Programs & Examples On #Native sql

Send HTTP POST message in ASP.NET Core using HttpClient PostAsJsonAsync

I use this class:

public class JsonContent : StringContent
{
    public JsonContent(object obj) :
        base(JsonConvert.SerializeObject(obj), Encoding.UTF8, "application/json")
    { }
}

Sample of usage:

new HttpClient().PostAsync("http://...", new JsonContent(new { x = 1, y = 2 }));

What is PAGEIOLATCH_SH wait type in SQL Server?

From Microsoft documentation:

PAGEIOLATCH_SH

Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Shared mode. Long waits may indicate problems with the disk subsystem.

In practice, this almost always happens due to large scans over big tables. It almost never happens in queries that use indexes efficiently.

If your query is like this:

Select * from <table> where <col1> = <value> order by <PrimaryKey>

, check that you have a composite index on (col1, col_primary_key).

If you don't have one, then you'll need either a full INDEX SCAN if the PRIMARY KEY is chosen, or a SORT if an index on col1 is chosen.

Both of them are very disk I/O consuming operations on large tables.

Consistency of hashCode() on a Java string

Another (!) issue to worry about is the possible change of implementation between early/late versions of Java. I don't believe the implementation details are set in stone, and so potentially an upgrade to a future Java version could cause problems.

Bottom line is, I wouldn't rely on the implementation of hashCode().

Perhaps you can highlight what problem you're actually trying to solve by using this mechanism, and that will highlight a more suitable approach.

jQuery .slideRight effect

Another solution is by using .animate() and appropriate CSS.

e.g.

   $('#mydiv').animate({ marginLeft: "100%"} , 4000);

JS Fiddle

How do I spool to a CSV formatted file using SQLPLUS?

I have once written a little SQL*Plus script that uses dbms_sql and dbms_output to create a csv (actually an ssv). You can find it on my githup repository.

Use jQuery to navigate away from page

window.location = myUrl;

Anyway, this is not jQuery: it's plain javascript

Accessing all items in the JToken

In addition to the accepted answer I would like to give an answer that shows how to iterate directly over the Newtonsoft collections. It uses less code and I'm guessing its more efficient as it doesn't involve converting the collections.

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
//Parse the data
JObject my_obj = JsonConvert.DeserializeObject<JObject>(your_json);

foreach (KeyValuePair<string, JToken> sub_obj in (JObject)my_obj["ADDRESS_MAP"])
{
    Console.WriteLine(sub_obj.Key);
}

I started doing this myself because JsonConvert automatically deserializes nested objects as JToken (which are JObject, JValue, or JArray underneath I think).

I think the parsing works according to the following principles:

  • Every object is abstracted as a JToken

  • Cast to JObject where you expect a Dictionary

  • Cast to JValue if the JToken represents a terminal node and is a value

  • Cast to JArray if its an array

  • JValue.Value gives you the .NET type you need

How to restart remote MySQL server running on Ubuntu linux?

  • To restart mysql use this command

sudo service mysql restart

Or

sudo restart mysql

Reference

/bin/sh: pushd: not found

add

SHELL := /bin/bash

at the top of your makefile I have found it on another question How can I use Bash syntax in Makefile targets?

What is the difference between a Shared Project and a Class Library in Visual Studio 2015?

The difference between a shared project and a class library is that the latter is compiled and the unit of reuse is the assembly.

Whereas with the former, the unit of reuse is the source code, and the shared code is incorporated into each assembly that references the shared project.

This can be useful when you want to create separate assemblies that target specific platforms but still have code that should be shared.

See also here:

The shared project reference shows up under the References node in the Solution Explorer, but the code and assets in the shared project are treated as if they were files linked into the main project.


In previous versions of Visual Studio1, you could share source code between projects by Add -> Existing Item and then choosing to Link. But this was kind of clunky and each separate source file had to be selected individually. With the move to supporting multiple disparate platforms (iOS, Android, etc), they decided to make it easier to share source between projects by adding the concept of Shared Projects.


1 This question and my answer (up until now) suggest that Shared Projects was a new feature in Visual Studio 2015. In fact, they made their debut in Visual Studio 2013 Update 2

Why should we include ttf, eot, woff, svg,... in a font-face

Answer in 2019:

Only use WOFF2, or if you need legacy support, WOFF. Do not use any other format

(svg and eot are dead formats, ttf and otf are full system fonts, and should not be used for web purposes)

Original answer from 2012:

In short, font-face is very old, but only recently has been supported by more than IE.

  • eot is needed for Internet Explorers that are older than IE9 - they invented the spec, but eot was a proprietary solution.

  • ttf and otf are normal old fonts, so some people got annoyed that this meant anyone could download expensive-to-license fonts for free.

  • Time passes, SVG 1.1 adds a "fonts" chapter that explains how to model a font purely using SVG markup, and people start to use it. More time passes and it turns out that they are absolutely terrible compared to just a normal font format, and SVG 2 wisely removes the entire chapter again.

  • Then, woff gets invented by people with quite a bit of domain knowledge, which makes it possible to host fonts in a way that throws away bits that are critically important for system installation, but irrelevant for the web (making people worried about piracy happy) and allows for internal compression to better suit the needs of the web (making users and hosts happy). This becomes the preferred format.

  • 2019 edit A few years later, woff2 gets drafted and accepted, which improves the compression, leading to even smaller files, along with the ability to load a single font "in parts" so that a font that supports 20 scripts can be stored as "chunks" on disk instead, with browsers automatically able to load the font "in parts" as needed, rather than needing to transfer the entire font up front, further improving the typesetting experience.

If you don't want to support IE 8 and lower, and iOS 4 and lower, and android 4.3 or earlier, then you can just use WOFF (and WOFF2, a more highly compressed WOFF, for the newest browsers that support it.)

@font-face {
  font-family: 'MyWebFont';
  src:  url('myfont.woff2') format('woff2'),
        url('myfont.woff') format('woff');
}

Support for woff can be checked at http://caniuse.com/woff
Support for woff2 can be checked at http://caniuse.com/woff2

date format yyyy-MM-ddTHH:mm:ssZ

"o" format is different for DateTime vs DateTimeOffset :(

DateTime.UtcNow.ToString("o") -> "2016-03-09T03:30:25.1263499Z"

DateTimeOffset.UtcNow.ToString("o") -> "2016-03-09T03:30:46.7775027+00:00"

My final answer is

DateTimeOffset.UtcDateTime.ToString("o")   //for DateTimeOffset type
DateTime.UtcNow.ToString("o")              //for DateTime type

Psexec "run as (remote) admin"

Use psexec -s

The s switch will cause it to run under system account which is the same as running an elevated admin prompt. just used it to enable WinRM remotely.

Node Multer unexpected field

In my scenario this was happening because I renamed a parameter in swagger.yaml but did not reload the docs page.

Hence I was trying the API with an unexpected input parameter.
Long story short, F5 is my friend.

CodeIgniter 500 Internal Server Error

Make sure your root index.php file has the correct permission, its permission must be 0755 or 0644

Fade Effect on Link Hover?

Nowadays people are just using CSS3 transitions because it's a lot easier than messing with JS, browser support is reasonably good and it's merely cosmetic so it doesn't matter if it doesn't work.

Something like this gets the job done:

a {
  color:blue;
  /* First we need to help some browsers along for this to work.
     Just because a vendor prefix is there, doesn't mean it will
     work in a browser made by that vendor either, it's just for
     future-proofing purposes I guess. */
  -o-transition:.5s;
  -ms-transition:.5s;
  -moz-transition:.5s;
  -webkit-transition:.5s;
  /* ...and now for the proper property */
  transition:.5s;
}
a:hover { color:red; }

You can also transition specific CSS properties with different timings and easing functions by separating each declaration with a comma, like so:

a {
  color:blue; background:white;
  -o-transition:color .2s ease-out, background 1s ease-in;
  -ms-transition:color .2s ease-out, background 1s ease-in;
  -moz-transition:color .2s ease-out, background 1s ease-in;
  -webkit-transition:color .2s ease-out, background 1s ease-in;
  /* ...and now override with proper CSS property */
  transition:color .2s ease-out, background 1s ease-in;
}
a:hover { color:red; background:yellow; }

Demo here

Text-decoration: none not working

You have a block element (div) inside an inline element (a). This works in HTML 5, but not HTML 4. Thus also only browsers that actually support HTML 5.

When browsers encounter invalid markup, they will try to fix it, but different browsers will do that in different ways, so the result varies. Some browsers will move the block element outside the inline element, some will ignore it.

Error inflating class android.support.design.widget.NavigationView

In my case, I had the same error when I run the app in kitkat API 19 version device. I figured out the problem; I had some drawable resources which was in the drawable-v21 directory (Which is used for versions from API 21 Lollipop). I just put the same resources in the "Drawable" folder to work with the version below API 21. It works. You can put it on the corresponding directory

sending mail from Batch file

PowerShell comes with a built in command for it. So running directly from a .bat file:

powershell -ExecutionPolicy ByPass -Command Send-MailMessage ^
    -SmtpServer server.address.name ^
    -To [email protected] ^
    -From [email protected] ^
    -Subject Testing ^
    -Body 123

NB -ExecutionPolicy ByPass is only needed if you haven't set up permissions for running PS from CMD

Also for those looking to call it from within powershell, drop everything before -Command [inclusive], and ` will be your escape character (not ^)

What's the best/easiest GUI Library for Ruby?

Tk is available for Ruby. Some nice examples (in Ruby, Perl and Tcl) can be found at http://www.tkdocs.com/

PostgreSQL CASE ... END with multiple conditions

This kind of code perhaps should work for You

SELECT
 *,
 CASE
  WHEN (pvc IS NULL OR pvc = '') AND (datepose < 1980) THEN '01'
  WHEN (pvc IS NULL OR pvc = '') AND (datepose >= 1980) THEN '02'
  WHEN (pvc IS NULL OR pvc = '') AND (datepose IS NULL OR datepose = 0) THEN '03'
  ELSE '00'
 END AS modifiedpvc
FROM my_table;


 gid | datepose | pvc | modifiedpvc 
-----+----------+-----+-------------
   1 |     1961 | 01  | 00
   2 |     1949 |     | 01
   3 |     1990 | 02  | 00
   1 |     1981 |     | 02
   1 |          | 03  | 00
   1 |          |     | 03
(6 rows)

dbms_lob.getlength() vs. length() to find blob size in oracle

length and dbms_lob.getlength return the number of characters when applied to a CLOB (Character LOB). When applied to a BLOB (Binary LOB), dbms_lob.getlength will return the number of bytes, which may differ from the number of characters in a multi-byte character set.

As the documentation doesn't specify what happens when you apply length on a BLOB, I would advise against using it in that case. If you want the number of bytes in a BLOB, use dbms_lob.getlength.

WPF User Control Parent

This didn't work for me, as it went too far up the tree, and got the absolute root window for the entire application:

Window parentWindow = Window.GetWindow(userControlReference);

However, this worked to get the immediate window:

DependencyObject parent = uiElement;
int avoidInfiniteLoop = 0;
while ((parent is Window)==false)
{
    parent = VisualTreeHelper.GetParent(parent);
    avoidInfiniteLoop++;
    if (avoidInfiniteLoop == 1000)
    {
        // Something is wrong - we could not find the parent window.
        break;
    }
}
Window window = parent as Window;
window.DragMove();

Difference between const reference and normal parameter

The first method passes n by value, i.e. a copy of n is sent to the function. The second one passes n by reference which basically means that a pointer to the n with which the function is called is sent to the function.

For integral types like int it doesn't make much sense to pass as a const reference since the size of the reference is usually the same as the size of the reference (the pointer). In the cases where making a copy is expensive it's usually best to pass by const reference.

Usage of sys.stdout.flush() method

import sys
for x in range(10000):
    print "HAPPY >> %s <<\r" % str(x),
    sys.stdout.flush()

Set language for syntax highlighting in Visual Studio Code

Another reason why people might struggle to get Syntax Highlighting working is because they don't have the appropriate syntax package installed. While some default syntax packages come pre-installed (like Swift, C, JS, CSS), others may not be available.

To solve this you can Cmd + Shift + P ? "install Extensions" and look for the language you want to add, say "Scala".

enter image description here

Find the suitable Syntax package, install it and reload. This will pick up the correct syntax for your files with the predefined extension, i.e. .scala in this case.

On top of that you might want VS Code to treat all files with certain custom extensions as your preferred language of choice. Let's say you want to highlight all *.es files as JavaScript, then just open "User Settings" (Cmd + Shift + P ? "User Settings") and configure your custom files association like so:

  "files.associations": {
    "*.es": "javascript"
  },

AttributeError: 'str' object has no attribute

The problem is in your playerMovement method. You are creating the string name of your room variables (ID1, ID2, ID3):

letsago = "ID" + str(self.dirDesc.values())

However, what you create is just a str. It is not the variable. Plus, I do not think it is doing what you think its doing:

>>>str({'a':1}.values())
'dict_values([1])'

If you REALLY needed to find the variable this way, you could use the eval function:

>>>foo = 'Hello World!'
>>>eval('foo')
'Hello World!'

or the globals function:

class Foo(object):
    def __init__(self):
        super(Foo, self).__init__()
    def test(self, name):
        print(globals()[name])

foo = Foo()
bar = 'Hello World!'
foo.text('bar')

However, instead I would strongly recommend you rethink you class(es). Your userInterface class is essentially a Room. It shouldn't handle player movement. This should be within another class, maybe GameManager or something like that.

Troubleshooting "Illegal mix of collations" error in mysql

Solution if literals are involved.

I am using Pentaho Data Integration and dont get to specify the sql syntax. Using a very simple DB lookup gave the error "Illegal mix of collations (cp850_general_ci,COERCIBLE) and (latin1_swedish_ci,COERCIBLE) for operation '='"

The generated code was "SELECT DATA_DATE AS latest_DATA_DATE FROM hr_cc_normalised_data_date_v WHERE PSEUDO_KEY = ?"

Cutting the story short the lookup was to a view and when I issued

mysql> show full columns from hr_cc_normalised_data_date_v;
+------------+------------+-------------------+------+-----+
| Field      | Type       | Collation         | Null | Key |
+------------+------------+-------------------+------+-----+
| PSEUDO_KEY | varchar(1) | cp850_general_ci  | NO   |     |
| DATA_DATE  | varchar(8) | latin1_general_cs | YES  |     |
+------------+------------+-------------------+------+-----+

which explains where the 'cp850_general_ci' comes from.

