}

Lacking that (e.g. for Visual C++ 10.0) you can do things like this:

#include <iostream>
#include <vector>
#include <string>
using namespace std;

typedef vector<string> Strings;

void foo( Strings const& strings )
{
    for( auto it = begin( strings );  it != end( strings );  ++it )
    {
        cout << *it << endl;
    }
}

template< class Elem >
vector<Elem>& r( vector<Elem>&& o ) { return o; }

template< class Elem, class Arg >
vector<Elem>& operator<<( vector<Elem>& v, Arg const& a )
{
    v.push_back( a );
    return v;
}

int main()
{
    foo( r( Strings() ) << "hi" << "there" ); 
}

Checking to see if a DateTime variable has had a value assigned

The only way of having a variable which hasn't been assigned a value in C# is for it to be a local variable - in which case at compile-time you can tell that it isn't definitely assigned by trying to read from it :)

I suspect you really want Nullable<DateTime> (or DateTime? with the C# syntactic sugar) - make it null to start with and then assign a normal DateTime value (which will be converted appropriately). Then you can just compare with null (or use the HasValue property) to see whether a "real" value has been set.

How do you copy the contents of an array to a std::vector in C++ without looping?

In addition to the methods presented above, you need to make sure you use either std::Vector.reserve(), std::Vector.resize(), or construct the vector to size, to make sure your vector has enough elements in it to hold your data. if not, you will corrupt memory. This is true of either std::copy() or memcpy().

This is the reason to use vector.push_back(), you can't write past the end of the vector.

Typescript sleep

import { timer } from 'rxjs';

await timer(1000).pipe(take(1)).toPromise();

this works better for me

What are alternatives to ExtJS?

Nothing compares to in terms of community size and presence on StackOverflow. Despite previous controversy, Ext JS now has a GPLv3 open source license. Its learning curve is long, but it can be quite rewarding once learned. Ext JS lacks a Material Design theme, and the team has repeatedly refused to release the source code on GitHub. For mobile, one must use the separate Sencha Touch library.

Have in mind also that,

large JavaScript libraries, such as YUI, have been receiving less attention from the community. Many developers today look at large JavaScript libraries as walled gardens they don’t want to be locked into.

-- Announcement of YUI development being ceased

That said, below are a number of Ext JS alternatives currently available.

Leading client widget libraries

  1. Blueprint is a React-based UI toolkit developed by big data analytics company Palantir in TypeScript, and "optimized for building complex data-dense interfaces for desktop applications". Actively developed on GitHub as of May 2019, with comprehensive documentation. Components range from simple (chips, toast, icons) to complex (tree, data table, tag input with autocomplete, date range picker. No accordion or resizer.

    Blueprint targets modern browsers (Chrome, Firefox, Safari, IE 11, and Microsoft Edge) and is licensed under a modified Apache license.

    Sandbox / demoGitHubDocs

  2. Webix - an advanced, easy to learn, mobile-friendly, responsive and rich free&open source JavaScript UI components library. Webix spun off from DHTMLX Touch (a project with 8 years of development behind it - see below) and went on to become a standalone UI components framework. The GPL3 edition allows commercial use and lets non-GPL applications using Webix keep their license, e.g. MIT, via a license exemption for FLOSS. Webix has 55 UI widgets, including trees, grids, treegrids and charts. Funding comes from a commercial edition with some advanced widgets (Pivot, Scheduler, Kanban, org chart etc.). Webix has an extensive list of free and commercial widgets, and integrates with most popular frameworks (React, Vue, Meteor, etc) and UI components.

    Webix

    Skins look modern, and include a Material Design theme. The Touch theme also looks quite Material Design-ish. See also the Skin Builder.

    Minimal GitHub presence, but includes the library code, and the documentation (which still needs major improvements). Webix suffers from a having a small team and a lack of marketing. However, they have been responsive to user feedback, both on GitHub and on their forum.

    The library was lean (128Kb gzip+minified for all 55 widgets as of ~2015), faster than ExtJS, dojo and others, and the design is pleasant-looking. The current version of Webix (v6, as of Nov 2018) got heavier (400 - 676kB minified but NOT gzipped).

    The demos on Webix.com look and function great. The developer, XB Software, uses Webix in solutions they build for paying customers, so there's likely a good, funded future ahead of it.

    Webix aims for backwards compatibility down to IE8, and as a result carries some technical debt.

    WikipediaGitHubPlayground/sandboxAdmin dashboard demoDemosWidget samples

  3. react-md - MIT-licensed Material Design UI components library for React. Responsive, accessible. Implements components from simple (buttons, cards) to complex (sortable tables, autocomplete, tags input, calendars). One lead author, ~1900 GitHub stars.

  4. - jQuery-based UI toolkit with 40+ basic open-source widgets, plus commercial professional widgets (grids, trees, charts etc.). Responsive&mobile support. Works with Bootstrap and AngularJS. Modern, with Material Design themes. The documentation is available on GitHub, which has enabled numerous contributions from users (4500+ commits, 500+ PRs as of Jan 2015).

    enter image description here

    Well-supported commercially, claiming millions of developers, and part of a large family of developer tools. Telerik has received many accolades, is a multi-national company (Bulgaria, US), was acquired by Progress Software, and is a thought leader.

    A Kendo UI Professional developer license costs $700 and posting access to most forums is conditioned upon having a license or being in the trial period.

    [Wikipedia] • GitHub/TelerikDemosPlaygroundTools

  5. OpenUI5 - jQuery-based UI framework with 180 widgets, Apache 2.0-licensed and fully-open sourced and funded by German software giant SAP SE.

    OpenUI5

    The community is much larger than that of Webix, SAP is hiring developers to grow OpenUI5, and they presented OpenUI5 at OSCON 2014.

    The desktop themes are rather lackluster, but the Fiori design for web and mobile looks clean and neat.

    WikipediaGitHubMobile-first controls demosDesktop controls demosSO

  6. DHTMLX - JavaScript library for building rich Web and Mobile apps. Looks most like ExtJS - check the demos. Has been developed since 2005 but still looks modern. All components except TreeGrid are available under GPLv2 but advanced features for many components are only available in the commercial PRO edition - see for example the tree. Claims to be used by many Fortune 500 companies.

    DHTMLX

    Minimal presence on GitHub (the main library code is missing) and StackOverflow but active forum. The documentation is not available on GitHub, which makes it difficult to improve by the community.

  7. Polymer, a Web Components polyfill, plus Polymer Paper, Google's implementation of the Material design. Aimed at web and mobile apps. Doesn't have advanced widgets like trees or even grids but the controls it provides are mobile-first and responsive. Used by many big players, e.g. IBM or USA Today.

    Polymer Paper Elements

  8. Ant Design claims it is "a design language for background applications", influenced by "nature" and helping designers "create low-entropy atmosphere for developer team". That's probably a poor translation from Chinese for "UI components for enterprise web applications". It's a React UI library written in TypeScript, with many components, from simple (buttons, cards) to advanced (autocomplete, calendar, tag input, table).

    The project was born in China, is popular with Chinese companies, and parts of the documentation are available only in Chinese. Quite popular on GitHub, yet it makes the mistake of splitting the community into Chinese and English chat rooms. The design looks Material-ish, but fonts are small and the information looks lost in a see of whitespace.

  9. PrimeUI - collection of 45+ rich widgets based on jQuery UI. Apache 2.0 license. Small GitHub community. 35 premium themes available.

  10. qooxdoo - "a universal JavaScript framework with a coherent set of individual components", developed and funded by German hosting provider 1&1 (see the contributors, one of the world's largest hosting companies. GPL/EPL (a business-friendly license).

    Mobile themes look modern but desktop themes look old (gradients).

    Qooxdoo

    WikipediaGitHubWeb/Mobile/Desktop demosWidgets Demo browserWidget browserSOPlaygroundCommunity

  11. jQuery UI - easy to pick up; looks a bit dated; lacks advanced widgets. Of course, you can combine it with independent widgets for particular needs, e.g. trees or other UI components, but the same can be said for any other framework.

  12. + Angular UI. While Angular is backed by Google, it's being radically revamped in the upcoming 2.0 version, and "users will need to get to grips with a new kind of architecture. It's also been confirmed that there will be no migration path from Angular 1.X to 2.0". Moreover, the consensus seems to be that Angular 2 won't really be ready for use until a year or two from now. Angular UI has relatively few widgets (no trees, for example).

  13. DojoToolkit and their powerful Dijit set of widgets. Completely open-sourced and actively developed on GitHub, but development is now (Nov 2018) focused on the new dojo.io framework, which has very few basic widgets. BSD/AFL license. Development started in 2004 and the Dojo Foundation is being sponsored by IBM, Google, and others - see Wikipedia. 7500 questions here on SO.

    Dojo Dijit

    Themes look desktop-oriented and dated - see the theme tester in dijit. The official theme previewer is broken and only shows "Claro". A Bootstrap theme exists, which looks a lot like Bootstrap, but doesn't use Bootstrap classes. In Jan 2015, I started a thread on building a Material Design theme for Dojo, which got quite popular within the first hours. However, there are questions regarding building that theme for the current Dojo 1.10 vs. the next Dojo 2.0. The response to that thread shows an active and wide community, covering many time zones.

    Unfortunately, Dojo has fallen out of popularity and fewer companies appear to use it, despite having (had?) a strong foothold in the enterprise world. In 2009-2012, its learning curve was steep and the documentation needed improvements; while the documentation has substantially improved, it's unclear how easy it is to pick up Dojo nowadays.

    With a Material Design theme, Dojo (2.0?) might be the killer UI components framework.

    WikipediaGitHubThemesDemosDesktop widgetsSO

  14. Enyo - front-end library aimed at mobile and TV apps (e.g. large touch-friendly controls). Developed by LG Electronix and Apache-licensed on GitHub.

  15. The radical Cappuccino - Objective-J (a superset of JavaScript) instead of HTML+CSS+DOM

  16. Mochaui, MooTools UI Library User Interface Library. <300 GitHub stars.

  17. CrossUI - cross-browser JS framework to develop and package the exactly same code and UI into Web Apps, Native Desktop Apps (Windows, OS X, Linux) and Mobile Apps (iOS, Android, Windows Phone, BlackBerry). Open sourced LGPL3. Featured RAD tool (form builder etc.). The UI looks desktop-, not web-oriented. Actively developed, small community. No presence on GitHub.

  18. ZinoUI - simple widgets. The DataTable, for instance, doesn't even support sorting.

  19. Wijmo - good-looking commercial widgets, with old (jQuery UI) widgets open-sourced on GitHub (their development stopped in 2013). Developed by ComponentOne, a division of GrapeCity. See Wijmo Complete vs. Open.

  20. CxJS - commercial JS framework based on React, Babel and webpack offering form elements, form validation, advanced grid control, navigational elements, tooltips, overlays, charts, routing, layout support, themes, culture dependent formatting and more.

CxJS

Widgets - Demo Apps - Examples - GitHub

Full-stack frameworks

  1. SproutCore - developed by Apple for web applications with native performance, handling large data sets on the client. Powers iCloud.com. Not intended for widgets.

  2. Wakanda: aimed at business/enterprise web apps - see What is Wakanda?. Architecture:

  3. Servoy - "a cross platform frontend development and deployment environment for SQL databases". Boasts a "full WYSIWIG (What You See Is What You Get) UI designer for HTML5 with built-in data-binding to back-end services", responsive design, support for HTML6 Web Components, Websockets and mobile platforms. Written in Java and generates JavaScript code using various JavaBeans.

