Programs & Examples On #File properties

Java: recommended solution for deep cloning/copying an instance

I'd recommend the DIY way which, combined with a good hashCode() and equals() method should be easy to proof in a unit test.

How do I convert a number to a numeric, comma-separated formatted string?

I looked at several of the options. Here are my two favorites, because I needed to round the value.

,DataSizeKB = replace(convert(varchar,Cast(Round(SUM(BigNbr / 0.128),0)as money),1), '.00','')
,DataSizeKB2   = format(Round(SUM(BigNbr / 0.128),0),'##,##0')
-----------------
--- below if the full script where I left DataSizeKB in both methods -----------
--- enjoy --------- 
--- Hank Freeman : [email protected] 
-----------------------------------
--- Scritp to get rowcounts and Memory size of index and Primary Keys
   SELECT
   FileGroupName = DS.name
   ,FileGroupType =
      CASE DS.[type]
        WHEN 'FG' THEN 'Filegroup'
        WHEN 'FD' THEN 'Filestream'
        WHEN 'FX' THEN 'Memory-optimized'
        WHEN 'PS' THEN 'Partition Scheme'
        ELSE 'Unknown'
      END
   ,SchemaName = SCH.name
   ,TableName = OBJ.name
   ,IndexType =
      CASE IDX.[type]
        WHEN 0 THEN 'Heap'
        WHEN 1 THEN 'Clustered'
        WHEN 2 THEN 'Nonclustered'
        WHEN 3 THEN 'XML'
        WHEN 4 THEN 'Spatial'
        WHEN 5 THEN 'Clustered columnstore'
        WHEN 6 THEN 'Nonclustered columnstore'
        WHEN 7 THEN 'Nonclustered hash'
      END
   ,IndexName = IDX.name
   ,RowCounts = replace(convert(varchar,Cast(p.rows as money),1), '.00','')  --- MUST show for all types when no Primary key
   --,( Case WHEN IDX.[type] IN (2,6,7) then 0  else  p.rows  end )as Rowcounts_T
   ,AllocationDesc = AU.type_desc
/*
   ,RowCounts = p.rows  --- MUST show for all types when no Primary key
   ,TotalSizeKB2  = Cast(Round(SUM(AU.total_pages / 0.128),0)as int) -- 128 pages per megabyte
   ,UsedSizeKB    = Cast(Round(SUM(AU.used_pages / 0.128),0)as int) 
   ,DataSizeKB    = Cast(Round(SUM(AU.data_pages / 0.128),0)as int)
    --replace(convert(varchar,cast(1234567 as money),1), '.00','')
*/
   ,TotalSizeKB   = replace(convert(varchar,Cast(Round(SUM(AU.total_pages / 0.128),0)as money),1), '.00','') -- 128 pages per megabyte
   ,UsedSizeKB    = replace(convert(varchar,Cast(Round(SUM(AU.used_pages / 0.128),0)as money),1), '.00','') 
   ,DataSizeKB    = replace(convert(varchar,Cast(Round(SUM(AU.data_pages / 0.128),0)as money),1), '.00','')
   ,DataSizeKB2   = format(Round(SUM(AU.data_pages / 0.128),0),'##,##0')
   ,DataSizeKB3   = format(SUM(AU.data_pages / 0.128),'##,##0')
   --SELECT Format(1234567.8, '##,##0.00')
   ---
   ,is_default    = CONVERT(INT,DS.is_default)
   ,is_read_only = CONVERT(INT,DS.is_read_only)
  FROM
   sys.filegroups DS -- you could also use sys.data_spaces
    LEFT JOIN sys.allocation_units AU ON DS.data_space_id = AU.data_space_id
    LEFT JOIN sys.partitions PA
      ON (AU.[type] IN (1,3) AND
          AU.container_id = PA.hobt_id) OR
         (AU.[type] = 2 AND
          AU.container_id = PA.[partition_id])
    LEFT JOIN sys.objects OBJ ON PA.[object_id] = OBJ.[object_id]
    LEFT JOIN sys.schemas SCH ON OBJ.[schema_id] = SCH.[schema_id]
    LEFT JOIN sys.indexes IDX
      ON PA.[object_id] = IDX.[object_id] AND
         PA.index_id = IDX.index_id
    -----
    INNER JOIN 
      sys.partitions p ON obj.object_id = p.OBJECT_ID AND IDX.index_id = p.index_id
  WHERE
    OBJ.type_desc = 'USER_TABLE' -- only include user tables
    OR
    DS.[type] = 'FD' -- or the filestream filegroup
  GROUP BY
    DS.name ,SCH.name ,OBJ.name ,IDX.[type] ,IDX.name ,DS.[type]  ,DS.is_default   ,DS.is_read_only -- discard different allocation units
   ,p.rows  ,AU.type_desc  --- 
  ORDER BY
    DS.name ,SCH.name ,OBJ.name ,IDX.name
   ---
   ;

Regular expression to validate US phone numbers?

The easiest way to match both

^\([0-9]{3}\)[0-9]{3}-[0-9]{4}$

and

^[0-9]{3}-[0-9]{3}-[0-9]{4}$

is to use alternation ((...|...)): specify them as two mostly-separate options:

^(\([0-9]{3}\)|[0-9]{3}-)[0-9]{3}-[0-9]{4}$

By the way, when Americans put the area code in parentheses, we actually put a space after that; for example, I'd write (123) 123-1234, not (123)123-1234. So you might want to write:

^(\([0-9]{3}\) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$

(Though it's probably best to explicitly demonstrate the format that you expect phone numbers to be in.)

How to playback MKV video in web browser?

<video controls width=800 autoplay>
    <source src="file path here">
</video>

This will display the video (.mkv) using Google Chrome browser only.

How npm start runs a server on port 8000

To change the port

npm start --port 8000

How to get the current TimeStamp?

Since Qt 5.8, we now have QDateTime::currentSecsSinceEpoch() to deliver the seconds directly, a.k.a. as real Unix timestamp. So, no need to divide the result by 1000 to get seconds anymore.

Credits: also posted as comment to this answer. However, I think it is easier to find if it is a separate answer.

Permission denied: /var/www/abc/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable?

I have also got stuck into this and believe me disabling SELinux is not a good idea.

Please just use below and you are good,

sudo restorecon -R /var/www/mysite

Enjoy..

Parsing a comma-delimited std::string

You could also use the following function.

void tokenize(const string& str, vector<string>& tokens, const string& delimiters = ",")
{
  // Skip delimiters at beginning.
  string::size_type lastPos = str.find_first_not_of(delimiters, 0);

  // Find first non-delimiter.
  string::size_type pos = str.find_first_of(delimiters, lastPos);

  while (string::npos != pos || string::npos != lastPos) {
    // Found a token, add it to the vector.
    tokens.push_back(str.substr(lastPos, pos - lastPos));

    // Skip delimiters.
    lastPos = str.find_first_not_of(delimiters, pos);

    // Find next non-delimiter.
    pos = str.find_first_of(delimiters, lastPos);
  }
}

How do I setup the InternetExplorerDriver so it works

Unpack it and place somewhere you can find it. In my example, I will assume you will place it to C:\Selenium\iexploredriver.exe

Then you have to set it up in the system. Here is the Java code pasted from my Selenium project:

File file = new File("C:/Selenium/iexploredriver.exe");
System.setProperty("webdriver.ie.driver", file.getAbsolutePath());
WebDriver driver = new InternetExplorerDriver();

Basically, you have to set this property before you initialize driver

Reference:

what happens when you type in a URL in browser

Attention: this is an extremely rough and oversimplified sketch, assuming the simplest possible HTTP request (no HTTPS, no HTTP2, no extras), simplest possible DNS, no proxies, single-stack IPv4, one HTTP request only, a simple HTTP server on the other end, and no problems in any step. This is, for most contemporary intents and purposes, an unrealistic scenario; all of these are far more complex in actual use, and the tech stack has become an order of magnitude more complicated since this was written. With this in mind, the following timeline is still somewhat valid:

  1. browser checks cache; if requested object is in cache and is fresh, skip to #9
  2. browser asks OS for server's IP address
  3. OS makes a DNS lookup and replies the IP address to the browser
  4. browser opens a TCP connection to server (this step is much more complex with HTTPS)
  5. browser sends the HTTP request through TCP connection
  6. browser receives HTTP response and may close the TCP connection, or reuse it for another request
  7. browser checks if the response is a redirect or a conditional response (3xx result status codes), authorization request (401), error (4xx and 5xx), etc.; these are handled differently from normal responses (2xx)
  8. if cacheable, response is stored in cache
  9. browser decodes response (e.g. if it's gzipped)
  10. browser determines what to do with response (e.g. is it a HTML page, is it an image, is it a sound clip?)
  11. browser renders response, or offers a download dialog for unrecognized types

Again, discussion of each of these points have filled countless pages; take this only as a summary, abridged for the sake of clarity. Also, there are many other things happening in parallel to this (processing typed-in address, speculative prefetching, adding page to browser history, displaying progress to user, notifying plugins and extensions, rendering the page while it's downloading, pipelining, connection tracking for keep-alive, cookie management, checking for malicious content etc.) - and the whole operation gets an order of magnitude more complex with HTTPS (certificates and ciphers and pinning, oh my!).

Spring Boot Program cannot find main class

I also got this error, was not having any clue. I could see the class and jars in Target folder. I later installed Maven 3.5, switched my local repo from C drive to other drive through conf/settings.xml of Maven. It worked perfectly fine after that. I think having local repo in C drive was main issue. Even though repo was having full access.

Listen for key press in .NET console app

The shortest way:

Console.WriteLine("Press ESC to stop");

while (!(Console.KeyAvailable && Console.ReadKey(true).Key == ConsoleKey.Escape))
{
    // do something
}

Console.ReadKey() is a blocking function, it stops the execution of the program and waits for a key press, but thanks to checking Console.KeyAvailable first, the while loop is not blocked, but running until the Esc is pressed.

How do you subtract Dates in Java?

Well you can remove the third calendar instance.

GregorianCalendar c1 = new GregorianCalendar();
GregorianCalendar c2 = new GregorianCalendar();
c1.set(2000, 1, 1);
c2.set(2010,1, 1);
c2.add(GregorianCalendar.MILLISECOND, -1 * c1.getTimeInMillis());

Magento: Set LIMIT on collection

The way to do was looking at the code in code/core/Mage/Catalog/Model/Resource/Category/Flat/Collection.php at line 380 in Magento 1.7.2 on the function setPage($pageNum, $pageSize)

 $collection = Mage::getModel('model')
     ->getCollection()
     ->setCurPage(2) // 2nd page
     ->setPageSize(10); // 10 elements per pages

I hope this will help someone.

How to merge a specific commit in Git

We will have to use git cherry-pick <commit-number>

Scenario: I am on a branch called release and I want to add only few changes from master branch to release branch.

Step 1: checkout the branch where you want to add the changes

git checkout release

Step 2: get the commit number of the changes u want to add

for example

git cherry-pick 634af7b56ec

Step 3: git push

Note: Every time your merge there is a separate commit number create. Do not take the commit number for merge that won't work. Instead, the commit number for any regular commit u want to add.

How to get 30 days prior to current date?

This is an ES6 version

let date = new Date()
let newDate = new Date(date.setDate(date.getDate()-30))
console.log(newDate.getMonth()+1 + '/' + newDate.getDate() + '/' + newDate.getFullYear() )

Writing your own square root function

// Fastest way I found, an (extreme) C# unrolled version of:
// http://www.hackersdelight.org/hdcodetxt/isqrt.c.txt         (isqrt4)

// It's quite a lot of code, basically a binary search (the "if" statements)
// followed by an unrolled loop (the labels).
// Most important: it's fast, twice as fast as "Math.Sqrt".
// On my pc: Math.Sqrt ~35 ns, sqrt <16 ns (mean <14 ns)

private static uint sqrt(uint x)
{
    uint y, z;
    if (x < 1u << 16)
    {
        if (x < 1u << 08)
        {
            if (x < 1u << 04) return x < 1u << 02 ? x + 3u >> 2 : x + 15u >> 3;
            else
            {
                if (x < 1u << 06)
                { y = 1u << 03; x -= 1u << 04; if (x >= 5u << 02) { x -= 5u << 02; y |= 1u << 02; } goto L0; }
                else
                { y = 1u << 05; x -= 1u << 06; if (x >= 5u << 04) { x -= 5u << 04; y |= 1u << 04; } goto L1; }
            }
        }
        else                                             // slower (on my pc): .... y = 3u << 04; } goto L1; }
        {
            if (x < 1u << 12)
            {
                if (x < 1u << 10)
                { y = 1u << 07; x -= 1u << 08; if (x >= 5u << 06) { x -= 5u << 06; y |= 1u << 06; } goto L2; }
                else
                { y = 1u << 09; x -= 1u << 10; if (x >= 5u << 08) { x -= 5u << 08; y |= 1u << 08; } goto L3; }
            }
            else
            {
                if (x < 1u << 14)
                { y = 1u << 11; x -= 1u << 12; if (x >= 5u << 10) { x -= 5u << 10; y |= 1u << 10; } goto L4; }
                else
                { y = 1u << 13; x -= 1u << 14; if (x >= 5u << 12) { x -= 5u << 12; y |= 1u << 12; } goto L5; }
            }
        }
    }
    else
    {
        if (x < 1u << 24)
        {
            if (x < 1u << 20)
            {
                if (x < 1u << 18)
                { y = 1u << 15; x -= 1u << 16; if (x >= 5u << 14) { x -= 5u << 14; y |= 1u << 14; } goto L6; }
                else
                { y = 1u << 17; x -= 1u << 18; if (x >= 5u << 16) { x -= 5u << 16; y |= 1u << 16; } goto L7; }
            }
            else
            {
                if (x < 1u << 22)
                { y = 1u << 19; x -= 1u << 20; if (x >= 5u << 18) { x -= 5u << 18; y |= 1u << 18; } goto L8; }
                else
                { y = 1u << 21; x -= 1u << 22; if (x >= 5u << 20) { x -= 5u << 20; y |= 1u << 20; } goto L9; }
            }
        }
        else
        {
            if (x < 1u << 28)
            {
                if (x < 1u << 26)
                { y = 1u << 23; x -= 1u << 24; if (x >= 5u << 22) { x -= 5u << 22; y |= 1u << 22; } goto La; }
                else
                { y = 1u << 25; x -= 1u << 26; if (x >= 5u << 24) { x -= 5u << 24; y |= 1u << 24; } goto Lb; }
            }
            else
            {
                if (x < 1u << 30)
                { y = 1u << 27; x -= 1u << 28; if (x >= 5u << 26) { x -= 5u << 26; y |= 1u << 26; } goto Lc; }
                else
                { y = 1u << 29; x -= 1u << 30; if (x >= 5u << 28) { x -= 5u << 28; y |= 1u << 28; } }
            }
        }
    }
    z = y | 1u << 26; y /= 2; if (x >= z) { x -= z; y |= 1u << 26; }
Lc: z = y | 1u << 24; y /= 2; if (x >= z) { x -= z; y |= 1u << 24; }
Lb: z = y | 1u << 22; y /= 2; if (x >= z) { x -= z; y |= 1u << 22; }
La: z = y | 1u << 20; y /= 2; if (x >= z) { x -= z; y |= 1u << 20; }
L9: z = y | 1u << 18; y /= 2; if (x >= z) { x -= z; y |= 1u << 18; }
L8: z = y | 1u << 16; y /= 2; if (x >= z) { x -= z; y |= 1u << 16; }
L7: z = y | 1u << 14; y /= 2; if (x >= z) { x -= z; y |= 1u << 14; }
L6: z = y | 1u << 12; y /= 2; if (x >= z) { x -= z; y |= 1u << 12; }
L5: z = y | 1u << 10; y /= 2; if (x >= z) { x -= z; y |= 1u << 10; }
L4: z = y | 1u << 08; y /= 2; if (x >= z) { x -= z; y |= 1u << 08; }
L3: z = y | 1u << 06; y /= 2; if (x >= z) { x -= z; y |= 1u << 06; }
L2: z = y | 1u << 04; y /= 2; if (x >= z) { x -= z; y |= 1u << 04; }
L1: z = y | 1u << 02; y /= 2; if (x >= z) { x -= z; y |= 1u << 02; }
L0: return x > y ? y / 2 | 1u : y / 2;
}

Python not working in the command line of git bash

I am windows 10 user and I have installed GIT in my system by just accepting the defaults.

