Programs & Examples On #Motordriver

Decoding a Base64 string in Java

Modify the package you're using:

import org.apache.commons.codec.binary.Base64;

And then use it like this:

byte[] decoded = Base64.decodeBase64("YWJjZGVmZw==");
System.out.println(new String(decoded, "UTF-8") + "\n");

Google API for location, based on user IP address

Google already appends location data to all requests coming into GAE (see Request Header documentation for go, java, php and python). You should be interested X-AppEngine-Country, X-AppEngine-Region, X-AppEngine-City and X-AppEngine-CityLatLong headers.

An example looks like this:

X-AppEngine-Country:US
X-AppEngine-Region:ca
X-AppEngine-City:norwalk
X-AppEngine-CityLatLong:33.902237,-118.081733

What is the difference between Scala's case class and class?

Some of the key features of case classes are listed below

  1. case classes are immutable.
  2. You can instantiate case classes without new keyword.
  3. case classes can be compared by value

Sample scala code on scala fiddle, taken from the scala docs.

https://scalafiddle.io/sf/34XEQyE/0

Background service with location listener in android

Very easy no need create class extends LocationListener 1- Variable

private LocationManager mLocationManager;
private LocationListener mLocationListener;
private static double currentLat =0;
private static double currentLon =0;

2- onStartService()

@Override public void onStartService() {
    addListenerLocation();
}

3- Method addListenerLocation()

 private void addListenerLocation() {
    mLocationManager = (LocationManager)
            getSystemService(Context.LOCATION_SERVICE);
    mLocationListener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            currentLat = location.getLatitude();
            currentLon = location.getLongitude();

            Toast.makeText(getBaseContext(),currentLat+"-"+currentLon, Toast.LENGTH_SHORT).show();

        }

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

        @Override
        public void onProviderEnabled(String provider) {
            Location lastKnownLocation = mLocationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
            if(lastKnownLocation!=null){
                currentLat = lastKnownLocation.getLatitude();
                currentLon = lastKnownLocation.getLongitude();
            }

        }

        @Override
        public void onProviderDisabled(String provider) {
        }
    };
    mLocationManager.requestLocationUpdates(
            LocationManager.GPS_PROVIDER, 500, 10, mLocationListener);
}

4- onDestroy()

@Override
public void onDestroy() {
    super.onDestroy();
    mLocationManager.removeUpdates(mLocationListener);
}

Utils to read resource text file to String (Java)

For java 7:

new String(Files.readAllBytes(Paths.get(getClass().getResource("foo.txt").toURI())));

Python regular expressions return true/false

If you really need True or False, just use bool

>>> bool(re.search("hi", "abcdefghijkl"))
True
>>> bool(re.search("hi", "abcdefgijkl"))
False

As other answers have pointed out, if you are just using it as a condition for an if or while, you can use it directly without wrapping in bool()

How can I make this try_files directive work?

a very common try_files line which can be applied on your condition is

location / {
    try_files $uri $uri/ /test/index.html;
}

you probably understand the first part, location / matches all locations, unless it's matched by a more specific location, like location /test for example

The second part ( the try_files ) means when you receive a URI that's matched by this block try $uri first, for example http://example.com/images/image.jpg nginx will try to check if there's a file inside /images called image.jpg if found it will serve it first.

Second condition is $uri/ which means if you didn't find the first condition $uri try the URI as a directory, for example http://example.com/images/, ngixn will first check if a file called images exists then it wont find it, then goes to second check $uri/ and see if there's a directory called images exists then it will try serving it.

Side note: if you don't have autoindex on you'll probably get a 403 forbidden error, because directory listing is forbidden by default.

EDIT: I forgot to mention that if you have index defined, nginx will try to check if the index exists inside this folder before trying directory listing.

Third condition /test/index.html is considered a fall back option, (you need to use at least 2 options, one and a fall back), you can use as much as you can (never read of a constriction before), nginx will look for the file index.html inside the folder test and serve it if it exists.

If the third condition fails too, then nginx will serve the 404 error page.

Also there's something called named locations, like this

location @error {
}

You can call it with try_files like this

try_files $uri $uri/ @error;

TIP: If you only have 1 condition you want to serve, like for example inside folder images you only want to either serve the image or go to 404 error, you can write a line like this

location /images {
    try_files $uri =404;
}

which means either serve the file or serve a 404 error, you can't use only $uri by it self without =404 because you need to have a fallback option.
You can also choose which ever error code you want, like for example:

location /images {
    try_files $uri =403;
}

This will show a forbidden error if the image doesn't exist, or if you use 500 it will show server error, etc ..

Distribution certificate / private key not installed

In my case Xcode was not accessing certificates from the keychain, I followed these steps:

  1. delete certificates from the keychain.
  2. restart the mac.
  3. generate new certificates.
  4. install new certificates.
  5. clean build folder.
  6. build project.
  7. again clean build folder.
  8. archive now. It works That's it.

What's the difference between <b> and <strong>, <i> and <em>?

For text bold using <b> tag

For text important using <strong> tag

For text italic style using <i> tag

For emphasized text using <em> tag

How to get text in QlineEdit when QpushButton is pressed in a string?

My first suggestion is to use Designer to create your GUIs. Typing them out yourself sucks, takes more time, and you will definitely make more mistakes than Designer.

Here are some PyQt tutorials to help get you on the right track. The first one in the list is where you should start.

A good guide for figuring out what methods are available for specific classes is the PyQt4 Class Reference. In this case you would look up QLineEdit and see the there is a text method.

To answer your specific question:

To make your GUI elements available to the rest of the object, preface them with self.

import sys
from PyQt4.QtCore import SIGNAL
from PyQt4.QtGui import QDialog, QApplication, QPushButton, QLineEdit, QFormLayout

class Form(QDialog):
    def __init__(self, parent=None):
        super(Form, self).__init__(parent)

        self.le = QLineEdit()
        self.le.setObjectName("host")
        self.le.setText("Host")

        self.pb = QPushButton()
        self.pb.setObjectName("connect")
        self.pb.setText("Connect") 

        layout = QFormLayout()
        layout.addWidget(self.le)
        layout.addWidget(self.pb)

        self.setLayout(layout)
        self.connect(self.pb, SIGNAL("clicked()"),self.button_click)
        self.setWindowTitle("Learning")

    def button_click(self):
        # shost is a QString object
        shost = self.le.text()
        print shost


app = QApplication(sys.argv)
form = Form()
form.show()
app.exec_()

Python: Generate random number between x and y which is a multiple of 5

Create an integer random between e.g. 1-11 and multiply it by 5. Simple math.

import random
for x in range(20):
  print random.randint(1,11)*5,
print

produces e.g.

5 40 50 55 5 15 40 45 15 20 25 40 15 50 25 40 20 15 50 10

How can I autoformat/indent C code in vim?

I wanted to add, that in order to prevent it from being messed up in the first place you can type :set paste before pasting. After pasting, you can type :set nopaste for things like js-beautify and indenting to work again.

CSS Background image not loading

The path to the image should be relative, that means if css file is in css folder than you should start path with ../ such as

_x000D_
_x000D_
body{_x000D_
   background-image: url(../images/logo.jpg);_x000D_
}
_x000D_
_x000D_
_x000D_

this is because you have to get back to home dir by ../ path and then /images/logo.jpg path to the image file. If you are including css file in html itself

_x000D_
_x000D_
body{_x000D_
   background-image: url(images/logo.jpg);_x000D_
}
_x000D_
_x000D_
_x000D_ this code will work just fine.

Add column to SQL Server

Adding a column using SSMS or ALTER TABLE .. ADD will not drop any existing data.

Can we use join for two different database tables?

You could use Synonyms part in the database.

enter image description here

Then in view wizard from Synonyms tab find your saved synonyms and add to view and set inner join simply. enter image description here

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

If it instead returned Option[QueueObject] you could use a construct like getObject.foreach { QueueManager.add }. You can wrap it right inline with Option(getObject).foreach ... because Option[QueueObject](null) is None.

Spring Boot REST service exception handling

What about this code ? I use a fallback request mapping to catch 404 errors.

@Controller
@ControllerAdvice
public class ExceptionHandlerController {

    @ExceptionHandler(Exception.class)
    public ModelAndView exceptionHandler(HttpServletRequest request, HttpServletResponse response, Exception ex) {
        //If exception has a ResponseStatus annotation then use its response code
        ResponseStatus responseStatusAnnotation = AnnotationUtils.findAnnotation(ex.getClass(), ResponseStatus.class);

        return buildModelAndViewErrorPage(request, response, ex, responseStatusAnnotation != null ? responseStatusAnnotation.value() : HttpStatus.INTERNAL_SERVER_ERROR);
    }

    @RequestMapping("*")
    public ModelAndView fallbackHandler(HttpServletRequest request, HttpServletResponse response) throws Exception {
        return buildModelAndViewErrorPage(request, response, null, HttpStatus.NOT_FOUND);
    }

    private ModelAndView buildModelAndViewErrorPage(HttpServletRequest request, HttpServletResponse response, Exception ex, HttpStatus httpStatus) {
        response.setStatus(httpStatus.value());

        ModelAndView mav = new ModelAndView("error.html");
        if (ex != null) {
            mav.addObject("title", ex);
        }
        mav.addObject("content", request.getRequestURL());
        return mav;
    }

}

Importing a long list of constants to a Python file

And ofcourse you can do:

# a.py
MY_CONSTANT = ...

# b.py
from a import *
print MY_CONSTANT

What does #defining WIN32_LEAN_AND_MEAN exclude exactly?

Directly from the Windows.h header file:

#ifndef WIN32_LEAN_AND_MEAN
    #include <cderr.h>
    #include <dde.h>
    #include <ddeml.h>
    #include <dlgs.h>
    #ifndef _MAC
        #include <lzexpand.h>
        #include <mmsystem.h>
        #include <nb30.h>
        #include <rpc.h>
    #endif
    #include <shellapi.h>
    #ifndef _MAC
        #include <winperf.h>
        #include <winsock.h>
    #endif
    #ifndef NOCRYPT
        #include <wincrypt.h>
        #include <winefs.h>
        #include <winscard.h>
    #endif

    #ifndef NOGDI
        #ifndef _MAC
            #include <winspool.h>
            #ifdef INC_OLE1
                #include <ole.h>
            #else
                #include <ole2.h>
            #endif /* !INC_OLE1 */
        #endif /* !MAC */
        #include <commdlg.h>
    #endif /* !NOGDI */
#endif /* WIN32_LEAN_AND_MEAN */

if you want to know what each of the headers actually do, typeing the header names into the search in the MSDN library will usually produce a list of the functions in that header file.

Also, from Microsoft's support page:

To speed the build process, Visual C++ and the Windows Headers provide the following new defines:

VC_EXTRALEAN
WIN32_LEAN_AND_MEAN

You can use them to reduce the size of the Win32 header files.

Finally, if you choose to use either of these preprocessor defines, and something you need is missing, you can just include that specific header file yourself. Typing the name of the function you're after into MSDN will usually produce an entry which will tell you which header to include if you want to use it, at the bottom of the page.

Print a file's last modified date in Bash

Isn't the 'date' command much simpler? No need for awk, stat, etc.

date -r <filename>

Also, consider looking at the man page for date formatting; for example with common date and time format:

date -r <filename> "+%m-%d-%Y %H:%M:%S"

HTTP POST using JSON in Java

Java 8 with apache httpClient 4

CloseableHttpClient client = HttpClientBuilder.create().build();
HttpPost httpPost = new HttpPost("www.site.com");


String json = "details={\"name\":\"myname\",\"age\":\"20\"} ";

        try {
            StringEntity entity = new StringEntity(json);
            httpPost.setEntity(entity);

            // set your POST request headers to accept json contents
            httpPost.setHeader("Accept", "application/json");
            httpPost.setHeader("Content-type", "application/json");

            try {
                // your closeablehttp response
                CloseableHttpResponse response = client.execute(httpPost);

                // print your status code from the response
                System.out.println(response.getStatusLine().getStatusCode());

                // take the response body as a json formatted string 
                String responseJSON = EntityUtils.toString(response.getEntity());

                // convert/parse the json formatted string to a json object
                JSONObject jobj = new JSONObject(responseJSON);

                //print your response body that formatted into json
                System.out.println(jobj);

            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {

                e.printStackTrace();
            }

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

Pandas KeyError: value not in index

please try this to clean and format your column names:

df.columns = (df.columns.str.strip().str.upper()
              .str.replace(' ', '_')
              .str.replace('(', '')
              .str.replace(')', ''))

how to concat two columns into one with the existing column name in mysql?

As aziz-shaikh has pointed out, there is no way to suppress an individual column from the * directive, however you might be able to use the following hack:

SELECT CONCAT(c.FIRSTNAME, ',', c.LASTNAME) AS FIRSTNAME,
       c.*
FROM   `customer` c;

Doing this will cause the second occurrence of the FIRSTNAME column to adopt the alias FIRSTNAME_1 so you should be able to safely address your customised FIRSTNAME column. You need to alias the table because * in any position other than at the start will fail if not aliased.

Hope that helps!

Execute a file with arguments in Python shell

import sys
import subprocess

subprocess.call([sys.executable, 'abc.py', 'argument1', 'argument2'])

How to add buttons at top of map fragment API v2 layout

You can use the below code to change the button to Left side.

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.zakasoft.mymap.MapsActivity" >

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="left|top"
        android:text="Send"
        android:padding="10dp"
        android:layout_marginTop="20dp"
        android:paddingRight="10dp"/>

</fragment>

In AVD emulator how to see sdcard folder? and Install apk to AVD?

Adding to the usefile DDMS/File Explorer solution, for those that don't know, if you want to read a file you need to select the "Pull File from Device" button on the file viewer toolbar. Unfortunately you can't just drag out, or double click to read.

Installing Python library from WHL file

First open a console then cd to where you've downloaded your file like some-package.whl and use

pip install some-package.whl

Note: if pip.exe is not recognized, you may find it in the "Scripts" directory from where python has been installed. I have multiple Python installations, and needed to use the pip associated with Python 3 to install a version 3 wheel.

If pip is not installed, and you are using Windows: How to install pip on Windows?

ERROR: Error 1005: Can't create table (errno: 121)

mysql> SHOW ENGINE INNODB STATUS;

But in my case only this way could help:
1. Make backup of current DB
2. Drop DB (not all tables, but DB)
3. Create DB (check that you still have previleges)
4. Restore DB from backup

Differences between "java -cp" and "java -jar"?

There won't be any difference in terms of performance. Using java - cp we can specify the required classes and jar's in the classpath for running a java class file.

If it is a executable jar file . When java -jar command is used, jvm finds the class that it needs to run from /META-INF/MANIFEST.MF file inside the jar file.

