Programs & Examples On #Nolock

A SQL Server table hint that can be used to prevent queries from issuing shared read locks. While often used to prevent a query from blocking other queries it also makes it susceptible to dirty reads and other potential data issues.

SQL Server NOLOCK and joins

Neither. You set the isolation level to READ UNCOMMITTED which is always better than giving individual lock hints. Or, better still, if you care about details like consistency, use snapshot isolation.

What is "with (nolock)" in SQL Server?

I use with (nolock) hint particularly in SQLServer 2000 databases with high activity. I am not certain that it is needed in SQL Server 2005 however. I recently added that hint in a SQL Server 2000 at the request of the client's DBA, because he was noticing a lot of SPID record locks.

All I can say is that using the hint has NOT hurt us and appears to have made the locking problem solve itself. The DBA at that particular client basically insisted that we use the hint.

By the way, the databases I deal with are back-ends to enterprise medical claims systems, so we are talking about millions of records and 20+ tables in many joins. I typically add a WITH (nolock) hint for each table in the join (unless it is a derived table, in which case you can't use that particular hint)

Is the NOLOCK (Sql Server hint) bad practice?

With NOLOCK hint, the transaction isolation level for the SELECT statement is READ UNCOMMITTED. This means that the query may see dirty and inconsistent data.

This is not a good idea to apply as a rule. Even if this dirty read behavior is OK for your mission critical web based application, a NOLOCK scan can cause 601 error which will terminate the query due to data movement as a result of lack of locking protection.

I suggest reading When Snapshot Isolation Helps and When It Hurts - the MSDN recommends using READ COMMITTED SNAPSHOT rather than SNAPSHOT under most circumstances.

Why is "using namespace std;" considered bad practice?

  1. You need to be able to read code written by people who have different style and best practices opinions than you.

  2. If you're only using cout, nobody gets confused. But when you have lots of namespaces flying around and you see this class and you aren't exactly sure what it does, having the namespace explicit acts as a comment of sorts. You can see at first glance, "oh, this is a filesystem operation" or "that's doing network stuff".

How can I do DNS lookups in Python, including referring to /etc/hosts?

I'm not really sure if you want to do DNS lookups yourself or if you just want a host's ip. In case you want the latter,

/!\ socket.gethostbyname is depricated, prefer socket.getaddrinfo

from man gethostbyname:

The gethostbyname*(), gethostbyaddr*(), [...] functions are obsolete. Applications should use getaddrinfo(3), getnameinfo(3),

import socket
print(socket.gethostbyname('localhost')) # result from hosts file
print(socket.gethostbyname('google.com')) # your os sends out a dns query

C++ string to double conversion

The C++ way of solving conversions (not the classical C) is illustrated with the program below. Note that the intent is to be able to use the same formatting facilities offered by iostream like precision, fill character, padding, hex, and the manipulators, etcetera.

Compile and run this program, then study it. It is simple

#include "iostream"
#include "iomanip"
#include "sstream"
using namespace std;

int main()
{
    // Converting the content of a char array or a string to a double variable
    double d;
    string S;
    S = "4.5";
    istringstream(S) >> d;    
    cout << "\nThe value of the double variable d is " << d << endl;
    istringstream("9.87654") >> d;  
    cout << "\nNow the value of the double variable d is " << d << endl;



    // Converting a double to string with formatting restrictions
    double D=3.771234567;

    ostringstream Q;
    Q.fill('#');
    Q << "<<<" << setprecision(6) << setw(20) << D << ">>>";
    S = Q.str(); // formatted converted double is now in string 

    cout << "\nThe value of the string variable S is " << S << endl;
    return 0;
}

Prof. Martinez

How to convert HTML file to word?

Try using pandoc

pandoc -f html -t docx -o output.docx input.html

If the input or output format is not specified explicitly, pandoc will attempt to guess it from the extensions of the input and output filenames.
— pandoc manual

So you can even use

pandoc -o output.docx input.html

Allow User to input HTML in ASP.NET MVC - ValidateInput or AllowHtml

If you need to allow html input for action-method parameter (opposed to "model property") there's no built-in way to do that but you can easily achieve this using a custom model binder:

public ActionResult AddBlogPost(int userId,
    [ModelBinder(typeof(AllowHtmlBinder))] string htmlBody)
{
    //...
}

The AllowHtmlBinder code:

public class AllowHtmlBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var request = controllerContext.HttpContext.Request;
        var name = bindingContext.ModelName;
        return request.Unvalidated[name]; //magic happens here
    }
}

Find the complete source code and the explanation in my blog post: https://www.jitbit.com/alexblog/273-aspnet-mvc-allowing-html-for-particular-action-parameters/

Bootstrap full responsive navbar with logo or brand name text

Just set the height and width where you are adding that logo. I tried and its working fine

How do I convert an Array to a List<object> in C#?

If array item and list item are same

List<object> list=myArray.ToList();

Order Bars in ggplot2 bar graph

I think the already provided solutions are overly verbose. A more concise way to do a frequency sorted barplot with ggplot is

ggplot(theTable, aes(x=reorder(Position, -table(Position)[Position]))) + geom_bar()

It's similar to what Alex Brown suggested, but a bit shorter and works without an anynymous function definition.

Update

I think my old solution was good at the time, but nowadays I'd rather use forcats::fct_infreq which is sorting factor levels by frequency:

require(forcats)

ggplot(theTable, aes(fct_infreq(Position))) + geom_bar()

Does 'position: absolute' conflict with Flexbox?

you have forgotten width of parent

_x000D_
_x000D_
.parent {_x000D_
   display: flex;_x000D_
   justify-content: center;_x000D_
   position: absolute;_x000D_
   width:100%_x000D_
 }
_x000D_
<div class="parent">_x000D_
  <div class="child">text</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

SQL how to increase or decrease one for a int column in one command

To answer the first:

UPDATE Orders SET Quantity = Quantity + 1 WHERE ...

To answer the second:

There are several ways to do this. Since you did not specify a database, I will assume MySQL.

  1. INSERT INTO table SET x=1, y=2 ON DUPLICATE KEY UPDATE x=x+1, y=y+2
  2. REPLACE INTO table SET x=1, y=2

They both can handle your question. However, the first syntax allows for more flexibility to update the record rather than just replace it (as the second one does).

Keep in mind that for both to exist, there has to be a UNIQUE key defined...

SQL: How to perform string does not equal

Your where clause will return all rows where tester does not match username AND where tester is not null.

If you want to include NULLs, try:

where tester <> 'username' or tester is null

If you are looking for strings that do not contain the word "username" as a substring, then like can be used:

where tester not like '%username%'

How to add a where clause in a MySQL Insert statement?

In an insert statement you wouldn't have an existing row to do a where claues on? You are inserting a new row, did you mean to do an update statment?

update users set username='JACK' and password='123' WHERE id='1';

No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here

I got the following error:

org.hibernate.HibernateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here
    at org.springframework.orm.hibernate3.SpringSessionContext.currentSession(SpringSessionContext.java:63)

I fixed this by changing my hibernate properties file

hibernate.current_session_context_class=thread

My code and configuration file as follows

session =  getHibernateTemplate().getSessionFactory().getCurrentSession();

session.beginTransaction();

session.createQuery(Qry).executeUpdate();

session.getTransaction().commit();

on properties file

hibernate.dialect=org.hibernate.dialect.MySQLDialect

hibernate.show_sql=true

hibernate.query_factory_class=org.hibernate.hql.ast.ASTQueryTranslatorFactory

hibernate.current_session_context_class=thread

on cofiguration file

<properties>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>         
<prop key="hibernate.query.factory_class">${hibernate.query_factory_class}</prop>       
<prop key="hibernate.generate_statistics">true</prop>
<prop key="hibernate.current_session_context_class">${hibernate.current_session_context_class}</prop>
</props>
</property>
</properties>

Thanks,
Ashok

HTML CSS Button Positioning

[type=submit]{
    margin-left: 121px;
    margin-top: 19px;
    width: 84px;
    height: 40px;   
    font-size:14px;
    font-weight:700;
}

How to get today's Date?

Use this code to easy get Date & Time :

package date.time;

import java.text.SimpleDateFormat;    
import java.util.Date;

public class DateTime {

    public static void main(String[] args) {
        SimpleDateFormat dnt = new SimpleDateFormat("dd/MM/yy :: HH:mm:ss");
        Date date = new Date();
        System.out.println("Today Date & Time at Now :"+dnt.format(date));  
    } 
}

Hide text using css

This is one way:

h1 {
    text-indent: -9999px;                 /* sends the text off-screen */
    background-image: url(/the_img.png);  /* shows image */
    height: 100px;                        /* be sure to set height & width */
    width: 600px;
    white-space: nowrap;            /* because only the first line is indented */
}

h1 a {
    outline: none;  /* prevents dotted line when link is active */
}

Here is another way to hide the text while avoiding the huge 9999 pixel box that the browser will create:

h1 {
    background-image: url(/the_img.png);  /* shows image */
    height: 100px;                        /* be sure to set height & width */
    width:  600px;

    /* Hide the text. */
    text-indent: 100%;
    white-space: nowrap;
    overflow: hidden;
}

Using iText to convert HTML to PDF

When I needed HTML to PDF conversion earlier this year, I tried the trial of Winnovative HTML to PDF converter (I think ExpertPDF is the same product, too). It worked great so we bought a license at that company. I don't go into it too in depth after that.

How to concatenate and minify multiple CSS and JavaScript files with Grunt.js (0.3.x)

I think may be more automatic, grunt task usemin take care to do all this jobs for you, only need some configuration:

https://stackoverflow.com/a/33481683/1897196

SQLAlchemy create_all() does not create tables

This is probably not the main reason why the create_all() method call doesn't work for people, but for me, the cobbled together instructions from various tutorials have it such that I was creating my db in a request context, meaning I have something like:

# lib/db.py
from flask import g, current_app
from flask_sqlalchemy import SQLAlchemy

def get_db():
  if 'db' not in g:
    g.db = SQLAlchemy(current_app)
  return g.db

I also have a separate cli command that also does the create_all:

# tasks/db.py
from lib.db import get_db

@current_app.cli.command('init-db')
def init_db():
  db = get_db()
  db.create_all()

I also am using a application factory.

When the cli command is run, a new app context is used, which means a new db is used. Furthermore, in this world, an import model in the init_db method does not do anything, because it may be that your model file was already loaded(and associated with a separate db).

The fix that I came around to was to make sure that the db was a single global reference:

# lib/db.py
from flask import g, current_app
from flask_sqlalchemy import SQLAlchemy

db = None
def get_db():
  global db
  if not db:
    db = SQLAlchemy(current_app)
  return db

I have not dug deep enough into flask, sqlalchemy, or flask-sqlalchemy to understand if this means that requests to the db from multiple threads are safe, but if you're reading this you're likely stuck in the baby stages of understanding these concepts too.

How to fill a datatable with List<T>

Try this

static DataTable ConvertToDatatable(List<Item> list)
{
    DataTable dt = new DataTable();

    dt.Columns.Add("Name");
    dt.Columns.Add("Price");
    dt.Columns.Add("URL");
    foreach (var item in list)
    {
        var row = dt.NewRow();

        row["Name"] = item.Name;
        row["Price"] = Convert.ToString(item.Price);
        row["URL"] = item.URL;

        dt.Rows.Add(row);
    }

    return dt;
}

Reverse ip, find domain names on ip address

From about section of Reverse IP Domain Check tool on yougetsignal:

A reverse IP domain check takes a domain name or IP address pointing to a web server and searches for other sites known to be hosted on that same web server. Data is gathered from search engine results, which are not guaranteed to be complete.

What is the equivalent of bigint in C#?

I was handling a bigint datatype to be shown in a DataGridView and made it like this

something = (int)(Int64)data_reader[0];

How to find Google's IP address?

