Programs & Examples On #Mdt

Microsoft Deployment Toolkit (MDT) is a toolset used to deploy Microsoft Windows and Office automatically in large network environments.

Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

Even without looking at assembly, the most obvious reason is that /= 2 is probably optimized as >>=1 and many processors have a very quick shift operation. But even if a processor doesn't have a shift operation, the integer division is faster than floating point division.

Edit: your milage may vary on the "integer division is faster than floating point division" statement above. The comments below reveal that the modern processors have prioritized optimizing fp division over integer division. So if someone were looking for the most likely reason for the speedup which this thread's question asks about, then compiler optimizing /=2 as >>=1 would be the best 1st place to look.


On an unrelated note, if n is odd, the expression n*3+1 will always be even. So there is no need to check. You can change that branch to

{
   n = (n*3+1) >> 1;
   count += 2;
}

So the whole statement would then be

if (n & 1)
{
    n = (n*3 + 1) >> 1;
    count += 2;
}
else
{
    n >>= 1;
    ++count;
}

Use component from another module

Note that in order to create a so called "feature module", you need to import CommonModule inside it. So, your module initialization code will look like this:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';

import { TaskCardComponent } from './task-card/task-card.component';
import { MdCardModule } from '@angular2-material/card';

@NgModule({
  imports: [
    CommonModule,
    MdCardModule 
  ],
  declarations: [
    TaskCardComponent
  ],
  exports: [
    TaskCardComponent
  ]
})
export class TaskModule { }

More information available here: https://angular.io/guide/ngmodule#create-the-feature-module

Ansible date variable

The lookup module of ansible works fine for me. The yml is:

- hosts: test
  vars:
    time: "{{ lookup('pipe', 'date -d \"1 day ago\" +\"%Y%m%d\"') }}"

You can replace any command with date to get result of the command.

Saving binary data as file using JavaScript from a browser

Use FileSaver.js. It supports Chrome, Edge, Firefox, and IE 10+ (and probably IE < 10 with a few "polyfills" - see Note 4). FileSaver.js implements the saveAs() FileSaver interface in browsers that do not natively support it:
     https://github.com/eligrey/FileSaver.js

Minified version is really small at < 2.5KB, gzipped < 1.2KB.

Usage:

/* TODO: replace the blob content with your byte[] */
var blob = new Blob([yourBinaryDataAsAnArrayOrAsAString], {type: "application/octet-stream"});
var fileName = "myFileName.myExtension";
saveAs(blob, fileName);

You might need Blob.js in some browsers (see Note 3). Blob.js implements the W3C Blob interface in browsers that do not natively support it. It is a cross-browser implementation:
     https://github.com/eligrey/Blob.js

Consider StreamSaver.js if you have files larger than blob's size limitations.

Complete example:

_x000D_
_x000D_
/* Two options_x000D_
 * 1. Get FileSaver.js from here_x000D_
 *     https://github.com/eligrey/FileSaver.js/blob/master/FileSaver.min.js -->_x000D_
 *     <script src="FileSaver.min.js" />_x000D_
 *_x000D_
 * Or_x000D_
 *_x000D_
 * 2. If you want to support only modern browsers like Chrome, Edge, Firefox, etc., _x000D_
 *    then a simple implementation of saveAs function can be:_x000D_
 */_x000D_
function saveAs(blob, fileName) {_x000D_
    var url = window.URL.createObjectURL(blob);_x000D_
_x000D_
    var anchorElem = document.createElement("a");_x000D_
    anchorElem.style = "display: none";_x000D_
    anchorElem.href = url;_x000D_
    anchorElem.download = fileName;_x000D_
_x000D_
    document.body.appendChild(anchorElem);_x000D_
    anchorElem.click();_x000D_
_x000D_
    document.body.removeChild(anchorElem);_x000D_
_x000D_
    // On Edge, revokeObjectURL should be called only after_x000D_
    // a.click() has completed, atleast on EdgeHTML 15.15048_x000D_
    setTimeout(function() {_x000D_
        window.URL.revokeObjectURL(url);_x000D_
    }, 1000);_x000D_
}_x000D_
_x000D_
(function() {_x000D_
    // convert base64 string to byte array_x000D_
    var byteCharacters = atob("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");_x000D_
    var byteNumbers = new Array(byteCharacters.length);_x000D_
    for (var i = 0; i < byteCharacters.length; i++) {_x000D_
        byteNumbers[i] = byteCharacters.charCodeAt(i);_x000D_
    }_x000D_
    var byteArray = new Uint8Array(byteNumbers);_x000D_
    _x000D_
    // now that we have the byte array, construct the blob from it_x000D_
    var blob1 = new Blob([byteArray], {type: "application/octet-stream"});_x000D_
_x000D_
    var fileName1 = "cool.gif";_x000D_
    saveAs(blob1, fileName1);_x000D_
_x000D_
    // saving text file_x000D_
    var blob2 = new Blob(["cool"], {type: "text/plain"});_x000D_
    var fileName2 = "cool.txt";_x000D_
    saveAs(blob2, fileName2);_x000D_
})();
_x000D_
_x000D_
_x000D_


Tested on Chrome, Edge, Firefox, and IE 11 (use FileSaver.js for supporting IE 11).
You can also save from a canvas element. See https://github.com/eligrey/FileSaver.js#saving-a-canvas.

Demos: https://eligrey.com/demos/FileSaver.js/

Blog post by author of FileSaver.js: http://eligrey.com/blog/post/saving-generated-files-on-the-client-side

Note 1: Browser support: https://github.com/eligrey/FileSaver.js#supported-browsers

Note 2: Failed to execute 'atob' on 'Window'

Note 3: Polyfill for browsers not supporting Blob: https://github.com/eligrey/Blob.js
                See http://caniuse.com/#search=blob

Note 4: IE < 10 support (I've not tested this part):
                https://github.com/eligrey/FileSaver.js#ie--10
                https://github.com/eligrey/FileSaver.js/issues/56#issuecomment-30917476

Downloadify is a Flash-based polyfill for supporting IE6-9: https://github.com/dcneiner/downloadify (I don't recommend Flash-based solutions in general, though.)
Demo using Downloadify and FileSaver.js for supporting IE6-9 also: http://sheetjs.com/demos/table.html

Note 5: Creating a BLOB from a Base64 string in JavaScript

Note 6: FileSaver.js examples: https://github.com/eligrey/FileSaver.js#examples

Why does my Spring Boot App always shutdown immediately after starting?

Just another possibility,

I replaced

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>

with

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

and it started without any issues

Date in to UTC format Java

Try to format your date with the Z or z timezone flags:

new SimpleDateFormat("MM/dd/yyyy KK:mm:ss a Z").format(dateObj);

Moment.js transform to date object

To convert any date, for example utc:

moment( moment().utc().format( "YYYY-MM-DD HH:mm:ss" )).toDate()

How to Solve Max Connection Pool Error

Check against any long running queries in your database.

Increasing your pool size will only make your webapp live a little longer (and probably get a lot slower)

You can use sql server profiler and filter on duration / reads to see which querys need optimization.

I also see you're probably keeping a global connection?

blnMainConnectionIsCreatedLocal

Let .net do the pooling for you and open / close your connection with a using statement.

Suggestions:

  1. Always open and close a connection like this, so .net can manage your connections and you won't run out of connections:

        using (SqlConnection conn = new SqlConnection(connectionString))
        {
         conn.Open();
         // do some stuff
        } //conn disposed
    
  2. As I mentioned, check your query with sql server profiler and see if you can optimize it. Having a slow query with many requests in a web app can give these timeouts too.

Mockito: InvalidUseOfMatchersException

For my case, the exception was raised because I tried to mock a package-access method. When I changed the method access level from package to protected the exception went away. E.g. inside below Java class,

public class Foo {
    String getName(String id) {
        return mMap.get(id);
    }
}

the method String getName(String id) has to be AT LEAST protected level so that the mocking mechanism (sub-classing) can work.

InvalidKeyException : Illegal Key Size - Java code throwing exception for encryption class - how to fix?

The error seems to be thrown when you try and load they keystore from "C:/jakarta-tomcat/webapps/PlanB/Certs/my_pkcs12.p12" here:

ks.load( new FileInputStream(_privateKeyPath), _keyPass.toCharArray() ); 

Have you tried replaceing "/" with "\\" in your file path? If that doesn't help it probably has to do with Java's Unlimited Strength Jurisdiction Policy Files. You could check this by writing a little program that does AES encryption. Try encrypting with a 128 bit key, then if that works, try with a 256 bit key and see if it fails.

Code that does AES encyrption:

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class Test 
{
    final String ALGORITHM = "AES";                       //symmetric algorithm for data encryption
    final String PADDING_MODE = "/CBC/PKCS5Padding";      //Padding for symmetric algorithm
    final String CHAR_ENCODING = "UTF-8";                 //character encoding
    //final String CRYPTO_PROVIDER = "SunMSCAPI";             //provider for the crypto

    int AES_KEY_SIZE = 256;  //symmetric key size (128, 192, 256) if using 256 you must have the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files  installed

    private String doCrypto(String plainText) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException, UnsupportedEncodingException
    {
        byte[] dataToEncrypt = plainText.getBytes(CHAR_ENCODING);

        //get the symmetric key generator
        KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);
        keyGen.init(AES_KEY_SIZE); //set the key size

        //generate the key
        SecretKey skey = keyGen.generateKey();

        //convert to binary
        byte[] rawAesKey = skey.getEncoded();

        //initialize the secret key with the appropriate algorithm
        SecretKeySpec skeySpec = new SecretKeySpec(rawAesKey, ALGORITHM);

        //get an instance of the symmetric cipher
        Cipher aesCipher = Cipher.getInstance(ALGORITHM + PADDING_MODE);

        //set it to encrypt mode, with the generated key
        aesCipher.init(Cipher.ENCRYPT_MODE, skeySpec);

        //get the initialization vector being used (to be returned)
        byte[] aesIV = aesCipher.getIV();

        //encrypt the data
        byte[] encryptedData = aesCipher.doFinal(dataToEncrypt);    

        //initialize the secret key with the appropriate algorithm
        SecretKeySpec skeySpecDec = new SecretKeySpec(rawAesKey, ALGORITHM);

        //get an instance of the symmetric cipher
        Cipher aesCipherDec = Cipher.getInstance(ALGORITHM +PADDING_MODE);

        //set it to decrypt mode with the AES key, and IV
        aesCipherDec.init(Cipher.DECRYPT_MODE, skeySpecDec, new IvParameterSpec(aesIV));

        //decrypt and return the data
        byte[] decryptedData = aesCipherDec.doFinal(encryptedData);

        return new String(decryptedData, CHAR_ENCODING);
    }

    public static void main(String[] args)
    {
        String text = "Lets encrypt me";

        Test test = new Test();

        try {
            System.out.println(test.doCrypto(text));
        } catch (InvalidKeyException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchProviderException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (BadPaddingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Does this code work for you?

You might also want to try specifying your bouncy castle provider in this line:

Cipher.getInstance(ALGORITHM +PADDING_MODE, "YOUR PROVIDER");

And see if it could be an error associated with bouncy castle.

org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1

In the Hibernate mapping file for the id property, if you use any generator class, for that property you should not set the value explicitly by using a setter method.

If you set the value of the Id property explicitly, it will lead the error above. Check this to avoid this error.

Gson and deserializing an array of objects with arrays in it

Use your bean class like this, if your JSON data starts with an an array object. it helps you.

Users[] bean = gson.fromJson(response,Users[].class);

Users is my bean class.

Response is my JSON data.

Python base64 data decode

Note Slipstream's response, that base64.b64encode and base64.b64decode need bytes-like object, not string.

>>> import base64
>>> a = '{"name": "John", "age": 42}'
>>> base64.b64encode(a)
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/lib/python3.6/base64.py", line 58, in b64encode
    encoded = binascii.b2a_base64(s, newline=False)
TypeError: a bytes-like object is required, not 'str'

How should I multiple insert multiple records?

static void InsertSettings(IEnumerable<Entry> settings) {
    using (SqlConnection oConnection = new SqlConnection("Data Source=(local);Initial Catalog=Wip;Integrated Security=True")) {
        oConnection.Open();
        using (SqlTransaction oTransaction = oConnection.BeginTransaction()) {
            using (SqlCommand oCommand = oConnection.CreateCommand()) {
                oCommand.Transaction = oTransaction;
                oCommand.CommandType = CommandType.Text;
                oCommand.CommandText = "INSERT INTO [Setting] ([Key], [Value]) VALUES (@key, @value);";
                oCommand.Parameters.Add(new SqlParameter("@key", SqlDbType.NChar));
                oCommand.Parameters.Add(new SqlParameter("@value", SqlDbType.NChar));
                try {
                    foreach (var oSetting in settings) {
                        oCommand.Parameters[0].Value = oSetting.Key;
                        oCommand.Parameters[1].Value = oSetting.Value;
                        if (oCommand.ExecuteNonQuery() != 1) {
                            //'handled as needed, 
                            //' but this snippet will throw an exception to force a rollback
                            throw new InvalidProgramException();
                        }
                    }
                    oTransaction.Commit();
                } catch (Exception) {
                    oTransaction.Rollback();
                    throw;
                }
            }
        }
    }
}

Linker error: "linker input file unused because linking not done", undefined reference to a function in that file

I think you are confused about how the compiler puts things together. When you use -c flag, i.e. no linking is done, the input is C++ code, and the output is object code. The .o files thus don't mix with -c, and compiler warns you about that. Symbols from object file are not moved to other object files like that.

All object files should be on the final linker invocation, which is not the case here, so linker (called via g++ front-end) complains about missing symbols.

Here's a small example (calling g++ explicitly for clarity):

PROG ?= myprog
OBJS = worker.o main.o

all: $(PROG)

.cpp.o:
        g++ -Wall -pedantic -ggdb -O2 -c -o $@ $<

$(PROG): $(OBJS)
        g++ -Wall -pedantic -ggdb -O2 -o $@ $(OBJS)

There's also makedepend utility that comes with X11 - helps a lot with source code dependencies. You might also want to look at the -M gcc option for building make rules.

Accessing SQL Database in Excel-VBA

Is that a proper connection string?
Where is the SQL Server instance located?

You will need to verify that you are able to conenct to SQL Server using the connection string, you specified above.

EDIT: Look at the State property of the recordset to see if it is Open?
Also, change the CursorLocation property to adUseClient before opening the recordset.

Append an object to a list in R in amortized constant time, O(1)?

This is a very interesting question and I hope my thought below could contribute an way of solution to it. This method do give a flat list without indexing, but it does have list and unlist to avoid the nesting structures. I'm not sure about the speed since I don't know how to benchmark it.

a_list<-list()
for(i in 1:3){
  a_list<-list(unlist(list(unlist(a_list,recursive = FALSE),list(rnorm(2))),recursive = FALSE))
}
a_list

[[1]]
[[1]][[1]]
[1] -0.8098202  1.1035517

[[1]][[2]]
[1] 0.6804520 0.4664394

[[1]][[3]]
[1] 0.15592354 0.07424637

How can I tell if a Java integer is null?

parseInt() is just going to throw an exception if the parsing can't complete successfully. You can instead use Integers, the corresponding object type, which makes things a little bit cleaner. So you probably want something closer to:

Integer s = null;

try { 
  s = Integer.valueOf(startField.getText());
}
catch (NumberFormatException e) {
  // ...
}

if (s != null) { ... }

Beware if you do decide to use parseInt()! parseInt() doesn't support good internationalization, so you have to jump through even more hoops:

try {
    NumberFormat nf = NumberFormat.getIntegerInstance(locale);
    nf.setParseIntegerOnly(true);
    nf.setMaximumIntegerDigits(9); // Or whatever you'd like to max out at.

    // Start parsing from the beginning.
    ParsePosition p = new ParsePosition(0);

    int val = format.parse(str, p).intValue();
    if (p.getIndex() != str.length()) {
        // There's some stuff after all the digits are done being processed.
    }

    // Work with the processed value here.
} catch (java.text.ParseFormatException exc) {
    // Something blew up in the parsing.
}

Is there any method to get the URL without query string?

Read about Window.location and the Location interface:

var url = [location.protocol, '//', location.host, location.pathname].join('');

How to commit a change with both "message" and "description" from the command line?

There is also another straight and more clear way

git commit -m "Title" -m "Description ..........";

How to check if a table exists in a given schema

Perhaps use information_schema:

SELECT EXISTS(
    SELECT * 
    FROM information_schema.tables 
    WHERE 
      table_schema = 'company3' AND 
      table_name = 'tableincompany3schema'
);

How to escape single quotes within single quoted strings

Obviously, it would be easier simply to surround with double quotes, but where's the challenge in that? Here is the answer using only single quotes. I'm using a variable instead of alias so that's it's easier to print for proof, but it's the same as using alias.

