How to show shadow around the linearlayout in Android?

i know this is way too late. but i had the same requirement. i solved like this

<android.support.v7.widget.CardView
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:cardUseCompatPadding="true"
app:cardElevation="4dp"
app:cardCornerRadius="3dp" >

<!-- put whatever you want -->

</android.support.v7.widget.CardView>

you need to add dependency:

compile 'com.android.support:cardview-v7:25.0.1'

Oracle row count of table by count(*) vs NUM_ROWS from DBA_TABLES

According to the documentation NUM_ROWS is the "Number of rows in the table", so I can see how this might be confusing. There, however, is a major difference between these two methods.

This query selects the number of rows in MY_TABLE from a system view. This is data that Oracle has previously collected and stored.

select num_rows from all_tables where table_name = 'MY_TABLE'

This query counts the current number of rows in MY_TABLE

select count(*) from my_table

By definition they are difference pieces of data. There are two additional pieces of information you need about NUM_ROWS.

In the documentation there's an asterisk by the column name, which leads to this note:

Columns marked with an asterisk (*) are populated only if you collect statistics on the table with the ANALYZE statement or the DBMS_STATS package.

This means that unless you have gathered statistics on the table then this column will not have any data.
Statistics gathered in 11g+ with the default estimate_percent, or with a 100% estimate, will return an accurate number for that point in time. But statistics gathered before 11g, or with a custom estimate_percent less than 100%, uses dynamic sampling and may be incorrect. If you gather 99.999% a single row may be missed, which in turn means that the answer you get is incorrect.

If your table is never updated then it is certainly possible to use ALL_TABLES.NUM_ROWS to find out the number of rows in a table. However, and it's a big however, if any process inserts or deletes rows from your table it will be at best a good approximation and depending on whether your database gathers statistics automatically could be horribly wrong.

Generally speaking, it is always better to actually count the number of rows in the table rather then relying on the system tables.

Add Keypair to existing EC2 instance

Once an instance has been started, there is no way to change the keypair associated with the instance at a meta data level, but you can change what ssh key you use to connect to the instance.

stackoverflow.com/questions/7881469/change-key-pair-for-ec2-instance

LINQ to SQL using GROUP BY and COUNT(DISTINCT)

This is how you do a distinct count query. Note that you have to filter out the nulls.

var useranswercount = (from a in tpoll_answer
where user_nbr != null && answer_nbr != null
select user_nbr).Distinct().Count();

If you combine this with into your current grouping code, I think you'll have your solution.

Facebook Javascript SDK Problem: "FB is not defined"

Facebook prefers that you load their SDK asynchronously so that it doesn't block any other scripts that you need for your page but due to the iframe there's a chance that the console tries to call a method on the FB object before the FB object is completely created even though FB is only called in the fbAsyncInit function.
Try loading the javascript synchronously and you shouldn't get the error anymore. To do this you can copy and paste the code that Facebook provides and place it in an external .js file and then include that .js file in a <script> tag in the <head> of your page. If you must load their SDK asynchronously then check for FB to be created first before calling the init function.

How to use UIVisualEffectView to Blur Image?

I prefer creating Visual Effects via Storyboard - no code used for creating or maintaining UI Elements. It gives me full landscape support, too. I have made a little demo of using UIVisualEffects with Blur and also Vibrancy.

Demo on Github

<ng-container> vs <template>

Edit : Now it is documented

<ng-container> to the rescue

The Angular <ng-container> is a grouping element that doesn't interfere with styles or layout because Angular doesn't put it in the DOM.

(...)

The <ng-container> is a syntax element recognized by the Angular parser. It's not a directive, component, class, or interface. It's more like the curly braces in a JavaScript if-block:
  if (someCondition) {
      statement1; 
      statement2;
      statement3;
     }
Without those braces, JavaScript would only execute the first statement when you intend to conditionally execute all of them as a single block. The <ng-container> satisfies a similar need in Angular templates.

Original answer:

According to this pull request :

<ng-container> is a logical container that can be used to group nodes but is not rendered in the DOM tree as a node.

<ng-container> is rendered as an HTML comment.

so this angular template :

<div>
    <ng-container>foo</ng-container>
<div>

will produce this kind of output :

<div>
    <!--template bindings={}-->foo
<div>

So ng-container is useful when you want to conditionaly append a group of elements (ie using *ngIf="foo") in your application but don't want to wrap them with another element.

<div>
    <ng-container *ngIf="true">
        <h2>Title</h2>
        <div>Content</div>
    </ng-container>
</div>

will then produce :

<div>
    <h2>Title</h2>
    <div>Content</div>
</div>

Import PEM into Java Key Store

First, convert your certificate in a DER format :

openssl x509 -outform der -in certificate.pem -out certificate.der

And after, import it in the keystore :

keytool -import -alias your-alias -keystore cacerts -file certificate.der

Is it possible to insert HTML content in XML document?

You can include HTML content. One possibility is encoding it in BASE64 as you have mentioned.

Another might be using CDATA tags.

Example using CDATA:

<xml>
    <title>Your HTML title</title>
    <htmlData><![CDATA[<html>
        <head>
            <script/>
        </head>
        <body>
        Your HTML's body
        </body>
        </html>
     ]]>
    </htmlData>
</xml>

Please note:

CDATA's opening character sequence: <![CDATA[

CDATA's closing character sequence: ]]>

How to force Hibernate to return dates as java.util.Date instead of Timestamp?

Approaches 1 and 2 obviously don't work, because you get java.sql.Date objects, per JPA/Hibernate spec, and not java.util.Date. From approaches 3 and 4, I would rather choose the latter one, because it's more declarative, and will work with both field and getter annotations.

You have already laid out the solution 4 in your referenced blog post, as @tscho was kind to point out. Maybe defaultForType (see below) should give you the centralized solution you were looking for. Of course will will still need to differentiate between date (without time) and timestamp fields.

For future reference I will leave the summary of using your own Hibernate UserType here:

To make Hibernate give you java.util.Date instances, you can use the @Type and @TypeDef annotations to define a different mapping of your java.util.Date java types to and from the database.

See the examples in the core reference manual here.

Implement a UserType to do the actual plumbing (conversion to/from java.util.Date), named e.g. TimestampAsJavaUtilDateType
Add a @TypeDef annotation on one entity or in a package-info.java - both will be available globally for the session factory (see manual link above). You can use defaultForType to apply the type conversion on all mapped fields of type java.util.Date.
```
@TypeDef
  name = "timestampAsJavaUtilDate",
  defaultForType = java.util.Date.class, /* applied globally */
  typeClass = TimestampAsJavaUtilDateType.class
)
```

Optionally, instead of defaultForType, you can annotate your fields/getters with @Type individually:

@Entity
public class MyEntity {
   [...]
   @Type(type="timestampAsJavaUtilDate")
   private java.util.Date myDate;
   [...]
}

P.S. To suggest a totally different approach: we usually just don't compare Date objects using equals() anyway. Instead we use a utility class with methods to compare e.g. only the calendar date of two Date instances (or another resolution such as seconds), regardless of the exact implementation type. That as worked well for us.

Access-control-allow-origin with multiple domains

For IIS 7.5+ and Rewrite 2.0 you can use:

<system.webServer>
   <httpProtocol>
     <customHeaders>
         <add name="Access-Control-Allow-Headers" value="Origin, X-Requested-With, Content-Type, Accept" />
         <add name="Access-Control-Allow-Methods" value="POST,GET,OPTIONS,PUT,DELETE" />
     </customHeaders>
   </httpProtocol>
        <rewrite>            
            <outboundRules>
                <clear />                
                <rule name="AddCrossDomainHeader">
                    <match serverVariable="RESPONSE_Access_Control_Allow_Origin" pattern=".*" />
                    <conditions logicalGrouping="MatchAll" trackAllCaptures="true">
                        <add input="{HTTP_ORIGIN}" pattern="(http(s)?://((.+\.)?domain1\.com|(.+\.)?domain2\.com|(.+\.)?domain3\.com))" />
                    </conditions>
                    <action type="Rewrite" value="{C:0}" />
                </rule>           
            </outboundRules>
        </rewrite>
 </system.webServer>

Explaining the server variable RESPONSE_Access_Control_Allow_Origin portion:
In Rewrite you can use any string after RESPONSE_ and it will create the Response Header using the rest of the word as the header name (in this case Access-Control-Allow-Origin). Rewrite uses underscores "_" instead of dashes "-" (rewrite converts them to dashes)

Explaining the server variable HTTP_ORIGIN :
Similarly, in Rewrite you can grab any Request Header using HTTP_ as the prefix. Same rules with the dashes (use underscores "_" instead of dashes "-").

How do I find a stored procedure containing <text>?

I use this script. If you change your XML Comments to display as black text on a yellow background you get the effect of highlighting the text you're looking for in the xml column of the results. (Tools -> Options -> Environment -> Fonts and Colors [Display items: XML Comment]

    ---------------------------------------------
    --------------   Start  FINDTEXT   ----------
    ---------------------------------------------

    SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED 
    SET NOCOUNT ON
    GO
    DECLARE @SearchString VARCHAR(MAX) 
    SET @SearchString = 'the text you''re looking for'
    DECLARE @OverrideSearchStringWith VARCHAR(MAX) 
    --#############################################################################
    -- Use Escape chars in Brackets []  like [%] to find percent char.
    --############################################################################# 

    DECLARE @ReturnLen INT 
    SET @ReturnLen = 50;
    with    lastrun
              as (select    DEPS.OBJECT_ID
                           ,MAX(last_execution_time) as LastRun
                  from      sys.dm_exec_procedure_stats DEPS
                  group by  deps.object_id
                 )
        SELECT  OL.Type
               ,OBJECT_NAME(OL.Obj_ID) AS 'Name'
               ,LTRIM(RTRIM(REPLACE(SUBSTRING(REPLACE(OBJECT_DEFINITION(OL.Obj_ID), NCHAR(0x001F), ''), CHARINDEX(@SearchString, OBJECT_DEFINITION(OL.Obj_ID)) - @ReturnLen, @ReturnLen * 2), @SearchString, '   ***-->>' + @SearchString + '<<--***  '))) AS SourceLine
               ,CAST(REPLACE(REPLACE(REPLACE(REPLACE(CONVERT(VARCHAR(MAX), REPLACE(OBJECT_DEFINITION(OL.Obj_ID), NCHAR(0x001F), '')), '&', '(A M P)'), '<', '(L T)'), '>', '(G T)'), @SearchString, '<!-->' + @SearchString + '<-->') AS XML) AS 'Hilight Search'
               ,(SELECT [processing-instruction(A)] = REPLACE(OBJECT_DEFINITION(OL.Obj_ID), NCHAR(0x001F), '')
                FOR
                 XML PATH('')
                    ,TYPE
                ) AS 'code'
               ,Modded AS Modified
               ,LastRun as LastRun
        FROM    (SELECT CASE P.type
                          WHEN 'P' THEN 'Proc'
                          WHEN 'V' THEN 'View'
                          WHEN 'TR' THEN 'Trig'
                          ELSE 'Func'
                        END AS 'Type'
                       ,P.OBJECT_ID AS OBJ_id
                       ,P.modify_Date AS modded
                       ,LastRun.LastRun
                 FROM   sys.Objects P WITH (NOLOCK)
                        LEFT join lastrun on P.object_id = lastrun.object_id
                 WHERE  OBJECT_DEFINITION(p.OBJECT_ID) LIKE '%' + @SearchString + '%'
                        AND type IN ('P', 'V', 'TR', 'FN', 'IF', 'TF')
                     --   AND lastrun.LastRun  IS NOT null
                ) OL
    OPTION  (FAST 10)

    ---------------------------------------------
    ----------------    END     -----------------
    ---------------------------------------------
    ---------------------------------------------

How to make a whole 'div' clickable in html and css without JavaScript?

Without JS, I am doing it like this:

My HTML:

<div class="container">
  <div class="sometext">Some text here</div>
  <div class="someothertext">Some other text here</div>
  <a href="#" class="mylink">text of my link</a>
</div>

My CSS:

.container{
  position: relative;
}

.container.a{
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  text-indent: -9999px; //these two lines are to hide my actual link text.
  overflow: hidden; //these two lines are to hide my actual link text.
}

Where is SQLite database stored on disk?

SQLite is created in your python directory where you installed the python.

How can I check whether an array is null / empty?

    public boolean empty() {
    boolean isEmpty = true;
    int i = 0;
    for (int j = 0; j < array.length; j++) {
        if (array[j] != 0) {
            i++;
        }
    }
    if (i != 0) {
        isEmpty = false;
    }
    return isEmpty;
}

This is as close as I got to checking if an int array is empty. Although this will not work when the ints in the array are actually zero. It'll work for {1,2,3}, and it'll still return false if {2,0} but {0} will return true

How to click on hidden element in Selenium WebDriver?

Here is the script in Python.

You cannot click on elements in selenium that are hidden. However, you can execute JavaScript to click on the hidden element for you.

element = driver.find_element_by_id(buttonID)
driver.execute_script("$(arguments[0]).click();", element)

"The given path's format is not supported."

For me the problem was an invisible to human eye "?" Left-To-Right Embedding character.
It stuck at the beginning of the string (just before the 'D'), after I copy-pasted the path, from the windows file properties security tab.

var yourJson = System.IO.File.ReadAllText(@"D:\test\json.txt"); // Works
var yourJson = System.IO.File.ReadAllText(@"?D:\test\json.txt"); // Error

So those, identical at first glance, two lines are actually different.

Multiplying across in a numpy array

I've compared the different options for speed and found that – much to my surprise – all options (except diag) are equally fast. I personally use

A * b[:, None]

(or (A.T * b).T) because it's short.

Code to reproduce the plot:

import numpy
import perfplot


def newaxis(data):
    A, b = data
    return A * b[:, numpy.newaxis]


def none(data):
    A, b = data
    return A * b[:, None]


def double_transpose(data):
    A, b = data
    return (A.T * b).T


def double_transpose_contiguous(data):
    A, b = data
    return numpy.ascontiguousarray((A.T * b).T)


def diag_dot(data):
    A, b = data
    return numpy.dot(numpy.diag(b), A)


def einsum(data):
    A, b = data
    return numpy.einsum("ij,i->ij", A, b)


perfplot.save(
    "p.png",
    setup=lambda n: (numpy.random.rand(n, n), numpy.random.rand(n)),
    kernels=[
        newaxis,
        none,
        double_transpose,
        double_transpose_contiguous,
        diag_dot,
        einsum,
    ],
    n_range=[2 ** k for k in range(13)],
    xlabel="len(A), len(b)",
)

python setup.py uninstall

The #1 answer has problems:

Won't work on mac.
If a file is installed which includes spaces or other special characters, the xargs command will fail, and delete any files/directories which matched the individual words.
the -r in rm -rf is unnecessary and at worst could delete things you don't want to.

Instead, for unix-like:

sudo python setup.py install --record files.txt
# inspect files.txt to make sure it looks ok. Then:
tr '\n' '\0' < files.txt | xargs -0 sudo rm -f --

And for windows:

python setup.py bdist_wininst
dist/foo-1.0.win32.exe

There are also unsolvable problems with uninstalling setup.py install which won't bother you in a typical case. For a more complete answer, see this wiki page:

https://ofswiki.org/wiki/Uninstalling_setup.py_install

Database cluster and load balancing

Database clustering is a bit of an ambiguous term, some vendors consider a cluster having two or more servers share the same storage, some others call a cluster a set of replicated servers.

Replication defines the method by which a set of servers remain synchronized without having to share the storage being able to be geographically disperse, there are two main ways of going about it:

master-master (or multi-master) replication: Any server can update the database. It is usually taken care of by a different module within the database (or a whole different software running on top of them in some cases).

Downside is that it is very hard to do well, and some systems lose ACID properties when in this mode of replication.

Upside is that it is flexible and you can support the failure of any server while still having the database updated.
master-slave replication: There is only a single copy of authoritative data, which is the pushed to the slave servers.

