Programs & Examples On #Dtrace

DTrace is a comprehensive dynamic tracing framework for the Solaris Operating Environment, Mac OS X 10.5+ and FreeBSD.

pip is not able to install packages correctly: Permission denied error

On a Mac, you need to use this command:

STATIC_DEPS=true sudo pip install lxml

Installing PIL with pip

This works for me:

apt-get install python-dev
apt-get install libjpeg-dev
apt-get install libjpeg8-dev
apt-get install libpng3
apt-get install libfreetype6-dev
ln -s /usr/lib/i386-linux-gnu/libfreetype.so /usr/lib
ln -s /usr/lib/i386-linux-gnu/libjpeg.so /usr/lib
ln -s /usr/lib/i386-linux-gnu/libz.so /usr/lib

pip install PIL  --allow-unverified PIL --allow-all-external

Error: The 'brew link' step did not complete successfully

My problem had a slightly different solution. The directory in which brew wanted to create the symlinks were not owned by the current user.

ls -la /usr/local/bin/lib/node | grep node yielded:

drwxr-xr-x    3 24561  wheel   102 May  4  2012 node
drwxr-xr-x    7 24561  wheel   238 Sep 18 16:37 node_modules

For me, the following fixed it:

sudo chown $(users) /usr/local/bin/lib/node_modules
sudo chown $(users) /usr/local/bin/lib/node

ps. $(users) will get expanded to your username, went a little out of my way to help out lazy copy pasters ;)

How to make JQuery-AJAX request synchronous

Can you try this,

var ajaxSubmit = function(formE1) {

            var password = $.trim($('#employee_password').val());

             $.ajax({
                type: "POST",
                async: "false",
                url: "checkpass.php",
                data: "password="+password,
                success: function(html) {
                    var arr=$.parseJSON(html);
                    if(arr == "Successful")
                    { 
                         **$("form[name='form']").submit();**
                        return true;
                    }
                    else
                    {    return false;
                    }
                }
            });
              **return false;**
        }

Get all directories within directory nodejs

List directories using a path.

function getDirectories(path) {
  return fs.readdirSync(path).filter(function (file) {
    return fs.statSync(path+'/'+file).isDirectory();
  });
}

C# Creating an array of arrays

This loops vertically but might work for you.

int rtn = 0;    
foreach(int[] L in lists){
    for(int i = 0; i<L.Length;i++){
          rtn = L[i];
      //Do something with rtn
    }
}

How to convert <font size="10"> to px?

This cannot be answered that easily. It depends on the font used and the points per inch (ppi). This should give an overview of the problem.

Failed to build gem native extension (installing Compass)

For macOS 10.14 Mojave, make sure you have already installed command line tools via xcode-select --install and the run the following command to install std headers.

sudo open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

Now try your command again.

Getting value from a cell from a gridview on RowDataBound event

First you need to wrap your code in a Label or Literal control so that you can reference it properly. What's happening is that there's no way for the system to keep track of it, because there's no control associated with the text. It's the control's responsibility to add its contents to viewstate.

You need to use gridView.FindControl("controlName"); to get the control in the row. From there you can get at its properties including Text.

You can also get at the DataItem property of the Row in question and cast it to the appropriate type and extract the information directly.

Add a column to existing table and uniquely number them on MS SQL Server

And the Postgres equivalent (second line is mandatory only if you want "id" to be a key):

ALTER TABLE tableName ADD id SERIAL;
ALTER TABLE tableName ADD PRIMARY KEY (id);

Creating a custom JButton in Java

I haven't done SWING development since my early CS classes but if it wasn't built in you could just inherit javax.swing.AbstractButton and create your own. Should be pretty simple to wire something together with their existing framework.

Node / Express: EADDRINUSE, Address already in use - Kill server

Here is a one liner (replace 3000 with a port or a config variable):

kill $(lsof -t -i:3000)

How do you see the entire command history in interactive Python?

In IPython %history -g should give you the entire command history. The default configuration also saves your history into a file named .python_history in your user directory.

Angular cli generate a service and include the provider in one step

slight change in syntax from the accepted answer for Angular 5 and angular-cli 1.7.0

ng g service backendApi --module=app.module

Web API Routing - api/{controller}/{action}/{id} "dysfunctions" api/{controller}/{id}

The route engine uses the same sequence as you add rules into it. Once it gets the first matched rule, it will stop checking other rules and take this to search for controller and action.

So, you should:

  1. Put your specific rules ahead of your general rules(like default), which means use RouteTable.Routes.MapHttpRoute to map "WithActionApi" first, then "DefaultApi".

  2. Remove the defaults: new { id = System.Web.Http.RouteParameter.Optional } parameter of your "WithActionApi" rule because once id is optional, url like "/api/{part1}/{part2}" will never goes into "DefaultApi".

  3. Add an named action to your "DefaultApi" to tell the route engine which action to enter. Otherwise once you have more than one actions in your controller, the engine won't know which one to use and throws "Multiple actions were found that match the request: ...". Then to make it matches your Get method, use an ActionNameAttribute.

So your route should like this:

// Map this rule first
RouteTable.Routes.MapRoute(
     "WithActionApi",
     "api/{controller}/{action}/{id}"
 );

RouteTable.Routes.MapRoute(
    "DefaultApi",
    "api/{controller}/{id}",
    new { action="DefaultAction", id = System.Web.Http.RouteParameter.Optional }
);

And your controller:

[ActionName("DefaultAction")] //Map Action and you can name your method with any text
public string Get(int id)
{
    return "object of id id";
}        

[HttpGet]
public IEnumerable<string> ByCategoryId(int id)
{
    return new string[] { "byCategory1", "byCategory2" };
}

Calling one Activity from another in Android

I used following code on my sample application to start new activity.

Button next = (Button) findViewById(R.id.TEST);
next.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        Intent myIntent = new Intent( view.getContext(), MyActivity.class);
        startActivityForResult(myIntent, 0);
    }
});

How do you get a directory listing sorted by creation date in python?

Turns out os.listdir sorts by last modified but in reverse so you can do:

import os
last_modified=os.listdir()[::-1]

Use YAML with variables

if your requirement is like parsing an replacing multiple variable and then use it as a hash/or anything then you can do something like this

require 'yaml'
require 'json'
yaml = YAML.load_file("xxxx.yaml")
blueprint = yaml.to_json % { var_a: "xxxx", var_b: "xxxx"}
hash = JSON.parse(blueprint)

inside the yaml just put variables like this

"%{var_a}"

PHP: convert spaces in string into %20?

The plus sign is the historic encoding for a space character in URL parameters, as documented in the help for the urlencode() function.

That same page contains the answer you need - use rawurlencode() instead to get RFC 3986 compatible encoding.

Compile/run assembler in Linux?

3 syntax (nasm, tasm, gas ) in 1 assembler, yasm.

http://www.tortall.net/projects/yasm/

Can Rails Routing Helpers (i.e. mymodel_path(model)) be Used in Models?

Any logic having to do with what is displayed in the view should be delegated to a helper method, as methods in the model are strictly for handling data.

Here is what you could do:

# In the helper...

def link_to_thing(text, thing)
  (thing.url?) ? link_to(text, thing_path(thing)) : link_to(text, thing.url)
end

# In the view...

<%= link_to_thing("text", @thing) %>

How to bind a List to a ComboBox?

Try something like this:

yourControl.DataSource = countryInstance.Cities;

And if you are using WebForms you will need to add this line:

yourControl.DataBind();

.gitignore after commit

However, will it automatically remove these committed files from the repository?

No.

The 'best' recipe to do this is using git filter-branch as written about here:

The man page for git-filter-branch contains comprehensive examples.

Note You'll be re-writing history. If you had published any revisions containing the accidentally added files, this could create trouble for users of those public branches. Inform them, or perhaps think about how badly you need to remove the files.

Note In the presence of tags, always use the --tag-name-filter cat option to git filter-branch. It never hurts and will save you the head-ache when you realize later taht you needed it

Visual Studio 2013 Install Fails: Program Compatibility Mode is on (Windows 10)

If you disable the Program Compatibility Mode and the problem persists, copy the content of ISO to a local path and try install with a simple double click

php.ini & SMTP= - how do you pass username & password

PHP does have authentication on the mail-command!

The following is working for me on WAMPSERVER (windows, php 5.2.17)

php.ini

[mail function]
; For Win32 only.
SMTP = mail.yourserver.com
smtp_port = 25
auth_username = smtp-username
auth_password = smtp-password
sendmail_from = [email protected]

Converting strings to floats in a DataFrame

Here is an example

                            GHI             Temp  Power Day_Type
2016-03-15 06:00:00 -7.99999952505459e-7    18.3    0   NaN
2016-03-15 06:01:00 -7.99999952505459e-7    18.2    0   NaN
2016-03-15 06:02:00 -7.99999952505459e-7    18.3    0   NaN
2016-03-15 06:03:00 -7.99999952505459e-7    18.3    0   NaN
2016-03-15 06:04:00 -7.99999952505459e-7    18.3    0   NaN

but if this is all string values...as was in my case... Convert the desired columns to floats:

df_inv_29['GHI'] = df_inv_29.GHI.astype(float)
df_inv_29['Temp'] = df_inv_29.Temp.astype(float)
df_inv_29['Power'] = df_inv_29.Power.astype(float)

Your dataframe will now have float values :-)

Is there a way to cast float as a decimal without rounding and preserving its precision?

Have you tried:

SELECT Cast( 2.555 as decimal(53,8))

This would return 2.55500000. Is that what you want?

UPDATE:

Apparently you can also use SQL_VARIANT_PROPERTY to find the precision and scale of a value. Example:

SELECT SQL_VARIANT_PROPERTY(Cast( 2.555 as decimal(8,7)),'Precision'),
SQL_VARIANT_PROPERTY(Cast( 2.555 as decimal(8,7)),'Scale')

returns 8|7

You may be able to use this in your conversion process...

Python object deleting itself

Indeed, Python does garbage collection through reference counting. As soon as the last reference to an object falls out of scope, it is deleted. In your example:

a = A()
a.kill()

I don't believe there's any way for variable 'a' to implicitly set itself to None.

SQL Server: Best way to concatenate multiple columns?

If the fields are nullable, then you'll have to handle those nulls. Remember that null is contagious, and concat('foo', null) simply results in NULL as well:

SELECT CONCAT(ISNULL(column1, ''),ISNULL(column2,'')) etc...

Basically test each field for nullness, and replace with an empty string if so.

Resource from src/main/resources not found after building with maven

Once after we build the jar will have the resource files under BOOT-INF/classes or target/classes folder, which is in classpath, use the below method and pass the file under the src/main/resources as method call getAbsolutePath("certs/uat_staging_private.ppk"), even we can place this method in Utility class and the calling Thread instance will be taken to load the ClassLoader to get the resource from class path.

 public String getAbsolutePath(String fileName) throws IOException {
      return Thread.currentThread().getContextClassLoader().getResource(fileName).getFile();
  }

enter image description here enter image description here

we can add the below tag to tag in pom.xml to include these resource files to build target/classes folder

<resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.ppk</include>
            </includes>
        </resource>
</resources>

Hibernate Group by Criteria Object

GroupBy using in Hibernate

This is the resulting code

public Map getStateCounts(final Collection ids) {
    HibernateSession hibernateSession = new HibernateSession();
    Session session = hibernateSession.getSession();
    Criteria criteria = session.createCriteria(DownloadRequestEntity.class)
            .add(Restrictions.in("id", ids));
    ProjectionList projectionList = Projections.projectionList();
    projectionList.add(Projections.groupProperty("state"));
    projectionList.add(Projections.rowCount());
    criteria.setProjection(projectionList);
    List results = criteria.list();
    Map stateMap = new HashMap();
    for (Object[] obj : results) {
        DownloadState downloadState = (DownloadState) obj[0];
        stateMap.put(downloadState.getDescription().toLowerCase() (Integer) obj[1]);
    }
    hibernateSession.closeSession();
    return stateMap;
}

How to format a number as percentage in R?

Check out the percent function from the formattable package:

library(formattable)
x <- c(0.23, 0.95, 0.3)
percent(x)
[1] 23.00% 95.00% 30.00%

Fatal error: Maximum execution time of 300 seconds exceeded

For Xampp Users

1. Go to C:\xampp\phpMyAdmin\libraries
2. Open config.default.php
3. Search for $cfg['ExecTimeLimit'] = 300;
4. Change to the Value 300 to 0 or set a larger value
5. Save the file and restart the server
6. OR Set the ini_set('MAX_EXECUTION_TIME', '-1'); at the beginning of your script you can add.

Difference between EXISTS and IN in SQL?

I found that using EXISTS keyword is often really slow (that is very true in Microsoft Access). I instead use the join operator in this manner : should-i-use-the-keyword-exists-in-sql

Java Desktop application: SWT vs. Swing

If you plan to build a full functional applications with more than a handful of features, I will suggest to jump right to using Eclipse RCP as the framework.

If your application won't grow too big or your requirements are just too unique to be handled by a normal business framework, you can safely jump with Swing.

At the end of the day, I'd suggest you to try both technologies to find the one suit you better. Like Netbeans vs Eclipse vs IntelliJ, there is no the absolute correct answer here and both frameworks have their own drawbacks.

Pro Swing:

  • more experts
  • more Java-like (almost no public field, no need to dispose on resource)

Pro SWT:

  • more OS native
  • faster

How to break out from foreach loop in javascript

Use a for loop instead of .forEach()

var myObj = [{"a": "1","b": null},{"a": "2","b": 5}]
var result = false

for(var call of myObj) {
    console.log(call)
    
    var a = call['a'], b = call['b']
     
    if(a == null || b == null) {
        result = false
        break
    }
}

Variable interpolation in the shell

Use curly braces around the variable name:

`tail -1 ${filepath}_newstap.sh`

How do I implement IEnumerable<T>

You probably do not want an explicit implementation of IEnumerable<T> (which is what you've shown).

