Programs & Examples On #Aesthetics

Aes, short for "aesthetics" is an R Library, used to "Generate aesthetic mappings that describe how variables in the data are mapped to visual properties (aesthetics) of geoms." The aesthetics tag should **not** be used to reference software's artistic merit.

Aesthetics must either be length one, or the same length as the dataProblems

I encountered this problem because the dataset was filtered wrongly and the resultant data frame was empty. Even the following caused the error to show:

ggplot(df, aes(x="", y = y, fill=grp))

because df was empty.

Format of the initialization string does not conform to specification starting at index 0

I had this error and it turned out that the cause was that I had surrounded a (new) tableadapter with a Using/End Using. Just changing the tableadapter to stay live for longer (duration of class in my instance) fixed this for me. Maybe this will help someone.

Javascript set img src

If you're using WinJS you can change the src through the Utilities functions.

WinJS.Utilities.id("pic1").setAttribute("src", searchPic.src);

What are the best use cases for Akka framework

I have used it so far in two real projects very successfully. both are in the near real-time traffic information field (traffic as in cars on highways), distributed over several nodes, integrating messages between several parties, reliable backend systems. I'm not at liberty to give specifics on clients yet, when I do get the OK maybe it can be added as a reference.

Akka has really pulled through on those projects, even though we started when it was on version 0.7. (we are using scala by the way)

One of the big advantages is the ease at which you can compose a system out of actors and messages with almost no boilerplating, it scales extremely well without all the complexities of hand-rolled threading and you get asynchronous message passing between objects almost for free.

It is very good in modeling any type of asynchronous message handling. I would prefer to write any type of (web) services system in this style than any other style. (Have you ever tried to write an asynchronous web service (server side) with JAX-WS? that's a lot of plumbing). So I would say any system that does not want to hang on one of its components because everything is implicitly called using synchronous methods, and that one component is locking on something. It is very stable and the let-it-crash + supervisor solution to failure really works well. Everything is easy to setup programmatically and not hard to unit test.

Then there are the excellent add-on modules. The Camel module really plugs in well into Akka and enables such easy development of asynchronous services with configurable endpoints.

I'm very happy with the framework and it is becoming a defacto standard for the connected systems that we build.

How to change btn color in Bootstrap

Just create your own button on:

Cheers

css to make bootstrap navbar transparent

CSS code:

.header .navbar-default {
  background: none;
}

HTML code:

<header>
    <nav class="navbar navbar-default"></nav>
</header>

How to find out whether a file is at its `eof`?

You can use below code snippet to read line by line, till end of file:

line = obj.readline()
while(line != ''):
    # Do Something
    line = obj.readline()

IF formula to compare a date with current date and return result

I think this will cover any possible scenario for what is in O10:

=IF(ISBLANK(O10),"",IF(O10<TODAY(),IF(TODAY()-O10<>1,CONCATENATE("Due in ",TEXT(TODAY()-O10,"d")," days"),CONCATENATE("Due in ",TEXT(TODAY()-O10,"d")," day")),IF(O10=TODAY(),"Due Today","Overdue")))

For Dates that are before Today, it will tell you how many days the item is due in. If O10 = Today then it will say "Due Today". Anything past Today and it will read overdue. Lastly, if it is blank, the cell will also appear blank. Let me know what you think!

How to hide first section header in UITableView (grouped style)

Swift3 : heightForHeaderInSection works with 0, you just have to make sure header is set to clipsToBounds.

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
       return 0
}

if you don't set clipsToBounds hidden header will be visible when scrolling.

func tableView(_ tableView: UITableView, willDisplayHeaderView view: UIView, forSection section: Int) {
    guard let header = view as? UITableViewHeaderFooterView else { return }

    header.clipsToBounds = true
}

pthread function from a class

C++ : How to pass class member function to pthread_create()?

http://thispointer.com/c-how-to-pass-class-member-function-to-pthread_create/

typedef void * (*THREADFUNCPTR)(void *);

class C { 
   // ...
   void *print(void *) { cout << "Hello"; }
}

pthread_create(&threadId, NULL, (THREADFUNCPTR) &C::print, NULL);

How to check if command line tools is installed

Go to Applications > Xcode > preferences > downloads

You should see the command line tools there for you to install.

'cannot find or open the pdb file' Visual Studio C++ 2013

Working with VS 2013. Try the following

Tools -> Options -> Debugging -> Output Window -> Module Load Messages -> Off

It will disable the display of modules loaded.

Docker-Compose persistent data MySQL

Actually this is the path and you should mention a valid path for this to work. If your data directory is in current directory then instead of my-data you should mention ./my-data, otherwise it will give you that error in mysql and mariadb also.

volumes:
 ./my-data:/var/lib/mysql

jQuery get the location of an element relative to window

This sounds more like you want a tooltip for the link selected. There are many jQuery tooltips, try out jQuery qTip. It has a lot of options and is easy to change the styles.

Otherwise if you want to do this yourself you can use the jQuery .position(). More info about .position() is on http://api.jquery.com/position/

$("#element").position(); will return the current position of an element relative to the offset parent.

There is also the jQuery .offset(); which will return the position relative to the document.

How to know what the 'errno' means?

Call

perror("execl");

in case of error.

Sample:

if(read(fd, buf, 1)==-1) {
    perror("read");
}

The manpages of errno(3) and perror(3) are interesting, too...

enabling cross-origin resource sharing on IIS7

With ASP.net Web API 2 install Microsoft ASP.NET Cross Origin support via nuget.

http://enable-cors.org/server_aspnet.html

public static void Register(HttpConfiguration config)
{
 var enableCorsAttribute = new EnableCorsAttribute("http://mydomain.com",
                                                   "Origin, Content-Type, Accept",
                                                   "GET, PUT, POST, DELETE, OPTIONS");
        config.EnableCors(enableCorsAttribute);
}

Build Step Progress Bar (css and jquery)

This is what I did:

  1. Create jQuery .progressbar() to load a div into a progress bar.
  2. Create the step title on the bottom of the progress bar. Position them with CSS.
  3. Then I create function in jQuery that change the value of the progressbar everytime user move on to next step.

HTML

<div id="divProgress"></div>
<div id="divStepTitle">
    <span class="spanStep">Step 1</span> <span class="spanStep">Step 2</span> <span class="spanStep">Step 3</span>
</div>

<input type="button" id="btnPrev" name="btnPrev" value="Prev" />
<input type="button" id="btnNext" name="btnNext" value="Next" />

CSS

#divProgress
{
    width: 600px;
}

#divStepTitle
{
    width: 600px;
}

.spanStep
{
    text-align: center;
    width: 200px;
}

Javascript/jQuery

var progress = 0;

$(function({
    //set step progress bar
    $("#divProgress").progressbar();

    //event handler for prev and next button
    $("#btnPrev, #btnNext").click(function(){
        step($(this));
    });
});

function step(obj)
{
    //switch to prev/next page
    if (obj.val() == "Prev")
    {
        //set new value for progress bar
        progress -= 20;
        $("#divProgress").progressbar({ value: progress });

        //do extra step for showing previous page
    }
    else if (obj.val() == "Next")
    {
        //set new value for progress bar
        progress += 20;
        $("#divProgress").progressbar({ value: progress });

        //do extra step for showing next page
    }
}

How to len(generator())

You can use reduce.

For Python 3:

>>> import functools
>>> def gen():
...     yield 1
...     yield 2
...     yield 3
...
>>> functools.reduce(lambda x,y: x + 1, gen(), 0)

In Python 2, reduce is in the global namespace so the import is unnecessary.

Where is the user's Subversion config file stored on the major operating systems?

~/.subversion/config or /etc/subversion/config

for Mac/Linux

and

%appdata%\subversion\config

for Windows

Clicking URLs opens default browser

in some cases you might need an override of onLoadResource if you get a redirect which doesn't trigger the url loading method. in this case i tried the following:

@Override
public void onLoadResource(WebView view, String url)
{
    if (url.equals("http://redirectexample.com"))
    {
        //do your own thing here
    }
    else
    {
        super.onLoadResource(view, url);
    }           
}

What is the difference between .NET Core and .NET Standard Class Library project types?

A .NET Core Class Library is built upon the .NET Standard. If you want to implement a library that is portable to the .NET Framework, .NET Core and Xamarin, choose a .NET Standard Library

.NET Core will ultimately implement .NET Standard 2 (as will Xamarin and .NET Framework)

.NET Core, Xamarin and .NET Framework can, therefore, be identified as flavours of .NET Standard

To future-proof your applications for code sharing and reuse, you would rather implement .NET Standard libraries.

Microsoft also recommends that you use .NET Standard instead of Portable Class Libraries.

To quote MSDN as an authoritative source, .NET Standard is intended to be One Library to Rule Them All. As pictures are worth a thousand words, the following will make things very clear:

1. Your current application scenario (fragmented)

Like most of us, you are probably in the situation below: (.NET Framework, Xamarin and now .NET Core flavoured applications)

Enter image description here

2. What the .NET Standard Library will enable for you (cross-framework compatibility)

Implementing a .NET Standard Library allows code sharing across all these different flavours:

One Library to Rule them All

For the impatient:

  1. .NET Standard solves the code sharing problem for .NET developers across all platforms by bringing all the APIs that you expect and love across the environments that you need: desktop applications, mobile apps & games, and cloud services:
  2. .NET Standard is a set of APIs that all .NET platforms have to implement. This unifies the .NET platforms and prevents future fragmentation.
  3. .NET Standard 2.0 will be implemented by .NET Framework, .NET Core, and Xamarin. For .NET Core, this will add many of the existing APIs that have been requested.
  4. .NET Standard 2.0 includes a compatibility shim for .NET Framework binaries, significantly increasing the set of libraries that you can reference from your .NET Standard libraries.
  5. .NET Standard will replace Portable Class Libraries (PCLs) as the tooling story for building multi-platform .NET libraries.

For a table to help understand what the highest version of .NET Standard that you can target, based on which .NET platforms you intend to run on, head over here.

Sources: MSDN: Introducing .NET Standard

Convert a list to a string in C#

If you're looking to turn the items in a list into a big long string, do this: String.Join("", myList). Some older versions of the framework don't allow you to pass an IEnumerable as the second parameter, so you may need to convert your list to an array by calling .ToArray().

What is the difference between baud rate and bit rate?

Bit per second is what is means - rate of data transmission of ones and zeros per second are used.This is called bit per second(bit/s. However, it should not be confused with bytes per second, abbreviated as bytes/s, Bps, or B/s.

Raw throughput values are normally given in bits per second, but many software applications report transfer rates in bytes per second.

So, the standard unit for bit throughput is the bit per second, which is commonly abbreviated bit/s, bps, or b/s.

Baud is a unit of measure of changes , or transitions , that occurs in a signal in each second.

For example if the signal changes from one value to a zero value(or vice versa) one hundred times per second, that is a rate of 100 baud.

The other one measures data(the throughput of channel), and the other ones measures transitions(called signalling rates).

For example if you look at modern modems they use advanced modulation techniques that encoded more than one bit of data into each transition.

Thanks.

Uncaught SyntaxError: Unexpected token u in JSON at position 0

For me, that happened because I had an empty component in my page -

<script type="text/x-magento-init">
   {
   ".page.messages": {
       "Magento_Ui/js/core/app": []        
      }
   }

Deleting this piece of code resolved the issue.

How do I implement a callback in PHP?

With PHP 5.3, you can now do this:

function doIt($callback) { $callback(); }

doIt(function() {
    // this will be done
});

Finally a nice way to do it. A great addition to PHP, because callbacks are awesome.

How to change symbol for decimal point in double.ToString()?

Convert.ToString(value, CultureInfo.InvariantCulture);

How to serialize a JObject without the formatting?

You can also do the following;

string json = myJObject.ToString(Newtonsoft.Json.Formatting.None);

Is there a way to iterate over a dictionary?

Yes, NSDictionary supports fast enumeration. With Objective-C 2.0, you can do this:

// To print out all key-value pairs in the NSDictionary myDict
for(id key in myDict)
    NSLog(@"key=%@ value=%@", key, [myDict objectForKey:key]);

The alternate method (which you have to use if you're targeting Mac OS X pre-10.5, but you can still use on 10.5 and iPhone) is to use an NSEnumerator:

NSEnumerator *enumerator = [myDict keyEnumerator];
id key;
// extra parens to suppress warning about using = instead of ==
while((key = [enumerator nextObject]))
    NSLog(@"key=%@ value=%@", key, [myDict objectForKey:key]);

How to make an anchor tag refer to nothing?

<a href="#" onclick="SomeFunction()"  class="SomeClass">sth.</a>

this was my anchor tag. so return false on onClick="" event is not usefull here. I just removed href="#" property and it worked for me just like below

<a onclick="SomeFunction()"  class="SomeClass">sth.</a>

and i needed to add this css.

.SomeClass
{
    cursor: pointer;
}

How to update a menu item shown in the ActionBar?

I have used this code:

public boolean onPrepareOptionsMenu (Menu menu) {       
    MenuInflater inflater = getMenuInflater();
    TextView title  = (TextView) findViewById(R.id.title);
    menu.getItem(0).setTitle(
        getString(R.string.payFor) + " " + title.getText().toString());
    menu.getItem(1).setTitle(getString(R.string.payFor) + "...");
    return true;        
}

And worked like a charm to me you can find OnPrepareOptionsMenu here

React-Redux: Actions must be plain objects. Use custom middleware for async actions

For future seekers who might have dropped simple details like me, in my case I just have forgotten to call my action function with parentheses.

actions.js:

export function addNewComponent() {
  return {
    type: ADD_NEW_COMPONENT,
  };
}

myComponent.js:

import React, { useEffect } from 'react';
import { addNewComponent } from '../../redux/actions';

  useEffect(() => {
    dispatch(refreshAllComponents); // <= Here was what I've missed.
  }, []);

I've forgotten to dispatch the action function with (). So doing this solved my issue.

  useEffect(() => {
    dispatch(refreshAllComponents());
  }, []);

Again this might have nothing to do with OP's problem, but I hope I helps people with the same problem as mine.

StringStream in C#

You have a number of options:

One is to not use streams, but use the TextWriter

   void Print(TextWriter writer) 
   {
   }

   void Main() 
  {
    var textWriter = new StringWriter();
    Print(writer);
    string myString = textWriter.ToString();
   }

It's likely that TextWriter is the appropriate level of abstraction for your print function. Streams are aimed at writing binary data, while TextWriter works at a higher abstraction level, specifically geared towards outputting strings.

