Programs & Examples On #Reverse geocoding

Generates an address from a latitude and longitude.

Android: Reverse geocoding - getFromLocation

It looks like there's two things happening here.

1) You've missed the new keyword from before calling the constructor.

2) The parameter you're passing in to the Geocoder constructor is incorrect. You're passing in a Locale where it's expecting a Context.

There are two Geocoder constructors, both of which require a Context, and one also taking a Locale:

Geocoder(Context context, Locale locale)
Geocoder(Context context)

Solution

Modify your code to pass in a valid Context and include new and you should be good to go.

Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());   
List<Address> myList = myLocation.getFromLocation(latPoint, lngPoint, 1);

Note

If you're still having problems it may be a permissioning issue. Geocoding implicitly uses the Internet to perform the lookups, so your application will require an INTERNET uses-permission tag in your manifest.

Add the following uses-permission node within the manifest node of your manifest.

<uses-permission android:name="android.permission.INTERNET" />

How to get city name from latitude and longitude coordinates in Google Maps?

Try this

var geocoder;
geocoder = new google.maps.Geocoder();
var latlng = new google.maps.LatLng(latitude, longitude);

geocoder.geocode(
{'latLng': latlng}, 
function(results, status) {
    if (status == google.maps.GeocoderStatus.OK) {
            if (results[0]) {
                var add= results[0].formatted_address ;
                var  value=add.split(",");

                count=value.length;
                country=value[count-1];
                state=value[count-2];
                city=value[count-3];
                alert("city name is: " + city);
            }
            else  {
                alert("address not found");
            }
    }
     else {
        alert("Geocoder failed due to: " + status);
    }
}

);

Git adding files to repo

After adding files to the stage, you need to commit them with git commit -m "comment" after git add .. Finally, to push them to a remote repository, you need to git push <remote_repo> <local_branch>.

MySQL ORDER BY multiple column ASC and DESC

Ok, I THINK I understand what you want now, and let me clarify to confirm before the query. You want 1 record for each user. For each user, you want their BEST POINTS score record. Of the best points per user, you want the one with the best average time. Once you have all users "best" values, you want the final results sorted with best points first... Almost like ranking of a competition.

So now the query. If the above statement is accurate, you need to start with getting the best point/average time per person and assigning a "Rank" to that entry. This is easily done using MySQL @ variables. Then, just include a HAVING clause to only keep those records ranked 1 for each person. Finally apply the order by of best points and shortest average time.

select
      U.UserName,
      PreSortedPerUser.Point,
      PreSortedPerUser.Avg_Time,
      @UserRank := if( @lastUserID = PreSortedPerUser.User_ID, @UserRank +1, 1 ) FinalRank,
      @lastUserID := PreSortedPerUser.User_ID
   from
      ( select
              S.user_id,
              S.point,
              S.avg_time
           from
              Scores S
           order by
              S.user_id,
              S.point DESC,
              S.Avg_Time ) PreSortedPerUser
         JOIN Users U
            on PreSortedPerUser.user_ID = U.ID,
      ( select @lastUserID := 0,
               @UserRank := 0 ) sqlvars 
   having
      FinalRank = 1
   order by
      Point Desc,
      Avg_Time

Results as handled by SQLFiddle

Note, due to the inline @variables needed to get the answer, there are the two extra columns at the end of each row. These are just "left-over" and can be ignored in any actual output presentation you are trying to do... OR, you can wrap the entire thing above one more level to just get the few columns you want like

select 
      PQ.UserName,
      PQ.Point,
      PQ.Avg_Time
   from
      ( entire query above pasted here ) as PQ

Java8: sum values from specific field of the objects in a list

You can also collect with an appropriate summing collector like Collectors#summingInt(ToIntFunction)

Returns a Collector that produces the sum of a integer-valued function applied to the input elements. If no elements are present, the result is 0.

For example

Stream<Obj> filtered = list.stream().filter(o -> o.field > 10);
int sum = filtered.collect(Collectors.summingInt(o -> o.field));

How to remove a directory from git repository?

I already had committed the folder before and want to remove the directory in the history as well.

I did the following:

Add folder to .gitignore:

echo Folder_Name/ >> .gitignore

Remove from all commits:

git filter-branch --index-filter 'git rm -rf --cached --ignore-unmatch Folder_Name/' --prune-empty --tag-name-filter cat -- --all

remove the refs from the old commits:

git for-each-ref --format="%(refname)" refs/original/ | xargs -n 1 git update-ref -d

Ensure all old refs are fully removed

rm -Rf .git/logs .git/refs/original

Perform a garbage collection

git gc --prune=all --aggressive

push you changes to the online repository:

git push

You are done here.

But you can to the following to push all the changes to all branches with: But be careful with this command!

git push origin --all --force
git push origin --tags --force

After that the folder was removed from git, but was not deleted from local disk.

JavaScript: How to find out if the user browser is Chrome?

_x000D_
_x000D_
console.log(JSON.stringify({_x000D_
  isAndroid: /Android/.test(navigator.userAgent),_x000D_
  isCordova: !!window.cordova,_x000D_
  isEdge: /Edge/.test(navigator.userAgent),_x000D_
  isFirefox: /Firefox/.test(navigator.userAgent),_x000D_
  isChrome: /Google Inc/.test(navigator.vendor),_x000D_
  isChromeIOS: /CriOS/.test(navigator.userAgent),_x000D_
  isChromiumBased: !!window.chrome && !/Edge/.test(navigator.userAgent),_x000D_
  isIE: /Trident/.test(navigator.userAgent),_x000D_
  isIOS: /(iPhone|iPad|iPod)/.test(navigator.platform),_x000D_
  isOpera: /OPR/.test(navigator.userAgent),_x000D_
  isSafari: /Safari/.test(navigator.userAgent) && !/Chrome/.test(navigator.userAgent),_x000D_
  isTouchScreen: ('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch,_x000D_
  isWebComponentsSupported: 'registerElement' in document && 'import' in document.createElement('link') && 'content' in document.createElement('template')_x000D_
}, null, '  '));
_x000D_
_x000D_
_x000D_

load jquery after the page is fully loaded

If you're trying to avoid loading jquery until your content has been loaded, the best way is to simply put the reference to it in the bottom of your page, like many other answers have said.

General tips on Jquery usage:

  1. Use a CDN. This way, your site can use the cached version a user likely has on their computer. The // at the beginning allows it to be called (and use the same resource) whether it's http or https. Example:

    <script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

Using a CDN has a couple of big benefits: it makes it more likely that users have it cached from another site, so there will be no download (and no render-blocking). Further, CDNs use the closest, fastest connection available, meaning that if they do need to load it, it will probably be faster than connecting to your server. More info from Google.

  1. Put scripts at the bottom. Move as much of your js to the bottom of the page as possible. I use php to include a file with all my JS resources below the footer.

  2. If you're using a template system, you may need to have javascript spread throughout the html output. If you're using jquery in scripts that get called as the page renders, this will cause errors. To have your scripts wait until jquery is loaded, put them into

    window.onload() = function () { //... your js that isn't called by user interaction ... }

This will prevent errors but still run before user interaction and without timers.

Of course, if jquery is cached, it won't matter too much where you put it, except to page speed tools that will tell you you're blocking rendering.

How to display .svg image using swift

To render SVG file you can use Macaw. Also Macaw supports transformations, user events, animation and various effects.

You can render SVG file with zero lines of code. For more info please check this article: Render SVG file with Macaw.

DISCLAIMER: I am affiliated with this project.

python NameError: name 'file' is not defined

It seems that your project is written in Python < 3. This is because the file() builtin function is removed in Python 3. Try using Python 2to3 tool or edit the erroneous file yourself.

EDIT: BTW, the project page clearly mentions that

Gunicorn requires Python 2.x >= 2.5. Python 3.x support is planned.

Maven Install on Mac OS X

You can install maven using homebrew. The command is $ brew install maven

MongoDB query with an 'or' condition

In case anyone finds it useful, www.querymongo.com does translation between SQL and MongoDB, including OR clauses. It can be really helpful for figuring out syntax when you know the SQL equivalent.

In the case of OR statements, it looks like this

SQL:

SELECT * FROM collection WHERE columnA = 3 OR columnB = 'string';

MongoDB:

db.collection.find({
    "$or": [{
        "columnA": 3
    }, {
        "columnB": "string"
    }]
});

How to make HTTP Post request with JSON body in Swift

    var request = URLRequest(url: URL(string:  "your URL")!)
    request.httpMethod = "POST"


    let postString =  String(format: "email=%@&lang=%@", arguments: [txt_emailVirify.text!, language!])
    print(postString)

    emailString = txt_emailVirify.text!

    request.httpBody = postString.data(using: .utf8)
    request.addValue("delta141forceSEAL8PARA9MARCOSBRAHMOS", forHTTPHeaderField: "Authorization")
    request.addValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
    request.addValue("application/json", forHTTPHeaderField: "Accept")


    let task = URLSession.shared.dataTask(with: request) { data, response, error in
        guard let data = data, error == nil
            else
        {
            print("error=\(String(describing: error))")
            return
        }

        do
        {

            let dictionary = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! NSDictionary
            print(dictionary)

            let status = dictionary.value(forKey: "status") as! String
            let sts = Int(status)
            DispatchQueue.main.async()
                {
                    if sts == 200
                    {
                        print(dictionary)


                    }
                    else
                    {
                       self.alertMessageOk(title: self.Alert!, message: dictionary.value(forKey: "message") as! String)


                    }
            }
        }
        catch
        {
            print(error)
        }

    }
    task.resume()

JavaScript calculate the day of the year (1 - 366)

It always get's me worried when mixing maths with date functions (it's so easy to miss some leap year other detail). Say you have:

var d = new Date();

I would suggest using the following, days will be saved in day:

for(var day = d.getDate(); d.getMonth(); day += d.getDate())
    d.setDate(0);

Can't see any reason why this wouldn't work just fine (and I wouldn't be so worried about the few iterations since this will not be used so intensively).

error: command 'gcc' failed with exit status 1 on CentOS

Is gcc installed?

sudo yum install gcc

When do you use Git rebase instead of Git merge?

  • Generally use merge
  • If you are only one developer you can use rebase to have a clear history.
  • In shared projects don't use rebase because cache sums are changed

enter image description here

javac: file not found: first.java Usage: javac <options> <source files>

Here is the way I executed the program without environment variable configured.

Java file execution procedure: After you saved a file MyFirstJavaProgram.java

Enter the whole Path of "Javac" followed by java file For executing output Path of followed by comment <-cp> followed by followed by

Given below is the example of execution

C:\Program Files\Java\jdk1.8.0_101\bin>javac C:\Sample\MyFirstJavaProgram2.java C:\Program Files\Java\jdk1.8.0_101\bin>java -cp C:\Sample MyFirstJavaProgram2 Hello World

How to undo a SQL Server UPDATE query?

If you already have a full backup from your database, fortunately, you have an option in SQL Management Studio. In this case, you can use the following steps:

  1. Right click on database -> Tasks -> Restore -> Database.

  2. In General tab, click on Timeline -> select Specific date and time option.

  3. Move the timeline slider to before update command time -> click OK.

  4. In the destination database name, type a new name.

  5. In the Files tab, check in Reallocate all files to folder and then select a new path to save your recovered database.

  6. In the options tab, check in Overwrite ... and remove Take tail-log... check option.

  7. Finally, click on OK and wait until the recovery process is over.

I have used this method myself in an operational database and it was very useful.

How to create named and latest tag in Docker?

Here is my bash script

docker build -t ${IMAGE}:${VERSION} .
docker tag ${IMAGE}:${VERSION} ${IMAGE}:latest

You can then remove untagged images if you rebuilt the same version with

docker rmi $(docker images | grep "^<none>" | awk "{print $3}")

link

or

docker rmi $(docker images | grep "^<none>" | tr -s " " | cut -d' ' -f3 | tr '\n' ' ')

or

Clean up commands:

Docker 1.13 introduces clean-up commands. To remove all unused containers, images, networks and volumes:

docker system prune

or individually:

docker container prune
docker image prune
docker network prune
docker volume prune

How do I download the Android SDK without downloading Android Studio?

Navigate to the "Get just the command line tools" section of the android downloads page, and download the tools for your system.

For Windows:

Extract the contents to C:\Android\android-sdk

Navigate to C:\Android\android-sdk\tools\bin and open a command line window
(shift + right click)

Run the following to download the latest android package:

sdkmanager "platforms;android-25" 

Update everything

sdkmanager --update

Other operation systems Do pretty much the same, but not using windows directories.

The sdkmanager page gives more info in to what commands to use to install your sdk.

Oracle JDBC ojdbc6 Jar as a Maven Dependency

Since Oracle is the licensed product, there are issue in adding maven dependency directly. To add any version of the ojdbc.jar, below 2 steps could do.

  1. Run the below command to install ojdbc.jar into local maven repository.
/opt/apache-maven/bin/mvn install:install-file
    -Dfile=<path-to-file>/ojdbc7.jar
    -DgroupId=com.oracle
    -DartifactId=ojdbc7
    -Dversion=12.1.0.1.0
    -Dpackaging=jar

This will add the dependency into local repository.

  1. Now, add the dependency in the pom file
<dependency>
    <groupId>com.oracle</groupId>
    <artifactId>ojdbc7</artifactId>
    <version>12.1.0.1.0</version>
</dependency>

Best way to copy a database (SQL Server 2008)

Its hard to detach your production dB or other running dB's and deal with that downtime, so I almost always use a Backup / restore method.

If you also want to make sure to keep your login's in sync check out the MS KB article on using the stored proc sp_help_revlogin to do this.

How to change the scrollbar color using css

Your css will only work in IE browser. And the css suggessted by hayk.mart will olny work in webkit browsers. And by using different css hacks you can't style your browsers scroll bars with a same result.

So, it is better to use a jQuery/Javascript plugin to achieve a cross browser solution with a same result.

Solution:

By Using jScrollPane a jQuery plugin, you can achieve a cross browser solution

See This Demo

Replace only some groups with Regex

If you don't want to change your pattern you can use the Group Index and Length properties of a matched group.

var text = "example-123-example";
var pattern = @"-(\d+)-";
var regex = new RegEx(pattern);
var match = regex.Match(text);

var firstPart = text.Substring(0,match.Groups[1].Index);    
var secondPart = text.Substring(match.Groups[1].Index + match.Groups[1].Length);
var fullReplace = firstPart + "AA" + secondPart;

Possible to make labels appear when hovering over a point in matplotlib?

The other answers did not address my need for properly showing tooltips in a recent version of Jupyter inline matplotlib figure. This one works though:

import matplotlib.pyplot as plt
import numpy as np
import mplcursors
np.random.seed(42)

fig, ax = plt.subplots()
ax.scatter(*np.random.random((2, 26)))
ax.set_title("Mouse over a point")
crs = mplcursors.cursor(ax,hover=True)

crs.connect("add", lambda sel: sel.annotation.set_text(
    'Point {},{}'.format(sel.target[0], sel.target[1])))
plt.show()

Leading to something like the following picture when going over a point with mouse: enter image description here

Server unable to read htaccess file, denying access to be safe

I had this problem too. My advice is look in your server error log file. For me, it was that the top directory for the project was not readable. The error log clearly stated this. A simple

sudo chmod 755 <site_top_folder>

fixed it for me.

