Programs & Examples On #Eclipse templates

Run local python script on remote server

Although this question isn't quite new and an answer was already chosen, I would like to share another nice approach.

Using the paramiko library - a pure python implementation of SSH2 - your python script can connect to a remote host via SSH, copy itself (!) to that host and then execute that copy on the remote host. Stdin, stdout and stderr of the remote process will be available on your local running script. So this solution is pretty much independent of an IDE.

On my local machine, I run the script with a cmd-line parameter 'deploy', which triggers the remote execution. Without such a parameter, the actual code intended for the remote host is run.

import sys
import os

def main():
    print os.name

if __name__ == '__main__':
    try:
        if sys.argv[1] == 'deploy':
            import paramiko

            # Connect to remote host
            client = paramiko.SSHClient()
            client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            client.connect('remote_hostname_or_IP', username='john', password='secret')

            # Setup sftp connection and transmit this script
            sftp = client.open_sftp()
            sftp.put(__file__, '/tmp/myscript.py')
            sftp.close()

            # Run the transmitted script remotely without args and show its output.
            # SSHClient.exec_command() returns the tuple (stdin,stdout,stderr)
            stdout = client.exec_command('python /tmp/myscript.py')[1]
            for line in stdout:
                # Process each line in the remote output
                print line

            client.close()
            sys.exit(0)
    except IndexError:
        pass

    # No cmd-line args provided, run script normally
    main()

Exception handling is left out to simplify this example. In projects with multiple script files you will probably have to put all those files (and other dependencies) on the remote host.

What is object serialization?

You can think of serialization as the process of converting an object instance into a sequence of bytes (which may be binary or not depending on the implementation).

It is very useful when you want to transmit one object data across the network, for instance from one JVM to another.

In Java, the serialization mechanism is built into the platform, but you need to implement the Serializable interface to make an object serializable.

You can also prevent some data in your object from being serialized by marking the attribute as transient.

Finally you can override the default mechanism, and provide your own; this may be suitable in some special cases. To do this, you use one of the hidden features in java.

It is important to notice that what gets serialized is the "value" of the object, or the contents, and not the class definition. Thus methods are not serialized.

Here is a very basic sample with comments to facilitate its reading:

import java.io.*;
import java.util.*;

// This class implements "Serializable" to let the system know
// it's ok to do it. You as programmer are aware of that.
public class SerializationSample implements Serializable {

    // These attributes conform the "value" of the object.

    // These two will be serialized;
    private String aString = "The value of that string";
    private int    someInteger = 0;

    // But this won't since it is marked as transient.
    private transient List<File> unInterestingLongLongList;

    // Main method to test.
    public static void main( String [] args ) throws IOException  { 

        // Create a sample object, that contains the default values.
        SerializationSample instance = new SerializationSample();

        // The "ObjectOutputStream" class has the default 
        // definition to serialize an object.
        ObjectOutputStream oos = new ObjectOutputStream( 
                               // By using "FileOutputStream" we will 
                               // Write it to a File in the file system
                               // It could have been a Socket to another 
                               // machine, a database, an in memory array, etc.
                               new FileOutputStream(new File("o.ser")));

        // do the magic  
        oos.writeObject( instance );
        // close the writing.
        oos.close();
    }
}

When we run this program, the file "o.ser" is created and we can see what happened behind.

If we change the value of: someInteger to, for example Integer.MAX_VALUE, we may compare the output to see what the difference is.

Here's a screenshot showing precisely that difference:

alt text

Can you spot the differences? ;)

There is an additional relevant field in Java serialization: The serialversionUID but I guess this is already too long to cover it.

How can I clear event subscriptions in C#?

Setting the event to null inside the class works. When you dispose a class you should always set the event to null, the GC has problems with events and may not clean up the disposed class if it has dangling events.

Difference of keywords 'typename' and 'class' in templates?

There is no difference between using OR ; i.e. it is a convention used by C++ programmers. I myself prefer as it more clearly describes it use; i.e. defining a template with a specific type :)

Note: There is one exception where you do have to use class (and not typename) when declaring a template template parameter:

template <template class T> class C { }; // valid!

template <template typename T> class C { }; // invalid!

In most cases, you will not be defining a nested template definition, so either definition will work -- just be consistent in your use...

Can't draw Histogram, 'x' must be numeric

Note that you could as well plot directly from ce (after the comma removing) using the column name :

hist(ce$Weight)

(As opposed to using hist(ce[1]), which would lead to the same "must be numeric" error.)

This also works for a database query result.

How to fix "containing working copy admin area is missing" in SVN?

Just in case anyone wants yet another solution:

  1. Check in your new folder as "foldername2"
  2. Go into Tortise SVN repo browser
  3. Rename "foldername2" to "foldername"
  4. In windows explorer do an update

Hope it helps someone.

-Ev

Run Python script at startup in Ubuntu

Create file ~/.config/autostart/MyScript.desktop with

[Desktop Entry]
Encoding=UTF-8
Name=MyScript
Comment=MyScript
Icon=gnome-info
Exec=python /home/your_path/script.py
Terminal=false
Type=Application
Categories=

X-GNOME-Autostart-enabled=true
X-GNOME-Autostart-Delay=0

It helps me!

Extract a subset of a dataframe based on a condition involving a field

Here are the two main approaches. I prefer this one for its readability:

bar <- subset(foo, location == "there")

Note that you can string together many conditionals with & and | to create complex subsets.

The second is the indexing approach. You can index rows in R with either numeric, or boolean slices. foo$location == "there" returns a vector of T and F values that is the same length as the rows of foo. You can do this to return only rows where the condition returns true.

foo[foo$location == "there", ]

Freeze screen in chrome debugger / DevTools panel for popover inspection?

Got it working. Here was my procedure:

  1. Browse to the desired page
  2. Open the dev console - F12 on Windows/Linux or option + ? + J on macOS
  3. Select the Sources tab in chrome inspector
  4. In the web browser window, hover over the desired element to initiate the popover
  5. Hit F8 on Windows/Linux (or fn + F8 on macOS) while the popover is showing. If you have clicked anywhere on the actual page F8 will do nothing. Your last click needs to be somewhere in the inspector, like the sources tab
  6. Go to the Elements tab in inspector
  7. Find your popover (it will be nested in the trigger element's HTML)
  8. Have fun modifying the CSS

React - how to pass state to another component

Move all of your state and your handleClick function from Header to your MainWrapper component.

Then pass values as props to all components that need to share this functionality.

class MainWrapper extends React.Component {
    constructor() {
        super();
        this.state = {
            sidbarPushCollapsed: false,
            profileCollapsed: false
        };
        this.handleClick = this.handleClick.bind(this);
    }
    handleClick() {
        this.setState({
            sidbarPushCollapsed: !this.state.sidbarPushCollapsed,
            profileCollapsed: !this.state.profileCollapsed

        });
    }
    render() {
        return (
           //...
           <Header 
               handleClick={this.handleClick} 
               sidbarPushCollapsed={this.state.sidbarPushCollapsed}
               profileCollapsed={this.state.profileCollapsed} />
        );

Then in your Header's render() method, you'd use this.props:

<button type="button" id="sidbarPush" onClick={this.props.handleClick} profile={this.props.profileCollapsed}>

Reverse HashMap keys and values in Java

If the values are not unique, the safe way to inverse the map is by using java 8's groupingBy function

Map<String, Integer> map = new HashMap<>();
map.put("a",1);
map.put("b",2);

Map<Integer, List<String>> mapInversed = 
map.entrySet()
   .stream()
   .collect(Collectors.groupingBy(Map.Entry::getValue, Collectors.mapping(Map.Entry::getKey, Collectors.toList())))

How to select specific form element in jQuery?

I prefer an id descendant selector of your #form2, like this:

$("#form2 #name").val("Hello World!");

http://api.jquery.com/descendant-selector/

Detect if a Form Control option button is selected in VBA

If you are using a Form Control, you can get the same property as ActiveX by using OLEFormat.Object property of the Shape Object. Better yet assign it in a variable declared as OptionButton to get the Intellisense kick in.

Dim opt As OptionButton

With Sheets("Sheet1") ' Try to be always explicit
    Set opt = .Shapes("Option Button 1").OLEFormat.Object ' Form Control
    Debug.Pring opt.Value ' returns 1 (true) or -4146 (false)
End With

But then again, you really don't need to know the value.
If you use Form Control, you associate a Macro or sub routine with it which is executed when it is selected. So you just need to set up a sub routine that identifies which button is clicked and then execute a corresponding action for it.

For example you have 2 Form Control Option Buttons.

Sub CheckOptions()
    Select Case Application.Caller
    Case "Option Button 1"
    ' Action for option button 1
    Case "Option Button 2"
    ' Action for option button 2
    End Select
End Sub

In above code, you have only one sub routine assigned to both option buttons.
Then you test which called the sub routine by checking Application.Caller.
This way, no need to check whether the option button value is true or false.

Define constant variables in C++ header

You generally shouldn't use e.g. const int in a header file, if it's included in several source files. That is because then the variables will be defined once per source file (translation units technically speaking) because global const variables are implicitly static, taking up more memory than required.

You should instead have a special source file, Constants.cpp that actually defines the variables, and then have the variables declared as extern in the header file.

Something like this header file:

// Protect against multiple inclusions in the same source file
#ifndef CONSTANTS_H
#define CONSTANTS_H

extern const int CONSTANT_1;

#endif

And this in a source file:

const int CONSTANT_1 = 123;

How to get object size in memory?

In debug mode

load SOS

and execute dumpheap command.

"The import org.springframework cannot be resolved."

Had the same problem in Eclipse STS. Changing the scope in the pom from "provided" to "compile" fixed the problem and when I changed it back everything was still OK.

How to update/refresh specific item in RecyclerView

You can use the notifyItemChanged(int position) method from the RecyclerView.Adapter class. From the documentation:

Notify any registered observers that the item at position has changed. Equivalent to calling notifyItemChanged(position, null);.

This is an item change event, not a structural change event. It indicates that any reflection of the data at position is out of date and should be updated. The item at position retains the same identity.

As you already have the position, it should work for you.

How would you count occurrences of a string (actually a char) within a string?

In C#, a nice String SubString counter is this unexpectedly tricky fellow:

public static int CCount(String haystack, String needle)
{
    return haystack.Split(new[] { needle }, StringSplitOptions.None).Length - 1;
}

Deleting folders in python recursively

For Linux users, you can simply run the shell command in a pythonic way

import os
os.system("rm -r /home/user/folder1  /home/user/folder2  ...")

If facing any issue then instead of rm -r use rm -rf but remember f will delete the directory forcefully.

Where rm stands for remove, -r for recursively and -rf for recursively + forcefully.

Note: It doesn't matter either the directories are empty or not, they'll get deleted.

Getting the difference between two Dates (months/days/hours/minutes/seconds) in Swift

If someone needs to display all time units e.g "hours minutes seconds" not just "hours". Let's say the time difference between two dates is 1hour 59minutes 20seconds. This function will display "1h 59m 20s".

Here is my Objective-C code:

extension NSDate {

    func offsetFrom(date: NSDate) -> String {

        let dayHourMinuteSecond: NSCalendarUnit = [.Day, .Hour, .Minute, .Second]
        let difference = NSCalendar.currentCalendar().components(dayHourMinuteSecond, fromDate: date, toDate: self, options: [])

        let seconds = "\(difference.second)s"
        let minutes = "\(difference.minute)m" + " " + seconds
        let hours = "\(difference.hour)h" + " " + minutes
        let days = "\(difference.day)d" + " " + hours

        if difference.day    > 0 { return days }
        if difference.hour   > 0 { return hours }
        if difference.minute > 0 { return minutes }
        if difference.second > 0 { return seconds }
        return ""
    }

}

In Swift 3+:

extension Date {

    func offsetFrom(date: Date) -> String {

        let dayHourMinuteSecond: Set<Calendar.Component> = [.day, .hour, .minute, .second]
        let difference = NSCalendar.current.dateComponents(dayHourMinuteSecond, from: date, to: self)

        let seconds = "\(difference.second ?? 0)s"
        let minutes = "\(difference.minute ?? 0)m" + " " + seconds
        let hours = "\(difference.hour ?? 0)h" + " " + minutes
        let days = "\(difference.day ?? 0)d" + " " + hours

        if let day = difference.day, day          > 0 { return days }
        if let hour = difference.hour, hour       > 0 { return hours }
        if let minute = difference.minute, minute > 0 { return minutes }
        if let second = difference.second, second > 0 { return seconds }
        return ""
    }

}

Generating all permutations of a given string

This can be done iteratively by simply inserting each letter of the string in turn in all locations of the previous partial results.

We start with [A], which with B becomes [BA, AB], and with C, [CBA, BCA, BAC, CAB, etc].

The running time would be O(n!), which, for the test case ABCD, is 1 x 2 x 3 x 4.

In the above product, the 1 is for A, the 2 is for B, etc.

Dart sample:

void main() {

  String insertAt(String a, String b, int index)
  {
    return a.substring(0, index) + b + a.substring(index);
  }

  List<String> Permute(String word) {

    var letters = word.split('');

    var p_list = [ letters.first ];

    for (var c in letters.sublist(1)) {

      var new_list = [ ];

      for (var p in p_list)
        for (int i = 0; i <= p.length; i++)
          new_list.add(insertAt(p, c, i));

      p_list = new_list;
    }

    return p_list;
  }

  print(Permute("ABCD"));

}

Header and footer in CodeIgniter

Using This Helper For Dynamic Template Loading

//  get  Template 
    function get_template($template_name, $vars = array(), $return = FALSE) {
        $CI = & get_instance();

        $content = "";
        $last = $CI - > uri - > total_segments();

        if ($CI - > uri - > segment($last) != 'tab') {
            $content = $CI - > load - > view('Header', $vars, $return);
            $content. = $CI - > load - > view('Sidebar', $vars, $return);
        }

        $content. = $CI - > load - > view($template_name, $vars, $return);

        if ($CI - > uri - > segment($last) != 'tab') {
            $content. = $CI - > load - > view('Footer', $vars, $return);
        }

        if ($return) {
            return $content;
        }
    }

Unable to install boto3

I had a similar problem, but the accepted answer did not resolve it - I was not using a virtual environment. This is what I had to do:

sudo python -m pip install boto3

I do not know why this behaved differently from sudo pip install boto3.

jQuery selector regular expressions

I'm just giving my real time example:

In native javascript I used following snippet to find the elements with ids starts with "select2-qownerName_select-result".

document.querySelectorAll("[id^='select2-qownerName_select-result']");

When we shifted from javascript to jQuery we've replaced above snippet with the following which involves less code changes without disturbing the logic.