$ rxvt='urxvt -fg '\''#111111'\'' -bg '\''#111111'\'
$ echo $rxvt
urxvt -fg '#111111' -bg '#111111'

Explanation

The key is that you can close the single quote and re-open it as many times as you want. For example foo='a''b' is the same as foo='ab'. So you can close the single quote, throw in a literal single quote \', then reopen the next single quote.

Breakdown diagram

This diagram makes it clear by using brackets to show where the single quotes are opened and closed. Quotes are not "nested" like parentheses can be. You can also pay attention to the color highlighting, which is correctly applied. The quoted strings are maroon, whereas the \' is black.

'urxvt -fg '\''#111111'\'' -bg '\''#111111'\'    # original
[^^^^^^^^^^] ^[^^^^^^^] ^[^^^^^] ^[^^^^^^^] ^    # show open/close quotes
 urxvt -fg   ' #111111  '  -bg   ' #111111  '    # literal characters remaining

(This is essentially the same answer as Adrian's, but I feel this explains it better. Also his answer has 2 superfluous single quotes at the end.)

StringIO in Python3

try this

from StringIO import StringIO

x="1 3\n 4.5 8"

numpy.genfromtxt(StringIO(x))

java.lang.NoClassDefFoundError in junit

These steps worked for me when the error showed that the Filter class was missing (as reported in this false-diplicated question: JUnit: NoClassDefFoundError: org/junit/runner/manipulation/Filter ):

  1. Make sure to have JUnit 4 referenced only once in your project (I also removed the Maven nature, but I am not sure if this step has any influence in solving the problem).
  2. Right click the file containing unit tests, select Properties, and under the Run/Debug settings, remove any entries from the Launch Configurations for that file. Hit Apply and close.
  3. Right click the project containing unit tests, select Properties, and under the Run/Debug settings, remove any entries involving JUnit from the Launch Configurations. Hit Apply and close.
  4. Clean the project, and run the test.

Thanks to these answers for giving me the hint for this solution: https://stackoverflow.com/a/34067333/5538923 and https://stackoverflow.com/a/39987979/5538923).

PowerShell to remove text from a string

$a="some text =keep this,but not this"
$a.split('=')[1].split(',')[0]

returns

keep this

Efficiently checking if arbitrary object is NaN in Python / numpy / pandas?

Is your type really arbitrary? If you know it is just going to be a int float or string you could just do

 if val.dtype == float and np.isnan(val):

assuming it is wrapped in numpy , it will always have a dtype and only float and complex can be NaN

Implement division with bit-wise operator

Since bit wise operations work on bits that are either 0 or 1, each bit represents a power of 2, so if I have the bits

1010

that value is 10.

Each bit is a power of two, so if we shift the bits to the right, we divide by 2

1010 --> 0101

0101 is 5

so, in general if you want to divide by some power of 2, you need to shift right by the exponent you raise two to, to get that value

so for instance, to divide by 16, you would shift by 4, as 2^^4 = 16.

How to check if a double is null?

Firstly, a Java double cannot be null, and cannot be compared with a Java null. (The double type is a primitive (non-reference) type and primitive types cannot be null.)

Next, if you call ResultSet.getDouble(...), that returns a double not a Double, the documented behaviour is that a NULL (from the database) will be returned as zero. (See javadoc linked above.) That is no help if zero is a legitimate value for that column.

So your options are:

The getObject method will deliver the value as a Double (assuming that the column type is double), and is documented to return null for a NULL. (For more information, this page documents the default mappings of SQL types to Java types, and therefore what actual type you should expect getObject to deliver.)

Excel to JSON javascript code?

@Kwang-Chun Kang Thanks Kang a lot! I found the solution is working and very helpful, it really save my day. For me I am trying to create a React.js component that convert *.xlsx to json object when user upload the excel file to a html input tag. First I need to install XLSX package with:

npm install xlsx --save

Then in my component code, import with:

import XLSX from 'xlsx'

The component UI should look like this:

<input
  accept=".xlsx"
  type="file"
  onChange={this.fileReader}
/>

It calls a function fileReader(), which is exactly same as the solution provided. To learn more about fileReader API, I found this blog to be helpful: https://blog.teamtreehouse.com/reading-files-using-the-html5-filereader-api

JOIN queries vs multiple queries

Will it be faster in terms of throughput? Probably. But it also potentially locks more database objects at a time (depending on your database and your schema) and thereby decreases concurrency. In my experience people are often mislead by the "fewer database round-trips" argument when in reality on most OLTP systems where the database is on the same LAN, the real bottleneck is rarely the network.

How to install VS2015 Community Edition offline

You can download visual studio community edition with /layout switch.

But I prefer to use /layout with /NoRefresh for my low-speed internet connection that downloading long more than a day.

vs_community.exe /layout /NoRefresh

Every time that you run the installer it searches for new updates and if it finds updates, start downloading them and consume more time and more bandwidth!

Strip Leading and Trailing Spaces From Java String

You can try the trim() method.

String newString = oldString.trim();

Take a look at javadocs

window.open target _self v window.location.href?

You can omit window and just use location.href. For example:

location.href = 'http://google.im/';

How do I read a file line by line in VB Script?

When in doubt, read the documentation:

filename = "C:\Temp\vblist.txt"

Set fso = CreateObject("Scripting.FileSystemObject")
Set f = fso.OpenTextFile(filename)

Do Until f.AtEndOfStream
  WScript.Echo f.ReadLine
Loop

f.Close

Locate current file in IntelliJ

In addition to the other options, in at least IntelliJ IDEA 2017 Ultimate, WebStorm 2020.2, and probably a ton of other versions, you can do it in a single shortcut.

Edit preferences, search for Select in Project View, and under Keymap, view the mapped shortcut or map one of your choice.

On the Mac, Ctrl + Option + L is not already used, and is the same shortcut as Visual Studio for Windows uses natively (Ctrl + Alt + L, so that could be a good choice.

What does .class mean in Java?

When you write .class after a class name, it references the class literal - java.lang.Class object that represents information about given class.

For example, if your class is Print, then Print.class is an object that represents the class Print on runtime. It is the same object that is returned by the getClass() method of any (direct) instance of Print.

Print myPrint = new Print();
System.out.println(Print.class.getName());
System.out.println(myPrint.getClass().getName());

Codeigniter's `where` and `or_where`

$this->db->where('(a = 1 or a = 2)');

How to create range in Swift?

You can use like this

let nsRange = NSRange(location: someInt, length: someInt)

as in

let myNSString = bigTOTPCode as NSString //12345678
let firstDigit = myNSString.substringWithRange(NSRange(location: 0, length: 1)) //1
let secondDigit = myNSString.substringWithRange(NSRange(location: 1, length: 1)) //2
let thirdDigit = myNSString.substringWithRange(NSRange(location: 2, length: 4)) //3456

How to create NSIndexPath for TableView

indexPathForRow is a class method!

The code should read:

NSIndexPath *myIP = [NSIndexPath indexPathForRow:0 inSection:0] ;

Split Strings into words with multiple word boundary delimiters

Another way, without regex

import string
punc = string.punctuation
thestring = "Hey, you - what are you doing here!?"
s = list(thestring)
''.join([o for o in s if not o in punc]).split()

Calculating how many days are between two dates in DB2?

Wouldn't it just be:

SELECT CURRENT_DATE - CHDLM FROM CHCART00 WHERE CHSTAT = '05';

That should return the number of days between the two dates, if I understand how date arithmetic works in DB2 correctly.

If CHDLM isn't a date you'll have to convert it to one. According to IBM the DATE() function would not be sufficient for the yyyymmdd format, but it would work if you can format like this: yyyy-mm-dd.

How to call a PHP function on the click of a button

To show $message in your input:

<?php
    if(isset($_POST['insert'])){
        $message= "The insert function is called.";
    }
    if(isset($_POST['select'])){
        $message="The select function is called.";
    }
?>


<form  method="post">
    <input type="text" name="txt" value="<?php if(isset($message)){ echo $message;}?>" >
    <input type="submit" name="insert" value="insert">
    <input type="submit" name="select" value="select" >
</form>

To use functioncalling.php as an external file you have to include it somehow in your HTML document.

How to get an object's methods?

Get the Method Names:

var getMethodNames = function (obj) {
    return (Object.getOwnPropertyNames(obj).filter(function (key) {
        return obj[key] && (typeof obj[key] === "function");
    }));
};

Or, Get the Methods:

var getMethods     = function (obj) {
    return (Object.getOwnPropertyNames(obj).filter(function (key) {
        return obj[key] && (typeof obj[key] === "function");
    })).map(function (key) {
        return obj[key];
    });
};

Adding/removing items from a JavaScript object with jQuery

Well, it's just a javascript object, so you can manipulate data.items just like you would an ordinary array. If you do:

data.items.pop();

your items array will be 1 item shorter.

Is Java's assertEquals method reliable?

You should always use .equals() when comparing Strings in Java.

JUnit calls the .equals() method to determine equality in the method assertEquals(Object o1, Object o2).

So, you are definitely safe using assertEquals(string1, string2). (Because Strings are Objects)

Here is a link to a great Stackoverflow question regarding some of the differences between == and .equals().

Using wget to recursively fetch a directory with arbitrary files in it

The following option seems to be the perfect combination when dealing with recursive download:

wget -nd -np -P /dest/dir --recursive http://url/dir1/dir2

Relevant snippets from man pages for convenience:

   -nd
   --no-directories
       Do not create a hierarchy of directories when retrieving recursively.  With this option turned on, all files will get saved to the current directory, without clobbering (if a name shows up more than once, the
       filenames will get extensions .n).


   -np
   --no-parent
       Do not ever ascend to the parent directory when retrieving recursively.  This is a useful option, since it guarantees that only the files below a certain hierarchy will be downloaded.

How to make sql-mode="NO_ENGINE_SUBSTITUTION" permanent in MySQL my.cnf

Just to add my configuration to the mix, I'm using MySQL 5.7.8 which has the same strict sql_mode rules by default.

  • I finally figured the following working in my /etc/mysql/my.conf:

    [mysqld]
    sql-mode="STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION"
    

i.e. dash, not underscore and quotes around the value.

  • I have NO other my.conf files other than /etc/mysql/my.conf

  • There are some extra config includes being loaded from /etc/mysql/conf.d/ but they are blank.

And that seems to work for me.

Download a specific tag with Git

first fetch all the tags in that specific remote

git fetch <remote> 'refs/tags/*:refs/tags/*'

or just simply type

git fetch <remote>

Then check for the available tags

git tag -l

then switch to that specific tag using below command

git checkout tags/<tag_name>

Hope this will helps you!

How to save S3 object to a file using boto3

There is a customization that went into Boto3 recently which helps with this (among other things). It is currently exposed on the low-level S3 client, and can be used like this:

s3_client = boto3.client('s3')
open('hello.txt').write('Hello, world!')

# Upload the file to S3
s3_client.upload_file('hello.txt', 'MyBucket', 'hello-remote.txt')

# Download the file from S3
s3_client.download_file('MyBucket', 'hello-remote.txt', 'hello2.txt')
print(open('hello2.txt').read())

These functions will automatically handle reading/writing files as well as doing multipart uploads in parallel for large files.

Note that s3_client.download_file won't create a directory. It can be created as pathlib.Path('/path/to/file.txt').parent.mkdir(parents=True, exist_ok=True).

Check synchronously if file/directory exists in Node.js

const fs = require('fs');

check in the function like below,

if(fs.existsSync(<path_that_need_to_be_checked>)){
  // enter the code to excecute after the folder is there.
}
else{
  // Below code to create the folder, if its not there
  fs.mkdir('<folder_name>', cb function);
}

How to specify line breaks in a multi-line flexbox layout?

I think the traditional way is flexible and fairly easy to understand:

Markup

<div class="flex-grid">
    <div class="col-4">.col-4</div>
    <div class="col-4">.col-4</div>
    <div class="col-4">.col-4</div>

    <div class="col-4">.col-4</div>
    <div class="col-4">.col-4</div>
    <div class="col-4">.col-4</div>

    <div class="col-3">.col-3</div>
    <div class="col-9">.col-9</div>

    <div class="col-6">.col-6</div>
    <div class="col-6">.col-6</div>
</div>

Create grid.css file:

.flex-grid {
  display: flex;
  flex-flow: wrap;
}

.col-1 {flex: 0 0 8.3333%}
.col-2 {flex: 0 0 16.6666%}
.col-3 {flex: 0 0 25%}
.col-4 {flex: 0 0 33.3333%}
.col-5 {flex: 0 0 41.6666%}
.col-6 {flex: 0 0 50%}
.col-7 {flex: 0 0 58.3333%}
.col-8 {flex: 0 0 66.6666%}
.col-9 {flex: 0 0 75%}
.col-10 {flex: 0 0 83.3333%}
.col-11 {flex: 0 0 91.6666%}
.col-12 {flex: 0 0 100%}

[class*="col-"] {
  margin: 0 0 10px 0;

  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

@media (max-width: 400px) {
  .flex-grid {
    display: block;
  }
}

I've created an example (jsfiddle)

Try to resize the window under 400px, it's responsive!!

Python one-line "for" expression

for item in array: array2.append (item)

Or, in this case:

array2 += array

How to store printStackTrace into a string

You have to use getStackTrace () method instead of printStackTrace(). Here is a good example:

import java.io.*;

/**
* Simple utilities to return the stack trace of an
* exception as a String.
*/
public final class StackTraceUtil {

  public static String getStackTrace(Throwable aThrowable) {
    final Writer result = new StringWriter();
    final PrintWriter printWriter = new PrintWriter(result);
    aThrowable.printStackTrace(printWriter);
    return result.toString();
  }

  /**
  * Defines a custom format for the stack trace as String.
  */
  public static String getCustomStackTrace(Throwable aThrowable) {
    //add the class name and any message passed to constructor
    final StringBuilder result = new StringBuilder( "BOO-BOO: " );
    result.append(aThrowable.toString());
    final String NEW_LINE = System.getProperty("line.separator");
    result.append(NEW_LINE);

    //add each element of the stack trace
    for (StackTraceElement element : aThrowable.getStackTrace() ){
      result.append( element );
      result.append( NEW_LINE );
    }
    return result.toString();
  }

  /** Demonstrate output.  */
  public static void main (String... aArguments){
    final Throwable throwable = new IllegalArgumentException("Blah");
    System.out.println( getStackTrace(throwable) );
    System.out.println( getCustomStackTrace(throwable) );
  }
} 

How to update primary key

You could use this recursive function for generate necessary T-SQL script.