After reading the above answers, I got 2 solutions for my own and these 2 solutions perfectly works on GIT bash and facilitates me to execute Python statements on GIT bash.

I am attaching 3 images of my GIT bash terminal. 1st with problem and the latter 2 as solutions.

PROBLEM - Cursor is just waiting after hitting python command

enter image description here

SOLUTION 1

Execute winpty <path-to-python-installation-dir>/python.exe on GIT bash terminal.

Note: Do not use C:\Users\Admin like path style in GIT bash, instead use /C/Users/Admin.

In my case, I executed winpty /C/Users/SJV/Anaconda2/python.exe command on GIT bash

Or if you do not know your username then execute winpty /C/Users/$USERNAME/Anaconda2/python.exe

enter image description here

SOLUTION 2

Just type python -i and that is it.

enter image description here

Thanks.

How do I create a user account for basic authentication?

I was able to achieve Basic Authentication on Windows Server 2012 doing the following:

Select your site within IIS and choose Authentication enter image description here

Ensure Basic Authentication is the only enabled option enter image description here

THEN! Add a username and password via the Server Manager. Select Tools -> Computer Management enter image description here

Under System Tools -> Local Users and Groups -> Users right-click anywhere in the middle pane, choose New User.. then fill in the credentials you want to use. enter image description here

Now when you navigate to the site in the browser you should get prompted with an authentication dialog:

enter image description here

private final static attribute vs private final attribute

If you mark this variable static then as you know, you would be requiring static methods to again access these values,this will be useful if you already think of using these variables only in static methods. If this is so then this would be the best one.

You can however make the variable now as public since no one can modify it just like "System.out", it again depends upon your intentions and what you want to achieve.

Automatically enter SSH password with script

Use public key authentication: https://help.ubuntu.com/community/SSH/OpenSSH/Keys

In the source host run this only once:

ssh-keygen -t rsa # ENTER to every field
ssh-copy-id myname@somehost

That's all, after that you'll be able to do ssh without password.

IndexError: list index out of range and python

Always keep in mind when you want to overcome this error, the default value of indexing and range starts from 0, so if total items is 100 then l[99] and range(99) will give you access up to the last element.

whenever you get this type of error please cross check with items that comes between/middle in range, and insure that their index is not last if you get output then you have made perfect error that mentioned above.

Converting list to *args when calling function

yes, using *arg passing args to a function will make python unpack the values in arg and pass it to the function.

so:

>>> def printer(*args):
 print args


>>> printer(2,3,4)
(2, 3, 4)
>>> printer(*range(2, 5))
(2, 3, 4)
>>> printer(range(2, 5))
([2, 3, 4],)
>>> 

find first sequence item that matches a criterion

If you don't have any other indexes or sorted information for your objects, then you will have to iterate until such an object is found:

next(obj for obj in objs if obj.val == 5)

This is however faster than a complete list comprehension. Compare these two:

[i for i in xrange(100000) if i == 1000][0]

next(i for i in xrange(100000) if i == 1000)

The first one needs 5.75ms, the second one 58.3µs (100 times faster because the loop 100 times shorter).

Difference between jQuery parent(), parents() and closest() functions

$(this).closest('div') is same as $(this).parents('div').eq(0).

How to print a percentage value in python?

Just for the sake of completeness, since I noticed no one suggested this simple approach:

>>> print("%.0f%%" % (100 * 1.0/3))
33%

Details:

  • %.0f stands for "print a float with 0 decimal places", so %.2f would print 33.33
  • %% prints a literal %. A bit cleaner than your original +'%'
  • 1.0 instead of 1 takes care of coercing the division to float, so no more 0.0

Dynamic type languages versus static type languages

Perhaps the single biggest "benefit" of dynamic typing is the shallower learning curve. There is no type system to learn and no non-trivial syntax for corner cases such as type constraints. That makes dynamic typing accessible to a lot more people and feasible for many people for whom sophisticated static type systems are out of reach. Consequently, dynamic typing has caught on in the contexts of education (e.g. Scheme/Python at MIT) and domain-specific languages for non-programmers (e.g. Mathematica). Dynamic languages have also caught on in niches where they have little or no competition (e.g. Javascript).

The most concise dynamically-typed languages (e.g. Perl, APL, J, K, Mathematica) are domain specific and can be significantly more concise than the most concise general-purpose statically-typed languages (e.g. OCaml) in the niches they were designed for.

The main disadvantages of dynamic typing are:

  • Run-time type errors.

  • Can be very difficult or even practically impossible to achieve the same level of correctness and requires vastly more testing.

  • No compiler-verified documentation.

  • Poor performance (usually at run-time but sometimes at compile time instead, e.g. Stalin Scheme) and unpredictable performance due to dependence upon sophisticated optimizations.

Personally, I grew up on dynamic languages but wouldn't touch them with a 40' pole as a professional unless there were no other viable options.

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

I've managed to bind a custom model to an element at runtime. The code is here: http://jsfiddle.net/ZiglioNZ/tzD4T/457/

The interesting bit is that I apply the data-bind attribute to an element I didn't define:

    var handle = slider.slider().find(".ui-slider-handle").first();
    $(handle).attr("data-bind", "tooltip: viewModel.value");
    ko.applyBindings(viewModel.value, $(handle)[0]);

Repeat command automatically in Linux

If you want to avoid "drifting", meaning you want the command to execute every N seconds regardless of how long the command takes (assuming it takes less than N seconds), here's some bash that will repeat a command every 5 seconds with one-second accuracy (and will print out a warning if it can't keep up):

PERIOD=5

while [ 1 ]
do
    let lastup=`date +%s`
    # do command
    let diff=`date +%s`-$lastup
    if [ "$diff" -lt "$PERIOD" ]
    then
        sleep $(($PERIOD-$diff))
    elif [ "$diff" -gt "$PERIOD" ]
    then
        echo "Command took longer than iteration period of $PERIOD seconds!"
    fi
done

It may still drift a little since the sleep is only accurate to one second. You could improve this accuracy by creative use of the date command.

Scroll back to the top of scrollable div

2020 UPDATE

You can use .scroll() to easily scroll elements or window. It has a built-in smooth scroll effect so basically the code couldn't be simpler.

Standard properties:

var options = {
    top:       0,        // Number of pixels along the Y axis to scroll the window or element
    left:      0,        // Number of pixels along the X axis to scroll the window or element.
    behavior:  'smooth'  // ('smooth'|'auto') - animate smoothly, or move in a single jump
}

DOCS: https://developer.mozilla.org/en-US/docs/Web/API/Window/scroll

SEE ALSO: .scrollIntoView() https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView


DEMO:

_x000D_
_x000D_
document.getElementById('btn').addEventListener('click',function(){

  document.getElementById('container').scroll({top:0,behavior:'smooth'});
  
});
_x000D_
/*DEMO*/
#container{
  width:300px;
  max-height:300px;
  padding:1rem;
  margin-left:auto;
  margin-right:auto;
  background-color:#222;
  color:#ccc;
  text-align:justify;
  overflow-y:auto;
}
#btn{
  width:100%;
  margin-top:1rem;
}
_x000D_
<div id="container">
  <div>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</div>
  <button id="btn">Scroll to top</button>
</div>
_x000D_
_x000D_
_x000D_

Send a file via HTTP POST with C#

     public string SendFile(string filePath)
            {
                WebResponse response = null;
                try
                {
                    string sWebAddress = "Https://www.address.com";

                    string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
                    byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
                    HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(sWebAddress);
                    wr.ContentType = "multipart/form-data; boundary=" + boundary;
                    wr.Method = "POST";
                    wr.KeepAlive = true;
                    wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
                    Stream stream = wr.GetRequestStream();
                    string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";

                    stream.Write(boundarybytes, 0, boundarybytes.Length);
                    byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(filePath);
                    stream.Write(formitembytes, 0, formitembytes.Length);
                    stream.Write(boundarybytes, 0, boundarybytes.Length);
                    string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
                    string header = string.Format(headerTemplate, "file", Path.GetFileName(filePath), Path.GetExtension(filePath));
                    byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
                    stream.Write(headerbytes, 0, headerbytes.Length);

                    FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
                    byte[] buffer = new byte[4096];
                    int bytesRead = 0;
                    while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                        stream.Write(buffer, 0, bytesRead);
                    fileStream.Close();

                    byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
                    stream.Write(trailer, 0, trailer.Length);
                    stream.Close();

                    response = wr.GetResponse();
                    Stream responseStream = response.GetResponseStream();
                    StreamReader streamReader = new StreamReader(responseStream);
                    string responseData = streamReader.ReadToEnd();
                    return responseData;
                }
                catch (Exception ex)
                {
                    return ex.Message;
                }
                finally
                {
                    if (response != null)
                        response.Close();
                }
            }

How to get the absolute coordinates of a view

You can get a View's coordinates using getLocationOnScreen() or getLocationInWindow()

Afterwards, x and y should be the top-left corner of the view. If your root layout is smaller than the screen (like in a Dialog), using getLocationInWindow will be relative to its container, not the entire screen.

Java Solution

int[] point = new int[2];
view.getLocationOnScreen(point); // or getLocationInWindow(point)
int x = point[0];
int y = point[1];

NOTE: If value is always 0, you are likely changing the view immediately before requesting location.

To ensure view has had a chance to update, run your location request after the View's new layout has been calculated by using view.post:

view.post(() -> {
    // Values should no longer be 0
    int[] point = new int[2];
    view.getLocationOnScreen(point); // or getLocationInWindow(point)
    int x = point[0];
    int y = point[1];
});

~~

Kotlin Solution

val point = IntArray(2)
view.getLocationOnScreen(point) // or getLocationInWindow(point)
val (x, y) = point

NOTE: If value is always 0, you are likely changing the view immediately before requesting location.

To ensure view has had a chance to update, run your location request after the View's new layout has been calculated by using view.post:

view.post {
    // Values should no longer be 0
    val point = IntArray(2)
    view.getLocationOnScreen(point) // or getLocationInWindow(point)
    val (x, y) = point
}

I recommend creating an extension function for handling this:

// To use, call:
val (x, y) = view.screenLocation

val View.screenLocation get(): IntArray {
    val point = IntArray(2)
    getLocationOnScreen(point)
    return point
}

And if you require reliability, also add:

view.screenLocationSafe { x, y -> Log.d("", "Use $x and $y here") }

fun View.screenLocationSafe(callback: (Int, Int) -> Unit) {
    post {
        val (x, y) = screenLocation
        callback(x, y)
    }
}

Getting CheckBoxList Item values

to get the items checked you can use CheckedItems or GetItemsChecked. I tried below code in .NET 4.5

Iterate through the CheckedItems collection. This will give you the item number in the list of checked items, not the overall list. So if the first item in the list is not checked and the second item is checked, the code below will display text like Checked Item 1 = MyListItem2.

//Determine if there are any items checked. 
if(chBoxListTables.CheckedItems.Count != 0)  
{
    //looped through all checked items and show results.
    string s = "";
    for (int x = 0; x < chBoxListTables.CheckedItems.Count; x++)
    {
        s = s + (x + 1).ToString() + " = " + chBoxListTables.CheckedItems[x].ToString()+ ", ";
    }
    MessageBox.Show(s);//show result
}

-OR-

Step through the Items collection and call the GetItemChecked method for each item. This will give you the item number in the overall list, so if the first item in the list is not checked and the second item is checked, it will display something like Item 2 = MyListItem2.

int i;  
string s;   
s = "Checked items:\n" ;  
for (i = 0; i < checkedListBox1.Items.Count; i++)  
{  
   if (checkedListBox1.GetItemChecked(i))  
   {  
      s = s + "Item " + (i+1).ToString() + " = " + checkedListBox1.Items[i].ToString() + "\n";  
   }  
}  
MessageBox.Show (s);

Hope this helps...

Jackson JSON custom serialization for certain fields

with the help of @JsonView we can decide fields of model classes to serialize which satisfy the minimal criteria ( we have to define the criteria) like we can have one core class with 10 properties but only 5 properties can be serialize which are needful for client only

Define our Views by simply creating following class:

public class Views
{
    static class Android{};
    static class IOS{};
    static class Web{};
}

Annotated model class with views:

public class Demo 
{
    public Demo() 
    {
    }

@JsonView(Views.IOS.class)
private String iosField;

@JsonView(Views.Android.class)
private String androidField;

@JsonView(Views.Web.class)
private String webField;

 // getters/setters
...
..
}

Now we have to write custom json converter by simply extending HttpMessageConverter class from spring as:

    public class CustomJacksonConverter implements HttpMessageConverter<Object> 
    {
    public CustomJacksonConverter() 
        {
            super();
        //this.delegate.getObjectMapper().setConfig(this.delegate.getObjectMapper().getSerializationConfig().withView(Views.ClientView.class));
        this.delegate.getObjectMapper().configure(MapperFeature.DEFAULT_VIEW_INCLUSION, true);
        this.delegate.getObjectMapper().setSerializationInclusion(Include.NON_NULL);

    }

    // a real message converter that will respond to methods and do the actual work
    private MappingJackson2HttpMessageConverter delegate = new MappingJackson2HttpMessageConverter();

    @Override
    public boolean canRead(Class<?> clazz, MediaType mediaType) {
        return delegate.canRead(clazz, mediaType);
    }

    @Override
    public boolean canWrite(Class<?> clazz, MediaType mediaType) {
        return delegate.canWrite(clazz, mediaType);
    }

    @Override
    public List<MediaType> getSupportedMediaTypes() {
        return delegate.getSupportedMediaTypes();
    }

    @Override
    public Object read(Class<? extends Object> clazz,
            HttpInputMessage inputMessage) throws IOException,
            HttpMessageNotReadableException {
        return delegate.read(clazz, inputMessage);
    }

    @Override
    public void write(Object obj, MediaType contentType, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException 
    {
        synchronized(this) 
        {
            String userAgent = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest().getHeader("userAgent");
            if ( userAgent != null ) 
            {
                switch (userAgent) 
                {
                case "IOS" :
                    this.delegate.getObjectMapper().setConfig(this.delegate.getObjectMapper().getSerializationConfig().withView(Views.IOS.class));
                    break;
                case "Android" :
                    this.delegate.getObjectMapper().setConfig(this.delegate.getObjectMapper().getSerializationConfig().withView(Views.Android.class));
                    break;
                case "Web" :
                    this.delegate.getObjectMapper().setConfig(this.delegate.getObjectMapper().getSerializationConfig().withView( Views.Web.class));
                    break;
                default:
                    this.delegate.getObjectMapper().setConfig(this.delegate.getObjectMapper().getSerializationConfig().withView( null ));
                    break;
                }
            }
            else
            {
                // reset to default view
                this.delegate.getObjectMapper().setConfig(this.delegate.getObjectMapper().getSerializationConfig().withView( null ));
            }
            delegate.write(obj, contentType, outputMessage);
        }
    }

}

Now there is need to tell spring to use this custom json convert by simply putting this in dispatcher-servlet.xml

<mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean id="jsonConverter" class="com.mactores.org.CustomJacksonConverter" >
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

That's how you will able to decide which fields to get serialize.

How to directly execute SQL query in C#?

IMPORTANT NOTE: You should not concatenate SQL queries unless you trust the user completely. Query concatenation involves risk of SQL Injection being used to take over the world, ...khem, your database.

