#Ultraseek | Programs & Examples on Ultraseek

How can I use Python to get the system hostname?

You can use the field nodename and avoid using array indexing:

os.uname().nodename

Although, even the documentation of os.uname suggests using socket.gethostname()

Why is vertical-align: middle not working on my span or div?

Setting the line-height to the same height as it's containing div will also work

DEMO http://jsfiddle.net/kevinPHPkevin/gZXWC/7/

.inner {
    line-height:72px;
    border: 1px solid #000000;
}

Calling one Activity from another in Android

The following code demonstrates how you can start another activity via an intent.

Start the activity with an intent connected to the specified class

Intent i = new Intent(this, ActivityTwo.class);
startActivity(i);

Activities which are started by other Android activities are called sub-activities. This wording makes it easier to describe which activity is meant.

Selenium: WebDriverException:Chrome failed to start: crashed as google-chrome is no longer running so ChromeDriver is assuming that Chrome has crashed

A simple solution that no one else has said but worked for me was not running without sudo or not as root.

Maximum call stack size exceeded error

Have come accross the same issue, coulnd't figured out what's wrong started blaming Babel ;)

Having code not returning any exception in browsers :

if (typeof document.body.onpointerdown !== ('undefined' || null)) {

issue was badly created || (or) part as babel creates its own type check:

function _typeof(obj){if(typeof Symbol==="function"&&_typeof(Symbol.iterator)==="symbol")

so removing

|| null

made babel transpilation worked.

Dynamic height for DIV

set height: auto; If you want to have minimum height to x then you can write

height:auto;
min-height:30px;
height:auto !important;        /* for IE as it does not support min-height */
height:30px;                   /* for IE as it does not support min-height */

How to print out a variable in makefile

As per the GNU Make manual and also pointed by 'bobbogo' in the below answer, you can use info / warning / error to display text.

$(error   text…)
$(warning text…)
$(info    text…)

To print variables,

$(error   VAR is $(VAR))
$(warning VAR is $(VAR))
$(info    VAR is $(VAR))

'error' would stop the make execution, after showing the error string

Hibernate Error executing DDL via JDBC Statement

I got this same error when i was trying to make a table with name "admin". Then I used @Table annotation and gave table a different name like @Table(name = "admins"). I think some words are reserved (like :- keywords in java) and you can not use them.

@Entity
@Table(name = "admins")
public class Admin extends TrackedEntity {

}

forEach is not a function error with JavaScript array

parent.children will return a ~~node list~~ list, technically a html Collection. That is an array like object, but not an array, so you cannot call array functions over it directly. At this context you can use Array.from() to convert that into a real array,

Array.from(parent.children).forEach(child => {
  console.log(child)
})

Removing the remembered login and password list in SQL Server Management Studio

Delete:

C:\Documents and Settings\%Your Username%\Application Data\Microsoft\Microsoft SQL Server\90\Tools\Shell\mru.dat"

List of all unique characters in a string?

Store Unique characters in list

Method 1:

uniue_char = list(set('aaabcabccd'))
#['a', 'b', 'c', 'd']

Method 2: By Loop ( Complex )

uniue_char = []
for c in 'aaabcabccd':
    if not c in uniue_char:
        uniue_char.append(c)
print(uniue_char)
#['a', 'b', 'c', 'd']

Writing html form data to a txt file without the use of a webserver

I know this is old, but it's the first example of saving form data to a txt file I found in a quick search. So I've made a couple edits to the above code that makes it work more smoothly. It's now easier to add more fields, including the radio button as @user6573234 requested.

https://jsfiddle.net/cgeiser/m0j7Lwyt/1/

<!DOCTYPE html>
<html>
<head>
<style>
form * {
  display: block;
  margin: 10px;
}
</style>
<script language="Javascript" >
function download() {
  var filename = window.document.myform.docname.value;
  var name =  window.document.myform.name.value;
  var text =  window.document.myform.text.value;
  var problem =  window.document.myform.problem.value;
  
  var pom = document.createElement('a');
  pom.setAttribute('href', 'data:text/plain;charset=utf-8,' + 
    "Your Name: " + encodeURIComponent(name) + "\n\n" +
    "Problem: " + encodeURIComponent(problem) + "\n\n" +
    encodeURIComponent(text)); 

  pom.setAttribute('download', filename);

  pom.style.display = 'none';
  document.body.appendChild(pom);

  pom.click();

  document.body.removeChild(pom);
}
</script>
</head>
<body>
<form name="myform" method="post" >
  <input type="text" id="docname" value="test.txt" />
  <input type="text" id="name" placeholder="Your Name" />
  <div style="display:unblock">
    Option 1 <input type="radio" value="Option 1" onclick="getElementById('problem').value=this.value; getElementById('problem').show()" style="display:inline" />
    Option 2 <input type="radio" value="Option 2" onclick="getElementById('problem').value=this.value;" style="display:inline" />
    <input type="text" id="problem" />
  </div>
  <textarea rows=3 cols=50 id="text" />Please type in this box. 
When you click the Download button, the contents of this box will be downloaded to your machine at the location you specify. Pretty nifty. </textarea>
  
  <input id="download_btn" type="submit" class="btn" style="width: 125px" onClick="download();" />
  
</form>
</body>
</html>

Git merge with force overwrite

When I tried using -X theirs and other related command switches I kept getting a merge commit. I probably wasn't understanding it correctly. One easy to understand alternative is just to delete the branch then track it again.

git branch -D <branch-name>
git branch --track <branch-name> origin/<branch-name>

This isn't exactly a "merge", but this is what I was looking for when I came across this question. In my case I wanted to pull changes from a remote branch that were force pushed.

get client time zone from browser

Here is a jsfiddle

It provides the abbreviation of the current user timezone.

Here is the code sample

var tz = jstz.determine();
console.log(tz.name());
console.log(moment.tz.zone(tz.name()).abbr(new Date().getTime()));

How does the Spring @ResponseBody annotation work?

The first basic thing to understand is the difference in architectures.

One end you have the MVC architecture, which is based on your normal web app, using web pages, and the browser makes a request for a page:

Browser <---> Controller <---> Model
               |      |
               +-View-+

The browser makes a request, the controller (@Controller) gets the model (@Entity), and creates the view (JSP) from the model and the view is returned back to the client. This is the basic web app architecture.

On the other end, you have a RESTful architecture. In this case, there is no View. The Controller only sends back the model (or resource representation, in more RESTful terms). The client can be a JavaScript application, a Java server application, any application in which we expose our REST API to. With this architecture, the client decides what to do with this model. Take for instance Twitter. Twitter as the Web (REST) API, that allows our applications to use its API to get such things as status updates, so that we can use it to put that data in our application. That data will come in some format like JSON.

That being said, when working with Spring MVC, it was first built to handle the basic web application architecture. There are may different method signature flavors that allow a view to be produced from our methods. The method could return a ModelAndView where we explicitly create it, or there are implicit ways where we can return some arbitrary object that gets set into model attributes. But either way, somewhere along the request-response cycle, there will be a view produced.

But when we use @ResponseBody, we are saying that we do not want a view produced. We just want to send the return object as the body, in whatever format we specify. We wouldn't want it to be a serialized Java object (though possible). So yes, it needs to be converted to some other common type (this type is normally dealt with through content negotiation - see link below). Honestly, I don't work much with Spring, though I dabble with it here and there. Normally, I use

@RequestMapping(..., produces = MediaType.APPLICATION_JSON_VALUE)

to set the content type, but maybe JSON is the default. Don't quote me, but if you are getting JSON, and you haven't specified the produces, then maybe it is the default. JSON is not the only format. For instance, the above could easily be sent in XML, but you would need to have the produces to MediaType.APPLICATION_XML_VALUE and I believe you need to configure the HttpMessageConverter for JAXB. As for the JSON MappingJacksonHttpMessageConverter configured, when we have Jackson on the classpath.

I would take some time to learn about Content Negotiation. It's a very important part of REST. It'll help you learn about the different response formats and how to map them to your methods.

javascript set cookie with expire time

document.cookie = "cookie_name=cookie_value; max-age=31536000; path=/";

Will set the value for a year.

MySQL Calculate Percentage

try this

   SELECT group_name, employees, surveys, COUNT( surveys ) AS test1, 
        concat(round(( surveys/employees * 100 ),2),'%') AS percentage
    FROM a_test
    GROUP BY employees

DEMO HERE

Making the iPhone vibrate

And if you're using Xamarin (monotouch) framework, simply call

SystemSound.Vibrate.PlayAlertSound()

how to clear the screen in python

If you mean the screen where you have that interpreter prompt >>> you can do CTRL+L on Bash shell can help. Windows does not have equivalent. You can do

import os
os.system('cls')  # on windows

os.system('clear')  # on linux / os x

Python None comparison: should I use "is" or ==?

PEP 8 defines that it is better to use the is operator when comparing singletons.

beyond top level package error in relative import

if you have an __init__.py in an upper folder, you can initialize the import as import file/path as alias in that init file. Then you can use it on lower scripts as:

import alias

Set width to match constraints in ConstraintLayout

From the official doc:

Important: MATCH_PARENT is not recommended for widgets contained in a ConstraintLayout. Similar behavior can be defined by using MATCH_CONSTRAINT with the corresponding left/right or top/bottom constraints being set to "parent".

So if you want achieve MATCH_PARENT effect, you can do this:

<TextView
    android:id="@+id/textView"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:text="TextView"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent" />

Why is init() always called after new()?

The __init__ is called after __new__ so that when you override it in a subclass, your added code will still get called.

If you are trying to subclass a class that already has a __new__, someone unaware of this might start by adapting the __init__ and forwarding the call down to the subclass __init__. This convention of calling __init__ after __new__ helps that work as expected.

The __init__ still needs to allow for any parameters the superclass __new__ needed, but failing to do so will usually create a clear runtime error. And the __new__ should probably explicitly allow for *args and '**kw', to make it clear that extension is OK.

It is generally bad form to have both __new__ and __init__ in the same class at the same level of inheritance, because of the behavior the original poster described.

Disable submit button ONLY after submit

This solution has the advantages of working on mobile and being quite simple:

<form ... onsubmit="myButtonValue.disabled = true; return true;">

psql: FATAL: role "postgres" does not exist

On Ubuntu system, I purged the PostgreSQL and re-installed it. All the databases are restored. This solved the problem for me.

Advice - Take the backup of the databases to be on the safer side.

CSS: fixed to bottom and centered

You should use a sticky footer solution such as this one :

* {
    margin: 0;
}
html, body {
    height: 100%;
}
.wrapper {
    min-height: 100%;
    height: auto !important;
    height: 100%;
    margin: 0 auto -142px; /* the bottom margin is the negative value of the footer's height */
}
.footer, .push {
    height: 142px; /* .push must be the same height as .footer */
}

There are others like this;

* {margin:0;padding:0;} 

/* must declare 0 margins on everything, also for main layout components use padding, not 
vertical margins (top and bottom) to add spacing, else those margins get added to total height 
and your footer gets pushed down a bit more, creating vertical scroll bars in the browser */

html, body, #wrap {height: 100%;}

body > #wrap {height: auto; min-height: 100%;}

#main {padding-bottom: 150px;}  /* must be same height as the footer */

#footer {position: relative;
    margin-top: -150px; /* negative value of footer height */
    height: 150px;
    clear:both;} 

/* CLEAR FIX*/
.clearfix:after {content: ".";
    display: block;
    height: 0;
    clear: both;
    visibility: hidden;}
.clearfix {display: inline-block;}
/* Hides from IE-mac \*/
* html .clearfix { height: 1%;}
.clearfix {display: block;}

with the html:

<div id="wrap">

    <div id="main" class="clearfix">

    </div>

</div>

<div id="footer">

</div>

Partly cherry-picking a commit with Git

The core thing you're going to want here is git add -p (-p is a synonym for --patch). This provides an interactive way to check in content, letting you decide whether each hunk should go in, and even letting you manually edit the patch if necessary.

To use it in combination with cherry-pick:

git cherry-pick -n <commit> # get your patch, but don't commit (-n = --no-commit)
git reset                   # unstage the changes from the cherry-picked commit
git add -p                  # make all your choices (add the changes you do want)
git commit                  # make the commit!

(Thanks to Tim Henigan for reminding me that git-cherry-pick has a --no-commit option, and thanks to Felix Rabe for pointing out that you need to reset! If you only want to leave a few things out of the commit, you could use git reset <path>... to unstage just those files.)

You can of course provide specific paths to add -p if necessary. If you're starting with a patch you could replace the cherry-pick with apply.

If you really want a git cherry-pick -p <commit> (that option does not exist), your can use

git checkout -p <commit>

That will diff the current commit against the commit you specify, and allow you to apply hunks from that diff individually. This option may be more useful if the commit you're pulling in has merge conflicts in part of the commit you're not interested in. (Note, however, that checkout differs from cherry-pick: checkout tries to apply <commit>'s contents entirely, cherry-pick applies the diff of the specified commit from it's parent. This means that checkout can apply more than just that commit, which might be more than you want.)

How to use confirm using sweet alert?

inside your save button click add this code :

$("#btnSave").click(function (e) {
  e.preventDefault();
  swal("Are you sure?", {
    buttons: {
      yes: {
        text: "Yes",
        value: "yes"
      },
      no: {
        text: "No",
        value: "no"
      }
    }
  }).then((value) => {
    if (value === "yes") {
      // Add Your Custom Code for CRUD
    }
    return false;
  });
});

Undefined behavior and sequence points

This is a follow up to my previous answer and contains C++11 related material..

Pre-requisites : An elementary knowledge of Relations (Mathematics).

Is it true that there are no Sequence Points in C++11?

Yes! This is very true.

Sequence Points have been replaced by Sequenced Before and Sequenced After (and Unsequenced and Indeterminately Sequenced) relations in C++11.

What exactly is this 'Sequenced before' thing?

Sequenced Before^(§1.9/13) is a relation which is:

between evaluations executed by a single thread and induces a strict partial order¹

Formally it means given any two evaluations^{(See below)} A and B, if A is sequenced before B, then the execution of A shall precede the execution of B. If A is not sequenced before B and B is not sequenced before A, then A and B are unsequenced ².

Evaluations A and B are indeterminately sequenced when either A is sequenced before B or B is sequenced before A, but it is unspecified which³.

_[NOTES] _{1 : A strict partial order is a binary relation "<" over a set P which is asymmetric, and transitive, i.e., for all a, b, and c in P, we have that:} _{........(i). if a < b then ¬ (b < a) (asymmetry);

........(ii). if a < b and b < c then a < c (transitivity).

2 : The execution of unsequenced evaluations can overlap.

3 : Indeterminately sequenced evaluations cannot overlap, but either could be executed first.}

What is the meaning of the word 'evaluation' in context of C++11?

In C++11, evaluation of an expression (or a sub-expression) in general includes:

value computations (including determining the identity of an object for glvalue evaluation and fetching a value previously assigned to an object for prvalue evaluation) and
initiation of side effects.

Now (§1.9/14) says:

Every value computation and side effect associated with a full-expression is sequenced before every value computation and side effect associated with the next full-expression to be evaluated.

Trivial example:

int x; x = 10; ++x;

Value computation and side effect associated with ++x is sequenced after the value computation and side effect of x = 10;

So there must be some relation between Undefined Behaviour and the above-mentioned things, right?

Yes! Right.

In (§1.9/15) it has been mentioned that

Except where noted, evaluations of operands of individual operators and of subexpressions of individual expressions are unsequenced⁴.

For example :

int main()
{
     int num = 19 ;
     num = (num << 3) + (num >> 3);
}

Evaluation of operands of + operator are unsequenced relative to each other.
Evaluation of operands of << and >> operators are unsequenced relative to each other.

_{4: In an expression that is evaluated more than once during the execution
of a program, unsequenced and indeterminately sequenced evaluations of its subexpressions need not be performed consistently in different evaluations.}

(§1.9/15) The value computations of the operands of an operator are sequenced before the value computation of the result of the operator.