Downside is that it is less fault tolerant, if the master dies, there are no further changes in the slaves.

Upside is that it is easier to do than multi-master and it usually preserve ACID properties.

Load balancing is a different concept, it consists distributing the queries sent to those servers so the load is as evenly distributed as possible. It is usually done at the application layer (or with a connection pool). The only direct relation between replication and load balancing is that you need some replication to be able to load balance, else you'd have a single server.

What does FETCH_HEAD in Git mean?

The FETCH_HEAD is a reference to the tip of the last fetch, whether that fetch was initiated directly using the fetch command or as part of a pull. The current value of FETCH_HEAD is stored in the .git folder in a file named, you guessed it, FETCH_HEAD.

So if I issue:

git fetch https://github.com/ryanmaxwell/Fragaria

FETCH_HEAD may contain

3cfda7cfdcf9fb78b44d991f8470df56723658d3        https://github.com/ryanmaxwell/Fragaria

If I have the remote repo configured as a remote tracking branch then I can follow my fetch with a merge of the tracking branch. If I don't I can merge the tip of the last fetch directly using FETCH_HEAD.

git merge FETCH_HEAD

How to concatenate columns in a Postgres SELECT?

CONCAT functions sometimes not work with older postgreSQL version

see what I used to solve problem without using CONCAT

 u.first_name || ' ' || u.last_name as user,

Or also you can use

 "first_name" || ' ' || "last_name" as user,

in second case I used double quotes for first_name and last_name

Hope this will be useful, thanks

With CSS, how do I make an image span the full width of the page as a background image?

If you're hoping to use background-image: url(...);, I don't think you can. However, if you want to play with layering, you can do something like this:

<img class="bg" src="..." />

And then some CSS:

.bg
{
  width: 100%;
  z-index: 0;
}

You can now layer content above the stretched image by playing with z-indexes and such. One quick note, the image can't be contained in any other elements for the width: 100%; to apply to the whole page.

Here's a quick demo if you can't rely on background-size: http://jsfiddle.net/bB3Uc/

Using Python Requests: Sessions, Cookies, and POST

I don't know how stubhub's api works, but generally it should look like this:

s = requests.Session()
data = {"login":"my_login", "password":"my_password"}
url = "http://example.net/login"
r = s.post(url, data=data)

Now your session contains cookies provided by login form. To access cookies of this session simply use

s.cookies

Any further actions like another requests will have this cookie

How to check if running as root in a bash script

In this answer, let it be clear, I presume the reader is able to read bash and POSIX shell scripts like dash.

I believe there is not much to explain here since the highly voted answers do a good job of explaining much of it.

Yet, if there is anything to explain further, don't hesitate to comment, I will do my best filling the gaps.

Optimized all-round solution for performance and reliability; all shells compatible

New solution:

# bool function to test if the user is root or not
is_user_root () { [ ${EUID:-$(id -u)} -eq 0 ]; }

Benchmark (save to file `is_user_root__benchmark`)

#+------------------------------------------------------------------------------+
#|                           is_user_root() benchmark                           |
#|                  "Bash is fast while Dash is slow in this"                   |
#|                          Language: POSIX shell script                        |
#|                        Copyright: 2020 Vlastimil Burian                      |
#|                      M@il: info[..]vlastimilburian[..]cz                     |
#|                               License: GPL 3.0                               |
#|                                 Version: 1.1                                 |
#+------------------------------------------------------------------------------+

readonly iterations=10000

# intentionally, the file does not have executable bit, nor it has no shebang
# to use it, just call the file directly with your shell interpreter like:

# bash is_user_root__benchmark
# dash is_user_root__benchmark

is_user_root () { [ ${EUID:-$(id -u)} -eq 0 ]; }

print_time   () { date +"%T.%2N"; }
print_start  () { printf '%s' 'Start  : '; print_time; }
print_finish () { printf '%s' 'Finish : '; print_time; }

printf '%s\n' '___is_user_root()___'; print_start
                   
i=1; while [ $i -lt $iterations ]; do
    is_user_root
    i=$((i + 1))
done; print_finish

Examples of use and duration:

$ dash is_user_root__benchmark 
___is_user_root()___
Start  : 03:14:04.81
Finish : 03:14:13.29

$ bash is_user_root__benchmark 
___is_user_root()___
Start  : 03:16:22.90
Finish : 03:16:23.08

Explanation

Since it is multitude times faster to read the $EUID standard bash variable, the effective user ID number, than executing id -u command to POSIX-ly find the user ID, this solution combines both into a nicely packed function. If, and only if, the $EUID is for any reason not available, the id -u command will get executed, ensuring we get the proper return value no matter the circumstances.

Why I post this solution after so many years the OP has asked

Well, if I see correctly, there does seem to be a missing piece of code above.

You see, there are many variables which have to be taken into account, and one of them is combining performance and reliability.

Portable POSIX solution + Example of usage of the above function

#!/bin/sh

# bool function to test if the user is root or not (POSIX only)
is_user_root() { [ "$(id -u)" -eq 0 ]; }

if is_user_root; then
    echo 'You are the almighty root!'
    exit 0 # implicit, here it serves the purpose to be explicit for the reader
else
    echo 'You are just an ordinary user.' >&2
    exit 1
fi

Conclusion

As much as you possibly don't like it, the Unix / Linux environment has diversified a lot. Meaning there are people who like bash so much, they don't even think of portability (POSIX shells). Others like me prefer the POSIX shells. It is nowadays a matter of personal choice and needs.

How to get the background color of an HTML element?

Simple solution

myDivObj = document.getElementById("myDivID")
let myDivObjBgColor = window.getComputedStyle(myDivObj).backgroundColor;

Now the background color is stored in the new variable.

https://jsfiddle.net/7q1dpeo9/1/

Insert picture/table in R Markdown

Several sites provide reasonable cheat sheets or HOWTOs for tables and images. Top on my list are:

Pandoc readme, specifically tables
RStudio's RMarkdown, more details in basics (including tables) and a rewrite of pandoc's markdown.

Pictures are very simple to use but do not offer the ability to adjust the image to fit the page (see Update, below). To adjust the image properties (size, resolution, colors, border, etc), you'll need some form of image editor. I find I can do everything I need with one of ImageMagick, GIMP, or InkScape, all free and open source.

To add a picture, use:

![Caption for the picture.](/path/to/image.png)

I know pandoc supports PNG and JPG, which should meet most of your needs.

You do have control over image size if you are creating it in R (e.g., a plot). This can be done either directly in the command to create the image or, even better, via options if you are using knitr (highly recommended ... check out chunk options, specifically under Plots).

I strongly recommend perusing these tutorials; markdown is very handy and has many features most people don't use on a regular basis but really like once they learn it. (SO is not necessarily the best place to ask questions that are answered very directly in these tutorials.)

Update, 2019-Aug-31

Some time ago, pandoc incorporated "link_attributes" for images (apparently in 2015, with commit jgm/pandoc#244cd56). "Resizing images" can be done directly. For example:

![unchanged image](foo.jpg)
![much-smaller image](foo.jpg){#id .class width=30 height=20px}
![half-size image](foo.jpg){#id .class width=50% height=50%}

The dimensions can be provided with no units (pixels assumed), or with "px, cm, mm, in, inch and %" (ref: https://pandoc.org/MANUAL.html, search for link_attributes).

(I'm not certain that CommonMark has implemented this, though there was a lengthy discussion.)

I keep getting this error for my simple python program: "TypeError: 'float' object cannot be interpreted as an integer"

Also possible is to fix this with np.arange() instead of range which works for float numbers:

import numpy as np
for i in np.arange(c/10):

Replace words in a string - Ruby

You can try using this way :

sentence ["Robert"] = "Roger"

Then the sentence will become :

sentence = "My name is Roger" # Robert is replaced with Roger

psql: FATAL: Ident authentication failed for user "postgres"

If you've done all this and it still doesn't work, check the expiry for that user:

Postgres password authentication fails

Java Singleton and Synchronization

public class Elvis { 
   public static final Elvis INSTANCE = new Elvis();
   private Elvis () {...}
 }

Source : Effective Java -> Item 2

It suggests to use it, if you are sure that class will always remain singleton.

How can I fix MySQL error #1064?

TL;DR

Error #1064 means that MySQL can't understand your command. To fix it:

Read the error message. It tells you exactly where in your command MySQL got confused.

Examine your command. If you use a programming language to create your command, use echo, console.log(), or its equivalent to show the entire command so you can see it.

Check the manual. By comparing against what MySQL expected at that point, the problem is often obvious.

Check for reserved words. If the error occurred on an object identifier, check that it isn't a reserved word (and, if it is, ensure that it's properly quoted).

Aaaagh!! What does #1064 mean?

Error messages may look like gobbledygook, but they're (often) incredibly informative and provide sufficient detail to pinpoint what went wrong. By understanding exactly what MySQL is telling you, you can arm yourself to fix any problem of this sort in the future.

As in many programs, MySQL errors are coded according to the type of problem that occurred. Error #1064 is a syntax error.
- What is this "syntax" of which you speak? Is it witchcraft?
  
  Whilst "syntax" is a word that many programmers only encounter in the context of computers, it is in fact borrowed from wider linguistics. It refers to sentence structure: i.e. the rules of grammar; or, in other words, the rules that define what constitutes a valid sentence within the language.
  
  For example, the following English sentence contains a syntax error (because the indefinite article "a" must always precede a noun):
  
  This sentence contains syntax error a.
- What does that have to do with MySQL?
  
  Whenever one issues a command to a computer, one of the very first things that it must do is "parse" that command in order to make sense of it. A "syntax error" means that the parser is unable to understand what is being asked because it does not constitute a valid command within the language: in other words, the command violates the grammar of the programming language.
  
  It's important to note that the computer must understand the command before it can do anything with it. Because there is a syntax error, MySQL has no idea what one is after and therefore gives up before it even looks at the database and therefore the schema or table contents are not relevant.
How do I fix it?

Obviously, one needs to determine how it is that the command violates MySQL's grammar. This may sound pretty impenetrable, but MySQL is trying really hard to help us here. All we need to do is…
- Read the message!
  
  MySQL not only tells us exactly where the parser encountered the syntax error, but also makes a suggestion for fixing it. For example, consider the following SQL command:
```
UPDATE my_table WHERE id=101 SET name='foo'
```
  That command yields the following error message:
  
  ERROR 1064 (42000): 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 'WHERE id=101 SET name='foo'' at line 1
  
  MySQL is telling us that everything seemed fine up to the word WHERE, but then a problem was encountered. In other words, it wasn't expecting to encounter WHERE at that point.
  
  Messages that say ...near '' at line... simply mean that the end of command was encountered unexpectedly: that is, something else should appear before the command ends.
- Examine the actual text of your command!
  
  Programmers often create SQL commands using a programming language. For example a php program might have a (wrong) line like this:
```
$result = $mysqli->query("UPDATE " . $tablename ."SET name='foo' WHERE id=101");
```
  If you write this this in two lines
```
$query = "UPDATE " . $tablename ."SET name='foo' WHERE id=101"
$result = $mysqli->query($query);
```
  then you can add echo $query; or var_dump($query) to see that the query actually says
```
UPDATE userSET name='foo' WHERE id=101
```
  Often you'll see your error immediately and be able to fix it.
- Obey orders!
  
  MySQL is also recommending that we "check the manual that corresponds to our MySQL version for the right syntax to use". Let's do that.
  
  I'm using MySQL v5.6, so I'll turn to that version's manual entry for an UPDATE command. The very first thing on the page is the command's grammar (this is true for every command):
```
UPDATE [LOW_PRIORITY] [IGNORE] table_reference
    SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
    [WHERE where_condition]
    [ORDER BY ...]
    [LIMIT row_count]
```
  The manual explains how to interpret this syntax under Typographical and Syntax Conventions, but for our purposes it's enough to recognise that: clauses contained within square brackets [ and ] are optional; vertical bars | indicate alternatives; and ellipses ... denote either an omission for brevity, or that the preceding clause may be repeated.
  
  We already know that the parser believed everything in our command was okay prior to the WHERE keyword, or in other words up to and including the table reference. Looking at the grammar, we see that table_reference must be followed by the SET keyword: whereas in our command it was actually followed by the WHERE keyword. This explains why the parser reports that a problem was encountered at that point.
A note of reservation

Of course, this was a simple example. However, by following the two steps outlined above (i.e. observing exactly where in the command the parser found the grammar to be violated and comparing against the manual's description of what was expected at that point), virtually every syntax error can be readily identified.

I say "virtually all", because there's a small class of problems that aren't quite so easy to spot—and that is where the parser believes that the language element encountered means one thing whereas you intend it to mean another. Take the following example:
```
UPDATE my_table SET where='foo'
```
Again, the parser does not expect to encounter WHERE at this point and so will raise a similar syntax error—but you hadn't intended for that where to be an SQL keyword: you had intended for it to identify a column for updating! However, as documented under Schema Object Names:
If an identifier contains special characters or is a reserved word, you must quote it whenever you refer to it. (Exception: A reserved word that follows a period in a qualified name must be an identifier, so it need not be quoted.) Reserved words are listed at Section 9.3, “Keywords and Reserved Words”.
```
[ deletia ]
```
The identifier quote character is the backtick (“`”):
```
mysql> SELECT * FROM `select` WHERE `select`.id > 100;
```
If the ANSI_QUOTES SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks:
```
mysql> CREATE TABLE "test" (col INT);
ERROR 1064: You have an error in your SQL syntax...
mysql> SET sql_mode='ANSI_QUOTES';
mysql> CREATE TABLE "test" (col INT);
Query OK, 0 rows affected (0.00 sec)
```

Form Submit Execute JavaScript Best Practice?

Attach an event handler to the submit event of the form. Make sure it cancels the default action.

Quirks Mode has a guide to event handlers, but you would probably be better off using a library to simplify the code and iron out the differences between browsers. All the major ones (such as YUI and jQuery) include event handling features, and there is a large collection of tiny event libraries.

Here is how you would do it in YUI 3:

<script src="http://yui.yahooapis.com/3.4.1/build/yui/yui-min.js"></script>
<script>
    YUI().use('event', function (Y) {
        Y.one('form').on('submit', function (e) {
            // Whatever else you want to do goes here
            e.preventDefault();
        });
    });
</script>

Make sure that the server will pick up the slack if the JavaScript fails for any reason.

laravel 5.3 new Auth::routes()

function call order:

(Auth)Illuminate\Support\Facades\Auth@routes (https://github.com/laravel/framework/blob/5.3/src/Illuminate/Support/Facades/Auth.php)
(App)Illuminate\Foundation\Application@auth
(Route)Illuminate\Routing\Router

it's route like this:

public function auth()
{
    // Authentication Routes...
    $this->get('login', 'Auth\AuthController@showLoginForm');
    $this->post('login', 'Auth\AuthController@login');
    $this->get('logout', 'Auth\AuthController@logout');
    // Registration Routes...
    $this->get('register', 'Auth\AuthController@showRegistrationForm');
    $this->post('register', 'Auth\AuthController@register');
    // Password Reset Routes...
    $this->get('password/reset/{token?}', 'Auth\PasswordController@showResetForm');
    $this->post('password/email', 'Auth\PasswordController@sendResetLinkEmail');
    $this->post('password/reset', 'Auth\PasswordController@reset');
}

select and echo a single field from mysql db using PHP

Read the manual, it covers it very well: http://php.net/manual/en/function.mysql-query.php

Usually you do something like this:

while ($row = mysql_fetch_assoc($result)) {
  echo $row['firstname'];
  echo $row['lastname'];
  echo $row['address'];
  echo $row['age'];
}

Merging Cells in Excel using C#

Excel.Application xl = new Excel.ApplicationClass();

Excel.Workbook wb = xl.Workbooks.Add(Excel.XlWBATemplate.xlWBATWorkshe et);

Excel.Worksheet ws = (Excel.Worksheet)wb.ActiveSheet;

ws.Cells[1,1] = "Testing";

Excel.Range range = ws.get_Range(ws.Cells[1,1],ws.Cells[1,2]);

range.Merge(true);

range.Interior.ColorIndex =36;

xl.Visible =true;

insert data into database with codeigniter

Just insert $this->load->database(); in your model:

function order_summary_insert($data){
    $this->load->database();
    $this->db->insert('Customer_Orders',$data);
}

Python Iterate Dictionary by Index

I wanted to know (idx, key, value) for a python OrderedDict today (mapping of SKUs to quantities in order of the way they should appear on a receipt). The answers here were all bummers.

