Programs & Examples On #Lvalue to rvalue

android asynctask sending callbacks to ui

IN completion to above answers, you can also customize your fallbacks for each async call you do, so that each call to the generic ASYNC method will populate different data, depending on the onTaskDone stuff you put there.

  Main.FragmentCallback FC= new  Main.FragmentCallback(){
            @Override
            public void onTaskDone(String results) {

                localText.setText(results); //example TextView
            }
        };

new API_CALL(this.getApplicationContext(), "GET",FC).execute("&Books=" + Main.Books + "&args=" + profile_id);

Remind: I used interface on the main activity thats where "Main" comes, like this:

public interface FragmentCallback {
    public void onTaskDone(String results);


}

My API post execute looks like this:

  @Override
    protected void onPostExecute(String results) {

        Log.i("TASK Result", results);
        mFragmentCallback.onTaskDone(results);

    }

The API constructor looks like this:

 class  API_CALL extends AsyncTask<String,Void,String>  {

    private Main.FragmentCallback mFragmentCallback;
    private Context act;
    private String method;


    public API_CALL(Context ctx, String api_method,Main.FragmentCallback fragmentCallback) {
        act=ctx;
        method=api_method;
        mFragmentCallback = fragmentCallback;


    }

How can I use the python HTMLParser library to extract data from a specific div tag?

Have You tried BeautifulSoup ?

from bs4 import BeautifulSoup
soup = BeautifulSoup('<div id="remository">20</div>')
tag=soup.div
print(tag.string)

This gives You 20 on output.

Overriding !important style

If you want to update / add single style in DOM Element style attribute you can use this function:

function setCssTextStyle(el, style, value) {
  var result = el.style.cssText.match(new RegExp("(?:[;\\s]|^)(" +
      style.replace("-", "\\-") + "\\s*:(.*?)(;|$))")),
    idx;
  if (result) {
    idx = result.index + result[0].indexOf(result[1]);
    el.style.cssText = el.style.cssText.substring(0, idx) +
      style + ": " + value + ";" +
      el.style.cssText.substring(idx + result[1].length);
  } else {
    el.style.cssText += " " + style + ": " + value + ";";
  }
}

style.cssText is supported for all major browsers.

Use case example:

var elem = document.getElementById("elementId");
setCssTextStyle(elem, "margin-top", "10px !important");

Here is link to demo

How do I specify local .gem files in my Gemfile?

I would unpack your gem in the application vendor folder

gem unpack your.gem --target /path_to_app/vendor/gems/

Then add the path on the Gemfile to link unpacked gem.

gem 'your', '2.0.1', :path => 'vendor/gems/your'

How to get min, seconds and milliseconds from datetime.now() in python?

Sorry to open an old thread but I'm posting just in case it helps someone. This seems to be the easiest way to do this in Python 3.

from datetime import datetime

Date = str(datetime.now())[:10]
Hour = str(datetime.now())[11:13]
Minute = str(datetime.now())[14:16]
Second = str(datetime.now())[17:19]
Millisecond = str(datetime.now())[20:]

If you need the values as a number just cast them as an int e.g

Hour = int(str(datetime.now())[11:13])

How to run a script file remotely using SSH

I don't know if it's possible to run it just like that.

I usually first copy it with scp and then log in to run it.

scp foo.sh user@host:~
ssh user@host
./foo.sh

I'm getting Key error in python

For dict, just use

if key in dict

and don't use searching in key list

if key in dict.keys()

The latter will be more time-consuming.

Div with margin-left and width:100% overflowing on the right side

If some other portion of your layout is influencing the div width you can set width:auto and the div (which is a block element) will fill the space

<div style="width:auto">
    <div style="margin-left:45px;width:auto">
        <asp:TextBox ID="txtTitle" runat="server" Width="100%"></asp:TextBox><br />
    </div>
</div>

If that's still not working we may need to see more of your layout HTML/CSS

Base64 Java encode and decode a string

The following is a good solution -

import android.util.Base64;

String converted = Base64.encodeToString(toConvert.toString().getBytes(), Base64.DEFAULT);

String stringFromBase = new String(Base64.decode(converted, Base64.DEFAULT));

That's it. A single line encoding and decoding.

How to convert text to binary code in JavaScript?

What you should do is convert every char using charCodeAt function to get the Ascii Code in decimal. Then you can convert it to Binary value using toString(2):

HTML:

<input id="ti1" value ="TEST"/>
<input id="ti2"/>
<button onClick="convert();">Convert!</button>

JS:

function convert() {
  var output = document.getElementById("ti2");
  var input = document.getElementById("ti1").value;
  output.value = "";
  for (var i = 0; i < input.length; i++) {
      output.value += input[i].charCodeAt(0).toString(2) + " ";
  }
}

And here's a fiddle: http://jsfiddle.net/fA24Y/1/

Processing Symbol Files in Xcode

Add SDK version correspond to your iPhone iOS, eg: iOS 10.3

path:

/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport


It's downloading. When it's finished, it's OK. As shown in the figure:

enter image description here

How to install the JDK on Ubuntu Linux

If you want to install Oracle JDK, you can use this automated script that does all the work for you.

There are detailed instructions how to use it on the author's blog.

Populating a dictionary using for loops (python)

dicts = {}
keys = range(4)
values = ["Hi", "I", "am", "John"]
for i in keys:
        dicts[i] = values[i]
print(dicts)

alternatively

In [7]: dict(list(enumerate(values)))
Out[7]: {0: 'Hi', 1: 'I', 2: 'am', 3: 'John'}

numpy matrix vector multiplication

Simplest solution

Use numpy.dot or a.dot(b). See the documentation here.

>>> a = np.array([[ 5, 1 ,3], 
                  [ 1, 1 ,1], 
                  [ 1, 2 ,1]])
>>> b = np.array([1, 2, 3])
>>> print a.dot(b)
array([16, 6, 8])

This occurs because numpy arrays are not matrices, and the standard operations *, +, -, / work element-wise on arrays. Instead, you could try using numpy.matrix, and * will be treated like matrix multiplication.


Other Solutions

Also know there are other options:

  • As noted below, if using python3.5+ the @ operator works as you'd expect:

    >>> print(a @ b)
    array([16, 6, 8])
    
  • If you want overkill, you can use numpy.einsum. The documentation will give you a flavor for how it works, but honestly, I didn't fully understand how to use it until reading this answer and just playing around with it on my own.

    >>> np.einsum('ji,i->j', a, b)
    array([16, 6, 8])
    
  • As of mid 2016 (numpy 1.10.1), you can try the experimental numpy.matmul, which works like numpy.dot with two major exceptions: no scalar multiplication but it works with stacks of matrices.

    >>> np.matmul(a, b)
    array([16, 6, 8])
    
  • numpy.inner functions the same way as numpy.dot for matrix-vector multiplication but behaves differently for matrix-matrix and tensor multiplication (see Wikipedia regarding the differences between the inner product and dot product in general or see this SO answer regarding numpy's implementations).

    >>> np.inner(a, b)
    array([16, 6, 8])
    
    # Beware using for matrix-matrix multiplication though!
    >>> b = a.T
    >>> np.dot(a, b)
    array([[35,  9, 10],
           [ 9,  3,  4],
           [10,  4,  6]])
    >>> np.inner(a, b) 
    array([[29, 12, 19],
           [ 7,  4,  5],
           [ 8,  5,  6]])
    

Rarer options for edge cases

  • If you have tensors (arrays of dimension greater than or equal to one), you can use numpy.tensordot with the optional argument axes=1:

    >>> np.tensordot(a, b, axes=1)
    array([16,  6,  8])
    
  • Don't use numpy.vdot if you have a matrix of complex numbers, as the matrix will be flattened to a 1D array, then it will try to find the complex conjugate dot product between your flattened matrix and vector (which will fail due to a size mismatch n*m vs n).

Searching a string in eclipse workspace

Goto Search->File

You will get an window, you can give either simple search text or regx pattern. Once you enter your search keyword click Search and make sure that Scope is Workspace.

You may use this for Replace as well.

How do I bind Twitter Bootstrap tooltips to dynamically created elements?

Try this one:

$('body').tooltip({
    selector: '[rel=tooltip]'
});

Can I use DIV class and ID together in CSS?

Of course you can.

Your HTML there is just fine. To style the elements with css you can use the following approaches:

#y {
    ...
}

.x {
    ...
}

#y.x {
    ...
}

Also you can add as many classes as you wish to your element

<div id="id" class="classA classB classC ...">
</div>

And you can style that element using a selector with any combination of the classes and id. For example:

#id.classA.classB.classC {
     ...
}

#id.classC {
}

'React' must be in scope when using JSX react/react-in-jsx-scope?

Follow as in picture for removing that lint error and adding automatic fix by addin g--fix in package.json

enter image description here

Open the terminal in visual studio?

In Visual Studio 2019- Tools > Command Line > Developer Command Prompt.enter image description here

How to open link in new tab on html?

Use one of these as per your requirements.

Open the linked document in a new window or tab:

 <a href="xyz.html" target="_blank"> Link </a>

Open the linked document in the same frame as it was clicked (this is default):

 <a href="xyz.html" target="_self"> Link </a>

Open the linked document in the parent frame:

 <a href="xyz.html" target="_parent"> Link </a>

Open the linked document in the full body of the window:

 <a href="xyz.html" target="_top"> Link </a>

Open the linked document in a named frame:

 <a href="xyz.html" target="framename"> Link </a>

See MDN

Generator expressions vs. list comprehensions

I'm using the Hadoop Mincemeat module. I think this is a great example to take a note of:

import mincemeat

def mapfn(k,v):
    for w in v:
        yield 'sum',w
        #yield 'count',1


def reducefn(k,v): 
    r1=sum(v)
    r2=len(v)
    print r2
    m=r1/r2
    std=0
    for i in range(r2):
       std+=pow(abs(v[i]-m),2)  
    res=pow((std/r2),0.5)
    return r1,r2,res

Here the generator gets numbers out of a text file (as big as 15GB) and applies simple math on those numbers using Hadoop's map-reduce. If I had not used the yield function, but instead a list comprehension, it would have taken a much longer time calculating the sums and average (not to mention the space complexity).

Hadoop is a great example for using all the advantages of Generators.

Double free or corruption after queue::push

Let's talk about copying objects in C++.

Test t;, calls the default constructor, which allocates a new array of integers. This is fine, and your expected behavior.

Trouble comes when you push t into your queue using q.push(t). If you're familiar with Java, C#, or almost any other object-oriented language, you might expect the object you created earler to be added to the queue, but C++ doesn't work that way.

When we take a look at std::queue::push method, we see that the element that gets added to the queue is "initialized to a copy of x." It's actually a brand new object that uses the copy constructor to duplicate every member of your original Test object to make a new Test.

Your C++ compiler generates a copy constructor for you by default! That's pretty handy, but causes problems with pointer members. In your example, remember that int *myArray is just a memory address; when the value of myArray is copied from the old object to the new one, you'll now have two objects pointing to the same array in memory. This isn't intrinsically bad, but the destructor will then try to delete the same array twice, hence the "double free or corruption" runtime error.

How do I fix it?

The first step is to implement a copy constructor, which can safely copy the data from one object to another. For simplicity, it could look something like this:

Test(const Test& other){
    myArray = new int[10];
    memcpy( myArray, other.myArray, 10 );
}

Now when you're copying Test objects, a new array will be allocated for the new object, and the values of the array will be copied as well.

We're not completely out trouble yet, though. There's another method that the compiler generates for you that could lead to similar problems - assignment. The difference is that with assignment, we already have an existing object whose memory needs to be managed appropriately. Here's a basic assignment operator implementation:

Test& operator= (const Test& other){
    if (this != &other) {
        memcpy( myArray, other.myArray, 10 );
    }
    return *this;
}

The important part here is that we're copying the data from the other array into this object's array, keeping each object's memory separate. We also have a check for self-assignment; otherwise, we'd be copying from ourselves to ourselves, which may throw an error (not sure what it's supposed to do). If we were deleting and allocating more memory, the self-assignment check prevents us from deleting memory from which we need to copy.

Javascript getElementById based on a partial string

Given that what you want is to determine the full id of the element based upon just the prefix, you're going to have to do a search of the entire DOM (or at least, a search of an entire subtree if you know of some element that is always guaranteed to contain your target element). You can do this with something like:

function findChildWithIdLike(node, prefix) {
    if (node && node.id && node.id.indexOf(prefix) == 0) {
        //match found
        return node;
    }

    //no match, check child nodes
    for (var index = 0; index < node.childNodes.length; index++) {
        var child = node.childNodes[index];
        var childResult = findChildWithIdLike(child, prefix);
        if (childResult) {
            return childResult;
        }
    }
};

Here is an example: http://jsfiddle.net/xwqKh/

Be aware that dynamic element ids like the ones you are working with are typically used to guarantee uniqueness of element ids on a single page. Meaning that it is likely that there are multiple elements that share the same prefix. Probably you want to find them all.

If you want to find all of the elements that have a given prefix, instead of just the first one, you can use something like what is demonstrated here: http://jsfiddle.net/xwqKh/1/

How to directly move camera to current location in Google Maps Android API v2?

The above answer is not according to what Google Doc Referred for Location Tracking in Google api v2.