Pandas: rolling mean by time interval

To keep it basic, I used a loop and something like this to get you started (my index are datetimes):

import pandas as pd
import datetime as dt

#populate your dataframe: "df"
#...

df[df.index<(df.index[0]+dt.timedelta(hours=1))] #gives you a slice. you can then take .sum() .mean(), whatever

and then you can run functions on that slice. You can see how adding an iterator to make the start of the window something other than the first value in your dataframes index would then roll the window (you could use a > rule for the start as well for example).

Note, this may be less efficient for SUPER large data or very small increments as your slicing may become more strenuous (works for me well enough for hundreds of thousands of rows of data and several columns though for hourly windows across a few weeks)

How to drop column with constraint?

Find the default constraint with this query here:

SELECT
    df.name 'Constraint Name' ,
    t.name 'Table Name',
    c.NAME 'Column Name'
FROM sys.default_constraints df
INNER JOIN sys.tables t ON df.parent_object_id = t.object_id
INNER JOIN sys.columns c ON df.parent_object_id = c.object_id AND df.parent_column_id = c.column_id

This gives you the name of the default constraint, as well as the table and column name.

When you have that information you need to first drop the default constraint:

ALTER TABLE dbo.YourTable
DROP CONSTRAINT name-of-the-default-constraint-here

and then you can drop the column

ALTER TABLE dbo.YourTable DROP COLUMN YourColumn

How to add a reference programmatically

There are two ways to add references using VBA. .AddFromGuid(Guid, Major, Minor) and .AddFromFile(Filename). Which one is best depends on what you are trying to add a reference to. I almost always use .AddFromFile because the things I am referencing are other Excel VBA Projects and they aren't in the Windows Registry.

The example code you are showing will add a reference to the workbook the code is in. I generally don't see any point in doing that because 90% of the time, before you can add the reference, the code has already failed to compile because the reference is missing. (And if it didn't fail-to-compile, you are probably using late binding and you don't need to add a reference.)

If you are having problems getting the code to run, there are two possible issues.

  1. In order to easily use the VBE's object model, you need to add a reference to Microsoft Visual Basic for Application Extensibility. (VBIDE)
  2. In order to run Excel VBA code that changes anything in a VBProject, you need to Trust access to the VBA Project Object Model. (In Excel 2010, it is located in the Trust Center - Macro Settings.)

Aside from that, if you can be a little more clear on what your question is or what you are trying to do that isn't working, I could give a more specific answer.

How to add a button programmatically in VBA next to some sheet cell data?

I think this is enough to get you on a nice path:

Sub a()
  Dim btn As Button
  Application.ScreenUpdating = False
  ActiveSheet.Buttons.Delete
  Dim t As Range
  For i = 2 To 6 Step 2
    Set t = ActiveSheet.Range(Cells(i, 3), Cells(i, 3))
    Set btn = ActiveSheet.Buttons.Add(t.Left, t.Top, t.Width, t.Height)
    With btn
      .OnAction = "btnS"
      .Caption = "Btn " & i
      .Name = "Btn" & i
    End With
  Next i
  Application.ScreenUpdating = True
End Sub

Sub btnS()
 MsgBox Application.Caller
End Sub

It creates the buttons and binds them to butnS(). In the btnS() sub, you should show your dialog, etc.

Mathematica graphics

Using python map and other functional tools

Here's an overview of the parameters to the map(function, *sequences) function:

  • function is the name of your function.
  • sequences is any number of sequences, which are usually lists or tuples. map will iterate over them simultaneously and give the current values to function. That's why the number of sequences should equal the number of parameters to your function.

It sounds like you're trying to iterate for some of function's parameters but keep others constant, and unfortunately map doesn't support that. I found an old proposal to add such a feature to Python, but the map construct is so clean and well-established that I doubt something like that will ever be implemented.

Use a workaround like global variables or list comprehensions, as others have suggested.

:before and background-image... should it work?

The problem with other answers here is that they use position: absolute;

This makes it difficult to layout the element itself in relation to the ::before pseudo-element. For example, if you wish to show an image before a link like this: enter image description here

Here's how I was able to achieve the layout in the picture:

_x000D_
_x000D_
a::before {_x000D_
  content: "";_x000D_
  float: left;_x000D_
  width: 16px;_x000D_
  height: 16px;_x000D_
  margin-right: 5px;_x000D_
  background: url(../../lhsMenu/images/internal_link.png) no-repeat 0 0;_x000D_
  background-size: 80%;_x000D_
}
_x000D_
_x000D_
_x000D_

Note that this method allows you to scale the background image, as well as keep the ability to use margins and padding for layout.

PreparedStatement setNull(..)

preparedStatement.setNull(index, java.sql.Types.NULL);

that should work for any type. Though in some cases failure happens on the server-side, like: for SQL:

COALESCE(?, CURRENT_TIMESTAMP)

Oracle 18XE fails with the wrong type: expected DATE, got STRING -- that is a perfectly valid failure;

Bottom line: it is good to know the type if you call .setNull()

TypeError: 'float' object is not callable

The problem is with -3.7(prof[x]), which looks like a function call (note the parens). Just use a * like this -3.7*prof[x].

Casting objects in Java

Sometimes you will like to receive as argument a Parent reference and inside you probably want to do something specific of a child.

abstract class Animal{
 public abstract void move();
}
class Shark extends Animal{
 public void move(){
  swim();
 }
 public void swim(){}
 public void bite(){}
}
class Dog extends Animal{
 public void move(){
  run();
 }
 public void run(){}
 public void bark(){}
}

...

void somethingSpecific(Animal animal){
 // Here you don't know and may don't care which animal enters
 animal.move(); // You can call parent methods but you can't call bark or bite.
 if(animal instanceof Shark){
  Shark shark = (Shark)animal;
  shark.bite(); // Now you can call bite!
 }
 //doSomethingSharky(animal); // You cannot call this method.
}

...

In above's method you can pass either Shark or Dog, but what if you have something like this:

void doSomethingSharky(Shark shark){
 //Here you cannot receive an Animal reference
}

That method can only be called by passing shark references So if you have an Animal (and it is deeply a Shark) you can call it like this:

Animal animal...
doSomethingSharky((Shark) animal)

Bottom line, you can use Parent references and it is usually better when you don't care about the implementation of the parent and use casting to use the Child as an specific object, it will be exactly the same object, but your reference know it, if you don't cast it, your reference will point to the same object but cannot be sure what kind of Animal would it be, therefore will only allow you to call known methods.

How to set the size of button in HTML

button { 
  width:1000px; 
} 

or even

 button { 
    width:1000px !important
 } 

If thats what you mean

How can I truncate a double to only two decimal places in Java?

Here is the method I use:

double a=3.545555555; // just assigning your decimal to a variable
a=a*100;              // this sets a to 354.555555
a=Math.floor(a);      // this sets a to 354
a=a/100;              // this sets a to 3.54 and thus removing all your 5's

This can also be done:

a=Math.floor(a*100) / 100;

Node.js: printing to console without a trailing newline?

In Windows console (Linux, too), you should replace '\r' with its equivalent code \033[0G:

process.stdout.write('ok\033[0G');

This uses a VT220 terminal escape sequence to send the cursor to the first column.

How to make Bitmap compress without change the bitmap size?

i think you use this method to compress the bitmap

BitmapFactory.Option imageOpts = new BitmapFactory.Options ();
imageOpts.inSampleSize = 2;   // for 1/2 the image to be loaded
Bitmap thumb = Bitmap.createScaledBitmap (BitmapFactory.decodeFile(photoPath, imageOpts), 96, 96, false);

Create <div> and append <div> dynamically

var arrayDiv = new Array();
    for(var i=0; i <= 1; i++){
        arrayDiv[i] = document.createElement('div');
        arrayDiv[i].id = 'block' + i;
        arrayDiv[i].className = 'block' + i;
    }
    document.body.appendChild(arrayDiv[0].appendChild(arrayDiv[1]));

Installing R with Homebrew

I used this tutorial to install R on my mac, and it had me install xquartz and a fortran complier (gfortran) as well.

My suggestion would be to brew untap homebrew/science and then brew tap homebrew/science and try again, also, make sure you don't have any errors when you run brew doctor

Hope this helps

ComboBox.SelectedText doesn't give me the SelectedText

I face this problem 5 minutes before.

I think that a solution (with visual studio 2005) is:

myString = comboBoxTest.GetItemText(comboBoxTest.SelectedItem);

Forgive me if I am wrong.

Understanding unique keys for array children in React.js

When you don’t have stable IDs for rendered items, you may use the item index as a key as a last resort:

const todoItems = todos.map((todo, index) =>
// Only do this if items have no stable IDs
   <li key={index}>
      {todo.text}
   </li>
);

Please refer to List and Keys - React

Batch File: ( was unexpected at this time

You are getting that error because when the param1 if statements are evaluated, param is always null due to being scoped variables without delayed expansion.

When parentheses are used, all the commands and variables within those parentheses are expanded. And at that time, param1 has no value making the if statements invalid. When using delayed expansion, the variables are only expanded when the command is actually called.

Also I recommend using if not defined command to determine if a variable is set.

@echo off
setlocal EnableExtensions EnableDelayedExpansion
cls
title ~USB Wizard~
echo What do you want to do?
echo 1.Enable/Disable USB Storage Devices.
echo 2.Enable/Disable Writing Data onto USB Storage.
echo 3.~Yet to come~.

set "a=%globalparam1%"
goto :aCheck
:aPrompt
set /p "a=Enter Choice: "
:aCheck
if not defined a goto :aPrompt
echo %a%

IF "%a%"=="2" (
    title USB WRITE LOCK
    echo What do you want to do?
    echo 1.Apply USB Write Protection
    echo 2.Remove USB Write Protection

    ::param1
    set "param1=%globalparam2%"
    goto :param1Check
    :param1Prompt
    set /p "param1=Enter Choice: "
    :param1Check
    if not defined param1 goto :param1Prompt
    echo !param1!

    if "!param1!"=="1" (
        REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies\ /v WriteProtect /t REG_DWORD /d 00000001 
        echo USB Write is Locked!
    )
    if "!param1!"=="2" (
        REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies\ /v WriteProtect /t REG_DWORD /d 00000000
        echo USB Write is Unlocked! 
    )
)
pause
endlocal

Declare a Range relative to the Active Cell with VBA

There is an .Offset property on a Range class which allows you to do just what you need

ActiveCell.Offset(numRows, numCols)

follow up on a comment:

Dim newRange as Range
Set newRange = Range(ActiveCell, ActiveCell.Offset(numRows, numCols))

and you can verify by MsgBox newRange.Address

and here's how to assign this range to an array

Factorial using Recursion in Java

The key point that you missing here is that the variable "result" is a stack variable, and as such it does not get "replaced". To elaborate, every time fact is called, a NEW variable called "result" is created internally in the interpreter and linked to that invocation of the methods. This is in contrast of object fields which linked to the instance of the object and not a specific method call

SQL Query - Change date format in query to DD/MM/YYYY

If DB is SQL Server then

select Convert(varchar(10),CONVERT(date,YourDateColumn,106),103)

Most efficient way to concatenate strings in JavaScript?

You can also do string concat with template literals. I updated the other posters' JSPerf tests to include it.

for (var res = '', i = 0; i < data.length; i++) {
  res = `${res}${data[i]}`;
}

How to change font size in a textbox in html

For a <input type='text'> element:

input { font-size: 18px; }

or for a <textarea>:

textarea { font-size: 18px; }

or for a <select>:

select { font-size: 18px; }

you get the drift.

How to clear the logs properly for a Docker container?

On my Ubuntu servers even as sudo I would get Cannot open ‘/var/lib/docker/containers/*/*-json.log’ for writing: No such file or directory

But combing the docker inspect and truncate answers worked :

sudo truncate -s 0 `docker inspect --format='{{.LogPath}}' <container>`

#pragma mark in Swift?

Try this:

// MARK: Reload TableView

func reloadTableView(){

    tableView.reload()
}

How to get UTC timestamp in Ruby?

Usually timestamp has no timezone.

% irb
> Time.now.to_i == Time.now.getutc.to_i
=> true

How to list only files and not directories of a directory Bash?

find files: ls -l /home | grep "^-" | tr -s ' ' | cut -d ' ' -f 9

find directories: ls -l /home | grep "^d" | tr -s ' ' | cut -d ' ' -f 9

find links: ls -l /home | grep "^l" | tr -s ' ' | cut -d ' ' -f 9

tr -s ' ' turns the output into a space-delimited file the cut command says the delimiter is a space, and return the 9th field (always the filename/directory name/linkname).

I use this all the time!

How can I make a checkbox readonly? not disabled?

I use JQuery so I can use the readonly attribute on checkboxes.

//This will make all read-only check boxes truly read-only
$('input[type="checkbox"][readonly]').on("click.readonly", function(event){event.preventDefault();}).css("opacity", "0.5");

If you want the checkbox to be editable again then you need to do the following for the specific checkbox.

$('specific checkbox').off('.readonly').removeAttr("readonly").css("opacity", "1")

Regular expression to match standard 10 digit phone number

^(\+1)?\s?(\([1-9]\d{2}\)|[1-9]\d{2})(-|\s|.)\d{3}(-|\s|.)\d{4}

Fragments within Fragments

Nested fragments are supported in android 4.2 and later

The Android Support Library also now supports nested fragments, so you can implement nested fragment designs on Android 1.6 and higher.

To nest a fragment, simply call getChildFragmentManager() on the Fragment in which you want to add a fragment. This returns a FragmentManager that you can use like you normally do from the top-level activity to create fragment transactions. For example, here’s some code that adds a fragment from within an existing Fragment class:

Fragment videoFragment = new VideoPlayerFragment();
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
transaction.add(R.id.video_fragment, videoFragment).commit();

To get more idea about nested fragments, please go through these tutorials
Part 1
Part 2
Part 3

and here is a SO post which discuss about best practices for nested fragments.

How to get thread id from a thread pool?

If you are using logging then thread names will be helpful. A thread factory helps with this:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

public class Main {

    static Logger LOG = LoggerFactory.getLogger(Main.class);

    static class MyTask implements Runnable {
        public void run() {
            LOG.info("A pool thread is doing this task");
        }
    }

    public static void main(String[] args) {
        ExecutorService taskExecutor = Executors.newFixedThreadPool(5, new MyThreadFactory());
        taskExecutor.execute(new MyTask());
        taskExecutor.shutdown();
    }
}

class MyThreadFactory implements ThreadFactory {
    private int counter;
    public Thread newThread(Runnable r) {
        return new Thread(r, "My thread # " + counter++);
    }
}

Output:

[   My thread # 0] Main         INFO  A pool thread is doing this task

Can I extend a class using more than 1 class in PHP?

One of the problems of PHP as a programming language is the fact that you can only have single inheritance. This means a class can only inherit from one other class.

However, a lot of the time it would be beneficial to inherit from multiple classes. For example, it might be desirable to inherit methods from a couple of different classes in order to prevent code duplication.

This problem can lead to class that has a long family history of inheritance which often does not make sense.

In PHP 5.4 a new feature of the language was added known as Traits. A Trait is kind of like a Mixin in that it allows you to mix Trait classes into an existing class. This means you can reduce code duplication and get the benefits whilst avoiding the problems of multiple inheritance.

Traits

How to insert new cell into UITableView in Swift

Use beginUpdates and endUpdates to insert a new cell when the button clicked.

