Programs & Examples On #Godi

How to set up a PostgreSQL database in Django

Please note that installation of psycopg2 via pip or setup.py requires to have Visual Studio 2008 (more precisely executable file vcvarsall.bat). If you don't have admin rights to install it or set the appropriate PATH variable on Windows, you can download already compiled library from here.

pandas: to_numeric for multiple columns

another way is using apply, one liner:

cols = ['col1', 'col2', 'col3']
data[cols] = data[cols].apply(pd.to_numeric, errors='coerce', axis=1)

Find a file in python

SARose's answer worked for me until I updated from Ubuntu 20.04 LTS. The slight change I made to his code makes it work on the latest Ubuntu release.

import subprocess

def find_files(file_name):
    command = ['locate'+ ' ' + file_name]
    output = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True).communicate()[0]
    output = output.decode()
    search_results = output.split('\n')
    return search_results

Return JSON for ResponseEntity<String>

An alternative solution is to use a wrapper for the String, for instances this:

public class StringResponse {
    private String response;
    public StringResponse(String response) {
        this.response = response;
    }
    public String getResponse() {
        return response;
    }
}

Then return this in your controller's methods:

ResponseEntity<StringResponse>

How do I generate a random int number?

The easiest way is probably just Random.range(1, 3) This would generate a number between 1 and 2.

How to establish a connection pool in JDBC?

Usually if you need a connection pool you are writing an application that runs in some managed environment, that is you are running inside an application server. If this is the case be sure to check what connection pooling facilities your application server providesbefore trying any other options.

The out-of-the box solution will be the best integrated with the rest of the application servers facilities. If however you are not running inside an application server I would recommend the Apache Commons DBCP Component. It is widely used and provides all the basic pooling functionality most applications require.

How do I compare strings in GoLang?

== is the correct operator to compare strings in Go. However, the strings that you read from STDIN with reader.ReadString do not contain "a", but "a\n" (if you look closely, you'll see the extra line break in your example output).

You can use the strings.TrimRight function to remove trailing whitespaces from your input:

if strings.TrimRight(input, "\n") == "a" {
    // ...
}

javax.naming.NameNotFoundException

I am getting the error (...) javax.naming.NameNotFoundException: greetJndi not bound

This means that nothing is bound to the jndi name greetJndi, very likely because of a deployment problem given the incredibly low quality of this tutorial (check the server logs). I'll come back on this.

Is there any specific directory structure to deploy in JBoss?

The internal structure of the ejb-jar is supposed to be like this (using the poor naming conventions and the default package as in the mentioned link):

.
+-- greetBean.java
+-- greetHome.java
+-- greetRemote.java
+-- META-INF
    +-- ejb-jar.xml
    +-- jboss.xml

But as already mentioned, this tutorial is full of mistakes:

  • there is an extra character (<enterprise-beans>] <-- HERE) in the ejb-jar.xml (!)
  • a space is missing after PUBLIC in the ejb-jar.xml and jboss.xml (!!)
  • the jboss.xml is incorrect, it should contain a session element instead of entity (!!!)

Here is a "fixed" version of the ejb-jar.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" "http://java.sun.com/dtd/ejb-jar_2_0.dtd">
<ejb-jar>
  <enterprise-beans>
    <session>
      <ejb-name>greetBean</ejb-name>
      <home>greetHome</home>
      <remote>greetRemote</remote>
      <ejb-class>greetBean</ejb-class>
      <session-type>Stateless</session-type>
      <transaction-type>Container</transaction-type>
    </session>
  </enterprise-beans>
</ejb-jar>

And of the jboss.xml:

<?xml version="1.0"?>
<!DOCTYPE jboss PUBLIC "-//JBoss//DTD JBOSS 3.2//EN" "http://www.jboss.org/j2ee/dtd/jboss_3_2.dtd">
<jboss>
  <enterprise-beans>
    <session>
      <ejb-name>greetBean</ejb-name>
      <jndi-name>greetJndi</jndi-name>
    </session>
  </enterprise-beans>
</jboss>

After doing these changes and repackaging the ejb-jar, I was able to successfully deploy it:

21:48:06,512 INFO  [Ejb3DependenciesDeployer] Encountered deployment AbstractVFSDeploymentContext@5060868{vfszip:/home/pascal/opt/jboss-5.1.0.GA/server/default/deploy/greet.jar/}
21:48:06,534 INFO  [EjbDeployer] installing bean: ejb/#greetBean,uid19981448
21:48:06,534 INFO  [EjbDeployer]   with dependencies:
21:48:06,534 INFO  [EjbDeployer]   and supplies:
21:48:06,534 INFO  [EjbDeployer]    jndi:greetJndi
21:48:06,624 INFO  [EjbModule] Deploying greetBean
21:48:06,661 WARN  [EjbModule] EJB configured to bypass security. Please verify if this is intended. Bean=greetBean Deployment=vfszip:/home/pascal/opt/jboss-5.1.0.GA/server/default/deploy/greet.jar/
21:48:06,805 INFO  [ProxyFactory] Bound EJB Home 'greetBean' to jndi 'greetJndi'

That tutorial needs significant improvement; I'd advise from staying away from roseindia.net.

How do I expand the output display to see more columns of a pandas DataFrame?

You can adjust pandas print options with set_printoptions.

In [3]: df.describe()
Out[3]: 
<class 'pandas.core.frame.DataFrame'>
Index: 8 entries, count to max
Data columns:
x1    8  non-null values
x2    8  non-null values
x3    8  non-null values
x4    8  non-null values
x5    8  non-null values
x6    8  non-null values
x7    8  non-null values
dtypes: float64(7)

In [4]: pd.set_printoptions(precision=2)

In [5]: df.describe()
Out[5]: 
            x1       x2       x3       x4       x5       x6       x7
count      8.0      8.0      8.0      8.0      8.0      8.0      8.0
mean   69024.5  69025.5  69026.5  69027.5  69028.5  69029.5  69030.5
std       17.1     17.1     17.1     17.1     17.1     17.1     17.1
min    69000.0  69001.0  69002.0  69003.0  69004.0  69005.0  69006.0
25%    69012.2  69013.2  69014.2  69015.2  69016.2  69017.2  69018.2
50%    69024.5  69025.5  69026.5  69027.5  69028.5  69029.5  69030.5
75%    69036.8  69037.8  69038.8  69039.8  69040.8  69041.8  69042.8
max    69049.0  69050.0  69051.0  69052.0  69053.0  69054.0  69055.0

However this will not work in all cases as pandas detects your console width and it will only use to_string if the output fits in the console (see the docstring of set_printoptions). In this case you can explicitly call to_string as answered by BrenBarn.

Update

With version 0.10 the way wide dataframes are printed changed:

In [3]: df.describe()
Out[3]: 
                 x1            x2            x3            x4            x5  \
count      8.000000      8.000000      8.000000      8.000000      8.000000   
mean   59832.361578  27356.711336  49317.281222  51214.837838  51254.839690   
std    22600.723536  26867.192716  28071.737509  21012.422793  33831.515761   
min    31906.695474   1648.359160     56.378115  16278.322271     43.745574   
25%    45264.625201  12799.540572  41429.628749  40374.273582  29789.643875   
50%    56340.214856  18666.456293  51995.661512  54894.562656  47667.684422   
75%    75587.003417  31375.610322  61069.190523  67811.893435  76014.884048   
max    98136.474782  84544.484627  91743.983895  75154.587156  99012.695717   

                 x6            x7  
count      8.000000      8.000000  
mean   41863.000717  33950.235126  
std    38709.468281  29075.745673  
min     3590.990740   1833.464154  
25%    15145.759625   6879.523949  
50%    22139.243042  33706.029946  
75%    72038.983496  51449.893980  
max    98601.190488  83309.051963  

Further more the API for setting pandas options changed:

In [4]: pd.set_option('display.precision', 2)

In [5]: df.describe()
Out[5]: 
            x1       x2       x3       x4       x5       x6       x7
count      8.0      8.0      8.0      8.0      8.0      8.0      8.0
mean   59832.4  27356.7  49317.3  51214.8  51254.8  41863.0  33950.2
std    22600.7  26867.2  28071.7  21012.4  33831.5  38709.5  29075.7
min    31906.7   1648.4     56.4  16278.3     43.7   3591.0   1833.5
25%    45264.6  12799.5  41429.6  40374.3  29789.6  15145.8   6879.5
50%    56340.2  18666.5  51995.7  54894.6  47667.7  22139.2  33706.0
75%    75587.0  31375.6  61069.2  67811.9  76014.9  72039.0  51449.9
max    98136.5  84544.5  91744.0  75154.6  99012.7  98601.2  83309.1

Docker container not starting (docker start)

You are trying to run bash, an interactive shell that requires a tty in order to operate. It doesn't really make sense to run this in "detached" mode with -d, but you can do this by adding -it to the command line, which ensures that the container has a valid tty associated with it and that stdin remains connected:

docker run -it -d -p 52022:22 basickarl/docker-git-test

You would more commonly run some sort of long-lived non-interactive process (like sshd, or a web server, or a database server, or a process manager like systemd or supervisor) when starting detached containers.

If you are trying to run a service like sshd, you cannot simply run service ssh start. This will -- depending on the distribution you're running inside your container -- do one of two things:

  • It will try to contact a process manager like systemd or upstart to start the service. Because there is no service manager running, this will fail.

  • It will actually start sshd, but it will be started in the background. This means that (a) the service sshd start command exits, which means that (b) Docker considers your container to have failed, so it cleans everything up.

If you want to run just ssh in a container, consider an example like this.

If you want to run sshd and other processes inside the container, you will need to investigate some sort of process supervisor.

AngularJS : The correct way of binding to a service properties

I think it's a better way to bind on the service itself instead of the attributes on it.

Here's why:

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.7/angular.min.js"></script>
<body ng-app="BindToService">

  <div ng-controller="BindToServiceCtrl as ctrl">
    ArrService.arrOne: <span ng-repeat="v in ArrService.arrOne">{{v}}</span>
    <br />
    ArrService.arrTwo: <span ng-repeat="v in ArrService.arrTwo">{{v}}</span>
    <br />
    <br />
    <!-- This is empty since $scope.arrOne never changes -->
    arrOne: <span ng-repeat="v in arrOne">{{v}}</span>
    <br />
    <!-- This is not empty since $scope.arrTwo === ArrService.arrTwo -->
    <!-- Both of them point the memory space modified by the `push` function below -->
    arrTwo: <span ng-repeat="v in arrTwo">{{v}}</span>
  </div>

  <script type="text/javascript">
    var app = angular.module("BindToService", []);

    app.controller("BindToServiceCtrl", function ($scope, ArrService) {
      $scope.ArrService = ArrService;
      $scope.arrOne = ArrService.arrOne;
      $scope.arrTwo = ArrService.arrTwo;
    });

    app.service("ArrService", function ($interval) {
      var that = this,
          i = 0;
      this.arrOne = [];
      that.arrTwo = [];

      $interval(function () {
        // This will change arrOne (the pointer).
        // However, $scope.arrOne is still same as the original arrOne.
        that.arrOne = that.arrOne.concat([i]);

        // This line changes the memory block pointed by arrTwo.
        // And arrTwo (the pointer) itself never changes.
        that.arrTwo.push(i);
        i += 1;
      }, 1000);

    });
  </script>
</body> 

You can play it on this plunker.

Parsing JSON with Unix tools

There is an easier way to get a property from a json string. Using a package.json file as an example, try this:

#!/usr/bin/env bash
my_val="$(json=$(<package.json) node -pe "JSON.parse(process.env.json)['version']")"

We're using process.env because this gets the file's contents into node.js as a string without any risk of malicious contents escaping their quoting and being parsed as code.

jQuery scroll() detect when user stops scrolling

I agreed with some of the comments above that listening for a timeout wasn't accurate enough as that will trigger when you stop moving the scroll bar for long enough instead of when you stop scrolling. I think a better solution is to listen for the user letting go of the mouse (mouseup) as soon as they start scrolling:

$(window).scroll(function(){
    $('#scrollMsg').html('SCROLLING!');
    var stopListener = $(window).mouseup(function(){ // listen to mouse up
        $('#scrollMsg').html('STOPPED SCROLLING!');
        stopListner(); // Stop listening to mouse up after heard for the first time 
    });
});

and an example of it working can be seen in this JSFiddle

What's the HTML to have a horizontal space between two objects?

Another way you can add horizontal space between elements is to set up labels to preserve spaces in css:

label {
   white-space: pre;
}

..and then add a label with as many spaces as you want:

<label>  </label>

What does the question mark in Java generics' type parameter mean?

In English:

It's a List of some type that extends the class HasWord, including HasWord

In general the ? in generics means any class. And the extends SomeClass specifies that that object must extend SomeClass (or be that class).

How to disable button in React.js

Using refs is not best practice because it reads the DOM directly, it's better to use React's state instead. Also, your button doesn't change because the component is not re-rendered and stays in its initial state.

You can use setState together with an onChange event listener to render the component again every time the input field changes:

// Input field listens to change, updates React's state and re-renders the component.
<input onChange={e => this.setState({ value: e.target.value })} value={this.state.value} />

// Button is disabled when input state is empty.
<button disabled={!this.state.value} />

Here's a working example:

_x000D_
_x000D_
class AddItem extends React.Component {_x000D_
  constructor() {_x000D_
    super();_x000D_
    this.state = { value: '' };_x000D_
    this.onChange = this.onChange.bind(this);_x000D_
    this.add = this.add.bind(this);_x000D_
  }_x000D_
_x000D_
  add() {_x000D_
    this.props.onButtonClick(this.state.value);_x000D_
    this.setState({ value: '' });_x000D_
  }_x000D_
_x000D_
  onChange(e) {_x000D_
    this.setState({ value: e.target.value });_x000D_
  }_x000D_
_x000D_
  render() {_x000D_
    return (_x000D_
      <div className="add-item">_x000D_
        <input_x000D_
          type="text"_x000D_
          className="add-item__input"_x000D_
          value={this.state.value}_x000D_
          onChange={this.onChange}_x000D_
          placeholder={this.props.placeholder}_x000D_
        />_x000D_
        <button_x000D_
          disabled={!this.state.value}_x000D_
          className="add-item__button"_x000D_
          onClick={this.add}_x000D_
        >_x000D_
          Add_x000D_
        </button>_x000D_
      </div>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
_x000D_
ReactDOM.render(_x000D_
  <AddItem placeholder="Value" onButtonClick={v => console.log(v)} />,_x000D_
  document.getElementById('View')_x000D_
);
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>_x000D_
<div id='View'></div>
_x000D_
_x000D_
_x000D_

How to remove "href" with Jquery?

Your title question and your example are completely different. I'll start by answering the title question:

$("a").removeAttr("href");

And as far as not requiring an href, the generally accepted way of doing this is:

<a href"#" onclick="doWork(); return false;">link</a>

The return false is necessary so that the href doesn't actually go anywhere.

System.loadLibrary(...) couldn't find native library in my case

For reference, I had this error message and the solution was that when you specify the library you miss the 'lib' off the front and the '.so' from the end.

So, if you have a file libmyfablib.so, you need to call:

   System.loadLibrary("myfablib"); // this loads the file 'libmyfablib.so' 

Having looked in the apk, installed/uninstalled and tried all kinds of complex solutions I couldn't see the simple problem that was right in front of my face!

What is a clean, Pythonic way to have multiple constructors in Python?

This is how I solved it for a YearQuarter class I had to create. I created an __init__ which is very tolerant to a wide variety of input.

