Programs & Examples On #Search box

A search box or search field is a common GUI element used in computer programs

Add Twitter Bootstrap icon to Input box

For bootstrap 4

        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

            <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
            <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
            <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
        <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet">
        <form class="form-inline my-2 my-lg-0">
                        <div class="input-group">
                            <input class="form-control" type="search" placeholder="Search">
                            <div class="input-group-append">
                                <div class="input-group-text"><i class="fa fa-search"></i></div>
                            </div>
                        </div>
                    </form>

Demo

Giving multiple URL patterns to Servlet Filter

In case you are using the annotation method for filter definition (as opposed to defining them in the web.xml), you can do so by just putting an array of mappings in the @WebFilter annotation:

/**
 * Filter implementation class LoginFilter
 */
@WebFilter(urlPatterns = { "/faces/Html/Employee","/faces/Html/Admin", "/faces/Html/Supervisor"})
public class LoginFilter implements Filter {
    ...

And just as an FYI, this same thing works for servlets using the servlet annotation too:

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet({"/faces/Html/Employee", "/faces/Html/Admin", "/faces/Html/Supervisor"})
public class LoginServlet extends HttpServlet {
    ...

AngularJS - Trigger when radio button is selected

Should use ngChange instead of ngClick if trigger source is not from click.

Is the below what you want ? what exactly doesn't work in your case ?

var myApp = angular.module('myApp', []);

function MyCtrl($scope) {
    $scope.value = "none" ;
    $scope.isChecked = false;
    $scope.checkStuff = function () {
        $scope.isChecked = !$scope.isChecked;
    }
}


<div ng-controller="MyCtrl">
    <input type="radio" ng-model="value" value="one" ng-change="checkStuff()" />
    <span> {{value}} isCheck:{{isChecked}} </span>
</div>   

How to set HTML5 required attribute in Javascript?

try out this..

document.getElementById("edName").required = true;

Apache - MySQL Service detected with wrong path. / Ports already in use

This is how I solved similar problem:

  1. Launch XAMPP Control Panel.
  2. Uninstall the MySQL service: click 'green check' button beside MySQL, under Service column. The 'green check' button will change into 'red cross' button.
  3. Exit XAMPP, and relaunch it again.
  4. Click Start.

I hope it can help solve your problem too.

XAMPP MySQL password setting (Can not enter in PHPMYADMIN)

Find the below code in xampp/phpmyadmin/config.inc.php

$cfg['Servers'][$i]['controluser']  = 'user_name/root';   
$cfg['Servers'][$i]['controlpass']  = 'passwaord';
$cfg['Servers'][$i]['auth_type']    = 'config';
$cfg['Servers'][$i]['user']         = 'user_name/root';
$cfg['Servers'][$i]['password']     = 'password';

Replace each statement above with the corresponding entry below:

$cfg['Servers'][$i]['controluser']  = 'root';   
$cfg['Servers'][$i]['controlpass']  = 'xxxx';
$cfg['Servers'][$i]['auth_type']    = 'config';
$cfg['Servers'][$i]['user']         = 'root';
$cfg['Servers'][$i]['password']     = 'xxxx';

Doing this caused localhost/phpmyadmin in the browser and the MySQL command prompt to work properly.

jquery - Click event not working for dynamically created button

You create buttons dynamically because of that you need to call them with .live() method if you use jquery 1.7

but this method is deprecated (you can see the list of all deprecated method here) in newer version. if you want to use jquery 1.10 or above you need to call your buttons in this way:

$(document).on('click', 'selector', function(){ 
     // Your Code
});

For Example

If your html is something like this

<div id="btn-list">
    <div class="btn12">MyButton</div>
</div>

You can write your jquery like this

$(document).on('click', '#btn-list .btn12', function(){ 
     // Your Code
});

How to resolve "could not execute statement; SQL [n/a]; constraint [numbering];"?

The solution at my end was to explicitly add a JoinColumn annotation like this:

@JoinColumn(name="mapping_type_id")

The column name is usually the table name + "_id" if there is an id field. Additionally, keep in mind which field it should be based on the relationship, OneToMany or ManyToOne.

Hope this helps.

Java Delegates?

I have implemented callback/delegate support in Java using reflection. Details and working source are available on my website.

How It Works

There is a principle class named Callback with a nested class named WithParms. The API which needs the callback will take a Callback object as a parameter and, if neccessary, create a Callback.WithParms as a method variable. Since a great many of the applications of this object will be recursive, this works very cleanly.

With performance still a high priority to me, I didn't want to be required to create a throwaway object array to hold the parameters for every invocation - after all in a large data structure there could be thousands of elements, and in a message processing scenario we could end up processing thousands of data structures a second.

In order to be threadsafe the parameter array needs to exist uniquely for each invocation of the API method, and for efficiency the same one should be used for every invocation of the callback; I needed a second object which would be cheap to create in order to bind the callback with a parameter array for invocation. But, in some scenarios, the invoker would already have a the parameter array for other reasons. For these two reasons, the parameter array does not belong in the Callback object. Also the choice of invocation (passing the parameters as an array or as individual objects) belongs in the hands of the API using the callback enabling it to use whichever invocation is best suited to its inner workings.

The WithParms nested class, then, is optional and serves two purposes, it contains the parameter object array needed for the callback invocations, and it provides 10 overloaded invoke() methods (with from 1 to 10 parameters) which load the parameter array and then invoke the callback target.

What follows is an example using a callback to process the files in a directory tree. This is an initial validation pass which just counts the files to process and ensure none exceed a predetermined maximum size. In this case we just create the callback inline with the API invocation. However, we reflect the target method out as a static value so that the reflection is not done every time.

static private final Method             COUNT =Callback.getMethod(Xxx.class,"callback_count",true,File.class,File.class);

...

IoUtil.processDirectory(root,new Callback(this,COUNT),selector);

...

private void callback_count(File dir, File fil) {
    if(fil!=null) {                                                                             // file is null for processing a directory
        fileTotal++;
        if(fil.length()>fileSizeLimit) {
            throw new Abort("Failed","File size exceeds maximum of "+TextUtil.formatNumber(fileSizeLimit)+" bytes: "+fil);
            }
        }
    progress("Counting",dir,fileTotal);
    }

IoUtil.processDirectory():

/**
 * Process a directory using callbacks.  To interrupt, the callback must throw an (unchecked) exception.
 * Subdirectories are processed only if the selector is null or selects the directories, and are done
 * after the files in any given directory.  When the callback is invoked for a directory, the file
 * argument is null;
 * <p>
 * The callback signature is:
 * <pre>    void callback(File dir, File ent);</pre>
 * <p>
 * @return          The number of files processed.
 */
static public int processDirectory(File dir, Callback cbk, FileSelector sel) {
    return _processDirectory(dir,new Callback.WithParms(cbk,2),sel);
    }

static private int _processDirectory(File dir, Callback.WithParms cbk, FileSelector sel) {
    int                                 cnt=0;

    if(!dir.isDirectory()) {
        if(sel==null || sel.accept(dir)) { cbk.invoke(dir.getParent(),dir); cnt++; }
        }
    else {
        cbk.invoke(dir,(Object[])null);

        File[] lst=(sel==null ? dir.listFiles() : dir.listFiles(sel));
        if(lst!=null) {
            for(int xa=0; xa<lst.length; xa++) {
                File ent=lst[xa];
                if(!ent.isDirectory()) {
                    cbk.invoke(dir,ent);
                    lst[xa]=null;
                    cnt++;
                    }
                }
            for(int xa=0; xa<lst.length; xa++) {
                File ent=lst[xa];
                if(ent!=null) { cnt+=_processDirectory(ent,cbk,sel); }
                }
            }
        }
    return cnt;
    }

This example illustrates the beauty of this approach - the application specific logic is abstracted into the callback, and the drudgery of recursively walking a directory tree is tucked nicely away in a completely reusable static utility method. And we don't have to repeatedly pay the price of defining and implementing an interface for every new use. Of course, the argument for an interface is that it is far more explicit about what to implement (it's enforced, not simply documented) - but in practice I have not found it to be a problem to get the callback definition right.

Defining and implementing an interface is not really so bad (unless you're distributing applets, as I am, where avoiding creating extra classes actually matters), but where this really shines is when you have multiple callbacks in a single class. Not only is being forced to push them each into a separate inner class added overhead in the deployed application, but it's downright tedious to program and all that boiler-plate code is really just "noise".

map function for objects (instead of arrays)

To responds more closely to what precisely the OP asked for, the OP wants an object:

myObject = { 'a': 1, 'b': 2, 'c': 3 }

to have a map method myObject.map,

similar to Array.prototype.map that would be used as follows:

newObject = myObject.map(function (value, label) {
    return value * value;
});
// newObject is now { 'a': 1, 'b': 4, 'c': 9 }

The imho best (measured in terms to "close to what is asked" + "no ES{5,6,7} required needlessly") answer would be:

myObject.map = function mapForObject(callback)
{
  var result = {};
  for(var property in this){
    if(this.hasOwnProperty(property) && property != "map"){
      result[property] = callback(this[property],property,this);
    }
  }
  return result;
}

The code above avoids intentionally using any language features, only available in recent ECMAScript editions. With the code above the problem can be solved lke this:

_x000D_
_x000D_
myObject = { 'a': 1, 'b': 2, 'c': 3 };_x000D_
_x000D_
myObject.map = function mapForObject(callback)_x000D_
{_x000D_
  var result = {};_x000D_
  for(var property in this){_x000D_
    if(this.hasOwnProperty(property) && property != "map"){_x000D_
      result[property] = callback(this[property],property,this);_x000D_
    }_x000D_
  }_x000D_
  return result;_x000D_
}_x000D_
_x000D_
newObject = myObject.map(function (value, label) {_x000D_
  return value * value;_x000D_
});_x000D_
console.log("newObject is now",newObject);
_x000D_
_x000D_
_x000D_ alternative test code here

Besides frowned upon by some, it would be a possibility to insert the solution in the prototype chain like this.

Object.prototype.map = function(callback)
{
  var result = {};
  for(var property in this){
    if(this.hasOwnProperty(property)){
      result[property] = callback(this[property],property,this);
    }
  }
  return result;
}

Something, which when done with careful oversight should not have any ill effects and not impact map method of other objects (i.e. Array's map).

@property retain, assign, copy, nonatomic in Objective-C

The article linked to by MrMage is no longer working. So, here is what I've learned in my (very) short time coding in Objective-C:

nonatomic vs. atomic - "atomic" is the default. Always use "nonatomic". I don't know why, but the book I read said there is "rarely a reason" to use "atomic". (BTW: The book I read is the BNR "iOS Programming" book.)

readwrite vs. readonly - "readwrite" is the default. When you @synthesize, both a getter and a setter will be created for you. If you use "readonly", no setter will be created. Use it for a value you don't want to ever change after the instantiation of the object.

retain vs. copy vs. assign

  • "assign" is the default. In the setter that is created by @synthesize, the value will simply be assigned to the attribute. My understanding is that "assign" should be used for non-pointer attributes.
  • "retain" is needed when the attribute is a pointer to an object. The setter generated by @synthesize will retain (aka add a retain count) the object. You will need to release the object when you are finished with it.
  • "copy" is needed when the object is mutable. Use this if you need the value of the object as it is at this moment, and you don't want that value to reflect any changes made by other owners of the object. You will need to release the object when you are finished with it because you are retaining the copy.

How to send a “multipart/form-data” POST in Android with Volley

Here is Simple Solution And Complete Example for Uploading File Using Volley Android

1) Gradle Import

compile 'dev.dworks.libs:volleyplus:+'

2)Now Create a Class RequestManager

public class RequestManager {
    private static RequestManager mRequestManager;
    /**
     * Queue which Manages the Network Requests :-)
     */
    private static RequestQueue mRequestQueue;
    // ImageLoader Instance

    private RequestManager() {

    }

    public static RequestManager get(Context context) {

        if (mRequestManager == null)
            mRequestManager = new RequestManager();

        return mRequestManager;
    }

    /**
     * @param context application context
     */
    public static RequestQueue getnstance(Context context) {

        if (mRequestQueue == null) {
            mRequestQueue = Volley.newRequestQueue(context);
        }

        return mRequestQueue;

    }


}

3)Now Create a Class to handle Request for uploading File WebService

public class WebService {
    private RequestQueue mRequestQueue;
    private static WebService apiRequests = null;

    public static WebService getInstance() {
        if (apiRequests == null) {
            apiRequests = new WebService();
            return apiRequests;
        }
        return apiRequests;
    }
    public void updateProfile(Context context, String doc_name, String doc_type, String appliance_id, File file, Response.Listener<String> listener, Response.ErrorListener errorListener) {
        SimpleMultiPartRequest request = new SimpleMultiPartRequest(Request.Method.POST, "YOUR URL HERE", listener, errorListener);
//        request.setParams(data);
        mRequestQueue = RequestManager.getnstance(context);
        request.addMultipartParam("token", "text", "tdfysghfhsdfh");
        request.addMultipartParam("parameter_1", "text", doc_name);
        request.addMultipartParam("dparameter_2", "text", doc_type);
        request.addMultipartParam("parameter_3", "text", appliance_id);
            request.addFile("document_file", file.getPath());

        request.setFixedStreamingMode(true);
        mRequestQueue.add(request);
    }
}

4) And Now Call The method Like This to Hit the service

public class Main2Activity extends AppCompatActivity implements Response.ErrorListener, Response.Listener<String>{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Button button=(Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                uploadData();
            }
        });
    }

    private void uploadData() {
        WebService.getInstance().updateProfile(getActivity(), "appl_doc", "appliance", "1", mChoosenFile, this, this);
    }

    @Override
    public void onErrorResponse(VolleyError error) {

    }

    @Override
    public void onResponse(String response) {
     //Your response here 
    }
}

How do you read scanf until EOF in C?

Man, if you are using Windows, EOF is not reached by pressing enter, but by pressing Crtl+Z at the console. This will print "^Z", an indicator of EOF. The behavior of functions when reading this (the EOF or Crtl+Z):

Function: Output: scanf(...) EOF gets(<variable>) NULL feof(stdin) 1 getchar() EOF

How can we store into an NSDictionary? What is the difference between NSDictionary and NSMutableDictionary?

The key difference: NSMutableDictionary can be modified in place, NSDictionary cannot. This is true for all the other NSMutable* classes in Cocoa. NSMutableDictionary is a subclass of NSDictionary, so everything you can do with NSDictionary you can do with both. However, NSMutableDictionary also adds complementary methods to modify things in place, such as the method setObject:forKey:.

You can convert between the two like this:

NSMutableDictionary *mutable = [[dict mutableCopy] autorelease];
NSDictionary *dict = [[mutable copy] autorelease]; 

Presumably you want to store data by writing it to a file. NSDictionary has a method to do this (which also works with NSMutableDictionary):

BOOL success = [dict writeToFile:@"/file/path" atomically:YES];

To read a dictionary from a file, there's a corresponding method:

NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:@"/file/path"];

If you want to read the file as an NSMutableDictionary, simply use:

NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithContentsOfFile:@"/file/path"];

Sending message through WhatsApp

The following code is used by Google Now App and will NOT work for any other application.

I'm writing this post because it makes me angry, that WhatsApp does not allow any other developers to send messages directly except for Google.

And I want other freelance-developers to know, that this kind of cooperation is going on, while Google keeps talking about "open for anybody" and WhatsApp says they don't want to provide any access to developers.

Recently WhatsApp has added an Intent specially for Google Now, which should look like following:

Intent intent = new Intent("com.google.android.voicesearch.SEND_MESSAGE_TO_CONTACTS");
intent.setPackage("com.whatsapp");
intent.setComponent(new ComponentName("com.whatsapp", "com.whatsapp.VoiceMessagingActivity"));

intent.putExtra("com.google.android.voicesearch.extra.RECIPIENT_CONTACT_CHAT_ID", number);
intent.putExtra("android.intent.extra.TEXT", text);
intent.putExtra("search_action_token", ?????);

I could also find out that "search_action_token" is a PendingIntent that contains an IBinder-Object, which is sent back to Google App and checked, if it was created by Google Now.

Otherwise WhatsApp will not accept the message.

Getting request URL in a servlet

The getRequestURL() omits the port when it is 80 while the scheme is http, or when it is 443 while the scheme is https.

So, just use getRequestURL() if all you want is obtaining the entire URL. This does however not include the GET query string. You may want to construct it as follows then:

StringBuffer requestURL = request.getRequestURL();
if (request.getQueryString() != null) {
    requestURL.append("?").append(request.getQueryString());
}
String completeURL = requestURL.toString();

What does T&& (double ampersand) mean in C++11?

It denotes an rvalue reference. Rvalue references will only bind to temporary objects, unless explicitly generated otherwise. They are used to make objects much more efficient under certain circumstances, and to provide a facility known as perfect forwarding, which greatly simplifies template code.

In C++03, you can't distinguish between a copy of a non-mutable lvalue and an rvalue.

std::string s;
std::string another(s);           // calls std::string(const std::string&);
std::string more(std::string(s)); // calls std::string(const std::string&);

In C++0x, this is not the case.

std::string s;
std::string another(s);           // calls std::string(const std::string&);
std::string more(std::string(s)); // calls std::string(std::string&&);

Consider the implementation behind these constructors. In the first case, the string has to perform a copy to retain value semantics, which involves a new heap allocation. However, in the second case, we know in advance that the object which was passed in to our constructor is immediately due for destruction, and it doesn't have to remain untouched. We can effectively just swap the internal pointers and not perform any copying at all in this scenario, which is substantially more efficient. Move semantics benefit any class which has expensive or prohibited copying of internally referenced resources. Consider the case of std::unique_ptr- now that our class can distinguish between temporaries and non-temporaries, we can make the move semantics work correctly so that the unique_ptr cannot be copied but can be moved, which means that std::unique_ptr can be legally stored in Standard containers, sorted, etc, whereas C++03's std::auto_ptr cannot.

