Programs & Examples On #Synchronize

Why use a ReentrantLock if one can use synchronized(this)?

Synchronized locks does not offer any mechanism of waiting queue in which after the execution of one thread any thread running in parallel can acquire the lock. Due to which the thread which is there in the system and running for a longer period of time never gets chance to access the shared resource thus leading to starvation.

Reentrant locks are very much flexible and has a fairness policy in which if a thread is waiting for a longer time and after the completion of the currently executing thread we can make sure that the longer waiting thread gets the chance of accessing the shared resource hereby decreasing the throughput of the system and making it more time consuming.

"Active Directory Users and Computers" MMC snap-in for Windows 7?

There are new instructions as of the Windows 10 October 2018 update:

Just go to "Manage optional features" in Settings and click "Add a feature" to see the list of available RSAT tools. Select and install the specific RSAT tools you need. To see installation progress, click the Back button to view status on the "Manage optional features" page.

Source: https://www.microsoft.com/en-us/download/details.aspx?id=45520

fetch from origin with deleted remote branches?

If git fetch -p origin does not work for some reason (like because the origin repo no longer exists or you are unable to reach it), another solution is to remove the information which is stored locally on that branch by doing from the root of the repo:

rm .git/refs/remotes/origin/DELETED_BRANCH

or if it is stored in the file .git/packed-refs by deleting the corresponding line which is like

7a9930974b02a3b31cb2ebd17df6667514962685 refs/remotes/origin/DELETED_BRANCH

What's the difference between unit tests and integration tests?

Unit test is usually done for a single functionality implemented in Software module. The scope of testing is entirely within this SW module. Unit test never fulfils the final functional requirements. It comes under whitebox testing methodology..

Whereas Integration test is done to ensure the different SW module implementations. Testing is usually carried out after module level integration is done in SW development.. This test will cover the functional requirements but not enough to ensure system validation.

Convert bytes to a string

try this

bytes.fromhex('c3a9').decode('utf-8') 

Multiplication on command line terminal

Internal Methods

Bash supports arithmetic expansion with $(( expression )). For example:

$ echo $(( 5 * 5 ))
25

External Methods

A number of utilities provide arithmetic, including bc and expr.

$ echo '5 * 5' | /usr/bin/bc
25

$ /usr/bin/expr 5 \* 5
25

How to re-enable right click so that I can inspect HTML elements in Chrome?

The easiest way I found is to open the webpage in Read mode (browser that supports read mode like Safari, Firefox etc) and then copy as usual

How to save traceback / sys.exc_info() values in a variable?

The object can be used as a parameter in Exception.with_traceback() function:

except Exception as e:
    tb = sys.exc_info()
    print(e.with_traceback(tb[2]))

"Rate This App"-link in Google Play store app on the phone

You can always call getInstalledPackages() from the PackageManager class and check to make sure the market class is installed. You could also use queryIntentActivities() to make sure that the Intent you construct will be able to be handled by something, even if it's not the market application. This is probably the best thing to do actually because its the most flexible and robust.

You can check if the market app is there by

Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setData(Uri.parse("market://search?q=foo"));
PackageManager pm = getPackageManager();
List<ResolveInfo> list = pm.queryIntentActivities(intent, 0);

If the list has at least one entry, the Market's there.

You can use the following to launch Android Market on your application's page, it's a bit more automated:

Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse("market://details?id=" + getPackageName()));
startActivity(i);

If you want to test this on your emulator you probably you don't have the market installed on it : see these links for more details:

How To Enable the Android Market in the Google Android Emulator

Installing Google Play on Android Emulator

Preferred method to store PHP arrays (json_encode vs serialize)

Depends on your priorities.

If performance is your absolute driving characteristic, then by all means use the fastest one. Just make sure you have a full understanding of the differences before you make a choice

  • Unlike serialize() you need to add extra parameter to keep UTF-8 characters untouched: json_encode($array, JSON_UNESCAPED_UNICODE) (otherwise it converts UTF-8 characters to Unicode escape sequences).
  • JSON will have no memory of what the object's original class was (they are always restored as instances of stdClass).
  • You can't leverage __sleep() and __wakeup() with JSON
  • By default, only public properties are serialized with JSON. (in PHP>=5.4 you can implement JsonSerializable to change this behavior).
  • JSON is more portable

And there's probably a few other differences I can't think of at the moment.

A simple speed test to compare the two

<?php

ini_set('display_errors', 1);
error_reporting(E_ALL);

// Make a big, honkin test array
// You may need to adjust this depth to avoid memory limit errors
$testArray = fillArray(0, 5);

// Time json encoding
$start = microtime(true);
json_encode($testArray);
$jsonTime = microtime(true) - $start;
echo "JSON encoded in $jsonTime seconds\n";

// Time serialization
$start = microtime(true);
serialize($testArray);
$serializeTime = microtime(true) - $start;
echo "PHP serialized in $serializeTime seconds\n";

// Compare them
if ($jsonTime < $serializeTime) {
    printf("json_encode() was roughly %01.2f%% faster than serialize()\n", ($serializeTime / $jsonTime - 1) * 100);
}
else if ($serializeTime < $jsonTime ) {
    printf("serialize() was roughly %01.2f%% faster than json_encode()\n", ($jsonTime / $serializeTime - 1) * 100);
} else {
    echo "Impossible!\n";
}

function fillArray( $depth, $max ) {
    static $seed;
    if (is_null($seed)) {
        $seed = array('a', 2, 'c', 4, 'e', 6, 'g', 8, 'i', 10);
    }
    if ($depth < $max) {
        $node = array();
        foreach ($seed as $key) {
            $node[$key] = fillArray($depth + 1, $max);
        }
        return $node;
    }
    return 'empty';
}

JsonMappingException: No suitable constructor found for type [simple type, class ]: can not instantiate from JSON object

Thumb Rule: Add a default constructor for each class you used as a mapping class. You missed this and issue arise!
Simply add default constructor and it should work.

How To Use DateTimePicker In WPF?

There is DatePicker in WPF Tool Kit, but I have not seen DateTime Picker in WPF ToolKit. So I don't know what kind of DateTimePicker control John is talking about.

Alter column in SQL Server

I think you want this syntax:

ALTER TABLE tb_TableName  
add constraint cnt_Record_Status Default '' for Record_Status

Based on some of your comments, I am going to guess that you might already have null values in your table which is causing the alter of the column to not null to fail. If that is the case, then you should run an UPDATE first. Your script will be:

update tb_TableName
set Record_Status  = ''
where Record_Status is null

ALTER TABLE tb_TableName
ALTER COLUMN Record_Status VARCHAR(20) NOT NULL

ALTER TABLE tb_TableName
ADD CONSTRAINT DEF_Name DEFAULT '' FOR Record_Status

See SQL Fiddle with demo

Find records from one table which don't exist in another

There's several different ways of doing this, with varying efficiency, depending on how good your query optimiser is, and the relative size of your two tables:

This is the shortest statement, and may be quickest if your phone book is very short:

SELECT  *
FROM    Call
WHERE   phone_number NOT IN (SELECT phone_number FROM Phone_book)

alternatively (thanks to Alterlife)

SELECT *
FROM   Call
WHERE  NOT EXISTS
  (SELECT *
   FROM   Phone_book
   WHERE  Phone_book.phone_number = Call.phone_number)

or (thanks to WOPR)

SELECT * 
FROM   Call
LEFT OUTER JOIN Phone_Book
  ON (Call.phone_number = Phone_book.phone_number)
  WHERE Phone_book.phone_number IS NULL

(ignoring that, as others have said, it's normally best to select just the columns you want, not '*')

How to print a two dimensional array?

I am also a beginner and I've just managed to crack this using two nested for loops.

I looked at the answers here and tbh they're a bit advanced for me so I thought I'd share mine to help all the other newbies out there.

P.S. It's for a Whack-A-Mole game hence why the array is called 'moleGrid'.

public static void printGrid() {
    for (int i = 0; i < moleGrid.length; i++) {
        for (int j = 0; j < moleGrid[0].length; j++) {
            if (j == 0 || j % (moleGrid.length - 1) != 0) {
                System.out.print(moleGrid[i][j]);
            }
            else {
                System.out.println(moleGrid[i][j]);
            }
         }
     }
}

Hope it helps!

Convert Json string to Json object in Swift 4

The problem is that you thought your jsonString is a dictionary. It's not.

It's an array of dictionaries. In raw json strings, arrays begin with [ and dictionaries begin with {.


I used your json string with below code :

let string = "[{\"form_id\":3465,\"canonical_name\":\"df_SAWERQ\",\"form_name\":\"Activity 4 with Images\",\"form_desc\":null}]"
let data = string.data(using: .utf8)!
do {
    if let jsonArray = try JSONSerialization.jsonObject(with: data, options : .allowFragments) as? [Dictionary<String,Any>]
    {
       print(jsonArray) // use the json here     
    } else {
        print("bad json")
    }
} catch let error as NSError {
    print(error)
}

and I am getting the output :

[["form_desc": <null>, "form_name": Activity 4 with Images, "canonical_name": df_SAWERQ, "form_id": 3465]]

Accessing a matrix element in the "Mat" object (not the CvMat object) in OpenCV C++

For cv::Mat_<T> mat just use mat(row, col)

Accessing elements of a matrix with specified type cv::Mat_< _Tp > is more comfortable, as you can skip the template specification. This is pointed out in the documentation as well.

code:

cv::Mat1d mat0 = cv::Mat1d::zeros(3, 4);
std::cout << "mat0:\n" << mat0 << std::endl;
std::cout << "element: " << mat0(2, 0) << std::endl;
std::cout << std::endl;

cv::Mat1d mat1 = (cv::Mat1d(3, 4) <<
    1, NAN, 10.5, NAN,
    NAN, -99, .5, NAN,
    -70, NAN, -2, NAN);
std::cout << "mat1:\n" << mat1 << std::endl;
std::cout << "element: " << mat1(0, 2) << std::endl;
std::cout << std::endl;

cv::Mat mat2 = cv::Mat(3, 4, CV_32F, 0.0);
std::cout << "mat2:\n" << mat2 << std::endl;
std::cout << "element: " << mat2.at<float>(2, 0) << std::endl;
std::cout << std::endl;

output:

mat0:
[0, 0, 0, 0;
 0, 0, 0, 0;
 0, 0, 0, 0]
element: 0

mat1:
[1, nan, 10.5, nan;
 nan, -99, 0.5, nan;
 -70, nan, -2, nan]
element: 10.5

mat2:
[0, 0, 0, 0;
 0, 0, 0, 0;
 0, 0, 0, 0]
element: 0

Entity Framework change connection at runtime

I wanted to have multiple datasources in the app config. So after setting up a section in the app.config i swaped out the datasource and then pass it into the dbcontext as the connection string.

//Get the key/value connection string from app config  
var sect = (NameValueCollection)ConfigurationManager.GetSection("section");  
var val = sect["New DataSource"].ToString();

//Get the original connection string with the full payload  
var entityCnxStringBuilder = new EntityConnectionStringBuilder(ConfigurationManager.ConnectionStrings["OriginalStringBuiltByADO.Net"].ConnectionString);     

//Swap out the provider specific connection string  
entityCnxStringBuilder.ProviderConnectionString = val;

//Return the payload with the change in connection string.   
return entityCnxStringBuilder.ConnectionString;

This took me a bit to figure out. I hope it helps someone out. I was making it way too complicated. before this.

Why can't I declare static methods in an interface?

Since static methods can not be inherited . So no use placing it in the interface. Interface is basically a contract which all its subscribers have to follow . Placing a static method in interface will force the subscribers to implement it . which now becomes contradictory to the fact that static methods can not be inherited .

ArrayList insertion and retrieval order

Yes, ArrayList is an ordered collection and it maintains the insertion order.

Check the code below and run it:

public class ListExample {

    public static void main(String[] args) {
        List<String> myList = new ArrayList<String>();
        myList.add("one");
        myList.add("two");
        myList.add("three");
        myList.add("four");
        myList.add("five");
    
        System.out.println("Inserted in 'order': ");
        printList(myList);
        System.out.println("\n");
        System.out.println("Inserted out of 'order': ");

        // Clear the list
        myList.clear();
    
        myList.add("four");
        myList.add("five");
        myList.add("one");
        myList.add("two");
        myList.add("three");
    
        printList(myList);
    }

    private static void printList(List<String> myList) {
        for (String string : myList) {
            System.out.println(string);
        }
    }
}

Produces the following output:

Inserted in 'order': 
one
two
three
four
five


Inserted out of 'order': 
four
five
one
two
three

For detailed information, please refer to documentation: List (Java Platform SE7)

What's the difference between process.cwd() vs __dirname?

As per node js doc process.cwd()

cwd is a method of global object process, returns a string value which is the current working directory of the Node.js process.

As per node js doc __dirname

The directory name of current script as a string value. __dirname is not actually a global but rather local to each module.

Let me explain with example,

suppose we have a main.js file resides inside C:/Project/main.js and running node main.js both these values return same file

or simply with following folder structure

Project 
+-- main.js
+--lib
   +-- script.js

main.js

console.log(process.cwd())
// C:\Project
console.log(__dirname)
// C:\Project
console.log(__dirname===process.cwd())
// true

suppose we have another file script.js files inside a sub directory of project ie C:/Project/lib/script.js and running node main.js which require script.js

main.js

require('./lib/script.js')
console.log(process.cwd())
// C:\Project
console.log(__dirname)
// C:\Project
console.log(__dirname===process.cwd())
// true

script.js

console.log(process.cwd())
// C:\Project
console.log(__dirname)
// C:\Project\lib
console.log(__dirname===process.cwd())
// false

Counting the occurrences / frequency of array elements

Here's a classic old school method for counting arrays.

var arr = [5, 5, 5, 2, 2, 2, 2, 2, 9, 4];
var counted = [], count = [];
var i = 0, j = 0, k = 0;
while (k < arr.length) {
    if (counted.indexOf(arr[k]) < 0) {
        counted[i] = arr[k];
        count[i] = 0;
        for (j = 0; j < arr.length; j++) {
            if (counted[i] == arr[j]) {
                count[i]++;
            }
        }
        i++;
    } else {
        k++;
    }
}

You can sort it first if you want an alphabetical result, but if you want to preserve the order in which the data was entered then give this a try. Nested loops may be a bit slower than some of the other methods on this page.

Is it possible to assign numeric value to an enum in Java?

I realize this is an older question, but it comes up first in a Google search, and among the excellent answers provided, I didn't see anything fully comprehensive, so I did a little more digging and I ended up writing an enum class that not only allowed me to assign multiple custom values to the enum constants, I even added a method that allows me to assign values to them on the fly during code execution.

This enum class is for a "server" program that I run on a Raspberry Pi. The program receives commands from a client then it executes terminal commands that make adjustments to a webcam that is affixed to my 3D printer.

Using the Linux program 'v4l2-ctl' on the Pi, you can extract all of the possible adjustment commands for a given attached webcam, which also provides the setting datatype, the min and max values, the number of value steps in a given value range etc., so I took all of those and put them in an enum and created an enum interface that makes it easy to both set and get values for each command as well as a simple method to get the actual terminal command that is executed (using the Process and Runtime classes) in order to adjust the setting.