The view was simply created with 'SELECT 'X',......' According to the manual literals like this should inherit their character set and collation from server settings which were correctly defined as 'latin1' and 'latin1_general_cs' as this clearly did not happen I forced it in the creation of the view

CREATE OR REPLACE VIEW hr_cc_normalised_data_date_v AS
SELECT convert('X' using latin1) COLLATE latin1_general_cs        AS PSEUDO_KEY
    ,  DATA_DATE
FROM HR_COSTCENTRE_NORMALISED_mV
LIMIT 1;

now it shows latin1_general_cs for both columns and the error has gone away. :)

Value Change Listener to JTextField

The usual answer to this is "use a DocumentListener". However, I always find that interface cumbersome. Truthfully the interface is over-engineered. It has three methods, for insertion, removal, and replacement of text, when it only needs one method: replacement. (An insertion can be viewed as a replacement of no text with some text, and a removal can be viewed as a replacement of some text with no text.)

Usually all you want is to know is when the text in the box has changed, so a typical DocumentListener implementation has the three methods calling one method.

Therefore I made the following utility method, which lets you use a simpler ChangeListener rather than a DocumentListener. (It uses Java 8's lambda syntax, but you can adapt it for old Java if needed.)

/**
 * Installs a listener to receive notification when the text of any
 * {@code JTextComponent} is changed. Internally, it installs a
 * {@link DocumentListener} on the text component's {@link Document},
 * and a {@link PropertyChangeListener} on the text component to detect
 * if the {@code Document} itself is replaced.
 * 
 * @param text any text component, such as a {@link JTextField}
 *        or {@link JTextArea}
 * @param changeListener a listener to receieve {@link ChangeEvent}s
 *        when the text is changed; the source object for the events
 *        will be the text component
 * @throws NullPointerException if either parameter is null
 */
public static void addChangeListener(JTextComponent text, ChangeListener changeListener) {
    Objects.requireNonNull(text);
    Objects.requireNonNull(changeListener);
    DocumentListener dl = new DocumentListener() {
        private int lastChange = 0, lastNotifiedChange = 0;

        @Override
        public void insertUpdate(DocumentEvent e) {
            changedUpdate(e);
        }

        @Override
        public void removeUpdate(DocumentEvent e) {
            changedUpdate(e);
        }

        @Override
        public void changedUpdate(DocumentEvent e) {
            lastChange++;
            SwingUtilities.invokeLater(() -> {
                if (lastNotifiedChange != lastChange) {
                    lastNotifiedChange = lastChange;
                    changeListener.stateChanged(new ChangeEvent(text));
                }
            });
        }
    };
    text.addPropertyChangeListener("document", (PropertyChangeEvent e) -> {
        Document d1 = (Document)e.getOldValue();
        Document d2 = (Document)e.getNewValue();
        if (d1 != null) d1.removeDocumentListener(dl);
        if (d2 != null) d2.addDocumentListener(dl);
        dl.changedUpdate(null);
    });
    Document d = text.getDocument();
    if (d != null) d.addDocumentListener(dl);
}

Unlike with adding a listener directly to the document, this handles the (uncommon) case that you install a new document object on a text component. Additionally, it works around the problem mentioned in Jean-Marc Astesana's answer, where the document sometimes fires more events than it needs to.

Anyway, this method lets you replace annoying code which looks like this:

someTextBox.getDocument().addDocumentListener(new DocumentListener() {
    @Override
    public void insertUpdate(DocumentEvent e) {
        doSomething();
    }

    @Override
    public void removeUpdate(DocumentEvent e) {
        doSomething();
    }

    @Override
    public void changedUpdate(DocumentEvent e) {
        doSomething();
    }
});

With:

addChangeListener(someTextBox, e -> doSomething());

Code released to public domain. Have fun!

How to create a Custom Dialog box in android?

Add the below theme in values -> style.xml

<style name="Theme_Dialog" parent="android:Theme.Light">
     <item name="android:windowNoTitle">true</item>
     <item name="android:windowBackground">@android:color/transparent</item>
</style>

Use this theme in your onCreateDialog method like this:

Dialog dialog = new Dialog(FlightBookActivity.this,R.style.Theme_Dialog);

Define your dialog layout including title bar in the xml file and set that xml file like this:

dialog.setContentView(R.layout.your_dialog_layout);

PHP - include a php file and also send query parameters

An include is just like a code insertion. You get in your included code the exact same variables you have in your base code. So you can do this in your main file :

<?
    if ($condition == true)
    {
        $id = 12345;
        include 'myFile.php';
    }
?>

And in "myFile.php" :

<?
    echo 'My id is : ' . $id . '!';
?>

This will output :

My id is 12345 !

C function that counts lines in file

I don't see anything immediately obvious as to what would cause a segmentation fault. My only suspicion is that your code expects to get a filename as a parameter when you run it, but if you don't pass it, it will attempt to reference one, anyway.

Accessing argv[1] when it doesn't exist would cause a segmentation fault. It's generally good practice to check the number of arguments before trying to reference them. You can do this by using the following function prototype for main(), and checking that argc is greater than 1 (simply, it will indicate the number entries in argv).

int main(int argc, char** argv)

The best way to figure out what causes a segfault in general is to use a debugger. If you're in Visual Studio, put a breakpoint at the top of your main function and then choose Run with debugging instead of "Run without debugging" when you start the program. It will stop execution at the top, and let you step line-by-line until you see a problem.

If you're in Linux, you can just grab the core file (it will have "core" in the name) and load that with gdb (GNU Debugger). It can give you a stack dump which will point you straight to the line that caused the segmentation fault to occur.

EDIT: I see you changed your question and code. So this answer probably isn't useful anymore, but I'll leave it as it's good advice anyway, and see if I can address the modified question, shortly).

How to stop an app on Heroku?

If you are using eclipse plugin, double click on the app-name in My Heroku Applications. In Processes tab, press Scale Button. A small window will pop-up. Increase/decrease the count and just say OK.

Are there any standard exit status codes in Linux?

Standard Unix exit codes are defined by sysexits.h, as another poster mentioned. The same exit codes are used by portable libraries such as Poco - here is a list of them:

http://pocoproject.org/docs/Poco.Util.Application.html#16218

A signal 11 is a SIGSEGV (segment violation) signal, which is different from a return code. This signal is generated by the kernel in response to a bad page access, which causes the program to terminate. A list of signals can be found in the signal man page (run "man signal").

VBA: Counting rows in a table (list object)

You can use this:

    Range("MyTable[#Data]").Rows.Count

You have to distinguish between a table which has either one row of data or no data, as the previous code will return "1" for both cases. Use this to test for an empty table:

    If WorksheetFunction.CountA(Range("MyTable[#Data]"))

Right align text in android TextView

In my case, I was using Relative Layout for a emptyString

After struggling on this for an hour. Only this worked for me:

android:layout_toRightOf="@id/welcome"
android:layout_toEndOf="@id/welcome"
android:layout_alignBaseline="@id/welcome"

layout_toRightOf or layout_toEndOf both works, but to support it better, I used both.

To make it more clear:

This was what I was trying to do:

enter image description here

And this was the emulator's output

enter image description here

Layout:

<TextView
    android:id="@+id/welcome"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:text="Welcome "
    android:textSize="16sp" />
<TextView
    android:id="@+id/username"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@id/welcome"
    android:layout_toRightOf="@id/welcome"
    android:text="@string/emptyString"
    android:textSize="16sp" />

Notice that:

  1. android:layout_width="wrap_content" works
  2. Gravity is not used

Android: how to parse URL String with spaces to URI object?

I wrote this function:

public static String encode(@NonNull String uriString) {
    if (TextUtils.isEmpty(uriString)) {
        Assert.fail("Uri string cannot be empty!");
        return uriString;
    }
    // getQueryParameterNames is not exist then cannot iterate on queries
    if (Build.VERSION.SDK_INT < 11) {
        return uriString;
    }

    // Check if uri has valid characters
    // See https://tools.ietf.org/html/rfc3986
    Pattern allowedUrlCharacters = Pattern.compile("([A-Za-z0-9_.~:/?\\#\\[\\]@!$&'()*+,;" +
            "=-]|%[0-9a-fA-F]{2})+");
    Matcher matcher = allowedUrlCharacters.matcher(uriString);
    String validUri = null;
    if (matcher.find()) {
        validUri = matcher.group();
    }
    if (TextUtils.isEmpty(validUri) || uriString.length() == validUri.length()) {
        return uriString;
    }

    // The uriString is not encoded. Then recreate the uri and encode it this time
    Uri uri = Uri.parse(uriString);
    Uri.Builder uriBuilder = new Uri.Builder()
            .scheme(uri.getScheme())
            .authority(uri.getAuthority());
    for (String path : uri.getPathSegments()) {
        uriBuilder.appendPath(path);
    }
    for (String key : uri.getQueryParameterNames()) {
        uriBuilder.appendQueryParameter(key, uri.getQueryParameter(key));
    }
    String correctUrl = uriBuilder.build().toString();
    return correctUrl;
}

.NET HttpClient. How to POST string value?

Below is example to call synchronously but you can easily change to async by using await-sync:

var pairs = new List<KeyValuePair<string, string>>
            {
                new KeyValuePair<string, string>("login", "abc")
            };

var content = new FormUrlEncodedContent(pairs);

var client = new HttpClient {BaseAddress = new Uri("http://localhost:6740")};

    // call sync
var response = client.PostAsync("/api/membership/exist", content).Result; 
if (response.IsSuccessStatusCode)
{
}

How can I check if a date is the same day as datetime.today()?

all(getattr(someTime,x)==getattr(today(),x) for x in ['year','month','day'])

One should compare using .date(), but I leave this method as an example in case one wanted to, for example, compare things by month or by minute, etc.

How can I pass a list as a command-line argument with argparse?

I think the most elegant solution is to pass a lambda function to "type", as mentioned by Chepner. In addition to this, if you do not know beforehand what the delimiter of your list will be, you can also pass multiple delimiters to re.split:

# python3 test.py -l "abc xyz, 123"

import re
import argparse

parser = argparse.ArgumentParser(description='Process a list.')
parser.add_argument('-l', '--list',
                    type=lambda s: re.split(' |, ', s),
                    required=True,
                    help='comma or space delimited list of characters')

args = parser.parse_args()
print(args.list)


# Output: ['abc', 'xyz', '123']

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

This javascript is nice that it doesn't open a new window or tab.

window.location.assign(url);

CSS Box Shadow Bottom Only

You can use two elements, one inside the other, and give the outer one overflow: hidden and a width equal to the inner element together with a bottom padding so that the shadow on all the other sides are "cut off"

#outer {
    width: 100px;
    overflow: hidden;
    padding-bottom: 10px;
}

#outer > div {
    width: 100px;
    height: 100px;
    background: orange;

    -moz-box-shadow: 0 4px 4px rgba(0, 0, 0, 0.4);
    -webkit-box-shadow: 0 4px 4px rgba(0, 0, 0, 0.4);
    box-shadow: 0 4px 4px rgba(0, 0, 0, 0.4);
}

Alternatively, float the outer element to cause it to shrink to the size of the inner element. See: http://jsfiddle.net/QJPd5/1/

Creating self signed certificate for domain and subdomains - NET::ERR_CERT_COMMON_NAME_INVALID

As Rahul stated, it is a common Chrome and an OSX bug. I was having similar issues in the past. In fact I finally got tired of making the 2 [yes I know it is not many] additional clicks when testing a local site for work.

As for a possible workaround to this issue [using Windows], I would using one of the many self signing certificate utilities available.

Recommended Steps:

  1. Create a Self Signed Cert
  2. Import Certificate into Windows Certificate Manager
  3. Import Certificate in Chrome Certificate Manager
    NOTE: Step 3 will resolve the issue experienced once Google addresses the bug...considering the time in has been stale there is no ETA in the foreseeable future.**

    As much as I prefer to use Chrome for development, I have found myself in Firefox Developer Edition lately. which does not have this issue.

    Hope this helps :)

How to get the date 7 days earlier date from current date in Java

Use the Calendar-API:

// get Calendar instance
Calendar cal = Calendar.getInstance();
cal.setTime(new Date());

// substract 7 days
// If we give 7 there it will give 8 days back
cal.set(Calendar.DAY_OF_MONTH, cal.get(Calendar.DAY_OF_MONTH)-6);

// convert to date
Date myDate = cal.getTime();

Hope this helps. Have Fun!

display Java.util.Date in a specific format

You can use simple date format in Java using the code below

SimpleDateFormat simpledatafo = new SimpleDateFormat("dd/MM/yyyy");
Date newDate = new Date();
String expectedDate= simpledatafo.format(newDate);

Count frequency of words in a list and sort by frequency

Here is code support your question is_char() check for validate string count those strings alone, Hashmap is dictionary in python

def is_word(word):
   cnt =0
   for c in word:

      if 'a' <= c <='z' or 'A' <= c <= 'Z' or '0' <= c <= '9' or c == '$':
          cnt +=1
   if cnt==len(word):
      return True
  return False

def words_freq(s):
  d={}
  for i in s.split():
    if is_word(i):
        if i in d:
            d[i] +=1
        else:
            d[i] = 1
   return d

 print(words_freq('the the sky$ is blue not green'))

Connecting client to server using Socket.io

Have you tried loading the socket.io script not from a relative URL?

You're using:

<script src="socket.io/socket.io.js"></script>

And:

socket.connect('http://127.0.0.1:8080');

You should try:

<script src="http://localhost:8080/socket.io/socket.io.js"></script>

And:

socket.connect('http://localhost:8080');

Switch localhost:8080 with whatever fits your current setup.

Also, depending on your setup, you may have some issues communicating to the server when loading the client page from a different domain (same-origin policy). This can be overcome in different ways (outside of the scope of this answer, google/SO it).

Why is null an object and what's the difference between null and undefined?

typeof null;      // object
typeof undefined; // undefined

The value null represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.

var x = null;
var y;

x is declared & defined as null

y is declared but not defined. It is declared with no value so it is undefined.

z is not declared so would also be undefined if you attempted to use z.

Get max and min value from array in JavaScript

if you have "scattered" (not inside an array) values you can use:

var max_value = Math.max(val1, val2, val3, val4, val5);

Why .NET String is immutable?

There are five common ways by which a class data store data that cannot be modified outside the storing class' control:

  1. As value-type primitives
  2. By holding a freely-shareable reference to class object whose properties of interest are all immutable
  3. By holding a reference to a mutable class object that will never be exposed to anything that might mutate any properties of interest
  4. As a struct, whether "mutable" or "immutable", all of whose fields are of types #1-#4 (not #5).
  5. By holding the only extant copy of a reference to an object whose properties can only be mutated via that reference.

Because strings are of variable length, they cannot be value-type primitives, nor can their character data be stored in a struct. Among the remaining choices, the only one which wouldn't require that strings' character data be stored in some kind of immutable object would be #5. While it would be possible to design a framework around option #5, that choice would require that any code which wanted a copy of a string that couldn't be changed outside its control would have to make a private copy for itself. While it hardly be impossible to do that, the amount of extra code required to do that, and the amount of extra run-time processing necessary to make defensive copies of everything, would far outweigh the slight benefits that could come from having string be mutable, especially given that there is a mutable string type (System.Text.StringBuilder) which accomplishes 99% of what could be accomplished with a mutable string.

setImmediate vs. nextTick

I think I can illustrate this quite nicely. Since nextTick is called at the end of the current operation, calling it recursively can end up blocking the event loop from continuing. setImmediate solves this by firing in the check phase of the event loop, allowing event loop to continue normally.