  4. SmartClient/SmartGWT - mobile and cross-browser HTML5 UI components combined with a Java server. Aimed at building powerful business apps - see demos.

  5. Vaadin - full-stack Java/GWT + JavaScript/HTML3 web app framework

  6. Backbase - portal software

  7. Shiny - front-end library on top R, with visualization, layout and control widgets

  8. ZKOSS: Java+jQuery+Bootstrap framework for building enterprise web and mobile apps.

CSS libraries + minimal widgets

These libraries don't implement complex widgets such as tables with sorting/filtering, autocompletes, or trees.

  1. Bootstrap

  2. Foundation for Apps - responsive front-end framework on top of AngularJS; more of a grid/layout/navigation library

  3. UI Kit - similar to Bootstrap, with fewer widgets, but with official off-canvas.

Libraries using HTML Canvas

Using the canvas elements allows for complete control over the UI, and great cross-browser compatibility, but comes at the cost of missing native browser functionality, e.g. page search via Ctrl/Cmd+F.

  1. Zebra - demos

No longer developed as of Dec 2014

  1. Yahoo! User Interface - YUI, launched in 2005, but no longer maintained by the core contributors - see the announcement, which highlights reasons why large UI widget libraries are perceived as walled gardens that developers don't want to be locked into.
  2. echo3, GitHub. Supports writing either server-side Java applications that don't require developer knowledge of HTML, HTTP, or JavaScript, or client-side JavaScript-based applications do not require a server, but can communicate with one via AJAX. Last update: July 2013.
  3. ampleSDK
  4. Simpler widgets livepipe.net
  5. JxLib
  6. rialto
  7. Simple UI kit
  8. Prototype-ui

Other lists

C#: Dynamic runtime cast

I realize this has been answered, but I used a different approach and thought it might be worth sharing. Also, I feel like my approach might produce unwanted overhead. However, I'm not able to observer or calculate anything happening that is that bad under the loads we observe. I was looking for any useful feedback on this approach.

The problem with working with dynamics is that you can't attach any functions to the dynamic object directly. You have to use something that can figure out the assignments that you don't want to figure out every time.

When planning this simple solution, I looked at what the valid intermediaries are when attempting to retype similar objects. I found that a binary array, string (xml, json) or hard coding a conversion (IConvertable) were the usual approaches. I don't want to get into binary conversions due to a code maintainability factor and laziness.

My theory was that Newtonsoft could do this by using a string intermediary.

As a downside, I am fairly certain that when converting the string to an object, that it would use reflection by searching the current assembly for an object with matching properties, create the type, then instantiate the properties, which would require more reflection. If true, all of this can be considered avoidable overhead.

C#:

//This lives in a helper class
public static ConvertDynamic<T>(dynamic data)
{
     return Newtonsoft.Json.JsonConvert.DeserializeObject<T>(Newtonsoft.Json.JsonConvert.SerializeObject(data));
}

//Same helper, but in an extension class (public static class),
//but could be in a base class also.
public static ToModelList<T>(this List<dynamic> list)
{
    List<T> retList = new List<T>();
    foreach(dynamic d in list)
    {
        retList.Add(ConvertDynamic<T>(d));
    }
}

With that said, this fits another utility I've put together that lets me make any object into a dynamic. I know I had to use reflection to do that correctly:

public static dynamic ToDynamic(this object value)
{
    IDictionary<string, object> expando = new ExpandoObject();

    foreach (PropertyDescriptor property in TypeDescriptor.GetProperties(value.GetType()))
        expando.Add(property.Name, property.GetValue(value));

    return expando as ExpandoObject;
}

I had to offer that function. An arbitrary object assigned to a dynamic typed variable cannot be converted to an IDictionary, and will break the ConvertDynamic function. For this function chain to be used it has to be provided a dynamic of System.Dynamic.ExpandoObject, or IDictionary<string, object>.

Android webview slow

The solution for us was the opposite. We disabled hardware acceleration on the WebView only (rather than on the entire app in the manifest) by using this code:

if (Build.VERSION.SDK_INT >= 11){
    webview.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}

CSS3 animations are smoother now. We are using Android 4.0.

More info here: https://code.google.com/p/android/issues/detail?id=17352

Difference between "\n" and Environment.NewLine

As others have mentioned, Environment.NewLine returns a platform-specific string for beginning a new line, which should be:

  • "\r\n" (\u000D\u000A) for Windows
  • "\n" (\u000A) for Unix
  • "\r" (\u000D) for Mac (if such implementation existed)

Note that when writing to the console, Environment.NewLine is not strictly necessary. The console stream will translate "\n" to the appropriate new-line sequence, if necessary.

How to easily get network path to the file you are working on?

Easiest way to find address path in Excel 2010:

File - info - properties (on right) - (drop-down menu) - advanced properties - general tab

You will get to the same properties box that was so simple to find in Excel 2003.

How to change the window title of a MATLAB plotting figure?

It can also be done this way:

figure(xx);
set(gcf, 'name', 'Name goes here')

gcf gets the current figure handle.

How to use subList()

You could use streams in Java 8. To always get 10 entries at the most, you could do:

dataList.stream().skip(5).limit(10).collect(Collectors.toList());
dataList.stream().skip(30).limit(10).collect(Collectors.toList());

How to use Greek symbols in ggplot2?

You do not need the latex2exp package to do what you wanted to do. The following code would do the trick.

ggplot(smr, aes(Fuel.Rate, Eng.Speed.Ave., color=Eng.Speed.Max.)) + 
  geom_point() + 
  labs(title=expression("Fuel Efficiency"~(alpha*Omega)), 
color=expression(alpha*Omega), x=expression(Delta~price))

enter image description here

Also, some comments (unanswered as of this point) asked about putting an asterisk (*) after a Greek letter. expression(alpha~"*") works, so I suggest giving it a try.

More comments asked about getting ? Price and I find the most straightforward way to achieve that is expression(Delta~price)). If you need to add something before the Greek letter, you can also do this: expression(Indicative~Delta~price) which gets you:

enter image description here

How to delete a file after checking whether it exists

If you are reading from that file using FileStream and then wanting to delete it, make sure you close the FileStream before you call the File.Delete(path). I had this issue.

var filestream = new System.IO.FileStream(@"C:\Test\PutInv.txt", System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.ReadWrite);
filestream.Close();
File.Delete(@"C:\Test\PutInv.txt");

clearing a char array c

Nope. All you are doing is setting the first value to '\0' or 0.

If you are working with null terminated strings, then in the first example, you'll get behavior that mimics what you expect, however the memory is still set.

If you want to clear the memory without using memset, use a for loop.

How to add an image in Tkinter?

It's not a standard lib of python 2.7. So in order for these to work properly and if you're using Python 2.7 you should download the PIL library first: Direct download link: http://effbot.org/downloads/PIL-1.1.7.win32-py2.7.exe After installing it, follow these steps:

  1. Make sure that your script.py is at the same folder with the image you want to show.
  2. Edit your script.py

    from Tkinter import *        
    from PIL import ImageTk, Image
    
    app_root = Tk()
    
    #Setting it up
    img = ImageTk.PhotoImage(Image.open("app.png"))
    
    #Displaying it
    imglabel = Label(app_root, image=img).grid(row=1, column=1)        
    
    
    app_root.mainloop()
    

Hope that helps!

How to explain callbacks in plain english? How are they different from calling one function from another function?

You feel ill so you go to the doctor. He examines you and determines you need some medication. He prescribes some meds and calls the prescription into your local pharmacy. You go home. Later your pharmacy calls to tell you your prescription is ready. You go and pick it up.

Return value using String result=Command.ExecuteScalar() error occurs when result returns null

If the first cell returned is a null, the result in .NET will be DBNull.Value

If no cells are returned, the result in .NET will be null; you cannot call ToString() on a null. You can of course capture what ExecuteScalar returns and process the null / DBNull / other cases separately.

Since you are grouping etc, you presumably could potentially have more than one group. Frankly I'm not sure ExecuteScalar is your best option here...


Additional: the sql in the question is bad in many ways:

  • sql injection
  • internationalization (let's hope the client and server agree on what a date looks like)
  • unnecessary concatenation in separate statements

I strongly suggest you parameterize; perhaps with something like "dapper" to make it easy:

int count = conn.Query<int>(
  @"select COUNT(idemp_atd) absentDayNo from td_atd
    where absentdate_atd between @sdate and @edate
    and idemp_atd=@idemp group by idemp_atd",
    new {sdate, edate, idemp}).FirstOrDefault();

all problems solved, including the "no rows" scenario. The dates are passed as dates (not strings); the injection hole is closed by use of a parameter. You get query-plan re-use as an added bonus, too. The group by here is redundant, BTW - if there is only one group (via the equality condition) you might as well just select COUNT(1).

HTML&CSS + Twitter Bootstrap: full page layout or height 100% - Npx

I've found a post here on Stackoverflow and implemented your design:

http://jsfiddle.net/bKsad/25/

Here's the original post: https://stackoverflow.com/a/5768262/1368423

Is that what you're looking for?

HTML:

<div class="container-fluid wrapper">

  <div class="row-fluid columns content"> 

    <div class="span2 article-tree">
      navigation column
    </div>

    <div class="span10 content-area">
      content column 
    </div>
  </div>

  <div class="footer">
     footer content
  </div>
</div>

CSS:

html, body {
    height: 100%;
}
.container-fluid {
    margin: 0 auto;
    height: 100%;
    padding: 20px 0;

    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

.columns {
    background-color: #C9E6FF;
    height: 100%;   
}

.content-area, .article-tree{
    background: #bada55;
    overflow:auto;
    height: 100%;
}

.footer {
    background: red;
    height: 20px;
}

how to dynamically add options to an existing select in vanilla javascript

.add() also works.

var daySelect = document.getElementById("myDaySelect");
var myOption = document.createElement("option");
myOption.text = "test";
myOption.value = "value";
daySelect.add(option);

W3 School - try

how to get file path from sd card in android

There are different Names of SD-Cards.

