Programs & Examples On #Visual assist

Visual Assist is a commercial Visual Studio extension that enhances overall code editing.

CSS selectors ul li a {...} vs ul > li > a {...}

ul>li selects all li that are a direct child of ul whereas ul li selects all li that are anywhere within (descending as deep as you like) a ul

For HTML:

<ul>
  <li><span><a href='#'>Something</a></span></li>
  <li><a href='#'>or Other</a></li>
</ul>

And CSS:

li a{ color: green; }
li>a{ color: red; }

The colour of Something will remain green but or Other will be red

Part 2, you should write the rule to be appropriate to the situation, I think the speed difference would be incredibly small, and probably overshadowed by the extra characters involved in writing more code, and definitely overshadowed by the time taken by the developer to think about it.

However, as a rule of thumb, the more specific you are with your rules, the faster the CSS engines can locate the DOM elements you want to apply it to, so I expect li>a is faster than li a as the DOM search can be cut short earlier. It also means that nested anchors are not styled with that rule, is that what you want? <~~ much more pertinent question.

String "true" and "false" to boolean

ActiveRecord provides a clean way of doing this.

def is_true?(string)
  ActiveRecord::ConnectionAdapters::Column::TRUE_VALUES.include?(string)
end

ActiveRecord::ConnectionAdapters::Column::TRUE_VALUES has all of the obvious representations of True values as strings.

What is a race condition?

There is an important technical difference between race conditions and data races. Most answers seem to make the assumption that these terms are equivalent, but they are not.

A data race occurs when 2 instructions access the same memory location, at least one of these accesses is a write and there is no happens before ordering among these accesses. Now what constitutes a happens before ordering is subject to a lot of debate, but in general ulock-lock pairs on the same lock variable and wait-signal pairs on the same condition variable induce a happens-before order.

A race condition is a semantic error. It is a flaw that occurs in the timing or the ordering of events that leads to erroneous program behavior.

Many race conditions can be (and in fact are) caused by data races, but this is not necessary. As a matter of fact, data races and race conditions are neither the necessary, nor the sufficient condition for one another. This blog post also explains the difference very well, with a simple bank transaction example. Here is another simple example that explains the difference.

Now that we nailed down the terminology, let us try to answer the original question.

Given that race conditions are semantic bugs, there is no general way of detecting them. This is because there is no way of having an automated oracle that can distinguish correct vs. incorrect program behavior in the general case. Race detection is an undecidable problem.

On the other hand, data races have a precise definition that does not necessarily relate to correctness, and therefore one can detect them. There are many flavors of data race detectors (static/dynamic data race detection, lockset-based data race detection, happens-before based data race detection, hybrid data race detection). A state of the art dynamic data race detector is ThreadSanitizer which works very well in practice.

Handling data races in general requires some programming discipline to induce happens-before edges between accesses to shared data (either during development, or once they are detected using the above mentioned tools). this can be done through locks, condition variables, semaphores, etc. However, one can also employ different programming paradigms like message passing (instead of shared memory) that avoid data races by construction.

How to change menu item text dynamically in Android

you can do this create a global "Menu" object then assign it in onCreateOptionMenu

public class ExampleActivity extends AppCompatActivity
    Menu menu;

then assign here

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu, menu);
    this.menu = menu;
    return true;
}

Then later use assigned Menu object to get required items

menu.findItem(R.id.bedSwitch).setTitle("Your Text");

Maximum packet size for a TCP connection

The absolute limitation on TCP packet size is 64K (65535 bytes), but in practicality this is far larger than the size of any packet you will see, because the lower layers (e.g. ethernet) have lower packet sizes.

The MTU (Maximum Transmission Unit) for Ethernet, for instance, is 1500 bytes. Some types of networks (like Token Ring) have larger MTUs, and some types have smaller MTUs, but the values are fixed for each physical technology.

Jackson - How to process (deserialize) nested JSON?

Your data is problematic in that you have inner wrapper objects in your array. Presumably your Vendor object is designed to handle id, name, company_id, but each of those multiple objects are also wrapped in an object with a single property vendor.

I'm assuming that you're using the Jackson Data Binding model.

If so then there are two things to consider:

The first is using a special Jackson config property. Jackson - since 1.9 I believe, this may not be available if you're using an old version of Jackson - provides UNWRAP_ROOT_VALUE. It's designed for cases where your results are wrapped in a top-level single-property object that you want to discard.

So, play around with:

objectMapper.configure(SerializationConfig.Feature.UNWRAP_ROOT_VALUE, true);

The second is using wrapper objects. Even after discarding the outer wrapper object you still have the problem of your Vendor objects being wrapped in a single-property object. Use a wrapper to get around this:

class VendorWrapper
{
    Vendor vendor;

    // gettors, settors for vendor if you need them
}

Similarly, instead of using UNWRAP_ROOT_VALUES, you could also define a wrapper class to handle the outer object. Assuming that you have correct Vendor, VendorWrapper object, you can define:

class VendorsWrapper
{
    List<VendorWrapper> vendors = new ArrayList<VendorWrapper>();

    // gettors, settors for vendors if you need them
}

// in your deserialization code:
ObjectMapper mapper = new ObjectMapper();
JsonNode rootNode = mapper.readValue(jsonInput, VendorsWrapper.class); 

The object tree for VendorsWrapper is analogous to your JSON:

VendorsWrapper:
    vendors:
    [
        VendorWrapper
            vendor: Vendor,
        VendorWrapper:
            vendor: Vendor,
        ...
    ]

Finally, you might use the Jackson Tree Model to parse this into JsonNodes, discarding the outer node, and for each JsonNode in the ArrayNode, calling:

mapper.readValue(node.get("vendor").getTextValue(), Vendor.class);

That might result in less code, but it seems no less clumsy than using two wrappers.

How to split a list by comma not space

Create a bash function

split_on_commas() {
  local IFS=,
  local WORD_LIST=($1)
  for word in "${WORD_LIST[@]}"; do
    echo "$word"
  done
}

split_on_commas "this,is a,list" | while read item; do
  # Custom logic goes here
  echo Item: ${item}
done

... this generates the following output:

Item: this
Item: is a
Item: list

(Note, this answer has been updated according to some feedback)

(change) vs (ngModelChange) in angular

(change) event bound to classical input change event.

https://developer.mozilla.org/en-US/docs/Web/Events/change

You can use (change) event even if you don't have a model at your input as

<input (change)="somethingChanged()">

(ngModelChange) is the @Output of ngModel directive. It fires when the model changes. You cannot use this event without ngModel directive.

https://github.com/angular/angular/blob/master/packages/forms/src/directives/ng_model.ts#L124

As you discover more in the source code, (ngModelChange) emits the new value.

https://github.com/angular/angular/blob/master/packages/forms/src/directives/ng_model.ts#L169

So it means you have ability of such usage:

<input (ngModelChange)="modelChanged($event)">
modelChanged(newObj) {
    // do something with new value
}

Basically, it seems like there is no big difference between two, but ngModel events gains the power when you use [ngValue].

  <select [(ngModel)]="data" (ngModelChange)="dataChanged($event)" name="data">
      <option *ngFor="let currentData of allData" [ngValue]="currentData">
          {{data.name}}
      </option>
  </select>
dataChanged(newObj) {
    // here comes the object as parameter
}

assume you try the same thing without "ngModel things"

<select (change)="changed($event)">
    <option *ngFor="let currentData of allData" [value]="currentData.id">
        {{data.name}}
    </option>
</select>
changed(e){
    // event comes as parameter, you'll have to find selectedData manually
    // by using e.target.data
}

How can I create a progress bar in Excel VBA?

Sub ShowProgress()
' Author    : Marecki
  Const x As Long = 150000
  Dim i&, PB$

  For i = 1 To x
    PB = Format(i / x, "00 %")
    Application.StatusBar = "Progress: " & PB & "  >>" & String(Val(PB), Chr(183)) & String(100 - Val(PB), Chr(32)) & "<<"
    Application.StatusBar = "Progress: " & PB & "  " & ChrW$(10111 - Val(PB) / 11)
    Application.StatusBar = "Progress: " & PB & "  " & String(100 - Val(PB), ChrW$(9608))
  Next i

  Application.StatusBar = ""
End SubShowProgress

How do I get class name in PHP?

This will return pure class name even when using namespace:

echo substr(strrchr(__CLASS__, "\\"), 1);    

How do I find which process is leaking memory?

I suggest the use of htop, as a better alternative to top.

What is unit testing and how do you do it?

What is unit testing?

Unit testing simply verifies that individual units of code (mostly functions) work as expected. Usually you write the test cases yourself, but some can be automatically generated.

The output from a test can be as simple as a console output, to a "green light" in a GUI such as NUnit, or a different language-specific framework.

Performing unit tests is designed to be simple, generally the tests are written in the form of functions that will determine whether a returned value equals the value you were expecting when you wrote the function (or the value you will expect when you eventually write it - this is called Test Driven Development when you write the tests first).

How do you perform unit tests?

Imagine a very simple function that you would like to test:

int CombineNumbers(int a, int b) {
    return a+b;
}

The unit test code would look something like this:

void TestCombineNumbers() {
    Assert.IsEqual(CombineNumbers(5, 10), 15); // Assert is an object that is part of your test framework
    Assert.IsEqual(CombineNumbers(1000, -100), 900);
}

When you run the tests, you will be informed that these tests have passed. Now that you've built and run the tests, you know that this particular function, or unit, will perform as you expect.

Now imagine another developer comes along and changes the CombineNumbers() function for performance, or some other reason:

int CombineNumbers(int a, int b) {
    return a * b;
}

When the developer runs the tests that you have created for this very simple function, they will see that the first Assert fails, and they now know that the build is broken.

When should you perform unit tests?

They should be done as often as possible. When you are performing tests as part of the development process, your code is automatically going to be designed better than if you just wrote the functions and then moved on. Also, concepts such as Dependency Injection are going to evolve naturally into your code.

The most obvious benefit is knowing down the road that when a change is made, no other individual units of code were affected by it if they all pass the tests.

How to access html form input from asp.net code behind

Simplest way IMO is to include an ID and runat server tag on all your elements.

<div id="MYDIV" runat="server" />

Since it sounds like these are dynamically inserted controls, you might appreciate FindControl().

How to extract or unpack an .ab file (Android Backup file)

As per https://android.stackexchange.com/a/78183/239063 you can run a one line command in Linux to add in an appropriate tar header to extract it.

( printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" ; tail -c +25 backup.ab ) | tar xfvz -

Replace backup.ab with the path to your file.

Where does Visual Studio look for C++ header files?

There seems to be a bug in Visual Studio 2015 community. For a 64-bit project, the include folder isn't found unless it's in the win32 bit configuration Additional Include Folders list.

Displaying the build date

Add below to pre-build event command line:

echo %date% %time% > "$(ProjectDir)\Resources\BuildDate.txt"

Add this file as resource, now you have 'BuildDate' string in your resources.

To create resources, see How to create and use resources in .NET.

How can I plot data with confidence intervals?

Here is part of my program related to plotting confidence interval.

1. Generate the test data

ads = 1
require(stats); require(graphics)
library(splines)
x_raw <- seq(1,10,0.1)
y <- cos(x_raw)+rnorm(len_data,0,0.1)
y[30] <- 1.4 # outlier point
len_data = length(x_raw)
N <- len_data
summary(fm1 <- lm(y~bs(x_raw, df=5), model = TRUE, x =T, y = T))
ht <-seq(1,10,length.out = len_data)
plot(x = x_raw, y = y,type = 'p')
y_e <- predict(fm1, data.frame(height = ht))
lines(x= ht, y = y_e)

Result

enter image description here

2. Fitting the raw data using B-spline smoother method

sigma_e <- sqrt(sum((y-y_e)^2)/N)
print(sigma_e)
H<-fm1$x
A <-solve(t(H) %*% H)
y_e_minus <- rep(0,N)
y_e_plus <- rep(0,N)
y_e_minus[N]
for (i in 1:N)
{
    tmp <-t(matrix(H[i,])) %*% A %*% matrix(H[i,])
    tmp <- 1.96*sqrt(tmp)
    y_e_minus[i] <- y_e[i] - tmp
    y_e_plus[i] <- y_e[i] + tmp
}
plot(x = x_raw, y = y,type = 'p')
polygon(c(ht,rev(ht)),c(y_e_minus,rev(y_e_plus)),col = rgb(1, 0, 0,0.5), border = NA)
#plot(x = x_raw, y = y,type = 'p')
lines(x= ht, y = y_e_plus, lty = 'dashed', col = 'red')
lines(x= ht, y = y_e)
lines(x= ht, y = y_e_minus, lty = 'dashed', col = 'red')

Result

enter image description here

Rails DateTime.now without Time

If you want today's date without the time, just use Date.today

Eclipse : Maven search dependencies doesn't work

Use https://search.maven.org/ manually with the prefix fc: to search for class names. Both Netbeans and Eclipse seem to be too stupid to use that search interface and the gigabytes of downloaded repository indexes seem to not contain any class information. Total waste of disk space. Those IDE projects are so badly maintained lately, I wish they would move development to GitHub.

How to define two fields "unique" as couple

There is a simple solution for you called unique_together which does exactly what you want.

For example:

class MyModel(models.Model):
  field1 = models.CharField(max_length=50)
  field2 = models.CharField(max_length=50)

  class Meta:
    unique_together = ('field1', 'field2',)

And in your case:

class Volume(models.Model):
  id = models.AutoField(primary_key=True)
  journal_id = models.ForeignKey(Journals, db_column='jid', null=True, verbose_name = "Journal")
  volume_number = models.CharField('Volume Number', max_length=100)
  comments = models.TextField('Comments', max_length=4000, blank=True)

  class Meta:
    unique_together = ('journal_id', 'volume_number',)

PHP shell_exec() vs exec()

A couple of distinctions that weren't touched on here:

  • With exec(), you can pass an optional param variable which will receive an array of output lines. In some cases this might save time, especially if the output of the commands is already tabular.