In python 3, at least, this way works and and makes sense.

In [1]: from collections import OrderedDict
   ...: od = OrderedDict()
   ...: od['a']='spam'
   ...: od['b']='ham'
   ...: od['c']='eggs'
   ...: 
   ...: for i,(k,v) in enumerate(od.items()):
   ...:    print('%d,%s,%s'%(i,k,v))
   ...: 
0,a,spam
1,b,ham
2,c,eggs

How do I make Java register a string input with spaces?

Instead of

Scanner in = new Scanner(System.in);
String question;
question = in.next();

Type in

Scanner in = new Scanner(System.in);
String question;
question = in.nextLine();

This should be able to take spaces as input.

Text not wrapping in p tag

EASY

p{
    word-wrap: break-word;
}

trace a particular IP and port

tcptraceroute   xx.xx.xx.xx 9100

if you didn't find it you can install it

yum -y install tcptraceroute

aptitude -y install tcptraceroute

openpyxl - adjust column width size

This is a dirty fix. But openpyxl actually supports auto_fit. But there is no method to access the property.

import openpyxl
from openpyxl.utils import get_column_letter

wb = openpyxl.load_workbook("Example.xslx")
ws = wb["Sheet1"]
for i in range(1, ws.max_column+1):
    ws.column_dimensions[get_column_letter(i)].bestFit = True
    ws.column_dimensions[get_column_letter(i)].auto_size = True

How to setup FTP on xampp

XAMPP for linux and mac comes with ProFTPD. Make sure to start the service from XAMPP control panel -> manage servers.

Further complete instructions can be found at localhost XAMPP dashboard -> How-to guides -> Configure FTP Access. I have pasted them below :

Open a new Linux terminal and ensure you are logged in as root.
Create a new group named ftp. This group will contain those user accounts allowed to upload files via FTP.

groupadd ftp

Add your account (in this example, susan) to the new group. Add other users if needed.

usermod -a -G ftp susan

Change the ownership and permissions of the htdocs/ subdirectory of the XAMPP installation directory (typically, /opt/lampp) so that it is writable by the the new ftp group.

cd /opt/lampp chown root.ftp htdocs chmod 775 htdocs

Ensure that proFTPD is running in the XAMPP control panel.

You can now transfer files to the XAMPP server using the steps below:

Start an FTP client like winSCP or FileZilla and enter connection details as below.

If you’re connecting to the server from the same system, use "127.0.0.1" as the host address. If you’re connecting from a different system, use the network hostname or IP address of the XAMPP server.

Use "21" as the port.

Enter your Linux username and password as your FTP credentials.

Your FTP client should now connect to the server and enter the /opt/lampp/htdocs/ directory, which is the default Web server document root.

Transfer the file from your home directory to the server using normal FTP transfer conventions. If you’re using a graphical FTP client, you can usually drag and drop the file from one directory to the other. If you’re using a command-line FTP client, you can use the FTP PUT command.

Once the file is successfully transferred, you should be able to see it in action.

BULK INSERT with identity (auto-increment) column

My solution is to add the ID field as the LAST field in the table, thus bulk insert ignores it and it gets automatic values. Clean and simple ...

For instance, if inserting into a temp table:

CREATE TABLE #TempTable 
(field1 varchar(max), field2 varchar(max), ... 
ROW_ID int IDENTITY(1,1) NOT NULL)

Note that the ROW_ID field MUST always be specified as LAST field!

How do you install Boost on MacOS?

You can get the latest version of Boost by using Homebrew.

brew install boost.

Altering a column to be nullable

Oracle

ALTER TABLE Merchant_Pending_Functions MODIFY([column] NOT NULL);

OpenVPN failed connection / All TAP-Win32 adapters on this system are currently in use

I found a solution to this. It's bloody witchcraft, but it works.

When you install the client, open Control Panel > Network Connections.

You'll see a disabled network connection that was added by the TAP installer (Local Area Connection 3 or some such).

Right Click it, click Enable.

The device will not reset itself to enabled, but that's ok; try connecting w/ the client again. It'll work.

OSError: [Errno 2] No such file or directory while using python subprocess in Django

Use shell=True if you're passing a string to subprocess.call.

From docs:

If passing a single string, either shell must be True or else the string must simply name the program to be executed without specifying any arguments.

subprocess.call(crop, shell=True)

or:

import shlex
subprocess.call(shlex.split(crop))

Cannot lower case button text in android studio

<style name="AppTheme" parent="AppBaseTheme">
    <item name="android:buttonStyle">@style/Button</item>
</style>

<style name="Button" parent="Widget.AppCompat.Button">
    <item name="android:textAllCaps">false</item>
</style>

How to do a GitHub pull request

To learn how to make a pull request I just followed two separate help pages on Github (linked below as bullet points). The following command line commands are for Part 1. Part 2, the actual pull request, is done entirely on Github's website.

$ git clone https://github.com/tim-peterson/dwolla-php.git
$ cd dwolla-php
$ git remote add upstream https://github.com/Dwolla/dwolla-php.git
$ git fetch upstream
// make your changes to this newly cloned, local repo 
$ git add .
$ git commit -m '1st commit to dwolla'
$ git push origin master

Part 1: fork someone's repo: https://help.github.com/articles/fork-a-repo
1. click the 'fork' button on the repo you want to contribute to, in this case: Dwolla's PHP repo (Dwolla/dwolla-php)
2. get the URL for your newly created fork, in this case: https://github.com/tim-peterson/dwolla-php.git (tim-peterson/dwolla-php)
3. type the git clone->cd dwolla-php->git remote->git fetch sequence above to clone your fork somewhere in your computer (i.e., "copy/paste" it to, in this case: third_party TimPeterson$) and sync it with the master repo (Dwolla/dwolla-php)
4. make your changes to your local repo
5. type the git add->git commit->git push sequence above to push your changes to the remote repo, i.e., your fork on Github (tim-peterson/dwolla-php)
Part 2: make pull-request: https://help.github.com/articles/using-pull-requests
1. go to your fork's webpage on Github (https://github.com/tim-peterson/dwolla-php)
2. click 'pull-request' button
3. give pull-request a name, fill in details of what changes you made, click submit button.
4. you're done!!

How to compare the contents of two string objects in PowerShell

You want to do $arrayOfString[0].Title -eq $myPbiject.item(0).Title

-match is for regex matching ( the second argument is a regex )

Rotating videos with FFmpeg

An additional solution with a different approach from the last mentioned solutions, is to check if your camera driver support the v4l2 camera controls (which is very common).
In the terminal just type:

v4l2-ctl -L

If your camera driver supports the v4l2 camera controls, you should get something like this (the list below depends on the controls that your camera driver supports):

               contrast (int)    : min=0 max=255 step=1 default=0 value=0 flags=slider
             saturation (int)    : min=0 max=255 step=1 default=64 value=64 flags=slider
                    hue (int)    : min=0 max=359 step=1 default=0 value=0 flags=slider
white_balance_automatic (bool)   : default=1 value=1 flags=update
            red_balance (int)    : min=0 max=4095 step=1 default=0 value=128 flags=inactive, slider
           blue_balance (int)    : min=0 max=4095 step=1 default=0 value=128 flags=inactive, slider
               exposure (int)    : min=0 max=65535 step=1 default=0 value=885 flags=inactive, volatile
         gain_automatic (bool)   : default=1 value=1 flags=update
                   gain (int)    : min=0 max=1023 step=1 default=0 value=32 flags=inactive, volatile
        horizontal_flip (bool)   : default=0 value=0
          vertical_flip (bool)   : default=0 value=0

And if you are lucky it supports horizontal_flip and vertical_flip.
Then all you need to do is to set the horizontal_flip by:

v4l2-ctl --set-ctrl horizontal_flip=1

or the vertical_flip by:

v4l2-ctl --set-ctrl vertical_flip=1

and then you can call your video device to capture a new video (see example below), and the video will be rotated/flipped.

ffmpeg -f v4l2 -video_size 640x480 -i /dev/video0 -vcodec libx264 -f mpegts input.mp4

Of-course that if you need to process an already existing video, than this method is not the solution you are looking for.

The advantage in this approach is that we flip the image in the sensor level, so the sensor of the driver already gives us the image flipped, and that's saves the application (like FFmpeg) any further and unnecessary processing.

WebSockets protocol vs HTTP

You seem to assume that WebSocket is a replacement for HTTP. It is not. It's an extension.

The main use-case of WebSockets are Javascript applications which run in the web browser and receive real-time data from a server. Games are a good example.

Before WebSockets, the only method for Javascript applications to interact with a server was through XmlHttpRequest. But these have a major disadvantage: The server can't send data unless the client has explicitly requested it.

But the new WebSocket feature allows the server to send data whenever it wants. This allows to implement browser-based games with a much lower latency and without having to use ugly hacks like AJAX long-polling or browser plugins.

So why not use normal HTTP with streamed requests and responses

In a comment to another answer you suggested to just stream the client request and response body asynchronously.

In fact, WebSockets are basically that. An attempt to open a WebSocket connection from the client looks like a HTTP request at first, but a special directive in the header (Upgrade: websocket) tells the server to start communicating in this asynchronous mode. First drafts of the WebSocket protocol weren't much more than that and some handshaking to ensure that the server actually understands that the client wants to communicate asynchronously. But then it was realized that proxy servers would be confused by that, because they are used to the usual request/response model of HTTP. A potential attack scenario against proxy servers was discovered. To prevent this it was necessary to make WebSocket traffic look unlike any normal HTTP traffic. That's why the masking keys were introduced in the final version of the protocol.

What is href="#" and why is it used?

It's a link that links to nowhere essentially (it just adds "#" onto the URL). It's used for a number of different reasons. For instance, if you're using some sort of JavaScript/jQuery and don't want the actual HTML to link anywhere.

It's also used for page anchors, which is used to redirect to a different part of the page.

difference between throw and throw new Exception()

Most important difference is that second expression erases type of exception. And exception type plays vital role in catching exceptions:

public void MyMethod ()
{
    // both can throw IOException
    try { foo(); } catch { throw; }
    try { bar(); } catch(E) {throw new Exception(E.message); }
}

(...)

try {
    MyMethod ();
} catch (IOException ex) {
    Console.WriteLine ("Error with I/O"); // [1]
} catch (Exception ex) {
    Console.WriteLine ("Other error");    // [2]
}

If foo() throws IOException, [1] catch block will catch exception. But when bar() throws IOException, it will be converted to plain Exception ant won't be caught by [1] catch block.

Numpy - Replace a number with NaN

A[A==NDV]=numpy.nan

A==NDV will produce a boolean array that can be used as an index for A

error: use of deleted function

The error message clearly says that the default constructor has been deleted implicitly. It even says why: the class contains a non-static, const variable, which would not be initialized by the default ctor.

class X {
    const int x;
};

Since X::x is const, it must be initialized -- but a default ctor wouldn't normally initialize it (because it's a POD type). Therefore, to get a default ctor, you need to define one yourself (and it must initialize x). You can get the same kind of situation with a member that's a reference:

class X { 
    whatever &x;
};

It's probably worth noting that both of these will also disable implicit creation of an assignment operator as well, for essentially the same reason. The implicit assignment operator normally does members-wise assignment, but with a const member or reference member, it can't do that because the member can't be assigned. To make assignment work, you need to write your own assignment operator.

This is why a const member should typically be static -- when you do an assignment, you can't assign the const member anyway. In a typical case all your instances are going to have the same value so they might as well share access to a single variable instead of having lots of copies of a variable that will all have the same value.

It is possible, of course, to create instances with different values though -- you (for example) pass a value when you create the object, so two different objects can have two different values. If, however, you try to do something like swapping them, the const member will retain its original value instead of being swapped.

Best way to randomize an array with .NET

Just thinking off the top of my head, you could do this:

public string[] Randomize(string[] input)
{
  List<string> inputList = input.ToList();
  string[] output = new string[input.Length];
  Random randomizer = new Random();
  int i = 0;

  while (inputList.Count > 0)
  {
    int index = r.Next(inputList.Count);
    output[i++] = inputList[index];
    inputList.RemoveAt(index);
  }

  return (output);
}

Html.DropDownList - Disabled/Readonly

Try this

Html.DropDownList("Types", Model.Types, new { @disabled = "disabled" })

css transform, jagged edges in chrome

Try 3d transform. This works like a charm!

/* Due to a bug in the anti-liasing*/
-webkit-transform-style: preserve-3d; 
-webkit-transform: rotateZ(2deg);

How do I find the absolute position of an element using jQuery?

Note that $(element).offset() tells you the position of an element relative to the document. This works great in most circumstances, but in the case of position:fixed you can get unexpected results.

If your document is longer than the viewport and you have scrolled vertically toward the bottom of the document, then your position:fixed element's offset() value will be greater than the expected value by the amount you have scrolled.

If you are looking for a value relative to the viewport (window), rather than the document on a position:fixed element, you can subtract the document's scrollTop() value from the fixed element's offset().top value. Example: $("#el").offset().top - $(document).scrollTop()

If the position:fixed element's offset parent is the document, you want to read parseInt($.css('top')) instead.

How to install a gem or update RubyGems if it fails with a permissions error

There are two routes: Use either rbenv or RVM. There are recipes for both below. Before you do, you probably want to turn off the installation of local documents for gems.

echo "gem: --no-ri --no-rdoc" >> ~/.gemrc

Then:

install rbenv

install ruby-build

run:

rbenv install 2.1.2 (or whatever version you prefer)
rbenv global 2.1.2
gem update --system

This installs an up-to-date version of the gem system in your local directories. That means you don't interfere with the system configuration. If you're asking this question, you shouldn't be messing with system security, and you'll spend longer understanding what issues you may run into, than just having an easy way to avoid the problem you started with. Learn InfoSec later, when you know more about the operating system and programming.

For an alternative use 'RVM' instead: To install rvm run:

rvm install 2.1.2
rvm use 2.1.2
gem update --system

This has the same result, you end up with a local Ruby and Gem system that doesn't interfere with the system versions. There is no need for Homebrew, or over-riding system libs, etc.

Java: Get month Integer from Date

tl;dr

myUtilDate.toInstant()                          // Convert from legacy class to modern. `Instant` is a point on the timeline in UTC.
          .atZone(                              // Adjust from UTC to a particular time zone to determine date. Renders a `ZonedDateTime` object. 
              ZoneId.of( "America/Montreal" )   // Better to specify desired/expected zone explicitly than rely implicitly on the JVM’s current default time zone.
          )                                     // Returns a `ZonedDateTime` object.
          .getMonthValue()                      // Extract a month number. Returns a `int` number.

`java.time` Details

The Answer by Ortomala Lokni for using java.time is correct. And you should be using java.time as it is a gigantic improvement over the old java.util.Date/.Calendar classes. See the Oracle Tutorial on java.time.

I'll add some code showing how to use java.time without regard to java.util.Date, for when you are starting out with fresh code.

Using java.time in a nutshell… An Instant is a moment on the timeline in UTC. Apply a time zone (ZoneId) to get a ZonedDateTime.

The Month class is a sophisticated enum to represent a month in general. That enum has handy methods such as getting a localized name. And rest assured that the month number in java.time is a sane one, 1-12, not the zero-based nonsense (0-11) found in java.util.Date/.Calendar.

To get the current date-time, time zone is crucial. At any moment the date is not the same around the world. Therefore the month is not the same around the world if near the ending/beginning of the month.