I just followed the official tutorial and ended up with this class that is fetching the current location and centring the map on it as soon as i get that.

you can extend this class to have LocationReciever to have periodic Location Update. I just executed this code on api level 7

http://developer.android.com/training/location/retrieve-current.html

Here it goes.

import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;


public class MainActivity extends FragmentActivity implements 
    GooglePlayServicesClient.ConnectionCallbacks, 
    GooglePlayServicesClient.OnConnectionFailedListener{

private SupportMapFragment mapFragment;
private GoogleMap map;
private LocationClient mLocationClient;
/*
 * Define a request code to send to Google Play services
 * This code is returned in Activity.onActivityResult
 */
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;

// Define a DialogFragment that displays the error dialog
public static class ErrorDialogFragment extends DialogFragment {

    // Global field to contain the error dialog
    private Dialog mDialog;

    // Default constructor. Sets the dialog field to null
    public ErrorDialogFragment() {
        super();
        mDialog = null;
    }

    // Set the dialog to display
    public void setDialog(Dialog dialog) {
        mDialog = dialog;
    }

    // Return a Dialog to the DialogFragment.
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        return mDialog;
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_activity);

    mLocationClient = new LocationClient(this, this, this);

    mapFragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));
    map = mapFragment.getMap();

    map.setMyLocationEnabled(true);

}

/*
 * Called when the Activity becomes visible.
 */
@Override
protected void onStart() {
    super.onStart();
    // Connect the client.
    if(isGooglePlayServicesAvailable()){
        mLocationClient.connect();
    }

}

/*
 * Called when the Activity is no longer visible.
 */
@Override
protected void onStop() {
    // Disconnecting the client invalidates it.
    mLocationClient.disconnect();
    super.onStop();
}

/*
 * Handle results returned to the FragmentActivity
 * by Google Play services
 */
@Override
protected void onActivityResult(
                int requestCode, int resultCode, Intent data) {
    // Decide what to do based on the original request code
    switch (requestCode) {

        case CONNECTION_FAILURE_RESOLUTION_REQUEST:
            /*
             * If the result code is Activity.RESULT_OK, try
             * to connect again
             */
            switch (resultCode) {
                case Activity.RESULT_OK:
                    mLocationClient.connect();
                    break;
            }

    }
}

private boolean isGooglePlayServicesAvailable() {
    // Check that Google Play services is available
    int resultCode =  GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
    // If Google Play services is available
    if (ConnectionResult.SUCCESS == resultCode) {
        // In debug mode, log the status
        Log.d("Location Updates", "Google Play services is available.");
        return true;
    } else {
        // Get the error dialog from Google Play services
        Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog( resultCode,
                                                                                                              this,
                                                                                                              CONNECTION_FAILURE_RESOLUTION_REQUEST);

        // If Google Play services can provide an error dialog
        if (errorDialog != null) {
            // Create a new DialogFragment for the error dialog
            ErrorDialogFragment errorFragment = new ErrorDialogFragment();
            errorFragment.setDialog(errorDialog);
            errorFragment.show(getSupportFragmentManager(), "Location Updates");
        }

        return false;
    }
}

/*
 * Called by Location Services when the request to connect the
 * client finishes successfully. At this point, you can
 * request the current location or start periodic updates
 */
@Override
public void onConnected(Bundle dataBundle) {
    // Display the connection status
    Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
    Location location = mLocationClient.getLastLocation();
    LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 17);
    map.animateCamera(cameraUpdate);
}

/*
 * Called by Location Services if the connection to the
 * location client drops because of an error.
 */
@Override
public void onDisconnected() {
    // Display the connection status
    Toast.makeText(this, "Disconnected. Please re-connect.",
            Toast.LENGTH_SHORT).show();
}

/*
 * Called by Location Services if the attempt to
 * Location Services fails.
 */
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
    /*
     * Google Play services can resolve some errors it detects.
     * If the error has a resolution, try sending an Intent to
     * start a Google Play services activity that can resolve
     * error.
     */
    if (connectionResult.hasResolution()) {
        try {
            // Start an Activity that tries to resolve the error
            connectionResult.startResolutionForResult(
                    this,
                    CONNECTION_FAILURE_RESOLUTION_REQUEST);
            /*
            * Thrown if Google Play services canceled the original
            * PendingIntent
            */
        } catch (IntentSender.SendIntentException e) {
            // Log the error
            e.printStackTrace();
        }
    } else {
       Toast.makeText(getApplicationContext(), "Sorry. Location services not available to you", Toast.LENGTH_LONG).show();
    }
}

}

Get first word of string

I'm surprised this method hasn't been mentioned: "Some string".split(' ').shift()


To answer the question directly:

let firstWords = []
let str = "Hello m|sss sss|mmm ss";
const codeLines = str.split("|");

for (var i = 0; i < codeLines.length; i++) {
  const first = codeLines[i].split(' ').shift()
  firstWords.push(first)
}

scrollTop jquery, scrolling to div with id?

try this

    $('#div_id').animate({scrollTop:0}, '500', 'swing');

Writing Unicode text to a text file?

In case of writing in python3

>>> a = u'bats\u00E0'
>>> print a
batsà
>>> f = open("/tmp/test", "w")
>>> f.write(a)
>>> f.close()
>>> data = open("/tmp/test").read()
>>> data
'batsà'

In case of writing in python2:

>>> a = u'bats\u00E0'
>>> f = open("/tmp/test", "w")
>>> f.write(a)

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe0' in position 4: ordinal not in range(128)

To avoid this error you would have to encode it to bytes using codecs "utf-8" like this:

>>> f.write(a.encode("utf-8"))
>>> f.close()

and decode the data while reading using the codecs "utf-8":

>>> data = open("/tmp/test").read()
>>> data.decode("utf-8")
u'bats\xe0'

And also if you try to execute print on this string it will automatically decode using the "utf-8" codecs like this

>>> print a
batsà

Return True, False and None in Python

It's impossible to say without seeing your actual code. Likely the reason is a code path through your function that doesn't execute a return statement. When the code goes down that path, the function ends with no value returned, and so returns None.

Updated: It sounds like your code looks like this:

def b(self, p, data): 
    current = p 
    if current.data == data: 
        return True 
    elif current.data == 1:
        return False 
    else: 
        self.b(current.next, data)

That else clause is your None path. You need to return the value that the recursive call returns:

    else:
        return self.b(current.next, data)

BTW: using recursion for iterative programs like this is not a good idea in Python. Use iteration instead. Also, you have no clear termination condition.

Index was out of range. Must be non-negative and less than the size of the collection parameter name:index

what this means ? is there any problem in my code

It means that you are accessing a location or index which is not present in collection.

To find this, Make sure your Gridview has 5 columns as you are using it's 5th column by this line

dataGridView1.Columns[4].Name = "Amount";

Here is the image which shows the elements of an array. So if your gridview has less column then the (index + 1) by which you are accessing it, then this exception arises.

enter image description here

How should I print types like off_t and size_t?

As I recall, the only portable way to do it, is to cast the result to "unsigned long int" and use %lu.

printf("sizeof(int) = %lu", (unsigned long) sizeof(int));

Find Locked Table in SQL Server

You can use sp_lock (and sp_lock2), but in SQL Server 2005 onwards this is being deprecated in favour of querying sys.dm_tran_locks:

select  
    object_name(p.object_id) as TableName, 
    resource_type, resource_description
from
    sys.dm_tran_locks l
    join sys.partitions p on l.resource_associated_entity_id = p.hobt_id

SQL Data Reader - handling Null column values

One way to do it is to check for db nulls:

employee.FirstName = (sqlreader.IsDBNull(indexFirstName) 
    ? ""
    : sqlreader.GetString(indexFirstName));

Given a DateTime object, how do I get an ISO 8601 date in string format?

Note to readers: Several commenters have pointed out some problems in this answer (related particularly to the first suggestion). Refer to the comments section for more information.

DateTime.UtcNow.ToString("yyyy-MM-ddTHH\\:mm\\:ss.fffffffzzz");

This gives you a date similar to 2008-09-22T13:57:31.2311892-04:00.

Another way is:

DateTime.UtcNow.ToString("o");

which gives you 2008-09-22T14:01:54.9571247Z

To get the specified format, you can use:

DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ")

DateTime Formatting Options

Android SQLite SELECT Query

Try trimming the string to make sure there is no extra white space:

Cursor c = db.rawQuery("SELECT * FROM tbl1 WHERE TRIM(name) = '"+name.trim()+"'", null);

Also use c.moveToFirst() like @thinksteep mentioned.


This is a complete code for select statements.

SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery("SELECT column1,column2,column3 FROM table ", null);
if (c.moveToFirst()){
    do {
        // Passing values 
        String column1 = c.getString(0);
        String column2 = c.getString(1);
        String column3 = c.getString(2); 
        // Do something Here with values
    } while(c.moveToNext());
}
c.close();
db.close();

Edit line thickness of CSS 'underline' attribute

Another way to do this is using ":after" (pseudo-element) on the element you want to underline.

h2{
  position:relative;
  display:inline-block;
  font-weight:700;
  font-family:arial,sans-serif;
  text-transform:uppercase;
  font-size:3em;
}
h2:after{
  content:"";
  position:absolute;
  left:0;
  bottom:0;
  right:0;
  margin:auto;
  background:#000;
  height:1px;

}

Deactivate or remove the scrollbar on HTML

Meder Omuraliev suggested to use an event handler and set scrollTo(0,0). This is an example for Wassim-azirar. Bringing it all together, I assume this is the final solution.

We have 3 problems: the scrollbar, scrolling with mouse, and keyboard. This hides the scrollbar:

       html, body{overflow:hidden;}

Unfortunally, you can still scroll with the keyboard: To prevent this, we can:

    function keydownHandler(e) {
var evt = e ? e:event;
  var keyCode = evt.keyCode;

  if (keyCode==38 || keyCode==39 || keyCode==40 || keyCode==37){ //arrow keys
e.preventDefault()
scrollTo(0,0);
}
}

document.onkeydown=keydownHandler;

The scrolling with the mouse just naturally doesn't work after this code, so we have prevented the scrolling.

For example: https://jsfiddle.net/aL7pes70/1/

How to "add existing frameworks" in Xcode 4?

  1. In the project navigator, select your project.

  2. Select your target.

  3. Select the "Build Phases" tab.

  4. expander. Click the + button.

  5. Select your framework.

  6. (optional) Drag and drop the added framework to the "Frameworks" group.

    enter image description here

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

Try to create a file using the code, so you will get to know the path of the file where the system create

File test=new File("check.txt");
if (test.createNewFile()) {
    System.out.println("File created: " + test.getName());
  }

Register DLL file on Windows Server 2008 R2

You need the full path to the regsvr32 so %windir$\system32\regsvr32 <*.dll>

How to select label for="XYZ" in CSS?

If the label immediately follows a specified input element:

input#example + label { ... }
input:checked + label { ... }

There can be only one auto column

Note also that "key" does not necessarily mean primary key. Something like this will work:

CREATE TABLE book (
    isbn             BIGINT NOT NULL PRIMARY KEY,
    id               INT    NOT NULL AUTO_INCREMENT,
    accepted_terms   BIT(1) NOT NULL,
    accepted_privacy BIT(1) NOT NULL,
    INDEX(id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

This is a contrived example and probably not the best idea, but it can be very useful in certain cases.

Threading Example in Android

One of Androids powerful feature is the AsyncTask class.

To work with it, you have to first extend it and override doInBackground(...). doInBackground automatically executes on a worker thread, and you can add some listeners on the UI Thread to get notified about status update, those functions are called: onPreExecute(), onPostExecute() and onProgressUpdate()

You can find a example here.

Refer to below post for other alternatives:

Handler vs AsyncTask vs Thread

Choose File Dialog

I have implemented the Samsung File Selector Dialog, it provides the ability to open, save file, file extension filter, and create new directory in the same dialog I think it worth trying Here is the Link you have to log in to Samsung developer site to view the solution

How to install python3 version of package via pip on Ubuntu?

  1. You should install ALL dependencies:

    sudo apt-get install build-essential python3-dev python3-setuptools python3-numpy python3-scipy libatlas-dev libatlas3gf-base

  2. Install pip3(if you have installed, please look step 3):

    sudo apt-get install python3-pip

  3. Iinstall scikit-learn by pip3

    pip3 install -U scikit-learn

  4. Open your terminal and entry python3 environment, type import sklearn to check it.

Gook Luck!

What should main() return in C and C++?

Here is a small demonstration of the usage of return codes...

When using the various tools that the Linux terminal provides one can use the return code for example for error handling after the process has been completed. Imagine that the following text file myfile is present:

This is some example in order to check how grep works.

When you execute the grep command a process is created. Once it is through (and didn't break) it returns some code between 0 and 255. For example:

$ grep order myfile

If you do

$ echo $?
$ 0

you will get a 0. Why? Because grep found a match and returned an exit code 0, which is the usual value for exiting with a success. Let's check it out again but with something that is not inside our text file and thus no match will be found:

$ grep foo myfile
$ echo $?
$ 1

Since grep failed to match the token "foo" with the content of our file the return code is 1 (this is the usual case when a failure occurs but as stated above you have plenty of values to choose from).

Now the following bash script (simply type it in a Linux terminal) although very basic should give some idea of error handling:

$ grep foo myfile
$ CHECK=$?
$ [ $CHECK -eq 0] && echo 'Match found'
$ [ $CHECK -ne 0] && echo 'No match was found'
$ No match was found

After the second line nothing is printed to the terminal since "foo" made grep return 1 and we check if the return code of grep was equal to 0. The second conditional statement echoes its message in the last line since it is true due to CHECK == 1.

As you can see if you are calling this and that process it is sometimes essential to see what it has returned (by the return value of main()).

find all subsets that sum to a particular value

def total_subsets_matching_sum(numbers, sum):
    array = [1] + [0] * (sum)
    for current_number in numbers:
        for num in xrange(sum - current_number, -1, -1):
            if array[num]:
                array[num + current_number] += array[num]
    return array[sum]

assert(total_subsets_matching_sum(range(1, 10), 9)       == 8)
assert(total_subsets_matching_sum({1, 3, 2, 5, 4, 9}, 9) == 4)

Explanation

This is one of the classic problems. The idea is to find the number of possible sums with the current number. And its true that, there is exactly one way to bring sum to 0. At the beginning, we have only one number. We start from our target (variable Maximum in the solution) and subtract that number. If it is possible to get a sum of that number (array element corresponding to that number is not zero) then add it to the array element corresponding to the current number. The program would be easier to understand this way

for current_number in numbers:
    for num in xrange(sum, current_number - 1, -1):
        if array[num - current_number]:
            array[num] += array[num - current_number]

When the number is 1, there is only one way in which you can come up with the sum of 1 (1-1 becomes 0 and the element corresponding to 0 is 1). So the array would be like this (remember element zero will have 1)

[1, 1, 0, 0, 0, 0, 0, 0, 0, 0]

Now, the second number is 2. We start subtracting 2 from 9 and its not valid (since array element of 7 is zero we skip that) we keep doing this till 3. When its 3, 3 - 2 is 1 and the array element corresponding to 1 is 1 and we add it to the array element of 3. and when its 2, 2 - 2 becomes 0 and we the value corresponding to 0 to array element of 2. After this iteration the array looks like this

[1, 1, 1, 1, 0, 0, 0, 0, 0, 0]

We keep doing this till we process all the numbers and the array after every iteration looks like this

[1, 1, 0, 0, 0, 0, 0, 0, 0, 0]
[1, 1, 1, 1, 0, 0, 0, 0, 0, 0]
[1, 1, 1, 2, 1, 1, 1, 0, 0, 0]
[1, 1, 1, 2, 2, 2, 2, 2, 1, 1]
[1, 1, 1, 2, 2, 3, 3, 3, 3, 3]
[1, 1, 1, 2, 2, 3, 4, 4, 4, 5]
[1, 1, 1, 2, 2, 3, 4, 5, 5, 6]
[1, 1, 1, 2, 2, 3, 4, 5, 6, 7]
[1, 1, 1, 2, 2, 3, 4, 5, 6, 8]

After the last iteration, we would have considered all the numbers and the number of ways to get the target would be the array element corresponding to the target value. In our case, Array[9] after the last iteration is 8.

