Programs & Examples On #Libsvm

LIBSVM is a library for Support Vector Machines

cannot open shared object file: No such file or directory

When working on a supercomputer, I received this error when I ran:

module load python/3.4.0
screen
python

To resolve the error, I simply needed to reload the module in the screen terminal:

module load python/3.4.0
python

Loop through all the files with a specific extension

I agree withe the other answers regarding the correct way to loop through the files. However the OP asked:

The code above doesn't work, do you know why?

Yes!

An excellent article What is the difference between test, [ and [[ ?] explains in detail that among other differences, you cannot use expression matching or pattern matching within the test command (which is shorthand for [ )


Feature            new test [[    old test [           Example

Pattern matching    = (or ==)    (not available)    [[ $name = a* ]] || echo "name does not start with an 'a': $name"

Regular Expression     =~        (not available)    [[ $(date) =~ ^Fri\ ...\ 13 ]] && echo "It's Friday the 13th!"
matching

So this is the reason your script fails. If the OP is interested in an answer with the [[ syntax (which has the disadvantage of not being supported on as many platforms as the [ command), I would be happy to edit my answer to include it.

EDIT: Any protips for how to format the data in the answer as a table would be helpful!

Check if any ancestor has a class using jQuery

You can use parents method with specified .class selector and check if any of them matches it:

if ($elem.parents('.left').length != 0) {
    //someone has this class
}

How to concatenate two strings in C++?

//String appending
#include <iostream>
using namespace std;

void stringconcat(char *str1, char *str2){
    while (*str1 != '\0'){
        str1++;
    }

    while(*str2 != '\0'){
        *str1 = *str2;
        str1++;
        str2++;
    }
}

int main() {
    char str1[100];
    cin.getline(str1, 100);  
    char str2[100];
    cin.getline(str2, 100);

    stringconcat(str1, str2);

    cout<<str1;
    getchar();
    return 0;
}

Spring Boot + JPA : Column name annotation ignored

teteArg, thank you so much. Just an added information so, everyone bumping into this question will be able to understand why.

What teteArg said is indicated on the Spring Boot Common Properties: http://docs.spring.io/spring-boot/docs/current/reference/html/common-application-properties.html

Apparently, spring.jpa.hibernate.naming.strategy is not a supported property for Spring JPA implementation using Hibernate 5.

Reset par to the default values at startup

An alternative solution for preventing functions to change the user par. You can set the default parameters early on the function, so that the graphical parameters and layout will not be changed during the function execution. See ?on.exit for further details.

on.exit(layout(1))
opar<-par(no.readonly=TRUE)
on.exit(par(opar),add=TRUE,after=FALSE)

Relative instead of Absolute paths in Excel VBA

You can provide more flexibility to your users by provide Browser Button to them

Private Sub btn_browser_file_Click()
Dim xRow As Long
Dim sh1 As Worksheet
Dim xl_app As Excel.Application
Dim xl_wk As Excel.Workbook
Dim WS As Workbook
Dim xDirect$, xFname$, InitialFoldr$
InitialFoldr$ = "C:\"
With Application.FileDialog(msoFileDialogFolderPicker)
    .InitialFileName = Application.DefaultFilePath & "\"
    .Title = "Please select a folder to list Files from"
    .InitialFileName = InitialFoldr$
    .Show
    Range("H13").Activate
    If .SelectedItems.Count <> 0 Then
        xDirect$ = .SelectedItems(1) & "\"
         Range("h12").Value = xDirect$
        xFname$ = Dir(xDirect$, 7)
        Do While xFname$ <> ""
         If (Format(FileDateTime(xDirect$ & "\" & xFname$), "MM/DD/YYYY") > Format(Range("H10").Value, "MM/DD/YYYY")) Then
            ActiveCell.Offset(xRow) = xFname$
            xRow = xRow + 1
            xFname$ = Dir
            Else
            xFname$ = Dir
            xRow = xRow
        End If
        Loop
    End If
End With

with this piece of code you can achieve this, easily. Tested code

Python MySQLdb TypeError: not all arguments converted during string formatting

You can try this code:

cur.execute( "SELECT * FROM records WHERE email LIKE %s", (search,) )

You can see the documentation

Limit results in jQuery UI Autocomplete

Adding to Andrew's answer, you can even introduce a maxResults property and use it this way:

$("#auto").autocomplete({ 
    maxResults: 10,
    source: function(request, response) {
        var results = $.ui.autocomplete.filter(src, request.term);
        response(results.slice(0, this.options.maxResults));
    }
});

jsFiddle: http://jsfiddle.net/vqwBP/877/

This should help code readability and maintainability!

A server with the specified hostname could not be found

That fixed the problem for me, when trying to upgrade to El Capitan:

sudo softwareupdate --clear-catalog

jquery function setInterval

try this declare the function outside the ready event.

    $(document).ready(function(){    
       setInterval(swapImages(),1000); 
    });


    function swapImages(){

    var active = $('.active'); 
    var next = ($('.active').next().length > 0) ? $('.active').next() :         $('#siteNewsHead img:first');
    active.removeClass('active');
    next.addClass('active');
}

Copy every nth line from one sheet to another

In my opinion the answers given to this question are too specific. Here's an attempt at a more general answer with two different approaches and a complete example.

The OFFSET approach

OFFSET takes 3 mandatory arguments. The first is a given cell that we want to offset from. The next two are the number of rows and columns we want to offset (downwards and rightwards). OFFNET returns the content of the cell this results in. For instance, OFFSET(A1, 1, 2) returns the contents of cell C2 because A1 is cell (1,1) and if we add (1,2) to that we get (2,3) which corresponds to cell C2.

To get this to return every nth row from another column, we can make use of the ROW function. When this function is given no argument, it returns the row number of the current cell. We can thus combine OFFSET and ROW to make a function that returns every nth cell by adding a multiplier to the value returned by ROW. For instance OFFSET(A$1,ROW()*3,0). Note the use of $1 in the target cell. If this is not used, the offsetting will offset from different cells, thus in effect adding 1 to the multiplier.

The ADDRESS + INDIRECT approach

ADDRESS takes two integer inputs and returns the address/name of the cell as a string. For instance, ADDRESS(1,1) return "$A$1". INDIRECT takes the address of a cell and returns the contents. For instance, INDIRECT("A1") returns the contents of cell A1 (it also accepts input with $'s in it). If we use ROW inside ADDRESS with a multiplier, we can get the address of every nth cell. For instance, ADDRESS(ROW(), 1) in row 1 will return "$A$1", in row 2 will return "$A$2" and so on. So, if we put this inside INDIRECT, we can get the content of every nth cells. For instance, INDIRECT(ADDRESS(1*ROW()*3,1)) returns the contents of every 3rd cell in the first column when dragged downwards.

Example

Consider the following screenshot of a spreadsheet. The headers (first row) contains the call used in the rows below. enter image description here Column A contains our example data. In this case, it's just the positive integers (the counting continues outside the shown area). These are the values that we want to get every 3rd of, that is, we want to get 1, 4, 7, 10, and so on.

Column B contains an incorrect attempt at using the OFFSET approach but where we forgot to use $. As can be seen, while we multiply by 3, we actually get every 4th row.

Column C contains an incorrect attempt at using the OFFSET approach where we remembered to use $, but forgot to subtract. So while we do get every 3rd value, we skipped some values (1 and 4).

Column D contains a correct function using the OFFSET approach.

Column E contains an incorrect attempt at using the ADDRESS + INDRECT approach, but where we forgot to subtract. Thus we skipped some rows initially. The same problem as with column C.

Column F contains a correct function using the ADDRESS + INDRECT approach.

Handling the TAB character in Java

Or you could just perform a trim() on the string to handle the case when people use spaces instead of tabs (unless you are reading makefiles)

Download file and automatically save it to folder

Why not just bypass the WebClient's file handling pieces altogether. Perhaps something similar to this:

    private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e)
    {
        e.Cancel = true;
        WebClient client = new WebClient();

        client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted);

        client.DownloadDataAsync(e.Url);
    }

    void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
    {
        string filepath = textBox1.Text;
        File.WriteAllBytes(filepath, e.Result);
        MessageBox.Show("File downloaded");
    }

List of lists into numpy array

Again, after searching for the problem of converting nested lists with N levels into an N-dimensional array I found nothing, so here's my way around it:

import numpy as np

new_array=np.array([[[coord for coord in xk] for xk in xj] for xj in xi], ndmin=3) #this case for N=3

CodeIgniter Select Query

When use codeIgniter Framework then refer this active records link. how the data interact with structure and more.

The following functions allow you to build SQL SELECT statements.

Selecting Data

$this->db->get();

Runs the selection query and returns the result. Can be used by itself to retrieve all records from a table:

$query = $this->db->get('mytable');

With access to each row

$query = $this->db->get('mytable');

foreach ($query->result() as $row)
{
    echo $row->title;
}

Where clues

$this->db->get_where();

EG:

 $query = $this->db->get_where('mytable', array('id' => $id), $limit, $offset);

Select field

$this->db->select('title, content, date');

$query = $this->db->get('mytable');

// Produces: SELECT title, content, date FROM mytable

E.G

$this->db->select('(SELECT SUM(payments.amount) FROM payments WHERE payments.invoice_id=4') AS amount_paid', FALSE); 
$query = $this->db->get('mytable');

How do I restart a service on a remote machine in Windows?

One way would be to enable telnet server on the machin you want to control services on (add/remove windows components)

Open dos prompt
Type telnet yourmachineip/name
Log on
type net start &serviceName* e.g. w3svc

This will start IIS or you can use net stop to stop a service.

Depending on your setup you need to look at a way of securing the telnet connection as I think its unencrypted.

json.net has key method?

JObject.ContainsKey(string propertyName) has been made as public method in 11.0.1 release

Documentation - https://www.newtonsoft.com/json/help/html/M_Newtonsoft_Json_Linq_JObject_ContainsKey.htm

Detect whether current Windows version is 32 bit or 64 bit

I use this:

@echo off
if "%PROCESSOR_ARCHITECTURE%"=="AMD64" (
 echo 64 BIT
) else (
 echo 32 BIT
)

It works on Windows XP, tested it on Windows XP Professional Both 64 bit and 32 bit.

Convert string into Date type on Python

You can do that with datetime.strptime()

Example:

>>> from datetime import datetime
>>> datetime.strptime('2012-02-10' , '%Y-%m-%d')
datetime.datetime(2012, 2, 10, 0, 0)
>>> _.isoweekday()
5

You can find the table with all the strptime directive here.


To increment by 2 days if .isweekday() == 6, you can use timedelta():

>>> import datetime
>>> date = datetime.datetime.strptime('2012-02-11' , '%Y-%m-%d')
>>> if date.isoweekday() == 6:
...     date += datetime.timedelta(days=2)
... 
>>> date
datetime.datetime(2012, 2, 13, 0, 0)
>>> date.strftime('%Y-%m-%d')   # if you want a string again
'2012-02-13'

What are database constraints?

constraints are conditions, that can validate specific condition. Constraints related with database are Domain integrity, Entity integrity, Referential Integrity, User Defined Integrity constraints etc.

How do you clear Apache Maven's cache?

Delete the artifacts (or the full local repo) from c:\Users\<username>\.m2\repository by hand.

Service has zero application (non-infrastructure) endpoints

The endpoint should also have the namespace:

 <endpoint address="uri" binding="wsHttpBinding" contract="Namespace.Interface" />

what is the use of xsi:schemaLocation?

An xmlns is a unique identifier within the document - it doesn't have to be a URI to the schema:

XML namespaces provide a simple method for qualifying element and attribute names used in Extensible Markup Language documents by associating them with namespaces identified by URI references.

xsi:schemaLocation is supposed to give a hint as to the actual schema location:

can be used in a document to provide hints as to the physical location of schema documents which may be used for assessment.

What is the equivalent to getLastInsertId() in Cakephp?

I think it works with getLastInsertId() if you use InnoDB Tables in your MySQL Database. You also can use $this->Model->id

How create a new deep copy (clone) of a List<T>?

C# 9 records and with expressions can make it a little easier, especially if your type has many properties.

You can use something like:

var books2 = books1.Select(b => b with { }).ToList();

I did this as an example:

record Book
{
    public string Name { get; set; }
}

static void Main()
{
    List<Book> books1 = new List<Book>()
    {
        new Book { Name = "Book1.1" },
        new Book { Name = "Book1.2" },
        new Book { Name = "Book1.3" }
    };

    var books2 = books1.Select(b => b with { }).ToList();

    books2[0].Name = "Changed";
    books2[1].Name = "Changed";

    Console.WriteLine("Book1");
    foreach (var item in books1)
    {
        Console.WriteLine(item);
    }

    Console.WriteLine("Book2");
    foreach (var item in books2)
    {
        Console.WriteLine(item);
    }
}

And the result was:

Book1

Book { Name = Book1.1 }

Book { Name = Book1.2 }

Book { Name = Book1.3 }

Book2

Book { Name = Changed }

Book { Name = Changed }

Book { Name = Book1.3 }

json Uncaught SyntaxError: Unexpected token :

You've told jQuery to expect a JSONP response, which is why jQuery has added the callback=jQuery16406345664265099913_1319854793396&_=1319854793399 part to the URL (you can see this in your dump of the request).

What you're returning is JSON, not JSONP. Your response looks like

{"red" : "#f00"}

and jQuery is expecting something like this:

jQuery16406345664265099913_1319854793396({"red" : "#f00"})

If you actually need to use JSONP to get around the same origin policy, then the server serving colors.json needs to be able to actually return a JSONP response.

If the same origin policy isn't an issue for your application, then you just need to fix the dataType in your jQuery.ajax call to be json instead of jsonp.

Trigger a Travis-CI rebuild without pushing a commit?

I know you said without pushing a commit, but something that is handy, if you are working on a branch other than master, is to commit an empty commit.

git commit --allow-empty -m "Trigger"

You can rebase in the end and remove squash/remove the empty commits and works across all git hooks :)

Declaring a boolean in JavaScript using just var

Variables in Javascript don't have a type. Non-zero, non-null, non-empty and true are "true". Zero, null, undefined, empty string and false are "false".