Now we consider the other use of rvalue references- perfect forwarding. Consider the question of binding a reference to a reference.

std::string s;
std::string& ref = s;
(std::string&)& anotherref = ref; // usually expressed via template

Can't recall what C++03 says about this, but in C++0x, the resultant type when dealing with rvalue references is critical. An rvalue reference to a type T, where T is a reference type, becomes a reference of type T.

(std::string&)&& ref // ref is std::string&
(const std::string&)&& ref // ref is const std::string&
(std::string&&)&& ref // ref is std::string&&
(const std::string&&)&& ref // ref is const std::string&&

Consider the simplest template function- min and max. In C++03 you have to overload for all four combinations of const and non-const manually. In C++0x it's just one overload. Combined with variadic templates, this enables perfect forwarding.

template<typename A, typename B> auto min(A&& aref, B&& bref) {
    // for example, if you pass a const std::string& as first argument,
    // then A becomes const std::string& and by extension, aref becomes
    // const std::string&, completely maintaining it's type information.
    if (std::forward<A>(aref) < std::forward<B>(bref))
        return std::forward<A>(aref);
    else
        return std::forward<B>(bref);
}

I left off the return type deduction, because I can't recall how it's done offhand, but that min can accept any combination of lvalues, rvalues, const lvalues.

How to split strings over multiple lines in Bash?

I came across a situation in which I had to send a long message as part of a command argument and had to adhere to the line length limitation. The commands looks something like this:

somecommand --message="I am a long message" args

The way I solved this is to move the message out as a here document (like @tripleee suggested). But a here document becomes a stdin, so it needs to be read back in, I went with the below approach:

message=$(
    tr "\n" " " <<- END
        This is a
        long message
END
)
somecommand --message="$message" args

This has the advantage that $message can be used exactly as the string constant with no extra whitespace or line breaks.

Note that the actual message lines above are prefixed with a tab character each, which is stripped by here document itself (because of the use of <<-). There are still line breaks at the end, which are then replaced by dd with spaces.

Note also that if you don't remove newlines, they will appear as is when "$message" is expanded. In some cases, you may be able to workaround by removing the double-quotes around $message, but the message will no longer be a single argument.

What does it mean to inflate a view from an xml file?

"Inflating" a view means taking the layout XML and parsing it to create the view and viewgroup objects from the elements and their attributes specified within, and then adding the hierarchy of those views and viewgroups to the parent ViewGroup. When you call setContentView(), it attaches the views it creates from reading the XML to the activity. You can also use LayoutInflater to add views to another ViewGroup, which can be a useful tool in a lot of circumstances.

How do I loop through rows with a data reader in C#?

int count = reader.FieldCount;
while(reader.Read()) {
    for(int i = 0 ; i < count ; i++) {
        Console.WriteLine(reader.GetValue(i));
    }
}

Note; if you have multiple grids, then:

do {
    int count = reader.FieldCount;
    while(reader.Read()) {
        for(int i = 0 ; i < count ; i++) {
            Console.WriteLine(reader.GetValue(i));
        }
    }
} while (reader.NextResult())

Limit Decimal Places in Android EditText

Create a new class in Android kotlin with the name DecimalDigitsInputFilter

class DecimalDigitsInputFilter(digitsBeforeDecimal: Int, digitsAfterDecimal: Int) : InputFilter {

    var mPattern: Pattern = Pattern.compile("[0-9]{0,$digitsBeforeDecimal}+((\\.[0-9]{0,$digitsAfterDecimal})?)||(\\.)?")

    override fun filter(
        source: CharSequence?,
        start: Int,
        end: Int,
        dest: Spanned?,
        dstart: Int,
        dend: Int
    ): CharSequence? {
        val matcher: Matcher = mPattern.matcher(
            dest?.subSequence(0, dstart).toString() + source?.subSequence(
                start,
                end
            ).toString() + dest?.subSequence(dend, dest.length).toString()
        )
        if (!matcher.matches())
            return ""
        else
            return null
    }
}

Call this class with the following line

 et_buy_amount.filters = (arrayOf<InputFilter>(DecimalDigitsInputFilter(8,2)))

there are too many answers for the same but it will allow you to enter 8 digit before decimal and 2 digits after decimal

other answers are accepting only 8 digits

async await return Task

In order to get proper responses back from async methods, you need to put await while calling those task methods. That will wait for converting it back to the returned value type rather task type.

E.g var content = await StringAsyncTask (

where public async Task<String> StringAsyncTask ())

Login failed for user 'NT AUTHORITY\NETWORK SERVICE'

The SQL Server login required is DOMAIN\machinename$. This is the how the calling NT AUTHORITY\NETWORK SERVICE appears to SQL Server (and file servers etc)

In SQL,

CREATE LOGIN [XYZ\Gandalf$] FROM WINDOWS

I am getting an "Invalid Host header" message when connecting to webpack-dev-server remotely

I found out, that I need to set the public property of devServer, to my request's host value. Being that it will be displayed at that external address.

So I needed this in my webpack.config.js

devServer: {
  compress: true,
  public: 'store-client-nestroia1.c9users.io' // That solved it
}

Another solution is using it on the CLI:

webpack-dev-server --public $C9_HOSTNAME <-- var for Cloud9 external IP

Twitter Bootstrap 3, vertically center content

You can use display:inline-block instead of float and vertical-align:middle with this CSS:

.col-lg-4, .col-lg-8 {
    float:none;
    display:inline-block;
    vertical-align:middle;
    margin-right:-4px;
}

The demo http://bootply.com/94402

MongoDB SELECT COUNT GROUP BY

Mongo shell command that worked for me:

db.getCollection(<collection_name>).aggregate([{"$match": {'<key>': '<value to match>'}}, {"$group": {'_id': {'<group_by_attribute>': "$group_by_attribute"}}}])

Can iterators be reset in Python?

Problem

I've had the same issue before. After analyzing my code, I realized that attempting to reset the iterator inside of loops slightly increases the time complexity and it also makes the code a bit ugly.

Solution

Open the file and save the rows to a variable in memory.

# initialize list of rows
rows = []

# open the file and temporarily name it as 'my_file'
with open('myfile.csv', 'rb') as my_file:

    # set up the reader using the opened file
    myfilereader = csv.DictReader(my_file)

    # loop through each row of the reader
    for row in myfilereader:
        # add the row to the list of rows
        rows.append(row)

Now you can loop through rows anywhere in your scope without dealing with an iterator.

CSS-Only Scrollable Table with fixed headers

This answer will be used as a placeholder for the not fully supported position: sticky and will be updated over time. It is currently advised to not use the native implementation of this in a production environment.

See this for the current support: https://caniuse.com/#feat=css-sticky


Use of position: sticky

An alternative answer would be using position: sticky. As described by W3C:

A stickily positioned box is positioned similarly to a relatively positioned box, but the offset is computed with reference to the nearest ancestor with a scrolling box, or the viewport if no ancestor has a scrolling box.

This described exactly the behavior of a relative static header. It would be easy to assign this to the <thead> or the first <tr> HTML-tag, as this should be supported according to W3C. However, both Chrome, IE and Edge have problems assigning a sticky position property to these tags. There also seems to be no priority in solving this at the moment.

What does seem to work for a table element is assigning the sticky property to a table-cell. In this case the <th> cells.

Because a table is not a block-element that respects the static size you assign to it, it is best to use a wrapper element to define the scroll-overflow.

The code

_x000D_
_x000D_
div {_x000D_
  display: inline-block;_x000D_
  height: 150px;_x000D_
  overflow: auto_x000D_
}_x000D_
_x000D_
table th {_x000D_
  position: -webkit-sticky;_x000D_
  position: sticky;_x000D_
  top: 0;_x000D_
}_x000D_
_x000D_
_x000D_
/* == Just general styling, not relevant :) == */_x000D_
_x000D_
table {_x000D_
  border-collapse: collapse;_x000D_
}_x000D_
_x000D_
th {_x000D_
  background-color: #1976D2;_x000D_
  color: #fff;_x000D_
}_x000D_
_x000D_
th,_x000D_
td {_x000D_
  padding: 1em .5em;_x000D_
}_x000D_
_x000D_
table tr {_x000D_
  color: #212121;_x000D_
}_x000D_
_x000D_
table tr:nth-child(odd) {_x000D_
  background-color: #BBDEFB;_x000D_
}
_x000D_
<div>_x000D_
  <table border="0">_x000D_
    <thead>_x000D_
      <tr>_x000D_
        <th>head1</th>_x000D_
        <th>head2</th>_x000D_
        <th>head3</th>_x000D_
        <th>head4</th>_x000D_
      </tr>_x000D_
    </thead>_x000D_
    <tr>_x000D_
      <td>row 1, cell 1</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>row 2, cell 1</td>_x000D_
      <td>row 2, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>row 2, cell 1</td>_x000D_
      <td>row 2, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>row 2, cell 1</td>_x000D_
      <td>row 2, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>row 2, cell 1</td>_x000D_
      <td>row 2, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
      <td>row 1, cell 2</td>_x000D_
    </tr>_x000D_
  </table>_x000D_
</div>
_x000D_
_x000D_
_x000D_

In this example I use a simple <div> wrapper to define the scroll-overflow done with a static height of 150px. This can of course be any size. Now that the scrolling box has been defined, the sticky <th> elements will corespondent "to the nearest ancestor with a scrolling box", which is the div-wrapper.


Use of a position: sticky polyfill

Non-supported devices can make use of a polyfill, which implements the behavior through code. An example is stickybits, which resembles the same behavior as the browser's implemented position: sticky.

Example with polyfill: http://jsfiddle.net/7UZA4/6957/

exporting multiple modules in react.js

When you

import App from './App.jsx';

That means it will import whatever you export default. You can rename App class inside App.jsx to whatever you want as long as you export default it will work but you can only have one export default.

So you only need to export default App and you don't need to export the rest.

If you still want to export the rest of the components, you will need named export.

https://developer.mozilla.org/en/docs/web/javascript/reference/statements/export

Type of expression is ambiguous without more context Swift

This can happen if any part of your highlighted method or property is attempting to access a property or method with the incorrect type.

Here is a troubleshooting checklist:

  • Make sure the type of arguments match in the call site and implementation.
  • Make sure the argument names match in the call site and implementation.
  • Make sure the method name matches in the call site and implementation.
  • Make sure the returned value of a property or method matches in the usage and implementation (ie: enumerated())
  • Make sure you don't have a duplicated method with potentially ambiguous types such as with protocols or generics.
  • Make sure the compiler can infer the correct type when using type inference.

A Strategy

  • Try breaking apart your method into a greater number of simpler method/implementations.

For example, lets say you are running compactMap on an array of custom Types. In the closure you are passing to the compactMap method, you initialize and return another custom struct. When you get this error, it is difficult to tell which part of your code is offending.

  • For debugging purposes, you can use a for loop instead of compactMap.
  • instead of passing the arguments, directly, you can assign them to constants in the for loop.

By this point, you may come to a realization, such as, instead of the property you thought you wanted to assign actually had a property on it that had the actual value you wanted to pass.

How to match letters only using java regex, matches method?

"[a-zA-Z]" matches only one character. To match multiple characters, use "[a-zA-Z]+".

Since a dot is a joker for any character, you have to mask it: "abc\." To make the dot optional, you need a question mark: "abc\.?"

If you write the Pattern as literal constant in your code, you have to mask the backslash:

System.out.println ("abc".matches ("abc\\.?"));
System.out.println ("abc.".matches ("abc\\.?"));
System.out.println ("abc..".matches ("abc\\.?"));

Combining both patterns:

System.out.println ("abc.".matches ("[a-zA-Z]+\\.?"));

Instead of a-zA-Z, \w is often more appropriate, since it captures foreign characters like äöüßø and so on:

System.out.println ("abc.".matches ("\\w+\\.?"));   

How do I programmatically set device orientation in iOS 7?

The only way that worked for me is presenting dummy modal view controller.

UIViewController* dummyVC = [[UIViewController alloc] init];
dummyVC.view = [[UIView alloc] init];
[self presentModalViewController:dummyVC animated:NO];
[self dismissModalViewControllerAnimated:NO];

Your VC will be asked for updated interface orientations when modal view controller is dismissed.

Curious thing is that UINavigationController does exactly this when pushing/popping child view controllers with different supported interface orientations (tested on iOS 6.1, 7.0).

Virtualenv Command Not Found

In my case, I ran pip show virtualenv to get the information about virtualenv package. I will look similar to this and will also show location of the package:

user@machine:~$ pip show virtualenv
Name: virtualenv
Version: 16.2.0
Summary: Virtual Python Environment builder
Home-page: https://virtualenv.pypa.io/
Author: Ian Bicking
Author-email: [email protected]
License: MIT
Location: /home/user/.local/lib/python3.6/site-packages
Requires: setuptools

From that grab the part of location up to the .local part, which in this case is /home/user/.local/. You can find virtualenv command under /home/user/.local/bin/virtualenv.

You can then run commands like /home/user/.local/bin/virtualenv newvirtualenv.

Convert char to int in C#

Principle:

char foo = '2';
int bar = foo & 15;

The binary of the ASCII charecters 0-9 is:

0   -   0011 0000
1   -   0011 0001
2   -   0011 0010
3   -   0011 0011
4   -   0011 0100
5   -   0011 0101
6   -   0011 0110
7   -   0011 0111
8   -   0011 1000
9   -   0011 1001

and if you take in each one of them the first 4 LSB (using bitwise AND with 8'b00001111 that equals to 15) you get the actual number (0000 = 0,0001=1,0010=2,... )

Usage:

public static int CharToInt(char c)
{
    return 0b0000_1111 & (byte) c;
}

Why does datetime.datetime.utcnow() not contain timezone information?

To add timezone information in Python 3.2+

import datetime

>>> d = datetime.datetime.now(tz=datetime.timezone.utc)
>>> print(d.tzinfo)
'UTC+00:00'

Calculate date from week number

UPDATE: .NET Core 3.0 and .NET Standard 2.1 has shipped with this type.

Good news! A pull request adding System.Globalization.ISOWeek to .NET Core was just merged and is currently slated for the 3.0 release. Hopefully it will propagate to the other .NET platforms in a not-too-distant future.

You should be able to use the ISOWeek.ToDateTime(int year, int week, DayOfWeek dayOfWeek) method to calculate this.

You can find the source code here.

How to specify multiple return types using type-hints

The statement def foo(client_id: str) -> list or bool: when evaluated is equivalent to def foo(client_id: str) -> list: and will therefore not do what you want.

The native way to describe a "either A or B" type hint is Union (thanks to Bhargav Rao):

def foo(client_id: str) -> Union[list, bool]:

I do not want to be the "Why do you want to do this anyway" guy, but maybe having 2 return types isn't what you want:

If you want to return a bool to indicate some type of special error-case, consider using Exceptions instead. If you want to return a bool as some special value, maybe an empty list would be a good representation. You can also indicate that None could be returned with Optional[list]

Rerender view on browser resize with React

componentDidMount() {

    // Handle resize
    window.addEventListener('resize', this.handleResize);
}




handleResize = () => {
    this.renderer.setSize(this.mount.clientWidth, this.mount.clientHeight);
    this.camera.aspect = this.mount.clientWidth / this.mount.clientHeight;
    this.camera.updateProjectionMatrix();
};

Only need to define resize event function.

Then update the renderers size ( canvas ), assign a new aspect ratio for the camera.

Unmounting and remouting is a crazy solution in my opinion....

below is the mount if needed.

            <div
                className={this.state.canvasActive ? 'canvasContainer isActive' : 'canvasContainer'}
                ref={mount => {
                    this.mount = mount;
                }}
            />

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

Using Crypto++, you could do the following:

#include <sha.h>
#include <iostream> 

SHA256 sha; 
while ( !f.eof() ) { 
   char buff[4096];
   int numchars = f.read(...); 
   sha.Update(buff, numchars); 
}
char hash[size]; 
sha.Final(hash); 
cout << hash <<endl; 

I have a need for something very similar, because I can't read in multi-gigabyte files just to compute a hash. In theory I could memory map them, but I have to support 32bit platforms - that's still problematic for large files.

EntityType has no key defined error

Using the [key] didn't work for me but using an id property does it. I just add this property in my class.

public int id {get; set;}

Easiest way to parse a comma delimited string to some kind of object I can loop through to access the individual values?

   var stringToSplit = "0, 10, 20, 30, 100, 200";

    // To parse your string 
    var elements = test.Split(new[]
    { ',' }, System.StringSplitOptions.RemoveEmptyEntries);

    // To Loop through
    foreach (string items in elements)
    {
       // enjoy
    }

How do I create sql query for searching partial matches?

First of all, this approach won't scale in the large, you'll need a separate index from words to item (like an inverted index).

If your data is not large, you can do

SELECT DISTINCT(name) FROM mytable WHERE name LIKE '%mall%' OR description LIKE '%mall%'

using OR if you have multiple keywords.

Check if a given time lies between two times regardless of date

strip colons from the $time, $to and $from strings, convert to int and then use the following condition to check if the time is between from and to. Example is in php, but shouldn't matter.

if(($to < $from && ($time >= $from || $time <= $to)) ||
    ($time >= $from && $time <= $to)) {
    return true;
}

How do you import an Eclipse project into Android Studio now?

According to http://tools.android.com/tech-docs/new-build-system/migrating-from-eclipse-projects, You have a couple of choices
- simply importing
- pre-exporting first from Eclipse.

Pre-exporting from eclipse may be the better choice if your project contains a lot of relationships that are Eclipse-specific. A.S. cannot 'translate' everything Eclipse can produce. If you want to continue using Eclipse as well as A.S. on this project code, this is the better choice. If you choose this method, please read the above link, there are some important pre-requisites.