As @vadian said in comment, begin/endUpdates has no effect for a single insert/delete/move operation

First of all, append data in your tableview array

Yourarray.append([labeltext])  

Then update your table and insert a new row

// Update Table Data
tblname.beginUpdates()
tblname.insertRowsAtIndexPaths([
NSIndexPath(forRow: Yourarray.count-1, inSection: 0)], withRowAnimation: .Automatic)
tblname.endUpdates()

This inserts cell and doesn't need to reload the whole table but if you get any problem with this, you can also use tableview.reloadData()


Swift 3.0

tableView.beginUpdates()
tableView.insertRows(at: [IndexPath(row: yourArray.count-1, section: 0)], with: .automatic)
tableView.endUpdates()

Objective-C

[self.tblname beginUpdates];
NSArray *arr = [NSArray arrayWithObject:[NSIndexPath indexPathForRow:Yourarray.count-1 inSection:0]];
[self.tblname insertRowsAtIndexPaths:arr withRowAnimation:UITableViewRowAnimationAutomatic];
[self.tblname endUpdates];

Laravel 5: Retrieve JSON array from $request

You can use getContent() method on Request object.

$request->getContent() //json as a string.

Print empty line?

This is are other ways of printing empty lines in python

# using \n after the string creates an empty line after this string is passed to the the terminal.
print("We need to put about", average_passengers_per_car, "in each car. \n") 
print("\n") #prints 2 empty lines 
print() #prints 1 empty line 

Redirect Windows cmd stdout and stderr to a single file

Background info from MSKB

While the accepted answer to this question is correct, it really doesn't do much to explain why it works, and since the syntax is not immediately clear I did a quick google to find out what was actually going on. In the hopes that this information is helpful to others, I'm posting it here.

Taken from MS Support KB 110930.


From MSKB110930

Redirecting Error Messages from Command Prompt: STDERR/STDOUT

Summary

When redirecting output from an application using the '>' symbol, error messages still print to the screen. This is because error messages are often sent to the Standard Error stream instead of the Standard Out stream.

Output from a console (Command Prompt) application or command is often sent to two separate streams. The regular output is sent to Standard Out (STDOUT) and the error messages are sent to Standard Error (STDERR). When you redirect console output using the ">" symbol, you are only redirecting STDOUT. In order to redirect STDERR you have to specify '2>' for the redirection symbol. This selects the second output stream which is STDERR.

Example

The command dir file.xxx (where file.xxx does not exist) will display the following output:

Volume in drive F is Candy Cane Volume Serial Number is 34EC-0876

File Not Found

If you redirect the output to the NUL device using dir file.xxx > nul, you will still see the error message part of the output, like this:

File Not Found

To redirect (only) the error message to NUL, use the following command:

dir file.xxx 2> nul

Or, you can redirect the output to one place, and the errors to another.

dir file.xxx > output.msg 2> output.err

You can print the errors and standard output to a single file by using the "&1" command to redirect the output for STDERR to STDOUT and then sending the output from STDOUT to a file:

dir file.xxx 1> output.msg 2>&1

What would be the best method to code heading/title for <ul> or <ol>, Like we have <caption> in <table>?

Though this is old, I'm updating it for others who might find this question when searching later.

@Matt Kelliher:

Using the css :before and a data-* attribute for the list is a great idea, but can be modified slightly to be more handicap accessible as well:

HTML:

<ul aria-label="Vehicle Models Available:"> 
    <li>Dodge Shadow</li>
    <li>Ford Focus</li>
    <li>Chevy Lumina</li>
</ul>

CSS:

ul:before{
    content:attr(aria-label);
    font-size:120%;
    font-weight:bold;
    margin-left:-15px;
}

This will make a list with the "header" pseudo element above it with text set to the value in the aria-label attribute. You can then easily style it to your needs.

The benefit of this over using a data-* attribute is that aria-label will be read off by screen readers as a "label" for the list, which is semantically correct for your intended use of this data.

Note: IE8 supports :before attributes, but must use the single colon version (and must have a valid doctype defined). IE7 does not support :before, but Modernizer or Selectivizr should fix that issue for you. All modern browsers support the older :before syntax, but prefer that the ::before syntax be used. Generally the best way to handle this is to have an external stylesheet for IE7/8 that uses the old format and a general stylesheet using the new format, but in practice, most just use the old single colon format since it is still 100% cross browser, even if not technically valid for CSS3.

How to get the first and last date of the current year?

print Cast('1/1/' + cast(datepart(yyyy, getdate()) as nvarchar(4)) as date)

.htaccess File Options -Indexes on Subdirectories

htaccess files affect the directory they are placed in and all sub-directories, that is an htaccess file located in your root directory (yoursite.com) would affect yoursite.com/content, yoursite.com/content/contents, etc.

http://www.javascriptkit.com/howto/htaccess.shtml

Location of my.cnf file on macOS

For Mac , what worked for me is creating a .my.cnf file in my ~ path. Hope this helps.

How to get error message when ifstream open fails

The std::system_error example above is slightly incorrect. std::system_category() will map the error codes from system's native error code facility. For *nix, this is errno. For Win32, it is GetLastError(). ie, on Windows, the above example will print

failed to open C:\path\to\forbidden: The data is invalid

because EACCES is 13 which is the Win32 error code ERROR_INVALID_DATA

To fix it, either use the system's native error code facility, eg on Win32

throw new std::system_error(GetLastError(), std::system_category(), "failed to open"+ filename);

Or use errno and std::generic_category(), eg

throw new std::system_error(errno, std::generic_category(), "failed to open"+ filename);

What does the "yield" keyword do?

Think of it this way:

An iterator is just a fancy sounding term for an object that has a next() method. So a yield-ed function ends up being something like this:

Original version:

def some_function():
    for i in xrange(4):
        yield i

for i in some_function():
    print i

This is basically what the Python interpreter does with the above code:

class it:
    def __init__(self):
        # Start at -1 so that we get 0 when we add 1 below.
        self.count = -1

    # The __iter__ method will be called once by the 'for' loop.
    # The rest of the magic happens on the object returned by this method.
    # In this case it is the object itself.
    def __iter__(self):
        return self

    # The next method will be called repeatedly by the 'for' loop
    # until it raises StopIteration.
    def next(self):
        self.count += 1
        if self.count < 4:
            return self.count
        else:
            # A StopIteration exception is raised
            # to signal that the iterator is done.
            # This is caught implicitly by the 'for' loop.
            raise StopIteration

def some_func():
    return it()

for i in some_func():
    print i

For more insight as to what's happening behind the scenes, the for loop can be rewritten to this:

iterator = some_func()
try:
    while 1:
        print iterator.next()
except StopIteration:
    pass

Does that make more sense or just confuse you more? :)

I should note that this is an oversimplification for illustrative purposes. :)

getElementsByClassName not working

There are several issues:

  1. Class names (and IDs) are not allowed to start with a digit.
  2. You have to pass a class to getElementsByClassName().
  3. You have to iterate of the result set.

Example (untested):

<script type="text/javascript">
function hideTd(className){
    var elements = document.getElementsByClassName(className);
    for(var i = 0, length = elements.length; i < length; i++) {
       if( elements[i].textContent == ''){
          elements[i].style.display = 'none';
       } 
    }

  }
</script>
</head>
<body onload="hideTd('td');">
<table border="1">
  <tr>
    <td class="td">not empty</td>
  </tr>
  <tr>
    <td class="td"></td>
  </tr>
  <tr>
    <td class="td"></td>
  </tr>
</table>
</body>

Note that getElementsByClassName() is not available up to and including IE8.

Update:

Alternatively you can give the table an ID and use:

var elements = document.getElementById('tableID').getElementsByTagName('td');

to get all td elements.

To hide the parent row, use the parentNode property of the element:

elements[i].parentNode.style.display = "none";

Difference between partition key, composite key and clustering key in Cassandra?

In database design, a compound key is a set of superkeys that is not minimal.

A composite key is a set that contains a compound key and at least one attribute that is not a superkey

Given table: EMPLOYEES {employee_id, firstname, surname}

Possible superkeys are:

{employee_id}
{employee_id, firstname}
{employee_id, firstname, surname}

{employee_id} is the only minimal superkey, which also makes it the only candidate key--given that {firstname} and {surname} do not guarantee uniqueness. Since a primary key is defined as a chosen candidate key, and only one candidate key exists in this example, {employee_id} is the minimal superkey, the only candidate key, and the only possible primary key.

The exhaustive list of compound keys is:

{employee_id, firstname}
{employee_id, surname}
{employee_id, firstname, surname}

The only composite key is {employee_id, firstname, surname} since that key contains a compound key ({employee_id,firstname}) and an attribute that is not a superkey ({surname}).

Getting the name of the currently executing method

Most answers here seems wrong.

    public static String getCurrentMethod() {
            return getCurrentMethod(1);
    }
    public static String getCurrentMethod(int skip) {
            return Thread.currentThread().getStackTrace()[1 + 1 + skip].getMethodName();
    }

Example:

    public static void main(String[] args) {
            aaa();
    }

    public static void aaa() {
            System.out.println("aaa  -> "  + getCurrentMethod( ) );
            System.out.println("aaa  -> "  + getCurrentMethod(0) );
            System.out.println("main -> "  + getCurrentMethod(1) );
    }

Outputs:

aaa  -> aaa
aaa  -> aaa
main -> main

Round double in two decimal places in C#?

Math.Round(inputValue, 2, MidpointRounding.AwayFromZero)

ValueError: not enough values to unpack (expected 11, got 1)

The error message is fairly self-explanatory

(a,b,c,d,e) = line.split()

expects line.split() to yield 5 elements, but in your case, it is only yielding 1 element. This could be because the data is not in the format you expect, a rogue malformed line, or maybe an empty line - there's no way to know.

To see what line is causing the issue, you could add some debug statements like this:

if len(line.split()) != 11:
    print line

As Martin suggests, you might also be splitting on the wrong delimiter.

Error 'LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt' after installing Visual Studio 2012 Release Preview

According to this thread in MSDN forums: VS2012 RC installation breaks VS2010 C++ projects, simply, take cvtres.exe from VS2010 SP1

C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\cvtres.exe

or from VS2012

C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\cvtres.exe

and copy it over the cvtres.exe in VS2010 RTM installation (the one without SP1)

C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\cvtres.exe

This way, you will effectively use the corrected version of cvtres.exe which is 11.0.51106.1.

Repeat the same steps for 64-bit version of the tool in C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\amd64\cvtres.exe.

This solution is an alternative to installation of SP1 for VS2010 - in some cases you simply can't install SP1 (i.e. if you need to support pre-SP1 builds).

Arithmetic overflow error converting numeric to data type numeric

Use TRY_CAST function in exact same way of CAST function. TRY_CAST takes a string and tries to cast it to a data type specified after the AS keyword. If the conversion fails, TRY_CAST returns a NULL instead of failing.

What is the reason and how to avoid the [FIN, ACK] , [RST] and [RST, ACK]

Here is a rough explanation of the concepts.

[ACK] is the acknowledgement that the previously sent data packet was received.

[FIN] is sent by a host when it wants to terminate the connection; the TCP protocol requires both endpoints to send the termination request (i.e. FIN).

So, suppose

  • host A sends a data packet to host B
  • and then host B wants to close the connection.
  • Host B (depending on timing) can respond with [FIN,ACK] indicating that it received the sent packet and wants to close the session.
  • Host A should then respond with a [FIN,ACK] indicating that it received the termination request (the ACK part) and that it too will close the connection (the FIN part).

However, if host A wants to close the session after sending the packet, it would only send a [FIN] packet (nothing to acknowledge) but host B would respond with [FIN,ACK] (acknowledges the request and responds with FIN).

Finally, some TCP stacks perform half-duplex termination, meaning that they can send [RST] instead of the usual [FIN,ACK]. This happens when the host actively closes the session without processing all the data that was sent to it. Linux is one operating system which does just this.

You can find a more detailed and comprehensive explanation here.

Angular JS update input field after change

You just need to correct the format of your html

<form>
    <li>Number 1: <input type="text" ng-model="one"/> </li>
    <li>Number 2: <input type="text" ng-model="two"/> </li>
        <li>Total <input type="text" value="{{total()}}"/>  </li>      
    {{total()}}

</form>

http://jsfiddle.net/YUza7/105/

HTML Upload MAX_FILE_SIZE does not appear to work

MAX_FILE_SIZE is in KB not bytes. You were right, it is in bytes. So, for a limit of 4MB convert 4MB in bytes {1024 * (1024 * 4)} try:

<input type="hidden" name="MAX_FILE_SIZE" value="4194304" /> 

enter image description here

Update 1

As explained by others, you will never get a warning for this. It's there just to impose a soft limit on server side.

Update 2

To answer your sub-question. Yes, there is a difference, you NEVER trust the user input. If you want to always impose a limit, you always must check its size. Don't trust what MAX_FILE_SIZE does, because it can be changed by a user. So, yes, you should check to make sure it's always up to or above the size you want it to be.

The difference is that if you have imposed a MAX_FILE_SIZE of 2MB and the user tries to upload a 4MB file, once they reach roughly the first 2MB of upload, the transfer will terminate and the PHP will stop accepting more data for that file. It will report the error on the files array.

Does Index of Array Exist

You can check the length of the array to see if item 25 is valid in the sense of being in the array, then you could use

if (array.Length > 25)
{ 
   if (array[25] != null)
   {
       //good
   }
}

to see if the array item itself has been set.

How to hide .php extension in .htaccess

The other option for using PHP scripts sans extension is

Options +MultiViews

Or even just following in the directories .htaccess:

DefaultType application/x-httpd-php

The latter allows having all filenames without extension script being treated as PHP scripts. While MultiViews makes the webserver look for alternatives, when just the basename is provided (there's a performance hit with that however).

Should image size be defined in the img tag height/width attributes or in CSS?

Option a. Simple straight fwd. What you see is what you get easy to make calculations.

Option b. Too messy to do this inline unless you want to have a site that can stretch. IE if you used the with:86em however modern browsers seem to handle this functionally adequately for my purposes.. . Personally the only time that i would use something like this is if i were to create a thumbnails catalogue.

/*css*/
ul.myThumbs{}
ul.myThumbs li {float:left; width:50px;}
ul.myThumbs li img{width:50px; height:50px;border:0;}

<!--html-->
<ul><li>
<img src="~/img/products/thumbs/productid.jpg" alt="" />
</li></ul>

Option c. Too messy to maintain.

How to display multiple notifications in android

Use the following method in your code.

Method call :-

notificationManager.notify(getCurrentNotificationId(getApplicationContext()), notification);

Method:-

  *Returns a unique notification id.
         */

        public static int getCurrentNotificationId(Context iContext){

            NOTIFICATION_ID_UPPER_LIMIT = 30000; // Arbitrary number.

            NOTIFICATION_ID_LOWER_LIMIT = 0;
            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(iContext);
        int previousTokenId= sharedPreferences.getInt("currentNotificationTokenId", 0);

        int currentTokenId= previousTokenId+1;

        SharedPreferences.Editor editor= sharedPreferences.edit();

        if(currentTokenId<NOTIFICATION_ID_UPPER_LIMIT) {

            editor.putInt("currentNotificationTokenId", currentTokenId); // }
        }else{
            //If reaches the limit reset to lower limit..
            editor.putInt("currentNotificationTokenId", NOTIFICATION_ID_LOWER_LIMIT);
        }

        editor.commit();

        return currentTokenId;
    }

T-SQL: Using a CASE in an UPDATE statement to update certain columns depending on a condition

I know this is a very old question, but this worked for me:

UPDATE TABLE SET FIELD1 =
CASE 
WHEN FIELD1 = Condition1 THEN 'Result1'
WHEN FIELD1 = Condition2 THEN 'Result2'
WHEN FIELD1 = Condition3 THEN 'Result3'
END;

Regards

How to open a web page from my application?