If your motivation is that you also want your Print function to write to files, you can get a text writer from a filestream as well.

void Print(TextWriter writer) 
{
}

void PrintToFile(string filePath) 
{
     using(var textWriter = new StreamWriter(filePath))
     {
         Print(writer);
     }
}

If you REALLY want a stream you can look at MemoryStream.

No Access-Control-Allow-Origin header is present on the requested resource

You are missing 'json' dataType in the $.post() method:

$.post('http://www.example.com:PORT_NUMBER/MYSERVLET',{MyParam: 'value'})
        .done(function(data){
                  alert(data);
         }, "json");
         //-^^^^^^-------here

Updates:

try with this:

response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));

C++ templates that accept only certain types

As far as I know this isn't currently possible in C++. However, there are plans to add a feature called "concepts" in the new C++0x standard that provide the functionality that you're looking for. This Wikipedia article about C++ Concepts will explain it in more detail.

I know this doesn't fix your immediate problem but there are some C++ compilers that have already started to add features from the new standard, so it might be possible to find a compiler that has already implemented the concepts feature.

How to capture a list of specific type with mockito

Based on @tenshi's and @pkalinow's comments (also kudos to @rogerdpack), the following is a simple solution for creating a list argument captor that also disables the "uses unchecked or unsafe operations" warning:

@SuppressWarnings("unchecked")
final ArgumentCaptor<List<SomeType>> someTypeListArgumentCaptor =
    ArgumentCaptor.forClass(List.class);

Full example here and corresponding passing CI build and test run here.

Our team has been using this for some time in our unit tests and this looks like the most straightforward solution for us.

How do I compile a .c file on my Mac?

Use the gcc compiler. This assumes that you have the developer tools installed.

How to convert DATE to UNIX TIMESTAMP in shell script on MacOS

I wrote a set of scripts that provides a uniform interface for both BSD and GNU version of date.

Follow command will output the Epoch seconds for the date 2010-10-02, and it works with both BSD and GNU version of date.

$ xsh /date/convert "2010-10-02" "+%s"
1286020263

It's an equivalent of the command with GNU version of date:

date -d "2010-10-02" "+%s"

and also the command with BSD version of date:

date -j -f "%F" 2010-10-02 "+%s"

The scripts can be found at:

It's a part of a library called xsh-lib/core. To use them you need both repos xsh and xsh-lib/core, I list them below:

How to update two tables in one statement in SQL Server 2005?

You should place two update statements inside a transaction

AddTransient, AddScoped and AddSingleton Services Differences

After looking for an answer for this question I found a brilliant explanation with an example that I would like to share with you.

You can watch a video that demonstrate the differences HERE

In this example we have this given code:

public interface IEmployeeRepository
{
    IEnumerable<Employee> GetAllEmployees();
    Employee Add(Employee employee);
}

public class Employee
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class MockEmployeeRepository : IEmployeeRepository
{
    private List<Employee> _employeeList;

    public MockEmployeeRepository()
    {
        _employeeList = new List<Employee>()
    {
        new Employee() { Id = 1, Name = "Mary" },
        new Employee() { Id = 2, Name = "John" },
        new Employee() { Id = 3, Name = "Sam" },
    };
    }

    public Employee Add(Employee employee)
    {
        employee.Id = _employeeList.Max(e => e.Id) + 1;
        _employeeList.Add(employee);
        return employee;
    }

    public IEnumerable<Employee> GetAllEmployees()
    {
        return _employeeList;
    }
}

HomeController

public class HomeController : Controller
{
    private IEmployeeRepository _employeeRepository;

    public HomeController(IEmployeeRepository employeeRepository)
    {
        _employeeRepository = employeeRepository;
    }

    [HttpGet]
    public ViewResult Create()
    {
        return View();
    }

    [HttpPost]
    public IActionResult Create(Employee employee)
    {
        if (ModelState.IsValid)
        {
            Employee newEmployee = _employeeRepository.Add(employee);
        }

        return View();
    }
}

Create View

@model Employee
@inject IEmployeeRepository empRepository

<form asp-controller="home" asp-action="create" method="post">
    <div>
        <label asp-for="Name"></label>
        <div>
            <input asp-for="Name">
        </div>
    </div>

    <div>
        <button type="submit">Create</button>
    </div>

    <div>
        Total Employees Count = @empRepository.GetAllEmployees().Count().ToString()
    </div>
</form>

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddSingleton<IEmployeeRepository, MockEmployeeRepository>();
}

Copy-paste this code and press on the create button in the view and switch between AddSingleton , AddScoped and AddTransient you will get each time a different result that will might help you understand this.

AddSingleton() - As the name implies, AddSingleton() method creates a Singleton service. A Singleton service is created when it is first requested. This same instance is then used by all the subsequent requests. So in general, a Singleton service is created only one time per application and that single instance is used throughout the application life time.

AddTransient() - This method creates a Transient service. A new instance of a Transient service is created each time it is requested.

AddScoped() - This method creates a Scoped service. A new instance of a Scoped service is created once per request within the scope. For example, in a web application it creates 1 instance per each http request but uses the same instance in the other calls within that same web request.

Check if not nil and not empty in Rails shortcut?

There's a method that does this for you:

def show
  @city = @user.city.present?
end

The present? method tests for not-nil plus has content. Empty strings, strings consisting of spaces or tabs, are considered not present.

Since this pattern is so common there's even a shortcut in ActiveRecord:

def show
  @city = @user.city?
end

This is roughly equivalent.

As a note, testing vs nil is almost always redundant. There are only two logically false values in Ruby: nil and false. Unless it's possible for a variable to be literal false, this would be sufficient:

if (variable)
  # ...
end

This is preferable to the usual if (!variable.nil?) or if (variable != nil) stuff that shows up occasionally. Ruby tends to wards a more reductionist type of expression.

One reason you'd want to compare vs. nil is if you have a tri-state variable that can be true, false or nil and you need to distinguish between the last two states.

matplotlib colorbar in each subplot

This can be easily solved with the the utility make_axes_locatable. I provide a minimal example that shows how this works and should be readily adaptable:

bar to each image

import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable

import numpy as np

m1 = np.random.rand(3, 3)
m2 = np.arange(0, 3*3, 1).reshape((3, 3))

fig = plt.figure(figsize=(16, 12))
ax1 = fig.add_subplot(121)
im1 = ax1.imshow(m1, interpolation='None')

divider = make_axes_locatable(ax1)
cax = divider.append_axes('right', size='5%', pad=0.05)
fig.colorbar(im1, cax=cax, orientation='vertical')

ax2 = fig.add_subplot(122)
im2 = ax2.imshow(m2, interpolation='None')

divider = make_axes_locatable(ax2)
cax = divider.append_axes('right', size='5%', pad=0.05)
fig.colorbar(im2, cax=cax, orientation='vertical');

Create Generic method constraining T to an Enum

As stated in other answers before; while this cannot be expressed in source-code it can actually be done on IL Level. @Christopher Currens answer shows how the IL do to that.

With Fodys Add-In ExtraConstraints.Fody there's a very simple way, complete with build-tooling, to achieve this. Just add their nuget packages (Fody, ExtraConstraints.Fody) to your project and add the constraints as follows (Excerpt from the Readme of ExtraConstraints):

public void MethodWithEnumConstraint<[EnumConstraint] T>() {...}

public void MethodWithTypeEnumConstraint<[EnumConstraint(typeof(ConsoleColor))] T>() {...}

and Fody will add the necessary IL for the constraint to be present. Also note the additional feature of constraining delegates:

public void MethodWithDelegateConstraint<[DelegateConstraint] T> ()
{...}

public void MethodWithTypeDelegateConstraint<[DelegateConstraint(typeof(Func<int>))] T> ()
{...}

Regarding Enums, you might also want to take note of the highly interesting Enums.NET.

SQLAlchemy: What's the difference between flush() and commit()?

Use flush when you need to write, for example to get a primary key ID from an autoincrementing counter.

john=Person(name='John Smith', parent=None)
session.add(john)
session.flush()

son=Person(name='Bill Smith', parent=john.id)

Without flushing, john would never get an ID from the DB and so couldn't represent the parent/child relationship in code.

Like others have said, without commit() none of this will be permanently persisted to DB.

Get integer value from string in swift

I wrote an extension for that purpose. It always returns an Int. If the string does not fit into an Int, 0 is returned.

extension String {
    func toTypeSafeInt() -> Int {
        if let safeInt = self.toInt() {
            return safeInt
        } else {
            return 0
        }
    }
}

How to host a Node.Js application in shared hosting

You should look for a hosting company that provides such feature, but standard simple static+PHP+MySQL hosting won't let you use node.js.

You need either find a hosting designed for node.js or buy a Virtual Private Server and install it yourself.

Best lightweight web server (only static content) for Windows

I played a bit with Rupy. It's a pretty neat, open source (GPL) Java application and weighs less than 60KB. Give it a try!

How do I access Configuration in any class in ASP.NET Core?

Update

Using ASP.NET Core 2.0 will automatically add the IConfiguration instance of your application in the dependency injection container. This also works in conjunction with ConfigureAppConfiguration on the WebHostBuilder.

For example:

public static void Main(string[] args)
{
    var host = WebHost.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration(builder =>
        {
            builder.AddIniFile("foo.ini");
        })
        .UseStartup<Startup>()
        .Build();

    host.Run();
}

It's just as easy as adding the IConfiguration instance to the service collection as a singleton object in ConfigureServices:

public void ConfigureServices(IServiceCollection services)
{
   services.AddSingleton<IConfiguration>(Configuration);

   // ...
}

Where Configuration is the instance in your Startup class.

This allows you to inject IConfiguration in any controller or service:

public class HomeController
{
   public HomeController(IConfiguration configuration)
   {
      // Use IConfiguration instance
   }
}

How can get the text of a div tag using only javascript (no jQuery)

Actually you dont need to call document.getElementById() function to get access to your div.

You can use this object directly by id:

text = test.textContent || test.innerText;
alert(text);

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

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

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

How do I remove the blue styling of telephone numbers on iPhone/iOS?

If you want to retain the function of the phone-number, but just remove the underline for display purposes, you can style the link as any other:

a:link {text-decoration: none; /* or: underline | line-through | overline | blink (don't use blink. Ever. Please.) */ }

I haven't seen documentation that suggest a class is applied to the phone number links, so you'll have to add classes/ids to links you want to have a different style.

Alternatively you can style the link using:

a[href^=tel] { /* css */ }

Which is understood by iPhone, and won't be applied (so far as I know, perhaps Android, Blackberry, etc. users/devs can comment) by any other UA.

MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?

Firstly you can find duplicate rows and find count of rows is used how many times and order it by number like this;

_x000D_
_x000D_
SELECT q.id,q.name,q.password,q.NID,(select count(*) from UserInfo k where k.NID= q.NID) as Count,_x000D_
(_x000D_
  CASE q.NID_x000D_
  WHEN @curCode THEN_x000D_
   @curRow := @curRow + 1_x000D_
  ELSE_x000D_
   @curRow := 1_x000D_
  AND @curCode := q.NID_x000D_
  END_x000D_
 ) AS No_x000D_
FROM UserInfo q,_x000D_
(_x000D_
  SELECT_x000D_
   @curRow := 1,_x000D_
   @curCode := ''_x000D_
 ) rt_x000D_
WHERE q.NID IN_x000D_
(_x000D_
    SELECT NID_x000D_
    FROM UserInfo_x000D_
    GROUP BY NID_x000D_
    HAVING COUNT(*) > 1_x000D_
) 
_x000D_
_x000D_
_x000D_

after that create a table and insert result to it.

_x000D_
_x000D_
create table CopyTable _x000D_
SELECT q.id,q.name,q.password,q.NID,(select count(*) from UserInfo k where k.NID= q.NID) as Count,_x000D_
(_x000D_
  CASE q.NID_x000D_
  WHEN @curCode THEN_x000D_
   @curRow := @curRow + 1_x000D_
  ELSE_x000D_
   @curRow := 1_x000D_
  AND @curCode := q.NID_x000D_
  END_x000D_
 ) AS No_x000D_
FROM UserInfo q,_x000D_
(_x000D_
  SELECT_x000D_
   @curRow := 1,_x000D_
   @curCode := ''_x000D_
 ) rt_x000D_
WHERE q.NID IN_x000D_
(_x000D_
    SELECT NID_x000D_
    FROM UserInfo_x000D_
    GROUP BY NID_x000D_
    HAVING COUNT(*) > 1_x000D_
) 
_x000D_
_x000D_
_x000D_

Finally, delete dublicate rows.No is start 0. Except fist number of each group delete all dublicate rows.

_x000D_
_x000D_
delete from  CopyTable where No!= 0;
_x000D_
_x000D_
_x000D_

When to use Interface and Model in TypeScript / Angular

Interfaces are only at compile time. This allows only you to check that the expected data received follows a particular structure. For this you can cast your content to this interface:

this.http.get('...')
    .map(res => <Product[]>res.json());

See these questions:

You can do something similar with class but the main differences with class are that they are present at runtime (constructor function) and you can define methods in them with processing. But, in this case, you need to instantiate objects to be able to use them:

this.http.get('...')
    .map(res => {
      var data = res.json();
      return data.map(d => {
        return new Product(d.productNumber,
          d.productName, d.productDescription);
      });
    });

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

In case you don't want to mix up with default change event you can provide your custom event

$('input.test').on('value_changed', function(e){
    console.log('value changed to '+$(this).val());
});

to trigger the event on value set, you can do

$('input.test').val('I am a new value').trigger('value_changed');

Setting the default active profile in Spring-boot

First of all, with the solution below, is necessary to understand that always the spring boot will read the application.properties file. So the other's profile files only will complement and replace the properties defined before.

Considering the follow files:

application.properties
application-qa.properties
application-prod.properties

1) Very important. The application.properties, and just this file, must have the follow line:

[email protected]@

2) Change what you want in the QA and PROD configuration files to see the difference between the environments.

3) By command line, start the spring boot app with any of this options:

It will start the app with the default application.properties file:

mvn spring-boot:run

It will load the default application.properties file and after the application-qa.properties file, replacing and/or complementing the default configuration:

mvn spring-boot:run -Dspring.profiles.active=qa

The same here but with the production environment instead of QA:

mvn spring-boot:run -Dspring.profiles.active=prod

How to revert a "git rm -r ."?

Update:

Since git rm . deletes all files in this and child directories in the working checkout as well as in the index, you need to undo each of these changes:

git reset HEAD . # This undoes the index changes
git checkout .   # This checks out files in this and child directories from the HEAD

This should do what you want. It does not affect parent folders of your checked-out code or index.