There's a Boolean type though, as are literals true and false.

Passing a varchar full of comma delimited values to a SQL Server IN function

Best and simple approach.

DECLARE @AccumulateKeywordCopy NVARCHAR(2000),@IDDupCopy NVARCHAR(50);
SET @AccumulateKeywordCopy ='';
SET @IDDupCopy ='';
SET @IDDup = (SELECT CONVERT(VARCHAR(MAX), <columnName>) FROM <tableName> WHERE <clause>)

SET @AccumulateKeywordCopy = ','+@AccumulateKeyword+',';
SET @IDDupCopy = ','+@IDDup +',';
SET @IDDupCheck = CHARINDEX(@IDDupCopy,@AccumulateKeywordCopy)

How to resize html canvas element?

Prototypes can be a hassle to work with, and from the _PROTO part of the error it appears your error is caused by, say, HTMLCanvasElement.prototype.width, possibly as an attempt to resize all the canvases at once.

As a suggestion, if you are trying to resize a number of canvases at once, you could try:

<canvas></canvas>
<canvas></canvas>
<canvas></canvas>
<script type="text/javascript">
    ...
</script>

In the JavaScript, instead of invoking a prototype, try this:

$$ = function(){
    return document.querySelectorAll.apply(document,arguments);
}
for(var i in $$('canvas')){
    canvas = $$('canvas')[i];
    canvas.width = canvas.width+100;
    canvas.height = canvas.height+100;
}

This would resize all the canvases by adding 100 px to their size, as is demonstrated in this example


Hope this helped.

Parameter "stratify" from method "train_test_split" (scikit Learn)

This stratify parameter makes a split so that the proportion of values in the sample produced will be the same as the proportion of values provided to parameter stratify.

For example, if variable y is a binary categorical variable with values 0 and 1 and there are 25% of zeros and 75% of ones, stratify=y will make sure that your random split has 25% of 0's and 75% of 1's.

Fake "click" to activate an onclick method

var clickEvent = new MouseEvent('click', {
  view: window,
  bubbles: true,
  cancelable: true
});
var element = document.getElementById('element-id'); 
var cancelled = !element.dispatchEvent(clickEvent);
if (cancelled) {
  // A handler called preventDefault.
  alert("cancelled");
} else {
  // None of the handlers called preventDefault.
  alert("not cancelled");
}

element.dispatchEvent is supported in all major browsers. The example above is based on an sample simulateClick() function on MDN.

Use multiple css stylesheets in the same html page

You never refer to a specific style sheet. All CSS rules in a document are internally fused into one.

In the case of rules in both style sheets that apply to the same element with the same specificity, the style sheet embedded later will override the earlier one.

You can use an element inspector like Firebug to see which rules apply, and which ones are overridden by others.

How to tag docker image with docker-compose

Original answer Nov 20 '15:

No option for a specific tag as of Today. Docker compose just does its magic and assigns a tag like you are seeing. You can always have some script call docker tag <image> <tag> after you call docker-compose.

Now there's an option as described above or here

build: ./dir
image: webapp:tag

System.Timers.Timer vs System.Threading.Timer

This article offers a fairly comprehensive explanation:

"Comparing the Timer Classes in the .NET Framework Class Library" - also available as a .chm file

The specific difference appears to be that System.Timers.Timer is geared towards multithreaded applications and is therefore thread-safe via its SynchronizationObject property, whereas System.Threading.Timer is ironically not thread-safe out-of-the-box.

I don't believe that there is a difference between the two as it pertains to how small your intervals can be.

Regular expression to extract numbers from a string

you could use something like:

[^0-9]+([0-9]+)[^0-9]+([0-9]+).+

Then get the first and second capture groups.

How to access the last value in a vector?

Combining lindelof's and Gregg Lind's ideas:

last <- function(x) { tail(x, n = 1) }

Working at the prompt, I usually omit the n=, i.e. tail(x, 1).

Unlike last from the pastecs package, head and tail (from utils) work not only on vectors but also on data frames etc., and also can return data "without first/last n elements", e.g.

but.last <- function(x) { head(x, n = -1) }

(Note that you have to use head for this, instead of tail.)

How to get the current time in milliseconds in C Programming

quick answer

#include<stdio.h>   
#include<time.h>   

int main()   
{   
    clock_t t1, t2;  
    t1 = clock();   
    int i;
    for(i = 0; i < 1000000; i++)   
    {   
        int x = 90;  
    }   

    t2 = clock();   

    float diff = ((float)(t2 - t1) / 1000000.0F ) * 1000;   
    printf("%f",diff);   

    return 0;   
}

Set encoding and fileencoding to utf-8 in Vim

TL;DR

In the first case with set encoding=utf-8, you'll change the output encoding that is shown in the terminal.

In the second case with set fileencoding=utf-8, you'll change the output encoding of the file that is written.

As stated by @Dennis, you can set them both in your ~/.vimrc if you always want to work in utf-8.

More details

From the wiki of VIM about working with unicode

"encoding sets how vim shall represent characters internally. Utf-8 is necessary for most flavors of Unicode."

"fileencoding sets the encoding for a particular file (local to buffer); :setglobal sets the default value. An empty value can also be used: it defaults to same as 'encoding'. Or you may want to set one of the ucs encodings, It might make the same disk file bigger or smaller depending on your particular mix of characters. Also, IIUC, utf-8 is always big-endian (high bit first) while ucs can be big-endian or little-endian, so if you use it, you will probably need to set 'bomb" (see below)."

SQL string value spanning multiple lines in query

SQL Server allows the following (be careful to use single quotes instead of double)

UPDATE User
SET UserId = 12345
   , Name = 'J Doe'
   , Location = 'USA'
   , Bio='my bio
spans 
multiple
lines!'
WHERE UserId = 12345

get UTC timestamp in python with datetime

A simple solution without using external modules:

from datetime import datetime, timezone

dt = datetime(2008, 1, 1, 0, 0, 0, 0)
int(dt.replace(tzinfo=timezone.utc).timestamp())

Compile error: package javax.servlet does not exist

This happens because java does not provide with Servlet-api.jar to import directly, so you need to import it externally like from Tomcat , for this we need to provide the classpath of lib folder from which we will be importing the Servlet and it's related Classes.

For Windows you can apply this method:

  1. open command prompt
  2. type
 javac -classpath "C:\Program Files\Apache Software Foundation\Tomcat 9.0\lib\*;" YourFileName.java 
     
  1. It will take all jar files which needed for importing Servlet, HttpServlet ,etc and compile your java file.

  2. You can add multiple classpaths Eg.

javac -classpath "C:\Users\Project1\WEB-INF\lib\*; C:\Program Files\Apache Software Foundation\Tomcat 9.0\lib\*;" YourFileName.java

CSS: On hover show and hide different div's at the same time?

http://jsfiddle.net/MBLZx/

Here is the code

_x000D_
_x000D_
 .showme{ _x000D_
   display: none;_x000D_
 }_x000D_
 .showhim:hover .showme{_x000D_
   display : block;_x000D_
 }_x000D_
 .showhim:hover .ok{_x000D_
   display : none;_x000D_
 }
_x000D_
 <div class="showhim">_x000D_
     HOVER ME_x000D_
     <div class="showme">hai</div>_x000D_
     <div class="ok">ok</div>_x000D_
</div>_x000D_
_x000D_
   
_x000D_
_x000D_
_x000D_

Replace string in text file using PHP

Does this work:

$msgid = $_GET['msgid'];

$oldMessage = '';

$deletedFormat = '';

//read the entire string
$str=file_get_contents('msghistory.txt');

//replace something in the file string - this is a VERY simple example
$str=str_replace($oldMessage, $deletedFormat,$str);

//write the entire string
file_put_contents('msghistory.txt', $str);

Check if a path represents a file or a folder

   private static boolean isValidFolderPath(String path) {
    File file = new File(path);
    if (!file.exists()) {
      return file.mkdirs();
    }
    return true;
  }

user authentication libraries for node.js?

Here are two popular Github libraries for node js authentication:

https://github.com/jaredhanson/passport ( suggestible )

https://nodejsmodules.org/pkg/everyauth

How to apply two CSS classes to a single element

Separate 'em with a space.

<div class="c1 c2"></div>

Display MessageBox in ASP

<!DOCTYPE html>
<html>
<body>
<button onclick="myFunction()">Try it</button>

<script>
function myFunction()
{
    alert("Hello!");
}
</script>

</body>
</html>

Copy Paste this in an HTML file and run in any browser , this should show an alert using javascript.

Kendo grid date column not formatting

Try formatting the date in the kendo grid as:

columns.Bound(x => x.LastUpdateDate).ClientTemplate("#= kendo.toString(LastUpdateDate, \"MM/dd/yyyy hh:mm tt\") #");

Difference between Fact table and Dimension table?

  1. The fact table mainly consists of business facts and foreign keys that refer to primary keys in the dimension tables. A dimension table consists mainly of descriptive attributes that are textual fields.
  2. A dimension table contains a surrogate key, natural key, and a set of attributes. On the contrary, a fact table contains a foreign key, measurements, and degenerated dimensions.
  3. Dimension tables provide descriptive or contextual information for the measurement of a fact table. On the other hand, fact tables provide the measurements of an enterprise.
  4. When comparing the size of the two tables, a fact table is bigger than a dimensional table. In a comparison table, more dimensions are presented than the fact tables. In a fact table, less numbers of facts are observed.
  5. The dimension table has to be loaded first. While loading the fact tables, one should have to look at the dimension table. This is because the fact table has measures, facts, and foreign keys that are the primary keys in the dimension table.

Read more: Dimension Table and Fact Table | Difference Between | Dimension Table vs Fact Table http://www.differencebetween.net/technology/hardware-technology/dimension-table-and-fact-table/#ixzz3SBp8kPzo

Maven: best way of linking custom external JAR to my project?

update We have since just installed our own Nexus server, much easier and cleaner.

At our company we had some jars that we some jars that were common but were not hosted in any maven repositories, nor did we want to have them in local storage. We created a very simple mvn (public) repo on Github (but you can host it on any server or locally):
note that this is only ideal for managing a few rarely chaning jar files

  1. Create repo on GitHub:
    https://github.com/<user_name>/mvn-repo/

  2. Add Repository in pom.xml
    (Make note that the full path raw file will be a bit different than the repo name)

    <repository>
        <id>project-common</id>
        <name>Project Common</name>
        <url>https://github.com/<user_name>/mvn-repo/raw/master/</url>
    </repository>
    
  3. Add dependency to host (Github or private server)
    a. All you need to know is that files are stored in the pattern mentioned by @glitch
    /groupId/artifactId/version/artifactId-version.jar
    b. On your host create the folders to match this pattern.
    i.e if you have a jar file named service-sdk-0.0.1.jar, create the folder service-sdk/service-sdk/0.0.1/ and place the jar file service-sdk-0.0.1.jar into it.
    c. Test it by trying to download the jar from a browser (in our case: https://github.com/<user_name>/mvn-repo/raw/master/service-sdk/service-sdk/0.0.1/service-sdk-0.0.1.jar

  4. Add dependency to your pom.xml file:

    <dependency>
        <groupId>service-sdk</groupId>
        <artifactId>service-sdk</artifactId>
        <version>0.0.1</version>
    </dependency>
    
  5. Enjoy

Edit seaborn legend

Took me a while to read through the above. This was the answer for me:

import seaborn as sns
import matplotlib.pyplot as plt
tips = sns.load_dataset("tips")

g = sns.lmplot(
    x="total_bill", 
    y="tip", 
    hue="smoker", 
    data=tips,  
    legend=False
)

plt.legend(title='Smoker', loc='upper left', labels=['Hell Yeh', 'Nah Bruh'])
plt.show(g)

Reference this for more arguments: matplotlib.pyplot.legend

enter image description here

Why is my power operator (^) not working?

Instead of using ^, use 'pow' function which is a predefined function which performs the Power operation and it can be used by including math.h header file.

^ This symbol performs BIT-WISE XOR operation in C, C++.

Replace a^i with pow(a,i).

How to change an image on click using CSS alone?

No, you will need scripting to place a click Event handler on the Element that does what you want.

Maintain/Save/Restore scroll position when returning to a ListView

Am posting this because I am surprised nobody had mentioned this.

After user clicks the back button he will return to the listview in the same state as he went out of it.

This code will override the "up" button to behave the same way as the back button so in the case of Listview -> Details -> Back to Listview (and no other options) this is the simplest code to maintain the scrollposition and the content in the listview.

 public boolean onOptionsItemSelected(MenuItem item) {
     switch (item.getItemId()) {
         case android.R.id.home:
             onBackPressed();
             return(true);
     }
     return(super.onOptionsItemSelected(item)); }

Caution: If you can go to another activity from the details activity the up button will return you back to that activity so you will have to manipulate the backbutton history in order for this to work.

How to open PDF file in a new tab or window instead of downloading it (using asp.net)?

You have to create either another page or generic handler with the code to generate your pdf. Then that event gets triggered and the person is redirected to that page.

SQL - How do I get only the numbers after the decimal?

You can use FLOOR:

select x, ABS(x) - FLOOR(ABS(x))
from (
    select 2.938 as x
) a

Output:

x                                       
-------- ----------
2.938    0.938

Or you can use SUBSTRING:

select x, SUBSTRING(cast(x as varchar(max)), charindex(cast(x as varchar(max)), '.') + 3, len(cast(x as varchar(max))))
from (
    select 2.938 as x
) a

How to extract an assembly from the GAC?

Open the Command Prompt and Type :

cd  c:\windows\assembly\GAC_MSIL 

xcopy . C:\GacDump /s /y

This should give the dump of the entire GAC

Enjoy!

What is 0x10 in decimal?

It's a hex number and is 16 decimal.

Abstract methods in Python

Abstract base classes are deep magic. Periodically I implement something using them and am amazed at my own cleverness, very shortly afterwards I find myself completely confused by my own cleverness (this may well just be a personal limitation though).

