Programs & Examples On #Ctabctrl

How to extract year and month from date in PostgreSQL without using to_char() function?

It is working for "greater than" functions not for less than.

For example:

select date_part('year',txndt)
from "table_name"
where date_part('year',txndt) > '2000' limit 10;

is working fine.

but for

select date_part('year',txndt)
from "table_name"
where date_part('year',txndt) < '2000' limit 10;

I am getting error.

Easiest way to open a download window without navigating away from the page

If the link is to a valid file url, simply assigning window.location.href will work.

However, sometimes the link is not valid, and an iFrame is required.

Do your normal event.preventDefault to prevent the window from opening, and if you are using jQuery, this will work:

$('<iframe>').attr('src', downloadThing.attr('href')).appendTo('body').on("load", function() {
   $(this).remove();
});

How to make responsive table

Pure css way to make a table fully responsive, no JavaScript is needed. Checke demo here Responsive Tables

<!DOCTYPE>
  <html>
  <head>
  <title>Responsive Table</title>
  <style> 
  /* only for demo purpose. you can remove it */
 .container{border: 1px solid #ccc; background-color: #ff0000; 
  margin: 10px auto;width: 98%; height:auto;padding:5px; text-align: center;}

 /* required */
.tablewrapper{width: 95%; overflow-y: hidden; overflow-x: auto; 
 background-color:green;  height: auto; padding: 5px;}

 /* only for demo purpose just for stlying. you can remove it */
 table { font-family: arial; font-size: 13px; padding: 2px 3px}
 table.responsive{ background-color:#1a99e6; border-collapse: collapse; 
 border-color: #fff}

tr:nth-child(1) td:nth-of-type(1){
 background:#333; color: #fff}
 tr:nth-child(1) td{
 background:#333; color: #fff; font-weight: bold;}
 table tr td:nth-child(2) {
 background:yellow;
}
 tr:nth-child(1) td:nth-of-type(2){color: #333}
 tr:nth-child(odd){ background:#ccc;}
 tr:nth-child(even){background:#fff;}
</style>
</head>
<body>

<div class="container">
<div class="tablewrapper">
<table  class="responsive" width="98%" cellpadding="4" cellspacing="1" border="1">
 <tr> 
 <td>Name</td> 
 <td>Email</td> 
 <td>Phone</td> 
 <td>Address</td> 
 <td>Contact</td> 
 <td>Mobile</td> 
 <td>Office</td> 
 <td>Home</td> 
 <td>Residency</td> 
 <td>Height</td>
 <td>Weight</td>
 <td>Color</td> 
 <td>Desease</td> 
 <td>Extra</td>
 <td>DOB</td>
 <td>Nick Name</td> 
</tr>
<tr>  
<td>RN Kushwaha</td>
<td>[email protected]</td>
<td>--</td>  
<td>Varanasi</td>
<td>-</td> 
<td>999999999</td> 
<td>022-111111</td> 
<td>-</td>
<td>India</td> 
<td>165cm</td> 
<td>58kg</td> 
<td>bright</td> 
<td>--</td> 
<td>--</td> 
<td>03/07/1986</td> 
<td>Aryan</td> 
</tr>
</table>
</div>
</div>
</body>
</html>

How to create Java gradle project

If you are using Eclipse, for an existing project (which has a build.gradle file) you can simply type gradle eclipse which will create all the Eclipse files and folders for this project.

It takes care of all the dependencies for you and adds them to the project resource path in Eclipse as well.

git revert back to certain commit

You can revert all your files under your working directory and index by typing following this command

git reset --hard <SHAsum of your commit>

You can also type

git reset --hard HEAD #your current head point

or

git reset --hard HEAD^ #your previous head point

Hope it helps

java: HashMap<String, int> not working

You can use reference type in generic arguments, not primitive type. So here you should use

Map<String, Integer> myMap = new HashMap<String, Integer>();

and store value as

myMap.put("abc", 5);

using favicon with css

There is no explicit way to change the favicon globally using CSS that I know of. But you can use a simple trick to change it on the fly.

First just name, or rename, the favicon to "favicon.ico" or something similar that will be easy to remember, or is relevant for the site you're working on. Then add the link to the favicon in the head as you usually would. Then when you drop in a new favicon just make sure it's in the same directory as the old one, and that it has the same name, and there you go!

It's not a very elegant solution, and it requires some effort. But dropping in a new favicon in one place is far easier than doing a find and replace of all the links, or worse, changing them manually. At least this way doesn't involve messing with the code.

Of course dropping in a new favicon with the same name will delete the old one, so make sure to backup the old favicon in case of disaster, or if you ever want to go back to the old design.

phpMyAdmin says no privilege to create database, despite logged in as root user

It appears to be a transient issue and fixed itself afterwards. Thanks for everyone's attention.

Random number between 0 and 1 in python

RTM

From the docs for the Python random module:

Functions for integers:

random.randrange(stop)
random.randrange(start, stop[, step])

    Return a randomly selected element from range(start, stop, step).
    This is equivalent to choice(range(start, stop, step)), but doesn’t
    actually build a range object.

That explains why it only gives you 0, doesn't it. range(0,1) is [0]. It is choosing from a list consisting of only that value.

Also from those docs:

random.random()    
    Return the next random floating point number in the range [0.0, 1.0).

But if your inclusion of the numpy tag is intentional, you can generate many random floats in that range with one call using a np.random function.

Redirect echo output in shell script to logfile

LOG_LOCATION="/path/to/logs"    
exec >> $LOG_LOCATION/mylogfile.log 2>&1

String Padding in C

The function itself looks fine to me. The problem could be that you aren't allocating enough space for your string to pad that many characters onto it. You could avoid this problem in the future by passing a size_of_string argument to the function and make sure you don't pad the string when the length is about to be greater than the size.

div inside php echo

You can use the below sample, also you dont need the else clause to print nothing!

 <?php if ( ($cart->count_product) > 0) { ?>
           <div class="my_class">
               <?php print $cart->count_product; ?> 
           </div>
 <?php } ?>

What database does Google use?

As others have mentioned, Google uses a homegrown solution called BigTable and they've released a few papers describing it out into the real world.

The Apache folks have an implementation of the ideas presented in these papers called HBase. HBase is part of the larger Hadoop project which according to their site "is a software platform that lets one easily write and run applications that process vast amounts of data." Some of the benchmarks are quite impressive. Their site is at http://hadoop.apache.org.

How do I add files and folders into GitHub repos?

If you want to add an empty folder you can add a '.keep' file in your folder.

This is because git does not care about folders.

The transaction log for database is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc column in sys.databases

As an aside, it is always a good practice (and possibly a solution for this type of issue) to delete a large number of rows by using batches:

WHILE EXISTS (SELECT 1 
              FROM   YourTable 
              WHERE  <yourCondition>) 
  DELETE TOP(10000) FROM YourTable 
  WHERE  <yourCondition>

How to set the size of a column in a Bootstrap responsive table

you can use the following Bootstrap class with

<tr class="w-25">

</tr>

for more details check the following page https://getbootstrap.com/docs/4.1/utilities/sizing/

Generate random numbers uniformly over an entire range

Check what RAND_MAX is on your system -- I'm guessing it is only 16 bits, and your range is too big for it.

Beyond that see this discussion on: Generating Random Integers within a Desired Range and the notes on using (or not) the C rand() function.

Does Python have a string 'contains' substring method?

in Python strings and lists

Here are a few useful examples that speak for themselves concerning the in method:

"foo" in "foobar"
True

"foo" in "Foobar"
False

"foo" in "Foobar".lower()
True

"foo".capitalize() in "Foobar"
True

"foo" in ["bar", "foo", "foobar"]
True

"foo" in ["fo", "o", "foobar"]
False

["foo" in a for a in ["fo", "o", "foobar"]]
[False, False, True]

Caveat. Lists are iterables, and the in method acts on iterables, not just strings.

Bridged networking not working in Virtualbox under Windows 10

My very simple solution that worked: select another networkcard!

  1. Make sure your guest is shut down
  2. Goto the guest Settings > Network > Adavanced
  3. Change the Adapter Type to another adapter.
  4. Start your guest and check if you got a decent IP for your network.

If it doesn't work, repeat steps and try yet another network adapter. The very basic PCnet adapters have a high succes-rate.

Good luck.

How exactly does the python any() function work?

Simply saying, any() does this work : according to the condition even if it encounters one fulfilling value in the list, it returns true, else it returns false.

list = [2,-3,-4,5,6]

a = any(x>0 for x in lst)

print a:
True


list = [2,3,4,5,6,7]

a = any(x<0 for x in lst)

print a:
False

Spring Security redirect to previous page after successful login

I have following solution and it worked for me.

Whenever login page is requested, write the referer value to the session:

@RequestMapping(value="/login", method = RequestMethod.GET)
public String login(ModelMap model,HttpServletRequest request) {

    String referrer = request.getHeader("Referer");
    if(referrer!=null){
        request.getSession().setAttribute("url_prior_login", referrer);
    }
    return "user/login";
}

Then, after successful login custom implementation of SavedRequestAwareAuthenticationSuccessHandler will redirect user to the previous page:

HttpSession session = request.getSession(false);
if (session != null) {
    url = (String) request.getSession().getAttribute("url_prior_login");
}

Redirect the user:

if (url != null) {
    response.sendRedirect(url);
}

Disable button in WPF?

I know this isn't as elegant as the other posts, but it's a more straightforward xaml/codebehind example of how to accomplish the same thing.

Xaml:

<StackPanel Orientation="Horizontal">
   <TextBox Name="TextBox01" VerticalAlignment="Top" HorizontalAlignment="Left" Width="70" />
   <Button Name="Button01" VerticalAlignment="Top" HorizontalAlignment="Left" Margin="10,0,0,0" />
</StackPanel>

CodeBehind:

Private Sub Window1_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded

        Button01.IsEnabled = False
        Button01.Content = "I am Disabled"

End Sub

Private Sub TextBox01_TextChanged(ByVal sender As Object, ByVal e As System.Windows.Controls.TextChangedEventArgs) Handles TextBox01.TextChanged

        If TextBox01.Text.Trim.Length > 0 Then
            Button01.IsEnabled = True
            Button01.Content = "I am Enabled"
        Else
            Button01.IsEnabled = False
            Button01.Content = "I am Disabled"
        End If

End Sub

How to validate an Email in PHP?

You can use the filter_var() function, which gives you a lot of handy validation and sanitization options.

filter_var($email, FILTER_VALIDATE_EMAIL)

If you don't want to change your code that relied on your function, just do:

function isValidEmail($email){ 
    return filter_var($email, FILTER_VALIDATE_EMAIL) !== false;
}

Note: For other uses (where you need Regex), the deprecated ereg function family (POSIX Regex Functions) should be replaced by the preg family (PCRE Regex Functions). There are a small amount of differences, reading the Manual should suffice.

Update 1: As pointed out by @binaryLV:

PHP 5.3.3 and 5.2.14 had a bug related to FILTER_VALIDATE_EMAIL, which resulted in segfault when validating large values. Simple and safe workaround for this is using strlen() before filter_var(). I'm not sure about 5.3.4 final, but it is written that some 5.3.4-snapshot versions also were affected.

This bug has already been fixed.

Update 2: This method will of course validate bazmega@kapa as a valid email address, because in fact it is a valid email address. But most of the time on the Internet, you also want the email address to have a TLD: [email protected]. As suggested in this blog post (link posted by @Istiaque Ahmed), you can augment filter_var() with a regex that will check for the existence of a dot in the domain part (will not check for a valid TLD though):

function isValidEmail($email) {
    return filter_var($email, FILTER_VALIDATE_EMAIL) 
        && preg_match('/@.+\./', $email);
}

As @Eliseo Ocampos pointed out, this problem only exists before PHP 5.3, in that version they changed the regex and now it does this check, so you do not have to.

ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: 'undefined'

If you are using <ng-content> with *ngIf you are bound to fall into this loop.

Only way out I found was to change *ngIf to display:none functionality

How to install the JDK on Ubuntu Linux

I recommend JavaPackage.

It's very simple. You just need to follow the instructions to create a .deb package from the Oracle tar.gz file.

The executable gets signed with invalid entitlements in Xcode

(Xcode 7.3.1) I had this issue with only one device in particular. What fixed it for me was to run the app from a colleague's computer(successfully) and after that I stopped getting this error on my computer.

embedding image in html email

I know this is an old post, but the current answers dont address the fact that outlook and many other email providers dont support inline images or CID images. The most effective way to place images in emails is to host it online and place a link to it in the email. For small email lists a public dropbox works fine. This also keeps the email size down.

How to create an Array, ArrayList, Stack and Queue in Java?

Without more details as to what the question is exactly asking, I am going to answer the title of the question,

Create an Array:

String[] myArray = new String[2];
int[] intArray = new int[2];

// or can be declared as follows
String[] myArray = {"this", "is", "my", "array"};
int[] intArray = {1,2,3,4};

Create an ArrayList:

ArrayList<String> myList = new ArrayList<String>();
myList.add("Hello");
myList.add("World");

ArrayList<Integer> myNum = new ArrayList<Integer>();
myNum.add(1);
myNum.add(2);

This means, create an ArrayList of String and Integer objects. You cannot use int because thats a primitive data types, see the link for a list of primitive data types.

Create a Stack:

Stack myStack = new Stack();
// add any type of elements (String, int, etc..)
myStack.push("Hello");
myStack.push(1);

Create an Queue: (using LinkedList)

Queue<String> myQueue = new LinkedList<String>();
Queue<Integer> myNumbers = new LinkedList<Integer>();
myQueue.add("Hello");
myQueue.add("World");
myNumbers.add(1);
myNumbers.add(2);

Same thing as an ArrayList, this declaration means create an Queue of String and Integer objects.


Update:

In response to your comment from the other given answer,

i am pretty confused now, why are using string. and what does <String> means

We are using String only as a pure example, but you can add any other object, but the main point is that you use an object not a primitive type. Each primitive data type has their own primitive wrapper class, see link for list of primitive data type's wrapper class.

I have posted some links to explain the difference between the two, but here are a list of primitive types

  • byte
  • short
  • char
  • int
  • long
  • boolean
  • double
  • float

Which means, you are not allowed to make an ArrayList of integer's like so:

ArrayList<int> numbers = new ArrayList<int>(); 
           ^ should be an object, int is not an object, but Integer is!
ArrayList<Integer> numbers = new ArrayList<Integer>();
            ^ perfectly valid

Also, you can use your own objects, here is my Monster object I created,

public class Monster {
   String name = null;
   String location = null;
   int age = 0;

public Monster(String name, String loc, int age) { 
   this.name = name;
   this.loc = location;
   this.age = age;
 }

public void printDetails() {
   System.out.println(name + " is from " + location +
                                     " and is " + age + " old.");
 }
} 

Here we have a Monster object, but now in our Main.java class we want to keep a record of all our Monster's that we create, so let's add them to an ArrayList

public class Main {
    ArrayList<Monster> myMonsters = new ArrayList<Monster>();

public Main() {
    Monster yetti = new Monster("Yetti", "The Mountains", 77);
    Monster lochness = new Monster("Lochness Monster", "Scotland", 20);

    myMonsters.add(yetti); // <-- added Yetti to our list
    myMonsters.add(lochness); // <--added Lochness to our list
  
    for (Monster m : myMonsters) {
        m.printDetails();
     }
   }

public static void main(String[] args) {
    new Main();
 }
}

(I helped my girlfriend's brother with a Java game, and he had to do something along those lines as well, but I hope the example was well demonstrated)

How to calculate rolling / moving average using NumPy / SciPy?

NumPy's lack of a particular domain-specific function is perhaps due to the Core Team's discipline and fidelity to NumPy's prime directive: provide an N-dimensional array type, as well as functions for creating, and indexing those arrays. Like many foundational objectives, this one is not small, and NumPy does it brilliantly.

The (much) larger SciPy contains a much larger collection of domain-specific libraries (called subpackages by SciPy devs)--for instance, numerical optimization (optimize), signal processsing (signal), and integral calculus (integrate).

My guess is that the function you are after is in at least one of the SciPy subpackages (scipy.signal perhaps); however, i would look first in the collection of SciPy scikits, identify the relevant scikit(s) and look for the function of interest there.

Scikits are independently developed packages based on NumPy/SciPy and directed to a particular technical discipline (e.g., scikits-image, scikits-learn, etc.) Several of these were (in particular, the awesome OpenOpt for numerical optimization) were highly regarded, mature projects long before choosing to reside under the relatively new scikits rubric. The Scikits homepage liked to above lists about 30 such scikits, though at least several of those are no longer under active development.

Following this advice would lead you to scikits-timeseries; however, that package is no longer under active development; In effect, Pandas has become, AFAIK, the de facto NumPy-based time series library.

Pandas has several functions that can be used to calculate a moving average; the simplest of these is probably rolling_mean, which you use like so:

>>> # the recommended syntax to import pandas
>>> import pandas as PD
>>> import numpy as NP

>>> # prepare some fake data:
>>> # the date-time indices:
>>> t = PD.date_range('1/1/2010', '12/31/2012', freq='D')

>>> # the data:
>>> x = NP.arange(0, t.shape[0])

>>> # combine the data & index into a Pandas 'Series' object
>>> D = PD.Series(x, t)

Now, just call the function rolling_mean passing in the Series object and a window size, which in my example below is 10 days.