ZoneId zoneId = ZoneId.of( "America/Montreal" );  // Or 'ZoneOffset.UTC'.
ZonedDateTime now = ZonedDateTime.now( zoneId );
Month month = now.getMonth(); 
int monthNumber = month.getValue(); // Answer to the Question.
String monthName = month.getDisplayName( TextStyle.FULL , Locale.CANADA_FRENCH );

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

Java SE 8, Java SE 9, Java SE 10, and later
- Built-in.
- Part of the standard Java API with a bundled implementation.
- Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
- Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
- Later versions of Android bundle implementations of the java.time classes.
- For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Do I really need to encode '&' as '&'?

if & is used in html then you should escape it

If & is used in javascript strings e.g. an alert('This & that'); or document.href you don't need to use it.

If you're using document.write then you should use it e.g. document.write(<p>this & that</p>)

How can I extract a number from a string in JavaScript?

This answer will cover most of the scenario. I can across this situation when user try to copy paste the phone number

  $('#help_number').keyup(function(){
    $(this).val().match(/\d+/g).join("")
  });

Explanation:

str= "34%^gd 5-67 6-6ds"

str.match(/\d+/g)

It will give a array of string as output >> ["34", "56766"]

str.match(/\d+/g).join("")

join will convert and concatenate that array data into single string

output >> "3456766"

In my example I need the output as 209-356-6788 so I used replace

  $('#help_number').keyup(function(){
    $(this).val($(this).val().match(/\d+/g).join("").replace(/(\d{3})\-?(\d{3})\-?(\d{4})/,'$1-$2-$3'))
  });

How to Bootstrap navbar static to fixed on scroll?

set max-height as you need:

.navbar-fixed-top 
.navbar-collapse, 
.navbar-fixed-bottom 
.navbar-collapse {
    max-height: 700px;
}

Why does 'git commit' not save my changes?

I find this problem appearing when I've done a git add . in a subdirectory below where my .gitignore file lives (the home directory of my repository, so to speak). Try changing directories to your uppermost directory and running git add . followed by git commit -m "my commit message".

Update rows in one table with data from another table based on one column in each being equal

merge into t2 t2 
using (select * from t1) t1
on (t2.user_id = t1.user_id)
when matched then update
set
   t2.c1 = t1.c1
,  t2.c2 = t1.c2

How to pass IEnumerable list to controller in MVC including checkbox state?

Use a list instead and replace your foreach loop with a for loop:

@model IList<BlockedIPViewModel>

@using (Html.BeginForm()) 
{ 
    @Html.AntiForgeryToken()

    @for (var i = 0; i < Model.Count; i++) 
    {
        <tr>
            <td>
                @Html.HiddenFor(x => x[i].IP)           
                @Html.CheckBoxFor(x => x[i].Checked)
            </td>
            <td>
                @Html.DisplayFor(x => x[i].IP)
            </td>
        </tr>
    }
    <div>
        <input type="submit" value="Unblock IPs" />
    </div>
}

Alternatively you could use an editor template:

@model IEnumerable<BlockedIPViewModel>

@using (Html.BeginForm()) 
{ 
    @Html.AntiForgeryToken()
    @Html.EditorForModel()   
    <div>
        <input type="submit" value="Unblock IPs" />
    </div>
}

and then define the template ~/Views/Shared/EditorTemplates/BlockedIPViewModel.cshtml which will automatically be rendered for each element of the collection:

@model BlockedIPViewModel
<tr>
    <td>
        @Html.HiddenFor(x => x.IP)
        @Html.CheckBoxFor(x => x.Checked)
    </td>
    <td>
        @Html.DisplayFor(x => x.IP)
    </td>
</tr>

The reason you were getting null in your controller is because you didn't respect the naming convention for your input fields that the default model binder expects to successfully bind to a list. I invite you to read the following article.

Once you have read it, look at the generated HTML (and more specifically the names of the input fields) with my example and yours. Then compare and you will understand why yours doesn't work.

Wrapping a react-router Link in an html button

Many of the solutions have focused on complicating things.

Using withRouter is a really long solution for something as simple as a button that links to somewhere else in the App.

If you are going for S.P.A. (single page application), the easiest answer I have found is to use with the button's equivalent className.

This ensures you are maintaining shared state / context without reloading your entire app as is done with

import { NavLink } from 'react-router-dom'; // 14.6K (gzipped: 5.2 K)

// Where link.{something} is the imported data
<NavLink className={`bx--btn bx--btn--primary ${link.className}`} to={link.href} activeClassName={'active'}>
    {link.label}
</NavLink>

// Simplified version:
<NavLink className={'bx--btn bx--btn--primary'} to={'/myLocalPath'}>
    Button without using withRouter
</NavLink>

Display A Popup Only Once Per User

This example uses jquery-cookie

Check if the cookie exists and has not expired - if either of those fails, then show the popup and set the cookie (Semi pseudo code):

if($.cookie('popup') != 'seen'){
    $.cookie('popup', 'seen', { expires: 365, path: '/' }); // Set it to last a year, for example.
    $j("#popup").delay(2000).fadeIn();
    $j('#popup-close').click(function(e) // You are clicking the close button
        {
        $j('#popup').fadeOut(); // Now the pop up is hiden.
    });
    $j('#popup').click(function(e) 
        {
        $j('#popup').fadeOut(); 
    });
};

How can you zip or unzip from the script using ONLY Windows' built-in capabilities?

It isn't exactly a ZIP, but the only way to compress a file using Windows tools is:

makecab <source> <dest>.cab

To decompress:

expand <source>.cab <dest>

Advanced example (from ss64.com):

Create a self extracting archive containing movie.mov:
C:\> makecab movie.mov "temp.cab"
C:\> copy /b "%windir%\system32\extrac32.exe"+"temp.cab" "movie.exe"
C:\> del /q /f "temp.cab"

More information: makecab, expand, makecab advanced uses

Implementation difference between Aggregation and Composition in Java

A simple Composition program

public class Person {
    private double salary;
    private String name;
    private Birthday bday;

    public Person(int y,int m,int d,String name){
        bday=new Birthday(y, m, d);
        this.name=name;
    }


    public double getSalary() {
        return salary;
    }

    public String getName() {
        return name;
    }

    public Birthday getBday() {
        return bday;
    }

    ///////////////////////////////inner class///////////////////////
    private class Birthday{
        int year,month,day;

        public Birthday(int y,int m,int d){
            year=y;
            month=m;
            day=d;
        }

        public String toString(){
           return String.format("%s-%s-%s", year,month,day);

        }
    }

    //////////////////////////////////////////////////////////////////

}
public class CompositionTst {

    public static void main(String[] args) {
        // TODO code application logic here
        Person person=new Person(2001, 11, 29, "Thilina");
        System.out.println("Name : "+person.getName());
        System.out.println("Birthday : "+person.getBday());

        //The below object cannot be created. A bithday cannot exixts without a Person 
        //Birthday bday=new Birthday(1988,11,10);

    }
}

JavaFX - create custom button with image

You just need to create your own class inherited from parent. Place an ImageView on that, and on the mousedown and mouse up events just change the images of the ImageView.

public class ImageButton extends Parent {

    private static final Image NORMAL_IMAGE = ...;
    private static final Image PRESSED_IMAGE = ...;

    private final ImageView iv;

    public ImageButton() {
        this.iv = new ImageView(NORMAL_IMAGE);
        this.getChildren().add(this.iv);

        this.iv.setOnMousePressed(new EventHandler<MouseEvent>() {

            public void handle(MouseEvent evt) {
                iv.setImage(PRESSED_IMAGE);
            }

        });

        // TODO other event handlers like mouse up

    } 

}

Loop through a Map with JSTL

Like this:

<c:forEach var="entry" items="${myMap}">
  Key: <c:out value="${entry.key}"/>
  Value: <c:out value="${entry.value}"/>
</c:forEach>

How do I check if a variable exists?

Using try/except is the best way to test for a variable's existence. But there's almost certainly a better way of doing whatever it is you're doing than setting/testing global variables.

For example, if you want to initialize a module-level variable the first time you call some function, you're better off with code something like this:

my_variable = None

def InitMyVariable():
  global my_variable
  if my_variable is None:
    my_variable = ...

How to run multiple sites on one apache instance

Yes with Virtual Host you can have as many parallel programs as you want:

Open

/etc/httpd/conf/httpd.conf

Listen 81
Listen 82
Listen 83

<VirtualHost *:81>
    ServerAdmin [email protected]
    DocumentRoot /var/www/site1/html
    ServerName site1.com
    ErrorLog logs/site1-error_log
    CustomLog logs/site1-access_log common
    ScriptAlias /cgi-bin/ "/var/www/site1/cgi-bin/"
</VirtualHost>

<VirtualHost *:82>
    ServerAdmin [email protected]
    DocumentRoot /var/www/site2/html
    ServerName site2.com
    ErrorLog logs/site2-error_log
    CustomLog logs/site2-access_log common
    ScriptAlias /cgi-bin/ "/var/www/site2/cgi-bin/"
</VirtualHost>

<VirtualHost *:83>
    ServerAdmin [email protected]
    DocumentRoot /var/www/site3/html
    ServerName site3.com
    ErrorLog logs/site3-error_log
    CustomLog logs/site3-access_log common
    ScriptAlias /cgi-bin/ "/var/www/site3/cgi-bin/"
</VirtualHost>

Restart apache

service httpd restart

You can now refer Site1 :

http://<ip-address>:81/ 
http://<ip-address>:81/cgi-bin/

Site2 :

http://<ip-address>:82/
http://<ip-address>:82/cgi-bin/

Site3 :

http://<ip-address>:83/ 
http://<ip-address>:83/cgi-bin/

If path is not hardcoded in any script then your websites should work seamlessly.

Configure apache to listen on port other than 80

If you need apache Listen port other than 80, you should add next file under ubuntu

"/etc/apache2/ports.conf"

the list of Listen ports

Listen 80
Listen 81
Listen 82

After you have to go on your Virtual hosts conf file and define next

<VirtualHost *:80>
  #...v host 1
</VirtualHost>


<VirtualHost *:81>
  #...host 2
</VirtualHost>


<VirtualHost *:82>
  #...host 3
</VirtualHost>

Service has zero application (non-infrastructure) endpoints

I had the same problem. Everything works in VS2010 but when I run the same project in VS2008 I get the mentioned exception.

What I did in my VS2008 project to make it work was adding a call to the AddServiceEndpoint member of my ServiceHost object.

Here is my code snippet:

Uri baseAddress = new Uri("http://localhost:8195/v2/SystemCallbackListener");

ServiceHost host = new ServiceHost(typeof(SystemCallbackListenerImpl), baseAddress);

host.AddServiceEndpoint(typeof(CsfServiceReference.SystemCallbackListener),
                        new BasicHttpBinding(),
                        baseAddress);
host.Open();

I didn't modify the app.config file. But I guess the service endpoint could also have been added in the .config file.

What is the difference between a Docker image and a container?

While it's simplest to think of a container as a running image, this isn't quite accurate.

An image is really a template that can be turned into a container. To turn an image into a container, the Docker engine takes the image, adds a read-write filesystem on top and initialises various settings including network ports, container name, ID and resource limits. A running container has a currently executing process, but a container can also be stopped (or exited in Docker's terminology). An exited container is not the same as an image, as it can be restarted and will retain its settings and any filesystem changes.

What is newline character -- '\n'

Try this:

$ sed -e $'s/\n/\n\n/g' states

Getting key with maximum value in dictionary?

You can use:

max(d, key = d.get) 
# which is equivalent to 
max(d, key = lambda k : d.get(k))

To return the key, value pair use:

max(d.items(), key = lambda k : k[1])

How to increase font size in a plot in R?

You want something like the cex=1.5 argument to scale fonts 150 percent. But do see help(par) as there are also cex.lab, cex.axis, ...

In JavaScript, why is "0" equal to false, but when tested by 'if' it is not false by itself?

This is because JavaScript uses type coercion in Boolean contexts and your code

if ("0")

will be coerced to true in boolean contexts.

There are other truthy values in Javascript which will be coerced to true in boolean contexts, and thus execute the if block are:-

if (true)
if ({})
if ([])
if (42)
if ("0")
if ("false")
if (new Date())
if (-42)
if (12n)
if (3.14)
if (-3.14)
if (Infinity)
if (-Infinity)

Angular2: Cannot read property 'name' of undefined

You just needed to read a little further and you would have been introduced to the *ngIf structural directive.

selectedHero.name doesn't exist yet because the user has yet to select a hero so it returns undefined.

<div *ngIf="selectedHero">
  <h2>{{selectedHero.name}} details!</h2>
  <div><label>id: </label>{{selectedHero.id}}</div>
  <div>
    <label>name: </label>
    <input [(ngModel)]="selectedHero.name" placeholder="name"/>
  </div>
</div>

The *ngIf directive keeps selectedHero off the DOM until it is selected and therefore becomes truthy.

This document helped me understand structural directives.

How to change font-size of a tag using inline css?

Strange it doesn't change, as inline styles are most specific, if style sheet has !important declared, it wont over ride, try this and see

<span style="font-size: 11px !important; color: #aaaaaa;">Hello</span>

Range with step of type float

This is what I would use:

numbers = [float(x)/10 for x in range(10)]

rather than:

numbers = [x*0.1 for x in range(10)]
that would return :
[0.0, 0.1, 0.2, 0.30000000000000004, 0.4, 0.5, 0.6000000000000001, 0.7000000000000001, 0.8, 0.9]

hope it helps.

How to set index.html as root file in Nginx?

For me, the try_files directive in the (currently most voted) answer https://stackoverflow.com/a/11957896/608359 led to rewrite cycles,

*173 rewrite or internal redirection cycle while internally redirecting

I had better luck with the index directive. Note that I used a forward slash before the name, which might or might not be what you want.

server {
  listen 443 ssl;
  server_name example.com;

  root /home/dclo/example;
  index /index.html;
  error_page 404 /index.html;

  # ... ssl configuration
}

In this case, I wanted all paths to lead to /index.html, including when returning a 404.

How to get height and width of device display in angular2 using typescript?

I found the solution. The answer is very simple. write the below code in your constructor.

import { Component, OnInit, OnDestroy, Input } from "@angular/core";
// Import this, and write at the top of your .ts file
import { HostListener } from "@angular/core";

@Component({
  selector: "app-login",
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.css']
})

export class LoginComponent implements OnInit, OnDestroy {
    // Declare height and width variables
    scrHeight:any;
    scrWidth:any;

    @HostListener('window:resize', ['$event'])
    getScreenSize(event?) {
          this.scrHeight = window.innerHeight;
          this.scrWidth = window.innerWidth;
          console.log(this.scrHeight, this.scrWidth);
    }

    // Constructor
    constructor() {
        this.getScreenSize();
    }


}

====== Working Code (Another) ======

export class Dashboard  {
 mobHeight: any;
 mobWidth: any;
     constructor(private router:Router, private http: Http){
        this.mobHeight = (window.screen.height) + "px";
        this.mobWidth = (window.screen.width) + "px";
          console.log(this.mobHeight);
          console.log(this.mobWidth)
     }
}

Create a asmx web service in C# using visual studio 2013

Create Empty ASP.NET Project
Add Web Service(asmx) to your project

Generating random numbers with Swift

===== Swift 4.2 / Xcode 10 =====

let randomIntFrom0To10 = Int.random(in: 1..<10)
let randomFloat = Float.random(in: 0..<1)

// if you want to get a random element in an array
let greetings = ["hey", "hi", "hello", "hola"]
greetings.randomElement()

Under the hood Swift uses arc4random_buf to get job done.