Old answer that wasn't:

reset HEAD

will do the trick, and will not erase any uncommitted changes you have made to your files.

after that you need to repeat any git add commands you had queued up.

How do I break a string in YAML over multiple lines?

You might not believe it, but YAML can do multi-line keys too:

?
 >
 multi
 line
 key
:
  value

What does the "~" (tilde/squiggle/twiddle) CSS selector mean?

Note that in an attribute selector (e.g., [attr~=value]), the tilde

Represents an element with an attribute name of attr whose value is a whitespace-separated list of words, one of which is exactly value.

https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors

How to get Printer Info in .NET?

It's been a long time since I've worked in a Windows environment, but I would suggest that you look at using WMI.

Python: avoid new line with print command

If you're using Python 2.5, this won't work, but for people using 2.6 or 2.7, try

from __future__ import print_function

print("abcd", end='')
print("efg")

results in

abcdefg

For those using 3.x, this is already built-in.

Return different type of data from a method in java?

No. Java methods can only return one result (void, a primitive, or an object), and creating a struct-type class like this is exactly how you do it.

As a note, it is frequently possible to make classes like your ReturningValues immutable like this:

public class ReturningValues {
    public final String value;
    public final int index;

    public ReturningValues(String value, int index) {
        this.value = value;
        this.index = index;
    }
}

This has the advantage that a ReturningValues can be passed around, such as between threads, with no concerns about accidentally getting things out of sync.

How do I check if a variable exists?

I created a custom function.

def exists(var):
     return var in globals()

Then the call the function like follows replacing variable_name with the variable you want to check:

exists("variable_name")

Will return True or False

Excel VBA - select multiple columns not in sequential order

Some of the code looks a bit complex to me. This is very simple code to select only the used rows in two discontiguous columns D and H. It presumes the columns are of unequal length and thus more flexible vs if the columns were of equal length.

As you most likely surmised 4=column D and 8=column H

Dim dlastRow As Long
Dim hlastRow As Long

dlastRow = ActiveSheet.Cells(Rows.Count, 4).End(xlUp).Row
hlastRow = ActiveSheet.Cells(Rows.Count, 8).End(xlUp).Row
Range("D2:D" & dlastRow & ",H2:H" & hlastRow).Select

Hope you find useful - DON'T FORGET THAT COMMA BEFORE THE SECOND COLUMN, AS I DID, OR IT WILL BOMB!!

Can I call curl_setopt with CURLOPT_HTTPHEADER multiple times to set multiple headers?

Other type of format :

$headers[] = 'Accept: application/json';
$headers[] = 'Content-Type: application/json';
$headers[] = 'Content-length: 0';

curl_setopt($curlHandle, CURLOPT_HTTPHEADER, $headers);

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

unbound prefix error for ViewPager Indicator:

Along with the following header tags in your parentLayout:

xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"

Also add:

xmlns:app="http://schemas.android.com/apk/res-auto"

This did the trick for me.

Spring RestTemplate timeout

To expand on benscabbia's answer:

private RestTemplate restCaller = new RestTemplate(getClientHttpRequestFactory());

private ClientHttpRequestFactory getClientHttpRequestFactory() {
    int connectionTimeout = 5000; // milliseconds
    int socketTimeout = 10000; // milliseconds
    RequestConfig config = RequestConfig.custom()
      .setConnectTimeout(connectionTimeout)
      .setConnectionRequestTimeout(connectionTimeout)
      .setSocketTimeout(socketTimeout)
      .build();
    CloseableHttpClient client = HttpClientBuilder
      .create()
      .setDefaultRequestConfig(config)
      .build();
    return new HttpComponentsClientHttpRequestFactory(client);
}

Regex match everything after question mark?

str.replace(/^.+?\"|^.|\".+/, '');

This is sometimes bad to use when you wanna select what else to remove between "" and you cannot use it more than twice in one string. All it does is select whatever is not in between "" and replace it with nothing.

Even for me it is a bit confusing, but ill try to explain it. ^.+? (not anything OPTIONAL) till first " then | Or/stop (still researching what it really means) till/at ^. has selected nothing until before the 2nd " using (| stop/at). And select all that comes after with .+.

What is mapDispatchToProps?

mapStateToProps() is a utility which helps your component get updated state(which is updated by some other components),
mapDispatchToProps() is a utility which will help your component to fire an action event (dispatching action which may cause change of application state)

Swift's guard keyword

Guard statement going to do . it is couple of different

1) it is allow me to reduce nested if statement
2) it is increase my scope which my variable accessible

if Statement

func doTatal(num1 : Int?, num2: Int?) {
  // nested if statement
    if let fistNum = num1 where num1 > 0 {
        if let lastNum = num2 where num2 < 50 {

          let total = fistNum + lastNum
        }
    }
 // don't allow me to access out of the scope 
 //total = fistNum + lastNum 
}

Guard statement

func doTatal(num1 : Int?, num2: Int?) {
   //reduce  nested if statement and check positive way not negative way 
    guard let fistNum = num1 where num1 > 0 else{
      return
    }
    guard  let lastNum = num2 where num2 < 50 else {
     return
    }
    // increase my scope which my variable accessible
    let total = fistNum + lastNum

}

Update UI from Thread in Android

If you don't like the AsyncTask you could use the observer pattern. In that example use the ResponseHandler as an inner class in your activity then have a string message that will set the progress bars percentage... You would need to make sure that any alterations to the UI are performed within the ResponseHandler to avoid freezing up the UI, then your worker thread (EventSource in the example) can perform the tasks required.

I would use the AsyncTask tho, however the observer pattern can be good for customization reasons, plus its easier to understand. Also im not sure if this way is widely accepted or will 100% work. Im downloading and the android plugin now to test it

`IF` statement with 3 possible answers each based on 3 different ranges

This is what I did:

Very simply put:

=IF(C7>100,"Profit",IF(C7=100,"Quota Met","Loss"))

The first IF Statement, if true will input Profit, and if false will lead on to the next IF statement and so forth :)

I only have basic formula knowledge but it's working so I will accept I am right!

Xcode Objective-C | iOS: delay function / NSTimer help?

Try

NSDate *future = [NSDate dateWithTimeIntervalSinceNow: 0.06 ];
[NSThread sleepUntilDate:future];

How to Replace Multiple Characters in SQL?

Here are the steps

  1. Create a CLR function

See following code:

public partial class UserDefinedFunctions 
{

[Microsoft.SqlServer.Server.SqlFunction]
public static SqlString Replace2(SqlString inputtext, SqlString filter,SqlString      replacewith)
{

    string str = inputtext.ToString();
    try
    {
        string pattern = (string)filter;
        string replacement = (string)replacewith;
        Regex rgx = new Regex(pattern);
        string result = rgx.Replace(str, replacement);
        return (SqlString)result;

    }
    catch (Exception s)
    {
        return (SqlString)s.Message;
    }
}
}
  1. Deploy your CLR function

  2. Now Test it

See following code:

create table dbo.test(dummydata varchar(255))
Go
INSERT INTO dbo.test values('P@ssw1rd'),('This 12is @test')
Go
Update dbo.test
set dummydata=dbo.Replace2(dummydata,'[0-9@]','')

select * from dbo.test
dummydata, Psswrd, This is test booom!!!!!!!!!!!!!

How to create/read/write JSON files in Qt5

An example on how to use that would be great. There is a couple of examples at the Qt forum, but you're right that the official documentation should be expanded.

QJsonDocument on its own indeed doesn't produce anything, you will have to add the data to it. That's done through the QJsonObject, QJsonArray and QJsonValue classes. The top-level item needs to be either an array or an object (because 1 is not a valid json document, while {foo: 1} is.)

Calculate logarithm in python

If you use log without base it uses e.

From the comment

Return the logarithm of x to the given base.
If the base not specified, returns the natural logarithm (base e) of x.

Therefor you have to use:

import math
print( math.log(1.5, 10))

Execute a shell function with timeout

This function uses only builtins

  • Maybe consider evaling "$*" instead of running $@ directly depending on your needs

  • It starts a job with the command string specified after the first arg that is the timeout value and monitors the job pid

  • It checks every 1 seconds, bash supports timeouts down to 0.01 so that can be tweaked

  • Also if your script needs stdin, read should rely on a dedicated fd (exec {tofd}<> <(:))

  • Also you might want to tweak the kill signal (the one inside the loop) which is default to -15, you might want -9

## forking is evil
timeout() {
    to=$1; shift
    $@ & local wp=$! start=0
     while kill -0 $wp; do
        read -t 1
        start=$((start+1))
        if [ $start -ge $to ]; then
            kill $wp && break
        fi
    done
}

How do I access call log for android?

use this method from everywhere with a context

private static String getCallDetails(Context context) {
    StringBuffer stringBuffer = new StringBuffer();
    Cursor cursor = context.getContentResolver().query(CallLog.Calls.CONTENT_URI,
            null, null, null, CallLog.Calls.DATE + " DESC");
    int number = cursor.getColumnIndex(CallLog.Calls.NUMBER);
    int type = cursor.getColumnIndex(CallLog.Calls.TYPE);
    int date = cursor.getColumnIndex(CallLog.Calls.DATE);
    int duration = cursor.getColumnIndex(CallLog.Calls.DURATION);       
    while (cursor.moveToNext()) {
        String phNumber = cursor.getString(number);
        String callType = cursor.getString(type);
        String callDate = cursor.getString(date);
        Date callDayTime = new Date(Long.valueOf(callDate));
        String callDuration = cursor.getString(duration);
        String dir = null;
        int dircode = Integer.parseInt(callType);
        switch (dircode) {
        case CallLog.Calls.OUTGOING_TYPE:
            dir = "OUTGOING";
            break;
        case CallLog.Calls.INCOMING_TYPE:
            dir = "INCOMING";
            break;

        case CallLog.Calls.MISSED_TYPE:
            dir = "MISSED";
            break;
        }
        stringBuffer.append("\nPhone Number:--- " + phNumber + " \nCall Type:--- "
                + dir + " \nCall Date:--- " + callDayTime
                + " \nCall duration in sec :--- " + callDuration);
        stringBuffer.append("\n----------------------------------");
    }
    cursor.close();
    return stringBuffer.toString();
}

How do I find the location of Python module sources?

Not all python modules are written in python. Datetime happens to be one of them that is not, and (on linux) is datetime.so.

You would have to download the source code to the python standard library to get at it.

Split string using a newline delimiter with Python

If you want to split only by newlines, you can use str.splitlines():

Example:

>>> data = """a,b,c
... d,e,f
... g,h,i
... j,k,l"""
>>> data
'a,b,c\nd,e,f\ng,h,i\nj,k,l'
>>> data.splitlines()
['a,b,c', 'd,e,f', 'g,h,i', 'j,k,l']

With str.split() your case also works:

>>> data = """a,b,c
... d,e,f
... g,h,i
... j,k,l"""
>>> data
'a,b,c\nd,e,f\ng,h,i\nj,k,l'
>>> data.split()
['a,b,c', 'd,e,f', 'g,h,i', 'j,k,l']

However if you have spaces (or tabs) it will fail:

>>> data = """
... a, eqw, qwe
... v, ewr, err
... """
>>> data
'\na, eqw, qwe\nv, ewr, err\n'
>>> data.split()
['a,', 'eqw,', 'qwe', 'v,', 'ewr,', 'err']

Changing PowerShell's default output encoding to UTF-8

To be short, use:

write-output "your text" | out-file -append -encoding utf8 "filename"

Java math function to convert positive int to negative and negative to positive?

We can reverse Java number int or double using this :

int x = 5;
int y = -7;

x = x - (x*2); // reverse to negative
y = y - (y*2); // reverse to positif

Simple algorithm to reverse number :)

How do I pass environment variables to Docker containers?

The problem I had was that I was putting the --env-file at the end of the command

docker run -it --rm -p 8080:80 imagename --env-file ./env.list

Fix

docker run --env-file ./env.list -it --rm -p 8080:80 imagename

Select n random rows from SQL Server table

Try this:

SELECT TOP 10 Field1, ..., FieldN
FROM Table1
ORDER BY NEWID()

Using (Ana)conda within PyCharm

Change the project interpreter to ~/anaconda2/python/bin by going to File -> Settings -> Project -> Project Interpreter. Also update the run configuration to use the project default Python interpreter via Run -> Edit Configurations. This makes PyCharm use Anaconda instead of the default Python interpreter under usr/bin/python27.

Insert data to MySql DB and display if insertion is success or failure

According to the book PHP and MySQL for Dynamic Web Sites (4th edition)

Example:

$r = mysqli_query($dbc, $q);

For simple queries like INSERT, UPDATE, DELETE, etc. (which do not return records), the $r variable—short for result—will be either TRUE or FALSE, depending upon whether the query executed successfully.

Keep in mind that “executed successfully” means that it ran without error; it doesn’t mean that the query’s execution necessarily had the desired result; you’ll need to test for that.

Then how to test?

While the mysqli_num_rows() function will return the number of rows generated by a SELECT query, mysqli_affected_rows() returns the number of rows affected by an INSERT, UPDATE, or DELETE query. It’s used like so:

$num = mysqli_affected_rows($dbc);

Unlike mysqli_num_rows(), the one argument the function takes is the database connection ($dbc), not the results of the previous query ($r).

Key Presses in Python

Check This module keyboard with many features.Install it, perhaps with this command:

pip3 install keyboard

Then Use this Code:

import keyboard
keyboard.write('A',delay=0)

If you Want to write 'A' multiple times, Then simply use a loop.
Note:
The key 'A' will be pressed for the whole windows.Means the script is running and you went to browser, the script will start writing there.

Install IPA with iTunes 11

In iTunes 11 you can go to the view menu, and "Show Sidebar", this will give you the sidebar, that you can drag 'n drop to.

