Programs & Examples On #Preemptive

0

Calculating Waiting Time and Turnaround Time in (non-preemptive) FCFS queue

For non-preemptive system,

waitingTime = startTime - arrivalTime

turnaroundTime = burstTime + waitingTime = finishTime- arrivalTime

startTime = Time at which the process started executing

finishTime = Time at which the process finished executing

You can keep track of the current time elapsed in the system(timeElapsed). Assign all processors to a process in the beginning, and execute until the shortest process is done executing. Then assign this processor which is free to the next process in the queue. Do this until the queue is empty and all processes are done executing. Also, whenever a process starts executing, recored its startTime, when finishes, record its finishTime (both same as timeElapsed). That way you can calculate what you need.

"Active Directory Users and Computers" MMC snap-in for Windows 7?

There are new instructions as of the Windows 10 October 2018 update:

Just go to "Manage optional features" in Settings and click "Add a feature" to see the list of available RSAT tools. Select and install the specific RSAT tools you need. To see installation progress, click the Back button to view status on the "Manage optional features" page.

Source: https://www.microsoft.com/en-us/download/details.aspx?id=45520

How to fix error Base table or view not found: 1146 Table laravel relationship table?

You can add this in Post Model,

public function categories()
{
 return $this->belongsToMany('App\Category','category_post','post_id','category_id');                 
}

category_post indicate the table you want to use.
post_id indicate the column where you want to store the posts id.
category_id indicate the column where you want to store the categories id.

Calculate Pandas DataFrame Time Difference Between Two Columns in Hours and Minutes

Pandas timestamp differences returns a datetime.timedelta object. This can easily be converted into hours by using the *as_type* method, like so

import pandas
df = pandas.DataFrame(columns=['to','fr','ans'])
df.to = [pandas.Timestamp('2014-01-24 13:03:12.050000'), pandas.Timestamp('2014-01-27 11:57:18.240000'), pandas.Timestamp('2014-01-23 10:07:47.660000')]
df.fr = [pandas.Timestamp('2014-01-26 23:41:21.870000'), pandas.Timestamp('2014-01-27 15:38:22.540000'), pandas.Timestamp('2014-01-23 18:50:41.420000')]
(df.fr-df.to).astype('timedelta64[h]')

to yield,

0    58
1     3
2     8
dtype: float64

How to turn off gcc compiler optimization to enable buffer overflow

That's a good problem. In order to solve that problem you will also have to disable ASLR otherwise the address of g() will be unpredictable.

Disable ASLR:

sudo bash -c 'echo 0 > /proc/sys/kernel/randomize_va_space'

Disable canaries:

gcc overflow.c -o overflow -fno-stack-protector

After canaries and ASLR are disabled it should be a straight forward attack like the ones described in Smashing the Stack for Fun and Profit

Here is a list of security features used in ubuntu: https://wiki.ubuntu.com/Security/Features You don't have to worry about NX bits, the address of g() will always be in a executable region of memory because it is within the TEXT memory segment. NX bits only come into play if you are trying to execute shellcode on the stack or heap, which is not required for this assignment.

Now go and clobber that EIP!

How to write one new line in Bitbucket markdown?

Feb 3rd 2020:

  • Atlassian Bitbucket v5.8.3 local installation.
  • I wanted to add a new line around an horizontal line. --- did produce the line, but I could not get new lines to work with suggestions above.
  • note: I did not want to use the [space][space] suggestion, since my editor removes trailing spaces on save, and I like this feature on.

I ended up doing this:

TEXT...
<br><hr><br>
TEXT...

Resulting in:

TEXT...
<AN EMPTY LINE>
----------------- AN HORIZONTAL LINE ----------------
<AN EMPTY LINE>
TEXT...

X-Frame-Options on apache

This worked for me on all browsers:

  1. Created one page with all my javascript
  2. Created a 2nd page on the same server and embedded the first page using the object tag.
  3. On my third party site I used the Object tag to embed the 2nd page.
  4. Created a .htaccess file on the original server in the public_html folder and put Header unset X-Frame-Options in it.

Is there a decorator to simply cache function return values?

I implemented something like this, using pickle for persistance and using sha1 for short almost-certainly-unique IDs. Basically the cache hashed the code of the function and the hist of arguments to get a sha1 then looked for a file with that sha1 in the name. If it existed, it opened it and returned the result; if not, it calls the function and saves the result (optionally only saving if it took a certain amount of time to process).

That said, I'd swear I found an existing module that did this and find myself here trying to find that module... The closest I can find is this, which looks about right: http://chase-seibert.github.io/blog/2011/11/23/pythondjango-disk-based-caching-decorator.html

The only problem I see with that is it wouldn't work well for large inputs since it hashes str(arg), which isn't unique for giant arrays.

It would be nice if there were a unique_hash() protocol that had a class return a secure hash of its contents. I basically manually implemented that for the types I cared about.

How to scroll to top of a div using jQuery?

Here is what you can do using jquery:

$('#A_ID').click(function (e) { //#A_ID is an example. Use the id of your Anchor
    $('html, body').animate({
        scrollTop: $('#DIV_ID').offset().top - 20 //#DIV_ID is an example. Use the id of your destination on the page
    }, 'slow');
});

Adding a simple spacer to twitter bootstrap

In Bootstrap 4 you can use classes like mt-5, mb-5, my-5, mx-5 (y for both top and bottom, x for both left and right).

According to their site:

The classes are named using the format {property}{sides}-{size} for xs and {property}{sides}-{breakpoint}-{size} for sm, md, lg, and xl.

Link: https://getbootstrap.com/docs/4.0/utilities/spacing/

How to check a boolean condition in EL?

You can check this way too

<c:if test="${theBooleanVariable ne true}">It's false!</c:if>

How to select only 1 row from oracle sql?

select a.user from (select user from users order by user) a where rownum = 1

will perform the best, another option is:

select a.user 
from ( 
select user, 
row_number() over (order by user) user_rank, 
row_number() over (partition by dept order by user) user_dept_rank 
from users 
) a 
where a.user_rank = 1 or user_dept_rank = 2

in scenarios where you want different subsets, but I guess you could also use RANK() But, I also like row_number() over(...) since no grouping is required.

Getting the client IP address: REMOTE_ADDR, HTTP_X_FORWARDED_FOR, what else could be useful?

It depends on the nature of your site.

I happen to work on a bit of software where IP tracking is important, and within a field consumed by parter sites I'd guess some 20% - 40% of requests are either detectably spoofed IPs or headers blanked out, depending on the time of day and where they came from. For a site which gets organic traffic (i.e. not through partners) I'd expect a much higher ratio of good IPs.

As Kosi said, be careful what you're doing with this - IPs are in no way a reliable way to identify unique visitors.

HTML / CSS How to add image icon to input type="button"?

Simply add icon in button element here is the example

   <button class="social-signup facebook"> 
     <i class="fa fa-facebook-official"></i>  
      Sign up with Facebook</button>

Checking length of dictionary object

var c = {'a':'A', 'b':'B', 'c':'C'};
var count = 0;
for (var i in c) {
   if (c.hasOwnProperty(i)) count++;
}

alert(count);

How to implement a secure REST API with node.js

If you want to secure your application, then you should definitely start by using HTTPS instead of HTTP, this ensures a creating secure channel between you & the users that will prevent sniffing the data sent back & forth to the users & will help keep the data exchanged confidential.

You can use JWTs (JSON Web Tokens) to secure RESTful APIs, this has many benefits when compared to the server-side sessions, the benefits are mainly:

1- More scalable, as your API servers will not have to maintain sessions for each user (which can be a big burden when you have many sessions)

2- JWTs are self contained & have the claims which define the user role for example & what he can access & issued at date & expiry date (after which JWT won't be valid)

3- Easier to handle across load-balancers & if you have multiple API servers as you won't have to share session data nor configure server to route the session to same server, whenever a request with a JWT hit any server it can be authenticated & authorized

4- Less pressure on your DB as well as you won't have to constantly store & retrieve session id & data for each request

5- The JWTs can't be tampered with if you use a strong key to sign the JWT, so you can trust the claims in the JWT that is sent with the request without having to check the user session & whether he is authorized or not, you can just check the JWT & then you are all set to know who & what this user can do.

Many libraries provide easy ways to create & validate JWTs in most programming languages, for example: in node.js one of the most popular is jsonwebtoken

Since REST APIs generally aims to keep the server stateless, so JWTs are more compatible with that concept as each request is sent with Authorization token that is self contained (JWT) without the server having to keep track of user session compared to sessions which make the server stateful so that it remembers the user & his role, however, sessions are also widely used & have their pros, which you can search for if you want.

One important thing to note is that you have to securely deliver the JWT to the client using HTTPS & save it in a secure place (for example in local storage).

You can learn more about JWTs from this link

Init method in Spring Controller (annotation version)

There are several ways to intercept the initialization process in Spring. If you have to initialize all beans and autowire/inject them there are at least two ways that I know of that will ensure this. I have only testet the second one but I belive both work the same.

If you are using @Bean you can reference by initMethod, like this.

@Configuration
public class BeanConfiguration {

  @Bean(initMethod="init")
  public BeanA beanA() {
    return new BeanA();
  }
}

public class BeanA {

  // method to be initialized after context is ready
  public void init() {
  }

} 

If you are using @Component you can annotate with @EventListener like this.

@Component
public class BeanB {

  @EventListener
  public void onApplicationEvent(ContextRefreshedEvent event) {
  }
}

In my case I have a legacy system where I am now taking use of IoC/DI where Spring Boot is the choosen framework. The old system brings many circular dependencies to the table and I therefore must use setter-dependency a lot. That gave me some headaches since I could not trust @PostConstruct since autowiring/injection by setter was not yet done. The order is constructor, @PostConstruct then autowired setters. I solved it with @EventListener annotation which wil run last and at the "same" time for all beans. The example shows implementation of InitializingBean aswell.

I have two classes (@Component) with dependency to each other. The classes looks the same for the purpose of this example displaying only one of them.

@Component
public class BeanA implements InitializingBean {
  private BeanB beanB;

  public BeanA() {
    log.debug("Created...");
  }

  @PostConstruct
  private void postConstruct() {
    log.debug("@PostConstruct");
  }

  @Autowired
  public void setBeanB(BeanB beanB) {
    log.debug("@Autowired beanB");
    this.beanB = beanB;
  }

  @Override
  public void afterPropertiesSet() throws Exception {
    log.debug("afterPropertiesSet()");
  }

  @EventListener
  public void onApplicationEvent(ContextRefreshedEvent event) {
    log.debug("@EventListener");
  } 
}

This is the log output showing the order of the calls when the container starts.

2018-11-30 18:29:30.504 DEBUG 3624 --- [           main] com.example.demo.BeanA                   : Created...
2018-11-30 18:29:30.509 DEBUG 3624 --- [           main] com.example.demo.BeanB                   : Created...
2018-11-30 18:29:30.517 DEBUG 3624 --- [           main] com.example.demo.BeanB                   : @Autowired beanA
2018-11-30 18:29:30.518 DEBUG 3624 --- [           main] com.example.demo.BeanB                   : @PostConstruct
2018-11-30 18:29:30.518 DEBUG 3624 --- [           main] com.example.demo.BeanB                   : afterPropertiesSet()
2018-11-30 18:29:30.518 DEBUG 3624 --- [           main] com.example.demo.BeanA                   : @Autowired beanB
2018-11-30 18:29:30.518 DEBUG 3624 --- [           main] com.example.demo.BeanA                   : @PostConstruct
2018-11-30 18:29:30.518 DEBUG 3624 --- [           main] com.example.demo.BeanA                   : afterPropertiesSet()
2018-11-30 18:29:30.607 DEBUG 3624 --- [           main] com.example.demo.BeanA                   : @EventListener
2018-11-30 18:29:30.607 DEBUG 3624 --- [           main] com.example.demo.BeanB                   : @EventListener

As you can see @EventListener is run last after everything is ready and configured.

AttributeError: 'module' object has no attribute 'model'

I realized that by looking at the stack trace it was trying to load my own script in place of another module called the same way,i.e., my script was called random.py and when a module i used was trying to import the "random" package, it was loading my script causing a circular reference and so i renamed it and deleted a .pyc file it had created from the working folder and things worked just fine.

Can I install Python 3.x and 2.x on the same Windows computer?

Here is how to run Python 2 and 3 on the same machine

  1. install Python 2.x
  2. install Python 3.x
  3. Start Powershell
  4. Type Python -2 to launch Python 2.x
  5. Type Python -3 to launch Python 2.x

The Python Launcher for Windows was embedded into Python since Version 3.3, as promised in 2011 when the Stand alone first made its debut:

Python Launcher for Windows

MySQL SELECT last few days?

SELECT DATEDIFF(NOW(),pickup_date) AS noofday 
FROM cir_order 
WHERE DATEDIFF(NOW(),pickup_date)>2;

or

SELECT * 
FROM cir_order 
WHERE cir_order.`cir_date` >= DATE_ADD( CURDATE(), INTERVAL -10 DAY )

python encoding utf-8

Unfortunately, the string.encode() method is not always reliable. Check out this thread for more information: What is the fool proof way to convert some string (utf-8 or else) to a simple ASCII string in python

Purpose of __repr__ method?

__repr__ should return a printable representation of the object, most likely one of the ways possible to create this object. See official documentation here. __repr__ is more for developers while __str__ is for end users.

A simple example:

>>> class Point:
...   def __init__(self, x, y):
...     self.x, self.y = x, y
...   def __repr__(self):
...     return 'Point(x=%s, y=%s)' % (self.x, self.y)
>>> p = Point(1, 2)
>>> p
Point(x=1, y=2)

Do you get charged for a 'stopped' instance on EC2?

No.

You get charged for:

  1. Online time
  2. Storage space (assumably you store the image on S3 [EBS])
  3. Elastic IP addresses
  4. Bandwidth

So... if you stop the EC2 instance you will only have to pay for the storage of the image on S3 (assuming you store an image ofcourse) and any IP addresses you've reserved.

Get last 30 day records from today date in SQL Server

I dont know why all these complicated answers are on here but this is what I would do

where pdate >= CURRENT_TIMESTAMP -30

OR WHERE CAST(PDATE AS DATE) >= GETDATE() -30

Commit empty folder structure (with git)

In Git, you cannot commit empty folders, because Git does not actually save folders, only files. You'll have to create some placeholder file inside those directories if you actually want them to be "empty" (i.e. you have no committable content).