Compare:

exec('ls', $out);
var_dump($out);
// Look an array

$out = shell_exec('ls');
var_dump($out);
// Look -- a string with newlines in it

Conversely, if the output of the command is xml or json, then having each line as part of an array is not what you want, as you'll need to post-process the input into some other form, so in that case use shell_exec.

It's also worth pointing out that shell_exec is an alias for the backtic operator, for those used to *nix.

$out = `ls`;
var_dump($out);

exec also supports an additional parameter that will provide the return code from the executed command:

exec('ls', $out, $status);
if (0 === $status) {
    var_dump($out);
} else {
    echo "Command failed with status: $status";
}

As noted in the shell_exec manual page, when you actually require a return code from the command being executed, you have no choice but to use exec.

How do a LDAP search/authenticate against this LDAP in Java

try {
    LdapContext ctx = new InitialLdapContext(env, null);
    ctx.setRequestControls(null);
    NamingEnumeration<?> namingEnum = ctx.search("ou=people,dc=example,dc=com", "(objectclass=user)", getSimpleSearchControls());
    while (namingEnum.hasMore ()) {
        SearchResult result = (SearchResult) namingEnum.next ();    
        Attributes attrs = result.getAttributes ();
        System.out.println(attrs.get("cn"));

    } 
    namingEnum.close();
} catch (Exception e) {
    e.printStackTrace();
}

private SearchControls getSimpleSearchControls() {
    SearchControls searchControls = new SearchControls();
    searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);
    searchControls.setTimeLimit(30000);
    //String[] attrIDs = {"objectGUID"};
    //searchControls.setReturningAttributes(attrIDs);
    return searchControls;
}

Insert variable values in the middle of a string

You can use string.Format:

string template = "Hi We have these flights for you: {0}. Which one do you want";
string data = "A, B, C, D";
string message = string.Format(template, data);

You should load template from your resource file and data is your runtime values.

Be careful if you're translating to multiple languages, though: in some cases, you'll need different tokens (the {0}) in different languages.

What is the purpose of shuffling and sorting phase in the reducer in Map Reduce Programming?

I thought of just adding some points missing in above answers. This diagram taken from here clearly states the what's really going on.

enter image description here

If I state again the real purpose of

  • Split: Improves the parallel processing by distributing the processing load across different nodes (Mappers), which would save the overall processing time.

  • Combine: Shrinks the output of each Mapper. It would save the time spending for moving the data from one node to another.

  • Sort (Shuffle & Sort): Makes it easy for the run-time to schedule (spawn/start) new reducers, where while going through the sorted item list, whenever the current key is different from the previous, it can spawn a new reducer.

ALTER COLUMN in sqlite

There's no ALTER COLUMN in sqlite.

I believe your only option is to:

  • Rename the table to a temporary name
  • Create a new table without the NOT NULL constraint
  • Copy the content of the old table to the new one
  • Remove the old table

This other Stackoverflow answer explains the process in details

Add back button to action bar

Use this to show back button and move to previous activity,

final ActionBar actionBar = getSupportActionBar();
        assert actionBar != null;
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setHomeAsUpIndicator(R.drawable.back_dark);


@Override
    public boolean onOptionsItemSelected(final MenuItem item) {

        switch (item.getItemId()) {
            case android.R.id.home:
                onBackPressed();
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

Why is it said that "HTTP is a stateless protocol"?

HTTP is called as a stateless protocol because each request is executed independently, without any knowledge of the requests that were executed before it, which means once the transaction ends the connection between the browser and the server is also lost.

What makes the protocol stateless is that in its original design, HTTP is a relatively simple file transfer protocol:

  1. make a request for a file named by a URL,
  2. get the file in response,
  3. disconnect.

There was no relationship maintained between one connection and another, even from the same client. This simplifies the contract between client and server, and in many cases minimizes the amount of data that needs to be transferred.

The request was aborted: Could not create SSL/TLS secure channel

I had cert in store and on file. I tried to connect with file and got this error message. When I used the one in the store it worked. My best guess is that some sort of conflict arose as a result of the cert being in store when I wanted to use the one on file. (A different service on the same machine used the cert in store and I had developed a different service using the cert on file. Worked like a charm on dev until test).

How to set a timer in android

Here we go.. We will need two classes. I am posting a code which changes mobile audio profile after each 5 seconds (5000 mili seconds) ...

Our 1st Class

public class ChangeProfileActivityMain extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        Timer timer = new Timer();
        TimerTask updateProfile = new CustomTimerTask(ChangeProfileActivityMain.this);
        timer.scheduleAtFixedRate(updateProfile, 0, 5000);
    }

}

Our 2nd Class

public class CustomTimerTask extends TimerTask {

    private AudioManager audioManager;
    private Context context;
    private Handler mHandler = new Handler();

    // Write Custom Constructor to pass Context
    public CustomTimerTask(Context con) {
        this.context = con;
    }

    @Override
    public void run() {
        // TODO Auto-generated method stub

        // your code starts here.
        // I have used Thread and Handler as we can not show Toast without starting new thread when we are inside a thread.
        // As TimePicker has run() thread running., So We must show Toast through Handler.post in a new Thread. Thats how it works in Android..
        new Thread(new Runnable() {
            @Override
            public void run() {
                audioManager = (AudioManager) context.getApplicationContext().getSystemService(Context.AUDIO_SERVICE);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        if(audioManager.getRingerMode() == AudioManager.RINGER_MODE_SILENT) {
                            audioManager.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
                            Toast.makeText(context, "Ringer Mode set to Normal", Toast.LENGTH_SHORT).show();
                        } else {
                            audioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
                            Toast.makeText(context, "Ringer Mode set to Silent", Toast.LENGTH_SHORT).show();
                        }
                    }
                });
            }
        }).start();

    }

}

Loading custom configuration files

The config file is just an XML file, you can open it by:

private static XmlDocument loadConfigDocument()
{
    XmlDocument doc = null;
    try
    {
        doc = new XmlDocument();
        doc.Load(getConfigFilePath());
        return doc;
    }
    catch (System.IO.FileNotFoundException e)
    {
        throw new Exception("No configuration file found.", e);
    }
    catch (Exception ex)
    {
        return null;
    }
}

and later retrieving values by:

    // retrieve appSettings node

    XmlNode node =  doc.SelectSingleNode("//appSettings");

How to determine MIME type of file in android?

The above solution returned null in case of .rar file, using URLConnection.guessContentTypeFromName(url) worked in this case.

How to check if a given directory exists in Ruby

If it matters whether the file you're looking for is a directory and not just a file, you could use File.directory? or Dir.exist?. This will return true only if the file exists and is a directory.

As an aside, a more idiomatic way to write the method would be to take advantage of the fact that Ruby automatically returns the result of the last expression inside the method. Thus, you could write it like this:

def directory_exists?(directory)
  File.directory?(directory)
end

Note that using a method is not necessary in the present case.

How to prevent IFRAME from redirecting top-level window

Since the page you load inside the iframe can execute the "break out" code with a setInterval, onbeforeunload might not be that practical, since it could flud the user with 'Are you sure you want to leave?' dialogs.

There is also the iframe security attribute which only works on IE & Opera

:(

'heroku' does not appear to be a git repository

First, make sure you're logged into heroku:

heroku login 

Enter your credentials.

It's common to get this error when using a cloned git repo onto a new machine. Even if your heroku credentials are already on the machine, there is no link between the cloned repo and heroku locally yet. To do this, cd into the root dir of the cloned repo and run

heroku git:remote -a yourapp

PHP: Inserting Values from the Form into MySQL

Try this:

dbConfig.php

<?php
$mysqli = new mysqli('localhost', 'root', 'pwd', 'yr db name');
    if($mysqli->connect_error)
        {
        echo $mysqli->connect_error;
        }
    ?>

Index.php

<html>
<head><title>Inserting data in database table </title>
</head>
<body>
<form action="control_table.php" method="post">
<table border="1" background="red" align="center">
<tr>
<td>Login Name</td>
<td><input type="text" name="txtname" /></td>
</tr>
<br>
<tr>
<td>Password</td>
<td><input type="text" name="txtpwd" /></td>
</tr>
<tr>
<td>&nbsp;</td>
<td><input type="submit" name="txtbutton" value="SUBMIT" /></td>
</tr>
</table>
control_table.php
<?php include 'config.php'; ?>
<?php
$name=$pwd="";
    if(isset($_POST['txtbutton']))
        {
            $name = $_POST['txtname'];
            $pwd = $_POST['txtpwd'];
            $mysqli->query("insert into users(name,pwd) values('$name', '$pwd')");
        if(!$mysqli) 
        { echo mysqli_error(); }
    else
    {
        echo "Successfully Inserted <br />";
        echo "<a href='show.php'>View Result</a>";
    }

         }  

    ?>

CSS: center element within a <div> element

Create a new div element for your element to center, then add a class specifically for centering that element like this

<div id="myNewElement">
    <div class="centered">
        <input type="button" value="My Centered Button"/>
    </div>
</div>

Css

.centered{
    text-align:center;
}

How to override the [] operator in Python?

You are looking for the __getitem__ method. See http://docs.python.org/reference/datamodel.html, section 3.4.6

Setting up foreign keys in phpMyAdmin?

phpMyAdmin lets you define foreign keys using their "relations" view. But since, MySQL only supports foreign constraints on "INNO DB" tables, the first step is to make sure the tables you are using are of that type.

To setup a foreign key so that the PID column in a table named CHILD references the ID column in a table named PARENT, you can do the following:

  1. For both tables, go to the operations tab and change their type to "INNO DB"
  2. Make sure ID is the primary key (or at least an indexed column) of the PARENT table.
  3. In the CHILD table, define an index for the PID column.
  4. While viewing the structure tab of the CHILD table, click the "relation view" link just above the "add fields" section.
  5. You will be given a table where each row corresponds to an indexed column in your CLIENT table. The first dropdown in each row lets you choose which TABLE->COLUMN the indexed column references. In the row for PID, choose PARENT->ID from the dropdown and click GO.

By doing an export on the CHILD table, you should see a foreign key constraint has been created for the PID column.

MySql Proccesslist filled with "Sleep" Entries leading to "Too many Connections"?

Increasing number of max-connections will not solve the problem.

We were experiencing the same situation on our servers. This is what happens

User open a page/view, that connect to the database, query the database, still query(queries) were not finished and user leave the page or move to some other page. So the connection that was open, will remains open, and keep increasing number of connections, if there are more users connecting with the db and doing something similar.

You can set interactive_timeout MySQL, bydefault it is 28800 (8hours) to 1 hour

SET interactive_timeout=3600

Postgres password authentication fails

Assuming, that you have root access on the box you can do:

sudo -u postgres psql

If that fails with a database "postgres" does not exists this block.

sudo -u postgres psql template1

Then sudo nano /etc/postgresql/11/main/pg_hba.conf file

local   all         postgres                          ident

For newer versions of PostgreSQL ident actually might be peer.

Inside the psql shell you can give the DB user postgres a password:

ALTER USER postgres PASSWORD 'newPassword';

How do I install a NuGet package .nupkg file locally?

You can also use the Package Manager Console and invoke the Install-Package cmdlet by specifying the path to the directory that contains the package file in the -Source parameter:

Install-Package SomePackage -Source C:\PathToThePackageDir\

What do the crossed style properties in Google Chrome devtools mean?

In addition to the above answer I also want to highlight a case of striked out property which really surprised me.

If you are adding a background image to a div :

<div class = "myBackground">

</div>

You want to scale the image to fit in the dimensions of the div so this would be your normal class definition.

.myBackground {

 height:100px;
 width:100px;
 background: url("/img/bck/myImage.jpg") no-repeat; 
 background-size: contain;

}

but if you interchange the order as :-

.myBackground {
 height:100px;
 width:100px;
 background-size: contain;  //before the background
 background: url("/img/bck/myImage.jpg") no-repeat; 
}

then in chrome you ll see background-size as striked out. I am not sure why this is , but yeah you dont want to mess with it.

Which Java library provides base64 encoding/decoding?

Guava also has Base64 (among other encodings and incredibly useful stuff)

How to add action listener that listens to multiple buttons

You are declaring button1 in main method so you can not access it in actionPerform. You should make it global in class.

 JButton button1;
 public static void main(String[] args) {

    JFrame calcFrame = new JFrame();

    calcFrame.setSize(100, 100);
    calcFrame.setVisible(true);

    button1 = new JButton("1");
    button1.addActionListener(this);

    calcFrame.add(button1);
}

public void actionPerformed(ActionEvent e) {
    if(e.getSource() == button1)
}

How to run or debug php on Visual Studio Code (VSCode)

There is a much easier way to run PHP, no configuration needed:

  1. Install the Code Runner Extension
  2. Open the PHP code file in Text Editor
    • use shortcut Ctrl+Alt+N
    • or press F1 and then select/type Run Code,
    • or right click the Text Editor and then click Run Code in editor context menu
    • or click Run Code button in editor title menu
    • or click Run Code button in context menu of file explorer

Besides, you could select part of the PHP code and run the code snippet. Very convenient!

How do I convert a list into a string with spaces in Python?

you can iterate through it to do it

my_list = ['how', 'are', 'you']
my_string = " "
for a in my_list:
    my_string = my_string + ' ' + a
print(my_string)

output is

 how are you

you can strip it to get

how are you

like this

my_list = ['how', 'are', 'you']
my_string = " "
for a in my_list:
    my_string = my_string + ' ' + a
print(my_string.strip())

Setting background-image using jQuery CSS property

Here is my code:

$('body').css('background-image', 'url("/apo/1.jpg")');

Enjoy, friend

RESTful web service - how to authenticate requests from other services?

There are several different approaches you can take.

  1. The RESTful purists will want you to use BASIC authentication, and send credentials on every request. Their rationale is that no one is storing any state.

