Programs & Examples On #Factory method

A design pattern which defines an interface for creating an object, but lets the classes that implement the interface decide which class to instantiate. One of the Gang of Four's creational design patterns.

Factory Pattern. When to use factory methods?

It is important to clearly differentiate the idea behind using factory or factory method. Both are meant to address mutually exclusive different kind of object creation problems.

Let's be specific about "factory method":

First thing is that, when you are developing library or APIs which in turn will be used for further application development, then factory method is one of the best selections for creation pattern. Reason behind; We know that when to create an object of required functionality(s) but type of object will remain undecided or it will be decided ob dynamic parameters being passed.

Now the point is, approximately same can be achieved by using factory pattern itself but one huge drawback will introduce into the system if factory pattern will be used for above highlighted problem, it is that your logic of crating different objects(sub classes objects) will be specific to some business condition so in future when you need to extend your library's functionality for other platforms(In more technically, you need to add more sub classes of basic interface or abstract class so factory will return those objects also in addition to existing one based on some dynamic parameters) then every time you need to change(extend) the logic of factory class which will be costly operation and not good from design perspective. On the other side, if "factory method" pattern will be used to perform the same thing then you just need to create additional functionality(sub classes) and get it registered dynamically by injection which doesn't require changes in your base code.

interface Deliverable 
{
    /*********/
}

abstract class DefaultProducer 
{

    public void taskToBeDone() 
    {   
        Deliverable deliverable = factoryMethodPattern();
    }
    protected abstract Deliverable factoryMethodPattern();
}

class SpecificDeliverable implements Deliverable 
{
 /***SPECIFIC TASK CAN BE WRITTEN HERE***/
}

class SpecificProducer extends DefaultProducer 
{
    protected Deliverable factoryMethodPattern() 
    {
        return new SpecificDeliverable();
    }
}

public class MasterApplicationProgram 
{
    public static void main(String arg[]) 
    {
        DefaultProducer defaultProducer = new SpecificProducer();
        defaultProducer.taskToBeDone();
    }
}

What are static factory methods?

The static factory method pattern is a way to encapsulate object creation. Without a factory method, you would simply call the class's constructor directly: Foo x = new Foo(). With this pattern, you would instead call the factory method: Foo x = Foo.create(). The constructors are marked private, so they cannot be called except from inside the class, and the factory method is marked as static so that it can be called without first having an object.

There are a few advantages to this pattern. One is that the factory can choose from many subclasses (or implementers of an interface) and return that. This way the caller can specify the behavior desired via parameters, without having to know or understand a potentially complex class hierarchy.

Another advantage is, as Matthew and James have pointed out, controlling access to a limited resource such as connections. This a way to implement pools of reusable objects - instead of building, using, and tearing down an object, if the construction and destruction are expensive processes it might make more sense to build them once and recycle them. The factory method can return an existing, unused instantiated object if it has one, or construct one if the object count is below some lower threshold, or throw an exception or return null if it's above the upper threshold.

As per the article on Wikipedia, multiple factory methods also allow different interpretations of similar argument types. Normally the constructor has the same name as the class, which means that you can only have one constructor with a given signature. Factories are not so constrained, which means you can have two different methods that accept the same argument types:

Coordinate c = Coordinate.createFromCartesian(double x, double y)

and

Coordinate c = Coordinate.createFromPolar(double distance, double angle)

This can also be used to improve readability, as Rasmus notes.

What is the basic difference between the Factory and Abstract Factory Design Patterns?

Both Factory Method and Abstract Factory keep the clients decoupled from the concrete types. Both create objects, but Factory method uses inheritance whereas Abstract Factory use composition.

The Factory Method is inherited in subclasses to create the concrete objects(products) whereas Abstract Factory provide interface for creating the family of related products and subclass of these interface define how to create related products.

Then these subclasses when instantiated is passed into product classes where it is used as abstract type. The related products in an Abstract Factory are often implemented using Factory Method.

What is the difference between Builder Design pattern and Factory Design pattern?

+-------------------------------------------------------------------+---------------------------------------------------+
|                              Builder                              |                      Factory                      |
+-------------------------------------------------------------------+---------------------------------------------------+
| Return only single instance to handle complex object construction | Retrun various instances on multiple constructors |
| No interface required                                             | Interface driven                                  |
| Inner classes is involved (to avoid telescopic constructors)      | Subclasses are involved                           |
+-------------------------------------------------------------------+---------------------------------------------------+  

Telescoping Constructor Pattern

Analogy:

  • Factory: Consider a restaurant. The creation of "today's meal" is a factory pattern, because you tell the kitchen "get me today's meal" and the kitchen (factory) decides what object to generate, based on hidden criteria.
  • Builder: The builder appears if you order a custom pizza. In this case, the waiter tells the chef (builder) "I need a pizza; add cheese, onions and bacon to it!" Thus, the builder exposes the attributes the generated object should have, but hides how to set them.

Courtesy

What are the differences between Abstract Factory and Factory design patterns?

Difference between AbstractFactory and Factory design patterns are as follows:

  • Factory Method is used to create one product only but Abstract Factory is about creating families of related or dependent products.
  • Factory Method pattern exposes a method to the client for creating the object whereas in the case of Abstract Factory they expose a family of related objects which may consist of these Factory methods.
  • Factory Method pattern hides the construction of a single object whereas Abstract Factory hides the construction of a family of related objects. Abstract factories are usually implemented using (a set of) factory methods.
  • Abstract Factory pattern uses composition to delegate the responsibility of creating an object to another class while Factory Method design pattern uses inheritance and relies on a derived class or subclass to create an object.
  • The idea behind the Factory Method pattern is that it allows for the case where a client doesn't know what concrete classes it will be required to create at runtime, but just wants to get a class that will do the job while Abstract Factory pattern is best utilized when your system has to create multiple families of products or you want to provide a library of products without exposing the implementation details.!

Factory Method Pattern Implementation: Factory Method UML

Abstract Factory Pattern Implementation:

Abstract Factory UML

How to implement the factory method pattern in C++ correctly

I mostly agree with the accepted answer, but there is a C++11 option that has not been covered in existing answers:

  • Return factory method results by value, and
  • Provide a cheap move constructor.

Example:

struct sandwich {
  // Factory methods.
  static sandwich ham();
  static sandwich spam();
  // Move constructor.
  sandwich(sandwich &&);
  // etc.
};

Then you can construct objects on the stack:

sandwich mine{sandwich::ham()};

As subobjects of other things:

auto lunch = std::make_pair(sandwich::spam(), apple{});

Or dynamically allocated:

auto ptr = std::make_shared<sandwich>(sandwich::ham());

When might I use this?

If, on a public constructor, it is not possible to give meaningful initialisers for all class members without some preliminary calculation, then I might convert that constructor to a static method. The static method performs the preliminary calculations, then returns a value result via a private constructor which just does a member-wise initialisation.

I say 'might' because it depends on which approach gives the clearest code without being unnecessarily inefficient.

How to include !important in jquery

I solved this problem with:

inputObj.css('cssText', inputObj.attr('style')+'padding-left: ' + (width + 5) + 'px !IMPORTANT;');

So no inline-Style is lost, an the last overrides the first

How to set date format in HTML date input tag?

short direct answer is no or not out of the box but i have come up with a method to use a text box and pure JS code to simulate the date input and do any format you want, here is the code

<html>
<body>
date : 
<span style="position: relative;display: inline-block;border: 1px solid #a9a9a9;height: 24px;width: 500px">
    <input type="date" class="xDateContainer" onchange="setCorrect(this,'xTime');" style="position: absolute; opacity: 0.0;height: 100%;width: 100%;"><input type="text" id="xTime" name="xTime" value="dd / mm / yyyy" style="border: none;height: 90%;" tabindex="-1"><span style="display: inline-block;width: 20px;z-index: 2;float: right;padding-top: 3px;" tabindex="-1">&#9660;</span>
</span>
<script language="javascript">
var matchEnterdDate=0;
//function to set back date opacity for non supported browsers
    window.onload =function(){
        var input = document.createElement('input');
        input.setAttribute('type','date');
        input.setAttribute('value', 'some text'); 
        if(input.value === "some text"){
            allDates = document.getElementsByClassName("xDateContainer");
            matchEnterdDate=1;
            for (var i = 0; i < allDates.length; i++) {
                allDates[i].style.opacity = "1";
            } 
        }
    }
//function to convert enterd date to any format
function setCorrect(xObj,xTraget){
    var date = new Date(xObj.value);
    var month = date.getMonth();
    var day = date.getDate();
    var year = date.getFullYear();
    if(month!='NaN'){
        document.getElementById(xTraget).value=day+" / "+month+" / "+year;
    }else{
        if(matchEnterdDate==1){document.getElementById(xTraget).value=xObj.value;}
    }
}
   </script>
  </body>
</html>

1- please note that this method only work for browser that support date type.

2- the first function in JS code is for browser that don't support date type and set the look to a normal text input.

3- if you will use this code for multiple date inputs in your page please change the ID "xTime" of the text input in both function call and the input itself to something else and of course use the name of the input you want for the form submit.

4-on the second function you can use any format you want instead of day+" / "+month+" / "+year for example year+" / "+month+" / "+day and in the text input use a placeholder or value as yyyy / mm / dd for the user when the page load.

plotting different colors in matplotlib

@tcaswell already answered, but I was in the middle of typing my answer up, so I'll go ahead and post it...

There are a number of different ways you could do this. To begin with, matplotlib will automatically cycle through colors. By default, it cycles through blue, green, red, cyan, magenta, yellow, black:

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 1, 10)
for i in range(1, 6):
    plt.plot(x, i * x + i, label='$y = {i}x + {i}$'.format(i=i))
plt.legend(loc='best')
plt.show()

enter image description here

If you want to control which colors matplotlib cycles through, use ax.set_color_cycle:

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 1, 10)
fig, ax = plt.subplots()
ax.set_color_cycle(['red', 'black', 'yellow'])
for i in range(1, 6):
    plt.plot(x, i * x + i, label='$y = {i}x + {i}$'.format(i=i))
plt.legend(loc='best')
plt.show()

enter image description here

If you'd like to explicitly specify the colors that will be used, just pass it to the color kwarg (html colors names are accepted, as are rgb tuples and hex strings):

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 1, 10)
for i, color in enumerate(['red', 'black', 'blue', 'brown', 'green'], start=1):
    plt.plot(x, i * x + i, color=color, label='$y = {i}x + {i}$'.format(i=i))
plt.legend(loc='best')
plt.show()

enter image description here

Finally, if you'd like to automatically select a specified number of colors from an existing colormap:

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 1, 10)
number = 5
cmap = plt.get_cmap('gnuplot')
colors = [cmap(i) for i in np.linspace(0, 1, number)]

for i, color in enumerate(colors, start=1):
    plt.plot(x, i * x + i, color=color, label='$y = {i}x + {i}$'.format(i=i))
plt.legend(loc='best')
plt.show()

enter image description here

How do I check if a Socket is currently connected in Java?

  • socket.isConnected() returns always true once the client connects (and even after the disconnect) weird !!
  • socket.getInputStream().read()
    • makes the thread wait for input as long as the client is connected and therefore makes your program not do anything - except if you get some input
    • returns -1 if the client disconnected
  • socket.getInetAddress().isReachable(int timeout): From isReachable(int timeout)

    Test whether that address is reachable. Best effort is made by the implementation to try to reach the host, but firewalls and server configuration may block requests resulting in a unreachable status while some specific ports may be accessible. A typical implementation will use ICMP ECHO REQUESTs if the privilege can be obtained, otherwise it will try to establish a TCP connection on port 7 (Echo) of the destination host.

A method to reverse effect of java String.split()?

For the sake of completeness, I'd like to add that you cannot reverse String#split in general, as it accepts a regular expression.

"hello__world".split("_+"); Yields ["hello", "world"].
"hello_world".split("_+"); Yields ["hello", "world"].

These yield identical results from a different starting point. splitting is not a one-to-one operation, and is thus non-reversible.

This all being said, if you assume your parameter to be a fixed string, not regex, then you can certainly do this using one of the many posted answers.

Center Align on a Absolutely Positioned Div

I know I'm late to the party, but I thought I would provide an answer here for people who need to horizontally position an absolute item, when you don't know its exact width.

Try this:

// Horizontal example.
div#thing {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

The same technique can also be applied, for when you might need vertical alignment, simply by adjusting the properties like so:

// Vertical example.
div#thing {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
}

How to create a <style> tag with Javascript?

An example that works and are compliant with all browsers :

var ss = document.createElement("link");
ss.type = "text/css";
ss.rel = "stylesheet";
ss.href = "style.css";
document.getElementsByTagName("head")[0].appendChild(ss);

Get first day of week in PHP?

$string_date = '2019-07-31';
echo $day_of_week = date('N', strtotime($string_date));
echo $week_first_day = date('Y-m-d', strtotime($string_date . " - " . ($day_of_week - 1) . " days"));
echo $week_last_day = date('Y-m-d', strtotime($string_date . " + " . (7 - $day_of_week) . " days"));

Convert string to nullable type (int, double, etc...)

I like Joel's answer, but I've modified it slightly as I'm not a fan of eating exceptions.

    /// <summary>
    /// Converts a string to the specified nullable type.
    /// </summary>
    /// <typeparam name="T">The type to convert to</typeparam>
    /// <param name="s">The string to convert</param>
    /// <returns>The nullable output</returns>
    public static T? ToNullable<T>(this string s) where T : struct
    {
        if (string.IsNullOrWhiteSpace(s))
            return null;

        TypeConverter conv = TypeDescriptor.GetConverter(typeof (T));
        return (T) conv.ConvertFrom(s);
    }

    /// <summary>
    /// Attempts to convert a string to the specified nullable primative.
    /// </summary>
    /// <typeparam name="T">The primitive type to convert to</typeparam>
    /// <param name="data">The string to convert</param>
    /// <param name="output">The nullable output</param>
    /// <returns>
    /// True if conversion is successfull, false otherwise.  Null and whitespace will
    /// be converted to null and return true.
    /// </returns>
    public static bool TryParseNullable<T>(this string data, out T? output) where T : struct
    {
        try
        {
            output = data.ToNullable<T>();
            return true;
        }
        catch
        {
            output = null;
            return false;
        }
    }

Using Enum values as String literals

public enum Modes {
  MODE1("Mode1"),
  MODE2("Mode2"),
  MODE3("Mode3");

 private String value;
 public String getValue() {
    return value;
   }
 private Modes(String value) {
  this.value = value;
 } 
}

you can make a call like below wherever you want to get the value as a string from the enum.

Modes.MODE1.getvalue();

This will return "Mode1" as a String.

How to use gitignore command in git

on my mac i found this file .gitignore_global ..it was in my home directory hidden so do a ls -altr to see it.

I added eclipse files i wanted git to ignore. the contents looks like this:

 *~
.DS_Store
.project
.settings
.classpath
.metadata

What is a None value?

Other answers have already explained meaning of None beautifully. However, I would still like to throw more light on this using an example.

Example:

def extendList(val, list=[]):
    list.append(val)
    return list

list1 = extendList(10)
list2 = extendList(123,[])
list3 = extendList('a')

print "list1 = %s" % list1
print "list2 = %s" % list2
print "list3 = %s" % list3

Now try to guess output of above list. Well, the answer is surprisingly as below:

list1 = [10, 'a']
list2 = [123]
list3 = [10, 'a']

But Why?

Many will mistakenly expect list1 to be equal to [10] and list3 to be equal to ['a'], thinking that the list argument will be set to its default value of [] each time extendList is called.

However, what actually happens is that the new default list is created only once when the function is defined, and that same list is then used subsequently whenever extendList is invoked without a list argument being specified. This is because expressions in default arguments are calculated when the function is defined, not when it’s called.

list1 and list3 are therefore operating on the same default list, whereas list2 is operating on a separate list that it created (by passing its own empty list as the value for the list parameter).


'None' the savior: (Modify example above to produce desired behavior)

def extendList(val, list=None):
    if list is None:
       list = []
    list.append(val)
    return list

list1 = extendList(10)
list2 = extendList(123,[])
list3 = extendList('a')

print "list1 = %s" % list1
print "list2 = %s" % list2
print "list3 = %s" % list3

With this revised implementation, the output would be:

list1 = [10]
list2 = [123]
list3 = ['a']

Note - Example credit to toptal.com

Purpose of ESI & EDI registers?

SI = Source Index
DI = Destination Index

As others have indicated, they have special uses with the string instructions. For real mode programming, the ES segment register must be used with DI and DS with SI as in

movsb  es:di, ds:si

SI and DI can also be used as general purpose index registers. For example, the C source code

srcp [srcidx++] = argv [j];

compiles into

8B550C         mov    edx,[ebp+0C]
8B0C9A         mov    ecx,[edx+4*ebx]
894CBDAC       mov    [ebp+4*edi-54],ecx
47             inc    edi

where ebp+12 contains argv, ebx is j, and edi has srcidx. Notice the third instruction uses edi mulitplied by 4 and adds ebp offset by 0x54 (the location of srcp); brackets around the address indicate indirection.