How to convert a list into data table

Just add this function and call it, it will convert List to DataTable.

public static DataTable ToDataTable<T>(List<T> items)
{
        DataTable dataTable = new DataTable(typeof(T).Name);

        //Get all the properties
        PropertyInfo[] Props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
        foreach (PropertyInfo prop in Props)
        {
            //Defining type of data column gives proper data table 
            var type = (prop.PropertyType.IsGenericType && prop.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>) ? Nullable.GetUnderlyingType(prop.PropertyType) : prop.PropertyType);
            //Setting column names as Property names
            dataTable.Columns.Add(prop.Name, type);
        }
        foreach (T item in items)
        {
           var values = new object[Props.Length];
           for (int i = 0; i < Props.Length; i++)
           {
                //inserting property values to datatable rows
                values[i] = Props[i].GetValue(item, null);
           }
           dataTable.Rows.Add(values);
      }
      //put a breakpoint here and check datatable
      return dataTable;
}

SecurityError: The operation is insecure - window.history.pushState()

I had the same problem when called another javascript file from a file without putting javascript "physical" address. I solved it by calling it same way from the html, example: "JS / archivo.js" instead of "archivo.js"

c++ bool question

Yes that is correct. "Boolean variables only have two possible values: true (1) and false (0)." cpp tutorial on boolean values

Copying files to a container with Docker Compose

Given

    volumes:
      - /dir/on/host:/var/www/html

if /dir/on/host doesn't exist, it is created on the host and the empty content is mounted in the container at /var/www/html. Whatever content you had before in /var/www/html inside the container is inaccessible, until you unmount the volume; the new mount is hiding the old content.

How to use [DllImport("")] in C#?

You can't declare an extern local method inside of a method, or any other method with an attribute. Move your DLL import into the class:

using System.Runtime.InteropServices;


public class WindowHandling
{
    [DllImport("User32.dll")]
    public static extern int SetForegroundWindow(IntPtr point);

    public void ActivateTargetApplication(string processName, List<string> barcodesList)
    {
        Process p = Process.Start("notepad++.exe");
        p.WaitForInputIdle();
        IntPtr h = p.MainWindowHandle;
        SetForegroundWindow(h);
        SendKeys.SendWait("k");
        IntPtr processFoundWindow = p.MainWindowHandle;
    }
}

Laravel PDOException SQLSTATE[HY000] [1049] Unknown database 'forge'

You need to modify the name of the DB in the file .env (and if need in .env.example) I solved my problem with this little correction.

Array to String PHP?

$data = array("asdcasdc","35353","asdca353sdc","sadcasdc","sadcasdc","asdcsdcsad");

$string_array = json_encode($data);

now you can insert this $string_array value into Database

WCF ServiceHost access rights

Open a command prompt as the administrator and you write below command to add your URL:

netsh http add urlacl url=http://+:8000/YourServiceLibrary/YourService user=Everyone

Jenkins pipeline how to change to another folder

Use WORKSPACE environment variable to change workspace directory.

If doing using Jenkinsfile, use following code :

dir("${env.WORKSPACE}/aQA"){
    sh "pwd"
}

How do I create an Android Spinner as a popup?

In xml there is option

android:spinnerMode="dialog"

use this for Dialog mode

how to check for special characters php

preg_match('/'.preg_quote('^\'£$%^&*()}{@#~?><,@|-=-_+-¬', '/').'/', $string);

Generate sha256 with OpenSSL and C++

I think that you only have to replace SHA1 function with SHA256 function with tatk code from link in Your post

How do I clear my local working directory in Git?

To reset a specific file to the last-committed state (to discard uncommitted changes in a specific file):

git checkout thefiletoreset.txt

This is mentioned in the git status output:

(use "git checkout -- <file>..." to discard changes in working directory)

To reset the entire repository to the last committed state:

git reset --hard

To remove untracked files, I usually just delete all files in the working copy (but not the .git/ folder!), then do git reset --hard which leaves it with only committed files.

A better way is to use git clean (warning: using the -x flag as below will cause Git to delete ignored files):

git clean -d -x -f

will remove untracked files, including directories (-d) and files ignored by git (-x). Replace the -f argument with -n to perform a dry-run or -i for interactive mode, and it will tell you what will be removed.

Relevant links:

Getting ORA-01031: insufficient privileges while querying a table instead of ORA-00942: table or view does not exist

ORA-01031: insufficient privileges Solution: Go to Your System User. then Write This Code:

SQL> grant dba to UserName; //Put This username which user show this error message.

Grant succeeded.

PHP str_replace replace spaces with underscores

For one matched character replace, use str_replace:

$string = str_replace(' ', '_', $string);

For all matched character replace, use preg_replace:

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

Custom fonts and XML layouts (Android)

Also can be defined in the xml without creating custom classes

style.xml

<style name="ionicons" parent="android:TextAppearance">
    <!-- Custom Attr-->
    <item name="fontPath">fonts/ionicons.ttf</item>
</style>

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:app="http://schemas.android.com/apk/res-auto"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical" >
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="@style/ionicons"
        android:text="?"/>
</LinearLayout>

A quick note, because I just always forgot where to put the fonts, its that the font must be inside assets and this folder resides in the same level that res and src, in my case its assets/fonts/ionicons.ttf

Updated Added root layout because this method needs xmlns:app="http://schemas.android.com/apk/res-auto" to work

Update 2 Forgot about a library that I've installed before called Calligraphy

Timestamp with a millisecond precision: How to save them in MySQL

You need to be at MySQL version 5.6.4 or later to declare columns with fractional-second time datatypes. Not sure you have the right version? Try SELECT NOW(3). If you get an error, you don't have the right version.

For example, DATETIME(3) will give you millisecond resolution in your timestamps, and TIMESTAMP(6) will give you microsecond resolution on a *nix-style timestamp.

Read this: https://dev.mysql.com/doc/refman/8.0/en/fractional-seconds.html

NOW(3) will give you the present time from your MySQL server's operating system with millisecond precision.

If you have a number of milliseconds since the Unix epoch, try this to get a DATETIME(3) value

FROM_UNIXTIME(ms * 0.001)

Javascript timestamps, for example, are represented in milliseconds since the Unix epoch.

(Notice that MySQL internal fractional arithmetic, like * 0.001, is always handled as IEEE754 double precision floating point, so it's unlikely you'll lose precision before the Sun becomes a white dwarf star.)

If you're using an older version of MySQL and you need subsecond time precision, your best path is to upgrade. Anything else will force you into doing messy workarounds.

If, for some reason you can't upgrade, you could consider using BIGINT or DOUBLE columns to store Javascript timestamps as if they were numbers. FROM_UNIXTIME(col * 0.001) will still work OK. If you need the current time to store in such a column, you could use UNIX_TIMESTAMP() * 1000

Test if string begins with a string?

Judging by the declaration and description of the startsWith Java function, the "most straight forward way" to implement it in VBA would either be with Left:

Public Function startsWith(str As String, prefix As String) As Boolean
    startsWith = Left(str, Len(prefix)) = prefix
End Function

Or, if you want to have the offset parameter available, with Mid:

Public Function startsWith(str As String, prefix As String, Optional toffset As Integer = 0) As Boolean
    startsWith = Mid(str, toffset + 1, Len(prefix)) = prefix
End Function

How to prevent page scrolling when scrolling a DIV element?

I needed to add this event to multiple elements that might have a scrollbar. For the cases where no scrollbar was present, the main scrollbar didn't work as it should. So i made a small change to @Šime code as follows:

$( '.scrollable' ).on( 'mousewheel DOMMouseScroll', function ( e ) {
    if($(this).prop('scrollHeight') > $(this).height())
    {
        var e0 = e.originalEvent, delta = e0.wheelDelta || -e0.detail;

        this.scrollTop += ( delta < 0 ? 1 : -1 ) * 30;
        e.preventDefault();
    }       
});

Now, only elements with a scrollbar will prevent the main scroll from begin stopped.

How may I sort a list alphabetically using jQuery?

To make this work work with all browsers including Chrome you need to make the callback function of sort() return -1,0 or 1.

see http://inderpreetsingh.com/2010/12/01/chromes-javascript-sort-array-function-is-different-yet-proper/

function sortUL(selector) {
    $(selector).children("li").sort(function(a, b) {
        var upA = $(a).text().toUpperCase();
        var upB = $(b).text().toUpperCase();
        return (upA < upB) ? -1 : (upA > upB) ? 1 : 0;
    }).appendTo(selector);
}
sortUL("ul.mylist");

Broken references in Virtualenvs

virtualenvwrapper instructions

As indicated in the accepted answer, the root cause is likely a homebrew update that means your virtualenv symlinks are pointing at broken python paths - see details here.

For each virtual env, you need to reassign the symlinks to point at the correct python path (in brew cellar). Here is how to do it with virtualenvwrapper. Here I am updating a virtual env called "my-example-env".

cd ~/PYTHON_ENVS
find ./my-example-env -type l -delete
mkvirtualenv my-example-env

All done.

IF EXISTS condition not working with PLSQL

Unfortunately PL/SQL doesn't have IF EXISTS operator like SQL Server. But you can do something like this:

begin
  for x in ( select count(*) cnt
               from dual 
              where exists (
                select 1 from courseoffering co
                  join co_enrolment ce on ce.co_id = co.co_id
                 where ce.s_regno = 403 
                   and ce.coe_completionstatus = 'C' 
                   and co.c_id = 803 ) )
  loop
        if ( x.cnt = 1 ) 
        then
           dbms_output.put_line('exists');
        else 
           dbms_output.put_line('does not exist');
        end if;
  end loop;
end;
/

JSON.Parse,'Uncaught SyntaxError: Unexpected token o

var jsonStringNoQuotes = [{"Id":"10","Name":"Matt"},{"Id":"1","Name":"Rock"}];

it will create json object. no need to parse.

jsonStringQuotes = "'" + jsonStringNoQuotes + "'";

will return '[object]'

thats why it(below) is causing error

var myData = JSON.parse(jsonStringQuotes);

Foreign key referencing a 2 columns primary key in SQL Server

The key is "the order of the column should be the same"

Example:

create Table A (
    A_ID char(3) primary key,
    A_name char(10) primary key,
    A_desc desc char(50)
)

create Table B (
    B_ID char(3) primary key,
    B_A_ID char(3),
    B_A_Name char(10),
    constraint [Fk_B_01] foreign key (B_A_ID,B_A_Name) references A(A_ID,A_Name)
)

the column order on table A should be --> A_ID then A_Name; defining the foreign key should follow the same order as well.

Why can't I see the "Report Data" window when creating reports?

Hi I faced the same issue in VS2008, I tried based on the post 8 (Thanks to the "Tricky part" section in that)

The (Ctrl+Alt+D) combo did not work there in VS2008, but after opening the Report file(rdlc) I browsed on the View menu and found out that View->Toolbars->Data Design is the solution for that.

Upon opening that we get around 4 icons of which the "Show Data Sources" section brings the "Website Data Sources" section which fetches all Entities, Typed DataSets etc.

The keybord shortcut is (Shift+Alt+D).

The twisty part here is the "Data Sources" section available with the Server Explorer toolbar doesnt bring up any stuff but the "Website Data Sources" brings all the needed., can somebody explain that to me.

Clone private git repo with dockerfile

You often do not want to perform a git clone of a private repo from within the docker build. Doing the clone there involves placing the private ssh credentials inside the image where they can be later extracted by anyone with access to your image.

Instead, the common practice is to clone the git repo from outside of docker in your CI tool of choice, and simply COPY the files into the image. This has a second benefit: docker caching. Docker caching looks at the command being run, environment variables it includes, input files, etc, and if they are identical to a previous build from the same parent step, it reuses that previous cache. With a git clone command, the command itself is identical, so docker will reuse the cache even if the external git repo is changed. However, a COPY command will look at the files in the build context and can see if they are identical or have been updated, and use the cache only when it's appropriate.


If you are going to add credentials into your build, consider doing so with a multi-stage build, and only placing those credentials in an early stage that is never tagged and pushed outside of your build host. The result looks like:

FROM ubuntu as clone

# Update aptitude with new repo
RUN apt-get update \
 && apt-get install -y git
# Make ssh dir
# Create known_hosts
# Add bitbuckets key
RUN mkdir /root/.ssh/ \
 && touch /root/.ssh/known_hosts \
 && ssh-keyscan bitbucket.org >> /root/.ssh/known_hosts

# Copy over private key, and set permissions
# Warning! Anyone who gets their hands on this image will be able
# to retrieve this private key file from the corresponding image layer
COPY id_rsa /root/.ssh/id_rsa

# Clone the conf files into the docker container
RUN git clone [email protected]:User/repo.git

FROM ubuntu as release
LABEL maintainer="Luke Crooks <[email protected]>"

COPY --from=clone /repo /repo
...

More recently, BuildKit has been testing some experimental features that allow you to pass an ssh key in as a mount that never gets written to the image:

# syntax=docker/dockerfile:experimental
FROM ubuntu as clone
LABEL maintainer="Luke Crooks <[email protected]>"

# Update aptitude with new repo
RUN apt-get update \
 && apt-get install -y git

# Make ssh dir
# Create known_hosts
# Add bitbuckets key
RUN mkdir /root/.ssh/ \
 && touch /root/.ssh/known_hosts \
 && ssh-keyscan bitbucket.org >> /root/.ssh/known_hosts

# Clone the conf files into the docker container
RUN --mount=type=secret,id=ssh_id,target=/root/.ssh/id_rsa \
    git clone [email protected]:User/repo.git

And you can build that with:

$ DOCKER_BUILDKIT=1 docker build -t your_image_name \
  --secret id=ssh_id,src=$(pwd)/id_rsa .

Note that this still requires your ssh key to not be password protected, but you can at least run the build in a single stage, removing a COPY command, and avoiding the ssh credential from ever being part of an image.