It is a rather large class and I apologize for that, but for me, it's always easier to learn something when I can see it working in full context, so I decided not to scale it down. However, even though it's large, it is definitely simple and it should be obvious what's happening in the class with minimal effort.

package constants;

import java.util.HashMap;
import java.util.Map;

public enum PICam {
    BRIGHTNESS                  ("brightness",                  0,      "int",      0,      100,    1,  50),
    CONTRAST                    ("contrast",                    1,      "int",      100,    100,    1,  0),
    SATURATION                  ("saturation",                  2,      "int",      100,    100,    1,  0),
    RED_BALANCE                 ("red_balance",                 3,      "intmenu",  1,      7999,   1,  1000),
    BLUE_BALANCE                ("blue_balance",                4,      "int",      1,      7999,   1,  1000),
    HORIZONTAL_FLIP             ("horizontal_flip",             5,      "bool",     0,      1,      1,  0),
    VERTICAL_FLIP               ("vertical_flip",               6,      "bool",     0,      1,      1,  0),
    POWER_LINE_FREQUENCY        ("power_line_frequency",        7,      "menu",     0,      3,      1,  1),
    SHARPNESS                   ("sharpness",                   8,      "int",      100,    100,    1,  0),
    COLOR_EFFECTS               ("color_effects",               9,      "menu",     0,      15,     1,  0),
    ROTATE                      ("rotate",                      10,     "int",      0,      360,    90, 0),
    COLOR_EFFECTS_CBCR          ("color_effects_cbcr",          11,     "int",      0,      65535,  1,  32896),
    VIDEO_BITRATE_MODE          ("video_bitrate_mode",          12,     "menu",     0,      1,      1,  0),
    VIDEO_BITRATE               ("video_bitrate",               13,     "int",      25000,  25000000,   25000,  10000000),
    REPEAT_SEQUENCE_HEADER      ("repeat_sequence_header",      14,     "bool",     0,      1,      1,  0),
    H264_I_FRAME_PERIOD         ("h_264_i_frame_period",        15,     "int",      0,      2147483647,1,   60),
    H264_LEVEL                  ("h_264_level",                 16,     "menu",     0,      11,     1,  11),
    H264_PROFILE                ("h_264_profile",               17,     "menu",     0,      4,      1,  4),
    AUTO_EXPOSURE               ("auto_exposure",               18,     "menu",     0,      3,      1,  0),
    EXPOSURE_TIME_ABSOLUTE      ("exposure_time_absolute",      19,     "int",      1,      10000,  1,  1000),
    EXPOSURE_DYNAMIC_FRAMERATE  ("exposure_dynamic_framerate",  20,     "bool",     0,      1,      1,  0),
    AUTO_EXPOSURE_BIAS          ("auto_exposure_bias",          21,     "intmenu",  0,      24,     1,  12),
    WHITE_BALANCE_AUTO_PRESET   ("white_balance_auto_preset",   22,     "menu",     0,      9,      1,  1),
    IMAGE_STABILIZATION         ("image_stabilization",         23,     "bool",     0,      1,      1,  0),
    ISO_SENSITIVITY             ("iso_sensitivity",             24,     "intmenu",  0,      4,      1,  0),
    ISO_SENSITIVITY_AUTO        ("iso_sensitivity_auto",        25,     "menu",     0,      1,      1,  1),
    EXPOSURE_METERING_MODE      ("exposure_metering_mode",      26,     "menu",     0,      2,      1,  0),
    SCENE_MODE                  ("scene_mode",                  27,     "menu",     0,      13,     1,  0),
    COMPRESSION_QUALITY         ("compression_quality",         28,     "int",      1,      100,    1,  30);


    private static final Map<String, PICam>    LABEL_MAP       = new HashMap<>();
    private static final Map<Integer, PICam>   INDEX_MAP       = new HashMap<>();
    private static final Map<String, PICam>    TYPE_MAP        = new HashMap<>();
    private static final Map<Integer, PICam>   MIN_MAP         = new HashMap<>();
    private static final Map<Integer, PICam>   MAX_MAP         = new HashMap<>();
    private static final Map<Integer, PICam>   STEP_MAP        = new HashMap<>();
    private static final Map<Integer, PICam>   DEFAULT_MAP     = new HashMap<>();
    private static final Map<Integer, Integer> THIS_VALUE_MAP  = new HashMap<>();

    private static final String                baseCommandLine = "/usr/bin/v4l2-ctl -d /dev/video0 --set-ctrl=";

    static {
        for (PICam e: values()) {
            LABEL_MAP.put(e.label, e);
            INDEX_MAP.put(e.index, e);
            TYPE_MAP.put(e.type, e);
            MIN_MAP.put(e.min, e);
            MAX_MAP.put(e.max, e);
            STEP_MAP.put(e.step, e);
            DEFAULT_MAP.put(e.defaultValue, e);
        }
    }

    public final String label;
    public final int index;
    public final String type;
    public final int min;
    public final int max;
    public final int step;
    public final int defaultValue;

    private PICam(String label, int index, String type, int min, int max, int step, int defaultValue) {
        this.label = label;
        this.index = index;
        this.type = type;
        this.min = min;
        this.max = max;
        this.step = step;
        this.defaultValue = defaultValue;
    }

    public static void setValue(Integer index, Integer value) {
        if (THIS_VALUE_MAP.containsKey(index)) THIS_VALUE_MAP.replace(index, value);
        else THIS_VALUE_MAP.put(index, value);
    }

    public Integer getValue (Integer index) {
        return THIS_VALUE_MAP.getOrDefault(index, null);
    }

    public static PICam getLabel(String label) {
        return LABEL_MAP.get(label);
    }

    public static PICam getType(String type) {
        return TYPE_MAP.get(type);
    }

    public static PICam getMin(int min) {
        return MIN_MAP.get(min);
    }

    public static PICam getMax(int max) {
        return MAX_MAP.get(max);
    }

    public static PICam getStep(int step) {
        return STEP_MAP.get(step);
    }

    public static PICam getDefault(int defaultValue) {
        return DEFAULT_MAP.get(defaultValue);
    }

    public static String getCommandFor(int index, int newValue) {
        PICam picam = INDEX_MAP.get(index);
        String commandValue = "";
        if ("bool".equals(picam.type)) {
            commandValue = (newValue == 0) ? "false" : "true";
        }
        else {
            commandValue = String.valueOf(newValue);
        }
        return baseCommandLine + INDEX_MAP.get(index).label + "=" + commandValue;
    }

    public static String getCommandFor(PICam picam, Integer newValue) {
        String commandValue = "";
        if ("bool".equals(picam.type)) {
            commandValue = (newValue == 0) ? "false" : "true";
        }
        else {
            commandValue = String.valueOf(newValue);
        }
        return baseCommandLine + INDEX_MAP.get(picam.index).label + "=" + commandValue;
    }

    public static String getCommandFor(PICam piCam) {
        int    newValue     = piCam.defaultValue;
        String commandValue = "";
        if ("bool".equals(piCam.type)) {
            commandValue = (newValue == 0) ? "false" : "true";
        }
        else {
            commandValue = String.valueOf(newValue);
        }
        return baseCommandLine + piCam.label + "=" + commandValue;
    }

    public static String getCommandFor(Integer index) {
        PICam piCam = INDEX_MAP.get(index);
        int    newValue     = piCam.defaultValue;
        String commandValue = "";
        if ("bool".equals(piCam.type)) {
            commandValue = (newValue == 0) ? "false" : "true";
        }
        else {
            commandValue = String.valueOf(newValue);
        }
        return baseCommandLine + piCam.label + "=" + commandValue;
    }
}

Here are some ways that the class can be interacted with:

This code:

public static void test() {
    PICam.setValue(0,127); //Set brightness to 125
    PICam.setValue(PICam.SHARPNESS,143); //Set sharpness to 125
    String command1 = PICam.getSetCommandStringFor(PICam.BRIGHTNESS); //Get command line string to include the brightness value that we previously set referencing it by enum constant.
    String command2 = PICam.getSetCommandStringFor(0); //Get command line string to include the brightness value that we previously set referencing it by index number.
    String command3 = PICam.getDefaultCamString(PICam.BRIGHTNESS); //Get command line string with the default value
    String command4 = PICam.getSetCommandStringFor(PICam.SHARPNESS); //Get command line string with the sharpness value that we previously set.
    String command5 = PICam.getDefaultCamString(PICam.SHARPNESS); //Get command line string with the default sharpness value.
    System.out.println(command1);
    System.out.println(command2);
    System.out.println(command3);
    System.out.println(command4);
    System.out.println(command5);
}

Produces these results:

/usr/bin/v4l2-ctl -d /dev/video0 --set-ctrl=brightness=127
/usr/bin/v4l2-ctl -d /dev/video0 --set-ctrl=brightness=127
/usr/bin/v4l2-ctl -d /dev/video0 --set-ctrl=brightness=50
/usr/bin/v4l2-ctl -d /dev/video0 --set-ctrl=sharpness=143
/usr/bin/v4l2-ctl -d /dev/video0 --set-ctrl=sharpness=0

Equivalent of LIMIT and OFFSET for SQL Server?

This feature is now made easy in SQL Server 2012. This is working from SQL Server 2012 onwards.

Limit with offset to select 11 to 20 rows in SQL Server:

SELECT email FROM emailTable 
WHERE user_id=3
ORDER BY Id
OFFSET 10 ROWS
FETCH NEXT 10 ROWS ONLY;
  • ORDER BY: required
  • OFFSET: optional number of skipped rows
  • NEXT: required number of next rows

Reference: https://docs.microsoft.com/en-us/sql/t-sql/queries/select-order-by-clause-transact-sql

How to test that no exception is thrown?

I stumbled upon this because of SonarQube's rule "squid:S2699": "Add at least one assertion to this test case."

I had a simple test whose only goal was to go through without throwing exceptions.

Consider this simple code:

public class Printer {

    public static void printLine(final String line) {
        System.out.println(line);
    }
}

What kind of assertion can be added to test this method? Sure, you can make a try-catch around it, but that is only code bloat.

The solution comes from JUnit itself.

In case no exception is thrown and you want to explicitly illustrate this behaviour, simply add expected as in the following example:

@Test(expected = Test.None.class /* no exception expected */)
public void test_printLine() {
    Printer.printLine("line");
}

Test.None.class is the default for the expected value.

How can I pass a Bitmap object from one activity to another

All of the above solutions doesn't work for me, Sending bitmap as parceableByteArray also generates error android.os.TransactionTooLargeException: data parcel size.

Solution

  1. Saved the bitmap in internal storage as:
public String saveBitmap(Bitmap bitmap) {
        String fileName = "ImageName";//no .png or .jpg needed
        try {
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
            FileOutputStream fo = openFileOutput(fileName, Context.MODE_PRIVATE);
            fo.write(bytes.toByteArray());
            // remember close file output
            fo.close();
        } catch (Exception e) {
            e.printStackTrace();
            fileName = null;
        }
        return fileName;
    }
  1. and send in putExtra(String) as
Intent intent = new Intent(ActivitySketcher.this,ActivityEditor.class);
intent.putExtra("KEY", saveBitmap(bmp));
startActivity(intent);
  1. and Receive it in other activity as:
if(getIntent() != null){
  try {
           src = BitmapFactory.decodeStream(openFileInput("myImage"));
       } catch (FileNotFoundException e) {
            e.printStackTrace();
      }

 }


VBA Convert String to Date

Try using Replace to see if it will work for you. The problem as I see it which has been mentioned a few times above is the CDate function is choking on the periods. You can use replace to change them to slashes. To answer your question about a Function in vba that can parse any date format, there is not any you have very limited options.

Dim current as Date, highest as Date, result() as Date 
For Each itemDate in DeliveryDateArray
    Dim tempDate As String
    itemDate = IIf(Trim(itemDate) = "", "0", itemDate) 'Added per OP's request.
    tempDate = Replace(itemDate, ".", "/")
    current = Format(CDate(tempDate),"dd/mm/yyyy")
    if current > highest then 
        highest = current 
    end if 
    ' some more operations an put dates into result array 
Next itemDate 
'After activating final sheet... 
Range("A1").Resize(UBound(result), 1).Value = Application.Transpose(result) 

How to return PDF to browser in MVC?

I know this question is old but I thought I would share this as I could not find anything similar.

I wanted to create my views/models as normal using Razor and have them rendered as Pdfs.

This way I had control over the pdf presentation using standard html output rather than figuring out how to layout the document using iTextSharp.

The project and source code is available here with nuget installation instructions:

https://github.com/andyhutch77/MvcRazorToPdf

Install-Package MvcRazorToPdf

Ignore <br> with CSS?

You can simply convert it in a comment..

Or you can do this:

br {
display: none;
}

But if you do not want it why are you puting that there?

Attach a file from MemoryStream to a MailMessage in C#

If all you're doing is attaching a string, you could do it in just 2 lines:

mail.Attachments.Add(Attachment.CreateAttachmentFromString("1,2,3", "text/csv");
mail.Attachments.Last().ContentDisposition.FileName = "filename.csv";

I wasn't able to get mine to work using our mail server with StreamWriter.
I think maybe because with StreamWriter you're missing a lot of file property information and maybe our server didn't like what was missing.
With Attachment.CreateAttachmentFromString() it created everything I needed and works great!

Otherwise, I'd suggest taking your file that is in memory and opening it using MemoryStream(byte[]), and skipping the StreamWriter all together.

Is there a performance difference between a for loop and a for-each loop?

The following code:

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;

interface Function<T> {
    long perform(T parameter, long x);
}

class MyArray<T> {

    T[] array;
    long x;

    public MyArray(int size, Class<T> type, long x) {
        array = (T[]) Array.newInstance(type, size);
        this.x = x;
    }

    public void forEach(Function<T> function) {
        for (T element : array) {
            x = function.perform(element, x);
        }
    }
}

class Compute {
    int factor;
    final long constant;

    public Compute(int factor, long constant) {
        this.factor = factor;
        this.constant = constant;
    }

    public long compute(long parameter, long x) {
        return x * factor + parameter + constant;
    }
}

public class Main {

    public static void main(String[] args) {
        List<Long> numbers = new ArrayList<Long>(50000000);
        for (int i = 0; i < 50000000; i++) {
            numbers.add(i * i + 5L);
        }

        long x = 234553523525L;

        long time = System.currentTimeMillis();
        for (int i = 0; i < numbers.size(); i++) {
            x += x * 7 + numbers.get(i) + 3;
        }
        System.out.println(System.currentTimeMillis() - time);
        System.out.println(x);
        x = 0;
        time = System.currentTimeMillis();
        for (long i : numbers) {
            x += x * 7 + i + 3;
        }
        System.out.println(System.currentTimeMillis() - time);
        System.out.println(x);
        x = 0;
        numbers = null;
        MyArray<Long> myArray = new MyArray<Long>(50000000, Long.class, 234553523525L);
        for (int i = 0; i < 50000000; i++) {
            myArray.array[i] = i * i + 3L;
        }
        time = System.currentTimeMillis();
        myArray.forEach(new Function<Long>() {

            public long perform(Long parameter, long x) {
                return x * 8 + parameter + 5L;
            }
        });
        System.out.println(System.currentTimeMillis() - time);
        System.out.println(myArray.x);
        myArray = null;
        myArray = new MyArray<Long>(50000000, Long.class, 234553523525L);
        for (int i = 0; i < 50000000; i++) {
            myArray.array[i] = i * i + 3L;
        }
        time = System.currentTimeMillis();
        myArray.forEach(new Function<Long>() {

            public long perform(Long parameter, long x) {
                return new Compute(8, 5).compute(parameter, x);
            }
        });
        System.out.println(System.currentTimeMillis() - time);
        System.out.println(myArray.x);
    }
}

Gives following output on my system:

224
-699150247503735895
221
-699150247503735895
220
-699150247503735895
219
-699150247503735895

I'm running Ubuntu 12.10 alpha with OracleJDK 1.7 update 6.

In general HotSpot optimizes a lot of indirections and simple reduntant operations, so in general you shouldn't worry about them unless there are a lot of them in seqence or they are heavily nested.

On the other hand, indexed get on LinkedList is much slower than calling next on iterator for LinkedList so you can avoid that performance hit while retaining readability when you use iterators (explicitly or implicitly in for-each loop).