This Code check every possible Name (I don't guarantee that these are all names but the most are included)

It prefers the main storage.

 private String SDPath() {
    String sdcardpath = "";

    //Datas
    if (new File("/data/sdext4/").exists() && new File("/data/sdext4/").canRead()){
        sdcardpath = "/data/sdext4/";
    }
    if (new File("/data/sdext3/").exists() && new File("/data/sdext3/").canRead()){
        sdcardpath = "/data/sdext3/";
    }
    if (new File("/data/sdext2/").exists() && new File("/data/sdext2/").canRead()){
        sdcardpath = "/data/sdext2/";
    }
    if (new File("/data/sdext1/").exists() && new File("/data/sdext1/").canRead()){
        sdcardpath = "/data/sdext1/";
    }
    if (new File("/data/sdext/").exists() && new File("/data/sdext/").canRead()){
        sdcardpath = "/data/sdext/";
    }

    //MNTS

    if (new File("mnt/sdcard/external_sd/").exists() && new File("mnt/sdcard/external_sd/").canRead()){
        sdcardpath = "mnt/sdcard/external_sd/";
    }
    if (new File("mnt/extsdcard/").exists() && new File("mnt/extsdcard/").canRead()){
        sdcardpath = "mnt/extsdcard/";
    }
    if (new File("mnt/external_sd/").exists() && new File("mnt/external_sd/").canRead()){
        sdcardpath = "mnt/external_sd/";
    }
    if (new File("mnt/emmc/").exists() && new File("mnt/emmc/").canRead()){
        sdcardpath = "mnt/emmc/";
    }
    if (new File("mnt/sdcard0/").exists() && new File("mnt/sdcard0/").canRead()){
        sdcardpath = "mnt/sdcard0/";
    }
    if (new File("mnt/sdcard1/").exists() && new File("mnt/sdcard1/").canRead()){
        sdcardpath = "mnt/sdcard1/";
    }
    if (new File("mnt/sdcard/").exists() && new File("mnt/sdcard/").canRead()){
        sdcardpath = "mnt/sdcard/";
    }

    //Storages
    if (new File("/storage/removable/sdcard1/").exists() && new File("/storage/removable/sdcard1/").canRead()){
        sdcardpath = "/storage/removable/sdcard1/";
    }
    if (new File("/storage/external_SD/").exists() && new File("/storage/external_SD/").canRead()){
        sdcardpath = "/storage/external_SD/";
    }
    if (new File("/storage/ext_sd/").exists() && new File("/storage/ext_sd/").canRead()){
        sdcardpath = "/storage/ext_sd/";
    }
    if (new File("/storage/sdcard1/").exists() && new File("/storage/sdcard1/").canRead()){
        sdcardpath = "/storage/sdcard1/";
    }
    if (new File("/storage/sdcard0/").exists() && new File("/storage/sdcard0/").canRead()){
        sdcardpath = "/storage/sdcard0/";
    }
    if (new File("/storage/sdcard/").exists() && new File("/storage/sdcard/").canRead()){
        sdcardpath = "/storage/sdcard/";
    }
    if (sdcardpath.contentEquals("")){
        sdcardpath = Environment.getExternalStorageDirectory().getAbsolutePath();
    }

    Log.v("SDFinder","Path: " + sdcardpath);
    return sdcardpath;
}

Using BeautifulSoup to search HTML for string

I have not used BeuatifulSoup but maybe the following can help in some tiny way.

import re
import urllib2
stuff = urllib2.urlopen(your_url_goes_here).read()  # stuff will contain the *entire* page

# Replace the string Python with your desired regex
results = re.findall('(Python)',stuff)

for i in results:
    print i

I'm not suggesting this is a replacement but maybe you can glean some value in the concept until a direct answer comes along.

What does #defining WIN32_LEAN_AND_MEAN exclude exactly?

Complementing the above answers and also "Parroting" from the Windows Dev Center documentation,

The Winsock2.h header file internally includes core elements from the Windows.h header file, so there is not usually an #include line for the Windows.h header file in Winsock applications. If an #include line is needed for the Windows.h header file, this should be preceded with the #define WIN32_LEAN_AND_MEAN macro. For historical reasons, the Windows.h header defaults to including the Winsock.h header file for Windows Sockets 1.1. The declarations in the Winsock.h header file will conflict with the declarations in the Winsock2.h header file required by Windows Sockets 2.0. The WIN32_LEAN_AND_MEAN macro prevents the Winsock.h from being included by the Windows.h header ..

Get age from Birthdate

function getAge(birthday) {
    var today = new Date();
    var thisYear = 0;
    if (today.getMonth() < birthday.getMonth()) {
        thisYear = 1;
    } else if ((today.getMonth() == birthday.getMonth()) && today.getDate() < birthday.getDate()) {
        thisYear = 1;
    }
    var age = today.getFullYear() - birthday.getFullYear() - thisYear;
    return age;
}

JSFiddle

Difference between filter and filter_by in SQLAlchemy

filter_by is used for simple queries on the column names using regular kwargs, like

db.users.filter_by(name='Joe')

The same can be accomplished with filter, not using kwargs, but instead using the '==' equality operator, which has been overloaded on the db.users.name object:

db.users.filter(db.users.name=='Joe')

You can also write more powerful queries using filter, such as expressions like:

db.users.filter(or_(db.users.name=='Ryan', db.users.country=='England'))

Quotation marks inside a string

You can do this using Escape Sequence.

\"

So you will have to write something like this :

String name = "\"john\"";

You can learn about Escape Sequences from here.

Get client IP address via third party web service

This pulls back client info as well.

var get = function(u){
    var x = new XMLHttpRequest;
    x.open('GET', u, false);
    x.send();
    return x.responseText;
}

JSON.parse(get('http://ifconfig.me/all.json'))

What's the difference between JPA and Hibernate?

From the Wiki.

Motivation for creating the Java Persistence API

Many enterprise Java developers use lightweight persistent objects provided by open-source frameworks or Data Access Objects instead of entity beans: entity beans and enterprise beans had a reputation of being too heavyweight and complicated, and one could only use them in Java EE application servers. Many of the features of the third-party persistence frameworks were incorporated into the Java Persistence API, and as of 2006 projects like Hibernate (version 3.2) and Open-Source Version TopLink Essentials have become implementations of the Java Persistence API.

As told in the JCP page the Eclipse link is the Reference Implementation for JPA. Have look at this answer for bit more on this.

JPA itself has features that will make up for a standard ORM framework. Since JPA is a part of Java EE spec, you can use JPA alone in a project and it should work with any Java EE compatible Servers. Yes, these servers will have the implementations for the JPA spec.

Hibernate is the most popular ORM framework, once the JPA got introduced hibernate conforms to the JPA specifications. Apart from the basic set of specification that it should follow hibernate provides whole lot of additional stuff.

Exception: Unexpected end of ZLIB input stream

You have to call close() on the GZIPOutputStream before you attempt to read it. The final bytes of the file will only be written when the file is actually closed. (This is irrespective of any explicit buffering in the output stack. The stream only knows to compress and write the last bytes when you tell it to close. A flush() probably won't help ... though calling finish() instead of close() should work. Look at the javadocs.)

Here's the correct code (in Java);

package test;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GZipTest {

    public static void main(String[] args) throws
                FileNotFoundException, IOException {
        String name = "/tmp/test";
        GZIPOutputStream gz = new GZIPOutputStream(new FileOutputStream(name));
        gz.write(10);
        gz.close();       // Remove this to reproduce the reported bug
        System.out.println(new GZIPInputStream(new FileInputStream(name)).read());
    }
}

(I've not implemented resource management or exception handling / reporting properly as they are not relevant to the purpose of this code. Don't treat this as an example of "good code".)

C++ How do I convert a std::chrono::time_point to long and back

std::chrono::time_point<std::chrono::system_clock> now = std::chrono::system_clock::now();

This is a great place for auto:

auto now = std::chrono::system_clock::now();

Since you want to traffic at millisecond precision, it would be good to go ahead and covert to it in the time_point:

auto now_ms = std::chrono::time_point_cast<std::chrono::milliseconds>(now);

now_ms is a time_point, based on system_clock, but with the precision of milliseconds instead of whatever precision your system_clock has.

auto epoch = now_ms.time_since_epoch();

epoch now has type std::chrono::milliseconds. And this next statement becomes essentially a no-op (simply makes a copy and does not make a conversion):

auto value = std::chrono::duration_cast<std::chrono::milliseconds>(epoch);

Here:

long duration = value.count();

In both your and my code, duration holds the number of milliseconds since the epoch of system_clock.

This:

std::chrono::duration<long> dur(duration);

Creates a duration represented with a long, and a precision of seconds. This effectively reinterpret_casts the milliseconds held in value to seconds. It is a logic error. The correct code would look like:

std::chrono::milliseconds dur(duration);

This line:

std::chrono::time_point<std::chrono::system_clock> dt(dur);

creates a time_point based on system_clock, with the capability of holding a precision to the system_clock's native precision (typically finer than milliseconds). However the run-time value will correctly reflect that an integral number of milliseconds are held (assuming my correction on the type of dur).

Even with the correction, this test will (nearly always) fail though:

if (dt != now)

Because dt holds an integral number of milliseconds, but now holds an integral number of ticks finer than a millisecond (e.g. microseconds or nanoseconds). Thus only on the rare chance that system_clock::now() returned an integral number of milliseconds would the test pass.

But you can instead:

if (dt != now_ms)

And you will now get your expected result reliably.

Putting it all together:

int main ()
{
    auto now = std::chrono::system_clock::now();
    auto now_ms = std::chrono::time_point_cast<std::chrono::milliseconds>(now);

    auto value = now_ms.time_since_epoch();
    long duration = value.count();

    std::chrono::milliseconds dur(duration);

    std::chrono::time_point<std::chrono::system_clock> dt(dur);

    if (dt != now_ms)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

Personally I find all the std::chrono overly verbose and so I would code it as:

int main ()
{
    using namespace std::chrono;
    auto now = system_clock::now();
    auto now_ms = time_point_cast<milliseconds>(now);

    auto value = now_ms.time_since_epoch();
    long duration = value.count();

    milliseconds dur(duration);

    time_point<system_clock> dt(dur);

    if (dt != now_ms)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

Which will reliably output:

Success.

Finally, I recommend eliminating temporaries to reduce the code converting between time_point and integral type to a minimum. These conversions are dangerous, and so the less code you write manipulating the bare integral type the better:

int main ()
{
    using namespace std::chrono;
    // Get current time with precision of milliseconds
    auto now = time_point_cast<milliseconds>(system_clock::now());
    // sys_milliseconds is type time_point<system_clock, milliseconds>
    using sys_milliseconds = decltype(now);
    // Convert time_point to signed integral type
    auto integral_duration = now.time_since_epoch().count();
    // Convert signed integral type to time_point
    sys_milliseconds dt{milliseconds{integral_duration}};
    // test
    if (dt != now)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

The main danger above is not interpreting integral_duration as milliseconds on the way back to a time_point. One possible way to mitigate that risk is to write:

    sys_milliseconds dt{sys_milliseconds::duration{integral_duration}};

This reduces risk down to just making sure you use sys_milliseconds on the way out, and in the two places on the way back in.

And one more example: Let's say you want to convert to and from an integral which represents whatever duration system_clock supports (microseconds, 10th of microseconds or nanoseconds). Then you don't have to worry about specifying milliseconds as above. The code simplifies to:

int main ()
{
    using namespace std::chrono;
    // Get current time with native precision
    auto now = system_clock::now();
    // Convert time_point to signed integral type
    auto integral_duration = now.time_since_epoch().count();
    // Convert signed integral type to time_point
    system_clock::time_point dt{system_clock::duration{integral_duration}};
    // test
    if (dt != now)
        std::cout << "Failure." << std::endl;
    else
        std::cout << "Success." << std::endl;
}

This works, but if you run half the conversion (out to integral) on one platform and the other half (in from integral) on another platform, you run the risk that system_clock::duration will have different precisions for the two conversions.

Run chrome in fullscreen mode on Windows

I would like to share my way of starting chrome - specificaly youtube tv - in full screen mode automatically, without the need of pressing F11. kiosk/fullscreen options doesn't seem to work (Version 41.0.2272.89). It has some steps though...

  • Start chrome and navigate to page (www.youtube.com/tv)
  • Drag the address from the address bar (the lock icon) to the desktop. It will create a shortcut.
  • From chrome, open Apps (the icon with the multiple coloured dots)
  • From desktop, drag the shortcut into the Apps space
  • Right click on the new icon in Apps and select "Open fullscreen"
  • Right click again on the icon in Apps and select "Create shortcuts..."
  • Select for example Desktop and Create. A new shortcut will be created on desktop.

Now, whenever you click on this shortcut, chrome will start in fullscreen and at the page you defined. I guess you can put this shortcut in startup folder to run when windows starts, but I haven't tried it.

@HostBinding and @HostListener: what do they do and what are they for?

Have you checked these official docs?

HostListener - Declares a host listener. Angular will invoke the decorated method when the host element emits the specified event.