Though I can't remember where I saw it, but this confirms most of it, and this (slide 17) others:

AX = accumulator
DX = double word accumulator
CX = counter
BX = base register

They look like general purpose registers, but there are a number of instructions which (unexpectedly?) use one of them—but which one?—implicitly.

Parse large JSON file in Nodejs

I had similar requirement, i need to read a large json file in node js and process data in chunks and call a api and save in mongodb. inputFile.json is like:

{
 "customers":[
       { /*customer data*/},
       { /*customer data*/},
       { /*customer data*/}....
      ]
}

Now i used JsonStream and EventStream to achieve this synchronously.

var JSONStream = require("JSONStream");
var es = require("event-stream");

fileStream = fs.createReadStream(filePath, { encoding: "utf8" });
fileStream.pipe(JSONStream.parse("customers.*")).pipe(
  es.through(function(data) {
    console.log("printing one customer object read from file ::");
    console.log(data);
    this.pause();
    processOneCustomer(data, this);
    return data;
  }),
  function end() {
    console.log("stream reading ended");
    this.emit("end");
  }
);

function processOneCustomer(data, es) {
  DataModel.save(function(err, dataModel) {
    es.resume();
  });
}

Vertically align text next to an image?

Basically, you'll have to get down to CSS3.

-moz-box-align: center;
-webkit-box-align: center;

How to move all files including hidden files into parent directory via *

This will move all files to parent directory like expected but will not move hidden files. How to do that?

You could turn on dotglob:

shopt -s dotglob               # This would cause mv below to match hidden files
mv /path/subfolder/* /path/

In order to turn off dotglob, you'd need to say:

shopt -u dotglob

How many socket connections can a web server handle?

This question is a fairly difficult one. There is no real software limitation on the number of active connections a machine can have, though some OS's are more limited than others. The problem becomes one of resources. For example, let's say a single machine wants to support 64,000 simultaneous connections. If the server uses 1MB of RAM per connection, it would need 64GB of RAM. If each client needs to read a file, the disk or storage array access load becomes much larger than those devices can handle. If a server needs to fork one process per connection then the OS will spend the majority of its time context switching or starving processes for CPU time.

The C10K problem page has a very good discussion of this issue.

How to subtract X days from a date using Java calendar?

int x = -1;
Calendar cal = ...;
cal.add(Calendar.DATE, x);

See java.util.Calendar#add(int,int)

How does EL empty operator work in JSF?

From EL 2.2 specification (get the one below "Click here to download the spec for evaluation"):

1.10 Empty Operator - empty A

The empty operator is a prefix operator that can be used to determine if a value is null or empty.

To evaluate empty A

  • If A is null, return true
  • Otherwise, if A is the empty string, then return true
  • Otherwise, if A is an empty array, then return true
  • Otherwise, if A is an empty Map, return true
  • Otherwise, if A is an empty Collection, return true
  • Otherwise return false

So, considering the interfaces, it works on Collection and Map only. In your case, I think Collection is the best option. Or, if it's a Javabean-like object, then Map. Either way, under the covers, the isEmpty() method is used for the actual check. On interface methods which you can't or don't want to implement, you could throw UnsupportedOperationException.

Send Outlook Email Via Python?

using pywin32:

from win32com.client import Dispatch

session = Dispatch('MAPI.session')
session.Logon('','',0,1,0,0,'exchange.foo.com\nUserName');
msg = session.Outbox.Messages.Add('Hello', 'This is a test')
msg.Recipients.Add('Corey', 'SMTP:[email protected]')
msg.Send()
session.Logoff()

What charset does Microsoft Excel use when saving files?

While it is true that exporting an excel file that contains special characters to csv can be a pain in the ass, there is however a simple work around: simply copy/paste the cells into a google docs and then save from there.

Angular 2 optional route parameter

Facing a similar problem with lazy loading I have done this:

const routes: Routes = [
  {
    path: 'users',
    redirectTo: 'users/',
    pathMatch: 'full'
  },
  {
    path: 'users',
    loadChildren: './users/users.module#UserssModule',
    runGuardsAndResolvers: 'always'
  },
[...]

And then in the component:

  ngOnInit() {
    this.activatedRoute.paramMap.pipe(
      switchMap(
        (params: ParamMap) => {
          let id: string = params.get('id');
          if (id == "") {
            return of(undefined);
          }
          return this.usersService.getUser(Number(params.get('id')));
        }
      )
    ).subscribe(user => this.selectedUser = user);
  }

This way:

  • The route without / is redirected to the route with. Because of the pathMatch: 'full', only such specific full route is redirected.

  • Then, users/:id is received. If the actual route was users/, id is "", so check it in ngOnInit and act accordingly; else, id is the id and proceed.

  • The rest of the componect acts on selectedUser is or not undefined (*ngIf and the things like that).

How to build a query string for a URL in C#?

Just for those that need the VB.NET version of the top-answer:

Public Function ToQueryString(nvc As System.Collections.Specialized.NameValueCollection) As String
    Dim array As String() = nvc.AllKeys.SelectMany(Function(key As String) nvc.GetValues(key), Function(key As String, value As String) String.Format("{0}={1}", System.Web.HttpUtility.UrlEncode(key), System.Web.HttpUtility.UrlEncode(value))).ToArray()
    Return "?" + String.Join("&", array)
End Function

And the version without LINQ:

Public Function ToQueryString(nvc As System.Collections.Specialized.NameValueCollection) As String
    Dim lsParams As New List(Of String)()

    For Each strKey As String In nvc.AllKeys
        Dim astrValue As String() = nvc.GetValues(strKey)

        For Each strValue As String In astrValue
            lsParams.Add(String.Format("{0}={1}", System.Web.HttpUtility.UrlEncode(strKey), System.Web.HttpUtility.UrlEncode(strValue)))
        Next ' Next strValue
    Next ' strKey
    Dim astrParams As String() = lsParams.ToArray()
    lsParams.Clear()
    lsParams = Nothing

    Return "?" + String.Join("&", astrParams)
End Function ' ToQueryString

And the C# version without LINQ:

    public static string ToQueryString(System.Collections.Specialized.NameValueCollection nvc)
    {
        List<string> lsParams = new List<string>();

        foreach (string strKey in nvc.AllKeys)
        {
            string[] astrValue = nvc.GetValues(strKey);

            foreach (string strValue in astrValue)
            {
                lsParams.Add(string.Format("{0}={1}", System.Web.HttpUtility.UrlEncode(strKey), System.Web.HttpUtility.UrlEncode(strValue)));
            } // Next strValue

        } // Next strKey

        string[] astrParams =lsParams.ToArray();
        lsParams.Clear();
        lsParams = null;

        return "?" + string.Join("&", astrParams);
    } // End Function ToQueryString

Difference between an API and SDK

API = Dictionary of available words and their meanings (and the required grammar to combine them)

SDK = A Word processing system… for 2 year old babies… that writes right from ideas

Although you COULD go to school and become a master in your language after a few years, using the SDK will help you write whole meaningful sentences in no time (Forgiving the fact that, in this example, as a baby you haven't even gotten to learn any other language for at least to learn to use the SDK.)

How to send a POST request in Go?

I know this is old but this answer came up in search results. For the next guy - the proposed and accepted answer works, however the code initially submitted in the question is lower-level than it needs to be. Nobody got time for that.

//one-line post request/response...
response, err := http.PostForm(APIURL, url.Values{
    "ln": {c.ln},
    "ip": {c.ip},
    "ua": {c.ua}})

//okay, moving on...
if err != nil {
  //handle postform error
}

defer response.Body.Close()
body, err := ioutil.ReadAll(response.Body)

if err != nil {
  //handle read response error
}

fmt.Printf("%s\n", string(body))

https://golang.org/pkg/net/http/#pkg-overview

How to check whether a str(variable) is empty or not?

The "Pythonic" way to check if a string is empty is:

import random
variable = random.choice(l)
if variable:
    # got a non-empty string
else:
    # got an empty string

Set drawable size programmatically

The setBounds() method doesn't work for every type of container (did work for some of my ImageView's, however).

Try the method below to scale the drawable itself:

// Read your drawable from somewhere
Drawable dr = getResources().getDrawable(R.drawable.somedrawable);
Bitmap bitmap = ((BitmapDrawable) dr).getBitmap();
// Scale it to 50 x 50
Drawable d = new BitmapDrawable(getResources(), Bitmap.createScaledBitmap(bitmap, 50, 50, true));
// Set your new, scaled drawable "d"

How to remove "index.php" in codeigniter's path

If you are using Apache place a .htaccess file in your root web directory containing the following:

RewriteEngine on
RewriteCond $1 !^(index\.php|[Javascript / CSS / Image root Folder name(s)]|robots\.txt)
RewriteRule ^(.*)$ /index.php/$1 [L]

Another good version is located here:

http://snipplr.com/view/5966/codeigniter-htaccess/

Can I install/update WordPress plugins without providing FTP access?

WordPress 2.7 lets you upload a zip file directly (there's a link at the bottom of the plugins page) -- no FTP access needed. This is a new feature in 2.7, and it works for plugins only (not themes yet).

HTTP GET in VBS

Dim o
Set o = CreateObject("MSXML2.XMLHTTP")
o.open "GET", "http://www.example.com", False
o.send
' o.responseText now holds the response as a string.

Using a cursor with dynamic SQL in a stored procedure

A cursor will only accept a select statement, so if the SQL really needs to be dynamic make the declare cursor part of the statement you are executing. For the below to work your server will have to be using global cursors.

Declare @UserID varchar(100)
declare @sqlstatement nvarchar(4000)
--move declare cursor into sql to be executed
set @sqlstatement = 'Declare  users_cursor CURSOR FOR SELECT userId FROM users'

exec sp_executesql @sqlstatement


OPEN users_cursor
FETCH NEXT FROM users_cursor
INTO @UserId

WHILE @@FETCH_STATUS = 0
BEGIN
Print @UserID
EXEC asp_DoSomethingStoredProc @UserId

FETCH NEXT FROM users_cursor --have to fetch again within loop
INTO @UserId

END
CLOSE users_cursor
DEALLOCATE users_cursor

If you need to avoid using the global cursors, you could also insert the results of your dynamic SQL into a temporary table, and then use that table to populate your cursor.

Declare @UserID varchar(100)
create table #users (UserID varchar(100))

declare @sqlstatement nvarchar(4000)
set @sqlstatement = 'Insert into #users (userID) SELECT userId FROM users'
exec(@sqlstatement)

declare users_cursor cursor for Select UserId from #Users
OPEN users_cursor
FETCH NEXT FROM users_cursor
INTO @UserId

WHILE @@FETCH_STATUS = 0
BEGIN

EXEC asp_DoSomethingStoredProc @UserId

FETCH NEXT FROM users_cursor
INTO @UserId

END
CLOSE users_cursor
DEALLOCATE users_cursor

drop table #users

Get generic type of java.util.List

import org.junit.Assert;
import org.junit.Test;

import java.lang.reflect.Field;
import java.lang.reflect.ParameterizedType;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class GenericTypeOfCollectionTest {
    public class FormBean {
    }

    public class MyClazz {
        private List<FormBean> list = new ArrayList<FormBean>();
    }

    @Test
    public void testName() throws Exception {
        Field[] fields = MyClazz.class.getFields();
        for (Field field : fields) {
            //1. Check if field is of Collection Type
            if (Collection.class.isAssignableFrom(field.getType())) {
                //2. Get Generic type of your field
                Class fieldGenericType = getFieldGenericType(field);
                //3. Compare with <FromBean>
                Assert.assertTrue("List<FormBean>",
                  FormBean.class.isAssignableFrom(fieldGenericType));
            }
        }
    }

    //Returns generic type of any field
    public Class getFieldGenericType(Field field) {
        if (ParameterizedType.class.isAssignableFrom(field.getGenericType().getClass())) {
            ParameterizedType genericType =
             (ParameterizedType) field.getGenericType();
            return ((Class)
              (genericType.getActualTypeArguments()[0])).getSuperclass();
        }
        //Returns dummy Boolean Class to compare with ValueObject & FormBean
        return new Boolean(false).getClass();
    }
}

Find a file with a certain extension in folder

The method below returns only the files with certain extension (eg: file with .txt but not .txt1)

public static IEnumerable<string> GetFilesByExtension(string directoryPath, string extension, SearchOption searchOption)
    {
        return
            Directory.EnumerateFiles(directoryPath, "*" + extension, searchOption)
                .Where(x => string.Equals(Path.GetExtension(x), extension, StringComparison.InvariantCultureIgnoreCase));
    }

What is newline character -- '\n'

Try this:

$ sed -e $'s/\n/\n\n/g' states

How to replace ${} placeholders in a text file?

Use /bin/sh. Create a small shell script that sets the variables, and then parse the template using the shell itself. Like so (edit to handle newlines correctly):

File template.txt:

the number is ${i}
the word is ${word}

File script.sh:

#!/bin/sh

#Set variables
i=1
word="dog"

#Read in template one line at the time, and replace variables (more
#natural (and efficient) way, thanks to Jonathan Leffler).
while read line
do
    eval echo "$line"
done < "./template.txt"

Output:

#sh script.sh
the number is 1
the word is dog

Get column index from column name in python pandas

For returning multiple column indices, I recommend using the pandas.Index method get_indexer, if you have unique labels:

df = pd.DataFrame({"pear": [1, 2, 3], "apple": [2, 3, 4], "orange": [3, 4, 5]})
df.columns.get_indexer(['pear', 'apple'])
# Out: array([0, 1], dtype=int64)

If you have non-unique labels in the index (columns only support unique labels) get_indexer_for. It takes the same args as get_indeder:

df = pd.DataFrame(
    {"pear": [1, 2, 3], "apple": [2, 3, 4], "orange": [3, 4, 5]}, 
    index=[0, 1, 1])
df.index.get_indexer_for([0, 1])
# Out: array([0, 1, 2], dtype=int64)

Both methods also support non-exact indexing with, f.i. for float values taking the nearest value with a tolerance. If two indices have the same distance to the specified label or are duplicates, the index with the larger index value is selected:

df = pd.DataFrame(
    {"pear": [1, 2, 3], "apple": [2, 3, 4], "orange": [3, 4, 5]},
    index=[0, .9, 1.1])
df.index.get_indexer([0, 1])
# array([ 0, -1], dtype=int64)

android.view.InflateException: Binary XML file: Error inflating class fragment

Is your NavigationDrawerFragment extending the android.support.v4.app.Fragment? In other words, are you importing the correct package?

import android.support.v4.app.Fragment;

Convert UIImage to NSData and convert back to UIImage in Swift?

Thanks. Helped me a lot. Converted to Swift 3 and worked

To save: let data = UIImagePNGRepresentation(image)

To load: let image = UIImage(data: data)

How to create a GUID/UUID in Python

This function is fully configurable and generates unique uid based on the format specified

eg:- [8, 4, 4, 4, 12] , this is the format mentioned and it will generate the following uuid

LxoYNyXe-7hbQ-caJt-DSdU-PDAht56cMEWi

 import random as r

 def generate_uuid():
        random_string = ''
        random_str_seq = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
        uuid_format = [8, 4, 4, 4, 12]
        for n in uuid_format:
            for i in range(0,n):
                random_string += str(random_str_seq[r.randint(0, len(random_str_seq) - 1)])
            if n != 12:
                random_string += '-'
        return random_string

How can I interrupt a running code in R with a keyboard command?

Control-C works, although depending on what the process is doing it might not take right away.

If you're on a unix based system, one thing I do is control-z to go back to the command line prompt and then issue a 'kill' to the process ID.

Command to get time in milliseconds

I just wanted to add to Alper's answer what I had to do to get this stuff working:

On Mac, you'll need brew install coreutils, so we can use gdate. Otherwise on Linux, it's just date. And this function will help you time commands without having to create temporary files or anything:

function timeit() {
    start=`gdate +%s%N`
    bash -c $1
    end=`gdate +%s%N`
    runtime=$(((end-start)/1000000000.0))
    echo " seconds"
}

And you can use it with a string:

timeit 'tsc --noEmit'

How do I kill all the processes in Mysql "show processlist"?

Only for mariaDB

It doesn't get simpler then this, Just execute this in mysql prompt.

kill USER username;

It will kill all process under provided username. because most of the people use same user for all purpose, it works!

I have tested this on MariaDB not sure about mysql.

How can I use a Python script in the command line without cd-ing to its directory? Is it the PYTHONPATH?