Accepted answer no longer works on .NET Core 3. To make it work, use the following method:

var psi = new ProcessStartInfo
{
    FileName = url,
    UseShellExecute = true
};
Process.Start (psi);

Java and unlimited decimal places?

I believe that you are looking for the java.lang.BigDecimal class.

How to do exponential and logarithmic curve fitting in Python? I found only polynomial fitting

Here's a linearization option on simple data that uses tools from scikit learn.

Given

import numpy as np

import matplotlib.pyplot as plt

from sklearn.linear_model import LinearRegression
from sklearn.preprocessing import FunctionTransformer


np.random.seed(123)

# General Functions
def func_exp(x, a, b, c):
    """Return values from a general exponential function."""
    return a * np.exp(b * x) + c


def func_log(x, a, b, c):
    """Return values from a general log function."""
    return a * np.log(b * x) + c


# Helper
def generate_data(func, *args, jitter=0):
    """Return a tuple of arrays with random data along a general function."""
    xs = np.linspace(1, 5, 50)
    ys = func(xs, *args)
    noise = jitter * np.random.normal(size=len(xs)) + jitter
    xs = xs.reshape(-1, 1)                                  # xs[:, np.newaxis]
    ys = (ys + noise).reshape(-1, 1)
    return xs, ys
transformer = FunctionTransformer(np.log, validate=True)

Code

Fit exponential data

# Data
x_samp, y_samp = generate_data(func_exp, 2.5, 1.2, 0.7, jitter=3)
y_trans = transformer.fit_transform(y_samp)             # 1

# Regression
regressor = LinearRegression()
results = regressor.fit(x_samp, y_trans)                # 2
model = results.predict
y_fit = model(x_samp)

# Visualization
plt.scatter(x_samp, y_samp)
plt.plot(x_samp, np.exp(y_fit), "k--", label="Fit")     # 3
plt.title("Exponential Fit")

enter image description here

Fit log data

# Data
x_samp, y_samp = generate_data(func_log, 2.5, 1.2, 0.7, jitter=0.15)
x_trans = transformer.fit_transform(x_samp)             # 1

# Regression
regressor = LinearRegression()
results = regressor.fit(x_trans, y_samp)                # 2
model = results.predict
y_fit = model(x_trans)

# Visualization
plt.scatter(x_samp, y_samp)
plt.plot(x_samp, y_fit, "k--", label="Fit")             # 3
plt.title("Logarithmic Fit")

enter image description here


Details

General Steps

  1. Apply a log operation to data values (x, y or both)
  2. Regress the data to a linearized model
  3. Plot by "reversing" any log operations (with np.exp()) and fit to original data

Assuming our data follows an exponential trend, a general equation+ may be:

enter image description here

We can linearize the latter equation (e.g. y = intercept + slope * x) by taking the log:

enter image description here

Given a linearized equation++ and the regression parameters, we could calculate:

  • A via intercept (ln(A))
  • B via slope (B)

Summary of Linearization Techniques

Relationship |  Example   |     General Eqn.     |  Altered Var.  |        Linearized Eqn.  
-------------|------------|----------------------|----------------|------------------------------------------
Linear       | x          | y =     B * x    + C | -              |        y =   C    + B * x
Logarithmic  | log(x)     | y = A * log(B*x) + C | log(x)         |        y =   C    + A * (log(B) + log(x))
Exponential  | 2**x, e**x | y = A * exp(B*x) + C | log(y)         | log(y-C) = log(A) + B * x
Power        | x**2       | y =     B * x**N + C | log(x), log(y) | log(y-C) = log(B) + N * log(x)

+Note: linearizing exponential functions works best when the noise is small and C=0. Use with caution.

++Note: while altering x data helps linearize exponential data, altering y data helps linearize log data.

Mercurial: how to amend the last commit?

GUI equivalent for hg commit --amend:

This also works from TortoiseHG's GUI (I'm using v2.5):

Swich to the 'Commit' view or, in the workbench view, select the 'working directory' entry. The 'Commit' button has an option named 'Amend current revision' (click the button's drop-down arrow to find it).

enter image description here

          ||
          ||
          \/

enter image description here

Caveat emptor:

This extra option will only be enabled if the mercurial version is at least 2.2.0, and if the current revision is not public, is not a patch and has no children. [...]

Clicking the button will call 'commit --amend' to 'amend' the revision.

More info about this on the THG dev channel

Python: Removing spaces from list objects

String methods return the modified string.

k = [x.replace(' ', '') for x in hello]

C program to check little vs. big endian

This is big endian test from a configure script:

#include <inttypes.h>
int main(int argc, char ** argv){
    volatile uint32_t i=0x01234567;
    // return 0 for big endian, 1 for little endian.
    return (*((uint8_t*)(&i))) == 0x67;
}

Remove all items from a FormArray in Angular

Use FormArray.clear() to remove all the elements of an array in a FormArray

Blur or dim background when Android PopupWindow active

Since PopupWindow just adds a View to WindowManager you can use updateViewLayout (View view, ViewGroup.LayoutParams params) to update the LayoutParams of your PopupWindow's contentView after calling show..().

Setting the window flag FLAG_DIM_BEHIND will dimm everything behind the window. Use dimAmount to control the amount of dim (1.0 for completely opaque to 0.0 for no dim).

Keep in mind that if you set a background to your PopupWindow it will put your contentView into a container, which means you need to update it's parent.

With background:

PopupWindow popup = new PopupWindow(contentView, width, height);
popup.setBackgroundDrawable(background);
popup.showAsDropDown(anchor);

View container = (View) popup.getContentView().getParent();
WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
WindowManager.LayoutParams p = (WindowManager.LayoutParams) container.getLayoutParams();
// add flag
p.flags |= WindowManager.LayoutParams.FLAG_DIM_BEHIND;
p.dimAmount = 0.3f;
wm.updateViewLayout(container, p);

Without background:

PopupWindow popup = new PopupWindow(contentView, width, height);
popup.setBackgroundDrawable(null);
popup.showAsDropDown(anchor);

WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
WindowManager.LayoutParams p = (WindowManager.LayoutParams) contentView.getLayoutParams();
// add flag
p.flags |= WindowManager.LayoutParams.FLAG_DIM_BEHIND;
p.dimAmount = 0.3f;
wm.updateViewLayout(contentView, p);

Marshmallow Update:

On M PopupWindow wraps the contentView inside a FrameLayout called mDecorView. If you dig into the PopupWindow source you will find something like createDecorView(View contentView).The main purpose of mDecorView is to handle event dispatch and content transitions, which are new to M. This means we need to add one more .getParent() to access the container.

With background that would require a change to something like:

View container = (View) popup.getContentView().getParent().getParent();

Better alternative for API 18+

A less hacky solution using ViewGroupOverlay:

1) Get a hold of the desired root layout

ViewGroup root = (ViewGroup) getWindow().getDecorView().getRootView();

2) Call applyDim(root, 0.5f); or clearDim()

public static void applyDim(@NonNull ViewGroup parent, float dimAmount){
    Drawable dim = new ColorDrawable(Color.BLACK);
    dim.setBounds(0, 0, parent.getWidth(), parent.getHeight());
    dim.setAlpha((int) (255 * dimAmount));

    ViewGroupOverlay overlay = parent.getOverlay();
    overlay.add(dim);
}

public static void clearDim(@NonNull ViewGroup parent) {
    ViewGroupOverlay overlay = parent.getOverlay();
    overlay.clear();
}

javascript: optional first argument in function

Like this:

my_function (null, options) // for options only
my_function (content) // for content only
my_function (content, options) // for both

Windows ignores JAVA_HOME: how to set JDK as default?

For my Case in 'Path' variable there was a parameter added like 'C:\ProgramData\Oracle\Java\javapath;'. This location was having java.exe, javaw.exe and javaws.exe from java 8 which is newly installed via jdk.exe from Oracle.

I've removed this text from Path where my Path already having %JAVA_HOME%\bin with it.

Now, the variable 'JAVA_HOME' is controlling my Java version which is I wanted.

Store mysql query output into a shell variable

You have the pipe the other way around and you need to echo the query, like this:

myvariable=$(echo "SELECT A, B, C FROM table_a" | mysql db -u $user -p $password)

Another alternative is to use only the mysql client, like this

myvariable=$(mysql db -u $user -p $password -se "SELECT A, B, C FROM table_a")

(-s is required to avoid the ASCII-art)

Now, BASH isn't the most appropriate language to handle this type of scenarios, especially handling strings and splitting SQL results and the like. You have to work a lot to get things that would be very, very simple in Perl, Python or PHP.

For example, how will you get each of A, B and C on their own variable? It's certainly doable, but if you do not understand pipes and echo (very basic shell stuff), it will not be an easy task for you to do, so if at all possible I'd use a better suited language.

Convert a string to datetime in PowerShell

$invoice = "Jul-16"
[datetime]$newInvoice = "01-" + $invoice

$newInvoice.ToString("yyyy-MM-dd")

There you go, use a type accelerator, but also into a new var, if you want to use it elsewhere, use it like so: $newInvoice.ToString("yyyy-MM-dd")as $newInvoice will always be in the datetime format, unless you cast it as a string afterwards, but will lose the ability to perform datetime functions - adding days etc...

What is the difference between "px", "dip", "dp" and "sp"?

Moreover you should have clear understanding about the following concepts:

Screen size:

Actual physical size, measured as the screen's diagonal. For simplicity, Android groups all actual screen sizes into four generalized sizes: small, normal, large, and extra large.

Screen density:

The quantity of pixels within a physical area of the screen; usually referred to as dpi (dots per inch). For example, a "low" density screen has fewer pixels within a given physical area, compared to a "normal" or "high" density screen. For simplicity, Android groups all actual screen densities into four generalized densities: low, medium, high, and extra high.

Orientation:

The orientation of the screen from the user's point of view. This is either landscape or portrait, meaning that the screen's aspect ratio is either wide or tall, respectively. Be aware that not only do different devices operate in different orientations by default, but the orientation can change at runtime when the user rotates the device.

Resolution:

The total number of physical pixels on a screen. When adding support for multiple screens, applications do not work directly with resolution; applications should be concerned only with screen size and density, as specified by the generalized size and density groups.

Density-independent pixel (dp):

A virtual pixel unit that you should use when defining UI layout, to express layout dimensions or position in a density-independent way. The density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a "medium" density screen. At runtime, the system transparently handles any scaling of the dp units, as necessary, based on the actual density of the screen in use. The conversion of dp units to screen pixels is simple: px = dp * (dpi / 160). For example, on a 240 dpi screen, 1 dp equals 1.5 physical pixels. You should always use dp units when defining your application's UI, to ensure proper display of your UI on screens with different densities.

Reference: Android developers site

Remove innerHTML from div

you should be able to just overwrite it without removing previous data

Redirect to an external URL from controller action in Spring MVC

You can use the RedirectView. Copied from the JavaDoc:

View that redirects to an absolute, context relative, or current request relative URL

Example:

@RequestMapping("/to-be-redirected")
public RedirectView localRedirect() {
    RedirectView redirectView = new RedirectView();
    redirectView.setUrl("http://www.yahoo.com");
    return redirectView;
}

You can also use a ResponseEntity, e.g.

@RequestMapping("/to-be-redirected")
public ResponseEntity<Object> redirectToExternalUrl() throws URISyntaxException {
    URI yahoo = new URI("http://www.yahoo.com");
    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders.setLocation(yahoo);
    return new ResponseEntity<>(httpHeaders, HttpStatus.SEE_OTHER);
}

And of course, return redirect:http://www.yahoo.com as mentioned by others.

Facebook share link without JavaScript

I know it's an old thread, but I had to do something like that for a project and I wanted to share the 2019 solution.

The new dialog API can get params and be used without any javascript.

The params are:

  • app_id (Required)
  • href The URL of the page you wish to share, in case none has passed will use the current URL.
  • hashtag have to have the # symbol for example #amsterdam
  • quote text to be shared with the link

You can create an href without any javascript what so ever.

_x000D_
_x000D_
<a href="https://www.facebook.com/dialog/feed?&app_id=APP_ID&link=URI&display=popup&quote=TEXT&hashtag=#HASHTAG" target="_blank">Share</a>
_x000D_
_x000D_
_x000D_

One thing to consider is that Facebook is using Open Graph so in case your OG tags are not set properly you might not get the results you wish for.

Disable the postback on an <ASP:LinkButton>

Something else you can do, if you want to preserve your scroll position is this:

<asp:LinkButton runat="server" id="someId" href="javascript: void;" Text="Click Me" />

pass array to method Java

You got a syntax wrong. Just pass in array's name. BTW - it's good idea to read some common formatting stuff too, for example in Java methods should start with lowercase letter (it's not an error it's convention)

How to go back (ctrl+z) in vi/vim

I had the same problem right now and i solved it. You must not need it anymore so I write for others:

if you use gvim on windows, you just add this in your _vimrc: $VIMRUNTIME/mswin.vim behave mswin

else just use imap...

Pointer to class data member "::*"

One way I've used it is if I have two implementations of how to do something in a class and I want to choose one at run-time without having to continually go through an if statement i.e.

class Algorithm
{
public:
    Algorithm() : m_impFn( &Algorithm::implementationA ) {}
    void frequentlyCalled()
    {
        // Avoid if ( using A ) else if ( using B ) type of thing
        (this->*m_impFn)();
    }
private:
    void implementationA() { /*...*/ }
    void implementationB() { /*...*/ }

    typedef void ( Algorithm::*IMP_FN ) ();
    IMP_FN m_impFn;
};

Obviously this is only practically useful if you feel the code is being hammered enough that the if statement is slowing things done eg. deep in the guts of some intensive algorithm somewhere. I still think it's more elegant than the if statement even in situations where it has no practical use but that's just my opnion.

how to find my angular version in my project?

try this command :

ng --version

It prints out Angular, Angular CLI, Node, Typescript versions etc.

Getting full URL of action in ASP.NET MVC

This what you need to do.

@Url.Action(action,controller, null, Request.Url.Scheme)

Set Content-Type to application/json in jsp file

Try this piece of code, it should work too

<%
    //response.setContentType("Content-Type", "application/json"); // this will fail compilation
    response.setContentType("application/json"); //fixed
%>

Reset all changes after last commit in git

There are two commands which will work in this situation,

root>git reset --hard HEAD~1

root>git push -f

For more git commands refer this page

How do I get the list of keys in a Dictionary?

To get list of all keys

using System.Linq;
List<String> myKeys = myDict.Keys.ToList();

System.Linq is supported in .Net framework 3.5 or above. See the below links if you face any issue in using System.Linq

Visual Studio Does not recognize System.Linq

System.Linq Namespace

Converting ISO 8601-compliant String to java.util.Date

After I searched a lot to convert ISO8601 to date I suddenly found a java class that is ISO8601Util.java and this was part of com.google.gson.internal.bind.util. So you can use it to convert dates.