@HostListener - will listen to the event emitted by the host element that's declared with @HostListener.

HostBinding - Declares a host property binding. Angular automatically checks host property bindings during change detection. If a binding changes, it will update the host element of the directive.

@HostBinding - will bind the property to the host element, If a binding changes, HostBinding will update the host element.


NOTE: Both links have been removed recently. The "HostBinding-HostListening" portion of the style guide may be a useful alternative until the links return.


Here's a simple code example to help picture what this means:

DEMO : Here's the demo live in plunker - "A simple example about @HostListener & @HostBinding"

  • This example binds a role property -- declared with @HostBinding -- to the host's element
    • Recall that role is an attribute, since we're using attr.role.
    • <p myDir> becomes <p mydir="" role="admin"> when you view it in developer tools.
  • It then listens to the onClick event declared with @HostListener, attached to the component's host element, changing role with each click.
    • The change when the <p myDir> is clicked is that its opening tag changes from <p mydir="" role="admin"> to <p mydir="" role="guest"> and back.

directives.ts

import {Component,HostListener,Directive,HostBinding,Input} from '@angular/core';

@Directive({selector: '[myDir]'})
export class HostDirective {
  @HostBinding('attr.role') role = 'admin'; 
  @HostListener('click') onClick() {
    this.role= this.role === 'admin' ? 'guest' : 'admin';
  }
}

AppComponent.ts

import { Component,ElementRef,ViewChild } from '@angular/core';
import {HostDirective} from './directives';

@Component({
selector: 'my-app',
template:
  `
  <p myDir>Host Element 
    <br><br>

    We have a (HostListener) listening to this host's <b>click event</b> declared with @HostListener

    <br><br>

    And we have a (HostBinding) binding <b>the role property</b> to host element declared with @HostBinding 
    and checking host's property binding updates.

    If any property change is found I will update it.
  </p>

  <div>View this change in the DOM of the host element by opening developer tools,
    clicking the host element in the UI. 

    The role attribute's changes will be visible in the DOM.</div> 
    `,
  directives: [HostDirective]
})
export class AppComponent {}

How do I compile a .c file on my Mac?

Just for the record in modern times,

for 2017 !

1 - Just have updated Xcode on your machine as you normally do

2 - Open terminal and

$ xcode-select --install

it will perform a short install of a minute or two.

3 - Launch Xcode. "New" "Project" ... you have to choose "Command line tool"

Note - confusingly this is under the "macOS" tab.

choose this one

Select "C" language on the next screen...

enter image description here

4- You'll be asked to save the project somewhere on your desktop. The name you give the project here is just the name of the folder that will hold the project. It does not have any importance in the actual software.

5 - You're golden! You can now enjoy c with Mac and Xcode.

you're golden

How to access parent Iframe from JavaScript

// just in case some one is searching for a solution
function get_parent_frame_dom_element(win)
{
    win = (win || window);
    var parentJQuery = window.parent.jQuery;
    var ifrms = parentJQuery("iframe.upload_iframe");
    for (var i = 0; i < ifrms.length; i++)
    {
        if (ifrms[i].contentDocument === win.document)
            return ifrms[i];
    }
    return null;
}

"unary operator expected" error in Bash if condition

Took me a while to find this but note that if you have a spacing error you will also get the same error:

[: =: unary operator expected

Correct:

if [ "$APP_ENV" = "staging" ]

vs

if ["$APP_ENV" = "staging" ]

As always setting -x debug variable helps to find these:

set -x

How can I check if a directory exists?

You may also use access in combination with opendir to determine if the directory exists, and, if the name exists, but is not a directory. For example:

/* test that dir exists (1 success, -1 does not exist, -2 not dir) */
int
xis_dir (const char *d)
{
    DIR *dirptr;

    if (access ( d, F_OK ) != -1 ) {
        // file exists
        if ((dirptr = opendir (d)) != NULL) {
            closedir (dirptr); /* d exists and is a directory */
        } else {
            return -2; /* d exists but is not a directory */
        }
    } else {
        return -1;     /* d does not exist */
    }

    return 1;
}

Return file in ASP.Net Core Web API

Here is a simplistic example of streaming a file:

using System.IO;
using Microsoft.AspNetCore.Mvc;
[HttpGet("{id}")]
public async Task<FileStreamResult> Download(int id)
{
    var path = "<Get the file path using the ID>";
    var stream = File.OpenRead(path);
    return new FileStreamResult(stream, "application/octet-stream");
}

Note:

Be sure to use FileStreamResult from Microsoft.AspNetCore.Mvc and not from System.Web.Mvc.

How do I make the scrollbar on a div only visible when necessary?

try

<div style='overflow:auto; width:400px;height:400px;'>here is some text</div>

Set the intervals of x-axis using r

You can use axis:

> axis(side=1, at=c(0:23))

That is, something like this:

plot(0:23, d, type='b', axes=FALSE)
axis(side=1, at=c(0:23))
axis(side=2, at=seq(0, 600, by=100))
box()

Android ADT error, dx.jar was not loaded from the SDK folder

It happened to me, either, and it happens because I've changed to win7, and install the latest ADT to eclipse, but I used my old Android SDK. Finally, I fix this problem by updating my Android SDK to the latest version.

How to change cursor from pointer to finger using jQuery?

Update! New & improved! Find plugin @ GitHub!


On another note, while that method is simple, I've created a jQuery plug (found at this jsFiddle, just copy and past code between comment lines) that makes changing the cursor on any element as simple as $("element").cursor("pointer").

But that's not all! Act now and you'll get the hand functions position & ishover for no extra charge! That's right, 2 very handy cursor functions ... FREE!

They work as simple as seen in the demo:

$("h3").cursor("isHover"); // if hovering over an h3 element, will return true, 
    // else false
// also handy as
$("h2, h3").cursor("isHover"); // unless your h3 is inside an h2, this will be 
    // false as it checks to see if cursor is hovered over both elements, not just the last!
//  And to make this deal even sweeter - use the following to get a jQuery object
//       of ALL elements the cursor is currently hovered over on demand!
$.cursor("isHover");

Also:

$.cursor("position"); // will return the current cursor position as { x: i, y: i }
    // at anytime you call it!

Supplies are limited, so Act Now!

Bash: Echoing a echo command with a variable in bash

You just need to use single quotes:

$ echo "$TEST"
test
$ echo '$TEST'
$TEST

Inside single quotes special characters are not special any more, they are just normal characters.

How to disable RecyclerView scrolling?

Wrote a kotlin version:

class NoScrollLinearLayoutManager(context: Context?) : LinearLayoutManager(context) {
    private var scrollable = true

    fun enableScrolling() {
        scrollable = true
    }

    fun disableScrolling() {
        scrollable = false
    }

    override fun canScrollVertically() =
            super.canScrollVertically() && scrollable


    override fun canScrollHorizontally() =
            super.canScrollVertically()

 && scrollable
}

usage:

recyclerView.layoutManager = NoScrollLinearLayoutManager(context)
(recyclerView.layoutManager as NoScrollLinearLayoutManager).disableScrolling()

PHP array() to javascript array()

You should need to convert your PHP array to javascript array using PHP syntax json_encode. json_encode convert PHP array to JSON string

Single Dimension PHP array to javascript array

<?php
var $itemsarray= array("Apple", "Bear", "Cat", "Dog");
?>
<script>
var items= <?php echo json_encode($itemsarray); ?>;
console.log(items[2]); // Output: Bear
// OR
alert(items[0]); // Output: Apple
</script>

Multi Dimension PHP array to javascript array

<?php
var $itemsarray= array( 
               array('name'='Apple', 'price'=>'12345'),
               array('name'='Bear', 'price'=>'13344'),
               array('name'='Potato', 'price'=>'00440')
             );
?>


<script>
var items= <?php echo json_encode($itemsarray); ?>;
console.log(items[1][name]); // Output: Bear
// OR
alert(items[0][price]); // Output: Apple
</script>

For more detail, you can also check php array to javascript array

Converting bool to text in C++

How about using the C++ language itself?

bool t = true;
bool f = false;
std::cout << std::noboolalpha << t << " == " << std::boolalpha << t << std::endl;        
std::cout << std::noboolalpha << f << " == " << std::boolalpha << f << std::endl;

UPDATE:

If you want more than 4 lines of code without any console output, please go to cppreference.com's page talking about std::boolalpha and std::noboolalpha which shows you the console output and explains more about the API.

Additionally using std::boolalpha will modify the global state of std::cout, you may want to restore the original behavior go here for more info on restoring the state of std::cout.

Create boolean column in MySQL with false as default value?

You can set a default value at creation time like:

CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
Married boolean DEFAULT false);

Non-numeric Argument to Binary Operator Error in R

Because your question is phrased regarding your error message and not whatever your function is trying to accomplish, I will address the error.

- is the 'binary operator' your error is referencing, and either CurrentDay or MA (or both) are non-numeric.

A binary operation is a calculation that takes two values (operands) and produces another value (see wikipedia for more). + is one such operator: "1 + 1" takes two operands (1 and 1) and produces another value (2). Note that the produced value isn't necessarily different from the operands (e.g., 1 + 0 = 1).

R only knows how to apply + (and other binary operators, such as -) to numeric arguments:

> 1 + 1
[1] 2
> 1 + 'one'
Error in 1 + "one" : non-numeric argument to binary operator

When you see that error message, it means that you are (or the function you're calling is) trying to perform a binary operation with something that isn't a number.

EDIT:

Your error lies in the use of [ instead of [[. Because Day is a list, subsetting with [ will return a list, not a numeric vector. [[, however, returns an object of the class of the item contained in the list:

> Day <- Transaction(1, 2)["b"]
> class(Day)
[1] "list"
> Day + 1
Error in Day + 1 : non-numeric argument to binary operator

> Day2 <- Transaction(1, 2)[["b"]]
> class(Day2)
[1] "numeric"
> Day2 + 1
[1] 3

Transaction, as you've defined it, returns a list of two vectors. Above, Day is a list contain one vector. Day2, however, is simply a vector.

Simple DateTime sql query

You can execute below code

SELECT Time FROM [TableName] where DATEPART(YYYY,[Time])='2018' and DATEPART(MM,[Time])='06' and DATEPART(DD,[Time])='14

How can I check if a string only contains letters in Python?

(1) Use str.isalpha() when you print the string.

(2) Please check below program for your reference:-

 str = "this";  # No space & digit in this string
 print str.isalpha() # it gives return True

 str = "this is 2";
 print str.isalpha() # it gives return False

Note:- I checked above example in Ubuntu.

How may I sort a list alphabetically using jQuery?

$(".list li").sort(asc_sort).appendTo('.list');
//$("#debug").text("Output:");
// accending sort
function asc_sort(a, b){
    return ($(b).text()) < ($(a).text()) ? 1 : -1;    
}

// decending sort
function dec_sort(a, b){
    return ($(b).text()) > ($(a).text()) ? 1 : -1;    
}

live demo : http://jsbin.com/eculis/876/edit

Difference between static memory allocation and dynamic memory allocation

Static memory allocation. Memory allocated will be in stack.

int a[10];

Dynamic memory allocation. Memory allocated will be in heap.

int *a = malloc(sizeof(int) * 10);

and the latter should be freed since there is no Garbage Collector(GC) in C.

free(a);

SQL Server: UPDATE a table by using ORDER BY

No.

Not a documented 100% supported way. There is an approach sometimes used for calculating running totals called "quirky update" that suggests that it might update in order of clustered index if certain conditions are met but as far as I know this relies completely on empirical observation rather than any guarantee.

