Programs & Examples On #Topshelf

Topshelf is a service hosting framework for building Windows services using .NET.

Adding item to Dictionary within loop

In your current code, what Dictionary.update() does is that it updates (update means the value is overwritten from the value for same key in passed in dictionary) the keys in current dictionary with the values from the dictionary passed in as the parameter to it (adding any new key:value pairs if existing) . A single flat dictionary does not satisfy your requirement , you either need a list of dictionaries or a dictionary with nested dictionaries.

If you want a list of dictionaries (where each element in the list would be a diciotnary of a entry) then you can make case_list as a list and then append case to it (instead of update) .

Example -

case_list = []
for entry in entries_list:
    case = {'key1': entry[0], 'key2': entry[1], 'key3':entry[2] }
    case_list.append(case)

Or you can also have a dictionary of dictionaries with the key of each element in the dictionary being entry1 or entry2 , etc and the value being the corresponding dictionary for that entry.

case_list = {}
for entry in entries_list:
    case = {'key1': value, 'key2': value, 'key3':value }
    case_list[entryname] = case  #you will need to come up with the logic to get the entryname.

SQL Query for Student mark functionality

My attempt - I'd start with the max mark and build from there

Schema:

CREATE TABLE Student (
  StudentId int,
  Name nvarchar(30),
  Details nvarchar(30)
)
CREATE TABLE Subject (
  SubjectId int,
  Name nvarchar(30)
)
CREATE TABLE Marks (
  StudentId int,
  SubjectId int,
  Mark int
)

Data:

INSERT INTO Student (StudentId, Name, Details) 
VALUES (1,'Alfred','AA'), (2,'Betty','BB'), (3,'Chris','CC')

INSERT INTO Subject (SubjectId, Name)
VALUES (1,'Maths'), (2, 'Science'), (3, 'English')

INSERT INTO Marks (StudentId, SubjectId, Mark)
VALUES 
(1,1,61),(1,2,75),(1,3,87),
(2,1,82),(2,2,64),(2,3,77),
(3,1,82),(3,2,83),(3,3,67)
GO

My query would have been:

;WITH MaxMarks AS (
  SELECT SubjectId, MAX(Mark) as MaxMark
    FROM Marks
    GROUP BY SubjectId
 )
SELECT s.Name as [StudentName], sub.Name AS [SubjectName],m.Mark
FROM MaxMarks mm
INNER JOIN Marks m 
ON m.SubjectId = mm.SubjectId 
AND m.Mark = mm.MaxMark
INNER JOIN Student s
ON s.StudentId = m.StudentId
INNER JOIN Subject sub
ON sub.SubjectId = mm.SubjectId

SQL Fiddle Example

  1. Find the max mark for each subject
  2. Join Marks, Student and Subject to find the relevant details of that highest mark

This also take care of duplicate students with the highest mark

Results:

STUDENTNAME SUBJECTNAME     MARK
Alfred  English     87
Betty   Maths           82
Chris   Maths           82
Chris   Science     83

javascript pushing element at the beginning of an array

Use unshift, which modifies the existing array by adding the arguments to the beginning:

TheArray.unshift(TheNewObject);

How can I get the DateTime for the start of the week?

   d = DateTime.Now;
            int dayofweek =(int) d.DayOfWeek;
            if (dayofweek != 0)
            {
                d = d.AddDays(1 - dayofweek);
            }
            else { d = d.AddDays(-6); }

Use HTML5 to resize an image before upload

If some of you, like me, encounter orientation problems I have combined the solutions here with a exif orientation fix

https://gist.github.com/SagiMedina/f00a57de4e211456225d3114fd10b0d0

When is it appropriate to use C# partial classes?

As an alternative to pre-compiler directives.

If you use pre-compiler directives (namely #IF DEBUG) then you end up with some gnarly looking code intermingled with your actual Release code.

You can create a seperate partial-class to contain this code, and either wrap the entire partial class in a directive, or omit that code-file from being sent to the compiler (effectively doing the same).

Maven compile: package does not exist

You do not include a <scope> tag in your dependency. If you add it, your dependency becomes something like:

<dependency>
     <groupId>org.openrdf.sesame</groupId>
     <artifactId>sesame-runtime</artifactId>
     <version>2.7.2</version>
     <scope> ... </scope>
</dependency>

The "scope" tag tells maven at which stage of the build your dependency is needed. Examples for the values to put inside are "test", "provided" or "runtime" (omit the quotes in your pom). I do not know your dependency so I cannot tell you what value to choose. Please consult the Maven documentation and the documentation of your dependency.

Oracle insert if not exists statement

Another approach would be to leverage the INSERT ALL syntax from oracle,

INSERT ALL 
    INTO table1(email, campaign_id) VALUES (email, campaign_id)
WITH source_data AS
 (SELECT '[email protected]' email,100 campaign_id
  FROM   dual
  UNION ALL
  SELECT '[email protected]' email,200 campaign_id
  FROM   dual)      
SELECT email
      ,campaign_id
FROM   source_data src
WHERE  NOT EXISTS (SELECT 1
        FROM   table1 dest
        WHERE  src.email = dest.email
        AND    src.campaign_id = dest.campaign_id);

INSERT ALL also allow us to perform a conditional insert into multiple tables based on a sub query as source.

There are some really clean and nice examples are there to refer.

  1. oracletutorial.com
  2. oracle-base.com/

In Matplotlib, what does the argument mean in fig.add_subplot(111)?

The answer from Constantin is spot on but for more background this behavior is inherited from Matlab.

The Matlab behavior is explained in the Figure Setup - Displaying Multiple Plots per Figure section of the Matlab documentation.

subplot(m,n,i) breaks the figure window into an m-by-n matrix of small subplots and selects the ithe subplot for the current plot. The plots are numbered along the top row of the figure window, then the second row, and so forth.

What was the strangest coding standard rule that you were forced to follow?

Giving numbers to our tables, like tbl47_[some name]

How to return 2 values from a Java method?

Return an Array Of Objects

private static Object[] f () 
{ 
     double x =1.0;  
     int y= 2 ;
     return new Object[]{Double.valueOf(x),Integer.valueOf(y)};  
}

Leading zeros for Int in Swift

Unlike the other answers that use a formatter, you can also just add an "0" text in front of each number inside of the loop, like this:

for myInt in 1...3 {
    println("0" + "\(myInt)")
}

But formatter is often better when you have to add suppose a designated amount of 0s for each seperate number. If you only need to add one 0, though, then it's really just your pick.

Constantly print Subprocess output while process is running

You can use iter to process lines as soon as the command outputs them: lines = iter(fd.readline, ""). Here's a full example showing a typical use case (thanks to @jfs for helping out):

from __future__ import print_function # Only Python 2.x
import subprocess

def execute(cmd):
    popen = subprocess.Popen(cmd, stdout=subprocess.PIPE, universal_newlines=True)
    for stdout_line in iter(popen.stdout.readline, ""):
        yield stdout_line 
    popen.stdout.close()
    return_code = popen.wait()
    if return_code:
        raise subprocess.CalledProcessError(return_code, cmd)

# Example
for path in execute(["locate", "a"]):
    print(path, end="")

List<String> to ArrayList<String> conversion issue

Arrays.asList does not return instance of java.util.ArrayListbut it returns instance of java.util.Arrays.ArrayList.

You will need to convert to ArrayList if you want to access ArrayList specific information

allWords.addAll(Arrays.asList(strTemp.toLowerCase().split("\\s+")));

Output in a table format in Java's System.out

Check this out. The author provides a simple but elegant solution which doesn't require any 3rd party library. http://www.ksmpartners.com/2013/08/nicely-formatted-tabular-output-in-java/

An example of the TableBuilder and sample output

Get string character by index - Java

You're pretty stuck with substring(), given your requirements. The standard way would be charAt(), but you said you won't accept a char data type.

JQuery: How to get selected radio button value?

For radio buttons use the following script:

var myRadio = $('input[name=meme_wall_share]');
var checkedValue = myRadio.filter(':checked').val();

Ansible playbook shell output

Expanding on what leucos said in his answer, you can also print information with Ansible's humble debug module:

- hosts: all
  gather_facts: no
  tasks:
    - shell: ps -eo pcpu,user,args | sort -r -k1 | head -n5
      register: ps

    # Print the shell task's stdout.
    - debug: msg={{ ps.stdout }}

    # Print all contents of the shell task's output.
    - debug: var=ps

How to split a delimited string in Ruby and convert it to an array?

"1,2,3,4".split(",") as strings

"1,2,3,4".split(",").map { |s| s.to_i } as integers

Are there any naming convention guidelines for REST APIs?

I would say that it's preferable to use as few special characters as possible in REST URLs. One of the benefits of REST is that it makes the "interface" for a service easy to read. Camel case or Pascal case is probably good for the resource names (Users or users). I don't think there are really any hard standards around REST.

Also, I think Gandalf is right, it's usually cleaner in REST to not use query string parameters, but instead create paths that define which resources you want to deal with.

http://api.example.com/HelloWorld/Users/12345/Order/3/etc

How to group by week in MySQL?

Figured it out... it's a little cumbersome, but here it is.

FROM_DAYS(TO_DAYS(TIMESTAMP) -MOD(TO_DAYS(TIMESTAMP) -1, 7))

And, if your business rules say your weeks start on Mondays, change the -1 to -2.


Edit

Years have gone by and I've finally gotten around to writing this up. http://www.plumislandmedia.net/mysql/sql-reporting-time-intervals/

Google Colab: how to read data from my google drive?

Edit: As of February, 2020, there's now a first-class UI for automatically mounting Drive.

First, open the file browser on the left hand side. It will show a 'Mount Drive' button. Once clicked, you'll see a permissions prompt to mount Drive, and afterwards your Drive files will be present with no setup when you return to the notebook. The completed flow looks like so:

Drive auto mount example

The original answer follows, below. (This will also still work for shared notebooks.)

You can mount your Google Drive files by running the following code snippet:

from google.colab import drive
drive.mount('/content/drive')

Then, you can interact with your Drive files in the file browser side panel or using command-line utilities.

Here's an example notebook

Is there a "do ... until" in Python?

No there isn't. Instead use a while loop such as:

while 1:
 ...statements...
  if cond:
    break

Connect HTML page with SQL server using javascript

JavaScript is a client-side language and your MySQL database is going to be running on a server.

So you have to rename your file to index.php for example (.php is important) so you can use php code for that. It is not very difficult, but not directly possible with html.

(Somehow you can tell your server to let the html files behave like php files, but this is not the best solution.)

So after you renamed your file, go to the very top, before <html> or <!DOCTYPE html> and type:

<?php
    if($_SERVER['REQUEST_METHOD'] == 'POST') {
        /*Creating variables*/
        $name = $_POST["name"];
        $address = $_POST["address"];
        $age = $_POST["age"];


        $dbhost = "localhost"; /*most of the time it's localhost*/
        $username = "yourusername";
        $password = "yourpassword";
        $dbname = "mydatabase";

        $mysql = mysqli_connect($dbhost, $username, $password, $dbname); //It connects
        $query = "INSERT INTO yourtable (name,address,age) VALUES $name, $address, $age";
        mysqli_query($mysql, $query);
    }
?>
<!DOCTYPE html>
<html>
<head>.......
....
    <form method="post">
        <input name="name" type="text"/>
        <input name="address" type="text"/>
        <input name="age" type="text"/>
    </form>
....

Vertical Align Center in Bootstrap 4

I did it this way with Bootstrap 4.3.1:

<div class="d-flex vh-100">
  <div class="d-flex w-100 justify-content-center align-self-center">
    I'm in the middle
  </div>
</div>

Filtering a spark dataframe based on date

I find the most readable way to express this is using a sql expression:

df.filter("my_date < date'2015-01-01'")

we can verify this works correctly by looking at the physical plan from .explain()

+- *(1) Filter (isnotnull(my_date#22) && (my_date#22 < 16436))

Plain Old CLR Object vs Data Transfer Object

It's probably redundant for me to contribute since I already stated my position in my blog article, but the final paragraph of that article kind of sums things up:

So, in conclusion, learn to love the POCO, and make sure you don’t spread any misinformation about it being the same thing as a DTO. DTOs are simple data containers used for moving data between the layers of an application. POCOs are full fledged business objects with the one requirement that they are Persistence Ignorant (no get or save methods). Lastly, if you haven’t checked out Jimmy Nilsson’s book yet, pick it up from your local university stacks. It has examples in C# and it’s a great read.

BTW, Patrick I read the POCO as a Lifestyle article, and I completely agree, that is a fantastic article. It's actually a section from the Jimmy Nilsson book that I recommended. I had no idea that it was available online. His book really is the best source of information I've found on POCO / DTO / Repository / and other DDD development practices.

How to create a link to another PHP page

Just try like this:

HTML in PHP :

$link_address1 = 'index.php';
echo "<a href='".$link_address1."'>Index Page</a>";

$link_address2 = 'page2.php';
echo "<a href='".$link_address2."'>Page 2</a>";

Easiest way

$link_address1 = 'index.php';
echo "<a href='$link_address1'>Index Page</a>";

$link_address2 = 'page2.php';
echo "<a href='$link_address2'>Page 2</a>";

How to set root password to null

For MySQL 8.0 just:

SET PASSWORD FOR 'root'@'localhost' = '';

Can you Run Xcode in Linux?

Nope, you've heard of MonoTouch which is a .NET/mono environment for iPhone development. But you still need a Mac and the official iPhone SDK. And the emulator is the official apple one, this acts as a separate IDE and allows you to not have to code in Objective C, rather you code in c#

It's an interesting project to say the least....

EDIT: apparently, you can distribute on the app store now, early on that was a no go....

How to format a floating number to fixed width in Python

This will print 76.66:

print("Number: ", f"{76.663254: .2f}")

Converting List<Integer> to List<String>

As far as I know, iterate and instantiate is the only way to do this. Something like (for others potential help, since I'm sure you know how to do this):

List<Integer> oldList = ...
/* Specify the size of the list up front to prevent resizing. */
List<String> newList = new ArrayList<>(oldList.size());
for (Integer myInt : oldList) { 
  newList.add(String.valueOf(myInt)); 
}

Flutter - Layout a Grid

A simple example loading images into the tiles.

import 'package:flutter/material.dart';

void main() {
  runApp( MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(

      color: Colors.white30,
      child: GridView.count(
          crossAxisCount: 4,
          childAspectRatio: 1.0,
          padding: const EdgeInsets.all(4.0),
          mainAxisSpacing: 4.0,
          crossAxisSpacing: 4.0,
          children: <String>[
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
            'http://www.for-example.org/img/main/forexamplelogo.png',
          ].map((String url) {
            return GridTile(
                child: Image.network(url, fit: BoxFit.cover));
          }).toList()),
    );
  }
}

The Flutter Gallery app contains a real world example, which can be found here.

enter image description here

How get total sum from input box values using Javascript?