You use it like this:

>>> from datetime import date
>>> temp1 = YearQuarter(year=2017, month=12)
>>> print temp1
2017-Q4
>>> temp2 = YearQuarter(temp1)
>>> print temp2
2017-Q4
>>> temp3 = YearQuarter((2017, 6))
>>> print temp3
2017-Q2 
>>> temp4 = YearQuarter(date(2017, 1, 18))
>>> print temp4
2017-Q1
>>> temp5 = YearQuarter(year=2017, quarter = 3)
>>> print temp5
2017-Q3

And this is how the __init__ and the rest of the class looks like:

import datetime


class YearQuarter:

    def __init__(self, *args, **kwargs):
        if len(args) == 1:
            [x]     = args

            if isinstance(x, datetime.date):
                self._year      = int(x.year)
                self._quarter   = (int(x.month) + 2) / 3
            elif isinstance(x, tuple):
                year, month     = x

                self._year      = int(year)

                month           = int(month)

                if 1 <= month <= 12:
                    self._quarter   = (month + 2) / 3
                else:
                    raise ValueError

            elif isinstance(x, YearQuarter):
                self._year      = x._year
                self._quarter   = x._quarter

        elif len(args) == 2:
            year, month     = args

            self._year      = int(year)

            month           = int(month)

            if 1 <= month <= 12:
                self._quarter   = (month + 2) / 3
            else:
                raise ValueError

        elif kwargs:

            self._year      = int(kwargs["year"])

            if "quarter" in kwargs:
                quarter     = int(kwargs["quarter"])

                if 1 <= quarter <= 4:
                    self._quarter     = quarter
                else:
                    raise ValueError
            elif "month" in kwargs:
                month   = int(kwargs["month"])

                if 1 <= month <= 12:
                    self._quarter     = (month + 2) / 3
                else:
                    raise ValueError

    def __str__(self):
        return '{0}-Q{1}'.format(self._year, self._quarter)

Creating a simple configuration file and parser in C++

A naive approach could look like this:

#include <map>
#include <sstream>
#include <stdexcept>
#include <string>

std::map<std::string, std::string> options; // global?

void parse(std::istream & cfgfile)
{
    for (std::string line; std::getline(cfgfile, line); )
    {
        std::istringstream iss(line);
        std::string id, eq, val;

        bool error = false;

        if (!(iss >> id))
        {
            error = true;
        }
        else if (id[0] == '#')
        {
            continue;
        }
        else if (!(iss >> eq >> val >> std::ws) || eq != "=" || iss.get() != EOF)
        {
            error = true;
        }

        if (error)
        {
            // do something appropriate: throw, skip, warn, etc.
        }
        else
        {
            options[id] = val;
        }
    }
}

Now you can access each option value from the global options map anywhere in your program. If you want castability, you could make the mapped type a boost::variant.

Convert hex string (char []) to int?

i have done a similar thing, think it might help u its actually working for me

int main(){ int co[8],i;char ch[8];printf("please enter the string:");scanf("%s",ch);for(i=0;i<=7;i++){if((ch[i]>='A')&&(ch[i]<='F')){co[i]=(unsigned int)ch[i]-'A'+10;}else if((ch[i]>='0')&&(ch[i]<='9')){co[i]=(unsigned int)ch[i]-'0'+0;}}

here i have only taken a string of 8 characters. if u want u can add similar logic for 'a' to 'f' to give their equivalent hex values,i haven't done that cause i didn't needed it.

Reset Excel to default borders

In Excel 2016 for Mac, I clicked the Excel menu, then clicked Preferences…

I then clicked the View icon.

whereupon I found a Gridlines Checkbox next to a Color Picker.

Regardless of whether the Gridlines checkbox os checked or not, if you change the color in the Color Picker dropdown menu, your cell borders will become that color. (I believe the change took place after i quit excel and opened the document the next day to continue working on it but I can't accurately remember.)

Changing the color picker back to Automatic will return your cell borders to the default (black) color on-the-fly.

N.B. Because I'm a newbie I cannot insert the screen shots I prepared ahead of time.

How to revert initial git commit?

I will throw in what worked for me in the end. I needed to remove the initial commit on a repository as quarantined data had been misplaced, the commit had already been pushed.

Make sure you are are currently on the right branch.

git checkout master

git update-ref -d HEAD

git commit -m "Initial commit

git push -u origin master

This was able to resolve the problem.

Important

This was on an internal repository which was not publicly accessible, if your repository was publicly accessible please assume anything you need to revert has already been pulled down by someone else.

Count(*) vs Count(1) - SQL Server

SET STATISTICS TIME ON

select count(1) from MyTable (nolock) -- table containing 1 million records. 

SQL Server Execution Times:
CPU time = 31 ms, elapsed time = 36 ms.

select count(*) from MyTable (nolock) -- table containing 1 million records. 

SQL Server Execution Times:
CPU time = 46 ms, elapsed time = 37 ms.

I've ran this hundreds of times, clearing cache every time.. The results vary from time to time as server load varies, but almost always count(*) has higher cpu time.

Password must have at least one non-alpha character

  function randomPassword(length) {
        var chars = "abcdefghijklmnopqrstuvwxyz#$%ABCDEFGHIJKLMNOP1234567890";
        var pass = "";
        for (var x = 0; x < length; x++) {
            var i = Math.floor(Math.random() * chars.length);
            pass += chars.charAt(i);
        }
        var pattern = false;
        var passwordpattern = new RegExp("[^a-zA-Z0-9+]+[0-9+]+[A-Z+]+[a-z+]");
        pattern = passwordpattern.test(pass);
        if (pattern == true)
            { alert(pass); }
        else
         { randomPassword(length); }
    }

try this to create the random password with atleast one special character

JavaScript Chart Library

There is another javascript library based on SVG. It is called Protovis and it comes from Stanford Visualization Group

It also allows making nice interactive graphics and visualizations.

http://vis.stanford.edu/protovis/ex/

Although it is only for modern web browsers

UPDATE: The protovis team has moved to another library called d3.js (Data Driven Documents) as they said:

"The Protovis team is now developing a new visualization library, D3.js, with improved support for animation and interaction. D3 builds on many of the concepts in Protovis"

The new library can now be found in:

http://mbostock.github.com/d3/

UPDATE 2:

"Rickshaw" is a JavaScript toolkit for creating interactive time series graphs. Based on d3.js that simplifies a lot the work with d3.js although is a little bit less powerful.

http://code.shutterstock.com/rickshaw/

Hide all warnings in ipython

I eventually figured it out. Place:

import warnings
warnings.filterwarnings('ignore')

inside ~/.ipython/profile_default/startup/disable-warnings.py. I'm leaving this question and answer for the record in case anyone else comes across the same issue.

Quite often it is useful to see a warning once. This can be set by:

warnings.filterwarnings(action='once')

Java Inheritance - calling superclass method

You can't call alpha's alphaMethod1() by using beta's object But you have two solutions:

solution 1: call alpha's alphaMethod1() from beta's alphaMethod1()

class Beta extends Alpha
{
  public void alphaMethod1()
  {
    super.alphaMethod1();
  }
}

or from any other method of Beta like:

class Beta extends Alpha
{
  public void foo()
  {
     super.alphaMethod1();
  }
}

class Test extends Beta 
{
   public static void main(String[] args)
   {
      Beta beta = new Beta();
      beta.foo();
   }
}

solution 2: create alpha's object and call alpha's alphaMethod1()

class Test extends Beta
{
   public static void main(String[] args)
   {
      Alpha alpha = new Alpha();
      alpha.alphaMethod1();
   }
}

How to crop(cut) text files based on starting and ending line-numbers in cygwin?

I saw this thread when I was trying to split a file in files with 100 000 lines. A better solution than sed for that is:

split -l 100000 database.sql database-

It will give files like:

database-aaa
database-aab
database-aac
...

How to copy a row and insert in same table with a autoincrement field in MySQL?

Say the table is user(id, user_name, user_email).

You can use this query:

INSERT INTO user (SELECT NULL,user_name, user_email FROM user WHERE id = 1)

How to cut first n and last n columns?

You can use Bash for that:

while read -a cols; do echo ${cols[@]:0:1} ${cols[@]:1,-1}; done < file.txt

How is the java memory pool divided?

Java Heap Memory is part of memory allocated to JVM by Operating System.

Objects reside in an area called the heap. The heap is created when the JVM starts up and may increase or decrease in size while the application runs. When the heap becomes full, garbage is collected.

enter image description here

You can find more details about Eden Space, Survivor Space, Tenured Space and Permanent Generation in below SE question:

Young , Tenured and Perm generation

PermGen has been replaced with Metaspace since Java 8 release.

Regarding your queries:

  1. Eden Space, Survivor Space, Tenured Space are part of heap memory
  2. Metaspace and Code Cache are part of non-heap memory.

Codecache: The Java Virtual Machine (JVM) generates native code and stores it in a memory area called the codecache. The JVM generates native code for a variety of reasons, including for the dynamically generated interpreter loop, Java Native Interface (JNI) stubs, and for Java methods that are compiled into native code by the just-in-time (JIT) compiler. The JIT is by far the biggest user of the codecache.

PHP refresh window? equivalent to F5 page reload?

with php you can use two redirections. It works same as refresh in some issues.

you can use a page redirect.php and post your last url to it by GET method (for example). then in redirect.php you can change header to location you`ve sent to it by GET method.

like this: your page:

<?php
header("location:redirec.php?ref=".$your_url);
?>

redirect.php:

<?php
$ref_url=$_GET["ref"];
header("location:redirec.php?ref=".$ref_url);
?>

that worked for me good.

Warning: mysqli_query() expects at least 2 parameters, 1 given. What?

The issue is that you're not saving the mysqli connection. Change your connect to:

$aVar = mysqli_connect('localhost','tdoylex1_dork','dorkk','tdoylex1_dork');

And then include it in your query:

$query1 = mysqli_query($aVar, "SELECT name1 FROM users
    ORDER BY RAND()
    LIMIT 1");
$aName1 = mysqli_fetch_assoc($query1);
$name1 = $aName1['name1'];

Also don't forget to enclose your connections variables as strings as I have above. This is what's causing the error but you're using the function wrong, mysqli_query returns a query object but to get the data out of this you need to use something like mysqli_fetch_assoc http://php.net/manual/en/mysqli-result.fetch-assoc.php to actually get the data out into a variable as I have above.

Delete statement in SQL is very slow

If the table you are deleting from has BEFORE/AFTER DELETE triggers, something in there could be causing your delay.

Additionally, if you have foreign keys referencing that table, additional UPDATEs or DELETEs may be occurring.

What is the difference between HTTP and REST?

REST APIs must be hypertext-driven

From Roy Fielding's blog here's a set of ways to check if you're building a HTTP API or a REST API:

API designers, please note the following rules before calling your creation a REST API:

  • A REST API should not be dependent on any single communication protocol, though its successful mapping to a given protocol may be dependent on the availability of metadata, choice of methods, etc. In general, any protocol element that uses a URI for identification must allow any URI scheme to be used for the sake of that identification. [Failure here implies that identification is not separated from interaction.]
  • A REST API should not contain any changes to the communication protocols aside from filling-out or fixing the details of underspecified bits of standard protocols, such as HTTP’s PATCH method or Link header field. Workarounds for broken implementations (such as those browsers stupid enough to believe that HTML defines HTTP’s method set) should be defined separately, or at least in appendices, with an expectation that the workaround will eventually be obsolete. [Failure here implies that the resource interfaces are object-specific, not generic.]
  • A REST API should spend almost all of its descriptive effort in defining the media type(s) used for representing resources and driving application state, or in defining extended relation names and/or hypertext-enabled mark-up for existing standard media types. Any effort spent describing what methods to use on what URIs of interest should be entirely defined within the scope of the processing rules for a media type (and, in most cases, already defined by existing media types). [Failure here implies that out-of-band information is driving interaction instead of hypertext.]
  • A REST API must not define fixed resource names or hierarchies (an obvious coupling of client and server). Servers must have the freedom to control their own namespace. Instead, allow servers to instruct clients on how to construct appropriate URIs, such as is done in HTML forms and URI templates, by defining those instructions within media types and link relations. [Failure here implies that clients are assuming a resource structure due to out-of band information, such as a domain-specific standard, which is the data-oriented equivalent to RPC’s functional coupling].
  • A REST API should never have “typed” resources that are significant to the client. Specification authors may use resource types for describing server implementation behind the interface, but those types must be irrelevant and invisible to the client. The only types that are significant to a client are the current representation’s media type and standardized relation names. [ditto]
  • A REST API should be entered with no prior knowledge beyond the initial URI (bookmark) and set of standardized media types that are appropriate for the intended audience (i.e., expected to be understood by any client that might use the API). From that point on, all application state transitions must be driven by client selection of server-provided choices that are present in the received representations or implied by the user’s manipulation of those representations. The transitions may be determined (or limited by) the client’s knowledge of media types and resource communication mechanisms, both of which may be improved on-the-fly (e.g., code-on-demand). [Failure here implies that out-of-band information is driving interaction instead of hypertext.]

What is the path for the startup folder in windows 2008 server

SHGetKnownFolderPath:

Retrieves the full path of a known folder identified by the folder's KNOWNFOLDERID.

And, FOLDERID_CommonStartup:

Default Path %ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\StartUp

There are also managed equivalents, but you haven't told us what you're programming in.

"Could not find bundler" error

If you're using rbenv running rbenv rehash can solve this after you've installed bundler and are still getting the issue.

First char to upper case

For completeness, if you wanted to use replaceFirst, try this:

public static String cap1stChar(String userIdea)
{
  String betterIdea = userIdea;
  if (userIdea.length() > 0)
  {
    String first = userIdea.substring(0,1);
    betterIdea = userIdea.replaceFirst(first, first.toUpperCase());
  }
  return betterIdea;
}//end cap1stChar

Regex for Comma delimited list

You might want to specify language just to be safe, but

(\d+, ?)+(\d+)?

ought to work

Detect when browser receives file download

In my experience, there are two ways to handle this:

  1. Set a short-lived cookie on the download, and have JavaScript continually check for its existence. Only real issue is getting the cookie lifetime right - too short and the JS can miss it, too long and it might cancel the download screens for other downloads. Using JS to remove the cookie upon discovery usually fixes this.
  2. Download the file using fetch/XHR. Not only do you know exactly when the file download finishes, if you use XHR you can use progress events to show a progress bar! Save the resulting blob with msSaveBlob in IE/Edge and a download link (like this one) in Firefox/Chrome. The problem with this method is that iOS Safari doesn't seem to handle downloading blobs right - you can convert the blob into a data URL with a FileReader and open that in a new window, but that's opening the file, not saving it.

Cleanest way to build an SQL string in Java

You can also have a look at MyBatis (www.mybatis.org) . It helps you write SQL statements outside your java code and maps the sql results into your java objects among other things.

Adding a column after another column within SQL

Assuming MySQL (EDIT: posted before the SQL variant was supplied):

ALTER TABLE myTable ADD myNewColumn VARCHAR(255) AFTER myOtherColumn

The AFTER keyword tells MySQL where to place the new column. You can also use FIRST to flag the new column as the first column in the table.

Why does Eclipse complain about @Override on interface methods?

I understood your problem, change your jdk from your jdk to greaterthan 1.5

No appenders could be found for logger(log4j)?

First import:

 import org.apache.log4j.PropertyConfigurator;

Then add below code to main method:

String log4jConfPath ="path to/log4j.properties";
PropertyConfigurator.configure(log4jConfPath);

Create a file at path to and add the below code to that file.

log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{2}: %m%n

How do I clear a search box with an 'x' in bootstrap 3?

Here is my working solution with search and clear icon for Angularjs\Bootstrap with CSS.

    <div class="form-group has-feedback has-clear">
                    <input type="search" class="form-control removeXicon" ng-model="filter" style="max-width:100%" placeholder="Search..." />
                    <div ng-switch on="!!filter">
                        <div ng-switch-when="false">
                            <span class="glyphicon glyphicon-search form-control-feedback"></span>
                        </div>
                        <div ng-switch-when="true">
                            <span class="glyphicon glyphicon-remove-sign form-control-feedback" ng-click="$parent.filter = ''" style="pointer-events: auto; text-decoration: none;cursor: pointer;"></span>
                        </div>
                    </div>                        
                </div>

------

CSS

/* hide the built-in IE10+ clear field icon */
.removeXicon::-ms-clear {
  display: none;
}

/* hide the built-in chrome clear field icon */
.removeXicon::-webkit-search-decoration,
.removeXicon::-webkit-search-cancel-button,
.removeXicon::-webkit-search-results-button,
.removeXicon::-webkit-search-results-decoration { 
      display: none; 
}

WooCommerce: Finding the products in database

Update 2020

Products are located mainly in the following tables:

  • wp_posts table with post_type like product (or product_variation),

  • wp_postmeta table with post_id as relational index (the product ID).

  • wp_wc_product_meta_lookup table with product_id as relational index (the post ID) | Allow fast queries on specific product data (since WooCommerce 3.7)

  • wp_wc_order_product_lookuptable with product_id as relational index (the post ID) | Allow fast queries to retrieve products on orders (since WooCommerce 3.7)

Product types, categories, subcategories, tags, attributes and all other custom taxonomies are located in the following tables:

  • wp_terms

  • wp_termmeta

  • wp_term_taxonomy

  • wp_term_relationships - column object_id as relational index (the product ID)

  • wp_woocommerce_termmeta

  • wp_woocommerce_attribute_taxonomies (for product attributes only)

  • wp_wc_category_lookup (for product categories hierarchy only since WooCommerce 3.7)


Product types are handled by custom taxonomy product_type with the following default terms:

  • simple
  • grouped
  • variable
  • external

Some other product types for Subscriptions and Bookings plugins:

  • subscription
  • variable-subscription
  • booking

Since Woocommerce 3+ a new custom taxonomy named product_visibility handle:

  • The product visibility with the terms exclude-from-search and exclude-from-catalog
  • The feature products with the term featured
  • The stock status with the term outofstock
  • The rating system with terms from rated-1 to rated-5

Particular feature: Each product attribute is a custom taxonomy…


References:

Use of *args and **kwargs

Here's one of my favorite places to use the ** syntax as in Dave Webb's final example:

mynum = 1000
mystr = 'Hello World!'
print("{mystr} New-style formatting is {mynum}x more fun!".format(**locals()))

I'm not sure if it's terribly fast when compared to just using the names themselves, but it's a lot easier to type!