ISO8601Utils.parse("2010-01-01T12:00:00Z" , ParsePosition(0))

and you can simply use this kotlin extension function

fun String.getDateFromString() : Date? = ISO8601Utils.parse(this , 
ParsePosition(0))

How can I use external JARs in an Android project?

If you are using gradle build system, follow these steps:

  1. put jar files inside respective libs folder of your android app. You will generally find it at Project > app > libs. If libs folder is missing, create one.

  2. add this to your build.gradle file your app. (Not to your Project's build.gradle)

    dependencies {
        compile fileTree(dir: 'libs', include: '*.jar')
        // other dependencies
    }
    

    This will include all your jar files available in libs folder.

If don't want to include all jar files, then you can add it individually.

compile fileTree(dir: 'libs', include: 'file.jar')

Sqlite in chrome

You can use Web SQL API which is an ordinary SQLite database in your browser and you can open/modify it like any other SQLite databases for example with Lita.

Chrome locates databases automatically according to domain names or extension id. A few months ago I posted on my blog short article on how to delete Chrome's database because when you're testing some functionality it's quite useful.

MySQL Multiple Left Joins

You're missing a GROUP BY clause:

SELECT news.id, users.username, news.title, news.date, news.body, COUNT(comments.id)
FROM news
LEFT JOIN users
ON news.user_id = users.id
LEFT JOIN comments
ON comments.news_id = news.id
GROUP BY news.id

The left join is correct. If you used an INNER or RIGHT JOIN then you wouldn't get news items that didn't have comments.

adding css class to multiple elements

.button input,
.button a {
    ...
}

"Expected an indented block" error?

I also experienced that for example:

This code doesnt work and get the intended block error.

class Foo(models.Model):
title = models.CharField(max_length=200)
body = models.TextField()
pub_date = models.DateTimeField('date published')
likes = models.IntegerField()

def __unicode__(self):
return self.title

However, when i press tab before typing return self.title statement, the code works.

class Foo(models.Model):
title = models.CharField(max_length=200)
body = models.TextField()
pub_date = models.DateTimeField('date published')
likes = models.IntegerField()

def __unicode__(self):
    return self.title

Hope, this will help others.

dropping rows from dataframe based on a "not in" condition

You can use Series.isin:

df = df[~df.datecolumn.isin(a)]

While the error message suggests that all() or any() can be used, they are useful only when you want to reduce the result into a single Boolean value. That is however not what you are trying to do now, which is to test the membership of every values in the Series against the external list, and keep the results intact (i.e., a Boolean Series which will then be used to slice the original DataFrame).

You can read more about this in the Gotchas.

How to colorize diff on the command line?

Coloured, word-level diff ouput

Here's what you can do with the the below script and diff-highlight:

Coloured diff screenshot

#!/bin/sh -eu

# Use diff-highlight to show word-level differences

diff -U3 --minimal "$@" |
  sed 's/^-/\x1b[1;31m-/;s/^+/\x1b[1;32m+/;s/^@/\x1b[1;34m@/;s/$/\x1b[0m/' |
  diff-highlight

(Credit to @retracile's answer for the sed highlighting)

How to set an HTTP proxy in Python 2.7?

You can install pip (or any other package) with easy_install almost as described in the first answer. However you will need a HTTPS proxy, too. The full sequence of commands is:

set http_proxy=http://proxy.myproxy.com
set https_proxy=http://proxy.myproxy.com
easy_install pip

You might also want to add a port to the proxy, such as http{s}_proxy=http://proxy.myproxy.com:8080

java.sql.SQLException: Fail to convert to internal representation

Your data types are mismatched when you are retrieving the field values. Check your code and ensure that for each field that you are retrieving that the java object matches that type. For example, retrieving a date into and int. If you are doing a select * then it is possible a change in the fields of the table has happened causing this error to occur. Your SQL should only select the fields you specifically want in order to avoid this error.

Hope this helps.

Java: Date from unix timestamp

This is the right way:

Date date = new Date ();
date.setTime((long)unix_time*1000);

How to change Maven local repository in eclipse

Here is settings.xml --> C:\maven\conf\settings.xml

How do I force Kubernetes to re-pull an image?

A popular workaround is to patch the deployment with a dummy annotation (or label):

kubectl patch deployment <name> -p \
  "{\"spec\":{\"template\":{\"metadata\":{\"annotations\":{\"date\":\"`date +'%s'`\"}}}}}"

Assuming your deployment meets these requirements, this will cause K8s to pull any new image and redeploy.

Better way to cast object to int

You can first cast object to string and then cast the string to int; for example:

string str_myobject = myobject.ToString();
int int_myobject = int.Parse(str_myobject);

this worked for me.

Math constant PI value in C

anyway you have not a unlimited accuracy so C define a constant in this way:

#define PI 3.14159265358979323846

import math.h to use this

Replace whitespace with a comma in a text file in Linux

without looking at your input file, only a guess

awk '{$1=$1}1' OFS=","

redirect to another file and rename as needed

Docker for Windows error: "Hardware assisted virtualization and data execution protection must be enabled in the BIOS"

Try this in PowerShell(admin enabled):

Enable-WindowsOptionalFeature –Online -FeatureName Microsoft-Hyper-V –All -NoRestart

This will install HyperVisor without management tools, and then you can run Docker after this.

Python string.join(list) on object array rather than string array

another solution is to override the join operator of the str class.

Let us define a new class my_string as follows

class my_string(str):
    def join(self, l):
        l_tmp = [str(x) for x in l]
        return super(my_string, self).join(l_tmp)

Then you can do

class Obj:
    def __str__(self):
        return 'name'

list = [Obj(), Obj(), Obj()]
comma = my_string(',')

print comma.join(list)

and you get

name,name,name

BTW, by using list as variable name you are redefining the list class (keyword) ! Preferably use another identifier name.

Hope you'll find my answer useful.

How to modify a specified commit?

Automated interactive rebase edit followed by commit revert ready for a do-over

I found myself fixing a past commit frequently enough that I wrote a script for it.

Here's the workflow:

  1. git commit-edit <commit-hash>
    

    This will drop you at the commit you want to edit.

  2. Fix and stage the commit as you wish it had been in the first place.

    (You may want to use git stash save to keep any files you're not committing)

  3. Redo the commit with --amend, eg:

    git commit --amend
    
  4. Complete the rebase:

    git rebase --continue
    

For the above to work, put the below script into an executable file called git-commit-edit somewhere in your $PATH:

#!/bin/bash

set -euo pipefail

script_name=${0##*/}

warn () { printf '%s: %s\n' "$script_name" "$*" >&2; }
die () { warn "$@"; exit 1; }

[[ $# -ge 2 ]] && die "Expected single commit to edit. Defaults to HEAD~"

# Default to editing the parent of the most recent commit
# The most recent commit can be edited with `git commit --amend`
commit=$(git rev-parse --short "${1:-HEAD~}")
message=$(git log -1 --format='%h %s' "$commit")

if [[ $OSTYPE =~ ^darwin ]]; then
  sed_inplace=(sed -Ei "")
else
  sed_inplace=(sed -Ei)
fi

export GIT_SEQUENCE_EDITOR="${sed_inplace[*]} "' "s/^pick ('"$commit"' .*)/edit \\1/"'
git rebase --quiet --interactive --autostash --autosquash "$commit"~
git reset --quiet @~ "$(git rev-parse --show-toplevel)"  # Reset the cache of the toplevel directory to the previous commit
git commit --quiet --amend --no-edit --allow-empty  #  Commit an empty commit so that that cache diffs are un-reversed

echo
echo "Editing commit: $message" >&2
echo

"git pull" or "git merge" between master and development branches

my rule of thumb is:

rebase for branches with the same name, merge otherwise.

examples for same names would be master, origin/master and otherRemote/master.

if develop exists only in the local repository, and it is always based on a recent origin/master commit, you should call it master, and work there directly. it simplifies your life, and presents things as they actually are: you are directly developing on the master branch.

if develop is shared, it should not be rebased on master, just merged back into it with --no-ff. you are developing on develop. master and develop have different names, because we want them to be different things, and stay separate. do not make them same with rebase.

Generating Unique Random Numbers in Java

This will work to generate unique random numbers................

import java.util.HashSet;
import java.util.Random;

public class RandomExample {

    public static void main(String[] args) {
        Random rand = new Random();
        int e;
        int i;
        int g = 10;
        HashSet<Integer> randomNumbers = new HashSet<Integer>();

        for (i = 0; i < g; i++) {
            e = rand.nextInt(20);
            randomNumbers.add(e);
            if (randomNumbers.size() <= 10) {
                if (randomNumbers.size() == 10) {
                    g = 10;
                }
                g++;
                randomNumbers.add(e);
            }
        }
        System.out.println("Ten Unique random numbers from 1 to 20 are  : " + randomNumbers);
    }
}

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

UPDATE 2015/08/26:

If you don't want to use deprecated HttpEntity, here is my working sample code (tested with ASP.Net WebAPI)

MultipartActivity.java

package com.example.volleyapp;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.view.Menu;
import android.view.MenuItem;

import com.android.volley.AuthFailureError;
import com.android.volley.NetworkResponse;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.example.volleyapp.BaseVolleyRequest;
import com.example.volleyapp.VolleySingleton;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;

public class MultipartActivity extends Activity {

    final Context mContext = this;
    String mimeType;
    DataOutputStream dos = null;
    String lineEnd = "\r\n";
    String boundary = "apiclient-" + System.currentTimeMillis();
    String twoHyphens = "--";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
    int maxBufferSize = 1024 * 1024;

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

        Drawable drawable = ContextCompat.getDrawable(mContext, R.drawable.ic_action_file_attachment_light);
        Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, byteArrayOutputStream);
        final byte[] bitmapData = byteArrayOutputStream.toByteArray();
        String url = "http://192.168.1.100/api/postfile";

        mimeType = "multipart/form-data;boundary=" + boundary;

        BaseVolleyRequest baseVolleyRequest = new BaseVolleyRequest(1, url, new Response.Listener<NetworkResponse>() {
            @Override
            public void onResponse(NetworkResponse response) {

            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

            }
        }) {
            @Override
            public String getBodyContentType() {
                return mimeType;
            }

            @Override
            public byte[] getBody() throws AuthFailureError {
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                dos = new DataOutputStream(bos);
                try {
                    dos.writeBytes(twoHyphens + boundary + lineEnd);
                    dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
                            + "ic_action_file_attachment_light.png" + "\"" + lineEnd);
                    dos.writeBytes(lineEnd);
                    ByteArrayInputStream fileInputStream = new ByteArrayInputStream(bitmapData);
                    bytesAvailable = fileInputStream.available();

                    bufferSize = Math.min(bytesAvailable, maxBufferSize);
                    buffer = new byte[bufferSize];

                    // read file and write it into form...
                    bytesRead = fileInputStream.read(buffer, 0, bufferSize);

                    while (bytesRead > 0) {
                        dos.write(buffer, 0, bufferSize);
                        bytesAvailable = fileInputStream.available();
                        bufferSize = Math.min(bytesAvailable, maxBufferSize);
                        bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                    }

                    // send multipart form data necesssary after file data...
                    dos.writeBytes(lineEnd);
                    dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

                    return bos.toByteArray();

                } catch (IOException e) {
                    e.printStackTrace();
                }
                return bitmapData;
            }
        };

        VolleySingleton.getInstance(mContext).addToRequestQueue(baseVolleyRequest);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_multipart, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

BaseVolleyRequest.java:

package com.example.volleyapp;

import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.HttpHeaderParser;
import com.google.gson.JsonSyntaxException;


public class BaseVolleyRequest extends Request<NetworkResponse> {

    private final Response.Listener<NetworkResponse> mListener;
    private final Response.ErrorListener mErrorListener;

    public BaseVolleyRequest(String url, Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
        super(0, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
    }

    public BaseVolleyRequest(int method, String url, Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
    }

    @Override
    protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
        try {
            return Response.success(
                    response,
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (JsonSyntaxException e) {
            return Response.error(new ParseError(e));
        } catch (Exception e) {
            return Response.error(new ParseError(e));
        }
    }

    @Override
    protected void deliverResponse(NetworkResponse response) {
        mListener.onResponse(response);
    }

    @Override
    protected VolleyError parseNetworkError(VolleyError volleyError) {
        return super.parseNetworkError(volleyError);
    }

    @Override
    public void deliverError(VolleyError error) {
        mErrorListener.onErrorResponse(error);
    }
}

END OF UPDATE

This is my working sample code (only tested with small-size files):

public class FileUploadActivity extends Activity {

    private final Context mContext = this;
    HttpEntity httpEntity;

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

        Drawable drawable = getResources().getDrawable(R.drawable.ic_action_home);
        if (drawable != null) {
            Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
            final byte[] bitmapdata = stream.toByteArray();
            String url = "http://10.0.2.2/api/fileupload";
            MultipartEntityBuilder builder = MultipartEntityBuilder.create();
            builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);

            // Add binary body
            if (bitmapdata != null) {
                ContentType contentType = ContentType.create("image/png");
                String fileName = "ic_action_home.png";
                builder.addBinaryBody("file", bitmapdata, contentType, fileName);
                httpEntity = builder.build();

                MyRequest myRequest = new MyRequest(Request.Method.POST, url, new Response.Listener<NetworkResponse>() {
                    @Override
                    public void onResponse(NetworkResponse response) {
                        try {                            
                            String jsonString = new String(response.data,
                                    HttpHeaderParser.parseCharset(response.headers));
                            Toast.makeText(mContext, jsonString, Toast.LENGTH_SHORT).show();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(mContext, error.toString(), Toast.LENGTH_SHORT).show();                        
                    }
                }) {
                    @Override
                    public String getBodyContentType() {
                        return httpEntity.getContentType().getValue();
                    }

                    @Override
                    public byte[] getBody() throws AuthFailureError {
                        ByteArrayOutputStream bos = new ByteArrayOutputStream();
                        try {
                            httpEntity.writeTo(bos);
                        } catch (IOException e) {
                            VolleyLog.e("IOException writing to ByteArrayOutputStream");
                        }
                        return bos.toByteArray();
                    }
                };

                MySingleton.getInstance(this).addToRequestQueue(myRequest);
            }
        }
    }

    ...
}

public class MyRequest extends Request<NetworkResponse>

How to change a dataframe column from String type to Double type in PySpark?

There is no need for an UDF here. Column already provides cast method with DataType instance :

from pyspark.sql.types import DoubleType

changedTypedf = joindf.withColumn("label", joindf["show"].cast(DoubleType()))

or short string:

changedTypedf = joindf.withColumn("label", joindf["show"].cast("double"))

where canonical string names (other variations can be supported as well) correspond to simpleString value. So for atomic types:

from pyspark.sql import types 

for t in ['BinaryType', 'BooleanType', 'ByteType', 'DateType', 
          'DecimalType', 'DoubleType', 'FloatType', 'IntegerType', 
           'LongType', 'ShortType', 'StringType', 'TimestampType']:
    print(f"{t}: {getattr(types, t)().simpleString()}")
BinaryType: binary
BooleanType: boolean
ByteType: tinyint
DateType: date
DecimalType: decimal(10,0)
DoubleType: double
FloatType: float
IntegerType: int
LongType: bigint
ShortType: smallint
StringType: string
TimestampType: timestamp

and for example complex types

types.ArrayType(types.IntegerType()).simpleString()   
'array<int>'
types.MapType(types.StringType(), types.IntegerType()).simpleString()
'map<string,int>'

How to remove items from a list while iterating?