Best way to check if a URL is valid

function is_url($uri){
    if(preg_match( '/^(http|https):\\/\\/[a-z0-9_]+([\\-\\.]{1}[a-z_0-9]+)*\\.[_a-z]{2,5}'.'((:[0-9]{1,5})?\\/.*)?$/i' ,$uri)){
      return $uri;
    }
    else{
        return false;
    }
}

Google Play Services Library update and missing symbol @integer/google_play_services_version

For everyone using Eclipse, this is how you should do it.

Eclipse -> import -> existing android code -> browse -> navigate to google-play-services_lib FOLDER (android-sdk/extras/google/google_play_services/libproject).

Then, on your project

control click -> properties -> android -> libraries, add -> select the project you just imported -> ok

Retrofit 2: Get JSON from Response body

I found that a combination of the other answers works:

interface ApiInterface {
    @GET("/someurl")
    Call<ResponseBody> getdata()
}

apiService.getdata().enqueue(object : Callback {
    override fun onResponse(call: Call, response: Response) {
        val rawJsonString = response.body()?.string()
    }
})

The important part are that the response type should be ResponseBody and use response.body()?.string() to get the raw string.

https://stackoverflow.com/a/33286112/860488

Trying to use INNER JOIN and GROUP BY SQL with SUM Function, Not Working

This should work.

SELECT a.[CUSTOMER ID], a.[NAME], SUM(b.[AMOUNT]) AS [TOTAL AMOUNT]
FROM RES_DATA a INNER JOIN INV_DATA b
ON a.[CUSTOMER ID]=b.[CUSTOMER ID]
GROUP BY a.[CUSTOMER ID], a.[NAME]

I tested it with SQL Fiddle against SQL Server 2008: http://sqlfiddle.com/#!3/1cad5/1

Basically what's happening here is that, because of the join, you are getting the same row on the "left" (i.e. from the RES_DATA table) for every row on the "right" (i.e. the INV_DATA table) that has the same [CUSTOMER ID] value. When you group by just the columns on the left side, and then do a sum of just the [AMOUNT] column from the right side, it keeps the one row intact from the left side, and sums up the matching values from the right side.

How can I get the error message for the mail() function?

Try this. If I got any error on any file then I got error mail on my email id. Create two files index.php and checkErrorEmail.php and uploaded them to your server. Then load index.php with your browser.

Index.php

<?php
    include('checkErrorEmail.php');
    include('dereporting.php');
    $temp;
    echo 'hi '.$temp;
?>

checkErrorEmail.php

<?php
  // Destinations
  define("ADMIN_EMAIL", "[email protected]");
  //define("LOG_FILE", "/my/home/errors.log");

  // Destination types
  define("DEST_EMAIL", "1");
  //define("DEST_LOGFILE", "3");

  /* Examples */

  // Send an e-mail to the administrator
  //error_log("Fix me!", DEST_EMAIL, ADMIN_EMAIL);

  // Write the error to our log file
  //error_log("Error", DEST_LOGFILE, LOG_FILE);

  /**
    * my_error_handler($errno, $errstr, $errfile, $errline)
    *
    * Author(s): thanosb, ddonahue
    * Date: May 11, 2008
    * 
    * custom error handler
    *
    * Parameters:
    *  $errno:   Error level
    *  $errstr:  Error message
    *  $errfile: File in which the error was raised
    *  $errline: Line at which the error occurred
    */

  function my_error_handler($errno, $errstr, $errfile, $errline)
  {  
  echo "<br><br><br><br>errno ".$errno.",<br>errstr ".$errstr.",<br>errfile ".$errfile.",<br>errline ".$errline;
      if($errno)
      {
              error_log("Error: $errstr \n error on line $errline in file $errfile \n", DEST_EMAIL, ADMIN_EMAIL);
      }
    /*switch ($errno) {
      case E_USER_ERROR:
        // Send an e-mail to the administrator
        error_log("Error: $errstr \n Fatal error on line $errline in file $errfile \n", DEST_EMAIL, ADMIN_EMAIL);

        // Write the error to our log file
        //error_log("Error: $errstr \n Fatal error on line $errline in file $errfile \n", DEST_LOGFILE, LOG_FILE);
        break;

      case E_USER_WARNING:
        // Write the error to our log file
        //error_log("Warning: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
        break;

      case E_USER_NOTICE:
        // Write the error to our log file
       // error_log("Notice: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
        break;

      default:
        // Write the error to our log file
        //error_log("Unknown error [#$errno]: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
        break;
    }*/

    // Don't execute PHP's internal error handler
    return TRUE;
  }


  // Use set_error_handler() to tell PHP to use our method
  $old_error_handler = set_error_handler("my_error_handler");


?>

Reading JSON POST using PHP

Hello this is a snippet from an old project of mine that uses curl to get ip information from some free ip databases services which reply in json format. I think it might help you.

$ip_srv = array("http://freegeoip.net/json/$this->ip","http://smart-ip.net/geoip-json/$this->ip");

getUserLocation($ip_srv);

Function:

function getUserLocation($services) {

        $ctx = stream_context_create(array('http' => array('timeout' => 15))); // 15 seconds timeout

        for ($i = 0; $i < count($services); $i++) {

            // Configuring curl options
            $options = array (
                CURLOPT_RETURNTRANSFER => true, // return web page
                //CURLOPT_HEADER => false, // don't return headers
                CURLOPT_HTTPHEADER => array('Content-type: application/json'),
                CURLOPT_FOLLOWLOCATION => true, // follow redirects
                CURLOPT_ENCODING => "", // handle compressed
                CURLOPT_USERAGENT => "test", // who am i
                CURLOPT_AUTOREFERER => true, // set referer on redirect
                CURLOPT_CONNECTTIMEOUT => 5, // timeout on connect
                CURLOPT_TIMEOUT => 5, // timeout on response
                CURLOPT_MAXREDIRS => 10 // stop after 10 redirects
            ); 

            // Initializing curl
            $ch = curl_init($services[$i]);
            curl_setopt_array ( $ch, $options );

            $content = curl_exec ( $ch );
            $err = curl_errno ( $ch );
            $errmsg = curl_error ( $ch );
            $header = curl_getinfo ( $ch );
            $httpCode = curl_getinfo ( $ch, CURLINFO_HTTP_CODE );

            curl_close ( $ch );

            //echo 'service: ' . $services[$i] . '</br>';
            //echo 'err: '.$err.'</br>';
            //echo 'errmsg: '.$errmsg.'</br>';
            //echo 'httpCode: '.$httpCode.'</br>';
            //print_r($header);
            //print_r(json_decode($content, true));

            if ($err == 0 && $httpCode == 200 && $header['download_content_length'] > 0) {

                return json_decode($content, true);

            } 

        }
    }

How can I convert an HTML element to a canvas element?

Building on top of the Mozdev post that natevw references I've started a small project to render HTML to canvas in Firefox, Chrome & Safari. So for example you can simply do:

rasterizeHTML.drawHTML('<span class="color: green">This is HTML</span>' 
                     + '<img src="local_img.png"/>', canvas);

Source code and a more extensive example is here.

Remove duplicates from dataframe, based on two columns A,B, keeping row with max value in another column C

I think groupby should work.

df.groupby(['A', 'B']).max()['C']

If you need a dataframe back you can chain the reset index call.

df.groupby(['A', 'B']).max()['C'].reset_index()

Adding css class through aspx code behind

If you're not using the id for anything other than code-behind reference (since .net mangles the ids), you could use a panel control and reference it in your codebehind:

<asp:panel runat="server" id="classMe"></asp:panel>

classMe.cssClass = "someClass"

Count cells that contain any text

If you have cells with something like ="" and don't want to count them, you have to subtract number of empty cells from total number of cell by formula like

=row(G101)-row(G4)+1-countblank(G4:G101)

In case of 2-dimensional array it would be

=(row(G101)-row(A4)+1)*(column(G101)-column(A4)+1)-countblank(A4:G101)

Tested at google docs.

How to convert JSON string into List of Java object?

I made a method to do this below called jsonArrayToObjectList. Its a handy static class that will take a filename and the file contains an array in JSON form.

 List<Items> items = jsonArrayToObjectList(
            "domain/ItemsArray.json",  Item.class);

    public static <T> List<T> jsonArrayToObjectList(String jsonFileName, Class<T> tClass) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        final File file = ResourceUtils.getFile("classpath:" + jsonFileName);
        CollectionType listType = mapper.getTypeFactory()
            .constructCollectionType(ArrayList.class, tClass);
        List<T> ts = mapper.readValue(file, listType);
        return ts;
    }

How to redirect in a servlet filter?

I'm trying to find a method to redirect my request from filter to login page

Don't

You just invoke

chain.doFilter(request, response);

from filter and the normal flow will go ahead.

I don't know how to redirect from servlet

You can use

response.sendRedirect(url);

to redirect from servlet

How to increase application heap size in Eclipse?

  1. Go to Eclipse Folder
  2. Find Eclipse Icon in Eclipse Folder
  3. Right Click on it you will get option "Show Package Content"
  4. Contents folder will open on screen
  5. If you are on Mac then you'll find "MacOS"
  6. Open MacOS folder you'll find eclipse.ini file
  7. Open it in word or any file editor for edit

    ...

    -XX:MaxPermSize=256m
    
    -Xms40m
    
    -Xmx512m
    

    ...

  8. Replace -Xmx512m to -Xmx1024m

  9. Save the file and restart your Eclipse
  10. Have a Nice time :)

How can I search an array in VB.NET?

Dim inputString As String = "ra"
Enumerable.Range(0, arr.Length).Where(Function(x) arr(x).ToLower().Contains(inputString.ToLower()))

get current date from [NSDate date] but set the time to 10:00 am

As with all date manipulation you have to use NSDateComponents and NSCalendar

NSDate *now = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier: NSCalendarIdentifierGregorian];
NSDateComponents *components = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:now];
[components setHour:10];
NSDate *today10am = [calendar dateFromComponents:components];

in iOS8 Apple introduced a convenience method that saves a few lines of code:

NSDate *d = [calendar dateBySettingHour:10 minute:0 second:0 ofDate:[NSDate date] options:0];

Swift:

let calendar: NSCalendar! = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)
let now: NSDate! = NSDate()

let date10h = calendar.dateBySettingHour(10, minute: 0, second: 0, ofDate: now, options: NSCalendarOptions.MatchFirst)!

Matplotlib connect scatterplot points with line - Python

For red lines an points

plt.plot(dates, values, '.r-') 

or for x markers and blue lines

plt.plot(dates, values, 'xb-')

Writing/outputting HTML strings unescaped

In ASP.NET MVC 3 You should do something like this:

// Say you have a bit of HTML like this in your controller:
ViewBag.Stuff = "<li>Menu</li>"
//  Then you can do this in your view:
@MvcHtmlString.Create(ViewBag.Stuff)

The proxy server received an invalid response from an upstream server

This is not mentioned in you post but I suspect you are initiating an SSL connection from the browser to Apache, where VirtualHosts are configured, and Apache does a revese proxy to your Tomcat.

There is a serious bug in (some versions ?) of IE that sends the 'wrong' host information in an SSL connection (see EDIT below) and confuses the Apache VirtualHosts. In short the server name presented is the one of the reverse DNS resolution of the IP, not the one in the URL.

The workaround is to have one IP address per SSL virtual hosts/server name. Is short, you must end up with something like

1 server name == 1 IP address == 1 certificate == 1 Apache Virtual Host

EDIT

Though the conclusion is correct, the identification of the problem is better described here http://en.wikipedia.org/wiki/Server_Name_Indication

JPA or JDBC, how are they different?

JDBC is the predecessor of JPA.

JDBC is a bridge between the Java world and the databases world. In JDBC you need to expose all dirty details needed for CRUD operations, such as table names, column names, while in JPA (which is using JDBC underneath), you also specify those details of database metadata, but with the use of Java annotations.

So JPA creates update queries for you and manages the entities that you looked up or created/updated (it does more as well).

If you want to do JPA without a Java EE container, then Spring and its libraries may be used with the very same Java annotations.

CSS text-decoration underline color

As far as I know it's not possible... but you can try something like this:

_x000D_
_x000D_
.underline _x000D_
{_x000D_
    color: blue;_x000D_
    border-bottom: 1px solid red;_x000D_
}
_x000D_
<div>_x000D_
    <span class="underline">hello world</span>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Jenkins restrict view of jobs per user

I use combination of several plugins - for the basic assignment of roles and permission I use Role Strategy Plugin.

When I need to split some role depending on parameters (e.g. everybody with job-runner is able to run jobs, but user only user UUU is allowed to run the deployment job to deploy on machine MMM), I use Python Plugin and define a python script as first build step and end with sys.exit(-1) when the job is forbidden to be run with the given combination of parameters.

Build User Vars Plugin provides me the information about the user executing the job as environment variables.

E.g:

import os
import sys

print os.environ["BUILD_USER"], "deploying to", os.environ["target_host"]

# only some users are allowed to deploy to servers "MMM"
mmm_users = ["UUU"]

if os.environ["target_host"] != "MMM" or os.environ["BUILD_USER"] in mmm_users:
    print "access granted"
else:
    print "access denied"
    sys.exit(-1)

Convert line endings

Some options:

Using tr

tr -d '\15\32' < windows.txt > unix.txt

OR

tr -d '\r' < windows.txt > unix.txt 

Using perl

perl -p -e 's/\r$//' < windows.txt > unix.txt

Using sed

sed 's/^M$//' windows.txt > unix.txt

OR

sed 's/\r$//' windows.txt > unix.txt

To obtain ^M, you have to type CTRL-V and then CTRL-M.

How to simulate POST request?

Dont forget to add user agent since some server will block request if there's no server agent..(you would get Forbidden resource response) example :

curl -X POST -A 'Mozilla/5.0 (X11; Linux x86_64; rv:30.0) Gecko/20100101 Firefox/30.0' -d "field=acaca&name=afadxx" https://example.com

Read binary file as string in Ruby

on os x these are the same for me... could this maybe be extra "\r" in windows?

in any case you may be better of with:

contents = File.read("e.tgz")
newFile = File.open("ee.tgz", "w")
newFile.write(contents)

ASP.Net 2012 Unobtrusive Validation with jQuery

All the validator error has been solved by this

 <appSettings>
<add key="ValidationSettings:UnobtrusiveValidationMode" value="None"/>

Error must be vanished enjoy....

Clear an input field with Reactjs?

Let me assume that you have done the 'this' binding of 'sendThru' function.

The below functions clears the input fields when the method is triggered.

sendThru() {
    this.inputTitle.value = "";
    this.inputEntry.value = "";
}

Refs can be written as inline function expression:

ref={el => this.inputTitle = el}

where el refers to the component.

When refs are written like above, React sees a different function object each time so on every update, ref will be called with null immediately before it's called with the component instance.

Read more about it here.

How to store Java Date to Mysql datetime with JPA

you will get 2011-07-18 + time format

long timeNow = Calendar.getInstance().getTimeInMillis();
java.sql.Timestamp ts = new java.sql.Timestamp(timeNow);
...
preparedStatement.setTimestamp(TIME_COL_INDEX, ts);

How can I get the full/absolute URL (with domain) in Django?

If you're using django REST framework, you can use the reverse function from rest_framework.reverse. This has the same behavior as django.core.urlresolvers.reverse, except that it uses a request parameter to build a full URL.

from rest_framework.reverse import reverse

# returns the full url
url = reverse('view_name', args=(obj.pk,), request=request)

# returns only the relative url
url = reverse('view_name', args=(obj.pk,))

Edited to mention availability only in REST framework

SSH -L connection successful, but localhost port forwarding not working "channel 3: open failed: connect failed: Connection refused"

I used to meet the similar problem because 'localhost' was not available on server when it restarted network service, e.g. 'ifdown -a' but followed by only 'ifup -eo1'. Besides server is not listening to the port, you can also check 'localhost' is available or not.

ps: Post it just hope someone who has the similar problem may benefit.