But what version of SQL Server are you on? If SQL2005+ you might be able to do something with row_number and a CTE (You can update the CTE)

With cte As
(
SELECT id,Number,
ROW_NUMBER() OVER (ORDER BY id DESC) AS RN
FROM Test
)
UPDATE cte SET Number=RN

How to add Date Picker Bootstrap 3 on MVC 5 project using the Razor engine?

Checkout Shield UI's Date Picker for MVC. A powerful component that you can integrate with a few lines like:

@(Html.ShieldDatePicker()
    .Name("datepicker"))

Download multiple files as a zip-file using php

You can use the ZipArchive class to create a ZIP file and stream it to the client. Something like:

$files = array('readme.txt', 'test.html', 'image.gif');
$zipname = 'file.zip';
$zip = new ZipArchive;
$zip->open($zipname, ZipArchive::CREATE);
foreach ($files as $file) {
  $zip->addFile($file);
}
$zip->close();

and to stream it:

header('Content-Type: application/zip');
header('Content-disposition: attachment; filename='.$zipname);
header('Content-Length: ' . filesize($zipname));
readfile($zipname);

The second line forces the browser to present a download box to the user and prompts the name filename.zip. The third line is optional but certain (mainly older) browsers have issues in certain cases without the content size being specified.

Check if a string has a certain piece of text

Here you go: ES5

var test = 'Hello World';
if( test.indexOf('World') >= 0){
  // Found world
}

With ES6 best way would be to use includes function to test if the string contains the looking work.

const test = 'Hello World';
if (test.includes('World')) { 
  // Found world
}

Angular 4 img src is not found

You must use this code in angular to add the image path. if your images are under assets folder then.

<img src="../assets/images/logo.png" id="banner-logo" alt="Landing Page"/>

if not under the assets folder then you can use this code.

<img src="../images/logo.png" id="banner-logo" alt="Landing Page"/>

Automatically deleting related rows in Laravel (Eloquent ORM)

Relation in User model:

public function photos()
{
    return $this->hasMany('Photo');
}

Delete record and related:

$user = User::find($id);

// delete related   
$user->photos()->delete();

$user->delete();

Use of 'prototype' vs. 'this' in JavaScript?

The examples have very different outcomes.

Before looking at the differences, the following should be noted:

  • A constructor's prototype provides a way to share methods and values among instances via the instance's private [[Prototype]] property.
  • A function's this is set by how the function is called or by the use of bind (not discussed here). Where a function is called on an object (e.g. myObj.method()) then this within the method references the object. Where this is not set by the call or by the use of bind, it defaults to the global object (window in a browser) or in strict mode, remains undefined.
  • JavaScript is an object-oriented language, i.e. most values are objects, including functions. (Strings, numbers, and booleans are not objects.)

So here are the snippets in question:

var A = function () {
    this.x = function () {
        //do something
    };
};

In this case, variable A is assigned a value that is a reference to a function. When that function is called using A(), the function's this isn't set by the call so it defaults to the global object and the expression this.x is effective window.x. The result is that a reference to the function expression on the right-hand side is assigned to window.x.

In the case of:

var A = function () { };
A.prototype.x = function () {
    //do something
};

something very different occurs. In the first line, variable A is assigned a reference to a function. In JavaScript, all functions objects have a prototype property by default so there is no separate code to create an A.prototype object.

In the second line, A.prototype.x is assigned a reference to a function. This will create an x property if it doesn't exist, or assign a new value if it does. So the difference with the first example in which object's x property is involved in the expression.

Another example is below. It's similar to the first one (and maybe what you meant to ask about):

var A = new function () {
    this.x = function () {
        //do something
    };
};

In this example, the new operator has been added before the function expression so that the function is called as a constructor. When called with new, the function's this is set to reference a new Object whose private [[Prototype]] property is set to reference the constructor's public prototype. So in the assignment statement, the x property will be created on this new object. When called as a constructor, a function returns its this object by default, so there is no need for a separate return this; statement.

To check that A has an x property:

console.log(A.x) // function () {
                 //   //do something
                 // };

This is an uncommon use of new since the only way to reference the constructor is via A.constructor. It would be much more common to do:

var A = function () {
    this.x = function () {
        //do something
    };
};
var a = new A();

Another way of achieving a similar result is to use an immediately invoked function expression:

var A = (function () {
    this.x = function () {
        //do something
    };
}());

In this case, A assigned the return value of calling the function on the right-hand side. Here again, since this is not set in the call, it will reference the global object and this.x is effective window.x. Since the function doesn't return anything, A will have a value of undefined.

These differences between the two approaches also manifest if you're serializing and de-serializing your Javascript objects to/from JSON. Methods defined on an object's prototype are not serialized when you serialize the object, which can be convenient when for example you want to serialize just the data portions of an object, but not it's methods:

var A = function () { 
    this.objectsOwnProperties = "are serialized";
};
A.prototype.prototypeProperties = "are NOT serialized";
var instance = new A();
console.log(instance.prototypeProperties); // "are NOT serialized"
console.log(JSON.stringify(instance)); 
// {"objectsOwnProperties":"are serialized"} 

Related questions:

Sidenote: There may not be any significant memory savings between the two approaches, however using the prototype to share methods and properties will likely use less memory than each instance having its own copy.

JavaScript isn't a low-level language. It may not be very valuable to think of prototyping or other inheritance patterns as a way to explicitly change the way memory is allocated.

What is the meaning of single and double underscore before an object name?

Great answers and all are correct.I have provided simple example along with simple definition/meaning.

Meaning:

some_variable --? it's public anyone can see this.

_some_variable --? it's public anyone can see this but it's a convention to indicate private...warning no enforcement is done by Python.

__some_varaible --? Python replaces the variable name with _classname__some_varaible (AKA name mangling) and it reduces/hides it's visibility and be more like private variable.

Just to be honest here According to Python documentation

"“Private” instance variables that cannot be accessed except from inside an object don’t exist in Python"

The example:

class A():
    here="abc"
    _here="_abc"
    __here="__abc"


aObject=A()
print(aObject.here) 
print(aObject._here)
# now if we try to print __here then it will fail because it's not public variable 
#print(aObject.__here)

Installing packages in Sublime Text 2

This recently worked for me. You just need to add to your packages, so that the package manager would be aware of the packages:

  1. Add the Sublime Text 2 Repository to your Synaptic Package Manager:

    sudo add-apt-repository ppa:webupd8team/sublime-text-2
    
  2. Update

    sudo apt-get update
    
  3. Install Sublime Text:

    sudo apt-get install sublime-text
    

Access Control Request Headers, is added to header in AJAX request with jQuery

And that is why you can't create a bot with JavaScript, because your options are limited to what the browser allows you to do. You can't just order a browser that follows the CORS policy, which most browsers follow, to send random requests to other origins and allow you to get the response that simply!

Additionally, if you tried to edit some request headers manually, like origin-header from the developers tools that come with the browsers, the browser will refuse your edit and may send a preflight OPTIONS request.

In Python, how do I split a string and keep the separators?

>>> re.split('(\W)', 'foo/bar spam\neggs')
['foo', '/', 'bar', ' ', 'spam', '\n', 'eggs']

What is define([ , function ]) in JavaScript?

define() is part of the AMD spec of js

See:

Edit: Also see Claudio's answer below. Likely the more relevant explanation.

Generate random numbers using C++11 random library

My 'random' library provide a high convenient wrapper around C++11 random classes. You can do almost all things with a simple 'get' method.

Examples:

  1. Random number in a range

    auto val = Random::get(-10, 10); // Integer
    auto val = Random::get(10.f, -10.f); // Float point
    
  2. Random boolean

    auto val = Random::get<bool>( ) // 50% to generate true
    auto val = Random::get<bool>( 0.7 ) // 70% to generate true
    
  3. Random value from a std::initilizer_list

    auto val = Random::get( { 1, 3, 5, 7, 9 } ); // val = 1 or 3 or...
    
  4. Random iterator from iterator range or all container

    auto it = Random::get( vec.begin(), vec.end() ); // it = random iterator
    auto it = Random::get( vec ); // return random iterator
    

And even more things ! Check out the github page:

https://github.com/effolkronium/random

How to delete the last row of data of a pandas dataframe

Since index positioning in Python is 0-based, there won't actually be an element in index at the location corresponding to len(DF). You need that to be last_row = len(DF) - 1:

In [49]: dfrm
Out[49]: 
          A         B         C
0  0.120064  0.785538  0.465853
1  0.431655  0.436866  0.640136
2  0.445904  0.311565  0.934073
3  0.981609  0.695210  0.911697
4  0.008632  0.629269  0.226454
5  0.577577  0.467475  0.510031
6  0.580909  0.232846  0.271254
7  0.696596  0.362825  0.556433
8  0.738912  0.932779  0.029723
9  0.834706  0.002989  0.333436

[10 rows x 3 columns]

In [50]: dfrm.drop(dfrm.index[len(dfrm)-1])
Out[50]: 
          A         B         C
0  0.120064  0.785538  0.465853
1  0.431655  0.436866  0.640136
2  0.445904  0.311565  0.934073
3  0.981609  0.695210  0.911697
4  0.008632  0.629269  0.226454
5  0.577577  0.467475  0.510031
6  0.580909  0.232846  0.271254
7  0.696596  0.362825  0.556433
8  0.738912  0.932779  0.029723

[9 rows x 3 columns]

However, it's much simpler to just write DF[:-1].

http://localhost:50070 does not work HADOOP

There is a similar question and answer at: Start Hadoop 50075 Port is not resolved

Take a look at your core-site.xml file to determine which port it is set to. If 0, it will randomly pick a port, so be sure to set one.

What does "\r" do in the following script?

The '\r' character is the carriage return, and the carriage return-newline pair is both needed for newline in a network virtual terminal session.


From the old telnet specification (RFC 854) (page 11):

The sequence "CR LF", as defined, will cause the NVT to be positioned at the left margin of the next print line (as would, for example, the sequence "LF CR").

However, from the latest specification (RFC5198) (page 13):

  1. ...

  2. In Net-ASCII, CR MUST NOT appear except when immediately followed by either NUL or LF, with the latter (CR LF) designating the "new line" function. Today and as specified above, CR should generally appear only when followed by LF. Because page layout is better done in other ways, because NUL has a special interpretation in some programming languages, and to avoid other types of confusion, CR NUL should preferably be avoided as specified above.

  3. LF CR SHOULD NOT appear except as a side-effect of multiple CR LF sequences (e.g., CR LF CR LF).

So newline in Telnet should always be '\r\n' but most implementations have either not been updated, or keeps the old '\n\r' for backwards compatibility.

MySQL - how to front pad zip code with "0"?

It would still make sense to create your zip code field as a zerofilled unsigned integer field.

CREATE TABLE xxx ( zipcode INT(5) ZEROFILL UNSIGNED, ... )

That way mysql takes care of the padding for you.

What exactly is the 'react-scripts start' command?

create-react-app and react-scripts

react-scripts is a set of scripts from the create-react-app starter pack. create-react-app helps you kick off projects without configuring, so you do not have to setup your project by yourself.

react-scripts start sets up the development environment and starts a server, as well as hot module reloading. You can read here to see what everything it does for you.

with create-react-app you have following features out of the box.

