Programs & Examples On #Mesh

A polygon mesh or unstructured grid is a collection of vertices, edges and faces that defines the shape of a polyhedral object in 3D computer graphics and solid modeling.

What is the purpose of meshgrid in Python / NumPy?

The purpose of meshgrid is to create a rectangular grid out of an array of x values and an array of y values.

So, for example, if we want to create a grid where we have a point at each integer value between 0 and 4 in both the x and y directions. To create a rectangular grid, we need every combination of the x and y points.

This is going to be 25 points, right? So if we wanted to create an x and y array for all of these points, we could do the following.

x[0,0] = 0    y[0,0] = 0
x[0,1] = 1    y[0,1] = 0
x[0,2] = 2    y[0,2] = 0
x[0,3] = 3    y[0,3] = 0
x[0,4] = 4    y[0,4] = 0
x[1,0] = 0    y[1,0] = 1
x[1,1] = 1    y[1,1] = 1
...
x[4,3] = 3    y[4,3] = 4
x[4,4] = 4    y[4,4] = 4

This would result in the following x and y matrices, such that the pairing of the corresponding element in each matrix gives the x and y coordinates of a point in the grid.

x =   0 1 2 3 4        y =   0 0 0 0 0
      0 1 2 3 4              1 1 1 1 1
      0 1 2 3 4              2 2 2 2 2
      0 1 2 3 4              3 3 3 3 3
      0 1 2 3 4              4 4 4 4 4

We can then plot these to verify that they are a grid:

plt.plot(x,y, marker='.', color='k', linestyle='none')

enter image description here

Obviously, this gets very tedious especially for large ranges of x and y. Instead, meshgrid can actually generate this for us: all we have to specify are the unique x and y values.

xvalues = np.array([0, 1, 2, 3, 4]);
yvalues = np.array([0, 1, 2, 3, 4]);

Now, when we call meshgrid, we get the previous output automatically.

xx, yy = np.meshgrid(xvalues, yvalues)

plt.plot(xx, yy, marker='.', color='k', linestyle='none')

enter image description here

Creation of these rectangular grids is useful for a number of tasks. In the example that you have provided in your post, it is simply a way to sample a function (sin(x**2 + y**2) / (x**2 + y**2)) over a range of values for x and y.

Because this function has been sampled on a rectangular grid, the function can now be visualized as an "image".

enter image description here

Additionally, the result can now be passed to functions which expect data on rectangular grid (i.e. contourf)

Delete column from pandas DataFrame

If your original dataframe df is not too big, you have no memory constraints, and you only need to keep a few columns, or, if you don't know beforehand the names of all the extra columns that you do not need, then you might as well create a new dataframe with only the columns you need:

new_df = df[['spam', 'sausage']]

Simple way to query connected USB devices info in Python?

If you are working on windows, you can use pywin32 (old link: see update below).

I found an example here:

import win32com.client

wmi = win32com.client.GetObject ("winmgmts:")
for usb in wmi.InstancesOf ("Win32_USBHub"):
    print usb.DeviceID

Update Apr 2020:

'pywin32' release versions from 218 and up can be found here at github. Current version 227.

Telegram Bot - how to get a group chat id?

IMHO the best way to do this is using TeleThon, but given that the answer by apadana is outdated beyond repair, I will write the working solution here:

import os
import sys
from telethon import TelegramClient
from telethon.utils import get_display_name

import nest_asyncio
nest_asyncio.apply()

session_name = "<session_name>"
api_id = <api_id>
api_hash = "<api_hash>"
dialog_count = 10 # you may change this

if f"{session_name}.session" in os.listdir():
    os.remove(f"{session_name}.session")

client = TelegramClient(session_name, api_id, api_hash)

async def main():
    dialogs = await client.get_dialogs(dialog_count)
    for dialog in dialogs:
        print(get_display_name(dialog.entity), dialog.entity.id)

async with client:
    client.loop.run_until_complete(main())

this snippet will give you the first 10 chats in your Telegram.

Assumptions:

  • you have telethon and nest_asyncio installed
  • you have api_id and api_hash from my.telegram.org

How can I check if an array contains a specific value in php?

See in_array

<?php
    $arr = array(0 => "kitchen", 1 => "bedroom", 2 => "living_room", 3 => "dining_room");    
    if (in_array("kitchen", $arr))
    {
        echo sprintf("'kitchen' is in '%s'", implode(', ', $arr));
    }
?>

JavaScript - Use variable in string match

You have to use RegExp object if your pattern is string

var xxx = "victoria";
var yyy = "i";
var rgxp = new RegExp(yyy, "g");
alert(xxx.match(rgxp).length);

If pattern is not dynamic string:

var xxx = "victoria";
var yyy = /i/g;
alert(xxx.match(yyy).length);

Send values from one form to another form

You can use this;

Form1 button1 click

private void button1_Click(object sender, EventArgs e)
{
    Form2 frm2 = new Form2();
    this.Hide();
    frm2.Show();
}

And add this to Form2

public string info = "";

Form2 button1 click

private void button1_Click(object sender, EventArgs e)
{

    info = textBox1.Text;
    this.Hide();
    BeginInvoke(new MethodInvoker(() =>
    {
        Gogo();
    }));
}

public void Gogo()
{
    Form1 frm = new Form1();
    frm.Show();
    frm.Text = info;
}

How to disable a particular checkstyle rule for a particular line of code?

Check out the use of the supressionCommentFilter at http://checkstyle.sourceforge.net/config_filters.html#SuppressionCommentFilter. You'll need to add the module to your checkstyle.xml

<module name="SuppressionCommentFilter"/>

and it's configurable. Thus you can add comments to your code to turn off checkstyle (at various levels) and then back on again through the use of comments in your code. E.g.

//CHECKSTYLE:OFF
public void someMethod(String arg1, String arg2, String arg3, String arg4) {
//CHECKSTYLE:ON

Or even better, use this more tweaked version:

<module name="SuppressionCommentFilter">
    <property name="offCommentFormat" value="CHECKSTYLE.OFF\: ([\w\|]+)"/>
    <property name="onCommentFormat" value="CHECKSTYLE.ON\: ([\w\|]+)"/>
    <property name="checkFormat" value="$1"/>
</module>

which allows you to turn off specific checks for specific lines of code:

//CHECKSTYLE.OFF: IllegalCatch - Much more readable than catching 7 exceptions
catch (Exception e)
//CHECKSTYLE.ON: IllegalCatch

*Note: you'll also have to add the FileContentsHolder:

<module name="FileContentsHolder"/>

See also

<module name="SuppressionFilter">
    <property name="file" value="docs/suppressions.xml"/>
</module>

under the SuppressionFilter section on that same page, which allows you to turn off individual checks for pattern matched resources.

So, if you have in your checkstyle.xml:

<module name="ParameterNumber">
   <property name="id" value="maxParameterNumber"/>
   <property name="max" value="3"/>
   <property name="tokens" value="METHOD_DEF"/>
</module>

You can turn it off in your suppression xml file with:

<suppress id="maxParameterNumber" files="YourCode.java"/>

Another method, now available in Checkstyle 5.7 is to suppress violations via the @SuppressWarnings java annotation. To do this, you will need to add two new modules (SuppressWarningsFilter and SuppressWarningsHolder) in your configuration file:

<module name="Checker">
   ...
   <module name="SuppressWarningsFilter" />
   <module name="TreeWalker">
       ...
       <module name="SuppressWarningsHolder" />
   </module>
</module> 

Then, within your code you can do the following:

@SuppressWarnings("checkstyle:methodlength")
public void someLongMethod() throws Exception {

or, for multiple suppressions:

@SuppressWarnings({"checkstyle:executablestatementcount", "checkstyle:methodlength"})
public void someLongMethod() throws Exception {

NB: The "checkstyle:" prefix is optional (but recommended). According to the docs the parameter name have to be in all lowercase, but practice indicates any case works.

How can I get phone serial number (IMEI)

public String getIMEI(Context context){

    TelephonyManager mngr = (TelephonyManager) context.getSystemService(context.TELEPHONY_SERVICE); 
    String imei = mngr.getDeviceId();
    return imei;

}

How can I draw vertical text with CSS cross-browser?

Updated this answer with recent information (from CSS Tricks). Kudos to Matt and Douglas for pointing out the filter implementation.

.rotate {
  -webkit-transform: rotate(-90deg);
  -moz-transform: rotate(-90deg);
  -ms-transform: rotate(-90deg);
  -o-transform: rotate(-90deg);
  transform: rotate(-90deg);

  /* also accepts left, right, top, bottom coordinates; not required, but a good idea for styling */
  -webkit-transform-origin: 50% 50%;
  -moz-transform-origin: 50% 50%;
  -ms-transform-origin: 50% 50%;
  -o-transform-origin: 50% 50%;
  transform-origin: 50% 50%;

  /* Should be unset in IE9+ I think. */
  filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=3);
}

Old answer:

For FF 3.5 or Safari/Webkit 3.1, check out: -moz-transform (and -webkit-transform). IE has a Matrix filter(v5.5+), but I'm not certain how to use it. Opera has no transformation capabilities yet.

.rot-neg-90 {
  /* rotate -90 deg, not sure if a negative number is supported so I used 270 */
  -moz-transform: rotate(270deg);
  -moz-transform-origin: 50% 50%;
  -webkit-transform: rotate(270deg);
  -webkit-transform-origin: 50% 50%;
  /* IE support too convoluted for the time I've got on my hands... */
}

How to do fade-in and fade-out with JavaScript and CSS

I think i get the problem :

Once you make the div fade out you aren't exiting the function : fadeout calls itself again over even after opacity has become 0

if(element.style.opacity < 0.0) {
            return;
        } 

And do the same for fadein too

Changing a specific column name in pandas DataFrame

A one liner does exist:

In [27]: df=df.rename(columns = {'two':'new_name'})

In [28]: df
Out[28]: 
  one three  new_name
0    1     a         9
1    2     b         8
2    3     c         7
3    4     d         6
4    5     e         5

Following is the docstring for the rename method.

Definition: df.rename(self, index=None, columns=None, copy=True, inplace=False)
Docstring:
Alter index and / or columns using input function or
functions. Function / dict values must be unique (1-to-1). Labels not
contained in a dict / Series will be left as-is.

Parameters
----------
index : dict-like or function, optional
    Transformation to apply to index values
columns : dict-like or function, optional
    Transformation to apply to column values
copy : boolean, default True
    Also copy underlying data
inplace : boolean, default False
    Whether to return a new DataFrame. If True then value of copy is
    ignored.

See also
--------
Series.rename

Returns
-------
renamed : DataFrame (new object)

Android map v2 zoom to show all the markers

Use the method "getCenterCoordinate" to obtain the center coordinate and use in CameraPosition.

private void setUpMap() {
    mMap.setMyLocationEnabled(true);
    mMap.getUiSettings().setScrollGesturesEnabled(true);
    mMap.getUiSettings().setTiltGesturesEnabled(true);
    mMap.getUiSettings().setRotateGesturesEnabled(true);

    clientMarker = mMap.addMarker(new MarkerOptions()
            .position(new LatLng(Double.valueOf(-12.1024174), Double.valueOf(-77.0262274)))
            .icon(BitmapDescriptorFactory.fromResource(R.mipmap.ic_taxi))
    );
    clientMarker = mMap.addMarker(new MarkerOptions()
            .position(new LatLng(Double.valueOf(-12.1024637), Double.valueOf(-77.0242617)))
            .icon(BitmapDescriptorFactory.fromResource(R.mipmap.ic_location))
    );

    camPos = new CameraPosition.Builder()
            .target(getCenterCoordinate())
            .zoom(17)
            .build();
    camUpd3 = CameraUpdateFactory.newCameraPosition(camPos);
    mMap.animateCamera(camUpd3);
}


public LatLng getCenterCoordinate(){
    LatLngBounds.Builder builder = new LatLngBounds.Builder();
    builder.include(new LatLng(Double.valueOf(-12.1024174), Double.valueOf(-77.0262274)));
    builder.include(new LatLng(Double.valueOf(-12.1024637), Double.valueOf(-77.0242617)));
    LatLngBounds bounds = builder.build();
    return bounds.getCenter();
}

What is default list styling (CSS)?

I think this is actually what you're looking for:

.my_container ul
{
    list-style: initial;
    margin: initial;
    padding: 0 0 0 40px;
}

.my_container li
{
    display: list-item;
}

How can I pass a Bitmap object from one activity to another

Bitmap implements Parcelable, so you could always pass it with the intent:

Intent intent = new Intent(this, NewActivity.class);
intent.putExtra("BitmapImage", bitmap);

and retrieve it on the other end:

Intent intent = getIntent(); 
Bitmap bitmap = (Bitmap) intent.getParcelableExtra("BitmapImage");

Version vs build in Xcode

The Build number is an internal number that indicates the current state of the app. It differs from the Version number in that it's typically not user facing and doesn't denote any difference/features/upgrades like a version number typically would.

Think of it like this:

  • Build (CFBundleVersion): The number of the build. Usually you start this at 1 and increase by 1 with each build of the app. It quickly allows for comparisons of which build is more recent and it denotes the sense of progress of the codebase. These can be overwhelmingly valuable when working with QA and needing to be sure bugs are logged against the right builds.
  • Marketing Version (CFBundleShortVersionString): The user-facing number you are using to denote this version of your app. Usually this follows a Major.minor version scheme (e.g. MyAwesomeApp 1.2) to let users know which releases are smaller maintenance updates and which are big deal new features.

To use this effectively in your projects, Apple provides a great tool called agvtool. I highly recommend using this as it is MUCH more simple than scripting up plist changes. It allows you to easily set both the build number and the marketing version. It is particularly useful when scripting (for instance, easily updating the build number on each build or even querying what the current build number is). It can even do more exotic things like tag your SVN for you when you update the build number.

To use it:

  • Set your project in Xcode, under Versioning, to use "Apple Generic".
  • In terminal
    • agvtool new-version 1 (set the Build number to 1)
    • agvtool new-marketing-version 1.0 (set the Marketing version to 1.0)

See the man page of agvtool for a ton of good info

How do I make a Docker container start automatically on system boot?

You can run a container that restart always by:

$ docker run -dit --restart unless-stopped <image name OR image hash>

If you want to change a running container's configs, you should update it by:

$ docker update --restart=<options> <container ID OR name>

And if you want to see current policy of the container, run the following command before above at the first place:

docker inspect gateway | grep RestartPolicy -A 3

After all, Not to forget to make installed docker daemon enable at system boot by:

$ systemctl enable docker

To see a full list of restart policies, see: Restart Policies

How to position a CSS triangle using ::after?

You can set triangle with position see this code for reference

.top-left-corner {
    width: 0px;
    height: 0px;
    border-top: 0px solid transparent;
    border-bottom: 55px solid transparent;
    border-left: 55px solid #289006;
    position: absolute;
    left: 0px;
    top: 0px;
}

Get ConnectionString from appsettings.json instead of being hardcoded in .NET Core 2.0 App

There is actually a default pattern that you can employ to achieve this result without having to implement IDesignTimeDbContextFactory and do any config file copying.

It is detailed in this doc, which also discusses the other ways in which the framework will attempt to instantiate your DbContext at design time.

Specifically, you leverage a new hook, in this case a static method of the form public static IWebHost BuildWebHost(string[] args). The documentation implies otherwise, but this method can live in whichever class houses your entry point (see src). Implementing this is part of the guidance in the 1.x to 2.x migration document and what's not completely obvious looking at the code is that the call to WebHost.CreateDefaultBuilder(args) is, among other things, connecting your configuration in the default pattern that new projects start with. That's all you need to get the configuration to be used by the design time services like migrations.