I'm keeping the following list updated for a couple of years now:

1.0.0.0/24
1.1.1.0/24
1.2.3.0/24
8.6.48.0/21
8.8.8.0/24
8.35.192.0/21
8.35.200.0/21
8.34.216.0/21
8.34.208.0/21
23.236.48.0/20
23.251.128.0/19
63.161.156.0/24
63.166.17.128/25
64.9.224.0/19
64.18.0.0/20
64.233.160.0/19
64.233.171.0/24
65.167.144.64/28
65.170.13.0/28
65.171.1.144/28
66.102.0.0/20
66.102.14.0/24
66.249.64.0/19
66.249.92.0/24
66.249.86.0/23
70.32.128.0/19
72.14.192.0/18
74.125.0.0/16
89.207.224.0/21
104.154.0.0/15
104.132.0.0/14
107.167.160.0/19
107.178.192.0/18
108.59.80.0/20
108.170.192.0/18
108.177.0.0/17
130.211.0.0/16
142.250.0.0/15
144.188.128.0/24
146.148.0.0/17
162.216.148.0/22
162.222.176.0/21
172.253.0.0/16
173.194.0.0/16
173.255.112.0/20
192.158.28.0/22
193.142.125.0/28
199.192.112.0/22
199.223.232.0/21
206.160.135.240/24
207.126.144.0/20
208.21.209.0/24
209.85.128.0/17
216.239.32.0/19

VBA: Counting rows in a table (list object)

You can use:

Sub returnname(ByVal TableName As String)

MsgBox (Range("Table15").Rows.count)

End Sub

and call the function as below

Sub called()

returnname "Table15"

End Sub

invalid_grant trying to get oAuth token from google

There are two major reasons for invalid_grant error which you have to take care prior to the POST request for Refresh Token and Access Token.

  1. Request header must contain "content-type: application/x-www-form-urlencoded"
  2. Your request payload should be url encoded Form Data, don't send as json object.

RFC 6749 OAuth 2.0 defined invalid_grant as: The provided authorization grant (e.g., authorization code, resource owner credentials) or refresh token is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.

I found another good article, here you will find many other reasons for this error.

https://blog.timekit.io/google-oauth-invalid-grant-nightmare-and-how-to-fix-it-9f4efaf1da35

Best practice multi language website

A really simple option that works with any website where you can upload Javascript is www.multilingualizer.com

It lets you put all text for all languages onto one page and then hides the languages the user doesn't need to see. Works well.

CASE in WHERE, SQL Server

.. ELSE a.Country ...

I suppose

How to convert a pandas DataFrame subset of columns AND rows into a numpy array?

.loc accept row and column selectors simultaneously (as do .ix/.iloc FYI) This is done in a single pass as well.

In [1]: df = DataFrame(np.random.rand(4,5), columns = list('abcde'))

In [2]: df
Out[2]: 
          a         b         c         d         e
0  0.669701  0.780497  0.955690  0.451573  0.232194
1  0.952762  0.585579  0.890801  0.643251  0.556220
2  0.900713  0.790938  0.952628  0.505775  0.582365
3  0.994205  0.330560  0.286694  0.125061  0.575153

In [5]: df.loc[df['c']>0.5,['a','d']]
Out[5]: 
          a         d
0  0.669701  0.451573
1  0.952762  0.643251
2  0.900713  0.505775

And if you want the values (though this should pass directly to sklearn as is); frames support the array interface

In [6]: df.loc[df['c']>0.5,['a','d']].values
Out[6]: 
array([[ 0.66970138,  0.45157274],
       [ 0.95276167,  0.64325143],
       [ 0.90071271,  0.50577509]])

How do I get TimeSpan in minutes given two Dates?

TimeSpan span = end-start;
double totalMinutes = span.TotalMinutes;

How to prevent SIGPIPEs (or handle them properly)

What's the best practice to prevent the crash here?

Either disable sigpipes as per everybody, or catch and ignore the error.

Is there a way to check if the other side of the line is still reading?

Yes, use select().

select() doesn't seem to work here as it always says the socket is writable.

You need to select on the read bits. You can probably ignore the write bits.

When the far end closes its file handle, select will tell you that there is data ready to read. When you go and read that, you will get back 0 bytes, which is how the OS tells you that the file handle has been closed.

The only time you can't ignore the write bits is if you are sending large volumes, and there is a risk of the other end getting backlogged, which can cause your buffers to fill. If that happens, then trying to write to the file handle can cause your program/thread to block or fail. Testing select before writing will protect you from that, but it doesn't guarantee that the other end is healthy or that your data is going to arrive.

Note that you can get a sigpipe from close(), as well as when you write.

Close flushes any buffered data. If the other end has already been closed, then close will fail, and you will receive a sigpipe.

If you are using buffered TCPIP, then a successful write just means your data has been queued to send, it doesn't mean it has been sent. Until you successfully call close, you don't know that your data has been sent.

Sigpipe tells you something has gone wrong, it doesn't tell you what, or what you should do about it.

Java: Static vs inner class

An inner class cannot be static, so I am going to recast your question as "What is the difference between static and non-static nested classes?".

as u said here inner class cannot be static... i found the below code which is being given static....reason? or which is correct....

Yes, there is nothing in the semantics of a static nested type that would stop you from doing that. This snippet runs fine.

    public class MultipleInner {
        static class Inner {
        }   
    public static void main(String[] args) {
        for (int i = 0; i < 100; i++) {
            new Inner();
        }
    }
}

this is a code posted in this website...

for the question---> Can a Static Nested Class be Instantiated Multiple Times?

answer was--->

Now, of course the nested type can do its own instance control (e.g. private constructors, singleton pattern, etc) but that has nothing to do with the fact that it's a nested type. Also, if the nested type is a static enum, of course you can't instantiate it at all.

But in general, yes, a static nested type can be instantiated multiple times.

Note that technically, a static nested type is not an "inner" type.

What is InputStream & Output Stream? Why and when do we use them?

Stream: In laymen terms stream is data , most generic stream is binary representation of data.

Input Stream : If you are reading data from a file or any other source , stream used is input stream. In a simpler terms input stream acts as a channel to read data.

Output Stream : If you want to read and process data from a source (file etc) you first need to save the data , the mean to store data is output stream .

Google Map API v3 — set bounds and center

Yes, you can declare your new bounds object.

 var bounds = new google.maps.LatLngBounds();

Then for each marker, extend your bounds object:

bounds.extend(myLatLng);
map.fitBounds(bounds);

API: google.maps.LatLngBounds

Subtract days from a DateTime

I've had issues using AddDays(-1).

My solution is TimeSpan.

DateTime.Now - TimeSpan.FromDays(1);

Enter key press in C#

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == (char)Keys.Enter)
    {
        MessageBox.Show("Enter Key Pressed");
    }
}

This allows you to choose the specific Key you want, without finding the char value of the key.

C# Passing Function as Argument

There are a couple generic types in .Net (v2 and later) that make passing functions around as delegates very easy.

For functions with return types, there is Func<> and for functions without return types there is Action<>.

Both Func and Action can be declared to take from 0 to 4 parameters. For example, Func < double, int > takes one double as a parameter and returns an int. Action < double, double, double > takes three doubles as parameters and returns nothing (void).

So you can declare your Diff function to take a Func:

public double Diff(double x, Func<double, double> f) {
    double h = 0.0000001;

    return (f(x + h) - f(x)) / h;
}

And then you call it as so, simply giving it the name of the function that fits the signature of your Func or Action:

double result = Diff(myValue, Function);

You can even write the function in-line with lambda syntax:

double result = Diff(myValue, d => Math.Sqrt(d * 3.14));

How do I access my webcam in Python?

John Montgomery's, answer is great, but at least on Windows, it is missing the line

vc.release()

before

cv2.destroyWindow("preview")

Without it, the camera resource is locked, and can not be captured again before the python console is killed.

Printf width specifier to maintain precision of floating-point value

Simply use the macros from <float.h> and the variable-width conversion specifier (".*"):

float f = 3.14159265358979323846;
printf("%.*f\n", FLT_DIG, f);

Proper way to exit iPhone application?

Have you tried exit(0)?

Alternatively, [[NSThread mainThread] exit], although I have not tried that it seems like the more appropriate solution.

Removing single-quote from a string in php

Try this one. You can strip just ' and " with:

$FileName = str_replace(array('\'', '"'), '', $UserInput); 

how to set value of a input hidden field through javascript?

The first thing I will try - determine if your code with alerts is actually rendered. I see some server "if" code in what you posted, so may be condition to render javascript is not satisfied. So, on the page you working on, right-click -> view source. Try to find the js code there. Please tell us if you found the code on the page.

referenced before assignment error in python

I think you are using 'global' incorrectly. See Python reference. You should declare variable without global and then inside the function when you want to access global variable you declare it global yourvar.

#!/usr/bin/python

total

def checkTotal():
    global total
    total = 0

See this example:

#!/usr/bin/env python

total = 0

def doA():
    # not accessing global total
    total = 10

def doB():
    global total
    total = total + 1

def checkTotal():
    # global total - not required as global is required
    # only for assignment - thanks for comment Greg
    print total

def main():
    doA()
    doB()
    checkTotal()

if __name__ == '__main__':
    main()

Because doA() does not modify the global total the output is 1 not 11.

How can I compare two strings in java and define which of them is smaller than the other alphabetically?

You can use

str1.compareTo(str2);

If str1 is lexicographically less than str2, a negative number will be returned, 0 if equal or a positive number if str1 is greater.

E.g.,

"a".compareTo("b"); // returns a negative number, here -1
"a".compareTo("a"); // returns  0
"b".compareTo("a"); // returns a positive number, here 1
"b".compareTo(null); // throws java.lang.NullPointerException

CSS Classes & SubClasses

That is the backbone of CSS, the "cascade" in Cascading Style Sheets.

If you write your CSS rules in a single line it makes it easier to see the structure:

.area1 .item { color:red; }
.area2 .item { color:blue; }
.area2 .item span { font-weight:bold; }

Using multiple classes is also a good intermediate/advanced use of CSS, unfortunately there is a well known IE6 bug which limits this usage when writing cross browser code:

<div class="area1 larger"> .... </div>

.area1 { width:200px; }
.area1.larger { width:300px; }

IE6 IGNORES the first selector in a multi-class rule, so IE6 actually applies the .area1.larger rule as

/*.area1*/.larger { ... }

Meaning it will affect ALL .larger elements.

It's a very nasty and unfortunate bug (one of many) in IE6 that forces you to pretty much never use that feature of CSS if you want one clean cross-browser CSS file.

The solution then is to use CSS classname prefixes to avoid colliding wiht generic classnames:

.area1 { ... }
.area1.area1Larger { ... }

.area2.area2Larger { ... }

May as well use just one class, but that way you can keep the CSS in the logic you intended, while knowing that .area1Larger only affects .area1, etc.

Returning Arrays in Java

If you want to use the numbers method, you need an int array to store the returned value.

public static void main(String[] args){
    int[] someNumbers = numbers();
    //do whatever you want with them...
    System.out.println(Arrays.toString(someNumbers));
}

Default SQL Server Port

The default port for SQL Server Database Engine is 1433.

And as a best practice it should always be changed after the installation. 1433 is widely known which makes it vulnerable to attacks.

Explain ggplot2 warning: "Removed k rows containing missing values"

The behavior you're seeing is due to how ggplot2 deals with data that are outside the axis ranges of the plot. You can change this behavior depending on whether you use scale_y_continuous (or, equivalently, ylim) or coord_cartesian to set axis ranges, as explained below.

library(ggplot2)

# All points are visible in the plot
ggplot(mtcars, aes(mpg, hp)) + 
  geom_point()

In the code below, one point with hp = 335 is outside the y-range of the plot. Also, because we used scale_y_continuous to set the y-axis range, this point is not included in any other statistics or summary measures calculated by ggplot, such as the linear regression line.

ggplot(mtcars, aes(mpg, hp)) + 
  geom_point() +
  scale_y_continuous(limits=c(0,300)) +  # Change this to limits=c(0,335) and the warning disappars
  geom_smooth(method="lm")

Warning messages:
1: Removed 1 rows containing missing values (stat_smooth). 
2: Removed 1 rows containing missing values (geom_point).