Typedef function pointer?

  1. typedef is used to alias types; in this case you're aliasing FunctionFunc to void(*)().

  2. Indeed the syntax does look odd, have a look at this:

    typedef   void      (*FunctionFunc)  ( );
    //         ^                ^         ^
    //     return type      type name  arguments
    
  3. No, this simply tells the compiler that the FunctionFunc type will be a function pointer, it doesn't define one, like this:

    FunctionFunc x;
    void doSomething() { printf("Hello there\n"); }
    x = &doSomething;
    
    x(); //prints "Hello there"
    

Google Chrome Printing Page Breaks

It was working for me when I used padding like:

<div style="padding-top :200px;page-break-inside:avoid;">
   <div>My content</div>
</div>

SimpleDateFormat returns 24-hour date: how to get 12-hour date?

Referring to SimpleDataFormat JavaDoc:

Letter | Date or Time Component | Presentation | Examples
---------------------------------------------------------
   H   |  Hour in day (0-23)    |    Number    |    0
   h   |  Hour in am/pm (1-12)  |    Number    |    12

Merging two images in C#/.NET

basically i use this in one of our apps: we want to overlay a playicon over a frame of a video:

Image playbutton;
try
{
    playbutton = Image.FromFile(/*somekindofpath*/);
}
catch (Exception ex)
{
    return;
}

Image frame;
try
{
    frame = Image.FromFile(/*somekindofpath*/);
}
catch (Exception ex)
{
    return;
}

using (frame)
{
    using (var bitmap = new Bitmap(width, height))
    {
        using (var canvas = Graphics.FromImage(bitmap))
        {
            canvas.InterpolationMode = InterpolationMode.HighQualityBicubic;
            canvas.DrawImage(frame,
                             new Rectangle(0,
                                           0,
                                           width,
                                           height),
                             new Rectangle(0,
                                           0,
                                           frame.Width,
                                           frame.Height),
                             GraphicsUnit.Pixel);
            canvas.DrawImage(playbutton,
                             (bitmap.Width / 2) - (playbutton.Width / 2),
                             (bitmap.Height / 2) - (playbutton.Height / 2));
            canvas.Save();
        }
        try
        {
            bitmap.Save(/*somekindofpath*/,
                        System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        catch (Exception ex) { }
    }
}

jQuery.active function

For anyone trying to use jQuery.active with JSONP requests (like I was) you'll need enable it with this:

jQuery.ajaxPrefilter(function( options ) {
    options.global = true;
});

Keep in mind that you'll need a timeout on your JSONP request to catch failures.

Compare two files line by line and generate the difference in another file

If you need to solve this with coreutils the accepted answer is good:

comm -23 <(sort file1) <(sort file2) > file3

You can also use sd (stream diff), which doesn't require sorting nor process substitution and supports infinite streams, like so:

cat file1 | sd 'cat file2' > file3

Probably not that much of a benefit on this example, but still consider it; in some cases you won't be able to use comm nor grep -F nor diff.

Here's a blogpost I wrote about diffing streams on the terminal, which introduces sd.

php - insert a variable in an echo string

echo '<p class="paragraph'.$i.'"></p>';

Check if EditText is empty.

Try this out with using If ELSE If conditions. You can validate your editText fields easily.

 if(TextUtils.isEmpty(username)) {
                userNameView.setError("User Name Is Essential");
                return;
         } else  if(TextUtils.isEmpty(phone)) {
                phoneView.setError("Please Enter Your Phone Number");
                return;
            }

MVC 4 - how do I pass model data to a partial view?

Three ways to pass model data to partial view (there may be more)

This is view page

Method One Populate at view

@{    
    PartialViewTestSOl.Models.CountryModel ctry1 = new PartialViewTestSOl.Models.CountryModel();
    ctry1.CountryName="India";
    ctry1.ID=1;    

    PartialViewTestSOl.Models.CountryModel ctry2 = new PartialViewTestSOl.Models.CountryModel();
    ctry2.CountryName="Africa";
    ctry2.ID=2;

    List<PartialViewTestSOl.Models.CountryModel> CountryList = new List<PartialViewTestSOl.Models.CountryModel>();
    CountryList.Add(ctry1);
    CountryList.Add(ctry2);    

}

@{
    Html.RenderPartial("~/Views/PartialViewTest.cshtml",CountryList );
}

Method Two Pass Through ViewBag

@{
    var country = (List<PartialViewTestSOl.Models.CountryModel>)ViewBag.CountryList;
    Html.RenderPartial("~/Views/PartialViewTest.cshtml",country );
}

Method Three pass through model

@{
    Html.RenderPartial("~/Views/PartialViewTest.cshtml",Model.country );
}

enter image description here

How to set default Checked in checkbox ReactJS?

If the checkbox is created only with React.createElement then the property defaultChecked is used.

React.createElement('input',{type: 'checkbox', defaultChecked: false});

Credit to @nash_ag

How do you loop in a Windows batch file?

Type:

for /?

and you will get several pages of help text.

Socket send and receive byte array

There is a JDK socket tutorial here, which covers both the server and client end. That looks exactly like what you want.

(from that tutorial) This sets up to read from an echo server:

    echoSocket = new Socket("taranis", 7);
    out = new PrintWriter(echoSocket.getOutputStream(), true);
    in = new BufferedReader(new InputStreamReader(
                                echoSocket.getInputStream()));

taking a stream of bytes and converts to strings via the reader and using a default encoding (not advisable, normally).

Error handling and closing sockets/streams omitted from the above, but check the tutorial.

How to scroll to top of page with JavaScript/jQuery?

I remember seeing this posted somewhere else (I couldn't find where), but this works really well:

setTimeout(() => {
    window.scrollTo(0, 0);
}, 0);

It's weird, but the way it works is based off of the way JavaScript's stack queue works. The full explanation is found here in the Zero Delays section.

The basic idea is that the time for setTimeout doesn't actually specify the set amount of time it will wait, but the minimum amount of time it will wait. So when you tell it to wait 0ms, the browser runs all the other queued processes (like scrolling the window to where you were last) and then executes the callback.

Extract substring in Bash

A bash solution:

IFS="_" read -r x digs x <<<'someletters_12345_moreleters.ext'

This will clobber a variable called x. The var x could be changed to the var _.

input='someletters_12345_moreleters.ext'
IFS="_" read -r _ digs _ <<<"$input"

How do I escape only single quotes?

str_replace("'", "\'", $mystringWithSingleQuotes);

Node.js connect only works on localhost

To gain access for other users to your local machine, i usually use ngrok. Ngrok exposes your localhost to the web, and has an NPM wrapper that is simple to install and start:

$ npm install ngrok -g
$ ngrok http 3000

See this example usage:

enter image description here

In the above example, the locally running instance of sails at: localhost:3000 is now available on the Internet served at: http://69f8f0ee.ngrok.io or https://69f8f0ee.ngrok.io

MS-DOS Batch file pause with enter key

pause command is what you looking for. If you looking ONLY the case when enter is hit you can abuse the runas command:

runas /user:# "" >nul 2>&1

the screen will be frozen until enter is hit.What I like more than set/p= is that if you press other buttons than enter they will be not displayed.

sql like operator to get the numbers only

Try something like this - it works for the cases you have mentioned.

select * from tbl
where answer like '%[0-9]%'
and answer not like '%[:]%'
and answer not like '%[A-Z]%'

jQuery select change show/hide div event

Try:

if($("option[value='parcel']").is(":checked"))
   $('#row_dim').show();

Or even:

$(function() {
    $('#type').change(function(){
        $('#row_dim')[ ($("option[value='parcel']").is(":checked"))? "show" : "hide" ]();  
    });
});

JSFiddle: http://jsfiddle.net/3w5kD/

Make anchor link go some pixels above where it's linked to

If you use explicit anchor names such as,

<a name="sectionLink"></a>
<h1>Section<h1>

then in css you can simply set

A[name] {
    padding-top:100px;
}

This will work as long as your HREF anchor tags don't also specify a NAME attribute

Difference between @Mock and @InjectMocks

A "mocking framework", which Mockito is based on, is a framework that gives you the ability to create Mock objects ( in old terms these objects could be called shunts, as they work as shunts for dependend functionality ) In other words, a mock object is used to imitate the real object your code is dependend on, you create a proxy object with the mocking framework. By using mock objects in your tests you are essentially going from normal unit testing to integrational testing

Mockito is an open source testing framework for Java released under the MIT License, it is a "mocking framework", that lets you write beautiful tests with clean and simple API. There are many different mocking frameworks in the Java space, however there are essentially two main types of mock object frameworks, ones that are implemented via proxy and ones that are implemented via class remapping.

Dependency injection frameworks like Spring allow you to inject your proxy objects without modifying any code, the mock object expects a certain method to be called and it will return an expected result.

The @InjectMocks annotation tries to instantiate the testing object instance and injects fields annotated with @Mock or @Spy into private fields of the testing object.

MockitoAnnotations.initMocks(this) call, resets testing object and re-initializes mocks, so remember to have this at your @Before / @BeforeMethod annotation.

How to subtract X days from a date using Java calendar?

Someone recommended Joda Time so - I have been using this CalendarDate class http://calendardate.sourceforge.net

It's a somewhat competing project to Joda Time, but much more basic at only 2 classes. It's very handy and worked great for what I needed since I didn't want to use a package bigger than my project. Unlike the Java counterparts, its smallest unit is the day so it is really a date (not having it down to milliseconds or something). Once you create the date, all you do to subtract is something like myDay.addDays(-5) to go back 5 days. You can use it to find the day of the week and things like that. Another example:

CalendarDate someDay = new CalendarDate(2011, 10, 27);
CalendarDate someLaterDay = today.addDays(77);

And:

//print 4 previous days of the week and today
String dayLabel = "";
CalendarDate today = new CalendarDate(TimeZone.getDefault());
CalendarDateFormat cdf = new CalendarDateFormat("EEE");//day of the week like "Mon"
CalendarDate currDay = today.addDays(-4);
while(!currDay.isAfter(today)) {
    dayLabel = cdf.format(currDay);
    if (currDay.equals(today))
        dayLabel = "Today";//print "Today" instead of the weekday name
    System.out.println(dayLabel);
    currDay = currDay.addDays(1);//go to next day
}

Is there a way to get a <button> element to link to a location without wrapping it in an <a href ... tag?

Just do this

<button OnClick=" location.href='link.html' ">Visit Page Now</button>

Although, it's been a while since I've touched JavaScript - maybe location.href is outdated? Anyways, that's how I would do it.

Microsoft Excel mangles Diacritics in .csv files?

This is just of a question of character encodings. It looks like you're exporting your data as UTF-8: é in UTF-8 is the two-byte sequence 0xC3 0xA9, which when interpreted in Windows-1252 is é. When you import your data into Excel, make sure to tell it that the character encoding you're using is UTF-8.

LogisticRegression: Unknown label type: 'continuous' using sklearn in python

LogisticRegression is not for regression but classification !

The Y variable must be the classification class,

(for example 0 or 1)

And not a continuous variable,

that would be a regression problem.

android:drawableLeft margin and/or padding

android:drawablePadding is the easiest way to give padding to drawable icon but You can not give specific one side padding like paddingRight or paddingLeft of drawable icon.To achieve that you have to dig into it. And If you apply paddingLeft or paddingRight to EditText then it will place padding to entire EditText along with drawable icon.

<TextView android:layout_width="match_parent"
    android:padding="5dp"
    android:id="@+id/date"
    android:gravity="center|start"
    android:drawableEnd="@drawable/ic_calendar"
    android:background="@drawable/edit_background"
    android:hint="Not Selected"
    android:drawablePadding="10dp"
    android:paddingStart="10dp"
    android:paddingEnd="10dp"
    android:textColor="@color/black"
    android:layout_height="wrap_content"/>

How to wait for all threads to finish, using ExecutorService?

you should use executorService.shutdown() and executorService.awaitTermination method.

An example as follows :

public class ScheduledThreadPoolExample {

    public static void main(String[] args) throws InterruptedException {
        ScheduledExecutorService executorService = Executors.newScheduledThreadPool(5);
        executorService.scheduleAtFixedRate(() -> System.out.println("process task."),
                0, 1, TimeUnit.SECONDS);

        TimeUnit.SECONDS.sleep(10);
        executorService.shutdown();
        executorService.awaitTermination(1, TimeUnit.DAYS);
    }

}

How to list all the files in a commit?

Using standard git diff command (also good for scripting):

git diff --name-only <sha>^ <sha>

If you want also the status of the changed files:

git diff --name-status <sha>^ <sha>

This works well with merge commits.

Create Hyperlink in Slack

In addition to the ?ShiftU/CtrlShiftU solution, you can also add a link quickly by doing the following:

  1. Copy a URL to the clipboard
  2. Select the text in a slack message you are writing that you want to be a link
  3. Press ?V on Mac or CtrlV

I couldn't find it documented anywhere, but it works, and seems very handy.

How to Call a Function inside a Render in React/Jsx

To call the function you have to add ()

{this.renderIcon()}   

build-impl.xml:1031: The module has not been deployed

Start your IDE with administrative privilege( Windows: right click and run as admin), so that it has read write access to tomact folder for deployment. It worked for me.