Understanding the grid classes ( col-sm-# and col-lg-# ) in Bootstrap 3

The best way to understand is to simply think from top to bottom ( Large Desktops to Mobile Phones)

Firstly, as B3 is mobile first so if you use xs then the columns will be same from Large desktops to xs ( i recommend using xs or sm as this will keep everything the way you want on every screen size )

Secondly if you want to give different width to columns on different devices or resolutions, than you can add multiple classes e.g

the above will change the width according to the screen resolutions, REMEMBER i am keeping the total columns in each class = 12

I hope my answer would help!

Showing the same file in both columns of a Sublime Text window

Inside sublime editor,Find the Tab named View,

View --> Layout --> "select your need"

How to install OpenSSL in windows 10?

You can install openssl using one single line if you have chocolatey installed

  1. open command in admin mode
  2. type choco install openssl

When & why to use delegates?

I've just go my head around these, and so I'll share an example as you already have descriptions but at the moment one advantage I see is to get around the Circular Reference style warnings where you can't have 2 projects referencing each other.

Let's assume an application downloads an XML, and then saves the XML to a database.

I have 2 projects here which build my solution: FTP and a SaveDatabase.

So, our application starts by looking for any downloads and downloading the file(s) then it calls the SaveDatabase project.

Now, our application needs to notify the FTP site when a file is saved to the database by uploading a file with Meta data (ignore why, it's a request from the owner of the FTP site). The issue is at what point and how? We need a new method called NotifyFtpComplete() but in which of our projects should it be saved too - FTP or SaveDatabase? Logically, the code should live in our FTP project. But, this would mean our NotifyFtpComplete will have to be triggered or, it will have to wait until the save is complete, and then query the database to ensure it is in there. What we need to do is tell our SaveDatabase project to call the NotifyFtpComplete() method direct but we can't; we'd get a ciruclar reference and the NotifyFtpComplete() is a private method. What a shame, this would have worked. Well, it can.

During our application's code, we would have passed parameters between methods, but what if one of those parameters was the NotifyFtpComplete method. Yup, we pass the method, with all of the code inside as well. This would mean we could execute the method at any point, from any project. Well, this is what the delegate is. This means, we can pass the NotifyFtpComplete() method as a parameter to our SaveDatabase() class. At the point it saves, it simply executes the delegate.

See if this crude example helps (pseudo code). We will also assume that the application starts with the Begin() method of the FTP class.

class FTP
{
    public void Begin()
    {
        string filePath = DownloadFileFromFtpAndReturnPathName();

        SaveDatabase sd = new SaveDatabase();
        sd.Begin(filePath, NotifyFtpComplete());
    }

    private void NotifyFtpComplete()
    {
        //Code to send file to FTP site
    }
}


class SaveDatabase
{
    private void Begin(string filePath, delegateType NotifyJobComplete())
    {
        SaveToTheDatabase(filePath);

        /* InvokeTheDelegate - 
         * here we can execute the NotifyJobComplete
         * method at our preferred moment in the application,
         * despite the method being private and belonging
         * to a different class.
         */
        NotifyJobComplete.Invoke();
    }
}

So, with that explained, we can do it for real now with this Console Application using C#

using System;

namespace ConsoleApplication1
{
    /* I've made this class private to demonstrate that 
    * the SaveToDatabase cannot have any knowledge of this Program class.
    */
    class Program
    {
        static void Main(string[] args)
        {
            //Note, this NotifyDelegate type is defined in the SaveToDatabase project
            NotifyDelegate nofityDelegate = new NotifyDelegate(NotifyIfComplete);

            SaveToDatabase sd = new SaveToDatabase();            
            sd.Start(nofityDelegate);
            Console.ReadKey();
        }

        /* this is the method which will be delegated -
         * the only thing it has in common with the NofityDelegate
         * is that it takes 0 parameters and that it returns void.
         * However, it is these 2 which are essential.
         * It is really important to notice that it writes
         * a variable which, due to no constructor,
         * has not yet been called (so _notice is not initialized yet).
         */ 
    private static void NotifyIfComplete()
    {
        Console.WriteLine(_notice);
    }

    private static string _notice = "Notified";
    }


    public class SaveToDatabase
    {
        public void Start(NotifyDelegate nd)
        {
            /* I shouldn't write to the console from here, 
             * just for demonstration purposes
             */
            Console.WriteLine("SaveToDatabase Complete");
            Console.WriteLine(" ");
            nd.Invoke();
        }
    }
    public delegate void NotifyDelegate();
}

I suggest you step through the code and see when _notice is called and when the method (delegate) is called as this, I hope, will make things very clear.

However, lastly, we can make it more useful by changing the delegate type to include a parameter.

using System.Text;

namespace ConsoleApplication1
{
    /* I've made this class private to demonstrate that the SaveToDatabase
     * cannot have any knowledge of this Program class.
     */
    class Program
    {
        static void Main(string[] args)
        {
            SaveToDatabase sd = new SaveToDatabase();
            /* Please note, that although NotifyIfComplete()
         * takes a string parameter, we do not declare it,
         * all we want to do is tell C# where the method is
         * so it can be referenced later,
         * we will pass the parameter later.
         */
            var notifyDelegateWithMessage = new NotifyDelegateWithMessage(NotifyIfComplete);

            sd.Start(notifyDelegateWithMessage );

            Console.ReadKey();
        }

        private static void NotifyIfComplete(string message)
        {
            Console.WriteLine(message);
        }
    }


    public class SaveToDatabase
    {
        public void Start(NotifyDelegateWithMessage nd)
        {
                        /* To simulate a saving fail or success, I'm just going
         * to check the current time (well, the seconds) and
         * store the value as variable.
         */
            string message = string.Empty;
            if (DateTime.Now.Second > 30)
                message = "Saved";
            else
                message = "Failed";

            //It is at this point we pass the parameter to our method.
            nd.Invoke(message);
        }
    }

    public delegate void NotifyDelegateWithMessage(string message);
}

How to increase font size in the Xcode editor?

I used cmd+ and it worked well to increase.. Same for decreasing cmq-

What's the difference between a 302 and a 307 redirect?

307 came about because user agents adopted as a de facto behaviour to take POST requests that receive a 302 response and send a GET request to the Location response header.

That is the incorrect behaviour — only a 303 should cause a POST to turn into a GET. User agents should (but don't) stick with the POST method when requesting the new URL if the original POST request returned a 302.

307 was introduced to allow servers to make it clear to the user agent that a method change should not be made by the client when following the Location response header.

How do I create ColorStateList programmatically?

Bouncing off the answer by Jonathan Ellis, in Kotlin you can define a helper function to make the code a bit more idiomatic and easier to read, so you can write this instead:

val colorList = colorStateListOf(
    intArrayOf(-android.R.attr.state_enabled) to Color.BLACK,
    intArrayOf(android.R.attr.state_enabled) to Color.RED,
)

colorStateListOf can be implemented like this:

fun colorStateListOf(vararg mapping: Pair<IntArray, Int>): ColorStateList {
    val (states, colors) = mapping.unzip()
    return ColorStateList(states.toTypedArray(), colors.toIntArray())
}

I also have:

fun colorStateListOf(@ColorInt color: Int): ColorStateList {
    return ColorStateList.valueOf(color)
}

So that I can call the same function name, no matter if it's a selector or single color.

What is the difference between a Shared Project and a Class Library in Visual Studio 2015?

From the book VS 2015 succintly

Shared Projects allows sharing code, assets, and resources across multiple project types. More specifically, the following project types can reference and consume shared projects:

  • Console, Windows Forms, and Windows Presentation Foundation.
  • Windows Store 8.1 apps and Windows Phone 8.1 apps.
  • Windows Phone 8.0/8.1 Silverlight apps.
  • Portable Class Libraries.

Note:- Both shared projects and portable class libraries (PCL) allow sharing code, XAML resources, and assets, but of course there are some differences that might be summarized as follows.

  • A shared project does not produce a reusable assembly, so it can only be consumed from within the solution.
  • A shared project has support for platform-specific code, because it supports environment variables such as WINDOWS_PHONE_APP and WINDOWS_APP that you can use to detect which platform your code is running on.
  • Finally, shared projects cannot have dependencies on third-party libraries.
  • By comparison, a PCL produces a reusable .dll library and can have dependencies on third-party libraries, but it does not support platform environment variables

jQuery DataTables: control table width

The issue is caused because dataTable must calculate its width - but when used inside a tab, it's not visible, hence can't calculate the widths. The solution is to call 'fnAdjustColumnSizing' when the tab shows.

Preamble

This example shows how DataTables with scrolling can be used together with jQuery UI tabs (or indeed any other method whereby the table is in a hidden (display:none) element when it is initialised). The reason this requires special consideration, is that when DataTables is initialised and it is in a hidden element, the browser doesn't have any measurements with which to give DataTables, and this will require in the misalignment of columns when scrolling is enabled.

The method to get around this is to call the fnAdjustColumnSizing API function. This function will calculate the column widths that are needed based on the current data and then redraw the table - which is exactly what is needed when the table becomes visible for the first time. For this we use the 'show' method provided by jQuery UI tables. We check to see if the DataTable has been created or not (note the extra selector for 'div.dataTables_scrollBody', this is added when the DataTable is initialised). If the table has been initialised, we re-size it. An optimisation could be added to re-size only of the first showing of the table.

Initialisation code

$(document).ready(function() {
    $("#tabs").tabs( {
        "show": function(event, ui) {
            var oTable = $('div.dataTables_scrollBody>table.display', ui.panel).dataTable();
            if ( oTable.length > 0 ) {
                oTable.fnAdjustColumnSizing();
            }
        }
    } );

    $('table.display').dataTable( {
        "sScrollY": "200px",
        "bScrollCollapse": true,
        "bPaginate": false,
        "bJQueryUI": true,
        "aoColumnDefs": [
            { "sWidth": "10%", "aTargets": [ -1 ] }
        ]
    } );
} );

See this for more info.

codes for ADD,EDIT,DELETE,SEARCH in vb2010

Have you googled about it - insert update delete access vb.net, there are lots of reference about this.

Insert Update Delete Navigation & Searching In Access Database Using VB.NET

  • Create Visual Basic 2010 Project: VB-Access
  • Assume that, we have a database file named data.mdb
  • Place the data.mdb file into ..\bin\Debug\ folder (Where the project executable file (.exe) is placed)

what could be the easier way to connect and manipulate the DB?
Use OleDBConnection class to make connection with DB

is it by using MS ACCESS 2003 or MS ACCESS 2007?
you can use any you want to use or your client will use on their machine.

it seems that you want to find some example of opereations fo the database. Here is an example of Access 2010 for your reference:

Example code snippet:

Imports System
Imports System.Data
Imports System.Data.OleDb

Public Class DBUtil

 Private connectionString As String

 Public Sub New()

  Dim con As New OleDb.OleDbConnection
  Dim dbProvider As String = "Provider=Microsoft.ace.oledb.12.0;"
  Dim dbSource = "Data Source=d:\DB\Database11.accdb"

  connectionString = dbProvider & dbSource

 End Sub

 Public Function GetCategories() As DataSet

  Dim query As String = "SELECT * FROM Categories"
  Dim cmd As New OleDbCommand(query)
  Return FillDataSet(cmd, "Categories")

 End Function

 Public SubUpdateCategories(ByVal name As String)
  Dim query As String = "update Categories set name = 'new2' where name = ?"
  Dim cmd As New OleDbCommand(query)
cmd.Parameters.AddWithValue("Name", name)
  Return FillDataSet(cmd, "Categories")

 End Sub

 Public Function GetItems() As DataSet

  Dim query As String = "SELECT * FROM Items"
  Dim cmd As New OleDbCommand(query)
  Return FillDataSet(cmd, "Items")

 End Function

 Public Function GetItems(ByVal categoryID As Integer) As DataSet

  'Create the command.
  Dim query As String = "SELECT * FROM Items WHERE Category_ID=?"
  Dim cmd As New OleDbCommand(query)
  cmd.Parameters.AddWithValue("category_ID", categoryID)

  'Fill the dataset.
  Return FillDataSet(cmd, "Items")

 End Function

 Public Sub AddCategory(ByVal name As String)

  Dim con As New OleDbConnection(connectionString)

  'Create the command.
  Dim insertSQL As String = "INSERT INTO Categories "
  insertSQL &= "VALUES(?)"
  Dim cmd As New OleDbCommand(insertSQL, con)
  cmd.Parameters.AddWithValue("Name", name)

  Try
   con.Open()
   cmd.ExecuteNonQuery()
  Finally
   con.Close()
  End Try

 End Sub

 Public Sub AddItem(ByVal title As String, ByVal description As String, _
    ByVal price As Decimal, ByVal categoryID As Integer)

  Dim con As New OleDbConnection(connectionString)

  'Create the command.
  Dim insertSQL As String = "INSERT INTO Items "
  insertSQL &= "(Title, Description, Price, Category_ID)"
  insertSQL &= "VALUES (?, ?, ?, ?)"
  Dim cmd As New OleDb.OleDbCommand(insertSQL, con)
  cmd.Parameters.AddWithValue("Title", title)
  cmd.Parameters.AddWithValue("Description", description)
  cmd.Parameters.AddWithValue("Price", price)
  cmd.Parameters.AddWithValue("CategoryID", categoryID)

  Try
   con.Open()
   cmd.ExecuteNonQuery()
  Finally
   con.Close()
  End Try

 End Sub

 Private Function FillDataSet(ByVal cmd As OleDbCommand, ByVal tableName As String) As DataSet

  Dim con As New OleDb.OleDbConnection
  Dim dbProvider As String = "Provider=Microsoft.ace.oledb.12.0;"
  Dim dbSource = "Data Source=D:\DB\Database11.accdb"

  connectionString = dbProvider & dbSource
  con.ConnectionString = connectionString
  cmd.Connection = con
  Dim adapter As New OleDbDataAdapter(cmd)
  Dim ds As New DataSet()

  Try
   con.Open()
   adapter.Fill(ds, tableName)
  Finally
   con.Close()
  End Try
  Return ds

 End Function

End Class

Refer these links:
Insert, Update, Delete & Search Values in MS Access 2003 with VB.NET 2005
INSERT, DELETE, UPDATE AND SELECT Data in MS-Access with VB 2008
How Add new record ,Update record,Delete Records using Vb.net Forms when Access as a back

How do I find out where login scripts live?

In addition from the command prompt run SET.

This displayed the "LOGONSERVER" value which indicates the specific domain controller you are using (there can be more than one).

Then you got to that server's NetBios Share \Servername\SYSVOL\domain.local\scripts.

How can I move a tag on a git branch to a different commit?

More precisely, you have to force the addition of the tag, then push with option --tags and -f:

git tag -f -a <tagname>
git push -f --tags

jQuery: Slide left and slide right

You can do this with the additional effects in jQuery UI: See here for details

Quick example:

$(this).hide("slide", { direction: "left" }, 1000);
$(this).show("slide", { direction: "left" }, 1000);

How to see an HTML page on Github as a normal rendered HTML page to see preview in browser, without downloading?

If you don't want to download an archive you can use GitHub Pages to render this.