Another way of doing this (should be in the python std libs if you ask me) is to make a decorator.

def abstractmethod(method):
    """
    An @abstractmethod member fn decorator.
    (put this in some library somewhere for reuse).

    """
    def default_abstract_method(*args, **kwargs):
        raise NotImplementedError('call to abstract method ' 
                                  + repr(method))
    default_abstract_method.__name__ = method.__name__    
    return default_abstract_method


class Shape(object):

    def __init__(self, shape_name):
       self.shape = shape_name

    @abstractmethod
    def foo(self):
        print "bar"
        return

class Rectangle(Shape):
    # note you don't need to do the constructor twice either
    pass  

r = Rectangle("x")
r.foo()

I didn't write the decorator. It just occurred to me someone would have. You can find it here: http://code.activestate.com/recipes/577666-abstract-method-decorator/ Good one jimmy2times. Note the discussion at the bottom of that page r.e. type safety of the decorator. (That could be fixed with the inspect module if anyone was so inclined).

How to Update/Drop a Hive Partition?

You can update a Hive partition by, for example:

ALTER TABLE logs PARTITION(year = 2012, month = 12, day = 18) 
SET LOCATION 'hdfs://user/darcy/logs/2012/12/18';

This command does not move the old data, nor does it delete the old data. It simply sets the partition to the new location.

To drop a partition, you can do

ALTER TABLE logs DROP IF EXISTS PARTITION(year = 2012, month = 12, day = 18);

Hope it helps!

Giving UIView rounded corners

Please import Quartzcore framework then you have to set setMaskToBounds to TRUE this the very important line.

Then: [[yourView layer] setCornerRadius:5.0f];

javac not working in windows command prompt

The path will only be set for the administrator account. Therefore it is important to launch command prompt as administrator, if you are not already.

Opening a CHM file produces: "navigation to the webpage was canceled"

The definitive solution is to allow the InfoTech protocol to work in the intranet zone.

Add the following value to the registry and the problem should be solved:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions]
"MaxAllowedZone"=dword:00000001

More info here: http://support.microsoft.com/kb/896054

Pretty print in MongoDB shell as default

Give a try to Mongo-hacker(node module), it alway prints pretty. https://github.com/TylerBrock/mongo-hacker

More it enhances mongo shell (supports only ver>2.4, current ver is 3.0), like

  • Colorization
  • Additional shell commands (count documents/count docs/etc)
  • API Additions (db.collection.find({ ... }).last(), db.collection.find({ ... }).reverse(), etc)
  • Aggregation Framework

I am using for while in production env, no problems yet.

Adding Text to DataGridView Row Header

yes you can

DataGridView1.Rows[0].HeaderCell.Value = "my text";

CSS/Javascript to force html table row on a single line

If you hide the overflow and there is a long word, you risk loosing that word, so you could go one step further and use the "word-wrap" css attribute.

http://msdn.microsoft.com/en-us/library/ms531186(VS.85).aspx

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

This error usually occurs if you have not included the xmlns:mm properly, it occurs usually in the first line of code.

for me it was..

xmlns:mm="http://millennialmedia.com/android/schema"

that i missed in first line of the code

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:mm="http://millennialmedia.com/android/schema"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_marginTop="50dp"
android:layout_marginBottom="50dp"
android:background="@android:color/transparent" >

How to get the host name of the current machine as defined in the Ansible hosts file?

You can limit the scope of a playbook by changing the hosts header in its plays without relying on your special host label ‘local’ in your inventory. Localhost does not need a special line in inventories.

- name: run on all except local
  hosts: all:!local

Using setTimeout to delay timing of jQuery actions

You can also use jQuery's delay() method instead of setTimeout(). It'll give you much more readable code. Here's an example from the docs:

$( "#foo" ).slideUp( 300 ).delay( 800 ).fadeIn( 400 );

The only limitation (that I'm aware of) is that it doesn't give you a way to clear the timeout. If you need to do that then you're better off sticking with all the nested callbacks that setTimeout thrusts upon you.

How to dismiss notification after action has been clicked

I found that when you use the action buttons in expanded notifications, you have to write extra code and you are more constrained.

You have to manually cancel your notification when the user clicks an action button. The notification is only cancelled automatically for the default action.

Also if you start a broadcast receiver from the button, the notification drawer doesn't close.

I ended up creating a new NotificationActivity to address these issues. This intermediary activity without any UI cancels the notification and then starts the activity I really wanted to start from the notification.

I've posted sample code in a related post Clicking Android Notification Actions does not close Notification drawer.

Parallel foreach with asynchronous lambda

I've created an extension method for this which makes use of SemaphoreSlim and also allows to set maximum degree of parallelism

    /// <summary>
    /// Concurrently Executes async actions for each item of <see cref="IEnumerable<typeparamref name="T"/>
    /// </summary>
    /// <typeparam name="T">Type of IEnumerable</typeparam>
    /// <param name="enumerable">instance of <see cref="IEnumerable<typeparamref name="T"/>"/></param>
    /// <param name="action">an async <see cref="Action" /> to execute</param>
    /// <param name="maxDegreeOfParallelism">Optional, An integer that represents the maximum degree of parallelism,
    /// Must be grater than 0</param>
    /// <returns>A Task representing an async operation</returns>
    /// <exception cref="ArgumentOutOfRangeException">If the maxActionsToRunInParallel is less than 1</exception>
    public static async Task ForEachAsyncConcurrent<T>(
        this IEnumerable<T> enumerable,
        Func<T, Task> action,
        int? maxDegreeOfParallelism = null)
    {
        if (maxDegreeOfParallelism.HasValue)
        {
            using (var semaphoreSlim = new SemaphoreSlim(
                maxDegreeOfParallelism.Value, maxDegreeOfParallelism.Value))
            {
                var tasksWithThrottler = new List<Task>();

                foreach (var item in enumerable)
                {
                    // Increment the number of currently running tasks and wait if they are more than limit.
                    await semaphoreSlim.WaitAsync();

                    tasksWithThrottler.Add(Task.Run(async () =>
                    {
                        await action(item).ContinueWith(res =>
                        {
                            // action is completed, so decrement the number of currently running tasks
                            semaphoreSlim.Release();
                        });
                    }));
                }

                // Wait for all tasks to complete.
                await Task.WhenAll(tasksWithThrottler.ToArray());
            }
        }
        else
        {
            await Task.WhenAll(enumerable.Select(item => action(item)));
        }
    }

Sample Usage:

await enumerable.ForEachAsyncConcurrent(
    async item =>
    {
        await SomeAsyncMethod(item);
    },
    5);

Best practice for storing and protecting private API keys in applications

Based on bitter experience, and after consulting with an IDA-Pro expert the best solution is to move a key part of the code into a DLL/SharedObject, then fetch it from a server and load at runtime.

Sensitive data must be encoded as it's very easy to do something like this:

$ strings libsecretlib.so | grep My
  My_S3cr3t_P@$$W0rD

How does a Java HashMap handle different objects with the same hash code?

You can find excellent information at http://javarevisited.blogspot.com/2011/02/how-hashmap-works-in-java.html

To Summarize:

HashMap works on the principle of hashing

put(key, value): HashMap stores both key and value object as Map.Entry. Hashmap applies hashcode(key) to get the bucket. if there is collision ,HashMap uses LinkedList to store object.

get(key): HashMap uses Key Object's hashcode to find out bucket location and then call keys.equals() method to identify correct node in LinkedList and return associated value object for that key in Java HashMap.

How to execute a shell script from C in Linux?

If you're ok with POSIX, you can also use popen()/pclose()

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

int main(void) {
/* ls -al | grep '^d' */
  FILE *pp;
  pp = popen("ls -al", "r");
  if (pp != NULL) {
    while (1) {
      char *line;
      char buf[1000];
      line = fgets(buf, sizeof buf, pp);
      if (line == NULL) break;
      if (line[0] == 'd') printf("%s", line); /* line includes '\n' */
    }
    pclose(pp);
  }
  return 0;
}

Printing out a linked list using toString

When the JVM tries to run your application, it calls your main method statically; something like this:

LinkedList.main();

That means there is no instance of your LinkedList class. In order to call your toString() method, you can create a new instance of your LinkedList class.

So the body of your main method should be like this:

public static void main(String[] args){
    // creating an instance of LinkedList class
    LinkedList ll = new LinkedList();

    // adding some data to the list
    ll.insertFront(1);
    ll.insertFront(2);
    ll.insertFront(3);
    ll.insertBack(4);

    System.out.println(ll.toString());
}

sql: check if entry in table A exists in table B

SELECT *
FROM   B
WHERE  NOT EXISTS (SELECT 1 
                   FROM   A 
                   WHERE  A.ID = B.ID)

Using jQuery to compare two arrays of Javascript objects

I also found this when looking to do some array comparisons with jQuery. In my case I had strings which I knew to be arrays:

var needle = 'apple orange';
var haystack = 'kiwi orange banana apple plum';

But I cared if it was a complete match or only a partial match, so I used something like the following, based off of Sudhakar R's answer:

function compareStrings( needle, haystack ){
  var needleArr = needle.split(" "),
    haystackArr = haystack.split(" "),
    compare = $(haystackArr).not(needleArr).get().length;

  if( compare == 0 ){
    return 'all';
  } else if ( compare == haystackArr.length  ) {
    return 'none';
  } else {
    return 'partial';
  }
}

How to detect duplicate values in PHP array?

$count = 0;
$output ='';
$ischeckedvalueArray = array();
for ($i=0; $i < sizeof($array); $i++) {
    $eachArrayValue = $array[$i];
    if(! in_array($eachArrayValue, $ischeckedvalueArray)) {
        for( $j=$i; $j < sizeof($array); $j++) {
            if ($array[$j] === $eachArrayValue) {
                $count++;
            }
        }
        $ischeckedvalueArray[] = $eachArrayValue;
        $output .= $eachArrayValue. " Repated ". $count."<br/>";
        $count = 0;
    }

}

echo $output;

Django Admin - change header 'Django administration' text

Just go to admin.py file and add this line in the file :

admin.site.site_header = "My Administration"

Removing duplicate objects with Underscore for Javascript

Implementation of Shiplu's answer.

var foo = [ { "a" : "1" }, { "b" : "2" }, { "a" : "1" } ];

var x = _.uniq( _.collect( foo, function( x ){
    return JSON.stringify( x );
}));

console.log( x ); // returns [ { "a" : "1" }, { "b" : "2" } ]

Adding a legend to PyPlot in Matplotlib in the simplest manner possible

Add a label= to each of your plot() calls, and then call legend(loc='upper left').

Consider this sample (tested with Python 3.8.0):

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 20, 1000)
y1 = np.sin(x)
y2 = np.cos(x)

plt.plot(x, y1, "-b", label="sine")
plt.plot(x, y2, "-r", label="cosine")
plt.legend(loc="upper left")
plt.ylim(-1.5, 2.0)
plt.show()

enter image description here Slightly modified from this tutorial: http://jakevdp.github.io/mpl_tutorial/tutorial_pages/tut1.html

How to draw a circle with text in the middle?

Using this code it will be responsive also.

<div class="circle">ICON</div>

.circle {
  position: relative;
  display: inline-block;
  width: 100%;
  height: 0;
  padding: 50% 0;
  border-radius: 50%;
  /* Just making it pretty */
  -webkit-box-shadow: 0 4px 0 0 rgba(0, 0, 0, 0.1);
  box-shadow: 0 4px 0 0 rgba(0, 0, 0, 0.1);
  text-shadow: 0 4px 0 rgba(0, 0, 0, 0.1);
  background: #38a9e4;
  color: white;
  font-family: Helvetica, Arial Black, sans;
  font-size: 48px;
  text-align: center;
}

Laravel Eloquent compare date from datetime field

If you're still wondering how to solve it.

I use

$protected $dates = ['created_at','updated_at','aired'];

In my model and in my where i do

where('aired','>=',time())

So just use the unix to compaire in where.

In views on the otherhand you have to use the date object.

Hope it helps someone!

How to do jquery code AFTER page loading?

And if you want to run a second function after the first one finishes, see this stackoverflow answer.

How do I deploy Node.js applications as a single executable file?

Not to beat a dead horse, but the solution you're describing sounds a lot like Node-Webkit.

From the Git Page:

node-webkit is an app runtime based on Chromium and node.js. You can write native apps in HTML and JavaScript with node-webkit. It also lets you call Node.js modules directly from the DOM and enables a new way of writing native applications with all Web technologies.

These instructions specifically detail the creation of a single file app that a user can execute, and this portion describes the external dependencies.

I'm not sure if it's the exact solution, but it seems pretty close.

Hope it helps!

AngularJS - Multiple ng-view in single template

I believe you can accomplish it by just having single ng-view. In the main template you can have ng-include sections for sub views, then in the main controller define model properties for each sub template. So that they will bind automatically to ng-include sections. This is same as having multiple ng-view

You can check the example given in ng-include documentation

in the example when you change the template from dropdown list it changes the content. Here assume you have one main ng-view and instead of manually selecting sub content by selecting drop down, you do it as when main view is loaded.

What does <> mean?

I instinctively read it as "different from". "!=" hits me milliseconds after.

Using GSON to parse a JSON array

Gson gson = new Gson();
Wrapper[] arr = gson.fromJson(str, Wrapper[].class);

class Wrapper{
    int number;
    String title;       
}

Seems to work fine. But there is an extra , Comma in your string.

[
    { 
        "number" : "3",
        "title" : "hello_world"
    },
    { 
        "number" : "2",
        "title" : "hello_world"
    }
]

CSS to hide INPUT BUTTON value text

I had the opposite problem (worked in Internet Explorer, but not in Firefox). For Internet Explorer, you need to add left padding, and for Firefox, you need to add transparent color. So here is our combined solution for a 16px x 16px icon button:

input.iconButton
{
    font-size: 1em;
    color: transparent; /* Fix for Firefox */
    border-style: none;
    border-width: 0;
    padding: 0 0 0 16px !important; /* Fix for Internet Explorer */
    text-align: left;
    width: 16px;
    height: 16px;
    line-height: 1 !important;
    background: transparent url(../images/button.gif) no-repeat scroll 0 0;
    overflow: hidden;
    cursor: pointer;
}

CSS: How to change colour of active navigation page menu

The CSS :active state means the active state of the clicked link - the moment when you clicked on it, but not released the mouse button yet, for example. It doesn't know which page you're on and can't apply any styles to the menu items.