===== Swift 4.1 / Xcode 9 =====

arc4random() returns a random number in the range of 0 to 4 294 967 295

drand48() returns a random number in the range of 0.0 to 1.0

arc4random_uniform(N) returns a random number in the range of 0 to N - 1

Examples:

arc4random() // => UInt32 = 2739058784
arc4random() // => UInt32 = 2672503239
arc4random() // => UInt32 = 3990537167
arc4random() // => UInt32 = 2516511476
arc4random() // => UInt32 = 3959558840

drand48() // => Double = 0.88642843322303122
drand48() // => Double = 0.015582849408328769
drand48() // => Double = 0.58409022031727176
drand48() // => Double = 0.15936862653180484
drand48() // => Double = 0.38371587480719427

arc4random_uniform(3) // => UInt32 = 0
arc4random_uniform(3) // => UInt32 = 1
arc4random_uniform(3) // => UInt32 = 0
arc4random_uniform(3) // => UInt32 = 1
arc4random_uniform(3) // => UInt32 = 2

arc4random_uniform() is recommended over constructions like arc4random() % upper_bound as it avoids "modulo bias" when the upper bound is not a power of two.

MySQL "NOT IN" query

Be carefull NOT IN is not an alias for <> ANY, but for <> ALL!

http://dev.mysql.com/doc/refman/5.0/en/any-in-some-subqueries.html

SELECT c FROM t1 LEFT JOIN t2 USING (c) WHERE t2.c IS NULL

cant' be replaced by

SELECT c FROM t1 WHERE c NOT IN (SELECT c FROM t2)

You must use

SELECT c FROM t1 WHERE c <> ANY (SELECT c FROM t2)

JOptionPane YES/No Options Confirm Dialog Box Issue

You need to look at the return value of the call to showConfirmDialog. I.E.:

int dialogResult = JOptionPane.showConfirmDialog (null, "Would You Like to Save your Previous Note First?","Warning",dialogButton);
if(dialogResult == JOptionPane.YES_OPTION){
  // Saving code here
}

You were testing against dialogButton, which you were using to set the buttons that should be displayed by the dialog, and this variable was never updated - so dialogButton would never have been anything other than JOptionPane.YES_NO_OPTION.

Per the Javadoc for showConfirmDialog:

Returns: an integer indicating the option selected by the user

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.....

Clear History and Reload Page on Login/Logout Using Ionic Framework

I needed to reload the state to make scrollbars work. They did not work when coming through another state - 'registration'. If the app was force closed after registration and opened again, i.e. it went directly to 'home' state, the scrollbars worked. None of the above solutions worked.

When after registration, I replaced:

$state.go("home");

with

window.location = "index.html";

The app reloaded, and the scrollbars worked.

Select and display only duplicate records in MySQL

This works the fastest for me

SELECT
    primary_key
FROM
    table_name
WHERE
    primary_key NOT IN (
        SELECT
            primary_key
        FROM
            table_name
        GROUP BY
            column_name
        HAVING
            COUNT(*) = 1
    );

Disable clipboard prompt in Excel VBA on workbook close

I have hit this problem in the past - from the look of it if you don't actually need the clipboard at the point that you exit, so you can use the same simple solution I had. Just clear the clipboard. :)

ActiveCell.Copy

How to remove all duplicate items from a list

You can do this like that:

x = list(set(x))

Example: if you do something like that:

x = [1,2,3,4,5,6,7,8,9,10,2,1,6,31,20]
x = list(set(x))
x

you will see the following result:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 31]

There is only one thing you should think of: the resulting list will not be ordered as the original one (will lose the order in the process).

How to use background thread in swift?

Since the OP question has already been answered above I just want to add some speed considerations:

I don't recommend running tasks with the .background thread priority especially on the iPhone X where the task seems to be allocated on the low power cores.

Here is some real data from a computationally intensive function that reads from an XML file (with buffering) and performs data interpolation:

Device name / .background / .utility / .default / .userInitiated / .userInteractive

iPhone X: 18.7s / 6.3s / 1.8s / 1.8s / 1.8s
iPhone 7: 4.6s / 3.1s / 3.0s / 2.8s / 2.6s
iPhone 5s: 7.3s / 6.1s / 4.0s / 4.0s / 3.8s

Note that the data set is not the same for all devices. It's the biggest on the iPhone X and the smallest on the iPhone 5s.

Reading JSON from a file?

In python 3, we can use below method.

Read from file and convert to JSON

import json
from pprint import pprint

# Considering "json_list.json" is a json file

with open('json_list.json') as fd:
     json_data = json.load(fd)
     pprint(json_data)

with statement automatically close the opened file descriptor.

String to JSON

import json
from pprint import pprint

json_data = json.loads('{"name" : "myName", "age":24}')
pprint(json_data)

SQL Last 6 Months

.... where yourdate_column > DATE_SUB(now(), INTERVAL 6 MONTH)

check if variable is dataframe

Use the built-in isinstance() function.

import pandas as pd

def f(var):
    if isinstance(var, pd.DataFrame):
        print("do stuff")

Why use the 'ref' keyword when passing an object?

With ref you can write:

static public void DoSomething(ref TestRef t)
{
    t = new TestRef();
}

And t will be changed after the method has completed.

change array size

No, try using a strongly typed List instead.

For example:

Instead of using

int[] myArray = new int[2];
myArray[0] = 1;
myArray[1] = 2;

You could do this:

List<int> myList = new List<int>();
myList.Add(1);
myList.Add(2);

Lists use arrays to store the data so you get the speed benefit of arrays with the convenience of a LinkedList by being able to add and remove items without worrying about having to manually change its size.

This doesn't mean an array's size (in this instance, a List) isn't changed though - hence the emphasis on the word manually.

As soon as your array hits its predefined size, the JIT will allocate a new array on the heap that is twice the size and copy your existing array across.

GridView sorting: SortDirection always Ascending

protected void gv_Sorting(object sender, GridViewSortEventArgs e)
{
    DataTable dataTable = (DataTable)Cache["GridData"];

    if (dataTable != null)
    {
        DataView dataView = new DataView(dataTable);
        string Field1 = e.SortExpression;
        string whichWay = "ASC";
        if (HttpContext.Current.Session[Field1] != null)
        {
            whichWay = HttpContext.Current.Session[Field1].ToString();
            if (whichWay == "ASC")
                whichWay = "DESC";
            else
                whichWay = "ASC";               
        }

        HttpContext.Current.Session[Field1] = whichWay;
        dataView.Sort = Field1 + " " + whichWay;      
        gv.DataSource = dataView;
        gv.DataBind();
    }
}

and you store the information that previously was retrieved

    string SqlConn = ConfigurationManager.ConnectionStrings["Sql28"].ConnectionString;
    SqlConnection sqlcon = new SqlConnection(SqlConn);
    sqlcon.Open();

    SqlCommand cmd = new SqlCommand();
    cmd.Connection = sqlcon;
    cmd.CommandType = System.Data.CommandType.Text;
    cmd.CommandText = HttpContext.Current.Session["sql"].ToString();

    SqlDataAdapter adapter = new SqlDataAdapter(cmd);
    DataTable employees = new DataTable();
    adapter.Fill(employees);

    gv.DataSource = employees;
    gv.DataBind();

    Cache.Insert("GridData", employees, null, System.Web.Caching.Cache.NoAbsoluteExpiration,new TimeSpan(0, 360000, 0));

jQuery table sort

I love this accepted answer, however, rarely do you get requirements to sort html and not have to add icons indicating the sorting direction. I took the accept answer's usage example and fixed that quickly by simply adding bootstrap to my project, and adding the following code:

<div></div>

inside each <th> so that you have a place to set the icon.

setIcon(this, inverse);

from the accepted answer's Usage, below the line:

th.click(function () {

and by adding the setIcon method:

function setIcon(element, inverse) {

        var iconSpan = $(element).find('div');

        if (inverse == false) {
            $(iconSpan).removeClass();
            $(iconSpan).addClass('icon-white icon-arrow-up');
        } else {
            $(iconSpan).removeClass();
            $(iconSpan).addClass('icon-white icon-arrow-down');
        }
        $(element).siblings().find('div').removeClass();
    }

Here is a demo. --You need to either run the demo in Firefox or IE, or disable Chrome's MIME-type checking for the demo to work. It depends on the sortElements Plugin, linked by the accepted answer, as an external resource. Just a heads up!

How to split one string into multiple variables in bash shell?

If you know it's going to be just two fields, you can skip the extra subprocesses like this:

var1=${STR%-*}
var2=${STR#*-}

What does this do? ${STR%-*} deletes the shortest substring of $STR that matches the pattern -* starting from the end of the string. ${STR#*-} does the same, but with the *- pattern and starting from the beginning of the string. They each have counterparts %% and ## which find the longest anchored pattern match. If anyone has a helpful mnemonic to remember which does which, let me know! I always have to try both to remember.

When should I use a trailing slash in my URL?

I'm always surprised by the extensive use of trailing slashes on non-directory URLs (WordPress among others). This really shouldn't be an either-or debate because putting a slash after a resource is semantically wrong. The web was designed to deliver addressable resources, and those addresses - URLs - were designed to emulate a *nix-style file-system hierarchy. In that context:

Slashes always denote directories, never files.
Files may be named anything (with or without extensions), but cannot contain or end with slashes.

Using these guidelines, it's wrong to put a slash after a non-directory resource.

What is a NullPointerException, and how do I fix it?

NullPointerExceptions are exceptions that occur when you try to use a reference that points to no location in memory (null) as though it were referencing an object. Calling a method on a null reference or trying to access a field of a null reference will trigger a NullPointerException. These are the most common, but other ways are listed on the NullPointerException javadoc page.

Probably the quickest example code I could come up with to illustrate a NullPointerException would be:

public class Example {

    public static void main(String[] args) {
        Object obj = null;
        obj.hashCode();
    }

}

On the first line inside main, I'm explicitly setting the Object reference obj equal to null. This means I have a reference, but it isn't pointing to any object. After that, I try to treat the reference as though it points to an object by calling a method on it. This results in a NullPointerException because there is no code to execute in the location that the reference is pointing.

(This is a technicality, but I think it bears mentioning: A reference that points to null isn't the same as a C pointer that points to an invalid memory location. A null pointer is literally not pointing anywhere, which is subtly different than pointing to a location that happens to be invalid.)

What is the "realm" in basic authentication

A realm can be seen as an area (not a particular page, it could be a group of pages) for which the credentials are used; this is also the string that will be shown when the browser pops up the login window, e.g.

Please enter your username and password for <realm name>:

When the realm changes, the browser may show another popup window if it doesn't have credentials for that particular realm.

Returning Arrays in Java

You need to do something with the return value...

import java.util.Arrays;

public class trial1{

    public static void main(String[] args){
        int[] B = numbers();
        System.out.println(Arrays.toString(B));
    }

    public static int[] numbers(){
        int[] A = {1,2,3};
        return A;
    }
}

Is there any method to get the URL without query string?

Try:

document.location.protocol + '//' +
document.location.host +
document.location.pathname;

(NB: .host rather than .hostname so that the port gets included too, if necessary)

How to check in Javascript if one element is contained within another

You should use Node.contains, since it's now standard and available in all browsers.

https://developer.mozilla.org/en-US/docs/Web/API/Node.contains

Make var_dump look pretty

I have make an addition to @AbraCadaver answers. I have included a javascript script which will delete php starting and closing tag. We will have clean more pretty dump.

May be somebody like this too.

function dd($data){
  highlight_string("<?php\n " . var_export($data, true) . "?>");
  echo '<script>document.getElementsByTagName("code")[0].getElementsByTagName("span")[1].remove() ;document.getElementsByTagName("code")[0].getElementsByTagName("span")[document.getElementsByTagName("code")[0].getElementsByTagName("span").length - 1].remove() ; </script>';
  die();
}

Result before:

Result After:

Now we don't have php starting and closing tag

What are the pros and cons of parquet format compared to other formats?

I think the main difference I can describe relates to record oriented vs. column oriented formats. Record oriented formats are what we're all used to -- text files, delimited formats like CSV, TSV. AVRO is slightly cooler than those because it can change schema over time, e.g. adding or removing columns from a record. Other tricks of various formats (especially including compression) involve whether a format can be split -- that is, can you read a block of records from anywhere in the dataset and still know it's schema? But here's more detail on columnar formats like Parquet.

Parquet, and other columnar formats handle a common Hadoop situation very efficiently. It is common to have tables (datasets) having many more columns than you would expect in a well-designed relational database -- a hundred or two hundred columns is not unusual. This is so because we often use Hadoop as a place to denormalize data from relational formats -- yes, you get lots of repeated values and many tables all flattened into a single one. But it becomes much easier to query since all the joins are worked out. There are other advantages such as retaining state-in-time data. So anyway it's common to have a boatload of columns in a table.

Let's say there are 132 columns, and some of them are really long text fields, each different column one following the other and use up maybe 10K per record.

While querying these tables is easy with SQL standpoint, it's common that you'll want to get some range of records based on only a few of those hundred-plus columns. For example, you might want all of the records in February and March for customers with sales > $500.

To do this in a row format the query would need to scan every record of the dataset. Read the first row, parse the record into fields (columns) and get the date and sales columns, include it in your result if it satisfies the condition. Repeat. If you have 10 years (120 months) of history, you're reading every single record just to find 2 of those months. Of course this is a great opportunity to use a partition on year and month, but even so, you're reading and parsing 10K of each record/row for those two months just to find whether the customer's sales are > $500.

In a columnar format, each column (field) of a record is stored with others of its kind, spread all over many different blocks on the disk -- columns for year together, columns for month together, columns for customer employee handbook (or other long text), and all the others that make those records so huge all in their own separate place on the disk, and of course columns for sales together. Well heck, date and months are numbers, and so are sales -- they are just a few bytes. Wouldn't it be great if we only had to read a few bytes for each record to determine which records matched our query? Columnar storage to the rescue!

Even without partitions, scanning the small fields needed to satisfy our query is super-fast -- they are all in order by record, and all the same size, so the disk seeks over much less data checking for included records. No need to read through that employee handbook and other long text fields -- just ignore them. So, by grouping columns with each other, instead of rows, you can almost always scan less data. Win!

But wait, it gets better. If your query only needed to know those values and a few more (let's say 10 of the 132 columns) and didn't care about that employee handbook column, once it had picked the right records to return, it would now only have to go back to the 10 columns it needed to render the results, ignoring the other 122 of the 132 in our dataset. Again, we skip a lot of reading.

(Note: for this reason, columnar formats are a lousy choice when doing straight transformations, for example, if you're joining all of two tables into one big(ger) result set that you're saving as a new table, the sources are going to get scanned completely anyway, so there's not a lot of benefit in read performance, and because columnar formats need to remember more about the where stuff is, they use more memory than a similar row format).

One more benefit of columnar: data is spread around. To get a single record, you can have 132 workers each read (and write) data from/to 132 different places on 132 blocks of data. Yay for parallelization!

And now for the clincher: compression algorithms work much better when it can find repeating patterns. You could compress AABBBBBBCCCCCCCCCCCCCCCC as 2A6B16C but ABCABCBCBCBCCCCCCCCCCCCCC wouldn't get as small (well, actually, in this case it would, but trust me :-) ). So once again, less reading. And writing too.

So we read a lot less data to answer common queries, it's potentially faster to read and write in parallel, and compression tends to work much better.

Columnar is great when your input side is large, and your output is a filtered subset: from big to little is great. Not as beneficial when the input and outputs are about the same.

But in our case, Impala took our old Hive queries that ran in 5, 10, 20 or 30 minutes, and finished most in a few seconds or a minute.

Hope this helps answer at least part of your question!

AVD Manager - Cannot Create Android Virtual Device

I had the same problem, although all required packages were installed. I closed down Eclipse, ran monitor.bat in the \android-sdks\tools\ folder, opened the AVD Manager from there, and I was able the create virtual devices here.