In the code below, the point with hp = 335 is still outside the y-range of the plot, but this point is nevertheless included in any statistics or summary measures that ggplot calculates, such as the linear regression line. This is because we used coord_cartesian to set the y-axis range, and this function does not exclude points that are outside the plot ranges when it does other calculations on the data.

If you compare this and the previous plot, you can see that the linear regression line in the second plot has a slightly steeper slope, because the point with hp=335 is included when calculating the regression line, even though it's not visible in the plot.

ggplot(mtcars, aes(mpg, hp)) + 
  geom_point() +
  coord_cartesian(ylim=c(0,300)) +
  geom_smooth(method="lm")

How to get the list of all printers in computer

Try this:

foreach (string printer in System.Drawing.Printing.PrinterSettings.InstalledPrinters)
{
    MessageBox.Show(printer);
}

C++ error 'Undefined reference to Class::Function()'

Specify the Class Card for the constructor-:

void Card::Card(Card::Rank rank, Card::Suit suit) {

And also define the default constructor and destructor.

Pinging servers in Python

Here's a solution using Python's subprocess module and the ping CLI tool provided by the underlying OS. Tested on Windows and Linux. Support setting a network timeout. Doesn't need root privileges (at least on Windows and Linux).

import platform
import subprocess

def ping(host, network_timeout=3):
    """Send a ping packet to the specified host, using the system "ping" command."""
    args = [
        'ping'
    ]

    platform_os = platform.system().lower()

    if platform_os == 'windows':
        args.extend(['-n', '1'])
        args.extend(['-w', str(network_timeout * 1000)])
    elif platform_os in ('linux', 'darwin'):
        args.extend(['-c', '1'])
        args.extend(['-W', str(network_timeout)])
    else:
        raise NotImplemented('Unsupported OS: {}'.format(platform_os))

    args.append(host)

    try:
        if platform_os == 'windows':
            output = subprocess.run(args, check=True, universal_newlines=True).stdout

            if output and 'TTL' not in output:
                return False
        else:
            subprocess.run(args, check=True)

        return True
    except (subprocess.CalledProcessError, subprocess.TimeoutExpired):
        return False

How to make the Facebook Like Box responsive?

As of August 4 2015, the native facebook like box have a responsive code snippet available at Facebook Developers page.

You can generate your responsive Facebook likebox here

https://developers.facebook.com/docs/plugins/page-plugin

This is the best solution ever rather than hacking CSS.

How can I compare two ordered lists in python?

Just use the classic == operator:

>>> [0,1,2] == [0,1,2]
True
>>> [0,1,2] == [0,2,1]
False
>>> [0,1] == [0,1,2]
False

Lists are equal if elements at the same index are equal. Ordering is taken into account then.

Button Center CSS

when all else fails I just

<center> content </center>

I know its not "up to standards" any more, but if it works it works

Deployment error:Starting of Tomcat failed, the server port 8080 is already in use

I had the same problem when trying to deploy, tomcat failed to restart as Tomcat instance was running. Close the IDE and check TASk Manager - kill any javaw process running, that solved the problem for me.

How to use ImageBackground to set background image for screen in react-native

     <ImageBackground
            source={require("../assests/background_image.jpg")}
            style={styles.container}

        >
            <View
                style={{
                    flex: 1,
                    justifyContent: "center",
                    alignItems: "center"
                }}
            >
                <Button
                    onPress={() => this.props.showImagePickerComponent(this.props.navigation)}
                    title="START"
                    color="#841584"
                    accessibilityLabel="Increase Count"
                />
            </View>
        </ImageBackground>

Please use this code for set background image in react native

Why does sed not replace all occurrences?

You should add the g modifier so that sed performs a global substitution of the contents of the pattern buffer:

echo dog dog dos | sed -e 's:dog:log:g'

For a fantastic documentation on sed, check http://www.grymoire.com/Unix/Sed.html. This global flag is explained here: http://www.grymoire.com/Unix/Sed.html#uh-6

The official documentation for GNU sed is available at http://www.gnu.org/software/sed/manual/

Compare two files line by line and generate the difference in another file

You could use diff with following output formatting:

diff --old-line-format='' --unchanged-line-format='' file1 file2

--old-line-format='' , disable output for file1 if line was differ compare in file2.
--unchanged-line-format='', disable output if lines were same.

how to fix EXE4J_JAVA_HOME, No JVM could be found on your system error?

It worked for me, but the exe4j can leave a signature when you double click the .exe application

startsWith() and endsWith() functions in PHP

I would do it like this

     function startWith($haystack,$needle){
              if(substr($haystack,0, strlen($needle))===$needle)
              return true;
        }

  function endWith($haystack,$needle){
              if(substr($haystack, -strlen($needle))===$needle)
              return true;
        }

How to click on hidden element in Selenium WebDriver?

Here is the script in Python.

You cannot click on elements in selenium that are hidden. However, you can execute JavaScript to click on the hidden element for you.

element = driver.find_element_by_id(buttonID)
driver.execute_script("$(arguments[0]).click();", element)

Excel VBA Automation Error: The object invoked has disconnected from its clients

You must have used the object, released it ("disconnect"), and used it again. Release object only after you're finished with it, or when calling Form_Closing.

How to scroll table's "tbody" independent of "thead"?

The missing part is:

thead, tbody {
    display: block;
}

Demo

Are PHP Variables passed by value or by reference?

http://www.php.net/manual/en/migration5.oop.php

In PHP 5 there is a new Object Model. PHP's handling of objects has been completely rewritten, allowing for better performance and more features. In previous versions of PHP, objects were handled like primitive types (for instance integers and strings). The drawback of this method was that semantically the whole object was copied when a variable was assigned, or passed as a parameter to a method. In the new approach, objects are referenced by handle, and not by value (one can think of a handle as an object's identifier).

How to forcefully set IE's Compatibility Mode off from the server-side?

For Node/Express developers you can use middleware and set this via server.

app.use(function(req, res, next) {
  res.setHeader('X-UA-Compatible', 'IE=edge');
  next();
});

What's the difference between HEAD, working tree and index, in Git?

The difference between HEAD (current branch or last committed state on current branch), index (aka. staging area) and working tree (the state of files in checkout) is described in "The Three States" section of the "1.3 Git Basics" chapter of Pro Git book by Scott Chacon (Creative Commons licensed).

Here is the image illustrating it from this chapter:

Local Operations - working directory vs. staging area (index) vs git repository (HEAD)

In the above image "working directory" is the same as "working tree", the "staging area" is an alternate name for git "index", and HEAD points to currently checked out branch, which tip points to last commit in the "git directory (repository)"

Note that git commit -a would stage changes and commit in one step.

How to debug a referenced dll (having pdb)

Step 1: Go to Tools-->Option-->Debugging

Step 2: Uncheck Enable Just My Code

Step 3: Uncheck Require source file exactly match with original Version

Step 4: Uncheck Step over Properties and Operators

Step 5: Go to Project properties-->Debug

Step 6: Check Enable native code debugging

Bootstrap tab activation with JQuery

Applying a selector from the .nav-tabs seems to be working: See this demo.

$(document).ready(function(){
    activaTab('aaa');
});

function activaTab(tab){
    $('.nav-tabs a[href="#' + tab + '"]').tab('show');
};

I would prefer @codedme's answer, since if you know which tab you want prior to page load, you should probably change the page html and not use JS for this particular task.

I tweaked the demo for his answer, as well.

(If this is not working for you, please specify your setting - browser, environment, etc.)

C# find highest array value and index

Consider following:

    /// <summary>
    /// Returns max value
    /// </summary>
    /// <param name="arr">array to search in</param>
    /// <param name="index">index of the max value</param>
    /// <returns>max value</returns>
    public static int MaxAt(int[] arr, out int index)
    {
        index = -1;
        int max = Int32.MinValue;

        for (int i = 0; i < arr.Length; i++)
        {
            if (arr[i] > max)
            { 
                max = arr[i];
                index = i;
            }
        }

        return max;
    }

Usage:

int m, at;
m = MaxAt(new int[]{1,2,7,3,4,5,6}, out at);
Console.WriteLine("Max: {0}, found at: {1}", m, at);

Access multiple viewchildren using @viewchild

Use @ViewChildren from @angular/core to get a reference to the components

template

<div *ngFor="let v of views">
    <customcomponent #cmp></customcomponent>
</div>

component

import { ViewChildren, QueryList } from '@angular/core';

/** Get handle on cmp tags in the template */
@ViewChildren('cmp') components:QueryList<CustomComponent>;

ngAfterViewInit(){
    // print array of CustomComponent objects
    console.log(this.components.toArray());
}

l?i?v?e? ?d?e?m?o?

JavaScript code for getting the selected value from a combo box

There is an unnecessary hashtag; change the code to this:

var e = document.getElementById("ticket_category_clone").value;

What is (x & 1) and (x >>= 1)?

x & 1 is equivalent to x % 2.

x >> 1 is equivalent to x / 2

So, these things are basically the result and remainder of divide by two.

Page scroll up or down in Selenium WebDriver (Selenium 2) using java

Scrolling to the bottom of a page:

JavascriptExecutor js = ((JavascriptExecutor) driver);
js.executeScript("window.scrollTo(0, document.body.scrollHeight)");

403 Forbidden error when making an ajax Post request in Django framework

Another approach is to add X-CSRFTOKEN header with the "{{ csrf_token }}" value like in the following example:

$.ajax({
            url: "{% url 'register_lowresistancetyres' %}",
            type: "POST",
            headers: {//<==
                        "X-CSRFTOKEN": "{{ csrf_token }}"//<==
                },
            data: $(example_form).serialize(),
            success: function(data) {
                //Success code
            },
            error: function () {
                //Error code
            }
        });

How do you perform a left outer join using linq extension methods

You can create extension method like:

public static IEnumerable<TResult> LeftOuterJoin<TSource, TInner, TKey, TResult>(this IEnumerable<TSource> source, IEnumerable<TInner> other, Func<TSource, TKey> func, Func<TInner, TKey> innerkey, Func<TSource, TInner, TResult> res)
    {
        return from f in source
               join b in other on func.Invoke(f) equals innerkey.Invoke(b) into g
               from result in g.DefaultIfEmpty()
               select res.Invoke(f, result);
    }

Subtract two dates in Java

Assuming that you're constrained to using Date, you can do the following:

Date diff = new Date(d2.getTime() - d1.getTime());

Here you're computing the differences in milliseconds since the "epoch", and creating a new Date object at an offset from the epoch. Like others have said: the answers in the duplicate question are probably better alternatives (if you aren't tied down to Date).

Key Presses in Python

PyAutoGui also lets you press a button multiple times:

pyautogui.press('tab', presses=5)   # press TAB five times in a row

pyautogui.press('A', presses=1000)   # press A a thousand times in a row

How to bind list to dataGridView?

Use a BindingList and set the DataPropertyName-Property of the column.

Try the following:

...
private void BindGrid()
{
    gvFilesOnServer.AutoGenerateColumns = false;

    //create the column programatically
    DataGridViewCell cell = new DataGridViewTextBoxCell();
    DataGridViewTextBoxColumn colFileName = new DataGridViewTextBoxColumn()
    {
        CellTemplate = cell, 
        Name = "Value",
        HeaderText = "File Name",
        DataPropertyName = "Value" // Tell the column which property of FileName it should use
     };

    gvFilesOnServer.Columns.Add(colFileName);

    var filelist = GetFileListOnWebServer().ToList();
    var filenamesList = new BindingList<FileName>(filelist); // <-- BindingList

    //Bind BindingList directly to the DataGrid, no need of BindingSource
    gvFilesOnServer.DataSource = filenamesList 
}

Can Powershell Run Commands in Parallel?

