Programs & Examples On #Referrals

Accessing the last entry in a Map

In such scenario last used key is usually known so it can be used for accessing last value (inserted with the one):

class PostIndexData {
    String _office_name;
    Boolean _isGov;
    public PostIndexData(String name, Boolean gov) {
        _office_name = name;
        _isGov = gov;
class KgpData {
    String _postIndex;
    PostIndexData _postIndexData;
    public KgpData(String postIndex, PostIndexData postIndexData) {
        _postIndex = postIndex;
        _postIndexData = postIndexData;;

public class Office2ASMPro {
    private HashMap<String,PostIndexData> _postIndexMap = new HashMap<>();
    private HashMap<String,KgpData> _kgpMap = new HashMap<>();
private void addOffice(String kgp, String postIndex, String officeName, Boolean gov) {
            if (_postIndexMap.get(postIndex) == null) {
                _postIndexMap.put(postIndex, new PostIndexData(officeName, gov));
            _kgpMap.put( kgp, new KgpData(postIndex, _postIndexMap.get(postIndex)) );

Update Angular model after setting input value with jQuery

If you are using IE, you have to use: input.trigger("change");

'ng' is not recognized as an internal or external command, operable program or batch file

You should not add C:\Users\Administrator\AppData\Roaming\npm\node_modules\angular-cli\bin\ng to your PATH. There is only a javascript file which you cannot use in terminal.

You need ng.cmd which is probably located at %AppData%\Roaming\npm. Make sure this path is included in your PATH variable.

NameError: name 'datetime' is not defined

It can also be used as below:

from datetime import datetime
start_date = datetime(2016,3,1)
end_date = datetime(2016,3,10)

Bootstrap 3 - jumbotron background image effect


One way to achieve this is using a position:fixed container for the background image and place it outside of the .jumbotron. Make the bg container the same height as the .jumbotron and center the background image:

background: url('/assets/example/...jpg') no-repeat center center;


.bg {
  background: url('/assets/example/bg_blueplane.jpg') no-repeat center center;
  position: fixed;
  width: 100%;
  height: 350px; /*same height as jumbotron */
  z-index: -1;

.jumbotron {
  margin-bottom: 0px;
  height: 350px;
  color: white;
  text-shadow: black 0.3em 0.3em 0.3em;

Then use jQuery to decrease the height of the .jumbtron as the window scrolls. Since the background image is centered in the DIV it will adjust accordingly -- creating a parallax affect.


var jumboHeight = $('.jumbotron').outerHeight();
function parallax(){
    var scrolled = $(window).scrollTop();
    $('.bg').css('height', (jumboHeight-scrolled) + 'px');



Getting file names without extensions

You can use Path.GetFileNameWithoutExtension:

foreach (FileInfo fi in smFiles)
    builder.Append(", ");

Although I am surprised there isn't a way to get this directly from the FileInfo (or at least I can't see it).

git repo says it's up-to-date after pull but files are not updated

For me my forked branch was not in sync with the master branch. So I went to bitbucket and synced and merged my forked branch and then tried to take the pull. Then it worked fine.

Get a Windows Forms control by name in C#

Assuming you have the menuStrip object and the menu is only one level deep, use:

ToolStripMenuItem item = menuStrip.Items
    .SelectMany(it => it.DropDownItems.OfType<ToolStripMenuItem>())
    .SingleOrDefault(n => n.Name == "MyMenu");

For deeper menu levels add more SelectMany operators in the statement.

if you want to search all menu items in the strip then use

ToolStripMenuItem item = menuStrip.Items

However, make sure each menu has a different name to avoid exception thrown by key duplicates.

To avoid exceptions you could use FirstOrDefault instead of SingleOrDefault / Single, or just return a sequence if you might have Name duplicates.

Print in one line dynamically

I think a simple join should work:

nl = []
for x in range(1,10):nl.append(str(x))
print ' '.join(nl)

Display Adobe pdf inside a div

You can use the Javascript library PDF.JS to display a PDF inside a div. The size of the PDF can be adjusted according to the size of the div. You can also setup event handlers for moving to next / previous pages of the PDF.

You can checkout PDF.JS Tutorial - How to display a PDF with Javascript to see how PDF.JS can be integrated in your HTML code.

Difference between static memory allocation and dynamic memory allocation

There are three types of allocation — static, automatic, and dynamic.

Static Allocation means, that the memory for your variables is allocated when the program starts. The size is fixed when the program is created. It applies to global variables, file scope variables, and variables qualified with static defined inside functions.

Automatic memory allocation occurs for (non-static) variables defined inside functions, and is usually stored on the stack (though the C standard doesn't mandate that a stack is used). You do not have to reserve extra memory using them, but on the other hand, have also limited control over the lifetime of this memory. E.g: automatic variables in a function are only there until the function finishes.

void func() {
    int i; /* `i` only exists during `func` */

Dynamic memory allocation is a bit different. You now control the exact size and the lifetime of these memory locations. If you don't free it, you'll run into memory leaks, which may cause your application to crash, since at some point of time, system cannot allocate more memory.

int* func() {
    int* mem = malloc(1024);
    return mem;

int* mem = func(); /* still accessible */

In the upper example, the allocated memory is still valid and accessible, even though the function terminated. When you are done with the memory, you have to free it:


Converting Numpy Array to OpenCV Array

The simplest solution would be to use Pillow lib:

from PIL import Image

image = Image.fromarray(<your_numpy_array>.astype(np.uint8))

And you can use it as an image.

Given a DateTime object, how do I get an ISO 8601 date in string format?

As mentioned in other answer, DateTime has issues by design.


I suggest to use NodaTime to manage date/time values:

  • Local time, date, datetime
  • Global time
  • Time with timezone
  • Period
  • Duration


So, to create and format ZonedDateTime you can use the following code snippet:

var instant1 = Instant.FromUtc(2020, 06, 29, 10, 15, 22);

var utcZonedDateTime = new ZonedDateTime(instant1, DateTimeZone.Utc);
utcZonedDateTime.ToString("yyyy-MM-ddTHH:mm:ss'Z'", CultureInfo.InvariantCulture);
// 2020-06-29T10:15:22Z

var instant2 = Instant.FromDateTimeUtc(new DateTime(2020, 06, 29, 10, 15, 22, DateTimeKind.Utc));

var amsterdamZonedDateTime = new ZonedDateTime(instant2, DateTimeZoneProviders.Tzdb["Europe/Amsterdam"]);
amsterdamZonedDateTime.ToString("yyyy-MM-ddTHH:mm:ss'Z'", CultureInfo.InvariantCulture);
// 2020-06-29T12:15:22Z

For me NodaTime code looks quite verbose. But types are really useful. They help to handle date/time values correctly.


To use NodaTime with Newtonsoft.Json you need to add reference to NodaTime.Serialization.JsonNet NuGet package and configure JSON options.

    .AddJsonOptions(options =>
        var settings=options.SerializerSettings;
        settings.DateParseHandling = DateParseHandling.None;

hadoop No FileSystem for scheme: file

Another possible cause (though the OPs question doesn't itself suffer from this) is if you create a configuration instance that does not load the defaults:

Configuration config = new Configuration(false);

If you don't load the defaults then you won't get the default settings for things like the FileSystem implementations which leads to identical errors like this when trying to access HDFS. Switching to the parameterless constructor of passing in true to load defaults may resolve this.

Additionally if you are adding custom configuration locations (e.g. on the file system) to the Configuration object be careful of which overload of addResource() you use. For example if you use addResource(String) then Hadoop assumes that the string is a class path resource, if you need to specify a local file try the following:

File configFile = new File("example/config.xml");
config.addResource(new Path("file://" + configFile.getAbsolutePath()));

How to Update/Drop a Hive Partition?

You can either copy files into the folder where external partition is located or use

INSERT OVERWRITE TABLE tablename1 PARTITION (partcol1=val1, partcol2=val2...)...


Laravel: How to Get Current Route Name? (v5 ... v7)

I have used for getting route name in larvel 5.3


How to check if the string is empty?

a = ''
b = '   '
a.isspace() -> False
b.isspace() -> True

Create a simple HTTP server with Java?

This is how I would go about this:

  1. Start a ServerSocket listening (probably on port 80).
  2. Once you get a connection request, accept and pass to another thread/process (this leaves your ServerSocket available to keep listening and accept other connections).
  3. Parse the request text (specifically, the headers where you will see if it is a GET or POST, and the parameters passed.
  4. Answer with your own headers (Content-Type, etc.) and the HTML.

I find it useful to use Firebug (in Firefox) to see examples of headers. This is what you want to emulate.

Try this link: - Multithreaded Server in Java

How to check if an element is visible with WebDriver

If you're using C#, it would be driver.Displayed. Here's an example from my own project:

if (!driver.FindElement(By.Name("newtagfield")).Displayed)      //if the tag options is not displayed
    driver.FindElement(By.Id("expand-folder-tags")).Click();    //make sure the folder and tags options are visible

How can I render HTML from another file in a React component?

It is common to have components that are only rendering from props. Like this:

class Template extends React.Component{
  render (){
    return <div>this.props.something</div>

Then in your upper level component where you have the logic you just import the Template component and pass the needed props. All your logic stays in the higher level component, and the Template only renders. This is a possible way to achieve 'templates' like in Angular.

There is no way to have .jsx file with jsx only and use it in React because jsx is not really html but markup for a virtual DOM, which React manages.

React Native fetch() Network Request Failed

I was using localhost for the address, which was obviously wrong. After replacing it with the IP address of the server (in the network that emulator is), it worked perfectly.


In Android Emulator, the address of the development machine is More explanation here

For Genymotion, the address is More info here

How to generate random number in Bash?

There is $RANDOM. I don't know exactly how it works. But it works. For testing, you can do :

echo $RANDOM

View content of H2 or HSQLDB in-memory database

For HSQLDB, The following worked for me:


And this brought up the GUI with my tables and data once I pointed it to the right named in-mem database.

It is basically the equivalent of newing up a DatabaseManager (the non Swing variety), which prompts for connection details, and is set to --noexit)

I also tried the Swing version, but it only had a main, and I was unsure of the arguments to pass. If anyone knows, please post here.

Just because I searched for hours for the right database name: The name of the database is the name of your datasource. So try with URL jdbc:hsqldb:mem:dataSource if you have a data source bean with id=dataSource. If this does not work, try testdb which is the default.

How can I list all cookies for the current page with Javascript?

var x = document.cookie; 

This displays every cookie the current site has access to. If you for example have created two cookies "username=Frankenstein" and "username=Dracula", these two lines of code will display "username=Frankenstein; username=Dracula". However, information such as expiry date will not be shown.

How do you pass a function as a parameter in C?

Pass address of a function as parameter to another function as shown below

#include <stdio.h>

void print();
void execute(void());

int main()
    execute(print); // sends address of print
    return 0;

void print()

void execute(void f()) // receive address of print

Also we can pass function as parameter using function pointer

#include <stdio.h>

void print();
void execute(void (*f)());

int main()
    execute(&print); // sends address of print
    return 0;

void print()

void execute(void (*f)()) // receive address of print

How can I format bytes a cell in Excel as KB, MB, GB etc?

You can't really do calculations in the formatting features of Excel. You can use something like the following to do a rough estimation though:

[<500000]#,##0" B";[<500000000]#,##0,," MB";#,##0,,," GB"

When to use in vs ref vs out

Below are some notes which i pulled from this codeproject article on C# Out Vs Ref

  1. It should be used only when we are expecting multiple outputs from a function or a method. A thought on structures can be also a good option for the same.
  2. REF and OUT are keywords which dictate how data is passed from caller to callee and vice versa.
  3. In REF data passes two way. From caller to callee and vice-versa.
  4. In Out data passes only one way from callee to caller. In this case if Caller tried to send data to the callee it will be overlooked / rejected.

If you are a visual person then please see this yourtube video which demonstrates the difference practically

Below image shows the differences more visually

C# Out Vs Ref

Adding value labels on a matplotlib bar chart

Based on a feature mentioned in this answer to another question I have found a very generally applicable solution for placing labels on a bar chart.

Other solutions unfortunately do not work in many cases, because the spacing between label and bar is either given in absolute units of the bars or is scaled by the height of the bar. The former only works for a narrow range of values and the latter gives inconsistent spacing within one plot. Neither works well with logarithmic axes.

The solution I propose works independent of scale (i.e. for small and large numbers) and even correctly places labels for negative values and with logarithmic scales because it uses the visual unit points for offsets.

I have added a negative number to showcase the correct placement of labels in such a case.

The value of the height of each bar is used as a label for it. Other labels can easily be used with Simon's for rect, label in zip(rects, labels) snippet.

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

# Bring some raw data.
frequencies = [6, -16, 75, 160, 244, 260, 145, 73, 16, 4, 1]

# In my original code I create a series and run on that,
# so for consistency I create a series from the list.
freq_series = pd.Series.from_array(frequencies)

x_labels = [108300.0, 110540.0, 112780.0, 115020.0, 117260.0, 119500.0,
            121740.0, 123980.0, 126220.0, 128460.0, 130700.0]

# Plot the figure.
plt.figure(figsize=(12, 8))
ax = freq_series.plot(kind='bar')
ax.set_title('Amount Frequency')
ax.set_xlabel('Amount ($)')

def add_value_labels(ax, spacing=5):
    """Add labels to the end of each bar in a bar chart.

        ax (matplotlib.axes.Axes): The matplotlib object containing the axes
            of the plot to annotate.
        spacing (int): The distance between the labels and the bars.

    # For each bar: Place a label
    for rect in ax.patches:
        # Get X and Y placement of label from rect.
        y_value = rect.get_height()
        x_value = rect.get_x() + rect.get_width() / 2

        # Number of points between bar and label. Change to your liking.
        space = spacing
        # Vertical alignment for positive values
        va = 'bottom'

        # If value of bar is negative: Place label below bar
        if y_value < 0:
            # Invert space to place label below
            space *= -1
            # Vertically align label at top
            va = 'top'

        # Use Y value as label and format number with one decimal place
        label = "{:.1f}".format(y_value)

        # Create annotation
            label,                      # Use `label` as label
            (x_value, y_value),         # Place label at end of the bar
            xytext=(0, space),          # Vertically shift label by `space`
            textcoords="offset points", # Interpret `xytext` as offset in points
            ha='center',                # Horizontally center label
            va=va)                      # Vertically align label differently for
                                        # positive and negative values.

# Call the function above. All the magic happens there.


Edit: I have extracted the relevant functionality in a function, as suggested by barnhillec.