  • React, JSX, ES6, and Flow syntax support.
  • Language extras beyond ES6 like the object spread operator.
  • Autoprefixed CSS, so you don’t need -webkit- or other prefixes.
  • A fast interactive unit test runner with built-in support for coverage reporting.
  • A live development server that warns about common mistakes.
  • A build script to bundle JS, CSS, and images for production, with hashes and sourcemaps.
  • An offline-first service worker and a web app manifest, meeting all the Progressive Web App criteria.
  • Hassle-free updates for the above tools with a single dependency.

npm scripts

npm start is a shortcut for npm run start.

npm run is used to run scripts that you define in the scripts object of your package.json

if there is no start key in the scripts object, it will default to node server.js

Sometimes you want to do more than the react scripts gives you, in this case you can do react-scripts eject. This will transform your project from a "managed" state into a not managed state, where you have full control over dependencies, build scripts and other configurations.

How can I add 1 day to current date?

Inspired by jpmottin in this question, here's the one line code:

_x000D_
_x000D_
var dateStr = '2019-01-01';_x000D_
var days = 1;_x000D_
_x000D_
var result = new Date(new Date(dateStr).setDate(new Date(dateStr).getDate() + days));_x000D_
_x000D_
document.write('Date: ', result); // Wed Jan 02 2019 09:00:00 GMT+0900 (Japan Standard Time)_x000D_
document.write('<br />');_x000D_
document.write('Trimmed Date: ', result.toISOString().substr(0, 10)); // 2019-01-02
_x000D_
_x000D_
_x000D_

Hope this helps

How to change an element's title attribute using jQuery

As an addition to @C??? answer, make sure the title of the tooltip has not already been set manually in the HTML element. In my case, the span class for the tooltip already had a fixed tittle text, because of this my JQuery function $('[data-toggle="tooltip"]').prop('title', 'your new title'); did not work.

When I removed the title attribute in the HTML span class, the jQuery was working.

So:

<span class="showTooltip" data-target="#showTooltip" data-id="showTooltip">
      <span id="MyTooltip" class="fas fa-info-circle" data-toggle="tooltip" data-placement="top" title="this is my pre-set title text"></span>
</span>

Should becode:

<span class="showTooltip" data-target="#showTooltip" data-id="showTooltip">
      <span id="MyTooltip" class="fas fa-info-circle" data-toggle="tooltip" data-placement="top"></span>
</span>

Remove all html tags from php string

use strip_tags

$text = '<p>Test paragraph.</p><!-- Comment --> <a href="#fragment">Other text</a>';
echo strip_tags($text);   //output Test paragraph. Other text

<?php echo substr(strip_tags($row_get_Business['business_description']),0,110) . "..."; ?>

How to delete object from array inside foreach loop?

foreach($array as $elementKey => $element) {
    foreach($element as $valueKey => $value) {
        if($valueKey == 'id' && $value == 'searched_value'){
            //delete this particular object from the $array
            unset($array[$elementKey]);
        } 
    }
}

Testing the type of a DOM element in JavaScript

Perhaps you'll have to check the nodetype too:

if(element.nodeType == 1){//element of type html-object/tag
  if(element.tagName=="a"){
    //this is an a-element
  }
  if(element.tagName=="div"){
    //this is a div-element
  }
}

Edit: Corrected the nodeType-value

Why does this AttributeError in python occur?

This happens because the scipy module doesn't have any attribute named sparse. That attribute only gets defined when you import scipy.sparse.

Submodules don't automatically get imported when you just import scipy; you need to import them explicitly. The same holds for most packages, although a package can choose to import its own submodules if it wants to. (For example, if scipy/__init__.py included a statement import scipy.sparse, then the sparse submodule would be imported whenever you import scipy.)

GUI Tool for PostgreSQL

There is a comprehensive list of tools on the PostgreSQL Wiki:

https://wiki.postgresql.org/wiki/PostgreSQL_Clients

And of course PostgreSQL itself comes with pgAdmin, a GUI tool for accessing Postgres databases.

Looping through all the properties of object php

Here is another way to express the object property.

foreach ($obj as $key=>$value) {
    echo "$key => $obj[$key]\n";
}

Vertical Align text in a Label

Have you tried line-height? It won't solve your problems if there are multiple row labels, but it can be a quick solution.

python pandas dataframe to dictionary

If you want a simple way to preserve duplicates, you could use groupby:

>>> ptest = pd.DataFrame([['a',1],['a',2],['b',3]], columns=['id', 'value']) 
>>> ptest
  id  value
0  a      1
1  a      2
2  b      3
>>> {k: g["value"].tolist() for k,g in ptest.groupby("id")}
{'a': [1, 2], 'b': [3]}

Copy files on Windows Command Line with Progress

Some interesting timings regarding all these methods. If you have Gigabit connections, you should not use the /z flag or it will kill your connection speed. Robocopy or dism are the only tools that go full speed and show a progress bar. wdscase is for multicasting off a WDS server and might be faster if you are imaging 5+ computers. To get the 1:17 timing, I was maxing out the Gigabit connection at 920Mbps so you won't get that on two connections at once. Also take note that exporting the small wim index out of the larger wim file too longer than just copying the whole thing.

Model  Exe       OS       switches     index    size    time   link speed 
8760w  dism      Win8     /export-wim  index 1  6.27GB  2:21   link 1Gbps
8760w  dism      Win8     /export-wim  index 2  7.92GB  1:29   link 1Gbps
6305   wdsmcast  winpe32  /trans-file  res.RWM  7.92GB  6:54   link 1Gbps
6305   dism      Winpe32  /export-wim  index 1  6.27GB  2:20   link 1Gbps
6305   dism      Winpe32  /export-wim  index 2  7.92GB  1:34   link 1Gbps
6305   copy      Winpe32  /z           Whole    7.92GB  25:48  link 1Gbps
6305   copy      Winpe32  none         Wim      7.92GB  1:17   link 1Gbps
6305   xcopy     Winpe32  /z /j        Wim      7.92GB  23:54  link 1Gbps
6305   xcopy     Winpe32  /j           Wim      7.92GB  1:38   link 1Gbps
6305   VBS.copy  Winpe32               Wim      7.92    1:21   link 1Gbps
6305   robocopy  Winpe32               Wim      7.92    1:17   link 1Gbps

If you don't have robocopy.exe available, why not run it from the network share you are copying your files from? In my case, I prefer to do that so I don't have to rebuild my WinPE boot.wim file every time I want to make a change and then update dozens of flash drives.

NullInjectorError: No provider for AngularFirestore

Adding AngularFirestoreModule.enablePersistence() in import section resolved my issue:

imports: [
    BrowserModule, AngularFireModule, 
    AngularFireModule.initializeApp(config),
    AngularFirestoreModule.enablePersistence()
]

Why is there an unexplainable gap between these inline-block div elements?

simply add a border: 2px solid #e60000; to your 2nd div tag CSS.

Definitely it works

#Div2Id {
    border: 2px solid #e60000; --> color is your preference
}

How to enable C++11 in Qt Creator?

As an alternative for handling both cases addressed in Ali's excellent answer, I usually add

# With C++11 support
greaterThan(QT_MAJOR_VERSION, 4){    
CONFIG += c++11
} else {
QMAKE_CXXFLAGS += -std=c++0x
}

to my project files. This can be handy when you don't really care much about which Qt version is people using in your team, but you want them to have C++11 enabled in any case.

Change working directory in my current shell context when running Node script

There is no built-in method for Node to change the CWD of the underlying shell running the Node process.

You can change the current working directory of the Node process through the command process.chdir().

var process = require('process');
process.chdir('../');

When the Node process exists, you will find yourself back in the CWD you started the process in.

How to import Swagger APIs into Postman?

I work on PHP and have used Swagger 2.0 to document the APIs. The Swagger Document is created on the fly (at least that is what I use in PHP). The document is generated in the JSON format.

Sample document

{
    "swagger": "2.0",
    "info": {
    "title": "Company Admin Panel",
        "description": "Converting the Magento code into core PHP and RESTful APIs for increasing the performance of the website.",
        "contact": {
        "email": "[email protected]"
        },
        "version": "1.0.0"
    },
    "host": "localhost/cv_admin/api",
    "schemes": [
    "http"
],
    "paths": {
    "/getCustomerByEmail.php": {
        "post": {
            "summary": "List the details of customer by the email.",
                "consumes": [
                "string",
                "application/json",
                "application/x-www-form-urlencoded"
            ],
                "produces": [
                "application/json"
            ],
                "parameters": [
                    {
                        "name": "email",
                        "in": "body",
                        "description": "Customer email to ge the data",
                        "required": true,
                        "schema": {
                        "properties": {
                            "id": {
                                "properties": {
                                    "abc": {
                                        "properties": {
                                            "inner_abc": {
                                                "type": "number",
                                                    "default": 1,
                                                    "example": 123
                                                }
                                            },
                                            "type": "object"
                                        },
                                        "xyz": {
                                        "type": "string",
                                            "default": "xyz default value",
                                            "example": "xyz example value"
                                        }
                                    },
                                    "type": "object"
                                }
                            }
                        }
                    }
                ],
                "responses": {
                "200": {
                    "description": "Details of the customer"
                    },
                    "400": {
                    "description": "Email required"
                    },
                    "404": {
                    "description": "Customer does not exist"
                    },
                    "default": {
                    "description": "an \"unexpected\" error"
                    }
                }
            }
        },
        "/getCustomerById.php": {
        "get": {
            "summary": "List the details of customer by the ID",
                "parameters": [
                    {
                        "name": "id",
                        "in": "query",
                        "description": "Customer ID to get the data",
                        "required": true,
                        "type": "integer"
                    }
                ],
                "responses": {
                "200": {
                    "description": "Details of the customer"
                    },
                    "400": {
                    "description": "ID required"
                    },
                    "404": {
                    "description": "Customer does not exist"
                    },
                    "default": {
                    "description": "an \"unexpected\" error"
                    }
                }
            }
        },
        "/getShipmentById.php": {
        "get": {
            "summary": "List the details of shipment by the ID",
                "parameters": [
                    {
                        "name": "id",
                        "in": "query",
                        "description": "Shipment ID to get the data",
                        "required": true,
                        "type": "integer"
                    }
                ],
                "responses": {
                "200": {
                    "description": "Details of the shipment"
                    },
                    "404": {
                    "description": "Shipment does not exist"
                    },
                    "400": {
                    "description": "ID required"
                    },
                    "default": {
                    "description": "an \"unexpected\" error"
                    }
                }
            }
        }
    },
    "definitions": {

    }
}

This can be imported into Postman as follow.

  1. Click on the 'Import' button in the top left corner of Postman UI.
  2. You will see multiple options to import the API doc. Click on the 'Paste Raw Text'.
  3. Paste the JSON format in the text area and click import.
  4. You will see all your APIs as 'Postman Collection' and can use it from the Postman.

Importing the JSON into Postman

Imported APIs

You can also use 'Import From Link'. Here paste the URL which generates the JSON format of the APIs from the Swagger or any other API Document tool.

This is my Document (JSON) generation file. It's in PHP. I have no idea of JAVA along with Swagger.

<?php
require("vendor/autoload.php");
$swagger = \Swagger\scan('path_of_the_directory_to_scan');
header('Content-Type: application/json');
echo $swagger;

How to strip all non-alphabetic characters from string in SQL Server?