For those that like functional programming:

somelist[:] = filter(lambda tup: not determine(tup), somelist)

or

from itertools import ifilterfalse
somelist[:] = list(ifilterfalse(determine, somelist))

How to get an Android WakeLock to work?

I am having a similar problem. I can get the screen to stay on, but if I use a partial wake lock and the screen is turned off, my onFinish function isn't called until the screen is turned on.

You can check your wake lock using mWakeLock.isHeld(), first of all, to make sure you're getting it. Easiest way is to add that to the code, set a breakpoint on it in the debugger, and then check it.

In my case, I'm getting it, but the partial wake lock doesn't seem to be doing anything. Here's my working code for the screen dim lock.

protected void setScreenLock(boolean on){
        if(mWakeLock == null){
            PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
            mWakeLock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK |
                                        PowerManager.ON_AFTER_RELEASE, TAG);
        }
        if(on){
         mWakeLock.acquire();
        }else{
            if(mWakeLock.isHeld()){
                mWakeLock.release();
            }
         mWakeLock = null;
        }

    }

ADDENDUM:

Droid Eris and DROID users are reporting to me that this DOES NOT work on their devices, though it works fine on my G1. What device are you testing on? I think this may be an Android bug.

C# importing class into another class doesn't work

If they are separate class files within the same project, then you do not need to have an 'import' statement. Just use the class straight off. If the files are in separate projects, you need to add a reference to the project first before you can use an 'import' statement on it.

Schema validation failed with the following errors: Data path ".builders['app-shell']" should have required property 'class'

I have to say, if you don't want to change anything in package.json file, try to update your Node.js version to latest. (currently 12.13.1 LTS)

get the value of DisplayName attribute

PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(foo);

foreach (PropertyDescriptor property in properties)
{
    if (property.Name == "Name")
    {
        Console.WriteLine(property.DisplayName); // Something To Name
    }
}

where foo is an instance of Class1

Disable and enable buttons in C#

Update 2019

This is now IsEnabled

 takePicturebutton.IsEnabled = false; // true

Create a custom View by inflating a layout?

A bit old, but I thought sharing how I'd do it, based on chubbsondubs' answer: I use FrameLayout (see Documentation), since it is used to contain a single view, and inflate into it the view from the xml.

Code following:

public class MyView extends FrameLayout {
    public MyView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initView();
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView();
    }

    public MyView(Context context) {
        super(context);
        initView();
    }

    private void initView() {
        inflate(getContext(), R.layout.my_view_layout, this);
    }
}

Extract file name from path, no matter what the os/path format

My personal favourite is:

filename = fullname.split(os.sep)[-1]

How to close a window using jQuery

For IE: window.close(); and self.close(); should work fine.

If you want just open the IE browser and type

javascript:self.close() and hit enter, it should ask you for a prompt.

Note: this method doesn't work for Chrome or Firefox.

VBScript: Using WScript.Shell to Execute a Command Line Program That Accesses Active Directory

When you run WScript.Shell it runs under the local system account, this account has full rights on the machine, but no rights in Active Directory.

http://support.microsoft.com/kb/278319

Truncate a string straight JavaScript

var str = "Anything you type in.";
str.substring(0, 5) + "..." //you can type any amount of length you want

Which encoding opens CSV files correctly with Excel on both Mac and Windows?

instead of csv, trying outputting html with an XLS extension and "application/excel" mime-type. I know this will work in Windows, but can't speak for MacOS

Get the first element of an array

PHP 5.4+:

array_values($array)[0];

How to save .xlsx data to file as a blob

Solution for me.

Step: 1

<a onclick="exportAsExcel()">Export to excel</a>

Step: 2

I'm using file-saver lib.

Read more: https://www.npmjs.com/package/file-saver

npm i file-saver

Step: 3

let FileSaver = require('file-saver'); // path to file-saver

function exportAsExcel() {
    let dataBlob = '...kAAAAFAAIcmtzaGVldHMvc2hlZXQxLnhtbFBLBQYAAAAACQAJAD8CAADdGAAAAAA='; // If have ; You should be split get blob data only
    this.downloadFile(dataBlob);
}

function downloadFile(blobContent){
    let blob = new Blob([base64toBlob(blobContent, 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')], {});
    FileSaver.saveAs(blob, 'report.xlsx');
}

function base64toBlob(base64Data, contentType) {
    contentType = contentType || '';
    let sliceSize = 1024;
    let byteCharacters = atob(base64Data);
    let bytesLength = byteCharacters.length;
    let slicesCount = Math.ceil(bytesLength / sliceSize);
    let byteArrays = new Array(slicesCount);
    for (let sliceIndex = 0; sliceIndex < slicesCount; ++sliceIndex) {
        let begin = sliceIndex * sliceSize;
        let end = Math.min(begin + sliceSize, bytesLength);

        let bytes = new Array(end - begin);
        for (var offset = begin, i = 0; offset < end; ++i, ++offset) {
            bytes[i] = byteCharacters[offset].charCodeAt(0);
        }
        byteArrays[sliceIndex] = new Uint8Array(bytes);
    }
    return new Blob(byteArrays, { type: contentType });
}

Work for me. ^^

how to open .mat file without using MATLAB?

There's a really nice easy way to do this in Macintosh OsX. A fellow has made a quicklook plugin (command-space) that renders .mat formats so you can view the variables inside etc. Quite useful! https://github.com/jaketmp/matlab-quicklook/releases

how to fix stream_socket_enable_crypto(): SSL operation failed with code 1

How to fix on Laravel 7:

Download the latest cacert.pem file from cURL website.

wget https://curl.haxx.se/ca/cacert.pem

Edit php.ini (you can do php --ini to find it), update (or create if they don't exist already) those two lines:

curl.cainfo="/path/to/downloaded/cacert.pem"
...
openssl.cafile="/path/to/downloaded/cacert.pem"

Those lines should already exist but commented out, so uncomment them and edit both values with the path to the downloaded cacert.pem

Restart PHP and Nginx/Apache.

Edit: You may need to chown/chmod the downloaded certificate file so PHP (and its user) can read it.

source

How to check if variable is array?... or something array-like

You can check instance of Traversable with a simple function. This would work for all this of Iterator because Iterator extends Traversable

function canLoop($mixed) {
    return is_array($mixed) || $mixed instanceof Traversable ? true : false;
}

Using File.listFiles with FileNameExtensionFilter

One-liner in java 8 syntax:

pdfTestDir.listFiles((dir, name) -> name.toLowerCase().endsWith(".txt"));

No such keg: /usr/local/Cellar/git

Give another go at force removing the brewed version of git

brew uninstall --force git

Then cleanup any older versions and clear the brew cache

brew cleanup -s git

Remove any dead symlinks

brew cleanup --prune-prefix

Then try reinstalling git

brew install git

If that doesn't work, I'd remove that installation of Homebrew altogether and reinstall it. If you haven't placed anything else in your brew --prefix directory (/usr/local by default), you can simply rm -rf $(brew --prefix). Otherwise the Homebrew wiki recommends using a script at https://gist.github.com/mxcl/1173223#file-uninstall_homebrew-sh

How do I remove whitespace from the end of a string in Python?

You can use strip() or split() to control the spaces values as in the following:

words = "   first  second   "

# Remove end spaces
def remove_end_spaces(string):
    return "".join(string.rstrip())


# Remove the first and end spaces
def remove_first_end_spaces(string):
    return "".join(string.rstrip().lstrip())


# Remove all spaces
def remove_all_spaces(string):
    return "".join(string.split())


# Show results
print(words)
print(remove_end_spaces(words))
print(remove_first_end_spaces(words))
print(remove_all_spaces(words))

Using $_POST to get select option value from HTML

<select name="taskOption">
<option value="1">First</option>
<option value="2">Second</option>
<option value="3">Third</option>
</select>

try this

<?php 
if(isset($_POST['button_name'])){
$var = $_POST['taskOption']
if($var == "1"){
echo"your data here";
}
}?>

How to detect a mobile device with JavaScript?

Since it's now 2015, if you stumbled across this question then you should probably be using window.matchMedia (and, if it's still 2015, polyfilling for older browsers):

if (matchMedia('handheld').matches) {
    //...
} else {
    //...
}

I'm trying to use python in powershell

To be able to use Python immediately without restarting the shell window you need to change the path for the machine, the process and the user.

Function Get-EnvVariableNameList {
    [cmdletbinding()]
    $allEnvVars = Get-ChildItem Env:
    $allEnvNamesArray = $allEnvVars.Name
    $pathEnvNamesList = New-Object System.Collections.ArrayList
    $pathEnvNamesList.AddRange($allEnvNamesArray)
    return ,$pathEnvNamesList
}

Function Add-EnvVarIfNotPresent {
Param (
[string]$variableNameToAdd,
[string]$variableValueToAdd
   ) 
    $nameList = Get-EnvVariableNameList
    $alreadyPresentCount = ($nameList | Where{$_ -like $variableNameToAdd}).Count
    #$message = ''
    if ($alreadyPresentCount -eq 0)
    {
    [System.Environment]::SetEnvironmentVariable($variableNameToAdd, $variableValueToAdd, [System.EnvironmentVariableTarget]::Machine)
    [System.Environment]::SetEnvironmentVariable($variableNameToAdd, $variableValueToAdd, [System.EnvironmentVariableTarget]::Process)
    [System.Environment]::SetEnvironmentVariable($variableNameToAdd, $variableValueToAdd, [System.EnvironmentVariableTarget]::User)
        $message = "Enviromental variable added to machine, process and user to include $variableNameToAdd"
    }
    else
    {
        $message = 'Environmental variable already exists. Consider using a different function to modify it'
    }
    Write-Information $message
}


Function Get-EnvExtensionList {
    $pathExtArray =  ($env:PATHEXT).Split("{;}")
    $pathExtList = New-Object System.Collections.ArrayList
    $pathExtList.AddRange($pathExtArray)
    return ,$pathExtList
}


Function Add-EnvExtension {
Param (
[string]$pathExtToAdd
   ) 
    $pathList = Get-EnvExtensionList
    $alreadyPresentCount = ($pathList | Where{$_ -like $pathToAdd}).Count
    if ($alreadyPresentCount -eq 0)
    {
        $pathList.Add($pathExtToAdd)
        $returnPath = $pathList -join ";"
        [System.Environment]::SetEnvironmentVariable('pathext', $returnPath, [System.EnvironmentVariableTarget]::Machine)
        [System.Environment]::SetEnvironmentVariable('pathext', $returnPath, [System.EnvironmentVariableTarget]::Process)
        [System.Environment]::SetEnvironmentVariable('pathext', $returnPath, [System.EnvironmentVariableTarget]::User)
        $message = "Path extension added to machine, process and user paths to include $pathExtToAdd"
    }
    else
    {
        $message = 'Path extension already exists'
    }
    Write-Information $message
}

Function Get-EnvPathList {
    [cmdletbinding()]
    $pathArray =  ($env:PATH).Split("{;}")
    $pathList = New-Object System.Collections.ArrayList
    $pathList.AddRange($pathArray)
    return ,$pathList
}

Function Add-EnvPath {
Param (
[string]$pathToAdd
   ) 
    $pathList = Get-EnvPathList
    $alreadyPresentCount = ($pathList | Where{$_ -like $pathToAdd}).Count
    if ($alreadyPresentCount -eq 0)
    {
        $pathList.Add($pathToAdd)
        $returnPath = $pathList -join ";"
        [System.Environment]::SetEnvironmentVariable('path', $returnPath, [System.EnvironmentVariableTarget]::Machine)
        [System.Environment]::SetEnvironmentVariable('path', $returnPath, [System.EnvironmentVariableTarget]::Process)
        [System.Environment]::SetEnvironmentVariable('path', $returnPath, [System.EnvironmentVariableTarget]::User)
        $message = "Path added to machine, process and user paths to include $pathToAdd"
    }
    else
    {
        $message = 'Path already exists'
    }
    Write-Information $message
}

Add-EnvExtension '.PY'
Add-EnvExtension '.PYW'
Add-EnvPath 'C:\Python27\'

Debugging the error "gcc: error: x86_64-linux-gnu-gcc: No such file or directory"

sudo apt-get -y install python-software-properties && \
sudo apt-get -y install software-properties-common && \
sudo apt-get -y install gcc make build-essential libssl-dev libffi-dev python-dev

You need the libssl-dev and libffi-dev if especially you are trying to install python's cryptography libraries or python libs that depend on it(eg ansible)

Tensorflow set CUDA_VISIBLE_DEVICES within jupyter

You can do it faster without any imports just by using magics:

%env CUDA_DEVICE_ORDER=PCI_BUS_ID
%env CUDA_VISIBLE_DEVICES=0

Notice that all env variable are strings, so no need to use ". You can verify that env-variable is set up by running: %env <name_of_var>. Or check all of them with %env.

Android failed to load JS bundle

After trying out a combination of the answers here, this is what is working for me.

I'm using Genymotion as my emulator.

1 Start up Genymotion emulator.

2 From a terminal

cd AwesomeProject
react-native run-android # it loads in genymotion and fails with bundle error
react-native start > /dev/null 2>&1 & # from dsissitka
adb reverse tcp:8081 tcp:8081 # from dsissitka

3 Reload from emulator.

It loads!

I can now begin developing.

reading from app.config file

Try:

string value = ConfigurationManager.AppSettings[key];

For more details check: Reading Keys from App.Config

How can I convert an Integer to localized month name in Java?

I would use SimpleDateFormat. Someone correct me if there is an easier way to make a monthed calendar though, I do this in code now and I'm not so sure.

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;


public String formatMonth(int month, Locale locale) {
    DateFormat formatter = new SimpleDateFormat("MMMM", locale);
    GregorianCalendar calendar = new GregorianCalendar();
    calendar.set(Calendar.DAY_OF_MONTH, 1);
    calendar.set(Calendar.MONTH, month-1);
    return formatter.format(calendar.getTime());
}

Copy an entire worksheet to a new worksheet in Excel 2010

' Assume that the code name the worksheet is Sheet1

' Copy the sheet using code name and put in the end.
' Note: Using the code name lets the user rename the worksheet without breaking the VBA code
Sheet1.Copy After:=Sheets(Sheets.Count)

' Rename the copied sheet keeping the same name and appending a string " copied"
ActiveSheet.Name = Sheet1.Name & " copied"

How to change btn color in Bootstrap

You can add custom colors using bootstrap theming in your config file for example variables.scss and make sure you import that file before bootstrap when compiling.

$theme-colors: (
    "whatever": #900
);

Now you can do .btn-whatever

ASP.NET strange compilation error

I had this error message and for me the solution was to install Dot Net Framework 4.6 ,While my project targeted 4.5.2

What is the "Temporary ASP.NET Files" folder for?

The CLR uses it when it is compiling at runtime. Here is a link to MSDN that explains further.