If you're using latest cross platform powershell (which you should btw) https://github.com/powershell/powershell#get-powershell, you can add single & to run parallel scripts. (Use ; to run sequentially)

In my case I needed to run 2 npm scripts in parallel: npm run hotReload & npm run dev


You can also setup npm to use powershell for its scripts (by default it uses cmd on windows).

Run from project root folder: npm config set script-shell pwsh --userconfig ./.npmrc and then use single npm script command: npm run start

"start":"npm run hotReload & npm run dev"

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

Here is a simple method.

Execute following commands.

This will enable your mod_rewrite module for Apache

$sudo a2enmod rewrite

This Command will change the owner of the folder to www-data

$sudo chown -R www-data [Wordpress Folder Location]

After You executing above commands you can install any themes without FTP.

Invoking a static method using reflection

Fromthe Javadoc of Method.invoke():

If the underlying method is static, then the specified obj argument is ignored. It may be null.

What happens when you

Class klass = ...;
Method m = klass.getDeclaredMethod(methodName, paramtypes);
m.invoke(null, args)

Evenly distributing n points on a sphere

@robert king It's a really nice solution but has some sloppy bugs in it. I know it helped me a lot though, so never mind the sloppiness. :) Here is a cleaned up version....

from math import pi, asin, sin, degrees
halfpi, twopi = .5 * pi, 2 * pi
sphere_area = lambda R=1.0: 4 * pi * R ** 2

lat_dist = lambda lat, R=1.0: R*(1-sin(lat))

#A = 2*pi*R^2(1-sin(lat))
def sphere_latarea(lat, R=1.0):
    if -halfpi > lat or lat > halfpi:
        raise ValueError("lat must be between -halfpi and halfpi")
    return 2 * pi * R ** 2 * (1-sin(lat))

sphere_lonarea = lambda lon, R=1.0: \
        4 * pi * R ** 2 * lon / twopi

#A = 2*pi*R^2 |sin(lat1)-sin(lat2)| |lon1-lon2|/360
#    = (pi/180)R^2 |sin(lat1)-sin(lat2)| |lon1-lon2|
sphere_rectarea = lambda lat0, lat1, lon0, lon1, R=1.0: \
        (sphere_latarea(lat0, R)-sphere_latarea(lat1, R)) * (lon1-lon0) / twopi


def test_sphere(n_lats=10, n_lons=19, radius=540.0):
    total_area = 0.0
    for i_lons in range(n_lons):
        lon0 = twopi * float(i_lons) / n_lons
        lon1 = twopi * float(i_lons+1) / n_lons
        for i_lats in range(n_lats):
            lat0 = asin(2 * float(i_lats) / n_lats - 1)
            lat1 = asin(2 * float(i_lats+1)/n_lats - 1)
            area = sphere_rectarea(lat0, lat1, lon0, lon1, radius)
            print("{:} {:}: {:9.4f} to  {:9.4f}, {:9.4f} to  {:9.4f} => area {:10.4f}"
                    .format(i_lats, i_lons
                    , degrees(lat0), degrees(lat1)
                    , degrees(lon0), degrees(lon1)
                    , area))
            total_area += area
    print("total_area = {:10.4f} (difference of {:10.4f})"
            .format(total_area, abs(total_area) - sphere_area(radius)))

test_sphere()

Compiled vs. Interpreted Languages

A compiled language is one where the program, once compiled, is expressed in the instructions of the target machine. For example, an addition "+" operation in your source code could be translated directly to the "ADD" instruction in machine code.

An interpreted language is one where the instructions are not directly executed by the target machine, but instead read and executed by some other program (which normally is written in the language of the native machine). For example, the same "+" operation would be recognised by the interpreter at run time, which would then call its own "add(a,b)" function with the appropriate arguments, which would then execute the machine code "ADD" instruction.

You can do anything that you can do in an interpreted language in a compiled language and vice-versa - they are both Turing complete. Both however have advantages and disadvantages for implementation and use.

I'm going to completely generalise (purists forgive me!) but, roughly, here are the advantages of compiled languages:

  • Faster performance by directly using the native code of the target machine
  • Opportunity to apply quite powerful optimisations during the compile stage

And here are the advantages of interpreted languages:

  • Easier to implement (writing good compilers is very hard!!)
  • No need to run a compilation stage: can execute code directly "on the fly"
  • Can be more convenient for dynamic languages

Note that modern techniques such as bytecode compilation add some extra complexity - what happens here is that the compiler targets a "virtual machine" which is not the same as the underlying hardware. These virtual machine instructions can then be compiled again at a later stage to get native code (e.g. as done by the Java JVM JIT compiler).

How to print formatted BigDecimal values?

To set thousand separator, say 123,456.78 you have to use DecimalFormat:

     DecimalFormat df = new DecimalFormat("#,###.00");
     System.out.println(df.format(new BigDecimal(123456.75)));
     System.out.println(df.format(new BigDecimal(123456.00)));
     System.out.println(df.format(new BigDecimal(123456123456.78)));

Here is the result:

123,456.75
123,456.00
123,456,123,456.78

Although I set #,###.00 mask, it successfully formats the longer values too. Note that the comma(,) separator in result depends on your locale. It may be just space( ) for Russian locale.

Do you use source control for your database items?

We use replication and clustering to manage our databases, as well as backups. We use Serena to manage our SQL scripts and configuration implementations. Before a configuration change is made, we perform a backup as part of the change management process. This backup satisfies our rollback requirement.

I think it all depends on scale. Are you talking about enterprise applications that need offsite backups and disaster recovery? A small workgroup running an accounting application? Or everywhere in between?

/lib/ld-linux.so.2: bad ELF interpreter: No such file or directory

These are the installation i had to run in order to make it work on fedora 22 :-

glibc-2.21-7.fc22.i686

alsa-lib-1.0.29-1.fc22.i686

qt3-3.3.8b-64.fc22.i686

libusb-1:0.1.5-5.fc22.i686

Index was outside the bounds of the Array. (Microsoft.SqlServer.smo)

Upgrade your SqlServer management studio from 2008 to 2012

Or Download the service packs of SqlServer Management Studio and update probably resolve you solution

You can download the SQL Server Management studio 2012 from below link

Microsoft® SQL Server® 2012 Express http://www.microsoft.com/en-us/download/details.aspx?id=29062

Angular error: "Can't bind to 'ngModel' since it isn't a known property of 'input'"

If even after importing the formsmodule the problem persists, check that your Input does not have a "name" attribute with value equal to another input on page.

What is difference between monolithic and micro kernel?

Monolithic kernel has all kernel services along with kernel core part, thus are heavy and has negative impact on speed and performance. On the other hand micro kernel is lightweight causing increase in performance and speed.
I answered same question at wordpress site. For the difference between monolithic, microkernel and exokernel in tabular form, you can visit here

npm not working after clearing cache

try this one npm cache clean --force after that run npm cache verify

How to make Java 6, which fails SSL connection with "SSL peer shut down incorrectly", succeed like Java 7?

It seems that in the debug log for Java 6 the request is send in SSLv2 format.

main, WRITE: SSLv2 client hello message, length = 110

This is not mentioned as enabled by default in Java 7.
Change the client to use SSLv3 and above to avoid such interoperability issues.

Look for differences in JSSE providers in Java 7 and Java 6

List of Java processes

To know the list of java running on the linux machine. ps -e | grep java

How to get request URL in Spring Boot RestController

Add a parameter of type UriComponentsBuilder to your controller method. Spring will give you an instance that's preconfigured with the URI for the current request, and you can then customize it (such as by using MvcUriComponentsBuilder.relativeTo to point at a different controller using the same prefix).

How to open port in Linux

The following configs works on Cent OS 6 or earlier

As stated above first have to disable selinux.

Step 1 nano /etc/sysconfig/selinux

Make sure the file has this configurations

SELINUX=disabled

SELINUXTYPE=targeted

Then restart the system

Step 2

iptables -A INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT

Step 3

sudo service iptables save

For Cent OS 7

step 1

firewall-cmd --zone=public --permanent --add-port=8080/tcp

Step 2

firewall-cmd --reload

HTML5 video won't play in Chrome only

Have you tried by setting the MIME type of your .m4v to "video/m4v" or "video/x-m4v" ?

Browsers might use the canPlayType method internally to check if a <source> is candidate to playback.

In Chrome, I have these results:

document.createElement("video").canPlayType("video/mp4"); // "maybe"
document.createElement("video").canPlayType("video/m4v"); // ""
document.createElement("video").canPlayType("video/x-m4v"); // "maybe"

Get PHP class property by string

In case anyone else wants to find a deep property of unknown depth, I came up with the below without needing to loop through all known properties of all children.

For example, to find $Foo->Bar->baz, or $Foo->baz, or $Foo->Bar->Baz->dave, where $path is a string like 'foo/bar/baz'.

public function callModule($pathString, $delimiter = '/'){

    //split the string into an array
    $pathArray = explode($delimiter, $pathString);

    //get the first and last of the array
    $module = array_shift($pathArray);
    $property = array_pop($pathArray);

    //if the array is now empty, we can access simply without a loop
    if(count($pathArray) == 0){
        return $this->{$module}->{$property};
    }

    //we need to go deeper
    //$tmp = $this->Foo
    $tmp = $this->{$module};

    foreach($pathArray as $deeper){
        //re-assign $tmp to be the next level of the object
        // $tmp = $Foo->Bar --- then $tmp = $Bar->baz
        $tmp = $tmp->{$deeper};
    }

    //now we are at the level we need to be and can access the property
    return $tmp->{$property};

}

And then call with something like:

$propertyString = getXMLAttribute('string'); // '@Foo/Bar/baz'
$propertyString = substr($propertyString, 1);
$moduleCaller = new ModuleCaller();
echo $moduleCaller->callModule($propertyString);

When should I use a trailing slash in my URL?

That's not really a question of aesthetics, but indeed a technical difference. The directory thinking of it is totally correct and pretty much explaining everything. Let's work it out:

You are back in the stone age now or only serve static pages

You have a fixed directory structure on your web server and only static files like images, html and so on — no server side scripts or whatsoever.

A browser requests /index.htm, it exists and is delivered to the client. Later you have lots of - let's say - DVD movies reviewed and a html page for each of them in the /dvd/ directory. Now someone requests /dvd/adams_apples.htm and it is delivered because it is there.

At some day, someone just requests /dvd/ - which is a directory and the server is trying to figure out what to deliver. Besides access restrictions and so on there are two possibilities: Show the user the directory content (I bet you already have seen this somewhere) or show a default file (in Apache it is: DirectoryIndex: sets the file that Apache will serve if a directory is requested.)

So far so good, this is the expected case. It already shows the difference in handling, so let's get into it:

At 5:34am you made a mistake uploading your files

(Which is by the way completely understandable.) So, you did something entirely wrong and instead of uploading /dvd/the_big_lebowski.htm you uploaded that file as dvd (with no extension) to /.

Someone bookmarked your /dvd/ directory listing (of course you didn't want to create and always update that nifty index.htm) and is visiting your web-site. Directory content is delivered - all fine.

Someone heard of your list and is typing /dvd. And now it is screwed. Instead of your DVD directory listing the server finds a file with that name and is delivering your Big Lebowski file.

So, you delete that file and tell the guy to reload the page. Your server looks for the /dvd file, but it is gone. Most servers will then notice that there is a directory with that name and tell the client that what it was looking for is indeed somewhere else. The response will most likely be be:

Status Code:301 Moved Permanently with Location: http://[...]/dvd/

So, totally ignoring what you think about directories or files, the server only can handle such stuff and - unless told differently - decides for you about the meaning of "slash or not".

Finally after receiving this response, the client loads /dvd/ and everything is fine.

Is it fine? No.

"Just fine" is not good enough for you

You have some dynamic page where everything is passed to /index.php and gets processed. Everything worked quite good until now, but that entire thing starts to feel slower and you investigate.

Soon, you'll notice that /dvd/list is doing exactly the same: Redirecting to /dvd/list/ which is then internally translated into index.php?controller=dvd&action=list. One additional request - but even worse! customer/login redirects to customer/login/ which in turn redirects to the HTTPS URL of customer/login/. You end up having tons of unnecessary HTTP redirects (= additional requests) that make the user experience slower.