PYTHONPATH only affects import statements, not the top-level Python interpreter's lookup of python files given as arguments.

Needing PYTHONPATH to be set is not a great idea - as with anything dependent on environment variables, replicating things consistently across different machines gets tricky. Better is to use Python 'packages' which can be installed (using 'pip', or distutils) in system-dependent paths which Python already knows about.

Have a read of https://the-hitchhikers-guide-to-packaging.readthedocs.org/en/latest/ - 'The Hitchhiker's Guide to Packaging', and also http://docs.python.org/3/tutorial/modules.html - which explains PYTHONPATH and packages at a lower level.

Error message "unreported exception java.io.IOException; must be caught or declared to be thrown"

When the callee throws an exception i.e. void showfile() throws java.io.IOException the caller should handle it or throw it again.

And also learn naming conventions. A class name should start with a capital letter.

How to execute a remote command over ssh with arguments?

This is an example that works on the AWS Cloud. The scenario is that some machine that booted from autoscaling needs to perform some action on another server, passing the newly spawned instance DNS via SSH

# Get the public DNS of the current machine (AWS specific)
MY_DNS=`curl -s http://169.254.169.254/latest/meta-data/public-hostname`


ssh \
    -o StrictHostKeyChecking=no \
    -i ~/.ssh/id_rsa \
    [email protected] \
<< EOF
cd ~/
echo "Hey I was just SSHed by ${MY_DNS}"
run_other_commands
# Newline is important before final EOF!

EOF

What is the difference between require and require-dev sections in composer.json?

General rule is that you want packages from require-dev section only in development (dev) environments, for example local environment.

Packages in require-dev section are packages which help you debug app, run tests etc.

At staging and production environment you probably want only packages from require section.

But anyway you can run composer install --no-dev and composer update --no-dev on any environment, command will install only packages from required section not from require-dev, but probably you want to run this only at staging and production environments not on local.

Theoretically you can put all packages in require section and nothing will happened, but you don't want developing packages at production environment because of the following reasons :

  1. speed
  2. potential of expose some debuging info
  3. etc

Some good candidates for require-dev are :

"filp/whoops": "^2.0",
"fzaninotto/faker": "^1.4",
"mockery/mockery": "^1.0",
"nunomaduro/collision": "^2.0",
"phpunit/phpunit": "^7.0"

you can see what above packages are doing and you will see why you don't need them on production.

See more here : https://getcomposer.org/doc/04-schema.md

When to use the JavaScript MIME type application/javascript instead of text/javascript?

The problem with Javascript's MIME type is that there hasn't been a standard for years. Now we've got application/javascript as an official MIME type.

But actually, the MIME type doesn't matter at all, as the browser can determine the type itself. That's why the HTML5 specs state that the type="text/javascript" is no longer required.

Highlight all occurrence of a selected word?

In Normal mode:

:set hlsearch

Then search for a pattern with the command / in Normal mode, or <Ctrl>o followed by / in Insert mode. * in Normal mode will search for the next occurrence of the word under the cursor. The hlsearch option will highlight all of them if set. # will search for the previous occurrence of the word.

To remove the highlight of the previous search:

:nohlsearch

You might wish to map :nohlsearch<CR> to some convenient key.

Find all files in a directory with extension .txt in Python

A simple method by using for loop :

import os

dir = ["e","x","e"]

p = os.listdir('E:')  #path

for n in range(len(p)):
   name = p[n]
   myfile = [name[-3],name[-2],name[-1]]  #for .txt
   if myfile == dir :
      print(name)
   else:
      print("nops")

Though this can be made more generalised .

How to VueJS router-link active style

When you are creating the router, you can specify the linkExactActiveClass as a property to set the class that will be used for the active router link.

const routes = [
  { path: '/foo', component: Foo },
  { path: '/bar', component: Bar }
]

const router = new VueRouter({
  routes,
  linkActiveClass: "active", // active class for non-exact links.
  linkExactActiveClass: "active" // active class for *exact* links.
})

This is documented here.

Scripting Language vs Programming Language

Scripted languages

Scripting languages are interpreted within another program. JavaScript is embedded within a browser and interpreted by that browser.

Examples of scripting languages

  1. JavaScript
  2. Perl
  3. Python

Advantages of Scripting languages:

  1. Simple – Scripting languages are easier to write than programming language.

  2. Fewer Lines of Code (LOC)

Programmed languages

Programming languages like Java are compiled and not interpreted by another application in the same way.

Examples programming languages

  1. C
  2. C++ and
  3. Java

More Details

Getting a browser's name client-side

This code will return "browser" and "browserVersion"
Works on 95% of 80+ browsers

var geckobrowsers;
var browser = "";
var browserVersion = 0;
var agent = navigator.userAgent + " ";
if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0" && agent.indexOf("like Gecko") != -1){
    geckobrowsers = agent.substring(agent.indexOf("like Gecko")+10).substring(agent.substring(agent.indexOf("like Gecko")+10).indexOf(") ")+2).replace("LG Browser", "LGBrowser").replace("360SE", "360SE/");
    for(i = 0; i < 1; i++){
        geckobrowsers = geckobrowsers.replace(geckobrowsers.substring(geckobrowsers.indexOf("("), geckobrowsers.indexOf(")")+1), "");
    }
    geckobrowsers = geckobrowsers.split(" ");
    for(i = 0; i < geckobrowsers.length; i++){
        if(geckobrowsers[i].indexOf("/") == -1)geckobrowsers[i] = "Chrome";
        if(geckobrowsers[i].indexOf("/") != -1)geckobrowsers[i] = geckobrowsers[i].substring(0, geckobrowsers[i].indexOf("/"));
    }
    if(geckobrowsers.length < 4){
        browser = geckobrowsers[0];
    } else {
        for(i = 0; i < geckobrowsers.length; i++){
            if(geckobrowsers[i].indexOf("Chrome") == -1 && geckobrowsers[i].indexOf("Safari") == -1 && geckobrowsers[i].indexOf("Mobile") == -1 && geckobrowsers[i].indexOf("Version") == -1)browser = geckobrowsers[i];
        }
    }
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0" && agent.indexOf("Gecko/") != -1){
    browser = agent.substring(agent.substring(agent.indexOf("Gecko/")+6).indexOf(" ") + agent.indexOf("Gecko/")+6).substring(0, agent.substring(agent.substring(agent.indexOf("Gecko/")+6).indexOf(" ") + agent.indexOf("Gecko/")+6).indexOf("/"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0" && agent.indexOf("Clecko/") != -1){
    browser = agent.substring(agent.substring(agent.indexOf("Clecko/")+7).indexOf(" ") + agent.indexOf("Clecko/")+7).substring(0, agent.substring(agent.substring(agent.indexOf("Clecko/")+7).indexOf(" ") + agent.indexOf("Clecko/")+7).indexOf("/"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "5.0"){
    browser = agent.substring(agent.indexOf("(")+1, agent.indexOf(";"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "4.0" && agent.indexOf(")")+1 == agent.length-1){
    browser = agent.substring(agent.indexOf("(")+1, agent.indexOf(")")).split("; ")[agent.substring(agent.indexOf("(")+1, agent.indexOf(")")).split("; ").length-1];
} else if(agent.substring(agent.indexOf("Mozilla/")+8, agent.indexOf(" ")) == "4.0" && agent.indexOf(")")+1 != agent.length-1){
    if(agent.substring(agent.indexOf(") ")+2).indexOf("/") != -1)browser = agent.substring(agent.indexOf(") ")+2, agent.indexOf(") ")+2+agent.substring(agent.indexOf(") ")+2).indexOf("/"));
    if(agent.substring(agent.indexOf(") ")+2).indexOf("/") == -1)browser = agent.substring(agent.indexOf(") ")+2, agent.indexOf(") ")+2+agent.substring(agent.indexOf(") ")+2).indexOf(" "));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else if(agent.substring(0, 6) == "Opera/"){
    browser = "Opera";
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
    if(agent.substring(agent.indexOf("(")+1).indexOf(";") != -1)os = agent.substring(agent.indexOf("(")+1, agent.indexOf("(")+1+agent.substring(agent.indexOf("(")+1).indexOf(";"));
    if(agent.substring(agent.indexOf("(")+1).indexOf(";") == -1)os = agent.substring(agent.indexOf("(")+1, agent.indexOf("(")+1+agent.substring(agent.indexOf("(")+1).indexOf(")"));
} else if(agent.substring(0, agent.indexOf("/")) != "Mozilla" && agent.substring(0, agent.indexOf("/")) != "Opera"){
    browser = agent.substring(0, agent.indexOf("/"));
    browserVersion = agent.substring(agent.indexOf(browser)+browser.length+1, agent.indexOf(browser)+browser.length+1+agent.substring(agent.indexOf(browser)+browser.length+1).indexOf(" "));
} else {
    browser = agent;
}
alert(browser + " v" + browserVersion);

Laravel: Error [PDOException]: Could not Find Driver in PostgreSQL

In Windows 8 PC with Laragon 3.4.0 180809, I faced the same issue. It happened in my case because I updated Laragon and it added a new version of PHP. So in laragon/bin/php/ I actually had two directories:

  • php-7.1.20-Win32-VC14-x64
  • php-7.1.7-Win32-VC14-x64

I added 7.1.20 into my PATH variable. But in my Command Console, running php --ini was showing that the path actually was fetching from the older one: php-7.1.7-Win32-VC14-x64. So I deleted the old one (for safety, I put it in Recycle Bin). But Laragon failed to start after that.

So, in laragaon/etc/apache2/mod_php.conf, I changed the path to the latest PHP version. Then restarted Laragon and the issue is resolved.

Reference: How to add another PHP version - Laragon Forum

Thread-safe List<T> property

Looking at the original sample one may guess that the intention was to be able to simply replace the list with the new one. The setter on the property tells us about it.

The Micrisoft's Thread-Safe Collections are for safely adding and removing items from collection. But if in the application logic you are intending to replace the collection with the new one, one may guess, again, that the adding and deleting functionality of the List is not required.

If this is the case then, the simple answer would be to use IReadOnlyList interface:

 private IReadOnlyList<T> _readOnlyList = new List<T>();

    private IReadOnlyList<T> MyT
    {
       get { return _readOnlyList; }
       set { _readOnlyList = value; }
    }

One doesn't need to use any locking in this situation because there is no way to modify the collection. If in the setter the "_readOnlyList = value;" will be replaced by something more complicated then the lock could be required.

Finding whether a point lies inside a rectangle or not

How is the rectangle represented? Three points? Four points? Point, sides and angle? Two points and a side? Something else? Without knowing that, any attempts to answer your question will have only purely academic value.

In any case, for any convex polygon (including rectangle) the test is very simple: check each edge of the polygon, assuming each edge is oriented in counterclockwise direction, and test whether the point lies to the left of the edge (in the left-hand half-plane). If all edges pass the test - the point is inside. If at least one fails - the point is outside.

In order to test whether the point (xp, yp) lies on the left-hand side of the edge (x1, y1) - (x2, y2), you just need to calculate

D = (x2 - x1) * (yp - y1) - (xp - x1) * (y2 - y1)

If D > 0, the point is on the left-hand side. If D < 0, the point is on the right-hand side. If D = 0, the point is on the line.


The previous version of this answer described a seemingly different version of left-hand side test (see below). But it can be easily shown that it calculates the same value.

... In order to test whether the point (xp, yp) lies on the left-hand side of the edge (x1, y1) - (x2, y2), you need to build the line equation for the line containing the edge. The equation is as follows

A * x + B * y + C = 0

where

A = -(y2 - y1)
B = x2 - x1
C = -(A * x1 + B * y1)

Now all you need to do is to calculate

D = A * xp + B * yp + C

If D > 0, the point is on the left-hand side. If D < 0, the point is on the right-hand side. If D = 0, the point is on the line.

However, this test, again, works for any convex polygon, meaning that it might be too generic for a rectangle. A rectangle might allow a simpler test... For example, in a rectangle (or in any other parallelogram) the values of A and B have the same magnitude but different signs for opposing (i.e. parallel) edges, which can be exploited to simplify the test.

Calculate correlation for more than two variables?

You can also calculate correlations for all variables but exclude selected ones, for example:

mtcars <- data.frame(mtcars)
# here we exclude gear and carb variables
cors <- cor(subset(mtcars, select = c(-gear,-carb)))

Also, to calculate correlation between each variable and one column you can use sapply()

# sapply effectively calls the corelation function for each column of mtcars and mtcars$mpg
cors2 <- sapply(mtcars, cor, y=mtcars$mpg)

Android ListView selected item stay highlighted

One way you can do this, is to Keep track of the current selected position in your activity:

@Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int position,
            long arg3) {
        currentPosition = position
        lv_cli.notifyDataSetChanged();
    }

Now, be sure you assign an ID to the parent layout (linearLayout, boxLayout, relativeLayout, .. Whatever you prefer) of your list item.

Then in your ListView you can do something Like this:

layoutBackground = (LinearLayout) convertView.findViewById(R.id.layout_background);

if (YourActivity.this.currentPosition == position) {
    layoutBackground.setBackgroundColor(YourActivity.this.getResources().getColor(R.color.hilight_color));
} else{
    layoutBackground.setBackgroundResource(R.drawable.list_item_drawable);
}

Basically, you just set the hilight color to the layout as a background when it equals your current selected position. Notice how I set a drawable background resource when the item is not selected. This could be in your case different (since you posted no code). In my case, this drawable is a selector which makes sure the item is hi-lighted when pressed.

NOTE: This simple code doesn't use a view-holder, but I really recommend using one.

How to Convert JSON object to Custom C# object?

The following 2 examples make use of either

  1. JavaScriptSerializer under System.Web.Script.Serialization Or
  2. Json.Decode under System.Web.Helpers

Example 1: using System.Web.Script.Serialization

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Web.Script.Serialization;

namespace Tests
{
    [TestClass]
    public class JsonTests
    {
        [TestMethod]
        public void Test()
        {
            var json = "{\"user\":{\"name\":\"asdf\",\"teamname\":\"b\",\"email\":\"c\",\"players\":[\"1\",\"2\"]}}";
            JavaScriptSerializer serializer = new JavaScriptSerializer();
            dynamic jsonObject = serializer.Deserialize<dynamic>(json);

            dynamic x = jsonObject["user"]; // result is Dictionary<string,object> user with fields name, teamname, email and players with their values
            x = jsonObject["user"]["name"]; // result is asdf
            x = jsonObject["user"]["players"]; // result is object[] players with its values
        }
    }
}

Usage: JSON object to Custom C# object

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Web.Script.Serialization;
using System.Linq;

namespace Tests
{
    [TestClass]
    public class JsonTests
    {
        [TestMethod]
        public void TestJavaScriptSerializer()
        {
            var json = "{\"user\":{\"name\":\"asdf\",\"teamname\":\"b\",\"email\":\"c\",\"players\":[\"1\",\"2\"]}}";
            User user = new User(json);
            Console.WriteLine("Name : " + user.name);
            Console.WriteLine("Teamname : " + user.teamname);
            Console.WriteLine("Email : " + user.email);
            Console.WriteLine("Players:");
            foreach (var player in user.players)
                Console.WriteLine(player);
        }
    }

    public class User {
        public User(string json) {
            JavaScriptSerializer serializer = new JavaScriptSerializer();
            var jsonObject = serializer.Deserialize<dynamic>(json);
            name = (string)jsonObject["user"]["name"];
            teamname = (string)jsonObject["user"]["teamname"];
            email = (string)jsonObject["user"]["email"];
            players = jsonObject["user"]["players"];
        }

        public string name { get; set; }
        public string teamname { get; set; }
        public string email { get; set; }
        public Array players { get; set; }
    }
}

Example 2: using System.Web.Helpers

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Web.Helpers;

namespace Tests
{
    [TestClass]
    public class JsonTests
    {
        [TestMethod]
        public void TestJsonDecode()
        {
            var json = "{\"user\":{\"name\":\"asdf\",\"teamname\":\"b\",\"email\":\"c\",\"players\":[\"1\",\"2\"]}}";
            dynamic jsonObject = Json.Decode(json);

            dynamic x = jsonObject.user; // result is dynamic json object user with fields name, teamname, email and players with their values
            x = jsonObject.user.name; // result is asdf
            x = jsonObject.user.players; // result is dynamic json array players with its values
        }
    }
}

Usage: JSON object to Custom C# object

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Web.Helpers;
using System.Linq;

namespace Tests
{
    [TestClass]
    public class JsonTests
    {
        [TestMethod]
        public void TestJsonDecode()
        {
            var json = "{\"user\":{\"name\":\"asdf\",\"teamname\":\"b\",\"email\":\"c\",\"players\":[\"1\",\"2\"]}}";
            User user = new User(json);
            Console.WriteLine("Name : " + user.name);
            Console.WriteLine("Teamname : " + user.teamname);
            Console.WriteLine("Email : " + user.email);
            Console.WriteLine("Players:");
            foreach (var player in user.players)
                Console.WriteLine(player);
        }
    }

    public class User {
        public User(string json) {
            var jsonObject = Json.Decode(json);
            name = (string)jsonObject.user.name;
            teamname = (string)jsonObject.user.teamname;
            email = (string)jsonObject.user.email;
            players = (DynamicJsonArray) jsonObject.user.players;
        }

        public string name { get; set; }
        public string teamname { get; set; }
        public string email { get; set; }
        public Array players { get; set; }
    }
}

This code requires adding System.Web.Helpers namespace found in,

%ProgramFiles%\Microsoft ASP.NET\ASP.NET Web Pages{VERSION}\Assemblies\System.Web.Helpers.dll

Or

%ProgramFiles(x86)%\Microsoft ASP.NET\ASP.NET Web Pages{VERSION}\Assemblies\System.Web.Helpers.dll

Hope this helps!

