SyntaxFix

Programs & Examples On #L2cap

Bluetooth Logical link control and adaptation protocol resides in the data link layer.

Place input box at the center of div

Here's a rather unconventional way of doing it:

#inputcontainer
{
    display:table-cell; //display like a <td> to make the vertical-align work
    text-align:center; //centre the input horizontally
    vertical-align:middle; //centre the input vertically


    width:200px; //widen the div for demo purposes
    height:200px; //make the div taller for demo purposes
    background:green; //change the background of the div for demo purposes
}

It might not be the best way to do it, and margin? won't work, but it does the job. If you need to use margin, then you could wrap the div that displays as a table cell in another 'normal' div.

JSFiddle: http://jsfiddle.net/qw4QW/

How to link html pages in same or different folders?

This worked for me <a href="preferedfile name.html">to be clicked <a/>

How to set top position using jquery

You can use CSS to do the trick:

$("#yourElement").css({ top: '100px' });

Checking if float is an integer

Apart from the fine answers already given, you can also use ceilf(f) == f or floorf(f) == f. Both expressions return true if f is an integer. They also returnfalse for NaNs (NaNs always compare unequal) and true for ±infinity, and don't have the problem with overflowing the integer type used to hold the truncated result, because floorf()/ceilf() return floats.

django - get() returned more than one topic

Get is supposed to return, one and exactly one record, to fix this use filter(), and then take first element of the queryset returned to get the object you were expecting from get, also it would be useful to check if atleast one record is returned before taking out the first element to avoid IndexError

Extracting substrings in Go

Go strings are not null terminated, and to remove the last char of a string you can simply do:

s = s[:len(s)-1]

Printing Batch file results to a text file

There's nothing wrong with your redirection of standard out to a file. Move and mkdir commands do not output anything. If you really need to have a log trail of those commands, then you'll need to explicitly echo to standard out indicating what you just executed.

The batch file, example:

@ECHO OFF
cd bob
ECHO I just did this: cd bob

Run from command line:

myfile.bat >> out.txt

or

myfile.bat > out.txt

Null check in VB

Change your Ands to AndAlsos

A standard And will test both expressions. If comp.Container is Nothing, then the second expression will raise a NullReferenceException because you're accessing a property on a null object.

AndAlso will short-circuit the logical evaluation. If comp.Container is Nothing, then the 2nd expression will not be evaluated.

How can I get onclick event on webview in android?

I have tried almost all the answers and some of them almost worked for me but none of these answers work perfectly. So here is my solution. For this solution, you will need to add onclick attribute in the HTML body tag. So if you can not modify the HTML file then this solution won't work for you.

Step 1: add onclick attribute in the HTML body tag like this:

<body onclick="ok.performClick(this.value);">
    <h1>This is heading 1</h1>
    <p>This is para 1</p>
</body>

Step 2: implement addJavascriptInterface in your app to handle click listener:

webView.addJavascriptInterface(new Object() {
    @JavascriptInterface
    public void performClick(String string) {
        handler.sendEmptyMessageDelayed(CLICK_ON_WEBVIEW, 0);
    }
}, "ok");

Step 3: We can not perform any action on main thread from performClick method so need to add Handler class:

private final Handler handler = new Handler(this); // class-level variable 
private static final int CLICK_ON_WEBVIEW = 1; // class-level variable

implement Handler.Callback to your class and the override handleMessage

@Override
public boolean handleMessage(Message message) {
    if (message.what == CLICK_ON_WEBVIEW) {
        Toast.makeText(getActivity(), "WebView clicked", Toast.LENGTH_SHORT).show();
        return true;
    }
    return false;
}

How to Lock the data in a cell in excel using vba

Let's say for example in one case, if you want to locked cells from range A1 to I50 then below is the code:

Worksheets("Enter your sheet name").Range("A1:I50").Locked = True
ActiveSheet.Protect Password:="Enter your Password"

In another case if you already have a protected sheet then follow below code:

ActiveSheet.Unprotect Password:="Enter your Password"
Worksheets("Enter your sheet name").Range("A1:I50").Locked = True
ActiveSheet.Protect Password:="Enter your Password"

CakePHP find method with JOIN

 
        $services = $this->Service->find('all', array(
            'limit' =>4,
            'fields' => array('Service.*','ServiceImage.*'),
            'joins' => array(
                array(
                        'table' => 'services_images',
                        'alias' => 'ServiceImage',
                        'type' => 'INNER',
                        'conditions' => array(
                        'ServiceImage.service_id' =>'Service.id'
                        )
                    ),
                ),
            )
        );

It goges to array is null.

Maximum size of an Array in Javascript

Like @maerics said, your target machine and browser will determine performance.

But for some real world numbers, on my 2017 enterprise Chromebook, running the operation:

console.time();
Array(x).fill(0).filter(x => x < 6).length
console.timeEnd();
  • x=5e4 takes 16ms, good enough for 60fps
  • x=4e6 takes 250ms, which is noticeable but not a big deal
  • x=3e7 takes 1300ms, which is pretty bad
  • x=4e7 takes 11000ms and allocates an extra 2.5GB of memory

So around 30 million elements is a hard upper limit, because the javascript VM falls off a cliff at 40 million elements and will probably crash the process.

EDIT: In the code above, I'm actually filling the array with elements and looping over them, simulating the minimum of what an app might want to do with an array. If you just run Array(2**32-1) you're creating a sparse array that's closer to an empty JavaScript object with a length, like {length: 4294967295}. If you actually tried to use all those 4 billion elements, you'll definitely your user's javascript process.

How to find a value in an excel column by vba code Cells.Find

Just use

Dim Cell As Range
Columns("B:B").Select
Set cell = Selection.Find(What:="celda", After:=ActiveCell, LookIn:=xlFormulas, _
        LookAt:=xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
        MatchCase:=False, SearchFormat:=False)

If cell Is Nothing Then
    'do it something

Else
    'do it another thing
End If

Make div fill remaining space along the main axis in flexbox

Use the flex-grow property to make a flex item consume free space on the main axis.

This property will expand the item as much as possible, adjusting the length to dynamic environments, such as screen re-sizing or the addition / removal of other items.

A common example is flex-grow: 1 or, using the shorthand property, flex: 1.

Hence, instead of width: 96% on your div, use flex: 1.

You wrote:

So at the moment, it's set to 96% which looks OK until you really squash the screen - then the right hand div gets a bit starved of the space it needs.

The squashing of the fixed-width div is related to another flex property: flex-shrink

By default, flex items are set to flex-shrink: 1 which enables them to shrink in order to prevent overflow of the container.

To disable this feature use flex-shrink: 0.

For more details see The flex-shrink factor section in the answer here:

Learn more about flex alignment along the main axis here:

Learn more about flex alignment along the cross axis here:

How do I make a fixed size formatted string in python?

Sure, use the .format method. E.g.,

print('{:10s} {:3d}  {:7.2f}'.format('xxx', 123, 98))
print('{:10s} {:3d}  {:7.2f}'.format('yyyy', 3, 1.0))
print('{:10s} {:3d}  {:7.2f}'.format('zz', 42, 123.34))

will print

xxx        123    98.00
yyyy         3     1.00
zz          42   123.34

You can adjust the field sizes as desired. Note that .format works independently of print to format a string. I just used print to display the strings. Brief explanation:

10s format a string with 10 spaces, left justified by default

3d format an integer reserving 3 spaces, right justified by default

7.2f format a float, reserving 7 spaces, 2 after the decimal point, right justfied by default.

There are many additional options to position/format strings (padding, left/right justify etc), String Formatting Operations will provide more information.

Update for f-string mode. E.g.,

text, number, other_number = 'xxx', 123, 98
print(f'{text:10} {number:3d}  {other_number:7.2f}')

For right alignment

print(f'{text:>10} {number:3d}  {other_number:7.2f}')

What's the difference between "Layers" and "Tiers"?

Why always trying to use complex words?

A layer = a part of your code, if your application is a cake, this is a slice.

A tier = a physical machine, a server.

A tier hosts one or more layers.

Example of layers:

  • Presentation layer = usually all the code related to the User Interface
  • Data Access layer = all the code related to your database access

Tier:

Your code is hosted on a server = Your code is hosted on a tier.

Your code is hosted on 2 servers = Your code is hosted on 2 tiers.

For example, one machine hosting the Web Site itself (the Presentation layer), another machine more secured hosting all the more security sensitive code (real business code - business layer, database access layer, etc.).

There are so many benefits to implement a layered architecture. This is tricky and properly implementing a layered application takes time. If you have some, have a look at this post from Microsoft: http://msdn.microsoft.com/en-gb/library/ee658109.aspx

How to get all enum values in Java?

values method of enum

enum.values() method which returns all enum instances.

  public class EnumTest {
        private enum Currency {
        PENNY("1 rs"), NICKLE("5 rs"), DIME("10 rs"), QUARTER("25 rs");
        private String value;
        private Currency(String brand) {
              this.value = brand;
        }

        @Override
        public String toString() {
              return value;
        }
  }

  public static void main(String args[]) {

        Currency[] currencies = Currency.values();

        // enum name using name method
        // enum to String using toString() method
        for (Currency currency : currencies) {
              System.out.printf("[ Currency : %s,
                         Value : %s ]%n",currency.name(),currency);
        }
  }
}

http://javaexplorer03.blogspot.in/2015/10/name-and-values-method-of-enum.html

How do I get console input in javascript?

You can try something like process.argv, that is if you are using node.js to run the program.
console.log(process.argv) => Would print an array containing

[                                                                                                                                                                                          
  '/usr/bin/node',                                                                                                                                                                         
  '/home/user/path/filename.js',                                                                                                                                            
  'your_input'                                                                                                                                                                                   
]

You get the user provided input via array index, i.e., console.log(process.argv[3]) This should provide you with the input which you can store.


Example:

var somevariable = process.argv[3]; // input one
var somevariable2 = process.argv[4]; // input two

console.log(somevariable);
console.log(somevariable2);

If you are building a command-line program then the npm package yargs would be really helpful.

How to change background and text colors in Sublime Text 3

This question -- Why do Sublime Text 3 Themes not affect the sidebar? -- helped me out.

The steps I followed:

  1. Preferences
  2. Browse Packages...
  3. Go into the User folder (equivalent to going to %AppData%\Sublime Text 3\Packages\User)
  4. Make a new text file in this folder called Default.sublime-theme
  5. Add JSON styles here -- for a template, check out https://gist.github.com/MrDrews/5434948

Using NULL in C++?

I never use NULL in my C or C++ code. 0 works just fine, as does if (ptrname). Any competent C or C++ programmer should know what those do.

How to convert WebResponse.GetResponseStream return into a string?

Richard Schneider is right. use code below to fetch data from site which is not utf8 charset will get wrong string.

using (Stream stream = response.GetResponseStream())
{
   StreamReader reader = new StreamReader(stream, Encoding.UTF8);
   String responseString = reader.ReadToEnd();
}

" i can't vote.so wrote this.

Generate random numbers following a normal distribution in C/C++

I created a C++ open source project for normally distributed random number generation benchmark.

It compares several algorithms, including

  • Central limit theorem method
  • Box-Muller transform
  • Marsaglia polar method
  • Ziggurat algorithm
  • Inverse transform sampling method.
  • cpp11random uses C++11 std::normal_distribution with std::minstd_rand (it is actually Box-Muller transform in clang).

The results of single-precision (float) version on iMac [email protected] , clang 6.1, 64-bit:

normaldistf

For correctness, the program verifies the mean, standard deviation, skewness and kurtosis of the samples. It was found that CLT method by summing 4, 8 or 16 uniform numbers do not have good kurtosis as the other methods.

Ziggurat algorithm has better performance than the others. However, it does not suitable for SIMD parallelism as it needs table lookup and branches. Box-Muller with SSE2/AVX instruction set is much faster (x1.79, x2.99) than non-SIMD version of ziggurat algorithm.

Therefore, I will suggest using Box-Muller for architecture with SIMD instruction sets, and may be ziggurat otherwise.

P.S. the benchmark uses a simplest LCG PRNG for generating uniform distributed random numbers. So it may not be sufficient for some applications. But the performance comparison should be fair because all implementations uses the same PRNG, so the benchmark mainly tests the performance of the transformation.

MySQL my.cnf performance tuning recommendations

Try starting with the Percona wizard and comparing their recommendations against your current settings one by one. Don't worry there aren't as many applicable settings as you might think.

https://tools.percona.com/wizard

Update circa 2020: Sorry, this tool reached it's end of life: https://www.percona.com/blog/2019/04/22/end-of-life-query-analyzer-and-mysql-configuration-generator/

Everyone points to key_buffer_size first which you have addressed. With 96GB memory I'd be wary of any tiny default value (likely to be only 96M!).

Could not load file or assembly "System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"

In one of my projects there was a nuget packages with higher version of System.Net.Http. and in my startup project there reference to System.Net.Http v 4.0.0 , i just installed System.Net.Http nuget package in my startup project and the problem solved

Why can't C# interfaces contain fields?

Others have given the 'Why', so I'll just add that your interface can define a Control; if you wrap it in a property:

public interface IView {
    Control Year { get; }
}


public Form : IView {
    public Control Year { get { return uxYear; } } //numeric text box or whatever
}

Setting button text via javascript

Create a text node and append it to the button element:

var t = document.createTextNode("test content");
b.appendChild(t);

Incrementing a date in JavaScript

Two methods:

1:

var a = new Date()
// no_of_days is an integer value
var b = new Date(a.setTime(a.getTime() + no_of_days * 86400000)

2: Similar to the previous method

var a = new Date()
// no_of_days is an integer value
var b = new Date(a.setDate(a.getDate() + no_of_days)

pandas: How do I split text in a column into multiple rows?

Differently from Dan, I consider his answer quite elegant... but unfortunately it is also very very inefficient. So, since the question mentioned "a large csv file", let me suggest to try in a shell Dan's solution:

time python -c "import pandas as pd;
df = pd.DataFrame(['a b c']*100000, columns=['col']);
print df['col'].apply(lambda x : pd.Series(x.split(' '))).head()"

... compared to this alternative:

time python -c "import pandas as pd;
from scipy import array, concatenate;
df = pd.DataFrame(['a b c']*100000, columns=['col']);
print pd.DataFrame(concatenate(df['col'].apply( lambda x : [x.split(' ')]))).head()"

... and this:

time python -c "import pandas as pd;
df = pd.DataFrame(['a b c']*100000, columns=['col']);
print pd.DataFrame(dict(zip(range(3), [df['col'].apply(lambda x : x.split(' ')[i]) for i in range(3)]))).head()"

The second simply refrains from allocating 100 000 Series, and this is enough to make it around 10 times faster. But the third solution, which somewhat ironically wastes a lot of calls to str.split() (it is called once per column per row, so three times more than for the others two solutions), is around 40 times faster than the first, because it even avoids to instance the 100 000 lists. And yes, it is certainly a little ugly...

EDIT: this answer suggests how to use "to_list()" and to avoid the need for a lambda. The result is something like

time python -c "import pandas as pd;
df = pd.DataFrame(['a b c']*100000, columns=['col']);
print pd.DataFrame(df.col.str.split().tolist()).head()"

which is even more efficient than the third solution, and certainly much more elegant.