>>> d_mva = PD.rolling_mean(D, 10)

>>> # d_mva is the same size as the original Series
>>> d_mva.shape
    (1096,)

>>> # though obviously the first w values are NaN where w is the window size
>>> d_mva[:3]
    2010-01-01         NaN
    2010-01-02         NaN
    2010-01-03         NaN

verify that it worked--e.g., compared values 10 - 15 in the original series versus the new Series smoothed with rolling mean

>>> D[10:15]
     2010-01-11    2.041076
     2010-01-12    2.041076
     2010-01-13    2.720585
     2010-01-14    2.720585
     2010-01-15    3.656987
     Freq: D

>>> d_mva[10:20]
      2010-01-11    3.131125
      2010-01-12    3.035232
      2010-01-13    2.923144
      2010-01-14    2.811055
      2010-01-15    2.785824
      Freq: D

The function rolling_mean, along with about a dozen or so other function are informally grouped in the Pandas documentation under the rubric moving window functions; a second, related group of functions in Pandas is referred to as exponentially-weighted functions (e.g., ewma, which calculates exponentially moving weighted average). The fact that this second group is not included in the first (moving window functions) is perhaps because the exponentially-weighted transforms don't rely on a fixed-length window

Python: finding an element in a list

I found this by adapting some tutos. Thanks to google, and to all of you ;)

def findall(L, test):
    i=0
    indices = []
    while(True):
        try:
            # next value in list passing the test
            nextvalue = filter(test, L[i:])[0]

            # add index of this value in the index list,
            # by searching the value in L[i:] 
            indices.append(L.index(nextvalue, i))

            # iterate i, that is the next index from where to search
            i=indices[-1]+1
        #when there is no further "good value", filter returns [],
        # hence there is an out of range exeption
        except IndexError:
            return indices

A very simple use:

a = [0,0,2,1]
ind = findall(a, lambda x:x>0))

[2, 3]

P.S. scuse my english

Merge Two Lists in R

If lists always have the same structure, as in the example, then a simpler solution is

mapply(c, first, second, SIMPLIFY=FALSE)

Find object in list that has attribute equal to some value (that meets any condition)

A simple example: We have the following array

li = [{"id":1,"name":"ronaldo"},{"id":2,"name":"messi"}]

Now, we want to find the object in the array that has id equal to 1

  1. Use method next with list comprehension
next(x for x in li if x["id"] == 1 )
  1. Use list comprehension and return first item
[x for x in li if x["id"] == 1 ][0]
  1. Custom Function
def find(arr , id):
    for x in arr:
        if x["id"] == id:
            return x
find(li , 1)

Output all the above methods is {'id': 1, 'name': 'ronaldo'}

QED symbol in latex

Add to doc header:

\usepackage{ amssymb }

Then at the desired location add:

$ \blacksquare $

How to make <a href=""> link look like a button?

Like so many others, but with explanation in the css.

_x000D_
_x000D_
/* select all <a> elements with class "button" */
a.button {
  /* use inline-block because it respects padding */
  display: inline-block;
  /* padding creates clickable area around text (top/bottom, left/right) */
  padding: 1em 3em;
  /* round corners */
  border-radius: 5px;
  /* remove underline */
  text-decoration: none;
  /* set colors */
  color: white;
  background-color: #4E9CAF;
}
_x000D_
<a class="button" href="#">Add a problem</a>
_x000D_
_x000D_
_x000D_

Uncaught SyntaxError: Unexpected token with JSON.parse

I found the same issue with JSON.parse(inputString).

In my case the input string is coming from my server page [return of a page method].

I printed the typeof(inputString) - it was string, still the error occurs.

I also tried JSON.stringify(inputString), but it did not help.

Later I found this to be an issue with the new line operator [\n], inside a field value.

I did a replace [with some other character, put the new line back after parse] and everything is working fine.

javascript create array from for loop

You need to push i

var yearStart = 2000;
var yearEnd = 2040;

var arr = [];

for (var i = yearStart; i < yearEnd+1; i++) {
    arr.push(i);
}

Then, your resulting array will be:

arr = [2000, 2001, 2003, ... 2039, 2040]

Hope this helps

How to monitor SQL Server table changes by using c#?

This isn't exactly a notification but in the title you say monitor and this can fit that scenario.

Using the SQL Server timestamp column can allow you to easily see any changes (that still persist) between queries.

The SQL Server timestamp column type is badly named in my opinion as it is not related to time at all, it's a database wide value that auto increments on any insert or update. You can select Max(timestamp) in a table you are after or return the timestamp from the row you just inserted then just select where timestamp > storedTimestamp, this will give you all the results that have been updated or inserted between those times.

As it's a database wide value too you can use your stored timestamp to check any table has had data written to it since you last checked/updated your stored timestamp.

Connect to SQL Server through PDO using SQL Server Driver

try
{

    $conn = new PDO("sqlsrv:Server=$server_name;Database=$db_name;ConnectionPooling=0", "", "");
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

}
catch(PDOException $e)
{

    $e->getMessage();

}

Getting unique items from a list

Apart from the Distinct extension method of LINQ, you could use a HashSet<T> object that you initialise with your collection. This is most likely more efficient than the LINQ way, since it uses hash codes (GetHashCode) rather than an IEqualityComparer).

In fact, if it's appropiate for your situation, I would just use a HashSet for storing the items in the first place.

Creating a JSON array in C#

new {var_data[counter] =new [] { 
                new{  "S NO":  "+ obj_Data_Row["F_ID_ITEM_MASTER"].ToString() +","PART NAME": " + obj_Data_Row["F_PART_NAME"].ToString() + ","PART ID": " + obj_Data_Row["F_PART_ID"].ToString() + ","PART CODE":" + obj_Data_Row["F_PART_CODE"].ToString() + ", "CIENT PART ID": " + obj_Data_Row["F_ID_CLIENT"].ToString() + ","TYPES":" + obj_Data_Row["F_TYPE"].ToString() + ","UOM":" + obj_Data_Row["F_UOM"].ToString() + ","SPECIFICATION":" + obj_Data_Row["F_SPECIFICATION"].ToString() + ","MODEL":" + obj_Data_Row["F_MODEL"].ToString() + ","LOCATION":" + obj_Data_Row["F_LOCATION"].ToString() + ","STD WEIGHT":" + obj_Data_Row["F_STD_WEIGHT"].ToString() + ","THICKNESS":" + obj_Data_Row["F_THICKNESS"].ToString() + ","WIDTH":" + obj_Data_Row["F_WIDTH"].ToString() + ","HEIGHT":" + obj_Data_Row["F_HEIGHT"].ToString() + ","STUFF QUALITY":" + obj_Data_Row["F_STUFF_QTY"].ToString() + ","FREIGHT":" + obj_Data_Row["F_FREIGHT"].ToString() + ","THRESHOLD FG":" + obj_Data_Row["F_THRESHOLD_FG"].ToString() + ","THRESHOLD CL STOCK":" + obj_Data_Row["F_THRESHOLD_CL_STOCK"].ToString() + ","DESCRIPTION":" + obj_Data_Row["F_DESCRIPTION"].ToString() + "}
        }
    };

A more useful statusline in vim?

I currently use this statusbar settings:

set laststatus=2
set statusline=\ %f%m%r%h%w\ %=%({%{&ff}\|%{(&fenc==\"\"?&enc:&fenc).((exists(\"+bomb\")\ &&\ &bomb)?\",B\":\"\")}%k\|%Y}%)\ %([%l,%v][%p%%]\ %)

My complete .vimrc file: http://gabriev82.altervista.org/projects/vim-configuration/

Datetime format Issue: String was not recognized as a valid DateTime

You can use DateTime.ParseExact() method.

Converts the specified string representation of a date and time to its DateTime equivalent using the specified format and culture-specific format information. The format of the string representation must match the specified format exactly.

DateTime date = DateTime.ParseExact("04/30/2013 23:00", 
                                    "MM/dd/yyyy HH:mm", 
                                    CultureInfo.InvariantCulture);

Here is a DEMO.

hh is for 12-hour clock from 01 to 12, HH is for 24-hour clock from 00 to 23.

For more information, check Custom Date and Time Format Strings

Jquery array.push() not working

another workaround:

var myarray = [];
$("#test").click(function() {
    myarray[index]=$("#drop").val();
    alert(myarray);
});

i wanted to add all checked checkbox to array. so example, if .each is used:

var vpp = [];
var incr=0;
$('.prsn').each(function(idx) {
   if (this.checked) {
       var p=$('.pp').eq(idx).val();
       vpp[incr]=(p);
       incr++;
   }
});
//do what ever with vpp array;

How to check for an undefined or null variable in JavaScript?

I think the most efficient way to test for "value is null or undefined" is

if ( some_variable == null ){
  // some_variable is either null or undefined
}

So these two lines are equivalent:

if ( typeof(some_variable) !== "undefined" && some_variable !== null ) {}
if ( some_variable != null ) {}

Note 1

As mentioned in the question, the short variant requires that some_variable has been declared, otherwise a ReferenceError will be thrown. However in many use cases you can assume that this is safe:

check for optional arguments:

function(foo){
    if( foo == null ) {...}

check for properties on an existing object

if(my_obj.foo == null) {...}

On the other hand typeof can deal with undeclared global variables (simply returns undefined). Yet these cases should be reduced to a minimum for good reasons, as Alsciende explained.

Note 2

This - even shorter - variant is not equivalent:

if ( !some_variable ) {
  // some_variable is either null, undefined, 0, NaN, false, or an empty string
}

so

if ( some_variable ) {
  // we don't get here if some_variable is null, undefined, 0, NaN, false, or ""
}

Note 3

In general it is recommended to use === instead of ==. The proposed solution is an exception to this rule. The JSHint syntax checker even provides the eqnull option for this reason.

From the jQuery style guide:

Strict equality checks (===) should be used in favor of ==. The only exception is when checking for undefined and null by way of null.

// Check for both undefined and null values, for some important reason. 
undefOrNull == null;

How to instantiate a File object in JavaScript?

Update

BlobBuilder has been obsoleted see how you go using it, if you're using it for testing purposes.

Otherwise apply the below with migration strategies of going to Blob, such as the answers to this question.

Use a Blob instead

As an alternative there is a Blob that you can use in place of File as it is what File interface derives from as per W3C spec:

interface File : Blob {
    readonly attribute DOMString name;
    readonly attribute Date lastModifiedDate;
};

The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system.

Create the Blob

Using the BlobBuilder like this on an existing JavaScript method that takes a File to upload via XMLHttpRequest and supplying a Blob to it works fine like this:

var BlobBuilder = window.MozBlobBuilder || window.WebKitBlobBuilder;
var bb = new BlobBuilder();

var xhr = new XMLHttpRequest();
xhr.open('GET', 'http://jsfiddle.net/img/logo.png', true);

xhr.responseType = 'arraybuffer';

bb.append(this.response); // Note: not xhr.responseText

//at this point you have the equivalent of: new File()
var blob = bb.getBlob('image/png');

/* more setup code */
xhr.send(blob);

Extended example

The rest of the sample is up on jsFiddle in a more complete fashion but will not successfully upload as I can't expose the upload logic in a long term fashion.

How to share my Docker-Image without using the Docker-Hub?

Based on this blog, one could share a docker image without a docker registry by executing:

docker save --output latestversion-1.0.0.tar dockerregistry/latestversion:1.0.0

Once this command has been completed, one could copy the image to a server and import it as follows:

docker load --input latestversion-1.0.0.tar

Tomcat 7.0.43 "INFO: Error parsing HTTP request header"

I had this issue when working on a Java Project in Debian 10 with Tomcat as the application server.

The issue was that the application already had https defined as it's default protocol while I was using http to call the application in the browser. So when I try running the application I get this error in my log file:

org.apache.coyote.http11.AbstractHttp11Processor process
INFO: Error parsing HTTP request header
 Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level.

I however tried using the https protocol in the browser but it didn't connect throwing the error:

Here's how I solved it:

You need a certificate to setup the https protocol for the application. I first had to create a keystore file for the application, more like a self-signed certificate for the https protocol:

sudo keytool -genkey -keyalg RSA -alias tomcat -keystore /usr/share/tomcat.keystore

Note: You need to have Java installed on the server to be able to do this. Java can be installed using sudo apt install default-jdk.

Next, I added a https Tomcat server connector for the application in the Tomcat server configuration file (/opt/tomcat/conf/server.xml):

sudo nano /opt/tomcat/conf/server.xml

Add the following to the configuration of the application. Notice that the keystore file location and password are specified. Also a port for the https protocol is defined, which is different from the port for the http protocol:

<Connector protocol="org.apache.coyote.http11.Http11Protocol"
           port="8443" maxThreads="200" scheme="https"
           secure="true" SSLEnabled="true"
           keystoreFile="/usr/share/tomcat.keystore"
           keystorePass="my-password"
           clientAuth="false" sslProtocol="TLS"
           URIEncoding="UTF-8"
           compression="force"
           compressableMimeType="text/html,text/xml,text/plain,text/javascript,text/css"/>

So the full server configuration for the application looked liked this in the Tomcat server configuration file (/opt/tomcat/conf/server.xml):

<Service name="my-application">
  <Connector protocol="org.apache.coyote.http11.Http11Protocol"
             port="8443" maxThreads="200" scheme="https"
             secure="true" SSLEnabled="true"
             keystoreFile="/usr/share/tomcat.keystore"
             keystorePass="my-password"
             clientAuth="false" sslProtocol="TLS"
             URIEncoding="UTF-8"
             compression="force"
             compressableMimeType="text/html,text/xml,text/plain,text/javascript,text/css"/>

  <Connector port="8009" protocol="HTTP/1.1"
             connectionTimeout="20000"
             redirectPort="8443" />

  <Engine name="my-application" defaultHost="localhost">
     <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
             resourceName="UserDatabase"/>
    </Realm>

    <Host name="localhost"  appBase="webapps"
          unpackWARs="true" autoDeploy="true">

        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
             prefix="localhost_access_log" suffix=".txt"
             pattern="%h %l %u %t &quot;%r&quot; %s %b" />

    </Host>
  </Engine>
</Service>

This time when I tried accessing the application from the browser using:

https://my-server-ip-address:https-port

In my case it was:

https:35.123.45.6:8443

it worked fine. Although, I had to accept a warning which added a security exception for the website since the certificate used is a self-signed one.

That's all.

I hope this helps

Error:(23, 17) Failed to resolve: junit:junit:4.12

Go to Go to "File" -> "Project Structure" -> "App" In the tab "properties". In "Library Repository" field put 'http://repo1.maven.org/maven2' then press Ok. It was fixed like that for me. Now the project is compiling.

Optional Parameters in Go?

Another possibility would be to use a struct which with a field to indicate whether its valid. The null types from sql such as NullString are convenient. Its nice to not have to define your own type, but in case you need a custom data type you can always follow the same pattern. I think the optional-ness is clear from the function definition and there is minimal extra code or effort.

As an example:

func Foo(bar string, baz sql.NullString){
  if !baz.Valid {
        baz.String = "defaultValue"
  }
  // the rest of the implementation
}

How can I strip first and last double quotes?

Below function will strip the empty spces and return the strings without quotes. If there are no quotes then it will return same string(stripped)

def removeQuote(str):
str = str.strip()
if re.search("^[\'\"].*[\'\"]$",str):
    str = str[1:-1]
    print("Removed Quotes",str)
else:
    print("Same String",str)
return str

Change the color of cells in one column when they don't match cells in another column

you could try this:

I have these two columns (column "A" and column "B"). I want to color them when the values between cells in the same row mismatch.

Follow these steps:

  1. Select the elements in column "A" (excluding A1);

  2. Click on "Conditional formatting -> New Rule -> Use a formula to determine which cells to format";

  3. Insert the following formula: =IF(A2<>B2;1;0);

  4. Select the format options and click "OK";

  5. Select the elements in column "B" (excluding B1) and repeat the steps from 2 to 4.

How to view the committed files you have not pushed yet?

The previous answers are all good, but they all show origin/master. These days, following the best practices, I rarely work directly on a master branch, let alone from origin repo.

So if you are like me who work in a branch, here are tips:

  1. Say you are already on a branch. If not, git checkout that branch
  2. git log # to show a list of commit such as x08d46ffb1369e603c46ae96, You need only the latest commit which comes first.
  3. git show --name-only x08d46ffb1369e603c46ae96 # to show the files commited
  4. git show x08d46ffb1369e603c46ae96 # show the detail diff of each changed file

Or more simply, just use HEAD:

  1. git show --name-only HEAD # to show a list of files committed
  2. git show HEAD # to show the detail diff.

Transaction marked as rollback only: How do I find the cause

Look for exceptions being thrown and caught in the ... sections of your code. Runtime and rollbacking application exceptions cause rollback when thrown out of a business method even if caught on some other place.

You can use context to find out whether the transaction is marked for rollback.

@Resource
private SessionContext context;

context.getRollbackOnly();

How to get build time stamp from Jenkins build variables?

BUILD_ID used to provide this information but they changed it to provide the Build Number since Jenkins 1.597. Refer this for more information.

You can achieve this using the Build Time Stamp plugin as pointed out in the other answers.

However, if you are not allowed or not willing to use a plugin, follow the below method:

def BUILD_TIMESTAMP = null
withCredentials([usernamePassword(credentialsId: 'JenkinsCredentials', passwordVariable: 'JENKINS_PASSWORD', usernameVariable: 'JENKINS_USERNAME')]) {
   sh(script: "curl https://${JENKINS_USERNAME}:${JENKINS_PASSWORD}@<JENKINS_URL>/job/<JOB_NAME>/lastBuild/buildTimestamp", returnStdout: true).trim();
}
println BUILD_TIMESTAMP

This might seem a bit of overkill but manages to get the job done.

The credentials for accessing your Jenkins should be added and the id needs to be passed in the withCredentials statement, in place of 'JenkinsCredentials'. Feel free to omit that step if your Jenkins doesn't use authentication.