That means in x + y the value computation of x and y are sequenced before the value computation of (x + y).

More importantly

(§1.9/15) If a side effect on a scalar object is unsequenced relative to either

(a) another side effect on the same scalar object

or

(b) a value computation using the value of the same scalar object.

the behaviour is undefined.

Examples:

int i = 5, v[10] = { };
void  f(int,  int);

i = i++ * ++i; // Undefined Behaviour
i = ++i + i++; // Undefined Behaviour
i = ++i + ++i; // Undefined Behaviour
i = v[i++]; // Undefined Behaviour
i = v[++i]: // Well-defined Behavior
i = i++ + 1; // Undefined Behaviour
i = ++i + 1; // Well-defined Behaviour
++++i; // Well-defined Behaviour
f(i = -1, i = -1); // Undefined Behaviour (see below)

When calling a function (whether or not the function is inline), every value computation and side effect associated with any argument expression, or with the postfix expression designating the called function, is sequenced before execution of every expression or statement in the body of the called function. [Note: Value computations and side effects associated with different argument expressions are unsequenced. — end note]

Expressions (5), (7) and (8) do not invoke undefined behaviour. Check out the following answers for a more detailed explanation.

Final Note :

If you find any flaw in the post please leave a comment. Power-users (With rep >20000) please do not hesitate to edit the post for correcting typos and other mistakes.

Paging with Oracle

Just want to summarize the answers and comments. There are a number of ways doing a pagination.

Prior to oracle 12c there were no OFFSET/FETCH functionality, so take a look at whitepaper as the @jasonk suggested. It's the most complete article I found about different methods with detailed explanation of advantages and disadvantages. It would take a significant amount of time to copy-paste them here, so I won't do it.

There is also a good article from jooq creators explaining some common caveats with oracle and other databases pagination. jooq's blogpost

Good news, since oracle 12c we have a new OFFSET/FETCH functionality. OracleMagazine 12c new features. Please refer to "Top-N Queries and Pagination"

You may check your oracle version by issuing the following statement

SELECT * FROM V$VERSION

How do I kill this tomcat process in Terminal?

This worked for me:

Step 1 : echo ps aux | grep org.apache.catalina.startup.Bootstrap | grep -v grep | awk '{ print $2 }'

This above command return "process_id"

Step 2: kill -9 process_id
// This process_id same as Step 1: output

SQL Server String or binary data would be truncated

Please try the following code:

CREATE TABLE [dbo].[Department](
    [Department_name] char(10) NULL
)

INSERT INTO [dbo].[Department]([Department_name]) VALUES  ('Family Medicine')
--error will occur

 ALTER TABLE [Department] ALTER COLUMN [Department_name] char(50)

INSERT INTO [dbo].[Department]([Department_name]) VALUES  ('Family Medicine')

select * from [Department]

Positioning <div> element at center of screen

Use flex. Much simpler and will work regardless of your div size:

_x000D_

.center-screen {_x000D_
  display: flex;_x000D_
  flex-direction: column;_x000D_
  justify-content: center;_x000D_
  align-items: center;_x000D_
  text-align: center;_x000D_
  min-height: 100vh;_x000D_
}

_x000D_

 <html>_x000D_
 <head>_x000D_
 </head>_x000D_
 <body>_x000D_
 <div class="center-screen">_x000D_
 I'm in the center_x000D_
 </div>_x000D_
 </body>_x000D_
 </html>

_x000D_

Convert char* to string C++

char *charPtr = "test string";
cout << charPtr << endl;

string str = charPtr;
cout << str << endl;

What exactly is the meaning of an API?

Lets say you are developing a game and you want the game user to login their facebook profile(to get your profile information) before playing it,so how your game is going to access facebook? Now here comes the API.Facebook has already written the program(API) for you to do it, you have to just use those programs in your game application.using Facebook-API you can use their services in your application.Here is a good and detailed look on API... http://money.howstuffworks.com/business-communications/how-to-leverage-an-api-for-conferencing1.htm

Convert Select Columns in Pandas Dataframe to Numpy Array

The best way for converting to Numpy Array is using '.to_numpy(self, dtype=None, copy=False)'. It is new in version 0.24.0.Refrence

You can also use '.array'.Refrence

Pandas .as_matrix deprecated since version 0.23.0.

C++ - Assigning null to a std::string

I can't assign a null to a String?

No. std::string is not a pointer type; it cannot be made "null." It cannot represent the absence of a value, which is what a null pointer is used to represent.

It can be made empty, by assigning an empty string to it (s = "" or s = std::string()) or by clearing it (s.clear()).

Server.MapPath("."), Server.MapPath("~"), Server.MapPath(@"\"), Server.MapPath("/"). What is the difference?

Server.MapPath specifies the relative or virtual path to map to a physical directory.

Server.MapPath(".")¹ returns the current physical directory of the file (e.g. aspx) being executed
Server.MapPath("..") returns the parent directory
Server.MapPath("~") returns the physical path to the root of the application
Server.MapPath("/") returns the physical path to the root of the domain name (is not necessarily the same as the root of the application)

An example:

Let's say you pointed a web site application (http://www.example.com/) to

C:\Inetpub\wwwroot

and installed your shop application (sub web as virtual directory in IIS, marked as application) in

D:\WebApps\shop

For example, if you call Server.MapPath() in following request:

http://www.example.com/shop/products/GetProduct.aspx?id=2342

then:

Server.MapPath(".")¹ returns D:\WebApps\shop\products
Server.MapPath("..") returns D:\WebApps\shop
Server.MapPath("~") returns D:\WebApps\shop
Server.MapPath("/") returns C:\Inetpub\wwwroot
Server.MapPath("/shop") returns D:\WebApps\shop

If Path starts with either a forward slash (/) or backward slash (\), the MapPath() returns a path as if Path was a full, virtual path.

If Path doesn't start with a slash, the MapPath() returns a path relative to the directory of the request being processed.

Note: in C#, @ is the verbatim literal string operator meaning that the string should be used "as is" and not be processed for escape sequences.

Footnotes

Server.MapPath(null) and Server.MapPath("") will produce this effect too.

C# getting its own class name

Use this

Let say Application Test.exe is running and function is foo() in form1 [basically it is class form1], then above code will generate below response.

string s1 = System.Reflection.MethodBase.GetCurrentMethod().DeclaringType.Name;

This will return .

s1 = "TEST.form1"

for function name:

string s1 = System.Reflection.MethodBase.GetCurrentMethod().Name;

will return

s1 = foo

Note if you want to use this in exception use :

catch (Exception ex)
{

    MessageBox.Show(ex.StackTrace );

}

How do I address unchecked cast warnings?

If I have to use an API that doesn't support Generics.. I try and isolate those calls in wrapper routines with as few lines as possible. I then use the SuppressWarnings annotation and also add the type-safety casts at the same time.

This is just a personal preference to keep things as neat as possible.

Rolling back local and remote git repository by 1 commit

The way to reset the head and do the revert to the previous commit is through

$ git reset HEAD^ --hard
$ git push <branchname> -f

But sometimes it might not be accepted in the remote branch:

To ssh:<git repo>
 ! [rejected]        develop -> develop (non-fast-forward)
error: failed to push some refs to 'ssh:<git repo>'
hint: Updates were rejected because the tip of your current branch is behind
hint: its remote counterpart. Integrate the remote changes (e.g.
hint: 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

then the other way to do is

git revert HEAD
git push <remote branch>

This works fine.

NOTE: remember if the git push -f <force> failed and then you try to revert. Do a git pull before, so that remote and local are in sync and then try git revert.
Check with git log to make sure the remote and local are at same point of commit with same SHA1..

git revert 
A --> B --> C -->D
A--> B --> C --> D --> ^D(taking out the changes and committing reverted diffs)

Getting execute permission to xp_cmdshell

To expand on what has been provided for automatically exporting data as csv to a network share via SQL Server Agent.

(1) Enable the xp_cmdshell procedure:

-- To allow advanced options to be changed.
EXEC sp_configure 'show advanced options', 1
RECONFIGURE
GO

-- Enable the xp_cmdshell procedure
EXEC sp_configure 'xp_cmdshell', 1
RECONFIGURE
GO

(2) Create a login 'Domain\TestUser' (windows user) for the non-sysadmin user that has public access to the master database. Done through user mapping

(3) Give log on as batch job: Navigate to Local Security Policy -> Local Policies -> User Rights Assignment. Add user to "Log on as a batch job"

(4) Give read/write permissions to network folder for domain\user

(5) Grant EXEC permission on the xp_cmdshell stored procedure:

GRANT EXECUTE ON xp_cmdshell TO [Domain\TestUser]

(6) Create a proxy account that xp_cmdshell will be run under using sp_xp_cmdshell_proxy_account

EXEC sp_xp_cmdshell_proxy_account 'Domain\TestUser', 'password_for_domain_user'

(7) If the sp_xp_cmdshell_proxy_account command doesn't work, manually create it

create credential ##xp_cmdshell_proxy_account## with identity = 'Domain\DomainUser', secret = 'password'

(8) Enable SQL Server Agent. Open SQL Server Configuration Manager, navigate to SQL Server Services, enable SQL Server Agent.

(9) Create automated job. Open SSMS, select SQL Server Agent, then right-click jobs and click "New Job".

(10) Select "Owner" as your created user. Select "Steps", make "type" = T-SQL. Fill out command field similar to below. Set delimiter as ','

EXEC master..xp_cmdshell 'SQLCMD -q "select * from master" -o file.csv -s ","

(11) Fill out schedules accordingly.

Java string split with "." (dot)

The dot "." is a special character in java regex engine, so you have to use "\\." to escape this character:

final String extensionRemoved = filename.split("\\.")[0];

I hope this helps

Removing an element from an Array (Java)

Swap the item to be removed with the last item, if resizing the array down is not an interest.

Mockito matcher and array of primitives

I used Matchers.refEq for this.

How do I get a file name from a full path with PHP?

I've done this using the function PATHINFO which creates an array with the parts of the path for you to use! For example, you can do this:

<?php
    $xmlFile = pathinfo('/usr/admin/config/test.xml');

    function filePathParts($arg1) {
        echo $arg1['dirname'], "\n";
        echo $arg1['basename'], "\n";
        echo $arg1['extension'], "\n";
        echo $arg1['filename'], "\n";
    }

    filePathParts($xmlFile);
?>

This will return:

/usr/admin/config
test.xml
xml
test

The use of this function has been available since PHP 5.2.0!

Then you can manipulate all the parts as you need. For example, to use the full path, you can do this:

$fullPath = $xmlFile['dirname'] . '/' . $xmlFile['basename'];

Unable to read data from the transport connection : An existing connection was forcibly closed by the remote host

Another option would be to check the error code generated using try-catch block and first catching a WebException.

In my case, the error code was "SendFailure" because of certificate issue on HTTPS url, once I hit HTTP, that got resolved.

https://docs.microsoft.com/en-us/dotnet/api/system.net.webexceptionstatus?redirectedfrom=MSDN&view=netframework-4.8

How to find the index of an element in an array in Java?

I believe the ~~only~~ sanest way to do this is to manually iterate through the array.

for (int i = 0; i < list.length; i++) {
  if (list[i] == 'e') {
    System.out.println(i);
    break;
  }
}

What is the cleanest way to get the progress of JQuery ajax request?

jQuery has already implemented promises, so it's better to use this technology and not move events logic to options parameter. I made a jQuery plugin that adds progress promise and now it's easy to use just as other promises:

$.ajax(url)
  .progress(function(){
    /* do some actions */
  })
  .progressUpload(function(){
    /* do something on uploading */
  });

Check it out at github

What is the difference between Hibernate and Spring Data JPA

Spring Data is a convenience library on top of JPA that abstracts away many things and brings Spring magic (like it or not) to the persistence store access. It is primarily used for working with relational databases. In short, it allows you to declare interfaces that have methods like findByNameOrderByAge(String name); that will be parsed in runtime and converted into appropriate JPA queries.

Its placement atop of JPA makes its use tempting for:

Rookie developers who don't know SQL or know it badly. This is a recipe for disaster but they can get away with it if the project is trivial.
Experienced engineers who know what they do and want to spindle up things fast. This might be a viable strategy (but read further).

From my experience with Spring Data, its magic is too much (this is applicable to Spring in general). I started to use it heavily in one project and eventually hit several corner cases where I couldn't get the library out of my way and ended up with ugly workarounds. Later I read other users' complaints and realized that these issues are typical for Spring Data. For example, check this issue that led to hours of investigation/swearing:

 public TourAccommodationRate createTourAccommodationRate(
        @RequestBody TourAccommodationRate tourAccommodationRate
    ) {
        if (tourAccommodationRate.getId() != null) {
            throw new BadRequestException("id MUST NOT be specified in a body during entry creation");
        }

        // This is an ugly hack required for the Room slim model to work. The problem stems from the fact that
        // when we send a child entity having the many-to-many (M:N) relation to the containing entity, its
        // information is not fetched. As a result, we get NPEs when trying to access all but its Id in the
        // code creating the corresponding slim model. By detaching the entity from the persistence context we
        // force the ORM to re-fetch it from the database instead of taking it from the cache

        tourAccommodationRateRepository.save(tourAccommodationRate);
        entityManager.detach(tourAccommodationRate);
        return tourAccommodationRateRepository.findOne(tourAccommodationRate.getId());
    }

I ended up going lower level and started using JDBI - a nice library with just enough "magic" to save you from the boilerplate. With it, you have complete control over SQL queries and almost never have to fight the library.

What is the proper REST response code for a valid request but an empty data?

In this scenario Ruby on Rails responses with 404 Not Found.

404 Not Found is more appropriate.

Bootstrap: Open Another Modal in Modal

To open another modal window in a current opened modal window,
you can use bootstrap-modal

bootstrap-modal DEMO

How to make a node.js application run permanently?

During development, I recommend using nodemon. It will restart your server whenever a file changes. As others have pointed out, Forever is an option but in production, it all depends on the platform you are using. You will typically want to use the operating system's recommended way of keeping services up (e.g. http://www.freedesktop.org/wiki/Software/systemd/).

Socket accept - "Too many open files"

I had this problem too. You have a file handle leak. You can debug this by printing out a list of all the open file handles (on POSIX systems):

void showFDInfo()
{
   s32 numHandles = getdtablesize();

   for ( s32 i = 0; i < numHandles; i++ )
   {
      s32 fd_flags = fcntl( i, F_GETFD ); 
      if ( fd_flags == -1 ) continue;


      showFDInfo( i );
   }
}

void showFDInfo( s32 fd )
{
   char buf[256];

   s32 fd_flags = fcntl( fd, F_GETFD ); 
   if ( fd_flags == -1 ) return;

   s32 fl_flags = fcntl( fd, F_GETFL ); 
   if ( fl_flags == -1 ) return;

   char path[256];
   sprintf( path, "/proc/self/fd/%d", fd );

   memset( &buf[0], 0, 256 );
   ssize_t s = readlink( path, &buf[0], 256 );
   if ( s == -1 )
   {
        cerr << " (" << path << "): " << "not available";
        return;
   }
   cerr << fd << " (" << buf << "): ";

   if ( fd_flags & FD_CLOEXEC )  cerr << "cloexec ";

   // file status
   if ( fl_flags & O_APPEND   )  cerr << "append ";
   if ( fl_flags & O_NONBLOCK )  cerr << "nonblock ";

   // acc mode
   if ( fl_flags & O_RDONLY   )  cerr << "read-only ";
   if ( fl_flags & O_RDWR     )  cerr << "read-write ";
   if ( fl_flags & O_WRONLY   )  cerr << "write-only ";

   if ( fl_flags & O_DSYNC    )  cerr << "dsync ";
   if ( fl_flags & O_RSYNC    )  cerr << "rsync ";
   if ( fl_flags & O_SYNC     )  cerr << "sync ";

   struct flock fl;
   fl.l_type = F_WRLCK;
   fl.l_whence = 0;
   fl.l_start = 0;
   fl.l_len = 0;
   fcntl( fd, F_GETLK, &fl );
   if ( fl.l_type != F_UNLCK )
   {
      if ( fl.l_type == F_WRLCK )
         cerr << "write-locked";
      else
         cerr << "read-locked";
      cerr << "(pid:" << fl.l_pid << ") ";
   }
}

By dumping out all the open files you will quickly figure out where your file handle leak is.

