Programs & Examples On #Contention

Questions about any type of resource contention. Use in conjunction with the applicable tag such as [file-access], [memory] or [locking] to indicate the type of resource being referred to.

How can I change the width and height of slides on Slick Carousel?

Basically you need to edit the JS and add (in this case, inside $('#featured-articles').slick({ ), this:

variableWidth: true,

This will allow you to edit the width in your CSS where you can, generically use:

.slick-slide {
    width: 100%;
}

or in this case:

.featured {
    width: 100%;
}

How to choose the id generation strategy when using JPA and Hibernate

The API Doc are very clear on this.

All generators implement the interface org.hibernate.id.IdentifierGenerator. This is a very simple interface. Some applications can choose to provide their own specialized implementations, however, Hibernate provides a range of built-in implementations. The shortcut names for the built-in generators are as follows:

increment

generates identifiers of type long, short or int that are unique only when no other process is inserting data into the same table. Do not use in a cluster.

identity

supports identity columns in DB2, MySQL, MS SQL Server, Sybase and HypersonicSQL. The returned identifier is of type long, short or int.

sequence

uses a sequence in DB2, PostgreSQL, Oracle, SAP DB, McKoi or a generator in Interbase. The returned identifier is of type long, short or int

hilo

uses a hi/lo algorithm to efficiently generate identifiers of type long, short or int, given a table and column (by default hibernate_unique_key and next_hi respectively) as a source of hi values. The hi/lo algorithm generates identifiers that are unique only for a particular database.

seqhilo

uses a hi/lo algorithm to efficiently generate identifiers of type long, short or int, given a named database sequence.

uuid

uses a 128-bit UUID algorithm to generate identifiers of type string that are unique within a network (the IP address is used). The UUID is encoded as a string of 32 hexadecimal digits in length.

guid

uses a database-generated GUID string on MS SQL Server and MySQL.

native

selects identity, sequence or hilo depending upon the capabilities of the underlying database.

assigned

lets the application assign an identifier to the object before save() is called. This is the default strategy if no element is specified.

select

retrieves a primary key, assigned by a database trigger, by selecting the row by some unique key and retrieving the primary key value.

foreign

uses the identifier of another associated object. It is usually used in conjunction with a primary key association.

sequence-identity

a specialized sequence generation strategy that utilizes a database sequence for the actual value generation, but combines this with JDBC3 getGeneratedKeys to return the generated identifier value as part of the insert statement execution. This strategy is only supported on Oracle 10g drivers targeted for JDK 1.4. Comments on these insert statements are disabled due to a bug in the Oracle drivers.

If you are building a simple application with not much concurrent users, you can go for increment, identity, hilo etc.. These are simple to configure and did not need much coding inside the db.

You should choose sequence or guid depending on your database. These are safe and better because the id generation will happen inside the database.

Update: Recently we had an an issue with idendity where primitive type (int) this was fixed by using warapper type (Integer) instead.

Why catch and rethrow an exception in C#?

It depends what you are doing in the catch block, and if you are wanting to pass the error on to the calling code or not.

You might say Catch io.FileNotFoundExeption ex and then use an alternative file path or some such, but still throw the error on.

Also doing Throw instead of Throw Ex allows you to keep the full stack trace. Throw ex restarts the stack trace from the throw statement (I hope that makes sense).

How do you implement a circular buffer in C?

Here is a simple solution in C. Assume interrupts are turned off for each function. No polymorphism & stuff, just common sense.


#define BUFSIZE 128
char buf[BUFSIZE];
char *pIn, *pOut, *pEnd;
char full;

// init
void buf_init()
{
    pIn = pOut = buf;       // init to any slot in buffer
    pEnd = &buf[BUFSIZE];   // past last valid slot in buffer
    full = 0;               // buffer is empty
}

// add char 'c' to buffer
int buf_put(char c)
{
    if (pIn == pOut  &&  full)
        return 0;           // buffer overrun

    *pIn++ = c;             // insert c into buffer
    if (pIn >= pEnd)        // end of circular buffer?
        pIn = buf;          // wrap around

    if (pIn == pOut)        // did we run into the output ptr?
        full = 1;           // can't add any more data into buffer
    return 1;               // all OK
}

// get a char from circular buffer
int buf_get(char *pc)
{
    if (pIn == pOut  &&  !full)
        return 0;           // buffer empty  FAIL

    *pc = *pOut++;              // pick up next char to be returned
    if (pOut >= pEnd)       // end of circular buffer?
        pOut = buf;         // wrap around

    full = 0;               // there is at least 1 slot
    return 1;               // *pc has the data to be returned
}

When is assembly faster than C?

A few examples from my experience:

  • Access to instructions that are not accessible from C. For instance, many architectures (like x86-64, IA-64, DEC Alpha, and 64-bit MIPS or PowerPC) support a 64 bit by 64 bit multiplication producing a 128 bit result. GCC recently added an extension providing access to such instructions, but before that assembly was required. And access to this instruction can make a huge difference on 64-bit CPUs when implementing something like RSA - sometimes as much as a factor of 4 improvement in performance.

  • Access to CPU-specific flags. The one that has bitten me a lot is the carry flag; when doing a multiple-precision addition, if you don't have access to the CPU carry bit one must instead compare the result to see if it overflowed, which takes 3-5 more instructions per limb; and worse, which are quite serial in terms of data accesses, which kills performance on modern superscalar processors. When processing thousands of such integers in a row, being able to use addc is a huge win (there are superscalar issues with contention on the carry bit as well, but modern CPUs deal pretty well with it).

  • SIMD. Even autovectorizing compilers can only do relatively simple cases, so if you want good SIMD performance it's unfortunately often necessary to write the code directly. Of course you can use intrinsics instead of assembly but once you're at the intrinsics level you're basically writing assembly anyway, just using the compiler as a register allocator and (nominally) instruction scheduler. (I tend to use intrinsics for SIMD simply because the compiler can generate the function prologues and whatnot for me so I can use the same code on Linux, OS X, and Windows without having to deal with ABI issues like function calling conventions, but other than that the SSE intrinsics really aren't very nice - the Altivec ones seem better though I don't have much experience with them). As examples of things a (current day) vectorizing compiler can't figure out, read about bitslicing AES or SIMD error correction - one could imagine a compiler that could analyze algorithms and generate such code, but it feels to me like such a smart compiler is at least 30 years away from existing (at best).

On the other hand, multicore machines and distributed systems have shifted many of the biggest performance wins in the other direction - get an extra 20% speedup writing your inner loops in assembly, or 300% by running them across multiple cores, or 10000% by running them across a cluster of machines. And of course high level optimizations (things like futures, memoization, etc) are often much easier to do in a higher level language like ML or Scala than C or asm, and often can provide a much bigger performance win. So, as always, there are tradeoffs to be made.

Split string into tokens and save them in an array

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

int main ()
{
    char buf[] ="abc/qwe/ccd";
    int i = 0;
    char *p = strtok (buf, "/");
    char *array[3];

    while (p != NULL)
    {
        array[i++] = p;
        p = strtok (NULL, "/");
    }

    for (i = 0; i < 3; ++i) 
        printf("%s\n", array[i]);

    return 0;
}

Updating records codeigniter

In codeigniter doc if you update specific field just do this

$data = array(
    'yourfieldname' => value,
    'name' => $name,
    'date' => $date
);

$this->db->where('yourfieldname', yourfieldvalue);
$this->db->update('yourtablename', $data);

How to align content of a div to the bottom

Seems to be working:

HTML: I'm at the bottom

css:

h1.alignBtm {
  line-height: 3em;
}
h1.alignBtm span {
  line-height: 1.2em;
  vertical-align: bottom;
}

"SDK Platform Tools component is missing!"

The latest version of the Android SDK ships with two different applications: an SDK Manager and an AVD Manager rather than one single app that was valid when this question was originally asked.

My particular problem was unrelated to the other suggestions. I'm on a network at the moment where HTTPS traffic is mostly disallowed. In order to install the Android Platform Tools I needed to turn on the option to "Force https://... sources to be fetched using http://..." and then this allowed me to install the other tools.

CSS values using HTML5 data attribute

There is, indeed, prevision for such feature, look http://www.w3.org/TR/css3-values/#attr-notation

This fiddle should work like what you need, but will not for now.

Unfortunately, it's still a draft, and isn't fully implemented on major browsers.

It does work for content on pseudo-elements, though.

how to compare two string dates in javascript?

var d1 = Date.parse("2012-11-01");
var d2 = Date.parse("2012-11-04");
if (d1 < d2) {
    alert ("Error!");
}

Demo Jsfiddle

How to do a join in linq to sql with method syntax?

To add on to the other answers here, if you would like to create a new object of a third different type with a where clause (e.g. one that is not your Entity Framework object) you can do this:

public IEnumerable<ThirdNonEntityClass> demoMethod(IEnumerable<int> property1Values)
{
    using(var entityFrameworkObjectContext = new EntityFrameworkObjectContext )
    {
        var result = entityFrameworkObjectContext.SomeClass
            .Join(entityFrameworkObjectContext.SomeOtherClass,
                sc => sc.property1,
                soc => soc.property2,
                (sc, soc) => new {sc, soc})
            .Where(s => propertyValues.Any(pvals => pvals == es.sc.property1)
            .Select(s => new ThirdNonEntityClass 
            {
                dataValue1 = s.sc.dataValueA,
                dataValue2 = s.soc.dataValueB
            })
            .ToList();
    }

    return result;

}    

Pay special attention to the intermediate object that is created in the Where and Select clauses.

Note that here we also look for any joined objects that have a property1 that matches one of the ones in the input list.

I know this is a bit more complex than what the original asker was looking for, but hopefully it will help someone.

Best way to check function arguments?

The most Pythonic idiom is to clearly document what the function expects and then just try to use whatever gets passed to your function and either let exceptions propagate or just catch attribute errors and raise a TypeError instead. Type-checking should be avoided as much as possible as it goes against duck-typing. Value testing can be OK – depending on the context.

The only place where validation really makes sense is at system or subsystem entry point, such as web forms, command line arguments, etc. Everywhere else, as long as your functions are properly documented, it's the caller's responsibility to pass appropriate arguments.

jQuery-- Populate select from json

Only change the DOM once...

var listitems = '';
$.each(temp, function(key, value){
    listitems += '<option value=' + key + '>' + value + '</option>';
});
$select.append(listitems);

Getting "Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?" when installing lxml through pip

On Mac OS X El Capitan I had to run these two commands to fix this error:

xcode-select --install
pip install lxml

Which ended up installing lxml-3.5.0

When you run the xcode-select command you may have to sign a EULA (so have an X-Term handy for the UI if you're doing this on a headless machine).

How to generate all permutations of a list?

And in Python 2.6 onwards:

import itertools
itertools.permutations([1,2,3])

(returned as a generator. Use list(permutations(l)) to return as a list.)

How to generate UL Li list from string array using jquery?

With ES6 you can write this:

const countries = ['United States', 'Canada', 'Argentina', 'Armenia'];

const $ul = $('<ul>', { class: "mylist" }).append(
  countries.map(country => 
    $("<li>").append($("<a>").text(country))
  )
);

Background image jumps when address bar hides iOS/Android/Mobile Chrome

I set my width element, with javascript. After I set the de vh.

html

<div id="gifimage"><img src="back_phone_back.png" style="width: 100%"></div>

css

#gifimage {
    position: absolute;
    height: 70vh;
}

javascript

imageHeight = document.getElementById('gifimage').clientHeight;

// if (isMobile)       
document.getElementById('gifimage').setAttribute("style","height:" + imageHeight + "px");

This works for me. I don't use jquery ect. because I want it to load as soon as posible.

How do I convert an object to an array?

I had the same problem and I solved it with get_object_vars mentioned above.

Furthermore, I had to convert my object with json_decode and I had to iterate the array with the oldschool "for" loop (rather then for-each).

How to use JavaScript with Selenium WebDriver Java

You can also try clicking by JavaScript:

WebElement button = driver.findElement(By.id("someid"));
JavascriptExecutor jse = (JavascriptExecutor)driver;
jse.executeScript("arguments[0].click();", button);

Also you can use jquery. In worst cases, for stubborn pages it may be necessary to do clicks by custom EXE application. But try the obvious solutions first.

Find PHP version on windows command line

xampp control panel->shell->type php-v you get the version of php of your xampp installed

DB(mariadb/mysql)version type localhost/phpmyadmin in url click enter click on sql type select version(); enter to get the mysql or mariaDb version

How to stop creating .DS_Store on Mac?

this file starts to appear when you choose the system shows you the hidden files: $defaults write com.apple.finder AppleShowAllFiles TRUE If you run this command disapear $defaults write com.apple.finder AppleShowAllFiles FALSE Use terminal

How to tell if a file is git tracked (by shell exit code)?

try:

git ls-files --error-unmatch <file name>

will exit with 1 if file is not tracked

Check if a string has a certain piece of text

Here you go: ES5

var test = 'Hello World';
if( test.indexOf('World') >= 0){
  // Found world
}

With ES6 best way would be to use includes function to test if the string contains the looking work.

const test = 'Hello World';
if (test.includes('World')) { 
  // Found world
}

How to replace blank (null ) values with 0 for all records?