Android studio, gradle and NDK

NDK Builds and gradle (basic)

Generally building with the NDK is as simple as correctly specifying an ndkBuild path to Android.mk or cmake path to CMakeLists.txt. I recommend CMake over the older Android.mk because Android Studio's C/C++ support is based upon CLion and it uses CMake as its project format. This in my experience has tended to make the IDE more responsive on larger projects. Everything compiled in your project will be built and copied into the APK automatically.

apply plugin: 'com.android.library'

android {
    compileSdkVersion 19
    buildToolsVersion "25.0.2"

    defaultConfig {
        minSdkVersion 19
        targetSdkVersion 19

        ndk {
            abiFilters 'armeabi', 'armeabi-v7a', 'x86'
            // 64-bit support requires an Android API level higher than 19; Namely 21 and higher
            //abiFilters 'armeabi', 'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64'
        }

        externalNativeBuild {
            cmake {
                arguments '-DANDROID_TOOLCHAIN=clang',
                        '-DANDROID_PLATFORM=android-19',
                        '-DANDROID_STL=gnustl_static',
                        '-DANDROID_ARM_NEON=TRUE'

            }
        }
    }

    externalNativeBuild {
        cmake {
            path 'src/main/jni/CMakeLists.txt'
        }
    }
}

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

Adding prebuilt libraries to the project (advanced)

Static libraries (.a) in your NDK build will automatically be included, but prebuilt dynamic libraries (.so) will need to be placed in jniLibs. This can be configured using sourceSets, but you should adopt the standard. You DO NOT NEED any additional commands in build.gradle when including prebuilt libraries.

The layout of jniLibs

You can find more information about the structure in the Android Gradle Plugin User Guide.

|--app:
|--|--build.gradle
|--|--src:
|--|--|--main
|--|--|--|--java
|--|--|--|--jni
|--|--|--|--|--CMakeLists.txt
|--|--|--|--jniLibs
|--|--|--|--|--armeabi
|--|--|--|--|--|--.so Files
|--|--|--|--|--armeabi-v7a
|--|--|--|--|--|--.so Files
|--|--|--|--|--x86
|--|--|--|--|--|--.so Files

You can then validate the resulting APK contains your .so files, typically under build/outputs/apk/, using unzip -l myApp.apk to list the contents.

Building shared libraries

If you're building a shared library in the NDK you do not need to do anything further. It will be correctly bundled in the APK.

Calling startActivity() from outside of an Activity context

I think maybe you are implementing the OnClickListener in the wrong place - usually you should definitely implement an OnItemClickListener in your Activity and set it on the ListView instead, or you will get problems with your events...

OSError - Errno 13 Permission denied

You need to change the directory permission so that web server process can change the directory.

  • To change ownership of the directory, use chown:

    chown -R user-id:group-id /path/to/the/directory
    
  • To see which user own the web server process (change httpd accordingly):

    ps aux | grep httpd | grep -v grep
    

    OR

    ps -efl | grep httpd | grep -v grep
    

how to run command "mysqladmin flush-hosts" on Amazon RDS database Server instance?

Since the hosts is blocked. try connect it from other host and execute the mysqladmin flush-hosts command.

mysqladmin -h <RDS ENDPOINT URL> -P <PORT> -u <USER> -p flush-hosts

How can I get the last character in a string?

 var myString = "Test3";
 alert(myString[myString.length-1])

here is a simple fiddle

http://jsfiddle.net/MZEqD/

batch file Copy files with certain extensions from multiple directories into one directory

Just use the XCOPY command with recursive option

xcopy c:\*.doc k:\mybackup /sy

/s will make it "recursive"

Bash scripting missing ']'

add a space before the close bracket

how to compare the Java Byte[] array?

Use Arrays.equals() if you want to compare the actual content of arrays that contain primitive types values (like byte).

System.out.println(Arrays.equals(aa, bb));

Use Arrays.deepEquals for comparison of arrays that contain objects.

jQuery/JavaScript to replace broken images

This is JavaScript, should be cross browser compatible, and delivers without the ugly markup onerror="":

var sPathToDefaultImg = 'http://cdn.sstatic.net/stackexchange/img/logos/so/so-icon.png',
    validateImage = function( domImg ) {
        oImg = new Image();
        oImg.onerror = function() {
            domImg.src = sPathToDefaultImg;
        };
        oImg.src = domImg.src;
    },
    aImg = document.getElementsByTagName( 'IMG' ),
    i = aImg.length;

while ( i-- ) {
    validateImage( aImg[i] );
}

CODEPEN:

How to lose margin/padding in UITextView?

Here is an updated version of Fattie's very helpful answer. It adds 2 important lines that helped me get the layout working on iOS 10 and 11 (and probably on lower ones, too):

@IBDesignable class UITextViewFixed: UITextView {
    override func layoutSubviews() {
        super.layoutSubviews()
        setup()
    }
    func setup() {
        translatesAutoresizingMaskIntoConstraints = true
        textContainerInset = UIEdgeInsets.zero
        textContainer.lineFragmentPadding = 0
        translatesAutoresizingMaskIntoConstraints = false
    }
}

The important lines are the two translatesAutoresizingMaskIntoConstraints = <true/false> statements!

This surprisingly removes all margins in all my circumstances!

While the textView is not the first responder it could happen that there is some strange bottom margin that could not be solved using the sizeThatFits method that is mentioned in the accepted answer.

When tapping into the textView suddenly the strange bottom margin disappeared and everything looked like it should, but only as soon as the textView has got firstResponder.

So I read here on SO that enabling and disabling translatesAutoresizingMaskIntoConstraints does help when setting the frame/bounds manually in between the calls.

Fortunately this not only works with frame setting but with the 2 lines of setup() sandwiched between the two translatesAutoresizingMaskIntoConstraints calls!

This for example is very helpful when calculating the frame of a view using systemLayoutSizeFitting on a UIView. Gives back the correct size (which previously it didn't)!

As in the original answer mentioned:
Don't forget to turn off scrollEnabled in the Inspector!
That solution does work properly in storyboard, as well as at runtime.

That's it, now you're really done!

Calculate distance between 2 GPS coordinates

I needed to calculate a lot of distances between the points for my project, so I went ahead and tried to optimize the code, I have found here. On average in different browsers my new implementation runs 2 times faster than the most upvoted answer.

function distance(lat1, lon1, lat2, lon2) {
  var p = 0.017453292519943295;    // Math.PI / 180
  var c = Math.cos;
  var a = 0.5 - c((lat2 - lat1) * p)/2 + 
          c(lat1 * p) * c(lat2 * p) * 
          (1 - c((lon2 - lon1) * p))/2;

  return 12742 * Math.asin(Math.sqrt(a)); // 2 * R; R = 6371 km
}

You can play with my jsPerf and see the results here.

Recently I needed to do the same in python, so here is a python implementation:

from math import cos, asin, sqrt
def distance(lat1, lon1, lat2, lon2):
    p = 0.017453292519943295
    a = 0.5 - cos((lat2 - lat1) * p)/2 + cos(lat1 * p) * cos(lat2 * p) * (1 - cos((lon2 - lon1) * p)) / 2
    return 12742 * asin(sqrt(a))

And for the sake of completeness: Haversine on wiki.

change cursor from block or rectangle to line?

If you happen to be using a mac keyboard on linux (ubuntu), Insert is actually fn + return. You can also click on the zero of the number pad to switch between the cursor types.

Took me a while to figure that out. :-P

How can I check if a key exists in a dictionary?

If you want to retrieve the key's value if it exists, you can also use

try:
    value = a[key]
except KeyError:
    # Key is not present
    pass

If you want to retrieve a default value when the key does not exist, use value = a.get(key, default_value). If you want to set the default value at the same time in case the key does not exist, use value = a.setdefault(key, default_value).

Allow anonymous authentication for a single folder in web.config?

Use <location> configuration tag, and <allow users="?"/> to allow anonymous only or <allow users="*"/> for all:

<configuration>
   <location path="Path/To/Public/Folder">
      <system.web>
         <authorization>
            <allow users="?"/>
         </authorization>
      </system.web>
   </location>
</configuration>

Change primary key column in SQL Server

Assuming that your current primary key constraint is called pk_history, you can replace the following lines:

ALTER TABLE history ADD PRIMARY KEY (id)

ALTER TABLE history
DROP CONSTRAINT userId
DROP CONSTRAINT name

with these:

ALTER TABLE history DROP CONSTRAINT pk_history

ALTER TABLE history ADD CONSTRAINT pk_history PRIMARY KEY (id)

If you don't know what the name of the PK is, you can find it with the following query:

SELECT * 
  FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
 WHERE TABLE_NAME = 'history'

html vertical align the text inside input type button

I've given up trying to align my text on buttons! Now, if I need it, I'm using <a> tags, like so:

<a href="javascript:void();" style="display:block;font-size:1em;padding:5px;cursor:default;" onclick="document.getElementById('form').submit();">Submit</a>

So, if the document's font size is 12px, my "button" will have 22px height. And the text will be vertically align. That in theory, because, in some casses, an unequal padding of "6px 5px 4px 5px" will do the job done.

Although, is a hack, this technique is pretty good for solving compatibility issues in older browsers too, like IE6!

Checking if a date is valid in javascript

Try this:

var date = new Date();
console.log(date instanceof Date && !isNaN(date.valueOf()));

This should return true.

UPDATED: Added isNaN check to handle the case commented by Julian H. Lam

Who sets response content-type in Spring MVC (@ResponseBody)

Thanks digz6666, your solution works for me with a slight changes because I'm using json:

responseHeaders.add("Content-Type", "application/json; charset=utf-8");

The answer given by axtavt (whch you've recommended) wont work for me. Even if I've added the correct media type:

if (conv instanceof StringHttpMessageConverter) {                   
                    ((StringHttpMessageConverter) conv).setSupportedMediaTypes(
                        Arrays.asList(
                                new MediaType("text", "html", Charset.forName("UTF-8")),
                                new MediaType("application", "json", Charset.forName("UTF-8")) ));
                }

The tilde operator in Python

Besides being a bitwise complement operator, ~ can also help revert a boolean value, though it is not the conventional bool type here, rather you should use numpy.bool_.


This is explained in,

import numpy as np
assert ~np.True_ == np.False_

Reversing logical value can be useful sometimes, e.g., below ~ operator is used to cleanse your dataset and return you a column without NaN.

from numpy import NaN
import pandas as pd

matrix = pd.DataFrame([1,2,3,4,NaN], columns=['Number'], dtype='float64')
# Remove NaN in column 'Number'
matrix['Number'][~matrix['Number'].isnull()]

Select All checkboxes using jQuery

$(document).ready(function() {
    $('#ckbCheckAll').click(function() {
        $('.checkBoxClass').each(function() {
            $(this).attr('checked',!$(this).attr('checked'));
        });
    });
});

OR

$(function () {
    $('#ckbCheckAll').toggle(
        function() {
            $('.checkBoxClass').prop('checked', true);
        },
        function() {
            $('.checkBoxClass').prop('checked', false);
        }
    );
});

Change color and appearance of drop down arrow

It can be done by:

select{
  background: url(data:image/svg+xml;base64,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) no-repeat 100% 50%;
}

_x000D_
_x000D_
select{_x000D_
  background: url(data:image/svg+xml;base64,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) no-repeat 100% 50%;_x000D_
  _x000D_
  _x000D_
    -moz-appearance: none;_x000D_
    -webkit-appearance: none;_x000D_
    -webkit-border-radius: 0px;_x000D_
    appearance: none;_x000D_
    outline-width: 0;_x000D_
    _x000D_
    padding: 10px 10px 10px 5px;_x000D_
    display: block;_x000D_
    width: 10em;_x000D_
    border: none;_x000D_
    font-size: 1rem;_x000D_
    _x000D_
    border-bottom: 1px solid #757575;_x000D_
  }
_x000D_
<div class="styleSelect">_x000D_
  <select class="units">_x000D_
    <option value="Metres">Metres</option>_x000D_
    <option value="Feet">Feet</option>_x000D_
    <option value="Fathoms">Fathoms</option>_x000D_
  </select>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Setting background color for a JFrame

To set the background color for JFrame:

getContentPane().setBackground(Color.YELLOW);  //Whatever color

How to make a edittext box in a dialog

Use Activtiy Context

Replace this

  final EditText input = new EditText(this);

By

  final EditText input = new EditText(MainActivity.this);  
  LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                        LinearLayout.LayoutParams.MATCH_PARENT,
                        LinearLayout.LayoutParams.MATCH_PARENT);
  input.setLayoutParams(lp);
  alertDialog.setView(input); // uncomment this line

Function not defined javascript

important: in this kind of error you should look for simple mistakes in most cases

besides syntax error, I should say once I had same problem and it was because of bad name I have chosen for function. I have never searched for the reason but I remember that I copied another function and change it to use. I add "1" after the name to changed the function name and I got this error.

Regex select all text between tags

use the below pattern to get content between element. Replace [tag] with the actual element you wish to extract the content from.

<[tag]>(.+?)</[tag]>

Sometime tags will have attributes, like anchor tag having href, then use the below pattern.

 <[tag][^>]*>(.+?)</[tag]>

Copy array items into another array

Found an elegant way from MDN

var vegetables = ['parsnip', 'potato'];
var moreVegs = ['celery', 'beetroot'];

// Merge the second array into the first one
// Equivalent to vegetables.push('celery', 'beetroot');
Array.prototype.push.apply(vegetables, moreVegs);

console.log(vegetables); // ['parsnip', 'potato', 'celery', 'beetroot']

Or you can use the spread operator feature of ES6:

let fruits = [ 'apple', 'banana'];
const moreFruits = [ 'orange', 'plum' ];

fruits.push(...moreFruits); // ["apple", "banana", "orange", "plum"]

How to use forEach in vueJs?

In VueJS you can use forEach like below.

let list=[];
$.each(response.data.message, function(key, value) {
     list.push(key);
   });

So, now you can have all arrays into list . use for loop to get values or keys

Confirm button before running deleting routine from website

Try this one :

 <script type="text/javascript">
      var baseUrl='http://example.com';
      function ConfirmDelete()
      {
            if (confirm("Delete Account?"))
                 location.href=baseUrl+'/deleteRecord.php';
      }
  </script>


  echo '<a type="button" onclick="ConfirmDelete()">DELETE ACCOUNT</a>';

Get user's current location

as PHP relies on server, the real-time location cant be provided only static location can be provided it is better to avoid to rely on the JS for location rather than using php. But there is a need to post the js data to php so that it can be easily be accesible to program on server

how to create a login page when username and password is equal in html

Doing password checks on client side is unsafe especially when the password is hard coded.

The safest way is password checking on server side, but even then the password should not be transmitted plain text.

Checking the password client side is possible in a "secure way":

  • The password needs to be hashed
  • The hashed password is used as part of a new url

Say "abc" is your password so your md5 would be "900150983cd24fb0d6963f7d28e17f72" (consider salting!). Now build a url containing the hash (like http://yourdomain.com/90015...f72.html).

selecting an entire row based on a variable excel vba

One needs to make sure the space between the variables and '&' sign. Check the image. (Red one showing invalid commands)

Error

The correct solution is

Dim copyToRow: copyToRow = 5      
Rows(copyToRow & ":" & copyToRow).Select

Correct way to detach from a container without stopping it

In Docker container atleast one process must be run, then only the container will be running the docker image(ubuntu,httd..etc, whatever it is) at background without exiting

For example in ubuntu docker image ,

To create a new container with detach mode (running background atleast on process),

docker run -d -i -t f63181f19b2f /bin/bash

it will create a new contain for this image(ubuntu) id f63181f19b2f . The container will run in the detached mode (running in background) at that time a small process tty bash shell will be running at background. so, container will keep on running untill the bash shell process will killed.