$("[id^='select2-qownerName_select-result']")

sql - insert into multiple tables in one query

I had the same problem. I solve it with a for loop.

Example:

If I want to write in 2 identical tables, using a loop

for x = 0 to 1

 if x = 0 then TableToWrite = "Table1"
 if x = 1 then TableToWrite = "Table2"
  Sql = "INSERT INTO " & TableToWrite & " VALUES ('1','2','3')"
NEXT

either

ArrTable = ("Table1", "Table2")

for xArrTable = 0 to Ubound(ArrTable)
 Sql = "INSERT INTO " & ArrTable(xArrTable) & " VALUES ('1','2','3')"
NEXT

If you have a small query I don't know if this is the best solution, but if you your query is very big and it is inside a dynamical script with if/else/case conditions this is a good solution.

Increasing nesting function calls limit

This error message comes specifically from the XDebug extension. PHP itself does not have a function nesting limit. Change the setting in your php.ini:

xdebug.max_nesting_level = 200

or in your PHP code:

ini_set('xdebug.max_nesting_level', 200);

As for if you really need to change it (i.e.: if there's a alternative solution to a recursive function), I can't tell without the code.

Eclipse - Failed to load class "org.slf4j.impl.StaticLoggerBinder"

Did you update the project (right-click on the project, "Maven" > "Update project...")? Otherwise, you need to check if pom.xml contains the necessary slf4j dependencies, e.g.:

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>jcl-over-slf4j</artifactId>
        <version>1.7.0</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.7.0</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.0</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.14</version>
    </dependency>

What does '<?=' mean in PHP?

I hope it doesn't get deprecated. While writing <? blah code ?> is fairly unnecessary and confusable with XHTML, <?= isn't, for obvious reasons. Unfortunately I don't use it, because short_open_tag seems to be disabled more and more.

Update: I do use <?= again now, because it is enabled by default with PHP 5.4.0. See http://php.net/manual/en/language.basic-syntax.phptags.php

Check a radio button with javascript

By using document.getElementById() function you don't have to pass # before element's id.

Code:

document.getElementById('_1234').checked = true;

Demo: JSFiddle

Difference between java.lang.RuntimeException and java.lang.Exception

In simple words, if your client/user can recover from the Exception then make it a Checked Exception, if your client can't do anything to recover from the Exception then make it Unchecked RuntimeException. E.g, a RuntimeException would be a programmatic error, like division by zero, no user can do anything about it but the programmer himself, then it is a RuntimeException.

How to pre-populate the sms body text via an html link

For using Android you use below code

<a href="sms:+32665?body=reg fb1>Send SMS</a>

For iOS you can use below code

<a href="sms:+32665&body=reg fb1>Send SMS</a>

below code working for both iOs and Android

<a href="sms:+32665?&body=reg fb1>Send SMS</a>

How to use private Github repo as npm dependency

It can be done via https and oauth or ssh.

https and oauth: create an access token that has "repo" scope and then use this syntax:

"package-name": "git+https://<github_token>:[email protected]/<user>/<repo>.git"

or

ssh: setup ssh and then use this syntax:

"package-name": "git+ssh://[email protected]:<user>/<repo>.git"

(note the use of colon instead of slash before user)

Query to get only numbers from a string

First create this UDF

CREATE FUNCTION dbo.udf_GetNumeric
(
  @strAlphaNumeric VARCHAR(256)
)
RETURNS VARCHAR(256)
AS
BEGIN
  DECLARE @intAlpha INT
  SET @intAlpha = PATINDEX('%[^0-9]%', @strAlphaNumeric)
  BEGIN
    WHILE @intAlpha > 0
    BEGIN
      SET @strAlphaNumeric = STUFF(@strAlphaNumeric, @intAlpha, 1, '' )
      SET @intAlpha = PATINDEX('%[^0-9]%', @strAlphaNumeric )
    END
  END
  RETURN ISNULL(@strAlphaNumeric,0)
END
GO

Now use the function as

SELECT dbo.udf_GetNumeric(column_name) 
from table_name

SQL FIDDLE

I hope this solved your problem.

Reference

A regular expression to exclude a word/string

As you want to exclude both words, you need a conjuction:

^/(?!ignoreme$)(?!ignoreme2$)[a-z0-9]+$

Now both conditions must be true (neither ignoreme nor ignoreme2 is allowed) to have a match.

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

Just use DataRow.IsNull. It has overrides accepting a column index, a column name, or a DataColumn object as parameters.

Example using the column index:

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

And although the function is called IsNull it really compares with DbNull (which is exactly what you need).


What if I want to check for DbNull but I don't have a DataRow? Use Convert.IsDBNull.

Move textfield when keyboard appears swift

If you are like me who has tried all the above solutions and still your problem is not solved, I have a got a great solution for you that works like a charm. First I want clarify few things about some of solutions mentioned above.

  1. In my case IQkeyboardmanager was working only when there is no auto layout applied on the elements, if it is applied then IQkeyboard manager will not work the way we think.
  2. Same thing with upward movement of self.view.
  3. i have wriiten a objective c header with a swift support for pushing UITexfield upward when user clicks on it, solving the problem of keyboard covering the UITextfield : https://github.com/coolvasanth/smart_keyboard.
  4. One who has An intermediate or higher level in iOS app development can easily understand the repository and implement it. All the best

Java: Clear the console

By combining all the given answers, this method should work on all environments:

public static void clearConsole() {
    try {
        if (System.getProperty("os.name").contains("Windows")) {
            new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
        }
        else {
            System.out.print("\033\143");
        }
    } catch (IOException | InterruptedException ex) {}
}

How to remove the left part of a string?

def remove_prefix(text, prefix):
    return text[len(prefix):] if text.startswith(prefix) else text

how to calculate percentage in python

def percentage_match(mainvalue,comparevalue):
    if mainvalue >= comparevalue:
        matched_less = mainvalue - comparevalue
        no_percentage_matched = 100 - matched_less*100.0/mainvalue
        no_percentage_matched = str(no_percentage_matched) + ' %'
        return no_percentage_matched 
    else:
        print('please checkout your value')

print percentage_match(100,10)
Ans = 10.0 %

Find the nth occurrence of substring in a string

>>> s="abcdefabcdefababcdef"
>>> j=0
>>> for n,i in enumerate(s):
...   if s[n:n+2] =="ab":
...     print n,i
...     j=j+1
...     if j==2: print "2nd occurence at index position: ",n
...
0 a
6 a
2nd occurence at index position:  6
12 a
14 a

Format date with Moment.js

You Probably Don't Need Moment.js Anymore

Moment is great time manipulation library but it's considered as a legacy project, and the team is recommending to use other libraries.

date-fns is one of the best lightweight libraries, it's modular, so you can pick the functions you need and reduce bundle size (issue & statement).

Another common argument against using Moment in modern applications is its size. Moment doesn't work well with modern "tree shaking" algorithms, so it tends to increase the size of web application bundles.

import { format } from 'date-fns' // 21K (gzipped: 5.8K)
import moment from 'moment' // 292.3K (gzipped: 71.6K)

Format date with date-fns:

// moment.js
moment().format('MM/DD/YYYY');
// => "12/18/2020"

// date-fns
import { format } from 'date-fns'
format(new Date(), 'MM/dd/yyyy');
// => "12/18/2020"

More on cheat sheet with the list of functions which you can use to replace moment.js: You-Dont-Need-Momentjs

Javascript: output current datetime in YYYY/mm/dd hh:m:sec format

With jQuery date format :

$.format.date(new Date(), 'yyyy/MM/dd HH:mm:ss');

https://github.com/phstc/jquery-dateFormat

Enjoy

Reduce git repository size

This should not affect everyone, but one of the semi-hidden reasons of the repository size being large could be Git submodules.

You might have added one or more submodules, but stopped using it at some time, and some files remained in .git/modules directory. To make redundant submodule files gone away, see this question.

However, just like the main repository, the other way is to navigate to the submodule directory in .git/modules, and do a, for example, git gc --aggressive --prune.

These should have a good impact in the repository size, but as long as you use Git submodules, e.g. especially with large libraries, your repository size should not change drastically.

Vue.js redirection to another page

window.location = url;

'url' is the web url you want to redirect.

Getting unique items from a list

Apart from the Distinct extension method of LINQ, you could use a HashSet<T> object that you initialise with your collection. This is most likely more efficient than the LINQ way, since it uses hash codes (GetHashCode) rather than an IEqualityComparer).

In fact, if it's appropiate for your situation, I would just use a HashSet for storing the items in the first place.

Generating random numbers with normal distribution in Excel

About the recalculation:

You can keep your set of random values from changing every time you make an adjustment, by adjusting the automatic recalculation, to: manual recalculate. (Re)calculations are then only done when you press F9. Or shift F9.

See this link (though for older excel version than the current 2013) for some info about it: https://support.office.com/en-us/article/Change-formula-recalculation-iteration-or-precision-73fc7dac-91cf-4d36-86e8-67124f6bcce4.

What Scala web-frameworks are available?

I tend to use JAX-RS using Jersey (you can write nice resource beans in Scala, Java or Groovy) to write RESTul web applications. Then I use Scalate for the rendering the views using one of the various template languages (JADE, Scaml, Ssp (Scala Server Pages), Mustache, etc.).

repository element was not specified in the POM inside distributionManagement element or in -DaltDep loymentRepository=id::layout::url parameter

In your pom.xml you should add distributionManagement configuration to where to deploy.

In the following example I have used file system as the locations.

<distributionManagement>
       <repository>
         <id>internal.repo</id>
         <name>Internal repo</name>
         <url>file:///home/thara/testesb/in</url>
       </repository>
   </distributionManagement>

you can add another location while deployment by using the following command (but to avoid above error you should have at least 1 repository configured) :

mvn deploy -DaltDeploymentRepository=internal.repo::default::file:///home/thara/testesb/in

Closure in Java 7

According to Tom Hawtin

A closure is a block of code that can be referenced (and passed around) with access to the variables of the enclosing scope.

Now I'm trying to emulate the JavaScript closure example on Wikipedia, with a "straigth" translation to Java, in the hope to be useful:

//ECMAScript
var f, g;
function foo() {
  var x = 0;
  f = function() { return ++x; };
  g = function() { return --x; };
  x = 1;
  print('inside foo, call to f(): ' + f()); // "2"  
}
foo();
print('call to g(): ' + g()); // "1"
print('call to f(): ' + f()); // "2"

Now the java part: Function1 is "Functor" interface with arity 1 (one argument). Closure is the class implementing the Function1, a concrete Functor that acts as function (int -> int). In the main() method I just instantiate foo as a Closure object, replicating the calls from the JavaScript example. The IntBox class is just a simple container, it behave like an array of 1 int:

int a[1] = {0}

interface Function1   {
    public final IntBag value = new IntBag();
    public int apply();
}

class Closure implements Function1 {
   private IntBag x = value;
   Function1 f;
   Function1 g;

   @Override
   public int apply()  {
    // print('inside foo, call to f(): ' + f()); // "2"
    // inside apply, call to f.apply()
       System.out.println("inside foo, call to f.apply(): " + f.apply());
       return 0;
   }

   public Closure() {
       f = new Function1() {
           @Override
           public int apply()  {
               x.add(1);
                return x.get();
           }
       };
       g = new Function1() {
           @Override
           public int apply()  {
               x.add(-1);
               return x.get();
           }
       };
    // x = 1;
       x.set(1);
   }
}
public class ClosureTest {
    public static void main(String[] args) {
        // foo()
        Closure foo = new Closure();
        foo.apply();
        // print('call to g(): ' + g()); // "1"
        System.out.println("call to foo.g.apply(): " + foo.g.apply());
        // print('call to f(): ' + f()); // "2"
        System.out.println("call to foo.f.apply(): " + foo.f.apply());

    }
}

It prints:

inside foo, call to f.apply(): 2
call to foo.g.apply(): 1
call to foo.f.apply(): 2 

NameError: global name 'unicode' is not defined - in Python 3

If you need to have the script keep working on python2 and 3 as I did, this might help someone

import sys
if sys.version_info[0] >= 3:
    unicode = str

and can then just do for example

foo = unicode.lower(foo)

How to limit the number of selected checkboxes?

$("input:checkbox").click(function(){
    if ($("input:checkbox:checked").length > 3){
      return false;
   }
});

What does it mean when the size of a VARCHAR2 in Oracle is declared as 1 byte?

The VARCHAR datatype is synonymous with the VARCHAR2 datatype. To avoid possible changes in behavior, always use the VARCHAR2 datatype to store variable-length character strings.

If your database runs on a single-byte character set (e.g. US7ASCII, WE8MSWIN1252 or WE8ISO8859P1) it does not make any difference whether you use VARCHAR2(x BYTE) or VARCHAR2(x CHAR).