I need to sum the span elements so I edited Akhil Sekharan's answer below.

var arr = document.querySelectorAll('span[id^="score"]');
var total=0;
    for(var i=0;i<arr.length;i++){
        if(parseInt(arr[i].innerHTML))
            total+= parseInt(arr[i].innerHTML);
    }
console.log(total)

You can change the elements with other elements link will guide you with editing.

https://www.w3.org/TR/css3-selectors/#attribute-substrings

ERROR 1115 (42000): Unknown character set: 'utf8mb4'

You can try:

Open sql file by text editor find and replace all

utf8mb4 to utf8

Import again.

How do I compare two columns for equality in SQL Server?

I'd go with the CASE WHEN also.

Depending on what you actually want to do, there may be other options though, like using an outer join or whatever, but that doesn't seem to be what you need in this case.

Embed Youtube video inside an Android app

Embedding the YouTube player in Android is very simple & it hardly takes you 10 minutes,

1) Enable YouTube API from Google API console
2) Download YouTube player Jar file
3) Start using it in Your app

Here are the detailed steps http://www.feelzdroid.com/2017/01/embed-youtube-video-player-android-app-example.html.

Just refer it & if you face any problem, let me know, ill help you

TypeError: object of type 'int' has no len() error assistance needed

Abstract:

The reason why you are getting this error message is because you are trying to call a method on an int type of a variable. This would work if would have called len() function on a list type of a variable. Let's examin the two cases:

Fail:

num = 10

print(len(num))

The above will produce an error similar to yours due to calling len() function on an int type of a variable;

Success:

data = [0, 4, 8, 9, 12]

print(len(data))

The above will work since you are calling a function on a list type of a variable;

How to get content body from a httpclient call?

The way you are using await/async is poor at best, and it makes it hard to follow. You are mixing await with Task'1.Result, which is just confusing. However, it looks like you are looking at a final task result, rather than the contents.

I've rewritten your function and function call, which should fix your issue:

async Task<string> GetResponseString(string text)
{
    var httpClient = new HttpClient();

    var parameters = new Dictionary<string, string>();
    parameters["text"] = text;

    var response = await httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));
    var contents = await response.Content.ReadAsStringAsync();

    return contents;
}

And your final function call:

Task<string> result = GetResponseString(text);
var finalResult = result.Result;

Or even better:

var finalResult = await GetResponseString(text);

Selenium WebDriver How to Resolve Stale Element Reference Exception?

When a Stale Element Exception occurs!!

Stale element exception can happen when the libraries supporting those textboxes/ buttons/ links has changed which means the elements are same but the reference has now changed in the website without affecting the locators. Thus the reference which we stored in our cache including the library reference has now become old or stale because the page has been refreshed with updated libraries.

for(int j=0; j<5;j++)
try {
    WebElement elementName=driver.findElement(By.name(“createForm:dateInput_input”));
    break;
} catch(StaleElementReferenceException e){
e.toString();
System.out.println(“Stale element error, trying ::  ” + e.getMessage());
}
elementName.sendKeys(“20/06/2018”);

Converting Epoch time into the datetime

Try this:

>>> import time
>>> time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(1347517119))
'2012-09-12 23:18:39'

Also in MySQL, you can FROM_UNIXTIME like:

INSERT INTO tblname VALUES (FROM_UNIXTIME(1347517119))

For your 2nd question, it is probably because getbbb_class.end_time is a string. You can convert it to numeric like: float(getbbb_class.end_time)

throwing an exception in objective-c/cocoa

Since ObjC 2.0, Objective-C exceptions are no longer a wrapper for C's setjmp() longjmp(), and are compatible with C++ exception, the @try is "free of charge", but throwing and catching exceptions is way more expensive.

Anyway, assertions (using NSAssert and NSCAssert macro family) throw NSException, and that sane to use them as Ries states.

Fitting empirical distribution to theoretical ones with Scipy (Python)?

It sounds like probability density estimation problem to me.

from scipy.stats import gaussian_kde
occurences = [0,0,0,0,..,1,1,1,1,...,2,2,2,2,...,47]
values = range(0,48)
kde = gaussian_kde(map(float, occurences))
p = kde(values)
p = p/sum(p)
print "P(x>=1) = %f" % sum(p[1:])

Also see http://jpktd.blogspot.com/2009/03/using-gaussian-kernel-density.html.

Updating to latest version of CocoaPods?

You can solve this problem by these Commands:

First:

sudo gem install cocoapods

Desp: type user mac password now your cocoapods will be replace with a stable version.

You can find out where the CocoaPods gem is installed with:

gem which cocoapods

if you have cloned the repo then type this command:

pod repo update

close your xcode and run this command

Pod install

Turning multi-line string into single comma-separated

Yet another AWK solution

Run

awk '{printf "%s", $c; while(getline){printf "%s%s", sep, $c}}' c=2 sep=','

to use the 2nd column to form the list separated by commas. Give the input as usual in standard input or as a file name argument.

Is it possible for UIStackView to scroll?

If you have a constraint to center the Stack View vertically inside the scroll view, just remove it.

Check date between two other dates spring data jpa

I did use following solution to this:

findAllByStartDateLessThanEqualAndEndDateGreaterThanEqual(OffsetDateTime endDate, OffsetDateTime startDate);

How do I convert a pandas Series or index to a Numpy array?

pandas >= 0.24

Deprecate your usage of .values in favour of these methods!

From v0.24.0 onwards, we will have two brand spanking new, preferred methods for obtaining NumPy arrays from Index, Series, and DataFrame objects: they are to_numpy(), and .array. Regarding usage, the docs mention:

We haven’t removed or deprecated Series.values or DataFrame.values, but we highly recommend and using .array or .to_numpy() instead.

See this section of the v0.24.0 release notes for more information.


to_numpy() Method

df.index.to_numpy()
# array(['a', 'b'], dtype=object)

df['A'].to_numpy()
#  array([1, 4])

By default, a view is returned. Any modifications made will affect the original.

v = df.index.to_numpy()
v[0] = -1

df
    A  B
-1  1  2
b   4  5

If you need a copy instead, use to_numpy(copy=True);

v = df.index.to_numpy(copy=True)
v[-1] = -123

df
   A  B
a  1  2
b  4  5

Note that this function also works for DataFrames (while .array does not).


array Attribute
This attribute returns an ExtensionArray object that backs the Index/Series.

pd.__version__
# '0.24.0rc1'

# Setup.
df = pd.DataFrame([[1, 2], [4, 5]], columns=['A', 'B'], index=['a', 'b'])
df

   A  B
a  1  2
b  4  5

df.index.array    
# <PandasArray>
# ['a', 'b']
# Length: 2, dtype: object

df['A'].array
# <PandasArray>
# [1, 4]
# Length: 2, dtype: int64

From here, it is possible to get a list using list:

list(df.index.array)
# ['a', 'b']

list(df['A'].array)
# [1, 4]

or, just directly call .tolist():

df.index.tolist()
# ['a', 'b']

df['A'].tolist()
# [1, 4]

Regarding what is returned, the docs mention,

For Series and Indexes backed by normal NumPy arrays, Series.array will return a new arrays.PandasArray, which is a thin (no-copy) wrapper around a numpy.ndarray. arrays.PandasArray isn’t especially useful on its own, but it does provide the same interface as any extension array defined in pandas or by a third-party library.

So, to summarise, .array will return either

  1. The existing ExtensionArray backing the Index/Series, or
  2. If there is a NumPy array backing the series, a new ExtensionArray object is created as a thin wrapper over the underlying array.

Rationale for adding TWO new methods
These functions were added as a result of discussions under two GitHub issues GH19954 and GH23623.

Specifically, the docs mention the rationale:

[...] with .values it was unclear whether the returned value would be the actual array, some transformation of it, or one of pandas custom arrays (like Categorical). For example, with PeriodIndex, .values generates a new ndarray of period objects each time. [...]

These two functions aim to improve the consistency of the API, which is a major step in the right direction.

Lastly, .values will not be deprecated in the current version, but I expect this may happen at some point in the future, so I would urge users to migrate towards the newer API, as soon as you can.

Rotating a Vector in 3D Space

If you want to rotate a vector you should construct what is known as a rotation matrix.

Rotation in 2D

Say you want to rotate a vector or a point by ?, then trigonometry states that the new coordinates are

    x' = x cos ? - y sin ?
    y' = x sin ? + y cos ?

To demo this, let's take the cardinal axes X and Y; when we rotate the X-axis 90° counter-clockwise, we should end up with the X-axis transformed into Y-axis. Consider

    Unit vector along X axis = <1, 0>
    x' = 1 cos 90 - 0 sin 90 = 0
    y' = 1 sin 90 + 0 cos 90 = 1
    New coordinates of the vector, <x', y'> = <0, 1>  ?  Y-axis

When you understand this, creating a matrix to do this becomes simple. A matrix is just a mathematical tool to perform this in a comfortable, generalized manner so that various transformations like rotation, scale and translation (moving) can be combined and performed in a single step, using one common method. From linear algebra, to rotate a point or vector in 2D, the matrix to be built is

    |cos ?   -sin ?| |x| = |x cos ? - y sin ?| = |x'|
    |sin ?    cos ?| |y|   |x sin ? + y cos ?|   |y'|

Rotation in 3D

That works in 2D, while in 3D we need to take in to account the third axis. Rotating a vector around the origin (a point) in 2D simply means rotating it around the Z-axis (a line) in 3D; since we're rotating around Z-axis, its coordinate should be kept constant i.e. 0° (rotation happens on the XY plane in 3D). In 3D rotating around the Z-axis would be

    |cos ?   -sin ?   0| |x|   |x cos ? - y sin ?|   |x'|
    |sin ?    cos ?   0| |y| = |x sin ? + y cos ?| = |y'|
    |  0       0      1| |z|   |        z        |   |z'|

around the Y-axis would be

    | cos ?    0   sin ?| |x|   | x cos ? + z sin ?|   |x'|
    |   0      1       0| |y| = |         y        | = |y'|
    |-sin ?    0   cos ?| |z|   |-x sin ? + z cos ?|   |z'|

around the X-axis would be

    |1     0           0| |x|   |        x        |   |x'|
    |0   cos ?    -sin ?| |y| = |y cos ? - z sin ?| = |y'|
    |0   sin ?     cos ?| |z|   |y sin ? + z cos ?|   |z'|

Note 1: axis around which rotation is done has no sine or cosine elements in the matrix.

Note 2: This method of performing rotations follows the Euler angle rotation system, which is simple to teach and easy to grasp. This works perfectly fine for 2D and for simple 3D cases; but when rotation needs to be performed around all three axes at the same time then Euler angles may not be sufficient due to an inherent deficiency in this system which manifests itself as Gimbal lock. People resort to Quaternions in such situations, which is more advanced than this but doesn't suffer from Gimbal locks when used correctly.

I hope this clarifies basic rotation.

Rotation not Revolution

The aforementioned matrices rotate an object at a distance r = v(x² + y²) from the origin along a circle of radius r; lookup polar coordinates to know why. This rotation will be with respect to the world space origin a.k.a revolution. Usually we need to rotate an object around its own frame/pivot and not around the world's i.e. local origin. This can also be seen as a special case where r = 0. Since not all objects are at the world origin, simply rotating using these matrices will not give the desired result of rotating around the object's own frame. You'd first translate (move) the object to world origin (so that the object's origin would align with the world's, thereby making r = 0), perform the rotation with one (or more) of these matrices and then translate it back again to its previous location. The order in which the transforms are applied matters. Combining multiple transforms together is called concatenation or composition.

Composition

I urge you to read about linear and affine transformations and their composition to perform multiple transformations in one shot, before playing with transformations in code. Without understanding the basic maths behind it, debugging transformations would be a nightmare. I found this lecture video to be a very good resource. Another resource is this tutorial on transformations that aims to be intuitive and illustrates the ideas with animation (caveat: authored by me!).

Rotation around Arbitrary Vector

A product of the aforementioned matrices should be enough if you only need rotations around cardinal axes (X, Y or Z) like in the question posted. However, in many situations you might want to rotate around an arbitrary axis/vector. The Rodrigues' formula (a.k.a. axis-angle formula) is a commonly prescribed solution to this problem. However, resort to it only if you’re stuck with just vectors and matrices. If you're using Quaternions, just build a quaternion with the required vector and angle. Quaternions are a superior alternative for storing and manipulating 3D rotations; it's compact and fast e.g. concatenating two rotations in axis-angle representation is fairly expensive, moderate with matrices but cheap in quaternions. Usually all rotation manipulations are done with quaternions and as the last step converted to matrices when uploading to the rendering pipeline. See Understanding Quaternions for a decent primer on quaternions.

SQL query with avg and group by

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

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

std::cin input with spaces?

Use :

getline(cin, input);

the function can be found in

#include <string>

How to get controls in WPF to fill available space?

Well, I figured it out myself, right after posting, which is the most embarassing way. :)

It seems every member of a StackPanel will simply fill its minimum requested size.

In the DockPanel, I had docked things in the wrong order. If the TextBox or ListBox is the only docked item without an alignment, or if they are the last added, they WILL fill the remaining space as wanted.

I would love to see a more elegant method of handling this, but it will do.

How to run Spyder in virtual environment?

I follow one of the advice above and indeed it works. In summary while you download Anaconda on Ubuntu using the advice given above can help you to 'create' environments. The default when you download Spyder in my case is: (base) smith@ubuntu ~$. After you create the environment, i.e. fenics and activate it with $ conda activate fenics the prompt change to (fenics) smith@ubuntu ~$. Then you launch Spyder from this prompt, i.e $ spyder and your system open the Spyder IDE, and you can write fenics code on it. Remember every time you open a terminal your system open the default prompt. You have to activate your environment where your package is and the prompt change to it i.e. (fenics).

Convert Data URI to File then append to FormData

Firefox has canvas.toBlob() and canvas.mozGetAsFile() methods.

But other browsers do not.

We can get dataurl from canvas and then convert dataurl to blob object.

Here is my dataURLtoBlob() function. It's very short.

function dataURLtoBlob(dataurl) {
    var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
    while(n--){
        u8arr[n] = bstr.charCodeAt(n);
    }
    return new Blob([u8arr], {type:mime});
}

Use this function with FormData to handle your canvas or dataurl.