How to disable gradle 'offline mode' in android studio?

Edit. As noted in the comments, this is no longer working with the latest Android Studio releases.

The latest Android studio seems to only reference to "Offline mode" via the keymap, but toggling this does not seem to change anything anymore.


In Android Studio open the settings and search for offline it will find the Gradle category which contains Offline work. You can disable it there.

Gradle Offline work

Is there a destructor for Java?

Just thinking about the original question... which, I think we can conclude from all the other learned answers, and also from Bloch's essential Effective Java, item 7, "Avoid finalizers", seeks the solution to a legitimate question in a manner which is inappropriate to the Java language...:

... wouldn't a pretty obvious solution to do what the OP actually wants be to keep all your objects which need to be reset in a sort of "playpen", to which all other non-resettable objects have references only through some sort of accessor object...

And then when you need to "reset" you disconnect the existing playpen and make a new one: all the web of objects in the playpen is cast adrift, never to return, and one day to be collected by the GC.

If any of these objects are Closeable (or not, but have a close method) you could put them in a Bag in the playpen as they are created (and possibly opened), and the last act of the accessor before cutting off the playpen would be to go through all the Closeables closing them... ?

The code would probably look something like this:

accessor.getPlaypen().closeCloseables();
accessor.setPlaypen( new Playpen() );

closeCloseables would probably be a blocking method, probably involving a latch (e.g. CountdownLatch), to deal with (and wait as appropriate for) any Runnables/Callables in any threads specific to the Playpen to be ended as appropriate, in particular in the JavaFX thread.

How to apply Hovering on html area tag?

for complete this script , the function for draw circle ,

    function drawCircle(coordon)
    {
        var coord = coordon.split(',');

        var c = document.getElementById("myCanvas");
        var hdc = c.getContext("2d");
        hdc.beginPath();

        hdc.arc(coord[0], coord[1], coord[2], 0, 2 * Math.PI);
        hdc.stroke();
    }

HTTP Status 405 - HTTP method POST is not supported by this URL java servlet

if you are using tomcat you may try this

<servlet-mapping>

    <http-method>POST</http-method>

</servlet-mapping>

in addition to <servlet-name> and <url-mapping>

Pandas percentage of total with groupby

For conciseness I'd use the SeriesGroupBy:

In [11]: c = df.groupby(['state', 'office_id'])['sales'].sum().rename("count")

In [12]: c
Out[12]:
state  office_id
AZ     2            925105
       4            592852
       6            362198
CA     1            819164
       3            743055
       5            292885
CO     1            525994
       3            338378
       5            490335
WA     2            623380
       4            441560
       6            451428
Name: count, dtype: int64

In [13]: c / c.groupby(level=0).sum()
Out[13]:
state  office_id
AZ     2            0.492037
       4            0.315321
       6            0.192643
CA     1            0.441573
       3            0.400546
       5            0.157881
CO     1            0.388271
       3            0.249779
       5            0.361949
WA     2            0.411101
       4            0.291196
       6            0.297703
Name: count, dtype: float64

For multiple groups you have to use transform (using Radical's df):

In [21]: c =  df.groupby(["Group 1","Group 2","Final Group"])["Numbers I want as percents"].sum().rename("count")

In [22]: c / c.groupby(level=[0, 1]).transform("sum")
Out[22]:
Group 1  Group 2  Final Group
AAHQ     BOSC     OWON           0.331006
                  TLAM           0.668994
         MQVF     BWSI           0.288961
                  FXZM           0.711039
         ODWV     NFCH           0.262395
...
Name: count, dtype: float64

This seems to be slightly more performant than the other answers (just less than twice the speed of Radical's answer, for me ~0.08s).

filtering a list using LINQ

EDIT: better yet, do it like that:

var filteredProjects = 
    projects.Where(p => filteredTags.All(tag => p.Tags.Contains(tag)));

EDIT2: Honestly, I don't know which one is better, so if performance is not critical, choose the one you think is more readable. If it is, you'll have to benchmark it somehow.


Probably Intersect is the way to go:

void Main()
{
    var projects = new List<Project>();
    projects.Add(new Project { Name = "Project1", Tags = new int[] { 2, 5, 3, 1 } });
    projects.Add(new Project { Name = "Project2", Tags = new int[] { 1, 4, 7 } });
    projects.Add(new Project { Name = "Project3", Tags = new int[] { 1, 7, 12, 3 } });

    var filteredTags = new int []{ 1, 3 };
    var filteredProjects = projects.Where(p => p.Tags.Intersect(filteredTags).Count() == filteredTags.Length);  
}


class Project {
    public string Name;
    public int[] Tags;
}

Although that seems a little ugly at first. You may first apply Distinct to filteredTags if you aren't sure whether they are all unique in the list, otherwise the counts comparison won't work as expected.

TypeScript enum to object array

I use

Object.entries(GoalProgressMeasurement).filter(e => !isNaN(e[0]as any)).map(e => ({ name: e[1], id: e[0] }));

A simple 1 line that does the job.

It does the job in 3 simple steps
- Loads the combination of keys & values using Object.entries.
- Filters out the non numbers (since typescript generates the values for reverse lookup).
- Then we map it to the array object we like.

Angular2 - TypeScript : Increment a number after timeout in AppComponent

This is not valid TypeScript code. You can not have method invocations in the body of a class.

// INVALID CODE
export class AppComponent {
  public n: number = 1;
  setTimeout(function() {
    n = n + 10;
  }, 1000);
}

Instead move the setTimeout call to the constructor of the class. Additionally, use the arrow function => to gain access to this.

export class AppComponent {
  public n: number = 1;

  constructor() {
    setTimeout(() => {
      this.n = this.n + 10;
    }, 1000);
  }

}

In TypeScript, you can only refer to class properties or methods via this. That's why the arrow function => is important.

Sorting string array in C#

This code snippet is working properly enter image description here

Write to custom log file from a Bash script

If you see the man page of logger:

$ man logger

LOGGER(1) BSD General Commands Manual LOGGER(1)

NAME logger — a shell command interface to the syslog(3) system log module

SYNOPSIS logger [-isd] [-f file] [-p pri] [-t tag] [-u socket] [message ...]

DESCRIPTION Logger makes entries in the system log. It provides a shell command interface to the syslog(3) system log module.

It Clearly says that it will log to system log. If you want to log to file, you can use ">>" to redirect to log file.

using wildcards in LDAP search filters/queries

A filter argument with a trailing * can be evaluated almost instantaneously via an index lookup. A leading * implies a sequential search through the index, so it is O(N). It will take ages.

I suggest you reconsider the requirement.

Python - Join with newline

The console is printing the representation, not the string itself.

If you prefix with print, you'll get what you expect.

See this question for details about the difference between a string and the string's representation. Super-simplified, the representation is what you'd type in source code to get that string.

Display text on MouseOver for image in html

You can use CSS hover in combination with an image background.

CSS

   .image
{
    background:url(images/back.png);
    height:100px;
    width:100px;
    display: block;
    float:left;
}

.image  a {
    display: none;
}

.image  a:hover {
    display: block;
}

HTML

<div class="image"><a href="#">Text you want on mouseover</a></div>

Remove/ truncate leading zeros by javascript/jquery

I got this solution for truncating leading zeros(number or any string) in javascript:

<script language="JavaScript" type="text/javascript">
<!--
function trimNumber(s) {
  while (s.substr(0,1) == '0' && s.length>1) { s = s.substr(1,9999); }
  return s;
}

var s1 = '00123';
var s2 = '000assa';
var s3 = 'assa34300';
var s4 = 'ssa';
var s5 = '121212000';

alert(s1 + '=' + trimNumber(s1));
alert(s2 + '=' + trimNumber(s2));
alert(s3 + '=' + trimNumber(s3));
alert(s4 + '=' + trimNumber(s4));
alert(s5 + '=' + trimNumber(s5));
// end hiding contents -->
</script>

PHP "pretty print" json_encode

Here's a function to pretty up your json: pretty_json

Find child element in AngularJS directive

jQlite (angular's "jQuery" port) doesn't support lookup by classes.

One solution would be to include jQuery in your app.

Another is using QuerySelector or QuerySelectorAll:

link: function(scope, element, attrs) {
   console.log(element[0].querySelector('.list-scrollable'))
}

We use the first item in the element array, which is the HTML element. element.eq(0) would yield the same.

FIDDLE

CentOS: Copy directory to another directory

This works for me.

cp -r /home/server/folder/test/. /home/server

How to get current SIM card number in Android?

Getting the Phone Number, IMEI, and SIM Card ID

TelephonyManager tm = (TelephonyManager) 
            getSystemService(Context.TELEPHONY_SERVICE);        

For SIM card, use the getSimSerialNumber()

    //---get the SIM card ID---
    String simID = tm.getSimSerialNumber();
    if (simID != null)
        Toast.makeText(this, "SIM card ID: " + simID, 
        Toast.LENGTH_LONG).show();

Phone number of your phone, use the getLine1Number() (some device's dont return the phone number)

    //---get the phone number---
    String telNumber = tm.getLine1Number();
    if (telNumber != null)        
        Toast.makeText(this, "Phone number: " + telNumber, 
        Toast.LENGTH_LONG).show();

IMEI number of the phone, use the getDeviceId()

    //---get the IMEI number---
    String IMEI = tm.getDeviceId();
    if (IMEI != null)        
        Toast.makeText(this, "IMEI number: " + IMEI, 
        Toast.LENGTH_LONG).show();

Permissions needed

<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

Create a function with optional call variables

I don't think your question is very clear, this code assumes that if you're going to include the -domain parameter, it's always 'named' (i.e. dostuff computername arg2 -domain domain); this also makes the computername parameter mandatory.

Function DoStuff(){
    param(
        [Parameter(Mandatory=$true)][string]$computername,
        [Parameter(Mandatory=$false)][string]$arg2,
        [Parameter(Mandatory=$false)][string]$domain
    )
    if(!($domain)){
        $domain = 'domain1'
    }
    write-host $domain
    if($arg2){
        write-host "arg2 present... executing script block"
    }
    else{
        write-host "arg2 missing... exiting or whatever"
    }
}

Fastest method of screen capturing on Windows

i myself do it with directx and think it's as fast as you would want it to be. i don't have a quick code sample, but i found this which should be useful. the directx11 version should not differ a lot, directx9 maybe a little more, but thats the way to go

How can I check if a string contains ANY letters from the alphabet?

You can use islower() on your string to see if it contains some lowercase letters (amongst other characters). or it with isupper() to also check if contains some uppercase letters:

below: letters in the string: test yields true

>>> z = "(555) 555 - 5555 ext. 5555"
>>> z.isupper() or z.islower()
True

below: no letters in the string: test yields false.

>>> z= "(555).555-5555"
>>> z.isupper() or z.islower()
False
>>> 

Not to be mixed up with isalpha() which returns True only if all characters are letters, which isn't what you want.

Note that Barm's answer completes mine nicely, since mine doesn't handle the mixed case well.

PHP substring extraction. Get the string before the first '/' or the whole string

The most efficient solution is the strtok function:

strtok($mystring, '/')

NOTE: In case of more than one character to split with the results may not meet your expectations e.g. strtok("somethingtosplit", "to") returns s because it is splitting by any single character from the second argument (in this case o is used).

@friek108 thanks for pointing that out in your comment.

For example:

$mystring = 'home/cat1/subcat2/';
$first = strtok($mystring, '/');
echo $first; // home

and

$mystring = 'home';
$first = strtok($mystring, '/');
echo $first; // home

Delayed function calls

It's indeed a very bad design, let alone singleton by itself is bad design.

However, if you really do need to delay execution, here's what you may do:

BackgroundWorker barInvoker = new BackgroundWorker();
barInvoker.DoWork += delegate
    {
        Thread.Sleep(TimeSpan.FromSeconds(1));
        bar();
    };
barInvoker.RunWorkerAsync();

This will, however, invoke bar() on a separate thread. If you need to call bar() in the original thread you might need to move bar() invocation to RunWorkerCompleted handler or do a bit of hacking with SynchronizationContext.

How to iterate over the files of a certain directory, in Java?

Here is an example that lists all the files on my desktop. you should change the path variable to your path.

Instead of printing the file's name with System.out.println, you should place your own code to operate on the file.

public static void main(String[] args) {
    File path = new File("c:/documents and settings/Zachary/desktop");

    File [] files = path.listFiles();
    for (int i = 0; i < files.length; i++){
        if (files[i].isFile()){ //this line weeds out other directories/folders
            System.out.println(files[i]);
        }
    }
}

How to set x axis values in matplotlib python?

The scaling on your example figure is a bit strange but you can force it by plotting the index of each x-value and then setting the ticks to the data points:

import matplotlib.pyplot as plt
x = [0.00001,0.001,0.01,0.1,0.5,1,5]
# create an index for each tick position
xi = list(range(len(x)))
y = [0.945,0.885,0.893,0.9,0.996,1.25,1.19]
plt.ylim(0.8,1.4)
# plot the index for the x-values
plt.plot(xi, y, marker='o', linestyle='--', color='r', label='Square') 
plt.xlabel('x')
plt.ylabel('y') 
plt.xticks(xi, x)
plt.title('compare')
plt.legend() 
plt.show()

How to change Angular CLI favicon

Move favicon.ico to your assets and then to img folder, and after that only change your icon link tag in header. It helps me when favicon was not displayed at all.

Java - Change int to ascii

The most simple way is using type casting:

public char toChar(int c) {
    return (char)c;
}

How to remove a class from elements in pure JavaScript?

It's 2021... keep it simple.

Times have changed and now the cleanest and most readable way to do this is:

Array.from(document.querySelectorAll('widget hover')).forEach((el) => el.classList.remove('hover'));

If you can't support arrow functions then just convert it like this:

Array.from(document.querySelectorAll('widget hover')).forEach(function(el) { 
    el.classList.remove('hover');
});

Additionally if you need to support extremely old browsers then use a polyfil for the forEach and Array.from and move on with your life.

How to Set OnClick attribute with value containing function in ie8?

your best bet is to use a javascript framework like jquery or prototype, but, failing that, you should use:

if (foo.addEventListener) 
    foo.addEventListener('click',doit,false); //everything else    
else if (foo.attachEvent)
    foo.attachEvent('onclick',doit);  //IE only

edit:

also, your function is a little off. it should be

var doit = function(){
    alert('hello world!');
}

plain count up timer in javascript

Fiddled around with the Bakudan's code and other code in stackoverflow to get everything in one.

Update #1 : Added more options. Now Start, pause, resume, reset and restart. Mix the functions to get desired results.

Update #2 : Edited out previously used JQuery codes for pure JS and added as code snippet.