It makes only a difference when your DB runs on multi-byte character set (e.g. AL32UTF8 or AL16UTF16). You can simply see it in this example:

CREATE TABLE my_table (
    VARCHAR2_byte VARCHAR2(1 BYTE), 
    VARCHAR2_char VARCHAR2(1 CHAR)
);

INSERT INTO my_table (VARCHAR2_char) VALUES ('€');
1 row created.

INSERT INTO my_table (VARCHAR2_char) VALUES ('ü');
1 row created.

INSERT INTO my_table (VARCHAR2_byte) VALUES ('€');
INSERT INTO my_table (VARCHAR2_byte) VALUES ('€')
Error at line 10
ORA-12899: value too large for column "MY_TABLE"."VARCHAR2_BYTE" (actual: 3, maximum: 1)

INSERT INTO my_table (VARCHAR2_byte) VALUES ('ü')
Error at line 11
ORA-12899: value too large for column "MY_TABLE"."VARCHAR2_BYTE" (actual: 2, maximum: 1)

VARCHAR2(1 CHAR) means you can store up to 1 character, no matter how many byte it has. In case of Unicode one character may occupy up to 4 bytes.

VARCHAR2(1 BYTE) means you can store a character which occupies max. 1 byte.

If you don't specify either BYTE or CHAR then the default is taken from NLS_LENGTH_SEMANTICS session parameter.

Unless you have Oracle 12c where you can set MAX_STRING_SIZE=EXTENDED the limit is VARCHAR2(4000 CHAR)

However, VARCHAR2(4000 CHAR) does not mean you are guaranteed to store up to 4000 characters. The limit is still 4000 bytes, so in worst case you may store only up to 1000 characters in such field.

See this example ( in UTF-8 occupies 3 bytes):

CREATE TABLE my_table2(VARCHAR2_char VARCHAR2(4000 CHAR));

BEGIN
    INSERT INTO my_table2 VALUES ('€€€€€€€€€€');
    FOR i IN 1..7 LOOP
        UPDATE my_table2 SET VARCHAR2_char = VARCHAR2_char ||VARCHAR2_char;
    END LOOP;
END;
/

SELECT LENGTHB(VARCHAR2_char) , LENGTHC(VARCHAR2_char) FROM my_table2;

LENGTHB(VARCHAR2_CHAR) LENGTHC(VARCHAR2_CHAR)
---------------------- ----------------------
                  3840                   1280
1 row selected.


UPDATE my_table2 SET VARCHAR2_char = VARCHAR2_char ||VARCHAR2_char;

UPDATE my_table2 SET VARCHAR2_char = VARCHAR2_char ||VARCHAR2_char
Error at line 1
ORA-01489: result of string concatenation is too long

See also Examples and limits of BYTE and CHAR semantics usage (NLS_LENGTH_SEMANTICS) (Doc ID 144808.1)

Cannot delete directory with Directory.Delete(path, true)

I´ve solved with this millenary technique (you can leave the Thread.Sleep on his own in the catch)

bool deleted = false;
        do
        {
            try
            {
                Directory.Delete(rutaFinal, true);                    
                deleted = true;
            }
            catch (Exception e)
            {
                string mensaje = e.Message;
                if( mensaje == "The directory is not empty.")
                Thread.Sleep(50);
            }
        } while (deleted == false);

'Missing contentDescription attribute on image' in XML

Add

tools:ignore="ContentDescription"

to your image. Make sure you have xmlns:tools="http://schemas.android.com/tools" . in your root layout.

Encode URL in JavaScript?

You have three options:

  • escape() will not encode: @*/+

  • encodeURI() will not encode: ~!@#$&*()=:/,;?+'

  • encodeURIComponent() will not encode: ~!*()'

But in your case, if you want to pass a URL into a GET parameter of other page, you should use escape or encodeURIComponent, but not encodeURI.

See Stack Overflow question Best practice: escape, or encodeURI / encodeURIComponent for further discussion.

Saving an Object (Data persistence)

You can use anycache to do the job for you. It considers all the details:

  • It uses dill as backend, which extends the python pickle module to handle lambda and all the nice python features.
  • It stores different objects to different files and reloads them properly.
  • Limits cache size
  • Allows cache clearing
  • Allows sharing of objects between multiple runs
  • Allows respect of input files which influence the result

Assuming you have a function myfunc which creates the instance:

from anycache import anycache

class Company(object):
    def __init__(self, name, value):
        self.name = name
        self.value = value

@anycache(cachedir='/path/to/your/cache')    
def myfunc(name, value)
    return Company(name, value)

Anycache calls myfunc at the first time and pickles the result to a file in cachedir using an unique identifier (depending on the function name and its arguments) as filename. On any consecutive run, the pickled object is loaded. If the cachedir is preserved between python runs, the pickled object is taken from the previous python run.

For any further details see the documentation

adding .css file to ejs

You can use this

     var fs = require('fs');
     var myCss = {
         style : fs.readFileSync('./style.css','utf8');
     };

     app.get('/', function(req, res){
       res.render('index.ejs', {
       title: 'My Site',
       myCss: myCss
      });
     });

put this on template

   <%- myCss.style %>

just build style.css

  <style>
    body { 
     background-color: #D8D8D8;
     color: #444;
   }
  </style>

I try this for some custom css. It works for me

How can I create an executable JAR with dependencies using Maven?

I went through every one of these responses looking to make a fat executable jar containing all dependencies and none of them worked right. The answer is the shade plugin, its very easy and straightforward.

    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-shade-plugin</artifactId>
      <version>2.3</version>
      <executions>
         <!-- Run shade goal on package phase -->
        <execution>
        <phase>package</phase>
        <goals>
            <goal>shade</goal>
        </goals>
        <configuration>
          <transformers>
             <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                <mainClass>path.to.MainClass</mainClass>
             </transformer>
          </transformers>
        </configuration>
          </execution>
      </executions>
    </plugin>

Be aware that your dependencies need to have a scope of compile or runtime for this to work properly.

This example came from mkyong.com

how to create a Java Date object of midnight today and midnight tomorrow?

java.time

If you are using Java 8 and later, you can try the java.time package (Tutorial):

LocalDate tomorrow = LocalDate.now().plusDays(1);
Date endDate = Date.from(tomorrow.atStartOfDay(ZoneId.systemDefault()).toInstant());

Multiple maven repositories in one gradle file

In short you have to do like this

repositories {
  maven { url "http://maven.springframework.org/release" }
  maven { url "https://maven.fabric.io/public" }
}

Detail:

You need to specify each maven URL in its own curly braces. Here is what I got working with skeleton dependencies for the web services project I’m going to build up:

apply plugin: 'java'

sourceCompatibility = 1.7
version = '1.0'

repositories {
  maven { url "http://maven.springframework.org/release" }
  maven { url "http://maven.restlet.org" }
  mavenCentral()
}

dependencies {
  compile group:'org.restlet.jee', name:'org.restlet', version:'2.1.1'
  compile group:'org.restlet.jee', name:'org.restlet.ext.servlet',version.1.1'
  compile group:'org.springframework', name:'spring-web', version:'3.2.1.RELEASE'
  compile group:'org.slf4j', name:'slf4j-api', version:'1.7.2'
  compile group:'ch.qos.logback', name:'logback-core', version:'1.0.9'
  testCompile group:'junit', name:'junit', version:'4.11'
}

Blog

What arguments are passed into AsyncTask<arg1, arg2, arg3>?

Keep it simple!

An AsyncTask is background task which runs in the background thread. It takes an Input, performs Progress and gives Output.

ie AsyncTask<Input,Progress,Output>.

In my opinion the main source of confusion comes when we try to memorize the parameters in the AsyncTask.
The key is Don't memorize.
If you can visualize what your task really needs to do then writing the AsyncTask with the correct signature would be a piece of cake.
Just figure out what your Input, Progress and Output are and you will be good to go.

For example: enter image description here

Heart of the AsyncTask!

doInBackgound() method is the most important method in an AsyncTask because

  • Only this method runs in the background thread and publish data to UI thread.
  • Its signature changes with the AsyncTask parameters.

So lets see the relationship

enter image description here

doInBackground() and onPostExecute(),onProgressUpdate() are also related

enter image description here

Show me the code
So how will I write the code for DownloadTask?

DownloadTask extends AsyncTask<String,Integer,String>{

      @Override
      public void onPreExecute()
      {}

      @Override
      public String doInbackGround(String... params)
      {
               // Download code
               int downloadPerc = // calculate that
               publish(downloadPerc);

               return "Download Success";
      }

      @Override
      public void onPostExecute(String result)
      {
          super.onPostExecute(result);
      }

      @Override
      public void onProgressUpdate(Integer... params)
      {
             // show in spinner, access UI elements
      }

}

How will you run this Task

new DownLoadTask().execute("Paradise.mp3");

How to ignore whitespace in a regular expression subject string?

If you only want to allow spaces, then

\bc *a *t *s\b

should do it. To also allow tabs, use

\bc[ \t]*a[ \t]*t[ \t]*s\b

Remove the \b anchors if you also want to find cats within words like bobcats or catsup.

Compiling php with curl, where is curl installed?

Try just --with-curl, without specifying a location, and see if it'll find it by itself.

Label axes on Seaborn Barplot

You can also set the title of your chart by adding the title parameter as follows

ax.set(xlabel='common xlabel', ylabel='common ylabel', title='some title')

Curl not recognized as an internal or external command, operable program or batch file

Steps to install curl in windows

Install cURL on Windows

There are 4 steps to follow to get cURL installed on Windows.

Step 1 and Step 2 is to install SSL library. Step 3 is to install cURL. Step 4 is to install a recent certificate

Step One: Install Visual C++ 2008 Redistributables

From https://www.microsoft.com/en-za/download/details.aspx?id=29 For 64bit systems Visual C++ 2008 Redistributables (x64) For 32bit systems Visual C++ 2008 Redistributables (x32)

Step Two: Install Win(32/64) OpenSSL v1.0.0k Light

From http://www.shininglightpro.com/products/Win32OpenSSL.html For 64bit systems Win64 OpenSSL v1.0.0k Light For 32bit systems Win32 OpenSSL v1.0.0k Light

Step Three: Install cURL

Depending on if your system is 32 or 64 bit, download the corresponding** curl.exe.** For example, go to the Win64 - Generic section and download the Win64 binary with SSL support (the one where SSL is not crossed out). Visit http://curl.haxx.se/download.html

Copy curl.exe to C:\Windows\System32

Step Four: Install Recent Certificates

Do not skip this step. Download a recent copy of valid CERT files from https://curl.haxx.se/ca/cacert.pem Copy it to the same folder as you placed curl.exe (C:\Windows\System32) and rename it as curl-ca-bundle.crt

If you have already installed curl or after doing the above steps, add the directory where it's installed to the windows path:

1 - From the Desktop, right-click My Computer and click Properties.
2 - Click Advanced System Settings .
3 - In the System Properties window click the Environment Variables button.
4 - Select Path and click Edit.
5 - Append ;c:\path to curl directory at the end.
5 - Click OK.
6 - Close and re-open the command prompt

Nginx not picking up site in sites-enabled?

Changing from:

include /etc/nginx/sites-enabled/*; 

to

include /etc/nginx/sites-enabled/*.*; 

fixed my issue

Why is my power operator (^) not working?

There is no way to use the ^ (Bitwise XOR) operator to calculate the power of a number. Therefore, in order to calculate the power of a number we have two options, either we use a while loop or the pow() function.

1. Using a while loop.

#include <stdio.h>

int main() {

    int base, expo;
    long long result = 1;

    printf("Enter a base no.: ");
    scanf("%d", &base);

    printf("Enter an exponent: ");
    scanf("%d", &expo);

    while (expo != 0) {
        result *= base;
        --expo;
    }

    printf("Answer = %lld", result);
    return 0;
}    
             

2. Using the pow() function

#include <math.h>
#include <stdio.h>

int main() {

    double base, exp, result;

    printf("Enter a base number: ");
    scanf("%lf", &base);

    printf("Enter an exponent: ");
    scanf("%lf", &exp);

    // calculate the power of our input numbers
    result = pow(base, exp);

    printf("%.1lf^%.1lf = %.2lf", base, exp, result);

    return 0;
}
     

Selenium and xpath: finding a div with a class/id and verifying text inside

To account for leading and trailing whitespace, you probably want to use normalize-space()

//div[contains(@class, 'Caption') and normalize-space(.)='Model saved']

and

//div[@id='alertLabel' and normalize-space(.)='Save to server successful']

Note that //div[contains(@class, 'Caption') and normalize-space(.//text())='Model saved'] also works.

Check if program is running with bash shell script?

If you want to execute that command, you should probably change:

PROCESS_NUM='ps -ef | grep "$1" | grep -v "grep" | wc -l'

to:

PROCESS_NUM=$(ps -ef | grep "$1" | grep -v "grep" | wc -l)

Python: Best way to add to sys.path relative to the current running script

I use:

from site import addsitedir

Then, can use any relative directory ! addsitedir('..\lib') ; the two dots implies move (up) one directory first.

Remember that it all depends on what your current working directory your starting from. If C:\Joe\Jen\Becky, then addsitedir('..\lib') imports to your path C:\Joe\Jen\lib

C:\
  |__Joe
      |_ Jen
      |     |_ Becky
      |_ lib

Why does Node.js' fs.readFile() return a buffer instead of string?

Async:

fs.readFile('test.txt', 'utf8', callback);

Sync:

var content = fs.readFileSync('test.txt', 'utf8');

Get the value for a listbox item by index

Suppose you want the value of the first item.

ListBox list = new ListBox();
Console.Write(list.Items[0].Value);

How to convert an iterator to a stream?

This is possible in Java 9.

Stream.generate(() -> null)
    .takeWhile(x -> iterator.hasNext())
    .map(n -> iterator.next())
    .forEach(System.out::println);

How can I mark a foreign key constraint using Hibernate annotations?