For example:

var dataurl = canvas.toDataURL('image/jpeg',0.8);
var blob = dataURLtoBlob(dataurl);
var fd = new FormData();
fd.append("myFile", blob, "thumb.jpg");

Also, you can create a HTMLCanvasElement.prototype.toBlob method for non gecko engine browser.

if(!HTMLCanvasElement.prototype.toBlob){
    HTMLCanvasElement.prototype.toBlob = function(callback, type, encoderOptions){
        var dataurl = this.toDataURL(type, encoderOptions);
        var bstr = atob(dataurl.split(',')[1]), n = bstr.length, u8arr = new Uint8Array(n);
        while(n--){
            u8arr[n] = bstr.charCodeAt(n);
        }
        var blob = new Blob([u8arr], {type: type});
        callback.call(this, blob);
    };
}

Now canvas.toBlob() works for all modern browsers not only Firefox. For example:

canvas.toBlob(
    function(blob){
        var fd = new FormData();
        fd.append("myFile", blob, "thumb.jpg");
        //continue do something...
    },
    'image/jpeg',
    0.8
);

Parse JSON object with string and value only

My pseudocode example will be as follows:

JSONArray jsonArray = "[{id:\"1\", name:\"sql\"},{id:\"2\",name:\"android\"},{id:\"3\",name:\"mvc\"}]";
JSON newJson = new JSON();

for (each json in jsonArray) {
    String id = json.get("id");
    String name = json.get("name");

    newJson.put(id, name);
}

return newJson;

Check if any type of files exist in a directory using BATCH script

For files in a directory, you can use things like:

if exist *.csv echo "csv file found"

or

if not exist *.csv goto nofile

Why is list initialization (using curly braces) better than the alternatives?

There are MANY reasons to use brace initialization, but you should be aware that the initializer_list<> constructor is preferred to the other constructors, the exception being the default-constructor. This leads to problems with constructors and templates where the type T constructor can be either an initializer list or a plain old ctor.

struct Foo {
    Foo() {}

    Foo(std::initializer_list<Foo>) {
        std::cout << "initializer list" << std::endl;
    }

    Foo(const Foo&) {
        std::cout << "copy ctor" << std::endl;
    }
};

int main() {
    Foo a;
    Foo b(a); // copy ctor
    Foo c{a}; // copy ctor (init. list element) + initializer list!!!
}

Assuming you don't encounter such classes there is little reason not to use the intializer list.

Javascript Append Child AFTER Element

If you are looking for a plain JS solution, then you just use insertBefore() against nextSibling.

Something like:

parentGuest.parentNode.insertBefore(childGuest, parentGuest.nextSibling);

Note that default value of nextSibling is null, so, you don't need to do anything special for that.

Update: You don't even need the if checking presence of parentGuest.nextSibling like the currently accepted answer does, because if there's no next sibling, it will return null, and passing null to the 2nd argument of insertBefore() means: append at the end.

Reference:

.

IF you are using jQuery (ignore otherwise, I have stated plain JS answer above), you can leverage the convenient after() method:

$("#one").after("<li id='two'>");

Reference:

Is there a CSS parent selector?

Just an idea for horizontal menu...

Part of HTML

<div class='list'>
  <div class='item'>
    <a>Link</a>
  </div>
  <div class='parent-background'></div>
  <!-- submenu takes this place -->
</div>

Part of CSS

/* Hide parent backgrounds... */
.parent-background {
  display: none; }

/* ... and show it when hover on children */
.item:hover + .parent-background {
  display: block;
  position: absolute;
  z-index: 10;
  top: 0;
  width: 100%; }

Updated demo and the rest of code

Another example how to use it with text-inputs - select parent fieldset

Bluetooth pairing without user confirmation

This need is exactly why createInsecureRfcommSocketToServiceRecord() was added to BluetoothDevice starting in Android 2.3.3 (API Level 10) (SDK Docs)...before that there was no SDK support for this. It was designed to allow Android to connect to devices without user interfaces for entering a PIN code (like an embedded device), but it just as usable for setting up a connection between two devices without user PIN entry.

The corollary method listenUsingInsecureRfcommWithServiceRecord() in BluetoothAdapter is used to accept these types of connections. It's not a security breach because the methods must be used as a pair. You cannot use this to simply attempt to pair with any old Bluetooth device.

You can also do short range communications over NFC, but that hardware is less prominent on Android devices. Definitely pick one, and don't try to create a solution that uses both.

Hope that Helps!

P.S. There are also ways to do this on many devices prior to 2.3 using reflection, because the code did exist...but I wouldn't necessarily recommend this for mass-distributed production applications. See this StackOverflow.

Export multiple classes in ES6 modules

For exporting the instances of the classes you can use this syntax:

// export index.js
const Foo = require('./my/module/foo');
const Bar = require('./my/module/bar');

module.exports = {
    Foo : new Foo(),
    Bar : new Bar()
};

// import and run method
const {Foo,Bar} = require('module_name');
Foo.test();

How to stretch children to fill cross-axis?

  • The children of a row-flexbox container automatically fill the container's vertical space.

  • Specify flex: 1; for a child if you want it to fill the remaining horizontal space:

_x000D_
_x000D_
.wrapper {_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  align-items: stretch;_x000D_
  width: 100%;_x000D_
  height: 5em;_x000D_
  background: #ccc;_x000D_
}_x000D_
.wrapper > .left_x000D_
{_x000D_
  background: #fcc;_x000D_
}_x000D_
.wrapper > .right_x000D_
{_x000D_
  background: #ccf;_x000D_
  flex: 1; _x000D_
}
_x000D_
<div class="wrapper">_x000D_
  <div class="left">Left</div>_x000D_
  <div class="right">Right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

  • Specify flex: 1; for both children if you want them to fill equal amounts of the horizontal space:

_x000D_
_x000D_
.wrapper {_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  align-items: stretch;_x000D_
  width: 100%;_x000D_
  height: 5em;_x000D_
  background: #ccc;_x000D_
}_x000D_
.wrapper > div _x000D_
{_x000D_
  flex: 1; _x000D_
}_x000D_
.wrapper > .left_x000D_
{_x000D_
  background: #fcc;_x000D_
}_x000D_
.wrapper > .right_x000D_
{_x000D_
  background: #ccf;_x000D_
}
_x000D_
<div class="wrapper">_x000D_
  <div class="left">Left</div>_x000D_
  <div class="right">Right</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Convert blob URL to normal URL

Found this answer here and wanted to reference it as it appear much cleaner than the accepted answer:

function blobToDataURL(blob, callback) {
  var fileReader = new FileReader();
  fileReader.onload = function(e) {callback(e.target.result);}
  fileReader.readAsDataURL(blob);
}

bash string equality

There's no difference, == is a synonym for = (for the C/C++ people, I assume). See here, for example.

You could double-check just to be really sure or just for your interest by looking at the bash source code, should be somewhere in the parsing code there, but I couldn't find it straightaway.

How to convert a Drawable to a Bitmap?

1) Drawable to Bitmap :

Bitmap mIcon = BitmapFactory.decodeResource(context.getResources(),R.drawable.icon);
// mImageView.setImageBitmap(mIcon);

2) Bitmap to Drawable :

Drawable mDrawable = new BitmapDrawable(getResources(), bitmap);
// mImageView.setDrawable(mDrawable);

GCM with PHP (Google Cloud Messaging)

It's easy to do. The cURL code that's on the page that Elad Nava has put here works. Elad has commented about the error he's receiving.

String describing an error that occurred while processing the message for that recipient. The possible values are the same as documented in the above table, plus "Unavailable" (meaning GCM servers were busy and could not process the message for that particular recipient, so it could be retried).

I've got a service set up already that seems to be working (ish), and so far all I've had back are unavailable returns from Google. More than likely this will change soon.

To answer the question, use PHP, make sure the Zend Framework is in your include path, and use this code:

<?php
    ini_set('display_errors',1);
    include"Zend/Loader/Autoloader.php";
    Zend_Loader_Autoloader::getInstance();

    $url = 'https://android.googleapis.com/gcm/send';
    $serverApiKey = "YOUR API KEY AS GENERATED IN API CONSOLE";
    $reg = "DEVICE REGISTRATION ID";

    $data = array(
            'registration_ids' => array($reg),
            'data' => array('yourname' => 'Joe Bloggs')
    );

    print(json_encode($data));

    $client = new Zend_Http_Client($url);
    $client->setMethod('POST');
    $client->setHeaders(array("Content-Type" => "application/json", "Authorization" => "key=" . $serverApiKey));
    $client->setRawData(json_encode($data));
    $request = $client->request('POST');
    $body = $request->getBody();
    $headers = $request->getHeaders();
    print("<xmp>");
    var_dump($body);
    var_dump($headers);

And there we have it. A working (it will work soon) example of using Googles new GCM in Zend Framework PHP.

Create a batch file to run an .exe with an additional parameter

Found another solution for the same. It will be more helpful.

START C:\"Program Files (x86)"\Test\"Test Automation"\finger.exe ConfigFile="C:\Users\PCName\Desktop\Automation\Documents\Validation_ZoneWise_Default.finger.Config"

finger.exe is a parent program that is calling config solution. Note: if your path folder name consists of spaces, then do not forget to add "".

How to have a transparent ImageButton: Android

The best way is using the transparent color code

android:background="#00000000"

use the color code #00000000 for making any thing transparent

Convert data.frame columns from factors to characters

If you want a new data frame bobc where every factor vector in bobf is converted to a character vector, try this:

bobc <- rapply(bobf, as.character, classes="factor", how="replace")

If you then want to convert it back, you can create a logical vector of which columns are factors, and use that to selectively apply factor

f <- sapply(bobf, class) == "factor"
bobc[,f] <- lapply(bobc[,f], factor)

sql delete statement where date is greater than 30 days

To delete records from a table that have a datetime value in Date_column older than 30 days use this query:

USE Database_name;
DELETE FROM Table_name
WHERE Date_column < GETDATE() - 30

...or this:

USE Database_name;
DELETE FROM Table_name
WHERE Date_column < DATEADD(dd,-30,GETDATE())

To delete records from a table that have a datetime value in Date_column older than 12 hours:

USE Database_name;
DELETE FROM Table_name
WHERE Date_column < DATEADD(hh,-12,GETDATE())

To delete records from a table that have a datetime value in Date_column older than 15 minutes:

USE Database_name;
DELETE FROM Table_name
WHERE Date_column < DATEADD(mi,-15,GETDATE())

From: http://zarez.net/?p=542

How to check for null/empty/whitespace values with a single test?

This phpMyAdmin query is returning those rows, that are NOT null or empty or just whitespaces:

SELECT * FROM `table_name` WHERE NOT ((`column_name` IS NULL) OR (TRIM(`column_name`) LIKE ''))

if you want to select rows that are null/empty/just whitespaces just remove NOT.

Facebook Open Graph Error - Inferred Property

Are those tags on 'http://www.mywebaddress.com'?

Bear in mind the linter will follow the og:url tag as this tag should point to the canonical URL of the piece of content - so if you have a page, e.g. 'http://mywebaddress.com/article1' with an og:url tag pointing to 'http://mywebaddress.com', Facebook will go there and read the tags there also.

Failing that, the most common reason i've seen for seemingly correct tags not being detected by the linter is user-agent detection returning different content to Facebook's crawler than the content you're seeing when you manually check

Is it possible to focus on a <div> using JavaScript focus() function?

You can use tabindex

<div tabindex="-1"  id="tries"></div>

The tabindex value can allow for some interesting behaviour.

  • If given a value of "-1", the element can't be tabbed to but focus can be given to the element programmatically (using element.focus()).
  • If given a value of 0, the element can be focused via the keyboard and falls into the tabbing flow of the document. Values greater than 0 create a priority level with 1 being the most important.

Join a list of items with different types as string in Python

map function in python can be used. It takes two arguments. First argument is the function which has to be used for each element of the list. Second argument is the iterable.

a = [1, 2, 3]   
map(str, a)  
['1', '2', '3']

After converting the list into string you can use simple join function to combine list into a single string

a = map(str, a)    
''.join(a)      
'123'

How do I delete a local repository in git?

To piggyback on rkj's answer, to avoid endless prompts (and force the command recursively), enter the following into the command line, within the project folder:

$ rm -rf .git

Or to delete .gitignore and .gitmodules if any (via @aragaer):

$ rm -rf .git*

Then from the same ex-repository folder, to see if hidden folder .git is still there:

$ ls -lah

If it's not, then congratulations, you've deleted your local git repo, but not a remote one if you had it. You can delete GitHub repo on their site (github.com).

To view hidden folders in Finder (Mac OS X) execute these two commands in your terminal window:

defaults write com.apple.finder AppleShowAllFiles TRUE
killall Finder

Source: http://lifehacker.com/188892/show-hidden-files-in-finder.

Is there a way to add/remove several classes in one single instruction with classList?

To add class to a element

document.querySelector(elem).className+=' first second third';

UPDATE:

Remove a class

document.querySelector(elem).className=document.querySelector(elem).className.split(class_to_be_removed).join(" ");

Best way to integrate Python and JavaScript?

Many of these projects mentioned above are dead or dying, lacking activity and interest from author side. Interesting to follow how this area develops.

For the record, in era of plugin based implementations, KDE camp had an attempt to solve this with plugin and non-language specific way and created the Kross https://en.wikipedia.org/wiki/Kross_(software) - in my understanding it never took off even inside the community itself.

During this chicken and egg -problem time, javascript-based implementions are definately way to go. Maybe in the future we seee pure and clean, full Python support natively in browsers.

How to get parameter on Angular2 route in Angular way?

As of Angular 6+, this is handled slightly differently than in previous versions. As @BeetleJuice mentions in the answer above, paramMap is new interface for getting route params, but the execution is a bit different in more recent versions of Angular. Assuming this is in a component:

private _entityId: number;

constructor(private _route: ActivatedRoute) {
    // ...
}

ngOnInit() {
    // For a static snapshot of the route...
    this._entityId = this._route.snapshot.paramMap.get('id');

    // For subscribing to the observable paramMap...
    this._route.paramMap.pipe(
        switchMap((params: ParamMap) => this._entityId = params.get('id'))
    );

    // Or as an alternative, with slightly different execution...
    this._route.paramMap.subscribe((params: ParamMap) =>  {
        this._entityId = params.get('id');
    });
}

I prefer to use both because then on direct page load I can get the ID param, and also if navigating between related entities the subscription will update properly.

Source in Angular Docs

UPDATE if exists else INSERT in SQL Server 2008

Many people will suggest you use MERGE, but I caution you against it. By default, it doesn't protect you from concurrency and race conditions any more than multiple statements, but it does introduce other dangers:

http://www.mssqltips.com/sqlservertip/3074/use-caution-with-sql-servers-merge-statement/

Even with this "simpler" syntax available, I still prefer this approach (error handling omitted for brevity):

SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
BEGIN TRANSACTION;
UPDATE dbo.table SET ... WHERE PK = @PK;
IF @@ROWCOUNT = 0
BEGIN
  INSERT dbo.table(PK, ...) SELECT @PK, ...;
END
COMMIT TRANSACTION;

A lot of folks will suggest this way:

SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
BEGIN TRANSACTION;
IF EXISTS (SELECT 1 FROM dbo.table WHERE PK = @PK)
BEGIN
  UPDATE ...
END
ELSE
BEGIN
  INSERT ...
END
COMMIT TRANSACTION;

But all this accomplishes is ensuring you may need to read the table twice to locate the row(s) to be updated. In the first sample, you will only ever need to locate the row(s) once. (In both cases, if no rows are found from the initial read, an insert occurs.)