If your server spawns subprocesses. E.g. if this is a 'fork' style server, or if you are spawning other processes ( e.g. via cgi ), you have to make sure to create your file handles with "cloexec" - both for real files and also sockets.

Without cloexec, every time you fork or spawn, all open file handles are cloned in the child process.

It is also really easy to fail to close network sockets - e.g. just abandoning them when the remote party disconnects. This will leak handles like crazy.

Return single column from a multi-dimensional array

Quite simple:

$input = array(
  array(
    'tag_name' => 'google'
  ),
  array(
    'tag_name' => 'technology'
  )
);

echo implode(', ', array_map(function ($entry) {
  return $entry['tag_name'];
}, $input));

http://3v4l.org/ltBZ0

and new in php v5.5.0, array_column:

echo implode(', ', array_column($input, 'tag_name'));

Calling a Javascript Function from Console

An example of where the console will return ReferenceError is putting a function inside a JQuery document ready function

//this will fail
$(document).ready(function () {
          myFunction(alert('doing something!'));
          //other stuff
}

To succeed move the function outside the document ready function

//this will work
myFunction(alert('doing something!'));
$(document).ready(function () {

          //other stuff
}

Then in the console window, type the function name with the '()' to execute the function

myFunction()

Also of use is being able to print out the function body to remind yourself what the function does. Do this by leaving off the '()' from the function name

function myFunction(alert('doing something!'))

Of course if you need the function to be registered after the document is loaded then you couldn't do this. But you might be able to work around that.

Which HTTP methods match up to which CRUD methods?

The whole key is whether you're doing an idempotent change or not. That is, if taking action on the message twice will result in “the same” thing being there as if it was only done once, you've got an idempotent change and it should be mapped to PUT. If not, it maps to POST. If you never permit the client to synthesize URLs, PUT is pretty close to Update and POST can handle Create just fine, but that's most certainly not the only way to do it; if the client knows that it wants to create /foo/abc and knows what content to put there, it works just fine as a PUT.

The canonical description of a POST is when you're committing to purchasing something: that's an action which nobody wants to repeat without knowing it. By contrast, setting the dispatch address for the order beforehand can be done with PUT just fine: it doesn't matter if you are told to send to 6 Anywhere Dr, Nowhereville once, twice or a hundred times: it's still the same address. Does that mean that it's an update? Could be… It all depends on how you want to write the back-end. (Note that the results might not be identical: you could report back to the user when they last did a PUT as part of the representation of the resource, which would ensure that repeated PUTs do not cause an identical result, but the result would still be “the same” in a functional sense.)

pandas: multiple conditions while indexing data frame - unexpected behavior

As you can see, the AND operator drops every row in which at least one value equals -1. On the other hand, the OR operator requires both values to be equal to -1 to drop them.

That's right. Remember that you're writing the condition in terms of what you want to keep, not in terms of what you want to drop. For df1:

df1 = df[(df.a != -1) & (df.b != -1)]

You're saying "keep the rows in which df.a isn't -1 and df.b isn't -1", which is the same as dropping every row in which at least one value is -1.

For df2:

df2 = df[(df.a != -1) | (df.b != -1)]

You're saying "keep the rows in which either df.a or df.b is not -1", which is the same as dropping rows where both values are -1.

PS: chained access like df['a'][1] = -1 can get you into trouble. It's better to get into the habit of using .loc and .iloc.

Where are the recorded macros stored in Notepad++?

Notepad++ will forget your macros unless you map them to hotkeys via Settings - Shortcut mapper - Macros before exiting Notepad++ (as per https://superuser.com/questions/332481/how-can-i-add-a-macro-in-notepad. Tested with Notepad v6.8.3 on Windows7.)

Color theme for VS Code integrated terminal

In case you are color picky, use this code to customize every segment.

Step 1: Windows: Open user settings (ctrl + ,) Mac: Command + Shift + P

Step 2: Search for "workbench: color customizations" and select Edit in settings.json. Page the following code inside existing {} and customize as you like.

"workbench.colorCustomizations": {
    "terminal.background":"#131212",
    "terminal.foreground":"#dddad6",
    "terminal.ansiBlack":"#1D2021",
    "terminal.ansiBrightBlack":"#665C54",
    "terminal.ansiBrightBlue":"#0D6678",
    "terminal.ansiBrightCyan":"#8BA59B",
    "terminal.ansiBrightGreen":"#237e02",
    "terminal.ansiBrightMagenta":"#8F4673",
    "terminal.ansiBrightRed":"#FB543F",
    "terminal.ansiBrightWhite":"#FDF4C1",
    "terminal.ansiBrightYellow":"#FAC03B",
    "terminal.ansiCyan":"#8BA59B",
    "terminal.ansiGreen":"#95C085",
    "terminal.ansiMagenta":"#8F4673",
    "terminal.ansiRed":"#FB543F",
    "terminal.ansiWhite":"#A89984",
    "terminal.ansiYellow":"#FAC03B"
  }

Remove Object from Array using JavaScript

The clean solution would be to use Array.filter:

var filtered = someArray.filter(function(el) { return el.Name != "Kristian"; });

The problem with this is that it does not work on IE < 9. However, you can include code from a Javascript library (e.g. underscore.js) that implements this for any browser.

How to convert Varchar to Double in sql?

This might be more desirable, that is use float instead

SELECT fullName, CAST(totalBal as float) totalBal FROM client_info ORDER BY totalBal DESC

Django 1.7 throws django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet

The issue is in your registration app. It seems django-registration calls get_user_module() in models.py at a module level (when models are still being loaded by the application registration process). This will no longer work:

try:
    from django.contrib.auth import get_user_model
    User = get_user_model()
except ImportError:
    from django.contrib.auth.models import User

I'd change this models file to only call get_user_model() inside methods (and not at module level) and in FKs use something like:

user = ForeignKey(settings.AUTH_USER_MODEL)

BTW, the call to django.setup() shouldn't be required in your manage.py file, it's called for you in execute_from_command_line. (source)

correct way to define class variables in Python

Neither way is necessarily correct or incorrect, they are just two different kinds of class elements:

Elements outside the __init__ method are static elements; they belong to the class.
Elements inside the __init__ method are elements of the object (self); they don't belong to the class.

You'll see it more clearly with some code:

class MyClass:
    static_elem = 123

    def __init__(self):
        self.object_elem = 456

c1 = MyClass()
c2 = MyClass()

# Initial values of both elements
>>> print c1.static_elem, c1.object_elem 
123 456
>>> print c2.static_elem, c2.object_elem
123 456

# Nothing new so far ...

# Let's try changing the static element
MyClass.static_elem = 999

>>> print c1.static_elem, c1.object_elem
999 456
>>> print c2.static_elem, c2.object_elem
999 456

# Now, let's try changing the object element
c1.object_elem = 888

>>> print c1.static_elem, c1.object_elem
999 888
>>> print c2.static_elem, c2.object_elem
999 456

As you can see, when we changed the class element, it changed for both objects. But, when we changed the object element, the other object remained unchanged.

JavaScript Uncaught ReferenceError: jQuery is not defined; Uncaught ReferenceError: $ is not defined

Cause you need to add jQuery library to your file:

jQuery UI is just an addon to jQuery which means that
first you need to include the jQuery library → and then the UI.

<script src="path/to/your/jquery.min.js"></script>
<script src="path/to/your/jquery.ui.min.js"></script>

Simple function to sort an array of objects

You can sort an array ([...]) with the .sort function:

var people = [
    {'name': 'a75', 'item1': false, 'item2': false},
    {'name': 'z32', 'item1': true,  'item2': false},
    {'name': 'e77', 'item1': false, 'item2': false},
];

var sorted = people.sort(function IHaveAName(a, b) { // non-anonymous as you ordered...
    return b.name < a.name ?  1 // if b should come earlier, push a to end
         : b.name > a.name ? -1 // if b should come later, push a to begin
         : 0;                   // a and b are equal
});

Log4j: How to configure simplest possible file logging?

Here's a simple one that I often use:

# Set up logging to include a file record of the output
# Note: the file is always created, even if there is 
# no actual output.
log4j.rootLogger=error, stdout, R

# Log format to standard out
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=   %5p\t[%d] [%t] (%F:%L)\n     \t%m%n\n

# File based log output
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=owls_conditions.log
log4j.appender.R.MaxFileSize=10000KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=   %5p\t[%d] [%t] (%F:%L)\n     \t%m%n\n

The format of the log is as follows:

ERROR   [2009-09-13 09:56:01,760] [main] (RDFDefaultErrorHandler.java:44)
        http://www.xfront.com/owl/ontologies/camera/#(line 1 column 1): Content is not allowed in prolog.

Such a format is defined by the string %5p\t[%d] [%t] (%F:%L)\n \t%m%n\n. You can read the meaning of conversion characters in log4j javadoc for PatternLayout.

Included comments should help in understanding what it does. Further notes:

it logs both to console and to file; in this case the file is named owls_conditions.log: change it according to your needs;
files are rotated when they reach 10000KB, and one back-up file is kept

How to find a text inside SQL Server procedures / triggers?

I use this one for work. leave off the []'s though in the @TEXT field, seems to want to return everything...

SET NOCOUNT ON

DECLARE @TEXT   VARCHAR(250)
DECLARE @SQL    VARCHAR(250)

SELECT  @TEXT='10.10.100.50'

CREATE TABLE #results (db VARCHAR(64), objectname VARCHAR(100),xtype VARCHAR(10), definition TEXT)

SELECT @TEXT as 'Search String'
DECLARE #databases CURSOR FOR SELECT NAME FROM master..sysdatabases where dbid>4
    DECLARE @c_dbname varchar(64)   
    OPEN #databases
    FETCH #databases INTO @c_dbname   
    WHILE @@FETCH_STATUS  -1
    BEGIN
        SELECT @SQL = 'INSERT INTO #results '
        SELECT @SQL = @SQL + 'SELECT ''' + @c_dbname + ''' AS db, o.name,o.xtype,m.definition '   
        SELECT @SQL = @SQL + ' FROM '+@c_dbname+'.sys.sql_modules m '   
        SELECT @SQL = @SQL + ' INNER JOIN '+@c_dbname+'..sysobjects o ON m.object_id=o.id'   
        SELECT @SQL = @SQL + ' WHERE [definition] LIKE ''%'+@TEXT+'%'''   
        EXEC(@SQL)
        FETCH #databases INTO @c_dbname
    END
    CLOSE #databases
DEALLOCATE #databases

SELECT * FROM #results order by db, xtype, objectname
DROP TABLE #results

pip or pip3 to install packages for Python 3?

If you had python 2.x and then installed python3, your pip will be pointing to pip3. you can verify that by typing pip --version which would be the same as pip3 --version.

On your system you have now pip, pip2 and pip3.

If you want you can change pip to point to pip2 instead of pip3.

syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING

Your problem is that you're not closing your HEREDOC correctly. The line containing END; must not contain any whitespace afterwards.

Cannot use string offset as an array in php

Since the release PHP 7.1+, is not more possible to assign a value for an array as follow:

$foo = ""; 
$foo['key'] = $foo2;

because as of PHP 7.1.0, applying the empty index operator on a string throws a fatal error. Formerly, the string was silently converted to an array.

ReferenceError: $ is not defined

Add this script inside head tag:

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>

HTML-parser on Node.js

You can also take a look at x-ray: https://github.com/lapwinglabs/x-ray

Dynamically change bootstrap progress bar value when checkboxes checked

Bootstrap 4 progress bar

<div class="progress">
<div class="progress-bar" role="progressbar" style="" aria-valuenow="" aria-valuemin="0" aria-valuemax="100"></div>
</div>

Javascript

change progress bar on next/previous page actions

var count = Number(document.getElementById('count').innerHTML); //set this on page load in a hidden field after an ajax call
var total = document.getElementById('total').innerHTML; //set this on initial page load
var pcg = Math.floor(count/total*100);        
document.getElementsByClassName('progress-bar').item(0).setAttribute('aria-valuenow',pcg);
document.getElementsByClassName('progress-bar').item(0).setAttribute('style','width:'+Number(pcg)+'%');

How to make a checkbox checked with jQuery?

You don't need to control your checkBoxes with jQuery. You can do it with some simple JavaScript.

This JS snippet should work fine:

document.TheFormHere.test.Value = true;

How exactly does <script defer="defer"> work?

UPDATED: 2/19/2016

Consider this answer outdated. Refer to other answers on this post for information relevant to newer browser version.

Basically, defer tells the browser to wait "until it's ready" before executing the javascript in that script block. Usually this is after the DOM has finished loading and document.readyState == 4

The defer attribute is specific to internet explorer. In Internet Explorer 8, on Windows 7 the result I am seeing in your JS Fiddle test page is, 1 - 2 - 3.

The results may vary from browser to browser.

http://msdn.microsoft.com/en-us/library/ms533719(v=vs.85).aspx

Contrary to popular belief IE follows standards more often than people let on, in actuality the "defer" attribute is defined in the DOM Level 1 spec http://www.w3.org/TR/REC-DOM-Level-1/level-one-html.html

The W3C's definition of defer: http://www.w3.org/TR/REC-html40/interact/scripts.html#adef-defer:

"When set, this boolean attribute provides a hint to the user agent that the script is not going to generate any document content (e.g., no "document.write" in javascript) and thus, the user agent can continue parsing and rendering."

T-SQL: Opposite to string concatenation - how to split string into multiple records

There are a wide varieties of solutions to this problem documented here, including this little gem:

CREATE FUNCTION dbo.Split (@sep char(1), @s varchar(512))
RETURNS table
AS
RETURN (
    WITH Pieces(pn, start, stop) AS (
      SELECT 1, 1, CHARINDEX(@sep, @s)
      UNION ALL
      SELECT pn + 1, stop + 1, CHARINDEX(@sep, @s, stop + 1)
      FROM Pieces
      WHERE stop > 0
    )
    SELECT pn,
      SUBSTRING(@s, start, CASE WHEN stop > 0 THEN stop-start ELSE 512 END) AS s
    FROM Pieces
  )

Problem in running .net framework 4.0 website on iis 7.0

After mapping of Application follow these steps

Open IIS Click on Applications Pools Double click on website Change Manage pipeline mode to "classic" click Ok.

Ow change .Net Framework Version to Lower version

Then click Ok

Load jQuery with Javascript and use jQuery

HTML:

<html>
  <head>

  </head>
  <body>

    <div id='status'>jQuery is not loaded yet.</div>
    <input type='button' value='Click here to load it.' onclick='load()' />

  </body>
</html>

Script:

   <script>

        load = function() {
          load.getScript("jquery-1.7.2.js");
          load.tryReady(0); // We will write this function later. It's responsible for waiting until jQuery loads before using it.
        }

        // dynamically load any javascript file.
        load.getScript = function(filename) {
          var script = document.createElement('script')
          script.setAttribute("type","text/javascript")
          script.setAttribute("src", filename)
          if (typeof script!="undefined")
          document.getElementsByTagName("head")[0].appendChild(script)
        }

        </script>

Android XML Percent Symbol

to escape the percent symbol, you just need %%

for example :

String.format("%1$d%%", 10)

returns "10%"

Repeat command automatically in Linux

watch is good but will clean the screen.

watch -n 1 'ps aux | grep php'

MySQL foreach alternative for procedure

Here's the mysql reference for cursors. So I'm guessing it's something like this:

  DECLARE done INT DEFAULT 0;
  DECLARE products_id INT;
  DECLARE result varchar(4000);
  DECLARE cur1 CURSOR FOR SELECT products_id FROM sets_products WHERE set_id = 1;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

  OPEN cur1;

  REPEAT
    FETCH cur1 INTO products_id;
    IF NOT done THEN
      CALL generate_parameter_list(@product_id, @result);
      SET param = param + "," + result; -- not sure on this syntax
    END IF;
  UNTIL done END REPEAT;

  CLOSE cur1;

  -- now trim off the trailing , if desired

List of ANSI color escape sequences

For these who don't get proper results other than mentioned languages, if you're using C# to print a text into console(terminal) window you should replace "\033" with "\x1b". In Visual Basic it would be Chrw(27).