For previous Jquery based fiddle version : https://jsfiddle.net/wizajay/rro5pna3/305/

_x000D_
_x000D_
var Clock = {_x000D_
  totalSeconds: 0,_x000D_
  start: function () {_x000D_
    if (!this.interval) {_x000D_
        var self = this;_x000D_
        function pad(val) { return val > 9 ? val : "0" + val; }_x000D_
        this.interval = setInterval(function () {_x000D_
          self.totalSeconds += 1;_x000D_
_x000D_
          document.getElementById("min").innerHTML = pad(Math.floor(self.totalSeconds / 60 % 60));_x000D_
          document.getElementById("sec").innerHTML = pad(parseInt(self.totalSeconds % 60));_x000D_
        }, 1000);_x000D_
    }_x000D_
  },_x000D_
_x000D_
  reset: function () {_x000D_
    Clock.totalSeconds = null; _x000D_
    clearInterval(this.interval);_x000D_
    document.getElementById("min").innerHTML = "00";_x000D_
    document.getElementById("sec").innerHTML = "00";_x000D_
    delete this.interval;_x000D_
  },_x000D_
  pause: function () {_x000D_
    clearInterval(this.interval);_x000D_
    delete this.interval;_x000D_
  },_x000D_
_x000D_
  resume: function () {_x000D_
    this.start();_x000D_
  },_x000D_
_x000D_
  restart: function () {_x000D_
     this.reset();_x000D_
     Clock.start();_x000D_
  }_x000D_
};_x000D_
_x000D_
_x000D_
document.getElementById("startButton").addEventListener("click", function () { Clock.start(); });_x000D_
document.getElementById("pauseButton").addEventListener("click", function () { Clock.pause(); });_x000D_
document.getElementById("resumeButton").addEventListener("click", function () { Clock.resume(); });_x000D_
document.getElementById("resetButton").addEventListener("click", function () { Clock.reset(); });_x000D_
document.getElementById("restartButton").addEventListener("click", function () { Clock.restart(); });
_x000D_
<span id="min">00</span>:<span id="sec">00</span>_x000D_
_x000D_
<input id="startButton" type="button" value="Start">_x000D_
<input id="pauseButton" type="button" value="Pause">_x000D_
<input id="resumeButton" type="button" value="Resume">_x000D_
<input id="resetButton" type="button" value="Reset">_x000D_
<input id="restartButton" type="button" value="Restart">
_x000D_
_x000D_
_x000D_

How can I Convert HTML to Text in C#?

Just a note about the HtmlAgilityPack for posterity. The project contains an example of parsing text to html, which, as noted by the OP, does not handle whitespace at all like anyone writing HTML would envisage. There are full-text rendering solutions out there, noted by others to this question, which this is not (it cannot even handle tables in its current form), but it is lightweight and fast, which is all I wanted for creating a simple text version of HTML emails.

using System.IO;
using System.Text.RegularExpressions;
using HtmlAgilityPack;

//small but important modification to class https://github.com/zzzprojects/html-agility-pack/blob/master/src/Samples/Html2Txt/HtmlConvert.cs
public static class HtmlToText
{

    public static string Convert(string path)
    {
        HtmlDocument doc = new HtmlDocument();
        doc.Load(path);
        return ConvertDoc(doc);
    }

    public static string ConvertHtml(string html)
    {
        HtmlDocument doc = new HtmlDocument();
        doc.LoadHtml(html);
        return ConvertDoc(doc);
    }

    public static string ConvertDoc (HtmlDocument doc)
    {
        using (StringWriter sw = new StringWriter())
        {
            ConvertTo(doc.DocumentNode, sw);
            sw.Flush();
            return sw.ToString();
        }
    }

    internal static void ConvertContentTo(HtmlNode node, TextWriter outText, PreceedingDomTextInfo textInfo)
    {
        foreach (HtmlNode subnode in node.ChildNodes)
        {
            ConvertTo(subnode, outText, textInfo);
        }
    }
    public static void ConvertTo(HtmlNode node, TextWriter outText)
    {
        ConvertTo(node, outText, new PreceedingDomTextInfo(false));
    }
    internal static void ConvertTo(HtmlNode node, TextWriter outText, PreceedingDomTextInfo textInfo)
    {
        string html;
        switch (node.NodeType)
        {
            case HtmlNodeType.Comment:
                // don't output comments
                break;
            case HtmlNodeType.Document:
                ConvertContentTo(node, outText, textInfo);
                break;
            case HtmlNodeType.Text:
                // script and style must not be output
                string parentName = node.ParentNode.Name;
                if ((parentName == "script") || (parentName == "style"))
                {
                    break;
                }
                // get text
                html = ((HtmlTextNode)node).Text;
                // is it in fact a special closing node output as text?
                if (HtmlNode.IsOverlappedClosingElement(html))
                {
                    break;
                }
                // check the text is meaningful and not a bunch of whitespaces
                if (html.Length == 0)
                {
                    break;
                }
                if (!textInfo.WritePrecedingWhiteSpace || textInfo.LastCharWasSpace)
                {
                    html= html.TrimStart();
                    if (html.Length == 0) { break; }
                    textInfo.IsFirstTextOfDocWritten.Value = textInfo.WritePrecedingWhiteSpace = true;
                }
                outText.Write(HtmlEntity.DeEntitize(Regex.Replace(html.TrimEnd(), @"\s{2,}", " ")));
                if (textInfo.LastCharWasSpace = char.IsWhiteSpace(html[html.Length - 1]))
                {
                    outText.Write(' ');
                }
                    break;
            case HtmlNodeType.Element:
                string endElementString = null;
                bool isInline;
                bool skip = false;
                int listIndex = 0;
                switch (node.Name)
                {
                    case "nav":
                        skip = true;
                        isInline = false;
                        break;
                    case "body":
                    case "section":
                    case "article":
                    case "aside":
                    case "h1":
                    case "h2":
                    case "header":
                    case "footer":
                    case "address":
                    case "main":
                    case "div":
                    case "p": // stylistic - adjust as you tend to use
                        if (textInfo.IsFirstTextOfDocWritten)
                        {
                            outText.Write("\r\n");
                        }
                        endElementString = "\r\n";
                        isInline = false;
                        break;
                    case "br":
                        outText.Write("\r\n");
                        skip = true;
                        textInfo.WritePrecedingWhiteSpace = false;
                        isInline = true;
                        break;
                    case "a":
                        if (node.Attributes.Contains("href"))
                        {
                            string href = node.Attributes["href"].Value.Trim();
                            if (node.InnerText.IndexOf(href, StringComparison.InvariantCultureIgnoreCase)==-1)
                            {
                                endElementString =  "<" + href + ">";
                            }  
                        }
                        isInline = true;
                        break;
                    case "li": 
                        if(textInfo.ListIndex>0)
                        {
                            outText.Write("\r\n{0}.\t", textInfo.ListIndex++); 
                        }
                        else
                        {
                            outText.Write("\r\n*\t"); //using '*' as bullet char, with tab after, but whatever you want eg "\t->", if utf-8 0x2022
                        }
                        isInline = false;
                        break;
                    case "ol": 
                        listIndex = 1;
                        goto case "ul";
                    case "ul": //not handling nested lists any differently at this stage - that is getting close to rendering problems
                        endElementString = "\r\n";
                        isInline = false;
                        break;
                    case "img": //inline-block in reality
                        if (node.Attributes.Contains("alt"))
                        {
                            outText.Write('[' + node.Attributes["alt"].Value);
                            endElementString = "]";
                        }
                        if (node.Attributes.Contains("src"))
                        {
                            outText.Write('<' + node.Attributes["src"].Value + '>');
                        }
                        isInline = true;
                        break;
                    default:
                        isInline = true;
                        break;
                }
                if (!skip && node.HasChildNodes)
                {
                    ConvertContentTo(node, outText, isInline ? textInfo : new PreceedingDomTextInfo(textInfo.IsFirstTextOfDocWritten){ ListIndex = listIndex });
                }
                if (endElementString != null)
                {
                    outText.Write(endElementString);
                }
                break;
        }
    }
}
internal class PreceedingDomTextInfo
{
    public PreceedingDomTextInfo(BoolWrapper isFirstTextOfDocWritten)
    {
        IsFirstTextOfDocWritten = isFirstTextOfDocWritten;
    }
    public bool WritePrecedingWhiteSpace {get;set;}
    public bool LastCharWasSpace { get; set; }
    public readonly BoolWrapper IsFirstTextOfDocWritten;
    public int ListIndex { get; set; }
}
internal class BoolWrapper
{
    public BoolWrapper() { }
    public bool Value { get; set; }
    public static implicit operator bool(BoolWrapper boolWrapper)
    {
        return boolWrapper.Value;
    }
    public static implicit operator BoolWrapper(bool boolWrapper)
    {
        return new BoolWrapper{ Value = boolWrapper };
    }
}

As an example, the following HTML code...

<!DOCTYPE HTML>
<html>
    <head>
    </head>
    <body>
        <header>
            Whatever Inc.
        </header>
        <main>
            <p>
                Thanks for your enquiry. As this is the 1<sup>st</sup> time you have contacted us, we would like to clarify a few things:
            </p>
            <ol>
                <li>
                    Please confirm this is your email by replying.
                </li>
                <li>
                    Then perform this step.
                </li>
            </ol>
            <p>
                Please solve this <img alt="complex equation" src="http://upload.wikimedia.org/wikipedia/commons/8/8d/First_Equation_Ever.png"/>. Then, in any order, could you please:
            </p>
            <ul>
                <li>
                    a point.
                </li>
                <li>
                    another point, with a <a href="http://en.wikipedia.org/wiki/Hyperlink">hyperlink</a>.
                </li>
            </ul>
            <p>
                Sincerely,
            </p>
            <p>
                The whatever.com team
            </p>
        </main>
        <footer>
            Ph: 000 000 000<br/>
            mail: whatever st
        </footer>
    </body>
</html>

...will be transformed into:

Whatever Inc. 


Thanks for your enquiry. As this is the 1st time you have contacted us, we would like to clarify a few things: 

1.  Please confirm this is your email by replying. 
2.  Then perform this step. 

Please solve this [complex equation<http://upload.wikimedia.org/wikipedia/commons/8/8d/First_Equation_Ever.png>]. Then, in any order, could you please: 

*   a point. 
*   another point, with a hyperlink<http://en.wikipedia.org/wiki/Hyperlink>. 

Sincerely, 

The whatever.com team 


Ph: 000 000 000
mail: whatever st 

...as opposed to:

        Whatever Inc.


            Thanks for your enquiry. As this is the 1st time you have contacted us, we would like to clarify a few things:

                Please confirm this is your email by replying.

                Then perform this step.


            Please solve this . Then, in any order, could you please:

                a point.

                another point, with a hyperlink.


            Sincerely,


            The whatever.com team

        Ph: 000 000 000
        mail: whatever st

Difference between DTO, VO, POJO, JavaBeans?

Basically,

DTO: "Data transfer objects " can travel between seperate layers in software architecture.

VO: "Value objects " hold a object such as Integer,Money etc.

POJO: Plain Old Java Object which is not a special object.

Java Beans: requires a Java Class to be serializable, have a no-arg constructor and a getter and setter for each field

PDF Editing in PHP?

If you are taking a 'fill in the blank' approach, you can precisely position text anywhere you want on the page. So it's relatively easy (if not a bit tedious) to add the missing text to the document. For example with Zend Framework:

<?php
require_once 'Zend/Pdf.php';

$pdf = Zend_Pdf::load('blank.pdf');
$page = $pdf->pages[0];
$font = Zend_Pdf_Font::fontWithName(Zend_Pdf_Font::FONT_HELVETICA);
$page->setFont($font, 12);
$page->drawText('Hello world!', 72, 720);
$pdf->save('zend.pdf');

If you're trying to replace inline content, such as a "[placeholder string]," it gets much more complicated. While it's technically possible to do, you're likely to mess up the layout of the page.

A PDF document is comprised of a set of primitive drawing operations: line here, image here, text chunk there, etc. It does not contain any information about the layout intent of those primitives.

fetch from origin with deleted remote branches?

If git fetch -p origin does not work for some reason (like because the origin repo no longer exists or you are unable to reach it), another solution is to remove the information which is stored locally on that branch by doing from the root of the repo:

rm .git/refs/remotes/origin/DELETED_BRANCH

or if it is stored in the file .git/packed-refs by deleting the corresponding line which is like

7a9930974b02a3b31cb2ebd17df6667514962685 refs/remotes/origin/DELETED_BRANCH

Angular 2 Unit Tests: Cannot find name 'describe'

I hope you've installed -

npm install --save-dev @types/jasmine

Then put following import at the top of the hero.spec.ts file -

import 'jasmine';

It should solve the problem.

How can I install Python's pip3 on my Mac?

Similar to Oksana but add python3

$ brew rm python 
$ brew rm python3 
$ rm -rf /usr/local/opt/python
$ rm -rf /usr/local/opt/python3
$ brew prune 
$ brew install python3
$ brew postinstall python3

Seem now work for pip3 under mac os x 10.13.3 Xcode 9.2

Removing All Items From A ComboBox?

You can use the ControlFormat method:

ComboBox1.ControlFormat.RemoveAllItems

How to add property to a class dynamically?

Not sure if I completely understand the question, but you can modify instance properties at runtime with the built-in __dict__ of your class:

class C(object):
    def __init__(self, ks, vs):
        self.__dict__ = dict(zip(ks, vs))


if __name__ == "__main__":
    ks = ['ab', 'cd']
    vs = [12, 34]
    c = C(ks, vs)
    print(c.ab) # 12

How to do error logging in CodeIgniter (PHP)

More oin regards to question part 4 How do you e-mail that error to an email address? The error_log function has email destination too. http://php.net/manual/en/function.error-log.php

Agha, here I found an example that shows a usage. Send errors message via email using error_log()

error_log($this->_errorMsg, 1, ADMIN_MAIL, "Content-Type: text/html; charset=utf8\r\nFrom: ".MAIL_ERR_FROM."\r\nTo: ".ADMIN_MAIL);

How to add an existing folder with files to SVN?

In Windows 7 I did this:

  1. Have you installed SVN and Tortoise SVN? If not, Google them and do so now.
  2. Go to your SVN folder where you may have other repos (short for repository) (or if you're creating one from scratch, choose a location C drive, D drive, etc or network path).
  3. Create a new folder to store your new repository. Call it the same name as your project title
  4. Right click the folder and choose Tortoise SVN -> Create Repository here
  5. Say yes to Create Folder Structure
  6. Click OK. You should see a new icon looking like a "wave" next to your new folder/repo
  7. Right Click the new repo and choose SVN Repo Browser
  8. Right click 'trunk'
  9. Choose ADD Folder... and point to your folder structure of your project in development.
  10. Click OK and SVN will ADD your folder structure in. Be patient! It looks like SVN has crashed/frozen. Don't worry. It's doing its work.

Done!

How to hash a password

  1. Create a salt,
  2. Create a hash password with salt
  3. Save both hash and salt
  4. decrypt with password and salt... so developers cant decrypt password
public class CryptographyProcessor
{
    public string CreateSalt(int size)
    {
        //Generate a cryptographic random number.
          RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
         byte[] buff = new byte[size];
         rng.GetBytes(buff);
         return Convert.ToBase64String(buff);
    }


      public string GenerateHash(string input, string salt)
      { 
         byte[] bytes = Encoding.UTF8.GetBytes(input + salt);
         SHA256Managed sHA256ManagedString = new SHA256Managed();
         byte[] hash = sHA256ManagedString.ComputeHash(bytes);
         return Convert.ToBase64String(hash);
      }

      public bool AreEqual(string plainTextInput, string hashedInput, string salt)
      {
           string newHashedPin = GenerateHash(plainTextInput, salt);
           return newHashedPin.Equals(hashedInput); 
      }
 }

How to open an external file from HTML

<a href="file://server/directory/file.xlsx" target="_blank"> if I remember correctly.

How to redirect docker container logs to a single file?

Assuming that you have multiple containers and you want to aggregate the logs into a single file, you need to use some log aggregator like fluentd. fluentd is supported as logging driver for docker containers.

So in docker-compose, you need to define the logging driver

  service1:
    image: webapp:0.0.1
    logging:
      driver: "fluentd"
      options:
        tag: service1 

  service2:
        image: myapp:0.0.1
        logging:
          driver: "fluentd"
          options:
            tag: service2

The second step would be update the fluentd conf to cater the logs for both service 1 and service 2

 <match service1>
   @type copy
   <store>
    @type file
    path /fluentd/log/service/service.*.log
    time_slice_format %Y%m%d
    time_slice_wait 10m
    time_format %Y%m%dT%H%M%S%z
  </store>
 </match> 
 <match service2>
    @type copy
   <store>
    @type file
    path /fluentd/log/service/service.*.log
    time_slice_format %Y%m%d
    time_slice_wait 10m
    time_format %Y%m%dT%H%M%S%
  </store>
 </match> 

In this config, we are asking logs to be written to a single file to this path
/fluentd/log/service/service.*.log

and the third step would be to run the customized fluentd which will start writing the logs to file.

Here is the link for step by step instructions

Bit Long, but correct way since you get more control over log files path etc and it works well in Docker Swarm too .

How to toggle font awesome icon on click?