@Column is not the appropriate annotation. You don't want to store a whole User or Question in a column. You want to create an association between the entities. Start by renaming Questions to Question, since an instance represents a single question, and not several ones. Then create the association:

@Entity
@Table(name = "UserAnswer")
public class UserAnswer {

    // this entity needs an ID:
    @Id
    @Column(name="useranswer_id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "user_id")
    private User user;

    @ManyToOne
    @JoinColumn(name = "question_id")
    private Question question;

    @Column(name = "response")
    private String response;

    //getter and setter 
}

The Hibernate documentation explains that. Read it. And also read the javadoc of the annotations.

How to filter by IP address in Wireshark?

If you only care about that particular machine's traffic, use a capture filter instead, which you can set under Capture -> Options.

host 192.168.1.101

Wireshark will only capture packet sent to or received by 192.168.1.101. This has the benefit of requiring less processing, which lowers the chances of important packets being dropped (missed).

How to exclude *AutoConfiguration classes in Spring Boot JUnit tests?

I struggled with this as well and found a simple pattern to isolate the test context after a cursory read of the @ComponentScan docs.

/**
* Type-safe alternative to {@link #basePackages} for specifying the packages
* to scan for annotated components. The package of each class specified will be scanned.
* Consider creating a special no-op marker class or interface in each package
* that serves no purpose other than being referenced by this attribute.
*/
Class<?>[] basePackageClasses() default {};

  1. Create a package for your spring tests, ("com.example.test").
  2. Create a marker interface in the package as a context qualifier.
  3. Provide the marker interface reference as a parameter to basePackageClasses.

Example


IsolatedTest.java

package com.example.test;

@RunWith(SpringJUnit4ClassRunner.class)
@ComponentScan(basePackageClasses = {TestDomain.class})
@SpringApplicationConfiguration(classes = IsolatedTest.Config.class)
public class IsolatedTest {

     String expected = "Read the documentation on @ComponentScan";
     String actual = "Too lazy when I can just search on Stack Overflow.";

      @Test
      public void testSomething() throws Exception {
          assertEquals(expected, actual);
      }

      @ComponentScan(basePackageClasses = {TestDomain.class})
      public static class Config {
      public static void main(String[] args) {
          SpringApplication.run(Config.class, args);
      }
    }
}

...

TestDomain.java

package com.example.test;

public interface TestDomain {
//noop marker
}

What is the most effective way to get the index of an iterator of an std::vector?

I just discovered this: https://greek0.net/boost-range/boost-adaptors-indexed.html

    for (const auto & element : str | boost::adaptors::indexed(0)) {
        std::cout << element.index()
                  << " : "
                  << element.value()
                  << std::endl;
    }

Search code inside a Github project

Go here: https://github.com/search and enter "pattern repo:user_name/repo_name".

For example, to search for cnn_learner in the fastai repo of user fastai, enter this:

cnn_learner repo:fastai/fastai

That's it. The only annoyance is you'll need an extra click. It will tell you:

We couldn’t find any repositories matching 'cnn_learner repo:fastai/fastai'

because by default it searches for repositories matching that search string...

So just click on the left on "Code" and it will display what you want.

Or get the code search results directly with a URL like this:

https://github.com/search?q=cnn_learner+repo%3Afastai%2Ffastai&type=code

Convert object to JSON in Android

public class Producto {

int idProducto;
String nombre;
Double precio;



public Producto(int idProducto, String nombre, Double precio) {

    this.idProducto = idProducto;
    this.nombre = nombre;
    this.precio = precio;

}
public int getIdProducto() {
    return idProducto;
}
public void setIdProducto(int idProducto) {
    this.idProducto = idProducto;
}
public String getNombre() {
    return nombre;
}
public void setNombre(String nombre) {
    this.nombre = nombre;
}
public Double getPrecio() {
    return precio;
}
public void setPrecio(Double precio) {
    this.precio = precio;
}

public String toJSON(){

    JSONObject jsonObject= new JSONObject();
    try {
        jsonObject.put("id", getIdProducto());
        jsonObject.put("nombre", getNombre());
        jsonObject.put("precio", getPrecio());

        return jsonObject.toString();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return "";
    }

}

How do I view the Explain Plan in Oracle Sql developer?

Explain only shows how the optimizer thinks the query will execute.

To show the real plan, you will need to run the sql once. Then use the same session run the following:

@yoursql 
select * from table(dbms_xplan.display_cursor()) 

This way can show the real plan used during execution. There are several other ways in showing plan using dbms_xplan. You can Google with term "dbms_xplan".

Javascript Date Validation ( DD/MM/YYYY) & Age Checking

with leading zero for day and month

var pattern =/^(0[1-9]|1[0-9]|2[0-9]|3[0-1])\/(0[1-9]|1[0-2])\/([0-9]{4})$/;

and with both leading zero/without leading zero for day and month

var pattern =/^(0?[1-9]|1[0-9]|2[0-9]|3[0-1])\/(0?[1-9]|1[0-2])\/([0-9]{4})$/;

WebApi's {"message":"an error has occurred"} on IIS7, not in IIS Express

My swagger XML file was not deployed into \bin:

GlobalConfiguration.Configuration
  .EnableSwagger(c =>
  {
    c.SingleApiVersion("v1", "SwaggerDemoApi");
    c.IncludeXmlComments(string.Format(@"{0}\bin\SwaggerDemoApi.XML", 
                         System.AppDomain.CurrentDomain.BaseDirectory));
    c.DescribeAllEnumsAsStrings();
  })

http://wmpratt.com/swagger-and-asp-net-web-api-part-1/

enter image description here

It had to be set in the Release Configuration as well as in the Debug Configuration.

node.js Error: connect ECONNREFUSED; response from server

i ran the local mysql database, but not in administrator mode, which threw this error

package javax.servlet.http does not exist

If you are working with maven project, then add following dependency to your pom.xml

<dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.0.1</version>
        <scope>provided</scope>
</dependency>

How can I get the assembly file version

Use this:

((AssemblyFileVersionAttribute)Attribute.GetCustomAttribute(
    Assembly.GetExecutingAssembly(), 
    typeof(AssemblyFileVersionAttribute), false)
).Version;

Or this:

new Version(System.Windows.Forms.Application.ProductVersion);

target input by type and name (selector)

You want a multiple attribute selector

$("input[type='checkbox'][name='ProductCode']").each(function(){ ...

or

$("input:checkbox[name='ProductCode']").each(function(){ ...

It would be better to use a CSS class to identify those that you want to select however as a lot of the modern browsers implement the document.getElementsByClassName method which will be used to select elements and be much faster than selecting by the name attribute

How to get duration, as int milli's and float seconds from <chrono>?

I don't know what "milliseconds and float seconds" means, but this should give you an idea:

#include <chrono>
#include <thread>
#include <iostream>

int main()
{
  auto then = std::chrono::system_clock::now();
  std::this_thread::sleep_for(std::chrono::seconds(1));
  auto now = std::chrono::system_clock::now();
  auto dur = now - then;
  typedef std::chrono::duration<float> float_seconds;
  auto secs = std::chrono::duration_cast<float_seconds>(dur);
  std::cout << secs.count() << '\n';
}

Android Color Picker

I ended up here looking for a HSV color picker that offered transparency and copy/paste of the hex value. None of the existing answers met those needs, so here's the library I ended up writing:

HSV-Alpha Color Picker for Android (GitHub).

HSV-Alpha Color Picker Demo (Google Play).

I hope it's useful for somebody else.

Color Picker Dialog

How to specify HTTP error code?

The version of the errorHandler middleware bundled with some (perhaps older?) versions of express seems to have the status code hardcoded. The version documented here: http://www.senchalabs.org/connect/errorHandler.html on the other hand lets you do what you are trying to do. So, perhaps trying upgrading to the latest version of express/connect.

python time + timedelta equivalent

You can change time() to now() for it to work

from datetime import datetime, timedelta
datetime.now() + timedelta(hours=1)

How can I pad an integer with zeros on the left?

If performance is important in your case you could do it yourself with less overhead compared to the String.format function:

/**
 * @param in The integer value
 * @param fill The number of digits to fill
 * @return The given value left padded with the given number of digits
 */
public static String lPadZero(int in, int fill){

    boolean negative = false;
    int value, len = 0;

    if(in >= 0){
        value = in;
    } else {
        negative = true;
        value = - in;
        in = - in;
        len ++;
    }

    if(value == 0){
        len = 1;
    } else{         
        for(; value != 0; len ++){
            value /= 10;
        }
    }

    StringBuilder sb = new StringBuilder();

    if(negative){
        sb.append('-');
    }

    for(int i = fill; i > len; i--){
        sb.append('0');
    }

    sb.append(in);

    return sb.toString();       
}

Performance

public static void main(String[] args) {
    Random rdm;
    long start; 

    // Using own function
    rdm = new Random(0);
    start = System.nanoTime();

    for(int i = 10000000; i != 0; i--){
        lPadZero(rdm.nextInt(20000) - 10000, 4);
    }
    System.out.println("Own function: " + ((System.nanoTime() - start) / 1000000) + "ms");

    // Using String.format
    rdm = new Random(0);        
    start = System.nanoTime();

    for(int i = 10000000; i != 0; i--){
        String.format("%04d", rdm.nextInt(20000) - 10000);
    }
    System.out.println("String.format: " + ((System.nanoTime() - start) / 1000000) + "ms");
}

Result

Own function: 1697ms

String.format: 38134ms

how to write value into cell with vba code without auto type conversion?

Cells(1,1).Value2 = "'123,456"

note the single apostrophe before the number - this will signal to excel that whatever follows has to be interpreted as text.

Parse error: syntax error, unexpected T_ECHO in

Missing ; after var_dump($row)

Get Cell Value from a DataTable in C#

You can iterate DataTable like this:

private void button1_Click(object sender, EventArgs e)
{
    for(int i = 0; i< dt.Rows.Count;i++)
        for (int j = 0; j <dt.Columns.Count ; j++)
        {
            object o = dt.Rows[i].ItemArray[j];
            //if you want to get the string
            //string s = o = dt.Rows[i].ItemArray[j].ToString();
        }
}

Depending on the type of the data in the DataTable cell, you can cast the object to whatever you want.

How to display HTML <FORM> as inline element?

Add a inline wrapper.

<div style='display:flex'>
<form>
 <p>Read this sentence</p>
 <input type='submit' value='or push this button' />
</form>
<div>
    <p>Message here</p>
</div>

Notepad++ change text color?

You can Change it from:

Menu Settings -> Style Configurator

See on screenshot:

enter image description here

Docker - Container is not running

docker run -it <image_id> /bin/bash

Run in interactive mode executing then bash shell

Is it possible to do a sparse checkout without checking out the whole repository first?

I had a similar use case, except I wanted to checkout only the commit for a tag and prune the directories. Using --depth 1 makes it really sparse and can really speed things up.

mkdir myrepo
cd myrepo
git init
git config core.sparseCheckout true
git remote add origin <url>  # Note: no -f option
echo "path/within_repo/to/subdir/" > .git/info/sparse-checkout
git fetch --depth 1 origin tag <tagname>
git checkout <tagname>

Pythonic way to check if a file exists?

To check if a path is an existing file:

os.path.isfile(path)

Return True if path is an existing regular file. This follows symbolic links, so both islink() and isfile() can be true for the same path.

How to insert multiple rows from a single query using eloquent/fluent

It is really easy to do a bulk insert in Laravel using Eloquent or the query builder.

You can use the following approach.

$data = [
    ['user_id'=>'Coder 1', 'subject_id'=> 4096],
    ['user_id'=>'Coder 2', 'subject_id'=> 2048],
    //...
];

Model::insert($data); // Eloquent approach
DB::table('table')->insert($data); // Query Builder approach

In your case you already have the data within the $query variable.

How to dispatch a Redux action with a timeout?

Redux itself is a pretty verbose library, and for such stuff you would have to use something like Redux-thunk, which will give a dispatch function, so you will be able to dispatch closing of the notification after several seconds.

I have created a library to address issues like verbosity and composability, and your example will look like the following:

import { createTile, createSyncTile } from 'redux-tiles';
import { sleep } from 'delounce';

const notifications = createSyncTile({
  type: ['ui', 'notifications'],
  fn: ({ params }) => params.data,
  // to have only one tile for all notifications
  nesting: ({ type }) => [type],
});

const notificationsManager = createTile({
  type: ['ui', 'notificationManager'],
  fn: ({ params, dispatch, actions }) => {
    dispatch(actions.ui.notifications({ type: params.type, data: params.data }));
    await sleep(params.timeout || 5000);
    dispatch(actions.ui.notifications({ type: params.type, data: null }));
    return { closed: true };
  },
  nesting: ({ type }) => [type],
});

So we compose sync actions for showing notifications inside async action, which can request some info the background, or check later whether the notification was closed manually.

Most concise way to test string equality (not object equality) for Ruby strings or symbols?

Your code sample didn't expand on part of your topic, namely symbols, and so that part of the question went unanswered.

If you have two strings, foo and bar, and both can be either a string or a symbol, you can test equality with

foo.to_s == bar.to_s

It's a little more efficient to skip the string conversions on operands with known type. So if foo is always a string

foo == bar.to_s

But the efficiency gain is almost certainly not worth demanding any extra work on behalf of the caller.

Prior to Ruby 2.2, avoid interning uncontrolled input strings for the purpose of comparison (with strings or symbols), because symbols are not garbage collected, and so you can open yourself to denial of service through resource exhaustion. Limit your use of symbols to values you control, i.e. literals in your code, and trusted configuration properties.

Ruby 2.2 introduced garbage collection of symbols.

How do I give PHP write access to a directory?

Set the owner of the directory to the user running apache. Often nobody on linux

chown nobody:nobody <dirname>

This way your folder will not be world writable, but still writable for apache :)

Transparent color of Bootstrap-3 Navbar

The class is .navbar-default. You need to create a class on your custom css .navbar-default.And follow the css code. Also if you don’t want box-shadow on your menu, you can put on the same class.