You'll drag 'n drop to the open area that will be near the bottom of the sidebar (I'm typically doing this with both an IPA and a provisioning profile). After you do that, there will be an apps menu that appears in the sidebar with your app in it. Click on that, and you'll see your application in the main view. You can then drag your application from there to your device. Below, please find a video (it's private, so you'll need the URL) that outlines the steps visually: http://youtube.com/watch?v=0ACq4CRpEJ8&feature=youtu.be

Java Synchronized list

It will give consistent behavior for add/remove operations. But while iterating you have to explicitly synchronized. Refer this link

How to put an image next to each other

Change div to span. And space the icons using &nbsp; HTML

 <div class="nav3" style="height:705px;">
 <span class="icons"><a href="http://www.facebook.com/"><img src="images/facebook.png"></a>
 </span>&nbsp;&nbsp;&nbsp;
 <span class="icons"><a href="https://twitter.com"><img src="images/twitter.png"></a>
 </span>
 </div>

CSS

.nav3 {
background-color: #E9E8C7;
height: auto;
width: 150px;
float: left;
padding-left: 20px;
font-family: Arial, Helvetica, sans-serif;
font-size: 12px;
color: #333333;
padding-top: 20px;
padding-right: 20px;
}

.icons{
display:inline-block;
width: 64px; 
height: 64px; 
}

 a.icons:hover {
 background: #C93;
 }

span does not break line, div does.

How to access Spring context in jUnit tests annotated with @RunWith and @ContextConfiguration?

If your test class extends the Spring JUnit classes
(e.g., AbstractTransactionalJUnit4SpringContextTests or any other class that extends AbstractSpringContextTests), you can access the app context by calling the getContext() method.
Check out the javadocs for the package org.springframework.test.

How do I turn off the mysql password validation?

Further to the answer from ktbos:

I modified the mysqld.cnf file and mysql failed to start. It turned out that I was modifying the wrong file!

So be sure the file you modify contains segment tags like [mysqld_safe] and [mysqld]. Under the latter I did as suggested and added the line:

validate_password_policy=LOW

This worked perfectly to resolve my issue of not requiring special characters within the password.

Is there any difference between "!=" and "<>" in Oracle Sql?

At university we were taught 'best practice' was to use != when working for employers, though all the operators above have the same functionality.

How can I retrieve Id of inserted entity using Entity framework?

The object you're saving should have a correct Id after propagating changes into database.

What is the best way to use a HashMap in C++?

The standard library includes the ordered and the unordered map (std::map and std::unordered_map) containers. In an ordered map the elements are sorted by the key, insert and access is in O(log n). Usually the standard library internally uses red black trees for ordered maps. But this is just an implementation detail. In an unordered map insert and access is in O(1). It is just another name for a hashtable.

An example with (ordered) std::map:

#include <map>
#include <iostream>
#include <cassert>

int main(int argc, char **argv)
{
  std::map<std::string, int> m;
  m["hello"] = 23;
  // check if key is present
  if (m.find("world") != m.end())
    std::cout << "map contains key world!\n";
  // retrieve
  std::cout << m["hello"] << '\n';
  std::map<std::string, int>::iterator i = m.find("hello");
  assert(i != m.end());
  std::cout << "Key: " << i->first << " Value: " << i->second << '\n';
  return 0;
}

Output:

23
Key: hello Value: 23

If you need ordering in your container and are fine with the O(log n) runtime then just use std::map.

Otherwise, if you really need a hash-table (O(1) insert/access), check out std::unordered_map, which has a similar to std::map API (e.g. in the above example you just have to search and replace map with unordered_map).

The unordered_map container was introduced with the C++11 standard revision. Thus, depending on your compiler, you have to enable C++11 features (e.g. when using GCC 4.8 you have to add -std=c++11 to the CXXFLAGS).

Even before the C++11 release GCC supported unordered_map - in the namespace std::tr1. Thus, for old GCC compilers you can try to use it like this:

#include <tr1/unordered_map>

std::tr1::unordered_map<std::string, int> m;

It is also part of boost, i.e. you can use the corresponding boost-header for better portability.

How to show uncommitted changes in Git and some Git diffs in detail

I had a situation of git status showing changes, but git diff printing nothing, although there were changes in several lines. However:

$ git diff data.txt > myfile
$ cat myfile
<prints diff>

Git 2.20.1 on raspbian. Other commands like git checkout, git pull are printing to stdout without problems.

Remove specific rows from a data frame

 X <- data.frame(Variable1=c(11,14,12,15),Variable2=c(2,3,1,4))
> X
  Variable1 Variable2
1        11         2
2        14         3
3        12         1
4        15         4
> X[X$Variable1!=11 & X$Variable1!=12, ]
  Variable1 Variable2
2        14         3
4        15         4
> X[ ! X$Variable1 %in% c(11,12), ]
  Variable1 Variable2
2        14         3
4        15         4

You can functionalize this however you like.

Best Practice for Forcing Garbage Collection in C#

Not sure if it is a best practice, but when working with large amounts of images in a loop (i.e. creating and disposing a lot of Graphics/Image/Bitmap objects), i regularly let the GC.Collect.

I think I read somewhere that the GC only runs when the program is (mostly) idle, and not in the middle of a intensive loop, so that could look like an area where manual GC could make sense.

PHP error: "The zip extension and unzip command are both missing, skipping."

For Debian Jessie (which is the current default for the PHP image on Docker Hub):

apt-get install --yes zip unzip php-pclzip

You can omit the --yes, but it's useful when you're RUN-ing it in a Dockerfile.

Open fancybox from function

Here is working code as per the author's Tips & Tricks blog post, put it in document ready:

  $("#mybutton").click(function(){
    $(".fancybox").trigger('click');  
  })

This triggers the smaller version of the currently displayed image or content, as if you had clicked on it manually. It avoids initializing the Fancybox again, but instead keeps the parameters you initialized it with on document ready. If you need to do something different when opening the box with a separate button compared to clicking on the box, you will need the parameters, but for many, this will be what they were looking for.

"installation of package 'FILE_PATH' had non-zero exit status" in R

The .zip file provided by the authors is not a valid R package, and they do state that the source is for "direct use" in R (by which I assume they mean it's necessary to load the included functions manually). The non-zero exit status simply indicates that there was an error during the installation of the "package".

You can extract the archive manually and then load the functions therein with, e.g., source('bivpois.table.R'), or you can download the .RData file they provide and load that into the workspace with load('.RData'). This does not install the functions as part of a package; rather, it loads the functions into your global environment, making them temporarily available.

You can download, extract, and load the .RData from R as follows:

download.file('http://stat-athens.aueb.gr/~jbn/papers/files/14/14_bivpois_RDATA.zip', 
              f <- tempfile())
unzip(f, exdir=tempdir())
load(file.path(tempdir(), '.RData'))

If you want the .RData file to be available in the current working directory, to be loaded in the future, you could use the following instead:

download.file('http://stat-athens.aueb.gr/~jbn/papers/files/14/14_bivpois_RDATA.zip', 
              f <- tempfile())
unzip(f, exdir=tempdir())
file.copy(file.path(tempdir(), '.RData'), 'bivpois.RData')
# the above copies the .RData file to a file called bivpois.RData in your current 
# working directory.
load('bivpois.RData')

In future R sessions, you can just call load('bivpois.RData').

Using the rJava package on Win7 64 bit with R

Sorry for necro. I have too run into the same issue and found out that rJava expects JAVA_HOME to point to JRE. If you have JDK installed, most probably your JAVA_HOME points to JDK. My quick solution:

Sys.setenv(JAVA_HOME=paste(Sys.getenv("JAVA_HOME"), "jre", sep="\\"))

python JSON object must be str, bytes or bytearray, not 'dict

json.dumps() is used to decode JSON data

import json

# initialize different data
str_data = 'normal string'
int_data = 1
float_data = 1.50
list_data = [str_data, int_data, float_data]
nested_list = [int_data, float_data, list_data]
dictionary = {
    'int': int_data,
    'str': str_data,
    'float': float_data,
    'list': list_data,
    'nested list': nested_list
}

# convert them to JSON data and then print it
print('String :', json.dumps(str_data))
print('Integer :', json.dumps(int_data))
print('Float :', json.dumps(float_data))
print('List :', json.dumps(list_data))
print('Nested List :', json.dumps(nested_list, indent=4))
print('Dictionary :', json.dumps(dictionary, indent=4))  # the json data will be indented

output:

String : "normal string"
Integer : 1
Float : 1.5
List : ["normal string", 1, 1.5]
Nested List : [
    1,
    1.5,
    [
        "normal string",
        1,
        1.5
    ]
]
Dictionary : {
    "int": 1,
    "str": "normal string",
    "float": 1.5,
    "list": [
        "normal string",
        1,
        1.5
    ],
    "nested list": [
        1,
        1.5,
        [
            "normal string",
            1,
            1.5
        ]
    ]
}
  • Python Object to JSON Data Conversion
|                 Python                 |  JSON  |
|:--------------------------------------:|:------:|
|                  dict                  | object |
|               list, tuple              |  array |
|                   str                  | string |
| int, float, int- & float-derived Enums | number |
|                  True                  |  true  |
|                  False                 |  false |
|                  None                  |  null  |

json.loads() is used to convert JSON data into Python data.

import json

# initialize different JSON data
arrayJson = '[1, 1.5, ["normal string", 1, 1.5]]'
objectJson = '{"a":1, "b":1.5 , "c":["normal string", 1, 1.5]}'

# convert them to Python Data
list_data = json.loads(arrayJson)
dictionary = json.loads(objectJson)

print('arrayJson to list_data :\n', list_data)
print('\nAccessing the list data :')
print('list_data[2:] =', list_data[2:])
print('list_data[:1] =', list_data[:1])

print('\nobjectJson to dictionary :\n', dictionary)
print('\nAccessing the dictionary :')
print('dictionary[\'a\'] =', dictionary['a'])
print('dictionary[\'c\'] =', dictionary['c'])

output:

arrayJson to list_data :
 [1, 1.5, ['normal string', 1, 1.5]]

Accessing the list data :
list_data[2:] = [['normal string', 1, 1.5]]
list_data[:1] = [1]

objectJson to dictionary :
 {'a': 1, 'b': 1.5, 'c': ['normal string', 1, 1.5]}

Accessing the dictionary :
dictionary['a'] = 1
dictionary['c'] = ['normal string', 1, 1.5]
  • JSON Data to Python Object Conversion
|      JSON     | Python |
|:-------------:|:------:|
|     object    |  dict  |
|     array     |  list  |
|     string    |   str  |
|  number (int) |   int  |
| number (real) |  float |
|      true     |  True  |
|     false     |  False |

APT command line interface-like yes/no input?

How about this:

def yes(prompt = 'Please enter Yes/No: '):
while True:
    try:
        i = raw_input(prompt)
    except KeyboardInterrupt:
        return False
    if i.lower() in ('yes','y'): return True
    elif i.lower() in ('no','n'): return False

How to reset radiobuttons in jQuery so that none is checked

Radio button set checked through jquery:

<div id="somediv" >
 <input type="radio" name="enddate" value="1"  />
 <input type="radio" name="enddate" value="2"  />
 <input type="radio" name="enddate" value="3"  />
</div>

jquery code:

$('div#somediv input:radio:nth(0)').attr("checked","checked");

Download pdf file using jquery ajax

You can do this with html5 very easily:

var link = document.createElement('a');
link.href = "/WWW/test.pdf";
link.download = "file_" + new Date() + ".pdf";
link.click();
link.remove()

Git status ignore line endings / identical files / windows & linux environment / dropbox / mled

Try setting core.autocrlf value like this :

git config --global core.autocrlf true

What is the correct way to check for string equality in JavaScript?

what led me to this question is the padding and white-spaces

check my case

 if (title === "LastName")
      doSomething();

and title was " LastName"

enter image description here

so maybe you have to use trim function like this

var title = $(this).text().trim();

How do you overcome the HTML form nesting limitation?

This discussion is still of interest to me. Behind the original post are "requirements" which the OP seems to share - i.e. a form with backward compatibility. As someone whose work at the time of writing must sometimes support back to IE6 (and for years to come), I dig that.

Without pushing the framework (all organizations are going to want to reassure themselves on compatibility/robustness, and I'm not using this discussion as justification for the framework), the Drupal solutions to this issue are interesting. Drupal is also directly relevant because the framework has had a long time policy of "it should work without Javascript (only if you want)" i.e. the OP's issue.

Drupal uses it's rather extensive form.inc functions to find the triggering_element (yes, that's the name in code). See the bottom of the code listed on the API page for form_builder (if you'd like to dig into details, the source is recommended - drupal-x.xx/includes/form.inc). The builder uses automatic HTML attribute generation and, via that, can on return detect which button was pressed, and act accordingly (these can be set up to run separate processes too).

Beyond the form builder, Drupal splits data 'delete' actions into separate URLs/forms, likely for the reasons mentioned in the original post. This needs some sort of search/listing step (groan another form! but is user-friendly) as a preliminary. But this has the advantage of eliminating the "submit everything" issue. The big form with the data is used for it's intended purpose, data creation/updating (or even a 'merge' action).

In other words, one way of working around the problem is to devolve the form into two, then the problem vanishes (and the HTML methods can be corrected through a POST too).

How to create json by JavaScript for loop?

From what I understand of your request, this should work:

<script>
//  var status  = document.getElementsByID("uniqueID"); // this works too
var status  = document.getElementsByName("status")[0];
var jsonArr = [];

for (var i = 0; i < status.options.length; i++) {
    jsonArr.push({
        id: status.options[i].text,
        optionValue: status.options[i].value
    });
}
</script>

Custom method names in ASP.NET Web API

Just modify your WebAPIConfig.cs as bellow

Routes.MapHttpRoute(
  name: "DefaultApi",
  routeTemplate: "api/{controller}/{action}/{id}",
  defaults: new { action = "get", id = RouteParameter.Optional });

Then implement your API as bellow

    // GET: api/Controller_Name/Show/1
    [ActionName("Show")]
    [HttpGet]
    public EventPlanner Id(int id){}

How exactly do you configure httpOnlyCookies in ASP.NET?

With props to Rick (second comment down in the blog post mentioned), here's the MSDN article on httpOnlyCookies.

Bottom line is that you just add the following section in your system.web section in your web.config:

<httpCookies domain="" httpOnlyCookies="true|false" requireSSL="true|false" />

What's the difference between .bashrc, .bash_profile, and .environment?

Classically, ~/.profile is used by Bourne Shell, and is probably supported by Bash as a legacy measure. Again, ~/.login and ~/.cshrc were used by C Shell - I'm not sure that Bash uses them at all.

The ~/.bash_profile would be used once, at login. The ~/.bashrc script is read every time a shell is started. This is analogous to /.cshrc for C Shell.

One consequence is that stuff in ~/.bashrc should be as lightweight (minimal) as possible to reduce the overhead when starting a non-login shell.

I believe the ~/.environment file is a compatibility file for Korn Shell.

Read pdf files with php

your initial request is "I have a large PDF file that is a floor map for a building. "

I am afraid to tell you this might be harder than you guess.