The usual pattern is to use IEnumerable<T>'s GetEnumerator in the explicit implementation of IEnumerable:

class FooCollection : IEnumerable<Foo>, IEnumerable
{
    SomeCollection<Foo> foos;

    // Explicit for IEnumerable because weakly typed collections are Bad
    System.Collections.IEnumerator IEnumerable.GetEnumerator()
    {
        // uses the strongly typed IEnumerable<T> implementation
        return this.GetEnumerator();
    }

    // Normal implementation for IEnumerable<T>
    IEnumerator<Foo> GetEnumerator()
    {
        foreach (Foo foo in this.foos)
        {
            yield return foo;
            //nb: if SomeCollection is not strongly-typed use a cast:
            // yield return (Foo)foo;
            // Or better yet, switch to an internal collection which is
            // strongly-typed. Such as List<T> or T[], your choice.
        }

        // or, as pointed out: return this.foos.GetEnumerator();
    }
}

Write to .txt file?

FILE *fp;
char* str = "string";
int x = 10;

fp=fopen("test.txt", "w");
if(fp == NULL)
    exit(-1);
fprintf(fp, "This is a string which is written to a file\n");
fprintf(fp, "The string has %d words and keyword %s\n", x, str);
fclose(fp);

error 1265. Data truncated for column when trying to load data from txt file

The reason is that mysql expecting end of the row symbol in the text file after last specified column, and this symbol is char(10) or '\n'. Depends on operation system where text file created or if you created your text file yourself, it can be other combination (Windows uses '\r\n' (chr(13)+chr(10)) as rows separator). Thus, if you use Windows generated text file, add following suffix to your LOAD command: “ LINES TERMINATED BY '\r\n' ”. Otherwise, check how rows are separated in your text file. On default mysql expecting char(10) as rows separator.

HTTP GET request in JavaScript?

IE will cache URLs in order to make loading faster, but if you're, say, polling a server at intervals trying to get new information, IE will cache that URL and will likely return the same data set you've always had.

Regardless of how you end up doing your GET request - vanilla JavaScript, Prototype, jQuery, etc - make sure that you put a mechanism in place to combat caching. In order to combat that, append a unique token to the end of the URL you're going to be hitting. This can be done by:

var sURL = '/your/url.html?' + (new Date()).getTime();

This will append a unique timestamp to the end of the URL and will prevent any caching from happening.

Bootstrap fixed header and footer with scrolling body-content area in fluid-container

Add the following css to disable the default scroll:

body {
    overflow: hidden;
}

And change the #content css to this to make the scroll only on content body:

#content {
    max-height: calc(100% - 120px);
    overflow-y: scroll;
    padding: 0px 10%;
    margin-top: 60px;
}

See fiddle here.


Edit:

Actually, I'm not sure what was the issue you were facing, since it seems that your css is working. I have only added the HTML and the header css statement:

_x000D_
_x000D_
html {_x000D_
  height: 100%;_x000D_
}_x000D_
html body {_x000D_
  height: 100%;_x000D_
  overflow: hidden;_x000D_
}_x000D_
html body .container-fluid.body-content {_x000D_
  position: absolute;_x000D_
  top: 50px;_x000D_
  bottom: 30px;_x000D_
  right: 0;_x000D_
  left: 0;_x000D_
  overflow-y: auto;_x000D_
}_x000D_
header {_x000D_
    position: absolute;_x000D_
    left: 0;_x000D_
    right: 0;_x000D_
    top: 0;_x000D_
    background-color: #4C4;_x000D_
    height: 50px;_x000D_
}_x000D_
footer {_x000D_
    position: absolute;_x000D_
    left: 0;_x000D_
    right: 0;_x000D_
    bottom: 0;_x000D_
    background-color: #4C4;_x000D_
    height: 30px;_x000D_
}
_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<header></header>_x000D_
<div class="container-fluid body-content">_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
  Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>Lorem Ipsum<br/>_x000D_
</div>_x000D_
<footer></footer>
_x000D_
_x000D_
_x000D_

Change the Textbox height?

AutoSize, Minimum, Maximum does not give flexibility. Use multiline and handle the enter key event and suppress the keypress. Works great.

textBox1.Multiline = true;

 private void textBox1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                e.Handled = true;
                e.SuppressKeyPress = true;
            }
        }

Pass entire form as data in jQuery Ajax function

Use

serialize( )

var str = $("form").serialize();

Serialize a form to a query string, that could be sent to a server in an Ajax request.

Import Certificate to Trusted Root but not to Personal [Command Line]

There is a fairly simple answer with powershell.

Import-PfxCertificate -Password $secure_pw  -CertStoreLocation Cert:\LocalMachine\Root -FilePath certs.pfx

The trick is making a "secure" password...

$plaintext_pw = 'PASSWORD';
$secure_pw = ConvertTo-SecureString $plaintext_pw -AsPlainText -Force; 
Import-PfxCertificate -Password $secure_pw  -CertStoreLocation Cert:\LocalMachine\Root -FilePath certs.pfx;

How to add form validation pattern in Angular 2?

My solution with Angular 4.0.1: Just showing the UI for required CVC input - where the CVC must be exactly 3 digits:

    <form #paymentCardForm="ngForm">         
...
        <md-input-container align="start">
            <input #cvc2="ngModel" mdInput type="text" id="cvc2" name="cvc2" minlength="3" maxlength="3" placeholder="CVC" [(ngModel)]="paymentCard.cvc2" [disabled]="isBusy" pattern="\d{3}" required />
            <md-hint *ngIf="cvc2.errors && (cvc2.touched || submitted)" class="validation-result">
                <span [hidden]="!cvc2.errors.required && cvc2.dirty">
                    CVC is required.
                </span>
                <span [hidden]="!cvc2.errors.minlength && !cvc2.errors.maxlength && !cvc2.errors.pattern">
                    CVC must be 3 numbers.
                </span>
            </md-hint>
        </md-input-container>
...
<button type="submit" md-raised-button color="primary" (click)="confirm($event, paymentCardForm.value)" [disabled]="isBusy || !paymentCardForm.valid">Confirm</button>
</form>

Subset dataframe by multiple logical conditions of rows to remove

Try this

subset(data, !(v1 %in% c("b","d","e")))

How to uninstall Anaconda completely from macOS

The official instructions seem to be here: https://docs.anaconda.com/anaconda/install/uninstall/

but if you like me that didn't work for some reason and for some reason your conda was installed somewhere else with telling you do this:

rm -rf ~/opt

I have no idea why it was saved there but that's what did it for me.


This was useful to me in fixing my conda installation (if that is the reason you are uninstalling it in the first place like me): https://stackoverflow.com/a/60902863/1601580 that ended up fixing it for me. Not sure why conda was acting weird in the first place or installing things wrongly in the first place though...

PHP fwrite new line

Use PHP_EOL which produces \r\n or \n

$data = 'my data' . PHP_EOL . 'my data';
$fp = fopen('my_file', 'a');
fwrite($fp, $data);
fclose($fp);

// File output

my data
my data

"Could not find acceptable representation" using spring-boot-starter-web

Add below dependency to your pom.xml:

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
    <version>2.10.2</version>
</dependency>

unknown error: Chrome failed to start: exited abnormally (Driver info: chromedriver=2.9

I was trying to run selenium on Jenkins with Mocha framework using wdio. So following are the steps to solve this issue:-

Install google chrome

sudo apt-get update 

sudo apt-get install google-chrome-stable

Install chrome-driver

wget http://chromedriver.storage.googleapis.com/2.23/chromedriver_linux64.zip
unzip chromedriver_linux64.zip

Run following commands to start selenium web server

nohup sudo Xvfb :10 -ac
export DISPLAY=:10
java -jar vendor/se/selenium-server-standalone/bin/selenium-server-standalone.jar -Dwebdriver.chrome.bin="/usr/bin/google-chrome" -Dwebdriver.chrome.driver="vendor/bin/chromedriver"

After this start you tests with wdio command

wdio wdio.conf.js

insert multiple rows into DB2 database

None of the above worked for me, the only one working was

insert into tableName  
select 11, 'BALOO' from sysibm.sysdummy1 union all
select 22, nullif('','') AS nullColumn from sysibm.sysdummy1

The nullif is used since it is not possible to pass null in the select statement otherwise.

Open a local HTML file using window.open in Chrome

window.location.href = 'file://///fileserver/upload/Old_Upload/05_06_2019/THRESHOLD/BBH/Look/chrs/Delia';

Nothing Worked for me.

proper way to sudo over ssh

NOPASS in the configuration on your target machine is the solution. Continue reading at http://maestric.com/doc/unix/ubuntu_sudo_without_password

Generate Java classes from .XSD files...?

JAXB does EXACTLY what you want. It's built into the JRE/JDK starting at 1.6

Get record counts for all tables in MySQL database

I just run:

show table status;

This will give you the row count for EVERY table plus a bunch of other info. I used to use the selected answer above, but this is much easier.

I'm not sure if this works with all versions, but I'm using 5.5 with InnoDB engine.

ImportError: numpy.core.multiarray failed to import

I used Anaconda environment and had the same issue. I tried all the aforementioned approaches and, alas, it didn't help me. Accumulated the suggestions, here the way which helped me:

  1. Delete all NumPy folders in the virtual environment or in the system if you don't use a virtual environment, for example in my case:

    ~/home/anaconda3/envs//lib/python/site-packages/numpy

    ~/home/anaconda3/envs//lib/python/site-packages/numpy.libs

    ~/home/anaconda3/envs//lib/python/site-packages/numpy-.dist-info

  2. Install new Numpy with:

    pip install numpy -U

Hope, it could help in the same case

Angular CLI SASS options

Best could be ng new myApp --style=scss

Then Angular CLI will create any new component with scss for you...

Note that using scss not working in the browser as you probably know.. so we need something to compile it to css, for this reason we can use node-sass, install it like below:

npm install node-sass --save-dev

and you should be good to go!

If you using webpack, read on here:

Command line inside project folder where your existing package.json is: npm install node-sass sass-loader raw-loader --save-dev

In webpack.common.js, search for "rules:" and add this object to the end of the rules array (don't forget to add a comma to the end of the previous object):

{
  test: /\.scss$/,
  exclude: /node_modules/,
  loaders: ['raw-loader', 'sass-loader'] // sass-loader not scss-loader
}

Then in your component:

@Component({
  styleUrls: ['./filename.scss'],
})

If you want global CSS support then on the top level component (likely app.component.ts) remove encapsulation and include the SCSS:

import {ViewEncapsulation} from '@angular/core';

@Component({
  selector: 'app',
  styleUrls: ['./bootstrap.scss'],
  encapsulation: ViewEncapsulation.None,
  template: ``
})
class App {}

from Angular starter here.

How to search for a part of a word with ElasticSearch

without changing your index mappings you could do a simple prefix query that will do partial searches like you are hoping for

ie.

{
  "query": { 
    "prefix" : { "name" : "Doe" }
  }
}

https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-prefix-query.html

How to check if a file exists before creating a new file

Try

ifstream my_file("test.txt");
if (my_file)
{
 // do stuff
}

From: How to check if a file exists and is readable in C++?

or you could use boost functions.

Get user profile picture by Id

You can use following urls to obtain different sizes of profile images. Please make sure to add Facebook id to url.

Large size photo https://graph.facebook.com/{facebookId}/picture?type=large

Medium size photo https://graph.facebook.com/{facebookId}/picture?type=normal

Small size photo https://graph.facebook.com/{facebookId}/picture?type=small

Square photo https://graph.facebook.com/{facebookId}/picture?type=square

How to fix "Only one expression can be specified in the select list when the subquery is not introduced with EXISTS" error?

Try this one -

"SELECT 
       ID, Salt, password, BannedEndDate
     , (
          SELECT COUNT(1)
          FROM dbo.LoginFails l
          WHERE l.UserName = u.UserName
               AND IP = '" + Request.ServerVariables["REMOTE_ADDR"] + "'
      ) AS cnt
FROM dbo.Users u
WHERE u.UserName = '" + LoginModel.Username + "'"

How to do a simple file search in cmd

dir /b/s *.txt  

searches for all txt file in the directory tree. Before using it just change the directory to root using

cd/

you can also export the list to a text file using

dir /b/s *.exe >> filelist.txt

and search within using

type filelist.txt | find /n "filename"

EDIT 1: Although this dir command works since the old dos days but Win7 added something new called Where

where /r c:\Windows *.exe *.dll

will search for exe & dll in the drive c:\Windows as suggested by @SPottuit you can also copy the output to the clipboard with

where /r c:\Windows *.exe |clip

just wait for the prompt to return and don't copy anything until then.

EDIT 2: If you are searching recursively and the output is big you can always use more to enable paging, it will show -- More -- at the bottom and will scroll to the next page once you press SPACE or moves line by line on pressing ENTER

where /r c:\Windows *.exe |more

For more help try

where/?

Visual Studio: How to break on handled exceptions?

Check Managing Exceptions with the Debugger page, it explains how to set this up.

Essentially, here are the steps (during debugging):

  1. On the Debug menu, click Exceptions.

  2. In the Exceptions dialog box, select Thrown for an entire category of exceptions, for example, Common Language Runtime Exceptions.

    -or-

    Expand the node for a category of exceptions, for example, Common Language Runtime Exceptions, and select Thrown for a specific exception within that category.

What is the difference between <jsp:include page = ... > and <%@ include file = ... >?

One is a static import (<%=@ include...>"), the other is a dynamic one (jsp:include). It will affect for example the path you gonna have to specify for your included file. A little research on Google will tell you more.

Should I use @EJB or @Inject

Injection already existed in Java EE 5 with the @Resource, @PersistentUnit or @EJB annotations, for example. But it was limited to certain resources (datasource, EJB . . .) and into certain components (Servlets, EJBs, JSF backing bean . . .). With CDI you can inject nearly anything anywhere thanks to the @Inject annotation.

How do you display code snippets in MS Word preserving format and syntax highlighting?