 .navbar-default {
      background-color:transparent !important;
      border-color:transparent;
      background-image:none;
      box-shadow:none;  
 }

enter image description here

To change font navbar color, the class is to change – .navbar-default .navbar-nav>li>a see the code bellow:

  .navbar-default .navbar-nav>li>a {
     font-size:20px; 
     color:#fff; 
 }

ref : http://twitterbootstrap.org/bootstrap-navbar-background-color-transparent/

How to enable mod_rewrite for Apache 2.2

There's obviously more than one way to do it, but I would suggest using the more standard:

ErrorDocument 404 /index.php?page=404

POST request not allowed - 405 Not Allowed - nginx, even with headers included

This is the real proxy redirection to the intended server.

server {
  listen          80;
  server_name     localhost;
location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-NginX-Proxy true;
    proxy_pass http://xx.xxx.xxx.xxx/;
    proxy_redirect off;
    proxy_set_header Host $host;

  }
}

Windows.history.back() + location.reload() jquery

You can't do window.history.back(); and location.reload(); in the same function.

window.history.back() breaks the javascript flow and redirects to previous page, location.reload() is never processed.

location.reload() has to be called on the page you redirect to when using window.history.back().

I would used an url to redirect instead of history.back, that gives you both a redirect and refresh.

How do I enable EF migrations for multiple contexts to separate databases?

In case you already have a "Configuration" with many migrations and want to keep this as is, you can always create a new "Configuration" class, give it another name, like

class MyNewContextConfiguration : DbMigrationsConfiguration<MyNewDbContext>
{
   ...
}

then just issue the command

Add-Migration -ConfigurationTypeName MyNewContextConfiguration InitialMigrationName

and EF will scaffold the migration without problems. Finally update your database, from now on, EF will complain if you don't tell him which configuration you want to update:

Update-Database -ConfigurationTypeName MyNewContextConfiguration 

Done.

You don't need to deal with Enable-Migrations as it will complain "Configuration" already exists, and renaming your existing Configuration class will bring issues to the migration history.

You can target different databases, or the same one, all configurations will share the __MigrationHistory table nicely.

How can I select the record with the 2nd highest salary in database Oracle?

You should use something like this:

SELECT *
FROM (select salary2.*, rownum rnum from
         (select * from salary ORDER BY salary_amount DESC) salary2
  where rownum <= 2 )
WHERE rnum >= 2;

What is causing ERROR: there is no unique constraint matching given keys for referenced table?

when you do UNIQUE as a table level constraint as you have done then what your defining is a bit like a composite primary key see ddl constraints, here is an extract

"This specifies that the *combination* of values in the indicated columns is unique across the whole table, though any one of the columns need not be (and ordinarily isn't) unique."

this means that either field could possibly have a non unique value provided the combination is unique and this does not match your foreign key constraint.

most likely you want the constraint to be at column level. so rather then define them as table level constraints, 'append' UNIQUE to the end of the column definition like name VARCHAR(60) NOT NULL UNIQUE or specify indivdual table level constraints for each field.

Concatenating multiple text files into a single file in Bash

How about this approach?

find . -type f -name '*.txt' -exec cat {} + >> output.txt

Get list from pandas DataFrame column headers

Surprised I haven't seen this posted so far, so I'll just leave this here.

Extended Iterable Unpacking (python3.5+): [*df] and Friends

Unpacking generalizations (PEP 448) have been introduced with Python 3.5. So, the following operations are all possible.

df = pd.DataFrame('x', columns=['A', 'B', 'C'], index=range(5))
df

   A  B  C
0  x  x  x
1  x  x  x
2  x  x  x
3  x  x  x
4  x  x  x 

If you want a list....

[*df]
# ['A', 'B', 'C']

Or, if you want a set,

{*df}
# {'A', 'B', 'C'}

Or, if you want a tuple,

*df,  # Please note the trailing comma
# ('A', 'B', 'C')

Or, if you want to store the result somewhere,

*cols, = df  # A wild comma appears, again
cols
# ['A', 'B', 'C']

... if you're the kind of person who converts coffee to typing sounds, well, this is going consume your coffee more efficiently ;)

P.S.: if performance is important, you will want to ditch the solutions above in favour of

df.columns.to_numpy().tolist()
# ['A', 'B', 'C']

This is similar to Ed Chum's answer, but updated for v0.24 where .to_numpy() is preferred to the use of .values. See this answer (by me) for more information.

Visual Check
Since I've seen this discussed in other answers, you can utilise iterable unpacking (no need for explicit loops).

print(*df)
A B C

print(*df, sep='\n')
A
B
C

Critique of Other Methods

Don't use an explicit for loop for an operation that can be done in a single line (List comprehensions are okay).

Next, using sorted(df) does not preserve the original order of the columns. For that, you should use list(df) instead.

Next, list(df.columns) and list(df.columns.values) are poor suggestions (as of the current version, v0.24). Both Index (returned from df.columns) and NumPy arrays (returned by df.columns.values) define .tolist() method which is faster and more idiomatic.

Lastly, listification i.e., list(df) should only be used as a concise alternative to the aforementioned methods for python <= 3.4 where extended unpacking is not available.

PHP GuzzleHttp. How to make a post request with params?

Try this

$client = new \GuzzleHttp\Client();
$client->post(
    'http://www.example.com/user/create',
    array(
        'form_params' => array(
            'email' => '[email protected]',
            'name' => 'Test user',
            'password' => 'testpassword'
        )
    )
);

SQL Views - no variables?

You could use WITH to define your expressions. Then do a simple Sub-SELECT to access those definitions.

CREATE VIEW MyView
AS
  WITH MyVars (SomeVar, Var2)
  AS (
    SELECT
      'something' AS 'SomeVar',
      123 AS 'Var2'
  )

  SELECT *
  FROM MyTable
  WHERE x = (SELECT SomeVar FROM MyVars)

Combining paste() and expression() functions in plot labels

Very nice example using paste and substitute to typeset both symbols (mathplot) and variables at http://vis.supstat.com/2013/04/mathematical-annotation-in-r/

Here is a ggplot adaptation

library(ggplot2)
x_mean <- 1.5
x_sd <- 1.2
N <- 500

n <- ggplot(data.frame(x <- rnorm(N, x_mean, x_sd)),aes(x=x)) +
    geom_bar() + stat_bin() +
    labs(title=substitute(paste(
             "Histogram of random data with ",
             mu,"=",m,", ",
             sigma^2,"=",s2,", ",
             "draws = ", numdraws,", ",
             bar(x),"=",xbar,", ",
             s^2,"=",sde),
             list(m=x_mean,xbar=mean(x),s2=x_sd^2,sde=var(x),numdraws=N)))

print(n)

Create a function with optional call variables

Powershell provides a lot of built-in support for common parameter scenarios, including mandatory parameters, optional parameters, "switch" (aka flag) parameters, and "parameter sets."

By default, all parameters are optional. The most basic approach is to simply check each one for $null, then implement whatever logic you want from there. This is basically what you have already shown in your sample code.

If you want to learn about all of the special support that Powershell can give you, check out these links:

about_Functions

about_Functions_Advanced

about_Functions_Advanced_Parameters

How do I stop Notepad++ from showing autocomplete for all words in the file

Notepad++ provides 2 types of features:

  • Auto-completion that read the open file and provide suggestion of words and/or functions within the file
  • Suggestion with the arguments of functions (specific to the language)

Based on what you write, it seems what you want is auto-completion on function only + suggestion on arguments.

To do that, you just need to change a setting.

  1. Go to Settings > Preferences... > Auto-completion
  2. Check Enable Auto-completion on each input
  3. Select Function completion and not Word completion
  4. Check Function parameter hint on input (if you have this option)

On version 6.5.5 of Notepad++, I have this setting settings

Some documentation about auto-completion is available in Notepad++ Wiki.

Write Array to Excel Range

This is an excerpt from method of mine, which converts a DataTable (the dt variable) into an array and then writes the array into a Range on a worksheet (wsh var). You can also change the topRow variable to whatever row you want the array of strings to be placed at.

object[,] arr = new object[dt.Rows.Count, dt.Columns.Count];
for (int r = 0; r < dt.Rows.Count; r++)
{
    DataRow dr = dt.Rows[r];
    for (int c = 0; c < dt.Columns.Count; c++)
    {
        arr[r, c] = dr[c];
    }
}
Excel.Range c1 = (Excel.Range)wsh.Cells[topRow, 1];
Excel.Range c2 = (Excel.Range)wsh.Cells[topRow + dt.Rows.Count - 1, dt.Columns.Count];
Excel.Range range = wsh.get_Range(c1, c2);
range.Value = arr;

Of course you do not need to use an intermediate DataTable like I did, the code excerpt is just to demonstrate how an array can be written to worksheet in single call.

Eclipse: Error ".. overlaps the location of another project.." when trying to create new project

I know this is older, but wanted to contribute another possibly solution.

If you want to keep the project location, as I did, I found that copying the .project file from another project into the project's directory, then editing the .project file to name it properly, then choosing the Import Existing Projects into Workspace option worked for me.

In Windows, I used a file monitor to see what Eclipse was doing, and it was simply erroring out for some unknown reason when trying to create the .project file. So, I did that manually and it worked for me.

Trying to embed newline in a variable in bash

there is no need to use for cycle

you can benefit from bash parameter expansion functions:

var="a b c"; 
var=${var// /\\n}; 
echo -e $var
a
b
c

or just use tr:

var="a b c"
echo $var | tr " " "\n"
a
b
c

AngularJS: Can't I set a variable value on ng-click?

You can use some thing like this

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
_x000D_
<head>_x000D_
  <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.26/angular.min.js"></script>_x000D_
</head>_x000D_
_x000D_
<body>_x000D_
  <div ng-app="" ng-init="btn1=false" ng-init="btn2=false">_x000D_
    <p>_x000D_
      <input type="submit" ng-disabled="btn1||btn2" ng-click="btn1=true" ng-model="btn1" />_x000D_
    </p>_x000D_
    <p>_x000D_
      <button ng-disabled="btn1||btn2" ng-model="btn2" ng-click="btn2=true">Click Me!</button>_x000D_
    </p>_x000D_
  </div>_x000D_
</body>_x000D_
_x000D_
</html>
_x000D_
_x000D_
_x000D_

SQLite "INSERT OR REPLACE INTO" vs. "UPDATE ... WHERE"

UPDATE will not do anything if the row does not exist.

Where as the INSERT OR REPLACE would insert if the row does not exist, or replace the values if it does.

How to remove the character at a given index from a string in C?

int chartoremove = 1;

strncpy(word2, word, chartoremove);
strncpy(((char*)word2)+chartoremove, ((char*)word)+chartoremove+1,
    strlen(word)-1-chartoremove);

Ugly as hell

Check which element has been clicked with jQuery

Use this, I think I can get your idea.

Live demo: http://jsfiddle.net/oscarj24/h722g/1/

$('body').click(function(e) {

    var target = $(e.target), article;

    if (target.is('#news_gallery li .over')) {
       article = $('#news-article .news-article');
    } else if (target.is('#work_gallery li .over')) {
       article = $('#work-article .work-article');
    } else if (target.is('#search-item li')) {
       article = $('#search-item .search-article');
    }

    if (article) {
       // Do Something
    }
});?

Get day of week in SQL Server 2005/2008

EUROPE:

declare @d datetime;
set @d=getdate();
set @dow=((datepart(dw,@d) + @@DATEFIRST-2) % 7+1);

What are the differences between if, else, and else if?

if (condition)
{
  thingsToDo()..
} 
else if (condition2)
{
  thingsToDoInTheSecondCase()..
}
else
{
  thingsToDoInOtherCase()..
}

Django, creating a custom 500/404 error page

From the page you referenced:

When you raise Http404 from within a view, Django will load a special view devoted to handling 404 errors. It finds it by looking for the variable handler404 in your root URLconf (and only in your root URLconf; setting handler404 anywhere else will have no effect), which is a string in Python dotted syntax – the same format the normal URLconf callbacks use. A 404 view itself has nothing special: It’s just a normal view.

So I believe you need to add something like this to your urls.py:

handler404 = 'views.my_404_view'

and similar for handler500.

How to receive POST data in django

You should have access to the POST dictionary on the request object.

Make an existing Git branch track a remote branch?

For Git versions 1.8.0 and higher:

Actually for the accepted answer to work:

git remote add upstream <remote-url>
git fetch upstream
git branch -f --track qa upstream/qa
# OR Git version 1.8.0 and higher:
git branch --set-upstream-to=upstream/qa
# Gitversions lower than 1.8.0
git branch --set-upstream qa upstream/qa

Equivalent of Math.Min & Math.Max for Dates?

How about:

public static T Min<T>(params T[] values)
{
    if (values == null) throw new ArgumentNullException("values");
    var comparer = Comparer<T>.Default;
    switch(values.Length) {
        case 0: throw new ArgumentException();
        case 1: return values[0];
        case 2: return comparer.Compare(values[0],values[1]) < 0
               ? values[0] : values[1];
        default:
            T best = values[0];
            for (int i = 1; i < values.Length; i++)
            {
                if (comparer.Compare(values[i], best) < 0)
                {
                    best = values[i];
                }
            }
            return best;
    }        
}
// overload for the common "2" case...
public static T Min<T>(T x, T y)
{
    return Comparer<T>.Default.Compare(x, y) < 0 ? x : y;
}

Works with any type that supports IComparable<T> or IComparable.