BuildKit also added a feature just for ssh which allows you to still have your password protected ssh keys, the result looks like:

# syntax=docker/dockerfile:experimental
FROM ubuntu as clone
LABEL maintainer="Luke Crooks <[email protected]>"

# Update aptitude with new repo
RUN apt-get update \
 && apt-get install -y git

# Make ssh dir
# Create known_hosts
# Add bitbuckets key
RUN mkdir /root/.ssh/ \
 && touch /root/.ssh/known_hosts \
 && ssh-keyscan bitbucket.org >> /root/.ssh/known_hosts

# Clone the conf files into the docker container
RUN --mount=type=ssh \
    git clone [email protected]:User/repo.git

And you can build that with:

$ eval $(ssh-agent)
$ ssh-add ~/.ssh/id_rsa
(Input your passphrase here)
$ DOCKER_BUILDKIT=1 docker build -t your_image_name \
  --ssh default=$SSH_AUTH_SOCK .

Again, this is injected into the build without ever being written to an image layer, removing the risk that the credential could accidentally leak out.


To force docker to run the git clone even when the lines before have been cached, you can inject a build ARG that changes with each build to break the cache. That looks like:

# inject a datestamp arg which is treated as an environment variable and
# will break the cache for the next RUN command
ARG DATE_STAMP
# Clone the conf files into the docker container
RUN git clone [email protected]:User/repo.git

Then you inject that changing arg in the docker build command:

date_stamp=$(date +%Y%m%d-%H%M%S)
docker build --build-arg DATE_STAMP=$date_stamp .

Why Java Calendar set(int year, int month, int date) not returning correct date?

Selected date at the example is interesting. Example code block is:

Calendar c1 = GregorianCalendar.getInstance();
c1.set(2000, 1, 30);  //January 30th 2000
Date sDate = c1.getTime();

System.out.println(sDate);

and output Wed Mar 01 19:32:21 JST 2000.

When I first read the example i think that output is wrong but it is true:)

  • Calendar.Month is starting from 0 so 1 means February.
  • February last day is 28 so output should be 2 March.
  • But selected year is important, it is 2000 which means February 29 so result should be 1 March.

How to detect online/offline event cross-browser?

Today there's an open source JavaScript library that does this job: it's called Offline.js.

Automatically display online/offline indication to your users.

https://github.com/HubSpot/offline

Be sure to check the full README. It contains events that you can hook into.

Here's a test page. It's beautiful/has a nice feedback UI by the way! :)

Offline.js Simulate UI is an Offline.js plug-in that allows you to test how your pages respond to different connectivity states without having to use brute-force methods to disable your actual connectivity.

Oracle - How to create a readonly user

A user in an Oracle database only has the privileges you grant. So you can create a read-only user by simply not granting any other privileges.

When you create a user

CREATE USER ro_user
 IDENTIFIED BY ro_user
 DEFAULT TABLESPACE users
 TEMPORARY TABLESPACE temp;

the user doesn't even have permission to log in to the database. You can grant that

GRANT CREATE SESSION to ro_user

and then you can go about granting whatever read privileges you want. For example, if you want RO_USER to be able to query SCHEMA_NAME.TABLE_NAME, you would do something like

GRANT SELECT ON schema_name.table_name TO ro_user

Generally, you're better off creating a role, however, and granting the object privileges to the role so that you can then grant the role to different users. Something like

Create the role

CREATE ROLE ro_role;

Grant the role SELECT access on every table in a particular schema

BEGIN
  FOR x IN (SELECT * FROM dba_tables WHERE owner='SCHEMA_NAME')
  LOOP
    EXECUTE IMMEDIATE 'GRANT SELECT ON schema_name.' || x.table_name || 
                                  ' TO ro_role';
  END LOOP;
END;

And then grant the role to the user

GRANT ro_role TO ro_user;

How to create a release signed apk file using Gradle?

If you have the keystore file already, it can be as simple as adding a few parameters to your build command:

./gradlew assembleRelease \
 -Pandroid.injected.signing.store.file=$KEYFILE \
 -Pandroid.injected.signing.store.password=$STORE_PASSWORD \
 -Pandroid.injected.signing.key.alias=$KEY_ALIAS \
 -Pandroid.injected.signing.key.password=$KEY_PASSWORD

No permanent changes to your Android project necessary.

Source: http://www.tinmith.net/wayne/blog/2014/08/gradle-sign-command-line.htm

CSS selectors ul li a {...} vs ul > li > a {...}

Here > a to specifiy the color for root of li.active.menu-item

#primary-menu > li.active.menu-item > a

_x000D_
_x000D_
#primary-menu>li.active.menu-item>a {_x000D_
  color: #c19b66;_x000D_
}
_x000D_
<ul id="primary-menu">_x000D_
  <li class="active menu-item"><a>Coffee</a>_x000D_
    <ul id="sub-menu">_x000D_
      <li class="active menu-item"><a>aaa</a></li>_x000D_
      <li class="menu-item"><a>bbb</a></li>_x000D_
      <li class="menu-item"><a>ccc</a></li>_x000D_
    </ul>_x000D_
  </li>_x000D_
_x000D_
  <li class="menu-item"><a>Tea</a></li>_x000D_
  <li class="menu-item"><a>Coca Cola</a></li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

How to see tomcat is running or not

open http://localhost:8080/ in browser, if you get tomcat home page. it means tomcat is running

Unable to create a constant value of type Only primitive types or enumeration types are supported in this context

I had this issue and what I did and solved the problem was that I used AsEnumerable() just before my Join clause. here is my query:

List<AccountViewModel> selectedAccounts;

 using (ctx = SmallContext.GetInstance()) {
                var data = ctx.Transactions.
                    Include(x => x.Source).
                    Include(x => x.Relation).
                    AsEnumerable().
                    Join(selectedAccounts, x => x.Source.Id, y => y.Id, (x, y) => x).
                    GroupBy(x => new { Id = x.Relation.Id, Name = x.Relation.Name }).
                    ToList();
            }

I was wondering why this issue happens, and now I think It is because after you make a query via LINQ, the result will be in memory and not loaded into objects, I don't know what that state is but they are in in some transitional state I think. Then when you use AsEnumerable() or ToList(), etc, you are placing them into physical memory objects and the issue is resolving.

javascript popup alert on link click

In order to do this you need to attach the handler to a specific anchor on the page. For operations like this it's much easier to use a standard framework like jQuery. For example if I had the following HTML

HTML:

<a id="theLink">Click Me</a>

I could use the following jQuery to hookup an event to that specific link.

// Use ready to ensure document is loaded before running javascript
$(document).ready(function() {

  // The '#theLink' portion is a selector which matches a DOM element
  // with the id 'theLink' and .click registers a call back for the 
  // element being clicked on 
  $('#theLink').click(function (event) {

    // This stops the link from actually being followed which is the 
    // default action 
    event.preventDefault();

    var answer confirm("Please click OK to continue");
    if (!answer) {
      window.location="http://www.continue.com"
    }
  });

});

Is there a concurrent List in Java's JDK?

You have these options:

  • Collections.synchronizedList(): you can wrap any List implementation (ArrayList, LinkedList or a 3rd-party list). Access to every method (reading and writing) will be protected using synchronized. When using iterator() or enhanced for loop, you must manually synchronize the whole iteration. While iterating, other threads are fully blocked even from reading. You can also synchronize separately for each hasNext and next calls, but then ConcurrentModificationException is possible.

  • CopyOnWriteArrayList: it's expensive to modify, but wait-free to read. Iterators never throw ConcurrentModificationException, they return a snapshot of the list at the moment of iterator creation even if the list is modified by another thread while iterating. Useful for infrequently updated lists. Bulk operations like addAll are preferred for updates - the internal array is copied less many times.

  • Vector: very much like synchronizedList(new ArrayList<>()), but iteration is synchronized too. However, iterators can throw ConcurrentModificationException if the vector is modified by another thread while iterating.

Other options:

  • Collections.unmodifiableList(): lock-free, thread-safe, but non-modifiable
  • List.of & List.copyOf: Another non-modifiable list in Java 9 and later.
  • Queue or Deque might be an alternative if you only add/remove at the ends of the list and iterate the list. There's no access by index and no adding/removing at arbitrary places. They have multiple concurrent implementations with better performance and better concurrent access, but it's beyond the scope of this question. You can also have a look at JCTools, they contain more performant queue implementations specialized for single consumer or single producer.

Rails: How to list database tables/objects using the Rails console?

You are probably seeking:

ActiveRecord::Base.connection.tables

and

ActiveRecord::Base.connection.columns('projects').map(&:name)

You should probably wrap them in shorter syntax inside your .irbrc.

How to create a GUID / UUID

You could use the npm package guid, a guid generator and validator.

https://www.npmjs.com/package/guid

Example:

Guid.raw();
// -> '6fdf6ffc-ed77-94fa-407e-a7b86ed9e59d'

UPDATE: This package has been deprecated. Use uuid instead.

https://www.npmjs.com/package/uuid

Example:

const uuidv4 = require('uuid/v4');
uuidv4(); // ? '10ba038e-48da-487b-96e8-8d3b99b6d18a'

search in java ArrayList

In Java 8:

Customer findCustomerByid(int id) {
    return this.customers.stream()
        .filter(customer -> customer.getId().equals(id))
        .findFirst().get();
}

It might also be better to change the return type to Optional<Customer>.

How to place a div on the right side with absolute position

You can use "translateX"

<div class="box">
<div class="absolute-right"></div>
</div>

<style type="text/css">
.box{
    text-align: right;
}
.absolute-right{
    display: inline-block;
    position: absolute;
}

/*The magic:*/
.absolute-right{
-moz-transform: translateX(-100%);
-ms-transform: translateX(-100%);
-webkit-transform: translateX(-100%);
-o-transform: translateX(-100%);
transform: translateX(-100%);
}
</style>

Timeout for python requests.get entire response

timeout = int(seconds)

Since requests >= 2.4.0, you can use the timeout argument, i.e:

requests.get('https://duckduckgo.com/', timeout=10)

Note:

timeout is not a time limit on the entire response download; rather, an exception is raised if the server has not issued a response for timeout seconds ( more precisely, if no bytes have been received on the underlying socket for timeout seconds). If no timeout is specified explicitly, requests do not time out.

Objective-C implicit conversion loses integer precision 'NSUInteger' (aka 'unsigned long') to 'int' warning

Change key in Project > Build Setting "typecheck calls to printf/scanf : NO"

Explanation : [How it works]

Check calls to printf and scanf, etc., to make sure that the arguments supplied have types appropriate to the format string specified, and that the conversions specified in the format string make sense.

Hope it work

Other warning

objective c implicit conversion loses integer precision 'NSUInteger' (aka 'unsigned long') to 'int

Change key "implicit conversion to 32Bits Type > Debug > *64 architecture : No"

[caution: It may void other warning of 64 Bits architecture conversion].

Bootstrap: Collapse other sections when one is expanded

The Method Works Properly For me:

var lanopt = $(".language-option");

lanopt.on("show.bs.collapse",".collapse", function(){
   lanopt.find(".collapse.in").collapse("hide");
});

golang why don't we have a set datastructure

One reason is that it is easy to create a set from map:

s := map[int]bool{5: true, 2: true}
_, ok := s[6] // check for existence
s[8] = true // add element 
delete(s, 2) // remove element

Union

s_union := map[int]bool{}
for k, _ := range s1{
    s_union[k] = true
}
for k, _ := range s2{
    s_union[k] = true
}

Intersection

s_intersection := map[int]bool{}
for k,_ := range s1 { 
  if s2[k] {
    s_intersection[k] = true
  }
}

It is not really that hard to implement all other set operations.

How to install Anaconda on RaspBerry Pi 3 Model B

Installing Miniconda on Raspberry Pi and adding Python 3.5 / 3.6

Skip the first section if you have already installed Miniconda successfully.

Installation of Miniconda on Raspberry Pi

wget http://repo.continuum.io/miniconda/Miniconda3-latest-Linux-armv7l.sh
sudo md5sum Miniconda3-latest-Linux-armv7l.sh
sudo /bin/bash Miniconda3-latest-Linux-armv7l.sh

Accept the license agreement with yes

When asked, change the install location: /home/pi/miniconda3

Do you wish the installer to prepend the Miniconda3 install location to PATH in your /root/.bashrc ? yes

Now add the install path to the PATH variable:

sudo nano /home/pi/.bashrc

Go to the end of the file .bashrc and add the following line:

export PATH="/home/pi/miniconda3/bin:$PATH"

Save the file and exit.

To test if the installation was successful, open a new terminal and enter

conda

If you see a list with commands you are ready to go.

But how can you use Python versions greater than 3.4 ?


Adding Python 3.5 / 3.6 to Miniconda on Raspberry Pi

After the installation of Miniconda I could not yet install Python versions higher than Python 3.4, but i needed Python 3.5. Here is the solution which worked for me on my Raspberry Pi 4:

First i added the Berryconda package manager by jjhelmus (kind of an up-to-date version of the armv7l version of Miniconda):

conda config --add channels rpi

Only now I was able to install Python 3.5 or 3.6 without the need for compiling it myself:

conda install python=3.5
conda install python=3.6

Afterwards I was able to create environments with the added Python version, e.g. with Python 3.5:

conda create --name py35 python=3.5

The new environment "py35" can now be activated:

source activate py35

Using Python 3.7 on Raspberry Pi

Currently Jonathan Helmus, who is the developer of berryconda, is working on adding Python 3.7 support, if you want to see if there is an update or if you want to support him, have a look at this pull request. (update 20200623) berryconda is now inactive, This project is no longer active, no recipe will be updated and no packages will be added to the rpi channel. If you need to run Python 3.7 on your Pi right now, you can do so without Miniconda. Check if you are running the latest version of Raspbian OS called Buster. Buster ships with Python 3.7 preinstalled (source), so simply run your program with the following command:

Python3.7 app-that-needs-python37.py

I hope this solution will work for you too!

JAX-WS client : what's the correct path to access the local WSDL?

For those of you using Spring, you can simply reference any classpath-resource using the classpath-protocol. So in case of the wsdlLocation, this becomes:

<wsdlLocation>classpath:META-INF/webservice.wsdl</wsdlLocation>

Note that is not standard Java behavior. See also: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/resources.html

Get latitude and longitude based on location name with Google Autocomplete API

You can use the Google Geocoder service in the Google Maps API to convert from your location name to a latitude and longitude. So you need some code like:

var geocoder = new google.maps.Geocoder();
var address = document.getElementById("address").value;
geocoder.geocode( { 'address': address}, function(results, status) {
  if (status == google.maps.GeocoderStatus.OK)
  {
      // do something with the geocoded result
      //
      // results[0].geometry.location.latitude
      // results[0].geometry.location.longitude
  }
});

Update

Are you including the v3 javascript API?