CSS3 100vh not constant in mobile browser

The VH 100 does not work well on mobile as it does not factor in the iOS bar (or similar functionality on other platforms).

One solution that works well is to use JavaScript "window.innerHeight".

Simply assign the height of the element to this value e.g. $('.element-name').height(window.innerHeight);

Note: It may be useful to create a function in JS, so that the height can change when the screen is resized. However, I would suggest only calling the function when the width of the screen is changed, this way the element will not jump in height when the iOS bar disappears when the user scrolls down the page.

Uploading images using Node.js, Express, and Mongoose

Again if you don't want to use bodyParser, the following works:

var express = require('express');
var http = require('http');
var app = express();

app.use(express.static('./public'));


app.configure(function(){
    app.use(express.methodOverride());
    app.use(express.multipart({
        uploadDir: './uploads',
        keepExtensions: true
    }));
});


app.use(app.router);

app.get('/upload', function(req, res){
    // Render page with upload form
    res.render('upload');
});

app.post('/upload', function(req, res){
    // Returns json of uploaded file
    res.json(req.files);
});

http.createServer(app).listen(3000, function() {
    console.log('App started');
});

Oracle PL/SQL - Raise User-Defined Exception With Custom SQLERRM

You could use RAISE_APPLICATION_ERROR like this:

DECLARE
    ex_custom       EXCEPTION;
BEGIN
    RAISE ex_custom;
EXCEPTION
    WHEN ex_custom THEN
        RAISE_APPLICATION_ERROR(-20001,'My exception was raised');
END;
/

That will raise an exception that looks like:

ORA-20001: My exception was raised

The error number can be anything between -20001 and -20999.

how to use font awesome in own css?

The spirit of Web font is to use cache as much as possible, therefore you should use CDN version between <head></head> instead of hosting yourself:

<link href="//netdna.bootstrapcdn.com/font-awesome/3.2.1/css/font-awesome.css" rel="stylesheet">

Also, make sure you loaded your CSS AFTER the above line, or your custom font CSS won't work.

Reference: Font Awesome Get Started

How to pick an image from gallery (SD Card) for my app?

#initialize in main activity 
    path = Environment.getExternalStorageDirectory()
            + "/images/make_machine_example.jpg"; #
     ImageView image=(ImageView)findViewById(R.id.image);
 //--------------------------------------------------||

 public void FromCamera(View) {

    Log.i("camera", "startCameraActivity()");
    File file = new File(path);
    Uri outputFileUri = Uri.fromFile(file);
    Intent intent = new Intent(
            android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
    startActivityForResult(intent, 1);

}

public void FromCard() {
    Intent i = new Intent(Intent.ACTION_PICK,
            android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    startActivityForResult(i, 2);
}

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

    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == 2 && resultCode == RESULT_OK
            && null != data) {

        Uri selectedImage = data.getData();
        String[] filePathColumn = { MediaStore.Images.Media.DATA };

        Cursor cursor = getContentResolver().query(selectedImage,
                filePathColumn, null, null, null);
        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        String picturePath = cursor.getString(columnIndex);
        cursor.close();

        bitmap = BitmapFactory.decodeFile(picturePath);
        image.setImageBitmap(bitmap);

        if (bitmap != null) {
            ImageView rotate = (ImageView) findViewById(R.id.rotate);

        }

    } else {

        Log.i("SonaSys", "resultCode: " + resultCode);
        switch (resultCode) {
        case 0:
            Log.i("SonaSys", "User cancelled");
            break;
        case -1:
            onPhotoTaken();
            break;

        }

    }

}

protected void onPhotoTaken() {
    // Log message
    Log.i("SonaSys", "onPhotoTaken");
    taken = true;
    imgCapFlag = true;
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 4;
    bitmap = BitmapFactory.decodeFile(path, options);
    image.setImageBitmap(bitmap);


}

How to find elements with 'value=x'?

$('#attached_docs [value="123"]').find ... .remove();

it should do your need however, you cannot duplicate id! remember it

Should IBOutlets be strong or weak under ARC?

From WWDC 2015 there is a session on Implementing UI Designs in Interface Builder. Around the 32min mark he says that you always want to make your @IBOutlet strong.

How to go back to previous page if back button is pressed in WebView?

This is my solution. It works also in Fragment.

webView.setOnKeyListener(new OnKeyListener()
{
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event)
    {
        if(event.getAction() == KeyEvent.ACTION_DOWN)
        {
            WebView webView = (WebView) v;

            switch(keyCode)
            {
                case KeyEvent.KEYCODE_BACK:
                    if(webView.canGoBack())
                    {
                        webView.goBack();
                        return true;
                    }
                    break;
            }
        }

        return false;
    }
});

Task<> does not contain a definition for 'GetAwaiter'

If you are writing a Visual Studio Extension (VSIX) then ensure that you have a using statement for Microsoft.VisualStudio.Threading, as such:

using Microsoft.VisualStudio.Threading;

Comparing Dates in Oracle SQL

Single quote must be there, since date converted to character.

Select employee_id, count(*)
From Employee
Where to_char(employee_date_hired, 'DD-MON-YY') > '31-DEC-95';

PostgreSQL query to list all table names?

What bout this query (based on the description from manual)?

SELECT table_name
  FROM information_schema.tables
 WHERE table_schema='public'
   AND table_type='BASE TABLE';

Git: Recover deleted (remote) branch

I think that you have a mismatched config for 'fetch' and 'push' so this has caused default fetch/push to not round trip properly. Fortunately you have fetched the branches that you subsequently deleted so you should be able to recreate them with an explicit push.

git push origin origin/contact_page:contact_page origin/new_pictures:new_pictures

How to deploy a war file in JBoss AS 7?

open up console and navigate to bin folder and run

JBOSS_HOME/bin > stanalone.sh

Once it is up and running just copy past your war file in

standalone/deployments folder

Thats probably it for jboss 7.1

Use of for_each on map elements

Just an example:

template <class key, class value>
class insertIntoVec
{
public:
    insertIntoVec(std::vector<value>& vec_in):m_vec(vec_in)
    {}

    void operator () (const std::pair<key, value>& rhs)  
    {   
        m_vec.push_back(rhs.second);
    }

private:
    std::vector<value>& m_vec;
};

int main()
{
std::map<int, std::string> aMap;
aMap[1] = "test1";
aMap[2] = "test2";
aMap[3] = "test3";
aMap[4] = "test4";

std::vector<std::string> aVec;

aVec.reserve(aMap.size());
std::for_each(aMap.begin(), aMap.end(),
          insertIntoVec<int, std::string>(aVec) 
    );

}

Print DIV content by JQuery

I prefer this one, I have tested it and its working

https://github.com/jasonday/printThis

$("#mySelector").printThis();

or

$("#mySelector").printThis({
*      debug: false,              * show the iframe for debugging
*      importCSS: true,           * import page CSS
*      printContainer: true,      * grab outer container as well as the contents of the selector
*      loadCSS: "path/to/my.css", * path to additional css file
*      pageTitle: "",             * add title to print page
*      removeInline: false        * remove all inline styles from print elements
*  });

How to set delay in android?

You can use this:

import java.util.Timer;

and for the delay itself, add:

 new Timer().schedule(
                    new TimerTask(){
                
                        @Override
                        public void run(){
                            
                        //if you need some code to run when the delay expires
                        }
                        
                    }, delay);

where the delay variable is in milliseconds; for example set delay to 5000 for a 5-second delay.

Decoding and verifying JWT token using System.IdentityModel.Tokens.Jwt

Within the package there is a class called JwtSecurityTokenHandler which derives from System.IdentityModel.Tokens.SecurityTokenHandler. In WIF this is the core class for deserialising and serialising security tokens.

The class has a ReadToken(String) method that will take your base64 encoded JWT string and returns a SecurityToken which represents the JWT.

The SecurityTokenHandler also has a ValidateToken(SecurityToken) method which takes your SecurityToken and creates a ReadOnlyCollection<ClaimsIdentity>. Usually for JWT, this will contain a single ClaimsIdentity object that has a set of claims representing the properties of the original JWT.

JwtSecurityTokenHandler defines some additional overloads for ValidateToken, in particular, it has a ClaimsPrincipal ValidateToken(JwtSecurityToken, TokenValidationParameters) overload. The TokenValidationParameters argument allows you to specify the token signing certificate (as a list of X509SecurityTokens). It also has an overload that takes the JWT as a string rather than a SecurityToken.

The code to do this is rather complicated, but can be found in the Global.asax.cx code (TokenValidationHandler class) in the developer sample called "ADAL - Native App to REST service - Authentication with ACS via Browser Dialog", located at

http://code.msdn.microsoft.com/AAL-Native-App-to-REST-de57f2cc

Alternatively, the JwtSecurityToken class has additional methods that are not on the base SecurityToken class, such as a Claims property that gets the contained claims without going via the ClaimsIdentity collection. It also has a Payload property that returns a JwtPayload object that lets you get at the raw JSON of the token. It depends on your scenario which approach it most appropriate.

The general (i.e. non JWT specific) documentation for the SecurityTokenHandler class is at

http://msdn.microsoft.com/en-us/library/system.identitymodel.tokens.securitytokenhandler.aspx

Depending on your application, you can configure the JWT handler into the WIF pipeline exactly like any other handler.

There are 3 samples of it in use in different types of application at

http://code.msdn.microsoft.com/site/search?f%5B0%5D.Type=SearchText&f%5B0%5D.Value=aal&f%5B1%5D.Type=User&f%5B1%5D.Value=Azure%20AD%20Developer%20Experience%20Team&f%5B1%5D.Text=Azure%20AD%20Developer%20Experience%20Team

Probably, one will suite your needs or at least be adaptable to them.

commands not found on zsh

It's evident that you've managed to mess up your PATH variable. (Your current PATH doesn't contain any location where common utilities are located.)

Try:

PATH=/bin:/usr/bin:/usr/local/bin:${PATH}
export PATH

Alternatively, for "resetting" zsh, specify the complete path to the shell:

exec /bin/zsh

or

exec /usr/bin/zsh

In Java, how do I convert a byte array to a string of hex digits while keeping leading zeros?

This what I am using for MD5 hashes:

public static String getMD5(String filename)
        throws NoSuchAlgorithmException, IOException {
    MessageDigest messageDigest = 
        java.security.MessageDigest.getInstance("MD5");

    InputStream in = new FileInputStream(filename);

    byte [] buffer = new byte[8192];
    int len = in.read(buffer, 0, buffer.length);

    while (len > 0) {
        messageDigest.update(buffer, 0, len);
        len = in.read(buffer, 0, buffer.length);
    }
    in.close();

    return new BigInteger(1, messageDigest.digest()).toString(16);
}

EDIT: I've tested and I've noticed that with this also trailing zeros are cut. But this can only happen in the beginning, so you can compare with the expected length and pad accordingly.

How can I define an array of objects?

Some tslint rules are disabling use of [], example message: Array type using 'T[]' is forbidden for non-simple types. Use 'Array<T>' instead.

Then you would write it like:

var userTestStatus: Array<{ id: number, name: string }> = Array(
    { "id": 0, "name": "Available" },
    { "id": 1, "name": "Ready" },
    { "id": 2, "name": "Started" }
);

How to post JSON to PHP with curl

Jordans analysis of why the $_POST-array isn't populated is correct. However, you can use

$data = file_get_contents("php://input");

to just retrieve the http body and handle it yourself. See PHP input/output streams.

From a protocol perspective this is actually more correct, since you're not really processing http multipart form data anyway. Also, use application/json as content-type when posting your request.

Extract values in Pandas value_counts()

#!/usr/bin/env python

import pandas as pd

# Make example dataframe
df = pd.DataFrame([(1, 'Germany'),
                   (2, 'France'),
                   (3, 'Indonesia'),
                   (4, 'France'),
                   (5, 'France'),
                   (6, 'Germany'),
                   (7, 'UK'),
                   ],
                  columns=['groupid', 'country'],
                  index=['a', 'b', 'c', 'd', 'e', 'f', 'g'])

# What you're looking for
values = df['country'].value_counts().keys().tolist()
counts = df['country'].value_counts().tolist()

Now, print(df['country'].value_counts()) gives:

France       3
Germany      2
UK           1
Indonesia    1

and print(values) gives:

['France', 'Germany', 'UK', 'Indonesia']

and print(counts) gives:

[3, 2, 1, 1]

When to use CouchDB over MongoDB and vice versa

Be aware of an issue with sparse unique indexes in MongoDB. I've hit it and it is extremely cumbersome to workaround.

The problem is this - you have a field, which is unique if present and you wish to find all the objects where the field is absent. The way sparse unique indexes are implemented in Mongo is that objects where that field is missing are not in the index at all - they cannot be retrieved by a query on that field - {$exists: false} just does not work.

The only workaround I have come up with is having a special null family of values, where an empty value is translated to a special prefix (like null:) concatenated to a uuid. This is a real headache, because one has to take care of transforming to/from the empty values when writing/quering/reading. A major nuisance.

I have never used server side javascript execution in MongoDB (it is not advised anyway) and their map/reduce has awful performance when there is just one Mongo node. Because of all these reasons I am now considering to check out CouchDB, maybe it fits more to my particular scenario.

BTW, if anyone knows the link to the respective Mongo issue describing the sparse unique index problem - please share.

How to close a Java Swing application from the code

May be the safe way is something like:

    private JButton btnExit;
    ...
    btnExit = new JButton("Quit");      
    btnExit.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e){
            Container frame = btnExit.getParent();
            do 
                frame = frame.getParent(); 
            while (!(frame instanceof JFrame));                                      
            ((JFrame) frame).dispose();
        }
    });

Disable button in jQuery

This works for me:

<script type="text/javascript">
function change(){
    document.getElementById("submit").disabled = false;
}
</script>

Check if space is in a string

== takes precedence over in, so you're actually testing word == True.

>>> w = 'ab c'
>>> ' ' in w == True
1: False
>>> (' ' in w) == True
2: True

But you don't need == True at all. if requires [something that evalutes to True or False] and ' ' in word will evalute to true or false. So, if ' ' in word: ... is just fine:

>>> ' ' in w
3: True

Java division by zero doesnt throw an ArithmeticException - why?

When divided by zero

  1. If you divide double by 0, JVM will show Infinity.

    public static void main(String [] args){ double a=10.00; System.out.println(a/0); }
    

    Console: Infinity

  2. If you divide int by 0, then JVM will throw Arithmetic Exception.

    public static void main(String [] args){
        int a=10;
        System.out.println(a/0);
    }
    

    Console: Exception in thread "main" java.lang.ArithmeticException: / by zero

taking input of a string word by word

Put the line in a stringstream and extract word by word back:

#include <iostream>
#include <sstream>
using namespace std;

int main()
{
    string t;
    getline(cin,t);

    istringstream iss(t);
    string word;
    while(iss >> word) {
        /* do stuff with word */
    }
}

Of course, you can just skip the getline part and read word by word from cin directly.

And here you can read why is using namespace std considered bad practice.

Understanding PrimeFaces process/update and JSF f:ajax execute/render attributes

<p:commandXxx process> <p:ajax process> <f:ajax execute>

The process attribute is server side and can only affect UIComponents implementing EditableValueHolder (input fields) or ActionSource (command fields). The process attribute tells JSF, using a space-separated list of client IDs, which components exactly must be processed through the entire JSF lifecycle upon (partial) form submit.

JSF will then apply the request values (finding HTTP request parameter based on component's own client ID and then either setting it as submitted value in case of EditableValueHolder components or queueing a new ActionEvent in case of ActionSource components), perform conversion, validation and updating the model values (EditableValueHolder components only) and finally invoke the queued ActionEvent (ActionSource components only). JSF will skip processing of all other components which are not covered by process attribute. Also, components whose rendered attribute evaluates to false during apply request values phase will also be skipped as part of safeguard against tampered requests.