  2. The client service could store a cookie, which maintains a session ID. I don't personally find this as offensive as some of the purists I hear from - it can be expensive to authenticate over and over again. It sounds like you're not too fond of this idea, though.

  3. From your description, it really sounds like you might be interested in OAuth2 My experience so far, from what I've seen, is that it's kind of confusing, and kind of bleeding edge. There are implementations out there, but they're few and far between. In Java, I understand that it has been integrated into Spring3's security modules. (Their tutorial is nicely written.) I've been waiting to see if there will be an extension in Restlet, but so far, although it's been proposed, and may be in the incubator, it's still not been fully incorporated.

Moment JS - check if a date is today or in the future

Since no one seems to have mentioned it yet, the simplest way to check if a Moment date object is in the past:

momentObj.isBefore()

Or in the future:

momentObj.isAfter()

Just leave the args blank -- that'll default to now.

There's also isSameOrAfter and isSameOrBefore.

N.B. this factors in time. If you only care about the day, see Dipendu's answer.

Get enum values as List of String in Java 8

You could also do something as follow

public enum DAY {MON, TUES, WED, THU, FRI, SAT, SUN};
EnumSet.allOf(DAY.class).stream().map(e -> e.name()).collect(Collectors.toList())

or

EnumSet.allOf(DAY.class).stream().map(DAY::name).collect(Collectors.toList())

The main reason why I stumbled across this question is that I wanted to write a generic validator that validates whether a given string enum name is valid for a given enum type (Sharing in case anyone finds useful).

For the validation, I had to use Apache's EnumUtils library since the type of enum is not known at compile time.

@SuppressWarnings({ "unchecked", "rawtypes" })
public static void isValidEnumsValid(Class clazz, Set<String> enumNames) {
    Set<String> notAllowedNames = enumNames.stream()
            .filter(enumName -> !EnumUtils.isValidEnum(clazz, enumName))
            .collect(Collectors.toSet());

    if (notAllowedNames.size() > 0) {
        String validEnumNames = (String) EnumUtils.getEnumMap(clazz).keySet().stream()
            .collect(Collectors.joining(", "));

        throw new IllegalArgumentException("The requested values '" + notAllowedNames.stream()
                .collect(Collectors.joining(",")) + "' are not valid. Please select one more (case-sensitive) "
                + "of the following : " + validEnumNames);
    }
}

I was too lazy to write an enum annotation validator as shown in here https://stackoverflow.com/a/51109419/1225551

No authenticationScheme was specified, and there was no DefaultChallengeScheme found with default authentification and custom authorization

When I used policy before I set the default authentication scheme into it as well. I had modified the DefaultPolicy so it was slightly different. However the same should work for add policy as well.

services.AddAuthorization(options =>
        {
            options.AddPolicy(DefaultAuthorizedPolicy, policy =>
            {
                policy.Requirements.Add(new TokenAuthRequirement());
                policy.AuthenticationSchemes = new List<string>()
                                {
                                    CookieAuthenticationDefaults.AuthenticationScheme
                                }
            });
        });

Do take into consideration that by Default AuthenticationSchemes property uses a read only list. I think it would be better to implement that instead of List as well.

How to import NumPy in the Python shell

The message is fairly self-explanatory; your working directory should not be the NumPy source directory when you invoke Python; NumPy should be installed and your working directory should be anything but the directory where it lives.

php - get numeric index of associative array

While Fosco's answer is not wrong there is a case to be considered with this one: mixed arrays. Imagine I have an array like this:

$a = array(
  "nice",
  "car" => "fast",
  "none"
);

Now, PHP allows this kind of syntax but it has one problem: if I run Fosco's code I get 0 which is wrong for me, but why this happens?
Because when doing comparisons between strings and integers PHP converts strings to integers (and this is kinda stupid in my opinion), so when array_search() searches for the index it stops at the first one because apparently ("car" == 0) is true.
Setting array_search() to strict mode won't solve the problem because then array_search("0", array_keys($a)) would return false even if an element with index 0 exists.
So my solution just converts all indexes from array_keys() to strings and then compares them correctly:

echo array_search("car", array_map("strval", array_keys($a)));

Prints 1, which is correct.

EDIT:
As Shaun pointed out in the comment below, the same thing applies to the index value, if you happen to search for an int index like this:

$a = array(
  "foo" => "bar",
  "nice",
  "car" => "fast",
  "none"
);
$ind = 0;
echo array_search($ind, array_map("strval", array_keys($a)));

You will always get 0, which is wrong, so the solution would be to cast the index (if you use a variable) to a string like this:

$ind = 0;
echo array_search((string)$ind, array_map("strval", array_keys($a)));

How to use gitignore command in git

If you don't have a .gitignore file. You can create a new one by

touch .gitignore

And you can exclude a folder by entering the below command in the .gitignore file

/folderName

push this file into your git repository so that when a new person clone your project he don't have to add the same again

Checking for empty or null JToken in a JObject

As of C# 7 you could also use this:

if (clientsParsed["objects"] is JArray clients) 
{
    foreach (JObject item in clients.Children())
    {
        if (item["thisParameter"] as JToken itemToken) 
        {
            command.Parameters["@MyParameter"].Value = JTokenToSql(itemToken);
        }
    }
}

The is Operator checks the Type and if its corrects the Value is inside the clients variable.

Server Client send/receive simple text

CLIENT

namespace SocketKlient

{
    class Program

    {
        static Socket Klient;
        static IPEndPoint endPoint;
        static void Main(string[] args)
        {
            Klient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            string command;
            Console.WriteLine("Write IP address");
            command = Console.ReadLine();
            IPAddress Address;
            while(!IPAddress.TryParse(command, out Address)) 
            {
                Console.WriteLine("wrong IP format");
                command = Console.ReadLine();
            }
            Console.WriteLine("Write port");
            command = Console.ReadLine();

            int port;
            while (!int.TryParse(command, out port) && port > 0)
            {
                Console.WriteLine("Wrong port number");
                command = Console.ReadLine();
            }
            endPoint = new IPEndPoint(Address, port); 
            ConnectC(Address, port);
            while(Klient.Connected)
            {
                Console.ReadLine();
                Odesli();
            }
        }

        public static void ConnectC(IPAddress ip, int port)
        {
            IPEndPoint endPoint = new IPEndPoint(ip, port);
            Console.WriteLine("Connecting...");
            try
            {
                Klient.Connect(endPoint);
                Console.WriteLine("Connected!");
            }
            catch
            {
                Console.WriteLine("Connection fail!");
                return; 
            }
            Task t = new Task(WaitForMessages); 
            t.Start(); 
        }

        public static void SendM()
        {
            string message = "Actualy date is " + DateTime.Now; 
            byte[] buffer = Encoding.UTF8.GetBytes(message);
            Console.WriteLine("Sending: " + message);
            Klient.Send(buffer);
        }

        public static void WaitForMessages()
        {
            try
            {
                while (true)
                {
                    byte[] buffer = new byte[64]; 
                    Console.WriteLine("Waiting for answer");
                    Klient.Receive(buffer, 0, buffer.Length, 0); 

                    string message = Encoding.UTF8.GetString(buffer); 
                    Console.WriteLine("Answer: " + message); 
                }
            }
            catch
            {
                Console.WriteLine("Disconnected");
            }
        }
    }
}

MySQL error - #1062 - Duplicate entry ' ' for key 2

you can try adding

$db['db_debug'] = FALSE; 

in "your database file".php after that you can modify your database as you like.

How to set a single, main title above all the subplots with Pyplot?

If your subplots also have titles, you may need to adjust the main title size:

plt.suptitle("Main Title", size=16)

jQuery validate Uncaught TypeError: Cannot read property 'nodeName' of null

Extract from the oficial docs:

Requires that the parent form is validated, that is, $( "form" ).validate() is called first

more about... rules

How to prevent multiple definitions in C?

If you're using Visual Studio you could also do "#pragma once" at the top of the headerfile to achieve the same thing as the "#ifndef ..."-wrapping. Some other compilers probably support it as well .. .. However, don't do this :D Stick with the #ifndef-wrapping to achieve cross-compiler compatibility. I just wanted to let you know that you could also do #pragma once, since you'll probably meet this statement quite a bit when reading other peoples code.

Good luck with it

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

Don't put the @ before the id

new { id = "1" }

The framework "translate" it in ?Lenght when there is a mismatch in the parameter/route

How to get the file ID so I can perform a download of a file from Google Drive API on Android?

Click with the right mouse button on the file in your Google Drive. Choose the option to get a link which can be shared from the menu. You will see the file id now. Don't forget to undo the share.

How do I update all my CPAN modules to their latest versions?

Try perl -MCPAN -e "upgrade /(.\*)/". It works fine for me.

Turn off axes in subplots

import matplotlib.pyplot as plt

fig, ax = plt.subplots(2, 2)


To turn off axes for all subplots, do either:

[axi.set_axis_off() for axi in ax.ravel()]

or

map(lambda axi: axi.set_axis_off(), ax.ravel())

Cannot read property 'length' of null (javascript)

This also works - evaluate, if capital is defined. If not, this means, that capital is undefined or null (or other value, that evaluates to false in js)

if (capital && capital.length < 1) {do your stuff}

Remove credentials from Git

Answer for Mac Devices:

Go to

Applications/Utilities/Keychain Acccess

Search for git.credentials, and delete the git credentials for the desired URL.

Explode string by one or more spaces or tabs

This works:

$string = 'A   B C          D';
$arr = preg_split('/[\s]+/', $string);

determine DB2 text string length

From similar question DB2 - find and compare the lentgh of the value in a table field - add RTRIM since LENGTH will return length of column definition. This should be correct:

select * from table where length(RTRIM(fieldName))=10

UPDATE 27.5.2019: maybe on older db2 versions the LENGTH function returned the length of column definition. On db2 10.5 I have tried the function and it returns data length, not column definition length:

select fieldname
, length(fieldName) len_only
, length(RTRIM(fieldName)) len_rtrim
from (values (cast('1234567890  ' as varchar(30)) )) 
as tab(fieldName)

FIELDNAME                      LEN_ONLY    LEN_RTRIM
------------------------------ ----------- -----------
1234567890                              12          10

One can test this by using this term:

where length(fieldName)!=length(rtrim(fieldName))

path.join vs path.resolve with __dirname

const absolutePath = path.join(__dirname, some, dir);

vs.

const absolutePath = path.resolve(__dirname, some, dir);

path.join will concatenate __dirname which is the directory name of the current file concatenated with values of some and dir with platform-specific separator.

Whereas

path.resolve will process __dirname, some and dir i.e. from right to left prepending it by processing it.

If any of the values of some or dir corresponds to a root path then the previous path will be omitted and process rest by considering it as root

In order to better understand the concept let me explain both a little bit more detail as follows:-

The path.join and path.resolve are two different methods or functions of the path module provided by nodejs.

Where both accept a list of paths but the difference comes in the result i.e. how they process these paths.

path.join concatenates all given path segments together using the platform-specific separator as a delimiter, then normalizes the resulting path. While the path.resolve() process the sequence of paths from right to left, with each subsequent path prepended until an absolute path is constructed.

When no arguments supplied

The following example will help you to clearly understand both concepts:-

My filename is index.js and the current working directory is E:\MyFolder\Pjtz\node

const path = require('path');

console.log("path.join() : ", path.join());
// outputs .
console.log("path.resolve() : ", path.resolve());
// outputs current directory or equivalent to __dirname

Result

? node index.js
path.join() :  .
path.resolve() :  E:\MyFolder\Pjtz\node

path.resolve() method will output the absolute path whereas the path.join() returns . representing the current working directory if nothing is provided

When some root path is passed as arguments

const path=require('path');

console.log("path.join() : " ,path.join('abc','/bcd'));
console.log("path.resolve() : ",path.resolve('abc','/bcd'));

Result i

? node index.js
path.join() :  abc\bcd
path.resolve() :  E:\bcd

path.join() only concatenates the input list with platform-specific separator while the path.resolve() process the sequence of paths from right to left, with each subsequent path prepended until an absolute path is constructed.

How to fix nginx throws 400 bad request headers on any header testing tools?

normally, Maxim Donnie's method can find the reason. But I encountered one 400 bad request will not log to err_log. I found the reason with the help with tcpdump

PHP session handling errors

I'm using php-5.4.45 and I got the same problem.

If you are a php-fpm user, try edit php-fpm.conf and change listen.owner and listen.group to the right one. My nginx user is apache, so here I change these to params to apache, then it works well for me.

For apache user, I guess you should edit your fast-cgi params refer the two params I mention above.

error LNK2005: xxx already defined in MSVCRT.lib(MSVCR100.dll) C:\something\LIBCMT.lib(setlocal.obj)

You are mixing code that was compiled with /MD (use DLL version of CRT) with code that was compiled with /MT (use static CRT library). That cannot work, all source code files must be compiled with the same setting. Given that you use libraries that were pre-compiled with /MD, almost always the correct setting, you must compile your own code with this setting as well.

Project + Properties, C/C++, Code Generation, Runtime Library.

Beware that these libraries were probably compiled with an earlier version of the CRT, msvcr100.dll is quite new. Not sure if that will cause trouble, you may have to prevent the linker from generating a manifest. You must also make sure to deploy the DLLs you need to the target machine, including msvcr100.dll

SQL Server 2008 can't login with newly created user

You'll likely need to check the SQL Server error logs to determine the actual state (it's not reported to the client for security reasons.) See here for details.

Maven: Failed to read artifact descriptor

I had a similar problem. In my case, the version of testng in my .m2/repositories folder was corrupt, but when I deleted it & did a maven update again, everything worked fine.

How can I enable cURL for an installed Ubuntu LAMP stack?