Extracting hours from a DateTime (SQL Server 2005)

try this one too:

   DATEPART(HOUR,GETDATE()) 

How to generate an entity-relationship (ER) diagram using Oracle SQL Developer

I'm running SQL Developer 17.2.0.188 build 188.1159 which does indeed contain data modeling capability. I just created a relational model diagram via the menu: File->Data Modeler->Import->Data Dictionary....

I also have the stand-alone Data Modeler, which does the same thing.

As the Data Modeler tutorial states:

Figure 4: Relational model and diagram for HR

The diagram you’ve generated is not an ERD. Logical models are higher abstractions. An ERD represents entities and their attributes and relations, whereas a relational or physical model represents tables, columns, and foreign keys."

Xcode - iPhone - profile doesn't match any valid certificate-/private-key pair in the default keychain

I had a similar situation: multiple developers using the same private key, but I couldn't find mine anymore after upgrade to Lion. The very simple fix was to export the private key for the specific certificate (in my case the Development cert) from the other machine, move it to my computer and drag it into keychain access there. Xcode immediately picked it up and I was good to go.

Protect image download

As we know there is no proper method to avoid image theft. But we can reduce it for some extent. We can avoid those people who are not geek in computers to download the image as well as your code. Here are some JQuery tricks we should include in our site to reduce image theft

  • Disable right click
  • Disable Ctrl+ combination (ex Ctrl+s,Ctrl+u) [Better to disable Ctrl key ]

But user can also download the web page using developer tools in Firefox. We don't have solution for this because this will be on the client side and is provided by the user's browser.

You can find the code for all the above listed on stack overflow

How to convert index of a pandas dataframe into a column?

For MultiIndex you can extract its subindex using

df['si_name'] = R.index.get_level_values('si_name') 

where si_name is the name of the subindex.

Git Pull While Ignoring Local Changes?

I usually do:

git checkout .
git pull

In the project's root folder.

How to convert DATE to UNIX TIMESTAMP in shell script on MacOS

Alternatively you can install GNU date like so:

  1. install Homebrew: https://brew.sh/
  2. brew install coreutils
  3. add to your bash_profile: alias date="/usr/local/bin/gdate"
  4. date +%s 1547838127

Comments saying Mac has to be "different" simply reveal the commenter is ignorant of the history of UNIX. macOS is based on BSD UNIX, which is way older than Linux. Linux essentially was a copy of other UNIX systems, and Linux decided to be "different" by adopting GNU tools instead of BSD tools. GNU tools are more user friendly, but they're not usually found on any *BSD system (just the way it is).

Really, if you spend most of your time in Linux, but have a Mac desktop, you probably want to make the Mac work like Linux. There's no sense in trying to remember two different sets of options, or scripting for the mac's BSD version of Bash, unless you are writing a utility that you want to run on both BSD and GNU/Linux shells.

strange error in my Animation Drawable

Looks like whatever is in your Animation Drawable definition is too much memory to decode and sequence. The idea is that it loads up all the items and make them in an array and swaps them in and out of the scene according to the timing specified for each frame.

If this all can't fit into memory, it's probably better to either do this on your own with some sort of handler or better yet just encode a movie with the specified frames at the corresponding images and play the animation through a video codec.

Dynamically create and submit form

Yes, it is possible. One of the solutions is below (jsfiddle as a proof).

HTML:

<a id="fire" href="#" title="submit form">Submit form</a>

(see, above there is no form)

JavaScript:

jQuery('#fire').click(function(event){
    event.preventDefault();
    var newForm = jQuery('<form>', {
        'action': 'http://www.google.com/search',
        'target': '_top'
    }).append(jQuery('<input>', {
        'name': 'q',
        'value': 'stack overflow',
        'type': 'hidden'
    }));
    newForm.submit();
});

The above example shows you how to create form, how to add inputs and how to submit. Sometimes display of the result is forbidden by X-Frame-Options, so I have set target to _top, which replaces the main window's content. Alternatively if you set _blank, it can show within new window / tab.

How do I put the image on the right side of the text in a UIButton?

Do Yourself. Xcode10, swift4,

For programmatically UI design

enter image description here

 lazy var buttonFilter : ButtonRightImageLeftTitle = {
    var button = ButtonRightImageLeftTitle()
    button.setTitle("Playfir", for: UIControl.State.normal)
    button.setImage(UIImage(named: "filter"), for: UIControl.State.normal)
    button.backgroundColor = UIColor.red
    button.contentHorizontalAlignment = .left
    button.titleLabel?.font = UIFont.systemFont(ofSize: 16)
    return button
}()

Edge inset values are applied to a rectangle to shrink or expand the area represented by that rectangle. Typically, edge insets are used during view layout to modify the view’s frame. Positive values cause the frame to be inset (or shrunk) by the specified amount. Negative values cause the frame to be outset (or expanded) by the specified amount.

class ButtonRightImageLeftTitle: UIButton {

    override func layoutSubviews() {
        super.layoutSubviews()

        guard imageView != nil else { return }

        imageEdgeInsets = UIEdgeInsets(top: 5, left: (bounds.width - 35), bottom: 5, right: 5)
        titleEdgeInsets = UIEdgeInsets(top: 0, left: -((imageView?.bounds.width)! + 10), bottom: 0, right: 0 )

    }
}

for StoryBoard UI design

enter image description here enter image description here

What exactly should be set in PYTHONPATH?

Here is what I learned: PYTHONPATH is a directory to add to the Python import search path "sys.path", which is made up of current dir. CWD, PYTHONPATH, standard and shared library, and customer library. For example:

% python3 -c "import sys;print(sys.path)"
['', 
'/home/username/Documents/DjangoTutorial/mySite', 
'/usr/lib/python3.6', '/usr/lib/python3.6/lib-dynload', 
'/usr/local/lib/python3.6/dist-packages', '/usr/lib/python3/dist-packages']

where the first path '' denotes the current dir., the 2nd path is via

%export PYTHONPATH=/home/username/Documents/DjangoTutorial/mySite 

which can be added to ~/.bashrc to make it permanent, and the rest are Python standard and dynamic shared library plus third-party library such as django.

As said not to mess with PYTHONHOME, even setting it to '' or 'None' will cause python3 shell to stop working:

% export PYTHONHOME=''
% python3
Fatal Python error: Py_Initialize: Unable to get the locale encoding
ModuleNotFoundError: No module named 'encodings'

Current thread 0x00007f18a44ff740 (most recent call first):
Aborted (core dumped)

Note that if you start a Python script, the CWD will be the script's directory. For example:

username@bud:~/Documents/DjangoTutorial% python3 mySite/manage.py runserver
==== Printing sys.path ====
/home/username/Documents/DjangoTutorial/mySite # CWD is where manage.py resides
/usr/lib/python3.6
/usr/lib/python3.6/lib-dynload
/usr/local/lib/python3.6/dist-packages
/usr/lib/python3/dist-packages

You can also append a path to sys.path at run-time: Suppose you have a file Fibonacci.py in ~/Documents/Python directory:

username@bud:~/Documents/DjangoTutorial% python3 
>>> sys.path.append("/home/username/Documents")
>>> print(sys.path)
['', '/usr/lib/python3.6', '/usr/lib/python3.6/lib-dynload', 
'/usr/local/lib/python3.6/dist-packages', '/usr/lib/python3/dist-packages', 
'/home/username/Documents']
>>> from Python import Fibonacci as fibo

or via

% PYTHONPATH=/home/username/Documents:$PYTHONPATH
% python3
>>> print(sys.path)
['', 
'/home/username/Documents', '/home/username/Documents/DjangoTutorial/mySite', 
'/usr/lib/python3.6', '/usr/lib/python3.6/lib-dynload', 
'/usr/local/lib/python3.6/dist-packages', '/usr/lib/python3/dist-packages']
>>> from Python import Fibonacci as fibo

Find out if string ends with another string in C++

another option is to use regex. The following code makes the search insensitive to upper/lower case:

bool endsWithIgnoreCase(const std::string& str, const std::string& suffix) {
  return std::regex_search(str,
     std::regex(std::string(suffix) + "$", std::regex_constants::icase));
}

probably not so efficient, but easy to implement.

Get the Application Context In Fragment In Android?

You can get the context using getActivity().getApplicationContext();

How do I grab an INI value within a shell script?

The answer of "Karen Gabrielyan" among another answers was the best but in some environments we dont have awk, like typical busybox, i changed the answer by below code.

trim()
{
    local trimmed="$1"

    # Strip leading space.
    trimmed="${trimmed## }"
    # Strip trailing space.
    trimmed="${trimmed%% }"

    echo "$trimmed"
}


  function parseIniFile() { #accepts the name of the file to parse as argument ($1)
        #declare syntax below (-gA) only works with bash 4.2 and higher
        unset g_iniProperties
        declare -gA g_iniProperties
        currentSection=""
        while read -r line
        do
            if [[ $line = [*  ]] ; then
                if [[ $line = [* ]] ; then 
                    currentSection=$(echo $line | sed -e 's/\r//g' | tr -d "[]")  
                fi
            else
                if [[ $line = *=*  ]] ; then
                    cleanLine=$(echo $line | sed -e 's/\r//g')
                    key=$(trim $currentSection.$(echo $cleanLine | cut -d'=' -f1'))
                    value=$(trim $(echo $cleanLine | cut -d'=' -f2))
                    g_iniProperties[$key]=$value
                fi
            fi;
        done < $1
    }

Best data type for storing currency values in a MySQL database

Something like Decimal(19,4) usually works pretty well in most cases. You can adjust the scale and precision to fit the needs of the numbers you need to store. Even in SQL Server, I tend not to use "money" as it's non-standard.

How do I prevent a Gateway Timeout with FastCGI on Nginx

If you use unicorn.

Look at top on your server. Unicorn likely is using 100% of CPU right now. There are several reasons of this problem.

  • You should check your HTTP requests, some of their can be very hard.

  • Check unicorn's version. May be you've updated it recently, and something was broken.

Get last 5 characters in a string

Old thread, but just only to say: to use the classic Left(), Right(), Mid() right now you don't need to write the full path (Microsoft.VisualBasic.Strings). You can use fast and easily like this:

Strings.Right(yourString, 5)

PHP display current server path

You can also use the following alternative realpath.

Create a file called path.php

Put the following code inside by specifying the name of the created file.

<?php 
    echo realpath('path.php'); 
?>

A php file that you can move to all your folders to always have the absolute path from where the executed file is located.

;-)

How to import large sql file in phpmyadmin

One solution is to use the command line;

mysql -h yourhostname -u username -p databasename < yoursqlfile.sql

Just ensure the path to the SQL file to import is stated explicitly.

In my case, I used this;

mysql -h localhost -u root -p databasename < /home/ejalee/dumps/mysqlfile.sql

Voila! you are good to go.

highlight the navigation menu for the current page

<script id="add-active-to-current-page-nav-link" type="text/javascript">
    function setSelectedPageNav() {
        var pathName = document.location.pathname;
        if ($("nav ul li a") != null) {
            var currentLink = $("nav ul li a[href='" + pathName + "']");
            currentLink.addClass("active");
        }
    }
    setSelectedPageNav();
</script>

How to clear PermGen space Error in tomcat

If tomcat is running as Windows Service neither CATALINA_OPTS nor JAVA_OPTS seems to have any effect.

You need to set it in Java options in GUI.

The below link explains it well

http://www.12robots.com/index.cfm/2010/10/8/Giving-more-memory-to-the-Tomcat-Service-in-Windows

Cannot install packages using node package manager in Ubuntu

Your System is not able to detect the path node js binary.

1.which node

2.Then soft link node to nodejs

ln -s [the path of nodejs] /usr/bin/node 

I am assuming /usr/bin is in your execution path. Then you can test by typing node or npm into your command line, and everything should work now.

How to debug an apache virtual host configuration?

If you are trying to debug your virtual host configuration, you may find the Apache -S command line switch useful. That is, type the following command:

httpd -S

This command will dump out a description of how Apache parsed the configuration file. Careful examination of the IP addresses and server names may help uncover configuration mistakes. (See the docs for the httpd program for other command line options).

How do I change the select box arrow

Working with just one selector:

select {
    width: 268px;
    padding: 5px;
    font-size: 16px;
    line-height: 1;
    border: 0;
    border-radius: 5px;
    height: 34px;
    background: url(http://cdn1.iconfinder.com/data/icons/cc_mono_icon_set/blacks/16x16/br_down.png) no-repeat right #ddd;
    -webkit-appearance: none;
    background-position-x: 244px;
}

fiddler

Convert dictionary values into array

These days, once you have LINQ available, you can convert the dictionary keys and their values to a single string.

You can use the following code:

// convert the dictionary to an array of strings
string[] strArray = dict.Select(x => ("Key: " + x.Key + ", Value: " + x.Value)).ToArray();

// convert a string array to a single string
string result = String.Join(", ", strArray);

How to make an Asynchronous Method return a value?

Use a BackgroundWorker. It will allow you to get callbacks on completion and allow you to track progress. You can set the Result value on the event arguments to the resulting value.

    public void UseBackgroundWorker()
    {
        var worker = new BackgroundWorker();
        worker.DoWork += DoWork;
        worker.RunWorkerCompleted += WorkDone;
        worker.RunWorkerAsync("input");
    }

    public void DoWork(object sender, DoWorkEventArgs e)
    {
        e.Result = e.Argument.Equals("input");
        Thread.Sleep(1000);
    }

    public void WorkDone(object sender, RunWorkerCompletedEventArgs e)
    {
        var result = (bool) e.Result;
    }

Adding elements to a C# array

Don't use an array - use a generic List<T> which allows you to add items dynamically.

If this is not an option, you can use Array.Copy or Array.CopyTo to copy the array into a larger array.

Oracle insert if not exists statement

MERGE INTO OPT
USING
    (SELECT 1 "one" FROM dual) 
ON
    (OPT.email= '[email protected]' and OPT.campaign_id= 100) 
WHEN NOT matched THEN
INSERT (email, campaign_id)
VALUES ('[email protected]',100) 
;

How to make parent wait for all child processes to finish?

POSIX defines a function: wait(NULL);. It's the shorthand for waitpid(-1, NULL, 0);, which will suspends the execution of the calling process until any one child process exits. Here, 1st argument of waitpid indicates wait for any child process to end.

In your case, have the parent call it from within your else branch.