Note that it's in case of ActionSource components (such as <p:commandButton>) very important that you also include the component itself in the process attribute, particularly if you intend to invoke the action associated with the component. So the below example which intends to process only certain input component(s) when a certain command component is invoked ain't gonna work:

<p:inputText id="foo" value="#{bean.foo}" />
<p:commandButton process="foo" action="#{bean.action}" />

It would only process the #{bean.foo} and not the #{bean.action}. You'd need to include the command component itself as well:

<p:inputText id="foo" value="#{bean.foo}" />
<p:commandButton process="@this foo" action="#{bean.action}" />

Or, as you apparently found out, using @parent if they happen to be the only components having a common parent:

<p:panel><!-- Type doesn't matter, as long as it's a common parent. -->
    <p:inputText id="foo" value="#{bean.foo}" />
    <p:commandButton process="@parent" action="#{bean.action}" />
</p:panel>

Or, if they both happen to be the only components of the parent UIForm component, then you can also use @form:

<h:form>
    <p:inputText id="foo" value="#{bean.foo}" />
    <p:commandButton process="@form" action="#{bean.action}" />
</h:form>

This is sometimes undesirable if the form contains more input components which you'd like to skip in processing, more than often in cases when you'd like to update another input component(s) or some UI section based on the current input component in an ajax listener method. You namely don't want that validation errors on other input components are preventing the ajax listener method from being executed.

Then there's the @all. This has no special effect in process attribute, but only in update attribute. A process="@all" behaves exactly the same as process="@form". HTML doesn't support submitting multiple forms at once anyway.

There's by the way also a @none which may be useful in case you absolutely don't need to process anything, but only want to update some specific parts via update, particularly those sections whose content doesn't depend on submitted values or action listeners.

Noted should be that the process attribute has no influence on the HTTP request payload (the amount of request parameters). Meaning, the default HTML behavior of sending "everything" contained within the HTML representation of the <h:form> will be not be affected. In case you have a large form, and want to reduce the HTTP request payload to only these absolutely necessary in processing, i.e. only these covered by process attribute, then you can set the partialSubmit attribute in PrimeFaces Ajax components as in <p:commandXxx ... partialSubmit="true"> or <p:ajax ... partialSubmit="true">. You can also configure this 'globally' by editing web.xml and add

<context-param>
    <param-name>primefaces.SUBMIT</param-name>
    <param-value>partial</param-value>
</context-param>

Alternatively, you can also use <o:form> of OmniFaces 3.0+ which defaults to this behavior.

The standard JSF equivalent to the PrimeFaces specific process is execute from <f:ajax execute>. It behaves exactly the same except that it doesn't support a comma-separated string while the PrimeFaces one does (although I personally recommend to just stick to space-separated convention), nor the @parent keyword. Also, it may be useful to know that <p:commandXxx process> defaults to @form while <p:ajax process> and <f:ajax execute> defaults to @this. Finally, it's also useful to know that process supports the so-called "PrimeFaces Selectors", see also How do PrimeFaces Selectors as in update="@(.myClass)" work?


<p:commandXxx update> <p:ajax update> <f:ajax render>

The update attribute is client side and can affect the HTML representation of all UIComponents. The update attribute tells JavaScript (the one responsible for handling the ajax request/response), using a space-separated list of client IDs, which parts in the HTML DOM tree need to be updated as response to the form submit.

JSF will then prepare the right ajax response for that, containing only the requested parts to update. JSF will skip all other components which are not covered by update attribute in the ajax response, hereby keeping the response payload small. Also, components whose rendered attribute evaluates to false during render response phase will be skipped. Note that even though it would return true, JavaScript cannot update it in the HTML DOM tree if it was initially false. You'd need to wrap it or update its parent instead. See also Ajax update/render does not work on a component which has rendered attribute.

Usually, you'd like to update only the components which really need to be "refreshed" in the client side upon (partial) form submit. The example below updates the entire parent form via @form:

<h:form>
    <p:inputText id="foo" value="#{bean.foo}" required="true" />
    <p:message id="foo_m" for="foo" />
    <p:inputText id="bar" value="#{bean.bar}" required="true" />
    <p:message id="bar_m" for="bar" />
    <p:commandButton action="#{bean.action}" update="@form" />
</h:form>

(note that process attribute is omitted as that defaults to @form already)

Whilst that may work fine, the update of input and command components is in this particular example unnecessary. Unless you change the model values foo and bar inside action method (which would in turn be unintuitive in UX perspective), there's no point of updating them. The message components are the only which really need to be updated:

<h:form>
    <p:inputText id="foo" value="#{bean.foo}" required="true" />
    <p:message id="foo_m" for="foo" />
    <p:inputText id="bar" value="#{bean.bar}" required="true" />
    <p:message id="bar_m" for="bar" />
    <p:commandButton action="#{bean.action}" update="foo_m bar_m" />
</h:form>

However, that gets tedious when you have many of them. That's one of the reasons why PrimeFaces Selectors exist. Those message components have in the generated HTML output a common style class of ui-message, so the following should also do:

<h:form>
    <p:inputText id="foo" value="#{bean.foo}" required="true" />
    <p:message id="foo_m" for="foo" />
    <p:inputText id="bar" value="#{bean.bar}" required="true" />
    <p:message id="bar_m" for="bar" />
    <p:commandButton action="#{bean.action}" update="@(.ui-message)" />
</h:form>

(note that you should keep the IDs on message components, otherwise @(...) won't work! Again, see How do PrimeFaces Selectors as in update="@(.myClass)" work? for detail)

The @parent updates only the parent component, which thus covers the current component and all siblings and their children. This is more useful if you have separated the form in sane groups with each its own responsibility. The @this updates, obviously, only the current component. Normally, this is only necessary when you need to change one of the component's own HTML attributes in the action method. E.g.

<p:commandButton action="#{bean.action}" update="@this" 
    oncomplete="doSomething('#{bean.value}')" />

Imagine that the oncomplete needs to work with the value which is changed in action, then this construct wouldn't have worked if the component isn't updated, for the simple reason that oncomplete is part of generated HTML output (and thus all EL expressions in there are evaluated during render response).

The @all updates the entire document, which should be used with care. Normally, you'd like to use a true GET request for this instead by either a plain link (<a> or <h:link>) or a redirect-after-POST by ?faces-redirect=true or ExternalContext#redirect(). In effects, process="@form" update="@all" has exactly the same effect as a non-ajax (non-partial) submit. In my entire JSF career, the only sensible use case I encountered for @all is to display an error page in its entirety in case an exception occurs during an ajax request. See also What is the correct way to deal with JSF 2.0 exceptions for AJAXified components?

The standard JSF equivalent to the PrimeFaces specific update is render from <f:ajax render>. It behaves exactly the same except that it doesn't support a comma-separated string while the PrimeFaces one does (although I personally recommend to just stick to space-separated convention), nor the @parent keyword. Both update and render defaults to @none (which is, "nothing").


See also:

PHP Function Comments

You must check this: Docblock Comment standards

http://pear.php.net/manual/en/standards.sample.php

when I run mockito test occurs WrongTypeOfReturnValue Exception

I recently had this issue. The problem was that the method I was trying to mock had no access modifier. Adding public solved the problem.

How to use \n new line in VB msgbox() ...?

Try using vbcrlf for a newline

msgbox "This is how" & vbcrlf & "to get a new line"

Write a file in external storage in Android

Even though above answers are correct, I wanna add a notice to distinguish types of storage:

  • Internal storage: It should say 'private storage' because it belongs to the app and cannot be shared. Where it's saved is based on where the app installed. If the app was installed on an SD card (I mean the external storage card you put more into a cell phone for more space to store images, videos, ...), your file will belong to the app means your file will be in an SD card. And if the app was installed on an Internal card (I mean the onboard storage card coming with your cell phone), your file will be in an Internal card.
  • External storage: It should say 'public storage' because it can be shared. And this mode divides into 2 groups: private external storage and public external storage. Basically, they are nearly the same, you can consult more from this site: https://developer.android.com/training/data-storage/files
  • A real SD card (I mean the external storage card you put more into a cell phone for more space to store images, videos, ...): this was not stated clearly on Android docs, so many people might be confused with how to save files in this card.

Here is the link to source code for cases I mentioned above: https://github.com/mttdat/utils/blob/master/utils/src/main/java/mttdat/utils/FileUtils.java

What is the best free SQL GUI for Linux for various DBMS systems

I use SQLite Database Browser for SQLite3 currently and it's pretty useful. Works across Windows/OS X/Linux and is lightweight and fast. Slightly unstable with executing SQL on the DB if it's incorrectly formatted.

Edit: I have recently discovered SQLite Manager, a plugin for Firefox. Obviously you need to run Firefox, but you can close all windows and just run it "standalone". It's very feature complete, amazingly stable and it remembers your databases! It has tonnes of features so I've moved away from SQLite Database Browser as the instability and lack of features is too much to bear.

How do I make an image smaller with CSS?

CSS 3 introduces the background-size property, but support is not universal.

Having the browser resize the image is inefficient though, the large image still has to be downloaded. You should resize it server side (caching the result) and use that instead. It will use less bandwidth and work in more browsers.

What are the options for (keyup) in Angular2?

you can add keyup event like this

template: `
  <input (keyup)="onKey($event)">
  <p>{{values}}</p>
`

in Component, code some like below

export class KeyUpComponent_v1 {
  values = '';

  onKey(event:any) { // without type info
    this.values += event.target.value + ' | ';
  }
}

Replace text in HTML page with jQuery

...I have a string "-9o0-9909" and I want to replace it with another string.

The code below will do that.

var str = '-9o0-9909';

str = 'new string';

Jokes aside, replacing text nodes is not trivial with JavaScript.

I've written a post about this: Replacing text with JavaScript.

Printing prime numbers from 1 through 100

Here is my implementation of Sieve of Eratosthenes (for primes between 2 & n)

#include <iostream>

int main (){
int n=0;
std::cout << "n = ";
std::cin >> n;
std::cout << std::endl;

if (n==0 || n==1){
    std::cout << "No primes in this range" << std::endl;
    return 0;
}


const int array_len = n-2+1;

int the_int_array[array_len];
for (int counter=2; counter <=n; counter++)
    the_int_array[counter-2]=counter;


int runner = 0;
int new_runner = 0;

while (runner < array_len ){
    if (the_int_array[runner]!=0){
        new_runner = runner;
        new_runner = new_runner + the_int_array[runner];

        while (new_runner < array_len){
           the_int_array[new_runner] = 0;
           new_runner = (new_runner + the_int_array[runner]);
        }
    }
runner++;
}

runner = 0;

while (runner < array_len ){
    if (the_int_array[runner]!=0)
        std::cout << the_int_array[runner] << " ";
    runner++;
}

std::cout << std::endl;
return 0;

}

Val and Var in Kotlin

In Kotlin we use var to declare a variable. It is mutable. We can change, reassign variables. Example,

fun main(args : Array<String>){
    var x = 10
    println(x)

    x = 100 // vars can reassign.
    println(x)
}

We use val to declare constants. They are immutable. Unable to change, reassign vals. val is something similar to final variables in java. Example,

fun main(args : Array<String>){
    val y = 10
    println(y)

    y = 100 // vals can't reassign (COMPILE ERROR!).
    println(y)
}

How do I filter ForeignKey choices in a Django ModelForm?

ForeignKey is represented by django.forms.ModelChoiceField, which is a ChoiceField whose choices are a model QuerySet. See the reference for ModelChoiceField.

So, provide a QuerySet to the field's queryset attribute. Depends on how your form is built. If you build an explicit form, you'll have fields named directly.

form.rate.queryset = Rate.objects.filter(company_id=the_company.id)

If you take the default ModelForm object, form.fields["rate"].queryset = ...

This is done explicitly in the view. No hacking around.

What is the difference between substr and substring?

substring(startIndex, endIndex(not included))

substr(startIndex, how many characters)

const string = 'JavaScript';

console.log('substring(1,2)', string.substring(1,2)); // a
console.log('substr(1,2)', string.substr(1,2)); // av

Credit card payment gateway in PHP?

Braintree also has an open source PHP library that makes PHP integration pretty easy.

node: command not found

The problem is that your PATH does not include the location of the node executable.

You can likely run node as "/usr/local/bin/node".

You can add that location to your path by running the following command to add a single line to your bashrc file:

echo 'export PATH=$PATH:/usr/local/bin' >> $HOME/.bashrc

How can I count the number of elements of a given value in a matrix?

Use nnz instead of sum. No need for the double call to collapse matrices to vectors and it is likely faster than sum.

nnz(your_matrix == 5)

Doc

Start ssh-agent on login

Tried couple solutions from many sources but all seemed like too much trouble. Finally I found the easiest one :)

If you're not yet familiar with zsh and oh-my-zsh then install it. You will love it :)

Then edit .zshrc

vim ~/.zshrc

find plugins section and update it to use ssh-agent like so:

plugins=(ssh-agent git)

And that's all! You'll have ssh-agent up and running every time you start your shell

Change color of Label in C#

You can try this with Color.FromArgb:

Random rnd = new Random();
lbl.ForeColor = Color.FromArgb(rnd.Next(255), rnd.Next(255), rnd.Next(255));

Difference between Visual Basic 6.0 and VBA

It's VBA. VBA means Visual Basic for Applications, and it is used for macros on Office documents. It doesn't have access to VB.NET features, so it's more like a modified version of VB6, with add-ons to be able to work on the document (like Worksheet in VBA for Excel).

Rerender view on browser resize with React

Had to bind it to 'this' in the constructor to get it working with Class syntax

class MyComponent extends React.Component {
  constructor(props) {
    super(props)
    this.resize = this.resize.bind(this)      
  }
  componentDidMount() {
    window.addEventListener('resize', this.resize)
  }
  componentWillUnmount() {
    window.removeEventListener('resize', this.resize)
  }
}

Fitting iframe inside a div

I think I may have a better solution for having a fully responsive iframe (a vimeo video in my case) embed on your site. Nest the iframe in a div. Give them the following styles:

div {
    width: 100%;
    height: 0;
    padding-bottom: 56%; /* Change this till it fits the dimensions of your video */
    position: relative;
}

div iframe {
    width: 100%;
    height: 100%;
    position: absolute;
    display: block;
    top: 0;
    left: 0;
}

Just did it now for a client, and it seems to be working: http://themilkrunsa.co.za/

What is a provisioning profile used for when developing iPhone applications?

A Quote from : iPhone Developer Program (~8MB PDF)

A provisioning profile is a collection of digital entities that uniquely ties developers and devices to an authorized iPhone Development Team and enables a device to be used for testing. A Development Provisioning Profile must be installed on each device on which you wish to run your application code. Each Development Provisioning Profile will contain a set of iPhone Development Certificates, Unique Device Identifiers and an App ID. Devices specified within the provisioning profile can be used for testing only by those individuals whose iPhone Development Certificates are included in the profile. A single device can contain multiple provisioning profiles.

how to make log4j to write to the console as well

Write the root logger as below for logging on both console and FILE

log4j.rootLogger=ERROR,console,FILE

And write the respective definitions like Target, Layout, and ConversionPattern (MaxFileSize for file etc).

PHP - Merging two arrays into one array (also Remove Duplicates)

As already mentioned, array_unique() could be used, but only when dealing with simple data. The objects are not so simple to handle.

When php tries to merge the arrays, it tries to compare the values of the array members. If a member is an object, it cannot get its value and uses the spl hash instead. Read more about spl_object_hash here.

Simply told if you have two objects, instances of the very same class and if one of them is not a reference to the other one - you will end up having two objects, no matter the value of their properties.

To be sure that you don't have any duplicates within the merged array, Imho you should handle the case on your own.

Also if you are going to merge multidimensional arrays, consider using array_merge_recursive() over array_merge().

Redis - Connect to Remote Server

  • if you downloaded redis yourself (not apt-get install redis-server) and then edited the redis.conf with the above suggestions, make sure your start redis with the config like so: ./src/redis-server redis.conf

    • also side note i am including a screenshot of virtual box setting to connect to redis, if you are on windows and connecting to a virtualbox vm.

enter image description here

Proxy setting for R

On Mac OS, I found the best solution here. Quoting the author, two simple steps are:

1) Open Terminal and do the following:

export http_proxy=http://staff-proxy.ul.ie:8080
export HTTP_PROXY=http://staff-proxy.ul.ie:8080

2) Run R and do the following:

Sys.setenv(http_proxy="http://staff-proxy.ul.ie:8080")

double-check this with:

Sys.getenv("http_proxy")

I am behind university proxy, and this solution worked perfectly. The major issue is to export the items in Terminal before running R, both in upper- and lower-case.

Quickest way to compare two generic lists for differences

I have used this code to compare two list which has million of records.

This method will not take much time

    //Method to compare two list of string
    private List<string> Contains(List<string> list1, List<string> list2)
    {
        List<string> result = new List<string>();

        result.AddRange(list1.Except(list2, StringComparer.OrdinalIgnoreCase));
        result.AddRange(list2.Except(list1, StringComparer.OrdinalIgnoreCase));

        return result;
    }

Spring Boot application.properties value not populating

The user "geoand" is right in pointing out the reasons here and giving a solution. But a better approach is to encapsulate your configuration into a separate class, say SystemContiguration java class and then inject this class into what ever services you want to use those fields.