How do I get length of list of lists in Java?

Just use

int listCount = data.size();

That tells you how many lists there are (assuming none are null). If you want to find out how many strings there are, you'll need to iterate:

int total = 0;
for (List<String> sublist : data) {
    // TODO: Null checking
    total += sublist.size();
}
// total is now the total number of strings

Virtual Serial Port for Linux

Use socat for this:

For example:

socat PTY,link=/dev/ttyS10 PTY,link=/dev/ttyS11

How to find count of Null and Nan values for each column in a PySpark dataframe efficiently?

You can use method shown here and replace isNull with isnan:

from pyspark.sql.functions import isnan, when, count, col

df.select([count(when(isnan(c), c)).alias(c) for c in df.columns]).show()
+-------+----------+---+
|session|timestamp1|id2|
+-------+----------+---+
|      0|         0|  3|
+-------+----------+---+

df.select([count(when(isnan(c) | col(c).isNull(), c)).alias(c) for c in df.columns]).show()
+-------+----------+---+
|session|timestamp1|id2|
+-------+----------+---+
|      0|         0|  5|
+-------+----------+---+

Select all 'tr' except the first one

By adding a class to either the first tr or the subsequent trs. There is no crossbrowser way of selecting the rows you want with CSS alone.

However, if you don't care about Internet Explorer 6, 7 or 8:

tr:not(:first-child) {
    color: red;
}

Creating Dynamic button with click event in JavaScript

<!DOCTYPE html>
<html>
<body>

<p>Click the button to make a BUTTON element with text.</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
    var btn = document.createElement("BUTTON");
    var t = document.createTextNode("CLICK ME");

    btn.setAttribute("style","color:red;font-size:23px");

    btn.appendChild(t);
    document.body.appendChild(btn);

    btn.setAttribute("onclick", alert("clicked"));

}
</script>

</body>
</html>

Is try-catch like error handling possible in ASP Classic?

There are two approaches, you can code in JScript or VBScript which do have the construct or you can fudge it in your code.

Using JScript you'd use the following type of construct:

<script language="jscript" runat="server">
try  {
    tryStatements
}
catch(exception) {
    catchStatements
}
finally {
    finallyStatements
}
</script>

In your ASP code you fudge it by using on error resume next at the point you'd have a try and checking err.Number at the point of a catch like:

<%
' Turn off error Handling
On Error Resume Next


'Code here that you want to catch errors from

' Error Handler
If Err.Number <> 0 Then
   ' Error Occurred - Trap it
   On Error Goto 0 ' Turn error handling back on for errors in your handling block
   ' Code to cope with the error here
End If
On Error Goto 0 ' Reset error handling.

%>

NameError: name 'python' is not defined

When you run the Windows Command Prompt, and type in python, it starts the Python interpreter.

Typing it again tries to interpret python as a variable, which doesn't exist and thus won't work:

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\USER>python
Python 2.7.5 (default, May 15 2013, 22:43:36) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> python
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'python' is not defined
>>> print("interpreter has started")
interpreter has started
>>> quit() # leave the interpreter, and go back to the command line

C:\Users\USER>

If you're not doing this from the command line, and instead running the Python interpreter (python.exe or IDLE's shell) directly, you are not in the Windows Command Line, and python is interpreted as a variable, which you have not defined.

How to show math equations in general github's markdown(not github's blog)

One other work-around is to use jupyter notebooks and use the markdown mode in cells to render equations.

Basic stuff seems to work perfectly, like centered equations

\begin{equation}
...
\end{equation}

or inline equations

$ \sum_{\forall i}{x_i^{2}} $

Although, one of the functions that I really wanted did not render at all in github was \mbox{}, which was a bummer. But, all in all this has been the most successful way of rendering equations on github.

Sharing link on WhatsApp from mobile website (not application) for Android

According to the new documentation, the link is now:

<a href="https://wa.me/?text=urlencodedtext">Share this</a>

If it doesn't work, try this one :

<a href="whatsapp://send?text=urlencodedtext">Share this</a>

How to access nested elements of json object using getJSONArray method

You have to decompose the full object to reach the entry array.

Assuming REPONSE_JSON_OBJECT is already a parsed JSONObject.

REPONSE_JSON_OBJECT.getJSONObject("result")
    .getJSONObject("map")
    .getJSONArray("entry");

Windows service with timer

Here's a working example in which the execution of the service is started in the OnTimedEvent of the Timer which is implemented as delegate in the ServiceBase class and the Timer logic is encapsulated in a method called SetupProcessingTimer():

public partial class MyServiceProject: ServiceBase
{

private Timer _timer;

public MyServiceProject()
{
    InitializeComponent();
}

private void SetupProcessingTimer()
{
    _timer = new Timer();
    _timer.AutoReset = true;
    double interval = Settings.Default.Interval;
    _timer.Interval = interval * 60000;
    _timer.Enabled = true;
    _timer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
}

private void OnTimedEvent(object source, ElapsedEventArgs e)
{
    // begin your service work
    MakeSomething();
}

protected override void OnStart(string[] args)
{
    SetupProcessingTimer();
}

...
}

The Interval is defined in app.config in minutes:

<userSettings>
    <MyProject.Properties.Settings>
        <setting name="Interval" serializeAs="String">
            <value>1</value>
        </setting>
    </MyProject.Properties.Settings>
</userSettings>

Thymeleaf using path variables to th:href

The right way according to Thymeleaf documention for adding parameters is:

<a th:href="@{/category/edit/{id}(id=${category.idCategory})}">view</a>

How to send a “multipart/form-data” POST in Android with Volley

I might be wrong on this but I think you need to implement your own com.android.volley.toolbox.HttpStack for this because the default ones (HurlStack if version > Gingerbread or HttpClientStack) don't deal with multipart/form-data.

Edit:

And indeed I was wrong. I was able to do it using MultipartEntity in Request like this:

public class MultipartRequest extends Request<String> {

    private MultipartEntity entity = new MultipartEntity();

    private static final String FILE_PART_NAME = "file";
    private static final String STRING_PART_NAME = "text";

    private final Response.Listener<String> mListener;
    private final File mFilePart;
    private final String mStringPart;

    public MultipartRequest(String url, Response.ErrorListener errorListener, Response.Listener<String> listener, File file, String stringPart)
    {
        super(Method.POST, url, errorListener);

        mListener = listener;
        mFilePart = file;
        mStringPart = stringPart;
        buildMultipartEntity();
    }

    private void buildMultipartEntity()
    {
        entity.addPart(FILE_PART_NAME, new FileBody(mFilePart));
        try
        {
            entity.addPart(STRING_PART_NAME, new StringBody(mStringPart));
        }
        catch (UnsupportedEncodingException e)
        {
            VolleyLog.e("UnsupportedEncodingException");
        }
    }

    @Override
    public String getBodyContentType()
    {
        return entity.getContentType().getValue();
    }

    @Override
    public byte[] getBody() throws AuthFailureError
    {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try
        {
            entity.writeTo(bos);
        }
        catch (IOException e)
        {
            VolleyLog.e("IOException writing to ByteArrayOutputStream");
        }
        return bos.toByteArray();
    }

    @Override
    protected Response<String> parseNetworkResponse(NetworkResponse response)
    {
        return Response.success("Uploaded", getCacheEntry());
    }

    @Override
    protected void deliverResponse(String response)
    {
        mListener.onResponse(response);
    }
}

It's pretty raw but I tried it with an image and a simple string and it works. The response is a placeholder, doesn't make much sense to return a Response String in this case. I had problems using apache httpmime to use MultipartEntity so I used this https://code.google.com/p/httpclientandroidlib/ don't know if there's a better way. Hope it helps.

Edit

You can use httpmime without using httpclientandroidlib, the only dependency is httpcore.

How to correctly set Http Request Header in Angular 2

Your parameter for the request options in http.put() should actually be of type RequestOptions. Try something like this:

let headers = new Headers();
headers.append('Content-Type', 'application/json');
headers.append('authentication', `${student.token}`);

let options = new RequestOptions({ headers: headers });
return this.http
    .put(url, JSON.stringify(student), options)

Return number of rows affected by UPDATE statements

CREATE PROCEDURE UpdateTables
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;
    DECLARE @RowCount1 INTEGER
    DECLARE @RowCount2 INTEGER
    DECLARE @RowCount3 INTEGER
    DECLARE @RowCount4 INTEGER

    UPDATE Table1 Set Column = 0 WHERE Column IS NULL
    SELECT @RowCount1 = @@ROWCOUNT
    UPDATE Table2 Set Column = 0 WHERE Column IS NULL
    SELECT @RowCount2 = @@ROWCOUNT
    UPDATE Table3 Set Column = 0 WHERE Column IS NULL
    SELECT @RowCount3 = @@ROWCOUNT
    UPDATE Table4 Set Column = 0 WHERE Column IS NULL
    SELECT @RowCount4 = @@ROWCOUNT

    SELECT @RowCount1 AS Table1, @RowCount2 AS Table2, @RowCount3 AS Table3, @RowCount4 AS Table4
END

How to get the separate digits of an int number?

Easier way I think is to convert the number to string and use substring to extract and then convert to integer.

Something like this:

int digits1 =Integer.parseInt( String.valueOf(201432014).substring(0,4));
    System.out.println("digits are: "+digits1);

ouput is 2014

How to convert a string of numbers to an array of numbers?

The underscore js way -

var a = "1,2,3,4",
  b = a.split(',');

//remove falsy/empty values from array after split
b = _.compact(b);
//then Convert array of string values into Integer
b = _.map(b, Number);

console.log('Log String to Int conversion @b =', b);

How to count how many values per level in a given factor?

Here 2 ways to do it:

set.seed(1)
tt <- sample(letters,100,rep=TRUE)

## using table
table(tt)
tt
a b c d e f g h i j k l m n o p q r s t u v w x y z 
2 3 3 3 2 4 6 1 6 5 6 4 7 2 2 2 5 4 5 3 8 4 5 4 3 1 
## using tapply
tapply(tt,tt,length)
a b c d e f g h i j k l m n o p q r s t u v w x y z 
2 3 3 3 2 4 6 1 6 5 6 4 7 2 2 2 5 4 5 3 8 4 5 4 3 1

Animate a custom Dialog

First, you have to create two animation resources in res/anim dir

slide_up.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate
    android:duration="@android:integer/config_mediumAnimTime"
    android:fromYDelta="100%"
    android:interpolator="@android:anim/accelerate_interpolator"
    android:toXDelta="0">
</translate>
</set>

slide_bottom.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate 
    android:duration="@android:integer/config_mediumAnimTime" 
    android:fromYDelta="0%p" 
    android:interpolator="@android:anim/accelerate_interpolator" 
    android:toYDelta="100%p">
</translate>
</set>

then you have to create a style

<style name="DialogAnimation">
    <item name="android:windowEnterAnimation">@anim/slide_up</item>
    <item name="android:windowExitAnimation">@anim/slide_bottom</item>
</style>

and add this line to your class

dialog.getWindow().getAttributes().windowAnimations = R.style.DialogAnimation; //style id

Based in http://www.devexchanges.info/2015/10/showing-dialog-with-animation-in-android.html

AddTransient, AddScoped and AddSingleton Services Differences

TL;DR

Transient objects are always different; a new instance is provided to every controller and every service.

Scoped objects are the same within a request, but different across different requests.

Singleton objects are the same for every object and every request.

For more clarification, this example from .NET documentation shows the difference:

To demonstrate the difference between these lifetime and registration options, consider a simple interface that represents one or more tasks as an operation with a unique identifier, OperationId. Depending on how we configure the lifetime for this service, the container will provide either the same or different instances of the service to the requesting class. To make it clear which lifetime is being requested, we will create one type per lifetime option:

using System;

namespace DependencyInjectionSample.Interfaces
{
    public interface IOperation
    {
        Guid OperationId { get; }
    }

    public interface IOperationTransient : IOperation
    {
    }

    public interface IOperationScoped : IOperation
    {
    }

    public interface IOperationSingleton : IOperation
    {
    }

    public interface IOperationSingletonInstance : IOperation
    {
    }
}

We implement these interfaces using a single class, Operation, that accepts a GUID in its constructor, or uses a new GUID if none is provided:

using System;
using DependencyInjectionSample.Interfaces;
namespace DependencyInjectionSample.Classes
{
    public class Operation : IOperationTransient, IOperationScoped, IOperationSingleton, IOperationSingletonInstance
    {
        Guid _guid;
        public Operation() : this(Guid.NewGuid())
        {

        }

        public Operation(Guid guid)
        {
            _guid = guid;
        }

        public Guid OperationId => _guid;
    }
}

Next, in ConfigureServices, each type is added to the container according to its named lifetime:

services.AddTransient<IOperationTransient, Operation>();
services.AddScoped<IOperationScoped, Operation>();
services.AddSingleton<IOperationSingleton, Operation>();
services.AddSingleton<IOperationSingletonInstance>(new Operation(Guid.Empty));
services.AddTransient<OperationService, OperationService>();

Note that the IOperationSingletonInstance service is using a specific instance with a known ID of Guid.Empty, so it will be clear when this type is in use. We have also registered an OperationService that depends on each of the other Operation types, so that it will be clear within a request whether this service is getting the same instance as the controller, or a new one, for each operation type. All this service does is expose its dependencies as properties, so they can be displayed in the view.

using DependencyInjectionSample.Interfaces;

namespace DependencyInjectionSample.Services
{
    public class OperationService
    {
        public IOperationTransient TransientOperation { get; }
        public IOperationScoped ScopedOperation { get; }
        public IOperationSingleton SingletonOperation { get; }
        public IOperationSingletonInstance SingletonInstanceOperation { get; }

        public OperationService(IOperationTransient transientOperation,
            IOperationScoped scopedOperation,
            IOperationSingleton singletonOperation,
            IOperationSingletonInstance instanceOperation)
        {
            TransientOperation = transientOperation;
            ScopedOperation = scopedOperation;
            SingletonOperation = singletonOperation;
            SingletonInstanceOperation = instanceOperation;
        }
    }
}

To demonstrate the object lifetimes within and between separate individual requests to the application, the sample includes an OperationsController that requests each kind of IOperation type as well as an OperationService. The Index action then displays all of the controller’s and service’s OperationId values.

using DependencyInjectionSample.Interfaces;
using DependencyInjectionSample.Services;
using Microsoft.AspNetCore.Mvc;

namespace DependencyInjectionSample.Controllers
{
    public class OperationsController : Controller
    {
        private readonly OperationService _operationService;
        private readonly IOperationTransient _transientOperation;
        private readonly IOperationScoped _scopedOperation;
        private readonly IOperationSingleton _singletonOperation;
        private readonly IOperationSingletonInstance _singletonInstanceOperation;

        public OperationsController(OperationService operationService,
            IOperationTransient transientOperation,
            IOperationScoped scopedOperation,
            IOperationSingleton singletonOperation,
            IOperationSingletonInstance singletonInstanceOperation)
        {
            _operationService = operationService;
            _transientOperation = transientOperation;
            _scopedOperation = scopedOperation;
            _singletonOperation = singletonOperation;
            _singletonInstanceOperation = singletonInstanceOperation;
        }

        public IActionResult Index()
        {
            // ViewBag contains controller-requested services
            ViewBag.Transient = _transientOperation;
            ViewBag.Scoped = _scopedOperation;
            ViewBag.Singleton = _singletonOperation;
            ViewBag.SingletonInstance = _singletonInstanceOperation;

            // Operation service has its own requested services
            ViewBag.Service = _operationService;
            return View();
        }
    }
}

Now two separate requests are made to this controller action:

Observe which of the OperationId values varies within a request, and between requests.