Others will suggest this way:

BEGIN TRY
  INSERT ...
END TRY
BEGIN CATCH
  IF ERROR_NUMBER() = 2627
    UPDATE ...
END CATCH

However, this is problematic if for no other reason than letting SQL Server catch exceptions that you could have prevented in the first place is much more expensive, except in the rare scenario where almost every insert fails. I prove as much here:

Not sure what you think you gain by having a single statement; I don't think you gain anything. MERGE is a single statement but it still has to really perform multiple operations anyway - even though it makes you think it doesn't.

How do you make an anchor link non-clickable or disabled?

Add a css class:

.disable_a_href{
    pointer-events: none;
}

Add this jquery:

$("#ThisLink").addClass("disable_a_href"); 

How to use @Nullable and @Nonnull annotations more effectively?

Short answer: I guess these annotations are only useful for your IDE to warn you of potentially null pointer errors.

As said in the "Clean Code" book, you should check your public method's parameters and also avoid checking invariants.

Another good tip is never returning null values, but using Null Object Pattern instead.

Two HTML tables side by side, centered on the page

Give your inner div a width.

EXAMPLE

Change your CSS:

<style>
#outer { text-align: center; }
#inner { text-align: left; margin: 0 auto; }
.t { float: left; }
table { border: 1px solid black; }
#clearit { clear: left; }
</style>

To this:

<style>
#outer { text-align: center; }
#inner { text-align: left; margin: 0 auto; width:500px }
.t { float: left; }
table { border: 1px solid black; }
#clearit { clear: left; }
</style>

How to validate numeric values which may contain dots or commas?

\d{1,2}[\,\.]{1}\d{1,2}

EDIT: update to meet the new requirements (comments) ;)
EDIT: remove unnecesary qtfier as per Bryan

^[0-9]{1,2}([,.][0-9]{1,2})?$

How to initialize a vector in C++

You can also do like this:

template <typename T>
class make_vector {
public:
  typedef make_vector<T> my_type;
  my_type& operator<< (const T& val) {
    data_.push_back(val);
    return *this;
  }
  operator std::vector<T>() const {
    return data_;
  }
private:
  std::vector<T> data_;
};

And use it like this:

std::vector<int> v = make_vector<int>() << 1 << 2 << 3;

check if a string matches an IP address pattern in python?

You can make it a little faster by compiling it:

expression = re.compile('^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$')
for st in strs:
    if expression.match(st):
       print 'IP!'

How do I get the output of a shell command executed using into a variable from Jenkinsfile (groovy)?

this is a sample case, which will make sense I believe!

node('master'){
    stage('stage1'){
    def commit = sh (returnStdout: true, script: '''echo hi
    echo bye | grep -o "e"
    date
    echo lol''').split()


    echo "${commit[-1]} "

    }
}

Format telephone and credit card numbers in AngularJS

You also can check input mask formatter.

This is a directive and it's called ui-mask and also it's a part of angular-ui.utils library.

Here is working: Live example

For the time of writing this post there aren't any examples of using this directive, so I've made a very simple example to demonstrate how this thing works in practice.

How to use PHP OPCache?

With PHP 5.6 on Amazon Linux (should be the same on RedHat or CentOS):

yum install php56-opcache

and then restart apache.

Append integer to beginning of list in Python

>>> a = 5
>>> li = [1, 2, 3]
>>> [a] + li  # Don't use 'list' as variable name.
[5, 1, 2, 3]

pod has unbound PersistentVolumeClaims

You have to define a PersistentVolume providing disc space to be consumed by the PersistentVolumeClaim.

When using storageClass Kubernetes is going to enable "Dynamic Volume Provisioning" which is not working with the local file system.


To solve your issue:

  • Provide a PersistentVolume fulfilling the constraints of the claim (a size >= 100Mi)
  • Remove the storageClass-line from the PersistentVolumeClaim
  • Remove the StorageClass from your cluster

How do these pieces play together?

At creation of the deployment state-description it is usually known which kind (amount, speed, ...) of storage that application will need.
To make a deployment versatile you'd like to avoid a hard dependency on storage. Kubernetes' volume-abstraction allows you to provide and consume storage in a standardized way.

The PersistentVolumeClaim is used to provide a storage-constraint alongside the deployment of an application.

The PersistentVolume offers cluster-wide volume-instances ready to be consumed ("bound"). One PersistentVolume will be bound to one claim. But since multiple instances of that claim may be run on multiple nodes, that volume may be accessed by multiple nodes.

A PersistentVolume without StorageClass is considered to be static.

"Dynamic Volume Provisioning" alongside with a StorageClass allows the cluster to provision PersistentVolumes on demand. In order to make that work, the given storage provider must support provisioning - this allows the cluster to request the provisioning of a "new" PersistentVolume when an unsatisfied PersistentVolumeClaim pops up.


Example PersistentVolume

In order to find how to specify things you're best advised to take a look at the API for your Kubernetes version, so the following example is build from the API-Reference of K8S 1.17:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: ckan-pv-home
  labels:
    type: local
spec:
  capacity:
    storage: 100Mi
  hostPath:
    path: "/mnt/data/ckan"

The PersistentVolumeSpec allows us to define multiple attributes. I chose a hostPath volume which maps a local directory as content for the volume. The capacity allows the resource scheduler to recognize this volume as applicable in terms of resource needs.


Additional Resources:

How to delete an element from an array in C#

You can also convert your array to a list and call remove on the list. You can then convert back to your array.

int[] numbers = {1, 3, 4, 9, 2};
var numbersList = numbers.ToList();
numbersList.Remove(4);

HTTP Content-Type Header and JSON

Content-Type: application/json is just the content header. The content header is just information about the type of returned data, ex::JSON,image(png,jpg,etc..),html.

Keep in mind, that JSON in JavaScript is an array or object. If you want to see all the data, use console.log instead of alert:

alert(response.text); // Will alert "[object Object]" string
console.log(response.text); // Will log all data objects

If you want to alert the original JSON content as a string, then add single quotation marks ('):

echo "'" . json_encode(array('text' => 'omrele')) . "'";
// alert(response.text) will alert {"text":"omrele"}

Do not use double quotes. It will confuse JavaScript, because JSON uses double quotes on each value and key:

echo '<script>var returndata=';
echo '"' . json_encode(array('text' => 'omrele')) . '"';
echo ';</script>';

// It will return the wrong JavaScript code:
<script>var returndata="{"text":"omrele"}";</script>

How to update core-js to core-js@3 dependency?

For ng9 upgraders:

npm i -g core-js@^3

..then:

npm cache clean -f

..followed by:

npm i

How to create PDF files in Python

fpdf is python (too). And often used. See PyPI / pip search. But maybe it was renamed from pyfpdf to fpdf. From features: PNG, GIF and JPG support (including transparency and alpha channel)

IOCTL Linux device driver

The ioctl function is useful for implementing a device driver to set the configuration on the device. e.g. a printer that has configuration options to check and set the font family, font size etc. ioctl could be used to get the current font as well as set the font to a new one. A user application uses ioctl to send a code to a printer telling it to return the current font or to set the font to a new one.

int ioctl(int fd, int request, ...)
  1. fd is file descriptor, the one returned by open;
  2. request is request code. e.g GETFONT will get the current font from the printer, SETFONT will set the font on the printer;
  3. the third argument is void *. Depending on the second argument, the third may or may not be present, e.g. if the second argument is SETFONT, the third argument can be the font name such as "Arial";

int request is not just a macro. A user application is required to generate a request code and the device driver module to determine which configuration on device must be played with. The application sends the request code using ioctl and then uses the request code in the device driver module to determine which action to perform.

A request code has 4 main parts

    1. A Magic number - 8 bits
    2. A sequence number - 8 bits
    3. Argument type (typically 14 bits), if any.
    4. Direction of data transfer (2 bits).  

If the request code is SETFONT to set font on a printer, the direction for data transfer will be from user application to device driver module (The user application sends the font name "Arial" to the printer). If the request code is GETFONT, direction is from printer to the user application.

In order to generate a request code, Linux provides some predefined function-like macros.

1._IO(MAGIC, SEQ_NO) both are 8 bits, 0 to 255, e.g. let us say we want to pause printer. This does not require a data transfer. So we would generate the request code as below

#define PRIN_MAGIC 'P'
#define NUM 0
#define PAUSE_PRIN __IO(PRIN_MAGIC, NUM) 

and now use ioctl as

ret_val = ioctl(fd, PAUSE_PRIN);

The corresponding system call in the driver module will receive the code and pause the printer.

  1. __IOW(MAGIC, SEQ_NO, TYPE) MAGIC and SEQ_NO are the same as above, and TYPE gives the type of the next argument, recall the third argument of ioctl is void *. W in __IOW indicates that the data flow is from user application to driver module. As an example, suppose we want to set the printer font to "Arial".
#define PRIN_MAGIC 'S'
#define SEQ_NO 1
#define SETFONT __IOW(PRIN_MAGIC, SEQ_NO, unsigned long)

further,

char *font = "Arial";
ret_val = ioctl(fd, SETFONT, font); 

Now font is a pointer, which means it is an address best represented as unsigned long, hence the third part of _IOW mentions type as such. Also, this address of font is passed to corresponding system call implemented in device driver module as unsigned long and we need to cast it to proper type before using it. Kernel space can access user space and hence this works. other two function-like macros are __IOR(MAGIC, SEQ_NO, TYPE) and __IORW(MAGIC, SEQ_NO, TYPE) where the data flow will be from kernel space to user space and both ways respectively.

Please let me know if this helps!

How to nicely format floating numbers to string without unnecessary decimal 0's

This is what I came up with:

  private static String format(final double dbl) {
    return dbl % 1 != 0 ? String.valueOf(dbl) : String.valueOf((int) dbl);
  }

It is a simple one-liner and only casts to int if it really needs to.

Run bash script from Windows PowerShell

If you add the extension .SH to the environment variable PATHEXT, you will be able to run shell scripts from PowerShell by only using the script name with arguments:

PS> .\script.sh args

If you store your scripts in a directory that is included in your PATH environment variable, you can run it from anywhere, and omit the extension and path:

PS> script args

Note: sh.exe or another *nix shell must be associated with the .sh extension.

Autowiring two beans implementing same interface - how to set default bean to autowire?

The reason why @Resource(name = "{your child class name}") works but @Autowired sometimes don't work is because of the difference of their Matching sequence

Matching sequence of @Autowire
Type, Qualifier, Name

Matching sequence of @Resource
Name, Type, Qualifier

The more detail explanation can be found here:
Inject and Resource and Autowired annotations

In this case, different child class inherited from the parent class or interface confuses @Autowire, because they are from same type; As @Resource use Name as first matching priority , it works.

Add image to left of text via css

Try something like:

.create
 { 
  margin: 0px;
  padding-left: 20px;
  background-image: url('yourpic.gif');
    background-repeat: no-repeat;

}

How to set margin with jquery?

Set it with a px value. Changing the code like below should work

el.css('marginLeft', mrg + 'px');

Does not contain a static 'main' method suitable for an entry point

For some others coming here:

In my case I had copied a .csproj from a sample project which included <EnableDefaultCompileItems>false</EnableDefaultCompileItems> without including the Program.cs file. Fix was to either remove EnableDefaultCompileItems or include Program.cs in the compile explicitly

How to print HTML content on click of a button, but not the page?

According to this SO link you can print a specific div with

w=window.open();
w.document.write(document.getElementsByClassName('report_left_inner')[0].innerH??TML);
w.print();
w.close();

How to remove lines in a Matplotlib plot

Hopefully this can help others: The above examples use ax.lines. With more recent mpl (3.3.1), there is ax.get_lines(). This bypasses the need for calling ax.lines=[]

for line in ax.get_lines(): # ax.lines:
    line.remove()
# ax.lines=[] # needed to complete removal when using ax.lines

JavaScript: replace last occurrence of text in a string

Not as elegant as the regex answers above, but easier to follow for the not-as-savvy among us:

function removeLastInstance(badtext, str) {
    var charpos = str.lastIndexOf(badtext);
    if (charpos<0) return str;
    ptone = str.substring(0,charpos);
    pttwo = str.substring(charpos+(badtext.length));
    return (ptone+pttwo);
}

I realize this is likely slower and more wasteful than the regex examples, but I think it might be helpful as an illustration of how string manipulations can be done. (It can also be condensed a bit, but again, I wanted each step to be clear.)

chart.js load totally new data

Chart JS 2.0

Just set chart.data.labels = [];

For example:

function addData(chart, label, data) {
    chart.data.labels.push(label);
    chart.data.datasets.forEach((dataset) => {
       dataset.data.push(data);
    });
    chart.update();
}

$chart.data.labels = [];

$.each(res.grouped, function(i,o) {
   addData($chart, o.age, o.count);
});
$chart.update();

How to get the size of a range in Excel

The Range object has both width and height properties, which are measured in points.

Check if an element is present in an array

Code:

function isInArray(value, array) {
  return array.indexOf(value) > -1;
}

Execution:

isInArray(1, [1,2,3]); // true

Update (2017):

In modern browsers which follow the ECMAScript 2016 (ES7) standard, you can use the function Array.prototype.includes, which makes it way more easier to check if an item is present in an array:

_x000D_
_x000D_
const array = [1, 2, 3];_x000D_
const value = 1;_x000D_
const isInArray = array.includes(value);_x000D_
console.log(isInArray); // true
_x000D_
_x000D_
_x000D_

There has been an error processing your request, Error log record number

In my case this problem appears when magento updated automatically. I restored my back up and bingo it starts working properly.

How can I get the first two digits of a number?

Comparing the O(n) time solution with the "constant time" O(1) solution provided in other answers goes to show that if the O(n) algorithm is fast enough, n may have to get very large before it is slower than a slow O(1).

The strings version is approx. 60% faster than the "maths" version for numbers of 20 or fewer digits. They become closer only when then number of digits approaches 200 digits

# the "maths" version
import math

def first_n_digits1(num, n):
    return num // 10 ** (int(math.log(num, 10)) - n + 1)

%timeit first_n_digits1(34523452452, 2)
1.21 µs ± 75 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits1(34523452452, 8)
1.24 µs ± 47.5 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 22 digits
%timeit first_n_digits1(3423234239472523452452, 2)
1.33 µs ± 59.4 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits1(3423234239472523452452, 15)
1.23 µs ± 61.2 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 196 digits
%timeit first_n_digits1(3423234239472523409283475908723908723409872390871243908172340987123409871234012089172340987734507612340981344509873123401234670350981234098123140987314509812734091823509871345109871234098172340987125988123452452, 39)
1.86 µs ± 21.8 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

# The "string" verions
def first_n_digits2(num, n):
    return int(str(num)[:n])

%timeit first_n_digits2(34523452452, 2)
744 ns ± 28.1 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits2(34523452452, 8)
768 ns ± 42.7 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 22 digits
%timeit first_n_digits2(3423234239472523452452, 2)
767 ns ± 33.6 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit first_n_digits2(3423234239472523452452, 15)
830 ns ± 55.1 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

# 196 digits
%timeit first_n_digits2(3423234239472523409283475908723908723409872390871243908098712340987123401208917234098773450761234098134450987312340123467035098123409812314098734091823509871345109871234098172340987125988123452452, 39)
1.87 µs ± 140 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

java.net.SocketException: Software caused connection abort: recv failed

Look if you have another service or program running on the http port. It happened to me when I tried to use the port and it was taken by another program.