UPDATE YourTable SET MyField = 0 WHERE MyField IS NULL

works in most SQL dialects. I don't use Access, but that should get you started.

Google Chrome redirecting localhost to https

This can be caused by a cached https redirect, and can be fixed by clearing the cache manually as in Adiyat Mubarak's answer.

But if you are visiting localhost you likely are a developer, in which case you will find a cache clearing chrome extension such as "classic cache killer" (see e.g. https://chrome.google.com/webstore/search/classic%20cache%20killer?hl=en) useful in a variety of situations, and likely already have one installed.

So the quick fix is: Install a cache killer (if you don't have one already), turn it on, and reload the page. Done!

How do I check if an integer is even or odd?

You guys are waaaaaaaay too efficient. What you really want is:

public boolean isOdd(int num) {
  int i = 0;
  boolean odd = false;

  while (i != num) {
    odd = !odd;
    i = i + 1;
  }

  return odd;
}

Repeat for isEven.

Of course, that doesn't work for negative numbers. But with brilliance comes sacrifice...

javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"Group")

I had the same problem.. It helped me, I'm specify the same field names of my classes as the tag names in the xml file (the file comes from an external system).

For example:

My xml file:

<Response>
  <ESList>
     <Item>
        <ID>1</ID>
        <Name>Some name 1</Name>
        <Code>Some code</Code>
        <Url>Some Url</Url>
        <RegionList>
           <Item>
              <ID>2</ID>
              <Name>Some name 2</Name>
           </Item>
        </RegionList>
     </Item>
  </ESList>
</Response>

My Response class:

@XmlRootElement(name="Response")
@XmlAccessorType(XmlAccessType.FIELD)
public class Response {
    @XmlElement
    private ESList[] ESList = new ESList[1]; // as the tag name in the xml file..

    // getter and setter here
}

My ESList class:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name="ESList")
public class ESList {
    @XmlElement
    private Item[] Item = new Item[1]; // as the tag name in the xml file..

    // getters and setters here
}

My Item class:

@XmlRootElement(name="Item")
@XmlAccessorType(XmlAccessType.FIELD)
public class Item {
    @XmlElement
    private String ID; // as the tag name in the xml file..
    @XmlElement
    private String Name; // and so on...
    @XmlElement
    private String Code;
    @XmlElement
    private String Url;
    @XmlElement
    private RegionList[] RegionList = new RegionList[1];

    // getters and setters here
}

My RegionList class:

@XmlRootElement(name="RegionList")
@XmlAccessorType(XmlAccessType.FIELD)
public class RegionList {
    Item[] Item = new Item[1];

    // getters and setters here
}

My DemoUnmarshalling class:

public class DemoUnmarshalling {
    public static void main(String[] args) {
        try {
            File file = new File("...");

            JAXBContext jaxbContext = JAXBContext.newInstance(Response.class);
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            jaxbUnmarshaller.setEventHandler(
                new ValidationEventHandler() {
                    public boolean handleEvent(ValidationEvent event ) {
                        throw new RuntimeException(event.getMessage(),
                            event.getLinkedException());
                    }
                }
            );

            Response response = (Response) jaxbUnmarshaller.unmarshal(file);

            ESList[] esList = response.getESList();
            Item[] item = esList[0].getItem();
            RegionList[] regionLists = item[0].getRegionList();
            Item[] regionListItem = regionLists[0].getItem();

            System.out.println(item[0].getID());
            System.out.println(item[0].getName());
            System.out.println(item[0].getCode());
            System.out.println(item[0].getUrl());
            System.out.println(regionListItem[0].getID());
            System.out.println(regionListItem[0].getName());

        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

It gives:

1
Some name 1
Some code
Some Url
2
Some name 2

File size exceeds configured limit (2560000), code insight features not available

Edit config file for IDEA: IDEA_HOME/bin/idea.properties

# Maximum file size (kilobytes) IDE should provide code assistance for.
idea.max.intellisense.filesize=60000

# Maximum file size (kilobytes) IDE is able to open.
idea.max.content.load.filesize=60000

Save and restart IDEA

What is the difference between sscanf or atoi to convert a string to an integer?

To @R.. I think it's not enough to check errno for error detection in strtol call.

long strtol (const char *String, char **EndPointer, int Base)

You'll also need to check EndPointer for errors.

How do you set, clear, and toggle a single bit?

As this is tagged "embedded" I'll assume you're using a microcontroller. All of the above suggestions are valid & work (read-modify-write, unions, structs, etc.).

However, during a bout of oscilloscope-based debugging I was amazed to find that these methods have a considerable overhead in CPU cycles compared to writing a value directly to the micro's PORTnSET / PORTnCLEAR registers which makes a real difference where there are tight loops / high-frequency ISR's toggling pins.

For those unfamiliar: In my example, the micro has a general pin-state register PORTn which reflects the output pins, so doing PORTn |= BIT_TO_SET results in a read-modify-write to that register. However, the PORTnSET / PORTnCLEAR registers take a '1' to mean "please make this bit 1" (SET) or "please make this bit zero" (CLEAR) and a '0' to mean "leave the pin alone". so, you end up with two port addresses depending whether you're setting or clearing the bit (not always convenient) but a much faster reaction and smaller assembled code.

CodeIgniter: Load controller within controller

Just use

..............

self::index();

..............

How to describe table in SQL Server 2008?

The sp_help built-in procedure is the SQL Server's closest thing to Oracle's DESC function IMHO

sp_help MyTable

Use

sp_help "[SchemaName].[TableName]" 

or

sp_help "[InstanceName].[SchemaName].[TableName]"

in case you need to qualify the table name further

Remove blank values from array using C#

If you are using .NET 3.5+ you could use LINQ (Language INtegrated Query).

test = test.Where(x => !string.IsNullOrEmpty(x)).ToArray();

Add new field to every document in a MongoDB collection

if you are using mongoose try this,after mongoose connection

async ()=> await Mongoose.model("collectionName").updateMany({}, {$set: {newField: value}})

JAXB :Need Namespace Prefix to all the elements

To specify more than one namespace to provide prefixes, use something like:

@javax.xml.bind.annotation.XmlSchema(
    namespace = "urn:oecd:ties:cbc:v1", 
    elementFormDefault = javax.xml.bind.annotation.XmlNsForm.QUALIFIED,
    xmlns ={@XmlNs(prefix="cbc", namespaceURI="urn:oecd:ties:cbc:v1"), 
            @XmlNs(prefix="iso", namespaceURI="urn:oecd:ties:isocbctypes:v1"),
            @XmlNs(prefix="stf", namespaceURI="urn:oecd:ties:stf:v4")})

... in package-info.java

Does the Java &= operator apply & or &&?

see 15.22.2 of the JLS. For boolean operands, the & operator is boolean, not bitwise. The only difference between && and & for boolean operands is that for && it is short circuited (meaning that the second operand isn't evaluated if the first operand evaluates to false).

So in your case, if b is a primitive, a = a && b, a = a & b, and a &= b all do the same thing.

MySQL Great Circle Distance (Haversine formula)

 SELECT *, (  
    6371 * acos(cos(radians(search_lat)) * cos(radians(lat) ) *   
cos(radians(lng) - radians(search_lng)) + sin(radians(search_lat)) *         sin(radians(lat)))  
) AS distance  
FROM table  
WHERE lat != search_lat AND lng != search_lng AND distance < 25  
 ORDER BY distance  
FETCH 10 ONLY 

for distance of 25 km

How to download excel (.xls) file from API in postman?

You can Just save the response(pdf,doc etc..) by option on the right side of the response in postman check this image postman save response

For more Details check this

https://learning.getpostman.com/docs/postman/sending_api_requests/responses/

How to convert PDF files to images

There is a free nuget package (Pdf2Image), which allows the extraction of pdf pages to jpg files or to a collection of images (List ) in just one line

        string file = "c:\\tmp\\test.pdf";

        List<System.Drawing.Image> images = PdfSplitter.GetImages(file, PdfSplitter.Scale.High);

        PdfSplitter.WriteImages(file, "c:\\tmp", PdfSplitter.Scale.High, PdfSplitter.CompressionLevel.Medium);

All source is also available on github Pdf2Image

Compare two files in Visual Studio

You can invoke devenv.exe /diff list1.txt list2.txt from the VS Developer Command Prompt or, if a Visual Studio instance is already running, you can type Tools.DiffFiles in the Command window, with a handy file name completion:

Using Tools.DiffFiles from Visual Studio Command window

FTP/SFTP access to an Amazon S3 Bucket

WinSCp now supports S3 protocol

First, make sure your AWS user with S3 access permissions has an “Access key ID” created. You also have to know the “Secret access key”. Access keys are created and managed on Users page of IAM Management Console.

Make sure New site node is selected.

On the New site node, select Amazon S3 protocol.

Enter your AWS user Access key ID and Secret access key

Save your site settings using the Save button.

Login using the Login button.

What primitive data type is time_t?

You can use the function difftime. It returns the difference between two given time_t values, the output value is double (see difftime documentation).

time_t actual_time;
double actual_time_sec;
actual_time = time(0);
actual_time_sec = difftime(actual_time,0); 
printf("%g",actual_time_sec);

Best way to Bulk Insert from a C# DataTable

string connectionString= ServerName + DatabaseName + SecurityType;
using (SqlConnection connection = new SqlConnection(connectionString))
using (SqlBulkCopy bulkCopy = new SqlBulkCopy(connection)) {
    connection.Open();
    bulkCopy.DestinationTableName = "TableName";
    try {
        bulkCopy.WriteToServer(dataTableName);
    } catch (Exception e) {
        Console.Write(e.Message);
    }
}

Please note that the structure of the database table and the table name should be the same or it will throw an exception.

Get Environment Variable from Docker Container

None of the above answers show you how to extract a variable from a non-running container (if you use the echo approach with run, you won't get any output).

Simply run with printenv, like so:

docker run --rm <container> printenv <MY_VAR>

(Note that docker-compose instead of docker works too)

curl usage to get header

curl --head https://www.example.net

I was pointed to this by curl itself; when I issued the command with -X HEAD, it printed:

Warning: Setting custom HTTP method to HEAD with -X/--request may not work the 
Warning: way you want. Consider using -I/--head instead.

Change bootstrap navbar collapse breakpoint without using LESS

The Sass way of changing bootstrap variables is actually documented on the bootstrap-sass github page.

Just redefine the variables before you @import bootstrap:

$grid-float-breakpoint: 1000px;

@import 'bootstrap';

How do I analyze a program's core dump file with GDB when it has command-line parameters?

You can analyze the core dump file using the "gdb" command.

 gdb - The GNU Debugger

 syntax:

 # gdb executable-file core-file

 example: # gdb out.txt core.xxx 

TypeError: 'undefined' is not an object

try out this if you want to assign value to object and it is showing this error in angular..

crate object in construtor

this.modelObj = new Model(); //<---------- after declaring object above

Breaking a list into multiple columns in Latex

Another option to avoid nesting two different environments (like multicols and enumerate).

The environment called tasks from the package with the same name seems to me very easy to customize thanks to a variety of options (pdf guide here).

This code:

\documentclass{article}
\usepackage{tasks}

%\settasks{style=itemize}

\begin{document}
Text text text text text text text text text text text text 
text text text text text text text text text text text text 
text text text text text text text text text text text text.

\begin{tasks}(2)
\task[*] a
\task[*] b
\task[*] c
\task[*] d
\task[*] e
\task[*] f
\end{tasks}    

Text text text text text text text text text text text text 
text text text text text text text text text text text text 
text text text text text text text text text text text text.
\end{document}

produces this output

tasks

The package tasks was updated in August 2020 and it was originally created specifically for horizontally columned lists (see the screenshot just above here), the motivations behind this are resumed in the guide. If such arrangement of the items/tasks is acceptable, then this may be a good choice since it keeps - IMHO - the code tidy and flexible.

"VT-x is not available" when I start my Virtual machine

You might try reducing your base memory under settings to around 3175MB and reduce your cores to 1. That should work given that your BIOS is set for virtualization. Use the f12 key, security, virtualization to make sure that it is enabled. If it doesn't say VT-x that is ok, it should say VT-d or the like.

Is it better to use C void arguments "void foo(void)" or not "void foo()"?

In C++, there is no difference in main() and main(void).

But in C, main() will be called with any number of parameters.

Example:

main ( ){
    main(10,"abc",12.28);
    //Works fine !
    //It won't give the error. The code will compile successfully.
    //(May cause Segmentation fault when run)
}

main(void) will be called without any parameters. If we try to pass then this end up leading to a compiler error.

Example:

main (void) {
     main(10,"abc",12.13);
     //This throws "error: too many arguments to function ‘main’ "
}

Error - SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM

This error occurs if you are trying to set variable of type DateTime to null. Declare the variable as nullable, i.e. DateTime? . This will solve the problem.