Simply importing into AS will let AS 'translate' and rearrange the project, and is the recommended method, especially if you have no intention of returning to Eclipse. In this case, you let the A.S. wizard do everything and you dont need to manually generate gradle files.

document.getElementById('btnid').disabled is not working in firefox and chrome

stay true to native (Boolean) property support and its powerful syntax like:

[elem].disabled = condition ? true : false; //done!

and for our own good collective coding experience, -please insist on others to support it as well.

Running Groovy script from the command line

It will work on Linux kernel 2.6.28 (confirmed on 4.9.x). It won't work on FreeBSD and other Unix flavors.

Your /usr/local/bin/groovy is a shell script wrapping the Java runtime running Groovy.

See the Interpreter Scripts section of EXECVE(2) and EXECVE(2).

Image encryption/decryption using AES256 symmetric block ciphers

Try with the below code it`s working for me.

public static String decrypt(String encrypted) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException {
    byte[] key = your Key in byte array;
    byte[] input = salt in byte array;

    SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
    IvParameterSpec ivSpec = new IvParameterSpec(input);
    Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    ecipher.init(Cipher.DECRYPT_MODE, skeySpec, ivSpec);

    byte[] raw = Base64.decode(encrypted, Base64.DEFAULT);
    byte[] originalBytes = ecipher.doFinal(raw);

    String original = new String(originalBytes, "UTF8");
    return original;
}

Execute script after specific delay using JavaScript

I had some ajax commands I wanted to run with a delay in between. Here is a simple example of one way to do that. I am prepared to be ripped to shreds though for my unconventional approach. :)

//  Show current seconds and milliseconds
//  (I know there are other ways, I was aiming for minimal code
//  and fixed width.)
function secs()
{
    var s = Date.now() + ""; s = s.substr(s.length - 5);
  return s.substr(0, 2) + "." + s.substr(2);
}

//  Log we're loading
console.log("Loading: " + secs());

//  Create a list of commands to execute
var cmds = 
[
    function() { console.log("A: " + secs()); },
    function() { console.log("B: " + secs()); },
    function() { console.log("C: " + secs()); },
    function() { console.log("D: " + secs()); },
    function() { console.log("E: " + secs()); },
  function() { console.log("done: " + secs()); }
];

//  Run each command with a second delay in between
var ms = 1000;
cmds.forEach(function(cmd, i)
{
    setTimeout(cmd, ms * i);
});

// Log we've loaded (probably logged before first command)
console.log("Loaded: " + secs());

You can copy the code block and paste it into a console window and see something like:

Loading: 03.077
Loaded: 03.078
A: 03.079
B: 04.075
C: 05.075
D: 06.075
E: 07.076
done: 08.076

VB.Net Properties - Public Get, Private Set

I'm not sure what the minimum required version of Visual Studio is, but in VS2015 you can use

Public ReadOnly Property Name As String

It is read-only for public access but can be privately modified using _Name

Case-insensitive string comparison in C++

Doing this without using Boost can be done by getting the C string pointer with c_str() and using strcasecmp:

std::string str1 ="aBcD";
std::string str2 = "AbCd";;
if (strcasecmp(str1.c_str(), str2.c_str()) == 0)
{
    //case insensitive equal 
}

What's the best way to get the last element of an array without deleting it?

One way to avoid pass-by-reference errors (eg. "end(array_values($foo))") is to use call_user_func or call_user_func_array:

// PHP Fatal error: Only variables can be passed by reference
// No output (500 server error)
var_dump(end(array(1, 2, 3)));

// No errors, but modifies the array's internal pointer
// Outputs "int(3)"
var_dump(call_user_func('end', array(1, 2, 3)));

// PHP Strict standards:  Only variables should be passed by reference
// Outputs "int(3)"
var_dump(end(array_values(array(1, 2, 3))));

// No errors, doesn't change the array
// Outputs "int(3)"
var_dump(call_user_func('end', array_values(array(1, 2, 3))));

How to print last two columns using awk

awk '{print $NF-1, $NF}'  inputfile

Note: this works only if at least two columns exist. On records with one column you will get a spurious "-1 column1"

When to use MongoDB or other document oriented database systems?

In NoSQL: If Only It Was That Easy, the author writes about MongoDB:

MongoDB is not a key/value store, it’s quite a bit more. It’s definitely not a RDBMS either. I haven’t used MongoDB in production, but I have used it a little building a test app and it is a very cool piece of kit. It seems to be very performant and either has, or will have soon, fault tolerance and auto-sharding (aka it will scale). I think Mongo might be the closest thing to a RDBMS replacement that I’ve seen so far. It won’t work for all data sets and access patterns, but it’s built for your typical CRUD stuff. Storing what is essentially a huge hash, and being able to select on any of those keys, is what most people use a relational database for. If your DB is 3NF and you don’t do any joins (you’re just selecting a bunch of tables and putting all the objects together, AKA what most people do in a web app), MongoDB would probably kick ass for you.

Then, in the conclusion:

The real thing to point out is that if you are being held back from making something super awesome because you can’t choose a database, you are doing it wrong. If you know mysql, just use it. Optimize when you actually need to. Use it like a k/v store, use it like a rdbms, but for god sake, build your killer app! None of this will matter to most apps. Facebook still uses MySQL, a lot. Wikipedia uses MySQL, a lot. FriendFeed uses MySQL, a lot. NoSQL is a great tool, but it’s certainly not going to be your competitive edge, it’s not going to make your app hot, and most of all, your users won’t care about any of this.

What am I going to build my next app on? Probably Postgres. Will I use NoSQL? Maybe. I might also use Hadoop and Hive. I might keep everything in flat files. Maybe I’ll start hacking on Maglev. I’ll use whatever is best for the job. If I need reporting, I won’t be using any NoSQL. If I need caching, I’ll probably use Tokyo Tyrant. If I need ACIDity, I won’t use NoSQL. If I need a ton of counters, I’ll use Redis. If I need transactions, I’ll use Postgres. If I have a ton of a single type of documents, I’ll probably use Mongo. If I need to write 1 billion objects a day, I’d probably use Voldemort. If I need full text search, I’d probably use Solr. If I need full text search of volatile data, I’d probably use Sphinx.

I like this article, I find it very informative, it gives a good overview of the NoSQL landscape and hype. But, and that's the most important part, it really helps to ask yourself the right questions when it comes to choose between RDBMS and NoSQL. Worth the read IMHO.

Alternate link to article

Clear the value of bootstrap-datepicker

I came across this thread while trying to clear the date already set. Attempting:

$('#datepicker').val('').datepicker('update');

produced:

TypeError: t.dpDiv is undefined 
https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js -- Line 8

Thinking that perhaps one needed to include the original Datepicker for bootstrap removes the error, but then causes the original Datepicker widget to appear! - so that's obviously wrong and not needed.

Looking further, the crash in jqueryui is in:

    /* Generate the date picker content. */
_updateDatepicker: function(inst) {
    this.maxRows = 4; //Reset the max number of rows being displayed (see #7043)
    datepicker_instActive = inst; // for delegate hover events
    inst.dpDiv.empty().append(this._generateHTML(inst));
    this._attachHandlers(inst);

and inst.pdDiv does not exist.

Investigating further - I realized that what was needed was:

        $formControl = $duedate.find("input");
        $formControl.val('');
        $formControl.removeData();

Which solved my problem. Note I also needed the $formControl.removeData() otherwise the state of the widget would not be reinitialized to the initial state.

I hope this helps someone else. :-)

Cannot use object of type stdClass as array?

It's not an array, it's an object of type stdClass.

You can access it like this:

echo $oResult->context;

More info here: What is stdClass in PHP?

Read user input inside a loop

echo "Enter the Programs you want to run:"
> ${PROGRAM_LIST}
while read PROGRAM_ENTRY
do
   if [ ! -s ${PROGRAM_ENTRY} ]
   then
      echo ${PROGRAM_ENTRY} >> ${PROGRAM_LIST}
   else
      break
   fi
done

How to parse JSON boolean value?

Try this:

{
    "ACCOUNT_EXIST": true,
    "MultipleContacts": false
}

boolean success ((Boolean) jsonObject.get("ACCOUNT_EXIST")).booleanValue()

Error in contrasts when defining a linear model in R

The answers by the other authors have already addressed the problem of factors with only one level or NAs.

Today, I stumbled upon the same error when using the rstatix::anova_test() function but my factors were okay (more than one level, no NAs, no character vectors, ...). Instead, I could fix the error by dropping all variables in the dataframe that are not included in the model. I don't know what's the reason for this behavior but just knowing about this might also be helpful when encountering this error.

Converting HTML files to PDF

You can use a headless firefox with an extension. It's pretty annoying to get running but it does produce good results.

Check out this answer for more info.

Enum String Name from Value

For getting the String value [Name]:

EnumDisplayStatus enumDisplayStatus = (EnumDisplayStatus)GetDBValue();
string stringValue = $"{enumDisplayStatus:G}"; 

And for getting the enum value:

string stringValue = $"{enumDisplayStatus:D}";
SetDBValue(Convert.ToInt32(stringValue ));

How do I put a clear button inside my HTML text input box like the iPhone does?

@Mahmoud Ali Kaseem

I have just changed some CSS to make it look different and added focus();

https://jsfiddle.net/xn9eogmx/81/

_x000D_
_x000D_
$('#clear').click(function() {_x000D_
  $('#input-outer input').val('');_x000D_
  $('#input-outer input').focus();_x000D_
});
_x000D_
body {_x000D_
  font-family: "Arial";_x000D_
  font-size: 14px;_x000D_
}_x000D_
#input-outer {_x000D_
  height: 2em;_x000D_
  width: 15em;_x000D_
  border: 1px #777 solid;_x000D_
  position: relative;_x000D_
  padding: 0px;_x000D_
  border-radius: 4px;_x000D_
}_x000D_
#input-outer input {_x000D_
  height: 100%;_x000D_
  width: 100%;_x000D_
  border: 0px;_x000D_
  outline: none;_x000D_
  margin: 0 0 0 0px;_x000D_
  color: #666;_x000D_
  box-sizing: border-box;_x000D_
  padding: 5px;_x000D_
  padding-right: 35px;_x000D_
  border-radius: 4px;_x000D_
}_x000D_
#clear {_x000D_
  position: absolute;_x000D_
  float: right;_x000D_
  height: 2em;_x000D_
  width: 2em;_x000D_
  top: 0px;_x000D_
  right: 0px;_x000D_
  background: #aaa;_x000D_
  color: white;_x000D_
  text-align: center;_x000D_
  cursor: pointer;_x000D_
  border-radius: 0px 4px 4px 0px;_x000D_
}_x000D_
#clear:after {_x000D_
  content: "\274c";_x000D_
  position: absolute;_x000D_
  top: 4px;_x000D_
  right: 7px;_x000D_
}_x000D_
#clear:hover,_x000D_
#clear:focus {_x000D_
  background: #888;_x000D_
}_x000D_
#clear:active {_x000D_
  background: #666;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<div id="input-outer">_x000D_
  <input type="text">_x000D_
  <div id="clear"></div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Find the server name for an Oracle database

SELECT  host_name
FROM    v$instance

Difference between binary tree and binary search tree

  • Binary search tree: when inorder traversal is made on binary tree, you get sorted values of inserted items
  • Binary tree: no sorted order is found in any kind of traversal

Setting Java heap space under Maven 2 on Windows

It should be the same command, except SET instead of EXPORT

  • set MAVEN_OPTS=-Xmx512m would give it 512Mb of heap
  • set MAVEN_OPTS=-Xmx2048m would give it 2Gb of heap

Eclipse C++ : "Program "g++" not found in PATH"

The reason is that eclipse cannot find your gcc or g++ environment variable path.

You might have tried to run c or c++ or fortran but eclipse cannot find out the compiler.

So, add the path in your environment variable.

  1. Windows -> Search -environment variables -> click on environmental variables at bottom.

  2. Click on path ->edit -> new -> your variable path

Path should be entire, for example:

C:\Users\mahidhai\cygwin64\usr\sbin

Make sure that the variable is permanently stored. It is not erased after you close the environment variables GUI.

Sometimes you might find it difficult to add a path variable. Make sure windows is updated.

Even if Windows is updated and you have problems, directly go to the registry and navigate to the below.

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

Add your path here. Remove any unnecessary repetitions of path variables.

Note: You need to add your path variables in system environment variables -path

jQuery - How to dynamically add a validation rule

You need to call .validate() before you can add rules this way, like this:

$("#myForm").validate(); //sets up the validator
$("input[id*=Hours]").rules("add", "required");

The .validate() documentation is a good guide, here's the blurb about .rules("add", option):

Adds the specified rules and returns all rules for the first matched element. Requires that the parent form is validated, that is, $("form").validate() is called first.

Cannot resolve symbol 'AppCompatActivity'

When you add AndroidX support in Gradle.properties file e.g.

android.useAndroidX=true
android.enableJetifier=true

If you are using Gradle version greater than 3.2, the conventional Appcompat dependancy e.g.

implementation 'com.android.support:appcompat-v7:27.1.1

wont work. Replace this dependancy with:

implementation 'androidx.appcompat:appcompat:1.1.0'

Moreover, change the AppCompatActivity import in your class file from this:

import android.support.v7.app.AppCompatActivity;

to this:

import androidx.appcompat.app.AppCompatActivity;

Done

Can you style html form buttons with css?

You can achieve your desired through easily by CSS :-

HTML

<input type="submit" name="submit" value="Submit Application" id="submit" />

CSS

#submit {
    background-color: #ccc;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    border-radius:6px;
    color: #fff;
    font-family: 'Oswald';
    font-size: 20px;
    text-decoration: none;
    cursor: pointer;
    border:none;
}



#submit:hover {
    border: none;
    background:red;
    box-shadow: 0px 0px 1px #777;
}

DEMO

PostgreSQL JOIN data from 3 tables

Maybe the following is what you are looking for:

SELECT name, pathfilename
  FROM table1
  NATURAL JOIN table2
  NATURAL JOIN table3
  WHERE name = 'John';

Format timedelta to string

You can just convert the timedelta to a string with str(). Here's an example:

import datetime
start = datetime.datetime(2009,2,10,14,00)
end   = datetime.datetime(2009,2,10,16,00)
delta = end-start
print(str(delta))
# prints 2:00:00

How to change the color of text in javafx TextField?

Setting the -fx-text-fill works for me.

See below:

if (passed) {
    resultInfo.setText("Passed!");
    resultInfo.setStyle("-fx-text-fill: green; -fx-font-size: 16px;");
} else {
    resultInfo.setText("Failed!");
    resultInfo.setStyle("-fx-text-fill: red; -fx-font-size: 16px;");
}

Using python's eval() vs. ast.literal_eval()?

eval: This is very powerful, but is also very dangerous if you accept strings to evaluate from untrusted input. Suppose the string being evaluated is "os.system('rm -rf /')" ? It will really start deleting all the files on your computer.

ast.literal_eval: Safely evaluate an expression node or a string containing a Python literal or container display. The string or node provided may only consist of the following Python literal structures: strings, bytes, numbers, tuples, lists, dicts, sets, booleans, None, bytes and sets.

Syntax:

eval(expression, globals=None, locals=None)
import ast
ast.literal_eval(node_or_string)

Example:

# python 2.x - doesn't accept operators in string format
import ast
ast.literal_eval('[1, 2, 3]')  # output: [1, 2, 3]
ast.literal_eval('1+1') # output: ValueError: malformed string


# python 3.0 -3.6
import ast
ast.literal_eval("1+1") # output : 2
ast.literal_eval("{'a': 2, 'b': 3, 3:'xyz'}") # output : {'a': 2, 'b': 3, 3:'xyz'}
# type dictionary
ast.literal_eval("",{}) # output : Syntax Error required only one parameter
ast.literal_eval("__import__('os').system('rm -rf /')") # output : error

eval("__import__('os').system('rm -rf /')") 
# output : start deleting all the files on your computer.
# restricting using global and local variables
eval("__import__('os').system('rm -rf /')",{'__builtins__':{}},{})
# output : Error due to blocked imports by passing  '__builtins__':{} in global

# But still eval is not safe. we can access and break the code as given below
s = """
(lambda fc=(
lambda n: [
    c for c in 
        ().__class__.__bases__[0].__subclasses__() 
        if c.__name__ == n
    ][0]
):
fc("function")(
    fc("code")(
        0,0,0,0,"KABOOM",(),(),(),"","",0,""
    ),{}
)()
)()
"""
eval(s, {'__builtins__':{}})

In the above code ().__class__.__bases__[0] nothing but object itself. Now we instantiated all the subclasses, here our main enter code hereobjective is to find one class named n from it.

We need to code object and function object from instantiated subclasses. This is an alternative way from CPython to access subclasses of object and attach the system.

From python 3.7 ast.literal_eval() is now stricter. Addition and subtraction of arbitrary numbers are no longer allowed. link

How to change fonts in matplotlib (python)?

Say you want Comic Sans for the title and Helvetica for the x label.

csfont = {'fontname':'Comic Sans MS'}
hfont = {'fontname':'Helvetica'}

plt.title('title',**csfont)
plt.xlabel('xlabel', **hfont)
plt.show()

Several ports (8005, 8080, 8009) required by Tomcat Server at localhost are already in use

I checked all the answers but informing only to kill PID.

In case if you have terminal access shared by all it will not help or maybe you do not have permission to kill PID.

In this case what you can do is:

Double click on server

Go to Overview and change ports in Ports like this:

enter image description here

How to write a function that takes a positive integer N and returns a list of the first N natural numbers

Here are a few ways to create a list with N of continuous natural numbers starting from 1.

1 range:

def numbers(n): 
    return range(1, n+1);

2 List Comprehensions:

def numbers(n):
    return [i for i in range(1, n+1)]

You may want to look into the method xrange and the concepts of generators, those are fun in python. Good luck with your Learning!

How to pass multiple parameters in json format to a web service using jquery?

I think the best way is:

data: "{'Ids':['2','2']}"

To read this values Ids[0], Ids[1].

