Programs & Examples On #Framemaker

Can I set an unlimited length for maxJsonLength in web.config?

you can write this line into Controller

json.MaxJsonLength = 2147483644;

you can also write this line into web.config

<configuration>
  <system.web.extensions>
    <scripting>
        <webServices>
            <jsonSerialization maxJsonLength="2147483647">
            </jsonSerialization>
        </webServices>
    </scripting>
  </system.web.extensions>

`

To be on the safe side, use both.

How to select element using XPATH syntax on Selenium for Python?

HTML

<div id='a'>
  <div>
    <a class='click'>abc</a>
  </div>
</div>

You could use the XPATH as :

//div[@id='a']//a[@class='click']

output

<a class="click">abc</a>

That said your Python code should be as :

driver.find_element_by_xpath("//div[@id='a']//a[@class='click']")

Html5 Placeholders with .NET MVC 3 Razor EditorFor extension?

I've wrote such a simple class:

public static class WatermarkExtension
{
    public static MvcHtmlString WatermarkFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
    {
        var watermark = ModelMetadata.FromLambdaExpression(expression, html.ViewData).Watermark;
        var htmlEncoded = HttpUtility.HtmlEncode(watermark);
        return new MvcHtmlString(htmlEncoded);
    }
}

The usage as such:

@Html.TextBoxFor(model => model.AddressSuffix, new {placeholder = Html.WatermarkFor(model => model.AddressSuffix)})

And property in a viewmodel:

[Display(ResourceType = typeof (Resources), Name = "AddressSuffixLabel", Prompt = "AddressSuffixPlaceholder")]
public string AddressSuffix
{
    get { return _album.AddressSuffix; }
    set { _album.AddressSuffix = value; }
}

Notice Prompt parameter. In this case I use strings from resources for localization but you can use just strings, just avoid ResourceType parameter.

How get total sum from input box values using Javascript?

Try this:

function add() 
{
  var sum = 0;
  var inputs = document.getElementsByTagName("input");
  for(i = 0; i <= inputs.length; i++) 
  {
   if( inputs[i].name == 'qty'+i) 
   {
     sum += parseInt(input[i].value);
   }
  }
  console.log(sum)

}

Install a Windows service using a Windows command prompt?

Perform the following:

  1. Start up the command prompt (CMD) with administrator rights.
  2. Type c:\windows\microsoft.net\framework\v4.0.30319\installutil.exe [your windows service path to exe]
  3. Press return and that's that!

It's important to open with administrator rights otherwise you may find errors that come up that don't make sense. If you get any, check you've opened it with admin rights first!

To open with admin rights, right click 'Command Prompt' and select 'Run as administrator'.

Source: http://coderamblings.wordpress.com/2012/07/24/how-to-install-a-windows-service-using-the-command-prompt/

Have log4net use application config file for configuration data

All appender names must be reflected in the root section.
In your case the appender name is EventLogAppender but in the <root> <appender-ref .. section it is named as ConsoleAppender. They need to match.

You can add multiple appenders to your log config but you need to register each of them in the <root> section.

<appender-ref ref="ConsoleAppender" />
<appender-ref ref="EventLogAppender" />

You can also refer to the apache documentation on configuring log4net.

How to check if a String contains any letter from a to z?

Replace your for loop by this :

errorCounter = Regex.Matches(yourstring,@"[a-zA-Z]").Count;

Remember to use Regex class, you have to using System.Text.RegularExpressions; in your import

How are SSL certificate server names resolved/Can I add alternative names using keytool?

How host name verification should be done is defined in RFC 6125, which is quite recent and generalises the practice to all protocols, and replaces RFC 2818, which was specific to HTTPS. (I'm not even sure Java 7 uses RFC 6125, which might be too recent for this.)

From RFC 2818 (Section 3.1):

If a subjectAltName extension of type dNSName is present, that MUST be used as the identity. Otherwise, the (most specific) Common Name field in the Subject field of the certificate MUST be used. Although the use of the Common Name is existing practice, it is deprecated and Certification Authorities are encouraged to use the dNSName instead.

[...]

In some cases, the URI is specified as an IP address rather than a hostname. In this case, the iPAddress subjectAltName must be present in the certificate and must exactly match the IP in the URI.

Essentially, the specific problem you have comes from the fact that you're using IP addresses in your CN and not a host name. Some browsers might work because not all tools follow this specification strictly, in particular because "most specific" in RFC 2818 isn't clearly defined (see discussions in RFC 6215).

If you're using keytool, as of Java 7, keytool has an option to include a Subject Alternative Name (see the table in the documentation for -ext): you could use -ext san=dns:www.example.com or -ext san=ip:10.0.0.1.

EDIT:

You can request a SAN in OpenSSL by changing openssl.cnf (it will pick the copy in the current directory if you don't want to edit the global configuration, as far as I remember, or you can choose an explicit location using the OPENSSL_CONF environment variable).

Set the following options (find the appropriate sections within brackets first):

[req]
req_extensions = v3_req

[ v3_req ]
subjectAltName=IP:10.0.0.1
# or subjectAltName=DNS:www.example.com

There's also a nice trick to use an environment variable for this (rather in than fixing it in a configuration file) here: http://www.crsr.net/Notes/SSL.html

CodeIgniter: 404 Page Not Found on Live Server

I had the same problem. Changing controlers first letter to uppercase helped.

Swift: Reload a View Controller

This might be a little late, but did you try calling loadView()?

Angular 2 Date Input not binding to date value

In your component

let today: string;

ngOnInit() {
  this.today = new Date().toISOString().split('T')[0];
}

and in your html file

<input name="date" [(ngModel)]="today" type="date" required>

Get selected element's outer HTML

Pure JavaScript:

var outerHTML = function(node) {
  var div = document.createElement("div");
  div.appendChild(node.cloneNode(true));
  return div.innerHTML;
};

Git: force user and password prompt

Add a -v flag with your git command . e.g. git pull -v

v stands for verify .

System.MissingMethodException: Method not found?

It's also possible the problem is with a parameter or return type of the method that's reported missing, and the "missing" method per se is fine.

That's what was happening in my case, and the misleading message made it take much longer to figure out the issue. It turns out the assembly for a parameter's type had an older version in the GAC, but the older version actually had a higher version number due to a change in version numbering schemes used. Removing that older/higher version from the GAC fixed the problem.

MySQL WHERE: how to write "!=" or "not equals"?

The != operator most certainly does exist! It is an alias for the standard <> operator.

Perhaps your fields are not actually empty strings, but instead NULL?

To compare to NULL you can use IS NULL or IS NOT NULL or the null safe equals operator <=>.

multiprocessing.Pool: When to use apply, apply_async or map?

Back in the old days of Python, to call a function with arbitrary arguments, you would use apply:

apply(f,args,kwargs)

apply still exists in Python2.7 though not in Python3, and is generally not used anymore. Nowadays,

f(*args,**kwargs)

is preferred. The multiprocessing.Pool modules tries to provide a similar interface.

Pool.apply is like Python apply, except that the function call is performed in a separate process. Pool.apply blocks until the function is completed.

Pool.apply_async is also like Python's built-in apply, except that the call returns immediately instead of waiting for the result. An AsyncResult object is returned. You call its get() method to retrieve the result of the function call. The get() method blocks until the function is completed. Thus, pool.apply(func, args, kwargs) is equivalent to pool.apply_async(func, args, kwargs).get().

In contrast to Pool.apply, the Pool.apply_async method also has a callback which, if supplied, is called when the function is complete. This can be used instead of calling get().

For example:

import multiprocessing as mp
import time

def foo_pool(x):
    time.sleep(2)
    return x*x

result_list = []
def log_result(result):
    # This is called whenever foo_pool(i) returns a result.
    # result_list is modified only by the main process, not the pool workers.
    result_list.append(result)

def apply_async_with_callback():
    pool = mp.Pool()
    for i in range(10):
        pool.apply_async(foo_pool, args = (i, ), callback = log_result)
    pool.close()
    pool.join()
    print(result_list)

if __name__ == '__main__':
    apply_async_with_callback()

may yield a result such as

[1, 0, 4, 9, 25, 16, 49, 36, 81, 64]

Notice, unlike pool.map, the order of the results may not correspond to the order in which the pool.apply_async calls were made.


So, if you need to run a function in a separate process, but want the current process to block until that function returns, use Pool.apply. Like Pool.apply, Pool.map blocks until the complete result is returned.

If you want the Pool of worker processes to perform many function calls asynchronously, use Pool.apply_async. The order of the results is not guaranteed to be the same as the order of the calls to Pool.apply_async.

Notice also that you could call a number of different functions with Pool.apply_async (not all calls need to use the same function).

In contrast, Pool.map applies the same function to many arguments. However, unlike Pool.apply_async, the results are returned in an order corresponding to the order of the arguments.

python 2 instead of python 3 as the (temporary) default python?

mkdir ~/bin
PATH=~/bin:$PATH
ln -s /usr/bin/python2 ~/bin/python

To stop using python2, exit or rm ~/bin/python.

Having issues with a MySQL Join that needs to meet multiple conditions

You can group conditions with parentheses. When you are checking if a field is equal to another, you want to use OR. For example WHERE a='1' AND (b='123' OR b='234').

SELECT u.*
FROM rooms AS u
JOIN facilities_r AS fu
ON fu.id_uc = u.id_uc AND (fu.id_fu='4' OR fu.id_fu='3')
WHERE vizibility='1'
GROUP BY id_uc
ORDER BY u_premium desc, id_uc desc

Kill Attached Screen in Linux

From Screen User's Manual ;

screen -d -r "screenName"

Reattach a session and if necessary detach it first

Output (echo/print) everything from a PHP Array

You can use print_r to get human-readable output.

See http://www.php.net/print_r

Writing Python lists to columns in csv

You can use izip to combine your lists, and then iterate them

for val in itertools.izip(l1,l2,l3,l4,l5):
    writer.writerow(val)

RecyclerView expand/collapse items

I know it has been a long time since the original question was posted. But i think for slow ones like me a bit of explanation of @Heisenberg's answer would help.

Declare two variable in the adapter class as

private int mExpandedPosition= -1;
private RecyclerView recyclerView = null;

Then in onBindViewHolder following as given in the original answer.

      // This line checks if the item displayed on screen 
      // was expanded or not (Remembering the fact that Recycler View )
      // reuses views so onBindViewHolder will be called for all
      // items visible on screen.
    final boolean isExpanded = position==mExpandedPosition;

        //This line hides or shows the layout in question
        holder.details.setVisibility(isExpanded?View.VISIBLE:View.GONE);

        // I do not know what the heck this is :)
        holder.itemView.setActivated(isExpanded);

        // Click event for each item (itemView is an in-built variable of holder class)
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

 // if the clicked item is already expaned then return -1 
//else return the position (this works with notifyDatasetchanged )
                mExpandedPosition = isExpanded ? -1:position;
    // fancy animations can skip if like
                TransitionManager.beginDelayedTransition(recyclerView);
    //This will call the onBindViewHolder for all the itemViews on Screen
                notifyDataSetChanged();
            }
        });

And lastly to get the recyclerView object in the adapter override

@Override
public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);

    this.recyclerView = recyclerView;
}

Hope this Helps.

auto create database in Entity Framework Core

For EF Core 2.0+ I had to take a different approach because they changed the API. As of March 2019 Microsoft recommends you put your database migration code in your application entry class but outside of the WebHost build code.

public class Program
{
    public static void Main(string[] args)
    {
        var host = CreateWebHostBuilder(args).Build();
        using (var serviceScope = host.Services.CreateScope())
        {
            var context = serviceScope.ServiceProvider.GetRequiredService<PersonContext>();
            context.Database.Migrate();
        }
        host.Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>();
}

how to change default python version?

you can change temporarily or switch between different versions using following commands:

set path=C:\Users\Shaina\AppData\Local\Programs\Python\Python35-32;%PATH%
python --version

enter image description here

inline conditionals in angular.js

I'll throw mine in the mix:

https://gist.github.com/btm1/6802312

this evaluates the if statement once and adds no watch listener BUT you can add an additional attribute to the element that has the set-if called wait-for="somedata.prop" and it will wait for that data or property to be set before evaluating the if statement once. that additional attribute can be very handy if you're waiting for data from an XHR request.

angular.module('setIf',[]).directive('setIf',function () {
    return {
      transclude: 'element',
      priority: 1000,
      terminal: true,
      restrict: 'A',
      compile: function (element, attr, linker) {
        return function (scope, iterStartElement, attr) {
          if(attr.waitFor) {
            var wait = scope.$watch(attr.waitFor,function(nv,ov){
              if(nv) {
                build();
                wait();
              }
            });
          } else {
            build();
          }

          function build() {
            iterStartElement[0].doNotMove = true;
            var expression = attr.setIf;
            var value = scope.$eval(expression);
            if (value) {
              linker(scope, function (clone) {
                iterStartElement.after(clone);
                clone.removeAttr('set-if');
                clone.removeAttr('wait-for');
              });
            }
          }
        };
      }
    };
  });

Convert string (without any separator) to list

You can use the re module:

import re
re.sub(r'\D', '', '+123-456-7890')

This will replace all non-digits with ''.

How do I include negative decimal numbers in this regular expression?

UPDATED(13/08/2014): This is the best code for positive and negative numbers =)

(^-?0\.[0-9]*[1-9]+[0-9]*$)|(^-?[1-9]+[0-9]*((\.[0-9]*[1-9]+[0-9]*$)|(\.[0-9]+)))|(^-?[1-9]+[0-9]*$)|(^0$){1}

I tried with this numbers and works fine:

-1234454.3435
-98.99
-12.9
-12.34
-10.001
-3
-0.001
-000
-0.00
0
0.00
00000001.1
0.01
1201.0000001
1234454.3435
7638.98701

Get file content from URL?

Use file_get_contents in combination with json_decode and echo.

Delete all data rows from an Excel table (apart from the first)

This is how I clear the data:

Sub Macro3()
    With Sheet1.ListObjects("Table1")
        If Not .DataBodyRange Is Nothing Then
            .DataBodyRange.Delete
        End If
    End With
End Sub

How to loop through an array containing objects and access their properties

Here's an example on how you can do it :)

_x000D_
_x000D_
var students = [{_x000D_
    name: "Mike",_x000D_
    track: "track-a",_x000D_
    achievements: 23,_x000D_
    points: 400,_x000D_
  },_x000D_
  {_x000D_
    name: "james",_x000D_
    track: "track-a",_x000D_
    achievements: 2,_x000D_
    points: 21,_x000D_
  },_x000D_
]_x000D_
_x000D_
students.forEach(myFunction);_x000D_
_x000D_
function myFunction(item, index) {_x000D_
  for (var key in item) {_x000D_
    console.log(item[key])_x000D_
  }_x000D_
}
_x000D_
_x000D_
_x000D_

MomentJS getting JavaScript Date in UTC

Calling toDate will create a copy (the documentation is down-right wrong about it not being a copy), of the underlying JS Date object. JS Date object is stored in UTC and will always print to eastern time. Without getting into whether .utc() modifies the underlying object that moment wraps use the code below.