You can change the code by using class definition for the i element:

<a href="javascript:void"><i class="fa fa-plus-circle"></i>Category 1</a>

Then you can switch the classes rapresenting the plus/minus state using toggleClass with multiple classes:

$('#category-tabs li a').click(function(){
    $(this).next('ul').slideToggle('500');
    $(this).find('i').toggleClass('fa-plus-circle fa-minus-circle');
});

Demo: http://jsfiddle.net/Zcn2u/

Using LIKE operator with stored procedure parameters

EG : COMPARE TO VILLAGE NAME

ALTER PROCEDURE POSMAST
(@COLUMN_NAME VARCHAR(50))
AS
SELECT * FROM TABLE_NAME
WHERE 
village_name LIKE + @VILLAGE_NAME + '%';

What is Android's file system?

since most of the devices use eMMC,the file system android uses is ext4,except for the firmware.refer-http://android-developers.blogspot.com/2010/12/saving-data-safely.html

Here is the filesystem on galaxy s4:

  • /system ext4

  • /data ext4

  • /cache ext4

  • /firmware vfat

  • /data/media /mnt/shell/emulated sdcardfs

The detailed output is as follows:

/dev/block/platform/msm_sdcc.1/by-name/system /system ext4 ro,seclabel,relatime, data=ordered 0 0

/dev/block/platform/msm_sdcc.1/by-name/userdata /data ext4 rw,seclabel,nosuid,no dev,noatime,discard,journal_checksum,journal_async_commit,noauto_da_alloc,data=o rdered 0 0

/dev/block/platform/msm_sdcc.1/by-name/cache /cache ext4 rw,seclabel,nosuid,node v,noatime,discard,journal_checksum,journal_async_commit,noauto_da_alloc,data=ord ered 0 0

/dev/block/platform/msm_sdcc.1/by-name/efs /efs ext4 rw,seclabel,nosuid,nodev,no atime,discard,journal_checksum,journal_async_commit,noauto_da_alloc,errors=panic ,data=ordered 0 0

/dev/block/platform/msm_sdcc.1/by-name/persdata /persdata/absolute ext4 rw,secla bel,nosuid,nodev,relatime,data=ordered 0 0

/dev/block/platform/msm_sdcc.1/by-name/apnhlos /firmware vfat ro,context=u:objec t_r:firmware:s0,relatime,uid=1000,gid=1000,fmask=0337,dmask=0227,codepage=cp437, iocharset=iso8859-1,shortname=lower,errors=remount-ro 0 0

/dev/block/platform/msm_sdcc.1/by-name/mdm /firmware-mdm vfat ro,context=u:objec t_r:firmware:s0,relatime,uid=1000,gid=1000,fmask=0337,dmask=0227,codepage=cp437, iocharset=iso8859-1,shortname=lower,errors=remount-ro 0 0

/data/media /mnt/shell/emulated sdcardfs rw,nosuid,nodev,relatime,uid=1023,gid=1 023 0 0

Powershell script to locate specific file/file name?

I use this form for just this sort of thing:

gci . hosts -r | ? {!$_.PSIsContainer}

. maps to positional parameter Path and "hosts" maps to positional parameter Filter. I highly recommend using Filter over Include if the provider supports filtering (and the filesystem provider does). It is a good bit faster than Include.

Can't draw Histogram, 'x' must be numeric

Use the dec argument to set "," as the decimal point by adding:

 ce <- read.table("file.txt", header = TRUE, dec = ",")

Compile to a stand-alone executable (.exe) in Visual Studio

If I understand you correctly, yes you can, but not under Visual Studio (from what I know). To force the compiler to generate a real, standalone executable (which means you use C# like any other language) you use the program mkbundle (shipped with Mono). This will compile your C# app into a real, no dependency executable.

There is a lot of misconceptions about this around the internet. It does not defeat the purpose of the .net framework like some people state, because how can you lose future features of the .net framework if you havent used these features to begin with? And when you ship updates to your app, it's not exactly hard work to run it through the mkbundle processor before building your installer. There is also a speed benefit involved making your app run at native speed (because now it IS native).

In C++ or Delphi you have the same system, but without the middle MSIL layer. So if you use a namespace or sourcefile (called a unit under Delphi), then it's compiled and included in your final binary. So your final binary will be larger (Read: "Normal" size for a real app). The same goes for the parts of the framework you use in .net, these are also included in your app. However, smart linking does shave a conciderable amount.

Hope it helps!

Change the "From:" address in Unix "mail"

Plus it's good to use -F option to specify Name of sender.

Something like this:

mail -s "$SUBJECT" $MAILTO -- -F $MAILFROM -f ${MAILFROM}@somedomain.com

Or just look at available options: http://www.courier-mta.org/sendmail.html

Array of an unknown length in C#

A little background information:

As said, if you want to have a dynamic collection of things, use a List<T>. Internally, a List uses an array for storage too. That array has a fixed size just like any other array. Once an array is declared as having a size, it doesn't change. When you add an item to a List, it's added to the array. Initially, the List starts out with an array that I believe has a length of 16. When you try to add the 17th item to the List, what happens is that a new array is allocated, that's (I think) twice the size of the old one, so 32 items. Then the content of the old array is copied into the new array. So while a List may appear dynamic to the outside observer, internally it has to comply to the rules as well.

And as you might have guessed, the copying and allocation of the arrays isn't free so one should aim to have as few of those as possible and to do that you can specify (in the constructor of List) an initial size of the array, which in a perfect scenario is just big enough to hold everything you want. However, this is micro-optimization and it's unlikely it will ever matter to you, but it's always nice to know what you're actually doing.

How to concatenate two strings in SQL Server 2005

Try something like

SELECT 'rupesh''s' + 'malviya'

+ (String Concatenation)

Difference between git pull and git pull --rebase

For this is important to understand the difference between Merge and Rebase.

Rebases are how changes should pass from the top of hierarchy downwards and merges are how they flow back upwards.

For details refer - http://www.derekgourlay.com/archives/428

Display all views on oracle database

SELECT * 
FROM DBA_OBJECTS  
WHERE OBJECT_TYPE = 'VIEW'

Cannot download Docker images behind a proxy

On CentOS the configuration file for Docker is at:

/etc/sysconfig/docker

Adding the below line helped me to get the Docker daemon working behind a proxy server:

HTTP_PROXY="http://<proxy_host>:<proxy_port>"
HTTPS_PROXY="http://<proxy_host>:<proxy_port>"

Init function in javascript and how it works

In simple word you can understand that whenever page load, by this second pair of brackets () function will have called default.We need not call the function.It is known as anonymous function.

i.e.

(function(a,b){
//Do your code here
})(1,2);

It same like as

var test = function(x,y) {
  // Do your code here
}
test(1,2);

Convert month name to month number in SQL Server

You can create a function and then refer to it in the select statement. The function may look similar to this:

if OBJECT_ID('fn_month_name_to_number', 'IF') is not null
drop function fn_month_name_to_number
go
create function fn_month_name_to_number (@monthname varchar(25))
returns int as
begin
declare @monthno as int;
select @monthno =
case @monthname
when 'January' then 1
when 'February' then 2
when 'March' then 3
when 'April' then 4
when 'May' then 5
when 'June' then 6
when 'July' then 7
when 'August' then 8
when 'September' then 9
when 'October' then 10
when 'November' then 11
when 'December' then 12
end
return @monthno
end

Then you can query it.

select fn_month_name_to_number ('February') as month_no

This query will return 2 as month number. You can pass values from a column as parameters to the function.

select fn_month_name_to_number (*columnname*) as month_no from *tablename*

Have a good day!

Calling a function from a string in C#

You can invoke methods of a class instance using reflection, doing a dynamic method invocation:

Suppose that you have a method called hello in a the actual instance (this):

string methodName = "hello";

//Get the method information using the method info class
 MethodInfo mi = this.GetType().GetMethod(methodName);

//Invoke the method
// (null- no parameter for the method call
// or you can pass the array of parameters...)
mi.Invoke(this, null);

Capturing image from webcam in java?

FMJ can do this, as can the supporting library it uses, LTI-CIVIL. Both are on sourceforge.

Python: import module from another directory at the same level in project hierarchy

I faced the same issues. To solve this, I used export PYTHONPATH="$PWD". However, in this case, you will need to modify imports in your Scripts dir depending on the below:

Case 1: If you are in the user_management dir, your scripts should use this style from Modules import LDAPManager to import module.

Case 2: If you are out of the user_management 1 level like main, your scripts should use this style from user_management.Modules import LDAPManager to import modules.

Check if a row exists, otherwise insert

This is something I just recently had to do:

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[cjso_UpdateCustomerLogin]
    (
      @CustomerID AS INT,
      @UserName AS VARCHAR(25),
      @Password AS BINARY(16)
    )
AS 
    BEGIN
        IF ISNULL((SELECT CustomerID FROM tblOnline_CustomerAccount WHERE CustomerID = @CustomerID), 0) = 0
        BEGIN
            INSERT INTO [tblOnline_CustomerAccount] (
                [CustomerID],
                [UserName],
                [Password],
                [LastLogin]
            ) VALUES ( 
                /* CustomerID - int */ @CustomerID,
                /* UserName - varchar(25) */ @UserName,
                /* Password - binary(16) */ @Password,
                /* LastLogin - datetime */ NULL ) 
        END
        ELSE
        BEGIN
            UPDATE  [tblOnline_CustomerAccount]
            SET     UserName = @UserName,
                    Password = @Password
            WHERE   CustomerID = @CustomerID    
        END

    END

get launchable activity name of package from adb

Launch your app and keep it in foreground.

Run the below command:

adb shell dumpsys window windows | find "mcurrentfocus"

NodeJS accessing file with relative path

Simple! The folder named .. is the parent folder, so you can make the path to the file you need as such

var foobar = require('../config/dev/foobar.json');

If you needed to go up two levels, you would write ../../ etc

Some more details about this in this SO answer and it's comments

Draw horizontal rule in React Native

You can use native element divider.

Install it with:

npm install --save react-native-elements
# or with yarn
yarn add react-native-elements

import { Divider } from 'react-native-elements'

Then go with:

<Divider style={{ backgroundColor: 'blue' }} />

Source

right align an image using CSS HTML

<img style="float: right;" alt="" src="http://example.com/image.png" />
<div style="clear: right">
   ...text...
</div>    

jsFiddle.

Specifying an Index (Non-Unique Key) Using JPA

A unique hand-picked collection of Index annotations

= Specifications =

= ORM Frameworks =

= ORM for Android =

= Other (difficult to categorize) =

  • Realm - Alternative DB for iOS / Android: Annotation io.realm.annotations.Index;
  • Empire-db - a lightweight yet powerful relational DB abstraction layer based on JDBC. It has no schema definition through annotations;
  • Kotlin NoSQL (GitHub) - a reactive and type-safe DSL for working with NoSQL databases (PoC): ???
  • Slick - Reactive Functional Relational Mapping for Scala. It has no schema definition through annotations.

Just go for one of them.

Rails 4: List of available datatypes

You can access this list everytime you want (even if you don't have Internet access) through:

rails generate model -h

Angular 2.0 router not working on reloading the browser

Add imports:

import { HashLocationStrategy, LocationStrategy } from '@angular/common';

And in NgModule provider, add:

providers: [{provide: LocationStrategy, useClass: HashLocationStrategy}]

In main index.html File of the App change the base href to ./index.html from /

The App when deployed in any server will give a real url for the page which can be accessed from any external application.

New line in JavaScript alert box

In JAVA app, if message is read from "properties" file.

Due to double compilation java-html,

you'll need double escape.

jsp.msg.1=First Line \\nSecond Line

will result in

First Line
Second Line

How to show "Done" button on iPhone number pad

I modified Bryan's solution to be a little more robust, so that it would play nicely with other types of keyboards that could appear in the same view. It's described here:

Create a DONE button on the iOS numpad UIKeyboard

I'd try to explain it here, but most of it is code to look at that wouldn't easily fit here

how do I change text in a label with swift?

swift solution

yourlabel.text = yourvariable

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

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

How to show first commit by 'git log'?

Short answer

git rev-list --max-parents=0 HEAD

(from tiho's comment. As Chris Johnsen notices, --max-parents was introduced after this answer was posted.)

Explanation

Technically, there may be more than one root commit. This happens when multiple previously independent histories are merged together. It is common when a project is integrated via a subtree merge.

The git.git repository has six root commits in its history graph (one each for Linus’s initial commit, gitk, some initially separate tools, git-gui, gitweb, and git-p4). In this case, we know that e83c516 is the one we are probably interested in. It is both the earliest commit and a root commit.

It is not so simple in the general case.

Imagine that libfoo has been in development for a while and keeps its history in a Git repository (libfoo.git). Independently, the “bar” project has also been under development (in bar.git), but not for as long libfoo (the commit with the earliest date in libfoo.git has a date that precedes the commit with the earliest date in bar.git). At some point the developers of “bar” decide to incorporate libfoo into their project by using a subtree merge. Prior to this merge it might have been trivial to determine the “first” commit in bar.git (there was probably only one root commit). After the merge, however, there are multiple root commits and the earliest root commit actually comes from the history of libfoo, not “bar”.

You can find all the root commits of the history DAG like this:

git rev-list --max-parents=0 HEAD

For the record, if --max-parents weren't available, this does also work:

git rev-list --parents HEAD | egrep "^[a-f0-9]{40}$"

If you have useful tags in place, then git name-rev might give you a quick overview of the history:

git rev-list --parents HEAD | egrep "^[a-f0-9]{40}$" | git name-rev --stdin

Bonus

Use this often? Hard to remember? Add a git alias for quick access

git config --global alias.first "rev-list --max-parents=0 HEAD"

Now you can simply do

git first

URL rewriting with PHP

PHP is not what you are looking for, check out mod_rewrite

No line-break after a hyphen

Try using the non-breaking hyphen &#8209;. I've replaced the dash with that character in your jsfiddle, shrunk the frame down as small as it can go, and the line doesn't split there any more.

Apk location in New Android Studio

I'm using Android Studio and gradle. It created the build/apk/<.apk> file only when I ran the project. Press the following to run your project: Alt+u, u

Android Studio: 0.5.3 Gradle: 0.9.+

How to import popper.js?

I ran into the same problem.

I downloaded the 'popper.min.js' file from the CDN on the bootstrap website.

See here: https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js

Easier than compiling the project.

Important: You must include popper after jquery but BEFORE bootstrap.

Remove file from SVN repository without deleting local copy

When you want to remove one xxx.java file from SVN:

  1. Go to workspace path where the file is located.
  2. Delete that file from the folder (xxx.java)
  3. Right click and commit, then a window will open.
  4. Select the file you deleted (xxx.java) from the folder, and again right click and delete.. it will remove the file from SVN.

DataAdapter.Fill(Dataset)

it works for me, just change: Provider=Microsoft.Jet.OLEDB.4.0 (VS2013)

OleDbConnection connection = new OleDbConnection(
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Z:\\GENERAL\\OFMPTP_PD_SG.MDB");
DataSet DS = new DataSet();
connection.Open();

string query =
@"SELECT * from MONTHLYPROD";
OleDbDataAdapter DBAdapter = new OleDbDataAdapter();
DBAdapter.SelectCommand = new OleDbCommand(query, connection);
DBAdapter.Fill(DS);

Luis Montoya

SMTP error 554

SMTP error 554 is one of the more vague error codes, but is typically caused by the receiving server seeing something in the From or To headers that it doesn't like. This can be caused by a spam trap identifying your machine as a relay, or as a machine not trusted to send mail from your domain.

We ran into this problem recently when adding a new server to our array, and we fixed it by making sure that we had the correct reverse DNS lookup set up.

Android Studio Gradle Configuration with name 'default' not found

Yet another cause - I was trying to include a module in settings.gradle using

include ':MyModule'
project(':MyModule').projectDir = new File(settingsDir, '../../MyModule')

Only problem was, I had just imported the module from Eclipse an forgot to move the directory outside my application project, i.e. the path '../../MyModule' didn't exist.

Difference between WebStorm and PHPStorm

In my own experience, even though theoretically many JetBrains products share the same functionalities, the new features that get introduced in some apps don't get immediately introduced in the others. In particular, IntelliJ IDEA has a new version once per year, while WebStorm and PHPStorm get 2 to 3 per year I think. Keep that in mind when choosing an IDE. :)

Find and Replace string in all files recursive using grep and sed

grep -rl SOSTITUTETHIS . | xargs sed -Ei 's/(.*)SOSTITUTETHIS(.*)/\1WITHTHIS\2/g'

jQuery: Uncheck other checkbox on one checked

$('.cw2').change(function () {
    if ($('input.cw2').filter(':checked').length >= 1) {
        $('input.cw2').not(this).prop('checked', false);
    } 
});


$('td, input').prop(function (){
    $(this).css({ 'background-color': '#DFD8D1' });
    $(this).addClass('changed');
});

How can I create a Java method that accepts a variable number of arguments?

This is just an extension to above provided answers.

  1. There can be only one variable argument in the method.
  2. Variable argument (varargs) must be the last argument.

Clearly explained here and rules to follow to use Variable Argument.

how to get data from selected row from datagridview

To get the cell value, you need to read it directly from DataGridView1 using e.RowIndex and e.ColumnIndex properties.