How to change a Git remote on Heroku

This worked for me:

git remote set-url heroku <repo git>

This replacement old url heroku.

You can check with:

git remote -v

Viewing full version tree in git

There is a very good answer to the same question.
Adding following lines to "~/.gitconfig":

[alias]
lg1 = log --graph --abbrev-commit --decorate --date=relative --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all
lg2 = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset) %C(dim white)- %an%C(reset)' --all
lg = !"git lg1"

How to Specify Eclipse Proxy Authentication Credentials?

If you have still problems, try deactivating ("Clear") SOCKS

see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=281384 "I believe the reason for this is because it uses the SOCKS proxy instead of the HTTP proxy if SOCKS is configured."

What is the full path to the Packages folder for Sublime text 2 on Mac OS Lion

A useful shortcut from inside Sublime Text:

cmd-shift-P --> Browse Packages Now open user folder.

Circle-Rectangle collision detection (intersection)

Here's my C code for resolving a collision between a sphere and a non-axis aligned box. It relies on a couple of my own library routines, but it may prove useful to some. I'm using it in a game and it works perfectly.

float physicsProcessCollisionBetweenSelfAndActorRect(SPhysics *self, SPhysics *actor)
{
    float diff = 99999;

    SVector relative_position_of_circle = getDifference2DBetweenVectors(&self->worldPosition, &actor->worldPosition);
    rotateVector2DBy(&relative_position_of_circle, -actor->axis.angleZ); // This aligns the coord system so the rect becomes an AABB

    float x_clamped_within_rectangle = relative_position_of_circle.x;
    float y_clamped_within_rectangle = relative_position_of_circle.y;
    LIMIT(x_clamped_within_rectangle, actor->physicsRect.l, actor->physicsRect.r);
    LIMIT(y_clamped_within_rectangle, actor->physicsRect.b, actor->physicsRect.t);

    // Calculate the distance between the circle's center and this closest point
    float distance_to_nearest_edge_x = relative_position_of_circle.x - x_clamped_within_rectangle;
    float distance_to_nearest_edge_y = relative_position_of_circle.y - y_clamped_within_rectangle;

    // If the distance is less than the circle's radius, an intersection occurs
    float distance_sq_x = SQUARE(distance_to_nearest_edge_x);
    float distance_sq_y = SQUARE(distance_to_nearest_edge_y);
    float radius_sq = SQUARE(self->physicsRadius);
    if(distance_sq_x + distance_sq_y < radius_sq)   
    {
        float half_rect_w = (actor->physicsRect.r - actor->physicsRect.l) * 0.5f;
        float half_rect_h = (actor->physicsRect.t - actor->physicsRect.b) * 0.5f;

        CREATE_VECTOR(push_vector);         

        // If we're at one of the corners of this object, treat this as a circular/circular collision
        if(fabs(relative_position_of_circle.x) > half_rect_w && fabs(relative_position_of_circle.y) > half_rect_h)
        {
            SVector edges;
            if(relative_position_of_circle.x > 0) edges.x = half_rect_w; else edges.x = -half_rect_w;
            if(relative_position_of_circle.y > 0) edges.y = half_rect_h; else edges.y = -half_rect_h;   

            push_vector = relative_position_of_circle;
            moveVectorByInverseVector2D(&push_vector, &edges);

            // We now have the vector from the corner of the rect to the point.
            float delta_length = getVector2DMagnitude(&push_vector);
            float diff = self->physicsRadius - delta_length; // Find out how far away we are from our ideal distance

            // Normalise the vector
            push_vector.x /= delta_length;
            push_vector.y /= delta_length;
            scaleVector2DBy(&push_vector, diff); // Now multiply it by the difference
            push_vector.z = 0;
        }
        else // Nope - just bouncing against one of the edges
        {
            if(relative_position_of_circle.x > 0) // Ball is to the right
                push_vector.x = (half_rect_w + self->physicsRadius) - relative_position_of_circle.x;
            else
                push_vector.x = -((half_rect_w + self->physicsRadius) + relative_position_of_circle.x);

            if(relative_position_of_circle.y > 0) // Ball is above
                push_vector.y = (half_rect_h + self->physicsRadius) - relative_position_of_circle.y;
            else
                push_vector.y = -((half_rect_h + self->physicsRadius) + relative_position_of_circle.y);

            if(fabs(push_vector.x) < fabs(push_vector.y))
                push_vector.y = 0;
            else
                push_vector.x = 0;
        }

        diff = 0; // Cheat, since we don't do anything with the value anyway
        rotateVector2DBy(&push_vector, actor->axis.angleZ);
        SVector *from = &self->worldPosition;       
        moveVectorBy2D(from, push_vector.x, push_vector.y);
    }   
    return diff;
}

Unable to set default python version to python3 in ubuntu

To change Python 3.6.8 as the default in Ubuntu 18.04 to Python 3.7.

Install Python 3.7

Steps to install Python3.7 and configure it as the default interpreter.

  1. Install the python3.7 package using apt-get

    sudo apt-get install python3.7

  2. Add Python3.6 & Python 3.7 to update-alternatives

sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.6 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.7 2
  1. Update Python 3 to point to Python 3.7

    sudo update-alternatives --config python3 Enter 2 for Python 3.7

  2. Test the version of python

python3 --version
Python 3.7.1 

Free Online Team Foundation Server

You can use Visual Studio Team Services for free. Also you can import a TFS repo to this cloud space.

Calculating Page Table Size

Suppose logical address space is **32 bit so total possible logical entries will be 2^32 and other hand suppose each page size is 4 byte then size of one page is *2^2*2^10=2^12...* now we know that no. of pages in page table is pages=total possible logical address entries/page size so pages=2^32/2^12 =2^20 Now suppose that each entry in page table takes 4 bytes then total size of page table in *physical memory will be=2^2*2^20=2^22=4mb***

Test if numpy array contains only zeros

As another answer says, you can take advantage of truthy/falsy evaluations if you know that 0 is the only falsy element possibly in your array. All elements in an array are falsy iff there are not any truthy elements in it.*

>>> a = np.zeros(10)
>>> not np.any(a)
True

However, the answer claimed that any was faster than other options due partly to short-circuiting. As of 2018, Numpy's all and any do not short-circuit.

If you do this kind of thing often, it's very easy to make your own short-circuiting versions using numba:

import numba as nb

# short-circuiting replacement for np.any()
@nb.jit(nopython=True)
def sc_any(array):
    for x in array.flat:
        if x:
            return True
    return False

# short-circuiting replacement for np.all()
@nb.jit(nopython=True)
def sc_all(array):
    for x in array.flat:
        if not x:
            return False
    return True

These tend to be faster than Numpy's versions even when not short-circuiting. count_nonzero is the slowest.

Some input to check performance:

import numpy as np

n = 10**8
middle = n//2
all_0 = np.zeros(n, dtype=int)
all_1 = np.ones(n, dtype=int)
mid_0 = np.ones(n, dtype=int)
mid_1 = np.zeros(n, dtype=int)
np.put(mid_0, middle, 0)
np.put(mid_1, middle, 1)
# mid_0 = [1 1 1 ... 1 0 1 ... 1 1 1]
# mid_1 = [0 0 0 ... 0 1 0 ... 0 0 0]

Check:

## count_nonzero
%timeit np.count_nonzero(all_0) 
# 220 ms ± 8.73 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
%timeit np.count_nonzero(all_1)
# 150 ms ± 4.56 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

### all
# np.all
%timeit np.all(all_1)
%timeit np.all(mid_0)
%timeit np.all(all_0)
# 56.8 ms ± 3.41 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 57.4 ms ± 1.76 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 55.9 ms ± 2.13 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

# sc_all
%timeit sc_all(all_1)
%timeit sc_all(mid_0)
%timeit sc_all(all_0)
# 44.4 ms ± 2.49 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 22.7 ms ± 599 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 288 ns ± 6.36 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

### any
# np.any
%timeit np.any(all_0)
%timeit np.any(mid_1)
%timeit np.any(all_1)
# 60.7 ms ± 1.38 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 60 ms ± 287 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 57.7 ms ± 1.12 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

# sc_any
%timeit sc_any(all_0)
%timeit sc_any(mid_1)
%timeit sc_any(all_1)
# 41.7 ms ± 1.24 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 22.4 ms ± 1.51 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
# 287 ns ± 12.7 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

* Helpful all and any equivalences:

np.all(a) == np.logical_not(np.any(np.logical_not(a)))
np.any(a) == np.logical_not(np.all(np.logical_not(a)))
not np.all(a) == np.any(np.logical_not(a))
not np.any(a) == np.all(np.logical_not(a))

Printing pointers in C

It's not a pointer to character char* but a pointer to array of 4 characters: char* [4]. With g++ it doesn't compile:

main.cpp: In function ‘int main(int, char**)’: main.cpp:126: error: cannot convert ‘char (*)[4]’ to ‘char**’ in initialization

Moreover, the linux man pages says:

p

The void * pointer argument is printed in hexadecimal (as if by %#x or %#lx). It shoud be pointer to void.

You can change your code to:

char* s = "asd";
char** p = &s;

printf("The value of s is: %p\n", s);
printf("The address of s is: %p\n", &s);

printf("The value of p is: %p\n", p);
printf("The address of p is: %p\n", &p);

printf("The address of s[0] is: %p\n", &s[0]);
printf("The address of s[1] is: %p\n", &s[1]);
printf("The address of s[2] is: %p\n", &s[2]);

result:

The value of s is: 0x403f00

The address of s is: 0x7fff2df9d588

The value of p is: 0x7fff2df9d588

The address of p is: 0x7fff2df9d580

The address of s[0] is: 0x403f00

The address of s[1] is: 0x403f01

The address of s[2] is: 0x403f02

Exiting from python Command Line

If you stuck in python command line and none of above solutions worked for you, try exit(2)

Could not resolve com.android.support:appcompat-v7:26.1.0 in Android Studio new project

this work for me

compile 'com.android.support:appcompat-v7:26.0.0'

change 26.0.0 to 26.0.1

compile 'com.android.support:appcompat-v7:26.0.1'

What is Node.js' Connect, Express and "middleware"?

node.js

Node.js is a javascript motor for the server side.
In addition to all the js capabilities, it includes networking capabilities (like HTTP), and access to the file system.
This is different from client-side js where the networking tasks are monopolized by the browser, and access to the file system is forbidden for security reasons.

node.js as a web server: express

Something that runs in the server, understands HTTP and can access files sounds like a web server. But it isn't one.
To make node.js behave like a web server one has to program it: handle the incoming HTTP requests and provide the appropriate responses.
This is what Express does: it's the implementation of a web server in js.
Thus, implementing a web site is like configuring Express routes, and programming the site's specific features.

Middleware and Connect

Serving pages involves a number of tasks. Many of those tasks are well known and very common, so node's Connect module (one of the many modules available to run under node) implements those tasks.
See the current impressing offering:

  • logger request logger with custom format support
  • csrf Cross-site request forgery protection
  • compress Gzip compression middleware
  • basicAuth basic http authentication
  • bodyParser extensible request body parser
  • json application/json parser
  • urlencoded application/x-www-form-urlencoded parser
  • multipart multipart/form-data parser
  • timeout request timeouts
  • cookieParser cookie parser
  • session session management support with bundled MemoryStore
  • cookieSession cookie-based session support
  • methodOverride faux HTTP method support
  • responseTime calculates response-time and exposes via X-Response-Time
  • staticCache memory cache layer for the static() middleware
  • static streaming static file server supporting Range and more
  • directory directory listing middleware
  • vhost virtual host sub-domain mapping middleware
  • favicon efficient favicon server (with default icon)
  • limit limit the bytesize of request bodies
  • query automatic querystring parser, populating req.query
  • errorHandler flexible error handler

Connect is the framework and through it you can pick the (sub)modules you need.
The Contrib Middleware page enumerates a long list of additional middlewares.
Express itself comes with the most common Connect middlewares.

What to do?

Install node.js.
Node comes with npm, the node package manager.
The command npm install -g express will download and install express globally (check the express guide).
Running express foo in a command line (not in node) will create a ready-to-run application named foo. Change to its (newly created) directory and run it with node with the command node <appname>, then open http://localhost:3000 and see. Now you are in.

Jquery- Get the value of first td in table

Install firebug and use console.log instead of alert. Then you will see the exact element your accessing.

How to link to apps on the app store

Creating a link could become a complex issue when supporting multiple OS and multiple platform. For example the WebObjects isn't supported on iOS 7 (some of them), some links you create would open another country store then the user's etc.

There is an open source library called iLink that could help you.

There advantages of this library is that the links would be found and created at run time (the library would check the app ID and the OS it is running on and would figure out what link should be created). The best point in this is that you don't need to configure almost anything before using it so that is error free and would work always. That's great also if you have few targets on same project so you don't have to remember which app ID or link to use. This library also would prompt the user to upgrade the app if there is a new version on the store (this is built in and you turn this off by a simple flag) directly pointing to the upgrade page for the app if user agrees.

Copy the 2 library files to your project (iLink.h & iLink.m).

On your appDelegate.m:

#import "iLink.h"

+ (void)initialize
{
    //configure iLink
    [iLink sharedInstance].globalPromptForUpdate = YES; // If you want iLink to prompt user to update when the app is old.
}

and on the place you want to open the rating page for example just use:

[[iLink sharedInstance] iLinkOpenAppPageInAppStoreWithAppleID: YOUR_PAID_APP_APPLE_ID]; // You should find YOUR_PAID_APP_APPLE_ID from iTunes Connect 

Don't forget to import iLink.h on the same file.

There is a very good doc for the whole library there and an example projects for iPhone and for Mac.

Change location of log4j.properties

In Eclipse you can set a VM argument to:

-Dlog4j.configuration=file:///${workspace_loc:/MyProject/log4j-full-debug.properties}

Gradle finds wrong JAVA_HOME even though it's correctly set

In my Ubuntu, I have a headache for 2 days on this issue.

Step 1. Type on the terminal whereis java then it will display something like this

java: /usr/bin/java /etc/java /usr/share/java /usr/lib/jvm/java-8-openjdk-amd64/bin/java /usr/share/man/man1/java.1.gz

Step 2. Take note of the path: /usr/lib/jvm/java-8-openjdk-amd64/bin/java

exclude the bin/java

your JAVA_HOME = /usr/lib/jvm/java-8-openjdk-amd64

Can I disable a CSS :hover effect via JavaScript?

This is similar to aSeptik's answer, but what about this approach? Wrap the CSS code which you want to disable using JavaScript in <noscript> tags. That way if javaScript is off, the CSS :hover will be used, otherwise the JavaScript effect will be used.

Example:

<noscript>
<style type="text/css">
ul#mainFilter a:hover {
  /* some CSS attributes here */
}
</style>
</noscript>
<script type="text/javascript">
$("ul#mainFilter a").hover(
     function(o){ /* ...do your stuff... */ }, 
     function(o){ /* ...do your stuff... */ });
</script>

Get data from JSON file with PHP

Use json_decode to transform your JSON into a PHP array. Example:

$json = '{"a":"b"}';
$array = json_decode($json, true);
echo $array['a']; // b

How can I undo a `git commit` locally and on a remote after `git push`

git reset HEAD~1 if you don't want your changes to be gone(unstaged changes). Change, commit and push again git push -f [origin] [branch]

Take a screenshot via a Python script on Linux

Compile all answers in one class. Outputs PIL image.

#!/usr/bin/env python
# encoding: utf-8
"""
screengrab.py

Created by Alex Snet on 2011-10-10.
Copyright (c) 2011 CodeTeam. All rights reserved.
"""

import sys
import os

import Image


class screengrab:
    def __init__(self):
        try:
            import gtk
        except ImportError:
            pass
        else:
            self.screen = self.getScreenByGtk

        try:
            import PyQt4
        except ImportError:
            pass
        else:
            self.screen = self.getScreenByQt

        try:
            import wx
        except ImportError:
            pass
        else:
            self.screen = self.getScreenByWx

        try:
            import ImageGrab
        except ImportError:
            pass
        else:
            self.screen = self.getScreenByPIL


    def getScreenByGtk(self):
        import gtk.gdk      
        w = gtk.gdk.get_default_root_window()
        sz = w.get_size()
        pb = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB,False,8,sz[0],sz[1])
        pb = pb.get_from_drawable(w,w.get_colormap(),0,0,0,0,sz[0],sz[1])
        if pb is None:
            return False
        else:
            width,height = pb.get_width(),pb.get_height()
            return Image.fromstring("RGB",(width,height),pb.get_pixels() )

    def getScreenByQt(self):
        from PyQt4.QtGui import QPixmap, QApplication
        from PyQt4.Qt import QBuffer, QIODevice
        import StringIO
        app = QApplication(sys.argv)
        buffer = QBuffer()
        buffer.open(QIODevice.ReadWrite)
        QPixmap.grabWindow(QApplication.desktop().winId()).save(buffer, 'png')
        strio = StringIO.StringIO()
        strio.write(buffer.data())
        buffer.close()
        del app
        strio.seek(0)
        return Image.open(strio)

    def getScreenByPIL(self):
        import ImageGrab
        img = ImageGrab.grab()
        return img

    def getScreenByWx(self):
        import wx
        wx.App()  # Need to create an App instance before doing anything
        screen = wx.ScreenDC()
        size = screen.GetSize()
        bmp = wx.EmptyBitmap(size[0], size[1])
        mem = wx.MemoryDC(bmp)
        mem.Blit(0, 0, size[0], size[1], screen, 0, 0)
        del mem  # Release bitmap
        #bmp.SaveFile('screenshot.png', wx.BITMAP_TYPE_PNG)
        myWxImage = wx.ImageFromBitmap( myBitmap )
        PilImage = Image.new( 'RGB', (myWxImage.GetWidth(), myWxImage.GetHeight()) )
        PilImage.fromstring( myWxImage.GetData() )
        return PilImage

if __name__ == '__main__':
    s = screengrab()
    screen = s.screen()
    screen.show()

Why are unnamed namespaces used and what are their benefits?