How do I delete an entity from symfony2

DELETE FROM ... WHERE id=...;

protected function templateRemove($id){
            $em = $this->getDoctrine()->getManager();
            $entity = $em->getRepository('XXXBundle:Templates')->findOneBy(array('id' => $id));

            if ($entity != null){
                $em->remove($entity);
                $em->flush();
            }
        }

JavaScript variable number of arguments to function

I agree with Ken's answer as being the most dynamic and I like to take it a step further. If it's a function that you call multiple times with different arguments - I use Ken's design but then add default values:

function load(context) {

    var defaults = {
        parameter1: defaultValue1,
        parameter2: defaultValue2,
        ...
    };

    var context = extend(defaults, context);

    // do stuff
}

This way, if you have many parameters but don't necessarily need to set them with each call to the function, you can simply specify the non-defaults. For the extend method, you can use jQuery's extend method ($.extend()), craft your own or use the following:

function extend() {
    for (var i = 1; i < arguments.length; i++)
        for (var key in arguments[i])
            if (arguments[i].hasOwnProperty(key))
                arguments[0][key] = arguments[i][key];
    return arguments[0];
}

This will merge the context object with the defaults and fill in any undefined values in your object with the defaults.

Java SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'") gives timezone as IST

You haven't set the timezone only added a Z to the end of the date/time, so it will look like a GMT date/time but this doesn't change the value.

Set the timezone to GMT and it will be correct.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));

How do I print bytes as hexadecimal?

This is a modified version of the Nibble to Hex method

void hexArrayToStr(unsigned char* info, unsigned int infoLength, char **buffer) {
    const char* pszNibbleToHex = {"0123456789ABCDEF"};
    int nNibble, i;
    if (infoLength > 0) {
        if (info != NULL) {
            *buffer = (char *) malloc((infoLength * 2) + 1);
            buffer[0][(infoLength * 2)] = 0;
            for (i = 0; i < infoLength; i++) {
                nNibble = info[i] >> 4;
                buffer[0][2 * i] = pszNibbleToHex[nNibble];
                nNibble = info[i] & 0x0F;
                buffer[0][2 * i + 1] = pszNibbleToHex[nNibble];
            }
        } else {
            *buffer = NULL;
        }
    } else {
        *buffer = NULL;
    }
}

Create SQLite database in android

Why not refer to the documentation or the sample code shipping with the SDK? There's code in the samples on how to create/update/fill/read databases using the helper class described in the document I linked.

Oracle - How to create a materialized view with FAST REFRESH and JOINS

The key checks for FAST REFRESH includes the following:

1) An Oracle materialized view log must be present for each base table.
2) The RowIDs of all the base tables must appear in the SELECT list of the MVIEW query definition.
3) If there are outer joins, unique constraints must be placed on the join columns of the inner table.

No 3 is easy to miss and worth highlighting here

ClassNotFoundException: org.slf4j.LoggerFactory

You'll need to download SLF4J's jars from the official site as either a zip (v1.7.4) or tar.gz (v1.7.4)

The download contains multiple jars based on how you want to use SLF4J. If you're simply trying to resolve the requirement of some other library (GWT, I assume) and don't really care about using SLF4J correctly, then I would probably pick the slf4j-api-1.7.4.jar since the Simple jar suggested by another answer does not contain, to my knowledge, the specific class you're looking for.

What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean?

I had this error once when I was trying to set my Outlets values from the prepare for segue method as follows:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let destination = segue.destination as? DestinationVC{

        if let item = sender as? DataItem{
            // This line pops up the error
            destination.nameLabel.text = item.name
        }
    }
}

Then I found out that I can't set the values of the destination controller outlets because the controller hasn't been loaded or initialized yet.

So I solved it this way:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let destination = segue.destination as? DestinationVC{

        if let item = sender as? DataItem{
            // Created this method in the destination Controller to update its outlets after it's being initialized and loaded
            destination.updateView(itemData:  item)
        }
    }
}

Destination Controller:

// This variable to hold the data received to update the Label text after the VIEW DID LOAD
var name = ""

// Outlets
@IBOutlet weak var nameLabel: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
    nameLabel.text = name
}

func updateView(itemDate: ObjectModel) {
    name = itemDate.name
}

I hope this answer helps anyone out there with the same issue as I found the marked answer is great resource to the understanding of optionals and how they work but hasn't addressed the issue itself directly.

Javascript - How to show escape characters in a string?

JavaScript uses the \ (backslash) as an escape characters for:

\' single quote
\" double quote
\ backslash
\n new line
\r carriage return
\t tab
\b backspace
\f form feed
\v vertical tab (IE < 9 treats '\v' as 'v' instead of a vertical tab ('\x0B'). If cross-browser compatibility is a concern, use \x0B instead of \v.)
\0 null character (U+0000 NULL) (only if the next character is not a decimal digit; else it’s an octal escape sequence)

Note that the \v and \0 escapes are not allowed in JSON strings.

How to import RecyclerView for Android L-preview

If anyone still has this issue - you don't have to change compileSdkVersion, this just defeats the whole purpose of support libraries.

Instead, use these in your gradle.build file:

compile 'com.android.support:cardview-v7:+'
compile 'com.android.support:recyclerview-v7:+'
compile 'com.android.support:palette-v7:+'`

Using reflection in Java to create a new instance with the reference variable type set to the new instance class name?

As an addendum to akf's answer you could use instanceof checks instead of String equals() calls:

String cname="com.some.vendor.Impl";
try {
  Class c=this.getClass().getClassLoader().loadClass(cname);
  Object o= c.newInstance();
  if(o instanceof Spam) {
    Spam spam=(Spam) o;
    process(spam);
  }
  else if(o instanceof Ham) {
    Ham ham = (Ham) o;
    process(ham);
  }
  /* etcetera */
}
catch(SecurityException se) {
  System.err.printf("Someone trying to game the system?%nOr a rename is in order because this JVM doesn't feel comfortable with: “%s”", cname);
  se.printStackTrace();
}
catch(LinkageError le) {
  System.err.printf("Seems like a bad class to this JVM: “%s”.", cname);
  le.printStackTrace();
}
catch(RuntimeException re) { 
  // runtime exceptions I might have forgotten. Classloaders are wont to produce those.
  re.printStackTrace();
}
catch(Exception e) { 
  e.printStackTrace();
}

Note the liberal hardcoding of some values. Anyways the main points are:

Use instanceof rather than equals(). If anything, it will co-operate better when refactoring.
Be sure to catch these runtime errors and security ones too.

How to find specific lines in a table using Selenium?

if you want to access table cell

WebElement thirdCell = driver.findElement(By.Xpath("//table/tbody/tr[2]/td[1]"));

If you want to access nested table cell -

WebElement thirdCell = driver.findElement(By.Xpath("//table/tbody/tr[2]/td[2]"+//table/tbody/tr[1]/td[2]));

For more details visit this Tutorial

Invoking modal window in AngularJS Bootstrap UI using JavaScript

Open modal windows with passing data to dialog

In case if someone interests to pass data to dialog:

app.controller('ModalCtrl', function($scope,  $modal) {
      
      $scope.name = 'theNameHasBeenPassed';

      $scope.showModal = function() {
        
        $scope.opts = {
        backdrop: true,
        backdropClick: true,
        dialogFade: false,
        keyboard: true,
        templateUrl : 'modalContent.html',
        controller : ModalInstanceCtrl,
        resolve: {} // empty storage
          };
          
        
        $scope.opts.resolve.item = function() {
            return angular.copy(
                                {name: $scope.name}
                          ); // pass name to resolve storage
        }
        
          var modalInstance = $modal.open($scope.opts);
          
          modalInstance.result.then(function(){
            //on ok button press 
          },function(){
            //on cancel button press
            console.log("Modal Closed");
          });
      };                   
})

var ModalInstanceCtrl = function($scope, $modalInstance, $modal, item) {
    
     $scope.item = item;
    
      $scope.ok = function () {
        $modalInstance.close();
      };
      
      $scope.cancel = function () {
        $modalInstance.dismiss('cancel');
      };
}

Demo Plunker

generating variable names on fly in python

Though I don't see much point, here it is:

for i in xrange(0, len(prices)):
    exec("price%d = %s" % (i + 1, repr(prices[i])));

Optimal way to DELETE specified rows from Oracle

Store all the to be deleted ID's into a table. Then there are 3 ways. 1) loop through all the ID's in the table, then delete one row at a time for X commit interval. X can be a 100 or 1000. It works on OLTP environment and you can control the locks.

2) Use Oracle Bulk Delete

3) Use correlated delete query.

Single query is usually faster than multiple queries because of less context switching, and possibly less parsing.

How to format DateTime columns in DataGridView?

I used these code Hope it could help

dataGridView2.Rows[n].Cells[3].Value = item[2].ToString();
dataGridView2.Rows[n].Cells[3].Value = Convert.ToDateTime(item[2].ToString()).ToString("d");

The required anti-forgery form field "__RequestVerificationToken" is not present Error in user Registration

All the other answers in here are also valid, but if none of them solve the issue it is also worth checking that the actual headers are being passed to the server.

For example, in a load balanced environment behind nginx, the default configuration is to strip out the __RequestVerificationToken header before passing the request on to the server, see: simple nginx reverse proxy seems to strip some headers

How do I check if string contains substring?

I know that best way is str.indexOf(s) !== -1; http://hayageek.com/javascript-string-contains/

I suggest another way(str.replace(s1, "") !== str):

_x000D_

var str = "Hello World!", s1 = "ello", s2 = "elloo";_x000D_
alert(str.replace(s1, "") !== str);_x000D_
alert(str.replace(s2, "") !== str);

_x000D_

Shortcut to create properties in Visual Studio?

Type P + Tab + Tab.

Change the datatype, press TAB, change the property name, and press End + Enter.

What is the difference between declarative and imperative paradigm in programming?

Stealing from Philip Roberts here:

Imperative programming tells the machine how to do something (resulting in what you want to happen)
Declarative programming tells the machine what you would like to happen (and the computer figures out how to do it)

Two examples:

1. Doubling all numbers in an array

Imperatively:

var numbers = [1,2,3,4,5]
var doubled = []

for(var i = 0; i < numbers.length; i++) {
  var newNumber = numbers[i] * 2
  doubled.push(newNumber)
}
console.log(doubled) //=> [2,4,6,8,10]

Declaratively:

var numbers = [1,2,3,4,5]

var doubled = numbers.map(function(n) {
  return n * 2
})
console.log(doubled) //=> [2,4,6,8,10]

2. Summing all items in a list

Imperatively

var numbers = [1,2,3,4,5]
var total = 0

for(var i = 0; i < numbers.length; i++) {
  total += numbers[i]
}
console.log(total) //=> 15

Declaratively

var numbers = [1,2,3,4,5]

var total = numbers.reduce(function(sum, n) {
  return sum + n
});
console.log(total) //=> 15

Note how the imperative examples involve creating a new variable, mutating it, and returning that new value (i.e., how to make something happen), whereas the declarative examples execute on a given input and return the new value based on the initial input (i.e., what we want to happen).

How to throw an exception in C?

As mentioned in numerous threads, the "standard" way of doing this is using setjmp/longjmp. I posted yet another such solution to https://github.com/psevon/exceptions-and-raii-in-c This is to my knowledge the only solution that relies on automatic cleanup of allocated resources. It implements unique and shared smartpointers, and allows intermediate functions to let exceptions pass through without catching and still have their locally allocated resources cleaned up properly.

Why do I need to explicitly push a new branch?

At first check

Step-1: git remote -v
//if found git initialize then remove or skip step-2

Step-2: git remote rm origin
//Then configure your email address globally git

Step-3: git config --global user.email "[email protected]"

Step-4: git initial

Step-5: git commit -m "Initial Project"
//If already add project repo then skip step-6

Step-6: git remote add origin %repo link from bitbucket.org%

Step-7: git push -u origin master

Write in body request with HttpClient

Extending your code (assuming that the XML you want to send is in xmlString) :

String xmlString = "</xml>";
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpRequest = new HttpPost(this.url);
httpRequest.setHeader("Content-Type", "application/xml");
StringEntity xmlEntity = new StringEntity(xmlString);
httpRequest.setEntity(xmlEntity );
HttpResponse httpresponse = httpclient.execute(httppost);

How to add a filter class in Spring Boot?

Filters as the name suggest used to perform filtering on either the request to a resource or on the response from a resource, or both. Spring Boot provides few options to register custom filters in the Spring Boot application. Let’s look at the different options.

1. Define Spring Boot Filter and Invocation Order

Implement Filter interface to create a new filter in Spring Boot.

@Configuration
@Order(Ordered.HIGHEST_PRECEDENCE)
public class CustomFilter implements Filter {

 private static final Logger LOGGER = LoggerFactory.getLogger(CustomFilter.class);

 @Override
 public void init(FilterConfig filterConfig) throws ServletException {
  LOGGER.info("########## Initiating Custom filter ##########");
 }

 @Override
 public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

  HttpServletRequest request = (HttpServletRequest) servletRequest;
  HttpServletResponse response = (HttpServletResponse) servletResponse;

  LOGGER.info("Logging Request  {} : {}", request.getMethod(), request.getRequestURI());

  //call next filter in the filter chain
  filterChain.doFilter(request, response);

  LOGGER.info("Logging Response :{}", response.getContentType());
 }

 @Override
 public void destroy() {
  // TODO: 7/4/18
 }
}

Let’s quickly look at some important points in the above code

The filter registered by @Component annotation.

To fire filters in the right order–we needed to use the @Order annotation.

@Component
@Order(1)
public class CustomFirstFilter implements Filter {

}
@Component
@Order(2)
public class CustomSecondFilter implements Filter {

}

In the above code, CustomFirstFilter will run before the CustomSecondFilter.

The lower the number, the higher the precedence

2. URL Pattern

If the convention-based mapping is not flexible enough, we can use FilterRegistrationBean for the complete control of the application. Here, don’t use @Component annotation for the filter class but register the filter using a FilterRegistrationBean.

 public class CustomURLFilter implements Filter {

 private static final Logger LOGGER = LoggerFactory.getLogger(CustomURLFilter.class);

 @Override
 public void init(FilterConfig filterConfig) throws ServletException {
  LOGGER.info("########## Initiating CustomURLFilter filter ##########");
 }

 @Override
 public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

  HttpServletRequest request = (HttpServletRequest) servletRequest;
  HttpServletResponse response = (HttpServletResponse) servletResponse;

  LOGGER.info("This Filter is only called when request is mapped for /customer resource");

  //call next filter in the filter chain
  filterChain.doFilter(request, response);
 }

 @Override
 public void destroy() {

 }
}

@Configuration
public class AppConfig {

 @Bean
 public FilterRegistrationBean < CustomURLFilter > filterRegistrationBean() {
  FilterRegistrationBean < CustomURLFilter > registrationBean = new FilterRegistrationBean();
  CustomURLFilter customURLFilter = new CustomURLFilter();

  registrationBean.setFilter(customURLFilter);
  registrationBean.addUrlPatterns("/greeting/*");
  registrationBean.setOrder(2); //set precedence
  return registrationBean;
 }
}

Need a query that returns every field that contains a specified letter

try this

Select * From Table
Where field like '%' + ltrValue1 + '%'
  And field like '%' + ltrValue2 + '%'
... etc.

and be prepared for a table scan as this functionality cannot use any existing indices

How to shift a column in Pandas DataFrame

This is how I do it:

df_ext = pd.DataFrame(index=pd.date_range(df.index[-1], periods=8, closed='right'))
df2 = pd.concat([df, df_ext], axis=0, sort=True)
df2["forecast"] = df2["some column"].shift(7)

Basically I am generating an empty dataframe with the desired index and then just concatenate them together. But I would really like to see this as a standard feature in pandas so I have proposed an enhancement to pandas.

Is an HTTPS query string secure?

Yes, it is. But using GET for sensitive data is a bad idea for several reasons:

Mostly HTTP referrer leakage (an external image in the target page might leak the password[1])
Password will be stored in server logs (which is obviously bad)
History caches in browsers

Therefore, even though Querystring is secured it's not recommended to transfer sensitive data over querystring.

[1] Although I need to note that RFC states that browser should not send referrers from HTTPS to HTTP. But that doesn't mean a bad 3rd party browser toolbar or an external image/flash from an HTTPS site won't leak it.