Transient objects are always different; a new instance is provided to every controller and every service.
Scoped objects are the same within a request, but different across different requests
Singleton objects are the same for every object and every request (regardless of whether an instance is provided in ConfigureServices)

Show an image preview before upload

_x000D_

function handleFileSelect(evt) {_x000D_
    var files = evt.target.files;_x000D_
_x000D_
    // Loop through the FileList and render image files as thumbnails._x000D_
    for (var i = 0, f; f = files[i]; i++) {_x000D_
_x000D_
      // Only process image files._x000D_
      if (!f.type.match('image.*')) {_x000D_
        continue;_x000D_
      }_x000D_
_x000D_
      var reader = new FileReader();_x000D_
_x000D_
      // Closure to capture the file information._x000D_
      reader.onload = (function(theFile) {_x000D_
        return function(e) {_x000D_
          // Render thumbnail._x000D_
          var span = document.createElement('span');_x000D_
          span.innerHTML = _x000D_
          [_x000D_
            '<img style="height: 75px; border: 1px solid #000; margin: 5px" src="', _x000D_
            e.target.result,_x000D_
            '" title="', escape(theFile.name), _x000D_
            '"/>'_x000D_
          ].join('');_x000D_
          _x000D_
          document.getElementById('list').insertBefore(span, null);_x000D_
        };_x000D_
      })(f);_x000D_
_x000D_
      // Read in the image file as a data URL._x000D_
      reader.readAsDataURL(f);_x000D_
    }_x000D_
  }_x000D_
_x000D_
  document.getElementById('files').addEventListener('change', handleFileSelect, false);

_x000D_

<input type="file" id="files" multiple />_x000D_
<output id="list"></output>

_x000D_

Facebook page automatic "like" URL (for QR Code)

The answers above seem partly outdated.

The URL builder on https://developers.facebook.com/docs/plugins/like-button/ worked nicely for me.

You can configure, preview and the get the code/URL in different flavors: HTML5, XFBML, IFRAME, URL

Python: Get HTTP headers from urllib2.urlopen call?

Use the response.info() method to get the headers.

From the urllib2 docs:

urllib2.urlopen(url[, data][, timeout])

...

This function returns a file-like object with two additional methods:

geturl() — return the URL of the resource retrieved, commonly used to determine if a redirect was followed

info() — return the meta-information of the page, such as headers, in the form of an httplib.HTTPMessage instance (see Quick Reference to HTTP Headers)

So, for your example, try stepping through the result of response.info().headers for what you're looking for.

Note the major caveat to using httplib.HTTPMessage is documented in python issue 4773.

on change event for file input element

The OnChange event is a good choice. But if a user select the same image, the event will not be triggered because the current value is the same as the previous.

The image is the same with a width changed, for example, and it should be uploaded to the server.

To prevent this problem you could to use the following code:

$(document).ready(function(){
    $("input[type=file]").click(function(){
        $(this).val("");
    });

    $("input[type=file]").change(function(){
        alert($(this).val());
    });
});

curl Failed to connect to localhost port 80

I also had problem with refused connection on port 80. I didn't use localhost.

curl --data-binary "@/textfile.txt" "http://www.myserver.com/123.php"

Problem was that I had umlauts äåö in my textfile.txt.

ValueError: setting an array element with a sequence

In my case, the problem was with a scatterplot of a dataframe X[]:

ax.scatter(X[:,0],X[:,1],c=colors,    
       cmap=CMAP, edgecolor='k', s=40)  #c=y[:,0],

#ValueError: setting an array element with a sequence.
#Fix with .toarray():
colors = 'br'
y = label_binarize(y, classes=['Irrelevant','Relevant'])
ax.scatter(X[:,0].toarray(),X[:,1].toarray(),c=colors,   
       cmap=CMAP, edgecolor='k', s=40)

How to compare two dates in php

Using DateTime::createFromFormat:

$format = "d_m_y";
$date1  = \DateTime::createFromFormat($format, "03_01_12");
$date2  = \DateTime::createFromFormat($format, "31_12_11");

var_dump($date1 > $date2);

Could not load file or assembly 'log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=692fbea5521e1304'

If you don't see log4net.dll in %systemdrive%\windows\assembly\ on the machine you are attempting to deploy it on, it is likely you haven't successfully installed the redistributable for Crystal Reports for .Net Framework 4.0

Install (or reinstall) the latest service pack from http://scn.sap.com/docs/DOC-7824 (SAP Crystal Reports, developer version for Microsoft Visual Studio Updates & Runtime Downloads)

That runtime distribution should add log4net to the GAC along with a bunch of CrystalDecisions dll's

Set port for php artisan.php serve

Andreas' answer above was helpful in solving my problem of how to test artisan on port 80. Port 80 can be specified like the other port numbers, but regular users do not have permissions to run anything on that port.

Drop a little common sense on there and you end up with this for Linux:

sudo php artisan serve --port=80

This will allow you to test on localhost without specifying the port in your browser. You can also use this to set up a temporary demo, as I have done.

Keep in mind, however, that PHP's built in server is not designed for production. Use nginx/Apache for production.

How to delete from a table where ID is in a list of IDs?

Your question almost spells the SQL for this:

DELETE FROM table WHERE id IN (1, 4, 6, 7)

libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)

For me, the problem was in my IBAction with a UIButton.

When you Ctrl+Drag to create an IBAction from a UIButton, make sure to select "UIButton" from the Type dropdown. The default selection of AnyObject causes the app to crash when you tap on the UIButton.

Error:Cause: unable to find valid certification path to requested target

If you are using kotlin and its showing this error please update your kotlin gradle plugin in project level build.gradle.
The certificate expired case : Go to certificates in settings and check if any certificate is expired if any, delete that certificate and clean and sync it will work.
Dependencies- unable to find case : In this case delete that dependency and sync the project then add the dependency again with some another version(downgraded version) and sync the project it will work.

These three cases i faced and wasted so much time, hope this will help someone and save someones day.

Thankyou - happy coding**:-)**

Unable to send email using Gmail SMTP server through PHPMailer, getting error: SMTP AUTH is required for message submission on port 587. How to fix?

Also worth noting that if you have two factor authentication enabled, you'll need to setup an application specific password to use in place of your email account's password.

You can generate an application specific password by following these instructions: https://support.google.com/accounts/answer/185833

Then set $mail->Password to your application specific password.

Redirect all output to file in Bash

You can use exec command to redirect all stdout/stderr output of any commands later.

sample script:

exec 2> your_file2 > your_file1
your other commands.....

Assert an object is a specific type

Solution for JUnit 5

The documentation says:

However, JUnit Jupiter’s org.junit.jupiter.Assertions class does not provide an assertThat() method like the one found in JUnit 4’s org.junit.Assert class which accepts a Hamcrest Matcher. Instead, developers are encouraged to use the built-in support for matchers provided by third-party assertion libraries.

Example for Hamcrest:

import static org.hamcrest.CoreMatchers.instanceOf;
import static org.hamcrest.MatcherAssert.assertThat;

import org.junit.jupiter.api.Test;

class HamcrestAssertionDemo {

    @Test
    void assertWithHamcrestMatcher() {
        SubClass subClass = new SubClass();
        assertThat(subClass, instanceOf(BaseClass.class));
    }

}

Example for AssertJ:

import static org.assertj.core.api.Assertions.assertThat;

import org.junit.jupiter.api.Test;

class AssertJDemo {

    @Test
    void assertWithAssertJ() {
        SubClass subClass = new SubClass();
        assertThat(subClass).isInstanceOf(BaseClass.class);
    }

}

Note that this assumes you want to test behaviors similar to instanceof (which accepts subclasses). If you want exact equal type, I don’t see a better way than asserting the two class to be equal like you mentioned in the question.

Get the time of a datetime using T-SQL?

Just to add that from SQL Server 2008, there is a TIME datatype so from then on you can do:

SELECT CONVERT(TIME, GETDATE())

Might be useful for those that use SQL 2008+ and find this question.

How to suspend/resume a process in Windows?

I use (a very old) process explorer from SysInternals (procexp.exe). It is a replacement / addition to the standard Task manager, you can suspend a process from there.

Edit: Microsoft has bought over SysInternals, url: procExp.exe

Other than that you can set the process priority to low so that it does not get in the way of other processes, but this will not suspend the process.

Do you need to dispose of objects and set them to null?

You never need to set objects to null in C#. The compiler and runtime will take care of figuring out when they are no longer in scope.

Yes, you should dispose of objects that implement IDisposable.

Running Java Program from Command Line Linux

(This is the KISS answer.)

Let's say you have several .java files in the current directory:

$ ls -1 *.java
javaFileName1.java
javaFileName2.java

Let's say each of them have a main() method (so they are programs, not libs), then to compile them do:

javac *.java -d .

This will generate as many subfolders as "packages" the .java files are associated to. In my case all java files where inside under the same package name packageName, so only one folder was generated with that name, so to execute each of them:

java -cp . packageName.javaFileName1
java -cp . packageName.javaFileName2

Commands out of sync; you can't run this command now

This is not related to the original question, but i had the same error-message and this thread is the first hit in Google and it took me a while to figure out what the Problem was, so it May be of use for others:

i'm NOT using mysqli, still using mysql_connect i had some simple querys, but ONE query caused all other querys to fail within the same Connection.

I use mysql 5.7 and php 5.6 i had a table with the data-Type "JSON". obviously, my php-version did not recognize the return value from mysql (php just did not know what to do with the JSON-Format because the built-in mysql-module was too old (at least i think))

for now i changed the JSON-Field-Type to Text (as for now i don't need the native mysql JSON-functionality) and everything works fine

How do I generate random integers within a specific range in Java?

This is the easy way to do this.

import java.util.Random;
class Example{
    public static void main(String args[]){
        /*-To test-
        for(int i = 1 ;i<20 ; i++){
            System.out.print(randomnumber()+",");
        }
        */

        int randomnumber = randomnumber();

    }

    public static int randomnumber(){
        Random rand = new Random();
        int randomNum = rand.nextInt(6) + 5;

        return randomNum;
    }
}

In there 5 is the starting point of random numbers. 6 is the range including number 5.

How to trigger a click on a link using jQuery

If you are trying to trigger an event on the anchor, then the code you have will work I recreated your example in jsfiddle with an added eventHandler so you can see that it works:

$(document).on("click", "a", function(){
    $(this).text("It works!");
});

$(document).ready(function(){
    $("a").trigger("click");
});

Are you trying to cause the user to navigate to a certain point on the webpage by clicking the anchor, or are you trying to trigger events bound to it? Maybe you haven't actually bound the click event successfully to the event?

Also this:

$('#titleee').find('a').trigger('click');

is the equivalent of this:

$('#titleee a').trigger('click');

No need to call find. :)

Is there a way to do repetitive tasks at intervals?

How about something like

package main

import (
    "fmt"
    "time"
)

func schedule(what func(), delay time.Duration) chan bool {
    stop := make(chan bool)

    go func() {
        for {
            what()
            select {
            case <-time.After(delay):
            case <-stop:
                return
            }
        }
    }()

    return stop
}

func main() {
    ping := func() { fmt.Println("#") }

    stop := schedule(ping, 5*time.Millisecond)
    time.Sleep(25 * time.Millisecond)
    stop <- true
    time.Sleep(25 * time.Millisecond)

    fmt.Println("Done")
}

Playground

Remove multiple objects with rm()

An other solution rm(list=ls(pattern="temp")), remove all objects matching the pattern.

Change background colour for Visual Studio

This is the only one right answer on this whole page as people answered about "Visual Studio", not "Visual Studio Code":

To change color theme in "Visual Studio Code", use:

File -> Preferences -> Color Theme -> select any color theme you like

You can also download other custom themes as extensions. To do that, open extensions tab on sidebar and type "theme" into the search field to filter extensions only to themes related ones. Click any you like, click "download" and then "install". After installation and restarting VSC, you can find newly installed themes next to default themes in the same place:

File -> Preferences -> Color Theme -> select newly downloaded color theme

PS - Microsoft made bad naming decision by calling this new editor Visual Studio Code, it's terrible how many wrong links we have in google and stackoverflow. They should rename it to VSCode or something.

Generate random string/characters in JavaScript

_x000D_

let r = Math.random().toString(36).substring(7);_x000D_
console.log("random", r);

_x000D_

Note: The above algorithm has the following weaknesses:

It will generate anywhere between 0 and 6 characters due to the fact that trailing zeros get removed when stringifying floating points.
It depends deeply on the algorithm used to stringify floating point numbers, which is horrifically complex. (See the paper "How to Print Floating-Point Numbers Accurately".)
Math.random() may produce predictable ("random-looking" but not really random) output depending on the implementation. The resulting string is not suitable when you need to guarantee uniqueness or unpredictability.
Even if it produced 6 uniformly random, unpredictable characters, you can expect to see a duplicate after generating only about 50,000 strings, due to the birthday paradox. (sqrt(36^6) = 46656)

Get current language in CultureInfo

This is what i used:

var culture = System.Globalization.CultureInfo.CurrentCulture;

and it's working :)

Android WebView Cookie Problem

I've spent the greater half of 3 hours working on a very similar issue. In my case I had a number of calls, that I made to a web service using a DefaulHttpClient and then I wanted to set the session and all other corresponding cookies in my WebView.

I don't know if this will solve your problem, since I don't know what your getCookie() method does, but in my case I actually had to call.

cookieManager.removeSessionCookie();

First to remove the session cookie and then re-add it. I was finding that when I tried to set the JSESSIONID cookie without first removing it, the value I wanted to set it to wasn't being save. Not sure if this will help you particular issue, but thought I'd share what I had found.

How do you reverse a string in place in JavaScript?

_x000D_

    function reverse(string)_x000D_
    {_x000D_
    let arr = [];_x000D_
    for(let char of string) {_x000D_
      arr.unshift(char);_x000D_
    }_x000D_
    let rev = arr.join('')_x000D_
    return rev_x000D_
    }_x000D_
    _x000D_
    let result = reverse("hello")_x000D_
    console.log(result)

_x000D_

docker: Error response from daemon: Get https://registry-1.docker.io/v2/: Service Unavailable. IN DOCKER , MAC

I had this issue when I first installed Docker and ran

docker run hello-world

I was on a corporate network and switching to my personal network solved the issue for me.

Find an item in List by LINQ?

If you want the index of the element, this will do it:

int index = list.Select((item, i) => new { Item = item, Index = i })
                .First(x => x.Item == search).Index;

// or
var tagged = list.Select((item, i) => new { Item = item, Index = i });
int index = (from pair in tagged
            where pair.Item == search
            select pair.Index).First();

You can't get rid of the lambda in the first pass.

Note that this will throw if the item doesn't exist. This solves the problem by resorting to nullable ints:

var tagged = list.Select((item, i) => new { Item = item, Index = (int?)i });
int? index = (from pair in tagged
            where pair.Item == search
            select pair.Index).FirstOrDefault();

If you want the item:

// Throws if not found
var item = list.First(item => item == search);
// or
var item = (from item in list
            where item == search
            select item).First();

// Null if not found
var item = list.FirstOrDefault(item => item == search);
// or
var item = (from item in list
            where item == search
            select item).FirstOrDefault();

If you want to count the number of items that match:

int count = list.Count(item => item == search);
// or
int count = (from item in list
            where item == search
            select item).Count();

If you want all the items that match:

var items = list.Where(item => item == search);
// or
var items = from item in list
            where item == search
            select item;

And don't forget to check the list for null in any of these cases.