<script type="text/javascript"
     src="http://maps.google.com/maps/api/js?sensor=set_to_true_or_false">
</script> 

How to convert a pymongo.cursor.Cursor into a dict?

Map function is fast way to convert big collection

from time import time


cursor = db.collection.find()

def f(x):
    return x['name']

t1 = time()
blackset = set(map(f, cursor))
print(time() - t1)

How to remove line breaks (no characters!) from the string?

Ben's solution is acceptable, but str_replace() is by far faster than preg_replace()

$buffer = str_replace(array("\r", "\n"), '', $buffer);

Using less CPU power, reduces the world carbon dioxide emissions.

What is the path for the startup folder in windows 2008 server

SHGetKnownFolderPath:

Retrieves the full path of a known folder identified by the folder's KNOWNFOLDERID.

And, FOLDERID_CommonStartup:

Default Path %ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\StartUp

There are also managed equivalents, but you haven't told us what you're programming in.

What is the purpose of using -pedantic in GCC/G++ compiler?

Pedantic makes it so that the gcc compiler rejects all GNU C extensions not just the ones that make it ANSI compatible.

Replace a value if null or undefined in JavaScript

Destructuring solution

Question content may have changed, so I'll try to answer thoroughly.

Destructuring allows you to pull values out of anything with properties. You can also define default values when null/undefined and name aliases.

const options = {
    filters : {
        firstName : "abc"
    } 
}

const {filters: {firstName = "John", lastName = "Smith"}} = options

// firstName = "abc"
// lastName = "Smith"

NOTE: Capitalization matters

If working with an array, here is how you do it.

In this case, name is extracted from each object in the array, and given its own alias. Since the object might not exist = {} was also added.

const options = {
    filters: [{
        name: "abc",
        value: "lots"
    }]
}

const {filters:[{name : filter1 = "John"} = {}, {name : filter2 = "Smith"} = {}]} = options

// filter1 = "abc"
// filter2 = "Smith"

More Detailed Tutorial

Browser Support 92% July 2020

EXCEL VBA Check if entry is empty or not 'space'

Here is the code to check whether value is present or not.

If Trim(textbox1.text) <> "" Then
     'Your code goes here
Else
     'Nothing
End If

I think this will help.

How to hide soft keyboard on android after clicking outside EditText?

Instead of iterating through all the views or overriding dispatchTouchEvent.

Why Not just override the onUserInteraction() of the Activity this will make sure keyboard dismisses whenever the user taps outside of EditText.

Will work even when EditText is inside the scrollView.

@Override
public void onUserInteraction() {
    if (getCurrentFocus() != null) {
        InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
    }
}

Formula to determine brightness of RGB color

I think what you are looking for is the RGB -> Luma conversion formula.

Photometric/digital ITU BT.709:

Y = 0.2126 R + 0.7152 G + 0.0722 B

Digital ITU BT.601 (gives more weight to the R and B components):

Y = 0.299 R + 0.587 G + 0.114 B

If you are willing to trade accuracy for perfomance, there are two approximation formulas for this one:

Y = 0.33 R + 0.5 G + 0.16 B

Y = 0.375 R + 0.5 G + 0.125 B

These can be calculated quickly as

Y = (R+R+B+G+G+G)/6

Y = (R+R+R+B+G+G+G+G)>>3

Java equivalent of unsigned long long?

Depending on the operations you intend to perform, the outcome is much the same, signed or unsigned. However, unless you are using trivial operations you will end up using BigInteger.

Access multiple viewchildren using @viewchild

Use @ViewChildren from @angular/core to get a reference to the components

template

<div *ngFor="let v of views">
    <customcomponent #cmp></customcomponent>
</div>

component

import { ViewChildren, QueryList } from '@angular/core';

/** Get handle on cmp tags in the template */
@ViewChildren('cmp') components:QueryList<CustomComponent>;

ngAfterViewInit(){
    // print array of CustomComponent objects
    console.log(this.components.toArray());
}

l?i?v?e? ?d?e?m?o?

How can I select item with class within a DIV?

Try this

$("#mydiv div.myclass")

In Unix, how do you remove everything in the current directory and below it?

I believe this answer is better:

https://unix.stackexchange.com/questions/12593/how-to-remove-all-the-files-in-a-directory

If your top-level directory is called images, then run rm -r images/*. This uses the shell glob operator * to run rm -r on every file or directory within images.

basically you go up one level, and then say delete everything inside X directory. This way you are still specifying what folder should have its content deleted, which is safer than just saying 'delete everything here", while preserving the original folder, (which sometimes you want to because you aren't allowed or just don't want to modify the folder's existing permissions)

Parsing Json rest api response in C#

1> Add this namspace. using Newtonsoft.Json.Linq;

2> use this source code.

JObject joResponse = JObject.Parse(response);                   
JObject ojObject = (JObject)joResponse["response"];
JArray array= (JArray)ojObject ["chats"];
int id = Convert.ToInt32(array[0].toString());

Using the "animated circle" in an ImageView while loading stuff

You can do this by using the following xml

<RelativeLayout
    style="@style/GenericProgressBackground"
    android:id="@+id/loadingPanel"
    >
    <ProgressBar
        style="@style/GenericProgressIndicator"/>
</RelativeLayout>

With this style

<style name="GenericProgressBackground" parent="android:Theme">
    <item name="android:layout_width">fill_parent</item>    
    <item name="android:layout_height">fill_parent</item>
    <item name="android:background">#DD111111</item>    
    <item name="android:gravity">center</item>  
</style>
<style name="GenericProgressIndicator" parent="@android:style/Widget.ProgressBar.Small">
    <item name="android:layout_width">wrap_content</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:indeterminate">true</item> 
</style>

To use this, you must hide your UI elements by setting the visibility value to GONE and whenever the data is loaded, call setVisibility(View.VISIBLE) on all your views to restore them. Don't forget to call findViewById(R.id.loadingPanel).setVisiblity(View.GONE) to hide the loading animation.

If you dont have a loading event/function but just want the loading panel to disappear after x seconds use a Handle to trigger the hiding/showing.

Does Python's time.time() return the local or UTC timestamp?

Based on the answer from #squiguy, to get a true timestamp I would type cast it from float.

>>> import time
>>> ts = int(time.time())
>>> print(ts)
1389177318

At least that's the concept.

Unity 2d jumping script

Usually for jumping people use Rigidbody2D.AddForce with Forcemode.Impulse. It may seem like your object is pushed once in Y axis and it will fall down automatically due to gravity.

Example:

rigidbody2D.AddForce(new Vector2(0, 10), ForceMode2D.Impulse);

How to Ignore "Duplicate Key" error in T-SQL (SQL Server)

Keys must be unique. Don't do that. Redesign as needed.

(if you are trying to insert, then delete, and the insert fails... just do the delete first. Rollback on error in either statement).

How to parse XML and count instances of a particular node attribute?

I suggest xmltodict for simplicity.

It parses your XML to an OrderedDict;

>>> e = '<foo>
             <bar>
                 <type foobar="1"/>
                 <type foobar="2"/>
             </bar>
        </foo> '

>>> import xmltodict
>>> result = xmltodict.parse(e)
>>> result

OrderedDict([(u'foo', OrderedDict([(u'bar', OrderedDict([(u'type', [OrderedDict([(u'@foobar', u'1')]), OrderedDict([(u'@foobar', u'2')])])]))]))])

>>> result['foo']

OrderedDict([(u'bar', OrderedDict([(u'type', [OrderedDict([(u'@foobar', u'1')]), OrderedDict([(u'@foobar', u'2')])])]))])

>>> result['foo']['bar']

OrderedDict([(u'type', [OrderedDict([(u'@foobar', u'1')]), OrderedDict([(u'@foobar', u'2')])])])

Removing Data From ElasticSearch

You have to send a DELETE request to

http://[your_host]:9200/[your_index_name_here]

You can also delete a single document:

http://[your_host]:9200/[your_index_name_here]/[your_type_here]/[your_doc_id]

I suggest you to use elastichammer.

After deleting you can look up if the index still exists with the following URL: http://[your_host]:9200/_stats/

Good luck!

Insecure content in iframe on secure page

Based on generality of this question, I think, that you'll need to setup your own HTTPS proxy on some server online. Do the following steps:

  • Prepare your proxy server - install IIS, Apache
  • Get valid SSL certificate to avoid security errors (free from startssl.com for example)
  • Write a wrapper, which will download insecure content (how to below)
  • From your site/app get https://yourproxy.com/?page=http://insecurepage.com

If you simply download remote site content via file_get_contents or similiar, you can still have insecure links to content. You'll have to find them with regex and also replace. Images are hard to solve, but Ï found workaround here: http://foundationphp.com/tutorials/image_proxy.php


Note: While this solution may have worked in some browsers when it was written in 2014, it no longer works. Navigating or redirecting to an HTTP URL in an iframe embedded in an HTTPS page is not permitted by modern browsers, even if the frame started out with an HTTPS URL.

The best solution I created is to simply use google as the ssl proxy...

https://www.google.com/search?q=%http://yourhttpsite.com&btnI=Im+Feeling+Lucky

Tested and works in firefox.

Other Methods:

  • Use a Third party such as embed.ly (but it it really only good for well known http APIs).

  • Create your own redirect script on an https page you control (a simple javascript redirect on a relative linked page should do the trick. Something like: (you can use any langauge/method)

    https://example.com That has a iframe linking to...

    https://example.com/utilities/redirect.html Which has a simple js redirect script like...

    document.location.href ="http://thenonsslsite.com";

  • Alternatively, you could add an RSS feed or write some reader/parser to read the http site and display it within your https site.

  • You could/should also recommend to the http site owner that they create an ssl connection. If for no other reason than it increases seo.

Unless you can get the http site owner to create an ssl certificate, the most secure and permanent solution would be to create an RSS feed grabing the content you need (presumably you are not actually 'doing' anything on the http site -that is to say not logging in to any system).

The real issue is that having http elements inside a https site represents a security issue. There are no completely kosher ways around this security risk so the above are just current work arounds.

Note, that you can disable this security measure in most browsers (yourself, not for others). Also note that these 'hacks' may become obsolete over time.

How do I tokenize a string sentence in NLTK?

This is actually on the main page of nltk.org:

>>> import nltk
>>> sentence = """At eight o'clock on Thursday morning
... Arthur didn't feel very good."""
>>> tokens = nltk.word_tokenize(sentence)
>>> tokens
['At', 'eight', "o'clock", 'on', 'Thursday', 'morning',
'Arthur', 'did', "n't", 'feel', 'very', 'good', '.']

Why use pip over easy_install?

Another—as of yet unmentioned—reason for favoring pip is because it is the new hotness and will continue to be used in the future.

The infographic below—from the Current State of Packaging section in the The Hitchhiker's Guide to Packaging v1.0—shows that setuptools/easy_install will go away in the future.

enter image description here

Here's another infographic from distribute's documentation showing that Setuptools and easy_install will be replaced by the new hotness—distribute and pip. While pip is still the new hotness, Distribute merged with Setuptools in 2013 with the release of Setuptools v0.7.

enter image description here

How to grep for two words existing on the same line?

you could use awk. like this...

cat <yourFile> | awk '/word1/ && /word2/'

Order is not important. So if you have a file and...

a file named , file1 contains:

word1 is in this file as well as word2
word2 is in this file as well as word1
word4 is in this file as well as word1
word5 is in this file as well as word2

then,

/tmp$ cat file1| awk '/word1/ && /word2/'

will result in,

word1 is in this file as well as word2
word2 is in this file as well as word1

yes, awk is slower.

Should __init__() call the parent class's __init__()?

If you need something from super's __init__ to be done in addition to what is being done in the current class's __init__, you must call it yourself, since that will not happen automatically. But if you don't need anything from super's __init__, no need to call it. Example:

>>> class C(object):
        def __init__(self):
            self.b = 1


>>> class D(C):
        def __init__(self):
            super().__init__() # in Python 2 use super(D, self).__init__()
            self.a = 1


>>> class E(C):
        def __init__(self):
            self.a = 1


>>> d = D()
>>> d.a
1
>>> d.b  # This works because of the call to super's init
1
>>> e = E()
>>> e.a
1
>>> e.b  # This is going to fail since nothing in E initializes b...
Traceback (most recent call last):
  File "<pyshell#70>", line 1, in <module>
    e.b  # This is going to fail since nothing in E initializes b...
AttributeError: 'E' object has no attribute 'b'

__del__ is the same way, (but be wary of relying on __del__ for finalization - consider doing it via the with statement instead).

I rarely use __new__. I do all the initialization in __init__.

SQL query with avg and group by

As I understand, you want the average value for each id at each pass. The solution is

SELECT id, pass, avg(value) FROM data_r1
GROUP BY id, pass;

Proper use cases for Android UserManager.isUserAGoat()?

There's a funny named method/constant/whatever in each version of Android.

The only practical use I ever saw was in the Last Call for Google I/O Contest where they asked what it was for a particular version, to see if contestants read the API diff report for each release. The contest had programming problems too, but generally some trivia that could be graded automatically first to get the number of submissions down to reasonable amounts that would be easier to check.

How to open a new form from another form

ok so I used this:

public partial class Form1 : Form
{
    private void Button_Click(object sender, EventArgs e)
    {
        Form2 myForm = new Form2();
        this.Hide();
        myForm.ShowDialog();
        this.Close();
    }
}

This seems to be working fine but the first form is just hidden and it can still generate events. the "this.Close()" is needed to close the first form but if you still want your form to run (and not act like a launcher) you MUST replace it with

this.Show();

Best of luck!

Get first element from a dictionary

For anyone coming to this that wants a linq-less way to get an element from a dictionary

var d = new Dictionary<string, string>();
d.Add("a", "b");
var e = d.GetEnumerator();
e.MoveNext();
var anElement = e.Current;
// anElement/e.Current is a KeyValuePair<string,string>
// where Key = "a", Value = "b"

I'm not sure if this is implementation specific, but if your Dictionary doesn't have any elements, Current will contain a KeyValuePair<string, string> where both the key and value are null.