Cause the last known lib everyones use to parse pdf is smalot, and this one is known to encounter issue regarding large file.

Here too, Lookig for a real php lib to parse pdf, without any memory peak that need a php configuration to disable memory limit as lot of "developers" does (which I guess is really not advisable).

see this post for more details about smalot performance : https://github.com/smalot/pdfparser/issues/163

Where do alpha testers download Google Play Android apps?

You can use a Google Group and have your alpha testers just join the group. Everything else should just be handled through the Google Play Store App.

How to concat string + i?

You can concatenate strings using strcat. If you plan on concatenating numbers as strings, you must first use num2str to convert the numbers to strings.

Also, strings can't be stored in a vector or matrix, so f must be defined as a cell array, and must be indexed using { and } (instead of normal round brackets).

f = cell(N, 1);
for i=1:N
   f{i} = strcat('f', num2str(i));
end

Easy login script without database

FacebookConnect or OpenID are two great options.

Basically, your users login to other sites they are already members of (Facebook, or Google), and then you get confirmation from that site telling you the user is trustworthy - start a session, and they're logged in. No database needed (unless you want to associate more data to their account).

How to show only next line after the matched one?

If you want to stick to grep:

grep -A1 'blah' logfile | grep -v "blah"

or alternatively with sed:

sed -n '/blah/{n;p;}' logfile

Ant: How to execute a command for each file in directory?

ant-contrib is evil; write a custom ant task.

ant-contrib is evil because it tries to convert ant from a declarative style to an imperative style. But xml makes a crap programming language.

By contrast a custom ant task allows you to write in a real language (Java), with a real IDE, where you can write unit tests to make sure you have the behavior you want, and then make a clean declaration in your build script about the behavior you want.

This rant only matters if you care about writing maintainable ant scripts. If you don't care about maintainability by all means do whatever works. :)

Jtf

How do I read a specified line in a text file?

You could read line by line so you don't have to read the entire all at once (probably at all)

int i=0
while(!stream.eof() && i!=lineNum)
    stream.readLine()
    i++
line = stream.readLine()

Pandas every nth row

There is an even simpler solution to the accepted answer that involves directly invoking df.__getitem__.

df = pd.DataFrame('x', index=range(5), columns=list('abc'))
df

   a  b  c
0  x  x  x
1  x  x  x
2  x  x  x
3  x  x  x
4  x  x  x

For example, to get every 2 rows, you can do

df[::2]

   a  b  c
0  x  x  x
2  x  x  x
4  x  x  x

There's also GroupBy.first/GroupBy.head, you group on the index:

df.index // 2
# Int64Index([0, 0, 1, 1, 2], dtype='int64')

df.groupby(df.index // 2).first()
# Alternatively,
# df.groupby(df.index // 2).head(1)

   a  b  c
0  x  x  x
1  x  x  x
2  x  x  x

The index is floor-divved by the stride (2, in this case). If the index is non-numeric, instead do

# df.groupby(np.arange(len(df)) // 2).first()
df.groupby(pd.RangeIndex(len(df)) // 2).first()

   a  b  c
0  x  x  x
1  x  x  x
2  x  x  x

Custom HTTP headers : naming conventions

The question bears re-reading. The actual question asked is not similar to vendor prefixes in CSS properties, where future-proofing and thinking about vendor support and official standards is appropriate. The actual question asked is more akin to choosing URL query parameter names. Nobody should care what they are. But name-spacing the custom ones is a perfectly valid -- and common, and correct -- thing to do.

Rationale:
It is about conventions among developers for custom, application-specific headers -- "data relevant to their account" -- which have nothing to do with vendors, standards bodies, or protocols to be implemented by third parties, except that the developer in question simply needs to avoid header names that may have other intended use by servers, proxies or clients. For this reason, the "X-Gzip/Gzip" and "X-Forwarded-For/Forwarded-For" examples given are moot. The question posed is about conventions in the context of a private API, akin to URL query parameter naming conventions. It's a matter of preference and name-spacing; concerns about "X-ClientDataFoo" being supported by any proxy or vendor without the "X" are clearly misplaced.

There's nothing special or magical about the "X-" prefix, but it helps to make it clear that it is a custom header. In fact, RFC-6648 et al help bolster the case for use of an "X-" prefix, because -- as vendors of HTTP clients and servers abandon the prefix -- your app-specific, private-API, personal-data-passing-mechanism is becoming even better-insulated against name-space collisions with the small number of official reserved header names. That said, my personal preference and recommendation is to go a step further and do e.g. "X-ACME-ClientDataFoo" (if your widget company is "ACME").

IMHO the IETF spec is insufficiently specific to answer the OP's question, because it fails to distinguish between completely different use cases: (A) vendors introducing new globally-applicable features like "Forwarded-For" on the one hand, vs. (B) app developers passing app-specific strings to/from client and server. The spec only concerns itself with the former, (A). The question here is whether there are conventions for (B). There are. They involve grouping the parameters together alphabetically, and separating them from the many standards-relevant headers of type (A). Using the "X-" or "X-ACME-" prefix is convenient and legitimate for (B), and does not conflict with (A). The more vendors stop using "X-" for (A), the more cleanly-distinct the (B) ones will become.

Example:
Google (who carry a bit of weight in the various standards bodies) are -- as of today, 20141102 in this slight edit to my answer -- currently using "X-Mod-Pagespeed" to indicate the version of their Apache module involved in transforming a given response. Is anyone really suggesting that Google should use "Mod-Pagespeed", without the "X-", and/or ask the IETF to bless its use?

Summary:
If you're using custom HTTP Headers (as a sometimes-appropriate alternative to cookies) within your app to pass data to/from your server, and these headers are, explicitly, NOT intended ever to be used outside the context of your application, name-spacing them with an "X-" or "X-FOO-" prefix is a reasonable, and common, convention.

Django DoesNotExist

I have found the solution to this issue using ObjectDoesNotExist on this way

from django.core.exceptions import ObjectDoesNotExist
......

try:
  # try something
except ObjectDoesNotExist:
  # do something

After this, my code works as I need

Thanks any way, your post help me to solve my issue

Initialize array of strings

Its fine to just do char **strings;, char **strings = NULL, or char **strings = {NULL}

but to initialize it you'd have to use malloc:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main(){
    // allocate space for 5 pointers to strings
    char **strings = (char**)malloc(5*sizeof(char*));
    int i = 0;
    //allocate space for each string
    // here allocate 50 bytes, which is more than enough for the strings
    for(i = 0; i < 5; i++){
        printf("%d\n", i);
        strings[i] = (char*)malloc(50*sizeof(char));
    }
    //assign them all something
    sprintf(strings[0], "bird goes tweet");
    sprintf(strings[1], "mouse goes squeak");
    sprintf(strings[2], "cow goes moo");
    sprintf(strings[3], "frog goes croak");
    sprintf(strings[4], "what does the fox say?");
    // Print it out
    for(i = 0; i < 5; i++){
        printf("Line #%d(length: %lu): %s\n", i, strlen(strings[i]),strings[i]);
    } 
    //Free each string
    for(i = 0; i < 5; i++){
        free(strings[i]);
    }
    //finally release the first string
    free(strings);
    return 0;
}

SQL Server: SELECT only the rows with MAX(DATE)

SELECT t1.OrderNo, t1.PartCode, t1.Quantity
FROM table AS t1
INNER JOIN (SELECT OrderNo, MAX(DateEntered) AS MaxDate
            FROM table
            GROUP BY OrderNo) AS t2
ON (t1.OrderNo = t2.OrderNo AND t1.DateEntered = t2.MaxDate)

The inner query selects all OrderNo with their maximum date. To get the other columns of the table, you can join them on OrderNo and the MaxDate.

HTML image not showing in Gmail

For me, the problem was using svg images. I switched them to png and it worked.

get list of packages installed in Anaconda

To list all of the packages in the active environment, use:

conda list

To list all of the packages in a deactivated environment, use:

conda list -n myenv

HTML Upload MAX_FILE_SIZE does not appear to work

There IS A POINT in introducing MAX_FILE_SIZE client side hidden form field.

php.ini can limit uploaded file size. So, while your script honors the limit imposed by php.ini, different HTML forms can further limit an uploaded file size. So, when uploading video, form may limit* maximum size to 10MB, and while uploading photos, forms may put a limit of just 1mb. And at the same time, the maximum limit can be set in php.ini to suppose 10mb to allow all this.

Although this is not a fool proof way of telling the server what to do, yet it can be helpful.

  • HTML does'nt limit anything. It just forwards the server all form variable including MAX_FILE_SIZE and its value.

Hope it helped someone.

How to remove word wrap from textarea?

The following CSS based solution works for me:

<html>
 <head>
  <style type='text/css'>
   textarea {
    white-space: nowrap;
    overflow:    scroll;
    overflow-y:  hidden;
    overflow-x:  scroll;
    overflow:    -moz-scrollbars-horizontal;
   }
  </style>
 </head>
 <body>
  <form>
   <textarea>This is a long line of text for testing purposes...</textarea>
  </form>
 </body>
</html>

Is there a better alternative than this to 'switch on type'?

As per C# 7.0 specification, you can declare a local variable scoped in a case of a switch:

object a = "Hello world";
switch (a)
{
    case string myString:
        // The variable 'a' is a string!
        break;
    case int myInt:
        // The variable 'a' is an int!
        break;
    case Foo myFoo:
        // The variable 'a' is of type Foo!
        break;
}

This is the best way to do such a thing because it involves just casting and push-on-the-stack operations, which are the fastest operations an interpreter can run just after bitwise operations and boolean conditions.

Comparing this to a Dictionary<K, V>, here's much less memory usage: holding a dictionary requires more space in the RAM and some computation more by the CPU for creating two arrays (one for keys and the other for values) and gathering hash codes for the keys to put values to their respective keys.

So, for as far I know, I don't believe that a faster way could exist unless you want to use just an if-then-else block with the is operator as follows:

object a = "Hello world";
if (a is string)
{
    // The variable 'a' is a string!
} else if (a is int)
{
    // The variable 'a' is an int!
} // etc.

How can I compare two strings in java and define which of them is smaller than the other alphabetically?

If you would like to ignore case you could use the following:

String s = "yip";
String best = "yodel";
int compare = s.compareToIgnoreCase(best);
if(compare < 0){
    //-1, --> s is less than best. ( s comes alphabetically first)
}
else if(compare > 0 ){
// best comes alphabetically first.
}
else{
    // strings are equal.
}

Oracle 11g Express Edition for Windows 64bit?

Oracle 11G Express Edition is now available to install on 64-bit versions of Windows.

Oracle 11G Download Page

How to create a CPU spike with a bash command

I combined some of the answers and added a way to scale the stress to all available cpus:

#!/bin/bash

function infinite_loop { 
    while [ 1 ] ; do
        # Force some computation even if it is useless to actually work the CPU
        echo $((13**99)) 1>/dev/null 2>&1
    done
}

# Either use environment variables for DURATION, or define them here
NUM_CPU=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || sysctl -n hw.ncpu)
PIDS=()
for i in `seq ${NUM_CPU}` ;
do
# Put an infinite loop on each CPU
    infinite_loop &
    PIDS+=("$!")
done

# Wait DURATION seconds then stop the loops and quit
sleep ${DURATION}

# Parent kills its children 
for pid in "${PIDS[@]}"
do
    kill $pid
done

How does Trello access the user's clipboard?

Disclosure: I wrote the code that Trello uses; the code below is the actual source code Trello uses to accomplish the clipboard trick.


We don't actually "access the user's clipboard", instead we help the user out a bit by selecting something useful when they press Ctrl+C.

Sounds like you've figured it out; we take advantage of the fact that when you want to hit Ctrl+C, you have to hit the Ctrl key first. When the Ctrl key is pressed, we pop in a textarea that contains the text we want to end up on the clipboard, and select all the text in it, so the selection is all set when the C key is hit. (Then we hide the textarea when the Ctrl key comes up.)

Specifically, Trello does this:

TrelloClipboard = new class
  constructor: ->
    @value = ""

    $(document).keydown (e) =>
      # Only do this if there's something to be put on the clipboard, and it
      # looks like they're starting a copy shortcut
      if !@value || !(e.ctrlKey || e.metaKey)
        return

      if $(e.target).is("input:visible,textarea:visible")
        return

      # Abort if it looks like they've selected some text (maybe they're trying
      # to copy out a bit of the description or something)
      if window.getSelection?()?.toString()
        return

      if document.selection?.createRange().text
        return

      _.defer =>
        $clipboardContainer = $("#clipboard-container")
        $clipboardContainer.empty().show()
        $("<textarea id='clipboard'></textarea>")
        .val(@value)
        .appendTo($clipboardContainer)
        .focus()
        .select()

    $(document).keyup (e) ->
      if $(e.target).is("#clipboard")
        $("#clipboard-container").empty().hide()

  set: (@value) ->

In the DOM we've got:

<div id="clipboard-container"><textarea id="clipboard"></textarea></div>

CSS for the clipboard stuff:

#clipboard-container {
  position: fixed;
  left: 0px;
  top: 0px;
  width: 0px;
  height: 0px;
  z-index: 100;
  display: none;
  opacity: 0;
}
#clipboard {
  width: 1px;
  height: 1px;
  padding: 0px;
}

... and the CSS makes it so you can't actually see the textarea when it pops in ... but it's "visible" enough to copy from.

When you hover over a card, it calls

TrelloClipboard.set(cardUrl)

... so then the clipboard helper knows what to select when the Ctrl key is pressed.

How can I access and process nested objects, arrays or JSON?

This question is quite old, so as a contemporary update. With the onset of ES2015 there are alternatives to get a hold of the data you require. There is now a feature called object destructuring for accessing nested objects.

_x000D_
_x000D_
const data = {_x000D_
  code: 42,_x000D_
  items: [{_x000D_
    id: 1,_x000D_
    name: 'foo'_x000D_
  }, {_x000D_
    id: 2,_x000D_
    name: 'bar'_x000D_
  }]_x000D_
};_x000D_
_x000D_
const {_x000D_
  items: [, {_x000D_
    name: secondName_x000D_
  }]_x000D_
} = data;_x000D_
_x000D_
console.log(secondName);
_x000D_
_x000D_
_x000D_

The above example creates a variable called secondName from the name key from an array called items, the lonely , says skip the first object in the array.

Notably it's probably overkill for this example, as simple array acccess is easier to read, but it comes in useful when breaking apart objects in general.