EDIT: the even simpler

time python -c "import pandas as pd;
df = pd.DataFrame(['a b c']*100000, columns=['col']);
print pd.DataFrame(list(df.col.str.split())).head()"

works too, and is almost as efficient.

EDIT: even simpler! And handles NaNs (but less efficient):

time python -c "import pandas as pd;
df = pd.DataFrame(['a b c']*100000, columns=['col']);
print df.col.str.split(expand=True).head()"

build failed with: ld: duplicate symbol _OBJC_CLASS_$_Algebra5FirstViewController

I found this article that provided a solution for me. It pertains to Xcode 7 where the default for No Common Blocks is Yes rather than No in previous versions.

This is a quote from the article:

The problem seems to be that the "No common blocks" in the "Apple LLVM 6.1 - Code Generation" section in the Build settings pane is set to Yes, in the latest version of Xcode.

This caused what I will describe as circular references where a class that was included in my Compile Sources was referenced via a #import in another source file (appDelegate.m). This caused duplicate blocks for variables that were declared in the original base class.

Changing the value to No immediately enabled my app to compile and resolved my problem.

Plotting a fast Fourier transform in Python

There are already great solutions on this page, but all have assumed the dataset is uniformly/evenly sampled/distributed. I will try to provide a more general example of randomly sampled data. I will also use this MATLAB tutorial as an example:

Adding the required modules:

import numpy as np
import matplotlib.pyplot as plt
import scipy.fftpack
import scipy.signal

Generating sample data:

N = 600 # Number of samples
t = np.random.uniform(0.0, 1.0, N) # Assuming the time start is 0.0 and time end is 1.0
S = 1.0 * np.sin(50.0 * 2 * np.pi * t) + 0.5 * np.sin(80.0 * 2 * np.pi * t)
X = S + 0.01 * np.random.randn(N) # Adding noise

Sorting the data set:

order = np.argsort(t)
ts = np.array(t)[order]
Xs = np.array(X)[order]

Resampling:

T = (t.max() - t.min()) / N # Average period
Fs = 1 / T # Average sample rate frequency
f = Fs * np.arange(0, N // 2 + 1) / N; # Resampled frequency vector
X_new, t_new = scipy.signal.resample(Xs, N, ts)

Plotting the data and resampled data:

plt.xlim(0, 0.1)
plt.plot(t_new, X_new, label="resampled")
plt.plot(ts, Xs, label="org")
plt.legend()
plt.ylabel("X")
plt.xlabel("t")

Enter image description here

Now calculating the FFT:

Y = scipy.fftpack.fft(X_new)
P2 = np.abs(Y / N)
P1 = P2[0 : N // 2 + 1]
P1[1 : -2] = 2 * P1[1 : -2]

plt.ylabel("Y")
plt.xlabel("f")
plt.plot(f, P1)

Enter image description here

P.S. I finally got time to implement a more canonical algorithm to get a Fourier transform of unevenly distributed data. You may see the code, description, and example Jupyter notebook here.

Call JavaScript function on DropDownList SelectedIndexChanged Event:

First Method: (Tested)

Code in .aspx.cs:

 protected void Page_Load(object sender, EventArgs e)
    {
        ddl.SelectedIndexChanged += new EventHandler(ddl_SelectedIndexChanged);
        if (!Page.IsPostBack)
        {
            ddl.Attributes.Add("onchange", "CalcTotalAmt();");
        }
    }

    protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
    {
       //Your Code
    }

JavaScript function: return true from your JS function

   function CalcTotalAmt() 
 {
//Your Code
 }

.aspx code:

<asp:DropDownList ID="ddl" runat="server"  AutoPostBack="true">
        <asp:ListItem Text="a" Value="a"></asp:ListItem>
         <asp:ListItem Text="b" Value="b"></asp:ListItem>
        </asp:DropDownList>

Second Method: (Tested)

Code in .aspx.cs:

protected void Page_Load(object sender, EventArgs e)
        {
            if (Request.Params["__EVENTARGUMENT"] != null && Request.Params["__EVENTARGUMENT"].Equals("ddlchange"))
                ddl_SelectedIndexChanged(sender, e);
            if (!Page.IsPostBack)
            {
                ddl.Attributes.Add("onchange", "CalcTotalAmt();");
            }
        }

        protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
        {
            //Your Code
        }

JavaScript function: return true from your JS function

function CalcTotalAmt() {
         //Your Code
     __doPostBack("ctl00$MainContent$ddl","ddlchange");
 }

.aspx code:

<asp:DropDownList ID="ddl" runat="server"  AutoPostBack="true">
        <asp:ListItem Text="a" Value="a"></asp:ListItem>
         <asp:ListItem Text="b" Value="b"></asp:ListItem>
        </asp:DropDownList>

QuotaExceededError: Dom exception 22: An attempt was made to add something to storage that exceeded the quota

This can occur when Safari is in private mode browsing. While in private browsing, local storage is not available at all.

One solution is to warn the user that the app needs non-private mode to work.

UPDATE: This has been fixed in Safari 11, so the behaviour is now aligned with other browsers.

Create a BufferedImage from file and make it TYPE_INT_ARGB

Create a BufferedImage from file and make it TYPE_INT_RGB

import java.io.*;
import java.awt.image.*;
import javax.imageio.*;
public class Main{
    public static void main(String args[]){
        try{
            BufferedImage img = new BufferedImage( 
                500, 500, BufferedImage.TYPE_INT_RGB );
            File f = new File("MyFile.png");
            int r = 5;
            int g = 25; 
            int b = 255;
            int col = (r << 16) | (g << 8) | b;
            for(int x = 0; x < 500; x++){
                for(int y = 20; y < 300; y++){
                    img.setRGB(x, y, col);
                }
            }
            ImageIO.write(img, "PNG", f); 
        }
        catch(Exception e){ 
            e.printStackTrace();
        }
    }
}

This paints a big blue streak across the top.

If you want it ARGB, do it like this:

    try{
        BufferedImage img = new BufferedImage( 
            500, 500, BufferedImage.TYPE_INT_ARGB );
        File f = new File("MyFile.png");
        int r = 255;
        int g = 10;
        int b = 57;
        int alpha = 255;
        int col = (alpha << 24) | (r << 16) | (g << 8) | b;
        for(int x = 0; x < 500; x++){
            for(int y = 20; y < 30; y++){
                img.setRGB(x, y, col);
            }
        }
        ImageIO.write(img, "PNG", f);
    }
    catch(Exception e){
        e.printStackTrace();
    }

Open up MyFile.png, it has a red streak across the top.

How to show DatePickerDialog on Button click?

 
    final Calendar newCalendar = Calendar.getInstance();
    final DatePickerDialog  StartTime = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {
                public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                    Calendar newDate = Calendar.getInstance();
                    newDate.set(year, monthOfYear, dayOfMonth);
                    activitydate.setText(dateFormatter.format(newDate.getTime()));
                }
    
            }, newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH));
    
      btn_checkin.setOnClickListener(new View.OnClickListener() {
@Override   public void onClick(View v) {
         StartTime.show():    
     });

Android Studio emulator does not come with Play Store for API 23

Wanted to comment on the last answer, but without login it’s only possible to make an answer:

To get rid of the "read only error" just stop the device immediately after it’s ready. My script looks as follows:

#!/bin/bash 
~/bin/AndroidSdk/tools/emulator @Nexus_6P_API_23 -no-boot-anim &
adb wait-for-device
adb shell stop
adb remount
adb push GmsCore.apk /system/priv-app
adb push GoogleServicesFramework.apk /system/priv-app
adb push GoogleLoginService.apk /system/priv-app
adb push Phonesky.apk /system/priv-app
adb shell start

How to write multiple conditions of if-statement in Robot Framework

You should use small caps "or" and "and" instead of OR and AND.

And beware also the spaces/tabs between keywords and arguments (you need at least two spaces).

Here is a code sample with your three keywords working fine:

Here is the file ts.txt:

  *** test cases ***
  mytest
    ${color} =  set variable  Red
    Run Keyword If  '${color}' == 'Red'  log to console  \nexecuted with single condition
    Run Keyword If  '${color}' == 'Red' or '${color}' == 'Blue' or '${color}' == 'Pink'  log to console  \nexecuted with multiple or

    ${color} =  set variable  Blue
    ${Size} =  set variable  Small
    ${Simple} =  set variable  Simple
    ${Design} =  set variable  Simple
    Run Keyword If  '${color}' == 'Blue' and '${Size}' == 'Small' and '${Design}' != '${Simple}'  log to console  \nexecuted with multiple and

    ${Size} =  set variable  XL
    ${Design} =  set variable  Complicated
    Run Keyword Unless  '${color}' == 'Black' or '${Size}' == 'Small' or '${Design}' == 'Simple'  log to console  \nexecuted with unless and multiple or

and here is what I get when I execute it:

$ pybot ts.txt
==============================================================================
Ts
==============================================================================
mytest                                                                .
executed with single condition
executed with multiple or
executed with unless and multiple or
mytest                                                                | PASS |
------------------------------------------------------------------------------

password-check directive in angularjs

As of angular 1.3.0-beta12, invalid inputs don't write to ngModel, so you can't watch AND THEN validate as you can see here: http://plnkr.co/edit/W6AFHF308nyKVMQ9vomw?p=preview. A new validators pipeline was introduced and you can attach to this to achieve the same thing.

Actually, on that note I've created a bower component for common extra validators: https://github.com/intellix/angular-validators which includes this.

angular.module('validators').directive('equals', function() {
    return {
        restrict: 'A',
        require: '?ngModel',
        link: function(scope, elem, attrs, ngModel)
        {
            if (!ngModel) return;

            attrs.$observe('equals', function() {
                ngModel.$validate();
            });

            ngModel.$validators.equals = function(value) {
                return value === attrs.equals;
            };
        }
    };
});

angular.module('validators').directive('notEquals', function() {
    return {
        restrict: 'A',
        require: '?ngModel',
        link: function(scope, elem, attrs, ngModel)
        {
            if (!ngModel) return;

            attrs.$observe('notEquals', function() {
                ngModel.$validate();
            });

            ngModel.$validators.notEquals = function(value) {
                return value === attrs.notEquals;
            };
        }
    };
});

Get week number (in the year) from a date PHP

 
function last_monday($date) 
{
    if (!is_numeric($date))
        $date = strtotime($date);
    if (date('w', $date) == 1)
        return $date;
    else
        return date('Y-m-d',strtotime('last monday',$date));
}
$date = '2021-01-04';  //Enter custom date
$year = date('Y',strtotime($date));
$date1 = new DateTime($date);
$ldate = last_monday($year."-01-01");
$date2 = new DateTime($ldate);
$diff = $date2->diff($date1)->format("%a");
$diff = $diff/7;
$week = intval($diff) + 1;
echo $week;
//Returns 2.

What is the problem with shadowing names defined in outer scopes?

It depends how long the function is. The longer the function, the greater the chance that someone modifying it in future will write data thinking that it means the global. In fact, it means the local, but because the function is so long, it's not obvious to them that there exists a local with that name.

For your example function, I think that shadowing the global is not bad at all.

Count if two criteria match - EXCEL formula

Add the sheet name infront of the cell, e.g.:

=COUNTIFS(stock!A:A,"M",stock!C:C,"Yes")

Assumes the sheet name is "stock"

What exactly is std::atomic?

I understand that std::atomic<> makes an object atomic.

That's a matter of perspective... you can't apply it to arbitrary objects and have their operations become atomic, but the provided specialisations for (most) integral types and pointers can be used.

a = a + 12;

std::atomic<> does not (use template expressions to) simplify this to a single atomic operation, instead the operator T() const volatile noexcept member does an atomic load() of a, then twelve is added, and operator=(T t) noexcept does a store(t).

Unclosed Character Literal error

String y = "hello";

would work (note the double quotes).

char y = 'h'; this will work for chars (note the single quotes)

but the type is the key: '' (single quotes) for one char, "" (double quotes) for string.

How to retrieve value from elements in array using jQuery?

Your syntax is incorrect.

card_value = $(array[i]).val(); or card_value = array[i].value;

array[i] is not a jQuery object (for some reason).

Checking your browser's console can be helpful for things like this.

Copy array by value

If you are in an environment of ECMAScript 6, using the Spread Operator you could do it this way:

_x000D_
_x000D_ 
var arr1 = ['a','b','c'];_x000D_
var arr2 = [...arr1]; //copy arr1_x000D_
arr2.push('d');_x000D_
_x000D_
console.log(arr1)_x000D_
console.log(arr2)
_x000D_ 
<script src="http://www.wzvang.com/snippet/ignore_this_file.js"></script>
_x000D_
_x000D_
_x000D_

A python class that acts like dict

A python class that acts like dict

By request - adding slots to a dict subclass.

Why add slots? A builtin dict instance doesn't have arbitrary attributes:

>>> d = dict()
>>> d.foo = 'bar'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'dict' object has no attribute 'foo'

If we create a subclass the way most are doing it here on this answer, we see we don't get the same behavior, because we'll have a __dict__ attribute, causing our dicts to take up to potentially twice the space:

my_dict(dict):
    """my subclass of dict""" 

md = my_dict()
md.foo = 'bar'

Since there's no error created by the above, the above class doesn't actually act, "like dict."

We can make it act like dict by giving it empty slots:

class my_dict(dict):
    __slots__ = ()

md = my_dict()

So now attempting to use arbitrary attributes will fail:

>>> md.foo = 'bar'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'my_dict' object has no attribute 'foo'

And this Python class acts more like a dict.

For more on how and why to use slots, see this Q&A: Usage of __slots__?

Passing parameters to a JDBC PreparedStatement

You should use the setString() method to set the userID. This both ensures that the statement is formatted properly, and prevents SQL injection: 

statement =con.prepareStatement("SELECT * from employee WHERE  userID = ?");
statement.setString(1, userID);

There is a nice tutorial on how to use PreparedStatements properly in the Java Tutorials.

Android Studio error: "Environment variable does not point to a valid JVM installation"

If you start 64bit Android Studio, you have to add JAVA_HOME as

    "C:\Program Files\Java\jdk..."

If 32bit

    "C:\Program Files(x86)\Java\jdk..."

and dont put "\bin" end of the path.

Switch to another branch without changing the workspace files

Git. Switch to another branch

git checkout branch_name

Bootstrap modal: close current, open new

I use this method:

$(function() {
  return $(".modal").on("show.bs.modal", function() {
    var curModal;
    curModal = this;
    $(".modal").each(function() {
      if (this !== curModal) {
        $(this).modal("hide");
      }
    });
  });
});

Load and execution sequence of a web page?

Dynatrace AJAX Edition shows you the exact sequence of page loading, parsing and execution.

Delay/Wait in a test case of Xcode UI testing

In my case sleep created side effect so I used wait

let _ = XCTWaiter.wait(for: [XCTestExpectation(description: "Hello World!")], timeout: 2.0)

Interview Question: Merge two sorted singly linked lists without creating new nodes

 
Node MergeLists(Node list1, Node list2) {
  if (list1 == null) return list2;
  if (list2 == null) return list1;

  if (list1.data < list2.data) {
    list1.next = MergeLists(list1.next, list2);
    return list1;
  } else {
    list2.next = MergeLists(list2.next, list1);
    return list2;
  }
}

Sum rows in data.frame or matrix

you can use rowSums

rowSums(data) should give you what you want.