CREATE FUNCTION dbo.Update_Delete_PrimaryKey
(
    @TableName      NVARCHAR(255),
    @ColumnName     NVARCHAR(255),
    @OldValue       NVARCHAR(MAX),
    @NewValue       NVARCHAR(MAX),
    @Del            BIT
)
RETURNS NVARCHAR 
(
    MAX
)
AS
BEGIN
    DECLARE @fks TABLE 
            (
                constraint_name NVARCHAR(255),
                table_name NVARCHAR(255),
                col NVARCHAR(255)
            );
    DECLARE @Sql                  NVARCHAR(MAX),
            @EnableConstraints     NVARCHAR(MAX);

    SET @Sql = '';
    SET @EnableConstraints = '';

    INSERT INTO @fks
      (
        constraint_name,
        table_name,
        col
      )
    SELECT oConstraint.name     constraint_name,
           oParent.name         table_name,
           oParentCol.name      col
    FROM   sys.foreign_key_columns sfkc
           --INNER JOIN sys.foreign_keys sfk
           --     ON  sfk.[object_id] = sfkc.constraint_object_id

           INNER JOIN sys.sysobjects oConstraint
                ON  sfkc.constraint_object_id = oConstraint.id
           INNER JOIN sys.sysobjects oParent
                ON  sfkc.parent_object_id = oParent.id
           INNER JOIN sys.all_columns oParentCol
                ON  sfkc.parent_object_id = oParentCol.object_id
                AND sfkc.parent_column_id = oParentCol.column_id
           INNER JOIN sys.sysobjects oReference
                ON  sfkc.referenced_object_id = oReference.id
           INNER JOIN sys.all_columns oReferenceCol
                ON  sfkc.referenced_object_id = oReferenceCol.object_id
                AND sfkc.referenced_column_id = oReferenceCol.column_id
    WHERE  oReference.name = @TableName
           AND oReferenceCol.name = @ColumnName
    --AND (@Del <> 1 OR sfk.delete_referential_action = 0)
    --AND (@Del = 1 OR sfk.update_referential_action = 0)

    IF EXISTS(
           SELECT 1
           FROM   @fks
       )
    BEGIN
        DECLARE @Constraint     NVARCHAR(255),
                @Table          NVARCHAR(255),
                @Col            NVARCHAR(255)  

        DECLARE Table_Cursor CURSOR LOCAL 
        FOR
            SELECT f.constraint_name,
                   f.table_name,
                   f.col
            FROM   @fks AS f

        OPEN Table_Cursor FETCH NEXT FROM Table_Cursor INTO @Constraint, @Table,@Col  
        WHILE (@@FETCH_STATUS = 0)
        BEGIN
            IF @Del <> 1
            BEGIN
                SET @Sql = @Sql + 'ALTER TABLE ' + @Table + ' NOCHECK CONSTRAINT ' + @Constraint + CHAR(13) + CHAR(10);
                SET @EnableConstraints = @EnableConstraints + 'ALTER TABLE ' + @Table + ' CHECK CONSTRAINT ' + @Constraint 
                    + CHAR(13) + CHAR(10);
            END

            SET @Sql = @Sql + dbo.Update_Delete_PrimaryKey(@Table, @Col, @OldValue, @NewValue, @Del);
            FETCH NEXT FROM Table_Cursor INTO @Constraint, @Table,@Col
        END

        CLOSE Table_Cursor DEALLOCATE Table_Cursor
    END

    DECLARE @DataType NVARCHAR(30);
    SELECT @DataType = t.name +
           CASE 
                WHEN t.name IN ('char', 'varchar', 'nchar', 'nvarchar') THEN '(' +
                     CASE 
                          WHEN c.max_length = -1 THEN 'MAX'
                          ELSE CONVERT(
                                   VARCHAR(4),
                                   CASE 
                                        WHEN t.name IN ('nchar', 'nvarchar') THEN c.max_length / 2
                                        ELSE c.max_length
                                   END
                               )
                     END + ')'
                WHEN t.name IN ('decimal', 'numeric') THEN '(' + CONVERT(VARCHAR(4), c.precision) + ',' 
                     + CONVERT(VARCHAR(4), c.Scale) + ')'
                ELSE ''
           END
    FROM   sys.columns c
           INNER JOIN sys.types t
                ON  c.user_type_id = t.user_type_id
    WHERE  c.object_id = OBJECT_ID(@TableName)
           AND c.name = @ColumnName

    IF @Del <> 1
    BEGIN
        SET @Sql = @Sql + 'UPDATE [' + @TableName + '] SET [' + @ColumnName + '] = CONVERT(' + @DataType + ', ' + ISNULL('N''' + @NewValue + '''', 'NULL') 
            + ') WHERE [' + @ColumnName + '] = CONVERT(' + @DataType + ', ' + ISNULL('N''' + @OldValue + '''', 'NULL') +
            ');' + CHAR(13) + CHAR(10);
        SET @Sql = @Sql + @EnableConstraints;
    END
    ELSE
        SET @Sql = @Sql + 'DELETE [' + @TableName + '] WHERE [' + @ColumnName + '] = CONVERT(' + @DataType + ', N''' + @OldValue 
            + ''');' + CHAR(13) + CHAR(10);
    RETURN @Sql;
END
GO

DECLARE @Result NVARCHAR(MAX);
SET @Result = dbo.Update_Delete_PrimaryKey('@TableName', '@ColumnName', '@OldValue', '@NewValue', 0);/*Update*/
EXEC (@Result)
SET @Result = dbo.Update_Delete_PrimaryKey('@TableName', '@ColumnName', '@OldValue', NULL, 1);/*Delete*/
EXEC (@Result)
GO

DROP FUNCTION Update_Delete_PrimaryKey;

How to iterate through a table rows and get the cell values using jQuery

You got your answer, but why iterate over the tr when you can go straight for the inputs? That way you can store them easier into an array and it reduce the number of CSS queries. Depends what you want to do of course, but for collecting data it is a more flexible approach.

http://jsfiddle.net/zqpgq/

var array = [];

$("tr.item input").each(function() {
    array.push({
        name: $(this).attr('class'),
        value: $(this).val()
    });
});

console.log(array);?

Round button with text and icon in flutter

Congrats to the previous answers... But I realised if the icons are in a row (say three icons as represented in the image above), you need to play around with columns and rows.

Here is the code

 Column(
        crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceAround,
                children: [
                  FlatButton(
                      onPressed: () {},
                      child: Icon(
                        Icons.call,
                      )),
                  FlatButton(
                      onPressed: () {},
                      child: Icon(
                        Icons.message,
                      )),
                  FlatButton(
                      onPressed: () {},
                      child: Icon(
                        Icons.block,
                        color: Colors.red,
                      )),
                ],
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceAround,
                children: <Widget>[
                  Text(
                    '   Call',
                  ),
                  Text(
                    'Message',
                  ),
                  Text(
                    'Block',
                    style: TextStyle(letterSpacing: 2.0, color: Colors.red),
                  ),
                ],
              ),
            ],
          ),

Here is the result

How to calculate md5 hash of a file using javascript

You need to to use FileAPI. It is available in the latest FF & Chrome, but not IE9. Grab any md5 JS implementation suggested above. I've tried this and abandoned it because JS was too slow (minutes on large image files). Might revisit it if someone rewrites MD5 using typed arrays.

Code would look something like this:

HTML:     
<input type="file" id="file-dialog" multiple="true" accept="image/*">

JS (w JQuery)

$("#file-dialog").change(function() {
  handleFiles(this.files);
});

function handleFiles(files) {
    for (var i=0; i<files.length; i++) {
        var reader = new FileReader();
        reader.onload = function() {
        var md5 = binl_md5(reader.result, reader.result.length);
            console.log("MD5 is " + md5);
        };
        reader.onerror = function() {
            console.error("Could not read the file");
        };
        reader.readAsBinaryString(files.item(i));
     }
 }

How to set cookie in node js using express framework?

The order in which you use middleware in Express matters: middleware declared earlier will get called first, and if it can handle a request, any middleware declared later will not get called.

If express.static is handling the request, you need to move your middleware up:

// need cookieParser middleware before we can do anything with cookies
app.use(express.cookieParser());

// set a cookie
app.use(function (req, res, next) {
  // check if client sent cookie
  var cookie = req.cookies.cookieName;
  if (cookie === undefined) {
    // no: set a new cookie
    var randomNumber=Math.random().toString();
    randomNumber=randomNumber.substring(2,randomNumber.length);
    res.cookie('cookieName',randomNumber, { maxAge: 900000, httpOnly: true });
    console.log('cookie created successfully');
  } else {
    // yes, cookie was already present 
    console.log('cookie exists', cookie);
  } 
  next(); // <-- important!
});

// let static middleware do its job
app.use(express.static(__dirname + '/public'));

Also, middleware needs to either end a request (by sending back a response), or pass the request to the next middleware. In this case, I've done the latter by calling next() when the cookie has been set.

Update

As of now the cookie parser is a seperate npm package, so instead of using

app.use(express.cookieParser());

you need to install it separately using npm i cookie-parser and then use it as:

const cookieParser = require('cookie-parser');
app.use(cookieParser());

Which mime type should I use for mp3

The standard way is to use audio/mpeg which is something like this in your PHP header function ...

header('Content-Type: audio/mpeg');

Python add item to the tuple

You need to make the second element a 1-tuple, eg:

a = ('2',)
b = 'z'
new = a + (b,)

How to apply CSS page-break to print a table with lots of rows?

You should use

<tbody> 
  <tr>
  first page content here 
  </tr>
  <tr>
  ..
  </tr>
</tbody>
<tbody>
  next page content...
</tbody>

And CSS:

tbody { display: block; page-break-before: avoid; }
tbody { display: block; page-break-after: always; }

PermGen elimination in JDK 8

Because the PermGen space was removed. Memory management has changed a bit.

java-8-permgen-metaspace

Confirm deletion using Bootstrap 3 modal box

simple way to use modals is with eModal!

Ex from github:

  1. Link to eModal.js <script src="//rawgit.com/saribe/eModal/master/dist/eModal.min.js"></script>

_x000D_
_x000D_
    var options = {_x000D_
            message: "The famouse question?",_x000D_
            title: 'Header title',_x000D_
            size: 'sm',_x000D_
            callback: function(result) { result ? doActionTrue(result) :    doActionFalse(); },_x000D_
            subtitle: 'smaller text header',_x000D_
            label: "True"   // use the possitive lable as key_x000D_
            //..._x000D_
        };_x000D_
                     _x000D_
    eModal.confirm(options);
_x000D_
 <link href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.1/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.1/js/bootstrap.min.js"></script>_x000D_
<script src="//rawgit.com/saribe/eModal/master/dist/eModal.min.js"></script>
_x000D_
_x000D_
_x000D_

Tip: You can use change the default label name! { label: 'Yes' | 'True'| 'OK' }

How to correctly catch change/focusOut event on text input in React.js?

Its late, yet it's worth your time nothing that, there are some differences in browser level implementation of focusin and focusout events and react synthetic onFocus and onBlur. focusin and focusout actually bubble, while onFocus and onBlur dont. So there is no exact same implementation for focusin and focusout as of now for react. Anyway most cases will be covered in onFocus and onBlur.

Formatting a number with leading zeros in PHP

You can always abuse type juggling:

function zpad(int $value, int $pad): string {
    return substr(1, $value + 10 ** $pad);
}

This wont work as expected if either 10 ** pad > INT_MAX or value >= 10 * pad.

Generate a heatmap in MatPlotLib using a scatter data set

Edit: For a better approximation of Alejandro's answer, see below.

I know this is an old question, but wanted to add something to Alejandro's anwser: If you want a nice smoothed image without using py-sphviewer you can instead use np.histogram2d and apply a gaussian filter (from scipy.ndimage.filters) to the heatmap:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
from scipy.ndimage.filters import gaussian_filter


def myplot(x, y, s, bins=1000):
    heatmap, xedges, yedges = np.histogram2d(x, y, bins=bins)
    heatmap = gaussian_filter(heatmap, sigma=s)

    extent = [xedges[0], xedges[-1], yedges[0], yedges[-1]]
    return heatmap.T, extent


fig, axs = plt.subplots(2, 2)

# Generate some test data
x = np.random.randn(1000)
y = np.random.randn(1000)

sigmas = [0, 16, 32, 64]

for ax, s in zip(axs.flatten(), sigmas):
    if s == 0:
        ax.plot(x, y, 'k.', markersize=5)
        ax.set_title("Scatter plot")
    else:
        img, extent = myplot(x, y, s)
        ax.imshow(img, extent=extent, origin='lower', cmap=cm.jet)
        ax.set_title("Smoothing with  $\sigma$ = %d" % s)

plt.show()

Produces:

Output images

The scatter plot and s=16 plotted on top of eachother for Agape Gal'lo (click for better view):

On top of eachother


One difference I noticed with my gaussian filter approach and Alejandro's approach was that his method shows local structures much better than mine. Therefore I implemented a simple nearest neighbour method at pixel level. This method calculates for each pixel the inverse sum of the distances of the n closest points in the data. This method is at a high resolution pretty computationally expensive and I think there's a quicker way, so let me know if you have any improvements.

Update: As I suspected, there's a much faster method using Scipy's scipy.cKDTree. See Gabriel's answer for the implementation.

Anyway, here's my code:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm


def data_coord2view_coord(p, vlen, pmin, pmax):
    dp = pmax - pmin
    dv = (p - pmin) / dp * vlen
    return dv


def nearest_neighbours(xs, ys, reso, n_neighbours):
    im = np.zeros([reso, reso])
    extent = [np.min(xs), np.max(xs), np.min(ys), np.max(ys)]

    xv = data_coord2view_coord(xs, reso, extent[0], extent[1])
    yv = data_coord2view_coord(ys, reso, extent[2], extent[3])
    for x in range(reso):
        for y in range(reso):
            xp = (xv - x)
            yp = (yv - y)

            d = np.sqrt(xp**2 + yp**2)

            im[y][x] = 1 / np.sum(d[np.argpartition(d.ravel(), n_neighbours)[:n_neighbours]])

    return im, extent


n = 1000
xs = np.random.randn(n)
ys = np.random.randn(n)
resolution = 250

fig, axes = plt.subplots(2, 2)

for ax, neighbours in zip(axes.flatten(), [0, 16, 32, 64]):
    if neighbours == 0:
        ax.plot(xs, ys, 'k.', markersize=2)
        ax.set_aspect('equal')
        ax.set_title("Scatter Plot")
    else:
        im, extent = nearest_neighbours(xs, ys, resolution, neighbours)
        ax.imshow(im, origin='lower', extent=extent, cmap=cm.jet)
        ax.set_title("Smoothing over %d neighbours" % neighbours)
        ax.set_xlim(extent[0], extent[1])
        ax.set_ylim(extent[2], extent[3])
plt.show()

Result:

Nearest Neighbour Smoothing

How do I connect to a specific Wi-Fi network in Android programmatically?

This is an activity you can subclass to force the connecting to a specific wifi: https://github.com/zoltanersek/android-wifi-activity/blob/master/app/src/main/java/com/zoltanersek/androidwifiactivity/WifiActivity.java

You will need to subclass this activity and implement its methods:

public class SampleActivity extends WifiBaseActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  }

  @Override
  protected int getSecondsTimeout() {
      return 10;
  }

  @Override
  protected String getWifiSSID() {
      return "WifiNetwork";
  }

  @Override
  protected String getWifiPass() {
      return "123456";
  }
}

How to convert a multipart file to File?

  private File convertMultiPartToFile(MultipartFile file ) throws IOException
    {
        File convFile = new File( file.getOriginalFilename() );
        FileOutputStream fos = new FileOutputStream( convFile );
        fos.write( file.getBytes() );
        fos.close();
        return convFile;
    }

How to merge 2 JSON objects from 2 files using jq?

Use jq -s add:

$ echo '{"a":"foo","b":"bar"} {"c":"baz","a":0}' | jq -s add
{
  "a": 0,
  "b": "bar",
  "c": "baz"
}

This reads all JSON texts from stdin into an array (jq -s does that) then it "reduces" them.

(add is defined as def add: reduce .[] as $x (null; . + $x);, which iterates over the input array's/object's values and adds them. Object addition == merge.)

PHP class: Global variable as property in class

class myClass { protected $foo;

public function __construct(&$var)
{
    $this->foo = &$var;
}

public function foo()
{
    return ++$this->foo;
}

}

Reducing MongoDB database file size

I had the same problem, and solved by simply doing this at the command line:

mongodump -d databasename
echo 'db.dropDatabase()' | mongo databasename
mongorestore dump/databasename

Is there a rule-of-thumb for how to divide a dataset into training and validation sets?

You'd be surprised to find out that 80/20 is quite a commonly occurring ratio, often referred to as the Pareto principle. It's usually a safe bet if you use that ratio.

However, depending on the training/validation methodology you employ, the ratio may change. For example: if you use 10-fold cross validation, then you would end up with a validation set of 10% at each fold.

There has been some research into what is the proper ratio between the training set and the validation set:

The fraction of patterns reserved for the validation set should be inversely proportional to the square root of the number of free adjustable parameters.

In their conclusion they specify a formula:

Validation set (v) to training set (t) size ratio, v/t, scales like ln(N/h-max), where N is the number of families of recognizers and h-max is the largest complexity of those families.

What they mean by complexity is:

Each family of recognizer is characterized by its complexity, which may or may not be related to the VC-dimension, the description length, the number of adjustable parameters, or other measures of complexity.

Taking the first rule of thumb (i.e.validation set should be inversely proportional to the square root of the number of free adjustable parameters), you can conclude that if you have 32 adjustable parameters, the square root of 32 is ~5.65, the fraction should be 1/5.65 or 0.177 (v/t). Roughly 17.7% should be reserved for validation and 82.3% for training.

How do you use subprocess.check_output() in Python?

The right answer (using Python 2.7 and later, since check_output() was introduced then) is:

py2output = subprocess.check_output(['python','py2.py','-i', 'test.txt'])

To demonstrate, here are my two programs:

py2.py:

import sys
print sys.argv

py3.py:

import subprocess
py2output = subprocess.check_output(['python', 'py2.py', '-i', 'test.txt'])
print('py2 said:', py2output)

Running it:

$ python3 py3.py
py2 said: b"['py2.py', '-i', 'test.txt']\n"

Here's what's wrong with each of your versions:

py2output = subprocess.check_output([str('python py2.py '),'-i', 'test.txt'])

First, str('python py2.py') is exactly the same thing as 'python py2.py'—you're taking a str, and calling str to convert it to an str. This makes the code harder to read, longer, and even slower, without adding any benefit.

More seriously, python py2.py can't be a single argument, unless you're actually trying to run a program named, say, /usr/bin/python\ py2.py. Which you're not; you're trying to run, say, /usr/bin/python with first argument py2.py. So, you need to make them separate elements in the list.

Your second version fixes that, but you're missing the ' before test.txt'. This should give you a SyntaxError, probably saying EOL while scanning string literal.

Meanwhile, I'm not sure how you found documentation but couldn't find any examples with arguments. The very first example is:

>>> subprocess.check_output(["echo", "Hello World!"])
b'Hello World!\n'

That calls the "echo" command with an additional argument, "Hello World!".

Also:

-i is a positional argument for argparse, test.txt is what the -i is

I'm pretty sure -i is not a positional argument, but an optional argument. Otherwise, the second half of the sentence makes no sense.