Having something in an anonymous namespace means it's local to this translation unit (.cpp file and all its includes) this means that if another symbol with the same name is defined elsewhere there will not be a violation of the One Definition Rule (ODR).

This is the same as the C way of having a static global variable or static function but it can be used for class definitions as well (and should be used rather than static in C++).

All anonymous namespaces in the same file are treated as the same namespace and all anonymous namespaces in different files are distinct. An anonymous namespace is the equivalent of:

namespace __unique_compiler_generated_identifer0x42 {
    ...
}
using namespace __unique_compiler_generated_identifer0x42;

How to remove old Docker containers

For anyone interested, I took the example from qkrijger and turned it into a clear all (stop and remove all)

docker stop `docker ps --no-trunc -aq` ; docker rm `docker ps --no-trunc -aq`

Transparent ARGB hex value

BE AWARE

In HTML/CSS (browser code) the format is #RRGGBBAA with the alpha channel as last two hexadecimal digits.

How can I prevent the textarea from stretching beyond his parent DIV element? (google-chrome issue only)

I'm hoping you are having the same problem that I had... my issue was simple: Make a fixed textarea with locked percentages inside the container (I'm new to CSS/JS/HTML, so bear with me, if I don't get the lingo correct) so that no matter the device it's displaying on, the box filling the container (the table cell) takes up the correct amount of space. Here's how I solved it:

<table width=100%>
    <tr class="idbbs">
        B.S.:
    </tr></br>
    <tr>
        <textarea id="bsinpt"></textarea>
    </tr>
</table>

Then CSS Looks like this...

#bsinpt
{
    color: gainsboro;
    float: none;
    background: black;
    text-align: left;
    font-family: "Helvetica", "Tahoma", "Verdana", "Arial Black", sans-serif;
    font-size: 100%;
  position: absolute;
  min-height: 60%;
  min-width: 88%;
  max-height: 60%;
  max-width: 88%;
  resize: none;
    border-top-color: lightsteelblue;
    border-top-width: 1px;
    border-left-color: lightsteelblue;
    border-left-width: 1px;
    border-right-color: lightsteelblue;
    border-right-width: 1px;
    border-bottom-color: lightsteelblue;
    border-bottom-width: 1px;
}

Sorry for the sloppy code block here, but I had to show you what's important and I don't know how to insert quoted CSS code on this website. In any case, to ensure you see what I'm talking about, the important CSS is less indented here...

What I then did (as shown here) is very specifically tweak the percentages until I found the ones that worked perfectly to fit display, no matter what device screen is used.

Granted, I think the "resize: none;" is overkill, but better safe than sorry and now the consumers will not have anyway to resize the box, nor will it matter what device they are viewing it from.

It works great.

Html.Raw() in ASP.NET MVC Razor view

The accepted answer is correct, but I prefer:

@{int count = 0;} 
@foreach (var item in Model.Resources) 
{ 
    @Html.Raw(count <= 3 ? "<div class=\"resource-row\">" : "")  
    // some code 
    @Html.Raw(count <= 3 ? "</div>" : "")  
    @(count++)
} 

I hope this inspires someone, even though I'm late to the party.

Find closing HTML tag in Sublime Text

There is a shortcut (Ctrl+Shift+A for Windows and Linux users, Command+Shift+A for Mac users) to select the whole block within the currently selected tag.

For example, if you pressed this while your text cursor was within the outer div tag in the code below, all the divs with class selected would be selected.

<div class='current_tag_block'>
  <div class='selected'></div>
  <div class='selected'></div>
  <div class='selected'></div>
  <div class='selected'></div>
</div>

Foreach with JSONArray and JSONObject

Seems like you can't iterate through JSONArray with a for each. You can loop through your JSONArray like this:

for (int i=0; i < arr.length(); i++) {
    arr.getJSONObject(i);
}

Source

SQL Server convert string to datetime

For instance you can use

update tablename set datetimefield='19980223 14:23:05'
update tablename set datetimefield='02/23/1998 14:23:05'
update tablename set datetimefield='1998-12-23 14:23:05'
update tablename set datetimefield='23 February 1998 14:23:05'
update tablename set datetimefield='1998-02-23T14:23:05'

You need to be careful of day/month order since this will be language dependent when the year is not specified first. If you specify the year first then there is no problem; date order will always be year-month-day.

Is There a Better Way of Checking Nil or Length == 0 of a String in Ruby?

Konrad Rudolph has the right answer.

If it really bugs you, monkey patch the String class or add it to a class/module of your choice. It's really not a good practice to monkey patch core objects unless you have a really compelling reason though.

class String
  def self.nilorempty?(string)
    string.nil? || string.empty?
  end
end

Then you can do String.nilorempty? mystring

Simple linked list in C++

link list by using node class and linked list class

this is just an example not the complete functionality of linklist, append function and printing a linklist is explained in the code

code :

#include<iostream>
using namespace std;

Node class

class Node{
    public:
    int data;
    Node* next=NULL;
    Node(int data)
        {
            this->data=data;


        }   
    };

link list class named as ll

class ll{
    public:
        Node* head;

ll(Node* node)
    {
        this->head=node;
    }

void append(int data)
    {
        Node* temp=this->head;
        while(temp->next!=NULL)
            {
                temp=temp->next;
            }
        Node* newnode= new Node(data);
        // newnode->data=data;
        temp->next=newnode;
    }
void print_list()
    {   cout<<endl<<"printing entire link list"<<endl;
        Node* temp= this->head;
        while(temp->next!=NULL)
            {
                cout<<temp->data<<endl;
                temp=temp->next;
            }
        cout<<temp->data<<endl;;

    }
};

main function

int main()
{
  cout<<"hello this is an example of link list in cpp using classes"<<endl;
  ll list1(new Node(1));
  list1.append(2);
  list1.append(3);
  list1.print_list();
  }

thanks ???

screenshot https://i.stack.imgur.com/C2D9y.jpg

Ruby, remove last N characters from a string?

If you're ok with creating class methods and want the characters you chop off, try this:

class String
  def chop_multiple(amount)
    amount.times.inject([self, '']){ |(s, r)| [s.chop, r.prepend(s[-1])] }
  end
end

hello, world = "hello world".chop_multiple 5
hello #=> 'hello '
world #=> 'world'

What is simplest way to read a file into String?

Yes, you can do this in one line (though for robust IOException handling you wouldn't want to).

String content = new Scanner(new File("filename")).useDelimiter("\\Z").next();
System.out.println(content);

This uses a java.util.Scanner, telling it to delimit the input with \Z, which is the end of the string anchor. This ultimately makes the input have one actual token, which is the entire file, so it can be read with one call to next().

There is a constructor that takes a File and a String charSetName (among many other overloads). These two constructor may throw FileNotFoundException, but like all Scanner methods, no IOException can be thrown beyond these constructors.

You can query the Scanner itself through the ioException() method if an IOException occurred or not. You may also want to explicitly close() the Scanner after you read the content, so perhaps storing the Scanner reference in a local variable is best.

See also

Related questions


Third-party library options

For completeness, these are some really good options if you have these very reputable and highly useful third party libraries:

Guava

com.google.common.io.Files contains many useful methods. The pertinent ones here are:

Apache Commons/IO

org.apache.commons.io.IOUtils also offer similar functionality:

  • String toString(InputStream, String encoding)
    • Using the specified character encoding, gets the contents of an InputStream as a String
  • List readLines(InputStream, String encoding)
    • ... as a (raw) List of String, one entry per line

Related questions

Aggregate / summarize multiple variables per group (e.g. sum, mean)

Where is this year() function from?

You could also use the reshape2 package for this task:

require(reshape2)
df_melt <- melt(df1, id = c("date", "year", "month"))
dcast(df_melt, year + month ~ variable, sum)
#  year month         x1           x2
1  2000     1  -80.83405 -224.9540159
2  2000     2 -223.76331 -288.2418017
3  2000     3 -188.83930 -481.5601913
4  2000     4 -197.47797 -473.7137420
5  2000     5 -259.07928 -372.4563522

Checkbox Check Event Listener

Since I don't see the jQuery tag in the OP, here is a javascript only option :

document.addEventListener("DOMContentLoaded", function (event) {
    var _selector = document.querySelector('input[name=myCheckbox]');
    _selector.addEventListener('change', function (event) {
        if (_selector.checked) {
            // do something if checked
        } else {
            // do something else otherwise
        }
    });
});

See JSFIDDLE

MySQL: How to set the Primary Key on phpMyAdmin?

You can view the INDEXES column below where you find a default PRIMARY KEY is set. If it is not set or you want to set any other variable as a PRIMARY KEY then , there is a dialog box below to create an index which asks for a column number ,either way you can create a new one or edit an existing one.The existing one shows up a edit button whee you can go and edit it and you're done save it and you are ready to go

bool to int conversion

Section 6.5.8.6 of the C standard says:

Each of the operators < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to) shall yield 1 if the specified relation is true and 0 if it is false.) The result has type int.

Is the Scala 2.8 collections library a case of "the longest suicide note in history"?

Unfortunately the signature for map that you gave is an incorrect one for map and there is indeed legitimate criticism.

The first criticism is that by subverting the signature for map, we have something that is more general. It is a common error to believe that this is a virtue by default. It isn't. The map function is very well defined as a covariant functor Fx -> (x -> y) -> Fy with adherence to the two laws of composition and identity. Anything else attributed to "map" is a travesty.

The given signature is something else, but it is not map. What I suspect it is trying to be is a specialised and slightly altered version of the "traverse" signature from the paper, The Essence of the Iterator Pattern. Here is its signature:

traverse :: (Traversable t, Applicative f) => (a -> f b) -> t a -> f (t b)

I shall convert it to Scala:

def traverse[A, B](f: A => F[B], a: T[A])(implicit t: Traversable[T], ap: Applicative[F]): F[T[B]

Of course it fails -- it is not general enough! Also, it is slightly different (note that you can get map by running traverse through the Identity functor). However, I suspect that if the library writers were more aware of library generalisations that are well documented (Applicative Programming with Effects precedes the aforementioned), then we wouldn't see this error.

Second, the map function is a special-case in Scala because of its use in for-comprehensions. This unfortunately means that a library designer who is better equipped cannot ignore this error without also sacrificing the syntactic sugar of comprehensions. In other words, if the Scala library designers were to destroy a method, then this is easily ignored, but please not map!

I hope someone speaks up about it, because as it is, it will become harder to workaround the errors that Scala insists on making, apparently for reasons that I have strong objections to. That is, the solution to "the irresponsible objections from the average programmer (i.e. too hard!)" is not "appease them to make it easier for them" but instead, provide pointers and assistance to become better programmers. Myself and Scala's objectives are in contention on this issue, but back to your point.

You were probably making your point, predicting specific responses from "the average programmer." That is, the people who will claim "but it is too complicated!" or some such. These are the Yegges or Blochs that you refer to. My response to these people of the anti-intellectualism/pragmatism movement is quite harsh and I'm already anticipating a barrage of responses, so I will omit it.

I truly hope the Scala libraries improve, or at least, the errors can be safely tucked away in a corner. Java is a language where "trying to do anything useful" is so incredibly costly, that it is often not worth it because the overwhelming amount of errors simply cannot be avoided. I implore Scala to not go down the same path.

Empty ArrayList equals null

No, this will not work. The best you will be able to do is to iterate through all values and check them yourself:

boolean empty = true;
for (Object item : arrayList) {
    if (item != null) {
        empty = false;
        break;
    }
}

How do I break a string across more than one line of code in JavaScript?

The backslash operator is not reliable. Try pasting this function in your browser console:

function printString (){
  const s = "someLongLineOfText\
  ThatShouldNotBeBroken";
  console.log(s);
}

and then run it. Because of the conventional (and correct) indentation within the function, two extra spaces will be included, resulting in someLongLineOfText ThatShouldNotBeBroken.

Even using backticks will not help in this case. Always use the concatenation "+" operator to prevent this type of issue.

Iterating through map in template

As Herman pointed out, you can get the index and element from each iteration.

{{range $index, $element := .}}{{$index}}
{{range $element}}{{.Value}}
{{end}}
{{end}}

Working example:

package main

import (
    "html/template"
    "os"
)

type EntetiesClass struct {
    Name string
    Value int32
}

// In the template, we use rangeStruct to turn our struct values
// into a slice we can iterate over
var htmlTemplate = `{{range $index, $element := .}}{{$index}}
{{range $element}}{{.Value}}
{{end}}
{{end}}`

func main() {
    data := map[string][]EntetiesClass{
        "Yoga": {{"Yoga", 15}, {"Yoga", 51}},
        "Pilates": {{"Pilates", 3}, {"Pilates", 6}, {"Pilates", 9}},
    }

    t := template.New("t")
    t, err := t.Parse(htmlTemplate)
    if err != nil {
        panic(err)
    }

    err = t.Execute(os.Stdout, data)
    if err != nil {
        panic(err)
    }

}

Output:

Pilates
3
6
9

Yoga
15
51

Playground: http://play.golang.org/p/4ISxcFKG7v

Formatting Phone Numbers in PHP

All,

I think I fixed it. Working for current input files and have following 2 functions to get this done!

function format_phone_number:

        function format_phone_number ( $mynum, $mask ) {
        /*********************************************************************/
        /*   Purpose: Return either masked phone number or false             */
        /*     Masks: Val=1 or xxx xxx xxxx                                             */
        /*            Val=2 or xxx xxx.xxxx                                             */
        /*            Val=3 or xxx.xxx.xxxx                                             */
        /*            Val=4 or (xxx) xxx xxxx                                           */
        /*            Val=5 or (xxx) xxx.xxxx                                           */
        /*            Val=6 or (xxx).xxx.xxxx                                           */
        /*            Val=7 or (xxx) xxx-xxxx                                           */
        /*            Val=8 or (xxx)-xxx-xxxx                                           */
        /*********************************************************************/         
        $val_num        = self::validate_phone_number ( $mynum );
        if ( !$val_num && !is_string ( $mynum ) ) { 
            echo "Number $mynum is not a valid phone number! \n";
            return false;
        }   // end if !$val_num
        if ( ( $mask == 1 ) || ( $mask == 'xxx xxx xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '$1 $2 $3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 1
        if ( ( $mask == 2 ) || ( $mask == 'xxx xxx.xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '$1 $2.$3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 2
        if ( ( $mask == 3 ) || ( $mask == 'xxx.xxx.xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '$1.$2.$3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 3
        if ( ( $mask == 4 ) || ( $mask == '(xxx) xxx xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '($1) $2 $3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 4
        if ( ( $mask == 5 ) || ( $mask == '(xxx) xxx.xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '($1) $2.$3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 5
        if ( ( $mask == 6 ) || ( $mask == '(xxx).xxx.xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '($1).$2.$3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 6
        if ( ( $mask == 7 ) || ( $mask == '(xxx) xxx-xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '($1) $2-$3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 7
        if ( ( $mask == 8 ) || ( $mask == '(xxx)-xxx-xxxx' ) ) { 
            $phone = preg_replace('~.*(\d{3})[^\d]*(\d{3})[^\d]*(\d{4}).*~', 
                    '($1)-$2-$3'." \n", $mynum);
            return $phone;
        }   // end if $mask == 8
        return false;       // Returns false if no conditions meet or input
    }  // end function format_phone_number

function validate_phone_number:

        function validate_phone_number ( $phone ) {
        /*********************************************************************/
        /*   Purpose:   To determine if the passed string is a valid phone  */
        /*              number following one of the establish formatting        */
        /*                  styles for phone numbers.  This function also breaks    */
        /*                  a valid number into it's respective components of:      */
        /*                          3-digit area code,                                      */
        /*                          3-digit exchange code,                                  */
        /*                          4-digit subscriber number                               */
        /*                  and validates the number against 10 digit US NANPA  */
        /*                  guidelines.                                                         */
        /*********************************************************************/         
        $format_pattern =   '/^(?:(?:\((?=\d{3}\)))?(\d{3})(?:(?<=\(\d{3})\))'.
                                    '?[\s.\/-]?)?(\d{3})[\s\.\/-]?(\d{4})\s?(?:(?:(?:'.
                                    '(?:e|x|ex|ext)\.?\:?|extension\:?)\s?)(?=\d+)'.
                                    '(\d+))?$/';
        $nanpa_pattern      =   '/^(?:1)?(?(?!(37|96))[2-9][0-8][0-9](?<!(11)))?'.
                                    '[2-9][0-9]{2}(?<!(11))[0-9]{4}(?<!(555(01([0-9]'.
                                    '[0-9])|1212)))$/';

        // Init array of variables to false
        $valid = array('format' =>  false,
                            'nanpa' => false,
                            'ext'       => false,
                            'all'       => false);

        //Check data against the format analyzer
        if ( preg_match ( $format_pattern, $phone, $matchset ) ) {
            $valid['format'] = true;    
        }

        //If formatted properly, continue
        //if($valid['format']) {
        if ( !$valid['format'] ) {
            return false;
        } else {
            //Set array of new components
            $components =   array ( 'ac' => $matchset[1], //area code
                                                            'xc' => $matchset[2], //exchange code
                                                            'sn' => $matchset[3] //subscriber number
                                                            );
            //              $components =   array ( 'ac' => $matchset[1], //area code
            //                                              'xc' => $matchset[2], //exchange code
            //                                              'sn' => $matchset[3], //subscriber number
            //                                              'xn' => $matchset[4] //extension number             
            //                                              );

            //Set array of number variants
            $numbers    =   array ( 'original' => $matchset[0],
                                        'stripped' => substr(preg_replace('[\D]', '', $matchset[0]), 0, 10)
                                        );

            //Now let's check the first ten digits against NANPA standards
            if(preg_match($nanpa_pattern, $numbers['stripped'])) {
                $valid['nanpa'] = true;
            }

            //If the NANPA guidelines have been met, continue
            if ( $valid['nanpa'] ) {
                if ( !empty ( $components['xn'] ) ) {
                    if ( preg_match ( '/^[\d]{1,6}$/', $components['xn'] ) ) {
                        $valid['ext'] = true;
                    }   // end if if preg_match 
                } else {
                    $valid['ext'] = true;
                }   // end if if  !empty
            }   // end if $valid nanpa

            //If the extension number is valid or non-existent, continue
            if ( $valid['ext'] ) {
                $valid['all'] = true;
            }   // end if $valid ext
        }   // end if $valid
        return $valid['all'];
    }   // end functon validate_phone_number

Notice I have this in a class lib, so thus the "self::validate_phone_number" call from the first function/method.