Pandas percentage of total with groupby

I think this needs benchmarking. Using OP's original DataFrame,

df = pd.DataFrame({
    'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
    'office_id': range(1, 7) * 2,
    'sales': [np.random.randint(100000, 999999) for _ in range(12)]
})

1st Andy Hayden

As commented on his answer, Andy takes full advantage of vectorisation and pandas indexing.

c = df.groupby(['state', 'office_id'])['sales'].sum().rename("count")
c / c.groupby(level=0).sum()

3.42 ms ± 16.7 µs per loop
(mean ± std. dev. of 7 runs, 100 loops each)


2nd Paul H

state_office = df.groupby(['state', 'office_id']).agg({'sales': 'sum'})
state = df.groupby(['state']).agg({'sales': 'sum'})
state_office.div(state, level='state') * 100

4.66 ms ± 24.4 µs per loop
(mean ± std. dev. of 7 runs, 100 loops each)


3rd exp1orer

This is the slowest answer as it calculates x.sum() for each x in level 0.

For me, this is still a useful answer, though not in its current form. For quick EDA on smaller datasets, apply allows you use method chaining to write this in a single line. We therefore remove the need decide on a variable's name, which is actually very computationally expensive for your most valuable resource (your brain!!).

Here is the modification,

(
    df.groupby(['state', 'office_id'])
    .agg({'sales': 'sum'})
    .groupby(level=0)
    .apply(lambda x: 100 * x / float(x.sum()))
)

10.6 ms ± 81.5 µs per loop
(mean ± std. dev. of 7 runs, 100 loops each)


So no one is going care about 6ms on a small dataset. However, this is 3x speed up and, on a larger dataset with high cardinality groupbys this is going to make a massive difference.

Adding to the above code, we make a DataFrame with shape (12,000,000, 3) with 14412 state categories and 600 office_ids,

import string

import numpy as np
import pandas as pd
np.random.seed(0)

groups = [
    ''.join(i) for i in zip(
    np.random.choice(np.array([i for i in string.ascii_lowercase]), 30000),
    np.random.choice(np.array([i for i in string.ascii_lowercase]), 30000),
    np.random.choice(np.array([i for i in string.ascii_lowercase]), 30000),
                       )
]

df = pd.DataFrame({'state': groups * 400,
               'office_id': list(range(1, 601)) * 20000,
               'sales': [np.random.randint(100000, 999999)
                         for _ in range(12)] * 1000000
})

Using Andy's,

2 s ± 10.4 ms per loop
(mean ± std. dev. of 7 runs, 1 loop each)

and exp1orer

19 s ± 77.1 ms per loop
(mean ± std. dev. of 7 runs, 1 loop each)

So now we see x10 speed up on large, high cardinality datasets.


Be sure to UV these three answers if you UV this one!!

Regarding C++ Include another class

you need to forward declare the name of the class if you don't want a header:

class ClassTwo;

Important: This only works in some cases, see Als's answer for more information..

Why es6 react component works only with "export default"?

Add { } while importing and exporting: export { ... }; | import { ... } from './Template';

exportimport { ... } from './Template'

export defaultimport ... from './Template'


Here is a working example:

// ExportExample.js
import React from "react";

function DefaultExport() {
  return "This is the default export";
}

function Export1() {
  return "Export without default 1";
}

function Export2() {
  return "Export without default 2";
}

export default DefaultExport;
export { Export1, Export2 };

// App.js
import React from "react";
import DefaultExport, { Export1, Export2 } from "./ExportExample";

export default function App() {
  return (
    <>
      <strong>
        <DefaultExport />
      </strong>
      <br />
      <Export1 />
      <br />
      <Export2 />
    </>
  );
}

??Working sandbox to play around: https://codesandbox.io/s/export-import-example-react-jl839?fontsize=14&hidenavigation=1&theme=dark

How can I get the count of line in a file in an efficient way?

All previous answers suggest to read though the whole file and count the amount of newlines you find while doing this. You commented some as "not effective" but thats the only way you can do that. A "line" is nothing else as a simple character inside the file. And to count that character you must have a look at every single character within the file.

I'm sorry, but you have no choice. :-)

How do I get the command-line for an Eclipse run configuration?

Scan your workspace .metadata directory for files called *.launch. I forget which plugin directory exactly holds these records, but it might even be the most basic org.eclipse.plugins.core one.

IF... OR IF... in a windows batch file

Thanks for this post, it helped me a lot.

Dunno if it can help but I had the issue and thanks to you I found what I think is another way to solve it based on this boolean equivalence:

"A or B" is the same as "not(not A and not B)"

Thus:

IF [%var%] == [1] OR IF [%var%] == [2] ECHO TRUE

Becomes:

IF not [%var%] == [1] IF not [%var%] == [2] ECHO FALSE

Difference between String replace() and replaceAll()

replace() method doesn't uses regex pattern whereas replaceAll() method uses regex pattern. So replace() performs faster than replaceAll().

Convert string in base64 to image and save on filesystem in Python

If you are trying to decode a web image you can simply use this :

import base64

with open("imageToSave.png", "wb") as fh:
  fh.write(base64.urlsafe_b64decode('data'))

data => is the encoded string

It will take care of the padding errors

env: node: No such file or directory in mac

NOTE: Only mac users!

  1. uninstall node completely with the commands
curl -ksO https://gist.githubusercontent.com/nicerobot/2697848/raw/uninstall-node.sh
chmod +x ./uninstall-node.sh
./uninstall-node.sh
rm uninstall-node.sh

Or you could check out this website: How do I completely uninstall Node.js, and reinstall from beginning (Mac OS X)

if this doesn't work, you need to remove node via control panel or any other method. As long as it gets removed.

  1. Install node via this website: https://nodejs.org/en/download/

If you use nvm, you can use:

nvm install node

You can already check if it works, then you don't need to take the following steps with: npm -v and then node -v

if you have nvm installed: command -v nvm

  1. Uninstall npm using the following command:

sudo npm uninstall npm -g

Or, if that fails, get the npm source code, and do:

sudo make uninstall

If you have nvm installed, then use: nvm uninstall npm

  1. Install npm using the following command: npm install -g grunt

How to fill Dataset with multiple tables?

DataSet ds = new DataSet();
using (var reader = cmd.ExecuteReader())
{
    while (!reader.IsClosed)
         {
              ds.Tables.Add().Load(reader);
         }
}
return ds;

ExecutorService that interrupts tasks after a timeout

Using John W answer I created an implementation that correctly begin the timeout when the task starts its execution. I even write a unit test for it :)

However, it does not suit my needs since some IO operations do not interrupt when Future.cancel() is called (ie when Thread.interrupt() is called). Some examples of IO operation that may not be interrupted when Thread.interrupt() is called are Socket.connect and Socket.read (and I suspect most of IO operation implemented in java.io). All IO operations in java.nio should be interruptible when Thread.interrupt() is called. For example, that is the case for SocketChannel.open and SocketChannel.read.

Anyway if anyone is interested, I created a gist for a thread pool executor that allows tasks to timeout (if they are using interruptible operations...): https://gist.github.com/amanteaux/64c54a913c1ae34ad7b86db109cbc0bf

Java Spring - How to use classpath to specify a file location?

Are we talking about standard java.io.FileReader? Won't work, but it's not hard without it.

/src/main/resources maven directory contents are placed in the root of your CLASSPATH, so you can simply retrieve it using:

InputStream is = getClass().getResourceAsStream("/storedProcedures.sql");

If the result is not null (resource not found), feel free to wrap it in a reader:

Reader reader = new InputStreamReader(is);

Dump all tables in CSV format using 'mysqldump'

You also can do it using Data Export tool in dbForge Studio for MySQL.

It will allow you to select some or all tables and export them into CSV format.

Const in JavaScript: when to use it and is it necessary?

'const' is an indication to your code that the identifier will not be reassigned. This is a good article about when to use 'const', 'let' or 'var' https://medium.com/javascript-scene/javascript-es6-var-let-or-const-ba58b8dcde75#.ukgxpfhao

How can I delete (not disable) ActiveX add-ons in Internet Explorer (7 and 8 Beta 2)?

Actually the "Remote" option in Configuration Menu for Plug-In works by me (Win7 64, ie8 with all updates), however:

  1. You need administrator rights
  2. The plug-in should be disabled before pressing the remove button
  3. You need restart internet-explorer to see the changes.

Also the previous comment about browsing-history->view objects was also useful if plug-in was installed right now.

Regards!

from unix timestamp to datetime

Note my use of t.format comes from using Moment.js, it is not part of JavaScript's standard Date prototype.

A Unix timestamp is the number of seconds since 1970-01-01 00:00:00 UTC.

The presence of the +0200 means the numeric string is not a Unix timestamp as it contains timezone adjustment information. You need to handle that separately.

If your timestamp string is in milliseconds, then you can use the milliseconds constructor and Moment.js to format the date into a string:

var t = new Date( 1370001284000 );
var formatted = t.format("dd.mm.yyyy hh:MM:ss");

If your timestamp string is in seconds, then use setSeconds:

var t = new Date();
t.setSeconds( 1370001284 );
var formatted = t.format("dd.mm.yyyy hh:MM:ss");

Detect click outside React component

Material-UI has a small component to solve this problem: https://material-ui.com/components/click-away-listener/ that you can cherry-pick it. It weights 1.5 kB gzipped, it supports mobile, IE 11 and portals.

Authentication issues with WWW-Authenticate: Negotiate

The web server is prompting you for a SPNEGO (Simple and Protected GSSAPI Negotiation Mechanism) token.

This is a Microsoft invention for negotiating a type of authentication to use for Web SSO (single-sign-on):

  • either NTLM
  • or Kerberos.

See:

How can I throw a general exception in Java?

The simplest way to do it would be something like:

throw new java.lang.Exception();

However, the following lines would be unreachable in your code. So, we have two ways:


  1. Throw a generic exception at the bottom of the method.
  2. Throw a custom exception in case you don't want to do 1.

Animate visibility modes, GONE and VISIBLE

You probably want to use an ExpandableListView, a special ListView that allows you to open and close groups.

How to hide action bar before activity is created, and then show it again?

you can use this :

getSupportActionBar().hide(); if it doesn't work try this one :

getActionBar().hide();

if above doesn't work try like this :

in your directory = res/values/style.xml , open style.xml -> there is attribute parent change to parent="Theme.AppCompat.Light.DarkActionBar"

if all of it doesn't work too. i don't know anymore. but for me it works.

Team Build Error: The Path ... is already mapped to workspace

TDN's solution worked for me when I was having the same issue. The Build server created workspaces under my account. Checking this box allowed me to see and delete them.

How to get UTC+0 date in Java 8?

tl;dr

Instant.now()

java.time

The troublesome old date-time classes bundled with the earliest versions of Java have been supplanted by the java.time classes built into Java 8 and later. See Oracle Tutorial. Much of the functionality has been back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP.

Instant

An Instant represents a moment on the timeline in UTC with a resolution of up to nanoseconds.

Instant instant = Instant.now();

The toString method generates a String object with text representing the date-time value using one of the standard ISO 8601 formats.

String output = instant.toString();  

2016-06-27T19:15:25.864Z

The Instant class is a basic building-block class in java.time. This should be your go-to class when handling date-time as generally the best practice is to track, store, and exchange date-time values in UTC.

OffsetDateTime

But Instant has limitations such as no formatting options for generating strings in alternate formats. For more flexibility, convert from Instant to OffsetDateTime. Specify an offset-from-UTC. In java.time that means a ZoneOffset object. Here we want to stick with UTC (+00) so we can use the convenient constant ZoneOffset.UTC.

OffsetDateTime odt = instant.atOffset( ZoneOffset.UTC );

2016-06-27T19:15:25.864Z

Or skip the Instant class.

OffsetDateTime.now( ZoneOffset.UTC )

Now with an OffsetDateTime object in hand, you can use DateTimeFormatter to create String objects with text in alternate formats. Search Stack Overflow for many examples of using DateTimeFormatter.

ZonedDateTime

When you want to display wall-clock time for some particular time zone, apply a ZoneId to get a ZonedDateTime.

In this example we apply Montréal time zone. In the summer, under Daylight Saving Time (DST) nonsense, the zone has an offset of -04:00. So note how the time-of-day is four hours earlier in the output, 15 instead of 19 hours. Instant and the ZonedDateTime both represent the very same simultaneous moment, just viewed through two different lenses.

ZoneId z = ZoneId.of( "America/Montreal" );
ZonedDateTime zdt = instant.atZone( z );

2016-06-27T15:15:25.864-04:00[America/Montreal]

Converting

While you should avoid the old date-time classes, if you must you can convert using new methods added to the old classes. Here we use java.util.Date.from( Instant ) and java.util.Date::toInstant.

java.util.Date utilDate = java.util.Date.from( instant );

And going the other direction.

Instant instant= utilDate.toInstant();

Similarly, look for new methods added to GregorianCalendar (subclass of Calendar) to convert to and from java.time.ZonedDateTime.

Table of types of date-time classes in modern java.time versus legacy.

About java.time

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

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

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

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes. Hibernate 5 & JPA 2.2 support java.time.

Where to obtain the java.time classes?

How to make an inline-block element fill the remainder of the line?

I've used flex-grow property to achieve this goal. You'll have to set display: flex for parent container, then you need to set flex-grow: 1 for the block you want to fill remaining space, or just flex: 1 as tanius mentioned in the comments.

What is a deadlock?

A deadlock is a state of a system in which no single process/thread is capable of executing an action. As mentioned by others, a deadlock is typically the result of a situation where each process/thread wishes to acquire a lock to a resource that is already locked by another (or even the same) process/thread.

There are various methods to find them and avoid them. One is thinking very hard and/or trying lots of things. However, dealing with parallelism is notoriously difficult and most (if not all) people will not be able to completely avoid problems.

Some more formal methods can be useful if you are serious about dealing with these kinds of issues. The most practical method that I'm aware of is to use the process theoretic approach. Here you model your system in some process language (e.g. CCS, CSP, ACP, mCRL2, LOTOS) and use the available tools to (model-)check for deadlocks (and perhaps some other properties as well). Examples of toolset to use are FDR, mCRL2, CADP and Uppaal. Some brave souls might even prove their systems deadlock free by using purely symbolic methods (theorem proving; look for Owicki-Gries).

However, these formal methods typically do require some effort (e.g. learning the basics of process theory). But I guess that's simply a consequence of the fact that these problems are hard.

What can be the reasons of connection refused errors?

Although it does not seem to be the case for your situation, sometimes a connection refused error can also indicate that there is an ip address conflict on your network. You can search for possible ip conflicts by running:

 arp-scan -I eth0 -l | grep <ipaddress>

and

arping <ipaddress>

This AskUbuntu question has some more information also.

Why XML-Serializable class need a parameterless constructor

First of all, this what is written in documentation. I think it is one of your class fields, not the main one - and how you want deserialiser to construct it back w/o parameterless construction ?

I think there is a workaround to make constructor private.

How to get a value from a cell of a dataframe?

For pandas 0.10, where iloc is unavalable, filter a DF and get the first row data for the column VALUE:

df_filt = df[df['C1'] == C1val & df['C2'] == C2val]
result = df_filt.get_value(df_filt.index[0],'VALUE')

if there is more then 1 row filtered, obtain the first row value. There will be an exception if the filter result in empty data frame.

Finding all objects that have a given property inside a collection

You can use something like JoSQL, and write 'SQL' against your collections: http://josql.sourceforge.net/

Which sounds like what you want, with the added benefit of being able to do more complicated queries.

Java finished with non-zero exit value 2 - Android Gradle

I didn't know (by then) that "compile fileTree(dir: 'libs', include: ['*.jar'])" compile all that has jar extension on libs folder, so i just comment (or delete) this lines:

//compile 'com.squareup.retrofit:retrofit:1.9.0'
//compile 'com.squareup.okhttp:okhttp-urlconnection:2.2.0'
//compile 'com.squareup.okhttp:okhttp:2.2.0'

//compile files('libs/spotify-web-api-android-master-0.1.0.jar')
//compile files('libs/okio-1.3.0.jar')

and it works fine. Thanks anyway! My bad.

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

You can write a simple helper function for it. Lodash has a similar function with the same name: omit

function omit(obj, omitKey) {
  return Object.keys(obj).reduce((result, key) => {
    if(key !== omitKey) {
       result[key] = obj[key];
    }
    return result;
  }, {});
}

omit({a: 1, b: 2, c: 3}, 'c')  // {a: 1, b: 2}

Also, note that it is faster than Object.assign and delete then: http://jsperf.com/omit-key

Saving binary data as file using JavaScript from a browser

To do this task download.js library can be used. Here is an example from library docs:

download("data:image/gif;base64,R0lGODlhRgAVAIcAAOfn5+/v7/f39////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////yH5BAAAAP8ALAAAAABGABUAAAj/AAEIHAgggMGDCAkSRMgwgEKBDRM+LBjRoEKDAjJq1GhxIMaNGzt6DAAypMORJTmeLKhxgMuXKiGSzPgSZsaVMwXUdBmTYsudKjHuBCoAIc2hMBnqRMqz6MGjTJ0KZcrz5EyqA276xJrVKlSkWqdGLQpxKVWyW8+iJcl1LVu1XttafTs2Lla3ZqNavAo37dm9X4eGFQtWKt+6T+8aDkxUqWKjeQUvfvw0MtHJcCtTJiwZsmLMiD9uplvY82jLNW9qzsy58WrWpDu/Lp0YNmPXrVMvRm3T6GneSX3bBt5VeOjDemfLFv1XOW7kncvKdZi7t/S7e2M3LkscLcvH3LF7HwSuVeZtjuPPe2d+GefPrD1RpnS6MGdJkebn4/+oMSAAOw==", "dlDataUrlBin.gif", "image/gif");

Upper memory limit?

You're reading the entire file into memory (line = u.readlines()) which will fail of course if the file is too large (and you say that some are up to 20 GB), so that's your problem right there.

Better iterate over each line:

for current_line in u:
    do_something_with(current_line)

is the recommended approach.

Later in your script, you're doing some very strange things like first counting all the items in a list, then constructing a for loop over the range of that count. Why not iterate over the list directly? What is the purpose of your script? I have the impression that this could be done much easier.