This is very brief intro to your specific use case, destructuring can be an unusual syntax to get used to at first. I'd recommend reading Mozilla's Destructuring Assignment documentation to learn more.

Twitter Bootstrap scrollable table rows and fixed header

Interesting question, I tried doing this by just doing a fixed position row, but this way seems to be a much better one. Source at bottom.

css

thead { display:block; background: green; margin:0px; cell-spacing:0px; left:0px; }
tbody { display:block; overflow:auto; height:100px; }
th { height:50px; width:80px; }
td { height:50px; width:80px; background:blue; margin:0px; cell-spacing:0px;}

html

<table>
    <thead>
        <tr><th>hey</th><th>ho</th></tr>
    </thead>
    <tbody>
        <tr><td>test</td><td>test</td></tr>
        <tr><td>test</td><td>test</td></tr>
        <tr><td>test</td><td>test</td></tr>
</tbody>

http://www.imaputz.com/cssStuff/bigFourVersion.html

How to Extract Year from DATE in POSTGRESQL

This line solved my same problem in postgresql:

SELECT DATE_PART('year', column_name::date) from tableName;

If you want month, then simply replacing year with month solves that as well and likewise.

How can I get selector from jQuery object

Just add a layer over the $ function this way:

_x000D_
_x000D_
$ = (function(jQ) { _x000D_
 return (function() { _x000D_
  var fnc = jQ.apply(this,arguments);_x000D_
  fnc.selector = (arguments.length>0)?arguments[0]:null;_x000D_
  return fnc; _x000D_
 });_x000D_
})($);
_x000D_
_x000D_
_x000D_

Now you can do things like

$("a").selector
and will return "a" even on newer jQuery versions.

Create a file if one doesn't exist - C

You typically have to do this in a single syscall, or else you will get a race condition.

This will open for reading and writing, creating the file if necessary.

FILE *fp = fopen("scores.dat", "ab+");

If you want to read it and then write a new version from scratch, then do it as two steps.

FILE *fp = fopen("scores.dat", "rb");
if (fp) {
    read_scores(fp);
}

// Later...

// truncates the file
FILE *fp = fopen("scores.dat", "wb");
if (!fp)
    error();
write_scores(fp);

File path to resource in our war/WEB-INF folder?

I know this is late, but this is how I normally do it,

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();           
InputStream stream = classLoader.getResourceAsStream("../test/foo.txt");

set option "selected" attribute from dynamic created option

You're overthinking it:

var country = document.getElementById("country");
country.options[country.options.selectedIndex].selected = true;

Format number to always show 2 decimal places

Are you looking for floor?

var num = 1.42482;
var num2 = 1;
var fnum = Math.floor(num).toFixed(2);
var fnum2 = Math.floor(num2).toFixed(2);
alert(fnum + " and " + fnum2); //both values will be 1.00

How do I evenly add space between a label and the input field regardless of length of text?

You can always use the 'pre' tag inside the label, and just enter the blank spaces in it, So you can always add the same or different number of spaces you require

<form>
<label>First Name :<pre>Here just enter number of spaces you want to use(I mean using spacebar to enter blank spaces)</pre>
<input type="text"></label>
<label>Last Name :<pre>Now Enter enter number of spaces to match above number of 
spaces</pre>
<input type="text"></label>
</form>

Hope you like my answer, It's a simple and efficient hack

stopPropagation vs. stopImmediatePropagation

event.stopPropagation() allows other handlers on the same element to be executed, while event.stopImmediatePropagation() prevents every event from running. For example, see below jQuery code block.

$("p").click(function(event)
{ event.stopImmediatePropagation();
});
$("p").click(function(event)
{ // This function won't be executed 
$(this).css("color", "#fff7e3");
});

If event.stopPropagation was used in previous example, then the next click event on p element which changes the css will fire, but in case event.stopImmediatePropagation(), the next p click event will not fire.

Checking if a variable is an integer in PHP

Using is_numeric() for checking if a variable is an integer is a bad idea. This function will return TRUE for 3.14 for example. It's not the expected behavior.

To do this correctly, you can use one of these options:

Considering this variables array :

$variables = [
    "TEST 0" => 0,
    "TEST 1" => 42,
    "TEST 2" => 4.2,
    "TEST 3" => .42,
    "TEST 4" => 42.,
    "TEST 5" => "42",
    "TEST 6" => "a42",
    "TEST 7" => "42a",
    "TEST 8" => 0x24,
    "TEST 9" => 1337e0
];

The first option (FILTER_VALIDATE_INT way) :

# Check if your variable is an integer
if ( filter_var($variable, FILTER_VALIDATE_INT) === false ) {
  echo "Your variable is not an integer";
}

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

The second option (CASTING COMPARISON way) :

# Check if your variable is an integer
if ( strval($variable) !== strval(intval($variable)) ) {
  echo "Your variable is not an integer";
}

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

The third option (CTYPE_DIGIT way) :

# Check if your variable is an integer
if ( ! ctype_digit(strval($variable)) ) {
  echo "Your variable is not an integer";
}

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

The fourth option (REGEX way) :

# Check if your variable is an integer
if ( ! preg_match('/^\d+$/', $variable) ) {
  echo "Your variable is not an integer";
}

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

How do I specify a password to 'psql' non-interactively?

An alternative to using the PGPASSWORD environment variable is to use the conninfo string according to the documentation:

An alternative way to specify connection parameters is in a conninfo string or a URI, which is used instead of a database name. This mechanism give you very wide control over the connection.

$ psql "host=<server> port=5432 dbname=<db> user=<user> password=<password>"

postgres=>

Mean Squared Error in Numpy?

You can use:

mse = ((A - B)**2).mean(axis=ax)

Or

mse = (np.square(A - B)).mean(axis=ax)
  • with ax=0 the average is performed along the row, for each column, returning an array
  • with ax=1 the average is performed along the column, for each row, returning an array
  • with ax=None the average is performed element-wise along the array, returning a scalar value

OpenSSL and error in reading openssl.conf file

If openssl installation was successfull, search for "OPENSSL" in c drive to locate the config file and set the path.

set OPENSSL_CONF=<location where cnf is available>/openssl.cnf

It worked out for me.

Linux: command to open URL in default browser

For opening a URL in the browser through the terminal, CentOS 7 users can use gio open command. For example, if you want to open google.com then gio open https://www.google.com will open google.com URL in the browser.

xdg-open https://www.google.com will also work but this tool has been deprecated, Use gio open instead. I prefer this as this is the easiest way to open a URL using a command from the terminal.

how concatenate two variables in batch script?

The way is correct, but can be improved a bit with the extended set-syntax.

set "var=xyz"

Sets the var to the content until the last quotation mark, this ensures that no "hidden" spaces are appended.

Your code would look like

set "var1=A"
set "var2=B"
set "AB=hi"
set "newvar=%var1%%var2%"
echo %newvar% is the concat of var1 and var2
echo !%newvar%! is the indirect content of newvar

How do I reverse a C++ vector?

You can also use std::list instead of std::vector. list has a built-in function list::reverse for reversing elements.

React-router: How to manually invoke Link?

React Router v5 - React 16.8+ with Hooks (updated 09/23/2020)

If you're leveraging React Hooks, you can take advantage of the useHistory API that comes from React Router v5.

import React, {useCallback} from 'react';
import {useHistory} from 'react-router-dom';

export default function StackOverflowExample() {
  const history = useHistory();
  const handleOnClick = useCallback(() => history.push('/sample'), [history]);

  return (
    <button type="button" onClick={handleOnClick}>
      Go home
    </button>
  );
}

Another way to write the click handler if you don't want to use useCallback

const handleOnClick = () => history.push('/sample');

React Router v4 - Redirect Component

The v4 recommended way is to allow your render method to catch a redirect. Use state or props to determine if the redirect component needs to be shown (which then trigger's a redirect).

import { Redirect } from 'react-router';

// ... your class implementation

handleOnClick = () => {
  // some action...
  // then redirect
  this.setState({redirect: true});
}

render() {
  if (this.state.redirect) {
    return <Redirect push to="/sample" />;
  }

  return <button onClick={this.handleOnClick} type="button">Button</button>;
}

Reference: https://reacttraining.com/react-router/web/api/Redirect

React Router v4 - Reference Router Context

You can also take advantage of Router's context that's exposed to the React component.

static contextTypes = {
  router: PropTypes.shape({
    history: PropTypes.shape({
      push: PropTypes.func.isRequired,
      replace: PropTypes.func.isRequired
    }).isRequired,
    staticContext: PropTypes.object
  }).isRequired
};

handleOnClick = () => {
  this.context.router.push('/sample');
}

This is how <Redirect /> works under the hood.

Reference: https://github.com/ReactTraining/react-router/blob/master/packages/react-router/modules/Redirect.js#L46,L60

React Router v4 - Externally Mutate History Object

If you still need to do something similar to v2's implementation, you can create a copy of BrowserRouter then expose the history as an exportable constant. Below is a basic example but you can compose it to inject it with customizable props if needed. There are noted caveats with lifecycles, but it should always rerender the Router, just like in v2. This can be useful for redirects after an API request from an action function.

// browser router file...
import createHistory from 'history/createBrowserHistory';
import { Router } from 'react-router';

export const history = createHistory();

export default class BrowserRouter extends Component {
  render() {
    return <Router history={history} children={this.props.children} />
  }
}

// your main file...
import BrowserRouter from './relative/path/to/BrowserRouter';
import { render } from 'react-dom';

render(
  <BrowserRouter>
    <App/>
  </BrowserRouter>
);

// some file... where you don't have React instance references
import { history } from './relative/path/to/BrowserRouter';

history.push('/sample');

Latest BrowserRouter to extend: https://github.com/ReactTraining/react-router/blob/master/packages/react-router-dom/modules/BrowserRouter.js

React Router v2

Push a new state to the browserHistory instance:

import {browserHistory} from 'react-router';
// ...
browserHistory.push('/sample');

Reference: https://github.com/reactjs/react-router/blob/master/docs/guides/NavigatingOutsideOfComponents.md

What is difference between Axios and Fetch?

Fetch and Axios are very similar in functionality, but for more backwards compatibility Axios seems to work better (fetch doesn't work in IE 11 for example, check this post)

Also, if you work with JSON requests, the following are some differences I stumbled upon with.

Fetch JSON post request

let url = 'https://someurl.com';
let options = {
            method: 'POST',
            mode: 'cors',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json;charset=UTF-8'
            },
            body: JSON.stringify({
                property_one: value_one,
                property_two: value_two
            })
        };
let response = await fetch(url, options);
let responseOK = response && response.ok;
if (responseOK) {
    let data = await response.json();
    // do something with data
}

Axios JSON post request

let url = 'https://someurl.com';
let options = {
            method: 'POST',
            url: url,
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json;charset=UTF-8'
            },
            data: {
                property_one: value_one,
                property_two: value_two
            }
        };
let response = await axios(options);
let responseOK = response && response.status === 200 && response.statusText === 'OK';
if (responseOK) {
    let data = await response.data;
    // do something with data
}

So:

  • Fetch's body = Axios' data
  • Fetch's body has to be stringified, Axios' data contains the object
  • Fetch has no url in request object, Axios has url in request object
  • Fetch request function includes the url as parameter, Axios request function does not include the url as parameter.
  • Fetch request is ok when response object contains the ok property, Axios request is ok when status is 200 and statusText is 'OK'
  • To get the json object response: in fetch call the json() function on the response object, in Axios get data property of the response object.

Hope this helps.

How to overcome the CORS issue in ReactJS

The ideal way would be to add CORS support to your server.

You could also try using a separate jsonp module. As far as I know axios does not support jsonp. So I am not sure if the method you are using would qualify as a valid jsonp request.

There is another hackish work around for the CORS problem. You will have to deploy your code with an nginx server serving as a proxy for both your server and your client. The thing that will do the trick us the proxy_pass directive. Configure your nginx server in such a way that the location block handling your particular request will proxy_pass or redirect your request to your actual server. CORS problems usually occur because of change in the website domain. When you have a singly proxy serving as the face of you client and you server, the browser is fooled into thinking that the server and client reside in the same domain. Ergo no CORS.

Consider this example.

Your server is my-server.com and your client is my-client.com Configure nginx as follows:

// nginx.conf

upstream server {
    server my-server.com;
}

upstream client {
    server my-client.com;
}

server {
    listen 80;

    server_name my-website.com;
    access_log /path/to/access/log/access.log;
    error_log /path/to/error/log/error.log;

    location / {
        proxy_pass http://client;
    }

    location ~ /server/(?<section>.*) {
        rewrite ^/server/(.*)$ /$1 break;
        proxy_pass http://server;
    }
}

Here my-website.com will be the resultant name of the website where the code will be accessible (name of the proxy website). Once nginx is configured this way. You will need to modify the requests such that:

  • All API calls change from my-server.com/<API-path> to my-website.com/server/<API-path>

In case you are not familiar with nginx I would advise you to go through the documentation.

To explain what is happening in the configuration above in brief:

  • The upstreams define the actual servers to whom the requests will be redirected
  • The server block is used to define the actual behaviour of the nginx server.
  • In case there are multiple server blocks the server_name is used to identify the block which will be used to handle the current request.
  • The error_log and access_log directives are used to define the locations of the log files (used for debugging)
  • The location blocks define the handling of different types of requests:
    1. The first location block handles all requests starting with / all these requests are redirected to the client
    2. The second location block handles all requests starting with /server/<API-path>. We will be redirecting all such requests to the server.

Note: /server here is being used to distinguish the client side requests from the server side requests. Since the domain is the same there is no other way of distinguishing requests. Keep in mind there is no such convention that compels you to add /server in all such use cases. It can be changed to any other string eg. /my-server/<API-path>, /abc/<API-path>, etc.

Even though this technique should do the trick, I would highly advise you to add CORS support to the server as this is the ideal way situations like these should be handled.

If you wish to avoid doing all this while developing you could for this chrome extension. It should allow you to perform cross domain requests during development.

What's the proper way to install pip, virtualenv, and distribute for Python?

If you follow the steps advised in several tutorials I linked in this answer, you can get the desired effect without the somewhat complicated "manual" steps in Walker's and Vinay's answers. If you're on Ubuntu:

sudo apt-get install python-pip python-dev

The equivalent is achieved in OS X by using homebrew to install python (more details here).

brew install python

With pip installed, you can use it to get the remaining packages (you can omit sudo in OS X, as you're using your local python installation).

sudo pip install virtualenvwrapper

(these are the only packages you need installed globally and I doubt that it will clash with anything system-level from the OS. If you want to be super-safe, you can keep the distro's versions sudo apt-get install virtualenvwrapper)

Note: in Ubuntu 14.04 I receive some errors with pip install, so I use pip3 install virtualenv virtualenvwrapper and add VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 to my .bashrc/.zshrc file.