You don't need moment for this.

new Date().getTime()

This works, because JS Date at its core is in UTC from the Unix Epoch. It's extraordinarily confusing and I believe a big flaw in the interface to mix local and UTC times like this with no descriptions in the methods.

Cursor adapter and sqlite example

Really simple example.

Here is a really simple, but very effective, example. Once you have the basics down you can easily build off of it.

There are two main parts to using a Cursor Adapter with SQLite:

  1. Create a proper Cursor from the Database.

  2. Create a custom Cursor Adapter that takes the Cursor data from the database and pairs it with the View you intend to represent the data with.

1. Create a proper Cursor from the Database.

In your Activity:

SQLiteOpenHelper sqLiteOpenHelper = new SQLiteOpenHelper( 
        context, DATABASE_NAME, null, DATABASE_VERSION);

SQLiteDatabase sqLiteDatabase = sqLiteOpenHelper.getReadableDatabase();

String query = "SELECT * FROM clients ORDER BY company_name ASC"; // No trailing ';'

Cursor cursor = sqLiteDatabase.rawQuery(query, null); 

ClientCursorAdapter adapter = new ClientCursorAdapter(
        this, R.layout.clients_listview_row, cursor, 0 );

this.setListAdapter(adapter);

2. Create a Custom Cursor Adapter.

Note: Extending from ResourceCursorAdapter assumes you use XML to create your views.

public class ClientCursorAdapter extends ResourceCursorAdapter {

    public ClientCursorAdapter(Context context, int layout, Cursor cursor, int flags) {
        super(context, layout, cursor, flags);
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        TextView name = (TextView) view.findViewById(R.id.name);
        name.setText(cursor.getString(cursor.getColumnIndex("name")));

        TextView phone = (TextView) view.findViewById(R.id.phone);
        phone.setText(cursor.getString(cursor.getColumnIndex("phone")));
    }
}

Import MySQL database into a MS SQL Server

Here is my approach for importing .sql files to MS SQL:

  1. Export table from MySQL with --compatible=mssql and --extended-insert=FALSE options:

    mysqldump -u [username] -p --compatible=mssql --extended-insert=FALSE db_name table_name > table_backup.sql

  2. Split the exported file with PowerShell by 300000 lines per file:

    $i=0; Get-Content exported.sql -ReadCount 300000 | %{$i++; $_ | Out-File out_$i.sql}

  3. Run each file in MS SQL Server Management Studio

There are few tips how to speed up the inserts.

Other approach is to use mysqldump –where option. By using this option you can split your table on any condition which is supported by where sql clause.

Best way to return a value from a python script

If you want your script to return values, just do return [1,2,3] from a function wrapping your code but then you'd have to import your script from another script to even have any use for that information:

Return values (from a wrapping-function)

(again, this would have to be run by a separate Python script and be imported in order to even do any good):

import ...
def main():
    # calculate stuff
    return [1,2,3]

Exit codes as indicators

(This is generally just good for when you want to indicate to a governor what went wrong or simply the number of bugs/rows counted or w/e. Normally 0 is a good exit and >=1 is a bad exit but you could inter-prate them in any way you want to get data out of it)

import sys
# calculate and stuff
sys.exit(100)

And exit with a specific exit code depending on what you want that to tell your governor. I used exit codes when running script by a scheduling and monitoring environment to indicate what has happened.

(os._exit(100) also works, and is a bit more forceful)

Stdout as your relay

If not you'd have to use stdout to communicate with the outside world (like you've described). But that's generally a bad idea unless it's a parser executing your script and can catch whatever it is you're reporting to.

import sys
# calculate stuff
sys.stdout.write('Bugs: 5|Other: 10\n')
sys.stdout.flush()
sys.exit(0)

Are you running your script in a controlled scheduling environment then exit codes are the best way to go.

Files as conveyors

There's also the option to simply write information to a file, and store the result there.

# calculate
with open('finish.txt', 'wb') as fh:
    fh.write(str(5)+'\n')

And pick up the value/result from there. You could even do it in a CSV format for others to read simplistically.

Sockets as conveyors

If none of the above work, you can also use network sockets locally *(unix sockets is a great way on nix systems). These are a bit more intricate and deserve their own post/answer. But editing to add it here as it's a good option to communicate between processes. Especially if they should run multiple tasks and return values.

Validate SSL certificates with Python

M2Crypto can do the validation. You can also use M2Crypto with Twisted if you like. The Chandler desktop client uses Twisted for networking and M2Crypto for SSL, including certificate validation.

Based on Glyphs comment it seems like M2Crypto does better certificate verification by default than what you can do with pyOpenSSL currently, because M2Crypto checks subjectAltName field too.

I've also blogged on how to get the certificates Mozilla Firefox ships with in Python and usable with Python SSL solutions.

How to install Google Play Services in a Genymotion VM (with no drag and drop support)?

I tried almost all of the above options, but was not able to install google play services, however just found from the faq section of genymotion that the only way to access google play services is to use the packages provided by OpenGapps.

I tried and this worked:

  1. Visit opengapps.org
  2. Select x86 as platform
  3. Choose the Android version corresponding to your virtual device
  4. Select nano as variant
  5. Download the zip file
  6. Drag & Drop the zip installer in new Genymotion virtual device (2.7.2 and above only)
  7. Follow the pop-up instructions

Chrome Extension - Get DOM content

For those who tried gkalpak answer and it did not work,

be aware that chrome will add the content script to a needed page only when your extension enabled during chrome launch and also a good idea restart browser after making these changes

Sending a JSON to server and retrieving a JSON in return, without JQuery

Sending and receiving data in JSON format using POST method

// Sending and receiving data in JSON format using POST method
//
var xhr = new XMLHttpRequest();
var url = "url";
xhr.open("POST", url, true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.onreadystatechange = function () {
    if (xhr.readyState === 4 && xhr.status === 200) {
        var json = JSON.parse(xhr.responseText);
        console.log(json.email + ", " + json.password);
    }
};
var data = JSON.stringify({"email": "[email protected]", "password": "101010"});
xhr.send(data);

Sending and receiving data in JSON format using GET method

// Sending a receiving data in JSON format using GET method
//      
var xhr = new XMLHttpRequest();
var url = "url?data=" + encodeURIComponent(JSON.stringify({"email": "[email protected]", "password": "101010"}));
xhr.open("GET", url, true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.onreadystatechange = function () {
    if (xhr.readyState === 4 && xhr.status === 200) {
        var json = JSON.parse(xhr.responseText);
        console.log(json.email + ", " + json.password);
    }
};
xhr.send();

Handling data in JSON format on the server-side using PHP

<?php
// Handling data in JSON format on the server-side using PHP
//
header("Content-Type: application/json");
// build a PHP variable from JSON sent using POST method
$v = json_decode(stripslashes(file_get_contents("php://input")));
// build a PHP variable from JSON sent using GET method
$v = json_decode(stripslashes($_GET["data"]));
// encode the PHP variable to JSON and send it back on client-side
echo json_encode($v);
?>

The limit of the length of an HTTP Get request is dependent on both the server and the client (browser) used, from 2kB - 8kB. The server should return 414 (Request-URI Too Long) status if an URI is longer than the server can handle.

Note Someone said that I could use state names instead of state values; in other words I could use xhr.readyState === xhr.DONE instead of xhr.readyState === 4 The problem is that Internet Explorer uses different state names so it's better to use state values.

semaphore implementation

The fundamental issue with your code is that you mix two APIs. Unfortunately online resources are not great at pointing this out, but there are two semaphore APIs on UNIX-like systems:

  • POSIX IPC API, which is a standard API
  • System V API, which is coming from the old Unix world, but practically available almost all Unix systems

Looking at the code above you used semget() from the System V API and tried to post through sem_post() which comes from the POSIX API. It is not possible to mix them.

To decide which semaphore API you want you don't have so many great resources. The simple best is the "Unix Network Programming" by Stevens. The section that you probably interested in is in Vol #2.

These two APIs are surprisingly different. Both support the textbook style semaphores but there are a few good and bad points in the System V API worth mentioning:

  • it builds on semaphore sets, so once you created an object with semget() that is a set of semaphores rather then a single one
  • the System V API allows you to do atomic operations on these sets. so you can modify or wait for multiple semaphores in a set
  • the SysV API allows you to wait for a semaphore to reach a threshold rather than only being non-zero. waiting for a non-zero threshold is also supported, but my previous sentence implies that
  • the semaphore resources are pretty limited on every unixes. you can check these with the 'ipcs' command
  • there is an undo feature of the System V semaphores, so you can make sure that abnormal program termination doesn't leave your semaphores in an undesired state

How do I list one filename per output line in Linux?

Use the -1 option (note this is a "one" digit, not a lowercase letter "L"), like this:

ls -1a

First, though, make sure your ls supports -1. GNU coreutils (installed on standard Linux systems) and Solaris do; but if in doubt, use man ls or ls --help or check the documentation. E.g.:

$ man ls
...
       -1     list one file per line.  Avoid '\n' with -q or -b

How can I add new array elements at the beginning of an array in Javascript?

array operations image

_x000D_
_x000D_
var a = [23, 45, 12, 67];_x000D_
a.unshift(34);_x000D_
console.log(a); // [34, 23, 45, 12, 67]
_x000D_
_x000D_
_x000D_

With arrays, why is it the case that a[5] == 5[a]?

A little bit of history now. Among other languages, BCPL had a fairly major influence on C's early development. If you declared an array in BCPL with something like:

let V = vec 10

that actually allocated 11 words of memory, not 10. Typically V was the first, and contained the address of the immediately following word. So unlike C, naming V went to that location and picked up the address of the zeroeth element of the array. Therefore array indirection in BCPL, expressed as

let J = V!5

really did have to do J = !(V + 5) (using BCPL syntax) since it was necessary to fetch V to get the base address of the array. Thus V!5 and 5!V were synonymous. As an anecdotal observation, WAFL (Warwick Functional Language) was written in BCPL, and to the best of my memory tended to use the latter syntax rather than the former for accessing the nodes used as data storage. Granted this is from somewhere between 35 and 40 years ago, so my memory is a little rusty. :)

The innovation of dispensing with the extra word of storage and having the compiler insert the base address of the array when it was named came later. According to the C history paper this happened at about the time structures were added to C.

Note that ! in BCPL was both a unary prefix operator and a binary infix operator, in both cases doing indirection. just that the binary form included an addition of the two operands before doing the indirection. Given the word oriented nature of BCPL (and B) this actually made a lot of sense. The restriction of "pointer and integer" was made necessary in C when it gained data types, and sizeof became a thing.

Using Predicate in Swift

// change "name" and "value" according to your array data.

// Change "yourDataArrayName" name accroding to your array(NSArray).

    let resultPredicate = NSPredicate(format: "SELF.name contains[c] %@", "value")

    if let sortedDta = yourDataArrayName.filtered(using: resultPredicate) as? NSArray {

 //enter code here.

        print(sortedDta)
    }

Cross-Domain Cookies

One can use invisible iframes to get the cookies. Let's say there are two domains, a.com and b.com. For the index.html of domain a.com one can add (notice height=0 width=0):

<iframe height="0" id="iframe" src="http://b.com" width="0"></iframe>

That way your website will get b.com cookies assuming that http://b.com sets the cookies.

The next thing would be manipulating the site inside the iframe through JavaScript. The operations inside iframe may become a challenge if one doesn't own the second domain. But in case of having access to both domains referring the right web page at the src of iframe should give the cookies one would like to get.

Center image horizontally within a div

This is what I ended up doing:

<div style="height: 600px">
   <img src="assets/zzzzz.png" alt="Error" style="max-width: 100%; 
        max-height: 100%; display:block; margin:auto;" />
</div>

Which will limit the image height to 600px and will horizontally-center (or resize down if the parent width is smaller) to the parent container, maintaining proportions.

Bootstrap 3 jquery event for active tab change

Thanks to @Gerben's post came to know there are two events show.bs.tab (before the tab is shown) and shown.bs.tab (after the tab is shown) as explained in the docs - Bootstrap Tab usage

An additional solution if we're only interested in a specific tab, and maybe add separate functions without having to add an if - else block in one function, is to use the a href selector (maybe along with additional selectors if required)

 $("a[href='#tab_target_id']").on('shown.bs.tab', function(e) {
      console.log('shown - after the tab has been shown');
 });

 // or even this one if we want the earlier event
 $("a[href='#tab_target_id']").on('show.bs.tab', function(e) {
      console.log('show - before the new tab has been shown');
 });

demo

Java; String replace (using regular expressions)?

private String removeScript(String content) {
    Pattern p = Pattern.compile("<script[^>]*>(.*?)</script>",
            Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
    return p.matcher(content).replaceAll("");
}

Disable sorting for a particular column in jQuery DataTables

columnDefs now accepts a class. I'd say this is the preferred method if you'd like to specify columns to disable in your markup:

<table>
    <thead>
        <tr>
            <th>ID</th>
            <th>Name</th>
            <th class="datatable-nosort">Actions</th>
        </tr>
    </thead>
    ...
</table>

Then, in your JS:

$("table").DataTable({
    columnDefs: [{
        targets: "datatable-nosort",
        orderable: false
    }]
});

What's the difference between .so, .la and .a library files?

.so files are dynamic libraries. The suffix stands for "shared object", because all the applications that are linked with the library use the same file, rather than making a copy in the resulting executable.

.a files are static libraries. The suffix stands for "archive", because they're actually just an archive (made with the ar command -- a predecessor of tar that's now just used for making libraries) of the original .o object files.

.la files are text files used by the GNU "libtools" package to describe the files that make up the corresponding library. You can find more information about them in this question: What are libtool's .la file for?

Static and dynamic libraries each have pros and cons.

Static pro: The user always uses the version of the library that you've tested with your application, so there shouldn't be any surprising compatibility problems.

Static con: If a problem is fixed in a library, you need to redistribute your application to take advantage of it. However, unless it's a library that users are likely to update on their own, you'd might need to do this anyway.

Dynamic pro: Your process's memory footprint is smaller, because the memory used for the library is amortized among all the processes using the library.

Dynamic pro: Libraries can be loaded on demand at run time; this is good for plugins, so you don't have to choose the plugins to be used when compiling and installing the software. New plugins can be added on the fly.

Dynamic con: The library might not exist on the system where someone is trying to install the application, or they might have a version that's not compatible with the application. To mitigate this, the application package might need to include a copy of the library, so it can install it if necessary. This is also often mitigated by package managers, which can download and install any necessary dependencies.

Dynamic con: Link-Time Optimization is generally not possible, so there could possibly be efficiency implications in high-performance applications. See the Wikipedia discussion of WPO and LTO.

Dynamic libraries are especially useful for system libraries, like libc. These libraries often need to include code that's dependent on the specific OS and version, because kernel interfaces have changed. If you link a program with a static system library, it will only run on the version of the OS that this library version was written for. But if you use a dynamic library, it will automatically pick up the library that's installed on the system you run on.

What is the difference between square brackets and parentheses in a regex?

These regexes are equivalent (for matching purposes):

  • /^(7|8|9)\d{9}$/
  • /^[789]\d{9}$/
  • /^[7-9]\d{9}$/

The explanation:

  • (a|b|c) is a regex "OR" and means "a or b or c", although the presence of brackets, necessary for the OR, also captures the digit. To be strictly equivalent, you would code (?:7|8|9) to make it a non capturing group.