This produces the following output:

Bar chart with automatically placed labels on each bar

And with logarithmic scale (and some adjustment to the input data to showcase logarithmic scaling), this is the result:

Bar chart with logarithmic scale with automatically placed labels on each bar

How to Find And Replace Text In A File With C#

This is how I did it with a large (50 GB) file:

I tried 2 different ways: the first, reading the file into memory and using Regex Replace or String Replace. Then I appended the entire string to a temporary file.

The first method works well for a few Regex replacements, but Regex.Replace or String.Replace could cause out of memory error if you do many replaces in a large file.

The second is by reading the temp file line by line and manually building each line using StringBuilder and appending each processed line to the result file. This method was pretty fast.

static void ProcessLargeFile()
        if (File.Exists(outFileName)) File.Delete(outFileName);

        string text = File.ReadAllText(inputFileName, Encoding.UTF8);

        // EX 1 This opens entire file in memory and uses Replace and Regex Replace --> might cause out of memory error

        text = text.Replace("</text>", "");

        text = Regex.Replace(text, @"\<ref.*?\</ref\>", "");

        File.WriteAllText(outFileName, text);

        // EX 2 This reads file line by line 

        if (File.Exists(outFileName)) File.Delete(outFileName);

        using (var sw = new StreamWriter(outFileName))      
        using (var fs = File.OpenRead(inFileName))
        using (var sr = new StreamReader(fs, Encoding.UTF8)) //use UTF8 encoding or whatever encoding your file uses
            string line, newLine;

            while ((line = sr.ReadLine()) != null)
              //note: call your own replace function or use String.Replace here 
              newLine = Util.ReplaceDoubleBrackets(line);


    public static string ReplaceDoubleBrackets(string str)
        //note: this replaces the first occurrence of a word delimited by [[ ]]

        //replace [[ with your own delimiter
        if (str.IndexOf("[[") < 0)
            return str;

        StringBuilder sb = new StringBuilder();

        //this part gets the string to replace, put this in a loop if more than one occurrence  per line.
        int posStart = str.IndexOf("[[");
        int posEnd = str.IndexOf("]]");
        int length = posEnd - posStart;

        // ... code to replace with newstr


        return sb.ToString();

How to use GROUP BY to concatenate strings in MySQL?


Will give you a comma-delimited string

Check if a number is int or float

how about this solution?

if type(x) in (float, int):
    # do whatever
    # do whatever

How to reload the datatable(jquery) data?

None of these solutions worked for me, but I did do something similar to Masood's answer. Here it is for posterity. This assumes you have <table id="mytable"></table> in your page somewhere:

function generate_support_user_table() {
            "bDestroy": true,
            "fnInitComplete": function () { $('#support_user_table').show(); },

The important parts are:

  1. bDestroy, which wipes out the current table before loading.
  2. The hide() call and fnInitComplete, which ensures that the table only appears after everything is loaded. Otherwise it resizes and looks weird while loading.

Just add the function call to $(document).ready() and you should be all set. It will load the table initially, as well as reload later on a button click or whatever.

xxxxxx.exe is not a valid Win32 application

I believe this error can also be thrown if your project is targeting a framework version that is not installed on the server you are deploying to.

"The import org.springframework cannot be resolved."

Finally my issue got resolved. I was importing the project as "Existing project into workspace". This was completely wrong. After that I selected "Existing Maven project" and after that some few hiccups and all errors were removed. In this process I got to learn so many things in Maven which are important for a new comer in Maven project.

how do I initialize a float to its max/min value?

You can either use -FLT_MAX (or -DBL_MAX) for the maximum magnitude negative number and FLT_MAX (or DBL_MAX) for positive. This gives you the range of possible float (or double) values.

You probably don't want to use FLT_MIN; it corresponds to the smallest magnitude positive number that can be represented with a float, not the most negative value representable with a float.

FLT_MIN and FLT_MAX correspond to std::numeric_limits<float>::min() and std::numeric_limits<float>::max().

In Postgresql, force unique on combination of two columns

Create unique constraint that two numbers together CANNOT together be repeated:

ADD UNIQUE (col1, col2)

DataGridView AutoFit and Fill

This is what I have done in order to get the column "first_name" fill the space when all the columns cannot do it.

When the grid go to small the column "first_name" gets almost invisible (very thin) so I can set the DataGridViewAutoSizeColumnMode to AllCells as the others visible columns. For performance issues it´s important to set them to None before data binding it and set back to AllCell in the DataBindingComplete event handler of the grid. Hope it helps!

private void dataGridView1_Resize(object sender, EventArgs e)
        int ColumnsWidth = 0;
        foreach(DataGridViewColumn col in dataGridView1.Columns)
            if (col.Visible) ColumnsWidth += col.Width;

        if (ColumnsWidth <dataGridView1.Width)
            dataGridView1.Columns["first_name"].AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
        else if (dataGridView1.Columns["first_name"].Width < 10) dataGridView1.Columns["first_name"].AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells;

angular js unknown provider

To add my own experience in here, I was trying to inject a service into one of my module config functions. This paragraph from the docs which I eventually found explains why that doesn't work:

During application bootstrap, before Angular goes off creating all services, it configures and instantiates all providers. We call this the configuration phase of the application life-cycle. During this phase, services aren't accessible because they haven't been created yet.

Meaning you can inject providers into module.config(...) functions, but you can't inject services, for that you need to wait until, or expose a provider you can inject to module.config

How to get the nvidia driver version from the command line?

Windows version:

cd \Program Files\NVIDIA Corporation\NVSMI


Correct Semantic tag for copyright info - html5

Put it inside your <footer> by all means, but the most fitting element is the small element.

The HTML5 spec for this says:

Small print typically features disclaimers, caveats, legal restrictions, or copyrights. Small print is also sometimes used for attribution, or for satisfying licensing requirements.

Writing to an Excel spreadsheet

  • xlrd/xlwt (standard): Python does not have this functionality in it's standard library, but I think of xlrd/xlwt as the "standard" way to read and write excel files. It is fairly easy to make a workbook, add sheets, write data/formulas, and format cells. If you need all of these things, you may have the most success with this library. I think you could choose openpyxl instead and it would be quite similar, but I have not used it.

    To format cells with xlwt, define a XFStyle and include the style when you write to a sheet. Here is an example with many number formats. See example code below.

  • Tablib (powerful, intuitive): Tablib is a more powerful yet intuitive library for working with tabular data. It can write excel workbooks with multiple sheets as well as other formats, such as csv, json, and yaml. If you don't need formatted cells (like background color), you will do yourself a favor to use this library, which will get you farther in the long run.

  • csv (easy): Files on your computer are either text or binary. Text files are just characters, including special ones like newlines and tabs, and can be easily opened anywhere (e.g. notepad, your web browser, or Office products). A csv file is a text file that is formatted in a certain way: each line is a list of values, separated by commas. Python programs can easily read and write text, so a csv file is the easiest and fastest way to export data from your python program into excel (or another python program).

    Excel files are binary and require special libraries that know the file format, which is why you need an additional library for python, or a special program like Microsoft Excel, Gnumeric, or LibreOffice, to read/write them.

import xlwt

style = xlwt.XFStyle()
style.num_format_str = '0.00E+00'


for i,n in enumerate(list1):
    sheet1.write(i, 0, n, fmt)

javascript close current window

I suggest to put id to the input, and close the window by callback function as the following:

<input id="close_window" type="button" class="btn btn-success"
                   style="font-weight: bold;display: inline;"

The callback function as the following:

   $('#close_window').on('click', function(){
      window.opener = self;

I think sometimes onclick doesn't work, check the following answer also.

How to check if element in groovy array/hash/collection/list?

If you really want your includes method on an ArrayList, just add it:

ArrayList.metaClass.includes = { i -> i in delegate }

Center the nav in Twitter Bootstrap

For Bootstrap v4 check this:

only add class to ul.pagination:

  <ul class="pagination justify-content-center">
    <li class="page-item disabled">
      <a class="page-link" href="#" tabindex="-1">Previous</a>
    <li class="page-item"><a class="page-link" href="#">1</a></li>
    <li class="page-item"><a class="page-link" href="#">2</a></li>
    <li class="page-item"><a class="page-link" href="#">3</a></li>
    <li class="page-item">
      <a class="page-link" href="#">Next</a>

When should I use uuid.uuid1() vs. uuid.uuid4() in python?

My team just ran into trouble using UUID1 for a database upgrade script where we generated ~120k UUIDs within a couple of minutes. The UUID collision led to violation of a primary key constraint.

We've upgraded 100s of servers but on our Amazon EC2 instances we ran into this issue a few times. I suspect poor clock resolution and switching to UUID4 solved it for us.

What is the default access specifier in Java?

default is a keyword that is used as an access modifier for methods and variables.
Using this access modifier will make your class, variable, method or constructor acessible from own class or package, it will be also is set if no access modifier is present.

  Access Levels
    Modifier    Class   Package Subclass  EveryWhere
    public        Y        Y       Y         Y
    protected     Y        Y       Y         N
    default       Y        Y       N         N
    private       Y        N       N         N

if you use a default in a interface you will be able to implement a method there like this exemple

public interface Computer {    
    default void Start() {
        throw new UnsupportedOperationException("Error");

However it will only works from the 8 Java version

Official Documentation

Access Modifiers in Java

Regex replace (in Python) - a simpler way?

The short version is that you cannot use variable-width patterns in lookbehinds using Python's re module. There is no way to change this:

>>> import re
>>> re.sub("(?<=foo)bar(?=baz)", "quux", "foobarbaz")
>>> re.sub("(?<=fo+)bar(?=baz)", "quux", "foobarbaz")

Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    re.sub("(?<=fo+)bar(?=baz)", "quux", string)
  File "C:\Development\Python25\lib\", line 150, in sub
    return _compile(pattern, 0).sub(repl, string, count)
  File "C:\Development\Python25\lib\", line 241, in _compile
    raise error, v # invalid expression
error: look-behind requires fixed-width pattern

This means that you'll need to work around it, the simplest solution being very similar to what you're doing now:

>>> re.sub("(fo+)bar(?=baz)", "\\1quux", "foobarbaz")
>>> # If you need to turn this into a callable function:
>>> def replace(start, replace, end, replacement, search):
        return re.sub("(" + re.escape(start) + ")" + re.escape(replace) + "(?=" + re.escape + ")", "\\1" + re.escape(replacement), search)

This doesn't have the elegance of the lookbehind solution, but it's still a very clear, straightforward one-liner. And if you look at what an expert has to say on the matter (he's talking about JavaScript, which lacks lookbehinds entirely, but many of the principles are the same), you'll see that his simplest solution looks a lot like this one.

WordPress is giving me 404 page not found for all pages except the homepage

I had this issue not so long ago. I had reset my permalink to default or just saved it, updated themes/core to (4.7.4)/plugins, deactivated all plugins, switched to default theme, optimized database, .htaccess is already default, checked file permissions, mod_rewrite is on.

So far nothing works, what works are the posts, new page, the /contact page EXCEPT for old pages.

Basically, the pages/URLs that aren't working are:


Ultimate, I found these files in the root folder:

/breeding.php and /training.php

I renamed both files and the pages above worked.

Can I delete data from the iOS DeviceSupport directory?

Yes, you can delete data from iOS device support by the symbols of the operating system, one for each version for each architecture. It's used for debugging. If you don't need to support those devices any more, you can delete the directory without ill effect

How to update large table with millions of rows in SQL Server?

I want share my experience. A few days ago I have to update 21 million records in table with 76 million records. My colleague suggested the next variant. For example, we have the next table 'Persons':

Id | FirstName | LastName | Email            | JobTitle
1  | John      |  Doe     | [email protected]     | Software Developer
2  | John1     |  Doe1    | [email protected]     | Software Developer
3  | John2     |  Doe2    | [email protected]     | Web Designer

Task: Update persons to the new Job Title: 'Software Developer' -> 'Web Developer'.

1. Create Temporary Table 'Persons_SoftwareDeveloper_To_WebDeveloper (Id INT Primary Key)'

2. Select into temporary table persons which you want to update with the new Job Title:

INSERT INTO Persons_SoftwareDeveloper_To_WebDeveloper SELECT Id FROM
Persons WITH(NOLOCK) --avoid lock 
WHERE JobTitle = 'Software Developer' 
OPTION(MAXDOP 1) -- use only one core

Depends on rows count, this statement will take some time to fill your temporary table, but it would avoid locks. In my situation it took about 5 minutes (21 million rows).

3. The main idea is to generate micro sql statements to update database. So, let's print them:

DECLARE @i INT, @pagesize INT, @totalPersons INT
    SET @i=0
    SET @pagesize=2000
    SELECT @totalPersons = MAX(Id) FROM Persons

    while @i<= @totalPersons
    Print '
    UPDATE persons 
      SET persons.JobTitle = ''ASP.NET Developer''
      FROM  Persons_SoftwareDeveloper_To_WebDeveloper tmp
      JOIN Persons persons ON tmp.Id = persons.Id
      where persons.Id between '+cast(@i as varchar(20)) +' and '+cast(@i+@pagesize as varchar(20)) +' 
        PRINT ''Page ' + cast((@i / @pageSize) as varchar(20))  + ' of ' + cast(@totalPersons/@pageSize as varchar(20))+'
     set @i=@i+@pagesize

After executing this script you will receive hundreds of batches which you can execute in one tab of MS SQL Management Studio.

4. Run printed sql statements and check for locks on table. You always can stop process and play with @pageSize to speed up or speed down updating(don't forget to change @i after you pause script).

5. Drop Persons_SoftwareDeveloper_To_AspNetDeveloper. Remove temporary table.

Minor Note: This migration could take a time and new rows with invalid data could be inserted during migration. So, firstly fix places where your rows adds. In my situation I fixed UI, 'Software Developer' -> 'Web Developer'.

How can I use std::maps with user-defined types as key?

You need to define operator < for the Class1.

Map needs to compare the values using operator < and hence you need to provide the same when user defined class are used as key.

class Class1
    Class1(int id);

    bool operator <(const Class1& rhs) const
        return id <;
    int id;

Selenium Web Driver & Java. Element is not clickable at point (x, y). Other element would receive the click

If element is not clickable and overlay issue is ocuring we use arguments[0].click().

WebElement ele = driver.findElement(By.xpath("//div[@class='input-group-btn']/input")); JavascriptExecutor executor = (JavascriptExecutor)driver; executor.executeScript("arguments[0].click();", ele);

How do I choose grid and block dimensions for CUDA kernels?