This is one of the advantages of high-level languages like Python (as opposed to C where you do have to do these housekeeping tasks yourself): Allow Python to handle iteration for you, and only collect in memory what you actually need to have in memory at any given time.

Also, as it seems that you're processing TSV files (tabulator-separated values), you should take a look at the csv module which will handle all the splitting, removing of \ns etc. for you.

PowerShell Connect to FTP server and get files

The AlexFTPS library used in the question seems to be dead (was not updated since 2011).


With no external libraries

You can try to implement this without any external library. But unfortunately, neither the .NET Framework nor PowerShell have any explicit support for downloading all files in a directory (let only recursive file downloads).

You have to implement that yourself:

  • List the remote directory
  • Iterate the entries, downloading files (and optionally recursing into subdirectories - listing them again, etc.)

Tricky part is to identify files from subdirectories. There's no way to do that in a portable way with the .NET framework (FtpWebRequest or WebClient). The .NET framework unfortunately does not support the MLSD command, which is the only portable way to retrieve directory listing with file attributes in FTP protocol. See also Checking if object on FTP server is file or directory.

Your options are:

  • If you know that the directory does not contain any subdirectories, use the ListDirectory method (NLST FTP command) and simply download all the "names" as files.
  • Do an operation on a file name that is certain to fail for file and succeeds for directories (or vice versa). I.e. you can try to download the "name".
  • You may be lucky and in your specific case, you can tell a file from a directory by a file name (i.e. all your files have an extension, while subdirectories do not)
  • You use a long directory listing (LIST command = ListDirectoryDetails method) and try to parse a server-specific listing. Many FTP servers use *nix-style listing, where you identify a directory by the d at the very beginning of the entry. But many servers use a different format. The following example uses this approach (assuming the *nix format)
function DownloadFtpDirectory($url, $credentials, $localPath)
{
    $listRequest = [Net.WebRequest]::Create($url)
    $listRequest.Method = [System.Net.WebRequestMethods+Ftp]::ListDirectoryDetails
    $listRequest.Credentials = $credentials

    $lines = New-Object System.Collections.ArrayList

    $listResponse = $listRequest.GetResponse()
    $listStream = $listResponse.GetResponseStream()
    $listReader = New-Object System.IO.StreamReader($listStream)
    while (!$listReader.EndOfStream)
    {
        $line = $listReader.ReadLine()
        $lines.Add($line) | Out-Null
    }
    $listReader.Dispose()
    $listStream.Dispose()
    $listResponse.Dispose()

    foreach ($line in $lines)
    {
        $tokens = $line.Split(" ", 9, [StringSplitOptions]::RemoveEmptyEntries)
        $name = $tokens[8]
        $permissions = $tokens[0]

        $localFilePath = Join-Path $localPath $name
        $fileUrl = ($url + $name)

        if ($permissions[0] -eq 'd')
        {
            if (!(Test-Path $localFilePath -PathType container))
            {
                Write-Host "Creating directory $localFilePath"
                New-Item $localFilePath -Type directory | Out-Null
            }

            DownloadFtpDirectory ($fileUrl + "/") $credentials $localFilePath
        }
        else
        {
            Write-Host "Downloading $fileUrl to $localFilePath"

            $downloadRequest = [Net.WebRequest]::Create($fileUrl)
            $downloadRequest.Method = [System.Net.WebRequestMethods+Ftp]::DownloadFile
            $downloadRequest.Credentials = $credentials

            $downloadResponse = $downloadRequest.GetResponse()
            $sourceStream = $downloadResponse.GetResponseStream()
            $targetStream = [System.IO.File]::Create($localFilePath)
            $buffer = New-Object byte[] 10240
            while (($read = $sourceStream.Read($buffer, 0, $buffer.Length)) -gt 0)
            {
                $targetStream.Write($buffer, 0, $read);
            }
            $targetStream.Dispose()
            $sourceStream.Dispose()
            $downloadResponse.Dispose()
        }
    }
}

Use the function like:

$credentials = New-Object System.Net.NetworkCredential("user", "mypassword") 
$url = "ftp://ftp.example.com/directory/to/download/"
DownloadFtpDirectory $url $credentials "C:\target\directory"

The code is translated from my C# example in C# Download all files and subdirectories through FTP.


Using 3rd party library

If you want to avoid troubles with parsing the server-specific directory listing formats, use a 3rd party library that supports the MLSD command and/or parsing various LIST listing formats. And ideally with a support for downloading all files from a directory or even recursive downloads.

For example with WinSCP .NET assembly you can download whole directory with a single call to Session.GetFiles:

# Load WinSCP .NET assembly
Add-Type -Path "WinSCPnet.dll"

# Setup session options
$sessionOptions = New-Object WinSCP.SessionOptions -Property @{
    Protocol = [WinSCP.Protocol]::Ftp
    HostName = "ftp.example.com"
    UserName = "user"
    Password = "mypassword"
}

$session = New-Object WinSCP.Session

try
{
    # Connect
    $session.Open($sessionOptions)

    # Download files
    $session.GetFiles("/directory/to/download/*", "C:\target\directory\*").Check()
}
finally
{
    # Disconnect, clean up
    $session.Dispose()
}    

Internally, WinSCP uses the MLSD command, if supported by the server. If not, it uses the LIST command and supports dozens of different listing formats.

The Session.GetFiles method is recursive by default.

(I'm the author of WinSCP)

How to add Python to Windows registry

When installing Python 3.4 the "Add python.exe to Path" came up unselected. Re-installed with this selected and problem resolved.

AWS EFS vs EBS vs S3 (differences & when to use?)

The main difference between EBS and EFS is that EBS is only accessible from a single EC2 instance in your particular AWS region, while EFS allows you to mount the file system across multiple regions and instances.

Finally, Amazon S3 is an object store good at storing vast numbers of backups or user files.

How to stop IIS asking authentication for default website on localhost

IIS uses Integrated Authentication and by default IE has the ability to use your windows user account...but don't worry, so does Firefox but you'll have to make a quick configuration change.

1) Open up Firefox and type in about:config as the url

2) In the Filter Type in ntlm

3) Double click "network.automatic-ntlm-auth.trusted-uris" and type in localhost and hit enter

4) Write Thank You To Blogger

As Always, Hope this helped you out.

This was copied from link text

How to get current available GPUs in tensorflow?

In TensorFlow 2.0, you can use tf.config.experimental.list_physical_devices('GPU'):

import tensorflow as tf
gpus = tf.config.experimental.list_physical_devices('GPU')
for gpu in gpus:
    print("Name:", gpu.name, "  Type:", gpu.device_type)

If you have two GPUs installed, it outputs this:

Name: /physical_device:GPU:0   Type: GPU
Name: /physical_device:GPU:1   Type: GPU

From 2.1, you can drop experimental:

gpus = tf.config.list_physical_devices('GPU')

See:

How to make ng-repeat filter out duplicate results

It seems everybody is throwing their own version of the unique filter into the ring, so I'll do the same. Critique is very welcome.

angular.module('myFilters', [])
  .filter('unique', function () {
    return function (items, attr) {
      var seen = {};
      return items.filter(function (item) {
        return (angular.isUndefined(attr) || !item.hasOwnProperty(attr))
          ? true
          : seen[item[attr]] = !seen[item[attr]];
      });
    };
  });

How to SELECT WHERE NOT EXIST using LINQ?

First of all, I suggest to modify a bit your sql query:

 select * from shift 
 where shift.shiftid not in (select employeeshift.shiftid from employeeshift 
                             where employeeshift.empid = 57);

This query provides same functionality. If you want to get the same result with LINQ, you can try this code:

//Variable dc has DataContext type here
//Here we get list of ShiftIDs from employeeshift table
List<int> empShiftIds = dc.employeeshift.Where(p => p.EmpID = 57).Select(s => s.ShiftID).ToList();

//Here we get the list of our shifts
List<shift> shifts = dc.shift.Where(p => !empShiftIds.Contains(p.ShiftId)).ToList();

How to make MySQL table primary key auto increment with some prefix

Here is PostgreSQL example without trigger if someone need it on PostgreSQL:

CREATE SEQUENCE messages_seq;

 CREATE TABLE IF NOT EXISTS messages (
    id CHAR(20) NOT NULL DEFAULT ('message_' || nextval('messages_seq')),
    name CHAR(30) NOT NULL,
);

ALTER SEQUENCE messages_seq OWNED BY messages.id;

Working with UTF-8 encoding in Python source

Do not forget to verify if your text editor encodes properly your code in UTF-8.

Otherwise, you may have invisible characters that are not interpreted as UTF-8.

How to copy files from host to Docker container?

tar and docker cp are a good combo for copying everything in a directory.

Create a data volume container

docker create --name dvc --volume /path/on/container cirros

To preserve the directory hierarchy

tar -c -C /path/on/local/machine . | docker cp - dvc:/path/on/container

Check your work

docker run --rm --volumes-from dvc cirros ls -al /path/on/container

Microsoft Visual C++ 14.0 is required (Unable to find vcvarsall.bat)

I had this exact issue while trying to install mayavi.

So I also had the common error: Microsoft Visual C++ 14.0 is required when pip installing a library.

Example of Error

After looking across many web pages and the solutions to this thread, with none of them working. I figured these steps (most taken from previous solutions) allowed this to work.

  1. Go to Build Tools for Visual Studio 2017 and install Build Tools for Visual Studio 2017. Which is under All downloads (scroll down) >> Tools for Visual Studio 2017
    • If you have already installed this skip to 2.

Installing Build Tools

  1. Select the C++ Components you require (I didn't know which I required so installed many of them).
    • If you have already installed Build Tools for Visual Studio 2017 then open the application Visual Studio Installer then go to Visual Studio Build Tools 2017 >> Modify >> Individual Components and selected the required components.
    • From other answers important components appear to be: C++/CLI support, VC++ 2017 version <...> latest, Visual C++ 2017 Redistributable Update, Visual C++ tools for CMake, Windows 10 SDK <...> for Desktop C++, Visual C++ Build Tools core features, Visual Studio C++ core features.

Select Components

  1. Install/Modify these components for Visual Studio Build Tools 2017.

  2. This is the important step. Open the application Visual Studio Installer then go to Visual Studio Build Tools >> Launch. Which will open a CMD window at the correct location for Microsoft Visual Studio\YYYY\BuildTools.

Open Visual Studio Installer Launch Visual Studio Build Tools CMD Build Tools Window

  1. Now enter python -m pip install --upgrade setuptools within this CMD window.

CMD Update Setuptools

  1. Finally, in this same CMD window pip install your python library: pip install -U <library>.

CMD Install Python Library

How to check if a variable is empty in python?

See section 5.1:

http://docs.python.org/library/stdtypes.html

Any object can be tested for truth value, for use in an if or while condition or as operand of the Boolean operations below. The following values are considered false:

None

False

zero of any numeric type, for example, 0, 0L, 0.0, 0j.

any empty sequence, for example, '', (), [].

any empty mapping, for example, {}.

instances of user-defined classes, if the class defines a __nonzero__() or __len__() method, when that method returns the integer zero or bool value False. [1]

All other values are considered true — so objects of many types are always true.

Operations and built-in functions that have a Boolean result always return 0 or False for false and 1 or True for true, unless otherwise stated. (Important exception: the Boolean operations or and and always return one of their operands.)

std::enable_if to conditionally compile a member function

From this post:

Default template arguments are not part of the signature of a template

But one can do something like this:

#include <iostream>

struct Foo {
    template < class T,
               class std::enable_if < !std::is_integral<T>::value, int >::type = 0 >
    void f(const T& value)
    {
        std::cout << "Not int" << std::endl;
    }

    template<class T,
             class std::enable_if<std::is_integral<T>::value, int>::type = 0>
    void f(const T& value)
    {
        std::cout << "Int" << std::endl;
    }
};

int main()
{
    Foo foo;
    foo.f(1);
    foo.f(1.1);

    // Output:
    // Int
    // Not int
}

Restore a deleted file in the Visual Studio Code Recycle Bin

Just look up the files you deleted, inside Recycle Bin. Right click on it and do restore as you do normally with other deleted files. It is similar as you do normally because VS code also uses normal trash of your system.

Conda command not found

If you have the PATH in your .bashrc file and are still getting

conda: command not found

Your terminal might not be looking for the bash file. Type bash in the terminal to insure you are in bash and then try: conda --version

How do I tell Spring Boot which main class to use for the executable jar?

If you're using spring-boot-starter-parent in your pom, you simply add the following to your pom:

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Then do your mvn package.

See this Spring docs page.

A very important aspect here is to mention that the directory structure has to be src/main/java/nameofyourpackage

ECONNREFUSED error when connecting to mongodb from node.js

I had facing the same issue while writing a simple rest api using node.js eventually found out it was due to wifi blockage and security reason . try once connecting it using your mobile hotspot . if this be the reason it will get resolved immediately.

Sorting Directory.GetFiles()

You could write a custom IComparer interface to sort by creation date, and then pass it to Array.Sort. You probably also want to look at StrCmpLogical, which is what is used to do the sorting Explorer uses (sorting numbers correctly with text).

CSS - Overflow: Scroll; - Always show vertical scroll bar?

Please note on iPad Safari, NoviceCoding's solution won't work if you have -webkit-overflow-scrolling: touch; somewhere in your CSS. The solution is either removing all the occurrences of -webkit-overflow-scrolling: touch; or putting -webkit-overflow-scrolling: auto; with NoviceCoding's solution.

Easiest way to convert a Blob into a byte array

the mySql blob class has the following function :

blob.getBytes

use it like this:

//(assuming you have a ResultSet named RS)
Blob blob = rs.getBlob("SomeDatabaseField");

int blobLength = (int) blob.length();  
byte[] blobAsBytes = blob.getBytes(1, blobLength);

//release the blob and free up memory. (since JDBC 4.0)
blob.free();

How to run python script on terminal (ubuntu)?

This error:

python: can't open file 'test.py': [Errno 2] No such file or directory

Means that the file "test.py" doesn't exist. (Or, it does, but it isn't in the current working directory.)

I must save the file in any specific folder to make it run on terminal?

No, it can be where ever you want. However, if you just say, "test.py", you'll need to be in the directory containing test.py.

Your terminal (actually, the shell in the terminal) has a concept of "Current working directory", which is what directory (folder) it is currently "in".

Thus, if you type something like:

python test.py

test.py needs to be in the current working directory. In Linux, you can change the current working directory with cd. You might want a tutorial if you're new. (Note that the first hit on that search for me is this YouTube video. The author in the video is using a Mac, but both Mac and Linux use bash for a shell, so it should apply to you.)

Deep copy in ES6 using the spread syntax

Here's my deep copy algorithm.

const DeepClone = (obj) => {
     if(obj===null||typeof(obj)!=='object')return null;
    let newObj = { ...obj };

    for (let prop in obj) {
      if (
        typeof obj[prop] === "object" ||
        typeof obj[prop] === "function"
      ) {
        newObj[prop] = DeepClone(obj[prop]);
      }
    }

    return newObj;
  };

Is there a simple JavaScript slider?

Here is a simple slider object for easy to use

pagecolumn_webparts_sliders

How to order results with findBy() in Doctrine

$ens = $em->getRepository('AcmeBinBundle:Marks')
              ->findBy(
                 array(), 
                 array('id' => 'ASC')
               );

Violation Long running JavaScript task took xx ms

I found a solution in Apache Cordova source code. They implement like this:

var resolvedPromise = typeof Promise == 'undefined' ? null : Promise.resolve();
var nextTick = resolvedPromise ? function(fn) { resolvedPromise.then(fn); } : function(fn) { setTimeout(fn); };

Simple implementation, but smart way.

Over the Android 4.4, use Promise. For older browsers, use setTimeout()


Usage:

nextTick(function() {
  // your code
});

After inserting this trick code, all warning messages are gone.

How to convert comma-separated String to List?

List<String> items = Arrays.asList(s.split("[,\\s]+"));

How to catch segmentation fault in Linux?

Sometimes we want to catch a SIGSEGV to find out if a pointer is valid, that is, if it references a valid memory address. (Or even check if some arbitrary value may be a pointer.)