To fix your problem you have to create a class and add it manually to the current page's menu:

a.active { color: #f00 }

<ul>
    <li><a href="index.php" class="active">HOME</a></li>
    <li><a href="two.php">PORTFOLIO</a></li>
    <li><a href="three.php">ABOUT</a></li>
    <li><a href="four.php">CONTACT</a></li>
    <li><a href="five.php">SHOP</a></li>
</ul>

Task.Run with Parameter(s)?

From now you can also :

Action<int> action = (o) => Thread.Sleep(o);
int param = 10;
await new TaskFactory().StartNew(action, param)

git - remote add origin vs remote set-url origin

Below will reinitialize your local repo; also clearing remote repos (ie origin):

git init

Then below, will create 'origin' if it doesn't exist:

git remote add origin [repo-url]

Else, you can use the set-url subcommand to edit an existing remote:

git remote set-url origin [repo-url]

Also, you can check existing remotes with

git remote -v

Hope this helps!

How can I generate a self-signed certificate with SubjectAltName using OpenSSL?

Can someone help me with the exact syntax?

It's a three-step process, and it involves modifying the openssl.cnf file. You might be able to do it with only command line options, but I don't do it that way.

Find your openssl.cnf file. It is likely located in /usr/lib/ssl/openssl.cnf:

$ find /usr/lib -name openssl.cnf
/usr/lib/openssl.cnf
/usr/lib/openssh/openssl.cnf
/usr/lib/ssl/openssl.cnf

On my Debian system, /usr/lib/ssl/openssl.cnf is used by the built-in openssl program. On recent Debian systems it is located at /etc/ssl/openssl.cnf

You can determine which openssl.cnf is being used by adding a spurious XXX to the file and see if openssl chokes.


First, modify the req parameters. Add an alternate_names section to openssl.cnf with the names you want to use. There are no existing alternate_names sections, so it does not matter where you add it.

[ alternate_names ]

DNS.1        = example.com
DNS.2        = www.example.com
DNS.3        = mail.example.com
DNS.4        = ftp.example.com

Next, add the following to the existing [ v3_ca ] section. Search for the exact string [ v3_ca ]:

subjectAltName      = @alternate_names

You might change keyUsage to the following under [ v3_ca ]:

keyUsage = digitalSignature, keyEncipherment

digitalSignature and keyEncipherment are standard fare for a server certificate. Don't worry about nonRepudiation. It's a useless bit thought up by computer science guys/gals who wanted to be lawyers. It means nothing in the legal world.

In the end, the IETF (RFC 5280), browsers and CAs run fast and loose, so it probably does not matter what key usage you provide.


Second, modify the signing parameters. Find this line under the CA_default section:

# Extension copying option: use with caution.
# copy_extensions = copy

And change it to:

# Extension copying option: use with caution.
copy_extensions = copy

This ensures the SANs are copied into the certificate. The other ways to copy the DNS names are broken.


Third, generate your self-signed certificate:

$ openssl genrsa -out private.key 3072
$ openssl req -new -x509 -key private.key -sha256 -out certificate.pem -days 730
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
...

Finally, examine the certificate:

$ openssl x509 -in certificate.pem -text -noout
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 9647297427330319047 (0x85e215e5869042c7)
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, ST=MD, L=Baltimore, O=Test CA, Limited, CN=Test CA/[email protected]
        Validity
            Not Before: Feb  1 05:23:05 2014 GMT
            Not After : Feb  1 05:23:05 2016 GMT
        Subject: C=US, ST=MD, L=Baltimore, O=Test CA, Limited, CN=Test CA/[email protected]
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (3072 bit)
                Modulus:
                    00:e2:e9:0e:9a:b8:52:d4:91:cf:ed:33:53:8e:35:
                    ...
                    d6:7d:ed:67:44:c3:65:38:5d:6c:94:e5:98:ab:8c:
                    72:1c:45:92:2c:88:a9:be:0b:f9
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
                34:66:39:7C:EC:8B:70:80:9E:6F:95:89:DB:B5:B9:B8:D8:F8:AF:A4
            X509v3 Authority Key Identifier:
                keyid:34:66:39:7C:EC:8B:70:80:9E:6F:95:89:DB:B5:B9:B8:D8:F8:AF:A4

            X509v3 Basic Constraints: critical
                CA:FALSE
            X509v3 Key Usage:
                Digital Signature, Non Repudiation, Key Encipherment, Certificate Sign
            X509v3 Subject Alternative Name:
                DNS:example.com, DNS:www.example.com, DNS:mail.example.com, DNS:ftp.example.com
    Signature Algorithm: sha256WithRSAEncryption
         3b:28:fc:e3:b5:43:5a:d2:a0:b8:01:9b:fa:26:47:8e:5c:b7:
         ...
         71:21:b9:1f:fa:30:19:8b:be:d2:19:5a:84:6c:81:82:95:ef:
         8b:0a:bd:65:03:d1

Python: One Try Multiple Except

Yes, it is possible.

try:
   ...
except FirstException:
   handle_first_one()

except SecondException:
   handle_second_one()

except (ThirdException, FourthException, FifthException) as e:
   handle_either_of_3rd_4th_or_5th()

except Exception:
   handle_all_other_exceptions()

See: http://docs.python.org/tutorial/errors.html

The "as" keyword is used to assign the error to a variable so that the error can be investigated more thoroughly later on in the code. Also note that the parentheses for the triple exception case are needed in python 3. This page has more info: Catch multiple exceptions in one line (except block)

What's the difference between __PRETTY_FUNCTION__, __FUNCTION__, __func__?

__PRETTY_FUNCTION__ handles C++ features: classes, namespaces, templates and overload

main.cpp

#include <iostream>

namespace N {
    class C {
        public:
            template <class T>
            static void f(int i) {
                (void)i;
                std::cout << "__func__            " << __func__ << std::endl
                          << "__FUNCTION__        " << __FUNCTION__ << std::endl
                          << "__PRETTY_FUNCTION__ " << __PRETTY_FUNCTION__ << std::endl;
            }
            template <class T>
            static void f(double f) {
                (void)f;
                std::cout << "__PRETTY_FUNCTION__ " << __PRETTY_FUNCTION__ << std::endl;
            }
    };
}

int main() {
    N::C::f<char>(1);
    N::C::f<void>(1.0);
}

Compile and run:

g++ -ggdb3 -O0 -std=c++11 -Wall -Wextra -pedantic -o main.out main.cpp
./main.out

Output:

__func__            f
__FUNCTION__        f
__PRETTY_FUNCTION__ static void N::C::f(int) [with T = char]
__PRETTY_FUNCTION__ static void N::C::f(double) [with T = void]

You may also be interested in stack traces with function names: print call stack in C or C++

Tested in Ubuntu 19.04, GCC 8.3.0.

C++20 std::source_location::function_name

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1208r5.pdf went into C++20, so we have yet another way to do it.

The documentation says:

constexpr const char* function_name() const noexcept;

6 Returns: If this object represents a position in the body of a function, returns an implementation-defined NTBS that should correspond to the function name. Otherwise, returns an empty string.

where NTBS means "Null Terminated Byte String".

I'll give it a try when support arrives to GCC, GCC 9.1.0 with g++-9 -std=c++2a still doesn't support it.

https://en.cppreference.com/w/cpp/utility/source_location claims usage will be like:

#include <iostream>
#include <string_view>
#include <source_location>
 
void log(std::string_view message,
         const std::source_location& location std::source_location::current()
) {
    std::cout << "info:"
              << location.file_name() << ":"
              << location.line() << ":"
              << location.function_name() << " "
              << message << '\n';
}
 
int main() {
    log("Hello world!");
}

Possible output:

info:main.cpp:16:main Hello world!

so note how this returns the caller information, and is therefore perfect for usage in logging, see also: Is there a way to get function name inside a C++ function?

How to print_r $_POST array?

Came across this 'implode' recently.

May be useful to output arrays. http://in2.php.net/implode

echo 'Variables: ' . implode( ', ', $_POST);

Is there a Max function in SQL Server that takes two values like Math.Max in .NET?

You can do something like this:

select case when o.NegotiatedPrice > o.SuggestedPrice 
then o.NegotiatedPrice
else o.SuggestedPrice
end

css label width not taking effect

Make it a block first, then float left to stop pushing the next block in to a new line.

#report-upload-form label {
                           padding-left:26px;
                           width:125px;
                           text-transform: uppercase;
                           display:block;
                           float:left
}

SQL Error: ORA-00913: too many values

You should specify column names as below. It's good practice and probably solve your problem

insert into abc.employees (col1,col2) 
select col1,col2 from employees where employee_id=100; 

EDIT:

As you said employees has 112 columns (sic!) try to run below select to compare both tables' columns

select * 
from ALL_TAB_COLUMNS ATC1
left join ALL_TAB_COLUMNS ATC2 on ATC1.COLUMN_NAME = ATC1.COLUMN_NAME 
                               and  ATC1.owner = UPPER('2nd owner')
where ATC1.owner = UPPER('abc')
and ATC2.COLUMN_NAME is null
AND ATC1.TABLE_NAME = 'employees'

and than you should upgrade your tables to have the same structure.

Nginx fails to load css files

I was having the same issue and none of the above made any difference for me what did work was having my location php above any other location blocks.

location ~ [^/]\.php(/|$) {
fastcgi_split_path_info  ^(.+\.php)(/.+)$;
fastcgi_index            index.php;
fastcgi_pass             unix:/var/run/php/php7.3-fpm.sock;
include                  fastcgi_params;
fastcgi_param   PATH_INFO       $fastcgi_path_info;
fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;
}
** The below is specifically for moodle **
location /dataroot/ {
internal;
alias <full_moodledata_path>; # ensure the path ends with /
}

Read the current full URL with React?

window.location.href is what you're looking for.

How can I solve the error 'TS2532: Object is possibly 'undefined'?

Edit / Update:

If you are using Typescript 3.7 or newer you can now also do:

    const data = change?.after?.data();

    if(!data) {
      console.error('No data here!');
       return null
    }

    const maxLen = 100;
    const msgLen = data.messages.length;
    const charLen = JSON.stringify(data).length;

    const batch = db.batch();

    if (charLen >= 10000 || msgLen >= maxLen) {

      // Always delete at least 1 message
      const deleteCount = msgLen - maxLen <= 0 ? 1 : msgLen - maxLen
      data.messages.splice(0, deleteCount);

      const ref = db.collection("chats").doc(change.after.id);

      batch.set(ref, data, { merge: true });

      return batch.commit();
    } else {
      return null;
    }

Original Response

Typescript is saying that change or data is possibly undefined (depending on what onUpdate returns).

So you should wrap it in a null/undefined check:

if(change && change.after && change.after.data){
    const data = change.after.data();

    const maxLen = 100;
    const msgLen = data.messages.length;
    const charLen = JSON.stringify(data).length;

    const batch = db.batch();

    if (charLen >= 10000 || msgLen >= maxLen) {

      // Always delete at least 1 message
      const deleteCount = msgLen - maxLen <= 0 ? 1 : msgLen - maxLen
      data.messages.splice(0, deleteCount);

      const ref = db.collection("chats").doc(change.after.id);

      batch.set(ref, data, { merge: true });

      return batch.commit();
    } else {
      return null;
    }
}

If you are 100% sure that your object is always defined then you can put this:

const data = change.after!.data();

Adding placeholder text to textbox

txtUsuario.Attributes.Add("placeholder", "Texto");

Why does MSBuild look in C:\ for Microsoft.Cpp.Default.props instead of c:\Program Files (x86)\MSBuild? ( error MSB4019)

I was facing the same issue with MSBuild for VS 17

I solved this by applying the following steps:

  • In my case the Microsoft.Cpp.Default.props file was located at C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\Common7\IDE\VC\VCTargets so I created VCTragetsPath string in the registry under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0 with value C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\Common7\IDE\VC\VCTargets

  • I also made my Jenkins run as an admin user

This solved my issue.

How to escape single quotes in MySQL

Maybe you could take a look at function QUOTE in the MySQL manual.

Android ListView Selector Color

The list selector drawable is a StateListDrawable — it contains reference to multiple drawables for each state the list can be, like selected, focused, pressed, disabled...

While you can retrieve the drawable using getSelector(), I don't believe you can retrieve a specific Drawable from a StateListDrawable, nor does it seem possible to programmatically retrieve the colour directly from a ColorDrawable anyway.

As for setting the colour, you need a StateListDrawable as described above. You can set this on your list using the android:listSelector attribute, defining the drawable in XML like this:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:state_enabled="false" android:state_focused="true"
        android:drawable="@drawable/item_disabled" />
  <item android:state_pressed="true"
        android:drawable="@drawable/item_pressed" />
  <item android:state_focused="true"
        android:drawable="@drawable/item_focused" />
</selector>

How to set HTML5 required attribute in Javascript?

And the jquery version:

$('input').attr('required', true)
$('input').attr('required', false)

I know it's beyond the question, but maybe someone will find this helpful :)

Reading file from Workspace in Jenkins with Groovy script

If you already have the Groovy (Postbuild) plugin installed, I think it's a valid desire to get this done with (generic) Groovy instead of installing a (specialized) plugin.

That said, you can get the workspace using manager.build.workspace.getRemote(). Don't forget to add File.separator between path and file name.

XAMPP - Port 80 in use by "Unable to open process" with PID 4! 12

Click services on the Xampp control panel (filename is services.msc, extra info).

First, look for IIS, if it is running. Stop it (stop this service option on the left after clicking on the service name.). Then, this is the main problem, Look for Web deployment Service (not the exact name though it has Web deployment at the beginning.). Stop this service too. Try again and Apache should work.