Or use (list ?? Enumerable.Empty<string>()) instead of list.

Thanks to Pavel for helping out in the comments.

Refresh DataGridView when updating data source

The cleanest, most efficient and paradigm-friendly solution in this case is to use a System.Windows.Forms.BindingSource as a proxy between your list of items (datasource) and your DataGridView:

var itemStates = new List<ItemState>();
var bindingSource1 = new System.Windows.Forms.BindingSource { DataSource = itemStates };
dataGridView1.DataSource = bindingSource1;

Then, when adding items, use Add() method of BindingSource instead of your list's Add() method:

for (var i = 0; i < 10; i++)
{
    bindingSource1.Add(new ItemState { Id = i.ToString() });
    System.Threading.Thread.Sleep(500);
}

This way you adding items to your list and notifying DataGridView about those additions with the same line of code. No need to reset DataGridView's DataSource every time you make a change to the list.

It also worth mentioning that you can drop a BindingSource onto your form directly in Visual Studio's Forms Designer and attach it as a data source to your DataGridView there as well, which saves you a line of code in the above example where I'm doing it manually.

How do I get the information from a meta tag with JavaScript?

This code works for me

<meta name="text" property="text" content="This is text" />
<meta name="video" property="text" content="http://video.com/video33353.mp4" />

var x = document.getElementsByTagName("META");
    var txt = "";
    var i;
    for (i = 0; i < x.length; i++) {
        if (x[i].name=="video")
        {
             alert(x[i].content);
         }

    }

Example fiddle: http://jsfiddle.net/muthupandiant/ogfLwdwt/

Passing a variable from one php include file to another: global vs. not

When including files in PHP, it acts like the code exists within the file they are being included from. Imagine copy and pasting the code from within each of your included files directly into your index.php. That is how PHP works with includes.

So, in your example, since you've set a variable called $name in your front.inc file, and then included both front.inc and end.inc in your index.php, you will be able to echo the variable $name anywhere after the include of front.inc within your index.php. Again, PHP processes your index.php as if the code from the two files you are including are part of the file.

When you place an echo within an included file, to a variable that is not defined within itself, you're not going to get a result because it is treated separately then any other included file.

In other words, to do the behavior you're expecting, you will need to define it as a global.

How to encode Doctrine entities to JSON in Symfony 2.0 AJAX application?

I just had to solve the same problem: json-encoding an entity ("User") having a One-To-Many Bidirectional Association to another Entity ("Location").

I tried several things and I think now I found the best acceptable solution. The idea was to use the same code as written by David, but somehow intercept the infinite recursion by telling the Normalizer to stop at some point.

I did not want to implement a custom normalizer, as this GetSetMethodNormalizer is a nice approach in my opinion (based on reflection etc.). So I've decided to subclass it, which is not trivial at first sight, because the method to say if to include a property (isGetMethod) is private.

But, one could override the normalize method, so I intercepted at this point, by simply unsetting the property that references "Location" - so the inifinite loop is interrupted.

In code it looks like this:

class GetSetMethodNormalizer extends \Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer {

    public function normalize($object, $format = null)
    {
        // if the object is a User, unset location for normalization, without touching the original object
        if($object instanceof \Leonex\MoveBundle\Entity\User) {
            $object = clone $object;
            $object->setLocations(new \Doctrine\Common\Collections\ArrayCollection());
        }

        return parent::normalize($object, $format);
    }

}

Pandas : compute mean or std (standard deviation) over entire dataframe

You could convert the dataframe to be a single column with stack (this changes the shape from 5x3 to 15x1) and then take the standard deviation:

df.stack().std()         # pandas default degrees of freedom is one

Alternatively, you can use values to convert from a pandas dataframe to a numpy array before taking the standard deviation:

df.values.std(ddof=1)    # numpy default degrees of freedom is zero

Unlike pandas, numpy will give the standard deviation of the entire array by default, so there is no need to reshape before taking the standard deviation.

A couple of additional notes:

The numpy approach here is a bit faster than the pandas one, which is generally true when you have the option to accomplish the same thing with either numpy or pandas. The speed difference will depend on the size of your data, but numpy was roughly 10x faster when I tested a few different sized dataframes on my laptop (numpy version 1.15.4 and pandas version 0.23.4).
The numpy and pandas approaches here will not give exactly the same answers, but will be extremely close (identical at several digits of precision). The discrepancy is due to slight differences in implementation behind the scenes that affect how the floating point values get rounded.

How to make div follow scrolling smoothly with jQuery?

This one is same on facebook:

_x000D_

<script>_x000D_
var valX = $(window).scrollTop();_x000D_
function syncScroll(target){_x000D_
 var valY = $(window).scrollTop();_x000D_
 var difYX = valY - valX;_x000D_
 var targetX = $(target).scrollTop();_x000D_
 if(valY > valX){_x000D_
  $(target).scrollTop(difYX);_x000D_
 }_x000D_
 if(difYX <= 0){_x000D_
  $(target).scrollTop(-20);_x000D_
 }_x000D_
}_x000D_
_x000D_
$(window).scroll(function(){_x000D_
 syncScroll('#demo');_x000D_
})_x000D_
</script>

_x000D_

body{_x000D_
  margin:0;_x000D_
  padding:0;_x000D_
  height:100%;_x000D_
}_x000D_
#demo{_x000D_
  position:fixed;_x000D_
  height:100vh;_x000D_
  overflow:hidden;_x000D_
  width:40%;_x000D_
}_x000D_
#content{_x000D_
  position:relative;_x000D_
  float:right;_x000D_
  width:60%;_x000D_
  color:red; _x000D_
}

_x000D_

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<body>_x000D_
  <div id="demo">_x000D_
    <ul>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
    <ul>_x000D_
  </div>_x000D_
  <div id="content">_x000D_
    <ul>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."</p>_x000D_
      </li>_x000D_
      <li>_x000D_
        <p>_x000D_
"Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?"_x000D_
        </p>_x000D_
      </li>  _x000D_
      <li>_x000D_
        <p>_x000D_
"But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?"_x000D_
        </p>_x000D_
      </li>_x000D_
    <ul>_x000D_
   </div>   _x000D_
</body

_x000D_

Starting a shell in the Docker Alpine container

In case the container is already running:

docker exec -it container_id_or_name ash

Removing object properties with Lodash

To select (or remove) object properties that satisfy a given condition deeply, you can use something like this:

function pickByDeep(object, condition, arraysToo=false) {
  return _.transform(object, (acc, val, key) => {
    if (_.isPlainObject(val) || arraysToo && _.isArray(val)) {
      acc[key] = pickByDeep(val, condition, arraysToo);
    } else if (condition(val, key, object)) {
      acc[key] = val;
    }
  });
}

https://codepen.io/aercolino/pen/MWgjyjm

Output data from all columns in a dataframe in pandas

In ipython, I use this to print a part of the dataframe that works quite well (prints the first 100 rows):

print paramdata.head(100).to_string()

Create Word Document using PHP in Linux

real Word documents

If you need to produce "real" Word documents you need a Windows-based web server and COM automation. I highly recommend Joel's article on this subject.

fake HTTP headers for tricking Word into opening raw HTML

A rather common (but unreliable) alternative is:

header("Content-type: application/vnd.ms-word");
header("Content-Disposition: attachment; filename=document_name.doc");

echo "<html>";
echo "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=Windows-1252\">";
echo "<body>";
echo "<b>Fake word document</b>";
echo "</body>";
echo "</html>"

Make sure you don't use external stylesheets. Everything should be in the same file.

Note that this does not send an actual Word document. It merely tricks browsers into offering it as download and defaulting to a .doc file extension. Older versions of Word may often open this without any warning/security message, and just import the raw HTML into Word. PHP sending sending that misleading Content-Type header along does not constitute a real file format conversion.

Dynamic array in C#

you can use arraylist object from collections class

using System.Collections;

static void Main()
{
  ArrayList arr = new ArrayList();
}

when you want to add elements you can use

arr.Add();

What is the difference between HAVING and WHERE in SQL?

When GROUP BY is not used, the WHERE and HAVING clauses are essentially equivalent.

However, when GROUP BY is used:

The WHERE clause is used to filter records from a result. The filtering occurs before any groupings are made.
The HAVING clause is used to filter values from a group (i.e., to check conditions after aggregation into groups has been performed).

PHP find difference between two datetimes

Sorry my previous answer was wrong. If you are trying to take total elapsed time between time and timeout in the format Y-m-d H:i:s format, take diff between timeout and time in using DateTime object and format it as '%y-%m-%d %H:%i:%s'.

In PHP with PDO, how to check the final SQL parametrized query?

You might be able to use PDOStatement->debugDumpParams. See the PHP documentation .

How to do scanf for single char in C

You have to use a valid variable. ch is not a valid variable for this program. Use char Aaa;

char aaa;
scanf("%c",&Aaa);

Tested and it works.

Convert integer to string Jinja

I found the answer.

Cast integer to string:

myOldIntValue|string

Cast string to integer:

myOldStrValue|int

How to know the git username and email saved during configuration?

List all variables set in the config file, along with their values.

git config --list

If you are new to git then use the following commands to set a user name and email address.

Set user name

git config --global user.name "your Name"

Set user email

git config --global user.email "[email protected]"

Check user name

git config user.name

Check user email

git config user.email

Java division by zero doesnt throw an ArithmeticException - why?

This is behaviour of floating point arithmetic is by specification. Excerpt from the specification, § 15.17.2. Division Operator /:

Division of a nonzero finite value by a zero results in a signed infinity. The sign is determined by the rule stated above.

What's the difference between ConcurrentHashMap and Collections.synchronizedMap(Map)?

Besides what has been suggested, I'd like to post the source code related to SynchronizedMap.

To make a Map thread safe, we can use Collections.synchronizedMap statement and input the map instance as the parameter.

The implementation of synchronizedMap in Collections is like below

   public static <K,V> Map<K,V> synchronizedMap(Map<K,V> m) {
        return new SynchronizedMap<>(m);
    }

As you can see, the input Map object is wrapped by the SynchronizedMap object.
Let's dig into the implementation of SynchronizedMap ,

 private static class SynchronizedMap<K,V>
        implements Map<K,V>, Serializable {
        private static final long serialVersionUID = 1978198479659022715L;

        private final Map<K,V> m;     // Backing Map
        final Object      mutex;        // Object on which to synchronize

        SynchronizedMap(Map<K,V> m) {
            this.m = Objects.requireNonNull(m);
            mutex = this;
        }

        SynchronizedMap(Map<K,V> m, Object mutex) {
            this.m = m;
            this.mutex = mutex;
        }

        public int size() {
            synchronized (mutex) {return m.size();}
        }
        public boolean isEmpty() {
            synchronized (mutex) {return m.isEmpty();}
        }
        public boolean containsKey(Object key) {
            synchronized (mutex) {return m.containsKey(key);}
        }
        public boolean containsValue(Object value) {
            synchronized (mutex) {return m.containsValue(value);}
        }
        public V get(Object key) {
            synchronized (mutex) {return m.get(key);}
        }

        public V put(K key, V value) {
            synchronized (mutex) {return m.put(key, value);}
        }
        public V remove(Object key) {
            synchronized (mutex) {return m.remove(key);}
        }
        public void putAll(Map<? extends K, ? extends V> map) {
            synchronized (mutex) {m.putAll(map);}
        }
        public void clear() {
            synchronized (mutex) {m.clear();}
        }

        private transient Set<K> keySet;
        private transient Set<Map.Entry<K,V>> entrySet;
        private transient Collection<V> values;

        public Set<K> keySet() {
            synchronized (mutex) {
                if (keySet==null)
                    keySet = new SynchronizedSet<>(m.keySet(), mutex);
                return keySet;
            }
        }

        public Set<Map.Entry<K,V>> entrySet() {
            synchronized (mutex) {
                if (entrySet==null)
                    entrySet = new SynchronizedSet<>(m.entrySet(), mutex);
                return entrySet;
            }
        }

        public Collection<V> values() {
            synchronized (mutex) {
                if (values==null)
                    values = new SynchronizedCollection<>(m.values(), mutex);
                return values;
            }
        }

        public boolean equals(Object o) {
            if (this == o)
                return true;
            synchronized (mutex) {return m.equals(o);}
        }
        public int hashCode() {
            synchronized (mutex) {return m.hashCode();}
        }
        public String toString() {
            synchronized (mutex) {return m.toString();}
        }

        // Override default methods in Map
        @Override
        public V getOrDefault(Object k, V defaultValue) {
            synchronized (mutex) {return m.getOrDefault(k, defaultValue);}
        }
        @Override
        public void forEach(BiConsumer<? super K, ? super V> action) {
            synchronized (mutex) {m.forEach(action);}
        }
        @Override
        public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
            synchronized (mutex) {m.replaceAll(function);}
        }
        @Override
        public V putIfAbsent(K key, V value) {
            synchronized (mutex) {return m.putIfAbsent(key, value);}
        }
        @Override
        public boolean remove(Object key, Object value) {
            synchronized (mutex) {return m.remove(key, value);}
        }
        @Override
        public boolean replace(K key, V oldValue, V newValue) {
            synchronized (mutex) {return m.replace(key, oldValue, newValue);}
        }
        @Override
        public V replace(K key, V value) {
            synchronized (mutex) {return m.replace(key, value);}
        }
        @Override
        public V computeIfAbsent(K key,
                Function<? super K, ? extends V> mappingFunction) {
            synchronized (mutex) {return m.computeIfAbsent(key, mappingFunction);}
        }
        @Override
        public V computeIfPresent(K key,
                BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
            synchronized (mutex) {return m.computeIfPresent(key, remappingFunction);}
        }
        @Override
        public V compute(K key,
                BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
            synchronized (mutex) {return m.compute(key, remappingFunction);}
        }
        @Override
        public V merge(K key, V value,
                BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
            synchronized (mutex) {return m.merge(key, value, remappingFunction);}
        }

        private void writeObject(ObjectOutputStream s) throws IOException {
            synchronized (mutex) {s.defaultWriteObject();}
        }
    }

What SynchronizedMap does can be summarized as adding a single lock to primary method of the input Map object. All method guarded by the lock can't be accessed by multiple threads at the same time. That means normal operations like put and get can be executed by a single thread at the same time for all data in the Map object.

It makes the Map object thread safe now but the performance may become an issue in some scenarios.

The ConcurrentMap is far more complicated in the implementation, we can refer to Building a better HashMap for details. In a nutshell, it's implemented taking both thread safe and performance into consideration.

What causes the error "_pickle.UnpicklingError: invalid load key, ' '."?

pickling is recursive, not sequential. Thus, to pickle a list, pickle will start to pickle the containing list, then pickle the first element… diving into the first element and pickling dependencies and sub-elements until the first element is serialized. Then moves on to the next element of the list, and so on, until it finally finishes the list and finishes serializing the enclosing list. In short, it's hard to treat a recursive pickle as sequential, except for some special cases. It's better to use a smarter pattern on your dump, if you want to load in a special way.

The most common pickle, it to pickle everything with a single dump to a file -- but then you have to load everything at once with a single load. However, if you open a file handle and do multiple dump calls (e.g. one for each element of the list, or a tuple of selected elements), then your load will mirror that… you open the file handle and do multiple load calls until you have all the list elements and can reconstruct the list. It's still not easy to selectively load only certain list elements, however. To do that, you'd probably have to store your list elements as a dict (with the index of the element or chunk as the key) using a package like klepto, which can break up a pickled dict into several files transparently, and enables easy loading of specific elements.

Saving and loading multiple objects in pickle file?