One option is to check it with isValidPtr() (worked on Android):

int isValidPtr(const void*p, int len) {
    if (!p) {
    return 0;
    }
    int ret = 1;
    int nullfd = open("/dev/random", O_WRONLY);
    if (write(nullfd, p, len) < 0) {
    ret = 0;
    /* Not OK */
    }
    close(nullfd);
    return ret;
}
int isValidOrNullPtr(const void*p, int len) {
    return !p||isValidPtr(p, len);
}

Another option is to read the memory protection attributes, which is a bit more tricky (worked on Android):

re_mprot.c:

#include <errno.h>
#include <malloc.h>
//#define PAGE_SIZE 4096
#include "dlog.h"
#include "stdlib.h"
#include "re_mprot.h"

struct buffer {
    int pos;
    int size;
    char* mem;
};

char* _buf_reset(struct buffer*b) {
    b->mem[b->pos] = 0;
    b->pos = 0;
    return b->mem;
}

struct buffer* _new_buffer(int length) {
    struct buffer* res = malloc(sizeof(struct buffer)+length+4);
    res->pos = 0;
    res->size = length;
    res->mem = (void*)(res+1);
    return res;
}

int _buf_putchar(struct buffer*b, int c) {
    b->mem[b->pos++] = c;
    return b->pos >= b->size;
}

void show_mappings(void)
{
    DLOG("-----------------------------------------------\n");
    int a;
    FILE *f = fopen("/proc/self/maps", "r");
    struct buffer* b = _new_buffer(1024);
    while ((a = fgetc(f)) >= 0) {
    if (_buf_putchar(b,a) || a == '\n') {
        DLOG("/proc/self/maps: %s",_buf_reset(b));
    }
    }
    if (b->pos) {
    DLOG("/proc/self/maps: %s",_buf_reset(b));
    }
    free(b);
    fclose(f);
    DLOG("-----------------------------------------------\n");
}

unsigned int read_mprotection(void* addr) {
    int a;
    unsigned int res = MPROT_0;
    FILE *f = fopen("/proc/self/maps", "r");
    struct buffer* b = _new_buffer(1024);
    while ((a = fgetc(f)) >= 0) {
    if (_buf_putchar(b,a) || a == '\n') {
        char*end0 = (void*)0;
        unsigned long addr0 = strtoul(b->mem, &end0, 0x10);
        char*end1 = (void*)0;
        unsigned long addr1 = strtoul(end0+1, &end1, 0x10);
        if ((void*)addr0 < addr && addr < (void*)addr1) {
            res |= (end1+1)[0] == 'r' ? MPROT_R : 0;
            res |= (end1+1)[1] == 'w' ? MPROT_W : 0;
            res |= (end1+1)[2] == 'x' ? MPROT_X : 0;
            res |= (end1+1)[3] == 'p' ? MPROT_P
                 : (end1+1)[3] == 's' ? MPROT_S : 0;
            break;
        }
        _buf_reset(b);
    }
    }
    free(b);
    fclose(f);
    return res;
}

int has_mprotection(void* addr, unsigned int prot, unsigned int prot_mask) {
    unsigned prot1 = read_mprotection(addr);
    return (prot1 & prot_mask) == prot;
}

char* _mprot_tostring_(char*buf, unsigned int prot) {
    buf[0] = prot & MPROT_R ? 'r' : '-';
    buf[1] = prot & MPROT_W ? 'w' : '-';
    buf[2] = prot & MPROT_X ? 'x' : '-';
    buf[3] = prot & MPROT_S ? 's' : prot & MPROT_P ? 'p' :  '-';
    buf[4] = 0;
    return buf;
}

re_mprot.h:

#include <alloca.h>
#include "re_bits.h"
#include <sys/mman.h>

void show_mappings(void);

enum {
    MPROT_0 = 0, // not found at all
    MPROT_R = PROT_READ,                                 // readable
    MPROT_W = PROT_WRITE,                                // writable
    MPROT_X = PROT_EXEC,                                 // executable
    MPROT_S = FIRST_UNUSED_BIT(MPROT_R|MPROT_W|MPROT_X), // shared
    MPROT_P = MPROT_S<<1,                                // private
};

// returns a non-zero value if the address is mapped (because either MPROT_P or MPROT_S will be set for valid addresses)
unsigned int read_mprotection(void* addr);

// check memory protection against the mask
// returns true if all bits corresponding to non-zero bits in the mask
// are the same in prot and read_mprotection(addr)
int has_mprotection(void* addr, unsigned int prot, unsigned int prot_mask);

// convert the protection mask into a string. Uses alloca(), no need to free() the memory!
#define mprot_tostring(x) ( _mprot_tostring_( (char*)alloca(8) , (x) ) )
char* _mprot_tostring_(char*buf, unsigned int prot);

PS DLOG() is printf() to the Android log. FIRST_UNUSED_BIT() is defined here.

PPS It may not be a good idea to call alloca() in a loop -- the memory may be not freed until the function returns.

How do I print the elements of a C++ vector in GDB?

A little late to the party, so mostly a reminder to me next time I do this search!

I have been able to use:

p/x *(&vec[2])@4

to print 4 elements (as hex) from vec starting at vec[2].

How to resize images proportionally / keeping the aspect ratio?

This issue can be solved by CSS.

.image{
 max-width:*px;
}

Get the length of a String

In Swift 4.2 and Xcode 10.1

In Swift strings can be treated like an array of individual characters. So each character in string is like an element in array. To get the length of a string use yourStringName.count property.

In Swift

yourStringName.characters.count property in deprecated. So directly use strLength.count property.

let strLength = "This is my string"
print(strLength.count)
//print(strLength.characters.count) //Error: 'characters' is deprecated: Please use String or Substring directly

If Objective C

NSString *myString = @"Hello World";
NSLog(@"%lu", [myString length]); // 11

Cleanest way to build an SQL string in Java

I have been working on a Java servlet application that needs to construct very dynamic SQL statements for adhoc reporting purposes. The basic function of the app is to feed a bunch of named HTTP request parameters into a pre-coded query, and generate a nicely formatted table of output. I used Spring MVC and the dependency injection framework to store all of my SQL queries in XML files and load them into the reporting application, along with the table formatting information. Eventually, the reporting requirements became more complicated than the capabilities of the existing parameter mapping frameworks and I had to write my own. It was an interesting exercise in development and produced a framework for parameter mapping much more robust than anything else I could find.

The new parameter mappings looked as such:

select app.name as "App", 
       ${optional(" app.owner as "Owner", "):showOwner}
       sv.name as "Server", sum(act.trans_ct) as "Trans"
  from activity_records act, servers sv, applications app
 where act.server_id = sv.id
   and act.app_id = app.id
   and sv.id = ${integer(0,50):serverId}
   and app.id in ${integerList(50):appId}
 group by app.name, ${optional(" app.owner, "):showOwner} sv.name
 order by app.name, sv.name

The beauty of the resulting framework was that it could process HTTP request parameters directly into the query with proper type checking and limit checking. No extra mappings required for input validation. In the example query above, the parameter named serverId would be checked to make sure it could cast to an integer and was in the range of 0-50. The parameter appId would be processed as an array of integers, with a length limit of 50. If the field showOwner is present and set to "true", the bits of SQL in the quotes will be added to the generated query for the optional field mappings. field Several more parameter type mappings are available including optional segments of SQL with further parameter mappings. It allows for as complex of a query mapping as the developer can come up with. It even has controls in the report configuration to determine whether a given query will have the final mappings via a PreparedStatement or simply ran as a pre-built query.

For the sample Http request values:

showOwner: true
serverId: 20
appId: 1,2,3,5,7,11,13

It would produce the following SQL:

select app.name as "App", 
       app.owner as "Owner", 
       sv.name as "Server", sum(act.trans_ct) as "Trans"
  from activity_records act, servers sv, applications app
 where act.server_id = sv.id
   and act.app_id = app.id
   and sv.id = 20
   and app.id in (1,2,3,5,7,11,13)
 group by app.name,  app.owner,  sv.name
 order by app.name, sv.name

I really think that Spring or Hibernate or one of those frameworks should offer a more robust mapping mechanism that verifies types, allows for complex data types like arrays and other such features. I wrote my engine for only my purposes, it isn't quite read for general release. It only works with Oracle queries at the moment and all of the code belongs to a big corporation. Someday I may take my ideas and build a new open source framework, but I'm hoping one of the existing big players will take up the challenge.

Error occurred during initialization of VM Could not reserve enough space for object heap Could not create the Java virtual machine

I've just seen this problem myself, Jboss AS7 with jdk1.5.0_09. Update System Property JAVA_HOME to jdk1.7+ to fix (I'm using jdk1.7.0_67).

How can I check if a Perl array contains a particular value?

You certainly want a hash here. Place the bad parameters as keys in the hash, then decide whether a particular parameter exists in the hash.

our %bad_params = map { $_ => 1 } qw(badparam1 badparam2 badparam3)

if ($bad_params{$new_param}) {
  print "That is a bad parameter\n";
}

If you are really interested in doing it with an array, look at List::Util or List::MoreUtils

How can I run Android emulator for Intel x86 Atom without hardware acceleration on Windows 8 for API 21 and 19?

Is there any way that I can start android emulator for intel x86 atom Without hardware acceleration on windows 8

Not with the standard Android SDK emulator, as it requires Intel's HAXM, and HAXM wants virtualization extensions to be enabled.

Whether Genymotion or something else from another independent developer can support your desired combination, I cannot say.

Get value from a string after a special character

_x000D_
_x000D_
//var val = $("#FieldId").val()_x000D_
//Get Value of hidden field by val() jquery function I'm using example string._x000D_
var val = "String to find after - DEMO"_x000D_
var foundString = val.substr(val.indexOf(' - ')+3,)_x000D_
console.log(foundString);
_x000D_
_x000D_
_x000D_ Assuming you need to find DEMO string after - by above code you can able to access DEMO string substr will return the string from whaterver the value indexOf return till the end of string it will return everything.

EXCEL Multiple Ranges - need different answers for each range

use

=VLOOKUP(D4,F4:G9,2)

with the range F4:G9:

0   0.1
1   0.15
5   0.2
15  0.3
30  1
100 1.3

and D4 being the value in question, e.g. 18.75 -> result: 0.3

What is a method group in C#?

The ToString function has many overloads - the method group would be the group consisting of all the different overloads for that function.

Sending Multipart File as POST parameters with RestTemplate requests

I recently struggled with this issue for 3 days. How the client is sending the request might not be the cause, the server might not be configured to handle multipart requests. This is what I had to do to get it working:

pom.xml - Added commons-fileupload dependency (download and add the jar to your project if you are not using dependency management such as maven)

<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>${commons-version}</version>
</dependency>

web.xml - Add multipart filter and mapping

<filter>
  <filter-name>multipartFilter</filter-name>
  <filter-class>org.springframework.web.multipart.support.MultipartFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>multipartFilter</filter-name>
  <url-pattern>/springrest/*</url-pattern>
</filter-mapping>

app-context.xml - Add multipart resolver

<beans:bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <beans:property name="maxUploadSize">
        <beans:value>10000000</beans:value>
    </beans:property>
</beans:bean>

Your Controller

@RequestMapping(value=Constants.REQUEST_MAPPING_ADD_IMAGE, method = RequestMethod.POST, produces = { "application/json"})
public @ResponseBody boolean saveStationImage(
        @RequestParam(value = Constants.MONGO_STATION_PROFILE_IMAGE_FILE) MultipartFile file,
        @RequestParam(value = Constants.MONGO_STATION_PROFILE_IMAGE_URI) String imageUri, 
        @RequestParam(value = Constants.MONGO_STATION_PROFILE_IMAGE_TYPE) String imageType, 
        @RequestParam(value = Constants.MONGO_FIELD_STATION_ID) String stationId) {
    // Do something with file
    // Return results
}

Your client

public static Boolean updateStationImage(StationImage stationImage) {
    if(stationImage == null) {
        Log.w(TAG + ":updateStationImage", "Station Image object is null, returning.");
        return null;
    }

    Log.d(TAG, "Uploading: " + stationImage.getImageUri());
    try {
        RestTemplate restTemplate = new RestTemplate();
        FormHttpMessageConverter formConverter = new FormHttpMessageConverter();
        formConverter.setCharset(Charset.forName("UTF8"));
        restTemplate.getMessageConverters().add(formConverter);
        restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());

        restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory());

        HttpHeaders httpHeaders = new HttpHeaders();
        httpHeaders.setAccept(Collections.singletonList(MediaType.parseMediaType("application/json")));

        MultiValueMap<String, Object> parts = new LinkedMultiValueMap<String, Object>();

        parts.add(Constants.STATION_PROFILE_IMAGE_FILE, new FileSystemResource(stationImage.getImageFile()));
        parts.add(Constants.STATION_PROFILE_IMAGE_URI, stationImage.getImageUri());
        parts.add(Constants.STATION_PROFILE_IMAGE_TYPE, stationImage.getImageType());
        parts.add(Constants.FIELD_STATION_ID, stationImage.getStationId());

        return restTemplate.postForObject(Constants.REST_CLIENT_URL_ADD_IMAGE, parts, Boolean.class);
    } catch (Exception e) {
        StringWriter sw = new StringWriter();
        e.printStackTrace(new PrintWriter(sw));

        Log.e(TAG + ":addStationImage", sw.toString());
    }

    return false;
}

That should do the trick. I added as much information as possible because I spent days, piecing together bits and pieces of the full issue, I hope this will help.

Difference between Java SE/EE/ME?

Java SE is use for the desktop applications and simple core functions. Java EE is used for desktop, but also web development, networking, and advanced things.

How to remove RVM (Ruby Version Manager) from my system

When using implode and you see:

Psychologist intervened, cancelling implosion, crisis avoided :)

Then you may want to use --force

rvm implode --force

Then remove RVM from the following locations:

rm -rf /usr/local/rvm
sudo rm /etc/profile.d/rvm.sh
sudo rm /etc/rvmrc
sudo rm ~/.rvmrc

Check the following files and remove or comment out references to RVM:

~/.bashrc 
~/.bash_profile 
~/.profile 
~/.zshrc
~/.zlogin

Comment-out/remove the following lines from /etc/profile:

 source /etc/profile.d/sm.sh
 source /etc/profile.d/rvm.sh

/etc/profile is a read-only file so use:

sudo vim /etc/profile

And after making the change write using a bang!

:w!

Finally re-login/restart your terminal.

Android TextView padding between lines

You can use lineSpacingExtra and lineSpacingMultiplier in your XML file.

Responsive background image in div full width

I also tried this style for ionic hybrid app background. this is also having style for background blur effect.

.bg-image {
   position: absolute;
   background: url(../img/bglogin.jpg) no-repeat;
   height: 100%;
   width: 100%;
   background-size: cover;
   bottom: 0px;
   margin: 0 auto;
   background-position: 50%;


  -webkit-filter: blur(5px);
  -moz-filter: blur(5px);
  -o-filter: blur(5px);
  -ms-filter: blur(5px);
  filter: blur(5px);

}

Default value of function parameter

If you put the declaration in a header file, and the definition in a separate .cpp file, and #include the header from a different .cpp file, you will be able to see the difference.

Specifically, suppose:

lib.h

int Add(int a, int b);

lib.cpp

int Add(int a, int b = 3) {
   ...
}

test.cpp

#include "lib.h"

int main() {
    Add(4);
}

The compilation of test.cpp will not see the default parameter declaration, and will fail with an error.

For this reason, the default parameter definition is usually specified in the function declaration:

lib.h

int Add(int a, int b = 3);

conditional Updating a list using LINQ

You need:

li.Where(w=> w.name == "di").ToList().ForEach(i => i.age = 10);

Program code:

namespace Test
{
    class Program
    {
        class Myclass
        {
            public string name { get; set; }
            public decimal age { get; set; }
        }

        static void Main(string[] args)
        {
            var list = new List<Myclass> { new Myclass{name = "di", age = 0}, new Myclass{name = "marks", age = 0}, new Myclass{name = "grade", age = 0}};
            list.Where(w=> w.name == "di").ToList().ForEach(i => i.age = 10);
            list.ForEach(i => Console.WriteLine(i.name + ":" + i.age));
        }
    }
}

Output:

 di:10
 marks:0
 grade:0

how to check which version of nltk, scikit learn installed?

For checking the version of scikit-learn in shell script, if you have pip installed, you can try this command

pip freeze | grep scikit-learn
scikit-learn==0.17.1

Hope it helps!

Node.js quick file server (static files over HTTP)

First install node-static server via npm install node-static -g -g is to install it global on your system, then navigate to the directory where your files are located, start the server with static it listens on port 8080, naviaget to the browser and type localhost:8080/yourhtmlfilename.

Deleting all pending tasks in celery / rabbitmq

For celery 3.0+:

$ celery purge

To purge a specific queue:

$ celery -Q queue_name purge

sql server convert date to string MM/DD/YYYY

select convert(varchar(10), fmdate, 101) from sery

101 is a style argument.

Rest of 'em can be found here.

T-SQL Cast / Convert date to string

Get PHP class property by string

What you're asking about is called Variable Variables. All you need to do is store your string in a variable and access it like so:

$Class = 'MyCustomClass';
$Property = 'Name';
$List = array('Name');

$Object = new $Class();

// All of these will echo the same property
echo $Object->$Property;  // Evaluates to $Object->Name
echo $Object->{$List[0]}; // Use if your variable is in an array

How to insert a row in an HTML table body in JavaScript

If you want to add a row into the tbody, get a reference to it and call its insertRow method.

_x000D_
_x000D_
var tbodyRef = document.getElementById('myTable').getElementsByTagName('tbody')[0];

// Insert a row at the end of table
var newRow = tbodyRef.insertRow();

// Insert a cell at the end of the row
var newCell = newRow.insertCell();

// Append a text node to the cell
var newText = document.createTextNode('new row');
newCell.appendChild(newText);
_x000D_
<table id="myTable">
  <thead>
    <tr>
      <th>My Header</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>initial row</td>
    </tr>
  </tbody>
  <tfoot>
    <tr>
      <td>My Footer</td>
    </tr>
  </tfoot>
</table>
_x000D_
_x000D_
_x000D_

(old demo on JSFiddle)

How to read strings from a Scanner in a Java console application?

What you can do is use delimeter as new line. Till you press enter key you will be able to read it as string.

Scanner sc = new Scanner(System.in);
sc.useDelimiter(System.getProperty("line.separator"));

Hope this helps.

Change type of varchar field to integer: "cannot be cast automatically to type integer"

this worked for me.

change varchar column to int

change_column :table_name, :column_name, :integer

got:

PG::DatatypeMismatch: ERROR:  column "column_name" cannot be cast automatically to type integer
HINT:  Specify a USING expression to perform the conversion.

chnged to

change_column :table_name, :column_name, 'integer USING CAST(column_name AS integer)'

Understanding [TCP ACKed unseen segment] [TCP Previous segment not captured]

That very well may be a false positive. Like the warning message says, it is common for a capture to start in the middle of a tcp session. In those cases it does not have that information. If you are really missing acks then it is time to start looking upstream from your host for where they are disappearing. It is possible that tshark can not keep up with the data and so it is dropping some metrics. At the end of your capture it will tell you if the "kernel dropped packet" and how many. By default tshark disables dns lookup, tcpdump does not. If you use tcpdump you need to pass in the "-n" switch. If you are having a disk IO issue then you can do something like write to memory /dev/shm. BUT be careful because if your captures get very large then you can cause your machine to start swapping.

