Programs & Examples On #Ccl

Clozure CL (CCL) is a Common Lisp implementation.

How to download Visual Studio 2017 Community Edition for offline installation?

Here you can download visual studio 2017 initial installer:

Run it and after few minutes it will ask what components do you want to install and in the right bottom there will be two option
"Install while downloading"
"Download all, then install"

Select any option and click install.

Default property value in React component using TypeScript

Functional Component

Actually, for functional component the best practice is like below, I create a sample Spinner component:

import React from 'react';
import { ActivityIndicator } from 'react-native';
import { colors } from 'helpers/theme';
import type { FC } from 'types';

interface SpinnerProps {
  color?: string;
  size?: 'small' | 'large' | 1 | 0;
  animating?: boolean;
  hidesWhenStopped?: boolean;

const Spinner: FC<SpinnerProps> = ({
}) => (

Spinner.defaultProps = {
  animating: true,
  color: colors.primary,
  hidesWhenStopped: true,
  size: 'small',

export default Spinner;

How to set TLS version on apache HttpClient

The solution is:

SSLContext sslContext = SSLContexts.custom()

SSLConnectionSocketFactory f = new SSLConnectionSocketFactory(
    new String[]{"TLSv1", "TLSv1.1"},   

httpClient = HttpClients.custom()

This requires org.apache.httpcomponents.httpclient 4.3.x though.

org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

The following are some of the reasons for the hibernate.dialect not set issue. Most of these exceptions are shown in the startup log which is finally followed by the mentioned issue.

Example: In Spring boot app with Postgres DB

1. Check if the database is actually installed and its server is started.

  • org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
  • Connection refused: connect
  • org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]

2. Check if the database name is correctly mentioned.

  • org.postgresql.util.PSQLException: FATAL: database "foo" does not exist

    In file,

    spring.datasource.url = jdbc:postgresql://localhost:5432/foo

    but foo didn't exist. So I created the database from pgAdmin for postgres


3. Check if the host name and server port is accessible.

  • org.postgresql.util.PSQLException: Connection to localhost:5431 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
  • Connection refused: connect

4. Check if the database credentials are correct.

  • as @Pankaj mentioned
  • org.postgresql.util.PSQLException: FATAL: password authentication failed for user "postgres"

    spring.datasource.username= {DB USERNAME HERE}

    spring.datasource.password= {DB PASSWORD HERE}

There is already an object named in the database

same happened with me.. Problem was that Actually i deleted my Database table MoviesCast and made new table and problem was that my last migration was trying to induce the deleted table MoviesCast in the database. I Solved it by simply removing all the content of last migration and simply ran Up() & down() method

public override void Up()

public override void Down()

then updated the database and simply add new migration

SQL Connection Error: System.Data.SqlClient.SqlException (0x80131904)

I had the same issue.

Make sure that In SQL Server configuration --> SQL Server Services --> SQL Server Agent is enable

This solved my problem

How to resolve this System.IO.FileNotFoundException

I came across a similar situation after publishing a ClickOnce application, and one of my colleagues on a different domain reported that it fails to launch.

To find out what was going on, I added a try catch statement inside the MainWindow method as @BradleyDotNET mentioned in one comment on the original post, and then published again.

public MainWindow()
    catch (Exception exc)

Then my colleague reported to me the exception detail, and it was a missing reference of a third party framework dll file.

Added the reference and problem solved.

System.Data.SqlClient.SqlException: Login failed for user

I had similar experience and it took me time to solve the problem. Though, my own case was ASP.Net MVC Core and Core framework. Setting Trusted_Connection=False; solved my problem.

Inside appsettings.json file

"ConnectionStrings": {
    "DefaultConnection": "Server=servername; Database=databasename; User Id=userid; Password=password; Trusted_Connection=False; MultipleActiveResultSets=true",

System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll?

This is not a problem with XAML. The error message is saying that it tried to create an instance of DVRClientInterface.MainWindow and your constructor threw an exception.

You will need to look at the "Inner Exception" property to determine the underlying cause. It could be quite literally anything, but should provide direction.

example of an inner exception shown in Visual Studio

An example would be that if you are connecting to a database in the constructor for your window, and for some reason that database is unavailable, the inner exception may be a TimeoutException or a SqlException or any other exception thrown by your database code.

If you are throwing exceptions in static constructors, the exception could be generated from any class referenced by the MainWindow. Class initializers are also run, if any MainWindow fields are calling a method which may throw.

Cannot deserialize the current JSON array (e.g. [1,2,3])

You have an array, convert it to an object, something like:

data: [{"id": 3636, "is_default": true, "name": "Unit", "quantity": 1, "stock": "100000.00", "unit_cost": "0"}, {"id": 4592, "is_default": false, "name": "Bundle", "quantity": 5, "stock": "100000.00", "unit_cost": "0"}]

OWIN Security - How to Implement OAuth2 Refresh Tokens

You need to implement RefreshTokenProvider. First create class for RefreshTokenProvider ie.

public class ApplicationRefreshTokenProvider : AuthenticationTokenProvider
    public override void Create(AuthenticationTokenCreateContext context)
        // Expiration time in seconds
        int expire = 5*60;
        context.Ticket.Properties.ExpiresUtc = new DateTimeOffset(DateTime.Now.AddSeconds(expire));

    public override void Receive(AuthenticationTokenReceiveContext context)

Then add instance to OAuthOptions.

OAuthOptions = new OAuthAuthorizationServerOptions
    TokenEndpointPath = new PathString("/authenticate"),
    Provider = new ApplicationOAuthProvider(),
    AccessTokenExpireTimeSpan = TimeSpan.FromSeconds(expire),
    RefreshTokenProvider = new ApplicationRefreshTokenProvider()

"The system cannot find the file specified"

The most common reason could be the database connection string. You have to change the connection string attachDBFile=|DataDirectory|file_name.mdf. there might be problem in host name which would be (local),localhost or .\sqlexpress.

Excel VBA Run-time Error '32809' - Trying to Understand it

I have the same problem and found that this is the problem of Microsoft vulnerabilities.

It works for me when I install these update patches. You can find these patches on .

  1. If your office 2010 version is SP1, you need download and install office SP2 pack first. Update patch name is KB2687455.

  2. Install update patch KB2965240.

    This security update resolves vulnerabilities in Microsoft Office that could allow remote code execution if an attacker convinces a user to open or preview a specially crafted Microsoft Excel workbook in an affected version of Office. An attacker who successfully exploited the vulnerabilities could gain the same user rights as the current user.

  3. Install update patch KB2553154.

    A security vulnerability exists in Microsoft Office 2010 32-Bit Edition that could allow arbitrary code to run when a maliciously modified file is opened. This update resolves that vulnerability.

Win32Exception (0x80004005): The wait operation timed out

The problem you are having is the query command is taking too long. I believe that the default timeout for a query to execute is 15 seconds. You need to set the CommandTimeout (in seconds) so that it is long enough for the command to complete its execution. The "CommandTimeout" is different than the "Connection Timeout" in your connection string and must be set for each command.

In your sql Selecting Event, use the command:

e.Command.CommandTimeout = 60

for example:

Protected Sub SqlDataSource1_Selecting(sender As Object, e As System.Web.UI.WebControls.SqlDataSourceSelectingEventArgs)
    e.Command.CommandTimeout = 60
End Sub

A network-related or instance-specific error occurred while establishing a connection to SQL Server

Sql Server fire this error when your application don't have enough rights to access the database. there are several reason about this error . To fix this error you should follow the following instruction.

  1. Try to connect sql server from your server using management studio . if you use windows authentication to connect sql server then set your application pool identity to server administrator .

  2. if you use sql server authentication then check you connection string in web.config of your web application and set user id and password of sql server which allows you to log in .

  3. if your database in other server(access remote database) then first of enable remote access of sql server form sql server property from sql server management studio and enable TCP/IP form sql server configuration manager .

  4. after doing all these stuff and you still can't access the database then check firewall of server form where you are trying to access the database and add one rule in firewall to enable port of sql server(by default sql server use 1433 , to check port of sql server you need to check sql server configuration manager network protocol TCP/IP port).

  5. if your sql server is running on named instance then you need to write port number with sql serer name for example 117.312.21.21/nameofsqlserver,1433.

  6. If you are using cloud hosting like amazon aws or microsoft azure then server or instance will running behind cloud firewall so you need to enable 1433 port in cloud firewall if you have default instance or specific port for sql server for named instance.

  7. If you are using amazon RDS or SQL azure then you need to enable port from security group of that instance.

  8. If you are accessing sql server through sql server authentication mode them make sure you enabled "SQL Server and Windows Authentication Mode" sql server instance property. enter image description here

    1. Restart your sql server instance after making any changes in property as some changes will require restart.

if you further face any difficulty then you need to provide more information about your web site and sql server .

TypeScript static classes

I was searching for something similar and came accross something called the Singleton Pattern.

Reference: Singleton Pattern

I am working on a BulkLoader class to load different types of files and wanted to use the Singleton pattern for it. This way I can load files from my main application class and retrieve the loaded files easily from other classes.

Below is a simple example how you can make a score manager for a game with TypeScript and the Singleton pattern.

class SingletonClass {

private static _instance:SingletonClass = new SingletonClass();

private _score:number = 0;

constructor() {
        throw new Error("Error: Instantiation failed: Use SingletonDemo.getInstance() instead of new.");
    SingletonClass._instance = this;

public static getInstance():SingletonClass
    return SingletonClass._instance;

public setScore(value:number):void
    this._score = value;

public getScore():number
    return this._score;

public addPoints(value:number):void
    this._score += value;

public removePoints(value:number):void
    this._score -= value;
}   }

Then anywhere in your other classes you would get access to the Singleton by:

var scoreManager = SingletonClass.getInstance();
scoreManager.setScore(10); scoreManager.addPoints(1);
scoreManager.removePoints(2); console.log( scoreManager.getScore() );

SQLException: No suitable Driver Found for jdbc:oracle:thin:@//localhost:1521/orcl

For me I did enter a invalid url like : orcl only instead of jdbc:oracle:thin:@//localhost:1521/orcl


You need to replace it as WHERE clockDate = { fn CURRENT_DATE() } AND userName = 'test'. Please remove extra ")" from { fn CURRENT_DATE() })

How do you handle a "cannot instantiate abstract class" error in C++?

An abstract class cannot be instantiated by definition. In order to use this class, you must create a concrete subclass which implements all virtual functions of the class. In this case, you most likely have not implemented all the virtual functions declared in Light. This means that AmbientOccluder defaults to an abstract class. For us to further help you, you should include the details of the Light class.

How to properly stop the Thread in Java?

Sometime I will try 1000 times in my onDestroy()/contextDestroyed()

    protected void onDestroy() {
        boolean retry = true;
        int counter = 0;
        while(retry && counter<1000)
                retry = false;
                thread = null; //garbage can coll
            }catch(InterruptedException e){e.printStackTrace();}


Encrypting & Decrypting a String in C#

If you need to store a password in memory and would like to have it encrypted you should use SecureString:

For more general uses I would use a FIPS approved algorithm such as Advanced Encryption Standard, formerly known as Rijndael. See this page for an implementation example:

No connection could be made because the target machine actively refused it

With similar pattern, my rest client is calling the service API, the service called successfully when debugging, but not working on the published code. Error was: Unable to connect to the remote server.

Inner Exception: System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it serviceIP:443 at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception)

Resolution: Set the proxy in Web config.

    <defaultProxy useDefaultCredentials="true">
      <proxy proxyaddress="http://proxy_ip:portno/" usesystemdefault="True"/>

How to update UI from another thread running in another class

Thank God, Microsoft got that figured out in WPF :)

Every Control, like a progress bar, button, form, etc. has a Dispatcher on it. You can give the Dispatcher an Action that needs to be performed, and it will automatically call it on the correct thread (an Action is like a function delegate).

You can find an example here.

Of course, you'll have to have the control accessible from other classes, e.g. by making it public and handing a reference to the Window to your other class, or maybe by passing a reference only to the progress bar.

Copy struct to struct in C

Your code is correct. You can also assign one directly to the other (see Joachim Pileborg's answer).

When you later come to compare the two structs, you need to be careful to compare the structs the long way, one member at a time, instead of using memcmp; see How do you compare structs for equality in C?

Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]

I had the same exception and I was excluding javassist because of its issue with powermock. Then I was adding it again as below but it was not working:



Finally I found out that I have to remove <scope>test</scope> from javassist dependency. Hope it helps someone.

Classes cannot be accessed from outside package

public SmartSaverCals(Context context)
    this.context= context;

add public to Your my case problem solved

WAMP Server doesn't load localhost

Change the port 80 to port 8080 and restart all services and access like localhost:8080/

It will work fine.

Java: unable to find valid certification path to requested target

I was able to get it working with code only, i.e. no need to use keytool:

import org.apache.http.client.config.RequestConfig;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.ssl.SSLContexts;
import org.apache.http.conn.ssl.TrustStrategy;
import org.apache.http.conn.ssl.X509HostnameVerifier;
import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
import org.apache.http.impl.nio.client.HttpAsyncClients;
import org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager;
import org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor;
import org.apache.http.impl.nio.reactor.IOReactorConfig;
import org.apache.http.nio.conn.NoopIOSessionStrategy;
import org.apache.http.nio.conn.SchemeIOSessionStrategy;
import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;


public class Test
    private static final DynamicIntProperty MAX_TOTAL_CONNECTIONS = DynamicPropertyFactory.getInstance().getIntProperty("", 40);
    private static final DynamicIntProperty ROUTE_CONNECTIONS = DynamicPropertyFactory.getInstance().getIntProperty("", 40);
    private static final DynamicIntProperty CONNECT_TIMEOUT = DynamicPropertyFactory.getInstance().getIntProperty("X.connect.timeout", 60000);
    private static final DynamicIntProperty SOCKET_TIMEOUT = DynamicPropertyFactory.getInstance().getIntProperty("X.socket.timeout", -1);
    private static final DynamicIntProperty CONNECTION_REQUEST_TIMEOUT = DynamicPropertyFactory.getInstance().getIntProperty("X.connectionrequest.timeout", 60000);
    private static final DynamicBooleanProperty STALE_CONNECTION_CHECK = DynamicPropertyFactory.getInstance().getBooleanProperty("X.checkconnection", true);

    public static void main(String[] args) throws Exception

        SSLContext sslcontext = SSLContexts.custom()
                .loadTrustMaterial(null, new TrustStrategy()
                    public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException
                        return true;
        SSLIOSessionStrategy sslSessionStrategy = new SSLIOSessionStrategy(sslcontext, new AllowAll());

        Registry<SchemeIOSessionStrategy> sessionStrategyRegistry = RegistryBuilder.<SchemeIOSessionStrategy>create()
                .register("http", NoopIOSessionStrategy.INSTANCE)
                .register("https", sslSessionStrategy)

        DefaultConnectingIOReactor ioReactor = new DefaultConnectingIOReactor(IOReactorConfig.DEFAULT);
        PoolingNHttpClientConnectionManager connectionManager = new PoolingNHttpClientConnectionManager(ioReactor, sessionStrategyRegistry);

        RequestConfig requestConfig = RequestConfig.custom()

        CloseableHttpAsyncClient httpClient = HttpAsyncClients.custom()


        // use httpClient...

    private static class AllowAll implements X509HostnameVerifier
        public void verify(String s, SSLSocket sslSocket) throws IOException

        public void verify(String s, X509Certificate x509Certificate) throws SSLException {}

        public void verify(String s, String[] strings, String[] strings2) throws SSLException

        public boolean verify(String s, SSLSession sslSession)
            return true;

How do I force make/GCC to show me the commands?