To attach to the running background container,use

docker attach  b1a0873a8647

if you want to detach from container without exiting(without killing the bash shell), By default , you can use ctrl-p,q. it will come out of container without exiting from the container(running background. that means without killing the bash shell).

You can pass the custom command during attach time to container,

docker attach --detach-keys="ctrl-s" b1a0873a8647

this time ctrl-p,q escape sequence won't work. instead, ctrl-s will work for exiting from container. you can pass any key eg, (ctrl-*)

What is the best (idiomatic) way to check the type of a Python variable?

type(dict()) says "make a new dict, and then find out what its type is". It's quicker to say just dict. But if you want to just check type, a more idiomatic way is isinstance(x, dict).

Note, that isinstance also includes subclasses (thanks Dustin):

class D(dict):
    pass

d = D()
print("type(d) is dict", type(d) is dict)  # -> False
print("isinstance (d, dict)", isinstance(d, dict))  # -> True

Importing images from a directory (Python) to list or dictionary

from PIL import Image
import os, os.path

imgs = []
path = "/home/tony/pictures"
valid_images = [".jpg",".gif",".png",".tga"]
for f in os.listdir(path):
    ext = os.path.splitext(f)[1]
    if ext.lower() not in valid_images:
        continue
    imgs.append(Image.open(os.path.join(path,f)))
   

iPad WebApp Full Screen in Safari

It only opens the first (bookmarked) page full screen. Any next page will be opened WITH the address bar visible again. Whatever meta tag you put into your page header...

What can MATLAB do that R cannot do?

We can't because it's expected/required by our customers.

Delete all objects in a list

Here's how you delete every item from a list.

del c[:]

Here's how you delete the first two items from a list.

del c[:2]

Here's how you delete a single item from a list (a in your case), assuming c is a list.

del c[0]

Animate element to auto height with jQuery

you can always do this:

jQuery.fn.animateAuto = function(prop, speed, callback){
var elem, height, width;
return this.each(function(i, el){
    el = jQuery(el), elem = el.clone().css({"height":"auto","width":"auto"}).appendTo("body");
    height = elem.css("height"),
    width = elem.css("width"),
    elem.remove();

    if(prop === "height")
        el.animate({"height":height}, speed, callback);
    else if(prop === "width")
        el.animate({"width":width}, speed, callback);  
    else if(prop === "both")
        el.animate({"width":width,"height":height}, speed, callback);
});  
}

here is a fiddle: http://jsfiddle.net/Zuriel/faE9w/2/

Hashset vs Treeset

HashSet is O(1) to access elements, so it certainly does matter. But maintaining order of the objects in the set isn't possible.

TreeSet is useful if maintaining an order(In terms of values and not the insertion order) matters to you. But, as you've noted, you're trading order for slower time to access an element: O(log n) for basic operations.

From the javadocs for TreeSet:

This implementation provides guaranteed log(n) time cost for the basic operations (add, remove and contains).

How can I create database tables from XSD files?

I use XSLT to do that. Write up your XSD then pass your data models through a hand written XSLT that outputs SQL commands. Writing an XSLT is way faster and reusable than a custom program /script you may write.

At least thats how I do it at work, and thanks to that I got time to hang out on SO :)

How to set up datasource with Spring for HikariCP?

my test java config (for MySql)

@Bean(destroyMethod = "close")
public DataSource dataSource(){
    HikariConfig hikariConfig = new HikariConfig();
    hikariConfig.setDriverClassName("com.mysql.jdbc.Driver");
    hikariConfig.setJdbcUrl("jdbc:mysql://localhost:3306/spring-test"); 
    hikariConfig.setUsername("root");
    hikariConfig.setPassword("admin");

    hikariConfig.setMaximumPoolSize(5);
    hikariConfig.setConnectionTestQuery("SELECT 1");
    hikariConfig.setPoolName("springHikariCP");

    hikariConfig.addDataSourceProperty("dataSource.cachePrepStmts", "true");
    hikariConfig.addDataSourceProperty("dataSource.prepStmtCacheSize", "250");
    hikariConfig.addDataSourceProperty("dataSource.prepStmtCacheSqlLimit", "2048");
    hikariConfig.addDataSourceProperty("dataSource.useServerPrepStmts", "true");

    HikariDataSource dataSource = new HikariDataSource(hikariConfig);

    return dataSource;
}

Why does DEBUG=False setting make my django Static Files Access fail?

If you still need to server static locally (e.g. for testing without debug) you can run devserver in insecure mode:

manage.py runserver --insecure

Creating a UITableView Programmatically

Creating a tableview using tableViewController .

import UIKit

class TableViewController: UITableViewController
{
    let tableViewModel = TableViewModel()
    var product: [String] = []
    var price: [String] = []
    override func viewDidLoad()
    {
        super.viewDidLoad()
        self.tableView.contentInset = UIEdgeInsetsMake( 20, 20 , 0, 0)
        let priceProductDetails = tableViewModel.dataProvider()

        for (key, value) in priceProductDetails
        {
            product.append(key)
            price.append(value)
        }
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
    {
        return product.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
    {
        let cell = UITableViewCell(style: .Value1, reuseIdentifier: "UITableViewCell")
        cell.textLabel?.text = product[indexPath.row]
        cell.detailTextLabel?.text = price[indexPath.row]
        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
    {
        print("You tapped cell number \(indexPath.row).")
    }
}

Passing an array of parameters to a stored procedure

You could try this:



DECLARE @List VARCHAR(MAX)

SELECT @List = '1,2,3,4,5,6,7,8'

EXEC(
'DELETE
FROM TABLE
WHERE ID NOT IN (' + @List + ')'
)

Converting java.util.Properties to HashMap<String,String>

i use this:

for (Map.Entry<Object, Object> entry:properties.entrySet()) {
    map.put((String) entry.getKey(), (String) entry.getValue());
}

How to grep and replace

Usually not with grep, but rather with sed -i 's/string_to_find/another_string/g' or perl -i.bak -pe 's/string_to_find/another_string/g'.

How to import a module given its name as string?

The below piece worked for me:

>>>import imp; 
>>>fp, pathname, description = imp.find_module("/home/test_module"); 
>>>test_module = imp.load_module("test_module", fp, pathname, description);
>>>print test_module.print_hello();

if you want to import in shell-script:

python -c '<above entire code in one line>'

Match linebreaks - \n or \r\n?

Gonna answer in opposite direction.

2) For a full explanation about \r and \n I have to refer to this question, which is far more complete than I will post here: Difference between \n and \r?

Long story short, Linux uses \n for a new-line, Windows \r\n and old Macs \r. So there are multiple ways to write a newline. Your second tool (RegExr) does for example match on the single \r.

1) [\r\n]+ as Ilya suggested will work, but will also match multiple consecutive new-lines. (\r\n|\r|\n) is more correct.

Comparing Class Types in Java

If you had two Strings and compared them using == by calling the getClass() method on them, it would return true. What you get is a reference on the same object.

This is because they are both references on the same class object. This is true for all classes in a java application. Java only loads the class once, so you have only one instance of a given class at a given time.

String hello  = "Hello";
String world = "world";

if (hello.getClass() == world.getClass()) {
    System.out.println("true");
} // prints true

ConcurrentHashMap vs Synchronized HashMap

We can achieve thread safety by using both ConcurrentHashMap and synchronisedHashmap. But there is a lot of difference if you look at their architecture.

  1. synchronisedHashmap

It will maintain the lock at the object level. So if you want to perform any operation like put/get then you have to acquire the lock first. At the same time, other threads are not allowed to perform any operation. So at a time, only one thread can operate on this. So the waiting time will increase here. We can say that performance is relatively low when you are comparing with ConcurrentHashMap.

  1. ConcurrentHashMap

It will maintain the lock at the segment level. It has 16 segments and maintains the concurrency level as 16 by default. So at a time, 16 threads can be able to operate on ConcurrentHashMap. Moreover, read operation doesn't require a lock. So any number of threads can perform a get operation on it.

If thread1 wants to perform put operation in segment 2 and thread2 wants to perform put operation on segment 4 then it is allowed here. Means, 16 threads can perform update(put/delete) operation on ConcurrentHashMap at a time.

So that the waiting time will be less here. Hence the performance is relatively better than synchronisedHashmap.

__init__ and arguments in Python

In Python:

  • Instance methods: require the self argument.
  • Class methods: take the class as a first argument.
  • Static methods: do not require either the instance (self) or the class (cls) argument.

__init__ is a special function and without overriding __new__ it will always be given the instance of the class as its first argument.

An example using the builtin classmethod and staticmethod decorators:

import sys

class Num:
    max = sys.maxint

    def __init__(self,num):
        self.n = num

    def getn(self):
        return self.n

    @staticmethod
    def getone():
        return 1

    @classmethod
    def getmax(cls):
        return cls.max

myObj = Num(3)
# with the appropriate decorator these should work fine
myObj.getone()
myObj.getmax()
myObj.getn()

That said, I would try to use @classmethod/@staticmethod sparingly. If you find yourself creating objects that consist of nothing but staticmethods the more pythonic thing to do would be to create a new module of related functions.

Create HTTP post request and receive response using C# console application

For this you can simply use the "HttpWebRequest" and "HttpWebResponse" classes in .net.

Below is a sample console app I wrote to demonstrate how easy this is.

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.IO;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            string url = "www.somewhere.com";       
            string fileName = @"C:\output.file";

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Timeout = 5000;

            try
            {
                using (WebResponse response = (HttpWebResponse)request.GetResponse())
                {
                    using (FileStream stream = new FileStream(fileName, FileMode.Create, FileAccess.Write))
                    {
                        byte[] bytes = ReadFully(response.GetResponseStream());

                        stream.Write(bytes, 0, bytes.Length);
                    }
                }
            }
            catch (WebException)
            {
                Console.WriteLine("Error Occured");
            }
        }

        public static byte[] ReadFully(Stream input)
        {
            byte[] buffer = new byte[16 * 1024];
            using (MemoryStream ms = new MemoryStream())
            {
                int read;
                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
                {
                    ms.Write(buffer, 0, read);
                }
                return ms.ToArray();
            }
        }
    }
}

Enjoy!

What is the difference between Numpy's array() and asarray() functions?

The difference can be demonstrated by this example:

  1. generate a matrix

    >>> A = numpy.matrix(numpy.ones((3,3)))
    >>> A
    matrix([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])
    
  2. use numpy.array to modify A. Doesn't work because you are modifying a copy

    >>> numpy.array(A)[2]=2
    >>> A
    matrix([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])
    
  3. use numpy.asarray to modify A. It worked because you are modifying A itself

    >>> numpy.asarray(A)[2]=2
    >>> A
    matrix([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 2.,  2.,  2.]])
    

Hope this helps!

How to place the ~/.composer/vendor/bin directory in your PATH?

To solve this problem make sure you find the path of composer.phar first

example mine is something like this

alias composer="php /Users/Your-username/composer.phar"

Go to cd Users > Your user > Command ls and see if composer.phar is there if yes then add the above line to your .bash_profile. Make sure you change the username to your own.

Hope this help you out

Calendar Recurring/Repeating Events - Best Storage Method

RRULE standard is built for exactly this requirement i.e. saving and understanding recurrences. Microsoft and google both use it in their calendar events. Please go through this document for more details. https://icalendar.org/iCalendar-RFC-5545/3-8-5-3-recurrence-rule.html

Convert string to datetime in vb.net

Pass the decode pattern to ParseExact

Dim d as string = "201210120956"
Dim dt = DateTime.ParseExact(d, "yyyyMMddhhmm", Nothing)

ParseExact is available only from Net FrameWork 2.0.
If you are still on 1.1 you could use Parse, but you need to provide the IFormatProvider adequate to your string

How do I get the coordinates of a mouse click on a canvas element?

I recommend this link- http://miloq.blogspot.in/2011/05/coordinates-mouse-click-canvas.html

<style type="text/css">

  #canvas{background-color: #000;}

</style>

<script type="text/javascript">

  document.addEventListener("DOMContentLoaded", init, false);

  function init()
  {
    var canvas = document.getElementById("canvas");
    canvas.addEventListener("mousedown", getPosition, false);
  }

  function getPosition(event)
  {
    var x = new Number();
    var y = new Number();
    var canvas = document.getElementById("canvas");

    if (event.x != undefined && event.y != undefined)
    {
      x = event.x;
      y = event.y;
    }
    else // Firefox method to get the position
    {
      x = event.clientX + document.body.scrollLeft +
          document.documentElement.scrollLeft;
      y = event.clientY + document.body.scrollTop +
          document.documentElement.scrollTop;
    }

    x -= canvas.offsetLeft;
    y -= canvas.offsetTop;

    alert("x: " + x + "  y: " + y);
  }

</script>

How do I output the results of a HiveQL query to CSV?

Just to cover more following steps after kicking off the query: INSERT OVERWRITE LOCAL DIRECTORY '/home/lvermeer/temp' ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' select books from table;

In my case, the generated data under temp folder is in deflate format, and it looks like this:

$ ls
000000_0.deflate  
000001_0.deflate  
000002_0.deflate  
000003_0.deflate  
000004_0.deflate  
000005_0.deflate  
000006_0.deflate  
000007_0.deflate

Here's the command to unzip the deflate files and put everything into one csv file:

hadoop fs -text "file:///home/lvermeer/temp/*" > /home/lvermeer/result.csv

SQL injection that gets around mysql_real_escape_string()

TL;DR

mysql_real_escape_string() will provide no protection whatsoever (and could furthermore munge your data) if:

  • MySQL's NO_BACKSLASH_ESCAPES SQL mode is enabled (which it might be, unless you explicitly select another SQL mode every time you connect); and

  • your SQL string literals are quoted using double-quote " characters.

This was filed as bug #72458 and has been fixed in MySQL v5.7.6 (see the section headed "The Saving Grace", below).

This is another, (perhaps less?) obscure EDGE CASE!!!

In homage to @ircmaxell's excellent answer (really, this is supposed to be flattery and not plagiarism!), I will adopt his format:

The Attack

Starting off with a demonstration...

mysql_query('SET SQL_MODE="NO_BACKSLASH_ESCAPES"'); // could already be set
$var = mysql_real_escape_string('" OR 1=1 -- ');
mysql_query('SELECT * FROM test WHERE name = "'.$var.'" LIMIT 1');

This will return all records from the test table. A dissection:

  1. Selecting an SQL Mode

    mysql_query('SET SQL_MODE="NO_BACKSLASH_ESCAPES"');
    

    As documented under String Literals:

    There are several ways to include quote characters within a string:

    • A “'” inside a string quoted with “'” may be written as “''”.

    • A “"” inside a string quoted with “"” may be written as “""”.

    • Precede the quote character by an escape character (“\”).