Actually, with LINQ, another alternative is:

var min = new[] {x,y,z}.Min();

Mocking Extension Methods with Moq

You can't "directly" mock static method (hence extension method) with mocking framework. You can try Moles (http://research.microsoft.com/en-us/projects/pex/downloads.aspx), a free tool from Microsoft that implements a different approach. Here is the description of the tool:

Moles is a lightweight framework for test stubs and detours in .NET that is based on delegates.

Moles may be used to detour any .NET method, including non-virtual/static methods in sealed types.

You can use Moles with any testing framework (it's independent about that).

Finding non-numeric rows in dataframe in pandas?

Already some great answers to this question, however here is a nice snippet that I use regularly to drop rows if they have non-numeric values on some columns:

# Eliminate invalid data from dataframe (see Example below for more context)

num_df = (df.drop(data_columns, axis=1)
         .join(df[data_columns].apply(pd.to_numeric, errors='coerce')))

num_df = num_df[num_df[data_columns].notnull().all(axis=1)]

The way this works is we first drop all the data_columns from the df, and then use a join to put them back in after passing them through pd.to_numeric (with option 'coerce', such that all non-numeric entries are converted to NaN). The result is saved to num_df.

On the second line we use a filter that keeps only rows where all values are not null.

Note that pd.to_numeric is coercing to NaN everything that cannot be converted to a numeric value, so strings that represent numeric values will not be removed. For example '1.25' will be recognized as the numeric value 1.25.

Disclaimer: pd.to_numeric was introduced in pandas version 0.17.0

Example:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({"item": ["a", "b", "c", "d", "e"],
   ...:                    "a": [1,2,3,"bad",5],
   ...:                    "b":[0.1,0.2,0.3,0.4,0.5]})

In [3]: df
Out[3]: 
     a    b item
0    1  0.1    a
1    2  0.2    b
2    3  0.3    c
3  bad  0.4    d
4    5  0.5    e

In [4]: data_columns = ['a', 'b']

In [5]: num_df = (df
   ...:           .drop(data_columns, axis=1)
   ...:           .join(df[data_columns].apply(pd.to_numeric, errors='coerce')))

In [6]: num_df
Out[6]: 
  item   a    b
0    a   1  0.1
1    b   2  0.2
2    c   3  0.3
3    d NaN  0.4
4    e   5  0.5

In [7]: num_df[num_df[data_columns].notnull().all(axis=1)]
Out[7]: 
  item  a    b
0    a  1  0.1
1    b  2  0.2
2    c  3  0.3
4    e  5  0.5

How to check whether a select box is empty using JQuery/Javascript

Another correct way to get selected value would be using this selector:

$("option[value="0"]:selected")

Best for you!

How to open a file / browse dialog using javascript?

Create input element.

Missing from these answers is how to get a file dialog without a input element on the page.

The function to show the input file dialog.

function openFileDialog (accept, callback) {  // this function must be called from  a user
                                              // activation event (ie an onclick event)
    
    // Create an input element
    var inputElement = document.createElement("input");

    // Set its type to file
    inputElement.type = "file";

    // Set accept to the file types you want the user to select. 
    // Include both the file extension and the mime type
    inputElement.accept = accept;

    // set onchange event to call callback when user has selected file
    inputElement.addEventListener("change", callback)
    
    // dispatch a click event to open the file dialog
    inputElement.dispatchEvent(new MouseEvent("click")); 
}

NOTE the function must be part of a user activation such as a click event. Attempting to open the file dialog without user activation will fail.

NOTE input.accept is not used in Edge

Example.

Calling above function when user clicks an anchor element.

_x000D_
_x000D_
// wait for window to load
window.addEventListener("load", windowLoad);

// open a dialog function
function openFileDialog (accept, multy = false, callback) { 
    var inputElement = document.createElement("input");
    inputElement.type = "file";
    inputElement.accept = accept; // Note Edge does not support this attribute
    if (multy) {
        inputElement.multiple = multy;
    }
    if (typeof callback === "function") {
         inputElement.addEventListener("change", callback);
    }
    inputElement.dispatchEvent(new MouseEvent("click")); 
}

// onload event
function windowLoad () {
    // add user click event to userbutton
    userButton.addEventListener("click", openDialogClick);
}

// userButton click event
function openDialogClick () {
    // open file dialog for text files
    openFileDialog(".txt,text/plain", true, fileDialogChanged);
}

// file dialog onchange event handler
function fileDialogChanged (event) {
    [...this.files].forEach(file => {
        var div = document.createElement("div");
        div.className = "fileList common";
        div.textContent = file.name;
        userSelectedFiles.appendChild(div);
    });
}
_x000D_
.common {
    font-family: sans-serif;
    padding: 2px;
    margin : 2px;
    border-radius: 4px;
 }
.fileList {
    background: #229;
    color: white;
}
#userButton {
    background: #999;
    color: #000;
    width: 8em;
    text-align: center;
    cursor: pointer;
}

#userButton:hover {
   background : #4A4;
   color : white;
}
_x000D_
<a id = "userButton" class = "common" title = "Click to open file selection dialog">Open file dialog</a>
<div id = "userSelectedFiles" class = "common"></div>
_x000D_
_x000D_
_x000D_

Warning the above snippet is written in ES6.

TypeError: 'NoneType' object is not iterable in Python

It means the value of data is None.

Simplest way to set image as JPanel background

As I know the way you can do it is to override paintComponent method that demands to inherit JPanel

 @Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g); // paint the background image and scale it to fill the entire space
    g.drawImage(/*....*/);
}

The other way (a bit complicated) to create second custom JPanel and put is as background for your main

ImagePanel

public class ImagePanel extends JPanel
{
private static final long serialVersionUID = 1L;
private Image image = null;
private int iWidth2;
private int iHeight2;

public ImagePanel(Image image)
{
    this.image = image;
    this.iWidth2 = image.getWidth(this)/2;
    this.iHeight2 = image.getHeight(this)/2;
}


public void paintComponent(Graphics g)
{
    super.paintComponent(g);
    if (image != null)
    {
        int x = this.getParent().getWidth()/2 - iWidth2;
        int y = this.getParent().getHeight()/2 - iHeight2;
        g.drawImage(image,x,y,this);
    }
}
}

EmptyPanel

public class EmptyPanel extends JPanel{

private static final long serialVersionUID = 1L;

public EmptyPanel() {
    super();
    init();
}

@Override
public boolean isOptimizedDrawingEnabled() {
    return false;
}


public void init(){

    LayoutManager overlay = new OverlayLayout(this);
    this.setLayout(overlay);

    ImagePanel iPanel = new ImagePanel(new IconToImage(IconFactory.BG_CENTER).getImage());
    iPanel.setLayout(new BorderLayout());   
    this.add(iPanel);
    iPanel.setOpaque(false);                
}
}

IconToImage

public class IconToImage {

Icon icon;
Image image;


public IconToImage(Icon icon) {
    this.icon = icon;
    image = iconToImage();
}

public Image iconToImage() { 
    if (icon instanceof ImageIcon) { 
        return ((ImageIcon)icon).getImage(); 
    } else { 
        int w = icon.getIconWidth(); 
        int h = icon.getIconHeight(); 
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); 
        GraphicsDevice gd = ge.getDefaultScreenDevice(); 
        GraphicsConfiguration gc = gd.getDefaultConfiguration(); 
        BufferedImage image = gc.createCompatibleImage(w, h); 
        Graphics2D g = image.createGraphics(); 
        icon.paintIcon(null, g, 0, 0); 
        g.dispose(); 
        return image; 
    } 
}


/**
 * @return the image
 */
public Image getImage() {
    return image;
}
}

Android Studio - UNEXPECTED TOP-LEVEL EXCEPTION:

Suddenly, without any major change in my project, I too got this error.

All the above did not work for me, since I needed both the support libs V4 and V7.

At the end, because 2 hours ago the project compiled with no problems, I simply told Android Studio to REBUILD the project, and the error was gone.

Should a RESTful 'PUT' operation return something

As opposed to most of the answers here, I actually think that PUT should return the updated resource (in addition to the HTTP code of course).

The reason why you would want to return the resource as a response for PUT operation is because when you send a resource representation to the server, the server can also apply some processing to this resource, so the client would like to know how does this resource look like after the request completed successfully. (otherwise it will have to issue another GET request).

Capture the Screen into a Bitmap

If using the .NET 2.0 (or later) framework you can use the CopyFromScreen() method detailed here:

http://www.geekpedia.com/tutorial181_Capturing-screenshots-using-Csharp.html

//Create a new bitmap.
var bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width,
                               Screen.PrimaryScreen.Bounds.Height,
                               PixelFormat.Format32bppArgb);

// Create a graphics object from the bitmap.
var gfxScreenshot = Graphics.FromImage(bmpScreenshot);

// Take the screenshot from the upper left corner to the right bottom corner.
gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X,
                            Screen.PrimaryScreen.Bounds.Y,
                            0,
                            0,
                            Screen.PrimaryScreen.Bounds.Size,
                            CopyPixelOperation.SourceCopy);

// Save the screenshot to the specified path that the user has chosen.
bmpScreenshot.Save("Screenshot.png", ImageFormat.Png);

How to set the maximum memory usage for JVM?

If you want to limit memory for jvm (not the heap size ) ulimit -v

To get an idea of the difference between jvm and heap memory , take a look at this excellent article http://blogs.vmware.com/apps/2011/06/taking-a-closer-look-at-sizing-the-java-process.html

C string append

do the following:

strcat(new_str,str1);
strcat(new_str,str2);

SQL Server database restore error: specified cast is not valid. (SqlManagerUI)

The GUI can be fickle at times. The error you got when using T-SQL is because you're trying to overwrite an existing database, but did not specify to overwrite/replace the existing database. The following might work:

Use Master
Go
RESTORE DATABASE Publications
  FROM DISK = 'C:\Publications_backup_2012_10_15_010004_5648316.bak'
  WITH 
    MOVE 'Publications' TO 'C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS2008R2\MSSQL\DATA\Publications.mdf',--adjust path
    MOVE 'Publications_log' TO 'C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS2008R2\MSSQL\DATA\Publications.ldf'
, REPLACE -- Add REPLACE to specify the existing database which should be overwritten.

List<Map<String, String>> vs List<? extends Map<String, String>>

As you mentioned, there could be two below versions of defining a List:

  1. List<? extends Map<String, String>>
  2. List<?>

2 is very open. It can hold any object type. This may not be useful in case you want to have a map of a given type. In case someone accidentally puts a different type of map, for example, Map<String, int>. Your consumer method might break.

In order to ensure that List can hold objects of a given type, Java generics introduced ? extends. So in #1, the List can hold any object which is derived from Map<String, String> type. Adding any other type of data would throw an exception.

git diff between two different files

If you are using tortoise git you can right-click on a file and git a diff by: Right-clicking on the first file and through the tortoisegit submenu select "Diff later" Then on the second file you can also right-click on this, go to the tortoisegit submenu and then select "Diff with yourfilenamehere.txt"

Oracle SQL - DATE greater than statement

You need to convert the string to date using the to_date() function

SELECT * FROM OrderArchive
WHERE OrderDate <= to_date('31-Dec-2014','DD-MON-YYYY');

OR

SELECT * FROM OrderArchive
WHERE OrderDate <= to_date('31 Dec 2014','DD MON YYYY');

OR

SELECT * FROM OrderArchive
WHERE OrderDate <= to_date('2014-12-31','yyyy-MM-dd');

This will work only if OrderDate is stored in Date format. If it is Varchar you should apply to_date() func on that column also like

 SELECT * FROM OrderArchive
    WHERE to_date(OrderDate,'yyyy-Mm-dd') <= to_date('2014-12-31','yyyy-MM-dd');

npm WARN ... requires a peer of ... but none is installed. You must install peer dependencies yourself

You need to only depend on one major version of angular, so update all modules depending on angular 2.x :

  • update @angular/flex-layout to ^2.0.0-beta.9
  • update @angular/material to ^2.0.0-beta.12
  • update angularfire2 to ^4.0.0-rc.2
  • update zone.js to ^0.8.18
  • update webpack to ^3.8.1
  • add @angular/[email protected] (required for @angular/material)
  • replace angular2-google-maps by @agm/[email protected] (new name)

How to obtain the number of CPUs/cores in Linux from the command line?

The most portable solution I have found is the getconf command:

getconf _NPROCESSORS_ONLN

This works on both Linux and Mac OS X. Another benefit of this over some of the other approaches is that getconf has been around for a long time. Some of the older Linux machines I have to do development on don't have the nproc or lscpu commands available, but they have getconf.

Editor's note: While the getconf utility is POSIX-mandated, the specific _NPROCESSORS_ONLN and _NPROCESSORS_CONF values are not. That said, as stated, they work on Linux platforms as well as on macOS; on FreeBSD/PC-BSD, you must omit the leading _.

How to set scope property with ng-init?

Try this Code

var app = angular.module('myapp', []);
  app.controller('testController', function ($scope, $http) {
       $scope.init = function(){           
       alert($scope.testInput);
   };});

_x000D_
_x000D_
<body ng-app="myapp">_x000D_
      <div ng-controller='testController' data-ng-init="testInput='value'; init();" class="col-sm-9 col-lg-9" >_x000D_
      </div>_x000D_
</body>
_x000D_
_x000D_
_x000D_

Curl error: Operation timed out

Your curl gets timed out. Probably the url you are trying that requires more that 30 seconds.

If you are running the script through browser, then set the set_time_limit to zero for infinite seconds.

set_time_limit(0);

Increase the curl's operation time limit using this option CURLOPT_TIMEOUT

curl_setopt($ch, CURLOPT_TIMEOUT,500); // 500 seconds

It can also happen for infinite redirection from the server. To halt this try to run the script with follow location disabled.