Rounding numbers to 2 digits after comma

UPDATE: Keep in mind, at the time the answer was initially written in 2010, the bellow function toFixed() worked slightly different. toFixed() seems to do some rounding now, but not in the strictly mathematical manner. So be careful with it. Do your tests... The method described bellow will do rounding well, as mathematician would expect.

  • toFixed() - method converts a number into a string, keeping a specified number of decimals. It does not actually rounds up a number, it truncates the number.
  • Math.round(n) - rounds a number to the nearest integer. Thus turning:

0.5 -> 1; 0.05 -> 0

so if you want to round, say number 0.55555, only to the second decimal place; you can do the following(this is step-by-step concept):

  • 0.55555 * 100 = 55.555
  • Math.Round(55.555) -> 56.000
  • 56.000 / 100 = 0.56000
  • (0.56000).toFixed(2) -> 0.56

and this is the code:

(Math.round(number * 100)/100).toFixed(2);

Regular expression to validate US phone numbers?

The easiest way to match both

^\([0-9]{3}\)[0-9]{3}-[0-9]{4}$

and

^[0-9]{3}-[0-9]{3}-[0-9]{4}$

is to use alternation ((...|...)): specify them as two mostly-separate options:

^(\([0-9]{3}\)|[0-9]{3}-)[0-9]{3}-[0-9]{4}$

By the way, when Americans put the area code in parentheses, we actually put a space after that; for example, I'd write (123) 123-1234, not (123)123-1234. So you might want to write:

^(\([0-9]{3}\) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$

(Though it's probably best to explicitly demonstrate the format that you expect phone numbers to be in.)

How to vertically align text with icon font?

In this scenario, since you are working with inline-level elements, you could add vertical-align: middle to the span elements for vertical centering:

.nav-text {
  vertical-align: middle;
}

Alternatively, you could set the display of the parent element to flex and set align-items to center for vertical centering:

.menu {
  display: flex;
  align-items: center;
}

The type or namespace name 'System' could not be found

Open Project References, I had lots of yellow warning triangles on the various packages. Click Add Reference, just doing that seems to get VS to refresh it references, and the yellow triangles disappeared and the errors from the code also.

You might have to do this in a few projects if your solution reference to other projects

Pass a javascript variable value into input type hidden value

Check out this jQuery page for some interesting examples of how to play with the value attribute, and how to call it:

http://api.jquery.com/val/

Otherwise - if you want to use jQuery rather than javascript in passing variables to an input of any kind, use the following to set the value of the input on an event click(), submit() et al:

on some event; assign or set the value of the input:

$('#inputid').val($('#idB').text());

where:

<input id = "inputid" type = "hidden" />

<div id = "idB">This text will be passed to the input</div>

Using such an approach, make sure the html input does not already specify a value, or a disabled attribute, obviously.

Beware the differences betwen .html() and .text() when dealing with html forms.

How do I check if a string contains another string in Objective-C?

try this,

NSString *string = @"test Data";
if ([[string lowercaseString] rangeOfString:@"data"].location == NSNotFound) 
{
    NSLog(@"string does not contain Data");
}   
else 
{
    NSLog(@"string contains data!");
}

Javascript : get <img> src and set as variable?

If you don't have an id on the image but have a parent div this is also a technique you can use.

<div id="myDiv"><img src="http://www.example.com/image.png"></div>

var myVar = document.querySelectorAll('#myDiv img')[0].src

How can I dismiss the on screen keyboard?

None of the above solutions don't work for me.

Flutter suggests this - Put your widget inside new GestureDetector() on which tap will hide keyboard and onTap use FocusScope.of(context).requestFocus(new FocusNode())

class Home extends StatelessWidget {
@override
  Widget build(BuildContext context) {
    var widget = new MaterialApp(
        home: new Scaffold(
            body: new Container(
                height:500.0,
                child: new GestureDetector(
                    onTap: () {
                        FocusScope.of(context).requestFocus(new FocusNode());
                    },
                    child: new Container(
                        color: Colors.white,
                        child:  new Column(
                            mainAxisAlignment:  MainAxisAlignment.center,
                            crossAxisAlignment: CrossAxisAlignment.center,

                            children: [
                                new TextField( ),
                                new Text("Test"),                                
                            ],
                        )
                    )
                )
            )
        ),
    );

    return widget;
}}

Declaring a xsl variable and assigning value to it

No, unlike in a lot of other languages, XSLT variables cannot change their values after they are created. You can however, avoid extraneous code with a technique like this:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>

  <xsl:variable name="mapping">
    <item key="1" v1="A" v2="B" />
    <item key="2" v1="X" v2="Y" />
  </xsl:variable>
  <xsl:variable name="mappingNode"
                select="document('')//xsl:variable[@name = 'mapping']" />

  <xsl:template match="....">
    <xsl:variable name="testVariable" select="'1'" />

    <xsl:variable name="values" select="$mappingNode/item[@key = $testVariable]" />

    <xsl:variable name="variable1" select="$values/@v1" />
    <xsl:variable name="variable2" select="$values/@v2" />
  </xsl:template>
</xsl:stylesheet>

In fact, once you've got the values variable, you may not even need separate variable1 and variable2 variables. You could just use $values/@v1 and $values/@v2 instead.

ORA-00054: resource busy and acquire with NOWAIT specified

Step 1:

select object_name, s.sid, s.serial#, p.spid 
from v$locked_object l, dba_objects o, v$session s, v$process p
where l.object_id = o.object_id and l.session_id = s.sid and s.paddr = p.addr;

Step 2:

alter system kill session 'sid,serial#'; --`sid` and `serial#` get from step 1

More info: http://www.oracle-base.com/articles/misc/killing-oracle-sessions.php

Combine two arrays

Just use:

$output = array_merge($array1, $array2);

That should solve it. Because you use string keys if one key occurs more than one time (like '44' in your example) one key will overwrite proceding ones with the same name. Because in your case they both have the same value anyway it doesn't matter and it will also remove duplicates.

Update: I just realised, that PHP treats the numeric string-keys as numbers (integers) and so will behave like this, what means, that it renumbers the keys too...

A workaround is to recreate the keys.

$output = array_combine($output, $output);

Update 2: I always forget, that there is also an operator (in bold, because this is really what you are looking for! :D)

$output = $array1 + $array2;

All of this can be seen in: http://php.net/manual/en/function.array-merge.php

Is it possible to open developer tools console in Chrome on Android phone?

I you only want to see what was printed in the console you could simple add the "printed" part somewhere in your HTML so it will appear in on the webpage. You could do it for yourself, but there is a javascript file that does this for you. You can read about it here:

http://www.hnldesign.nl/work/code/mobileconsole-javascript-console-for-mobile-devices/

The code is available from Github; you can download it and paste it into a javascipt file and add it in to your HTML

How can I return to a parent activity correctly?

Although an old question, here is another (imho the cleanest and best) solution as all the previous answeres didn't work for me since I deeplinked Activity B from a Widget.

public void navigateUp() {
final Intent upIntent = NavUtils.getParentActivityIntent(this);
if (NavUtils.shouldUpRecreateTask(this, upIntent) || isTaskRoot()) {
    Log.v(logTag, "Recreate back stack");
        TaskStackBuilder.create(this).addNextIntentWithParentStack(upIntent).startActivities();
  } else {
    NavUtils.navigateUpTo(this, upIntent);
  }
}

[https://stackoverflow.com/a/31350642/570168 ]

But also see: https://speakerdeck.com/jgilfelt/this-way-up-implementing-effective-navigation-on-android

How to connect HTML Divs with Lines?

Create a div that is the line with the code like this:

CSS

div#lineHorizontal {
    background-color: #000;
    width: //the width of the line or how far it goes sidewards;
    height: 2px;
    display: inline-block;
    margin: 0px;
 }
div#block {
    background-color: #777;
    display: inline-block;
    margin: 0px;
}

HTML

<div id="block">
</div>
<div id="lineHorizontal">
</div>
<div id="block">
</div>

This will display a block with a horizontal line to another block.

On mobile devices you could use (caniuse.com/transforms2d)

how to get the current working directory's absolute path from irb

File.expand_path File.dirname(__FILE__) will return the directory relative to the file this command is called from.

But Dir.pwd returns the working directory (results identical to executing pwd in your terminal)

Getting SyntaxError for print with keyword argument end=' '

It looks like you're just missing an opening double-quote. Try:

if Verbose:
   print("Building internam Index for %d tile(s) ..." % len(inputTiles), end=' ')

Calculate the display width of a string in Java

And now for something completely different. The following assumes arial font, and makes a wild guess based on a linear interpolation of character vs width.

// Returns the size in PICA of the string, given space is 200 and 'W' is 1000.
// see https://p2p.wrox.com/access/32197-calculate-character-widths.html

static int picaSize(String s)
{
    // the following characters are sorted by width in Arial font
    String lookup = " .:,;'^`!|jl/\\i-()JfIt[]?{}sr*a\"ce_gFzLxkP+0123456789<=>~qvy$SbduEphonTBCXY#VRKZN%GUAHD@OQ&wmMW";
    int result = 0;
    for (int i = 0; i < s.length(); ++i)
    {
        int c = lookup.indexOf(s.charAt(i));
        result += (c < 0 ? 60 : c) * 7 + 200;
    }
    return result;
}

Interesting, but perhaps not very practical.

QByteArray to QString

Qt 4.8

QString(byteArray).toStdString();

Qt 5.12

byteArray.toStdString();

How to implement an STL-style iterator and avoid common pitfalls?

First of all you can look here for a list of the various operations the individual iterator types need to support.

Next, when you have made your iterator class you need to either specialize std::iterator_traits for it and provide some necessary typedefs (like iterator_category or value_type) or alternatively derive it from std::iterator, which defines the needed typedefs for you and can therefore be used with the default std::iterator_traits.

disclaimer: I know some people don't like cplusplus.com that much, but they provide some really useful information on this.

How do I copy directories recursively with gulp?

Turns out that to copy a complete directory structure gulp needs to be provided with a base for your gulp.src() method.

So gulp.src( [ files ], { "base" : "." }) can be used in the structure above to copy all the directories recursively.

If, like me, you may forget this then try:

gulp.copy=function(src,dest){
    return gulp.src(src, {base:"."})
        .pipe(gulp.dest(dest));
};

Best way to create enum of strings?

You can use that for string Enum

public enum EnumTest {
    NAME_ONE("Name 1"),
    NAME_TWO("Name 2");

    private final String name;

    /**
     * @param name
     */
    private EnumTest(final String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

And call from main method

public class Test {
    public static void main (String args[]){
        System.out.println(EnumTest.NAME_ONE.getName());
        System.out.println(EnumTest.NAME_TWO.getName());
    }
}

Injection of autowired dependencies failed;

Do you have a bean declared in your context file that has an id of "articleService"? I believe that autowiring matches the id of a bean in your context files with the variable name that you are attempting to Autowire.

How can I display two div in one line via css inline property

use inline-block instead of inline. Read more information here about the difference between inline and inline-block.

.inline { 
display: inline-block; 
border: 1px solid red; 
margin:10px;
}

DEMO

Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist

In my case the path of MySQL data folder had a special character "ç" and it make me get...

Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist.

I'm have removed all special characters and everything works.

How to prevent http file caching in Apache httpd (MAMP)

<FilesMatch "\.(js|css)$">
  ExpiresActive On
  ExpiresDefault A1
  Header append Cache-Control must-revalidate
</FilesMatch>

MySQL Trigger after update only if row has changed

As a workaround, you could use the timestamp (old and new) for checking though, that one is not updated when there are no changes to the row. (Possibly that is the source for confusion? Because that one is also called 'on update' but is not executed when no change occurs) Changes within one second will then not execute that part of the trigger, but in some cases that could be fine (like when you have an application that rejects fast changes anyway.)

For example, rather than

IF NEW.a <> OLD.a or NEW.b <> OLD.b /* etc, all the way to NEW.z <> OLD.z */ 
THEN  
  INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b) ;
END IF

you could use

IF NEW.ts <> OLD.ts 
THEN  
  INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b) ;
END IF

Then you don't have to change your trigger every time you update the scheme (the issue you mentioned in the question.)

EDIT: Added full example

create table foo (a INT, b INT, ts TIMESTAMP);
create table bar (a INT, b INT);

INSERT INTO foo (a,b) VALUES(1,1);
INSERT INTO foo (a,b) VALUES(2,2);
INSERT INTO foo (a,b) VALUES(3,3);

DELIMITER ///

CREATE TRIGGER ins_sum AFTER UPDATE ON foo
    FOR EACH ROW
    BEGIN
        IF NEW.ts <> OLD.ts THEN  
            INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b);
        END IF;
    END;
///

DELIMITER ;

select * from foo;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    1 |    1 | 2011-06-14 09:29:46 |
|    2 |    2 | 2011-06-14 09:29:46 |
|    3 |    3 | 2011-06-14 09:29:46 |
+------+------+---------------------+
3 rows in set (0.00 sec)

-- UPDATE without change
UPDATE foo SET b = 3 WHERE a = 3;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

-- the timestamo didnt change
select * from foo WHERE a = 3;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    3 |    3 | 2011-06-14 09:29:46 |
+------+------+---------------------+
1 rows in set (0.00 sec)

-- the trigger didn't run
select * from bar;
Empty set (0.00 sec)

-- UPDATE with change
UPDATE foo SET b = 4 WHERE a=3;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

-- the timestamp changed
select * from foo;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    1 |    1 | 2011-06-14 09:29:46 |
|    2 |    2 | 2011-06-14 09:29:46 |
|    3 |    4 | 2011-06-14 09:34:59 |
+------+------+---------------------+
3 rows in set (0.00 sec)

-- and the trigger ran
select * from bar;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    3 |    4 | 2011-06-14 09:34:59 |
+------+------+---------------------+
1 row in set (0.00 sec)

It is working because of mysql's behavior on handling timestamps. The time stamp is only updated if a change occured in the updates.

Documentation is here:
https://dev.mysql.com/doc/refman/5.7/en/timestamp-initialization.html

desc foo;
+-------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type      | Null | Key | Default           | Extra                       |
+-------+-----------+------+-----+-------------------+-----------------------------+
| a     | int(11)   | YES  |     | NULL              |                             |
| b     | int(11)   | YES  |     | NULL              |                             |
| ts    | timestamp | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------+-----------+------+-----+-------------------+-----------------------------+

Why is the GETDATE() an invalid identifier

Use ORACLE equivalent of getdate() which is sysdate . Read about here. Getdate() belongs to SQL Server , will not work on Oracle.

Other option is current_date

How do I check whether a file exists without exceptions?

import os
#Your path here e.g. "C:\Program Files\text.txt"
#For access purposes: "C:\\Program Files\\text.txt"
if os.path.exists("C:\..."):   
    print "File found!"
else:
    print "File not found!"

Importing os makes it easier to navigate and perform standard actions with your operating system.

For reference also see How to check whether a file exists using Python?

If you need high-level operations, use shutil.

What is the native keyword in Java for?

NATIVE is Non access modifier.it can be applied only to METHOD. It indicates the PLATFORM-DEPENDENT implementation of method or code.

Can I underline text in an Android layout?

For Button and TextView this is the easiest way:

Button:

Button button = (Button) findViewById(R.id.btton1);
button.setPaintFlags(button.getPaintFlags() | Paint.UNDERLINE_TEXT_FLAG);

Textview:

TextView textView = (TextView) findViewById(R.id.textview1);
textView.setPaintFlags(textView.getPaintFlags() | Paint.UNDERLINE_TEXT_FLAG);

Zsh: Conda/Pip installs command not found

If this problem occurs on a mac, then type the following commands:

source <path to conda>/bin/activate
conda init zsh

This will modify your zshrc accordingly (or create it if it does not exist).

This solution comes from the official anaconda doc.

casting Object array to Integer array error

Ross, you can use Arrays.copyof() or Arrays.copyOfRange() too.

Integer[] integerArray = Arrays.copyOf(a, a.length, Integer[].class);
Integer[] integerArray = Arrays.copyOfRange(a, 0, a.length, Integer[].class);

Here the reason to hitting an ClassCastException is you can't treat an array of Integer as an array of Object. Integer[] is a subtype of Object[] but Object[] is not a Integer[].

And the following also will not give an ClassCastException.

Object[] a = new Integer[1];
Integer b=1;
a[0]=b;
Integer[] c = (Integer[]) a;

Difference between java.exe and javaw.exe

java.exe is the command where it waits for application to complete untill it takes the next command. javaw.exe is the command which will not wait for the application to complete. you can go ahead with another commands.