Catching KeyboardInterrupt in Python during program shutdown

You could ignore SIGINTs after shutdown starts by calling signal.signal(signal.SIGINT, signal.SIG_IGN) before you start your cleanup code.

How to set full calendar to a specific start date when it's initialized for the 1st time?

For v5 please use initialDate instead of defaultDate. Simply renamed option

eg

var calendarEl = document.getElementById('calendar');
var calendar = new FullCalendar.Calendar(calendarEl, {
     ...
     initialDate: '2020-09-02',
     ...
});

Oracle: is there a tool to trace queries, like Profiler for sql server?

Try PL/SQL Developer it has a nice user friendly GUI interface to the profiler. It's pretty nice give the trial a try. I swear by this tool when working on Oracle databases.

http://www.allroundautomations.com/plsqldev.html?gclid=CM6pz8e04p0CFQjyDAodNXqPDw

Easiest way to activate PHP and MySQL on Mac OS 10.6 (Snow Leopard), 10.7 (Lion), 10.8 (Mountain Lion)?

It's an invisible folder. Just hit Command + Shift + G (takes you to the Go to Folder menu item) and type /etc/.

Then it will take you to inside that folder.

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

In python 3, if you're using unittest.TestCase:

  • You must have an empty (or otherwise) __init__.py file in your test directory (must be named test/)
  • Your test files inside test/ match the pattern test_*.py. They can be inside a subdirectory under test/, and those subdirs can be named as anything.

Then, you can run all the tests with:

python -m unittest

Done! A solution less than 100 lines. Hopefully another python beginner saves time by finding this.

How do I POST an array of objects with $.ajax (jQuery or Zepto)

Be sure to stringify before sending. I leaned on the libraries too much and thought they would encode properly based on the contentType I was posting, but they do not seem to.

Works:

$.ajax({
    url: _saveAllDevicesUrl
,   type: 'POST'
,   contentType: 'application/json'
,   data: JSON.stringify(postData) //stringify is important
,   success: _madeSave.bind(this)
});

I prefer this method to using a plugin like $.toJSON, although that does accomplish the same thing.

SQL Server 2012 can't start because of a login failure

I don't know how good of a solution this is it, but after following some of the other answer to this question without success, i resolved setting the connection user of the service MSSQLSERVER to "Local Service".

N.B: i'm using SQL Server 2017.

Center the nav in Twitter Bootstrap

.navbar-right { 
    margin-left:auto;
    margin-right:auto; 
    max-width :40%;   
    float:none !important;
}

just copy this code and change max-width as you like

Convert dateTime to ISO format yyyy-mm-dd hh:mm:ss in C#

For those who are using this format all the timme like me I did an extension method. I just wanted to share because I think it can be usefull to you.

     /// <summary>
    /// Convert a date to a human readable ISO datetime format. ie. 2012-12-12 23:01:12
    /// this method must be put in a static class. This will appear as an available function
    /// on every datetime objects if your static class namespace is declared.
    /// </summary>
    public static string ToIsoReadable(this DateTime dateTime)
    {
        return dateTime.ToString("yyyy-MM-dd HH':'mm':'ss");
    }

Jquery checking success of ajax post

This style is also possible:

$.get("mypage.html")
    .done(function(result){
        alert("done. read "+result.length+" characters.");
    })
    .fail(function(jqXHR, textStatus, errorThrown){
        alert("fail. status: "+textStatus);
    })

Is it possible to get element from HashMap by its position?

Another working approach is transforming map values into an array and then retrieve element at index. Test run of 100 000 element by index searches in LinkedHashMap of 100 000 objects using following approaches led to following results:

//My answer:
public Particle getElementByIndex(LinkedHashMap<Point, Particle> map,int index){
    return map.values().toArray(new Particle[map.values().size()])[index];
} //68 965 ms

//Syd Lambert's answer:
public Particle getElementByIndex(LinkedHashMap<Point, Particle> map,int index){
    return map.get( (map.keySet().toArray())[ index ] );
} //80 700 ms

All in all retrieving element by index from LinkedHashMap seems to be pretty heavy operation.

Why is width: 100% not working on div {display: table-cell}?

I figured this one out. I know this will help someone someday.

How to Vertically & Horizontally Center a Div Over a Relatively Positioned Image

The key was a 3rd wrapper. I would vote up any answer that uses less wrappers.

HTML

<div class="wrapper">
    <img src="my-slide.jpg">
    <div class="outer-wrapper">
        <div class="table-wrapper">
            <div class="table-cell-wrapper">
                <h1>My Title</h1>
                <p>Subtitle</p>
            </div>
        </div>
    </div>
</div>

CSS

html, body {
margin: 0; padding: 0;
width: 100%; height: 100%;
}

ul {
    width: 100%;
    height: 100%;
    list-style-position: outside;
    margin: 0; padding: 0;
}

li {
    width: 100%;
    display: table;
}

img {
    width: 100%;
    height: 100%;
}

.outer-wrapper {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  margin: 0; padding: 0;
}

.table-wrapper {
  width: 100%;
  height: 100%;
  display: table;
  vertical-align: middle;
  text-align: center;
}

.table-cell-wrapper {
  width: 100%;
  height: 100%;  
  display: table-cell;
  vertical-align: middle;
  text-align: center;
}

You can see the working jsFiddle here.

Connection reset by peer: mod_fcgid: error reading data from FastCGI server

In CentOS releases suexec is compiled to run only in /var/www. If you try to set a DocumentRoot somewhere else you have to recompile it - the error in apache log are: (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server Premature end of script headers: php5.fcgi

Function to calculate distance between two coordinates

I have written the function to find distance between two coordinates. It will return distance in meter.

 function findDistance() {
   var R = 6371e3; // R is earth’s radius
   var lat1 = 23.18489670753479; // starting point lat
   var lat2 = 32.726601;         // ending point lat
   var lon1 = 72.62524545192719; // starting point lon
   var lon2 = 74.857025;         // ending point lon
   var lat1radians = toRadians(lat1);
   var lat2radians = toRadians(lat2);

   var latRadians = toRadians(lat2-lat1);
   var lonRadians = toRadians(lon2-lon1);

   var a = Math.sin(latRadians/2) * Math.sin(latRadians/2) +
        Math.cos(lat1radians) * Math.cos(lat2radians) *
        Math.sin(lonRadians/2) * Math.sin(lonRadians/2);
   var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

   var d = R * c;

   console.log(d)
}

function toRadians(val){
    var PI = 3.1415926535;
    return val / 180.0 * PI;
}

Plot mean and standard deviation

You may find an answer with this example : errorbar_demo_features.py

"""
Demo of errorbar function with different ways of specifying error bars.

Errors can be specified as a constant value (as shown in `errorbar_demo.py`),
or as demonstrated in this example, they can be specified by an N x 1 or 2 x N,
where N is the number of data points.

N x 1:
    Error varies for each point, but the error values are symmetric (i.e. the
    lower and upper values are equal).

2 x N:
    Error varies for each point, and the lower and upper limits (in that order)
    are different (asymmetric case)

In addition, this example demonstrates how to use log scale with errorbar.
"""
import numpy as np
import matplotlib.pyplot as plt

# example data
x = np.arange(0.1, 4, 0.5)
y = np.exp(-x)
# example error bar values that vary with x-position
error = 0.1 + 0.2 * x
# error bar values w/ different -/+ errors
lower_error = 0.4 * error
upper_error = error
asymmetric_error = [lower_error, upper_error]

fig, (ax0, ax1) = plt.subplots(nrows=2, sharex=True)
ax0.errorbar(x, y, yerr=error, fmt='-o')
ax0.set_title('variable, symmetric error')

ax1.errorbar(x, y, xerr=asymmetric_error, fmt='o')
ax1.set_title('variable, asymmetric error')
ax1.set_yscale('log')
plt.show()

Which plots this:

enter image description here

default web page width - 1024px or 980px?

980 is not the "defacto standard", you'll generally see most people targeting a size a little bit less than 1024px wide to account for browser chrome such as scrollbars, etc.

Usually people target between 960 and 990px wide. Often people use a grid system (like 960.gs) which is opinionated about what the default width should be.

Also note, just recently the most common screen size now averages quite a bit bigger than 1024px wide, ranking in at 1366px wide. See http://techcrunch.com/2012/04/11/move-over-1024x768-the-most-popular-screen-resolution-on-the-web-is-now-1366x768/

ObservableCollection not noticing when Item in it changes (even with INotifyPropertyChanged)

ObservableCollection will not propagate individual item changes as CollectionChanged events. You will either need to subscribe to each event and forward it manually, or you can check out the BindingList[T] class, which will do this for you.

Visual C++: How to disable specific linker warnings?

The PDB file is typically used to store debug information. This warning is caused probably because the file vc80.pdb is not found when linking the target object file. Read the MSDN entry on LNK4099 here.

Alternatively, you can turn off debug information generation from the Project Properties > Linker > Debugging > Generate Debug Info field.

How do you determine what technology a website is built on?

There is also W3Techs, which shows you much of that information.

How to make Bitmap compress without change the bitmap size?

I have done this way:

Get Compressed Bitmap from Singleton class:

ImageView imageView = (ImageView)findViewById(R.id.imageView);
Bitmap bitmap = ImageUtils.getInstant().getCompressedBitmap("Your_Image_Path_Here");
imageView.setImageBitmap(bitmap);

ImageUtils.java:

public class ImageUtils {

    public static ImageUtils mInstant;

    public static ImageUtils getInstant(){
        if(mInstant==null){
            mInstant = new ImageUtils();
        }
        return mInstant;
    }

    public  Bitmap getCompressedBitmap(String imagePath) {
        float maxHeight = 1920.0f;
        float maxWidth = 1080.0f;
        Bitmap scaledBitmap = null;
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        Bitmap bmp = BitmapFactory.decodeFile(imagePath, options);

        int actualHeight = options.outHeight;
        int actualWidth = options.outWidth;
        float imgRatio = (float) actualWidth / (float) actualHeight;
        float maxRatio = maxWidth / maxHeight;

        if (actualHeight > maxHeight || actualWidth > maxWidth) {
            if (imgRatio < maxRatio) {
                imgRatio = maxHeight / actualHeight;
                actualWidth = (int) (imgRatio * actualWidth);
                actualHeight = (int) maxHeight;
            } else if (imgRatio > maxRatio) {
                imgRatio = maxWidth / actualWidth;
                actualHeight = (int) (imgRatio * actualHeight);
                actualWidth = (int) maxWidth;
            } else {
                actualHeight = (int) maxHeight;
                actualWidth = (int) maxWidth;

            }
        }

        options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);
        options.inJustDecodeBounds = false;
        options.inDither = false;
        options.inPurgeable = true;
        options.inInputShareable = true;
        options.inTempStorage = new byte[16 * 1024];

        try {
            bmp = BitmapFactory.decodeFile(imagePath, options);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();

        }
        try {
            scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight, Bitmap.Config.ARGB_8888);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();
        }

        float ratioX = actualWidth / (float) options.outWidth;
        float ratioY = actualHeight / (float) options.outHeight;
        float middleX = actualWidth / 2.0f;
        float middleY = actualHeight / 2.0f;

        Matrix scaleMatrix = new Matrix();
        scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);

        Canvas canvas = new Canvas(scaledBitmap);
        canvas.setMatrix(scaleMatrix);
        canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2, middleY - bmp.getHeight() / 2, new Paint(Paint.FILTER_BITMAP_FLAG));

        ExifInterface exif = null;
        try {
            exif = new ExifInterface(imagePath);
            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 0);
            Matrix matrix = new Matrix();
            if (orientation == 6) {
                matrix.postRotate(90);
            } else if (orientation == 3) {
                matrix.postRotate(180);
            } else if (orientation == 8) {
                matrix.postRotate(270);
            }
            scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix, true);
        } catch (IOException e) {
            e.printStackTrace();
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 85, out);

        byte[] byteArray = out.toByteArray();

        Bitmap updatedBitmap = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length);

        return updatedBitmap;
    }

    private int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        final float totalPixels = width * height;
        final float totalReqPixelsCap = reqWidth * reqHeight * 2;

        while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
            inSampleSize++;
        }
        return inSampleSize;
    }
}

Dimensions are same after compressing Bitmap.

How did I checked ?

Bitmap beforeBitmap = BitmapFactory.decodeFile("Your_Image_Path_Here");
Log.i("Before Compress Dimension", beforeBitmap.getWidth()+"-"+beforeBitmap.getHeight());

Bitmap afterBitmap = ImageUtils.getInstant().getCompressedBitmap("Your_Image_Path_Here");
Log.i("After Compress Dimension", afterBitmap.getWidth() + "-" + afterBitmap.getHeight());

Output:

Before Compress : Dimension: 1080-1452
After Compress : Dimension: 1080-1452

Hope this will help you.

Uploading Images to Server android

Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, 1);

ABOVE CODE TO SELECT IMAGE FROM GALLERY

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 1)
        if (resultCode == Activity.RESULT_OK) {
            Uri selectedImage = data.getData();

            String filePath = getPath(selectedImage);
            String file_extn = filePath.substring(filePath.lastIndexOf(".") + 1);
            image_name_tv.setText(filePath);

            try {
                if (file_extn.equals("img") || file_extn.equals("jpg") || file_extn.equals("jpeg") || file_extn.equals("gif") || file_extn.equals("png")) {
                    //FINE
                } else {
                    //NOT IN REQUIRED FORMAT
                }
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
}

public String getPath(Uri uri) {
    String[] projection = {MediaColumns.DATA};
    Cursor cursor = managedQuery(uri, projection, null, null, null);
    column_index = cursor
            .getColumnIndexOrThrow(MediaColumns.DATA);
    cursor.moveToFirst();
    imagePath = cursor.getString(column_index);

    return cursor.getString(column_index);
}

NOW POST THE DATA USING MULTIPART FORM DATA

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("LINK TO SERVER");

Multipart FORM DATA

MultipartEntity mpEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
if (filePath != null) {
    File file = new File(filePath);
    Log.d("EDIT USER PROFILE", "UPLOAD: file length = " + file.length());
    Log.d("EDIT USER PROFILE", "UPLOAD: file exist = " + file.exists());
    mpEntity.addPart("avatar", new FileBody(file, "application/octet"));
}

FINALLY POST DATA TO SERVER

httppost.setEntity(mpEntity);
HttpResponse response = httpclient.execute(httppost);

Regular expression to get a string between two strings in Javascript

If the data is on multiple lines then you may have to use the following,

/My cow ([\s\S]*)milk/gm

My cow always gives 
milk

Regex 101 example

How does a Linux/Unix Bash script know its own PID?

use $BASHPID or $$

See the [manual][1] for more information, including differences between the two.