   +-----------------------+
+->¦        timers         ¦
¦  +-----------------------+
¦  +-----------------------+
¦  ¦     I/O callbacks     ¦
¦  +-----------------------+
¦  +-----------------------+
¦  ¦     idle, prepare     ¦
¦  +-----------------------+      +---------------+
¦  +-----------------------+      ¦   incoming:   ¦
¦  ¦         poll          ¦<-----¦  connections, ¦
¦  +-----------------------+      ¦   data, etc.  ¦
¦  +-----------------------+      +---------------+
¦  ¦        check          ¦
¦  +-----------------------+
¦  +-----------------------+
+--¦    close callbacks    ¦
   +-----------------------+

source: https://nodejs.org/en/docs/guides/event-loop-timers-and-nexttick/

Notice that the check phase is immediately after the poll phase. This is because the poll phase and I/O callbacks are the most likely places your calls to setImmediate are going to run. So ideally most of those calls will actually be pretty immediate, just not as immediate as nextTick which is checked after every operation and technically exists outside of the event loop.

Let's take a look at a little example of the difference between setImmediate and process.nextTick:

function step(iteration) {
  if (iteration === 10) return;
  setImmediate(() => {
    console.log(`setImmediate iteration: ${iteration}`);
    step(iteration + 1); // Recursive call from setImmediate handler.
  });
  process.nextTick(() => {
    console.log(`nextTick iteration: ${iteration}`);
  });
}
step(0);

Let's say we just ran this program and are stepping through the first iteration of the event loop. It will call into the step function with iteration zero. It will then register two handlers, one for setImmediate and one for process.nextTick. We then recursively call this function from the setImmediate handler which will run in the next check phase. The nextTick handler will run at the end of the current operation interrupting the event loop, so even though it was registered second it will actually run first.

The order ends up being: nextTick fires as current operation ends, next event loop begins, normal event loop phases execute, setImmediate fires and recursively calls our step function to start the process all over again. Current operation ends, nextTick fires, etc.

The output of the above code would be:

nextTick iteration: 0
setImmediate iteration: 0
nextTick iteration: 1
setImmediate iteration: 1
nextTick iteration: 2
setImmediate iteration: 2
nextTick iteration: 3
setImmediate iteration: 3
nextTick iteration: 4
setImmediate iteration: 4
nextTick iteration: 5
setImmediate iteration: 5
nextTick iteration: 6
setImmediate iteration: 6
nextTick iteration: 7
setImmediate iteration: 7
nextTick iteration: 8
setImmediate iteration: 8
nextTick iteration: 9
setImmediate iteration: 9

Now let's move our recursive call to step into our nextTick handler instead of the setImmediate.

function step(iteration) {
  if (iteration === 10) return;
  setImmediate(() => {
    console.log(`setImmediate iteration: ${iteration}`);
  });
  process.nextTick(() => {
    console.log(`nextTick iteration: ${iteration}`);
    step(iteration + 1); // Recursive call from nextTick handler.
  });
}
step(0);

Now that we have moved the recursive call to step into the nextTick handler things will behave in a different order. Our first iteration of the event loop runs and calls step registering a setImmedaite handler as well as a nextTick handler. After the current operation ends our nextTick handler fires which recursively calls step and registers another setImmediate handler as well as another nextTick handler. Since a nextTick handler fires after the current operation, registering a nextTick handler within a nextTick handler will cause the second handler to run immediately after the current handler operation finishes. The nextTick handlers will keep firing, preventing the current event loop from ever continuing. We will get through all our nextTick handlers before we see a single setImmediate handler fire.

The output of the above code ends up being:

nextTick iteration: 0
nextTick iteration: 1
nextTick iteration: 2
nextTick iteration: 3
nextTick iteration: 4
nextTick iteration: 5
nextTick iteration: 6
nextTick iteration: 7
nextTick iteration: 8
nextTick iteration: 9
setImmediate iteration: 0
setImmediate iteration: 1
setImmediate iteration: 2
setImmediate iteration: 3
setImmediate iteration: 4
setImmediate iteration: 5
setImmediate iteration: 6
setImmediate iteration: 7
setImmediate iteration: 8
setImmediate iteration: 9

Note that had we not interrupted the recursive call and aborted it after 10 iterations then the nextTick calls would keep recursing and never letting the event loop continue to the next phase. This is how nextTick can become blocking when used recursively whereas setImmediate will fire in the next event loop and setting another setImmediate handler from within one won't interrupt the current event loop at all, allowing it to continue executing phases of the event loop as normal.

Hope that helps!

PS - I agree with other commenters that the names of the two functions could easily be swapped since nextTick sounds like it's going to fire in the next event loop rather than the end of the current one, and the end of the current loop is more "immediate" than the beginning of the next loop. Oh well, that's what we get as an API matures and people come to depend on existing interfaces.

Add custom buttons on Slick Carousel

I know this is an old question, but maybe I can be of help to someone, bc this also stumped me until I read the documentation a bit more:

prevArrow string (html|jQuery selector) | object (DOM node|jQuery object) Previous Allows you to select a node or customize the HTML for the "Previous" arrow.

nextArrow string (html|jQuery selector) | object (DOM node|jQuery object) Next Allows you to select a node or customize the HTML for the "Next" arrow.

this is how i changed my buttons.. worked perfectly.

  $('.carousel-content').slick({
      prevArrow:"<img class='a-left control-c prev slick-prev' src='../images/shoe_story/arrow-left.png'>",
      nextArrow:"<img class='a-right control-c next slick-next' src='../images/shoe_story/arrow-right.png'>"
  });

Setting default values to null fields when mapping with Jackson

Looks like the solution is to set the value of the properties inside the default constructor. So in this case the java class is:

class JavaObject {

    public JavaObject() {

        optionalMember = "Value";
    }

    @NotNull
    public String notNullMember;

    public String optionalMember;
}

After the mapping with Jackson, if the optionalMember is missing from the JSON its value in the Java class is "Value".

However, I am still interested to know if there is a solution with annotations and without the default constructor.

How to run Linux commands in Java?

try to use unix4j. it s about a library in java to run linux command. for instance if you got a command like: cat test.txt | grep "Tuesday" | sed "s/kilogram/kg/g" | sort in this program will become: Unix4j.cat("test.txt").grep("Tuesday").sed("s/kilogram/kg/g").sort();

Is there any use for unique_ptr with array?

If you need a dynamic array of objects that are not copy-constructible, then a smart pointer to an array is the way to go. For example, what if you need an array of atomics.

Setting the selected value on a Django forms.ChoiceField

You can also do the following. in your form class def:

max_number = forms.ChoiceField(widget = forms.Select(), 
                 choices = ([('1','1'), ('2','2'),('3','3'), ]), initial='3', required = True,)

then when calling the form in your view you can dynamically set both initial choices and choice list.

yourFormInstance = YourFormClass()

yourFormInstance.fields['max_number'].choices = [(1,1),(2,2),(3,3)]
yourFormInstance.fields['max_number'].initial = [1]

Note: the initial values has to be a list and the choices has to be 2-tuples, in my example above i have a list of 2-tuples. Hope this helps.

Need a good hex editor for Linux

I am a VIMer. I can do some rare Hex edits with:

  • :%!xxd to switch into hex mode

  • :%!xxd -r to exit from hex mode

But I strongly recommend ht

apt-cache show ht

Package: ht
Version: 2.0.18-1
Installed-Size: 1780
Maintainer: Alexander Reichle-Schmehl <[email protected]>

Homepage: http://hte.sourceforge.net/

Note: The package is called ht, whereas the executable is named hte after the package was installed.

  1. Supported file formats
    • common object file format (COFF/XCOFF32)
    • executable and linkable format (ELF)
    • linear executables (LE)
    • standard DO$ executables (MZ)
    • new executables (NE)
    • portable executables (PE32/PE64)
    • java class files (CLASS)
    • Mach exe/link format (MachO)
    • X-Box executable (XBE)
    • Flat (FLT)
    • PowerPC executable format (PEF)
  2. Code & Data Analyser
    • finds branch sources and destinations recursively
    • finds procedure entries
    • creates labels based on this information
    • creates xref information
    • allows to interactively analyse unexplored code
    • allows to create/rename/delete labels
    • allows to create/edit comments
    • supports x86, ia64, alpha, ppc and java code
  3. Target systems
    • DJGPP
    • GNU/Linux
    • FreeBSD
    • OpenBSD
    • Win32

How do I make a JAR from a .java file?

Simply with command line:

javac MyApp.java
jar -cf myJar.jar MyApp.class

Sure IDEs avoid using command line terminal

Exception : javax.net.ssl.SSLPeerUnverifiedException: peer not authenticated

if you are in dev mode with not valid certificate, why not just set weClient.setUseInsecureSSL(true). works for me

Escape dot in a regex range

On this web page, I see that:

"Remember that the dot is not a metacharacter inside a character class, so we do not need to escape it with a backslash."

So I guess the escaping of it is unnecessary...

Getting min and max Dates from a pandas dataframe

'Date' is your index so you want to do,

print (df.index.min())
print (df.index.max())

2014-03-13 00:00:00
2014-03-31 00:00:00

How to get row count in sqlite using Android?

In order to query a table for the number of rows in that table, you want your query to be as efficient as possible. Reference.

Use something like this:

/**
 * Query the Number of Entries in a Sqlite Table
 * */
public long QueryNumEntries()
{
    SQLiteDatabase db = this.getReadableDatabase();
    return DatabaseUtils.queryNumEntries(db, "table_name");
}

Assign variable value inside if-statement

Because I know it's possible in while conditions, but I'm not sure if I'm doing it wrong for the if-statement or if it's just not possible.

HINT: what type while and if condition should be ??

If it can be done with while, it can be done with if statement as weel, as both of them expect a boolean condition.

How do I force my .NET application to run as administrator?

THIS DOES NOT FORCE APPLICATION TO WORK AS ADMINISTRATOR.
This is a simplified version of the this answer, above by @NG

public bool IsUserAdministrator()
{
    try
    {
        WindowsIdentity user = WindowsIdentity.GetCurrent();
        WindowsPrincipal principal = new WindowsPrincipal(user);
        return principal.IsInRole(WindowsBuiltInRole.Administrator);
    }
    catch
    {
        return false;
    }
}

Visual Studio Community 2015 expiration date

In case you had enabled 2-Step verification for your Microsoft account disable it when updating the VS License using the 'Check for Updated License' option provided in the window.

Compilation error - missing zlib.h

You have installed the library in a non-standard location ($HOME/zlib/). That means the compiler will not know where your header files are and you need to tell the compiler that.

You can add a path to the list that the compiler uses to search for header files by using the -I (upper-case i) option.

Also note that the LD_LIBRARY_PATH is for the run-time linker and loader, and is searched for dynamic libraries when attempting to run an application. To add a path for the build-time linker use the -L option.

All-together the command line should look like

$ c++ -I$HOME/zlib/include some_file.cpp -L$HOME/zlib/lib -lz

Hide text within HTML?

you can use css property to hide style="display:none;"

<div style="display:none;">CREDITS_HERE</div>

what does Error "Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)" mean?

Your secondNumber seems to be an ivar, so you have to use a local var to unwrap the optional. And careful. You don't test secondNumber for 0, which can lead into a division by zero. Technically you need another case to handle an impossible operation. For instance checkin if the number is 0 and do nothing in that case would at least not crash.

@IBAction func equals(sender: AnyObject) {

    guard let number = Screen.text?.toInt(), number > 0 else {
        return
    }

    secondNumber = number

    if operation == "+"{
        result = firstNumber + secondNumber
    }
    else if operation == "-" {
        result = firstNumber - secondNumber
    }
    else if operation == "x" {
        result = firstNumber * secondNumber
    }
    else {
        result = firstNumber / secondNumber
    }
    Screen.text = "\(result)"
}

How should I use Outlook to send code snippets?

When I paste code into Outlook or have sentences containing code or technical syntax I get annoyed by all of the red squiggles that identify spelling errors. If you want Outlook to clear all of the red spellcheck squiggles you can add a button to the Quick Access Toolbar that calls a VBA macro and removes all squiggles from the current document.

I prefer to run this macro separate from my style choice because I often use it on a selection of text that has mixed content.

For syntax highlighting I use the Notepad++ technique already listed by @srujanreddy, though I discovered that the right-click context menu option a bit handier than navigating the Plugins menu.

Image showing you can right-click on selected text and choose to copy text with syntax highlighting

If you get annoyed by spell check while you are preparing your email you can add a button to your quick access toolbar that will remove the red squiggles from the message body.
See this article: https://stackoverflow.com/a/49865743/1898524

Remove Spell Check Squiggles

Get the current year in JavaScript

// Return today's date and time
var currentTime = new Date()

// returns the month (from 0 to 11)
var month = currentTime.getMonth() + 1

// returns the day of the month (from 1 to 31)
var day = currentTime.getDate()

// returns the year (four digits)
var year = currentTime.getFullYear()

// write output MM/dd/yyyy
document.write(month + "/" + day + "/" + year)

How to POST raw whole JSON in the body of a Retrofit request?

use following to send json

final JSONObject jsonBody = new JSONObject();
    try {

        jsonBody.put("key", "value");

    } catch (JSONException e){
        e.printStackTrace();
    }
    RequestBody body = RequestBody.create(okhttp3.MediaType.parse("application/json; charset=utf-8"),(jsonBody).toString());

and pass it to url

@Body RequestBody key

MySQL case sensitive query

Whilst the listed answer is correct, may I suggest that if your column is to hold case sensitive strings you read the documentation and alter your table definition accordingly.

In my case this amounted to defining my column as:

`tag` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT ''

This is in my opinion preferential to adjusting your queries.

What is stdClass in PHP?

is a way in which the avoid stopping interpreting the script when there is some data must be put in a class , but unfortunately this class was not defined

Example :

 return $statement->fetchAll(PDO::FETCH_CLASS  , 'Tasks');

Here the data will be put in the predefined 'Tasks' . But, if we did the code as this :

 return $statement->fetchAll(PDO::FETCH_CLASS );

then the will put the results in .

simply says that : look , we have a good KIDS[Objects] Here but without Parents . So , we will send them to a infant child Care Home :)

How do I monitor all incoming http requests?

You can also try the HTTP Debugger, it has the built-in ability to display incoming HTTP requests and does not require any changes to the system configuration.

HTTP Debugger

How do I write a Windows batch script to copy the newest file from a directory?

This will open a second cmd.exe window. If you want it to go away, replace the /K with /C.

Obviously, replace new_file_loc with whatever your new file location will be.