Here's more detail on what's going on deep down in there:

While adding a migration, when the framework attempts to create your DbContext, it first adds any IDesignTimeDbContextFactory implementations it finds to a collection of factory methods that can be used to create your context, then it gets your configured services via the static hook discussed earlier and looks for any context types registered with a DbContextOptions (which happens in your Startup.ConfigureServices when you use AddDbContext or AddDbContextPool) and adds those factories. Finally, it looks through the assembly for any DbContext derived classes and creates a factory method that just calls Activator.CreateInstance as a final hail mary.

The order of precedence that the framework uses is the same as above. Thus, if you have IDesignTimeDbContextFactory implemented, it will override the hook mentioned above. For most common scenarios though, you won't need IDesignTimeDbContextFactory.

Focus Input Box On Load

$(document).ready(function() {
    $('#id').focus();
});

HintPath vs ReferencePath in Visual Studio

According to this MSDN blog: https://blogs.msdn.microsoft.com/manishagarwal/2005/09/28/resolving-file-references-in-team-build-part-2/

There is a search order for assemblies when building. The search order is as follows:

  • Files from the current project – indicated by ${CandidateAssemblyFiles}.
  • $(ReferencePath) property that comes from .user/targets file.
  • %(HintPath) metadata indicated by reference item.
  • Target framework directory.
  • Directories found in registry that uses AssemblyFoldersEx Registration.
  • Registered assembly folders, indicated by ${AssemblyFolders}.
  • $(OutputPath) or $(OutDir)
  • GAC

So, if the desired assembly is found by HintPath, but an alternate assembly can be found using ReferencePath, it will prefer the ReferencePath'd assembly to the HintPath'd one.

Java how to replace 2 or more spaces with single space in string and delete leading and trailing spaces

String Tokenizer can be used

 String str = "  hello    there  ";
            StringTokenizer stknzr = new StringTokenizer(str, " ");
            StringBuffer sb = new StringBuffer();
            while(stknzr.hasMoreElements())
            {
                sb.append(stknzr.nextElement()).append(" ");
            }
            System.out.println(sb.toString().trim());

Why doesn't Java offer operator overloading?

While the Java language does not directly support operator overloading, you can use the Manifold compiler plugin in any Java project to enable it. It supports Java 8 - 13 (the current Java version) and is fully supported in IntelliJ IDEA.

Android "gps requires ACCESS_FINE_LOCATION" error, even though my manifest file contains this

ACCESS_COARSE_LOCATION, ACCESS_FINE_LOCATION, and WRITE_EXTERNAL_STORAGE are all part of the Android 6.0 runtime permission system. In addition to having them in the manifest as you do, you also have to request them from the user at runtime (using requestPermissions()) and see if you have them (using checkSelfPermission()).

One workaround in the short term is to drop your targetSdkVersion below 23.

But, eventually, you will want to update your app to use the runtime permission system.

For example, this activity works with five permissions. Four are runtime permissions, though it is presently only handling three (I wrote it before WRITE_EXTERNAL_STORAGE was added to the runtime permission roster).

/***
 Copyright (c) 2015 CommonsWare, LLC
 Licensed under the Apache License, Version 2.0 (the "License"); you may not
 use this file except in compliance with the License. You may obtain a copy
 of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
 by applicable law or agreed to in writing, software distributed under the
 License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
 OF ANY KIND, either express or implied. See the License for the specific
 language governing permissions and limitations under the License.

 From _The Busy Coder's Guide to Android Development_
 https://commonsware.com/Android
 */

package com.commonsware.android.permmonger;

import android.Manifest;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
  private static final String[] INITIAL_PERMS={
    Manifest.permission.ACCESS_FINE_LOCATION,
    Manifest.permission.READ_CONTACTS
  };
  private static final String[] CAMERA_PERMS={
    Manifest.permission.CAMERA
  };
  private static final String[] CONTACTS_PERMS={
      Manifest.permission.READ_CONTACTS
  };
  private static final String[] LOCATION_PERMS={
      Manifest.permission.ACCESS_FINE_LOCATION
  };
  private static final int INITIAL_REQUEST=1337;
  private static final int CAMERA_REQUEST=INITIAL_REQUEST+1;
  private static final int CONTACTS_REQUEST=INITIAL_REQUEST+2;
  private static final int LOCATION_REQUEST=INITIAL_REQUEST+3;
  private TextView location;
  private TextView camera;
  private TextView internet;
  private TextView contacts;
  private TextView storage;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    location=(TextView)findViewById(R.id.location_value);
    camera=(TextView)findViewById(R.id.camera_value);
    internet=(TextView)findViewById(R.id.internet_value);
    contacts=(TextView)findViewById(R.id.contacts_value);
    storage=(TextView)findViewById(R.id.storage_value);

    if (!canAccessLocation() || !canAccessContacts()) {
      requestPermissions(INITIAL_PERMS, INITIAL_REQUEST);
    }
  }

  @Override
  protected void onResume() {
    super.onResume();

    updateTable();
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.actions, menu);

    return(super.onCreateOptionsMenu(menu));
  }

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()) {
      case R.id.camera:
        if (canAccessCamera()) {
          doCameraThing();
        }
        else {
          requestPermissions(CAMERA_PERMS, CAMERA_REQUEST);
        }
        return(true);

      case R.id.contacts:
        if (canAccessContacts()) {
          doContactsThing();
        }
        else {
          requestPermissions(CONTACTS_PERMS, CONTACTS_REQUEST);
        }
        return(true);

      case R.id.location:
        if (canAccessLocation()) {
          doLocationThing();
        }
        else {
          requestPermissions(LOCATION_PERMS, LOCATION_REQUEST);
        }
        return(true);
    }

    return(super.onOptionsItemSelected(item));
  }

  @Override
  public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    updateTable();

    switch(requestCode) {
      case CAMERA_REQUEST:
        if (canAccessCamera()) {
          doCameraThing();
        }
        else {
          bzzzt();
        }
        break;

      case CONTACTS_REQUEST:
        if (canAccessContacts()) {
          doContactsThing();
        }
        else {
          bzzzt();
        }
        break;

      case LOCATION_REQUEST:
        if (canAccessLocation()) {
          doLocationThing();
        }
        else {
          bzzzt();
        }
        break;
    }
  }

  private void updateTable() {
    location.setText(String.valueOf(canAccessLocation()));
    camera.setText(String.valueOf(canAccessCamera()));
    internet.setText(String.valueOf(hasPermission(Manifest.permission.INTERNET)));
    contacts.setText(String.valueOf(canAccessContacts()));
    storage.setText(String.valueOf(hasPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE)));
  }

  private boolean canAccessLocation() {
    return(hasPermission(Manifest.permission.ACCESS_FINE_LOCATION));
  }

  private boolean canAccessCamera() {
    return(hasPermission(Manifest.permission.CAMERA));
  }

  private boolean canAccessContacts() {
    return(hasPermission(Manifest.permission.READ_CONTACTS));
  }

  private boolean hasPermission(String perm) {
    return(PackageManager.PERMISSION_GRANTED==checkSelfPermission(perm));
  }

  private void bzzzt() {
    Toast.makeText(this, R.string.toast_bzzzt, Toast.LENGTH_LONG).show();
  }

  private void doCameraThing() {
    Toast.makeText(this, R.string.toast_camera, Toast.LENGTH_SHORT).show();
  }

  private void doContactsThing() {
    Toast.makeText(this, R.string.toast_contacts, Toast.LENGTH_SHORT).show();
  }

  private void doLocationThing() {
    Toast.makeText(this, R.string.toast_location, Toast.LENGTH_SHORT).show();
  }
}

(from this sample project)

For the requestPermissions() function, should the parameters just be "ACCESS_COARSE_LOCATION"? Or should I include the full name "android.permission.ACCESS_COARSE_LOCATION"?

I would use the constants defined on Manifest.permission, as shown above.

Also, what is the request code?

That will be passed back to you as the first parameter to onRequestPermissionsResult(), so you can tell one requestPermissions() call from another.

How to view the dependency tree of a given npm module?

View All the metadata about npm module

npm view mongoose(module name)

View All Dependencies of module

npm view mongoose dependencies

View All Version or Versions module

npm view mongoose version
npm view mongoose versions

View All the keywords

npm view mongoose keywords

How to remove all event handlers from an event

I found a solution on the MSDN forums. The sample code below will remove all Click events from button1.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        button1.Click += button1_Click;
        button1.Click += button1_Click2;
        button2.Click += button2_Click;
    }

    private void button1_Click(object sender, EventArgs e)  => MessageBox.Show("Hello");
    private void button1_Click2(object sender, EventArgs e) => MessageBox.Show("World");
    private void button2_Click(object sender, EventArgs e)  => RemoveClickEvent(button1);

    private void RemoveClickEvent(Button b)
    {
        FieldInfo f1 = typeof(Control).GetField("EventClick", 
            BindingFlags.Static | BindingFlags.NonPublic);

        object obj = f1.GetValue(b);
        PropertyInfo pi = b.GetType().GetProperty("Events",  
            BindingFlags.NonPublic | BindingFlags.Instance);

        EventHandlerList list = (EventHandlerList)pi.GetValue(b, null);
        list.RemoveHandler(obj, list[obj]);
    }
}

jQuery Data vs Attr?

The main difference between the two is where it is stored and how it is accessed.

$.fn.attr stores the information directly on the element in attributes which are publicly visible upon inspection, and also which are available from the element's native API.

$.fn.data stores the information in a ridiculously obscure place. It is located in a closed over local variable called data_user which is an instance of a locally defined function Data. This variable is not accessible from outside of jQuery directly.

Data set with attr()

  • accessible from $(element).attr('data-name')
  • accessible from element.getAttribute('data-name'),
  • if the value was in the form of data-name also accessible from $(element).data(name) and element.dataset['name'] and element.dataset.name
  • visible on the element upon inspection
  • cannot be objects

Data set with .data()

  • accessible only from .data(name)
  • not accessible from .attr() or anywhere else
  • not publicly visible on the element upon inspection
  • can be objects

What is the difference between Serialization and Marshaling?

Marshalling is the rule to tell compiler how the data will be represented on another environment/system; For example;

[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
public string cFileName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
public string cAlternateFileName;

as you can see two different string values represented as different value types.

Serialization will only convert object content, not representation (will stay same) and obey rules of serialization, (what to export or no). For example, private values will not be serialized, public values yes and object structure will stay same.

How can I replace every occurrence of a String in a file with PowerShell?

If You Need to Replace Strings in Multiple Files:

It should be noted that the different methods posted here can be wildly different with regard to the time it takes to complete. For me, I regularly have large numbers of small files. To test what is most performant, I extracted 5.52 GB (5,933,604,999 bytes) of XML in 40,693 separate files and ran through three of the answers I found here:

## 5.52 GB (5,933,604,999 bytes) of XML files (40,693 files) 

#### Test 1 - Plain Replace
$start = get-date
$xmls = (Get-ChildItem -Path "I:\TestseT\All_XML" -Recurse -Filter *.xml).FullName
foreach ($xml in $xmls)
{
(Get-Content $xml).replace("'", " ") | Set-Content $xml
}
$end   = get-date
NEW-TIMESPAN –Start $Start –End $End
<#
TotalMinutes: 103.725113128333
#>

#### Test 2 - Replace with -Raw
$start = get-date
$xmls = (Get-ChildItem -Path "I:\TestseT\All_XML" -Recurse -Filter *.xml).FullName
foreach ($xml in $xmls)
{
(Get-Content $xml -Raw).replace("'", " ") | Set-Content $xml
}
$end   = get-date
NEW-TIMESPAN –Start $Start –End $End
<#
TotalMinutes: 10.1600227983333
#>

#### Test 3 - .NET, System.IO
$start = get-date
$xmls = (Get-ChildItem -Path "I:\TestseT\All_XML" -Recurse -Filter *.xml).FullName
foreach ($xml in $xmls)
{
$txt = [System.IO.File]::ReadAllText("$xml").Replace("'"," ") 
[System.IO.File]::WriteAllText("$xml", $txt)
}
$end   = get-date
NEW-TIMESPAN –Start $Start –End $End
<#
TotalMinutes: 5.83619516833333
#>

How can I select random files from a directory in bash?

This is the only script I can get to play nice with bash on MacOS. I combined and edited snippets from the following two links:

ls command: how can I get a recursive full-path listing, one line per file?

http://www.linuxquestions.org/questions/linux-general-1/is-there-a-bash-command-for-picking-a-random-file-678687/

#!/bin/bash

# Reads a given directory and picks a random file.

# The directory you want to use. You could use "$1" instead if you
# wanted to parametrize it.
DIR="/path/to/"
# DIR="$1"

# Internal Field Separator set to newline, so file names with
# spaces do not break our script.
IFS='
'

if [[ -d "${DIR}" ]]
then
  # Runs ls on the given dir, and dumps the output into a matrix,
  # it uses the new lines character as a field delimiter, as explained above.
  #  file_matrix=($(ls -LR "${DIR}"))

  file_matrix=($(ls -R $DIR | awk '; /:$/&&f{s=$0;f=0}; /:$/&&!f{sub(/:$/,"");s=$0;f=1;next}; NF&&f{ print s"/"$0 }'))
  num_files=${#file_matrix[*]}

  # This is the command you want to run on a random file.
  # Change "ls -l" by anything you want, it's just an example.
  ls -l "${file_matrix[$((RANDOM%num_files))]}"
fi

exit 0

How do I convert this list of dictionaries to a csv file?

import csv
toCSV = [{'name':'bob','age':25,'weight':200},
         {'name':'jim','age':31,'weight':180}]
header=['name','age','weight']     
try:
   with open('output'+str(date.today())+'.csv',mode='w',encoding='utf8',newline='') as output_to_csv:
       dict_csv_writer = csv.DictWriter(output_to_csv, fieldnames=header,dialect='excel')
       dict_csv_writer.writeheader()
       dict_csv_writer.writerows(toCSV)
   print('\nData exported to csv succesfully and sample data')
except IOError as io:
    print('\n',io)

Angular: Can't find Promise, Map, Set and Iterator

I am training with a angular2 tutorial(hero).
After installing @types/core-js commented in theses answers, I got a "Duplicate identifier" error.
In my case, it was solved as removing lib line in tsconfig.json.

//"lib": [ "es2015", "dom" ]

How to unzip files programmatically in Android?

The Kotlin way

//FileExt.kt

data class ZipIO (val entry: ZipEntry, val output: File)

fun File.unzip(unzipLocationRoot: File? = null) {

    val rootFolder = unzipLocationRoot ?: File(parentFile.absolutePath + File.separator + nameWithoutExtension)
    if (!rootFolder.exists()) {
       rootFolder.mkdirs()
    }

    ZipFile(this).use { zip ->
        zip
        .entries()
        .asSequence()
        .map {
            val outputFile = File(rootFolder.absolutePath + File.separator + it.name)
            ZipIO(it, outputFile)
        }
        .map {
            it.output.parentFile?.run{
                if (!exists()) mkdirs()
            }
            it
        }
        .filter { !it.entry.isDirectory }
        .forEach { (entry, output) ->
            zip.getInputStream(entry).use { input ->
                output.outputStream().use { output ->
                    input.copyTo(output)
                }
            }
        }
    }

}

Usage

val zipFile = File("path_to_your_zip_file")
file.unzip()

How to clear input buffer in C?

The lines:

int ch;
while ((ch = getchar()) != '\n' && ch != EOF)
    ;

doesn't read only the characters before the linefeed ('\n'). It reads all the characters in the stream (and discards them) up to and including the next linefeed (or EOF is encountered). For the test to be true, it has to read the linefeed first; so when the loop stops, the linefeed was the last character read, but it has been read.

As for why it reads a linefeed instead of a carriage return, that's because the system has translated the return to a linefeed. When enter is pressed, that signals the end of the line... but the stream contains a line feed instead since that's the normal end-of-line marker for the system. That might be platform dependent.

Also, using fflush() on an input stream doesn't work on all platforms; for example it doesn't generally work on Linux.

What is the right way to debug in iPython notebook?