You then append to your .bashrc file

export WORKON_HOME
source /usr/local/bin/virtualenvwrapper.sh

and source it

. ~/.bashrc

This is basically it. Now the only decision is whether you want to create a virtualenv to include system-level packages

mkvirtualenv --system-site-packages foo

where your existing system packages don't have to be reinstalled, they are symlinked to the system interpreter's versions. Note: you can still install new packages and upgrade existing included-from-system packages without sudo - I tested it and it works without any disruptions of the system interpreter.

kermit@hocus-pocus:~$ sudo apt-get install python-pandas
kermit@hocus-pocus:~$ mkvirtualenv --system-site-packages s
(s)kermit@hocus-pocus:~$ pip install --upgrade pandas
(s)kermit@hocus-pocus:~$ python -c "import pandas; print(pandas.__version__)"
0.10.1
(s)kermit@hocus-pocus:~$ deactivate
kermit@hocus-pocus:~$ python -c "import pandas; print(pandas.__version__)"
0.8.0

The alternative, if you want a completely separated environment, is

mkvirtualenv --no-site-packages bar

or given that this is the default option, simply

mkvirtualenv bar

The result is that you have a new virtualenv where you can freely and sudolessly install your favourite packages

pip install flask

shorthand c++ if else statement

The basic syntax for using ternary operator is like this:

(condition) ? (if_true) : (if_false)

For you case it is like this:

number < 0 ? bigInt.sign = 0 : bigInt.sign = 1;

Real-world examples of recursion

I think that this really depends upon the language. In some languages, Lisp for example, recursion is often the natural response to a problem (and often with languages where this is the case, the compiler is optimized to deal with recursion).

The common pattern in Lisp of performing an operation on the first element of a list and then calling the function on the rest of the list in order to either accumulate a value or a new list is quite elegant and most natural way to do a lot of things in that language. In Java, not so much.

Simultaneously merge multiple data.frames in a list

Reduce makes this fairly easy:

merged.data.frame = Reduce(function(...) merge(..., all=T), list.of.data.frames)

Here's a fully example using some mock data:

set.seed(1)
list.of.data.frames = list(data.frame(x=1:10, a=1:10), data.frame(x=5:14, b=11:20), data.frame(x=sample(20, 10), y=runif(10)))
merged.data.frame = Reduce(function(...) merge(..., all=T), list.of.data.frames)
tail(merged.data.frame)
#    x  a  b         y
#12 12 NA 18        NA
#13 13 NA 19        NA
#14 14 NA 20 0.4976992
#15 15 NA NA 0.7176185
#16 16 NA NA 0.3841037
#17 19 NA NA 0.3800352

And here's an example using these data to replicate my.list:

merged.data.frame = Reduce(function(...) merge(..., by=match.by, all=T), my.list)
merged.data.frame[, 1:12]

#  matchname party st district chamber senate1993 name.x v2.x v3.x v4.x senate1994 name.y
#1   ALGIERE   200 RI      026       S         NA   <NA>   NA   NA   NA         NA   <NA>
#2     ALVES   100 RI      019       S         NA   <NA>   NA   NA   NA         NA   <NA>
#3    BADEAU   100 RI      032       S         NA   <NA>   NA   NA   NA         NA   <NA>

Note: It looks like this is arguably a bug in merge. The problem is there is no check that adding the suffixes (to handle overlapping non-matching names) actually makes them unique. At a certain point it uses [.data.frame which does make.unique the names, causing the rbind to fail.

# first merge will end up with 'name.x' & 'name.y'
merge(my.list[[1]], my.list[[2]], by=match.by, all=T)
# [1] matchname    party        st           district     chamber      senate1993   name.x      
# [8] votes.year.x senate1994   name.y       votes.year.y
#<0 rows> (or 0-length row.names)
# as there is no clash, we retain 'name.x' & 'name.y' and get 'name' again
merge(merge(my.list[[1]], my.list[[2]], by=match.by, all=T), my.list[[3]], by=match.by, all=T)
# [1] matchname    party        st           district     chamber      senate1993   name.x      
# [8] votes.year.x senate1994   name.y       votes.year.y senate1995   name         votes.year  
#<0 rows> (or 0-length row.names)
# the next merge will fail as 'name' will get renamed to a pre-existing field.

Easiest way to fix is to not leave the field renaming for duplicates fields (of which there are many here) up to merge. Eg:

my.list2 = Map(function(x, i) setNames(x, ifelse(names(x) %in% match.by,
      names(x), sprintf('%s.%d', names(x), i))), my.list, seq_along(my.list))

The merge/Reduce will then work fine.

How to add external library in IntelliJ IDEA?

Easier procedure on latest versions:

  • Copy jar to libs directory in the app (you can create the directory it if not there)
  • Refresh project so libs show up in the structure (right click on project top level, refresh/synchronize)
  • Expand libs and right click on the jar
  • Select "Add as Library"

Done

Warning about `$HTTP_RAW_POST_DATA` being deprecated

I just got the solution to this problem from a friend. he said: Add ob_start(); under your session code. You can add exit(); under the header. I tried it and it worked. Hope this helps

This is for those on a rented Hosting sever who do not have access to php.init file.

How can I run dos2unix on an entire directory?

find . -type f -print0 | xargs -0 dos2unix

Will recursively find all files inside current directory and call for these files dos2unix command

How do I edit a file after I shell to a Docker container?

For common edit operations I prefer to install vi (vim-tiny), which uses only 1491 kB or nano which uses 1707 kB.

In other hand vim uses 28.9 MB.

We have to remember that in order for apt-get install to work, we have to do the update the first time, so:

apt-get update
apt-get install vim-tiny

To start the editor in CLI we need to enter vi.

Count unique values in a column in Excel

Count unique with a condition. Col A is ID and using condition ID=32, Col B is Name and we are trying to count the unique names for a particular ID

=SUMPRODUCT((B2:B12<>"")*(A2:A12=32)/COUNTIF(B2:B12,B2:B12))

C char* to int conversion

Use atoi() from <stdlib.h>

http://linux.die.net/man/3/atoi

Or, write your own atoi() function which will convert char* to int

int a2i(const char *s)
{
  int sign=1;
  if(*s == '-'){
    sign = -1;
    s++;
  }
  int num=0;
  while(*s){
    num=((*s)-'0')+num*10;
    s++;   
  }
  return num*sign;
}

How might I force a floating DIV to match the height of another floating DIV?

Flex does this by default.

<div id="flex">
 <div id="response">
 </div> 
 <div id="note">
 </div>
</div>   

CSS:

#flex{display:flex}
#response{width:65%}
#note{width:35%}

https://jsfiddle.net/784pnojq/1/

BONUS: multiple rows

https://jsfiddle.net/784pnojq/2/

Iterating over a 2 dimensional python list

>>> mylist = [["%s,%s"%(i,j) for j in range(columns)] for i in range(rows)]
>>> mylist
[['0,0', '0,1', '0,2'], ['1,0', '1,1', '1,2'], ['2,0', '2,1', '2,2']]
>>> zip(*mylist)
[('0,0', '1,0', '2,0'), ('0,1', '1,1', '2,1'), ('0,2', '1,2', '2,2')]
>>> sum(zip(*mylist),())
('0,0', '1,0', '2,0', '0,1', '1,1', '2,1', '0,2', '1,2', '2,2')

SQL count rows in a table

Why don't you just right click on the table and then properties -> Storage and it would tell you the row count. You can use the below for row count in a view

SELECT SUM (row_count) 
FROM sys.dm_db_partition_stats 
WHERE object_id=OBJECT_ID('Transactions')    
AND (index_id=0 or index_id=1)`

Getting a 500 Internal Server Error on Laravel 5+ Ubuntu 14.04

Only change the web folder permission through this command:

sudo chmod 755 -R your_folder

Font from origin has been blocked from loading by Cross-Origin Resource Sharing policy

There is a nice writeup here.

Configuring this in nginx/apache is a mistake.
If you are using a hosting company you can't configure the edge.
If you are using Docker, the app should be self contained.

Note that some examples use connectHandlers but this only sets headers on the doc. Using rawConnectHandlers applies to all assets served (fonts/css/etc).

  // HSTS only the document - don't function over http.  
  // Make sure you want this as it won't go away for 30 days.
  WebApp.connectHandlers.use(function(req, res, next) {
    res.setHeader('Strict-Transport-Security', 'max-age=2592000; includeSubDomains'); // 2592000s / 30 days
    next();
  });

  // CORS all assets served (fonts/etc)
  WebApp.rawConnectHandlers.use(function(req, res, next) {
    res.setHeader('Access-Control-Allow-Origin', '*');
    return next();
  });

This would be a good time to look at browser policy like framing, etc.

User Authentication in ASP.NET Web API

I am working on a MVC5/Web API project and needed to be able to get authorization for the Web Api methods. When my index view is first loaded I make a call to the 'token' Web API method which I believe is created automatically.

The client side code (CoffeeScript) to get the token is:

getAuthenticationToken = (username, password) ->
    dataToSend = "username=" + username + "&password=" + password
    dataToSend += "&grant_type=password"
    $.post("/token", dataToSend).success saveAccessToken

If successful the following is called, which saves the authentication token locally:

saveAccessToken = (response) ->
    window.authenticationToken = response.access_token

Then if I need to make an Ajax call to a Web API method that has the [Authorize] tag I simply add the following header to my Ajax call:

{ "Authorization": "Bearer " + window.authenticationToken }

Decode Base64 data in Java

My solution is fastest and easiest.

public class MyBase64 {

    private final static char[] ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();

    private static int[]  toInt   = new int[128];

    static {
        for(int i=0; i< ALPHABET.length; i++){
            toInt[ALPHABET[i]]= i;
        }
    }

    /**
     * Translates the specified byte array into Base64 string.
     *
     * @param buf the byte array (not null)
     * @return the translated Base64 string (not null)
     */
    public static String encode(byte[] buf){
        int size = buf.length;
        char[] ar = new char[((size + 2) / 3) * 4];
        int a = 0;
        int i=0;
        while(i < size){
            byte b0 = buf[i++];
            byte b1 = (i < size) ? buf[i++] : 0;
            byte b2 = (i < size) ? buf[i++] : 0;

            int mask = 0x3F;
            ar[a++] = ALPHABET[(b0 >> 2) & mask];
            ar[a++] = ALPHABET[((b0 << 4) | ((b1 & 0xFF) >> 4)) & mask];
            ar[a++] = ALPHABET[((b1 << 2) | ((b2 & 0xFF) >> 6)) & mask];
            ar[a++] = ALPHABET[b2 & mask];
        }
        switch(size % 3){
            case 1: ar[--a]  = '=';
            case 2: ar[--a]  = '=';
        }
        return new String(ar);
    }

    /**
     * Translates the specified Base64 string into a byte array.
     *
     * @param s the Base64 string (not null)
     * @return the byte array (not null)
     */
    public static byte[] decode(String s){
        int delta = s.endsWith( "==" ) ? 2 : s.endsWith( "=" ) ? 1 : 0;
        byte[] buffer = new byte[s.length()*3/4 - delta];
        int mask = 0xFF;
        int index = 0;
        for(int i=0; i< s.length(); i+=4){
            int c0 = toInt[s.charAt( i )];
            int c1 = toInt[s.charAt( i + 1)];
            buffer[index++]= (byte)(((c0 << 2) | (c1 >> 4)) & mask);
            if(index >= buffer.length){
                return buffer;
            }
            int c2 = toInt[s.charAt( i + 2)];
            buffer[index++]= (byte)(((c1 << 4) | (c2 >> 2)) & mask);
            if(index >= buffer.length){
                return buffer;
            }
            int c3 = toInt[s.charAt( i + 3 )];
            buffer[index++]= (byte)(((c2 << 6) | c3) & mask);
        }
        return buffer;
    } 

}

Remove all files except some from a directory

rm !(textfile.txt|backup.tar.gz|script.php|database.sql|info.txt)

The extglob (Extended Pattern Matching) needs to be enabled in BASH (if it's not enabled):

shopt -s extglob

What are XAND and XOR

XOR (not neither and not both) B'0110' is the inverse (dual) of IFF (if and only if) B'1001'.

Jquery each - Stop loop and return object

Rather than setting a flag, it could be more elegant to use JavaScript's Array.prototype.find to find the matching item in the array. The loop will end as soon as a truthy value is returned from the callback, and the array value during that iteration will be the .find call's return value:

function findXX(word) {
    return someArray.find((item, i) => {
        $('body').append('-> '+i+'<br />');
        return item === word;
    }); 
}

_x000D_
_x000D_
const someArray = new Array();
someArray[0] = 't5';
someArray[1] = 'z12';
someArray[2] = 'b88';
someArray[3] = 's55';
someArray[4] = 'e51';
someArray[5] = 'o322';
someArray[6] = 'i22';
someArray[7] = 'k954';

var test = findXX('o322');
console.log('found word:', test);

function findXX(word) {
  return someArray.find((item, i) => {
    $('body').append('-> ' + i + '<br />');
    return item === word;
  });
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
_x000D_
_x000D_
_x000D_

how to change directory using Windows command line

Just type your desired drive initial in the command line and press enter

Like if you want to go L:\\ drive, Just type L: or l:

Get restaurants near my location

Is this what you are looking for?

https://maps.googleapis.com/maps/api/place/search/xml?location=49.260691,-123.137784&radius=500&sensor=false&key=*PlacesAPIKey*&types=restaurant

types is optional

Select specific row from mysql table

SET @customerID=0;
SELECT @customerID:=@customerID+1 AS customerID
FROM CUSTOMER ;

you can obtain the dataset from SQL like this and populate it into a java data structure (like a List) and then make the necessary sorting over there. (maybe with the help of a comparable interface)

What's the easiest way to escape HTML in Python?

cgi.escape should be good to escape HTML in the limited sense of escaping the HTML tags and character entities.

But you might have to also consider encoding issues: if the HTML you want to quote has non-ASCII characters in a particular encoding, then you would also have to take care that you represent those sensibly when quoting. Perhaps you could convert them to entities. Otherwise you should ensure that the correct encoding translations are done between the "source" HTML and the page it's embedded in, to avoid corrupting the non-ASCII characters.