If you are using Android Studio, you can simply copy and paste, and the code aspect is going to be preserved and the colors as well. Simple enough!

pandas read_csv index_col=None not working with delimiters at the end of each line

Re: craigts's response, for anyone having trouble with using either False or None parameters for index_col, such as in cases where you're trying to get rid of a range index, you can instead use an integer to specify the column you want to use as the index. For example:

df = pd.read_csv('file.csv', index_col=0)

The above will set the first column as the index (and not add a range index in my "common case").

Update

Given the popularity of this answer, I thought i'd add some context/ a demo:

# Setting up the dummy data
In [1]: df = pd.DataFrame({"A":[1, 2, 3], "B":[4, 5, 6]})

In [2]: df
Out[2]:
   A  B
0  1  4
1  2  5
2  3  6

In [3]: df.to_csv('file.csv', index=None)
File[3]:
A  B
1  4
2  5
3  6

Reading without index_col or with None/False will all result in a range index:

In [4]: pd.read_csv('file.csv')
Out[4]:
   A  B
0  1  4
1  2  5
2  3  6

# Note that this is the default behavior, so the same as In [4]
In [5]: pd.read_csv('file.csv', index_col=None)
Out[5]:
   A  B
0  1  4
1  2  5
2  3  6

In [6]: pd.read_csv('file.csv', index_col=False)
Out[6]:
   A  B
0  1  4
1  2  5
2  3  6

However, if we specify that "A" (the 0th column) is actually the index, we can avoid the range index:

In [7]: pd.read_csv('file.csv', index_col=0)
Out[7]:
   B
A
1  4
2  5
3  6

ToggleClass animate jQuery?

You should look at the toggle function found on jQuery. This will allow you to specify an easing method to define how the toggle works.

slideToggle will only slide up and down, not left/right if that's what you are looking for.

If you need the class to be toggled as well you can deifine that in the toggle function with a:

$(this).closest('article').toggle('slow', function() {
    $(this).toggleClass('expanded');
});

How to exit a 'git status' list in a terminal?

Please try this steps in git bash, It may help you.

  1. CTRL + C
  2. :qa!

Android EditText for password with android:hint

If you set

android:inputType="textPassword"

this property and if you provide number as password example "1234567" it will take it as "123456/" the seventh character is not taken. Thats why instead of this approach use

android:password="true"

property which allows you to enter any type of password without any restriction.

If you want to provide hint use

android:hint="hint text goes here"

example:

android:hint="password"

How to execute UNION without sorting? (SQL)

I notice this question gets quite a lot of views so I'll first address a question you didn't ask!

Regarding the title. To achieve a "Sql Union All with “distinct”" then simply replace UNION ALL with UNION. This has the effect of removing duplicates.

For your specific question, given the clarification "The first query should have "priority", so duplicates should be removed from bottom" you can use

SELECT col1,
       col2,
       MIN(grp) AS source_group
FROM   (SELECT 1 AS grp,
               col1,
               col2
        FROM   t1
        UNION ALL
        SELECT 2 AS grp,
               col1,
               col2
        FROM   t2) AS t
GROUP  BY col1,
          col2
ORDER  BY MIN(grp),
          col1  

Bootstrap 4 File Input

For changing the language of the file browser:
As an alternate to what ZimSystem mentioned (override the CSS), a more elegant solution is suggested by the bootstrap docs: build your custom bootstrap styles by adding languages in SCSS
Read about it here: https://getbootstrap.com/docs/4.0/components/forms/#file-browser

Note: you need to have the lang attribute properly set in your document for this to work

For updating the value on file selection:
You could do it with inline js like this:

   <label class="custom-file">
      <input type="file" id="myfile" class="custom-file-input" onchange="$(this).next().after().text($(this).val().split('\\').slice(-1)[0])">
      <span class="custom-file-control"></span>
   </label>

Note: the .split('\\').slice(-1)[0] part removes the C:\fakepath\ prefix

How can I get a process handle by its name in C++?

The following code shows how you can use toolhelp and OpenProcess to get a handle to the process. Error handling removed for brevity.

HANDLE GetProcessByName(PCSTR name)
{
    DWORD pid = 0;

    // Create toolhelp snapshot.
    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    PROCESSENTRY32 process;
    ZeroMemory(&process, sizeof(process));
    process.dwSize = sizeof(process);

    // Walkthrough all processes.
    if (Process32First(snapshot, &process))
    {
        do
        {
            // Compare process.szExeFile based on format of name, i.e., trim file path
            // trim .exe if necessary, etc.
            if (string(process.szExeFile) == string(name))
            {
               pid = process.th32ProcessID;
               break;
            }
        } while (Process32Next(snapshot, &process));
    }

    CloseHandle(snapshot);

    if (pid != 0)
    {
         return OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);
    }

    // Not found


       return NULL;
}

How to use '-prune' option of 'find' in sh?

Beware that -prune does not prevent descending into any directory as some have said. It prevents descending into directories that match the test it's applied to. Perhaps some examples will help (see the bottom for a regex example). Sorry for this being so lengthy.

$ find . -printf "%y %p\n"    # print the file type the first time FYI
d .
f ./test
d ./dir1
d ./dir1/test
f ./dir1/test/file
f ./dir1/test/test
d ./dir1/scripts
f ./dir1/scripts/myscript.pl
f ./dir1/scripts/myscript.sh
f ./dir1/scripts/myscript.py
d ./dir2
d ./dir2/test
f ./dir2/test/file
f ./dir2/test/myscript.pl
f ./dir2/test/myscript.sh

$ find . -name test
./test
./dir1/test
./dir1/test/test
./dir2/test

$ find . -prune
.

$ find . -name test -prune
./test
./dir1/test
./dir2/test

$ find . -name test -prune -o -print
.
./dir1
./dir1/scripts
./dir1/scripts/myscript.pl
./dir1/scripts/myscript.sh
./dir1/scripts/myscript.py
./dir2

$ find . -regex ".*/my.*p.$"
./dir1/scripts/myscript.pl
./dir1/scripts/myscript.py
./dir2/test/myscript.pl

$ find . -name test -prune -regex ".*/my.*p.$"
(no results)

$ find . -name test -prune -o -regex ".*/my.*p.$"
./test
./dir1/test
./dir1/scripts/myscript.pl
./dir1/scripts/myscript.py
./dir2/test

$ find . -regex ".*/my.*p.$" -a -not -regex ".*test.*"
./dir1/scripts/myscript.pl
./dir1/scripts/myscript.py

$ find . -not -regex ".*test.*"                   .
./dir1
./dir1/scripts
./dir1/scripts/myscript.pl
./dir1/scripts/myscript.sh
./dir1/scripts/myscript.py
./dir2

How to calculate Date difference in Hive

If you need the difference in seconds (i.e.: you're comparing dates with timestamps, and not whole days), you can simply convert two date or timestamp strings in the format 'YYYY-MM-DD HH:MM:SS' (or specify your string date format explicitly) using unix_timestamp(), and then subtract them from each other to get the difference in seconds. (And can then divide by 60.0 to get minutes, or by 3600.0 to get hours, etc.)

Example:

UNIX_TIMESTAMP('2017-12-05 10:01:30') - UNIX_TIMESTAMP('2017-12-05 10:00:00') AS time_diff -- This will return 90 (seconds). Unix_timestamp converts string dates into BIGINTs. 

More on what you can do with unix_timestamp() here, including how to convert strings with different date formatting: https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF#LanguageManualUDF-DateFunctions

How to picture "for" loop in block representation of algorithm

The Algorithm for given flow chart :

enter image description here

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Step :01

  • Start

Step :02 [Variable initialization]

  • Set counter: i<----K [Where K:Positive Number]

Step :03[Condition Check]

  • If condition True then Do your task, set i=i+N and go to Step :03 [Where N:Positive Number]
  • If condition False then go to Step :04

Step:04

  • Stop

Error CS1705: "which has a higher version than referenced assembly"

for SharePoint, make sure that under your root folder you don't have a "bin" folder with your DLL's, if so just delete it. (and change "Copy Local" to false in VS).

"Strict Standards: Only variables should be passed by reference" error

array_shift the only parameter is an array passed by reference. The return value of explode(".", $value) does not have any reference. Hence the error.

You should store the return value to a variable first.

    $arr = explode(".", $value);
    $extension = strtolower(array_pop($arr));   
    $fileName = array_shift($arr);

From PHP.net

The following things can be passed by reference:

- Variables, i.e. foo($a)
- New statements, i.e. foo(new foobar())
- [References returned from functions][2]

No other expressions should be passed by reference, as the result is undefined. For example, the following examples of passing by reference are invalid:

Get page title with Selenium WebDriver using Java

You can do it easily by using JUnit or TestNG framework. Do the assertion as below:

String actualTitle = driver.getTitle();
String expectedTitle = "Title of Page";
assertEquals(expectedTitle,actualTitle);

OR,

assertTrue(driver.getTitle().contains("Title of Page"));

How to write UPDATE SQL with Table alias in SQL Server 2008?

You can always take the CTE, (Common Tabular Expression), approach.

;WITH updateCTE AS
(
    SELECT ID, TITLE 
    FROM HOLD_TABLE
    WHERE ID = 101
)

UPDATE updateCTE
SET TITLE = 'TEST';

How to merge remote master to local branch

git rebase didn't seem to work for me. After git rebase, when I try to push changes to my local branch, I kept getting an error ("hint: Updates were rejected because the tip of your current branch is behind its remote counterpart. Integrate the remote changes (e.g. 'git pull ...') before pushing again.") even after git pull. What finally worked for me was git merge.

git checkout <local_branch>
git merge <master> 

If you are a beginner like me, here is a good article on git merge vs git rebase. https://www.atlassian.com/git/tutorials/merging-vs-rebasing

Center Plot title in ggplot2

If you are working a lot with graphs and ggplot, you might be tired to add the theme() each time. If you don't want to change the default theme as suggested earlier, you may find easier to create your own personal theme.

personal_theme = theme(plot.title = 
element_text(hjust = 0.5))

Say you have multiple graphs, p1, p2 and p3, just add personal_theme to them.

p1 + personal_theme
p2 + personal_theme
p3 + personal_theme

dat <- data.frame(
  time = factor(c("Lunch","Dinner"), 
levels=c("Lunch","Dinner")),
  total_bill = c(14.89, 17.23)
)
p1 = ggplot(data=dat, aes(x=time, y=total_bill, 
fill=time)) + 
  geom_bar(colour="black", fill="#DD8888", 
width=.8, stat="identity") + 
  guides(fill=FALSE) +
  xlab("Time of day") + ylab("Total bill") +
  ggtitle("Average bill for 2 people")

p1 + personal_theme

Byte[] to ASCII

Encoding.ASCII.GetString(buf);

How to prune local tracking branches that do not exist on remote anymore

Based on the answers above I'm using this shorter one liner:

git remote prune origin | awk 'BEGIN{FS="origin/"};/pruned/{print $2}' | xargs -r git branch -d

Also, if you already pruned and have local dangling branches, then this will clean them up:

git branch -vv | awk '/^ .*gone/{print $1}' | xargs -r git branch -d

IntelliJ and Tomcat.. Howto..?

In Netbeans you can right click on the project and run it, but in IntelliJ IDEA you have to select the index.jsp file or the welcome file to run the project.

this is because Netbeans generate the following tag in web.xml and IntelliJ do not.

<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

Code for a simple JavaScript countdown timer?

Here is another one if anyone needs one for minutes and seconds:

    var mins = 10;  //Set the number of minutes you need
    var secs = mins * 60;
    var currentSeconds = 0;
    var currentMinutes = 0;
    /* 
     * The following line has been commented out due to a suggestion left in the comments. The line below it has not been tested. 
     * setTimeout('Decrement()',1000);
     */
    setTimeout(Decrement,1000); 

    function Decrement() {
        currentMinutes = Math.floor(secs / 60);
        currentSeconds = secs % 60;
        if(currentSeconds <= 9) currentSeconds = "0" + currentSeconds;
        secs--;
        document.getElementById("timerText").innerHTML = currentMinutes + ":" + currentSeconds; //Set the element id you need the time put into.
        if(secs !== -1) setTimeout('Decrement()',1000);
    }

Xcode swift am/pm time to 24 hour format

Swift 3

Time format 24 hours to 12 hours

let dateAsString = "13:15"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm"

let date = dateFormatter.date(from: dateAsString)
dateFormatter.dateFormat = "h:mm a"
let Date12 = dateFormatter.string(from: date!)
print("12 hour formatted Date:",Date12)

output will be 12 hour formatted Date: 1:15 PM

Time format 12 hours to 24 hours

let dateAsString = "1:15 PM"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "h:mm a"

let date = dateFormatter.date(from: dateAsString)
dateFormatter.dateFormat = "HH:mm"

let Date24 = dateFormatter.string(from: date!)
print("24 hour formatted Date:",Date24)

output will be 24 hour formatted Date: 13:15

Access PHP variable in JavaScript

You can't, you'll have to do something like

<script type="text/javascript">
   var php_var = "<?php echo $php_var; ?>";
</script>

You can also load it with AJAX

rhino is right, the snippet lacks of a type for the sake of brevity.

Also, note that if $php_var has quotes, it will break your script. You shall use addslashes, htmlentities or a custom function.

How to set selectedIndex of select element using display text?

Try this:

function SelectAnimal()
{
    var animals = document.getElementById('Animals');
    var animalsToFind = document.getElementById('AnimalToFind');
    // get the options length
    var len = animals.options.length;
    for(i = 0; i < len; i++)
    {
      // check the current option's text if it's the same with the input box
      if (animals.options[i].innerHTML == animalsToFind.value)
      {
         animals.selectedIndex = i;
         break;
      }     
    }
}

Removing single-quote from a string in php

$test = "{'employees':[{'firstName':'John', 'lastName':'Doe'},{'firstName':'John', 'lastName':'Doe'}]}" ; 
$test = str_replace("'", '"', $test);
echo   $test;
$jtest = json_decode($test,true);
var_dump($jtest);

I cannot access tomcat admin console?

Notice that the http code response status you are getting is an HTTP 404. The 404 or Not Found error message is a response code indicating that the client was able to communicate with a given server, but the server could not find what was requested.