  • [abc] is a "character class" that means "any character from a,b or c" (a character class may use ranges, e.g. [a-d] = [abcd])

The reason these regexes are similar is that a character class is a shorthand for an "or" (but only for single characters). In an alternation, you can also do something like (abc|def) which does not translate to a character class.

Post multipart request with Android SDK

Remove all your httpclient, httpmime dependency and add this dependency compile 'commons-httpclient:commons-httpclient:3.1'. This dependency has built in MultipartRequestEntity so that you can easily upload one or more files to the server

public class FileUploadUrlConnection extends AsyncTask<String, String, String> {
private Context context;
private String url;
private List<File> files;

public FileUploadUrlConnection(Context context, String url, List<File> files) {
    this.context = context;
    this.url = url;
    this.files = files;
}

@Override
protected String doInBackground(String... params) {

    HttpClient client = new HttpClient();
    PostMethod post = new PostMethod(url);
    HttpClientParams connectionParams = new HttpClientParams();

    post.setRequestHeader(// Your header goes here );

    try {
        Part[] parts = new Part[files.size()];
        for (int i=0; i<files.size(); i++) {
            Part part = new FilePart(files.get(i).getName(), files.get(i));
            parts[i] = part;
        }

        MultipartRequestEntity entity = new MultipartRequestEntity(parts, connectionParams);

        post.setRequestEntity(entity);

        int statusCode = client.executeMethod(post);
        String response = post.getResponseBodyAsString();

        Log.v("Multipart "," "+response);
        if(statusCode == 200) {
            return response;
        }
    } catch (IOException e) {
        e.printStackTrace();
    } 
 return null;
}

You can also add the request and response timeout

client.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 10000);
client.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, 10000);

MySQL INSERT INTO ... VALUES and SELECT

INSERT INTO table1 
SELECT "A string", 5, idTable2
FROM table2
WHERE ...

See: http://dev.mysql.com/doc/refman/5.6/en/insert-select.html

iptables LOG and DROP in one rule

nflog is better

sudo apt-get -y install ulogd2

ICMP Block rule example:

iptables=/sbin/iptables
# Drop ICMP (PING)
$iptables -t mangle -A PREROUTING -p icmp -j NFLOG --nflog-prefix 'ICMP Block'
$iptables -t mangle -A PREROUTING -p icmp -j DROP

And you can search prefix "ICMP Block" in log:

/var/log/ulog/syslogemu.log

How to get First and Last record from a sql query?

You might want to try this, could potentially be faster than doing two queries:

select <some columns>
from (
    SELECT <some columns>,
           row_number() over (order by date desc) as rn,
           count(*) over () as total_count
    FROM mytable
    <maybe some joins here>
    WHERE <various conditions>
) t
where rn = 1
   or rn = total_count
ORDER BY date DESC

Google Maps API v3 marker with label

In order to add a label to the map you need to create a custom overlay. The sample at http://blog.mridey.com/2009/09/label-overlay-example-for-google-maps.html uses a custom class, Layer, that inherits from OverlayView (which inherits from MVCObject) from the Google Maps API. He has a revised version (adds support for visibility, zIndex and a click event) which can be found here: http://blog.mridey.com/2011/05/label-overlay-example-for-google-maps.html

The following code is taken directly from Marc Ridey's Blog (the revised link above).

Layer class

// Define the overlay, derived from google.maps.OverlayView
function Label(opt_options) {
  // Initialization
  this.setValues(opt_options);


  // Label specific
  var span = this.span_ = document.createElement('span');
  span.style.cssText = 'position: relative; left: -50%; top: -8px; ' +
  'white-space: nowrap; border: 1px solid blue; ' +
  'padding: 2px; background-color: white';


  var div = this.div_ = document.createElement('div');
  div.appendChild(span);
  div.style.cssText = 'position: absolute; display: none';
};
Label.prototype = new google.maps.OverlayView;


// Implement onAdd
Label.prototype.onAdd = function() {
  var pane = this.getPanes().overlayImage;
  pane.appendChild(this.div_);


  // Ensures the label is redrawn if the text or position is changed.
  var me = this;
  this.listeners_ = [
    google.maps.event.addListener(this, 'position_changed', function() { me.draw(); }),
    google.maps.event.addListener(this, 'visible_changed', function() { me.draw(); }),
    google.maps.event.addListener(this, 'clickable_changed', function() { me.draw(); }),
    google.maps.event.addListener(this, 'text_changed', function() { me.draw(); }),
    google.maps.event.addListener(this, 'zindex_changed', function() { me.draw(); }),
    google.maps.event.addDomListener(this.div_, 'click', function() {
      if (me.get('clickable')) {
        google.maps.event.trigger(me, 'click');
      }
    })
  ];
};

// Implement onRemove
Label.prototype.onRemove = function() {
 this.div_.parentNode.removeChild(this.div_);

 // Label is removed from the map, stop updating its position/text.
 for (var i = 0, I = this.listeners_.length; i < I; ++i) {
   google.maps.event.removeListener(this.listeners_[i]);
 }
};

// Implement draw
Label.prototype.draw = function() {
 var projection = this.getProjection();
 var position = projection.fromLatLngToDivPixel(this.get('position'));

 var div = this.div_;
 div.style.left = position.x + 'px';
 div.style.top = position.y + 'px';
 div.style.display = 'block';

 this.span_.innerHTML = this.get('text').toString();
};

Usage

<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8">
    <title>
      Label Overlay Example
    </title>
    <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
    <script type="text/javascript" src="label.js"></script>
    <script type="text/javascript">
      var marker;


      function initialize() {
        var latLng = new google.maps.LatLng(40, -100);


        var map = new google.maps.Map(document.getElementById('map_canvas'), {
          zoom: 5,
          center: latLng,
          mapTypeId: google.maps.MapTypeId.ROADMAP
        });


        marker = new google.maps.Marker({
          position: latLng,
          draggable: true,
          zIndex: 1,
          map: map,
          optimized: false
        });


        var label = new Label({
          map: map
        });
        label.bindTo('position', marker);
        label.bindTo('text', marker, 'position');
        label.bindTo('visible', marker);
        label.bindTo('clickable', marker);
        label.bindTo('zIndex', marker);


        google.maps.event.addListener(marker, 'click', function() { alert('Marker has been clicked'); })
        google.maps.event.addListener(label, 'click', function() { alert('Label has been clicked'); })
      }


      function showHideMarker() {
        marker.setVisible(!marker.getVisible());
      }


      function pinUnpinMarker() {
        var draggable = marker.getDraggable();
        marker.setDraggable(!draggable);
        marker.setClickable(!draggable);
      }
    </script>
  </head>
  <body onload="initialize()">
    <div id="map_canvas" style="height: 200px; width: 200px"></div>
    <button type="button" onclick="showHideMarker();">Show/Hide Marker</button>
    <button type="button" onclick="pinUnpinMarker();">Pin/Unpin Marker</button>
  </body>
</html>

When should you use 'friend' in C++?

In C++ "friend" keyword is useful in Operator overloading and Making Bridge.

1.) Friend keyword in operator overloading :
Example for operator overloading is: Let say we have a class "Point" that has two float variable
"x"(for x-coordinate) and "y"(for y-coordinate). Now we have to overload "<<"(extraction operator) such that if we call "cout << pointobj" then it will print x and y coordinate (where pointobj is an object of class Point). To do this we have two option:

   1.Overload "operator <<()" function in "ostream" class.
   2.Overload "operator<<()" function in "Point" class.
Now First option is not good because if we need to overload again this operator for some different class then we have to again make change in "ostream" class.
That's why second is best option. Now compiler can call "operator <<()" function:

   1.Using ostream object cout.As: cout.operator<<(Pointobj) (form ostream class).
2.Call without an object.As: operator<<(cout, Pointobj) (from Point class).

Beacause we have implemented overloading in Point class. So to call this function without an object we have to add"friend" keyword because we can call a friend function without an object. Now function declaration will be As:
"friend ostream &operator<<(ostream &cout, Point &pointobj);"

2.) Friend keyword in making bridge :
Suppose we have to make a function in which we have to access private member of two or more classes ( generally termed as "bridge" ) . How to do this:
To access private member of a class it should be member of that class. Now to access private member of other class every class should declare that function as a friend function. For example : Suppose there are two class A and B. A function "funcBridge()" want to access private member of both classes. Then both class should declare "funcBridge()" as:
friend return_type funcBridge(A &a_obj, B & b_obj);

I think this would help to understand friend keyword.

How to perform keystroke inside powershell?

Also the $wshell = New-Object -ComObject wscript.shell; helped a script that was running in the background, it worked fine with just but adding $wshell. fixed it from running as background! [Microsoft.VisualBasic.Interaction]::AppActivate("App Name")

How do I move a table into a schema in T-SQL

Short answer:

ALTER SCHEMA new_schema TRANSFER old_schema.table_name

I can confirm that the data in the table remains intact, which is probably quite important :)

Long answer as per MSDN docs,

ALTER SCHEMA schema_name 
   TRANSFER [ Object | Type | XML Schema Collection ] securable_name [;]

If it's a table (or anything besides a Type or XML Schema collection), you can leave out the word Object since that's the default.

java: use StringBuilder to insert at the beginning

Difference Between String, StringBuilder And StringBuffer Classes
String
String is immutable ( once created can not be changed )object. The object created as a
String is stored in the Constant String Pool.
Every immutable object in Java is thread-safe, which implies String is also thread-safe. String
can not be used by two threads simultaneously.
String once assigned can not be changed.
StringBuffer
StringBuffer is mutable means one can change the value of the object. The object created
through StringBuffer is stored in the heap. StringBuffer has the same methods as the
StringBuilder , but each method in StringBuffer is synchronized that is StringBuffer is thread
safe .
Due to this, it does not allow two threads to simultaneously access the same method. Each
method can be accessed by one thread at a time.
But being thread-safe has disadvantages too as the performance of the StringBuffer hits due
to thread-safe property. Thus StringBuilder is faster than the StringBuffer when calling the
same methods of each class.
String Buffer can be converted to the string by using
toString() method.

    StringBuffer demo1 = new StringBuffer("Hello") ;

// The above object stored in heap and its value can be changed.
/
// Above statement is right as it modifies the value which is allowed in the StringBuffer
StringBuilder
StringBuilder is the same as the StringBuffer, that is it stores the object in heap and it can also
be modified. The main difference between the StringBuffer and StringBuilder is
that StringBuilder is also not thread-safe.
StringBuilder is fast as it is not thread-safe.
/
// The above object is stored in the heap and its value can be modified
/
// Above statement is right as it modifies the value which is allowed in the StringBuilder

MySQL: View with Subquery in the FROM Clause Limitation

You can work around this by creating a separate VIEW for any subquery you want to use and then join to that in the VIEW you're creating. Here's an example: http://blog.gruffdavies.com/2015/01/25/a-neat-mysql-hack-to-create-a-view-with-subquery-in-the-from-clause/

This is quite handy as you'll very likely want to reuse it anyway and helps you keep your SQL DRY.

using javascript to detect whether the url exists before display in iframe

I created this method, it is ideal because it aborts the connection without downloading it in its entirety, ideal for checking if videos or large images exist, decreasing the response time and the need to download the entire file

// if-url-exist.js v1
function ifUrlExist(url, callback) {
    let request = new XMLHttpRequest;
    request.open('GET', url, true);
    request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    request.setRequestHeader('Accept', '*/*');
    request.onprogress = function(event) {
        let status = event.target.status;
        let statusFirstNumber = (status).toString()[0];
        switch (statusFirstNumber) {
            case '2':
                request.abort();
                return callback(true);
            default:
                request.abort();
                return callback(false);
        };
    };
    request.send('');
};

Example of use:

ifUrlExist(url, function(exists) {
    console.log(exists);
});

After installing with pip, "jupyter: command not found"

If you installed Jupyter notebook for Python 2 using 'pip' instead of 'pip3' it might work to run:

ipython notebook

How to give a delay in loop execution using Qt

EDIT (removed wrong solution). EDIT (to add this other option):

Another way to use it would be subclass QThread since it has protected *sleep methods.

QThread::usleep(unsigned long microseconds);
QThread::msleep(unsigned long milliseconds);
QThread::sleep(unsigned long second);

Here's the code to create your own *sleep method.

#include <QThread>    

class Sleeper : public QThread
{
public:
    static void usleep(unsigned long usecs){QThread::usleep(usecs);}
    static void msleep(unsigned long msecs){QThread::msleep(msecs);}
    static void sleep(unsigned long secs){QThread::sleep(secs);}
};

and you call it by doing this:

Sleeper::usleep(10);
Sleeper::msleep(10);
Sleeper::sleep(10);

This would give you a delay of 10 microseconds, 10 milliseconds or 10 seconds, accordingly. If the underlying operating system timers support the resolution.

How to beautify JSON in Python?

Use the indent argument of the dumps function in the json module.

From the docs:

>>> import json
>>> print json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)
{
    "4": 5,
    "6": 7
}

How to use tick / checkmark symbol (?) instead of bullets in unordered list?

Here are three different checkmark styles you can use:

_x000D_
_x000D_
ul:first-child  li:before { content:"\2713\0020"; }  /* OR */_x000D_
ul:nth-child(2) li:before { content:"\2714\0020"; }  /* OR */_x000D_
ul:last-child   li:before { content:"\2611\0020"; }_x000D_
ul { list-style-type: none; }
_x000D_
<ul>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
</ul>_x000D_
_x000D_
<ul>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
</ul>_x000D_
_x000D_
<ul><!-- not working on Stack snippet; check fiddle demo -->_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
  <li>this is my text</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

jsFiddle

References:

Show div when radio button selected

I would handle it like so:

$(document).ready(function() {
   $('input[type="radio"]').click(function() {
       if($(this).attr('id') == 'watch-me') {
            $('#show-me').show();           
       }

       else {
            $('#show-me').hide();   
       }
   });
});

Change Twitter Bootstrap Tooltip content on click

if you have set the title attribute in HTML then use on click of the icon or button $(this).attr('title',newValue);

"Access is denied" JavaScript error when trying to access the document object of a programmatically-created <iframe> (IE-only)

Well yes, the access exception is due to the fact that document.domain must match in your parent and your iframe, and before they do, you won't be able to programmatically set the document.domain property of your iframe.

I think your best option here is to point the page to a template of your own:

iframe.src = '/myiframe.htm#' + document.domain;

And in myiframe.htm:

document.domain = location.hash.substring(1);

sklearn error ValueError: Input contains NaN, infinity or a value too large for dtype('float64')

dataset = dataset.dropna(axis=0, how='any', thresh=None, subset=None, inplace=False)

This worked for me

How to find the type of an object in Go?

To be short, please use fmt.Printf("%T", var1) or its other variants in the fmt package.

What is the Ruby <=> (spaceship) operator?