I just found this built into Oracle 10g if that is what you're using. I had to strip all the special characters out for a phone number compare.

regexp_replace(c.phone, '[^0-9]', '')

ReactJS: "Uncaught SyntaxError: Unexpected token <"

Add type="text/babel" as an attribute of the script tag, like this:

<script type="text/babel" src="./lander.js"></script>

SQLSTATE[HY000] [2002] Connection refused within Laravel homestead

I could be because you might have not restarted PHP artisan since long

So After making DB changes and config:clear Tinker works fine

But to make browser refect the new DB connection you need to re-run

php artisan serve

Recursively find files with a specific extension

Using find's -regex argument:

find . -regex '.*/Robert\.\(h\|cpp\)$'

Or just using -name:

find . -name 'Robert.*' -a \( -name '*.cpp' -o -name '*.h' \)

How to access POST form fields

app.use(express.bodyParser());

Then for app.post request you can get post values via req.body.{post request variable}.

.ssh directory not being created

I am assuming that you have enough permissions to create this directory.

To fix your problem, you can either ssh to some other location:

ssh [email protected]

and accept new key - it will create directory ~/.ssh and known_hosts underneath, or simply create it manually using

mkdir ~/.ssh
chmod 700 ~/.ssh

Note that chmod 700 is an important step!

After that, ssh-keygen should work without complaints.

change values in array when doing foreach

With the Array object methods you can modify the Array content yet compared to the basic for loops, these methods lack one important functionality. You can not modify the index on the run.

For example if you will remove the current element and place it to another index position within the same array you can easily do this. If you move the current element to a previous position there is no problem in the next iteration you will get the same next item as if you hadn't done anything.

Consider this code where we move the item at index position 5 to index position 2 once the index counts up to 5.

var ar = [0,1,2,3,4,5,6,7,8,9];
ar.forEach((e,i,a) => {
i == 5 && a.splice(2,0,a.splice(i,1)[0])
console.log(i,e);
}); // 0 0 - 1 1 - 2 2 - 3 3 - 4 4 - 5 5 - 6 6 - 7 7 - 8 8 - 9 9

However if we move the current element to somewhere beyond the current index position things get a little messy. Then the very next item will shift into the moved items position and in the next iteration we will not be able to see or evaluate it.

Consider this code where we move the item at index position 5 to index position 7 once the index counts up to 5.

var a = [0,1,2,3,4,5,6,7,8,9];
a.forEach((e,i,a) => {
i == 5 && a.splice(7,0,a.splice(i,1)[0])
console.log(i,e);
}); // 0 0 - 1 1 - 2 2 - 3 3 - 4 4 - 5 5 - 6 7 - 7 5 - 8 8 - 9 9

So we have never met 6 in the loop. Normally in a for loop you are expected decrement the index value when you move the array item forward so that your index stays at the same position in the next run and you can still evaluate the item shifted into the removed item's place. This is not possible with array methods. You can not alter the index. Check the following code

var a = [0,1,2,3,4,5,6,7,8,9];
a.forEach((e,i,a) => {
i == 5 && (a.splice(7,0,a.splice(i,1)[0]), i--);
console.log(i,e);
}); // 0 0 - 1 1 - 2 2 - 3 3 - 4 4 - 4 5 - 6 7 - 7 5 - 8 8 - 9 9

As you see when we decrement i it will not continue from 5 but 6, from where it was left.

So keep this in mind.

Using setImageDrawable dynamically to set image in an ImageView

imageView.setImageDrawable(getResources().getDrawable(R.drawable.my_drawable));

Bogus foreign key constraint fail

On demand, now as an answer...

When using MySQL Query Browser or phpMyAdmin, it appears that a new connection is opened for each query (bugs.mysql.com/bug.php?id=8280), making it neccessary to write all the drop statements in one query, eg.

SET FOREIGN_KEY_CHECKS=0; 
DROP TABLE my_first_table_to_drop; 
DROP TABLE my_second_table_to_drop; 
SET FOREIGN_KEY_CHECKS=1; 

Where the SET FOREIGN_KEY_CHECKS=1 serves as an extra security measure...

How to run Java program in command prompt

All you need to do is:

  • Build the mainjava class using the class path if any (optional)

    javac *.java [ -cp "wb.jar;"]

  • Create Manifest.txt file with content is:

    Main-Class: mainjava

  • Package the jar file for mainjava class

    jar cfm mainjava.jar Manifest.txt *.class

Then you can run this .jar file from cmd with class path (optional) and put arguments for it.

java [-cp "wb.jar;"] mainjava arg0 arg1 

HTH.

A transport-level error has occurred when receiving results from the server

Try the following command on the command prompt:

netsh interface tcp set global autotuning=disabled

This turns off the auto scaling abilities of the network stack

How to create a file name with the current date & time in Python?

now is a class method in the class datetime in the module datetime. So you need

datetime.datetime.now()

Or you can use a different import

from datetime import datetime

Done this way allows you to use datetime.now as per the code in the question.

How can I know when an EditText loses focus?

Using Java 8 lambda expression:

editText.setOnFocusChangeListener((v, hasFocus) -> {
    if(!hasFocus) {
        String value = String.valueOf( editText.getText() );
    }        
});

Read next word in java

You already get the next line in this line of your code:

 String line = sc.nextLine();  

To get the words of a line, I would recommend to use:

String[] words = line.split(" ");

How do I find the location of my Python site-packages directory?

An additional note to the get_python_lib function mentioned already: on some platforms different directories are used for platform specific modules (eg: modules that require compilation). If you pass plat_specific=True to the function you get the site packages for platform specific packages.

Visual Studio 2015 doesn't have cl.exe

In Visual Studio 2019 you can find cl.exe inside

32-BIT : C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\bin\Hostx86\x86
64-BIT : C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.20.27508\bin\Hostx64\x64

Before trying to compile either run vcvars32 for 32-Bit compilation or vcvars64 for 64-Bit.

32-BIT : "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars32.bat"
64-BIT : "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"

If you can't find the file or the directory, try going to C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC and see if you can find a folder with a version number. If you can't, then you probably haven't installed C++ through the Visual Studio Installation yet.

Android Studio is slow (how to speed up)?

My Android Studio was not only slow in general use, but also when building.

Here's what I did:

  1. Uninstalled Android Studio (Don't delete, uninstall it and check delete the SDK too). Then delete Android folders located in C:\Users\\ folder namely: .android, AndroidStudioX.X
  2. Uninstall the SDKs via the SDK manager, remove everything ( If there is lef SDK folder, delete them )
  3. Download and Reinstall the latest build for Android Studio (v2.1.2 as of this writing); Install only the SDK/Emulators you need;

It's fast now.


My Story before that:

My laptop sports an Intel Core i7-3612QM and 8gig of ram. When I builded, all the 4 cores/8 threads were on 100% usage. My entire system froze until the ~10 minute wass done. Gradle took me like ~10 unproductive minutes of slow down. This is very annoying. I am using Android Studio since 1.4. There were also tremendous slow down when I copy paste code to and from, selecting menus, right-click context menus, editing manifest, editing gradle files, opening layout files, rendering in the UI Editor, etc. Its was very unusable most of the time.

Due to frustration, I did the above steps. Its fast now. Very usable just as before. I build for only ~20 seconds compare to ~10minutes before that. Also, Android Studio eats about 6gig with emulator and browser with lots of tab open, unlike before its hovering on 98% RAM usage. Not just that, I even saved 45 gigs of space for whatever reason. I only use couple of SDKs and Emulators when I checked the Android SDK folder, it occupies 45gig of space! I think the IDE is having a hard time accessing/IO on my SDK folder.

If you've tried other given solutions and still experiencing the same issue, it may be time to remove Android IDE/SDKs altogether and start anew (it might take you sometime to setup that newly, but its worth it. Considering I've been suffering this sluggishness for months and cost me my productivity).

I really guess that this might be caused by cumulative patches that has been done since then. Or the 45 gig SDK folder on my poorly defragmented drive. I don't know and I could be wrong.

Thank you! HTH

How to keep indent for second line in ordered lists via CSS?

my solution is quite the same as Pumbaa80's one, but I suggest to use display: table instead of display:table-row for li element. So it will be something like this:

ol {
    counter-reset: foo; /* default display:list-item */
}

ol > li {
    counter-increment: foo;
    display: table; /* instead of table-row */
}

ol > li::before {
    content: counter(foo) ".";
    display: table-cell;
    text-align: right;
}

So now we can use margins for spacing between li's

JSON ValueError: Expecting property name: line 1 column 2 (char 1)

All other answers may answer your query, but I faced same issue which was due to stray , which I added at the end of my json string like this:

{
 "key":"123sdf",
 "bus_number":"asd234sdf",
}

I finally got it working when I removed extra , like this:

{
 "key":"123sdf",
 "bus_number":"asd234sdf"
}

Hope this help! cheers.

How many bytes is unsigned long long?

It must be at least 64 bits. Other than that it's implementation defined.

Strictly speaking, unsigned long long isn't standard in C++ until the C++0x standard. unsigned long long is a 'simple-type-specifier' for the type unsigned long long int (so they're synonyms).

The long long set of types is also in C99 and was a common extension to C++ compilers even before being standardized.

How do we check if a pointer is NULL pointer?

The compiler must provide a consistent type system, and provide a set of standard conversions. Neither the integer value 0 nor the NULL pointer need to be represented by all-zero bits, but the compiler must take care of converting the "0" token in the input file to the correct representation for integer zero, and the cast to pointer type must convert from integer to pointer representation.

The implication of this is that

void *p;
memset(&p, 0, sizeof p);
if(p) { ... }

is not guaranteed to behave the same on all target systems, as you are making an assumption about the bit pattern here.

As an example, I have an embedded platform that has no memory protection, and keeps the interrupt vectors at address 0, so by convention, integers and pointers are XORed with 0x2000000 when converted, which leaves (void *)0 pointing at an address that generates a bus error when dereferenced, however testing the pointer with an if statement will return it to integer representation first, which is then all-zeros.

Check if a value is in an array (C#)

Not very clear what your issue is, but it sounds like you want something like this:

    List<string> printer = new List<string>( new [] { "jupiter", "neptune", "pangea", "mercury", "sonic" } );

    if( printer.Exists( p => p.Equals( "jupiter" ) ) )
    {
        ...
    }

Get a DataTable Columns DataType

You can get column type of DataTable with DataType attribute of datatable column like below:

var type = dt.Columns[0].DataType

dt : DataTable object.

0 : DataTable column index.

Hope It Helps

Ty :)

How to simulate POST request?

Simple way is to use curl from command-line, for example:

DATA="foo=bar&baz=qux"
curl --data "$DATA" --request POST --header "Content-Type:application/x-www-form-urlencoded" http://example.com/api/callback | python -m json.tool

or here is example how to send raw POST request using Bash shell (JSON request):

exec 3<> /dev/tcp/example.com/80

DATA='{"email": "[email protected]"}'
LEN=$(printf "$DATA" | wc -c)

cat >&3 << EOF
POST /api/retrieveInfo HTTP/1.1
Host: example.com
User-Agent: Bash
Accept: */*
Content-Type:application/json
Content-Length: $LEN
Connection: close

$DATA
EOF

# Read response.
while read line <&3; do
   echo $line
done

Convert string to datetime in vb.net

Pass the decode pattern to ParseExact

Dim d as string = "201210120956"
Dim dt = DateTime.ParseExact(d, "yyyyMMddhhmm", Nothing)

ParseExact is available only from Net FrameWork 2.0.
If you are still on 1.1 you could use Parse, but you need to provide the IFormatProvider adequate to your string

How to use ArgumentCaptor for stubbing?

The line

when(someObject.doSomething(argumentCaptor.capture())).thenReturn(true);

would do the same as

when(someObject.doSomething(Matchers.any())).thenReturn(true);

So, using argumentCaptor.capture() when stubbing has no added value. Using Matchers.any() shows better what really happens and therefor is better for readability. With argumentCaptor.capture(), you can't read what arguments are really matched. And instead of using any(), you can use more specific matchers when you have more information (class of the expected argument), to improve your test.