If you have got an 403 Forbidden vs 401 Unauthorized HTTP responses then it might make a sense to review your tomcat-users.xml.

Resuming: check the manager resources and files of your server installation, some file/directory might be missing, or the path to the manager resources has been changed.

How to get memory usage at runtime using C++?

in additional to your way
you could call system ps command and get memory usage from it output.
or read info from /proc/pid ( see PIOCPSINFO struct )

Why use double indirection? or Why use pointers to pointers?

For example, you might want to make sure that when you free the memory of something you set the pointer to null afterwards.

void safeFree(void** memory) {
    if (*memory) {
        free(*memory);
        *memory = NULL;
    }
}

When you call this function you'd call it with the address of a pointer

void* myMemory = someCrazyFunctionThatAllocatesMemory();
safeFree(&myMemory);

Now myMemory is set to NULL and any attempt to reuse it will be very obviously wrong.

How to redirect from one URL to another URL?

location.href = "Pagename.html";

How to override and extend basic Django admin templates?

As for Django 1.8 being the current release, there is no need to symlink, copy the admin/templates to your project folder, or install middlewares as suggested by the answers above. Here is what to do:

  1. create the following tree structure(recommended by the official documentation)

    your_project
         |-- your_project/
         |-- myapp/
         |-- templates/
              |-- admin/
                  |-- myapp/
                      |-- change_form.html  <- do not misspell this
    

Note: The location of this file is not important. You can put it inside your app and it will still work. As long as its location can be discovered by django. What's more important is the name of the HTML file has to be the same as the original HTML file name provided by django.

  1. Add this template path to your settings.py:

    TEMPLATES = [
        {
            'BACKEND': 'django.template.backends.django.DjangoTemplates',
            'DIRS': [os.path.join(BASE_DIR, 'templates')], # <- add this line
            'APP_DIRS': True,
            'OPTIONS': {
                'context_processors': [
                    'django.template.context_processors.debug',
                    'django.template.context_processors.request',
                    'django.contrib.auth.context_processors.auth',
                    'django.contrib.messages.context_processors.messages',
                ],
            },
        },
    ]
    
  2. Identify the name and block you want to override. This is done by looking into django's admin/templates directory. I am using virtualenv, so for me, the path is here:

    ~/.virtualenvs/edge/lib/python2.7/site-packages/django/contrib/admin/templates/admin
    

In this example, I want to modify the add new user form. The template responsiblve for this view is change_form.html. Open up the change_form.html and find the {% block %} that you want to extend.

  1. In your change_form.html, write somethings like this:

    {% extends "admin/change_form.html" %}
    {% block field_sets %}
         {# your modification here #}
    {% endblock %}
    
  2. Load up your page and you should see the changes

How to solve npm error "npm ERR! code ELIFECYCLE"

My solution:

I was missing config.env properties because I was developing on a new machine, and of course I keep my config files out of my repo.

If you are using a different machine than usual, make sure that you include any config files that are not present in the repo that gets cloned.

foreach vs someList.ForEach(){}

Behind the scenes, the anonymous delegate gets turned into an actual method so you could have some overhead with the second choice if the compiler didn't choose to inline the function. Additionally, any local variables referenced by the body of the anonymous delegate example would change in nature because of compiler tricks to hide the fact that it gets compiled to a new method. More info here on how C# does this magic:

http://blogs.msdn.com/oldnewthing/archive/2006/08/04/688527.aspx

Check that a variable is a number in UNIX shell

if echo $var | egrep -q '^[0-9]+$'; then
    # $var is a number
else
    # $var is not a number
fi

How do you enable auto-complete functionality in Visual Studio C++ express edition?

All the answers were missing Ctrl-J (which enables and disables autocomplete).

QByteArray to QString

Use QString::fromUtf16((ushort *)Data.data()), as shown in the following code example:

#include <QCoreApplication>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    // QByteArray to QString
    // =====================

    const char c_test[10] = {'t', '\0', 'e', '\0', 's', '\0', 't', '\0', '\0', '\0'};
    QByteArray qba_test(QByteArray::fromRawData(c_test, 10));
    qDebug().nospace().noquote() << "qba_test[" << qba_test << "]"; // Should see: qba_test[t

    QString qstr_test = QString::fromUtf16((ushort *)qba_test.data());
    qDebug().nospace().noquote() << "qstr_test[" << qstr_test << "]"; // Should see: qstr_test[test]

    return a.exec();
}

This is an alternative solution to the one using QTextCodec. The code has been tested using Qt 5.4.

How to delete all instances of a character in a string in python?

# s1 == source string
# char == find this character
# repl == replace with this character
def findreplace(s1, char, repl):
    s1 = s1.replace(char, repl)
    return s1

# find each 'i' in the string and replace with a 'u'
print findreplace('it is icy', 'i', 'u')
# output
''' ut us ucy '''

Pandas rename column by position?

try this

df.rename(columns={ df.columns[1]: "your value" }, inplace = True)

How to use CMAKE_INSTALL_PREFIX

That should be (see the docs):

cmake -DCMAKE_INSTALL_PREFIX=/usr ..

How to encrypt and decrypt file in Android?

I had a similar problem and for encrypt/decrypt i came up with this solution:

public static byte[] generateKey(String password) throws Exception
{
    byte[] keyStart = password.getBytes("UTF-8");

    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
    sr.setSeed(keyStart);
    kgen.init(128, sr);
    SecretKey skey = kgen.generateKey();
    return skey.getEncoded();
}

public static byte[] encodeFile(byte[] key, byte[] fileData) throws Exception
{

    SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
    byte[] encrypted = cipher.doFinal(fileData);

    return encrypted;
}

public static byte[] decodeFile(byte[] key, byte[] fileData) throws Exception
{
    SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);

    byte[] decrypted = cipher.doFinal(fileData);

    return decrypted;
}

To save a encrypted file to sd do:

File file = new File(Environment.getExternalStorageDirectory() + File.separator + "your_folder_on_sd", "file_name");
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
byte[] yourKey = generateKey("password");
byte[] filesBytes = encodeFile(yourKey, yourByteArrayContainigDataToEncrypt);
bos.write(fileBytes);
bos.flush();
bos.close();

To decode a file use:

byte[] yourKey = generateKey("password");
byte[] decodedData = decodeFile(yourKey, bytesOfYourFile);

For reading in a file to a byte Array there a different way out there. A Example: http://examples.javacodegeeks.com/core-java/io/fileinputstream/read-file-in-byte-array-with-fileinputstream/

How to show the last queries executed on MySQL?

Maybe you could find that out by looking at the query log.

Get the string value from List<String> through loop for display

public static void main(String[] args) {

    List<String> ls=new ArrayList<String>();
    ls.add("1");
    ls.add("2");
    ls.add("3");
    ls.add("4");

//Then  you can use "foreache" loop to iterate.

    for(String item:ls){
        System.out.println(item);
    }

}

Group by in LINQ

var results = from p in persons
              group p by p.PersonID into g
              select new { PersonID = g.Key,
                           /**/car = g.Select(g=>g.car).FirstOrDefault()/**/}

Disable / Check for Mock Location (prevent gps spoofing)

try this code its very simple and usefull

  public boolean isMockLocationEnabled() {
        boolean isMockLocation = false;
        try {
            //if marshmallow
            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                AppOpsManager opsManager = (AppOpsManager) getApplicationContext().getSystemService(Context.APP_OPS_SERVICE);
                isMockLocation = (opsManager.checkOp(AppOpsManager.OPSTR_MOCK_LOCATION, android.os.Process.myUid(), BuildConfig.APPLICATION_ID)== AppOpsManager.MODE_ALLOWED);
            } else {
                // in marshmallow this will always return true
                isMockLocation = !android.provider.Settings.Secure.getString(getApplicationContext().getContentResolver(), "mock_location").equals("0");
            }
        } catch (Exception e) {
            return isMockLocation;
        }
        return isMockLocation;
    }

Get OS-level system information

It is still under development but you can already use jHardware

It is a simple library that scraps system data using Java. It works in both Linux and Windows.

ProcessorInfo info = HardwareInfo.getProcessorInfo();
//Get named info
System.out.println("Cache size: " + info.getCacheSize());        
System.out.println("Family: " + info.getFamily());
System.out.println("Speed (Mhz): " + info.getMhz());
//[...]

NumPy array initialization (fill with identical values)

NumPy 1.8 introduced np.full(), which is a more direct method than empty() followed by fill() for creating an array filled with a certain value:

>>> np.full((3, 5), 7)
array([[ 7.,  7.,  7.,  7.,  7.],
       [ 7.,  7.,  7.,  7.,  7.],
       [ 7.,  7.,  7.,  7.,  7.]])

>>> np.full((3, 5), 7, dtype=int)
array([[7, 7, 7, 7, 7],
       [7, 7, 7, 7, 7],
       [7, 7, 7, 7, 7]])

This is arguably the way of creating an array filled with certain values, because it explicitly describes what is being achieved (and it can in principle be very efficient since it performs a very specific task).

How do I import CSV file into a MySQL table?

The mysql command line is prone to too many problems on import. Here is how you do it:

  • use excel to edit the header names to have no spaces
  • save as .csv
  • use free Navicat Lite Sql Browser to import and auto create a new table (give it a name)
  • open the new table insert a primary auto number column for ID
  • change the type of the columns as desired.
  • done!

How to disable Compatibility View in IE

The answer given by FelixFett worked for me. To reiterate:

<meta http-equiv="X-UA-Compatible" content="IE=11; IE=10; IE=9; IE=8; IE=7; IE=EDGE" />

I have it as the first 'meta' tag in my code. I added 10 and 11 as those are versions that are published now for Internet Explorer.

I would've just commented on his answer but I do not have a high enough reputation...

ImportError: No module named PIL

instead of PIL use Pillow it works

easy_install Pillow

or

pip install Pillow

Combine multiple Collections into a single logical Collection?

Plain Java 8 solutions using a Stream.

Constant number

Assuming private Collection<T> c, c2, c3.

One solution:

public Stream<T> stream() {
    return Stream.concat(Stream.concat(c.stream(), c2.stream()), c3.stream());
}

Another solution:

public Stream<T> stream() {
    return Stream.of(c, c2, c3).flatMap(Collection::stream);
}

Variable number

Assuming private Collection<Collection<T>> cs:

public Stream<T> stream() {
    return cs.stream().flatMap(Collection::stream);
}

Asp.net - Add blank item at top of dropdownlist

ddlCategory.DataSource = ds;
ddlCategory.DataTextField = "CatName";
ddlCategory.DataValueField = "CatID";

Cách 1:

ddlCategory.Items.Add(new ListItem("--please select--", "-1"));
ddlCategory.AppendDataBoundItems = true;
ddlCategory.SelectedIndex = -1;

ddlCategory.DataBind();

Cách 2:

ddlCategory.Items.Insert(0, new ListItem("-- please select --", "0"));

(Tested OK)

How do I declare a 2d array in C++ using new?

The purpose of this answer is not to add anything new that the others don't already cover, but to extend @Kevin Loney's answer.

You could use the lightweight declaration:

int *ary = new int[SizeX*SizeY]

and access syntax will be:

ary[i*SizeY+j]     // ary[i][j]

but this is cumbersome for most, and can lead to confusion. So, you can define a macro as follows:

#define ary(i, j)   ary[(i)*SizeY + (j)]

Now you can access the array using the very similar syntax ary(i, j) // means ary[i][j]. This has the advantages of being simple and beautiful, and at the same time, using expressions in place of the indices is also simpler and less confusing.

To access, say, ary[2+5][3+8], you can write ary(2+5, 3+8) instead of the complex-looking ary[(2+5)*SizeY + (3+8)] i.e. it saves parentheses and helps readability.

Caveats:

  • Although the syntax is very similar, it is NOT the same.
  • In case you pass the array to other functions, SizeY has to be passed with the same name (or instead be declared as a global variable).

Or, if you need to use the array in multiple functions, then you could add SizeY also as another parameter in the macro definition like so:

#define ary(i, j, SizeY)  ary[(i)*(SizeY)+(j)]

You get the idea. Of course, this becomes too long to be useful, but it can still prevent the confusion of + and *.

This is not recommended definitely, and it will be condemned as bad practice by most experienced users, but I couldn't resist sharing it because of its elegance.

Edit:
If you want a portable solution that works for any number of arrays, you can use this syntax:

#define access(ar, i, j, SizeY) ar[(i)*(SizeY)+(j)]

and then you can pass on any array to the call, with any size using the access syntax:

access(ary, i, j, SizeY)      // ary[i][j]

P.S.: I've tested these, and the same syntax works (as both an lvalue and an rvalue) on g++14 and g++11 compilers.

inline conditionals in angular.js

Angular UI library has built-in directive ui-if for condition in template/Views upto angular ui 1.1.4

Example: Support in Angular UI upto ui 1.1.4

<div ui-if="array.length>0"></div>

ng-if available in all the angular version after 1.1.4

<div ng-if="array.length>0"></div>

if you have any data in array variable then only the div will appear

SQLite equivalent to ISNULL(), NVL(), IFNULL() or COALESCE()

Use IS NULL or IS NOT NULL in WHERE-clause instead of ISNULL() method:

SELECT myField1
FROM myTable1
WHERE myField1 IS NOT NULL

<button> vs. <input type="button" />. Which to use?

I just want to add something to the rest of the answers here. Input elements are considered empty or void elements (other empty elements are area , base , br , col , hr , img , input , link , meta , and param. You can also check here), meaning they cannot have any content. In addition to not having any content, empty elements cannot have any pseudo-elements like ::after and ::before, which I consider a major drawback.

sh: react-scripts: command not found after running npm start

if anyone is willing to use npm only, then run this npm i react-native-scripts --save, then npm start or whatever the command you use

How to check heap usage of a running JVM from the command line?