    • A “'” inside a string quoted with “"” needs no special treatment and need not be doubled or escaped. In the same way, “"” inside a string quoted with “'” needs no special treatment.

    If the server's SQL mode includes NO_BACKSLASH_ESCAPES, then the third of these options—which is the usual approach adopted by mysql_real_escape_string()—is not available: one of the first two options must be used instead. Note that the effect of the fourth bullet is that one must necessarily know the character that will be used to quote the literal in order to avoid munging one's data.

  2. The Payload

    " OR 1=1 -- 
    

    The payload initiates this injection quite literally with the " character. No particular encoding. No special characters. No weird bytes.

  3. mysql_real_escape_string()

    $var = mysql_real_escape_string('" OR 1=1 -- ');
    

    Fortunately, mysql_real_escape_string() does check the SQL mode and adjust its behaviour accordingly. See libmysql.c:

    ulong STDCALL
    mysql_real_escape_string(MYSQL *mysql, char *to,const char *from,
                 ulong length)
    {
      if (mysql->server_status & SERVER_STATUS_NO_BACKSLASH_ESCAPES)
        return escape_quotes_for_mysql(mysql->charset, to, 0, from, length);
      return escape_string_for_mysql(mysql->charset, to, 0, from, length);
    }
    

    Thus a different underlying function, escape_quotes_for_mysql(), is invoked if the NO_BACKSLASH_ESCAPES SQL mode is in use. As mentioned above, such a function needs to know which character will be used to quote the literal in order to repeat it without causing the other quotation character from being repeated literally.

    However, this function arbitrarily assumes that the string will be quoted using the single-quote ' character. See charset.c:

    /*
      Escape apostrophes by doubling them up
    
    // [ deletia 839-845 ]
    
      DESCRIPTION
        This escapes the contents of a string by doubling up any apostrophes that
        it contains. This is used when the NO_BACKSLASH_ESCAPES SQL_MODE is in
        effect on the server.
    
    // [ deletia 852-858 ]
    */
    
    size_t escape_quotes_for_mysql(CHARSET_INFO *charset_info,
                                   char *to, size_t to_length,
                                   const char *from, size_t length)
    {
    // [ deletia 865-892 ]
    
        if (*from == '\'')
        {
          if (to + 2 > to_end)
          {
            overflow= TRUE;
            break;
          }
          *to++= '\'';
          *to++= '\'';
        }
    

    So, it leaves double-quote " characters untouched (and doubles all single-quote ' characters) irrespective of the actual character that is used to quote the literal! In our case $var remains exactly the same as the argument that was provided to mysql_real_escape_string()—it's as though no escaping has taken place at all.

  4. The Query

    mysql_query('SELECT * FROM test WHERE name = "'.$var.'" LIMIT 1');
    

    Something of a formality, the rendered query is:

    SELECT * FROM test WHERE name = "" OR 1=1 -- " LIMIT 1
    

As my learned friend put it: congratulations, you just successfully attacked a program using mysql_real_escape_string()...

The Bad

mysql_set_charset() cannot help, as this has nothing to do with character sets; nor can mysqli::real_escape_string(), since that's just a different wrapper around this same function.

The problem, if not already obvious, is that the call to mysql_real_escape_string() cannot know with which character the literal will be quoted, as that's left to the developer to decide at a later time. So, in NO_BACKSLASH_ESCAPES mode, there is literally no way that this function can safely escape every input for use with arbitrary quoting (at least, not without doubling characters that do not require doubling and thus munging your data).

The Ugly

It gets worse. NO_BACKSLASH_ESCAPES may not be all that uncommon in the wild owing to the necessity of its use for compatibility with standard SQL (e.g. see section 5.3 of the SQL-92 specification, namely the <quote symbol> ::= <quote><quote> grammar production and lack of any special meaning given to backslash). Furthermore, its use was explicitly recommended as a workaround to the (long since fixed) bug that ircmaxell's post describes. Who knows, some DBAs might even configure it to be on by default as means of discouraging use of incorrect escaping methods like addslashes().

Also, the SQL mode of a new connection is set by the server according to its configuration (which a SUPER user can change at any time); thus, to be certain of the server's behaviour, you must always explicitly specify your desired mode after connecting.

The Saving Grace

So long as you always explicitly set the SQL mode not to include NO_BACKSLASH_ESCAPES, or quote MySQL string literals using the single-quote character, this bug cannot rear its ugly head: respectively escape_quotes_for_mysql() will not be used, or its assumption about which quote characters require repeating will be correct.

For this reason, I recommend that anyone using NO_BACKSLASH_ESCAPES also enables ANSI_QUOTES mode, as it will force habitual use of single-quoted string literals. Note that this does not prevent SQL injection in the event that double-quoted literals happen to be used—it merely reduces the likelihood of that happening (because normal, non-malicious queries would fail).

In PDO, both its equivalent function PDO::quote() and its prepared statement emulator call upon mysql_handle_quoter()—which does exactly this: it ensures that the escaped literal is quoted in single-quotes, so you can be certain that PDO is always immune from this bug.

As of MySQL v5.7.6, this bug has been fixed. See change log:

Functionality Added or Changed

Safe Examples

Taken together with the bug explained by ircmaxell, the following examples are entirely safe (assuming that one is either using MySQL later than 4.1.20, 5.0.22, 5.1.11; or that one is not using a GBK/Big5 connection encoding):

mysql_set_charset($charset);
mysql_query("SET SQL_MODE=''");
$var = mysql_real_escape_string('" OR 1=1 /*');
mysql_query('SELECT * FROM test WHERE name = "'.$var.'" LIMIT 1');

...because we've explicitly selected an SQL mode that doesn't include NO_BACKSLASH_ESCAPES.

mysql_set_charset($charset);
$var = mysql_real_escape_string("' OR 1=1 /*");
mysql_query("SELECT * FROM test WHERE name = '$var' LIMIT 1");

...because we're quoting our string literal with single-quotes.

$stmt = $pdo->prepare('SELECT * FROM test WHERE name = ? LIMIT 1');
$stmt->execute(["' OR 1=1 /*"]);

...because PDO prepared statements are immune from this vulnerability (and ircmaxell's too, provided either that you're using PHP=5.3.6 and the character set has been correctly set in the DSN; or that prepared statement emulation has been disabled).

$var  = $pdo->quote("' OR 1=1 /*");
$stmt = $pdo->query("SELECT * FROM test WHERE name = $var LIMIT 1");

...because PDO's quote() function not only escapes the literal, but also quotes it (in single-quote ' characters); note that to avoid ircmaxell's bug in this case, you must be using PHP=5.3.6 and have correctly set the character set in the DSN.

$stmt = $mysqli->prepare('SELECT * FROM test WHERE name = ? LIMIT 1');
$param = "' OR 1=1 /*";
$stmt->bind_param('s', $param);
$stmt->execute();

...because MySQLi prepared statements are safe.

Wrapping Up

Thus, if you:

  • use native prepared statements

OR

  • use MySQL v5.7.6 or later

OR

  • in addition to employing one of the solutions in ircmaxell's summary, use at least one of:

    • PDO;
    • single-quoted string literals; or
    • an explicitly set SQL mode that does not include NO_BACKSLASH_ESCAPES

...then you should be completely safe (vulnerabilities outside the scope of string escaping aside).

I want to vertical-align text in select box

Your best option will probably be to adjust the top padding & compare across browsers. It's not perfect, but I think it's as close as you can get.

padding-top:4px;

The amount of padding you need will depend on the font size.

Tip: If your font is set in px, set padding in px as well. If your font is set in em, set the padding in em too.

EDIT

These are the options I think you have, since vertical-align isn't consistant across the browsers.

A. Remove height attribute and let the browser handle it. This usually works the best for me.

 <style>
    select{
        border: 1px solid #ABADB3;
        margin: 0;
        padding: auto 0;
        font-size:14px;
    }
    </style>
    <select>
        <option>option 1</option>
        <option>number 2</option>
    </select>

B. Add top-padding to push down the text. (Pushed down the arrow in some browsers)

<style>
select{
    height: 28px !important;
    border: 1px solid #ABADB3;
    margin: 0;
    padding: 4px 0 0 0;
    font-size:14px;
}
</style>
<select>
    <option>option 1</option>
    <option>number 2</option>
</select>

C. You can make the font larger to try and match the select height a little nicer.

<style>
select{
    height: 28px !important;
    border: 1px solid #ABADB3;
    margin: 0;
    padding: 0 0 0 0;
    font-size:17px;
}
</style>
<select>
    <option>option 1</option>
    <option>number 2</option>
</select>

Using PUT method in HTML form

for people using laravel

<form method="post" ...>
@csrf
@method('put')
...
</form>

Search and replace a line in a file in Python

Using hamishmcn's answer as a template I was able to search for a line in a file that match my regex and replacing it with empty string.

import re 

fin = open("in.txt", 'r') # in file
fout = open("out.txt", 'w') # out file
for line in fin:
    p = re.compile('[-][0-9]*[.][0-9]*[,]|[-][0-9]*[,]') # pattern
    newline = p.sub('',line) # replace matching strings with empty string
    print newline
    fout.write(newline)
fin.close()
fout.close()

How do I style appcompat-v7 Toolbar like Theme.AppCompat.Light.DarkActionBar?

The recommended way to style the Toolbar for a Light.DarkActionBar clone would be to use Theme.AppCompat.Light.DarkActionbar as parent/app theme and add the following attributes to the style to hide the default ActionBar:

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
</style>

Then use the following as your Toolbar:

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
</android.support.design.widget.AppBarLayout>

For further modifications, you would create styles extending ThemeOverlay.AppCompat.Dark.ActionBar and ThemeOverlay.AppCompat.Light replacing the ones within AppBarLayout->android:theme and Toolbar->app:popupTheme. Also note that this will pick up your ?attr/colorPrimary if you have set it in your main style so you might get a different background color.

You will find a good example of this is in the current project template with an Empty Activity of Android Studio (1.4+).

How do I ignore files in a directory in Git?

A sample .gitignore file can look like one below for a Android Studio project

# built application files
*.apk
*.ap_

# files for the dex VM
*.dex

# Java class files
*.class

# generated files
bin/
gen/

# Local configuration file (sdk path, etc)
local.properties


#Eclipse
*.pydevproject
.project
.metadata
bin/**
tmp/**
tmp/**/*
*.tmp
*.bak
*.swp
*~.nib
local.properties
.classpath
.settings/
.loadpath
YourProjetcName/.gradle/
YourProjetcName/app/build/
*/YourProjetcName/.gradle/
*/YourProjetcName/app/build/

# External tool builders
.externalToolBuilders/

# Locally stored "Eclipse launch configurations"
*.launch

# CDT-specific
.cproject

# PDT-specific
.buildpath

# Proguard folder generated by Eclipse
proguard/

# Intellij project files
*.iml
*.ipr
*.iws
.idea/
/build
build/
*/build/
*/*/build/
*/*/*/build/
*.bin
*.lock
YourProjetcName/app/build/
.gradle
/local.properties
/.idea/workspace.xml
/.idea/libraries
.DS_Store
.gradle/
app/build/
*app/build/

# Local configuration file (sdk path, etc)
local.properties
/YourProjetcName/build/intermediates/lint-cache/api-versions-6-23.1.bin
appcompat_v7_23_1_1.xml
projectFilesBackup
build.gradle
YourProjetcName.iml
YourProjetcName.iml
gradlew
gradlew.bat
local.properties
settings.gradle
.gradle
.idea
android
build
gradle

How to sort a list/tuple of lists/tuples by the element at a given index?

I just want to add to Stephen's answer if you want to sort the array from high to low, another way other than in the comments above is just to add this to the line:

reverse = True

and the result will be as follows:

data.sort(key=lambda tup: tup[1], reverse=True)

Converting an integer to a string in PHP

$num = 10;
"'".$num."'"

Try this

Laravel - Route::resource vs Route::controller

RESTful Resource controller

A RESTful resource controller sets up some default routes for you and even names them.

Route::resource('users', 'UsersController');

Gives you these named routes:

Verb          Path                        Action  Route Name
GET           /users                      index   users.index
GET           /users/create               create  users.create
POST          /users                      store   users.store
GET           /users/{user}               show    users.show
GET           /users/{user}/edit          edit    users.edit
PUT|PATCH     /users/{user}               update  users.update
DELETE        /users/{user}               destroy users.destroy

And you would set up your controller something like this (actions = methods)

class UsersController extends BaseController {

    public function index() {}

    public function show($id) {}

    public function store() {}

}

You can also choose what actions are included or excluded like this:

Route::resource('users', 'UsersController', [
    'only' => ['index', 'show']
]);

Route::resource('monkeys', 'MonkeysController', [
    'except' => ['edit', 'create']
]);

API Resource controller

Laravel 5.5 added another method for dealing with routes for resource controllers. API Resource Controller acts exactly like shown above, but does not register create and edit routes. It is meant to be used for ease of mapping routes used in RESTful APIs - where you typically do not have any kind of data located in create nor edit methods.

Route::apiResource('users', 'UsersController');

RESTful Resource Controller documentation


Implicit controller

An Implicit controller is more flexible. You get routed to your controller methods based on the HTTP request type and name. However, you don't have route names defined for you and it will catch all subfolders for the same route.

Route::controller('users', 'UserController');

Would lead you to set up the controller with a sort of RESTful naming scheme:

class UserController extends BaseController {

    public function getIndex()
    {
        // GET request to index
    }

    public function getShow($id)
    {
        // get request to 'users/show/{id}'
    }

    public function postStore()
    {
        // POST request to 'users/store'
    }

}

Implicit Controller documentation


It is good practice to use what you need, as per your preference. I personally don't like the Implicit controllers, because they can be messy, don't provide names and can be confusing when using php artisan routes. I typically use RESTful Resource controllers in combination with explicit routes.

$watch'ing for data changes in an Angular directive

You need to enable deep object dirty checking. By default angular only checks the reference of the top level variable that you watch.

App.directive('d3Visualization', function() {
    return {
        restrict: 'E',
        scope: {
            val: '='
        },
        link: function(scope, element, attrs) {
            scope.$watch('val', function(newValue, oldValue) {
                if (newValue)
                    console.log("I see a data change!");
            }, true);
        }
    }
});

see Scope. The third parameter of the $watch function enables deep dirty checking if it's set to true.

Take note that deep dirty checking is expensive. So if you just need to watch the children array instead of the whole data variable the watch the variable directly.

scope.$watch('val.children', function(newValue, oldValue) {}, true);

version 1.2.x introduced $watchCollection

Shallow watches the properties of an object and fires whenever any of the properties change (for arrays, this implies watching the array items; for object maps, this implies watching the properties)

scope.$watchCollection('val.children', function(newValue, oldValue) {});

Java - Getting Data from MySQL database

  • First, Download MySQL connector jar file, This is the latest jar file as of today [mysql-connector-java-8.0.21].

  • Add the Jar file to your workspace [build path].

  • Then Create a new Connection object from the DriverManager class, so you could use this Connection object to execute queries.

  • Define the database name, userName, and Password for your connection.

  • Use the resultSet to get the data based one the column name from your database table.