If you are running Skype, exit out of that too, run Apache, then launch Skype

Interface defining a constructor signature?

You could do this with generics trick, but it still is vulnerable to what Jon Skeet wrote:

public interface IHasDefaultConstructor<T> where T : IHasDefaultConstructor<T>, new()
{
}

Class that implements this interface must have parameterless constructor:

public class A : IHasDefaultConstructor<A> //Notice A as generic parameter
{
    public A(int a) { } //compile time error
}

Get name of object or class

I was facing a similar difficulty and none of the solutions presented here were optimal for what I was working on. What I had was a series of functions to display content in a modal and I was trying to refactor it under a single object definition making the functions, methods of the class. The problem came in when I found one of the methods created some nav-buttons inside the modal themselves which used an onClick to one of the functions -- now an object of the class. I have considered (and am still considering) other methods to handle these nav buttons, but I was able to find the variable name for the class itself by sweeping the variables defined in the parent window. What I did was search for anything matching the 'instanceof' my class, and in case there might be more than one, I compared a specific property that was likely to be unique to each instance:

var myClass = function(varName)
{
    this.instanceName = ((varName != null) && (typeof(varName) == 'string') && (varName != '')) ? varName : null;

    /**
     * caching autosweep of window to try to find this instance's variable name
     **/
    this.getInstanceName = function() {
        if(this.instanceName == null)
        {
            for(z in window) {
                if((window[z] instanceof myClass) && (window[z].uniqueProperty === this.uniqueProperty)) {
                    this.instanceName = z;
                    break;
                }
            }
        }
        return this.instanceName;
    }
}

What is the difference between atomic / volatile / synchronized?

You are specifically asking about how they internally work, so here you are:

No synchronization

private int counter;

public int getNextUniqueIndex() {
  return counter++; 
}

It basically reads value from memory, increments it and puts back to memory. This works in single thread but nowadays, in the era of multi-core, multi-CPU, multi-level caches it won't work correctly. First of all it introduces race condition (several threads can read the value at the same time), but also visibility problems. The value might only be stored in "local" CPU memory (some cache) and not be visible for other CPUs/cores (and thus - threads). This is why many refer to local copy of a variable in a thread. It is very unsafe. Consider this popular but broken thread-stopping code:

private boolean stopped;

public void run() {
    while(!stopped) {
        //do some work
    }
}

public void pleaseStop() {
    stopped = true;
}

Add volatile to stopped variable and it works fine - if any other thread modifies stopped variable via pleaseStop() method, you are guaranteed to see that change immediately in working thread's while(!stopped) loop. BTW this is not a good way to interrupt a thread either, see: How to stop a thread that is running forever without any use and Stopping a specific java thread.

AtomicInteger

private AtomicInteger counter = new AtomicInteger();

public int getNextUniqueIndex() {
  return counter.getAndIncrement();
}

The AtomicInteger class uses CAS (compare-and-swap) low-level CPU operations (no synchronization needed!) They allow you to modify a particular variable only if the present value is equal to something else (and is returned successfully). So when you execute getAndIncrement() it actually runs in a loop (simplified real implementation):

int current;
do {
  current = get();
} while(!compareAndSet(current, current + 1));

So basically: read; try to store incremented value; if not successful (the value is no longer equal to current), read and try again. The compareAndSet() is implemented in native code (assembly).

volatile without synchronization

private volatile int counter;

public int getNextUniqueIndex() {
  return counter++; 
}

This code is not correct. It fixes the visibility issue (volatile makes sure other threads can see change made to counter) but still has a race condition. This has been explained multiple times: pre/post-incrementation is not atomic.

The only side effect of volatile is "flushing" caches so that all other parties see the freshest version of the data. This is too strict in most situations; that is why volatile is not default.

volatile without synchronization (2)

volatile int i = 0;
void incIBy5() {
  i += 5;
}

The same problem as above, but even worse because i is not private. The race condition is still present. Why is it a problem? If, say, two threads run this code simultaneously, the output might be + 5 or + 10. However, you are guaranteed to see the change.

Multiple independent synchronized

void incIBy5() {
  int temp;
  synchronized(i) { temp = i }
  synchronized(i) { i = temp + 5 }
}

Surprise, this code is incorrect as well. In fact, it is completely wrong. First of all you are synchronizing on i, which is about to be changed (moreover, i is a primitive, so I guess you are synchronizing on a temporary Integer created via autoboxing...) Completely flawed. You could also write:

synchronized(new Object()) {
  //thread-safe, SRSLy?
}

No two threads can enter the same synchronized block with the same lock. In this case (and similarly in your code) the lock object changes upon every execution, so synchronized effectively has no effect.

Even if you have used a final variable (or this) for synchronization, the code is still incorrect. Two threads can first read i to temp synchronously (having the same value locally in temp), then the first assigns a new value to i (say, from 1 to 6) and the other one does the same thing (from 1 to 6).

The synchronization must span from reading to assigning a value. Your first synchronization has no effect (reading an int is atomic) and the second as well. In my opinion, these are the correct forms:

void synchronized incIBy5() {
  i += 5 
}

void incIBy5() {
  synchronized(this) {
    i += 5 
  }
}

void incIBy5() {
  synchronized(this) {
    int temp = i;
    i = temp + 5;
  }
}

What is the correct "-moz-appearance" value to hide dropdown arrow of a <select> element

To get rid of the default dropdown arrow use:

-moz-appearance: window; 

How to wrap text in textview in Android

Just set layout_with to a definate size, when the text fills the maximum width it will overflow to the next line causing a wrap effect.

<TextView
    android:id="@+id/segmentText"
    android:layout_marginTop="10dp"
    android:layout_below="@+id/segmentHeader"
    android:text="You have the option to record in one go or segments(if you swap options 
    you will loose your current recordings)"
    android:layout_width="300dp"
    android:layout_height="wrap_content"/>

How to run Gradle from the command line on Mac bash

./gradlew

Your directory with gradlew is not included in the PATH, so you must specify path to the gradlew. . means "current directory".

System.Net.WebException: The operation has timed out

I'm not sure about your first code sample where you use WebClient.UploadValues, it's not really enough to go on, could you paste more of your surrounding code? Regarding your WebRequest code, there are two things at play here:

  1. You're only requesting the headers of the response**, you never read the body of the response by opening and reading (to its end) the ResponseStream. Because of this, the WebRequest client helpfully leaves the connection open, expecting you to request the body at any moment. Until you either read the response body to completion (which will automatically close the stream for you), clean up and close the stream (or the WebRequest instance) or wait for the GC to do its thing, your connection will remain open.

  2. You have a default maximum amount of active connections to the same host of 2. This means you use up your first two connections and then never dispose of them so your client isn't given the chance to complete the next request before it reaches its timeout (which is milliseconds, btw, so you've set it to 0.2 seconds - the default should be fine).

If you don't want the body of the response (or you've just uploaded or POSTed something and aren't expecting a response), simply close the stream, or the client, which will close the stream for you.

The easiest way to fix this is to make sure you use using blocks on disposable objects:

for (int i = 0; i < ops1; i++)
{
    Uri myUri = new Uri(site);
    WebRequest myWebRequest = WebRequest.Create(myUri);
    //myWebRequest.Timeout = 200;
    using (WebResponse myWebResponse = myWebRequest.GetResponse())
    {
        // Do what you want with myWebResponse.Headers.
    } // Your response will be disposed of here
}

Another solution is to allow 200 concurrent connections to the same host. However, unless you're planning to multi-thread this operation so you'd need multiple, concurrent connections, this won't really help you:

 ServicePointManager.DefaultConnectionLimit = 200;

When you're getting timeouts within code, the best thing to do is try to recreate that timeout outside of your code. If you can't, the problem probably lies with your code. I usually use cURL for that, or just a web browser if it's a simple GET request.

** In reality, you're actually requesting the first chunk of data from the response, which contains the HTTP headers, and also the start of the body. This is why it's possible to read HTTP header info (such as Content-Encoding, Set-Cookie etc) before reading from the output stream. As you read the stream, further data is retrieved from the server. WebRequest's connection to the server is kept open until you reach the end of this stream (effectively closing it as it's not seekable), manually close it yourself or it is disposed of. There's more about this here.

How to add image in a TextView text?

fun TextView.addImage(atText: String, @DrawableRes imgSrc: Int, imgWidth: Int, imgHeight: Int) {
    val ssb = SpannableStringBuilder(this.text)

    val drawable = ContextCompat.getDrawable(this.context, imgSrc) ?: return
    drawable.mutate()
    drawable.setBounds(0, 0,
            imgWidth,
            imgHeight)
    val start = text.indexOf(atText)
    ssb.setSpan(VerticalImageSpan(drawable), start, start + atText.length, Spannable.SPAN_INCLUSIVE_EXCLUSIVE)
    this.setText(ssb, TextView.BufferType.SPANNABLE)
}

VerticalImageSpan class from great answer https://stackoverflow.com/a/38788432/5381331

Using

val textView = findViewById<TextView>(R.id.textview)
textView.setText("Send an [email-icon] to [email protected].")
textView.addImage("[email-icon]", R.drawable.ic_email,
        resources.getDimensionPixelOffset(R.dimen.dp_30),
        resources.getDimensionPixelOffset(R.dimen.dp_30))

Result

Note
Why VerticalImageSpan class?
ImageSpan.ALIGN_CENTER attribute requires API 29.
Also, after the test, I see that ImageSpan.ALIGN_CENTER only work if the image smaller than the text, if the image bigger than the text then only image is in center, text not center, it align on bottom of image

pip install mysql-python fails with EnvironmentError: mysql_config not found

For Linux

this works for me

yum install python-devel mysql-devel

How to serve all existing static files directly with NGINX, but proxy the rest to a backend server.

Try this:

location / {
    root /path/to/root;
    expires 30d;
    access_log off;
}

location ~* ^.*\.php$ {
    if (!-f $request_filename) {
        return 404;
    }
    proxy_set_header X-Real-IP  $remote_addr;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass http://127.0.0.1:8080;
}

Hopefully it works. Regular expressions have higher priority than plain strings, so all requests ending in .php should be forwared to Apache if only a corresponding .php file exists. Rest will be handled as static files. The actual algorithm of evaluating location is here.

Python + Django page redirect

You can do this in the Admin section. It's explained in the documentation.

https://docs.djangoproject.com/en/dev/ref/contrib/redirects/

jQuery click event not working after adding class

Based on @Arun P Johny this is how you do it for an input:

<input type="button" class="btEdit" id="myButton1">

This is how I got it in jQuery:

$(document).on('click', "input.btEdit", function () {
    var id = this.id;
    console.log(id);
});

This will log on the console: myButton1. As @Arun said you need to add the event dinamically, but in my case you don't need to call the parent first.

UPDATE

Though it would be better to say:

$(document).on('click', "input.btEdit", function () {
    var id = $(this).id;
    console.log(id);
});

Since this is JQuery's syntax, even though both will work.

Run jar file with command line arguments

For the question

How can i run a jar file in command prompt but with arguments

.

To pass arguments to the jar file at the time of execution

java -jar myjar.jar arg1 arg2

In the main() method of "Main-Class" [mentioned in the manifest.mft file]of your JAR file. you can retrieve them like this:

String arg1 = args[0];
String arg2 = args[1];

How can I extract a good quality JPEG image from a video file with ffmpeg?

Output the images in a lossless format such as PNG:

ffmpeg.exe -i 10fps.h264 -r 10 -f image2 10fps.h264_%03d.png

Edit/Update: Not quite sure why I originally gave a strange filename example (with a possibly made-up extension).

I have since found that -vsync 0 is simpler than -r 10 because it avoids needing to know the frame rate.

This is something like what I currently use:

mkdir stills
ffmpeg -i my-film.mp4 -vsync 0 -f image2 stills/my-film-%06d.png

To extract only the key frames (which are likely to be of higher quality post-edit):

ffmpeg -skip_frame nokey -i my-film.mp4 -vsync 0 -f image2 stills/my-film-%06d.png

Then use another program (where you can more precisely specify quality, subsampling and DCT method – e.g. GIMP) to convert the PNGs you want to JPEG.

It is possible to obtain slightly sharper images in JPEG format this way than is possible with -qmin 1 -q:v 1 and outputting as JPEG directly from ffmpeg.

nginx missing sites-available directory

Well, I think nginx by itself doesn't have that in its setup, because the Ubuntu-maintained package does it as a convention to imitate Debian's apache setup. You could create it yourself if you wanted to emulate the same setup.

Create /etc/nginx/sites-available and /etc/nginx/sites-enabled and then edit the http block inside /etc/nginx/nginx.conf and add this line

include /etc/nginx/sites-enabled/*;

Of course, all the files will be inside sites-available, and you'd create a symlink for them inside sites-enabled for those you want enabled.