For Java 8 you can use the following command line to get the heap space utilization in kB:

jstat -gc <PID> | tail -n 1 | awk '{split($0,a," "); sum=a[3]+a[4]+a[6]+a[8]; print sum}'

The command basically sums up:

  • S0U: Survivor space 0 utilization (kB).
  • S1U: Survivor space 1 utilization (kB).
  • EU: Eden space utilization (kB).
  • OU: Old space utilization (kB).

You may also want to include the metaspace and the compressed class space utilization. In this case you have to add a[10] and a[12] to the awk sum.

What does "javascript:void(0)" mean?

Web Developers use javascript:void(0) because it is the easiest way to prevent the default behavior of a tag. void(*anything*) returns undefined and it is a falsy value. and returning a falsy value is like return false in onclick event of a tag that prevents its default behavior.

So I think javascript:void(0) is the simplest way to prevent the default behavior of a tag.

How do I test axios in Jest?

I could do that following the steps:

  1. Create a folder __mocks__/ (as pointed by @Januartha comment)
  2. Implement an axios.js mock file
  3. Use my implemented module on test

The mock will happen automatically

Example of the mock module:

module.exports = {
    get: jest.fn((url) => {
        if (url === '/something') {
            return Promise.resolve({
                data: 'data'
            });
        }
    }),
    post: jest.fn((url) => {
        if (url === '/something') {
            return Promise.resolve({
                data: 'data'
            });
        }
        if (url === '/something2') {
            return Promise.resolve({
                data: 'data2'
            });
        }
    }),
    create: jest.fn(function () {
        return this;
    })
};

Automatic vertical scroll bar in WPF TextBlock?

<ScrollViewer Height="239" VerticalScrollBarVisibility="Auto">
    <TextBox AcceptsReturn="True" TextWrapping="Wrap" LineHeight="10" />
</ScrollViewer>

This is way to use the scrolling TextBox in XAML and use it as a text area.

What does PHP keyword 'var' do?

var is used like public .if a varable is declared like this in a class var $a; if means its scope is public for the class. in simplea words var ~public

var $a;
public

docker: Error response from daemon: Get https://registry-1.docker.io/v2/: Service Unavailable. IN DOCKER , MAC

I had this same issue when working on an Ubuntu server.

I was getting the following error:

deploy@my-comp:~$ docker login -u my-username -p my-password
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp 35.175.83.85:443: connect: connection refused

Here are the things I tried that did not work:

  • Restarting the docker service using sudo docker systemctl restart docker
  • Powering off and restarting the Ubuntu server.
  • Changing the name server to 8.8.8.8 in the /etc/resolv.conf file

Here's what worked for me:

I tried checking if the server has access to the internet using the following netcat command:

nc -vz google.com 443

And it returned this output:

nc: connect to google.com port 443 (tcp) failed: Connection refused
nc: connect to google.com port 443 (tcp) failed: Network is unreachable

Instead of something like this:

Ncat: Version 7.70 ( https://nmap.org/ncat )
Ncat: Connected to 172.217.166.110:443.
Ncat: 0 bytes sent, 0 bytes received in 0.07 seconds.

I tried checking again if the server has access to the internet using the following wget command:

wget -q --spider http://google.com ; echo $?

And it returned:

4

Instead of:

0

Note: Anything other than 0 in the output means your system is not connected to the internet

I then tried the last time if the server has access to the internet using the following Nmap command:

nmap -p 443 google.com

And it returned:

Starting Nmap 7.01 ( https://nmap.org ) at 2021-02-16 11:50 WAT
Nmap scan report for google.com (216.58.223.238)
Host is up (0.00052s latency).
Other addresses for google.com (not scanned): 2c0f:fb50:4003:802::200e
rDNS record for 216.58.223.238: los02s04-in-f14.1e100.net
PORT    STATE  SERVICE
443/tcp closed https

Nmap done: 1 IP address (1 host up) scanned in 1.21 seconds

Instead something like this:

Starting Nmap 7.01 ( https://nmap.org ) at 2021-02-16 11:50 WAT
Nmap scan report for google.com (216.58.223.238)
Host is up (0.00052s latency).
Other addresses for google.com (not scanned): 2c0f:fb50:4003:802::200e
rDNS record for 216.58.223.238: los02s04-in-f14.1e100.net
PORT    STATE  SERVICE
443/tcp open https

Nmap done: 1 IP address (1 host up) scanned in 1.21 seconds

Note: The state of port 443/tcp is closed instead of open

All this was enough to make me realize that connections to the internet were not allowed on the server.

All I had to do was speak with the team in charge of infrastructure to fix the network connectivity issue to the internet on the server. And once that was fixed my docker command started working fine.

Resources: 9 commands to check if connected to internet with shell script examples

That's all.

I hope this helps

Iterate through a C++ Vector using a 'for' loop

If you use

std::vector<std::reference_wrapper<std::string>> names{ };

Do not forget, when you use auto in the for loop, to use also get, like this:

for (auto element in : names)
{
    element.get()//do something
}

Present and dismiss modal view controller

The easiest way i tired in xcode 4.52 was to create an additional view and connect them by using segue modal(control drag the button from view one to the second view, chose Modal). Then drag in a button to second view or the modal view that you created. Control and drag this button to the header file and use action connection. This will create an IBaction in your controller.m file. Find your button action type in the code.

[self dismissViewControllerAnimated:YES completion:nil];

Reading a resource file from within jar

The problem is that certain third party libraries require file pathnames rather than input streams. Most of the answers don't address this issue.

In this case, one workaround is to copy the resource contents into a temporary file. The following example uses jUnit's TemporaryFolder.

    private List<String> decomposePath(String path){
        List<String> reversed = Lists.newArrayList();
        File currFile = new File(path);
        while(currFile != null){
            reversed.add(currFile.getName());
            currFile = currFile.getParentFile();
        }
        return Lists.reverse(reversed);
    }

    private String writeResourceToFile(String resourceName) throws IOException {
        ClassLoader loader = getClass().getClassLoader();
        InputStream configStream = loader.getResourceAsStream(resourceName);
        List<String> pathComponents = decomposePath(resourceName);
        folder.newFolder(pathComponents.subList(0, pathComponents.size() - 1).toArray(new String[0]));
        File tmpFile = folder.newFile(resourceName);
        Files.copy(configStream, tmpFile.toPath(), REPLACE_EXISTING);
        return tmpFile.getAbsolutePath();
    }

How do I add an active class to a Link from React Router?

Its very easy to do that, react-router-dom provides all.

_x000D_
_x000D_
import React from 'react';_x000D_
import { matchPath, withRouter } from 'react-router';_x000D_
    _x000D_
class NavBar extends React.Component {_x000D_
  render(){_x000D_
    return(_x000D_
       <ul className="sidebar-menu">_x000D_
      <li className="header">MAIN NAVIGATION</li>_x000D_
      <li className={matchPath(this.props.location.pathname, { path: "/dashboard" }) ? 'active' : ''}><Link to="dashboard"><i className="fa fa-dashboard"></i> _x000D_
        <span>Dashboard</span></Link></li>_x000D_
      <li className={matchPath(this.props.location.pathname, { path: "/email_lists" }) ? 'active' : ''}><Link to="email_lists"><i className="fa fa-envelope-o"></i> _x000D_
        <span>Email Lists</span></Link></li>_x000D_
      <li className={matchPath(this.props.location.pathname, { path: "/billing" }) ? 'active' : ''}><Link to="billing"><i className="fa fa-credit-card"></i> _x000D_
        <span>Buy Verifications</span></Link></li>_x000D_
    </ul>_x000D_
      )_x000D_
   }_x000D_
}_x000D_
    _x000D_
export default withRouter(NavBar);
_x000D_
_x000D_
_x000D_

Wrapping You Navigation Component with withRouter() HOC will provide few props to your component: 1. match 2. history 3. location

here i used matchPath() method from react-router to compare the paths and decide if the 'li' tag should get "active" class name or not. and Im accessing the location from this.props.location.pathname.

changing the path name in props will happen when our link is clicked, and location props will get updated NavBar also get re-rendered and active style will get applied

github markdown colspan

There is no way to do so. Either use an HTML table, or put the same text on several cells.

like this:

| Can Reorder | 2nd operation |2nd operation |2nd operation |
| :---: | --- |
|1st operation|Normal Load <br/>Normal Store| Volatile Load <br/>MonitorEnter|Volatile Store<br/> MonitorExit|
|Normal Load <br/> Normal Store| | | No|
|Volatile Load <br/> MonitorEnter| No|No|No|
|Volatile store <br/> MonitorExit| | No|No|

which looks like

HTML table

Laravel 5.2 Missing required parameters for [Route: user.profile] [URI: user/{nickname}/profile]

You have to pass the route parameters to the route method, for example:

<li><a href="{{ route('user.profile', $nickname) }}">Profile</a></li>
<li><a href="{{ route('user.settings', $nickname) }}">Settings</a></li>

It's because, both routes have a {nickname} in the route declaration. I've used $nickname for example but make sure you change the $nickname to appropriate value/variable, for example, it could be something like the following:

<li><a href="{{ route('user.settings', auth()->user()->nickname) }}">Settings</a></li>

use mysql SUM() in a WHERE clause

In general, a condition in the WHERE clause of an SQL query can reference only a single row. The context of a WHERE clause is evaluated before any order has been defined by an ORDER BY clause, and there is no implicit order to an RDBMS table.

You can use a derived table to join each row to the group of rows with a lesser id value, and produce the sum of each sum group. Then test where the sum meets your criterion.

CREATE TABLE MyTable ( id INT PRIMARY KEY, cash INT );

INSERT INTO MyTable (id, cash) VALUES
  (1, 200), (2, 301), (3, 101), (4, 700);

SELECT s.*
FROM (
  SELECT t.id, SUM(prev.cash) AS cash_sum
  FROM MyTable t JOIN MyTable prev ON (t.id > prev.id)
  GROUP BY t.id) AS s
WHERE s.cash_sum >= 500
ORDER BY s.id
LIMIT 1;

Output:

+----+----------+
| id | cash_sum |
+----+----------+
|  3 |      501 |
+----+----------+

Create hive table using "as select" or "like" and also specify delimiter

Both the answers provided above work fine.

  1. CREATE TABLE person AS select * from employee;
  2. CREATE TABLE person LIKE employee;

javac error: Class names are only accepted if annotation processing is explicitly requested

i think this is also because of incorrect compilation..

so for linux (ubuntu).....

javac file.java

java file

Replace comma with newline in sed on MacOS?

Apparently \r is the key!

$ sed 's/, /\r/g' file3.txt > file4.txt

Transformed this:

ABFS, AIRM, AMED, BOSC, CALI, ECPG, FRGI, GERN, GTIV, HSON, IQNT, JRCC, LTRE,
MACK, MIDD, NKTR, NPSP, PME, PTIX, REFR, RSOL, UBNT, UPI, YONG, ZEUS

To this:

ABFS
AIRM
AMED
BOSC
CALI
ECPG
FRGI
GERN
GTIV
HSON
IQNT
JRCC
LTRE
MACK
MIDD
NKTR
NPSP
PME
PTIX
REFR
RSOL
UBNT
UPI
YONG
ZEUS

How do I correct "Commit Failed. File xxx is out of date. xxx path not found."

I just had this problem, and the cause seemed to be that a directory had been flagged as in conflict. To fix:

svn update
svn resolved <the directory in conflict>
svn commit

SQL: Group by minimum value in one field while selecting distinct rows

I would like to add to some of the other answers here, if you don't need the first item but say the second number for example you can use rownumber in a subquery and base your result set off of that.

SELECT * FROM
(
    SELECT
        ROW_NUM() OVER (PARTITION BY Id ORDER BY record_date, other_cols) as rownum,
        *
    FROM products P
) INNER
WHERE rownum = 2

This also allows you to order off multiple columns in the subquery which may help if two record_dates have identical values. You can also partition off of multiple columns if needed by delimiting them with a comma

Get the value of bootstrap Datetimepicker in JavaScript

I'm using the latest Bootstrap 3 DateTime Picker (http://eonasdan.github.io/bootstrap-datetimepicker/)

This is how you should use DateTime Picker inline:

var selectedDate = $("#datetimepicker").find(".active").data("day");

The above returned: 03/23/2017

Lodash - difference between .extend() / .assign() and .merge()

If you want a deep copy without override while retaining the same obj reference

obj = _.assign(obj, _.merge(obj, [source]))

Why are empty catch blocks a bad idea?

Empty catch blocks are usually put in because the coder doesn't really know what they are doing. At my organization, an empty catch block must include a comment as to why doing nothing with the exception is a good idea.

On a related note, most people don't know that a try{} block can be followed with either a catch{} or a finally{}, only one is required.

Opacity of div's background without affecting contained element in IE 8?

it's simple only you have do is to give

background: rgba(0,0,0,0.3)

& for IE use this filter

background: transparent;
zoom: 1;    
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#4C000000,endColorstr=#4C000000); /* IE 6 & 7 */
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#4C000000,endColorstr=#4C000000)"; /* IE8 */

you can generate your rgba filter from here http://kimili.com/journal/rgba-hsla-css-generator-for-internet-explorer/

What is 0x10 in decimal?

Notice that '10' is the representation of the base in that base:

10 is 2(decimal) in base-2

10 is 3(decimal) in base-3

...

10 is 10(decimal) in base-10

...

10 is 16(decimal) in base-16 (hexadecimal)

...

10 is 1024(decimal) in base-1024

...and so on

git rm - fatal: pathspec did not match any files

git stash 

did the job, It restored the files that I had deleted using rm instead of git rm.

I did first a checkout of the last hash, but I do not believe it is required.

How to read specific lines from a file (by line number)?

file = '/path/to/file_to_be_read.txt'
with open(file) as f:
    print f.readlines()[26]
    print f.readlines()[30]

Using the with statement, this opens the file, prints lines 26 and 30, then closes the file. Simple!

How do I get current scope dom-element in AngularJS controller?

In controller:

function innerItem($scope, $element){
    var jQueryInnerItem = $($element); 
}

how to write value into cell with vba code without auto type conversion?