  1. Fork the repository to your account.
  2. Clone it locally on your machine
  3. Create a gh-pages branch (if one already exists, remove it and create a new one based off master).
  4. Push the branch back to GitHub.
  5. View the pages at http://username.github.io/repo`

In code:

git clone [email protected]:username/repo.git
cd repo
git branch gh-pages
# Might need to do this first: git branch -D gh-pages
git push -u origin gh-pages # Push the new branch back to github
Go to http://username.github.io/repo

Moment.js transform to date object

I needed to have timezone information in my date string. I was originally using moment.tz(dateStr, 'America/New_York').toString(); but then I started getting errors about feeding that string back into moment.

I tried the moment.tz(dateStr, 'America/New_York').toDate(); but then I lost timezone information which I needed.

The only solution that returned a usable date string with timezone that could be fed back into moment was moment.tz(dateStr, 'America/New_York').format();

Bootstrap modal not displaying

I had my modal < div > inside my < li >.... not good.

Outside works fine :-)

<div class="modal fade" id="confirm-logout" tabindex="-1" role="dialog" aria-labelledby="logoutLabel" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                <h4 class="modal-title" id="myModalLabel">....</h4>
            </div>

            <div class="modal-body">
                <p>....</p>
            </div>

            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
                <a class="btn btn-danger btn-ok">OK</a>
            </div>
        </div>
    </div>
</div>
<li>
    .....
</li>

MSOnline can't be imported on PowerShell (Connect-MsolService error)

After reviewing Microsoft's TechNet article "Azure Active Directory Cmdlets" -> section "Install the Azure AD Module", it seems that this process has been drastically simplified, thankfully.

As of 2016/06/30, in order to successfully execute the PowerShell commands Import-Module MSOnline and Connect-MsolService, you will need to install the following applications (64-bit only):

  1. Applicable Operating Systems: Windows 7 to 10
    Name: "Microsoft Online Services Sign-in Assistant for IT Professionals RTW"
    Version: 7.250.4556.0 (latest)
    Installer URL: https://www.microsoft.com/en-us/download/details.aspx?id=41950
    Installer file name: msoidcli_64.msi
  2. Applicable Operating Systems: Windows 7 to 10
    Name: "Windows Azure Active Directory Module for Windows PowerShell"
    Version: Unknown but the latest installer file's SHA-256 hash is D077CF49077EE133523C1D3AE9A4BF437D220B16D651005BBC12F7BDAD1BF313
    Installer URL: https://technet.microsoft.com/en-us/library/dn975125.aspx
    Installer file name: AdministrationConfig-en.msi
  3. Applicable Operating Systems: Windows 7 only
    Name: "Windows PowerShell 3.0"
    Version: 3.0 (later versions will probably work too)
    Installer URL: https://www.microsoft.com/en-us/download/details.aspx?id=34595
    Installer file name: Windows6.1-KB2506143-x64.msu

 

enter image description here enter image description here enter image description here

Add custom message to thrown exception while maintaining stack trace in Java

Try:

throw new Exception("transction: " + transNbr, E); 

Android Stop Emulator from Command Line

I use this one-liner, broken into several lines for readability:

adb devices |
 perl -nle 'print $1 if /emulator-(\d+).device$/' |
 xargs -t -l1 -i bash -c "
   ( echo auth $(cat $HOME/.emulator_console_auth_token) ;
     echo kill ;
     yes ) |
   telnet localhost {}"

What are the differences between a superkey and a candidate key?

Super Key: A superkey is any set of attributes for which the values are guaranteed to be unique for all possible set of tuples in a table at all time.

Candidate Key: A candidate key is a 'minimal' super key meaning the smallest subset of superkey attribute which is unique.

How to copy a selection to the OS X clipboard

You can visually select text and type :w !pbcopy<CR>

Or you can include the below key mappings in your ~/.vimrc file. They cut/copy text in visual mode to the operating system's clipboard.

vmap <C-x> :!pbcopy<CR>  
vmap <C-c> :w !pbcopy<CR><CR> 

source: http://drydevelopment.com/blog/vim-pbcopy-on-os-x

How to name an object within a PowerPoint slide?

Select the Object -> Format -> Selection Pane -> Double click to change the name

enter image description here

How to get UTC value for SYSDATE on Oracle

Usually, I work with DATE columns, not the larger but more precise TIMESTAMP used by some answers.

The following will return the current UTC date as just that -- a DATE.

CAST(sys_extract_utc(SYSTIMESTAMP) AS DATE)

I often store dates like this, usually with the field name ending in _UTC to make it clear for the developer. This allows me to avoid the complexity of time zones until last-minute conversion by the user's client. Oracle can store time zone detail with some data types, but those types require more table space than DATE, and knowledge of the original time zone is not always required.

Android - get children inside a View?

If you not only want to get all direct children but all children's children and so on, you have to do it recursively:

private ArrayList<View> getAllChildren(View v) {

    if (!(v instanceof ViewGroup)) {
        ArrayList<View> viewArrayList = new ArrayList<View>();
        viewArrayList.add(v);
        return viewArrayList;
    }

    ArrayList<View> result = new ArrayList<View>();

    ViewGroup vg = (ViewGroup) v;
    for (int i = 0; i < vg.getChildCount(); i++) {

        View child = vg.getChildAt(i);

        ArrayList<View> viewArrayList = new ArrayList<View>();
        viewArrayList.add(v);
        viewArrayList.addAll(getAllChildren(child));

        result.addAll(viewArrayList);
    }
    return result;
}

To use the result you could do something like this:

    // check if a child is set to a specific String
    View myTopView;
    String toSearchFor = "Search me";
    boolean found = false;
    ArrayList<View> allViewsWithinMyTopView = getAllChildren(myTopView);
    for (View child : allViewsWithinMyTopView) {
        if (child instanceof TextView) {
            TextView childTextView = (TextView) child;
            if (TextUtils.equals(childTextView.getText().toString(), toSearchFor)) {
                found = true;
            }
        }
    }
    if (!found) {
        fail("Text '" + toSearchFor + "' not found within TopView");
    }

System has not been booted with systemd as init system (PID 1). Can't operate

This worked for me (using WSL)

sudo /etc/init.d/redis start

(for any other service, check the init.d folder for filenames)

How to add button tint programmatically

The way I managed to get mine to work was by using CompoundButtonCompat.setButtonTintList(button, colour).

To my understanding this works regardless of android version.

printf formatting (%d versus %u)

The difference is simple: they cause different warning messages to be emitted when compiling:

1156942.c:7:31: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int *’ [-Wformat=]
     printf("memory address = %d\n", &a); // prints "memory add=-12"
                               ^
1156942.c:8:31: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 2 has type ‘int *’ [-Wformat=]
     printf("memory address = %u\n", &a); // prints "memory add=65456"
                               ^

If you pass your pointer as a void* and use %p as the conversion specifier, then you get no error message:

#include <stdio.h>

int main()
{
    int a = 5;
    // check the memory address
    printf("memory address = %d\n", &a); /* wrong */
    printf("memory address = %u\n", &a); /* wrong */
    printf("memory address = %p\n", (void*)&a); /* right */
}

Creating a batch file, for simple javac and java command execution

you want these four lines of code in your Run.bat:

@echo off          //this makes it so you have an empty cmd window on startup
javac Main.java    //this compiles the .java into a .class
java Main          // this runs the .class file
pause              //this prevents the window from instantly closing after program end

How to check if a value exists in a dictionary (python)

In Python 3 you can use the values() function of the dictionary. It returns a view object of the values. This, in turn, can be passed to the iter function which returns an iterator object. The iterator can be checked using in, like this,

'one' in iter(d.values())

Or you can use the view object directly since it is similar to a list

'one' in d.values()

How can I sort a List alphabetically?

Assuming that those are Strings, use the convenient static method sort

 java.util.Collections.sort(listOfCountryNames)

How do I extract specific 'n' bits of a 32-bit unsigned integer in C?

If you want n bits specific then you could first create a bitmask and then AND it with your number to take the desired bits.

Simple function to create mask from bit a to bit b.

unsigned createMask(unsigned a, unsigned b)
{
   unsigned r = 0;
   for (unsigned i=a; i<=b; i++)
       r |= 1 << i;

   return r;
}

You should check that a<=b.

If you want bits 12 to 16 call the function and then simply & (logical AND) r with your number N

r = createMask(12,16);
unsigned result = r & N;

If you want you can shift the result. Hope this helps

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

rename_axis + reset_index

You can first rename your index to a desired label, then elevate to a series:

df = df.rename_axis('index1').reset_index()

print(df)

   index1         gi  ptt_loc
0       0  384444683      593
1       1  384444684      594
2       2  384444686      596

This works also for MultiIndex dataframes:

print(df)
#                        val
# tick       tag obs        
# 2016-02-26 C   2    0.0139
# 2016-02-27 A   2    0.5577
# 2016-02-28 C   6    0.0303

df = df.rename_axis(['index1', 'index2', 'index3']).reset_index()

print(df)

       index1 index2  index3     val
0  2016-02-26      C       2  0.0139
1  2016-02-27      A       2  0.5577
2  2016-02-28      C       6  0.0303

How to tag an older commit in Git?

This is an old question, and the answers already given all work, but there's also a new option which can be considered.

If you're using SourceTree to manage your git repositories, you can right-click on any commit and add a tag to it. With another mouseclick you can also send the tag straight to the branch on origin.

How / can I display a console window in Intellij IDEA?

  1. Press the left corner button
  2. Choose debug
  3. Click console

enter image description here

enter image description here

How to format code in Xcode?

Select first the text you want to format and then press Ctrl+I.

Use Cmd+A first if you wish to format all text in the selected file.

Note: this procedure only re-indents the lines, it does not do any advanced formatting.


In XCode 12 beta:

The new key binding to re-indent is control+I.

Subdomain on different host

You just need to add an "A" record in the DNS manager on Godaddy. In that "A" record put your IP from dreamhost.

I know this works since I'm doing the very same thing.

Remove excess whitespace from within a string

$str = str_replace(' ','',$str);

Or, replace with underscore, & nbsp; etc etc.

Display image at 50% of its "native" size

Maybe one of the easiest solutions would be to use the x descriptor of the srcset attribute as such:

_x000D_
_x000D_
<!-- Original image -->
<img src="https://fr.wikipedia.org/static/images/mobile/copyright/wikipedia.png" />

<!-- With a 80% size reduction (1/0.8=1.25) -->
<img srcset="https://fr.wikipedia.org/static/images/mobile/copyright/wikipedia.png 1.25x" />

<!-- With a 50% size reduction (1/0.5=2) -->
<img srcset="https://fr.wikipedia.org/static/images/mobile/copyright/wikipedia.png 2x" />
_x000D_
_x000D_
_x000D_

Currently supported by all browsers except IE. (caniuse)

MDN documentation

How to use Visual Studio Code as Default Editor for Git

Good news! At the time of writing, this feature has already been implemented in the 0.10.12-insiders release and carried out through 0.10.14-insiders. Hence we are going to have it in the upcoming version 1.0 Release of VS Code.

Implementation Ref: Implement -w/--wait command line arg

What are the "standard unambiguous date" formats for string-to-date conversion in R?

Converting the date without specifying the current format can bring this error to you easily.

Here is an example:

sdate <- "2015.10.10"

Convert without specifying the Format:

date <- as.Date(sdate4) # ==> This will generate the same error"""Error in charToDate(x): character string is not in a standard unambiguous format""".

Convert with specified Format:

date <- as.Date(sdate4, format = "%Y.%m.%d") # ==> Error Free Date Conversion.

How do I pass a unique_ptr argument to a constructor or a function?

Here are the possible ways to take a unique pointer as an argument, as well as their associated meaning.

(A) By Value

Base(std::unique_ptr<Base> n)
  : next(std::move(n)) {}

In order for the user to call this, they must do one of the following:

Base newBase(std::move(nextBase));
Base fromTemp(std::unique_ptr<Base>(new Base(...));

To take a unique pointer by value means that you are transferring ownership of the pointer to the function/object/etc in question. After newBase is constructed, nextBase is guaranteed to be empty. You don't own the object, and you don't even have a pointer to it anymore. It's gone.

This is ensured because we take the parameter by value. std::move doesn't actually move anything; it's just a fancy cast. std::move(nextBase) returns a Base&& that is an r-value reference to nextBase. That's all it does.

Because Base::Base(std::unique_ptr<Base> n) takes its argument by value rather than by r-value reference, C++ will automatically construct a temporary for us. It creates a std::unique_ptr<Base> from the Base&& that we gave the function via std::move(nextBase). It is the construction of this temporary that actually moves the value from nextBase into the function argument n.

(B) By non-const l-value reference

Base(std::unique_ptr<Base> &n)
  : next(std::move(n)) {}

This has to be called on an actual l-value (a named variable). It cannot be called with a temporary like this:

Base newBase(std::unique_ptr<Base>(new Base)); //Illegal in this case.

The meaning of this is the same as the meaning of any other use of non-const references: the function may or may not claim ownership of the pointer. Given this code:

Base newBase(nextBase);

There is no guarantee that nextBase is empty. It may be empty; it may not. It really depends on what Base::Base(std::unique_ptr<Base> &n) wants to do. Because of that, it's not very evident just from the function signature what's going to happen; you have to read the implementation (or associated documentation).

Because of that, I wouldn't suggest this as an interface.

(C) By const l-value reference

Base(std::unique_ptr<Base> const &n);

I don't show an implementation, because you cannot move from a const&. By passing a const&, you are saying that the function can access the Base via the pointer, but it cannot store it anywhere. It cannot claim ownership of it.

This can be useful. Not necessarily for your specific case, but it's always good to be able to hand someone a pointer and know that they cannot (without breaking rules of C++, like no casting away const) claim ownership of it. They can't store it. They can pass it to others, but those others have to abide by the same rules.

(D) By r-value reference

Base(std::unique_ptr<Base> &&n)
  : next(std::move(n)) {}

This is more or less identical to the "by non-const l-value reference" case. The differences are two things.

  1. You can pass a temporary:

    Base newBase(std::unique_ptr<Base>(new Base)); //legal now..
    
  2. You must use std::move when passing non-temporary arguments.

The latter is really the problem. If you see this line:

Base newBase(std::move(nextBase));

You have a reasonable expectation that, after this line completes, nextBase should be empty. It should have been moved from. After all, you have that std::move sitting there, telling you that movement has occurred.

The problem is that it hasn't. It is not guaranteed to have been moved from. It may have been moved from, but you will only know by looking at the source code. You cannot tell just from the function signature.

Recommendations

  • (A) By Value: If you mean for a function to claim ownership of a unique_ptr, take it by value.
  • (C) By const l-value reference: If you mean for a function to simply use the unique_ptr for the duration of that function's execution, take it by const&. Alternatively, pass a & or const& to the actual type pointed to, rather than using a unique_ptr.
  • (D) By r-value reference: If a function may or may not claim ownership (depending on internal code paths), then take it by &&. But I strongly advise against doing this whenever possible.

How to manipulate unique_ptr

You cannot copy a unique_ptr. You can only move it. The proper way to do this is with the std::move standard library function.

If you take a unique_ptr by value, you can move from it freely. But movement doesn't actually happen because of std::move. Take the following statement:

std::unique_ptr<Base> newPtr(std::move(oldPtr));

This is really two statements:

std::unique_ptr<Base> &&temporary = std::move(oldPtr);
std::unique_ptr<Base> newPtr(temporary);

(note: The above code does not technically compile, since non-temporary r-value references are not actually r-values. It is here for demo purposes only).

The temporary is just an r-value reference to oldPtr. It is in the constructor of newPtr where the movement happens. unique_ptr's move constructor (a constructor that takes a && to itself) is what does the actual movement.

If you have a unique_ptr value and you want to store it somewhere, you must use std::move to do the storage.