How to convert image file data in a byte array to a Bitmap?

The answer of Uttam didnt work for me. I just got null when I do:

Bitmap bitmap = BitmapFactory.decodeByteArray(bitmapdata, 0, bitmapdata.length);

In my case, bitmapdata only has the buffer of the pixels, so it is imposible for the function decodeByteArray to guess which the width, the height and the color bits use. So I tried this and it worked:

//Create bitmap with width, height, and 4 bytes color (RGBA)    
Bitmap bmp = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888);
ByteBuffer buffer = ByteBuffer.wrap(bitmapdata);
bmp.copyPixelsFromBuffer(buffer);

Check https://developer.android.com/reference/android/graphics/Bitmap.Config.html for different color options

Using Default Arguments in a Function

You can't do this directly, but a little code fiddling makes it possible to emulate.

function foo($blah, $x = false, $y = false) {
  if (!$x) $x = "some value";
  if (!$y) $y = "some other value";

  // code
}

How to use OrderBy with findAll in Spring Data

I try in this example to show you a complete example to personalize your OrderBy sorts

 import java.util.List;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.jpa.repository.*;
 import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 import org.springframework.data.domain.Sort;
 /**
 * Spring Data  repository for the User entity.
 */
 @SuppressWarnings("unused")
 @Repository
 public interface UserRepository extends JpaRepository<User, Long> {
 List <User> findAllWithCustomOrderBy(Sort sort);
 }

you will use this example : A method for build dynamically a object that instance of Sort :

import org.springframework.data.domain.Sort;
public class SampleOrderBySpring{
 Sort dynamicOrderBySort = createSort();
     public static void main( String[] args )
     {
       System.out.println("default sort \"firstName\",\"name\",\"age\",\"size\" ");
       Sort defaultSort = createStaticSort();
       System.out.println(userRepository.findAllWithCustomOrderBy(defaultSort ));


       String[] orderBySortedArray = {"name", "firstName"};
       System.out.println("default sort ,\"name\",\"firstName\" ");
       Sort dynamicSort = createDynamicSort(orderBySortedArray );
       System.out.println(userRepository.findAllWithCustomOrderBy(dynamicSort ));
      }
      public Sort createDynamicSort(String[] arrayOrdre) {
        return  Sort.by(arrayOrdre);
        }

   public Sort createStaticSort() {
        String[] arrayOrdre  ={"firstName","name","age","size");
        return  Sort.by(arrayOrdre);
        }
}

Java web start - Unable to load resource

I've changed the java proxy settings to direct connection - and it works.

Show Youtube video source into HTML5 video tag?

I have created a realtively small (4.89 KB) javascript library for this exact functionality.

Found on my GitHub here: https://github.com/thelevicole/youtube-to-html5-loader/

It's as simple as:

<video data-yt2html5="https://www.youtube.com/watch?v=ScMzIvxBSi4"></video>

<script src="https://cdn.jsdelivr.net/gh/thelevicole/[email protected]/dist/YouTubeToHtml5.js"></script>
<script>new YouTubeToHtml5();</script>

Working example here: https://jsfiddle.net/thelevicole/5g6dbpx3/1/

What the library does is extract the video ID from the data attribute and makes a request to the https://www.youtube.com/get_video_info?video_id=. It decodes the response which includes streaming information we can use to add a source to the <video> tag.

Exclude subpackages from Spring autowiring?

You can also include specific package and excludes them like :

Include and exclude (both)

 @SpringBootApplication
        (
                scanBasePackages = {
                        "com.package1",
                        "com.package2"
                },
                exclude = {org.springframework.boot.sample.class}
        )

JUST Exclude

@SpringBootApplication(exclude= {com.package1.class})
public class MySpringConfiguration {}

String concatenation of two pandas columns

This question has already been answered, but I believe it would be good to throw some useful methods not previously discussed into the mix, and compare all methods proposed thus far in terms of performance.

Here are some useful solutions to this problem, in increasing order of performance.


DataFrame.agg

This is a simple str.format-based approach.

df['baz'] = df.agg('{0[bar]} is {0[foo]}'.format, axis=1)
df
  foo  bar     baz
0   a    1  1 is a
1   b    2  2 is b
2   c    3  3 is c

You can also use f-string formatting here:

df['baz'] = df.agg(lambda x: f"{x['bar']} is {x['foo']}", axis=1)
df
  foo  bar     baz
0   a    1  1 is a
1   b    2  2 is b
2   c    3  3 is c

char.array-based Concatenation

Convert the columns to concatenate as chararrays, then add them together.

a = np.char.array(df['bar'].values)
b = np.char.array(df['foo'].values)

df['baz'] = (a + b' is ' + b).astype(str)
df
  foo  bar     baz
0   a    1  1 is a
1   b    2  2 is b
2   c    3  3 is c

List Comprehension with zip

I cannot overstate how underrated list comprehensions are in pandas.

df['baz'] = [str(x) + ' is ' + y for x, y in zip(df['bar'], df['foo'])]

Alternatively, using str.join to concat (will also scale better):

df['baz'] = [
    ' '.join([str(x), 'is', y]) for x, y in zip(df['bar'], df['foo'])]

df
  foo  bar     baz
0   a    1  1 is a
1   b    2  2 is b
2   c    3  3 is c

List comprehensions excel in string manipulation, because string operations are inherently hard to vectorize, and most pandas "vectorised" functions are basically wrappers around loops. I have written extensively about this topic in For loops with pandas - When should I care?. In general, if you don't have to worry about index alignment, use a list comprehension when dealing with string and regex operations.

The list comp above by default does not handle NaNs. However, you could always write a function wrapping a try-except if you needed to handle it.

def try_concat(x, y):
    try:
        return str(x) + ' is ' + y
    except (ValueError, TypeError):
        return np.nan


df['baz'] = [try_concat(x, y) for x, y in zip(df['bar'], df['foo'])]

perfplot Performance Measurements

enter image description here

Graph generated using perfplot. Here's the complete code listing.

Functions

def brenbarn(df):
    return df.assign(baz=df.bar.map(str) + " is " + df.foo)

def danielvelkov(df):
    return df.assign(baz=df.apply(
        lambda x:'%s is %s' % (x['bar'],x['foo']),axis=1))

def chrimuelle(df):
    return df.assign(
        baz=df['bar'].astype(str).str.cat(df['foo'].values, sep=' is '))

def vladimiryashin(df):
    return df.assign(baz=df.astype(str).apply(lambda x: ' is '.join(x), axis=1))

def erickfis(df):
    return df.assign(
        baz=df.apply(lambda x: f"{x['bar']} is {x['foo']}", axis=1))

def cs1_format(df):
    return df.assign(baz=df.agg('{0[bar]} is {0[foo]}'.format, axis=1))

def cs1_fstrings(df):
    return df.assign(baz=df.agg(lambda x: f"{x['bar']} is {x['foo']}", axis=1))

def cs2(df):
    a = np.char.array(df['bar'].values)
    b = np.char.array(df['foo'].values)

    return df.assign(baz=(a + b' is ' + b).astype(str))

def cs3(df):
    return df.assign(
        baz=[str(x) + ' is ' + y for x, y in zip(df['bar'], df['foo'])])

How to run a cron job inside a docker container?

Cron jobs are stored in /var/spool/cron/crontabs (Common place in all distros I Know). BTW, You can create a cron tab in bash using something like that:

crontab -l > cronexample
echo "00 09 * * 1-5 echo hello" >> cronexample
crontab cronexample
rm cronexample

This will create a temporary file with cron task, then program it using crontab. Last line remove temporary file.

Remove Duplicates from range of cells in excel vba

To remove duplicates from a single column

 Sub removeDuplicate()
 'removeDuplicate Macro
 Columns("A:A").Select
 ActiveSheet.Range("$A$1:$A$117").RemoveDuplicates Columns:=Array(1), _ 
 Header:=xlNo 
 Range("A1").Select
 End Sub

if you have header then use Header:=xlYes

Increase your range as per your requirement.
you can make it to 1000 like this :

ActiveSheet.Range("$A$1:$A$1000")

More info here here

How to update values in a specific row in a Python Pandas DataFrame?

There are probably a few ways to do this, but one approach would be to merge the two dataframes together on the filename/m column, then populate the column 'n' from the right dataframe if a match was found. The n_x, n_y in the code refer to the left/right dataframes in the merge.

In[100] : df = pd.merge(df1, df2, how='left', on=['filename','m'])

In[101] : df
Out[101]: 
    filename   m   n_x  n_y
0  test0.dat  12  None  NaN
1  test2.dat  13  None   16

In[102] : df['n'] = df['n_y'].fillna(df['n_x'])

In[103] : df = df.drop(['n_x','n_y'], axis=1)

In[104] : df
Out[104]: 
    filename   m     n
0  test0.dat  12  None
1  test2.dat  13    16

'ls' in CMD on Windows is not recognized

Use the command dir to list all the directories and files in a directory; ls is a unix command.

How to take keyboard input in JavaScript?

Use JQuery keydown event.

$(document).keypress(function(){
    if(event.which == 70){  //f
        console.log("You have payed respect");
    }
});

In JS; keyboard keys are identified by Javascript keycodes

git checkout master error: the following untracked working tree files would be overwritten by checkout

Try git checkout -f master.

-f or --force

Source: https://www.kernel.org/pub/software/scm/git/docs/git-checkout.html

When switching branches, proceed even if the index or the working tree differs from HEAD. This is used to throw away local changes.

When checking out paths from the index, do not fail upon unmerged entries; instead, unmerged entries are ignored.

Git merge two local branches

For merging first branch to second one:

on first branch: git merge secondBranch

on second branch: Move to first branch-> git checkout firstBranch-> git merge secondBranch

Change collations of all columns of all tables in SQL Server

So here I am, once again, not satisfied with the answer. I was tasked to upgrade JIRA 6.4.x to JIRA Software 7.x and I went to that particular problem with the database and column collation.

In SQL Server, if you do not drop constrains such as primary key or foreign key or even indexes, the script provided above as an answer doesn't work at all. It will however change those without those properties. This is really problematic, because I don't want to manually drop all constrains and create them back. That operation could probably ends up with errors. On the other side, creating a script automating the change could take ages to make.

So I found a way to make the migration simply by using SQL Management Studio. Here's the procedure:

  • Rename the database by something else. By example, mine's was "Jira", so I renamed it "JiraTemp".
  • Create a new database named "Jira" and make sure to set the right collation. Simply select the page "Options" and change the collation.
  • Once created, go back to "JiraTemp", right click it, "Tasks -> Generate Scripts...".
    • Select "Script entire database and all database objects".
    • Select "Save to new query window", then select "Advanced"
    • Change the value of "Script for Server Version" for the desired value
    • Enable "Script Object-Level Permissions", "Script Owner" and "Script Full-Text Indexes"
    • Leave everything else as is or personalize it if you wish.
  • Once generated, delete the "CREATE DATABASE" section. Replace "JiraTemp" by "Jira".
  • Run the script. The entire database structure and permissions of the database is now replicated to "Jira".
  • Before we copy the data, we need to disable all constrains. Execute the following command to do so in the database "Jira": EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"
  • Now the data needs to be transferred. To do so, simply right click "JiraTemp", then select "Tasks -> Export Data..."
    • Select as data source and destination the OLE DB Provider for SQL Server.
    • Source database is "JiraTemp"
    • Destination database is "Jira"
    • The server name is technically the same for source and destination (except if you've created the database on another server).
    • Select "Copy data from one or another tables or views"
    • Select all tables except views. Then, when still highlighted, click on "Edit Mappings". Check "Enable identity insert"
    • Click OK, Next, then Finish
  • Data transfer can take a while. Once finished, execute the following command to re enable all constrains: exec sp_msforeachtable @command1="print '?'", @command2="ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"

Once completed, I've restarted JIRA and my database collation was in order. Hope it helps a lot of people!

ASP.NET MVC Return Json Result?

It should be :

public async Task<ActionResult> GetSomeJsonData()
{
    var model = // ... get data or build model etc.

    return Json(new { Data = model }, JsonRequestBehavior.AllowGet); 
}

or more simply:

return Json(model, JsonRequestBehavior.AllowGet); 

I did notice that you are calling GetResources() from another ActionResult which wont work. If you are looking to get JSON back, you should be calling GetResources() from ajax directly...

Angularjs $http.get().then and binding to a list

Try using the success() call back

$http.get('/Documents/DocumentsList/' + caseId).success(function (result) {
    $scope.Documents = result;
});

But now since Documents is an array and not a promise, remove the ()

<li ng-repeat="document in Documents" ng-class="IsFiltered(document.Filtered)"> <span>
           <input type="checkbox" name="docChecked" id="doc_{{document.Id}}" ng-model="document.Filtered" />
        </span>
 <span>{{document.Name}}</span>

</li>

How do I add FTP support to Eclipse?

have you checked RSE (Remote System Explorer) ? I think it's pretty close to what you want to achieve.

a blog post about it, with screenshots

Get Image Height and Width as integer values?

list($width, $height) = getimagesize($filename)

Or,

$data = getimagesize($filename);
$width = $data[0];
$height = $data[1];

how to create inline style with :before and :after

You can, using CSS variables (more precisely called CSS custom properties).

  • Set your variable in your style attribute:
    style="--my-color-var: orange;"
  • Use the variable in your stylesheet:
    background-color: var(--my-color-var);

Browser compatibility

Minimal example:

_x000D_
_x000D_
div {
  width: 100px;
  height: 100px;
  position: relative;
  border: 1px solid black;
}

div:after {
  background-color: var(--my-color-var);
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  left: 0;
}
_x000D_
<div style="--my-color-var: orange;"></div>
_x000D_
_x000D_
_x000D_

Your example:

_x000D_
_x000D_
.bubble {
  position: relative;
  width: 30px;
  height: 15px;
  padding: 0;
  background: #FFF;
  border: 1px solid #000;
  border-radius: 5px;
  text-align: center;
  background-color: var(--bubble-color);
}

.bubble:after {
  content: "";
  position: absolute;
  top: 4px;
  left: -4px;
  border-style: solid;
  border-width: 3px 4px 3px 0;
  border-color: transparent var(--bubble-color);
   display: block;
  width: 0;
  z-index: 1;
  
}

.bubble:before {
  content: "";
  position: absolute;
  top: 4px;
  left: -5px;
  border-style: solid;
  border-width: 3px 4px 3px 0;
  border-color: transparent #000;
  display: block;
  width: 0;
  z-index: 0;
}
_x000D_
<div class='bubble' style="--bubble-color: rgb(100,255,255);"> 100 </div>
_x000D_
_x000D_
_x000D_

how to use XPath with XDocument?