Notice line # 32 of the "validate_phone_number" function where I added the:

            if ( !$valid['format'] ) {
            return false;
        } else {

to get me the false return needed if not valid phone number.

Still need to test this against more data, but working on current data, with current format and I'm using style '8' for this particular data batch.

Also I commented out the "extension" logic as I was constantly getting errors from it, seeing I do not have any of that info in my data.

How do I pause my shell script for a second before continuing?

Use the sleep command.

Example:

sleep .5 # Waits 0.5 second.
sleep 5  # Waits 5 seconds.
sleep 5s # Waits 5 seconds.
sleep 5m # Waits 5 minutes.
sleep 5h # Waits 5 hours.
sleep 5d # Waits 5 days.

One can also employ decimals when specifying a time unit; e.g. sleep 1.5s

Equivalent of LIMIT and OFFSET for SQL Server?

Since nobody provided this code yet:

SELECT TOP @limit f1, f2, f3...
FROM t1
WHERE c1 = v1, c2 > v2...
AND
    t1.id NOT IN
        (SELECT TOP @offset id
         FROM t1
         WHERE c1 = v1, c2 > v2...
         ORDER BY o1, o2...)
ORDER BY o1, o2...

Important points:

  • ORDER BY must be identical
  • @limit can be replaced with number of results to retrieve,
  • @offset is number of results to skip
  • Please compare performance with previous solutions as they may be more efficient
  • this solution duplicates where and order by clauses, and will provide incorrect results if they are out of sync
  • on the other hand order by is there explicitly if that's what's needed

Ansible - Use default if a variable is not defined

In case you using lookup to set default read from environment you have also set the second parameter of default to true:

- set_facts:
    ansible_ssh_user: "{{ lookup('env', 'SSH_USER') | default('foo', true) }}"

You can also concatenate multiple default definitions:

- set_facts:
    ansible_ssh_user: "{{ some_var.split('-')[1] | default(lookup('env','USER'), true) | default('foo') }}"

Convert datetime to Unix timestamp and convert it back in python

This class will cover your needs, you can pass the variable into ConvertUnixToDatetime & call which function you want it to operate based off.

from datetime import datetime
import time

class ConvertUnixToDatetime:
    def __init__(self, date):
        self.date = date

    # Convert unix to date object
    def convert_unix(self):
        unix = self.date

        # Check if unix is a string or int & proceeds with correct conversion
        if type(unix).__name__ == 'str':
            unix = int(unix[0:10])
        else:
            unix = int(str(unix)[0:10])

        date = datetime.utcfromtimestamp(unix).strftime('%Y-%m-%d %H:%M:%S')

        return date

    # Convert date to unix object
    def convert_date(self):
        date = self.date

        # Check if datetime object or raise ValueError
        if type(date).__name__ == 'datetime':
            unixtime = int(time.mktime(date.timetuple()))
        else:
            raise ValueError('You are trying to pass a None Datetime object')
        return type(unixtime).__name__, unixtime


if __name__ == '__main__':

    # Test Date
    date_test = ConvertUnixToDatetime(datetime.today())
    date_test = date_test.convert_date()
    print(date_test)

    # Test Unix
    unix_test = ConvertUnixToDatetime(date_test[1])
    print(unix_test.convert_unix())

How to save an image locally using Python whose URL address I already know?

I wrote a script that does just this, and it is available on my github for your use.

I utilized BeautifulSoup to allow me to parse any website for images. If you will be doing much web scraping (or intend to use my tool) I suggest you sudo pip install BeautifulSoup. Information on BeautifulSoup is available here.

For convenience here is my code:

from bs4 import BeautifulSoup
from urllib2 import urlopen
import urllib

# use this image scraper from the location that 
#you want to save scraped images to

def make_soup(url):
    html = urlopen(url).read()
    return BeautifulSoup(html)

def get_images(url):
    soup = make_soup(url)
    #this makes a list of bs4 element tags
    images = [img for img in soup.findAll('img')]
    print (str(len(images)) + "images found.")
    print 'Downloading images to current working directory.'
    #compile our unicode list of image links
    image_links = [each.get('src') for each in images]
    for each in image_links:
        filename=each.split('/')[-1]
        urllib.urlretrieve(each, filename)
    return image_links

#a standard call looks like this
#get_images('http://www.wookmark.com')

Why does visual studio 2012 not find my tests?

We were using xunit and solution worked for me and the team was deleting the folder %TEMP%\VisualStudioTestExplorerExtensions

Read this thread.

Why is the Visual Studio 2015/2017 Test Runner not discovering my xUnit v2 tests

Calling Member Functions within Main C++

declare it "static" like this:

static void MyClass::printInformation() { return; }

PHP Adding 15 minutes to Time value

Quite easy

$timestring = '09:15:00';
echo date('h:i:s', strtotime($timestring) + (15 * 60));

What are the undocumented features and limitations of the Windows FINDSTR command?

Answer continued from part 1 above - I've run into the 30,000 character answer limit :-(

Limited Regular Expressions (regex) Support
FINDSTR support for regular expressions is extremely limited. If it is not in the HELP documentation, it is not supported.

Beyond that, the regex expressions that are supported are implemented in a completely non-standard manner, such that results can be different then would be expected coming from something like grep or perl.

Regex Line Position anchors ^ and $
^ matches beginning of input stream as well as any position immediately following a <LF>. Since FINDSTR also breaks lines after <LF>, a simple regex of "^" will always match all lines within a file, even a binary file.

$ matches any position immediately preceding a <CR>. This means that a regex search string containing $ will never match any lines within a Unix style text file, nor will it match the last line of a Windows text file if it is missing the EOL marker of <CR><LF>.

Note - As previously discussed, piped and redirected input to FINDSTR may have <CR><LF> appended that is not in the source. Obviously this can impact a regex search that uses $.

Any search string with characters before ^ or after $ will always fail to find a match.

Positional Options /B /E /X
The positional options work the same as ^ and $, except they also work for literal search strings.

/B functions the same as ^ at the start of a regex search string.

/E functions the same as $ at the end of a regex search string.

/X functions the same as having both ^ at the beginning and $ at the end of a regex search string.

Regex word boundary
\< must be the very first term in the regex. The regex will not match anything if any other characters precede it. \< corresponds to either the very beginning of the input, the beginning of a line (the position immediately following a <LF>), or the position immediately following any "non-word" character. The next character need not be a "word" character.

\> must be the very last term in the regex. The regex will not match anything if any other characters follow it. \> corresponds to either the end of input, the position immediately prior to a <CR>, or the position immediately preceding any "non-word" character. The preceding character need not be a "word" character.

Here is a complete list of "non-word" characters, represented as the decimal byte code. Note - this list was compiled on a U.S machine. I do not know what impact other languages may have on this list.

001   028   063   179   204   230
002   029   064   180   205   231
003   030   091   181   206   232
004   031   092   182   207   233
005   032   093   183   208   234
006   033   094   184   209   235
007   034   096   185   210   236
008   035   123   186   211   237
009   036   124   187   212   238
011   037   125   188   213   239
012   038   126   189   214   240
014   039   127   190   215   241
015   040   155   191   216   242
016   041   156   192   217   243
017   042   157   193   218   244
018   043   158   194   219   245
019   044   168   195   220   246
020   045   169   196   221   247
021   046   170   197   222   248
022   047   173   198   223   249
023   058   174   199   224   250
024   059   175   200   226   251
025   060   176   201   227   254
026   061   177   202   228   255
027   062   178   203   229

Regex character class ranges [x-y]
Character class ranges do not work as expected. See this question: Why does findstr not handle case properly (in some circumstances)?, along with this answer: https://stackoverflow.com/a/8767815/1012053.

The problem is FINDSTR does not collate the characters by their byte code value (commonly thought of as the ASCII code, but ASCII is only defined from 0x00 - 0x7F). Most regex implementations would treat [A-Z] as all upper case English capital letters. But FINDSTR uses a collation sequence that roughly corresponds to how SORT works. So [A-Z] includes the complete English alphabet, both upper and lower case (except for "a"), as well as non-English alpha characters with diacriticals.

Below is a complete list of all characters supported by FINDSTR, sorted in the collation sequence used by FINDSTR to establish regex character class ranges. The characters are represented as their decimal byte code value. I believe the collation sequence makes the most sense if the characters are viewed using code page 437. Note - this list was compiled on a U.S machine. I do not know what impact other languages may have on this list.

001
002
003
004
005
006
007
008
014
015
016
017
018           
019
020
021
022
023
024
025
026
027
028
029
030
031
127
039
045
032
255
009
010
011
012
013
033
034
035
036
037
038
040
041
042
044
046
047
058
059
063
064
091
092
093
094
095
096
123
124
125
126
173
168
155
156
157
158
043
249
060
061
062
241
174
175
246
251
239
247
240
243
242
169
244
245
254
196
205
179
186
218
213
214
201
191
184
183
187
192
212
211
200
217
190
189
188
195
198
199
204
180
181
182
185
194
209
210
203
193
207
208
202
197
216
215
206
223
220
221
222
219
176
177
178
170
248
230
250
048
172
171
049
050
253
051
052
053
054
055
056
057
236
097
065
166
160
133
131
132
142
134
143
145
146
098
066
099
067
135
128
100
068
101
069
130
144
138
136
137
102
070
159
103
071
104
072
105
073
161
141
140
139
106
074
107
075
108
076
109
077
110
252
078
164
165
111
079
167
162
149
147
148
153
112
080
113
081
114
082
115
083
225
116
084
117
085
163
151
150
129
154
118
086
119
087
120
088
121
089
152
122
090
224
226
235
238
233
227
229
228
231
237
232
234

Regex character class term limit and BUG
Not only is FINDSTR limited to a maximum of 15 character class terms within a regex, it fails to properly handle an attempt to exceed the limit. Using 16 or more character class terms results in an interactive Windows pop up stating "Find String (QGREP) Utility has encountered a problem and needs to close. We are sorry for the inconvenience." The message text varies slightly depending on the Windows version. Here is one example of a FINDSTR that will fail:

echo 01234567890123456|findstr [0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]

This bug was reported by DosTips user Judago here. It has been confirmed on XP, Vista, and Windows 7.

Regex searches fail (and may hang indefinitely) if they include byte code 0xFF (decimal 255)
Any regex search that includes byte code 0xFF (decimal 255) will fail. It fails if byte code 0xFF is included directly, or if it is implicitly included within a character class range. Remember that FINDSTR character class ranges do not collate characters based on the byte code value. Character <0xFF> appears relatively early in the collation sequence between the <space> and <tab> characters. So any character class range that includes both <space> and <tab> will fail.

The exact behavior changes slightly depending on the Windows version. Windows 7 hangs indefinitely if 0xFF is included. XP doesn't hang, but it always fails to find a match, and occasionally prints the following error message - "The process tried to write to a nonexistent pipe."

I no longer have access to a Vista machine, so I haven't been able to test on Vista.

Regex bug: . and [^anySet] can match End-Of-File
The regex . meta-character should only match any character other than <CR> or <LF>. There is a bug that allows it to match the End-Of-File if the last line in the file is not terminated by <CR> or <LF>. However, the . will not match an empty file.

For example, a file named "test.txt" containing a single line of x, without terminating <CR> or <LF>, will match the following:

findstr /r x......... test.txt

This bug has been confirmed on XP and Win7.

The same seems to be true for negative character sets. Something like [^abc] will match End-Of-File. Positive character sets like [abc] seem to work fine. I have only tested this on Win7.

What is key=lambda

In Python, lambda is a keyword used to define anonymous functions(functions with no name) and that's why they are known as lambda functions.

Basically it is used for defining anonymous functions that can/can't take argument(s) and returns value of data/expression. Let's see an example.

>>> # Defining a lambda function that takes 2 parameters(as integer) and returns their sum
... 
>>> lambda num1, num2: num1 + num2 
<function <lambda> at 0x1004b5de8>
>>> 
>>> # Let's store the returned value in variable & call it(1st way to call)
... 
>>> addition = lambda num1, num2: num1 + num2
>>> addition(62, 5)
67
>>> addition(1700, 29)
1729
>>> 
>>> # Let's call it in other way(2nd way to call, one line call )
... 
>>> (lambda num1, num2: num1 + num2)(120, 1)
121
>>> (lambda num1, num2: num1 + num2)(-68, 2)
-66
>>> (lambda num1, num2: num1 + num2)(-68, 2**3)
-60
>>> 

Now let me give an answer of your 2nd question. The 1st answer is also great. This is my own way to explain with another example.

Suppose we have a list of items(integers and strings with numeric contents) as follows,

nums = ["2", 1, 3, 4, "5", "8", "-1", "-10"]

and I want to sort it using sorted() function, lets see what happens.

>>> nums = ["2", 1, 3, 4, "5", "8", "-1", "-10"]
>>> sorted(nums)
[1, 3, 4, '-1', '-10', '2', '5', '8']
>>>

It didn't give me what I expected as I wanted like below,

['-10', '-1', 1, '2', 3, 4, '5', '8']

It means we need some strategy(so that sorted could treat our string items as an ints) to achieve this. This is why the key keyword argument is used. Please look at the below one.

>>> nums = ["2", 1, 3, 4, "5", "8", "-1", "-10"]
>>> sorted(nums, key=int)
['-10', '-1', 1, '2', 3, 4, '5', '8']
>>> 

Lets use lambda function as a value of key

>>> names = ["Rishikesh", "aman", "Ajay", "Hemkesh", "sandeep", "Darshan", "Virendra", "Shwetabh"]
>>> names2 = sorted(names)
>>> names2
['Ajay', 'Darshan', 'Hemkesh', 'Rishikesh', 'Shwetabh', 'Virendra', 'aman', 'sandeep']
>>> # But I don't want this o/p(here our intention is to treat 'a' same as 'A')
...
>>> names3 = sorted(names, key=lambda name:name.lower())
>>> names3
['Ajay', 'aman', 'Darshan', 'Hemkesh', 'Rishikesh', 'sandeep', 'Shwetabh', 'Virendra']
>>>

You can define your own function(callable) and provide it as value of key.

Dear programers, I have written the below code for you, just try to understand it and comment your explanation. I would be glad to see your explanation(it's simple).

>>> def validator(item):
...     try:
...         return int(item)
...     except:
...         return 0
... 
>>> sorted(['gurmit', "0", 5, 2, 1, "front", -2, "great"], key=validator)
[-2, 'gurmit', '0', 'front', 'great', 1, 2, 5]
>>>

I hope it would be useful.

form with no action and where enter does not reload page

Simply add this event to your text field. It will prevent a submission on pressing Enter, and you're free to add a submit button or call form.submit() as required:

onKeyPress="if (event.which == 13) return false;"

For example:

<input id="txt" type="text" onKeyPress="if (event.which == 13) return false;"></input>

Check whether number is even or odd

You can do like this:

boolean is_odd(int n) {
    return n % 2 == 1 || n % 2 == -1;
}

This is because Java has in its modulo operation the sign of the dividend, the left side: n. So for negatives and positives dividends, the modulo has the sign of them.

Of course, the bitwise operation is faster and optimized, simply document the line of code with two or three short words, which does it for readability.

How do I accomplish an if/else in mustache.js?

This is how you do if/else in Mustache (perfectly supported):

{{#repo}}
  <b>{{name}}</b>
{{/repo}}
{{^repo}}
  No repos :(
{{/repo}}

Or in your case:

{{#author}}
  {{#avatar}}
    <img src="{{avatar}}"/>
  {{/avatar}}
  {{^avatar}}
    <img src="/images/default_avatar.png" height="75" width="75" />
  {{/avatar}}
{{/author}}

Look for inverted sections in the docs: https://github.com/janl/mustache.js

Python `if x is not None` or `if not x is None`?

The is not operator is preferred over negating the result of is for stylistic reasons. "if x is not None:" reads just like English, but "if not x is None:" requires understanding of the operator precedence and does not read like english.

If there is a performance difference my money is on is not, but this almost certainly isn't the motivation for the decision to prefer that technique. It would obviously be implementation-dependent. Since is isn't overridable, it should be easy to optimise out any distinction anyhow.

Ideal way to cancel an executing AsyncTask

The thing is that AsyncTask.cancel() call only calls the onCancel function in your task. This is where you want to handle the cancel request.

Here is a small task I use to trigger an update method

private class UpdateTask extends AsyncTask<Void, Void, Void> {

        private boolean running = true;

        @Override
        protected void onCancelled() {
            running = false;
        }

        @Override
        protected void onProgressUpdate(Void... values) {
            super.onProgressUpdate(values);
            onUpdate();
        }

        @Override
        protected Void doInBackground(Void... params) {
             while(running) {
                 publishProgress();
             }
             return null;
        }
     }

Python TypeError must be str not int

Python comes with numerous ways of formatting strings:

New style .format(), which supports a rich formatting mini-language:

>>> temperature = 10
>>> print("the furnace is now {} degrees!".format(temperature))
the furnace is now 10 degrees!

Old style % format specifier:

>>> print("the furnace is now %d degrees!" % temperature)
the furnace is now 10 degrees!

In Py 3.6 using the new f"" format strings:

>>> print(f"the furnace is now {temperature} degrees!")
the furnace is now 10 degrees!