Various ways to remove local Git changes

It all depends on exactly what you are trying to undo/revert. Start out by reading the post in Ube's link. But to attempt an answer:

Hard reset

git reset --hard [HEAD]

completely remove all staged and unstaged changes to tracked files.

I find myself often using hard resetting, when I'm like "just undo everything like if I had done a complete re-clone from the remote". In your case, where you just want your repo pristine, this would work.

Clean

git clean [-f]

Remove files that are not tracked.

For removing temporary files, but keep staged and unstaged changes to already tracked files. Most times, I would probably end up making an ignore-rule instead of repeatedly cleaning - e.g. for the bin/obj folders in a C# project, which you would usually want to exclude from your repo to save space, or something like that.

The -f (force) option will also remove files, that are not tracked and are also being ignored by git though ignore-rule. In the case above, with an ignore-rule to never track the bin/obj folders, even though these folders are being ignored by git, using the force-option will remove them from your file system. I've sporadically seen a use for this, e.g. when scripting deployment, and you want to clean your code before deploying, zipping or whatever.

Git clean will not touch files, that are already being tracked.

Checkout "dot"

git checkout .

I had actually never seen this notation before reading your post. I'm having a hard time finding documentation for this (maybe someone can help), but from playing around a bit, it looks like it means:

"undo all changes in my working tree".

I.e. undo unstaged changes in tracked files. It apparently doesn't touch staged changes and leaves untracked files alone.

Stashing

Some answers mention stashing. As the wording implies, you would probably use stashing when you are in the middle of something (not ready for a commit), and you have to temporarily switch branches or somehow work on another state of your code, later to return to your "messy desk". I don't see this applies to your question, but it's definitely handy.

To sum up

Generally, if you are confident you have committed and maybe pushed to a remote important changes, if you are just playing around or the like, using git reset --hard HEAD followed by git clean -f will definitively cleanse your code to the state, it would be in, had it just been cloned and checked out from a branch. It's really important to emphasize, that the resetting will also remove staged, but uncommitted changes. It will wipe everything that has not been committed (except untracked files, in which case, use clean).

All the other commands are there to facilitate more complex scenarios, where a granularity of "undoing stuff" is needed :)

I feel, your question #1 is covered, but lastly, to conclude on #2: the reason you never found the need to use git reset --hard was that you had never staged anything. Had you staged a change, neither git checkout . nor git clean -f would have reverted that.

Hope this covers.

What’s the difference between “{}” and “[]” while declaring a JavaScript array?

Syntax of JSON

object = {} | { members }

  • members = pair | pair, members
  • pair = string : value

array = [] | [ elements ]

  • elements = value | value elements

value = string|number|object|array|true|false|null

jackson deserialization json to java-objects

 JsonNode node = mapper.readValue("[{\"id\":\"value11\",\"name\": \"value12\",\"qty\":\"value13\"},"

 System.out.println("id : "+node.findValues("id").get(0).asText());

this also done the trick.

Python Pandas: How to read only first n rows of CSV files in?

If you only want to read the first 999,999 (non-header) rows:

read_csv(..., nrows=999999)

If you only want to read rows 1,000,000 ... 1,999,999

read_csv(..., skiprows=1000000, nrows=999999)

nrows : int, default None Number of rows of file to read. Useful for reading pieces of large files*

skiprows : list-like or integer Row numbers to skip (0-indexed) or number of rows to skip (int) at the start of the file

and for large files, you'll probably also want to use chunksize:

chunksize : int, default None Return TextFileReader object for iteration

pandas.io.parsers.read_csv documentation

Which TensorFlow and CUDA version combinations are compatible?

I had a similar problem after upgrading to TF 2.0. The CUDA version that TF was reporting did not match what Ubuntu 18.04 thought I had installed. It said I was using CUDA 7.5.0, but apt thought I had the right version installed.

What I eventually had to do was grep recursively in /usr/local for CUDNN_MAJOR, and I found that /usr/local/cuda-10.0/targets/x86_64-linux/include/cudnn.h did indeed specify the version as 7.5.0.
/usr/local/cuda-10.1 got it right, and /usr/local/cuda pointed to /usr/local/cuda-10.1, so it was (and remains) a mystery to me why TF was looking at /usr/local/cuda-10.0.

Anyway, I just moved /usr/local/cuda-10.0 to /usr/local/old-cuda-10.0 so TF couldn't find it any more and everything then worked like a charm.

It was all very frustrating, and I still feel like I just did a random hack. But it worked :) and perhaps this will help someone with a similar issue.

Read files from a Folder present in project

below code should work:

string path = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), @"Data\Names.txt");
string[] files = File.ReadAllLines(path);

Connecting to SQL Server Express - What is my server name?

If sql server is installed on your machine, you should check

Programs -> Microsoft SQL Server 20XX -> Configuration Tools -> SQL Server Configuration Manager -> SQL Server Services You'll see "SQL Server (MSSQLSERVER)"

Programs -> Microsoft SQL Server 20XX -> Configuration Tools -> SQL Server Configuration Manager -> SQL Server Network Configuration -> Protocols for MSSQLSERVER -> TCP/IP Make sure it's using port number 1433

If you want to see if the port is open and listening try this from your command prompt... telnet 127.0.0.1 1433

And yes, SQL Express installs use localhost\SQLEXPRESS as the instance name by default.

what is the differences between sql server authentication and windows authentication..?

If you wish to authenticate the users against windows system users [created by Administrator] then in that case you will go for Windows Authentication in your Application.

But in case you want to authenticate the users against set of users available in your application database, then in that case you will want to go for SQL Authentication.

Precisely if your application is an ASP.NET web-app, then you can use standard Login controls which depend on Providers like SqlMembershipProvider, SqlProfileProvider. You can configure your login controls and your application whether it should authenticate against windows users or app-database users. In the first case it will be called Windows Authentication and the later will be known as Sql Authentication.

Get parent directory of running script

I Hope this will help you.

echo getcwd().'<br>'; // getcwd() will return current working directory
echo dirname(getcwd(),1).'<br>';
echo dirname(getcwd(),2).'<br>';
echo dirname(getcwd(),3).'<br>';

Output :

C:\wamp64\www\public_html\step
C:\wamp64\www\public_html
C:\wamp64\www
C:\wamp64

How do I show my global Git configuration?

If you just want to list one part of the Git configuration, such as alias, core, remote, etc., you could just pipe the result through grep. Something like:

git config --global -l | grep core

Python: Find index of minimum item in list of floats

Use of the argmin method for numpy arrays.

import numpy as np
np.argmin(myList)

However, it is not the fastest method: it is 3 times slower than OP's answer on my computer. It may be the most concise one though.

Setting up a cron job in Windows

There's pycron which I really as a Cron implementation for windows, but there's also the built in scheduler which should work just fine for what you need (Control Panel -> Scheduled Tasks -> Add Scheduled Task).

count distinct values in spreadsheet

=UNIQUE({filter(Core!L8:L27,isblank(Core!L8:L27)=false),query(ArrayFormula(countif(Core!L8:L27,Core!L8:L27)),"select Col1 where Col1 <> 0")})

Core!L8:L27 = list

How to Use UTF-8 Collation in SQL Server database?

Two UDF to deal with UTF-8 in T-SQL:

CREATE Function UcsToUtf8(@src nvarchar(MAX)) returns varchar(MAX) as
begin
    declare @res varchar(MAX)='', @pi char(8)='%[^'+char(0)+'-'+char(127)+']%', @i int, @j int
    select @i=patindex(@pi,@src collate Latin1_General_BIN)
    while @i>0
    begin
        select @j=unicode(substring(@src,@i,1))
        if @j<0x800     select @res=@res+left(@src,@i-1)+char((@j&1984)/64+192)+char((@j&63)+128)
        else            select @res=@res+left(@src,@i-1)+char((@j&61440)/4096+224)+char((@j&4032)/64+128)+char((@j&63)+128)
        select @src=substring(@src,@i+1,datalength(@src)-1), @i=patindex(@pi,@src collate Latin1_General_BIN)
    end
    select @res=@res+@src
    return @res
end

CREATE Function Utf8ToUcs(@src varchar(MAX)) returns nvarchar(MAX) as
begin
    declare @i int, @res nvarchar(MAX)=@src, @pi varchar(18)
    select @pi='%[à-ï][€-¿][€-¿]%',@i=patindex(@pi,@src collate Latin1_General_BIN)
    while @i>0 select @res=stuff(@res,@i,3,nchar(((ascii(substring(@src,@i,1))&31)*4096)+((ascii(substring(@src,@i+1,1))&63)*64)+(ascii(substring(@src,@i+2,1))&63))), @src=stuff(@src,@i,3,'.'), @i=patindex(@pi,@src collate Latin1_General_BIN)
    select @pi='%[Â-ß][€-¿]%',@i=patindex(@pi,@src collate Latin1_General_BIN)
    while @i>0 select @res=stuff(@res,@i,2,nchar(((ascii(substring(@src,@i,1))&31)*64)+(ascii(substring(@src,@i+1,1))&63))), @src=stuff(@src,@i,2,'.'),@i=patindex(@pi,@src collate Latin1_General_BIN)
    return @res
end

python: get directory two levels up

You can use pathlib. Unfortunately this is only available in the stdlib for Python 3.4. If you have an older version you'll have to install a copy from PyPI here. This should be easy to do using pip.

from pathlib import Path

p = Path(__file__).parents[1]

print(p)
# /absolute/path/to/two/levels/up

This uses the parents sequence which provides access to the parent directories and chooses the 2nd one up.

Note that p in this case will be some form of Path object, with their own methods. If you need the paths as string then you can call str on them.

Mockito, JUnit and Spring

The difference in whether you have to instantiate your @InjectMocks annotated field is in the version of Mockito, not in whether you use the MockitoJunitRunner or MockitoAnnotations.initMocks. In 1.9, which will also handle some constructor injection of your @Mock fields, it will do the instantiation for you. In earlier versions, you have to instantiate it yourself.

This is how I do unit testing of my Spring beans. There is no problem. People run into confusion when they want to use Spring configuration files to actually do the injection of the mocks, which is crossing up the point of unit tests and integration tests.

And of course the unit under test is an Impl. You need to test a real concrete thing, right? Even if you declared it as an interface you would have to instantiate the real thing to test it. Now, you could get into spies, which are stub/mock wrappers around real objects, but that should be for corner cases.

ClassCastException, casting Integer to Double

We can cast an int to a double but we can't do the same with the wrapper classes Integer and Double:

 int     a = 1;
 Integer b = 1;   // inboxing, requires Java 1.5+

 double  c = (double) a;   // OK
 Double  d = (Double) b;   // No way.

This shows the compile time error that corresponds to your runtime exception.

How to make Java honor the DNS Caching Timeout?

So I decided to look at the java source code because I found official docs a bit confusing. And what I found (for OpenJDK 11) mostly aligns with what others have written. What is important is the order of evaluation of properties.

InetAddressCachePolicy.java (I'm omitting some boilerplate for readability):


String tmpString = Security.getProperty("networkaddress.cache.ttl");
if (tmpString != null) {
   tmp = Integer.valueOf(tmpString);
   return;
}
...
String tmpString = System.getProperty("sun.net.inetaddr.ttl");
if (tmpString != null) {
   tmp = Integer.valueOf(tmpString);
   return;
}
...
if (tmp != null) {
  cachePolicy = tmp < 0 ? FOREVER : tmp;
  propertySet = true;
} else {
  /* No properties defined for positive caching. If there is no
  * security manager then use the default positive cache value.
  */
  if (System.getSecurityManager() == null) {
    cachePolicy = 30;
  }
}

You can clearly see that the security property is evaluated first, system property second and if any of them is set cachePolicy value is set to that number or -1 (FOREVER) if they hold a value that is bellow -1. If nothing is set it defaults to 30 seconds. As it turns out for OpenJDK that is almost always the case because by default java.security does not set that value, only a negative one.

#networkaddress.cache.ttl=-1 <- this line is commented out
networkaddress.cache.negative.ttl=10

BTW if the networkaddress.cache.negative.ttl is not set (removed from the file) the default inside the java class is 0. Documentation is wrong in this regard. This is what tripped me over.

How to use java.net.URLConnection to fire and handle HTTP requests?

Initially I was misled by this article which favours HttpClient.

Later I have been realized that HttpURLConnection is going to stay from this article

As per the Google blog:

Apache HTTP client has fewer bugs on Eclair and Froyo. It is the best choice for these releases. For Gingerbread , HttpURLConnection is the best choice. Its simple API and small size makes it great fit for Android.

Transparent compression and response caching reduce network use, improve speed and save battery. New applications should use HttpURLConnection; it is where we will be spending our energy going forward.

After reading this article and some other stack over flow questions, I am convinced that HttpURLConnection is going to stay for longer durations.

Some of the SE questions favouring HttpURLConnections:

On Android, make a POST request with URL Encoded Form data without using UrlEncodedFormEntity

HttpPost works in Java project, not in Android

How to implement a SQL like 'LIKE' operator in java?

public static boolean like(String toBeCompare, String by){
    if(by != null){
        if(toBeCompare != null){
            if(by.startsWith("%") && by.endsWith("%")){
                int index = toBeCompare.toLowerCase().indexOf(by.replace("%", "").toLowerCase());
                if(index < 0){
                    return false;
                } else {
                    return true;
                }
            } else if(by.startsWith("%")){
                return toBeCompare.endsWith(by.replace("%", ""));
            } else if(by.endsWith("%")){
                return toBeCompare.startsWith(by.replace("%", ""));
            } else {
                return toBeCompare.equals(by.replace("%", ""));
            }
        } else {
            return false;
        }
    } else {
        return false;
    }
}

may be help you

Representing null in JSON

null is not zero. It is not a value, per se: it is a value outside the domain of the variable indicating missing or unknown data.

There is only one way to represent null in JSON. Per the specs (RFC 4627 and json.org):

2.1.  Values

A JSON value MUST be an object, array, number, or string, or one of
the following three literal names:

  false null true

enter image description here

What are major differences between C# and Java?

C# has automatic properties which are incredibly convenient and they also help to keep your code cleaner, at least when you don't have custom logic in your getters and setters.

Remove excess whitespace from within a string

Not sure exactly what you want but here are two situations:

  1. If you are just dealing with excess whitespace on the beginning or end of the string you can use trim(), ltrim() or rtrim() to remove it.

  2. If you are dealing with extra spaces within a string consider a preg_replace of multiple whitespaces " "* with a single whitespace " ".

Example:

$foo = preg_replace('/\s+/', ' ', $foo);