If you have XDocument it is easier to use LINQ-to-XML:

var document = XDocument.Load(fileName);
var name = document.Descendants(XName.Get("Name", @"http://demo.com/2011/demo-schema")).First().Value;

If you are sure that XPath is the only solution you need:

using System.Xml.XPath;

var document = XDocument.Load(fileName);
var namespaceManager = new XmlNamespaceManager(new NameTable());
namespaceManager.AddNamespace("empty", "http://demo.com/2011/demo-schema");
var name = document.XPathSelectElement("/empty:Report/empty:ReportInfo/empty:Name", namespaceManager).Value;

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException Error

NullPointerExceptions are among the easier exceptions to diagnose, frequently. Whenever you get an exception in Java and you see the stack trace ( that's what your second quote-block is called, by the way ), you read from top to bottom. Often, you will see exceptions that start in Java library code or in native implementations methods, for diagnosis you can just skip past those until you see a code file that you wrote.

Then you like at the line indicated and look at each of the objects ( instantiated classes ) on that line -- one of them was not created and you tried to use it. You can start by looking up in your code to see if you called the constructor on that object. If you didn't, then that's your problem, you need to instantiate that object by calling new Classname( arguments ). Another frequent cause of NullPointerExceptions is accidentally declaring an object with local scope when there is an instance variable with the same name.

In your case, the exception occurred in your constructor for Workshop on line 75. <init> means the constructor for a class. If you look on that line in your code, you'll see the line

denimjeansButton.addItemListener(this);

There are fairly clearly two objects on this line: denimjeansButton and this. this is synonymous with the class instance you are currently in and you're in the constructor, so it can't be this. denimjeansButton is your culprit. You never instantiated that object. Either remove the reference to the instance variable denimjeansButton or instantiate it.

Difference between DOM parentNode and parentElement

Use .parentElement and you can't go wrong as long as you aren't using document fragments.

If you use document fragments, then you need .parentNode:

let div = document.createDocumentFragment().appendChild(document.createElement('div'));
div.parentElement // null
div.parentNode // document fragment

Also:

_x000D_
_x000D_
let div = document.getElementById('t').content.firstChild_x000D_
div.parentElement // null_x000D_
div.parentNode // document fragment
_x000D_
<template id="t"><div></div></template>
_x000D_
_x000D_
_x000D_


Apparently the <html>'s .parentNode links to the Document. This should be considered a decision phail as documents aren't nodes since nodes are defined to be containable by documents and documents can't be contained by documents.

RSA Public Key format

Starting from the decoded base64 data of an OpenSSL rsa-ssh Key, i've been able to guess a format:

  • 00 00 00 07: four byte length prefix (7 bytes)
  • 73 73 68 2d 72 73 61: "ssh-rsa"
  • 00 00 00 01: four byte length prefix (1 byte)
  • 25: RSA Exponent (e): 25
  • 00 00 01 00: four byte length prefix (256 bytes)
  • RSA Modulus (n):

    7f 9c 09 8e 8d 39 9e cc d5 03 29 8b c4 78 84 5f
    d9 89 f0 33 df ee 50 6d 5d d0 16 2c 73 cf ed 46 
    dc 7e 44 68 bb 37 69 54 6e 9e f6 f0 c5 c6 c1 d9 
    cb f6 87 78 70 8b 73 93 2f f3 55 d2 d9 13 67 32 
    70 e6 b5 f3 10 4a f5 c3 96 99 c2 92 d0 0f 05 60 
    1c 44 41 62 7f ab d6 15 52 06 5b 14 a7 d8 19 a1 
    90 c6 c1 11 f8 0d 30 fd f5 fc 00 bb a4 ef c9 2d 
    3f 7d 4a eb d2 dc 42 0c 48 b2 5e eb 37 3c 6c a0 
    e4 0a 27 f0 88 c4 e1 8c 33 17 33 61 38 84 a0 bb 
    d0 85 aa 45 40 cb 37 14 bf 7a 76 27 4a af f4 1b 
    ad f0 75 59 3e ac df cd fc 48 46 97 7e 06 6f 2d 
    e7 f5 60 1d b1 99 f8 5b 4f d3 97 14 4d c5 5e f8 
    76 50 f0 5f 37 e7 df 13 b8 a2 6b 24 1f ff 65 d1 
    fb c8 f8 37 86 d6 df 40 e2 3e d3 90 2c 65 2b 1f 
    5c b9 5f fa e9 35 93 65 59 6d be 8c 62 31 a9 9b 
    60 5a 0e e5 4f 2d e6 5f 2e 71 f3 7e 92 8f fe 8b
    

The closest validation of my theory i can find it from RFC 4253:

The "ssh-rsa" key format has the following specific encoding:

  string    "ssh-rsa"
  mpint     e
  mpint     n

Here the 'e' and 'n' parameters form the signature key blob.

But it doesn't explain the length prefixes.


Taking the random RSA PUBLIC KEY i found (in the question), and decoding the base64 into hex:

30 82 01 0a 02 82 01 01 00 fb 11 99 ff 07 33 f6 e8 05 a4 fd 3b 36 ca 68 
e9 4d 7b 97 46 21 16 21 69 c7 15 38 a5 39 37 2e 27 f3 f5 1d f3 b0 8b 2e 
11 1c 2d 6b bf 9f 58 87 f1 3a 8d b4 f1 eb 6d fe 38 6c 92 25 68 75 21 2d 
dd 00 46 87 85 c1 8a 9c 96 a2 92 b0 67 dd c7 1d a0 d5 64 00 0b 8b fd 80 
fb 14 c1 b5 67 44 a3 b5 c6 52 e8 ca 0e f0 b6 fd a6 4a ba 47 e3 a4 e8 94 
23 c0 21 2c 07 e3 9a 57 03 fd 46 75 40 f8 74 98 7b 20 95 13 42 9a 90 b0 
9b 04 97 03 d5 4d 9a 1c fe 3e 20 7e 0e 69 78 59 69 ca 5b f5 47 a3 6b a3 
4d 7c 6a ef e7 9f 31 4e 07 d9 f9 f2 dd 27 b7 29 83 ac 14 f1 46 67 54 cd 
41 26 25 16 e4 a1 5a b1 cf b6 22 e6 51 d3 e8 3f a0 95 da 63 0b d6 d9 3e 
97 b0 c8 22 a5 eb 42 12 d4 28 30 02 78 ce 6b a0 cc 74 90 b8 54 58 1f 0f 
fb 4b a3 d4 23 65 34 de 09 45 99 42 ef 11 5f aa 23 1b 15 15 3d 67 83 7a 
63 02 03 01 00 01

From RFC3447 - Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1:

A.1.1 RSA public key syntax

An RSA public key should be represented with the ASN.1 type RSAPublicKey:

  RSAPublicKey ::= SEQUENCE {
     modulus           INTEGER,  -- n
     publicExponent    INTEGER   -- e
  }

The fields of type RSAPublicKey have the following meanings:

  • modulus is the RSA modulus n.
  • publicExponent is the RSA public exponent e.

Using Microsoft's excellent (and the only real) ASN.1 documentation:

30 82 01 0a       ;SEQUENCE (0x010A bytes: 266 bytes)
|  02 82 01 01    ;INTEGER  (0x0101 bytes: 257 bytes)
|  |  00          ;leading zero because high-bit, but number is positive
|  |  fb 11 99 ff 07 33 f6 e8 05 a4 fd 3b 36 ca 68 
|  |  e9 4d 7b 97 46 21 16 21 69 c7 15 38 a5 39 37 2e 27 f3 f5 1d f3 b0 8b 2e 
|  |  11 1c 2d 6b bf 9f 58 87 f1 3a 8d b4 f1 eb 6d fe 38 6c 92 25 68 75 21 2d 
|  |  dd 00 46 87 85 c1 8a 9c 96 a2 92 b0 67 dd c7 1d a0 d5 64 00 0b 8b fd 80 
|  |  fb 14 c1 b5 67 44 a3 b5 c6 52 e8 ca 0e f0 b6 fd a6 4a ba 47 e3 a4 e8 94 
|  |  23 c0 21 2c 07 e3 9a 57 03 fd 46 75 40 f8 74 98 7b 20 95 13 42 9a 90 b0 
|  |  9b 04 97 03 d5 4d 9a 1c fe 3e 20 7e 0e 69 78 59 69 ca 5b f5 47 a3 6b a3 
|  |  4d 7c 6a ef e7 9f 31 4e 07 d9 f9 f2 dd 27 b7 29 83 ac 14 f1 46 67 54 cd 
|  |  41 26 25 16 e4 a1 5a b1 cf b6 22 e6 51 d3 e8 3f a0 95 da 63 0b d6 d9 3e 
|  |  97 b0 c8 22 a5 eb 42 12 d4 28 30 02 78 ce 6b a0 cc 74 90 b8 54 58 1f 0f 
|  |  fb 4b a3 d4 23 65 34 de 09 45 99 42 ef 11 5f aa 23 1b 15 15 3d 67 83 7a 
|  |  63 
|  02 03          ;INTEGER (3 bytes)
|     01 00 01

giving the public key modulus and exponent:

  • modulus = 0xfb1199ff0733f6e805a4fd3b36ca68...837a63
  • exponent = 65,537

Update: My expanded form of this answer in another question

change directory in batch file using variable

simple way to do this... here are the example

cd program files
cd poweriso
piso mount D:\<Filename.iso> <Virtual Drive>
Pause

this will mount the ISO image to the specific drive...use

How to access elements of a JArray (or iterate over them)

Once you have a JArray you can treat it just like any other Enumerable object, and using linq you can access them, check them, verify them, and select them.

var str = @"[1, 2, 3]";
var jArray = JArray.Parse(str);
Console.WriteLine(String.Join("-", jArray.Where(i => (int)i > 1).Select(i => i.ToString())));

Update Jenkins from a war file

Though I wouldn't consider this as a valid answer to OP's question, I'd still emphasize that the best way to deploy Jenkins (and likely most if not all libraries/packages/software) on Ubuntu is to leverage aptitude (or apt-get) management system.

It is documented here: https://wiki.jenkins-ci.org/display/JENKINS/Installing+Jenkins+on+Ubuntu (notice that if you want to use the LTS build, hit on this repo http://pkg.jenkins-ci.org/debian-stable/)

So if by any chance you actually did use this approach, you'd simply do a apt-get upgrade jenkins

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

This works for me, the source is here

int MY_PERMISSIONS_REQUEST_CAMERA=0;
// Here, this is the current activity
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
{
     if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA))
     {

     }
     else
     {
          ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA );
          // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
          // app-defined int constant. The callback method gets the
          // result of the request.
      }
}

How can I read a text file from the SD card in Android?

Beware: some phones have 2 sdcards , an internal fixed one and a removable card. You can find the name of the last one via a standard app:"Mijn Bestanden" ( in English: "MyFiles" ? ) When I open this app (item:all files) the path of the open folder is "/sdcard" ,scrolling down there is an entry "external-sd" , clicking this opens the folder "/sdcard/external_sd/" . Suppose I want to open a text-file "MyBooks.txt" I would use something as :

   String Filename = "/mnt/sdcard/external_sd/MyBooks.txt" ;
   File file = new File(fname);...etc...

Left padding a String with Zeros

Here is a solution based on String.format that will work for strings and is suitable for variable length.

public static String PadLeft(String stringToPad, int padToLength){
    String retValue = null;
    if(stringToPad.length() < padToLength) {
        retValue = String.format("%0" + String.valueOf(padToLength - stringToPad.length()) + "d%s",0,stringToPad);
    }
    else{
        retValue = stringToPad;
    }
    return retValue;
}

public static void main(String[] args) {
    System.out.println("'" + PadLeft("test", 10) + "'");
    System.out.println("'" + PadLeft("test", 3) + "'");
    System.out.println("'" + PadLeft("test", 4) + "'");
    System.out.println("'" + PadLeft("test", 5) + "'");
}

Output: '000000test' 'test' 'test' '0test'

'No database provider has been configured for this DbContext' on SignInManager.PasswordSignInAsync

I could resolve it by overriding Configuration in MyContext through adding connection string to the DbContextOptionsBuilder:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        if (!optionsBuilder.IsConfigured)
        {
            IConfigurationRoot configuration = new ConfigurationBuilder()
               .SetBasePath(Directory.GetCurrentDirectory())
               .AddJsonFile("appsettings.json")
               .Build();
            var connectionString = configuration.GetConnectionString("DbCoreConnectionString");
            optionsBuilder.UseSqlServer(connectionString);
        }
    }

The entity cannot be constructed in a LINQ to Entities query

If you are using Entity framework, then try removing property from DbContext which uses your complex model as Entity I had same problem when mapping multiple model into a viewmodel named Entity

public DbSet<Entity> Entities { get; set; }

Removing the entry from DbContext fixed my error.

Difference Between One-to-Many, Many-to-One and Many-to-Many?

Looks like everyone is answering One-to-many vs. Many-to-many:

The difference between One-to-many, Many-to-one and Many-to-Many is:

One-to-many vs Many-to-one is a matter of perspective. Unidirectional vs Bidirectional will not affect the mapping but will make difference on how you can access your data.

  • In Many-to-one the many side will keep reference of the one side. A good example is "A State has Cities". In this case State is the one side and City is the many side. There will be a column state_id in the table cities.

In unidirectional, Person class will have List<Skill> skills but Skill will not have Person person. In bidirectional, both properties are added and it allows you to access a Person given a skill( i.e. skill.person).

  • In One-to-Many the one side will be our point of reference. For example, "A User has Addresses". In this case we might have three columns address_1_id, address_2_id and address_3_id or a look up table with multi column unique constraint on user_id on address_id.

In unidirectional, a User will have Address address. Bidirectional will have an additional List<User> users in the Address class.

  • In Many-to-Many members of each party can hold reference to arbitrary number of members of the other party. To achieve this a look up table is used. Example for this is the relationship between doctors and patients. A doctor can have many patients and vice versa.

Show a leading zero if a number is less than 10

Try this

function pad (str, max) {
  return str.length < max ? pad("0" + str, max) : str;
}

alert(pad("5", 2));

Example

http://jsfiddle.net/

Or

var number = 5;
var i;
if (number < 10) {
    alert("0"+number);
}

Example

http://jsfiddle.net/

"The system cannot find the file specified"

Server Error in '/' Application.

The system cannot find the file specified

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ComponentModel.Win32Exception: The system cannot find the file specified

Source Error:

     {
                   SqlCommand cmd = new SqlCommand("select * from tblemployee",con);
                   con.Open();
                   GridView1.DataSource = cmd.ExecuteReader();
                   GridView1.DataBind();

Source File: d:\C# programs\kudvenkat\adobasics1\adobasics1\employeedata.aspx.cs Line: 23

if your error is same like mine..just do this

right click on your table in sqlserver object explorer,choose properties in lower left corner in general option there is a connection block with server and connection specification.in your web config for datasource=. or local choose name specified in server in properties..

iPhone hide Navigation Bar only on first page

The nicest solution I have found is to do the following in the first view controller.