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);

Best way to check if a URL is valid

Another way to check if given URL is valid is to try to access it, below function will fetch the headers from given URL, this will ensure that URL is valid AND web server is alive:

function is_url($url){
        $response = array();
        //Check if URL is empty
        if(!empty($url)) {
            $response = get_headers($url);
        }
        return (bool)in_array("HTTP/1.1 200 OK", $response, true);
/*Array
(
    [0] => HTTP/1.1 200 OK 
    [Date] => Sat, 29 May 2004 12:28:14 GMT
    [Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)
    [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
    [ETag] => "3f80f-1b6-3e1cb03b"
    [Accept-Ranges] => bytes
    [Content-Length] => 438
    [Connection] => close
    [Content-Type] => text/html
)*/ 
    }   

exceeds the list view threshold 5000 items in Sharepoint 2010

SharePoint lists V: Techniques for managing large lists :

Tutorial By Microsoft

Level: Advanced

Length: 40 - 50 minutes

When a SharePoint list gets large, you might see warnings such as, “This list exceeds the list view threshold,” or “Displaying the newest results below.” Find out why these warnings occur, and learn ways to configure your large list so that it still provides useful information.

After completing this course you will be able to:

  • Learn what the List View Threshold is, and understand its benefits.
  • Create an index so that you can see more information in a view.
  • Create folders to better organize your large list.
  • Use Datasheet view for fast filtering and sorting of a large list.
  • Learn what the Daily Time Window for Large Queries is.
  • Use Key Filters for fast filtering within Standard view.
  • Sync a large list to SharePoint Workspace.
  • Export a large list to Excel. Link a large list in Access.

Set colspan dynamically with jquery

I've also found that if you had display:none, then programmatically changed it to be visible, you might also have to set

$tr.css({display:'table-row'});

rather than display:inline or display:block otherwise the cell might only show as taking up 1 cell, no matter how large you have the colspan set to.

XAMPP - Port 80 in use by "Unable to open process" with PID 4! 12

Another very easy option is to simply set Apache to listen on a different port. This can be done by clicking on the "Config" button on the same line as the "Apache" module, select the "httpd.conf" file in the dropdown, then change the "Listen 80" line to "Listen 8080". Save the file and close it.

Now it avoids Port 80 and uses Port 8080 instead without issue. The only additional thing you need to do is make sure to put localhost:8080 in the browser so the browser knows to look on Port 8080. Otherwise it defaults to Port 80 and won't find your local site.

This will also require you to restart Apache for the change to take effect.

Voila! Fixed.

How to run a command in the background on Windows?

I believe the command you are looking for is start /b *command*

For unix, nohup represents 'no hangup', which is slightly different than a background job (which would be *command* &. I believe that the above command should be similar to a background job for windows.

Simplest way to do grouped barplot

with ggplot2:

library(ggplot2)
Animals <- read.table(
  header=TRUE, text='Category        Reason Species
1   Decline       Genuine      24
2  Improved       Genuine      16
3  Improved Misclassified      85
4   Decline Misclassified      41
5   Decline     Taxonomic       2
6  Improved     Taxonomic       7
7   Decline       Unclear      41
8  Improved       Unclear     117')

ggplot(Animals, aes(factor(Reason), Species, fill = Category)) + 
  geom_bar(stat="identity", position = "dodge") + 
  scale_fill_brewer(palette = "Set1")

Bar Chart

how to parse JSON file with GSON

In case you need to parse it from a file, I find the best solution to use a HashMap<String, String> to use it inside your java code for better manipultion.

Try out this code:

public HashMap<String, String> myMethodName() throws FileNotFoundException
{
    String path = "absolute path to your file";
    BufferedReader bufferedReader = new BufferedReader(new FileReader(path));

    Gson gson = new Gson();
    HashMap<String, String> json = gson.fromJson(bufferedReader, HashMap.class);
    return json;
}

Angular 2: Can't bind to 'ngModel' since it isn't a known property of 'input'

I encountered a similar error after upgrading to RC5; i.e. Angular 2: Can't bind to 'ngModel' since it isn't a known property of 'input'.

The code on Plunker show you using Angular2 RC4, but the example code at https://angular.io/docs/ts/latest/cookbook/dynamic-form.html is using NGModule which is part of RC5. NGModules is a breaking change from RC4 to RC5.

This page explains the migration from RC4 to RC5: https://angular.io/docs/ts/latest/cookbook/rc4-to-rc5.html

I hope this addresses the error you're getting and help get you going in the right direction.

In short, I had to create an NGModule in app.module.ts:

import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule }   from '@angular/forms';

import { AppComponent }  from './app.component';

@NgModule({
    imports:      [ BrowserModule, FormsModule ],
    declarations: [ AppComponent ],
    bootstrap:    [ AppComponent ]
})
export class AppModule { }

I then changed main.ts to use the module:

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppModule } from './app.module';

platformBrowserDynamic().bootstrapModule(AppModule);

Of course, I also needed to update the dependencies in package.json. Here's my dependencies from package.json. Admittedly, I've hobbled them together from other sources (maybe the ng docs examples), so your mileage may vary:

...
"dependencies": {
    "@angular/common": "2.0.0-rc.5",
    "@angular/compiler": "2.0.0-rc.5",
    "@angular/core": "2.0.0-rc.5",
    "@angular/forms": "0.3.0",
    "@angular/http": "2.0.0-rc.5",
    "@angular/platform-browser": "2.0.0-rc.5",
    "@angular/platform-browser-dynamic": "2.0.0-rc.5",
    "@angular/router": "3.0.0-rc.1",
    "@angular/router-deprecated": "2.0.0-rc.2",
    "@angular/upgrade": "2.0.0-rc.5",
    "systemjs": "0.19.27",
    "core-js": "^2.4.0",
    "reflect-metadata": "^0.1.3",
    "rxjs": "5.0.0-beta.6",
    "zone.js": "^0.6.12",
    "angular2-in-memory-web-api": "0.0.15",
    "bootstrap": "^3.3.6"
  },
...

I hope this helps better. :-)

How to format LocalDate to string?

A pretty nice way to do this is to use SimpleDateFormat I'll show you how:

SimpleDateFormat sdf = new SimpleDateFormat("d MMMM YYYY");
Date d = new Date();
sdf.format(d);

I see that you have the date in a variable:

sdf.format(variable_name);

Cheers.

C++ Array Of Pointers

I would do it something along these lines:

class Foo{
...
};

int main(){
  Foo* arrayOfFoo[100]; //[1]

  arrayOfFoo[0] = new Foo; //[2]
}

[1] This makes an array of 100 pointers to Foo-objects. But no Foo-objects are actually created.

[2] This is one possible way to instantiate an object, and at the same time save a pointer to this object in the first position of your array.

is there a function in lodash to replace matched item

If you're looking for a way to immutably change the collection (as I was when I found your question), you might take a look at immutability-helper, a library forked from the original React util. In your case, you would accomplish what you mentioned via the following:

var update = require('immutability-helper')
var arr = [{id: 1, name: "Person 1"}, {id:2, name:"Person 2"}]
var newArray = update(arr, { 0: { name: { $set: 'New Name' } } })
//=> [{id: 1, name: "New Name"}, {id:2, name:"Person 2"}]

Java correct way convert/cast object to Double

You can use the instanceof operator to test to see if it is a double prior to casting. You can then safely cast it to a double. In addition you can test it against other known types (e.g. Integer) and then coerce them into a double manually if desired.

    Double d = null;
    if (obj instanceof Double) {
        d = (Double) obj;
    }

How do you round to 1 decimal place in Javascript?

Why not just

let myNumber = 213.27321;
+myNumber.toFixed(1); // => 213.3
  1. toFixed: returns a string representing the given number using fixed-point notation.
  2. Unary plus (+): The unary plus operator precedes its operand and evaluates to its operand but attempts to convert it into a number, if it isn't already.

Do Facebook Oauth 2.0 Access Tokens Expire?

Yes, they do expire. There is an 'expires' value that is passed along with the 'access_token', and from what I can tell it's about 2 hours. I've been searching, but I don't see a way to request a longer expiration time.

How can you get the active users connected to a postgreSQL database via SQL?

(question) Don't you get that info in

select * from pg_user;

or using the view pg_stat_activity:

select * from pg_stat_activity;

Added:

the view says:

One row per server process, showing database OID, database name, process ID, user OID, user name, current query, query's waiting status, time at which the current query began execution, time at which the process was started, and client's address and port number. The columns that report data on the current query are available unless the parameter stats_command_string has been turned off. Furthermore, these columns are only visible if the user examining the view is a superuser or the same as the user owning the process being reported on.

can't you filter and get that information? that will be the current users on the Database, you can use began execution time to get all queries from last 5 minutes for example...

something like that.

How to perform runtime type checking in Dart?

object.runtimeType returns the type of object

For example:

print("HELLO".runtimeType); //prints String
var x=0.0;
print(x.runtimeType); //prints double

Get $_POST from multiple checkboxes

Edit To reflect what @Marc said in the comment below.

You can do a loop through all the posted values.

HTML:

<input type="checkbox" name="check_list[]" value="<?=$rowid?>" />
<input type="checkbox" name="check_list[]" value="<?=$rowid?>" />
<input type="checkbox" name="check_list[]" value="<?=$rowid?>" />

PHP:

foreach($_POST['check_list'] as $item){
  // query to delete where item = $item
}

Reload activity in Android

i used this and it works fine without finish()

startActivity(getIntent());

How to dynamically remove items from ListView on a button click?

adapter.remove(arraylist.get(position));
adapter.notifyDataSetChanged();

or you can call again

setListAdapter(adapter)

Insert string in beginning of another string

The first case is done using the insert() method:

_sb.insert(0, "Hello ");

The latter case can be done using the overloaded + operator on Strings. This uses a StringBuilder behind the scenes:

String s2 = "Hello " + _s;

Convert audio files to mp3 using ffmpeg

You could use this command:

ffmpeg -i input.wav -vn -ar 44100 -ac 2 -b:a 192k output.mp3

Explanation of the used arguments in this example:

  • -i - input file

  • -vn - Disable video, to make sure no video (including album cover image) is included if the source would be a video file

  • -ar - Set the audio sampling frequency. For output streams it is set by default to the frequency of the corresponding input stream. For input streams this option only makes sense for audio grabbing devices and raw demuxers and is mapped to the corresponding demuxer options.

  • -ac - Set the number of audio channels. For output streams it is set by default to the number of input audio channels. For input streams this option only makes sense for audio grabbing devices and raw demuxers and is mapped to the corresponding demuxer options. So used here to make sure it is stereo (2 channels)

  • -b:a - Converts the audio bitrate to be exact 192kbit per second

How to implement private method in ES6 class with Traceur

You can always use normal functions:

function myPrivateFunction() {
  console.log("My property: " + this.prop);
}

class MyClass() {
  constructor() {
    this.prop = "myProp";
    myPrivateFunction.bind(this)();
  }
}

new MyClass(); // 'My property: myProp'

Regex matching beginning AND end strings

Scanner scanner = new Scanner(System.in);
String part = scanner.nextLine();
String line = scanner.nextLine();

String temp = "\\b" + part +"|"+ part + "\\b";
Pattern pattern = Pattern.compile(temp.toLowerCase());
Matcher matcher = pattern.matcher(line.toLowerCase());

System.out.println(matcher.find() ? "YES":"NO");

If you need to determine if any of the words of this text start or end with the sequence. you can use this regex \bsubstring|substring\b anythingsubstring substringanything anythingsubstringanything

How to validate domain name in PHP?

Your regular expression is fine, but you're not using preg_match right. It returns an int (0 or 1), not a boolean. Just write if(!preg_match($regex, $string)) { ... }

Pointers in JavaScript?

Late answer but I have come across a way of passing primitive values by reference by means of closures. It is rather complicated to create a pointer, but it works.

function ptr(get, set) {
    return { get: get, set: set };
}

function helloWorld(namePtr) {
    console.log(namePtr.get());
    namePtr.set('jack');
    console.log(namePtr.get())
}

var myName = 'joe';
var myNamePtr = ptr(
    function () { return myName; },
    function (value) { myName = value; }
);

helloWorld(myNamePtr); // joe, jack
console.log(myName); // jack

In ES6, the code can be shortened to use lambda expressions:

var myName = 'joe';
var myNamePtr = ptr(=> myName, v => myName = v);

helloWorld(myNamePtr); // joe, jack
console.log(myName); // jack

Can you get the column names from a SqlDataReader?

var reader = cmd.ExecuteReader();

var columns = new List<string>();

for(int i=0;i<reader.FieldCount;i++)
{
   columns.Add(reader.GetName(i));
}

or

var columns = Enumerable.Range(0, reader.FieldCount).Select(reader.GetName).ToList();

AngularJS : Difference between the $observe and $watch methods

If I understand your question right you are asking what is difference if you register listener callback with $watch or if you do it with $observe.

Callback registerd with $watch is fired when $digest is executed.

Callback registered with $observe are called when value changes of attributes that contain interpolation (e.g. attr="{{notJetInterpolated}}").


Inside directive you can use both of them on very similar way:

    attrs.$observe('attrYouWatch', function() {
         // body
    });

or

    scope.$watch(attrs['attrYouWatch'], function() {
         // body
    });

Java RegEx meta character (.) and ordinary dot?

If you want the dot or other characters with a special meaning in regexes to be a normal character, you have to escape it with a backslash. Since regexes in Java are normal Java strings, you need to escape the backslash itself, so you need two backslashes e.g. \\.

Changing the current working directory in Java?

It is possible to change the PWD, using JNA/JNI to make calls to libc. The JRuby guys have a handy java library for making POSIX calls called jna-posix Here's the maven info

You can see an example of its use here (Clojure code, sorry). Look at the function chdirToRoot

Create an empty data.frame

If you want to create an empty data.frame with dynamic names (colnames in a variable), this can help:

names <- c("v","u","w")
df <- data.frame()
for (k in names) df[[k]]<-as.numeric()

You can change the types as well if you need so. like:

names <- c("u", "v")
df <- data.frame()
df[[names[1]]] <- as.numeric()
df[[names[2]]] <- as.character()

How to suppress "error TS2533: Object is possibly 'null' or 'undefined'"?