If you don't want to go into details how to execute query using SqlCommand then you could call the same command line like this:

string userInput = "Brian";
var process = new Process();
var startInfo = new ProcessStartInfo();
startInfo.WindowStyle = ProcessWindowStyle.Hidden;
startInfo.FileName = "cmd.exe";
startInfo.Arguments = string.Format(@"sqlcmd.exe -S .\PDATA_SQLEXPRESS -U sa -P 2BeChanged! -d PDATA_SQLEXPRESS  
     -s ; -W -w 100 -Q "" SELECT tPatCulIntPatIDPk, tPatSFirstname, tPatSName,
     tPatDBirthday  FROM  [dbo].[TPatientRaw] WHERE tPatSName = '{0}' """, userInput);

process.StartInfo = startInfo;
process.Start();

Just ensure that you escape each double quote " with ""

Adding options to a <select> using jQuery?

Try

mySelect.innerHTML+= '<option value=1>My option</option>';

_x000D_
_x000D_
btn.onclick= _=> mySelect.innerHTML+= `<option selected>${+new Date}</option>`
_x000D_
<button id="btn">Add option</button>

<select id="mySelect"></select>
_x000D_
_x000D_
_x000D_

check if file exists in php

file_exists checks whether a file exist in the specified path or not.

Syntax:

file_exists ( string $filename )

Returns TRUE if the file or directory specified by filename exists; FALSE otherwise.

$filename = BASE_DIR."images/a/test.jpg";
if (file_exists($filename)){
    echo "File exist.";
}else{
    echo "File does not exist.";
}

Another alternative method you can use getimagesize(), it will return 0(zero) if file/directory is not available in the specified path.

if (@getimagesize($filename)) {...}

JavaScript ternary operator example with functions

There is nothing particularly tricky about the example you posted.

In a ternary operator, the first argument (the conditional) is evaluated and if the result is true, the second argument is evaluated and returned, otherwise, the third is evaluated and returned. Each of those arguments can be any valid code block, including function calls.

Think of it this way:

var x = (1 < 2) ? true : false;

Could also be written as:

var x = (1 < 2) ? getTrueValue() : getFalseValue();

This is perfectly valid, and those functions can contain any arbitrary code, whether it is related to returning a value or not. Additionally, the results of the ternary operation don't have to be assigned to anything, just as function results do not have to be assigned to anything:

(1 < 2) ? getTrueValue() : getFalseValue();

Now simply replace those with any arbitrary functions, and you are left with something like your example:

(1 < 2) ? removeItem($this) : addItem($this);

Now your last example really doesn't need a ternary at all, as it can be written like this:

x = (1 < 2);  // x will be set to "true"

A TypeScript GUID class?

There is an implementation in my TypeScript utilities based on JavaScript GUID generators.

Here is the code:

_x000D_
_x000D_
class Guid {_x000D_
  static newGuid() {_x000D_
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {_x000D_
      var r = Math.random() * 16 | 0,_x000D_
        v = c == 'x' ? r : (r & 0x3 | 0x8);_x000D_
      return v.toString(16);_x000D_
    });_x000D_
  }_x000D_
}_x000D_
_x000D_
// Example of a bunch of GUIDs_x000D_
for (var i = 0; i < 100; i++) {_x000D_
  var id = Guid.newGuid();_x000D_
  console.log(id);_x000D_
}
_x000D_
_x000D_
_x000D_

Please note the following:

C# GUIDs are guaranteed to be unique. This solution is very likely to be unique. There is a huge gap between "very likely" and "guaranteed" and you don't want to fall through this gap.

JavaScript-generated GUIDs are great to use as a temporary key that you use while waiting for a server to respond, but I wouldn't necessarily trust them as the primary key in a database. If you are going to rely on a JavaScript-generated GUID, I would be tempted to check a register each time a GUID is created to ensure you haven't got a duplicate (an issue that has come up in the Chrome browser in some cases).

Print multiple arguments in Python

In Python 3.6, f-string is much cleaner.

In earlier version:

print("Total score for %s is %s. " % (name, score))

In Python 3.6:

print(f'Total score for {name} is {score}.')

will do.

It is more efficient and elegant.

"detached entity passed to persist error" with JPA/EJB code

ERD

Let's say you have two entities Album and Photo. Album contains many photos, so it's a one to many relationship.

Album class

@Entity
public class Album {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    Integer albumId;

    String albumName;

    @OneToMany(targetEntity=Photo.class,mappedBy="album",cascade={CascadeType.ALL},orphanRemoval=true)
    Set<Photo> photos = new HashSet<Photo>();
}

Photo class

@Entity
public class Photo{
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    Integer photo_id;

    String photoName;

    @ManyToOne(targetEntity=Album.class)
    @JoinColumn(name="album_id")
    Album album;

}

What you have to do before persist or merge is to set the Album reference in each photos.

        Album myAlbum = new Album();
        Photo photo1 = new Photo();
        Photo photo2 = new Photo();

        photo1.setAlbum(myAlbum);
        photo2.setAlbum(myAlbum);       

That is how to attach the related entity before you persist or merge.

How to delete all files from a specific folder?

Add the following namespace,

using System.IO;

and use the Directory class to reach on the specific folder:

string[] fileNames = Directory.GetFiles(@"your directory path");
foreach (string fileName in fileNames)
    File.Delete(fileName);

How to open the default webbrowser using java

I recast Brajesh Kumar's answer above into Clojure as follows:

(defn open-browser 
  "Open a new browser (window or tab) viewing the document at this `uri`."
  [uri]
  (if (java.awt.Desktop/isDesktopSupported)
    (let [desktop (java.awt.Desktop/getDesktop)]
      (.browse desktop (java.net.URI. uri)))
    (let [rt (java.lang.Runtime/getRuntime)]
      (.exec rt (str "xdg-open " uri)))))

in case it's useful to anyone.

Java : Sort integer array without using Arrays.sort()

int[] arr = {111, 111, 110, 101, 101, 102, 115, 112};

/* for ascending order */

System.out.println(Arrays.toString(getSortedArray(arr)));
/*for descending order */
System.out.println(Arrays.toString(getSortedArray(arr)));

private int[] getSortedArray(int[] k){  

        int localIndex =0;
        for(int l=1;l<k.length;l++){
            if(l>1){
                localIndex = l;
                while(true){
                    k = swapelement(k,l);
                    if(l-- == 1)
                        break;
                }
                l = localIndex;
            }else
                k = swapelement(k,l);   
        }
        return k;
    }

    private int[] swapelement(int[] ar,int in){
        int temp =0;
        if(ar[in]<ar[in-1]){
            temp = ar[in];
            ar[in]=ar[in-1];
            ar[in-1] = temp;
        }

        return ar;
    }

private int[] getDescOrder(int[] byt){
        int s =-1;
        for(int i = byt.length-1;i>=0;--i){
              int k = i-1;
              while(k >= 0){
                  if(byt[i]>byt[k]){
                      s = byt[k];
                      byt[k] = byt[i];
                      byt[i] = s;
                  }
                  k--;
              }
           }
        return byt;
    }


output:-
ascending order:- 101, 101, 102, 110, 111, 111, 112, 115


descending order:- 115, 112, 111, 111, 110, 102, 101, 101

Spring Boot Rest Controller how to return different HTTP status codes?

A nice way is to use Spring's ResponseStatusException

Rather than returning a ResponseEntityor similar you simply throw the ResponseStatusException from the controller with an HttpStatus and cause, for example:

throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "Cause description here");

or:

throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Cause description here");

This results in a response to the client containing the HTTP status (e.g. 400 Bad request) with a body like:

{
  "timestamp": "2020-07-09T04:43:04.695+0000",
  "status": 400,
  "error": "Bad Request",
  "message": "Cause description here",
  "path": "/test-api/v1/search"
}

How to crop an image using C#?

It's quite easy:

  • Create a new Bitmap object with the cropped size.
  • Use Graphics.FromImage to create a Graphics object for the new bitmap.
  • Use the DrawImage method to draw the image onto the bitmap with a negative X and Y coordinate.

How to access POST form fields

from official doc version 4

const express = require('express')
const app = express()
app.use(express.json());
app.use(express.urlencoded({ extended: true })) 

app.post('/push/send', (request, response) => {
  console.log(request.body)
})

Error:Execution failed for task ':ProjectName:mergeDebugResources'. > Crunching Cruncher *some file* failed, see logs

I was also stuck by this problem.But in my case I delete all .png images from drawable folder ,clean and rebuild application and then paste all .png images to my drawable, rebuild again. It worked fine for me.

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

Mederr's context transform works perfectly. If you need to extract orientation only use this function - you don't need any EXIF-reading libs. Below is a function for re-setting orientation in base64 image. Here's a fiddle for it. I've also prepared a fiddle with orientation extraction demo.

function resetOrientation(srcBase64, srcOrientation, callback) {
  var img = new Image();    

  img.onload = function() {
    var width = img.width,
        height = img.height,
        canvas = document.createElement('canvas'),
        ctx = canvas.getContext("2d");

    // set proper canvas dimensions before transform & export
    if (4 < srcOrientation && srcOrientation < 9) {
      canvas.width = height;
      canvas.height = width;
    } else {
      canvas.width = width;
      canvas.height = height;
    }

    // transform context before drawing image
    switch (srcOrientation) {
      case 2: ctx.transform(-1, 0, 0, 1, width, 0); break;
      case 3: ctx.transform(-1, 0, 0, -1, width, height); break;
      case 4: ctx.transform(1, 0, 0, -1, 0, height); break;
      case 5: ctx.transform(0, 1, 1, 0, 0, 0); break;
      case 6: ctx.transform(0, 1, -1, 0, height, 0); break;
      case 7: ctx.transform(0, -1, -1, 0, height, width); break;
      case 8: ctx.transform(0, -1, 1, 0, 0, width); break;
      default: break;
    }

    // draw image
    ctx.drawImage(img, 0, 0);

    // export base64
    callback(canvas.toDataURL());
  };

  img.src = srcBase64;
};

How to get last inserted row ID from WordPress database?

This is how I did it, in my code

 ...
 global $wpdb;
 $query =  "INSERT INTO... VALUES(...)" ;
 $wpdb->query(
        $wpdb->prepare($query)
);
return $wpdb->insert_id;
...

More Class Variables

Escaping backslash in string - javascript

Slightly hacky, but it works:

_x000D_
_x000D_
const input = '\text';_x000D_
const output = JSON.stringify(input).replace(/((^")|("$))/g, "").trim();_x000D_
_x000D_
console.log({ input, output });_x000D_
// { input: '\text', output: '\\text' }
_x000D_
_x000D_
_x000D_

How do you loop in a Windows batch file?

Try this code:

@echo off
color 02
set num1=0
set num2=1 
set terminator=5
:loop
set /a num1= %num1% + %num2%
if %num1%==%terminator% goto close
goto open
:close
echo %num1%
pause 
exit
:open
echo %num1%
goto loop

num1 is the number to be incremented and num2 is the value added to num1 and terminator is the value where the num1 will end. You can indicate different value for terminator in this statement (if %num1%==%terminator% goto close). This is the boolean expression goto close is the process if the boolean is true and goto open is the process if the boolean is false.

Is there a simple way to convert C++ enum to string?

Well, yet another option. A typical use case is where you need constant for the HTTP verbs as well as using is string version values.

The example:

int main () {

  VERB a = VERB::GET;
  VERB b = VERB::GET;
  VERB c = VERB::POST;
  VERB d = VERB::PUT;
  VERB e = VERB::DELETE;


  std::cout << a.toString() << std::endl;

  std::cout << a << std::endl;

  if ( a == VERB::GET ) {
    std::cout << "yes" << std::endl;
  }

  if ( a == b ) {
    std::cout << "yes" << std::endl;
  }

  if ( a != c ) {
    std::cout << "no" << std::endl;
  }

}

The VERB class:

// -----------------------------------------------------------
// -----------------------------------------------------------
class VERB {

private:

  // private constants
  enum Verb {GET_=0, POST_, PUT_, DELETE_};

  // private string values
  static const std::string theStrings[];

  // private value
  const Verb value;
  const std::string text;

  // private constructor
  VERB (Verb v) :
  value(v), text (theStrings[v])
  {
    // std::cout << " constructor \n";
  }

public:

  operator const char * ()  const { return text.c_str(); }

  operator const std::string ()  const { return text; }

  const std::string toString () const { return text; }

  bool operator == (const VERB & other) const { return (*this).value == other.value; }

  bool operator != (const VERB & other) const { return ! ( (*this) == other); }

  // ---

  static const VERB GET;
  static const VERB POST;
  static const VERB PUT;
  static const VERB DELETE;

};

const std::string VERB::theStrings[] = {"GET", "POST", "PUT", "DELETE"};

const VERB VERB::GET = VERB ( VERB::Verb::GET_ );
const VERB VERB::POST = VERB ( VERB::Verb::POST_ );
const VERB VERB::PUT = VERB ( VERB::Verb::PUT_ );
const VERB VERB::DELETE = VERB ( VERB::Verb::DELETE_ );
// end of file

inserting characters at the start and end of a string

Let's say we have a string called yourstring:

for x in range(0, [howmanytimes you want it at the beginning]):
    yourstring = "L" + yourstring
for x in range(0, [howmanytimes you want it at the end]):
    yourstring += "L"

How do you add a scroll bar to a div?

If you want to add a scroll bar using jquery the following will work. If your div had a id of 'mydiv' you could us the following jquery id selector with css property:

jQuery('#mydiv').css("overflow-y", "scroll");

Cast to generic type in C#

I had a similar problem. I have a class;

Action<T>

which has a property of type T.

How do I get the property when I don't know T? I can't cast to Action<> unless I know T.

SOLUTION:

Implement a non-generic interface;

public interface IGetGenericTypeInstance
{
    object GenericTypeInstance();
}

Now I can cast the object to IGetGenericTypeInstance and GenericTypeInstance will return the property as type object.

addClass and removeClass in jQuery - not removing class

I think that the problem is in the nesting of the elements. Once you attach an event to the outer element the clicks on the inner elements are actually firing the same click event for the outer element. So, you actually never go to the second state. What you can do is to check the clicked element. And if it is the close button then to avoid the class changing. Here is my solution:

var element = $(".clickable");
var closeButton = element.find(".close_button");
var onElementClick = function(e) {
    if(e.target !== closeButton[0]) {
        element.removeClass("spot").addClass("grown");
        element.off("click");
        closeButton.on("click", onCloseClick);
    }
}
var onCloseClick = function() {
    element.removeClass("grown").addClass("spot");
    closeButton.off("click");
    element.on("click", onElementClick);
}
element.on("click", onElementClick);

In addition I'm adding and removing event handlers.

JSFiddle -> http://jsfiddle.net/zmw9E/1/

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.

What does 'IISReset' do?

IISReset restarts the entire webserver (including all associated sites). If you're just looking to reset a single ASP.NET website, you should just recycle that AppDomain.

The most common way to reset an ASP.NET website is to edit the web.config file, but you can also create an admin page with the following:

public partial class Recycle : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        HttpRuntime.UnloadAppDomain();
    }
}

Here's a blog post I wrote with more info: Avoid IISRESET in ASP.NET Applications

How can I change the app display name build with Flutter?

One problem is that in iOS Settings (iOS 12.x) if you change the Display Name, it leaves the app name and icon in iOS Settings as the old version.

Filter dataframe rows if value in column is in a set list of values

You can use query, i.e.:

b = df.query('a > 1 & a < 5')

Get Selected Item Using Checkbox in Listview

You have to add an OnItemClickListener to the listview to determine which item was clicked, then find the checkbox.

mListView.setOnItemClickListener(new OnItemClickListener()
{
    @Override
    public void onItemClick(AdapterView<?> parent, View v, int position, long id)
    {
        CheckBox cb = (CheckBox) v.findViewById(R.id.checkbox_id);
    }
});

How to get length of a string using strlen function

For C++ strings, there's no reason to use strlen. Just use string::length:

std::cout << str.length() << std::endl;

You should strongly prefer this to strlen(str.c_str()) for the following reasons:

  1. Clarity: The length() (or size()) member functions unambiguously give back the length of the string. While it's possible to figure out what strlen(str.c_str()) does, it forces the reader to pause for a bit.

  2. Efficiency: length() and size() run in time O(1), while strlen(str.c_str()) will take Θ(n) time to find the end of the string.