Sample code is here:

public class JdbcMySQLExample{

public static void main(String[] args) {

    String url = "jdbc:mysql://localhost:3306/YOUR_DB_NAME?useSSL=false";
    String user = "root";
    String password = "root";
    
    String query = "SELECT * from YOUR_TABLE_NAME";

    try (Connection con = DriverManager.getConnection(url, user, password);
        Statement st = con.createStatement();
        ResultSet rs = st.executeQuery(query)) {

        if (rs.next()) {
            
            System.out.println(rs.getString(1));
        }

    } catch (SQLException ex) {
          System.out.println(ex);
       
    } 
}

javac: invalid target release: 1.8

Your javac is not pointing to correct java.

Check where your javac is pointing using following command -

update-alternatives --config javac

If it is not pointed to the javac you want to compile with, point it to "/JAVA8_HOME/bin/javac", or which ever java you want to compile with.

Change directory in PowerShell

To go directly to that folder, you can use the Set-Location cmdlet or cd alias:

Set-Location "Q:\My Test Folder"

Format certain floating dataframe columns into percentage in pandas

replace the values using the round function, and format the string representation of the percentage numbers:

df['var2'] = pd.Series([round(val, 2) for val in df['var2']], index = df.index)
df['var3'] = pd.Series(["{0:.2f}%".format(val * 100) for val in df['var3']], index = df.index)

The round function rounds a floating point number to the number of decimal places provided as second argument to the function.

String formatting allows you to represent the numbers as you wish. You can change the number of decimal places shown by changing the number before the f.

p.s. I was not sure if your 'percentage' numbers had already been multiplied by 100. If they have then clearly you will want to change the number of decimals displayed, and remove the hundred multiplication.

How to add a string to a string[] array? There's no .Add function

Alternatively, you can resize the array.

Array.Resize(ref array, array.Length + 1);
array[array.Length - 1] = "new string";

OpenCV NoneType object has no attribute shape

I faced the same problem today, please check for the path of the image as mentioned by cybseccrypt. After imread, try printing the image and see. If you get a value, it means the file is open.

Code:

img_src = cv2.imread('/home/deepak/python-workout/box2.jpg',0) print img_src

Hope this helps!

How to know that a string starts/ends with a specific string in jQuery?

You do not really need jQuery for such tasks. In the ES6 specification they already have out of the box methods startsWith and endsWith.

var str = "To be, or not to be, that is the question.";
alert(str.startsWith("To be"));         // true
alert(str.startsWith("not to be"));     // false
alert(str.startsWith("not to be", 10)); // true

var str = "To be, or not to be, that is the question.";
alert( str.endsWith("question.") );  // true
alert( str.endsWith("to be") );      // false
alert( str.endsWith("to be", 19) );  // true

Currently available in FF and Chrome. For old browsers you can use their polyfills or substr

How to edit incorrect commit message in Mercurial?

In TortoiseHg, right-click on the revision you want to modify. Choose Modify History->Import MQ. That will convert all the revisions up to and including the selected revision from Mercurial changesets into Mercurial Queue patches. Select the Patch you want to modify the message for, and it should automatically change the screen to the MQ editor. Edit the message which is in the middle of the screen, then click QRefresh. Finally, right click on the patch and choose Modify History->Finish Patch, which will convert it from a patch back into a change set.

Oh, this assumes that MQ is an active extension for TortoiseHG on this repository. If not, you should be able to click File->Settings, click Extensions, and click the mq checkbox. It should warn you that you have to close TortoiseHg before the extension is active, so close and reopen.

How can I make an svg scale with its parent container?

After like 48 hours of research, I ended up doing this to get proportional scaling:

NOTE: This sample is written with React. If you aren't using that, change the camel case stuff back to hyphens (ie: change backgroundColor to background-color and change the style Object back to a String).

<div
  style={{
    backgroundColor: 'lightpink',
    resize: 'horizontal',
    overflow: 'hidden',
    width: '1000px',
    height: 'auto',
  }}
>
  <svg
    width="100%"
    viewBox="113 128 972 600"
    preserveAspectRatio="xMidYMid meet"
  >
    <g> ... </g>
  </svg>
</div>

Here's what is happening in the above sample code:

VIEWBOX

MDN: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/viewBox

min-x, min-y, width and height

ie: viewbox="0 0 1000 1000"

Viewbox is an important attribute because it basically tells the SVG what size to draw and where. If you used CSS to make the SVG 1000x1000 px but your viewbox was 2000x2000, you would see the top-left quarter of your SVG.

The first two numbers, min-x and min-y, determine if the SVG should be offset inside the viewbox.

My SVG needs to shift up/down or left/right

Examine this: viewbox="50 50 450 450"

The first two numbers will shift your SVG left 50px and up 50px, and the second two numbers are the viewbox size: 450x450 px. If your SVG is 500x500 but it has some extra padding on it, you can manipulate those numbers to move it around inside the "viewbox".

Your goal at this point is to change one of those numbers and see what happens.

You can also completely omit the viewbox, but then your milage will vary depending on every other setting you have at the time. In my experience, you will encounter issues with preserving aspect ratio because the viewbox helps define the aspect ratio.

PRESERVE ASPECT RATIO

MDN: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/preserveAspectRatio

Based on my research, there are lots of different aspect ratio settings, but the default one is called xMidYMid meet. I put it on mine to explicitly remind myself. xMidYMid meet makes it scale proportionately based on the midpoint X and Y. This means it stays centered in the viewbox.

WIDTH

MDN: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/width

Look at my example code above. Notice how I set only width, no height. I set it to 100% so it fills the container it is in. This is what is probably contributing the most to answering this Stack Overflow question.

You can change it to whatever pixel value you want, but I'd recommend using 100% like I did to blow it up to max size and then control it with CSS via the parent container. I recommend this because you will get "proper" control. You can use media queries and you can control the size without crazy JavaScript.

SCALING WITH CSS

Look at my example code above again. Notice how I have these properties:

resize: 'horizontal', // you can safely omit this
overflow: 'hidden',   // if you use resize, use this to fix weird scrollbar appearance
width: '1000px',
height: 'auto',

This is additional, but it shows you how to allow the user to resize the SVG while maintaining the proper aspect ratio. Because the SVG maintains its own aspect ratio, you only need to make width resizable on the parent container, and it will resize as desired.

We leave height alone and/or set it to auto, and we control the resizing with width. I picked width because it is often more meaningful due to responsive designs.

Here is an image of these settings being used:

enter image description here

If you read every solution in this question and are still confused or don't quite see what you need, check out this link here. I found it very helpful:

https://css-tricks.com/scale-svg/

It's a massive article, but it breaks down pretty much every possible way to manipulate an SVG, with or without CSS. I recommend reading it while casually drinking a coffee or your choice of select liquids.

C# string does not contain possible?

Option with a regexp if you want to discriminate between Mango and Mangosteen.

var reg = new Regex(@"\b(pineapple|mango)\b", 
                       RegexOptions.IgnoreCase | RegexOptions.Multiline);
   if (!reg.Match(compareString).Success)
      ...

Convert JSON format to CSV format for MS Excel

I'm not sure what you're doing, but this will go from JSON to CSV using JavaScript. This is using the open source JSON library, so just download JSON.js into the same folder you saved the code below into, and it will parse the static JSON value in json3 into CSV and prompt you to download/open in Excel.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>JSON to CSV</title>
    <script src="scripts/json.js" type="text/javascript"></script>
    <script type="text/javascript">
    var json3 = { "d": "[{\"Id\":1,\"UserName\":\"Sam Smith\"},{\"Id\":2,\"UserName\":\"Fred Frankly\"},{\"Id\":1,\"UserName\":\"Zachary Zupers\"}]" }

    DownloadJSON2CSV(json3.d);

    function DownloadJSON2CSV(objArray)
    {
        var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;

        var str = '';

        for (var i = 0; i < array.length; i++) {
            var line = '';

            for (var index in array[i]) {
                line += array[i][index] + ',';
            }

            // Here is an example where you would wrap the values in double quotes
            // for (var index in array[i]) {
            //    line += '"' + array[i][index] + '",';
            // }

            line.slice(0,line.Length-1); 

            str += line + '\r\n';
        }
        window.open( "data:text/csv;charset=utf-8," + escape(str))
    }

    </script>

</head>
<body>
    <h1>This page does nothing....</h1>
</body>
</html>

How can I get argv[] as int?

argv[1] is a pointer to a string.

You can print the string it points to using printf("%s\n", argv[1]);

To get an integer from a string you have first to convert it. Use strtol to convert a string to an int.

#include <errno.h>   // for errno
#include <limits.h>  // for INT_MAX
#include <stdlib.h>  // for strtol
 
char *p;
int num;

errno = 0;
long conv = strtol(argv[1], &p, 10);

// Check for errors: e.g., the string does not represent an integer
// or the integer is larger than int
if (errno != 0 || *p != '\0' || conv > INT_MAX) {
    // Put here the handling of the error, like exiting the program with
    // an error message
} else {
    // No error
    num = conv;    
    printf("%d\n", num);
}

How to convert map to url query string?

The most robust one I saw off-the-shelf is the URLEncodedUtils class from Apache Http Compoments (HttpClient 4.0).

The method URLEncodedUtils.format() is what you need.

It doesn't use map so you can have duplicate parameter names, like,

  a=1&a=2&b=3

Not that I recommend this kind of use of parameter names.

Export table from database to csv file

Some ideas:

From SQL Server Management Studio

 1. Run a SELECT statement to filter your data
 2. Click on the top-left corner to select all rows
 3. Right-click to copy all the selected
 4. Paste the copied content on Microsoft Excel
 5. Save as CSV

Using SQLCMD (Command Prompt)

Example:

From the command prompt, you can run the query and export it to a file:

sqlcmd -S . -d DatabaseName -E -s, -W -Q "SELECT * FROM TableName" > C:\Test.csv

Do not quote separator use just -s, and not quotes -s',' unless you want to set quote as separator.

More information here: ExcelSQLServer

Notes:

  • This approach will have the "Rows affected" information in the bottom of the file, but you can get rid of this by using the "SET NOCOUNT ON" in the query itself.

  • You may run a stored procedure instead of the actual query (e.g. "EXEC Database.dbo.StoredProcedure")

  • You can use any programming language or even a batch file to automate this

Using BCP (Command Prompt)

Example:

bcp "SELECT * FROM Database.dbo.Table" queryout C:\Test.csv -c -t',' -T -S .\SQLEXPRESS

It is important to quote the comma separator as -t',' vs just -t,

More information here: bcp Utility

Notes:

  • As per when using SQLCMD, you can run stored procedures instead of the actual queries
  • You can use any programming language or a batch file to automate this

Hope this helps.

What is JavaScript garbage collection?

Reference types do not store the object directly into the variable to which it is assigned, so the object variable in the example below, doesn’t actually contain the object instance. Instead, it holds a pointer (or reference) to the location in memory, where the object exists.

var object = new Object();

if you assign one reference typed variable to another, each variable gets a copy of the pointer, and both still reference to the same object in memory.

var object1 = new Object();
var object2 = object1;

Two variables pointing to one object

JavaScript is a garbage-collected language, so you don’t really need to worry about memory allocations when you use reference types. However, it’s best to dereference objects that you no longer need so that the garbage collector can free up that memory. The best way to do this is to set the object variable to null.

var object1 = new Object();
// do something
object1 = null; // dereference

Dereferencing objects is especially important in very large applications that use millions of objects.

from The Principles of Object-Oriented JavaScript - NICHOLAS C. ZAKAS

What is the Regular Expression For "Not Whitespace and Not a hyphen"

It can be done much easier:

\S which equals [^ \t\r\n\v\f]

Format cell color based on value in another sheet and cell

I'm using Excel 2003 -

The problem with using conditional formatting here is that you can't reference another worksheet or workbook in your conditions. What you can to do is set some column on sheet 1 equal to the appropriate column on sheet 2 (in your example =Sheet2!B6). I used Column F in my example below. Then you can use conditional formatting. Select the cell at Sheet 1, row , column 1 and then go to the conditional formatting menu. Choose "Formula Is" from the drop down and set the condition to "=$F$6=4". Click on the format button and then choose the Patterns tab. Choose the color you want and you're done.

You can use the format painter tool to apply conditional formatting to other cells, but be aware that by default Excel uses absolute references in the conditions. If you want them to be relative you'll need to remove the dollar signs from the condition.

You can have up to 3 conditions applied to a cell (use the add >> button at the bottom of the Conditional formatting dialog) so if the last row is fixed (for example, you know that it will always be row 10) you can use it as a condition to set the background color to none. Assuming that the last value you care about is in row 10 then (still assuming that you've set column F on sheet1 to the corresponding cells on sheet 2) then set the 1st condition to Formula Is =$F$10="" and the pattern to None. Make it the first condition and it will override any following conflicting statements.

Adding 'serial' to existing column in Postgres

Look at the following commands (especially the commented block).

DROP TABLE foo;
DROP TABLE bar;

CREATE TABLE foo (a int, b text);
CREATE TABLE bar (a serial, b text);

INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM generate_series(1, 5) i;

-- blocks of commands to turn foo into bar
CREATE SEQUENCE foo_a_seq;
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq');
ALTER TABLE foo ALTER COLUMN a SET NOT NULL;
ALTER SEQUENCE foo_a_seq OWNED BY foo.a;    -- 8.2 or later

SELECT MAX(a) FROM foo;
SELECT setval('foo_a_seq', 5);  -- replace 5 by SELECT MAX result

INSERT INTO foo (b) VALUES('teste');
INSERT INTO bar (b) VALUES('teste');

SELECT * FROM foo;
SELECT * FROM bar;

VBA procedure to import csv file into access

The easiest way to do it is to link the CSV-file into the Access database as a table. Then you can work on this table as if it was an ordinary access table, for instance by creating an appropriate query based on this table that returns exactly what you want.

You can link the table either manually or with VBA like this

DoCmd.TransferText TransferType:=acLinkDelim, TableName:="tblImport", _
    FileName:="C:\MyData.csv", HasFieldNames:=true

UPDATE

Dim db As DAO.Database

' Re-link the CSV Table
Set db = CurrentDb
On Error Resume Next:   db.TableDefs.Delete "tblImport":   On Error GoTo 0
db.TableDefs.Refresh
DoCmd.TransferText TransferType:=acLinkDelim, TableName:="tblImport", _
    FileName:="C:\MyData.csv", HasFieldNames:=true
db.TableDefs.Refresh

' Perform the import
db.Execute "INSERT INTO someTable SELECT col1, col2, ... FROM tblImport " _
   & "WHERE NOT F1 IN ('A1', 'A2', 'A3')"
db.Close:   Set db = Nothing

How to count number of records per day?

select DateAdded, count(DateAdded) as num_records
from your_table
WHERE DateAdded >=dateadd(day,datediff(day,0,GetDate())- 7,0)
group by DateAdded
order by DateAdded

WCF error - There was no endpoint listening at

You do not define a binding in your service's config, so you are getting the default values for wsHttpBinding, and the default value for securityMode\transport for that binding is Message.