Linq to Entities - SQL "IN" clause

I will go for Inner Join in this context. If I would have used contains, it would iterate 6 times despite if the fact that there are just one match.

var desiredNames = new[] { "Pankaj", "Garg" }; 

var people = new[]  
{  
    new { FirstName="Pankaj", Surname="Garg" },  
    new { FirstName="Marc", Surname="Gravell" },  
    new { FirstName="Jeff", Surname="Atwood" }  
}; 

var records = (from p in people join filtered in desiredNames on p.FirstName equals filtered  select p.FirstName).ToList(); 

Disadvantages of Contains

Suppose I have two list objects.

List 1      List 2
  1           12
  2            7
  3            8
  4           98
  5            9
  6           10
  7            6

Using Contains, it will search for each List 1 item in List 2 that means iteration will happen 49 times !!!

Running interactive commands in Paramiko

Take a look at example and do in similar way

(sorce from http://jessenoller.com/2009/02/05/ssh-programming-with-paramiko-completely-different/):

    ssh.connect('127.0.0.1', username='jesse', 
        password='lol')
    stdin, stdout, stderr = ssh.exec_command(
        "sudo dmesg")
    stdin.write('lol\n')
    stdin.flush()
    data = stdout.read.splitlines()
    for line in data:
        if line.split(':')[0] == 'AirPort':
            print line

Where are SQL Server connection attempts logged?

If you'd like to track only failed logins, you can use the SQL Server Audit feature (available in SQL Server 2008 and above). You will need to add the SQL server instance you want to audit, and check the failed login operation to audit.

Note: tracking failed logins via SQL Server Audit has its disadvantages. For example - it doesn't provide the names of client applications used.

If you want to audit a client application name along with each failed login, you can use an Extended Events session.

To get you started, I recommend reading this article: http://www.sqlshack.com/using-extended-events-review-sql-server-failed-logins/

Video format or MIME type is not supported

For Ubuntu 14.04

Just removed the package Oxideqt-dodecs then install flash or ubuntu restricted extras

and you are good to go!!

How to return result of a SELECT inside a function in PostgreSQL?

Hi please check the below link

https://www.postgresql.org/docs/current/xfunc-sql.html

EX:

CREATE FUNCTION sum_n_product_with_tab (x int)
RETURNS TABLE(sum int, product int) AS $$
    SELECT $1 + tab.y, $1 * tab.y FROM tab;
$$ LANGUAGE SQL;

How to combine two strings together in PHP?

$result = $data1 . $data2;

This is called string concatenation. Your example lacks a space though, so for that specifically, you would need:

$result = $data1 . ' ' . $data2;

executing shell command in background from script

Leave off the quotes

$cmd &
$othercmd &

eg:

nicholas@nick-win7 /tmp
$ cat test
#!/bin/bash

cmd="ls -la"

$cmd &


nicholas@nick-win7 /tmp
$ ./test

nicholas@nick-win7 /tmp
$ total 6
drwxrwxrwt+ 1 nicholas root    0 2010-09-10 20:44 .
drwxr-xr-x+ 1 nicholas root 4096 2010-09-10 14:40 ..
-rwxrwxrwx  1 nicholas None   35 2010-09-10 20:44 test
-rwxr-xr-x  1 nicholas None   41 2010-09-10 20:43 test~

Creating a Jenkins environment variable using Groovy

As other answers state setting new ParametersAction is the way to inject one or more environment variables, but when a job is already parameterised adding new action won't take effect. Instead you'll see two links to a build parameters pointing to the same set of parameters and the one you wanted to add will be null.

Here is a snippet updating the parameters list in both cases (a parametrised and non-parametrised job):

import hudson.model.*

def build = Thread.currentThread().executable

def env = System.getenv()
def version = env['currentversion']
def m = version =~/\d{1,2}/
def minVerVal = m[0]+"."+m[1]

def newParams = null

def pl = new ArrayList<StringParameterValue>()
pl.add(new StringParameterValue('miniVersion', miniVerVal))

def oldParams = build.getAction(ParametersAction.class)

if(oldParams != null) {
  newParams = oldParams.createUpdated(pl)
  build.actions.remove(oldParams)
} else {
  newParams = new ParametersAction(pl)
}

build.addAction(newParams)

Node.js console.log() not logging anything

This can be confusing for anyone using nodejs for the first time. It is actually possible to pipe your node console output to the browser console. Take a look at connect-browser-logger on github

UPDATE: As pointed out by Yan, connect-browser-logger appears to be defunct. I would recommend NodeMonkey as detailed here : Output to Chrome console from Node.js

How to read appSettings section in the web.config file?

Here's the easy way to get access to the web.config settings anywhere in your C# project.

 Properties.Settings.Default

Use case:

litBodyText.Text = Properties.Settings.Default.BodyText;
litFootText.Text = Properties.Settings.Default.FooterText;
litHeadText.Text = Properties.Settings.Default.HeaderText;

Web.config file:

  <applicationSettings>
    <myWebSite.Properties.Settings> 
      <setting name="BodyText" serializeAs="String">
        <value>
          &lt;h1&gt;Hello World&lt;/h1&gt;
          &lt;p&gt;
      Ipsum Lorem
          &lt;/p&gt;
        </value>
      </setting>
      <setting name="HeaderText" serializeAs="String">
      My header text
        <value />
      </setting>
      <setting name="FooterText" serializeAs="String">
      My footer text
        <value />
      </setting>
    </myWebSite.Properties.Settings>
  </applicationSettings>

No need for special routines - everything is right there already. I'm surprised that no one has this answer for the best way to read settings from your web.config file.

How to remove the querystring and get only the url?

To remove the query string from the request URI, replace the query string with an empty string:

function request_uri_without_query() {
    $result = $_SERVER['REQUEST_URI'];
    $query = $_SERVER['QUERY_STRING'];
    if(!empty($query)) {
        $result = str_replace('?' . $query, '', $result);
    }
    return $result;
}

List columns with indexes in PostgreSQL

@cope360 's excellent answer, converted to use join syntax.

select t.relname as table_name
     , i.relname as index_name
     , array_to_string(array_agg(a.attname), ', ') as column_names
from pg_class t
join pg_index ix
on t.oid = ix.indrelid
join pg_class i
on i.oid = ix.indexrelid
join pg_attribute a
on a.attrelid = t.oid
and a.attnum = ANY(ix.indkey)
where t.relkind = 'r'
and t.relname like 'test%'
group by t.relname
       , i.relname
order by t.relname
       , i.relname
;

conversion of a varchar data type to a datetime data type resulted in an out-of-range value

I know that this solution is a little different from the OP's case, but as you may have been redirected here from searching on google the title of this question, as I did, maybe you're facing the same problem I had.
Sometimes you get this error because your date time is not valid, i.e. your date (in string format) points to a day which exceeds the number of days of that month! e.g.: CONVERT(Datetime, '2015-06-31') caused me this error, while I was converting a statement from MySql (which didn't argue! and makes the error really harder to catch) to SQL Server.

PHP, display image with Header()

Browsers make their best guess with the data they receive. This works for markup (which Websites often get wrong) and other media content. A program that receives a file can often figure out what its received regardless of the MIME content type it's been told.

This isn't something you should rely on however. It's recommended you always use the correct MIME content.

How do I list all cron jobs for all users?

for user in $(cut -f1 -d: /etc/passwd); 
do 
    echo $user; crontab -u $user -l; 
done

What is the difference between ApplicationContext and WebApplicationContext in Spring MVC?

Going back to Servlet days, web.xml can have only one <context-param>, so only one context object gets created when server loads an application and the data in that context is shared among all resources (Ex: Servlets and JSPs). It is same as having Database driver name in the context, which will not change. In similar way, when we declare contextConfigLocation param in <contex-param> Spring creates one Application Context object.

 <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>com.myApp.ApplicationContext</param-value>
 </context-param>

You can have multiple Servlets in an application. For example you might want to handle /secure/* requests in one way and /non-seucre/* in other way. For each of these Servlets you can have a context object, which is a WebApplicationContext.

<servlet>
    <servlet-name>SecureSpringDispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextClass</param-name>
        <param-value>com.myapp.secure.SecureContext</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <servlet-name>SecureSpringDispatcher</servlet-name>
    <url-pattern>/secure/*</url-pattern>
</servlet-mapping>
<servlet>
    <servlet-name>NonSecureSpringDispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextClass</param-name>
        <param-value>com.myapp.non-secure.NonSecureContext</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <servlet-name>NonSecureSpringDispatcher</servlet-name>
    <url-pattern>/non-secure/*</url-patten>
</servlet-mapping>

Call to a member function on a non-object

function page_properties($objPortal) {    
    $objPage->set_page_title($myrow['title']);
}

looks like different names of variables $objPortal vs $objPage

pypi UserWarning: Unknown distribution option: 'install_requires'

ATTENTION! ATTENTION! Imperfect answer ahead. To get the "latest memo" on the state of packaging in the Python universe, read this fairly detailed essay.

I have just ran into this problem when trying to build/install ansible. The problem seems to be that distutils really doesn't support install_requires. Setuptools should monkey-patch distutils on-the-fly, but it doesn't, probably because the last release of setuptools is 0.6c11 from 2009, whereas distutils is a core Python project.

So even after manually installing the setuptools-0.6c11-py2.7.egg running setup.py only picks up distutils dist.py, and not the one from site-packages/setuptools/.

Also the setuptools documentation hints to using ez_setup and not distutils.

However, setuptools is itself provided by distribute nowadays, and that flavor of setup() supports install_requires.

How can you program if you're blind?

I'm a postgraduate student in Beijing,China. I major in computer science and a lot of my work is programming. I am born with low sight, I need to use magnifying tools to see fonts on screen clearly. I use microsoft's mgnify tools on windows and use compiz's magnify plug in if on linux. I usally set the tool to magnify as three times many as the original font size. For me maginify tools is ok, the main problem is the speed,I have to move mouse to keep cursors follow the text I'm looking at, microsoft's magnify provides a option of "auto follow the text edit points",that set me from continuously mouse movement when editting or coding. But it doesn't always works because of the edit software or IDE may not support that. Magnifying tools on linux are hard to use. The KMag come with KDE has a terrible refresh rate which make my eyes unconfortable, compiz's magnifying plugs which I'm using now is OK,but has no function of auto focus(focus auto following). iOS provides quite perfect solution for me with full screen magnifying, especially on ipad's 9.7 inches screen. there auto focus is not necessary because I hardly use them to code or do other edit stuff. Android provides very little accessibility functions, only like shake feedback, which is useless for me. there is no any kind of good magnifying tools on android , not to mention advance function like full screen magnify on iOS. I used to study Qt, want to build a useful magnify tools on linux, even on android. But hardly have some progress.

Static class initializer in PHP

Actually, I use a public static method __init__() on my static classes that require initialization (or at least need to execute some code). Then, in my autoloader, when it loads a class it checks is_callable($class, '__init__'). If it is, it calls that method. Quick, simple and effective...

Enable UTF-8 encoding for JavaScript

The encoding for the page is not set correctly. Either add a header

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

or use set the appropriate http header.

Content-Type:text/html; charset=UTF-8

Firefox also allows you to change the encoding in View -> Character encoding.

If that's ok, I think javascript should handle UTF8 just fine.

How to disable text selection using jQuery?

This can easily be done using JavaScript This is applicable to all Browsers

<script type="text/javascript">

/***********************************************
* Disable Text Selection script- © Dynamic Drive DHTML code library (www.dynamicdrive.com)
* This notice MUST stay intact for legal use
* Visit Dynamic Drive at http://www.dynamicdrive.com/ for full source code
***********************************************/

function disableSelection(target){
if (typeof target.onselectstart!="undefined") //For IE 
    target.onselectstart=function(){return false}
else if (typeof target.style.MozUserSelect!="undefined") //For Firefox
    target.style.MozUserSelect="none"
else //All other route (For Opera)
    target.onmousedown=function(){return false}
target.style.cursor = "default"
}
 </script>

Call to this function

<script type="text/javascript">
   disableSelection(document.body)
</script>

Returning http 200 OK with error within response body

HTTP Is the Protocol handling the transmission of data over the internet.

If that transmission breaks for whatever reason the HTTP error codes tell you why it can't be sent to you.

The data being transmitted is not handled by HTTP Error codes. Only the method of transmission.

HTTP can't say 'Ok, this answer is gobbledigook, but here it is'. it just says 200 OK.

i.e : I've completed my job of getting it to you, the rest is up to you.

I know this has been answered already but I put it in words I can understand. sorry for any repetition.

Parse date without timezone javascript

(new Date().toString()).replace(/ \w+-\d+ \(.*\)$/,"")

This will have output: Tue Jul 10 2018 19:07:11

(new Date("2005-07-08T11:22:33+0000").toString()).replace(/ \w+-\d+ \(.*\)$/,"")

This will have output: Fri Jul 08 2005 04:22:33

Note: The time returned will depend on your local timezone

Listing files in a specific "folder" of a AWS S3 bucket

As other have already said, everything in S3 is an object. To you, it may be files and folders. But to S3, they're just objects.