Check if element is visible in DOM

I've got a more performant solution compared to AlexZ's getComputedStyle() solution when one has position 'fixed' elements, if one is willing to ignore some edge cases (check comments):

function isVisible(el) {
    /* offsetParent would be null if display 'none' is set.
       However Chrome, IE and MS Edge returns offsetParent as null for elements
       with CSS position 'fixed'. So check whether the dimensions are zero.

       This check would be inaccurate if position is 'fixed' AND dimensions were
       intentionally set to zero. But..it is good enough for most cases.*/
    if (!el.offsetParent && el.offsetWidth === 0 && el.offsetHeight === 0) {
        return false;
    }
    return true;
}

Side note: Strictly speaking, "visibility" needs to be defined first. In my case, I am considering an element visible as long as I can run all DOM methods/properties on it without problems (even if opacity is 0 or CSS visibility property is 'hidden' etc).

How to make div occupy remaining height?

Demo

One way is to set the the div to position:absolute and give it a top of 50px and bottom of 0px;

#div2
{
    position:absolute;
    bottom:0px;
    top:50px
}

Find object in list that has attribute equal to some value (that meets any condition)

next((x for x in test_list if x.value == value), None)

This gets the first item from the list that matches the condition, and returns None if no item matches. It's my preferred single-expression form.

However,

for x in test_list:
    if x.value == value:
        print("i found it!")
        break

The naive loop-break version, is perfectly Pythonic -- it's concise, clear, and efficient. To make it match the behavior of the one-liner:

for x in test_list:
    if x.value == value:
        print("i found it!")
        break
else:
    x = None

This will assign None to x if you don't break out of the loop.

Use jQuery to change an HTML tag?

I noticed that the first answer wasn't quite what I needed, so I made a couple of modifications and figured I'd post it back here.

Improved replaceTag(<tagName>)

replaceTag(<tagName>, [withDataAndEvents], [withDataAndEvents])

Arguments:

  • tagName: String
    • The tag name e.g. "div", "span", etc.
  • withDataAndEvents: Boolean
    • "A Boolean indicating whether event handlers should be copied along with the elements. As of jQuery 1.4, element data will be copied as well." info
  • deepWithDataAndEvents: Boolean,
    • A Boolean indicating whether event handlers and data for all children of the cloned element should be copied. By default its value matches the first argument's value (which defaults to false)." info

Returns:

A newly created jQuery element

Okay, I know there are a few answers here now, but I took it upon myself to write this again.

Here we can replace the tag in the same way we use cloning. We are following the same syntax as .clone() with the withDataAndEvents and deepWithDataAndEvents which copy the child nodes' data and events if used.

Example:

$tableRow.find("td").each(function() {
  $(this).clone().replaceTag("li").appendTo("ul#table-row-as-list");
});

Source:

$.extend({
    replaceTag: function (element, tagName, withDataAndEvents, deepWithDataAndEvents) {
        var newTag = $("<" + tagName + ">")[0];
        // From [Stackoverflow: Copy all Attributes](http://stackoverflow.com/a/6753486/2096729)
        $.each(element.attributes, function() {
            newTag.setAttribute(this.name, this.value);
        });
        $(element).children().clone(withDataAndEvents, deepWithDataAndEvents).appendTo(newTag);
        return newTag;
    }
})
$.fn.extend({
    replaceTag: function (tagName, withDataAndEvents, deepWithDataAndEvents) {
        // Use map to reconstruct the selector with newly created elements
        return this.map(function() {
            return jQuery.replaceTag(this, tagName, withDataAndEvents, deepWithDataAndEvents);
        })
    }
})

Note that this does not replace the selected element, it returns the newly created one.

Difference between <? super T> and <? extends T> in Java

You can go through all the answers above to understand why the .add() is restricted to '<?>', '<? extends>', and partly to '<? super>'.

But here's the conclusion of it all if you want to remember it, and dont want to go exploring the answer every time:

List<? extends A> means this will accept any List of A and subclass of A. But you cannot add anything to this list. Not even objects of type A.

List<? super A> means this will accept any list of A and superclass of A. You can add objects of type A and its subclasses.

How can I tell when a MySQL table was last updated?

i made a column by name : update-at in phpMyAdmin and got the current time from Date() method in my code (nodejs) . with every change in table this column hold the time of changes.

Has an event handler already been added?

If this is the only handler, you can check to see if the event is null, if it isn't, the handler has been added.

I think you can safely call -= on the event with your handler even if it's not added (if not, you could catch it) -- to make sure it isn't in there before adding.

base64 encode in MySQL

For those interested, these are the only alternatives so far:

1) Using these Functions:

http://wi-fizzle.com/downloads/base64.sql

2) If you already have the sys_eval UDF, (Linux) you can do this:

sys_eval(CONCAT("echo '",myField,"' | base64"));

The first method is known to be slow. The problem with the second one, is that the encoding is actually happening "outside" MySQL, which can have encoding problems (besides the security risks that you are adding with sys_* functions).

Unfortunately there is no UDF compiled version (which should be faster) nor a native support in MySQL (Posgresql supports it!).

It seems that the MySQL development team are not interested in implement it as this function already exists in other languages, which seems pretty silly to me.

How to select an item in a ListView programmatically?

if (listView1.Items.Count > 0)
{
    listView1.Items[0].Selected = true;
    listView1.Select();
}

list items do not appear selected unless the control has the focus (or you set the HideSelection property to false)

How to run a command in the background on Windows?

I'm assuming what you want to do is run a command without an interface (possibly automatically?). On windows there are a number of options for what you are looking for:

  • Best: write your program as a windows service. These will start when no one logs into the server. They let you select the user account (which can be different than your own) and they will restart if they fail. These run all the time so you can automate tasks at specific times or on a regular schedule from within them. For more information on how to write a windows service you can read a tutorial online such as (http://msdn.microsoft.com/en-us/library/zt39148a(v=vs.110).aspx).

  • Better: Start the command and hide the window. Assuming the command is a DOS command you can use a VB or C# script for this. See here for more information. An example is:

    Set objShell = WScript.CreateObject("WScript.Shell")
    objShell.Run("C:\yourbatch.bat"), 0, True
    

    You are still going to have to start the command manually or write a task to start the command. This is one of the biggest down falls of this strategy.

  • Worst: Start the command using the startup folder. This runs when a user logs into the computer

Hope that helps some!

How to get the list of properties of a class?

I am also facing this kind of requirement.

From this discussion I got another Idea,

Obj.GetType().GetProperties()[0].Name

This is also showing the property name.

Obj.GetType().GetProperties().Count();

this showing number of properties.

Thanks to all. This is nice discussion.

Throw away local commits in Git

Delete the most recent commit:

git reset --hard HEAD~1

Delete the most recent commit, without destroying the work you've done:

git reset --soft HEAD~1

How do I check if a column is empty or null in MySQL?

In my case, space was entered in the column during the data import and though it looked like an empty column its length was 1. So first of all I checked the length of the empty looking column using length(column) then based on this we can write search query

SELECT * FROM TABLE WHERE LENGHT(COLUMN)= 0;

JUnit: how to avoid "no runnable methods" in test utils classes

Assuming you're in control of the pattern used to find test classes, I'd suggest changing it to match *Test rather than *Test*. That way TestHelper won't get matched, but FooTest will.

How do I strip all spaces out of a string in PHP?

If you want to remove all whitespace:

$str = preg_replace('/\s+/', '', $str);

See the 5th example on the preg_replace documentation. (Note I originally copied that here.)

Edit: commenters pointed out, and are correct, that str_replace is better than preg_replace if you really just want to remove the space character. The reason to use preg_replace would be to remove all whitespace (including tabs, etc.).

JavaScript sleep/wait before continuing

JS does not have a sleep function, it has setTimeout() or setInterval() functions.

If you can move the code that you need to run after the pause into the setTimeout() callback, you can do something like this:

//code before the pause
setTimeout(function(){
    //do what you need here
}, 2000);

see example here : http://jsfiddle.net/9LZQp/

This won't halt the execution of your script, but due to the fact that setTimeout() is an asynchronous function, this code

console.log("HELLO");
setTimeout(function(){
    console.log("THIS IS");
}, 2000);
console.log("DOG");

will print this in the console:

HELLO
DOG
THIS IS

(note that DOG is printed before THIS IS)


You can use the following code to simulate a sleep for short periods of time:

function sleep(milliseconds) {
  var start = new Date().getTime();
  for (var i = 0; i < 1e7; i++) {
    if ((new Date().getTime() - start) > milliseconds){
      break;
    }
  }
}

now, if you want to sleep for 1 second, just use:

sleep(1000);

example: http://jsfiddle.net/HrJku/1/

please note that this code will keep your script busy for n milliseconds. This will not only stop execution of Javascript on your page, but depending on the browser implementation, may possibly make the page completely unresponsive, and possibly make the entire browser unresponsive. In other words this is almost always the wrong thing to do.

How do you modify a CSS style in the code behind file for divs in ASP.NET?

It's an HtmlGenericControl so not sure what the recommended way to do this is, so you could also do:

testSpace.Attributes.Add("style", "text-align: center;");

or

testSpace.Attributes.Add("class", "centerIt");

or

testSpace.Attributes["style"] = "text-align: center;";

or

testSpace.Attributes["class"] = "centerIt";

Writing JSON object to a JSON file with fs.writeFileSync

Here's a variation, using the version of fs that uses promises:

const fs = require('fs');

await fs.promises.writeFile('../data/phraseFreqs.json', JSON.stringify(output)); // UTF-8 is default

How to check which version of Keras is installed?

The simplest way is using pip command:

pip list | grep Keras

difference between css height : 100% vs height : auto

The default is height: auto in browser, but height: X% Defines the height in percentage of the containing block.

How to set lifetime of session

Prior to PHP 7, the session_start() function did not directly accept any configuration options. Now you can do it this way

<?php
// This sends a persistent cookie that lasts a day.
session_start([
    'cookie_lifetime' => 86400,
]);
?>

Reference: https://php.net/manual/en/function.session-start.php#example-5976

How do I output text without a newline in PowerShell?

There seems to be no way to do this in PowerShell. All of the previous answers are not correct, because they do not behave the way Write-Output behaves but more like Write-Host which doesn't have this problem anyway.

The closes solution seems to use Write-Host with the -NoNewLine parameter. You can not pipe this which is a problem generally, but there is a way to override this function as described in Write-Host => Export to a file, so you can easily make it accept the parameter for an output file. This is still far from a good solution. With Start-Transcript this is more usable, but that cmdlet has problems with native applications.

Write-Outputsimply can't do what you need in a general context.

Foreign Key to multiple tables

You have a few options, all varying in "correctness" and ease of use. As always, the right design depends on your needs.

  • You could simply create two columns in Ticket, OwnedByUserId and OwnedByGroupId, and have nullable Foreign Keys to each table.

  • You could create M:M reference tables enabling both ticket:user and ticket:group relationships. Perhaps in future you will want to allow a single ticket to be owned by multiple users or groups? This design does not enforce that a ticket must be owned by a single entity only.

  • You could create a default group for every user and have tickets simply owned by either a true Group or a User's default Group.

  • Or (my choice) model an entity that acts as a base for both Users and Groups, and have tickets owned by that entity.

Heres a rough example using your posted schema:

create table dbo.PartyType
(   
    PartyTypeId tinyint primary key,
    PartyTypeName varchar(10)
)

insert into dbo.PartyType
    values(1, 'User'), (2, 'Group');


create table dbo.Party
(
    PartyId int identity(1,1) primary key,
    PartyTypeId tinyint references dbo.PartyType(PartyTypeId),
    unique (PartyId, PartyTypeId)
)

CREATE TABLE dbo.[Group]
(
    ID int primary key,
    Name varchar(50) NOT NULL,
    PartyTypeId as cast(2 as tinyint) persisted,
    foreign key (ID, PartyTypeId) references Party(PartyId, PartyTypeID)
)  

CREATE TABLE dbo.[User]
(
    ID int primary key,
    Name varchar(50) NOT NULL,
    PartyTypeId as cast(1 as tinyint) persisted,
    foreign key (ID, PartyTypeId) references Party(PartyID, PartyTypeID)
)

CREATE TABLE dbo.Ticket
(
    ID int primary key,
    [Owner] int NOT NULL references dbo.Party(PartyId),
    [Subject] varchar(50) NULL
)

How to compare strings

You need to use strcmp.

if (strcmp(string,"add") == 0){
    print("success!");
}

How to store Configuration file and read it using React

You can use the dotenv package no matter what setup you use. It allows you to create a .env in your project root and specify your keys like so

REACT_APP_SERVER_PORT=8000

In your applications entry file your just call dotenv(); before accessing the keys like so

process.env.REACT_APP_SERVER_PORT

Can a WSDL indicate the SOAP version (1.1 or 1.2) of the web service?

Yes you can usually see what SOAP version is supported based on the WSDL.

Take a look at Demo web service WSDL. It has a reference to the soap12 namespace indicating it supports SOAP 1.2. If that was absent then you'd probably be safe assuming the service only supported SOAP 1.1.

Converting strings to floats in a DataFrame

df['MyColumnName'] = df['MyColumnName'].astype('float64') 

Comparing arrays for equality in C++

Since nobody mentioned it yet, you can compare arrays with the std::equal algorithm:

int iar1[] = {1,2,3,4,5};
int iar2[] = {1,2,3,4,5};

if (std::equal(std::begin(iar1), std::end(iar1), std::begin(iar2)))
    cout << "Arrays are equal.";
else
    cout << "Arrays are not equal.";

You need to include <algorithm> and <iterator>. If you don't use C++11 yet, you can write:

if (std::equal(iar1, iar1 + sizeof iar1 / sizeof *iar1, iar2))

How to convert ZonedDateTime to Date?

The accepted answer did not work for me. The Date returned is always the local Date and not the Date for the original Time Zone. I live in UTC+2.

//This did not work for me
Date.from(java.time.ZonedDateTime.now().toInstant()); 

I have come up with two alternative ways to get the correct Date from a ZonedDateTime.

Say you have this ZonedDateTime for Hawaii

LocalDateTime ldt = LocalDateTime.now();
ZonedDateTime zdt = ldt.atZone(ZoneId.of("US/Hawaii"); // UTC-10

or for UTC as asked originally

Instant zulu = Instant.now(); // GMT, UTC+0
ZonedDateTime zdt = zulu.atZone(ZoneId.of("UTC"));

Alternative 1

We can use java.sql.Timestamp. It is simple but it will probably also make a dent in your programming integrity

Date date1 = Timestamp.valueOf(zdt.toLocalDateTime());

Alternative 2

We create the Date from millis (answered here earlier). Note that local ZoneOffset is a must.

ZoneOffset localOffset = ZoneOffset.systemDefault().getRules().getOffset(LocalDateTime.now());
long zonedMillis = 1000L * zdt.toLocalDateTime().toEpochSecond(localOffset) + zdt.toLocalDateTime().getNano() / 1000000L;
Date date2 = new Date(zonedMillis);

How to display the function, procedure, triggers source code in postgresql?

For function:

you can query the pg_proc view , just as the following

select proname,prosrc from pg_proc where proname= your_function_name; 

Another way is that just execute the commont \df and \ef which can list the functions.

skytf=> \df           
                                             List of functions
 Schema |         Name         | Result data type |              Argument data types               |  Type  
--------+----------------------+------------------+------------------------------------------------+--------
 public | pg_buffercache_pages | SETOF record     |                                                | normal


skytf=> \ef  pg_buffercache_pages

It will show the source code of the function.

For triggers:

I dont't know if there is a direct way to get the source code. Just know the following way, may be it will help you!