Cells(1,1).Value2 = "'123,456"

note the single apostrophe before the number - this will signal to excel that whatever follows has to be interpreted as text.

Find Item in ObservableCollection without using a loop

You're looking for a hash based collection (like a Dictionary or Hashset) which the ObservableCollection is not. The best solution might be to derive from a hash based collection and implement INotifyCollectionChanged which will give you the same behavior as an ObservableCollection.

How to clear a notification in Android

I believe the most RECENT and UPDATED for AndroidX and backward compatibility. The best way of doing (Kotlin and Java) this should be done as:

NotificationManagerCompat.from(context).cancel(NOTIFICATION_ID)

Or to cancel all notifications is:

NotificationManagerCompat.from(context).cancelAll()

Made for AndroidX or Support Libraries.

maxReceivedMessageSize and maxBufferSize in app.config

Open app.config on client side and add maxBufferSize and maxReceivedMessageSize attributes if it is not available

Original

  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="Service1Soap"/>
      </basicHttpBinding>
    </bindings>

After Edit/Update

  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="Service1Soap" maxBufferSize="2147483647" maxReceivedMessageSize="2147483647"/>
      </basicHttpBinding>
    </bindings>

How to check if a number is a power of 2

in this approach , you can check if there is only 1 set bit in the integer and the integer is > 0 (c++).

bool is_pow_of_2(int n){
    int count = 0;
    for(int i = 0; i < 32; i++){
        count += (n>>i & 1);
    }
    return count == 1 && n > 0;
}

iOS 7: UITableView shows under status bar

I don't know how Kosher it is, but I found that this scheme moves the ViewController's view down and provides the status bar with a solid background:

- (void)viewDidLoad {
    [super viewDidLoad];

    // Shove everything down if iOS 7 or later
    float systemVersion = [[[UIDevice currentDevice] systemVersion] floatValue];
    if (systemVersion >= 7.0f) {

        // Move the view down 20 pixels
        CGRect bounds = self.view.bounds;
        bounds.origin.y -= 20.0;
        [self.view setBounds:bounds];

        // Create a solid color background for the status bar
        CGRect statusFrame = CGRectMake(0.0, -20.0, bounds.size.width, 20);
        UIView* statusBar = [[UIView alloc] initWithFrame:statusFrame];
        statusBar.backgroundColor = [UIColor redColor];
        [self.view addSubview:statusBar];
    }

Of course, replace redColor with whatever color you want for the background.

You must separately do one of the swizzles to set the color of the characters/symbols in the status bar. I use View controller-based status bar appearance = NO and Status bar style = Opaque black style in the plist, to do this globally.

Seems to work, and I'd be interested to hear of any bugs or issues with it.

Prevent PDF file from downloading and printing

Okay, I take back what I commented earlier. Just talked to one of the senior guys in my shop and he said it is possible to lock it down hard. What you can do is convert the pdf to an image/flash/whatever and wrap it in an iFrame. Then, you create another image with 100% transparency and lay it over top the iFrame (not in it) and set it to have a higher Z-value than the iFrame.

What this will do is that if they right click on the 'image' to save it, they will be saving the transparent image instead. And since the image 'overrides' the iFrame, any attempt to use print screen should be shielded by the image, and they should only be able to snapshot the image that doesn't actually exist.

That leaves only one or two ways to get at the file...which requires digging straight into the source code to find the image file inside the iFrame. Still not totally secure, but protected from your average user.

Confirm deletion in modal / dialog using Twitter Bootstrap?

When its comes to a relevantly big project we may need something re-usable. This is something I came with with help of SO.

confirmDelete.jsp

<!-- Modal Dialog -->
<div class="modal fade" id="confirmDelete" role="dialog" aria-labelledby="confirmDeleteLabel"
 aria-hidden="true">
<div class="modal-dialog">
    <div class="modal-content">
        <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal"
                    aria-hidden="true">&times;</button>
            <h4 class="modal-title">Delete Parmanently</h4>
        </div>
        <div class="modal-body" style="height: 75px">
            <p>Are you sure about this ?</p>
        </div>
        <div class="modal-footer">
            <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
            <button type="button" class="btn btn-danger" id="confirm-delete-ok">Ok
            </button>
        </div>
    </div>
</div>

<script type="text/javascript">

    var url_for_deletion = "#";
    var success_redirect = window.location.href;

$('#confirmDelete').on('show.bs.modal', function (e) {
    var message = $(e.relatedTarget).attr('data-message');
    $(this).find('.modal-body p').text(message);
    var title = $(e.relatedTarget).attr('data-title');
    $(this).find('.modal-title').text(title);

    if (typeof  $(e.relatedTarget).attr('data-url') != 'undefined') {
        url_for_deletion = $(e.relatedTarget).attr('data-url');
    }
    if (typeof  $(e.relatedTarget).attr('data-success-url') != 'undefined') {
        success_redirect = $(e.relatedTarget).attr('data-success-url');
    }

});

<!-- Form confirm (yes/ok) handler, submits form -->
$('#confirmDelete').find('.modal-footer #confirm-delete-ok').on('click', function () {
    $.ajax({
        method: "delete",
        url: url_for_deletion,
    }).success(function (data) {
        window.location.href = success_redirect;
    }).fail(function (error) {
        console.log(error);
    });
    $('#confirmDelete').modal('hide');
    return false;
});
<script/>

reusingPage.jsp

<a href="#" class="table-link danger"
data-toggle="modal"
data-target="#confirmDelete"
data-title="Delete Something"
data-message="Are you sure you want to inactivate this something?"
data-url="client/32"
id="delete-client-32">
</a>
<!-- jQuery should come before this -->
<%@ include file="../some/path/confirmDelete.jsp" %>

Note: This uses http delete method for delete request, you can change it from javascript or, can send it using a data-attribute as in data-title or data-url etc, for support any request.

navigator.geolocation.getCurrentPosition sometimes works sometimes doesn't

I noticed this problem recently myself, and I'm not sure how it comes about but it would appear sometimes firefox gets stuck on something loaded in cache. After clearing cache and restarting firefox it appears to function again.

How can I extract the folder path from file path in Python?

WITH PATHLIB MODULE (UPDATED ANSWER)

One should consider using pathlib for new development. It is in the stdlib for Python3.4, but available on PyPI for earlier versions. This library provides a more object-orented method to manipulate paths <opinion> and is much easier read and program with </opinion>.

>>> import pathlib
>>> existGDBPath = pathlib.Path(r'T:\Data\DBDesign\DBDesign_93_v141b.mdb')
>>> wkspFldr = existGDBPath.parent
>>> print wkspFldr
Path('T:\Data\DBDesign')

WITH OS MODULE

Use the os.path module:

>>> import os
>>> existGDBPath = r'T:\Data\DBDesign\DBDesign_93_v141b.mdb'
>>> wkspFldr = os.path.dirname(existGDBPath)
>>> print wkspFldr 
'T:\Data\DBDesign'

You can go ahead and assume that if you need to do some sort of filename manipulation it's already been implemented in os.path. If not, you'll still probably need to use this module as the building block.

What is the "hasClass" function with plain JavaScript?

This 'hasClass' function works in IE8+, FireFox and Chrome:

hasClass = function(el, cls) {
    var regexp = new RegExp('(\\s|^)' + cls + '(\\s|$)'),
        target = (typeof el.className === 'undefined') ? window.event.srcElement : el;
    return target.className.match(regexp);
}

[Updated Jan'2021] A better way:

hasClass = (el, cls) => {
  [...el.classList].includes(cls); //cls without dot
};

Python wildcard search in string

Easy method is try os.system:

import os
text = 'this is text'
os.system("echo %s | grep 't*'" % text)

Enable & Disable a Div and its elements in Javascript

The following selects all descendant elements and disables them:

$("#dcacl").find("*").prop("disabled", true);

But it only really makes sense to disable certain element types: inputs, buttons, etc., so you want a more specific selector:

$("#dcac1").find(":input").prop("disabled",true);
// noting that ":input" gives you the equivalent of
$("#dcac1").find("input,select,textarea,button").prop("disabled",true);

To re-enable you just set "disabled" to false.

I want to Disable them at loading the page and then by a click i can enable them

OK, so put the above code in a document ready handler, and setup an appropriate click handler:

$(document).ready(function() {
    var $dcac1kids = $("#dcac1").find(":input");
    $dcac1kids.prop("disabled",true);

    // not sure what you want to click on to re-enable
    $("selector for whatever you want to click").one("click",function() {
       $dcac1kids.prop("disabled",false);
    }
}

I've cached the results of the selector on the assumption that you're not adding more elements to the div between the page load and the click. And I've attached the click handler with .one() since you haven't specified a requirement to re-disable the elements so presumably the event only needs to be handled once. Of course you can change the .one() to .click() if appropriate.

Passing data between different controller action methods

If you need to pass data from one controller to another you must pass data by route values.Because both are different request.if you send data from one page to another then you have to user query string(same as route values).

But you can do one trick :

In your calling action call the called action as a simple method :

public class ServerController : Controller
{
 [HttpPost]
 public ActionResult ApplicationPoolsUpdate(ServiceViewModel viewModel)
 {
      XDocument updatedResultsDocument = myService.UpdateApplicationPools();
      ApplicationPoolController pool=new ApplicationPoolController(); //make an object of ApplicationPoolController class.

      return pool.UpdateConfirmation(updatedResultsDocument); // call the ActionMethod you want as a simple method and pass the model as an argument.
      // Redirect to ApplicationPool controller and pass
      // updatedResultsDocument to be used in UpdateConfirmation action method
 }
}

What is the difference between --save and --save-dev?

By default, NPM simply installs a package under node_modules. When you're trying to install dependencies for your app/module, you would need to first install them, and then add them to the dependencies section of your package.json.

--save-dev adds the third-party package to the package's development dependencies. It won't be installed when someone runs npm install directly to install your package. It's typically only installed if someone clones your source repository first and then runs npm install in it.

--save adds the third-party package to the package's dependencies. It will be installed together with the package whenever someone runs npm install package.

Dev dependencies are those dependencies that are only needed for developing the package. That can include test runners, compilers, packagers, etc. Both types of dependencies are stored in the package's package.json file. --save adds to dependencies, --save-dev adds to devDependencies

npm install documentation can be referred here.

--

Please note that --save is now the default option, since NPM 5. Therefore, it is not explicitly needed anymore. It is possible to run npm install without the --save to achieve the same result.

ln (Natural Log) in Python

math.log is the natural logarithm:

From the documentation:

math.log(x[, base]) With one argument, return the natural logarithm of x (to base e).

Your equation is therefore:

n = math.log((1 + (FV * r) / p) / math.log(1 + r)))

Note that in your code you convert n to a str twice which is unnecessary

Warn user before leaving web page with unsaved changes

Following code works great. You need to reach your form elements' input changes via id attribute:

var somethingChanged=false;
            $('#managerForm input').change(function() { 
                somethingChanged = true; 
           }); 
            $(window).bind('beforeunload', function(e){
                if(somethingChanged)
                    return "You made some changes and it's not saved?";
                else 
                    e=null; // i.e; if form state change show warning box, else don't show it.
            });
        });

PHP how to get value from array if key is in a variable

$value = ( array_key_exists($key, $array) && !empty($array[$key]) ) 
         ? $array[$key] 
         : 'non-existant or empty value key';

How to set a single, main title above all the subplots with Pyplot?

Use pyplot.suptitle or Figure.suptitle:

import matplotlib.pyplot as plt
import numpy as np

fig=plt.figure()
data=np.arange(900).reshape((30,30))
for i in range(1,5):
    ax=fig.add_subplot(2,2,i)        
    ax.imshow(data)

fig.suptitle('Main title') # or plt.suptitle('Main title')
plt.show()

enter image description here

How to check if android checkbox is checked within its onClick method (declared in XML)?

try this one :

public void itemClicked(View v) {
  //code to check if this checkbox is checked!
  CheckBox checkBox = (CheckBox)v;
  if(checkBox.isChecked()){

  }
}

Check whether a table contains rows or not sql server 2005

FOR the best performance, use specific column name instead of * - for example:

SELECT TOP 1 <columnName> 
FROM <tableName> 

This is optimal because, instead of returning the whole list of columns, it is returning just one. That can save some time.

Also, returning just first row if there are any values, makes it even faster. Actually you got just one value as the result - if there are any rows, or no value if there is no rows.

If you use the table in distributed manner, which is most probably the case, than transporting just one value from the server to the client is much faster.

You also should choose wisely among all the columns to get data from a column which can take as less resource as possible.

Rendering HTML elements to <canvas>

RasterizeHTML is a very good project, but if you need to access the canvas it wont work on chrome. due to the use of <foreignObject>.

If you need to access the canvas then you can use html2canvas

I am trying to find another project as html2canvas is very slow in performance

Gradients in Internet Explorer 9

The code I use for all browser gradients:

background: #0A284B;
background: -webkit-gradient(linear, left top, left bottom, from(#0A284B), to(#135887));
background: -webkit-linear-gradient(#0A284B, #135887);
background: -moz-linear-gradient(top, #0A284B, #135887);
background: -ms-linear-gradient(#0A284B, #135887);
background: -o-linear-gradient(#0A284B, #135887);
background: linear-gradient(#0A284B, #135887);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#0A284B', endColorstr='#135887');
zoom: 1;

You will need to specify a height or zoom: 1 to apply hasLayout to the element for this to work in IE.


Update:

Here is a LESS Mixin (CSS) version for all you LESS users out there:

.gradient(@start, @end) {
    background: mix(@start, @end, 50%);
    filter: ~"progid:DXImageTransform.Microsoft.gradient(startColorStr="@start~", EndColorStr="@end~")";
    background: -webkit-gradient(linear, left top, left bottom, from(@start), to(@end));
    background: -webkit-linear-gradient(@start, @end);
    background: -moz-linear-gradient(top, @start, @end);
    background: -ms-linear-gradient(@start, @end);
    background: -o-linear-gradient(@start, @end);
    background: linear-gradient(@start, @end);
    zoom: 1;
}

Proxy Error 502 : The proxy server received an invalid response from an upstream server

The java application takes too long to respond(maybe due start-up/jvm being cold) thus you get the proxy error.