TL;DRTFM

  • $$ Expands to the process ID of the shell.
    • In a () subshell, it expands to the process ID of the invoking shell, not the subshell.
  • $BASHPID Expands to the process ID of the current Bash process (new to bash 4).

NullInjectorError: No provider for AngularFirestore

I solved this problem by just removing firestore from:

import { AngularFirestore } from '@angular/fire/firestore/firestore';

in my component.ts file. as use only:

import { AngularFirestore } from '@angular/fire/firestore';

this can be also your problem.

What is the difference between i++ and ++i?

Oddly it looks like the other two answers don't spell it out, and it's definitely worth saying:


i++ means 'tell me the value of i, then increment'

++i means 'increment i, then tell me the value'


They are Pre-increment, post-increment operators. In both cases the variable is incremented, but if you were to take the value of both expressions in exactly the same cases, the result will differ.

How can I insert new line/carriage returns into an element.textContent?

Change the h1.textContent to h1.innerHTML and use <br> to go to the new line.

When to use IList and when to use List

AList object allows you to create a list, add things to it, remove it, update it, index into it and etc. List is used whenever you just want a generic List where you specify object type in it and that's it.

IList on the other hand is an Interface. Basically, if you want to create your own type of List, say a list class called BookList, then you can use the Interface to give you basic methods and structure to your new class. IList is for when you want to create your own, special sub-class that implements List.

Another difference is: IList is an Interface and cannot be instantiated. List is a class and can be instantiated. It means:

IList<string> MyList = new IList<string>();

List<string> MyList = new List<string>

Cast from VARCHAR to INT - MySQL

For casting varchar fields/values to number format can be little hack used:

SELECT (`PROD_CODE` * 1) AS `PROD_CODE` FROM PRODUCT`

import module from string variable

spent some time trying to import modules from a list, and this is the thread that got me most of the way there - but I didnt grasp the use of ___import____ -

so here's how to import a module from a string, and get the same behavior as just import. And try/except the error case, too. :)

  pipmodules = ['pycurl', 'ansible', 'bad_module_no_beer']
  for module in pipmodules:
      try:
          # because we want to import using a variable, do it this way
          module_obj = __import__(module)
          # create a global object containging our module
          globals()[module] = module_obj
      except ImportError:
          sys.stderr.write("ERROR: missing python module: " + module + "\n")
          sys.exit(1)

and yes, for python 2.7> you have other options - but for 2.6<, this works.

VBScript How can I Format Date?

Although answer is provided I found simpler solution:

Date:

01/20/2017

By doing replace

CurrentDate = replace(date, "/", "-")

It will output:

01-20-2017

Is it possible to use 'else' in a list comprehension?

Also, would I be right in concluding that a list comprehension is the most efficient way to do this?

Maybe. List comprehensions are not inherently computationally efficient. It is still running in linear time.

From my personal experience: I have significantly reduced computation time when dealing with large data sets by replacing list comprehensions (specifically nested ones) with for-loop/list-appending type structures you have above. In this application I doubt you will notice a difference.

How do I add a Font Awesome icon to input field?

For those, who are wondering how to get FontAwesome icons to drupal input, you have to decode_entities first like so:

$form['submit'] = array(
'#type' => 'submit',
'#value' => decode_entities('&#xf014;'), // code for FontAwesome trash icon
// etc.
);

How do I extract text that lies between parentheses (round brackets)?

Use a Regular Expression:

string test = "(test)"; 
string word = Regex.Match(test, @"\((\w+)\)").Groups[1].Value;
Console.WriteLine(word);

Downloading jQuery UI CSS from Google's CDN

The Google AJAX Libraries API, which includes jQuery UI (currently v1.10.3), also includes popular themes as per the jQuery UI blog:

Google Ajax Libraries API (CDN)

Filtering lists using LINQ

I couldn't figure out how to do this in pure MS LINQ, so I wrote my own extension method to do it:

public static bool In<T>(this T objToCheck, params T[] values)
{
    if (values == null || values.Length == 0) 
    {
        return false; //early out
    }
    else
    {
        foreach (T t in values)
        {
            if (t.Equals(objToCheck))
                return true;   //RETURN found!
        }

        return false; //nothing found
    }
}

$ is not a function - jQuery error

In Wordpress jQuery.noConflict() is called on the jQuery file it includes (scroll to the bottom of the file it's including for jQuery to see this), which means $ doesn't work, but jQuery does, so your code should look like this:

<script type="text/javascript">
  jQuery(function($) {
    for(var i=0; i <= 20; i++) 
      $("ol li:nth-child(" + i + ")").addClass('olli' + i);
  });
</script>

Postgresql GROUP_CONCAT equivalent?

SELECT array_to_string(array(SELECT a FROM b),', ');

Will do as well.

Get DataKey values in GridView RowCommand

foreach (GridViewRow gvr in gvMyGridView.Rows)
{
    string PrimaryKey = gvMyGridView.DataKeys[gvr.RowIndex].Values[0].ToString();
}

You can use this code while doing an iteration with foreach or for any GridView event like OnRowDataBound.

Here you can input multiple values for DataKeyNames by separating with comma ,. For example, DataKeyNames="ProductID,ItemID,OrderID".

You can now access each of DataKeys by providing its index like below:

string ProductID = gvMyGridView.DataKeys[gvr.RowIndex].Values[0].ToString();
string ItemID = gvMyGridView.DataKeys[gvr.RowIndex].Values[1].ToString();
string OrderID = gvMyGridView.DataKeys[gvr.RowIndex].Values[2].ToString();

You can also use Key Name instead of its index to get the values from DataKeyNames collection like below:

string ProductID = gvMyGridView.DataKeys[gvr.RowIndex].Values["ProductID"].ToString();
string ItemID = gvMyGridView.DataKeys[gvr.RowIndex].Values["ItemID"].ToString();
string OrderID = gvMyGridView.DataKeys[gvr.RowIndex].Values["OrderID"].ToString();

Generate an integer sequence in MySQL

There is a way to get a range of values in a single query, but its a bit slow. It can be sped up by using cache tables.

assume you want a select with a range of all BOOLEAN values:

SELECT 0 as b UNION SELECT 1 as b;

we can make a view

CREATE VIEW ViewBoolean AS SELECT 0 as b UNION SELECT 1 as b;

then you can do a Byte by

CREATE VIEW ViewByteValues AS
SELECT b0.b + b1.b*2 + b2.b*4 + b3.b*8 + b4.b*16 + b5.b*32 + b6.b*64 + b7.b*128 as v FROM
ViewBoolean b0,ViewBoolean b1,ViewBoolean b2,ViewBoolean b3,ViewBoolean b4,ViewBoolean b5,ViewBoolean b6,ViewBoolean b7;

then you can do a

CREATE VIEW ViewInt16 AS
SELECT b0.v + b1.v*256 as v FROM
ViewByteValues b0,ViewByteValues b1;

then you can do a

SELECT v+MIN as x FROM ViewInt16 WHERE v<MAX-MIN;

To speed this up I skipped the auto-calculation of byte values and made myself a

CREATE VIEW ViewByteValues AS
SELECT 0 as v UNION SELECT 1 as v UNION SELECT ...
...
...254 as v UNION SELECT 255 as v;

If you need a range of dates you can do.

SELECT DATE_ADD('start_date',v) as day FROM ViewInt16 WHERE v<NumDays;

or

SELECT DATE_ADD('start_date',v) as day FROM ViewInt16 WHERE day<'end_date';

you might be able to speed this up with the slightly faster MAKEDATE function

SELECT MAKEDATE(start_year,1+v) as day FRON ViewInt16 WHERE day>'start_date' AND day<'end_date';

Please note that this tricks are VERY SLOW and only allow the creation of FINITE sequences in a pre-defined domain (for example int16 = 0...65536 )

I am sure you can modify the queries a bit to speed things up by hinting to MySQL where to stop calculating ;) (using ON clauses instead of WHERE clauses and stuff like that)

For example:

SELECT MIN + (b0.v + b1.v*256 + b2.v*65536 + b3.v*16777216) FROM
ViewByteValues b0,
ViewByteValues b1,
ViewByteValues b2,
ViewByteValues b3
WHERE (b0.v + b1.v*256 + b2.v*65536 + b3.v*16777216) < MAX-MIN;

will keep your SQL server busy for a few hours

However

SELECT MIN + (b0.v + b1.v*256 + b2.v*65536 + b3.v*16777216) FROM
ViewByteValues b0
INNER JOIN ViewByteValues b1 ON (b1.v*256<(MAX-MIN))
INNER JOIN ViewByteValues b2 ON (b2.v*65536<(MAX-MIN))
INNER JOIN ViewByteValues b3 ON (b3.v*16777216<(MAX-MIN)
WHERE (b0.v + b1.v*256 + b2.v*65536 + b3.v*16777216) < (MAX-MIN);

will run reasonably fast - even if MAX-MIN is huge as long as you limit the result with LIMIT 1,30 or something. a COUNT(*) however will take ages and if you make the mistake of adding ORDER BY when MAX-MIN is bigger than say 100k it will again take several seconds to calculate...

Using OpenSSL what does "unable to write 'random state'" mean?

One other issue on the Windows platform, make sure you are running your command prompt as an Administrative User!

I don't know how many times this has bitten me...

Is there a performance difference between CTE , Sub-Query, Temporary Table or Table Variable?

There is no rule. I find CTEs more readable, and use them unless they exhibit some performance problem, in which case I investigate the actual problem rather than guess that the CTE is the problem and try to re-write it using a different approach. There is usually more to the issue than the way I chose to declaratively state my intentions with the query.

There are certainly cases when you can unravel CTEs or remove subqueries and replace them with a #temp table and reduce duration. This can be due to various things, such as stale stats, the inability to even get accurate stats (e.g. joining to a table-valued function), parallelism, or even the inability to generate an optimal plan because of the complexity of the query (in which case breaking it up may give the optimizer a fighting chance). But there are also cases where the I/O involved with creating a #temp table can outweigh the other performance aspects that may make a particular plan shape using a CTE less attractive.

Quite honestly, there are way too many variables to provide a "correct" answer to your question. There is no predictable way to know when a query may tip in favor of one approach or another - just know that, in theory, the same semantics for a CTE or a single subquery should execute the exact same. I think your question would be more valuable if you present some cases where this is not true - it may be that you have discovered a limitation in the optimizer (or discovered a known one), or it may be that your queries are not semantically equivalent or that one contains an element that thwarts optimization.

So I would suggest writing the query in a way that seems most natural to you, and only deviate when you discover an actual performance problem the optimizer is having. Personally I rank them CTE, then subquery, with #temp table being a last resort.

Splitting String with delimiter

Try:

def (value1, value2) = '1128-2'.tokenize( '-' )

docker : invalid reference format

This also happens when you use development docker compose like the below, in production. You don't want to be building images in production as that breaks the ideology of containers. We should be deploying images:

  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000"

Change that to use the built image:

  web:
    command: /bin/bash run.sh
    image: registry.voxcloud.co.za:9000/dyndns_api_web:0.1
    ports:
      - "8000:8000"

react router v^4.0.0 Uncaught TypeError: Cannot read property 'location' of undefined

Replace

import { Router, Route, Link, browserHistory } from 'react-router';

With

import { BrowserRouter as Router, Route } from 'react-router-dom';

It will start working. It is because react-router-dom exports BrowserRouter

Java Read Large Text File With 70million line of text

I tried the following three methods, my file size is 1M, and I got results:

enter image description here

I run the program several times it looks that BufferedReader is faster.

@Test
public void testLargeFileIO_Scanner() throws Exception {

    long start = new Date().getTime();

    String fileName = "/Downloads/SampleTextFile_1000kb.txt"; //this path is on my local
    InputStream inputStream = new FileInputStream(fileName);

    try (Scanner fileScanner = new Scanner(inputStream, StandardCharsets.UTF_8.name())) {
        while (fileScanner.hasNextLine()) {
            String line = fileScanner.nextLine();
            //System.out.println(line);
        }
    }
    long end = new Date().getTime();

    long time = end - start;
    System.out.println("Scanner Time Consumed => " + time);

}


@Test
 public void testLargeFileIO_BufferedReader() throws Exception {

    long start = new Date().getTime();

    String fileName = "/Downloads/SampleTextFile_1000kb.txt"; //this path is on my local
    try (BufferedReader fileBufferReader = new BufferedReader(new FileReader(fileName))) {
        String fileLineContent;
        while ((fileLineContent = fileBufferReader.readLine()) != null) {
            //System.out.println(fileLineContent);
        }
    }
    long end = new Date().getTime();

    long time = (long) (end - start);
    System.out.println("BufferedReader Time Consumed => " + time);

}


@Test
public void testLargeFileIO_Stream() throws Exception {

    long start = new Date().getTime();

    String fileName = "/Downloads/SampleTextFile_1000kb.txt"; //this path is on my local
    try (Stream inputStream = Files.lines(Paths.get(fileName), StandardCharsets.UTF_8)) {
        //inputStream.forEach(System.out::println);
    }
    long end = new Date().getTime();

    long time = end - start;
    System.out.println("Stream Time Consumed => " + time);

}

What are projection and selection?

Projection: what ever typed in select clause i.e, 'column list' or '*' or 'expressions' that becomes under projection.

*selection:*what type of conditions we are applying on that columns i.e, getting the records that comes under selection.

For example:

  SELECT empno,ename,dno,job from Emp 
     WHERE job='CLERK'; 

in the above query the columns "empno,ename,dno,job" those comes under projection, "where job='clerk'" comes under selection

"Full screen" <iframe>

You can also use viewport-percentage lengths to achieve this:

5.1.2. Viewport-percentage lengths: the ‘vw’, ‘vh’, ‘vmin’, ‘vmax’ units

The viewport-percentage lengths are relative to the size of the initial containing block. When the height or width of the initial containing block is changed, they are scaled accordingly.

Where 100vh represents the height of the viewport, and likewise 100vw represents the width.