  3. Style: It's good to prefer the C++ versions of functions to the C versions unless there's a specific reason to do so otherwise. This is why, for example, it's usually considered better to use std::sort over qsort or std::lower_bound over bsearch, unless some other factors come into play that would affect performance.

The only reason I could think of where strlen would be useful is if you had a C++-style string that had embedded null characters and you wanted to determine how many characters appeared before the first of them. (That's one way in which strlen differs from string::length; the former stops at a null terminator, and the latter counts all the characters in the string). But if that's the case, just use string::find:

size_t index = str.find(0);
if (index == str::npos) index = str.length();
std::cout << index << std::endl;

Hope this helps!

How to declare a variable in a PostgreSQL query

This solution is based on the one proposed by fei0x but it has the advantages that there is no need to join the value list of constants in the query and constants can be easily listed at the start of the query. It also works in recursive queries.

Basically, every constant is a single-value table declared in a WITH clause which can then be called anywhere in the remaining part of the query.

  • Basic example with two constants:
WITH
    constant_1_str AS (VALUES ('Hello World')),
    constant_2_int AS (VALUES (100))
SELECT *
FROM some_table
WHERE table_column = (table constant_1_str)
LIMIT (table constant_2_int)

Alternatively you can use SELECT * FROM constant_name instead of TABLE constant_name which might not be valid for other query languages different to postgresql.

Get google map link with latitude/longitude

I've tried doing the request you need using an iframe to show the result for latitude, longitude, and zoom needed:

<iframe 
  width="300" 
  height="170" 
  frameborder="0" 
  scrolling="no" 
  marginheight="0" 
  marginwidth="0" 
  src="https://maps.google.com/maps?q='+YOUR_LAT+','+YOUR_LON+'&hl=es&z=14&amp;output=embed"
 >
 </iframe>
 <br />
 <small>
   <a 
    href="https://maps.google.com/maps?q='+data.lat+','+data.lon+'&hl=es;z=14&amp;output=embed" 
    style="color:#0000FF;text-align:left" 
    target="_blank"
   >
     See map bigger
   </a>
 </small>

How to redirect Valgrind's output to a file?

In addition to the other answers (particularly by Lekakis), some string replacements can also be used in the option --log-file= as elaborated in the Valgrind's user manual.

Four replacements were available at the time of writing:

  • %p: Prints the current process ID
    • valgrind --log-file="myFile-%p.dat" <application-name>
  • %n: Prints file sequence number unique for the current process
    • valgrind --log-file="myFile-%p-%n.dat" <application-name>
  • %q{ENV}: Prints contents of the environment variable ENV
    • valgrind --log-file="myFile-%q{HOME}.dat" <application-name>
  • %%: Prints %
    • valgrind --log-file="myFile-%%.dat" <application-name>

How to get second-highest salary employees in a table

There are two way to do this first:

Use subquery to find the 2nd highest

SELECT MAX(salary) FROM employees
WHERE salary NOT IN (
SELECT MAX (salary) FROM employees)

But this solution is not much good as if you need to find out the 10 or 100th highest then you may be in trouble. So instead go for window function like

select * from
(
select salary,ROW_NUMBER() over( 
order by Salary desc) as
rownum from    employees
) as t where t.rownum=2

By using this method you can find out nth highest salary without any trouble.

How to find whether MySQL is installed in Red Hat?

Type mysql --version to see if it is installed.

To find location use find -name mysql.

Should I check in folder "node_modules" to Git when creating a Node.js app on Heroku?

Explicitly adding a npm version to file package.json ("npm": "1.1.x") and not checking in folder node_modules to Git worked for me.

It may be slower to deploy (since it downloads the packages each time), but I couldn't get the packages to compile when they were checked in. Heroku was looking for files that only existed on my local box.

Add URL link in CSS Background Image?

You can not add links from CSS, you will have to do so from the HTML code explicitly. For example, something like this:

<a href="whatever.html"><li id="header"></li></a>

How to publish a website made by Node.js to Github Pages?

I was able to set up github actions to automatically commit the results of a node build command (yarn build in my case but it should work with npm too) to the gh-pages branch whenever a new commit is pushed to master.

While not completely ideal as i'd like to avoid committing the built files, it seems like this is currently the only way to publish to github pages.

I based my workflow off of this guide for a different react library, and had to make the following changes to get it to work for me:

  • updated the "setup node" step to use the version found here since the one from the sample i was basing it off of was throwing errors because it could not find the correct action.
  • remove the line containing yarn export because that command does not exist and it doesn't seem to add anything helpful (you may also want to change the build line above it to suit your needs)
  • I also added an env directive to the yarn build step so that I can include the SHA hash of the commit that generated the build inside my app, but this is optional

Here is my full github action:

name: github pages

on:
    push:
        branches:
        - master

jobs:
    deploy:
        runs-on: ubuntu-18.04
        steps:
        - uses: actions/checkout@v2

        - name: Setup Node
            uses: actions/setup-node@v2-beta
            with:
            node-version: '12'

        - name: Get yarn cache
            id: yarn-cache
            run: echo "::set-output name=dir::$(yarn cache dir)"

        - name: Cache dependencies
            uses: actions/cache@v2
            with:
            path: ${{ steps.yarn-cache.outputs.dir }}
            key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
            restore-keys: |
                ${{ runner.os }}-yarn-
        - run: yarn install --frozen-lockfile
        - run: yarn build
            env:
            REACT_APP_GIT_SHA: ${{ github.SHA }}

        - name: Deploy
            uses: peaceiris/actions-gh-pages@v3
            with:
            github_token: ${{ secrets.GITHUB_TOKEN }}
            publish_dir: ./build

Alternative solution

The docs for next.js also provides instructions for setting up with Vercel which appears to be a hosting service for node.js apps similar to github pages. I have not tried this though and so cannot speak to how well it works.

Code formatting shortcuts in Android Studio for Operation Systems

The best key where you can find all commands in Eclipse is Ctrl + Shift + L.

By pressing this you can get all the commands in Eclipse.

One important is Ctrl + Shift + O to import and un-import useless imports.

PHP foreach loop key value

You can access your array keys like so:

foreach ($array as $key => $value)

@JsonProperty annotation on field as well as getter/setter

My observations based on a few tests has been that whichever name differs from the property name is one which takes effect:

For eg. consider a slight modification of your case:

@JsonProperty("fileName")
private String fileName;

@JsonProperty("fileName")
public String getFileName()
{
    return fileName;
}

@JsonProperty("fileName1")
public void setFileName(String fileName)
{
    this.fileName = fileName;
}

Both fileName field, and method getFileName, have the correct property name of fileName and setFileName has a different one fileName1, in this case Jackson will look for a fileName1 attribute in json at the point of deserialization and will create a attribute called fileName1 at the point of serialization.

Now, coming to your case, where all the three @JsonProperty differ from the default propertyname of fileName, it would just pick one of them as the attribute(FILENAME), and had any on of the three differed, it would have thrown an exception:

java.lang.IllegalStateException: Conflicting property name definitions

PDOException “could not find driver”

Had the same issue, because I forgot to go into my virtual machine. If I go to my local directory like this:

cd /www/homestead/my_project
php artisan migrate

that error will appear. But it works on my virtual machine

cd ~/homestead
vagrant ssh   
cd /www/homestead/my_project
php artisan migrate

Using multiple arguments for string formatting in Python (e.g., '%s ... %s')

For python2 you can also do this

'%(author)s in %(publication)s'%{'author':unicode(self.author),
                                  'publication':unicode(self.publication)}

which is handy if you have a lot of arguments to substitute (particularly if you are doing internationalisation)

Python2.6 onwards supports .format()

'{author} in {publication}'.format(author=self.author,
                                   publication=self.publication)

How do I determine scrollHeight?

You can also use:

$('#test').context.scrollHeight

How get permission for camera in android.(Specifically Marshmallow)

I try to add following code:

private static final int MY_CAMERA_REQUEST_CODE = 100;

@RequiresApi(api = Build.VERSION_CODES.M)

if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_REQUEST_CODE);
    }

On onCreate Function and this following code:

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == MY_CAMERA_REQUEST_CODE) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
        }
    }
}

And this worked for me :)

Android studio Gradle build speed up

This is what I did and my gradle build speed improved dramatically! from 1 min to 20sec for the first build and succeeding builds became from 40 sec to 5 sec.

In the gradle.properties file Add this:

org.gradle.jvmargs=-Xmx8192M -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8

In the Command Line Arguments via Go to File > Other Settings> default Settings >Build, Execution, Deploy> Complier and add the following arguments to Command Line Arguments

Add this:

--debug --stacktrace -a, --no-rebuild -q, --quiet --offline

See image here

Relationship between hashCode and equals method in Java

The problem you will have is with collections where unicity of elements is calculated according to both .equals() and .hashCode(), for instance keys in a HashMap.

As its name implies, it relies on hash tables, and hash buckets are a function of the object's .hashCode().

If you have two objects which are .equals(), but have different hash codes, you lose!

The part of the contract here which is important is: objects which are .equals() MUST have the same .hashCode().

This is all documented in the javadoc for Object. And Joshua Bloch says you must do it in Effective Java. Enough said.

Auto-size dynamic text to fill fixed size container

I've created a directive for AngularJS - heavely inspired by GeekyMonkey's answer but without the jQuery dependency.

Demo: http://plnkr.co/edit/8tPCZIjvO3VSApSeTtYr?p=preview

Markup

<div class="fittext" max-font-size="50" text="Your text goes here..."></div>

Directive

app.directive('fittext', function() {

  return {
    scope: {
      minFontSize: '@',
      maxFontSize: '@',
      text: '='
    },
    restrict: 'C',
    transclude: true,
    template: '<div ng-transclude class="textContainer" ng-bind="text"></div>',
    controller: function($scope, $element, $attrs) {
      var fontSize = $scope.maxFontSize || 50;
      var minFontSize = $scope.minFontSize || 8;

      // text container
      var textContainer = $element[0].querySelector('.textContainer');

      angular.element(textContainer).css('word-wrap', 'break-word');

      // max dimensions for text container
      var maxHeight = $element[0].offsetHeight;
      var maxWidth = $element[0].offsetWidth;

      var textContainerHeight;
      var textContainerWidth;      

      var resizeText = function(){
        do {
          // set new font size and determine resulting dimensions
          textContainer.style.fontSize = fontSize + 'px';
          textContainerHeight = textContainer.offsetHeight;
          textContainerWidth = textContainer.offsetWidth;

          // shrink font size
          var ratioHeight = Math.floor(textContainerHeight / maxHeight);
          var ratioWidth = Math.floor(textContainerWidth / maxWidth);
          var shrinkFactor = ratioHeight > ratioWidth ? ratioHeight : ratioWidth;
          fontSize -= shrinkFactor;

        } while ((textContainerHeight > maxHeight || textContainerWidth > maxWidth) && fontSize > minFontSize);        
      };

      // watch for changes to text
      $scope.$watch('text', function(newText, oldText){
        if(newText === undefined) return;

        // text was deleted
        if(oldText !== undefined && newText.length < oldText.length){
          fontSize = $scope.maxFontSize;
        }
        resizeText();
      });
    }
  };
});

Effect of NOLOCK hint in SELECT statements

It will be faster because it doesnt have to wait for locks

What does '--set-upstream' do?

git branch --set-upstream <remote-branch>

sets the default remote branch for the current local branch.

Any future git pull command (with the current local branch checked-out),
will attempt to bring in commits from the <remote-branch> into the current local branch.


One way to avoid having to explicitly type --set-upstream is to use its shorthand flag -u as follows:

git push -u origin local-branch

This sets the upstream association for any future push/pull attempts automatically.
For more details, checkout this detailed explanation about upstream branches and tracking.


To avoid confusion, recent versions of git deprecate this somewhat ambiguous --set-upstream option in favour of a more verbose --set-upstream-to option with identical syntax and behaviour

git branch --set-upstream-to <origin/remote-branch>

Magento: get a static block as html in a phtml file

This should work as tested.

<?php
$filter = new Mage_Widget_Model_Template_Filter();
$_widget = $filter->filter('{{widget type="cms/widget_page_link" template="cms/widget/link/link_block.phtml" page_id="2"}}');
echo $_widget;
?>

Amazon products API - Looking for basic overview and information

Straight from the horse's moutyh: Summary of Product Advertising API Operations which has the following categories:

  • Find Items
  • Find Out More About Specific Items
  • Shopping Cart
  • Customer Content
  • Seller Information
  • Other Operations

How do you change video src using jQuery?

This is working on Flowplayer 6.0.2.

<script>
    flowplayer().load({
         sources: [
            { type: "video/mp4",  src: variable }
            ]
        });
</script>

where variable is a javascript/jquery variable value, The video tag should be something this

<div class="flowplayer">
   <video>
      <source type="video/mp4" src="" class="videomp4">
   </video>
</div>

Hope it helps anyone.

Does Internet Explorer 8 support HTML 5?

According to http://msdn.microsoft.com/en-us/library/cc288472(VS.85).aspx#html, IE8 will have "strong" HTML 5 support. I haven't seen anything discussing exactly what "strong support" entails, but I can say that yes, some HTML5 stuff is going to make it into IE8.

Is it better to return null or empty collection?

Depends on the situation. If it is a special case, then return null. If the function just happens to return an empty collection, then obviously returning that is ok. However, returning an empty collection as a special case because of invalid parameters or other reasons is NOT a good idea, because it is masking a special case condition.

Actually, in this case I usually prefer to throw an exception to make sure it is REALLY not ignored :)

Saying that it makes the code more robust (by returning an empty collection) as they do not have to handle the null condition is bad, as it is simply masking a problem that should be handled by the calling code.

How to reload the current route with the angular 2 router

There are different approaches to refresh the current route

Change router behaviour (Since Angular 5.1) Set the routers onSameUrlNavigation to 'reload'. This will emit the router events on same URL Navigation.

  • You can then handle them by subscribing to a route
  • You can use it with the combination of runGuardsAndResolvers to rerun resolvers

Leave the router untouched

  • Pass a refresh queryParam with the current timestamp in the URL and subscribe to queryParams in your routed component.
  • Use the activate Event of the router-outlet to get a hold of the routed component.

I have written a more detailed explanation under https://medium.com/@kevinkreuzer/refresh-current-route-in-angular-512a19d58f6e

Hope this helps.

Extracting first n columns of a numpy matrix

I know this is quite an old question -

A = [[1, 2, 3],
     [4, 5, 6],
     [7, 8, 9]]

Let's say, you want to extract the first 2 rows and first 3 columns

A_NEW = A[0:2, 0:3]
A_NEW = [[1, 2, 3],
         [4, 5, 6]]

Understanding the syntax

A_NEW = A[start_index_row : stop_index_row, 
          start_index_column : stop_index_column)]

If one wants row 2 and column 2 and 3

A_NEW = A[1:2, 1:3]

Reference the numpy indexing and slicing article - Indexing & Slicing

ImportError: No module named PyQt4.QtCore

I had the same issue when uninstalled my Python27 and re-installed it.

I downloaded the sip-4.15.5 and PyQt-win-gpl-4.10.4 and installed/configured both of them. it still gives 'ImportError: No module named PyQt4.QtCore'. I tried to move the files/folders in Lib to make it looked 'have' but not working.

in fact, jut download the Windows 64 bit installer for a suitable Python version (my case) from http://www.riverbankcomputing.co.uk/software/pyqt/download and installed it, will do the job.

* March 2017 update *

The given link says, Binary installers for Windows are no longer provided.

See cgohlke's answer at, PyQt4 and 64-bit python.

  1. Download the .whl file at http://www.lfd.uci.edu/~gohlke/pythonlibs/#pyqt4.
  2. Use pip to install the downloaded .whl file.

best way to get folder and file list in Javascript

Why to invent the wheel?