What is <=> ( The 'Spaceship' Operator )

According to the RFC that introduced the operator, $a <=> $b

 -  0 if $a == $b
 - -1 if $a < $b
 -  1 if $a > $b

 - Return 0 if values on either side are equal
 - Return 1 if value on the left is greater
 - Return -1 if the value on the right is greater

Example:

//Comparing Integers

echo 1 <=> 1; //ouputs 0
echo 3 <=> 4; //outputs -1
echo 4 <=> 3; //outputs 1

//String Comparison

echo "x" <=> "x"; // 0
echo "x" <=> "y"; //-1
echo "y" <=> "x"; //1

MORE:

// Integers
echo 1 <=> 1; // 0
echo 1 <=> 2; // -1
echo 2 <=> 1; // 1

// Floats
echo 1.5 <=> 1.5; // 0
echo 1.5 <=> 2.5; // -1
echo 2.5 <=> 1.5; // 1

// Strings
echo "a" <=> "a"; // 0
echo "a" <=> "b"; // -1
echo "b" <=> "a"; // 1

echo "a" <=> "aa"; // -1
echo "zz" <=> "aa"; // 1

// Arrays
echo [] <=> []; // 0
echo [1, 2, 3] <=> [1, 2, 3]; // 0
echo [1, 2, 3] <=> []; // 1
echo [1, 2, 3] <=> [1, 2, 1]; // 1
echo [1, 2, 3] <=> [1, 2, 4]; // -1

// Objects
$a = (object) ["a" => "b"]; 
$b = (object) ["a" => "b"]; 
echo $a <=> $b; // 0

How do I print out the contents of a vector?

Using std::copy but without extra trailing separator

An alternative/modified approach using std::copy (as originally used in @JoshuaKravtiz answer) but without including an additional trailing separator after the last element:

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>

template <typename T>
void print_contents(const std::vector<T>& v, const char * const separator = " ")
{
    if(!v.empty())
    {
        std::copy(v.begin(),
                  --v.end(),
                  std::ostream_iterator<T>(std::cout, separator));
        std::cout << v.back() << "\n";
    }
}

// example usage
int main() {
    std::vector<int> v{1, 2, 3, 4};
    print_contents(v);      // '1 2 3 4'
    print_contents(v, ":"); // '1:2:3:4'
    v = {};
    print_contents(v);      // ... no std::cout
    v = {1};
    print_contents(v);      // '1'
    return 0;
}

Example usage applied to container of a custom POD type:

// includes and 'print_contents(...)' as above ...

class Foo
{
    int i;
    friend std::ostream& operator<<(std::ostream& out, const Foo& obj);
public:
    Foo(const int i) : i(i) {}
};

std::ostream& operator<<(std::ostream& out, const Foo& obj)
{
    return out << "foo_" << obj.i; 
}

int main() {
    std::vector<Foo> v{1, 2, 3, 4};
    print_contents(v);      // 'foo_1 foo_2 foo_3 foo_4'
    print_contents(v, ":"); // 'foo_1:foo_2:foo_3:foo_4'
    v = {};
    print_contents(v);      // ... no std::cout
    v = {1};
    print_contents(v);      // 'foo_1'
    return 0;
}

Force to open "Save As..." popup open at text link click for PDF in HTML

Meta tags are not a reliable way to achieve this result. Generally you shouldn't even do this - it should be left up to the user/user agent to decide what do to with the content you provide. The user can always force their browser to download the file if they wish to.

If you still want to force the browser to download the file, modify the HTTP headers directly. Here's a PHP code example:

$path = "path/to/file.pdf";
$filename = "file.pdf";
header('Content-Transfer-Encoding: binary');  // For Gecko browsers mainly
header('Last-Modified: ' . gmdate('D, d M Y H:i:s', filemtime($path)) . ' GMT');
header('Accept-Ranges: bytes');  // Allow support for download resume
header('Content-Length: ' . filesize($path));  // File size
header('Content-Encoding: none');
header('Content-Type: application/pdf');  // Change the mime type if the file is not PDF
header('Content-Disposition: attachment; filename=' . $filename);  // Make the browser display the Save As dialog
readfile($path);  // This is necessary in order to get it to actually download the file, otherwise it will be 0Kb

Note that this is just an extension to the HTTP protocol; some browsers might ignore it anyway.

Remove a file from the list that will be committed

Most of these answers circulate around removing a file from the "staging area" pre-commit, but I often find myself looking here after I've already committed and I want to remove some sensitive information from the commit I just made.

An easy to remember trick for all of you git commit --amend folks out there like me is that you can:

  1. Delete the accidentally committed file.
  2. git add . to add the deletion to the "staging area"
  3. git commit --amend to remove the file from the previous commit.

You will notice in the commit message that the unwanted file is now missing. Hooray! (Commit SHA will have changed, so be careful if you already pushed your changes to the remote.)

How can one grab a stack trace in C?

You should be using the unwind library.

unw_cursor_t cursor; unw_context_t uc;
unw_word_t ip, sp;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
unsigned long a[100];
int ctr = 0;

while (unw_step(&cursor) > 0) {
  unw_get_reg(&cursor, UNW_REG_IP, &ip);
  unw_get_reg(&cursor, UNW_REG_SP, &sp);
  if (ctr >= 10) break;
  a[ctr++] = ip;
}

Your approach also would work fine unless you make a call from a shared library.

You can use the addr2line command on Linux to get the source function / line number of the corresponding PC.

Convert Uri to String and String to Uri

Try this to convert string to uri

String mystring="Hello"
Uri myUri = Uri.parse(mystring);

Uri to String

Uri uri;
String uri_to_string;
uri_to_string= uri.toString();

SmtpException: Unable to read data from the transport connection: net_io_connectionclosed

For anyone who stumbles across this post looking for a solution and you've set up SMTP sendgrid via Azure.

The username is not the username you set up when you've created the sendgrid object in azure. To find your username;

  • Click on your sendgrid object in azure and click manage. You will be redirected to the SendGrid site.
  • Confirm your email and then copy down the username displayed there.. it's an automatically generated username.
  • Add the username from SendGrid into your SMTP settings in the web.config file.

Hope this helps!

How do you do relative time in Rails?

You can use the arithmetic operators to do relative time.

Time.now - 2.days 

Will give you 2 days ago.

How to [recursively] Zip a directory in PHP?

Here Is my code For Zip the folders and its sub folders and its files and make it downloadable in zip Format

function zip()
 {
$source='path/folder'// Path To the folder;
$destination='path/folder/abc.zip'// Path to the file and file name ; 
$include_dir = false;
$archive = 'abc.zip'// File Name ;

if (!extension_loaded('zip') || !file_exists($source)) {
    return false;
}

if (file_exists($destination)) {
    unlink ($destination);
}

$zip = new ZipArchive;

if (!$zip->open($archive, ZipArchive::CREATE)) {
    return false;
}
$source = str_replace('\\', '/', realpath($source));
if (is_dir($source) === true)
{

    $files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($source), RecursiveIteratorIterator::SELF_FIRST);

    if ($include_dir) {

        $arr = explode("/",$source);
        $maindir = $arr[count($arr)- 1];

        $source = "";
        for ($i=0; $i < count($arr) - 1; $i++) { 
            $source .= '/' . $arr[$i];
        }

        $source = substr($source, 1);

        $zip->addEmptyDir($maindir);

    }

    foreach ($files as $file)
    {
        $file = str_replace('\\', '/', $file);

        // Ignore "." and ".." folders
        if( in_array(substr($file, strrpos($file, '/')+1), array('.', '..')) )
            continue;

        $file = realpath($file);

        if (is_dir($file) === true)
        {
            $zip->addEmptyDir(str_replace($source . '/', '', $file . '/'));
        }
        else if (is_file($file) === true)
        {
            $zip->addFromString(str_replace($source . '/', '', $file), file_get_contents($file));
        }
    }
}
else if (is_file($source) === true)
{
    $zip->addFromString(basename($source), file_get_contents($source));
}
$zip->close();

header('Content-Type: application/zip');
header('Content-disposition: attachment; filename='.$archive);
header('Content-Length: '.filesize($archive));
readfile($archive);
unlink($archive);
}

If Any Issue With the Code Let Me know.

How do I add a custom script to my package.json file that runs a javascript file?

Suppose I have this line of scripts in my "package.json"

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "export_advertisements": "node export.js advertisements",
    "export_homedata": "node export.js homedata",
    "export_customdata": "node export.js customdata",
    "export_rooms": "node export.js rooms"
  },

Now to run the script "export_advertisements", I will simply go to the terminal and type

npm run export_advertisements

You are most welcome

Using android.support.v7.widget.CardView in my project (Eclipse)

I was able to work it out only after adding those two TOGETHER:

dependencies {
...
implementation 'com.android.support:recyclerview-v7:27.1.1'
implementation 'com.android.support:cardview-v7:27.1.1'
...
}

in my build.gradle (Module:app) file

and then press the sync now button

Change size of axes title and labels in ggplot2

To change the size of (almost) all text elements, in one place, and synchronously, rel() is quite efficient:
g+theme(text = element_text(size=rel(3.5))

You might want to tweak the number a bit, to get the optimum result. It sets both the horizontal and vertical axis labels and titles, and other text elements, on the same scale. One exception is faceted grids' titles which must be manually set to the same value, for example if both x and y facets are used in a graph:
theme(text = element_text(size=rel(3.5)), strip.text.x = element_text(size=rel(3.5)), strip.text.y = element_text(size=rel(3.5)))

CSS 3 slide-in from left transition

You can use CSS3 transitions or maybe CSS3 animations to slide in an element.

For browser support: http://caniuse.com/

I made two quick examples just to show you how I mean.

CSS transition (on hover)

Demo One

Relevant Code

.wrapper:hover #slide {
    transition: 1s;
    left: 0;
}

In this case, Im just transitioning the position from left: -100px; to 0; with a 1s. duration. It's also possible to move the element using transform: translate();

CSS animation

Demo Two

#slide {
    position: absolute;
    left: -100px;
    width: 100px;
    height: 100px;
    background: blue;
    -webkit-animation: slide 0.5s forwards;
    -webkit-animation-delay: 2s;
    animation: slide 0.5s forwards;
    animation-delay: 2s;
}

@-webkit-keyframes slide {
    100% { left: 0; }
}

@keyframes slide {
    100% { left: 0; }
}

Same principle as above (Demo One), but the animation starts automatically after 2s, and in this case I've set animation-fill-mode to forwards, which will persist the end state, keeping the div visible when the animation ends.

Like I said, two quick example to show you how it could be done.

EDIT: For details regarding CSS Animations and Transitions see:

Animations

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

Transitions

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

Hope this helped.

How to correctly get image from 'Resources' folder in NetBeans

I have a slightly different approach that might be useful/more beneficial to some.

Under your main project folder, create a resource folder. Your folder structure should look something like this.

  • Project Folder
    • build
    • dist
    • lib
    • nbproject
    • resources
    • src

Go to the properties of your project. You can do this by right clicking on your project in the Projects tab window and selecting Properties in the drop down menu.

Under categories on the left side, select Sources.

In Source Package Folders on the right side, add your resource folder using the Add Folder button. Once you click OK, you should see a Resources folder under your project.

enter image description here

You should now be able to pull resources using this line or similar approach:

MyClass.class.getResource("/main.jpg");

If you were to create a package called Images under the resources folder, you can retrieve the resource like this:

MyClass.class.getResource("/Images/main.jpg");

Shorthand if/else statement Javascript

Here is a way to do it that works, but may not be best practise for any language really:

var x,y;
x='something';
y=1;
undefined === y || (x = y);

alternatively

undefined !== y && (x = y);

OS X cp command in Terminal - No such file or directory

On OS X Sierra 10.12, None of the above work. cd then drag and drop does not work. No spacing or other fixes work. I cannot cd into ~/Library Support using any technique that I can find. Is this a security feature?
I'm going to try disabling SIP and see if it makes a difference.

Pandas: rolling mean by time interval

I just had the same question but with irregularly spaced datapoints. Resample is not really an option here. So I created my own function. Maybe it will be useful for others too:

from pandas import Series, DataFrame
import pandas as pd
from datetime import datetime, timedelta
import numpy as np

def rolling_mean(data, window, min_periods=1, center=False):
    ''' Function that computes a rolling mean

    Parameters
    ----------
    data : DataFrame or Series
           If a DataFrame is passed, the rolling_mean is computed for all columns.
    window : int or string
             If int is passed, window is the number of observations used for calculating 
             the statistic, as defined by the function pd.rolling_mean()
             If a string is passed, it must be a frequency string, e.g. '90S'. This is
             internally converted into a DateOffset object, representing the window size.
    min_periods : int
                  Minimum number of observations in window required to have a value.

    Returns
    -------
    Series or DataFrame, if more than one column    
    '''
    def f(x):
        '''Function to apply that actually computes the rolling mean'''
        if center == False:
            dslice = col[x-pd.datetools.to_offset(window).delta+timedelta(0,0,1):x]
                # adding a microsecond because when slicing with labels start and endpoint
                # are inclusive
        else:
            dslice = col[x-pd.datetools.to_offset(window).delta/2+timedelta(0,0,1):
                         x+pd.datetools.to_offset(window).delta/2]
        if dslice.size < min_periods:
            return np.nan
        else:
            return dslice.mean()

    data = DataFrame(data.copy())
    dfout = DataFrame()
    if isinstance(window, int):
        dfout = pd.rolling_mean(data, window, min_periods=min_periods, center=center)
    elif isinstance(window, basestring):
        idx = Series(data.index.to_pydatetime(), index=data.index)
        for colname, col in data.iterkv():
            result = idx.apply(f)
            result.name = colname
            dfout = dfout.join(result, how='outer')
    if dfout.columns.size == 1:
        dfout = dfout.ix[:,0]
    return dfout


# Example
idx = [datetime(2011, 2, 7, 0, 0),
       datetime(2011, 2, 7, 0, 1),
       datetime(2011, 2, 7, 0, 1, 30),
       datetime(2011, 2, 7, 0, 2),
       datetime(2011, 2, 7, 0, 4),
       datetime(2011, 2, 7, 0, 5),
       datetime(2011, 2, 7, 0, 5, 10),
       datetime(2011, 2, 7, 0, 6),
       datetime(2011, 2, 7, 0, 8),
       datetime(2011, 2, 7, 0, 9)]
idx = pd.Index(idx)
vals = np.arange(len(idx)).astype(float)
s = Series(vals, index=idx)
rm = rolling_mean(s, window='2min')

Jquery set radio button checked, using id and class selectors

"...by a class and a div."

I assume when you say "div" you mean "id"? Try this:

$('#test2.test1').prop('checked', true);

No need to muck about with your [attributename=value] style selectors because id has its own format as does class, and they're easily combined although given that id is supposed to be unique it should be enough on its own unless your meaning is "select that element only if it currently has the specified class".

Or more generally to select an input where you want to specify a multiple attribute selector:

$('input:radio[class=test1][id=test2]').prop('checked', true);

That is, list each attribute with its own square brackets.

Note that unless you have a pretty old version of jQuery you should use .prop() rather than .attr() for this purpose.

Python Binomial Coefficient

For everyone looking for the log of the binomial coefficient (Theano calls this binomln), this answer has it:

from numpy import log
from scipy.special import betaln

def binomln(n, k):
    "Log of scipy.special.binom calculated entirely in the log domain"
    return -betaln(1 + n - k, 1 + k) - log(n + 1)

(And if your language/library lacks betaln but has gammaln, like Go, have no fear, since betaln(a, b) is just gammaln(a) + gammaln(b) - gammaln(a + b), per MathWorld.)