Example Here

_x000D_
_x000D_
body {_x000D_
    margin: 0;            /* Reset default margin */_x000D_
}_x000D_
iframe {_x000D_
    display: block;       /* iframes are inline by default */_x000D_
    background: #000;_x000D_
    border: none;         /* Reset default border */_x000D_
    height: 100vh;        /* Viewport-relative units */_x000D_
    width: 100vw;_x000D_
}
_x000D_
<iframe></iframe>
_x000D_
_x000D_
_x000D_

This is supported in most modern browsers - support can be found here.

How to prevent scientific notation in R?

Try format function:

> xx = 100000000000
> xx
[1] 1e+11
> format(xx, scientific=F)
[1] "100000000000"

ActionBarActivity: cannot be resolved to a type

Check if you have a android-support-v4.jar file in YOUR project's lib folder, it should be removed!

In the tutorial, when you have followed the instructions of Adding libraries WITHOUT resources before doing the coorect Adding libraries WITH resources you'll get the same error.

(Don't know why someone would do something like that *lookingawayfrommyself* ^^)

So what did fix it in my case, was removing the android-support-v4.jar from YOUR PROJECT (not the android-support-v7-appcompat project), since this caused some kind of library collision (maybe because in the meantime there was a new version of the suport library).

Just another case, when this error might shows up.

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

How does the SQL injection from the "Bobby Tables" XKCD comic work?

Let's say the name was used in a variable, $Name.

You then run this query:

INSERT INTO Students VALUES ( '$Name' )

The code is mistakenly placing anything the user supplied as the variable.

You wanted the SQL to be:

INSERT INTO Students VALUES ( 'Robert Tables` )

But a clever user can supply whatever they want:

INSERT INTO Students VALUES ( 'Robert'); DROP TABLE Students; --' )

What you get is:

INSERT INTO Students VALUES ( 'Robert' );  DROP TABLE STUDENTS; --' )

The -- only comments the remainder of the line.

Printing the correct number of decimal points with cout

setprecision(n) applies to the entire number, not the fractional part. You need to use the fixed-point format to make it apply to the fractional part: setiosflags(ios::fixed)

How to get the MD5 hash of a file in C++?

Here's a straight forward implementation of the md5sum command that computes and displays the MD5 of the file specified on the command-line. It needs to be linked against the OpenSSL library (gcc md5.c -o md5 -lssl) to work. It's pure C, but you should be able to adapt it to your C++ application easily enough.

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/md5.h>

unsigned char result[MD5_DIGEST_LENGTH];

// Print the MD5 sum as hex-digits.
void print_md5_sum(unsigned char* md) {
    int i;
    for(i=0; i <MD5_DIGEST_LENGTH; i++) {
            printf("%02x",md[i]);
    }
}

// Get the size of the file by its file descriptor
unsigned long get_size_by_fd(int fd) {
    struct stat statbuf;
    if(fstat(fd, &statbuf) < 0) exit(-1);
    return statbuf.st_size;
}

int main(int argc, char *argv[]) {
    int file_descript;
    unsigned long file_size;
    char* file_buffer;

    if(argc != 2) { 
            printf("Must specify the file\n");
            exit(-1);
    }
    printf("using file:\t%s\n", argv[1]);

    file_descript = open(argv[1], O_RDONLY);
    if(file_descript < 0) exit(-1);

    file_size = get_size_by_fd(file_descript);
    printf("file size:\t%lu\n", file_size);

    file_buffer = mmap(0, file_size, PROT_READ, MAP_SHARED, file_descript, 0);
    MD5((unsigned char*) file_buffer, file_size, result);
    munmap(file_buffer, file_size); 

    print_md5_sum(result);
    printf("  %s\n", argv[1]);

    return 0;
}

How do I use grep to search the current directory for all files having the a string "hello" yet display only .h and .cc files?

You can pass in wildcards in instead of specifying file names or using stdin.

grep hello *.h *.cc

How do I determine the size of my array in C?

Executive summary:

int a[17];
size_t n = sizeof(a)/sizeof(a[0]);

Full answer:

To determine the size of your array in bytes, you can use the sizeof operator:

int a[17];
size_t n = sizeof(a);

On my computer, ints are 4 bytes long, so n is 68.

To determine the number of elements in the array, we can divide the total size of the array by the size of the array element. You could do this with the type, like this:

int a[17];
size_t n = sizeof(a) / sizeof(int);

and get the proper answer (68 / 4 = 17), but if the type of a changed you would have a nasty bug if you forgot to change the sizeof(int) as well.

So the preferred divisor is sizeof(a[0]) or the equivalent sizeof(*a), the size of the first element of the array.

int a[17];
size_t n = sizeof(a) / sizeof(a[0]);

Another advantage is that you can now easily parameterize the array name in a macro and get:

#define NELEMS(x)  (sizeof(x) / sizeof((x)[0]))

int a[17];
size_t n = NELEMS(a);

How can I use random numbers in groovy?

For example, let's say that you want to create a random number between 50 and 60, you can use one of the following methods.

new Random().nextInt()%6 +55

new Random().nextInt()%6 returns a value between -5 and 5. and when you add it to 55 you can get values between 50 and 60

Second method:

Math.abs(new Random().nextInt()%11) +50

Math.abs(new Random().nextInt()%11) creates a value between 0 and 10. Later you can add 50 which in the will give you a value between 50 and 60

How to solve privileges issues when restore PostgreSQL Database

Use the postgres (admin) user to dump the schema, recreate it and grant priviledges for use before you do your restore. In one command:

sudo -u postgres psql -c "DROP SCHEMA public CASCADE;
create SCHEMA public;
grant usage on schema public to public;
grant create on schema public to public;" myDBName

Using FolderBrowserDialog in WPF application

You need to add a reference to System.Windows.Forms.dll, then use the System.Windows.Forms.FolderBrowserDialog class.

Adding using WinForms = System.Windows.Forms; will be helpful.

Save PL/pgSQL output from PostgreSQL to a CSV file

CSV Export Unification

This information isn't really well represented. As this is the second time I've needed to derive this, I'll put this here to remind myself if nothing else.

Really the best way to do this (get CSV out of postgres) is to use the COPY ... TO STDOUT command. Though you don't want to do it the way shown in the answers here. The correct way to use the command is:

COPY (select id, name from groups) TO STDOUT WITH CSV HEADER

Remember just one command!

It's great for use over ssh:

$ ssh psqlserver.example.com 'psql -d mydb "COPY (select id, name from groups) TO STDOUT WITH CSV HEADER"' > groups.csv

It's great for use inside docker over ssh:

$ ssh pgserver.example.com 'docker exec -tu postgres postgres psql -d mydb -c "COPY groups TO STDOUT WITH CSV HEADER"' > groups.csv

It's even great on the local machine:

$ psql -d mydb -c 'COPY groups TO STDOUT WITH CSV HEADER' > groups.csv

Or inside docker on the local machine?:

docker exec -tu postgres postgres psql -d mydb -c 'COPY groups TO STDOUT WITH CSV HEADER' > groups.csv

Or on a kubernetes cluster, in docker, over HTTPS??:

kubectl exec -t postgres-2592991581-ws2td 'psql -d mydb -c "COPY groups TO STDOUT WITH CSV HEADER"' > groups.csv

So versatile, much commas!

Do you even?

Yes I did, here are my notes:

The COPYses

Using /copy effectively executes file operations on whatever system the psql command is running on, as the user who is executing it1. If you connect to a remote server, it's simple to copy data files on the system executing psql to/from the remote server.

COPY executes file operations on the server as the backend process user account (default postgres), file paths and permissions are checked and applied accordingly. If using TO STDOUT then file permissions checks are bypassed.

Both of these options require subsequent file movement if psql is not executing on the system where you want the resultant CSV to ultimately reside. This is the most likely case, in my experience, when you mostly work with remote servers.

It is more complex to configure something like a TCP/IP tunnel over ssh to a remote system for simple CSV output, but for other output formats (binary) it may be better to /copy over a tunneled connection, executing a local psql. In a similar vein, for large imports, moving the source file to the server and using COPY is probably the highest-performance option.

PSQL Parameters

With psql parameters you can format the output like CSV but there are downsides like having to remember to disable the pager and not getting headers:

$ psql -P pager=off -d mydb -t -A -F',' -c 'select * from groups;'
2,Technician,Test 2,,,t,,0,,                                                                                                                                                                   
3,Truck,1,2017-10-02,,t,,0,,                                                                                                                                                                   
4,Truck,2,2017-10-02,,t,,0,,

Other Tools

No, I just want to get CSV out of my server without compiling and/or installing a tool.

datetime datatype in java

I used this import:

import java.util.Date;

And declared my variable like this:

Date studentEnrollementDate;

Problems with Android Fragment back stack

I had a similar issue where I had 3 consecutive fragments in the same Activity [M1.F0]->[M1.F1]->[M1.F2] followed by a call to a new Activity[M2]. If the user pressed a button in [M2] I wanted to return to [M1,F1] instead of [M1,F2] which is what back press behavior already did.

In order to accomplish this I remove [M1,F2], call show on [M1,F1], commit the transaction, and then add [M1,F2] back by calling it with hide. This removed the extra back press that would have otherwise been left behind.

// Remove [M1.F2] to avoid having an extra entry on back press when returning from M2
final FragmentTransaction ftA = fm.beginTransaction();
ftA.remove(M1F2Fragment);
ftA.show(M1F1Fragment);
ftA.commit();
final FragmentTransaction ftB = fm.beginTransaction();
ftB.hide(M1F2Fragment);
ftB.commit();

Hi After doing this code: I'm not able to see value of Fragment2 on pressing Back Key. My Code:

FragmentTransaction ft = fm.beginTransaction();
ft.add(R.id.frame, f1);
ft.remove(f1);

ft.add(R.id.frame, f2);
ft.addToBackStack(null);

ft.remove(f2);
ft.add(R.id.frame, f3);

ft.commit();

@Override
    public boolean onKeyDown(int keyCode, KeyEvent event){

        if(keyCode == KeyEvent.KEYCODE_BACK){
            Fragment currentFrag =  getFragmentManager().findFragmentById(R.id.frame);
            FragmentTransaction transaction = getFragmentManager().beginTransaction();

            if(currentFrag != null){
                String name = currentFrag.getClass().getName();
            }
            if(getFragmentManager().getBackStackEntryCount() == 0){
            }
            else{
                getFragmentManager().popBackStack();
                removeCurrentFragment();
            }
       }
    return super.onKeyDown(keyCode, event);
   }

public void removeCurrentFragment()
    {
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
        Fragment currentFrag =  getFragmentManager().findFragmentById(R.id.frame);

        if(currentFrag != null){
            transaction.remove(currentFrag);
        }
        transaction.commit();
    }

$_SERVER["REMOTE_ADDR"] gives server IP rather than visitor IP

Look no more for IP addresses not being set in the expected header. Just do the following to inspect the whole server variables and figure out which one is suitable for your case:

print_r($_SERVER);

Using array map to filter results with if conditional

You're looking for the .filter() function:

  $scope.appIds = $scope.applicationsHere.filter(function(obj) {
    return obj.selected;
  });

That'll produce an array that contains only those objects whose "selected" property is true (or truthy).

edit sorry I was getting some coffee and I missed the comments - yes, as jAndy noted in a comment, to filter and then pluck out just the "id" values, it'd be:

  $scope.appIds = $scope.applicationsHere.filter(function(obj) {
    return obj.selected;
  }).map(function(obj) { return obj.id; });

Some functional libraries (like Functional, which in my opinion doesn't get enough love) have a .pluck() function to extract property values from a list of objects, but native JavaScript has a pretty lean set of such tools.

Webpack.config how to just copy the index.html to the dist folder

I also found it easy and generic enough to put my index.html file in dist/ directory and add <script src='main.js'></script> to index.html to include my bundled webpack files. main.js seems to be default output name of our bundle if no other specified in webpack's conf file. I guess it's not good and long-term solution, but I hope it can help to understand how webpack works.

How to use a class object in C++ as a function parameter

holy errors The reason for the code below is to show how to not void main every function and not to type return; for functions...... instead push everything into the sediment for which is the print function prototype... if you need to use useful functions ... you will have to below..... (p.s. this below is for people overwhelmed by these object and T templates which allow different variable declaration types(such as float and char) to use the same passed by value in a user defined function)

char arr[ ] = "This is a test";

string str(arr);


//  You can also assign directly to a string.
str = "This is another string";

can anyone tell me why c++ made arrays into pass by value one at a time and the only way to eliminate spaces and punctuation is the use of string tokens. I couldn't get around the problem when i was trying to delete spaces for a palindrome...

#include <iostream>
#include <iomanip>
using namespace std;
int getgrades(float[]);
int getaverage(float[], float);
int calculateletters(float[], float, float, float[]);
int printResults(float[], float, float, float[]);


int main()
{

int i;
float  maxSize=3, size;
float  lettergrades[5], numericgrades[100], average;

size=getgrades(numericgrades);
average = getaverage(numericgrades, size);
printResults(numericgrades, size, average, lettergrades);
return 0;
}

int getgrades(float a[])
{ 


int i, max=3;

for (i = 0; i <max; i++)
{
    //ask use for input
    cout << "\nPlease Enter grade " << i+1 << " : ";
    cin >> a[i];
    //makes sure that user enters a vlue between 0 and 100

   if(a[i] < 0 || a[i] >100)
    {
        cout << "Wrong input. Please
 enter a value between 0 and 100 only." << endl;
        cout << "\nPlease Reenter grade " << i+1 << " : ";
        cin >> a[i];

        return i;
    }
}
}

int getaverage(float a[], float n) 
{ 
int i;
float sum = 0;
 if (n == 0)
return 0;
for (i = 0; i < n; i++)
sum += a[i];
return sum / n;
}                               


int printResults(float a[], float n, float average, float letters[]) 
{
int i;
cout << "Index Number | input  |
array values address in memory " << endl;

for (i = 0; i < 3; i++)
{
cout <<"     "<< i<<" \t\t"<<setprecision(3)<<
a[i]<<"\t\t" << &a[i] << endl;
}
cout<<"The average of your grades is: "<<setprecision(3)<<average<<endl;

}

psql: server closed the connection unexepectedly

In my case I was making an connection through pgAdmin with ssh tunneling and set to host field ip address but it was necessary to set localhost

LaTeX "\indent" creating paragraph indentation / tabbing package requirement?