If you don't need objects which end with a '/' you can safely delete them e.g. via REST api or AWS Java SDK (I assume you have write access). You will not lose "nested files" (there no files, so you will not lose objects whose names are prefixed with the key you delete)

AmazonS3 amazonS3 = AmazonS3ClientBuilder.standard().withCredentials(new ProfileCredentialsProvider()).withRegion("region").build();
amazonS3.deleteObject(new DeleteObjectRequest("my-bucket", "users/<user-id>/contacts/<contact-id>/"));

Please note that I'm using ProfileCredentialsProvider so that my requests are not anonymous. Otherwise, you will not be able to delete an object. I have my AWS keep key stored in ~/.aws/credentials file.

How can I inspect the file system of a failed `docker build`?

The top answer works in the case that you want to examine the state immediately prior to the failed command.

However, the question asks how to examine the state of the failed container itself. In my situation, the failed command is a build that takes several hours, so rewinding prior to the failed command and running it again takes a long time and is not very helpful.

The solution here is to find the container that failed:

$ docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                          PORTS               NAMES
6934ada98de6        42e0228751b3        "/bin/sh -c './utils/"   24 minutes ago      Exited (1) About a minute ago                       sleepy_bell

Commit it to an image:

$ docker commit 6934ada98de6
sha256:7015687976a478e0e94b60fa496d319cdf4ec847bcd612aecf869a72336e6b83

And then run the image [if necessary, running bash]:

$ docker run -it 7015687976a4 [bash -il]

Now you are actually looking at the state of the build at the time that it failed, instead of at the time before running the command that caused the failure.

Detect URLs in text with JavaScript

Function can be further improved to render images as well:

function renderHTML(text) { 
    var rawText = strip(text)
    var urlRegex =/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;   

    return rawText.replace(urlRegex, function(url) {   

    if ( ( url.indexOf(".jpg") > 0 ) || ( url.indexOf(".png") > 0 ) || ( url.indexOf(".gif") > 0 ) ) {
            return '<img src="' + url + '">' + '<br/>'
        } else {
            return '<a href="' + url + '">' + url + '</a>' + '<br/>'
        }
    }) 
} 

or for a thumbnail image that links to fiull size image:

return '<a href="' + url + '"><img style="width: 100px; border: 0px; -moz-border-radius: 5px; border-radius: 5px;" src="' + url + '">' + '</a>' + '<br/>'

And here is the strip() function that pre-processes the text string for uniformity by removing any existing html.

function strip(html) 
    {  
        var tmp = document.createElement("DIV"); 
        tmp.innerHTML = html; 
        var urlRegex =/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;   
        return tmp.innerText.replace(urlRegex, function(url) {     
        return '\n' + url 
    })
} 

Capturing browser logs with Selenium WebDriver using Java

A less elegant solution is taking the log 'manually' from the user data dir:

  1. Set the user data dir to a fixed place:

    options = new ChromeOptions();
    capabilities = DesiredCapabilities.chrome();
    options.addArguments("user-data-dir=/your_path/");
    capabilities.setCapability(ChromeOptions.CAPABILITY, options);
    
  2. Get the text from the log file chrome_debug.log located in the path you've entered above.

I use this method since RemoteWebDriver had problems getting the console logs remotely. If you run your test locally that can be easy to retrieve.

Using the "start" command with parameters passed to the started program

Put the command inside a batch file, and call that with the parameters.

Also, did you try this yet? (Move end quote to encapsulate parameters)

start "c:\program files\Microsoft Virtual PC\Virtual PC.exe -pc MY-PC -launch"

How to remove an id attribute from a div using jQuery?

The capitalization is wrong, and you have an extra argument.

Do this instead:

$('img#thumb').removeAttr('id');

For future reference, there aren't any jQuery methods that begin with a capital letter. They all take the same form as this one, starting with a lower case, and the first letter of each joined "word" is upper case.

Run a mySQL query as a cron job?

Try creating a shell script like the one below:

#!/bin/bash

mysql --user=[username] --password=[password] --database=[db name] --execute="DELETE FROM tbl_message WHERE DATEDIFF( NOW( ) ,  timestamp ) >=7"

You can then add this to the cron

Missing Microsoft RDLC Report Designer in Visual Studio

I had the same problem, after install the MS VS Community 2015, I didn't find the RDLC files neither the Report Viewer component, I solve the problem by going in the Control Panel (Windows) -> Programs -> Try to uninstall the MS VS Community and choose MODIFY, in this moment you will be able to Check the Microsoft SQL Server Data Tools.

That is it!

Faster way to zero memory than with memset?

There is one fatal flaw in this otherwise great and helpful test: As memset is the first instruction, there seems to be some "memory overhead" or so which makes it extremely slow. Moving the timing of memset to second place and something else to first place or simply timing memset twice makes memset the fastest with all compile switches!!!

How can I make a time delay in Python?

Delays can be also implemented by using the following methods.

The first method:

import time
time.sleep(5) # Delay for 5 seconds.

The second method to delay would be using the implicit wait method:

 driver.implicitly_wait(5)

The third method is more useful when you have to wait until a particular action is completed or until an element is found:

self.wait.until(EC.presence_of_element_located((By.ID, 'UserName'))

Traits vs. interfaces

Traits are simply for code reuse.

Interface just provides the signature of the functions that is to be defined in the class where it can be used depending on the programmer's discretion. Thus giving us a prototype for a group of classes.

For reference- http://www.php.net/manual/en/language.oop5.traits.php

How do I remove all non alphanumeric characters from a string except dash?

There is a much easier way with Regex.

private string FixString(string str)
{
    return string.IsNullOrEmpty(str) ? str : Regex.Replace(str, "[\\D]", "");
}

Copy entire directory contents to another directory?

public static void copyFolder(File source, File destination)
{
    if (source.isDirectory())
    {
        if (!destination.exists())
        {
            destination.mkdirs();
        }

        String files[] = source.list();

        for (String file : files)
        {
            File srcFile = new File(source, file);
            File destFile = new File(destination, file);

            copyFolder(srcFile, destFile);
        }
    }
    else
    {
        InputStream in = null;
        OutputStream out = null;

        try
        {
            in = new FileInputStream(source);
            out = new FileOutputStream(destination);

            byte[] buffer = new byte[1024];

            int length;
            while ((length = in.read(buffer)) > 0)
            {
                out.write(buffer, 0, length);
            }
        }
        catch (Exception e)
        {
            try
            {
                in.close();
            }
            catch (IOException e1)
            {
                e1.printStackTrace();
            }

            try
            {
                out.close();
            }
            catch (IOException e1)
            {
                e1.printStackTrace();
            }
        }
    }
}

JSON.Net Self referencing loop detected

for asp.net core 3.1.3 this worked for me

services.AddControllers().AddNewtonsoftJson(opt=>{
            opt.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
        });

How to set Java SDK path in AndroidStudio?

Go to File>Project Structure>JDK location: Here, you have to set the directory path exactly same, in which you have installed the java version. Also, you have to mention the paths of SDK for project run on emulator successfully.

Why This Problem Occurs: It is due to the unsynchronized java version directory that should be available to Android Studio for java code compilance.

Adding an onclick function to go to url in JavaScript?

function URL() {
    location.href = 'http://your.url.here';
}

Scale Image to fill ImageView width and keep aspect ratio

FOR IMAGE VIEW (set these parameters)

android:layout_width     = "match_parent"
android:layout_height    = "wrap_content"
android:scaleType        = "fitCenter"
android:adjustViewBounds = "true"

Now whatever the size of the image is there, it's width will match the parent and height will be according to match the ratio. I have tested this and I am 100% sure.

we want this --> adjustViewBound = true

not this --> adjustViewBound = false

// Results will be: 
Image width -> stretched as match parent
Image height -> according to image width (maximum to aspect ratio)

// like the first one

Android on-screen keyboard auto popping up

This code will work on all android versions:

@Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_login);

 //Automatic popping up keyboard on start Activity

     getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);

 or

 //avoid automatically appear android keyboard when activity start
     getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
 }

java.lang.UnsupportedClassVersionError: Unsupported major.minor version 51.0 (unable to load class frontend.listener.StartupListener)

What is your output when you do java -version? This will tell you what version the running JVM is.

The Unsupported major.minor version 51.0 error could mean:

  • Your server is running a lower Java version then the one used to compile your Servlet and vice versa

Either way, uninstall all JVM runtimes including JDK and download latest and re-install. That should fix any Unsupported major.minor error as you will have the lastest JRE and JDK (Maybe even newer then the one used to compile the Servlet)

See: http://www.java.com/en/download/manual.jsp (7 Update 25 )

and here: http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform (JDK) 7u25)

for the latest version of the JRE and JDK respectively.

EDIT:

Most likely your code was written in Java7 however maybe it was done using Java7update4 and your system is running Java7update3. Thus they both are effectively the same major version but the minor versions differ. Only the larger minor version is backward compatible with the lower minor version.

Edit 2 : If you have more than one jdk installed on your pc. you should check that Apache Tomcat is using the same one (jre) you are compiling your programs with. If you installed a new jdk after installing apache it normally won't select the new version.

Using Javamail to connect to Gmail smtp server ignores specified port and tries to use 25

Maybe useful for anyone else running into this issue: When setting the port on the properties:

props.put("mail.smtp.port", smtpPort);

..make sure to use a string object. Using a numeric (ie Long) object will cause this statement to seemingly have no effect.

How to get the Enum Index value in C#

In answering this question I define 'value' as the value of the enum item, and index as is positional location in the Enum definition (which is sorted by value). The OP's question asks for 'index' and various answer have interpreted this as either 'index' or 'value' (by my definitions). Sometimes the index is equal to numerical value.

No answer has specifically addressed the case of finding the index (not value) where the Enum is an Enum flag.

Enum Flag
{
    none = 0       // not a flag, thus index =-1
    A = 1 << 0,   // index should be 0
    B = 1 << 1,   // index should be 1 
    C = 1 << 2,   // index should be 2 
    D = 1 << 3,   // index should be 3,
    AandB = A | B // index is composite, thus index = -1 indicating undefined
    All = -1      //index is composite, thus index = -1 indicating undefined
}

In the case of Flag Enums, the index is simply given by

var index = (int)(Math.Log2((int)flag)); //Shows the maths, but is inefficient

However, the above solution is (a) Inefficient as pointed out by @phuclv (Math.Log2() is floating point and costly) and (b) Does not address the Flag.none case, nor any composite flags - flags that are composed of other flags (eg the 'AandB' flag as in my example).

DotNetCore If using dot net core we can address both a) and b) above as follows:

int setbits = BitOperations.PopCount((uint)flag); //get number of set bits
if (setbits != 1) //Finds ECalFlags.none, and all composite flags
    return -1;   //undefined index
int index = BitOperations.TrailingZeroCount((uint)flag); //Efficient bit operation

Not DotNetCore The BitOperations only work in dot net core. See @phuclv answer here for some efficient suggestions https://stackoverflow.com/a/63582586/6630192

  • @user1027167 answer will not work if composite flags are used, as per my comment on his answer
  • Thankyou to @phuclv for suggestions on improving efficiency

Threads vs Processes in Linux

I think everyone has done a great job responding to your question. I'm just adding more information about thread versus process in Linux to clarify and summarize some of the previous responses in context of kernel. So, my response is in regarding to kernel specific code in Linux. According to Linux Kernel documentation, there is no clear distinction between thread versus process except thread uses shared virtual address space unlike process. Also note, the Linux Kernel uses the term "task" to refer to process and thread in general.

"There are no internal structures implementing processes or threads, instead there is a struct task_struct that describe an abstract scheduling unit called task"

Also according to Linus Torvalds, you should NOT think about process versus thread at all and because it's too limiting and the only difference is COE or Context of Execution in terms of "separate the address space from the parent " or shared address space. In fact he uses a web server example to make his point here (which highly recommend reading).

Full credit to linux kernel documentation

.gitignore is ignored by Git

Without adding another commit to your project, one line will be enough to make .gitignore work as it is supposed to:

git rm -r --cached debug.log nbproject

This will remove them from the repository, but still keep them physically. In plain English, it deletes any history of changes related to them, and also will not track their change in any future commit. You may find a better explanation here.

return, return None, and no return at all?

Yes, they are all the same.

We can review the interpreted machine code to confirm that that they're all doing the exact same thing.

import dis

def f1():
  print "Hello World"
  return None

def f2():
  print "Hello World"
  return

def f3():
  print "Hello World"

dis.dis(f1)
    4   0 LOAD_CONST    1 ('Hello World')
        3 PRINT_ITEM
        4 PRINT_NEWLINE

    5   5 LOAD_CONST    0 (None)
        8 RETURN_VALUE

dis.dis(f2)
    9   0 LOAD_CONST    1 ('Hello World')
        3 PRINT_ITEM
        4 PRINT_NEWLINE

    10  5 LOAD_CONST    0 (None)
        8 RETURN_VALUE

dis.dis(f3)
    14  0 LOAD_CONST    1 ('Hello World')
        3 PRINT_ITEM
        4 PRINT_NEWLINE            
        5 LOAD_CONST    0 (None)
        8 RETURN_VALUE      

How to display Woocommerce product price by ID number on a custom page?