Laravel Eloquent inner join with multiple conditions

You can see the following code to solved the problem

return $query->join('kg_shops', function($join)
{
    $join->on('kg_shops.id', '=', 'kg_feeds.shop_id');
    $join->where('kg_shops.active','=', 1);
});

Or another way to solved it

 return $query->join('kg_shops', function($join)
{
    $join->on('kg_shops.id', '=', 'kg_feeds.shop_id');
    $join->on('kg_shops.active','=', DB::raw('1'));
});

Execute a terminal command from a Cocoa app

fork, exec, and wait should work, if you're not really looking for a Objective-C specific way. fork creates a copy of the currently running program, exec replaces the currently running program with a new one, and wait waits for the subprocess to exit. For example (without any error checking):

#include <stdlib.h>
#include <unistd.h>

pid_t p = fork();
if (p == 0) {
    /* fork returns 0 in the child process. */
    execl("/other/program/to/run", "/other/program/to/run", "foo", NULL);
} else {
    /* fork returns the child's PID in the parent. */
    int status;
    wait(&status);
    /* The child has exited, and status contains the way it exited. */
}

/* The child has run and exited by the time execution gets to here. */

There's also system, which runs the command as if you typed it from the shell's command line. It's simpler, but you have less control over the situation.

I'm assuming you're working on a Mac application, so the links are to Apple's documentation for these functions, but they're all POSIX, so you should be to use them on any POSIX-compliant system.

Fastest way to remove non-numeric characters from a VARCHAR in SQL Server

I saw this solution with T-SQL code and PATINDEX. I like it :-)

CREATE Function [fnRemoveNonNumericCharacters](@strText VARCHAR(1000))
RETURNS VARCHAR(1000)
AS
BEGIN
    WHILE PATINDEX('%[^0-9]%', @strText) > 0
    BEGIN
        SET @strText = STUFF(@strText, PATINDEX('%[^0-9]%', @strText), 1, '')
    END
    RETURN @strText
END

PDO support for multiple queries (PDO_MYSQL, PDO_MYSQLND)

Tried following code

 $db = new PDO("mysql:host={$dbhost};dbname={$dbname};charset=utf8", $dbuser, $dbpass, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));

Then

 try {
 $db->query('SET NAMES gbk');
 $stmt = $db->prepare('SELECT * FROM 2_1_paidused WHERE NumberRenamed = ? LIMIT 1');
 $stmt->execute(array("\xbf\x27 OR 1=1 /*"));
 }
 catch (PDOException $e){
 echo "DataBase Errorz: " .$e->getMessage() .'<br>';
 }
 catch (Exception $e) {
 echo "General Errorz: ".$e->getMessage() .'<br>';
 }

And got

DataBase Errorz: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '/*' LIMIT 1' at line 1

If added $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); after $db = ...

Then got blank page

If instead SELECT tried DELETE, then in both cases got error like

 DataBase Errorz: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '* FROM 2_1_paidused WHERE NumberRenamed = '¿\' OR 1=1 /*' LIMIT 1' at line 1

So my conclusion that no injection possible...

Updating a dataframe column in spark

importing col, when from pyspark.sql.functions and updating fifth column to integer(0,1,2) based on the string(string a, string b, string c) into a new DataFrame.

from pyspark.sql.functions import col, when 

data_frame_temp = data_frame.withColumn("col_5",when(col("col_5") == "string a", 0).when(col("col_5") == "string b", 1).otherwise(2))

Should Gemfile.lock be included in .gitignore?

Assuming you're not writing a rubygem, Gemfile.lock should be in your repository. It's used as a snapshot of all your required gems and their dependencies. This way bundler doesn't have to recalculate all the gem dependencies each time you deploy, etc.

From cowboycoded's comment below:

If you are working on a gem, then DO NOT check in your Gemfile.lock. If you are working on a Rails app, then DO check in your Gemfile.lock.

Here's a nice article explaining what the lock file is.

JQuery Number Formatting

I would recommend looking at this article on how to use javascript to handle basic formatting:

function addCommas(nStr)
{
    nStr += '';
    x = nStr.split('.');
    x1 = x[0];
    x2 = x.length > 1 ? '.' + x[1] : '';
    var rgx = /(\d+)(\d{3})/;
    while (rgx.test(x1)) {
        x1 = x1.replace(rgx, '$1' + ',' + '$2');
    }
    return x1 + x2;
}

source: http://www.mredkj.com/javascript/numberFormat.html

While jQuery can make your life easier in a million different ways I would say it's overkill for this. Keep in mind that jQuery can be fairly large and your user's browser needs to download it when you use it on a page.

When ever using jQuery you should step back and ask if it contributes enough to justify the extra overhead of downloading the library.

If you need some sort of advanced formatting (like the localization stuff in the plugin you linked), or you are already including jQuery it might be worth looking at a jQuery plugin.

Side note - check this out if you want to get a chuckle about the over use of jQuery.

Which Architecture patterns are used on Android?

Update November 2018

After working and blogging about MVC and MVP in Android for several years (see the body of the answer below), I decided to capture my knowledge and understanding in a more comprehensive and easily digestible form.

So, I released a full blown video course about Android applications architecture. So, if you're interested in mastering the most advanced architectural patterns in Android development, check out this comprehensive course here.

This answer was updated in order to remain relevant as of November 2016

It looks like you are seeking for architectural patterns rather than design patterns.

Design patterns aim at describing a general "trick" that programmer might implement for handling a particular set of recurring software tasks. For example: In OOP, when there is a need for an object to notify a set of other objects about some events, the observer design pattern can be employed.

Since Android applications (and most of AOSP) are written in Java, which is object-oriented, I think you'll have a hard time looking for a single OOP design pattern which is NOT used on Android.

Architectural patterns, on the other hand, do not address particular software tasks - they aim to provide templates for software organization based on the use cases of the software component in question.

It sounds a bit complicated, but I hope an example will clarify: If some application will be used to fetch data from a remote server and present it to the user in a structured manner, then MVC might be a good candidate for consideration. Note that I said nothing about software tasks and program flow of the application - I just described it from user's point of view, and a candidate for an architectural pattern emerged.

Since you mentioned MVC in your question, I'd guess that architectural patterns is what you're looking for.

Historically, there were no official guidelines by Google about applications' architectures, which (among other reasons) led to a total mess in the source code of Android apps. In fact, even today most applications that I see still do not follow OOP best practices and do not show a clear logical organization of code.

But today the situation is different - Google recently released the Data Binding library, which is fully integrated with Android Studio, and, even, rolled out a set of architecture blueprints for Android applications.

Two years ago it was very hard to find information about MVC or MVP on Android. Today, MVC, MVP and MVVM has become "buzz-words" in the Android community, and we are surrounded by countless experts which constantly try to convince us that MVx is better than MVy. In my opinion, discussing whether MVx is better than MVy is totally pointless because the terms themselves are very ambiguous - just look at the answers to this question, and you'll realize that different people can associate these abbreviations with completely different constructs.

Due to the fact that a search for a best architectural pattern for Android has officially been started, I think we are about to see several more ideas come to light. At this point, it is really impossible to predict which pattern (or patterns) will become industry standards in the future - we will need to wait and see (I guess it is matter of a year or two).

However, there is one prediction I can make with a high degree of confidence: Usage of the Data Binding library will not become an industry standard. I'm confident to say that because the Data Binding library (in its current implementation) provides short-term productivity gains and some kind of architectural guideline, but it will make the code non-maintainable in the long run. Once long-term effects of this library will surface - it will be abandoned.

Now, although we do have some sort of official guidelines and tools today, I, personally, don't think that these guidelines and tools are the best options available (and they are definitely not the only ones). In my applications I use my own implementation of an MVC architecture. It is simple, clean, readable and testable, and does not require any additional libraries.

This MVC is not just cosmetically different from others - it is based on a theory that Activities in Android are not UI Elements, which has tremendous implications on code organization.

So, if you're looking for a good architectural pattern for Android applications that follows SOLID principles, you can find a description of one in my post about MVC and MVP architectural patterns in Android.

How do I implement a callback in PHP?

The manual uses the terms "callback" and "callable" interchangeably, however, "callback" traditionally refers to a string or array value that acts like a function pointer, referencing a function or class method for future invocation. This has allowed some elements of functional programming since PHP 4. The flavors are:

$cb1 = 'someGlobalFunction';
$cb2 = ['ClassName', 'someStaticMethod'];
$cb3 = [$object, 'somePublicMethod'];

// this syntax is callable since PHP 5.2.3 but a string containing it
// cannot be called directly
$cb2 = 'ClassName::someStaticMethod';
$cb2(); // fatal error

// legacy syntax for PHP 4
$cb3 = array(&$object, 'somePublicMethod');

This is a safe way to use callable values in general:

if (is_callable($cb2)) {
    // Autoloading will be invoked to load the class "ClassName" if it's not
    // yet defined, and PHP will check that the class has a method
    // "someStaticMethod". Note that is_callable() will NOT verify that the
    // method can safely be executed in static context.

    $returnValue = call_user_func($cb2, $arg1, $arg2);
}

Modern PHP versions allow the first three formats above to be invoked directly as $cb(). call_user_func and call_user_func_array support all the above.

See: http://php.net/manual/en/language.types.callable.php

Notes/Caveats:

If the function/class is namespaced, the string must contain the fully-qualified name. E.g. ['Vendor\Package\Foo', 'method']
call_user_func does not support passing non-objects by reference, so you can either use call_user_func_array or, in later PHP versions, save the callback to a var and use the direct syntax: $cb();
Objects with an __invoke() method (including anonymous functions) fall under the category "callable" and can be used the same way, but I personally don't associate these with the legacy "callback" term.
The legacy create_function() creates a global function and returns its name. It's a wrapper for eval() and anonymous functions should be used instead.

How to detect Esc Key Press in React and how to handle it

React uses SyntheticKeyboardEvent to wrap native browser event and this Synthetic event provides named key attribute,
which you can use like this:

handleOnKeyDown = (e) => {
  if (['Enter', 'ArrowRight', 'Tab'].includes(e.key)) {
    // select item
    e.preventDefault();
  } else if (e.key === 'ArrowUp') {
    // go to top item
    e.preventDefault();
  } else if (e.key === 'ArrowDown') {
    // go to bottom item
    e.preventDefault();
  } else if (e.key === 'Escape') {
    // escape
    e.preventDefault();
  }
};

How do you copy the contents of an array to a std::vector in C++ without looping?

Since I can only edit my own answer, I'm going to make a composite answer from the other answers to my question. Thanks to all of you who answered.

Using std::copy, this still iterates in the background, but you don't have to type out the code.

int foo(int* data, int size)
{
   static std::vector<int> my_data; //normally a class variable
   std::copy(data, data + size, std::back_inserter(my_data));
   return 0;
}

Using regular memcpy. This is probably best used for basic data types (i.e. int) but not for more complex arrays of structs or classes.

vector<int> x(size);
memcpy(&x[0], source, size*sizeof(int));

Prevent cell numbers from incrementing in a formula in Excel

There is something called 'locked reference' in excel which you can use for this, and you use $ symbols to lock a range. For your example, you would use:

=IF(B4<>"",B4/B$1,"")

This locks the 1 in B1 so that when you copy it to rows below, 1 will remain the same.

If you use $B$1, the range will not change when you copy it down a row or across a column.

Switch statement fall-through...should it be allowed?

As with anything: if used with care, it can be an elegant tool.

However, I think the drawbacks more than justify not to use it, and finally not to allow it anymore (C#). Among the problems are:

it's easy to "forget" a break
it's not always obvious for code maintainers that an omitted break was intentional

Good use of a switch/case fall-through:

switch (x)
{
case 1:
case 2:
case 3:
 Do something
 break;
}

Baaaaad use of a switch/case fall-through:

switch (x)
{
case 1:
    Some code
case 2:
    Some more code
case 3:
    Even more code
    break;
}

This can be rewritten using if/else constructs with no loss at all in my opinion.

My final word: stay away from fall-through case labels as in the bad example, unless you are maintaining legacy code where this style is used and well understood.

How to append one file to another in Linux from the shell?

cat can be the easy solution but that become very slow when we concat large files, find -print is to rescue you, though you have to use cat once.

amey@xps ~/work/python/tmp $ ls -lhtr
total 969M
-rw-r--r-- 1 amey amey 485M May 24 23:54 bigFile2.txt
-rw-r--r-- 1 amey amey 485M May 24 23:55 bigFile1.txt

 amey@xps ~/work/python/tmp $ time cat bigFile1.txt bigFile2.txt >> out.txt

real    0m3.084s
user    0m0.012s
sys     0m2.308s


amey@xps ~/work/python/tmp $ time find . -maxdepth 1 -type f -name 'bigFile*' -print0 | xargs -0 cat -- > outFile1

real    0m2.516s
user    0m0.028s
sys     0m2.204s

With ' N ' no of nodes, how many different Binary and Binary Search Trees possible?

Eric Lippert recently had a very in-depth series of blog posts about this: "Every Binary Tree There Is" and "Every Tree There Is" (plus some more after that).

In answer to your specific question, he says:

The number of binary trees with n nodes is given by the Catalan numbers, which have many interesting properties. The nth Catalan number is determined by the formula (2n)! / (n+1)!n!, which grows exponentially.

Bash Script : what does #!/bin/bash mean?

That is called a shebang, it tells the shell what program to interpret the script with, when executed.

In your example, the script is to be interpreted and run by the bash shell.

Some other example shebangs are:

(From Wikipedia)

#!/bin/sh — Execute the file using sh, the Bourne shell, or a compatible shell
#!/bin/csh — Execute the file using csh, the C shell, or a compatible shell
#!/usr/bin/perl -T — Execute using Perl with the option for taint checks
#!/usr/bin/php — Execute the file using the PHP command line interpreter
#!/usr/bin/python -O — Execute using Python with optimizations to code
#!/usr/bin/ruby — Execute using Ruby

and a few additional ones I can think off the top of my head, such as:

#!/bin/ksh
#!/bin/awk
#!/bin/expect

In a script with the bash shebang, for example, you would write your code with bash syntax; whereas in a script with expect shebang, you would code it in expect syntax, and so on.

Response to updated portion:

It depends on what /bin/sh actually points to on your system. Often it is just a symlink to /bin/bash. Sometimes portable scripts are written with #!/bin/sh just to signify that it's a shell script, but it uses whichever shell is referred to by /bin/sh on that particular system (maybe it points to /bin/bash, /bin/ksh or /bin/zsh)

PHP - Move a file into a different folder on the server

If you want to move the file in new path with keep original file name. use this:

$source_file = 'foo/image.jpg';
$destination_path = 'bar/';
rename($source_file, $destination_path . pathinfo($source_file, PATHINFO_BASENAME));

How to declare a global variable in React?

Why don't you try using Context?

You can declare a global context variable in any of the parent components and this variable will be accessible across the component tree by this.context.varname. You only have to specify childContextTypes and getChildContext in the parent component and thereafter you can use/modify this from any component by just specifying contextTypes in the child component.

However, please take a note of this as mentioned in docs:

Just as global variables are best avoided when writing clear code, you should avoid using context in most cases. In particular, think twice before using it to "save typing" and using it instead of passing explicit props.

Get second child using jQuery

_{It's surprising to see that nobody mentioned the native JS way to do this..}

Without jQuery:

Just access the children property of the parent element. It will return a live HTMLCollection of children elements which can be accessed by an index. If you want to get the second child:

parentElement.children[1];

In your case, something like this could work: (example)

var secondChild = document.querySelector('.parent').children[1];

console.log(secondChild); // <td>element two</td>

<table>
    <tr class="parent">
        <td>element one</td>
        <td>element two</td>
    </tr>
</table>

You can also use a combination of CSS3 selectors / querySelector() and utilize :nth-of-type(). This method may work better in some cases, because you can also specifiy the element type, in this case td:nth-of-type(2) (example)

var secondChild = document.querySelector('.parent > td:nth-of-type(2)');

console.log(secondChild); // <td>element two</td>

dlib installation on Windows 10

It is basically a two-step process:

install cmap

pip install cmap

install dlib

pip install https://pypi.python.org/packages/da/06/bd3e241c4eb0a662914b3b4875fc52dd176a9db0d4a2c915ac2ad8800e9e/dlib-19.7.0-cp36-cp36m-win_amd64.whl#md5=b7330a5b2d46420343fbed5df69e6a3f

What is the equivalent of Select Case in Access SQL?