You don't have to give version numbers. Just run:

sudo apt-get install php-curl

It worked for me. Don't forgot to restart the server:

sudo service apache2 restart

MySQL Sum() multiple columns

SELECT student, (SUM(mark1)+SUM(mark2)+SUM(mark3)....+SUM(markn)) AS Total
 FROM your_table
 GROUP BY student

Invariant Violation: Objects are not valid as a React child

My issue was simple when i faced the following error:

objects are not valid as a react child (found object with keys {...}

was just that I was passing an object with keys specified in the error while trying to render the object directly in a component using {object} expecting it to be a string

object: {
    key1: "key1",
    key2: "key2"
}

while rendering on a React Component, I used something like below

render() {
    return this.props.object;
}

but it should have been

render() {
    return this.props.object.key1;
}

How to drop a table if it exists?

I wrote a little UDF that returns 1 if its argument is the name of an extant table, 0 otherwise:

CREATE FUNCTION [dbo].[Table_exists]
(
    @TableName VARCHAR(200)
)
    RETURNS BIT
AS
BEGIN
    If Exists(select * from INFORMATION_SCHEMA.TABLES where TABLE_NAME = @TableName)
        RETURN 1;

    RETURN 0;
END

GO

To delete table User if it exists, call it like so:

IF [dbo].[Table_exists]('User') = 1 Drop table [User]

Change User Agent in UIWebView

Actually adding any header field to the NSURLRequest argument in shouldStartLoadWithRequest seems to work, because the request responds to setValue:ForHTTPHeaderField - but it doesn't actually work - the request is sent out without the header.

So I used this workaround in shouldStartLoadWithRequest which just copies the given request to a new mutable request, and re-loads it. This does in fact modify the header which is sent out.

if ( [request valueForHTTPHeaderField:@"MyUserAgent"] == nil )
{
    NSMutableURLRequest *modRequest = [request mutableCopyWithZone:NULL];
    [modRequest setValue:@"myagent" forHTTPHeaderField:@"MyUserAgent"];
    [webViewArgument loadRequest:modRequest];
    return NO;
}

Unfortunately, this still doesn't allow overriding the user-agent http header, which is apparently overwritten by Apple. I guess for overriding it you would have to manage a NSURLConnection by yourself.

How can I make the contents of a fixed element scrollable only when it exceeds the height of the viewport?

Here is the pure HTML and CSS solution.

  1. We create a container box for navbar with position: fixed; height:100%;

  2. Then we create an inner box with height: 100%; overflow-y: scroll;

  3. Next, we put out content inside that box.

Here is the code:

_x000D_
_x000D_
.nav-box{_x000D_
        position: fixed;_x000D_
        border: 1px solid #0a2b1d;_x000D_
        height:100%;_x000D_
   }_x000D_
   .inner-box{_x000D_
        width: 200px;_x000D_
        height: 100%;_x000D_
        overflow-y: scroll;_x000D_
        border: 1px solid #0A246A;_x000D_
    }_x000D_
    .tabs{_x000D_
        border: 3px solid chartreuse;_x000D_
        color:darkred;_x000D_
    }_x000D_
    .content-box p{_x000D_
      height:50px;_x000D_
      text-align:center;_x000D_
    }
_x000D_
<div class="nav-box">_x000D_
  <div class="inner-box">_x000D_
    <div class="tabs"><p>Navbar content Start</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content</p></div>_x000D_
    <div class="tabs"><p>Navbar content End</p></div>_x000D_
    </div>_x000D_
</div>_x000D_
<div class="content-box">_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
  <p>Lorem Ipsum</p>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Link to jsFiddle:

IOCTL Linux device driver

An ioctl, which means "input-output control" is a kind of device-specific system call. There are only a few system calls in Linux (300-400), which are not enough to express all the unique functions devices may have. So a driver can define an ioctl which allows a userspace application to send it orders. However, ioctls are not very flexible and tend to get a bit cluttered (dozens of "magic numbers" which just work... or not), and can also be insecure, as you pass a buffer into the kernel - bad handling can break things easily.

An alternative is the sysfs interface, where you set up a file under /sys/ and read/write that to get information from and to the driver. An example of how to set this up:

static ssize_t mydrvr_version_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    return sprintf(buf, "%s\n", DRIVER_RELEASE);
}

static DEVICE_ATTR(version, S_IRUGO, mydrvr_version_show, NULL);

And during driver setup:

device_create_file(dev, &dev_attr_version);

You would then have a file for your device in /sys/, for example, /sys/block/myblk/version for a block driver.

Another method for heavier use is netlink, which is an IPC (inter-process communication) method to talk to your driver over a BSD socket interface. This is used, for example, by the WiFi drivers. You then communicate with it from userspace using the libnl or libnl3 libraries.

htmlentities() vs. htmlspecialchars()

htmlspecialchars may be used:

  1. When there is no need to encode all characters which have their HTML equivalents.

    If you know that the page encoding match the text special symbols, why would you use htmlentities? htmlspecialchars is much straightforward, and produce less code to send to the client.

    For example:

    echo htmlentities('<Il était une fois un être>.');
    // Output: &lt;Il &eacute;tait une fois un &ecirc;tre&gt;.
    //                ^^^^^^^^                 ^^^^^^^
    
    echo htmlspecialchars('<Il était une fois un être>.');
    // Output: &lt;Il était une fois un être&gt;.
    //                ^                 ^
    

    The second one is shorter, and does not cause any problems if ISO-8859-1 charset is set.

  2. When the data will be processed not only through a browser (to avoid decoding HTML entities),

  3. If the output is XML (see the answer by Artefacto).

Conda command not found

For Conda > 4.4 follow this:

$ echo ". /home/ubuntu/miniconda2/etc/profile.d/conda.sh" >> ~/.bashrc

then you need to reload user bash so you need to log out:

exit

and then log again.

SQL Logic Operator Precedence: And and Or

And has precedence over Or, so, even if a <=> a1 Or a2

Where a And b 

is not the same as

Where a1 Or a2 And b,

because that would be Executed as

Where a1 Or (a2 And b)

and what you want, to make them the same, is the following (using parentheses to override rules of precedence):

 Where (a1 Or a2) And b

Here's an example to illustrate:

Declare @x tinyInt = 1
Declare @y tinyInt = 0
Declare @z tinyInt = 0

Select Case When @x=1 OR @y=1 And @z=1 Then 'T' Else 'F' End -- outputs T
Select Case When (@x=1 OR @y=1) And @z=1 Then 'T' Else 'F' End -- outputs F

For those who like to consult references (in alphabetic order):

How to make a progress bar

I tried a simple progress bar. It is not clickable just displays the actual percentage. There's a good explication and code here: http://ruwix.com/simple-javascript-html-css-slider-progress-bar/

How to select data where a field has a min value in MySQL?

In fact, depends what you want to get: - Just the min value:

SELECT MIN(price) FROM pieces
  • A table (multiples rows) whith the min value: Is as John Woo said above.

  • But, if can be different rows with same min value, the best is ORDER them from another column, because after or later you will need to do it (starting from John Woo answere):

    SELECT * FROM pieces WHERE price = ( SELECT MIN(price) FROM pieces) ORDER BY stock ASC

I have never set any passwords to my keystore and alias, so how are they created?

All these answers and there is STILL just one missing. When you create your auth credential in the Google API section of the dev console, make sure (especially if it is your first one) that you have clicked on the 'consent screen' option. If you don't have the 'title' and any other required field filled out the call will fail with this option.

DataAdapter.Fill(Dataset)

DataSet ds = new DataSet();

using (OleDbConnection connection = new OleDbConnection(connectionString))
using (OleDbCommand command = new OleDbCommand(query, connection))
using (OleDbDataAdapter adapter = new OleDbDataAdapter(command))
{
    adapter.Fill(ds);
}

return ds;

Java: Static vs inner class

  1. Static inner class cannot access non-static members of enclosing class. It can directly access static members (instance field and methods) of enclosing class same like the procedural style of getting value without creating object.

  2. Static inner class can declare both static and non-static members. The static methods have access to static members of main class. However, it cannot access non-static inner class members. To access members of non-static inner class, it has to create object of non-static inner class.

  3. Non-static inner class cannot declare static field and static methods. It has to be declared in either static or top level types. You will get this error on doing so saying "static fields only be declared in static or top level types".

  4. Non-static inner class can access both static and non-static members of enclosing class in procedural style of getting value, but it cannot access members of static inner class.

  5. The enclosing class cannot access members of inner classes until it creates an object of inner classes. IF main class in accessing members of non-static class it can create object of non-static inner class.

  6. If main class in accessing members of static inner class it has two cases:

    • Case 1: For static members, it can use class name of static inner class
    • Case 2: For non-static members, it can create instance of static inner class.

how to fire event on file select

<input type="file" @change="onFileChange" class="input upload-input" ref="inputFile"/>

onFileChange(e) {
    //upload file and then delete it from input 
    self.$refs.inputFile.value = ''
}

How can I remove the top and right axis in matplotlib?

(This is more of an extension comment, in addition to the comprehensive answers here.)


Note that we can hide each of these three elements independently of each other:

  • To hide the border (aka "spine"): ax.set_frame_on(False) or ax.spines['top'].set_visible(False)

  • To hide the ticks: ax.tick_params(top=False)

  • To hide the labels: ax.tick_params(labeltop=False)

scp (secure copy) to ec2 instance without password

Just tested:

Run the following command:

sudo shred -u /etc/ssh/*_key /etc/ssh/*_key.pub

Then:

  1. create ami (image of the ec2).
  2. launch from new ami(image) from step no 2 chose new keys.

css3 transition animation on load?

Not really, as CSS is applied as soon as possible, but the elements might not be drawn yet. You could guess a delay of 1 or 2 seconds, but this won't look right for most people, depending on the speed of their internet.

In addition, if you want to fade something in for instance, it would require CSS that hides the content to be delivered. If the user doesn't have CSS3 transitions then they would never see it.

I'd recommend using jQuery (for ease of use + you may wish to add animation for other UAs) and some JS like this:

$(document).ready(function() {
    $('#id_to_fade_in')
        .css({"opacity":0})   // Set to 0 as soon as possible – may result in flicker, but it's not hidden for users with no JS (Googlebot for instance!)
        .delay(200)           // Wait for a bit so the user notices it fade in
        .css({"opacity":1});  // Fade it back in. Swap css for animate in legacy browsers if required.
});

Along with the transitions added in the CSS. This has the advantage of easily allowing the use of animate instead of the second CSS in legacy browsers if required.

Scroll to the top of the page using JavaScript?

A lot of users recommend selecting both the html and body tags for cross-browser compatibility, like so:

$('html, body').animate({ scrollTop: 0 }, callback);

This can trip you up though if you're counting on your callback running only once. It will in fact run twice because you've selected two elements.

If that is a problem for you, you can do something like this:

function scrollToTop(callback) {
    if ($('html').scrollTop()) {
        $('html').animate({ scrollTop: 0 }, callback);
        return;
    }

    $('body').animate({ scrollTop: 0 }, callback);
}

The reason this works is in Chrome $('html').scrollTop() returns 0, but not in other browsers such as Firefox.

If you don't want to wait for the animation to complete in the case that the scrollbar is already at the top, try this:

function scrollToTop(callback) {
    if ($('html').scrollTop()) {
        $('html').animate({ scrollTop: 0 }, callback);
        return;
    }

    if ($('body').scrollTop()) {
        $('body').animate({ scrollTop: 0 }, callback);
        return;
    }

    callback();
}

Git: which is the default configured remote for branch?

For the sake of completeness: the previous answers tell how to set the upstream branch, but not how to see it.

There are a few ways to do this:

git branch -vv shows that info for all branches. (formatted in blue in most terminals)

cat .git/config shows this also.

For reference:

Data structure for maintaining tabular data in memory?

I personally wrote a lib for pretty much that quite recently, it is called BD_XML

as its most fundamental reason of existence is to serve as a way to send data back and forth between XML files and SQL databases.

It is written in Spanish (if that matters in a programming language) but it is very simple.

from BD_XML import Tabla

It defines an object called Tabla (Table), it can be created with a name for identification an a pre-created connection object of a pep-246 compatible database interface.

Table = Tabla('Animals') 

Then you need to add columns with the agregar_columna (add_column) method, with can take various key word arguments:

  • campo (field): the name of the field

  • tipo (type): the type of data stored, can be a things like 'varchar' and 'double' or name of python objects if you aren't interested in exporting to a data base latter.

  • defecto (default): set a default value for the column if there is none when you add a row

  • there are other 3 but are only there for database tings and not actually functional

like:

Table.agregar_columna(campo='Name', tipo='str')
Table.agregar_columna(campo='Year', tipo='date')
#declaring it date, time, datetime or timestamp is important for being able to store it as a time object and not only as a number, But you can always put it as a int if you don't care for dates
Table.agregar_columna(campo='Priority', tipo='int')

Then you add the rows with the += operator (or + if you want to create a copy with an extra row)

Table += ('Cat', date(1998,1,1), 1)
Table += {'Year':date(1998,1,1), 'Priority':2, Name:'Fish'}
#…
#The condition for adding is that is a container accessible with either the column name or the position of the column in the table

Then you can generate XML and write it to a file with exportar_XML (export_XML) and escribir_XML (write_XML):

file = os.path.abspath(os.path.join(os.path.dirname(__file__), 'Animals.xml'))
Table.exportar_xml()
Table.escribir_xml(file)

And then import it back with importar_XML (import_XML) with the file name and indication that you are using a file and not an string literal:

Table.importar_xml(file, tipo='archivo')
#archivo means file

Advanced

This are ways you can use a Tabla object in a SQL manner.

#UPDATE <Table> SET Name = CONCAT(Name,' ',Priority), Priority = NULL WHERE id = 2
for row in Table:
    if row['id'] == 2:
        row['Name'] += ' ' + row['Priority']
        row['Priority'] = None
print(Table)

#DELETE FROM <Table> WHERE MOD(id,2) = 0 LIMIT 1
n = 0
nmax = 1
for row in Table:
    if row['id'] % 2 == 0:
        del Table[row]
        n += 1
        if n >= nmax: break
print(Table)

this examples assume a column named 'id' but can be replaced width row.pos for your example.

if row.pos == 2:

The file can be download from:

https://bitbucket.org/WolfangT/librerias

How to create a generic array in Java?