Try copying your binding configuration from the client's config to your service config and assign that binding to the endpoint via the bindingConfiguration attribute:

<bindings>
  <wsHttpBinding>
    <binding name="ota2010AEndpoint" 
             .......>
      <readerQuotas maxDepth="32" ... />
        <reliableSession ordered="true" .... />
          <security mode="Transport">
            <transport clientCredentialType="None" proxyCredentialType="None"
                       realm="" />
            <message clientCredentialType="Windows" negotiateServiceCredential="true"
                     establishSecurityContext="true" />
          </security>
    </binding>
  </wsHttpBinding>
</bindings>    

(Snipped parts of the config to save space in the answer).

<service name="Synxis" behaviorConfiguration="SynxisWCF">
    <endpoint address="" name="wsHttpEndpoint" 
              binding="wsHttpBinding" 
              bindingConfiguration="ota2010AEndpoint"
              contract="Synxis" />

This will then assign your defined binding (with Transport security) to the endpoint.

Convert MySql DateTime stamp into JavaScript's Date format

One liner for modern browsers (IE10+):

var d = new Date(Date.parse("2010-06-09 13:12:01"));
alert(d); // Wed Jun 09 2010 13:12:01 GMT+0100 (GMT Daylight Time)

And just for fun, here's a one-liner that will work across older browsers (now fixed):

new (Function.prototype.bind.apply(Date, [null].concat("2010-06-09 13:12:01".split(/[\s:-]/)).map(function(v,i){return i==2?--v:v}) ));
alert(d); // Wed Jun 09 2010 13:12:01 GMT+0100 (GMT Daylight Time)

SqlServer: Login failed for user

In my case I have configured as below in my springboot application.properties file then I am able to connect to the sqlserver database using service account:

url=jdbc:sqlserver://SERVER_NAME:PORT_NUMBER;databaseName=DATABASE_NAME;sendStringParametersAsUnicode=false;multiSubnetFailover=true;integratedSecurity=true
    jdbcUrl=${url}
    username=YourDomain\\$SERVICE-ACCOUNT-USER-NAME
    password=
    hikari.connection-timeout=60000
    hikari.maximum-pool-size=5
    driver-class-name=com.microsoft.sqlserver.jdbc.SQLServerDriver

How can a add a row to a data frame in R?

There's now add_row() from the tibble or tidyverse packages.

library(tidyverse)
df %>% add_row(hello = "hola", goodbye = "ciao")

Unspecified columns get an NA.

Suppress output of a function

Making Hadley's comment to an answer (hope to make it better visible). Use of apply family without printing is possible with use of the plyr package

x <- 1:2
lapply(x, function(x) x + 1)
#> [[1]]
#> [1] 2
#> 
#> [[2]]
#> [1] 3

plyr::l_ply(x, function(x) x + 1)

Created on 2020-05-19 by the reprex package (v0.3.0)

Python 2.7.10 error "from urllib.request import urlopen" no module named request

Change

from urllib.request import urlopen

to

from urllib import urlopen

I was able to solve this problem by changing like this. For Python2.7 in macOS10.14

How to present UIAlertController when not in a view controller?

I use this code with some little personal variations in my AppDelegate class

-(UIViewController*)presentingRootViewController
{
    UIViewController *vc = self.window.rootViewController;
    if ([vc isKindOfClass:[UINavigationController class]] ||
        [vc isKindOfClass:[UITabBarController class]])
    {
        // filter nav controller
        vc = [AppDelegate findChildThatIsNotNavController:vc];
        // filter tab controller
        if ([vc isKindOfClass:[UITabBarController class]]) {
            UITabBarController *tbc = ((UITabBarController*)vc);
            if ([tbc viewControllers].count > 0) {
                vc = [tbc viewControllers][tbc.selectedIndex];
                // filter nav controller again
                vc = [AppDelegate findChildThatIsNotNavController:vc];
            }
        }
    }
    return vc;
}
/**
 *   Private helper
 */
+(UIViewController*)findChildThatIsNotNavController:(UIViewController*)vc
{
    if ([vc isKindOfClass:[UINavigationController class]]) {
        if (((UINavigationController *)vc).viewControllers.count > 0) {
            vc = [((UINavigationController *)vc).viewControllers objectAtIndex:0];
        }
    }
    return vc;
}

get name of a variable or parameter

What you are passing to GETNAME is the value of myInput, not the definition of myInput itself. The only way to do that is with a lambda expression, for example:

var nameofVar = GETNAME(() => myInput);

and indeed there are examples of that available. However! This reeks of doing something very wrong. I would propose you rethink why you need this. It is almost certainly not a good way of doing it, and forces various overheads (the capture class instance, and the expression tree). Also, it impacts the compiler: without this the compiler might actually have chosen to remove that variable completely (just using the stack without a formal local).

Colon (:) in Python list index

: is the delimiter of the slice syntax to 'slice out' sub-parts in sequences , [start:end]

[1:5] is equivalent to "from 1 to 5" (5 not included)
[1:] is equivalent to "1 to end"
[len(a):] is equivalent to "from length of a to end"

Watch https://youtu.be/tKTZoB2Vjuk?t=41m40s at around 40:00 he starts explaining that.

Works with tuples and strings, too.

Why can't radio buttons be "readonly"?

JavaScript way - this worked for me.

<script>
$(document).ready(function() {
   $('#YourTableId').find('*').each(function () { $(this).attr("disabled", true); });
});
</script>

Reason:

  1. $('#YourTableId').find('*') -> this returns all the tags.

  2. $('#YourTableId').find('*').each(function () { $(this).attr("disabled", true); }); iterates over all objects captured in this and disable input tags.

Analysis (Debugging):

  1. form:radiobutton is internally considered as an "input" tag.

  2. Like in the above function(), if you try printing document.write(this.tagName);

  3. Wherever, in tags it finds radio buttons, it returns an input tag.

So, above code line can be more optimized for radio button tags, by replacing * with input: $('#YourTableId').find('input').each(function () { $(this).attr("disabled", true); });

How to check if a date is in a given range?

I found this method the easiest:

$start_date = '2009-06-17';
$end_date = '2009-09-05';
$date_from_user = '2009-08-28';

$start_date = date_create($start_date);
$date_from_user = date_create($date_from_user);
$end_date = date_create($end_date);

$interval1 = date_diff($start_date, $date_from_user);
$interval2 = date_diff($end_date, $date_from_user);

if($interval1->invert == 0){
  if($interval2->invert == 1){

     // if it lies between start date and end date execute this code

  }
}

Preventing console window from closing on Visual Studio C/C++ Console application

Currently there is no way to do this with apps running in WSL2. However there are two work-arounds:

  1. The debug window retains the contents of the WSL shell window that closed.

  2. The window remains open if your application returns a non-zero return code, so you could return non-zero in debug builds for example.

How to cast DATETIME as a DATE in mysql?

Use DATE() function:

select * from follow_queue group by DATE(follow_date)

How to delete Certain Characters in a excel 2010 cell

Replace [ with nothing, then ] with nothing.

How to convert text to binary code in JavaScript?

this seems to be the simplified version

Array.from('abc').map((each)=>each.charCodeAt(0).toString(2)).join(" ")

Python class returning value

Use __new__ to return value from a class.

As others suggest __repr__,__str__ or even __init__ (somehow) CAN give you what you want, But __new__ will be a semantically better solution for your purpose since you want the actual object to be returned and not just the string representation of it.

Read this answer for more insights into __str__ and __repr__ https://stackoverflow.com/a/19331543/4985585

class MyClass():
    def __new__(cls):
        return list() #or anything you want

>>> MyClass()
[]   #Returns a true list not a repr or string

Ionic 2: Cordova is not available. Make sure to include cordova.js or run in a device/simulator (running in emulator)

I also had this same problem.

I build .apk file of the project and installed it into mobile(android) and got it working

Can a normal Class implement multiple interfaces?

It is true that a java class can implement multiple interfaces at the same time, but there is a catch here. If in a class, you are trying to implement two java interfaces, which contains methods with same signature but diffrent return type, in that case you will get compilation error.

interface One
{
    int m1();
}
interface Two
{
    float m1();
}
public class MyClass implements One, Two{
    int m1() {}
    float m1() {}
    public static void main(String... args) {

    }
}

output :

prog.java:14: error: method m1() is already defined in class MyClass
    public float m1() {}
                 ^
prog.java:11: error: MyClass is not abstract and does not override abstract method m1() in Two
public class MyClass implements One, Two{
       ^
prog.java:13: error: m1() in MyClass cannot implement m1() in Two
    public int m1() {}
               ^
  return type int is not compatible with float
3 errors

How to handle static content in Spring MVC?

If I understand your issue correctly, I think I have found a solution to your problem:

I had the same issue where raw output was shown with no css styles, javascripts or jquery files found.

I just added mappings to the "default" servlet. The following was added to the web.xml file:

 <servlet-mapping>
  <servlet-name>default</servlet-name>
  <url-pattern>*.css</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
    <servlet-name>default</servlet-name>
    <url-pattern>*.js</url-pattern>
 </servlet-mapping>

This should filter out the javascript and css file requests from the DispatcherRequest object.

Again, not sure if this is what you are after, but it worked for me. I think "default" is the name of the default servlet within JBoss. Not too sure what it is for other servers.

Error 80040154 (Class not registered exception) when initializing VCProjectEngineObject (Microsoft.VisualStudio.VCProjectEngine.dll)

There are not many good reasons this would fail, especially the regsvr32 step. Run dumpbin /exports on that dll. If you don't see DllRegisterServer then you've got a corrupt install. It should have more side-effects, you wouldn't be able to build C/C++ projects anymore.

One standard failure mode is running this on a 64-bit operating system. This is 32-bit unmanaged code, you would indeed get the 'class not registered' exception. Project + Properties, Build tab, change Platform Target to x86.

Listing contents of a bucket with boto3

If you want to pass the ACCESS and SECRET keys (which you should not do, because it is not secure):

from boto3.session import Session

ACCESS_KEY='your_access_key'
SECRET_KEY='your_secret_key'

session = Session(aws_access_key_id=ACCESS_KEY,
                  aws_secret_access_key=SECRET_KEY)
s3 = session.resource('s3')
your_bucket = s3.Bucket('your_bucket')

for s3_file in your_bucket.objects.all():
    print(s3_file.key)

How to change the plot line color from blue to black?

The usual way to set the line color in matplotlib is to specify it in the plot command. This can either be done by a string after the data, e.g. "r-" for a red line, or by explicitely stating the color argument.

import matplotlib.pyplot as plt

plt.plot([1,2,3], [2,3,1], "r-") # red line
plt.plot([1,2,3], [5,5,3], color="blue") # blue line

plt.show()

See also the plot command's documentation.

In case you already have a line with a certain color, you can change that with the lines2D.set_color() method.

line, = plt.plot([1,2,3], [4,5,3], color="blue")
line.set_color("black")


Setting the color of a line in a pandas plot is also best done at the point of creating the plot:

import matplotlib.pyplot as plt
import pandas as pd

df = pd.DataFrame({ "x" : [1,2,3,5], "y" : [3,5,2,6]})
df.plot("x", "y", color="r") #plot red line

plt.show()

If you want to change this color later on, you can do so by

plt.gca().get_lines()[0].set_color("black")

This will get you the first (possibly the only) line of the current active axes.
In case you have more axes in the plot, you could loop through them

for ax in plt.gcf().axes:
    ax.get_lines()[0].set_color("black")

and if you have more lines you can loop over them as well.

How to use SortedMap interface in Java?

I would use TreeMap, which implements SortedMap. It is designed exactly for that.

Example:

Map<Integer, String> map = new TreeMap<Integer, String>();

// Add Items to the TreeMap
map.put(1, "One");
map.put(2, "Two");
map.put(3, "Three");

// Iterate over them
for (Map.Entry<Integer, String> entry : map.entrySet()) {
    System.out.println(entry.getKey() + " => " + entry.getValue());
}

See the Java tutorial page for SortedMap.
And here a list of tutorials related to TreeMap.

How to count rows with SELECT COUNT(*) with SQLAlchemy?

If you are using the SQL Expression Style approach there is another way to construct the count statement if you already have your table object.

Preparations to get the table object. There are also different ways.

import sqlalchemy

database_engine = sqlalchemy.create_engine("connection string")

# Populate existing database via reflection into sqlalchemy objects
database_metadata = sqlalchemy.MetaData()
database_metadata.reflect(bind=database_engine)

table_object = database_metadata.tables.get("table_name") # This is just for illustration how to get the table_object                    

Issuing the count query on the table_object

query = table_object.count()
# This will produce something like, where id is a primary key column in "table_name" automatically selected by sqlalchemy
# 'SELECT count(table_name.id) AS tbl_row_count FROM table_name'

count_result = database_engine.scalar(query)

Django 1.7 - "No migrations to apply" when run migrate after makemigrations

This is a very confusing topic. django stores all applied migrations in a table called django_migrations. perform this sql ( i am using postgres . so in query tool section)

select * from django_migrations where app='your appname'  (app in which u have issue with).

This will list all applied migrations for that app.
Go to your app/migration folder and check all migrations . find the migration file associated with your error . file where your table was created or column added or modified.
look for the id of this migration file in django_migrations table( select * from django_migrations where app='your app') .

Then do :

delete from django_migrations where id='id of your migration';

delete multiple id's if you have multiple migrations file associated with your issue.

now reapply migrate

Python manage.py migrate yourappname

second option

  1. Drop tables in your app where you have issue.

  2. delete all migrations for that app from app/migrations folder.(don't delete init.py from that folder).

  3. now run

    python manage.py makemigrations appname

  4. now run

python manage.py migrate appname

how to display excel sheet in html page

You can upload it into Google Docs, and embed the Google Spreadsheet as detailed here: http://support.google.com/docs/bin/answer.py?hl=en&answer=55244

What is for Python what 'explode' is for PHP?

The alternative for explode in php is split.

The first parameter is the delimiter, the second parameter the maximum number splits. The parts are returned without the delimiter present (except possibly the last part). When the delimiter is None, all whitespace is matched. This is the default.

>>> "Rajasekar SP".split()
['Rajasekar', 'SP']

>>> "Rajasekar SP".split('a',2)
['R','j','sekar SP']

Relative path in HTML

The easiest way to solve this in pure HTML is to use the <base href="…"> element like so:

<base href="http://localhost/mywebsite/" />

Then all of the URLs in your HTML can just be this:

<a href="images/example.png">Link To Image</a>

Just change the <base href="…"> to match your server. The rest of the HTML paths will just fall in line and will be appended to that.

Add my custom http header to Spring RestTemplate request / extend RestTemplate

Add a "User-Agent" header to your request.

Some servers attempt to block spidering programs and scrapers from accessing their server because, in earlier days, requests did not send a user agent header.

You can either try to set a custom user agent value or use some value that identifies a Browser like "Mozilla/5.0 Firefox/26.0"

RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();

headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
headers.setContentType(MediaType.APPLICATION_JSON);
headers.add("user-agent", "Mozilla/5.0 Firefox/26.0");
headers.set("user-key", "your-password-123"); // optional - in case you auth in headers
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<Game[]> respEntity = restTemplate.exchange(url, HttpMethod.GET, entity, Game[].class);

logger.info(respEntity.toString());

How to set custom JsonSerializerSettings for Json.NET in ASP.NET Web API?