If you have the product's ID you can use that to create a product object:

$_product = wc_get_product( $product_id );

Then from the object you can run any of WooCommerce's product methods.

$_product->get_regular_price();
$_product->get_sale_price();
$_product->get_price();

Update
Please review the Codex article on how to write your own shortcode.

Integrating the WooCommerce product data might look something like this:

function so_30165014_price_shortcode_callback( $atts ) {
    $atts = shortcode_atts( array(
        'id' => null,
    ), $atts, 'bartag' );

    $html = '';

    if( intval( $atts['id'] ) > 0 && function_exists( 'wc_get_product' ) ){
         $_product = wc_get_product( $atts['id'] );
         $html = "price = " . $_product->get_price();
    }
    return $html;
}
add_shortcode( 'woocommerce_price', 'so_30165014_price_shortcode_callback' );

Your shortcode would then look like [woocommerce_price id="99"]

Commit only part of a file in Git

git gui provides this functionality under the diff view. Just right click the line(s) you're interested in and you should see a "stage this line to commit" menu item.

A 'for' loop to iterate over an enum in Java

More methods in java 8:

Using EnumSet with forEach

EnumSet.allOf(Direction.class).forEach(...);

Using Arrays.asList with forEach

Arrays.asList(Direction.values()).forEach(...);

How to add directory to classpath in an application run profile in IntelliJ IDEA?

Set "VM options" like: "-cp $Classpath$;your_classpath"

VM options

In laymans terms, what does 'static' mean in Java?

In addition to what @inkedmn has pointed out, a static member is at the class level. Therefore, the said member is loaded into memory by the JVM once for that class (when the class is loaded). That is, there aren't n instances of a static member loaded for n instances of the class to which it belongs.

Select All Rows Using Entity Framework

Entity Framework has one beautiful thing for it, like :

var users = context.Users; 

This will select all rows in Table User, then you can use your .ToList() etc.


For newbies to Entity Framework, it is like :

PortalEntities context = new PortalEntities();
var users = context.Users;

This will select all rows in Table User

What is a good Hash Function?

I'd say that the main rule of thumb is not to roll your own. Try to use something that has been thoroughly tested, e.g., SHA-1 or something along those lines.

Removing cordova plugins from the project

  • access the folder
  • list the plugins (cordova plugin list)
  • ionic cordova plugin remove "pluginName"

Should be fine!

How do I read from parameters.yml in a controller in symfony2?

In Symfony 4.3.1 I use this:

services.yaml

HTTP_USERNAME: 'admin'
HTTP_PASSWORD: 'password123'

FrontController.php

$username = $this->container->getParameter('HTTP_USERNAME');
$password = $this->container->getParameter('HTTP_PASSWORD');

Parsing command-line arguments in C

I am using getopt() under windows/mingw :

while ((c = getopt(myargc, myargv, "vp:d:rcx")) != -1) {
        switch (c) {
        case 'v': // print version
            printf("%s Version %s\n", myargv[0], VERSION);
            exit(0);
            break;
        case 'p': // change local port to listen to
            strncpy(g_portnum, optarg, 10);
            break;
...

SQL Query - how do filter by null or not null

set ansi_nulls off go select * from table t inner join otherTable o on t.statusid = o.statusid go set ansi_nulls on go

Unable to resolve "unable to get local issuer certificate" using git on Windows with self-signed certificate

Open Git Bash and run the command if you want to completely disable SSL verification.

git config --global http.sslVerify false

Note: This solution may open you to attacks like man-in-the-middle attacks. Therefore turn on verification again as soon as possible:

git config --global http.sslVerify true

How to convert all tables in database to one collation?

Better option to change also collation of varchar columns inside table also

SELECT CONCAT('ALTER TABLE `', TABLE_NAME,'` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;') AS    mySQL
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA= "myschema"
AND TABLE_TYPE="BASE TABLE"

Additionnaly if you have data with forein key on non utf8 column before launch the bunch script use

SET foreign_key_checks = 0;

It means global SQL will be for mySQL :

SET foreign_key_checks = 0;
ALTER TABLE `table1` CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;
ALTER TABLE `table2` CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;
ALTER TABLE `tableXXX` CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;
SET foreign_key_checks = 1;

But take care if according mysql documentation http://dev.mysql.com/doc/refman/5.1/en/charset-column.html,

If you use ALTER TABLE to convert a column from one character set to another, MySQL attempts to map the data values, but if the character sets are incompatible, there may be data loss. "

EDIT: Specially with column type enum, it just crash completly enums set (even if there is no special caracters) https://bugs.mysql.com/bug.php?id=26731

Select from multiple tables without a join?

You could try this notattion:

SELECT * from table1,table2 

More complicated one :

SELECT table1.field1,table1.field2, table2.field3,table2.field8 from table1,table2 where table1.field2 = something and table2.field3 = somethingelse

'str' object has no attribute 'decode'. Python 3 error?

This worked for me:

html.replace("\\/", "/").encode().decode('unicode_escape', 'surrogatepass')

This is similar to json.loads(html) behaviour

Where in an Eclipse workspace is the list of projects stored?

You can also have several workspaces - so you can connect to one and have set "A" of projects - and then connect to a different set when ever you like.

When are static variables initialized?

Static fields are initialized when the class is loaded by the class loader. Default values are assigned at this time. This is done in the order than they appear in the source code.

What's the right way to create a date in Java?

The excellent joda-time library is almost always a better choice than Java's Date or Calendar classes. Here's a few examples:

DateTime aDate = new DateTime(year, month, day, hour, minute, second);
DateTime anotherDate = new DateTime(anotherYear, anotherMonth, anotherDay, ...);
if (aDate.isAfter(anotherDate)) {...}
DateTime yearFromADate = aDate.plusYears(1);

Enter triggers button click

I don't think you need javascript or CSS to fix this.

According to the html 5 spec for buttons a button with no type attribute is treated the same as a button with its type set to "submit", i.e. as a button for submitting its containing form. Setting the button's type to "button" should prevent the behaviour you're seeing.

I'm not sure about browser support for this, but the same behaviour was specified in the html 4.01 spec for buttons so I expect it's pretty good.

What are named pipes?

According to Wikipedia:

[...] A traditional pipe is "unnamed" because it exists anonymously and persists only for as long as the process is running. A named pipe is system-persistent and exists beyond the life of the process and must be "unlinked" or deleted once it is no longer being used. Processes generally attach to the named pipe (usually appearing as a file) to perform IPC (inter-process communication).

How to change a css class style through Javascript?

Since classList is supported in all major browsers and jQuery drops support for IE<9 (in 2.x branch as Stormblack points in the comment), considering this HTML

<div id="mydiv" class="oldclass">text</div>

you can comfortably use this syntax:

document.getElementById('mydiv').classList.add("newClass");

This will also result in:

<div id="mydiv" class="oldclass newclass">text</div>

plus you can also use remove, toggle, contains methods.

Return the most recent record from ElasticSearch index

Since this question was originally asked and answered, some of the inner-workings of Elasticsearch have changed, particularly around timestamps. Here is a full example showing how to query for single latest record. Tested on ES 6/7.

1) Tell Elasticsearch to treat timestamp field as the timestamp

curl -XPUT "localhost:9200/my_index?pretty" -H 'Content-Type: application/json' -d '{"mappings":{"message":{"properties":{"timestamp":{"type":"date"}}}}}'

2) Put some test data into the index

curl -XPOST "localhost:9200/my_index/message/1" -H 'Content-Type: application/json' -d '{ "timestamp" : "2019-08-02T03:00:00Z", "message" : "hello world" }'
curl -XPOST "localhost:9200/my_index/message/2" -H 'Content-Type: application/json' -d '{ "timestamp" : "2019-08-02T04:00:00Z", "message" : "bye world" }'

3) Query for the latest record

curl -X POST "localhost:9200/my_index/_search" -H 'Content-Type: application/json' -d '{"query": {"match_all": {}},"size": 1,"sort": [{"timestamp": {"order": "desc"}}]}'

4) Expected results

{
   "took":0,
   "timed_out":false,
   "_shards":{
      "total":5,
      "successful":5,
      "skipped":0,
      "failed":0
   },
   "hits":{
      "total":2,
      "max_score":null,
      "hits":[
         {
            "_index":"my_index",
            "_type":"message",
            "_id":"2",
            "_score":null,
            "_source":{
               "timestamp":"2019-08-02T04:00:00Z",
               "message":"bye world"
            },
            "sort":[
               1564718400000
            ]
         }
      ]
   }
}

Compiling LaTex bib source

Just in case it helps someone, since these questions (and answers) helped me really much; I decided to create an alias that runs these 4 commands in a row:

Just add the following line to your ~/.bashrc file (modify the main keyword accordingly to the name of your .tex and .bib files)

alias texbib = 'pdflatex main.tex && bibtex main && pdflatex main.tex && pdflatex main.tex'

And now, by just executing the texbib command (alias), all these commands will be executed sequentially.

No increment operator (++) in Ruby?

From a posting by Matz:

(1) ++ and -- are NOT reserved operator in Ruby.

(2) C's increment/decrement operators are in fact hidden assignment. They affect variables, not objects. You cannot accomplish assignment via method. Ruby uses +=/-= operator instead.

(3) self cannot be a target of assignment. In addition, altering the value of integer 1 might cause severe confusion throughout the program.

                      matz.

Android Overriding onBackPressed()

You may just call the onBackPressed()and if you want some activity to display after the back button you have mention the

Intent intent = new Intent(ResetPinActivity.this, MenuActivity.class);
    startActivity(intent);
    finish();

that worked for me.

Center a H1 tag inside a DIV

You could add padding to the h1:

#AlertDiv h1 {
  padding:15px 18px;
}

Excel Macro - Select all cells with data and format as table

Try this one for current selection:

Sub A_SelectAllMakeTable2()
    Dim tbl As ListObject
    Set tbl = ActiveSheet.ListObjects.Add(xlSrcRange, Selection, , xlYes)
    tbl.TableStyle = "TableStyleMedium15"
End Sub

or equivalent of your macro (for Ctrl+Shift+End range selection):

Sub A_SelectAllMakeTable()
    Dim tbl As ListObject
    Dim rng As Range

    Set rng = Range(Range("A1"), Range("A1").SpecialCells(xlLastCell))
    Set tbl = ActiveSheet.ListObjects.Add(xlSrcRange, rng, , xlYes)
    tbl.TableStyle = "TableStyleMedium15"
End Sub

PHP sessions default timeout

http://php.net/session.gc-maxlifetime

session.gc_maxlifetime = 1440
(1440 seconds = 24 minutes)

Escape string Python for MySQL

{!a} applies ascii() and hence escapes non-ASCII characters like quotes and even emoticons. Here is an example

cursor.execute("UPDATE skcript set author='{!a}',Count='{:d}' where url='{!s}'".format(authors),leng,url))

Python3 docs

MySQL JOIN ON vs USING?

Database tables

To demonstrate how the USING and ON clauses work, let's assume we have the following post and post_comment database tables, which form a one-to-many table relationship via the post_id Foreign Key column in the post_comment table referencing the post_id Primary Key column in the post table:

SQL USING vs ON clauses table relationship

The parent post table has 3 rows:

| post_id | title     |
|---------|-----------|
| 1       | Java      |
| 2       | Hibernate |
| 3       | JPA       |

and the post_comment child table has the 3 records:

| post_comment_id | review    | post_id |
|-----------------|-----------|---------|
| 1               | Good      | 1       |
| 2               | Excellent | 1       |
| 3               | Awesome   | 2       |

The JOIN ON clause using a custom projection

Traditionally, when writing an INNER JOIN or LEFT JOIN query, we happen to use the ON clause to define the join condition.

For example, to get the comments along with their associated post title and identifier, we can use the following SQL projection query:

SELECT
   post.post_id,
   title,
   review
FROM post
INNER JOIN post_comment ON post.post_id = post_comment.post_id
ORDER BY post.post_id, post_comment_id

And, we get back the following result set:

| post_id | title     | review    |
|---------|-----------|-----------|
| 1       | Java      | Good      |
| 1       | Java      | Excellent |
| 2       | Hibernate | Awesome   |

The JOIN USING clause using a custom projection

When the Foreign Key column and the column it references have the same name, we can use the USING clause, like in the following example:

SELECT
  post_id,
  title,
  review
FROM post
INNER JOIN post_comment USING(post_id)
ORDER BY post_id, post_comment_id

And, the result set for this particular query is identical to the previous SQL query that used the ON clause:

| post_id | title     | review    |
|---------|-----------|-----------|
| 1       | Java      | Good      |
| 1       | Java      | Excellent |
| 2       | Hibernate | Awesome   |

The USING clause works for Oracle, PostgreSQL, MySQL, and MariaDB. SQL Server doesn't support the USING clause, so you need to use the ON clause instead.