@echo off
for /F %%i in ('dir /B /O:-D *.txt') do (
    call :open "%%i"
    exit /B 0
)
:open
    start "window title" "cmd /K copy %~1 new_file_loc"
exit /B 0

Java: Finding the highest value in an array

Easiest way which I've found, supports all android versions

Arrays.sort(series1Numbers);

int maxSeries = Integer.parseInt(String.valueOf(series1Numbers[series1Numbers.length-1]));

Get value of Span Text

<script type="text/javascript">
document.getElementById('button1').onChange = function () {
    document.getElementById('hidden_field_id').value = document.getElementById('span_id').innerHTML;
}
</script>

key_load_public: invalid format

So, after update I had the same issue. I was using PEM key_file without extension and simply adding .pem fixed my issue. Now the file is key_file.pem.

How to synchronize a static variable among threads running different instances of a class in Java?

We can also use ReentrantLock to achieve the synchronization for static variables.

public class Test {

    private static int count = 0;
    private static final ReentrantLock reentrantLock = new ReentrantLock(); 
    public void foo() {  
        reentrantLock.lock();
        count = count + 1;
        reentrantLock.unlock();
    }  
}

Check if any ancestor has a class using jQuery

if ($elem.parents('.left').length) {

}

Prevent WebView from displaying "web page not available"

The best solution I have found is to load an empty page in the OnReceivedError event like this:

@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
    super.onReceivedError(view, errorCode, description, failingUrl);

    view.loadUrl("about:blank");
}

Default visibility for C# classes and members (fields, methods, etc.)?

From MSDN:

Top-level types, which are not nested in other types, can only have internal or public accessibility. The default accessibility for these types is internal.


Nested types, which are members of other types, can have declared accessibilities as indicated in the following table.

Default Nested Member Accessibility & Allowed Accessibility Modifiers

Source: Accessibility Levels (C# Reference) (December 6th, 2017)

Setting Icon for wpf application (VS 08)

Assuming you use VS Express and C#. The icon is set in the project properties page. To open it right click on the project name in the solution explorer. in the page that opens, there is an Application tab, in this tab you can set the icon.

No tests found for given includes Error, when running Parameterized Unit test in Android Studio

To add to already great and easy solution provided by Przemek315, the same config if you use Kotlin DSL:

tasks.test {
    useJUnitPlatform()
}

javascript jquery radio button click

There are several ways to do this. Having a container around the radio buttons is highly recommended regardless, but you can also put a class directly on the buttons. With this HTML:

<ul id="shapeList" class="radioList">
<li><label>Shape:</label></li>
<li><input id="shapeList_0" class="shapeButton" type="radio" value="Circular" name="shapeList" /><label for="shapeList_0">Circular</label></li>
<li><input id="shapeList_1" class="shapeButton" type="radio" value="Rectangular" name="shapeList" /><label for="shapeList_1">Rectangular</label></li>
</ul>

you can select by class:

$(".shapeButton").click(SetShape);

or select by container ID:

$("#shapeList").click(SetShape);

In either case, the event will trigger on clicking either the radio button or the label for it, though oddly in the latter case (Selecting by "#shapeList"), clicking on the label will trigger the click function twice for some reason, at least in FireFox; selecting by class won't do that.

SetShape is a function, and looks like this:

function SetShape() {
    var Shape = $('.shapeButton:checked').val();
//dostuff
}

This way, you can have labels on your buttons, and can have multiple radio button lists on the same page that do different things. You can even have each individual button in the same list do different things by setting up different behavior in SetShape() based on the button's value.

What is the equivalent of Java's final in C#?

The final keyword has several usages in Java. It corresponds to both the sealed and readonly keywords in C#, depending on the context in which it is used.

Classes

To prevent subclassing (inheritance from the defined class):

Java

public final class MyFinalClass {...}

C#

public sealed class MyFinalClass {...}

Methods

Prevent overriding of a virtual method.

Java

public class MyClass
{
    public final void myFinalMethod() {...}
}

C#

public class MyClass : MyBaseClass
{
    public sealed override void MyFinalMethod() {...}
}

As Joachim Sauer points out, a notable difference between the two languages here is that Java by default marks all non-static methods as virtual, whereas C# marks them as sealed. Hence, you only need to use the sealed keyword in C# if you want to stop further overriding of a method that has been explicitly marked virtual in the base class.

Variables

To only allow a variable to be assigned once:

Java

public final double pi = 3.14; // essentially a constant

C#

public readonly double pi = 3.14; // essentially a constant

As a side note, the effect of the readonly keyword differs from that of the const keyword in that the readonly expression is evaluated at runtime rather than compile-time, hence allowing arbitrary expressions.

Node.js ES6 classes with require

In class file you can either use:

module.exports = class ClassNameHere {
 print() {
  console.log('In print function');
 }
}

or you can use this syntax

class ClassNameHere{
 print(){
  console.log('In print function');
 }
}

module.exports = ClassNameHere;

On the other hand to use this class in any other file you need to do these steps. First require that file using this syntax: const anyVariableNameHere = require('filePathHere');

Then create an object const classObject = new anyVariableNameHere();

After this you can use classObject to access the actual class variables

Python - Dimension of Data Frame

Summary of all ways to get info on dimensions of DataFrame or Series

There are a number of ways to get information on the attributes of your DataFrame or Series.

Create Sample DataFrame and Series

df = pd.DataFrame({'a':[5, 2, np.nan], 'b':[ 9, 2, 4]})
df

     a  b
0  5.0  9
1  2.0  2
2  NaN  4

s = df['a']
s

0    5.0
1    2.0
2    NaN
Name: a, dtype: float64

shape Attribute

The shape attribute returns a two-item tuple of the number of rows and the number of columns in the DataFrame. For a Series, it returns a one-item tuple.

df.shape
(3, 2)

s.shape
(3,)

len function

To get the number of rows of a DataFrame or get the length of a Series, use the len function. An integer will be returned.

len(df)
3

len(s)
3

size attribute

To get the total number of elements in the DataFrame or Series, use the size attribute. For DataFrames, this is the product of the number of rows and the number of columns. For a Series, this will be equivalent to the len function:

df.size
6

s.size
3

ndim attribute

The ndim attribute returns the number of dimensions of your DataFrame or Series. It will always be 2 for DataFrames and 1 for Series:

df.ndim
2

s.ndim
1

The tricky count method

The count method can be used to return the number of non-missing values for each column/row of the DataFrame. This can be very confusing, because most people normally think of count as just the length of each row, which it is not. When called on a DataFrame, a Series is returned with the column names in the index and the number of non-missing values as the values.

df.count() # by default, get the count of each column

a    2
b    3
dtype: int64


df.count(axis='columns') # change direction to get count of each row

0    2
1    2
2    1
dtype: int64

For a Series, there is only one axis for computation and so it just returns a scalar:

s.count()
2

Use the info method for retrieving metadata

The info method returns the number of non-missing values and data types of each column

df.info()

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 3 entries, 0 to 2
Data columns (total 2 columns):
a    2 non-null float64
b    3 non-null int64
dtypes: float64(1), int64(1)
memory usage: 128.0 bytes

Find where java class is loaded from

Take a look at this similar question. Tool to discover same class..

I think the most relevant obstacle is if you have a custom classloader ( loading from a db or ldap )

How can javascript upload a blob?

I tried all the solutions above and in addition, those in related answers as well. Solutions including but not limited to passing the blob manually to a HTMLInputElement's file property, calling all the readAs* methods on FileReader, using a File instance as second argument for a FormData.append call, trying to get the blob data as a string by getting the values at URL.createObjectURL(myBlob) which turned out nasty and crashed my machine.

Now, if you happen to attempt those or more and still find you're unable to upload your blob, it could mean the problem is server-side. In my case, my blob exceeded the http://www.php.net/manual/en/ini.core.php#ini.upload-max-filesize and post_max_size limit in PHP.INI so the file was leaving the front end form but getting rejected by the server. You could either increase this value directly in PHP.INI or via .htaccess

Using partial views in ASP.net MVC 4

Change the code where you load the partial view to:

@Html.Partial("_CreateNote", new QuickNotes.Models.Note())

This is because the partial view is expecting a Note but is getting passed the model of the parent view which is the IEnumerable

failed to find target with hash string android-23

Update: Does not apply to the Android Studio released after this answer (April 2016)

Note: I think this might be a bug in Android Studio.

enter image description here

  1. Go to Project Structure
  2. Select App Module
  3. Under the first tab "Properties" change the Compile SDK Version to API XX from Google API xx (e.g. API 23 instead of Google API 23)
  4. Press OK
  5. Wait for the completion of on going process, in my case I did not get an error at this point.

Now revert Compiled Sdk Version back to Google API xx.

If this not work, then:

  1. With Google API (Google API xx instead of API xx), lower the build tool version (e.g. Google API 23 and build tool version 23.0.1)
  2. Press Ok and wait for completion of on going process
  3. Revert back your build tool version to what it was before you changed
  4. Press Ok
  5. Wait for the completion of process.
  6. Done!

How can get the text of a div tag using only javascript (no jQuery)

You'll probably want to try textContent instead of innerHTML.

Given innerHTML will return DOM content as a String and not exclusively the "text" in the div. It's fine if you know that your div contains only text but not suitable if every use case. For those cases, you'll probably have to use textContent instead of innerHTML

For example, considering the following markup:

<div id="test">
  Some <span class="foo">sample</span> text.
</div>

You'll get the following result:

var node = document.getElementById('test'),

htmlContent = node.innerHTML,
// htmlContent = "Some <span class="foo">sample</span> text."

textContent = node.textContent;
// textContent = "Some sample text."

See MDN for more details:

How to format a UTC date as a `YYYY-MM-DD hh:mm:ss` string using NodeJS?

Easily readable and customisable way to get a timestamp in your desired format, without use of any library:

function timestamp(){
  function pad(n) {return n<10 ? "0"+n : n}
  d=new Date()
  dash="-"
  colon=":"
  return d.getFullYear()+dash+
  pad(d.getMonth()+1)+dash+
  pad(d.getDate())+" "+
  pad(d.getHours())+colon+
  pad(d.getMinutes())+colon+
  pad(d.getSeconds())
}

(If you require time in UTC format, then just change the function calls. For example "getMonth" becomes "getUTCMonth")

Tomcat startup logs - SEVERE: Error filterStart how to get a stack trace?

Run Following command to show catalina logs on the terminal---

sh start-camunda.sh; tail -f server/apache-tomcat-8.0.24/logs/catalina.out

How to navigate to a directory in C:\ with Cygwin?

I'll add something that helps me out a lot with cygwin. Whenever setting up a new system, I always do this

ln -s /cygdrive/c /c

This creates a symbolic link to /cygdrive/c with a new file called /c (in the home directory)

Then you can do this in your shell

cd /c/Foo
cd /c/

Very handy.

Counting number of lines, words, and characters in a text file

I think the best answer is

int words = 0;
int lines = 0;
int chars = 0;
while(in.hasNextLine())  {
    lines++;
    String line = in.nextLine();
   for(int i=0;i<line.length();i++)
    {
        if(line.charAt(i)!=' ' && line.charAt(i)!='\n')
        chars ++;
    }
    words += new StringTokenizer(line, " ,").countTokens();
}

Arrays in cookies PHP

To store the array values in cookie, first you need to convert them to string, so here is some options.

Storing cookies as JSON

Storing code

setcookie('your_cookie_name', json_encode($info), time()+3600);

Reading code

$data = json_decode($_COOKIE['your_cookie_name'], true);

JSON can be good choose also if you need read cookie in front end with JavaScript.

Actually you can use any encrypt_array_to_string/decrypt_array_from_string methods group that will convert array to string and convert string back to same array. For example you can also use explode/implode for array of integers.

Warning: Do not use serialize/unserialize

From PHP.net

enter image description here

Do not pass untrusted user input to unserialize(). - Anything that coming by HTTP including cookies is untrusted!

References related to security

As an alternative solution, you can do it also without converting array to string.

setcookie('my_array[0]', 'value1' , time()+3600);
setcookie('my_array[1]', 'value2' , time()+3600);
setcookie('my_array[2]', 'value3' , time()+3600);

And after if you will print $_COOKIE variable, you will see the following

echo '<pre>';
print_r( $_COOKIE );
die();
Array
(   
    [my_array] => Array
        (
            [0] => value1
            [1] => value2
            [2] => value3
        )

)

This is documented PHP feature.

From PHP.net

Cookies names can be set as array names and will be available to your PHP scripts as arrays but separate cookies are stored on the user's system.

How is a JavaScript hash map implemented?

Here is an easy and convenient way of using something similar to the Java map:

var map= {
    'map_name_1': map_value_1,
    'map_name_2': map_value_2,
    'map_name_3': map_value_3,
    'map_name_4': map_value_4
    }

And to get the value:

alert( map['map_name_1'] );    // fives the value of map_value_1

......  etc  .....

Is it possible to have a multi-line comments in R?

You can, if you want, use standalone strings for multi-line comments — I've always thought that prettier than if (FALSE) { } blocks. The string will get evaluated and then discarded, so as long as it's not the last line in a function nothing will happen.

"This function takes a value x, and does things and returns things that
 take several lines to explain"
doEverythingOften <- function(x) {
     # Non! Comment it out! We'll just do it once for now.
     "if (x %in% 1:9) {
          doTenEverythings()
     }"
     doEverythingOnce()
     ...
     return(list(
         everythingDone = TRUE, 
         howOftenDone = 1
     ))
}

The main limitation is that when you're commenting stuff out, you've got to watch your quotation marks: if you've got one kind inside, you'll have to use the other kind for the comment; and if you've got something like "strings with 'postrophes" inside that block, then there's no way this method is a good idea. But then there's still the if (FALSE) block.

The other limitation, one that both methods have, is that you can only use such blocks in places where an expression would be syntactically valid - no commenting out parts of lists, say.

Regarding what do in which IDE: I'm a Vim user, and I find NERD Commenter an utterly excellent tool for quickly commenting or uncommenting multiple lines. Very user-friendly, very well-documented.

Lastly, at the R prompt (at least under Linux), there's the lovely Alt-Shift-# to comment the current line. Very nice to put a line 'on hold', if you're working on a one-liner and then realise you need a prep step first.

how to show only even or odd rows in sql server 2008?

  SELECT * FROM (SELECT ROW_NUMBER () OVER (ORDER BY sal DESC) row_number, sr,sal FROM empsal) a WHERE (row_number%2) = 1

and

      SELECT * FROM (SELECT ROW_NUMBER () OVER (ORDER BY sal DESC) row_number, sr,sal FROM   empsal) a WHERE (row_number%2) = 0

Instantly detect client disconnection from server socket

Expanding on comments by mbargiel and mycelo on the accepted answer, the following can be used with a non-blocking socket on the server end to inform whether the client has shut down.

This approach does not suffer the race condition that affects the Poll method in the accepted answer.