Eg:

Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
   Dim value As Object = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value

   If IsDBNull(value) Then 
      TextBox1.Text = "" ' blank if dbnull values
   Else
      TextBox1.Text = CType(value, String)
   End If
End Sub

Compute elapsed time

First, you can always grab the current time by

var currentTime = new Date();

Then you could check out this "pretty date" example at http://www.zachleat.com/Lib/jquery/humane.js

If that doesn't work for you, just google "javascript pretty date" and you'll find dozens of example scripts.

Good luck.

SSIS Excel Import Forcing Incorrect Column Type

You can convert (ie. force) the column data to text... Try this (Note: These instructions are based on Excel 2007)...

The following steps should force Excel to treat the column as text:

Open your spreadsheet with Excel.

Select the whole column that contains your "mostly numeric data" by clicking on the column header.

Click on the Data tab on the ribbon menu.

Select Text to Columns. This will bring up the Convert Text to Columns Wizard.

-On Step 1: Click Next

-On Step 2: Click Next

-On Step 3: Select Text and click Finish

Save your Excel sheet.

Retry the import using the SQL Server 2005 Import Data Wizard.

Also, here's a link to another question which has additional responses:

Import Data Wizard Does Not Like Data Type I Choose For A Column

GitHub - error: failed to push some refs to '[email protected]:myrepo.git'

In my case. I had the error because I forgot to make a commit after create a repository on github into an existing project. So I solved:

git add .
git commit -m"commentary"

Then I was able to type:

git push -u origin master

How to change the color of progressbar in C# .NET 3.5?

The VB.Net colored progressbar which respects WXP Visual Styles answer is ...

I started with the answer from 'user1032613' on 3/17/12. Note that this is now a Module, not a class. From there I converted the code but more was needed. In particular the converted code showed a DirectCast function to convert the 'state' integer to a IntPtr type which didn't work.

Imports System.Runtime.InteropServices

Public Module ModifyProgressBarColor

    Private Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) As Long

    <DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=False)> _
    Private Function SendMessage(hWnd As IntPtr, Msg As UInteger, w As IntPtr, l As IntPtr) As IntPtr
    End Function

    <System.Runtime.CompilerServices.Extension()> _
    Public Sub SetState(pBar As ProgressBar, state As Integer)

        '-- Convert state as integer to type IntPtr
        Dim s As IntPtr
        Dim y As Integer = state
        s = IntPtr.op_Explicit(y)

        '-- Modify bar color
        SendMessage(pBar.Handle, 1040, s, IntPtr.Zero)

    End Sub

End Module

And again just call this in the using code with this line:

Call ModifyProgressBarColor.SetState(prb, 2)

BTW - I tried other colors - 0, 4, 5 - they all just displayed green.

How do I detect if Python is running as a 64-bit application?

While it may work on some platforms, be aware that platform.architecture is not always a reliable way to determine whether python is running in 32-bit or 64-bit. In particular, on some OS X multi-architecture builds, the same executable file may be capable of running in either mode, as the example below demonstrates. The quickest safe multi-platform approach is to test sys.maxsize on Python 2.6, 2.7, Python 3.x.

$ arch -i386 /usr/local/bin/python2.7
Python 2.7.9 (v2.7.9:648dcafa7e5f, Dec 10 2014, 10:10:46)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import platform, sys
>>> platform.architecture(), sys.maxsize
(('64bit', ''), 2147483647)
>>> ^D
$ arch -x86_64 /usr/local/bin/python2.7
Python 2.7.9 (v2.7.9:648dcafa7e5f, Dec 10 2014, 10:10:46)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import platform, sys
>>> platform.architecture(), sys.maxsize
(('64bit', ''), 9223372036854775807)

Enable CORS in fetch api

Browser have cross domain security at client side which verify that server allowed to fetch data from your domain. If Access-Control-Allow-Origin not available in response header, browser disallow to use response in your JavaScript code and throw exception at network level. You need to configure cors at your server side.

You can fetch request using mode: 'cors'. In this situation browser will not throw execption for cross domain, but browser will not give response in your javascript function.

So in both condition you need to configure cors in your server or you need to use custom proxy server.

C# : 'is' keyword and checking for Not

if (child is IContainer ? false : true)

Form content type for a json HTTP POST?

multipart/form-data

is used when you want to upload files to the server. Please check this article for details.

Where is web.xml in Eclipse Dynamic Web Project

For gradle / maven project you can use src/main/webapp/WEB-INF folder by default:

- main
- - java
- - resources
- - webapp
- - - META-INF
- - - - context.xml
- - - WEB-INF
- - - - web.xml

How does Trello access the user's clipboard?

I actually built a Chrome extension that does exactly this, and for all web pages. The source code is on GitHub.

I find three bugs with Trello's approach, which I know because I've faced them myself :)

The copy doesn't work in these scenarios:

  1. If you already have Ctrl pressed and then hover a link and hit C, the copy doesn't work.
  2. If your cursor is in some other text field in the page, the copy doesn't work.
  3. If your cursor is in the address bar, the copy doesn't work.

I solved #1 by always having a hidden span, rather than creating one when user hits Ctrl/Cmd.

I solved #2 by temporarily clearing the zero-length selection, saving the caret position, doing the copy and restoring the caret position.

I haven't found a fix for #3 yet :) (For information, check the open issue in my GitHub project).

Can I have H2 autocreate a schema in an in-memory database?

"By default, when an application calls DriverManager.getConnection(url, ...) and the database specified in the URL does not yet exist, a new (empty) database is created."—H2 Database.

Addendum: @Thomas Mueller shows how to Execute SQL on Connection, but I sometimes just create and populate in the code, as suggested below.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

/** @see http://stackoverflow.com/questions/5225700 */
public class H2MemTest {

    public static void main(String[] args) throws Exception {
        Connection conn = DriverManager.getConnection("jdbc:h2:mem:", "sa", "");
        Statement st = conn.createStatement();
        st.execute("create table customer(id integer, name varchar(10))");
        st.execute("insert into customer values (1, 'Thomas')");
        Statement stmt = conn.createStatement();
        ResultSet rset = stmt.executeQuery("select name from customer");
        while (rset.next()) {
            String name = rset.getString(1);
            System.out.println(name);
        }
    }
}

How to check whether Kafka Server is running?

I used the AdminClient api.

Properties properties = new Properties();
properties.put("bootstrap.servers", "localhost:9092");
properties.put("connections.max.idle.ms", 10000);
properties.put("request.timeout.ms", 5000);
try (AdminClient client = KafkaAdminClient.create(properties))
{
    ListTopicsResult topics = client.listTopics();
    Set<String> names = topics.names().get();
    if (names.isEmpty())
    {
        // case: if no topic found.
    }
    return true;
}
catch (InterruptedException | ExecutionException e)
{
    // Kafka is not available
}

What do Clustered and Non clustered index actually mean?

I realize this is a very old question, but I thought I would offer an analogy to help illustrate the fine answers above.

CLUSTERED INDEX

If you walk into a public library, you will find that the books are all arranged in a particular order (most likely the Dewey Decimal System, or DDS). This corresponds to the "clustered index" of the books. If the DDS# for the book you want was 005.7565 F736s, you would start by locating the row of bookshelves that is labeled 001-099 or something like that. (This endcap sign at the end of the stack corresponds to an "intermediate node" in the index.) Eventually you would drill down to the specific shelf labelled 005.7450 - 005.7600, then you would scan until you found the book with the specified DDS#, and at that point you have found your book.

NON-CLUSTERED INDEX

But if you didn't come into the library with the DDS# of your book memorized, then you would need a second index to assist you. In the olden days you would find at the front of the library a wonderful bureau of drawers known as the "Card Catalog". In it were thousands of 3x5 cards -- one for each book, sorted in alphabetical order (by title, perhaps). This corresponds to the "non-clustered index". These card catalogs were organized in a hierarchical structure, so that each drawer would be labeled with the range of cards it contained (Ka - Kl, for example; i.e., the "intermediate node"). Once again, you would drill in until you found your book, but in this case, once you have found it (i.e, the "leaf node"), you don't have the book itself, but just a card with an index number (the DDS#) with which you could find the actual book in the clustered index.

Of course, nothing would stop the librarian from photocopying all the cards and sorting them in a different order in a separate card catalog. (Typically there were at least two such catalogs: one sorted by author name, and one by title.) In principle, you could have as many of these "non-clustered" indexes as you want.

How to compare two tags with git?

If source code is on Github, you can use their comparing tool: https://help.github.com/articles/comparing-commits-across-time/

Disable clipboard prompt in Excel VBA on workbook close

proposed solution edit works if you replace the row

Set rDst = ThisWorkbook.Sheets("SomeSheet").Cells("YourCell").Resize(rSrc.Rows.Count, rSrc.Columns.Count)

with

Set rDst = ThisWorkbook.Sheets("SomeSheet").Range("YourRange").Resize(rSrc.Rows.Count, rSrc.Columns.Count)

How to find tags with only certain attributes - BeautifulSoup

if you want to only search with attribute name with any value

from bs4 import BeautifulSoup
import re

soup= BeautifulSoup(html.text,'lxml')
results = soup.findAll("td", {"valign" : re.compile(r".*")})

as per Steve Lorimer better to pass True instead of regex

results = soup.findAll("td", {"valign" : True})

Hibernate: get entity by id

In getUserById you shouldn't create a new object (user1) which isn't used. Just assign it to the already (but null) initialized user. Otherwise Hibernate.initialize(user); is actually Hibernate.initialize(null);

Here's the new getUserById (I haven't tested this ;)):

public User getUserById(Long user_id) {
    Session session = null;
    Object user = null;
    try {
        session = HibernateUtil.getSessionFactory().openSession();
        user = (User)session.load(User.class, user_id);
        Hibernate.initialize(user);
    } catch (Exception e) {
       e.printStackTrace();
    } finally {
        if (session != null && session.isOpen()) {
            session.close();
        }
    }
    return user;
}

How can I create a correlation matrix in R?

Have a look at qtlcharts. It allows you to create interactive correlation matrices:

library(qtlcharts)
data(iris)
iris$Species <- NULL
iplotCorr(iris, reorder=TRUE)

enter image description here

It's more impressive when you correlate more variables, like in the package's vignette: enter image description here

SQL Error: ORA-00942 table or view does not exist

You cannot directly access the table with the name 'customer'. Either it should be 'user1.customer' or create a synonym 'customer' for user2 pointing to 'user1.customer'. hope this helps..

Copy directory to another directory using ADD command

You can use COPY. You need to specify the directory explicitly. It won't be created by itself

COPY go /usr/local/go

Reference: Docker CP reference

How to store Configuration file and read it using React

In case you have a .properties file or a .ini file

Actually in case if you have any file that has key value pairs like this:

someKey=someValue
someOtherKey=someOtherValue

You can import that into webpack by a npm module called properties-reader

I found this really helpful since I'm integrating react with Java Spring framework where there is already an application.properties file. This helps me to keep all config together in one place.

  1. Import that from dependencies section in package.json

"properties-reader": "0.0.16"

  1. Import this module into webpack.config.js on top

const PropertiesReader = require('properties-reader');

  1. Read the properties file

const appProperties = PropertiesReader('Path/to/your/properties.file')._properties;

  1. Import this constant as config

externals: { 'Config': JSON.stringify(appProperties) }

  1. Use it as the same way as mentioned in the accepted answer

var Config = require('Config') fetchData(Config.serverUrl + '/Enterprises/...')

How to convert an object to a byte array in C#

You are really talking about serialization, which can take many forms. Since you want small and binary, protocol buffers may be a viable option - giving version tolerance and portability as well. Unlike BinaryFormatter, the protocol buffers wire format doesn't include all the type metadata; just very terse markers to identify data.

In .NET there are a few implementations; in particular

I'd humbly argue that protobuf-net (which I wrote) allows more .NET-idiomatic usage with typical C# classes ("regular" protocol-buffers tends to demand code-generation); for example:

[ProtoContract]
public class Person {
   [ProtoMember(1)]
   public int Id {get;set;}
   [ProtoMember(2)]
   public string Name {get;set;}
}
....
Person person = new Person { Id = 123, Name = "abc" };
Serializer.Serialize(destStream, person);
...
Person anotherPerson = Serializer.Deserialize<Person>(sourceStream);

Possible to change where Android Virtual Devices are saved?

Please take note of the following : modifying android.bat in the Android tools directory, as suggested in a previous answer, may lead to problems.

If you do so, in order to legitimately have your .android directory located to a non-default location then there may be an inconsistency between the AVDs listed by Android Studio (using "Tools > Android > AVD Manager") and the AVDs listed by sdk command line tool "android avd".

I suppose that Android Studio, with its internal AVD Manager, does not use the android.bat modified path ; it relies on the ANDROID_SDK_HOME variable to locate AVDs.

My own tests have shown that Android tools correctly use the ANDROID_SDK_HOME variable.

Therefore, there is no point, as far as I know, in modifying android.bat, and using the environment variable should be preferred.

How to add and remove classes in Javascript without jQuery

When you remove RegExp from the equation you leave a less "friendly" code, but it still can be done with the (much) less elegant way of split().

function removeClass(classString, toRemove) {
    classes = classString.split(' ');
    var out = Array();
    for (var i=0; i<classes.length; i++) {
        if (classes[i].length == 0) // double spaces can create empty elements
            continue;
        if (classes[i] == toRemove) // don't include this one
            continue;
        out.push(classes[i])
    }
    return out.join(' ');
}

This method is a lot bigger than a simple replace() but at least it can be used on older browsers. And in case the browser doesn't even support the split() command it's relatively easy to add it using prototype.

"Application tried to present modally an active controller"?

I had same problem.I solve it. You can try This code:

[tabBarController setSelectedIndex:1];
[self dismissModalViewControllerAnimated:YES];

Add a scrollbar to a <textarea>

You will need to give your textarea a set height and then set overflow-y

textarea
{
resize: none;
overflow-y: scroll;
height:300px;
}

Use table name in MySQL SELECT "AS"

To declare a string literal as an output column, leave the Table off and just use Test. It doesn't need to be associated with a table among your joins, since it will be accessed only by its column alias. When using a metadata function like getColumnMeta(), the table name will be an empty string because it isn't associated with a table.

SELECT
  `field1`, 
  `field2`, 
  'Test' AS `field3` 
FROM `Test`;

Note: I'm using single quotes above. MySQL is usually configured to honor double quotes for strings, but single quotes are more widely portable among RDBMS.

If you must have a table alias name with the literal value, you need to wrap it in a subquery with the same name as the table you want to use:

SELECT
  field1,
  field2,
  field3
FROM 
  /* subquery wraps all fields to put the literal inside a table */
  (SELECT field1, field2, 'Test' AS field3 FROM Test) AS Test

Now field3 will come in the output as Test.field3.

eval command in Bash and its typical uses

The eval statement tells the shell to take eval’s arguments as command and run them through the command-line. It is useful in a situation like below:

In your script if you are defining a command into a variable and later on you want to use that command then you should use eval:

/home/user1 > a="ls | more"
/home/user1 > $a
bash: command not found: ls | more
/home/user1 > # Above command didn't work as ls tried to list file with name pipe (|) and more. But these files are not there
/home/user1 > eval $a
file.txt
mailids
remote_cmd.sh
sample.txt
tmp
/home/user1 >

Pandas split DataFrame by column value

Using groupby you could split into two dataframes like

In [1047]: df1, df2 = [x for _, x in df.groupby(df['Sales'] < 30)]

In [1048]: df1
Out[1048]:
   A  Sales
2  7     30
3  6     40
4  1     50

In [1049]: df2
Out[1049]:
   A  Sales
0  3     10
1  4     20

error: use of deleted function

gcc 4.6 supports a new feature of deleted functions, where you can write

hdealt() = delete;

to disable the default constructor.

Here the compiler has obviously seen that a default constructor can not be generated, and =delete'd it for you.

What's the difference between unit, functional, acceptance, and integration tests?

I will explain you this with a practical example and no theory stuff:

A developer writes the code. No GUI is implemented yet. The testing at this level verifies that the functions work correctly and the data types are correct. This phase of testing is called Unit testing.

When a GUI is developed, and application is assigned to a tester, he verifies business requirements with a client and executes the different scenarios. This is called functional testing. Here we are mapping the client requirements with application flows.

Integration testing: let's say our application has two modules: HR and Finance. HR module was delivered and tested previously. Now Finance is developed and is available to test. The interdependent features are also available now, so in this phase, you will test communication points between the two and will verify they are working as requested in requirements.

Regression testing is another important phase, which is done after any new development or bug fixes. Its aim is to verify previously working functions.

LINQ - Full Outer Join

Performs a in-memory streaming enumeration over both inputs and invokes the selector for each row. If there is no correlation at the current iteration, one of the selector arguments will be null.