Cast object to T

try

if (readData is T)
    return (T)(object)readData;

Javascript: Extend a Function

Another option could be:

var initial = function() {
    console.log( 'initial function!' );
}

var iWantToExecuteThisOneToo = function () {
    console.log( 'the other function that i wanted to execute!' );
}

function extendFunction( oldOne, newOne ) {
    return (function() {
        oldOne();
        newOne();
    })();
}

var extendedFunction = extendFunction( initial, iWantToExecuteThisOneToo );

Javascript: How to loop through ALL DOM elements on a page?

Andy E. gave a good answer.

I would add, if you feel to select all the childs in some special selector (this need happened to me recently), you can apply the method "getElementsByTagName()" on any DOM object you want.

For an example, I needed to just parse "visual" part of the web page, so I just made this

var visualDomElts = document.body.getElementsByTagName('*');

This will never take in consideration the head part.

How do I to insert data into an SQL table using C# as well as implement an upload function?

You should use parameters in your query to prevent attacks, like if someone entered '); drop table ArticlesTBL;--' as one of the values.

string query = "INSERT INTO ArticlesTBL (ArticleTitle, ArticleContent, ArticleType, ArticleImg, ArticleBrief,  ArticleDateTime, ArticleAuthor, ArticlePublished, ArticleHomeDisplay, ArticleViews)";
query += " VALUES (@ArticleTitle, @ArticleContent, @ArticleType, @ArticleImg, @ArticleBrief, @ArticleDateTime, @ArticleAuthor, @ArticlePublished, @ArticleHomeDisplay, @ArticleViews)";

SqlCommand myCommand = new SqlCommand(query, myConnection);
myCommand.Parameters.AddWithValue("@ArticleTitle", ArticleTitleTextBox.Text);
myCommand.Parameters.AddWithValue("@ArticleContent", ArticleContentTextBox.Text);
// ... other parameters
myCommand.ExecuteNonQuery();

Exploits of a Mom

(xkcd)

How to check if an element exists in the xml using xpath?

Use:

boolean(/*/*[@subjectIdentifier="Primary"]/*/*/*/*
                           [name()='AttachedXml' 
                          and 
                            namespace-uri()='http://xml.mycompany.com/XMLSchema'
                           ]
       )

Convert JavaScript string in dot notation into an object reference

You can use the library available at npm, which simplifies this process. https://www.npmjs.com/package/dot-object

 var dot = require('dot-object');

var obj = {
 some: {
   nested: {
     value: 'Hi there!'
   }
 }
};

var val = dot.pick('some.nested.value', obj);
console.log(val);

// Result: Hi there!

jQuery posting JSON

You post JSON like this

$.ajax(url, {
    data : JSON.stringify(myJSObject),
    contentType : 'application/json',
    type : 'POST',
    ...

if you pass an object as settings.data jQuery will convert it to query parameters and by default send with the data type application/x-www-form-urlencoded; charset=UTF-8, probably not what you want

Apache won't follow symlinks (403 Forbidden)

Yet another subtle pitfall, in case you need AllowOverride All:

Somewhere deep in the fs tree, an old .htaccess having

Options Indexes

instead of

Options +Indexes

was all it took to nonchalantly disable the FollowSymLinks set in the server config, and cause a mysterious 403 here.

Best way to access web camera in Java

I think the project you are looking for is: https://github.com/sarxos/webcam-capture (I'm the author)

There is an example working exactly as you've described - after it's run, the window appear where, after you press "Start" button, you can see live image from webcam device and save it to file after you click on "Snapshot" (source code available, please note that FPS counter in the corner can be disabled):

snapshot

The project is portable (WinXP, Win7, Win8, Linux, Mac, Raspberry Pi) and does not require any additional software to be installed on the PC.

API is really nice and easy to learn. Example how to capture single image and save it to PNG file:

Webcam webcam = Webcam.getDefault();
webcam.open();
ImageIO.write(webcam.getImage(), "PNG", new File("test.png"));

Creating a jQuery object from a big HTML-string

There is also a great library called cheerio designed specifically for this.

Fast, flexible, and lean implementation of core jQuery designed specifically for the server.

var cheerio = require('cheerio'),
    $ = cheerio.load('<h2 class="title">Hello world</h2>');

$('h2.title').text('Hello there!');
$('h2').addClass('welcome');

$.html();
//=> <h2 class="title welcome">Hello there!</h2>

best way to get folder and file list in Javascript

In my project I use this function for getting huge amount of files. It's pretty fast (put require("FS") out to make it even faster):

var _getAllFilesFromFolder = function(dir) {

    var filesystem = require("fs");
    var results = [];

    filesystem.readdirSync(dir).forEach(function(file) {

        file = dir+'/'+file;
        var stat = filesystem.statSync(file);

        if (stat && stat.isDirectory()) {
            results = results.concat(_getAllFilesFromFolder(file))
        } else results.push(file);

    });

    return results;

};

usage is clear:

_getAllFilesFromFolder(__dirname + "folder");

What is the difference between HTTP status code 200 (cache) vs status code 304?

200 (cache) means Firefox is simply using the locally cached version. This is the fastest because no request to the Web server is made.

304 means Firefox is sending a "If-Modified-Since" conditional request to the Web server. If the file has not been updated since the date sent by the browser, the Web server returns a 304 response which essentially tells Firefox to use its cached version. It is not as fast as 200 (cache) because the request is still sent to the Web server, but the server doesn't have to send the contents of the file.

To your last question, I don't know why the two JavaScript files in the same directory are returning different results.

Synchronizing a local Git repository with a remote one

(This info is from The Git User's Manual)

I'm also learning, so this might not be exactly an answer to the question but it might help somebody:

When a remote repository is initially cloned copies of all branches are stored in your local repository (view them with git branch -r)
To update these copies and make them current (i.e. sync them with the remote branch) use git fetch. This will not effect any of you existing, custom created branches.
To override your local branch checkout a fresh version of whatever branch you are working on (Assuming that you have already executed git add origin /path/to/repository) use git checkout origin/branch_name, this will override your locals changes on branch branch_name

Proper usage of Java -D command-line parameters

You're giving parameters to your program instead to Java. Use

java -Dtest="true" -jar myApplication.jar

instead.

Consider using

"true".equalsIgnoreCase(System.getProperty("test"))

to avoid the NPE. But do not use "Yoda conditions" always without thinking, sometimes throwing the NPE is the right behavior and sometimes something like

System.getProperty("test") == null || System.getProperty("test").equalsIgnoreCase("true")

is right (providing default true). A shorter possibility is

!"false".equalsIgnoreCase(System.getProperty("test"))

but not using double negation doesn't make it less hard to misunderstand.

How do I compare two DateTime objects in PHP 5.2.8?

If you want to compare dates and not time, you could use this:

$d1->format("Y-m-d") == $d2->format("Y-m-d")

FCM getting MismatchSenderId

I had the same error while trying to send push notificaion. Get the updated google-services.json file and replaced with it. Worked for me.

PL/SQL ORA-01422: exact fetch returns more than requested number of rows

A SELECT INTO statement will throw an error if it returns anything other than 1 row. If it returns 0 rows, you'll get a no_data_found exception. If it returns more than 1 row, you'll get a too_many_rows exception. Unless you know that there will always be exactly 1 employee with a salary greater than 3000, you do not want a SELECT INTO statement here.

Most likely, you want to use a cursor to iterate over (potentially) multiple rows of data (I'm also assuming that you intended to do a proper join between the two tables rather than doing a Cartesian product so I'm assuming that there is a departmentID column in both tables)

BEGIN
  FOR rec IN (SELECT EMPLOYEE.EMPID, 
                     EMPLOYEE.ENAME, 
                     EMPLOYEE.DESIGNATION, 
                     EMPLOYEE.SALARY,  
                     DEPARTMENT.DEPT_NAME 
                FROM EMPLOYEE, 
                     DEPARTMENT 
               WHERE employee.departmentID = department.departmentID
                 AND EMPLOYEE.SALARY > 3000)
  LOOP
    DBMS_OUTPUT.PUT_LINE ('Employee Nnumber: ' || rec.EMPID);
    DBMS_OUTPUT.PUT_LINE ('---------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Name: ' || rec.ENAME);
    DBMS_OUTPUT.PUT_LINE ('---------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Designation: ' || rec.DESIGNATION);
    DBMS_OUTPUT.PUT_LINE ('----------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Salary: ' || rec.SALARY);
    DBMS_OUTPUT.PUT_LINE ('----------------------------------------------------');
    DBMS_OUTPUT.PUT_LINE ('Employee Department: ' || rec.DEPT_NAME);
  END LOOP;
END;

I'm assuming that you are just learning PL/SQL as well. In real code, you'd never use dbms_output like this and would not depend on anyone seeing data that you write to the dbms_output buffer.

How do you get the currently selected <option> in a <select> via JavaScript?

Using the selectedOptions property:

var yourSelect = document.getElementById("your-select-id");
alert(yourSelect.selectedOptions[0].value);

It works in all browsers except Internet Explorer.

What's the difference between passing by reference vs. passing by value?

Here is an example that demonstrates the differences between pass by value - pointer value - reference:

void swap_by_value(int a, int b){
    int temp;

    temp = a;
    a = b;
    b = temp;
}   
void swap_by_pointer(int *a, int *b){
    int temp;

    temp = *a;
    *a = *b;
    *b = temp;
}    
void swap_by_reference(int &a, int &b){
    int temp;

    temp = a;
    a = b;
    b = temp;
}

int main(void){
    int arg1 = 1, arg2 = 2;

    swap_by_value(arg1, arg2);
    cout << arg1 << " " << arg2 << endl;    //prints 1 2

    swap_by_pointer(&arg1, &arg2);
    cout << arg1 << " " << arg2 << endl;    //prints 2 1

    arg1 = 1;                               //reset values
    arg2 = 2;
    swap_by_reference(arg1, arg2);
    cout << arg1 << " " << arg2 << endl;    //prints 2 1
}

The “passing by reference” method has an important limitation. If a parameter is declared as passed by reference (so it is preceded by the & sign) its corresponding actual parameter must be a variable.

An actual parameter referring to “passed by value” formal parameter may be an expression in general, so it is allowed to use not only a variable but also a literal or even a function invocation's result.

The function is not able to place a value in something other than a variable. It cannot assign a new value to a literal or force an expression to change its result.

PS: You can also check Dylan Beattie answer in the current thread that explains it in plain words.

Razor MVC Populating Javascript array with Model Array

If it is a symmetrical (rectangular) array then Try pushing into a single dimension javascript array; use razor to determine the array structure; and then transform into a 2 dimensional array.

// this just sticks them all in a one dimension array of rows * cols
var myArray = new Array();
@foreach (var d in Model.ResultArray)
{
    @:myArray.push("@d");
}

var MyA = new Array();

var rows = @Model.ResultArray.GetLength(0);
var cols = @Model.ResultArray.GetLength(1);

// now convert the single dimension array to 2 dimensions
var NewRow;
var myArrayPointer = 0;

for (rr = 0; rr < rows; rr++)
{
  NewRow = new Array();
  for ( cc = 0; cc < cols; cc++)
  {
    NewRow.push(myArray[myArrayPointer]);
    myArrayPointer++;
  }
  MyA.push(NewRow);
}

How to update a single pod without touching other dependencies

pod update POD_NAME will update latest pod but not update Podfile.lock file.

So, you may update your Podfile with specific version of your pod e.g pod 'POD_NAME', '~> 2.9.0' and then use command pod install

Later, you can remove the specific version naming from your Podfile and can again use pod install. This will helps to keep Podfile.lock updated.

How do I disable "missing docstring" warnings at a file-level in Pylint?

No. Pylint doesn't currently let you discriminate between doc-string warnings.

However, you can use Flake8 for all Python code checking along with the doc-string extension to ignore this warning.

Install the doc-string extension with pip (internally, it uses pydocstyle).

pip install flake8_docstrings

You can then just use the --ignore D100 switch. For example, flake8 file.py --ignore D100

Should you use rgba(0, 0, 0, 0) or rgba(255, 255, 255, 0) for transparency in CSS?

The last parameter to the rgba() function is the "alpha" or "opacity" parameter. If you set it to 0 it will mean "completely transparent", and the first three parameters (the red, green, and blue channels) won't matter because you won't be able to see the color anyway.

With that in mind, I would choose rgba(0, 0, 0, 0) because:

it's less typing,
it keeps a few extra bytes out of your CSS file, and
you will see an obvious problem if the alpha value changes to something undesirable.

You could avoid the rgba model altogether and use the transparent keyword instead, which according to w3.org, is equivalent to "transparent black" and should compute to rgba(0, 0, 0, 0). For example:

h1 {
    background-color: transparent;
}

This saves you yet another couple bytes while your intentions of using transparency are obvious (in case one is unfamiliar with RGBA).

As of CSS3, you can use the transparent keyword for any CSS property that accepts a color.

1114 (HY000): The table is full

I fixed this problem by increasing the amount of memory available to the vagrant VM where the database was located.

Convert array to string in NodeJS

In node, you can just say

console.log(aa)

and it will format it as it should.

If you need to use the resulting string you should use

JSON.stringify(aa)

Display number always with 2 decimal places in <input>

Another shorthand to (@maudulus's answer) to remove {maxFractionDigits} since it's optional.

You can use {{numberExample | number : '1.2'}}

Use multiple custom fonts using @font-face?

Check out fontsquirrel. They have a web font generator, which will also spit out a suitable stylesheet for your font (look for "@font-face kit"). This stylesheet can be included in your own, or you can use it as a template.

How connect Postgres to localhost server using pgAdmin on Ubuntu?

You haven't created a user db. If its just a fresh install, the default user is postgres and the password should be blank. After you access it, you can create the users you need.

Is there a way for non-root processes to bind to "privileged" ports on Linux?

Since the OP is just development/testing, less than sleek solutions may be helpful:

setcap can be used on a script's interpreter to grant capabilities to scripts. If setcaps on the global interpreter binary is not acceptable, make a local copy of the binary (any user can) and get root to setcap on this copy. Python2 (at least) works properly with a local copy of the interpreter in your script development tree. No suid is needed so the root user can control to what capabilities users have access.

If you need to track system-wide updates to the interpreter, use a shell script like the following to run your script:

#!/bin/sh
#
#  Watch for updates to the Python2 interpreter

PRG=python_net_raw
PRG_ORIG=/usr/bin/python2.7

cmp $PRG_ORIG $PRG || {
    echo ""
    echo "***** $PRG_ORIG has been updated *****"
    echo "Run the following commands to refresh $PRG:"
    echo ""
    echo "    $ cp $PRG_ORIG $PRG"
    echo "    # setcap cap_net_raw+ep $PRG"
    echo ""
    exit
}

./$PRG $*

Chmod 777 to a folder and all contents

If by all permissions you mean 777

Navigate to folder and

chmod -R 777 .

Absolute vs relative URLs

In general, it is considered best-practice to use relative URLs, so that your website will not be bound to the base URL of where it is currently deployed. For example, it will be able to work on localhost, as well as on your public domain, without modifications.

Parse HTML table to Python list?

If the HTML is not XML you can't do it with etree. But even then, you don't have to use an external library for parsing a HTML table. In python 3 you can reach your goal with HTMLParser from html.parser. I've the code of the simple derived HTMLParser class here in a github repo.

You can use that class (here named HTMLTableParser) the following way:

import urllib.request
from html_table_parser import HTMLTableParser

target = 'http://www.twitter.com'

# get website content
req = urllib.request.Request(url=target)
f = urllib.request.urlopen(req)
xhtml = f.read().decode('utf-8')

# instantiate the parser and feed it
p = HTMLTableParser()
p.feed(xhtml)
print(p.tables)

The output of this is a list of 2D-lists representing tables. It looks maybe like this:

[[['   ', ' Anmelden ']],
 [['Land', 'Code', 'Für Kunden von'],
  ['Vereinigte Staaten', '40404', '(beliebig)'],
  ['Kanada', '21212', '(beliebig)'],
  ...
  ['3424486444', 'Vodafone'],
  ['  Zeige SMS-Kurzwahlen für andere Länder ']]]

IDEA: javac: source release 1.7 requires target release 1.7

I've hit this after just minor upgrade from IntelliJ IDEA 14 to v14.1. For me changing an edit of top/parent pom helped and then clicked re-import Maven (if it is not automatic).