// Determines whether the remote end has called Shutdown
public bool HasRemoteEndShutDown
{
    get
    {
        try
        {
            int bytesRead = socket.Receive(new byte[1], SocketFlags.Peek);

            if (bytesRead == 0)
                return true;
        }
        catch
        {
            // For a non-blocking socket, a SocketException with 
            // code 10035 (WSAEWOULDBLOCK) indicates no data available.
        }

        return false;
    }
}

The approach is based on the fact that the Socket.Receive method returns zero immediately after the remote end shuts down its socket and we've read all of the data from it. From Socket.Receive documentation:

If the remote host shuts down the Socket connection with the Shutdown method, and all available data has been received, the Receive method will complete immediately and return zero bytes.

If you are in non-blocking mode, and there is no data available in the protocol stack buffer, the Receive method will complete immediately and throw a SocketException.

The second point explains the need for the try-catch.

Use of the SocketFlags.Peek flag leaves any received data untouched for a separate receive mechanism to read.

The above will work with a blocking socket as well, but be aware that the code will block on the Receive call (until data is received or the receive timeout elapses, again resulting in a SocketException).

Better way to shuffle two numpy arrays in unison

Your "scary" solution does not appear scary to me. Calling shuffle() for two sequences of the same length results in the same number of calls to the random number generator, and these are the only "random" elements in the shuffle algorithm. By resetting the state, you ensure that the calls to the random number generator will give the same results in the second call to shuffle(), so the whole algorithm will generate the same permutation.

If you don't like this, a different solution would be to store your data in one array instead of two right from the beginning, and create two views into this single array simulating the two arrays you have now. You can use the single array for shuffling and the views for all other purposes.

Example: Let's assume the arrays a and b look like this:

a = numpy.array([[[  0.,   1.,   2.],
                  [  3.,   4.,   5.]],

                 [[  6.,   7.,   8.],
                  [  9.,  10.,  11.]],

                 [[ 12.,  13.,  14.],
                  [ 15.,  16.,  17.]]])

b = numpy.array([[ 0.,  1.],
                 [ 2.,  3.],
                 [ 4.,  5.]])

We can now construct a single array containing all the data:

c = numpy.c_[a.reshape(len(a), -1), b.reshape(len(b), -1)]
# array([[  0.,   1.,   2.,   3.,   4.,   5.,   0.,   1.],
#        [  6.,   7.,   8.,   9.,  10.,  11.,   2.,   3.],
#        [ 12.,  13.,  14.,  15.,  16.,  17.,   4.,   5.]])

Now we create views simulating the original a and b:

a2 = c[:, :a.size//len(a)].reshape(a.shape)
b2 = c[:, a.size//len(a):].reshape(b.shape)

The data of a2 and b2 is shared with c. To shuffle both arrays simultaneously, use numpy.random.shuffle(c).

In production code, you would of course try to avoid creating the original a and b at all and right away create c, a2 and b2.

This solution could be adapted to the case that a and b have different dtypes.

Add a column to a table, if it does not already exist

IF NOT EXISTS (SELECT * FROM syscolumns
  WHERE ID=OBJECT_ID('[db].[Employee]') AND NAME='EmpName')
  ALTER TABLE [db].[Employee]
  ADD [EmpName] VARCHAR(10)
GO

I Hope this would help. More info

java doesn't run if structure inside of onclick listener

both your conditions are the same:

if(s < f) {     calc = f - s;     n = s; }else if(f > s){     calc =  s - f;     n = f;  } 

so

if(s < f)   

and

}else if(f > s){ 

are the same

change to

}else if(f < s){ 

How do I use su to execute the rest of the bash script as that user?

The trick is to use "sudo" command instead of "su"

You may need to add this

username1 ALL=(username2) NOPASSWD: /path/to/svn

to your /etc/sudoers file

and change your script to:

sudo -u username2 -H sh -c "cd /home/$USERNAME/$PROJECT; svn update" 

Where username2 is the user you want to run the SVN command as and username1 is the user running the script.

If you need multiple users to run this script, use a %groupname instead of the username1

How to import data from text file to mysql database

You should set the option:

local-infile=1

into your [mysql] entry of my.cnf file or call mysql client with the --local-infile option:

mysql --local-infile -uroot -pyourpwd yourdbname

You have to be sure that the same parameter is defined into your [mysqld] section too to enable the "local infile" feature server side.

It's a security restriction.

LOAD DATA LOCAL INFILE '/softwares/data/data.csv' INTO TABLE tableName;

Best practice for localization and globalization of strings and labels

When you’re faced with a problem to solve (and frankly, who isn’t these days?), the basic strategy usually taken by we computer people is called “divide and conquer.” It goes like this:

  • Conceptualize the specific problem as a set of smaller sub-problems.
  • Solve each smaller problem.
  • Combine the results into a solution of the specific problem.

But “divide and conquer” is not the only possible strategy. We can also take a more generalist approach:

  • Conceptualize the specific problem as a special case of a more general problem.
  • Somehow solve the general problem.
  • Adapt the solution of the general problem to the specific problem.

- Eric Lippert

I believe many solutions already exist for this problem in server-side languages such as ASP.Net/C#.

I've outlined some of the major aspects of the problem

  • Issue: We need to load data only for the desired language

    Solution: For this purpose we save data to a separate files for each language

ex. res.de.js, res.fr.js, res.en.js, res.js(for default language)

  • Issue: Resource files for each page should be separated so we only get the data we need

    Solution: We can use some tools that already exist like https://github.com/rgrove/lazyload

  • Issue: We need a key/value pair structure to save our data

    Solution: I suggest a javascript object instead of string/string air. We can benefit from the intellisense from an IDE

  • Issue: General members should be stored in a public file and all pages should access them

    Solution: For this purpose I make a folder in the root of web application called Global_Resources and a folder to store global file for each sub folders we named it 'Local_Resources'

  • Issue: Each subsystems/subfolders/modules member should override the Global_Resources members on their scope

    Solution: I considered a file for each

Application Structure

root/
    Global_Resources/
        default.js
        default.fr.js
    UserManagementSystem/
        Local_Resources/
            default.js
            default.fr.js
            createUser.js
        Login.htm
        CreateUser.htm

The corresponding code for the files:

Global_Resources/default.js

var res = {
    Create : "Create",
    Update : "Save Changes",
    Delete : "Delete"
};

Global_Resources/default.fr.js

var res = {
    Create : "créer",
    Update : "Enregistrer les modifications",
    Delete : "effacer"
};

The resource file for the desired language should be loaded on the page selected from Global_Resource - This should be the first file that is loaded on all the pages.

UserManagementSystem/Local_Resources/default.js

res.Name = "Name";
res.UserName = "UserName";
res.Password = "Password";

UserManagementSystem/Local_Resources/default.fr.js

res.Name = "nom";
res.UserName = "Nom d'utilisateur";
res.Password = "Mot de passe";

UserManagementSystem/Local_Resources/createUser.js

// Override res.Create on Global_Resources/default.js
res.Create = "Create User"; 

UserManagementSystem/Local_Resources/createUser.fr.js

// Override Global_Resources/default.fr.js
res.Create = "Créer un utilisateur";

manager.js file (this file should be load last)

res.lang = "fr";

var globalResourcePath = "Global_Resources";
var resourceFiles = [];

var currentFile = globalResourcePath + "\\default" + res.lang + ".js" ;

if(!IsFileExist(currentFile))
    currentFile = globalResourcePath + "\\default.js" ;
if(!IsFileExist(currentFile)) throw new Exception("File Not Found");

resourceFiles.push(currentFile);

// Push parent folder on folder into folder
foreach(var folder in parent folder of current page)
{
    currentFile = folder + "\\Local_Resource\\default." + res.lang + ".js";

    if(!IsExist(currentFile))
        currentFile = folder + "\\Local_Resource\\default.js";
    if(!IsExist(currentFile)) throw new Exception("File Not Found");

    resourceFiles.push(currentFile);
}

for(int i = 0; i < resourceFiles.length; i++) { Load.js(resourceFiles[i]); }

// Get current page name
var pageNameWithoutExtension = "SomePage";

currentFile = currentPageFolderPath + pageNameWithoutExtension + res.lang + ".js" ;

if(!IsExist(currentFile))
    currentFile = currentPageFolderPath + pageNameWithoutExtension + ".js" ;
if(!IsExist(currentFile)) throw new Exception("File Not Found");

Hope it helps :)

How to remove padding around buttons in Android?

You can use Borderless style in AppCompatButton like below. and use android:background with it.

style="@style/Widget.AppCompat.Button.Borderless.Colored"

Button code

<androidx.appcompat.widget.AppCompatButton
        android:id="@+id/button_visa_next"
        android:background="@color/colorPrimary"
        style="@style/Widget.AppCompat.Button.Borderless.Colored"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/spacing_normal"
        android:text="@string/next"
        android:textColor="@color/white"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

Output:

enter image description here

Sending images using Http Post

Version 4.3.5 Updated Code

  • httpclient-4.3.5.jar
  • httpcore-4.3.2.jar
  • httpmime-4.3.5.jar

Since MultipartEntity has been deprecated. Please see the code below.

String responseBody = "failure";
HttpClient client = new DefaultHttpClient();
client.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1);

String url = WWPApi.URL_USERS;
Map<String, String> map = new HashMap<String, String>();
map.put("user_id", String.valueOf(userId));
map.put("action", "update");
url = addQueryParams(map, url);

HttpPost post = new HttpPost(url);
post.addHeader("Accept", "application/json");

MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.setCharset(MIME.UTF8_CHARSET);

if (career != null)
    builder.addTextBody("career", career, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (gender != null)
    builder.addTextBody("gender", gender, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (username != null)
    builder.addTextBody("username", username, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (email != null)
    builder.addTextBody("email", email, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (password != null)
    builder.addTextBody("password", password, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (country != null)
    builder.addTextBody("country", country, ContentType.create("text/plain", MIME.UTF8_CHARSET));
if (file != null)
    builder.addBinaryBody("Filedata", file, ContentType.MULTIPART_FORM_DATA, file.getName());

post.setEntity(builder.build());

try {
    responseBody = EntityUtils.toString(client.execute(post).getEntity(), "UTF-8");
//  System.out.println("Response from Server ==> " + responseBody);

    JSONObject object = new JSONObject(responseBody);
    Boolean success = object.optBoolean("success");
    String message = object.optString("error");

    if (!success) {
        responseBody = message;
    } else {
        responseBody = "success";
    }

} catch (Exception e) {
    e.printStackTrace();
} finally {
    client.getConnectionManager().shutdown();
}

Tests not running in Test Explorer

What works for me is to delete the bin folder, then rebuild the project.

How to navigate a few folders up?

This is what worked best for me:

string parentOfStartupPath = Path.GetFullPath(Path.Combine(Application.StartupPath, @"../"));

Getting the 'right' path wasn't the problem, adding '../' obviously does that, but after that, the given string isn't usable, because it will just add the '../' at the end. Surrounding it with Path.GetFullPath() will give you the absolute path, making it usable.

How to set the id attribute of a HTML element dynamically with angularjs (1.x)?

In case you came to this question but related to newer Angular version >= 2.0.

<div [id]="element.id"></div>

iOS - Dismiss keyboard when touching outside of UITextField

Swift version of @Jensen2k's answer:

let gestureRecognizer : UITapGestureRecognizer = UITapGestureRecognizer.init(target: self, action: "dismissKeyboard")
self.view.addGestureRecognizer(gestureRecognizer)

func dismissKeyboard() {
    aTextField.resignFirstResponder()
}

One liner

self.view.addTapGesture(UITapGestureRecognizer.init(target: self, action: "endEditing:"))

Prevent form redirect OR refresh on submit?

Just handle the form submission on the submit event, and return false:

$('#contactForm').submit(function () {
 sendContactForm();
 return false;
});

You don't need any more the onclick event on the submit button:

<input class="submit" type="submit" value="Send" />

PHP string concatenation

One step (IMHO) better

$result .= $personCount . ' people';

How to convert string values from a dictionary, into int/float datatypes?

  newlist=[]                       #make an empty list
  for i in list:                   # loop to hv a dict in list  
     s={}                          # make an empty dict to store new dict data 
     for k in i.keys():            # to get keys in the dict of the list 
         s[k]=int(i[k])        # change the values from string to int by int func
     newlist.append(s)             # to add the new dict with integer to the list

scipy.misc module has no attribute imread?

imread is depreciated after version 1.2.0! So to solve this issue I had to install version 1.1.0.

pip install scipy==1.1.0

How to set an button align-right with Bootstrap?

function Continue({show, onContinue}) {
  return(<div className="row continue">
  { show ? <div className="col-11">
    <button class="btn btn-primary btn-lg float-right" onClick= {onContinue}>Continue</button>
    </div>
    : null }
  </div>);
}

How do I dynamically set HTML5 data- attributes using react?

Note - if you want to pass a data attribute to a React Component, you need to handle them a little differently than other props.

2 options

Don't use camel case

<Option data-img-src='value' ... />

And then in the component, because of the dashes, you need to refer to the prop in quotes.

// @flow
class Option extends React.Component {

  props: {
    'data-img-src': string
  }

And when you refer to it later, you don't use the dot syntax

  render () {
    return (
      <option data-img-src={this.props['data-img-src']} >...</option>
    )
  }
}

Or use camel case

<Option dataImgSrc='value' ... />

And then in the component, you need to convert.

// @flow
class Option extends React.Component {

  props: {
    dataImgSrc: string
  }

And when you refer to it later, you don't use the dot syntax

  render () {
    return (
      <option data-img-src={this.props.dataImgSrc} >...</option>
    )
  }
}

Mainly just realize data- attributes and aria- attributes are treated specially. You are allowed to use hyphens in the attribute name in those two cases.

FIFO class in Java

Try ArrayDeque or LinkedList, which both implement the Queue interface.

http://docs.oracle.com/javase/6/docs/api/java/util/ArrayDeque.html

Unicode character for "X" cancel / close?

&times; is better than &#10006; as &#10006; behaves strangely in Edge and Internet explorer (tested in IE11). It doesn't get the right color and is replaced by an "emoji"

Find the differences between 2 Excel worksheets?

COUNTIF works well for quick difference-checking. And it's easier to remember and simpler to work with than VLOOKUP.

=COUNTIF([Book1]Sheet1!$A:$A, A1) 

will give you a column showing 1 if there's match and zero if there's no match (with the bonus of showing >1 for duplicates within the list itself).

How can I execute Shell script in Jenkinsfile?

There's the Managed Script Plugin which provides an easy way of managing user scripts. It also adds a build step action which allows you to select which user script to execute.

When do I need to use Begin / End Blocks and the Go keyword in SQL Server?