Overriding !important style

I believe the only way to do this it to add the style as a new CSS declaration with the '!important' suffix. The easiest way to do this is to append a new <style> element to the head of document:

function addNewStyle(newStyle) {
    var styleElement = document.getElementById('styles_js');
    if (!styleElement) {
        styleElement = document.createElement('style');
        styleElement.type = 'text/css';
        styleElement.id = 'styles_js';
        document.getElementsByTagName('head')[0].appendChild(styleElement);
    }
    styleElement.appendChild(document.createTextNode(newStyle));
}

addNewStyle('td.EvenRow a {display:inline !important;}')

The rules added with the above method will (if you use the !important suffix) override other previously set styling. If you're not using the suffix then make sure to take concepts like 'specificity' into account.

Is it possible to change the package name of an Android app on Google Play?

Complete guide : https://developer.android.com/studio/build/application-id.html

As per Android official Blogs : https://android-developers.googleblog.com/2011/06/things-that-cannot-change.html

We can say that:

  • If the manifest package name has changed, the new application will be installed alongside the old application, so they both co-exist on the user’s device at the same time.

  • If the signing certificate changes, trying to install the new application on to the device will fail until the old version is uninstalled.

As per Google App Update check list : https://support.google.com/googleplay/android-developer/answer/113476?hl=en

Update your apps

Prepare your APK

When you're ready to make changes to your APK, make sure to update your app’s version code as well so that existing users will receive your update.

Use the following checklist to make sure your new APK is ready to update your existing users:

  • The package name of the updated APK needs to be the same as the current version.
  • The version code needs to be greater than that current version. Learn more about versioning your applications.
  • The updated APK needs to be signed with the same signature as the current version.

To verify that your APK is using the same certification as the previous version, you can run the following command on both APKs and compare the results:

$ jarsigner -verify -verbose -certs my_application.apk

If the results are identical, you’re using the same key and are ready to continue. If the results are different, you will need to re-sign the APK with the correct key.

Learn more about signing your applications

Upload your APK Once your APK is ready, you can create a new release.

Smooth scroll without the use of jQuery

Native browser smooth scrolling in JavaScript is like this:

// scroll to specific values,
// same as window.scroll() method.
// for scrolling a particular distance, use window.scrollBy().
window.scroll({
  top: 2500, 
  left: 0, 
  behavior: 'smooth' 
});

// scroll certain amounts from current position 
window.scrollBy({ 
  top: 100, // negative value acceptable
  left: 0, 
  behavior: 'smooth' 
});

// scroll to a certain element
document.querySelector('.hello').scrollIntoView({ 
  behavior: 'smooth' 
});

How do I install a color theme for IntelliJ IDEA 7.0.x

Go to File->Import Settings... and select the jar settings file

Update as of IntelliJ 2020:

Go to File -> Manage IDE Settings -> Import Settings...

Check if an array contains any element of another array in JavaScript

Update @Paul Grimshaw answer, use includes insteed of indexOf for more readable

let found = arr1.some(r=> arr2.indexOf(r) >= 0)
let found = arr1.some(r=> arr2.includes(r))

Add column to SQL query results

Manually add it when you build the query:

SELECT 'Site1' AS SiteName, t1.column, t1.column2
FROM t1

UNION ALL
SELECT 'Site2' AS SiteName, t2.column, t2.column2
FROM t2

UNION ALL
...

EXAMPLE:

DECLARE @t1 TABLE (column1 int, column2 nvarchar(1))
DECLARE @t2 TABLE (column1 int, column2 nvarchar(1))

INSERT INTO @t1
SELECT 1, 'a'
UNION SELECT 2, 'b'

INSERT INTO @t2
SELECT 3, 'c'
UNION SELECT 4, 'd'


SELECT 'Site1' AS SiteName, t1.column1, t1.column2
FROM @t1 t1

UNION ALL
SELECT 'Site2' AS SiteName, t2.column1, t2.column2
FROM @t2 t2

RESULT:

SiteName  column1  column2
Site1       1      a
Site1       2      b
Site2       3      c
Site2       4      d

iOS - Build fails with CocoaPods cannot find header files

I've found that including the library as a pod install directly helps dynamic libraries. For example, for Firebase:

pod 'RNFirebase', :path => 'path/to/node_modules/react-native-firebase/ios'

Or for ASLogger:

pod 'ASLogger', :path => 'path/to/node_modules/aslogger/ios' // path to header files

Changing or hardcoding HEADER_SEARCH_PATHS did not help me. If the error ever recurs, it's not necessary to rm -rf node_modules nor delete the pod file etc, I found it useful to clear the cache.

For react-native, I run

    rm -rf $TMPDIR/react-native-packager-cache-*
    rm -rf $TMPDIR/metro-bundler-cache-*
    rm -rf $TMPDIR/metro-* 
    rm -rf $TMPDIR/react-* 
    rm -rf $TMPDIR/haste-*
    rm -rf "$(getconf DARWIN_USER_CACHE_DIR)/org.llvm.clang/ModuleCache"
    npm start -- --reset-cache

For Xcode I remove folders in ~/Library/Developer/Xcode/DerivedData

How to calculate age (in years) based on Date of Birth and getDate()

What about a solution with only date functions, not math, not worries about leap year

CREATE FUNCTION dbo.getAge(@dt datetime) 
RETURNS int
AS
BEGIN
    RETURN 
        DATEDIFF(yy, @dt, getdate())
        - CASE 
            WHEN 
                MONTH(@dt) > MONTH(GETDATE()) OR 
                (MONTH(@dt) = MONTH(GETDATE()) AND DAY(@dt) > DAY(GETDATE())) 
            THEN 1 
            ELSE 0 
        END
END

What is a 'Closure'?

I'll give an example (in JavaScript):

function makeCounter () {
  var count = 0;
  return function () {
    count += 1;
    return count;
  }
}

var x = makeCounter();

x(); returns 1

x(); returns 2

...etc...

What this function, makeCounter, does is it returns a function, which we've called x, that will count up by one each time its called. Since we're not providing any parameters to x it must somehow remember the count. It knows where to find it based on what's called lexical scoping - it must look to the spot where it's defined to find the value. This "hidden" value is what is called a closure.

Here is my currying example again:

function add (a) {
  return function (b) {
    return a + b;
  }
}

var add3 = add(3);

add3(4); returns 7

What you can see is that when you call add with the parameter a (which is 3), that value is contained in the closure of the returned function that we're defining to be add3. That way, when we call add3 it knows where to find the a value to perform the addition.

ng-model for `<input type="file"/>` (with directive DEMO)

This is a slightly modified version that lets you specify the name of the attribute in the scope, just as you would do with ng-model, usage:

    <myUpload key="file"></myUpload>

Directive:

.directive('myUpload', function() {
    return {
        link: function postLink(scope, element, attrs) {
            element.find("input").bind("change", function(changeEvent) {                        
                var reader = new FileReader();
                reader.onload = function(loadEvent) {
                    scope.$apply(function() {
                        scope[attrs.key] = loadEvent.target.result;                                
                    });
                }
                if (typeof(changeEvent.target.files[0]) === 'object') {
                    reader.readAsDataURL(changeEvent.target.files[0]);
                };
            });

        },
        controller: 'FileUploadCtrl',
        template:
                '<span class="btn btn-success fileinput-button">' +
                '<i class="glyphicon glyphicon-plus"></i>' +
                '<span>Replace Image</span>' +
                '<input type="file" accept="image/*" name="files[]" multiple="">' +
                '</span>',
        restrict: 'E'

    };
});

how to stop a running script in Matlab

Consider having multiple matlab sessions. Keep the main session window (the pretty one with all the colours, file manager, command history, workspace, editor etc.) for running stuff that you know will terminate.

Stuff that you are experimenting with, say you are messing with ode suite and you get lots of warnings: matrix singular, because you altered some parameter and didn't predict what would happen, run in a separate session:

dos('matlab -automation -r &')

You can kill that without having to restart the whole of Matlab.

Open URL in same window and in same tab

You can do

window.close();
window.open("index.html");

and it worked successfully on my website.

How do I replace a character at a particular index in JavaScript?

There are lot of answers here, and all of them are based on two methods:

  • METHOD1: split the string using two substrings and stuff the character between them
  • METHOD2: convert the string to character array, replace one array member and join it

Personally, I would use these two methods in different cases. Let me explain.

@FabioPhms: Your method was the one I initially used and I was afraid that it is bad on string with lots of characters. However, question is what's a lot of characters? I tested it on 10 "lorem ipsum" paragraphs and it took a few milliseconds. Then I tested it on 10 times larger string - there was really no big difference. Hm.

@vsync, @Cory Mawhorter: Your comments are unambiguous; however, again, what is a large string? I agree that for 32...100kb performance should better and one should use substring-variant for this one operation of character replacement.

But what will happen if I have to make quite a few replacements?

I needed to perform my own tests to prove what is faster in that case. Let's say we have an algorithm that will manipulate a relatively short string that consists of 1000 characters. We expect that in average each character in that string will be replaced ~100 times. So, the code to test something like this is:

var str = "... {A LARGE STRING HERE} ...";

for(var i=0; i<100000; i++)
{
  var n = '' + Math.floor(Math.random() * 10);
  var p = Math.floor(Math.random() * 1000);
  // replace character *n* on position *p*
}

I created a fiddle for this, and it's here. There are two tests, TEST1 (substring) and TEST2 (array conversion).

Results:

  • TEST1: 195ms
  • TEST2: 6ms

It seems that array conversion beats substring by 2 orders of magnitude! So - what the hell happened here???

What actually happens is that all operations in TEST2 are done on array itself, using assignment expression like strarr2[p] = n. Assignment is really fast compared to substring on a large string, and its clear that it's going to win.

So, it's all about choosing the right tool for the job. Again.

PostgreSQL - max number of parameters in "IN" clause?

You might want to consider refactoring that query instead of adding an arbitrarily long list of ids... You could use a range if the ids indeed follow the pattern in your example:

SELECT * FROM user WHERE id >= minValue AND id <= maxValue;

Another option is to add an inner select:

SELECT * 
FROM user 
WHERE id IN (
    SELECT userId
    FROM ForumThreads ft
    WHERE ft.id = X
);

Removing duplicates from rows based on specific columns in an RDD/Spark DataFrame

Pyspark does include a dropDuplicates() method, which was introduced in 1.4. https://spark.apache.org/docs/latest/api/python/pyspark.sql.html#pyspark.sql.DataFrame.dropDuplicates

>>> from pyspark.sql import Row
>>> df = sc.parallelize([ \
...     Row(name='Alice', age=5, height=80), \
...     Row(name='Alice', age=5, height=80), \
...     Row(name='Alice', age=10, height=80)]).toDF()
>>> df.dropDuplicates().show()
+---+------+-----+
|age|height| name|
+---+------+-----+
|  5|    80|Alice|
| 10|    80|Alice|
+---+------+-----+

>>> df.dropDuplicates(['name', 'height']).show()
+---+------+-----+
|age|height| name|
+---+------+-----+
|  5|    80|Alice|
+---+------+-----+

How can I remove file extension from a website address?

Here is a simple PHP way that I use.
If a page is requested with the .php extension then a new request is made without the .php extension. The .php extension is then no longer shown in the browser's address field.

I came up with this solution because none of the many .htaccess suggestions worked for me and it was quicker to implement this in PHP than trying to find out why the .htaccess did not work on my server.

Put this at the beginning of each PHP file (preferrably before anything else):

include_once('scripts.php');  
strip_php_extension();  

Then put these functions in the file 'scripts.php':

//==== Strip .php extension from requested URI  
function strip_php_extension()  
{  
  $uri = $_SERVER['REQUEST_URI'];  
  $ext = substr(strrchr($uri, '.'), 1);  
  if ($ext == 'php')  
  {  
    $url = substr($uri, 0, strrpos($uri, '.'));  
    redirect($url);  
  }  
}  

//==== Redirect. Try PHP header redirect, then Java, then http redirect
function redirect($url)  
{  
  if (!headers_sent())  
  {  
    /* If headers not yet sent => do php redirect */  
    header('Location: '.$url);  
    exit;  
  }  
  else  
  {
    /* If headers already sent => do javaScript redirect */  
    echo '<script type="text/javascript">';  
    echo 'window.location.href="'.$url.'";';  
    echo '</script>';  

    /* If javaScript is disabled => do html redirect */  
    echo '<noscript>';  
    echo '<meta http-equiv="refresh" content="0; url='.$url.'" />';  
    echo '</noscript>';  
    exit;  
  }  
}  

Obviously you still need to have setup Apache to redirect any request without extension to the file with the extension. The above solution simply checks if the requested URI has an extension, if it does it requests the URI without the extension. Then Apache does the redirect to the file with the extension, but only the requested URI (without the extension) is shown in the browser's address field. The advantage is that all your "href" links in your code can still have the full filename, i.e. including the .php extension.

Easiest way to loop through a filtered list with VBA?

a = 2
x = 0

Do Until Cells(a, 1).Value = ""
If Rows(a).Hidden = False Then
x = Cells(a, 1).Value + x
End If
a = a + 1
Loop

End Sub

Use jQuery to navigate away from page

Other answers rightly point out that there is no need to use jQuery in order to navigate to another URL; that's why there's no jQuery function which does so!

If you're asking how to click a link via jQuery then assuming you have markup which looks like:

<a id="my-link" href="/relative/path.html">Click Me!</a>

You could click() it by executing:

$('#my-link').click();

Failure [INSTALL_FAILED_INVALID_APK]

Just remove old APK android/app/build/outputs/apk/debug/app-debug.apk in the folder. that's all. enjoy your coding...

What HTTP traffic monitor would you recommend for Windows?

Fiddler is great when you are only interested in the http(s) side of the communications. It is also very useful when you are trying to inspect inside a https stream.

Professional jQuery based Combobox control?

I've tried http://jqueryui.com/demos/autocomplete/#combobox and the problems faced were:

  • Cross browser rendering
  • Inability to submit custom value

As a result I've tweaked it a bit and it worked fine for me in ASP.NET MVC. My version of CSS and widget script can be found here http://saplin.blogspot.com/2011/12/html-combobox-control-and-aspnet-mvc.html

Sample on binding MVC model to custom value is also there.

Decimal or numeric values in regular expression validation

/([0-9]+[.,]*)+/ matches any number with or without coma or dots

it can match

         122
         122,354
         122.88
         112,262,123.7678

bug: it also matches 262.4377,3883 ( but it doesn't matter parctically)

Angular2: How to load data before rendering the component?

A nice solution that I've found is to do on UI something like:

<div *ngIf="isDataLoaded">
 ...Your page...
</div

Only when: isDataLoaded is true the page is rendered.

Read connection string from web.config

Everybody seems to be suggesting that adding

using System.Configuration;

which is true.

But might I suggest that you think about installing ReSharper's Visual Studio extension?

With it installed, instead of seeing an error that a class isn't defined, you'll see a prompt that tells you which assembly it is in, asking you if you want it to add the needed using statement.

svn cleanup: sqlite: database disk image is malformed

Have you seen this post on the subversion site? You could also potentially try validating and "fixing" the database directly as described here. (Note that I'm no expert, I just did a quick google search. May not be related to your issues at all).

Personally, I'd try checking out the repo again and reapplying your changes. Not sure if this is possible though in your case?

How to show empty data message in Datatables

I was finding same but lastly i found an answer. I hope this answer help you so much.

when your array is empty then you can send empty array just like

if(!empty($result))
        {
            echo json_encode($result);
        }
        else
        {
            echo json_encode(array('data'=>''));
        }

Thank you

Set Google Chrome as the debugging browser in Visual Studio

For MVC developers,

  • click on a folder in Solution Explorer (say, Controllers)
  • Select Browse With...
  • Select desired browser
  • (Optionally click ) set as Default

Add CSS to iFrame

Based on solution You've already found How to apply CSS to iframe?:

var cssLink = document.createElement("link") 
cssLink.href = "file://path/to/style.css"; 
cssLink .rel = "stylesheet"; 
cssLink .type = "text/css"; 
frames['iframe'].document.body.appendChild(cssLink);

or more jqueryish (from Append a stylesheet to an iframe with jQuery):

var $head = $("iframe").contents().find("head");                
$head.append($("<link/>", 
    { rel: "stylesheet", href: "file://path/to/style.css", type: "text/css" }));

as for security issues: Disabling same-origin policy in Safari

How to plot all the columns of a data frame in R

You could specify the title (and also the title of the axes via xlab and ylab) with the main option. E.g.:

plot(data[,i], main=names(data)[i])

And if you want to plot (and save) each variable of a dataframe, you should use png, pdf or any other graphics driver you need, and after that issue a dev.off() command. E.g.:

data <- read.csv("sample.csv",header=T,sep=",")
for (i in 1:length(data)) {
    pdf(paste('fileprefix_', names(data)[i], '.pdf', sep='')
    plot(data[,i], ylab=names(data[i]), type="l")
    dev.off()
}

Or draw all plots to the same image with the mfrow paramater of par(). E.g.: use par(mfrow=c(2,2) to include the next 4 plots in the same "image".

Convert string to variable name in python

You can use a Dictionary to keep track of the keys and values.