The answers above point out how the block size can impact performance and suggest a common heuristic for its choice based on occupancy maximization. Without wanting to provide the criterion to choose the block size, it would be worth mentioning that CUDA 6.5 (now in Release Candidate version) includes several new runtime functions to aid in occupancy calculations and launch configuration, see

CUDA Pro Tip: Occupancy API Simplifies Launch Configuration

One of the useful functions is cudaOccupancyMaxPotentialBlockSize which heuristically calculates a block size that achieves the maximum occupancy. The values provided by that function could be then used as the starting point of a manual optimization of the launch parameters. Below is a little example.

#include <stdio.h>

__global__ void MyKernel(int *a, int *b, int *c, int N) 
    int idx = threadIdx.x + blockIdx.x * blockDim.x; 

    if (idx < N) { c[idx] = a[idx] + b[idx]; } 

/* MAIN */
void main() 
    const int N = 1000000;

    int blockSize;      // The launch configurator returned block size 
    int minGridSize;    // The minimum grid size needed to achieve the maximum occupancy for a full device launch 
    int gridSize;       // The actual grid size needed, based on input size 

    int* h_vec1 = (int*) malloc(N*sizeof(int));
    int* h_vec2 = (int*) malloc(N*sizeof(int));
    int* h_vec3 = (int*) malloc(N*sizeof(int));
    int* h_vec4 = (int*) malloc(N*sizeof(int));

    int* d_vec1; cudaMalloc((void**)&d_vec1, N*sizeof(int));
    int* d_vec2; cudaMalloc((void**)&d_vec2, N*sizeof(int));
    int* d_vec3; cudaMalloc((void**)&d_vec3, N*sizeof(int));

    for (int i=0; i<N; i++) {
        h_vec1[i] = 10;
        h_vec2[i] = 20;
        h_vec4[i] = h_vec1[i] + h_vec2[i];

    cudaMemcpy(d_vec1, h_vec1, N*sizeof(int), cudaMemcpyHostToDevice);
    cudaMemcpy(d_vec2, h_vec2, N*sizeof(int), cudaMemcpyHostToDevice);

    float time;
    cudaEvent_t start, stop;
    cudaEventRecord(start, 0);

    cudaOccupancyMaxPotentialBlockSize(&minGridSize, &blockSize, MyKernel, 0, N); 

    // Round up according to array size 
    gridSize = (N + blockSize - 1) / blockSize; 

    cudaEventRecord(stop, 0);
    cudaEventElapsedTime(&time, start, stop);
    printf("Occupancy calculator elapsed time:  %3.3f ms \n", time);

    cudaEventRecord(start, 0);

    MyKernel<<<gridSize, blockSize>>>(d_vec1, d_vec2, d_vec3, N); 

    cudaEventRecord(stop, 0);
    cudaEventElapsedTime(&time, start, stop);
    printf("Kernel elapsed time:  %3.3f ms \n", time);

    printf("Blocksize %i\n", blockSize);

    cudaMemcpy(h_vec3, d_vec3, N*sizeof(int), cudaMemcpyDeviceToHost);

    for (int i=0; i<N; i++) {
        if (h_vec3[i] != h_vec4[i]) { printf("Error at i = %i! Host = %i; Device = %i\n", i, h_vec4[i], h_vec3[i]); return; };

    printf("Test passed\n");



The cudaOccupancyMaxPotentialBlockSize is defined in the cuda_runtime.h file and is defined as follows:

template<class T>
__inline__ __host__ CUDART_DEVICE cudaError_t cudaOccupancyMaxPotentialBlockSize(
    int    *minGridSize,
    int    *blockSize,
    T       func,
    size_t  dynamicSMemSize = 0,
    int     blockSizeLimit = 0)
    return cudaOccupancyMaxPotentialBlockSizeVariableSMem(minGridSize, blockSize, func, __cudaOccupancyB2DHelper(dynamicSMemSize), blockSizeLimit);

The meanings for the parameters is the following

minGridSize     = Suggested min grid size to achieve a full machine launch.
blockSize       = Suggested block size to achieve maximum occupancy.
func            = Kernel function.
dynamicSMemSize = Size of dynamically allocated shared memory. Of course, it is known at runtime before any kernel launch. The size of the statically allocated shared memory is not needed as it is inferred by the properties of func.
blockSizeLimit  = Maximum size for each block. In the case of 1D kernels, it can coincide with the number of input elements.

Note that, as of CUDA 6.5, one needs to compute one's own 2D/3D block dimensions from the 1D block size suggested by the API.

Note also that the CUDA driver API contains functionally equivalent APIs for occupancy calculation, so it is possible to use cuOccupancyMaxPotentialBlockSize in driver API code in the same way shown for the runtime API in the example above.

Oracle JDBC ojdbc6 Jar as a Maven Dependency

Below config worked for me. Refer this link for more details.


Http Post request with content type application/x-www-form-urlencoded not working in Spring

The problem is that when we use application/x-www-form-urlencoded, Spring doesn't understand it as a RequestBody. So, if we want to use this we must remove the @RequestBody annotation.

Then try the following:

@RequestMapping(value = "/patientdetails", method = RequestMethod.POST,consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
public @ResponseBody List<PatientProfileDto> getPatientDetails(
        PatientProfileDto name) {

    List<PatientProfileDto> list = new ArrayList<PatientProfileDto>();
    list = service.getPatient(name);
    return list;

Note that removed the annotation @RequestBody

Advantages of SQL Server 2008 over SQL Server 2005?

SQL Server 2008 introduces four new date and time data types, which include:

* DATE: As you can imagine, the DATE data type only stores a date in the format of YYYY-MM-DD. It has a range of 0001-01-01 through 9999-12-32, which should be adequate for most business and scientific applications. The accuracy is 1 day, and it only takes 3 bytes to store the date.
* TIME: TIME is stored in the format: hh:mm:ss.nnnnnnn, with a range of 00:00:00.0000000 through 23:59:59:9999999 and is accurate to 100 nanoseconds. Storage depends on the precision and scale selected, and runs from 3 to 5 bytes.
* DATETIME2: DATETIME2 is very similar to the older DATETIME data type, but has a greater range and precision. The format is YYYY-MM-DD hh:mm:ss:nnnnnnnm with a range of 0001-01-01 00:00:00.0000000 through 9999-12-31 23:59:59.9999999, and an accuracy of 100 nanoseconds. Storage depends on the precision and scale selected, and runs from 6 to 8 bytes.
* DATETIMEOFFSET: DATETIMEOFFSET is similar to DATETIME2, but includes additional information to track the time zone. The format is YYYY-MM-DD hh:mm:ss[.nnnnnnn] [+|-]hh:mm with a range of 0001-01-01 00:00:00.0000000 through 0001-01-01 00:00:00.0000000 through 9999-12-31 23:59:59.9999999 (in UTC), and an accuracy of 100 nanoseconds. Storage depends on the precision and scale selected, and runs from 8 to 10 bytes.

Oracle TNS names not showing when adding new connection to SQL Developer

SQL Developer will look in the following location in this order for a tnsnames.ora file

  1. $HOME/.tnsnames.ora
  2. $TNS_ADMIN/tnsnames.ora
  3. TNS_ADMIN lookup key in the registry
  4. /etc/tnsnames.ora ( non-windows )
  5. $ORACLE_HOME/network/admin/tnsnames.ora

To see which one SQL Developer is using, issue the command show tns in the worksheet

If your tnsnames.ora file is not getting recognized, use the following procedure:

  1. Define an environmental variable called TNS_ADMIN to point to the folder that contains your tnsnames.ora file.

    In Windows, this is done by navigating to Control Panel > System > Advanced system settings > Environment Variables...

    In Linux, define the TNS_ADMIN variable in the .profile file in your home directory.

  2. Confirm the os is recognizing this environmental variable

    From the Windows command line: echo %TNS_ADMIN%

    From linux: echo $TNS_ADMIN

  3. Restart SQL Developer

  4. Now in SQL Developer right click on Connections and select New Connection.... Select TNS as connection type in the drop down box. Your entries from tnsnames.ora should now display here.

Groovy - Convert object to JSON string

You can use JsonBuilder for that.

Example Code:

import groovy.json.JsonBuilder

class Person {
    String name
    String address

def o = new Person( name: 'John Doe', address: 'Texas' )

println new JsonBuilder( o ).toPrettyString()

Pass a reference to DOM object with ng-click

The angular way is shown in the angular docs :)

Here is the example they use:

    Check me to make text readonly: <input type="checkbox" ng-model="checked"><br/>
    <input type="text" ng-readonly="checked" value="I'm Angular"/>

Basically the angular way is to create a model object that will hold whether or not the input should be readonly and then set that model object accordingly. The beauty of angular is that most of the time you don't need to do any dom manipulation. You just have angular render the view they way your model is set (let angular do the dom manipulation for you and keep your code clean).

So basically in your case you would want to do something like below or check out this working example.

<button ng-click="isInput1ReadOnly = !isInput1ReadOnly">Click Me</button>
<input type="text" ng-readonly="isInput1ReadOnly" value="Angular Rules!"/>

Differences between Html.TextboxFor and Html.EditorFor in MVC and Razor

TextBoxFor: It will render like text input html element corresponding to specified expression. In simple word it will always render like an input textbox irrespective datatype of the property which is getting bind with the control.

EditorFor: This control is bit smart. It renders HTML markup based on the datatype of the property. E.g. suppose there is a boolean property in model. To render this property in the view as a checkbox either we can use CheckBoxFor or EditorFor. Both will be generate the same markup.

What is the advantage of using EditorFor?

As we know, depending on the datatype of the property it generates the html markup. So suppose tomorrow if we change the datatype of property in the model, no need to change anything in the view. EditorFor control will change the html markup automatically.

Using Ajax.BeginForm with ASP.NET MVC 3 Razor

I think that all the answers missed a crucial point:

If you use the Ajax form so that it needs to update itself (and NOT another div outside of the form) then you need to put the containing div OUTSIDE of the form. For example:

 <div id="target">
 @using (Ajax.BeginForm("MyAction", "MyController",
            new AjaxOptions
                HttpMethod = "POST",
                InsertionMode = InsertionMode.Replace,
                UpdateTargetId = "target"
      <!-- whatever -->

Otherwise you will end like @David where the result is displayed in a new page.

How do I get the value of a registry key and ONLY the value using powershell

Given a key \SQL with two properties:

enter image description here

I'd grab the "MSSQLSERVER" one with the following in-cases where I wasn't sure what the property name was going to be to use dot-notation:

$regkey_property_name = 'MSSQLSERVER'
$regkey = get-item -Path 'HKLM:\Software\Microsoft\Microsoft SQL Server\Instance Names\SQL'

Remove last item from array

learn by example:

let array_1 = [1,2,3,4];
let array_2 = [1,2,3,4];
let array_3 = [1,2,3,4];

array_1.splice(-1,1)  // output --> [4]      array_1 = [1,2,3]
array_2.slice(0,-1);  // output --> [1,2,3]  array_2 = [1,2,3,4]
array_3.pop();        // output --> 4        array_3 = [1,2,3]

SSIS Text was truncated with status value 4

If all other options have failed, trying recreating the data import task and/or the connection manager. If you've made any changes since the task was originally created, this can sometimes do the trick. I know it's the equivalent of rebooting, but, hey, if it works, it works.

Open two instances of a file in a single Visual Studio session

Window menu, New Horizontal/Vertical Tab Group there will do, I think.

how to add <script>alert('test');</script> inside a text box?

is you want fix XSS on input element? you can encode string before output to input field


$str = htmlentities($str);


str = WebUtility.HtmlEncode(str);

after that output value direct to input field:

<input type="text" value="<?php echo $str" />

HTML-Tooltip position relative to mouse pointer

This CAN be done with pure html and css. It may not be the best way but we all have different limitations. There are 3 ways that could be useful depending on what your specific circumstances are.

  1. The first involves overlaying an invisible table over top of your link with a hover action on each cell that displays an image.

#imagehover td:hover::after{_x000D_
  content: "             ";_x000D_
  white-space: pre;_x000D_
  background-image: url("");_x000D_
  position: relative;_x000D_
  left: 5px;_x000D_
  top: 5px;_x000D_
  font-size: 20px;_x000D_
  background-color: transparent;_x000D_
  background-position: 0px 0px;_x000D_
  background-size: 60px 20px;_x000D_
  background-repeat: no-repeat;_x000D_
#imagehover table, #imagehover th, #imagehover td {_x000D_
  border: 0px;_x000D_
  border-spacing: 0px;_x000D_
<a href="">_x000D_
<table id="imagehover" style="width:50px;height:10px;z-index:9999;position:absolute" cellspacing="0">_x000D_

  1. The second relies on being able to create your own cursor image

cursor: url(,url(,auto;_x000D_
<a href="" id="googleLink">Google</a>

  1. While the normal title tooltip doesn't technically allow images it does allow any unicode characters including block letters and emojis which may suite your needs.

<a href="" title="??" alt="??">Google</a>

Can't check signature: public key not found

There is a similar is a tomcat digital signature.

$ gpg --verify apache-tomcat-9.0.16-windows-
gpg: Signature made 2019?02? 5?  0:32:50
gpg:                using RSA key A9C5DF4D22E99998D9875A5110C01C5A2F6059E7
gpg: Can't check signature: No public key

but then I use the RSA key it provided to receive the public key to verify.

$ gpg --receive-keys A9C5DF4D22E99998D9875A5110C01C5A2F6059E7
gpg: key 10C01C5A2F6059E7: 38 signatures not checked due to missing keys
gpg: key 10C01C5A2F6059E7: public key "Mark E D Thomas <[email protected]>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1

Then successfully.

$ gpg --verify
gpg: assuming signed data in ''
gpg: Signature made 2019?02? 5?  0:32:50
gpg:                using RSA key A9C5DF4D22E99998D9875A5110C01C5A2F6059E7
gpg: Good signature from "Mark E D Thomas <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: A9C5 DF4D 22E9 9998 D987  5A51 10C0 1C5A 2F60 59E7

What does Python's socket.recv() return for non-blocking sockets if no data is received until a timeout occurs?

When you use recv in connection with select if the socket is ready to be read from but there is no data to read that means the client has closed the connection.