After wrestling with this problem today my opinion is this: BEGIN...END brackets code just like {....} does in C languages, e.g. code blocks for if...else and loops

GO is (must be) used when succeeding statements rely on an object defined by a previous statement. USE database is a good example above, but the following will also bite you:

alter table foo add bar varchar(8);
-- if you don't put GO here then the following line will error as it doesn't know what bar is.
update foo set bar = 'bacon';
-- need a GO here to tell the interpreter to execute this statement, otherwise the Parser will lump it together with all successive statements.

It seems to me the problem is this: the SQL Server SQL Parser, unlike the Oracle one, is unable to realise that you're defining a new symbol on the first line and that it's ok to reference in the following lines. It doesn't "see" the symbol until it encounters a GO token which tells it to execute the preceding SQL since the last GO, at which point the symbol is applied to the database and becomes visible to the parser.

Why it doesn't just treat the semi-colon as a semantic break and apply statements individually I don't know and wish it would. Only bonus I can see is that you can put a print() statement just before the GO and if any of the statements fail the print won't execute. Lot of trouble for a minor gain though.

How to change font in ipython notebook

Using Jupyterthemes, one can easily change look of notebook.

pip install jupyterthemes

jt -fs 15 

By default code font size is set to 11 . Trying above will change font size. It can be reset using.

jt -r 

This will reset all jupyter theme changes to default.

Can we pass parameters to a view in SQL?

I realized this task for my needs as follows

set nocount on;

  declare @ToDate date = dateadd(month,datediff(month,0,getdate())-1,0)

declare @year varchar(4)  = year(@ToDate)
declare @month varchar(2) = month(@ToDate)

declare @sql nvarchar(max)
set @sql = N'
    create or alter view dbo.wTempLogs
    as
    select * from dbo.y2019
    where
        year(LogDate) = ''_year_''
        and 
        month(LogDate) = ''_month_''    '

select @sql = replace(replace(@sql,'_year_',@year),'_month_',@month)

execute sp_executesql @sql

declare @errmsg nvarchar(max)
    set @errMsg = @sql
    raiserror (@errMsg, 0,1) with nowait

C# binary literals

C# 7.0 supports binary literals (and optional digit separators via underscore characters).

An example:

int myValue = 0b0010_0110_0000_0011;

You can also find more information on the Roslyn GitHub page.

Java 8 Iterable.forEach() vs foreach loop

One of most upleasing functional forEach's limitations is lack of checked exceptions support.

One possible workaround is to replace terminal forEach with plain old foreach loop:

    Stream<String> stream = Stream.of("", "1", "2", "3").filter(s -> !s.isEmpty());
    Iterable<String> iterable = stream::iterator;
    for (String s : iterable) {
        fileWriter.append(s);
    }

Here is list of most popular questions with other workarounds on checked exception handling within lambdas and streams:

Java 8 Lambda function that throws exception?

Java 8: Lambda-Streams, Filter by Method with Exception

How can I throw CHECKED exceptions from inside Java 8 streams?

Java 8: Mandatory checked exceptions handling in lambda expressions. Why mandatory, not optional?

Turning a Comma Separated string into individual rows

As of Feb 2016 - see the TALLY Table Example - very likely to outperform my TVF below, from Feb 2014. Keeping original post below for posterity:


Too much repeated code for my liking in the above examples. And I dislike the performance of CTEs and XML. Also, an explicit Id so that consumers that are order specific can specify an ORDER BY clause.

CREATE FUNCTION dbo.Split
(
    @Line nvarchar(MAX),
    @SplitOn nvarchar(5) = ','
)
RETURNS @RtnValue table
(
    Id INT NOT NULL IDENTITY(1,1) PRIMARY KEY CLUSTERED,
    Data nvarchar(100) NOT NULL
)
AS
BEGIN
    IF @Line IS NULL RETURN

    DECLARE @split_on_len INT = LEN(@SplitOn)
    DECLARE @start_at INT = 1
    DECLARE @end_at INT
    DECLARE @data_len INT

    WHILE 1=1
    BEGIN
        SET @end_at = CHARINDEX(@SplitOn,@Line,@start_at)
        SET @data_len = CASE @end_at WHEN 0 THEN LEN(@Line) ELSE @end_at-@start_at END
        INSERT INTO @RtnValue (data) VALUES( SUBSTRING(@Line,@start_at,@data_len) );
        IF @end_at = 0 BREAK;
        SET @start_at = @end_at + @split_on_len
    END

    RETURN
END

ES6 class variable alternatives

Since your issue is mostly stylistic (not wanting to fill up the constructor with a bunch of declarations) it can be solved stylistically as well.

The way I view it, many class based languages have the constructor be a function named after the class name itself. Stylistically we could use that that to make an ES6 class that stylistically still makes sense but does not group the typical actions taking place in the constructor with all the property declarations we're doing. We simply use the actual JS constructor as the "declaration area", then make a class named function that we otherwise treat as the "other constructor stuff" area, calling it at the end of the true constructor.

"use strict";

class MyClass
{
    // only declare your properties and then call this.ClassName(); from here
    constructor(){
        this.prop1 = 'blah 1';
        this.prop2 = 'blah 2';
        this.prop3 = 'blah 3';
        this.MyClass();
    }

    // all sorts of other "constructor" stuff, no longer jumbled with declarations
    MyClass() {
        doWhatever();
    }
}

Both will be called as the new instance is constructed.

Sorta like having 2 constructors where you separate out the declarations and the other constructor actions you want to take, and stylistically makes it not too hard to understand that's what is going on too.

I find it's a nice style to use when dealing with a lot of declarations and/or a lot of actions needing to happen on instantiation and wanting to keep the two ideas distinct from each other.


NOTE: I very purposefully do not use the typical idiomatic ideas of "initializing" (like an init() or initialize() method) because those are often used differently. There is a sort of presumed difference between the idea of constructing and initializing. Working with constructors people know that they're called automatically as part of instantiation. Seeing an init method many people are going to assume without a second glance that they need to be doing something along the form of var mc = MyClass(); mc.init();, because that's how you typically initialize. I'm not trying to add an initialization process for the user of the class, I'm trying to add to the construction process of the class itself.

While some people may do a double-take for a moment, that's actually the bit of the point: it communicates to them that the intent is part of construction, even if that makes them do a bit of a double take and go "that's not how ES6 constructors work" and take a second looking at the actual constructor to go "oh, they call it at the bottom, I see", that's far better than NOT communicating that intent (or incorrectly communicating it) and probably getting a lot of people using it wrong, trying to initialize it from the outside and junk. That's very much intentional to the pattern I suggest.


For those that don't want to follow that pattern, the exact opposite can work too. Farm the declarations out to another function at the beginning. Maybe name it "properties" or "publicProperties" or something. Then put the rest of the stuff in the normal constructor.

"use strict";

class MyClass
{
    properties() {
        this.prop1 = 'blah 1';
        this.prop2 = 'blah 2';
        this.prop3 = 'blah 3';
    }

    constructor() {
        this.properties();
        doWhatever();
    }
}

Note that this second method may look cleaner but it also has an inherent problem where properties gets overridden as one class using this method extends another. You'd have to give more unique names to properties to avoid that. My first method does not have this problem because its fake half of the constructor is uniquely named after the class.

Create stacked barplot where each stack is scaled to sum to 100%

You just need to divide each element by the sum of the values in its column.

Doing this should suffice:

data.perc <- apply(data, 2, function(x){x/sum(x)})

Note that the second parameter tells apply to apply the provided function to columns (using 1 you would apply it to rows). The anonymous function, then, gets passed each data column, one at a time.

Error: Cannot invoke an expression whose type lacks a call signature

I had the same error message. In my case I had inadvertently mixed the ES6 export default function myFunc syntax with const myFunc = require('./myFunc');.

Using module.exports = myFunc; instead solved the issue.

Eclipse/Java code completion not working

Check the lib of your project. It may be that you have include two such jar files in which same class is available or say one class in code can be refrenced in two jar files. In such case also eclipse stops assisting code as it is totally confused.

Better way to check this is go to the file where assist is not working and comment all imports there, than add imports one by one and check at each import if code-assist is working or not.You can easily find the class with duplicate refrences.

Tools: replace not replacing in Android manifest

You can replace those in your Manifest application tag:

<application
    tools:replace="android:icon, android:label, android:theme, android:name,android:allowBackup"
android:allowBackup="false"...>

and will work for you.

Positioning background image, adding padding

you can use background-origin:padding-box; and then add some padding where you want, for example: #logo {background-image: url(your/image.jpg); background-origin:padding-box; padding-left: 15%;} This way you attach the image to the div padding box that contains it so you can position it wherever you want.

global variable for all controller and views

Most popular answers here with BaseController didn't worked for me on Laravel 5.4, but they have worked on 5.3. No idea why.

I have found a way which works on Laravel 5.4 and gives variables even for views which are skipping controllers. And, of course, you can get variables from the database.

add in your app/Providers/AppServiceProvider.php

class AppServiceProvider extends ServiceProvider
{
    public function boot()
    {
        // Using view composer to set following variables globally
        view()->composer('*',function($view) {
            $view->with('user', Auth::user());
            $view->with('social', Social::all()); 
            // if you need to access in controller and views:
            Config::set('something', $something); 
        });
    }
}

credit: http://laraveldaily.com/global-variables-in-base-controller/

How do I import an existing Java keystore (.jks) file into a Java installation?

You can bulk import all aliases from one keystore to another:

keytool -importkeystore -srckeystore source.jks -destkeystore dest.jks

MySQL: ignore errors when importing?

Use the --force (-f) flag on your mysql import. Rather than stopping on the offending statement, MySQL will continue and just log the errors to the console.

For example:

mysql -u userName -p -f -D dbName < script.sql

Passing a string array as a parameter to a function java

More than likely your method declaration is incorrect. Make sure the methods parameter is of type String array (String[]) and not simply String and that you use double quotes around your strings in the array declaration.

private String[] stringArray = {"a","b","c","d","e","f","g","h","t","k","k","k"};
public void myMethod(String[] myArray) {}

Figuring out whether a number is a Double in Java

Reflection is slower, but works for a situation when you want to know whether that is of type Dog or a Cat and not an instance of Animal. So you'd do something like:

if(null != items.elementAt(1) && items.elementAt(1).getClass().toString().equals("Cat"))
{
//do whatever with cat.. not any other instance of animal.. eg. hideClaws();
}

Not saying the answer above does not work, except the null checking part is necessary.

Another way to answer that is use generics and you are guaranteed to have Double as any element of items.

List<Double> items = new ArrayList<Double>();

PHP returning JSON to JQUERY AJAX CALL

You can return json in PHP this way:

header('Content-Type: application/json');
echo json_encode(array('foo' => 'bar'));
exit;

Throwing exceptions in a PHP Try Catch block

function _modulename_getData($field, $table) {
  try {
    if (empty($field)) {
      throw new Exception("The field is undefined."); 
    }
    // rest of code here...
  }
  catch (Exception $e) {
    /*
        Here you can either echo the exception message like: 
        echo $e->getMessage(); 

        Or you can throw the Exception Object $e like:
        throw $e;
    */
  }
}

How to fix PHP Warning: PHP Startup: Unable to load dynamic library 'ext\\php_curl.dll'?

If you are using laragon open the php.ini

In the interface of laragon menu-> php-> php.ini

when you open the file look for ; extension_dir = "./"

create another one without **; ** with the path of your php version to the folder ** ext ** for example

extension_dir = "C: \ laragon \ bin \ php \ php-7.3.11-Win32-VC15-x64 \ ext"

change it save it

What's the difference between using "let" and "var"?

let vs var. It's all about scope.

var variables are global and can be accessed basically everywhere, while let variables are not global and only exist until a closing parenthesis kills them.

See my example below, and note how the lion (let) variable acts differently in the two console.logs; it becomes out of scope in the 2nd console.log.

var cat = "cat";
let dog = "dog";

var animals = () => {
    var giraffe = "giraffe";
    let lion = "lion";

    console.log(cat);  //will print 'cat'.
    console.log(dog);  //will print 'dog', because dog was declared outside this function (like var cat).

    console.log(giraffe); //will print 'giraffe'.
    console.log(lion); //will print 'lion', as lion is within scope.
}

console.log(giraffe); //will print 'giraffe', as giraffe is a global variable (var).
console.log(lion); //will print UNDEFINED, as lion is a 'let' variable and is now out of scope.

Copy all the lines to clipboard

This is what I do to yank the whole file:

ggVGy

Scrolling a flexbox with overflowing content

A little late but this could help: http://webdesign.tutsplus.com/tutorials/how-to-make-responsive-scrollable-panels-with-flexbox--cms-23269

Basically you need to put html,body to height: 100%; and wrap all your content into a <div class="wrap"> <!-- content --> </div>

CSS:

html, body {
  height: 100%;
}

.wrap {
  height: 100vh;
  display: flex;
}

Worked for me. Hope it helps

Generate MD5 hash string with T-SQL

Use HashBytes

SELECT HashBytes('MD5', '[email protected]')

That will give you 0xF53BD08920E5D25809DF2563EF9C52B6

-

SELECT CONVERT(NVARCHAR(32),HashBytes('MD5', '[email protected]'),2)

That will give you F53BD08920E5D25809DF2563EF9C52B6

What could cause an error related to npm not being able to find a file? No contents in my node_modules subfolder. Why is that?

If it happens, then it means you have to upgrade your node.js. Simply uninstall your current node from your pc or mac and download the latest version from https://nodejs.org/en/

Python lookup hostname from IP with 1 second timeout

>>> import socket
>>> socket.gethostbyaddr("69.59.196.211")
('stackoverflow.com', ['211.196.59.69.in-addr.arpa'], ['69.59.196.211'])

For implementing the timeout on the function, this stackoverflow thread has answers on that.

Recommended way to insert elements into map

Use insert if you want to insert a new element. insert will not overwrite an existing element, and you can verify that there was no previously exising element:

if ( !myMap.insert( std::make_pair( key, value ) ).second ) {
    //  Element already present...
}

Use [] if you want to overwrite a possibly existing element:

myMap[ key ] = value;
assert( myMap.find( key )->second == value ); // post-condition

This form will overwrite any existing entry.

Generate random integers between 0 and 9

I would try one of the following:

1.> numpy.random.randint

import numpy as np
X1 = np.random.randint(low=0, high=10, size=(15,))

print (X1)
>>> array([3, 0, 9, 0, 5, 7, 6, 9, 6, 7, 9, 6, 6, 9, 8])

2.> numpy.random.uniform

import numpy as np
X2 = np.random.uniform(low=0, high=10, size=(15,)).astype(int)

print (X2)
>>> array([8, 3, 6, 9, 1, 0, 3, 6, 3, 3, 1, 2, 4, 0, 4])

3.> numpy.random.choice

import numpy as np
X3 = np.random.choice(a=10, size=15 )

print (X3)
>>> array([1, 4, 0, 2, 5, 2, 7, 5, 0, 0, 8, 4, 4, 0, 9])

4.> random.randrange

from random import randrange
X4 = [randrange(10) for i in range(15)]

print (X4)
>>> [2, 1, 4, 1, 2, 8, 8, 6, 4, 1, 0, 5, 8, 3, 5]

5.> random.randint

from random import randint
X5 = [randint(0, 9) for i in range(0, 15)]

print (X5)
>>> [6, 2, 6, 9, 5, 3, 2, 3, 3, 4, 4, 7, 4, 9, 6]

Speed:

? np.random.uniform and np.random.randint are much faster (~10 times faster) than np.random.choice, random.randrange, random.randint .