Depending on your automake version, you can also use this:



Note: I added this answer since V=1 did not work for me.

Apache HttpClient 4.0.3 - how do I set cookie with sessionID for POST request?

I am so glad to solve this problem:

HttpPost httppost = new HttpPost(postData); 
CookieStore cookieStore = new BasicCookieStore(); 
BasicClientCookie cookie = new BasicClientCookie("JSESSIONID", getSessionId());

//cookie.setDomain("your domain");

response = client.execute(httppost); 

So Easy!

How to dynamically create a class?

Runtime Code Generation with JVM and CLR - Peter Sestoft

Work for persons that are really interested in this type of programming.

My tip for You is that if You declare something try to avoid string, so if You have class Field it is better to use class System.Type to store the field type than a string. And for the sake of best solutions instead of creation new classes try to use those that has been created FiledInfo instead of creation new.

Python base64 data decode

base64 encode/decode example:

import base64

mystr = 'O João mordeu o cão!'

# Encode
mystr_encoded = base64.b64encode(mystr.encode('utf-8'))
# b'TyBKb8OjbyBtb3JkZXUgbyBjw6NvIQ=='

# Decode
mystr_encoded = base64.b64decode(mystr_encoded).decode('utf-8')
# 'O João mordeu o cão!'

Get generic type of class at runtime

I did the same as @Moesio Above but in Kotlin it could be done this way:

class A<T : SomeClass>() {

    var someClassType : T

    this.someClassType = (javaClass.genericSuperclass as ParameterizedType).actualTypeArguments[0] as Class<T>


Java: Multiple class declarations in one file

1.Is there a tidy name for this technique (analogous to inner, nested, anonymous)?

Multi-class single-file demo.

2.The JLS says the system may enforce the restriction that these secondary classes can't be referred to by code in other compilation units of the package, e.g., they can't be treated as package-private. Is that really something that changes between Java implementations?

I'm not aware of any which don't have that restriction - all the file based compilers won't allow you to refer to source code classes in files which are not named the same as the class name. ( if you compile a multi-class file, and put the classes on the class path, then any compiler will find them )

MySQL Install: ERROR: Failed to build gem native extension

In order to resolve

Gem::Ext::BuildError: ERROR: Failed to build gem native extension error for mysql2,

I think libmysql-ruby got changed with ruby-mysql

Simply try with following commands,

sudo apt-get install ruby-mysql

& then

sudo apt-get install libmysqlclient-dev

Check if a class is derived from a generic class

Added to @jaredpar's answer, here's what I use to check for interfaces:

public static bool IsImplementerOfRawGeneric(this Type type, Type toCheck)
    if (toCheck.GetTypeInfo().IsClass)
        return false;

    return type.GetInterfaces().Any(interfaceType =>
        var current = interfaceType.GetTypeInfo().IsGenericType ?
                    interfaceType.GetGenericTypeDefinition() : interfaceType;
        return current == toCheck;

public static bool IsSubTypeOfRawGeneric(this Type type, Type toCheck)
    return type.IsInterface ?
          IsImplementerOfRawGeneric(type, toCheck)
        : IsSubclassOfRawGeneric(type, toCheck);


Console.WriteLine(typeof(IList<>).IsSubTypeOfRawGeneric(typeof(IList<int>))); // true

How to properly and completely close/reset a TcpClient connection?

You have to close the stream before closing the connection:


Closing the client does not close the stream.

Equivalent of typedef in C#

No, there's no true equivalent of typedef. You can use 'using' directives within one file, e.g.

using CustomerList = System.Collections.Generic.List<Customer>;

but that will only impact that source file. In C and C++, my experience is that typedef is usually used within .h files which are included widely - so a single typedef can be used over a whole project. That ability does not exist in C#, because there's no #include functionality in C# that would allow you to include the using directives from one file in another.

Fortunately, the example you give does have a fix - implicit method group conversion. You can change your event subscription line to just:

gcInt.MyEvent += gcInt_MyEvent;


What are some resources for getting started in operating system development?

The x86 JS simulator and ARM simulator can also be very useful to understand how different pieces hardware works and make tests without exiting your favourite browser.

How do I SET the GOPATH environment variable on Ubuntu? What file must I edit?

My go environment looked similar to yours.

$go env
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"

I resolved it with setting GOPATH to /usr/lib/go. Try it out.

export GOPATH=/usr/lib/go
export PATH=$PATH:$GOPATH/bin

Laravel - Pass more than one variable to view

Use compact

function view($view)
    $ms = Person::where('name', '=', 'Foo Bar')->first();

    $persons = Person::order_by('list_order', 'ASC')->get();
    return View::make('users', compact('ms','persons'));

jquery 3.0 url.indexOf error

Jquery 3.0 has some breaking changes that remove certain methods due to conflicts. Your error is most likely due to one of these changes such as the removal of the .load() event.

Read more in the jQuery Core 3.0 Upgrade Guide

To fix this you either need to rewrite the code to be compatible with Jquery 3.0 or else you can use the JQuery Migrate plugin which restores the deprecated and/or removed APIs and behaviours.

How to show x and y axes in a MATLAB graph?

The poor man's solution is to simply graph the lines x=0 and y=0. You can adjust the thickness and color of the lines to differentiate them from the graph.

How to filter Android logcat by application?

On Linux/Un*X/Cygwin you can get list of all tags in project (with appended :V after each) with this command (split because readability):

$ git grep 'String\s\+TAG\s*=\s*' |  \
  perl -ne 's/.*String\s+TAG\s*=\s*"?([^".]+).*;.*/$1:V/g && print ' | \
  sort | xargs
AccelerometerListener:V ADNList:V Ashared:V AudioDialog:V BitmapUtils:V # ...

It covers tags defined both ways of defining tags:

private static final String TAG = "AudioDialog";
private static final String TAG = SipProfileDb.class.getSimpleName();

And then just use it for adb logcat.

Update index after sorting data-frame

df.sort() is deprecated, use df.sort_values(...):

Then follow joris' answer by doing df.reset_index(drop=True)

Git for beginners: The definitive practical guide

Git Magic is all you'll ever need. Guaranteed or your money back!

Adding a newline character within a cell (CSV)

I struggled with this as well but heres the solution. If you add " before and at the end of the csv string you are trying to display, it will consolidate them into 1 cell while honoring new line.

csvString += "\""+"Date Generated: \n" ; 
csvString += "Doctor: " + "\n"+"\"" + "\n"; 

CSS media queries: max-width OR max-height

yes, using and, like:

@media screen and (max-width: 800px), 
       screen and (max-height: 600px) {

How to find the installed pandas version

Check pandas.__version__:

In [76]: import pandas as pd

In [77]: pd.__version__
Out[77]: '0.12.0-933-g281dc4e'

Pandas also provides a utility function, pd.show_versions(), which reports the version of its dependencies as well:

In [53]: pd.show_versions(as_json=False)

commit: None
python-bits: 64
OS: Linux
OS-release: 3.13.0-45-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None

pandas: 0.15.2-113-g5531341
nose: 1.3.1
Cython: 0.21.1
numpy: 1.8.2
IPython: 2.0.0-dev
sphinx: 1.2.2
patsy: 0.3.0
dateutil: 1.5
pytz: 2012c
bottleneck: None
tables: 3.1.1
numexpr: 2.2.2
matplotlib: 1.4.2
openpyxl: None
xlrd: 0.9.3
xlwt: 0.7.5
xlsxwriter: None
lxml: 3.3.3
bs4: 4.3.2
html5lib: 0.999
httplib2: 0.8
apiclient: None
rpy2: 2.5.5
sqlalchemy: 0.9.8
pymysql: None
psycopg2: 2.4.5 (dt dec mx pq3 ext)

Programmatically add new column to DataGridView

Keep it simple

dataGridView1.Columns.Add("newColumnName", "Column Name in Text");

To add rows

dataGridView1.Rows.Add("Value for column#1"); // [,"column 2",...]

Trying to start a service on boot on Android

After trying all of mentioned answers and tricks, I finally find why the code is not work in my phone. Some Android phones like "Huawei Honor 3C Android 4.2.2" have a Statup Manager menu in their settings and your app must be checked in the list. :)

Dealing with nginx 400 "The plain HTTP request was sent to HTTPS port" error

The error says it all actually. Your configuration tells Nginx to listen on port 80 (HTTP) and use SSL. When you point your browser to http://localhost, it tries to connect via HTTP. Since Nginx expects SSL, it complains with the error.

The workaround is very simple. You need two server sections:

server {
  listen 80;

  // other directives...

server {
  listen 443;

  ssl on;
  // SSL directives...

  // other directives...

What is the difference between CMD and ENTRYPOINT in a Dockerfile?

The accepted answer is fabulous in explaining the history. I find this table explain it very well from official doc on 'how CMD and ENTRYPOINT interact': enter image description here

ASP.NET MVC Yes/No Radio Buttons with Strongly Bound Model MVC

The second parameter is selected, so use the ! to select the no value when the boolean is false.

<%= Html.RadioButton("blah", !Model.blah) %> Yes 
<%= Html.RadioButton("blah", Model.blah) %> No 

Build project into a JAR automatically in Eclipse

Creating a builder launcher is an issue since 2 projects cannot have the same external tool build name. Each name has to be unique. I am currently facing this issue to automate my build and copy the JAR to an external location.

I am using IBM's Zip Builder, but that is just a help but not doing the real.

People can try using IBM ZIP Creation plugin.

How do I navigate to another page when PHP script is done?

if ($done)
    header("Location: /url/to/the/other/page");

How do I fix a NoSuchMethodError?

If your file name is different than the class name which contain main method then it may be the possibility that this error may cause.

Backup a single table with its data from a database in sql server 2008

To get a copy in a file on the local file-system, this rickety utility from the Windows start button menu worked: "C:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn\DTSWizard.exe"

Boolean Field in Oracle

A working example to implement the accepted answer by adding a "Boolean" column to an existing table in an oracle database (using number type):

ALTER TABLE my_table_name ADD (
my_new_boolean_column number(1) DEFAULT 0 NOT NULL
CONSTRAINT my_new_boolean_column CHECK (my_new_boolean_column in (1,0))

This creates a new column in my_table_name called my_new_boolean_column with default values of 0. The column will not accept NULL values and restricts the accepted values to either 0 or 1.

How to get the html of a div on another page with jQuery ajax?

  success: function(data){

This console log gets an array like object: [meta, title, ,], very strange

You can use JavaScript:

var doc = document.documentElement.cloneNode()
doc.innerHTML = data
$content = $(doc.querySelector('#content'))

Capturing mobile phone traffic on Wireshark

Another option which has not been suggested here is to run the app you want to monitor in the Android emulator from the Android SDK. You can then easily capture the traffic with wireshark on the same machine.

This was the easiest option for me.

How to delete directory content in Java?

To delete folder having files, no need of loops or recursive search. You can directly use:

FileUtils.deleteDirectory(<File object of directory>);

This function will directory delete the folder and all files in it.

How do I remove javascript validation from my eclipse project?

Turn off the JavaScript Validator in the "Builders" config for your project:

  1. Right click your project
  2. Select Properties -> Builders
  3. Uncheck the "JavaScript Validator"

Then either restart your Eclipse or/and rename the .js to something like .js_ then back again.

How to prevent Browser cache for php site

I had problem with caching my css files. Setting headers in PHP didn't help me (perhaps because the headers would need to be set in the stylesheet file instead of the page linking to it?).

I found the solution on this page:

The solution:

Append timestamp as the query part of the URI for the linked file.
(Can be used for css, js, images etc.)

For development:

<link rel="stylesheet" href="style.css?<?php echo date('Y-m-d_H:i:s'); ?>">

For production (where caching is mostly a good thing):

<link rel="stylesheet" type="text/css" href="style.css?version=3.2">
(and rewrite manually when it is required)

Or combination of these two:

    define( "DEBUGGING", true ); // or false in production enviroment
<!-- ... -->
<link rel="stylesheet" type="text/css" href="style.css?version=3.2<?php echo (DEBUGGING) ? date('_Y-m-d_H:i:s') : ""; ?>">


Or prettier combination of those two:

    // Init
    define( "DEBUGGING", true ); // or false in production enviroment
    // Functions
    function get_cache_prevent_string( $always = false ) {
        return (DEBUGGING || $always) ? date('_Y-m-d_H:i:s') : "";
<!-- ... -->
<link rel="stylesheet" type="text/css" href="style.css?version=3.2<?php echo get_cache_prevent_string(); ?>">

How do you remove the title text from the Android ActionBar?

Use the following:


Ant if else condition?

Since ant 1.9.1 you can use a if:set condition :

PowerShell: Store Entire Text File Contents in Variable

To get the entire contents of a file:

$content = [IO.File]::ReadAllText(".\test.txt")

Number of lines:



(gc .\test.ps1).length

Sort of hackish to include trailing empty line:


How to make an array of arrays in Java

While there are two excellent answers telling you how to do it, I feel that another answer is missing: In most cases you shouldn't do it at all.

Arrays are cumbersome, in most cases you are better off using the Collection API.

With Collections, you can add and remove elements and there are specialized Collections for different functionality (index-based lookup, sorting, uniqueness, FIFO-access, concurrency etc.).

While it's of course good and important to know about Arrays and their usage, in most cases using Collections makes APIs a lot more manageable (which is why new libraries like Google Guava hardly use Arrays at all).

So, for your scenario, I'd prefer a List of Lists, and I'd create it using Guava:

List<List<String>> listOfLists = Lists.newArrayList();

How to fit Windows Form to any screen resolution?

You can simply set the window state

this.WindowState = System.Windows.Forms.FormWindowState.Maximized;

Starting ssh-agent on Windows 10 fails: "unable to start ssh-agent service, error :1058"

I get the same error in Cygwin. I had to install the openssh package in Cygwin Setup.

(The strange thing was that all ssh-* commands were valid, (bash could execute as program) but the openssh package wasn't installed.)

how to pass variable from shell script to sqlplus

You appear to have a heredoc containing a single SQL*Plus command, though it doesn't look right as noted in the comments. You can either pass a value in the heredoc:

sqlplus -S user/pass@localhost << EOF
@/opt/D2RQ/file.sql BUILDING

or if BUILDING is $2 in your script:

sqlplus -S user/pass@localhost << EOF
@/opt/D2RQ/file.sql $2

If your file.sql had an exit at the end then it would be even simpler as you wouldn't need the heredoc:

sqlplus -S user/pass@localhost @/opt/D2RQ/file.sql $2

In your SQL you can then refer to the position parameters using substitution variables:


The &1 will be replaced with the first value passed to the SQL script, BUILDING; because that is a string it still needs to be enclosed in quotes. You might want to set verify off to stop if showing you the substitutions in the output.