Your current way(@grahamrb) of reading config values directly into services is error prone and would cause refactoring headaches if config setting name is changed.

Correct way to load a Nib for a UIView subclass

Well you could either initialize the xib using a view controller and use viewController.view. or do it the way you did it. Only making a UIView subclass as the controller for UIView is a bad idea.

If you don't have any outlets from your custom view then you can directly use a UIViewController class to initialize it.

Update: In your case:

UIViewController *genericViewCon = [[UIViewController alloc] initWithNibName:@"CustomView"];
//Assuming you have a reference for the activity indicator in your custom view class
CustomView *myView = (CustomView *)genericViewCon.view;
[parentView addSubview:myView];
//And when necessary
[myView.activityIndicator startAnimating]; //or stop

Otherwise you have to make a custom UIViewController(to make it as the file's owner so that the outlets are properly wired up).

YourCustomController *yCustCon = [[YourCustomController alloc] initWithNibName:@"YourXibName"].

Wherever you want to add the view you can use.

[parentView addSubview:yCustCon.view];

However passing the another view controller(already being used for another view) as the owner while loading the xib is not a good idea as the view property of the controller will be changed and when you want to access the original view, you won't have a reference to it.

EDIT: You will face this problem if you have setup your new xib with file's owner as the same main UIViewController class and tied the view property to the new xib view.

i.e;

  • YourMainViewController -- manages -- mainView
  • CustomView -- needs to load from xib as and when required.

The below code will cause confusion later on, if you write it inside view did load of YourMainViewController. That is because self.view from this point on will refer to your customview

-(void)viewDidLoad:(){
  UIView *childView= [[[NSBundle mainBundle] loadNibNamed:@"YourXibName" owner:self options:nil] objectAtIndex:0];
}

Data access object (DAO) in Java

DAO (Data Access Object) is a very used design pattern in enterprise applications. It basically is the module that is used to access data from every source (DBMS, XML and so on). I suggest you to read some examples, like this one:

DAO Example

Please note that there are different ways to implements the original DAO Pattern, and there are many frameworks that can simplify your work. For example, the ORM (Object Relational Mapping) frameworks like iBatis or Hibernate, are used to map the result of SQL queries to java objects.

Hope it helps, Bye!

Writing File to Temp Folder

You can dynamically retrieve a temp path using as following and better to use it instead of using hard coded string value for temp location.It will return the temp folder or temp file as you want.

string filePath = Path.Combine(Path.GetTempPath(),"SaveFile.txt");

or

Path.GetTempFileName();

How to capture and save an image using custom camera in Android?

 showbookimage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                // create intent with ACTION_IMAGE_CAPTURE action
                Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                /**
 Here REQUEST_IMAGE is the unique integer value you can pass it any integer
 **/
                // start camera activity
                startActivityForResult(intent, TAKE_PICTURE);
            }

            }

        );

then u can now give the image a file name as follows and then convert it into bitmap and later on to file

 private void createImageFile(Bitmap bitmap) throws IOException {
        // Create an image file name
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        File image = File.createTempFile(
                imageFileName,  /* prefix */
                ".jpg",         /* suffix */
                storageDir      /* directory */
        );
        FileOutputStream stream = new FileOutputStream(image);
        stream.write(bytes.toByteArray());
        stream.close();
        // Save a file: path for use with ACTION_VIEW intents
        mCurrentPhotoPath = "file:" + image.getAbsolutePath();
        fileUri = image.getAbsolutePath();
        Picasso.with(getActivity()).load(image).into(showbookimage);
    }
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {

        if (requestCode == TAKE_PICTURE && resultCode== Activity.RESULT_OK && intent != null){
            // get bundle
            Bundle extras = intent.getExtras();
            // get
            bitMap = (Bitmap) extras.get("data");
//            showbookimage.setImageBitmap(bitMap);
            try {
                createImageFile(bitMap);
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

use picasso for images to display rather fast

How to print a dictionary line by line in Python?

Here is my solution to the problem. I think it's similar in approach, but a little simpler than some of the other answers. It also allows for an arbitrary number of sub-dictionaries and seems to work for any datatype (I even tested it on a dictionary which had functions as values):

def pprint(web, level):
    for k,v in web.items():
        if isinstance(v, dict):
            print('\t'*level, f'{k}: ')
            level += 1
            pprint(v, level)
            level -= 1
        else:
            print('\t'*level, k, ": ", v)

Spark: Add column to dataframe conditionally

My bad, I had missed one part of the question.

Best, cleanest way is to use a UDF. Explanation within the code.

// create some example data...BY DataFrame
// note, third record has an empty string
case class Stuff(a:String,b:Int)
val d= sc.parallelize(Seq( ("a",1),("b",2),
     ("",3) ,("d",4)).map { x => Stuff(x._1,x._2)  }).toDF

// now the good stuff.
import org.apache.spark.sql.functions.udf
// function that returns 0 is string empty 
val func = udf( (s:String) => if(s.isEmpty) 0 else 1 )
// create new dataframe with added column named "notempty"
val r = d.select( $"a", $"b", func($"a").as("notempty") )

    scala> r.show
+---+---+--------+
|  a|  b|notempty|
+---+---+--------+
|  a|  1|    1111|
|  b|  2|    1111|
|   |  3|       0|
|  d|  4|    1111|
+---+---+--------+

jQuery getTime function

@nickf's correct. However, to be a little more precise:

// if you try to print it, it will return something like:
// Sat Mar 21 2009 20:13:07 GMT-0400 (Eastern Daylight Time)
// This time comes from the user's machine.
var myDate = new Date();

So if you want to display it as mm/dd/yyyy, you would do this:

var displayDate = (myDate.getMonth()+1) + '/' + (myDate.getDate()) + '/' + myDate.getFullYear();

Check out the full reference of the Date object. Unfortunately it is not nearly as nice to print out various formats as it is with other server-side languages. For this reason there-are-many-functions available in the wild.

The multi-part identifier could not be bound

This error can also be caused by simply missing a comma , between the column names in the SELECT statement.

eg:

SELECT MyCol1, MyCol2 MyCol3 FROM SomeTable;

How to diff a commit with its parent?

Use:

git diff 15dc8^!

as described in the following fragment of git-rev-parse(1) manpage (or in modern git gitrevisions(7) manpage):

Two other shorthands for naming a set that is formed by a commit and its parent commits exist. The r1^@ notation means all parents of r1. r1^! includes commit r1 but excludes all of its parents.

This means that you can use 15dc8^! as a shorthand for 15dc8^..15dc8 anywhere in git where revisions are needed. For diff command the git diff 15dc8^..15dc8 is understood as git diff 15dc8^ 15dc8, which means the difference between parent of commit (15dc8^) and commit (15dc8).

Note: the description in git-rev-parse(1) manpage talks about revision ranges, where it needs to work also for merge commits, with more than one parent. Then r1^! is "r1 --not r1^@" i.e. "r1 ^r1^1 ^r1^2 ..."


Also, you can use git show COMMIT to get commit description and diff for a commit. If you want only diff, you can use git diff-tree -p COMMIT

overlay two images in android to set an imageview

Its a bit late answer, but it covers merging images from urls using Picasso

MergeImageView

import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Build;
import android.util.AttributeSet;
import android.util.SparseArray;
import android.widget.ImageView;
import com.squareup.picasso.Picasso;

import java.io.IOException;
import java.util.List;

public class MergeImageView extends ImageView {

    private SparseArray<Bitmap> bitmaps = new SparseArray<>();
    private Picasso picasso;
    private final int DEFAULT_IMAGE_SIZE = 50;
    private int MIN_IMAGE_SIZE = DEFAULT_IMAGE_SIZE;
    private int MAX_WIDTH = DEFAULT_IMAGE_SIZE * 2, MAX_HEIGHT = DEFAULT_IMAGE_SIZE * 2;
    private String picassoRequestTag = null;

    public MergeImageView(Context context) {
        super(context);
    }

    public MergeImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MergeImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public MergeImageView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public boolean isInEditMode() {
        return true;
    }

    public void clearResources() {
        if (bitmaps != null) {
            for (int i = 0; i < bitmaps.size(); i++)
                bitmaps.get(i).recycle();
            bitmaps.clear();
        }
        // cancel picasso requests
        if (picasso != null && AppUtils.ifNotNullEmpty(picassoRequestTag))
            picasso.cancelTag(picassoRequestTag);
        picasso = null;
        bitmaps = null;
    }

    public void createMergedBitmap(Context context, List<String> imageUrls, String picassoTag) {
        picasso = Picasso.with(context);
        int count = imageUrls.size();
        picassoRequestTag = picassoTag;

        boolean isEven = count % 2 == 0;
        // if url size are not even make MIN_IMAGE_SIZE even
        MIN_IMAGE_SIZE = DEFAULT_IMAGE_SIZE + (isEven ? count / 2 : (count / 2) + 1);
        // set MAX_WIDTH and MAX_HEIGHT to twice of MIN_IMAGE_SIZE
        MAX_WIDTH = MAX_HEIGHT = MIN_IMAGE_SIZE * 2;
        // in case of odd urls increase MAX_HEIGHT
        if (!isEven) MAX_HEIGHT = MAX_WIDTH + MIN_IMAGE_SIZE;

        // create default bitmap
        Bitmap bitmap = Bitmap.createScaledBitmap(BitmapFactory.decodeResource(context.getResources(), R.drawable.ic_wallpaper),
                MIN_IMAGE_SIZE, MIN_IMAGE_SIZE, false);

        // change default height (wrap_content) to MAX_HEIGHT
        int height = Math.round(AppUtils.convertDpToPixel(MAX_HEIGHT, context));
        setMinimumHeight(height * 2);

        // start AsyncTask
        for (int index = 0; index < count; index++) {
            // put default bitmap as a place holder
            bitmaps.put(index, bitmap);
            new PicassoLoadImage(index, imageUrls.get(index)).execute();
            // if you want parallel execution use
            // new PicassoLoadImage(index, imageUrls.get(index)).(AsyncTask.THREAD_POOL_EXECUTOR);
        }
    }

    private class PicassoLoadImage extends AsyncTask<String, Void, Bitmap> {

        private int index = 0;
        private String url;

        PicassoLoadImage(int index, String url) {
            this.index = index;
            this.url = url;
        }

        @Override
        protected Bitmap doInBackground(String... params) {
            try {
                // synchronous picasso call
                return picasso.load(url).resize(MIN_IMAGE_SIZE, MIN_IMAGE_SIZE).tag(picassoRequestTag).get();
            } catch (IOException e) {
            }
            return null;
        }

        @Override
        protected void onPostExecute(Bitmap output) {
            super.onPostExecute(output);
            if (output != null)
                bitmaps.put(index, output);

            // create canvas
            Bitmap.Config conf = Bitmap.Config.RGB_565;
            Bitmap canvasBitmap = Bitmap.createBitmap(MAX_WIDTH, MAX_HEIGHT, conf);
            Canvas canvas = new Canvas(canvasBitmap);
            canvas.drawColor(Color.WHITE);

            // if height and width are equal we have even images
            boolean isEven = MAX_HEIGHT == MAX_WIDTH;
            int imageSize = bitmaps.size();
            int count = imageSize;

            // we have odd images
            if (!isEven) count = imageSize - 1;
            for (int i = 0; i < count; i++) {
                Bitmap bitmap = bitmaps.get(i);
                canvas.drawBitmap(bitmap, bitmap.getWidth() * (i % 2), bitmap.getHeight() * (i / 2), null);
            }
            // if images are not even set last image width to MAX_WIDTH
            if (!isEven) {
                Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmaps.get(count), MAX_WIDTH, MIN_IMAGE_SIZE, false);
                canvas.drawBitmap(scaledBitmap, scaledBitmap.getWidth() * (count % 2), scaledBitmap.getHeight() * (count / 2), null);
            }
            // set bitmap
            setImageBitmap(canvasBitmap);
        }
    }
}

xml

<com.example.MergeImageView
    android:id="@+id/iv_thumb"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

Example

List<String> urls = new ArrayList<>();
String picassoTag = null;
// add your urls
((MergeImageView)findViewById(R.id.iv_thumb)).
        createMergedBitmap(MainActivity.this, urls,picassoTag);

How can I solve Exception in thread "main" java.lang.NullPointerException error

This is the problem

double a[] = null;

Since a is null, NullPointerException will arise every time you use it until you initialize it. So this:

a[i] = var;

will fail.

A possible solution would be initialize it when declaring it:

double a[] = new double[PUT_A_LENGTH_HERE]; //seems like this constant should be 7

IMO more important than solving this exception, is the fact that you should learn to read the stacktrace and understand what it says, so you could detect the problems and solve it.

java.lang.NullPointerException

This exception means there's a variable with null value being used. How to solve? Just make sure the variable is not null before being used.

at twoten.TwoTenB.(TwoTenB.java:29)

This line has two parts:

  • First, shows the class and method where the error was thrown. In this case, it was at <init> method in class TwoTenB declared in package twoten. When you encounter an error message with SomeClassName.<init>, means the error was thrown while creating a new instance of the class e.g. executing the constructor (in this case that seems to be the problem).
  • Secondly, shows the file and line number location where the error is thrown, which is between parenthesis. This way is easier to spot where the error arose. So you have to look into file TwoTenB.java, line number 29. This seems to be a[i] = var;.

From this line, other lines will be similar to tell you where the error arose. So when reading this:

at javapractice.JavaPractice.main(JavaPractice.java:32)

It means that you were trying to instantiate a TwoTenB object reference inside the main method of your class JavaPractice declared in javapractice package.

Swift Alamofire: How to get the HTTP response status code

For Swift 2.0 users with Alamofire > 2.0

Alamofire.request(.GET, url)
  .responseString { _, response, result in
    if response?.statusCode == 200{
      //Do something with result
    }
}

Share Text on Facebook from Android App via ACTION_SEND

Check this out : By this we can check activity results also....
// Open all sharing option for user
                    Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND); 
                    sharingIntent.setType("text/plain");                    
                    sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, ShortDesc+" from "+BusinessName);
                    sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, ShortDesc+" "+ShareURL);
                    sharingIntent.putExtra(Intent.EXTRA_TITLE, ShortDesc+" "+ShareURL);
                    startActivityForResult(Intent.createChooser(sharingIntent, "Share via"),1000);
/**
     * Get the result when we share any data to another activity 
     * */
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch(requestCode) {
        case 1000:
            if(resultCode == RESULT_OK)
                Toast.makeText(getApplicationContext(), "Activity 1 returned OK", Toast.LENGTH_LONG).show();
            else
                Toast.makeText(getApplicationContext(), "Activity 1 returned NOT OK", Toast.LENGTH_LONG).show();
            break;
        case 1002:
            if(resultCode == RESULT_OK)
                Toast.makeText(getApplicationContext(), "Activity 2 returned OK", Toast.LENGTH_LONG).show();
            break;
        }// end switch



    }// end onActivityResult

Compare two folders which has many files inside contents

To get summary of new/missing files, and which files differ:

diff -arq folder1 folder2

a treats all files as text, r recursively searched subdirectories, q reports 'briefly', only when files differ

Getting user input

Use the raw_input() function to get input from users (2.x):

print "Enter a file name:",
filename = raw_input()

or just:

filename = raw_input('Enter a file name: ')

or if in Python 3.x:

filename = input('Enter a file name: ')

How do I copy an object in Java?

Yes. You need to Deep Copy your object.

Select2() is not a function

Put config.assets.debug = false in config/environments/development.rb.