.NET NewtonSoft JSON deserialize map to a different property name

Expanding Rentering.com's answer, in scenarios where a whole graph of many types is to be taken care of, and you're looking for a strongly typed solution, this class can help, see usage (fluent) below. It operates as either a black-list or white-list per type. A type cannot be both (Gist - also contains global ignore list).

public class PropertyFilterResolver : DefaultContractResolver
{
  const string _Err = "A type can be either in the include list or the ignore list.";
  Dictionary<Type, IEnumerable<string>> _IgnorePropertiesMap = new Dictionary<Type, IEnumerable<string>>();
  Dictionary<Type, IEnumerable<string>> _IncludePropertiesMap = new Dictionary<Type, IEnumerable<string>>();
  public PropertyFilterResolver SetIgnoredProperties<T>(params Expression<Func<T, object>>[] propertyAccessors)
  {
    if (propertyAccessors == null) return this;

    if (_IncludePropertiesMap.ContainsKey(typeof(T))) throw new ArgumentException(_Err);

    var properties = propertyAccessors.Select(GetPropertyName);
    _IgnorePropertiesMap[typeof(T)] = properties.ToArray();
    return this;
  }

  public PropertyFilterResolver SetIncludedProperties<T>(params Expression<Func<T, object>>[] propertyAccessors)
  {
    if (propertyAccessors == null)
      return this;

    if (_IgnorePropertiesMap.ContainsKey(typeof(T))) throw new ArgumentException(_Err);

    var properties = propertyAccessors.Select(GetPropertyName);
    _IncludePropertiesMap[typeof(T)] = properties.ToArray();
    return this;
  }

  protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
  {
    var properties = base.CreateProperties(type, memberSerialization);

    var isIgnoreList = _IgnorePropertiesMap.TryGetValue(type, out IEnumerable<string> map);
    if (!isIgnoreList && !_IncludePropertiesMap.TryGetValue(type, out map))
      return properties;

    Func<JsonProperty, bool> predicate = jp => map.Contains(jp.PropertyName) == !isIgnoreList;
    return properties.Where(predicate).ToArray();
  }

  string GetPropertyName<TSource, TProperty>(
  Expression<Func<TSource, TProperty>> propertyLambda)
  {
    if (!(propertyLambda.Body is MemberExpression member))
      throw new ArgumentException($"Expression '{propertyLambda}' refers to a method, not a property.");

    if (!(member.Member is PropertyInfo propInfo))
      throw new ArgumentException($"Expression '{propertyLambda}' refers to a field, not a property.");

    var type = typeof(TSource);
    if (!type.GetTypeInfo().IsAssignableFrom(propInfo.DeclaringType.GetTypeInfo()))
      throw new ArgumentException($"Expresion '{propertyLambda}' refers to a property that is not from type '{type}'.");

    return propInfo.Name;
  }
}

Usage:

var resolver = new PropertyFilterResolver()
  .SetIncludedProperties<User>(
    u => u.Id, 
    u => u.UnitId)
  .SetIgnoredProperties<Person>(
    r => r.Responders)
  .SetIncludedProperties<Blog>(
    b => b.Id)
  .Ignore(nameof(IChangeTracking.IsChanged)); //see gist

Why is access to the path denied?

According to File.Delete Method...

An UnauthorizedAccessException means one of 4 things:

  • The caller does not have the required permission.
  • The file is an executable file that is in use.
  • Path is a directory.
  • Path specified a read-only file.

Hibernate Criteria for Dates

try this,

    String dateStr = "17-April-2011 19:20:23.707000000 ";
    Date dateForm = new SimpleDateFormat("dd-MMMM-yyyy HH:mm:ss").parse(dateStr);
    SimpleDateFormat format = new SimpleDateFormat("dd-MM-yyyy");  

    String newDate = format.format(dateForm);  

    Calendar today = Calendar.getInstance();
    Date fromDate = format.parse(newDate);
    today.setTime(fromDate);
    today.add(Calendar.DAY_OF_YEAR, 1);
    Date toDate= new SimpleDateFormat("dd-MM-yyyy").parse(format.format(today.getTime()));

    Criteria crit = sessionFactory.getCurrentSession().createCriteria(Model.class);
    crit.add(Restrictions.ge("dateFieldName", fromDate));
    crit.add(Restrictions.le("dateFieldName", toDate));
    return crit.list();

Java ElasticSearch None of the configured nodes are available

Check the ES server logs

sudo tail -f /var/log/elasticsearch/elasticsearch.log

I was using an outdated client

Received message from unsupported version: [5.0.0] minimal compatible version is: [6.8.0]

How can I get the length of text entered in a textbox using jQuery?

You need to only grab the element with an appropriate jQuery selector and then the .val() method to get the string contained in the input textbox and then call the .length on that string.

$('input:text').val().length

However, be warned that if the selector matches multiple inputs, .val() will only return the value of the first textbox. You can also change the selector to get a more specific element but keep the :text to ensure it's an input textbox.

On another note, to get the length of a string contained in another, non-input element, you can use the .text() function to get the string and then use .length on that string to find its length.

How can I get jQuery to perform a synchronous, rather than asynchronous, Ajax request?

This is example:

$.ajax({
  url: "test.html",
  async: false
}).done(function(data) {
   // Todo something..
}).fail(function(xhr)  {
   // Todo something..
});

nodejs get file name from absolute path?

So Nodejs comes with the default global variable called '__fileName' that holds the current file being executed My advice is to pass the __fileName to a service from any file , so that the retrieval of the fileName is made dynamic

Below, I make use of the fileName string and then split it based on the path.sep. Note path.sep avoids issues with posix file seperators and windows file seperators (issues with '/' and '\'). It is much cleaner. Getting the substring and getting only the last seperated name and subtracting it with the actulal length by 3 speaks for itself.

You can write a service like this (Note this is in typescript , but you can very well write it in js )

export class AppLoggingConstants {

    constructor(){

    }
      // Here make sure the fileName param is actually '__fileName'
    getDefaultMedata(fileName: string, methodName: string) {
        const appName = APP_NAME;
        const actualFileName = fileName.substring(fileName.lastIndexOf(path.sep)+1, fileName.length - 3);
        //const actualFileName = fileName;
     return appName+ ' -- '+actualFileName;
    }


}

export const AppLoggingConstantsInstance = new AppLoggingConstants();

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

Your team's advice is almost right, except for the mistake that was made. Once you find out why, you will never forget it. Take a look at this mistake.

/^(7|8|9)\d{9}$/

What this does:

  • ^ and $ denotes anchored matches, which asserts that the subpattern in between these anchors are the entire match. The string will only match if the subpattern matches the entirety of it, not just a section.
  • () denotes a capturing group.
  • 7|8|9 denotes matching either of 7, 8, or 9. It does this with alternations, which is what the pipe operator | does — alternating between alternations. This backtracks between alternations: If the first alternation is not matched, the engine has to return before the pointer location moved during the match of the alternation, to continue matching the next alternation; Whereas the character class can advance sequentially. See this match on a regex engine with optimizations disabled:
Pattern: (r|f)at
Match string: carat

alternations

Pattern: [rf]at
Match string: carat

class

  • \d{9} matches nine digits. \d is a shorthanded metacharacter, which matches any digits.
/^[7|8|9][\d]{9}$/

Look at what it does:

  • ^ and $ denotes anchored matches as well.
  • [7|8|9] is a character class. Any characters from the list 7, |, 8, |, or 9 can be matched, thus the | was added in incorrectly. This matches without backtracking.
  • [\d] is a character class that inhabits the metacharacter \d. The combination of the use of a character class and a single metacharacter is a bad idea, by the way, since the layer of abstraction can slow down the match, but this is only an implementation detail and only applies to a few of regex implementations. JavaScript is not one, but it does make the subpattern slightly longer.
  • {9} indicates the previous single construct is repeated nine times in total.

The optimal regex is /^[789]\d{9}$/, because /^(7|8|9)\d{9}$/ captures unnecessarily which imposes a performance decrease on most regex implementations ( happens to be one, considering the question uses keyword var in code, this probably is JavaScript). The use of which runs on PCRE for preg matching will optimize away the lack of backtracking, however we're not in PHP either, so using classes [] instead of alternations | gives performance bonus as the match does not backtrack, and therefore both matches and fails faster than using your previous regular expression.

Can I start the iPhone simulator without "Build and Run"?

The easiest way is start the simulator from the Xcode, and then on the dock, Ctrl + Click on the icon and select Keep in Dockenter image description here

How to put space character into a string name in XML?

As already mentioned the correct way to have a space in an XML file is by using \u0020 which is the unicode character for a space.

Example:

<string name="spelatonertext3">-4,\u00205,\u0020-5,\u00206,\u0020-6</string>

Other suggestions have said to use &#160; or &#032; but there is two downsides to this. The first downside is that these are ASCII characters so you are relying on something like a TextView to parse them. The second downside is that &#160; can sometimes cause strange wrapping in TextViews.

How to verify a Text present in the loaded page through WebDriver

If you want check only displayed objects(C#):

    public bool TextPresent(string text, int expectedNumberOfOccurrences)
    {
        var elements = Driver.FindElements(By.XPath(".//*[text()[contains(.,'" + text + "')]]"));
        var dispayedElements = 0;
        foreach (var webElement in elements)
        {
            if (webElement.Displayed)
            {
                dispayedElements++;
            }
        }
        var allExpectedElementsDisplayed = dispayedElements == expectedNumberOfOccurrences;
        return allExpectedElementsDisplayed;
    }

Conditional formatting using AND() function

Same issues as others reported - using Excel 2016. Found that when applying conditional formulas against tables; AND, multiplying the conditions, and adding the conditions failed. Had to create the TRUE/FALSE logic myself:

=IF($C2="SomeText",0,1)+IF(INT($D2)>1000,0,1)=0

Is there anyway to exclude artifacts inherited from a parent POM?

When you call a package but do not want some of its dependencies you can do a thing like this (in this case I did not want the old log4j to be added because I needed to use the newer one):

<dependency>
  <groupId>package</groupId>
  <artifactId>package-pk</artifactId>
  <version>${package-pk.version}</version>

  <exclusions>
    <exclusion>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
    </exclusion>
    <exclusion>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
    </exclusion>
  </exclusions>
</dependency>

<!-- LOG4J -->
<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j-core</artifactId>
  <version>2.5</version>
</dependency>
<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j-api</artifactId>
  <version>2.5</version>
</dependency>

This works for me... but I am pretty new to java/maven so it is maybe not optimum.

What __init__ and self do in Python?

In this code:

class A(object):
    def __init__(self):
        self.x = 'Hello'

    def method_a(self, foo):
        print self.x + ' ' + foo

... the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidden parameter to the methods defined on an object; Python does not. You have to declare it explicitly. When you create an instance of the A class and call its methods, it will be passed automatically, as in ...

a = A()               # We do not pass any argument to the __init__ method
a.method_a('Sailor!') # We only pass a single argument

The __init__ method is roughly what represents a constructor in Python. When you call A() Python creates an object for you, and passes it as the first parameter to the __init__ method. Any additional parameters (e.g., A(24, 'Hello')) will also get passed as arguments--in this case causing an exception to be raised, since the constructor isn't expecting them.

Build not visible in itunes connect

Check all the key and values in info.plist file. if any key is missing then it will cause this issue. AppIcon and other thing written in info.plist file must be prefect then u will not able to get this issue.

Changing java platform on which netbeans runs

Fix this by moving my jdk folder to other disk

How to send an email with Python?

I recommend that you use the standard packages email and smtplib together to send email. Please look at the following example (reproduced from the Python documentation). Notice that if you follow this approach, the "simple" task is indeed simple, and the more complex tasks (like attaching binary objects or sending plain/HTML multipart messages) are accomplished very rapidly.

# Import smtplib for the actual sending function
import smtplib

# Import the email modules we'll need
from email.mime.text import MIMEText

# Open a plain text file for reading.  For this example, assume that
# the text file contains only ASCII characters.
with open(textfile, 'rb') as fp:
    # Create a text/plain message
    msg = MIMEText(fp.read())

# me == the sender's email address
# you == the recipient's email address
msg['Subject'] = 'The contents of %s' % textfile
msg['From'] = me
msg['To'] = you

# Send the message via our own SMTP server, but don't include the
# envelope header.
s = smtplib.SMTP('localhost')
s.sendmail(me, [you], msg.as_string())
s.quit()

For sending email to multiple destinations, you can also follow the example in the Python documentation:

# Import smtplib for the actual sending function
import smtplib

# Here are the email package modules we'll need
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart

# Create the container (outer) email message.
msg = MIMEMultipart()
msg['Subject'] = 'Our family reunion'
# me == the sender's email address
# family = the list of all recipients' email addresses
msg['From'] = me
msg['To'] = ', '.join(family)
msg.preamble = 'Our family reunion'

# Assume we know that the image files are all in PNG format
for file in pngfiles:
    # Open the files in binary mode.  Let the MIMEImage class automatically
    # guess the specific image type.
    with open(file, 'rb') as fp:
        img = MIMEImage(fp.read())
    msg.attach(img)

# Send the email via our own SMTP server.
s = smtplib.SMTP('localhost')
s.sendmail(me, family, msg.as_string())
s.quit()

As you can see, the header To in the MIMEText object must be a string consisting of email addresses separated by commas. On the other hand, the second argument to the sendmail function must be a list of strings (each string is an email address).

So, if you have three email addresses: [email protected], [email protected], and [email protected], you can do as follows (obvious sections omitted):

to = ["[email protected]", "[email protected]", "[email protected]"]
msg['To'] = ",".join(to)
s.sendmail(me, to, msg.as_string())

the ",".join(to) part makes a single string out of the list, separated by commas.

From your questions I gather that you have not gone through the Python tutorial - it is a MUST if you want to get anywhere in Python - the documentation is mostly excellent for the standard library.

mysql select from n last rows

Might be a very late answer, but this is good and simple.

select * from table_name order by id desc limit 5

This query will return a set of last 5 values(last 5 rows) you 've inserted in your table

NameError: global name 'unicode' is not defined - in Python 3

You can use the six library to support both Python 2 and 3:

import six
if isinstance(value, six.string_types):
    handle_string(value)

What's the point of the X-Requested-With header?

Make sure you read SilverlightFox's answer. It highlights a more important reason.

The reason is mostly that if you know the source of a request you may want to customize it a little bit.

For instance lets say you have a website which has many recipes. And you use a custom jQuery framework to slide recipes into a container based on a link they click. The link may be www.example.com/recipe/apple_pie

Now normally that returns a full page, header, footer, recipe content and ads. But if someone is browsing your website some of those parts are already loaded. So you can use an AJAX to get the recipe the user has selected but to save time and bandwidth don't load the header/footer/ads.

Now you can just write a secondary endpoint for the data like www.example.com/recipe_only/apple_pie but that's harder to maintain and share to other people.

But it's easier to just detect that it is an ajax request making the request and then returning only a part of the data. That way the user wastes less bandwidth and the site appears more responsive.

The frameworks just add the header because some may find it useful to keep track of which requests are ajax and which are not. But it's entirely dependent on the developer to use such techniques.

It's actually kind of similar to the Accept-Language header. A browser can request a website please show me a Russian version of this website without having to insert /ru/ or similar in the URL.