This is kind of a hack but the best solution that I have found is to use a description tag with no \item. This will produce an error from the latex compiler; however, the error does not prevent the pdf from being generated.

\begin{description} 
     <YOUR TEXT HERE> 
\end{description}
  • This only worked on windows latex compiler

Simple and fast method to compare images for similarity

Does the screenshot contain only the icon? If so, the L2 distance of the two images might suffice. If the L2 distance doesn't work, the next step is to try something simple and well established, like: Lucas-Kanade. Which I'm sure is available in OpenCV.

printf not printing on console

  1. In your project folder, create a “.gdbinit” text file. It will contain your gdb debugger configuration
  2. Edit “.gdbinit”, and add the line (without the quotes) : “set new-console on”
  3. After building the project right click on the project Debug > “Debug Configurations”, as shown below Debug configuration

  4. In the “debugger” tab, ensure the “GDB command file” now points to your “.gdbinit” file. Else, input the path to your “.gdbinit” configuration file : Gdb configuration

  5. Click “Apply” and “Debug”. A native DOS command line should be launched as shown below Console

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

I like user64141's answer but found that it could be more generalized. Here's my take:

public abstract class ExpectedThrowableAsserter implements Runnable {

    private final Class<? extends Throwable> throwableClass;
    private final String expectedExceptionMessage;

    protected ExpectedThrowableAsserter(Class<? extends Throwable> throwableClass, String expectedExceptionMessage) {
        this.throwableClass = throwableClass;
        this.expectedExceptionMessage = expectedExceptionMessage;
    }

    public final void run() {
        try {
            expectException();
        } catch (Throwable e) {
            assertTrue(String.format("Caught unexpected %s", e.getClass().getSimpleName()), throwableClass.isInstance(e));
            assertEquals(String.format("%s caught, but unexpected message", throwableClass.getSimpleName()), expectedExceptionMessage, e.getMessage());
            return;
        }
        fail(String.format("Expected %s, but no exception was thrown.", throwableClass.getSimpleName()));
    }

    protected abstract void expectException();

}

Note that leaving the "fail" statement within the try block causes the related assertion exception to be caught; using return within the catch statement prevents this.

android.os.NetworkOnMainThreadException with android 4.2

This is the correct way:

public class JSONParser extends AsyncTask <String, Void, String>{

    static InputStream is = null;

static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}
@Override
protected String doInBackground(String... params) {


    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet httpPost = new HttpGet(url);

            HttpResponse getResponse = httpClient.execute(httpPost);
           final int statusCode = getResponse.getStatusLine().getStatusCode();

           if (statusCode != HttpStatus.SC_OK) { 
              Log.w(getClass().getSimpleName(), 
                  "Error " + statusCode + " for URL " + url); 
              return null;
           }

           HttpEntity getResponseEntity = getResponse.getEntity();

        //HttpResponse httpResponse = httpClient.execute(httpPost);
        //HttpEntity httpEntity = httpResponse.getEntity();
        is = getResponseEntity.getContent();            

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        Log.d("IO", e.getMessage().toString());
        e.printStackTrace();

    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;


}
protected void onPostExecute(String page)
{   
    //onPostExecute
}   
}

To call it (from main):

mJSONParser = new JSONParser();
mJSONParser.execute();

Jackson serialization: ignore empty values (or null)

Or you can use GSON [https://code.google.com/p/google-gson/], where these null fields will be automatically removed.

SampleDTO.java

public class SampleDTO {

    String username;
    String email;
    String password;
    String birthday;
    String coinsPackage;
    String coins;
    String transactionId;
    boolean isLoggedIn;

    // getters/setters
}

Test.java

import com.google.gson.Gson;

public class Test {

    public static void main(String[] args) {
        SampleDTO objSampleDTO = new SampleDTO();
        Gson objGson = new Gson();
        System.out.println(objGson.toJson(objSampleDTO));
    }
}

OUTPUT:

{"isLoggedIn":false}

I used gson-2.2.4

The best node module for XML parsing

This answer concerns developers for Windows. You want to pick an XML parsing module that does NOT depend on node-expat. Node-expat requires node-gyp and node-gyp requires you to install Visual Studio on your machine. If your machine is a Windows Server, you definitely don't want to install Visual Studio on it.

So, which XML parsing module to pick?

Save yourself a lot of trouble and use either xml2js or xmldoc. They depend on sax.js which is a pure Javascript solution that doesn't require node-gyp.

Both libxmljs and xml-stream require node-gyp. Don't pick these unless you already have Visual Studio on your machine installed or you don't mind going down that road.

Update 2015-10-24: it seems somebody found a solution to use node-gyp on Windows without installing VS: https://github.com/nodejs/node-gyp/issues/629#issuecomment-138276692

jQuery .find() on data from .ajax() call is returning "[object Object]" instead of div

The thing is that your ajax response is returning a string, so if you use directly $(response) it would return JQUERY: Uncaught Error: Syntax error, unrecognized expression in the console. In order to use it properly you need to use first a JQUERY built-in function called $.parseHTML(response). As what the function name implies you need to parse the string first as an html object. Just like this in your case:

$.ajax({
    url: url, 
    cache: false,
    success: function(response) {
        var parsedResponse = $.parseHTML(response);
        var result = $(parsedResponse).find("#result");

        alert(response); // returns as string in console
        alert(parsedResponse); // returns as object HTML in console
        alert(result); // returns as object that has an id named result 
    }
});

How to change JDK version for an Eclipse project

If you are using maven build tool then add the below properties to it and doing a maven update will solve the problem

<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>

Imported a csv-dataset to R but the values becomes factors

None of these answers mention the colClasses argument which is another way to specify the variable classes in read.csv.

 stuckey <- read.csv("C:/kalle/R/stuckey.csv", colClasses = "numeric") # all variables to numeric

or you can specify which columns to convert:

stuckey <- read.csv("C:/kalle/R/stuckey.csv", colClasses = c("PTS" = "numeric", "MP" = "numeric") # specific columns to numeric

Note that if a variable can't be converted to numeric then it will be converted to factor as default which makes it more difficult to convert to number. Therefore, it can be advisable just to read all variables in as 'character' colClasses = "character" and then convert the specific columns to numeric once the csv is read in:

stuckey <- read.csv("C:/kalle/R/stuckey.csv", colClasses = "character")
point <- as.numeric(stuckey$PTS)
time <- as.numeric(stuckey$MP)

How do I move a file from one location to another in Java?

Try this :-

  boolean success = file.renameTo(new File(Destdir, file.getName()));

How to copy data from one HDFS to another HDFS?

Hadoop comes with a useful program called distcp for copying large amounts of data to and from Hadoop Filesystems in parallel. The canonical use case for distcp is for transferring data between two HDFS clusters. If the clusters are running identical versions of hadoop, then the hdfs scheme is appropriate to use.

$ hadoop distcp hdfs://namenode1/foo hdfs://namenode2/bar

The data in /foo directory of namenode1 will be copied to /bar directory of namenode2. If the /bar directory does not exist, it will create it. Also we can mention multiple source paths.

Similar to rsync command, distcp command by default will skip the files that already exist. We can also use -overwrite option to overwrite the existing files in destination directory. The option -update will only update the files that have changed.

$ hadoop distcp -update hdfs://namenode1/foo hdfs://namenode2/bar/foo

distcp can also be implemented as a MapReduce job where the work of copying is done by the maps that run in parallel across the cluster. There will be no reducers.

If trying to copy data between two HDFS clusters that are running different versions, the copy will process will fail, since the RPC systems are incompatible. In that case we need to use the read-only HTTP based HFTP filesystems to read from the source. Here the job has to run on destination cluster.

$ hadoop distcp hftp://namenode1:50070/foo hdfs://namenode2/bar

50070 is the default port number for namenode's embedded web server.

How to get the values of a ConfigurationSection of type NameValueSectionHandler

Here are some examples from this blog mentioned earlier:

<configuration>    
   <Database>    
      <add key="ConnectionString" value="data source=.;initial catalog=NorthWind;integrated security=SSPI"/>    
   </Database>    
</configuration>  

get values:

 NameValueCollection db = (NameValueCollection)ConfigurationSettings.GetConfig("Database");         
    labelConnection2.Text = db["ConnectionString"];

-

Another example:

<Locations 
   ImportDirectory="C:\Import\Inbox"
   ProcessedDirectory ="C:\Import\Processed"
   RejectedDirectory ="C:\Import\Rejected"
/>

get value:

Hashtable loc = (Hashtable)ConfigurationSettings.GetConfig("Locations"); 

labelImport2.Text = loc["ImportDirectory"].ToString();
labelProcessed2.Text = loc["ProcessedDirectory"].ToString();

Declaring variable workbook / Worksheet vba

I had the same issue. I used Worksheet instead of Worksheets and it was resolved. Not sure what the difference is between them.

Thread Safe C# Singleton Pattern

The Lazy<T> version:

public sealed class Singleton
{
    private static readonly Lazy<Singleton> lazy
        = new Lazy<Singleton>(() => new Singleton());

    public static Singleton Instance
        => lazy.Value;

    private Singleton() { }
}

Requires .NET 4 and C# 6.0 (VS2015) or newer.

set pythonpath before import statements

As also noted in the docs here.
Go to Python X.X/Lib and add these lines to the site.py there,

import sys
sys.path.append("yourpathstring")

This changes your sys.path so that on every load, it will have that value in it..

As stated here about site.py,

This module is automatically imported during initialization. Importing this module will append site-specific paths to the module search path and add a few builtins.

For other possible methods of adding some path to sys.path see these docs

Pylint, PyChecker or PyFlakes?

pep8 was recently added to PyPi.

  • pep8 - Python style guide checker
  • pep8 is a tool to check your Python code against some of the style conventions in PEP 8.

It is now super easy to check your code against pep8.

See http://pypi.python.org/pypi/pep8

Simulate a specific CURL in PostMan

As mentioned in multiple answers above you can import the cURL in POSTMAN directly. But if URL is authorized (or is not working for some reason) ill suggest you can manually add all the data points as JSON in your postman body. take the API URL from the cURL.

for the Authorization part- just add an Authorization key and base 64 encoded string as value.

example:

curl -u rzp_test_26ccbdbfe0e84b:69b2e24411e384f91213f22a \ https://api.razorpay.com/v1/orders -X POST \ --data "amount=50000" \ --data "currency=INR" \ --data "receipt=Receipt #20" \ --data "payment_capture=1" https://api.razorpay.com/v1/orders

{ "amount": "5000", "currency": "INR", "receipt": "Receipt #20", "payment_capture": "1" }

Headers: Authorization:Basic cnpwX3Rlc3RfWEk5QW5TU0N3RlhjZ0Y6dURjVThLZ3JiQVVnZ3JNS***U056V25J where "cnpwX3Rlc3RfWEk5QW5TU0N3RlhjZ0Y6dURjVThLZ3JiQVVnZ3JNS***U056V25J" is the encoded form of "rzp_test_26ccbdbfe0e84b:69b2e24411e384f91213f22a"`

small tip: for encoding, you can easily go to your chrome console (right-click => inspect) and type : btoa("string you want to encode") ( or use postman basic authorization)

round value to 2 decimals javascript

If you want it visually formatted to two decimals as a string (for output) use toFixed():

var priceString = someValue.toFixed(2);

The answer by @David has two problems:

  1. It leaves the result as a floating point number, and consequently holds the possibility of displaying a particular result with many decimal places, e.g. 134.1999999999 instead of "134.20".

  2. If your value is an integer or rounds to one tenth, you will not see the additional decimal value:

    var n = 1.099;
    (Math.round( n * 100 )/100 ).toString() //-> "1.1"
    n.toFixed(2)                            //-> "1.10"
    
    var n = 3;
    (Math.round( n * 100 )/100 ).toString() //-> "3"
    n.toFixed(2)                            //-> "3.00"
    

And, as you can see above, using toFixed() is also far easier to type. ;)

Java JSON serialization - best practice

Well, when writing it out to file, you do know what class T is, so you can store that in dump. Then, when reading it back in, you can dynamically call it using reflection.

public JSONObject dump() throws JSONException {
    JSONObject result = new JSONObject();
    JSONArray a = new JSONArray();
    for(T i : items){
        a.put(i.dump());
        // inside this i.dump(), store "class-name"
    }
    result.put("items", a);
    return result;
}

public void load(JSONObject obj) throws JSONException {
    JSONArray arrayItems = obj.getJSONArray("items");
    for (int i = 0; i < arrayItems.length(); i++) {
        JSONObject item = arrayItems.getJSONObject(i);
        String className = item.getString("class-name");
        try {
            Class<?> clazzy = Class.forName(className);
            T newItem = (T) clazzy.newInstance();
            newItem.load(obj);
            items.add(newItem);
        } catch (InstantiationException e) {
            // whatever
        } catch (IllegalAccessException e) {
            // whatever
        } catch (ClassNotFoundException e) {
            // whatever
        }
    }

What is the backslash character (\\)?

\ is used as for escape sequence in many programming languages, including Java.

If you want to

  • go to next line then use \n or \r,
  • for tab use \t
  • likewise to print a \ or " which are special in string literal you have to escape it with another \ which gives us \\ and \"

Why does ASP.NET webforms need the Runat="Server" attribute?

I just came to this conclusion by trial-and-error: runat="server" is needed to access the elements at run-time on server side. Remove them, recompile and watch what happens.

asterisk : Unable to connect to remote asterisk (does /var/run/asterisk.ctl exist?)

I have just installed asterisk 13.18.5 on CentOS7. After logging in as root, I was having the same problem and I just did "SELINUX=disabled" in /var/selinux/config and that was all. My asterisk started in verbose mode by doing asterisk -rvvvvvv. No errors !!!

Another way to get it done is to use "asterisk -&" command first and then wait for a while for an "OK" message from asterisk and then "asterisk -rvvvvv"

Can a relative sitemap url be used in a robots.txt?

According to the official documentation on sitemaps.org it needs to be a full URL:

You can specify the location of the Sitemap using a robots.txt file. To do this, simply add the following line including the full URL to the sitemap:

Sitemap: http://www.example.com/sitemap.xml