Here is some code that handles this, also note the exception that is thrown when recv is called a second time in the while loop. If there is nothing left to read this exception will be thrown it doesn't mean the client has closed the connection :

def listenToSockets(self):

    while True:

        changed_sockets = self.currentSockets

        ready_to_read, ready_to_write, in_error =, [], [], 0.1)

        for s in ready_to_read:

            if s == self.serverSocket:

And the function that receives the data :

def readDataFromSocket(self, socket):

    data = ''
    buffer = ''

        while True:
            data = socket.recv(4096)

            if not data: 

            buffer += data

    except error, (errorCode,message): 
        # error 10035 is no data available, it is non-fatal
        if errorCode != 10035:
            print 'socket.error - ('+str(errorCode)+') ' + message

    if data:
        print 'received '+ buffer
        print 'disconnected'

Recommended way to get hostname in Java

Just one-liner ... cross platform (Windows-Linux-Unix-Mac(Unix)) [Always works, No DNS required]:

String hostname = new BufferedReader(
    new InputStreamReader(Runtime.getRuntime().exec("hostname").getInputStream()))

You're done !!

How to concatenate two layers in keras?

Adding to the above-accepted answer so that it helps those who are using tensorflow 2.0

import tensorflow as tf

# some data
c1 = tf.constant([[1, 1, 1], [2, 2, 2]], dtype=tf.float32)
c2 = tf.constant([[2, 2, 2], [3, 3, 3]], dtype=tf.float32)
c3 = tf.constant([[3, 3, 3], [4, 4, 4]], dtype=tf.float32)

# bake layers x1, x2, x3
x1 = tf.keras.layers.Dense(10)(c1)
x2 = tf.keras.layers.Dense(10)(c2)
x3 = tf.keras.layers.Dense(10)(c3)

# merged layer y1
y1 = tf.keras.layers.Concatenate(axis=1)([x1, x2])

# merged layer y2
y2 = tf.keras.layers.Concatenate(axis=1)([y1, x3])

# print info
print("x1", x1.shape, "x2", x2.shape, "x3", x3.shape)
print("y1", y1.shape)
print("y2", y2.shape)


x1 (2, 10) x2 (2, 10) x3 (2, 10)
y1 (2, 20)
y2 (2, 30)

How do you get the magnitude of a vector in Numpy?

The function you're after is numpy.linalg.norm. (I reckon it should be in base numpy as a property of an array -- say x.norm() -- but oh well).

import numpy as np
x = np.array([1,2,3,4,5])

You can also feed in an optional ord for the nth order norm you want. Say you wanted the 1-norm:


And so on.

How do I find the duplicates in a list and create another list with them?

I do not see a solution that is purely using iterators, so here we go

This requires the list to be sorted, which may be the drawback here.

a = [1,2,3,2,1,5,6,5,5,5]
set(map(lambda x: x[0], filter(lambda x: x[0] == x[1], zip(a, a[1:]))))

{1, 2, 5}

You can easily check how fast this is on your machine with a million potential duplicates with this piece of code:

First generate the data

import random
from itertools import chain
a = list(chain(*[[n] * random.randint(1, 2) for n in range(1000000)]))

And run the test:

set(map(lambda x: x[0], filter(lambda x: x[0] == x[1], zip(a, a[1:]))))

Needless to say, this solution is only good if your list is already sorted.

Can't execute jar- file: "no main manifest attribute"

Found a great solution which would help in any such situation, given you just need a runnable jar, which you do in most cases. If your application is running in Intellij Idea follow these steps: 1) Go to module settings and then artifacts, and add a jar and define main class 2) Then go to Build in the menu and click "build artifact" and you get the jar.

This worked even when I changed the source folder and used scala instead of java.

How can I make a menubar fixed on the top while scrolling

This should get you started

 <div class="menuBar">
        <img class="logo" src="logo.jpg"/>
        <div class="nav"> 
                <li>Menu 2</li>
                <li>Menu 3</li>

.nav ul li{

using setTimeout on promise chain

In node.js you can also do the following:

const { promisify } = require('util')
const delay = promisify(setTimeout)

delay(1000).then(() => console.log('hello'))

What is a good naming convention for vars, methods, etc in C++?

consistency and readability (self-documenting code) are important. some clues (such as case) can and should be used to avoid collisions, and to indicate whether an instance is required.

one of the best practices i got into was the use of code formatters (astyle and uncrustify are 2 examples). code formatters can destroy your code formatting - configure the formatter, and let it do its job. seriously, forget about manual formatting and get into the practice of using them. they will save a ton of time.

as mentioned, be very descriptive with naming. also, be very specific with scoping (class types/data/namespaces/anonymous namespaces). in general, i really like much of java's common written form - that is a good reference and similar to c++.

as for specific appearance/naming, this is a small sample similar to what i use (variables/arguments are lowerCamel and this only demonstrates a portion of the language's features):

/** MYC_BEGIN_FILE_ID::FD_Directory_nanotimer_FN_nanotimer_hpp_::MYC_BEGIN_FILE_DIR::Directory/nanotimer::MYC_BEGIN_FILE_FILE::nanotimer.hpp::Copyright... */
#ifndef FD_Directory_nanotimer_FN_nanotimer_hpp_
#define FD_Directory_nanotimer_FN_nanotimer_hpp_

/* typical commentary omitted -- comments detail notations/conventions. also, no defines/macros other than header guards */

namespace NamespaceName {

/* types prefixed with 't_' */
class t_nanotimer : public t_base_timer {
    /* private types */
    class t_thing {
    /* public types */
    typedef uint64_t t_nanosecond;

    /* factory initializers -- UpperCamel */
    t_nanotimer* WithFloat(const float& arg);
    /* public/protected class interface -- UpperCamel */
    static float Uptime();
    /* static class data -- UpperCamel -- accessors, if needed, use Get/Set prefix */
    static const t_spoke Spoke;
    /* enums in interface are labeled as static class data */
    enum { Granularity = 4 };
    /* construction/destruction -- always use proper initialization list */
    explicit t_nanotimer(t_init);
    explicit t_nanotimer(const float& arg);

    virtual ~t_nanotimer();

       public and protected instance methods -- lowercaseCamel()
       - booleans prefer is/has
       - accessors use the form: getVariable() setVariable().
       const-correctness is important
    const void* address() const;
    virtual uint64_t hashCode() const;
    /* interfaces/implementation of base pure virtuals (assume this was pure virtual in t_base_timer) */
    virtual bool hasExpired() const;
    /* private methods and private static data */
    void invalidate();
       instance variables
       - i tend to use underscore suffix, but d_ (for example) is another good alternative
       - note redundancy in visibility
    t_thing ivar_;
    /* prohibited stuff */
    explicit t_nanotimer();
    explicit t_nanotimer(const int&);
} /* << NamespaceName */
/* i often add a multiple include else block here, preferring package-style inclusions */    
#endif /* MYC_END_FILE::FD_Directory_nanotimer_FN_nanotimer_hpp_ */

module.exports vs exports in Node.js

Let's create one module with 2 ways:

One way

var aa = {
    a: () => {return 'a'},
    b: () => {return 'b'}

module.exports = aa;

Second way

exports.a = () => {return 'a';}
exports.b = () => {return 'b';}

And this is how require() will integrate module.

First way:

function require(){
    module.exports = {};
    var exports = module.exports;

    var aa = {
        a: () => {return 'a'},
        b: () => {return 'b'}
    module.exports = aa;

    return module.exports;

Second way

function require(){
    module.exports = {};
    var exports = module.exports;

    exports.a = () => {return 'a';}
    exports.b = () => {return 'b';}

    return module.exports;

Sql Server equivalent of a COUNTIF aggregate function

SELECT COALESCE(IF(myColumn = 1,COUNT(DISTINCT NumberColumn),NULL),0) column1,
FROM AD_CurrentView

Finding duplicate values in MySQL

I prefer to use windowed functions(MySQL 8.0+) to find duplicates because I could see entire row:

WITH cte AS (
    ,COUNT(*) OVER(PARTITION BY col_name) AS num_of_duplicates_group
    ,ROW_NUMBER() OVER(PARTITION BY col_name ORDER BY col_name2) AS pos_in_group
  FROM table
FROM cte
WHERE num_of_duplicates_group > 1;

DB Fiddle Demo

Pass a datetime from javascript to c# (Controller)

try this

var date = new Date();    
       type: "POST",
       url: "/Group/Refresh",
       contentType: "application/json; charset=utf-8",
       data: "{ 'MyDate': " + date.getTimezoneOffset() + " }",
       success: function (result) {
           //do something
       error: function (req, status, error) {

In C#


Warning as error - How to get rid of these

VS 2019

Just for people using VS2019, I think other answers are also pointing out same location.

Select All as default value for Multivalue parameter

Adding to the answer from E_8.
This does not work if you have empty strings.

You can get around this by modifying your select statement in SQL or modifying your query in the SSRS dataset.

 Select distinct phonenumber
from YourTable
where phonenumber <> ''
Order by Phonenumber

Python - How to convert JSON File to Dataframe

import pandas as pd

This will Normalize semi-structured JSON data into a flat table


  FirstName LastName MiddleName password    username
      John     Mark      Lewis     2910  johnlewis2

How do I force files to open in the browser instead of downloading (PDF)?

To indicate to the browser that the file should be viewed in the browser, the HTTP response should include these headers:

Content-Type: application/pdf
Content-Disposition: inline; filename="filename.pdf"

To have the file downloaded rather than viewed:

Content-Type: application/pdf
Content-Disposition: attachment; filename="filename.pdf"

The quotes around the filename are required if the filename contains special characters such as filename[1].pdf which may otherwise break the browser's ability to handle the response.

How you set the HTTP response headers will depend on your HTTP server (or, if you are generating the PDF response from server-side code: your server-side programming language).

Get value from hidden field using jQuery

var hiddenFieldID = "input[id$=" + hiddenField + "]";
var requiredVal= $(hiddenFieldID).val();

Returning a regex match in VBA (excel)

You need to access the matches in order to get at the SDI number. Here is a function that will do it (assuming there is only 1 SDI number per cell).

For the regex, I used "sdi followed by a space and one or more numbers". You had "sdi followed by a space and zero or more numbers". You can simply change the + to * in my pattern to go back to what you had.

Function ExtractSDI(ByVal text As String) As String

Dim result As String
Dim allMatches As Object
Dim RE As Object
Set RE = CreateObject("vbscript.regexp")

RE.pattern = "(sdi \d+)"
RE.Global = True
RE.IgnoreCase = True
Set allMatches = RE.Execute(text)

If allMatches.count <> 0 Then
    result = allMatches.Item(0).submatches.Item(0)
End If

ExtractSDI = result

End Function

If a cell may have more than one SDI number you want to extract, here is my RegexExtract function. You can pass in a third paramter to seperate each match (like comma-seperate them), and you manually enter the pattern in the actual function call:

Ex) =RegexExtract(A1, "(sdi \d+)", ", ")

Here is:

Function RegexExtract(ByVal text As String, _
                      ByVal extract_what As String, _
                      Optional seperator As String = "") As String

Dim i As Long, j As Long
Dim result As String
Dim allMatches As Object
Dim RE As Object
Set RE = CreateObject("vbscript.regexp")

RE.pattern = extract_what
RE.Global = True
Set allMatches = RE.Execute(text)

For i = 0 To allMatches.count - 1
    For j = 0 To allMatches.Item(i).submatches.count - 1
        result = result & seperator & allMatches.Item(i).submatches.Item(j)

If Len(result) <> 0 Then
    result = Right(result, Len(result) - Len(seperator))
End If

RegexExtract = result

End Function

*Please note that I have taken "RE.IgnoreCase = True" out of my RegexExtract, but you could add it back in, or even add it as an optional 4th parameter if you like.

Jquery Date picker Default Date

$( ".selector" ).datepicker({ defaultDate: null });

and return empty string from backend

How to record phone calls in android?

Ok, for this first of all you need to use Device Policy Manager, and need to make your device Admin device. After that you have to create one BroadCast receiver and one service. I am posting code here and its working fine.


public class MainActivity extends Activity {
    private static final int REQUEST_CODE = 0;
    private DevicePolicyManager mDPM;
    private ComponentName mAdminName;

    protected void onCreate(Bundle savedInstanceState) {

        try {
            // Initiate DevicePolicyManager.
            mDPM = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
            mAdminName = new ComponentName(this, DeviceAdminDemo.class);

            if (!mDPM.isAdminActive(mAdminName)) {
                Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
                intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mAdminName);
                intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "Click on Activate button to secure your application.");
                startActivityForResult(intent, REQUEST_CODE);
            } else {
                // mDPM.lockNow();
                // Intent intent = new Intent(MainActivity.this,
                // TrackDeviceService.class);
                // startService(intent);
        } catch (Exception e) {

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (REQUEST_CODE == requestCode) {
                Intent intent = new Intent(MainActivity.this, TService.class);


//DeviceAdminDemo class

public class DeviceAdminDemo extends DeviceAdminReceiver {
    public void onReceive(Context context, Intent intent) {
        super.onReceive(context, intent);

    public void onEnabled(Context context, Intent intent) {

    public void onDisabled(Context context, Intent intent) {

//TService Class

public class TService extends Service {
    MediaRecorder recorder;
    File audiofile;
    String name, phonenumber;
    String audio_format;
    public String Audio_Type;
    int audioSource;
    Context context;
    private Handler handler;
    Timer timer;
    Boolean offHook = false, ringing = false;
    Toast toast;
    Boolean isOffHook = false;
    private boolean recordstarted = false;

    private static final String ACTION_IN = "android.intent.action.PHONE_STATE";
    private static final String ACTION_OUT = "android.intent.action.NEW_OUTGOING_CALL";
    private CallBr br_call;

    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;

    public void onDestroy() {
        Log.d("service", "destroy");


    public int onStartCommand(Intent intent, int flags, int startId) {
        // final String terminate =(String)
        // intent.getExtras().get("terminate");//
        // intent.getStringExtra("terminate");
        // Log.d("TAG", "service started");
        // TelephonyManager telephony = (TelephonyManager)
        // getSystemService(Context.TELEPHONY_SERVICE); // TelephonyManager
        // // object
        // CustomPhoneStateListener customPhoneListener = new
        // CustomPhoneStateListener();
        // telephony.listen(customPhoneListener,
        // PhoneStateListener.LISTEN_CALL_STATE);
        // context = getApplicationContext();

        final IntentFilter filter = new IntentFilter();
        this.br_call = new CallBr();
        this.registerReceiver(this.br_call, filter);

        // if(terminate != null) {
        // stopSelf();
        // }
        return START_NOT_STICKY;

    public class CallBr extends BroadcastReceiver {
        Bundle bundle;
        String state;
        String inCall, outCall;
        public boolean wasRinging = false;

        public void onReceive(Context context, Intent intent) {
            if (intent.getAction().equals(ACTION_IN)) {
                if ((bundle = intent.getExtras()) != null) {
                    state = bundle.getString(TelephonyManager.EXTRA_STATE);
                    if (state.equals(TelephonyManager.EXTRA_STATE_RINGING)) {
                        inCall = bundle.getString(TelephonyManager.EXTRA_INCOMING_NUMBER);
                        wasRinging = true;
                        Toast.makeText(context, "IN : " + inCall, Toast.LENGTH_LONG).show();
                    } else if (state.equals(TelephonyManager.EXTRA_STATE_OFFHOOK)) {
                        if (wasRinging == true) {