My bet is that you have some very long running tcp sessions and when you start your capture you are simply missing some parts of the tcp session due to that. Having said that, here are some of the things that I have seen cause duplicate/missing acks.

  1. Switches - (very unlikely but sometimes they get in a sick state)
  2. Routers - more likely than switches, but not much
  3. Firewall - More likely than routers. Things to look for here are resource exhaustion (license, cpu, etc)
  4. Client side filtering software - antivirus, malware detection etc.

MYSQL Truncated incorrect DOUBLE value

It seems mysql handles the type casting gracefully with SELECT statements. The shop_id field is of type varchar but the select statements works

select * from shops where shop_id = 26244317283;

But when you try updating the fields

update stores set store_url = 'https://test-url.com' where shop_id = 26244317283;

It fails with error Truncated incorrect DOUBLE value: '1t5hxq9'

You need to put the shop_id 26244317283 in quotes '26244317283' for the query to work since the field is of type varchar not int

update stores set store_url = 'https://test-url.com' where shop_id = '26244317283';

How can I display a modal dialog in Redux that performs asynchronous actions?

Update: React 16.0 introduced portals through ReactDOM.createPortal link

Update: next versions of React (Fiber: probably 16 or 17) will include a method to create portals: ReactDOM.unstable_createPortal() link


Use portals

Dan Abramov answer first part is fine, but involves a lot of boilerplate. As he said, you can also use portals. I'll expand a bit on that idea.

The advantage of a portal is that the popup and the button remain very close into the React tree, with very simple parent/child communication using props: you can easily handle async actions with portals, or let the parent customize the portal.

What is a portal?

A portal permits you to render directly inside document.body an element that is deeply nested in your React tree.

The idea is that for example you render into body the following React tree:

<div className="layout">
  <div className="outside-portal">
    <Portal>
      <div className="inside-portal">
        PortalContent
      </div>
    </Portal>
  </div>
</div>

And you get as output:

<body>
  <div class="layout">
    <div class="outside-portal">
    </div>
  </div>
  <div class="inside-portal">
    PortalContent
  </div>
</body>

The inside-portal node has been translated inside <body>, instead of its normal, deeply-nested place.

When to use a portal

A portal is particularly helpful for displaying elements that should go on top of your existing React components: popups, dropdowns, suggestions, hotspots

Why use a portal

No z-index problems anymore: a portal permits you to render to <body>. If you want to display a popup or dropdown, this is a really nice idea if you don't want to have to fight against z-index problems. The portal elements get added do document.body in mount order, which means that unless you play with z-index, the default behavior will be to stack portals on top of each others, in mounting order. In practice, it means that you can safely open a popup from inside another popup, and be sure that the 2nd popup will be displayed on top of the first, without having to even think about z-index.

In practice

Most simple: use local React state: if you think, for a simple delete confirmation popup, it's not worth to have the Redux boilerplate, then you can use a portal and it greatly simplifies your code. For such a use case, where the interaction is very local and is actually quite an implementation detail, do you really care about hot-reloading, time-traveling, action logging and all the benefits Redux brings you? Personally, I don't and use local state in this case. The code becomes as simple as:

class DeleteButton extends React.Component {
  static propTypes = {
    onDelete: PropTypes.func.isRequired,
  };

  state = { confirmationPopup: false };

  open = () => {
    this.setState({ confirmationPopup: true });
  };

  close = () => {
    this.setState({ confirmationPopup: false });
  };

  render() {
    return (
      <div className="delete-button">
        <div onClick={() => this.open()}>Delete</div>
        {this.state.confirmationPopup && (
          <Portal>
            <DeleteConfirmationPopup
              onCancel={() => this.close()}
              onConfirm={() => {
                this.close();
                this.props.onDelete();
              }}
            />
          </Portal>
        )}
      </div>
    );
  }
}

Simple: you can still use Redux state: if you really want to, you can still use connect to choose whether or not the DeleteConfirmationPopup is shown or not. As the portal remains deeply nested in your React tree, it is very simple to customize the behavior of this portal because your parent can pass props to the portal. If you don't use portals, you usually have to render your popups at the top of your React tree for z-index reasons, and usually have to think about things like "how do I customize the generic DeleteConfirmationPopup I built according to the use case". And usually you'll find quite hacky solutions to this problem, like dispatching an action that contains nested confirm/cancel actions, a translation bundle key, or even worse, a render function (or something else unserializable). You don't have to do that with portals, and can just pass regular props, since DeleteConfirmationPopup is just a child of the DeleteButton

Conclusion

Portals are very useful to simplify your code. I couldn't do without them anymore.

Note that portal implementations can also help you with other useful features like:

  • Accessibility
  • Espace shortcuts to close the portal
  • Handle outside click (close portal or not)
  • Handle link click (close portal or not)
  • React Context made available in portal tree

react-portal or react-modal are nice for popups, modals, and overlays that should be full-screen, generally centered in the middle of the screen.

react-tether is unknown to most React developers, yet it's one of the most useful tools you can find out there. Tether permits you to create portals, but will position automatically the portal, relative to a given target. This is perfect for tooltips, dropdowns, hotspots, helpboxes... If you have ever had any problem with position absolute/relative and z-index, or your dropdown going outside of your viewport, Tether will solve all that for you.

You can, for example, easily implement onboarding hotspots, that expands to a tooltip once clicked:

Onboarding hotspot

Real production code here. Can't be any simpler :)

<MenuHotspots.contacts>
  <ContactButton/>
</MenuHotspots.contacts>

Edit: just discovered react-gateway which permits to render portals into the node of your choice (not necessarily body)

Edit: it seems react-popper can be a decent alternative to react-tether. PopperJS is a library that only computes an appropriate position for an element, without touching the DOM directly, letting the user choose where and when he wants to put the DOM node, while Tether appends directly to the body.

Edit: there's also react-slot-fill which is interesting and can help solve similar problems by allowing to render an element to a reserved element slot that you put anywhere you want in your tree

Django URL Redirect

The other methods work fine, but you can also use the good old django.shortcut.redirect.

The code below was taken from this answer.

In Django 2.x:

from django.shortcuts import redirect
from django.urls import path, include

urlpatterns = [
    # this example uses named URL 'hola-home' from app named hola
    # for more redirect's usage options: https://docs.djangoproject.com/en/2.1/topics/http/shortcuts/
    path('', lambda request: redirect('hola/', permanent=True)),
    path('hola/', include('hola.urls')),
]

Spark SQL: apply aggregate functions to a list of columns

Another example of the same concept - but say - you have 2 different columns - and you want to apply different agg functions to each of them i.e

f.groupBy("col1").agg(sum("col2").alias("col2"), avg("col3").alias("col3"), ...)

Here is the way to achieve it - though I do not yet know how to add the alias in this case

See the example below - Using Maps

val Claim1 = StructType(Seq(StructField("pid", StringType, true),StructField("diag1", StringType, true),StructField("diag2", StringType, true), StructField("allowed", IntegerType, true), StructField("allowed1", IntegerType, true)))
val claimsData1 = Seq(("PID1", "diag1", "diag2", 100, 200), ("PID1", "diag2", "diag3", 300, 600), ("PID1", "diag1", "diag5", 340, 680), ("PID2", "diag3", "diag4", 245, 490), ("PID2", "diag2", "diag1", 124, 248))

val claimRDD1 = sc.parallelize(claimsData1)
val claimRDDRow1 = claimRDD1.map(p => Row(p._1, p._2, p._3, p._4, p._5))
val claimRDD2DF1 = sqlContext.createDataFrame(claimRDDRow1, Claim1)

val l = List("allowed", "allowed1")
val exprs = l.map((_ -> "sum")).toMap
claimRDD2DF1.groupBy("pid").agg(exprs) show false
val exprs = Map("allowed" -> "sum", "allowed1" -> "avg")

claimRDD2DF1.groupBy("pid").agg(exprs) show false

How to define object in array in Mongoose schema correctly with 2d geo index

You can declare trk by the following ways : - either

trk : [{
    lat : String,
    lng : String
     }]

or

trk : { type : Array , "default" : [] }

In the second case during insertion make the object and push it into the array like

db.update({'Searching criteria goes here'},
{
 $push : {
    trk :  {
             "lat": 50.3293714,
             "lng": 6.9389939
           } //inserted data is the object to be inserted 
  }
});

or you can set the Array of object by

db.update ({'seraching criteria goes here ' },
{
 $set : {
          trk : [ {
                     "lat": 50.3293714,
                     "lng": 6.9389939
                  },
                  {
                     "lat": 50.3293284,
                     "lng": 6.9389634
                  }
               ]//'inserted Array containing the list of object'
      }
});

How to get Chrome to allow mixed content?

"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" " --allow-running-insecure-content"

How do I delete multiple rows in Entity Framework (without foreach)

You can use extensions libraries for doing that like EntityFramework.Extended or Z.EntityFramework.Plus.EF6, there are available for EF 5, 6 or Core. These libraries have great performance when you have to delete or update and they use LINQ. Example for deleting (source plus):

ctx.Users.Where(x => x.LastLoginDate < DateTime.Now.AddYears(-2)) .Delete();

or (source extended)

context.Users.Where(u => u.FirstName == "firstname") .Delete();

These use native SQL statements, so performance is great.

Convert from ASCII string encoded in Hex to plain ASCII?

>>> txt = '7061756c'
>>> ''.join([chr(int(''.join(c), 16)) for c in zip(txt[0::2],txt[1::2])])
'paul'                                                                          

i'm just having fun, but the important parts are:

>>> int('0a',16)         # parse hex
10
>>> ''.join(['a', 'b'])  # join characters
'ab'
>>> 'abcd'[0::2]         # alternates
'ac'
>>> zip('abc', '123')    # pair up
[('a', '1'), ('b', '2'), ('c', '3')]        
>>> chr(32)              # ascii to character
' '

will look at binascii now...

>>> print binascii.unhexlify('7061756c')
paul

cool (and i have no idea why other people want to make you jump through hoops before they'll help).

How to use PHP to connect to sql server

For the following code you have to enable mssql in the php.ini as described at this link: http://www.php.net/manual/en/mssql.installation.php

$myServer = "10.85.80.229";
$myUser = "root";
$myPass = "pass";
$myDB = "testdb";

$conn = mssql_connect($myServer,$myUser,$myPass);
if (!$conn)
{ 
  die('Not connected : ' . mssql_get_last_message());
} 
$db_selected = mssql_select_db($myDB, $conn);
if (!$db_selected) 
{
  die ('Can\'t use db : ' . mssql_get_last_message());
} 

How to split a string into a list?

shlex has a .split() function. It differs from str.split() in that it does not preserve quotes and treats a quoted phrase as a single word:

>>> import shlex
>>> shlex.split("sudo echo 'foo && bar'")
['sudo', 'echo', 'foo && bar']

NB: it works well for Unix-like command line strings. It doesn't work for natural-language processing.

Excel Calculate the date difference from today from a cell of "7/6/2012 10:26:42"

=ROUND((TODAY()-A1)/365,0) will provide number of years between date in cell A1 and today's date

How do I create a constant in Python?

Here is an implementation of a "Constants" class, which creates instances with read-only (constant) attributes. E.g. can use Nums.PI to get a value that has been initialized as 3.14159, and Nums.PI = 22 raises an exception.

# ---------- Constants.py ----------
class Constants(object):
    """
    Create objects with read-only (constant) attributes.
    Example:
        Nums = Constants(ONE=1, PI=3.14159, DefaultWidth=100.0)
        print 10 + Nums.PI
        print '----- Following line is deliberate ValueError -----'
        Nums.PI = 22
    """

    def __init__(self, *args, **kwargs):
        self._d = dict(*args, **kwargs)

    def __iter__(self):
        return iter(self._d)

    def __len__(self):
        return len(self._d)

    # NOTE: This is only called if self lacks the attribute.
    # So it does not interfere with get of 'self._d', etc.
    def __getattr__(self, name):
        return self._d[name]

    # ASSUMES '_..' attribute is OK to set. Need this to initialize 'self._d', etc.
    #If use as keys, they won't be constant.
    def __setattr__(self, name, value):
        if (name[0] == '_'):
            super(Constants, self).__setattr__(name, value)
        else:
            raise ValueError("setattr while locked", self)

if (__name__ == "__main__"):
    # Usage example.
    Nums = Constants(ONE=1, PI=3.14159, DefaultWidth=100.0)
    print 10 + Nums.PI
    print '----- Following line is deliberate ValueError -----'
    Nums.PI = 22

Thanks to @MikeGraham 's FrozenDict, which I used as a starting point. Changed, so instead of Nums['ONE'] the usage syntax is Nums.ONE.

And thanks to @Raufio's answer, for idea to override __ setattr __.

Or for an implementation with more functionality, see @Hans_meine 's named_constants at GitHub

How to go from Blob to ArrayBuffer

Just to complement Mr @potatosalad answer.

You don't actually need to access the function scope to get the result on the onload callback, you can freely do the following on the event parameter:

var arrayBuffer;
var fileReader = new FileReader();
fileReader.onload = function(event) {
    arrayBuffer = event.target.result;
};
fileReader.readAsArrayBuffer(blob);

Why this is better? Because then we may use arrow function without losing the context

var fileReader = new FileReader();
fileReader.onload = (event) => {
    this.externalScopeVariable = event.target.result;
};
fileReader.readAsArrayBuffer(blob);

How do I extend a class with c# extension methods?

They provide the capability to extend existing types by adding new methods with no modifications necessary to the type. Calling methods from objects of the extended type within an application using instance method syntax is known as ‘‘extending’’ methods. Extension methods are not instance members on the type. The key point to remember is that extension methods, defined as static methods, are in scope only when the namespace is explicitly imported into your application source code via the using directive. Even though extension methods are defined as static methods, they are still called using instance syntax.

Check the full example here http://www.dotnetreaders.com/articles/Extension_methods_in_C-sharp.net,Methods_in_C_-sharp/201

Example:

class Extension
    {
        static void Main(string[] args)
        {
            string s = "sudhakar";
            Console.WriteLine(s.GetWordCount());
            Console.ReadLine();
        }

    }
    public static class MyMathExtension
    {

        public static int GetWordCount(this System.String mystring)
        {
            return mystring.Length;
        }
    }

How to get a URL parameter in Express?

If you want to grab the query parameter value in the URL, follow below code pieces

//url.localhost:8888/p?tagid=1234
req.query.tagid
OR
req.param.tagid

If you want to grab the URL parameter using Express param function

Express param function to grab a specific parameter. This is considered middleware and will run before the route is called.

This can be used for validations or grabbing important information about item.

An example for this would be:

// parameter middleware that will run before the next routes
app.param('tagid', function(req, res, next, tagid) {

// check if the tagid exists
// do some validations
// add something to the tagid
var modified = tagid+ '123';

// save name to the request
req.tagid= modified;

next();
});

// http://localhost:8080/api/tags/98
app.get('/api/tags/:tagid', function(req, res) {
// the tagid was found and is available in req.tagid
res.send('New tag id ' + req.tagid+ '!');
});

unexpected T_VARIABLE, expecting T_FUNCTION

You can not put

$connection = sqlite_open("[path]/data/users.sqlite", 0666);

outside the class construction. You have to put that line inside a function or the constructor but you can not place it where you have now.

Rename multiple columns by names

If the table contains two columns with the same name then the code goes like this,

rename(df,newname=oldname.x,newname=oldname.y)

How do I bind a WPF DataGrid to a variable number of columns?

You might be able to do this with AutoGenerateColumns and a DataTemplate. I'm not positive if it would work without a lot of work, you would have to play around with it. Honestly if you have a working solution already I wouldn't make the change just yet unless there's a big reason. The DataGrid control is getting very good but it still needs some work (and I have a lot of learning left to do) to be able to do dynamic tasks like this easily.

Getting year in moment.js

The year() function just retrieves the year component of the underlying Date object, so it returns a number.

Calling format('YYYY') will invoke moment's string formatting functions, which will parse the format string supplied, and build a new string containing the appropriate data. Since you only are passing YYYY, then the result will be a string containing the year.

If all you need is the year, then use the year() function. It will be faster, as there is less work to do.

Do note that while years are the same in this regard, months are not! Calling format('M') will return months in the range 1-12. Calling month() will return months in the range 0-11. This is due to the same behavior of the underlying Date object.

Add line break to ::after or ::before pseudo-element content

Nice article explaining the basics (does not cover line breaks, however).

A Whole Bunch of Amazing Stuff Pseudo Elements Can Do

If you need to have two inline elements where one breaks into the next line within another element, you can accomplish this by adding a pseudo-element :after with content:'\A' and white-space: pre

HTML

<h3>
    <span class="label">This is the main label</span>
    <span class="secondary-label">secondary label</span>
</h3>

CSS

.label:after {
    content: '\A';
    white-space: pre;
}

Convert generator object to list for debugging

Simply call list on the generator.

lst = list(gen)
lst

Be aware that this affects the generator which will not return any further items.

You also cannot directly call list in IPython, as it conflicts with a command for listing lines of code.

Tested on this file:

def gen():
    yield 1
    yield 2
    yield 3
    yield 4
    yield 5
import ipdb
ipdb.set_trace()

g1 = gen()

text = "aha" + "bebe"

mylst = range(10, 20)

which when run:

$ python code.py 
> /home/javl/sandbox/so/debug/code.py(10)<module>()
      9 
---> 10 g1 = gen()
     11 

ipdb> n
> /home/javl/sandbox/so/debug/code.py(12)<module>()
     11 
---> 12 text = "aha" + "bebe"
     13 

ipdb> lst = list(g1)
ipdb> lst
[1, 2, 3, 4, 5]
ipdb> q
Exiting Debugger.

General method for escaping function/variable/debugger name conflicts

There are debugger commands p and pp that will print and prettyprint any expression following them.