Objective-C

- (void)viewWillAppear:(BOOL)animated {
    [self.navigationController setNavigationBarHidden:YES animated:animated];
    [super viewWillAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated {
    [self.navigationController setNavigationBarHidden:NO animated:animated];
    [super viewWillDisappear:animated];
}

Swift

override func viewWillAppear(_ animated: Bool) {
    self.navigationController?.setNavigationBarHidden(true, animated: animated)
    super.viewWillAppear(animated)
}

override func viewWillDisappear(_ animated: Bool) {
    self.navigationController?.setNavigationBarHidden(false, animated: animated)
    super.viewWillDisappear(animated)
} 

This will cause the navigation bar to animate in from the left (together with the next view) when you push the next UIViewController on the stack, and animate away to the left (together with the old view), when you press the back button on the UINavigationBar.

Please note also that these are not delegate methods, you are overriding UIViewController's implementation of these methods, and according to the documentation you must call the super's implementation somewhere in your implementation.

How do change the color of the text of an <option> within a <select>?

You can't have HTML code inside the options, they can only contain text, but you can apply the class to the option instead:

<option selected="selected" class="grey_color">select one option</option>

Demo: http://jsfiddle.net/Guffa/hUpAB/9/

Note:

  • The support for styling options varies between browsers. In modern brosers you generally can expect support for coloring but not for font size. A browser in a phone for example usually doesn't display the options in a dropdown, so the styling would not be relevant at all.
  • You should not have html and head tags in the HTML code in jsfiddle.
  • You should name your classes for what the represent, not how they look.

Setting cursor at the end of any text of a textbox

Try like below... it will help you...

Some time in Window Form Focus() doesn't work correctly. So better you can use Select() to focus the textbox.

txtbox.Select(); // to Set Focus
txtbox.Select(txtbox.Text.Length, 0); //to set cursor at the end of textbox

How to use Google fonts in React.js?

If you are using Create React App environment simply add @import rule to index.css as such:

@import url('https://fonts.googleapis.com/css?family=Anton');

Import index.css in your main React app:

import './index.css'

React gives you a choice of Inline styling, CSS Modules or Styled Components in order to apply CSS:

font-family: 'Anton', sans-serif;

How to get only the date value from a Windows Forms DateTimePicker control?

Following that this question has been already given a good answer, in WinForms we can also set a Custom Format to the DateTimePicker Format property as Vivek said, this allow us to display the date/time in the specified format string within the DateTimePicker, then, it will be simple just as we do to get text from a TextBox.

// Set the Format type and the CustomFormat string.
dateTimePicker1.Format = DateTimePickerFormat.Custom;    
dateTimePicker1.CustomFormat = "yyyy/MM/dd";

dateTimePicker1

We are now able to get Date only easily by getting the Text from the DateTimePicker:

MessageBox.Show("Selected Date: " + dateTimePicker1.Text, "DateTimePicker", MessageBoxButtons.OK, MessageBoxIcon.Information);

enter image description here

NOTE: If you are planning to insert Date only data to a date column type in SQL, see this documentation related to the supported String Literal Formats for date. You can not insert a date in the format string ydm because is not supported:

dateTimePicker1.CustomFormat = "yyyy/dd/MM";  
var qr = "INSERT INTO tbl VALUES (@dtp)";
using (var insertCommand = new SqlCommand..
{
   try
   {
     insertCommand.Parameters.AddWithValue("@dtp", dateTimePicker1.Text);
     con.Open();
     insertCommand.ExecuteScalar();
   }
   catch (Exception ex)
   {
      MessageBox.Show("Exception message: " + ex.Message, "DateTimePicker", MessageBoxButtons.OK, MessageBoxIcon.Error);
   }

the above code ends in the following Exception: enter image description here

Be aware. Cheers.

Is there such a thing as min-font-size and max-font-size?

You can do it by using a formula and including the viewport width.

font-size: calc(7px + .5vw);

This sets the minimum font size at 7px and amplifies it by .5vw depending on the viewport width.

Good luck!

How to insert a SQLite record with a datetime set to 'now' in Android application?

There are a couple options you can use:

  1. You could try using the string "(DATETIME('now'))" instead.
  2. Insert the datetime yourself, ie with System.currentTimeMillis()
  3. When creating the SQLite table, specify a default value for the created_date column as the current date time.
  4. Use SQLiteDatabase.execSQL to insert directly.

Install pip in docker

An alternative is to use the Alpine Linux containers, e.g. python:2.7-alpine. They offer pip out of the box (and have a smaller footprint which leads to faster builds etc).

Error starting Tomcat from NetBeans - '127.0.0.1*' is not recognized as an internal or external command

I didnt try Sumama Waheed's answer but what worked for me was replacing the bin/catalina.jar with a working jar (I disposed of an older tomcat) and after adding in NetBeans, I put the original catalina.jar again.

How to upload, display and save images using node.js and express

First of all, you should make an HTML form containing a file input element. You also need to set the form's enctype attribute to multipart/form-data:

<form method="post" enctype="multipart/form-data" action="/upload">
    <input type="file" name="file">
    <input type="submit" value="Submit">
</form>

Assuming the form is defined in index.html stored in a directory named public relative to where your script is located, you can serve it this way:

const http = require("http");
const path = require("path");
const fs = require("fs");

const express = require("express");

const app = express();
const httpServer = http.createServer(app);

const PORT = process.env.PORT || 3000;

httpServer.listen(PORT, () => {
  console.log(`Server is listening on port ${PORT}`);
});

// put the HTML file containing your form in a directory named "public" (relative to where this script is located)
app.get("/", express.static(path.join(__dirname, "./public")));

Once that's done, users will be able to upload files to your server via that form. But to reassemble the uploaded file in your application, you'll need to parse the request body (as multipart form data).

In Express 3.x you could use express.bodyParser middleware to handle multipart forms but as of Express 4.x, there's no body parser bundled with the framework. Luckily, you can choose from one of the many available multipart/form-data parsers out there. Here, I'll be using multer:

You need to define a route to handle form posts:

const multer = require("multer");

const handleError = (err, res) => {
  res
    .status(500)
    .contentType("text/plain")
    .end("Oops! Something went wrong!");
};

const upload = multer({
  dest: "/path/to/temporary/directory/to/store/uploaded/files"
  // you might also want to set some limits: https://github.com/expressjs/multer#limits
});


app.post(
  "/upload",
  upload.single("file" /* name attribute of <file> element in your form */),
  (req, res) => {
    const tempPath = req.file.path;
    const targetPath = path.join(__dirname, "./uploads/image.png");

    if (path.extname(req.file.originalname).toLowerCase() === ".png") {
      fs.rename(tempPath, targetPath, err => {
        if (err) return handleError(err, res);

        res
          .status(200)
          .contentType("text/plain")
          .end("File uploaded!");
      });
    } else {
      fs.unlink(tempPath, err => {
        if (err) return handleError(err, res);

        res
          .status(403)
          .contentType("text/plain")
          .end("Only .png files are allowed!");
      });
    }
  }
);

In the example above, .png files posted to /upload will be saved to uploaded directory relative to where the script is located.

In order to show the uploaded image, assuming you already have an HTML page containing an img element:

<img src="/image.png" />

you can define another route in your express app and use res.sendFile to serve the stored image:

app.get("/image.png", (req, res) => {
  res.sendFile(path.join(__dirname, "./uploads/image.png"));
});

How to grep a string in a directory and all its subdirectories?

grep -r -e string directory

-r is for recursive; -e is optional but its argument specifies the regex to search for. Interestingly, POSIX grep is not required to support -r (or -R), but I'm practically certain that System V grep did, so in practice they (almost) all do. Some versions of grep support -R as well as (or conceivably instead of) -r; AFAICT, it means the same thing.

How to convert ZonedDateTime to Date?

I use this.

public class TimeTools {

    public static Date getTaipeiNowDate() {
        Instant now = Instant.now();
        ZoneId zoneId = ZoneId.of("Asia/Taipei");
        ZonedDateTime dateAndTimeInTai = ZonedDateTime.ofInstant(now, zoneId);
        try {
            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(dateAndTimeInTai.toString().substring(0, 19).replace("T", " "));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
}

Because Date.from(java.time.ZonedDateTime.ofInstant(now, zoneId).toInstant()); It's not work!!! If u run your application in your computer, it's not problem. But if you run in any region of AWS or Docker or GCP, it will generate problem. Because computer is not your timezone on Cloud. You should set your correctly timezone in Code. For example, Asia/Taipei. Then it will correct in AWS or Docker or GCP.

public class App {
    public static void main(String[] args) {
        Instant now = Instant.now();
        ZoneId zoneId = ZoneId.of("Australia/Sydney");
        ZonedDateTime dateAndTimeInLA = ZonedDateTime.ofInstant(now, zoneId);
        try {
            Date ans = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(dateAndTimeInLA.toString().substring(0, 19).replace("T", " "));
            System.out.println("ans="+ans);
        } catch (ParseException e) {
        }
        Date wrongAns = Date.from(java.time.ZonedDateTime.ofInstant(now, zoneId).toInstant());
        System.out.println("wrongAns="+wrongAns);
    }
}

C# loop - break vs. continue

Simple answer:

Break exits the loop immediately.
Continue starts processing the next item. (If there are any, by jumping to the evaluating line of the for/while)

How to search for an element in a golang slice

With a simple for loop:

for _, v := range myconfig {
    if v.Key == "key1" {
        // Found!
    }
}

Note that since element type of the slice is a struct (not a pointer), this may be inefficient if the struct type is "big" as the loop will copy each visited element into the loop variable.

It would be faster to use a range loop just on the index, this avoids copying the elements:

for i := range myconfig {
    if myconfig[i].Key == "key1" {
        // Found!
    }
}

Notes:

It depends on your case whether multiple configs may exist with the same key, but if not, you should break out of the loop if a match is found (to avoid searching for others).

for i := range myconfig {
    if myconfig[i].Key == "key1" {
        // Found!
        break
    }
}

Also if this is a frequent operation, you should consider building a map from it which you can simply index, e.g.

// Build a config map:
confMap := map[string]string{}
for _, v := range myconfig {
    confMap[v.Key] = v.Value
}

// And then to find values by key:
if v, ok := confMap["key1"]; ok {
    // Found
}

Difference between using Throwable and Exception in a try catch

Throwable is super class of Exception as well as Error. In normal cases we should always catch sub-classes of Exception, so that the root cause doesn't get lost.

Only special cases where you see possibility of things going wrong which is not in control of your Java code, you should catch Error or Throwable.

I remember catching Throwable to flag that a native library is not loaded.

Apply multiple functions to multiple groupby columns

For the first part you can pass a dict of column names for keys and a list of functions for the values:

In [28]: df
Out[28]:
          A         B         C         D         E  GRP
0  0.395670  0.219560  0.600644  0.613445  0.242893    0
1  0.323911  0.464584  0.107215  0.204072  0.927325    0
2  0.321358  0.076037  0.166946  0.439661  0.914612    1
3  0.133466  0.447946  0.014815  0.130781  0.268290    1

In [26]: f = {'A':['sum','mean'], 'B':['prod']}

In [27]: df.groupby('GRP').agg(f)
Out[27]:
            A                   B
          sum      mean      prod
GRP
0    0.719580  0.359790  0.102004
1    0.454824  0.227412  0.034060

UPDATE 1:

Because the aggregate function works on Series, references to the other column names are lost. To get around this, you can reference the full dataframe and index it using the group indices within the lambda function.

Here's a hacky workaround:

In [67]: f = {'A':['sum','mean'], 'B':['prod'], 'D': lambda g: df.loc[g.index].E.sum()}

In [69]: df.groupby('GRP').agg(f)
Out[69]:
            A                   B         D
          sum      mean      prod  <lambda>
GRP
0    0.719580  0.359790  0.102004  1.170219
1    0.454824  0.227412  0.034060  1.182901

Here, the resultant 'D' column is made up of the summed 'E' values.

UPDATE 2:

Here's a method that I think will do everything you ask. First make a custom lambda function. Below, g references the group. When aggregating, g will be a Series. Passing g.index to df.ix[] selects the current group from df. I then test if column C is less than 0.5. The returned boolean series is passed to g[] which selects only those rows meeting the criteria.

In [95]: cust = lambda g: g[df.loc[g.index]['C'] < 0.5].sum()

In [96]: f = {'A':['sum','mean'], 'B':['prod'], 'D': {'my name': cust}}

In [97]: df.groupby('GRP').agg(f)
Out[97]:
            A                   B         D
          sum      mean      prod   my name
GRP
0    0.719580  0.359790  0.102004  0.204072
1    0.454824  0.227412  0.034060  0.570441

css 'pointer-events' property alternative for IE

I spent almost two days on finding the solution for this problem and I found this at last.

This uses javascript and jquery.

(GitHub) pointer_events_polyfill

This could use a javascript plug-in to be downloaded/copied. Just copy/download the codes from that site and save it as pointer_events_polyfill.js. Include that javascript to your site.

<script src="JS/pointer_events_polyfill.js></script>

Add this jquery scripts to your site

$(document).ready(function(){
    PointerEventsPolyfill.initialize({});
});

And don't forget to include your jquery plug-in.

It works! I can click elements under the transparent element. I'm using IE 10. I hope this can also work in IE 9 and below.

EDIT: Using this solution does not work when you click the textboxes below the transparent element. To solve this problem, I use focus when the user clicks on the textbox.

Javascript:

document.getElementById("theTextbox").focus();

JQuery:

$("#theTextbox").focus();

This lets you type the text into the textbox.

Does WGET timeout?

The default timeout is 900 second. You can specify different timeout.

-T seconds
--timeout=seconds

The default is to retry 20 times. You can specify different tries.

-t number
--tries=number

link: wget man document

How can I select all options of multi-select select box on click?

If you are using JQuery 1.9+ then above answers will not work in Firefox.

So here is a code for latest jquery which will work in all browsers.

See live demo

Here is the code

var select_ids = [];
$(document).ready(function(e) {
    $('select#myselect option').each(function(index, element) {
        select_ids.push($(this).val());
    })
});

function selectAll()
{
    $('select#myselect').val(select_ids);
}

function deSelectAll()
{
    $('select#myselect').val('');
}

Hope this will help you... :)

writing to serial port from linux command line

echo '\x12\x02'

will not be interpreted, and will literally write the string \x12\x02 (and append a newline) to the specified serial port. Instead use

echo -n ^R^B

which you can construct on the command line by typing CtrlVCtrlR and CtrlVCtrlB. Or it is easier to use an editor to type into a script file.

The stty command should work, unless another program is interfering. A common culprit is gpsd which looks for GPS devices being plugged in.