What is the `zero` value for time.Time in Go?

You should use the Time.IsZero() function instead:

func (Time) IsZero

func (t Time) IsZero() bool
IsZero reports whether t represents the zero time instant, January 1, year 1, 00:00:00 UTC.

Delete newline in Vim

I would just press A (append to end of line, puts you into insert mode) on the line where you want to remove the newline and then press delete.

How can you represent inheritance in a database?

In addition at the Daniel Vassallo solution, if you use SQL Server 2016+, there is another solution that I used in some cases without considerable lost of performances.

You can create just a table with only the common field and add a single column with the JSON string that contains all the subtype specific fields.

I have tested this design for manage inheritance and I am very happy for the flexibility that I can use in the relative application.

regular expression to validate datetime format (MM/DD/YYYY)

It's long, but great:

new RegExp(/(?=\d)^(?:(?!(?:10\D(?:0?[5-9]|1[0-4])\D(?:1582))|(?:0?9\D(?:0?[3-9]|1[0-3])\D(?:1752)))((?:0?[13578]|1[02])|(?:0?[469]|11)(?!\/31)(?!-31)(?!\.31)|(?:0?2(?=.?(?:(?:29.(?!000[04]|(?:(?:1[^0-6]|[2468][^048]|[3579][^26])00))(?:(?:(?:\d\d)(?:[02468][048]|[13579][26])(?!\x20BC))|(?:00(?:42|3[0369]|2[147]|1[258]|09)\x20BC))))))|(?:0?2(?=.(?:(?:\d\D)|(?:[01]\d)|(?:2[0-8])))))([-.\/])(0?[1-9]|[12]\d|3[01])\2(?!0000)((?=(?:00(?:4[0-5]|[0-3]?\d)\x20BC)|(?:\d{4}(?!\x20BC)))\d{4}(?:\x20BC)?)(?:$|(?=\x20\d)\x20))?((?:(?:0?[1-9]|1[012])(?::[0-5]\d){0,2}(?:\x20[aApP][mM]))|(?:[01]\d|2[0-3])(?::[0-5]\d){1,2})?$/);

What is polymorphism, what is it for, and how is it used?

Polymorphism allows the same routine (function, method) to act on different types.

Since many existing answers are conflating subtyping with polymorphism, here are three ways (including subtyping) to implement polymorphism.

  • Parameteric (generic) polymorphism allows a routine to accept one or more type parameters, in addition to normal parameters, and runs itself on those types.
  • Subtype polymorphism allows a routine to act on any subtype of its parameters.
  • Ad hoc polymorphism generally uses routine overloading to grant polymorphic behavior, but can refer to other polymorphism implementations too.

See also:

http://wiki.c2.com/?CategoryPolymorphism

https://en.wikipedia.org/wiki/Polymorphism_(computer_science)

What is a reasonable length limit on person "Name" fields?

Note that many cultures have 'second surnames' often called family names. For example, if you are dealing with Spanish people, they will appreciate having a family name separated from their 'surname'.

Best bet is to define a data type for the name components, use those for a data type for the surname and tweak depending on locale.

AngularJS ui router passing data between states without URL

We can use params, new feature of the UI-Router:

API Reference / ui.router.state / $stateProvider

params A map which optionally configures parameters declared in the url, or defines additional non-url parameters. For each parameter being configured, add a configuration object keyed to the name of the parameter.

See the part: "...or defines additional non-url parameters..."

So the state def would be:

$stateProvider
  .state('home', {
    url: "/home",
    templateUrl: 'tpl.html',
    params: { hiddenOne: null, }
  })

Few examples form the doc mentioned above:

// define a parameter's default value
params: {
  param1: { value: "defaultValue" }
}
// shorthand default values
params: {
  param1: "defaultValue",
  param2: "param2Default"
}

// param will be array []
params: {
  param1: { array: true }
}

// handling the default value in url:
params: {
  param1: {
    value: "defaultId",
    squash: true
} }
// squash "defaultValue" to "~"
params: {
  param1: {
    value: "defaultValue",
    squash: "~"
  } }

EXTEND - working example: http://plnkr.co/edit/inFhDmP42AQyeUBmyIVl?p=info

Here is an example of a state definition:

 $stateProvider
  .state('home', {
      url: "/home",
      params : { veryLongParamHome: null, },
      ...
  })
  .state('parent', {
      url: "/parent",
      params : { veryLongParamParent: null, },
      ...
  })
  .state('parent.child', { 
      url: "/child",
      params : { veryLongParamChild: null, },
      ...
  })

This could be a call using ui-sref:

<a ui-sref="home({veryLongParamHome:'Home--f8d218ae-d998-4aa4-94ee-f27144a21238'
  })">home</a>

<a ui-sref="parent({ 
    veryLongParamParent:'Parent--2852f22c-dc85-41af-9064-d365bc4fc822'
  })">parent</a>

<a ui-sref="parent.child({
    veryLongParamParent:'Parent--0b2a585f-fcef-4462-b656-544e4575fca5',  
    veryLongParamChild:'Child--f8d218ae-d998-4aa4-94ee-f27144a61238'
  })">parent.child</a>

Check the example here

Woocommerce get products

Do not use WP_Query() or get_posts(). From the WooCommerce doc:

wc_get_products and WC_Product_Query provide a standard way of retrieving products that is safe to use and will not break due to database changes in future WooCommerce versions. Building custom WP_Queries or database queries is likely to break your code in future versions of WooCommerce as data moves towards custom tables for better performance.

You can retrieve the products you want like this:

$args = array(
    'category' => array( 'hoodies' ),
    'orderby'  => 'name',
);
$products = wc_get_products( $args );

WooCommerce documentation

Note: the category argument takes an array of slugs, not IDs.

How Exactly Does @param Work - Java

@param will not affect testNumber.It is a Javadoc comment - i.e used for generating documentation . You can put a Javadoc comment immediately before a class, field, method, constructor, or interface such as @param, @return . Generally begins with '@' and must be the first thing on the line.

The Advantage of using @param is :- By creating simple Java classes that contain attributes and some custom Javadoc tags, you allow those classes to serve as a simple metadata description for code generation.

    /* 
       *@param testNumber
       *@return integer
    */
    public int main testNumberIsValid(int testNumber){

       if (testNumber < 6) {
          //Something
        }
     }

Whenever in your code if you reuse testNumberIsValid method, IDE will show you the parameters the method accepts and return type of the method.

is the + operator less performant than StringBuffer.append()

Try this:

var s = ["<a href='", url, "'>click here</a>"].join("");

How to get a certain element in a list, given the position?

Maybe not the most efficient way. But you could convert the list into a vector.

#include <list>
#include <vector>

list<Object> myList;

vector<Object> myVector(myList.begin(), myList.end());

Then access the vector using the [x] operator.

auto x = MyVector[0];

You could put that in a helper function:

#include <memory>
#include <vector>
#include <list>

template<class T>
shared_ptr<vector<T>> 
ListToVector(list<T> List) {
shared_ptr<vector<T>> Vector {
        new vector<string>(List.begin(), List.end()) }
return Vector;
}

Then use the helper funciton like this:

auto MyVector = ListToVector(Object);
auto x = MyVector[0];

Remove a string from the beginning of a string

 
<?php
$str = 'bla_string_bla_bla_bla';
echo preg_replace('/bla_/', '', $str, 1); 
?>

Angular 5 - Copy to clipboard

As of Angular Material v9, it now has a clipboard CDK

Clipboard | Angular Material

It can be used as simply as 

<button [cdkCopyToClipboard]="This goes to Clipboard">Copy this</button>

Interface type check with Typescript

It's now possible, I just released an enhanced version of the TypeScript compiler that provides full reflection capabilities. You can instantiate classes from their metadata objects, retrieve metadata from class constructors and inspect interface/classes at runtime. You can check it out here

Usage example:

In one of your typescript files, create an interface and a class that implements it like the following:

interface MyInterface {
    doSomething(what: string): number;
}

class MyClass implements MyInterface {
    counter = 0;

    doSomething(what: string): number {
        console.log('Doing ' + what);
        return this.counter++;
    }
}

now let's print some the list of implemented interfaces.

for (let classInterface of MyClass.getClass().implements) {
    console.log('Implemented interface: ' + classInterface.name)
}

compile with reflec-ts and launch it:

$ node main.js
Implemented interface: MyInterface
Member name: counter - member kind: number
Member name: doSomething - member kind: function

See reflection.d.ts for Interface meta-type details.

UPDATE: You can find a full working example here

Visual Studio Code open tab in new window

If you are using the excellent

VSCode for Mac, 2020

simply tap Apple-Shift-N (as in "new window")

Drag whatever you want there.

setting y-axis limit in matplotlib

Just for fine tuning. If you want to set only one of the boundaries of the axis and let the other boundary unchanged, you can choose one or more of the following statements

plt.xlim(right=xmax) #xmax is your value
plt.xlim(left=xmin) #xmin is your value
plt.ylim(top=ymax) #ymax is your value
plt.ylim(bottom=ymin) #ymin is your value

Take a look at the documentation for xlim and for ylim

What are the Ruby File.open modes and options?

In Ruby IO module documentation, I suppose.

Mode |  Meaning
-----+--------------------------------------------------------
"r"  |  Read-only, starts at beginning of file  (default mode).
-----+--------------------------------------------------------
"r+" |  Read-write, starts at beginning of file.
-----+--------------------------------------------------------
"w"  |  Write-only, truncates existing file
     |  to zero length or creates a new file for writing.
-----+--------------------------------------------------------
"w+" |  Read-write, truncates existing file to zero length
     |  or creates a new file for reading and writing.
-----+--------------------------------------------------------
"a"  |  Write-only, starts at end of file if file exists,
     |  otherwise creates a new file for writing.
-----+--------------------------------------------------------
"a+" |  Read-write, starts at end of file if file exists,
     |  otherwise creates a new file for reading and
     |  writing.
-----+--------------------------------------------------------
"b"  |  Binary file mode (may appear with
     |  any of the key letters listed above).
     |  Suppresses EOL <-> CRLF conversion on Windows. And
     |  sets external encoding to ASCII-8BIT unless explicitly
     |  specified.
-----+--------------------------------------------------------
"t"  |  Text file mode (may appear with
     |  any of the key letters listed above except "b").

What is the &#xA; character?

It's the ASCII/UTF code for LF (0A) - Unix-based systems are using it as the newline character, while Windows uses the CR-LF PAIR (OD0A).

"Expected BEGIN_OBJECT but was STRING at line 1 column 1"

Don't use jsonObject.toString on a JSON object.

Has been compiled by a more recent version of the Java Runtime (class file version 57.0)

I have run into this issue When I recently upgraded my IntelliJ version to 2020.3. I had to disable a plugin to solve this issue. The name of the plugin is Thrift Support.

Steps to disable the plugin is following:

  1. Open the Preferences of IntelliJ. You can do so by clicking on Command + , in mac.
  2. Navigate to plugins.
  3. Search for the Thrift Support plugin in the search window. Click on the tick box icon to deselect it.
  4. Click on the Apply icon.
  5. See this image for reference Disable_Thrift_support_plugin

For more detail please refer to this link java.lang.UnsupportedClassVersionError 2020.3 version intellij. I found this comment in the above link which has worked for me.

bin zhao commented 31 Dec 2020 08:00 @Lejia Chen @Tobias Schulmann Workflow My IDEA3.X didn't installed Erlang plugin, I disabled Thrift Support 1.4.0 and it worked. Both IDEA 3.0 and 3.1 have the same problem.

Setting POST variable without using form

Yes, simply set it to another value:

$_POST['text'] = 'another value';

This will override the previous value corresponding to text key of the array. The $_POST is superglobal associative array and you can change the values like a normal PHP array.

Caution: This change is only visible within the same PHP execution scope. Once the execution is complete and the page has loaded, the $_POST array is cleared. A new form submission will generate a new $_POST array.

If you want to persist the value across form submissions, you will need to put it in the form as an input tag's value attribute or retrieve it from a data store.

How to Batch Rename Files in a macOS Terminal?

To rename files, you can use the rename utility:

brew install rename

For example, to change a search string in all filenames in current directory:

rename -nvs searchword replaceword *

Remove the 'n' parameter to apply the changes.

More info: man rename

How to fix a locale setting warning from Perl

 
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_ALL to default locale: No such file or directory

Solution:

Try this (uk_UA.UTF-8 is my current locale. Write your locale, for example en_US.UTF-8 !)

sudo locale-gen uk_UA.UTF-8

and this.

sudo dpkg-reconfigure locales

Installing jdk8 on ubuntu- "unable to locate package" update doesn't fix

I used another repository for oracle java.

sudo add-apt-repository ppa:linuxuprising/java
sudo apt-get update

sudo apt install  oracle-java11-installer

How to increase IDE memory limit in IntelliJ IDEA on Mac?

Helpful trick I thought I'd share on this old thread.

You can see how much memory is being used and adjust things accordingly using the Show memory indicator setting.

enter image description here

It shows up in the lower right of the window.

enter image description here

List names of all tables in a SQL Server 2012 schema

 
SELECT t.name 
  FROM sys.tables AS t
  INNER JOIN sys.schemas AS s
  ON t.[schema_id] = s.[schema_id]
  WHERE s.name = N'schema_name';

Change WPF controls from a non-main thread using Dispatcher.Invoke

The @japf answer above is working fine and in my case I wanted to change the mouse cursor from a Spinning Wheel back to the normal Arrow once the CEF Browser finished loading the page. In case it can help someone, here is the code:

private void Browser_LoadingStateChanged(object sender, CefSharp.LoadingStateChangedEventArgs e) {
   if (!e.IsLoading) {
      // set the cursor back to arrow
      Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background,
         new Action(() => Mouse.OverrideCursor = Cursors.Arrow));
   }
}

How to pass command line argument to gnuplot?