Most likely you have a default directory index here, too: index.php?controller=dvd with no action simply internally loads index.php?controller=dvd&action=list.

Summary:

  • If it ends with / it can never be a file. No server guessing.

  • Slash or no slash are entirely different meanings. There is a technical/resource difference between "slash or no slash", and you should be aware of it and use it accordingly. Just because the server most likely loads /dvd/index.htm - or loads the correct script stuff - when you say /dvd: It does it, but not because you made the right request. Which would have been /dvd/.

  • Omitting the slash even if you indeed mean the slashed version gives you an additional HTTP request penalty. Which is always bad (think of mobile latency) and has more weight than a "pretty URL" - especially since crawlers are not as dumb as SEOs believe or want you to believe ;)

Virtual network interface in Mac OS X

The loopback adapter is always up.

ifconfig lo0 alias 172.16.123.1 will add an alias IP 172.16.123.1 to the loopback adapter

ifconfig lo0 -alias 172.16.123.1 will remove it

Can't connect to Postgresql on port 5432

You have to edit postgresql.conf file and change line with 'listen_addresses'.

This file you can find in the /etc/postgresql/9.3/main directory.

Default Ubuntu config have allowed only localhost (or 127.0.0.1) interface, which is sufficient for using, when every PostgreSQL client work on the same computer, as PostgreSQL server. If you want connect PostgreSQL server from other computers, you have change this config line in this way:

listen_addresses = '*'

Then you have edit pg_hba.conf file, too. In this file you have set, from which computers you can connect to this server and what method of authentication you can use. Usually you will need similar line:

host    all         all         192.168.1.0/24        md5

Please, read comments in this file...

EDIT:

After the editing postgresql.conf and pg_hba.conf you have to restart postgresql server.

EDIT2: Highlited configuration files.

Terminating a Java Program

What does return; mean?

return; really means it returns nothing void. That's it.

why return; or other codes can write below the statement of System.exit(0);

It is allowed since compiler doesn't know calling System.exit(0) will terminate the JVM. The compiler will just give a warning - unnecessary return statement

IIS AppPoolIdentity and file system write access permissions

Each application pool in IIs creates its own secure user folder with FULL read/write permission by default under c:\users. Open up your Users folder and see what application pool folders are there, right click, and check their rights for the application pool virtual account assigned. You should see your application pool account added already with read/write access assigned to its root and subfolders.

So that type of file storage access is automatically done and you should be able to write whatever you like there in the app pools user account folders without changing anything. That's why virtual user accounts for each application pool were created.

How to change time in DateTime?

If you already have the time stored in another DateTime object you can use the Add method.

DateTime dateToUse = DateTime.Now();
DateTime timeToUse = new DateTime(2012, 2, 4, 10, 15, 30); //10:15:30 AM

DateTime dateWithRightTime = dateToUse.Date.Add(timeToUse.TimeOfDay);

The TimeOfDay property is a TimeSpan object and can be passed to the Add method. And since we use the Date property of the dateToUse variable we get just the date and add the time span.

Rounding a variable to two decimal places C#

You should use a form of Math.Round. Be aware that Math.Round defaults to banker's rounding (rounding to the nearest even number) unless you specify a MidpointRounding value. If you don't want to use banker's rounding, you should use Math.Round(decimal d, int decimals, MidpointRounding mode), like so:

Math.Round(pay, 2, MidpointRounding.AwayFromZero); // .005 rounds up to 0.01
Math.Round(pay, 2, MidpointRounding.ToEven);       // .005 rounds to nearest even (0.00) 
Math.Round(pay, 2);    // Defaults to MidpointRounding.ToEven

(Why does .NET use banker's rounding?)

Converting unix timestamp string to readable date

Another way that this can be done using gmtime and format function;

from time import gmtime
print('{}-{}-{} {}:{}:{}'.format(*gmtime(1538654264.703337)))

Output: 2018-10-4 11:57:44

Removing address bar from browser (to view on Android)

this works on android (at least on stock gingerbread browser):

<body onload="document.body.style.height=(2*window.innerHeight-window.outerHeight)+'px';"></body>

further if you want to disable scrolling you can use

setInterval(function(){window.scrollTo(1,0)},50);

How to solve munmap_chunk(): invalid pointer error in C++

The hint is, the output file is created even if you get this error. The automatic deconstruction of vector starts after your code executed. Elements in the vector are deconstructed as well. This is most probably where the error occurs. The way you access the vector is through vector::operator[] with an index read from stream. Try vector::at() instead of vector::operator[]. This won't solve your problem, but will show which assignment to the vector causes error.

How to disable scrolling temporarily?

Store scroll length in a global variable and restore it when needed!

var sctollTop_length = 0;

function scroll_pause(){
  sctollTop_length = $(window).scrollTop();
  $("body").css("overflow", "hidden");
}

function scroll_resume(){
  $("body").css("overflow", "auto");
  $(window).scrollTop(sctollTop_length);
}

What does this symbol mean in JavaScript?

See the documentation on MDN about expressions and operators and statements.

Basic keywords and general expressions

this keyword:

var x = function() vs. function x() — Function declaration syntax

(function(){})() — IIFE (Immediately Invoked Function Expression)

someFunction()() — Functions which return other functions

=> — Equal sign, greater than: arrow function expression syntax

|> — Pipe, greater than: Pipeline operator

function*, yield, yield* — Star after function or yield: generator functions

[], Array() — Square brackets: array notation

If the square brackets appear on the left side of an assignment ([a] = ...), or inside a function's parameters, it's a destructuring assignment.

{key: value} — Curly brackets: object literal syntax (not to be confused with blocks)

If the curly brackets appear on the left side of an assignment ({ a } = ...) or inside a function's parameters, it's a destructuring assignment.

`${}` — Backticks, dollar sign with curly brackets: template literals

// — Slashes: regular expression literals

$ — Dollar sign in regex replace patterns: $$, $&, $`, $', $n

() — Parentheses: grouping operator


Property-related expressions

obj.prop, obj[prop], obj["prop"] — Square brackets or dot: property accessors

?., ?.[], ?.() — Question mark, dot: optional chaining operator

:: — Double colon: bind operator

new operator

...iter — Three dots: spread syntax; rest parameters


Increment and decrement

++, -- — Double plus or minus: pre- / post-increment / -decrement operators


Unary and binary (arithmetic, logical, bitwise) operators

delete operator

void operator

+, - — Plus and minus: addition or concatenation, and subtraction operators; unary sign operators

|, &, ^, ~ — Single pipe, ampersand, circumflex, tilde: bitwise OR, AND, XOR, & NOT operators

% — Percent sign: remainder operator

&&, ||, ! — Double ampersand, double pipe, exclamation point: logical operators

?? — Double question mark: nullish-coalescing operator

** — Double star: power operator (exponentiation)


Equality operators

==, === — Equal signs: equality operators

!=, !== — Exclamation point and equal signs: inequality operators


Bit shift operators

<<, >>, >>> — Two or three angle brackets: bit shift operators


Conditional operator

?:… — Question mark and colon: conditional (ternary) operator


Assignment operators

= — Equal sign: assignment operator

%= — Percent equals: remainder assignment

+= — Plus equals: addition assignment operator

&&=, ||=, ??= — Double ampersand, pipe, or question mark, followed by equal sign: logical assignments

Destructuring


Comma operator

, — Comma operator


Control flow

{} — Curly brackets: blocks (not to be confused with object literal syntax)

Declarations

var, let, const — Declaring variables


Label

label: — Colon: labels


# — Hash (number sign): Private methods or private fields

How do I get the base URL with PHP?

Try the following code :

$config['base_url'] = ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == "on") ? "https" : "http");
$config['base_url'] .= "://".$_SERVER['HTTP_HOST'];
$config['base_url'] .= str_replace(basename($_SERVER['SCRIPT_NAME']),"",$_SERVER['SCRIPT_NAME']);
echo $config['base_url'];

Using Composer's Autoload

In my opinion, Sergiy's answer should be the selected answer for the given question. I'm sharing my understanding.

I was looking to autoload my package files using composer which I have under the dir structure given below.

<web-root>
    |--------src/
    |           |--------App/
    |           |
    |           |--------Test/
    |
    |---------library/
    |
    |---------vendor/
    |           |
    |           |---------composer/
    |           |           |---------autoload_psr4.php
    |           |           
    |           |----------autoload.php
    |
    |-----------composer.json
    |

I'm using psr-4 autoloading specification.

Had to add below lines to the project's composer.json. I intend to place my class files inside src/App , src/Test and library directory.

"autoload": {
        "psr-4": {
            "OrgName\\AppType\\AppName\\": ["src/App", "src/Test", "library/"]
        }
    } 

This is pretty much self explaining. OrgName\AppType\AppName is my intended namespace prefix. e.g for class User in src/App/Controller/Provider/User.php -

namespace OrgName\AppType\AppName\Controller\Provider; // namespace declaration

use OrgName\AppType\AppName\Controller\Provider\User; // when using the class

Also notice "src/App", "src/Test" .. are from your web-root that is where your composer.json is. Nothing to do with the vendor dir. take a look at vendor/autoload.php

Now if composer is installed properly all that is required is #composer update

After composer update my classes loaded successfully. What I observed is that composer is adding a line in vendor/composer/autoload_psr4.php

$vendorDir = dirname(dirname(__FILE__));
$baseDir = dirname($vendorDir);

return array(
    'Monolog\\' => array($vendorDir . '/monolog/monolog/src/Monolog'),
    'OrgName\\AppType\\AppName\\' => array($baseDir . '/src/App', $baseDir . '/src/Test', $baseDir . '/library'),
);

This is how composer maps. For psr-0 mapping is in vendor/composer/autoload_classmap.php

How do I view the SSIS packages in SQL Server Management Studio?

If you deployed the package to the "Integration Services Catalog" on SSMS you can retrieve the package using Visual studio.

enter image description here

How to fix 'android.os.NetworkOnMainThreadException'?

I solved this problem using a new Thread.

Thread thread = new Thread(new Runnable() {

    @Override
    public void run() {
        try  {
            //Your code goes here
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
});

thread.start(); 

The type arguments for method cannot be inferred from the usage

Now my aim was to have one pair with an base type and a type definition (Requirement A). For the type definition I want to use inheritance (Requirement B). The use should be possible, without explicite knowledge over the base type (Requirement C).

After I know now that the gernic constraints are not used for solving the generic return type, I experimented a little bit:

Ok let's introducte Get2:

class ServiceGate
{
    public IAccess<C, T> Get1<C, T>(C control) where C : ISignatur<T>
    {
        throw new NotImplementedException();
    }

    public IAccess<ISignatur<T>, T> Get2<T>(ISignatur<T> control)
    {
        throw new NotImplementedException();
    }
}

class Test
{
    static void Main()
    {
        ServiceGate service = new ServiceGate();
        //var bla1 = service.Get1(new Signatur()); // CS0411
        var bla = service.Get2(new Signatur()); // Works
    }
}

Fine, but this solution reaches not requriement B.

Next try:

class ServiceGate
{
    public IAccess<C, T> Get3<C, T>(C control, ISignatur<T> iControl) where C : ISignatur<T>
    {
        throw new NotImplementedException();
    }

}

class Test
{
    static void Main()
    {
        ServiceGate service = new ServiceGate();
        //var bla1 = service.Get1(new Signatur()); // CS0411
        var bla = service.Get2(new Signatur()); // Works
        var c = new Signatur();
        var bla3 = service.Get3(c, c); // Works!! 
    }
}

Nice! Now the compiler can infer the generic return types. But i don't like it. Other try:

class IC<A, B>
{
    public IC(A a, B b)
    {
        Value1 = a;
        Value2 = b;
    }

    public A Value1 { get; set; }

    public B Value2 { get; set; }
}

class Signatur : ISignatur<bool>
{
    public string Test { get; set; }

    public IC<Signatur, ISignatur<bool>> Get()
    {
        return new IC<Signatur, ISignatur<bool>>(this, this);
    }
}

class ServiceGate
{
    public IAccess<C, T> Get4<C, T>(IC<C, ISignatur<T>> control) where C : ISignatur<T>
    {
        throw new NotImplementedException();
    }
}

class Test
{
    static void Main()
    {
        ServiceGate service = new ServiceGate();
        //var bla1 = service.Get1(new Signatur()); // CS0411
        var bla = service.Get2(new Signatur()); // Works
        var c = new Signatur();
        var bla3 = service.Get3(c, c); // Works!!
        var bla4 = service.Get4((new Signatur()).Get()); // Better...
    }
}

My final solution is to have something like ISignature<B, C>, where B ist the base type and C the definition...