You can pass multiple values, and refer to them sequentially just as you would positional parameters in a shell script - the first passed parameter is &1, the second is &2, etc. You can use substitution variables anywhere in the SQL script, so they can be used as column aliases with no problem - you just have to be careful adding an extra parameter that you either add it to the end of the list (which makes the numbering out of order in the script, potentially) or adjust everything to match:

sqlplus -S user/pass@localhost << EOF
@/opt/D2RQ/file.sql total_count BUILDING


sqlplus -S user/pass@localhost << EOF
@/opt/D2RQ/file.sql total_count $2

If total_count is being passed to your shell script then just use its positional parameter, $4 or whatever. And your SQL would then be:

        ?s rdf:type :ProcessSpec .
        ?s ?p ?o

If you pass a lot of values you may find it clearer to use the positional parameters to define named parameters, so any ordering issues are all dealt with at the start of the script, where they are easier to maintain:

define MY_ALIAS = &1
define MY_MODEL = &2

        ?s rdf:type :ProcessSpec .
        ?s ?p ?o

From your separate question, maybe you just wanted:

        ?s rdf:type :ProcessSpec .
        ?s ?p ?o

... so the alias will be the same value you're querying on (the value in $2, or BUILDING in the original part of the answer). You can refer to a substitution variable as many times as you want.

That might not be easy to use if you're running it multiple times, as it will appear as a header above the count value in each bit of output. Maybe this would be more parsable later:


If you set pages 0 and set heading off, your repeated calls might appear in a neat list. You might also need to set tab off and possibly use rpad('&1', 20) or similar to make that column always the same width. Or get the results as CSV with:

select '&1' ||','|| COUNT(*)

Depends what you're using the results for...

Calling a function of a module by using its name (a string)

The best answer according to the Python programming FAQ would be:

functions = {'myfoo':}

mystring = 'myfoo'
if mystring in functions:

The primary advantage of this technique is that the strings do not need to match the names of the functions. This is also the primary technique used to emulate a case construct

How to convert string into float in JavaScript?

@GusDeCool or anyone else trying to replace more than one thousands separators, one way to do it is a regex global replace: /foo/g. Just remember that . is a metacharacter, so you have to escape it or put it in brackets (\. or [.]). Here's one option:

var str = '6.000.000';

Node.js getaddrinfo ENOTFOUND

I got this issue resolved by removing non-desirable characters from the password for the connection. For example, I had these characters: <##% and it caused the problem (most probably hash tag was the root cause of the problem).

Proper way to declare custom exceptions in modern Python?

see how exceptions work by default if one vs more attributes are used (tracebacks omitted):

>>> raise Exception('bad thing happened')
Exception: bad thing happened

>>> raise Exception('bad thing happened', 'code is broken')
Exception: ('bad thing happened', 'code is broken')

so you might want to have a sort of "exception template", working as an exception itself, in a compatible way:

>>> nastyerr = NastyError('bad thing happened')
>>> raise nastyerr
NastyError: bad thing happened

>>> raise nastyerr()
NastyError: bad thing happened

>>> raise nastyerr('code is broken')
NastyError: ('bad thing happened', 'code is broken')

this can be done easily with this subclass

class ExceptionTemplate(Exception):
    def __call__(self, *args):
        return self.__class__(*(self.args + args))
# ...
class NastyError(ExceptionTemplate): pass

and if you don't like that default tuple-like representation, just add __str__ method to the ExceptionTemplate class, like:

    # ...
    def __str__(self):
        return ': '.join(self.args)

and you'll have

>>> raise nastyerr('code is broken')
NastyError: bad thing happened: code is broken

Unable to start the mysql server in ubuntu

I think this is because you are using client software and not the server.

  • mysql is client
  • mysqld is the server

Try: sudo service mysqld start

To check that service is running use: ps -ef | grep mysql | grep -v grep.


sudo apt-get purge mysql-server
sudo apt-get autoremove
sudo apt-get autoclean


sudo apt-get update
sudo apt-get install mysql-server

Backup entire folder before doing this:

sudo rm /etc/apt/apt.conf.d/50unattended-upgrades*
sudo apt-get update
sudo apt-get upgrade

Multiple condition in single IF statement

Yes that is valid syntax but it may well not do what you want.

Execution will continue after your RAISERROR except if you add a RETURN. So you will need to add a block with BEGIN ... END to hold the two statements.

Also I'm not sure why you plumped for severity 15. That usually indicates a syntax error.

Finally I'd simplify the conditions using IN

CREATE PROCEDURE [dbo].[AddApplicationUser] (@TenantId BIGINT,
                                            @UserType TINYINT,
                                            @UserName NVARCHAR(100),
                                            @Password NVARCHAR(100))
      IF ( @TenantId IS NULL
           AND @UserType IN ( 0, 1 ) )
            RAISERROR('The value for @TenantID should not be null',15,1);


How to merge a specific commit in Git

You can use git cherry-pick to apply a single commit by itself to your current branch.

Example: git cherry-pick d42c389f

frequent issues arising in android view, Error parsing XML: unbound prefix

A couple of reasons that this can happen:

1) You see this error with an incorrect namespace, or a typo in the attribute. Like 'xmlns' is wrong, it should be xmlns:android

2) First node needs to contain: xmlns:android=""

3) If you are integrating AdMob, check custom parameters like ads:adSize, you need


4) If you are using LinearLayout you might have to define tools:


How to use putExtra() and getExtra() for string data

Put String in Intent Object

  Intent intent = new Intent(FirstActivity.this,NextAcitivity.class);

NextAcitvity in onCreate method get String

String my_string=getIntent().getStringExtra("key");

that is easy and short method

How to convert an Image to base64 string in java?

The problem is that you are returning the toString() of the call to Base64.encodeBase64(bytes) which returns a byte array. So what you get in the end is the default string representation of a byte array, which corresponds to the output you get.

Instead, you should do:

encodedfile = new String(Base64.encodeBase64(bytes), "UTF-8");

How can I create a copy of an object in Python?

How can I create a copy of an object in Python?

So, if I change values of the fields of the new object, the old object should not be affected by that.

You mean a mutable object then.

In Python 3, lists get a copy method (in 2, you'd use a slice to make a copy):

>>> a_list = list('abc')
>>> a_copy_of_a_list = a_list.copy()
>>> a_copy_of_a_list is a_list
>>> a_copy_of_a_list == a_list

Shallow Copies

Shallow copies are just copies of the outermost container.

list.copy is a shallow copy:

>>> list_of_dict_of_set = [{'foo': set('abc')}]
>>> lodos_copy = list_of_dict_of_set.copy()
>>> lodos_copy[0]['foo'].pop()
>>> lodos_copy
[{'foo': {'b', 'a'}}]
>>> list_of_dict_of_set
[{'foo': {'b', 'a'}}]

You don't get a copy of the interior objects. They're the same object - so when they're mutated, the change shows up in both containers.

Deep copies

Deep copies are recursive copies of each interior object.

>>> lodos_deep_copy = copy.deepcopy(list_of_dict_of_set)
>>> lodos_deep_copy[0]['foo'].add('c')
>>> lodos_deep_copy
[{'foo': {'c', 'b', 'a'}}]
>>> list_of_dict_of_set
[{'foo': {'b', 'a'}}]

Changes are not reflected in the original, only in the copy.

Immutable objects

Immutable objects do not usually need to be copied. In fact, if you try to, Python will just give you the original object:

>>> a_tuple = tuple('abc')
>>> tuple_copy_attempt = a_tuple.copy()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'copy'

Tuples don't even have a copy method, so let's try it with a slice:

>>> tuple_copy_attempt = a_tuple[:]

But we see it's the same object:

>>> tuple_copy_attempt is a_tuple

Similarly for strings:

>>> s = 'abc'
>>> s0 = s[:]
>>> s == s0
>>> s is s0

and for frozensets, even though they have a copy method:

>>> a_frozenset = frozenset('abc')
>>> frozenset_copy_attempt = a_frozenset.copy()
>>> frozenset_copy_attempt is a_frozenset

When to copy immutable objects

Immutable objects should be copied if you need a mutable interior object copied.

>>> tuple_of_list = [],
>>> copy_of_tuple_of_list = tuple_of_list[:]
>>> copy_of_tuple_of_list[0].append('a')
>>> copy_of_tuple_of_list
>>> tuple_of_list
>>> deepcopy_of_tuple_of_list = copy.deepcopy(tuple_of_list)
>>> deepcopy_of_tuple_of_list[0].append('b')
>>> deepcopy_of_tuple_of_list
(['a', 'b'],)
>>> tuple_of_list

As we can see, when the interior object of the copy is mutated, the original does not change.

Custom Objects

Custom objects usually store data in a __dict__ attribute or in __slots__ (a tuple-like memory structure.)

To make a copyable object, define __copy__ (for shallow copies) and/or __deepcopy__ (for deep copies).

from copy import copy, deepcopy

class Copyable:
    __slots__ = 'a', '__dict__'
    def __init__(self, a, b):
        self.a, self.b = a, b
    def __copy__(self):
        return type(self)(self.a, self.b)
    def __deepcopy__(self, memo): # memo is a dict of id's to copies
        id_self = id(self)        # memoization avoids unnecesary recursion
        _copy = memo.get(id_self)
        if _copy is None:
            _copy = type(self)(
                deepcopy(self.a, memo), 
                deepcopy(self.b, memo))
            memo[id_self] = _copy 
        return _copy

Note that deepcopy keeps a memoization dictionary of id(original) (or identity numbers) to copies. To enjoy good behavior with recursive data structures, make sure you haven't already made a copy, and if you have, return that.

So let's make an object:

>>> c1 = Copyable(1, [2])

And copy makes a shallow copy:

>>> c2 = copy(c1)
>>> c1 is c2
>>> c2.b.append(3)
>>> c1.b
[2, 3]

And deepcopy now makes a deep copy:

>>> c3 = deepcopy(c1)
>>> c3.b.append(4)
>>> c1.b
[2, 3]

Checking if jquery is loaded using Javascript

Just a small modification that might actually solve the problem:

window.onload = function() {
   if (window.jQuery) {  
       // jQuery is loaded  
   } else {

Instead of $(document).Ready(function() use window.onload = function().

Android View shadow

This is may be late but for those who are still looking for answer for this I found a project on git hub and this is the only one that actually fit my needs. android-materialshadowninepatch

Just add this line on your build.gradle dependency

compile ''

cheers. thumbs up for the creator ! happycodings

Unsetting array values in a foreach loop

You can use the index of the array element to remove it from the array, the next time you use the $list variable, you will see that the array is changed.

Try something like this

foreach($list as $itemIndex => &$item) {

   if($item['status'] === false) {


Python: Maximum recursion depth exceeded

You can increment the stack depth allowed - with this, deeper recursive calls will be possible, like this:

import sys
sys.setrecursionlimit(10000) # 10000 is an example, try with different values

... But I'd advise you to first try to optimize your code, for instance, using iteration instead of recursion.

WCF Service , how to increase the timeout?

In your binding configuration, there are four timeout values you can tweak:

    <binding name="IncreasedTimeout"

The most important is the sendTimeout, which says how long the client will wait for a response from your WCF service. You can specify hours:minutes:seconds in your settings - in my sample, I set the timeout to 25 minutes.

The openTimeout as the name implies is the amount of time you're willing to wait when you open the connection to your WCF service. Similarly, the closeTimeout is the amount of time when you close the connection (dispose the client proxy) that you'll wait before an exception is thrown.

The receiveTimeout is a bit like a mirror for the sendTimeout - while the send timeout is the amount of time you'll wait for a response from the server, the receiveTimeout is the amount of time you'll give you client to receive and process the response from the server.

In case you're send back and forth "normal" messages, both can be pretty short - especially the receiveTimeout, since receiving a SOAP message, decrypting, checking and deserializing it should take almost no time. The story is different with streaming - in that case, you might need more time on the client to actually complete the "download" of the stream you get back from the server.

There's also openTimeout, receiveTimeout, and closeTimeout. The MSDN docs on binding gives you more information on what these are for.

To get a serious grip on all the intricasies of WCF, I would strongly recommend you purchase the "Learning WCF" book by Michele Leroux Bustamante:

Learning WCF,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA240_SH20_OU01_.jpg

and you also spend some time watching her 15-part "WCF Top to Bottom" screencast series - highly recommended!

For more advanced topics I recommend that you check out Juwal Lowy's Programming WCF Services book.

Programming WCF,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA240_SH20_OU01_.jpg

Forcing anti-aliasing using css: Is this a myth?

Oh yes you can:

-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
font-smoothing: antialiased;

Source for Firefox, thanks Justin for the heads up.

MongoDB via Mongoose JS - What is findByID?

If the schema of id is not of type ObjectId you cannot operate with function : findbyId()

What is a magic number, and why is it bad?

What about return variables?

I specially find it challenging when implementing stored procedures.

Imagine the next stored procedure (wrong syntax, I know, just to show an example):

int procGetIdCompanyByName(string companyName);

It return the Id of the company if it exists in a particular table. Otherwise, it returns -1. Somehow it's a magic number. Some of the recommendations I've read so far says that I'll really have to do design somthing like that:

int procGetIdCompanyByName(string companyName, bool existsCompany);

By the way, what should it return if the company does not exists? Ok: it will set existesCompany as false, but also will return -1.

Antoher option is to make two separate functions:

bool procCompanyExists(string companyName);
int procGetIdCompanyByName(string companyName);

So a pre-condition for the second stored procedure is that company exists.

But i'm afraid of concurrency, because in this system, a company can be created by another user.

The bottom line by the way is: what do you think about using that kind of "magic numbers" that are relatively known and safe to tell that something is unsuccessful or that something does not exists?

A Parser-blocking, cross-origin script is invoked via document.write - how to circumvent it?

According to Google Developers article, you can:

FIX CSS <!--[if lt IE 8]> in IE

<!--[if lt IE 8]><![endif]-->

The lt in the above statement means less than, so 'if less than IE 8'.

For all versions of IE you can just use

<!--[if IE]><![endif]-->

or for all versions above ie 6 for example.

<!--[if gt IE 6]><![endif]-->

Where gt is 'greater than'

If you would like to write specific styles for versions below and including IE8 you can write

<!--[if lte IE 8]><![endif]-->

where lte is 'less than and equal' to

Have Excel formulas that return 0, make the result blank

There is a very simple answer to this messy problem--the SUBSTITUTE function. In your example above:


Can be rewritten as follows:

=SUBSTITUTE((1/1/INDEX(A,B,C), " ", "")

How does @synchronized lock/unlock in Objective-C?