%timeit np.random.randint(low=0, high=10, size=(15,))
>> 1.64 µs ± 7.83 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit np.random.uniform(low=0, high=10, size=(15,)).astype(int)
>> 2.15 µs ± 38.6 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

%timeit np.random.choice(a=10, size=15 )
>> 21 µs ± 629 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)

%timeit [randrange(10) for i in range(15)]
>> 12.9 µs ± 60.4 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

%timeit [randint(0, 9) for i in range(0, 15)]
>> 20 µs ± 386 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

Notes:

1.> np.random.randint generates random integers over the half-open interval [low, high).

2.> np.random.uniform generates uniformly distributed numbers over the half-open interval [low, high).

3.> np.random.choice generates a random sample over the half-open interval [low, high) as if the argument a was np.arange(n).

4.> random.randrange(stop) generates a random number from range(start, stop, step).

5.> random.randint(a, b) returns a random integer N such that a <= N <= b.

6.> astype(int) casts the numpy array to int data type.

7.> I have chosen size = (15,). This will give you a numpy array of length = 15.

No internet on Android emulator - why and how to fix?

If by "use internet", you mean you can not access the internet from an activity while testing on the emulator, make sure you have set the internet permission in your AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" /> 

If you are using the web browser, refer to Donal's post

How to recover MySQL database from .myd, .myi, .frm files

I found a solution for converting the files to a .sql file (you can then import the .sql file to a server and recover the database), without needing to access the /var directory, therefore you do not need to be a server admin to do this either.

It does require XAMPP or MAMP installed on your computer.

  • After you have installed XAMPP, navigate to the install directory (Usually C:\XAMPP), and the the sub-directory mysql\data. The full path should be C:\XAMPP\mysql\data
  • Inside you will see folders of any other databases you have created. Copy & Paste the folder full of .myd, .myi and .frm files into there. The path to that folder should be

    C:\XAMPP\mysql\data\foldername\.mydfiles

  • Then visit localhost/phpmyadmin in a browser. Select the database you have just pasted into the mysql\data folder, and click on Export in the navigation bar. Chooses the export it as a .sql file. It will then pop up asking where the save the file

And that is it! You (should) now have a .sql file containing the database that was originally .myd, .myi and .frm files. You can then import it to another server through phpMyAdmin by creating a new database and pressing 'Import' in the navigation bar, then following the steps to import it

IsNumeric function in c#

Using C# 7 (.NET Framework 4.6.2) you can write an IsNumeric function as a one-liner:

public bool IsNumeric(string val) => int.TryParse(val, out int result);

Note that the function above will only work for integers (Int32). But you can implement corresponding functions for other numeric data types, like long, double, etc.

MySQL ERROR 1045 (28000): Access denied for user 'bill'@'localhost' (using password: YES)

MySQL account names consist of a user name and a host name, The name 'localhost' in host name indicates the local host also You can use the wildcard characters “%” and “_” in host name or IP address values. These have the same meaning as for pattern-matching operations performed with the LIKE operator. For example, a host value of '%' matches any host name, whereas a value of '%.mysql.com' matches any host in the mysql.com domain. '192.168.1.%' matches any host in the 192.168.1 class C network.

Above was just introduction:

actually both users 'bill'@'localhost' and 'bill'@'%' are different MySQL accounts, hence both should use their own authentication details like password.

For more information refer http://dev.mysql.com/doc/refman//5.5/en/account-names.html

Why do package names often begin with "com"

It's just a namespace definition to avoid collision of class names. The com.domain.package.Class is an established Java convention wherein the namespace is qualified with the company domain in reverse.

Convert data.frame column format from character to factor

You could use dplyr::mutate_if() to convert all character columns or dplyr::mutate_at() for select named character columns to factors:

library(dplyr)

# all character columns to factor:
df <- mutate_if(df, is.character, as.factor)

# select character columns 'char1', 'char2', etc. to factor:
df <- mutate_at(df, vars(char1, char2), as.factor)

datetime dtypes in pandas read_csv

You might try passing actual types instead of strings.

import pandas as pd
from datetime import datetime
headers = ['col1', 'col2', 'col3', 'col4'] 
dtypes = [datetime, datetime, str, float] 
pd.read_csv(file, sep='\t', header=None, names=headers, dtype=dtypes)

But it's going to be really hard to diagnose this without any of your data to tinker with.

And really, you probably want pandas to parse the the dates into TimeStamps, so that might be:

pd.read_csv(file, sep='\t', header=None, names=headers, parse_dates=True)

How do I search for names with apostrophe in SQL Server?

First of all my Search query value is from a user's input. I have tried all the answers on this one and all the results Google have given me, 90% of the answers says put '%''%' and the other 10% says a more complicated answers.

For some reason all of those did not work for me.

How ever I remembered that in MySQL (phpmyadmin) there is this built in search function so I tried it just to see how MySQL handles a search with an apostrophe, turns out MySQL just escaping apostrophe with a backslash LIKE '%\'%' so why just I replace apostrophe with a \' in every user's query.

This is what I come up with:

if(!empty($user_search)) {
        $r_user_search = str_ireplace("'","\'","$user_search");
        $find_it = "SELECT * FROM table WHERE column LIKE '%$r_user_search%'";
        $results = $pdo->prepare($find_it);
        $results->execute();

This solves my problem. Also please correct me if this is still has security issues.

Launching an application (.EXE) from C#?

System.Diagnostics.Process.Start("PathToExe.exe");

How to terminate a Python script

import sys
sys.exit()

details from the sys module documentation:

sys.exit([arg])

Exit from Python. This is implemented by raising the SystemExit exception, so cleanup actions specified by finally clauses of try statements are honored, and it is possible to intercept the exit attempt at an outer level.

The optional argument arg can be an integer giving the exit status (defaulting to zero), or another type of object. If it is an integer, zero is considered “successful termination” and any nonzero value is considered “abnormal termination” by shells and the like. Most systems require it to be in the range 0-127, and produce undefined results otherwise. Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors. If another type of object is passed, None is equivalent to passing zero, and any other object is printed to stderr and results in an exit code of 1. In particular, sys.exit("some error message") is a quick way to exit a program when an error occurs.

Since exit() ultimately “only” raises an exception, it will only exit the process when called from the main thread, and the exception is not intercepted.

Note that this is the 'nice' way to exit. @glyphtwistedmatrix below points out that if you want a 'hard exit', you can use os._exit(*errorcode*), though it's likely os-specific to some extent (it might not take an errorcode under windows, for example), and it definitely is less friendly since it doesn't let the interpreter do any cleanup before the process dies. On the other hand, it does kill the entire process, including all running threads, while sys.exit() (as it says in the docs) only exits if called from the main thread, with no other threads running.

SQL SERVER DATETIME FORMAT

This is my favorite use of 112 and 114

select (convert(varchar, getdate(), 112)+ replace(convert(varchar, getdate(), 114),':','')) as 'Getdate() 

112 + 114 or YYYYMMDDHHMMSSMSS'

Result:

Getdate() 112 + 114 or YYYYMMDDHHMMSSMSS

20171016083349100

Selecting only numeric columns from a data frame

Numerical_variables <- which(sapply(df, is.numeric))
# then extract column names 
Names <- names(Numerical_variables)

Delete cookie by name?

//if passed exMins=0 it will delete as soon as it creates it.

function setCookie(cname, cvalue, exMins) {
    var d = new Date();
    d.setTime(d.getTime() + (exMins*60*1000));
    var expires = "expires="+d.toUTCString();  
    document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}

setCookie('cookieNameToDelete','',0) // this will delete the cookie.

Cannot resolve symbol 'AppCompatActivity'

Thats really insane, i tried everything, synced with Gradle files, invalidated and restarted android studio. Still the problem persisted. Last resort was deleting .idea/libraries folder and it worked as charm.

How to pass parameters to a Script tag?

If you are using jquery you might want to consider their data method.

I have used something similar to what you are trying in your response but like this:

<script src="http://path.to/widget.js" param_a = "2" param_b = "5" param_c = "4">
</script>

You could also create a function that lets you grab the GET params directly (this is what I frequently use):

function $_GET(q,s) {
    s = s || window.location.search;
    var re = new RegExp('&'+q+'=([^&]*)','i');
    return (s=s.replace(/^\?/,'&').match(re)) ? s=s[1] : s='';
}

// Grab the GET param
var param_a = $_GET('param_a');

What is the Swift equivalent of respondsToSelector?

As I started to update my old project to Swift 3.2, I just needed to change the method from

respondsToSelector(selector)

to:

responds(to: selector)

Angular CLI - Please add a @NgModule annotation when using latest

In my case, I created a new ChildComponent in Parentcomponent whereas both in the same module but Parent is registered in a shared module so I created ChildComponent using CLI which registered Child in the current module but my parent was registered in the shared module.

So register the ChildComponent in Shared Module manually.

WaitAll vs WhenAll

What do they do:

  • Internally both do the same thing.

What's the difference:

  • WaitAll is a blocking call
  • WhenAll - not - code will continue executing

Use which when:

  • WaitAll when cannot continue without having the result
  • WhenAll when what just to be notified, not blocked

How to use shared memory with Linux in C

try this code sample, I tested it, source: http://www.makelinux.net/alp/035

#include <stdio.h> 
#include <sys/shm.h> 
#include <sys/stat.h> 

int main () 
{
  int segment_id; 
  char* shared_memory; 
  struct shmid_ds shmbuffer; 
  int segment_size; 
  const int shared_segment_size = 0x6400; 

  /* Allocate a shared memory segment.  */ 
  segment_id = shmget (IPC_PRIVATE, shared_segment_size, 
                 IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR); 
  /* Attach the shared memory segment.  */ 
  shared_memory = (char*) shmat (segment_id, 0, 0); 
  printf ("shared memory attached at address %p\n", shared_memory); 
  /* Determine the segment's size. */ 
  shmctl (segment_id, IPC_STAT, &shmbuffer); 
  segment_size  =               shmbuffer.shm_segsz; 
  printf ("segment size: %d\n", segment_size); 
  /* Write a string to the shared memory segment.  */ 
  sprintf (shared_memory, "Hello, world."); 
  /* Detach the shared memory segment.  */ 
  shmdt (shared_memory); 

  /* Reattach the shared memory segment, at a different address.  */ 
  shared_memory = (char*) shmat (segment_id, (void*) 0x5000000, 0); 
  printf ("shared memory reattached at address %p\n", shared_memory); 
  /* Print out the string from shared memory.  */ 
  printf ("%s\n", shared_memory); 
  /* Detach the shared memory segment.  */ 
  shmdt (shared_memory); 

  /* Deallocate the shared memory segment.  */ 
  shmctl (segment_id, IPC_RMID, 0); 

  return 0; 
} 

Get table column names in MySQL?

The MySQL function describe table should get you where you want to go (put your table name in for "table"). You'll have to parse the output some, but it's pretty easy. As I recall, if you execute that query, the PHP query result accessing functions that would normally give you a key-value pair will have the column names as the keys. But it's been a while since I used PHP so don't hold me to that. :)

Button that refreshes the page on click

If you are looking for a form reset:

<input type="reset" value="Reset Form Values"/>

or to reset other aspects of the form not handled by the browser

<input type="reset" onclick="doFormReset();" value="Reset Form Values"/>

Using jQuery

function doFormReset(){
    $(".invalid").removeClass("invalid");
}

bootstrap multiselect get selected values

$('#multiselect1').on('change', function(){
    var selected = $(this).find("option:selected");
    var arrSelected = [];
    selected.each(function(){
       arrSelected.push($(this).val());
    });
});

Could not autowire field:RestTemplate in Spring boot application

If a TestRestTemplate is a valid option in your unit test, this documentation might be relevant

http://docs.spring.io/spring-boot/docs/1.4.1.RELEASE/reference/htmlsingle/#boot-features-rest-templates-test-utility

Short answer: if using

@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)

then @Autowired will work. If using

@SpringBootTest(webEnvironment=WebEnvironment.MOCK)

then create a TestRestTemplate like this

private TestRestTemplate template = new TestRestTemplate();

Streaming a video file to an html5 video player with Node.js so that the video controls continue to work?

Firstly create app.js file in the directory you want to publish.

var http = require('http');
var fs = require('fs');
var mime = require('mime');
http.createServer(function(req,res){
    if (req.url != '/app.js') {
    var url = __dirname + req.url;
        fs.stat(url,function(err,stat){
            if (err) {
            res.writeHead(404,{'Content-Type':'text/html'});
            res.end('Your requested URI('+req.url+') wasn\'t found on our server');
            } else {
            var type = mime.getType(url);
            var fileSize = stat.size;
            var range = req.headers.range;
                if (range) {
                    var parts = range.replace(/bytes=/, "").split("-");
                var start = parseInt(parts[0], 10);
                    var end = parts[1] ? parseInt(parts[1], 10) : fileSize-1;
                    var chunksize = (end-start)+1;
                    var file = fs.createReadStream(url, {start, end});
                    var head = {
                'Content-Range': `bytes ${start}-${end}/${fileSize}`,
                'Accept-Ranges': 'bytes',
                'Content-Length': chunksize,
                'Content-Type': type
                }
                    res.writeHead(206, head);
                    file.pipe(res);
                    } else {    
                    var head = {
                'Content-Length': fileSize,
                'Content-Type': type
                    }
                res.writeHead(200, head);
                fs.createReadStream(url).pipe(res);
                    }
            }
        });
    } else {
    res.writeHead(403,{'Content-Type':'text/html'});
    res.end('Sorry, access to that file is Forbidden');
    }
}).listen(8080);

Simply run node app.js and your server shall be running on port 8080. Besides video it can stream all kinds of files.

How can I remove the first line of a text file using bash/sed script?

For those who are on SunOS which is non-GNU, the following code will help:

sed '1d' test.dat > tmp.dat 

When to use self over $this?

  • The object pointer $this to refers to the current object.
  • The class value static refers to the current object.
  • The class value self refers to the exact class it was defined in.
  • The class value parent refers to the parent of the exact class it was defined in.

See the following example which shows overloading.