The %pdb magic command is good to use as well. Just say %pdb on and subsequently the pdb debugger will run on all exceptions, no matter how deep in the call stack. Very handy.

If you have a particular line that you want to debug, just raise an exception there (often you already are!) or use the %debug magic command that other folks have been suggesting.

How to change the MySQL root account password on CentOS7?

What version of mySQL are you using? I''m using 5.7.10 and had the same problem with logging on as root

There is 2 issues - why can't I log in as root to start with, and why can I not use 'mysqld_safe` to start mySQL to reset the root password.

I have no answer to setting up the root password during installation, but here's what you do to reset the root password

Edit the initial root password on install can be found by running

grep 'temporary password' /var/log/mysqld.log

http://dev.mysql.com/doc/refman/5.7/en/linux-installation-yum-repo.html


  1. systemd is now used to look after mySQL instead of mysqld_safe (which is why you get the -bash: mysqld_safe: command not found error - it's not installed)

  2. The user table structure has changed.

So to reset the root password, you still start mySQL with --skip-grant-tables options and update the user table, but how you do it has changed.

1. Stop mysql:
systemctl stop mysqld

2. Set the mySQL environment option 
systemctl set-environment MYSQLD_OPTS="--skip-grant-tables"

3. Start mysql usig the options you just set
systemctl start mysqld

4. Login as root
mysql -u root

5. Update the root user password with these mysql commands
mysql> UPDATE mysql.user SET authentication_string = PASSWORD('MyNewPassword')
    -> WHERE User = 'root' AND Host = 'localhost';
mysql> FLUSH PRIVILEGES;
mysql> quit

*** Edit ***
As mentioned my shokulei in the comments, for 5.7.6 and later, you should use 
   mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';
Or you'll get a warning

6. Stop mysql
systemctl stop mysqld

7. Unset the mySQL envitroment option so it starts normally next time
systemctl unset-environment MYSQLD_OPTS

8. Start mysql normally:
systemctl start mysqld

Try to login using your new password:
7. mysql -u root -p

Reference

As it says at http://dev.mysql.com/doc/refman/5.7/en/mysqld-safe.html,

Note

As of MySQL 5.7.6, for MySQL installation using an RPM distribution, server startup and shutdown is managed by systemd on several Linux platforms. On these platforms, mysqld_safe is no longer installed because it is unnecessary. For more information, see Section 2.5.10, “Managing MySQL Server with systemd”.

Which takes you to http://dev.mysql.com/doc/refman/5.7/en/server-management-using-systemd.html where it mentions the systemctl set-environment MYSQLD_OPTS= towards the bottom of the page.

The password reset commands are at the bottom of http://dev.mysql.com/doc/refman/5.7/en/resetting-permissions.html

How to sort ArrayList<Long> in decreasing order?

Java 8

well doing this in java 8 is so much fun and easier

Collections.sort(variants,(a,b)->a.compareTo(b));
Collections.reverse(variants);

Lambda expressions rock here!!!

in case you needed a more than one line logic for comparing a and b you could write it like this

Collections.sort(variants,(a,b)->{
    int result = a.compareTo(b);
    return result;
});

Why javascript getTime() is not a function?

That's because your dat1 and dat2 variables are just strings.

You should parse them to get a Date object, for that format I always use the following function:

// parse a date in yyyy-mm-dd format
function parseDate(input) {
  var parts = input.match(/(\d+)/g);
  // new Date(year, month [, date [, hours[, minutes[, seconds[, ms]]]]])
  return new Date(parts[0], parts[1]-1, parts[2]); // months are 0-based
}

I use this function because the Date.parse(string) (or new Date(string)) method is implementation dependent, and the yyyy-MM-dd format will work on modern browser but not on IE, so I prefer doing it manually.

What's the difference between an Angular component and module

A module in Angular 2 is something which is made from components, directives, services etc. One or many modules combine to make an Application. Modules breakup application into logical pieces of code. Each module performs a single task.

Components in Angular 2 are classes where you write your logic for the page you want to display. Components control the view (html). Components communicate with other components and services.

Append file contents to the bottom of existing file in Bash

This should work:

 cat "$API" >> "$CONFIG"

You need to use the >> operator to append to a file. Redirecting with > causes the file to be overwritten. (truncated).

Undoing accidental git stash pop

Try using How to recover a dropped stash in Git? to find the stash you popped. I think there are always two commits for a stash, since it preserves the index and the working copy (so often the index commit will be empty). Then git show them to see the diff and use patch -R to unapply them.

How do I run Google Chrome as root?

It no longer suffices to start Chrome with --user-data-dir=/root/.config/google-chrome. It simply prints Aborted and ends (Chrome 48 on Ubuntu 12.04).

You need actually to run it as a non-root user. This you can do with

gksu -wu chrome-user google-chrome

where chrome-user is some user you've decided should be the one to run Chrome. Your Chrome user profile will be found at ~chrome-user/.config/google-chrome.

BTW, the old hack of changing all occurrences of geteuid to getppid in the chrome binary no longer works.

WARNING: Exception encountered during context initialization - cancelling refresh attempt

I was having the problem as a beginner..........

There was issue in the path of the xml file I have saved.

"id cannot be resolved or is not a field" error?

As Jake has mentioned, the problem might be because of copy/paste code. Check the main.xml under res/layout. If there is no id field in that then you have a problem. A typical example would be as below

<com.androidplot.xy.XYPlot
android:id="@+id/mySimpleXYPlot"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="10px"
android:layout_marginLeft="20px"
android:layout_marginRight="20px"
title="A Simple Example"
/>

How can I capture packets in Android?

Option 1 - Android PCAP

Limitation

Android PCAP should work so long as:

Your device runs Android 4.0 or higher (or, in theory, the few devices which run Android 3.2). Earlier versions of Android do not have a USB Host API

Option 2 - TcpDump

Limitation

Phone should be rooted

Option 3 - bitshark (I would prefer this)

Limitation

Phone should be rooted

Reason - the generated PCAP files can be analyzed in WireShark which helps us in doing the analysis.

Other Options without rooting your phone

  1. tPacketCapture

https://play.google.com/store/apps/details?id=jp.co.taosoftware.android.packetcapture&hl=en

Advantages

Using tPacketCapture is very easy, captured packet save into a PCAP file that can be easily analyzed by using a network protocol analyzer application such as Wireshark.

  1. You can route your android mobile traffic to PC and capture the traffic in the desktop using any network sniffing tool.

http://lifehacker.com/5369381/turn-your-windows-7-pc-into-a-wireless-hotspot

How do I install cURL on Windows?

Another answer for other people who have had this problem

when you un comment the extension line, change it to:

extension=C:/php/ext/php_curl.dll

or the location of the extension folder, for me it did not work until i did this

Add views in UIStackView programmatically

It is really not recommended to set a height constraint... If you can, never, never, never set a height! You need to check all the constraints of the views inside your UIStackView and be sure that there is constraints for bottom, top, leading and trailing. Someone said to me: it is like a guy pushing on walls. If he don't push on 4 sides, one of the wall will fall on him.

Print an integer in binary format in Java

I think it's the simplest algorithm so far (for those who don't want to use built-in functions):

public static String convertNumber(int a)  { 
              StringBuilder sb=new StringBuilder();
              sb.append(a & 1);
              while ((a>>=1) != 0)  { 
                  sb.append(a & 1);
               }
              sb.append("b0");
              return sb.reverse().toString();
  }

Example:

convertNumber(1) --> "0b1"

convertNumber(5) --> "0b101"

convertNumber(117) --> "0b1110101"

How it works: while-loop moves a-number to the right (replacing the last bit with second-to-last, etc), gets the last bit's value and puts it in StringBuilder, repeats until there are no bits left (that's when a=0).

AngularJs ReferenceError: $http is not defined

Just to complete Amit Garg answer, there are several ways to inject dependencies in AngularJS.


You can also use $inject to add a dependency:

var MyController = function($scope, $http) {
  // ...
}
MyController.$inject = ['$scope', '$http'];

Setting attribute disabled on a SPAN element does not prevent click events

The disabled attribute is not global and is only allowed on form controls. What you could do is set a custom data attribute (perhaps data-disabled) and check for that attribute when you handle the click event.

Escaping double quotes in JavaScript onClick event handler

You may also want to try two backslashes (\\") to escape the escape character.

What is a vertical tab?

I have found that the VT char is used in pptx text boxes at the end of each line shown in the box in oder to adjust the text to the size of the box. It seems to be automatically generated by powerpoint (not introduced by the user) in order to move the text to the next line and fix the complete text block to the text box. In the example below, in the position of §:

"This is a text §
inside a text box"

Request exceeded the limit of 10 internal redirects due to probable configuration error

//Just add 

RewriteBase /
//after 
RewriteEngine On

//and you are done....

//so it should be 

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [QSA,L]

How to set width of a p:column in a p:dataTable in PrimeFaces 3.0?

Inline styling would work in any case

  <p-column field="Quantity" header="Qté" [style]="{'width':'48px'}">

Expected corresponding JSX closing tag for input Reactjs

All tags must have enclosing tags. In my case, the hr and input elements weren't closed properly.

Parent Error was: JSX element 'div' has no corresponding closing tag, due to code below:

<hr class="my-4">
<input
  type="password"
  id="inputPassword"
  class="form-control"
  placeholder="Password"
  required
 >

Fix:

<hr class="my-4"/>
<input
 type="password"
 id="inputPassword"
 class="form-control"
 placeholder="Password"
 required
/>

The parent elements will show errors due to child element errors. Therefore, start investigating from most inner elements up to the parent ones.

jQuery on window resize

Use this:

window.onresize = function(event) {
    ...
}

database vs. flat files

Don't build it if you can buy it.

I heard this quote recently, and it really seems fitting as a guide line. Ask yourself this... How much time was spent working on the file handling portion of your app? I suspect a fair amount of time was spent optimizing this code for performance. If you had been using a relational database all along, you would have spent considerably less time handling this portion of your application. You would have had more time for the true "business" aspect of your app.

What is the purpose of willSet and didSet in Swift?

In your own (base) class, willSet and didSet are quite reduntant , as you could instead define a calculated property (i.e get- and set- methods) that access a _propertyVariable and does the desired pre- and post- prosessing.

If, however, you override a class where the property is already defined, then the willSet and didSet are useful and not redundant!

How to print a list of symbols exported from a dynamic library

Use nm -a your.dylib

It will print all the symbols including globals

Passing multiple variables to another page in url

You are checking isset($_GET['event_id'] but you've not set that get variable in your hyperlink, you are just adding email

http://localhost/main.php?email=" . $email_address . $event_id

And add another GET variable in your link

$url = "http://localhost/main.php?email=$email_address&event_id=$event_id";

You did not use to concatenate your string if you are using " quotes

Safe String to BigDecimal conversion

resultString = subjectString.replaceAll("[^.\\d]", "");

will remove all characters except digits and the dot from your string.

To make it locale-aware, you might want to use getDecimalSeparator() from java.text.DecimalFormatSymbols. I don't know Java, but it might look like this:

sep = getDecimalSeparator()
resultString = subjectString.replaceAll("[^"+sep+"\\d]", "");

CSS opacity only to background color, not the text on it?

The easiest way to do this is with 2 divs, 1 with the background and 1 with the text:

_x000D_
_x000D_
#container {_x000D_
  position: relative;_x000D_
  width: 300px;_x000D_
  height: 200px;_x000D_
}_x000D_
#block {_x000D_
  background: #CCC;_x000D_
  filter: alpha(opacity=60);_x000D_
  /* IE */_x000D_
  -moz-opacity: 0.6;_x000D_
  /* Mozilla */_x000D_
  opacity: 0.6;_x000D_
  /* CSS3 */_x000D_
  position: absolute;_x000D_
  top: 0;_x000D_
  left: 0;_x000D_
  height: 100%;_x000D_
  width: 100%;_x000D_
}_x000D_
#text {_x000D_
  position: absolute;_x000D_
  top: 0;_x000D_
  left: 0;_x000D_
  width: 100%;_x000D_
  height: 100%;_x000D_
}
_x000D_
<div id="container">_x000D_
  <div id="block"></div>_x000D_
  <div id="text">Test</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Commenting code in Notepad++

This link was exactly what I was searching for .

Let me summarize the answers for others' benefit (for python and notepad++)

1) Ctrl+K on multiple lines (i.e. selected region) allows you to block comment.

Also note that pressing the combination multiple times allows you to add multiple "#"s (sometimes I use that while testing to differentiate from other comments)

2) Ctrl+Shift+K (on the commented region) allows you to perform block uncomment

3) Ctrl+Shift+K on an uncommented selected region does not comment it

4) Ctrl+Q allows you to block comment/uncomment in a toggled mode (meaning, you cannot add multiple '#'s like in 1) )

Hope this helps another wandering soul.

Question - how would you develop a hack of keyboard combinations to comment/uncomment if there were no shortcuts? Just curious. I've no clue hence asking.

What is "String args[]"? parameter in main method Java

String[] args means an array of sequence of characters (Strings) that are passed to the "main" function. This happens when a program is executed.

Example when you execute a Java program via the command line:

java MyProgram This is just a test

Therefore, the array will store: ["This", "is", "just", "a", "test"]

How to split string using delimiter char using T-SQL?

You need a split function:

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
Create Function [dbo].[udf_Split]
(   
    @DelimitedList nvarchar(max)
    , @Delimiter nvarchar(2) = ','
)
RETURNS TABLE 
AS
RETURN 
    (
    With CorrectedList As
        (
        Select Case When Left(@DelimitedList, Len(@Delimiter)) <> @Delimiter Then @Delimiter Else '' End
            + @DelimitedList
            + Case When Right(@DelimitedList, Len(@Delimiter)) <> @Delimiter Then @Delimiter Else '' End
            As List
            , Len(@Delimiter) As DelimiterLen
        )
        , Numbers As 
        (
        Select TOP( Coalesce(DataLength(@DelimitedList)/2,0) ) Row_Number() Over ( Order By c1.object_id ) As Value
        From sys.columns As c1
            Cross Join sys.columns As c2
        )
    Select CharIndex(@Delimiter, CL.list, N.Value) + CL.DelimiterLen As Position
        , Substring (
                    CL.List
                    , CharIndex(@Delimiter, CL.list, N.Value) + CL.DelimiterLen     
                    , CharIndex(@Delimiter, CL.list, N.Value + 1)                           
                        - ( CharIndex(@Delimiter, CL.list, N.Value) + CL.DelimiterLen ) 
                    ) As Value
    From CorrectedList As CL
        Cross Join Numbers As N
    Where N.Value <= DataLength(CL.List) / 2
        And Substring(CL.List, N.Value, CL.DelimiterLen) = @Delimiter
    )

With your split function, you would then use Cross Apply to get the data:

Select T.Col1, T.Col2
    , Substring( Z.Value, 1, Charindex(' = ', Z.Value) - 1 ) As AttributeName
    , Substring( Z.Value, Charindex(' = ', Z.Value) + 1, Len(Z.Value) ) As Value
From Table01 As T
    Cross Apply dbo.udf_Split( T.Col3, '|' ) As Z

TypeScript: casting HTMLElement

Could be solved in the declaration file (lib.d.ts) if TypeScript would define HTMLCollection instead of NodeList as a return type.

DOM4 also specifies this as the correct return type, but older DOM specifications are less clear.

See also http://typescript.codeplex.com/workitem/252

Spark: Add column to dataframe conditionally

Try withColumn with the function when as follows:

val sqlContext = new SQLContext(sc)
import sqlContext.implicits._ // for `toDF` and $""
import org.apache.spark.sql.functions._ // for `when`

val df = sc.parallelize(Seq((4, "blah", 2), (2, "", 3), (56, "foo", 3), (100, null, 5)))
    .toDF("A", "B", "C")

val newDf = df.withColumn("D", when($"B".isNull or $"B" === "", 0).otherwise(1))

newDf.show() shows

+---+----+---+---+
|  A|   B|  C|  D|
+---+----+---+---+
|  4|blah|  2|  1|
|  2|    |  3|  0|
| 56| foo|  3|  1|
|100|null|  5|  0|
+---+----+---+---+

I added the (100, null, 5) row for testing the isNull case.