Apple's implementation of @synchronized is open source and it can be found here. Mike ash wrote two really interesting post about this subject:

In a nutshell it has a table that maps object pointers (using their memory addresses as keys) to pthread_mutex_t locks, which are locked and unlocked as needed.

Best way to create a simple python web service

Life is simple if you get a good web framework. Web services in Django are easy. Define your model, write view functions that return your CSV documents. Skip the templates.

How do I push a local repo to Bitbucket using SourceTree without creating a repo on bitbucket first?

Actually there is a more simple solution (only on Mac version). Just four steps:

  1. Right click on the repository and select "Publish to remote..."

SourceTree Publish to Remote Screeshot

  1. Next window will ask you were to publish (github, bitbucket, etc), and then you are done.
  2. Link the remote repository
  3. Push

The APK file does not exist on disk

For Unix like users (Linux/MacOs X), instead of removing ~/.gradle/caches/, in command line do :

$ cd path_to_you_project
$ touch build.gradle

Then ask Android Studio to build APK, it will reset gradle cache itself.

Store List to session

Try this..

    List<Cat> cats = new List<Cat>
        new Cat(){ Name = "Sylvester", Age=8 },
        new Cat(){ Name = "Whiskers", Age=2 },
        new Cat(){ Name = "Sasha", Age=14 }
    Session["data"] = cats;
    foreach (Cat c in cats)
        System.Diagnostics.Debug.WriteLine("Cats>>" + c.Name);     //DEBUGGG

Eliminating NAs from a ggplot

Additionally, adding na.rm= TRUE to your geom_bar() will work.

ggplot(data = MyData,aes(x= the_variable, fill=the_variable, na.rm = TRUE)) + 
   geom_bar(stat="bin", na.rm = TRUE)

I ran into this issue with a loop in a time series and this fixed it. The missing data is removed and the results are otherwise uneffected.

CSS position absolute full width problem

I don't know if this what you want but try to remove overflow: hidden from #wrap

Create SQLite database in android

Better example is here

 try {
   myDB = this.openOrCreateDatabase("DatabaseName", MODE_PRIVATE, null);

   /* Create a Table in the Database. */
     + TableName
     + " (Field1 VARCHAR, Field2 INT(3));");

   /* Insert data to a Table*/
   myDB.execSQL("INSERT INTO "
     + TableName
     + " (Field1, Field2)"
     + " VALUES ('Saranga', 22);");

   /*retrieve data from database */
   Cursor c = myDB.rawQuery("SELECT * FROM " + TableName , null);

   int Column1 = c.getColumnIndex("Field1");
   int Column2 = c.getColumnIndex("Field2");

   // Check if our result was valid.
   if (c != null) {
    // Loop through all Results
    do {
     String Name = c.getString(Column1);
     int Age = c.getInt(Column2);
     Data =Data +Name+"/"+Age+"\n";

How to fix Python Numpy/Pandas installation?

I had the same problem and, in my case, the problem was that python was looking for packages in some ordered locations, first of all the default computer one where default old packages are.

To check what your python is looking for you can do:

>>> import sys
>>> print '\n'.join(sys.path)

This was outputting the directory '/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python' before pip or brew or port folders.

The simple solution is:

export PYTHONPATH="/Library/Python/2.7/site-packages:$PYTHONPATH"

This worked well for me, I advise you to add this line to your home bash_profile file for the next time. Remember that sys.path is built using the current working directory, followed by the directories in the PYTHONPATH environment variable. Then there are the installation-dependent default dirs.

invalid types 'int[int]' for array subscript

You are subscripting a three-dimensional array myArray[10][10][10] four times myArray[i][t][x][y]. You will probably need to add another dimension to your array. Also consider a container like Boost.MultiArray, though that's probably over your head at this point.

Viewing localhost website from mobile device

In additional you should disable your antivirus or manage it to open 80 port on your system.

Android basics: running code in the UI thread

I like the one from HPP comment, it can be used anywhere without any parameter:

new Handler(Looper.getMainLooper()).post(new Runnable() {
    public void run() {
        Log.d("UI thread", "I am the UI thread");

Publish to IIS, setting Environment Variable

I have created a repository for publishing IIS with the environment configuration in Web.config.

  • Setup
    • Get the sections from .csproj and .user.csproj files into your project files.
    • Get the MyAspNetEnvironment.props, web.development.config and web.production.config files.
  • Configuration
    • Change the value of ASPNETCORE_ENVIRONMENT property in user.csproj relevantly.

How do I push a new local branch to a remote Git repository and track it too?

I think this is the simplest alias, add to your ~/.gitconfig

  publish-branch = !git push -u origin $(git rev-parse --abbrev-ref HEAD)

You just run

git publish-branch

and... it publishes the branch

Execute Immediate within a stored procedure keeps giving insufficient priviliges error

You should use this example with AUTHID CURRENT_USER :

   SEQ_NAME       VARCHAR2 (100);
   cur_id         NUMBER;



      -- ELSE
        FROM DUAL;

      cur_id := DBMS_SQL.OPEN_CURSOR;
      DBMS_SQL.parse (cur_id, FINAL_QUERY, DBMS_SQL.v7);
      DBMS_SQL.CLOSE_CURSOR (cur_id);

   END IF;


How to get records randomly from the oracle database?

Here's how to pick a random sample out of each group:


I'm not sure how efficient it is, but if you have a lot of categories and sub-categories, this seems to do the job nicely.

Real mouse position in canvas

Refer this question: The mouseEvent.offsetX I am getting is much larger than actual canvas size .I have given a function there which will exactly suit in your situation

SQL Error: ORA-12899: value too large for column

This answer still comes up high in the list for ORA-12899 and lot of non helpful comments above, even if they are old. The most helpful comment was #4 for any professional trying to find out why they are getting this when loading data.

Some characters are more than 1 byte in length, especially true on SQL Server. And what might fit in a varchar(20) in SQLServer won't fit into a similar varchar2(20) in Oracle.

I ran across this error yesterday with SSIS loading an Oracle database with the Attunity drivers and thought I would save folks some time.

Setting Android Theme background color

Okay turned out that I made a really silly mistake. The device I am using for testing is running Android 4.0.4, API level 15.

The styles.xml file that I was editing is in the default values folder. I edited the styles.xml in values-v14 folder and it works all fine now.

AES Encryption for an NSString on the iPhone

Since you haven't posted any code, it's difficult to know exactly which problems you're encountering. However, the blog post you link to does seem to work pretty decently... aside from the extra comma in each call to CCCrypt() which caused compile errors.

A later comment on that post includes this adapted code, which works for me, and seems a bit more straightforward. If you include their code for the NSData category, you can write something like this: (Note: The printf() calls are only for demonstrating the state of the data at various points — in a real application, it wouldn't make sense to print such values.)

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSString *key = @"my password";
    NSString *secret = @"text to encrypt";

    NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];
    NSData *cipher = [plain AES256EncryptWithKey:key];
    printf("%s\n", [[cipher description] UTF8String]);

    plain = [cipher AES256DecryptWithKey:key];
    printf("%s\n", [[plain description] UTF8String]);
    printf("%s\n", [[[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding] UTF8String]);

    [pool drain];
    return 0;

Given this code, and the fact that encrypted data will not always translate nicely into an NSString, it may be more convenient to write two methods that wrap the functionality you need, in forward and reverse...

- (NSData*) encryptString:(NSString*)plaintext withKey:(NSString*)key {
    return [[plaintext dataUsingEncoding:NSUTF8StringEncoding] AES256EncryptWithKey:key];

- (NSString*) decryptData:(NSData*)ciphertext withKey:(NSString*)key {
    return [[[NSString alloc] initWithData:[ciphertext AES256DecryptWithKey:key]
                                  encoding:NSUTF8StringEncoding] autorelease];

This definitely works on Snow Leopard, and @Boz reports that CommonCrypto is part of the Core OS on the iPhone. Both 10.4 and 10.5 have /usr/include/CommonCrypto, although 10.5 has a man page for CCCryptor.3cc and 10.4 doesn't, so YMMV.

EDIT: See this follow-up question on using Base64 encoding for representing encrypted data bytes as a string (if desired) using safe, lossless conversions.

How do I detach objects in Entity Framework Code First?

This is an option:

dbContext.Entry(entity).State = EntityState.Detached;

What is the difference between private and protected members of C++ classes?

Protected members can be accessed from derived classes. Private ones can't.

class Base {

  int MyPrivateInt;
  int MyProtectedInt;
  int MyPublicInt;

class Derived : Base
  int foo1()  { return MyPrivateInt;} // Won't compile!
  int foo2()  { return MyProtectedInt;} // OK  
  int foo3()  { return MyPublicInt;} // OK

class Unrelated 
  Base B;
  int foo1()  { return B.MyPrivateInt;} // Won't compile!
  int foo2()  { return B.MyProtectedInt;} // Won't compile
  int foo3()  { return B.MyPublicInt;} // OK

In terms of "best practice", it depends. If there's even a faint possibility that someone might want to derive a new class from your existing one and need access to internal members, make them Protected, not Private. If they're private, your class may become difficult to inherit from easily.

Loading basic HTML in Node.js

It's just really simple if you use pipe. The following is the server.js code snippet.

var http = require('http');_x000D_
var fs = require('fs');_x000D_
function onRequest(req, res){_x000D_
    console.log("USER MADE A REQUEST. " +req.url);_x000D_
    res.writeHead(200, {'Content-Type': 'text/html'});_x000D_
    var readStream = fs.createReadStream(__dirname + '/index.html','utf8'); _x000D_
/*include your html file and directory name instead of <<__dirname + '/index.html'>>*/_x000D_
console.log('Web Server is running...');

Codesign error: Provisioning profile cannot be found after deleting expired profile

  1. Project&Targets Properties -> "Don't Code Sign" -> OK -> cmd+S(or cmd+B);
  2. Project&Targets Properties -> "Your Provision Profile"-> OK

  3. Everything works again!

Convert line endings

Doing this with POSIX is tricky:

  • POSIX Sed does not support \r or \15. Even if it did, the in place option -i is not POSIX

  • POSIX Awk does support \r and \15, however the -i inplace option is not POSIX

  • d2u and dos2unix are not POSIX utilities, but ex is

  • POSIX ex does not support \r, \15, \n or \12

To remove carriage returns:

awk 'BEGIN{RS="^$";ORS="";getline;gsub("\r","");print>ARGV[1]}' file

To add carriage returns:

awk 'BEGIN{RS="^$";ORS="";getline;gsub("\n","\r&");print>ARGV[1]}' file

How can I install a package with go get?

Command go

Download and install packages and dependencies


go get [-d] [-f] [-t] [-u] [-v] [-fix] [-insecure] [build flags] [packages]

Get downloads the packages named by the import paths, along with their dependencies. It then installs the named packages, like 'go install'.

The -d flag instructs get to stop after downloading the packages; that is, it instructs get not to install the packages.

The -f flag, valid only when -u is set, forces get -u not to verify that each package has been checked out from the source control repository implied by its import path. This can be useful if the source is a local fork of the original.

The -fix flag instructs get to run the fix tool on the downloaded packages before resolving dependencies or building the code.

The -insecure flag permits fetching from repositories and resolving custom domains using insecure schemes such as HTTP. Use with caution.

The -t flag instructs get to also download the packages required to build the tests for the specified packages.

The -u flag instructs get to use the network to update the named packages and their dependencies. By default, get uses the network to check out missing packages but does not use it to look for updates to existing packages.

The -v flag enables verbose progress and debug output.

Get also accepts build flags to control the installation. See 'go help build'.

When checking out a new package, get creates the target directory GOPATH/src/. If the GOPATH contains multiple entries, get uses the first one. For more details see: 'go help gopath'.

When checking out or updating a package, get looks for a branch or tag that matches the locally installed version of Go. The most important rule is that if the local installation is running version "go1", get searches for a branch or tag named "go1". If no such version exists it retrieves the default branch of the package.

When go get checks out or updates a Git repository, it also updates any git submodules referenced by the repository.

Get never checks out or updates code stored in vendor directories.

For more about specifying packages, see 'go help packages'.

For more about how 'go get' finds source code to download, see 'go help importpath'.

This text describes the behavior of get when using GOPATH to manage source code and dependencies. If instead the go command is running in module-aware mode, the details of get's flags and effects change, as does 'go help get'. See 'go help modules' and 'go help module-get'.

See also: go build, go install, go clean.

For example, showing verbose output,

$ go get -v (download) (download) (download)

Implode an array with JavaScript?

Use join() method creates and returns a new string by concatenating all of the elements in an array.

Working example

var arr= ['A','b','C','d',1,'2',3,'4'];_x000D_
var res= arr.join('; ')_x000D_

How to load/reference a file as a File instance from the classpath

This also works, and doesn't require a /path/to/file URI conversion. If the file is on the classpath, this will find it.

File currFile = new File(getClass().getClassLoader().getResource("the_file.txt").getFile());

PHP Using RegEx to get substring of a string

Unfortunately, you have a malformed url query string, so a regex technique is most appropriate. See what I mean.

There is no need for capture groups. Just match id= then forget those characters with \K, then isolate the following one or more digital characters.

Code (Demo)

$str = 'producturl.php?id=736375493?=tm';
echo preg_match('~id=\K\d+~', $str, $out) ? $out[0] : 'no match';



Updating the list view when the adapter data changes

I found a solution that is more efficient than currently accepted answer, because current answer forces all list elements to be refreshed. My solution will refresh only one element (that was touched) by calling adapters getView and recycling current view which adds even more efficiency.

mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
      // Edit object data that is represented in Viewat at list's "position"
      view = mAdapter.getView(position, view, parent);

How eliminate the tab space in the column in SQL Server 2008

UPDATE Table SET Column = REPLACE(Column, char(9), '')

Changing Underline color

The easiest way I've tackled this is with CSS:

.redUnderline {
    color: #ff0000;
    border-bottom: 1px solid #000000;
<span class="redUnderline">$username</span>

Also, for an actual underline, if your item is a link, this works:

a.blackUnderline {
   color: #000000;
   text-decoration: underline;
.red {
    color: #ff0000;
<a href="" class="blackUnderline"><span class="red">$username</span></a>

How to Refresh a Component in Angular

Fortunately, if you are using Angular 5.1+, you do not need to implement a hack anymore as native support has been added. You just need to set onSameUrlNavigation to 'reload' in the RouterModule options :

 imports: [RouterModule.forRoot(routes, {onSameUrlNavigation: ‘reload’})],
 exports: [RouterModule],

More information can be found here:

What is the canonical way to trim a string in Ruby without creating a new string?

There's no need to both strip and chomp as strip will also remove trailing carriage returns - unless you've changed the default record separator and that's what you're chomping.