Proxy Error

The proxy server received an invalid response from an upstream server.
 The proxy server could not handle the request GET /lin/Campaignn.jsp.

As Albert Maclang said amending the http timeout configuration may fix the issue. I suspect the java application throws a 500+ error thus the apache gateway error too. You should look in the logs.

How do you increase the max number of concurrent connections in Apache?

Here's a detailed explanation about the calculation of MaxClients and MaxRequestsPerChild

http://web.archive.org/web/20160415001028/http://www.genericarticles.com/mediawiki/index.php?title=How_to_optimize_apache_web_server_for_maximum_concurrent_connections_or_increase_max_clients_in_apache

ServerLimit 16
StartServers 2
MaxClients 200
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25

First of all, whenever an apache is started, it will start 2 child processes which is determined by StartServers parameter. Then each process will start 25 threads determined by ThreadsPerChild parameter so this means 2 process can service only 50 concurrent connections/clients i.e. 25x2=50. Now if more concurrent users comes, then another child process will start, that can service another 25 users. But how many child processes can be started is controlled by ServerLimit parameter, this means that in the configuration above, I can have 16 child processes in total, with each child process can handle 25 thread, in total handling 16x25=400 concurrent users. But if number defined in MaxClients is less which is 200 here, then this means that after 8 child processes, no extra process will start since we have defined an upper cap of MaxClients. This also means that if I set MaxClients to 1000, after 16 child processes and 400 connections, no extra process will start and we cannot service more than 400 concurrent clients even if we have increase the MaxClient parameter. In this case, we need to also increase ServerLimit to 1000/25 i.e. MaxClients/ThreadsPerChild=40 So this is the optmized configuration to server 1000 clients

<IfModule mpm_worker_module>
    ServerLimit          40
    StartServers          2
    MaxClients          1000
    MinSpareThreads      25
    MaxSpareThreads      75 
    ThreadsPerChild      25
    MaxRequestsPerChild   0
</IfModule>

Python: Fetch first 10 results from a list

Use the slicing operator:

list = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
list[:10]

Fastest way to list all primes below N

This is the way you can compare with others.

# You have to list primes upto n
nums = xrange(2, n)
for i in range(2, 10):
    nums = filter(lambda s: s==i or s%i, nums)
print nums

So simple...

Get filename from input [type='file'] using jQuery

There is no jQuery function for this. You have to access the DOM element and check the files property.

document.getElementById("image_file").files[0];

Or

$('#image_file')[0].files[0]

When is the finalize() method called in Java?

The finalize method is called when an object is about to get garbage collected. That can be at any time after it has become eligible for garbage collection.

Note that it's entirely possible that an object never gets garbage collected (and thus finalize is never called). This can happen when the object never becomes eligible for gc (because it's reachable through the entire lifetime of the JVM) or when no garbage collection actually runs between the time the object become eligible and the time the JVM stops running (this often occurs with simple test programs).

There are ways to tell the JVM to run finalize on objects that it wasn't called on yet, but using them isn't a good idea either (the guarantees of that method aren't very strong either).

If you rely on finalize for the correct operation of your application, then you're doing something wrong. finalize should only be used for cleanup of (usually non-Java) resources. And that's exactly because the JVM doesn't guarantee that finalize is ever called on any object.

How do I check form validity with angularjs?

You can also use myform.$invalid

E.g.

if($scope.myform.$invalid){return;}

Changing :hover to touch/click for mobile devices

You can add onclick="" to hovered element. Hover will work after that.

Edit: But you really shouldn't add anything style related to your markup, just posted it as an alternative.

Negative regex for Perl string pattern match

Sample text:

Clinton said
Bush used crayons
Reagan forgot

Just omitting a Bush match:

$ perl -ne 'print if /^(Clinton|Reagan)/' textfile
Clinton said
Reagan forgot

Or if you really want to specify:

$ perl -ne 'print if /^(?!Bush)(Clinton|Reagan)/' textfile
Clinton said
Reagan forgot

INSERT statement conflicted with the FOREIGN KEY constraint - SQL Server

Something I found was that all the fields have to match EXACTLY.

For example, sending 'cat dog' is not the same as sending 'catdog'.

What I did to troubleshoot this was to script out the FK code from the table I was inserting data into, take note of the "Foreign Key" that had the constraints (in my case there were 2) and make sure those 2 fields values matched EXACTLY as they were in the table that was throwing the FK Constraint error.

Once I fixed the 2 fields giving my problems, life was good!

If you need a better explanation, let me know.

Django REST Framework: adding additional field to ModelSerializer

With the last version of Django Rest Framework, you need to create a method in your model with the name of the field you want to add. No need for @property and source='field' raise an error.

class Foo(models.Model):
    . . .
    def foo(self):
        return 'stuff'
    . . .

class FooSerializer(ModelSerializer):
    foo = serializers.ReadOnlyField()

    class Meta:
        model = Foo
        fields = ('foo',)

How to validate a credit card number

These are my two cents.

Note #1: this is not a perfect validation method, but it is OK for my needs.
Note #2: IIN ranges can be changed (and will be), so it is a good idea to check this link to be sure that we are up to date.

function validateCCNum(ccnum)
{
    var ccCheckRegExp = /[^\d\s-]/;
    var isValid = !ccCheckRegExp.test(ccnum);
    var i;

    if (isValid) {
        var cardNumbersOnly = ccnum.replace(/[\s-]/g,"");
        var cardNumberLength = cardNumbersOnly.length;

        var arrCheckTypes = ['visa', 'mastercard', 'amex', 'discover', 'dinners', 'jcb'];
        for(i=0; i<arrCheckTypes.length; i++) {
            var lengthIsValid = false;
            var prefixIsValid = false;
            var prefixRegExp;

            switch (arrCheckTypes[i]) {
                case "mastercard":
                    lengthIsValid = (cardNumberLength === 16);
                    prefixRegExp = /5[1-5][0-9]|(2(?:2[2-9][^0]|2[3-9]|[3-6]|22[1-9]|7[0-1]|72[0]))\d*/;
                    break;

                case "visa":
                    lengthIsValid = (cardNumberLength === 16 || cardNumberLength === 13);
                    prefixRegExp = /^4/;
                    break;

                case "amex":
                    lengthIsValid = (cardNumberLength === 15);
                    prefixRegExp = /^3([47])/;
                    break;

                case "discover":
                    lengthIsValid = (cardNumberLength === 15 || cardNumberLength === 16);
                    prefixRegExp = /^(6011|5)/;
                    break;

                case "dinners":
                    lengthIsValid = (cardNumberLength === 14);
                    prefixRegExp = /^(300|301|302|303|304|305|36|38)/;
                    break;

                case "jcb":
                    lengthIsValid = (cardNumberLength === 15 || cardNumberLength === 16);
                    prefixRegExp = /^(2131|1800|35)/;
                    break;

                default:
                    prefixRegExp = /^$/;
            }

            prefixIsValid = prefixRegExp.test(cardNumbersOnly);
            isValid = prefixIsValid && lengthIsValid;

            // Check if we found a correct one
            if(isValid) {
                break;
            }
        }
    }

    if (!isValid) {
        return false;
    }

    // Remove all dashes for the checksum checks to eliminate negative numbers
    ccnum = ccnum.replace(/[\s-]/g,"");
    // Checksum ("Mod 10")
    // Add even digits in even length strings or odd digits in odd length strings.
    var checksum = 0;
    for (i = (2 - (ccnum.length % 2)); i <= ccnum.length; i += 2) {
        checksum += parseInt(ccnum.charAt(i - 1));
    }

    // Analyze odd digits in even length strings or even digits in odd length strings.
    for (i = (ccnum.length % 2) + 1; i < ccnum.length; i += 2) {
        var digit = parseInt(ccnum.charAt(i - 1)) * 2;
        if (digit < 10) {
            checksum += digit;
        } else {
            checksum += (digit - 9);
        }
    }

    return (checksum % 10) === 0;
}

Thanks to @Peter Mortensen for the comment :)

What's the difference between utf8_general_ci and utf8_unicode_ci?

For those people still arriving at this question in 2020 or later, there are newer options that may be better than both of these. For example, utf8mb4_0900_ai_ci.

All these collations are for the UTF-8 character encoding. The differences are in how text is sorted and compared.

_unicode_ci and _general_ci are two different sets of rules for sorting and comparing text according to the way we expect. Newer versions of MySQL introduce new sets of rules, too, such as _0900_ai_ci for equivalent rules based on Unicode 9.0 - and with no equivalent _general_ci variant. People reading this now should probably use one of these newer collations instead of either _unicode_ci or _general_ci. The description of those older collations below is provided for interest only.

MySQL is currently transitioning away from an older, flawed UTF-8 implementation. For now, you need to use utf8mb4 instead of utf8 for the character encoding part, to ensure you are getting the fixed version. The flawed version remains for backward compatibility, though it is being deprecated.

Key differences

  • utf8mb4_unicode_ci is based on the official Unicode rules for universal sorting and comparison, which sorts accurately in a wide range of languages.

  • utf8mb4_general_ci is a simplified set of sorting rules which aims to do as well as it can while taking many short-cuts designed to improve speed. It does not follow the Unicode rules and will result in undesirable sorting or comparison in some situations, such as when using particular languages or characters.

    On modern servers, this performance boost will be all but negligible. It was devised in a time when servers had a tiny fraction of the CPU performance of today's computers.

Benefits of utf8mb4_unicode_ci over utf8mb4_general_ci

utf8mb4_unicode_ci, which uses the Unicode rules for sorting and comparison, employs a fairly complex algorithm for correct sorting in a wide range of languages and when using a wide range of special characters. These rules need to take into account language-specific conventions; not everybody sorts their characters in what we would call 'alphabetical order'.

As far as Latin (ie "European") languages go, there is not much difference between the Unicode sorting and the simplified utf8mb4_general_ci sorting in MySQL, but there are still a few differences:

  • For examples, the Unicode collation sorts "ß" like "ss", and "Œ" like "OE" as people using those characters would normally want, whereas utf8mb4_general_ci sorts them as single characters (presumably like "s" and "e" respectively).

  • Some Unicode characters are defined as ignorable, which means they shouldn't count toward the sort order and the comparison should move on to the next character instead. utf8mb4_unicode_ci handles these properly.

In non-latin languages, such as Asian languages or languages with different alphabets, there may be a lot more differences between Unicode sorting and the simplified utf8mb4_general_ci sorting. The suitability of utf8mb4_general_ci will depend heavily on the language used. For some languages, it'll be quite inadequate.

What should you use?

There is almost certainly no reason to use utf8mb4_general_ci anymore, as we have left behind the point where CPU speed is low enough that the performance difference would be important. Your database will almost certainly be limited by other bottlenecks than this.

In the past, some people recommended to use utf8mb4_general_ci except when accurate sorting was going to be important enough to justify the performance cost. Today, that performance cost has all but disappeared, and developers are treating internationalization more seriously.

There's an argument to be made that if speed is more important to you than accuracy, you may as well not do any sorting at all. It's trivial to make an algorithm faster if you do not need it to be accurate. So, utf8mb4_general_ci is a compromise that's probably not needed for speed reasons and probably also not suitable for accuracy reasons.

One other thing I'll add is that even if you know your application only supports the English language, it may still need to deal with people's names, which can often contain characters used in other languages in which it is just as important to sort correctly. Using the Unicode rules for everything helps add peace of mind that the very smart Unicode people have worked very hard to make sorting work properly.

What the parts mean

Firstly, ci is for case-insensitive sorting and comparison. This means it's suitable for textual data, and case is not important. The other types of collation are cs (case-sensitive) for textual data where case is important, and bin, for where the encoding needs to match, bit for bit, which is suitable for fields which are really encoded binary data (including, for example, Base64). Case-sensitive sorting leads to some weird results and case-sensitive comparison can result in duplicate values differing only in letter case, so case-sensitive collations are falling out of favor for textual data - if case is significant to you, then otherwise ignorable punctuation and so on is probably also significant, and a binary collation might be more appropriate.

Next, unicode or general refers to the specific sorting and comparison rules - in particular, the way text is normalized or compared. There are many different sets of rules for the utf8mb4 character encoding, with unicode and general being two that attempt to work well in all possible languages rather than one specific one. The differences between these two sets of rules are the subject of this answer. Note that unicode uses rules from Unicode 4.0. Recent versions of MySQL add the rulesets unicode_520 using rules from Unicode 5.2, and 0900 (dropping the "unicode_" part) using rules from Unicode 9.0.

And lastly, utf8mb4 is of course the character encoding used internally. In this answer I'm talking only about Unicode based encodings.

AWS : The config profile (MyName) could not be found

I think there is something missing from the AWS documentation in http://docs.aws.amazon.com/lambda/latest/dg/setup-awscli.html, it did not mention that you should edit the file ~/.aws/config to add your username profile. There are two ways to do this:

  1. edit ~/.aws/config or

  2. aws configure --profile "your username"

How can I change the size of a Bootstrap checkbox?

It is possible in css, but not for all the browsers.