Yet another way is this:

You have a gnuplot script named scriptname.gp:

#!/usr/bin/gnuplot -p
# This code is in the file 'scriptname.gp'
EPATH = $0
FILENAME = $1 

plot FILENAME

Now you can call the gnuplot script scriptname.gp by this convoluted peace of syntax:

echo "call \"scriptname.gp\" \"'.'\" \"'data.dat'\"" | gnuplot

Playing HTML5 video on fullscreen in android webview

Tested on Android 9.0 version

None of the answers worked for me . This is the final thing worked 

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.FrameLayout;
import android.widget.ProgressBar;

public class MainActivity extends AppCompatActivity {

    WebView mWebView;


    @SuppressLint("SetJavaScriptEnabled")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        mWebView = (WebView) findViewById(R.id.webView);


        mWebView.setWebViewClient(new WebViewClient());
        mWebView.setWebChromeClient(new MyChrome());
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setAllowFileAccess(true);
        webSettings.setAppCacheEnabled(true);

       if (savedInstanceState == null) {
          mWebView.loadUrl("https://www.youtube.com/");
       }

    }


    private class MyChrome extends WebChromeClient {

        private View mCustomView;
        private WebChromeClient.CustomViewCallback mCustomViewCallback;
        protected FrameLayout mFullscreenContainer;
        private int mOriginalOrientation;
        private int mOriginalSystemUiVisibility;

        MyChrome() {}

        public Bitmap getDefaultVideoPoster()
        {
            if (mCustomView == null) {
                return null;
            }
            return BitmapFactory.decodeResource(getApplicationContext().getResources(), 2130837573);
        }

        public void onHideCustomView()
        {
            ((FrameLayout)getWindow().getDecorView()).removeView(this.mCustomView);
            this.mCustomView = null;
            getWindow().getDecorView().setSystemUiVisibility(this.mOriginalSystemUiVisibility);
            setRequestedOrientation(this.mOriginalOrientation);
            this.mCustomViewCallback.onCustomViewHidden();
            this.mCustomViewCallback = null;
        }

        public void onShowCustomView(View paramView, WebChromeClient.CustomViewCallback paramCustomViewCallback)
        {
            if (this.mCustomView != null)
            {
                onHideCustomView();
                return;
            }
            this.mCustomView = paramView;
            this.mOriginalSystemUiVisibility = getWindow().getDecorView().getSystemUiVisibility();
            this.mOriginalOrientation = getRequestedOrientation();
            this.mCustomViewCallback = paramCustomViewCallback;
            ((FrameLayout)getWindow().getDecorView()).addView(this.mCustomView, new FrameLayout.LayoutParams(-1, -1));
            getWindow().getDecorView().setSystemUiVisibility(3846 | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
        }
    }

 @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mWebView.saveState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        mWebView.restoreState(savedInstanceState);
    }
}

In AndroidManifest.xml

<activity
  android:name=".MainActivity"
  android:configChanges="orientation|screenSize" />

Source Monster Techno

How to install a .ipa file into my iPhone?

You need to install the provisioning profile (drag and drop it into iTunes). Then drag and drop the .ipa. Ensure you device is set to sync apps, and try again.

Get time difference between two dates in seconds

time difference between now and 10 minutes later using momentjs

let start_time = moment().format('YYYY-MM-DD HH:mm:ss');
let next_time = moment().add(10, 'm').format('YYYY-MM-DD HH:mm:ss');

let diff_milliseconds = Date.parse(next_time) - Date.parse(star_time);
let diff_seconds = diff_milliseconds * 1000;

Python function to convert seconds into minutes, hours, and days

Patching Mr.B's answer (sorry, not enough rep. to comment), we can return variable granularity based on the amount of time. For example, we don't say "1 week, 5 seconds", we just say "1 week":

def display_time(seconds, granularity=2):
    result = []

    for name, count in intervals:
        value = seconds // count
        if value:
            seconds -= value * count
            if value == 1:
                name = name.rstrip('s')
            result.append("{} {}".format(value, name))
        else:
            # Add a blank if we're in the middle of other values
            if len(result) > 0:
                result.append(None)
    return ', '.join([x for x in result[:granularity] if x is not None])

Some sample input:

for diff in [5, 67, 3600, 3605, 3667, 24*60*60, 24*60*60+5, 24*60*60+57, 24*60*60+3600, 24*60*60+3667, 2*24*60*60, 2*24*60*60+5*60*60, 7*24*60*60, 7*24*60*60 + 24*60*60]:
    print "For %d seconds: %s" % (diff, display_time(diff, 2))

...returns this output:

For 5 seconds: 5 seconds
For 67 seconds: 1 minute, 7 seconds
For 3600 seconds: 1 hour
For 3605 seconds: 1 hour
For 3667 seconds: 1 hour, 1 minute
For 86400 seconds: 1 day
For 86405 seconds: 1 day
For 86457 seconds: 1 day
For 90000 seconds: 1 day, 1 hour
For 90067 seconds: 1 day, 1 hour
For 172800 seconds: 2 days
For 190800 seconds: 2 days, 5 hours
For 604800 seconds: 1 week
For 691200 seconds: 1 week, 1 day

How to get relative path of a file in visual studio?

In Visual Studio please click 'Folder.ico' file in the Solution Explorer pane. Then you will see Properties pane. Change 'Copy to Output Directory' behavior to 'Copy if newer'. This will make Visual Studio copy the file to the output bin directory.

Now to get the file path using relative path just type:

string pathToIcoFile = AppDomain.CurrentDomain.BaseDirectory + "//FolderIcon//Folder.ico";

Hope that helped.

Including .cpp files

There are many reasons to discourage including a .cpp file, but it isn't strictly disallowed. Your example should compile fine.

The problem is probably that you're compiling both main.cpp and foop.cpp, which means two copies of foop.cpp are being linked together. The linker is complaining about the duplication.

Postgres FOR LOOP

Procedural elements like loops are not part of the SQL language and can only be used inside the body of a procedural language function, procedure (Postgres 11 or later) or a DO statement, where such additional elements are defined by the respective procedural language. The default is PL/pgSQL, but there are others.

Example with plpgsql:

DO
$do$
BEGIN 
   FOR i IN 1..25 LOOP
      INSERT INTO playtime.meta_random_sample
         (col_i, col_id)                       -- declare target columns!
      SELECT  i,     id
      FROM   tbl
      ORDER  BY random()
      LIMIT  15000;
   END LOOP;
END
$do$;

For many tasks that can be solved with a loop, there is a shorter and faster set-based solution around the corner. Pure SQL equivalent for your example:

INSERT INTO playtime.meta_random_sample (col_i, col_id)
SELECT t.*
FROM   generate_series(1,25) i
CROSS  JOIN LATERAL (
   SELECT i, id
   FROM   tbl
   ORDER  BY random()
   LIMIT  15000
   ) t;

About generate_series():

About optimizing performance of random selections:

How to replace multiple white spaces with one white space

VB.NET

Linha.Split(" ").ToList().Where(Function(x) x <> " ").ToArray

C#

Linha.Split(" ").ToList().Where(x => x != " ").ToArray();

Enjoy the power of LINQ =D

What is the current choice for doing RPC in Python?

XML-RPC is part of the Python standard library:

python: how to send mail with TO, CC and BCC?

It did not worked for me until i created:

#created cc string
cc = ""[email protected];
#added cc to header
msg['Cc'] = cc

and than added cc in recipient [list] like:

s.sendmail(me, [you,cc], msg.as_string())

MySQL - how to front pad zip code with "0"?

Ok, so you've switched the column from Number to VARCHAR(5). Now you need to update the zipcode field to be left-padded. The SQL to do that would be:

UPDATE MyTable
SET ZipCode = LPAD( ZipCode, 5, '0' );

This will pad all values in the ZipCode column to 5 characters, adding '0's on the left.

Of course, now that you've got all of your old data fixed, you need to make sure that your any new data is also zero-padded. There are several schools of thought on the correct way to do that:

  • Handle it in the application's business logic. Advantages: database-independent solution, doesn't involve learning more about the database. Disadvantages: needs to be handled everywhere that writes to the database, in all applications.

  • Handle it with a stored procedure. Advantages: Stored procedures enforce business rules for all clients. Disadvantages: Stored procedures are more complicated than simple INSERT/UPDATE statements, and not as portable across databases. A bare INSERT/UPDATE can still insert non-zero-padded data.

  • Handle it with a trigger. Advantages: Will work for Stored Procedures and bare INSERT/UPDATE statements. Disadvantages: Least portable solution. Slowest solution. Triggers can be hard to get right.

In this case, I would handle it at the application level (if at all), and not the database level. After all, not all countries use a 5-digit Zipcode (not even the US -- our zipcodes are actually Zip+4+2: nnnnn-nnnn-nn) and some allow letters as well as digits. Better NOT to try and force a data format and to accept the occasional data error, than to prevent someone from entering the correct value, even though it's format isn't quite what you expected.

INNER JOIN in UPDATE sql for DB2

Joins in update statements are non-standard and not supported by all vendors. What you're trying to do can be accomplished with a sub-select:

update
  file1
set
  firstfield = (select 'stuff' concat something from file2 where substr(file1.field1, 10, 20) = substr(file2.xxx,1,10) )
where
  file1.foo like 'BLAH%'

How do I determine if my python shell is executing in 32bit or 64bit?

Grouping everything...

Considering that:

  • The question is asked for OSX (I have an old (and cracked) VM with an ancient Python version)
  • My main env is Win
  • I only have the 32bit version installed on Win (and I built a "crippled" one on Lnx)

I'm going to exemplify on all 3 platforms, using Python 3 and Python 2.

  1. Check [Python 3.Docs]: sys.maxsize value - compare it to 0x100000000 (2 ** 32): greater for 64bit, smaller for 32bit:
    • OSX 9 x64:
      • Python 2.7.10 x64: 
        >>> import sys
>>> "Python {0:s} on {1:s}".format(sys.version, sys.platform)
'Python 2.7.10 (default, Oct 14 2015, 05:51:29) \n[GCC 4.8.2] on darwin'
>>> hex(sys.maxsize), sys.maxsize > 0x100000000
('0x7fffffffffffffff', True)
    • Ubuntu 16 x64:
      • Python 3.5.2 x64: 
        >>> import sys
>>> "Python {0:s} on {1:s}".format(sys.version, sys.platform)
'Python 3.5.2 (default, Nov 23 2017, 16:37:01) \n[GCC 5.4.0 20160609] on linux'
>>> hex(sys.maxsize), sys.maxsize > 0x100000000
('0x7fffffffffffffff', True)
      • Python 3.6.4 x86: 
        >>> import sys
>>> "Python {0:s} on {1:s}".format(sys.version, sys.platform)
'Python 3.6.4 (default, Apr 25 2018, 23:55:56) \n[GCC 5.4.0 20160609] on linux'
>>> hex(sys.maxsize), sys.maxsize > 0x100000000
('0x7fffffff', False)
    • Win 10 x64:
      • Python 3.5.4 x64: 
        >>> import sys
>>> "Python {0:s} on {1:s}".format(sys.version, sys.platform)
'Python 3.5.4 (v3.5.4:3f56838, Aug  8 2017, 02:17:05) [MSC v.1900 64 bit (AMD64)] on win32'
>>> hex(sys.maxsize), sys.maxsize > 0x100000000
('0x7fffffffffffffff', True)
      • Python 3.6.2 x86: 
        >>> import sys
>>> "Python {0:s} on {1:s}".format(sys.version, sys.platform)
'Python 3.6.2 (v3.6.2:5fd33b5, Jul  8 2017, 04:14:34) [MSC v.1900 32 bit (Intel)] on win32'
>>> hex(sys.maxsize), sys.maxsize > 0x100000000
('0x7fffffff', False)


  1. Use [Python 3.Docs]: struct.calcsize(format) to determine the object size produced by the (pointer) format. In other words, determines the pointer size (sizeof(void*)):
    • OSX 9 x64:
      • Python 2.7.10 x64: 
        >>> import struct
>>> struct.calcsize("P") * 8
64
    • Ubuntu 16 x64:
      • Python 3.5.2 x64: 
        >>> import struct
>>> struct.calcsize("P") * 8
64
      • Python 3.6.4 x86: 
        >>> import struct
>>> struct.calcsize("P") * 8
32
    • Win 10 x64:
      • Python 3.5.4 x64: 
        >>> import struct
>>> struct.calcsize("P") * 8
64
      • Python 3.6.2 x86: 
        >>> import struct
>>> struct.calcsize("P") * 8
32


  1. Use [Python 3.Docs]: ctypes - A foreign function library for Python. It also boils down to determining the size of a pointer (sizeof(void*)). As a note, ctypes uses #2. (not necessarily for this task) via "${PYTHON_SRC_DIR}/Lib/ctypes/__init__.py" (around line #15):
    • OSX 9 x64:
      • Python 2.7.10 x64: 
        >>> import ctypes
>>> ctypes.sizeof(ctypes.c_void_p) * 8
64
    • Ubuntu 16 x64:
      • Python 3.5.2 x64: 
        >>> import ctypes
>>> ctypes.sizeof(ctypes.c_void_p) * 8
64
      • Python 3.6.4 x86: 
        >>> import ctypes
>>> ctypes.sizeof(ctypes.c_void_p) * 8
32
    • Win 10 x64:
      • Python 3.5.4 x64: 
        >>> import ctypes
>>> ctypes.sizeof(ctypes.c_void_p) * 8
64
      • Python 3.6.2 x86: 
        >>> import ctypes
>>> ctypes.sizeof(ctypes.c_void_p) * 8
32


  1. [Python 3.Docs]: platform.architecture(executable=sys.executable, bits='', linkage='') !!! NOT reliable on OSX !!! due to multi arch executable (or .dylib) format (in some cases, uses #2.):
    • OSX 9 x64:
      • Python 2.7.10 x64: 
        >>> import platform
>>> platform.architecture()
('64bit', '')
    • Ubuntu 16 x64:
      • Python 3.5.2 x64: 
        >>> import platform
>>> platform.architecture()
('64bit', 'ELF')
      • Python 3.6.4 x86: 
        >>> import platform
>>> platform.architecture()
('32bit', 'ELF')
    • Win 10 x64:
      • Python 3.5.4 x64: 
        >>> import platform
>>> platform.architecture()
('64bit', 'WindowsPE')
      • Python 3.6.2 x86: 
        >>> import platform
>>> platform.architecture()
('32bit', 'WindowsPE')


  1. Lame workaround (gainarie) - invoke an external command ([man7]: FILE(1)) via [Python 3.Docs]: os.system(command). The limitations of #4. apply (sometimes it might not even work):
    • OSX 9 x64:
      • Python 2.7.10 x64: 
        >>> import os
>>> os.system("file {0:s}".format(os.path.realpath(sys.executable)))
/opt/OPSWbuildtools/2.0.6/bin/python2.7.global: Mach-O 64-bit executable x86_64
    • Ubuntu 16 x64:
      • Python 3.5.2 x64: 
        >>> import os
>>> os.system("file {0:s}".format(os.path.realpath(sys.executable)))
/usr/bin/python3.5: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=59a8ef36ca241df24686952480966d7bc0d7c6ea, stripped
      • Python 3.6.4 x86: 
        >>> import os
>>> os.system("file {0:s}".format(os.path.realpath(sys.executable)))
/home/cfati/Work/Dev/Python-3.6.4/python: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=5c3d4eeadbd13cd91445d08f90722767b0747de2, not stripped
    • Win 10 x64:
      • file utility is not present, there are other 3rd Party tools that can be used, but I'm not going to insist on them


Win specific:

  1. Check env vars (e.g. %PROCESSOR_ARCHITECTURE% (or others)) via [Python 3.Docs]: os.environ:
    • Win 10 x64:
      • Python 3.5.4 x64: 
        >>> import os
>>> os.environ["PROCESSOR_ARCHITECTURE"]
'AMD64'
      • Python 3.6.2 x86: 
        >>> import os
>>> os.environ["PROCESSOR_ARCHITECTURE"]
'x86'


  1. [Python 3.Docs]: sys.version (also displayed in the 1st line when starting the interpreter)
    • Check #1.