                            Toast.makeText(context, "ANSWERED", Toast.LENGTH_LONG).show();

                            String out = new SimpleDateFormat("dd-MM-yyyy hh-mm-ss").format(new Date());
                            File sampleDir = new File(Environment.getExternalStorageDirectory(), "/TestRecordingDasa1");
                            if (!sampleDir.exists()) {
                            String file_name = "Record";
                            try {
                                audiofile = File.createTempFile(file_name, ".amr", sampleDir);
                            } catch (IOException e) {
                            String path = Environment.getExternalStorageDirectory().getAbsolutePath();

                            recorder = new MediaRecorder();
//                          recorder.setAudioSource(MediaRecorder.AudioSource.VOICE_CALL);

                            try {
                            } catch (IllegalStateException e) {
                            } catch (IOException e) { 
                            recordstarted = true;
                    } else if (state.equals(TelephonyManager.EXTRA_STATE_IDLE)) {
                        wasRinging = false;
                        Toast.makeText(context, "REJECT || DISCO", Toast.LENGTH_LONG).show();
                        if (recordstarted) {
                            recordstarted = false;
            } else if (intent.getAction().equals(ACTION_OUT)) {
                if ((bundle = intent.getExtras()) != null) {
                    outCall = intent.getStringExtra(Intent.EXTRA_PHONE_NUMBER);
                    Toast.makeText(context, "OUT : " + outCall, Toast.LENGTH_LONG).show();


//Permission in manifest file

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />
    <uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.STORAGE" />


<device-admin xmlns:android="" >
        <force-lock />

//Declare following thing in manifest:

Declare DeviceAdminDemo class to manifest:

            android:permission="android.permission.BIND_DEVICE_ADMIN" >
                android:resource="@xml/my_admin" />

                <action android:name="" />
                <action android:name="" />
                <action android:name="" />

<service android:name=".TService" >

deny directory listing with htaccess

Try adding this to the .htaccess file in that directory.

Options -Indexes

This has more information.

PostgreSQL: Drop PostgreSQL database through command line

This worked for me:

select pg_terminate_backend(pid) from pg_stat_activity where datname='YourDatabase';

for postgresql earlier than 9.2 replace pid with procpid

DROP DATABASE "YourDatabase";

Python - Create list with numbers between 2 values?

In python you can do this very eaisly

output: arr=[0,1,2,3,4,5,6,7,8,9,10]

or you can create a recursive function that returns an array upto a given number:

def diff(start,end):
    if start==end:
        return ar
        return diff(start-1,end) 

output: ar=[10,9,8,7,6,5,4,3,2,1,0]

Angular 4 checkbox change value

Give a try on this,


<input (change)="fieldsChange($event)" value="angular" type="checkbox"/>

Ts File

fieldsChange(values:any):void {

'str' object has no attribute 'decode'. Python 3 error?

It s already decoded in Python3, Try directly it should work.

How do I change the text of a span element using JavaScript?

Here's another way:

var myspan = document.getElementById('myspan');

if (myspan.innerText) {
    myspan.innerText = "newtext";
if (myspan.textContent) {
        myspan.textContent = "newtext";   

The innerText property will be detected by Safari, Google Chrome and MSIE. For Firefox, the standard way of doing things was to use textContent but since version 45 it too has an innerText property, as someone kindly apprised me recently. This solution tests to see if a browser supports either of these properties and if so, assigns the "newtext".

Live demo: here

jQuery .get error response function?

If you want a generic error you can setup all $.ajax() (which $.get() uses underneath) requests jQuery makes to display an error using $.ajaxSetup(), for example:

  error: function(xhr, status, error) {
    alert("An AJAX error occured: " + status + "\nError: " + error);

Just run this once before making any AJAX calls (no changes to your current code, just stick this before somewhere). This sets the error option to default to the handler/function above, if you made a full $.ajax() call and specified the error handler then what you had would override the above.

Request failed: unacceptable content-type: text/html using AFNetworking 2.0

On the server side, I added:

header('Content-type: application/json');

into my .php code and this also fixed the problem.

Nginx not picking up site in sites-enabled?

Include sites-available/default in sites-enabled/default. It requires only one line.

In sites-enabled/default (new config version?):

It seems that the include path is relative to the file that included it

include sites-available/default;

See the include documentation.

I believe that certain versions of nginx allows including/linking to other files purely by having a single line with the relative path to the included file. (At least that's what it looked like in some "inherited" config files I've been using, until a new nginx version broke them.)

In sites-enabled/default (old config version?):

It seems that the include path is relative to the current file


What is a "web service" in plain English?

An operating system provides a GUI (and CLI) that you can interact with. It also provides an API that you can interact with programmatically.

Similarly, a website provides HTML pages that you can interact with and may also provide an API that offers the same information and operations programmatically. Or those services may only be available via an API with no associated user interface.

How can I call a function using a function pointer?

Slightly different approach:

bool A() {...}
bool B() {...}
bool C() {...}

int main(void)
   * Declare an array of pointers to functions returning bool
   * and initialize with A, B, and C
  bool (*farr[])() = {A, B, C};
   * Call A, B, or C based on the value of i
   * (assumes i is in range of array)
  if (farr[i]()) // or (*farr[i])()

"Default Activity Not Found" on Android Studio upgrade

You Might be missing attributes. Make sure to include this activity inside manifest file

Convert Uppercase Letter to Lowercase and First Uppercase in Sentence using CSS

Use mixins

@mixin sentence-case() {_x000D_
  text-transform: lowercase;_x000D_
  &:first-letter {_x000D_
    text-transform: uppercase;_x000D_
// USAGE:_x000D_
.title {_x000D_
  @include sentence-case();_x000D_

Call to undefined function mysql_connect

One time I had a problem while using Off instead of off. And also check the pads one more time... The path has to be exact. Also add the following line to your environmental variable.

C:\your-apache-path\bin; C:\your-php-path\bin;C:\your-mysql-path\bin

If you are in Windows, right click My Computer, select properties, and navigate to the Advanced tab... (is Windows 7). Click on Advanced system settings first then select the Advanced tab and then Environmental variables. Select PATH and click on Edit. Make a copy of the string in a .txt file for back up (it might be empty)--- set your environmental variables... Log out and log back in.

Convert output of MySQL query to utf8

SELECT CONVERT(CAST(column as BINARY) USING utf8) as column FROM table 

How do I view Android application specific cache?

Question: Where is application-specific cache located on Android?

Answer: /data/data

SQLAlchemy IN clause

An alternative way is using raw SQL mode with SQLAlchemy, I use SQLAlchemy 0.9.8, python 2.7, MySQL 5.X, and MySQL-Python as connector, in this case, a tuple is needed. My code listed below:

id_list = [1, 2, 3, 4, 5] # in most case we have an integer list or set
s = text('SELECT id, content FROM myTable WHERE id IN :id_list')
conn = engine.connect() # get a mysql connection
rs = conn.execute(s, id_list=tuple(id_list)).fetchall()

Hope everything works for you.

Error: Unexpected value 'undefined' imported by the module

My problem was a misspelled component name inside the component.ts.

The import statement didn't show an error but the declaration did, which misled me.

Error handling with PHPMailer

In PHPMailer.php, there are lines as below:

echo $e->getMessage()

Just comment these lines and you will be good to go.

SQL WHERE condition is not equal to?

I was just solving this problem. If you use <> or is not in on a variable, that is null, it will result in false. So instead of <> 1, you must check it like this:

 AND (isdelete is NULL or isdelete = 0)

How to POST the data from a modal form of Bootstrap?

You need to handle it via ajax submit.

Something like this:

    $('#subscribe-email-form').on('submit', function(e){
            url: url, //this is the submit URL
            type: 'GET', //or POST
            data: $('#subscribe-email-form').serialize(),
            success: function(data){
                 alert('successfully submitted')

A better way would be to use a django form, and then render the following snippet:

    <div class="modal-body">
        <input type="email" placeholder="email"/>
        <p>This service will notify you by email should any issue arise that affects your plivo service.</p>
    <div class="modal-footer">
        <input type="submit" value="SUBMIT" class="btn"/>

via the context - example : {{form}}.

Getting Date or Time only from a DateTime Object

var day = value.Date; // a DateTime that will just be whole days
var time = value.TimeOfDay; // a TimeSpan that is the duration into the day

How to make a parent div auto size to the width of its children divs

The parent div (I assume the outermost div) is display: block and will fill up all available area of its container (in this case, the body) that it can. Use a different display type -- inline-block is probably what you are going for:

Swipe to Delete and the "More" button (like in Mail app on iOS 7)

This is (rather ridiculously) a private API.

The following two methods are private and sent to the UITableView's delegate:

-(NSString *)tableView:(UITableView *)tableView titleForSwipeAccessoryButtonForRowAtIndexPath:(NSIndexPath *)indexPath;
-(void)tableView:(UITableView *)tableView swipeAccessoryButtonPushedForRowAtIndexPath:(NSIndexPath *)indexPath;

They are pretty self explanatory.

Best way to convert an ArrayList to a string

For this simple use case, you can simply join the strings with comma. If you use Java 8:

String csv = String.join("\t", yourArray);

otherwise commons-lang has a join() method:

String csv = org.apache.commons.lang3.StringUtils.join(yourArray, "\t");

Why does visual studio 2012 not find my tests?

Tests do not like async methods. Eg:

    public async void TestMethod1()
        TestLib oLib = new TestLib();
        var bTest = await oLib.Authenticate();


After doing this:

    public void TestAuth()

    public async void TestMethod1()
        TestLib oLib = new TestLib();
        var bTest = await oLib.Authenticate();


It saw the test.

Matplotlib 2 Subplots, 1 Colorbar

Shared colormap and colorbar

This is for the more complex case where the values are not just between 0 and 1; the cmap needs to be shared instead of just using the last one.

import numpy as np
from matplotlib.colors import Normalize
import matplotlib.pyplot as plt
import as cm
fig, axes = plt.subplots(nrows=2, ncols=2)
for i,ax in enumerate(axes.flat):
fig.colorbar(im, ax=axes.ravel().tolist())

How do I limit the number of returned items?

models.Post.find({published: true}, {sort: {'date': -1}, limit: 20}, function(err, posts) {
 // `posts` with sorted length of 20

Why is Chrome showing a "Please Fill Out this Field" tooltip on empty fields?

If you have an html form containing one or more fields with "required" attributes, Chrome (on last versions) will validate these fields before submitting the form and, if they are not filled, some tooltips will be shown to the users to help them getting the form submitted (I.e. "please fill out this field").

To avoid this browser built-in validation in forms you can use "novalidate" attribute on your form tag. This form won't be validated by browser:

<form id="form-id" novalidate>

    <input id="input-id" type="text" required>

    <input id="submit-button" type="submit">


is of a type that is invalid for use as a key column in an index

A solution would be to declare your key as nvarchar(20).

How to read large text file on windows?

use EmEditor, it's pretty good, i used it to open a file with more than 500mb

Make body have 100% of the browser height

After testing various scenarios, I believe this is the best solution:

html {
    width: 100%;
    height: 100%;
    display: table;

body {
    width: 100%;
    display: table-cell;

html, body {
    margin: 0px;
    padding: 0px;

It is dynamic in that the html and the body elements will expand automatically if their contents overflow. I tested this in the latest version of Firefox, Chrome, and IE 11.

See the full fiddle here (for you table haters out there, you can always change it to use a div):

With that being said, there are several issues with the answers posted here.

html, body {
    height: 100%;

Using the above CSS will cause the html and the body element to NOT automatically expand if their contents overflow as shown here:

As you scroll, notice the repeating background? This is happening because the body element's height has NOT increased due to its child table overflowing. Why doesn't it expand like any other block element? I'm not sure. I think browsers handle this incorrectly.

html {
    height: 100%;

body {
    min-height: 100%;

Setting a min-height of 100% on the body as shown above causes other problems. If you do this, you cannot specify that a child div or table take up a percentage height as shown here:

Hope this helps someone. I think browsers are handling this incorrectly. I would expect the body's height to automatically adjust growing larger if its children overflow. However, that doesn't seem to happen when you use 100% height and 100% width.

How do I add an element to a list in Groovy?

From the documentation:

We can add to a list in many ways:

assert [1,2] + 3 + [4,5] + 6 == [1, 2, 3, 4, 5, 6]
assert [1,2].plus(3).plus([4,5]).plus(6) == [1, 2, 3, 4, 5, 6]
    //equivalent method for +
def a= [1,2,3]; a += 4; a += [5,6]; assert a == [1,2,3,4,5,6]
assert [1, *[222, 333], 456] == [1, 222, 333, 456]
assert [ *[1,2,3] ] == [1,2,3]
assert [ 1, [2,3,[4,5],6], 7, [8,9] ].flatten() == [1, 2, 3, 4, 5, 6, 7, 8, 9]

def list= [1,2]
list.add(3) //alternative method name
list.addAll([5,4]) //alternative method name
assert list == [1,2,3,5,4]

list= [1,2]
list.add(1,3) //add 3 just before index 1
assert list == [1,3,2]
list.addAll(2,[5,4]) //add [5,4] just before index 2
assert list == [1,3,5,4,2]

list = ['a', 'b', 'z', 'e', 'u', 'v', 'g']
list[8] = 'x'
assert list == ['a', 'b', 'z', 'e', 'u', 'v', 'g', null, 'x']

You can also do:

def myNewList = myList << "fifth"

boundingRectWithSize for NSAttributedString returning wrong size

Looks like you weren't providing the correct options. For wrapping labels, provide at least:

CGRect paragraphRect =
  [attributedText boundingRectWithSize:CGSizeMake(300.f, CGFLOAT_MAX)

Note: if the original text width is under 300.f there won't be line wrapping, so make sure the bound size is correct, otherwise you will still get wrong results.

Why a function checking if a string is empty always returns true?

Simple problem actually. Change:

if (strTemp != '')


if ($strTemp != '')

Arguably you may also want to change it to:

if ($strTemp !== '')

since != '' will return true if you pass is numeric 0 and a few other cases due to PHP's automatic type conversion.

You should not use the built-in empty() function for this; see comments and the PHP type comparison tables.