There is a very popular NPM package, that let you do things like that easy.

var recursive = require("recursive-readdir");

recursive("some/path", function (err, files) {
  // `files` is an array of file paths
  console.log(files);
});

Lear more:

A fatal error occurred while creating a TLS client credential. The internal error state is 10013

I found this here: https://port135.com/schannel-the-internal-error-state-is-10013-solved/

"Correct file permissions Correct the permissions on the c:\ProgramData\Microsoft\Crypto\RSA\MachineKeys folder:

Everyone Access: Special Applies to 'This folder only' Network Service Access: Read & Execute Applies to 'This folder, subfolders and files' Administrators Access: Full Control Applies to 'This folder, subfolder and files' System Access: Full control Applies to 'This folder, subfolder and Files' IUSR Access: Full Control Applies to 'This folder, subfolder and files' The internal error state is 10013 After these changes, restart the server. The 10013 errors should disappear."

How to filter files when using scp to copy dir recursively?

Below command for files.

scp `find . -maxdepth 1 -name "*.log" \! -name "hs_err_pid2801.log" -type f` root@IP:/tmp/test/

  1. IP will be destination server IP address.
  2. -name "*.log" for include files.
  3. \! -name "hs_err_pid2801.log" for exclude files.
  4. . is current working dir.
  5. -type f for file type.

Below command for directory.

scp -r `find . -maxdepth 1 -name "lo*" \! -name "localhost" -type d` root@IP:/tmp/test/

you can customize above command as per your requirement.

MySQLi prepared statements error reporting

Each method of mysqli can fail. You should test each return value. If one fails, think about whether it makes sense to continue with an object that is not in the state you expect it to be. (Potentially not in a "safe" state, but I think that's not an issue here.)

Since only the error message for the last operation is stored per connection/statement you might lose information about what caused the error if you continue after something went wrong. You might want to use that information to let the script decide whether to try again (only a temporary issue), change something or to bail out completely (and report a bug). And it makes debugging a lot easier.

$stmt = $mysqli->prepare("INSERT INTO testtable VALUES (?,?,?)");
// prepare() can fail because of syntax errors, missing privileges, ....
if ( false===$stmt ) {
  // and since all the following operations need a valid/ready statement object
  // it doesn't make sense to go on
  // you might want to use a more sophisticated mechanism than die()
  // but's it's only an example
  die('prepare() failed: ' . htmlspecialchars($mysqli->error));
}

$rc = $stmt->bind_param('iii', $x, $y, $z);
// bind_param() can fail because the number of parameter doesn't match the placeholders in the statement
// or there's a type conflict(?), or ....
if ( false===$rc ) {
  // again execute() is useless if you can't bind the parameters. Bail out somehow.
  die('bind_param() failed: ' . htmlspecialchars($stmt->error));
}

$rc = $stmt->execute();
// execute() can fail for various reasons. And may it be as stupid as someone tripping over the network cable
// 2006 "server gone away" is always an option
if ( false===$rc ) {
  die('execute() failed: ' . htmlspecialchars($stmt->error));
}

$stmt->close();

Just a few notes six years later...

The mysqli extension is perfectly capable of reporting operations that result in an (mysqli) error code other than 0 via exceptions, see mysqli_driver::$report_mode.
die() is really, really crude and I wouldn't use it even for examples like this one anymore.
So please, only take away the fact that each and every (mysql) operation can fail for a number of reasons; even if the exact same thing went well a thousand times before....

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

You can use "translateX"

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

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

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

Difference between npx and npm?

Here's an example of NPX in action: npx cowsay hello

If you type that into your bash terminal you'll see the result. The benefit of this is that npx has temporarily installed cowsay. There is no package pollution since cowsay is not permanently installed. This is great for one off packages where you want to avoid package pollution.

As mentioned in other answers, npx is also very useful in cases where (with npm) the package needs to be installed then configured before running. E.g. instead of using npm to install and then configure the json.package file and then call the configured run command just use npx instead. A real example: npx create-react-app my-app

Sending message through WhatsApp

This works to me:

public static void shareWhatsApp(Activity appActivity, String texto) {

    Intent sendIntent = new Intent(Intent.ACTION_SEND);     
    sendIntent.setType("text/plain");
    sendIntent.putExtra(android.content.Intent.EXTRA_TEXT, texto);

    PackageManager pm = appActivity.getApplicationContext().getPackageManager();
    final List<ResolveInfo> matches = pm.queryIntentActivities(sendIntent, 0);
    boolean temWhatsApp = false;
    for (final ResolveInfo info : matches) {
      if (info.activityInfo.packageName.startsWith("com.whatsapp"))  {
          final ComponentName name = new ComponentName(info.activityInfo.applicationInfo.packageName, info.activityInfo.name);
          sendIntent.addCategory(Intent.CATEGORY_LAUNCHER);
          sendIntent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY | Intent.FLAG_ACTIVITY_NEW_TASK);
          sendIntent.setComponent(name);
          temWhatsApp = true;
          break;
      }
    }               

    if(temWhatsApp) {
        //abre whatsapp
        appActivity.startActivity(sendIntent);
    } else {
        //alerta - você deve ter o whatsapp instalado
        Toast.makeText(appActivity, appActivity.getString(R.string.share_whatsapp), Toast.LENGTH_SHORT).show();
    }
}

When is JavaScript synchronous?

JavaScript is always synchronous and single-threaded. If you're executing a JavaScript block of code on a page then no other JavaScript on that page will currently be executed.

JavaScript is only asynchronous in the sense that it can make, for example, Ajax calls. The Ajax call will stop executing and other code will be able to execute until the call returns (successfully or otherwise), at which point the callback will run synchronously. No other code will be running at this point. It won't interrupt any other code that's currently running.

JavaScript timers operate with this same kind of callback.

Describing JavaScript as asynchronous is perhaps misleading. It's more accurate to say that JavaScript is synchronous and single-threaded with various callback mechanisms.

jQuery has an option on Ajax calls to make them synchronously (with the async: false option). Beginners might be tempted to use this incorrectly because it allows a more traditional programming model that one might be more used to. The reason it's problematic is that this option will block all JavaScript on the page until it finishes, including all event handlers and timers.

Smooth scrolling when clicking an anchor link

There are already a lot of good answers here - however they are all missing the fact that empty anchors have to be excluded. Otherwise those scripts generate JavaScript errors as soon as an empty anchor is clicked.

In my opinion the correct answer is like this:

$('a[href*=\\#]:not([href$=\\#])').click(function() {
    event.preventDefault();

    $('html, body').animate({
        scrollTop: $($.attr(this, 'href')).offset().top
    }, 500);
});

How to count the occurrence of certain item in an ndarray?

Personally, I'd go for: (y == 0).sum() and (y == 1).sum()

E.g.

import numpy as np
y = np.array([0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1])
num_zeros = (y == 0).sum()
num_ones = (y == 1).sum()

How do I update Anaconda?

Open Anaconda cmd in base mode:

Then use conda update conda to update Anaconda.

You can then use conda update --all to update all the requirements for Anaconda:

conda update conda
conda update --all

Could not connect to Redis at 127.0.0.1:6379: Connection refused with homebrew

In my case, it was the password that contained some characters like ', after changing it the server started without problems.

Creating .pem file for APNS?

NOTE: You must have the Team Agent or Admin role in App Store Connect to perform any of these tasks. If you are not part of a Team in App Store Connect this probably does not affect you.

Sending push notifications to an iOS application requires creating encyption keys. In the past this was a cumbersome process that used SSL keys and certificates. Each SSL certificate was specific to a single iOS application. In 2016 Apple introduced a new authentication key mechanism that is more reliable and easier to use. The new authentication keys are more flexible, simple to maintain and apply to more than on iOS app.

Even though it has been years since authentication keys were introduced not every service supports them. FireBase and Amazon Pinpoint support authentication keys. Amazon SNS, Urban Airship, Twilio, and LeanPlum do not. Many open source software packages do not yet support authentication keys.

To create the required SSL certificate and export it as PEM file containing public and private keys:

  1. Navigate to Certificates, Identifiers & Profiles
  2. Create or Edit Your App ID.
  3. Enable Push Notifications for the App ID
  4. Add an SSL Certificate to the App ID
  5. Convert the certificate to PEM format

If you already have the SSL certificate set up for the app in the Apple Developer Center website you can skip ahead to Convert the certificate to PEM format. Keep in mind that you will run into problems if you do not also have the private key that was generated on the Mac that created the signing request that was uploaded to Apple.

Read on to see how to avoid losing track of that private key.

Navigate to Certificates, Identifiers & Profiles

Xcode does not control certificates or keys for push notifications. To create keys and enable push notifications for an app you must go to the Apple Developer Center website. The Certificates, Identifiers & Profiles section of your account controls App IDs and certificates.

To access certificates and profiles you must either have a paid Apple Developer Program membership or be part of a Team that does.

  1. Log into the Apple Developer website enter image description here
  2. Go to Account, then Certificates, Identifiers & Profiles enter image description here

Create an App ID

Apps that use push notifications can not use wildcard App IDs or provisioning profiles. Each app requires you to set up an App ID record in the Apple Developer Center portal to enable push notifications.

  1. Go to App IDs under Identifiers
  2. Search for your app using the bundle identifier. It may already exist.
  3. If there is no existing App ID for the app click the (+) button to create it.
  4. Select Explicit App ID in the App ID Suffix section. enter image description here
  5. Enter the bundle identifier for the app.
  6. Scroll to the bottom and enable Push Notifications. enter image description here
  7. Click Continue.
  8. On the next screen click Register to complete creating the App ID. enter image description here

Enable Push Notifications for the App ID

  1. Go to App IDs under Identifiers
  2. Click on the App ID to see details and scroll to the bottom. enter image description here
  3. Click Edit enter image description here
  4. In the App ID Settings screen scroll down to Push Notifications enter image description here
  5. Select the checkbox to enable push notifications. enter image description here

Creating SSL certificates for push notifications is a process of several tasks. Each task has several steps. All of these are necessary to export the keys in P12 or PEM format. Review the steps before proceeding.

Add an SSL Certificate to the App ID

  1. Under Development SSL Certificate click Create Certificate. You will need to do this later for production as well.
  2. Apple will ask you to create a Certificate Signing Request enter image description here

To create a certificate you will need to make a Certificate Signing Request (CSR) on a Mac and upload it to Apple.

Later if you need to export this certificate as a pkcs12 (aka p12) file you will need to use the keychain from the same Mac. When the signing request is created Keychain Access generates a set of keys in the default keychain. These keys are necessary for working with the certificate Apple will create from the signing request.

It is a good practice to have a separate keychain specifically for credentials used for development. If you do this make sure this keychain is set to be the default before using Certificate Assistant.

Create a Keychain for Development Credentials

  1. Open Keychain Access on your Mac
  2. In the File menu select New Keychain...
  3. Give your keychain a descriptive name, like "Shared Development" or the name of your application

Create a Certificate Signing Request (CSR)

When creating the Certificate Signing Request the Certificate Assistant generates two encryption keys in the default keychain. It is important to make the development keychain the default so the keys are in the right keychain.

  1. Open Keychain Access on your Mac.
  2. Control-click on the development keychain in the list of keychains
  3. Select Make keychain "Shared Development" Default enter image description here
  4. From the Keychain Access menu select Certificate Assistant, then Request a Certificate From a Certificate Authority... from the sub menu. enter image description here
  5. When the Certificate Assistant appears check Saved To Disk. enter image description here
  6. Enter the email address associated with your Apple Developer Program membership in the User Email Address field.
  7. Enter a name for the key in the Common Name field. It is a good idea to use the bundle ID of the app as part of the common name. This makes it easy to tell what certificates and keys belong to which app.
  8. Click continue. Certificate Assistant will prompt to save the signing request to a file.
  9. In Keychain Access make the "login" keychain the default again.

Creating the signing request generated a pair of keys. Before the signing request is uploaded verify that the development keychain has the keys. Their names will be the same as the Common Name used in the signing request.

enter image description here

Upload the Certificate Signing Request (CSR)

Once the Certicate Signing Request is created upload it to the Apple Developer Center. Apple will create the push notification certificate from the signing request.

  1. Upload the Certificate Signing Request
  2. Download the certificate Apple has created from the Certificate Signing Request enter image description here
  3. In Keychain Access select the development keychain from the list of keychains
  4. From the File menu select Import Items... enter image description here
  5. Import the certificate file downloaded from Apple

Your development keychain should now show the push certificate with a private key under My Certificates in Keychain Access:

enter image description here

At this point the development keychain should be backed up. Many teams keep their push certificates on secure USB drives, commit to internal version control or use a backup solution like Time Machine. The development keychain can be shared between different team members because it does not contain any personal code signing credentials.

Keychain files are located in ~/Library/Keychains.

Some third party push services require certificates in Privacy Enhanced Mail (PEM) format, while others require Public-Key Cryptography Standards #12 (PKCS12 or P12). The certificate downloaded from Apple can be used to export certificates in these formats - but only if you have kept the private key.

Convert the certificate to PEM format

  1. In Keychain Access select the development keychain created earlier.
  2. Select the push certificate in My Certificates. There should be a private key with it. ![Download CER push certificate](keychain/import complete.png)
  3. From the File menu select Export Items... enter image description here
  4. In the save panel that opens, select Privacy Enhanced Mail (.pem) as the file format.
  5. Save the file

How do I enable NuGet Package Restore in Visual Studio?

VS 2019 Version 16.4.4 Solution targeting .NET Core 3.1

After having tried almost all the solutions proposed here, I closed VS. When I reopened it, after some seconds all was back to be OK...

Angular-Material DateTime Picker Component?

Angular Material 10 now includes a new date range picker.

To use the new date range picker, you can use the mat-date-range-input and mat-date-range-picker components.

Example

HTML

<mat-form-field>
  <mat-label>Enter a date range</mat-label>
  <mat-date-range-input [rangePicker]="picker">
    <input matStartDate matInput placeholder="Start date">
    <input matEndDate matInput placeholder="End date">
  </mat-date-range-input>
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-date-range-picker #picker></mat-date-range-picker>
</mat-form-field>

You can read and learn more about this in their official documentation.

Unfortunately, they still haven't build a timepicker on this release.

Open File in Another Directory (Python)

If you know the full path to the file you can just do something similar to this. However if you question directly relates to relative paths, that I am unfamiliar with and would have to research and test.

path = 'C:\\Users\\Username\\Path\\To\\File'

with open(path, 'w') as f:
    f.write(data)

Edit:

Here is a way to do it relatively instead of absolute. Not sure if this works on windows, you will have to test it.

import os

cur_path = os.path.dirname(__file__)

new_path = os.path.relpath('..\\subfldr1\\testfile.txt', cur_path)
with open(new_path, 'w') as f:
    f.write(data)

Edit 2: One quick note about __file__, this will not work in the interactive interpreter due it being ran interactively and not from an actual file.

Is JavaScript's "new" keyword considered harmful?

Crockford has done a lot to popularize good JavaScript techniques. His opinionated stance on key elements of the language have sparked many useful discussions. That said, there are far too many people that take each proclamation of "bad" or "harmful" as gospel, refusing to look beyond one man's opinion. It can be a bit frustrating at times.

Use of the functionality provided by the new keyword has several advantages over building each object from scratch:

  1. Prototype inheritance. While often looked at with a mix of suspicion and derision by those accustomed to class-based OO languages, JavaScript's native inheritance technique is a simple and surprisingly effective means of code re-use. And the new keyword is the canonical (and only available cross-platform) means of using it.
  2. Performance. This is a side-effect of #1: if I want to add 10 methods to every object I create, I could just write a creation function that manually assigns each method to each new object... Or, I could assign them to the creation function's prototype and use new to stamp out new objects. Not only is this faster (no code needed for each and every method on the prototype), it avoids ballooning each object with separate properties for each method. On slower machines (or especially, slower JS interpreters) when many objects are being created this can mean a significant savings in time and memory.

And yes, new has one crucial disadvantage, ably described by other answers: if you forget to use it, your code will break without warning. Fortunately, that disadvantage is easily mitigated - simply add a bit of code to the function itself:

function foo()
{
   // if user accidentally omits the new keyword, this will 
   // silently correct the problem...
   if ( !(this instanceof foo) )
      return new foo();

   // constructor logic follows...
}

Now you can have the advantages of new without having to worry about problems caused by accidentally misuse. You could even add an assertion to the check if the thought of broken code silently working bothers you. Or, as some commented, use the check to introduce a runtime exception:

if ( !(this instanceof arguments.callee) ) 
   throw new Error("Constructor called as a function");

(Note that this snippet is able to avoid hard-coding the constructor function name, as unlike the previous example it has no need to actually instantiate the object - therefore, it can be copied into each target function without modification.)