Get the current time in C

Initialize your now variable.

time_t now = time(0); // Get the system time

The localtime function is used to convert the time value in the passed time_t to a struct tm, it doesn't actually retrieve the system time.

CRON job to run on the last day of the month

Set up a cron job to run on the first day of the month. Then change the system's clock to be one day ahead.

Should each and every table have a primary key?

I always have a primary key, even if in the beginning I don't have a purpose in mind yet for it. There have been a few times when I eventually need a PK in a table that doesn't have one and it's always more trouble to put it in later. I think there is more of an upside to always including one.

How to read all rows from huge table?

I did it like below. Not the best way i think, but it works :)

    Connection c = DriverManager.getConnection("jdbc:postgresql://....");
    PreparedStatement s = c.prepareStatement("select * from " + tabName + " where id > ? order by id");
    s.setMaxRows(100);
    int lastId = 0;
    for (;;) {
        s.setInt(1, lastId);
        ResultSet rs = s.executeQuery();

        int lastIdBefore = lastId;
        while (rs.next()) {
            lastId = Integer.parseInt(rs.getObject(1).toString());
            // ...
        }

        if (lastIdBefore == lastId) {
            break;
        }
    }

How to check task status in Celery?

Apart from above Programmatic approach Using Flower Task status can be easily seen.

Real-time monitoring using Celery Events. Flower is a web based tool for monitoring and administrating Celery clusters.

  1. Task progress and history
  2. Ability to show task details (arguments, start time, runtime, and more)
  3. Graphs and statistics

Official Document: Flower - Celery monitoring tool

Installation:

$ pip install flower

Usage:

http://localhost:5555

How to add a custom right-click menu to a webpage?

Answering your question - use contextmenu event, like below:

_x000D_
_x000D_
if (document.addEventListener) {_x000D_
  document.addEventListener('contextmenu', function(e) {_x000D_
    alert("You've tried to open context menu"); //here you draw your own menu_x000D_
    e.preventDefault();_x000D_
  }, false);_x000D_
} else {_x000D_
  document.attachEvent('oncontextmenu', function() {_x000D_
    alert("You've tried to open context menu");_x000D_
    window.event.returnValue = false;_x000D_
  });_x000D_
}
_x000D_
<body>_x000D_
  Lorem ipsum..._x000D_
</body>
_x000D_
_x000D_
_x000D_

But you should ask yourself, do you really want to overwrite default right-click behavior - it depends on application that you're developing.


JSFIDDLE

Set element width or height in Standards Mode

The style property lets you specify values for CSS properties.

The CSS width property takes a length as its value.

Lengths require units. In quirks mode, browsers tend to assume pixels if provided with an integer instead of a length. Specify units.

e1.style.width = "400px";

Difference between single and double quotes in Bash

If you're referring to what happens when you echo something, the single quotes will literally echo what you have between them, while the double quotes will evaluate variables between them and output the value of the variable.

For example, this

#!/bin/sh
MYVAR=sometext
echo "double quotes gives you $MYVAR"
echo 'single quotes gives you $MYVAR'

will give this:

double quotes gives you sometext
single quotes gives you $MYVAR

How do I check for vowels in JavaScript?

Personally, I would define it this way:

function isVowel( chr ){ return 'aeiou'.indexOf( chr[0].toLowerCase() ) !== -1 }

You could also use ['a','e','i','o','u'] and skip the length test, but then you are creating an array each time you call the function. (There are ways of mimicking this via closures, but those are a bit obscure to read)

Git add all subdirectories

Also struggled, but got it right typing

git add -f ./JS/*

where JS was my folder name which contain sub folders and files

vertical & horizontal lines in matplotlib

This may be a common problem for new users of Matplotlib to draw vertical and horizontal lines. In order to understand this problem, you should be aware that different coordinate systems exist in Matplotlib.

The method axhline and axvline are used to draw lines at the axes coordinate. In this coordinate system, coordinate for the bottom left point is (0,0), while the coordinate for the top right point is (1,1), regardless of the data range of your plot. Both the parameter xmin and xmax are in the range [0,1].

On the other hand, method hlines and vlines are used to draw lines at the data coordinate. The range for xmin and xmax are the in the range of data limit of x axis.

Let's take a concrete example,

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 5, 100)
y = np.sin(x)

fig, ax = plt.subplots()

ax.plot(x, y)
ax.axhline(y=0.5, xmin=0.0, xmax=1.0, color='r')
ax.hlines(y=0.6, xmin=0.0, xmax=1.0, color='b')

plt.show()

It will produce the following plot: enter image description here

The value for xmin and xmax are the same for the axhline and hlines method. But the length of produced line is different.

adb devices command not working

Every answer I've read indicates the SUBSYSTEM=="usb". However, my (perhaps ancient) udev needed this to be changed to DRIVER=="usb". At last I can run the adb server as a non-root user... yay.

It can be instructive to look at the output of udevmonitor --env, followed by the output of

udevinfo -a -p <DEVICE_PATH_AS_REPORTED_BY-udevmonitor>

Calculate compass bearing / heading to location in Android

If you are on the same timezone

Convert GPS to UTM

http://www.ibm.com/developerworks/java/library/j-coordconvert/ http://stackoverflow.com/questions/176137/java-convert-lat-lon-to-utm

UTM coordinates get you a simples X Y 2D

Calculate the angle between both UTM locations

http://forums.groundspeak.com/GC/index.php?showtopic=146917

This gives the direction as if you were looking north

So whatever you rotate related do North just subtract this angle

If both point have a UTM 45º degree angle and you are 5º east of north, your arrow will point to 40º of north

How to select the first element with a specific attribute using XPath

for ex.

<input b="demo">

And

(input[@b='demo'])[1]

OnItemClickListener using ArrayAdapter for ListView

Use OnItemClickListener

   ListView lv = getListView();
   lv.setOnItemClickListener(new OnItemClickListener()
   {
      @Override
      public void onItemClick(AdapterView<?> adapter, View v, int position,
            long arg3) 
      {
            String value = (String)adapter.getItemAtPosition(position); 
            // assuming string and if you want to get the value on click of list item
            // do what you intend to do on click of listview row
      }
   });

When you click on a row a listener is fired. So you setOnClickListener on the listview and use the annonymous inner class OnItemClickListener.

You also override onItemClick. The first param is a adapter. Second param is the view. third param is the position ( index of listview items).

Using the position you get the item .

Edit : From your comments i assume you need to set the adapter o listview

So assuming your activity extends ListActivtiy

     setListAdapter(adapter); 

Or if your activity class extends Activity

     ListView lv = (ListView) findViewById(R.id.listview1);
     //initialize adapter 
     lv.setAdapter(adapter); 

How to open a file for both reading and writing?

r+ is the canonical mode for reading and writing at the same time. This is not different from using the fopen() system call since file() / open() is just a tiny wrapper around this operating system call.

Opening a .ipynb.txt File

go to cmd get into file directory and type jupyter notebook filename.ipynb in my case it open code editor and provide local host connection string copy that string and paste in any browser!done

How do I uniquely identify computers visiting my web site?

Assuming you don't want the user to be in control, you can't. The web doesn't work like that, the best you can hope for is some heuristics.

If it is an option to force your visitor to install some software and use TCPA you may be able to pull something off.

Asynchronous vs synchronous execution, what does it really mean?

I created a gif for explain this, hope to be helpful: look, line 3 is asynchronous and others are synchronous. all lines before line 3 should wait until before line finish its work, but because of line 3 is asynchronous, next line (line 4), don't wait for line 3, but line 5 should wait for line 4 to finish its work, and line 6 should wait for line 5 and 7 for 6, because line 4,5,6,7 are not asynchronous. line 3 is asynchronous and others are synchronous

Python: How to get values of an array at certain index positions?

The one liner "no imports" version

a = [0,88,26,3,48,85,65,16,97,83,91]
ind_pos = [1,5,7]
[ a[i] for i in ind_pos ]

Touch move getting stuck Ignored attempt to cancel a touchmove

The event must be cancelable. Adding an if statement solves this issue.

if (e.cancelable) {
   e.preventDefault();
}

In your code you should put it here:

if (this.isSwipe(swipeThreshold) && e.cancelable) {
   e.preventDefault();
   e.stopPropagation();
   swiping = true;
}

How to always show the vertical scrollbar in a browser?

Tried to do the solution with:

body {
  overflow-y: scroll;
}

But I ended up with two scrollbars in Firefox in this case. So I recommend to use it on the html element like this:

html {
  overflow-y: scroll;
}

Ruby's File.open gives "No such file or directory - text.txt (Errno::ENOENT)" error

Please use chomp() or chomp() with STDIN

i.e. test1.rb

print 'Enter File name: '

fname = STDIN.gets.chomp()  # or fname = gets.chomp()


fname_read = File.open(fname)

puts fname_read.read()

How to suppress binary file matching results in grep

There are three options, that you can use. -I is to exclude binary files in grep. Other are for line numbers and file names.

grep -I -n -H 


-I -- process a binary file as if it did not contain matching data; 
-n -- prefix each line of output with the 1-based line number within its input file
-H -- print the file name for each match

So this might be a way to run grep:

grep -InH your-word *

jQuery selector to get form by name

For detecting if the form is present, I'm using

if($('form[name="frmSave"]').length > 0) {
    //do something
}

Check if a string isn't nil or empty in Lua

Can this code be simplified in one if test instead two?

nil and '' are different values. If you need to test that s is neither, IMO you should just compare against both, because it makes your intent the most clear.

That and a few alternatives, with their generated bytecode:

if not foo or foo == '' then end
     GETGLOBAL       0 -1    ; foo
     TEST            0 0 0
     JMP             3       ; to 7
     GETGLOBAL       0 -1    ; foo
     EQ              0 0 -2  ; - ""
     JMP             0       ; to 7

if foo == nil or foo == '' then end
    GETGLOBAL       0 -1    ; foo
    EQ              1 0 -2  ; - nil
    JMP             3       ; to 7
    GETGLOBAL       0 -1    ; foo
    EQ              0 0 -3  ; - ""
    JMP             0       ; to 7

if (foo or '') == '' then end
   GETGLOBAL       0 -1    ; foo
   TEST            0 0 1
   JMP             1       ; to 5
   LOADK           0 -2    ; ""
   EQ              0 0 -2  ; - ""
   JMP             0       ; to 7

The second is fastest in Lua 5.1 and 5.2 (on my machine anyway), but difference is tiny. I'd go with the first for clarity's sake.

How to compile multiple java source files in command line

or you can use the following to compile the all java source files in current directory..

javac *.java

Regular Expression for matching parentheses

For any special characters you should use '\'. So, for matching parentheses - /\(/

Is there a way to @Autowire a bean that requires constructor arguments?

You can also configure your component like this :

package mypackage;
import org.springframework.context.annotation.Configuration;
   @Configuration
   public class MyConstructorClassConfig {


   @Bean
   public MyConstructorClass myConstructorClass(){
      return new myConstructorClass("foobar");
   }
  }
}

With the Bean annotation, you are telling Spring to register the returned bean in the BeanFactory.

So you can autowire it as you wish.

How can I get dictionary key as variable directly in Python (not by searching from value)?

You should iterate over keys with:

for key in mydictionary:
   print "key: %s , value: %s" % (key, mydictionary[key])

EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType

In my case I had inherited from the IdentityDbContext correctly (with my own custom types and key defined) but had inadvertantly removed the call to the base class's OnModelCreating:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder); // I had removed this
    /// Rest of on model creating here.
}

Which then fixed up my missing indexes from the identity classes and I could then generate migrations and enable migrations appropriately.

MySQL Database won't start in XAMPP Manager-osx

Check the "/Applications/XAMPP/xamppfiles/var/mysql" file's owner.

If you see different user and group instead of "_mysql".

sudo chown -R _mysql:_mysql mysql

Download file from web in Python 3

from urllib import request

def get(url):
    with request.urlopen(url) as r:
        return r.read()


def download(url, file=None):
    if not file:
        file = url.split('/')[-1]
    with open(file, 'wb') as f:
        f.write(get(url))

How to get twitter bootstrap modal to close (after initial launch)

I had the same problem in the iphone or desktop, didnt manage to close the dialog when pressing the close button.

i found out that The <button> tag defines a clickable button and is needed to specify the type attribute for a element as follow:

<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>

check the example code for bootstrap modals at : BootStrap javascript Page

Highlight all occurrence of a selected word?

I know than it's a really old question, but if someone is interested in this feature, can check this code http://vim.wikia.com/wiki/Auto_highlight_current_word_when_idle

" Highlight all instances of word under cursor, when idle.
" Useful when studying strange source code.
" Type z/ to toggle highlighting on/off.
nnoremap z/ :if AutoHighlightToggle()<Bar>set hls<Bar>endif<CR>
function! AutoHighlightToggle()
   let @/ = ''
   if exists('#auto_highlight')
     au! auto_highlight
     augroup! auto_highlight
     setl updatetime=4000
     echo 'Highlight current word: off'
     return 0
  else
    augroup auto_highlight
    au!
    au CursorHold * let @/ = '\V\<'.escape(expand('<cword>'), '\').'\>'
    augroup end
    setl updatetime=500
    echo 'Highlight current word: ON'
  return 1
 endif
endfunction

Recover from git reset --hard?

The information is lost.

Since you did not commit, your .git never stored this information. So, basically git cannot recover it for you.

But, If you just did git diff, there is a way you can recover using the terminal output with the following 3 simple steps.

  1. scroll your terminal and look for the o/p of git diff. Save the o/p in a file called diff.patch
  2. Search & Replace all 7 spaces and 8 spaces with tab(\t) character and save the changes.
  3. Go into your git repository. Apply the diff.patch (patch -p1 < diff.patch)

You are saved! :)

Note : While you are copying the data from terminal to a file, be careful and clearly see that the data is continuous output and did not contain any redundant data(due to pressing up and down arrows). Otherwise you might mess it up.

How to concatenate items in a list to a single string?