I tried this code with Spark 1.6.0 but as commented in the code of when, it works on the versions after 1.4.0.

Installing python module within code

import os
os.system('pip install requests')

I tried above for temporary solution instead of changing docker file. Hope these might be useful to some

Where is the IIS Express configuration / metabase file found?

For VS 2015 & VS 2017: Right-click the IIS Express system tray icon (when running the application), and select "Show all applications":

Context menu for IIS Express system tray icon showing the alternative "Show all applications" highlighted

Then, select the relevant application and click the applicationhost.config file path:

Dialog showing arbritrary website with accompanying applicationhost.config file path

how do I change text in a label with swift?

swift solution

yourlabel.text = yourvariable

or self is use for when you are in async {brackets} or in some Extension

DispatchQueue.main.async{
    self.yourlabel.text = "typestring"
}

How do I create a link using javascript?

With JavaScript

  1. var a = document.createElement('a');
    a.setAttribute('href',desiredLink);
    a.innerHTML = desiredText;
    // apend the anchor to the body
    // of course you can append it almost to any other dom element
    document.getElementsByTagName('body')[0].appendChild(a);
    
  2. document.getElementsByTagName('body')[0].innerHTML += '<a href="'+desiredLink+'">'+desiredText+'</a>';
    

    or, as suggested by @travis :

    document.getElementsByTagName('body')[0].innerHTML += desiredText.link(desiredLink);
    
  3. <script type="text/javascript">
    //note that this case can be used only inside the "body" element
    document.write('<a href="'+desiredLink+'">'+desiredText+'</a>');
    </script>
    

With JQuery

  1. $('<a href="'+desiredLink+'">'+desiredText+'</a>').appendTo($('body'));
    
  2. $('body').append($('<a href="'+desiredLink+'">'+desiredText+'</a>'));
    
  3. var a = $('<a />');
    a.attr('href',desiredLink);
    a.text(desiredText);
    $('body').append(a);
    

In all the above examples you can append the anchor to any element, not just to the 'body', and desiredLink is a variable that holds the address that your anchor element points to, and desiredText is a variable that holds the text that will be displayed in the anchor element.

How to create a List with a dynamic object type

Just use dynamic as the argument:

var list = new List<dynamic>();

Disable browser cache for entire ASP.NET website

UI

<%@ OutPutCache Location="None"%>
<%
    Response.Buffer = true;
    Response.Expires = -1;
    Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1);
    Response.CacheControl = "no-cache";
%>

Background

Context.Response.Cache.SetCacheability(HttpCacheability.NoCache); 
Response.Expires = -1;          
Response.Cache.SetNoStore();

Reset all changes after last commit in git

How can I undo every change made to my directory after the last commit, including deleting added files, resetting modified files, and adding back deleted files?

  1. You can undo changes to tracked files with:

    git reset HEAD --hard
    
  2. You can remove untracked files with:

    git clean -f
    
  3. You can remove untracked files and directories with:

    git clean -fd
    

    but you can't undo change to untracked files.

  4. You can remove ignored and untracked files and directories

    git clean -fdx
    

    but you can't undo change to ignored files.

You can also set clean.requireForce to false:

git config --global --add clean.requireForce false

to avoid using -f (--force) when you use git clean.

How do I tidy up an HTML file's indentation in VI?

Here's a heavy-weight solution that gets you indenting, plus all the HTML pretty-printing you don't necessarily want to care about while you're editing.

First, download Tidy. Make sure you add the binary to your path, so you can call it from any location.

Next, create a config file describing your favorite HTML flavor. Documentation is not great for Tidy, but here's an overview, and a list of all the options. Here's my config file:

bare: yes
break-before-br: no
clean: yes
drop-proprietary-attributes: yes
fix-uri: yes
indent-spaces: 4
indent: yes
logical-emphasis: yes
markup: yes
output-xhtml: yes
quiet: yes
quote-marks: yes
replace-color: yes
tab-size: 4
uppercase-tags: no
vertical-space: yes
word-2000: yes
wrap: 0

Save this as tidyrc_html.txt in your ftplugin folder (under vimfiles).

One more file: add the following line to (or create) html.vim, also in ftplugin:

map <leader>tidy :%! tidy -config ~/vimfiles/ftplugin/tidyrc_html.txt <CR>

To use it, just open an HTML file, and type /tidy. (That / is the <leader> key.)

There you go! Not a quick solution, by any means, but now you're a bit better equipped for editing those huge, messed-up HTML files.

Maven dependencies are failing with a 501 error

I have the same issue, but I use GitLab instead of Jenkins. The steps I had to do to get over the issue:

  1. My project is in GitLab so it uses the .yml file which points to a Docker image I have to do continuous integration, and the image it uses has the http://maven URLs. So I changed that to https://maven.
  2. That same Dockerfile image had an older version of Maven 3.0.1 that gave me issues just overnight. I updated the Dockerfile to get the latest version 3.6.3
  3. I then deployed that image to my online repository, and updated my Maven project ymlfile to use that new image.
  4. And lastly, I updated my main projects POM file to reference https://maven... instead of http://maven

I realize that is more specific to my setup. But without doing all of the steps above I would still continue to get this error message Return code is: 501 , ReasonPhrase:HTTPS Required

How do you copy a record in a SQL table but swap out the unique id of the new row?

Ok, I know that it's an old issue but I post my answer anyway.

I like this solution. I only have to specify the identity column(s).

SELECT * INTO TempTable FROM MyTable_T WHERE id = 1;
ALTER TABLE TempTable DROP COLUMN id;
INSERT INTO MyTable_T SELECT * FROM TempTable;
DROP TABLE TempTable;

The "id"-column is the identity column and that's the only column I have to specify. It's better than the other way around anyway. :-)

I use SQL Server. You may want to use "CREATE TABLE" and "UPDATE TABLE" at row 1 and 2. Hmm, I saw that I did not really give the answer that he wanted. He wanted to copy the id to another column also. But this solution is nice for making a copy with a new auto-id.

I edit my solution with the idéas from Michael Dibbets.

use MyDatabase; 
SELECT * INTO #TempTable FROM [MyTable] WHERE [IndexField] = :id;
ALTER TABLE #TempTable DROP COLUMN [IndexField]; 
INSERT INTO [MyTable] SELECT * FROM #TempTable; 
DROP TABLE #TempTable;

You can drop more than one column by separating them with a ",". The :id should be replaced with the id of the row you want to copy. MyDatabase, MyTable and IndexField should be replaced with your names (of course).

Why are C++ inline functions in the header?

This is a limit of the C++ compiler. If you put the function in the header, all the cpp files where it can be inlined can see the "source" of your function and the inlining can be done by the compiler. Otherwhise the inlining would have to be done by the linker (each cpp file is compiled in an obj file separately). The problem is that it would be much more difficult to do it in the linker. A similar problem exists with "template" classes/functions. They need to be instantiated by the compiler, because the linker would have problem instantiating (creating a specialized version of) them. Some newer compiler/linker can do a "two pass" compilation/linking where the compiler does a first pass, then the linker does its work and call the compiler to resolve unresolved things (inline/templates...)

The Use of Multiple JFrames: Good or Bad Practice?

I'm just wondering whether it is good practice to use multiple JFrames?

Bad (bad, bad) practice.

  • User unfriendly: The user sees multiple icons in their task bar when expecting to see only one. Plus the side effects of the coding problems..
  • A nightmare to code and maintain:
    • A modal dialog offers the easy opportunity to focus attention on the content of that dialog - choose/fix/cancel this, then proceed. Multiple frames do not.
    • A dialog (or floating tool-bar) with a parent will come to front when the parent is clicked on - you'd have to implement that in frames if that was the desired behavior.

There are any number of ways of displaying many elements in one GUI, e.g.:

  • CardLayout (short demo.). Good for:
    1. Showing wizard like dialogs.
    2. Displaying list, tree etc. selections for items that have an associated component.
    3. Flipping between no component and visible component.
  • JInternalFrame/JDesktopPane typically used for an MDI.
  • JTabbedPane for groups of components.
  • JSplitPane A way to display two components of which the importance between one or the other (the size) varies according to what the user is doing.
  • JLayeredPane far many well ..layered components.
  • JToolBar typically contains groups of actions or controls. Can be dragged around the GUI, or off it entirely according to user need. As mentioned above, will minimize/restore according to the parent doing so.
  • As items in a JList (simple example below).
  • As nodes in a JTree.
  • Nested layouts.

But if those strategies do not work for a particular use-case, try the following. Establish a single main JFrame, then have JDialog or JOptionPane instances appear for the rest of the free-floating elements, using the frame as the parent for the dialogs.

Many images

In this case where the multiple elements are images, it would be better to use either of the following instead:

  1. A single JLabel (centered in a scroll pane) to display whichever image the user is interested in at that moment. As seen in ImageViewer.
  2. A single row JList. As seen in this answer. The 'single row' part of that only works if they are all the same dimensions. Alternately, if you are prepared to scale the images on the fly, and they are all the same aspect ratio (e.g. 4:3 or 16:9).

The best way to remove duplicate values from NSMutableArray in Objective-C?

Here i removed duplicate name values from mainArray and store result in NSMutableArray(listOfUsers)

for (int i=0; i<mainArray.count; i++) {
    if (listOfUsers.count==0) {
        [listOfUsers addObject:[mainArray objectAtIndex:i]];

    }
   else if ([[listOfUsers valueForKey:@"name" ] containsObject:[[mainArray objectAtIndex:i] valueForKey:@"name"]])
    {  
       NSLog(@"Same object");
    }
    else
    {
        [listOfUsers addObject:[mainArray objectAtIndex:i]];
    }
}

Could not find method android() for arguments

You are using the wrong build.gradle file.

In your top-level file you can't define an android block.

Just move this part inside the module/build.gradle file.

android {
    compileSdkVersion 17
    buildToolsVersion '23.0.0'
}
dependencies {
    compile files('app/libs/junit-4.12-JavaDoc.jar')
}
apply plugin: 'maven'

Best Practice to Use HttpClient in Multithreaded Environment

Method A is recommended by httpclient developer community.

Please refer http://www.mail-archive.com/[email protected]/msg02455.html for more details.

How to downgrade Node version

Steps to downgrade to node8

brew install node@8
brew link node@8 --force

if warning remove the folder and files as indicated in the warning then again the command :

brew link node@8 --force

converting multiple columns from character to numeric format in r

I think I figured it out. Here's what I did (perhaps not the most elegant solution - suggestions on how to imp[rove this are very much welcome)

#names of columns in data frame
cols <- names(DF)
# character variables
cols.char <- c("fx_code","date")
#numeric variables
cols.num <- cols[!cols %in% cols.char]

DF.char <- DF[cols.char]
DF.num <- as.data.frame(lapply(DF[cols.num],as.numeric))
DF2 <- cbind(DF.char, DF.num)

How do I output an ISO 8601 formatted string in JavaScript?

There is already a function called toISOString():

var date = new Date();
date.toISOString(); //"2011-12-19T15:28:46.493Z"

If, somehow, you're on a browser that doesn't support it, I've got you covered:

if ( !Date.prototype.toISOString ) {
  ( function() {

    function pad(number) {
      var r = String(number);
      if ( r.length === 1 ) {
        r = '0' + r;
      }
      return r;
    }

    Date.prototype.toISOString = function() {
      return this.getUTCFullYear()
        + '-' + pad( this.getUTCMonth() + 1 )
        + '-' + pad( this.getUTCDate() )
        + 'T' + pad( this.getUTCHours() )
        + ':' + pad( this.getUTCMinutes() )
        + ':' + pad( this.getUTCSeconds() )
        + '.' + String( (this.getUTCMilliseconds()/1000).toFixed(3) ).slice( 2, 5 )
        + 'Z';
    };

  }() );
}

Multi-threading in VBA

I know the question specifies Excel, but since the same question for Access got marked as duplicate, so I will post my answer here. The principle is simple: open a new Access application, then open a form with a timer inside that application, send the function/sub you want to execute to that form, execute the task if the timer hits, and quit the application once execution has finished. This allows the VBA to work with tables and queries from your database. Note: it will throw errors if you've exclusively locked the database.

This is all VBA (as opposed to other answers)

The function that runs a sub/function asynchronously

Public Sub RunFunctionAsync(FunctionName As String)
    Dim A As Access.Application
    Set A = New Access.Application
    A.OpenCurrentDatabase Application.CurrentProject.FullName
    A.DoCmd.OpenForm "MultithreadingEngine"
    With A.Forms("MultiThreadingEngine")
        .TimerInterval = 10
        .AddToTaskCollection (FunctionName)
    End With
End Sub

The module of the form required to achieve this

(form name = MultiThreadingEngine, doesn't have any controls or properties set)

Public TaskCollection As Collection

Public Sub AddToTaskCollection(str As String)
    If TaskCollection Is Nothing Then
        Set TaskCollection = New Collection
    End If
    TaskCollection.Add str
End Sub
Private Sub Form_Timer()
    If Not TaskCollection Is Nothing Then
        If TaskCollection.Count <> 0 Then
            Dim CollectionItem As Variant
            For Each CollectionItem In TaskCollection
                Run CollectionItem
            Next CollectionItem
        End If
    End If
    Application.Quit
End Sub

Implementing support for parameters should be easy enough, returning values is difficult, however.

Detecting when user scrolls to bottom of div with jQuery

If you need to use this on a div that has overflow-y as hidden or scroll, something like this may be what you need.

if ($('#element').prop('scrollHeight') - $('#element').scrollTop() <= Math.ceil($('#element').height())) {
    at_bottom = true;
}

I found ceil was needed because prop scrollHeight seems to round, or perhaps some other reason causing this to be off by less than 1.

Using a custom (ttf) font in CSS

This is not a system font. this font is not supported in other systems. you can use font-face, convert font from this Site or from this

enter image description here

PHP Session timeout

<script type="text/javascript">
window.setTimeout("location=('timeout_session.htm');",900000);
</script>

In the header of every page has been working for me during site tests(the site is not yet in production). The HTML page it falls to ends the session and just informs the user of the need to log in again. This seems an easier way than playing with PHP logic. I'd love some comments on the idea. Any traps I havent seen in it ?

Check if the number is integer

Here is one, apparently reliable way:

check.integer <- function(N){
    !grepl("[^[:digit:]]", format(N,  digits = 20, scientific = FALSE))
}

check.integer(3243)
#TRUE
check.integer(3243.34)
#FALSE
check.integer("sdfds")
#FALSE

This solution also allows for integers in scientific notation:

> check.integer(222e3)
[1] TRUE

SQL Error: ORA-00922: missing or invalid option

there's nothing wrong with using CHAR like that.. I think your problem is that you have a space in your tablename. It should be: charteredflight or chartered_flight..

Making a cURL call in C#

I know this is a very old question but I post this solution in case it helps somebody. I recently met this problem and google led me here. The answer here helps me to understand the problem but there are still issues due to my parameter combination. What eventually solves my problem is curl to C# converter. It is a very powerful tool and supports most of the parameters for Curl. The code it generates is almost immediately runnable.

Installing a local module using npm?

From the npm-link documentation:

In the local module directory:

$ cd ./package-dir
$ npm link

In the directory of the project to use the module:

$ cd ./project-dir
$ npm link package-name

Or in one go using relative paths:

$ cd ./project-dir
$ npm link ../package-dir

This is equivalent to using two commands above under the hood.

Javascript onload not working

There's nothing wrong with include file in head. It seems you forgot to add;. Please try this one:

<body onload="imageRefreshBig();">

But as per my knowledge semicolons are optional. You can try with ; but better debug code and see if chrome console gives any error.

I hope this helps.