Tracing XML request/responses with JAX-WS

I am posting a new answer, as I do not have enough reputation to comment on the one provided by Antonio (see: https://stackoverflow.com/a/1957777).

In case you want the SOAP message to be printed in a file (e.g. via Log4j), you may use:

OutputStream os = new ByteArrayOutputStream();
javax.xml.soap.SOAPMessage soapMsg = context.getMessage();
soapMsg.writeTo(os);
Logger LOG = Logger.getLogger(SOAPLoggingHandler.class); // Assuming SOAPLoggingHandler is the class name
LOG.info(os.toString());

Please note that under certain circumstances, the method call writeTo() may not behave as expected (see: https://community.oracle.com/thread/1123104?tstart=0 or https://www.java.net/node/691073), therefore the following code will do the trick:

javax.xml.soap.SOAPMessage soapMsg = context.getMessage();
com.sun.xml.ws.api.message.Message msg = new com.sun.xml.ws.message.saaj.SAAJMessage(soapMsg);
com.sun.xml.ws.api.message.Packet packet = new com.sun.xml.ws.api.message.Packet(msg);
Logger LOG = Logger.getLogger(SOAPLoggingHandler.class); // Assuming SOAPLoggingHandler is the class name
LOG.info(packet.toString());

scale fit mobile web content using viewport meta tag

For Android there is the addition of target-density tag.

target-densitydpi=device-dpi

So, the code would look like

<meta name="viewport" content="width=device-width, target-densitydpi=device-dpi, initial-scale=0, maximum-scale=1, user-scalable=yes" />

Please note, that I believe this addition is only for Android (but since you have answers, I felt this was a good extra) but this should work for most mobile devices.

Loading a properties file from Java package

I managed to solve this issue with this call

Properties props = PropertiesUtil.loadProperties("whatever.properties");

Extra, you have to put your whatever.properties file in /src/main/resources

Git error: "Please make sure you have the correct access rights and the repository exists"

Very common mistake was done by me. I copied using clip command xclip -sel clip < ~/.ssh/id_rsa.pub, but during pasting into github key input box, I removed last newline using backspace, which actually changed the public key.

So, always copy & paste ssh public key as it is without removing last newline.

The result of a query cannot be enumerated more than once

Try replacing this

var query = context.Search(id, searchText);

with

var query = context.Search(id, searchText).tolist();

and everything will work well.

Initializing array of structures

It's called designated initializer which is introduced in C99. It's used to initialize struct or arrays, in this example, struct.

Given

struct point { 
    int x, y;
};

the following initialization

struct point p = { .y = 2, .x = 1 };

is equivalent to the C89-style

struct point p = { 1, 2 };

How do I import a CSV file in R?

You would use the read.csv function; for example:

dat = read.csv("spam.csv", header = TRUE)

You can also reference this tutorial for more details.

Note: make sure the .csv file to read is in your working directory (using getwd()) or specify the right path to file. If you want, you can set the current directory using setwd.

Adobe Reader Command Line Reference

Call this after the print job has returned:

oShell.AppActivate "Adobe Reader"
oShell.SendKeys "%FX"

Position Relative vs Absolute?

Absolute will make your element out of your flow layout, and it will be positioned to the closest relative parent (all parents are static by default). That's how you use absolute and relative together most of the time.

You can also use relative alone, but that is very rare case.

I have made an video to explain this.

https://www.youtube.com/watch?v=nGN5CohGVTI

SQL split values to multiple rows

If the name column were a JSON array (like '["a","b","c"]'), then you could extract/unpack it with JSON_TABLE() (available since MySQL 8.0.4):

select t.id, j.name
from mytable t
join json_table(
  t.name,
  '$[*]' columns (name varchar(50) path '$')
) j;

Result:

| id  | name |
| --- | ---- |
| 1   | a    |
| 1   | b    |
| 1   | c    |
| 2   | b    |

View on DB Fiddle

If you store the values in a simple CSV format, then you would first need to convert it to JSON:

select t.id, j.name
from mytable t
join json_table(
  replace(json_array(t.name), ',', '","'),
  '$[*]' columns (name varchar(50) path '$')
) j

Result:

| id  | name |
| --- | ---- |
| 1   | a    |
| 1   | b    |
| 1   | c    |
| 2   | b    |

View on DB Fiddle

Installation of VB6 on Windows 7 / 8 / 10

I've installed and use VB6 for legacy projects many times on Windows 7.

What I have done and never came across any issues, is to install VB6, ignore the errors and then proceed to install the latest service pack, currently SP6.

Download here: http://www.microsoft.com/en-us/download/details.aspx?id=5721

Bonus: Also once you install it and realize that scrolling doesn't work, use the below: http://www.joebott.com/vb6scrollwheel.htm

Python AttributeError: 'module' object has no attribute 'Serial'

I accidentally installed 'serial' (sudo python -m pip install serial) instead of 'pySerial' (sudo python -m pip install pyserial), which lead to the same error.

If the previously mentioned solutions did not work for you, double check if you installed the correct library.

How to read the content of a file to a string in C?

I will add my own version, based on the answers here, just for reference. My code takes into consideration sizeof(char) and adds a few comments to it.

// Open the file in read mode.
FILE *file = fopen(file_name, "r");
// Check if there was an error.
if (file == NULL) {
    fprintf(stderr, "Error: Can't open file '%s'.", file_name);
    exit(EXIT_FAILURE);
}
// Get the file length
fseek(file, 0, SEEK_END);
long length = ftell(file);
fseek(file, 0, SEEK_SET);
// Create the string for the file contents.
char *buffer = malloc(sizeof(char) * (length + 1));
buffer[length] = '\0';
// Set the contents of the string.
fread(buffer, sizeof(char), length, file);
// Close the file.
fclose(file);
// Do something with the data.
// ...
// Free the allocated string space.
free(buffer);

How do I upgrade PHP in Mac OS X?

I use this: https://github.com/Homebrew/homebrew-php

The command is:

$ xcode-select --install

$ brew tap homebrew/dupes
$ brew tap homebrew/versions
$ brew tap homebrew/homebrew-php

$ brew options php56
$ brew install php56

Then config in your .bash_profile or .bashrc

# Homebrew PHP CLI
export PATH="$(brew --prefix homebrew/php/php56)/bin:$PATH"

OpenCV in Android Studio

Android Studio 3.4 + OpenCV 4.1

  1. Download the latest OpenCV zip file from here (current newest version is 4.1.0) and unzip it in your workspace or in another folder.

  2. Create new Android Studio project normally. Click File->New->Import Module, navigate to /path_to_unzipped_files/OpenCV-android-sdk/sdk/java, set Module name as opencv, click Next and uncheck all options in the screen.

  3. Enable Project file view mode (default mode is Android). In the opencv/build.gradle file change apply plugin: 'com.android.application' to apply plugin: 'com.android.library' and replace application ID "org.opencv" with

    minSdkVersion 21
    targetSdkVersion 28
    

    (according the values in app/build.gradle). Sync project with Gradle files.

  4. Add this string to the dependencies block in the app/build.gradle file

    dependencies {
        ...
        implementation project(path: ':opencv')
        ...
    }
    
  5. Select again Android file view mode. Right click on app module and goto New->Folder->JNI Folder. Select change folder location and set src/main/jniLibs/.

  6. Select again Project file view mode and copy all folders from /path_to_unzipped_files/OpenCV-android-sdk/sdk/native/libs to app/src/main/jniLibs.

  7. Again in Android file view mode right click on app module and choose Link C++ Project with Gradle. Select Build System ndk-build and path to OpenCV.mk file /path_to_unzipped_files/OpenCV-android-sdk/sdk/native/jni/OpenCV.mk.

    path_to_unzipped_files must not contain any spaces, or you will get error!

To check OpenCV initialization add Toast message in MainActivity onCreate() method:

Toast.makeText(MainActivity.this, String.valueOf(OpenCVLoader.initDebug()), Toast.LENGTH_LONG).show();

If initialization is successful you will see true in Toast message else you will see false.

Python 3: UnboundLocalError: local variable referenced before assignment

If you set the value of a variable inside the function, python understands it as creating a local variable with that name. This local variable masks the global variable.

In your case, Var1 is considered as a local variable, and it's used before being set, thus the error.

To solve this problem, you can explicitly say it's a global by putting global Var1 in you function.

Var1 = 1
Var2 = 0
def function():
    global Var1
    if Var2 == 0 and Var1 > 0:
        print("Result One")
    elif Var2 == 1 and Var1 > 0:
        print("Result Two")
    elif Var1 < 1:
        print("Result Three")
    Var1 =- 1
function()

Java RegEx meta character (.) and ordinary dot?

I wanted to match a string that ends with ".*" For this I had to use the following:

"^.*\\.\\*$"

Kinda silly if you think about it :D Heres what it means. At the start of the string there can be any character zero or more times followed by a dot "." followed by a star (*) at the end of the string.

I hope this comes in handy for someone. Thanks for the backslash thing to Fabian.

Cancel a UIView animation?

Use:

#import <QuartzCore/QuartzCore.h>

.......

[myView.layer removeAllAnimations];

Error CS2001: Source file '.cs' could not be found

I open the project,.csproj, using a notepad and delete that missing file reference.

What is %timeit in python?

Line magics are prefixed with the % character and work much like OS command-line calls: they get as an argument the rest of the line, where arguments are passed without parentheses or quotes. Cell magics are prefixed with a double %%, and they are functions that get as an argument not only the rest of the line, but also the lines below it in a separate argument.

How do I replace all the spaces with %20 in C#?

To properly escape spaces as well as the rest of the special characters, use System.Uri.EscapeDataString(string stringToEscape).

Unsupported method: BaseConfig.getApplicationIdSuffix()

Alright I figured out how to fix this issue.

  • Open build.gradle and change the gradle version to the recommended version:
    classpath 'com.android.tools.build:gradle:1.3.0' to
    classpath 'com.android.tools.build:gradle:2.3.2'
  • Hit 'Try Again'
  • In the messages box it'll say 'Fix Gradle Wrapper and re-import project' Click that, since the minimum gradle version is 3.3
  • A new error will popup and say The SDK Build Tools revision (23.0.1) is too low for project ':app'. Minimum required is 25.0.0 - Hit Update Build Tools version and sync project
  • A window may popup that says Android Gradle Plugin Update recommended, just update from there.

Now the project should be runnable now on any of your android virtual devices.

how does unix handle full path name with space and arguments?

I would also like to point out that in case you are using command line arguments as part of a shell script (.sh file), then within the script, you would need to enclose the argument in quotes. So if your command looks like

>scriptName.sh arg1 arg2

And arg1 is your path that has spaces, then within the shell script, you would need to refer to it as "$arg1" instead of $arg1

Here are the details

Insert picture into Excel cell

Now we can add a picture to Excel directly and easely. Just follow these instructions:

  1. Go to the Insert tab.
  2. Click on the Pictures option (it’s in the illustrations group). image1
  3. In the ‘Insert Picture’ dialog box, locate the pictures that you want to insert into a cell in Excel. image2
  4. Click on the Insert button. image3
  5. Re-size the picture/image so that it can fit perfectly within the cell. image4
  6. Place the picture in the cell. A cool way to do this is to first press the ALT key and then move the picture with the mouse. It will snap and arrange itself with the border of the cell as soon it comes close to it.