(I looked at the logic behind linq's First method to come up with this, and tested it via LinqPad 4)

Getting an "ambiguous redirect" error

I got this error when trying to use brace expansion to write output to multiple files.

for example: echo "text" > {f1,f2}.txt results in -bash: {f1,f2}.txt: ambiguous redirect

In this case, use tee to output to multiple files:

echo "text" | tee {f1,f2,...,fn}.txt 1>/dev/null

the 1>/dev/null will prevent the text from being written to stdout

If you want to append to the file(s) use tee -a

Gather multiple sets of columns

It's not at all related to "tidyr" and "dplyr", but here's another option to consider: merged.stack from my "splitstackshape" package, V1.4.0 and above.

library(splitstackshape)
merged.stack(df, id.vars = c("id", "time"), 
             var.stubs = c("Q3.2.", "Q3.3."),
             sep = "var.stubs")
#     id       time .time_1       Q3.2.       Q3.3.
#  1:  1 2009-01-01      1. -0.62645381  1.35867955
#  2:  1 2009-01-01      2.  1.51178117 -0.16452360
#  3:  1 2009-01-01      3.  0.91897737  0.39810588
#  4:  2 2009-01-02      1.  0.18364332 -0.10278773
#  5:  2 2009-01-02      2.  0.38984324 -0.25336168
#  6:  2 2009-01-02      3.  0.78213630 -0.61202639
#  7:  3 2009-01-03      1. -0.83562861  0.38767161
# <<:::SNIP:::>>
# 24:  8 2009-01-08      3. -1.47075238 -1.04413463
# 25:  9 2009-01-09      1.  0.57578135  1.10002537
# 26:  9 2009-01-09      2.  0.82122120 -0.11234621
# 27:  9 2009-01-09      3. -0.47815006  0.56971963
# 28: 10 2009-01-10      1. -0.30538839  0.76317575
# 29: 10 2009-01-10      2.  0.59390132  0.88110773
# 30: 10 2009-01-10      3.  0.41794156 -0.13505460
#     id       time .time_1       Q3.2.       Q3.3.

Can I override and overload static methods in Java?

The very purpose of using the static method is to access the method of a class without creating an instance for it.It will make no sense if we override that method since they will be accessed by classname.method()

how to rotate a bitmap 90 degrees

If you rotate bitmap, 90 180 270 360 is ok but for other degrees canvas will draw bitmap with different size.

So,the best way is

canvas.rotate(degree,rotateCenterPoint.x,rotateCenterPoint.y);  
canvas.drawBitmap(...);
canvas.rotate(-degree,rotateCenterPoint.x,rotateCenterPoint.y);//rotate back

C - Convert an uppercase letter to lowercase

You messed up the second part of your if condition. That should be a <= 90.

Also, FYI, there is a C library function tolower that does this already:

#include <ctype.h>
#include <stdio.h>

int main() {
    putchar(tolower('A'));
}

Disable/Enable Submit Button until all forms have been filled

You can enable and disable the submit button based on the javascript validation below is the validation code. Working Example Here

<script>
function validate() {

var valid = true;
valid = checkEmpty($("#name"));
valid = valid && checkEmail($("#email"));

$("#san-button").attr("disabled",true);
if(valid) {
$("#san-button").attr("disabled",false);
} 
}
function checkEmpty(obj) {
var name = $(obj).attr("name");
$("."+name+"-validation").html(""); 
$(obj).css("border","");
if($(obj).val() == "") {
$(obj).css("border","#FF0000 1px solid");
$("."+name+"-validation").html("Required");
return false;
}

return true; 
}
function checkEmail(obj) {
var result = true;

var name = $(obj).attr("name");
$("."+name+"-validation").html(""); 
$(obj).css("border","");

result = checkEmpty(obj);

if(!result) {
$(obj).css("border","#FF0000 1px solid");
$("."+name+"-validation").html("Required");
return false;
}

var email_regex = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,3})+$/;
result = email_regex.test($(obj).val());

if(!result) {
$(obj).css("border","#FF0000 1px solid");
$("."+name+"-validation").html("Invalid");
return false;
}

return result; 
}
</script>  

Wait some seconds without blocking UI execution

If you do not want to block things and also not want to use multi threading, here is the solution for you: https://msdn.microsoft.com/en-us/library/system.timers.timer(v=vs.110).aspx

The UI Thread is not blocked and the timer waits for 2 seconds before doing something.

Here is the code coming from the link above:

        // Create a timer with a two second interval.
    aTimer = new System.Timers.Timer(2000);
    // Hook up the Elapsed event for the timer. 
    aTimer.Elapsed += OnTimedEvent;
    aTimer.Enabled = true;

    Console.WriteLine("Press the Enter key to exit the program... ");
    Console.ReadLine();
    Console.WriteLine("Terminating the application...");

How to Convert Int to Unsigned Byte and Back

The solution works fine (thanks!), but if you want to avoid casting and leave the low level work to the JDK, you can use a DataOutputStream to write your int's and a DataInputStream to read them back in. They are automatically treated as unsigned bytes then:

For converting int's to binary bytes;

ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
int val = 250;
dos.write(byteVal);
...
dos.flush();

Reading them back in:

// important to use a (non-Unicode!) encoding like US_ASCII or ISO-8859-1,
// i.e., one that uses one byte per character
ByteArrayInputStream bis = new ByteArrayInputStream(
   bos.toString("ISO-8859-1").getBytes("ISO-8859-1"));
DataInputStream dis = new DataInputStream(bis);
int byteVal = dis.readUnsignedByte();

Esp. useful for handling binary data formats (e.g. flat message formats, etc.)

Dynamically updating css in Angular 2

Check working Demo here

import {Component,bind} from 'angular2/core';
import {bootstrap} from 'angular2/platform/browser';
import {FORM_DIRECTIVES} from 'angular2/form';

import {Directive, ElementRef, Renderer, Input,ViewChild,AfterViewInit} from 'angular2/core';

@Component({
  selector: 'my-app',
    template: `
    <style>
       .myStyle{
        width:200px;
        height:100px;
        border:1px solid;
        margin-top:20px;
        background:gray;
        text-align:center;
       }
    </style>

          <div [class.myStyle]="my" [style.background-color]="randomColor" [style.width]="width+'px'" [style.height]="height+'px'"> my width={{width}} & height={{height}}</div>
    `,
    directives: []
})

export class AppComponent {
  my:boolean=true;
  width:number=200px;
  height:number=100px;
  randomColor;
  randomNumber;
  intervalId;
  textArray = [
    'blue',
    'green',
    'yellow',
    'orange',
    'pink'
  ];


  constructor() 
  {
    this.start();
  }

      start()
      { 
        this.randomNumber = Math.floor(Math.random()*this.textArray.length);
        this.randomColor=this.textArray[this.randomNumber];
        console.log('start' + this.randomNumber);
        this.intervalId = setInterval(()=>{
         this.width=this.width+20;
         this.height=this.height+10;
         console.log(this.width +" "+ this.height)
         if(this.width==300)
         {
           this.stop();
         }

        }, 1000);
      }
      stop()
      {
        console.log('stop');
        clearInterval(this.intervalId);
        this.width=200;
        this.height=100;
        this.start();

      }
 }

bootstrap(AppComponent, []);

How to get full path of selected file on change of <input type=‘file’> using javascript, jquery-ajax?

Did you mean this?

$('#i_file').change( function(event) {
var tmppath = URL.createObjectURL(event.target.files[0]);
    $("img").fadeIn("fast").attr('src',tmppath);       
});

Inserting a string into a list without getting split into characters

You have to add another list:

list[:0]=['foo']

How to select all records from one table that do not exist in another table?

Here's what worked best for me.

SELECT *
FROM @T1
EXCEPT
SELECT a.*
FROM @T1 a
JOIN @T2 b ON a.ID = b.ID

This was more than twice as fast as any other method I tried.

How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ?

An addition to the other answers concerning object comparison:

== compares objects using the name of the object and their values. If two objects are of the same type and have the same member values, $a == $b yields true.

=== compares the internal object id of the objects. Even if the members are equal, $a !== $b if they are not exactly the same object.

class TestClassA {
    public $a;
}

class TestClassB {
    public $a;
}

$a1 = new TestClassA();
$a2 = new TestClassA();
$b = new TestClassB();

$a1->a = 10;
$a2->a = 10;
$b->a = 10;

$a1 == $a1;
$a1 == $a2;  // Same members
$a1 != $b;   // Different classes

$a1 === $a1;
$a1 !== $a2; // Not the same object

Restoring Nuget References?

In case this helps someone, for me, none of the above was sufficient. I still couldn't build, VS still couldn't find the references. The key was simply to close and reopen the solution after restoring the packages.

Here's the scenario (using Visual Studio 2012):

You open a Solution that has missing packages. The references show that VS can't find them. There are many ways to restore the missing packages, including

  • building a solution that is set to auto-restore
  • opening the Package Manager Console and clicking the nice "Restore" button
  • doing nuget restore if you have the command line nuget installed

But no matter what the approach, those references will still be shown as missing. And when you build it will fail. Sigh. However if you close the solution and re-open it, now VS checks those nice <HintPath>s again, finds that the packages are back where they belong, and all is well with the world.

Update

Is Visual Studio still not seeing that you have the package? Still showing a reference that it can't resolve? Make sure that the version of package you restored is exactly the same as the <HintPath> in your .csproj file. Even a minor bug fix number (e.g. 1.10.1 to 1.10.2) will cause the reference to fail. You can fix this either by directly editing your csproj xml, or else by removing the reference and making a new one pointing at the newly-restored version in the packages directory.

How to run C program on Mac OS X using Terminal?

1) First you need to install a GCC Compiler for mac (Google it and install it from the net )

2) Remember the path where you are storing the C file

3) Go to Terminal and set the path

e.g- if you have saved in a new folder ProgramC in Document folder

   then type this in Terminal
    cd Document
    cd ProgramC

4) Now you can see that you are in folder where you have saved your C program (let you saved your program as Hello.c)

5) Now Compile your program

   make Hello
   ./hello

How to allow Cross domain request in apache2

Enable mod_headers in Apache2 to be able to use Header directive :

a2enmod headers

How to create own dynamic type or dynamic object in C#?

ExpandoObject is what are you looking for.

dynamic MyDynamic = new ExpandoObject(); // note, the type MUST be dynamic to use dynamic invoking.
MyDynamic.A = "A";
MyDynamic.B = "B";
MyDynamic.C = "C";
MyDynamic.TheAnswerToLifeTheUniverseAndEverything = 42;

Python pip install module is not found. How to link python to pip location?

Here is something I learnt after a long time of having issues with pip when I had several versions of Python installed (valid especially for OS X users which are probably using brew to install python blends.)

I assume that most python developers do have at the beginning of their scripts:

#!/bin/env python

You may be surprised to find out that this is not necessarily the same python as the one you run from the command line >python

To be sure you install the package using the correct pip instance for your python interpreter you need to run something like:

>/bin/env python -m pip install --upgrade mymodule

Detect click outside React component

Hook implementation based on Tanner Linsley's excellent talk at JSConf Hawaii 2020:

useOuterClick Hook API

const Client = () => {
  const innerRef = useOuterClick(ev => {/*what you want to do on outer click*/});
  return <div ref={innerRef}> Inside </div> 
};

Implementation

function useOuterClick(callback) {
  const callbackRef = useRef(); // initialize mutable callback ref
  const innerRef = useRef(); // returned to client, who sets the "border" element

  // update callback on each render, so second useEffect has most recent callback
  useEffect(() => { callbackRef.current = callback; });
  useEffect(() => {
    document.addEventListener("click", handleClick);
    return () => document.removeEventListener("click", handleClick);
    function handleClick(e) {
      if (innerRef.current && callbackRef.current && 
        !innerRef.current.contains(e.target)
      ) callbackRef.current(e);
    }
  }, []); // no dependencies -> stable click listener
      
  return innerRef; // convenience for client (doesn't need to init ref himself) 
}

Here is a working example:

_x000D_
_x000D_
/*
  Custom Hook
*/
function useOuterClick(callback) {
  const innerRef = useRef();
  const callbackRef = useRef();

  // set current callback in ref, before second useEffect uses it
  useEffect(() => { // useEffect wrapper to be safe for concurrent mode
    callbackRef.current = callback;
  });

  useEffect(() => {
    document.addEventListener("click", handleClick);
    return () => document.removeEventListener("click", handleClick);

    // read most recent callback and innerRef dom node from refs
    function handleClick(e) {
      if (
        innerRef.current && 
        callbackRef.current &&
        !innerRef.current.contains(e.target)
      ) {
        callbackRef.current(e);
      }
    }
  }, []); // no need for callback + innerRef dep
  
  return innerRef; // return ref; client can omit `useRef`
}

/*
  Usage 
*/
const Client = () => {
  const [counter, setCounter] = useState(0);
  const innerRef = useOuterClick(e => {
    // counter state is up-to-date, when handler is called
    alert(`Clicked outside! Increment counter to ${counter + 1}`);
    setCounter(c => c + 1);
  });
  return (
    <div>
      <p>Click outside!</p>
      <div id="container" ref={innerRef}>
        Inside, counter: {counter}
      </div>
    </div>
  );
};

ReactDOM.render(<Client />, document.getElementById("root"));
_x000D_
#container { border: 1px solid red; padding: 20px; }
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.12.0/umd/react.production.min.js" integrity="sha256-Ef0vObdWpkMAnxp39TYSLVS/vVUokDE8CDFnx7tjY6U=" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.12.0/umd/react-dom.production.min.js" integrity="sha256-p2yuFdE8hNZsQ31Qk+s8N+Me2fL5cc6NKXOC0U9uGww=" crossorigin="anonymous"></script>
<script> var {useRef, useEffect, useCallback, useState} = React</script>
<div id="root"></div>
_x000D_
_x000D_
_x000D_

Explanation

useOuterClick makes use of mutable refs to create a lean API for the Client. A callback can be set without having to memoize it via useCallback. The callback body still has access to the most recent props and state (no stale closure values).

Note for iOS users

iOS treats only certain elements as clickable. To circumvent this behavior, choose a different outer click listener than document - nothing upwards including body. E.g. you could add a listener on the React root div in above example and expand its height (height: 100vh or similar) to catch all outside clicks. Source: quirksmode.org

How to make a script wait for a pressed key?