How do you use math.random to generate random ints?

you are importing java.util package. That's why its giving error. there is a random() in java.util package too. Please remove the import statement importing java.util package. then your program will use random() method for java.lang by default and then your program will work. remember to cast it i.e

int x = (int)(Math.random()*100);

Why can't DateTime.Parse parse UTC date

Just replace "UTC" with "GMT" -- simple and doesn't break correctly formatted dates:

DateTime.Parse("Tue, 1 Jan 2008 00:00:00 UTC".Replace("UTC", "GMT"))

Get started with Latex on Linux

LaTeX comes with most Linux distributions in the form of the teTeX distribution. Find all packages with 'teTeX' in the name and install them.

  • Most editors such as vim or emacs come with TeX editing modes. You can also get WYSIWIG-ish front-ends (technically WYSIWYM), of which perhaps the best known is LyX.

  • The best quick intro to LaTeX is Oetiker's 'The not so short intro to LaTeX'

  • LaTeX works like a compiler. You compile the LaTeX document (which can include other files), which generates a file called a .dvi (device independent). This can be post-processed to various formats (including PDF) with various post-processors.

  • To do PDF, use dvips and use the flag -PPDF (IIRC - I don't have a makefile to hand) to produce a PS with font rendering set up for conversion to pdf. PDF conversion can then be done with ps2pdf or distiller (if you have this).

  • The best format for including graphics in this environment is eps (Encapsulated Postscript) although not all software produces well-behaved postscript. Photographs in jpeg or other formats can be included using various mechanisms.

React setState not updating state

The setState() operation is asynchronous and hence your console.log() will be executed before the setState() mutates the values and hence you see the result.

To solve it, log the value in the callback function of setState(), like:

setTimeout(() => {
    this.setState({dealersOverallTotal: total},
    function(){
       console.log(this.state.dealersOverallTotal, 'dealersOverallTotal1');
    });
}, 10)

How to find if element with specific id exists or not

You need to specify which object you're calling getElementById from. In this case you can use document. You also can't just call .value on any element directly. For example if the element is textbox .value will return the value, but if it's a div it will not have a value.

You also have a wrong condition, you're checking

if (myEle == null)

which you should change to

if (myEle != null)

var myEle = document.getElementById("myElement");
if(myEle != null) { 
    var myEleValue= myEle.value; 
}

HTML Table different number of columns in different rows

If you need different column width, do this:

<tr>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
    <td></td>
</tr>
<tr>
    <td colspan="9">
        <table>
            <tr>
                <td></td>
                <td></td>
                <td></td>
                <td></td>
            </tr>
        </table>
    </td>
</tr>

How can I center <ul> <li> into div

Interesting but try this with floated li elements inside the ul: Example here

The problem now: the ul needs a fixed width to actually sit in the center. However we want to be it relative to the container width (or dynamic), margin: 0 auto on the ul does not work.

A better way is to let go of UL/Li list and use a different approach example here

Python equivalent of D3.js

I've got a good example of automatically generating D3.js network diagrams using Python here: http://brandonrose.org/ner2sna

The cool thing is that you end up with auto-generated HTML and JS and can embed the interactive D3 chart in a notebook with an IFrame

Nginx: Job for nginx.service failed because the control process exited

  • use these command to

    1. sudo service apache2 stop

    2. sudo apt-get purge apache2

    3. sudo apt-get update

    4. sudo apt-get install nginx

    5. sudo service nginx restart

What does "commercial use" exactly mean?

Fundamentally if you use it as part of a business then its commercial use - so its not a matter of whether the tools are directly generating income or not rather one of if they are being used in support of income generation directly or indirectly.

To take your specific example, if the purpose of the site is to sell or promote your paid services/product then its a commercial enterprise.

How to break out of a loop in Bash?

It's not that different in bash.

workdone=0
while : ; do
  ...
  if [ "$workdone" -ne 0 ]; then
      break
  fi
done

: is the no-op command; its exit status is always 0, so the loop runs until workdone is given a non-zero value.

There are many ways you could set and test the value of workdone in order to exit the loop; the one I show above should work in any POSIX-compatible shell.

Django - how to create a file and save it to a model's FileField?

Accepted answer is certainly a good solution, but here is the way I went about generating a CSV and serving it from a view.

Thought it was worth while putting this here as it took me a little bit of fiddling to get all the desirable behaviour (overwrite existing file, storing to the right spot, not creating duplicate files etc).

Django 1.4.1

Python 2.7.3

#Model
class MonthEnd(models.Model):
    report = models.FileField(db_index=True, upload_to='not_used')

import csv
from os.path import join

#build and store the file
def write_csv():
    path = join(settings.MEDIA_ROOT, 'files', 'month_end', 'report.csv')
    f = open(path, "w+b")

    #wipe the existing content
    f.truncate()

    csv_writer = csv.writer(f)
    csv_writer.writerow(('col1'))

    for num in range(3):
        csv_writer.writerow((num, ))

    month_end_file = MonthEnd()
    month_end_file.report.name = path
    month_end_file.save()

from my_app.models import MonthEnd

#serve it up as a download
def get_report(request):
    month_end = MonthEnd.objects.get(file_criteria=criteria)

    response = HttpResponse(month_end.report, content_type='text/plain')
    response['Content-Disposition'] = 'attachment; filename=report.csv'

    return response

How to sort a dataFrame in python pandas by two or more columns?

As of pandas 0.17.0, DataFrame.sort() is deprecated, and set to be removed in a future version of pandas. The way to sort a dataframe by its values is now is DataFrame.sort_values

As such, the answer to your question would now be

df.sort_values(['b', 'c'], ascending=[True, False], inplace=True)

Ruby objects and JSON serialization (without Rails)

Jbuilder is a gem built by rails community. But it works well in non-rails environments and have a cool set of features.

# suppose we have a sample object as below
sampleObj.name #=> foo
sampleObj.last_name #=> bar

# using jbuilder we can convert it to json:
Jbuilder.encode do |json|
  json.name sampleObj.name
  json.last_name sampleObj.last_name
end #=> "{:\"name\" => \"foo\", :\"last_name\" => \"bar\"}"

How to fire AJAX request Periodically?

As others have pointed out setInterval and setTimeout will do the trick. I wanted to highlight a bit more advanced technique that I learned from this excellent video by Paul Irish: http://paulirish.com/2010/10-things-i-learned-from-the-jquery-source/

For periodic tasks that might end up taking longer than the repeat interval (like an HTTP request on a slow connection) it's best not to use setInterval(). If the first request hasn't completed and you start another one, you could end up in a situation where you have multiple requests that consume shared resources and starve each other. You can avoid this problem by waiting to schedule the next request until the last one has completed:

// Use a named immediately-invoked function expression.
(function worker() {
  $.get('ajax/test.html', function(data) {
    // Now that we've completed the request schedule the next one.
    $('.result').html(data);
    setTimeout(worker, 5000);
  });
})();

For simplicity I used the success callback for scheduling. The down side of this is one failed request will stop updates. To avoid this you could use the complete callback instead:

(function worker() {
  $.ajax({
    url: 'ajax/test.html', 
    success: function(data) {
      $('.result').html(data);
    },
    complete: function() {
      // Schedule the next request when the current one's complete
      setTimeout(worker, 5000);
    }
  });
})();

Differences between key, superkey, minimal superkey, candidate key and primary key

I have always found it difficult to remember all the keys; so I keep the below notes handy, hope they help someone! Let me know if it can be improved.

  • Key: An attribute or combination of attributes that uniquely identify an entity/record in a relational table.

  • PK: A single key that is unique and not-null. It is one of the candidate keys.

  • Foreign Key: FK is a key in one table (child) that uniquely identifies a row of another table (parent). A FK is not-unique in the child table. It is a candidate key in the parent table. Referential integrity is maintained as the value in FK is present as a value in PK in parent table else it is NULL.

  • Unique Key: A unique key that may or may not be NULL

  • Natural key: PK in OLTP. It may be a PK in OLAP.

  • Surrogate Key: It is the Surrogate PK in OLAP acting as the substitute of the PK in OLTP. Artificial key generated internally in OLAP.

  • Composite Key: PK made up of multiple attributes

  • SuperKey: A key that can be uniquely used to identify a database record, that may contain extra attributes that are not necessary to uniquely identify records.

  • Candidate Key: A candidate key can be uniquely used to identify a database record without any extraneous data. They are Not Null and unique. It is a minimal super-key.

  • Alternate Key: A candidate key that is not the primary key is called an alternate key.

  • Candidate Key/s with Extraneous data: Consider that can be used to identify a record in the Employee table but candidate key alone is sufficient for this task. So becomes the extraneous data.

Note that the PK, Foreign Key, Unique Key, Natural key, Surrogate Key, Composite Key are defined as Database objects; where the Natural key is a PK in the OLTP and could be a PK in the target OLAP. For the rest of the keys, it's up to the DB designer/architect to decide whether unique/not-null/referential integrity constraints need to enforced or not.

Below I have tried to use set theory to simplify the representation of the membership of the keys w.r.t. each other.

key = { All of the below keys   }
PK  = { PK  }
Foreign Key = { Key with Not Null constraint    }
Unique Key  = { {Candidate Key/s}, {attributes containing NULL} }
Natural key = { PK  }
Surrogate Key   = { PK  }
Composite Key   = { PK  }
Super Key   = { {Candidate Key/s}, {Candidate Key/s with Extraneous data}   }
Candidate Key   = { PK, {Alternate Key/s}   }
Alternate Key   = { {Candidate Keys} - PK   }
Candidate Key/s with Extraneous data    = {     }

I have summarized it below:

Database Keys

Notes: an-overview-of-the-database-keys-primary-key-composite-key-surrogate-key-et-al

What is the "proper" way to cast Hibernate Query.list() to List<Type>?

The resolution is to use TypedQuery instead. When creating a query from the EntityManager instead call it like this: 

TypedQuery<[YourClass]> query = entityManager.createQuery("[your sql]", [YourClass].class);
List<[YourClass]> list = query.getResultList(); //no type warning

This also works the same for named queries, native named queries, etc. The corresponding methods have the same names as the ones that would return the vanilla query. Just use this instead of a Query whenever you know the return type.

Can't bind to 'formControl' since it isn't a known property of 'input' - Angular2 Material Autocomplete issue

Forget trying to decipher the example .ts - as others have said it is often incomplete.

Instead just click on the 'pop-out' icon circled here and you'll get a fully working StackBlitz example.

enter image description here

You can quickly confirm the required modules:

enter image description here

Comment out any instances of ReactiveFormsModule, and sure enough you'll get the error:

Template parse errors:
Can't bind to 'formControl' since it isn't a known property of 'input'.

How can I test a PDF document if it is PDF/A compliant?

If you download the latest version of Adobe Acrobat Reader, it will tell you if your pdf is PDF/A compliant. Just open the PDF file and a big blue marking should appear.

OpenOffice supports PDF/A. For some reason "PDF/A-1" is called 

"SelectPdfVersion"
internally in OpenOffice. Just add 1 to that value and your output should be PDF/A.

The different values can be

0 = PDFXNONE
1 = PDFX1A2001
2 = PDFX32002
3 = PDFA1A
4 = PDFA1B

You set 

FilterData
to be a 
HashMap('SelectPdfVersion',1) //1 for PDFX1A2001

Reset all the items in a form

 
foreach (Control field in container.Controls)
            {
                if (field is TextBox)
                    ((TextBox)field).Clear();
                else if (field is ComboBox)
                    ((ComboBox)field).SelectedIndex=0;
                else
                    dgView.DataSource = null;
                    ClearAllText(field);
            }

Are arrays in PHP copied as value or as reference to new variables, and when passed to functions?

By default

  1. Primitives are passed by value. Unlikely to Java, string is primitive in PHP
  2. Arrays of primitives are passed by value
  3. Objects are passed by reference

  4. Arrays of objects are passed by value (the array) but each object is passed by reference.

    <?php
$obj=new stdClass();
$obj->field='world';

$original=array($obj);


function example($hello) {
    $hello[0]->field='mundo'; // change will be applied in $original
    $hello[1]=new stdClass(); // change will not be applied in $original
    $
}

example($original);

var_dump($original);
// array(1) { [0]=> object(stdClass)#1 (1) { ["field"]=> string(5) "mundo" } }

Note: As an optimization, every single value is passed as reference until its modified inside the function. If it's modified and the value was passed by reference then, it's copied and the copy is modified.

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12:test (default-test) on project.

I was facing the same kind of issue, your version numbers in the dependency of Selenium, TestNG, Junit should the same that you have used in your project. For example, in your project you are using the Selenium version 3.8. This version number should be mentioned in the dependency.

 <dependency>
    <groupId>org.testng</groupId>
    <artifactId>testng</artifactId>
    <version>7.0.0-beta1</version>
    <scope>test</scope>
</dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.seleniumhq.selenium</groupId>
      <artifactId>selenium-java</artifactId>
      <version>3.8.1</version>
    </dependency>       
    <dependency>                
      <groupId>org.testng</groupId>                             
      <artifactId>testng</artifactId>                               
      <version>6.8</version>                                
      <scope>test</scope>                                       
    </dependency>   
  </dependencies>

How to get a barplot with several variables side by side grouped by a factor

You can plot the means without resorting to external calculations and additional tables using stat_summary(...). In fact, stat_summary(...) was designed for exactly what you are doing.

library(ggplot2)
library(reshape2)            # for melt(...)
gg <- melt(df,id="gender")   # df is your original table
ggplot(gg, aes(x=variable, y=value, fill=factor(gender))) + 
  stat_summary(fun.y=mean, geom="bar",position=position_dodge(1)) + 
  scale_color_discrete("Gender")
  stat_summary(fun.ymin=min,fun.ymax=max,geom="errorbar",
               color="grey80",position=position_dodge(1), width=.2)

To add "error bars" you cna also use stat_summary(...) (here, I'm using the min and max value rather than sd because you have so little data).

ggplot(gg, aes(x=variable, y=value, fill=factor(gender))) + 
  stat_summary(fun.y=mean, geom="bar",position=position_dodge(1)) + 
  stat_summary(fun.ymin=min,fun.ymax=max,geom="errorbar",
               color="grey40",position=position_dodge(1), width=.2) +
  scale_fill_discrete("Gender")

Eclipse - no Java (JRE) / (JDK) ... no virtual machine

Solution in a nutshell:

Right-click on My Computer, click properties, then advanced system settings, a System properties window will popup, under advanced tab, choose environment variables, Environment variables window will popup, under the System variables section , look for PATH variable, and edit the value, changing it (the version; jre6,jre7, etc) to whatever jre you're using, e.g for mine: C:\Program Files\Java\jre7\bin

How to bind list to dataGridView?

Use a BindingList and set the DataPropertyName-Property of the column.