John Resig goes into detail on this technique in his Simple "Class" Instantiation post, as well as including a means of building this behavior into your "classes" by default. Definitely worth a read... as is his upcoming book, Secrets of the JavaScript Ninja, which finds hidden gold in this and many other "harmful" features of the JavaScript language (the chapter on with is especially enlightening for those of us who initially dismissed this much-maligned feature as a gimmick).

Add to Array jQuery

push is a native javascript method. You could use it like this:

var array = [1, 2, 3];
array.push(4); // array now is [1, 2, 3, 4]
array.push(5, 6, 7); // array now is [1, 2, 3, 4, 5, 6, 7]

applying css to specific li class

You have specified different colors for the li elements but it is being overridden by the specified color in the a within the li. Remove color: #C1C1C1; style from a element and it should work.

Why would one mark local variables and method parameters as "final" in Java?

Yes do it.

It's about readability. It's easier to reason about the possible states of the program when you know that variables are assigned once and only once.

A decent alternative is to turn on the IDE warning when a parameter is assigned, or when a variable (other than a loop variable) is assigned more than once.

Online SQL Query Syntax Checker

SQLFiddle will let you test out your queries, while it doesn't explicitly correct syntax etc. per se it does let you play around with the script and will definitely let you know if things are working or not.

How to compare two double values in Java?

You can use Double.compare; It compares the two specified double values.

Which is the best library for XML parsing in java

Java supports two methods for XML parsing out of the box.

SAXParser

You can use this parser if you want to parse large XML files and/or don't want to use a lot of memory.

http://download.oracle.com/javase/6/docs/api/javax/xml/parsers/SAXParserFactory.html

Example: http://www.mkyong.com/java/how-to-read-xml-file-in-java-sax-parser/

DOMParser

You can use this parser if you need to do XPath queries or need to have the complete DOM available.

http://download.oracle.com/javase/6/docs/api/javax/xml/parsers/DocumentBuilderFactory.html

Example: http://www.mkyong.com/java/how-to-read-xml-file-in-java-dom-parser/

Range with step of type float

Here is a special case that might be good enough:

 [ (1.0/divStep)*x for x in range(start*divStep, stop*divStep)]

In your case this would be:

#for(float x = 0; x < 10; x += 0.5f) { /* ... */ } ==>
start = 0
stop  = 10
divstep = 1/.5 = 2 #This needs to be int, thats why I said 'special case'

and so:

>>> [ .5*x for x in range(0*2, 10*2)]
[0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5]

How do I parse a string to a float or int?

The YAML parser can help you figure out what datatype your string is. Use yaml.load(), and then you can use type(result) to test for type:

>>> import yaml

>>> a = "545.2222"
>>> result = yaml.load(a)
>>> result
545.22220000000004
>>> type(result)
<type 'float'>

>>> b = "31"
>>> result = yaml.load(b)
>>> result
31
>>> type(result)
<type 'int'>

>>> c = "HI"
>>> result = yaml.load(c)
>>> result
'HI'
>>> type(result)
<type 'str'>

Android ListView Divider

This is a workaround, but works for me:

Created res/drawable/divider.xml as follows:

<?xml version="1.0" encoding="UTF-8"?>
<shape
  xmlns:android="http://schemas.android.com/apk/res/android">
    <gradient android:startColor="#ffcdcdcd" android:endColor="#ffcdcdcd" android:angle="270.0" />
</shape>

And in styles.xml for listview item, I added the following lines:

    <item name="android:divider">@drawable/divider</item>
    <item name="android:dividerHeight">1px</item>

Crucial part was to include this 1px setting. Of course, drawable uses gradient (with 1px) and that's not the optimal solution. I tried using stroke but didn't get it to work. (You don't seem to use styles, so just add android:dividerHeight="1px" attribute for the ListView.

How to find third or n?? maximum salary from salary table?

Method 1:

SELECT TOP 1 salary FROM (
SELECT TOP 3 salary 
 FROM employees 
  ORDER BY salary DESC) AS emp 
 ORDER BY salary ASC

Method 2:

  Select EmpName,salary from
  (
    select EmpName,salary ,Row_Number() over(order by salary desc) as rowid      
     from EmpTbl)
   as a where rowid=3

How to use the curl command in PowerShell?

Use splatting.

$CurlArgument = '-u', '[email protected]:yyyy',
                '-X', 'POST',
                'https://xxx.bitbucket.org/1.0/repositories/abcd/efg/pull-requests/2229/comments',
                '--data', 'content=success'
$CURLEXE = 'C:\Program Files\Git\mingw64\bin\curl.exe'
& $CURLEXE @CurlArgument

Display image at 50% of its "native" size

Maybe one of the easiest solutions would be to use the x descriptor of the srcset attribute as such:

_x000D_
_x000D_
<!-- Original image -->
<img src="https://fr.wikipedia.org/static/images/mobile/copyright/wikipedia.png" />

<!-- With a 80% size reduction (1/0.8=1.25) -->
<img srcset="https://fr.wikipedia.org/static/images/mobile/copyright/wikipedia.png 1.25x" />

<!-- With a 50% size reduction (1/0.5=2) -->
<img srcset="https://fr.wikipedia.org/static/images/mobile/copyright/wikipedia.png 2x" />
_x000D_
_x000D_
_x000D_

Currently supported by all browsers except IE. (caniuse)

MDN documentation

Get connection string from App.config

Can't you just do the following:

var connection = 
    System.Configuration.ConfigurationManager.
    ConnectionStrings["Test"].ConnectionString;

Your assembly also needs a reference to System.Configuration.dll

Why am I getting ImportError: No module named pip ' right after installing pip?

The ensurepip module was added in version 3.4 and then backported to 2.7.9.

So make sure your Python version is at least 2.7.9 if using Python 2, and at least 3.4 if using Python 3.

Is there a Java equivalent or methodology for the typedef keyword in C++?

Really, the only use of typedef that carries over to Javaland is aliasing- that is, giving the same class multiple names. That is, you've got a class "A" and you want "B" to refer to the same thing. In C++, you'd be doing "typedef B A;"

Unfortunately, they just don't support it. However, if you control all the types involved you CAN pull a nasty hack at the library level- you either extend B from A or have B implement A.

Compare two dates with JavaScript

var date = new Date(); // will give you todays date.

// following calls, will let you set new dates.
setDate()   
setFullYear()   
setHours()  
setMilliseconds()   
setMinutes()    
setMonth()  
setSeconds()    
setTime()

var yesterday = new Date();
yesterday.setDate(...date info here);

if(date>yesterday)  // will compare dates

Circular dependency in Spring

It just does it. It instantiates a and b, and injects each one into the other (using their setter methods).

What's the problem?

How to download fetch response in react as file

Browser technology currently doesn't support downloading a file directly from an Ajax request. The work around is to add a hidden form and submit it behind the scenes to get the browser to trigger the Save dialog.

I'm running a standard Flux implementation so I'm not sure what the exact Redux (Reducer) code should be, but the workflow I just created for a file download goes like this...

  1. I have a React component called FileDownload. All this component does is render a hidden form and then, inside componentDidMount, immediately submit the form and call it's onDownloadComplete prop.
  2. I have another React component, we'll call it Widget, with a download button/icon (many actually... one for each item in a table). Widget has corresponding action and store files. Widget imports FileDownload.
  3. Widget has two methods related to the download: handleDownload and handleDownloadComplete.
  4. Widget store has a property called downloadPath. It's set to null by default. When it's value is set to null, there is no file download in progress and the Widget component does not render the FileDownload component.
  5. Clicking the button/icon in Widget calls the handleDownload method which triggers a downloadFile action. The downloadFile action does NOT make an Ajax request. It dispatches a DOWNLOAD_FILE event to the store sending along with it the downloadPath for the file to download. The store saves the downloadPath and emits a change event.
  6. Since there is now a downloadPath, Widget will render FileDownload passing in the necessary props including downloadPath as well as the handleDownloadComplete method as the value for onDownloadComplete.
  7. When FileDownload is rendered and the form is submitted with method="GET" (POST should work too) and action={downloadPath}, the server response will now trigger the browser's Save dialog for the target download file (tested in IE 9/10, latest Firefox and Chrome).
  8. Immediately following the form submit, onDownloadComplete/handleDownloadComplete is called. This triggers another action that dispatches a DOWNLOAD_FILE event. However, this time downloadPath is set to null. The store saves the downloadPath as null and emits a change event.
  9. Since there is no longer a downloadPath the FileDownload component is not rendered in Widget and the world is a happy place.

Widget.js - partial code only

import FileDownload from './FileDownload';

export default class Widget extends Component {
    constructor(props) {
        super(props);
        this.state = widgetStore.getState().toJS();
    }

    handleDownload(data) {
        widgetActions.downloadFile(data);
    }

    handleDownloadComplete() {
        widgetActions.downloadFile();
    }

    render() {
        const downloadPath = this.state.downloadPath;

        return (

            // button/icon with click bound to this.handleDownload goes here

            {downloadPath &&
                <FileDownload
                    actionPath={downloadPath}
                    onDownloadComplete={this.handleDownloadComplete}
                />
            }
        );
    }

widgetActions.js - partial code only

export function downloadFile(data) {
    let downloadPath = null;

    if (data) {
        downloadPath = `${apiResource}/${data.fileName}`;
    }

    appDispatcher.dispatch({
        actionType: actionTypes.DOWNLOAD_FILE,
        downloadPath
    });
}

widgetStore.js - partial code only

let store = Map({
    downloadPath: null,
    isLoading: false,
    // other store properties
});

class WidgetStore extends Store {
    constructor() {
        super();
        this.dispatchToken = appDispatcher.register(action => {
            switch (action.actionType) {
                case actionTypes.DOWNLOAD_FILE:
                    store = store.merge({
                        downloadPath: action.downloadPath,
                        isLoading: !!action.downloadPath
                    });
                    this.emitChange();
                    break;

FileDownload.js
- complete, fully functional code ready for copy and paste
- React 0.14.7 with Babel 6.x ["es2015", "react", "stage-0"]
- form needs to be display: none which is what the "hidden" className is for

import React, {Component, PropTypes} from 'react';
import ReactDOM from 'react-dom';

function getFormInputs() {
    const {queryParams} = this.props;

    if (queryParams === undefined) {
        return null;
    }

    return Object.keys(queryParams).map((name, index) => {
        return (
            <input
                key={index}
                name={name}
                type="hidden"
                value={queryParams[name]}
            />
        );
    });
}

export default class FileDownload extends Component {

    static propTypes = {
        actionPath: PropTypes.string.isRequired,
        method: PropTypes.string,
        onDownloadComplete: PropTypes.func.isRequired,
        queryParams: PropTypes.object
    };

    static defaultProps = {
        method: 'GET'
    };

    componentDidMount() {
        ReactDOM.findDOMNode(this).submit();
        this.props.onDownloadComplete();
    }

    render() {
        const {actionPath, method} = this.props;

        return (
            <form
                action={actionPath}
                className="hidden"
                method={method}
            >
                {getFormInputs.call(this)}
            </form>
        );
    }
}

Support for the experimental syntax 'classProperties' isn't currently enabled

For ejected create-react-app projects

I just solved my case adding the following lines to my webpack.config.js:

  presets: [
    [
      require.resolve('babel-preset-react-app/dependencies'),
      { helpers: true },
    ],
    /* INSERT START */
    require.resolve('@babel/preset-env'),
    require.resolve('@babel/preset-react'),
      {
      'plugins': ['@babel/plugin-proposal-class-properties']
    } 
    /* INSERTED END */
  ],

How to prevent the "Confirm Form Resubmission" dialog?

I was having this problem and added this JavaScript to the bottom of my page (read it at https://www.webtrickshome.com/faq/how-to-stop-form-resubmission-on-page-refresh) and it seemed to work. It seems much simpler a solution. Any drawbacks?

<script>
if ( window.history.replaceState ) {
  window.history.replaceState( null, null, window.location.href );
}
</script>

Thanks,

doug

curl: (60) SSL certificate problem: unable to get local issuer certificate

It is failing as cURL is unable to verify the certificate provided by the server.

There are two options to get this to work:

  1. Use cURL with -k option which allows curl to make insecure connections, that is cURL does not verify the certificate.

  2. Add the root CA (the CA signing the server certificate) to /etc/ssl/certs/ca-certificates.crt

You should use option 2 as it's the option that ensures that you are connecting to secure FTP server.

Compare dates in MySQL

this is what it worked for me:

select * from table
where column
BETWEEN STR_TO_DATE('29/01/15', '%d/%m/%Y')
 AND STR_TO_DATE('07/10/15', '%d/%m/%Y')

Please, note that I had to change STR_TO_DATE(column, '%d/%m/%Y') from previous solutions, as it was taking ages to load

How to parse a CSV in a Bash script?

For situations where the data does not contain any special characters, the solution suggested by Nate Kohl and ghostdog74 is good.

If the data contains commas or newlines inside the fields, awk may not properly count the field numbers and you'll get incorrect results.

You can still use awk, with some help from a program I wrote called csvquote (available at https://github.com/dbro/csvquote):

csvquote inputfile.csv | awk -F, -v index=$INDEX -v value=$VALUE '$index == value {print}' | csvquote -u

This program finds special characters inside quoted fields, and temporarily replaces them with nonprinting characters which won't confuse awk. Then they get restored after awk is done.

Array of strings in groovy

If you really want to create an array rather than a list use either

String[] names = ["lucas", "Fred", "Mary"]

or

def names = ["lucas", "Fred", "Mary"].toArray()

Expression must be a modifiable lvalue

The assignment operator has lower precedence than &&, so your condition is equivalent to:

if ((match == 0 && k) = m)

But the left-hand side of this is an rvalue, namely the boolean resulting from the evaluation of the sub­expression match == 0 && k, so you cannot assign to it.

By contrast, comparison has higher precedence, so match == 0 && k == m is equivalent to:

if ((match == 0) && (k == m))

How to query SOLR for empty fields?

One caveat! If you want to compose this via OR or AND you cannot use it in this form:

-myfield:*

but you must use

(*:* NOT myfield:*)

This form is perfectly composable. Apparently SOLR will expand the first form to the second, but only when it is a top node. Hope this saves you some time!

jQuery - Uncaught RangeError: Maximum call stack size exceeded

Your calls are made recursively which pushes functions on to the stack infinitely that causes max call stack exceeded error due to recursive behavior. Instead try using setTimeout which is a callback.

Also based on your markup your selector is wrong. it should be #advisersDiv

Demo

function fadeIn() {
    $('#pulseDiv').find('div#advisersDiv').delay(400).addClass("pulse");
    setTimeout(fadeOut,1); //<-- Provide any delay here
};

function fadeOut() {
    $('#pulseDiv').find('div#advisersDiv').delay(400).removeClass("pulse");
    setTimeout(fadeIn,1);//<-- Provide any delay here
};
fadeIn();

How to undo 'git reset'?

Old question, and the posted answers work great. I'll chime in with another option though.

git reset ORIG_HEAD

ORIG_HEAD references the commit that HEAD previously referenced.

socket.error: [Errno 48] Address already in use

I am new to Python, but after my brief research I found out that this is typical of sockets being binded. It just so happens that the socket is still being used and you may have to wait to use it. Or, you can just add:

tcpSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

This should make the port available within a shorter time. In my case, it made the port available almost immediately.

How can I count the number of children?

You can do this using jQuery:

This method gets a list of its children then counts the length of that list, as simple as that.

$("ul").find("*").length;

The find() method traverses DOM downwards along descendants, all the way down to the last descendant.

Note: children() method traverses a single level down the DOM tree.