How to check Elasticsearch cluster health?

The _cluster/health API can do far more than the typical output that most see with it:

 $ curl -XGET 'localhost:9200/_cluster/health?pretty'

Most APIs within Elasticsearch can take a variety of arguments to augment their output. This applies to Cluster Health API as well.

Examples

all the indices health
$ curl -XGET 'localhost:9200/_cluster/health?level=indices&pretty' | head -50
{
  "cluster_name" : "rdu-es-01",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 9,
  "number_of_data_nodes" : 6,
  "active_primary_shards" : 1106,
  "active_shards" : 2213,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0,
  "indices" : {
    "filebeat-6.5.1-2019.06.10" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    },
    "filebeat-6.5.1-2019.06.11" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    },
    "filebeat-6.5.1-2019.06.12" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0
    },
    "filebeat-6.5.1-2019.06.13" : {
      "status" : "green",
      "number_of_shards" : 3,
all shards health
$ curl -XGET 'localhost:9200/_cluster/health?level=shards&pretty' | head -50
{
  "cluster_name" : "rdu-es-01",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 9,
  "number_of_data_nodes" : 6,
  "active_primary_shards" : 1106,
  "active_shards" : 2213,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0,
  "indices" : {
    "filebeat-6.5.1-2019.06.10" : {
      "status" : "green",
      "number_of_shards" : 3,
      "number_of_replicas" : 1,
      "active_primary_shards" : 3,
      "active_shards" : 6,
      "relocating_shards" : 0,
      "initializing_shards" : 0,
      "unassigned_shards" : 0,
      "shards" : {
        "0" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0
        },
        "1" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0
        },
        "2" : {
          "status" : "green",
          "primary_active" : true,
          "active_shards" : 2,
          "relocating_shards" : 0,
          "initializing_shards" : 0,
          "unassigned_shards" : 0

The API also has a variety of wait_* options where it'll wait for various state changes before returning immediately or after some specified timeout.

Converting std::__cxx11::string to std::string

Answers here mostly focus on short way to fix it, but if that does not help, I'll give some steps to check, that helped me (Linux only):

  • If the linker errors happen when linking other libraries, build those libs with debug symbols ("-g" GCC flag)
  • List the symbols in the library and grep the symbols that linker complains about (enter the commands in command line):

    nm lib_your_problem_library.a | grep functionNameLinkerComplainsAbout

  • If you got the method signature, proceed to the next step, if you got no symbols instead, mostlikely you stripped off all the symbols from the library and that is why linker can't find them when linking the library. Rebuild the library without stripping ALL the symbols, you can strip debug (strip -S option) symbols if you need.

  • Use a c++ demangler to understand the method signature, for example, this one

  • Compare the method signature in the library that you just got with the one you are using in code (check header file as well), if they are different, use the proper header or the proper library or whatever other way you now know to fix it

Python/Json:Expecting property name enclosed in double quotes

For anyone who wants a quick-fix, this simply replaces all single quotes with double quotes:

import json 

predictions = []

def get_top_k_predictions(predictions_path):
    '''load the predictions'''
    
    with open (predictions_path) as json_lines_file:
        for line in json_lines_file:
            predictions.append(json.loads(line.replace("'", "\"")))
            
    
get_top_k_predictions("/sh/sh-experiments/outputs/john/baseline_1000/test_predictions.jsonl")

Copying a rsa public key to clipboard

Window:

cat ~/.ssh/id_rsa.pub

Mac OS:

cat ~/.ssh/id_rsa.pub | pbcopy

Best way to get value from Collection by index

use for each loop...

ArrayList<Character> al = new ArrayList<>();    
String input="hello";

for (int i = 0; i < input.length(); i++){
    al.add(input.charAt(i));
}

for (Character ch : al) {               
    System.Out.println(ch);             
}

How to select option in drop down using Capybara

Unfortunately, the most popular answer did not work for me entirely. I had to add .select_option to end of the statement

select("option_name_here", from: "organizationSelect").select_option

without the select_option, no select was being performed

How do you store Java objects in HttpSession?

Add it to the session, not to the request.

HttpSession session = request.getSession();
session.setAttribute("object", object);

Also, don't use scriptlets in the JSP. Use EL instead; to access object all you need is ${object}.

A primary feature of JSP technology version 2.0 is its support for an expression language (EL). An expression language makes it possible to easily access application data stored in JavaBeans components. For example, the JSP expression language allows a page author to access a bean using simple syntax such as ${name} for a simple variable or ${name.foo.bar} for a nested property.

how do I check in bash whether a file was created more than x time ago?

The find one is good but I think you can use anotherway, especially if you need to now how many seconds is the file old

date -d "now - $( stat -c "%Y" $filename ) seconds" +%s

using GNU date

What does "javax.naming.NoInitialContextException" mean?

In extremely non-technical terms, it may mean that you forgot to put "ejb:" or "jdbc:" or something at the very beginning of the URI you are trying to connect.

WCF Service Returning "Method Not Allowed"

you need to add in web.config

<endpoint address="customBinding" binding="customBinding" bindingConfiguration="basicConfig" contract="WcfRest.IService1"/>  

<bindings>  
    <customBinding>  
        <binding name="basicConfig">  
            <binaryMessageEncoding/>  
            <httpTransport transferMode="Streamed" maxReceivedMessageSize="67108864"/>  
        </binding>  
    </customBinding> 

Get the last day of the month in SQL

I wrote following function, it works.

It returns datetime data type. Zero hour, minute, second, miliseconds.

CREATE Function [dbo].[fn_GetLastDate]
(
    @date datetime
)
returns datetime
as
begin

declare @result datetime

 select @result = CHOOSE(month(@date),  
 DATEADD(DAY, 31 -day(@date), @date),
 IIF(YEAR(@date) % 4 = 0, DATEADD(DAY, 29 -day(@date), @date), DATEADD(DAY, 28 -day(@date), @date)), 
 DATEADD(DAY, 31 -day(@date), @date) ,
 DATEADD(DAY, 30 -day(@date), @date), 
 DATEADD(DAY, 31 -day(@date), @date),
 DATEADD(DAY, 30 -day(@date), @date), 
 DATEADD(DAY, 31 -day(@date), @date),
 DATEADD(DAY, 31 -day(@date), @date),
 DATEADD(DAY, 30 -day(@date), @date),
 DATEADD(DAY, 31 -day(@date), @date),
 DATEADD(DAY, 30 -day(@date), @date), 
 DATEADD(DAY, 31 -day(@date), @date))

 return convert(date, @result)

end

It's very easy to use. 2 example:

select [dbo].[fn_GetLastDate]('2016-02-03 12:34:12')

select [dbo].[fn_GetLastDate](GETDATE())

Determine when a ViewPager changes pages

For ViewPager2,

viewPager.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
  override fun onPageSelected(position: Int) {
    super.onPageSelected(position)
  }
})

where OnPageChangeCallback is a static class with three methods:

onPageScrolled(int position, float positionOffset, @Px int positionOffsetPixels),
onPageSelected(int position), 
onPageScrollStateChanged(@ScrollState int state)

PHP json_decode() returns NULL with valid JSON?

Here you can find little JSON wrapper with corrective actions that addresses BOM and non-ASCI issue: https://stackoverflow.com/a/43694325/2254935

Swapping two variable value without using third variable

Here is one more solution but a single risk.

code:

#include <iostream>
#include <conio.h>
void main()
{

int a =10 , b =45;
*(&a+1 ) = a;
a =b;
b =*(&a +1);
}

any value at location a+1 will be overridden.

LDAP: error code 49 - 80090308: LdapErr: DSID-0C0903A9, comment: AcceptSecurityContext error, data 52e, v1db1

For me the issue resolved when I set the principal section like this:

env.put(Context.SECURITY_PRINCIPAL, userId@domainWithoutProtocolAndPortNo);

How to save password when using Subversion from the console

Using plaintext may not be the best choice, if the password is ever used as something else.

I support the accepted answer, but it didn't work for me - for a very specific reason: I wanted to use either kwallet or gnome-keyring password stores. I tried changing the settings, all over the four files:

/etc/subversion/config
/etc/subversion/servers
~/.subversion/config
~/.subversion/servers

Even after it all was set the same, with password-stores and KWallet name (default might be wrong, right?) it didn't work and kept asking for password forever. The files in ~/.subversion had permissions 600.

Well, at that point, you may try to check one simple thing:

which svn

If you get:

/usr/bin/local/svn

then you may suspect with great likelihood that this client was built from source, locally, by your administrator (which may be yourself, as in my case).

Subversion is a nasty beast to compile, very easy to accidentally build without HTTP support, or - as in my example - without support for encrypted password stores (you need either Gnome or KDE development files, and a lot of them!). But the ./configure script won't tell you that, and you just get a less functional svn command.

In that case, you may go back to the client, which came with your distribution, usually in /usr/bin/svn. The downside is - you'll probably need to re-checkout the working copies, as there is no svn downgrade command. You can consult Linus Torvalds on what to think about Subversion, anyway ;)

write() versus writelines() and concatenated strings

Actually, I think the problem is that your variable "lines" is bad. You defined lines as a tuple, but I believe that write() requires a string. All you have to change is your commas into pluses (+).

nl = "\n"
lines = line1+nl+line2+nl+line3+nl
textdoc.writelines(lines)

should work.

this in equals method

You are comparing two objects for equality. The snippet:

if (obj == this) {     return true; } 

is a quick test that can be read

"If the object I'm comparing myself to is me, return true"

. You usually see this happen in equals methods so they can exit early and avoid other costly comparisons.

Stretch Image to Fit 100% of Div Height and Width

will the height attribute stretch the image beyond its native resolution? If I have a image with a height of say 420 pixels, I can't get css to stretch the image beyond the native resolution to fill the height of the viewport.

I am getting pretty close results with:

 .rightdiv img {
        max-width: 25vw;
        min-height: 100vh;
    }

the 100vh is getting pretty close, with just a few pixels left over at the bottom for some reason.

Find column whose name contains a specific string

# select columns containing 'spike'
df.filter(like='spike', axis=1)

You can also select by name, regular expression. Refer to: pandas.DataFrame.filter

Calculate a MD5 hash from a string

Was trying to create a string representation of MD5 hash using LINQ, however, none of the answers were LINQ solutions, therefore adding this to the smorgasbord of available solutions.

string result;
using (MD5 hash = MD5.Create())
{
    result = String.Join
    (
        "",
        from ba in hash.ComputeHash
        (
            Encoding.UTF8.GetBytes(observedText)
        ) 
        select ba.ToString("x2")
    );
}

iOS 8 Snapshotting a view that has not been rendered results in an empty snapshot

You can silence the "Snapshotting a view" warning by referencing the view property before presenting the view controller. Doing so causes the view to load and allows iOS render it before taking the snapshot.

UIAlertController *controller = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
controller.modalPresentationStyle = UIModalPresentationPopover;
controller.popoverPresentationController.barButtonItem = (UIBarButtonItem *)sender;

... setup the UIAlertController ... 

[controller view]; // <--- Add to silence the warning.

[self presentViewController:controller animated:YES completion:nil];

SQL: Combine Select count(*) from multiple tables

select 
  (select count(*) from foo) as foo
, (select count(*) from bar) as bar
, ...

Javascript document.getElementById("id").value returning null instead of empty string when the element is an empty text box

Posting your HTML might help a bit. Instead, you can get the element first and then check if it is null or not and then ask for its value rather than just asking for the value directly without knowing if the element is visible on the HTML or not.

element1 = document.getElementById(id);

if(element1 != null)
{
    //code to set the value variable.
}

What is the difference between a framework and a library?

I forget where I saw this definition, but I think it's pretty nice.

A library is a module that you call from your code, and a framework is a module which calls your code.

How does MySQL CASE work?

CASE in MySQL is both a statement and an expression, where each usage is slightly different.

As a statement, CASE works much like a switch statement and is useful in stored procedures, as shown in this example from the documentation (linked above):

DELIMITER |

CREATE PROCEDURE p()
  BEGIN
    DECLARE v INT DEFAULT 1;

    CASE v
      WHEN 2 THEN SELECT v;
      WHEN 3 THEN SELECT 0;
      ELSE
        BEGIN -- Do other stuff
        END;
    END CASE;
  END;
  |

However, as an expression it can be used in clauses:

SELECT *
  FROM employees
  ORDER BY
    CASE title
      WHEN "President" THEN 1
      WHEN "Manager" THEN 2
      ELSE 3
    END, surname

Additionally, both as a statement and as an expression, the first argument can be omitted and each WHEN must take a condition.

SELECT *
  FROM employees
  ORDER BY
    CASE 
      WHEN title = "President" THEN 1
      WHEN title = "Manager" THEN 2
      ELSE 3
    END, surname

I provided this answer because the other answer fails to mention that CASE can function both as a statement and as an expression. The major difference between them is that the statement form ends with END CASE and the expression form ends with just END.

SASS - use variables across multiple files

How about writing some color-based class in a global sass file, thus we don't need to care where variables are. Just like the following:

// base.scss 
@import "./_variables.scss";

.background-color{
    background: $bg-color;
}

and then, we can use the background-color class in any file. My point is that I don't need to import variable.scss in any file, just use it.

Best way to check if MySQL results returned in PHP?

mysqli_fetch_array() returns NULL if there is no row.

In procedural style:

if ( ! $row = mysqli_fetch_array( $result ) ) {
    ... no result ...
}
else {
    ... get the first result in $row ...
}

In Object oriented style:

if ( ! $row = $result->fetch_array() ) {
    ...
}
else {
    ... get the first result in $row ...
}

exception in thread 'main' java.lang.NoClassDefFoundError:

Try doing

javac Hello.java

and then, if it comes up with no compiler errors (which it should not do because I cannot see any bugs in your programme), then type

java Hello

Good tutorial for using HTML5 History API (Pushstate?)