If you know from external means that an expression is not null or undefined, you can use the non-null assertion operator ! to coerce away those types:

// Error, some.expr may be null or undefined
let x = some.expr.thing;
// OK
let y = some.expr!.thing;

What's the best way to convert a number to a string in JavaScript?

It seems similar results when using node.js. I ran this script:

let bar;
let foo = ["45","foo"];

console.time('string concat testing');
for (let i = 0; i < 10000000; i++) {
    bar = "" + foo;
}
console.timeEnd('string concat testing');


console.time("string obj testing");
for (let i = 0; i < 10000000; i++) {
    bar = String(foo);
}
console.timeEnd("string obj testing");

console.time("string both");
for (let i = 0; i < 10000000; i++) {
    bar = "" + foo + "";
}
console.timeEnd("string both");

and got the following results:

? node testing.js
string concat testing: 2802.542ms
string obj testing: 3374.530ms
string both: 2660.023ms

Similar times each time I ran it.

Why Choose Struct Over Class?

Since struct instances are allocated on stack, and class instances are allocated on heap, structs can sometimes be drastically faster.

However, you should always measure it yourself and decide based on your unique use case.

Consider the following example, which demonstrates 2 strategies of wrapping Int data type using struct and class. I am using 10 repeated values are to better reflect real world, where you have multiple fields.

class Int10Class {
    let value1, value2, value3, value4, value5, value6, value7, value8, value9, value10: Int
    init(_ val: Int) {
        self.value1 = val
        self.value2 = val
        self.value3 = val
        self.value4 = val
        self.value5 = val
        self.value6 = val
        self.value7 = val
        self.value8 = val
        self.value9 = val
        self.value10 = val
    }
}

struct Int10Struct {
    let value1, value2, value3, value4, value5, value6, value7, value8, value9, value10: Int
    init(_ val: Int) {
        self.value1 = val
        self.value2 = val
        self.value3 = val
        self.value4 = val
        self.value5 = val
        self.value6 = val
        self.value7 = val
        self.value8 = val
        self.value9 = val
        self.value10 = val
    }
}

func + (x: Int10Class, y: Int10Class) -> Int10Class {
    return IntClass(x.value + y.value)
}

func + (x: Int10Struct, y: Int10Struct) -> Int10Struct {
    return IntStruct(x.value + y.value)
}

Performance is measured using

// Measure Int10Class
measure("class (10 fields)") {
    var x = Int10Class(0)
    for _ in 1...10000000 {
        x = x + Int10Class(1)
    }
}

// Measure Int10Struct
measure("struct (10 fields)") {
    var y = Int10Struct(0)
    for _ in 1...10000000 {
        y = y + Int10Struct(1)
    }
}

func measure(name: String, @noescape block: () -> ()) {
    let t0 = CACurrentMediaTime()

    block()

    let dt = CACurrentMediaTime() - t0
    print("\(name) -> \(dt)")
}

Code can be found at https://github.com/knguyen2708/StructVsClassPerformance

UPDATE (27 Mar 2018):

As of Swift 4.0, Xcode 9.2, running Release build on iPhone 6S, iOS 11.2.6, Swift Compiler setting is -O -whole-module-optimization:

  • class version took 2.06 seconds
  • struct version took 4.17e-08 seconds (50,000,000 times faster)

(I no longer average multiple runs, as variances are very small, under 5%)

Note: the difference is a lot less dramatic without whole module optimization. I'd be glad if someone can point out what the flag actually does.


UPDATE (7 May 2016):

As of Swift 2.2.1, Xcode 7.3, running Release build on iPhone 6S, iOS 9.3.1, averaged over 5 runs, Swift Compiler setting is -O -whole-module-optimization:

  • class version took 2.159942142s
  • struct version took 5.83E-08s (37,000,000 times faster)

Note: as someone mentioned that in real-world scenarios, there will be likely more than 1 field in a struct, I have added tests for structs/classes with 10 fields instead of 1. Surprisingly, results don't vary much.


ORIGINAL RESULTS (1 June 2014):

(Ran on struct/class with 1 field, not 10)

As of Swift 1.2, Xcode 6.3.2, running Release build on iPhone 5S, iOS 8.3, averaged over 5 runs

  • class version took 9.788332333s
  • struct version took 0.010532942s (900 times faster)

OLD RESULTS (from unknown time)

(Ran on struct/class with 1 field, not 10)

With release build on my MacBook Pro:

  • The class version took 1.10082 sec
  • The struct version took 0.02324 sec (50 times faster)

Nested JSON: How to add (push) new items to an object?

You can achieve this using Lodash _.assign function.

library[title] = _.assign({}, {'foregrounds': foregrounds }, {'backgrounds': backgrounds });

_x000D_
_x000D_
// This is my JSON object generated from a database_x000D_
var library = {_x000D_
  "Gold Rush": {_x000D_
    "foregrounds": ["Slide 1", "Slide 2", "Slide 3"],_x000D_
    "backgrounds": ["1.jpg", "", "2.jpg"]_x000D_
  },_x000D_
  "California": {_x000D_
    "foregrounds": ["Slide 1", "Slide 2", "Slide 3"],_x000D_
    "backgrounds": ["3.jpg", "4.jpg", "5.jpg"]_x000D_
  }_x000D_
}_x000D_
_x000D_
// These will be dynamically generated vars from editor_x000D_
var title = "Gold Rush";_x000D_
var foregrounds = ["Howdy", "Slide 2"];_x000D_
var backgrounds = ["1.jpg", ""];_x000D_
_x000D_
function save() {_x000D_
_x000D_
  // If title already exists, modify item_x000D_
  if (library[title]) {_x000D_
_x000D_
    // override one Object with the values of another (lodash)_x000D_
    library[title] = _.assign({}, {_x000D_
      'foregrounds': foregrounds_x000D_
    }, {_x000D_
      'backgrounds': backgrounds_x000D_
    });_x000D_
    console.log(library[title]);_x000D_
_x000D_
    // Save to Database. Then on callback..._x000D_
    // console.log('Changes Saved to <b>' + title + '</b>');_x000D_
  }_x000D_
_x000D_
  // If title does not exist, add new item_x000D_
  else {_x000D_
    // Format it for the JSON object_x000D_
    var item = ('"' + title + '" : {"foregrounds" : ' + foregrounds + ',"backgrounds" : ' + backgrounds + '}');_x000D_
_x000D_
    // THE PROBLEM SEEMS TO BE HERE??_x000D_
    // Error: "Result of expression 'library.push' [undefined] is not a function"_x000D_
    library.push(item);_x000D_
_x000D_
    // Save to Database. Then on callback..._x000D_
    console.log('Added: <b>' + title + '</b>');_x000D_
  }_x000D_
}_x000D_
_x000D_
save();
_x000D_
<script src="https://cdn.jsdelivr.net/npm/[email protected]/lodash.min.js"></script>
_x000D_
_x000D_
_x000D_

How to add header data in XMLHttpRequest when using formdata?

Your error

InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable

appears because you must call setRequestHeader after calling open. Simply move your setRequestHeader line below your open line (but before send):

xmlhttp.open("POST", url);
xmlhttp.setRequestHeader("x-filename", photoId);
xmlhttp.send(formData);

How to increase Heap size of JVM

Following are few options available to change Heap Size.

-Xms<size>        set initial Java heap size
-Xmx<size>        set maximum Java heap size
-Xss<size>        set java thread stack size


java -Xmx256m TestData.java

How to implement custom JsonConverter in JSON.NET to deserialize a List of base class objects?

Here's another solution that avoids the use of jObject.CreateReader(), and instead creates a new JsonTextReader (which is the behavior used by the default JsonCreate.Deserialze method:

public abstract class JsonCreationConverter<T> : JsonConverter
{
    protected abstract T Create(Type objectType, JObject jObject);

    public override bool CanConvert(Type objectType)
    {
        return typeof(T).IsAssignableFrom(objectType);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        if (reader.TokenType == JsonToken.Null)
            return null;

        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        T target = Create(objectType, jObject);

        // Populate the object properties
        StringWriter writer = new StringWriter();
        serializer.Serialize(writer, jObject);
        using (JsonTextReader newReader = new JsonTextReader(new StringReader(writer.ToString())))
        { 
            newReader.Culture = reader.Culture;
            newReader.DateParseHandling = reader.DateParseHandling;
            newReader.DateTimeZoneHandling = reader.DateTimeZoneHandling;
            newReader.FloatParseHandling = reader.FloatParseHandling;
            serializer.Populate(newReader, target);
        }

        return target;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value);
    }
}

Why am I seeing "TypeError: string indices must be integers"?

item is most likely a string in your code; the string indices are the ones in the square brackets, e.g., gravatar_id. So I'd first check your data variable to see what you received there; I guess that data is a list of strings (or at least a list containing at least one string) while it should be a list of dictionaries.

Why does ENOENT mean "No such file or directory"?

It's simply “No such directory entry”. Since directory entries can be directories or files (or symlinks, or sockets, or pipes, or devices), the name ENOFILE would have been too narrow in its meaning.

Why are my PowerShell scripts not running?

On Windows 10: Click change security property of myfile.ps1 and change "allow access" by right click / properties on myfile.ps1

VS2010 How to include files in project, to copy them to build output directory automatically during build or publish

  1. Add the file to your project.
  2. Go to the Properties of that file.
  3. Set "Build Action" to Embedded Resource.
  4. Set "Copy to Output Directory" to Copy Always.

Android - Get value from HashMap

Iterator myVeryOwnIterator = meMap.keySet().iterator();
while(myVeryOwnIterator.hasNext()) {
    String key=(String)myVeryOwnIterator.next();
    String value=(String)meMap.get(key);
    Toast.makeText(ctx, "Key: "+key+" Value: "+value, Toast.LENGTH_LONG).show();
}

Find running median from a stream of integers

There are a number of different solutions for finding running median from streamed data, I will briefly talk about them at the very end of the answer.

The question is about the details of the a specific solution (max heap/min heap solution), and how heap based solution works is explained below:

For the first two elements add smaller one to the maxHeap on the left, and bigger one to the minHeap on the right. Then process stream data one by one,

Step 1: Add next item to one of the heaps

   if next item is smaller than maxHeap root add it to maxHeap,
   else add it to minHeap

Step 2: Balance the heaps (after this step heaps will be either balanced or
   one of them will contain 1 more item)

   if number of elements in one of the heaps is greater than the other by
   more than 1, remove the root element from the one containing more elements and
   add to the other one

Then at any given time you can calculate median like this:

   If the heaps contain equal amount of elements;
     median = (root of maxHeap + root of minHeap)/2
   Else
     median = root of the heap with more elements

Now I will talk about the problem in general as promised in the beginning of the answer. Finding running median from a stream of data is a tough problem, and finding an exact solution with memory constraints efficiently is probably impossible for the general case. On the other hand, if the data has some characteristics we can exploit, we can develop efficient specialized solutions. For example, if we know that the data is an integral type, then we can use counting sort, which can give you a constant memory constant time algorithm. Heap based solution is a more general solution because it can be used for other data types (doubles) as well. And finally, if the exact median is not required and an approximation is enough, you can just try to estimate a probability density function for the data and estimate median using that.

a page can have only one server-side form tag

I think you did like this:

<asp:Content ID="Content2" ContentPlaceHolderID="MasterContent" runat="server">
  <form id="form1" runat="server">

 </form>
</asp:Content>

The form tag isn't needed. because you already have the same tag in the master page.

So you just remove that and it should be working.

IIS7 Permissions Overview - ApplicationPoolIdentity

Top Answer from Jon Adams

Here is how to implement this for the PowerShell folks

$IncommingPath = "F:\WebContent"
$Acl = Get-Acl $IncommingPath
$Ar = New-Object  system.security.accesscontrol.filesystemaccessrule("IIS AppPool\DefaultAppPool","FullControl","ContainerInherit, ObjectInherit", "None", "Allow")
$Acl.SetAccessRule($Ar)
Set-Acl $IncommingPath $Acl

How do I get the domain originating the request in express.js?

Instead of:

var host = req.get('host');
var origin = req.get('origin');

you can also use:

var host = req.headers.host;
var origin = req.headers.origin;

What do parentheses surrounding an object/function/class declaration mean?

The first parentheses are for, if you will, order of operations. The 'result' of the set of parentheses surrounding the function definition is the function itself which, indeed, the second set of parentheses executes.

As to why it's useful, I'm not enough of a JavaScript wizard to have any idea. :P

In oracle, how do I change my session to display UTF8?

The character set is part of the locale, which is determined by the value of NLS_LANG. As the documentation makes clear this is an operating system variable:

NLS_LANG is set as an environment variable on UNIX platforms. NLS_LANG is set in the registry on Windows platforms.

Now we can use ALTER SESSION to change the values for a couple of locale elements, NLS_LANGUAGE and NLS_TERRITORY. But not, alas, the character set. The reason for this discrepancy is - I think - that the language and territory simply effect how Oracle interprets the stored data, e.g. whether to display a comma or a period when displaying a large number. Wheareas the character set is concerned with how the client application renders the displayed data. This information is picked up by the client application at startup time, and cannot be changed from within.

How do I flush the PRINT buffer in TSQL?

Another better option is to not depend on PRINT or RAISERROR and just load your "print" statements into a ##Temp table in TempDB or a permanent table in your database which will give you visibility to the data immediately via a SELECT statement from another window. This works the best for me. Using a permanent table then also serves as a log to what happened in the past. The print statements are handy for errors, but using the log table you can also determine the exact point of failure based on the last logged value for that particular execution (assuming you track the overall execution start time in your log table.)