Xcode 4 - "Valid signing identity not found" error on provisioning profiles on a new Macintosh install

I faced this problem this morning when I just opened an old app with a different certificate and allowed its access to the keychain. My other app that was working pretty well, stopped working with this error. I've been pulling out my hair till now, when I simply did this:

Xcode Menu > Preferences > Accounts > THE_APPLE_ID_THAT_YOU_ARE_USING > View Details

In the new window, at the bottom left of the Signing identities press the + button and select iOS Development. It'll re-add the identity, and after that my problem is fixed now and the app is running on the device again.

enter image description here

Factorial using Recursion in Java

Well variable "result" is a local variable. When fact() method is called from "main" method variable "result" is stored in different variable.

Also line : result = fact(n-1) * n; 

here logic is finding factorial using recursion. Recursion in java is a procedure in which a method calls itself.

Meanwhile you can refer this resource on factorial of a number using recursion.

How to find length of dictionary values

Lets do some experimentation, to see how we could get/interpret the length of different dict/array values in a dict.

create our test dict, see list and dict comprehensions:

>>> my_dict = {x:[i for i in range(x)] for x in range(4)}
>>> my_dict
{0: [], 1: [0], 2: [0, 1], 3: [0, 1, 2]}

Get the length of the value of a specific key:

>>> my_dict[3]
[0, 1, 2]
>>> len(my_dict[3])
3

Get a dict of the lengths of the values of each key:

>>> key_to_value_lengths = {k:len(v) for k, v in my_dict.items()}
{0: 0, 1: 1, 2: 2, 3: 3}
>>> key_to_value_lengths[2]
2

Get the sum of the lengths of all values in the dict:

>>> [len(x) for x in my_dict.values()]
[0, 1, 2, 3]
>>> sum([len(x) for x in my_dict.values()])
6

jQuery add class .active on menu

An easier way for me was:

var activeurl = window.location;
$('a[href="'+activeurl+'"]').parent('li').addClass('active');

because my links go to absolute url, but if your links are relative then you can use:

 window.location**.pathname**

how to deal with google map inside of a hidden div (Updated picture)

Just as John Doppelmann and HoffZ have indicated, put all code together just as follows in your div showing function or onclick event:

setTimeout(function(){
var center = map.getCenter();
google.maps.event.trigger(map, 'resize');
map.setCenter(center);
});

It worked perfectly for me

Two divs side by side - Fluid display

You can also use the Grid View its also Responsive its something like this:

#wrapper {
   width: auto;
    height: auto;
    box-sizing: border-box;
    display: grid;
    grid-auto-flow: row;
    grid-template-columns: repeat(6, 1fr);
}

#left{
    text-align: left;
    grid-column: 1/4;
}

#right {
    text-align: right;
    grid-column: 4/6;
}

and the HTML should look like this :

<div id="wrapper">
<div id="left" > ...some awesome stuff </div>
<div id="right" > ...some awesome stuff </div>
</div>

here is a link for more information:

https://www.w3schools.com/css/css_rwd_grid.asp

im quite new but i thougt i could share my little experience

image processing to improve tesseract OCR accuracy

  1. fix DPI (if needed) 300 DPI is minimum
  2. fix text size (e.g. 12 pt should be ok)
  3. try to fix text lines (deskew and dewarp text)
  4. try to fix illumination of image (e.g. no dark part of image)
  5. binarize and de-noise image

There is no universal command line that would fit to all cases (sometimes you need to blur and sharpen image). But you can give a try to TEXTCLEANER from Fred's ImageMagick Scripts.

If you are not fan of command line, maybe you can try to use opensource scantailor.sourceforge.net or commercial bookrestorer.

Visual Studio 64 bit?

Is there any 64 bit Visual Studio at all?

Yes literally there is one called "Visual Studio" and is 64bit, but well,, on Mac not on Windows

Why not?

Decision making is electro-chemical reaction made in our brain and that have an activation point (Nerdest answer I can come up with, but follow). Same situation happened in history: Windows 64!...

So in order to answer this fully I want you to remember old days. Imagine reasons for "why not we see 64bit Windows" are there at the time. I think at the time for Windows64 they had exact same reasons others have enlisted here about "reasons why not 64bit VS on windows" were on "reasons why not 64bit Windows" too. Then why they did start development for Windows 64bit? Simple! If they didn't succeed in making 64bit Windows I bet M$ would have been a history nowadays. If same reasons forcing M$ making 64bit Windows starts to appear on need for 64Bit VS then I bet we will see 64bit VS, even though very same reasons everyone else here enlisted will stay same! In time the limitations of 32bit may hit VS as well, so most likely something like below start to happen:

  • Visual Studio will drop 32bit support and become 64bit,
  • Visual Studio Code will take it's place instead,
  • Visual Studio will have similar functionality like WOW64 for old extensions which is I believe unlikely to happen.

I put my bets on Visual Studio Code taking the place in time; I guess bifurcation point for it will be some CPU manufacturer X starts to compete x86_64 architecture taking its place on mainstream market for laptop and/or workstation,

Convert a JSON string to object in Java ME?

I used a few of them and my favorite is,

http://code.google.com/p/json-simple/

The library is very small so it's perfect for J2ME.

You can parse JSON into Java object in one line like this,

JSONObject json = (JSONObject)new JSONParser().parse("{\"name\":\"MyNode\", \"width\":200, \"height\":100}");
System.out.println("name=" + json.get("name"));
System.out.println("width=" + json.get("width"));

How to do a non-greedy match in grep?

I know that its a bit of a dead post but I just noticed that this works. It removed both clean-up and cleanup from my output.

> grep -v -e 'clean\-\?up'
> grep --version grep (GNU grep) 2.20

How to pass arguments within docker-compose?

This can now be done as of docker-compose v2+ as part of the build object;

docker-compose.yml

version: '2'
services:
    my_image_name:
        build:
            context: . #current dir as build context
            args:
                var1: 1
                var2: c

See the docker compose docs.

In the above example "var1" and "var2" will be sent to the build environment.

Note: any env variables (specified by using the environment block) which have the same name as args variable(s) will override that variable.

mySQL convert varchar to date

select date_format(str_to_date('31/12/2010', '%d/%m/%Y'), '%Y%m'); 

or

select date_format(str_to_date('12/31/2011', '%m/%d/%Y'), '%Y%m'); 

hard to tell from your example

What is "git remote add ..." and "git push origin master"?

  1. The .git at the end of the repository name is just a convention. Typically, on git servers repositories are kept in directories named project.git. The git client and protocol honours this convention by testing for project.git when only project is specified.

  2. git://[email protected]/peter/first_app.git is not a valid git url. git repositories can be identified and accessed via various url schemes specified here. [email protected]:peter/first_app.git is the ssh url mentioned on that page.

  3. git is flexible. It allows you to track your local branch against almost any branch of any repository. While master (your local default branch) tracking origin/master (the remote default branch) is a popular situation, it is not universal. Many a times you may not want to do that. This is why the first git push is so verbose. It tells git what to do with the local master branch when you do a git pull or a git push.

  4. The default for git push and git pull is to work with the current branch's remote. This is a better default than origin master. The way git push determines this is explained here.

git is fairly elegant and comprehensible but there is a learning curve to walk through.

Find the max of 3 numbers in Java with different data types

you can use this:

 Collections.max(Arrays.asList(1,2,3,4));

or create a function

public static int max(Integer... vals) {
    return Collections.max(Arrays.asList(vals)); 
}

Convert varchar dd/mm/yyyy to dd/mm/yyyy datetime

Try this code:

CONVERT(varchar(15), date_started, 103)

Oracle SELECT TOP 10 records

With regards to the poor performance there are any number of things it could be, and it really ought to be a separate question. However, there is one obvious thing that could be a problem:

WHERE TO_CHAR(HISTORY_DATE, 'DD.MM.YYYY') = '06.02.2009') 

If HISTORY_DATE really is a date column and if it has an index then this rewrite will perform better:

WHERE HISTORY_DATE = TO_DATE ('06.02.2009', 'DD.MM.YYYY')  

This is because a datatype conversion disables the use of a B-Tree index.

How do I use a pipe to redirect the output of one command to the input of another?

You can also run exactly same command at Cmd.exe command-line using PowerShell. I'd go with this approach for simplicity...

C:\>PowerShell -Command "temperature | prismcom.exe usb"

Please read up on Understanding the Windows PowerShell Pipeline

You can also type in C:\>PowerShell at the command-line and it'll put you in PS C:\> mode instanctly, where you can directly start writing PS.

How to convert Set<String> to String[]?

Use the Set#toArray(IntFunction<T[]>) method taking an IntFunction as generator.

String[] GPXFILES1 = myset.toArray(String[]::new);

If you're not on Java 11 yet, then use the Set#toArray(T[]) method taking a typed array argument of the same size.

String[] GPXFILES1 = myset.toArray(new String[myset.size()]);

While still not on Java 11, and you can't guarantee that myset is unmodifiable at the moment of conversion to array, then better specify an empty typed array.

String[] GPXFILES1 = myset.toArray(new String[0]);

How to show "if" condition on a sequence diagram?

If you paste

A.do() {
  if (condition1) {
   X.doSomething
  } else if (condition2) {
   Y.doSomethingElse
  } else {
   donotDoAnything
  }
}

onto https://www.zenuml.com. It will generate a diagram for you.If/else sequence diagram

Getting number of days in a month

You want DateTime.DaysInMonth:

int days = DateTime.DaysInMonth(year, month);

Obviously it varies by year, as sometimes February has 28 days and sometimes 29. You could always pick a particular year (leap or not) if you want to "fix" it to one value or other.

app.config for a class library

There is no automatic addition of app.config file when you add a class library project to your solution.

To my knowledge, there is no counter indication about doing so manualy. I think this is a common usage.

About log4Net config, you don't have to put the config into app.config, you can have a dedicated conf file in your project as well as an app.config file at the same time.

this link http://logging.apache.org/log4net/release/manual/configuration.html will give you examples about both ways (section in app.config and standalone log4net conf file)

How to install cron

On CentOS/RHEL:

yum install cronie

How to unsubscribe to a broadcast event in angularJS. How to remove function registered via $on

After debugging the code, i created my own function just like "blesh"'s answer. So this is what i did

MyModule = angular.module('FIT', [])
.run(function ($rootScope) {
        // Custom $off function to un-register the listener.
        $rootScope.$off = function (name, listener) {
            var namedListeners = this.$$listeners[name];
            if (namedListeners) {
                // Loop through the array of named listeners and remove them from the array.
                for (var i = 0; i < namedListeners.length; i++) {
                    if (namedListeners[i] === listener) {
                        return namedListeners.splice(i, 1);
                    }
                }
            }
        }
});

so by attaching my function to $rootscope now it is available to all my controllers.

and in my code I am doing

$scope.$off("onViewUpdated", callMe);

Thanks

EDIT: The AngularJS way to do this is in @LiviuT's answer! But if you want to de-register the listener in another scope and at the same time want to stay away from creating local variables to keep references of de-registeration function. This is a possible solution.

Printing Batch file results to a text file

Have you tried moving DEL %FILE%.txt% to after @echo %FILE% deleted. >> results.txt so that it looks like this?

@echo %FILE% deleted. >> results.txt
DEL %FILE%.txt

Reference — What does this symbol mean in PHP?

Spaceship Operator <=> (Added in PHP 7)

Examples for <=> Spaceship operator (PHP 7, Source: PHP Manual):

Integers, Floats, Strings, Arrays & objects for Three-way comparison of variables.

// Integers
echo 10 <=> 10; // 0
echo 10 <=> 20; // -1
echo 20 <=> 10; // 1

// Floats
echo 1.5 <=> 1.5; // 0
echo 1.5 <=> 2.5; // -1
echo 2.5 <=> 1.5; // 1

// Strings
echo "a" <=> "a"; // 0
echo "a" <=> "b"; // -1
echo "b" <=> "a"; // 1
// Comparison is case-sensitive
echo "B" <=> "a"; // -1

echo "a" <=> "aa"; // -1
echo "zz" <=> "aa"; // 1

// Arrays
echo [] <=> []; // 0
echo [1, 2, 3] <=> [1, 2, 3]; // 0
echo [1, 2, 3] <=> []; // 1
echo [1, 2, 3] <=> [1, 2, 1]; // 1
echo [1, 2, 3] <=> [1, 2, 4]; // -1

// Objects
$a = (object) ["a" => "b"]; 
$b = (object) ["a" => "b"]; 
echo $a <=> $b; // 0

$a = (object) ["a" => "b"]; 
$b = (object) ["a" => "c"]; 
echo $a <=> $b; // -1

$a = (object) ["a" => "c"]; 
$b = (object) ["a" => "b"]; 
echo $a <=> $b; // 1

// only values are compared
$a = (object) ["a" => "b"]; 
$b = (object) ["b" => "b"]; 
echo $a <=> $b; // 1

JS. How to replace html element with another element/text, represented in string?

As the Jquery replaceWith() code was too bulky, tricky and complicated, here's my own solution. =)

The best way is to use outerHTML property, but it is not crossbrowsered yet, so I did some trick, weird enough, but simple.

Here is the code

var str = '<a href="http://www.com">item to replace</a>'; //it can be anything
var Obj = document.getElementById('TargetObject'); //any element to be fully replaced
if(Obj.outerHTML) { //if outerHTML is supported
    Obj.outerHTML=str; ///it's simple replacement of whole element with contents of str var
}
else { //if outerHTML is not supported, there is a weird but crossbrowsered trick
    var tmpObj=document.createElement("div");
    tmpObj.innerHTML='<!--THIS DATA SHOULD BE REPLACED-->';
    ObjParent=Obj.parentNode; //Okey, element should be parented
    ObjParent.replaceChild(tmpObj,Obj); //here we placing our temporary data instead of our target, so we can find it then and replace it into whatever we want to replace to
    ObjParent.innerHTML=ObjParent.innerHTML.replace('<div><!--THIS DATA SHOULD BE REPLACED--></div>',str);
}

That's all

The localhost page isn’t working localhost is currently unable to handle this request. HTTP ERROR 500

Here's an answer to a 2-year old question in case it helps anyone else with the same problem.

Based upon the information you've provided, a permissions issue on the file (or files) would be one cause of the same 500 Internal Server Error.

To check whether this is the problem (if you can't get more detailed information on the error), navigate to the directory in Terminal and run the following command:

ls -la

If you see limited permissions - e.g. -rw-------@ against your file, then that's your problem.

The solution then is to run chmod 644 on the problem file(s) or chmod 755 on the directories. See this answer - How do I set chmod for a folder and all of its subfolders and files? - for a detailed explanation of how to change permissions.

By way of background, I had precisely the same problem as you did on some files that I had copied over from another Mac via Google Drive, which transfer had stripped most of the permissions from the files.

The screenshot below illustrates. The index.php file with the -rw-------@ permissions generates a 500 Internal Server Error, while the index_finstuff.php (precisely the same content!) with -rw-r--r--@ permissions is fine. Changing the permissions on the index.php immediately resolves the problem.

In other words, your PHP code and the server may both be fine. However, the limited read permissions on the file may be forbidding the server from displaying the content, causing the 500 Internal Server Error message to be displayed instead.

enter image description here

Subset dataframe by multiple logical conditions of rows to remove

This answer is more meant to explain why, not how. The '==' operator in R is vectorized in a same way as the '+' operator. It matches the elements of whatever is on the left side to the elements of whatever is on the right side, per element. For example:

> 1:3 == 1:3
[1] TRUE TRUE TRUE

Here the first test is 1==1 which is TRUE, the second 2==2 and the third 3==3. Notice that this returns a FALSE in the first and second element because the order is wrong:

> 3:1 == 1:3
[1] FALSE  TRUE FALSE

Now if one object is smaller then the other object then the smaller object is repeated as much as it takes to match the larger object. If the size of the larger object is not a multiplication of the size of the smaller object you get a warning that not all elements are repeated. For example:

>  1:2 == 1:3
[1]  TRUE  TRUE FALSE
Warning message:
In 1:2 == 1:3 :
  longer object length is not a multiple of shorter object length

Here the first match is 1==1, then 2==2, and finally 1==3 (FALSE) because the left side is smaller. If one of the sides is only one element then that is repeated:

> 1:3 == 1
[1]  TRUE FALSE FALSE

The correct operator to test if an element is in a vector is indeed '%in%' which is vectorized only to the left element (for each element in the left vector it is tested if it is part of any object in the right element).