Keep in mind while using HTML5 pushstate if a user copies or bookmarks a deep link and visits it again, then that will be a direct server hit which will 404 so you need to be ready for it and even a pushstate js library won't help you. The easiest solution is to add a rewrite rule to your Nginx or Apache server like so:

Apache (in your vhost if you're using one):

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteRule ^index\.html$ - [L]
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /index.html [L]
 </IfModule>

Nginx

rewrite ^(.+)$ /index.html last;

Select columns in PySpark dataframe

The dataset in ss.csv contains some columns I am interested in:

ss_ = spark.read.csv("ss.csv", header= True, 
                      inferSchema = True)
ss_.columns
['Reporting Area', 'MMWR Year', 'MMWR Week', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Current week', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Current week, flag', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Previous 52 weeks Med', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Previous 52 weeks Med, flag', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Previous 52 weeks Max', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Previous 52 weeks Max, flag', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Cum 2018', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Cum 2018, flag', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Cum 2017', 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Cum 2017, flag', 'Shiga toxin-producing Escherichia coli, Current week', 'Shiga toxin-producing Escherichia coli, Current week, flag', 'Shiga toxin-producing Escherichia coli, Previous 52 weeks Med', 'Shiga toxin-producing Escherichia coli, Previous 52 weeks Med, flag', 'Shiga toxin-producing Escherichia coli, Previous 52 weeks Max', 'Shiga toxin-producing Escherichia coli, Previous 52 weeks Max, flag', 'Shiga toxin-producing Escherichia coli, Cum 2018', 'Shiga toxin-producing Escherichia coli, Cum 2018, flag', 'Shiga toxin-producing Escherichia coli, Cum 2017', 'Shiga toxin-producing Escherichia coli, Cum 2017, flag', 'Shigellosis, Current week', 'Shigellosis, Current week, flag', 'Shigellosis, Previous 52 weeks Med', 'Shigellosis, Previous 52 weeks Med, flag', 'Shigellosis, Previous 52 weeks Max', 'Shigellosis, Previous 52 weeks Max, flag', 'Shigellosis, Cum 2018', 'Shigellosis, Cum 2018, flag', 'Shigellosis, Cum 2017', 'Shigellosis, Cum 2017, flag']

but I only need a few:

columns_lambda = lambda k: k.endswith(', Current week') or k == 'Reporting Area' or k == 'MMWR Year' or  k == 'MMWR Week'

The filter returns the list of desired columns, list is evaluated:

sss = filter(columns_lambda, ss_.columns)
to_keep = list(sss)

the list of desired columns is unpacked as arguments to dataframe select function that return dataset containing only columns in the list:

dfss = ss_.select(*to_keep)
dfss.columns

The result:

['Reporting Area',
 'MMWR Year',
 'MMWR Week',
 'Salmonellosis (excluding Paratyphoid fever andTyphoid fever)†, Current week',
 'Shiga toxin-producing Escherichia coli, Current week',
 'Shigellosis, Current week']

The df.select() has a complementary pair: http://spark.apache.org/docs/2.4.1/api/python/pyspark.sql.html#pyspark.sql.DataFrame.drop

to drop the list of columns.

how to pass parameters to query in SQL (Excel)

It depends on the database to which you're trying to connect, the method by which you created the connection, and the version of Excel that you're using. (Also, most probably, the version of the relevant ODBC driver on your computer.)

The following examples are using SQL Server 2008 and Excel 2007, both on my local machine.

When I used the Data Connection Wizard (on the Data tab of the ribbon, in the Get External Data section, under From Other Sources), I saw the same thing that you did: the Parameters button was disabled, and adding a parameter to the query, something like select field from table where field2 = ?, caused Excel to complain that the value for the parameter had not been specified, and the changes were not saved.

When I used Microsoft Query (same place as the Data Connection Wizard), I was able to create parameters, specify a display name for them, and enter values each time the query was run. Bringing up the Connection Properties for that connection, the Parameters... button is enabled, and the parameters can be modified and used as I think you want.

I was also able to do this with an Access database. It seems reasonable that Microsoft Query could be used to create parameterized queries hitting other types of databases, but I can't easily test that right now.

ng if with angular for string contains

All javascript methods are applicable with angularjs because angularjs itself is a javascript framework so you can use indexOf() inside angular directives

<li ng-repeat="select in Items">   
         <foo ng-repeat="newin select.values">
<span ng-if="newin.label.indexOf(x) !== -1">{{newin.label}}</span></foo>
</li>
//where x is your character to be found

Resize Cross Domain Iframe Height

You need to have access as well on the site that you will be iframing. i found the best solution here: https://gist.github.com/MateuszFlisikowski/91ff99551dcd90971377

yourotherdomain.html

<script type='text/javascript' src="js/jquery.min.js"></script>
<script type='text/javascript'>
  // Size the parent iFrame
  function iframeResize() {
    var height = $('body').outerHeight(); // IMPORTANT: If body's height is set to 100% with CSS this will not work.
    parent.postMessage("resize::"+height,"*");
  }

  $(document).ready(function() {
    // Resize iframe
    setInterval(iframeResize, 1000);
  });
</script>

your website with iframe

<iframe src='example.html' id='edh-iframe'></iframe>
<script type='text/javascript'>
  // Listen for messages sent from the iFrame
  var eventMethod = window.addEventListener ? "addEventListener" : "attachEvent";
  var eventer = window[eventMethod];
  var messageEvent = eventMethod == "attachEvent" ? "onmessage" : "message";

  eventer(messageEvent,function(e) {
    // If the message is a resize frame request
    if (e.data.indexOf('resize::') != -1) {
      var height = e.data.replace('resize::', '');
      document.getElementById('edh-iframe').style.height = height+'px';
    }
  } ,false);
</script>

Apply vs transform on a group object

Two major differences between apply and transform

There are two major differences between the transform and apply groupby methods.

  • Input:
  • apply implicitly passes all the columns for each group as a DataFrame to the custom function.
  • while transform passes each column for each group individually as a Series to the custom function.
  • Output:
  • The custom function passed to apply can return a scalar, or a Series or DataFrame (or numpy array or even list).
  • The custom function passed to transform must return a sequence (a one dimensional Series, array or list) the same length as the group.

So, transform works on just one Series at a time and apply works on the entire DataFrame at once.

Inspecting the custom function

It can help quite a bit to inspect the input to your custom function passed to apply or transform.

Examples

Let's create some sample data and inspect the groups so that you can see what I am talking about:

import pandas as pd
import numpy as np
df = pd.DataFrame({'State':['Texas', 'Texas', 'Florida', 'Florida'], 
                   'a':[4,5,1,3], 'b':[6,10,3,11]})

     State  a   b
0    Texas  4   6
1    Texas  5  10
2  Florida  1   3
3  Florida  3  11

Let's create a simple custom function that prints out the type of the implicitly passed object and then raised an error so that execution can be stopped.

def inspect(x):
    print(type(x))
    raise

Now let's pass this function to both the groupby apply and transform methods to see what object is passed to it:

df.groupby('State').apply(inspect)

<class 'pandas.core.frame.DataFrame'>
<class 'pandas.core.frame.DataFrame'>
RuntimeError

As you can see, a DataFrame is passed into the inspect function. You might be wondering why the type, DataFrame, got printed out twice. Pandas runs the first group twice. It does this to determine if there is a fast way to complete the computation or not. This is a minor detail that you shouldn't worry about.

Now, let's do the same thing with transform

df.groupby('State').transform(inspect)
<class 'pandas.core.series.Series'>
<class 'pandas.core.series.Series'>
RuntimeError

It is passed a Series - a totally different Pandas object.

So, transform is only allowed to work with a single Series at a time. It is impossible for it to act on two columns at the same time. So, if we try and subtract column a from b inside of our custom function we would get an error with transform. See below:

def subtract_two(x):
    return x['a'] - x['b']

df.groupby('State').transform(subtract_two)
KeyError: ('a', 'occurred at index a')

We get a KeyError as pandas is attempting to find the Series index a which does not exist. You can complete this operation with apply as it has the entire DataFrame:

df.groupby('State').apply(subtract_two)

State     
Florida  2   -2
         3   -8
Texas    0   -2
         1   -5
dtype: int64

The output is a Series and a little confusing as the original index is kept, but we have access to all columns.


Displaying the passed pandas object

It can help even more to display the entire pandas object within the custom function, so you can see exactly what you are operating with. You can use print statements by I like to use the display function from the IPython.display module so that the DataFrames get nicely outputted in HTML in a jupyter notebook:

from IPython.display import display
def subtract_two(x):
    display(x)
    return x['a'] - x['b']

Screenshot: enter image description here


Transform must return a single dimensional sequence the same size as the group

The other difference is that transform must return a single dimensional sequence the same size as the group. In this particular instance, each group has two rows, so transform must return a sequence of two rows. If it does not then an error is raised:

def return_three(x):
    return np.array([1, 2, 3])

df.groupby('State').transform(return_three)
ValueError: transform must return a scalar value for each group

The error message is not really descriptive of the problem. You must return a sequence the same length as the group. So, a function like this would work:

def rand_group_len(x):
    return np.random.rand(len(x))

df.groupby('State').transform(rand_group_len)

          a         b
0  0.962070  0.151440
1  0.440956  0.782176
2  0.642218  0.483257
3  0.056047  0.238208

Returning a single scalar object also works for transform

If you return just a single scalar from your custom function, then transform will use it for each of the rows in the group:

def group_sum(x):
    return x.sum()

df.groupby('State').transform(group_sum)

   a   b
0  9  16
1  9  16
2  4  14
3  4  14

twig: IF with multiple conditions

If I recall correctly Twig doesn't support || and && operators, but requires or and and to be used respectively. I'd also use parentheses to denote the two statements more clearly although this isn't technically a requirement.

{%if ( fields | length > 0 ) or ( trans_fields | length > 0 ) %}

Expressions

Expressions can be used in {% blocks %} and ${ expressions }.

Operator    Description
==          Does the left expression equal the right expression?
+           Convert both arguments into a number and add them.
-           Convert both arguments into a number and substract them.
*           Convert both arguments into a number and multiply them.
/           Convert both arguments into a number and divide them.
%           Convert both arguments into a number and calculate the rest of the integer division.
~           Convert both arguments into a string and concatenate them.
or          True if the left or the right expression is true.
and         True if the left and the right expression is true.
not         Negate the expression.

For more complex operations, it may be best to wrap individual expressions in parentheses to avoid confusion:

{% if (foo and bar) or (fizz and (foo + bar == 3)) %}

how to get list of port which are in use on the server

If you mean what ports are listening, you can open a command prompt and write:

netstat

You can write:

netstat /?

for an explanation of all options.

Fastest way to determine if record exists

You can also use

 If EXISTS (SELECT 1 FROM dbo.T1 WHERE T1.Name='Scot')
    BEGIN
         --<Do something>
    END 

ELSE    
     BEGIN
       --<Do something>
     END

Failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED

In my case the answer is pretty simple. Please check carefully the hardcoded url port: it is 8080. For some reason the value has changed to: for example 3030.

Just refresh the port in your ajax url string to the appropriate one.

conn = new WebSocket('ws://localhost:3030'); //should solve the issue

Input type "number" won't resize

change type="number" to type="tel"

How to get config parameters in Symfony2 Twig Templates

You can use parameter substitution in the twig globals section of the config:

Parameter config:

parameters:
    app.version: 0.1.0

Twig config:

twig:
    globals:
        version: '%app.version%'

Twig template:

{{ version }}

This method provides the benefit of allowing you to use the parameter in ContainerAware classes as well, using:

$container->getParameter('app.version');

How to Ping External IP from Java Android

Ping for the google server or any other server

public boolean isConecctedToInternet() {

    Runtime runtime = Runtime.getRuntime();
    try {
        Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
        int     exitValue = ipProcess.waitFor();
        return (exitValue == 0);
    } catch (IOException e)          { e.printStackTrace(); }
    catch (InterruptedException e) { e.printStackTrace(); }
    return false;
}

View HTTP headers in Google Chrome?

I loved the FireFox Header Spy extension so much that i built a HTTP Spy extension for Chrome. I used to use the developer tools too for debugging headers, but now my life is so much better.

Here is a Chrome extension that allows you to view request-, response headers and cookies without any extra clicks right after the page is loaded.

It also handles redirects. It comes with an unobtrusive micro-mode that only shows a hand picked selection of response headers and a normal mode that shows all the information.

https://chrome.google.com/webstore/detail/http-spy/agnoocojkneiphkobpcfoaenhpjnmifb

Enjoy!

Passing command line arguments in Visual Studio 2010?

  • Right click your project in Solution Explorer and select Properties from the menu
  • Go to Configuration Properties -> Debugging
  • Set the Command Arguments in the property list.

Adding Command Line Arguments

Interface vs Base class

I have a rough rule-of-thumb

Functionality: likely to be different in all parts: Interface.

Data, and functionality, parts will be mostly the same, parts different: abstract class.

Data, and functionality, actually working, if extended only with slight changes: ordinary (concrete) class

Data and functionality, no changes planned: ordinary (concrete) class with final modifier.

Data, and maybe functionality: read-only: enum members.

This is very rough and ready and not at all strictly defined, but there is a spectrum from interfaces where everything is intended to be changed to enums where everything is fixed a bit like a read-only file.

Setting action for back button in navigation controller

It isn't possible to do directly. There are a couple alternatives:

  1. Create your own custom UIBarButtonItem that validates on tap and pops if the test passes
  2. Validate the form field contents using a UITextField delegate method, such as -textFieldShouldReturn:, which is called after the Return or Done button is pressed on the keyboard

The downside of the first option is that the left-pointing-arrow style of the back button cannot be accessed from a custom bar button. So you have to use an image or go with a regular style button.

The second option is nice because you get the text field back in the delegate method, so you can target your validation logic to the specific text field sent to the delegate call-back method.

How to return a specific element of an array?

(Edited.) There are two reasons why it doesn't compile: You're missing a semi-colon at the end of this statement:

array3[i]=e1

Also the findOut method doesn't return any value if the array length is 0. Adding a return 0; at the end of the method will make it compile. I've no idea if that will make it do what you want though, as I've no idea what you want it to do.

Visual Studio 2010 - recommended extensions

Code Contracts Editor Extensions, a free extension which provides information about inherited contracts for the method you're currently working on, and a list of contracts for any methods that you're calling. Unfortunately, the latter feature conflicts with Resharper, but the former still works fine.

How to create a video from images with FFmpeg?

See the Create a video slideshow from images – FFmpeg

If your video does not show the frames correctly If you encounter problems, such as the first image is skipped or only shows for one frame, then use the fps video filter instead of -r for the output framerate

ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4

Alternatively the format video filter can be added to the filter chain to replace -pix_fmt yuv420p like "fps=25,format=yuv420p". The advantage of this method is that you can control which filter goes first

ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf "fps=25,format=yuv420p" out.mp4

I tested below parameters, it worked for me

"e:\ffmpeg\ffmpeg.exe" -r 1/5 -start_number 0 -i "E:\images\01\padlock%3d.png" -c:v libx264 -vf "fps=25,format=yuv420p" e:\out.mp4

below parameters also worked but it always skips the first image

"e:\ffmpeg\ffmpeg.exe" -r 1/5 -start_number 0 -i "E:\images\01\padlock%3d.png" -c:v libx264 -r 30 -pix_fmt yuv420p e:\out.mp4

making a video from images placed in different folders

First, add image paths to imagepaths.txt like below.

# this is a comment details https://trac.ffmpeg.org/wiki/Concatenate

file 'E:\images\png\images__%3d.jpg'
file 'E:\images\jpg\images__%3d.jpg'

Sample usage as follows;

"h:\ffmpeg\ffmpeg.exe" -y -r 1/5 -f concat -safe 0 -i "E:\images\imagepaths.txt" -c:v libx264 -vf "fps=25,format=yuv420p" "e:\out.mp4"

-safe 0 parameter prevents Unsafe file name error

Related links

FFmpeg making a video from images placed in different folders

FFMPEG An Intermediate Guide/image sequence

Concatenate – FFmpeg

How to do a redirect to another route with react-router?

How to do a redirect to another route with react-router?

For example, when a user clicks a link <Link to="/" />Click to route</Link> react-router will look for / and you can use Redirect to and send the user somewhere else like the login route.