The USING clause can be used with INNER, LEFT, RIGHT, and FULL JOIN statements.

SQL JOIN ON clause with SELECT *

Now, if we change the previous ON clause query to select all columns using SELECT *:

SELECT *
FROM post
INNER JOIN post_comment ON post.post_id = post_comment.post_id
ORDER BY post.post_id, post_comment_id

We are going to get the following result set:

| post_id | title     | post_comment_id | review    | post_id |
|---------|-----------|-----------------|-----------|---------|
| 1       | Java      | 1               | Good      | 1       |
| 1       | Java      | 2               | Excellent | 1       |
| 2       | Hibernate | 3               | Awesome   | 2       |

As you can see, the post_id is duplicated because both the post and post_comment tables contain a post_id column.

SQL JOIN USING clause with SELECT *

On the other hand, if we run a SELECT * query that features the USING clause for the JOIN condition:

SELECT *
FROM post
INNER JOIN post_comment USING(post_id)
ORDER BY post_id, post_comment_id

We will get the following result set:

| post_id | title     | post_comment_id | review    |
|---------|-----------|-----------------|-----------|
| 1       | Java      | 1               | Good      |
| 1       | Java      | 2               | Excellent |
| 2       | Hibernate | 3               | Awesome   |

You can see that this time, the post_id column is deduplicated, so there is a single post_id column being included in the result set.

Conclusion

If the database schema is designed so that Foreign Key column names match the columns they reference, and the JOIN conditions only check if the Foreign Key column value is equal to the value of its mirroring column in the other table, then you can employ the USING clause.

Otherwise, if the Foreign Key column name differs from the referencing column or you want to include a more complex join condition, then you should use the ON clause instead.

Creating watermark using html and css

To make it fixed: Try this way,

jsFiddleLink: http://jsfiddle.net/PERtY/

<div class="body">This is a sample body This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample bodyThis is a sample bodyThis is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    v
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    This is a sample body
    <div class="watermark">
           Sample Watermark
    </div>
    This is a sample body
    This is a sample bodyThis is a sample bodyThis is a sample body
</div>



.watermark {
    opacity: 0.5;
    color: BLACK;
    position: fixed;
    top: auto;
    left: 80%;
}

To use absolute:

.watermark {
    opacity: 0.5;
    color: BLACK;
    position: absolute;
    bottom: 0;
    right: 0;
}

jsFiddle: http://jsfiddle.net/6YSXC/

create a white rgba / CSS3

I believe

rgba( 0, 0, 0, 0.8 )

is equivalent in shade with #333.

Live demo: http://jsfiddle.net/8MVC5/1/

Parsing JSON using Json.net

I don't know about JSON.NET, but it works fine with JavaScriptSerializer from System.Web.Extensions.dll (.NET 3.5 SP1):

using System.Collections.Generic;
using System.Web.Script.Serialization;
public class NameTypePair
{
    public string OBJECT_NAME { get; set; }
    public string OBJECT_TYPE { get; set; }
}
public enum PositionType { none, point }
public class Ref
{
    public int id { get; set; }
}
public class SubObject
{
    public NameTypePair attributes { get; set; }
    public Position position { get; set; }
}
public class Position
{
    public int x { get; set; }
    public int y { get; set; }
}
public class Foo
{
    public Foo() { objects = new List<SubObject>(); }
    public string displayFieldName { get; set; }
    public NameTypePair fieldAliases { get; set; }
    public PositionType positionType { get; set; }
    public Ref reference { get; set; }
    public List<SubObject> objects { get; set; }
}
static class Program
{

    const string json = @"{
  ""displayFieldName"" : ""OBJECT_NAME"", 
  ""fieldAliases"" : {
    ""OBJECT_NAME"" : ""OBJECT_NAME"", 
    ""OBJECT_TYPE"" : ""OBJECT_TYPE""
  }, 
  ""positionType"" : ""point"", 
  ""reference"" : {
    ""id"" : 1111
  }, 
  ""objects"" : [
    {
      ""attributes"" : {
        ""OBJECT_NAME"" : ""test name"", 
        ""OBJECT_TYPE"" : ""test type""
      }, 
      ""position"" : 
      {
        ""x"" : 5, 
        ""y"" : 7
      }
    }
  ]
}";


    static void Main()
    {
        JavaScriptSerializer ser = new JavaScriptSerializer();
        Foo foo = ser.Deserialize<Foo>(json);
    }


}

Edit:

Json.NET works using the same JSON and classes.

Foo foo = JsonConvert.DeserializeObject<Foo>(json);

Link: Serializing and Deserializing JSON with Json.NET

TypeError: $ is not a function WordPress

I added a custom script file that loaded at the end of the head section, and inserted the following at the top:

(function (jQuery) {
    window.$ = jQuery.noConflict();
})(jQuery);

(This is a modification of Fanky's answer)

How to get the last value of an ArrayList

The following is part of the List interface (which ArrayList implements):

E e = list.get(list.size() - 1);

E is the element type. If the list is empty, get throws an IndexOutOfBoundsException. You can find the whole API documentation here.

How to prevent page scrolling when scrolling a DIV element?

here a simple solution without jQuery which does not destroy the browser native scroll (this is: no artificial/ugly scrolling):

var scrollable = document.querySelector('.scrollable');

scrollable.addEventListener('wheel', function(event) {
    var deltaY = event.deltaY;
    var contentHeight = scrollable.scrollHeight;
    var visibleHeight = scrollable.offsetHeight;
    var scrollTop = scrollable.scrollTop;

    if (scrollTop === 0 && deltaY < 0)
        event.preventDefault();
    else if (visibleHeight + scrollTop === contentHeight && deltaY > 0)
        event.preventDefault();
});

Live demo: http://jsfiddle.net/ibcaliax/bwmzfmq7/4/

How can I remove a specific item from an array?

Underscore.js can be used to solve issues with multiple browsers. It uses in-build browser methods if present. If they are absent like in the case of older Internet Explorer versions it uses its own custom methods.

A simple example to remove elements from array (from the website):

_.without([1, 2, 1, 0, 3, 1, 4], 0, 1); // => [2, 3, 4]

How to create the most compact mapping n ? isprime(n) up to a limit N?

Python 3:

def is_prime(a):
    return a > 1 and all(a % i for i in range(2, int(a**0.5) + 1))

Python reshape list to ndim array

The answers above are good. Adding a case that I used. Just if you don't want to use numpy and keep it as list without changing the contents.

You can run a small loop and change the dimension from 1xN to Nx1.

    tmp=[]
    for b in bus:
        tmp.append([b])
    bus=tmp

It is maybe not efficient while in case of very large numbers. But it works for a small set of numbers. Thanks

TypeError : Unhashable type

The real reason because set does not work is the fact, that it uses the hash function to distinguish different values. This means that sets only allows hashable objects. Why a list is not hashable is already pointed out.

Convert command line arguments into an array in Bash

Easier Yet, you can operate directly on $@ ;)

Here is how to do pass a a list of args directly from the prompt:

function echoarg { for stuff in "$@" ; do echo $stuff ; done ; } 
    echoarg Hey Ho Lets Go
    Hey
    Ho
    Lets
    Go

number_format() with MySQL

Antonio's answer

CONCAT(REPLACE(FORMAT(number,0),',','.'),',',SUBSTRING_INDEX(FORMAT(number,2),'.',-1))

is wrong; it may produce incorrect results!

For example, if "number" is 12345.67, the resulting string would be:

'12.346,67'

instead of

'12.345,67'

because FORMAT(number,0) rounds "number" up if fractional part is greater or equal than 0.5 (as it is in my example)!

What you COULD use is

CONCAT(REPLACE(FORMAT(FLOOR(number),0),',','.'),',',SUBSTRING_INDEX(FORMAT(number,2),'.',-1))

if your MySQL/MariaDB's FORMAT doesn't support "locale_name" (see MindStalker's post - Thx 4 that, pal). Note the FLOOR function I've added.

Display an array in a readable/hierarchical format

Instead of

print_r($data);

try

print "<pre>";
print_r($data);
print "</pre>";

Is there a function to copy an array in C/C++?

You can use the memcpy(),

void * memcpy ( void * destination, const void * source, size_t num );

memcpy() copies the values of num bytes from the location pointed by source directly to the memory block pointed by destination.

If the destination and source overlap, then you can use memmove().

void * memmove ( void * destination, const void * source, size_t num );

memmove() copies the values of num bytes from the location pointed by source to the memory block pointed by destination. Copying takes place as if an intermediate buffer were used, allowing the destination and source to overlap.

What is causing ImportError: No module named pkg_resources after upgrade of Python on os X?

I encountered the same ImportError. Somehow the setuptools package had been deleted in my Python environment.

To fix the issue, run the setup script for setuptools:

curl https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py | python

If you have any version of distribute, or any setuptools below 0.6, you will have to uninstall it first.*

See Installation Instructions for further details.


* If you already have a working distribute, upgrading it to the "compatibility wrapper" that switches you over to setuptools is easier. But if things are already broken, don't try that.

How can I fix MySQL error #1064?

For my case, I was trying to execute procedure code in MySQL, and due to some issue with server in which Server can't figure out where to end the statement I was getting Error Code 1064. So I wrapped the procedure with custom DELIMITER and it worked fine.

For example, Before it was:

DROP PROCEDURE IF EXISTS getStats;
CREATE PROCEDURE `getStats` (param_id INT, param_offset INT, param_startDate datetime, param_endDate datetime)
BEGIN
    /*Procedure Code Here*/
END;

After putting DELIMITER it was like this:

DROP PROCEDURE IF EXISTS getStats;
DELIMITER $$
CREATE PROCEDURE `getStats` (param_id INT, param_offset INT, param_startDate datetime, param_endDate datetime)
BEGIN
    /*Procedure Code Here*/
END;
$$
DELIMITER ;

Url.Action parameters?

The following is the correct overload (in your example you are missing a closing } to the routeValues anonymous object so your code will throw an exception):

<a href="<%: Url.Action("GetByList", "Listing", new { name = "John", contact = "calgary, vancouver" }) %>">
    <span>People</span>
</a>

Assuming you are using the default routes this should generate the following markup:

<a href="/Listing/GetByList?name=John&amp;contact=calgary%2C%20vancouver">
    <span>People</span>
</a>

which will successfully invoke the GetByList controller action passing the two parameters:

public ActionResult GetByList(string name, string contact) 
{
    ...
}

Python: How to increase/reduce the fontsize of x and y tick labels?

One shouldn't use set_yticklabels to change the fontsize, since this will also set the labels (i.e. it will replace any automatic formatter by a FixedFormatter), which is usually undesired. The easiest is to set the respective tick_params:

ax.tick_params(axis="x", labelsize=8)
ax.tick_params(axis="y", labelsize=20)

or

ax.tick_params(labelsize=8)

in case both axes shall have the same size.

Of course using the rcParams as in @tmdavison's answer is possible as well.

When should the xlsm or xlsb formats be used?

One could think that xlsb has only advantages over xlsm. The fact that xlsm is XML-based and xlsb is binary is that when workbook corruption occurs, you have better chances to repair a xlsm than a xlsb.

error: resource android:attr/fontVariationSettings not found

after upgrading to Android 3.4.2 and FTC SDK5.2. I got these errors when building APK:

Android resource linking failed C:\Users\idsid\FTC\SkyStone\TeamCode\build\intermediates\incremental\mergeDebugResources\merged.dir\values\values.xml:1205: error: resource android:attr/fontVariationSettings not found. C:\Users\idsid\FTC\SkyStone\TeamCode\build\intermediates\incremental\mergeDebugResources\merged.dir\values\values.xml:1206: error: resource android:attr/ttcIndex not found. error: failed linking references.

What I did is to add following section to project build gradle and problem is fixed.

subprojects {
    afterEvaluate {project ->
        if (project.hasProperty("android")) {
            android {
                compileSdkVersion 28
                buildToolsVersion '29.0.2'
            }
        }
    }
}

Good luck.

Self-reference for cell, column and row in worksheet functions

Just for row, but try referencing a cell just below the selected cell and subtracting one from row.

=ROW(A2)-1

Yields the Row of cell A1 (This formula would go in cell A1.

This avoids all the indirect() and index() use but still works.

Ignore case in Python strings

You could subclass str and create your own case-insenstive string class but IMHO that would be extremely unwise and create far more trouble than it's worth.

Qt: resizing a QLabel containing a QPixmap while keeping its aspect ratio

The Qt documentations has an Image Viewer example which demonstrates handling resizing images inside a QLabel. The basic idea is to use QScrollArea as a container for the QLabel and if needed use label.setScaledContents(bool) and scrollarea.setWidgetResizable(bool) to fill available space and/or ensure QLabel inside is resizable. Additionally, to resize QLabel while honoring aspect ratio use:

label.setPixmap(pixmap.scaled(width, height, Qt::KeepAspectRatio, Qt::FastTransformation));

The width and height can be set based on scrollarea.width() and scrollarea.height(). In this way there is no need to subclass QLabel.