Olly's answer already has the canonical way of doing this in Ruby, though if you find yourself doing this a lot you could always define a method for it:

def strip_or_self!(str)
  str.strip! || str


@title = strip_or_self!(tokens[Title]) if tokens[Title]

Also keep in mind that the if statement will prevent @title from being assigned if the token is nil, which will result in it keeping its previous value. If you want or don't mind @title always being assigned you can move the check into the method and further reduce duplication:

def strip_or_self!(str)
  str.strip! || str if str

As an alternative, if you're feeling adventurous you can define a method on String itself:

class String
  def strip_or_self!
    strip! || self

Giving one of:

@title = tokens[Title].strip_or_self! if tokens[Title]

@title = tokens[Title] && tokens[Title].strip_or_self!

Syntax error "syntax error, unexpected end-of-input, expecting keyword_end (SyntaxError)"

It seems that you have a bunch of describes that never have ends keywords, starting with describe "when email format is invalid" do until describe "when email address is already taken" do

Put an end on those guys and you're probably done =)

how to set width for PdfPCell in ItextSharp

Why not use a PdfPTable object for this? Create a fixed width table and use a float array to set the widths of the columns

PdfPTable table = new PdfPTable(10);
table.HorizontalAlignment = 0;
table.TotalWidth = 500f;
table.LockedWidth = true;
float[] widths = new float[] { 20f, 60f, 60f, 30f, 50f, 80f, 50f, 50f, 50f, 50f };

addCell(table, "SER.\nNO.", 2);

addCell(table, "TYPE OF SHIPPING", 1);
addCell(table, "ORDER NO.", 1);
addCell(table, "QTY.", 1);
addCell(table, "DISCHARGE PPORT", 1);

addCell(table, "DESCRIPTION OF GOODS", 2);

addCell(table, "LINE DOC. RECL DATE", 1);

addCell(table, "CLEARANCE DATE", 2);
addCell(table, "CUSTOM PERMIT NO.", 2);
addCell(table, "DISPATCH DATE", 2);

addCell(table, "AWB/BL NO.", 1);
addCell(table, "COMPLEX NAME", 1);
addCell(table, "G. W. Kgs.", 1);
addCell(table, "DESTINATION", 1);
addCell(table, "OWNER DOC. RECL DATE", 1);


private static void addCell(PdfPTable table, string text, int rowspan)
    BaseFont bfTimes = BaseFont.CreateFont(BaseFont.TIMES_ROMAN, BaseFont.CP1252, false);
    iTextSharp.text.Font times = new iTextSharp.text.Font(bfTimes, 6, iTextSharp.text.Font.NORMAL, iTextSharp.text.BaseColor.BLACK);

    PdfPCell cell = new PdfPCell(new Phrase(text, times));
    cell.Rowspan = rowspan;
    cell.HorizontalAlignment = PdfPCell.ALIGN_CENTER;
    cell.VerticalAlignment = PdfPCell.ALIGN_MIDDLE;

have a look at this tutorial too...

How to force reloading php.ini file?

TL;DR; If you're still having trouble after restarting apache or nginx, also try restarting the php-fpm service.

The answers here don't always satisfy the requirement to force a reload of the php.ini file. On numerous occasions I've taken these steps to be rewarded with no update, only to find the solution I need after also restarting the php-fpm service. So if restarting apache or nginx doesn't trigger a php.ini update although you know the files are updated, try restarting php-fpm as well.

To restart the service:

Note: prepend sudo if not root

Using SysV Init scripts directly:

/etc/init.d/php-fpm restart        # typical
/etc/init.d/php5-fpm restart       # debian-style
/etc/init.d/php7.0-fpm restart     # debian-style PHP 7

Using service wrapper script

service php-fpm restart        # typical
service php5-fpm restart       # debian-style
service php7.0-fpm restart.    # debian-style PHP 7

Using Upstart (e.g. ubuntu):

restart php7.0-fpm         # typical (ubuntu is debian-based) PHP 7
restart php5-fpm           # typical (ubuntu is debian-based)
restart php-fpm            # uncommon

Using systemd (newer servers):

systemctl restart php-fpm.service        # typical
systemctl restart php5-fpm.service       # uncommon
systemctl restart php7.0-fpm.service     # uncommon PHP 7

Or whatever the equivalent is on your system.

The above commands taken directly from this server fault answer

How to generate class diagram from project in Visual Studio 2013?

Because one moderator deleted my detailed image-supported answer on this question, just because I copied and pasted from another question, I am forced to put a less detailed answer and I will link the original answer if you want a more visual way to see the solution.

For Visual Studio 2019 and Visual Studio 2017 Users
For People who are missing this old feature in VS2019 (or maybe VS2017) from the old versions of Visual Studio

This feature still available, but it is NOT available by default, you have to install it separately.

  1. Open VS 2019 go to Tools -> Get Tools and Features
  2. Select the Individual components tab and search for Class Designer
  3. Select this Component and Install it, After finish installing this component (you may need to restart visual studio)
  4. Right-click on the project and select Add -> Add New Item
  5. Search for 'class' word and NOW you can see Class Diagram component

see this answer also to see an image associated

(whish that the moderator realized this is the same question and instead of deleting my answer, he could mark one of the questions as duplicated to the other)

Update to create a class-diagram for the whole project
I received a downvote because I did not mention how to generate a diagram for the whole project, here is how to do it (after applying the previous steps)

  1. Add class diagram to the project
  2. if the option Preview Selected Items is enabled in the solution explorer, disabled it temporarily, you can re-enable it later

enter image description here

  1. open the class diagram that you created in step 2 (by double-clicking on it)
  2. drag-and-drop the project from the solution explorer to the class diagram

you could be shocked by the results to the point that you can change your mind and remove your downvote (please do NOT upvote, it is enough to remove your downvote)

Is there any way to show a countdown on the lockscreen of iphone?

A today extension would be the most fitting solution.

Also you could do something on the lock screen with local notifications queued up to fire at regular intervals showing the latest countdown value.

ng is not recognized as an internal or external command

Just open your command prompt (run as administrator). Ensure node --v is 6.9.0 or higher and npm --v is 3.0.0 r higher.

After that run the following command:

npm install -g @angular/cli

Once angular is installed. you can see an entry of angular cli in the path


Then try ng help. It will work.

How to check if a file is a valid image file?

One option is to use the filetype package.


python -m pip install filetype


  1. Quick: Does its work by loading the first few bytes of your image (check on the magic number)
  2. Supports different mime type: Images, Videos, Fonts, Audio, Archives.


filetype >= 1.0.7

import filetype

filename = "/path/to/file.jpg"

if filetype.is_image(filename):
    print(f"{filename} is a valid image...")
elif filetype.is_video(filename):
    print(f"{filename} is a valid video...")

filetype <= 1.0.6

import filetype

filename = "/path/to/file.jpg"

if filetype.image(filename):
    print(f"{filename} is a valid image...")
    print(f"{filename} is a valid video...")

Additional information on the official repo:

Run/install/debug Android applications over Wi-Fi?

I wrote a simple script for Windows:

Step 1. Make a batch file with the below commands and call the file wifi_dedug.bat and copy the below contents:

    adb tcpip 5555
    adb shell "ip addr show wlan0  | grep 'inet ' | cut -d' ' -f6|cut -d/ -f1" > tmpFile 
    set /p ip= < tmpFile 
    @echo %ip%
    del tmpFile
    @echo %ip%
    adb connect %ip%

Step 2. connect your device to pc.

Step 3. start batch file (key enter when requested)

Step 4. disconnect your device and deploy/debug via wifi.

What does the ^ (XOR) operator do?

The (^) XOR operator generates 1 when it is applied on two different bits (0 and 1). It generates 0 when it is applied on two same bits (0 and 0 or 1 and 1).

Display fullscreen mode on Tkinter

I think this is what you're looking for:

Tk.attributes("-fullscreen", True)  # substitute `Tk` for whatever your `Tk()` object is called

You can use wm_attributes instead of attributes, too.

Then just bind the escape key and add this to the handler:

Tk.attributes("-fullscreen", False)

An answer to another question alluded to this (with wm_attributes). So, that's how I found out. But, no one just directly went out and said it was the answer for some reason. So, I figured it was worth posting.

Here's a working example (tested on Xubuntu 14.04) that uses F11 to toggle fullscreen on and off and where escape will turn it off only:

import sys
if sys.version_info[0] == 2:  # Just checking your Python version to import Tkinter properly.
    from Tkinter import *
    from tkinter import *

class Fullscreen_Window:

    def __init__(self): = Tk()'-zoomed', True)  # This just maximizes it so we can see the window. It's nothing to do with fullscreen.
        self.frame = Frame(
        self.state = False"<F11>", self.toggle_fullscreen)"<Escape>", self.end_fullscreen)

    def toggle_fullscreen(self, event=None):
        self.state = not self.state  # Just toggling the boolean"-fullscreen", self.state)
        return "break"

    def end_fullscreen(self, event=None):
        self.state = False"-fullscreen", False)
        return "break"

if __name__ == '__main__':
    w = Fullscreen_Window()

If you want to hide a menu, too, there are only two ways I've found to do that. One is to destroy it. The other is to make a blank menu to switch between.  # self.blank_menu is a Menu object

Then switch it back to your menu when you want it to show up again.  # is your menu.

Connect to SQL Server Database from PowerShell

Integrated Security and User ID \ Password authentication are mutually exclusive. To connect to SQL Server as the user running the code, remove User ID and Password from your connection string:

$SqlConnection.ConnectionString = "Server = $SQLServer; Database = $SQLDBName; Integrated Security = True;"

To connect with specific credentials, remove Integrated Security:

$SqlConnection.ConnectionString = "Server = $SQLServer; Database = $SQLDBName; User ID = $uid; Password = $pwd;"

VBA EXCEL To Prompt User Response to Select Folder and Return the Path as String Variable


Function GetFolder() As String
    Dim fldr As FileDialog
    Dim sItem As String
    Set fldr = Application.FileDialog(msoFileDialogFolderPicker)
    With fldr
        .Title = "Select a Folder"
        .AllowMultiSelect = False
        .InitialFileName = Application.DefaultFilePath
        If .Show <> -1 Then GoTo NextCode
        sItem = .SelectedItems(1)
    End With
    GetFolder = sItem
    Set fldr = Nothing
End Function

This code was adapted from Ozgrid

and as jkf points out, from Mr Excel

How to connect to SQL Server from command prompt with Windows authentication

You can use different syntax to achieve different things. If it is windows authentication you want, you could try this:

sqlcmd /S  /d  -E

If you want to use SQL Server authentication you could try this:

sqlcmd /S  /d -U -P 


/S = the servername/instance name. Example: Pete's Laptop/SQLSERV
/d = the database name. Example: Botlek1
-E = Windows authentication.
-U = SQL Server authentication/user. Example: Pete
-P = password that belongs to the user. Example: 1234

Hope this helps!

How to update SQLAlchemy row entry?

user.no_of_logins += 1

Python Brute Force algorithm

itertools is ideally suited for this:

                               for l in itertools.product(charset, repeat=i))
                              for i in range(1, maxlen + 1))

Difference between two numpy arrays in python

You can also use numpy.subtract

It has the advantage over the difference operator, -, that you do not have to transform the sequences (list or tuples) into a numpy arrays — you save the two commands:

array1 = np.array([1.1, 2.2, 3.3])
array2 = np.array([1, 2, 3])

Example: (Python 3.5)

import numpy as np
result = np.subtract([1.1, 2.2, 3.3], [1, 2, 3])
print ('the difference =', result)

which gives you

the difference = [ 0.1  0.2  0.3]

Remember, however, that if you try to subtract sequences (lists or tuples) with the - operator you will get an error. In this case, you need the above commands to transform the sequences in numpy arrays

Wrong Code:

print([1.1, 2.2, 3.3] - [1, 2, 3])

javascript: Disable Text Select

Simple Copy this text and put on the before </body>

function disableselect(e) {
  return false

function reEnable() {
  return true

document.onselectstart = new Function ("return false")

if (window.sidebar) {
  document.onmousedown = disableselect
  document.onclick = reEnable

How to get terminal's Character Encoding

To my knowledge, no.

Circumstantial indications from $LC_CTYPE, locale and such might seem alluring, but these are completely separated from the encoding the terminal application (actually an emulator) happens to be using when displaying characters on the screen.

They only way to detect encoding for sure is to output something only present in the encoding, e.g. ä, take a screenshot, analyze that image and check if the output character is correct.

So no, it's not possible, sadly.

How to create materialized views in SQL Server?

You might need a bit more background on what a Materialized View actually is. In Oracle these are an object that consists of a number of elements when you try to build it elsewhere.

An MVIEW is essentially a snapshot of data from another source. Unlike a view the data is not found when you query the view it is stored locally in a form of table. The MVIEW is refreshed using a background procedure that kicks off at regular intervals or when the source data changes. Oracle allows for full or partial refreshes.

In SQL Server, I would use the following to create a basic MVIEW to (complete) refresh regularly.

First, a view. This should be easy for most since views are quite common in any database Next, a table. This should be identical to the view in columns and data. This will store a snapshot of the view data. Then, a procedure that truncates the table, and reloads it based on the current data in the view. Finally, a job that triggers the procedure to start it's work.

Everything else is experimentation.

Crontab Day of the Week syntax

    :-) Sunday    |    0  ->  Sun
        Monday    |    1  ->  Mon
       Tuesday    |    2  ->  Tue
     Wednesday    |    3  ->  Wed
      Thursday    |    4  ->  Thu
        Friday    |    5  ->  Fri
      Saturday    |    6  ->  Sat
    :-) Sunday    |    7  ->  Sun

As you can see above, and as said before, the numbers 0 and 7 are both assigned to Sunday. There are also the English abbreviated days of the week listed, which can also be used in the crontab.

Examples of Number or Abbreviation Use

15 09 * * 5,6,0             command
15 09 * * 5,6,7             command
15 09 * * 5-7               command
15 09 * * Fri,Sat,Sun       command

The four examples do all the same and execute a command every Friday, Saturday, and Sunday at 9.15 o'clock.

In Detail

Having two numbers 0 and 7 for Sunday can be useful for writing weekday ranges starting with 0 or ending with 7. So you can write ranges starting with Sunday or ending with it, like 0-2 or 5-7 for example (ranges must start with the lower number and must end with the higher). The abbreviations cannot be used to define a weekday range.

sql searching multiple words in a string

if you put all the searched words in a temporaray table say @tmp and column col1, then you could try this:

Select * from T where C like (Select '%'+col1+'%' from @temp);

Make Vim show ALL white spaces as a character

I didn't find exactly what I wanted from the existing answers. The code below will highlight all trailing spaces bright red. Simply add the following to your .vimrc

highlight ExtraWhitespace ctermbg=red guibg=red
match ExtraWhitespace /\s\+$/
autocmd BufWinEnter * match ExtraWhitespace /\s\+$/
autocmd InsertEnter * match ExtraWhitespace /\s\+\%#\@<!$/
autocmd InsertLeave * match ExtraWhitespace /\s\+$/
autocmd BufWinLeave * call clearmatches()

Dynamic constant assignment

Constants in ruby cannot be defined inside methods. See the notes at the bottom of this page, for example

link_to method and click event in Rails

You can use link_to_function (removed in Rails 4.1):

link_to_function 'My link with obtrusive JavaScript', 'alert("Oh no!")'