To extend to more dimensions, just add []'s and dimension parameters to newInstance() (T is a type parameter, cls is a Class<T>, d1 through d5 are integers):

T[] array = (T[])Array.newInstance(cls, d1);
T[][] array = (T[][])Array.newInstance(cls, d1, d2);
T[][][] array = (T[][][])Array.newInstance(cls, d1, d2, d3);
T[][][][] array = (T[][][][])Array.newInstance(cls, d1, d2, d3, d4);
T[][][][][] array = (T[][][][][])Array.newInstance(cls, d1, d2, d3, d4, d5);

See Array.newInstance() for details.

Progress Bar with HTML and CSS

http://jsfiddle.net/cwZSW/1406/

_x000D_
_x000D_
#progress {_x000D_
    background: #333;_x000D_
    border-radius: 13px;_x000D_
    height: 20px;_x000D_
    width: 300px;_x000D_
    padding: 3px;_x000D_
}_x000D_
_x000D_
#progress:after {_x000D_
    content: '';_x000D_
    display: block;_x000D_
    background: orange;_x000D_
    width: 50%;_x000D_
    height: 100%;_x000D_
    border-radius: 9px;_x000D_
}
_x000D_
<div id="progress"></div>
_x000D_
_x000D_
_x000D_

How do I reverse a C++ vector?

#include<algorithm>
#include<vector>
#include<iostream>
using namespace std;
int main()
{
    vector<int>v1;
    for(int i=0; i<5; i++)
        v1.push_back(i*2);
    for(int i=0; i<v1.size(); i++)
        cout<<v1[i];    //02468
    reverse(v1.begin(),v1.end());
    
    for(int i=0; i<v1.size(); i++)
        cout<<v1[i];   //86420
}

Simple working Example of json.net in VB.net

Your class JSON_result does not match your JSON string. Note how the object JSON_result is going to represent is wrapped in another property named "Venue".

So either create a class for that, e.g.:

Public Class Container
    Public Venue As JSON_result
End Class

Public Class JSON_result
    Public ID As Integer
    Public Name As String
    Public NameWithTown As String
    Public NameWithDestination As String
    Public ListingType As String
End Class

Dim obj = JsonConvert.DeserializeObject(Of Container)(...your_json...)

or change your JSON string to

{
    "ID": 3145,
    "Name": "Big Venue, Clapton",
    "NameWithTown": "Big Venue, Clapton, London",
    "NameWithDestination": "Big Venue, Clapton, London",
    "ListingType": "A",
    "Address": {
        "Address1": "Clapton Raod",
        "Address2": "",
        "Town": "Clapton",
        "County": "Greater London",
        "Postcode": "PO1 1ST",
        "Country": "United Kingdom",
        "Region": "Europe"
    },
    "ResponseStatus": {
        "ErrorCode": "200",
        "Message": "OK"
    }
}

or use e.g. a ContractResolver to parse the JSON string.

New og:image size for Facebook share?

UPDATE: The image size Must be larger than (600 x 315px)

The image size can be any size because Faceboook re-size the image width & height.

The default height is 208px & width is 398px for a post permalink:

www.facebook.com/{username}/posts/{post_id}

But for a timeline view:

www.facebook.com/{username}

width is 377px & height is 197px

I hope this will help you!

How to start an Intent by passing some parameters to it?

putExtra() : This method sends the data to another activity and in parameter, we have to pass key-value pair.

Syntax: intent.putExtra("key", value);

Eg: intent.putExtra("full_name", "Vishnu Sivan");

Intent intent=getIntent() : It gets the Intent from the previous activity.

fullname = intent.getStringExtra(“full_name”) : This line gets the string form previous activity and in parameter, we have to pass the key which we have mentioned in previous activity.

Sample Code:

Intent intent = new Intent(getApplicationContext(), MainActivity.class);
intent.putExtra("firstName", "Vishnu");
intent.putExtra("lastName", "Sivan");
startActivity(intent);

How to use UTF-8 in resource properties with ResourceBundle

ResourceBundle.Control with UTF-8 and new String methods don't work, if the properties file uses cp1251 charset, for example.

So I recomended using a common method: write in unicode symbols. For this:

IDEA -- has a special "Transparent native-to-ASCII conversion" option (Settings > File Encoding).

Eclipse -- has a plugin "Properties Editor". It can work as separate application.

Upload File With Ajax XmlHttpRequest

  1. There is no such thing as xhr.file = file;; the file object is not supposed to be attached this way.
  2. xhr.send(file) doesn't send the file. You have to use the FormData object to wrap the file into a multipart/form-data post data object:

    var formData = new FormData();
    formData.append("thefile", file);
    xhr.send(formData);
    

After that, the file can be access in $_FILES['thefile'] (if you are using PHP).

Remember, MDC and Mozilla Hack demos are your best friends.

EDIT: The (2) above was incorrect. It does send the file, but it would send it as raw post data. That means you would have to parse it yourself on the server (and it's often not possible, depend on server configuration). Read how to get raw post data in PHP here.

How to get root directory in yii2

Open file D:\wamp\www\yiistore2\common\config\params-local.php

Paste below code before return

Yii::setAlias('@anyname', realpath(dirname(__FILE__).'/../../'));

After inserting above code in params-local.php file your file should look like this.

Yii::setAlias('@anyname', realpath(dirname(__FILE__).'/../../'));

return [
];

Now to get path of your root (in my case its D:\wamp\www\yiistore2) directory you can use below code in any php file.

echo Yii::getAlias('@anyname');

_DEBUG vs NDEBUG

Be consistent and it doesn't matter which one. Also if for some reason you must interop with another program or tool using a certain DEBUG identifier it's easy to do

#ifdef THEIRDEBUG
#define MYDEBUG
#endif //and vice-versa

Deploying just HTML, CSS webpage to Tomcat

There is no real need to create a war to run it from Tomcat. You can follow these steps

  1. Create a folder in webapps folder e.g. MyApp

  2. Put your html and css in that folder and name the html file, which you want to be the starting page for your application, index.html

  3. Start tomcat and point your browser to url "http://localhost:8080/MyApp". Your index.html page will pop up in the browser

java.io.FileNotFoundException: the system cannot find the file specified

Put the word.txt directly as a child of the project root folder and a peer of src

Project_Root
    src
    word.txt

Disclaimer: I'd like to explain why this works for this particular case and why it may not work for others.

Why it works:

When you use File or any of the other FileXxx variants, you are looking for a file on the file system relative to the "working directory". The working directory, can be described as this:

When you run from the command line

C:\EclipseWorkspace\ProjectRoot\bin > java com.mypackage.Hangman1

the working directory is C:\EclipseWorkspace\ProjectRoot\bin. With your IDE (at least all the ones I've worked with), the working directory is the ProjectRoot. So when the file is in the ProjectRoot, then using just the file name as the relative path is valid, because it is at the root of the working directory.

Similarly, if this was your project structure ProjectRoot\src\word.txt, then the path "src/word.txt" would be valid.

Why it May not Work

For one, the working directory could always change. For instance, running the code from the command line like in the example above, the working directory is the bin. So in this case it will fail, as there is not bin\word.txt

Secondly, if you were to export this project into a jar, and the file was configured to be included in the jar, it would also fail, as the path will no longer be valid either.

That being said, you need to determine if the file is to be an (or just "resource" - terms which sometimes I'll use interchangeably). If so, then you will want to build the file into the classpath, and access it via an URL. First thing you would need to do (in this particular) case is make sure that the file get built into the classpath. With the file in the project root, you must configure the build to include the file. But if you put the file in the src or in some directory below, then the default build should put it into the class path.

You can access classpath resource in a number of ways. You can make use of the Class class, which has getResourceXxx method, from which you use to obtain classpath resources.

For example, if you changed your project structure to ProjectRoot\src\resources\word.txt, you could use this:

InputStream is = Hangman1.class.getResourceAsStream("/resources/word.txt");
BufferedReader reader = new BufferedReader(new InputStreamReader(is));

getResourceAsStream returns an InputStream, but obtains an URL under the hood. Alternatively, you could get an URL if that's what you need. getResource() will return an URL

For Maven users, where the directory structure is like src/main/resources, the contents of the resources folder is put at the root of the classpath. So if you have a file in there, then you would only use getResourceAsStream("/thefile.txt")

SQL update fields of one table from fields of another one

You can use the non-standard FROM clause.

UPDATE b
SET column1 = a.column1,
  column2 = a.column2,
  column3 = a.column3
FROM a
WHERE a.id = b.id
AND b.id = 1

Binding a Button's visibility to a bool value in ViewModel

Generally there are two ways to do it, a converter class or a property in the Viewmodel that essentially converts the value for you.

I tend to use the property approach if it is a one off conversion. If you want to reuse it, use the converter. Below, find an example of the converter:

<ValueConversion(GetType(Boolean), GetType(Visibility))> _
Public Class BoolToVisibilityConverter
    Implements IValueConverter

    Public Function Convert(ByVal value As Object, ByVal targetType As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.Convert

        If value IsNot Nothing Then
            If value = True Then 
                Return Visibility.Visible
            Else
                Return Visibility.Collapsed
            End If
        Else
            Return Visibility.Collapsed
        End If
    End Function

    Public Function ConvertBack(ByVal value As Object, ByVal targetType As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.ConvertBack
        Throw New NotImplementedException
    End Function
End Class

A ViewModel property method would just check the boolean property value, and return a visibility based on that. Be sure to implement INotifyPropertyChanged and call it on both the Boolean and Visibility properties to updated properly.

How to make child divs always fit inside parent div?

In your example, you can't: the 5px margin is added to the bounding box of div#two and div#three effectively making their width and height 100% of parent + 5px, which will overflow.

You can use padding on the parent Element to ensure there's 5px of space inside its border:

<style>
    html, body {width:100%;height:100%;margin:0;padding:0;}
    .border {border:1px solid black;}
    #one {padding:5px;width:500px;height:300px;}
    #two {width:100%;height:50px;}
    #three {width:100px;height:100%;}
</style>

EDIT: In testing, removing the width:100% from div#two will actually let it work properly as divs are block-level and will always fill their parents' widths by default. That should clear your first case if you'd like to use margin.

Parse v. TryParse

TryParse does not return the value, it returns a status code to indicate whether the parse succeeded (and doesn't throw an exception).

Deleting DataFrame row in Pandas based on column value

Just adding another way for DataFrame expanded over all columns:

for column in df.columns:
   df = df[df[column]!=0]

Example:

def z_score(data,count):
   threshold=3
   for column in data.columns:
       mean = np.mean(data[column])
       std = np.std(data[column])
       for i in data[column]:
           zscore = (i-mean)/std
           if(np.abs(zscore)>threshold):
               count=count+1
               data = data[data[column]!=i]
   return data,count

Free Rest API to retrieve current datetime as string (timezone irrelevant)

This API gives you the current time and several formats in JSON - https://market.mashape.com/parsify/format#time. Here's a sample response:

{
  "time": {
    "daysInMonth": 31,
    "millisecond": 283,
    "second": 42,
    "minute": 55,
    "hour": 1,
    "date": 6,
    "day": 3,
    "week": 10,
    "month": 2,
    "year": 2013,
    "zone": "+0000"
  },
  "formatted": {
    "weekday": "Wednesday",
    "month": "March",
    "ago": "a few seconds",
    "calendar": "Today at 1:55 AM",
    "generic": "2013-03-06T01:55:42+00:00",
    "time": "1:55 AM",
    "short": "03/06/2013",
    "slim": "3/6/2013",
    "hand": "Mar 6 2013",
    "handTime": "Mar 6 2013 1:55 AM",
    "longhand": "March 6 2013",
    "longhandTime": "March 6 2013 1:55 AM",
    "full": "Wednesday, March 6 2013 1:55 AM",
    "fullSlim": "Wed, Mar 6 2013 1:55 AM"
  },
  "array": [
    2013,
    2,
    6,
    1,
    55,
    42,
    283
  ],
  "offset": 1362534942283,
  "unix": 1362534942,
  "utc": "2013-03-06T01:55:42.283Z",
  "valid": true,
  "integer": false,
  "zone": 0
}

How do I filter query objects by date range in Django?

Is simple,

YourModel.objects.filter(YOUR_DATE_FIELD__date=timezone.now())

Works for me

How do you completely remove the button border in wpf?

I don't know why others haven't pointed out that this question is duplicated with this one with accepted answer.

I quote here the solution: You need to override the ControlTemplate of the Button:

<Button Content="save" Name="btnSaveEditedText" 
                Background="Transparent" 
                Foreground="White" 
                FontFamily="Tw Cen MT Condensed" 
                FontSize="30" 
                Margin="-280,0,0,10"
                Width="60"
                BorderBrush="Transparent"
                BorderThickness="0">
    <Button.Template>
        <ControlTemplate TargetType="Button">
             <ContentPresenter Content="{TemplateBinding Content}"/>
        </ControlTemplate>
    </Button.Template>  
</Button>

Set the selected index of a Dropdown using jQuery

You want to grab the value of the first option in the select element.

$("*[id$='" + originalId + "']").val($("*[id$='" + originalId + "'] option:first").attr('value'));

How do I turn off the mysql password validation?

You can configure this in mysql configuration file open /etc/my.cnf file In this file all the lines which is configuring the password policy make those commented like

#validate-password=FORCE_PLUS_PERMANENT
#validate_password_length=10
#validate_password_mixed_case_count=1
#validate_password_number_count=1
#validate_password_policy=MEDIUM

Uncomment and change the value of the properties you want to change.

How to find the php.ini file used by the command line?