If you have multiple images, you can select and insert all the images at once (as shown in step 4).

You can also resize images by selecting it and dragging the edges. In the case of logos or product images, you may want to keep the aspect ratio of the image intact. To keep the aspect ratio intact, use the corners of an image to resize it.


When you place an image within a cell using the steps above, it will not stick with the cell in case you resize, filter, or hide the cells. If you want the image to stick to the cell, you need to lock the image to the cell it’s placed n.

To do this, you need to follow the additional steps as shown below.

  1. Right-click on the picture and select Format Picture. image5
  2. In the Format Picture pane, select Size & Properties and with the options in Properties, select ‘Move and size with cells’. image6

Now you can move cells, filter it, or hide it, and the picture will also move/filter/hide.


NOTE:

This answer was taken from this link: Insert Picture into a Cell in Excel.

How can I scroll to a specific location on the page using jquery?

There is no need to use any plugin, you can do it like this:

var divPosition = $('#divId').offset();

then use this to scroll document to specific DOM:

$('html, body').animate({scrollTop: divPosition.top}, "slow");

using setTimeout on promise chain

If you are inside a .then() block and you want to execute a settimeout()

            .then(() => {
                console.log('wait for 10 seconds . . . . ');
                return new Promise(function(resolve, reject) { 
                    setTimeout(() => {
                        console.log('10 seconds Timer expired!!!');
                        resolve();
                    }, 10000)
                });
            })
            .then(() => {
                console.log('promise resolved!!!');

            })

output will as shown below

wait for 10 seconds . . . .
10 seconds Timer expired!!!
promise resolved!!!

Happy Coding!

Excel VBA calling sub from another sub with multiple inputs, outputs of different sizes

VBA subs are no macros. A VBA sub can be a macro, but it is not a must.

The term "macro" is only used for recorded user actions. from these actions a code is generated and stored in a sub. This code is simple and do not provide powerful structures like loops, for example Do .. until, for .. next, while.. do, and others.

The more elegant way is, to design and write your own VBA code without using the macro features!

VBA is a object based and event oriented language. Subs, or bette call it "sub routines", are started by dedicated events. The event can be the pressing of a button or the opening of a workbook and many many other very specific events.

If you focus to VB6 and not to VBA, then you can state, that there is always a main-window or main form. This form is started if you start the compiled executable "xxxx.exe".

In VBA you have nothing like this, but you have a XLSM file wich is started by Excel. You can attach some code to the Workbook_Open event. This event is generated, if you open your desired excel file which is called a workbook. Inside the workbook you have worksheets.

It is useful to get more familiar with the so called object model of excel. The workbook has several events and methods. Also the worksheet has several events and methods.

In the object based model you have objects, that have events and methods. methods are action you can do with a object. events are things that can happen to an object. An objects can contain another objects, and so on. You can create new objects, like sheets or charts.

Inserting data into a MySQL table using VB.NET

Dim connString as String ="server=localhost;userid=root;password=123456;database=uni_park_db"
Dim conn as MySqlConnection(connString)
Dim cmd as MysqlCommand
Dim dt as New DataTable
Dim ireturn as Boolean

Private Sub Insert_Car()

Dim sql as String = "insert into members_car (car_id, member_id, model, color, chassis_id, plate_number, code) values (@car_id,@member_id,@model,@color,@chassis_id,@plate_number,@code)"

Dim cmd = new MySqlCommand(sql, conn)

    cmd.Paramaters.AddwithValue("@car_id", txtCar.Text)
    cmd.Paramaters.AddwithValue("@member_id", txtMember.Text)
    cmd.Paramaters.AddwithValue("@model", txtModel.Text)
    cmd.Paramaters.AddwithValue("@color", txtColor.Text)
    cmd.Paramaters.AddwithValue("@chassis_id", txtChassis.Text)
    cmd.Paramaters.AddwithValue("@plate_number", txtPlateNo.Text)
    cmd.Paramaters.AddwithValue("@code", txtCode.Text)

    Try
        conn.Open()
        If cmd.ExecuteNonQuery() > 0 Then
            ireturn = True
        End If  
        conn.Close()


    Catch ex as Exception
        ireturn = False
        conn.Close()
    End Try

Return ireturn

End Sub

Browse files and subfolders in Python

I had a similar thing to work on, and this is how I did it.

import os

rootdir = os.getcwd()

for subdir, dirs, files in os.walk(rootdir):
    for file in files:
        #print os.path.join(subdir, file)
        filepath = subdir + os.sep + file

        if filepath.endswith(".html"):
            print (filepath)

Hope this helps.

How to create JSON Object using String?

JSONArray may be what you want.

String message;
JSONObject json = new JSONObject();
json.put("name", "student");

JSONArray array = new JSONArray();
JSONObject item = new JSONObject();
item.put("information", "test");
item.put("id", 3);
item.put("name", "course1");
array.put(item);

json.put("course", array);

message = json.toString();

// message
// {"course":[{"id":3,"information":"test","name":"course1"}],"name":"student"}

How can I zoom an HTML element in Firefox and Opera?

does this work correctly for you? :

zoom: 145%;
-moz-transform: scale(1.45);
-webkit-transform: scale(1.45);
scale(1.45);
transform: scale(1.45);

How to use opencv in using Gradle?

Since the integration of OpenCV is such an effort, we pre-packaged it and published it via JCenter here: https://github.com/quickbirdstudios/opencv-android

Just include this in your module's build.gradle dependencies section

dependencies {
  implementation 'com.quickbirdstudios:opencv:3.4.1'
}

and this in your project's build.gradle repositories section

repositories {
  jcenter()
}

You won't get lint error after gradle import but don't forget to initialize the OpenCV library like this in MainActivity

public class MainActivity extends Activity {
    static {
        if (!OpenCVLoader.initDebug())
            Log.d("ERROR", "Unable to load OpenCV");
        else
            Log.d("SUCCESS", "OpenCV loaded");
    }
...
...
...
...

How to use PrimeFaces p:fileUpload? Listener method is never invoked or UploadedFile is null / throws an error / not usable

Neither of the suggestions here were helpful for me. So I had to debug primefaces and found the reason of the problem was:

java.lang.IllegalStateException: No multipart config for servlet fileUpload

Then I have added section into my faces servlet in the web.xml. So that has fixed the problem:

<servlet>
    <servlet-name>main</servlet-name>

        <servlet-class>org.apache.myfaces.webapp.MyFacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
        <multipart-config>
            <location>/tmp</location>
            <max-file-size>20848820</max-file-size>
            <max-request-size>418018841</max-request-size>
            <file-size-threshold>1048576</file-size-threshold>
        </multipart-config>
    </servlet>

Has anyone ever got a remote JMX JConsole to work?

There are already some great answers here, but, there is a slightly simpler approach that I think it is worth sharing.

sushicutta's approach is good, but is very manual as you have to get the RMI Port every time. Thankfully, we can work around that by using a SOCKS proxy rather than explicitly opening the port tunnels. The downside of this approach is JMX app you run on your machine needs to be able to be configured to use a Proxy. Most processes you can do this from adding java properties, but, some apps don't support this.

Steps:

  1. Add the JMX options to the startup script for your remote Java service:

    -Dcom.sun.management.jmxremote=true
    -Dcom.sun.management.jmxremote.port=8090
    -Dcom.sun.management.jmxremote.ssl=false
    -Dcom.sun.management.jmxremote.authenticate=false
    
  2. Set up a SOCKS proxy connection to your remote machine:

    ssh -D 9696 [email protected]
    
  3. Configure your local Java monitoring app to use the SOCKS proxy (localhost:9696). Note: You can sometimes do this from the command line, i.e.:

    jconsole -J-DsocksProxyHost=localhost -J-DsocksProxyPort=9696
    

Reload activity in Android

Start with an intent your same activity and close the activity.

Intent refresh = new Intent(this, Main.class);
startActivity(refresh);//Start the same Activity
finish(); //finish Activity.

Visual Studio Community 2015 expiration date

There is and there isn't an expiration date. If you register Visual Studio 2015 Community Edition by successfully signing into Visual Studio then the product is fully unlocked with no set expiry date. If you don't sign in (or haven't entered a purchased licence key), you only have 30 day evaluation license.

You can check whether your copy of Visual Studio has is registered or not by selecting Help -> About Microsoft Studio and clicking on the "License Status" link in the upper right of the About dialog. If your product isn't registered you'll see something like this:

Visual Studio 2015 License Status Window

How to clear input buffer in C?

The lines:

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

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

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

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

ArrayList insertion and retrieval order

If you always add to the end, then each element will be added to the end and stay that way until you change it.

If you always insert at the start, then each element will appear in the reverse order you added them.

If you insert them in the middle, the order will be something else.

Uri content://media/external/file doesn't exist for some devices

Most probably it has to do with caching on the device. Catching the exception and ignoring is not nice but my problem was fixed and it seems to work.

How to format time since xxx e.g. “4 minutes ago” similar to Stack Exchange sites

I have modified Sky Sanders' version. The Math.floor(...) operations are evaluated in the if block

       var timeSince = function(date) {
            var seconds = Math.floor((new Date() - date) / 1000);
            var months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
            if (seconds < 5){
                return "just now";
            }else if (seconds < 60){
                return seconds + " seconds ago";
            }
            else if (seconds < 3600) {
                minutes = Math.floor(seconds/60)
                if(minutes > 1)
                    return minutes + " minutes ago";
                else
                    return "1 minute ago";
            }
            else if (seconds < 86400) {
                hours = Math.floor(seconds/3600)
                if(hours > 1)
                    return hours + " hours ago";
                else
                    return "1 hour ago";
            }
            //2 days and no more
            else if (seconds < 172800) {
                days = Math.floor(seconds/86400)
                if(days > 1)
                    return days + " days ago";
                else
                    return "1 day ago";
            }
            else{

                //return new Date(time).toLocaleDateString();
                return date.getDate().toString() + " " + months[date.getMonth()] + ", " + date.getFullYear();
            }
        }

Authenticating in PHP using LDAP through Active Directory

For those looking for a complete example check out http://www.exchangecore.com/blog/how-use-ldap-active-directory-authentication-php/.

I have tested this connecting to both Windows Server 2003 and Windows Server 2008 R2 domain controllers from a Windows Server 2003 Web Server (IIS6) and from a windows server 2012 enterprise running IIS 8.

Is there a Visual Basic 6 decompiler?

For the final, compiled code of your application, the short answer is “no”. Different tools are able to extract different information from the code (e.g. the forms setups) and there are P code decompilers (see Edgar's excellent link for such tools). However, up to this day, there is no decompiler for native code. I'm not aware of anything similar for other high-level languages either.

How to find where gem files are installed

This works and gives you the installed at path for each gem. This super helpful when trying to do multi-stage docker builds.. You can copy in the specific directory post-bundle install.

bash-4.4# gem list -d

Output::

aasm (5.0.6)
    Authors: Thorsten Boettger, Anil Maurya
    Homepage: https://github.com/aasm/aasm
    License: MIT
    Installed at: /usr/local/bundle

  State machine mixin for Ruby objects

two divs the same line, one dynamic width, one fixed

@Yijie; Check the link maybe that's you want http://jsfiddle.net/sandeep/NCkL4/7/

EDIT:

http://jsfiddle.net/sandeep/NCkL4/8/

OR SEE THE FOLLOWING SNIPPET

_x000D_
_x000D_
#parent{_x000D_
    overflow:hidden;_x000D_
    background:yellow;_x000D_
    position:relative;_x000D_
    display:table;_x000D_
}_x000D_
.left{_x000D_
    display:table-cell;_x000D_
}_x000D_
.right{_x000D_
    background:red;_x000D_
    width:50px;_x000D_
    height:100%;_x000D_
    display:table-cell;_x000D_
}_x000D_
body{_x000D_
    margin:0;_x000D_
    padding:0;_x000D_
}
_x000D_
<div id="parent">_x000D_
  <div class="left">Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</div>_x000D_
  <div class="right">fixed</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

'cout' was not declared in this scope

Use std::cout, since cout is defined within the std namespace. Alternatively, add a using std::cout; directive.