Consider the Switch Function as an alternative to multiple IIf() expressions. It will return the value from the first expression/value pair where the expression evaluates as True, and ignore any remaining pairs. The concept is similar to the SELECT ... CASE approach you referenced but which is not available in Access SQL.

If you want to display a calculated field as commission:

SELECT
    Switch(
        OpeningBalance < 5001, 20,
        OpeningBalance < 10001, 30,
        OpeningBalance < 20001, 40,
        OpeningBalance >= 20001, 50
        ) AS commission
FROM YourTable;

If you want to store that calculated value to a field named commission:

UPDATE YourTable
SET commission =
    Switch(
        OpeningBalance < 5001, 20,
        OpeningBalance < 10001, 30,
        OpeningBalance < 20001, 40,
        OpeningBalance >= 20001, 50
        );

Either way, see whether you find Switch() easier to understand and manage. Multiple IIf()s can become mind-boggling as the number of conditions grows.

Dictionary with list of strings as value

Just create a new array in your dictionary

Dictionary<string, List<string>> myDic = new Dictionary<string, List<string>>();
myDic.Add(newKey, new List<string>(existingList));

jQuery - keydown / keypress /keyup ENTERKEY detection?

I think you'll struggle with keyup event - as it first triggers keypress - and you won't be able to stop the propagation of the second one if you want to exclude the Enter Key.

Difference between arguments and parameters in Java

There are different points of view. One is they are the same. But in practice, we need to differentiate formal parameters (declarations in the method's header) and actual parameters (values passed at the point of invocation). While phrases "formal parameter" and "actual parameter" are common, "formal argument" and "actual argument" are not used. This is because "argument" is used mainly to denote "actual parameter". As a result, some people insist that "parameter" can denote only "formal parameter".

How do I deserialize a complex JSON object in C# .NET?

If you use C# 2010 or newer, you can use dynamic type:

dynamic json = Newtonsoft.Json.JsonConvert.DeserializeObject(jsonstring);

Then you can access attributes and arrays in dynamic object using dot notation:

string nemo = json.response[0].images[0].report.nemo;

What is git fast-forwarding?

When you try to merge one commit with a commit that can be reached by following the first commit’s history, Git simplifies things by moving the pointer forward because there is no divergent work to merge together – this is called a “fast-forward.”

For more : http://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging

In another way,

If Master has not diverged, instead of creating a new commit, git will just point master to the latest commit of the feature branch. This is a “fast forward.”

There won't be any "merge commit" in fast-forwarding merge.

How to use a table type in a SELECT FROM statement?

In SQL you may only use table type which is defined at schema level (not at package or procedure level), and index-by table (associative array) cannot be defined at schema level. So - you have to define nested table like this

create type exch_row as object (
    currency_cd VARCHAR2(9),
    exch_rt_eur NUMBER,
    exch_rt_usd NUMBER);

create type exch_tbl as table of exch_row;

And then you can use it in SQL with TABLE operator, for example:

declare
   l_row     exch_row;
   exch_rt   exch_tbl;
begin
   l_row := exch_row('PLN', 100, 100);
   exch_rt  := exch_tbl(l_row);

   for r in (select i.*
               from item i, TABLE(exch_rt) rt
              where i.currency = rt.currency_cd) loop
      -- your code here
   end loop;
end;
/

How to get current date & time in MySQL?

You can use NOW():

INSERT INTO servers (server_name, online_status, exchange, disk_space, network_shares, c_time)
VALUES('m1', 'ONLINE', 'exchange', 'disk_space', 'network_shares', NOW())

How to change time in DateTime?

Try this one

var NewDate = Convert.ToDateTime(DateTime.Now.ToString("dd/MMM/yyyy")+" "+"10:15 PM")/*Add your time here*/;

How to "EXPIRE" the "HSET" child key in redis?

Regarding a NodeJS implementation, I have added a custom expiryTime field in the object I save in the HASH. Then after a specific period time, I clear the expired HASH entries by using the following code:

client.hgetall(HASH_NAME, function(err, reply) {
    if (reply) {
        Object.keys(reply).forEach(key => {
            if (reply[key] && JSON.parse(reply[key]).expiryTime < (new Date).getTime()) {
                client.hdel(HASH_NAME, key);
            }
        })
    }
});

DB2 Query to retrieve all table names for a given schema

You can also get the table names simply by typing LIST TABLES in DB2

How to return a table from a Stored Procedure?

In SQL Server 2008 you can use

http://www.sommarskog.se/share_data.html#tableparam

or else simple and same as common execution

CREATE PROCEDURE OrderSummary @MaxQuantity INT OUTPUT AS

SELECT Ord.EmployeeID, SummSales = SUM(OrDet.UnitPrice * OrDet.Quantity)
FROM Orders AS Ord
     JOIN [Order Details] AS OrDet ON (Ord.OrderID = OrDet.OrderID)
GROUP BY Ord.EmployeeID
ORDER BY Ord.EmployeeID

SELECT @MaxQuantity = MAX(Quantity) FROM [Order Details]

RETURN (SELECT SUM(Quantity) FROM [Order Details])
GO

I hopes its help to you

how to read a long multiline string line by line in python

This answer fails in a couple of edge cases (see comments). The accepted solution above will handle these. str.splitlines() is the way to go. I will leave this answer nevertheless as reference.

Old (incorrect) answer:

s =  \
"""line1
line2
line3
"""

lines = s.split('\n')
print(lines)
for line in lines:
    print(line)

How to change an element's title attribute using jQuery

jqueryTitle({
    title: 'New Title'
});

for first title:

jqueryTitle('destroy');

https://github.com/ertaserdi/jQuery-Title

Moving from JDK 1.7 to JDK 1.8 on Ubuntu

This is what I do on debian - I suspect it should work on ubuntu (amend the version as required + adapt the folder where you want to copy the JDK files as you wish, I'm using /opt/jdk):

wget --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u71-b15/jdk-8u71-linux-x64.tar.gz
sudo mkdir /opt/jdk
sudo tar -zxf jdk-8u71-linux-x64.tar.gz -C /opt/jdk/
rm jdk-8u71-linux-x64.tar.gz

Then update-alternatives:

sudo update-alternatives --install /usr/bin/java java /opt/jdk/jdk1.8.0_71/bin/java 1
sudo update-alternatives --install /usr/bin/javac javac /opt/jdk/jdk1.8.0_71/bin/javac 1

Select the number corresponding to the /opt/jdk/jdk1.8.0_71/bin/java when running the following commands:

sudo update-alternatives --config java
sudo update-alternatives --config javac

Finally, verify that the correct version is selected:

java -version
javac -version

Multiline strings in VB.NET

Use vbCrLf or vbNewLine. It works with MessageBoxes and many other controls I tested.

Dim str As String
str = "First line" & vbCrLf & "Second line"
MsgBox(str)
str = "First line" & vbNewLine & "Second line"
MsgBox(str)

It will show two identical MessageBoxes with 2 lines.

Get a substring of a char*

Use char* strncpy(char* dest, char* src, int n) from <cstring>. In your case you will need to use the following code:

char* substr = malloc(4);
strncpy(substr, buff+10, 4);

Full documentation on the strncpy function here.

How can I detect Internet Explorer (IE) and Microsoft Edge using JavaScript?

One line code to detect the browser.

If the browser is IE or Edge, It will return true;

let isIE = /edge|msie\s|trident\//i.test(window.navigator.userAgent)

Bundling data files with PyInstaller (--onefile)

All of the other answers use the current working directory in the case where the application is not PyInstalled (i.e. sys._MEIPASS is not set). That is wrong, as it prevents you from running your application from a directory other than the one where your script is.

A better solution:

import sys
import os

def resource_path(relative_path):
    """ Get absolute path to resource, works for dev and for PyInstaller """
    base_path = getattr(sys, '_MEIPASS', os.path.dirname(os.path.abspath(__file__)))
    return os.path.join(base_path, relative_path)

Android - Spacing between CheckBox and text

I end up with this issue by changing the images. Just added extra transparent background in png files. This solution works excellent on all the APIs.

Build and Install unsigned apk on device without the development server?

As of react-native 0.57, none of the previously provided answers will work anymore, as the directories in which gradle expects to find the bundle and the assets have changed.

Simple way without react-native bundle

The simplest way to build a debug build is without using the react-native bundle command at all, but by simply modifying your app/build.gradle file.

Inside the project.ext.react map in the app/build.gradle file, add the bundleInDebug: true entry. If you want it to not be a --dev build (no warnings and minified bundle) then you should also add the devDisabledInDebug: true entry to the same map.

With react-native bundle

If for some reason you need to or want to use the react-native bundle command to create the bundle and then the ./gradlew assembleDebug to create the APK with the bundle and the assets you have to make sure to put the bundle and the assets in the correct paths, where gradle can find them.

As of react-native 0.57 those paths are android/app/build/generated/assets/react/debug/index.android.js for the bundle

and android/app/build/generated/res/react/debug for the assets. So the full commands for manually bundling and building the APK with the bundle and assets are:

react-native bundle --dev false --platform android --entry-file index.js --bundle-output ./android/app/build/generated/assets/react/debug/index.android.bundle --assets-dest ./android/app/build/res/react/debug

and then

./gradlew assembleDebug

Bundle and assets path

Note that that paths where gradle looks for the bundle and the assets might be subject to change. To find out where those paths are, look at the react.gradle file in your node_modules/react-native directory. The lines starting with def jsBundleDir = and def resourcesDir = specify the directories where gradle looks for the bundle and the assets respectively.

Can I use jQuery to check whether at least one checkbox is checked?

$("#frmTest").submit(function(){
    var checked = $("#frmText input:checked").length > 0;
    if (!checked){
        alert("Please check at least one checkbox");
        return false;
    }
});

How do I plot in real-time in a while loop using matplotlib?

Here's the working version of the code in question (requires at least version Matplotlib 1.1.0 from 2011-11-14):

import numpy as np
import matplotlib.pyplot as plt

plt.axis([0, 10, 0, 1])

for i in range(10):
    y = np.random.random()
    plt.scatter(i, y)
    plt.pause(0.05)

plt.show()

Note some of the changes:

Call plt.pause(0.05) to both draw the new data and it runs the GUI's event loop (allowing for mouse interaction).

Show tables, describe tables equivalent in redshift

In the following post, I documented queries to retrieve TABLE and COLUMN comments from Redshift. https://sqlsylvia.wordpress.com/2017/04/29/redshift-comment-views-documenting-data/

Enjoy!

Table Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , CASE WHEN c.relkind = 'v' THEN 'view' ELSE 'table' END 
       AS table_type
     , d.description AS table_description
     FROM pg_class As c
     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
     LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
     LEFT JOIN pg_description As d 
          ON (d.objoid = c.oid AND d.objsubid = 0)
     WHERE c.relkind IN('r', 'v') AND d.description > ''
     ORDER BY n.nspname, c.relname ;

Column Comments

    SELECT n.nspname AS schema_name
     , pg_get_userbyid(c.relowner) AS table_owner
     , c.relname AS table_name
     , a.attname AS column_name
     , d.description AS column_description
    FROM pg_class AS c
    INNER JOIN pg_attribute As a ON c.oid = a.attrelid
    INNER JOIN pg_namespace n ON n.oid = c.relnamespace
    LEFT JOIN pg_tablespace t ON t.oid = c.reltablespace
    LEFT JOIN pg_description As d 
     ON (d.objoid = c.oid AND d.objsubid = a.attnum)
    WHERE c.relkind IN('r', 'v')
     AND a.attname NOT         
     IN ('cmax', 'oid', 'cmin', 'deletexid', 'ctid', 'tableoid','xmax', 'xmin', 'insertxid')
    ORDER BY n.nspname, c.relname, a.attname;

Compiling C++ on remote Linux machine - "clock skew detected" warning

I have had this in the past - due to the clocks being out on the machines. Consider setting up NTP so that all machines have the same time.

What is the difference between .text, .value, and .value2?

target.Value will give you a Variant type

target.Value2 will give you a Variant type as well but a Date is coerced to a Double

target.Text attempts to coerce to a String and will fail if the underlying Variant is not coercable to a String type

The safest thing to do is something like

Dim v As Variant
v = target.Value 'but if you don't want to handle date types use Value2

And check the type of the variant using VBA.VarType(v) before you attempt an explicit coercion.

Programs & Examples On #Ultraseek

How can I use Python to get the system hostname?

Why is vertical-align: middle not working on my span or div?

Calling one Activity from another in Android

Selenium: WebDriverException:Chrome failed to start: crashed as google-chrome is no longer running so ChromeDriver is assuming that Chrome has crashed

Maximum call stack size exceeded error

Dynamic height for DIV

How to print out a variable in makefile

Hibernate Error executing DDL via JDBC Statement

forEach is not a function error with JavaScript array

Removing the remembered login and password list in SQL Server Management Studio

List of all unique characters in a string?

Writing html form data to a txt file without the use of a webserver

Git merge with force overwrite

get client time zone from browser

How does the Spring @ResponseBody annotation work?

javascript set cookie with expire time

MySQL Calculate Percentage

Making the iPhone vibrate

how to clear the screen in python

Python None comparison: should I use "is" or ==?

beyond top level package error in relative import

Set width to match constraints in ConstraintLayout

Why is __init__() always called after __new__()?

Disable submit button ONLY after submit

psql: FATAL: role "postgres" does not exist

CSS: fixed to bottom and centered

Partly cherry-picking a commit with Git

How to use confirm using sweet alert?

Undefined behavior and sequence points

Is it true that there are no Sequence Points in C++11?

What exactly is this 'Sequenced before' thing?

What is the meaning of the word 'evaluation' in context of C++11?

So there must be some relation between Undefined Behaviour and the above-mentioned things, right?

Paging with Oracle

How do I kill this tomcat process in Terminal?

SQL Server String or binary data would be truncated

Positioning <div> element at center of screen

Convert char* to string C++

What exactly is the meaning of an API?

Convert Select Columns in Pandas Dataframe to Numpy Array

C++ - Assigning null to a std::string

Server.MapPath("."), Server.MapPath("~"), Server.MapPath(@"\"), Server.MapPath("/"). What is the difference?

C# getting its own class name

How do I address unchecked cast warnings?

Rolling back local and remote git repository by 1 commit

Getting execute permission to xp_cmdshell

Java string split with "." (dot)

Removing an element from an Array (Java)

Mockito matcher and array of primitives

How do I get a file name from a full path with PHP?

Unable to read data from the transport connection : An existing connection was forcibly closed by the remote host

How to find the index of an element in an array in Java?

What is the cleanest way to get the progress of JQuery ajax request?

What is the difference between Hibernate and Spring Data JPA

What is the proper REST response code for a valid request but an empty data?

Bootstrap: Open Another Modal in Modal

How to make a node.js application run permanently?

Socket accept - "Too many open files"

Return single column from a multi-dimensional array

Calling a Javascript Function from Console

Which HTTP methods match up to which CRUD methods?

pandas: multiple conditions while indexing data frame - unexpected behavior

Where are the recorded macros stored in Notepad++?

Color theme for VS Code integrated terminal

Remove Object from Array using JavaScript

How to convert Varchar to Double in sql?

Django 1.7 throws django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet

correct way to define class variables in Python

JavaScript Uncaught ReferenceError: jQuery is not defined; Uncaught ReferenceError: $ is not defined

Simple function to sort an array of objects

Log4j: How to configure simplest possible file logging?

How to find a text inside SQL Server procedures / triggers?

pip or pip3 to install packages for Python 3?

syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING

Cannot use string offset as an array in php

ReferenceError: $ is not defined

HTML-parser on Node.js

Dynamically change bootstrap progress bar value when checkboxes checked

How to make a checkbox checked with jQuery?

Why is init() always called after new()?