For instance...

dictOfStuff = {} ##Make a Dictionary

x = "Buffalo" ##OR it can equal the input of something, up to you.

dictOfStuff[x] = 4 ##Get the dict spot that has the same key ("name") as what X is equal to. In this case "Buffalo". and set it to 4. Or you can set it to  what ever you like

print(dictOfStuff[x]) ##print out the value of the spot in the dict that same key ("name") as the dictionary.

A dictionary is very similar to a real life dictionary. You have a word and you have a definition. You can look up the word and get the definition. So in this case, you have the word "Buffalo" and it's definition is 4. It can work with any other word and definition. Just make sure you put them into the dictionary first.

Keyboard shortcut to clear cell output in Jupyter notebook

For versions less than 5:

Option 1 -- quick hack:

Change the cell type to raw then back to code: EscRY will discard the output.

Option 2 -- custom shortcut (without GUI):

For this, you need to edit the custom.js file which is typically located at ~/.jupyter/custom/custom.js (if it doesn't exist, create it).

In there, you have to add

require(['base/js/namespace']) {
    // setup 'ctrl-l' as shortcut for clearing current output
    Jupyter.keyboard_manager.command_shortcuts
           .add_shortcut('ctrl-l', 'jupyter-notebook:clear-cell-output');
}

You can add shortcut there for all the fancy things you like, since the 2nd argument can be a function (docs)

If you want mappings for other standard commands, you can dump a list of all available commands by running the following in your notebook:

from IPython.core.display import Javascript

js = """
  var jc_html = "";
  var jc_array = Object.keys(IPython.notebook.keyboard_manager.command_shortcuts.actions._actions);
  for (var i=0;i<jc_array.length;i++) {
    jc_html = jc_html + jc_array[i] + "<br >";
  }
  element.html(jc_html);
  """

Javascript(data=js, lib=None, css=None)

How to make a pure css based dropdown menu?

View code online on: WebCrafts.org

HTML code:

<body id="body">
<div id="navigation">
    <h2>
        Pure CSS Drop-down Menu
    </h2>
  <div id="nav" class="nav">
    <ul>
        <li><a href="#">Menu1</a></li>
        <li>
            <a href="#">Menu2</a>
          <ul>
                <li><a href="#">Sub-Menu1</a></li>
                <li>
                    <a href="#">Sub-Menu2</a>
                  <ul>
                        <li><a href="#">Demo1</a></li>
                      <li><a href="#">Demo2</a></li>
                    </ul>
                </li>
                <li><a href="#">Sub-Menu3</a></li>
                <li><a href="#">Sub-Menu4</a></li>
            </ul>
        </li>
        <li><a href="#">Menu3</a></li>
        <li><a href="#">Menu4</a></li>
    </ul>
  </div>
</div>
</body>

Css code:

body{
    background-color:#111;
}

#navigation{
    text-align:center;
}
#navigation h2{
    color:#DDD;
}

.nav{
    display:inline-block;
    z-index:5;
    font-weight:bold;
}
.nav ul{
    width:auto;
    list-style:none;
}

.nav ul li{
    display:inline-block;
}

.nav ul li a{
    text-decoration:none;
    text-align:center;
    color:#222;
    display:block;
    width:120px;
    line-height:30px;
    background-color:gray;
}

.nav ul li a:hover{
    background-color:#EEC;   
}
.nav ul li ul{
    margin-top:0px;
    padding-left:0px;
    position:absolute;
    display:none;
}

.nav ul li:hover ul{
    display:block;
}

.nav ul li ul li{
    display:block;
}

.nav ul li ul li ul{
    margin-left:100%;
    margin-top:-30px;
    visibility:hidden;
}

.nav ul li ul li:hover ul{
    margin-left:100%;
    visibility:visible;
}

MVC Razor view nested foreach's model

It is clear from the error.

The HtmlHelpers appended with "For" expects lambda expression as a parameter.

If you are passing the value directly, better use Normal one.

e.g.

Instead of TextboxFor(....) use Textbox()

syntax for TextboxFor will be like Html.TextBoxFor(m=>m.Property)

In your scenario you can use basic for loop, as it will give you index to use.

@for(int i=0;i<Model.Theme.Count;i++)
 {
   @Html.LabelFor(m=>m.Theme[i].name)
   @for(int j=0;j<Model.Theme[i].Products.Count;j++) )
     {
      @Html.LabelFor(m=>m.Theme[i].Products[j].name)
      @for(int k=0;k<Model.Theme[i].Products[j].Orders.Count;k++)
          {
           @Html.TextBoxFor(m=>Model.Theme[i].Products[j].Orders[k].Quantity)
           @Html.TextAreaFor(m=>Model.Theme[i].Products[j].Orders[k].Note)
           @Html.EditorFor(m=>Model.Theme[i].Products[j].Orders[k].DateRequestedDeliveryFor)
      }
   }
}

Tri-state Check box in HTML?

As I needed something like this -without any plug-in- for script-generated checkboxes in a table... I ended up with this solution:

<!DOCTYPE html>
<html>
<body>

Toto <input type="checkbox" id="myCheck1" onclick="updateChkBx(this)" /><br />
Tutu <input type="checkbox" id="myCheck2" onclick="updateChkBx(this)" /><br />
Tata <input type="checkbox" id="myCheck3" onclick="updateChkBx(this)" /><br />
Tete <input type="checkbox" id="myCheck4" onclick="updateChkBx(this)" /><br />

<script>
var chkBoxState = [];

function updateChkBx(src) {
  var idx = Number(src.id.substring(7)); // 7 to bypass the "myCheck" part in each checkbox id
  if(typeof chkBoxState[idx] == "undefined") chkBoxState[idx] = false; // make sure we can use stored state at first call
  
  // the problem comes from a click on a checkbox both toggles checked attribute and turns inderminate attribute to false
  if(chkBoxState[idx]) {
    src.indeterminate = false;
    src.checked = false;
    chkBoxState[idx] = false;
  }
  else if (!src.checked) { // passing from checked to unchecked
    src.indeterminate = true;
    src.checked = true; // force considering we are in a checked state
    chkBoxState[idx] = true;
  }
}
// to know box state, just test indeterminate, and if not indeterminate, test checked
</script>

</body>
</html>

Enable CORS in Web API 2

 var cors = new EnableCorsAttribute("*","*","*");
 config.EnableCors(cors);

 var constraints = new {httpMethod = new HttpMethodConstraint(HttpMethod.Options)};
 config.Routes.IgnoreRoute("OPTIONS", "*pathInfo",constraints);

TSQL CASE with if comparison in SELECT statement

You can try with this:

WITH CTE_A As (SELECT COUNT(*) as articleNumber,A.UserID  as UserID FROM Articles A
           Inner Join Users U
           on  A.userId = U.userId 
           Group By A.userId , U.userId   ),

B as (Select us.registrationDate,

      CASE
         WHEN CTE_A.articleNumber < 2 THEN 'Ama'
         WHEN CTE_A.articleNumber < 5 THEN 'SemiAma' 
         WHEN CTE_A.articleNumber < 7 THEN 'Good'  
         WHEN CTE_A.articleNumber < 9 THEN 'Better' 
         WHEN CTE_A.articleNumber < 12 THEN 'Best'
         ELSE 'Outstanding'
         END as Ranking,
         us.hobbies, etc...
         FROM USERS Us Inner Join CTE_A 
         on CTE_A.UserID=us.UserID)

Select * from B

How to disable mouse right click on a web page?

There are plenty of examples of this which can be found via Google

However, users can turn off Javascript to stop this highly annoying "feature". I think you should really think about this before implementing it. It isn't really going to protect your content (if that is what you are trying achieve).

There is an article here that illustrates just how annoying and pointless it is.

How to Create a script via batch file that will uninstall a program if it was installed on windows 7 64-bit or 32-bit

In my experience, to use wmic in a script, you need to get the nested quoting right:

wmic product where "name = 'Windows Azure Authoring Tools - v2.3'" call uninstall /nointeractive 

quoting both the query and the name. But wmic will only uninstall things installed via windows installer.

Can I apply the required attribute to <select> fields in HTML5?

The <select> element does support the required attribute, as per the spec:

Which browser doesn’t honour this?

(Of course, you have to validate on the server anyway, as you can’t guarantee that users will have JavaScript enabled.)

Convert and format a Date in JSP

Date td = new Date();
String b = new String("");
SimpleDateFormat format = new SimpleDateFormat("YYYY/MM/dd");
b = format.format(td);
out.println(b);           

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

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

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

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

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

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

getObject map QueueManager.add

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

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

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

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

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

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

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

or:

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

Setting an int to Infinity in C++

This is a message for me in the future:

Just use: (unsigned)!((int)0)

It creates the largest possible number in any machine by assigning all bits to 1s (ones) and then casts it to unsigned

Even better

#define INF (unsigned)!((int)0)

And then just use INF in your code

Get first and last day of month using threeten, LocalDate

The API was designed to support a solution that matches closely to business requirements

import static java.time.temporal.TemporalAdjusters.*;

LocalDate initial = LocalDate.of(2014, 2, 13);
LocalDate start = initial.with(firstDayOfMonth());
LocalDate end = initial.with(lastDayOfMonth());

However, Jon's solutions are also fine.

Check whether a value exists in JSON object

Below function can be used to check for a value in any level in a JSON

function _isContains(json, value) {
    let contains = false;
    Object.keys(json).some(key => {
        contains = typeof json[key] === 'object' ? _isContains(json[key], value) : json[key] === value;
         return contains;
    });
    return contains;
 }

then to check if JSON contains the value

_isContains(JSONObject, "dog")

See this fiddle: https://jsfiddle.net/ponmudi/uykaacLw/

Most of the answers mentioned here compares by 'name' key. But no need to care about the key, can just checks if JSON contains the given value. So that the function can be used to find any value irrespective of the key.

Fatal error: Call to a member function query() on null

put this line in parent construct : $this->load->database();

function  __construct() {
    parent::__construct();
    $this->load->library('lib_name');
    $model=array('model_name');
    $this->load->model($model);
    $this->load->database();
}

this way.. it should work..

How do I set the default font size in Vim?

I cross over the same problem I put the following code in the folder ~/.gvimrc and it works.

set guifont=Monaco:h20

Index of element in NumPy array

Use np.where to get the indices where a given condition is True.

Examples:

For a 2D np.ndarray called a:

i, j = np.where(a == value) # when comparing arrays of integers

i, j = np.where(np.isclose(a, value)) # when comparing floating-point arrays

For a 1D array:

i, = np.where(a == value) # integers

i, = np.where(np.isclose(a, value)) # floating-point

Note that this also works for conditions like >=, <=, != and so forth...

You can also create a subclass of np.ndarray with an index() method:

class myarray(np.ndarray):
    def __new__(cls, *args, **kwargs):
        return np.array(*args, **kwargs).view(myarray)
    def index(self, value):
        return np.where(self == value)

Testing:

a = myarray([1,2,3,4,4,4,5,6,4,4,4])
a.index(4)
#(array([ 3,  4,  5,  8,  9, 10]),)

Remove Primary Key in MySQL

I believe Quassnoi has answered your direct question. Just a side note: Maybe this is just some awkward wording on your part, but you seem to be under the impression that you have three primary keys, one on each field. This is not the case. By definition, you can only have one primary key. What you have here is a primary key that is a composite of three fields. Thus, you cannot "drop the primary key on a column". You can drop the primary key, or not drop the primary key. If you want a primary key that only includes one column, you can drop the existing primary key on 3 columns and create a new primary key on 1 column.

SQL: How to get the count of each distinct value in a column?

SELECT
  category,
  COUNT(*) AS `num`
FROM
  posts
GROUP BY
  category

ERROR 1044 (42000): Access denied for 'root' With All Privileges

The reason i could not delete some of the users via 'drop' statement was that there is a bug in Mysql http://bugs.mysql.com/bug.php?id=62255 with hostname containing upper case letters. The solution was running following query:

DELETE FROM mysql.user where host='Some_Host_With_UpperCase_Letters';

I am still trying to figure the other issue where the root user with all permissions are unable to grant privileges to new user for particular database

C++ pass an array by reference

Yes, but when argument matching for a reference, the implicit array to pointer isn't automatic, so you need something like:

void foo( double (&array)[42] );

or

void foo( double (&array)[] );

Be aware, however, that when matching, double [42] and double [] are distinct types. If you have an array of an unknown dimension, it will match the second, but not the first, and if you have an array with 42 elements, it will match the first but not the second. (The latter is, IMHO, very counter-intuitive.)

In the second case, you'll also have to pass the dimension, since there's no way to recover it once you're inside the function.

How to make gradient background in android

Following link may help you http://angrytools.com/gradient/ .This will create custom gradient background in android as like in photoshop.

Complex nesting of partials and templates

You may checkout this library for the same purpose also:

http://angular-route-segment.com

It looks like what you are looking for, and it is much simpler to use than ui-router. From the demo site:

JS:

$routeSegmentProvider.

when('/section1',          's1.home').
when('/section1/:id',      's1.itemInfo.overview').
when('/section2',          's2').

segment('s1', {
    templateUrl: 'templates/section1.html',
    controller: MainCtrl}).
within().
    segment('home', {
        templateUrl: 'templates/section1/home.html'}).
    segment('itemInfo', {
        templateUrl: 'templates/section1/item.html',
        controller: Section1ItemCtrl,
        dependencies: ['id']}).
    within().
        segment('overview', {
            templateUrl: 'templates/section1/item/overview.html'}).

Top-level HTML:

<ul>
    <li ng-class="{active: $routeSegment.startsWith('s1')}">
        <a href="/section1">Section 1</a>
    </li>
    <li ng-class="{active: $routeSegment.startsWith('s2')}">
        <a href="/section2">Section 2</a>
    </li>
</ul>
<div id="contents" app-view-segment="0"></div>

Nested HTML:

<h4>Section 1</h4>
Section 1 contents.
<div app-view-segment="1"></div>

jQuery events .load(), .ready(), .unload()

If both "document.ready" variants are used they will both fire, in the order of appearance

$(function(){
    alert('shorthand document.ready');
});

//try changing places
$(document).ready(function(){
    alert('document.ready');
});

How do I get the color from a hexadecimal color code using .NET?

If you want to do it with a Windows Store App, following by @Hans Kesting and @Jink answer:

    string colorcode = "#FFEEDDCC";
    int argb = Int32.Parse(colorcode.Replace("#", ""), NumberStyles.HexNumber);
    tData.DefaultData = Color.FromArgb((byte)((argb & -16777216) >> 0x18),
                          (byte)((argb & 0xff0000) >> 0x10),
                          (byte)((argb & 0xff00) >> 8),
                          (byte)(argb & 0xff));

Execution failed for task 'app:mergeDebugResources' Crunching Cruncher....png failed

This error was caused for me because of the path where my project was located. There was a blank space in one folder, for example,

Folder\Another Folder\MyAndroidProjects\...

Changing it to Folder\AnotherFolder\MyAndroidProjects\... and resynchronising Gradle resolved this for me.

How to escape special characters in building a JSON string?

Use encodeURIComponent() to encode the string.

Eg.:

var product_list = encodeURIComponent(JSON.stringify(product_list));

You don't need to decode it since the web server automatically do the same.

Error: macro names must be identifiers using #ifdef 0

Use the following to evaluate an expression (constant 0 evaluates to false).

#if 0
 ...
#endif

How to merge multiple dicts with same key or different key?

assuming all keys are always present in all dicts:

ds = [d1, d2]
d = {}
for k in d1.iterkeys():
    d[k] = tuple(d[k] for d in ds)

Note: In Python 3.x use below code:

ds = [d1, d2]
d = {}
for k in d1.keys():
  d[k] = tuple(d[k] for d in ds)

and if the dic contain numpy arrays:

ds = [d1, d2]
d = {}
for k in d1.keys():
  d[k] = np.concatenate(list(d[k] for d in ds))

Critical t values in R

Extending @Ryogi answer above, you can take advantage of the lower.tail parameter like so:

qt(0.25/2, 40, lower.tail = FALSE) # 75% confidence

qt(0.01/2, 40, lower.tail = FALSE) # 99% confidence

How to use Google App Engine with my own naked domain (not subdomain)?

For App Engine in 2019, googles has made it easier to set up a custom domain.

  1. Google App Engine -> Settings -> Custom Domains

  2. Verify your domain

  3. Select Your Domain Name Registra

Reminder: Use TXT Record with the value Google provides without a existing CNAME record, otherwise TXT Record will be override

  1. Follow the steps on the page, which includes the configuration of your subdomain, CNAME Record, A Record, AAAA Record, and you'll be good to go.

How to execute function in SQL Server 2008

I have come to this question and the one below several times.

how to call scalar function in sql server 2008

Each time, I try entering the Function using the syntax shown here in SQL Server Management Studio, or SSMS, to see the results, and each time I get the errors.

For me, that is because my result set is in tabular data format. Therefore, to see the results in SSMS, I have to call it like this:

SELECT * FROM dbo.Afisho_rankimin_TABLE(5);

I understand that the author's question involved a scalar function, so this answer is only to help others who come to StackOverflow often when they have a problem with a query (like me).