Writing to an Excel spreadsheet

import xlwt

def output(filename, sheet, list1, list2, x, y, z):
    book = xlwt.Workbook()
    sh = book.add_sheet(sheet)

    variables = [x, y, z]
    x_desc = 'Display'
    y_desc = 'Dominance'
    z_desc = 'Test'
    desc = [x_desc, y_desc, z_desc]

    col1_name = 'Stimulus Time'
    col2_name = 'Reaction Time'

    #You may need to group the variables together
    #for n, (v_desc, v) in enumerate(zip(desc, variables)):
    for n, v_desc, v in enumerate(zip(desc, variables)):
        sh.write(n, 0, v_desc)
        sh.write(n, 1, v)

    n+=1

    sh.write(n, 0, col1_name)
    sh.write(n, 1, col2_name)

    for m, e1 in enumerate(list1, n+1):
        sh.write(m, 0, e1)

    for m, e2 in enumerate(list2, n+1):
        sh.write(m, 1, e2)

    book.save(filename)

for more explanation: https://github.com/python-excel

Python Pandas: Get index of rows which column matches certain value

I extended this question that is how to gets the row, columnand value of all matches value?

here is solution:

import pandas as pd
import numpy as np


def search_coordinate(df_data: pd.DataFrame, search_set: set) -> list:
    nda_values = df_data.values
    tuple_index = np.where(np.isin(nda_values, [e for e in search_set]))
    return [(row, col, nda_values[row][col]) for row, col in zip(tuple_index[0], tuple_index[1])]


if __name__ == '__main__':
    test_datas = [['cat', 'dog', ''],
                  ['goldfish', '', 'kitten'],
                  ['Puppy', 'hamster', 'mouse']
                  ]
    df_data = pd.DataFrame(test_datas)
    print(df_data)
    result_list = search_coordinate(df_data, {'dog', 'Puppy'})
    print(f"\n\n{'row':<4} {'col':<4} {'name':>10}")
    [print(f"{row:<4} {col:<4} {name:>10}") for row, col, name in result_list]

Output:

          0        1       2
0       cat      dog        
1  goldfish           kitten
2     Puppy  hamster   mouse


row  col        name
0    1           dog
2    0         Puppy

How do I configure PyCharm to run py.test tests?

With a special Conda python setup which included the pip install for py.test plus usage of the Specs addin (option --spec) (for Rspec like nice test summary language), I had to do ;

1.Edit the default py.test to include option= --spec , which means use the plugin: https://github.com/pchomik/pytest-spec

2.Create new test configuration, using py.test. Change its python interpreter to use ~/anaconda/envs/ your choice of interpreters, eg py27 for my namings.

3.Delete the 'unittests' test configuration.

4.Now the default test config is py.test with my lovely Rspec style outputs. I love it! Thank you everyone!

p.s. Jetbrains' doc on run/debug configs is here: https://www.jetbrains.com/help/pycharm/2016.1/run-debug-configuration-py-test.html?search=py.test

Cosine Similarity between 2 Number Lists

import math
from itertools import izip

def dot_product(v1, v2):
    return sum(map(lambda x: x[0] * x[1], izip(v1, v2)))

def cosine_measure(v1, v2):
    prod = dot_product(v1, v2)
    len1 = math.sqrt(dot_product(v1, v1))
    len2 = math.sqrt(dot_product(v2, v2))
    return prod / (len1 * len2)

You can round it after computing:

cosine = format(round(cosine_measure(v1, v2), 3))

If you want it really short, you can use this one-liner:

from math import sqrt
from itertools import izip

def cosine_measure(v1, v2):
    return (lambda (x, y, z): x / sqrt(y * z))(reduce(lambda x, y: (x[0] + y[0] * y[1], x[1] + y[0]**2, x[2] + y[1]**2), izip(v1, v2), (0, 0, 0)))

Static variables in C++

Static variable in a header file:

say 'common.h' has

static int zzz;

This variable 'zzz' has internal linkage (This same variable can not be accessed in other translation units). Each translation unit which includes 'common.h' has it's own unique object of name 'zzz'.

Static variable in a class:

Static variable in a class is not a part of the subobject of the class. There is only one copy of a static data member shared by all the objects of the class.

$9.4.2/6 - "Static data members of a class in namespace scope have external linkage (3.5).A local class shall not have static data members."

So let's say 'myclass.h' has

struct myclass{
   static int zzz;        // this is only a declaration
};

and myclass.cpp has

#include "myclass.h"

int myclass::zzz = 0           // this is a definition, 
                               // should be done once and only once

and "hisclass.cpp" has

#include "myclass.h"

void f(){myclass::zzz = 2;}    // myclass::zzz is always the same in any 
                               // translation unit

and "ourclass.cpp" has

#include "myclass.h"
void g(){myclass::zzz = 2;}    // myclass::zzz is always the same in any 
                               // translation unit

So, class static members are not limited to only 2 translation units. They need to be defined only once in any one of the translation units.

Note: usage of 'static' to declare file scope variable is deprecated and unnamed namespace is a superior alternate

how to configure hibernate config file for sql server

Keep the jar files under web-inf lib incase you included jar and it is not able to identify .

It worked in my case where everything was ok but it was not able to load the driver class.

How do I enable php to work with postgresql?

You need to isntall pdo_pgsql package

slf4j: how to log formatted message, object array, exception

As of SLF4J 1.6.0, in the presence of multiple parameters and if the last argument in a logging statement is an exception, then SLF4J will presume that the user wants the last argument to be treated as an exception and not a simple parameter. See also the relevant FAQ entry.

So, writing (in SLF4J version 1.7.x and later)

 logger.error("one two three: {} {} {}", "a", "b", 
              "c", new Exception("something went wrong"));

or writing (in SLF4J version 1.6.x)

 logger.error("one two three: {} {} {}", new Object[] {"a", "b", 
              "c", new Exception("something went wrong")});

will yield

one two three: a b c
java.lang.Exception: something went wrong
    at Example.main(Example.java:13)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at ...

The exact output will depend on the underlying framework (e.g. logback, log4j, etc) as well on how the underlying framework is configured. However, if the last parameter is an exception it will be interpreted as such regardless of the underlying framework.

How do I get the path of the Python script I am running in?

import os
print os.path.abspath(__file__)

How do you execute SQL from within a bash script?

If you do not want to install sqlplus on your server/machine then the following command-line tool can be your friend. It is a simple Java application, only Java 8 that you need in order to you can execute this tool.

The tool can be used to run any SQL from the Linux bash or Windows command line.

Example:

java -jar sql-runner-0.2.0-with-dependencies.jar \
     -j jdbc:oracle:thin:@//oracle-db:1521/ORCLPDB1.localdomain \
     -U "SYS as SYSDBA" \
     -P Oradoc_db1 \
      "select 1 from dual"

Documentation is here.

You can download the binary file from here.

xcopy file, rename, suppress "Does xxx specify a file name..." message

XCOPY with * at the end of the target to copy files whether they exist or not in destination XCOPY with \ at the end of the target to copy folders and contents whether exist or not in destination

Alternatively

RoboForm SOURCE DEST FILE for files RoboForm SOURCE DEST for folders

How do I use a regex in a shell script?

To complement the existing helpful answers:

Using Bash's own regex-matching operator, =~, is a faster alternative in this case, given that you're only matching a single value already stored in a variable:

set -- '12-34-5678' # set $1 to sample value

kREGEX_DATE='^[0-9]{2}[-/][0-9]{2}[-/][0-9]{4}$' # note use of [0-9] to avoid \d
[[ $1 =~ $kREGEX_DATE ]]
echo $? # 0 with the sample value, i.e., a successful match

Note, however, that the caveat re using flavor-specific regex constructs such as \d equally applies: While =~ supports EREs (extended regular expressions), it also supports the host platform's specific extension - it's a rare case of Bash's behavior being platform-dependent.

To remain portable (in the context of Bash), stick to the POSIX ERE specification.

Note that =~ even allows you to define capture groups (parenthesized subexpressions) whose matches you can later access through Bash's special ${BASH_REMATCH[@]} array variable.

Further notes:

  • $kREGEX_DATE is used unquoted, which is necessary for the regex to be recognized as such (quoted parts would be treated as literals).

  • While not always necessary, it is advisable to store the regex in a variable first, because Bash has trouble with regex literals containing \.

    • E.g., on Linux, where \< is supported to match word boundaries, [[ 3 =~ \<3 ]] && echo yes doesn't work, but re='\<3'; [[ 3 =~ $re ]] && echo yes does.
  • I've changed variable name REGEX_DATE to kREGEX_DATE (k signaling a (conceptual) constant), so as to ensure that the name isn't an all-uppercase name, because all-uppercase variable names should be avoided to prevent conflicts with special environment and shell variables.

Case insensitive regular expression without re.compile?

The case-insensitive marker, (?i) can be incorporated directly into the regex pattern:

>>> import re
>>> s = 'This is one Test, another TEST, and another test.'
>>> re.findall('(?i)test', s)
['Test', 'TEST', 'test']

How do I get a string format of the current date time, in python?

You can use the datetime module for working with dates and times in Python. The strftime method allows you to produce string representation of dates and times with a format you specify.

>>> import datetime
>>> datetime.date.today().strftime("%B %d, %Y")
'July 23, 2010'
>>> datetime.datetime.now().strftime("%I:%M%p on %B %d, %Y")
'10:36AM on July 23, 2010'

Fatal error: Call to undefined function socket_create()

Follow these steps if you're on openSuse or SUSE.

Install php7 if it's not already installed.

zypper in php7

If you have php7 installed, update it with:

zypper update php7

Install php7-sockets

zypper in php7-sockets

How to vertically center a <span> inside a div?

As in a similar question, use display: inline-block with a placeholder element to vertically center the span inside of a block element:

_x000D_
_x000D_
html, body, #container, #placeholder { height: 100%; }_x000D_
_x000D_
#content, #placeholder { display:inline-block; vertical-align: middle; }
_x000D_
<!doctype html>_x000D_
<html lang="en">_x000D_
  <head>_x000D_
  </head>_x000D_
_x000D_
  <body>_x000D_
    <div id="container">_x000D_
      <span id="content">_x000D_
        Content_x000D_
      </span>_x000D_
      <span id="placeholder"></span>_x000D_
    </div>_x000D_
  </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Vertical alignment is only applied to inline elements or table cells, so use it along with display:inline-block or display:table-cell with a display:table parent when vertically centering block elements.

References:

CSS Horizontal and Vertical Centering

Execute php file from another php

exec is shelling to the operating system, and unless the OS has some special way of knowing how to execute a file, then it's going to default to treating it as a shell script or similar. In this case, it has no idea how to run your php file. If this script absolutely has to be executed from a shell, then either execute php passing the filename as a parameter, e.g

exec ('/usr/local/bin/php -f /opt/lampp/htdocs/.../name.php)') ;

or use the punct at the top of your php script

#!/usr/local/bin/php
<?php ... ?>

How do I copy the contents of a String to the clipboard in C#?

Using the solution showed in this question, System.Windows.Forms.Clipboard.SetText(...), results in the exception:

Current thread must be set to single thread apartment (STA) mode before OLE calls can be made

To prevent this, you can add the attribute:

[STAThread]

to

static void Main(string[] args)

.NET data structures: ArrayList, List, HashTable, Dictionary, SortedList, SortedDictionary -- Speed, memory, and when to use each?

First, all collections in .NET implement IEnumerable.

Second, a lot of the collections are duplicates because generics were added in version 2.0 of the framework.

So, although the generic collections likely add features, for the most part:

  • List is a generic implementation of ArrayList.
  • Dictionary is a generic implementation of Hashtable

Arrays are a fixed size collection that you can change the value stored at a given index.

SortedDictionary is an IDictionary that is sorted based on the keys. SortedList is an IDictionary that is sorted based on a required IComparer.

So, the IDictionary implementations (those supporting KeyValuePairs) are: * Hashtable * Dictionary * SortedList * SortedDictionary

Another collection that was added in .NET 3.5 is the Hashset. It is a collection that supports set operations.

Also, the LinkedList is a standard linked-list implementation (the List is an array-list for faster retrieval).

Lodash remove duplicates from array

Or simply Use union, for simple array.

_.union([1,2,3,3], [3,5])

// [1,2,3,5]

The given key was not present in the dictionary. Which key?

string Value = dic.ContainsKey("Name") ? dic["Name"] : "Required Name"

With this code, we will get string data in 'Value'. If key 'Name' exists in the dictionary 'dic' then fetch this value, else returns "Required Name" string.

How to solve the system.data.sqlclient.sqlexception (0x80131904) error

You also need to change the DataSource of the connection string. KELVIN-PC is the name of your local machine and the sql server is running on the default instance.

If you are sure the the server is running as the default instance, you can always use . in the DataSource, eg.

connectionString="Data Source=.;Initial Catalog=LMS;User ID=sa;Password=temperament"

otherwise, you need to specify the name of the instance of the server,

connectionString="Data Source=.\INSTANCENAME;Initial Catalog=LMS;User ID=sa;Password=temperament"

How to import CSV file data into a PostgreSQL table?

Use this SQL code

    copy table_name(atribute1,attribute2,attribute3...)
    from 'E:\test.csv' delimiter ',' csv header

the header keyword lets the DBMS know that the csv file have a header with attributes

for more visit http://www.postgresqltutorial.com/import-csv-file-into-posgresql-table/

Clone() vs Copy constructor- which is recommended in java

Keep in mind that the copy constructor limits the class type to that of the copy constructor. Consider the example:

// Need to clone person, which is type Person
Person clone = new Person(person);

This doesn't work if person could be a subclass of Person (or if Person is an interface). This is the whole point of clone, is that it can can clone the proper type dynamically at runtime (assuming clone is properly implemented).

Person clone = (Person)person.clone();

or

Person clone = (Person)SomeCloneUtil.clone(person); // See Bozho's answer

Now person can be any type of Person assuming that clone is properly implemented.

Is there a way to programmatically minimize a window

FormName.WindowState = FormWindowState.Minimized;

Adding new column to existing DataFrame in Python pandas

This is the simple way of adding a new column: df['e'] = e

Print in new line, java

You should use the built in line separator. The advantage is that you don't have to concern what system you code is running on, it will just work.

Since Java 1.7

System.lineSeparator()

Pre Java 1.7

System.getProperty("line.separator")

SQL Developer is returning only the date, not the time. How do I fix this?

To expand on some of the previous answers, I found that Oracle DATE objects behave different from Oracle TIMESTAMP objects. In particular, if you set your NLS_DATE_FORMAT to include fractional seconds, the entire time portion is omitted.

  • Format "YYYY-MM-DD HH24:MI:SS" works as expected, for DATE and TIMESTAMP
  • Format "YYYY-MM-DD HH24:MI:SSXFF" displays just the date portion for DATE, works as expected for TIMESTAMP

My personal preference is to set DATE to "YYYY-MM-DD HH24:MI:SS", and to set TIMESTAMP to "YYYY-MM-DD HH24:MI:SSXFF".

PHP, How to get current date in certain format

date("Y-m-d H:i:s"); // This should do it.

Is there a no-duplicate List implementation out there?

So here's what I did eventually. I hope this helps someone else.

class NoDuplicatesList<E> extends LinkedList<E> {
    @Override
    public boolean add(E e) {
        if (this.contains(e)) {
            return false;
        }
        else {
            return super.add(e);
        }
    }

    @Override
    public boolean addAll(Collection<? extends E> collection) {
        Collection<E> copy = new LinkedList<E>(collection);
        copy.removeAll(this);
        return super.addAll(copy);
    }

    @Override
    public boolean addAll(int index, Collection<? extends E> collection) {
        Collection<E> copy = new LinkedList<E>(collection);
        copy.removeAll(this);
        return super.addAll(index, copy);
    }

    @Override
    public void add(int index, E element) {
        if (this.contains(element)) {
            return;
        }
        else {
            super.add(index, element);
        }
    }
}   

Right way to convert data.frame to a numeric matrix, when df also contains strings?

Another way of doing it is by using the read.table() argument colClasses to specify the column type by making colClasses=c(*column class types*). If there are 6 columns whose members you want as numeric, you need to repeat the character string "numeric" six times separated by commas, importing the data frame, and as.matrix() the data frame. P.S. looks like you have headers, so I put header=T.

as.matrix(read.table(SFI.matrix,header=T,
colClasses=c("numeric","numeric","numeric","numeric","numeric","numeric"),
sep=","))

rejected master -> master (non-fast-forward)

I've just received this error.

I created a github repository after creating my local git repository so I needed to accept the changes into local before pushing to github. In this case the only change was the readme file created as optional step when creating github repository.

git pull https://github.com/*username*/*repository*.git master

repository URL is got from here on project github page :

enter image description here

I then re-initialised (this may not be needed)

git init
git add .
git commit -m "update"

Then push :

git push

PHP namespaces and "use"

The use operator is for giving aliases to names of classes, interfaces or other namespaces. Most use statements refer to a namespace or class that you'd like to shorten:

use My\Full\Namespace;

is equivalent to:

use My\Full\Namespace as Namespace;
// Namespace\Foo is now shorthand for My\Full\Namespace\Foo

If the use operator is used with a class or interface name, it has the following uses:

// after this, "new DifferentName();" would instantiate a My\Full\Classname
use My\Full\Classname as DifferentName;

// global class - making "new ArrayObject()" and "new \ArrayObject()" equivalent
use ArrayObject;

The use operator is not to be confused with autoloading. A class is autoloaded (negating the need for include) by registering an autoloader (e.g. with spl_autoload_register). You might want to read PSR-4 to see a suitable autoloader implementation.