I don't know of a platform independent way of doing it, but under Windows, if you use the msvcrt module, you can use its getch function:

import msvcrt
c = msvcrt.getch()
print 'you entered', c

mscvcrt also includes the non-blocking kbhit() function to see if a key was pressed without waiting (not sure if there's a corresponding curses function). Under UNIX, there is the curses package, but not sure if you can use it without using it for all of the screen output. This code works under UNIX:

import curses
stdscr = curses.initscr()
c = stdscr.getch()
print 'you entered', chr(c)
curses.endwin()

Note that curses.getch() returns the ordinal of the key pressed so to make it have the same output I had to cast it.

WooCommerce - get category for product page

<?php
   $terms = get_the_terms($product->ID, 'product_cat');
      foreach ($terms as $term) {

        $product_cat = $term->name;
           echo $product_cat;
             break;
  }
 ?>

.m2 , settings.xml in Ubuntu

Quoted from http://maven.apache.org/settings.html:

There are two locations where a settings.xml file may live:

The Maven install: $M2_HOME/conf/settings.xml

A user's install: ${user.home}/.m2/settings.xml

So, usually for a specific user you edit

/home/*username*/.m2/settings.xml

To set environment for all local users, you might think about changing the first path.

How can I wait In Node.js (JavaScript)? l need to pause for a period of time

let co = require('co');
const sleep = ms => new Promise(res => setTimeout(res, ms));

co(function*() {
    console.log('Welcome to My Console,');
    yield sleep(3000);
    console.log('Blah blah blah blah extra-blah');
});

This code above is the side effect of the solving Javascript's asynchronous callback hell problem. This is also the reason I think that makes Javascript a useful language in the backend. Actually this is the most exciting improvement introduced to modern Javascript in my opinion. To fully understand how it works, how generator works needs to be fully understood. The function keyword followed by a * is called a generator function in modern Javascript. The npm package co provided a runner function to run a generator.

Essentially generator function provided a way to pause the execution of a function with yield keyword, at the same time, yield in a generator function made it possible to exchange information between inside the generator and the caller. This provided a mechanism for the caller to extract data from a promise from an asynchronous call and to pass the resolved data back to the generator. Effectively, it makes an asynchronous call synchronous.

When & why to use delegates?

I've just go my head around these, and so I'll share an example as you already have descriptions but at the moment one advantage I see is to get around the Circular Reference style warnings where you can't have 2 projects referencing each other.

Let's assume an application downloads an XML, and then saves the XML to a database.

I have 2 projects here which build my solution: FTP and a SaveDatabase.

So, our application starts by looking for any downloads and downloading the file(s) then it calls the SaveDatabase project.

Now, our application needs to notify the FTP site when a file is saved to the database by uploading a file with Meta data (ignore why, it's a request from the owner of the FTP site). The issue is at what point and how? We need a new method called NotifyFtpComplete() but in which of our projects should it be saved too - FTP or SaveDatabase? Logically, the code should live in our FTP project. But, this would mean our NotifyFtpComplete will have to be triggered or, it will have to wait until the save is complete, and then query the database to ensure it is in there. What we need to do is tell our SaveDatabase project to call the NotifyFtpComplete() method direct but we can't; we'd get a ciruclar reference and the NotifyFtpComplete() is a private method. What a shame, this would have worked. Well, it can.

During our application's code, we would have passed parameters between methods, but what if one of those parameters was the NotifyFtpComplete method. Yup, we pass the method, with all of the code inside as well. This would mean we could execute the method at any point, from any project. Well, this is what the delegate is. This means, we can pass the NotifyFtpComplete() method as a parameter to our SaveDatabase() class. At the point it saves, it simply executes the delegate.

See if this crude example helps (pseudo code). We will also assume that the application starts with the Begin() method of the FTP class.

class FTP
{
    public void Begin()
    {
        string filePath = DownloadFileFromFtpAndReturnPathName();

        SaveDatabase sd = new SaveDatabase();
        sd.Begin(filePath, NotifyFtpComplete());
    }

    private void NotifyFtpComplete()
    {
        //Code to send file to FTP site
    }
}


class SaveDatabase
{
    private void Begin(string filePath, delegateType NotifyJobComplete())
    {
        SaveToTheDatabase(filePath);

        /* InvokeTheDelegate - 
         * here we can execute the NotifyJobComplete
         * method at our preferred moment in the application,
         * despite the method being private and belonging
         * to a different class.
         */
        NotifyJobComplete.Invoke();
    }
}

So, with that explained, we can do it for real now with this Console Application using C#

using System;

namespace ConsoleApplication1
{
    /* I've made this class private to demonstrate that 
    * the SaveToDatabase cannot have any knowledge of this Program class.
    */
    class Program
    {
        static void Main(string[] args)
        {
            //Note, this NotifyDelegate type is defined in the SaveToDatabase project
            NotifyDelegate nofityDelegate = new NotifyDelegate(NotifyIfComplete);

            SaveToDatabase sd = new SaveToDatabase();            
            sd.Start(nofityDelegate);
            Console.ReadKey();
        }

        /* this is the method which will be delegated -
         * the only thing it has in common with the NofityDelegate
         * is that it takes 0 parameters and that it returns void.
         * However, it is these 2 which are essential.
         * It is really important to notice that it writes
         * a variable which, due to no constructor,
         * has not yet been called (so _notice is not initialized yet).
         */ 
    private static void NotifyIfComplete()
    {
        Console.WriteLine(_notice);
    }

    private static string _notice = "Notified";
    }


    public class SaveToDatabase
    {
        public void Start(NotifyDelegate nd)
        {
            /* I shouldn't write to the console from here, 
             * just for demonstration purposes
             */
            Console.WriteLine("SaveToDatabase Complete");
            Console.WriteLine(" ");
            nd.Invoke();
        }
    }
    public delegate void NotifyDelegate();
}

I suggest you step through the code and see when _notice is called and when the method (delegate) is called as this, I hope, will make things very clear.

However, lastly, we can make it more useful by changing the delegate type to include a parameter.

using System.Text;

namespace ConsoleApplication1
{
    /* I've made this class private to demonstrate that the SaveToDatabase
     * cannot have any knowledge of this Program class.
     */
    class Program
    {
        static void Main(string[] args)
        {
            SaveToDatabase sd = new SaveToDatabase();
            /* Please note, that although NotifyIfComplete()
         * takes a string parameter, we do not declare it,
         * all we want to do is tell C# where the method is
         * so it can be referenced later,
         * we will pass the parameter later.
         */
            var notifyDelegateWithMessage = new NotifyDelegateWithMessage(NotifyIfComplete);

            sd.Start(notifyDelegateWithMessage );

            Console.ReadKey();
        }

        private static void NotifyIfComplete(string message)
        {
            Console.WriteLine(message);
        }
    }


    public class SaveToDatabase
    {
        public void Start(NotifyDelegateWithMessage nd)
        {
                        /* To simulate a saving fail or success, I'm just going
         * to check the current time (well, the seconds) and
         * store the value as variable.
         */
            string message = string.Empty;
            if (DateTime.Now.Second > 30)
                message = "Saved";
            else
                message = "Failed";

            //It is at this point we pass the parameter to our method.
            nd.Invoke(message);
        }
    }

    public delegate void NotifyDelegateWithMessage(string message);
}

Matplotlib transparent line plots

After I plotted all the lines, I was able to set the transparency of all of them as follows:

for l in fig_field.gca().lines:
    l.set_alpha(.7)

EDIT: please see Joe's answer in the comments.

This table does not contain a unique column. Grid edit, checkbox, Edit, Copy and Delete features are not available

This for me was resolved by re-exporting the data from original source DB and then importing it into the mirror DB.

Setting a minimum/maximum character count for any character using a regular expression

Like this: .

The . means any character except newline (which sometimes is but often isn't included, check your regex flavour).

You can rewrite your expression as ^.{1,35}$, which should match any line of length 1-35.

ORA-00984: column not allowed here

Replace double quotes with single ones:

INSERT
INTO    MY.LOGFILE
        (id,severity,category,logdate,appendername,message,extrainfo)
VALUES  (
       'dee205e29ec34',
       'FATAL',
       'facade.uploader.model',
       '2013-06-11 17:16:31',
       'LOGDB',
       NULL,
       NULL
       )

In SQL, double quotes are used to mark identifiers, not string constants.

Is there a way to run Bash scripts on Windows?

Best option? Windows 10. Native Bash support!

git - remote add origin vs remote set-url origin

To add a new remote, use the git remote add command on the terminal, in the directory your repository is stored at.

The git remote set-url command changes an existing remote repository URL.

So basicly, remote add is to add a new one, remote set-url is to update an existing one

Default SQL Server Port

The default port of SQL server is 1433.

Generating a unique machine id

What about just using the UniqueID of the processor?

How to make a phone call using intent in Android?

You can use this as well:

String uri = "tel:" + posted_by.replaceAll("[^0-9|\\+]", "");

(Deep) copying an array using jQuery

I realize you're looking for a "deep" copy of an array, but if you just have a single level array you can use this:

Copying a native JS Array is easy. Use the Array.slice() method which creates a copy of part/all of the array.

var foo = ['a','b','c','d','e'];
var bar = foo.slice();

now foo and bar are 5 member arrays of 'a','b','c','d','e'

of course bar is a copy, not a reference... so if you did this next...

bar.push('f');
alert('foo:' + foo.join(', '));
alert('bar:' + bar.join(', '));

you would now get:

foo:a, b, c, d, e
bar:a, b, c, d, e, f

How to refresh Android listview?

Just use myArrayList.remove(position); inside a listener:

  myListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override public void onItemClick(AdapterView<?> parent, android.view.View view, int position, long id) {
           myArrayList.remove(position);
           myArrayAdapter.notifyDataSetChanged();
        }
    });

What do all of Scala's symbolic operators mean?

Scala inherits most of Java's arithmetic operators. This includes bitwise-or | (single pipe character), bitwise-and &, bitwise-exclusive-or ^, as well as logical (boolean) or || (two pipe characters) and logical-and &&. Interestingly, you can use the single character operators on boolean, so the java'ish logical operators are totally redundant:

true && true   // valid
true & true    // valid as well

3 & 4          // bitwise-and (011 & 100 yields 000)
3 && 4         // not valid

As pointed out in another post, calls ending in an equals sign =, are resolved (if a method with that name does not exist!) by a reassignment:

var x = 3
x += 1         // `+=` is not a method in `int`, Scala makes it `x = x + 1`

This 'double-check' makes it possible, to easily exchange a mutable for an immutable collection:

val m = collection.mutable.Set("Hallo")   // `m` a val, but holds mutable coll
var i = collection.immutable.Set("Hallo") // `i` is a var, but holds immutable coll

m += "Welt" // destructive call m.+=("Welt")
i += "Welt" // re-assignment i = i + "Welt" (creates a new immutable Set)

What's the difference between "super()" and "super(props)" in React when using es6 classes?

There is only one reason when one needs to pass props to super():

When you want to access this.props in constructor.

Passing:

class MyComponent extends React.Component {    
    constructor(props) {
        super(props)

        console.log(this.props)
        // -> { icon: 'home', … }
    }
}

Not passing:

class MyComponent extends React.Component {    
    constructor(props) {
        super()

        console.log(this.props)
        // -> undefined

        // Props parameter is still available
        console.log(props)
        // -> { icon: 'home', … }
    }

    render() {
        // No difference outside constructor
        console.log(this.props)
        // -> { icon: 'home', … }
    }
}

Note that passing or not passing props to super has no effect on later uses of this.props outside constructor. That is render, shouldComponentUpdate, or event handlers always have access to it.

This is explicitly said in one Sophie Alpert's answer to a similar question.


The documentation—State and Lifecycle, Adding Local State to a Class, point 2—recommends:

Class components should always call the base constructor with props.

However, no reason is provided. We can speculate it is either because of subclassing or for future compatibility.

(Thanks @MattBrowne for the link)

How to reload apache configuration for a site without restarting apache?

It should be possible using the command

sudo /etc/init.d/apache2 reload

I hope that helps.

Best practices for catching and re-throwing .NET exceptions

You may also use:

try
{
// Dangerous code
}
finally
{
// clean up, or do nothing
}

And any exceptions thrown will bubble up to the next level that handles them.

Can you call ko.applyBindings to bind a partial view?

ko.applyBindings accepts a second parameter that is a DOM element to use as the root.

This would let you do something like:

<div id="one">
  <input data-bind="value: name" />
</div>

<div id="two">
  <input data-bind="value: name" />
</div>

<script type="text/javascript">
  var viewModelA = {
     name: ko.observable("Bob")
  };

  var viewModelB = {
     name: ko.observable("Ted")
  };

  ko.applyBindings(viewModelA, document.getElementById("one"));
  ko.applyBindings(viewModelB, document.getElementById("two"));
</script>

So, you can use this technique to bind a viewModel to the dynamic content that you load into your dialog. Overall, you just want to be careful not to call applyBindings multiple times on the same elements, as you will get multiple event handlers attached.

Stored procedure with default parameters

I'd do this one of two ways. Since you're setting your start and end dates in your t-sql code, i wouldn't ask for parameters in the stored proc

Option 1

Create Procedure [Test] AS
    DECLARE @StartDate varchar(10)
    DECLARE @EndDate varchar(10)
    Set @StartDate = '201620' --Define start YearWeek
    Set @EndDate  = (SELECT CAST(DATEPART(YEAR,getdate()) AS varchar(4)) + CAST(DATEPART(WEEK,getdate())-1 AS varchar(2)))

SELECT 
*
FROM
    (SELECT DISTINCT [YEAR],[WeekOfYear] FROM [dbo].[DimDate] WHERE [Year]+[WeekOfYear] BETWEEN @StartDate AND @EndDate ) dimd
    LEFT JOIN [Schema].[Table1] qad ON (qad.[Year]+qad.[Week of the Year]) = (dimd.[Year]+dimd.WeekOfYear)

Option 2

Create Procedure [Test] @StartDate varchar(10),@EndDate varchar(10) AS

SELECT 
*
FROM
    (SELECT DISTINCT [YEAR],[WeekOfYear] FROM [dbo].[DimDate] WHERE [Year]+[WeekOfYear] BETWEEN @StartDate AND @EndDate ) dimd
    LEFT JOIN [Schema].[Table1] qad ON (qad.[Year]+qad.[Week of the Year]) = (dimd.[Year]+dimd.WeekOfYear)

Then run exec test '2016-01-01','2016-01-25'

Class not registered Error

The problem is that the DLL is registered on the 32 bit version of the windows registry, and the application is using the 64 bit version.