Spring Boot - How to log all requests and responses with exceptions in single place?

In order to log all the requests with input parameters and body, we can use filters and interceptors. But while using a filter or interceptor, we cannot print the request body multiple times. The better way is we can use spring-AOP. By using this we can decouple the logging mechanism from the application. AOP can be used for logging Input and output of each method in the application.

My solution is:

 import org.aspectj.lang.ProceedingJoinPoint;
 import org.aspectj.lang.annotation.Around;
 import org.aspectj.lang.annotation.Aspect;
 import org.aspectj.lang.annotation.Pointcut;
 import org.aspectj.lang.reflect.CodeSignature;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Component;
 import com.fasterxml.jackson.databind.ObjectMapper;
public class LoggingAdvice {
private static final Logger logger = 

//here we can provide any methodName, packageName, className 
@Pointcut(value = "execution(**.*.*(..) )")
public void myPointcut() {


public Object applicationLogger(ProceedingJoinPoint pjt) throws Throwable {
    ObjectMapper mapper = new ObjectMapper();
    String methodName = pjt.getSignature().getName();
    String className = pjt.getTarget().getClass().toString();
    String inputParams = this.getInputArgs(pjt ,mapper);"method invoked from " + className + " : " + methodName + "--Request Payload::::"+inputParams);
    Object object = pjt.proceed();
    try {"Response Object---" + mapper.writeValueAsString(object));
    } catch (Exception e) {
    return object;

private String getInputArgs(ProceedingJoinPoint pjt,ObjectMapper mapper) {
    Object[] array = pjt.getArgs();
    CodeSignature signature = (CodeSignature) pjt.getSignature();

    StringBuilder sb = new StringBuilder();
    int i = 0;
    String[] parameterNames = signature.getParameterNames();
    int maxArgs = parameterNames.length;
    for (String name : signature.getParameterNames()) {
        try {
            if(i != maxArgs -1 ) {
        } catch (Exception e) {
    return sb.append("}").toString();


How can I inspect element in an Android browser?

If you want to inspect html, css or maybe you need js console in your mobile browser . You can use excelent tool eruda Using it you have the same Developer Tools on your mobile browser like in your desctop device. Dont forget to upvote :) Here is a link

Looping from 1 to infinity in Python

If you're doing that in C, then your judgement there is as cloudy as it would be in Python :-)

For a loop that exits on a simple condition check at the start of each iteration, it's more usual (and clearer, in my opinion) to just do that in the looping construct itself. In other words, something like (if you need i after loop end):

int i = 0;
while (! thereIsAReasonToBreak(i)) {
    // do something

or (if i can be scoped to just the loop):

for (int i = 0; ! thereIsAReasonToBreak(i); ++i) {
    // do something

That would translate to the Python equivalent:

i = 0
while not there_is_a_reason_to_break(i):
    # do something
    i += 1

Only if you need to exit in the middle of the loop somewhere (or if your condition is complex enough that it would render your looping statement far less readable) would you need to worry about breaking.

When your potential exit is a simple one at the start of the loop (as it appears to be here), it's usually better to encode the exit into the loop itself.

Git ignore file for Xcode projects

Heres a script I made to auto create your .gitignore and .gitattributes files using Xcode... I hacked it together with a few other people's stuff. Have fun!


No warranties... I suck at most of this - so use at your own peril

How can I define fieldset border color?

If you don't want 3D border use:

border:#f00 1px solid;

Creating a div element in jQuery

You can create separate tags using the .jquery() method. And create child tags by using the .append() method. As jQuery supports chaining, you can also apply CSS in two ways. Either specify it in the class or just call .attr():

var lTag = jQuery("<li/>")

var aHref = jQuery('<a/>',{         
}).appendTo(lTag).attr("href", data.mediumImageURL);

}).appendTo(aHref).attr("src", data.mediumImageURL).attr("alt", data.altText);

Firstly I am appending a list tag to my div tag and inserting JSON data into it. Next, I am creating a child tag of list, provided some attribute. I have assigned the value to a variable, so that it would be easy for me to append it.

Column/Vertical selection with Keyboard in SublimeText 3

This should do it:

  1. Ctrl+A - select all.
  2. Ctrl+Shift+L - split selection into lines.
  3. Then move all cursors with left/right, select with Shift+left/right. Move all cursors to start of line with Home.

Merge development branch with master

I generally like to merge master into the development first so that if there are any conflicts, I can resolve in the development branch itself and my master remains clean.

(on branch development)$ git merge master
(resolve any merge conflicts if there are any)
git checkout master
git merge development (there won't be any conflicts now)

There isn't much of a difference in the two approaches, but I have noticed sometimes that I don't want to merge the branch into master yet, after merging them, or that there is still more work to be done before these can be merged, so I tend to leave master untouched until final stuff.

EDIT: From comments

If you want to keep track of who did the merge and when, you can use --no-ff flag while merging to do so. This is generally useful only when merging development into the master (last step), because you might need to merge master into development (first step) multiple times in your workflow, and creating a commit node for these might not be very useful.

git merge --no-ff development

What is a typedef enum in Objective-C?

Three things are being declared here: an anonymous enumerated type is declared, ShapeType is being declared a typedef for that anonymous enumeration, and the three names kCircle, kRectangle, and kOblateSpheroid are being declared as integral constants.

Let's break that down. In the simplest case, an enumeration can be declared as

enum tagname { ... };

This declares an enumeration with the tag tagname. In C and Objective-C (but not C++), any references to this must be preceded with the enum keyword. For example:

enum tagname x;  // declare x of type 'enum tagname'
tagname x;  // ERROR in C/Objective-C, OK in C++

In order to avoid having to use the enum keyword everywhere, a typedef can be created:

enum tagname { ... };
typedef enum tagname tagname;  // declare 'tagname' as a typedef for 'enum tagname'

This can be simplified into one line:

typedef enum tagname { ... } tagname;  // declare both 'enum tagname' and 'tagname'

And finally, if we don't need to be able to use enum tagname with the enum keyword, we can make the enum anonymous and only declare it with the typedef name:

typedef enum { ... } tagname;

Now, in this case, we're declaring ShapeType to be a typedef'ed name of an anonymous enumeration. ShapeType is really just an integral type, and should only be used to declare variables which hold one of the values listed in the declaration (that is, one of kCircle, kRectangle, and kOblateSpheroid). You can assign a ShapeType variable another value by casting, though, so you have to be careful when reading enum values.

Finally, kCircle, kRectangle, and kOblateSpheroid are declared as integral constants in the global namespace. Since no specific values were specified, they get assigned to consecutive integers starting with 0, so kCircle is 0, kRectangle is 1, and kOblateSpheroid is 2.

php artisan migrate throwing [PDO Exception] Could not find driver - Using Laravel

I was also getting the same error --> "[PDOException]
could not find driver "

After that I used many commands but not didn't get any help

Finally I used the following command, which solved my problem.

sudo apt-get install php5-sqlite

ASP.NET MVC3 - textarea with @Html.EditorFor

Someone asked about adding attributes (specifically, 'rows' and 'cols'). If you're using Razor, you could just do this:

@Html.TextAreaFor(model => model.Text, new { cols = 35, @rows = 3 })

That works for me. The '@' is used to escape keywords so they are treated as variables/properties.

correct way to use super (argument passing)

As explained in Python's super() considered super, one way is to have class eat the arguments it requires, and pass the rest on. Thus, when the call-chain reaches object, all arguments have been eaten, and object.__init__ will be called without arguments (as it expects). So your code should look like this:

class A(object):
    def __init__(self, *args, **kwargs):
        print "A"
        super(A, self).__init__(*args, **kwargs)

class B(object):
    def __init__(self, *args, **kwargs):
        print "B"
        super(B, self).__init__(*args, **kwargs)

class C(A):
    def __init__(self, arg, *args, **kwargs):
        print "C","arg=",arg
        super(C, self).__init__(*args, **kwargs)

class D(B):
    def __init__(self, arg, *args, **kwargs):
        print "D", "arg=",arg
        super(D, self).__init__(*args, **kwargs)

class E(C,D):
    def __init__(self, arg, *args, **kwargs):
        print "E", "arg=",arg
        super(E, self).__init__(*args, **kwargs)

print "MRO:", [x.__name__ for x in E.__mro__]
E(10, 20, 30)

How to bind inverse boolean properties in WPF?

Add one more property in your view model, which will return reverse value. And bind that to button. Like;

in view model:

public bool IsNotReadOnly{get{return !IsReadOnly;}}

in xaml:

IsEnabled="{Binding IsNotReadOnly"}

How can I plot data with confidence intervals?

Here is a solution using functions plot(), polygon() and lines().

 df <- data.frame(x =1:10,
                 F =runif(10,1,2),
                 L =runif(10,0,1),
                 U =runif(10,2,3))

 plot(df$x, df$F, ylim = c(0,4), type = "l")
 #make polygon where coordinates start with lower limit and 
 # then upper limit in reverse order
 polygon(c(df$x,rev(df$x)),c(df$L,rev(df$U)),col = "grey75", border = FALSE)
 lines(df$x, df$F, lwd = 2)
 #add red lines on borders of polygon
 lines(df$x, df$U, col="red",lty=2)
 lines(df$x, df$L, col="red",lty=2)

enter image description here

Now use example data provided by OP in another question:

   Lower <- c(0.418116841, 0.391011834, 0.393297710,
        0.531378573, 0.311448219, 0.392045751,0.153614913, 0.366684097,
        0.161100849,0.700274810,0.629714150, 0.661641288, 0.533404093,
        0.412427559, 0.432905333, 0.525306427,0.224292061,
        0.28893064,0.099543648, 0.342995605,0.086973739,0.289030388,
        0.081230826,0.164505624, -0.031290586,0.148383474,0.070517523,0.009686605,
        -0.052703529,0.475924192,0.253382210, 0.354011010,0.130295355,0.102253218,
        0.335833224,0.037258467, 0.141312363,0.361392799,0.129791998,

 Upper.limit <- c(0.6446223,0.6177311, 0.6034427, 0.5726503,
      0.7644718, 0.4585430, 0.8205418, 0.7154043,0.7370033,
      0.5285199, 0.5973728, 0.3764209, 0.5818298,
      0.3960867,0.8972357, 0.8370151, 0.8359921, 0.7449118,
      0.6152879, 0.6200704, 0.7041068, 0.4541011, 0.5222653,
      0.3472364, 0.5956551, 0.3068065, 0.5112895, 0.3081448,
      0.3745473, 0.1931089, 0.3890704, 0.3031025, 0.2472591,
      0.1976092, 0.6906118, 0.4736644, 0.5770463, 0.3528607,
      0.3307651, 0.6681629, 0.7476231, 0.5959025, 0.7128883,
      0.3451623, 0.5609742, 0.4739216, 0.3694883, 0.5609220,
      0.6343219, 0.3647751, 0.4247147, 0.6996334, 0.5562876,
      0.2586490, 0.3750040, 0.5922248, 0.3626322, 0.5243285,
      0.5548211, 0.7409648, 0.5820070, 0.5530232, 0.6863703,
      0.7206998, 0.4952387, 0.4993264, 0.3527727, 0.2203694,
      0.2583149, 0.3035342, 0.3462009, 0.3003602, 0.4506054,
      0.3359478, 0.4834151, 0.4391330, 0.5273411, 0.3947622,
      0.4133769, 0.5288060, 0.7492071, 0.5381701, 0.4825456,
      0.6121942, 0.6192227, 0.3784870, 0.2574025, 0.3704140,
      0.2945623, 0.6532694, 0.2697202, 0.3652230, 0.3696383,
      0.5268808, 0.1545602, 0.2221450, 0.3553377, 0.5204076,

  Fitted.values<- c(0.53136955, 0.50437146, 0.49837019,
  0.46939721, 0.66721423, 0.34165926, 0.70985388, 0.61383696,
  0.63419092, 0.41998407, 0.49470927, 0.26501789, 0.47425695,
  0.27859380, 0.79875525, 0.73336461, 0.74881668, 0.63915795,
  0.51385774, 0.52648789, 0.61470661, 0.33919656, 0.40559797,
  0.22339000, 0.46932536, 0.19689011, 0.40015996, 0.19468781,
  0.26952645, 0.08090917, 0.26872696, 0.18680999, 0.12847285,
  0.07245286, 0.58326799, 0.36352329, 0.46552867, 0.24157804,
  0.21650915, 0.55738088, 0.64797691, 0.49494416, 0.59728999,
  0.22848680, 0.45030036, 0.37087676, 0.25147426, 0.45445930,
  0.52339711, 0.24922310, 0.30184215, 0.59185198, 0.44606040,
  0.14795374, 0.25815819, 0.47680880, 0.24621212, 0.40404398,
  0.44435727, 0.65524894, 0.48363255, 0.45461258, 0.58409323,
  0.62599114, 0.38418264, 0.38357103, 0.24545011, 0.11461756,
  0.13821664, 0.19183886, 0.23203127, 0.18702881, 0.34030391,
  0.22090140, 0.37289121, 0.32846615, 0.40822456, 0.27801706,
  0.31652008, 0.41746184, 0.64364785, 0.42944100, 0.37347037,
  0.50412786, 0.50828681, 0.26510696, 0.15302635, 0.25116438,
  0.18559609, 0.53955941, 0.16920626, 0.26018389, 0.25378867,
  0.41439675, 0.04157232, 0.09600163, 0.23739430, 0.41666762,

Assemble into a data frame (no x provided, so using indices)

 df2 <- data.frame(x=seq(length(Fitted.values)),
 #make polygon where coordinates start with lower limit and then upper limit in reverse order
 with(df2,polygon(c(x,rev(x)),c(lwr,rev(upr)),col = "grey75", border = FALSE))

enter image description here

How to concatenate properties from multiple JavaScript objects

ECMAScript 6 has spread syntax. And now you can do this:

const obj1 = { 1: 11, 2: 22 };_x000D_
const obj2 = { 3: 33, 4: 44 };_x000D_
const obj3 = { ...obj1, ...obj2 };_x000D_
console.log(obj3); // {1: 11, 2: 22, 3: 33, 4: 44}

How to remove numbers from string using Regex.Replace?

As a string extension:

    public static string RemoveIntegers(this string input)
        return Regex.Replace(input, @"[\d-]", string.Empty);


"My text 1232".RemoveIntegers(); // RETURNS "My text "

How to mock a final class with mockito

Add these dependencies for run mockito successfully :

testImplementation 'org.mockito:mockito-core:2.24.5'
testImplementation "org.mockito:mockito-inline:2.24.5"

Change header background color of modal of twitter bootstrap

You can use the css below, put this in your custom css to override the bootstrap css.