  • step 1 : Get the table oid of the trigger:
    skytf=> select tgrelid from pg_trigger  where tgname='insert_tbl_tmp_trigger';
      tgrelid
    ---------
       26599
    (1 row)
  • step 2: Get the table name of the above oid !
    skytf=> select oid,relname  from pg_class where oid=26599;
      oid  |           relname           
    -------+-----------------------------
     26599 | tbl_tmp
    (1 row)
  • step 3: list the table information
    skytf=> \d tbl_tmp

It will show you the details of the trigger of the table . Usually a trigger uses a function. So you can get the source code of the trigger function just as the above that I pointed out !

How to convert an image to base64 encoding?

Here is the code for upload to encode and save it to the MySQL

if (!isset($_GET["getfile"])) {
    if ($_FILES["file"]["error"] > 0) {
        echo "Error: " . $_FILES["file"]["error"] . "<br>";
    } else {
        move_uploaded_file($_FILES["file"]["tmp_name"], $_FILES["file"]["name"]);

        $bin_string = file_get_contents($_FILES["file"]["name"]);
        $hex_string = base64_encode($bin_string);
        $mysqli = mysqli_init();

        if (!$mysqli->real_connect('localhost', 'root', '', 'arihant')) {
            die('Connect Error (' . mysqli_connect_errno() . ') ' . mysqli_connect_error());
        }

        $mysqli->query("INSERT INTO upload(image) VALUES ('" . $hex_string . "')");
    }
}

For showing the image use this

echo "<img src='data:image/jpeg;base64, $image' width=300>";

What is <scope> under <dependency> in pom.xml for?

added good images with explain scopes

enter image description here

enter image description here

Node update a specific package

Always you can do it manually. Those are the steps:

  • Go to the NPM package page, and search for the GitHub link.
  • Now download the latest version using GitHub download link, or by clonning. git clone github_url
  • Copy the package to your node_modules folder for e.g. node_modules/browser-sync

Now it should work for you. To be sure it will not break in the future when you do npm i, continue the upcoming two steps:

  • Check the version of the new package by reading the package.json file in it's folder.
  • Open your project package.json and set the same version for where it's appear in the dependencies part of your package.json

While it's not recommened to do it manually. Sometimes it's good to understand how things are working under the hood, to be able to fix things. I found myself doing it from time to time.

MySQL Query GROUP BY day / month / year

If you want to group by date in MySQL then use the code below:

 SELECT COUNT(id)
 FROM stats
 GROUP BY DAYOFMONTH(record_date)

Hope this saves some time for the ones who are going to find this thread.

UITableView Separator line

You can add a UIImageView that is, for example, 1 point high and as wide as the cell's frame, and then set its origin to the bottom left corner of the cell.

How to fix: Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list

To solve the issue try to repair the .net framework 4 and then run the command

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

enter image description here

How to retrieve all keys (or values) from a std::map and put them into a vector?

Your solution is fine but you can use an iterator to do it:

std::map<int, int> m;
m.insert(std::pair<int, int>(3, 4));
m.insert(std::pair<int, int>(5, 6));
for(std::map<int, int>::const_iterator it = m.begin(); it != m.end(); it++)
{
    int key = it->first;
    int value = it->second;
    //Do something
}

Overloading operators in typedef structs (c++)

  1. bool operator==(pos a) const{ - this method doesn't change object's elements.
  2. bool operator==(pos a) { - it may change object's elements.

Phone validation regex

  ^[0-9\-\+]{9,15}$ 

would match 0+0+0+0+0+0, or 000000000, etc.

  (\-?[0-9]){7}

would match a specific number of digits with optional hyphens in any position among them.

What is this +077 format supposed to be?

It's not a valid format. No country codes begin with 0.

The digits after the + should usually be a country code, 1 to 3 digits long.

Allowing for "+" then country code CC, then optional hyphen, then "0" plus two digits, then hyphens and digits for next seven digits, try:

  ^\+CC\-?0[1-9][0-9](\-?[0-9]){7}$

Oh, and {3,3} is redundant, simplifes to {3}.

Fixed header, footer with scrollable content

As of 2013: This would be my approach. jsFiddle:


HTML

<header class="container global-header">
    <h1>Header (fixed)</h1>
</header>

<div class="container main-content">
    <div class="inner-w">
        <h1>Main Content</h1>
    </div><!-- .inner-w -->
</div> <!-- .main-content -->

<footer class="container global-footer">
    <h3>Footer (fixed)</h3>
</footer>


SCSS

// User reset

* { // creates a natural box model layout
    -moz-box-sizing: border-box; 
    -webkit-box-sizing: border-box; 
    box-sizing: border-box; 
} // asume normalize.css


// structure

.container {
    position: relative;
    width: 100%;
    float: left;
    padding: 1em;
}


// type

body {
    font-family: arial;   
}

.main-content {
    h1 {
        font-size: 2em;
        font-weight: bold;
        margin-bottom: .2em;
    }
} // .main-content


// style

    // variables
    $global-header-height: 8em;
    $global-footer-height: 6em;

.global-header {
    position: fixed;
    top: 0; left: 0;
    background-color: gray;
    height: $global-header-height;
}

.main-content {
    background-color: orange;
    margin-top: $global-header-height;
    margin-bottom: $global-footer-height;
    z-index: -1; // so header will be on top
    min-height: 50em; // to make it long so you can see the scrolling
}

.global-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    height: $global-footer-height;
    background-color: gray;
}

How do I write a compareTo method which compares objects?

If you using compare To method of the Comparable interface in any class. This can be used to arrange the string in Lexicographically.

public class Student() implements Comparable<Student>{

public int compareTo(Object obj){
if(this==obj){
    return 0;
}
if(obj!=null){
    String objName = ((Student)obj).getName();
    return this.name.comapreTo.(objName);
}
}

Create two-dimensional arrays and access sub-arrays in Ruby

You didn't state your actual goal, but maybe this can help:

require 'matrix'  # bundled with Ruby
m = Matrix[
 [1, 2, 3],
 [4, 5, 6]
]

m.column(0) # ==> Vector[1, 4]

(and Vectors acts like arrays)

or, using a similar notation as you desire:

m.minor(0..1, 2..2) # => Matrix[[3], [6]]

Add a column to a table, if it does not already exist

IF NOT EXISTS (SELECT 1  FROM SYS.COLUMNS WHERE  
OBJECT_ID = OBJECT_ID(N'[dbo].[Person]') AND name = 'DateOfBirth')
BEGIN
ALTER TABLE [dbo].[Person] ADD DateOfBirth DATETIME
END

Python error: AttributeError: 'module' object has no attribute

My solution is put those imports in __init__.py of lib:

in file: __init__.py
import mod1

Then,

import lib
lib.mod1

would work fine.

$ is not a function - jQuery error

As RPM1984 refers to, this is mostly likely caused by the fact that your script is loading before jQuery is loaded.

Import multiple csv files into pandas and concatenate into one DataFrame

This is how you can do using Colab on Google Drive

import pandas as pd
import glob

path = r'/content/drive/My Drive/data/actual/comments_only' # use your path
all_files = glob.glob(path + "/*.csv")

li = []

for filename in all_files:
    df = pd.read_csv(filename, index_col=None, header=0)
    li.append(df)

frame = pd.concat(li, axis=0, ignore_index=True,sort=True)
frame.to_csv('/content/drive/onefile.csv')

The split() method in Java does not work on a dot (.)

It works fine. Did you read the documentation? The string is converted to a regular expression.

. is the special character matching all input characters.

As with any regular expression special character, you escape with a \. You need an additional \ for the Java string escape.

How to make the script wait/sleep in a simple way in unity

here is more simple way without StartCoroutine:

float t = 0f;
float waittime = 1f;

and inside Update/FixedUpdate:

if (t < 0){
    t += Time.deltaTIme / waittime;
    yield return t;
}

How to convert 1 to true or 0 to false upon model fetch

Here's another option that's longer but may be more readable:

Boolean(Number("0")); // false
Boolean(Number("1")); // true

How to make IPython notebook matplotlib plot inline

You can simulate this problem with a syntax mistake, however, %matplotlib inline won't resolve the issue.

First an example of the right way to create a plot. Everything works as expected with the imports and magic that eNord9 supplied.

df_randNumbers1 = pd.DataFrame(np.random.randint(0,100,size=(100, 6)), columns=list('ABCDEF'))

df_randNumbers1.ix[:,["A","B"]].plot.kde()

However, by leaving the () off the end of the plot type you receive a somewhat ambiguous non-error.

Erronious code:

df_randNumbers1.ix[:,["A","B"]].plot.kde

Example error:

<bound method FramePlotMethods.kde of <pandas.tools.plotting.FramePlotMethods object at 0x000001DDAF029588>>

Other than this one line message, there is no stack trace or other obvious reason to think you made a syntax error. The plot doesn't print.

PHP - concatenate or directly insert variables in string

I use a dot(.) to concate string and variable. like this-

echo "Hello ".$var;

Sometimes, I use curly braces to concate string and variable that looks like this-

echo "Hello {$var}";

How do I retrieve an HTML element's actual width and height?

Here is the code for WKWebView what determines a height of specific Dom element (doesn't work properly for whole page)

let html = "<body><span id=\"spanEl\" style=\"font-family: '\(taskFont.fontName)'; font-size: \(taskFont.pointSize - 4.0)pt; color: rgb(\(red), \(blue), \(green))\">\(textValue)</span></body>"
webView.navigationDelegate = self
webView.loadHTMLString(taskHTML, baseURL: nil)

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    webView.evaluateJavaScript("document.getElementById(\"spanEl\").getBoundingClientRect().height;") { [weak self] (response, error) in
        if let nValue = response as? NSNumber {

        }
    }
}

Why the switch statement cannot be applied on strings?

The reason why has to do with the type system. C/C++ doesn't really support strings as a type. It does support the idea of a constant char array but it doesn't really fully understand the notion of a string.

In order to generate the code for a switch statement the compiler must understand what it means for two values to be equal. For items like ints and enums, this is a trivial bit comparison. But how should the compiler compare 2 string values? Case sensitive, insensitive, culture aware, etc ... Without a full awareness of a string this cannot be accurately answered.

Additionally, C/C++ switch statements are typically generated as branch tables. It's not nearly as easy to generate a branch table for a string style switch.

How to add multiple files to Git at the same time

step1.

git init

step2.

a) for all files

git add -a

b) only specific folder

git add <folder1> <folder2> <etc.>

step3.

git commit -m "Your message about the commit"

step4.

enter image description here

git remote add origin https://github.com/yourUsername/yourRepository.git

step5.

git push -u origin master
git push origin master

if you are face this error than

 ! [rejected]        master -> master (fetch first)
error: failed to push some refs to 'https://github.com/harishkumawat2610/Qt5-with-C-plus-plus.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

Use this command

git push --force origin master

error C4996: 'scanf': This function or variable may be unsafe in c programming

You can add "_CRT_SECURE_NO_WARNINGS" in Preprocessor Definitions.

Right-click your project->Properties->Configuration Properties->C/C++ ->Preprocessor->Preprocessor Definitions.

enter image description here

How to send and retrieve parameters using $state.go toParams and $stateParams?

None of these examples on this page worked for me. This is what I used and it worked well. Some solutions said you cannot combine url with $state.go() but this is not true. The awkward thing is you must define the params for the url and also list the params. Both must be present. Tested on Angular 1.4.8 and UI Router 0.2.15.

In the state add your params to end of state and define the params:

url: 'view?index&anotherKey',
params: {'index': null, 'anotherKey': null}

In your controller your go statement will look like this:

$state.go('view', { 'index': 123, 'anotherKey': 'This is a test' });

Then to pull the params out and use them in your new state's controller (don't forget to pass in $stateParams to your controller function):

var index = $stateParams.index;
var anotherKey = $stateParams.anotherKey;
console.log(anotherKey); //it works!

Force to open "Save As..." popup open at text link click for PDF in HTML

A very easy way to do this, if you need to force download for a single link on your page, is to use the HTML5 download-attribute in the href-link.

See: http://davidwalsh.name/download-attribute

with this you can rename the file that the user will download and at the same time it forces the download.

There has been a debate whether this is good practice or not, but in my case I have an embedded viewer for a PDF file and the viewer does not offer a download link, so i have to provide one separately. Here I want to make sure the user does not get the PDF opened in the web browser, which would be confusing.

This won't necessary open the save as-dialog, but will download the link straight to the preset download destination. And of course if you are doing a site for someone else, and need them to write in manually attributes to their links is probably a bad idea, but if there is way to get the attribute into the links, this can be a light solution.

Put spacing between divs in a horizontal row?

This is because width when provided a % doesn't account for padding/margins. You will need to reduce the amount to possibly 24% or 24.5%. Once this is done you should be good, but you will need to provide different options based on the screen size if you want this to always work correct since you have a hardcoded margin, but a relative size.

Project Links do not work on Wamp Server

Re: Wampserver LocalHost links not working correctly
This is as of June 2014 with Wampserver2.5 (maybe they'll fix this in later builds).
Note: to use LocalHost:8080 instead of LocalHost just make the appropriate changes in the edits mentioned below.

There are 2 aspects of this issue -
The first is to be able to access items under "Your Projects" from the Wamp localhost homepage.
The second is to be able to correctly access items listed in the Wampserver Icon Taskbar's "My Projects" list.

To fix the first (to be able to access items under "Your Projects" from the Wamp localhost homepage) you will need to do the following...

There are 2 edits that you must make in the index.php file located in your wamp\www folder (usually C:\wamp\www)

1) on Line 30 change

  $suppress_localhost = true;

to

  $suppress_localhost = false;

2) on line 338 change

  $projectContents .= '<li><a href="'.($suppress_localhost ? 'http://' : '').$file.'">'.$file.'</a></li>';

to

  $projectContents .= '<li><a href="'.($suppress_localhost ? 'http://' : 'http://localhost//').$file.'">'.$file.'</a></li>';

After you've made the above edits - if the Wampserver is running just refresh the local host page and the changes become immediately effective.

To fix the 2nd item (the Wampserver Icon Taskbar's "My Projects" list): You need to edit C:\wamp\scripts\refresh.php

Locate line 651 and change the section of the line that reads

   Parameters: "http://'.$projectContents[$i].'/"; Glyph: 5

to

   Parameters: "http://localhost//'.$projectContents[$i].'/"; Glyph: 5

After you make these 2nd set of changes you may have to force Wampserver to refresh the "My Projects" list by toggling the Put Online/Offline option at the bottom of the Wamp Icon Tray App.

java.net.URLEncoder.encode(String) is deprecated, what should I use instead?

You should use:

URLEncoder.encode("NAME", "UTF-8");

What does question mark and dot operator ?. mean in C# 6.0?

This is relatively new to C# which makes it easy for us to call the functions with respect to the null or non-null values in method chaining.

old way to achieve the same thing was:

var functionCaller = this.member;
if (functionCaller!= null)
    functionCaller.someFunction(var someParam);

and now it has been made much easier with just:

member?.someFunction(var someParam);

I strongly recommend this doc page.

How can I add a background thread to flask?

Your additional threads must be initiated from the same app that is called by the WSGI server.

The example below creates a background thread that executes every 5 seconds and manipulates data structures that are also available to Flask routed functions.

import threading
import atexit
from flask import Flask

POOL_TIME = 5 #Seconds

# variables that are accessible from anywhere
commonDataStruct = {}
# lock to control access to variable
dataLock = threading.Lock()
# thread handler
yourThread = threading.Thread()

def create_app():
    app = Flask(__name__)

    def interrupt():
        global yourThread
        yourThread.cancel()

    def doStuff():
        global commonDataStruct
        global yourThread
        with dataLock:
        # Do your stuff with commonDataStruct Here

        # Set the next thread to happen
        yourThread = threading.Timer(POOL_TIME, doStuff, ())
        yourThread.start()   

    def doStuffStart():
        # Do initialisation stuff here
        global yourThread
        # Create your thread
        yourThread = threading.Timer(POOL_TIME, doStuff, ())
        yourThread.start()

    # Initiate
    doStuffStart()
    # When you kill Flask (SIGTERM), clear the trigger for the next thread
    atexit.register(interrupt)
    return app

app = create_app()          

Call it from Gunicorn with something like this:

gunicorn -b 0.0.0.0:5000 --log-config log.conf --pid=app.pid myfile:app

How to scroll HTML page to given anchor?