Or using print()s default separator:

>>> print("the furnace is now", temperature, "degrees!")
the furnace is now 10 degrees!

And least effectively, construct a new string by casting it to a str() and concatenating:

>>> print("the furnace is now " + str(temperature) + " degrees!")
the furnace is now 10 degrees!

Or join()ing it:

>>> print(' '.join(["the furnace is now", str(temperature), "degrees!"]))
the furnace is now 10 degrees!

How to deep watch an array in angularjs?

There are performance consequences to deep-diving an object in your $watch. Sometimes (for example, when changes are only pushes and pops), you might want to $watch an easily calculated value, such as array.length.

jQueryUI modal dialog does not show close button (x)

a solution can be having the close inside your modal

take a look at this simple example

loop through json array jquery

you could also change from the .get() method to the .getJSON() method, jQuery will then parse the string returned as data to a javascript object and/or array that you can then reference like any other javascript object/array.

using your code above, if you changed .get to .getJSON, you should get an alert of [object Object] for each element in the array. If you changed the alert to alert(item.name) you will get the names.

How to find a Java Memory Leak

I use following approach to finding memory leaks in Java. I've used jProfiler with great success, but I believe that any specialized tool with graphing capabilities (diffs are easier to analyze in graphical form) will work.

  1. Start the application and wait until it get to "stable" state, when all the initialization is complete and the application is idle.
  2. Run the operation suspected of producing a memory leak several times to allow any cache, DB-related initialization to take place.
  3. Run GC and take memory snapshot.
  4. Run the operation again. Depending on the complexity of operation and sizes of data that is processed operation may need to be run several to many times.
  5. Run GC and take memory snapshot.
  6. Run a diff for 2 snapshots and analyze it.

Basically analysis should start from greatest positive diff by, say, object types and find what causes those extra objects to stick in memory.

For web applications that process requests in several threads analysis gets more complicated, but nevertheless general approach still applies.

I did quite a number of projects specifically aimed at reducing memory footprint of the applications and this general approach with some application specific tweaks and trick always worked well.

Good way of getting the user's location in Android

Recently refactored to obtain the location of the code, learn some good ideas, and finally achieved a relatively perfect library and Demo.

@Gryphius's answer is good

    //request all valid provider(network/gps)
private boolean requestAllProviderUpdates() {
    checkRuntimeEnvironment();
    checkPermission();

    if (isRequesting) {
        EasyLog.d("Request location update is busy");
        return false;
    }


    long minTime = getCheckTimeInterval();
    float minDistance = getCheckMinDistance();

    if (mMapLocationListeners == null) {
        mMapLocationListeners = new HashMap<>();
    }

    mValidProviders = getValidProviders();
    if (mValidProviders == null || mValidProviders.isEmpty()) {
        throw new IllegalArgumentException("Not available provider.");
    }

    for (String provider : mValidProviders) {
        LocationListener locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                if (location == null) {
                    EasyLog.e("LocationListener callback location is null.");
                    return;
                }
                printf(location);
                mLastProviderTimestamp = location.getTime();

                if (location.getProvider().equals(LocationManager.GPS_PROVIDER)) {
                    finishResult(location);
                } else {
                    doLocationResult(location);
                }

                removeProvider(location.getProvider());
                if (isEmptyValidProviders()) {
                    requestTimeoutMsgInit();
                    removeUpdates();
                }
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {
            }

            @Override
            public void onProviderEnabled(String provider) {
            }

            @Override
            public void onProviderDisabled(String provider) {
            }
        };
        getLocationManager().requestLocationUpdates(provider, minTime, minDistance, locationListener);
        mMapLocationListeners.put(provider, locationListener);
        EasyLog.d("Location request %s provider update.", provider);
    }
    isRequesting = true;
    return true;
}

//remove request update
public void removeUpdates() {
    checkRuntimeEnvironment();

    LocationManager locationManager = getLocationManager();
    if (mMapLocationListeners != null) {
        Set<String> keys = mMapLocationListeners.keySet();
        for (String key : keys) {
            LocationListener locationListener = mMapLocationListeners.get(key);
            if (locationListener != null) {
                locationManager.removeUpdates(locationListener);
                EasyLog.d("Remove location update, provider is " + key);
            }
        }
        mMapLocationListeners.clear();
        isRequesting = false;
    }
}

//Compared with the last successful position, to determine whether you need to filter
private boolean isNeedFilter(Location location) {
    checkLocation(location);

    if (mLastLocation != null) {
        float distance = location.distanceTo(mLastLocation);
        if (distance < getCheckMinDistance()) {
            return true;
        }
        if (location.getAccuracy() >= mLastLocation.getAccuracy()
                && distance < location.getAccuracy()) {
            return true;
        }
        if (location.getTime() <= mLastProviderTimestamp) {
            return true;
        }
    }
    return false;
}

private void doLocationResult(Location location) {
    checkLocation(location);

    if (isNeedFilter(location)) {
        EasyLog.d("location need to filtered out, timestamp is " + location.getTime());
        finishResult(mLastLocation);
    } else {
        finishResult(location);
    }
}

//Return to the finished position
private void finishResult(Location location) {
    checkLocation(location);

    double latitude = location.getLatitude();
    double longitude = location.getLongitude();
    float accuracy = location.getAccuracy();
    long time = location.getTime();
    String provider = location.getProvider();

    if (mLocationResultListeners != null && !mLocationResultListeners.isEmpty()) {
        String format = "Location result:<%f, %f> Accuracy:%f Time:%d Provider:%s";
        EasyLog.i(String.format(format, latitude, longitude, accuracy, time, provider));

        mLastLocation = location;
        synchronized (this) {
            Iterator<LocationResultListener> iterator =  mLocationResultListeners.iterator();
            while (iterator.hasNext()) {
                LocationResultListener listener = iterator.next();
                if (listener != null) {
                    listener.onResult(location);
                }
                iterator.remove();
            }
        }
    }
}

Complete implementation: https://github.com/bingerz/FastLocation/blob/master/fastlocationlib/src/main/java/cn/bingerz/fastlocation/FastLocation.java

1.Thanks @Gryphius solution ideas, I also share the complete code.

2.Each request to complete the location, it is best to removeUpdates, otherwise the phone status bar will always display the positioning icon

CLEAR SCREEN - Oracle SQL Developer shortcut?

Use cl scr on the Sql* command line tool to clear all the matter on the screen.

What is the best IDE to develop Android apps in?

you can use Juno, i just find it. it's fastest than Helios that i worked with that. you can try it.

Server Error in '/' Application. ASP.NET

Looks like this is a very generic message from iis. in my case we enabled integrated security on web config but forgot to change IIS app pool identity. Things to check -

  • go to event viewer on your server and check exact message.
  • -make sure your app pool and web config using same security(E.g Windows,integrated)

Note: this may not help every time but this might be one of the reason for above error message.

Test for multiple cases in a switch, like an OR (||)

You have to switch it!

switch (true) {
    case ( (pageid === "listing-page") || (pageid === ("home-page") ):
        alert("hello");
        break;
    case (pageid === "details-page"):
        alert("goodbye");
        break;
}

How can I solve the error 'TS2532: Object is possibly 'undefined'?

With the release of TypeScript 3.7, optional chaining (the ? operator) is now officially available.

As such, you can simplify your expression to the following:

const data = change?.after?.data();

You may read more about it from that version's release notes, which cover other interesting features released on that version.

Run the following to install the latest stable release of TypeScript.

npm install typescript

That being said, Optional Chaining can be used alongside Nullish Coalescing to provide a fallback value when dealing with null or undefined values

const data = change?.after?.data() ?? someOtherData();

Is it fine to have foreign key as primary key?

It is generally considered bad practise to have a one to one relationship. This is because you could just have the data represented in one table and achieve the same result.

However, there are instances where you may not be able to make these changes to the table you are referencing. In this instance there is no problem using the Foreign key as the primary key. It might help to have a composite key consisting of an auto incrementing unique primary key and the foreign key.

I am currently working on a system where users can log in and generate a registration code to use with an app. For reasons I won't go into I am unable to simply add the columns required to the users table. So I am going down a one to one route with the codes table.

How to Alter a table for Identity Specification is identity SQL Server

You cannot "convert" an existing column into an IDENTITY column - you will have to create a new column as INT IDENTITY:

ALTER TABLE ProductInProduct 
ADD NewId INT IDENTITY (1, 1);

Update:

OK, so there is a way of converting an existing column to IDENTITY. If you absolutely need this - check out this response by Martin Smith with all the gory details.

Reactjs convert html string to jsx

i start using npm package called react-html-parser

Using Lato fonts in my css (@font-face)

Font Squirrel has a wonderful web font generator.

I think you should find what you need here to generate OTF fonts and the needed CSS to use them. It will even support older IE versions.

Java IOException "Too many open files"

Although in most general cases the error is quite clearly that file handles have not been closed, I just encountered an instance with JDK7 on Linux that well... is sufficiently ****ed up to explain here.

The program opened a FileOutputStream (fos), a BufferedOutputStream (bos) and a DataOutputStream (dos). After writing to the dataoutputstream, the dos was closed and I thought everything went fine.

Internally however, the dos, tried to flush the bos, which returned a Disk Full error. That exception was eaten by the DataOutputStream, and as a consequence the underlying bos was not closed, hence the fos was still open.

At a later stage that file was then renamed from (something with a .tmp) to its real name. Thereby, the java file descriptor trackers lost track of the original .tmp, yet it was still open !

To solve this, I had to first flush the DataOutputStream myself, retrieve the IOException and close the FileOutputStream myself.

I hope this helps someone.

BASH Syntax error near unexpected token 'done'

Run cat -v file.sh.

You most likely have a carriage return or no-break space in your file. cat -v will show them as ^M and M-BM- or M- respectively. It will similarly show any other strange characters you might have gotten into your file.

Remove the Windows line breaks with

tr -d '\r' < file.sh > fixedfile.sh

how to convert string into time format and add two hours

Being a fan of the Joda Time library, here's how you can do it that way using a Joda DateTime:

import org.joda.time.format.*;
import org.joda.time.*;

...    

String dateString = "2009-04-17 10:41:33";

// parse the string
DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss");
DateTime dateTime = formatter.parseDateTime(dateString);

// add two hours
dateTime = dateTime.plusHours(2); // easier than mucking about with Calendar and constants

System.out.println(dateTime);

If you still need to use java.util.Date objects before/after this conversion, the Joda DateTime API provides some easy toDate() and toCalendar() methods for easy translation.

The Joda API provides so much more in the way of convenience over the Java Date/Calendar API.

Update value of a nested dictionary of varying depth

I recommend to replace {} by type(v)() in order to propagate object type of any dict subclass stored in u but absent from d. For example, this would preserve types such as collections.OrderedDict:

Python 2:

import collections

def update(d, u):
    for k, v in u.iteritems():
        if isinstance(v, collections.Mapping):
            d[k] = update(d.get(k, type(v)()), v)
        else:
            d[k] = v
    return d

Python 3:

import collections.abc

def update(d, u):
    for k, v in u.items():
        if isinstance(v, collections.abc.Mapping):
            d[k] = update(d.get(k, type(v)()), v)
        else:
            d[k] = v
    return d

How do I check if a variable is of a certain type (compare two types) in C?

As other people have already said this isn't supported in the C language. You could however check the size of a variable using the sizeof() function. This may help you determine if two variables can store the same type of data.

Before you do that, read the comments below.

Defining TypeScript callback type

I came across the same error when trying to add the callback to an event listener. Strangely, setting the callback type to EventListener solved it. It looks more elegant than defining a whole function signature as a type, but I'm not sure if this is the correct way to do this.

class driving {
    // the answer from this post - this works
    // private callback: () => void; 

    // this also works!
    private callback:EventListener;

    constructor(){
        this.callback = () => this.startJump();
        window.addEventListener("keydown", this.callback);
    }

    startJump():void {
        console.log("jump!");
        window.removeEventListener("keydown", this.callback);
    }
}

PHP foreach loop through multidimensional array

If you mean the first and last entry of the array when talking about a.first and a.last, it goes like this:

foreach ($arr_nav as $inner_array) {
    echo reset($inner_array); //apple, orange, pear
    echo end($inner_array); //My Apple, View All Oranges, A Pear
}

arrays in PHP have an internal pointer which you can manipulate with reset, next, end. Retrieving keys/values works with key and current, but using each might be better in many cases..

How to extract custom header value in Web API message handler?

var token = string.Empty;
if (Request.Headers.TryGetValue("MyKey",  out headerValues))
{
    token = headerValues.FirstOrDefault();
}

How to set a cookie to expire in 1 hour in Javascript?

Code :

var now = new Date();
var time = now.getTime();
time += 3600 * 1000;
now.setTime(time);
document.cookie = 
'username=' + value + 
'; expires=' + now.toUTCString() + 
'; path=/';

Change values on matplotlib imshow() graph axis

I had a similar problem and google was sending me to this post. My solution was a bit different and less compact, but hopefully this can be useful to someone.

Showing your image with matplotlib.pyplot.imshow is generally a fast way to display 2D data. However this by default labels the axes with the pixel count. If the 2D data you are plotting corresponds to some uniform grid defined by arrays x and y, then you can use matplotlib.pyplot.xticks and matplotlib.pyplot.yticks to label the x and y axes using the values in those arrays. These will associate some labels, corresponding to the actual grid data, to the pixel counts on the axes. And doing this is much faster than using something like pcolor for example.

Here is an attempt at this with your data:

import matplotlib.pyplot as plt

# ... define 2D array hist as you did

plt.imshow(hist, cmap='Reds')
x = np.arange(80,122,2) # the grid to which your data corresponds
nx = x.shape[0]
no_labels = 7 # how many labels to see on axis x
step_x = int(nx / (no_labels - 1)) # step between consecutive labels
x_positions = np.arange(0,nx,step_x) # pixel count at label position
x_labels = x[::step_x] # labels you want to see
plt.xticks(x_positions, x_labels)
# in principle you can do the same for y, but it is not necessary in your case

Find the min/max element of an array in JavaScript

For big arrays (~107 elements), Math.min and Math.max procuces a RangeError (Maximum call stack size exceeded) in node.js.

For big arrays, a quick & dirty solution is:

Array.prototype.min = function() {
    var r = this[0];
    this.forEach(function(v,i,a){if (v<r) r=v;});
    return r;
};

How do I do top 1 in Oracle?

Use:

SELECT x.*
  FROM (SELECT fname 
          FROM MyTbl) x
 WHERE ROWNUM = 1

If using Oracle9i+, you could look at using analytic functions like ROW_NUMBER() but they won't perform as well as ROWNUM.

Extract substring from a string

The best way to get substring in Android is using (as @user2503849 said) TextUtlis.substring(CharSequence, int, int) method. I can explain why. If you will take a look at the String.substring(int, int) method from android.jar (newest API 22), you will see:

public String substring(int start) {
    if (start == 0) {
        return this;
    }
    if (start >= 0 && start <= count) {
        return new String(offset + start, count - start, value);
    }
    throw indexAndLength(start);
}

Ok, than... How do you think the private constructor String(int, int, char[]) looks like?

String(int offset, int charCount, char[] chars) {
    this.value = chars;
    this.offset = offset;
    this.count = charCount;
}

As we can see it keeps reference to the "old" value char[] array. So, the GC can not free it.

In the newest Java it was fixed:

String(int offset, int charCount, char[] chars) {
    this.value = Arrays.copyOfRange(chars, offset, offset + charCount);
    this.offset = offset;
    this.count = charCount;
}

Arrays.copyOfRange(...) uses native array copying inside.

That's it :)

Best regards!

Cannot install packages using node package manager in Ubuntu

You can also install Nodejs using NVM or Nodejs Version Manager There are a lot of benefits to using a version manager. One of them being you don't have to worry about this issue.


Instructions:


sudo apt-get update
sudo apt-get install build-essential libssl-dev

Once the prerequisite packages are installed, you can pull down the nvm installation script from the project's GitHub page. The version number may be different, but in general, you can download and install it with the following syntax:

curl https://raw.githubusercontent.com/creationix/nvm/v0.16.1/install.sh | sh

This will download the script and run it. It will install the software into a subdirectory of your home directory at ~/.nvm. It will also add the necessary lines to your ~/.profile file to use the file.

To gain access to the nvm functionality, you'll need to log out and log back in again, or you can source the ~/.profile file so that your current session knows about the changes:

source ~/.profile

Now that you have nvm installed, you can install isolated Node.js versions.

To find out the versions of Node.js that are available for installation, you can type:

nvm ls-remote
. . .

v0.11.10
v0.11.11
v0.11.12
v0.11.13
v0.11.14

As you can see, the newest version at the time of this writing is v0.11.14. You can install that by typing:

nvm install 0.11.14

Usually, nvm will switch to use the most recently installed version. You can explicitly tell nvm to use the version we just downloaded by typing:

nvm use 0.11.14

When you install Node.js using nvm, the executable is called node. You can see the version currently being used by the shell by typing:

node -v

The comeplete tutorial can be found here

How to acces external json file objects in vue.js app

I have recently started working on a project using Vue JS, JSON Schema. I am trying to access nested JSON Objects from a JSON Schema file in the Vue app. I tried the below code and now I can load different JSON objects inside different Vue template tags. In the script tag add the below code

import  {JsonObject1name, JsonObject2name} from 'your Json file path';

Now you can access JsonObject1,2 names in data section of export default part as below:

data: () => ({ 
  
  schema: JsonObject1name,
  schema1: JsonObject2name,   
  
  model: {} 
}),

Now you can load the schema, schema1 data inside Vue template according to your requirement. See below code for example :

      <SchemaForm id="unique name representing your Json object1" class="form"  v-model="model" :schema="schema" :components="components">
      </SchemaForm>  

      <SchemaForm id="unique name representing your Json object2" class="form" v-model="model" :schema="schema1" :components="components">
      </SchemaForm>

SchemaForm is the local variable name for @formSchema/native library. I have implemented the data of different JSON objects through forms in different CSS tabs.