.modal-header {
    padding:9px 15px;
    border-bottom:1px solid #eee;
    background-color: #0480be;
    -webkit-border-top-left-radius: 5px;
    -webkit-border-top-right-radius: 5px;
    -moz-border-radius-topleft: 5px;
    -moz-border-radius-topright: 5px;
     border-top-left-radius: 5px;
     border-top-right-radius: 5px;

powerpoint loop a series of animation

Unfortunately you're probably done with the animation and presentation already. In the hopes this answer can help future questioners, however, this blog post has a walkthrough of steps that can loop a single slide as a sort of sub-presentation.

First, click Slide Show > Set Up Show.

Put a checkmark to Loop continuously until 'Esc'.

Click Ok. Now, Click Slide Show > Custom Shows. Click New.

Select the slide you are looping, click Add. Click Ok and Close.

Click on the slide you are looping. Click Slide Show > Slide Transition. Under Advance slide, put a checkmark to Automatically After. This will allow the slide to loop automatically. Do NOT Apply to all slides.

Right click on the thumbnail of the current slide, select Hide Slide.

Now, you will need to insert a new slide just before the slide you are looping. On the new slide, insert an action button. Set the hyperlink to the custom show you have created. Put a checkmark on "Show and Return"

This has worked for me.

Java 'file.delete()' Is not Deleting Specified File

If you want to delete file first close all the connections and streams. after that delete the file.

How do I simulate placeholder functionality on input date field?

You can do something like this:

<input onfocus="(this.type='date')" class="js-form-control" placeholder="Enter Date">

git with development, staging and production branches

Actually what made this so confusing is that the Beanstalk people stand behind their very non-standard use of Staging (it comes before development in their diagram, and it's not a mistake!

Free XML Formatting tool

If you are a programmer, many XML parsing programming libraries will let you parse XML, then output it - and generating pretty printed, indented output is an output option.

Visual Studio move project to a different folder

  1. Close your solution in VS2012
  2. Move your project to the new location
  3. Open your solution
  4. Select the project that failed to load
  5. In the Properties tool window, there an editable “File path” entry that allows you to select the new project location
  6. Set the new path
  7. Right click on the project and click reload

ORA-12514 TNS:listener does not currently know of service requested in connect descriptor

This really should be a comment to Brad Rippe's answer, but alas, not enough rep. That answer got me 90% of the way there. In my case, the installation and configuration of the databases put entries in the tnsnames.ora file for the databases I was running. First, I was able to connect to the database by setting the environment variables (Windows):

set ORACLE_SID=mydatabase
set ORACLE_HOME=C:\Oracle\product\11.2.0\dbhome_1

and then connecting using

sqlplus / as sysdba

Next, running the command from Brad Rippe's answer:

select value from v$parameter where name='service_names';

showed that the names didn't match exactly. The entries as created using Oracle's Database Configuration Assistant where originally:

    (ADDRESS = (PROTOCOL = TCP)(HOST = = 1521))

The service name from the query was just mydatabase rather than I edited the tnsnames.ora file to just the base name without the domain portion so they looked like this:

    (ADDRESS = (PROTOCOL = TCP)(HOST = = 1521))
      (SERVICE_NAME = mydatabase)

I restarted the TNS Listener service (I often use lsnrctl stop and lsnrctl start from an administrator command window [or Windows Powershell] instead of the Services control panel, but both work.) After that, I was able to connect.

C++ catching all exceptions

A generic exception catching mechanism would prove extremely useful.

Doubtful. You already know your code is broken, because it's crashing. Eating exceptions may mask this, but that'll probably just result in even nastier, more subtle bugs.

What you really want is a debugger...

using jquery $.ajax to call a PHP function

You may use my library that does that automatically, I've been improving it for the past 2 years

   'phpfunction' => function($data){
      /* Do your thing */
      return PheryResponse::factory(); // do your dom manipulation, return JSON, etc

The javascript would be simple as


You can pass all the dynamic javascript part to the server, with a query builder like chainable interface, and you may pass any type of data back to the PHP. For example, some functions that would take too much space in the javascript side, could be called in the server using this (in this example, mcrypt, that in javascript would be almost impossible to accomplish):

function mcrypt(variable, content, key){
  phery.remote('mcrypt_encrypt', {'var': variable, 'content': content, 'key':key || false});

//would use it like (you may keep the key on the server, safer, unless it's encrypted for the user)
window.variable = '';
mcrypt('variable', 'This must be encoded and put inside variable', 'my key');

and in the server

  'mcrypt_encrypt' => function($data){
     $r = new PheryResponse;

     $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
     $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
     $encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $data['key'] ? : 'my key', $data['content'], MCRYPT_MODE_ECB, $iv);
     return $r->set_var($data['variable'], $encrypted);
     // or call a callback with the data, $r->call($data['callback'], $encrypted);

Now the variable will have the encrypted data.

Gson - convert from Json to a typed ArrayList<T>

You may use TypeToken to load the json string into a custom object.

logs = gson.fromJson(br, new TypeToken<List<JsonLog>>(){}.getType());


Represents a generic type T.

Java doesn't yet provide a way to represent generic types, so this class does. Forces clients to create a subclass of this class which enables retrieval the type information even at runtime.

For example, to create a type literal for List<String>, you can create an empty anonymous inner class:

TypeToken<List<String>> list = new TypeToken<List<String>>() {};

This syntax cannot be used to create type literals that have wildcard parameters, such as Class<?> or List<? extends CharSequence>.


If you need to do it in Kotlin you can do it like this:

val myType = object : TypeToken<List<JsonLong>>() {}.type
val logs = gson.fromJson<List<JsonLong>>(br, myType)

Or you can see this answer for various alternatives.

Can I add and remove elements of enumeration at runtime in Java

You can load a Java class from source at runtime. (Using JCI, BeanShell or JavaCompiler)

This would allow you to change the Enum values as you wish.

Note: this wouldn't change any classes which referred to these enums so this might not be very useful in reality.

How can I run PowerShell with the .NET 4 runtime?

Actually, you can get PowerShell to run using .NET 4 without affecting other .NET applications. I needed to do so to use the new HttpWebRequest "Host" property, however changing the "OnlyUseLatestCLR" broke Fiddler as that could not be used under .NET 4.

The developers of PowerShell obviously foresaw this happening, and they added a registry key to specify what version of the Framework it should use. One slight issue is that you need to take ownership of the registry key before changing it, as even administrators do not have access.

  • HKLM:\Software\Microsoft\Powershell\1\PowerShellEngine\RuntimeVersion (64 bit and 32 bit)
  • HKLM:\Software\Wow6432Node\Microsoft\Powershell\1\PowerShellEngine\RuntimeVersion (32 bit on 64 bit machine)

Change the value of that key to the required version. Keep in mind though that some snapins may no longer load unless they are .NET 4 compatible (WASP is the only one I have had trouble with, but I don't really use it anyway). VMWare, SQL Server 2008, PSCX, Active Directory (Microsoft and Quest Software) and SCOM all work fine.

Is it possible to forward-declare a function in Python?

TL;DR: Python does not need forward declarations. Simply put your function calls inside function def definitions, and you'll be fine.

def foo(count):
    print("foo "+str(count))

def bar(count):
    print("bar "+str(count))


recursive function definitions, perfectly successfully gives:

foo 3
bar 2
foo 1
bar 0



def bug(count):
    print("bug never runs "+str(count))

print("Does not print this.")

breaks at the top-level invocation of a function that hasn't been defined yet, and gives:

Traceback (most recent call last):
  File "./", line 1, in <module>
NameError: name 'bug' is not defined

Python is an interpreted language, like Lisp. It has no type checking, only run-time function invocations, which succeed if the function name has been bound and fail if it's unbound.

Critically, a function def definition does not execute any of the funcalls inside its lines, it simply declares what the function body is going to consist of. Again, it doesn't even do type checking. So we can do this:

def uncalled():
    print("I'm not invoked!")

print("Only run this one line.")

and it runs perfectly fine (!), with output

Only run this one line.

The key is the difference between definitions and invocations.

The interpreter executes everything that comes in at the top level, which means it tries to invoke it. If it's not inside a definition.
Your code is running into trouble because you attempted to invoke a function, at the top level in this case, before it was bound.

The solution is to put your non-top-level function invocations inside a function definition, then call that function sometime much later.

The business about "if __ main __" is an idiom based on this principle, but you have to understand why, instead of simply blindly following it.

There are certainly much more advanced topics concerning lambda functions and rebinding function names dynamically, but these are not what the OP was asking for. In addition, they can be solved using these same principles: (1) defs define a function, they do not invoke their lines; (2) you get in trouble when you invoke a function symbol that's unbound.

How do I mock a service that returns promise in AngularJS Jasmine unit test?

Honestly.. you are going about this the wrong way by relying on inject to mock a service instead of module. Also, calling inject in a beforeEach is an anti-pattern as it makes mocking difficult on a per test basis.

Here is how I would do this...

module(function ($provide) {
  // By using a decorator we can access $q and stub our method with a promise.
  $provide.decorator('myOtherService', function ($delegate, $q) {

    $delegate.makeRemoteCallReturningPromise = function () {
      var dfd = $q.defer();
      dfd.resolve('some value');
      return dfd.promise;

Now when you inject your service it will have a properly mocked method for usage.

C# - How to get Program Files (x86) on Windows 64 bit

Note, however, that the ProgramFiles(x86) environment variable is only available if your application is running 64-bit.

If your application is running 32-bit, you can just use the ProgramFiles environment variable whose value will actually be "Program Files (x86)".

How to use custom packages

For a project hosted on GitHub, here's what people usually do:


package mylib



import ""


Change font size of UISegmentedControl

Another option is to apply a transform to the control. However, it will scale down everything including the control borders.

segmentedControl.transform = CGAffineTransformMakeScale(.6f, .6f);

"Content is not allowed in prolog" when parsing perfectly valid XML on GAE

In my instance of the problem, the solution was to replace german umlauts (äöü) with their HTML-equivalents...

How to submit form on change of dropdown list?

other than using this.form.submit() you also submiting by id or name. example i have form like this : <form action="" name="PostName" id="IdName">

  1. By Name : <select onchange="PostName.submit()">

  2. By Id : <select onchange="IdName.submit()">

Setting the default page for ASP.NET (Visual Studio) server configuration

This One Method For Published Solution To Show SpeciFic Page on startup.

Here Is the Route Example to Redirect to Specific Page...

public class RouteConfig
    public static void RegisterRoutes(RouteCollection routes)

            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            namespaces: new[] { "YourSolutionName.Controllers" }

By Default Home Controllers Index method is executed when application is started, Here You Can Define yours.

Note : I am Using Visual Studio 2013 and "YourSolutionName" is to changed to your project Name..

Class type check in TypeScript

4.19.4 The instanceof operator

The instanceof operator requires the left operand to be of type Any, an object type, or a type parameter type, and the right operand to be of type Any or a subtype of the 'Function' interface type. The result is always of the Boolean primitive type.

So you could use

mySprite instanceof Sprite;

Note that this operator is also in ActionScript but it shouldn't be used there anymore:

The is operator, which is new for ActionScript 3.0, allows you to test whether a variable or expression is a member of a given data type. In previous versions of ActionScript, the instanceof operator provided this functionality, but in ActionScript 3.0 the instanceof operator should not be used to test for data type membership. The is operator should be used instead of the instanceof operator for manual type checking, because the expression x instanceof y merely checks the prototype chain of x for the existence of y (and in ActionScript 3.0, the prototype chain does not provide a complete picture of the inheritance hierarchy).

TypeScript's instanceof shares the same problems. As it is a language which is still in its development I recommend you to state a proposal of such facility.

See also:

How can I use onItemSelected in Android?

Another thing: When you have more than one spinner in your layout, you have to implement a switch selection in the onItemSlected() method to know which widget was clicked. Something like this:

public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    switch (parent.getId()){
            //Do something
            Toast.makeText(this, "Alarm Selected: " + parent.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();
            //Do another thing 
            Toast.makeText(this, "Option Selected: " + parent.getSelectedItem().toString(), Toast.LENGTH_SHORT).show();

Stop an input field in a form from being submitted

You could insert input fields without "name" attribute:

<input type="text" id="in-between" />

Or you could simply remove them once the form is submitted (in jQuery):

$("form").submit(function() {

Postgres: How to convert a json string to text?

There is no way in PostgreSQL to deconstruct a scalar JSON object. Thus, as you point out,

select  length(to_json('Some "text"'::TEXT) ::TEXT);

is 15,

The trick is to convert the JSON into an array of one JSON element, then extract that element using ->>.

select length( array_to_json(array[to_json('Some "text"'::TEXT)])->>0 );

will return 11.

Creating a dictionary from a CSV file

import csv
reader = csv.reader(open('filename.csv', 'r'))
d = {}
for row in reader:
   k, v = row
   d[k] = v

In CSS Flexbox, why are there no "justify-items" and "justify-self" properties?

I know this doesn't use flexbox, but for the simple use-case of three items (one at left, one at center, one at right), this can be accomplished easily using display: grid on the parent, grid-area: 1/1/1/1; on the children, and justify-self for positioning of those children.

<div style="border: 1px solid red; display: grid; width: 100px; height: 25px;">_x000D_
  <div style="border: 1px solid blue; width: 25px; grid-area: 1/1/1/1; justify-self: left;"></div>_x000D_
  <div style="border: 1px solid blue; width: 25px; grid-area: 1/1/1/1; justify-self: center;"></div>_x000D_
  <div style="border: 1px solid blue; width: 25px; grid-area: 1/1/1/1; justify-self: right;"></div>_x000D_

Passing parameters to a JDBC PreparedStatement

If you are using prepared statement, you should use it like this:

"SELECT * from employee WHERE userID = ?"

Then use:

statement.setString(1, userID);

? will be replaced in your query with the user ID passed into setString method.

Take a look here how to use PreparedStatement.

How to refer to Excel objects in Access VBA?

I dissent from both the answers. Don't create a reference at all, but use late binding:

  Dim objExcelApp As Object
  Dim wb As Object

  Sub Initialize()
    Set objExcelApp = CreateObject("Excel.Application")
  End Sub

  Sub ProcessDataWorkbook()
     Set wb = objExcelApp.Workbooks.Open("path to my workbook")
     Dim ws As Object
     Set ws = wb.Sheets(1)

     ws.Cells(1, 1).Value = "Hello"
     ws.Cells(1, 2).Value = "World"

     'Close the workbook
     Set wb = Nothing
  End Sub

You will note that the only difference in the code above is that the variables are all declared as objects and you instantiate the Excel instance with CreateObject().