How to easily map c++ enums to strings

I recently had the same issue with a vendor library (Fincad). Fortunately, the vendor provided xml doucumentation for all the enums. I ended up generating a map for each enum type and providing a lookup function for each enum. This technique also allows you to intercept a lookup outside the range of the enum.

I'm sure swig could do something similar for you, but I'm happy to provide the code generation utils which are written in ruby.

Here is a sample of the code:

std::map<std::string, switches::FCSW2::type> init_FCSW2_map() {
        std::map<std::string, switches::FCSW2::type> ans;
        ans["Act365Fixed"] = FCSW2::Act365Fixed;
        ans["actual/365 (fixed)"] = FCSW2::Act365Fixed;
        ans["Act360"] = FCSW2::Act360;
        ans["actual/360"] = FCSW2::Act360;
        ans["Act365Act"] = FCSW2::Act365Act;
        ans["actual/365 (actual)"] = FCSW2::Act365Act;
        ans["ISDA30360"] = FCSW2::ISDA30360;
        ans["30/360 (ISDA)"] = FCSW2::ISDA30360;
        ans["ISMA30E360"] = FCSW2::ISMA30E360;
        ans["30E/360 (30/360 ISMA)"] = FCSW2::ISMA30E360;
        return ans;
}
switches::FCSW2::type FCSW2_lookup(const char* fincad_switch) {
        static std::map<std::string, switches::FCSW2::type> switch_map = init_FCSW2_map();
        std::map<std::string, switches::FCSW2::type>::iterator it = switch_map.find(fincad_switch);
        if(it != switch_map.end()) {
                return it->second;
        } else {
                throw FCSwitchLookupError("Bad Match: FCSW2");
        }
}

Seems like you want to go the other way (enum to string, rather than string to enum), but this should be trivial to reverse.

-Whit

Hide text using css

So many complicated solutions.

The easiest one is simply to use:

color:rgba(0,0,0,0)

String replacement in Objective-C

NSString objects are immutable (they can't be changed), but there is a mutable subclass, NSMutableString, that gives you several methods for replacing characters within a string. It's probably your best bet.

How to add column if not exists on PostgreSQL?

Following select query will return true/false, using EXISTS() function.

EXISTS():
The argument of EXISTS is an arbitrary SELECT statement, or subquery. The subquery is evaluated to determine whether it returns any rows. If it returns at least one row, the result of EXISTS is "true"; if the subquery returns no rows, the result of EXISTS is "false"

SELECT EXISTS(SELECT  column_name 
                FROM  information_schema.columns 
               WHERE  table_schema = 'public' 
                 AND  table_name = 'x' 
                 AND  column_name = 'y'); 

and use the following dynamic SQL statement to alter your table

DO
$$
BEGIN
IF NOT EXISTS (SELECT column_name 
                 FROM  information_schema.columns 
                WHERE  table_schema = 'public' 
                  AND  table_name = 'x' 
                  AND  column_name = 'y') THEN
ALTER TABLE x ADD COLUMN y int DEFAULT NULL;
ELSE
RAISE NOTICE 'Already exists';
END IF;
END
$$

Are the PUT, DELETE, HEAD, etc methods available in most web browsers?

YES, PUT, DELETE, HEAD etc HTTP methods are available in all modern browsers.

To be compliant with XMLHttpRequest Level 2 browsers must support these methods. To check which browsers support XMLHttpRequest Level 2 I recommend CanIUse:

http://caniuse.com/#feat=xhr2

Only Opera Mini is lacking support atm (juli '15), but Opera Mini lacks support for everything. :)

Executing Javascript code "on the spot" in Chrome?

You can use bookmarklets if you want run bigger scripts in more convenient way and run them automatically by one click.

How do you stash an untracked file?

To stash your working directory including untracked files (especially those that are in the .gitignore) then you probably want to use this cmd:

git stash --include-untracked

(Alternatively, you can use the shorthand -u instead of --include-untracked)

More details:

Update 17 May 2018:

New versions of git now have git stash --all which stashes all files, including untracked and ignored files.
git stash --include-untracked no longer touches ignored files (tested on git 2.16.2).

Original answer below:

Warning, doing this will permanently delete your files if you have any directory/* entries in your gitignore file.

As of version 1.7.7 you can use git stash --include-untracked or git stash save -u to stash untracked files without staging them.

Add (git add) the file and start tracking it. Then stash. Since the entire contents of the file are new, they will be stashed, and you can manipulate it as necessary.

How to do a PUT request with curl?

Using the -X flag with whatever HTTP verb you want:

curl -X PUT -d arg=val -d arg2=val2 localhost:8080

This example also uses the -d flag to provide arguments with your PUT request.

JavaScript Adding an ID attribute to another created Element

Since id is an attribute don't create an id element, just do this:

myPara.setAttribute("id", "id_you_like");

Android: where are downloaded files saved?

In my experience all the files which i have downloaded from internet,gmail are stored in

/sdcard/download

on ics

/sdcard/Download

You can access it using

Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);

Understanding Bootstrap's clearfix class

When a clearfix is used in a parent container, it automatically wraps around all the child elements.

It is usually used after floating elements to clear the float layout.

When float layout is used, it will horizontally align the child elements. Clearfix clears this behaviour.

Example - Bootstrap Panels

In bootstrap, when the class panel is used, there are 3 child types: panel-header, panel-body, panel-footer. All of which have display:block layout but panel-body has a clearfix pre-applied. panel-body is a main container type whereas panel-header & panel-footer isn't intended to be a container, it is just intended to hold some basic text.

If floating elements are added, the parent container does not get wrapped around those elements because the height of floating elements is not inherited by the parent container.

So for panel-header & panel-footer, clearfix is needed to clear the float layout of elements: Clearfix class gives a visual appearance that the height of the parent container has been increased to accommodate all of its child elements.

 <div class="container">
    <div class="panel panel-default">
        <div class="panel-footer">
            <div class="col-xs-6">
                <input type="button" class="btn btn-primary"   value="Button1">
                <input type="button" class="btn btn-primary"   value="Button2">
                <input type="button" class="btn btn-primary"   value="Button3">
            </div>
        </div>
    </div>

    <div class="panel panel-default">
        <div class="panel-footer">
            <div class="col-xs-6">
                <input type="button" class="btn btn-primary"   value="Button1">
                <input type="button" class="btn btn-primary"   value="Button2">
                <input type="button" class="btn btn-primary"   value="Button3">
            </div>
            <div class="clearfix"/>
        </div>
    </div>
</div>

see an example photo here

How to display PDF file in HTML?

Implementation of a PDF file in your HTML web-page is very easy.

<embed src="file_name.pdf" width="800px" height="2100px" />

Make sure to change the width and height for your needs. Good luck!

How to deal with bad_alloc in C++?

You can catch it like any other exception:

try {
  foo();
}
catch (const std::bad_alloc&) {
  return -1;
}

Quite what you can usefully do from this point is up to you, but it's definitely feasible technically.



In general you cannot, and should not try, to respond to this error. bad_alloc indicates that a resource cannot be allocated because not enough memory is available. In most scenarios your program cannot hope to cope with that, and terminating soon is the only meaningful behaviour.

Worse, modern operating systems often over-allocate: on such systems, malloc and new can return a valid pointer even if there is not enough free memory left – std::bad_alloc will never be thrown, or is at least not a reliable sign of memory exhaustion. Instead, attempts to access the allocated memory will then result in a segmentation fault, which is not catchable (you can handle the segmentation fault signal, but you cannot resume the program afterwards).

The only thing you could do when catching std::bad_alloc is to perhaps log the error, and try to ensure a safe program termination by freeing outstanding resources (but this is done automatically in the normal course of stack unwinding after the error gets thrown if the program uses RAII appropriately).

In certain cases, the program may attempt to free some memory and try again, or use secondary memory (= disk) instead of RAM but these opportunities only exist in very specific scenarios with strict conditions:

  1. The application must ensure that it runs on a system that does not overcommit memory, i.e. it signals failure upon allocation rather than later.
  2. The application must be able to free memory immediately, without any further accidental allocations in the meantime.

It’s exceedingly rare that applications have control over point 1 — userspace applications never do, it’s a system-wide setting that requires root permissions to change.1

OK, so let’s assume you’ve fixed point 1. What you can now do is for instance use a LRU cache for some of your data (probably some particularly large business objects that can be regenerated or reloaded on demand). Next, you need to put the actual logic that may fail into a function that supports retry — in other words, if it gets aborted, you can just relaunch it:

lru_cache<widget> widget_cache;

double perform_operation(int widget_id) {
    std::optional<widget> maybe_widget = widget_cache.find_by_id(widget_id);
    if (not maybe_widget) {
        maybe_widget = widget_cache.store(widget_id, load_widget_from_disk(widget_id));
    }
    return maybe_widget->frobnicate();
}

…

for (int num_attempts = 0; num_attempts < MAX_NUM_ATTEMPTS; ++num_attempts) {
    try {
        return perform_operation(widget_id);
    } catch (std::bad_alloc const&) {
        if (widget_cache.empty()) throw; // memory error elsewhere.
        widget_cache.remove_oldest();
    }
}

// Handle too many failed attempts here.

But even here, using std::set_new_handler instead of handling std::bad_alloc provides the same benefit and would be much simpler.


1 If you’re creating an application that does control point 1, and you’re reading this answer, please shoot me an email, I’m genuinely curious about your circumstances.


What is the C++ Standard specified behavior of new in c++?

The usual notion is that if new operator cannot allocate dynamic memory of the requested size, then it should throw an exception of type std::bad_alloc.
However, something more happens even before a bad_alloc exception is thrown:

C++03 Section 3.7.4.1.3: says

An allocation function that fails to allocate storage can invoke the currently installed new_handler(18.4.2.2), if any. [Note: A program-supplied allocation function can obtain the address of the currently installed new_handler using the set_new_handler function (18.4.2.3).] If an allocation function declared with an empty exception-specification (15.4), throw(), fails to allocate storage, it shall return a null pointer. Any other allocation function that fails to allocate storage shall only indicate failure by throw-ing an exception of class std::bad_alloc (18.4.2.1) or a class derived from std::bad_alloc.

Consider the following code sample:

#include <iostream>
#include <cstdlib>

// function to call if operator new can't allocate enough memory or error arises
void outOfMemHandler()
{
    std::cerr << "Unable to satisfy request for memory\n";

    std::abort();
}

int main()
{
    //set the new_handler
    std::set_new_handler(outOfMemHandler);

    //Request huge memory size, that will cause ::operator new to fail
    int *pBigDataArray = new int[100000000L];

    return 0;
}

In the above example, operator new (most likely) will be unable to allocate space for 100,000,000 integers, and the function outOfMemHandler() will be called, and the program will abort after issuing an error message.

As seen here the default behavior of new operator when unable to fulfill a memory request, is to call the new-handler function repeatedly until it can find enough memory or there is no more new handlers. In the above example, unless we call std::abort(), outOfMemHandler() would be called repeatedly. Therefore, the handler should either ensure that the next allocation succeeds, or register another handler, or register no handler, or not return (i.e. terminate the program). If there is no new handler and the allocation fails, the operator will throw an exception.

What is the new_handler and set_new_handler?

new_handler is a typedef for a pointer to a function that takes and returns nothing, and set_new_handler is a function that takes and returns a new_handler.

Something like:

typedef void (*new_handler)();
new_handler set_new_handler(new_handler p) throw();

set_new_handler's parameter is a pointer to the function operator new should call if it can't allocate the requested memory. Its return value is a pointer to the previously registered handler function, or null if there was no previous handler.

How to handle out of memory conditions in C++?

Given the behavior of newa well designed user program should handle out of memory conditions by providing a proper new_handlerwhich does one of the following:

Make more memory available: This may allow the next memory allocation attempt inside operator new's loop to succeed. One way to implement this is to allocate a large block of memory at program start-up, then release it for use in the program the first time the new-handler is invoked.

Install a different new-handler: If the current new-handler can't make any more memory available, and of there is another new-handler that can, then the current new-handler can install the other new-handler in its place (by calling set_new_handler). The next time operator new calls the new-handler function, it will get the one most recently installed.

(A variation on this theme is for a new-handler to modify its own behavior, so the next time it's invoked, it does something different. One way to achieve this is to have the new-handler modify static, namespace-specific, or global data that affects the new-handler's behavior.)

Uninstall the new-handler: This is done by passing a null pointer to set_new_handler. With no new-handler installed, operator new will throw an exception ((convertible to) std::bad_alloc) when memory allocation is unsuccessful.

Throw an exception convertible to std::bad_alloc. Such exceptions are not be caught by operator new, but will propagate to the site originating the request for memory.

Not return: By calling abort or exit.

PHP "pretty print" json_encode

And for PHP 5.3, you can use this function, which can be embedded in a class or used in procedural style:

http://svn.kd2.org/svn/misc/libs/tools/json_readable_encode.php

How to maximize the browser window in Selenium WebDriver (Selenium 2) using C#?

Through the below code i'm able to maximize the window,

((JavascriptExecutor) driver).executeScript("if(window.screen){
    window.moveTo(0, 0);
    window.resizeTo(window.screen.availWidth, window.screen.availHeight);
    };");

Declaring and using MySQL varchar variables

If you are using phpmyadmin to add new routine then don't forget to wrap your code between BEGIN and ENDenter image description here

How to list all properties of a PowerShell object

If you want to know what properties (and methods) there are:

Get-WmiObject -Class "Win32_computersystem" | Get-Member

Default optional parameter in Swift function

Default value doesn't mean default value of data type .Here default value mean value defined at the time of defining function. we have to declare default value of variable while defining variable in function.

"for" vs "each" in Ruby

As far as I know, using blocks instead of in-language control structures is more idiomatic.

ng-repeat :filter by single field

my way is this

subjcts is

[{"id":"1","title":"GFATM"},{"id":"2","title":"Court Case"},{"id":"3","title":"Renewal\/Validity"},{"id":"4","title":"Change of Details"},{"id":"5","title":"Student Query"},{"id":"6","title":"Complains"}]

sub is a Input field or whatever you like

Displaying like this

<div ng-if="x.id === sub" ng-repeat=" x in subjcts">{{x.title}}</div>

Should composer.lock be committed to version control?

If you’re concerned about your code breaking, you should commit the composer.lock to your version control system to ensure all your project collaborators are using the same version of the code. Without a lock file, you will get new third-party code being pulled down each time.

The exception is when you use a meta apps, libraries where the dependencies should be updated on install (like the Zend Framework 2 Skeleton App). So the aim is to grab the latest dependencies each time when you want to start developing.

Source: Composer: It’s All About the Lock File

See also: What are the differences between composer update and composer install?

How to represent matrices in python

If you are not going to use the NumPy library, you can use the nested list. This is code to implement the dynamic nested list (2-dimensional lists).

Let r is the number of rows

let r=3

m=[]
for i in range(r):
    m.append([int(x) for x in raw_input().split()])

Any time you can append a row using

m.append([int(x) for x in raw_input().split()])

Above, you have to enter the matrix row-wise. To insert a column:

for i in m:
    i.append(x) # x is the value to be added in column

To print the matrix:

print m       # all in single row

for i in m:
    print i   # each row in a different line

OpenVPN failed connection / All TAP-Win32 adapters on this system are currently in use

I found a solution to this. It's bloody witchcraft, but it works.

When you install the client, open Control Panel > Network Connections.

You'll see a disabled network connection that was added by the TAP installer (Local Area Connection 3 or some such).

Right Click it, click Enable.

The device will not reset itself to enabled, but that's ok; try connecting w/ the client again. It'll work.

Difference between webdriver.Dispose(), .Close() and .Quit()

close() is a webdriver command which closes the browser window which is currently in focus. Despite the familiar name for this method, WebDriver does not implement the AutoCloseable interface.

During the automation process, if there are more than one browser window opened, then the close() command will close only the current browser window which is having focus at that time. The remaining browser windows will not be closed. The following code can be used to close the current browser window:

quit() is a webdriver command which calls the driver.dispose method, which in turn closes all the browser windows and terminates the WebDriver session. If we do not use quit() at the end of program, the WebDriver session will not be closed properly and the files will not be cleared off memory. This may result in memory leak errors.

If the Automation process opens only a single browser window, the close() and quit() commands work in the same way. Both will differ in their functionality when there are more than one browser window opened during Automation.

For Above Ref : click here

Dispose Command Dispose() should call Quit(), and it appears it does. However, it also has the same problem in that any subsequent actions are blocked until PhantomJS is manually closed.

Ref Link

How to copy from CSV file to PostgreSQL table with headers in CSV file?

With the Python library pandas, you can easily create column names and infer data types from a csv file.

from sqlalchemy import create_engine
import pandas as pd

engine = create_engine('postgresql://user:pass@localhost/db_name')
df = pd.read_csv('/path/to/csv_file')
df.to_sql('pandas_db', engine)

The if_exists parameter can be set to replace or append to an existing table, e.g. df.to_sql('pandas_db', engine, if_exists='replace'). This works for additional input file types as well, docs here and here.