Try the following:

...
private void BindGrid()
{
    gvFilesOnServer.AutoGenerateColumns = false;

    //create the column programatically
    DataGridViewCell cell = new DataGridViewTextBoxCell();
    DataGridViewTextBoxColumn colFileName = new DataGridViewTextBoxColumn()
    {
        CellTemplate = cell, 
        Name = "Value",
        HeaderText = "File Name",
        DataPropertyName = "Value" // Tell the column which property of FileName it should use
     };

    gvFilesOnServer.Columns.Add(colFileName);

    var filelist = GetFileListOnWebServer().ToList();
    var filenamesList = new BindingList<FileName>(filelist); // <-- BindingList

    //Bind BindingList directly to the DataGrid, no need of BindingSource
    gvFilesOnServer.DataSource = filenamesList 
}

Conditional Replace Pandas

.ix indexer works okay for pandas version prior to 0.20.0, but since pandas 0.20.0, the .ix indexer is deprecated, so you should avoid using it. Instead, you can use .loc or iloc indexers. You can solve this problem by:

mask = df.my_channel > 20000
column_name = 'my_channel'
df.loc[mask, column_name] = 0

Or, in one line,

df.loc[df.my_channel > 20000, 'my_channel'] = 0

mask helps you to select the rows in which df.my_channel > 20000 is True, while df.loc[mask, column_name] = 0 sets the value 0 to the selected rows where maskholds in the column which name is column_name.

Update: In this case, you should use loc because if you use iloc, you will get a NotImplementedError telling you that iLocation based boolean indexing on an integer type is not available.

How to POST request using RestSharp

As of 2017 I post to a rest service and getting the results from it like that:

        var loginModel = new LoginModel();
        loginModel.DatabaseName = "TestDB";
        loginModel.UserGroupCode = "G1";
        loginModel.UserName = "test1";
        loginModel.Password = "123";

        var client = new RestClient(BaseUrl);

        var request = new RestRequest("/Connect?", Method.POST);
        request.RequestFormat = DataFormat.Json;
        request.AddBody(loginModel);

        var response = client.Execute(request);

        var obj = JObject.Parse(response.Content);

        LoginResult result = new LoginResult
        {
            Status = obj["Status"].ToString(),
            Authority = response.ResponseUri.Authority,
            SessionID = obj["SessionID"].ToString()
        };

Show Youtube video source into HTML5 video tag?

how about doing it the way hooktube does it? they don't actually use the video URL for the html5 element, but the google video redirector url that calls upon that video. check out here's how they present some despacito random video...

<video id="player-obj" controls="" src="https://redirector.googlevideo.com/videoplayback?ratebypass=yes&amp;mt=1510077993----SKIPPED----amp;utmg=ytap1,,hd720"><source>Your browser does not support HTML5 video.</video>

the code is for the following video page https://hooktube.com/watch?v=72UO0v5ESUo

youtube to mp3 on the other hand has turned into extremely monetized monster that returns now download.html on half of video download requests... annoying...

the 2 links in this answer are to my personal experiences with both resources. how hooktube is nice and fresh and actually helps avoid censorship and geo restrictions.. check it out, it's pretty cool. and youtubeinmp4 is a popup monster now known as ConvertInMp4...

Reset the database (purge all), then seed a database

If you don't feel like dropping and recreating the whole shebang just to reload your data, you could use MyModel.destroy_all (or delete_all) in the seed.db file to clean out a table before your MyModel.create!(...) statements load the data. Then, you can redo the db:seed operation over and over. (Obviously, this only affects the tables you've loaded data into, not the rest of them.)

There's a "dirty hack" at https://stackoverflow.com/a/14957893/4553442 to add a "de-seeding" operation similar to migrating up and down...

Table with table-layout: fixed; and how to make one column wider

You could just give the first cell (therefore column) a width and have the rest default to auto

_x000D_
_x000D_ 
table {_x000D_
  table-layout: fixed;_x000D_
  border-collapse: collapse;_x000D_
  width: 100%;_x000D_
}_x000D_
td {_x000D_
  border: 1px solid #000;_x000D_
  width: 150px;_x000D_
}_x000D_
td+td {_x000D_
  width: auto;_x000D_
}
_x000D_ 
<table>_x000D_
  <tr>_x000D_
    <td>150px</td>_x000D_
    <td>equal</td>_x000D_
    <td>equal</td>_x000D_
  </tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_

or alternatively the "proper way" to get column widths might be to use the col element itself

_x000D_
_x000D_ 
table {_x000D_
  table-layout: fixed;_x000D_
  border-collapse: collapse;_x000D_
  width: 100%;_x000D_
}_x000D_
td {_x000D_
  border: 1px solid #000;_x000D_
}_x000D_
.wide {_x000D_
  width: 150px;_x000D_
}
_x000D_ 
<table>_x000D_
  <col span="1" class="wide">_x000D_
    <tr>_x000D_
      <td>150px</td>_x000D_
      <td>equal</td>_x000D_
      <td>equal</td>_x000D_
    </tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_

How do I find out my root MySQL password?

Here is the best way to set your root password : Source Link Step 3 is working perfectly for me.

Commands for You

  1. sudo mysql
  2. SELECT user,authentication_string,plugin,host FROM mysql.user;
  3. ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
  4. FLUSH PRIVILEGES;
  5. SELECT user,authentication_string,plugin,host FROM mysql.user;
  6. exit

Now you can use the Password for the root user is 'password' :

  1. mysql -u root -p
  2. CREATE USER 'sammy'@'localhost' IDENTIFIED BY 'password';
  3. GRANT ALL PRIVILEGES ON . TO 'sammy'@'localhost' WITH GRANT OPTION;
  4. FLUSH PRIVILEGES;
  5. exit

Test your MySQL Service and Version:

systemctl status mysql.service
sudo mysqladmin -p -u root version

Why do people say that Ruby is slow?

People say that Ruby is slow because they compare Ruby programs to programs written in other languages. Maybe the programs you write don't need to be faster. Maybe for the programs you write Ruby isn't the bottleneck that's slowing things down.

Ruby 2.1 compared to Javascript V8

Ruby 2.1 compared to ordinary Lua

Ruby 2.1 compared to Python 3

How to upgrade Git to latest version on macOS?

I prefer not to alter the path hierarchy, but instead deal with git specifically...knowing that I'm never going to use old git to do what new git will now manage. This is a brute force solution.

NOTE: I installed XCode on Yosemite (10.10.2) clean first.

I then installed from the binary available on git-scm.com. 

$ which git
/usr/bin/git
$ cd /usr/bin
$ sudo ln -sf /usr/local/git/bin/git
$ sudo ln -sf /usr/local/git/bin/git-credential-osxkeychain
$ sudo ln -sf /usr/local/git/bin/git-cvsserver
$ sudo ln -sf /usr/local/git/bin/git-receive-pack
$ sudo ln -sf /usr/local/git/bin/git-shell
$ sudo ln -sf /usr/local/git/bin/git-upload-archive
$ sudo ln -sf /usr/local/git/bin/git-upload-pack
$ ls -la
(you should see your new symlinks)

sql how to cast a select query

Yes you can do.

Syntax for CAST: 

CAST ( expression AS data_type [ ( length ) ] )

For example:

CAST(MyColumn AS Varchar(10))

CAST in SELECT Statement:

Select CAST(MyColumn AS Varchar(10)) AS MyColumn
FROM MyTable

See for more information CAST and CONVERT (Transact-SQL)

IntelliJ inspection gives "Cannot resolve symbol" but still compiles code

mvn idea:idea worked for me. Found it here. Spent more than an hour, hope it helps someone

How do I access call log for android?

Before considering making Read Call Log or Read SMS permissions a part of your application I strongly advise you to have a look at this policy of Google Play Market: https://support.google.com/googleplay/android-developer/answer/9047303?hl=en

Those permissions are very sensitive and you will have to prove that your application needs them. But even if it really needs them Google Play Support team may easily reject your request without proper explanations.

This is what happened to me. After providing all the needed information along with the Demonstration video of my application it was rejected with the explanation that my "account is not authorized to provide a certain use case solution in my application" (the list of use cases they may consider as an exception is listed on that Policy page). No link to any policy statement was provided to explain what it all means. Basically they just judged my app as not to go without proper explanation.

I wish you good luck of cause with your applications guys but be careful.

java.lang.NoClassDefFoundError: org.slf4j.LoggerFactory

this worked for me /properties/maven uncheck resolve dependencies from Workspace projects.

Find and replace string values in list

In case you're wondering about the performance of the different approaches, here are some timings:

In [1]: words = [str(i) for i in range(10000)]

In [2]: %timeit replaced = [w.replace('1', '<1>') for w in words]
100 loops, best of 3: 2.98 ms per loop

In [3]: %timeit replaced = map(lambda x: str.replace(x, '1', '<1>'), words)
100 loops, best of 3: 5.09 ms per loop

In [4]: %timeit replaced = map(lambda x: x.replace('1', '<1>'), words)
100 loops, best of 3: 4.39 ms per loop

In [5]: import re

In [6]: r = re.compile('1')

In [7]: %timeit replaced = [r.sub('<1>', w) for w in words]
100 loops, best of 3: 6.15 ms per loop

as you can see for such simple patterns the accepted list comprehension is the fastest, but look at the following:

In [8]: %timeit replaced = [w.replace('1', '<1>').replace('324', '<324>').replace('567', '<567>') for w in words]
100 loops, best of 3: 8.25 ms per loop

In [9]: r = re.compile('(1|324|567)')

In [10]: %timeit replaced = [r.sub('<\1>', w) for w in words]
100 loops, best of 3: 7.87 ms per loop

This shows that for more complicated substitutions a pre-compiled reg-exp (as in 9-10) can be (much) faster. It really depends on your problem and the shortest part of the reg-exp.

"’" showing on page instead of " ' "

If your content type is already UTF8 , then it is likely the data is already arriving in the wrong encoding. If you are getting the data from a database, make sure the database connection uses UTF-8.

If this is data from a file, make sure the file is encoded correctly as UTF-8. You can usually set this in the "Save as..." Dialog of the editor of your choice.

If the data is already broken when you view it in the source file, chances are that it used to be a UTF-8 file but was saved in the wrong encoding somewhere along the way.

Counting unique / distinct values by group in a data frame

You can just use the built-in R functions tapply with length

tapply(myvec$order_no, myvec$name, FUN = function(x) length(unique(x)))

How to create and add users to a group in Jenkins for authentication?

According to this posting by the lead Jenkins developer, Kohsuke Kawaguchi, in 2009, there is no group support for the built-in Jenkins user database. Group support is only usable when integrating Jenkins with LDAP or Active Directory. This appears to be the same in 2012.

However, as Vadim wrote in his answer, you don't need group support for the built-in Jenkins user database, thanks to the Role strategy plug-in.

How to get Map data using JDBCTemplate.queryForMap

To add to @BrianBeech's answer, this is even more trimmed down in java 8:

jdbcTemplate.query("select string1,string2 from table where x=1", (ResultSet rs) -> {
    HashMap<String,String> results = new HashMap<>();
    while (rs.next()) {
        results.put(rs.getString("string1"), rs.getString("string2"));
    }
    return results;
});

make a phone call click on a button

With permission:

Intent callIntent = new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse("tel:9875432100"));
if (ActivityCompat.checkSelfPermission(yourActivity.this,android.Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
                if (ActivityCompat.shouldShowRequestPermissionRationale(yourActivity.this,
                        android.Manifest.permission.CALL_PHONE)) {
                } else {
                    ActivityCompat.requestPermissions(yourActivity.this,
                            new String[]{android.Manifest.permission.CALL_PHONE},
                            MY_PERMISSIONS_REQUEST_CALL_PHONE);
                }
            }
startActivity(callIntent);

How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version

I had the same problem after switching to JDK 6 to compile a dependency module, then switched but to JDK 8.
Rerun the probject and compiler complained about unsupported major.minor version. I verified the Java version it was 1,8 for both the JVM and Maven.
After many tries and googling the problem was not solved, so i though what if i restart the computer (Windows 8) ?
I did restart, rerun the project again and problem was solved :)

"Insufficient Storage Available" even there is lot of free space in device memory

I have an un-rooted Nexus 4 (which has only internal storage, no SD card) and was getting this error with larger apps updating. Smaller apps would update fine.

I discovered that it was because I have recently signed up to the Play Music All Access service and had pinned several albums.

These are downloaded to the hidden /data partition and it was this that had run out of space (I assume)

I unpinned a couple of albums and now have no problems installing apps.

if (boolean == false) vs. if (!boolean)

Mostly READABILITY. When reading others code, it is much more intuitive to read as NOT CONTAINS KEY !values.containsKey(NoteColumns.CREATED_DATE) instead of reading CONTAINS KEY IS FALSE (values.containsKey(NoteColumns.CREATED_DATE) == false).

Tools to search for strings inside files without indexing

Original Answer

Windows Grep does this really well.

Edit: Windows Grep is no longer being maintained or made available by the developer. An alternate download link is here: Windows Grep - alternate

Current Answer

Visual Studio Code has excellent search and replace capabilities across files. It is extremely fast, supports regex and live preview before replacement.

enter image description here

What's the difference between getPath(), getAbsolutePath(), and getCanonicalPath() in Java?

In short:

  • getPath() gets the path string that the File object was constructed with, and it may be relative current directory.
  • getAbsolutePath() gets the path string after resolving it against the current directory if it's relative, resulting in a fully qualified path.
  • getCanonicalPath() gets the path string after resolving any relative path against current directory, and removes any relative pathing (. and ..), and any file system links to return a path which the file system considers the canonical means to reference the file system object to which it points.

Also, each of these has a File equivalent which returns the corresponding File object.

Note that IMO, Java got the implementation of an "absolute" path wrong; it really should remove any relative path elements in an absolute path. The canonical form would then remove any FS links or junctions in the path.

How to set socket timeout in C when making multiple connections?

connect timeout has to be handled with a non-blocking socket (GNU LibC documentation on connect). You get connect to return immediately and then use select to wait with a timeout for the connection to complete.

This is also explained here : Operation now in progress error on connect( function) error.

int wait_on_sock(int sock, long timeout, int r, int w)
{
    struct timeval tv = {0,0};
    fd_set fdset;
    fd_set *rfds, *wfds;
    int n, so_error;
    unsigned so_len;

    FD_ZERO (&fdset);
    FD_SET  (sock, &fdset);
    tv.tv_sec = timeout;
    tv.tv_usec = 0;

    TRACES ("wait in progress tv={%ld,%ld} ...\n",
            tv.tv_sec, tv.tv_usec);

    if (r) rfds = &fdset; else rfds = NULL;
    if (w) wfds = &fdset; else wfds = NULL;

    TEMP_FAILURE_RETRY (n = select (sock+1, rfds, wfds, NULL, &tv));
    switch (n) {
    case 0:
        ERROR ("wait timed out\n");
        return -errno;
    case -1:
        ERROR_SYS ("error during wait\n");
        return -errno;
    default:
        // select tell us that sock is ready, test it
        so_len = sizeof(so_error);
        so_error = 0;
        getsockopt (sock, SOL_SOCKET, SO_ERROR, &so_error, &so_len);
        if (so_error == 0)
            return 0;
        errno = so_error;
        ERROR_SYS ("wait failed\n");
        return -errno;
    }
}

How to read the last row with SQL Server

If you have a Replicated table, you can have an Identity=1000 in localDatabase and Identity=2000 in the clientDatabase, so if you catch the last ID you may find always the last from client, not the last from the current connected database. So the best method which returns the last connected database is:

SELECT IDENT_CURRENT('tablename')

How to convert a string variable containing time to time_t type in c++?