In Visual Basic how do you create a block comment

Not in VB.NET, you have to select all lines at then Edit, Advanced, Comment Selection menu, or a keyboard shortcut for that menu.

http://bytes.com/topic/visual-basic-net/answers/376760-how-block-comment

http://forums.asp.net/t/1011404.aspx/1

How do I create a file AND any folders, if the folders don't exist?

You will need to check both parts of the path (directory and filename) and create each if it does not exist.

Use File.Exists and Directory.Exists to find out whether they exist. Directory.CreateDirectory will create the whole path for you, so you only ever need to call that once if the directory does not exist, then simply create the file.

Error with multiple definitions of function

Here is a highly simplified but hopefully relevant view of what happens when you build your code in C++.

C++ splits the load of generating machine executable code in following different phases -

  1. Preprocessing - This is where any macros - #defines etc you might be using get expanded.

  2. Compiling - Each cpp file along with all the #included files in that file directly or indirectly (together called a compilation unit) is converted into machine readable object code.

    This is where C++ also checks that all functions defined (i.e. containing a body in { } e.g. void Foo( int x){ return Boo(x); }) are referring to other functions in a valid manner.

    The way it does that is by insisting that you provide at least a declaration of these other functions (e.g. void Boo(int); ) before you call it so it can check that you are calling it properly among other things. This can be done either directly in the cpp file where it is called or usually in an included header file.

    Note that only the machine code that corresponds to functions defined in this cpp and included files gets built as the object (binary) version of this compilation unit (e.g. Foo) and not the ones that are merely declared (e.g. Boo).

  3. Linking - This is the stage where C++ goes hunting for stuff declared and called in each compilation unit and links it to the places where it is getting called. Now if there was no definition found of this function the linker gives up and errors out. Similarly if it finds multiple definitions of the same function signature (essentially the name and parameter types it takes) it also errors out as it considers it ambiguous and doesn't want to pick one arbitrarily.

The latter is what is happening in your case. By doing a #include of the fun.cpp file, both fun.cpp and mainfile.cpp have a definition of funct() and the linker doesn't know which one to use in your program and is complaining about it.

The fix as Vaughn mentioned above is to not include the cpp file with the definition of funct() in mainfile.cpp and instead move the declaration of funct() in a separate header file and include that in mainline.cpp. This way the compiler will get the declaration of funct() to work with and the linker would get just one definition of funct() from fun.cpp and will use it with confidence.

How to define relative paths in Visual Studio Project?

I have used a syntax like this before:

$(ProjectDir)..\headers

or

..\headers

As other have pointed out, the starting directory is the one your project file is in(vcproj or vcxproj), not where your main code is located.

how to count the total number of lines in a text file using python

this one also gives the no.of lines in a file.

a=open('filename.txt','r')
l=a.read()
count=l.splitlines()
print(len(count))

Check if a list contains an item in Ansible

You do not need {{}} in when conditions. What you are searching for is:

- fail: msg="unsupported version"
  when: version not in acceptable_versions

Styling a input type=number

A little different to the other answers, using a similar concept but divs instead of pseudoclasses:

_x000D_
_x000D_
input {_x000D_
  position: absolute;_x000D_
  left: 10px;_x000D_
  top: 10px;_x000D_
  width: 50px;_x000D_
  height: 20px;_x000D_
  padding: 0px;_x000D_
  font-size: 14pt;_x000D_
  border: solid 0.5px #000;_x000D_
  z-index: 1;_x000D_
}_x000D_
_x000D_
.spinner-button {_x000D_
  position: absolute;_x000D_
  cursor: default;_x000D_
  z-index: 2;_x000D_
  background-color: #ccc;_x000D_
  width: 14.5px;_x000D_
  text-align: center;_x000D_
  margin: 0px;_x000D_
  pointer-events: none;_x000D_
  height: 10px;_x000D_
  line-height: 10px;_x000D_
}_x000D_
_x000D_
#inc-button {_x000D_
  left: 46px;_x000D_
  top: 10.5px;_x000D_
}_x000D_
_x000D_
#dec-button {_x000D_
  left: 46px;_x000D_
  top: 20.5px;_x000D_
}
_x000D_
<input type="number" value="0" min="0" max="100"/>_x000D_
<div id="inc-button" class="spinner-button">+</div>_x000D_
<div id="dec-button" class="spinner-button">-</div>
_x000D_
_x000D_
_x000D_

How can I load Partial view inside the view?

I had exactly the same problem as Leniel. I tried fixes suggested here and a dozen other places. The thing that finally worked for me was simply adding

@Scripts.Render("~/bundles/jquery")
@Scripts.Render("~/bundles/jqueryval")

to my layout...

How do you set autocommit in an SQL Server session?

You can turn autocommit ON by setting implicit_transactions OFF:

SET IMPLICIT_TRANSACTIONS OFF

When the setting is ON, it returns to implicit transaction mode. In implicit transaction mode, every change you make starts a transactions which you have to commit manually.

Maybe an example is clearer. This will write a change to the database:

SET IMPLICIT_TRANSACTIONS ON
UPDATE MyTable SET MyField = 1 WHERE MyId = 1
COMMIT TRANSACTION

This will not write a change to the database:

SET IMPLICIT_TRANSACTIONS ON
UPDATE MyTable SET MyField = 1 WHERE MyId = 1
ROLLBACK TRANSACTION

The following example will update a row, and then complain that there's no transaction to commit:

SET IMPLICIT_TRANSACTIONS OFF
UPDATE MyTable SET MyField = 1 WHERE MyId = 1
ROLLBACK TRANSACTION

Like Mitch Wheat said, autocommit is the default for Sql Server 2000 and up.

How to reference Microsoft.Office.Interop.Excel dll?

Use NuGet (VS 2013+):

The easiest way in any recent version of Visual Studio is to just use the NuGet package manager. (Even VS2013, with the NuGet Package Manager for Visual Studio 2013 extension.)

Right-click on "References" and choose "Manage NuGet Packages...", then just search for Excel.

enter image description here


VS 2012:

Older versions of VS didn't have access to NuGet.

  • Right-click on "References" and select "Add Reference".
  • Select "Extensions" on the left.
  • Look for Microsoft.Office.Interop.Excel.
    (Note that you can just type "excel" into the search box in the upper-right corner.)

VS2012/2013 References


VS 2008 / 2010:

  • Right-click on "References" and select "Add Reference".
  • Select the ".NET" tab.
  • Look for Microsoft.Office.Interop.Excel.

VS 2010 References

How to avoid java.util.ConcurrentModificationException when iterating through and removing elements from an ArrayList

One option is to modify the removeA method to this -

public void removeA(A a,Iterator<A> iterator) {
     iterator.remove(a);
     }

But this would mean your doSomething() should be able to pass the iterator to the remove method. Not a very good idea.

Can you do this in two step approach : In the first loop when you iterate over the list , instead of removing the selected elements , mark them as to be deleted. For this , you may simply copy these elements ( shallow copy ) into another List.

Then , once your iteration is done , simply do a removeAll from the first list all elements in the second list.

How to store arbitrary data for some HTML tags

A hack that's going to work with pretty much every possible browser is to use open classes like this: <a class='data\_articleid\_5' href="link/for/non-js-users.html>;

This is not all that elegant to the purists, but it's universally supported, standard-compliant, and very easy to manipulate. It really seems like the best possible method. If you serialize, modify, copy your tags, or do pretty much anything else, data will stay attached, copied etc.

The only problem is that you cannot store non-serializable objects that way, and there might be limits if you put something really huge there.

A second way is to use fake attributes like: <a articleid='5' href="link/for/non-js-users.html">

This is more elegant, but breaks standard, and I'm not 100% sure about support. Many browsers support it fully, I think IE6 supports JS access for it but not CSS selectors (which doesn't really matter here), maybe some browsers will be completely confused, you need to check it.

Doing funny things like serializing and deserializing would be even more dangerous.

Using ids to pure JS hash mostly works, except when you try to copy your tags. If you have tag <a href="..." id="link0">, copy it via standard JS methods, and then try to modify data attached to just one copy, the other copy will be modified.

It's not a problem if you don't copy tags, or use read only data. If you copy tags and they're modified you'll need to handle that manually.

Add URL link in CSS Background Image?

Using only CSS it is not possible at all to add links :) It is not possible to link a background-image, nor a part of it, using HTML/CSS. However, it can be staged using this method:

<div class="wrapWithBackgroundImage">
    <a href="#" class="invisibleLink"></a>
</div>

.wrapWithBackgroundImage {
    background-image: url(...);
}
.invisibleLink {
    display: block;
    left: 55px; top: 55px;
    position: absolute;
    height: 55px width: 55px;
}

no target device found android studio 2.1.1

This happened to me on android studio version 4 after doing an update to the IDE. The "invalidate caches and restart" option fixed it.

Mongoose: findOneAndUpdate doesn't return updated document

For whoever stumbled across this using ES6 / ES7 style with native promises, here is a pattern you can adopt...

const user = { id: 1, name: "Fart Face 3rd"};
const userUpdate = { name: "Pizza Face" };

try {
    user = await new Promise( ( resolve, reject ) => {
        User.update( { _id: user.id }, userUpdate, { upsert: true, new: true }, ( error, obj ) => {
            if( error ) {
                console.error( JSON.stringify( error ) );
                return reject( error );
            }

            resolve( obj );
        });
    })
} catch( error ) { /* set the world on fire */ }

How to remove all non-alpha numeric characters from a string in MySQL?

Probably a silly suggestion compared to others:

if(!preg_match("/^[a-zA-Z0-9]$/",$string)){
    $sortedString=preg_replace("/^[a-zA-Z0-9]+$/","",$string);
}

Reordering arrays

You could always use the sort method, if you don't know where the record is at present:

playlist.sort(function (a, b) {
    return a.artist == "Lalo Schifrin" 
               ? 1    // Move it down the list
               : 0;   // Keep it the same
});

Rounding BigDecimal to *always* have two decimal places

value = value.setScale(2, RoundingMode.CEILING)

How to install PyQt4 on Windows using pip?

install PyQt5 for Windows 10 and python 3.5+.

pip install PyQt5

How to search in an array with preg_match?

Use preg_grep

$array = preg_grep(
    '/(my\n+string\n+)/i',
    array( 'file' , 'my string  => name', 'this')
);

Join two data frames, select all columns from one and some columns from the other

Here is a solution that does not require a SQL context, but maintains the metadata of a DataFrame.

a = sc.parallelize([['a', 'foo'], ['b', 'hem'], ['c', 'haw']]).toDF(['a_id', 'extra'])
b = sc.parallelize([['p1', 'a'], ['p2', 'b'], ['p3', 'c']]).toDF(["other", "b_id"])

c = a.join(b, a.a_id == b.b_id)

Then, c.show() yields:

+----+-----+-----+----+
|a_id|extra|other|b_id|
+----+-----+-----+----+
|   a|  foo|   p1|   a|
|   b|  hem|   p2|   b|
|   c|  haw|   p3|   c|
+----+-----+-----+----+

HTTP Error 500.22 - Internal Server Error (An ASP.NET setting has been detected that does not apply in Integrated managed pipeline mode.)

I have a similar problem with IIS 7, Win 7 Enterprise Pack. I have changed the application Pool as in @Kirk answer :

Change the Application Pool mode to one that has Classic pipeline enabled".but no luck for me.

Adding one more step worked for me. I have changed the my website's .NET Frameworkis v2.0 to .NET Frameworkis v4.0. in ApplicationPool

Error: [ng:areq] from angular controller

In my case I included app.js below the controller while app.js should include above any controller like

<script src="js/app.js"></script> 
<script src="js/controllers/mainCtrl.js"></script>

How can I find the maximum value and its index in array in MATLAB?

For a matrix you can use this:

[M,I] = max(A(:))

I is the index of A(:) containing the largest element.

Now, use the ind2sub function to extract the row and column indices of A corresponding to the largest element.

[I_row, I_col] = ind2sub(size(A),I)

source: https://www.mathworks.com/help/matlab/ref/max.html

Most concise way to convert a Set<T> to a List<T>

List<String> list = new ArrayList<String>(listOfTopicAuthors);

How to create a Date in SQL Server given the Day, Month and Year as Integers

For SQL Server 2008 users, I made a custom function:

CREATE FUNCTION sql2012_datefromparts
(   
    @Year int, @Month int, @Day int
)
RETURNS DATETIME
AS
BEGIN
    RETURN convert(datetime,convert(varchar,@year)+right('0'+convert(varchar,@month),2)+right('0'+convert(varchar,@day),2)) 
END
GO

To use it:

DECLARE @day int=29, @month int=10, @year int=1971
SELECT dbo.sql2012_datefromparts(@year,@month,@day)

How to avoid precompiled headers

try to add #include "stdafx.h" before #include "iostream"

Add Twitter Bootstrap icon to Input box

Bootstrap 4.x

With Bootstrap 4 (and Font Awesome), we still can use the input-group wrapper around our form-control element, and now we can use an input-group-append (or input-group-prepend) wrapper with an input-group-text to get the job done:

<div class="input-group mb-3">
  <input type="text" class="form-control" placeholder="Search" aria-label="Search" aria-describedby="my-search">
  <div class="input-group-append">
    <span class="input-group-text" id="my-search"><i class="fas fa-filter"></i></span>
  </div>
</div>

It will look something like this (thanks to KyleMit for the screenshot):

enter image description here

Learn more by visiting the Input group documentation.

Under what circumstances can I call findViewById with an Options Menu / Action Bar item?

I am trying to obtain a handle on one of the views in the Action Bar

I will assume that you mean something established via android:actionLayout in your <item> element of your <menu> resource.

I have tried calling findViewById(R.id.menu_item)

To retrieve the View associated with your android:actionLayout, call findItem() on the Menu to retrieve the MenuItem, then call getActionView() on the MenuItem. This can be done any time after you have inflated the menu resource.

TempData keep() vs peek()

don't they both keep a value for another request?

Yes they do, but when the first one is void, the second one returns and object:

public void Keep(string key)
{
    _retainedKeys.Add(key); // just adds the key to the collection for retention
}

public object Peek(string key)
{
    object value;
    _data.TryGetValue(key, out value);
    return value; // returns an object without marking it for deletion
}

How to my "exe" from PyCharm project

You cannot directly save a Python file as an exe and expect it to work -- the computer cannot automatically understand whatever code you happened to type in a text file. Instead, you need to use another program to transform your Python code into an exe.

I recommend using a program like Pyinstaller. It essentially takes the Python interpreter and bundles it with your script to turn it into a standalone exe that can be run on arbitrary computers that don't have Python installed (typically Windows computers, since Linux tends to come pre-installed with Python).

To install it, you can either download it from the linked website or use the command:

pip install pyinstaller

...from the command line. Then, for the most part, you simply navigate to the folder containing your source code via the command line and run:

pyinstaller myscript.py

You can find more information about how to use Pyinstaller and customize the build process via the documentation.


You don't necessarily have to use Pyinstaller, though. Here's a comparison of different programs that can be used to turn your Python code into an executable.

Making view resize to its parent when added with addSubview

that's all you need

childView.frame = parentView.bounds