From the docs for ReactRouterTraining:

Rendering a <Redirect> will navigate to a new location. The new location will override the current location in the history stack, like server-side redirects (HTTP 3xx) do.

import { Route, Redirect } from 'react-router'

<Route exact path="/" render={() => (
  loggedIn ? (
    <Redirect to="/dashboard"/>
  ) : (
    <PublicHomePage/>
  )
)}/>

to: string, The URL to redirect to.

<Redirect to="/somewhere/else"/>

to: object, A location to redirect to.

<Redirect to={{
  pathname: '/login',
  search: '?utm=your+face',
  state: { referrer: currentLocation }
}}/>

Include in SELECT a column that isn't actually in the database

You may want to use:

SELECT Name, 'Unpaid' AS Status FROM table;

The SELECT clause syntax, as defined in MSDN: SELECT Clause (Transact-SQL), is as follows:

SELECT [ ALL | DISTINCT ]
[ TOP ( expression ) [ PERCENT ] [ WITH TIES ] ] 
<select_list> 

Where the expression can be a constant, function, any combination of column names, constants, and functions connected by an operator or operators, or a subquery.

libstdc++-6.dll not found

I placed the libstdc++-6.dll file in the same folder where exe file is generated.

How can I convert a cv::Mat to a gray scale in OpenCv?

May be helpful for late comers.

#include "stdafx.h"
#include "cv.h"
#include "highgui.h"

using namespace cv;
using namespace std;

int main(int argc, char *argv[])
{
  if (argc != 2) {
    cout << "Usage: display_Image ImageToLoadandDisplay" << endl;
    return -1;
}else{
    Mat image;
    Mat grayImage;

    image = imread(argv[1], IMREAD_COLOR);
    if (!image.data) {
        cout << "Could not open the image file" << endl;
        return -1;
    }
    else {
        int height = image.rows;
        int width = image.cols;

        cvtColor(image, grayImage, CV_BGR2GRAY);


        namedWindow("Display window", WINDOW_AUTOSIZE);
        imshow("Display window", image);

        namedWindow("Gray Image", WINDOW_AUTOSIZE);
        imshow("Gray Image", grayImage);
        cvWaitKey(0);
        image.release();
        grayImage.release();
        return 0;
    }

  }

}

Tracking CPU and Memory usage per process

Under Windows 10, the Task Manager can show you cumulative CPU hours. Just head to the "App history" tab and "Delete usage history". Now leave things running for an hour or two:

Windows 10 Cumulative CPU time

What this does NOT do is break down usage in browsers by tab. Quite often inactive tabs will do a tremendous amount of work, with each open tab using energy and slowing your PC.

Is there a way to access the "previous row" value in a SELECT statement?

SQL has no built in notion of order, so you need to order by some column for this to be meaningful. Something like this:

select t1.value - t2.value from table t1, table t2 
where t1.primaryKey = t2.primaryKey - 1

If you know how to order things but not how to get the previous value given the current one (EG, you want to order alphabetically) then I don't know of a way to do that in standard SQL, but most SQL implementations will have extensions to do it.

Here is a way for SQL server that works if you can order rows such that each one is distinct:

select  rank() OVER (ORDER BY id) as 'Rank', value into temp1 from t

select t1.value - t2.value from temp1 t1, temp1 t2 
where t1.Rank = t2.Rank - 1

drop table temp1

If you need to break ties, you can add as many columns as necessary to the ORDER BY.

How to fix JSP compiler warning: one JAR was scanned for TLDs yet contained no TLDs?

The error message states which logger it is using, so set that logger .level:

[jasper] Jul 31, 2012 7:15:15 PM org.apache.jasper.compiler.TldLocationsCache tldScanJar

So the logger is org.apache.jasper.compiler.TldLocationsCache. In your logging.properties file, add this line:

org.apache.jasper.compiler.TldLocationsCache.level = FINE

What is the difference between .*? and .* regular expressions?

Let's say you have:

<a></a>

<(.*)> would match a></a where as <(.*?)> would match a. The latter stops after the first match of >. It checks for one or 0 matches of .* followed by the next expression.

The first expression <(.*)> doesn't stop when matching the first >. It will continue until the last match of >.

Sort an array of objects in React and render them

_x000D_
_x000D_
const list = [
  { qty: 10, size: 'XXL' },
  { qty: 2, size: 'XL' },
  { qty: 8, size: 'M' }
]

list.sort((a, b) => (a.qty > b.qty) ? 1 : -1)

console.log(list)
_x000D_
_x000D_
_x000D_

Out Put :

[
  {
    "qty": 2,
    "size": "XL"
  },
  {
    "qty": 8,
    "size": "M"
  },
  {
    "qty": 10,
    "size": "XXL"
  }
]

Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. Manifest definition does not match the assembly reference

By commenting it out this part on my web.config solved my problem:

<dependentAssembly>
    <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
</dependentAssembly>

But of course you need to make sure you have updated or you have the right version by doing this in your package manager console:

update-package Newtonsoft.Json -reinstall

Use a normal link to submit a form

Two ways. Either create a button and style it so it looks like a link with css, or create a link and use onclick="this.closest('form').submit();return false;".

Normalize data in pandas

This is how you do it column-wise:

[df[col].update((df[col] - df[col].min()) / (df[col].max() - df[col].min())) for col in df.columns]

How to round down to nearest integer in MySQL?

Both Query is used for round down the nearest integer in MySQL

  1. SELECT FLOOR(445.6) ;
  2. SELECT NULL(222.456);

Delaying a jquery script until everything else has loaded

The following script ensures that my_finalFunction runs after your page has been fully loaded with images, stylesheets and external content:

<script>

    document.addEventListener("load", my_finalFunction, false);

    function my_finalFunction(e) {
        /* things to do after all has been loaded */
    }

</script>

A good explanation is provided by kirupa on running your code at the right time, see https://www.kirupa.com/html5/running_your_code_at_the_right_time.htm.

how to "execute" make file

You don't tend to execute the make file itself, rather you execute make, giving it the make file as an argument:

make -f pax.mk

If your make file is actually one of the standard names (like makefile or Makefile), you don't even need to specify it. It'll be picked up by default (if you have more than one of these standard names in your build directory, you better look up the make man page to see which takes precedence).

Linq filter List<string> where it contains a string value from another List<string>

you can do that

var filteredFileList = fileList.Where(fl => filterList.Contains(fl.ToString()));

How to check if a file exists in a shell script

The backdrop to my solution recommendation is the story of a friend who, well into the second week of his first job, wiped half a build-server clean. So the basic task is to figure out if a file exists, and if so, let's delete it. But there are a few treacherous rapids on this river:

  • Everything is a file.

  • Scripts have real power only if they solve general tasks

  • To be general, we use variables

  • We often use -f force in scripts to avoid manual intervention

  • And also love -r recursive to make sure we create, copy and destroy in a timely fashion.

Consider the following scenario:

We have the file we want to delete: filesexists.json

This filename is stored in a variable

<host>:~/Documents/thisfolderexists filevariable="filesexists.json"

We also hava a path variable to make things really flexible

<host>:~/Documents/thisfolderexists pathtofile=".."

<host>:~/Documents/thisfolderexists ls $pathtofile

filesexists.json  history20170728  SE-Data-API.pem  thisfolderexists

So let's see if -e does what it is supposed to. Does the files exist?

<host>:~/Documents/thisfolderexists [ -e $pathtofile/$filevariable ]; echo $?

0

It does. Magic.

However, what would happen, if the file variable got accidentally be evaluated to nuffin'

<host>:~/Documents/thisfolderexists filevariable=""

<host>:~/Documents/thisfolderexists [ -e $pathtofile/$filevariable ]; echo $?

0

What? It is supposed to return with an error... And this is the beginning of the story how that entire folder got deleted by accident

An alternative could be to test specifically for what we understand to be a 'file'

<host>:~/Documents/thisfolderexists filevariable="filesexists.json"

<host>:~/Documents/thisfolderexists test -f $pathtofile/$filevariable; echo $?

0

So the file exists...

<host>:~/Documents/thisfolderexists filevariable=""

<host>:~/Documents/thisfolderexists test -f $pathtofile/$filevariable; echo $?

1

So this is not a file and maybe, we do not want to delete that entire directory

man test has the following to say:

-b FILE

       FILE exists and is block special

-c FILE

       FILE exists and is character special

-d FILE

       FILE exists and is a directory

-e FILE

       FILE exists

-f FILE

       FILE exists and is a regular file

...

-h FILE

       FILE exists and is a symbolic link (same as -L)

how to avoid a new line with p tag?

Use the display: inline CSS property.

Ideal: In the stylesheet:

#container p { display: inline }

Bad/Extreme situation: Inline:

<p style="display:inline">...</p>

How to get text box value in JavaScript

You Need to change your code as below:-

<html>
<body>
<div>
<form align="center" method=post>
    <input id="mainText" type="text" align="center"placeholder="Search">

    <input type="submit" onclick="myFunction()" style="position: absolute; left: 450px"/>
</form>
</div>
<script>
function myFunction(){
    $a= document.getElementById("mainText").value;
    alert($a);
        }
</script>
</body>
</html>

How do I assign a null value to a variable in PowerShell?

If the goal simply is to list all computer objects with an empty description attribute try this

import-module activedirectory  
$domain = "domain.example.com" 
Get-ADComputer -Filter '*' -Properties Description | where { $_.Description -eq $null }

How can two strings be concatenated?

For the first non-paste() answer, we can look at stringr::str_c() (and then toString() below). It hasn't been around as long as this question, so I think it's useful to mention that it also exists.

Very simple to use, as you can see.

tmp <- cbind("GAD", "AB")
library(stringr)
str_c(tmp, collapse = ",")
# [1] "GAD,AB"

From its documentation file description, it fits this problem nicely.

To understand how str_c works, you need to imagine that you are building up a matrix of strings. Each input argument forms a column, and is expanded to the length of the longest argument, using the usual recyling rules. The sep string is inserted between each column. If collapse is NULL each row is collapsed into a single string. If non-NULL that string is inserted at the end of each row, and the entire matrix collapsed to a single string.

Added 4/13/2016: It's not exactly the same as your desired output (extra space), but no one has mentioned it either. toString() is basically a version of paste() with collapse = ", " hard-coded, so you can do

toString(tmp)
# [1] "GAD, AB"

Apply formula to the entire column

Let's say you want to substitute something in an array of string and you don't want to perform the copy-paste on your entire sheet.

Let's take this as an example:

  • String array in column "A": {apple, banana, orange, ..., avocado}
  • You want to substitute the char of "a" to "x" to have: {xpple, bxnxnx, orxnge, ..., xvocado}

To apply this formula on the entire column (array) in a clean an elegant way, you can do:

=ARRAYFORMULA(SUBSTITUE(A:A, "a", "x"))

It works for 2D-arrays as well, let's say:

=ARRAYFORMULA(SUBSTITUE(A2:D83, "a", "x"))

Java: How to convert a File object to a String object in java?

Use a library like Guava or Commons / IO. They have oneliner methods.

Guava:

Files.toString(file, charset);

Commons / IO:

FileUtils.readFileToString(file, charset);

Without such a library, I'd write a helper method, something like this:

public String readFile(File file, Charset charset) throws IOException {
    return new String(Files.readAllBytes(file.toPath()), charset);
}

What do &lt; and &gt; stand for?

&lt; ==  lesser-than == <
&gt; == greater-than == >

Rails: How can I set default values in ActiveRecord?

Some simple cases can be handled by defining a default in the database schema but that doesn't handle a number of trickier cases including calculated values and keys of other models. For these cases I do this:

after_initialize :defaults

def defaults
   unless persisted?
    self.extras||={}
    self.other_stuff||="This stuff"
    self.assoc = [OtherModel.find_by_name('special')]
  end
end

I've decided to use the after_initialize but I don't want it to be applied to objects that are found only those new or created. I think it is almost shocking that an after_new callback isn't provided for this obvious use case but I've made do by confirming whether the object is already persisted indicating that it isn't new.

Having seen Brad Murray's answer this is even cleaner if the condition is moved to callback request:

after_initialize :defaults, unless: :persisted?
              # ":if => :new_record?" is equivalent in this context

def defaults
  self.extras||={}
  self.other_stuff||="This stuff"
  self.assoc = [OtherModel.find_by_name('special')]
end

How does autowiring work in Spring?

Spring dependency inject help you to remove coupling from your classes. Instead of creating object like this:

UserService userService = new UserServiceImpl();

You will be using this after introducing DI:

@Autowired
private UserService userService;

For achieving this you need to create a bean of your service in your ServiceConfiguration file. After that you need to import that ServiceConfiguration class to your WebApplicationConfiguration class so that you can autowire that bean into your Controller like this:

public class AccController {

    @Autowired
    private UserService userService;
} 

You can find a java configuration based POC here example.

How do I parse a HTML page with Node.js

Htmlparser2 by FB55 seems to be a good alternative.

How to get the insert ID in JDBC?

Connection cn = DriverManager.getConnection("Host","user","pass");
Statement st = cn.createStatement("Ur Requet Sql");
int ret  = st.execute();

Bootstrap: add margin/padding space between columns

For those looking to control the space between a dynamic number of columns, try:

<div class="row no-gutters">
    <div class="col">
        <div class="inner">
            <!-- content here -->
        </div>
    </div>
    <div class="col">
        <div class="inner">
            <!-- content here -->
        </div>
    </div>
    <!-- etc. -->
</div>

CSS:

.col:not(:last-child) .inner {
  margin: 2px; // Or whatever you want your spacing to be
}

How to restore/reset npm configuration to default values?

If it's about just one property - let's say you want to temporarily change some default, for instance disable CA checking: you can do it with

npm config set ca ""

To come back to the defaults for that setting, simply

npm config delete ca

To verify, use npm config get ca.

If hasClass then addClass to parent

You can't use $(this) since jQuery doesn't know what it is there. You seem to be overcomplicating things. You can do $('#content h1.aktiv').hide(). There's no reason to test to see if the class exists.

How to select a radio button by default?

They pretty much got it there... just like a checkbox, all you have to do is add the attribute checked="checked" like so:

<input type="radio" checked="checked">

...and you got it.

Cheers!

How to perform runtime type checking in Dart?

Simply call

print(unknownDataType.runtimeType)

on the data.

How do I start/stop IIS Express Server?

An excellent answer given by msigman. I just want to add that in windows 10 you can find IIS Express System Tray (32 bit) process under Visual Studio process:

enter image description here

new Runnable() but no new thread?

Shouldn't creating a new Runnable class make a new second thread?

No. new Runnable does not create second Thread.

What is the purpose of the Runnable class here apart from being able to pass a Runnable class to postAtTime?

Runnable is posted to Handler. This task runs in the thread, which is associated with Handler.

If Handler is associated with UI Thread, Runnable runs in UI Thread.

If Handler is associated with other HandlerThread, Runnable runs in HandlerThread


To explicitly associate Handler to your MainThread ( UI Thread), write below code.

Handler  mHandler = new Handler(Looper.getMainLooper();

If you write is as below, it uses HandlerThread Looper.