Or, if you absolutely need to use link_to:

link_to 'Another link with obtrusive JavaScript', '#',
        :onclick => 'alert("Please no!")'

However, putting JavaScript right into your generated HTML is obtrusive, and is bad practice.

Instead, your Rails code should simply be something like this:

link_to 'Link with unobtrusive JavaScript',
        :id => 'my-link'

And assuming you're using the Prototype JS framework, JS like this in your application.js:

$('my-link').observe('click', function (event) {
  event.stop(); // Prevent link from following through to its given href

Or if you're using jQuery:

$('#my-link').click(function (event) {
  event.preventDefault(); // Prevent link from following its href

By using this third technique, you guarantee that the link will follow through to some other page—not just fail silently—if JavaScript is unavailable for the user. Remember, JS could be unavailable because the user has a poor internet connection (e.g., mobile device, public wifi), the user or user's sysadmin disabled it, or an unexpected JS error occurred (i.e., developer error).

Removing an activity from the history stack

Just set noHistory="true" in Manifest file. It makes activity being removed from the backstack.

jquery : focus to div is not working

you can use the below code to bring focus to a div, in this example the page scrolls to the <div id="navigation">

$('html, body').animate({ scrollTop: $('#navigation').offset().top }, 'slow');

To delay JavaScript function call using jQuery

Since you declare sample inside the anonymous function you pass to ready, it is scoped to that function.

You then pass a string to setTimeout which is evaled after 2 seconds. This takes place outside the current scope, so it can't find the function.

Only pass functions to setTimeout, using eval is inefficient and hard to debug.


Cannot find pkg-config error


What is the difference between java and core java?

It's not an official term. I guess it means knowledge of the Java language itself and the most important parts of the standard API (java.lang,, java.utils packages, basically), as opposed to the multitude of specialzed APIs and frameworks (J2EE, JPA, JNDI, JSTL, ...) that are often required for Java jobs.

Android: how to draw a border to a LinearLayout

Do you really need to do that programmatically?

Just considering the title: You could use a ShapeDrawable as android:background…

For example, let's define res/drawable/my_custom_background.xml as:

<shape xmlns:android=""
      android:bottomLeftRadius="0dp" />
      android:color="@android:color/white" />

and define android:background="@drawable/my_custom_background".

I've not tested but it should work.


I think that's better to leverage the xml shape drawable resource power if that fits your needs. With a "from scratch" project (for android-8), define res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
    android:padding="10dip" >
        android:text="Hello World, SOnich"
    [... more TextView ...]
        android:text="Hello World, SOnich"

and a res/drawable/border.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android=""
        android:color="@android:color/white" />

Reported to work on a gingerbread device. Note that you'll need to relate android:padding of the LinearLayout to the android:width shape/stroke's value. Please, do not use @android:color/white in your final application but rather a project defined color.

You could apply android:background="@drawable/border" android:padding="10dip" to each of the LinearLayout from your provided sample.

As for your other posts related to display some circles as LinearLayout's background, I'm playing with Inset/Scale/Layer drawable resources (see Drawable Resources for further information) to get something working to display perfect circles in the background of a LinearLayout but failed at the moment…

Your problem resides clearly in the use of getBorder.set{Width,Height}(100);. Why do you do that in an onClick method?

I need further information to not miss the point: why do you do that programmatically? Do you need a dynamic behavior? Your input drawables are png or ShapeDrawable is acceptable? etc.

To be continued (maybe tomorrow and as soon as you provide more precisions on what you want to achieve)…

How to generate a HTML page dynamically using PHP?

I've been working kind of similar to this and I have some code that might help you. The live example is here and below, is the code I'm using for you to have it as reference.



// Session is started.

// Name of the template file.
$template_file = 'couples-template.php';

// Root folder if working in subdirectory. Name is up to you ut must match with server's folder.
$base_path = '/couple/';

// Path to the directory where you store the "couples-template.php" file.
$template_path = '../template/';

// Path to the directory where php will store the auto-generated couple's pages.
$couples_path = '../couples/';

// Posted data.
$data['groom-name'] = str_replace(' ', '', $_POST['groom-name']);
$data['bride-name'] = str_replace(' ', '', $_POST['bride-name']);
// $data['groom-surname'] = $_POST['groom-surname'];
// $data['bride-surname'] = $_POST['bride-surname'];
$data['wedding-date'] = $_POST['wedding-date'];
$data['email'] = $_POST['email'];
$data['code'] = str_replace(array('/', '-', ' '), '', $_POST['wedding-date']).strtoupper(substr($data['groom-name'], 0, 1)).urlencode('&').strtoupper(substr($data['bride-name'], 0, 1));

// Data array (Should match with data above's order).
$placeholders = array('{groom-name}', '{bride-name}', '{wedding-date}', '{email}', '{code}');

// Get the couples-template.php as a string.
$template = file_get_contents($template_path.$template_file);

// Fills the template.
$new_file = str_replace($placeholders, $data, $template);

// Generates couple's URL and makes it frendly and lowercase.
$couples_url = str_replace(' ', '', strtolower($data['groom-name'].'-'.$data['bride-name'].'.php'));

// Save file into couples directory.
$fp = fopen($couples_path.$couples_url, 'w');
fwrite($fp, $new_file);

// Set the variables to pass them to success page.
$_SESSION['couples_url'] = $couples_url;
// If working in root directory.
$_SESSION['couples_path'] = str_replace('.', '', $couples_path);
// If working in a sub directory.
//$_SESSION['couples_path'] = substr_replace($base_path, '', -1).str_replace('.', '',$couples_path);

header('Location: success.php');


Hope this file can help and work as reference to start and boost your project.

Get current user id in ASP.NET Identity 2.0

In order to get CurrentUserId in Identity 2.0, at first import Microsoft.AspNet.Identity:


using Microsoft.AspNet.Identity;


Imports Microsoft.AspNet.Identity

And then call User.Identity.GetUserId() everywhere you want:

strCurrentUserId = User.Identity.GetUserId()

This method returns current user id as defined datatype for userid in database (the default is String).

How to get input textfield values when enter key is pressed in react js?


<input id="something" onkeyup="key_up(this)" type="text">


function key_up(e){
    var enterKey = 13; //Key Code for Enter Key
    if (e.which == enterKey){
        //Do you work here

Next time, Please try providing some code.

How to prompt for user input and read command-line arguments

raw_input is no longer available in Python 3.x. But raw_input was renamed input, so the same functionality exists.

input_var = input("Enter something: ")
print ("you entered " + input_var) 

Documentation of the change

git reset --hard HEAD leaves untracked files behind

User interactive approach:

git clean -i -fd

Remove .classpath [y/N]? N
Remove .gitignore [y/N]? N
Remove .project [y/N]? N
Remove .settings/ [y/N]? N
Remove src/com/amazon/arsdumpgenerator/inspector/ [y/N]? y
Remove src/com/amazon/arsdumpgenerator/manifest/ [y/N]? y
Remove src/com/amazon/arsdumpgenerator/s3/ [y/N]? y
Remove tst/com/amazon/arsdumpgenerator/manifest/ [y/N]? y
Remove tst/com/amazon/arsdumpgenerator/s3/ [y/N]? y

-i for interactive
-f for force
-d for directory
-x for ignored files(add if required)

Note: Add -n or --dry-run to just check what it will do.

How do I create a new branch?

My solution if you work with the Trunk/ and Release/ workflow:

Right click on Trunk/ which you will be creating your Branch from:


Select Branch/Tag:


Type in location of your new branch, commit message, and any externals (if your repository has them):

enter image description here

Asyncio.gather vs asyncio.wait

Although similar in general cases ("run and get results for many tasks"), each function has some specific functionality for other cases:


Returns a Future instance, allowing high level grouping of tasks:

import asyncio
from pprint import pprint

import random

async def coro(tag):
    print(">", tag)
    await asyncio.sleep(random.uniform(1, 3))
    print("<", tag)
    return tag

loop = asyncio.get_event_loop()

group1 = asyncio.gather(*[coro("group 1.{}".format(i)) for i in range(1, 6)])
group2 = asyncio.gather(*[coro("group 2.{}".format(i)) for i in range(1, 4)])
group3 = asyncio.gather(*[coro("group 3.{}".format(i)) for i in range(1, 10)])

all_groups = asyncio.gather(group1, group2, group3)

results = loop.run_until_complete(all_groups)



All tasks in a group can be cancelled by calling group2.cancel() or even all_groups.cancel(). See also .gather(..., return_exceptions=True),


Supports waiting to be stopped after the first task is done, or after a specified timeout, allowing lower level precision of operations:

import asyncio
import random

async def coro(tag):
    print(">", tag)
    await asyncio.sleep(random.uniform(0.5, 5))
    print("<", tag)
    return tag

loop = asyncio.get_event_loop()

tasks = [coro(i) for i in range(1, 11)]

print("Get first result:")
finished, unfinished = loop.run_until_complete(
    asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED))

for task in finished:
print("unfinished:", len(unfinished))

print("Get more results in 2 seconds:")
finished2, unfinished2 = loop.run_until_complete(
    asyncio.wait(unfinished, timeout=2))

for task in finished2:
print("unfinished2:", len(unfinished2))

print("Get all other results:")
finished3, unfinished3 = loop.run_until_complete(asyncio.wait(unfinished2))

for task in finished3:


Java Array, Finding Duplicates

@andersoj gave a great answer, but I also want add new simple way

    private boolean checkDuplicateBySet(Integer[] zipcodeList) {
        Set<Integer> zipcodeSet = new HashSet(Arrays.asList(zipcodeList));
        if (zipcodeSet.size() == zipcodeList.length) {
            return true;
        return false;

In case zipcodeList is int[], you need convert int[] to Integer[] first(It not auto-boxing), code here

Complete code will be:

    private boolean checkDuplicateBySet2(int[] zipcodeList) {
        Integer[] zipcodeIntegerArray = new Integer[zipcodeList.length];
        for (int i = 0; i < zipcodeList.length; i++) {
            zipcodeIntegerArray[i] = Integer.valueOf(zipcodeList[i]);

        Set<Integer> zipcodeSet = new HashSet(Arrays.asList(zipcodeIntegerArray));
        if (zipcodeSet.size() == zipcodeList.length) {
            return true;
        return false;

Hope this helps!

Spark DataFrame TimestampType - how to get Year, Month, Day values from field?

Actually, we really do not need to import any python library. We can separate the year, month, date using simple SQL. See the below example,

|       _c0|

I have a date column in my data frame which contains the date, month and year and assume I want to extract only the year from the column.

sqlDF = spark.sql("SELECT EXTRACT(year from `_c0`) FROM res ")

Here I'm creating a temporary view and store the year values using this single line and the output will be,

|year(CAST(_c0 AS DATE))|
|                   1872|
|                   1873|
|                   1874|
|                   1875|
|                   1876|
|                   1876|
|                   1877|
|                   1877|
|                   1878|
|                   1878|
|                   1879|
|                   1879|
|                   1879|

How to compile LEX/YACC files on Windows?

You can find the latest windows version of flex & bison here:

Remove white space below image

If you would like to preserve the image as inline you can put vertical-align: top or vertical-align: bottom on it. By default it is aligned on the baseline hence the few pixels beneath it.

What is the maximum number of edges in a directed graph with n nodes?

In the graph with self loop

max edges= n*n

such as we have 4 nodes(vertex)

4 nodes = 16 edges= 4*4

Adding Google Play services version to your app's manifest?

In my case i had to install google repository from the SDK manager.

How do I check if the user is pressing a key?

Try this:

import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Main {

    public static void main(String[] argv) throws Exception {

    JTextField textField = new JTextField();

    textField.addKeyListener(new Keychecker());

    JFrame jframe = new JFrame();


    jframe.setSize(400, 350);



class Keychecker extends KeyAdapter {

    public void keyPressed(KeyEvent event) {

        char ch = event.getKeyChar();




Cloning a private Github repo

This worked for me:

git clone https://[email protected]/username/repo_name

How to read a config file using python

You need a section in your file:

[My Section]
path1 = D:\test1\first
path2 = D:\test2\second
path3 = D:\test2\third

Then, read the properties:

import ConfigParser

config = ConfigParser.ConfigParser()
path1 = config.get('My Section', 'path1')
path2 = config.get('My Section', 'path2')
path3 = config.get('My Section', 'path3')

Parsing string as JSON with single quotes?

I know it's an old post, but you can use JSON5 for this purpose.

<script src="json5.js"></script>

TypeError: 'dict_keys' object does not support indexing

In Python 2 dict.keys() return a list, whereas in Python 3 it returns a generator.

You could only iterate over it's values else you may have to explicitly convert it to a list i.e. pass it to a list function.

Converting a sentence string to a string array of words in Java

Most of the answers here convert String to String Array as the question asked. But Generally we use List , so more useful will be -

String dummy = "This is a sample sentence.";
List<String> wordList= Arrays.asList(dummy.split(" "));

Are SSL certificates bound to the servers ip address?

The SSL certificates are going to be bound to hostname rather than IP if they are setup in the standard way. Hence why it works at one site rather than the other.

Even if the servers share the same hostname they may well have two different certificates and hence WebSphere will have a certificate trust issue as it won't be able to recognise the certificate on the second server as it is different to the first.

Spring Security with roles and permissions

Just for sake of completeness (maybe someone else won't have to implement it from scratch):

We've implemented our own small library, as everyone else. It's supposed to make things easier, so that our developers don't have to reimplement it each time. It would be great if spring security would provide support of rbac out of the box, as this approach is much better than the default permission based one.

Have a look at Github (OSS, MIT license) to see if it suits your needs. It's basically only addressing the role <-> privileges mapping. The missing piece, you'll have to provide on your own is basically the user <-> roles mapping, e.g. by mapping groups (racf/ad groups) to roles (1:1) or by implementing an additional mapping. That one's different in each project, so it doesn't make sense to provide some implementation.

We've basically used this internally, so that we can start with rbac from the beginning. We can still replace it with some other implementation later on, if the application is growing, but it's important for us to get the setup right at the beginning.

If you don't use rbac, there's a good chance, that the permissions are scattered throughout the codebase and you'll have a hard time to extract/group those (into roles) later on. The generated graphs do also help to reason about it/restructure it later on.

What is w3wp.exe?

w3wp.exe is a process associated with the application pool in IIS. If you have more than one application pool, you will have more than one instance of w3wp.exe running. This process usually allocates large amounts of resources. It is important for the stable and secure running of your computer and should not be terminated.

You can get more information on w3wp.exe here

How to convert ASCII code (0-255) to its corresponding character?