<?php

class A {

    public static function newStaticClass()
    {
        return new static;
    }

    public static function newSelfClass()
    {
        return new self;
    }

    public function newThisClass()
    {
        return new $this;
    }
}

class B extends A
{
    public function newParentClass()
    {
        return new parent;
    }
}


$b = new B;

var_dump($b::newStaticClass()); // B
var_dump($b::newSelfClass()); // A because self belongs to "A"
var_dump($b->newThisClass()); // B
var_dump($b->newParentClass()); // A


class C extends B
{
    public static function newSelfClass()
    {
        return new self;
    }
}


$c = new C;

var_dump($c::newStaticClass()); // C
var_dump($c::newSelfClass()); // C because self now points to "C" class
var_dump($c->newThisClass()); // C
var_dump($b->newParentClass()); // A because parent was defined *way back* in class "B"

Most of the time you want to refer to the current class which is why you use static or $this. However, there are times when you need self because you want the original class regardless of what extends it. (Very, Very seldom)

Error in Eclipse: "The project cannot be built until build path errors are resolved"

If not working in any case...then delete your project from the Eclipse workspace and again import as a Maven project if that is a Maven project. Else import as an existing project.

I tried all the previous given solutions, but they didn't work, but it works for me.

AngularJS - ng-if check string empty value

Probably your item.photo is undefined if you don't have a photo attribute on item in the first place and thus undefined != ''. But if you'd put some code to show how you provide values to item, it would help.

PS: Sorry to post this as an answer (I rather think it's more of a comment), but I don't have enough reputation yet.

How do I remove all HTML tags from a string without knowing which tags are in it?

You can use the below code on your string and you will get the complete string without html part.

string title = "<b> Hulk Hogan's Celebrity Championship Wrestling &nbsp;&nbsp;&nbsp;<font color=\"#228b22\">[Proj # 206010]</font></b>&nbsp;&nbsp;&nbsp; (Reality Series, &nbsp;)".Replace("&nbsp;",string.Empty);            
        string s = Regex.Replace(title, "<.*?>", String.Empty);

How to filter a data frame

Another method utilizing the dplyr package:

library(dplyr)
df <- mtcars %>%
        filter(mpg > 25)

Without the chain (%>%) operator:

library(dplyr)
df <- filter(mtcars, mpg > 25)

ASP.NET Web API session or something?

Now in 2017 with ASP.Net Core you can do it as explained here.

The Microsoft.AspNetCore.Session package provides middleware for managing session state.

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
  // Adds a default in-memory implementation of IDistributedCache.
    services.AddDistributedMemoryCache();

    services.AddSession(options =>
    {
        // Set a short timeout for easy testing.
        options.IdleTimeout = TimeSpan.FromSeconds(10);
        options.Cookie.HttpOnly = true;
    });
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UseSession();
}

From the Docs: Introduction to session and application state in ASP.NET Core

Already tested on a working project

How to Correctly Check if a Process is running and Stop it

Thanks @Joey. It's what I am looking for.

I just bring some improvements:

  • to take into account multiple processes
  • to avoid reaching the timeout when all processes have terminated
  • to package the whole in a function

function Stop-Processes {
    param(
        [parameter(Mandatory=$true)] $processName,
                                     $timeout = 5
    )
    $processList = Get-Process $processName -ErrorAction SilentlyContinue
    if ($processList) {
        # Try gracefully first
        $processList.CloseMainWindow() | Out-Null

        # Wait until all processes have terminated or until timeout
        for ($i = 0 ; $i -le $timeout; $i ++){
            $AllHaveExited = $True
            $processList | % {
                $process = $_
                If (!$process.HasExited){
                    $AllHaveExited = $False
                }                    
            }
            If ($AllHaveExited){
                Return
            }
            sleep 1
        }
        # Else: kill
        $processList | Stop-Process -Force        
    }
}

Undefined symbols for architecture arm64

I solved it by setting valid archs to armv7 armv7s and setting build active architectures only to YES in release and then doing a new "pod install" from the command line

Eclipse Indigo - Cannot install Android ADT Plugin

I tried installing and got the same error (using the new "marketplace"). I tried the typical Help->install new software... then where it says "Work with:" I entered:

http://dl-ssl.google.com/android/eclipse/

followed all the prompts and everything seems to be working fine now.

Android - Launcher Icon Size

LDPI should be 36 x 36.

MDPI 48 x 48.

TVDPI 64 x 64.

HDPI 72 x 72.

XHDPI 96 x 96.

XXHDPI 144 x 144.

XXXHDPI 192 x 192.

Controlling fps with requestAnimationFrame?

How to easily throttle to a specific FPS:

// timestamps are ms passed since document creation.
// lastTimestamp can be initialized to 0, if main loop is executed immediately
var lastTimestamp = 0,
    maxFPS = 30,
    timestep = 1000 / maxFPS; // ms for each frame

function main(timestamp) {
    window.requestAnimationFrame(main);

    // skip if timestep ms hasn't passed since last frame
    if (timestamp - lastTimestamp < timestep) return;

    lastTimestamp = timestamp;

    // draw frame here
}

window.requestAnimationFrame(main);

Source: A Detailed Explanation of JavaScript Game Loops and Timing by Isaac Sukin

Combining multiple condition in single case statement in Sql Server

select ROUND(CASE 

WHEN  CONVERT( float, REPLACE( isnull( value1,''),',',''))='' AND CONVERT( float, REPLACE( isnull( value2,''),',',''))='' then  CONVERT( float, REPLACE( isnull( value3,''),',',''))

WHEN  CONVERT( float, REPLACE( isnull( value1,''),',',''))='' AND CONVERT( float, REPLACE( isnull( value2,''),',',''))!='' then  CONVERT( float, REPLACE( isnull( value3,''),',',''))

WHEN  CONVERT( float, REPLACE( isnull( value1,''),',',''))!='' AND CONVERT( float, REPLACE( isnull( value2,''),',',''))='' then  CONVERT( float, REPLACE( isnull( value3,''),',',''))

else CONVERT( float, REPLACE(isnull( value1,''),',','')) end,0)  from Tablename where    ID="123" 

Append an array to another array in JavaScript

If you want to modify the original array instead of returning a new array, use .push()...

array1.push.apply(array1, array2);
array1.push.apply(array1, array3);

I used .apply to push the individual members of arrays 2 and 3 at once.

or...

array1.push.apply(array1, array2.concat(array3));

To deal with large arrays, you can do this in batches.

for (var n = 0, to_add = array2.concat(array3); n < to_add.length; n+=300) {
    array1.push.apply(array1, to_add.slice(n, n+300));
}

If you do this a lot, create a method or function to handle it.

var push_apply = Function.apply.bind([].push);
var slice_call = Function.call.bind([].slice);

Object.defineProperty(Array.prototype, "pushArrayMembers", {
    value: function() {
        for (var i = 0; i < arguments.length; i++) {
            var to_add = arguments[i];
            for (var n = 0; n < to_add.length; n+=300) {
                push_apply(this, slice_call(to_add, n, n+300));
            }
        }
    }
});

and use it like this:

array1.pushArrayMembers(array2, array3);

_x000D_
_x000D_
var push_apply = Function.apply.bind([].push);_x000D_
var slice_call = Function.call.bind([].slice);_x000D_
_x000D_
Object.defineProperty(Array.prototype, "pushArrayMembers", {_x000D_
    value: function() {_x000D_
        for (var i = 0; i < arguments.length; i++) {_x000D_
            var to_add = arguments[i];_x000D_
            for (var n = 0; n < to_add.length; n+=300) {_x000D_
                push_apply(this, slice_call(to_add, n, n+300));_x000D_
            }_x000D_
        }_x000D_
    }_x000D_
});_x000D_
_x000D_
var array1 = ['a','b','c'];_x000D_
var array2 = ['d','e','f'];_x000D_
var array3 = ['g','h','i'];_x000D_
_x000D_
array1.pushArrayMembers(array2, array3);_x000D_
_x000D_
document.body.textContent = JSON.stringify(array1, null, 4);
_x000D_
_x000D_
_x000D_

Datatable select method ORDER BY clause

You can use the below simple method of sorting:

datatable.DefaultView.Sort = "Col2 ASC,Col3 ASC,Col4 ASC";

By the above method, you will be able to sort N number of columns.

Why am I getting a "401 Unauthorized" error in Maven?

As stated in @John's answer, the fact that there is already a 0.1.2-SNAPSHOT, interfered with my new non-SNAPSHOT version 0.1.2. Since the 401 Unauthorized error is nebulous and unhelpful--and is normally associated to user/pass problems--it's no surprise that I was unable to figure this out on my own.

Changing the version to 0.1.3 brings me back to my original error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-install-plugin:2.4:install (default-install) on project xbnjava: Failed to install artifact com.github.aliteralmind:xbnjava:jar:0.1.3: R:\jeffy\programming\build\xbnjava-0.1.3\download\xbnjava-0.1.3-all.jar (The system cannot find the path specified) -> [Help 1].

A sonatype support person also recommended that I remove the <parent> block from my POM (it's only there because it's in the one from ez-vcard, which is what I started with) and replace my <distributionManagement> block with

<distributionManagement>
  <snapshotRepository>
    <id>ossrh</id>
    <url>https://oss.sonatype.org/content/repositories/snapshots</url>
  </snapshotRepository>
  <repository>
    <id>ossrh</id>
    <url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
  </repository>
</distributionManagement>
and then make sure that lines up with what's in your settings.xml:
<settings>
  <servers>
    <server>
      <id>ossrh</id>
      <username>your-jira-id</username>
      <password>your-jira-pwd</password>
    </server>
  </servers>
</settings>

After doing this, running mvn deploy actually uploaded one of my jars for the very first time!!!

Output:

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building XBN-Java 0.1.3
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- build-helper-maven-plugin:1.8:attach-artifact (attach-artifacts) @ xbnjava ---
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ xbnjava ---
[INFO] Installing R:\jeffy\programming\sandbox\z__for_git_commit_only\xbnjava\pom.xml to C:\Users\jeffy\.m2\repository\com\github\aliteralmind\xbnjava\0.1.3\xbnjava-0.1.3.pom
[INFO] Installing R:\jeffy\programming\build\xbnjava-0.1.3\download\xbnjava-0.1.3.jar to C:\Users\jeffy\.m2\repository\com\github\aliteralmind\xbnjava\0.1.3\xbnjava-0.1.3.jar
[INFO]
[INFO] --- maven-deploy-plugin:2.7:deploy (default-deploy) @ xbnjava ---
Uploading: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/0.1.3/xbnjava-0.1.3.pom
2/6 KB
4/6 KB
6/6 KB

Uploaded: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/0.1.3/xbnjava-0.1.3.pom (6 KB at 4.6 KB/sec)
Downloading: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/maven-metadata.xml
310/310 B

Downloaded: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/maven-metadata.xml (310 B at 1.6 KB/sec)
Uploading: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/maven-metadata.xml
310/310 B

Uploaded: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/maven-metadata.xml (310 B at 1.4 KB/sec)
Uploading: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/0.1.3/xbnjava-0.1.3.jar
2/630 KB
4/630 KB
6/630 KB
8/630 KB
10/630 KB
12/630 KB
14/630 KB
...
618/630 KB
620/630 KB
622/630 KB
624/630 KB
626/630 KB
628/630 KB
630/630 KB

(Success portion:)

Uploaded: https://oss.sonatype.org/service/local/staging/deploy/maven2/com/github/aliteralmind/xbnjava/0.1.3/xbnjava-0.1.3.jar (630 KB at 474.7 KB/sec)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.632 s
[INFO] Finished at: 2014-07-18T15:09:25-04:00
[INFO] Final Memory: 6M/19M
[INFO] ------------------------------------------------------------------------

Here's the full updated POM:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.github.aliteralmind</groupId>
  <artifactId>xbnjava</artifactId>
  <packaging>pom</packaging>
  <version>0.1.3</version>
  <name>XBN-Java</name>
  <url>https://github.com/aliteralmind/xbnjava</url>
  <inceptionYear>2014</inceptionYear>
  <organization>
     <name>Jeff Epstein</name>
  </organization>
  <description>XBN-Java is a collection of generically-useful backend (server side, non-GUI) programming utilities, featuring RegexReplacer and FilteredLineIterator. XBN-Java is the foundation of Codelet (http://codelet.aliteralmind.com).</description>

  <licenses>
     <license>
        <name>Lesser General Public License (LGPL) version 3.0</name>
        <url>https://www.gnu.org/licenses/lgpl-3.0.txt</url>
     </license>
     <license>
        <name>Apache Software License (ASL) version 2.0</name>
        <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
     </license>
  </licenses>

  <developers>
     <developer>
        <name>Jeff Epstein</name>
        <email>[email protected]</email>
        <roles>
           <role>Lead Developer</role>
        </roles>
     </developer>
  </developers>

  <issueManagement>
     <system>GitHub Issue Tracker</system>
     <url>https://github.com/aliteralmind/xbnjava/issues</url>
  </issueManagement>

  <distributionManagement>
    <snapshotRepository>
      <id>ossrh</id>
      <url>https://oss.sonatype.org/content/repositories/snapshots</url>
    </snapshotRepository>
    <repository>
      <id>ossrh</id>
      <url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
    </repository>
  </distributionManagement>

  <scm>
     <connection>scm:git:[email protected]:aliteralmind/xbnjava.git</connection>
     <url>scm:git:[email protected]:aliteralmind/xbnjava.git</url>
     <developerConnection>scm:git:[email protected]:aliteralmind/xbnjava.git</developerConnection>
  </scm>

  <properties>
     <java.version>1.7</java.version>
     <jarprefix>R:\jeffy\programming\build\/${project.artifactId}-${project.version}/download/${project.artifactId}-${project.version}</jarprefix>
  </properties>
  <build>
     <plugins>
        <plugin>
           <groupId>org.codehaus.mojo</groupId>
           <artifactId>build-helper-maven-plugin</artifactId>
           <version>1.8</version>
           <executions>
              <execution>
                 <id>attach-artifacts</id>
                 <phase>package</phase>
                 <goals>
                    <goal>attach-artifact</goal>
                 </goals>
                 <configuration>
                    <artifacts>
                       <artifact>
                          <file>${jarprefix}.jar</file>
                          <type>jar</type>
                       </artifact>
                    </artifacts>
                 </configuration>
              </execution>
           </executions>
        </plugin>
     </plugins>
  </build>

  <profiles>
     <!--
     This profile will sign the JAR file, sources file, and javadocs file using the GPG key on the local machine.
     See: https://docs.sonatype.org/display/Repository/How+To+Generate+PGP+Signatures+With+Maven
     -->
     <profile>
        <id>release-sign-artifacts</id>
        <activation>
           <property>
              <name>release</name>
              <value>true</value>
           </property>
        </activation>
     </profile>
  </profiles>
</project>

That's one big Maven problem out of the way. Only 627 more to go.

Java NIO FileChannel versus FileOutputstream performance / usefulness

If you are not using the transferTo feature or non-blocking features you will not notice a difference between traditional IO and NIO(2) because the traditional IO maps to NIO.

But if you can use the NIO features like transferFrom/To or want to use Buffers, then of course NIO is the way to go.