You can specify JsonSerializerSettings for each JsonConvert, and you can set a global default.

Single JsonConvert with an overload:

// Option #1.
JsonSerializerSettings config = new JsonSerializerSettings { ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore };
this.json = JsonConvert.SerializeObject(YourObject, Formatting.Indented, config);

// Option #2 (inline).
JsonConvert.SerializeObject(YourObject, Formatting.Indented,
    new JsonSerializerSettings() {
        ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore
    }
);

Global Setting with code in Application_Start() in Global.asax.cs:

JsonConvert.DefaultSettings = () => new JsonSerializerSettings {
     Formatting = Newtonsoft.Json.Formatting.Indented,
     ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore
};

Reference: https://github.com/JamesNK/Newtonsoft.Json/issues/78

Fuzzy matching using T-SQL

Since the first release of Master Data Services, you've got access to more advanced fuzzy logic algorithms than what SOUNDEX implements. So provided that you've got MDS installed, you'll be able to find a function called Similarity() in the mdq schema (MDS database).

More info on how it works: http://blog.hoegaerden.be/2011/02/05/finding-similar-strings-with-fuzzy-logic-functions-built-into-mds/

How do I toggle an ng-show in AngularJS based on a boolean?

It's worth noting that if you have a button in Controller A and the element you want to show in Controller B, you may need to use dot notation to access the scope variable across controllers.

For example, this will not work:

<div ng-controller="ControllerA">
  <a ng-click="isReplyFormOpen = !isReplyFormOpen">Reply</a>

  <div ng-controller="ControllerB">
    <div ng-show="isReplyFormOpen" id="replyForm">
    </div>
  </div>

</div>

To solve this, create a global variable (ie. in Controller A or your main Controller):

.controller('ControllerA', function ($scope) {
  $scope.global = {};
}

Then add a 'global' prefix to your click and show variables:

<div ng-controller="ControllerA">
  <a ng-click="global.isReplyFormOpen = !global.isReplyFormOpen">Reply</a>

  <div ng-controller="ControllerB">
    <div ng-show="global.isReplyFormOpen" id="replyForm">
    </div>
  </div>

</div>

For more detail, check out the Nested States & Nested Views in the Angular-UI documentation, watch a video, or read understanding scopes.

What does the arrow operator, '->', do in Java?

I believe, this arrow exists because of your IDE. IntelliJ IDEA does such thing with some code. This is called code folding. You can click at the arrow to expand it.

How to pass a value from one jsp to another jsp page?

Suppose we want to pass three values(u1,u2,u3) from say 'show.jsp' to another page say 'display.jsp' Make three hidden text boxes and a button that is click automatically(using javascript). //Code to written in 'show.jsp'

<body>
<form action="display.jsp" method="post">
 <input type="hidden" name="u1" value="<%=u1%>"/>
 <input type="hidden" name="u2" value="<%=u2%>" />
 <input type="hidden" name="u3" value="<%=u3%>" />
 <button type="hidden" id="qq" value="Login" style="display: none;"></button>
</form>
  <script type="text/javascript">
     document.getElementById("qq").click();
  </script>
</body>

// Code to be written in 'display.jsp'

 <% String u1 = request.getParameter("u1").toString();
    String u2 = request.getParameter("u2").toString();
    String u3 = request.getParameter("u3").toString();
 %>

If you want to use these variables of servlets in javascript then simply write

<script type="text/javascript">
 var a=<%=u1%>;
</script>

Hope it helps :)

I can't delete a remote master branch on git

To answer the question literally (since GitHub is not in the question title), also be aware of this post over on superuser. EDIT: Answer copied here in relevant part, slightly modified for clarity in square brackets:

You're getting rejected because you're trying to delete the branch that your origin has currently "checked out".

If you have direct access to the repo, you can just open up a shell [in the bare repo] directory and use good old git branch to see what branch origin is currently on. To change it to another branch, you have to use git symbolic-ref HEAD refs/heads/another-branch.

Class constants in python

Since Horse is a subclass of Animal, you can just change

print(Animal.SIZES[1])

with

print(self.SIZES[1])

Still, you need to remember that SIZES[1] means "big", so probably you could improve your code by doing something like:

class Animal:
    SIZE_HUGE="Huge"
    SIZE_BIG="Big"
    SIZE_MEDIUM="Medium"
    SIZE_SMALL="Small"

class Horse(Animal):
    def printSize(self):
        print(self.SIZE_BIG)

Alternatively, you could create intermediate classes: HugeAnimal, BigAnimal, and so on. That would be especially helpful if each animal class will contain different logic.

Could not find server 'server name' in sys.servers. SQL Server 2014

I figured out the issue. The linked server was created correctly. However, after the server was upgraded and switched the server name in sys.servers still had the old server name.

I had to drop the old server name and add the new server name to sys.servers on the new server

sp_dropserver 'Server_A'
GO
sp_addserver  'Server',local
GO

How to perform an SQLite query within an Android application?

This will return you the required cursor

Cursor cursor = db.query(TABLE_NAME, new String[] {"_id", "title", "title_raw"}, 
                "title_raw like " + "'%Smith%'", null, null, null, null);

Difference between <span> and <div> with text-align:center;?

Like other have said, span is an in-line element.

See here: http://www.w3.org/TR/CSS2/visuren.html

Additionally, you can make a span behave like a div by applying a

style="display: block; margin: 0px auto; text-align: center;"

How do I display a decimal value to 2 decimal places?

If you want it formatted with commas as well as a decimal point (but no currency symbol), such as 3,456,789.12...

decimalVar.ToString("n2");

Get the last element of a std::string

You could write a function template back that delegates to the member function for ordinary containers and a normal function that implements the missing functionality for strings:

template <typename C>
typename C::reference back(C& container)
{
    return container.back();
}

template <typename C>
typename C::const_reference back(const C& container)
{
    return container.back();
}

char& back(std::string& str)
{
    return *(str.end() - 1);
}

char back(const std::string& str)
{
    return *(str.end() - 1);
}

Then you can just say back(foo) without worrying whether foo is a string or a vector.

How to set a selected option of a dropdown list control using angular JS

This is the code what I used for the set selected value

_x000D_
_x000D_
countryList: any = [{ "value": "AF", "group": "A", "text": "Afghanistan"}, { "value": "AL", "group": "A", "text": "Albania"}, { "value": "DZ", "group": "A", "text": "Algeria"}, { "value": "AD", "group": "A", "text": "Andorra"}, { "value": "AO", "group": "A", "text": "Angola"}, { "value": "AR", "group": "A", "text": "Argentina"}, { "value": "AM", "group": "A", "text": "Armenia"}, { "value": "AW", "group": "A", "text": "Aruba"}, { "value": "AU", "group": "A", "text": "Australia"}, { "value": "AT", "group": "A", "text": "Austria"}, { "value": "AZ", "group": "A", "text": "Azerbaijan"}];_x000D_
 _x000D_
 _x000D_
 for (var j = 0; j < countryList.length; j++) {_x000D_
      //debugger_x000D_
      if (countryList[j].text == "Australia") {_x000D_
          console.log(countryList[j].text); _x000D_
          countryList[j].isSelected = 'selected';_x000D_
      }_x000D_
      }
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.7.5/angular.min.js"></script>_x000D_
<label>Country</label>_x000D_
<select class="custom-select col-12" id="Country" name="Country"   >_x000D_
<option value="0" selected>Choose...</option>_x000D_
<option *ngFor="let country of countryList" value="{{country.text}}" selected="{{country.isSelected}}"   > {{country.text}}</option>_x000D_
</select>
_x000D_
_x000D_
_x000D_

try this on an angular framework

correct way to use super (argument passing)

As explained in Python's super() considered super, one way is to have class eat the arguments it requires, and pass the rest on. Thus, when the call-chain reaches object, all arguments have been eaten, and object.__init__ will be called without arguments (as it expects). So your code should look like this:

class A(object):
    def __init__(self, *args, **kwargs):
        print "A"
        super(A, self).__init__(*args, **kwargs)

class B(object):
    def __init__(self, *args, **kwargs):
        print "B"
        super(B, self).__init__(*args, **kwargs)

class C(A):
    def __init__(self, arg, *args, **kwargs):
        print "C","arg=",arg
        super(C, self).__init__(*args, **kwargs)

class D(B):
    def __init__(self, arg, *args, **kwargs):
        print "D", "arg=",arg
        super(D, self).__init__(*args, **kwargs)

class E(C,D):
    def __init__(self, arg, *args, **kwargs):
        print "E", "arg=",arg
        super(E, self).__init__(*args, **kwargs)

print "MRO:", [x.__name__ for x in E.__mro__]
E(10, 20, 30)

How can I get the domain name of my site within a Django template?

from django.contrib.sites.models import Site
if Site._meta.installed:
    site = Site.objects.get_current()
else:
    site = RequestSite(request)

Pass variables to AngularJS controller, best practice?

I'm not very advanced in AngularJS, but my solution would be to use a simple JS class for you cart (in the sense of coffee script) that extend Array.

The beauty of AngularJS is that you can pass you "model" object with ng-click like shown below.

I don't understand the advantage of using a factory, as I find it less pretty that a CoffeeScript class.

My solution could be transformed in a Service, for reusable purpose. But otherwise I don't see any advantage of using tools like factory or service.

class Basket extends Array
  constructor: ->

  add: (item) ->
    @push(item)

  remove: (item) ->
    index = @indexOf(item)
    @.splice(index, 1)

  contains: (item) ->
    @indexOf(item) isnt -1

  indexOf: (item) ->
    indexOf = -1
    @.forEach (stored_item, index) ->
      if (item.id is stored_item.id)
        indexOf = index
    return indexOf

Then you initialize this in your controller and create a function for that action:

 $scope.basket = new Basket()
 $scope.addItemToBasket = (item) ->
   $scope.basket.add(item)

Finally you set up a ng-click to an anchor, here you pass your object (retreived from the database as JSON object) to the function:

li ng-repeat="item in items"
  a href="#" ng-click="addItemToBasket(item)" 

How to set enum to null

An enum is a "value" type in C# (means the the enum is stored as whatever value it is, not as a reference to a place in memory where the value itself is stored). You can't set value types to null (since null is used for reference types only).

That being said you can use the built in Nullable<T> class which wraps value types such that you can set them to null, check if it HasValue and get its actual Value. (Those are both methods on the Nullable<T> objects.

name = "";
Nullable<Color> color = null; //This will work.

There is also a shortcut you can use:

Color? color = null;

That is the same as Nullable<Color>;

Eclipse cannot load SWT libraries

I came across this error when tried to start 32-bit build of Eclipse under 64-bit linux. The problem was solved after installing ia32-libs package.

How to execute an action before close metro app WinJS

If I am not mistaken, it will be onunload event.

"Occurs when the application is about to be unloaded." - MSDN

How to get hostname from IP (Linux)?

To find a hostname in your local network by IP address you can use:

nmblookup -A <ip>

To find a hostname on the internet you could use the host program:

host <ip>

Or you can install nbtscan by running:

sudo apt-get install nbtscan

And use:

nbtscan <ip>

*Taken from https://askubuntu.com/questions/205063/command-to-get-the-hostname-of-remote-server-using-ip-address/205067#205067

Update 2018-05-13

You can query a name server with nslookup. It works both ways!

nslookup <IP>
nslookup <hostname>

How can I read SMS messages from the device programmatically in Android?

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        final String myPackageName = getPackageName();
        if (!Telephony.Sms.getDefaultSmsPackage(this).equals(myPackageName)) {

            Intent intent = new Intent(Telephony.Sms.Intents.ACTION_CHANGE_DEFAULT);
            intent.putExtra(Telephony.Sms.Intents.EXTRA_PACKAGE_NAME, myPackageName);
            startActivityForResult(intent, 1);
        }else {
            List<Sms> lst = getAllSms();
        }
    }else {
        List<Sms> lst = getAllSms();
    }

Set app as default SMS app

    @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
    if (resultCode == RESULT_OK) {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            final String myPackageName = getPackageName();
            if (Telephony.Sms.getDefaultSmsPackage(mActivity).equals(myPackageName)) {

                List<Sms> lst = getAllSms();
            }
        }
    }
}
}

Function to get SMS

public List<Sms> getAllSms() {
    List<Sms> lstSms = new ArrayList<Sms>();
    Sms objSms = new Sms();
    Uri message = Uri.parse("content://sms/");
    ContentResolver cr = mActivity.getContentResolver();

    Cursor c = cr.query(message, null, null, null, null);
    mActivity.startManagingCursor(c);
    int totalSMS = c.getCount();

    if (c.moveToFirst()) {
        for (int i = 0; i < totalSMS; i++) {

            objSms = new Sms();
            objSms.setId(c.getString(c.getColumnIndexOrThrow("_id")));
            objSms.setAddress(c.getString(c
                    .getColumnIndexOrThrow("address")));
            objSms.setMsg(c.getString(c.getColumnIndexOrThrow("body")));
            objSms.setReadState(c.getString(c.getColumnIndex("read")));
            objSms.setTime(c.getString(c.getColumnIndexOrThrow("date")));
            if (c.getString(c.getColumnIndexOrThrow("type")).contains("1")) {
                objSms.setFolderName("inbox");
            } else {
                objSms.setFolderName("sent");
            }

            lstSms.add(objSms);
            c.moveToNext();
        }
    }
    // else {
    // throw new RuntimeException("You have no SMS");
    // }
    c.close();

    return lstSms;
}

Sms class is below:

public class Sms{
private String _id;
private String _address;
private String _msg;
private String _readState; //"0" for have not read sms and "1" for have read sms
private String _time;
private String _folderName;

public String getId(){
return _id;
}
public String getAddress(){
return _address;
}
public String getMsg(){
return _msg;
}
public String getReadState(){
return _readState;
}
public String getTime(){
return _time;
}
public String getFolderName(){
return _folderName;
}


public void setId(String id){
_id = id;
}
public void setAddress(String address){
_address = address;
}
public void setMsg(String msg){
_msg = msg;
}
public void setReadState(String readState){
_readState = readState;
}
public void setTime(String time){
_time = time;
}
public void setFolderName(String folderName){
_folderName = folderName;
}

}

Don't forget to define permission in your AndroidManifest.xml

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

The listener supports no services

You need to add your ORACLE_HOME definition in your listener.ora file. Right now its not registered with any ORACLE_HOME.

Sample listener.ora

abc =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = abc.kma.com)(PORT = 1521))
    )
  )

SID_LIST_abc =
  (SID_LIST =
    (SID_DESC =
      (ORACLE_HOME= /abc/DbTier/11.2.0)
      (SID_NAME = abc)
    )
  )

CONVERT Image url to Base64

HTML

<img id=imageid src=https://www.google.de/images/srpr/logo11w.png>

JavaScript

function getBase64Image(img) {
  var canvas = document.createElement("canvas");
  canvas.width = img.width;
  canvas.height = img.height;
  var ctx = canvas.getContext("2d");
  ctx.drawImage(img, 0, 0);
  var dataURL = canvas.toDataURL("image/png");
  return dataURL.replace(/^data:image\/(png|jpg);base64,/, "");
}

var base64 = getBase64Image(document.getElementById("imageid"));

This method requires the canvas element, which is perfectly supported.