One can iterate from a to z like this

int asciiForLowerA = 97;
int asciiForLowerZ = 122;
for(int asciiCode = asciiForLowerA; asciiCode <= asciiForLowerZ; asciiCode++){
    search(sCurrentLine, searchKey + Character.toString ((char) asciiCode));

How to set selected index JComboBox by value

public static void setSelectedValue(JComboBox comboBox, int value)
        ComboItem item;
        for (int i = 0; i < comboBox.getItemCount(); i++)
            item = (ComboItem)comboBox.getItemAt(i);
            if (item.getValue().equalsIgnoreCase(value))

Hope this help :)

alternatives to REPLACE on a text or ntext datatype

Assuming SQL Server 2000, the following StackOverflow question should address your problem.

If using SQL Server 2005/2008, you can use the following code (taken from here):

select cast(replace(cast(myntext as nvarchar(max)),'find','replace') as ntext)
from myntexttable

How do I import other TypeScript files?

From TypeScript version 1.8 you can use simple import statements just like in ES6:

import { ZipCodeValidator } from "./ZipCodeValidator";

let myValidator = new ZipCodeValidator();

Old answer: From TypeScript version 1.5 you can use tsconfig.json:

It completely eliminates the need of the comment style referencing.

Older answer:

You need to reference the file on the top of the current file.

You can do this like this:

/// <reference path="../typings/jquery.d.ts"/>
/// <reference path="components/someclass.ts"/>

class Foo { }


These paths are relative to the current file.

Your example:

/// <reference path="moo.ts"/>

class bar extends

CardView not showing Shadow in Android L

Add this line to CardView....

card_view:cardUseCompatPadding="true" //for enable shadow
card_view:cardElevation="9dp" // this for how much shadow you want to show


You can avoid layout_marginTop and layout_marginBottom as shadow itself takes some space to the up and down of it.The amount space defined by how much you will use in card_view:cardElevation="ndp" .

Happy Coding (:

What exactly is RESTful programming?

Old question, newish way of answering. There's a lot of misconception out there about this concept. I always try to remember:

  1. Structured URLs and Http Methods/Verbs are not the definition of restful programming.
  2. JSON is not restful programming
  3. RESTful programming is not for APIs

I define restful programming as

An application is restful if it provides resources (being the combination of data + state transitions controls) in a media type the client understands

To be a restful programmer you must be trying to build applications that allow actors to do things. Not just exposing the database.

State transition controls only make sense if the client and server agree upon a media type representation of the resource. Otherwise there's no way to know what's a control and what isn't and how to execute a control. IE if browsers didn't know <form> tags in html then there'd be nothing for you to submit to transition state in your browser.

I'm not looking to self promote, but i expand on these ideas to great depth in my talk .

An excerpt from my talk is about the often referred to richardson maturity model, i don't believe in the levels, you either are RESTful (level 3) or you are not, but what i like to call out about it is what each level does for you on your way to RESTful

annotated richardson maturity model

CSS, Images, JS not loading in IIS

Add this to your web.config

<location path="Images">
            <allow users="*" />

Incrementing a variable inside a Bash loop

You're getting final 0 because your while loop is being executed in a sub (shell) process and any changes made there are not reflected in the current (parent) shell.

Correct script:

while read -r country _; do
  if [ "US" = "$country" ]; then
        echo "US counter $USCOUNTER"
done < "$FILE"

How to run functions in parallel?

This can be done elegantly with Ray, a system that allows you to easily parallelize and distribute your Python code.

To parallelize your example, you'd need to define your functions with the @ray.remote decorator, and then invoke them with .remote.

import ray


dir1 = 'C:\\folder1'
dir2 = 'C:\\folder2'
filename = 'test.txt'
addFiles = [25, 5, 15, 35, 45, 25, 5, 15, 35, 45]

# Define the functions. 
# You need to pass every global variable used by the function as an argument.
# This is needed because each remote function runs in a different process,
# and thus it does not have access to the global variables defined in 
# the current process.
def func1(filename, addFiles, dir):
    # func1() code here...

def func2(filename, addFiles, dir):
    # func2() code here...

# Start two tasks in the background and wait for them to finish.
ray.get([func1.remote(filename, addFiles, dir1), func2.remote(filename, addFiles, dir2)]) 

If you pass the same argument to both functions and the argument is large, a more efficient way to do this is using ray.put(). This avoids the large argument to be serialized twice and to create two memory copies of it:

largeData_id = ray.put(largeData)

ray.get([func1(largeData_id), func2(largeData_id)])

Important - If func1() and func2() return results, you need to rewrite the code as follows:

ret_id1 = func1.remote(filename, addFiles, dir1)
ret_id2 = func2.remote(filename, addFiles, dir2)
ret1, ret2 = ray.get([ret_id1, ret_id2])

There are a number of advantages of using Ray over the multiprocessing module. In particular, the same code will run on a single machine as well as on a cluster of machines. For more advantages of Ray see this related post.

How to create custom spinner like border around the spinner with down triangle on the right side?

To change only "background" (add corners, change color, ....) you can put it into FrameLayout with wanted background drawable, else you need to make nine patch background for to not lose spinner arrow. Spinner background is transparent.

How do I get time of a Python program's execution?

Similar to the response from @rogeriopvl I added a slight modification to convert to hour minute seconds using the same library for long running jobs.

import time
start_time = time.time()
seconds = time.time() - start_time
print('Time Taken:', time.strftime("%H:%M:%S",time.gmtime(seconds)))

Sample Output

Time Taken: 00:00:08

Select from multiple tables without a join?

You should try this

 SELECT t1.*,t2.* FROM t1,t2

How to label each equation in align environment?

\tag also works in align*. Example:

  a(x)^{2} &= bx\tag{1}\\ 
  a(x)^{2} &= b\tag{2}\\ 
  ax &= b\tag{3}\\ 
  a(x)^{2}+bx &= c\tag{4}\\ 
  a(x)^{2}+c &= bx\tag{5}\\ 
  a(x)^{2} &= bx+c\tag{6}\\ \\ 
  Where\quad a, b, c \, \in N


PDF output for \tag example

Git says local branch is behind remote branch, but it's not

You probably did some history rewriting? Your local branch diverged from the one on the server. Run this command to get a better understanding of what happened:

gitk HEAD @{u}

I would strongly recommend you try to understand where this error is coming from. To fix it, simply run:

git push -f

The -f makes this a “forced push” and overwrites the branch on the server. That is very dangerous when you are working in team. But since you are on your own and sure that your local state is correct this should be fine. You risk losing commit history if that is not the case.

Ansible - read inventory hosts and variables to group_vars/all file

- name: host
   debug: msg="{{ item }}" 
    - "{{ groups['tests'] }}"

This piece of code will give the message:


as groups['tests'] basically return a list of unique ip addresses ['',''] whereas groups['tomcat'][0] returns

Socket File "/var/pgsql_socket/.s.PGSQL.5432" Missing In Mountain Lion (OS X Server)

I had this problem with Django.

Fix it by explicitly setting your hostname to "localhost".

How does functools partial do what it does?

Partials can be used to make new derived functions that have some input parameters pre-assigned

To see some real world usage of partials, refer to this really good blog post:

A simple but neat beginner's example from the blog, covers how one might use partial on to make code more readable. method's signature is:

search(pattern, string, flags=0) 

By applying partial we can create multiple versions of the regular expression search to suit our requirements, so for example:

is_spaced_apart = partial(, '[a-zA-Z]\s\=')
is_grouped_together = partial(, '[a-zA-Z]\=')

Now is_spaced_apart and is_grouped_together are two new functions derived from that have the pattern argument applied(since pattern is the first argument in the method's signature).

The signature of these two new functions(callable) is:

is_spaced_apart(string, flags=0)     # pattern '[a-zA-Z]\s\=' applied
is_grouped_together(string, flags=0) # pattern '[a-zA-Z]\=' applied

This is how you could then use these partial functions on some text:

for text in lines:
    if is_grouped_together(text):
    elif is_spaced_apart(text):

You can refer the link above to get a more in depth understanding of the subject, as it covers this specific example and much more..

PostgreSQL Error: Relation already exists

In my case, I had a sequence with the same name.

ERROR 1148: The used command is not allowed with this MySQL version

I find the answer here.

It's because the server variable local_infile is set to FALSE|0. Refer from the document.

You can verify by executing:

SHOW VARIABLES LIKE 'local_infile';

If you have SUPER privilege you can enable it (without restarting server with a new configuration) by executing:

SET GLOBAL local_infile = 1;

How to reshape data from long to wide format

The new (in 2014) tidyr package also does this simply, with gather()/spread() being the terms for melt/cast.

Edit: Now, in 2019, tidyr v 1.0 has launched and set spread and gather on a deprecation path, preferring instead pivot_wider and pivot_longer, which you can find described in this answer. Read on if you want a brief glimpse into the brief life of spread/gather.

spread(dat1, key = numbers, value = value)

From github,

tidyr is a reframing of reshape2 designed to accompany the tidy data framework, and to work hand-in-hand with magrittr and dplyr to build a solid pipeline for data analysis.

Just as reshape2 did less than reshape, tidyr does less than reshape2. It's designed specifically for tidying data, not the general reshaping that reshape2 does, or the general aggregation that reshape did. In particular, built-in methods only work for data frames, and tidyr provides no margins or aggregation.

Can you style an html radio button to look like a checkbox?

In CSS3:

input[type=radio] {content:url(mycheckbox.png)}
input[type=radio]:checked {content:url(mycheckbox-checked.png)}

In reality:

<span class=fakecheckbox><input type=radio><img src="checkbox.png" alt=""></span>

@media screen {.fakecheckbox img {display:none}}
@media print {.fakecheckbox input {display:none;}}

and you'll need Javascript to keep <img> and radios in sync (and ideally insert them there in a first place).

I've used <img>, because browsers are usually configured not to print background-image. It's better to use image than another control, because image is non-interactive and less likely to cause problems.

What is the difference between bool and Boolean types in C#

bool is a primitive type, meaning that the value (true/false in this case) is stored directly in the variable. Boolean is an object. A variable of type Boolean stores a reference to a Boolean object. The only real difference is storage. An object will always take up more memory than a primitive type, but in reality, changing all your Boolean values to bool isn't going to have any noticeable impact on memory usage.

I was wrong; that's how it works in java with boolean and Boolean. In C#, bool and Boolean are both reference types. Both of them store their value directly in the variable, both of them cannot be null, and both of them require a "convertTO" method to store their values in another type (such as int). It only matters which one you use if you need to call a static function defined within the Boolean class.

How to configure socket connect timeout

There should be a ReceiveTimeout property in the Socket class.

Socket.ReceiveTimeout Property

Can´t run .bat file under windows 10

There is no inherent reason that a simple batch file would run in XP but not Windows 10. It is possible you are referencing a command or a 3rd party utility that no longer exists. To know more about what is actually happening, you will need to do one of the following:

  • Add a pause to the batch file so that you can see what is happening before it exits.
    1. Right click on one of the .bat files and select "edit". This will open the file in notepad.
    2. Go to the very end of the file and add a new line by pressing "enter".
    3. type pause.
    4. Save the file.
    5. Run the file again using the same method you did before.

- OR -

  • Run the batch file from a static command prompt so the window does not close.
    1. In the folder where the .bat files are located, hold down the "shift" key and right click in the white space.
    2. Select "Open Command Window Here".
    3. You will now see a new command prompt. Type in the name of the batch file and press enter.

Once you have done this, I recommend creating a new question with the output you see after using one of the methods above.

React JS get current date

OPTION 1: if you want to make a common utility function then you can use this

export function getCurrentDate(separator=''){

let newDate = new Date()
let date = newDate.getDate();
let month = newDate.getMonth() + 1;
let year = newDate.getFullYear();

return `${year}${separator}${month<10?`0${month}`:`${month}`}${separator}${date}`

and use it by just importing it as

import {getCurrentDate} from './utils'

OPTION 2: or define and use in a class directly


let newDate = new Date()
let date = newDate.getDate();
let month = newDate.getMonth() + 1;
let year = newDate.getFullYear();

return `${year}${separator}${month<10?`0${month}`:`${month}`}${separator}${date}`

How can I implement a tree in Python?

A generic tree is a node with zero or more children, each one a proper (tree) node. It isn't the same as a binary tree, they're different data structures, although both shares some terminology.

There isn't any builtin data structure for generic trees in Python, but it's easily implemented with classes.

class Tree(object):
    "Generic tree node."
    def __init__(self, name='root', children=None): = name
        self.children = []
        if children is not None:
            for child in children:
    def __repr__(self):
    def add_child(self, node):
        assert isinstance(node, Tree)
#    *
#   /|\
#  1 2 +
#     / \
#    3   4
t = Tree('*', [Tree('1'),
               Tree('+', [Tree('3'),

How to Automatically Start a Download in PHP?

Here is an example of sending back a pdf.

header('Content-type: application/pdf');
header('Content-Disposition: attachment; filename="' . basename($filename) . '"');
header('Content-Transfer-Encoding: binary');

@Swish I didn't find application/force-download content type to do anything different (tested in IE and Firefox). Is there a reason for not sending back the actual MIME type?

Also in the PHP manual Hayley Watson posted:

If you wish to force a file to be downloaded and saved, instead of being rendered, remember that there is no such MIME type as "application/force-download". The correct type to use in this situation is "application/octet-stream", and using anything else is merely relying on the fact that clients are supposed to ignore unrecognised MIME types and use "application/octet-stream" instead (reference: Sections 4.1.4 and 4.5.1 of RFC 2046).

Also according IANA there is no registered application/force-download type.

phpMyAdmin - configuration?

I found that the new version of PhpMyAdmin put the '' files in /var/lib/phpmyadmin/

I spend much time in the wrong dir (/usr/share) as this is where all the files also is located, but changes are not reflected.

After putting my settings in


They worked

json_encode function: special characters

Your input has to be encoded as UTF-8 or ISO-8859-1.

Because if you try to convert an array of non-utf8 characters you'll be getting 0 as return value.

Since 5.5.0 The return value on failure was changed from null string to FALSE.

How to select unique records by SQL

It depends on which rown you want to return for each unique item. Your data seems to indicate the minimum data value so in this instance for SQL Server.

SELECT item, min(data)
FROM  table

Check if space is in a string

Use this:

word = raw_input("Please enter a single word : ")
while True:
    if " " in word:
        word = raw_input("Please enter a single word : ")
        print "Thanks"

grabbing first row in a mysql query only

You can get the total number of rows containing a specific name using:

SELECT COUNT(*) FROM tbl_foo WHERE name = 'sarmen'

Given the count, you can now get the nth row using:

SELECT * FROM tbl_foo WHERE name = 'sarmen' LIMIT (n - 1), 1

Where 1 <= n <= COUNT(*) from the first query.


getting the 3rd row

SELECT * FROM tbl_foo WHERE name = 'sarmen' LIMIT 2, 1

Does a "Find in project..." feature exist in Eclipse IDE?

1. Ctrl + H
2. Choose File Search for plain text search in workspace/selected projects

For specific expression searches, choose the relevant tab (such as Java Search which allows you to search for specific identifiers)

For whole project search:

3. Scope (in the form section) > Enclosing project (Radio button selection).

Apply pandas function to column to create multiple new columns?