Solution: Go into the Project Properties, Compile tab and click "Advanced Compile Options...". Change "Target CPU" to x86, click OK, save and try again.

Source: http://www.theogray.com/blog/2009/10/comexception-regdbeclassnotreg-on-64-bit-windows

Has worked for me with an VB 6 COM DLL invoked from a .Net 4 Winforms application

How to determine if a String has non-alphanumeric characters?

string.matches("^\\W*$"); should do what you want, but it does not include whitespace. string.matches("^(?:\\W|\\s)*$"); does match whitespace as well.

Why an interface can not implement another interface?

Interface is like an abstraction that is not providing any functionality. Hence It does not 'implement' but extend the other abstractions or interfaces.

Correct way to quit a Qt program?

You can call qApp.exit();. I always use that and never had a problem with it.

If you application is a command line application, you might indeed want to return an exit code. It's completely up to you what the code is.

Global Angular CLI version greater than local version

I'm not fluent in English

but if I understand the problem, is it that locally in the project you have an older version of CLI than globally?

And would you like to use this global newer instead of the local older one?

If so, a very simple method is enough to run in the project directory npm link @angular/cli

more in the subject on the page: https://docs.npmjs.com/cli/link

React ignores 'for' attribute of the label element

Yes, for react,

for becomes htmlFor

class becomes className

etc.

see full list of how HTML attributes are changed here:

https://facebook.github.io/react/docs/dom-elements.html

How to make a custom LinkedIn share button

LinkedIn has updated their api and the sharing url's no longer works. Now you can only use the url query parameter. Any other parameter is going to be removed from the url by LinkedIn.

Now you're forced to use oAuth and interact with the linkedin API to share content on behalf of a user.

Form/JavaScript not working on IE 11 with error DOM7011

In my case, this exception was being caused by an unsecure ajax call on an SSL enabled site. Specifically: my url was 'http://...' instead of 'https://...'. I just replaced it with '//...'.

To me, the error was misleading, and hopefully this may help anyone landing here after searching for the same error.

How do I check for vowels in JavaScript?

function isVowel(char)
{
  if (char.length == 1)
  {
    var vowels = "aeiou";
    var isVowel = vowels.indexOf(char) >= 0 ? true : false;

    return isVowel;
  }
}

Basically it checks for the index of the character in the string of vowels. If it is a consonant, and not in the string, indexOf will return -1.

No module named setuptools

The question mentions Windows, and the accepted answer also works for Ubuntu, but for those who found this question coming from a Redhat flavor of Linux, this did the trick:

sudo yum install -y python-setuptools

How to calculate combination and permutation in R?

It might be that the package "Combinations" is not updated anymore and does not work with a recent version of R (I was also unable to install it on R 2.13.1 on windows). The package "combinat" installs without problem for me and might be a solution for you depending on what exactly you're trying to do.

Using varchar(MAX) vs TEXT on SQL Server

  • Basic Definition

TEXT and VarChar(MAX) are Non-Unicode large Variable Length character data type, which can store maximum of 2147483647 Non-Unicode characters (i.e. maximum storage capacity is: 2GB).

  • Which one to Use?

As per MSDN link Microsoft is suggesting to avoid using the Text datatype and it will be removed in a future versions of Sql Server. Varchar(Max) is the suggested data type for storing the large string values instead of Text data type.

  • In-Row or Out-of-Row Storage

Data of a Text type column is stored out-of-row in a separate LOB data pages. The row in the table data page will only have a 16 byte pointer to the LOB data page where the actual data is present. While Data of a Varchar(max) type column is stored in-row if it is less than or equal to 8000 byte. If Varchar(max) column value is crossing the 8000 bytes then the Varchar(max) column value is stored in a separate LOB data pages and row will only have a 16 byte pointer to the LOB data page where the actual data is present. So In-Row Varchar(Max) is good for searches and retrieval.

  • Supported/Unsupported Functionalities

Some of the string functions, operators or the constructs which doesn’t work on the Text type column, but they do work on VarChar(Max) type column.

  1. = Equal to Operator on VarChar(Max) type column
  2. Group by clause on VarChar(Max) type column

    • System IO Considerations

As we know that the VarChar(Max) type column values are stored out-of-row only if the length of the value to be stored in it is greater than 8000 bytes or there is not enough space in the row, otherwise it will store it in-row. So if most of the values stored in the VarChar(Max) column are large and stored out-of-row, the data retrieval behavior will almost similar to the one that of the Text type column.

But if most of the values stored in VarChar(Max) type columns are small enough to store in-row. Then retrieval of the data where LOB columns are not included requires the more number of data pages to read as the LOB column value is stored in-row in the same data page where the non-LOB column values are stored. But if the select query includes LOB column then it requires less number of pages to read for the data retrieval compared to the Text type columns.

Conclusion

Use VarChar(MAX) data type rather than TEXT for good performance.

Source

What is __future__ in Python used for and how/when to use it, and how it works

It can be used to use features which will appear in newer versions while having an older release of Python.

For example

>>> from __future__ import print_function

will allow you to use print as a function:

>>> print('# of entries', len(dictionary), file=sys.stderr)

Scrolling a div with jQuery

This worked for me:

<html>
<head>
<title>scroll</title>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" type="text/javascript"></script>

</head>
<body>

<style>
div.container {
  overflow:hidden;
  width:200px;
  height:200px;
}
div.content {
  position:relative;
  width:200px;
  height:200px;  
  overflow:hidden;
  top:0;
}
</style>

<div class="container">
  <p>
    <a href="javascript:up();"><img src="/images/img_flecha_left.png" class="up" /></a>
    <a href="javascript:down();"><img src="/images/img_flecha_left.png" class="down" /></a>   

  </p>
  <div class="content">
    <p>Hello World</p><p>Hello World</p>
    <p>Hello World</p>
    <p>Hello World</p>
    <p>Hello World</p>
    <p>Hello World</p>
    <p>Hello World</p>
    <p>Hello World</p>
    <p>Hello World</p>
  </div>
</div>

<script>
function up() {
    var topVal = $(".content").css("top"); //alert(topVal);
    var val=parseInt(topVal.replace("px",""));
    val=val-20;
    $(".content").css("top", val+"px");    
}
function down() {
    var topVal = $(".content").css("top"); //alert(topVal);
    var val=parseInt(topVal.replace("px",""));
    val=val+20;
    $(".content").css("top", val+"px");  
}
</script>
</body>
</html>

Android - How to download a file from a webserver

Here is the code help you to download file from server at the same time you can see the progress of downloading on your status bar.

See the functionality in below image of my code:

enter image description here enter image description here

STEP - 1 : Create on DownloadFileFromURL.java class file to download file content from server. Here i create an asynchronous task to download file.

public class DownloadFileFromURL extends AsyncTask<String, Integer, String> {

private NotificationManager mNotifyManager;
private NotificationCompat.Builder build;
private File fileurl;
int id = 123;
OutputStream output;
private Context context;
private String selectedDate;
private String ts = "";

public DownloadFileFromURL(Context context, String selectedDate) {
    this.context = context;
    this.selectedDate = selectedDate;

}

protected void onPreExecute() {
    super.onPreExecute();

    mNotifyManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    build = new NotificationCompat.Builder(context);
    build.setContentTitle("Download")
            .setContentText("Download in progress")
            .setChannelId(id + "")
            .setAutoCancel(false)
            .setDefaults(0)
            .setSmallIcon(R.drawable.ic_menu_download);

    // Since android Oreo notification channel is needed.
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel channel = new NotificationChannel(id + "",
                "Social Media Downloader",
                NotificationManager.IMPORTANCE_HIGH);
        channel.setDescription("no sound");
        channel.setSound(null, null);
        channel.enableLights(false);
        channel.setLightColor(Color.BLUE);
        channel.enableVibration(false);
        mNotifyManager.createNotificationChannel(channel);

    }
    build.setProgress(100, 0, false);
    mNotifyManager.notify(id, build.build());
    String msg = "Download started";
    //CustomToast.showToast(context,msg);
}

@Override
protected String doInBackground(String... f_url) {
    int count;
    ts = selectedDate.split("T")[0];
    try {
        URL url = new URL(f_url[0]);
        URLConnection conection = url.openConnection();
        conection.connect();
        int lenghtOfFile = conection.getContentLength();

        InputStream input = new BufferedInputStream(url.openStream(),
                8192);
        // Output stream
        output = new FileOutputStream(Environment
                .getExternalStorageDirectory().toString()
                + Const.DownloadPath + ts + ".pdf");
        fileurl = new File(Environment.getExternalStorageDirectory()
                + Const.DownloadPath + ts + ".pdf");
        byte[] data = new byte[1024];

        long total = 0;

        while ((count = input.read(data)) != -1) {
            total += count;
            int cur = (int) ((total * 100) / lenghtOfFile);

            publishProgress(Math.min(cur, 100));
            if (Math.min(cur, 100) > 98) {
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    Log.d("Failure", "sleeping failure");
                }
            }
            Log.i("currentProgress", "currentProgress: " + Math.min(cur, 100) + "\n " + cur);

            output.write(data, 0, count);
        }

        output.flush();

        output.close();
        input.close();

    } catch (Exception e) {
        Log.e("Error: ", e.getMessage());
    }

    return null;
}

protected void onProgressUpdate(Integer... progress) {
    build.setProgress(100, progress[0], false);
    mNotifyManager.notify(id, build.build());
    super.onProgressUpdate(progress);
}

@Override
protected void onPostExecute(String file_url) {
    build.setContentText("Download complete");
    build.setProgress(0, 0, false);
    mNotifyManager.notify(id, build.build());
} }

Note: If you want code with import package then Click Here

Now Step 2: You need to call above ayncronous task on your click event. for example i have set on pdf image icon. To call AsyncTask use below code:

 new DownloadFileFromURL(fContext,filename).execute(serverFileUrl);

Note: Here You can see filename variable in file parameter. This is the name which i use to save my downloaded file in local device. currently i am downloading only pdf file but you can use you url in serverFileUrl parameter.

'setInterval' vs 'setTimeout'

setInterval repeats the call, setTimeout only runs it once.

Debugging Spring configuration

If you use Spring Boot, you can also enable a “debug” mode by starting your application with a --debug flag.

java -jar myapp.jar --debug

You can also specify debug=true in your application.properties.

When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate, and Spring Boot) are configured to output more information. Enabling the debug mode does not configure your application to log all messages with DEBUG level.

Alternatively, you can enable a “trace” mode by starting your application with a --trace flag (or trace=true in your application.properties). Doing so enables trace logging for a selection of core loggers (embedded container, Hibernate schema generation, and the whole Spring portfolio).

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-logging.html

How to remove non-alphanumeric characters?

Sounds like you almost knew what you wanted to do already, you basically defined it as a regex.

preg_replace("/[^A-Za-z0-9 ]/", '', $string);

How to localise a string inside the iOS info.plist file?

For anyone experiencing the problem of the info.plist not being included when trying to add localizations, like in Xcode 9.

You need make the info.plist localiazble by going into it and clicking on the localize button in the file inspector, as shown below.

The info.plist will then be included in the file resources for when you go to add new Localizations.

enter image description here

Determine the data types of a data frame's columns

Simply pass your data frame into the following function:

data_types <- function(frame) {
  res <- lapply(frame, class)
  res_frame <- data.frame(unlist(res))
  barplot(table(res_frame), main="Data Types", col="steelblue", ylab="Number of Features")
}

to produce a plot of all data types in your data frame. For the iris dataset we get the following:

data_types(iris)

enter image description here

How to allow only one radio button to be checked?

Add "name" attribute and keep the name same for all the radio buttons in a form.

i.e.,

<input type="radio" name="test" value="value1"> Value 1
<input type="radio" name="test" value="value2"> Value 2
<input type="radio" name="test" value="value3"> Value 3

Hope that would help.

How do I get the current absolute URL in Ruby on Rails?

If you're using Rails 3.2 or Rails 4 you should use request.original_url to get the current URL.


Documentation for the method is at http://api.rubyonrails.org/classes/ActionDispatch/Request.html#method-i-original_url but if you're curious the implementation is:

def original_url
  base_url + original_fullpath
end

How can I capture the right-click event in JavaScript?

I think that you are looking for something like this:

   function rightclick() {
    var rightclick;
    var e = window.event;
    if (e.which) rightclick = (e.which == 3);
    else if (e.button) rightclick = (e.button == 2);
    alert(rightclick); // true or false, you can trap right click here by if comparison
}

(http://www.quirksmode.org/js/events_properties.html)

And then use the onmousedown even with the function rightclick() (if you want to use it globally on whole page you can do this <body onmousedown=rightclick(); >

Finding the number of non-blank columns in an Excel sheet using VBA

Jean-François Corbett's answer is perfect. To be exhaustive I would just like to add that with some restrictons you could also use UsedRange.Columns.Count or UsedRange.Rows.Count.
The problem is that UsedRange is not always updated when deleting rows/columns (at least until you reopen the workbook).

Send file using POST from a Python script

You may also want to have a look at httplib2, with examples. I find using httplib2 is more concise than using the built-in HTTP modules.

How to filter in NaN (pandas)?

This doesn't work because NaN isn't equal to anything, including NaN. Use pd.isnull(df.var2) instead.

Best way to do a split pane in HTML

One totally different approach is to put things in a grid, such as ui-grid or Kendo's grid, and have the columns be resizable. A downside is that users would not be able to resize the rows, though the row size could be set programmatically.

ValueError when checking if variable is None or numpy.array

If you are trying to do something very similar: a is not None, the same issue comes up. That is, Numpy complains that one must use a.any or a.all.