HandlerThread handlerThread = new HandlerThread("HandlerThread");
handlerThread.start();
Handler requestHandler = new Handler(handlerThread.getLooper());

Call web service in excel

In Microsoft Excel Office 2007 try installing "Web Service Reference Tool" plugin. And use the WSDL and add the web-services. And use following code in module to fetch the necessary data from the web-service.

Sub Demo()
    Dim XDoc As MSXML2.DOMDocument
    Dim xEmpDetails As MSXML2.IXMLDOMNode
    Dim xParent As MSXML2.IXMLDOMNode
    Dim xChild As MSXML2.IXMLDOMNode
    Dim query As String
    Dim Col, Row As Integer
    Dim objWS As New clsws_GlobalWeather

    Set XDoc = New MSXML2.DOMDocument
    XDoc.async = False
    XDoc.validateOnParse = False
    query = objWS.wsm_GetCitiesByCountry("india")

    If Not XDoc.LoadXML(query) Then  'strXML is the string with XML'
        Err.Raise XDoc.parseError.ErrorCode, , XDoc.parseError.reason
    End If
    XDoc.LoadXML (query)

    Set xEmpDetails = XDoc.DocumentElement
    Set xParent = xEmpDetails.FirstChild
    Worksheets("Sheet3").Cells(1, 1).Value = "Country"
    Worksheets("Sheet3").Cells(1, 1).Interior.Color = RGB(65, 105, 225)
    Worksheets("Sheet3").Cells(1, 2).Value = "City"
    Worksheets("Sheet3").Cells(1, 2).Interior.Color = RGB(65, 105, 225)
    Row = 2
    Col = 1
    For Each xParent In xEmpDetails.ChildNodes
        For Each xChild In xParent.ChildNodes
            Worksheets("Sheet3").Cells(Row, Col).Value = xChild.Text
            Col = Col + 1
        Next xChild
        Row = Row + 1
        Col = 1
    Next xParent
End Sub

How to set a cron job to run at a exact time?

My use case is that I'm on a metered account. Data transfer is limited on weekdays, Mon - Fri, from 6am - 6pm. I am using bandwidth limiting, but somehow, data still slips through, about 1GB per day!

I strongly suspected it's sickrage or sickbeard, doing a high amount of searches. My download machine is called "download." The following was my solution, using the above,for starting, and stopping the download VM, using KVM:

# Stop download Mon-Fri, 6am
0 6 * * 1,2,3,4,5 root          virsh shutdown download
# Start download Mon-Fri, 6pm
0 18 * * 1,2,3,4,5 root         virsh start download

I think this is correct, and hope it helps someone else too.

Nginx -- static file serving confusion with root & alias

as say as @treecoder

In case of the root directive, full path is appended to the root including the location part, whereas in case of the alias directive, only the portion of the path NOT including the location part is appended to the alias.

A picture is worth a thousand words

for root:

enter image description here

for alias:

enter image description here

Custom domain for GitHub project pages

As of Aug 29, 2013, Github's documentation claim that:

Warning: Project pages subpaths like http://username.github.io/projectname will not be redirected to a project's custom domain.

Get Last Part of URL PHP

The absolute simplest way to accomplish this, is with basename()

echo basename('http://domain.com/artist/song/music-videos/song-title/9393903');

Which will print

9393903

Of course, if there is a query string at the end it will be included in the returned value, in which case the accepted answer is a better solution.

Web scraping with Python

I collected together scripts from my web scraping work into this bit-bucket library.

Example script for your case:

from webscraping import download, xpath
D = download.Download()

html = D.get('http://example.com')
for row in xpath.search(html, '//table[@class="spad"]/tbody/tr'):
    cols = xpath.search(row, '/td')
    print 'Sunrise: %s, Sunset: %s' % (cols[1], cols[2])

Output:

Sunrise: 08:39, Sunset: 16:08
Sunrise: 08:39, Sunset: 16:09
Sunrise: 08:39, Sunset: 16:10
Sunrise: 08:40, Sunset: 16:10
Sunrise: 08:40, Sunset: 16:11
Sunrise: 08:40, Sunset: 16:12
Sunrise: 08:40, Sunset: 16:13

Java - No enclosing instance of type Foo is accessible

Thing is an inner class with an automatic connection to an instance of Hello. You get a compile error because there is no instance of Hello for it to attach to. You can fix it most easily by changing it to a static nested class which has no connection:

static class Thing

How to install a previous exact version of a NPM package?

npm install -g npm@version

in which you want to downgrade

npm install -g [email protected]

How to find all the dependencies of a table in sql server

SELECT referencing_schema_name, referencing_entity_name,
case when is_caller_dependent=0 then 'NO' ELSE 'Yes'
END AS is_caller_dependent FROM sys.dm_sql_referencing_entities ('Tablename', 'OBJECT');

Read .doc file with python

I was trying to to the same, I found lots of information on reading .docx but much less on .doc; Anyway, I managed to read the text using the following:

import win32com.client

word = win32com.client.Dispatch("Word.Application")
word.visible = False
wb = word.Documents.Open("myfile.doc")
doc = word.ActiveDocument
print(doc.Range().Text)

$(form).ajaxSubmit is not a function

Ajax Submit form with out page refresh by using jquery ajax method first include library jquery.js and jquery-form.js then create form in html:

<form action="postpage.php" method="POST" id="postForm" >

<div id="flash_success"></div>

name:
<input type="text" name="name" />
password:
<input type="password" name="pass" />
Email:
<input type="text" name="email" />

<input type="submit" name="btn" value="Submit" />
</form>

<script>
  var options = { 
        target:        '#flash_success',  // your response show in this ID
        beforeSubmit:  callValidationFunction,
        success:       YourResponseFunction  
    };
    // bind to the form's submit event
        jQuery('#postForm').submit(function() { 
            jQuery(this).ajaxSubmit(options); 
            return false; 
        }); 


});
function callValidationFunction()
{
 //  validation code for your form HERE
}

function YourResponseFunction(responseText, statusText, xhr, $form)
{
    if(responseText=='success')
    {
        $('#flash_success').html('Your Success Message Here!!!');
        $('body,html').animate({scrollTop: 0}, 800);

    }else
    {
        $('#flash_success').html('Error Msg Here');

    }
}
</script>

Refresh DataGridView when updating data source

Well, it doesn't get much better than that. Officially, you should use

dataGridView1.DataSource = typeof(List); 
dataGridView1.DataSource = itemStates;

It's still a "clear/reset source" kind of solution, but I have yet to find anything else that would reliably refresh the DGV data source.

What does the keyword "transient" mean in Java?

Google is your friend - first hit - also you might first have a look at what serialization is.

It marks a member variable not to be serialized when it is persisted to streams of bytes. When an object is transferred through the network, the object needs to be 'serialized'. Serialization converts the object state to serial bytes. Those bytes are sent over the network and the object is recreated from those bytes. Member variables marked by the java transient keyword are not transferred, they are lost intentionally.

Example from there, slightly modified (thanks @pgras):

public class Foo implements Serializable
 {
   private String saveMe;
   private transient String dontSaveMe;
   private transient String password;
   //...
 }

Row names & column names in R

And another expansion:

# create dummy matrix
set.seed(10)
m <- matrix(round(runif(25, 1, 5)), 5)
d <- as.data.frame(m)

If you want to assign new column names you can do following on data.frame:

# an identical effect can be achieved with colnames()   
names(d) <- LETTERS[1:5]
> d
  A B C D E
1 3 2 4 3 4
2 2 2 3 1 3
3 3 2 1 2 4
4 4 3 3 3 2
5 1 3 2 4 3

If you, however run previous command on matrix, you'll mess things up:

names(m) <- LETTERS[1:5]
> m
     [,1] [,2] [,3] [,4] [,5]
[1,]    3    2    4    3    4
[2,]    2    2    3    1    3
[3,]    3    2    1    2    4
[4,]    4    3    3    3    2
[5,]    1    3    2    4    3
attr(,"names")
 [1] "A" "B" "C" "D" "E" NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA 
[20] NA  NA  NA  NA  NA  NA 

Since matrix can be regarded as two-dimensional vector, you'll assign names only to first five values (you don't want to do that, do you?). In this case, you should stick with colnames().

So there...

Can I use a binary literal in C or C++?

As already answered, the C standards have no way to directly write binary numbers. There are compiler extensions, however, and apparently C++14 includes the 0b prefix for binary. (Note that this answer was originally posted in 2010.)

One popular workaround is to include a header file with helper macros. One easy option is also to generate a file that includes macro definitions for all 8-bit patterns, e.g.:

#define B00000000 0
#define B00000001 1
#define B00000010 2
…

This results in only 256 #defines, and if larger than 8-bit binary constants are needed, these definitions can be combined with shifts and ORs, possibly with helper macros (e.g., BIN16(B00000001,B00001010)). (Having individual macros for every 16-bit, let alone 32-bit, value is not plausible.)

Of course the downside is that this syntax requires writing all the leading zeroes, but this may also make it clearer for uses like setting bit flags and contents of hardware registers. For a function-like macro resulting in a syntax without this property, see bithacks.h linked above.

Composer Update Laravel

When you run composer update, composer generates a file called composer.lock which lists all your packages and the currently installed versions. This allows you to later run composer install, which will install the packages listed in that file, recreating the environment that you were last using.

It appears from your log that some of the versions of packages that are listed in your composer.lock file are no longer available. Thus, when you run composer install, it complains and fails. This is usually no big deal - just run composer update and it will attempt to build a set of packages that work together and write a new composer.lock file.

However, you're running into a different problem. It appears that, in your composer.json file, the original developer has added some pre- or post- update actions that are failing, specifically a php artisan migrate command. This can be avoided by running the following: composer update --no-scripts

This will run the composer update but will skip over the scripts added to the file. You should be able to successfully run the update this way.

However, this does not solve the problem long-term. There are two problems:

  1. A migration is for database changes, not random stuff like compiling assets. Go through the migrations and remove that code from there.

  2. Assets should not be compiled each time you run composer update. Remove that step from the composer.json file.

From what I've read, best practice seems to be compiling assets on an as-needed basis during development (ie. when you're making changes to your LESS files - ideally using a tool like gulp.js) and before deployment.

How to force a SQL Server 2008 database to go Offline

You need to use WITH ROLLBACK IMMEDIATE to boot other conections out with no regards to what or who is is already using it.

Or use WITH NO_WAIT to not hang and not kill existing connections. See http://www.blackwasp.co.uk/SQLOffline.aspx for details

Java Regex to Validate Full Name allow only Spaces and Letters

What about:

  • Peter Müller
  • François Hollande
  • Patrick O'Brian
  • Silvana Koch-Mehrin

Validating names is a difficult issue, because valid names are not only consisting of the letters A-Z.

At least you should use the Unicode property for letters and add more special characters. A first approach could be e.g.:

String regx = "^[\\p{L} .'-]+$";

\\p{L} is a Unicode Character Property that matches any kind of letter from any language

Why do we usually use || over |? What is the difference?

In addition to short-circuiting, another thing to keep in mind is that doing a bitwise logic operation on values that can be other than 0 or 1 has a very different meaning than conditional logic. While it USUALLY is the same for | and ||, with & and && you get very different results (e.g. 2 & 4 is 0/false while 2 && 4 is 1/true).

If the thing you're getting from a function is actually an error code and you're testing for non-0-ness, this can matter quite a lot.

This isn't as much of an issue in Java where you have to explicitly typecast to boolean or compare with 0 or the like, but in other languages with similar syntax (C/C++ et al) it can be quite confusing.

Also, note that & and | can only apply to integer-type values, and not everything that can be equivalent to a boolean test. Again, in non-Java languages, there are quite a few things that can be used as a boolean with an implicit != 0 comparison (pointers, floats, objects with an operator bool(), etc.) and bitwise operators are almost always nonsensical in those contexts.

Deserialize JSON with C#

I agree with Icarus (would have commented if I could), but instead of using a CustomObject class, I would use a Dictionary (in case Facebook adds something).

private class MyFacebookClass
{
    public IList<IDictionary<string, string>> data { get; set; }
}

or

private class MyFacebookClass
{
    public IList<IDictionary<string, object>> data { get; set; }
}

Python: Select subset from list based on index set

Assuming you only have the list of items and a list of true/required indices, this should be the fastest:

property_asel = [ property_a[index] for index in good_indices ]

This means the property selection will only do as many rounds as there are true/required indices. If you have a lot of property lists that follow the rules of a single tags (true/false) list you can create an indices list using the same list comprehension principles:

good_indices = [ index for index, item in enumerate(good_objects) if item ]

This iterates through each item in good_objects (while remembering its index with enumerate) and returns only the indices where the item is true.


For anyone not getting the list comprehension, here is an English prose version with the code highlighted in bold:

list the index for every group of index, item that exists in an enumeration of good objects, if (where) the item is True

error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' -- Missing /var/run/mysqld/mysqld.sock

Same here on Ubuntu 18.04

Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'

  1. mysqld.sock= actually resides under folder /run/mysqld/
  2. ?> / ll /var/run
    lrwxrwxrwx 1 root root 4 Nov 1 2018 /var/run -> /run/

hmmm... Does that mean a symbolic link won't work? That's weird...

VBA: Counting rows in a table (list object)

You can use this:

    Range("MyTable[#Data]").Rows.Count

You have to distinguish between a table which has either one row of data or no data, as the previous code will return "1" for both cases. Use this to test for an empty table:

    If WorksheetFunction.CountA(Range("MyTable[#Data]"))

multiple packages in context:component-scan, spring config

<context:component-scan base-package="x.y.z"/>

will work since the rest of the packages are sub packages of "x.y.z". Thus, you dont need to mention each package individually.

Determine the line of code that causes a segmentation fault?

You could also use a core dump and then examine it with gdb. To get useful information you also need to compile with the -g flag.

Whenever you get the message:

 Segmentation fault (core dumped)

a core file is written into your current directory. And you can examine it with the command

 gdb your_program core_file

The file contains the state of the memory when the program crashed. A core dump can be useful during the deployment of your software.

Make sure your system doesn't set the core dump file size to zero. You can set it to unlimited with:

ulimit -c unlimited

Careful though! that core dumps can become huge.

How can I list ALL grants a user received?

Following query can be used to get all privileges of one user .. Just provide user name in first query and you will get all privileges to that

WITH users AS (SELECT 'SCHEMA_USER' usr FROM dual), Roles AS (SELECT granted_role FROM dba_role_privs rp JOIN users ON rp.GRANTEE = users.usr UNION SELECT granted_role FROM role_role_privs WHERE role IN (SELECT granted_role FROM dba_role_privs rp JOIN users ON rp.GRANTEE = users.usr)), tab_privilage AS (SELECT OWNER, TABLE_NAME, PRIVILEGE FROM role_tab_privs rtp JOIN roles r ON rtp.role = r.granted_role UNION SELECT OWNER, TABLE_NAME, PRIVILEGE FROM Dba_Tab_Privs dtp JOIN Users ON dtp.grantee = users.usr), sys_privileges AS (SELECT privilege FROM dba_sys_privs dsp JOIN users ON dsp.grantee = users.usr) SELECT * FROM tab_privilage ORDER BY owner, table_name --SELECT * FROM sys_privileges