I've looked several ways of doing this and the method shown here (returning a pandas series) doesn't seem to be most efficient.

If we start with a largeish dataframe of random data:

# Setup a dataframe of random numbers and create a 
df = pd.DataFrame(np.random.randn(10000,3),columns=list('ABC'))
df['D'] = df.apply(lambda r: ':'.join(map(str, (r.A, r.B, r.C))), axis=1)
columns = 'new_a', 'new_b', 'new_c'

The example shown here:

# Create the dataframe by returning a series
def method_b(v):
    return pd.Series({k: v for k, v in zip(columns, v.split(':'))})
%timeit -n10 -r3 df.D.apply(method_b)

10 loops, best of 3: 2.77 s per loop

An alternative method:

# Create a dataframe from a series of tuples
def method_a(v):
    return v.split(':')
%timeit -n10 -r3 pd.DataFrame(df.D.apply(method_a).tolist(), columns=columns)

10 loops, best of 3: 8.85 ms per loop

By my reckoning it's far more efficient to take a series of tuples and then convert that to a DataFrame. I'd be interested to hear people's thinking though if there's an error in my working.

entity framework Unable to load the specified metadata resource

Craig Stuntz has written an extensive (in my opinion) blog post on troubleshooting this exact error message, I personally would start there.

The following res: (resource) references need to point to your model.

<add name="Entities" connectionString="metadata=

Make sure each one has the name of your .edmx file after the "*/", with the "edmx" changed to the extension for that res (.csdl, .ssdl, or .msl).

It also may help to specify the assembly rather than using "//*/".

Worst case, you can check everything (a bit slower but should always find the resource) by using

<add name="Entities" connectionString="metadata=
        res://*/;provider= <!-- ... -->

Why cannot change checkbox color whatever I do?

Yes, you can. Based on knowledge from colleagues here and researching on web, here you have the best solution for styling a checkbox without any third-party plugin:

  width: 14px !important;
  height: 14px !important;
  margin: 5px;
  -webkit-appearance: none;
  -moz-appearance: none;
  -o-appearance: none;
  appearance: none;
  outline: 1px solid gray;
  box-shadow: none;
  font-size: 0.8em;
  text-align: center;
  line-height: 1em;
  background: red;

input[type='checkbox']:checked:after {
  content: '?';
  color: white;
<input type='checkbox'>

Two column div layout with fluid left and fixed right column

The following examples are source ordered i.e. column 1 appears before column 2 in the HTML source. Whether a column appears on left or right is controlled by CSS:

Fixed Right

#wrapper {_x000D_
  margin-right: 200px;_x000D_
#content {_x000D_
  float: left;_x000D_
  width: 100%;_x000D_
  background-color: #CCF;_x000D_
#sidebar {_x000D_
  float: right;_x000D_
  width: 200px;_x000D_
  margin-right: -200px;_x000D_
  background-color: #FFA;_x000D_
#cleared {_x000D_
  clear: both;_x000D_
<div id="wrapper">_x000D_
  <div id="content">Column 1 (fluid)</div>_x000D_
  <div id="sidebar">Column 2 (fixed)</div>_x000D_
  <div id="cleared"></div>_x000D_

Fixed Left

#wrapper {_x000D_
  margin-left: 200px;_x000D_
#content {_x000D_
  float: right;_x000D_
  width: 100%;_x000D_
  background-color: #CCF;_x000D_
#sidebar {_x000D_
  float: left;_x000D_
  width: 200px;_x000D_
  margin-left: -200px;_x000D_
  background-color: #FFA;_x000D_
#cleared {_x000D_
  clear: both;_x000D_
<div id="wrapper">_x000D_
  <div id="content">Column 1 (fluid)</div>_x000D_
  <div id="sidebar">Column 2 (fixed)</div>_x000D_
  <div id="cleared"></div>_x000D_

Alternate solution is to use display: table-cell; which results in equal height columns.

How do I export html table data as .csv file?

The following solution can do it.

$(function() {_x000D_
  $("button").on('click', function() {_x000D_
    var data = "";_x000D_
    var tableData = [];_x000D_
    var rows = $("table tr");_x000D_
    rows.each(function(index, row) {_x000D_
      var rowData = [];_x000D_
      $(row).find("th, td").each(function(index, column) {_x000D_
    data += tableData.join("\n");_x000D_
    $(document.body).append('<a id="download-link" download="data.csv" href=' + URL.createObjectURL(new Blob([data], {_x000D_
      type: "text/csv"_x000D_
    })) + '/>');_x000D_
table {_x000D_
  border-collapse: collapse;_x000D_
th {_x000D_
  border: 1px solid #aaa;_x000D_
  padding: 0.5rem;_x000D_
  text-align: left;_x000D_
td {_x000D_
  font-size: 0.875rem;_x000D_
.btn-group {_x000D_
  padding: 1rem 0;_x000D_
button {_x000D_
  background-color: #fff;_x000D_
  border: 1px solid #000;_x000D_
  margin-top: 0.5rem;_x000D_
  border-radius: 3px;_x000D_
  padding: 0.5rem 1rem;_x000D_
  font-size: 1rem;_x000D_
button:hover {_x000D_
  cursor: pointer;_x000D_
  background-color: #000;_x000D_
  color: #fff;_x000D_
<script src=""></script>_x000D_
      <td>John Resig</td>_x000D_
      <td>The Write Less, Do More, JavaScript Library.</td>_x000D_
      <td>Jordan Walke</td>_x000D_
      <td>React makes it painless to create interactive UIs.</td>_x000D_
      <td>Yuxi You</td>_x000D_
      <td>The Progressive JavaScript Framework.</td>_x000D_
<div class="btn-group">_x000D_

How to preventDefault on anchor tags?

An alternative might be:

<span ng-click="do()">Click</span>

How to create a BKS (BouncyCastle) format Java Keystore that contains a client certificate chain

I don't think your problem is with the BouncyCastle keystore; I think the problem is with a broken package in Android. The BouncyCastle keystore is a supreme annoyance because Android changed a default Java behavior without documenting it anywhere -- and removed the default provider -- but it does work.

Note that for SSL authentication you may require 2 keystores. The "TrustManager" keystore, which contains the CA certs, and the "KeyManager" keystore, which contains your client-site public/private keys. (The documentation is somewhat vague on what needs to be in the KeyManager keystore.) In theory, you shouldn't need the TrustManager keystore if all of your certficates are signed by "well-known" Certifcate Authorities, e.g., Verisign, Thawte, and so on. Let me know how that works for you. Your server will also require the CA for whatever was used to sign your client.

I could not create an SSL connection using at all. I disabled the client SSL authentication on the server side, and I still could not create the connection. Since my end goal was an HTTPS GET, I punted and tried using the Apache HTTP Client that's bundled with Android. That sort-of worked. I could make the HTTPS conection, but I still could not use SSL auth. If I enabled the client SSL authentication on my server, the connection would fail. I haven't checked the Apache HTTP Client code, but I suspect they are using their own SSL implementation, and don't use

Creating and throwing new exception

You can throw your own custom errors by extending the Exception class.

class CustomException : Exception {
    [string] $additionalData

    CustomException($Message, $additionalData) : base($Message) {
        $this.additionalData = $additionalData

try {
    throw [CustomException]::new('Error message', 'Extra data')
} catch [CustomException] {
    # NOTE: To access your custom exception you must use $_.Exception
    Write-Output $_.Exception.additionalData

    # This will produce the error message: Didn't catch it the second time
    throw [CustomException]::new("Didn't catch it the second time", 'Extra data')

Convert date formats in bash

If you would like a bash function that works both on Mac OS X and Linux:

# Convert one date format to another
# Usage: convert_date_format <input_format> <date> <output_format>
# Example: convert_date_format '%b %d %T %Y %Z' 'Dec 10 17:30:05 2017 GMT' '%Y-%m-%d'
convert_date_format() {
  local INPUT_FORMAT="$1"
  local INPUT_DATE="$2"
  local OUTPUT_FORMAT="$3"
  local UNAME=$(uname)

  if [[ "$UNAME" == "Darwin" ]]; then
    # Mac OS X
  elif [[ "$UNAME" == "Linux" ]]; then
    # Linux
    date -d "$INPUT_DATE" +"$OUTPUT_FORMAT"
    # Unsupported system
    echo "Unsupported system"

# Example: 'Dec 10 17:30:05 2017 GMT' => '2017-12-10'
convert_date_format '%b %d %T %Y %Z' 'Dec 10 17:30:05 2017 GMT' '%Y-%m-%d'

Copy and paste content from one file to another file in vi

My scenario was I need to copy n number of lines in middle, n unknown, from file 1 to file 2.

:'a,'bw /name/of/output/file.txt

changing source on html5 video tag

I solved this with this simple method

function changeSource(url) {
   var video = document.getElementById('video');
   video.src = url;;

ignoring any 'bin' directory on a git project

I think it is worth to mention for git beginners:

If you already have a file checked in, and you want to ignore it, Git will not ignore the file if you add a rule later. In those cases, you must untrack the file first, by running the following command in your terminal:

git rm --cached

So if you want add to ignore some directories in your local repository (which already exist) after editing .gitignore you want to run this on your root dir

git rm --cached -r .
git add .

It will basically 'refresh' your local repo and unstage ignored files.


Can scrapy be used to scrape dynamic content from websites that are using AJAX?

how can scrapy be used to scrape this dynamic data so that I can use it?

I wonder why no one has posted the solution using Scrapy only.

Check out the blog post from Scrapy team SCRAPING INFINITE SCROLLING PAGES . The example scraps website which uses infinite scrolling.

The idea is to use Developer Tools of your browser and notice the AJAX requests, then based on that information create the requests for Scrapy.

import json
import scrapy

class SpidyQuotesSpider(scrapy.Spider):
    name = 'spidyquotes'
    quotes_base_url = ''
    start_urls = [quotes_base_url % 1]
    download_delay = 1.5

    def parse(self, response):
        data = json.loads(response.body)
        for item in data.get('quotes', []):
            yield {
                'text': item.get('text'),
                'author': item.get('author', {}).get('name'),
                'tags': item.get('tags'),
        if data['has_next']:
            next_page = data['page'] + 1
            yield scrapy.Request(self.quotes_base_url % next_page)

How to get the first element of an array?

Why not account for times your array might be empty?

var ary = ['first', 'second', 'third', 'fourth', 'fifth'];
first = (array) => array.length ? array[0] : 'no items';
// output: first

var ary = [];
// output: no items

@JsonProperty annotation on field as well as getter/setter

My observations based on a few tests has been that whichever name differs from the property name is one which takes effect:

For eg. consider a slight modification of your case:

private String fileName;

public String getFileName()
    return fileName;

public void setFileName(String fileName)
    this.fileName = fileName;

Both fileName field, and method getFileName, have the correct property name of fileName and setFileName has a different one fileName1, in this case Jackson will look for a fileName1 attribute in json at the point of deserialization and will create a attribute called fileName1 at the point of serialization.

Now, coming to your case, where all the three @JsonProperty differ from the default propertyname of fileName, it would just pick one of them as the attribute(FILENAME), and had any on of the three differed, it would have thrown an exception:

java.lang.IllegalStateException: Conflicting property name definitions

Change Project Namespace in Visual Studio

"Default Namespace textbox in project properties is disabled" Same with me (VS 2010). I edited the project file ("xxx.csproj") and tweaked the item. That changed the default namespace.

OpenSSL: PEM routines:PEM_read_bio:no start line:pem_lib.c:703:Expecting: TRUSTED CERTIFICATE

My situation was a little different. The solution was to strip the .pem from everything outside of the CERTIFICATE and PRIVATE KEY sections and to invert the order which they appeared. After converting from pfx to pem file, the certificate looked like this:

Bag Attributes
localKeyID: ...
Bag Attributes
more garbage...

After correcting the file, it was just:


Display / print all rows of a tibble (tbl_df)

i prefer to physically print my tables instead:


data.frame = data.frame(1:1000, 1000:2)

connectServer <- Sys.getenv("CONNECT_SERVER")
apiKey <- Sys.getenv("CONNECT_API_KEY")


print2print::send2printer(connectServer, apiKey, data.frame)

How can I clear or empty a StringBuilder?

I'll vote for sb.setLength(0); not only because it's one function call, but because it doesn't actually copy the array into another array like sb.delete(0, builder.length());. It just fill the remaining characters to be 0 and set the length variable to the new length.

You can take a look into their implementation to validate my point from here at setLength function and delete0 function.

Return row number(s) for a particular value in a column in a dataframe

Use which(mydata_2$height_chad1 == 2585)

Short example

df <- data.frame(x = c(1,1,2,3,4,5,6,3),
                 y = c(5,4,6,7,8,3,2,4))
  x y
1 1 5
2 1 4
3 2 6
4 3 7
5 4 8
6 5 3
7 6 2
8 3 4

which(df$x == 3)
[1] 4 8

length(which(df$x == 3))
[1] 2

count(df, vars = "x")
  x freq
1 1    2
2 2    1
3 3    2
4 4    1
5 5    1
6 6    1

df[which(df$x == 3),]
  x y
4 3 7
8 3 4

As Matt Weller pointed out, you can use the length function. The count function in plyr can be used to return the count of each unique column value.

Function pointer as a member of a C struct

You can use also "void*" (void pointer) to send an address to the function.

typedef struct pstring_t {
    char * chars;
} PString;

int length(void* self) {
    return strlen(((PString*)self)->chars);

PString initializeString() {
    PString str;
    str.length = &length;
    return str;

int main()
    PString p = initializeString();

    p.chars = "Hello";

    printf("Length: %i\n", p.length(&p));

    return 0;


Length: 5

Prevent Android activity dialog from closing on outside touch

I was facing the same problem. To handle it I set a OntouchListener to the dialog and do nothing inside. But Dialog dismiss when rotating screen too. To fix it I set a variable to tell me if the dialog has normally dismissed. Then I set a OnDismissListener to my dialog and inside I check the variable. If the dialog has dismmiss normally I do nothin, or else I run the dialog again (and setting his state as when dismissing in my case).

How to center cell contents of a LaTeX table whose columns have fixed widths?

\usepackage{array} in the preamble

then this:

\begin{tabular}{| >{\centering\arraybackslash}m{1in} | >{\centering\arraybackslash}m{1in} |}

note that the "m" for fixed with column is provided by the array package, and will give you vertical centering (if you don't want this just go back to "p"

Concatenate multiple result rows of one column into one, group by another column

You can use array_agg function for that:

SELECT "Movie",
array_to_string(array_agg(distinct "Actor"),',') AS Actor
FROM Table1
GROUP BY "Movie";


A 1,2,3
B 4

See this SQLFiddle

For more See 9.18. Aggregate Functions

One liner for If string is not null or empty else

You can write your own Extension method for type String :-

 public static string NonBlankValueOf(this string source)
    return (string.IsNullOrEmpty(source)) ? "0" : source;

Now you can use it like with any string type

FooTextBox.Text = strFoo.NonBlankValueOf();