How to set back button text in Swift

You can just modify the NavigationItem in the storyboard

enter image description here

In the Back Button add a space and press Enter.

Note: Do this in the previous VC.

Resizing an image in an HTML5 canvas

This is a javascript function adapted from @Telanor's code. When passing a image base64 as first argument to the function, it returns the base64 of the resized image. maxWidth and maxHeight are optional.

function thumbnail(base64, maxWidth, maxHeight) {

  // Max size for thumbnail
  if(typeof(maxWidth) === 'undefined') var maxWidth = 500;
  if(typeof(maxHeight) === 'undefined') var maxHeight = 500;

  // Create and initialize two canvas
  var canvas = document.createElement("canvas");
  var ctx = canvas.getContext("2d");
  var canvasCopy = document.createElement("canvas");
  var copyContext = canvasCopy.getContext("2d");

  // Create original image
  var img = new Image();
  img.src = base64;

  // Determine new ratio based on max size
  var ratio = 1;
  if(img.width > maxWidth)
    ratio = maxWidth / img.width;
  else if(img.height > maxHeight)
    ratio = maxHeight / img.height;

  // Draw original image in second canvas
  canvasCopy.width = img.width;
  canvasCopy.height = img.height;
  copyContext.drawImage(img, 0, 0);

  // Copy and resize second canvas to first canvas
  canvas.width = img.width * ratio;
  canvas.height = img.height * ratio;
  ctx.drawImage(canvasCopy, 0, 0, canvasCopy.width, canvasCopy.height, 0, 0, canvas.width, canvas.height);

  return canvas.toDataURL();

}

CSS Selector that applies to elements with two classes

Chain both class selectors (without a space in between):

.foo.bar {
    /* Styles for element(s) with foo AND bar classes */
}

If you still have to deal with ancient browsers like IE6, be aware that it doesn't read chained class selectors correctly: it'll only read the last class selector (.bar in this case) instead, regardless of what other classes you list.

To illustrate how other browsers and IE6 interpret this, consider this CSS:

* {
    color: black;
}

.foo.bar {
    color: red;
}

Output on supported browsers is:

<div class="foo">Hello Foo</div>       <!-- Not selected, black text [1] -->
<div class="foo bar">Hello World</div> <!-- Selected, red text [2] -->
<div class="bar">Hello Bar</div>       <!-- Not selected, black text [3] -->

Output on IE6 is:

<div class="foo">Hello Foo</div>       <!-- Not selected, black text [1] -->
<div class="foo bar">Hello World</div> <!-- Selected, red text [2] -->
<div class="bar">Hello Bar</div>       <!-- Selected, red text [2] -->

Footnotes:

  • Supported browsers:
    1. Not selected as this element only has class foo.
    2. Selected as this element has both classes foo and bar.
    3. Not selected as this element only has class bar.

  • IE6:
    1. Not selected as this element doesn't have class bar.
    2. Selected as this element has class bar, regardless of any other classes listed.

Show Current Location and Update Location in MKMapView in Swift

Hi Sometimes setting the showsUserLocation in code doesn't work for some weird reason.

So try a combination of the following.

In viewDidLoad()

  self.mapView.showsUserLocation = true

Go to your storyboard in Xcode, on the right panel's attribute inspector tick the User location check box, like in the attached image. run your app and you should be able to see the User location

enter image description here

Downloading jQuery UI CSS from Google's CDN

Google is hosting jQueryUI css at this link https://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery.ui.all.css

If you look at this code directly, it is importing the css using @import which can be slow. You may want to factor the import into its parts to gain a slight performance benefit:

https://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery.ui.base.css https://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery.ui.theme.css

Why do I get permission denied when I try use "make" to install something?

I had a very similar error message as you, although listing a particular file:

$ make
make: execvp: ../HoughLineExtractor/houghlineextractor.hh: Permission denied
make: *** [../HoughLineAccumulator/houghlineaccumulator.o] Error 127

$ sudo make
make: execvp: ../HoughLineExtractor/houghlineextractor.hh: Permission denied
make: *** [../HoughLineAccumulator/houghlineaccumulator.o] Error 127

In my case, I forgot to add a trailing slash to indicate continuation of the line as shown:

${LINEDETECTOR_OBJECTS}:\
    ../HoughLineAccumulator/houghlineaccumulator.hh  # <-- missing slash!!
    ../HoughLineExtractor/houghlineextractor.hh

Hope that helps someone else who lands here from a search engine.

How to get coordinates of an svg element?

I use the consolidate function, like so:

 element.transform.baseVal.consolidate()

The .e and .f values correspond to the x and y coordinates

Cross-Origin Request Blocked

You need other headers, not only access-control-allow-origin. If your request have the "Access-Control-Allow-Origin" header, you must copy it into the response headers, If doesn't, you must check the "Origin" header and copy it into the response. If your request doesn't have Access-Control-Allow-Origin not Origin headers, you must return "*".

You can read the complete explanation here: http://www.html5rocks.com/en/tutorials/cors/#toc-adding-cors-support-to-the-server

and this is the function I'm using to write cross domain headers:

func writeCrossDomainHeaders(w http.ResponseWriter, req *http.Request) {
    // Cross domain headers
    if acrh, ok := req.Header["Access-Control-Request-Headers"]; ok {
        w.Header().Set("Access-Control-Allow-Headers", acrh[0])
    }
    w.Header().Set("Access-Control-Allow-Credentials", "True")
    if acao, ok := req.Header["Access-Control-Allow-Origin"]; ok {
        w.Header().Set("Access-Control-Allow-Origin", acao[0])
    } else {
        if _, oko := req.Header["Origin"]; oko {
            w.Header().Set("Access-Control-Allow-Origin", req.Header["Origin"][0])
        } else {
            w.Header().Set("Access-Control-Allow-Origin", "*")
        }
    }
    w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE")
    w.Header().Set("Connection", "Close")

}

How can I clear or empty a StringBuilder?

delete is not overly complicated :

myStringBuilder.delete(0, myStringBuilder.length());

You can also do :

myStringBuilder.setLength(0);

The tilde operator in Python

It is a unary operator (taking a single argument) that is borrowed from C, where all data types are just different ways of interpreting bytes. It is the "invert" or "complement" operation, in which all the bits of the input data are reversed.

In Python, for integers, the bits of the twos-complement representation of the integer are reversed (as in b <- b XOR 1 for each individual bit), and the result interpreted again as a twos-complement integer. So for integers, ~x is equivalent to (-x) - 1.

The reified form of the ~ operator is provided as operator.invert. To support this operator in your own class, give it an __invert__(self) method.

>>> import operator
>>> class Foo:
...   def __invert__(self):
...     print 'invert'
...
>>> x = Foo()
>>> operator.invert(x)
invert
>>> ~x
invert

Any class in which it is meaningful to have a "complement" or "inverse" of an instance that is also an instance of the same class is a possible candidate for the invert operator. However, operator overloading can lead to confusion if misused, so be sure that it really makes sense to do so before supplying an __invert__ method to your class. (Note that byte-strings [ex: '\xff'] do not support this operator, even though it is meaningful to invert all the bits of a byte-string.)

Inserting an item in a Tuple

For the case where you are not adding to the end of the tuple

>>> a=(1,2,3,5,6)
>>> a=a[:3]+(4,)+a[3:]
>>> a
(1, 2, 3, 4, 5, 6)
>>> 

Get host domain from URL?

 var url = Regex.Match(url, @"(http:|https:)\/\/(.*?)\/");

INPUT = "https://stackoverflow.com/questions/";

OUTPUT = "https://stackoverflow.com/";

HTML-5 date field shows as "mm/dd/yyyy" in Chrome, even when valid date is set

I was having the same problem, with a value like 2016-08-8, then I solved adding a zero to have two digits days, and it works. Tested in chrome, firefox, and Edge

today:function(){
   var today = new Date();
   var d = (today.getDate() < 10 ? '0' : '' )+ today.getDate();
   var m = ((today.getMonth() + 1) < 10 ? '0' :'') + (today.getMonth() + 1);
   var y = today.getFullYear();
   var x = String(y+"-"+m+"-"+d); 
   return x;
}

HashSet vs LinkedHashSet

HashSet:

The underlined data structure is Hashtable. Duplicate objects are not allowed.insertion order is not preserved and it is based on hash code of objects. Null insertion is possible(only once). It implements Serializable, Clonable but not RandomAccess interface. HashSet is best choose if frequent operation is search operation.

In HashSet duplicates are not allowed.if users are trying to insert duplicates when we won't get any compile or runtime exceptions. add method returns simply false.

Constructors:

HashSet h=new HashSet(); creates an empty HashSet object with default initial capacity 16 and default fill ratio(Load factor) is 0.75 .

HashSet h=new HashSet(int initialCapacity); creates an empty HashSet object with specified initialCapacity and default fill ration is 0.75.

HashSet h=new HashSet(int initialCapacity, float fillRatio);

HashSet h=new HashSet(Collection c); creates an equivalent HashSet object for the given collection. This constructor meant for inter conversion between collection object.

LinkedHashSet:

It is a child class of HashSet. it is exactly same as HashSet including(Constructors and Methods) except the following differences.

Differences HashSet:

  1. The underlined data structure is Hashtable.
  2. Insertion order is not preserved.
  3. introduced 1.2 version.

LinkedHashSet:

  1. The underlined data structure is a combination of LinkedList and Hashtable.
  2. Insertion order is preserved.
  3. Indroduced in 1.4 version.

Difference between File.separator and slash in paths

With the Java libraries for dealing with files, you can safely use / (slash, not backslash) on all platforms. The library code handles translating things into platform-specific paths internally.

You might want to use File.separator in UI, however, because it's best to show people what will make sense in their OS, rather than what makes sense to Java.

Update: I have not been able, in five minutes of searching, to find the "you can always use a slash" behavior documented. Now, I'm sure I've seen it documented, but in the absense of finding an official reference (because my memory isn't perfect), I'd stick with using File.separator because you know that will work.

MySQL's now() +1 day

INSERT INTO `table` ( `data` , `date` ) VALUES('".$data."',NOW()+INTERVAL 1 DAY);

MySQL - ignore insert error: duplicate entry

You can make sure that you do not insert duplicate information by using the EXISTS condition.

For example, if you had a table named clients with a primary key of client_id, you could use the following statement:

INSERT INTO clients
(client_id, client_name, client_type)
SELECT supplier_id, supplier_name, 'advertising'
FROM suppliers
WHERE not exists (select * from clients
where clients.client_id = suppliers.supplier_id);

This statement inserts multiple records with a subselect.

If you wanted to insert a single record, you could use the following statement:

INSERT INTO clients
(client_id, client_name, client_type)
SELECT 10345, 'IBM', 'advertising'
FROM dual
WHERE not exists (select * from clients
where clients.client_id = 10345);

The use of the dual table allows you to enter your values in a select statement, even though the values are not currently stored in a table.

from http://www.techonthenet.com/sql/insert.php

Doctrine2: Best way to handle many-to-many with extra columns in reference table

I've opened a similar question in the Doctrine user mailing list and got a really simple answer;

consider the many to many relation as an entity itself, and then you realize you have 3 objects, linked between them with a one-to-many and many-to-one relation.

http://groups.google.com/group/doctrine-user/browse_thread/thread/d1d87c96052e76f7/436b896e83c10868#436b896e83c10868

Once a relation has data, it's no more a relation !

Seeking useful Eclipse Java code templates

slf4j Logging

${imp:import(org.slf4j.Logger,org.slf4j.LoggerFactory)}

private static final Logger LOGGER = LoggerFactory
    .getLogger(${enclosing_type}.class);

How do I install the ext-curl extension with PHP 7?

I got an error that the CURL extension was missing whilst installing WebMail Lite 8 on WAMP (so on Windows).

After reading that libeay32.dll was required which was only present in some of the PHP installation folders (such as 7.1.26), I switched the PHP version in use from 7.2.14 to 7.1.26 in the WAMP PHP version menu, and the error went away.

Force DOM redraw/refresh on Chrome/Mac

CSS only. This works for situations where a child element is removed or added. In these situations, borders and rounded corners can leave artifacts.

el:after { content: " "; }
el:before { content: " "; }

Detect if an input has text in it using CSS -- on a page I am visiting and do not control?

Using JS and CSS :not pseudoclass

_x000D_
_x000D_
 input {_x000D_
        font-size: 13px;_x000D_
        padding: 5px;_x000D_
        width: 100px;_x000D_
    }_x000D_
_x000D_
    input[value=""] {_x000D_
        border: 2px solid #fa0000;_x000D_
    }_x000D_
_x000D_
    input:not([value=""]) {_x000D_
        border: 2px solid #fafa00;_x000D_
    }
_x000D_
<input type="text" onkeyup="this.setAttribute('value', this.value);" value="" />_x000D_
_x000D_
   
_x000D_
_x000D_
_x000D_

How to find which views are using a certain table in SQL Server (2008)?