So you could use it as follows:

$ python code.py 
> /home/javl/sandbox/so/debug/code.py(10)<module>()
      9 
---> 10 g1 = gen()
     11 

ipdb> n
> /home/javl/sandbox/so/debug/code.py(12)<module>()
     11 
---> 12 text = "aha" + "bebe"
     13 

ipdb> p list(g1)
[1, 2, 3, 4, 5]
ipdb> c

There is also an exec command, called by prefixing your expression with !, which forces debugger to take your expression as Python one.

ipdb> !list(g1)
[]

For more details see help p, help pp and help exec when in debugger.

ipdb> help exec
(!) statement
Execute the (one-line) statement in the context of
the current stack frame.
The exclamation point can be omitted unless the first word
of the statement resembles a debugger command.
To assign to a global variable you must always prefix the
command with a 'global' command, e.g.:
(Pdb) global list_options; list_options = ['-l']

How to set a variable inside a loop for /F

The following should work:

setlocal EnableDelayedExpansion
for /F "tokens=*" %%a in ('type %FileName%') do (
    set "z=%%a"
    echo %z%
    echo %%a
)

Calling multiple JavaScript functions on a button click

Because you're returning from the first method call, the second doesn't execute.

Try something like

OnClientClick="var b = validateView();ShowDiv1(); return b"

or reverse the situation,

OnClientClick="ShowDiv1();return validateView();"

or if there is a dependency of div1 on the validation routine.

OnClientClick="var b = validateView(); if (b) ShowDiv1(); return b"

What might be best is to encapsulate multiple inline statements into a mini function like so, to simplify the call:

// change logic to suit taste
function clicked()  {
    var b = validateView(); 
    if (b) 
        ShowDiv1()
    return b;
}

and then

OnClientClick="return clicked();"

How to convert a String to Bytearray

String.prototype.encodeHex = function () {
    return this.split('').map(e => e.charCodeAt())
};

String.prototype.decodeHex = function () {    
    return this.map(e => String.fromCharCode(e)).join('')
};

How can I "reset" an Arduino board?

I just spent the last five hours searching for a solution to this problem (serial port COM3 already in use and grayed out serial port)...I tried everything every forum and Q&A site I could find suggested, including this one...

What finally fixed it (got rid of the last code I'd input that got stuck and uploaded simple blink function)?

Follow this link -- http://arduino.cc/en/guide/windows and follow the instructions for installing the drivers. My driver was "already up to date", but following these steps fixed the glitch. I am now a happy camper once again.

Note: Resetting the board manually with the button on the chip, or digitally through miscellaneous codes on the Internet did not work to fix this problem, because the signal was somehow blocked/confused between my Arduino Uno and the port in my laptop. Updating the drivers is like a reset for the "serial port already in use" problem.

At least so far...

Javascript getElementById based on a partial string

I'm not entirely sure I know what you're asking about, but you can use string functions to create the actual ID that you're looking for.

var base = "common";
var num = 3;

var o = document.getElementById(base + num);  // will find id="common3"

If you don't know the actual ID, then you can't look up the object with getElementById, you'd have to find it some other way (by class name, by tag type, by attribute, by parent, by child, etc...).

Now that you've finally given us some of the HTML, you could use this plain JS to find all form elements that have an ID that starts with "poll-":

// get a list of all form objects that have the right type of ID
function findPollForms() {
    var list = getElementsByTagName("form");
    var results = [];
    for (var i = 0; i < list.length; i++) {
        var id = list[i].id;
        if (id && id.search(/^poll-/) != -1) {
            results.push(list[i]);
        }
    }
    return(results);
}

// return the ID of the first form object that has the right type of ID
function findFirstPollFormID() {
    var list = getElementsByTagName("form");
    var results = [];
    for (var i = 0; i < list.length; i++) {
        var id = list[i].id;
        if (id && id.search(/^poll-/) != -1) {
            return(id);
        }
    }
    return(null);
}

Using Python String Formatting with Lists

Here is a one liner. A little improvised answer using format with print() to iterate a list.

How about this (python 3.x):

sample_list = ['cat', 'dog', 'bunny', 'pig']
print("Your list of animals are: {}, {}, {} and {}".format(*sample_list))

Read the docs here on using format().

How to start a background process in Python?

Both capture output and run on background with threading

As mentioned on this answer, if you capture the output with stdout= and then try to read(), then the process blocks.

However, there are cases where you need this. For example, I wanted to launch two processes that talk over a port between them, and save their stdout to a log file and stdout.

The threading module allows us to do that.

First, have a look at how to do the output redirection part alone in this question: Python Popen: Write to stdout AND log file simultaneously

Then:

main.py

#!/usr/bin/env python3

import os
import subprocess
import sys
import threading

def output_reader(proc, file):
    while True:
        byte = proc.stdout.read(1)
        if byte:
            sys.stdout.buffer.write(byte)
            sys.stdout.flush()
            file.buffer.write(byte)
        else:
            break

with subprocess.Popen(['./sleep.py', '0'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) as proc1, \
     subprocess.Popen(['./sleep.py', '10'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) as proc2, \
     open('log1.log', 'w') as file1, \
     open('log2.log', 'w') as file2:
    t1 = threading.Thread(target=output_reader, args=(proc1, file1))
    t2 = threading.Thread(target=output_reader, args=(proc2, file2))
    t1.start()
    t2.start()
    t1.join()
    t2.join()

sleep.py

#!/usr/bin/env python3

import sys
import time

for i in range(4):
    print(i + int(sys.argv[1]))
    sys.stdout.flush()
    time.sleep(0.5)

After running:

./main.py

stdout get updated every 0.5 seconds for every two lines to contain:

0
10
1
11
2
12
3
13

and each log file contains the respective log for a given process.

Inspired by: https://eli.thegreenplace.net/2017/interacting-with-a-long-running-child-process-in-python/

Tested on Ubuntu 18.04, Python 3.6.7.

Prevent multiple instances of a given app in .NET?

Simply using a StreamWriter, how about this?

System.IO.File.StreamWriter OpenFlag = null;   //globally

and

try
{
    OpenFlag = new StreamWriter(Path.GetTempPath() + "OpenedIfRunning");
}
catch (System.IO.IOException) //file in use
{
    Environment.Exit(0);
}

How can I set the default timezone in node.js?

Sometimes you may be running code on a virtual server elsewhere - That can get muddy when running NODEJS or other flavors.

Here is a fix that will allow you to use any timezone easily.

Check here for list of timezones

Just put your time zone phrase within the brackets of your FORMAT line.

In this case - I am converting EPOCH to Eastern.

//RE: https://www.npmjs.com/package/date-and-time
const date = require('date-and-time');

let unixEpochTime = (seconds * 1000);
const dd=new Date(unixEpochTime);
let myFormattedDateTime = date.format(dd, 'YYYY/MM/DD HH:mm:ss A [America/New_York]Z');
let myFormattedDateTime24 = date.format(dd, 'YYYY/MM/DD HH:mm:ss [America/New_York]Z');

fetch from origin with deleted remote branches?

You need to do the following

git fetch -p

This will update the local database of remote branches.

How to use 'find' to search for files created on a specific date?

@Max: is right about the creation time.

However, if you want to calculate the elapsed days argument for one of the -atime, -ctime, -mtime parameters, you can use the following expression

ELAPSED_DAYS=$(( ( $(date +%s) - $(date -d '2008-09-24' +%s) ) / 60 / 60 / 24 - 1 ))

Replace "2008-09-24" with whatever date you want and ELAPSED_DAYS will be set to the number of days between then and today. (Update: subtract one from the result to align with find's date rounding.)

So, to find any file modified on September 24th, 2008, the command would be:

find . -type f -mtime $(( ( $(date +%s) - $(date -d '2008-09-24' +%s) ) / 60 / 60 / 24 - 1 ))

This will work if your version of find doesn't support the -newerXY predicates mentioned in @Arve:'s answer.

Merge two json/javascript arrays in to one array

Upon first appearance, the word "merg" leads one to think you need to use .extend, which is the proper jQuery way to "merge" JSON objects. However, $.extend(true, {}, json1, json2); will cause all values sharing the same key name to be overridden by the latest supplied in the params. As review of your question shows, this is undesired.

What you seek is a simple javascript function known as .concat. Which would work like:

var finalObj = json1.concat(json2);

While this is not a native jQuery function, you could easily add it to the jQuery library for simple future use as follows:

;(function($) {
    if (!$.concat) {
        $.extend({
            concat: function() {
                return Array.prototype.concat.apply([], arguments);
            }
        });
    }
})(jQuery);

And then recall it as desired like:

var finalObj = $.concat(json1, json2);

You can also use it for multiple array objects of this type with a like:

var finalObj = $.concat(json1, json2, json3, json4, json5, ....);

And if you really want it jQuery style and very short and sweet (aka minified)

;(function(a){a.concat||a.extend({concat:function(){return Array.prototype.concat.apply([],arguments);}})})(jQuery);

_x000D_
_x000D_
;(function($){$.concat||$.extend({concat:function(){return Array.prototype.concat.apply([],arguments);}})})(jQuery);_x000D_
_x000D_
$(function() {_x000D_
    var json1 = [{id:1, name: 'xxx'}],_x000D_
        json2 = [{id:2, name: 'xyz'}],_x000D_
        json3 = [{id:3, name: 'xyy'}],_x000D_
        json4 = [{id:4, name: 'xzy'}],_x000D_
        json5 = [{id:5, name: 'zxy'}];_x000D_
    _x000D_
    console.log(Array(10).join('-')+'(json1, json2, json3)'+Array(10).join('-'));_x000D_
    console.log($.concat(json1, json2, json3));_x000D_
    console.log(Array(10).join('-')+'(json1, json2, json3, json4, json5)'+Array(10).join('-'));_x000D_
    console.log($.concat(json1, json2, json3, json4, json5));_x000D_
    console.log(Array(10).join('-')+'(json4, json1, json2, json5)'+Array(10).join('-'));_x000D_
    console.log($.concat(json4, json1, json2, json5));_x000D_
});
_x000D_
center { padding: 3em; }
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<center>See Console Log</center>
_x000D_
_x000D_
_x000D_

jsFiddle

Jquery show/hide table rows

Change your black and white IDs to classes instead (duplicate IDs are invalid), add 2 buttons with the proper IDs, and do this:

var rows = $('table.someclass tr');

$('#showBlackButton').click(function() {
    var black = rows.filter('.black').show();
    rows.not( black ).hide();
});

$('#showWhiteButton').click(function() {
    var white = rows.filter('.white').show();
    rows.not( white ).hide();
});

$('#showAll').click(function() {
    rows.show();
});

<button id="showBlackButton">show black</button>
<button id="showWhiteButton">show white</button>
<button id="showAll">show all</button>

<table class="someclass" border="0" cellpadding="0" cellspacing="0" summary="bla bla bla">
    <caption>bla bla bla</caption>
    <thead>
          <tr class="black">
            ...
          </tr>
    </thead>
    <tbody>
        <tr class="white">
            ...
        </tr>
        <tr class="black">
           ...
        </tr>
    </tbody>
</table>

It uses the filter()[docs] method to filter the rows with the black or white class (depending on the button).

Then it uses the not()[docs] method to do the opposite filter, excluding the black or white rows that were previously found.


EDIT: You could also pass a selector to .not() instead of the previously found set. It may perform better that way:

rows.not( `.black` ).hide();

// ...

rows.not( `.white` ).hide();

...or better yet, just keep a cached set of both right from the start:

var rows = $('table.someclass tr');
var black = rows.filter('.black');
var white = rows.filter('.white');

$('#showBlackButton').click(function() {
    black.show();
    white.hide();
});

$('#showWhiteButton').click(function() {
    white.show();
    black.hide();
});

Node.js Logging

Log4js is one of the most popular logging library for nodejs application.

It supports many cool features:

  1. Coloured console logging
  2. Replacement of node's console.log functions (optional)
  3. File appender, with log rolling based on file size
  4. SMTP, GELF, hook.io, Loggly appender
  5. Multiprocess appender (useful when you've got worker processes)
  6. A logger for connect/express servers
  7. Configurable log message layout/patterns
  8. Different log levels for different log categories (make some parts of your app log as DEBUG, others only ERRORS, etc.)

Example:

  1. Installation: npm install log4js

  2. Configuration (./config/log4js.json):

    {"appenders": [
        {
            "type": "console",
            "layout": {
                "type": "pattern",
                "pattern": "%m"
            },
            "category": "app"
        },{
            "category": "test-file-appender",
            "type": "file",
            "filename": "log_file.log",
            "maxLogSize": 10240,
            "backups": 3,
            "layout": {
                "type": "pattern",
                "pattern": "%d{dd/MM hh:mm} %-5p %m"
            }
        }
    ],
    "replaceConsole": true }
    
  3. Usage:

    var log4js = require( "log4js" );
    log4js.configure( "./config/log4js.json" );
    var logger = log4js.getLogger( "test-file-appender" );
    // log4js.getLogger("app") will return logger that prints log to the console
    logger.debug("Hello log4js");// store log in file
    

Detecting Enter keypress on VB.NET

Make sure the form KeyPreview property is set to true.

Private Sub Form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress
    If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Return) Then
        SendKeys.Send("{TAB}")
        e.Handled = True
    End If

End Sub

How to negate code in "if" statement block in JavaScript -JQuery like 'if not then..'

Try negation operator ! before $(this):

if (!$(this).parent().next().is('ul')){

Python NameError: name is not defined

Note that sometimes you will want to use the class type name inside its own definition, for example when using Python Typing module, e.g.

class Tree:
    def __init__(self, left: Tree, right: Tree):
        self.left = left
        self.right = right

This will also result in

NameError: name 'Tree' is not defined

That's because the class has not been defined yet at this point. The workaround is using so called Forward Reference, i.e. wrapping a class name in a string, i.e.

class Tree:
    def __init__(self, left: 'Tree', right: 'Tree'):
        self.left = left
        self.right = right

Reading tab-delimited file with Pandas - works on Windows, but not on Mac

The biggest clue is the rows are all being returned on one line. This indicates line terminators are being ignored or are not present.

You can specify the line terminator for csv_reader. If you are on a mac the lines created will end with \rrather than the linux standard \n or better still the suspenders and belt approach of windows with \r\n.

pandas.read_csv(filename, sep='\t', lineterminator='\r')

You could also open all your data using the codecs package. This may increase robustness at the expense of document loading speed.

import codecs

doc = codecs.open('document','rU','UTF-16') #open for reading with "universal" type set

df = pandas.read_csv(doc, sep='\t')

How do I reference a local image in React?

You need to wrap you image source path within {}

<img src={'path/to/one.jpeg'} />

You need to use require if using webpack

<img src={require('path/to/one.jpeg')} />

Get Cell Value from Excel Sheet with Apache Poi

You have to use the FormulaEvaluator, as shown here. This will return a value that is either the value present in the cell or the result of the formula if the cell contains such a formula :

FileInputStream fis = new FileInputStream("/somepath/test.xls");
Workbook wb = new HSSFWorkbook(fis); //or new XSSFWorkbook("/somepath/test.xls")
Sheet sheet = wb.getSheetAt(0);
FormulaEvaluator evaluator = wb.getCreationHelper().createFormulaEvaluator();

// suppose your formula is in B3
CellReference cellReference = new CellReference("B3"); 
Row row = sheet.getRow(cellReference.getRow());
Cell cell = row.getCell(cellReference.getCol()); 

if (cell!=null) {
    switch (evaluator.evaluateFormulaCell(cell)) {
        case Cell.CELL_TYPE_BOOLEAN:
            System.out.println(cell.getBooleanCellValue());
            break;
        case Cell.CELL_TYPE_NUMERIC:
            System.out.println(cell.getNumericCellValue());
            break;
        case Cell.CELL_TYPE_STRING:
            System.out.println(cell.getStringCellValue());
            break;
        case Cell.CELL_TYPE_BLANK:
            break;
        case Cell.CELL_TYPE_ERROR:
            System.out.println(cell.getErrorCellValue());
            break;

        // CELL_TYPE_FORMULA will never occur
        case Cell.CELL_TYPE_FORMULA: 
            break;
    }
}

if you need the exact contant (ie the formla if the cell contains a formula), then this is shown here.

Edit : Added a few example to help you.

first you get the cell (just an example)

Row row = sheet.getRow(rowIndex+2);    
Cell cell = row.getCell(1);   

If you just want to set the value into the cell using the formula (without knowing the result) :

 String formula ="ABS((1-E"+(rowIndex + 2)+"/D"+(rowIndex + 2)+")*100)";    
 cell.setCellFormula(formula);    
 cell.setCellStyle(this.valueRightAlignStyleLightBlueBackground);

if you want to change the message if there is an error in the cell, you have to change the formula to do so, something like

IF(ISERR(ABS((1-E3/D3)*100));"N/A"; ABS((1-E3/D3)*100))

(this formula check if the evaluation return an error and then display the string "N/A", or the evaluation if this is not an error).

if you want to get the value corresponding to the formula, then you have to use the evaluator.

Hope this help,
Guillaume

Creating a PHP header/footer

the simpler, the better.

index.php

<? 
if (empty($_SERVER['QUERY_STRING'])) { 
  $name="index"; 
} else { 
  $name=basename($_SERVER['QUERY_STRING']); 
} 
$file="txt/".$name.".htm"; 
if (is_readable($file)) { 
  include 'header.php';
  readfile($file);
} else { 
  header("HTTP/1.0 404 Not Found");
  exit;
} 
?>

header.php

<a href="index.php">Main page</a><br>
<a href=?about>About</a><br>
<a href=?links>Links</a><br>
<br><br> 

the actual static html pages stored in the txt folder in the page.htm format

Why doesn't JUnit provide assertNotEquals methods?