Example:

   var result = left.FullOuterJoin(
         right, 
         x=>left.Key, 
         x=>right.Key, 
         (l,r) => new { LeftKey = l?.Key, RightKey=r?.Key });
  • Requires an IComparer for the correlation type, uses the Comparer.Default if not provided.

  • Requires that 'OrderBy' is applied to the input enumerables

    /// <summary>
    /// Performs a full outer join on two <see cref="IEnumerable{T}" />.
    /// </summary>
    /// <typeparam name="TLeft"></typeparam>
    /// <typeparam name="TValue"></typeparam>
    /// <typeparam name="TRight"></typeparam>
    /// <typeparam name="TResult"></typeparam>
    /// <param name="left"></param>
    /// <param name="right"></param>
    /// <param name="leftKeySelector"></param>
    /// <param name="rightKeySelector"></param>
    /// <param name="selector">Expression defining result type</param>
    /// <param name="keyComparer">A comparer if there is no default for the type</param>
    /// <returns></returns>
    [System.Diagnostics.DebuggerStepThrough]
    public static IEnumerable<TResult> FullOuterJoin<TLeft, TRight, TValue, TResult>(
        this IEnumerable<TLeft> left,
        IEnumerable<TRight> right,
        Func<TLeft, TValue> leftKeySelector,
        Func<TRight, TValue> rightKeySelector,
        Func<TLeft, TRight, TResult> selector,
        IComparer<TValue> keyComparer = null)
        where TLeft: class
        where TRight: class
        where TValue : IComparable
    {
    
        keyComparer = keyComparer ?? Comparer<TValue>.Default;
    
        using (var enumLeft = left.OrderBy(leftKeySelector).GetEnumerator())
        using (var enumRight = right.OrderBy(rightKeySelector).GetEnumerator())
        {
    
            var hasLeft = enumLeft.MoveNext();
            var hasRight = enumRight.MoveNext();
            while (hasLeft || hasRight)
            {
    
                var currentLeft = enumLeft.Current;
                var valueLeft = hasLeft ? leftKeySelector(currentLeft) : default(TValue);
    
                var currentRight = enumRight.Current;
                var valueRight = hasRight ? rightKeySelector(currentRight) : default(TValue);
    
                int compare =
                    !hasLeft ? 1
                    : !hasRight ? -1
                    : keyComparer.Compare(valueLeft, valueRight);
    
                switch (compare)
                {
                    case 0:
                        // The selector matches. An inner join is achieved
                        yield return selector(currentLeft, currentRight);
                        hasLeft = enumLeft.MoveNext();
                        hasRight = enumRight.MoveNext();
                        break;
                    case -1:
                        yield return selector(currentLeft, default(TRight));
                        hasLeft = enumLeft.MoveNext();
                        break;
                    case 1:
                        yield return selector(default(TLeft), currentRight);
                        hasRight = enumRight.MoveNext();
                        break;
                }
            }
    
        }
    
    }
    

jQuery Remove string from string

If you just want to remove "username1" you can use a simple replace.

name.replace("username1,", "")

or you could use split like you mentioned.

var name = "username1, username2 and username3 like this post.".split(",")[1];      
$("h1").text(name);

jsfiddle example

Check, using jQuery, if an element is 'display:none' or block on click

another shortcut i personally prefer more than .is() or .length:

if($('.myclass:visible')[0]){
   // is visible
}else {
   // is hidden
}

The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32'

Make the id parameter be a nullable int:

public ActionResult Edit(int? id, User collection)

And then add the validation:

if (Id == null) ...

Using AND/OR in if else PHP statement

There's some joking, and misleading comments, even partially incorrect information in the answers here. I'd like to try to improve on them:

First, as some have pointed out, you have a bug in your code that relates to the question:

if ($status = 'clear' AND $pRent == 0)

should be (note the == instead of = in the first part):

if ($status == 'clear' AND $pRent == 0)

which in this case is functionally equivalent to

if ($status == 'clear' && $pRent == 0)

Second, note that these operators (and or && ||) are short-circuit operators. That means if the answer can be determined with certainty from the first expression, the second one is never evaluated. Again this doesn't matter for your debugged line above, but it is extremely important when you are combining these operators with assignments, because

Third, the real difference between and or and && || is their operator precedence. Specifically the importance is that && || have higher precedence than the assignment operators (= += -= *= **= /= .= %= &= |= ^= <<= >>=) while and or have lower precendence than the assignment operators. Thus in a statement that combines the use of assignment and logical evaluation it matters which one you choose.

Modified examples from PHP's page on logical operators:

$e = false || true;

will evaluate to true and assign that value to $e, because || has higher operator precedence than =, and therefore it essentially evaluates like this:

$e = (false || true);

however

$e = false or true;

will assign false to $e (and then perform the or operation and evaluate true) because = has higher operator precedence than or, essentially evaluating like this:

($e = false) or true;

The fact that this ambiguity even exists makes a lot of programmers just always use && || and then everything works clearly as one would expect in a language like C, ie. logical operations first, then assignment.

Some languages like Perl use this kind of construct frequently in a format similar to this:

$connection = database_connect($parameters) or die("Unable to connect to DB.");

This would theoretically assign the database connection to $connection, or if that failed (and we're assuming here the function would return something that evalues to false in that case), it will end the script with an error message. Because of short-circuiting, if the database connection succeeds, the die() is never evaluated.

Some languages that allow for this construct straight out forbid assignments in conditional/logical statements (like Python) to remove the amiguity the other way round.

PHP went with allowing both, so you just have to learn about your two options once and then code how you'd like, but hopefully you'll be consistent one way or another.

Whenever in doubt, just throw in an extra set of parenthesis, which removes all ambiguity. These will always be the same:

$e = (false || true);
$e = (false or true);

Armed with all that knowledge, I prefer using and or because I feel that it makes the code more readable. I just have a rule not to combine assignments with logical evaluations. But at that point it's just a preference, and consistency matters a lot more here than which side you choose.

Proper MIME type for OTF fonts

FWIW regarding Apache 2.2 VirtualHosting and mod_mime tested on Debian Linux and OS X Leopard and Snow Leopard:

If you have a VirtualHost configuration you will want to add the types via the AddType Directive as follows at least at the bottom of the configuration as follows:

....
   AddType font/opentype .otf
   AddType font/ttf .ttf
</VirtualHost>

Tested against Chrome Unstable/Trunk and Safari WebKit Nightly which eliminates the mime octet-stream warnings for both the ttf and otf font types.

Note: .htaccess has zero effect when dealing with VirtualHosting. If you're developing for several sites you'll be using VirtualHosting development and each configuration will need these AddType additions.

finding first day of the month in python

My solution to find the first and last day of the current month:

def find_current_month_last_day(today: datetime) -> datetime:
    if today.month == 2:
        return today.replace(day=28)

    if today.month in [4, 6, 9, 11]:
        return today.replace(day=30)

    return today.replace(day=31)


def current_month_first_and_last_days() -> tuple:
    today = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
    first_date = today.replace(day=1)
    last_date = find_current_month_last_day(today)
    return first_date, last_date

What is tail call optimization?

Tail-call optimization is where you are able to avoid allocating a new stack frame for a function because the calling function will simply return the value that it gets from the called function. The most common use is tail-recursion, where a recursive function written to take advantage of tail-call optimization can use constant stack space.

Scheme is one of the few programming languages that guarantee in the spec that any implementation must provide this optimization, so here are two examples of the factorial function in Scheme:

(define (fact x)
  (if (= x 0) 1
      (* x (fact (- x 1)))))

(define (fact x)
  (define (fact-tail x accum)
    (if (= x 0) accum
        (fact-tail (- x 1) (* x accum))))
  (fact-tail x 1))

The first function is not tail recursive because when the recursive call is made, the function needs to keep track of the multiplication it needs to do with the result after the call returns. As such, the stack looks as follows:

(fact 3)
(* 3 (fact 2))
(* 3 (* 2 (fact 1)))
(* 3 (* 2 (* 1 (fact 0))))
(* 3 (* 2 (* 1 1)))
(* 3 (* 2 1))
(* 3 2)
6

In contrast, the stack trace for the tail recursive factorial looks as follows:

(fact 3)
(fact-tail 3 1)
(fact-tail 2 3)
(fact-tail 1 6)
(fact-tail 0 6)
6

As you can see, we only need to keep track of the same amount of data for every call to fact-tail because we are simply returning the value we get right through to the top. This means that even if I were to call (fact 1000000), I need only the same amount of space as (fact 3). This is not the case with the non-tail-recursive fact, and as such large values may cause a stack overflow.

Programmatically navigate using React router

So in my answer there are 3 different ways to redirect programmatically to a route. Some of the solutions has been presented already but the following ones focused only for functional components with an additional demo application.

Using the following versions:

react: 16.13.1

react-dom: 16.13.1

react-router: 5.2.0

react-router-dom: 5.2.0

typescript: 3.7.2

Configuration:

So first of all the solution is using HashRouter, configured as follows:

<HashRouter>
    // ... buttons for redirect

    <Switch>
      <Route exact path="/(|home)" children={Home} />
      <Route exact path="/usehistory" children={UseHistoryResult} />
      <Route exact path="/withrouter" children={WithRouterResult} />
      <Route exact path="/redirectpush" children={RedirectPushResult} />
      <Route children={Home} />
    </Switch>
</HashRouter>

From the documentation about <HashRouter>:

A <Router> that uses the hash portion of the URL (i.e. window.location.hash) to keep your UI in sync with the URL.

Solutions:

  1. Using <Redirect> to push using useState:

Using in a functional component (RedirectPushAction component from my repository) we can use useState to handle redirect. Tricky part is once the redirection happened we need to set the redirect state back to false. By using setTimeOut with 0 delay we are waiting until React commits Redirect to the DOM then getting back the button in order to use next time.

Please find my example below:

const [redirect, setRedirect] = useState(false);
const handleRedirect = useCallback(() => {
    let render = null;
    if (redirect) {
        render = <Redirect to="/redirectpush" push={true} />
        
        // in order wait until commiting to the DOM
        // and get back the button for clicking next time
        setTimeout(() => setRedirect(false), 0);
    }
    return render;
}, [redirect]);

return <>
    {handleRedirect()}
    <button onClick={() => setRedirect(true)}>
        Redirect push
    </button>
</>

From <Redirect> documentation:

Rendering a <Redirect> will navigate to a new location. The new location will override the current location in the history stack, like server-side redirects (HTTP 3xx) do.

  1. Using useHistory hook:

In my solution there is a component called UseHistoryAction which represents the following:

let history = useHistory();

return <button onClick={() => { history.push('/usehistory') }}>
    useHistory redirect
</button>

The useHistory hook gives us access to the history object which helps us programmatically navigate or change routes.

  1. Using withRouter, get the history from props:

Created one component called WithRouterAction, displays as below:

const WithRouterAction = (props:any) => {
    const { history } = props;

    return <button onClick={() => { history.push('/withrouter') }}>
        withRouter redirect
    </button>
}

export default withRouter(WithRouterAction);

Reading from withRouter documentation:

You can get access to the history object's properties and the closest <Route>'s match via the withRouter higher-order component. withRouter will pass updated match, location, and history props to the wrapped component whenever it renders.

Demo:

For better representation I have built a GitHub repository with these examples, please find it below:

https://github.com/norbitrial/react-router-programmatically-redirect-examples

I hope this helps!

Get Time from Getdate()

select convert(varchar(10), GETDATE(), 108)

returned 17:36:56 when I ran it a few moments ago.

SQL TRUNCATE DATABASE ? How to TRUNCATE ALL TABLES

---- Remove Constraint ----
EXEC sp_MSForEachTable "ALTER TABLE ? NOCHECK CONSTRAINT all"

---- Delete Data ----
EXEC sp_MSForEachTable "DELETE FROM ?"

---- Add Constraint ----
EXEC sp_MSForEachTable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"

---- Reset Identity value ----
EXEC sp_MSForEachTable "DBCC CHECKIDENT ( '?', RESEED, 0)"

Arduino IDE can't find ESP8266WiFi.h file

When programming the NODEMCU card with the Arduino IDE, you need to customize it and you must have selected the correct card.

Open Arduino IDE and go to files and click on the preference in the Arduino IDE.

Add the following link to the Additional Manager URLS section: "http://arduino.esp8266.com/stable/package_esp8266com_index.json" and press the OK button.

Then click Tools> Board Manager. Type "ESP8266" in the text box to search and install the ESP8266 software for Arduino IDE.

You will be successful when you try to program again by selecting the NodeMCU card after these operations. I hope I could help.

Eloquent Collection: Counting and Detect Empty

------SOLVED------

in this case you want to check two type of count for two cace

case 1:

if result contain only one record other word select single row from database using ->first()

 if(count($result)){
     
       ...record is exist true...
  }

case 2:

if result contain set of multiple row other word using ->get() or ->all()

  if($result->count()) {
    
         ...record is exist true...
  }

Using Exit button to close a winform program

In Visual Studio 2015, added this to a menu for File -> Exit and in that handler put:

this.Close();

but the IDE said 'this' was not necessary. Used the IDE suggestion with just Close(); and it worked.

CSS/HTML: Create a glowing border around an Input Field

Below is the code that Bootstrap uses. Colors are bit different but the concept is same. This is if you are using LESS to compile CSS:

// Form control focus state
//
// Generate a customized focus state and for any input with the specified color,
// which defaults to the `@input-focus-border` variable.
//
// We highly encourage you to not customize the default value, but instead use
// this to tweak colors on an as-needed basis. This aesthetic change is based on
// WebKit's default styles, but applicable to a wider range of browsers. Its
// usability and accessibility should be taken into account with any change.
//
// Example usage: change the default blue border and shadow to white for better
// contrast against a dark gray background.

.form-control-focus(@color: @input-border-focus) {
  @color-rgba: rgba(red(@color), green(@color), blue(@color), .6);
  &:focus {
    border-color: @color;
    outline: 0;
    .box-shadow(~"inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px @{color-rgba}");
  }
}

If you are not using LESS then here's the compiled version:

.form-control:focus {
    border-color: #66afe9;
    outline: 0;
    -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
    box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
}

Given an array of numbers, return array of products of all other numbers (no division)

To be complete here is the code in Scala:

val list1 = List(1, 2, 3, 4, 5)
for (elem <- list1) println(list1.filter(_ != elem) reduceLeft(_*_))

This will print out the following:

120
60
40
30
24

The program will filter out the current elem (_ != elem); and multiply the new list with reduceLeft method. I think this will be O(n) if you use scala view or Iterator for lazy eval.

Installing mcrypt extension for PHP on OSX Mountain Lion

Another possibility for those who want to keep OS X as clean as possible, is to use vagrant [1] to define a php development environment. Vagrant can use VirtualBox [2] in headless mode (~3% of CPU on my 13-inch, Mid 2009 MacBook Pro) to run a virtual machine with the webserver and php and all.

To easily create the vagrant environment you can use this great tool https://puphpet.com/

  1. http://www.vagrantup.com/
  2. https://www.virtualbox.org/

jQuery: Wait/Delay 1 second without executing code

ES6 setTimeout

setTimeout(() => {
  console.log("we waited 204586560000 ms to run this code, oh boy wowwoowee!");
}, 204586560000);

Edit: 204586560000 ms is the approximate time between the original question and this answer... assuming I calculated correctly.

Short description of the scoping rules?

Actually, a concise rule for Python Scope resolution, from Learning Python, 3rd. Ed.. (These rules are specific to variable names, not attributes. If you reference it without a period, these rules apply.)

LEGB Rule

  • Local — Names assigned in any way within a function (def or lambda), and not declared global in that function

  • Enclosing-function — Names assigned in the local scope of any and all statically enclosing functions (def or lambda), from inner to outer

  • Global (module) — Names assigned at the top-level of a module file, or by executing a global statement in a def within the file

  • Built-in (Python) — Names preassigned in the built-in names module: open, range, SyntaxError, etc

So, in the case of

code1
class Foo:
    code2
    def spam():
        code3
        for code4:
            code5
            x()

The for loop does not have its own namespace. In LEGB order, the scopes would be

  • L: Local in def spam (in code3, code4, and code5)
  • E: Any enclosing functions (if the whole example were in another def)
  • G: Were there any x declared globally in the module (in code1)?
  • B: Any builtin x in Python.

x will never be found in code2 (even in cases where you might expect it would, see Antti's answer or here).

Java Class that implements Map and keeps insertion order?

You can use LinkedHashMap to main insertion order in Map

The important points about Java LinkedHashMap class are:

  1. It contains onlyunique elements.
  2. A LinkedHashMap contains values based on the key 3.It may have one null key and multiple null values. 4.It is same as HashMap instead maintains insertion order

    public class LinkedHashMap<K,V> extends HashMap<K,V> implements Map<K,V> 
    

But if you want sort values in map using User-defined object or any primitive data type key then you should use TreeMap For more information, refer this link