How to check if another instance of my shell script is running

The cleanest fastest way:

processAlreadyRunning () {
    process="$(basename "${0}")"
    pidof -x "${process}" -o $$ &>/dev/null
}

How can I define colors as variables in CSS?

It’s not possible with CSS alone.

You can do it with JavaScript and LESS using less.js, which will render LESS variables into CSS live, but it’s for development only and adds too much overhead for real-life use.

The closest you can come with CSS is to use an attribute substring selector like this:

[id*="colvar-"] {
    color: #f0c69b;
}

and set the ids of all your elements that you want to be adjusted to names starting with colvar-, such as colvar-header. Then when you change the color, all the ID styles are updated. That’s as close as you can get with CSS alone.

default value for struct member in C

You can use some function to initialize struct as follows,

typedef struct
{
    int flag;
} MyStruct;

MyStruct GetMyStruct(int value)
{
    MyStruct My = {0};
    My.flag = value;
    return My;
}

void main (void)
{
    MyStruct temp;
    temp = GetMyStruct(3);
    printf("%d\n", temp.flag);
}

EDIT:

typedef struct
{
    int flag;
} MyStruct;

MyStruct MyData[20];

MyStruct GetMyStruct(int value)
{
    MyStruct My = {0};
    My.flag = value;
    return My;
}

void main (void)
{
    int i;
    for (i = 0; i < 20; i ++)
        MyData[i] = GetMyStruct(3);

    for (i = 0; i < 20; i ++)
        printf("%d\n", MyData[i].flag);
}

Is it possible to use Java 8 for Android development?

Yes. We will use Java 8 soon!

We've decided to add support for Java 8 language features directly into the current javac and dx set of tools, and deprecate the Jack toolchain. With this new direction, existing tools and plugins dependent on the Java class file format should continue to work. Moving forward, Java 8 language features will be natively supported by the Android build system. We're aiming to launch this as part of Android Studio in the coming weeks, and we wanted to share this decision early with you.

https://android-developers.googleblog.com/2017/03/future-of-java-8-language-feature.html

Regex to match URL end-of-line or "/" character

/(.+)/(\d{4}-\d{2}-\d{2})-(\d+)(/.*)?$

1st Capturing Group (.+)

.+ matches any character (except for line terminators)

  • + Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)

2nd Capturing Group (\d{4}-\d{2}-\d{2})

\d{4} matches a digit (equal to [0-9])

  • {4} Quantifier — Matches exactly 4 times

- matches the character - literally (case sensitive)

\d{2} matches a digit (equal to [0-9])

  • {2} Quantifier — Matches exactly 2 times

- matches the character - literally (case sensitive)

\d{2} matches a digit (equal to [0-9])

  • {2} Quantifier — Matches exactly 2 times

- matches the character - literally (case sensitive)

3rd Capturing Group (\d+)

\d+ matches a digit (equal to [0-9])

  • + Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)

4th Capturing Group (.*)?

? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)

.* matches any character (except for line terminators)

  • * Quantifier — Matches between zero and unlimited times, as many times as possible, giving back as needed (greedy)

$ asserts position at the end of the string

Using AES encryption in C#

http://www.codeproject.com/Articles/769741/Csharp-AES-bits-Encryption-Library-with-Salt

using System.Security.Cryptography;
using System.IO;

 

public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
{
    byte[] encryptedBytes = null;
    byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
    using (MemoryStream ms = new MemoryStream())
    {
        using (RijndaelManaged AES = new RijndaelManaged())
        {
            AES.KeySize = 256;
            AES.BlockSize = 128;
            var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
            AES.Key = key.GetBytes(AES.KeySize / 8);
            AES.IV = key.GetBytes(AES.BlockSize / 8);
            AES.Mode = CipherMode.CBC;
            using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
            {
                cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
                cs.Close();
            }
            encryptedBytes = ms.ToArray();
        }
    }
    return encryptedBytes;
}

public byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
{
    byte[] decryptedBytes = null;
    byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
    using (MemoryStream ms = new MemoryStream())
    {
        using (RijndaelManaged AES = new RijndaelManaged())
        {
            AES.KeySize = 256;
            AES.BlockSize = 128;
            var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
            AES.Key = key.GetBytes(AES.KeySize / 8);
            AES.IV = key.GetBytes(AES.BlockSize / 8);
            AES.Mode = CipherMode.CBC;
            using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
            {
                cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
                cs.Close();
            }
            decryptedBytes = ms.ToArray();
        }
    }
    return decryptedBytes;
}

How to check if all of the following items are in a list?

I like these two because they seem the most logical, the latter being shorter and probably fastest (shown here using set literal syntax which has been backported to Python 2.7):

all(x in {'a', 'b', 'c'} for x in ['a', 'b'])
#   or
{'a', 'b'}.issubset({'a', 'b', 'c'})

How to serve up a JSON response using Go?

You may use this package renderer, I have written to solve this kind of problem, it's a wrapper to serve JSON, JSONP, XML, HTML etc.

How to declare and display a variable in Oracle

Did you recently switch from MySQL and are now longing for the logical equivalents of its more simple commands in Oracle? Because that is the case for me and I had the very same question. This code will give you a quick and dirty print which I think is what you're looking for:

Variable n number
begin
    :n := 1;
end;
print n

The middle section is a PL/SQL bit that binds the variable. The output from print n is in column form, and will not just give the value of n, I'm afraid. When I ran it in Toad 11 it returned like this

        n
---------
        1

I hope that helps

Render partial from different folder (not shared)

The VirtualPathProviderViewEngine, on which the WebFormsViewEngine is based, is supposed to support the "~" and "/" characters at the front of the path so your examples above should work.

I noticed your examples use the path "~/Account/myPartial.ascx", but you mentioned that your user control is in the Views/Account folder. Have you tried

<%Html.RenderPartial("~/Views/Account/myPartial.ascx");%>

or is that just a typo in your question?

Subtracting Dates in Oracle - Number or Interval Datatype?

Ok, I don't normally answer my own questions but after a bit of tinkering, I have figured out definitively how Oracle stores the result of a DATE subtraction.

When you subtract 2 dates, the value is not a NUMBER datatype (as the Oracle 11.2 SQL Reference manual would have you believe). The internal datatype number of a DATE subtraction is 14, which is a non-documented internal datatype (NUMBER is internal datatype number 2). However, it is actually stored as 2 separate two's complement signed numbers, with the first 4 bytes used to represent the number of days and the last 4 bytes used to represent the number of seconds.

An example of a DATE subtraction resulting in a positive integer difference:

select date '2009-08-07' - date '2008-08-08' from dual;

Results in:

DATE'2009-08-07'-DATE'2008-08-08'
---------------------------------
                              364

select dump(date '2009-08-07' - date '2008-08-08') from dual;

DUMP(DATE'2009-08-07'-DATE'2008
-------------------------------
Typ=14 Len=8: 108,1,0,0,0,0,0,0

Recall that the result is represented as a 2 seperate two's complement signed 4 byte numbers. Since there are no decimals in this case (364 days and 0 hours exactly), the last 4 bytes are all 0s and can be ignored. For the first 4 bytes, because my CPU has a little-endian architecture, the bytes are reversed and should be read as 1,108 or 0x16c, which is decimal 364.

An example of a DATE subtraction resulting in a negative integer difference:

select date '1000-08-07' - date '2008-08-08' from dual;

Results in:

DATE'1000-08-07'-DATE'2008-08-08'
---------------------------------
                          -368160

select dump(date '1000-08-07' - date '2008-08-08') from dual;

DUMP(DATE'1000-08-07'-DATE'2008-08-0
------------------------------------
Typ=14 Len=8: 224,97,250,255,0,0,0,0

Again, since I am using a little-endian machine, the bytes are reversed and should be read as 255,250,97,224 which corresponds to 11111111 11111010 01100001 11011111. Now since this is in two's complement signed binary numeral encoding, we know that the number is negative because the leftmost binary digit is a 1. To convert this into a decimal number we would have to reverse the 2's complement (subtract 1 then do the one's complement) resulting in: 00000000 00000101 10011110 00100000 which equals -368160 as suspected.

An example of a DATE subtraction resulting in a decimal difference:

select to_date('08/AUG/2004 14:00:00', 'DD/MON/YYYY HH24:MI:SS'
 - to_date('08/AUG/2004 8:00:00', 'DD/MON/YYYY HH24:MI:SS') from dual;

TO_DATE('08/AUG/200414:00:00','DD/MON/YYYYHH24:MI:SS')-TO_DATE('08/AUG/20048:00:
--------------------------------------------------------------------------------
                                                                             .25

The difference between those 2 dates is 0.25 days or 6 hours.

select dump(to_date('08/AUG/2004 14:00:00', 'DD/MON/YYYY HH24:MI:SS')
 - to_date('08/AUG/2004 8:00:00', 'DD/MON/YYYY HH24:MI:SS')) from dual;

DUMP(TO_DATE('08/AUG/200414:00:
-------------------------------
Typ=14 Len=8: 0,0,0,0,96,84,0,0

Now this time, since the difference is 0 days and 6 hours, it is expected that the first 4 bytes are 0. For the last 4 bytes, we can reverse them (because CPU is little-endian) and get 84,96 = 01010100 01100000 base 2 = 21600 in decimal. Converting 21600 seconds to hours gives you 6 hours which is the difference which we expected.

Hope this helps anyone who was wondering how a DATE subtraction is actually stored.


You get the syntax error because the date math does not return a NUMBER, but it returns an INTERVAL:

SQL> SELECT DUMP(SYSDATE - start_date) from test;

DUMP(SYSDATE-START_DATE)
-------------------------------------- 
Typ=14 Len=8: 188,10,0,0,223,65,1,0

You need to convert the number in your example into an INTERVAL first using the NUMTODSINTERVAL Function

For example:

SQL> SELECT (SYSDATE - start_date) DAY(5) TO SECOND from test;

(SYSDATE-START_DATE)DAY(5)TOSECOND
----------------------------------
+02748 22:50:04.000000

SQL> SELECT (SYSDATE - start_date) from test;

(SYSDATE-START_DATE)
--------------------
           2748.9515

SQL> select NUMTODSINTERVAL(2748.9515, 'day') from dual;

NUMTODSINTERVAL(2748.9515,'DAY')
--------------------------------
+000002748 22:50:09.600000000

SQL>

Based on the reverse cast with the NUMTODSINTERVAL() function, it appears some rounding is lost in translation.

Rename file with Git

I had a similar problem going through a tutorial.

# git mv README README.markdown

fatal: bad source, source=README, destination=README.markdown

I included the filetype in the source file:

# git mv README.rdoc README.markdown

and it worked perfectly. Don't forget to commit the changes with i.e.:

# git commit -a -m "Improved the README"

Sometimes it is simple little things like that, that piss us off. LOL

jQuery get textarea text

You should have a div that just contains the console messages, that is, previous commands and their output. And underneath put an input or textarea that just holds the command you are typing.

-------------------------------
| consle output ...           |
| more output                 |
| prevous commands and data   |
-------------------------------
> This is an input box.

That way you just send the value of the input box to the server for processing, and append the result to the console messages div.

Git: How to pull a single file from a server repository in Git?

Try using:

git checkout branchName -- fileName

Ex:

git checkout master -- index.php

How to get commit history for just one branch?

You can use only git log --oneline

What is dynamic programming?

Here is a simple python code example of Recursive, Top-down, Bottom-up approach for Fibonacci series:

Recursive: O(2n)

def fib_recursive(n):
    if n == 1 or n == 2:
        return 1
    else:
        return fib_recursive(n-1) + fib_recursive(n-2)


print(fib_recursive(40))

Top-down: O(n) Efficient for larger input

def fib_memoize_or_top_down(n, mem):
    if mem[n] is not 0:
        return mem[n]
    else:
        mem[n] = fib_memoize_or_top_down(n-1, mem) + fib_memoize_or_top_down(n-2, mem)
        return mem[n]


n = 40
mem = [0] * (n+1)
mem[1] = 1
mem[2] = 1
print(fib_memoize_or_top_down(n, mem))

Bottom-up: O(n) For simplicity and small input sizes

def fib_bottom_up(n):
    mem = [0] * (n+1)
    mem[1] = 1
    mem[2] = 1
    if n == 1 or n == 2:
        return 1

    for i in range(3, n+1):
        mem[i] = mem[i-1] + mem[i-2]

    return mem[n]


print(fib_bottom_up(40))

How do I convert an existing callback API to promises?

Promises have state, they start as pending and can settle to:

  • fulfilled meaning that the computation completed successfully.
  • rejected meaning that the computation failed.

Promise returning functions should never throw, they should return rejections instead. Throwing from a promise returning function will force you to use both a } catch { and a .catch. People using promisified APIs do not expect promises to throw. If you're not sure how async APIs work in JS - please see this answer first.

1. DOM load or other one time event:

So, creating promises generally means specifying when they settle - that means when they move to the fulfilled or rejected phase to indicate the data is available (and can be accessed with .then).

With modern promise implementations that support the Promise constructor like native ES6 promises:

function load() {
    return new Promise(function(resolve, reject) {
        window.onload = resolve;
    });
}

You would then use the resulting promise like so:

load().then(function() {
    // Do things after onload
});

With libraries that support deferred (Let's use $q for this example here, but we'll also use jQuery later):

function load() {
    var d = $q.defer();
    window.onload = function() { d.resolve(); };
    return d.promise;
}

Or with a jQuery like API, hooking on an event happening once:

function done() {
    var d = $.Deferred();
    $("#myObject").once("click",function() {
        d.resolve();
    });
    return d.promise();
}

2. Plain callback:

These APIs are rather common since well… callbacks are common in JS. Let's look at the common case of having onSuccess and onFail:

function getUserData(userId, onLoad, onFail) { …

With modern promise implementations that support the Promise constructor like native ES6 promises:

function getUserDataAsync(userId) {
    return new Promise(function(resolve, reject) {
        getUserData(userId, resolve, reject);
    });
}

With libraries that support deferred (Let's use jQuery for this example here, but we've also used $q above):

function getUserDataAsync(userId) {
    var d = $.Deferred();
    getUserData(userId, function(res){ d.resolve(res); }, function(err){ d.reject(err); });
    return d.promise();
}

jQuery also offers a $.Deferred(fn) form, which has the advantage of allowing us to write an expression that emulates very closely the new Promise(fn) form, as follows:

function getUserDataAsync(userId) {
    return $.Deferred(function(dfrd) {
        getUserData(userId, dfrd.resolve, dfrd.reject);
    }).promise();
}

Note: Here we exploit the fact that a jQuery deferred's resolve and reject methods are "detachable"; ie. they are bound to the instance of a jQuery.Deferred(). Not all libs offer this feature.

3. Node style callback ("nodeback"):

Node style callbacks (nodebacks) have a particular format where the callbacks is always the last argument and its first parameter is an error. Let's first promisify one manually:

getStuff("dataParam", function(err, data) { …

To:

function getStuffAsync(param) {
    return new Promise(function(resolve, reject) {
        getStuff(param, function(err, data) {
            if (err !== null) reject(err);
            else resolve(data);
        });
    });
}

With deferreds you can do the following (let's use Q for this example, although Q now supports the new syntax which you should prefer):

function getStuffAsync(param) {
    var d = Q.defer();
    getStuff(param, function(err, data) {
        if (err !== null) d.reject(err);
        else d.resolve(data);
    });
    return d.promise;   
}

In general, you should not promisify things manually too much, most promise libraries that were designed with Node in mind as well as native promises in Node 8+ have a built in method for promisifying nodebacks. For example

var getStuffAsync = Promise.promisify(getStuff); // Bluebird
var getStuffAsync = Q.denodeify(getStuff); // Q
var getStuffAsync = util.promisify(getStuff); // Native promises, node only

4. A whole library with node style callbacks:

There is no golden rule here, you promisify them one by one. However, some promise implementations allow you to do this in bulk, for example in Bluebird, converting a nodeback API to a promise API is as simple as:

Promise.promisifyAll(API);

Or with native promises in Node:

const { promisify } = require('util');
const promiseAPI = Object.entries(API).map(([key, v]) => ({key, fn: promisify(v)}))
                         .reduce((o, p) => Object.assign(o, {[p.key]: p.fn}), {});

Notes:

  • Of course, when you are in a .then handler you do not need to promisify things. Returning a promise from a .then handler will resolve or reject with that promise's value. Throwing from a .then handler is also good practice and will reject the promise - this is the famous promise throw safety.
  • In an actual onload case, you should use addEventListener rather than onX.