I agree totally with the OP point of view. Assert.assertFalse(expected.equals(actual)) is not a natural way to express an inequality.
But I would argue that further than Assert.assertEquals(), Assert.assertNotEquals() works but is not user friendly to document what the test actually asserts and to understand/debug as the assertion fails.
So yes JUnit 4.11 and JUnit 5 provides Assert.assertNotEquals() (Assertions.assertNotEquals() in JUnit 5) but I really avoid using them.

As alternative, to assert the state of an object I general use a matcher API that digs into the object state easily, that document clearly the intention of the assertions and that is very user friendly to understand the cause of the assertion failure.

Here is an example.
Suppose I have an Animal class which I want to test the createWithNewNameAndAge() method, a method that creates a new Animal object by changing its name and its age but by keeping its favorite food.
Suppose I use Assert.assertNotEquals() to assert that the original and the new objects are different.
Here is the Animal class with a flawed implementation of createWithNewNameAndAge() :

public class Animal {

    private String name;
    private int age;
    private String favoriteFood;

    public Animal(String name, int age, String favoriteFood) {
        this.name = name;
        this.age = age;
        this.favoriteFood = favoriteFood;
    }

    // Flawed implementation : use this.name and this.age to create the 
    // new Animal instead of using the name and age parameters
    public Animal createWithNewNameAndAge(String name, int age) {
        return new Animal(this.name, this.age, this.favoriteFood);
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getFavoriteFood() {
        return favoriteFood;
    }

    @Override
    public String toString() {
        return "Animal [name=" + name + ", age=" + age + ", favoriteFood=" + favoriteFood + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + ((favoriteFood == null) ? 0 : favoriteFood.hashCode());
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Animal)) return false;

        Animal other = (Animal) obj;
        return age == other.age && favoriteFood.equals(other.favoriteFood) &&
                name.equals(other.name);
    }

}

JUnit 4.11+ (or JUnit 5) both as test runner and assertion tool

@Test
void assertListNotEquals_JUnit_way() {
    Animal scoubi = new Animal("scoubi", 10, "hay");
    Animal littleScoubi = scoubi.createWithNewNameAndAge("little scoubi", 1);
    Assert.assertNotEquals(scoubi, littleScoubi);
}

The test fails as expected but the cause provided to the developer is really not helpful. It just says that the values should be different and output the toString() result invoked on the actual Animal parameter :

java.lang.AssertionError: Values should be different. Actual: Animal

[name=scoubi, age=10, favoriteFood=hay]

at org.junit.Assert.fail(Assert.java:88)

Ok the objects are not equals. But where is the problem ?
Which field is not correctly valued in the tested method ? One ? Two ? All of them ?
To discover it you have to dig in the createWithNewNameAndAge() implementation/use a debugger while the testing API would be much more friendly if it would make for us the differential between which is expected and which is gotten.


JUnit 4.11 as test runner and a test Matcher API as assertion tool

Here the same scenario of test but that uses AssertJ (an excellent test matcher API) to make the assertion of the Animal state: :

import org.assertj.core.api.Assertions;

@Test
void assertListNotEquals_AssertJ() {
    Animal scoubi = new Animal("scoubi", 10, "hay");
    Animal littleScoubi = scoubi.createWithNewNameAndAge("little scoubi", 1);
    Assertions.assertThat(littleScoubi)
              .extracting(Animal::getName, Animal::getAge, Animal::getFavoriteFood)
              .containsExactly("little scoubi", 1, "hay");
}

Of course the test still fails but this time the reason is clearly stated :

java.lang.AssertionError:

Expecting:

<["scoubi", 10, "hay"]>

to contain exactly (and in same order):

<["little scoubi", 1, "hay"]>

but some elements were not found:

<["little scoubi", 1]>

and others were not expected:

<["scoubi", 10]>

at junit5.MyTest.assertListNotEquals_AssertJ(MyTest.java:26)

We can read that for Animal::getName, Animal::getAge, Animal::getFavoriteFood values of the returned Animal, we expect to have these value :

"little scoubi", 1, "hay" 

but we have had these values :

"scoubi", 10, "hay"

So we know where investigate : name and age are not correctly valued. Additionally, the fact of specifying the hay value in the assertion of Animal::getFavoriteFood() allows also to more finely assert the returned Animal. We want that the objects be not the same for some properties but not necessarily for every properties.
So definitely, using a matcher API is much more clear and flexible.

What's is the difference between include and extend in use case diagram?

The difference between both has been explained here. But what has not been explained is the fact that <<include>> and <<extend>> should simply not be used at all.

If you read Bittner/Spence you know that use cases are about synthesis, not analysis. A re-use of use cases is nonsense. It clearly shows that you have cut your domain wrongly. Added value must be unique per se. The only re-use of added value I know is franchise. So if you are in burger business, nice. But everywhere else your task as BA is to try to find an USP. And that must be presented in good use cases.

Whenever I see people using one of those relations it is when they try to do functional decomposition. And that's plain wrong.

To put it simple: if you can answer your boss without hesitation "I have done ..." then the "..." is your use case since you got money for doing it. (That will also make clear that "login" is not a use case at all.)

In that respect, finding self standing use cases that are included or extend other use cases is very unlikely. Eventually you can use <<extend>> to show optionality of your system, i.e. some licensing schema which allows to include use cases for some licenses or to omit them. But else - just avoid them.

"Large data" workflows using pandas

If your datasets are between 1 and 20GB, you should get a workstation with 48GB of RAM. Then Pandas can hold the entire dataset in RAM. I know its not the answer you're looking for here, but doing scientific computing on a notebook with 4GB of RAM isn't reasonable.

Achieving white opacity effect in html/css

If you can't use rgba due to browser support, and you don't want to include a semi-transparent white PNG, you will have to create two positioned elements. One for the white box, with opacity, and one for the overlaid text, solid.

_x000D_
_x000D_
body { background: red; }_x000D_
_x000D_
.box { position: relative; z-index: 1; }_x000D_
.box .back {_x000D_
    position: absolute; z-index: 1;_x000D_
    top: 0; left: 0; width: 100%; height: 100%;_x000D_
    background: white; opacity: 0.75;_x000D_
}_x000D_
.box .text { position: relative; z-index: 2; }_x000D_
_x000D_
body.browser-ie8 .box .back { filter: alpha(opacity=75); }
_x000D_
<!--[if lt IE 9]><body class="browser-ie8"><![endif]-->_x000D_
<!--[if gte IE 9]><!--><body><!--<![endif]-->_x000D_
    <div class="box">_x000D_
        <div class="back"></div>_x000D_
        <div class="text">_x000D_
            Lorem ipsum dolor sit amet blah blah boogley woogley oo._x000D_
        </div>_x000D_
    </div>_x000D_
</body>
_x000D_
_x000D_
_x000D_

What precisely does 'Run as administrator' do?

UPDATE

"Run as Aministrator" is just a command, enabling the program to continue some operations that require the Administrator privileges, without displaying the UAC alerts.

Even if your user is a member of administrators group, some applications like yours need the Administrator privileges to continue running, because the application is considered not safe, if it is doing some special operation, like editing a system file or something else. This is the reason why Windows needs the Administrator privilege to execute the application and it notifies you with a UAC alert. Not all applications need an Amnistrator account to run, and some applications, like yours, need the Administrator privileges.

If you execute the application with 'run as administrator' command, you are notifying the system that your application is safe and doing something that requires the administrator privileges, with your confirm.

If you want to avoid this, just disable the UAC on Control Panel.

If you want to go further, read the question Difference between "Run as Administrator" and Windows 7 Administrators Group on Microsoft forum or this SuperUser question.

How to discard local commits in Git?

I have seen instances where the remote became out of sync and needed to be updated. If a reset --hard or a branch -D fail to work, try

git pull origin
git reset --hard 

How can I print out C++ map values?

for(map<string, pair<string,string> >::const_iterator it = myMap.begin();
    it != myMap.end(); ++it)
{
    std::cout << it->first << " " << it->second.first << " " << it->second.second << "\n";
}

In C++11, you don't need to spell out map<string, pair<string,string> >::const_iterator. You can use auto

for(auto it = myMap.cbegin(); it != myMap.cend(); ++it)
{
    std::cout << it->first << " " << it->second.first << " " << it->second.second << "\n";
}

Note the use of cbegin() and cend() functions.

Easier still, you can use the range-based for loop:

for(auto elem : myMap)
{
   std::cout << elem.first << " " << elem.second.first << " " << elem.second.second << "\n";
}

How to check a boolean condition in EL?

You can have a look at the EL (expression language) description here.

Both your code are correct, but I prefer the second one, as comparing a boolean to true or false is redundant.

For better readibility, you can also use the not operator:

<c:if test="${not theBooleanVariable}">It's false!</c:if>

How to make <input type="file"/> accept only these types?

IMPORTANT UPDATE:

Due to use of only application/msword, application/vnd.ms-excel, application/vnd.ms-powerpoint... allows only till 2003 MS products, and not newest. I've found this:

application/msword, application/vnd.openxmlformats-officedocument.wordprocessingml.document, application/vnd.ms-powerpoint, application/vnd.openxmlformats-officedocument.presentationml.slideshow, application/vnd.openxmlformats-officedocument.presentationml.presentation

And that includes the new ones. For other files, you can retrieve the MIME TYPE in your file by this way (pardon the lang)(in MIME list types, there aren't this ones):

enter image description here

You can select & copy the type of content

How to download/checkout a project from Google Code in Windows?

Thanks Mr. Tom Chantler adding that to get the exe http://downloadsvn.codeplex.com/ to pull the SVN source

just note that suppose you're downloading the below project: you have to enter exactly the following to donwload it in the exe URL:

http://myproject.googlecode.com/svn/trunk/

developer not taking care of appending the h t t p : / / if it does not exist. Hope it saves somebody's time.

How do I use the lines of a file as arguments of a command?

After editing @Wesley Rice's answer a couple times, I decided my changes were just getting too big to continue changing his answer instead of writing my own. So, I decided I need to write my own!

Read each line of a file in and operate on it line-by-line like this:

#!/bin/bash
input="/path/to/txt/file"
while IFS= read -r line
do
  echo "$line"
done < "$input"

This comes directly from author Vivek Gite here: https://www.cyberciti.biz/faq/unix-howto-read-line-by-line-from-file/. He gets the credit!

Syntax: Read file line by line on a Bash Unix & Linux shell:
1. The syntax is as follows for bash, ksh, zsh, and all other shells to read a file line by line
2. while read -r line; do COMMAND; done < input.file
3. The -r option passed to read command prevents backslash escapes from being interpreted.
4. Add IFS= option before read command to prevent leading/trailing whitespace from being trimmed -
5. while IFS= read -r line; do COMMAND_on $line; done < input.file


And now to answer this now-closed question which I also had: Is it possible to `git add` a list of files from a file? - here's my answer:

Note that FILES_STAGED is a variable containing the absolute path to a file which contains a bunch of lines where each line is a relative path to a file I'd like to do git add on. This code snippet is about to become part of the "eRCaGuy_dotfiles/useful_scripts/sync_git_repo_to_build_machine.sh" file in this project, to enable easy syncing of files in development from one PC (ex: a computer I code on) to another (ex: a more powerful computer I build on): https://github.com/ElectricRCAircraftGuy/eRCaGuy_dotfiles.

while IFS= read -r line
do
    echo "  git add \"$line\""
    git add "$line" 
done < "$FILES_STAGED"

References:

  1. Where I copied my answer from: https://www.cyberciti.biz/faq/unix-howto-read-line-by-line-from-file/
  2. For loop syntax: https://www.cyberciti.biz/faq/bash-for-loop/

Related:

  1. How to read contents of file line-by-line and do git add on it: Is it possible to `git add` a list of files from a file?

BigDecimal setScale and round

There is indeed a big difference, which you should keep in mind. setScale really set the scale of your number whereas round does round your number to the specified digits BUT it "starts from the leftmost digit of exact result" as mentioned within the jdk. So regarding your sample the results are the same, but try 0.0034 instead. Here's my note about that on my blog:

http://araklefeistel.blogspot.com/2011/06/javamathbigdecimal-difference-between.html

LINQ Join with Multiple Conditions in On Clause

You just need to name the anonymous property the same on both sides

on new { t1.ProjectID, SecondProperty = true } equals 
   new { t2.ProjectID, SecondProperty = t2.Completed } into j1

Based on the comments of @svick, here is another implementation that might make more sense:

from t1 in Projects
from t2 in Tasks.Where(x => t1.ProjectID == x.ProjectID && x.Completed == true)
                .DefaultIfEmpty()
select new { t1.ProjectName, t2.TaskName }

How to have a default option in Angular.js select box

You can simply use ng-init like this

<select ng-init="somethingHere = options[0]" 
        ng-model="somethingHere" 
        ng-options="option.name for option in options">
</select>

Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra/Mojave?

Cited from

Apple Developer Relations 10-Oct-2014 09:12 PM

After much deliberation, engineering has removed this feature. The file /etc/launchd.conf was intentionally removed for security reasons. As a workaround, you could run launchctl limit as root early during boot, perhaps from a LaunchDaemon. (...)

Solution:

Put code in to /Library/LaunchDaemons/com.apple.launchd.limit.plist by bash-script:

#!/bin/bash

echo '<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Label</key>
        <string>eicar</string>
        <key>ProgramArguments</key>
        <array>
                <string>/bin/launchctl</string>
                <string>limit</string>
                <string>core</string>
                <string>unlimited</string>
        </array>
        <key>RunAtLoad</key>
        <true/>
        <key>ServiceIPC</key>
        <false/>
</dict>
</plist>' | sudo tee /Library/LaunchDaemons/com.apple.launchd.limit.plist

How to get main window handle from process id?

I checked how .NET determines the main window.

My finding showed that it also uses EnumWindows().

This code should do it similarly to the .NET way:

struct handle_data {
    unsigned long process_id;
    HWND window_handle;
};

HWND find_main_window(unsigned long process_id)
{
    handle_data data;
    data.process_id = process_id;
    data.window_handle = 0;
    EnumWindows(enum_windows_callback, (LPARAM)&data);
    return data.window_handle;
}

BOOL CALLBACK enum_windows_callback(HWND handle, LPARAM lParam)
{
    handle_data& data = *(handle_data*)lParam;
    unsigned long process_id = 0;
    GetWindowThreadProcessId(handle, &process_id);
    if (data.process_id != process_id || !is_main_window(handle))
        return TRUE;
    data.window_handle = handle;
    return FALSE;   
}

BOOL is_main_window(HWND handle)
{   
    return GetWindow(handle, GW_OWNER) == (HWND)0 && IsWindowVisible(handle);
}

How to validate a credit card number

I hope the following two links help to solve your problem.

FYI, various credit cards are available in the world. So, your thought is wrong. Credit cards have some format. See the following links. The first one is pure JavaScript and the second one is using jQuery.

Demo:

_x000D_
_x000D_
function testCreditCard() {_x000D_
  myCardNo = document.getElementById('CardNumber').value;_x000D_
  myCardType = document.getElementById('CardType').value;_x000D_
  if (checkCreditCard(myCardNo, myCardType)) {_x000D_
    alert("Credit card has a valid format")_x000D_
  } else {_x000D_
    alert(ccErrors[ccErrorNo])_x000D_
  };_x000D_
}
_x000D_
<script src="https://www.braemoor.co.uk/software/_private/creditcard.js"></script>_x000D_
_x000D_
<!-- COPIED THE DEMO CODE FROM THE SOURCE WEBSITE (https://www.braemoor.co.uk/software/creditcard.shtml) -->_x000D_
_x000D_
<table>_x000D_
  <tbody>_x000D_
    <tr>_x000D_
      <td style="padding-right: 30px;">American Express</td>_x000D_
      <td>3400 0000 0000 009</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Carte Blanche</td>_x000D_
      <td>3000 0000 0000 04</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Discover</td>_x000D_
      <td>6011 0000 0000 0004</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Diners Club</td>_x000D_
      <td>3852 0000 0232 37</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>enRoute</td>_x000D_
      <td>2014 0000 0000 009</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>JCB</td>_x000D_
      <td>3530 111333300000</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>MasterCard</td>_x000D_
      <td>5500 0000 0000 0004</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Solo</td>_x000D_
      <td>6334 0000 0000 0004</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Switch</td>_x000D_
      <td>4903 0100 0000 0009</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Visa</td>_x000D_
      <td>4111 1111 1111 1111</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>Laser</td>_x000D_
      <td>6304 1000 0000 0008</td>_x000D_
    </tr>_x000D_
  </tbody>_x000D_
</table>_x000D_
<hr /> Card Number:_x000D_
<select tabindex="11" id="CardType" style="margin-left: 10px;">_x000D_
  <option value="AmEx">American Express</option>_x000D_
  <option value="CarteBlanche">Carte Blanche</option>_x000D_
  <option value="DinersClub">Diners Club</option>_x000D_
  <option value="Discover">Discover</option>_x000D_
  <option value="EnRoute">enRoute</option>_x000D_
  <option value="JCB">JCB</option>_x000D_
  <option value="Maestro">Maestro</option>_x000D_
  <option value="MasterCard">MasterCard</option>_x000D_
  <option value="Solo">Solo</option>_x000D_
  <option value="Switch">Switch</option>_x000D_
  <option value="Visa">Visa</option>_x000D_
  <option value="VisaElectron">Visa Electron</option>_x000D_
  <option value="LaserCard">Laser</option>_x000D_
</select> <input type="text" id="CardNumber" maxlength="24" size="24" style="margin-left: 10px;"> <button id="mybutton" type="button" onclick="testCreditCard();" style="margin-left: 10px; color: #f00;">Check</button>_x000D_
_x000D_
<p style="color: red; font-size: 10px;"> COPIED THE DEMO CODE FROM TEH SOURCE WEBSITE (https://www.braemoor.co.uk/software/creditcard.shtml) </p>
_x000D_
_x000D_
_x000D_