Performing user authentication in Java EE / JSF using j_security_check

After searching the Web and trying many different ways, here's what I'd suggest for Java EE 6 authentication:

Set up the security realm:

In my case, I had the users in the database. So I followed this blog post to create a JDBC Realm that could authenticate users based on username and MD5-hashed passwords in my database table:

http://blog.gamatam.com/2009/11/jdbc-realm-setup-with-glassfish-v3.html

Note: the post talks about a user and a group table in the database. I had a User class with a UserType enum attribute mapped via javax.persistence annotations to the database. I configured the realm with the same table for users and groups, using the userType column as the group column and it worked fine.

Use form authentication:

Still following the above blog post, configure your web.xml and sun-web.xml, but instead of using BASIC authentication, use FORM (actually, it doesn't matter which one you use, but I ended up using FORM). Use the standard HTML , not the JSF .

Then use BalusC's tip above on lazy initializing the user information from the database. He suggested doing it in a managed bean getting the principal from the faces context. I used, instead, a stateful session bean to store session information for each user, so I injected the session context:

 @Resource
 private SessionContext sessionContext;

With the principal, I can check the username and, using the EJB Entity Manager, get the User information from the database and store in my SessionInformation EJB.

Logout:

I also looked around for the best way to logout. The best one that I've found is using a Servlet:

 @WebServlet(name = "LogoutServlet", urlPatterns = {"/logout"})
 public class LogoutServlet extends HttpServlet {
  @Override
  protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   HttpSession session = request.getSession(false);

   // Destroys the session for this user.
   if (session != null)
        session.invalidate();

   // Redirects back to the initial page.
   response.sendRedirect(request.getContextPath());
  }
 }

Although my answer is really late considering the date of the question, I hope this helps other people that end up here from Google, just like I did.

Ciao,

Vítor Souza

How to replace all double quotes to single quotes using jquery?

You can also use replaceAll(search, replaceWith) [MDN].

Then, make sure you have a string by wrapping one type of quotes by a different type:

 'a "b" c'.replaceAll('"', "'")
 // result: "a 'b' c"
    
 'a "b" c'.replaceAll(`"`, `'`)
 // result: "a 'b' c"

 // Using RegEx. You MUST use a global RegEx(Meaning it'll match all occurrences).
 'a "b" c'.replaceAll(/\"/g, "'")
 // result: "a 'b' c"

Important(!) if you choose regex:

when using a regexp you have to set the global ("g") flag; otherwise, it will throw a TypeError: "replaceAll must be called with a global RegExp".

When is null or undefined used in JavaScript?

A property, when it has no definition, is undefined. null is an object. It's type is null. undefined is not an object, its type is undefined.

This is a good article explaining the difference and also giving some examples.

null vs undefined

Return index of highest value in an array

<?php

$array = array(11 => 14,
               10 => 9,
               12 => 7,
               13 => 7,
               14 => 4,
               15 => 6);

echo array_search(max($array), $array);

?>

array_search() return values:

Returns the key for needle if it is found in the array, FALSE otherwise.

If needle is found in haystack more than once, the first matching key is returned. To return the keys for all matching values, use array_keys() with the optional search_value parameter instead.

MySQL LEFT JOIN 3 tables

SELECT p.*, f.Fear
FROM Persons p
LEFT JOIN Person_Fear pf ON pf.PersonID = p.PersonID
LEFT JOIN Fears f ON f.FearID = pf.FearID
ORDER BY p.PersonID

  1. You need to select from the Persons table to ensure you generate a row for every person, whether they have fears or not.
  2. Then you can left join Person_Fear to every person, which will just be NULL if they don't have any entries (as you want).
  3. Finally, you left join Fears on Person_Fear so that you can select the name of the fear.
  4. Optionally, add an order so that each person has all their fears listed together, even if they were added to the Person_Fear table at different times.

TCPDF not render all CSS properties

I recently ran into the same problem having the TCPDF work with my CSS. Take a look at the code below. It worked for me after I changed the standard CSS to a format PHP would understand

Code Sample Below

$table = '<table width="100%" cellspacing="0" cellpadding="55%">
          <tr valign="bottom">
                <td class="header1" rowspan="2" align="center" valign="middle"
                      width="6%">Category</td>
                <td class="header1" rowspan="2" align="center" valign="middle"
                      width="26%">Project Description</td>
          </tr></table>';

Is there a way that I can check if a data attribute exists?

You can create an extremely simple jQuery-plugin to query an element for this:

$.fn.hasData = function(key) {
  return (typeof $(this).data(key) != 'undefined');
};

Then you can simply use $("#dataTable").hasData('timer')

Gotchas:

  • Will return false only if the value does not exist (is undefined); if it's set to false/null it hasData() will still return true.
  • It's different from the built-in $.hasData() which only checks if any data on the element is set.

How to join on multiple columns in Pyspark?

An alternative approach would be:

df1 = sqlContext.createDataFrame(
    [(1, "a", 2.0), (2, "b", 3.0), (3, "c", 3.0)],
    ("x1", "x2", "x3"))

df2 = sqlContext.createDataFrame(
    [(1, "f", -1.0), (2, "b", 0.0)], ("x1", "x2", "x4"))

df = df1.join(df2, ['x1','x2'])
df.show()

which outputs:

+---+---+---+---+
| x1| x2| x3| x4|
+---+---+---+---+
|  2|  b|3.0|0.0|
+---+---+---+---+

With the main advantage being that the columns on which the tables are joined are not duplicated in the output, reducing the risk of encountering errors such as org.apache.spark.sql.AnalysisException: Reference 'x1' is ambiguous, could be: x1#50L, x1#57L.


Whenever the columns in the two tables have different names, (let's say in the example above, df2 has the columns y1, y2 and y4), you could use the following syntax:

df = df1.join(df2.withColumnRenamed('y1','x1').withColumnRenamed('y2','x2'), ['x1','x2'])

cURL equivalent in Node.js?

Here is a standard lib (http) async / await solution.

const http = require("http");

const fetch = async (url) => {
  return new Promise((resolve, reject) => {
    http
      .get(url, (resp) => {
        let data = "";
        resp.on("data", (chunk) => {
          data += chunk;
        });
        resp.on("end", () => {
          resolve(data);
        });
      })
      .on("error", (err) => {
        reject(err);
      });
  });
};

Usage:

await fetch("http://example.com");

javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure

I am getting similar errors recently because recent JDKs (and browsers, and the Linux TLS stack, etc.) refuse to communicate with some servers in my customer's corporate network. The reason of this is that some servers in this network still have SHA-1 certificates.

Please see: https://www.entrust.com/understanding-sha-1-vulnerabilities-ssl-longer-secure/ https://blog.qualys.com/ssllabs/2014/09/09/sha1-deprecation-what-you-need-to-know

If this would be your current case (recent JDK vs deprecated certificate encription) then your best move is to update your network to the proper encription technology.

In case that you should provide a temporal solution for that, please see another answers to have an idea about how to make your JDK trust or distrust certain encription algorithms:

How to force java server to accept only tls 1.2 and reject tls 1.0 and tls 1.1 connections

Anyway I insist that, in case that I have guessed properly your problem, this is not a good solution to the problem and that your network admin should consider removing these deprecated certificates and get a new one.

Set variable with multiple values and use IN

Ideally you shouldn't be splitting strings in T-SQL at all.

Barring that change, on older versions before SQL Server 2016, create a split function:

CREATE FUNCTION dbo.SplitStrings
(
    @List      nvarchar(max), 
    @Delimiter nvarchar(2)
)
RETURNS TABLE
WITH SCHEMABINDING
AS
  RETURN ( WITH x(x) AS
    (
      SELECT CONVERT(xml, N'<root><i>' 
        + REPLACE(@List, @Delimiter, N'</i><i>') 
        + N'</i></root>')
    )
    SELECT Item = LTRIM(RTRIM(i.i.value(N'.',N'nvarchar(max)')))
      FROM x CROSS APPLY x.nodes(N'//root/i') AS i(i)
  );
GO

Now you can say:

DECLARE @Values varchar(1000);

SET @Values = 'A, B, C';

SELECT blah
  FROM dbo.foo
  INNER JOIN dbo.SplitStrings(@Values, ',') AS s
    ON s.Item = foo.myField;

On SQL Server 2016 or above (or Azure SQL Database), it is much simpler and more efficient, however you do have to manually apply LTRIM() to take away any leading spaces:

DECLARE @Values varchar(1000) = 'A, B, C';

SELECT blah
  FROM dbo.foo
  INNER JOIN STRING_SPLIT(@Values, ',') AS s
    ON LTRIM(s.value) = foo.myField;

Seeing if data is normally distributed in R

In addition to qqplots and the Shapiro-Wilk test, the following methods may be useful.

Qualitative:

  • histogram compared to the normal
  • cdf compared to the normal
  • ggdensity plot
  • ggqqplot

Quantitative:

The qualitive methods can be produced using the following in R:

library("ggpubr")
library("car")

h <- hist(data, breaks = 10, density = 10, col = "darkgray") 
xfit <- seq(min(data), max(data), length = 40) 
yfit <- dnorm(xfit, mean = mean(data), sd = sd(data)) 
yfit <- yfit * diff(h$mids[1:2]) * length(data) 
lines(xfit, yfit, col = "black", lwd = 2)

plot(ecdf(data), main="CDF")
lines(ecdf(rnorm(10000)),col="red")

ggdensity(data)

ggqqplot(data)

A word of caution - don't blindly apply tests. Having a solid understanding of stats will help you understand when to use which tests and the importance of assumptions in hypothesis testing.

Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

First, knowing where the data directory was for me was the key. /usr/local/var/mysql In here, there was at least one file with extension .err preceded with my local machine name. It had all info i needed to diagnose.

I think i screwed up by installing mysql 8 first. My app isn't compatible with it so i had to downgrade back to 5.7

My solution that worked for me was going to /usr/local/etc/my.cnf

Find this line if its there. I think its mysql 8 related:

mysqlx-bind-address = 127.0.0.1 

Remove it because in the mysql 5.7 says it doesnt like it in the error log

Also add this line in there if its not there under the bind-address.

socket=/tmp/mysql.sock

Go to the /tmp directory and delete any mysql.sock files in there. On server start, it will recreate the sock files

Trash out the data directory with mySQL in the stopped state. Mine was /usr/local/var/mysql . This is the same place where the logs are at

From there i ran

>mysqld --initialize

Then everything started working...this command will give you a random password at the end. Save that password for the next step

Running this to assign my own password.

>mysql_secure_installation 

Both

>brew services stop [email protected]

and

>mysql.server start

are now working. Hope this helps. It's about 3 hours of trial and error.

Calling the base constructor in C#

From Framework Design Guidelines and FxCop rules.:

1. Custom Exception should have a name that ends with Exception

    class MyException : Exception

2. Exception should be public

    public class MyException : Exception

3. CA1032: Exception should implements standard constructors.

  • A public parameterless constructor.
  • A public constructor with one string argument.
  • A public constructor with one string and Exception (as it can wrap another Exception).
  • A serialization constructor protected if the type is not sealed and private if the type is sealed. Based on MSDN:

    [Serializable()]
    public class MyException : Exception
    {
      public MyException()
      {
         // Add any type-specific logic, and supply the default message.
      }
    
      public MyException(string message): base(message) 
      {
         // Add any type-specific logic.
      }
      public MyException(string message, Exception innerException): 
         base (message, innerException)
      {
         // Add any type-specific logic for inner exceptions.
      }
      protected MyException(SerializationInfo info, 
         StreamingContext context) : base(info, context)
      {
         // Implement type-specific serialization constructor logic.
      }
    }  
    

or

    [Serializable()]
    public sealed class MyException : Exception
    {
      public MyException()
      {
         // Add any type-specific logic, and supply the default message.
      }

      public MyException(string message): base(message) 
      {
         // Add any type-specific logic.
      }
      public MyException(string message, Exception innerException): 
         base (message, innerException)
      {
         // Add any type-specific logic for inner exceptions.
      }
      private MyException(SerializationInfo info, 
         StreamingContext context) : base(info, context)
      {
         // Implement type-specific serialization constructor logic.
      }
    }  

What is the "realm" in basic authentication

According to the RFC 7235, the realm parameter is reserved for defining protection spaces (set of pages or resources where credentials are required) and it's used by the authentication schemes to indicate a scope of protection.

For more details, see the quote below (the highlights are not present in the RFC):

2.2. Protection Space (Realm)

The "realm" authentication parameter is reserved for use by authentication schemes that wish to indicate a scope of protection.

A protection space is defined by the canonical root URI (the scheme and authority components of the effective request URI) of the server being accessed, in combination with the realm value if present. These realms allow the protected resources on a server to be partitioned into a set of protection spaces, each with its own authentication scheme and/or authorization database. The realm value is a string, generally assigned by the origin server, that can have additional semantics specific to the authentication scheme. Note that a response can have multiple challenges with the same auth-scheme but with different realms. [...]


Note 1: The framework for HTTP authentication is currently defined by the RFC 7235, which updates the RFC 2617 and makes the RFC 2616 obsolete.

Note 2: The realm parameter is no longer always required on challenges.

How to complete the RUNAS command in one line

The runas command does not allow a password on its command line. This is by design (and also the reason you cannot pipe a password to it as input). Raymond Chen says it nicely:

The RunAs program demands that you type the password manually. Why doesn't it accept a password on the command line?

This was a conscious decision. If it were possible to pass the password on the command line, people would start embedding passwords into batch files and logon scripts, which is laughably insecure.

In other words, the feature is missing to remove the temptation to use the feature insecurely.

Which data type for latitude and longitude?

In PostGIS Geometry is preferred over Geography (round earth model) because the computations are much simpler therefore faster. It also has MANY more available functions but is less accurate over very long distances.

Import your CSV long and lat fields to DECIMAL(10,6) columns. 6 digits is 10cm precision, should be plenty for most use cases. Then cast your imported data to the correct SRID

The wrong way!

/* try what seems the obvious solution */
DROP TABLE IF EXISTS public.test_geom_bad;
-- Big Ben, London
SELECT ST_SetSRID(ST_MakePoint(-0.116773, 51.510357),4326) AS geom
INTO public.test_geom_bad;

The CORRECT way

/* add the necessary CAST to make it work */
DROP TABLE IF EXISTS public.test_geom_correct;
SELECT ST_SetSRID(ST_MakePoint(-0.116773, 51.510357),4326)::geometry(Geometry, 4326) AS geom
INTO public.test_geom_correct;

Verify SRID is not zero!

/* now observe the incorrect SRID 0 */
SELECT * FROM public.geometry_columns
WHERE f_table_name IN ('test_geom_bad','test_geom_correct');

Validate the order of your long lat parameter using a WKT viewer and

SELECT ST_AsEWKT(geom) FROM public.test_geom_correct

Then index it for best performance

CREATE INDEX idx_target_table_geom_gist
    ON target_table USING gist(geom);

Python 2.7: %d, %s, and float()

See String Formatting Operations:

%d is the format code for an integer. %f is the format code for a float.

%s prints the str() of an object (What you see when you print(object)).

%r prints the repr() of an object (What you see when you print(repr(object)).

For a float %s, %r and %f all display the same value, but that isn't the case for all objects. The other fields of a format specifier work differently as well:

>>> print('%10.2s' % 1.123) # print as string, truncate to 2 characters in a 10-place field.
        1.
>>> print('%10.2f' % 1.123) # print as float, round to 2 decimal places in a 10-place field.
      1.12

Convenient C++ struct initialisation

Many compilers' C++ frontends (including GCC and clang) understand C initializer syntax. If you can, simply use that method.

Showing line numbers in IPython/Jupyter Notebooks

You can also find Toggle Line Numbers under View on the top toolbar of the Jupyter notebook in your browser. This adds/removes the lines numbers in all notebook cells.

For me, Esc+l only added/removed the line numbers of the active cell.

Traits vs. interfaces

The trait is same as a class we can use for multiple inheritance purposes and also code reusability.