Just run php --ini and look for Loaded Configuration File in output for the location of php.ini used by your CLI

Converting a value to 2 decimal places within jQuery

you can use just javascript for it

var total =10.8
(total).toFixed(2); 10.80


alert(total.toFixed(2))); 

Use dynamic variable names in `dplyr`

In the new release of dplyr (0.6.0 awaiting in April 2017), we can also do an assignment (:=) and pass variables as column names by unquoting (!!) to not evaluate it

 library(dplyr)
 multipetalN <- function(df, n){
      varname <- paste0("petal.", n)
      df %>%
         mutate(!!varname := Petal.Width * n)
 }

 data(iris)
 iris1 <- tbl_df(iris)
 iris2 <- tbl_df(iris)
 for(i in 2:5) {
     iris2 <- multipetalN(df=iris2, n=i)
 }   

Checking the output based on @MrFlick's multipetal applied on 'iris1'

identical(iris1, iris2)
#[1] TRUE

How to check if a file exists from inside a batch file

Try something like the following example, quoted from the output of IF /? on Windows XP:

IF EXIST filename. (
    del filename.
) ELSE (
    echo filename. missing.
)

You can also check for a missing file with IF NOT EXIST.

The IF command is quite powerful. The output of IF /? will reward careful reading. For that matter, try the /? option on many of the other built-in commands for lots of hidden gems.  

Command to open file with git

To open a file in git, with windows you will type explorer . , notice the space between explorer and the dot. On mac you can open it with open . , and in Linux with nautilus . , notice the period at the end of each one.

How to use XPath preceding-sibling correctly

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

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

jQuery keypress() event not firing?

With jQuery, I've done it this way:

function checkKey(e){
     switch (e.keyCode) {
        case 40:
            alert('down');
            break;
        case 38:
            alert('up');
            break;
        case 37:
            alert('left');
            break;
        case 39:
            alert('right');
            break;
        default:
            alert('???');  
            }      
}

if ($.browser.mozilla) {
    $(document).keypress (checkKey);
} else {
    $(document).keydown (checkKey);
}

Also, try these plugins, which looks like they do all that work for you:

http://www.openjs.com/scripts/events/keyboard_shortcuts

http://www.webappers.com/2008/07/31/bind-a-hot-key-combination-with-jquery-hotkeys/

How to return an array from a function?

int* test();

but it would be "more C++" to use vectors:

std::vector< int > test();

EDIT
I'll clarify some point. Since you mentioned C++, I'll go with new[] and delete[] operators, but it's the same with malloc/free.

In the first case, you'll write something like:

int* test() {
    return new int[size_needed];
}

but it's not a nice idea because your function's client doesn't really know the size of the array you are returning, although the client can safely deallocate it with a call to delete[].

int* theArray = test();
for (size_t i; i < ???; ++i) { // I don't know what is the array size!
    // ...
}
delete[] theArray; // ok.

A better signature would be this one:

int* test(size_t& arraySize) {
    array_size = 10;
    return new int[array_size];
}

And your client code would now be:

size_t theSize = 0;
int* theArray = test(theSize);
for (size_t i; i < theSize; ++i) { // now I can safely iterate the array
    // ...
}
delete[] theArray; // still ok.

Since this is C++, std::vector<T> is a widely-used solution:

std::vector<int> test() {
    std::vector<int> vector(10);
    return vector;
}

Now you don't have to call delete[], since it will be handled by the object, and you can safely iterate it with:

std::vector<int> v = test();
std::vector<int>::iterator it = v.begin();
for (; it != v.end(); ++it) {
   // do your things
}

which is easier and safer.

Passing arguments to require (when loading module)

Based on your comments in this answer, I do what you're trying to do like this:

module.exports = function (app, db) {
    var module = {};

    module.auth = function (req, res) {
        // This will be available 'outside'.
        // Authy stuff that can be used outside...
    };

    // Other stuff...
    module.pickle = function(cucumber, herbs, vinegar) {
        // This will be available 'outside'.
        // Pickling stuff...
    };

    function jarThemPickles(pickle, jar) {
        // This will be NOT available 'outside'.
        // Pickling stuff...

        return pickleJar;
    };

    return module;
};

I structure pretty much all my modules like that. Seems to work well for me.

AngularJS ng-style with a conditional expression

For single css property

ng-style="1==1 && {'color':'red'}"

For multiple css properties below can be referred

ng-style="1==1 && {'color':'red','font-style': 'italic'}"

Replace 1==1 with your condition expression

Jquery each - Stop loop and return object

Because when you use a return statement inside an each loop, a "non-false" value will act as a continue, whereas false will act as a break. You will need to return false from the each function. Something like this:

function findXX(word) {
    var toReturn; 
    $.each(someArray, function(i) {
        $('body').append('-> '+i+'<br />');
        if(someArray[i] == word) {
            toReturn = someArray[i];
            return false;
        }   
    }); 
    return toReturn; 
}

From the docs:

We can break the $.each() loop at a particular iteration by making the callback function return false. Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.

Matching a Forward Slash with a regex

I encountered two issues related to the foregoing, when extracting text delimited by \ and /, and found a solution that fits both, other than using new RegExp, which requires \\\\ at the start. These findings are in Chrome and IE11.

The regular expression

/\\(.*)\//g

does not work. I think the // is interpreted as the start of a comment in spite of the escape character. The regular expression (equally valid in my case though not in general)

/\b/\\(.*)\/\b/g

does not work either. I think the second / terminates the regular expression in spite of the escape character.

What does work for me is to represent / as \x2F, which is the hexadecimal representation of /. I think that's more efficient and understandable than using new RegExp, but of course it needs a comment to identify the hex code.

404 Not Found The requested URL was not found on this server

If your .htaccess file is ok and the problem persist try to make the AllowOverride directive enabled in your httpd.conf. If the AllowOverride directive is set to None in your Apache httpd.config file, then .htaccess files are completely ignored. Example of enabled AllowOverride directive in httpd.config:

 <Directory />
    Options FollowSymLinks
    **AllowOverride All**
 </Directory>

Therefor restart your server.

Adding a view controller as a subview in another view controller

Please also check the official documentation on implementing a custom container view controller:

https://developer.apple.com/library/content/featuredarticles/ViewControllerPGforiPhoneOS/ImplementingaContainerViewController.html#//apple_ref/doc/uid/TP40007457-CH11-SW1

This documentation has much more detailed information for every instruction and also describes how to do add transitions.

Translated to Swift 3:

func cycleFromViewController(oldVC: UIViewController,
               newVC: UIViewController) {
   // Prepare the two view controllers for the change.
   oldVC.willMove(toParentViewController: nil)
   addChildViewController(newVC)

   // Get the start frame of the new view controller and the end frame
   // for the old view controller. Both rectangles are offscreen.r
   newVC.view.frame = view.frame.offsetBy(dx: view.frame.width, dy: 0)
   let endFrame = view.frame.offsetBy(dx: -view.frame.width, dy: 0)

   // Queue up the transition animation.
   self.transition(from: oldVC, to: newVC, duration: 0.25, animations: { 
        newVC.view.frame = oldVC.view.frame
        oldVC.view.frame = endFrame
    }) { (_: Bool) in
        oldVC.removeFromParentViewController()
        newVC.didMove(toParentViewController: self)
    }
}

How to add double quotes to a string that is inside a variable?

An indirect, but simple to understand alternative to add quotes at start and end of string -

char quote = '"';

string modifiedString = quote + "Original String" + quote;

What does "collect2: error: ld returned 1 exit status" mean?

The ld returned 1 exit status error is the consequence of previous errors. In your example there is an earlier error - undefined reference to 'clrscr' - and this is the real one. The exit status error just signals that the linking step in the build process encountered some errors. Normally exit status 0 means success, and exit status > 0 means errors.

When you build your program, multiple tools may be run as separate steps to create the final executable. In your case one of those tools is ld, which first reports the error it found (clrscr reference missing), and then it returns the exit status. Since the exit status is > 0, it means an error and is reported.

In many cases tools return as the exit status the number of errors they encountered. So if ld tool finds two errors, its exit status would be 2.

Linq: GroupBy, Sum and Count

I don't understand where the first "result with sample data" is coming from, but the problem in the console app is that you're using SelectMany to look at each item in each group.

I think you just want:

List<ResultLine> result = Lines
    .GroupBy(l => l.ProductCode)
    .Select(cl => new ResultLine
            {
                ProductName = cl.First().Name,
                Quantity = cl.Count().ToString(),
                Price = cl.Sum(c => c.Price).ToString(),
            }).ToList();

The use of First() here to get the product name assumes that every product with the same product code has the same product name. As noted in comments, you could group by product name as well as product code, which will give the same results if the name is always the same for any given code, but apparently generates better SQL in EF.

I'd also suggest that you should change the Quantity and Price properties to be int and decimal types respectively - why use a string property for data which is clearly not textual?

Codesign wants to access key "access" in your keychain, I put in my login password but keeps asking me

Solve this problem by doing this.

  1. Enter your Mac Login Password and Choose "Always Allow"

  2. One or More dialogs opened and positioned in the same dialog, repeat step 1 until all dialogs closed. (So you thought your password wrong but repeat "Always Allow" with your Mac login password tricky part :) )

Hope it will work.

Evaluate a string with a switch in C++

A switch statement can only be used for integral values, not for values of user-defined type. And even if it could, your input operation doesn't work, either.

You might want this:

#include <string>
#include <iostream>


std::string input;

if (!std::getline(std::cin, input)) { /* error, abort! */ }

if (input == "Option 1")
{
    // ... 
}
else if (input == "Option 2")
{ 
   // ...
}

// etc.

Adding image inside table cell in HTML

You have a TH floating at the top of your table which isn't within a TR. Fix that.

With regards to your image problem you;re referencing the image absolutely from your computer's hard drive. Don't do that.

You also have a closing tag which shouldn't be there.

It should be:

<img src="h.gif" alt="" border="3" height="100" width="100" />

Also this:

<table border = 5 bordercolor = red align = center>

Your colspans are also messed up. You only seem to have three columns but have colspans of 14 and 4 in your code.

Should be:

<table border="5" bordercolor="red" align="center">

Also you have no DOCTYPE declared. You should at least add:

<!DOCTYPE html> 

Execute specified function every X seconds

Use System.Windows.Forms.Timer.

private Timer timer1; 
public void InitTimer()
{
    timer1 = new Timer();
    timer1.Tick += new EventHandler(timer1_Tick);
    timer1.Interval = 2000; // in miliseconds
    timer1.Start();
}

private void timer1_Tick(object sender, EventArgs e)
{
    isonline();
}

You can call InitTimer() in Form1_Load().

Batch file to copy files from one folder to another folder

If you want to copy file not using absolute path, relative path in other words:

Don't forget to write backslash in the path AND NOT slash

Example:

copy children-folder\file.something .\other-children-folder

PS: absolute path can be retrieved using these wildcards called "batch parameters"

@echo off
echo %%~dp0 is "%~dp0"
echo %%0 is "%0"
echo %%~dpnx0 is "%~dpnx0"
echo %%~f1 is "%~f1"
echo %%~dp0%%~1 is "%~dp0%~1"

Check documentation here about copy: https://technet.microsoft.com/en-us/library/bb490886.aspx

And also here for batch parameters documentation: https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/percent.mspx?mfr=true

Centering floating divs within another div

With Flexbox you can easily horizontally (and vertically) center floated children inside a div.

So if you have simple markup like so:

<div class="wpr">
    <span></span>
    <span></span>
    <span></span>
    <span></span>
    <span></span>
</div>

with CSS:

.wpr
{
    width: 400px;
    height: 100px;
    background: pink;
    padding: 10px 30px;
}

.wpr span
{
    width: 50px;
    height: 50px;
    background: green;
    float: left; /* **children floated left** */
    margin: 0 5px;
}

(This is the (expected - and undesirable) RESULT)

Now add the following rules to the wrapper:

display: flex;
justify-content: center; /* align horizontal */

and the floated children get aligned center (DEMO)

Just for fun, to get vertical alignment as well just add:

align-items: center; /* align vertical */

DEMO

How can I extract a predetermined range of lines from a text file on Unix?

You could use 'vi' and then the following command:

:16224,16482w!/tmp/some-file

Alternatively:

cat file | head -n 16482 | tail -n 258

EDIT:- Just to add explanation, you use head -n 16482 to display first 16482 lines then use tail -n 258 to get last 258 lines out of the first output.

Responsive dropdown navbar with angular-ui bootstrap (done in the correct angular kind of way)

You can do it using the "collapse" directive: http://jsfiddle.net/iscrow/Es4L3/ (check the two "Note" in the HTML).

        <!-- Note: set the initial collapsed state and change it when clicking -->
        <a ng-init="navCollapsed = true" ng-click="navCollapsed = !navCollapsed" class="btn btn-navbar">
           <span class="icon-bar"></span>
           <span class="icon-bar"></span>
           <span class="icon-bar"></span>
        </a>
        <a class="brand" href="#">Title</a>
           <!-- Note: use "collapse" here. The original "data-" settings are not needed anymore. -->
           <div collapse="navCollapsed" class="nav-collapse collapse navbar-responsive-collapse">
              <ul class="nav">

That is, you need to store the collapsed state in a variable, and changing the collapsed also by (simply) changing the value of that variable.


Release 0.14 added a uib- prefix to components:

https://github.com/angular-ui/bootstrap/wiki/Migration-guide-for-prefixes

Change: collapse to uib-collapse.

window.location.href doesn't redirect

In case anyone was a tired and silly as I was the other night whereupon I came across many threads espousing the different methods to get a javascript redirect, all of which were failing...

You can't use window.location.replace or document.location.href or any of your favourite vanilla javascript methods to redirect a page to itself.

So if you're dynamically adding in the redirect path from the back end, or pulling it from a data tag, make sure you do check at some stage for redirects to the current page. It could be as simple as:

if(window.location.href == linkout)
{
    location.reload();
}
else
{
    window.location.href = linkout;
}

What is the difference between :focus and :active?