This code will run no matter what version of Excel is installed, while using a reference can easily cause your code to break if there's a different version of Excel installed, or if it's installed in a different location.

Also, the error handling could be added to the code above so that if the initial instantiation of the Excel instance fails (say, because Excel is not installed or not properly registered), your code can continue. With a reference set, your whole Access application will fail if Excel is not installed.

Can VS Code run on Android?

The accepted answer is correct as asked, below answers the opposite question of developing Android on VS Code.


Ultimately you can automate building and running your app on a device emulator by adding the function below to your $PATH and running runDebugApp <module> <start activity> from the integrated terminal:

# run android app
# usage runDebugApp [module] [fully qualified start activity com.package/com.package.MainActivity]
function runDebugApp(){
  ./gradlew -offline :"$1":installDebug && adb shell am start "$2" && adb logcat -d > logcat.log

Jackson JSON: get node name from json-tree

For Jackson 2+ (com.fasterxml.jackson), the methods are little bit different:

Iterator<Entry<String, JsonNode>> nodes = rootNode.get("foo").fields();

while (nodes.hasNext()) {
  Map.Entry<String, JsonNode> entry = (Map.Entry<String, JsonNode>);"key --> " + entry.getKey() + " value-->" + entry.getValue());

Delete dynamically-generated table row using jQuery

A simple solution is encapsulate code of button event in a function, and call it when you add TRs too:

 var i = 1;
$("#addbutton").click(function() {
  $("table tr:first").clone().find("input").each(function() {
      'id': function(_, id) {return id + i },
      'name': function(_, name) { return name + i },
      'value': ''               


function applyRemoveEvent(){
    $('button.removebutton').on('click',function() {
      $(this).closest( 'tr').remove();
      return false;


php - How do I fix this illegal offset type error

Use trim($source) before $s[$source].

Simulating group_concat MySQL function in Microsoft SQL Server 2005?

I may be a bit late to the party but this method works for me and is easier than the COALESCE method.

             (SELECT ',' + Column_Name 
              FROM Table_Name
              FOR XML PATH (''))
             , 1, 1, '')

2D character array initialization in C

C strings are enclosed in double quotes:

const char *options[2][100];

options[0][0] = "test1";
options[1][0] = "test2";

Re-reading your question and comments though I'm guessing that what you really want to do is this:

const char *options[2] = { "test1", "test2" };

printing out a 2-D array in Matrix format

int[][] matrix = {


public void printMatrix(int[][] m){
        int rows = m.length;
        int columns = m[0].length;
        String str = "|\t";

        for(int i=0;i<rows;i++){
            for(int j=0;j<columns;j++){
                str += m[i][j] + "\t";

            System.out.println(str + "|");
            str = "|\t";

    }catch(Exception e){System.out.println("Matrix is empty!!");}


|   1   2   3   |
|   4   5   6   |
|   7   8   9   |
|   10  11  12  |

How to substitute shell variables in complex text files

Actually you need to change your read to read -r which will make it ignore backslashes.

Also, you should escape quotes and backslashes. So

while read -r line; do
  eval echo "\"$line\""
done > destination.txt < source.txt

Still a terrible way to do expansion though.

PHP parse/syntax errors; and how to solve them

I think this topic is totally overdiscussed/overcomplicated. Using an IDE is THE way to go to completely avoid any syntax errors. I would even say that working without an IDE is kind of unprofessional. Why? Because modern IDEs check your syntax after every character you type. When you code and your entire line turns red, and a big warning notice shows you the exact type and the exact position of the syntax error, then there's absolutely no need to search for another solution.

Using a syntax-checking IDE means:

You'll (effectively) never run into syntax errors again, simply because you see them right as you type. Seriously.

Excellent IDEs with syntax check (all of them are available for Linux, Windows and Mac):

  1. NetBeans [free]
  2. PHPStorm [$199 USD]
  3. Eclipse with PHP Plugin [free]
  4. Sublime [$80 USD] (mainly a text editor, but expandable with plugins, like PHP Syntax Parser)

Subscript out of range error in this Excel VBA script

Set sh1 = Worksheets(filenum(lngPosition)).Activate

You are getting Subscript out of range error error becuase it cannot find that Worksheet.

Also please... please... please do not use .Select/.Activate/Selection/ActiveCell You might want to see How to Avoid using Select in Excel VBA Macros.

How to download Visual Studio 2017 Community Edition for offline installation?

Here you can download visual studio 2017 initial installer:

Run it and after few minutes it will ask what components do you want to install and in the right bottom there will be two option
"Install while downloading"
"Download all, then install"

Select any option and click install.

Save base64 string as PDF at client side with JavaScript

I know this question is old, but also wanted to accomplish this and came across it while looking. For internet explorer I used code from here to save a Blob. To create a blob from the base64 string there were many results on this site, so its not my code I just can't remember the specific source:

function b64toBlob(b64Data, contentType) {
    contentType = contentType || '';
    var sliceSize = 512;
    b64Data = b64Data.replace(/^[^,]+,/, '');
    b64Data = b64Data.replace(/\s/g, '');
    var byteCharacters = window.atob(b64Data);
    var byteArrays = [];

    for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
        var slice = byteCharacters.slice(offset, offset + sliceSize);

        var byteNumbers = new Array(slice.length);
        for (var i = 0; i < slice.length; i++) {
            byteNumbers[i] = slice.charCodeAt(i);

        var byteArray = new Uint8Array(byteNumbers);


    var blob = new Blob(byteArrays, {type: contentType});
    return blob;

Using the linked filesaver:

if (window.saveAs) { window.saveAs(blob, name); }
    else { navigator.saveBlob(blob, name); }

How to work with complex numbers in C?

Complex types are in the C language since C99 standard (-std=c99 option of GCC). Some compilers may implement complex types even in more earlier modes, but this is non-standard and non-portable extension (e.g. IBM XL, GCC, may be intel,... ).

You can start from - it gives a description of functions from complex.h

This manual also gives some info about macros.

To declare a complex variable, use

  double _Complex  a;        // use c* functions without suffix


  float _Complex   b;        // use c*f functions - with f suffix
  long double _Complex c;    // use c*l functions - with l suffix

To give a value into complex, use _Complex_I macro from complex.h:

  float _Complex d = 2.0f + 2.0f*_Complex_I;

(actually there can be some problems here with (0,-0i) numbers and NaNs in single half of complex)

Module is cabs(a)/cabsl(c)/cabsf(b); Real part is creal(a), Imaginary is cimag(a). carg(a) is for complex argument.

To directly access (read/write) real an imag part you may use this unportable GCC-extension:

 __real__ a = 1.4;
 __imag__ a = 2.0;
 float b = __real__ a;

How to update an object in a List<> in C#

var itemIndex = listObject.FindIndex(x => x == SomeSpecialCondition());
var item = listObject.ElementAt(itemIndex);
item.SomePropYouWantToChange = "yourNewValue";

Get date from input form within PHP

Validate the INPUT.

$time = strtotime($_POST['dateFrom']);
if ($time) {
  $new_date = date('Y-m-d', $time);
  echo $new_date;
} else {
   echo 'Invalid Date: ' . $_POST['dateFrom'];
  // fix it.

Why does Eclipse Java Package Explorer show question mark on some classes?

In a enabled project the small question mark (?) indicates that your file is not yet added to the SVN repository.

The small orange rectangle is an indication that your file is committed in the repository.

An asterisk (*) indicates a local change.

SQL recursive query on self referencing table (Oracle)

It's a little on the cumbersome side, but I believe this should work (without the extra join). This assumes that you can choose a character that will never appear in the field in question, to act as a separator.

You can do it without nesting the select, but I find this a little cleaner that having four references to SYS_CONNECT_BY_PATH.

select id, 
         when lvl <> 1 
         then substr(name_path,
         end as name 
from (
  SELECT id, parent_id, sys_connect_by_path(name,'|') as name_path, level as lvl
  FROM tbl 
  START WITH id = 1 
  CONNECT BY PRIOR id = parent_id)

What does string::npos mean in this code?

npos is just a token value that tells you that find() did not find anything (probably -1 or something like that). find() checks for the first occurence of the parameter, and returns the index at which the parameter begins. For Example,

  string name = "asad.txt";
  int i = name.find(".txt");
  //i holds the value 4 now, that's the index at which ".txt" starts
  if (i==string::npos) //if ".txt" was NOT found - in this case it was, so  this condition is false

How to replace multiple patterns at once with sed?

This might work for you (GNU sed):

sed -r '1{x;s/^/:abbc:bcab/;x};G;s/^/\n/;:a;/\n\n/{P;d};s/\n(ab|bc)(.*\n.*:(\1)([^:]*))/\4\n\2/;ta;s/\n(.)/\1\n/;ta' file

This uses a lookup table which is prepared and held in the hold space (HS) and then appended to each line. An unique marker (in this case \n) is prepended to the start of the line and used as a method to bump-along the search throughout the length of the line. Once the marker reaches the end of the line the process is finished and is printed out the lookup table and markers being discarded.

N.B. The lookup table is prepped at the very start and a second unique marker (in this case :) chosen so as not to clash with the substitution strings.

With some comments:

sed -r '
  # initialize hold with :abbc:bcab
  1 {

  G        # append hold to patt (after a \n)

  s/^/\n/  # prepend a \n


  /\n\n/ {
    P      # print patt up to first \n
    d      # delete patt & start next cycle

  ta       # goto a if sub occurred

  s/\n(.)/\1\n/  # move one char past the first \n
  ta       # goto a if sub occurred

The table works like this:

   **   **   replacement
 **   **     pattern

How to display the first few characters of a string in Python?

You can 'slice' a string very easily, just like you'd pull items from a list:

a_string = 'This is a string'

To get the first 4 letters:

first_four_letters = a_string[:4]
>>> 'This'

Or the last 5:

last_five_letters = a_string[-5:]
>>> 'string'

So applying that logic to your problem:

the_string = '416d76b8811b0ddae2fdad8f4721ddbe|d4f656ee006e248f2f3a8a93a8aec5868788b927|12a5f648928f8e0b5376d2cc07de8e4cbf9f7ccbadb97d898373f85f0a75c47f '
first_32_chars = the_string[:32]
>>> 416d76b8811b0ddae2fdad8f4721ddbe

Using gdb to single-step assembly code outside specified executable causes error "cannot find bounds of current function"

You can use stepi or nexti (which can be abbreviated to si or ni) to step through your machine code.

How do I get ruby to print a full backtrace instead of a truncated one?

[examine all threads backtraces to find the culprit]
Even fully expanded call stack can still hide the actual offending line of code from you when you use more than one thread!

Example: One thread is iterating ruby Hash, other thread is trying to modify it. BOOM! Exception! And the problem with the stack trace you get while trying to modify 'busy' hash is that it shows you chain of functions down to the place where you're trying to modify hash, but it does NOT show who's currently iterating it in parallel (who owns it)! Here's the way to figure that out by printing stack trace for ALL currently running threads. Here's how you do this:

# This solution was found in comment by @thedarkone on
rescue Object => boom

    thread_count = 0
    Thread.list.each do |t|
      thread_count += 1
      err_msg += "--- thread #{thread_count} of total #{Thread.list.size} #{t.object_id} backtrace begin \n"
      # Lets see if we are able to pin down the culprit
      # by collecting backtrace for all existing threads:
      err_msg += t.backtrace.join("\n")
      err_msg += "\n---thread #{thread_count} of total #{Thread.list.size} #{t.object_id} backtrace end \n"

    # and just print it somewhere you like:

    raise # always reraise

The above code snippet is useful even just for educational purposes as it can show you (like x-ray) how many threads you actually have (versus how many you thought you have - quite often those two are different numbers ;)

How do I align views at the bottom of the screen?

You can do this with a LinearLayout or a ScrollView, too. Sometimes it is easier to implement than a RelativeLayout. The only thing you need to do is to add the following view before the Views you want to align to the bottom of the screen:

    android:layout_weight="1" />

This creates an empty view, filling the empty space and pushing the next views to the bottom of the screen.

How to get visitor's location (i.e. country) using geolocation?

A very easy to use service is provided by Here's an example URL:

And here's some (jQuery) code which I've added to your code:

if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function(position) {
        $.getJSON('', {
            lat: position.coords.latitude,
            lng: position.coords.longitude,
            type: 'JSON'
        }, function(result) {
            alert('Country: ' + result.countryName + '\n' + 'Code: ' + result.countryCode);

Try it on ...

logger configuration to log to file and print to stdout

Adding a StreamHandler without arguments goes to stderr instead of stdout. If some other process has a dependency on the stdout dump (i.e. when writing an NRPE plugin), then make sure to specify stdout explicitly or you might run into some unexpected troubles.

Here's a quick example reusing the assumed values and LOGFILE from the question:

import logging
from logging.handlers import RotatingFileHandler
from logging import handlers
import sys

log = logging.getLogger('')
format = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")

ch = logging.StreamHandler(sys.stdout)

fh = handlers.RotatingFileHandler(LOGFILE, maxBytes=(1048576*5), backupCount=7)

How can I remove space (margin) above HTML header?

To prevent unexpected margins and other browser-specific behavior in the future, I'd recommend to include reset.css in your stylesheets.

Be aware that you'll have to set the h[1..6] font size and weight to make headings look like headings again after that, and many other things.

Set cookie and get cookie with JavaScript

I find the following code to be much simpler than anything else:

function setCookie(name,value,days) {
    var expires = "";
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days*24*60*60*1000));
        expires = "; expires=" + date.toUTCString();
    document.cookie = name + "=" + (value || "")  + expires + "; path=/";
function getCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    return null;
function eraseCookie(name) {   
    document.cookie = name +'=; Path=/; Expires=Thu, 01 Jan 1970 00:00:01 GMT;';

Now, calling functions


var x = getCookie('ppkcookie');
if (x) {
    [do something with x]

Source -

They updated the page today so everything in the page should be latest as of now.

Getting Image from URL (Java)

This code worked fine for me.


public class SaveImageFromUrl {

public static void main(String[] args) throws Exception {
    String imageUrl = "";
    String destinationFile = "image.jpg";

    saveImage(imageUrl, destinationFile);

public static void saveImage(String imageUrl, String destinationFile) throws IOException {
    URL url = new URL(imageUrl);
    InputStream is = url.openStream();
    OutputStream os = new FileOutputStream(destinationFile);

    byte[] b = new byte[2048];
    int length;

    while ((length = != -1) {
        os.write(b, 0, length);