The effect on all browsers:

http://www.456bereastreet.com/lab/form_controls/checkboxes/

A possibility is a custom checkbox with javascript:

http://ryanfait.com/resources/custom-checkboxes-and-radio-buttons/

Bootstrap 3.0 Popovers and tooltips

I use this on all my pages to enable tooltip

$(function () { $("[data-toggle='tooltip']").tooltip(); });

Pandas sort by group aggregate and column

Groupby A:

In [0]: grp = df.groupby('A')

Within each group, sum over B and broadcast the values using transform. Then sort by B:

In [1]: grp[['B']].transform(sum).sort('B')
Out[1]:
          B
2 -2.829710
5 -2.829710
1  0.253651
4  0.253651
0  0.551377
3  0.551377

Index the original df by passing the index from above. This will re-order the A values by the aggregate sum of the B values:

In [2]: sort1 = df.ix[grp[['B']].transform(sum).sort('B').index]

In [3]: sort1
Out[3]:
     A         B      C
2  baz -0.528172  False
5  baz -2.301539   True
1  bar -0.611756   True
4  bar  0.865408  False
0  foo  1.624345  False
3  foo -1.072969   True

Finally, sort the 'C' values within groups of 'A' using the sort=False option to preserve the A sort order from step 1:

In [4]: f = lambda x: x.sort('C', ascending=False)

In [5]: sort2 = sort1.groupby('A', sort=False).apply(f)

In [6]: sort2
Out[6]:
         A         B      C
A
baz 5  baz -2.301539   True
    2  baz -0.528172  False
bar 1  bar -0.611756   True
    4  bar  0.865408  False
foo 3  foo -1.072969   True
    0  foo  1.624345  False

Clean up the df index by using reset_index with drop=True:

In [7]: sort2.reset_index(0, drop=True)
Out[7]:
     A         B      C
5  baz -2.301539   True
2  baz -0.528172  False
1  bar -0.611756   True
4  bar  0.865408  False
3  foo -1.072969   True
0  foo  1.624345  False

How do I fire an event when a iframe has finished loading in jQuery?

I had to show a loader while pdf in iFrame is loading so what i come up with:

    loader({href:'loader.gif', onComplete: function(){
            $('#pd').html('<iframe onLoad="loader.close();" src="pdf" width="720px" height="600px" >Please wait... your report is loading..</iframe>');
    }
    });

I'm showing a loader. Once I'm sure that customer can see my loader, i'm calling onCompllet loaders method that loads an iframe. Iframe has an "onLoad" event. Once PDF is loaded it triggers onloat event where i'm hiding the loader :)

The important part:

iFrame has "onLoad" event where you can do what you need (hide loaders etc.)

React Native Responsive Font Size

Need to use this way I have used this one and it's working fine.

react-native-responsive-screen npm install react-native-responsive-screen --save

Just like I have a device 1080x1920

The vertical number we calculate from height **hp**
height:200
200/1920*100 = 10.41% - height:hp("10.41%")


The Horizontal number we calculate from width **wp**
width:200
200/1080*100 = 18.51% - Width:wp("18.51%")

It's working for all device

Using Java with Nvidia GPUs (CUDA)

First of all, you should be aware of the fact that CUDA will not automagically make computations faster. On the one hand, because GPU programming is an art, and it can be very, very challenging to get it right. On the other hand, because GPUs are well-suited only for certain kinds of computations.

This may sound confusing, because you can basically compute anything on the GPU. The key point is, of course, whether you will achieve a good speedup or not. The most important classification here is whether a problem is task parallel or data parallel. The first one refers, roughly speaking, to problems where several threads are working on their own tasks, more or less independently. The second one refers to problems where many threads are all doing the same - but on different parts of the data.

The latter is the kind of problem that GPUs are good at: They have many cores, and all the cores do the same, but operate on different parts of the input data.

You mentioned that you have "simple math but with huge amount of data". Although this may sound like a perfectly data-parallel problem and thus like it was well-suited for a GPU, there is another aspect to consider: GPUs are ridiculously fast in terms of theoretical computational power (FLOPS, Floating Point Operations Per Second). But they are often throttled down by the memory bandwidth.

This leads to another classification of problems. Namely whether problems are memory bound or compute bound.

The first one refers to problems where the number of instructions that are done for each data element is low. For example, consider a parallel vector addition: You'll have to read two data elements, then perform a single addition, and then write the sum into the result vector. You will not see a speedup when doing this on the GPU, because the single addition does not compensate for the efforts of reading/writing the memory.

The second term, "compute bound", refers to problems where the number of instructions is high compared to the number of memory reads/writes. For example, consider a matrix multiplication: The number of instructions will be O(n^3) when n is the size of the matrix. In this case, one can expect that the GPU will outperform a CPU at a certain matrix size. Another example could be when many complex trigonometric computations (sine/cosine etc) are performed on "few" data elements.

As a rule of thumb: You can assume that reading/writing one data element from the "main" GPU memory has a latency of about 500 instructions....

Therefore, another key point for the performance of GPUs is data locality: If you have to read or write data (and in most cases, you will have to ;-)), then you should make sure that the data is kept as close as possible to the GPU cores. GPUs thus have certain memory areas (referred to as "local memory" or "shared memory") that usually is only a few KB in size, but particularly efficient for data that is about to be involved in a computation.

So to emphasize this again: GPU programming is an art, that is only remotely related to parallel programming on the CPU. Things like Threads in Java, with all the concurrency infrastructure like ThreadPoolExecutors, ForkJoinPools etc. might give the impression that you just have to split your work somehow and distribute it among several processors. On the GPU, you may encounter challenges on a much lower level: Occupancy, register pressure, shared memory pressure, memory coalescing ... just to name a few.

However, when you have a data-parallel, compute-bound problem to solve, the GPU is the way to go.


A general remark: Your specifically asked for CUDA. But I'd strongly recommend you to also have a look at OpenCL. It has several advantages. First of all, it's an vendor-independent, open industry standard, and there are implementations of OpenCL by AMD, Apple, Intel and NVIDIA. Additionally, there is a much broader support for OpenCL in the Java world. The only case where I'd rather settle for CUDA is when you want to use the CUDA runtime libraries, like CUFFT for FFT or CUBLAS for BLAS (Matrix/Vector operations). Although there are approaches for providing similar libraries for OpenCL, they can not directly be used from Java side, unless you create your own JNI bindings for these libraries.


You might also find it interesting to hear that in October 2012, the OpenJDK HotSpot group started the project "Sumatra": http://openjdk.java.net/projects/sumatra/ . The goal of this project is to provide GPU support directly in the JVM, with support from the JIT. The current status and first results can be seen in their mailing list at http://mail.openjdk.java.net/mailman/listinfo/sumatra-dev


However, a while ago, I collected some resources related to "Java on the GPU" in general. I'll summarize these again here, in no particular order.

(Disclaimer: I'm the author of http://jcuda.org/ and http://jocl.org/ )

(Byte)code translation and OpenCL code generation:

https://github.com/aparapi/aparapi : An open-source library that is created and actively maintained by AMD. In a special "Kernel" class, one can override a specific method which should be executed in parallel. The byte code of this method is loaded at runtime using an own bytecode reader. The code is translated into OpenCL code, which is then compiled using the OpenCL compiler. The result can then be executed on the OpenCL device, which may be a GPU or a CPU. If the compilation into OpenCL is not possible (or no OpenCL is available), the code will still be executed in parallel, using a Thread Pool.

https://github.com/pcpratts/rootbeer1 : An open-source library for converting parts of Java into CUDA programs. It offers dedicated interfaces that may be implemented to indicate that a certain class should be executed on the GPU. In contrast to Aparapi, it tries to automatically serialize the "relevant" data (that is, the complete relevant part of the object graph!) into a representation that is suitable for the GPU.

https://code.google.com/archive/p/java-gpu/ : A library for translating annotated Java code (with some limitations) into CUDA code, which is then compiled into a library that executes the code on the GPU. The Library was developed in the context of a PhD thesis, which contains profound background information about the translation process.

https://github.com/ochafik/ScalaCL : Scala bindings for OpenCL. Allows special Scala collections to be processed in parallel with OpenCL. The functions that are called on the elements of the collections can be usual Scala functions (with some limitations) which are then translated into OpenCL kernels.

Language extensions

http://www.ateji.com/px/index.html : A language extension for Java that allows parallel constructs (e.g. parallel for loops, OpenMP style) which are then executed on the GPU with OpenCL. Unfortunately, this very promising project is no longer maintained.

http://www.habanero.rice.edu/Publications.html (JCUDA) : A library that can translate special Java Code (called JCUDA code) into Java- and CUDA-C code, which can then be compiled and executed on the GPU. However, the library does not seem to be publicly available.

https://www2.informatik.uni-erlangen.de/EN/research/JavaOpenMP/index.html : Java language extension for for OpenMP constructs, with a CUDA backend

Java OpenCL/CUDA binding libraries

https://github.com/ochafik/JavaCL : Java bindings for OpenCL: An object-oriented OpenCL library, based on auto-generated low-level bindings

http://jogamp.org/jocl/www/ : Java bindings for OpenCL: An object-oriented OpenCL library, based on auto-generated low-level bindings

http://www.lwjgl.org/ : Java bindings for OpenCL: Auto-generated low-level bindings and object-oriented convenience classes

http://jocl.org/ : Java bindings for OpenCL: Low-level bindings that are a 1:1 mapping of the original OpenCL API

http://jcuda.org/ : Java bindings for CUDA: Low-level bindings that are a 1:1 mapping of the original CUDA API

Miscellaneous

http://sourceforge.net/projects/jopencl/ : Java bindings for OpenCL. Seem to be no longer maintained since 2010

http://www.hoopoe-cloud.com/ : Java bindings for CUDA. Seem to be no longer maintained


Is it possible to Turn page programmatically in UIPageViewController?

Swift 4:

I needed to go to the next controller when i tap next on a pagecontroller view controller and also update the pageControl index, so this was the best and most straightforward solution for me:

let pageController = self.parent as! PageViewController

pageController.setViewControllers([parentVC.orderedViewControllers[1]], direction: .forward, animated: true, completion: nil)

pageController.pageControl.currentPage = 1

How to send POST request?

If you don't want to use a module you have to install like requests, and your use case is very basic, then you can use urllib2

urllib2.urlopen(url, body)

See the documentation for urllib2 here: https://docs.python.org/2/library/urllib2.html.

What is the difference between Numpy's array() and asarray() functions?

The difference can be demonstrated by this example:

  1. generate a matrix

    >>> A = numpy.matrix(numpy.ones((3,3)))
    >>> A
    matrix([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])
    
  2. use numpy.array to modify A. Doesn't work because you are modifying a copy

    >>> numpy.array(A)[2]=2
    >>> A
    matrix([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 1.,  1.,  1.]])
    
  3. use numpy.asarray to modify A. It worked because you are modifying A itself

    >>> numpy.asarray(A)[2]=2
    >>> A
    matrix([[ 1.,  1.,  1.],
            [ 1.,  1.,  1.],
            [ 2.,  2.,  2.]])
    

Hope this helps!

'was not declared in this scope' error

The scope of a variable is always the block it is inside. For example if you do something like

if(...)
{
     int y = 5; //y is created
} //y leaves scope, since the block ends.
else
{
     int y = 8; //y is created
} //y leaves scope, since the block ends.

cout << y << endl; //Gives error since y is not defined.

The solution is to define y outside of the if blocks

int y; //y is created

if(...)
{
     y = 5;
} 
else
{
     y = 8;
} 

cout << y << endl; //Ok

In your program you have to move the definition of y and c out of the if blocks into the higher scope. Your Function then would look like this:

//Using the Gaussian algorithm
int dayofweek(int date, int month, int year )
{
    int y, c;
    int d=date;

    if (month==1||month==2)
    {
         y=((year-1)%100);
         c=(year-1)/100;
    }
    else
    {
         y=year%100;
         c=year/100;
    }
int m=(month+9)%12+1;
int product=(d+(2.6*m-0.2)+y+y/4+c/4-2*c);
return product%7;
}

Regular expression: find spaces (tabs/space) but not newlines

Note: For those dealing with CJK text (Chinese, Japanese, and Korean), the double-byte space (Unicode \u3000) is not included in \s for any implementation I've tried so far (Perl, .NET, PCRE, Python). You'll need to either normalize your strings first (such as by replacing all \u3000 with \u0020), or you'll have to use a character set that includes this codepoint in addition to whatever other whitespace you're targeting, such as [ \t\u3000].

If you're using Perl or PCRE, you have the option of using the \h shorthand for horizontal whitespace, which appears to include the single-byte space, double-byte space, and tab, among others. See the Match whitespace but not newlines (Perl) thread for more detail.

However, this \h shorthand has not been implemented for .NET and C#, as best I've been able to tell.

Docker-Compose with multiple services

The thing is that you are using the option -t when running your container.

Could you check if enabling the tty option (see reference) in your docker-compose.yml file the container keeps running?

version: '2'
services:
  ubuntu:
        build: .
        container_name: ubuntu
        volumes:
            - ~/sph/laravel52:/www/laravel
        ports:
          - "80:80"
        tty: true

Forbidden You don't have permission to access /wp-login.php on this server

This should work :

The instructions says that you add a separate .htaccess containing the lines above to the wp-admin folder - and leave the main .htaccess, in the root, alone.

if that don't help , you can try this:

copy the .htaccess file as is from the wp-admin and placed it in the root folder and bingo! It should work ! if you face new error after this let us know.

for reference you can look here as well:

http://wordpress.org/support/topic/you-dont-have-permission-to-access-blogwp-loginphp-on-this-server

Check using this:

<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

How to send POST in angularjs with multiple params?

add the transformRequest as below to send multiple params to backend

var jq = jQuery.noConflict();
            var transform = function(data) {
                return jq.param(data);
            };
            var config = {
                headers: {
                'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
                },transformRequest: transform
            };

      var params={
            blogPostJson:JSON.stringify($scope.blogPost),
            publish:$scope.blogPost.active
        };
        var url = "${createLink(controller : 'cms', action : 'saveBlog')}";
            $http.post(url,params, config).then(function onSuccess(response) {
                var data = response.data;
               // var status = response.status;
                if (data.error) {
                    alert('error :' + data.error);
                } else {
                  //  alert('Success');

                }

            }).catch(function onError(response) {
                //console.log ("Unable to save Alcohol information");
            });

How to download and save a file from Internet using Java?

There is method U.fetch(url) in underscore-java library.

pom.xml:

  <groupId>com.github.javadev</groupId>
  <artifactId>underscore</artifactId>
  <version>1.45</version>

Code example:

import com.github.underscore.lodash.U;

public class Download {
    public static void main(String ... args) {
        String text = U.fetch("https://stackoverflow.com/questions"
        + "/921262/how-to-download-and-save-a-file-from-internet-using-java").text();
    }
}