Visual Studio 2017 - Git failed with a fatal error

AngelBlueSky's answer worked partially for me. I had to execute these additional lines to clean the Git global configuration after step 4:

git config --global credential.helper wincred
git config http.sslcainfo "C:/Program Files/Git/mingw64/ssl/certs/ca-bundle.crt"
git config --global --unset core.askpass
git config --global --unset mergetool.vsdiffmerge.keepbackup
git config --global --unset mergetool.vsdiffmerge.trustexitcode
git config --global --unset mergetool.vsdiffmerge.cmd
git config --global --unset mergetool.prompt
git config --global --unset merge.tool
git config --global --unset difftool.vsdiffmerge.keepbackup
git config --global --unset difftool.vsdiffmerge.cmd
git config --global --unset difftool.prompt
git config --global --unset diff.tool

Then git config -l (executed from any git repo) should return only this:

core.symlinks=false
core.autocrlf=false
core.fscache=true
color.diff=auto
color.status=auto
color.branch=auto
color.interactive=true
help.format=html
diff.astextplain.textconv=astextplain
rebase.autosquash=true
user.name=xxxxxxxxxxxx
[email protected]
credential.helper=wincred
core.bare=false
core.filemode=false
core.symlinks=false
core.ignorecase=true
core.logallrefupdates=true
core.repositoryformatversion=0
remote.origin.url=https://[email protected]/xxx/xxx.git
remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
branch.master.remote=origin
branch.master.merge=refs/heads/master
branch.identityserver.remote=origin
branch.identityserver.merge=refs/heads/identityserver
http.sslcainfo=C:/Program Files/Git/mingw64/ssl/certs/ca-bundle.crt

Run the git status and git fetch commands to validate that it works from the command line.

Then go to Visual Studio, where your repositories should be back, and all sync/push/pull should work without issues.

What does %s and %d mean in printf in the C language?

%d is print as an int %s is print as a string %f is print as floating point

It should be noted that it is incorrect to say that this is different from Java. Printf stands for print format, if you do a formatted print in Java, this is exactly the same usage. This may allow you to solve interesting and new problems in both C and Java!

What is the purpose of meshgrid in Python / NumPy?

Short answer

The purpose of meshgrid is to help remplace Python loops (slow interpreted code) by vectorized operations within C NumPy library.

Borrowed from this site.

enter image description here

x = np.arange(-4, 4, 0.25)
y = np.arange(-4, 4, 0.25)
X, Y = np.meshgrid(x, y)
R = np.sqrt(X**2 + Y**2)
Z = np.sin(R)

meshgrid is used to create pairs of coordinates between -4 and +4 with .25 increments in each direction X and Y. Each pair is then used to find R, and Z from it. This way of preparing "a grid" of coordinates is frequently used in plotting 3D surfaces, or coloring 2D surfaces.


Details: Python for-loop vs NumPy vector operation

To take a more simple example, let's say we have two sequences of values,

a = [2,7,9,20]    
b = [1,6,7,9]    ?

and we want to perform an operation on each possible pair of values, one taken from the first list, one taken from the second list. We also want to store the result. For example, let's say we want to get the sum of the values for each possible pair.

Slow and laborious method

c = []    
for i in range(len(b)):    
    row = []    
    for j in range(len(a)):    
        row.append (a[j] + b[i])
    c.append (row)    
print (c)

Result:

[[3, 8, 10, 21],
 [8, 13, 15, 26],
 [9, 14, 16, 27],
 [11, 16, 18, 29]]

Python is interpreted, these loops are relatively slow to execute.

Fast and easy method

meshgrid is intended to remove the loops from the code. It returns two arrays (i and j below) which can be combined to scan all the existing pairs like this:

i,j = np.meshgrid (a,b)    
c = i + j    
print (c)

Result:

[[ 3  8 10 21]
 [ 8 13 15 26]
 [ 9 14 16 27]
 [11 16 18 29]]

Meshgrid under the hood

The two arrays prepared by meshgrid are:

(array([[ 2,  7,  9, 20],
        [ 2,  7,  9, 20],
        [ 2,  7,  9, 20],
        [ 2,  7,  9, 20]]),

 array([[1, 1, 1, 1],
        [6, 6, 6, 6],
        [7, 7, 7, 7],
        [9, 9, 9, 9]]))

These arrays are created by repeating the values provided. One contains the values in identical rows, the other contains the other values in identical columns. The number of rows and column is determined by the number of elements in the other sequence.

The two arrays created by meshgrid are therefore shape compatible for a vector operation. Imagine x and y sequences in the code at the top of page having a different number of elements, X and Y resulting arrays will be shape compatible anyway, not requiring any broadcast.

Origin

numpy.meshgrid comes from MATLAB, like many other NumPy functions. So you can also study the examples from MATLAB to see meshgrid in use, the code for the 3D plotting looks the same in MATLAB.

Exporting data In SQL Server as INSERT INTO

Here is an example of creating a data migration script using a cursor to iterate the source table.

SET NOCOUNT ON;  
DECLARE @out nvarchar(max) = ''
DECLARE @row nvarchar(1024)
DECLARE @first int = 1

DECLARE cur CURSOR FOR 
    SELECT '(' + CONVERT(CHAR(1),[Stage]) + ',''' + [Label] + ''')'
    FROM CV_ORDER_STATUS
    ORDER BY [Stage]

PRINT 'SET IDENTITY_INSERT dbo.CV_ORDER_STATUS ON'
PRINT 'GO'

PRINT 'INSERT INTO dbo.CV_ORDER_STATUS ([Stage],[Label]) VALUES';

OPEN cur
FETCH NEXT FROM cur
    INTO @row

WHILE @@FETCH_STATUS = 0
BEGIN
    IF @first = 1
        SET @first = 0
    ELSE
        SET @out = @out + ',' + CHAR(13);

    SET @out = @out + @row

    FETCH NEXT FROM cur into @row
END

CLOSE cur
DEALLOCATE cur

PRINT @out

PRINT 'SET IDENTITY_INSERT dbo.CV_ORDER_STATUS OFF'
PRINT 'GO'

Passing array in GET for a REST call

Instead of using http GET, use http POST. And JSON. Or XML

This is how your request stream to the server would look like.

POST /appointments HTTP/1.0
Content-Type: application/json
Content-Length: (calculated by your utility)

{users: [user:{id:id1}, user:{id:id2}]}

Or in XML,

POST /appointments HTTP/1.0
Content-Type: application/json
Content-Length: (calculated by your utility)

<users><user id='id1'/><user id='id2'/></users>

You could certainly continue using GET as you have proposed, as it is certainly simpler.

/appointments?users=1d1,1d2

Which means you would have to keep your data structures very simple.

However, if/when your data structure gets more complex, http GET and without JSON, your programming and ability to recognise the data gets very difficult.

Therefore,unless you could keep your data structure simple, I urge you adopt a data transfer framework. If your requests are browser based, the industry usual practice is JSON. If your requests are server-server, than XML is the most convenient framework.

JQuery

If your client is a browser and you are not using GWT, you should consider using jquery REST. Google on RESTful services with jQuery.

Rails: update_attribute vs update_attributes

To answer your question, update_attribute skips pre save "validations" but it still runs any other callbacks like after_save etc. So if you really want to "just update the column and skip any AR cruft" then you need to use (apparently)

Model.update_all(...) see https://stackoverflow.com/a/7243777/32453

'cannot open git-upload-pack' error in Eclipse when cloning or pushing git repository

I just got this same error, "cannot open git-upload-pack", in Eclipse with a BitBucket repo trying to do a pull or a push. I resolved it by switching local branches (Team/Switch To) to the master branch and doing a pull, and then switching back to the branch I was working on and pulling again.

How can I verify a Google authentication API access token?

I need to somehow query Google and ask: Is this access token valid for [email protected]?

No. All you need is request standard login with Federated Login for Google Account Users from your API domain. And only after that you could compare "persistent user ID" with one you have from 'public interface'.

The value of realm is used on the Google Federated Login page to identify the requesting site to the user. It is also used to determine the value of the persistent user ID returned by Google.

So you need be from same domain as 'public interface'.

And do not forget that user needs to be sure that your API could be trusted ;) So Google will ask user if it allows you to check for his identity.

How to stick a footer to bottom in css?

For modern browser, you can use flex layout to ensure the footer stays at the bottom no matter the content length (and the bottom won't hide the content if it is too long)

HTML Layout:

<div class="layout-wrapper">
  <header>My header</header>
  <section class="page-content">My Main page content</section>
  <footer>My footer</footer>
</div>

CSS:

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

.layout-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.layout-wrapper > .page-content {
  background: cornflowerblue;
  color: white;
  padding: 20px;
}

.layout-wrapper > header, .layout-wrapper > footer {
  background: #C0C0C0;
  padding: 20px 0;
}

Demo: https://codepen.io/datvm/pen/vPWXOQ

Find ALL tweets from a user (not just the first 3,200)

The only way to see more is to start saving them before the user's tweet count hits 3200. Services which show more than 3200 tweets have saved them in their own dbs. There's currently no way to get more than that through any Twitter API.

http://www.quora.com/Is-there-a-way-to-get-more-than-3200-tweets-from-a-twitter-user-using-Twitters-API-or-scraping

https://dev.twitter.com/discussions/276

Note from that second link: "…the 3,200 limit is for browsing the timeline only. Tweets can always be requested by their ID using the GET statuses/show/:id method."

Unable to make the session state request to the session state server

Check that:

stateConnectionString="tcpip=server:port"

is correct. Also please check that default port (42424) is available and your system does not have a firewall that is blocking the port on your system

Is there a naming convention for MySQL?

MySQL has a short description of their more or less strict rules:

https://dev.mysql.com/doc/internals/en/coding-style.html

Most common codingstyle for MySQL by Simon Holywell:

http://www.sqlstyle.guide/

See also this question: Are there any published coding style guidelines for SQL?

Bundler::GemNotFound: Could not find rake-10.3.2 in any of the sources

Remove your Gemfile.lock.

Move to bash if you are using zsh.

sudo bash
gem update --system 

Now run command bundle to create a new Gemfile.lock file. Move back to your zsh sudo exec zsh now run your rake commands.

How to check for null in a single statement in scala?

Try to avoid using null in Scala. It's really there only for interoperability with Java. In Scala, use Option for things that might be empty. If you're calling a Java API method that might return null, wrap it in an Option immediately.

def getObject : Option[QueueObject] = {
  // Wrap the Java result in an Option (this will become a Some or a None)
  Option(someJavaObject.getResponse)
}

Note: You don't need to put it in a val or use an explicit return statement in Scala; the result will be the value of the last expression in the block (in fact, since there's only one statement, you don't even need a block).

def getObject : Option[QueueObject] = Option(someJavaObject.getResponse)

Besides what the others have already shown (for example calling foreach on the Option, which might be slightly confusing), you could also call map on it (and ignore the result of the map operation if you don't need it):

getObject map QueueManager.add

This will do nothing if the Option is a None, and call QueueManager.add if it is a Some.

I find using a regular if however clearer and simpler than using any of these "tricks" just to avoid an indentation level. You could also just write it on one line:

if (getObject.isDefined) QueueManager.add(getObject.get)

or, if you want to deal with null instead of using Option:

if (getObject != null) QueueManager.add(getObject)

edit - Ben is right, be careful to not call getObject more than once if it has side-effects; better write it like this:

val result = getObject
if (result.isDefined) QueueManager.add(result.get)

or:

val result = getObject
if (result != null) QueueManager.add(result)

Warning: DOMDocument::loadHTML(): htmlParseEntityRef: expecting ';' in Entity,

Another possibile solution is,maybe your file is ASCII type file,just change the type of your files.

convert htaccess to nginx

Online tools to translate Apache .htaccess to Nginx rewrite tools include:

Note that these tools will convert to equivalent rewrite expressions using if statements, but they should be converted to try_files. See:

UITableView - change section header color

For iOS8 (Beta) and Swift choose the RGB Color you want and try this:

override func tableView(tableView: UITableView!, viewForHeaderInSection section: Int) -> UIView! {
    var header :UITableViewHeaderFooterView = UITableViewHeaderFooterView()

    header.contentView.backgroundColor = UIColor(red: 254.0/255.0, green: 190.0/255.0, blue: 127.0/255.0, alpha: 1)
    return header

}

(The "override" is there since i´m using the UITableViewController instead of a normal UIViewController in my project, but it´s not mandatory for changing the section header color)

The text of your header will still be seen. Note that you will need to adjust the section header height.

Good Luck.

ObservableCollection Doesn't support AddRange method, so I get notified for each item added, besides what about INotifyCollectionChanging?

Please refer to the updated and optimized C# 7 version. I didn't want to remove the VB.NET version so I just posted it in a separate answer.

Go to updated version

Seems it's not supported, I implemented by myself, FYI, hope it to be helpful:

I updated the VB version and from now on it raises an event before changing the collection so you can regret (useful when using with DataGrid, ListView and many more, that you can show an "Are you sure" confirmation to the user), the updated VB version is in the bottom of this message.

Please accept my apology that the screen is too narrow to contain my code, I don't like it either.

VB.NET:

Imports System.Collections.Specialized

Namespace System.Collections.ObjectModel
    ''' <summary>
    ''' Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed.
    ''' </summary>
    ''' <typeparam name="T"></typeparam>
    Public Class ObservableRangeCollection(Of T) : Inherits System.Collections.ObjectModel.ObservableCollection(Of T)

        ''' <summary>
        ''' Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
        ''' </summary>
        Public Sub AddRange(ByVal collection As IEnumerable(Of T))
            For Each i In collection
                Items.Add(i)
            Next
            OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
        End Sub

        ''' <summary>
        ''' Removes the first occurence of each item in the specified collection from ObservableCollection(Of T).
        ''' </summary>
        Public Sub RemoveRange(ByVal collection As IEnumerable(Of T))
            For Each i In collection
                Items.Remove(i)
            Next

            OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
        End Sub

        ''' <summary>
        ''' Clears the current collection and replaces it with the specified item.
        ''' </summary>
        Public Sub Replace(ByVal item As T)
            ReplaceRange(New T() {item})
        End Sub
        ''' <summary>
        ''' Clears the current collection and replaces it with the specified collection.
        ''' </summary>
        Public Sub ReplaceRange(ByVal collection As IEnumerable(Of T))
            Dim old = Items.ToList
            Items.Clear()
            For Each i In collection
                Items.Add(i)
            Next
            OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
        End Sub

        ''' <summary>
        ''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class.
        ''' </summary>
        ''' <remarks></remarks>
        Public Sub New()
            MyBase.New()
        End Sub
        ''' <summary>
        ''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection.
        ''' </summary>
        ''' <param name="collection">collection: The collection from which the elements are copied.</param>
        ''' <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception>
        Public Sub New(ByVal collection As IEnumerable(Of T))
            MyBase.New(collection)
        End Sub
    End Class   

End Namespace

C#:

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Linq;

/// <summary> 
/// Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed. 
/// </summary> 
/// <typeparam name="T"></typeparam> 
public class ObservableRangeCollection<T> : ObservableCollection<T>
{
    /// <summary> 
    /// Adds the elements of the specified collection to the end of the ObservableCollection(Of T). 
    /// </summary> 
    public void AddRange(IEnumerable<T> collection)
    {
        if (collection == null) throw new ArgumentNullException("collection");

        foreach (var i in collection) Items.Add(i);
        OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
    }

    /// <summary> 
    /// Removes the first occurence of each item in the specified collection from ObservableCollection(Of T). 
    /// </summary> 
    public void RemoveRange(IEnumerable<T> collection)
    {
        if (collection == null) throw new ArgumentNullException("collection");

        foreach (var i in collection) Items.Remove(i);
        OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
    }

    /// <summary> 
    /// Clears the current collection and replaces it with the specified item. 
    /// </summary> 
    public void Replace(T item)
    {
        ReplaceRange(new T[] { item });
    }