This should do it:

SELECT * 
FROM   INFORMATION_SCHEMA.VIEWS 
WHERE  VIEW_DEFINITION like '%YourTableName%'

How to get images in Bootstrap's card to be the same height/width?

I solved this problem using Bootstrap 4 Emdeds Utilities

https://getbootstrap.com/docs/4.3/utilities/embed

In this case you just need to add you image to a div.embbed-responsive like this:

<div class="card">
  <div class="embed-responsive embed-responsive-16by9">
     <img alt="Card image cap" class="card-img-top embed-responsive-item" src="img/butterPecan.jpg" />
  </div>
  <div class="card-block">
    <h4 class="card-title">Butter Pecan</h4>
    <p class="card-text">Roasted pecans, butter and vanilla come together to make this wonderful ice cream</p>
  </div>
</div>

All images will fit the ratio specified by modifier classes:

  • .embed-responsive-21by9
  • .embed-responsive-16by9
  • .embed-responsive-4by3
  • .embed-responsive-1by1

Aditionally this css enables zoom instead of image stretching

.embed-responsive .card-img-top {
    object-fit: cover;
}

What are .iml files in Android Studio?

Those files are created and used by Android Studio editor.

You don't need to check in those files to version control.

Git uses .gitignore file, that contains list of files and directories, to know the list of files and directories that don't need to be checked in.

Android studio automatically creates .gitingnore files listing all files and directories which don't need to be checked in to any version control.

How disable / remove android activity label and label bar?

public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  

        //set up notitle 
        requestWindowFeature(Window.FEATURE_NO_TITLE);  
        //set up full screen
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,   
                WindowManager.LayoutParams.FLAG_FULLSCREEN);  

        setContentView(R.layout.main);  
} 

Replacing .NET WebBrowser control with a better browser, like Chrome?

You can use registry to set IE version for webbrowser control. Go to: HKLM\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION and add "yourApplicationName.exe" with value of browser_emulation To see value of browser_emulation, refer link: http://msdn.microsoft.com/en-us/library/ee330730%28VS.85%29.aspx#browser_emulation

Android: How to turn screen on and off programmatically?

Hi I hope this will help:

 private PowerManager mPowerManager;
 private PowerManager.WakeLock mWakeLock;

 public void turnOnScreen(){
     // turn on screen
     Log.v("ProximityActivity", "ON!");
     mWakeLock = mPowerManager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP, "tag");
     mWakeLock.acquire();
}

 @TargetApi(21) //Suppress lint error for PROXIMITY_SCREEN_OFF_WAKE_LOCK
 public void turnOffScreen(){
     // turn off screen
     Log.v("ProximityActivity", "OFF!");
     mWakeLock = mPowerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, "tag");
     mWakeLock.acquire();
}

Django: How can I call a view function from template?

For example, a logout button can be written like this:

<button class="btn btn-primary" onclick="location.href={% url 'logout'%}">Logout</button>

Where logout endpoint:

#urls.py:
url(r'^logout/$', auth_views.logout, {'next_page': '/'}, name='logout'),

Basic authentication with fetch?

A solution without dependencies.

Node

headers.set('Authorization', 'Basic ' + Buffer.from(username + ":" + password).toString('base64'));

Browser

headers.set('Authorization', 'Basic ' + btoa(username + ":" + password));

adb command for getting ip address assigned by operator

Try this command for Version <= Marshmallow,

adb devices

List of devices attached 38ccdc87 device

adb tcpip 5555

restarting in TCP mode port: 5555

adb shell ip addr show wlan0

24: wlan0: mtu 1500 qdisc mq state UP qlen 1000 link/ether ac:c1:ee:6b:22:f1 brd ff:ff:ff:ff:ff:ff inet 192.168.0.18/24 brd 192.168.0.255 scope global wlan0 valid_lft forever preferred_lft forever inet6 fd01::1d45:6b7a:a3b:5f4d/64 scope global temporary dynamic valid_lft 287sec preferred_lft 287sec inet6 fd01::aec1:eeff:fe6b:22f1/64 scope global dynamic valid_lft 287sec preferred_lft 287sec inet6 fe80::aec1:eeff:fe6b:22f1/64 scope link valid_lft forever preferred_lft forever

To connect to your device run this

adb connect 192.168.0.18

connected to 192.168.0.18:5555

Make sure you have adb inside this location android-sdk\platform-tools

Check if a time is between two times (time DataType)

select * from dbMaster oMaster  where ((CAST(GETDATE() as time)) between  (CAST(oMaster.DateFrom as time))  and  
(CAST(oMaster.DateTo as time)))

Please check this

Align div with fixed position on the right side

Use the 'right' attribute alongside fixed position styling. The value provided acts as an offset from the right of the window boundary.

Code example:

.test {
  position: fixed;
  right: 0;
}

If you need some padding you can set right property with a certain value, for example: right: 10px.

Note: float property doesn't work for position fixed and absolute

Vue.js unknown custom element

This is a good way to create a component in vue.

let template = `<ul>
  <li>Your data here</li>
</ul>`;

Vue.component('my-task', {
  template: template,
  data() {

  },
  props: {
    task: {
      type: String
    }
  },
  methods: {

  },
  computed: {

  },
  ready() {

  }
});

new Vue({
 el : '#app'
});

bind/unbind service example (android)

You can try using this code:

protected ServiceConnection mServerConn = new ServiceConnection() {
    @Override
    public void onServiceConnected(ComponentName name, IBinder binder) {
        Log.d(LOG_TAG, "onServiceConnected");
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        Log.d(LOG_TAG, "onServiceDisconnected");
    }
}

public void start() {
    // mContext is defined upper in code, I think it is not necessary to explain what is it 
    mContext.bindService(intent, mServerConn, Context.BIND_AUTO_CREATE);
    mContext.startService(intent);
}

public void stop() {
    mContext.stopService(new Intent(mContext, ServiceRemote.class));
    mContext.unbindService(mServerConn);
}

How do I find which process is leaking memory?

In addition to top, you can use System Monitor (System - Administration - System Monitor, then select Processes tab). Select View - All Processes, go to Edit - Preferences and enable Virtual Memory column. Sort either by this column, or by Memory column

angular2: how to copy object into another object

Loadsh is the universal standard library for coping any object deepcopy. It's a recursive algorithm. It's check everything and does copy for the given object. Writing this kind of algorithm will take longer time. It's better to leverage the same.

Array[n] vs Array[10] - Initializing array with variable vs real number

In C++, variable length arrays are not legal. G++ allows this as an "extension" (because C allows it), so in G++ (without being -pedantic about following the C++ standard), you can do:

int n = 10;
double a[n]; // Legal in g++ (with extensions), illegal in proper C++

If you want a "variable length array" (better called a "dynamically sized array" in C++, since proper variable length arrays aren't allowed), you either have to dynamically allocate memory yourself:

int n = 10;
double* a = new double[n]; // Don't forget to delete [] a; when you're done!

Or, better yet, use a standard container:

int n = 10;
std::vector<double> a(n); // Don't forget to #include <vector>

If you still want a proper array, you can use a constant, not a variable, when creating it:

const int n = 10;
double a[n]; // now valid, since n isn't a variable (it's a compile time constant)

Similarly, if you want to get the size from a function in C++11, you can use a constexpr:

constexpr int n()
{
    return 10;
}

double a[n()]; // n() is a compile time constant expression

Can I use if (pointer) instead of if (pointer != NULL)?

Question is answered, but I would like to add my points.

I will always prefer if(pointer) instead of if(pointer != NULL) and if(!pointer) instead of if(pointer == NULL):

  • It is simple, small
  • Less chances to write a buggy code, suppose if I misspelled equality check operator == with =
    if(pointer == NULL) can be misspelled if(pointer = NULL) So I will avoid it, best is just if(pointer).
    (I also suggested some Yoda condition in one answer, but that is diffrent matter)

  • Similarly for while (node != NULL && node->data == key), I will simply write while (node && node->data == key) that is more obvious to me (shows that using short-circuit).

  • (may be stupid reason) Because NULL is a macro, if suppose some one redefine by mistake with other value.

Android View shadow

I'm using Android Studio 0.8.6 and I couldn't find:

android:background="@drawable/abc_menu_dropdown_panel_holo_light"

so I found this instead:

android:background="@android:drawable/dialog_holo_light_frame"

and it looks like this:

enter image description here

Passing in class names to react components

With React 16.6.3 and @Material UI 3.5.1, I am using arrays in className like className={[classes.tableCell, classes.capitalize]}

Try something like the following in your case.

class Pill extends React.Component {
    render() {
        return (
           <button className={['pill', this.props.styleName]}>{this.props.children}</button>
        );
    }
}

Custom method names in ASP.NET Web API

I am days into the MVC4 world.

For what its worth, I have a SitesAPIController, and I needed a custom method, that could be called like:

http://localhost:9000/api/SitesAPI/Disposition/0

With different values for the last parameter to get record with different dispositions.

What Finally worked for me was:

The method in the SitesAPIController:

// GET api/SitesAPI/Disposition/1
[ActionName("Disposition")]
[HttpGet]
public Site Disposition(int disposition)
{
    Site site = db.Sites.Where(s => s.Disposition == disposition).First();
    return site;
}

And this in the WebApiConfig.cs

// this was already there
config.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

// this i added
config.Routes.MapHttpRoute(
    name: "Action",
    routeTemplate: "api/{controller}/{action}/{disposition}"
 );

For as long as I was naming the {disposition} as {id} i was encountering:

{
"Message": "No HTTP resource was found that matches the request URI 'http://localhost:9000/api/SitesAPI/Disposition/0'.",
"MessageDetail": "No action was found on the controller 'SitesAPI' that matches the request."
}

When I renamed it to {disposition} it started working. So apparently the parameter name is matched with the value in the placeholder.

Feel free to edit this answer to make it more accurate/explanatory.

Android How to adjust layout in Full Screen Mode when softkeyboard is visible

Just keep as android:windowSoftInputMode="adjustResize". Because it is given to keep only one out of "adjustResize" and "adjustPan"(The window adjustment mode is specified with either adjustResize or adjustPan. It is highly recommended that you always specify one or the other). You can find it out here: http://developer.android.com/resources/articles/on-screen-inputs.html

It works perfectly for me.

How to list physical disks?

I've modified an open-source program called "dskwipe" in order to pull this disk information out of it. Dskwipe is written in C, and you can pull this function out of it. The binary and source are available here: dskwipe 0.3 has been released

The returned information will look something like this:

Device Name                         Size Type      Partition Type
------------------------------ --------- --------- --------------------
\\.\PhysicalDrive0               40.0 GB Fixed
\\.\PhysicalDrive1               80.0 GB Fixed
\Device\Harddisk0\Partition0     40.0 GB Fixed
\Device\Harddisk0\Partition1     40.0 GB Fixed     NTFS
\Device\Harddisk1\Partition0     80.0 GB Fixed
\Device\Harddisk1\Partition1     80.0 GB Fixed     NTFS
\\.\C:                           80.0 GB Fixed     NTFS
\\.\D:                            2.1 GB Fixed     FAT32
\\.\E:                           40.0 GB Fixed     NTFS

"Cloning" row or column vectors

Use numpy.tile:

>>> tile(array([1,2,3]), (3, 1))
array([[1, 2, 3],
       [1, 2, 3],
       [1, 2, 3]])

or for repeating columns:

>>> tile(array([[1,2,3]]).transpose(), (1, 3))
array([[1, 1, 1],
       [2, 2, 2],
       [3, 3, 3]])

Android: java.lang.SecurityException: Permission Denial: start Intent

It's easy maybe you have error in the configuration.

For Example: Manifest.xml

enter image description here

But in my configuration have for default Activity .Splash

enter image description here

you need check this configuration and the file Manifest.xml

Good Luck

How do I select and store columns greater than a number in pandas?

Sample DF:

In [79]: df = pd.DataFrame(np.random.randint(5, 15, (10, 3)), columns=list('abc'))

In [80]: df
Out[80]:
    a   b   c
0   6  11  11
1  14   7   8
2  13   5  11
3  13   7  11
4  13   5   9
5   5  11   9
6   9   8   6
7   5  11  10
8   8  10  14
9   7  14  13

present only those rows where b > 10

In [81]: df[df.b > 10]
Out[81]:
   a   b   c
0  6  11  11
5  5  11   9
7  5  11  10
9  7  14  13

Minimums (for all columns) for the rows satisfying b > 10 condition

In [82]: df[df.b > 10].min()
Out[82]:
a     5
b    11
c     9
dtype: int32

Minimum (for the b column) for the rows satisfying b > 10 condition

In [84]: df.loc[df.b > 10, 'b'].min()
Out[84]: 11

UPDATE: starting from Pandas 0.20.1 the .ix indexer is deprecated, in favor of the more strict .iloc and .loc indexers.