A workaround is to do:

if not (a is None):
    pass

Not too pretty, but it does the job.

select the TOP N rows from a table

Assuming your page size is 20 record, and you wanna get page number 2, here is how you would do it:

SQL Server, Oracle:

SELECT *   -- <-- pick any columns here from your table, if you wanna exclude the RowNumber
FROM (SELECT ROW_NUMBER OVER(ORDER BY ID DESC) RowNumber, * 
      FROM Reflow  
      WHERE ReflowProcessID = somenumber) t
WHERE RowNumber >= 20 AND RowNumber <= 40    

MySQL:

SELECT * 
FROM Reflow  
WHERE ReflowProcessID = somenumber
ORDER BY ID DESC
LIMIT 20 OFFSET 20

ASP.Net MVC How to pass data from view to controller

In case you don't want/need to post:

@Html.ActionLink("link caption", "actionName", new { Model.Page })  // view's controller
@Html.ActionLink("link caption", "actionName", "controllerName", new { reportID = 1 }, null);

[HttpGet]
public ActionResult actionName(int reportID)
{

Note that the reportID in the new {} part matches reportID in the action parameters, you can add any number of parameters this way, but any more than 2 or 3 (some will argue always) you should be passing a model via a POST (as per other answer)

Edit: Added null for correct overload as pointed out in comments. There's a number of overloads and if you specify both action+controller, then you need both routeValues and htmlAttributes. Without the controller (just caption+action), only routeValues are needed but may be best practice to always specify both.

Converting video to HTML5 ogg / ogv and mpg4

MS Expression Encoder can do mp4/h.264. not sure about ogg though.

How to hide a navigation bar from first ViewController in Swift?

 private func setupView() {
        view.backgroundColor = .white
        navigationController?.setNavigationBarHidden(true, animated: false)
    }

Show a PDF files in users browser via PHP/Perl

    $url ="https://yourFile.pdf";
    $content = file_get_contents($url);

    header('Content-Type: application/pdf');
    header('Content-Length: ' . strlen($content));
    header('Content-Disposition: inline; filename="YourFileName.pdf"');
    header('Cache-Control: private, max-age=0, must-revalidate');
    header('Pragma: public');
    ini_set('zlib.output_compression','0');

    die($content);

Tested and works fine. If you want the file to download instead, replace

    Content-Disposition: inline

with

    Content-Disposition: attachment

How do I left align these Bootstrap form items?

Just add style="text-align: left" to your label.

What is the difference between #import and #include in Objective-C?

IF you #include a file two times in .h files than compiler will give error. But if you #import a file more than once compiler will ignore it.

How to go to a specific element on page?

The standard technique in plugin form would look something like this:

(function($) {
    $.fn.goTo = function() {
        $('html, body').animate({
            scrollTop: $(this).offset().top + 'px'
        }, 'fast');
        return this; // for chaining...
    }
})(jQuery);

Then you could just say $('#div_element2').goTo(); to scroll to <div id="div_element2">. Options handling and configurability is left as an exercise for the reader.

do { ... } while (0) — what is it good for?

It's the only construct in C that you can use to #define a multistatement operation, put a semicolon after, and still use within an if statement. An example might help:

#define FOO(x) foo(x); bar(x)

if (condition)
    FOO(x);
else // syntax error here
    ...;

Even using braces doesn't help:

#define FOO(x) { foo(x); bar(x); }

Using this in an if statement would require that you omit the semicolon, which is counterintuitive:

if (condition)
    FOO(x)
else
    ...

If you define FOO like this:

#define FOO(x) do { foo(x); bar(x); } while (0)

then the following is syntactically correct:

if (condition)
    FOO(x);
else
    ....

How to render string with html tags in Angular 4+?

Use one way flow syntax property binding:

<div [innerHTML]="comment"></div>

From angular docs: "Angular recognizes the value as unsafe and automatically sanitizes it, which removes the <script> tag but keeps safe content such as the <b> element."

Get random sample from list while maintaining ordering of items?

Following code will generate a random sample of size 4:

import random

sample_size = 4
sorted_sample = [
    mylist[i] for i in sorted(random.sample(range(len(mylist)), sample_size))
]

(note: with Python 2, better use xrange instead of range)

Explanation

random.sample(range(len(mylist)), sample_size)

generates a random sample of the indices of the original list.

These indices then get sorted to preserve the ordering of elements in the original list.

Finally, the list comprehension pulls out the actual elements from the original list, given the sampled indices.

github changes not staged for commit

in my case, I needed a

 git add files
 git commit -am 'what I changed'
 git push

the 'a' on the commit was needed.

SQL is null and = null

It's important to note, that NULL doesn't equal NULL.

NULL is not a value, and therefore cannot be compared to another value.

where x is null checks whether x is a null value.

where x = null is checking whether x equals NULL, which will never be true

How can I revert multiple Git commits (already pushed) to a published repository?

git revert HEAD -m 1

In the above code line. "Last argument represents"

  • 1 - reverts one commits. 2 - reverts last commits. n - reverts last n commits

or

git reset --hard siriwjdd

How can I read user input from the console?

I'm not sure what your problem is (since you haven't told us), but I'm guessing at

a = Console.Read();

This will only read one character from your Console.

You can change your program to this. To make it more robust, accept more than 1 char input, and validate that the input is actually a number:

double a, b;
Console.WriteLine("istenen sayiyi sonuna .00 koyarak yaz");
if (double.TryParse(Console.ReadLine(), out a)) {
  b = a * Math.PI;
  Console.WriteLine("Sonuç " + b); 
} else {
  //user gave an illegal input. Handle it here.
}

How to save a plot as image on the disk?

If you open a device using png(), bmp(), pdf() etc. as suggested by Andrie (the best answer), the windows with plots will not pop up open, just *.png, *bmp or *.pdf files will be created. This is convenient in massive calculations, since R can handle only limited number of graphic windows.

However, if you want to see the plots and also have them saved, call savePlot(filename, type) after the plots are drawn and the window containing them is active.

Hide axis and gridlines Highcharts

This has always worked well for me:

yAxes: [{
         ticks: {
                 display: false;
                },

ORA-28040: No matching authentication protocol exception

Adding

SQLNET.ALLOWED_LOGON_VERSION_SERVER = 8

is the perfect solution sql.ora directory ..\product\12.1.0\dbhome_1\NETWORK\ADMIN

How to use paths in tsconfig.json?

This can be set up on your tsconfig.json file, as it is a TS feature.

You can do like this:

"compilerOptions": {
        "baseUrl": "src", // This must be specified if "paths" is.
         ...
        "paths": {
            "@app/*": ["app/*"],
            "@config/*": ["app/_config/*"],
            "@environment/*": ["environments/*"],
            "@shared/*": ["app/_shared/*"],
            "@helpers/*": ["helpers/*"]
        },
        ...

Have in mind that the path where you want to refer to, it takes your baseUrl as the base of the route you are pointing to and it's mandatory as described on the doc.

The character '@' is not mandatory.

After you set it up on that way, you can easily use it like this:

import { Yo } from '@config/index';

the only thing you might notice is that the intellisense does not work in the current latest version, so I would suggest to follow an index convention for importing/exporting files.

https://www.typescriptlang.org/docs/handbook/module-resolution.html#path-mapping

LINK : fatal error LNK1104: cannot open file 'D:\...\MyProj.exe'

the file can be locked because it is being run now. Try killing the process with a task manager.

Check existence of directory and create if doesn't exist

As of April 16, 2015, with the release of R 3.2.0 there's a new function called dir.exists(). To use this function and create the directory if it doesn't exist, you can use:

ifelse(!dir.exists(file.path(mainDir, subDir)), dir.create(file.path(mainDir, subDir)), FALSE)

This will return FALSE if the directory already exists or is uncreatable, and TRUE if it didn't exist but was succesfully created.

Note that to simply check if the directory exists you can use

dir.exists(file.path(mainDir, subDir))

Where is the php.ini file on a Linux/CentOS PC?

In your terminal/console (only Linux, in windows you need Putty)

ssh user@ip
php -i | grep "Loaded Configuration File"

And it will show you something like this Loaded Configuration File => /etc/php.ini.

ALTERNATIVE METHOD

You can make a php file on your website, which run: <?php phpinfo(); ?>, and you can see the php.ini location on the line with: "Loaded Configuration File".

Update This command gives the path right away

cli_php_ini=php -i | grep /.+/php.ini -oE  #ref. https://stackoverflow.com/a/15763333/248616
    php_ini="${cli_php_ini/cli/apache2}"   #replace cli by apache2 ref. https://stackoverflow.com/a/13210909/248616

CSS selector based on element text?

Not with CSS directly, you could set CSS properties via JavaScript based on the internal contents but in the end you would still need to be operating in the definitions of CSS.

What's the fastest way to read a text file line-by-line?

To find the fastest way to read a file line by line you will have to do some benchmarking. I have done some small tests on my computer but you cannot expect that my results apply to your environment.

Using StreamReader.ReadLine

This is basically your method. For some reason you set the buffer size to the smallest possible value (128). Increasing this will in general increase performance. The default size is 1,024 and other good choices are 512 (the sector size in Windows) or 4,096 (the cluster size in NTFS). You will have to run a benchmark to determine an optimal buffer size. A bigger buffer is - if not faster - at least not slower than a smaller buffer.

const Int32 BufferSize = 128;
using (var fileStream = File.OpenRead(fileName))
  using (var streamReader = new StreamReader(fileStream, Encoding.UTF8, true, BufferSize)) {
    String line;
    while ((line = streamReader.ReadLine()) != null)
      // Process line
  }

The FileStream constructor allows you to specify FileOptions. For example, if you are reading a large file sequentially from beginning to end, you may benefit from FileOptions.SequentialScan. Again, benchmarking is the best thing you can do.

Using File.ReadLines

This is very much like your own solution except that it is implemented using a StreamReader with a fixed buffer size of 1,024. On my computer this results in slightly better performance compared to your code with the buffer size of 128. However, you can get the same performance increase by using a larger buffer size. This method is implemented using an iterator block and does not consume memory for all lines.

var lines = File.ReadLines(fileName);
foreach (var line in lines)
  // Process line

Using File.ReadAllLines

This is very much like the previous method except that this method grows a list of strings used to create the returned array of lines so the memory requirements are higher. However, it returns String[] and not an IEnumerable<String> allowing you to randomly access the lines.

var lines = File.ReadAllLines(fileName);
for (var i = 0; i < lines.Length; i += 1) {
  var line = lines[i];
  // Process line
}

Using String.Split

This method is considerably slower, at least on big files (tested on a 511 KB file), probably due to how String.Split is implemented. It also allocates an array for all the lines increasing the memory required compared to your solution.

using (var streamReader = File.OpenText(fileName)) {
  var lines = streamReader.ReadToEnd().Split("\r\n".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
  foreach (var line in lines)
    // Process line
}

My suggestion is to use File.ReadLines because it is clean and efficient. If you require special sharing options (for example you use FileShare.ReadWrite), you can use your own code but you should increase the buffer size.

Spring MVC @PathVariable with dot (.) is getting truncated

The complete solution including email addresses in path names for spring 4.2 is

<bean id="contentNegotiationManager"
    class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
    <property name="favorPathExtension" value="false" />
    <property name="favorParameter" value="true" />
    <property name="mediaTypes">
        <value>
            json=application/json
            xml=application/xml
        </value>
    </property>
</bean>
<mvc:annotation-driven
    content-negotiation-manager="contentNegotiationManager">
    <mvc:path-matching suffix-pattern="false" registered-suffixes-only="true" />
</mvc:annotation-driven>

Add this to the application-xml

How to get ALL child controls of a Windows Forms form of a specific type (Button/Textbox)?

Here's another option for you. I tested it by creating a sample application, I then put a GroupBox and a GroupBox inside the initial GroupBox. Inside the nested GroupBox I put 3 TextBox controls and a button. This is the code I used (even includes the recursion you were looking for)

public IEnumerable<Control> GetAll(Control control,Type type)
{
    var controls = control.Controls.Cast<Control>();

    return controls.SelectMany(ctrl => GetAll(ctrl,type))
                              .Concat(controls)
                              .Where(c => c.GetType() == type);
}

To test it in the form load event I wanted a count of all controls inside the initial GroupBox

private void Form1_Load(object sender, EventArgs e)
{
    var c = GetAll(this,typeof(TextBox));
    MessageBox.Show("Total Controls: " + c.Count());
}

And it returned the proper count each time, so I think this will work perfectly for what you're looking for :)

include external .js file in node.js app

To place an emphasis on what everyone else has been saying var foo in top level does not create a global variable. If you want a global variable then write global.foo. but we all know globals are evil.

If you are someone who uses globals like that in a node.js project I was on I would refactor them away for as there are just so few use cases for this (There are a few exceptions but this isn't one).

// Declare application
var app = require('express').createServer();

// Declare usefull stuff for DB purposes
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var ObjectId = Schema.ObjectId;

require('./models/car.js').make(Schema, mongoose);

in car.js

function make(Schema, mongoose) {
    // Define Car model
    CarSchema = new Schema({
      brand        : String,
      type : String
    });
    mongoose.model('Car', CarSchema);
}

module.exports.make = make;

Android Studio - How to Change Android SDK Path

  1. Click on File menu.
  2. Select Project Structure.
  3. Edit the path in SDK Location text box. From the next time Android Studio will use this location for all your projects.

N.B.: Avoid having spaces in the path as it may sometimes lead to issues.

Default values in a C Struct

While macros and/or functions (as already suggested) will work (and might have other positive effects (i.e. debug hooks)), they are more complex than needed. The simplest and possibly most elegant solution is to just define a constant that you use for variable initialisation:

const struct foo FOO_DONT_CARE = { // or maybe FOO_DEFAULT or something
    dont_care, dont_care, dont_care, dont_care
};
...
struct foo bar = FOO_DONT_CARE;
bar.id = 42;
bar.current_route = new_route;
update(&bar);

This code has virtually no mental overhead of understanding the indirection, and it is very clear which fields in bar you set explicitly while (safely) ignoring those you do not set.

insert datetime value in sql database with c#

It's more standard to use the format yyyy-mm-dd hh:mm:ss (IE: 2009-06-23 19:30:20)

Using that you won't have to worry about the format of the date (MM/DD/YYYY or DD/MM/YYYY). It will work with all of them.

Check if a JavaScript string is a URL

I change the function to Match + make a change here with the slashes and its work: (http:// and https) both

function isValidUrl(userInput) {
    var res = userInput.match(/(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)/g);
    if(res == null)
       return false;
    else
       return true;
}