If you have mixed content list. And want to stringify it. Here is one way:

Consider this list:

>>> aa
[None, 10, 'hello']

Convert it to string:

>>> st = ', '.join(map(str, map(lambda x: f'"{x}"' if isinstance(x, str) else x, aa)))
>>> st = '[' + st + ']'
>>> st
'[None, 10, "hello"]'

If required, convert back to list:

>>> ast.literal_eval(st)
[None, 10, 'hello']

How to check whether a string contains a substring in Ruby

You can use the String Element Reference method which is []

Inside the [] can either be a literal substring, an index, or a regex:

> s='abcdefg'
=> "abcdefg"
> s['a']
=> "a"
> s['z']
=> nil

Since nil is functionally the same as false and any substring returned from [] is true you can use the logic as if you use the method .include?:

0> if s[sub_s]
1>    puts "\"#{s}\" has \"#{sub_s}\""
1> else 
1*    puts "\"#{s}\" does not have \"#{sub_s}\""
1> end
"abcdefg" has "abc"

0> if s[sub_s]
1>    puts "\"#{s}\" has \"#{sub_s}\""
1> else 
1*    puts "\"#{s}\" does not have \"#{sub_s}\""
1> end
"abcdefg" does not have "xyz" 

Just make sure you don't confuse an index with a sub string:

> '123456790'[8]    # integer is eighth element, or '0'
=> "0"              # would test as 'true' in Ruby
> '123456790'['8']  
=> nil              # correct

You can also use a regex:

> s[/A/i]
=> "a"
> s[/A/]
=> nil

How to subtract X day from a Date object in Java?

With Java 8 it's really simple now:

 LocalDate date = LocalDate.now().minusDays(300);

A great guide to the new api can be found here.

Enabling the OpenSSL in XAMPP

Yes, you must open php.ini and remove the semicolon to:

;extension=php_openssl.dll

If you don't have that line, check that you have the file (In my PC is on D:\xampp\php\ext) and add this to php.ini in the "Dynamic Extensions" section:

extension=php_openssl.dll

Things have changed for PHP > 7. This is what i had to do for PHP 7.2.

Step: 1: Uncomment extension=openssl

Step: 2: Uncomment extension_dir = "ext"

Step: 3: Restart xampp.

Done.

Explanation: ( From php.ini )

If you wish to have an extension loaded automatically, use the following syntax:

extension=modulename

Note : The syntax used in previous PHP versions (extension=<ext>.so and extension='php_<ext>.dll) is supported for legacy reasons and may be deprecated in a future PHP major version. So, when it is possible, please move to the new (extension=<ext>) syntax.

Special Note: Be sure to appropriately set the extension_dir directive.

Passing additional variables from command line to make

The simplest way is:

make foo=bar target

Then in your makefile you can refer to $(foo). Note that this won't propagate to sub-makes automatically.

If you are using sub-makes, see this article: Communicating Variables to a Sub-make

When to use React setState callback

Consider setState call

this.setState({ counter: this.state.counter + 1 })

IDEA

setState may be called in async function

So you cannot rely on this. If the above call was made inside a async function this will refer to state of component at that point of time but we expected this to refer to property inside state at time setState calling or beginning of async task. And as task was async call thus that property may have changed in time being. Thus it is unreliable to use this keyword to refer to some property of state thus we use callback function whose arguments are previousState and props which means when async task was done and it was time to update state using setState call prevState will refer to state now when setState has not started yet. Ensuring reliability that nextState would not be corrupted.

Wrong Code: would lead to corruption of data

this.setState(
   {counter:this.state.counter+1}
 );

Correct Code with setState having call back function:

 this.setState(
       (prevState,props)=>{
           return {counter:prevState.counter+1};
        }
    );

Thus whenever we need to update our current state to next state based on value possed by property just now and all this is happening in async fashion it is good idea to use setState as callback function.

I have tried to explain it in codepen here CODE PEN

Fatal error: Call to undefined function pg_connect()

Uncommenting extension=php_pgsql.dll in the php.ini configuration files does work but, you may have to also restart your XAMPP server to finally get it working. I had to do this.

How to set a DateTime variable in SQL Server 2008?

First of all - use single quotes around your date literals!

Second of all, I would strongly recommend always using the ISO-8601 date format - this works regardless of what your locale, regional or language settings are on your SQL Server.

The ISO-8601 format is either:

  • YYYYMMDD for dates only (e.g. 20110825 for the 25th of August, 2011)
  • YYYY-MM-DDTHH:MM:SS for dates and time (e.g. 2011-08-25T14:15:00 for 25th of AUgust, 14:15/2:15pm in the afternoon)

How to decorate a class?

I'd agree inheritance is a better fit for the problem posed.

I found this question really handy though on decorating classes, thanks all.

Here's another couple of examples, based on other answers, including how inheritance affects things in Python 2.7, (and @wraps, which maintains the original function's docstring, etc.):

def dec(klass):
    old_foo = klass.foo
    @wraps(klass.foo)
    def decorated_foo(self, *args ,**kwargs):
        print('@decorator pre %s' % msg)
        old_foo(self, *args, **kwargs)
        print('@decorator post %s' % msg)
    klass.foo = decorated_foo
    return klass

@dec  # No parentheses
class Foo...

Often you want to add parameters to your decorator:

from functools import wraps

def dec(msg='default'):
    def decorator(klass):
        old_foo = klass.foo
        @wraps(klass.foo)
        def decorated_foo(self, *args ,**kwargs):
            print('@decorator pre %s' % msg)
            old_foo(self, *args, **kwargs)
            print('@decorator post %s' % msg)
        klass.foo = decorated_foo
        return klass
    return decorator

@dec('foo decorator')  # You must add parentheses now, even if they're empty
class Foo(object):
    def foo(self, *args, **kwargs):
        print('foo.foo()')

@dec('subfoo decorator')
class SubFoo(Foo):
    def foo(self, *args, **kwargs):
        print('subfoo.foo() pre')
        super(SubFoo, self).foo(*args, **kwargs)
        print('subfoo.foo() post')

@dec('subsubfoo decorator')
class SubSubFoo(SubFoo):
    def foo(self, *args, **kwargs):
        print('subsubfoo.foo() pre')
        super(SubSubFoo, self).foo(*args, **kwargs)
        print('subsubfoo.foo() post')

SubSubFoo().foo()

Outputs:

@decorator pre subsubfoo decorator
subsubfoo.foo() pre
@decorator pre subfoo decorator
subfoo.foo() pre
@decorator pre foo decorator
foo.foo()
@decorator post foo decorator
subfoo.foo() post
@decorator post subfoo decorator
subsubfoo.foo() post
@decorator post subsubfoo decorator

I've used a function decorator, as I find them more concise. Here's a class to decorate a class:

class Dec(object):

    def __init__(self, msg):
        self.msg = msg

    def __call__(self, klass):
        old_foo = klass.foo
        msg = self.msg
        def decorated_foo(self, *args, **kwargs):
            print('@decorator pre %s' % msg)
            old_foo(self, *args, **kwargs)
            print('@decorator post %s' % msg)
        klass.foo = decorated_foo
        return klass

A more robust version that checks for those parentheses, and works if the methods don't exist on the decorated class:

from inspect import isclass

def decorate_if(condition, decorator):
    return decorator if condition else lambda x: x

def dec(msg):
    # Only use if your decorator's first parameter is never a class
    assert not isclass(msg)

    def decorator(klass):
        old_foo = getattr(klass, 'foo', None)

        @decorate_if(old_foo, wraps(klass.foo))
        def decorated_foo(self, *args ,**kwargs):
            print('@decorator pre %s' % msg)
            if callable(old_foo):
                old_foo(self, *args, **kwargs)
            print('@decorator post %s' % msg)

        klass.foo = decorated_foo
        return klass

    return decorator

The assert checks that the decorator has not been used without parentheses. If it has, then the class being decorated is passed to the msg parameter of the decorator, which raises an AssertionError.

@decorate_if only applies the decorator if condition evaluates to True.

The getattr, callable test, and @decorate_if are used so that the decorator doesn't break if the foo() method doesn't exist on the class being decorated.

Get property value from C# dynamic object by string (reflection?)

Hope this would help you:

public static object GetProperty(object o, string member)
{
    if(o == null) throw new ArgumentNullException("o");
    if(member == null) throw new ArgumentNullException("member");
    Type scope = o.GetType();
    IDynamicMetaObjectProvider provider = o as IDynamicMetaObjectProvider;
    if(provider != null)
    {
        ParameterExpression param = Expression.Parameter(typeof(object));
        DynamicMetaObject mobj = provider.GetMetaObject(param);
        GetMemberBinder binder = (GetMemberBinder)Microsoft.CSharp.RuntimeBinder.Binder.GetMember(0, member, scope, new CSharpArgumentInfo[]{CSharpArgumentInfo.Create(0, null)});
        DynamicMetaObject ret = mobj.BindGetMember(binder);
        BlockExpression final = Expression.Block(
            Expression.Label(CallSiteBinder.UpdateLabel),
            ret.Expression
        );
        LambdaExpression lambda = Expression.Lambda(final, param);
        Delegate del = lambda.Compile();
        return del.DynamicInvoke(o);
    }else{
        return o.GetType().GetProperty(member, BindingFlags.Public | BindingFlags.Instance).GetValue(o, null);
    }
}

Html table tr inside td

Full Example:

_x000D_
_x000D_
<table border="1" style="width:100%;">
  <tr>
    <td>ABC</td>
    <td>ABC</td>
    <td>ABC</td>
    <td>ABC</td>
  </tr>
  <tr>
    <td>Item 1</td>
    <td>Item 1</td>
    <td>
      <table border="1" style="width: 100%;">
        <tr>
          <td>Name 1</td>
          <td>Price 1</td>
        </tr>
        <tr>
          <td>Name 2</td>
          <td>Price 2</td>
        </tr>
        <tr>
          <td>Name 3</td>
          <td>Price 3</td>
        </tr>
      </table>
    </td>
    <td>Item 1</td>
  </tr>
  <tr>
    <td>Item 2</td>
    <td>Item 2</td>
    <td>Item 2</td>
    <td>Item 2</td>
  </tr>
  <tr>
    <td>Item 3</td>
    <td>Item 3</td>
    <td>Item 3</td>
    <td>Item 3</td>
  </tr>
</table>
_x000D_
_x000D_
_x000D_

Failed to find 'ANDROID_HOME' environment variable

I would like to share an answer that also demonstrates approach using the Android SDK provided by the Ubuntu repository:

Install Android SDK

sudo apt-get install android-sdk

Export environmental variables

export ANDROID_HOME="/usr/lib/android-sdk/"
export PATH="${PATH}:${ANDROID_HOME}tools/:${ANDROID_HOME}platform-tools/"

Where are static methods and static variables stored in Java?

It is stored in the heap referenced by the class definition. If you think about it, it has nothing to do with stack because there is no scope.

Checking for empty or null JToken in a JObject

To check whether a property exists on a JObject, you can use the square bracket syntax and see whether the result is null or not. If the property exists, a JToken will be always be returned (even if it has the value null in the JSON).

JToken token = jObject["param"];
if (token != null)
{
    // the "param" property exists
}

If you have a JToken in hand and you want to see if it is non-empty, well, that depends on what type of JToken it is and how you define "empty". I usually use an extension method like this:

public static class JsonExtensions
{
    public static bool IsNullOrEmpty(this JToken token)
    {
        return (token == null) ||
               (token.Type == JTokenType.Array && !token.HasValues) ||
               (token.Type == JTokenType.Object && !token.HasValues) ||
               (token.Type == JTokenType.String && token.ToString() == String.Empty) ||
               (token.Type == JTokenType.Null);
    }
}

Bulk Insert Correctly Quoted CSV File in SQL Server

Been stung by the same :)

I wrapped this logic into a function to clean up data that had been was already imported

DECLARE @str NVARCHAR(MAX);
DECLARE @quote_identifier NVARCHAR(MAX);

SET @quote_identifier = N'"';

SET @str = N'"quoted stuff"';

SELECT IIF(
           LEFT(@str, 1) = @quote_identifier
           AND RIGHT(@str, 1) = @quote_identifier,
           SUBSTRING(@str, DATALENGTH(@quote_identifier), LEN(@str) - DATALENGTH(@quote_identifier)),
           @str);

Relation between CommonJS, AMD and RequireJS?

The short answer would be:

CommonJS and AMD are specifications (or formats) on how modules and their dependencies should be declared in javascript applications.

RequireJS is a script loader library that is AMD compliant, curljs being another example.

CommonJS compliant:

Taken from Addy Osmani's book.

// package/lib is a dependency we require
var lib = require( "package/lib" );

// behavior for our module
function foo(){
    lib.log( "hello world!" );
}

// export (expose) foo to other modules as foobar
exports.foobar = foo;

AMD compliant:

// package/lib is a dependency we require
define(["package/lib"], function (lib) {

    // behavior for our module
    function foo() {
        lib.log( "hello world!" );
    }

    // export (expose) foo to other modules as foobar
    return {
        foobar: foo
    }
});

Somewhere else the module can be used with:

require(["package/myModule"], function(myModule) {
    myModule.foobar();
});

Some background:

Actually, CommonJS is much more than an API declaration and only a part of it deals with that. AMD started as a draft specification for the module format on the CommonJS list, but full consensus wasn't reached and further development of the format moved to the amdjs group. Arguments around which format is better state that CommonJS attempts to cover a broader set of concerns and that it's better suited for server side development given its synchronous nature, and that AMD is better suited for client side (browser) development given its asynchronous nature and the fact that it has its roots in Dojo's module declaration implementation.

Sources:

How to avoid a System.Runtime.InteropServices.COMException?

I came across System.Runtime.InteropServices.COMException while opening a project solution. Sometimes user doesn't have enough priveleges to run some COM Methods. I ran Visual Studio as Administrator and the exception was gone.

ubuntu "No space left on device" but there is tons of space

It's possible that you've run out of memory or some space elsewhere and it prompted the system to mount an overflow filesystem, and for whatever reason, it's not going away.

Try unmounting the overflow partition:

umount /tmp

or

umount overflow