:focus and :active are two different states.

  • :focus represents the state when the element is currently selected to receive input and
  • :active represents the state when the element is currently being activated by the user.

For example let's say we have a <button>. The <button> will not have any state to begin with. It just exists. If we use Tab to give "focus" to the <button>, it now enters its :focus state. If you then click (or press space), you then make the button enter its (:active) state.

On that note, when you click on an element, you give it focus, which also cultivates the illusion that :focus and :active are the same. They are not the same. When clicked the button is in :focus:active state.

An example:

_x000D_
_x000D_
<style type="text/css">_x000D_
  button { font-weight: normal; color: black; }_x000D_
  button:focus { color: red; }_x000D_
  button:active { font-weight: bold; }_x000D_
</style>_x000D_
  _x000D_
<button>_x000D_
  When clicked, my text turns red AND bold!<br />_x000D_
  But not when focused only,<br />_x000D_
 where my text just turns red_x000D_
</button>
_x000D_
_x000D_
_x000D_

edit: jsfiddle

How to push both value and key into PHP array

hi i had same problem i find this solution you should use two arrays then combine them both

 <?php

$fname=array("Peter","Ben","Joe");

$age=array("35","37","43");

$c=array_combine($fname,$age);

print_r($c);

?>

reference : w3schools

If...Then...Else with multiple statements after Then

This works with multiple statements:

if condition1 Then stmt1:stmt2 Else if condition2 Then stmt3:stmt4 Else stmt5:stmt6

Or you can split it over multiple lines:

if condition1 Then stmt1:stmt2
Else if condition2 Then stmt3:stmt4
Else stmt5:stmt6

Wait until boolean value changes it state

public Boolean test() throws InterruptedException {
    BlockingQueue<Boolean> booleanHolder = new LinkedBlockingQueue<>();
    new Thread(() -> {
        try {
            TimeUnit.SECONDS.sleep(2);
            booleanHolder.put(true);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }).start();
    return booleanHolder.poll(4, TimeUnit.SECONDS);
}

Android splash screen image sizes to fit all devices

PORTRAIT MODE

MDPI is 320x480 dp = 320x480px (1x)

LDPI is 0.75 x MDPI = 240x360px

HDPI is 1.5 x MDPI = 480x720px

XHDPI is 2 x MDPI = 640x960px

XXHDPI is 3 x MDPI = 960x1440px

XXXHDPI is 4 x MDPI = 1280x1920px

LANDSCAPE MODE

MDPI is 480x320 dp = 480x320px (1x)

LDPI is 0.75 x MDPI = 360x240px

HDPI is 1.5 x MDPI = 720x480px

XHDPI is 2 x MDPI = 960x640px

XXHDPI is 3 x MDPI = 1440x960px

XXXHDPI is 4 x MDPI = 1920x1280px

EDIT:

I would suggest to use Lottie for splash screen if you are reading this in 2019+

Forking vs. Branching in GitHub

It has to do with the general workflow of Git. You're unlikely to be able to push directly to the main project's repository. I'm not sure if GitHub project's repository support branch-based access control, as you wouldn't want to grant anyone the permission to push to the master branch for example.

The general pattern is as follows:

  • Fork the original project's repository to have your own GitHub copy, to which you'll then be allowed to push changes.
  • Clone your GitHub repository onto your local machine
  • Optionally, add the original repository as an additional remote repository on your local repository. You'll then be able to fetch changes published in that repository directly.
  • Make your modifications and your own commits locally.
  • Push your changes to your GitHub repository (as you generally won't have the write permissions on the project's repository directly).
  • Contact the project's maintainers and ask them to fetch your changes and review/merge, and let them push back to the project's repository (if you and them want to).

Without this, it's quite unusual for public projects to let anyone push their own commits directly.

org.apache.http.conn.HttpHostConnectException: Connection to http://localhost refused in android

try adding the permission outside the application tag of the manifest in addition to the above mentioned answers of changing localhost to 10.0.2.2:8080

C compile : collect2: error: ld returned 1 exit status

When compiling your program, you need to include dict.c as well, eg:

gcc -o test1 test1.c dict.c

Plus you have a typo in dict.c definition of CreateDictionary, it says CreateDectionary (e instead of i)

jQuery call function after load

$(document).ready(my_function);

Or

$(document).ready(function () {
  // Function code here.
});

Or the shorter but less readable variant:

$(my_function);

All of these will cause my_function to be called after the DOM loads.

See the ready event documentation for more details.

Binds a function to be executed whenever the DOM is ready to be traversed and manipulated.

Edit:

To simulate a click, use the click() method without arguments:

$('#button').click();

From the docs:

Triggers the click event of each matched element. Causes all of the functions that have been bound to that click event to be executed.

To put it all together, the following code simulates a click when the document finishes loading:

$(function () {
  $('#button').click();
});

SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax — PHP — PDO

I've got this exact error, but in my case I was binding values for the LIMIT clause without specifying the type. I'm just dropping this here in case somebody gets this error for the same reason. Without specifying the type LIMIT :limit OFFSET :offset; resulted in LIMIT '10' OFFSET '1'; instead of LIMIT 10 OFFSET 1;. What helps to correct that is the following:

$stmt->bindParam(':limit', intval($limit, 10), \PDO::PARAM_INT);
$stmt->bindParam(':offset', intval($offset, 10), \PDO::PARAM_INT);

The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions

ORDER BY column OFFSET 0 ROWS

Surprisingly makes it work, what a strange feature.

A bigger example with a CTE as a way to temporarily "store" a long query to re-order it later:

;WITH cte AS (
    SELECT .....long select statement here....
)

SELECT * FROM 
(
    SELECT * FROM 
    ( -- necessary to nest selects for union to work with where & order clauses
        SELECT * FROM cte WHERE cte.MainCol= 1 ORDER BY cte.ColX asc OFFSET 0 ROWS 
    ) first
    UNION ALL
    SELECT * FROM 
    (  
        SELECT * FROM cte WHERE cte.MainCol = 0 ORDER BY cte.ColY desc OFFSET 0 ROWS 
    ) last
) as unionized
ORDER BY unionized.MainCol desc -- all rows ordered by this one
OFFSET @pPageSize * @pPageOffset ROWS -- params from stored procedure for pagination, not relevant to example
FETCH FIRST @pPageSize ROWS ONLY -- params from stored procedure for pagination, not relevant to example

So we get all results ordered by MainCol

But the results with MainCol = 1 get ordered by ColX

And the results with MainCol = 0 get ordered by ColY

How can I view array structure in JavaScript with alert()?

A very basic approach is alert(arrayObj.join('\n')), which will display each array element in a row.

Android Studio Image Asset Launcher Icon Background Color

You have two ways:

1) In Background Layer > Scaling, reduce the Resize to 1

enter image description here

and then in Legacy > Legacy Icon set Shape as None

enter image description here


2) in Background Layer > Scaling > Source Asset, you can set an image as a 1x1 pixel (or any size) transparent.png image (you've already created).

enter image description here

and then in Legacy > Legacy Icon set Shape as None

enter image description here

Convert object to JSON in Android

Might be better choice:

@Override
public String toString() {
    return new GsonBuilder().create().toJson(this, Producto.class);
}

What port number does SOAP use?

SOAP (communication protocol) for communication between applications. Uses HTTP (port 80) or SMTP ( port 25 or 2525 ), for message negotiation and transmission.

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

For Windows/WSL/Cygwin etc users:

Make sure that your line endings are standard Unix line feeds, i.e. \n (LF) only.

Using Windows line endings \r\n (CRLF) line endings will break the command line break.


This is because having \ at the end of a line with Windows line ending translates to \ \r \n.
As Mark correctly explains above:

The line-continuation will fail if you have whitespace after the backslash and before the newline.

This includes not just space () or tabs (\t) but also the carriage return (\r).

Extract XML Value in bash script

I agree with Charles Duffy that a proper XML parser is the right way to go.

But as to what's wrong with your sed command (or did you do it on purpose?).

  • $data was not quoted, so $data is subject to shell's word splitting, filename expansion among other things. One of the consequences being that the spacing in the XML snippet is not preserved.

So given your specific XML structure, this modified sed command should work

title=$(sed -ne '/title/{s/.*<title>\(.*\)<\/title>.*/\1/p;q;}' <<< "$data")

Basically for the line that contains title, extract the text between the tags, then quit (so you don't extract the 2nd <title>)

Add Items to Columns in a WPF ListView

Solution With Less XAML and More C#

If you define the ListView in XAML:

<ListView x:Name="listView"/>

Then you can add columns and populate it in C#:

public Window()
{
    // Initialize
    this.InitializeComponent();

    // Add columns
    var gridView = new GridView();
    this.listView.View = gridView;
    gridView.Columns.Add(new GridViewColumn { 
        Header = "Id", DisplayMemberBinding = new Binding("Id") });
    gridView.Columns.Add(new GridViewColumn { 
        Header = "Name", DisplayMemberBinding = new Binding("Name") });

    // Populate list
    this.listView.Items.Add(new MyItem { Id = 1, Name = "David" });
}

See definition of MyItem below.

Solution With More XAML and less C#

However, it's easier to define the columns in XAML (inside the ListView definition):

<ListView x:Name="listView">
    <ListView.View>
        <GridView>
            <GridViewColumn Header="Id" DisplayMemberBinding="{Binding Id}"/>
            <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}"/>
        </GridView>
    </ListView.View>
</ListView>

And then just populate the list in C#:

public Window()
{
    // Initialize
    this.InitializeComponent();

    // Populate list
    this.listView.Items.Add(new MyItem { Id = 1, Name = "David" });
}

See definition of MyItem below.

MyItem Definition

MyItem is defined like this:

public class MyItem
{
    public int Id { get; set; }

    public string Name { get; set; }
}

MySQL CREATE TABLE IF NOT EXISTS in PHPmyadmin import

If you really want to insert this record, remove the `abuse_id` field and the corresponding value from the INSERTstatement :

INSERT INTO  `abuses` (  `user_id` ,  `abuser_username` ,  `comment` ,  `reg_date` , `auction_id` ) 
VALUES ( 100020,  'artictundra', 'I placed a bid for it more than an hour ago. It is still active. I thought I was supposed to get an email after 15 minutes.', 1338052850, 108625 ) ;

Unable to begin a distributed transaction

OK, so services are started, there is an ethernet path between them, name resolution works, linked servers work, and you disabled transaction authentication.

My gut says firewall issue, but a few things come to mind...

  1. Are the machines in the same domain? (yeah, shouldn't matter with disabled authentication)
  2. Are firewalls running on the the machines? DTC can be a bit of pain for firewalls as it uses a range of ports, see http://support.microsoft.com/kb/306843 For the time being, I would disable firewalls for the sake of identifying the problem
  3. What does DTC ping say? http://www.microsoft.com/download/en/details.aspx?id=2868
  4. What account is the SQL Service running as ?

How to create a directive with a dynamic template in AngularJS?

i've used the $templateCache to accomplish something similar. i put several ng-templates in a single html file, which i reference using the directive's templateUrl. that ensures the html is available to the template cache. then i can simply select by id to get the ng-template i want.

template.html:

<script type="text/ng-template" id=“foo”>
foo
</script>

<script type="text/ng-template" id=“bar”>
bar
</script>

directive:

myapp.directive(‘foobardirective’, ['$compile', '$templateCache', function ($compile, $templateCache) {

    var getTemplate = function(data) {
        // use data to determine which template to use
        var templateid = 'foo';
        var template = $templateCache.get(templateid);
        return template;
    }

    return {
        templateUrl: 'views/partials/template.html',
        scope: {data: '='},
        restrict: 'E',
        link: function(scope, element) {
            var template = getTemplate(scope.data);

            element.html(template);
            $compile(element.contents())(scope);
        }
    };
}]);

Best way to check if column returns a null value (from database to .net application)

Just check for

if(table.rows[0][0] == null)
{
     //Whatever I want to do
}

or you could

if(t.Rows[0].IsNull(0))
{
     //Whatever I want to do
}

Play an audio file using jQuery when a button is clicked

$("#myAudioElement")[0].play();

It doesn't work with $("#myAudioElement").play() like you would expect. The official reason is that incorporating it into jQuery would add a play() method to every single element, which would cause unnecessary overhead. So instead you have to refer to it by its position in the array of DOM elements that you're retrieving with $("#myAudioElement"), aka 0.

This quote is from a bug that was submitted about it, which was closed as "feature/wontfix":

To do that we'd need to add a jQuery method name for each DOM element method name. And of course that method would do nothing for non-media elements so it doesn't seem like it would be worth the extra bytes it would take.

How to detect window.print() finish

Implementing window.onbeforeprint and window.onafterprint

The window.close() call after the window.print() is not working in Chrome v 78.0.3904.70

To approach this I'm using Adam's answer with a simple modification:

     function print() {
    (function () {
       let afterPrintCounter = !!window.chrome ? 0 : 1;
       let beforePrintCounter = !!window.chrome ? 0 : 1;
       var beforePrint = function () {
          beforePrintCounter++;
          if (beforePrintCounter === 2) {
             console.log('Functionality to run before printing.');
          }
       };
       var afterPrint = function () {
          afterPrintCounter++;
          if (afterPrintCounter === 2) {
             console.log('Functionality to run after printing.');
             //window.close();
          }
       };
       if (window.matchMedia) {
          var mediaQueryList = window.matchMedia('print');
          mediaQueryList.addListener(function (mql) {
             if (mql.matches) {
                beforePrint();
             } else {
                afterPrint();
             }
          });
       }
       window.onbeforeprint = beforePrint;
       window.onafterprint = afterPrint;
    }());
    //window.print(); //To print the page when it is loaded
 }

I'm calling it in here:

<body onload="print();">

This works for me. Note that I use a counter for both functions, so that I can handle this event in different browsers (fires twice in Chrome, and one time in Mozilla). For detecting the browser you can refer to this answer

How to dock "Tool Options" to "Toolbox"?