But it maybe just enough to Right Click on module(s)/aggregated/parent module and Maven -> Reimport.

How to pass dictionary items as function arguments in python?

If you want to use them like that, define the function with the variable names as normal:

def my_function(school, standard, city, name):
    schoolName  = school
    cityName = city
    standardName = standard
    studentName = name

Now you can use ** when you call the function:

data = {'school':'DAV', 'standard': '7', 'name': 'abc', 'city': 'delhi'}

my_function(**data)

and it will work as you want.

P.S. Don't use reserved words such as class.(e.g., use klass instead)

How to place div side by side

There are many ways to do what you're asking for:

Using CSS float property:

_x000D_

 <div style="width: 100%; overflow: hidden;">
     <div style="width: 600px; float: left;"> Left </div>
     <div style="margin-left: 620px;"> Right </div>
</div>

_x000D_

Using CSS display property - which can be used to make divs act like a table:

_x000D_

<div style="width: 100%; display: table;">
    <div style="display: table-row">
        <div style="width: 600px; display: table-cell;"> Left </div>
        <div style="display: table-cell;"> Right </div>
    </div>
</div>

_x000D_

There are more methods, but those two are the most popular.

Is JavaScript object-oriented?

JavaScript is a prototype-based programming language (probably prototype-based scripting language is more correct definition). It employs cloning and not inheritance. A prototype-based programming language is a style of object-oriented programming without classes. While object-oriented programming languages encourages development focus on taxonomy and relationships, prototype-based programming languages encourages to focus on behavior first and then later classify.

The term “object-oriented” was coined by Alan Kay in 1967, who explains it in 2003 to mean

only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. ^(source)

In object-oriented programming, each object is capable of receiving messages, processing data, and sending messages to other objects.

For a language to be object-oriented in may include features as encapsulation, modularity, polymorphism, and inheritance, but it is not a requirement. Object-oriented programming languages that make use of classes are often referred to as classed-based programming languages, but it is by no means a must to make use of classes to be object-oriented.

JavaScript uses prototypes to define object properties, including methods and inheritance.

Conclusion: JavaScript IS object-oriented.

How to create a DataFrame from a text file in Spark

Update - as of Spark 1.6, you can simply use the built-in csv data source:

spark: SparkSession = // create the Spark Session
val df = spark.read.csv("file.txt")

You can also use various options to control the CSV parsing, e.g.:

val df = spark.read.option("header", "false").csv("file.txt")

For Spark version < 1.6: The easiest way is to use spark-csv - include it in your dependencies and follow the README, it allows setting a custom delimiter (;), can read CSV headers (if you have them), and it can infer the schema types (with the cost of an extra scan of the data).

Alternatively, if you know the schema you can create a case-class that represents it and map your RDD elements into instances of this class before transforming into a DataFrame, e.g.:

case class Record(id: Int, name: String)

val myFile1 = myFile.map(x=>x.split(";")).map {
  case Array(id, name) => Record(id.toInt, name)
} 

myFile1.toDF() // DataFrame will have columns "id" and "name"

load csv into 2D matrix with numpy for plotting

Pure numpy

numpy.loadtxt(open("test.csv", "rb"), delimiter=",", skiprows=1)

Check out the loadtxt documentation.

You can also use python's csv module:

import csv
import numpy
reader = csv.reader(open("test.csv", "rb"), delimiter=",")
x = list(reader)
result = numpy.array(x).astype("float")

You will have to convert it to your favorite numeric type. I guess you can write the whole thing in one line:

result = numpy.array(list(csv.reader(open("test.csv", "rb"), delimiter=","))).astype("float")

Added Hint:

You could also use pandas.io.parsers.read_csv and get the associated numpy array which can be faster.

Not able to access adb in OS X through Terminal, "command not found"

The problem is: adb is not in your PATH. This is where the shell looks for executables. You can check your current PATH with echo $PATH.

Bash will first try to look for a binary called adb in your Path, and not in the current directory. Therefore, if you are currently in the platform-tools directory, just call

./adb --help

The dot is your current directory, and this tells Bash to use adb from there.

But actually, you should add platform-tools to your PATH, as well as some other tools that the Android SDK comes with. This is how you do it:

Find out where you installed the Android SDK. This might be (where $HOME is your user's home directory) one of the following (or verify via Configure > SDK Manager in the Android Studio startup screen):
- Linux: $HOME/Android/Sdk
- macOS: $HOME/Library/Android/sdk
Find out which shell profile to edit, depending on which file is used:
- Linux: typically $HOME/.bashrc
- macOS: typically $HOME/.bash_profile
- With Zsh: $HOME/.zshrc
Open the shell profile from step two, and at the bottom of the file, add the following lines. Make sure to replace the path with the one where you installed platform-tools if it differs:
```
export ANDROID_HOME="$HOME/Android/Sdk"
export PATH="$ANDROID_HOME/tools:$ANDROID_HOME/tools/bin:$ANDROID_HOME/platform-tools:$PATH"
```
Save the profile file, then, re-start the terminal or run source ~/.bashrc (or whatever you just modified).

Note that setting ANDROID_HOME is required for some third party frameworks, so it does not hurt to add it.

Rename multiple columns by names

If one row of the data contains the names you want to change all columns to you can do

names(data) <- data[row,]

Given data is your dataframe and row is the row number containing the new values.

Then you can remove the row containing the names with

data <- data[-row,]

Datatables: Cannot read property 'mData' of undefined

I had a dynamically generated, but badly formed table with a typo. I copied a <td> tag inside another <td> by mistake. My column count matched. I had <thead> and <tbody> tags. Everything matched, except for this little mistake I didn't notice for a while, because my column had a lot of link and image tags in it.

Is there a way to get a list of all current temporary tables in SQL Server?

For SQL Server 2000, this should tell you only the #temp tables in your session. (Adapted from my example for more modern versions of SQL Server here.) This assumes you don't name your tables with three consecutive underscores, like CREATE TABLE #foo___bar:

SELECT 
  name = SUBSTRING(t.name, 1, CHARINDEX('___', t.name)-1),
  t.id
FROM tempdb..sysobjects AS t
WHERE t.name LIKE '#%[_][_][_]%'
AND t.id = 
  OBJECT_ID('tempdb..' + SUBSTRING(t.name, 1, CHARINDEX('___', t.name)-1));

How to set input type date's default value to today?

use moment.js to solve this issue in 2 lines, html5 date input type only accept "YYYY-MM-DD" this format. I solve my problem this way.

var today = moment().format('YYYY-MM-DD');
 $('#datePicker').val(today);

this is simplest way to solve this issue.

MVC web api: No 'Access-Control-Allow-Origin' header is present on the requested resource

Avoid multiple place enabling CORS,Like WebApiCOnfig.cs, GrantResourceOwnerCredentials method in provider and Controller Header attribute etc. Below are the list which also cause the Access Control Allow Origin

Web having truble in interacting with DB which you used.
AWS Cloud If VPC of Web API and DB are different.

Below code is more then enough to fix the access control allow origin. //Make sure app.UseCors should be top of the code line of configuration.

   public partial class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);
            //All other configurations
        }
    }

This slowed my problem.

javascript compare strings without being case sensitive

Try this...

if(string1.toLowerCase() == string2.toLowerCase()){
    return true;
}

Also, it's not a loop, it's a block of code. Loops are generally repeated (although they can possibly execute only once), whereas a block of code never repeats.

I read your note about not using toLowerCase, but can't see why it would be a problem.

How to create a file in Ruby

File.new and File.open default to read mode ('r') as a safety mechanism, to avoid possibly overwriting a file. We have to explicitly tell Ruby to use write mode ('w' is the most common way) if we're going to output to the file.

If the text to be output is a string, rather than write:

File.open('foo.txt', 'w') { |fo| fo.puts "bar" }

or worse:

fo = File.open('foo.txt', 'w')
fo.puts "bar"
fo.close

Use the more succinct write:

File.write('foo.txt', 'bar')

write has modes allowed so we can use 'w', 'a', 'r+' if necessary.

open with a block is useful if you have to compute the output in an iterative loop and want to leave the file open as you do so. write is useful if you are going to output the content in one blast then close the file.

See the documentation for more information.

Can a unit test project load the target application's app.config file?

If you application is using setting such as Asp.net ConnectionString you need to add the attribute HostType to your method, else they wont load even if you have an App.Config file.

[TestMethod]
[HostType("ASP.NET")] // will load the ConnectionString from the App.Config file
public void Test() {

}

Android Studio - How to increase Allocated Heap Size

Or, you can go to your android-studio\bin folder and change these -Xmx and -Xms values in studio.exe.vmoptions or studio64.exe.vmoptions files (depending on which version you are running).

Bundler::GemNotFound: Could not find rake-10.3.2 in any of the sources

Bundler 2

If you need to update from bundler v1 to v2 follow this official guide.

For a fast solution:

In root fo your application run bundle config set path "/bundle" to add a custom path for bundler use, in this case I set /bundle, you can use whatever.

1.2 [Alternative solution] You can use a bundler file (~/.bundle/config) also, to use this I recommend set bundler folders in environment, like a Docker image, for example. Here the official guide.
You don't need to delete your Gemfile.lock, It's a bad practice and this can cause other future problems. Commit Gemfile.lock normaly, sometimes you need to update your bundle with bundle install or install individual gem.

You can see all the configs for bundler version 2 here.

passing JSON data to a Spring MVC controller

Add the following dependencies

<dependency>
    <groupId>org.codehaus.jackson</groupId> 
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.9.7</version>
</dependency>

<dependency>
    <groupId>org.codehaus.jackson</groupId> 
    <artifactId>jackson-core-asl</artifactId>
    <version>1.9.7</version>
</dependency>

Modify request as follows

$.ajax({ 
    url:urlName,    
    type:"POST", 
    contentType: "application/json; charset=utf-8",
    data: jsonString, //Stringified Json Object
    async: false,    //Cross-domain requests and dataType: "jsonp" requests do not support synchronous operation
    cache: false,    //This will force requested pages not to be cached by the browser          
    processData:false, //To avoid making query String instead of JSON
    success: function(resposeJsonObject){
        // Success Message Handler
    }
});

Controller side

@RequestMapping(value = urlPattern , method = RequestMethod.POST)
public @ResponseBody Person save(@RequestBody Person jsonString) {

   Person person=personService.savedata(jsonString);
   return person;
}

@RequestBody - Covert Json object to java
@ResponseBody- convert Java object to json

make a header full screen (width) css

Live Demo

You can achieve the effect using a container element, then just set the containing elements margin to 0 auto and it will be centered.

Markup

<div id="header">
    <div id="headerContent">
        Header text
    </div>
</div>

CSS

#header{
    width:100%; 
    background: url(yourimage);
}
#headerContent{
    margin: 0 auto; width: 960px;
}

creating a new list with subset of list using index in python

Suppose

a = ['a', 'b', 'c', 3, 4, 'd', 6, 7, 8]

and the list of indexes is stored in

b= [0, 1, 2, 4, 6, 7, 8]

then a simple one-line solution will be

c = [a[i] for i in b]

Check if an object belongs to a class in Java

Try operator instanceof.

How can I clone a JavaScript object except for one key?

You also can use spread operator to do this

const source = { a: 1, b: 2, c: 3, z: 26 }
const copy = { ...source, ...{ b: undefined } } // { a: 1, c: 3, z: 26 }

What is a simple C or C++ TCP server and client example?

Although many year ago, clsocket seems a really nice small cross-platform (Windows, Linux, Mac OSX): https://github.com/DFHack/clsocket

Javascript select onchange='this.form.submit()'

You should be able to use something similar to:

$('#selectElementId').change(
    function(){
         $(this).closest('form').trigger('submit');
         /* or:
         $('#formElementId').trigger('submit');
            or:
         $('#formElementId').submit();
         */
    });

What does "Table does not support optimize, doing recreate + analyze instead" mean?

The better option is create a new table copy the rows to the destination table, drop the actual table and rename the newly created table . This method is good for small tables,

Sql Server : How to use an aggregate function like MAX in a WHERE clause

You could use a sub query...

WHERE t1.field3 = (SELECT MAX(st1.field3) FROM table1 AS st1)

But I would actually move this out of the where clause and into the join statement, as an AND for the ON clause.

Programs & Examples On #Roundedcorners dropshadow

How to show shadow around the linearlayout in Android?

Oracle row count of table by count(*) vs NUM_ROWS from DBA_TABLES

Add Keypair to existing EC2 instance

LINQ to SQL using GROUP BY and COUNT(DISTINCT)

Facebook Javascript SDK Problem: "FB is not defined"

How to use UIVisualEffectView to Blur Image?

<ng-container> vs <template>

Edit : Now it is documented

<ng-container> to the rescue

Original answer:

Import PEM into Java Key Store

Is it possible to insert HTML content in XML document?

How to force Hibernate to return dates as java.util.Date instead of Timestamp?

Access-control-allow-origin with multiple domains

How do I find a stored procedure containing <text>?

How to make a whole 'div' clickable in html and css without JavaScript?

Where is SQLite database stored on disk?

How can I check whether an array is null / empty?

How to click on hidden element in Selenium WebDriver?

"The given path's format is not supported."

Multiplying across in a numpy array

python setup.py uninstall

Database cluster and load balancing

What does FETCH_HEAD in Git mean?

How to concatenate columns in a Postgres SELECT?

With CSS, how do I make an image span the full width of the page as a background image?

Using Python Requests: Sessions, Cookies, and POST

How to check if running as root in a bash script

Optimized all-round solution for performance and reliability; all shells compatible

Benchmark (save to file is_user_root__benchmark)

Explanation

Why I post this solution after so many years the OP has asked

Portable POSIX solution + Example of usage of the above function

Conclusion

How to get the background color of an HTML element?

Insert picture/table in R Markdown

Update, 2019-Aug-31

I keep getting this error for my simple python program: "TypeError: 'float' object cannot be interpreted as an integer"

Replace words in a string - Ruby

psql: FATAL: Ident authentication failed for user "postgres"

Java Singleton and Synchronization

How can I fix MySQL error #1064?

TL;DR

Aaaagh!! What does #1064 mean?

What is this "syntax" of which you speak? Is it witchcraft?

What does that have to do with MySQL?

How do I fix it?

Read the message!

Examine the actual text of your command!

Obey orders!

A note of reservation

Form Submit Execute JavaScript Best Practice?

laravel 5.3 new Auth::routes()

select and echo a single field from mysql db using PHP

Merging Cells in Excel using C#

insert data into database with codeigniter

Python Iterate Dictionary by Index

How do I make Java register a string input with spaces?

Text not wrapping in p tag

trace a particular IP and port

openpyxl - adjust column width size

How to setup FTP on xampp

BULK INSERT with identity (auto-increment) column

How do you install Boost on MacOS?

Altering a column to be nullable

OpenVPN failed connection / All TAP-Win32 adapters on this system are currently in use

OSError: [Errno 2] No such file or directory while using python subprocess in Django

Cannot lower case button text in android studio

How to do a GitHub pull request

How to compare the contents of two string objects in PowerShell

Rotating videos with FFmpeg

WebSockets protocol vs HTTP

What is href="#" and why is it used?

difference between throw and throw new Exception()

Numpy - Replace a number with NaN

error: use of deleted function

Best way to randomize an array with .NET

Html.DropDownList - Disabled/Readonly

css transform, jagged edges in chrome

`<ng-container>` to the rescue

Benchmark (save to file `is_user_root__benchmark`)

`java.time` Details

Do I really need to encode '&' as '&'?