We can use trait inside the class and also we can use multiple traits in the same class with 'use keyword'.

The interface is using for code reusability same as a trait

the interface is extend multiple interfaces so we can solve the multiple inheritance problems but when we implement the interface then we should create all the methods inside the class. For more info click below link:

http://php.net/manual/en/language.oop5.traits.php http://php.net/manual/en/language.oop5.interfaces.php

How to insert tab character when expandtab option is on in Vim

You can disable expandtab option from within Vim as below:

:set expandtab!

or

:set noet

PS: And set it back when you are done with inserting tab, with "set expandtab" or "set et"

PS: If you have tab set equivalent to 4 spaces in .vimrc (softtabstop), you may also like to set it to 8 spaces in order to be able to insert a tab by pressing tab key once instead of twice (set softtabstop=8).

Invalid length for a Base-64 char array

The length of a base64 encoded string is always a multiple of 4. If it is not a multiple of 4, then = characters are appended until it is. A query string of the form ?name=value has problems when the value contains = charaters (some of them will be dropped, I don't recall the exact behavior). You may be able to get away with appending the right number of = characters before doing the base64 decode.

Edit 1

You may find that the value of UserNameToVerify has had "+"'s changed to " "'s so you may need to do something like so:

a = a.Replace(" ", "+");

This should get the length right;

int mod4 = a.Length % 4;
if (mod4 > 0 )
{
    a += new string('=', 4 - mod4);
}

Of course calling UrlEncode (as in LukeH's answer) should make this all moot.

how to cancel/abort ajax request in axios

Using cp-axios wrapper you able to abort your requests with three diffent types of the cancellation API:

1. Promise cancallation API (CPromise):

Live browser example

 const cpAxios= require('cp-axios');
 const url= 'https://run.mocky.io/v3/753aa609-65ae-4109-8f83-9cfe365290f0?mocky-delay=5s';
 
 const chain = cpAxios(url)
      .timeout(5000)
      .then(response=> {
          console.log(`Done: ${JSON.stringify(response.data)}`)
      }, err => {
          console.warn(`Request failed: ${err}`)
      });
 
 setTimeout(() => {
    chain.cancel();
 }, 500);

2. Using AbortController signal API:

 const cpAxios= require('cp-axios');
 const CPromise= require('c-promise2');
 const url= 'https://run.mocky.io/v3/753aa609-65ae-4109-8f83-9cfe365290f0?mocky-delay=5s';
 
 const abortController = new CPromise.AbortController();
 const {signal} = abortController;
 
 const chain = cpAxios(url, {signal})
      .timeout(5000)
      .then(response=> {
          console.log(`Done: ${JSON.stringify(response.data)}`)
      }, err => {
          console.warn(`Request failed: ${err}`)
      });
 
 setTimeout(() => {
    abortController.abort();
 }, 500);

3. Using a plain axios cancelToken:

 const cpAxios= require('cp-axios');
 const url= 'https://run.mocky.io/v3/753aa609-65ae-4109-8f83-9cfe365290f0?mocky-delay=5s';

 const source = cpAxios.CancelToken.source();
 
 cpAxios(url, {cancelToken: source.token})
      .timeout(5000)
      .then(response=> {
          console.log(`Done: ${JSON.stringify(response.data)}`)
      }, err => {
          console.warn(`Request failed: ${err}`)
      });
 
 setTimeout(() => {
    source.cancel();
 }, 500);

How to preSelect an html dropdown list with php?

This is the solution that I've came up with:

<form name = "form1" id = "form1" action = "#" method = "post">
  <select name = "DropDownList1" id = "DropDownList1">
<?php
$arr = array('Yes', 'No', 'Fine' ); // create array so looping is easier
for( $i = 1; $i <= 3; $i++ ) // loop starts at first value and ends at last value
{
  $selected = ''; // keep selected at nothing
  if( isset( $_POST['go'] ) ) // check if form was submitted
  {
    if( $_POST['DropDownList1'] == $i ) // if the value of the dropdownlist is equal to the looped variable
    {
      $selected = 'selected = "selected"'; // if is equal, set selected = "selected"
    }
  }
  // note: if value is not equal, selected stays defaulted to nothing as explained earlier
  echo '<option value = "' . $i . '"' . $selected . '>' . $arr[$i] . '</option>'; // echo the option element to the page using the $selected variable
}
?>
  </select> <!-- finish the form in html -->
  <input type="text" value="" name="name">
  <input type="submit" value="go" name="go">
</form>

The code I have works as long as the values are integers in some numeric order ( ascending or descending ). What it does is starts the dropdownlist in html, and adds each option element in php code. It will not work if you have random values though, i.e: 1, 4, 2, 7, 6. Each value must be unique.

What is the point of the diamond operator (<>) in Java 7?

In theory, the diamond operator allows you to write more compact (and readable) code by saving repeated type arguments. In practice, it's just two confusing chars more giving you nothing. Why?

  1. No sane programmer uses raw types in new code. So the compiler could simply assume that by writing no type arguments you want it to infer them.
  2. The diamond operator provides no type information, it just says the compiler, "it'll be fine". So by omitting it you can do no harm. At any place where the diamond operator is legal it could be "inferred" by the compiler.

IMHO, having a clear and simple way to mark a source as Java 7 would be more useful than inventing such strange things. In so marked code raw types could be forbidden without losing anything.

Btw., I don't think that it should be done using a compile switch. The Java version of a program file is an attribute of the file, no option at all. Using something as trivial as

package 7 com.example;

could make it clear (you may prefer something more sophisticated including one or more fancy keywords). It would even allow to compile sources written for different Java versions together without any problems. It would allow introducing new keywords (e.g., "module") or dropping some obsolete features (multiple non-public non-nested classes in a single file or whatsoever) without losing any compatibility.

wp_nav_menu change sub-menu class name?

This may be useful to you

How to add a parent class for menu item

function wpdocs_add_menu_parent_class( $items ) {
$parents = array();

// Collect menu items with parents.
foreach ( $items as $item ) {
    if ( $item->menu_item_parent && $item->menu_item_parent > 0 ) {
        $parents[] = $item->menu_item_parent;
    }
}

// Add class.
foreach ( $items as $item ) {
    if ( in_array( $item->ID, $parents ) ) {
        $item->classes[] = 'menu-parent-item';
    }
}
return $items;
 }
add_filter( 'wp_nav_menu_objects', 'wpdocs_add_menu_parent_class' );

/**
 * Add a parent CSS class for nav menu items.
 * @param array  $items The menu items, sorted by each menu item's menu order.
 * @return array (maybe) modified parent CSS class.
*/

Adding Conditional Classes to Menu Items

function wpdocs_special_nav_class( $classes, $item ) {
    if ( is_single() && 'Blog' == $item->title ) {
    // Notice you can change the conditional from is_single() and $item->title
    $classes[] = "special-class";
}
return $classes;
}
add_filter( 'nav_menu_css_class' , 'wpdocs_special_nav_class' , 10, 2 );

For reference : click me

Fit image to table cell [Pure HTML]

Use your developer's tool of choice and check if the tr, td or img has any padding or margins.

Pass in an enum as a method parameter

If you want to pass in the value to use, you have to use the enum type you declared and directly use the supplied value:

public string CreateFile(string id, string name, string description,
              /* --> */  SupportedPermissions supportedPermissions)
{
    file = new File
    {  
        Name = name,
        Id = id,
        Description = description,
        SupportedPermissions = supportedPermissions // <---
    };

    return file.Id;
}

If you instead want to use a fixed value, you don't need any parameter at all. Instead, directly use the enum value. The syntax is similar to a static member of a class:

public string CreateFile(string id, string name, string description) // <---
{
    file = new File
    {  
        Name = name,
        Id = id,
        Description = description,
        SupportedPermissions = SupportedPermissions.basic // <---
    };

    return file.Id;
}

How can I import Swift code to Objective-C?

Find the .PCH file inside the project. and then add #import "YourProjectName-Swift.h" This will import the class headers. So that you don't have to import into specific file.

#ifndef __IPHONE_3_0
#warning "This project uses features only available in iPhone SDK 3.0 and later."
#endif


#ifdef __OBJC__
    #import <Foundation/Foundation.h>
    #import <UIKit/UIKit.h>
    #import "YourProjectName-Swift.h"
#endif

Splitting a Java String by the pipe symbol using split("|")

Use proper escaping: string.split("\\|")

Or, in Java 5+, use the helper Pattern.quote() which has been created for exactly this purpose:

string.split(Pattern.quote("|"))

which works with arbitrary input strings. Very useful when you need to quote / escape user input.

GridView Hide Column by code

What most answers here don't explain is - what if you need to make columns visible again and invisible, all based on data dynamically? After all, shouldn't GridViews be data centric?

What if you want to turn ON or OFF columns based on your data?

My Gridview

<asp:GridView ID="gvLocationBoard" runat="server" AllowPaging="True" AllowSorting="True" ShowFooter="false" ShowHeader="true" Visible="true" AutoGenerateColumns="false" CellPadding="4" ForeColor="#333333" GridLines="None"
            DataSourceID="sdsLocationBoard" OnDataBound="gvLocationBoard_DataBound" OnRowDataBound="gvLocationBoard_RowDataBound" PageSize="15" OnPreRender="gvLocationBoard_PreRender">
            <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
            <Columns>
                <asp:TemplateField HeaderText="StudentID" SortExpression="StudentID" Visible="False">
                    <ItemTemplate>
                        <asp:Label ID="Label2" runat="server" Text='<%# Eval("StudentID") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Student" SortExpression="StudentName">
                    <ItemTemplate>
                        <asp:Label ID="Label3" runat="server" Text='<%# Eval("StudentName") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Status" SortExpression="CheckStatusName" ItemStyle-HorizontalAlign="Center">
                    <ItemTemplate>
                        <asp:HiddenField ID="hfStatusID" runat="server" Value='<%# Eval("CheckStatusID") %>' />
                        <asp:Label ID="Label4" runat="server" Text='<%# Eval("CheckStatusName") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="RollCallPeriod0" Visible="False">
                    <ItemTemplate>
                        <asp:CheckBox ID="cbRollCallPeriod0" runat="server" />
                        <asp:HiddenField ID="hfRollCallPeriod0" runat="server" Value='<%# Eval("RollCallPeriod") %>' />
                    </ItemTemplate>
                    <HeaderStyle Font-Size="Small" />
                    <ItemStyle HorizontalAlign="Center" />
                </asp:TemplateField>
                <asp:TemplateField HeaderText="RollCallPeriod1" Visible="False">
                    <ItemTemplate>
                        <asp:CheckBox ID="cbRollCallPeriod1" runat="server" />
                        <asp:HiddenField ID="hfRollCallPeriod1" runat="server" Value='<%# Eval("RollCallPeriod") %>' />
                    </ItemTemplate>
                    <HeaderStyle Font-Size="Small" />
                    <ItemStyle HorizontalAlign="Center" />
                </asp:TemplateField>
        ..
etc..

Note the `"RollCallPeriodn", where 'n' is a sequential number.

The way I do it, is to by design hide all columns that I know are going to be ON (visible="true") or OFF (visible="false") later, and depending on my data.

In my case I want to display Period Times up to a certain column. So for example, if today is 9am then I want to show periods 6am, 7am, 8am and 9am, but not 10am, 11am, etc.

On other days I want to show ALL the times. And so on.

So how do we do this?

Why not use PreRender to "reset" the Gridview?

protected void gvLocationBoard_PreRender(object sender, EventArgs e)
{
    GridView gv = (GridView)sender;
    int wsPos = 3;
    for (int wsCol = 0; wsCol < 19; wsCol++)
    {
        gv.Columns[wsCol + wsPos].HeaderText = "RollCallPeriod" + wsCol.ToString("{0,00}");
        gv.Columns[wsCol + wsPos].Visible = false;
    }
}

Now turn ON the columns you need based on finding the Start of the HeaderText and make the column visible if the header text is not the default.

  protected void gvLocationBoard_DataBound(object sender, EventArgs e)
    {
        //Show the headers for the Period Times directly from sdsRollCallPeriods
        DataSourceSelectArguments dss = new DataSourceSelectArguments();
        DataView dv = sdsRollCallPeriods.Select(dss) as DataView;
        DataTable dt = dv.ToTable() as DataTable;
        if (dt != null)
        {
            int wsPos = 0;
            int wsCol = 3;  //start of PeriodTimes column in gvLocationBoard
            foreach (DataRow dr in dt.Rows)
            {
                gvLocationBoard.Columns[wsCol + wsPos].HeaderText = dr.ItemArray[1].ToString();
                gvLocationBoard.Columns[wsCol + wsPos].Visible = !gvLocationBoard.Columns[wsCol + wsPos].HeaderText.StartsWith("RollCallPeriod");

                wsPos += 1;
            }
        }
    }

I won't reveal the SqlDataSource here, but suffice to say with the PreRender, I can reset my GridView and turn ON the columns I want with the headers I want.

So the way it works is that everytime you select a different date or time periods to display as headers, it resets the GridView to the default header text and Visible="false" status before it builds the gridview again. Otherwise, without the PreRender, the GridView will have the previous data's headers as the code behind wipes the default settings.

How to get the changes on a branch in Git

This is similar to the answer I posted on: Preview a Git push

Drop these functions into your Bash profile:

  • gbout - git branch outgoing
  • gbin - git branch incoming

You can use this like:

  • If on master: gbin branch1 <-- this will show you what's in branch1 and not in master
  • If on master: gbout branch1 <-- this will show you what's in master that's not in branch 1

This will work with any branch.

function parse_git_branch {
  git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/\1/'
}

function gbin {
    echo branch \($1\) has these commits and \($(parse_git_branch)\) does not
    git log ..$1 --no-merges --format='%h | Author:%an | Date:%ad | %s' --date=local
}

function gbout {
    echo branch \($(parse_git_branch)\) has these commits and \($1\) does not
    git log $1.. --no-merges --format='%h | Author:%an | Date:%ad | %s' --date=local
}

Chrome Fullscreen API

Here are some functions I created for working with fullscreen in the browser.

They provide both enter/exit fullscreen across most major browsers.

function isFullScreen()
{
    return (document.fullScreenElement && document.fullScreenElement !== null)
         || document.mozFullScreen
         || document.webkitIsFullScreen;
}


function requestFullScreen(element)
{
    if (element.requestFullscreen)
        element.requestFullscreen();
    else if (element.msRequestFullscreen)
        element.msRequestFullscreen();
    else if (element.mozRequestFullScreen)
        element.mozRequestFullScreen();
    else if (element.webkitRequestFullscreen)
        element.webkitRequestFullscreen();
}

function exitFullScreen()
{
    if (document.exitFullscreen)
        document.exitFullscreen();
    else if (document.msExitFullscreen)
        document.msExitFullscreen();
    else if (document.mozCancelFullScreen)
        document.mozCancelFullScreen();
    else if (document.webkitExitFullscreen)
        document.webkitExitFullscreen();
}

function toggleFullScreen(element)
{
    if (isFullScreen())
        exitFullScreen();
    else
        requestFullScreen(element || document.documentElement);
}

Sort Java Collection

You can also use:

Collections.sort(list, new Comparator<CustomObject>() {
    public int compare(CustomObject obj1, CustomObject obj2) {
        return obj1.id - obj2.id;
    }
});
System.out.println(list);

Java File - Open A File And Write To It

Suggestions:

  • Create a File object that refers to the already existing file on disk.
  • Use a FileWriter object, and use the constructor that takes the File object and a boolean, the latter if true would allow appending text into the File if it exists.
  • Then initialize a PrintWriter passing in the FileWriter into its constructor.
  • Then call println(...) on your PrintWriter, writing your new text into the file.
  • As always, close your resources (the PrintWriter) when you are done with it.
  • As always, don't ignore exceptions but rather catch and handle them.
  • The close() of the PrintWriter should be in the try's finally block.

e.g.,

  PrintWriter pw = null;

  try {
     File file = new File("fubars.txt");
     FileWriter fw = new FileWriter(file, true);
     pw = new PrintWriter(fw);
     pw.println("Fubars rule!");
  } catch (IOException e) {
     e.printStackTrace();
  } finally {
     if (pw != null) {
        pw.close();
     }
  }

Easy, no?