    /// <summary> 
    /// Clears the current collection and replaces it with the specified collection. 
    /// </summary> 
    public void ReplaceRange(IEnumerable<T> collection)
    {
        if (collection == null) throw new ArgumentNullException("collection");

        Items.Clear();
        foreach (var i in collection) Items.Add(i);
        OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
    }

    /// <summary> 
    /// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class. 
    /// </summary> 
    public ObservableRangeCollection()
        : base() { }

    /// <summary> 
    /// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection. 
    /// </summary> 
    /// <param name="collection">collection: The collection from which the elements are copied.</param> 
    /// <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception> 
    public ObservableRangeCollection(IEnumerable<T> collection)
        : base(collection) { }
}

Update - Observable range collection with collection changing notification

Imports System.Collections.Specialized
Imports System.ComponentModel
Imports System.Collections.ObjectModel

Public Class ObservableRangeCollection(Of T) : Inherits ObservableCollection(Of T) : Implements INotifyCollectionChanging(Of T)
    ''' <summary>
    ''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class.
    ''' </summary>
    ''' <remarks></remarks>
    Public Sub New()
        MyBase.New()
    End Sub

    ''' <summary>
    ''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection.
    ''' </summary>
    ''' <param name="collection">collection: The collection from which the elements are copied.</param>
    ''' <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception>
    Public Sub New(ByVal collection As IEnumerable(Of T))
        MyBase.New(collection)
    End Sub

    ''' <summary>
    ''' Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
    ''' </summary>
    Public Sub AddRange(ByVal collection As IEnumerable(Of T))
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Add, collection)
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        Dim index = Items.Count - 1
        For Each i In collection
            Items.Add(i)
        Next

        OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, collection, index))
    End Sub


    ''' <summary>
    ''' Inserts the collection at specified index.
    ''' </summary>
    Public Sub InsertRange(ByVal index As Integer, ByVal Collection As IEnumerable(Of T))
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Add, Collection)
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        For Each i In Collection
            Items.Insert(index, i)
        Next

        OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
    End Sub


    ''' <summary>
    ''' Removes the first occurence of each item in the specified collection from ObservableCollection(Of T).
    ''' </summary>
    Public Sub RemoveRange(ByVal collection As IEnumerable(Of T))
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Remove, collection)
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        For Each i In collection
            Items.Remove(i)
        Next

        OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
    End Sub



    ''' <summary>
    ''' Clears the current collection and replaces it with the specified item.
    ''' </summary>
    Public Sub Replace(ByVal item As T)
        ReplaceRange(New T() {item})
    End Sub

    ''' <summary>
    ''' Clears the current collection and replaces it with the specified collection.
    ''' </summary>
    Public Sub ReplaceRange(ByVal collection As IEnumerable(Of T))
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Replace, Items)
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        Items.Clear()
        For Each i In collection
            Items.Add(i)
        Next
        OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
    End Sub

    Protected Overrides Sub ClearItems()
        Dim e As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Reset, Items)
        OnCollectionChanging(e)

        If e.Cancel Then Exit Sub

        MyBase.ClearItems()
    End Sub

    Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As T)
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Add, item)
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        MyBase.InsertItem(index, item)
    End Sub

    Protected Overrides Sub MoveItem(ByVal oldIndex As Integer, ByVal newIndex As Integer)
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)()
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        MyBase.MoveItem(oldIndex, newIndex)
    End Sub

    Protected Overrides Sub RemoveItem(ByVal index As Integer)
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Remove, Items(index))
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        MyBase.RemoveItem(index)
    End Sub

    Protected Overrides Sub SetItem(ByVal index As Integer, ByVal item As T)
        Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Replace, Items(index))
        OnCollectionChanging(ce)
        If ce.Cancel Then Exit Sub

        MyBase.SetItem(index, item)
    End Sub

    Protected Overrides Sub OnCollectionChanged(ByVal e As Specialized.NotifyCollectionChangedEventArgs)
        If e.NewItems IsNot Nothing Then
            For Each i As T In e.NewItems
                If TypeOf i Is INotifyPropertyChanged Then AddHandler DirectCast(i, INotifyPropertyChanged).PropertyChanged, AddressOf Item_PropertyChanged
            Next
        End If
        MyBase.OnCollectionChanged(e)
    End Sub

    Private Sub Item_PropertyChanged(ByVal sender As T, ByVal e As ComponentModel.PropertyChangedEventArgs)
        OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset, sender, IndexOf(sender)))
    End Sub

    Public Event CollectionChanging(ByVal sender As Object, ByVal e As NotifyCollectionChangingEventArgs(Of T)) Implements INotifyCollectionChanging(Of T).CollectionChanging
    Protected Overridable Sub OnCollectionChanging(ByVal e As NotifyCollectionChangingEventArgs(Of T))
        RaiseEvent CollectionChanging(Me, e)
    End Sub
End Class


Public Interface INotifyCollectionChanging(Of T)
    Event CollectionChanging(ByVal sender As Object, ByVal e As NotifyCollectionChangingEventArgs(Of T))
End Interface

Public Class NotifyCollectionChangingEventArgs(Of T) : Inherits CancelEventArgs

    Public Sub New()
        m_Action = NotifyCollectionChangedAction.Move
        m_Items = New T() {}
    End Sub

    Public Sub New(ByVal action As NotifyCollectionChangedAction, ByVal item As T)
        m_Action = action
        m_Items = New T() {item}
    End Sub

    Public Sub New(ByVal action As NotifyCollectionChangedAction, ByVal items As IEnumerable(Of T))
        m_Action = action
        m_Items = items
    End Sub

    Private m_Action As NotifyCollectionChangedAction
    Public ReadOnly Property Action() As NotifyCollectionChangedAction
        Get
            Return m_Action
        End Get
    End Property

    Private m_Items As IList
    Public ReadOnly Property Items() As IEnumerable(Of T)
        Get
            Return m_Items
        End Get
    End Property
End Class

Selecting with complex criteria from pandas.DataFrame

Another solution is to use the query method:

import pandas as pd

from random import randint
df = pd.DataFrame({'A': [randint(1, 9) for x in xrange(10)],
                   'B': [randint(1, 9) * 10 for x in xrange(10)],
                   'C': [randint(1, 9) * 100 for x in xrange(10)]})
print df

   A   B    C
0  7  20  300
1  7  80  700
2  4  90  100
3  4  30  900
4  7  80  200
5  7  60  800
6  3  80  900
7  9  40  100
8  6  40  100
9  3  10  600

print df.query('B > 50 and C != 900')

   A   B    C
1  7  80  700
2  4  90  100
4  7  80  200
5  7  60  800

Now if you want to change the returned values in column A you can save their index:

my_query_index = df.query('B > 50 & C != 900').index

....and use .iloc to change them i.e:

df.iloc[my_query_index, 0] = 5000

print df

      A   B    C
0     7  20  300
1  5000  80  700
2  5000  90  100
3     4  30  900
4  5000  80  200
5  5000  60  800
6     3  80  900
7     9  40  100
8     6  40  100
9     3  10  600

Difference between binary semaphore and mutex

The answer may depend on the target OS. For example, at least one RTOS implementation I'm familiar with will allow multiple sequential "get" operations against a single OS mutex, so long as they're all from within the same thread context. The multiple gets must be replaced by an equal number of puts before another thread will be allowed to get the mutex. This differs from binary semaphores, for which only a single get is allowed at a time, regardless of thread contexts.

The idea behind this type of mutex is that you protect an object by only allowing a single context to modify the data at a time. Even if the thread gets the mutex and then calls a function that further modifies the object (and gets/puts the protector mutex around its own operations), the operations should still be safe because they're all happening under a single thread.

{
    mutexGet();  // Other threads can no longer get the mutex.

    // Make changes to the protected object.
    // ...

    objectModify();  // Also gets/puts the mutex.  Only allowed from this thread context.

    // Make more changes to the protected object.
    // ...

    mutexPut();  // Finally allows other threads to get the mutex.
}

Of course, when using this feature, you must be certain that all accesses within a single thread really are safe!

I'm not sure how common this approach is, or whether it applies outside of the systems with which I'm familiar. For an example of this kind of mutex, see the ThreadX RTOS.

Adding a rule in iptables in debian to open a new port

About your command line:

root@debian:/# sudo iptables -A INPUT -p tcp --dport 3306 --jump ACCEPT
root@debian:/# iptables-save
  • You are already authenticated as root so sudo is redundant there.

  • You are missing the -j or --jump just before the ACCEPT parameter (just tought that was a typo and you are inserting it correctly).

About yout question:

If you are inserting the iptables rule correctly as you pointed it in the question, maybe the issue is related to the hypervisor (virtual machine provider) you are using.

If you provide the hypervisor name (VirtualBox, VMWare?) I can further guide you on this but here are some suggestions you can try first:

check your vmachine network settings and:

  • if it is set to NAT, then you won't be able to connect from your base machine to the vmachine.

  • if it is set to Hosted, you have to configure first its network settings, it is usually to provide them an IP in the range 192.168.56.0/24, since is the default the hypervisors use for this.

  • if it is set to Bridge, same as Hosted but you can configure it whenever IP range makes sense for you configuration.

Hope this helps.

Pass a string parameter in an onclick function

For passing multiple parameters you can cast the string by concatenating it with the ASCII value. Like, for single quotes we can use &#39;:

var str = "&#39;" + str + "&#39;";

The same parameter you can pass to the onclick() event. In most of the cases it works with every browser.

Lowercase and Uppercase with jQuery

Try this:

var jIsHasKids = $('#chkIsHasKids').attr('checked');
jIsHasKids = jIsHasKids.toString().toLowerCase();
//OR
jIsHasKids = jIsHasKids.val().toLowerCase();

Possible duplicate with: How do I use jQuery to ignore case when selecting

Oracle Convert Seconds to Hours:Minutes:Seconds

Unfortunately not... However, there's a simple trick if it's going to be less than 24 hours.

Oracle assumes that a number added to a date is in days. Convert the number of seconds into days. Add the current day, then use the to_date function to take only the parts your interested in. Assuming you have x seconds:

select to_char(sysdate + (x / ( 60 * 60 * 24 ) ), 'HH24:MI:SS')
  from dual

This won't work if there's more than 24 hours, though you can remove the current data again and get the difference in days, hours, minutes and seconds.

If you want something like: 51:10:05, i.e. 51 hours, 10 minutes and 5 seconds then you're going to have to use trunc.

Once again assuming that you have x seconds...

  • The number of hours is trunc(x / 60 / 60)
  • The number of minutes is trunc((x - ( trunc(x / 60 / 60) * 60 * 60 )) / 60)
  • The number of seconds is therefore the x - hours * 60 * 60 - minutes * 60

Leaving you with:

with hrs as (
  select x, trunc(x / 60 / 60) as h
    from dual
         )
 , mins as (
  select x, h, trunc((x - h * 60 * 60) / 60) as m
    from hrs
         )
select h, m, x - (h * 60 * 60) - (m * 60)
  from mins

I've set up a SQL Fiddle to demonstrate.

Get human readable version of file size?

One such library is hurry.filesize.

>>> from hurry.filesize import alternative
>>> size(1, system=alternative)
'1 byte'
>>> size(10, system=alternative)
'10 bytes'
>>> size(1024, system=alternative)
'1 KB'

How to convert CSV file to multiline JSON?

You can use Pandas DataFrame to achieve this, with the following Example:

import pandas as pd
csv_file = pd.DataFrame(pd.read_csv("path/to/file.csv", sep = ",", header = 0, index_col = False))
csv_file.to_json("/path/to/new/file.json", orient = "records", date_format = "epoch", double_precision = 10, force_ascii = True, date_unit = "ms", default_handler = None)

React passing parameter via onclick event using ES6 syntax

Use Arrow function like this:

<button onClick={()=>{this.handleRemove(id)}}></button>

Unresponsive KeyListener for JFrame

You must add your keyListener to every component that you need. Only the component with the focus will send these events. For instance, if you have only one TextBox in your JFrame, that TextBox has the focus. So you must add a KeyListener to this component as well.

The process is the same:

myComponent.addKeyListener(new KeyListener ...);

Note: Some components aren't focusable like JLabel.

For setting them to focusable you need to:

myComponent.setFocusable(true);

Different color for each bar in a bar chart; ChartJS

If you take a look at the library "ChartNew" which builds upon Chart.js you can do this by passing the values in as an array like so:

var data = {
    labels: ["Batman", "Iron Man", "Captain America", "Robin"],
    datasets: [
        {
            label: "My First dataset",
            fillColor: ["rgba(220,220,220,0.5)", "navy", "red", "orange"],
            strokeColor: "rgba(220,220,220,0.8)",
            highlightFill: "rgba(220,220,220,0.75)",
            highlightStroke: "rgba(220,220,220,1)",
            data: [2000, 1500, 1750, 50]
        }
    ]
};

Sublime text 3. How to edit multiple lines?

Thank you for all answers! I found it! It calls "Column selection (for Sublime)" and "Column Mode Editing (for Notepad++)" https://www.sublimetext.com/docs/3/column_selection.html

What exactly should be set in PYTHONPATH?

For most installations, you should not set these variables since they are not needed for Python to run. Python knows where to find its standard library.

The only reason to set PYTHONPATH is to maintain directories of custom Python libraries that you do not want to install in the global default location (i.e., the site-packages directory).

Make sure to read: http://docs.python.org/using/cmdline.html#environment-variables

write() versus writelines() and concatenated strings

Actually, I think the problem is that your variable "lines" is bad. You defined lines as a tuple, but I believe that write() requires a string. All you have to change is your commas into pluses (+).

nl = "\n"
lines = line1+nl+line2+nl+line3+nl
textdoc.writelines(lines)

should work.

What is the difference between H.264 video and MPEG-4 video?

H.264 is a new standard for video compression which has more advanced compression methods than the basic MPEG-4 compression. One of the advantages of H.264 is the high compression rate. It is about 1.5 to 2 times more efficient than MPEG-4 encoding. This high compression rate makes it possible to record more information on the same hard disk.
The image quality is also better and playback is more fluent than with basic MPEG-4 compression. The most interesting feature however is the lower bit-rate required for network transmission.
So the 3 main advantages of H.264 over MPEG-4 compression are:
- Small file size for longer recording time and better network transmission.
- Fluent and better video quality for real time playback
- More efficient mobile surveillance application

H264 is now enshrined in MPEG4 as part 10 also known as AVC

Refer to: http://www.velleman.eu/downloads/3/h264_vs_mpeg4_en.pdf

Hope this helps.

jQuery find element by data attribute value

you can also use andSelf() method to get wrapper DOM contain then find() can be work around as your idea

_x000D_
_x000D_
$(function() {_x000D_
  $('.slide-link').andSelf().find('[data-slide="0"]').addClass('active');_x000D_
})
_x000D_
.active {_x000D_
  background: green;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>_x000D_
<a class="slide-link" href="#" data-slide="0">1</a>_x000D_
<a class="slide-link" href="#" data-slide="1">2</a>_x000D_
<a class="slide-link" href="#" data-slide="2">3</a>
_x000D_
_x000D_
_x000D_

Spring data jpa- No bean named 'entityManagerFactory' is defined; Injection of autowired dependencies failed

Had this issue when migrated spring boot 1.5.2 to 2.0.4. Instead of creating bean I've used @EnableAutoConfiguration in the main class and it solved my problem.

Java Array, Finding Duplicates

To check for duplicates you need to compare distinct pairs.