With C++11 you can now do

struct std::tm tm;
std::istringstream ss("16:35:12");
ss >> std::get_time(&tm, "%H:%M:%S"); // or just %T in this case
std::time_t time = mktime(&tm);

see std::get_time and strftime for reference

UIAlertController custom font, size, color

Swift 5.0

let titleAttrString = NSMutableAttributedString(string: "This is a title", attributes: [NSAttributedString.Key.font: UIFont(name: "CustomFontName", size: 17) as Any])
let messageAttrString = NSMutableAttributedString(string: "This is a message", attributes: [NSAttributedString.Key.font: UIFont(name: "CustomFontName", size: 13) as Any])

alertController.setValue(titleAttrString, forKey: "attributedTitle")
alertController.setValue(messageAttrString, forKey: "attributedMessage")

How to retrieve data from a SQL Server database in C#?

we can use this type of snippet also we generally use this kind of code for testing and validating data for DB to API fields

class Db
{
    private readonly static string ConnectionString =
            ConfigurationManager.ConnectionStrings
                        ["DbConnectionString"].ConnectionString;
    public static List<string> GetValuesFromDB(string LocationCode)
    {
        List<string> ValuesFromDB = new List<string>();
        string LocationqueryString = "select BELocationCode,CityLocation,CityLocationDescription,CountryCode,CountryDescription " +
            $"from [CustomerLocations] where LocationCode='{LocationCode}';";
        using (SqlConnection Locationconnection =
                                 new SqlConnection(ConnectionString))
        {
            SqlCommand command = new SqlCommand(LocationqueryString, Locationconnection);
            try
            {
                Locationconnection.Open();
                SqlDataReader Locationreader = command.ExecuteReader();
                while (Locationreader.Read())
                {
                    for (int i = 0; i <= Locationreader.FieldCount - 1; i++)
                    {
                        ValuesFromDB.Add(Locationreader[i].ToString());
                    }
                }
                Locationreader.Close();
                return ValuesFromDB;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                throw;
            }
        }

    }

}

hope this might helpful

Note: you guys need connection string (in our case "DbConnectionString")

Auto-center map with multiple markers in Google Maps API v3

Here's my take on this in case anyone comes across this thread:

This helps protect against non-numerical data destroying either of your final variables that determine lat and lng.

It works by taking in all of your coordinates, parsing them into separate lat and lng elements of an array, then determining the average of each. That average should be the center (and has proven true in my test cases.)

var coords = "50.0160001,3.2840073|50.014458,3.2778274|50.0169713,3.2750587|50.0180745,3.276742|50.0204038,3.2733474|50.0217796,3.2781737|50.0293064,3.2712542|50.0319918,3.2580816|50.0243287,3.2582281|50.0281447,3.2451177|50.0307925,3.2443178|50.0278165,3.2343882|50.0326574,3.2289809|50.0288569,3.2237612|50.0260081,3.2230589|50.0269495,3.2210104|50.0212645,3.2133541|50.0165868,3.1977592|50.0150515,3.1977341|50.0147901,3.1965286|50.0171915,3.1961636|50.0130074,3.1845098|50.0113267,3.1729483|50.0177206,3.1705726|50.0210692,3.1670394|50.0182166,3.158297|50.0207314,3.150927|50.0179787,3.1485753|50.0184944,3.1470782|50.0273077,3.149845|50.024227,3.1340514|50.0244172,3.1236235|50.0270676,3.1244474|50.0260853,3.1184879|50.0344525,3.113806";

var filteredtextCoordinatesArray = coords.split('|');    

    centerLatArray = [];
    centerLngArray = [];


    for (i=0 ; i < filteredtextCoordinatesArray.length ; i++) {

      var centerCoords = filteredtextCoordinatesArray[i]; 
      var centerCoordsArray = centerCoords.split(',');

      if (isNaN(Number(centerCoordsArray[0]))) {      
      } else {
        centerLatArray.push(Number(centerCoordsArray[0]));
      }

      if (isNaN(Number(centerCoordsArray[1]))) {
      } else {
        centerLngArray.push(Number(centerCoordsArray[1]));
      }                    

    }

    var centerLatSum = centerLatArray.reduce(function(a, b) { return a + b; });
    var centerLngSum = centerLngArray.reduce(function(a, b) { return a + b; });

    var centerLat = centerLatSum / filteredtextCoordinatesArray.length ; 
    var centerLng = centerLngSum / filteredtextCoordinatesArray.length ;                                    

    console.log(centerLat);
    console.log(centerLng);

    var mapOpt = {      
    zoom:8,
    center: {lat: centerLat, lng: centerLng}      
    };

File Upload using AngularJS

Above accepted answer is not browser compatible. If some one has compatibility issue try this.

Fiddle

View Code

 <div ng-controller="MyCtrl">
      <input type="file" id="file" name="file"/>
      <br>
      <button ng-click="add()">Add</button>
      <p>{{data}}</p>
    </div>

Controller code

var myApp = angular.module('myApp',[]);

function MyCtrl($scope) {
    $scope.data = 'none';    
    $scope.add = function(){
      var f = document.getElementById('file').files[0],
          r = new FileReader();
      r.onloadend = function(e){        
          var binary = "";
var bytes = new Uint8Array(e.target.result);
var length = bytes.byteLength;

for (var i = 0; i < length; i++) 
{
    binary += String.fromCharCode(bytes[i]);
}

$scope.data = (binary).toString();

          alert($scope.data);
      }
      r.readAsArrayBuffer(f);
    }
}

How to convert a column number (e.g. 127) into an Excel column (e.g. AA)

Here is how I would do it in Python. The algorithm is explained below:

alph = ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z')
def labelrec(n, res):
    if n<26:
        return alph[n]+res
    else:
        rem = n%26
        res = alph[rem]+res
        n = n/26-1
        return labelrec(n, res)

The function labelrec can be called with the number and an empty string like:

print labelrec(16383, '')

Here is why it works: If decimal numbers were written the same way as Excel sheet columns, number 0-9 would be written normally, but 10 would become '00' and then 20 would become '10' and so on. Mapping few numbers:

0 - 0

9 - 9

10 - 00

20 - 10

100 - 90

110 - 000

1110 - 0000

So, the pattern is clear. Starting at the unit's place, if a number is less than 10, it's representation is same as the number itself, else you need to adjust the remaining number by subtracting it by 1 and recurse. You can stop when the number is less than 10.

The same logic is applied for numbers of base 26 in above solution.

P.S. If you want the numbers to begin from 1, call the same function on input number after decreasing it by 1.

Initialize a long in Java
  1. You should add L: long i = 12345678910L;.
  2. Yes.

BTW: it doesn't have to be an upper case L, but lower case is confused with 1 many times :).

jQuery get the name of a select option

The Code is very Simple, Lets Put This Code

var name = $("#band_type_choices  option:selected").text();

Here You don't want to use $(this).find().text(), directly you can put your id name and add option:selected along with text().

This will return the result option name. Better Try this...

Converting a pointer into an integer
  1. #include <stdint.h>
  2. Use uintptr_t standard type defined in the included standard header file.

What is the best way to initialize a JavaScript Date to midnight?

Just going to add this here because I landed on this page looking for how to do this in moment.js and others may do too.

[Rationale: the word "moment" already appears elsewhere on this page so search engines direct here, and moment.js is widespread enough to warrant to being covered going on how often it is mentioned in other date-related SO questions]

So, in version 2.0.0 and above:

date.startOf('day');

For earlier versions:

date.sod();

Docs:

http://momentjs.com/docs/#/manipulating/start-of/

Laravel migration default value

Put the default value in single quote and it will work as intended. An example of migration: 

$table->increments('id');
            $table->string('name');
            $table->string('url');
            $table->string('country');
            $table->tinyInteger('status')->default('1');
            $table->timestamps();

EDIT : in your case ->default('100.0');

Switching users inside Docker image to a non-root user

You should also be able to do:

apt install sudo

sudo -i -u tomcat

Then you should be the tomcat user. It's not clear which Linux distribution you're using, but this works with Ubuntu 18.04 LTS, for example.

How to remove indentation from an unordered list item?

display:table-row; will also get rid of the indentation but will remove the bullets.

Directory.GetFiles: how to get only filename, not full path?

Have a look at using FileInfo.Name Property

something like

string[] files = Directory.GetFiles(dir); 

for (int iFile = 0; iFile < files.Length; iFile++)
    string fn = new FileInfo(files[iFile]).Name;

Also have a look at using DirectoryInfo Class and FileInfo Class

Retrofit 2 - URL Query Parameter

I am new to retrofit and I am enjoying it. So here is a simple way to understand it for those that might want to query with more than one query: The ? and & are automatically added for you.

Interface:

 public interface IService {

      String BASE_URL = "https://api.test.com/";
      String API_KEY = "SFSDF24242353434";

      @GET("Search") //i.e https://api.test.com/Search?
      Call<Products> getProducts(@Query("one") String one, @Query("two") String two,    
                                @Query("key") String key)
}

It will be called this way. Considering you did the rest of the code already.

  Call<Results> call = service.productList("Whatever", "here", IService.API_KEY);

For example, when a query is returned, it will look like this.

//-> https://api.test.com/Search?one=Whatever&two=here&key=SFSDF24242353434

Link to full project: Please star etc: https://github.com/Cosmos-it/ILoveZappos

If you found this useful, don't forget to star it please. :)

Jenkins returned status code 128 with github

To check are the following:

  1. if the right public key (id_rsa.pub) is uploaded to the git-server.
  2. if the right private key (id_rsa) is copied to /var/lib/jenkins/.ssh/
  3. if the known_hosts file is created inside ~/.ssh folder. Try ssh -vvv [email protected] to see debug logs. If thing goes well, github.com will be added to known_hosts.
  4. if the permission of id_rsa is set to 700 (chmod 700 id_rsa)

After all checks, try ssh -vvv [email protected].

Defining static const integer members in class definition

Here's another way to work around the problem:

std::min(9, int(test::N));

(I think Crazy Eddie's answer correctly describes why the problem exists.)

How to check empty object in angular 2 template using *ngIf

Above answers are okay. But I have found a really nice option to use following in the view:

{{previous_info?.title}}

probably duplicated question Angular2 - error if don't check if {{object.field}} exists

How to disable copy/paste from/to EditText

I've tested this solution and this works

    mSubdomainEditText.setLongClickable(false);
    mSubdomainEditText.setCustomSelectionActionModeCallback(new ActionMode.Callback() {

      public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        return false;
      }

      public void onDestroyActionMode(ActionMode mode) {
      }

      public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        return false;
      }

      public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        return false;
      }
    });

HTML5 form required attribute. Set custom validation message?

Note: This no longer works in Chrome, not tested in other browsers. See edits below. This answer is being left here for historical reference.

If you feel that the validation string really should not be set by code, you can set you input element's title attribute to read "This field cannot be left blank". (Works in Chrome 10)

title="This field should not be left blank."

See http://jsfiddle.net/kaleb/nfgfP/8/

And in Firefox, you can add this attribute:

x-moz-errormessage="This field should not be left blank."

Edit

This seems to have changed since I originally wrote this answer. Now adding a title does not change the validity message, it just adds an addendum to the message. The fiddle above still applies.

Edit 2

Chrome now does nothing with the title attribute as of Chrome 51. I am not sure in which version this changed.

How to avoid Number Format Exception in java?

I suggest to do 2 things:

  • validate the input on client side before passing it to the Servlet
  • catch the exception and show an error message within the user frontend as Tobiask mentioned. This case should normally not happen, but never trust your clients. ;-)

JAVA_HOME should point to a JDK not a JRE

For mac OS, this worked for me... none of the above solutions

$ vim .bash_profile

export JAVA_HOME=$(/usr/libexec/java_home)

$ source .bash_profile

Cannot find pkg-config error

for me, (OSX) the problem was solved doing this: 

brew install pkg-config

What is the canonical way to check for errors using the CUDA runtime API?

The C++-canonical way: Don't check for errors...use the C++ bindings which throw exceptions.

I used to be irked by this problem; and I used to have a macro-cum-wrapper-function solution just like in Talonmies and Jared's answers, but, honestly? It makes using the CUDA Runtime API even more ugly and C-like.

So I've approached this in a different and more fundamental way. For a sample of the result, here's part of the CUDA vectorAdd sample - with complete error checking of every runtime API call:

// (... prepare host-side buffers here ...)

auto current_device = cuda::device::current::get();
auto d_A = cuda::memory::device::make_unique<float[]>(current_device, numElements);
auto d_B = cuda::memory::device::make_unique<float[]>(current_device, numElements);
auto d_C = cuda::memory::device::make_unique<float[]>(current_device, numElements);

cuda::memory::copy(d_A.get(), h_A.get(), size);
cuda::memory::copy(d_B.get(), h_B.get(), size);

// (... prepare a launch configuration here... )

cuda::launch(vectorAdd, launch_config,
    d_A.get(), d_B.get(), d_C.get(), numElements
);    
cuda::memory::copy(h_C.get(), d_C.get(), size);

// (... verify results here...)

Again - all potential errors are checked , and an exception if an error occurred (caveat: If the kernel caused some error after launch, it will be caught after the attempt to copy the result, not before; to ensure the kernel was successful you would need to check for error between the launch and the copy with a cuda::outstanding_error::ensure_none() command).

The code above uses my

Thin Modern-C++ wrappers for the CUDA Runtime API library (Github)

Note that the exceptions carry both a string explanation and the CUDA runtime API status code after the failing call.

A few links to how CUDA errors are automagically checked with these wrappers:

regular expression for DOT

Use String.Replace() if you just want to replace the dots from string. Alternative would be to use Pattern-Matcher with StringBuilder, this gives you more flexibility as you can find groups that are between dots. If using the latter, i would recommend that you ignore empty entries with "\\.+".

public static int count(String str, String regex) {
    int i = 0;
    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher(str);
    while (m.find()) {
        m.group();
        i++;
    }
    return i;
}

public static void main(String[] args) {
    int i = 0, j = 0, k = 0;
    String str = "-.-..-...-.-.--..-k....k...k..k.k-.-";

    // this will just remove dots
    System.out.println(str.replaceAll("\\.", ""));
    // this will just remove sequences of ".." dots
    System.out.println(str.replaceAll("\\.{2}", ""));
    // this will just remove sequences of dots, and gets
    // multiple of dots as 1
    System.out.println(str.replaceAll("\\.+", ""));

    /* for this to be more obvious, consider following */
    System.out.println(count(str, "\\."));
    System.out.println(count(str, "\\.{2}"));
    System.out.println(count(str, "\\.+"));
}

The output will be:

--------kkkkk--
-.--.-.-.---kk.kk.k-.-
--------kkkkk--
21
7
11

React "after render" code?

For me, no combination of window.requestAnimationFrame or setTimeout produced consistent results. Sometimes it worked, but not always—or sometimes it would be too late.

I fixed it by looping window.requestAnimationFrame as many times as necessary.
(Typically 0 or 2-3 times)

The key is diff > 0: here we can ensure exactly when the page updates.