I hope this helps others.

continuous page numbering through section breaks

You can check out this post on SuperUser.

Word starts page numbering over for each new section by default.

I do it slightly differently than the post above that goes through the ribbon menus, but in both methods you have to go through the document to each section's beginning.

My method:

  • open up the footer (or header if that's where your page number is)
  • drag-select the page number
  • right-click on it
  • hit Format Page Numbers
  • click on the Continue from Previous Section radio button under Page numbering

I find this right-click method to be a little faster. Also, usually if I insert the page numbers first before I start making any new sections, this problem doesn't happen in the first place.

C++ deprecated conversion from string constant to 'char*'

Maybe you can try this:

void foo(const char* str) 
{
    // Do something
}

foo("Hello")

It works for me

How to get the last element of a slice?

For just reading the last element of a slice:

sl[len(sl)-1]

For removing it:

sl = sl[:len(sl)-1]

See this page about slice tricks

In Python How can I declare a Dynamic Array

Here's a great method I recently found on a different stack overflow post regarding multi-dimensional arrays, but the answer works beautifully for single dimensional arrays as well:

# Create an 8 x 5 matrix of 0's:
w, h = 8, 5;
MyMatrix = [ [0 for x in range( w )] for y in range( h ) ]  

# Create an array of objects:
MyList = [ {} for x in range( n ) ]

I love this because you can specify the contents and size dynamically, in one line!

One more for the road:

# Dynamic content initialization:
MyFunkyArray = [ x * a + b for x in range ( n ) ]

Getter and Setter declaration in .NET

Lets start with 3. That wouldnt work. public getMyProperty() has no return typ.

And number 1 and 2 are actually same things. 2 is what number 1 becomes after compilation.

So 1 and 2 are same things. with two you can have some validation or caching in your model.

other than that they become same.

Matplotlib connect scatterplot points with line - Python

In addition to what provided in the other answers, the keyword "zorder" allows one to decide the order in which different objects are plotted vertically. E.g.:

plt.plot(x,y,zorder=1) 
plt.scatter(x,y,zorder=2)

plots the scatter symbols on top of the line, while

plt.plot(x,y,zorder=2)
plt.scatter(x,y,zorder=1)

plots the line over the scatter symbols.

See, e.g., the zorder demo

Wrap long lines in Python

I'm surprised no one mentioned the implicit style above. My preference is to use parens to wrap the string while lining the string lines up visually. Personally I think this looks cleaner and more compact than starting the beginning of the string on a tabbed new line.

Note that these parens are not part of a method call — they're only implicit string literal concatenation.

Python 2:

def fun():
    print ('{0} Here is a really '
           'long sentence with {1}').format(3, 5)

Python 3 (with parens for print function):

def fun():
    print(('{0} Here is a really '
           'long sentence with {1}').format(3, 5))

Personally I think it's cleanest to separate concatenating the long string literal from printing it:

def fun():
    s = ('{0} Here is a really '
         'long sentence with {1}').format(3, 5)
    print(s)

SQL Server equivalent to Oracle's CREATE OR REPLACE VIEW

For reference from SQL Server 2016 SP1+ you could use CREATE OR ALTER VIEW syntax.

MSDN CREATE VIEW:

CREATE [ OR ALTER ] VIEW [ schema_name . ] view_name [ (column [ ,...n ] ) ]   
[ WITH <view_attribute> [ ,...n ] ]   
AS select_statement   
[ WITH CHECK OPTION ]   
[ ; ]

OR ALTER

Conditionally alters the view only if it already exists.

db<>fiddle demo

Flask Value error view function did not return a response

The following does not return a response:

You must return anything like return afunction() or return 'a string'.

This can solve the issue

Why does the jquery change event not trigger when I set the value of a select using val()?

Adding this piece of code after the val() seems to work:

$(":input#single").trigger('change');

JavaScript blob filename without link

Same principle as the solutions above. But I had issues with Firefox 52.0 (32 bit) where large files (>40 MBytes) are truncated at random positions. Re-scheduling the call of revokeObjectUrl() fixes this issue.

function saveFile(blob, filename) {
  if (window.navigator.msSaveOrOpenBlob) {
    window.navigator.msSaveOrOpenBlob(blob, filename);
  } else {
    const a = document.createElement('a');
    document.body.appendChild(a);
    const url = window.URL.createObjectURL(blob);
    a.href = url;
    a.download = filename;
    a.click();
    setTimeout(() => {
      window.URL.revokeObjectURL(url);
      document.body.removeChild(a);
    }, 0)
  }
}

jsfiddle example

Show/hide image with JavaScript

This is working code:

<html>
  <body bgcolor=cyan>
    <img src ="backgr1.JPG" id="my" width="310" height="392" style="position: absolute; top:92px; left:375px; visibility:hidden"/>
    <script type="text/javascript">
      function tend() {
        document.getElementById('my').style.visibility='visible';
      }
      function tn() {
        document.getElementById('my').style.visibility='hidden';
      }
    </script>
    <input type="button" onclick="tend()" value="back">
    <input type="button" onclick="tn()" value="close">
  </body>
</html>

How to set textColor of UILabel in Swift

This code example that follows shows a basic UILabel configuration.

let lbl = UILabel(frame: CGRectMake(0, 0, 300, 200))
lbl.text = "yourString"

// Enum type, two variations:
lbl.textAlignment = NSTextAlignment.Right
lbl.textAlignment = .Right

lbl.textColor = UIColor.red
lbl.shadowColor = UIColor.black
lbl.font = UIFont(name: "HelveticaNeue", size: CGFloat(22))
self.view.addSubview(lbl)

Why am I getting tree conflicts in Subversion?

This can be caused by not using the same version clients all over.

Using a version 1.5 client and a version 1.6 client towards the same repository can create this kind of problem. (I was just bitten myself.)

How to show android checkbox at right side?

As suggested by @The Berga You can add android:layoutDirection="rtl" but it's only available with API 17.
for dynamic implementation, here it goes

chkBox.setLayoutDirection(View.LAYOUT_DIRECTION_RTL);

Index was out of range. Must be non-negative and less than the size of the collection parameter name:index

This error is caused when you have enabled paging in Grid view. If you want to delete a record from grid then you have to do something like this.

int index = Convert.ToInt32(e.CommandArgument);
int i = index % 20;
// Here 20 is my GridView's Page Size.
GridViewRow row = gvMainGrid.Rows[i];
int id = Convert.ToInt32(gvMainGrid.DataKeys[i].Value);
new GetData().DeleteRecord(id);
GridView1.DataSource = RefreshGrid();
GridView1.DataBind();

Hope this answers the question.

How do I move a file (or folder) from one folder to another in TortoiseSVN?

To move a file or set of files using Tortoise SVN, right-click-and-drag the target files to their destination and release the right mouse button. The popup menu will have a SVN move versioned files here option.

Note that the destination folder must have already been added to the repository for the SVN move versioned files here option to appear.

PHP max_input_vars

Use of this directive mitigates the possibility of denial of service attacks which use hash collisions. If there are more input variables than specified by this directive, an E_WARNING is issued, and further input variables are truncated from the request.

I can suggest not to extend the default value which is 1000 and extend the application functionality by serialising the request or send the request by blocks. Otherwise, you can extend this to configuration needed.

It definitely needs to set up in the php.ini

Send form data with jquery ajax json

The accepted answer here indeed makes a json from a form, but the json contents is really a string with url-encoded contents.

To make a more realistic json POST, use some solution from Serialize form data to JSON to make formToJson function and add contentType: 'application/json;charset=UTF-8' to the jQuery ajax call parameters.

$.ajax({
    url: 'test.php',
    type: "POST",
    dataType: 'json',
    data: formToJson($("form")),
    contentType: 'application/json;charset=UTF-8',
    ...
})

Apache: Restrict access to specific source IP inside virtual host

For Apache 2.4, you would use the Require IP directive. So to only allow machines from the 192.168.0.0/24 network (range 192.168.0.0 - 192.168.0.255)

<VirtualHost *:80>
    <Location />
      Require ip 192.168.0.0/24
    </Location>
    ...
</VirtualHost>

And if you just want the localhost machine to have access, then there's a special Require local directive.

The local provider allows access to the server if any of the following conditions is true:

  • the client address matches 127.0.0.0/8
  • the client address is ::1
  • both the client and the server address of the connection are the same

This allows a convenient way to match connections that originate from the local host:

<VirtualHost *:80>
    <Location />
      Require local
    </Location>
    ...
</VirtualHost>

Binary numbers in Python

Not sure if helpful, but I leave my solution here:

class Solution:
    # @param A : string
    # @param B : string
    # @return a strings
    def addBinary(self, A, B):
        num1 = bin(int(A, 2))
        num2 = bin(int(B, 2))
        bin_str = bin(int(num1, 2)+int(num2, 2))
        b_index = bin_str.index('b')
        return bin_str[b_index+1:]

s = Solution()
print(s.addBinary("11", "100"))

babel-loader jsx SyntaxError: Unexpected token

I ran into a similar issue when migrating from babel 5 to babel 6.

I was just running babel to compile the src to lib folder babel src --out-dir lib

I will share my setup for babel 6:

Ensure you have the following babel 6 devDependencies installed

"babel-core": "^6.7.6",
"babel-loader": "^6.2.4",
"babel-preset-es2015": "^6.6.0",
"babel-preset-react": "^6.5.0",
"babel-preset-stage-0": "^6.5.0"

Add your .babelrc file to the project:

{
  "presets": ["es2015", "stage-0", "react"]
}

Why does an image captured using camera intent gets rotated on some devices on Android?

Here is Xamarin.Android version:

From @Jason Robinson's answer:

Bitmap rotate(Bitmap bitmap, int angle)
{
    var matrix = new Matrix();
    matrix.PostRotate(angle);

    return Bitmap.CreateBitmap(bitmap, 0, 0, bitmap.Width, bitmap.Height, matrix, true);
}

Bitmap rotateIfRequired(Bitmap bitmap, string imagePath)
{
    var ei = new ExifInterface(imagePath);
    var orientation = ei.GetAttributeInt(ExifInterface.TagOrientation, (int)Android.Media.Orientation.Undefined);

    switch (orientation)
    {
        case (int)Android.Media.Orientation.Rotate90: return rotate(bitmap, 90);
        case (int)Android.Media.Orientation.Rotate180: return rotate(bitmap, 180);
        case (int)Android.Media.Orientation.Rotate270: return rotate(bitmap, 270);
        default: return bitmap;
    }
}

Then calculateInSampleSize method:

int calculateInSampleSize(BitmapFactory.Options options, int reqW, int reqH)
{
    float h = options.OutHeight;
    float w = options.OutWidth;
    var inSampleSize = 1;

    if (h > reqH || w > reqW)
    {
        if (reqH == 0) inSampleSize = (int)Math.Floor(w / reqW);
        else if (reqW == 0) inSampleSize = (int)Math.Floor(h / reqH);
        else
        {
            var hRatio = (int)Math.Floor(h / reqH);
            var wRatio = (int)Math.Floor(w / reqW);
            inSampleSize = false ? Math.Max(hRatio, wRatio) : Math.Min(hRatio, wRatio);
        }
    }

    return inSampleSize;
}

From @Sami Eltamawy's answer:

Bitmap handleSamplingAndRotationBitmap(string imagePath)
{
    var maxHeight = 1024;
    var maxWidth = 1024;

    var options = new BitmapFactory.Options();
    options.InJustDecodeBounds = true;
    BitmapFactory.DecodeFile(imagePath, options);

    options.InSampleSize = calculateInSampleSize(options, maxWidth, maxHeight);

    options.InJustDecodeBounds = false;

    var bitmap = BitmapFactory.DecodeFile(imagePath, options);

    bitmap = rotateIfRequired(bitmap, imagePath);

    return bitmap;
}

Gson: How to exclude specific fields from Serialization without annotations

I solved this problem with custom annotations. This is my "SkipSerialisation" Annotation class:

@Target (ElementType.FIELD)
public @interface SkipSerialisation {

}

and this is my GsonBuilder:

gsonBuilder.addSerializationExclusionStrategy(new ExclusionStrategy() {

  @Override public boolean shouldSkipField (FieldAttributes f) {

    return f.getAnnotation(SkipSerialisation.class) != null;

  }

  @Override public boolean shouldSkipClass (Class<?> clazz) {

    return false;
  }
});

Example :

public class User implements Serializable {

  public String firstName;

  public String lastName;

  @SkipSerialisation
  public String email;
}

Are there best practices for (Java) package organization?

Package organization or package structuring is usually a heated discussion. Below are some simple guidelines for package naming and structuring:

  • Follow java package naming conventions
  • Structure your packages according to their functional role as well as their business role
    • Break down your packages according to their functionality or modules. e.g. com.company.product.modulea
    • Further break down could be based on layers in your software. But don't go overboard if you have only few classes in the package, then it makes sense to have everything in the package. e.g. com.company.product.module.web or com.company.product.module.util etc.
    • Avoid going overboard with structuring, IMO avoid separate packaging for exceptions, factories, etc. unless there's a pressing need.
  • If your project is small, keep it simple with few packages. e.g. com.company.product.model and com.company.product.util, etc.
  • Take a look at some of the popular open source projects out there on Apache projects. See how they use structuring, for various sized projects.
  • Also consider build and distribution when naming ( allowing you to distribute your api or SDK in a different package, see servlet api)

After a few experiments and trials you should be able to come up with a structuring that you are comfortable with. Don't be fixated on one convention, be open to changes.

How To limit the number of characters in JTextField?

Just put this code in KeyTyped event:

    if ((jtextField.getText() + evt.getKeyChar()).length() > 20) {
        evt.consume();
    }

Where "20" is the maximum number of characters that you want.

Android: Quit application when press back button

When you press back and then you finish your current activity(say A), you see a blank activity with your app logo(say B), this simply means that activity B which is shown after finishing A is still in backstack, and also activity A was started from activity B, so in activity, You should start activity A with flags as

Intent launchNextActivity;
launchNextActivity = new Intent(B.class, A.class);
launchNextActivity.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
launchNextActivity.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);                  
launchNextActivity.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
startActivity(launchNextActivity);

Now your activity A is top on stack with no other activities of your application on the backstack.

Now in the activity A where you want to implement onBackPressed to close the app, you may do something like this,

private Boolean exit = false;
@Override
    public void onBackPressed() {
        if (exit) {
            finish(); // finish activity
        } else {
            Toast.makeText(this, "Press Back again to Exit.",
                    Toast.LENGTH_SHORT).show();
            exit = true;
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    exit = false;
                }
            }, 3 * 1000);

        }

    }

The Handler here handles accidental back presses, it simply shows a Toast, and if there is another back press within 3 seconds, it closes the application.

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

A few considerations on the subject:

  • The parenthesis:

    The browser (engine/parser) associates the keyword function with

    [optional name]([optional parameters]){...code...}
    

    So in an expression like function(){}() the last parenthesis makes no sense.

    Now think at

    name=function(){} ; name() !?
    

Yes, the first pair of parenthesis force the anonymous function to turn into a variable (stored expression) and the second launches evaluation/execution, so ( function(){} )() makes sense.

  • The utility: ?

    1. For executing some code on load and isolate the used variables from the rest of the page especially when name conflicts are possible;

    2. Replace eval("string") with

      (new Function("string"))()

    3. Wrap long code for " =?: " operator like:

      result = exp_to_test ? (function(){... long_code ...})() : (function(){...})();

How to get EditText value and display it on screen through TextView?

in "String.xml" you can notice any String or value you want to use, here are two examples:

<string name="app_name">My Calculator App
    </string>
<color name="color_menu_home">#ffcccccc</color>

Used for the layout.xml: android:text="@string/app_name"

The advantage: you can use them as often you want, you only need to link them in your Layout-xml, and you can change the String-Content easily in the strings.xml, without searching in your source-code for the right position. Important for changing language, you only need to replace the strings.xml - file

How to write a simple Html.DropDownListFor()?

@using (Html.BeginForm()) {
    <p>Do you like pizza?
        @Html.DropDownListFor(x => x.likesPizza, new[] {
            new SelectListItem() {Text = "Yes", Value = bool.TrueString},
            new SelectListItem() {Text = "No", Value = bool.FalseString}
        }, "Choose an option") 
    </p>
    <input type = "submit" value = "Submit my answer" />
} 

I think this answer is similar to Berat's, in that you put all the code for your DropDownList directly in the view. But I think this is an efficient way of creating a y/n (boolean) drop down list, so I wanted to share it.

Some notes for beginners:

  • Don't worry about what 'x' is called - it is created here, for the first time, and doesn't link to anything else anywhere else in the MVC app, so you can call it what you want - 'x', 'model', 'm' etc.
  • The placeholder that users will see in the dropdown list is "Choose an option", so you can change this if you want.
  • There's a bit of text preceding the drop down which says "Do you like pizza?"
  • This should be complete text for a form, including a submit button, I think

Hope this helps someone,

how to find array size in angularjs

You can find the number of members in a Javascript array by using its length property:

var number = $scope.names.length;

Docs - Array.prototype.length

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).