This is a working script that will scroll the page to the anchor. To setup just give the anchor link an id that matches the name attribute of the anchor that you want to scroll to.

<script>
jQuery(document).ready(function ($){ 
 $('a').click(function (){ 
  var id = $(this).attr('id');
  console.log(id);
  if ( id == 'cet' || id == 'protein' ) {
   $('html, body').animate({ scrollTop: $('[name="' + id + '"]').offset().top}, 'slow'); 
  }
 }); 
});
</script>

How to find the date of a day of the week from a date using PHP?

If your date is already a DateTime or DateTimeImmutable you can use the format method.

$day_of_week = intval($date_time->format('w'));

The format string is identical to the one used by the date function.


To answer the intended question:

$date_time->modify($target_day_of_week - $day_of_week . ' days');

Oracle Convert Seconds to Hours:Minutes:Seconds

Assuming your time is called st.etime below and stored in seconds, here is what I use. This handles times where the seconds are greater than 86399 seconds (which is 11:59:59 pm)

case when st.etime > 86399 then to_char(to_date(st.etime - 86400,'sssss'),'HH24:MI:SS') else to_char(to_date(st.etime,'sssss'),'HH24:MI:SS') end readable_time

how to convert milliseconds to date format in android?

fun convertLongToTimeWithLocale(){
    val dateAsMilliSecond: Long = 1602709200000
    val date = Date(dateAsMilliSecond)
    val language = "en"
    val formattedDateAsDigitMonth = SimpleDateFormat("dd/MM/yyyy", Locale(language))
    val formattedDateAsShortMonth = SimpleDateFormat("dd MMM yyyy", Locale(language))
    val formattedDateAsLongMonth = SimpleDateFormat("dd MMMM yyyy", Locale(language))
    Log.d("month as digit", formattedDateAsDigitMonth.format(date))
    Log.d("month as short", formattedDateAsShortMonth.format(date))
    Log.d("month as long", formattedDateAsLongMonth.format(date))
}

output:

month as digit: 15/10/2020
month as short: 15 Oct 2020 
month as long : 15 October 2020

You can change the value defined as 'language' due to your require. Here is the all language codes: Java language codes

iOS app with framework crashed on device, dyld: Library not loaded, Xcode 6 Beta

After trying all the methods available on internet and my own trial and error tricks 100 times. Finally I was able to solve it. – Apeksha Sahu 6 mins ago
Goto iTunes in Mac --> accounts-->Authorize this computer – Apeksha Sahu 5 mins ago
second step.... Goto developer in settings in iPad and iPhone and reindex with identifiers and clear trust computers everything. It worked for me........ ....... After reinstalling Mac OSHigh seria 10.13.15 version from Mac OS seirra beta latest version, to reinstalling Xcode latest version, after updating all certificates. etc etc etc... as many methods as you can think I did. – enter image description here

splitting a string based on tab in the file

Python has support for CSV files in the eponymous csv module. It is relatively misnamed since it support much more that just comma separated values.

If you need to go beyond basic word splitting you should take a look. Say, for example, because you are in need to deal with quoted values...

Programmatically obtain the phone number of the Android phone

There is a new Android api that allows the user to select their phonenumber without the need for a permission. Take a look at: https://android-developers.googleblog.com/2017/10/effective-phone-number-verification.html

// Construct a request for phone numbers and show the picker
private void requestHint() {
    HintRequest hintRequest = new HintRequest.Builder()
       .setPhoneNumberIdentifierSupported(true)
       .build();

    PendingIntent intent = Auth.CredentialsApi.getHintPickerIntent(
        apiClient, hintRequest);
    startIntentSenderForResult(intent.getIntentSender(),
        RESOLVE_HINT, null, 0, 0, 0);
} 

How to query the permissions on an Oracle directory?

This should give you the roles, users and permissions granted on a directory:

SELECT * 
  FROM all_tab_privs 
 WHERE table_name = 'your_directory';  --> needs to be upper case

And yes, it IS in the all_TAB_privs view ;-) A better name for that view would be something like "ALL_OBJECT_PRIVS", since it also includes PL/SQL objects and their execute permissions as well.

How to load image files with webpack file-loader

Alternatively you can write the same like

{
    test: /\.(svg|png|jpg|jpeg|gif)$/,
    include: 'path of input image directory',
    use: {
        loader: 'file-loader',
        options: {
            name: '[path][name].[ext]',
            outputPath: 'path of output image directory'
        }
    }
}

and then use simple import

import varName from 'relative path';

and in jsx write like <img src={varName} ..../>

.... are for other image attributes

Design Android EditText to show error message as described by google

If anybody still facing the error with using google's design library as mentioned in the answer then, please use this as commented by @h_k which is -

Instead of calling setError on TextInputLayout, You might be using setError on EditText itself.

Android - Spacing between CheckBox and text

In my case I solved this problem using this following CheckBox attribute in the XML:

*

android:paddingLeft="@dimen/activity_horizontal_margin"

*

How to create JSON post to api using C#

Have you tried using the WebClient class?

you should be able to use

string result = "";
using (var client = new WebClient())
{
    client.Headers[HttpRequestHeader.ContentType] = "application/json"; 
    result = client.UploadString(url, "POST", json);
}
Console.WriteLine(result);

Documentation at

http://msdn.microsoft.com/en-us/library/system.net.webclient%28v=vs.110%29.aspx

http://msdn.microsoft.com/en-us/library/d0d3595k%28v=vs.110%29.aspx

C++ multiline string literal

You can also do this:

const char *longString = R""""(
This is 
a very 
long 
string
)"""";

How can I find the first and last date in a month using PHP?

You can use DateTimeImmutable::modify() :


$date = DateTimeImmutable::createFromFormat('Y-m-d', '2021-02-13');

var_dump($date->modify('first day of this month')->format('Y-m-d')); // string(10) "2021-02-01"
var_dump($date->modify('last day of this month')->format('Y-m-d')); // string(10) "2021-02-28"

MySQL error 1241: Operand should contain 1 column(s)

Syntax error, remove the ( ) from select.

insert into table2 (name, subject, student_id, result)
select name, subject, student_id, result
from table1;

Embed image in a <button> element

Add new folder with name of Images in your project. Put some images into Images folder. Then it will work fine.

<input type="image" src="~/Images/Desert.jpg" alt="Submit" width="48" height="48">

JavaScript object: access variable property by name as string

Since I was helped with my project by the answer above (I asked a duplicate question and was referred here), I am submitting an answer (my test code) for bracket notation when nesting within the var:

_x000D_
_x000D_
<html>_x000D_
<head>_x000D_
  <script type="text/javascript">_x000D_
    function displayFile(whatOption, whatColor) {_x000D_
      var Test01 = {_x000D_
        rectangle: {_x000D_
          red: "RectangleRedFile",_x000D_
          blue: "RectangleBlueFile"_x000D_
        },_x000D_
        square: {_x000D_
          red: "SquareRedFile",_x000D_
          blue: "SquareBlueFile"_x000D_
        }_x000D_
      };_x000D_
      var filename = Test01[whatOption][whatColor];_x000D_
      alert(filename);_x000D_
    }_x000D_
  </script>_x000D_
</head>_x000D_
<body>_x000D_
  <p onclick="displayFile('rectangle', 'red')">[ Rec Red ]</p>_x000D_
  <br/>_x000D_
  <p onclick="displayFile('square', 'blue')">[ Sq Blue ]</p>_x000D_
  <br/>_x000D_
  <p onclick="displayFile('square', 'red')">[ Sq Red ]</p>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Understanding events and event handlers in C#

Great technical answers in the post! I have nothing technically to add to that.

One of the main reasons why new features appear in languages and software in general is marketing or company politics! :-) This must not be under estimated!

I think this applies to certain extend to delegates and events too! i find them useful and add value to the C# language, but on the other hand the Java language decided not to use them! they decided that whatever you are solving with delegates you can already solve with existing features of the language i.e. interfaces e.g.

Now around 2001 Microsoft released the .NET framework and the C# language as a competitor solution to Java, so it was good to have NEW FEATURES that Java doesn't have.

X-Frame-Options Allow-From multiple domains

How about an approach that not only allows multiple domains, but allows dynamic domains.

The use case here is with a Sharepoint app part which loads our site inside of Sharepoint via an iframe. The problem is that sharepoint has dynamic subdomains such as https://yoursite.sharepoint.com. So for IE, we need to specify ALLOW-FROM https://.sharepoint.com

Tricky business, but we can get it done knowing two facts:

  1. When an iframe loads, it only validates the X-Frame-Options on the first request. Once the iframe is loaded, you can navigate within the iframe and the header isn't checked on subsequent requests.

  2. Also, when an iframe is loaded, the HTTP referer is the parent iframe url.

You can leverage these two facts server side. In ruby, I'm using the following code:

  uri = URI.parse(request.referer)
  if uri.host.match(/\.sharepoint\.com$/)
    url = "https://#{uri.host}"
    response.headers['X-Frame-Options'] = "ALLOW-FROM #{url}"
  end

Here we can dynamically allow domains based upon the parent domain. In this case, we ensure that the host ends in sharepoint.com keeping our site safe from clickjacking.

I'd love to hear feedback on this approach.

how do I query sql for a latest record date for each user

SELECT t1.username, t1.date, value
FROM MyTable as t1
INNER JOIN (SELECT username, MAX(date)
            FROM MyTable
            GROUP BY username) as t2 ON  t2.username = t1.username AND t2.date = t1.date

How to close an iframe within iframe itself

its kind of hacky but it works well-ish

 function close_frame(){
    if(!window.should_close){
        window.should_close=1;
    }else if(window.should_close==1){
        location.reload();
        //or iframe hide or whatever
    }
 }

 <iframe src="iframe_index.php" onload="close_frame()"></iframe>

then inside the frame

$('#close_modal_main').click(function(){
        window.location = 'iframe_index.php?close=1';
});

and if you want to get fancy through a

if(isset($_GET['close'])){
  die;
}

at the top of your frame page to make that reload unnoticeable

so basically the first time the frame loads it doesnt hide itself but the next time it loads itll call the onload function and the parent will have a the window var causing the frame to close

How does paintComponent work?

Calling object.paintComponent(g) is an error.

Instead this method is called automatically when the panel is created. The paintComponent() method can also be called explicitly by the repaint() method defined in Component class.

The effect of calling repaint() is that Swing automatically clears the graphic on the panel and executes the paintComponent method to redraw the graphics on this panel.

How to use the unsigned Integer in Java 8 and Java 9?

Well, even in Java 8, long and int are still signed, only some methods treat them as if they were unsigned. If you want to write unsigned long literal like that, you can do

static long values = Long.parseUnsignedLong("18446744073709551615");

public static void main(String[] args) {
    System.out.println(values); // -1
    System.out.println(Long.toUnsignedString(values)); // 18446744073709551615
}

Difference between | and || or & and && for comparison

The instance in which you're using a single character (i.e. | or &) is a bitwise comparison of the results. As long as your language evaluates these expressions to a binary value they should return the same results. As a best practice, however, you should use the logical operator as that's what you mean (I think).

Click events on Pie Charts in Chart.js

Update: As @Soham Shetty comments, getSegmentsAtEvent(event) only works for 1.x and for 2.x getElementsAtEvent should be used.

.getElementsAtEvent(e)

Looks for the element under the event point, then returns all elements at the same data index. This is used internally for 'label' mode highlighting.

Calling getElementsAtEvent(event) on your Chart instance passing an argument of an event, or jQuery event, will return the point elements that are at that the same position of that event.

canvas.onclick = function(evt){
    var activePoints = myLineChart.getElementsAtEvent(evt);
    // => activePoints is an array of points on the canvas that are at the same position as the click event.
};

Example: https://jsfiddle.net/u1szh96g/208/


Original answer (valid for Chart.js 1.x version):

You can achieve this using getSegmentsAtEvent(event)

Calling getSegmentsAtEvent(event) on your Chart instance passing an argument of an event, or jQuery event, will return the segment elements that are at that the same position of that event.

From: Prototype Methods

So you can do:

$("#myChart").click( 
    function(evt){
        var activePoints = myNewChart.getSegmentsAtEvent(evt);           
        /* do something */
    }
);  

Here is a full working example:

<html>
    <head>
        <script type="text/javascript" src="http://code.jquery.com/jquery-2.0.2.js"></script>
        <script type="text/javascript" src="Chart.js"></script>
        <script type="text/javascript">
            var data = [
                {
                    value: 300,
                    color:"#F7464A",
                    highlight: "#FF5A5E",
                    label: "Red"
                },
                {
                    value: 50,
                    color: "#46BFBD",
                    highlight: "#5AD3D1",
                    label: "Green"
                },
                {
                    value: 100,
                    color: "#FDB45C",
                    highlight: "#FFC870",
                    label: "Yellow"
                }
            ];

            $(document).ready( 
                function () {
                    var ctx = document.getElementById("myChart").getContext("2d");
                    var myNewChart = new Chart(ctx).Pie(data);

                    $("#myChart").click( 
                        function(evt){
                            var activePoints = myNewChart.getSegmentsAtEvent(evt);
                            var url = "http://example.com/?label=" + activePoints[0].label + "&value=" + activePoints[0].value;
                            alert(url);
                        }
                    );                  
                }
            );
        </script>
    </head>
    <body>
        <canvas id="myChart" width="400" height="400"></canvas>
    </body>
</html>

JRE installation directory in Windows

In the command line you can type java -version

git pull error "The requested URL returned error: 503 while accessing"

Try disabling all the system wide HTTP and HTTPS proxies:

export http_proxy="" 
export https_proxy=""
export HTTP_PROXY=""
export HTTPS_PROXY=""

How to set tbody height with overflow scroll

Based on this answer, here's a minimal solution if you're already using Bootstrap:

div.scrollable-table-wrapper {
  height: 500px;
  overflow: auto;

  thead tr th {
    position: sticky;
    top: 0;
  }
}
<div class="scrollable-table-wrapper">
  <table class="table">
    <thead>...</thead>
    <tbody>...</tbody>
  </table>
</div>

Tested on Bootstrap v3

I'm getting an error "invalid use of incomplete type 'class map'

I am just providing another case where you can get this error message. The solution will be the same as Adam has mentioned above. This is from a real code and I renamed the class name.

class FooReader {
  public:
     /** Constructor */
     FooReader() : d(new FooReaderPrivate(this)) { }  // will not compile here
     .......
  private:
     FooReaderPrivate* d;
};

====== In a separate file =====
class FooReaderPrivate {
  public:
     FooReaderPrivate(FooReader*) : parent(p) { }
  private:
     FooReader* parent;
};

The above will no pass the compiler and get error: invalid use of incomplete type FooReaderPrivate. You basically have to put the inline portion into the *.cpp implementation file. This is OK. What I am trying to say here is that you may have a design issue. Cross reference of two classes may be necessary some cases, but I would say it is better to avoid them at the start of the design. I would be wrong, but please comment then I will update my posting.

Disable-web-security in Chrome 48+

In a terminal put these:

cd C:\Program Files (x86)\Google\Chrome\Application

chrome.exe --disable-web-security --user-data-dir="c:/chromedev"

Embed website into my site

Put content from other site in iframe

<iframe src="/othersiteurl" width="100%" height="300">
  <p>Your browser does not support iframes.</p>
</iframe>