I hope this answer helps someone. I can help if there are any questions.

How to get a value of an element by name instead of ID

let startDate = $('[name=daterangepicker_start]').val();
alert(startDate);

Batch Files - Error Handling

I generally find the conditional command concatenation operators much more convenient than ERRORLEVEL.

yourCommand && (
  echo yourCommand was successful
) || (
  echo yourCommand failed
)

There is one complication you should be aware of. The error branch will fire if the last command in the success branch raises an error.

yourCommand && (
  someCommandThatMayFail
) || (
  echo This will fire if yourCommand or someCommandThatMayFail raises an error
)

The fix is to insert a harmless command that is guaranteed to succeed at the end of the success branch. I like to use (call ), which does nothing except set the ERRORLEVEL to 0. There is a corollary (call) that does nothing except set the ERRORLEVEL to 1.

yourCommand && (
  someCommandThatMayFail
  (call )
) || (
  echo This can only fire if yourCommand raises an error
)

See Foolproof way to check for nonzero (error) return code in windows batch file for examples of the intricacies needed when using ERRORLEVEL to detect errors.

C++ Boost: undefined reference to boost::system::generic_category()

g++ -lboost_system -lboost_filesystem userentry.cpp -o userentry

worked perfectly under debian. (boost c++ libraries installed with apt-get).

Adding custom radio buttons in android

I realize this is a belated answer, but looking through developer.android.com, it seems that the Toggle button would be ideal for your situation.

Toggle button image http://developer.android.com/guide/topics/ui/controls/togglebutton.html

And of course you can still use the other suggestions for having a background drawable to get a custom look you want.

<ToggleButton 
    android:id="@+id/togglebutton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/custom_button_background"
    android:textOn="On"
    android:textOff="Off"
    />

Now if you want to go with your final edit and have a "halo" effect around your buttons, you can use another custom selector to do just that.

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="true" > <!-- selected -->
        <shape>
            <solid
                android:color="@android:color/white" />
            <stroke
                android:width="3px"
                android:color="@android:color/holo_blue_bright" />
            <corners
                android:radius="5dp" />
        </shape>
    </item>
    <item> <!-- default -->
        <shape>
            <solid
                android:color="@android:color/white" />
            <stroke
                android:width="1px"
                android:color="@android:color/darker_gray" />
            <corners
                android:radius="5dp" />
        </shape>
    </item> 
</selector>

Maven 3 and JUnit 4 compilation problem: package org.junit does not exist

I had a similar problem of Eclipse compiling my code just fine but Maven failed when compiling the tests every time despite the fact JUnit was in my list of dependencies and the tests were in /src/test/java/.

In my case, I had the wrong version of JUnit in my list of dependencies. I wrote JUnit4 tests (with annotations) but had JUnit 3.8.x as my dependency. Between version 3.8.x and 4 of JUnit they changed the package name from junit.framework to org.junit which is why Maven still breaks compiling using a JUnit jar.

I'm still not entirely sure why Eclipse successfully compiled. It must have its own copy of JUnit4 somewhere in the classpath. Hope this alternative solution is useful to people. I reached this solution after following Arthur's link above.

Excel Reference To Current Cell

I found the best way to handle this (for me) is to use the following:

Dim MyString as String
MyString = Application.ThisCell.Address
Range(MyString).Select

Hope this helps.

How to use multiple databases in Laravel

Using .env >= 5.0 (tested on 5.5)

In .env

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=database1
DB_USERNAME=root
DB_PASSWORD=secret

DB_CONNECTION_SECOND=mysql
DB_HOST_SECOND=127.0.0.1
DB_PORT_SECOND=3306
DB_DATABASE_SECOND=database2
DB_USERNAME_SECOND=root
DB_PASSWORD_SECOND=secret

In config/database.php

'mysql' => [
    'driver'    => env('DB_CONNECTION'),
    'host'      => env('DB_HOST'),
    'port'      => env('DB_PORT'),
    'database'  => env('DB_DATABASE'),
    'username'  => env('DB_USERNAME'),
    'password'  => env('DB_PASSWORD'),
],

'mysql2' => [
    'driver'    => env('DB_CONNECTION_SECOND'),
    'host'      => env('DB_HOST_SECOND'),
    'port'      => env('DB_PORT_SECOND'),
    'database'  => env('DB_DATABASE_SECOND'),
    'username'  => env('DB_USERNAME_SECOND'),
    'password'  => env('DB_PASSWORD_SECOND'),
],

Note: In mysql2 if DB_username and DB_password is same, then you can use env('DB_USERNAME') which is metioned in .env first few lines.

Without .env <5.0

Define Connections

app/config/database.php

return array(

    'default' => 'mysql',

    'connections' => array(

        # Primary/Default database connection
        'mysql' => array(
            'driver'    => 'mysql',
            'host'      => '127.0.0.1',
            'database'  => 'database1',
            'username'  => 'root',
            'password'  => 'secret'
            'charset'   => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix'    => '',
        ),

        # Secondary database connection
        'mysql2' => array(
            'driver'    => 'mysql',
            'host'      => '127.0.0.1',
            'database'  => 'database2',
            'username'  => 'root',
            'password'  => 'secret'
            'charset'   => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix'    => '',
        ),
    ),
);

Schema

To specify which connection to use, simply run the connection() method

Schema::connection('mysql2')->create('some_table', function($table)
{
    $table->increments('id'):
});

Query Builder

$users = DB::connection('mysql2')->select(...);

Eloquent

Set the $connection variable in your model

class SomeModel extends Eloquent {

    protected $connection = 'mysql2';

}

You can also define the connection at runtime via the setConnection method or the on static method:

class SomeController extends BaseController {

    public function someMethod()
    {
        $someModel = new SomeModel;

        $someModel->setConnection('mysql2'); // non-static method

        $something = $someModel->find(1);

        $something = SomeModel::on('mysql2')->find(1); // static method

        return $something;
    }

}

Note Be careful about attempting to build relationships with tables across databases! It is possible to do, but it can come with some caveats and depends on what database and/or database settings you have.


From Laravel Docs

Using Multiple Database Connections

When using multiple connections, you may access each connection via the connection method on the DB facade. The name passed to the connection method should correspond to one of the connections listed in your config/database.php configuration file:

$users = DB::connection('foo')->select(...);

You may also access the raw, underlying PDO instance using the getPdo method on a connection instance:

$pdo = DB::connection()->getPdo();

Useful Links

  1. Laravel 5 multiple database connection FROM laracasts.com
  2. Connect multiple databases in laravel FROM tutsnare.com
  3. Multiple DB Connections in Laravel FROM fideloper.com

Is it possible to override / remove background: none!important with jQuery?

Several problems arise in this question.

Problem #1 - css Specificity (how to override important rule).

According to specification - to override this selector your selector should be 'stronger' which mean it should be!important and have at least 1 id, 1 class and something else - according to you creating this selector is impossible(as you can't alter page content). So the only possible option is to put something into element style which (could be done with js). Note: style rule should also have !important to override.

Problem #2 - background is not a single property - it is a set of properties (see specification)

So you really need to know what are exact names of properties you want to change (in your case it would be background-image)

Problem #3 - How to remove rule already applied (to get previous value)?

Unfortunately css have no mechanism to dismiss rule which qualify for an element - only to override with "stronger" rule. So you won't be able to solve this task with just setting value to something like 'inherit' or 'default' cause value you want to see is neither inherit from parent nor default. To solve this problem you have couple of options.

1) You may already know what is the value you want to apply. For example you can find out this value based on selector used. So in this case you may know that for selector ".image-list li" you need background-image: url("http://placekitten.com/150/50"). If so - just you this script:

jQuery(".image-list li").attr('style', 'background-image: url("http://placekitten.com/150/50") !important; ');

2) If you don't know the value then you can try to alter page content in such a way, that rule you want to dismiss is no longer qualify for element, whereas rule you want to be shown - still qualify. In this case you may temporary remove id from container element. Here is the code:

jQuery("#an-element").attr('id', '');
var backgroundImage = jQuery(".image-list li").css('background-image');
jQuery("#an-element").attr('id', 'an-element');
jQuery(".image-list li").attr('style', 'background-image: ' + backgroundImage + ' !important; ');

Here is link to fiddle http://jsfiddle.net/o3jn9mzo/

3) As third solution - you may generate element which will qualify for desired selection to find out property value - something like this:

var backgroundImage = jQuery("<div class='image-list'><li></li></div>").find('li').css('background-image');
jQuery(".image-list li").attr('style', 'background-image: ' + backgroundImage + ' !important; ');

P.S.: Sorry for really late response.

How to find the Center Coordinate of Rectangle?

We can calculate using mid point of line formula,

centre (x,y) =  new Point((boundRect.tl().x+boundRect.br().x)/2,(boundRect.tl().y+boundRect.br().y)/2)

Convert DateTime in C# to yyyy-MM-dd format and Store it to MySql DateTime Field

GetDateTimeFormats can parse DateTime to different formats. Example to "yyyy-MM-dd" format.

SomeDate.Value.GetDateTimeFormats()[5]

GetDateTimeFormats

WPF Add a Border to a TextBlock

No, you need to wrap your TextBlock in a Border. Example:

<Border BorderThickness="1" BorderBrush="Black">
    <TextBlock ... />
</Border>

Of course, you can set these properties (BorderThickness, BorderBrush) through styles as well:

<Style x:Key="notCalledBorder" TargetType="{x:Type Border}">
    <Setter Property="BorderThickness" Value="1" />
    <Setter Property="BorderBrush" Value="Black" />
</Style>

<Border Style="{StaticResource notCalledBorder}">
    <TextBlock ... />
</Border>

how to check if a datareader is null or empty

if (myReader["Additional"] != DBNull.Value)
{
    ltlAdditional.Text = "contains data";
}
else
{
     ltlAdditional.Text = "is null";
}

How to implement common bash idioms in Python?

Adding to previous answers: check the pexpect module for dealing with interactive commands (adduser, passwd etc.)

Navigation drawer: How do I set the selected item at startup?

First of all create colors for selected item. Here https://stackoverflow.com/a/30594875/1462969 good example. It helps you to change color of icon. For changing background of all selected item add in your values\style.xml file this

  <item name="selectableItemBackground">@drawable/selectable_item_background</item>

Where selectable_item_background should be declared in drawable/selectable_item_background.xml

  <?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/accent_translucent"
      android:state_pressed="true" />
    <item android:drawable="@android:color/transparent" />
   </selector>

Where color can be declared in style.xml

 <color name="accent_translucent">#80FFEB3B</color>

And after this

   // The main navigation menu with user-specific actions
        mainNavigationMenu_ = (NavigationView) findViewById(R.id.main_drawer);
        mainNavigationMenu_.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {
                mainNavigationMenu_.getMenu().findItem(itemId).setChecked(true);
                return true;
            }
        });

As you see I used this mainNavigationMenu_.getMenu().findItem(itemId).setChecked(true); to set selected item. Here navigationView

 <android.support.design.widget.NavigationView
        android:id="@+id/main_drawer"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/header_main_navigation_menu"
        app:itemIconTint="@color/state_list"
        app:itemTextColor="@color/primary"
        app:menu="@menu/main_menu_drawer"/>

blur vs focusout -- any real differences?

The documentation for focusout says (emphasis mine):

The focusout event is sent to an element when it, or any element inside of it, loses focus. This is distinct from the blur event in that it supports detecting the loss of focus on descendant elements (in other words, it supports event bubbling).

The same distinction exists between the focusin and focus events.

Initialize a byte array to a certain value, other than the default null?

var array = Encoding.ASCII.GetBytes(new string(' ', 100));

How to list the tables in a SQLite database file that was opened with ATTACH?

It appears you need to go through the sqlite_master table, like this:

SELECT * FROM dbname.sqlite_master WHERE type='table';

And then manually go through each table with a SELECT or similar to look at the rows.

The .DUMP and .SCHEMA commands doesn't appear to see the database at all.

Adding external library into Qt Creator project

Are you using qmake projects? If so, you can add an external library using the LIBS variable. E.g:

win32:LIBS += path/to/Psapi.lib

Specify JDK for Maven to use

Using this command below also worked for me, using it right after installation of Java 8 from here https://www.oracle.com/java/technologies/javase-downloads.html

export JAVA_HOME=$(/usr/libexec/java_home)

Return a string method in C#

You're currently trying to access a method like a property

Console.WriteLine("{0}",x.fullNameMethod);

It should be

Console.WriteLine("{0}",x.fullNameMethod());

Alternatively you could turn it into a property using

public string fullName
{
   get
   {
        string x = firstName + " " + lastName;
        return x;
   }
}

REST API 404: Bad URI, or Missing Resource?

404 is just the HTTP response code. On top of that, you can provide a response body and/or other headers with a more meaningful error message that developers will see.

Remove duplicate elements from array in Ruby

Just another alternative if anyone cares.

You can also use the to_set method of an array which converts the Array into a Set and by definition, set elements are unique.

[1,2,3,4,5,5,5,6].to_set => [1,2,3,4,5,6]

How to type a new line character in SQL Server Management Studio

This is possible if you have an existing Newline character in the row or another row.

Select the square-box that represents the existing Newline character, copy it (control-C), and then paste it (control-V) where you want it to be.

This is slightly cheesy, but I actually did get it to work in SSMS 2008 and I was not able to get any of the other suggestions (control-enter, alt-13, or any alt-##) to work.

How to update array value javascript?

"But i want to know a better way to do this, if there is one ?"

Yes, since you seem to already have the original object, there's no reason to fetch it again from the Array.

  function Update(keyValue, newKey, newValue)
  {
    keyValue.Key = newKey;
    keyValue.Value = newValue; 
  }

Difference between `constexpr` and `const`

First of all, both are qualifiers in c++. A variable declared const must be initialized and cannot be changed in the future. Hence generally a variable declared as a const will have a value even before compiling.

But, for constexpr it is a bit different.

For constexpr, you can give an expression that could be evaluated during the compilation of the program.

Obviously, the variable declared as constexper cannot be changed in the future just like const.

How to get the last element of an array in Ruby?

One other way, using the splat operator:

*a, last = [1, 3, 4, 5]

STDOUT:
a: [1, 3, 4]
last: 5

What exactly is the function of Application.CutCopyMode property in Excel

By referring this(http://www.excelforum.com/excel-programming-vba-macros/867665-application-cutcopymode-false.html) link the answer is as below:

Application.CutCopyMode=False is seen in macro recorder-generated code when you do a copy/cut cells and paste . The macro recorder does the copy/cut and paste in separate statements and uses the clipboard as an intermediate buffer. I think Application.CutCopyMode = False clears the clipboard. Without that line you will get the warning 'There is a large amount of information on the Clipboard....' when you close the workbook with a large amount of data on the clipboard.

With optimised VBA code you can usually do the copy/cut and paste operations in one statement, so the clipboard isn't used and Application.CutCopyMode = False isn't needed and you won't get the warning.

Flutter command not found

You can do these..

  1. First, open your Mac Terminal
  2. Run 'open -e .bash_profile'
  3. Then add 'PATH="/Volumes/Application/Mobile/flutter/bin:${PATH}" export PATH'
  4. Then Save file & close

Capture HTML Canvas as gif/jpg/png/pdf?

Oops. Original answer was specific to a similar question. This has been revised:

var canvas = document.getElementById("mycanvas");
var img    = canvas.toDataURL("image/png");

with the value in IMG you can write it out as a new Image like so:

document.write('<img src="'+img+'"/>');

How do I run a single test using Jest?

There is now a nice Jest plugin for this called jest-watch-typeahead it makes this process much simpler.

How to send and receive JSON data from a restful webservice using Jersey API

The above problem can be solved by adding the following dependencies in your project, as i was facing the same problem.For more detail answer to this solution please refer link SEVERE:MessageBodyWriter not found for media type=application/xml type=class java.util.HashMap

    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.9.0</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.2</version>
    </dependency>   


    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
        <version>2.25</version>
    </dependency>

Is it possible to ignore one single specific line with Pylint?

I believe you're looking for...

import config.logging_settings  # @UnusedImport

Note the double space before the comment to avoid hitting other formatting warnings.

Also, depending on your IDE (if you're using one), there's probably an option to add the correct ignore rule (e.g., in Eclipse, pressing Ctrl + 1, while the cursor is over the warning, will auto-suggest @UnusedImport).

Installation error: INSTALL_FAILED_OLDER_SDK

Mate, my advice is to change virtual device. Download "Genimotion" application, its easy to use and there are a lot of any devices you need

How to compile without warnings being treated as errors?

Sure, find where -Werror is set and remove that flag. Then warnings will be only warnings.

ggplot legends - change labels, order and title

You need to do two things:

  1. Rename and re-order the factor levels before the plot
  2. Rename the title of each legend to the same title

The code:

dtt$model <- factor(dtt$model, levels=c("mb", "ma", "mc"), labels=c("MBB", "MAA", "MCC"))

library(ggplot2)
ggplot(dtt, aes(x=year, y=V, group = model, colour = model, ymin = lower, ymax = upper)) +
  geom_ribbon(alpha = 0.35, linetype=0)+ 
  geom_line(aes(linetype=model), size = 1) +       
  geom_point(aes(shape=model), size=4)  +      
  theme(legend.position=c(.6,0.8)) +
  theme(legend.background = element_rect(colour = 'black', fill = 'grey90', size = 1, linetype='solid')) +
  scale_linetype_discrete("Model 1") +
  scale_shape_discrete("Model 1") +
  scale_colour_discrete("Model 1")

enter image description here

However, I think this is really ugly as well as difficult to interpret. It's far better to use facets:

ggplot(dtt, aes(x=year, y=V, group = model, colour = model, ymin = lower, ymax = upper)) +
  geom_ribbon(alpha=0.2, colour=NA)+ 
  geom_line() +       
  geom_point()  +      
  facet_wrap(~model)

enter image description here