I'm using GIMP 2.8.1. I hope this will work for you:

Open the "Windows" menu and select "Single-Window Mode".

Simple ;)

Use of min and max functions in C++

Couldn't a C++ implementation targeted for processors with SSE instructions provide specializations of std::min and std::max for types float, double, and long double which do the equivalent of fminf, fmin, and fminl, respectively?

The specializations would provide better performance for floating-point types while the general template would handle non-floating-point types without attempting to coerce floating-point types into floating-point types that way the fmins and fmaxes would.

How to set a JVM TimeZone Properly

The accepted answer above:

-Duser.timezone="Europe/Sofia" 

Didn't work for me exactly. I only was able to successfully change my timezone when I didn't have quotes around the parameters:

-Duser.timezone=Europe/Sofia

Open local folder from link

Solution: Launching a Downloadable Link

The following works in all browsers, but as always there are caveats.

Background:

"URL Shortcuts" are OS dependent. The following solution is for MS Windows due to a lack of standards between environments.

If you require linux support for the solution below, please see this article.
* I have no connection to the article, YMMV.

URL shortcuts come in two forms:

  1. Files with .URL extensions are text based. Can be dynamically generated.

    [InternetShortcut]
    URL=file:///D:/

  2. Files with .LNK extension are binary. They can be generated dynamically, but require iShelLinkInterface implementer. This is complicated by default OS restrictions, which rightfully prevent an IIS process from reaching Shell.

.URL is the recommended solution, as dynamic generation is viable across Web Languages/Frameworks and allows for a KISS implementation.


Overview/Recap:

  1. Security restrictions will not allow you to open a path/launch explorer directly from the page (as stated by @Pekka).
  2. Sites hosted externally (not on your local computer) will not allow file:///... uri's under default security permissions.

Solution:

Provide a downloadable link (.URL or .LNK) to the resource. Browser behavior will be explained at end of post.

Option 1: Produce a .lnk file and save it to the server. Due to the binary nature of the .LNK file, this is not the recommended solution, but a pre-generated file should be viable.

Option 2: Produce a .url file and either save it to the server or dynamically generate it. In my situation, I am dynamically creating the .URL file.


Solution Details (.URL):

  1. Add .url to the available MIME types in your web server.

    For IIS open the site, choose MIME Types, and add the following:

    File name Extension= .url
    MIME type: application/internet-shortcut

    Per @cremax ... For Webkit Browsers like Chrome on Apache Servers add this code to .htaccess or http.config:

    SetEnvIf Request_URI ".url$" requested_url=url Header add Content-Disposition "attachment" env=requested_url

  2. The .url file is a text file formatted as follows (again, this can be dynamically generated).

    File Contents:

    [InternetShortcut]
    URL=file:///D:

  3. Provide a link to the script that generates the .url file, or to the file itself.

    If you've simply uploaded a .url file to your server, add the following to your HTML:

    <a href="URIShortcut.url">Round-About Linking</a>


Browser Dependent Behavior

Chrome: Download/Save file.url then open
In Chrome, this behavior can be augmented by choosing the "Always open files of this type" option.

FireFox: Download/Save file.url then open

Internet Explorer: Click “Open” and go straight to directory (no need to save shortcut)

Internet Explorer has the preferred behavior, but Chrome and Firefox are at least serviceable.

Catching multiple exception types in one catch block

In PHP >= 7.1 this is possible. See this answer.


If you can modify the exceptions, use this answer.

If you can't, you could try catching all with Exception and then check which exception was thrown with instanceof.

try
{
    /* something */
}
catch( Exception $e )
{
    if ($e instanceof AError OR $e instanceof BError) {
       // It's either an A or B exception.
    } else {
        // Keep throwing it.
        throw $e;
    }
}

But it would probably be better to use multiple catch blocks as described in aforementioned answer.

try
{
    /* something */
}
catch( AError $e )
{
   handler1( $e );
}
catch ( BError $b )
{
   handler2( $e );
}

How can I select all options of multi-select select box on click?

Try this:

$('#select_all').click(function() {
    $('#countries option').prop('selected', true);
});

And here's a live demo.

Overflow-x:hidden doesn't prevent content from overflowing in mobile browsers

try

html, body {
  overflow-x:hidden 
} 

instead of just

body {
  overflow-x:hidden 
}

Change background color of iframe issue

just building on what Chetabahana wrote, I found that adding a short delay to the JS function helped on a site I was working on. It meant that the function kicked in after the iframe loaded. You can play around with the delay.

var delayInMilliseconds = 500; // half a second

setTimeout(function() { 

   var iframe = document.getElementsByTagName('iframe')[0];
   iframe.style.background = 'white';
   iframe.contentWindow.document.body.style.backgroundColor = 'white';

}, delayInMilliseconds);

I hope this helps!

MySQL - force not to use cache for testing speed of query

Another alternative that only affects the current connection:

SET SESSION query_cache_type=0;

Using jquery to get element's position relative to viewport

The easiest way to determine the size and position of an element is to call its getBoundingClientRect() method. This method returns element positions in viewport coordinates. It expects no arguments and returns an object with properties left, right, top, and bottom. The left and top properties give the X and Y coordinates of the upper-left corner of the element and the right and bottom properties give the coordinates of the lower-right corner.

element.getBoundingClientRect(); // Get position in viewport coordinates

Supported everywhere.

Android: Force EditText to remove focus?

try to use this one on your view it worked for me:

<View
    android:id="@+id/fucused"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:focusable="true"
    android:focusableInTouchMode="true"/>

IF EXIST C:\directory\ goto a else goto b problems windows XP batch files

@echo off

:START
rmdir temporary
cls
IF EXIST "temporary\." (echo The temporary directory exists) else echo The temporary directory doesn't exist
echo.
dir temporary /A:D
pause

echo.
echo.
echo Note the directory is not found
echo.
echo Press any key to make a temporary directory, cls, and test again
pause

Mkdir temporary
cls
IF EXIST "temporary\." (echo The temporary directory exists) else echo The temporary directory doesn't exist
echo.
dir temporary /A:D
pause
echo.
echo press any key to goto START and remove temporary directory 
pause 

goto START

Android: show/hide a view using an animation

If you only want to animate the height of a view (from say 0 to a certain number) you could implement your own animation:

final View v = getTheViewToAnimateHere();
Animation anim=new Animation(){
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        super.applyTransformation(interpolatedTime, t);
        // Do relevant calculations here using the interpolatedTime that runs from 0 to 1
        v.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, (int)(30*interpolatedTime)));
    }};
anim.setDuration(500);
v.startAnimation(anim);

How to check if a table exists in MS Access for vb macros

Setting a reference to the Microsoft Access 12.0 Object Library allows us to test if a table exists using DCount.

Public Function ifTableExists(tblName As String) As Boolean

    If DCount("[Name]", "MSysObjects", "[Name] = '" & tblName & "'") = 1 Then

        ifTableExists = True

    End If

End Function

Change background of LinearLayout in Android

u just used attribute

  • android:background="#ColorCode" for colors

    if your image save in drawable folder then used :-

  • android:background="@drawable/ImageName" for image setting

SQL Order By Count

Q. List the name of each show, and the number of different times it has been held. List the show which has been held most often first.

event_id show_id event_name judge_id
0101    01  Dressage        01
0102    01  Jumping         02
0103    01  Led in          01
0201    02  Led in          02
0301    03  Led in          01
0401    04  Dressage        04
0501    05  Dressage        01
0502    05  Flag and Pole   02

Ans:

select event_name, count(show_id) as held_times from event 
group by event_name 
order by count(show_id) desc

Permission denied at hdfs

I solved this problem temporary by disabling the dfs permission.By adding below property code to conf/hdfs-site.xml

<property>
  <name>dfs.permissions</name>
  <value>false</value>
</property>

Fatal error: Class 'ZipArchive' not found in

I faced this issue on GCP while deploying wordpress in the App Engine Standard environment. This solved it :

sudo apt-get install php7.2-zip

PHP Function Comments

You must check this: Docblock Comment standards

http://pear.php.net/manual/en/standards.sample.php

INNER JOIN in UPDATE sql for DB2

Joins in update statements are non-standard and not supported by all vendors. What you're trying to do can be accomplished with a sub-select:

update
  file1
set
  firstfield = (select 'stuff' concat something from file2 where substr(file1.field1, 10, 20) = substr(file2.xxx,1,10) )
where
  file1.foo like 'BLAH%'

Why is using a wild card with a Java import statement bad?

In DDD book

In whatever development technology the implementation will be based on, look for ways of minimizing the work of refactoring MODULES . In Java, there is no escape from importing into individual classes, but you can at least import entire packages at a time, reflecting the intention that packages are highly cohesive units while simultaneously reducing the effort of changing package names.

And if it clutters local namespace its not your fault - blame the size of the package.

Changing the selected option of an HTML Select element

I want to change the select element's selected option's both value & textContent (what we see) to 'Mango'.

Simplest code that worked is below:

var newValue1 = 'Mango'

var selectElement = document.getElementById('myselectid');
selectElement.options[selectElement.selectedIndex].value = newValue1;
selectElement.options[selectElement.selectedIndex].textContent = newValue1;

Hope that helps someone. Best of luck.
Up vote if this helped you.

What are the differences between a HashMap and a Hashtable in Java?

Old and classic topic, just want to add this helpful blog that explains this:

http://blog.manishchhabra.com/2012/08/the-5-main-differences-betwen-hashmap-and-hashtable/

Blog by Manish Chhabra

The 5 main differences betwen HashMap and Hashtable

HashMap and Hashtable both implement java.util.Map interface but there are some differences that Java developers must understand to write more efficient code. As of the Java 2 platform v1.2, Hashtable class was retrofitted to implement the Map interface, making it a member of the Java Collections Framework.

  1. One of the major differences between HashMap and Hashtable is that HashMap is non-synchronized whereas Hashtable is synchronized, which means Hashtable is thread-safe and can be shared between multiple threads but HashMap cannot be shared between multiple threads without proper synchronization. Java 5 introduced ConcurrentHashMap which is an alternative of Hashtable and provides better scalability than Hashtable in Java.Synchronized means only one thread can modify a hash table at one point of time. Basically, it means that any thread before performing an update on a hashtable will have to acquire a lock on the object while others will wait for lock to be released.

  2. The HashMap class is roughly equivalent to Hashtable, except that it permits nulls. (HashMap allows null values as key and value whereas Hashtable doesn’t allow nulls).

  3. The third significant difference between HashMap vs Hashtable is that Iterator in the HashMap is a fail-fast iterator while the enumerator for the Hashtable is not and throw ConcurrentModificationException if any other Thread modifies the map structurally by adding or removing any element except Iterator’s own remove() method. But this is not a guaranteed behavior and will be done by JVM on best effort. This is also an important difference between Enumeration and Iterator in Java.

  4. One more notable difference between Hashtable and HashMap is that because of thread-safety and synchronization Hashtable is much slower than HashMap if used in Single threaded environment. So if you don’t need synchronization and HashMap is only used by one thread, it out perform Hashtable in Java.

  5. HashMap does not guarantee that the order of the map will remain constant over time.

Note that HashMap can be synchronized by

Map m = Collections.synchronizedMap(hashMap);

In Summary there are significant differences between Hashtable and HashMap in Java e.g. thread-safety and speed and based upon that only use Hashtable if you absolutely need thread-safety, if you are running Java 5 consider using ConcurrentHashMap in Java.

subtract time from date - moment js

There is a simple function subtract which moment library gives us to subtract time from some time. Using it is also very simple.

moment(Date.now()).subtract(7, 'days'); // This will subtract 7 days from current time
moment(Date.now()).subtract(3, 'd'); // This will subtract 3 days from current time

//You can do this for days, years, months, hours, minutes, seconds
//You can also subtract multiple things simulatneously

//You can chain it like this.
moment(Date.now()).subtract(3, 'd').subtract(5. 'h'); // This will subtract 3 days and 5 hours from current time

//You can also use it as object literal
moment(Date.now()).subtract({days:3, hours:5}); // This will subtract 3 days and 5 hours from current time

Hope this helps!

sort json object in javascript

In some ways, your question seems very legitimate, but I still might label it an XY problem. I'm guessing the end result is that you want to display the sorted values in some way? As Bergi said in the comments, you can never quite rely on Javascript objects ( {i_am: "an_object"} ) to show their properties in any particular order.

For the displaying order, I might suggest you take each key of the object (ie, i_am) and sort them into an ordered array. Then, use that array when retrieving elements of your object to display. Pseudocode:

var keys = [...]
var sortedKeys = [...]
for (var i = 0; i < sortedKeys.length; i++) {
  var key = sortedKeys[i];
  addObjectToTable(json[key]);
}

SQL SELECT from multiple tables

select p.pid, p.cid, c1.name,c2.name
from product p
left outer join customer1 c1 on c1.cid=p.cid
left outer join customer2 c2 on c2.cid=p.cid

OpenSSL and error in reading openssl.conf file

The problem here is that there ISN'T an openssl.cnf file given with the GnuWin32 openssl stuff. You have to create it. You can find out HOW to create an openssl.cnf file by going here:

http://www.flatmtn.com/article/setting-ssl-certificates-apache

Where it lays it all out for you on how to do it.

PLEASE NOTE: The openssl command given with the backslash at the end is for UNIX. For Windows : 1)Remove the backslash, and 2)Move the second line up so it is at the end of the first line. (So you get just one command.)

ALSO: It is VERY important to read through the comments. There are some changes you might want to make based upon them.

java - path to trustStore - set property doesn't work?

You have a typo - it is trustStore.

Apart from setting the variables with System.setProperty(..), you can also use

-Djavax.net.ssl.keyStore=path/to/keystore.jks