And another problem: If using argumentCaptor.capture() when stubbing it becomes unclear how many values you should expect to be captured after verification. We want to capture a value during verification, not during stubbing because at that point there is no value to capture yet. So what does the argument captors capture method capture during stubbing? It capture anything because there is nothing to be captured yet. I consider it to be undefined behavior and I don't want to use undefined behavior.

Open Windows Explorer and select a file

Check out this snippet:

Private Sub openDialog()
    Dim fd As Office.FileDialog

    Set fd = Application.FileDialog(msoFileDialogFilePicker)

   With fd

      .AllowMultiSelect = False

      ' Set the title of the dialog box.
      .Title = "Please select the file."

      ' Clear out the current filters, and add our own.
      .Filters.Clear
      .Filters.Add "Excel 2003", "*.xls"
      .Filters.Add "All Files", "*.*"

      ' Show the dialog box. If the .Show method returns True, the
      ' user picked at least one file. If the .Show method returns
      ' False, the user clicked Cancel.
      If .Show = True Then
        txtFileName = .SelectedItems(1) 'replace txtFileName with your textbox

      End If
   End With
End Sub

I think this is what you are asking for.

Targeting both 32bit and 64bit with Visual Studio in same solution/project

If you use Custom Actions written in .NET as part of your MSI installer then you have another problem.

The 'shim' that runs these custom actions is always 32bit then your custom action will run 32bit as well, despite what target you specify.

More info & some ninja moves to get around (basically change the MSI to use the 64 bit version of this shim)

Building an MSI in Visual Studio 2005/2008 to work on a SharePoint 64

64-bit Managed Custom Actions with Visual Studio

What is a CSRF token? What is its importance and how does it work?

The site generates a unique token when it makes the form page. This token is required to post/get data back to the server.

Since the token is generated by your site and provided only when the page with the form is generated, some other site can't mimic your forms -- they won't have the token and therefore can't post to your site.

app.config for a class library

You generally should not add an app.config file to a class library project; it won't be used without some painful bending and twisting on your part. It doesn't hurt the library project at all - it just won't do anything at all.

Instead, you configure the application which is using your library; so the configuration information required would go there. Each application that might use your library likely will have different requirements, so this actually makes logical sense, too.

PHP & localStorage;

localStorage is something that is kept on the client side. There is no data transmitted to the server side.

You can only get the data with JavaScript and you can send it to the server side with Ajax.

How to use HttpWebRequest (.NET) asynchronously?

Everyone so far has been wrong, because BeginGetResponse() does some work on the current thread. From the documentation:

The BeginGetResponse method requires some synchronous setup tasks to complete (DNS resolution, proxy detection, and TCP socket connection, for example) before this method becomes asynchronous. As a result, this method should never be called on a user interface (UI) thread because it might take considerable time (up to several minutes depending on network settings) to complete the initial synchronous setup tasks before an exception for an error is thrown or the method succeeds.

So to do this right:

void DoWithResponse(HttpWebRequest request, Action<HttpWebResponse> responseAction)
{
    Action wrapperAction = () =>
    {
        request.BeginGetResponse(new AsyncCallback((iar) =>
        {
            var response = (HttpWebResponse)((HttpWebRequest)iar.AsyncState).EndGetResponse(iar);
            responseAction(response);
        }), request);
    };
    wrapperAction.BeginInvoke(new AsyncCallback((iar) =>
    {
        var action = (Action)iar.AsyncState;
        action.EndInvoke(iar);
    }), wrapperAction);
}

You can then do what you need to with the response. For example:

HttpWebRequest request;
// init your request...then:
DoWithResponse(request, (response) => {
    var body = new StreamReader(response.GetResponseStream()).ReadToEnd();
    Console.Write(body);
});

Is object empty?

here's a good way to do it

function isEmpty(obj) {
  if (Array.isArray(obj)) {
    return obj.length === 0;
  } else if (typeof obj === 'object') {
    for (var i in obj) {
      return false;
    }
    return true;
  } else {
    return !obj;
  }
}

Escape sequence \f - form feed - what exactly is it?

Although recently its use is undefined, a common and useful use for the form feed is to separate sections of code vertically, like so: enter image description here (from http://ergoemacs.org/emacs/emacs_form_feed_section_paging.html)

How to change language settings in R

If you want to change R's language in terminal to English forever, this works fine for me in macOS:

Open terminal.app, and say:

touch .bash_profile

Then say:

open -a TextEdit.app .bash_profile

These two commands will help you open ".bash_profile" file in TextEdit.

Add this to ".bash_profile" file:

export LANG=en_US.UTF-8

Then save the file, reopen terminal and type R, you will find it's language has changed to english.

If you want language come back to it's original, just simply add a # before export LANG=en_US.UTF-8.

Checking version of angular-cli that's installed?

You can find using CLI ng --version

As I am using

angular-cli: 1.0.0-beta.28.3

node: 6.10.1

os: darwin x64

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Adding a Method to an Existing Object Instance

Consolidating Jason Pratt's and the community wiki answers, with a look at the results of different methods of binding:

Especially note how adding the binding function as a class method works, but the referencing scope is incorrect.

#!/usr/bin/python -u
import types
import inspect

## dynamically adding methods to a unique instance of a class


# get a list of a class's method type attributes
def listattr(c):
    for m in [(n, v) for n, v in inspect.getmembers(c, inspect.ismethod) if isinstance(v,types.MethodType)]:
        print m[0], m[1]

# externally bind a function as a method of an instance of a class
def ADDMETHOD(c, method, name):
    c.__dict__[name] = types.MethodType(method, c)

class C():
    r = 10 # class attribute variable to test bound scope

    def __init__(self):
        pass

    #internally bind a function as a method of self's class -- note that this one has issues!
    def addmethod(self, method, name):
        self.__dict__[name] = types.MethodType( method, self.__class__ )

    # predfined function to compare with
    def f0(self, x):
        print 'f0\tx = %d\tr = %d' % ( x, self.r)

a = C() # created before modified instnace
b = C() # modified instnace


def f1(self, x): # bind internally
    print 'f1\tx = %d\tr = %d' % ( x, self.r )
def f2( self, x): # add to class instance's .__dict__ as method type
    print 'f2\tx = %d\tr = %d' % ( x, self.r )
def f3( self, x): # assign to class as method type
    print 'f3\tx = %d\tr = %d' % ( x, self.r )
def f4( self, x): # add to class instance's .__dict__ using a general function
    print 'f4\tx = %d\tr = %d' % ( x, self.r )


b.addmethod(f1, 'f1')
b.__dict__['f2'] = types.MethodType( f2, b)
b.f3 = types.MethodType( f3, b)
ADDMETHOD(b, f4, 'f4')


b.f0(0) # OUT: f0   x = 0   r = 10
b.f1(1) # OUT: f1   x = 1   r = 10
b.f2(2) # OUT: f2   x = 2   r = 10
b.f3(3) # OUT: f3   x = 3   r = 10
b.f4(4) # OUT: f4   x = 4   r = 10


k = 2
print 'changing b.r from {0} to {1}'.format(b.r, k)
b.r = k
print 'new b.r = {0}'.format(b.r)

b.f0(0) # OUT: f0   x = 0   r = 2
b.f1(1) # OUT: f1   x = 1   r = 10  !!!!!!!!!
b.f2(2) # OUT: f2   x = 2   r = 2
b.f3(3) # OUT: f3   x = 3   r = 2
b.f4(4) # OUT: f4   x = 4   r = 2

c = C() # created after modifying instance

# let's have a look at each instance's method type attributes
print '\nattributes of a:'
listattr(a)
# OUT:
# attributes of a:
# __init__ <bound method C.__init__ of <__main__.C instance at 0x000000000230FD88>>
# addmethod <bound method C.addmethod of <__main__.C instance at 0x000000000230FD88>>
# f0 <bound method C.f0 of <__main__.C instance at 0x000000000230FD88>>

print '\nattributes of b:'
listattr(b)
# OUT:
# attributes of b:
# __init__ <bound method C.__init__ of <__main__.C instance at 0x000000000230FE08>>
# addmethod <bound method C.addmethod of <__main__.C instance at 0x000000000230FE08>>
# f0 <bound method C.f0 of <__main__.C instance at 0x000000000230FE08>>
# f1 <bound method ?.f1 of <class __main__.C at 0x000000000237AB28>>
# f2 <bound method ?.f2 of <__main__.C instance at 0x000000000230FE08>>
# f3 <bound method ?.f3 of <__main__.C instance at 0x000000000230FE08>>
# f4 <bound method ?.f4 of <__main__.C instance at 0x000000000230FE08>>

print '\nattributes of c:'
listattr(c)
# OUT:
# attributes of c:
# __init__ <bound method C.__init__ of <__main__.C instance at 0x0000000002313108>>
# addmethod <bound method C.addmethod of <__main__.C instance at 0x0000000002313108>>
# f0 <bound method C.f0 of <__main__.C instance at 0x0000000002313108>>

Personally, I prefer the external ADDMETHOD function route, as it allows me to dynamically assign new method names within an iterator as well.

def y(self, x):
    pass
d = C()
for i in range(1,5):
    ADDMETHOD(d, y, 'f%d' % i)
print '\nattributes of d:'
listattr(d)
# OUT:
# attributes of d:
# __init__ <bound method C.__init__ of <__main__.C instance at 0x0000000002303508>>
# addmethod <bound method C.addmethod of <__main__.C instance at 0x0000000002303508>>
# f0 <bound method C.f0 of <__main__.C instance at 0x0000000002303508>>
# f1 <bound method ?.y of <__main__.C instance at 0x0000000002303508>>
# f2 <bound method ?.y of <__main__.C instance at 0x0000000002303508>>
# f3 <bound method ?.y of <__main__.C instance at 0x0000000002303508>>
# f4 <bound method ?.y of <__main__.C instance at 0x0000000002303508>>

CSS :selected pseudo class similar to :checked, but for <select> elements

the :checked pseudo-class initially applies to such elements that have the HTML4 selected and checked attributes

Source: w3.org


So, this CSS works, although styling the color is not possible in every browser:

option:checked { color: red; }

An example of this in action, hiding the currently selected item from the drop down list.

_x000D_
_x000D_
option:checked { display:none; }
_x000D_
<select>_x000D_
    <option>A</option>_x000D_
    <option>B</option>_x000D_
    <option>C</option>_x000D_
</select>
_x000D_
_x000D_
_x000D_


To style the currently selected option in the closed dropdown as well, you could try reversing the logic:

select { color: red; }
option:not(:checked) { color: black; } /* or whatever your default style is */

Wait 5 seconds before executing next line

You can add delay by making small changes to your function ( async and await ).

const addNSecondsDelay = (n) => {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve();
    }, n * 1000);
  });
}

const asyncFunctionCall = async () {

  console.log("stpe-1"); 
  await addNSecondsDelay(5);
  console.log("step-2 after 5 seconds delay"); 

}

asyncFunctionCall();

Google MAP API v3: Center & Zoom on displayed markers

for center and auto zoom on display markers

// map: an instance of google.maps.Map object

// latlng_points_array: an array of google.maps.LatLng objects

var latlngbounds = new google.maps.LatLngBounds( );

    for ( var i = 0; i < latlng_points_array.length; i++ ) {
        latlngbounds.extend( latlng_points_array[i] );
    }

map.fitBounds( latlngbounds );