The forked VM terminated without saying properly goodbye. VM crash or System.exit called

tried all above, didn't work. below solution works for me:

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.19.1</version>
<configuration>
    <argLine>-Dfile.encoding=UTF-8</argLine>
</configuration>

Which Eclipse version should I use for an Android app?

Eclipse 3.5 for Java Developer is the best option for you and 3.6 version is good but not at all because of compatibility issues.

Video format or MIME type is not supported

Firefox does not support the MPEG H.264 (mp4) format at this time, due to a philosophical disagreement with the closed-source nature of the format.

To play videos in all browsers without using plugins, you will need to host multiple copies of each video, in different formats. You will also need to use an alternate form of the video tag, as seen in the JSFiddle from @TimHayes above, reproduced below. Mozilla claims that only mp4 and WebM are necessary to ensure complete coverage of all major browsers, but you may wish to consult the Video Formats and Browser Support heading on W3C's HTML5 Video page to see which browser supports what formats.

Additionally, it's worth checking out the HTML5 Video page on Wikipedia for a basic comparison of the major file formats.

Below is the appropriate video tag (you will need to re-encode your video in WebM or OGG formats as well as your existing mp4):

<video id="video" controls='controls'>
  <source src="videos/clip.mp4" type="video/mp4"/>
  <source src="videos/clip.webm" type="video/webm"/>
  <source src="videos/clip.ogv" type="video/ogg"/>
  Your browser doesn't seem to support the video tag.
</video>

Updated Nov. 8, 2013

Network infrastructure giant Cisco has announced plans to open-source an implementation of the H.264 codec, removing the licensing fees that have so far proved a barrier to use by Mozilla. Without getting too deep into the politics of it (see following link for that) this will allow Firefox to support H.264 starting in "early 2014". However, as noted in that link, this still comes with a caveat. The H.264 codec is merely for video, and in the MPEG-4 container it is most commonly paired with the closed-source AAC audio codec. Because of this, playback of H.264 video will work, but audio will depend on whether the end-user has the AAC codec already present on their machine.

The long and short of this is that progress is being made, but you still can't avoid using multiple encodings without using a plugin.

Create a folder inside documents folder in iOS apps

I do that the following way:

NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"/MyFolder"];

if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
    [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error]; //Create folder

How to remove specific elements in a numpy array

To delete by value :

modified_array = np.delete(original_array, np.where(original_array == value_to_delete))

Releasing memory in Python

eryksun has answered question #1, and I've answered question #3 (the original #4), but now let's answer question #2:

Why does it release 50.5mb in particular - what is the amount that is released based on?

What it's based on is, ultimately, a whole series of coincidences inside Python and malloc that are very hard to predict.

First, depending on how you're measuring memory, you may only be measuring pages actually mapped into memory. In that case, any time a page gets swapped out by the pager, memory will show up as "freed", even though it hasn't been freed.

Or you may be measuring in-use pages, which may or may not count allocated-but-never-touched pages (on systems that optimistically over-allocate, like linux), pages that are allocated but tagged MADV_FREE, etc.

If you really are measuring allocated pages (which is actually not a very useful thing to do, but it seems to be what you're asking about), and pages have really been deallocated, two circumstances in which this can happen: Either you've used brk or equivalent to shrink the data segment (very rare nowadays), or you've used munmap or similar to release a mapped segment. (There's also theoretically a minor variant to the latter, in that there are ways to release part of a mapped segment—e.g., steal it with MAP_FIXED for a MADV_FREE segment that you immediately unmap.)

But most programs don't directly allocate things out of memory pages; they use a malloc-style allocator. When you call free, the allocator can only release pages to the OS if you just happen to be freeing the last live object in a mapping (or in the last N pages of the data segment). There's no way your application can reasonably predict this, or even detect that it happened in advance.

CPython makes this even more complicated—it has a custom 2-level object allocator on top of a custom memory allocator on top of malloc. (See the source comments for a more detailed explanation.) And on top of that, even at the C API level, much less Python, you don't even directly control when the top-level objects are deallocated.

So, when you release an object, how do you know whether it's going to release memory to the OS? Well, first you have to know that you've released the last reference (including any internal references you didn't know about), allowing the GC to deallocate it. (Unlike other implementations, at least CPython will deallocate an object as soon as it's allowed to.) This usually deallocates at least two things at the next level down (e.g., for a string, you're releasing the PyString object, and the string buffer).

If you do deallocate an object, to know whether this causes the next level down to deallocate a block of object storage, you have to know the internal state of the object allocator, as well as how it's implemented. (It obviously can't happen unless you're deallocating the last thing in the block, and even then, it may not happen.)

If you do deallocate a block of object storage, to know whether this causes a free call, you have to know the internal state of the PyMem allocator, as well as how it's implemented. (Again, you have to be deallocating the last in-use block within a malloced region, and even then, it may not happen.)

If you do free a malloced region, to know whether this causes an munmap or equivalent (or brk), you have to know the internal state of the malloc, as well as how it's implemented. And this one, unlike the others, is highly platform-specific. (And again, you generally have to be deallocating the last in-use malloc within an mmap segment, and even then, it may not happen.)

So, if you want to understand why it happened to release exactly 50.5mb, you're going to have to trace it from the bottom up. Why did malloc unmap 50.5mb worth of pages when you did those one or more free calls (for probably a bit more than 50.5mb)? You'd have to read your platform's malloc, and then walk the various tables and lists to see its current state. (On some platforms, it may even make use of system-level information, which is pretty much impossible to capture without making a snapshot of the system to inspect offline, but luckily this isn't usually a problem.) And then you have to do the same thing at the 3 levels above that.

So, the only useful answer to the question is "Because."

Unless you're doing resource-limited (e.g., embedded) development, you have no reason to care about these details.

And if you are doing resource-limited development, knowing these details is useless; you pretty much have to do an end-run around all those levels and specifically mmap the memory you need at the application level (possibly with one simple, well-understood, application-specific zone allocator in between).

C++ Remove new line from multiline string

Here is one for DOS or Unix new line:

    void chomp( string &s)
    {
            int pos;
            if((pos=s.find('\n')) != string::npos)
                    s.erase(pos);
    }

What is the App_Data folder used for in Visual Studio?

The App_Data folder is a folder, which your asp.net worker process has files sytem rights too, but isn't published through the web server.

For example we use it to update a local CSV of a contact us form. If the preferred method of emails fails or any querying of the data source is required, the App_Data files are there.

It's not ideal, but it it's a good fall-back.

Ajax Upload image

first in your ajax call include success & error function and then check if it gives you error or what?

your code should be like this

$(document).ready(function (e) {
    $('#imageUploadForm').on('submit',(function(e) {
        e.preventDefault();
        var formData = new FormData(this);

        $.ajax({
            type:'POST',
            url: $(this).attr('action'),
            data:formData,
            cache:false,
            contentType: false,
            processData: false,
            success:function(data){
                console.log("success");
                console.log(data);
            },
            error: function(data){
                console.log("error");
                console.log(data);
            }
        });
    }));

    $("#ImageBrowse").on("change", function() {
        $("#imageUploadForm").submit();
    });
});

How to plot a subset of a data frame in R?

This is how I would do it, in order to get in the var4 restriction:

dfr<-data.frame(var1=rnorm(100), var2=rnorm(100), var3=rnorm(100, 160, 10), var4=rnorm(100, 27, 6))
plot( subset( dfr, var3 < 155 & var4 > 27, select = c( var1, var2 ) ) )

Rgds, Rainer

How to send a stacktrace to log4j?

This answer may be not related to the question asked but related to title of the question.

public class ThrowableTest {

    public static void main(String[] args) {

        Throwable createdBy = new Throwable("Created at main()");
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        PrintWriter pw = new PrintWriter(os);
        createdBy.printStackTrace(pw);
        try {
            pw.close();
            os.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        logger.debug(os.toString());
    }
}

OR

public static String getStackTrace (Throwable t)
{
    StringWriter stringWriter = new StringWriter();
    PrintWriter  printWriter  = new PrintWriter(stringWriter);
    t.printStackTrace(printWriter);
    printWriter.close();    //surprise no IO exception here
    try {
        stringWriter.close();
    }
    catch (IOException e) {
    }
    return stringWriter.toString();
}

OR

StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
for(StackTraceElement stackTrace: stackTraceElements){
    logger.debug(stackTrace.getClassName()+ "  "+ stackTrace.getMethodName()+" "+stackTrace.getLineNumber());
}

How to get Text BOLD in Alert or Confirm box?

Maybe you coul'd use UTF8 bold chars.

For examples: https://yaytext.com/bold-italic/

It works on Chromium 80.0, I don't know on other browsers...

jQuery "blinking highlight" effect on div?

Take a look at http://jqueryui.com/demos/effect/. It has an effect named pulsate that will do exactly what you want.

$("#trigger").change(function() {$("#div_you_want_to_blink").effect("pulsate");});

How to print a Groovy variable in Jenkins?

The following code worked for me:

echo userInput

Problems with local variable scope. How to solve it?

I found this approach useful. This way you do not need a class nor final

 btnInsert.addMouseListener(new MouseAdapter() {
        private Statement _statement;

        public MouseAdapter setStatement(Statement _stmnt)
        {
            _statement = _stmnt;
            return this;
        }
        @Override
        public void mouseDown(MouseEvent e) {
            String name = text.getText();
            String from = text_1.getText();
            String to = text_2.getText();
            String price = text_3.getText();

            String query = "INSERT INTO booking (name, fromst, tost, price) VALUES ('"+name+"', '"+from+"', '"+to+"', '"+price+"')";
            try {
                _statement.executeUpdate(query);
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }
    }.setStatement(statement));

Python class input argument

Python Classes

class name:
    def __init__(self, name):
        self.name = name
        print("name: "+name)

Somewhere else:

john = name("john")

Output:
name: john

c# datagridview doubleclick on row with FullRowSelect

You get the index number of the row in the datagridview using northwind database employees tables as an example:

using System;
using System.Windows.Forms;

namespace WindowsFormsApplication5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // TODO: This line of code loads data into the 'nORTHWNDDataSet.Employees' table. You can move, or remove it, as needed.
            this.employeesTableAdapter.Fill(this.nORTHWNDDataSet.Employees);

        }

        private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
            var dataIndexNo = dataGridView1.Rows[e.RowIndex].Index.ToString();
            string cellValue = dataGridView1.Rows[e.RowIndex].Cells[1].Value.ToString();

            MessageBox.Show("The row index = " + dataIndexNo.ToString() + " and the row data in second column is: "
                + cellValue.ToString());
        }
    }
}

the result will show you index number of record and the contents of the second table column in datagridview:

enter image description here

make: Nothing to be done for `all'

Make is behaving correctly. hello already exists and is not older than the .c files, and therefore there is no more work to be done. There are four scenarios in which make will need to (re)build:

  • If you modify one of your .c files, then it will be newer than hello, and then it will have to rebuild when you run make.
  • If you delete hello, then it will obviously have to rebuild it
  • You can force make to rebuild everything with the -B option. make -B all
  • make clean all will delete hello and require a rebuild. (I suggest you look at @Mat's comment about rm -f *.o hello

AVD Manager - Cannot Create Android Virtual Device

I had trouble creating an AVD.

Either:

  • re-start eclipse after installing SDK versions from the SDK manager, or
  • you should run the "AVD Manager.exe" outside of Eclipse

Initializing multiple variables to the same value in Java

You can declare multiple variables, and initialize multiple variables, but not both at the same time:

 String one,two,three;
 one = two = three = "";

However, this kind of thing (especially the multiple assignments) would be frowned upon by most Java developers, who would consider it the opposite of "visually simple".

Call JavaScript function from C#

If you want to call JavaScript function in C#, this will help you:

public string functionname(arg)
{
    if (condition)
    {
        Page page = HttpContext.Current.CurrentHandler as Page;
        page.ClientScript.RegisterStartupScript(
            typeof(Page),
            "Test",
            "<script type='text/javascript'>functionname1(" + arg1 + ",'" + arg2 + "');</script>");
    }
}

How can I rotate an HTML <div> 90 degrees?

Use the css "rotate()" method:

_x000D_
_x000D_
div {
  width: 100px;
  height: 100px;
  background-color: yellow;
  border: 1px solid black;
}

div#rotate{
  transform: rotate(90deg);
}
_x000D_
<div>
normal div
</div>
<br>

<div id="rotate">
This div is rotated 90 degrees
</div>
_x000D_
_x000D_
_x000D_

No more data to read from socket error

We were facing same problem, we resolved it by increasing initialSize and maxActive size of connection pool.

You can check this link

Maybe this helps someone.

Use jQuery to change value of a label

Validation (HTML5): Attribute 'name' is not a valid attribute of element 'label'.

java.security.AccessControlException: Access denied (java.io.FilePermission

Just document it here on Windows you need to escape the \ character:

"e:\\directory\\-"

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

It sounds like it's just a compiler warning.

Usage of scanf_s prevents possible buffer overflow.
See: http://code.wikia.com/wiki/Scanf_s

Good explanation as to why scanf can be dangerous: Disadvantages of scanf

So as suggested, you can try replacing scanf with scanf_s or disable the compiler warning.

Create a list from two object lists with linq

Why you don't just use Concat?

Concat is a part of linq and more efficient than doing an AddRange()

in your case:

List<Person> list1 = ...
List<Person> list2 = ...
List<Person> total = list1.Concat(list2);

python 2 instead of python 3 as the (temporary) default python?

You could use alias python="/usr/bin/python2.7":

bash-3.2$ alias
bash-3.2$ python
Python 2.7.6 (v2.7.6:3a1db0d2747e, Nov 10 2013, 00:42:54) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> ^D
bash-3.2$ alias python="/usr/bin/python3.3"
bash-3.2$ python
Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 16 2013, 23:39:35) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 

Build an iOS app without owning a mac?

You can use Smartface for developing your app with javascript and deploy to stores directly without a Mac. What they say is below.

With the Cloud Build module, Smartface removes all the hassle of application deployment. You don’t need to worry about managing code signing certificates and having a Mac to sign your apps. Smartface Cloud can store all your iOS certificates and Android keystores in one place and signing and building is fully in the cloud. No matter which operating system you use, you can get store-ready (or enterprise distribution) binaries. Smartface frees you from the lock-in to Mac and allows you to use your favorite operating system for development.

https://www.smartface.io/smartface/

How to find the privileges and roles granted to a user in Oracle?

Look at http://docs.oracle.com/cd/B10501_01/server.920/a96521/privs.htm#15665

Check USER_SYS_PRIVS, USER_TAB_PRIVS, USER_ROLE_PRIVS tables with these select statements

SELECT * FROM USER_SYS_PRIVS; 
SELECT * FROM USER_TAB_PRIVS; 
SELECT * FROM USER_ROLE_PRIVS;