How could I create a function with a completion handler in Swift?

We can use Closures for this purpose. Try the following

func loadHealthCareList(completionClosure: (indexes: NSMutableArray)-> ()) {
      //some code here
      completionClosure(indexes: list)
}

At some point we can call this function as given below.

healthIndexManager.loadHealthCareList { (indexes) -> () in
            print(indexes)
}

Please refer the following link for more information regarding Closures.

https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Closures.html

Is a slash ("/") equivalent to an encoded slash ("%2F") in the path portion of an HTTP URL

The story of %2F vs / was that, according to the initial W3C recommendations, slashes «must imply a hierarchical structure»:

The slash ("/", ASCII 2F hex) character is reserved for the delimiting of substrings whose relationship is hierarchical. This enables partial forms of the URI.

Example 2

The URIs

http://www.w3.org/albert/bertram/marie-claude

and

http://www.w3.org/albert/bertram%2Fmarie-claude

are NOT identical, as in the second case the encoded slash does not have hierarchical significance.

Provisioning Profiles menu item missing from Xcode 5

Try this:

Xcode >> Preferences >> Accounts

How to correctly set the ORACLE_HOME variable on Ubuntu 9.x?

This is the right way to clear this error.

export ORACLE_HOME=/u01/app/oracle/product/10.2.0/db_1 sqlplus / as sysdba

How to convert a string Date to long millseconds

using simpledateformat you can easily achieve it.

1) First convert string to java.Date using simpledateformatter.

2) Use getTime method to obtain count of millisecs from date

 public class test {
      public static void main(String[] args) {
      String currentDate = "01-March-2016";
      SimpleDateFormat f = new SimpleDateFormat("dd-MMM-yyyy");
     Date parseDate = f.parse(currentDate);
     long milliseconds = parseDate.getTime();
  }
        }

more Example click here

How to increase Maximum Upload size in cPanel?

In my case it was wp-admin/.user.ini:

post_max_size = 33M
upload_max_filesize = 32M

Rename a column in MySQL

for mysql version 5

alter table *table_name* change column *old_column_name* *new_column_name* datatype();

NSOperation vs Grand Central Dispatch

Another reason to prefer NSOperation over GCD is the cancelation mechanism of NSOperation. For example, an App like 500px that shows dozens of photos, use NSOperation we can cancel requests of invisible image cells when we scroll table view or collection view, this can greatly improve App performance and reduce memory footprint. GCD can't easily support this.

Also with NSOperation, KVO can be possible.

Here is an article from Eschaton which is worth reading.

Sending string via socket (python)

import socket
from threading import *

serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = "192.168.1.3"
port = 8000
print (host)
print (port)
serversocket.bind((host, port))

class client(Thread):
    def __init__(self, socket, address):
        Thread.__init__(self)
        self.sock = socket
        self.addr = address
        self.start()

    def run(self):
        while 1:
            print('Client sent:', self.sock.recv(1024).decode())
            self.sock.send(b'Oi you sent something to me')

serversocket.listen(5)
print ('server started and listening')
while 1:
    clientsocket, address = serversocket.accept()
    client(clientsocket, address)

This is a very VERY simple design for how you could solve it. First of all, you need to either accept the client (server side) before going into your while 1 loop because in every loop you accept a new client, or you do as i describe, you toss the client into a separate thread which you handle on his own from now on.

Action bar navigation modes are deprecated in Android L

For 'replacement' of deprecated ActionBar, I changed the type of my ActionBar-type variables to PagerTabStrip, as per (old code in comment):

// ActionBar bigActionBar;
PagerTabStrip bigActionBar;

A 'replacement' for ~actionBar's .selectTab(tabindex) was to use my associated ViewPager's .setCurrentItem(int) method, like this (old code in comment):

/*
ActionBar.Tab eventTab = bigActionBar.getTabAt(2);
bigActionBar.selectTab(eventTab);
*/
mViewPager.setCurrentItem(2);

Hope this is helpful.

How to download a file via FTP with Python ftplib

A = filename

ftp = ftplib.FTP("IP")
ftp.login("USR Name", "Pass")
ftp.cwd("/Dir")


try:
    ftp.retrbinary("RETR " + filename ,open(A, 'wb').write)
except:
    print "Error"

How to download a file over HTTP?

Python 3

  • urllib.request.urlopen

    import urllib.request
    response = urllib.request.urlopen('http://www.example.com/')
    html = response.read()
    
  • urllib.request.urlretrieve

    import urllib.request
    urllib.request.urlretrieve('http://www.example.com/songs/mp3.mp3', 'mp3.mp3')
    

    Note: According to the documentation, urllib.request.urlretrieve is a "legacy interface" and "might become deprecated in the future" (thanks gerrit)

Python 2

  • urllib2.urlopen (thanks Corey)

    import urllib2
    response = urllib2.urlopen('http://www.example.com/')
    html = response.read()
    
  • urllib.urlretrieve (thanks PabloG)

    import urllib
    urllib.urlretrieve('http://www.example.com/songs/mp3.mp3', 'mp3.mp3')
    

How do I get a class instance of generic type T?

I was looking for a way to do this myself without adding an extra dependency to the classpath. After some investigation I found that it is possible as long as you have a generic supertype. This was OK for me as I was working with a DAO layer with a generic layer supertype. If this fits your scenario then it's the neatest approach IMHO.

Most generics use cases I've come across have some kind of generic supertype e.g. List<T> for ArrayList<T> or GenericDAO<T> for DAO<T>, etc.

Pure Java solution

The article Accessing generic types at runtime in Java explains how you can do it using pure Java.

@SuppressWarnings("unchecked")
public GenericJpaDao() {
  this.entityBeanType = ((Class) ((ParameterizedType) getClass()
      .getGenericSuperclass()).getActualTypeArguments()[0]);
}

Spring solution

My project was using Spring which is even better as Spring has a handy utility method for finding the type. This is the best approach for me as it looks neatest. I guess if you weren't using Spring you could write your own utility method.

import org.springframework.core.GenericTypeResolver;

public abstract class AbstractHibernateDao<T extends DomainObject> implements DataAccessObject<T>
{

    @Autowired
    private SessionFactory sessionFactory;

    private final Class<T> genericType;

    private final String RECORD_COUNT_HQL;
    private final String FIND_ALL_HQL;

    @SuppressWarnings("unchecked")
    public AbstractHibernateDao()
    {
        this.genericType = (Class<T>) GenericTypeResolver.resolveTypeArgument(getClass(), AbstractHibernateDao.class);
        this.RECORD_COUNT_HQL = "select count(*) from " + this.genericType.getName();
        this.FIND_ALL_HQL = "from " + this.genericType.getName() + " t ";
    }

Why can't I find SQL Server Management Studio after installation?

It appears that SQL Server 2008 R2 can be downloaded with or without the management tools. I honestly have NO IDEA why someone would not want the management tools. But either way, the options are here:

http://www.microsoft.com/sqlserver/en/us/editions/express.aspx

and the one for 64 bit WITH the management tools (management studio) is here:

http://www.microsoft.com/sqlserver/en/us/editions/express.aspx

From the first link I presented, the 3rd and 4th include the management studio for 32 and 64 bit respectively.

PHP check if url parameter exists

I know this is an old question, but since php7.0 you can use the null coalescing operator (another resource).

It similar to the ternary operator, but will behave like isset on the lefthand operand instead of just using its boolean value.

$slide = $_GET["id"] ?? 'fallback';

So if $_GET["id"] is set, it returns the value. If not, it returns the fallback. I found this very helpful for $_POST, $_GET, or any passed parameters, etc

$slide = $_GET["id"] ?? '';

if (trim($slide) == 'link1') ...

What does "The APR based Apache Tomcat Native library was not found" mean?

I had this issue upgrading from Java 8 to 11. After adding this dependency, my app launched without issue:

<dependency>
    <groupId>org.javassist</groupId>
    <artifactId>javassist</artifactId>
    <version>3.25.0-GA</version>
</dependency>

How do I create a GUI for a windows application using C++?

Qt from Nokia is definitely the way to go. Another option is gtk, but Qt is better supported and documented. Either way, they are both free. And both of them are widely used and well known so it is easy to find answers to your questions.

Return multiple values from a SQL Server function

Example of using a stored procedure with multiple out parameters

As User Mr. Brownstone suggested you can use a stored procedure; to make it easy for all i created a minimalist example. First create a stored procedure:

Create PROCEDURE MultipleOutParameter
    @Input int,
    @Out1 int OUTPUT, 
    @Out2 int OUTPUT 
AS
BEGIN
    Select @Out1 = @Input + 1
    Select @Out2 = @Input + 2   
    Select 'this returns your normal Select-Statement' as Foo
          , 'amazing is it not?' as Bar

    -- Return can be used to get even more (afaik only int) values 
    Return(@Out1+@Out2+@Input)
END 

Calling the stored procedure

To execute the stored procedure a few local variables are needed to receive the value:

DECLARE @GetReturnResult int, @GetOut1 int, @GetOut2 int 
EXEC @GetReturnResult = MultipleOutParameter  
    @Input = 1,
    @Out1 = @GetOut1 OUTPUT,
    @Out2 = @GetOut2 OUTPUT

To see the values content you can do the following

Select @GetReturnResult as ReturnResult, @GetOut1 as Out_1, @GetOut2 as Out_2 

This will be the result:

Result of Stored Procedure Call with multiple out parameters

How do I remove blank elements from an array?

You can Try this

 cities.reject!(&:empty?)

Java : How to determine the correct charset encoding of a stream

You can certainly validate the file for a particular charset by decoding it with a CharsetDecoder and watching out for "malformed-input" or "unmappable-character" errors. Of course, this only tells you if a charset is wrong; it doesn't tell you if it is correct. For that, you need a basis of comparison to evaluate the decoded results, e.g. do you know beforehand if the characters are restricted to some subset, or whether the text adheres to some strict format? The bottom line is that charset detection is guesswork without any guarantees.

Working with UTF-8 encoding in Python source

In the source header you can declare:

#!/usr/bin/env python
# -*- coding: utf-8 -*-
....

It is described in the PEP 0263:

Then you can use UTF-8 in strings:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

u = 'idzie waz waska drózka'
uu = u.decode('utf8')
s = uu.encode('cp1250')
print(s)

This declaration is not needed in Python 3 as UTF-8 is the default source encoding (see PEP 3120).

In addition, it may be worth verifying that your text editor properly encodes your code in UTF-8. Otherwise, you may have invisible characters that are not interpreted as UTF-8.

Html.DropdownListFor selected value not being set

You should forget the class

SelectList

Use this in your Controller:

var customerTypes = new[] 
{ 
    new SelectListItem(){Value = "all", Text= "All"},
    new SelectListItem(){Value = "business", Text= "Business"},
    new SelectListItem(){Value = "private", Text= "Private"},
};

Select the value:

var selectedCustomerType = customerTypes.FirstOrDefault(d => d.Value == "private");
if (selectedCustomerType != null)
    selectedCustomerType.Selected = true;

Add the list to the ViewData:

ViewBag.CustomerTypes = customerTypes;

Use this in your View:

@Html.DropDownList("SectionType", (SelectListItem[])ViewBag.CustomerTypes)

-

More information at: http://www.asp.net/mvc/overview/older-versions/working-with-the-dropdownlist-box-and-jquery/using-the-dropdownlist-helper-with-aspnet-mvc

MySQL DELETE FROM with subquery as condition

I approached this in a slightly different way and it worked for me;

I needed to remove secure_links from my table that referenced the conditions table where there were no longer any condition rows left. A housekeeping script basically. This gave me the error - You cannot specify target table for delete.

So looking here for inspiration I came up with the below query and it works just fine. This is because it creates a temporary table sl1 that is used as the reference for the DELETE.

DELETE FROM `secure_links` WHERE `secure_links`.`link_id` IN 
            (
            SELECT
                `sl1`.`link_id` 
            FROM 
                (
                SELECT 

                    `sl2`.`link_id` 

                FROM 
                    `secure_links` AS `sl2` 
                    LEFT JOIN `conditions` ON `conditions`.`job` = `sl2`.`job` 

                WHERE 

                    `sl2`.`action` = 'something' AND 
                    `conditions`.`ref` IS NULL 
                ) AS `sl1`
            )

Works for me.

bootstrap multiselect get selected values

In your Html page please add

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Test the multiselect with ajax</title>

    <!-- Bootstrap -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.4.0/css/font-awesome.min.css">
    <!-- Bootstrap multiselect -->
    <link rel="stylesheet" href="http://davidstutz.github.io/bootstrap-multiselect/dist/css/bootstrap-multiselect.css">

    <!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
    <!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
    <!--[if lt IE 9]>
      <script src="https://oss.maxcdn.com/libs/html5shiv/3.7.2/html5shiv.js"></script>
      <script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
    <![endif]-->
  </head>
  <body>
    <div class="container">
      <br>

      <form method="post" id="myForm">

        <!-- Build your select: -->
        <select name="categories[]" id="example-getting-started" multiple="multiple" class="col-md-12">
          <option value="A">Cheese</option>
          <option value="B">Tomatoes</option>
          <option value="C">Mozzarella</option>
          <option value="D">Mushrooms</option>
          <option value="E">Pepperoni</option>
          <option value="F">Onions</option>
          <option value="G">10</option>
          <option value="H">11</option>
          <option value="I">12</option>
        </select>
        <br><br>
        <button type="button" class="btnSubmit"> Send </button>

      </form>

      <br><br>
      <div id="result">result</div>
    </div><!--container-->

    <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
    <!-- Include all compiled plugins (below), or include individual files as needed -->
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
    <!-- Bootstrap multiselect -->
    <script src="http://davidstutz.github.io/bootstrap-multiselect/dist/js/bootstrap-multiselect.js"></script>

    <!-- Bootstrap multiselect -->
    <script src="ajax.js"></script>

    <!-- Initialize the plugin: -->
    <script type="text/javascript">
      $(document).ready(function() {

        $('#example-getting-started').multiselect();

      });
    </script>

  </body>
</html>

In your ajax.js page please add

$(document).ready(function () {
  $(".btnSubmit").on('click',(function(event) {
    var formData = new FormData($('#myForm')[0]);
    $.ajax({
      url: "action.php",
      type: "POST",
      data: formData,
      contentType: false,
      cache: false,
      processData:false,
      success: function(data)
      {
        $("#result").html(data);

        // To clear the selected options
        var select = $("#example-getting-started");
        select.children().remove();
        if (data.d) {
          $(data.d).each(function(key,value) {
            $("#example-getting-started").append($("<option></option>").val(value.State_id).html(value.State_name));
          });
        }
        $('#example-getting-started').multiselect({includeSelectAllOption: true});
        $("#example-getting-started").multiselect('refresh');

      },
      error: function()
      {
        console.log("failed to send the data");
      }
    });
  }));
});

In your action.php page add

  echo "<b>You selected :</b>";

  for($i=0;$i<=count($_POST['categories']);$i++){

    echo $_POST['categories'][$i]."<br>";

  }

Android Studio: Gradle - build fails -- Execution failed for task ':dexDebug'

I had the same problem, you should do:

File -> Invalidate Caches / Restart

How to modify a specified commit?