Alternatively, you can use '&' to combine two logical statements. '&' takes two elements and checks elementwise if both are TRUE:

> 1:3 == 1 & 1:3 != 2
[1]  TRUE FALSE FALSE

Spring Boot Java Config Set Session Timeout

server.session.timeout in the application.properties file is now deprecated. The correct setting is:

server.servlet.session.timeout=60s

Also note that Tomcat will not allow you to set the timeout any less than 60 seconds. For details about that minimum setting see https://github.com/spring-projects/spring-boot/issues/7383.

Bash script and /bin/bash^M: bad interpreter: No such file or directory

I develop on Windows and Mac/Linux at the same time and I avoid this ^M-error by simply running my scripts as I do in Windows:

$ php ./my_script

No need to change line endings.

Gradle, Android and the ANDROID_HOME SDK location

I came across a similar problem. Somehow, I did not have a build folder in my project. By copying this folder from another project to my project I was having an issue with, this fixed this problem.

Invalid argument supplied for foreach()

$values = get_values();

foreach ((array) $values as $value){
  ...
}

Problem is always null and Casting is in fact the cleaning solution.

When to use setAttribute vs .attribute= in JavaScript?

"When to use setAttribute vs .attribute= in JavaScript?"

A general rule is to use .attribute and check if it works on the browser.

..If it works on the browser, you're good to go.

..If it doesn't, use .setAttribute(attribute, value) instead of .attribute for that attribute.

Rinse-repeat for all attributes.

Well, if you're lazy you can simply use .setAttribute. That should work fine on most browsers. (Though browsers that support .attribute can optimize it better than .setAttribute(attribute, value).)

Spring default behavior for lazy-init

For those coming here and are using Java config you can set the Bean to lazy-init using annotations like this:

In the configuration class:

@Configuration
// @Lazy - For all Beans to load lazily
public class AppConf {

    @Bean
    @Lazy
    public Demo demo() {
        return new Demo();
    }
}

For component scanning and auto-wiring:

@Component
@Lazy
public class Demo {
    ....
    ....
}

@Component
public class B {

    @Autowired
    @Lazy // If this is not here, Demo will still get eagerly instantiated to satisfy this request.
    private Demo demo;

    .......
 }

Remove all occurrences of a value from a list?

About the speed!

import time
s_time = time.time()

print 'start'
a = range(100000000)
del a[:]
print 'finished in %0.2f' % (time.time() - s_time)
# start
# finished in 3.25

s_time = time.time()
print 'start'
a = range(100000000)
a = []
print 'finished in %0.2f' % (time.time() - s_time)
# start
# finished in 2.11

Apply function to pandas groupby

apply takes a function to apply to each value, not the series, and accepts kwargs. So, the values do not have the .size() method.

Perhaps this would work:

from pandas import *

d = {"my_label": Series(['A','B','A','C','D','D','E'])}
df = DataFrame(d)


def as_perc(value, total):
    return value/float(total)

def get_count(values):
    return len(values)

grouped_count = df.groupby("my_label").my_label.agg(get_count)
data = grouped_count.apply(as_perc, total=df.my_label.count())

The .agg() method here takes a function that is applied to all values of the groupby object.

What is the difference between '/' and '//' when used for division?

The double slash, //, is floor division:

>>> 7//3
2

How do I left align these Bootstrap form items?

Instead of altering the original bootstrap css class create a new css file that will override the default style.

Make sure you include the new css file after including the bootstrap.css file.

In the new css file do

.form-horizontal .control-label{
   text-align:left !important; 
}

HttpRequest maximum allowable size in tomcat?

The full answer

1. The default (fresh install of tomcat)

When you download tomcat from their official website (of today that's tomcat version 9.0.26), all the apps you installed to tomcat can handle HTTP requests of unlimited size, given that the apps themselves do not have any limits on request size.

However, when you try to upload an app in tomcat's manager app, that app has a default war file limit of 50MB. If you're trying to install Jenkins for example which is 77 MB as ot today, it will fail.

2. Configure tomcat's per port http request size limit

Tomcat itself has size limit for each port, and this is defined in conf\server.xml. This is controlled by maxPostSize attribute of each Connector(port). If this attribute does not exist, which it is by default, there is no limit on the request size.

To add a limit to a specific port, set a byte size for the attribute. For example, the below config for the default 8080 port limits request size to 200 MB. This means that all the apps installed under port 8080 now has the size limit of 200MB

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443"
           maxPostSize="209715200" />

3. Configure app level size limit

After passing the port level size limit, you can still configure app level limit. This also means that app level limit should be less than port level limit. The limit can be done through annotation within each servlet, or in the web.xml file. Again, if this is not set at all, there is no limit on request size.

To set limit through java annotation

@WebServlet("/uploadFiles")
@MultipartConfig( fileSizeThreshold = 0, maxFileSize = 209715200, maxRequestSize = 209715200)
public class FileUploadServlet extends HttpServlet {

    public void doPost(HttpServletRequest request, HttpServletResponse response) {
        // ...
    }
}

To set limit through web.xml

<web-app>
  ...
  <servlet>
    ...
    <multipart-config>
      <file-size-threshold>0</file-size-threshold>
      <max-file-size>209715200</max-file-size>
      <max-request-size>209715200</max-request-size>
    </multipart-config>
    ...
  </servlet>
  ...
</web-app>

4. Appendix - If you see file upload size error when trying to install app through Tomcat's Manager app

Tomcat's Manager app (by default localhost:8080/manager) is nothing but a default web app. By default that app has a web.xml configuration of request limit of 50MB. To install (upload) app with size greater than 50MB through this manager app, you have to change the limit. Open the manager app's web.xml file from webapps\manager\WEB-INF\web.xml and follow the above guide to change the size limit and finally restart tomcat.

Difference between \b and \B in regex

The confusion stems from your thinking \b matches spaces (probably because "b" suggests "blank").

\b matches the empty string at the beginning or end of a word. \B matches the empty string not at the beginning or end of a word. The key here is that "-" is not a part of a word. So <left>-<right> matches \b-\b because there are word boundaries on either side of the -. On the other hand for <left> - <right> (note the spaces), there are not word boundaries on either side of the dash. The word boundaries are one space further left and right.

On the other hand, when searching for \bcat\b word boundaries behave more intuitively, and it matches " cat " as expected.

unable to remove file that really exists - fatal: pathspec ... did not match any files

I know this is not the OP's problem, but I ran into the same error with an entirely different basis, so I just wanted to drop it here in case anyone else has the same. This is Windows-specific, and I assume does not affect Linux users.

I had a LibreOffice doc file, call it final report.odt. I later changed its case to Final Report.odt. In Windows, this doesn't even count as a rename. final report.odt, Final Report.odt, FiNaL RePoRt.oDt are all the same. In Linux, these are all distinct.

When I eventually went to git rm "Final Report.odt" and got the "pathspec did not match any files" error. Only when I use the original casing at the time the file was added -- git rm "final report.odt" -- did it work.

Lesson learned: to change the case I should have instead done:

git mv "final report.odt" temp.odt
git mv temp.odt "Final Report.odt"

Again, that wasn't the problem for the OP here; and wouldn't affect a Linux user, as his posts shows he clearly is. I'm just including it for others who may have this problem in Windows git and stumble onto this question.

How do I install an R package from source?

From cran, you can install directly from a github repository address. So if you want the package at https://github.com/twitter/AnomalyDetection:

library(devtools)
install_github("twitter/AnomalyDetection")

does the trick.

Download image with JavaScript

The problem is that jQuery doesn't trigger the native click event for <a> elements so that navigation doesn't happen (the normal behavior of an <a>), so you need to do that manually. For almost all other scenarios, the native DOM event is triggered (at least attempted to - it's in a try/catch).

To trigger it manually, try:

var a = $("<a>")
    .attr("href", "http://i.stack.imgur.com/L8rHf.png")
    .attr("download", "img.png")
    .appendTo("body");

a[0].click();

a.remove();

DEMO: http://jsfiddle.net/HTggQ/

Relevant line in current jQuery source: https://github.com/jquery/jquery/blob/1.11.1/src/event.js#L332

if ( (!special._default || special._default.apply( eventPath.pop(), data ) === false) &&
        jQuery.acceptData( elem ) ) {

How to query MongoDB with "like"?

With MongoDB Compass, you need to use the strict mode syntax, as such:

{ "text": { "$regex": "^Foo.*", "$options": "i" } }

(In MongoDB Compass, it's important that you use " instead of ')

Using IF ELSE statement based on Count to execute different Insert statements

Simply use the following:

IF((SELECT count(*) FROM table)=0)
BEGIN

....

END

Install-Module : The term 'Install-Module' is not recognized as the name of a cmdlet

I didn't have the NuGet Package Provider, you can check running Get-PackageProvider:

PS C:\WINDOWS\system32> Get-PackageProvider 

Name                     Version          DynamicOptions                                                                                                                 
----                     -------          --------------                                                                                                                 
msi                      3.0.0.0          AdditionalArguments                                                                                                            
msu                      3.0.0.0                                                                                                                                         
NuGet  <NOW INSTALLED>   2.8.5.208        Destination, ...                             

The solution was installing it by running this command:

Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Force

If that fails with the error below you can copy/paste the NuGet folder from another PC (admin needed): C:\Program Files\PackageManagement\ProviderAssemblies\NuGet:

WARNING: Unable to download from URI 'https://onegetcdn.azureedge.net/providers/Microsoft.PackageManagement.NuGetProvider-2.8.5.208.dll' to ''.
WARNING: Failed to bootstrap provider 'https://onegetcdn.azureedge.net/providers/nuget-2.8.5.208.package.swidtag'.
WARNING: Failed to bootstrap provider 'nuget'.
WARNING: The specified PackageManagement provider 'NuGet' is not available.
PackageManagement\Install-PackageProvider : Unable to download from URI 
'https://onegetcdn.azureedge.net/providers/Microsoft.PackageManagement.NuGetProvider-2.8.5.208.dll' to ''.
At C:\Program Files\WindowsPowerShell\Modules\PowerShellGet\PSModule.psm1:6463 char:21
+             $null = PackageManagement\Install-PackageProvider -Name $script:NuGe ...

ITextSharp insert text to an existing pdf

Here is a method that uses stamper and absolute coordinates showed in the different PDF clients (Adobe, FoxIt and etc. )

public static void AddTextToPdf(string inputPdfPath, string outputPdfPath, string textToAdd, System.Drawing.Point point)
    {
        //variables
        string pathin = inputPdfPath;
        string pathout = outputPdfPath;

        //create PdfReader object to read from the existing document
        using (PdfReader reader = new PdfReader(pathin))
        //create PdfStamper object to write to get the pages from reader 
        using (PdfStamper stamper = new PdfStamper(reader, new FileStream(pathout, FileMode.Create)))
        {
            //select two pages from the original document
            reader.SelectPages("1-2");

            //gettins the page size in order to substract from the iTextSharp coordinates
            var pageSize = reader.GetPageSize(1);

            // PdfContentByte from stamper to add content to the pages over the original content
            PdfContentByte pbover = stamper.GetOverContent(1);

            //add content to the page using ColumnText
            Font font = new Font();
            font.Size = 45;

            //setting up the X and Y coordinates of the document
            int x = point.X;
            int y = point.Y;

            y = (int) (pageSize.Height - y);

            ColumnText.ShowTextAligned(pbover, Element.ALIGN_CENTER, new Phrase(textToAdd, font), x, y, 0);
        }
    }

Test for array of string type in TypeScript

Here is the most concise solution so far:

function isArrayOfStrings(value: any): boolean {
   return Array.isArray(value) && value.every(item => typeof item === "string");
}

Note that value.every will return true for an empty array. If you need to return false for an empty array, you should add value.length to the condition clause:

function isNonEmptyArrayOfStrings(value: any): boolean {
    return Array.isArray(value) && value.length && value.every(item => typeof item === "string");
}

There is no any run-time type information in TypeScript (and there won't be, see TypeScript Design Goals > Non goals, 5), so there is no way to get the type of an empty array. For a non-empty array all you can do is to check the type of its items, one by one.

How can I install a local gem?

Yup, when you do gem install, it will search the current directory first, so if your .gem file is there, it will pick it up. I found it on the gem reference, which you may find handy as well:

gem install will install the named gem. It will attempt a local installation (i.e. a .gem file in the current directory), and if that fails, it will attempt to download and install the most recent version of the gem you want.

Ruby on Rails. How do I use the Active Record .build method in a :belongs to relationship?

@article = user.articles.build(:title => "MainTitle")
@article.save

How to Logout of an Application Where I Used OAuth2 To Login With Google?

Ouath just makes the Google instance null, hence it you out of Google. Now that's how the architecture is made. Logging out of Google, if you Logout of your app is a dirty work, but can't help if the requirement stipulates the same. Hence add the following to your signOut() function. My project was an Angular 6 app:

document.location.href = "https://www.google.com/accounts/Logout?continue=https://appengine.google.com/_ah/logout?continue=http://localhost:4200";

Here localhost:4200 is the URL of my app. If your login page is xyz.com then input that.

Method List in Visual Studio Code

Visual Studio Code market place has a very nice extension named Go To Method for navigating only methods in a code file.

Hit Ctrl+Shift+P and type the install extensions and press enter

enter image description here

Now type Add to method in search box of extensions market place and press enter.

enter image description here

Click install to install the extension.

Last step is to bind a keyboard shortcut to the command workbench.action.gotoMethod to make it a real productivity thing for a developer.

How do we count rows using older versions of Hibernate (~2009)?

For older versions of Hibernate (<5.2):

Assuming the class name is Book:

return (Number) session.createCriteria("Book")
                  .setProjection(Projections.rowCount())
                  .uniqueResult();

It is at least a Number, most likely a Long.

Android: upgrading DB version and adding new table

You can use SQLiteOpenHelper's onUpgrade method. In the onUpgrade method, you get the oldVersion as one of the parameters.

In the onUpgrade use a switch and in each of the cases use the version number to keep track of the current version of database.

It's best that you loop over from oldVersion to newVersion, incrementing version by 1 at a time and then upgrade the database step by step. This is very helpful when someone with database version 1 upgrades the app after a long time, to a version using database version 7 and the app starts crashing because of certain incompatible changes.

Then the updates in the database will be done step-wise, covering all possible cases, i.e. incorporating the changes in the database done for each new version and thereby preventing your application from crashing.

For example:

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    switch (oldVersion) {
    case 1:
        String sql = "ALTER TABLE " + TABLE_SECRET + " ADD COLUMN " + "name_of_column_to_be_added" + " INTEGER";
        db.execSQL(sql);
        break;

    case 2:
        String sql = "SOME_QUERY";
        db.execSQL(sql);
        break;
    }

}

Event for Handling the Focus of the EditText

Here is the focus listener example.

editText.setOnFocusChangeListener(new OnFocusChangeListener() {
    @Override
    public void onFocusChange(View view, boolean hasFocus) {
        if (hasFocus) {
            Toast.makeText(getApplicationContext(), "Got the focus", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(getApplicationContext(), "Lost the focus", Toast.LENGTH_LONG).show();
        }
    }
});

Generating random whole numbers in JavaScript in a specific range?

Ionu? G. Stan wrote a great answer but it was a bit too complex for me to grasp. So, I found an even simpler explanation of the same concepts at https://teamtreehouse.com/community/mathfloor-mathrandom-max-min-1-min-explanation by Jason Anello.

NOTE: The only important thing you should know before reading Jason's explanation is a definition of "truncate". He uses that term when describing Math.floor(). Oxford dictionary defines "truncate" as:

Shorten (something) by cutting off the top or end.

Method with a bool return

Long version:

private bool booleanMethod () {
    if (your_condition) {
        return true;
    } else {
        return false;
    }
}

But since you are using the outcome of your condition as the result of the method you can shorten it to

private bool booleanMethod () {
    return your_condition;
}