Root element is missing

Just in case anybody else lands here from Google, I was bitten by this error message when using XDocument.Load(Stream) method.

XDocument xDoc = XDocument.Load(xmlStream);  

Make sure the stream position is set to 0 (zero) before you try and load the Stream, its an easy mistake I always overlook!

if (xmlStream.Position > 0)
{
    xmlStream.Position = 0;
}
XDocument xDoc = XDocument.Load(xmlStream); 

NuGet Packages are missing

In my case there was missing <RestorePackages>true</RestorePackages> in *.csproj file. It was not necessary to delete snippets of code I see in previous answers.

jquery: animate scrollLeft

You'll want something like this:


$("#next").click(function(){
      var currentElement = currentElement.next();
      $('html, body').animate({scrollLeft: $(currentElement).offset().left}, 800);
      return false;
   }); 
I believe this should work, it's adopted from a scrollTop function.

Access Form - Syntax error (missing operator) in query expression

No, no, no.

These answers are all wrong. There is a fundamental absence of knowledge in your brain that I'm going to remedy right now.

Your major issue here is your naming scheme. It's verbose, contains undesirable characters, and is horribly inconsistent.

First: A table that is called Salesperson does not need to have each field in the table called Salesperson.Salesperson number, Salesperson.Salesperson email. You're already in the table Salesperson. Everything in this table relates to Salesperson. You don't have to keep saying it.

Instead use ID, Email. Don't use Number because that's probably a reserved word. Do you really endeavour to type [] around every field name for the lifespan of your database?

Primary keys on a table called Student can either be ID or StudentID but be consistent. Foreign keys should only be named by the table it points to followed by ID. For example: Student.ID and Appointment.StudentID. ID is always capitalized. I don't care if your IDE tells you not to because everywhere but your IDE will be ID. Even Access likes ID.

Second: Name all your fields without spaces or special characters and keep them as short as possible and if they conflict with a reserved word, find another word.

Instead of: phone number use PhoneNumber or even better, simply, Phone. If you choose what time user made the withdrawal, you're going to have to type that in every single time.

Third: And this one is the most important one: Always be consistent in whatever naming scheme you choose. You should be able to say, "I need the postal code from that table; its name is going to be PostalCode." You should know that without even having to look it up because you were consistent in your naming convention.

Recap: Terse, not verbose. Keep names short with no spaces, don't repeat the table name, don't use reserved words, and capitalize each word. Above all, be consistent.

I hope you take my advice. This is the right way to do it. My answer is the right one. You should be extremely pedantic with your naming scheme to the point of absolute obsession for the rest of your lives on this planet.

NOTE:You actually have to change the field name in the design view of the table and in the query.

Where do I put image files, css, js, etc. in Codeigniter?

I use the following folder structure:

application 
system 
static
    admin
        js
        css
        images
    public
        js
        css
        images
    uploads
        original
        thumbs

Logical operators for boolean indexing in Pandas

TLDR; Logical Operators in Pandas are &, | and ~, and parentheses (...) is important!

Python's and, or and not logical operators are designed to work with scalars. So Pandas had to do one better and override the bitwise operators to achieve vectorized (element-wise) version of this functionality.

So the following in python (exp1 and exp2 are expressions which evaluate to a boolean result)...

exp1 and exp2              # Logical AND
exp1 or exp2               # Logical OR
not exp1                   # Logical NOT

...will translate to...

exp1 & exp2                # Element-wise logical AND
exp1 | exp2                # Element-wise logical OR
~exp1                      # Element-wise logical NOT

for pandas.

If in the process of performing logical operation you get a ValueError, then you need to use parentheses for grouping:

(exp1) op (exp2)

For example,

(df['col1'] == x) & (df['col2'] == y) 

And so on.


Boolean Indexing: A common operation is to compute boolean masks through logical conditions to filter the data. Pandas provides three operators: & for logical AND, | for logical OR, and ~ for logical NOT.

Consider the following setup:

np.random.seed(0)
df = pd.DataFrame(np.random.choice(10, (5, 3)), columns=list('ABC'))
df

   A  B  C
0  5  0  3
1  3  7  9
2  3  5  2
3  4  7  6
4  8  8  1

Logical AND

For df above, say you'd like to return all rows where A < 5 and B > 5. This is done by computing masks for each condition separately, and ANDing them.

Overloaded Bitwise & Operator
Before continuing, please take note of this particular excerpt of the docs, which state

Another common operation is the use of boolean vectors to filter the data. The operators are: | for or, & for and, and ~ for not. These must be grouped by using parentheses, since by default Python will evaluate an expression such as df.A > 2 & df.B < 3 as df.A > (2 & df.B) < 3, while the desired evaluation order is (df.A > 2) & (df.B < 3).

So, with this in mind, element wise logical AND can be implemented with the bitwise operator &:

df['A'] < 5

0    False
1     True
2     True
3     True
4    False
Name: A, dtype: bool

df['B'] > 5

0    False
1     True
2    False
3     True
4     True
Name: B, dtype: bool

(df['A'] < 5) & (df['B'] > 5)

0    False
1     True
2    False
3     True
4    False
dtype: bool

And the subsequent filtering step is simply,

df[(df['A'] < 5) & (df['B'] > 5)]

   A  B  C
1  3  7  9
3  4  7  6

The parentheses are used to override the default precedence order of bitwise operators, which have higher precedence over the conditional operators < and >. See the section of Operator Precedence in the python docs.

If you do not use parentheses, the expression is evaluated incorrectly. For example, if you accidentally attempt something such as

df['A'] < 5 & df['B'] > 5

It is parsed as

df['A'] < (5 & df['B']) > 5

Which becomes,

df['A'] < something_you_dont_want > 5

Which becomes (see the python docs on chained operator comparison),

(df['A'] < something_you_dont_want) and (something_you_dont_want > 5)

Which becomes,

# Both operands are Series...
something_else_you_dont_want1 and something_else_you_dont_want2

Which throws

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

So, don't make that mistake!1

Avoiding Parentheses Grouping
The fix is actually quite simple. Most operators have a corresponding bound method for DataFrames. If the individual masks are built up using functions instead of conditional operators, you will no longer need to group by parens to specify evaluation order:

df['A'].lt(5)

0     True
1     True
2     True
3     True
4    False
Name: A, dtype: bool

df['B'].gt(5)

0    False
1     True
2    False
3     True
4     True
Name: B, dtype: bool

df['A'].lt(5) & df['B'].gt(5)

0    False
1     True
2    False
3     True
4    False
dtype: bool

See the section on Flexible Comparisons.. To summarise, we have

+------------------------------+
¦    ¦ Operator   ¦ Function   ¦
¦----+------------+------------¦
¦  0 ¦ >          ¦ gt         ¦
+----+------------+------------¦
¦  1 ¦ >=         ¦ ge         ¦
+----+------------+------------¦
¦  2 ¦ <          ¦ lt         ¦
+----+------------+------------¦
¦  3 ¦ <=         ¦ le         ¦
+----+------------+------------¦
¦  4 ¦ ==         ¦ eq         ¦
+----+------------+------------¦
¦  5 ¦ !=         ¦ ne         ¦
+------------------------------+

Another option for avoiding parentheses is to use DataFrame.query (or eval):

df.query('A < 5 and B > 5')

   A  B  C
1  3  7  9
3  4  7  6

I have extensively documented query and eval in Dynamic Expression Evaluation in pandas using pd.eval().

operator.and_
Allows you to perform this operation in a functional manner. Internally calls Series.__and__ which corresponds to the bitwise operator.

import operator 

operator.and_(df['A'] < 5, df['B'] > 5)
# Same as,
# (df['A'] < 5).__and__(df['B'] > 5) 

0    False
1     True
2    False
3     True
4    False
dtype: bool

df[operator.and_(df['A'] < 5, df['B'] > 5)]

   A  B  C
1  3  7  9
3  4  7  6

You won't usually need this, but it is useful to know.

Generalizing: np.logical_and (and logical_and.reduce)
Another alternative is using np.logical_and, which also does not need parentheses grouping:

np.logical_and(df['A'] < 5, df['B'] > 5)

0    False
1     True
2    False
3     True
4    False
Name: A, dtype: bool

df[np.logical_and(df['A'] < 5, df['B'] > 5)]

   A  B  C
1  3  7  9
3  4  7  6

np.logical_and is a ufunc (Universal Functions), and most ufuncs have a reduce method. This means it is easier to generalise with logical_and if you have multiple masks to AND. For example, to AND masks m1 and m2 and m3 with &, you would have to do

m1 & m2 & m3

However, an easier option is

np.logical_and.reduce([m1, m2, m3])

This is powerful, because it lets you build on top of this with more complex logic (for example, dynamically generating masks in a list comprehension and adding all of them):

import operator

cols = ['A', 'B']
ops = [np.less, np.greater]
values = [5, 5]

m = np.logical_and.reduce([op(df[c], v) for op, c, v in zip(ops, cols, values)])
m 
# array([False,  True, False,  True, False])

df[m]
   A  B  C
1  3  7  9
3  4  7  6

1 - I know I'm harping on this point, but please bear with me. This is a very, very common beginner's mistake, and must be explained very thoroughly.


Logical OR

For the df above, say you'd like to return all rows where A == 3 or B == 7.

Overloaded Bitwise |

df['A'] == 3

0    False
1     True
2     True
3    False
4    False
Name: A, dtype: bool

df['B'] == 7

0    False
1     True
2    False
3     True
4    False
Name: B, dtype: bool

(df['A'] == 3) | (df['B'] == 7)

0    False
1     True
2     True
3     True
4    False
dtype: bool

df[(df['A'] == 3) | (df['B'] == 7)]

   A  B  C
1  3  7  9
2  3  5  2
3  4  7  6

If you haven't yet, please also read the section on Logical AND above, all caveats apply here.

Alternatively, this operation can be specified with

df[df['A'].eq(3) | df['B'].eq(7)]

   A  B  C
1  3  7  9
2  3  5  2
3  4  7  6

operator.or_
Calls Series.__or__ under the hood.

operator.or_(df['A'] == 3, df['B'] == 7)
# Same as,
# (df['A'] == 3).__or__(df['B'] == 7)

0    False
1     True
2     True
3     True
4    False
dtype: bool

df[operator.or_(df['A'] == 3, df['B'] == 7)]

   A  B  C
1  3  7  9
2  3  5  2
3  4  7  6

np.logical_or
For two conditions, use logical_or:

np.logical_or(df['A'] == 3, df['B'] == 7)

0    False
1     True
2     True
3     True
4    False
Name: A, dtype: bool

df[np.logical_or(df['A'] == 3, df['B'] == 7)]

   A  B  C
1  3  7  9
2  3  5  2
3  4  7  6

For multiple masks, use logical_or.reduce:

np.logical_or.reduce([df['A'] == 3, df['B'] == 7])
# array([False,  True,  True,  True, False])

df[np.logical_or.reduce([df['A'] == 3, df['B'] == 7])]

   A  B  C
1  3  7  9
2  3  5  2
3  4  7  6

Logical NOT

Given a mask, such as

mask = pd.Series([True, True, False])

If you need to invert every boolean value (so that the end result is [False, False, True]), then you can use any of the methods below.

Bitwise ~

~mask

0    False
1    False
2     True
dtype: bool

Again, expressions need to be parenthesised.

~(df['A'] == 3)

0     True
1    False
2    False
3     True
4     True
Name: A, dtype: bool

This internally calls

mask.__invert__()

0    False
1    False
2     True
dtype: bool

But don't use it directly.

operator.inv
Internally calls __invert__ on the Series.

operator.inv(mask)

0    False
1    False
2     True
dtype: bool

np.logical_not
This is the numpy variant.

np.logical_not(mask)

0    False
1    False
2     True
dtype: bool

Note, np.logical_and can be substituted for np.bitwise_and, logical_or with bitwise_or, and logical_not with invert.

How to get ASCII value of string in C#

You can remove the BOM using:

//Create a character to compare BOM
char byteOrderMark = (char)65279;
if (sourceString.ToCharArray()[0].Equals(byteOrderMark))
{
    targetString = sourceString.Remove(0, 1);
}

Where is the .NET Framework 4.5 directory?

.NET 4.5 is an in place replacement for 4.0 - you will find the assemblies in the 4.0 directory.

See the blogs by Rick Strahl and Scott Hanselman on this topic.

You can also find the specific versions in:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework

Keylistener in Javascript

Did you check the small Mousetrap library?

Mousetrap is a simple library for handling keyboard shortcuts in JavaScript.

Could not load file or assembly or one of its dependencies. Access is denied. The issue is random, but after it happens once, it continues

For me, the following hack worked; Go to IIS -> Application Pools -> Advance Settings -> Process Model -> Identity Changed from Built-in Account (ApplicationPoolIdentity) to Custom Account (My Domain User)

jQuery form validation on button click

Within your click handler, the mistake is the .validate() method; it only initializes the plugin, it does not validate the form.

To eliminate the need to have a submit button within the form, use .valid() to trigger a validation check...

$('#btn').on('click', function() {
    $("#form1").valid();
});

jsFiddle Demo

.validate() - to initialize the plugin (with options) once on DOM ready.

.valid() - to check validation state (boolean value) or to trigger a validation test on the form at any time.

Otherwise, if you had a type="submit" button within the form container, you would not need a special click handler and the .valid() method, as the plugin would capture that automatically.

Demo without click handler


EDIT:

You also have two issues within your HTML...

<input id="field1" type="text" class="required">
  • You don't need class="required" when declaring rules within .validate(). It's redundant and superfluous.

  • The name attribute is missing. Rules are declared within .validate() by their name. The plugin depends upon unique name attributes to keep track of the inputs.

Should be...

<input name="field1" id="field1" type="text" />

How can I get log4j to delete old rotating log files?

Logs rotate for a reason, so that you only keep so many log files around. In log4j.xml you can add this to your node:

<param name="MaxBackupIndex" value="20"/>

The value tells log4j.xml to only keep 20 rotated log files around. You can limit this to 5 if you want or even 1. If your application isn't logging that much data, and you have 20 log files spanning the last 8 months, but you only need a weeks worth of logs, then I think you need to tweak your log4j.xml "MaxBackupIndex" and "MaxFileSize" params.

Alternatively, if you are using a properties file (instead of the xml) and wish to save 15 files (for example)

log4j.appender.[appenderName].MaxBackupIndex = 15

Disable resizing of a Windows Forms form

Take a look at the FormBorderStyle property

form1.FormBorderStyle = FormBorderStyle.FixedSingle;

You may also want to remove the minimize and maximize buttons:

form1.MaximizeBox = false;
form1.MinimizeBox = false;

How to create a Multidimensional ArrayList in Java?

Here an answer for those who'd like to have preinitialized lists of lists. Needs Java 8+.

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

class Scratch {

  public static void main(String[] args) {
    int M = 4;
    int N = 3;

    // preinitialized array (== list of lists) of strings, sizes not fixed
    List<List<String>> listOfListsOfString = initializeListOfListsOfT(M, N, "-");
    System.out.println(listOfListsOfString);

    // preinitialized array (== list of lists) of int (primitive type), sizes not fixed
    List<List<Integer>> listOfListsOfInt = initializeListOfListsOfInt(M, N, 7);
    System.out.println(listOfListsOfInt);
  }

  public static <T> List<List<T>> initializeListOfListsOfT(int m, int n, T initValue) {
    return IntStream
        .range(0, m)
        .boxed()
        .map(i -> new ArrayList<T>(IntStream
            .range(0, n)
            .boxed()
            .map(j -> initValue)
            .collect(Collectors.toList()))
        )
        .collect(Collectors.toList());
  }

  public static List<List<Integer>> initializeListOfListsOfInt(int m, int n, int initValue) {
    return IntStream
        .range(0, m)
        .boxed()
        .map(i -> new ArrayList<>(IntStream
            .range(0, n)
            .map(j -> initValue)
            .boxed()
            .collect(Collectors.toList()))
        )
        .collect(Collectors.toList());
  }
}

Output:

[[-, -, -], [-, -, -], [-, -, -], [-, -, -]]
[[7, 7, 7], [7, 7, 7], [7, 7, 7], [7, 7, 7]]

Side note for those wondering about IntStream:

IntStream
    .range(0, m)
    .boxed()

is equivalent to

Stream
    .iterate(0, j -> j + 1)
    .limit(n)

What does 'foo' really mean?

The sound of the french fou, (like: amour fou) [crazy] written in english, would be foo, wouldn't it. Else furchtbar -> foobar -> foo, bar -> barfoo -> barfuß (barefoot). Just fou. A foot without teeth.

I agree with all, who mentioned it means: nothing interesting, just something, usually needed to complete a statement/expression.