I solved this,

1) by creating new commit with changes i want..

r8gs4r commit 0

2) i know which commit i need to merge with it. which is commit 3.

so, git rebase -i HEAD~4 # 4 represents recent 4 commit (here commit 3 is in 4th place)

3) in interactive rebase recent commit will located at bottom. it will looks alike,

pick q6ade6 commit 3
pick vr43de commit 2
pick ac123d commit 1
pick r8gs4r commit 0

4) here we need to rearrange commit if you want to merge with specific one. it should be like,

parent
|_child

pick q6ade6 commit 3
f r8gs4r commit 0
pick vr43de commit 2
pick ac123d commit 1

after rearrange you need to replace p pick with f (fixup will merge without commit message) or s (squash merge with commit message can change in run time)

and then save your tree.

now merge done with existing commit.

Note: Its not preferable method unless you're maintain on your own. if you have big team size its not a acceptable method to rewrite git tree will end up in conflicts which you know other wont. if you want to maintain you tree clean with less commits can try this and if its small team otherwise its not preferable.....

How to Get the Query Executed in Laravel 5? DB::getQueryLog() Returning Empty Array

I think the answer located in this article: https://arjunphp.com/laravel-5-5-log-eloquent-queries/

is fast and simple to achieve query logging.

You just have to add to the AppServiceProvider in the boot method a callback to listen to DB queries:

namespace App\Providers;

use DB;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    public function boot()
    {
        DB::listen(function($query) {
            logger()->info($query->sql . print_r($query->bindings, true));
        });
    }
}

How do I increase the scrollback buffer in a running screen session?

WARNING: setting this value too high may cause your system to experience a significant hiccup. The higher the value you set, the more virtual memory is allocated to the screen process when initiating the screen session. I set my ~/.screenrc to "defscrollback 123456789" and when I initiated a screen, my entire system froze up for a good 10 minutes before coming back to the point that I was able to kill the screen process (which was consuming 16.6GB of VIRT mem by then).

How to clear the interpreter console?

Wiper is cool, good thing about it is I don't have to type '()' around it. Here is slight variation to it

# wiper.py
import os
class Cls(object):
    def __repr__(self):
        os.system('cls')
        return ''

The usage is quite simple:

>>> cls = Cls()
>>> cls # this will clear console.

How to get a MemoryStream from a Stream in .NET?

In .NET 4, you can use Stream.CopyTo to copy a stream, instead of the home-brew methods listed in the other answers.

MemoryStream _ms;

public MyClass(Stream sourceStream)

    _ms = new MemoryStream();
    sourceStream.CopyTo(_ms);
}

jQuery: how to scroll to certain anchor/div on page load?

Have a look at this

Appending the #value into the address is default behaviour that browsers such as IE use to identify named anchor positions on the page, seeing this comes from Netscape.

You can intercept it and remove it, read this article.

Text overwrite in visual studio 2010

Ran into this issue with Parallels and VS 2013. Command + Insert also fixed it in my setup, in addition to the accepted answer. On my Windows USB keyboard Command == WindowsKey.

Android: Storing username and password?

You should use the Android AccountManager. It's purpose-built for this scenario. It's a little bit cumbersome but one of the things it does is invalidate the local credentials if the SIM card changes, so if somebody swipes your phone and throws a new SIM in it, your credentials won't be compromised.

This also gives the user a quick and easy way to access (and potentially delete) the stored credentials for any account they have on the device, all from one place.

SampleSyncAdapter (like @Miguel mentioned) is an example that makes use of stored account credentials.

How to count lines in a document?

I saw this question while I was looking for a way to count multiple files lines, so if you want to count multiple file lines of a .txt file you can do this,

cat *.txt | wc -l

it will also run on one .txt file ;)

Remove all multiple spaces in Javascript and replace with single space

You can also replace without a regular expression.

while(str.indexOf('  ')!=-1)str.replace('  ',' ');

PHP read and write JSON from file

The sample for reading and writing JSON in PHP:

$json = json_decode(file_get_contents($file),TRUE);

$json[$user] = array("first" => $first, "last" => $last);

file_put_contents($file, json_encode($json));

How to make an alert dialog fill 90% of screen size?

Just give the AlertDialog this theme

<style name="DialogTheme" parent="Theme.MaterialComponents.Light.Dialog.MinWidth">
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="android:windowMinWidthMajor">90%</item>
    <item name="android:windowMinWidthMinor">90%</item>
</style>

Show/hide forms using buttons and JavaScript

Would you want the same form with different parts, showing each part accordingly with a button?

Here an example with three steps, that is, three form parts, but it is expandable to any number of form parts. The HTML characters &laquo; and &raquo; just print respectively « and » which might be interesting for the previous and next button characters.

_x000D_
_x000D_
shows_form_part(1)_x000D_
_x000D_
/* this function shows form part [n] and hides the remaining form parts */_x000D_
function shows_form_part(n){_x000D_
  var i = 1, p = document.getElementById("form_part"+1);_x000D_
  while (p !== null){_x000D_
    if (i === n){_x000D_
      p.style.display = "";_x000D_
    }_x000D_
    else{_x000D_
      p.style.display = "none";_x000D_
    }_x000D_
    i++;_x000D_
    p = document.getElementById("form_part"+i);_x000D_
  }_x000D_
}_x000D_
_x000D_
/* this is called at the last step using info filled during the previous steps*/_x000D_
function calc_sum() {_x000D_
  var sum =_x000D_
    parseInt(document.getElementById("num1").value) +_x000D_
    parseInt(document.getElementById("num2").value) +_x000D_
    parseInt(document.getElementById("num3").value);_x000D_
_x000D_
  alert("The sum is: " + sum);_x000D_
}
_x000D_
<div id="form_part1">_x000D_
  Part 1<br>_x000D_
  <input type="number" value="1" id="num1"><br>_x000D_
  <button type="button" onclick="shows_form_part(2)">&raquo;</button>_x000D_
</div>_x000D_
_x000D_
<div id="form_part2">_x000D_
  Part 2<br>_x000D_
  <input type="number" value="2" id="num2"><br>_x000D_
  <button type="button" onclick="shows_form_part(1)">&laquo;</button>_x000D_
  <button type="button" onclick="shows_form_part(3)">&raquo;</button>_x000D_
</div>_x000D_
_x000D_
<div id="form_part3">_x000D_
  Part 3<br>_x000D_
  <input type="number" value="3" id="num3"><br>_x000D_
  <button type="button" onclick="shows_form_part(2)">&laquo;</button>_x000D_
  <button type="button" onclick="calc_sum()">Sum</button>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Using Java 8's Optional with Stream::flatMap

Null is supported by the Stream provided My library AbacusUtil. Here is code:

Stream.of(things).map(e -> resolve(e).orNull()).skipNull().first();

Change EditText hint color when using TextInputLayout

Use TextInputLayout.setDefaultHintTextColor

Converting a view to Bitmap without displaying it in Android?

Try this,

/**
 * Draw the view into a bitmap.
 */
public static Bitmap getViewBitmap(View v) {
    v.clearFocus();
    v.setPressed(false);

    boolean willNotCache = v.willNotCacheDrawing();
    v.setWillNotCacheDrawing(false);

    // Reset the drawing cache background color to fully transparent
    // for the duration of this operation
    int color = v.getDrawingCacheBackgroundColor();
    v.setDrawingCacheBackgroundColor(0);

    if (color != 0) {
        v.destroyDrawingCache();
    }
    v.buildDrawingCache();
    Bitmap cacheBitmap = v.getDrawingCache();
    if (cacheBitmap == null) {
        Log.e(TAG, "failed getViewBitmap(" + v + ")", new RuntimeException());
        return null;
    }

    Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);

    // Restore the view
    v.destroyDrawingCache();
    v.setWillNotCacheDrawing(willNotCache);
    v.setDrawingCacheBackgroundColor(color);

    return bitmap;
}

Format of the initialization string does not conform to specification starting at index 0

Check your connection string like I forget to add services.AddDbContext<dbsContext>(options => options.UseSqlServer("Default"));

It causes the error and here when I add Configuration.GetConnectionString, then it solves the issue

like now the connection is:

services.AddDbContext<dbsContext>(options => options.UseSqlServer(Configuration.GetConnectionString("Default")));

works fine (This problem is solved for .net core)

Query to get all rows from previous month

Here's another alternative. Assuming you have an indexed DATE or DATETIME type field, this should use the index as the formatted dates will be type converted before the index is used. You should then see a range query rather than an index query when viewed with EXPLAIN.

SELECT
    * 
FROM
    table
WHERE 
    date_created >= DATE_FORMAT( CURRENT_DATE - INTERVAL 1 MONTH, '%Y/%m/01' ) 
AND
    date_created < DATE_FORMAT( CURRENT_DATE, '%Y/%m/01' )

Proper way to set response status and JSON content in a REST API made with nodejs and express

You could do this

            return res.status(201).json({
                statusCode: req.statusCode,
                method: req.method,
                message: 'Question has been added'
            });

Is the Javascript date object always one day off?

nevermind, didn't notice the GMT -0400, wich causes the date to be yesterday

You could try to set a default "time" to be 12:00:00

Why is my Button text forced to ALL CAPS on Lollipop?

This is fixable in the application code by setting the button's TransformationMethod, e.g.

mButton.setTransformationMethod(null);

UIScrollView scroll to bottom programmatically

If you somehow change scrollView contentSize (ex. add something to stackView which is inside scrollView) you must call scrollView.layoutIfNeeded() before scrolling, otherwise it does nothing.

Example:

scrollView.layoutIfNeeded()
let bottomOffset = CGPoint(x: 0, y: scrollView.contentSize.height - scrollView.bounds.size.height + scrollView.contentInset.bottom)
if(bottomOffset.y > 0) {
    scrollView.setContentOffset(bottomOffset, animated: true)
}

Auto populate columns in one sheet from another sheet

In Google Sheets you can use =ArrayFormula(Sheet1!B2:B)on the first cell and it will populate all column contents not sure if that will work in excel

Python - Module Not Found

All modules in Python have to have a certain directory structure. You can find details here.

Create an empty file called __init__.py under the model directory, such that your directory structure would look something like that:

.
+-- project
    +-- src
        +-- hello-world.py
        +-- model
            +-- __init__.py
            +-- order.py

Also in your hello-world.py file change the import statement to the following:

from model.order import SellOrder

That should fix it

P.S.: If you are placing your model directory in some other location (not in the same directory branch), you will have to modify the python path using sys.path.

How do I get countifs to select all non-blank cells in Excel?

You can try this :

=COUNTIF(Data!A2:A300,"<>"&"")

AngularJS - get element attributes values

Use Jquery functions

<Button id="myPselector" data-id="1234">HI</Button> 
console.log($("#myPselector").attr('data-id'));

SQL subquery with COUNT help

This is probably the easiest way, not the prettiest though:

SELECT *,
    (SELECT Count(*) FROM eventsTable WHERE columnName = 'Business') as RowCount
    FROM eventsTable
    WHERE columnName = 'Business'

This will also work without having to use a group by

SELECT *, COUNT(*) OVER () as RowCount
    FROM eventsTables
    WHERE columnName = 'Business'

How to check if a file is empty in Bash?

[[ -s file ]] --> Checks if file has size greater than 0

if [[ -s diff.txt ]]; then echo "file has something"; else echo "file is empty"; fi

If needed, this checks all the *.txt files in the current directory; and reports all the empty file:

for file in *.txt; do if [[ ! -s $file ]]; then echo $file; fi; done

ImportError: No module named dateutil.parser

On Ubuntu you may need to install the package manager pip first:

sudo apt-get install python-pip

Then install the python-dateutil package with:

sudo pip install python-dateutil

How to prevent SIGPIPEs (or handle them properly)

Another method is to change the socket so it never generates SIGPIPE on write(). This is more convenient in libraries, where you might not want a global signal handler for SIGPIPE.

On most BSD-based (MacOS, FreeBSD...) systems, (assuming you are using C/C++), you can do this with:

int set = 1;
setsockopt(sd, SOL_SOCKET, SO_NOSIGPIPE, (void *)&set, sizeof(int));

With this in effect, instead of the SIGPIPE signal being generated, EPIPE will be returned.

PopupWindow $BadTokenException: Unable to add window -- token null is not valid

  @Override
protected void onCreate(Bundle savedInstanceState) {
    View view = LayoutInflater.from(mContext).inflate(R.layout.popup_window_layout, new LinearLayout(mContext), true);
    popupWindow = new PopupWindow(view, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
    popupWindow.setContentView(view);
}

   @Override
public void onWindowFocusChanged(boolean hasFocus) {
    if (hasFocus) {
        popupWindow.showAtLocation(parentView, Gravity.BOTTOM, 0, 0);
    }
}

the correct way is popupwindow.show() at onWindowFocusChanged().

Is there a built-in function to print all the current properties and values of an object?

If you're using this for debugging, and you just want a recursive dump of everything, the accepted answer is unsatisfying because it requires that your classes have good __str__ implementations already. If that's not the case, this works much better:

import json
print(json.dumps(YOUR_OBJECT, 
                 default=lambda obj: vars(obj),
                 indent=1))

remove legend title in ggplot

You were almost there : just add theme(legend.title=element_blank())

ggplot(df, aes(x, y, colour=g)) +
  geom_line(stat="identity") + 
  theme(legend.position="bottom") +
  theme(legend.title=element_blank())

This page on Cookbook for R gives plenty of details on how to customize legends.

Recursive Fibonacci

int fib(int x) 
{
    if (x < 2)
      return x;
    else 
      return (fib(x - 1) + fib(x - 2));
}

apache mod_rewrite is not working or not enabled

It's working.

my solution is:

1.create a test.conf into /etc/httpd/conf.d/test.conf

2.wrote some rule, like:

<Directory "/var/www/html/test">
RewriteEngine On
RewriteRule ^link([^/]*).html$ rewrite.php?link=$1 [L]
</Directory>

3.restart your Apache server.

4.try again yourself.

Bootstrap 4 - Inline List?

Shouldn't it be just the .list-group? See below,

<ul class="list-group">
  <li class="list-group-item active">Cras justo odio</li>
  <li class="list-group-item">Dapibus ac facilisis in</li>
  <li class="list-group-item">Morbi leo risus</li>
  <li class="list-group-item">Porta ac consectetur ac</li>
  <li class="list-group-item">Vestibulum at eros</li>
</ul>

Reference: Bootstrap 4 Basic Example of a List group

How to correctly dismiss a DialogFragment?

I found that when my fragment was defined in the navigation graph with a <fragment> tag (for a full screen dialogfragment), the dialogfragment would not dismiss with the dismiss() command. Instead, I had to pop the back stack:

findNavController(getActivity(), R.id.nav_host_fragment).popBackStack();

However, if the same dialogfragment was defined in the navigation graph with a <dialog> tag, dismiss() works fine.

Could not load file or assembly Exception from HRESULT: 0x80131040

Check if the project having HRESULT: 0x80131040 error is being used/referenced by any project. If yes, kindly check if these project have similar .dll being referenced and the version is the same. If they're are not of same version number, then it is causing the said error.

Command CompileSwift failed with a nonzero exit code in Xcode 10

I had this issue and changing the Compilation Mode setting for the project from Incremental to Whole Module fixed it for me.

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How to draw a graph in PHP?

There are a number of libraries available for generating graphs.

More are listed above and here.

CSS Input with width: 100% goes outside parent's bound

You also have an error in your css with the exclamation point in this line:

background:rgb(242, 242, 242);!important;

remove the semi-colon before it. However, !important should be used rarely and can largely be avoided.

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

By default std::map (and std::set) use operator< to determine sorting. Therefore, you need to define operator< on your class.

Two objects are deemed equivalent if !(a < b) && !(b < a).

If, for some reason, you'd like to use a different comparator, the third template argument of the map can be changed, to std::greater, for example.

Difference between using "chmod a+x" and "chmod 755"

Yes - different

chmod a+x will add the exec bits to the file but will not touch other bits. For example file might be still unreadable to others and group.

chmod 755 will always make the file with perms 755 no matter what initial permissions were.

This may or may not matter for your script.

Resource interpreted as Document but transferred with MIME type application/json warning in Chrome Developer Tools

This happened to me, and once I removed this: enctype="multipart/form-data" It started working without the warning