// Ensure new image was loaded before scrolling
if (oldH > 0 && images.length > prevState.images.length) {
    (function scroll() {
        const newH = ref.scrollHeight;
        const diff = newH - oldH;

        if (diff > 0) {
            const newPos = top + diff;
            window.scrollTo(0, newPos);
        } else {
            window.requestAnimationFrame(scroll);
        }
    }());
}

Why can't I change my input value in React even with the onChange listener

In React, the component will re-render (or update) only if the state or the prop changes.

In your case you have to update the state immediately after the change so that the component will re-render with the updates state value.

onTodoChange(event) {
        // update the state
    this.setState({name: event.target.value});
}

Delete from a table based on date

You could use:

DELETE FROM tableName
where your_date_column < '2009-01-01';

but Keep in mind that the above is really 

DELETE FROM tableName
    where your_date_column < '2009-01-01 00:00:00';

Not

 DELETE FROM tableName
        where your_date_column < '2009-01-01 11:59';

How do I get the first n characters of a string without checking the size or going out of bounds?

Use the substring method, as follows:

int n = 8;
String s = "Hello, World!";
System.out.println(s.substring(0,n);

If n is greater than the length of the string, this will throw an exception, as one commenter has pointed out. one simple solution is to wrap all this in the condition if(s.length()<n) in your else clause, you can choose whether you just want to print/return the whole String or handle it another way.

how to find seconds since 1970 in java

Based on your desire that 1317427200 be the output, there are several layers of issue to address.

  • First as others have mentioned, java already uses a UTC 1/1/1970 epoch. There is normally no need to calculate the epoch and perform subtraction unless you have weird locale rules.

  • Second, when you create a new Calendar it's initialized to 'now' so it includes the time of day. Changing the year/month/day doesn't affect the time of day fields. So if you want it to represent midnight of the date, you need to zero out the calendar before you set the date.

  • Third, you haven't specified how you're supposed to handle time zones. Daylight Savings can cause differences in the absolute number of seconds represented by a particular calendar-on-the-wall-date, depending on where your JVM is running. Since epoch is in UTC, we probably want to work in UTC times? You may need to seek clarification from the makers of the system you're interfacing with.

  • Fourth, months in Java are zero indexed. January is 0, October is 9.

Putting all that together

Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
calendar.clear();
calendar.set(2011, Calendar.OCTOBER, 1);
long secondsSinceEpoch = calendar.getTimeInMillis() / 1000L;

that will give you 1317427200

Distribution certificate / private key not installed

This answer is for "One Man" Team to solve this problem quickly without reading through too many information about "Team"

Step 1) Go to web browser, open your developer account. Go to Certificates, Identifiers & Profiles. Select Certificates / Production. You will see the certificate that was missing private key listed there. Click Revoke. And follow the instructions to remove this certificate. enter image description here Step 2) That's it! go back to Xcode to Validate you app. It will now ask you to generate a new certificate. Now you happily uploading your apps.

How to create and download a csv file from php script?

Try... csv download.

<?php 
mysql_connect('hostname', 'username', 'password');
mysql_select_db('dbname');
$qry = mysql_query("SELECT * FROM tablename");
$data = "";
while($row = mysql_fetch_array($qry)) {
  $data .= $row['field1'].",".$row['field2'].",".$row['field3'].",".$row['field4']."\n";
}

header('Content-Type: application/csv');
header('Content-Disposition: attachment; filename="filename.csv"');
echo $data; exit();
?>

Do I need Content-Type: application/octet-stream for file download?

No.

The content-type should be whatever it is known to be, if you know it. application/octet-stream is defined as "arbitrary binary data" in RFC 2046, and there's a definite overlap here of it being appropriate for entities whose sole intended purpose is to be saved to disk, and from that point on be outside of anything "webby". Or to look at it from another direction; the only thing one can safely do with application/octet-stream is to save it to file and hope someone else knows what it's for.

You can combine the use of Content-Disposition with other content-types, such as image/png or even text/html to indicate you want saving rather than display. It used to be the case that some browsers would ignore it in the case of text/html but I think this was some long time ago at this point (and I'm going to bed soon so I'm not going to start testing a whole bunch of browsers right now; maybe later).

RFC 2616 also mentions the possibility of extension tokens, and these days most browsers recognise inline to mean you do want the entity displayed if possible (that is, if it's a type the browser knows how to display, otherwise it's got no choice in the matter). This is of course the default behaviour anyway, but it means that you can include the filename part of the header, which browsers will use (perhaps with some adjustment so file-extensions match local system norms for the content-type in question, perhaps not) as the suggestion if the user tries to save.

Hence:

Content-Type: application/octet-stream
Content-Disposition: attachment; filename="picture.png"

Means "I don't know what the hell this is. Please save it as a file, preferably named picture.png".

Content-Type: image/png
Content-Disposition: attachment; filename="picture.png"

Means "This is a PNG image. Please save it as a file, preferably named picture.png".

Content-Type: image/png
Content-Disposition: inline; filename="picture.png"

Means "This is a PNG image. Please display it unless you don't know how to display PNG images. Otherwise, or if the user chooses to save it, we recommend the name picture.png for the file you save it as".

Of those browsers that recognise inline some would always use it, while others would use it if the user had selected "save link as" but not if they'd selected "save" while viewing (or at least IE used to be like that, it may have changed some years ago).

Table 'mysql.user' doesn't exist:ERROR

Try run mysqladmin reload, which is located in /usr/loca/mysql/bin/ on mac.

How can I set the focus (and display the keyboard) on my EditText programmatically

 
final EditText tb = new EditText(this);
tb.requestFocus();
tb.postDelayed(new Runnable() {
    @Override
    public void run() {
        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        inputMethodManager.showSoftInput(tb, InputMethodManager.SHOW_IMPLICIT);
    }
}, 1000);

serialize/deserialize java 8 java.time with Jackson JSON mapper

There's no need to use custom serializers/deserializers here. Use jackson-modules-java8's datetime module:

Datatype module to make Jackson recognize Java 8 Date & Time API data types (JSR-310).

This module adds support for quite a few classes:

  • Duration
  • Instant
  • LocalDateTime
  • LocalDate
  • LocalTime
  • MonthDay
  • OffsetDateTime
  • OffsetTime
  • Period
  • Year
  • YearMonth
  • ZonedDateTime
  • ZoneId
  • ZoneOffset

stringstream, string, and char* conversion confusion

What you're doing is creating a temporary. That temporary exists in a scope determined by the compiler, such that it's long enough to satisfy the requirements of where it's going.

As soon as the statement const char* cstr2 = ss.str().c_str(); is complete, the compiler sees no reason to keep the temporary string around, and it's destroyed, and thus your const char * is pointing to free'd memory.

Your statement string str(ss.str()); means that the temporary is used in the constructor for the string variable str that you've put on the local stack, and that stays around as long as you'd expect: until the end of the block, or function you've written. Therefore the const char * within is still good memory when you try the cout.

Understanding __get__ and __set__ and Python descriptors

Why do I need the descriptor class?

It gives you extra control over how attributes work. If you're used to getters and setters in Java, for example, then it's Python's way of doing that. One advantage is that it looks to users just like an attribute (there's no change in syntax). So you can start with an ordinary attribute and then, when you need to do something fancy, switch to a descriptor.

An attribute is just a mutable value. A descriptor lets you execute arbitrary code when reading or setting (or deleting) a value. So you could imagine using it to map an attribute to a field in a database, for example – a kind of ORM.

Another use might be refusing to accept a new value by throwing an exception in __set__ – effectively making the "attribute" read only.

What is instance and owner here? (in __get__). What is the purpose of these parameters?

This is pretty subtle (and the reason I am writing a new answer here - I found this question while wondering the same thing and didn't find the existing answer that great).

A descriptor is defined on a class, but is typically called from an instance. When it's called from an instance both instance and owner are set (and you can work out owner from instance so it seems kinda pointless). But when called from a class, only owner is set – which is why it's there.

This is only needed for __get__ because it's the only one that can be called on a class. If you set the class value you set the descriptor itself. Similarly for deletion. Which is why the owner isn't needed there.

How would I call/use this example?

Well, here's a cool trick using similar classes:

class Celsius:

    def __get__(self, instance, owner):
        return 5 * (instance.fahrenheit - 32) / 9

    def __set__(self, instance, value):
        instance.fahrenheit = 32 + 9 * value / 5


class Temperature:

    celsius = Celsius()

    def __init__(self, initial_f):
        self.fahrenheit = initial_f


t = Temperature(212)
print(t.celsius)
t.celsius = 0
print(t.fahrenheit)

(I'm using Python 3; for python 2 you need to make sure those divisions are / 5.0 and / 9.0). That gives:

100.0
32.0

Now there are other, arguably better ways to achieve the same effect in python (e.g. if celsius were a property, which is the same basic mechanism but places all the source inside the Temperature class), but that shows what can be done...

How to generate random positive and negative numbers in Java

([my double-compatible primitive type here])(Math.random() * [my max value here] * (Math.random() > 0.5 ? 1 : -1))

example:

// need a random number between -500 and +500
long myRandomLong = (long)(Math.random() * 500 * (Math.random() > 0.5 ? 1 : -1));

iPad/iPhone hover problem causes the user to double click a link

This short snippet seems to work. Trigger the click event when link tapped :

  $('a').on('touchstart', function() {
    $(this).trigger('click');
  });

how to save DOMPDF generated content to file?

I have just used dompdf and the code was a little different but it worked.

Here it is:

require_once("./pdf/dompdf_config.inc.php");
$files = glob("./pdf/include/*.php");
foreach($files as $file) include_once($file);

$html =
      '<html><body>'.
      '<p>Put your html here, or generate it with your favourite '.
      'templating system.</p>'.
      '</body></html>';

    $dompdf = new DOMPDF();
    $dompdf->load_html($html);
    $dompdf->render();
    $output = $dompdf->output();
    file_put_contents('Brochure.pdf', $output);

Only difference here is that all of the files in the include directory are included.

Other than that my only suggestion would be to specify a full directory path for writing the file rather than just the filename.

How to list active / open connections in Oracle?

 
select status, count(1) as connectionCount from V$SESSION group by status;

Java client certificates over HTTPS/SSL

I use the Apache commons HTTP Client package to do this in my current project and it works fine with SSL and a self-signed cert (after installing it into cacerts like you mentioned). Please take a look at it here:

http://hc.apache.org/httpclient-3.x/tutorial.html

http://hc.apache.org/httpclient-3.x/sslguide.html

XmlSerializer giving FileNotFoundException at constructor

Believe it or not, this is normal behaviour. An exception is thrown but handled by the XmlSerializer, so if you just ignore it everything should continue on fine.

I have found this very annoying, and there have been many complaints about this if you search around a bit, but from what I've read Microsoft don't plan on doing anything about it.

You can avoid getting Exception popups all the time while debugging if you switch off first chance exceptions for that specific exception. In Visual Studio, go to Debug -> Exceptions (or press Ctrl + Alt + E), Common Language Runtime Exceptions -> System.IO -> System.IO.FileNotFoundException.

You can find information about another way around it in the blog post C# XmlSerializer FileNotFound exception (which discusses Chris Sells' tool XmlSerializerPreCompiler).

Play/pause HTML 5 video using JQuery

For pausing multiple videos I have found that this works nicely:

$("video").each(function(){
    $(this).get(0).pause();
});

This can be put into a click function which is quite handy.

How to install Laravel's Artisan?

While you are working with Laravel you must be in root of laravel directory structure. There are App, route, public etc folders is root directory. Just follow below step to fix issue. check composer status using : composer -v

First, download the Laravel installer using Composer:

composer global require "laravel/installer"

Please check with below command:

php artisan serve

still not work then create new project with existing code. using LINK

Is It Possible to NSLog C Structs (Like CGRect or CGPoint)?

Yes, you can use bellow few functions like: First you have to convert CGPoint struct into string, see example

1) NSStringFromCGPoint,  
2) NSStringFromCGSize,  
3) NSStringFromCGRect,  
4) NSStringFromCGAffineTransform,  
5) NSStringFromUIEdgeInsets,

For example:

1) NSLog(@"NSStringFromCGPoint = %@", NSStringFromCGRect(cgPointValue));

Like this...

Convert array values from string to int?

If you have a multi-dimensional array, none of the previously mentioned solutions will work. Here is my solution:

public function arrayValuesToInt(&$array){
  if(is_array($array)){
    foreach($array as &$arrayPiece){
      arrayValuesToInt($arrayPiece);
    }
  }else{
    $array = intval($array);
  }
}

Then, just do this:

arrayValuesToInt($multiDimentionalArray);

This will make an array like this:

[["1","2"]["3","4"]]

look like this:

[[1,2][3,4]]

This will work with any level of depth.

Alternatively, you can use array_walk_recursive() for a shorter answer:

array_walk_recursive($array, function(&$value){
    $value = intval($value);
});

how to use JSON.stringify and json_decode() properly

When you save some data using JSON.stringify() and then need to read that in php. The following code worked for me.

json_decode( html_entity_decode( stripslashes ($jsonString ) ) );

Thanks to @Thisguyhastwothumbs

What does "var" mean in C#?

It declares a type based on what is assigned to it in the initialisation.

A simple example is that the code:

var i = 53;

Will examine the type of 53, and essentially rewrite this as:

int i = 53;

Note that while we can have:

long i = 53;

This won't happen with var. Though it can with:

var i = 53l; // i is now a long

Similarly:

var i = null; // not allowed as type can't be inferred.
var j = (string) null; // allowed as the expression (string) null has both type and value.

This can be a minor convenience with complicated types. It is more important with anonymous types:

var i = from x in SomeSource where x.Name.Length > 3 select new {x.ID, x.Name};
foreach(var j in i)
  Console.WriteLine(j.ID.ToString() + ":" + j.Name);

Here there is no other way of defining i and j than using var as there is no name for the types that they hold.

Find document with array that contains a specific value

Incase of lookup_food_array is array.

match_stage["favoriteFoods"] = {'$elemMatch': {'$in': lookup_food_array}}

Incase of lookup_food_array is string.

match_stage["favoriteFoods"] = {'$elemMatch': lookup_food_string}

Undefined symbols for architecture i386

At the risk of sounding obvious, always check the spelling of your forward class files. Sometimes XCode (at least XCode 4.3.2) will turn a declaration green that's actually camel cased incorrectly. Like in this example:

"_OBJC_CLASS_$_RadioKit", referenced from:
  objc-class-ref in RadioPlayerViewController.o

If RadioKit was a class file and you make it a property of another file, in the interface declaration, you might see that

Radiokit *rk;

has "Radiokit" in green when the actual decalaration should be:

RadioKit *rk;

This error will also throw this type of error. Another example (in my case), is when you have _iPhone and _iphone extensions on your class names for universal apps. Once I changed the appropriate file from _iphone to the correct _iPhone, the errors went away.

Getting java.net.SocketTimeoutException: Connection timed out in android

Set This in OkHttpClient.Builder() Object

val httpClient = OkHttpClient.Builder()
        httpClient.connectTimeout(5, TimeUnit.MINUTES) // connect timeout
            .writeTimeout(5, TimeUnit.MINUTES) // write timeout
            .readTimeout(5, TimeUnit.MINUTES) // read timeout