Bootstrap 3: Using img-circle, how to get circle from non-square image?

use this in css

.logo-center{
  border:inherit 8px #000000;
  -moz-border-radius-topleft: 75px;
  -moz-border-radius-topright:75px;
  -moz-border-radius-bottomleft:75px;
  -moz-border-radius-bottomright:75px;
  -webkit-border-top-left-radius:75px;
  -webkit-border-top-right-radius:75px;
  -webkit-border-bottom-left-radius:75px;
  -webkit-border-bottom-right-radius:75px;
  border-top-left-radius:75px;
  border-top-right-radius:75px;
  border-bottom-left-radius:75px;
  border-bottom-right-radius:75px;
}

<img class="logo-center"  src="NBC-Logo.png" height="60" width="60">

how to change text box value with jQuery?

Because you're trying to add a click event to a submit input you will need to prevent the normal flow that this will do that is submit the form.

You can also use $(document).ready()

But since you have your script tag at the end of the page the DOM is already loaded.

To prevent the default you will need something like this:

$("form").on('submit',function(e){
    e.preventDefault();
    $("#dsf").val("changed value")

})

If the element wasn't a submit input it will be as simple as

$("#cd").click(function(){
    $("#dsf").val("changed value")

})

See this Fiddle

Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'<>?,./

The most simple and shortest way to accomplish this:

/[^\p{L}\d\s@#]/u

Explanation

[^...] Match a single character not present in the list below

  • \p{L} => matches any kind of letter from any language

  • \d => matches a digit zero through nine

  • \s => matches any kind of invisible character

  • @# => @ and # characters

Don't forget to pass the u (unicode) flag.

How to show all privileges from a user in oracle?

To show all privileges:

select name from system_privilege_map;

Does the join order matter in SQL?

For INNER joins, no, the order doesn't matter. The queries will return same results, as long as you change your selects from SELECT * to SELECT a.*, b.*, c.*.


For (LEFT, RIGHT or FULL) OUTER joins, yes, the order matters - and (updated) things are much more complicated.

First, outer joins are not commutative, so a LEFT JOIN b is not the same as b LEFT JOIN a

Outer joins are not associative either, so in your examples which involve both (commutativity and associativity) properties:

a LEFT JOIN b 
    ON b.ab_id = a.ab_id
  LEFT JOIN c
    ON c.ac_id = a.ac_id

is equivalent to:

a LEFT JOIN c 
    ON c.ac_id = a.ac_id
  LEFT JOIN b
    ON b.ab_id = a.ab_id

but:

a LEFT JOIN b 
    ON  b.ab_id = a.ab_id
  LEFT JOIN c
    ON  c.ac_id = a.ac_id
    AND c.bc_id = b.bc_id

is not equivalent to:

a LEFT JOIN c 
    ON  c.ac_id = a.ac_id
  LEFT JOIN b
    ON  b.ab_id = a.ab_id
    AND b.bc_id = c.bc_id

Another (hopefully simpler) associativity example. Think of this as (a LEFT JOIN b) LEFT JOIN c:

a LEFT JOIN b 
    ON b.ab_id = a.ab_id          -- AB condition
 LEFT JOIN c
    ON c.bc_id = b.bc_id          -- BC condition

This is equivalent to a LEFT JOIN (b LEFT JOIN c):

a LEFT JOIN  
    b LEFT JOIN c
        ON c.bc_id = b.bc_id          -- BC condition
    ON b.ab_id = a.ab_id          -- AB condition

only because we have "nice" ON conditions. Both ON b.ab_id = a.ab_id and c.bc_id = b.bc_id are equality checks and do not involve NULL comparisons.

You can even have conditions with other operators or more complex ones like: ON a.x <= b.x or ON a.x = 7 or ON a.x LIKE b.x or ON (a.x, a.y) = (b.x, b.y) and the two queries would still be equivalent.

If however, any of these involved IS NULL or a function that is related to nulls like COALESCE(), for example if the condition was b.ab_id IS NULL, then the two queries would not be equivalent.

How to disable and then enable onclick event on <div> with javascript

You can use the CSS property pointer-events to disable the click event on any element:

https://developer.mozilla.org/en-US/docs/Web/CSS/pointer-events

// To disable:    
document.getElementById('id').style.pointerEvents = 'none';
// To re-enable:
document.getElementById('id').style.pointerEvents = 'auto'; 
// Use '' if you want to allow CSS rules to set the value

Here is a JsBin: http://jsbin.com/oyAhuRI/1/edit

Most Pythonic way to provide global configuration variables in config.py?

A small variation on Husky's idea that I use. Make a file called 'globals' (or whatever you like) and then define multiple classes in it, as such:

#globals.py

class dbinfo :      # for database globals
    username = 'abcd'
    password = 'xyz'

class runtime :
    debug = False
    output = 'stdio'

Then, if you have two code files c1.py and c2.py, both can have at the top

import globals as gl

Now all code can access and set values, as such:

gl.runtime.debug = False
print(gl.dbinfo.username)

People forget classes exist, even if no object is ever instantiated that is a member of that class. And variables in a class that aren't preceded by 'self.' are shared across all instances of the class, even if there are none. Once 'debug' is changed by any code, all other code sees the change.

By importing it as gl, you can have multiple such files and variables that lets you access and set values across code files, functions, etc., but with no danger of namespace collision.

This lacks some of the clever error checking of other approaches, but is simple and easy to follow.

Parser Error Message: Could not load type 'TestMvcApplication.MvcApplication'

Follow these steps:

  1. Build
  2. Configuration Manager
  3. Put the AnyCPU project
  4. Back to generate
  5. Ready, after this just follow the same steps to pass it to x86 or x64

deny directory listing with htaccess

Options -Indexes perfectly works for me ,

here is .htaccess file :

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
        Options -MultiViews -Indexes <---- This Works for Me :)
    </IfModule>


   ....etc stuff

</IfModule>

Before : enter image description here

After :

enter image description here

ArrayList initialization equivalent to array initialization

Here is the closest you can get:

ArrayList<String> list = new ArrayList(Arrays.asList("Ryan", "Julie", "Bob"));

You can go even simpler with:

List<String> list = Arrays.asList("Ryan", "Julie", "Bob")

Looking at the source for Arrays.asList, it constructs an ArrayList, but by default is cast to List. So you could do this (but not reliably for new JDKs):

ArrayList<String> list = (ArrayList<String>)Arrays.asList("Ryan", "Julie", "Bob")

JavaScript inside an <img title="<a href='#' onClick='alert('Hello World!')>The Link</a>" /> possible?

<img title="<a href="javascript:alert('hello world')">The Link</a>" /> 

Easier way to create circle div than using an image?

Give width and height depending on the size but,keep both equal

_x000D_
_x000D_
.circle {_x000D_
  background-color: gray;_x000D_
  height: 400px;_x000D_
  width: 400px;_x000D_
  border-radius: 100%;_x000D_
}
_x000D_
<div class="circle">_x000D_
</div>
_x000D_
_x000D_
_x000D_

Check if value exists in Postgres array

unnest can be used as well. It expands array to a set of rows and then simply checking a value exists or not is as simple as using IN or NOT IN.

e.g.

  1. id => uuid

  2. exception_list_ids => uuid[]

select * from table where id NOT IN (select unnest(exception_list_ids) from table2)

Ordering by specific field value first

One way to give preference to specific rows is to add a large number to their priority. You can do this with a CASE statement:

  select id, name, priority
    from mytable
order by priority + CASE WHEN name='core' THEN 1000 ELSE 0 END desc

Demo: http://www.sqlfiddle.com/#!2/753ee/1

Test if a property is available on a dynamic variable

For me this works:

if (IsProperty(() => DynamicObject.MyProperty))
  ; // do stuff



delegate string GetValueDelegate();

private bool IsProperty(GetValueDelegate getValueMethod)
{
    try
    {
        //we're not interesting in the return value.
        //What we need to know is whether an exception occurred or not

        var v = getValueMethod();
        return v != null;
    }
    catch (RuntimeBinderException)
    {
        return false;
    }
    catch
    {
        return true;
    }
}

Where can I set path to make.exe on Windows?

I had issues for a whilst not getting Terraform commands to run unless I was in the directory of the exe, even though I set the path correctly.

For anyone else finding this issue, I fixed it by moving the environment variable higher than others!

How to add jQuery to an HTML page?

You need this code wrap in tags and put on the end of page. Or create JS file (for example test.js), write this code on it and put on the end of page this tag

How to execute a command prompt command from python

Taking some inspiration from Daren Thomas's answer (and edit), try this:

proc = subprocess.Popen('dir C:\\', shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
out, err = proc.communicate()

out will now contain the text output.

They key nugget here is that the subprocess module already provides you shell integration with shell=True, so you don't need to call cmd.exe directly.

As a reminder, if you're in Python 3, this is going to be bytes, so you may want to do out.decode() to convert to a string.

JavaScript CSS how to add and remove multiple CSS classes to an element

In modern browsers, the classList API is supported.

This allows for a (vanilla) JavaScript function like this:

var addClasses;

addClasses = function (selector, classArray) {
    'use strict';

    var className, element, elements, i, j, lengthI, lengthJ;

    elements = document.querySelectorAll(selector);

    // Loop through the elements
    for (i = 0, lengthI = elements.length; i < lengthI; i += 1) {
        element = elements[i];

        // Loop through the array of classes to add one class at a time
        for (j = 0, lengthJ = classArray.length; j < lengthJ; j += 1) {
            className = classArray[j];

            element.classList.add(className);
        }
    }
};

Modern browsers (not IE) support passing multiple arguments to the classList::add function, which would remove the need for the nested loop, simplifying the function a bit:

var addClasses;

addClasses = function (selector, classArray) {
    'use strict';

    var classList, className, element, elements, i, j, lengthI, lengthJ;

    elements = document.querySelectorAll(selector);

    // Loop through the elements
    for (i = 0, lengthI = elements.length; i < lengthI; i += 1) {
        element = elements[i];
        classList = element.classList;

        // Pass the array of classes as multiple arguments to classList::add
        classList.add.apply(classList, classArray);
    }
};

Usage

addClasses('.button', ['large', 'primary']);

Functional version

var addClassesToElement, addClassesToSelection;

addClassesToElement = function (element, classArray) {
    'use strict';

    classArray.forEach(function (className) {
       element.classList.add(className);
    });
};

addClassesToSelection = function (selector, classArray) {
    'use strict';

    // Use Array::forEach on NodeList to iterate over results.
    // Okay, since we’re not trying to modify the NodeList.
    Array.prototype.forEach.call(document.querySelectorAll(selector), function (element) {
        addClassesToElement(element, classArray)
    });
};

// Usage
addClassesToSelection('.button', ['button', 'button--primary', 'button--large'])

The classList::add function will prevent multiple instances of the same CSS class as opposed to some of the previous answers.

Resources on the classList API:

How to set margin with jquery?

try

el.css('margin-left',mrg+'px');

Create a directory if it does not exist and then create the files in that directory as well

Using java.nio.Path it would be quite simple -

public static Path createFileWithDir(String directory, String filename) {
        File dir = new File(directory);
        if (!dir.exists()) dir.mkdirs();
        return Paths.get(directory + File.separatorChar + filename);
    }

What does "hashable" mean in Python?

Anything that is not mutable (mutable means, likely to change) can be hashed. Besides the hash function to look for, if a class has it, by eg. dir(tuple) and looking for the __hash__ method, here are some examples

#x = hash(set([1,2])) #set unhashable
x = hash(frozenset([1,2])) #hashable
#x = hash(([1,2], [2,3])) #tuple of mutable objects, unhashable
x = hash((1,2,3)) #tuple of immutable objects, hashable
#x = hash()
#x = hash({1,2}) #list of mutable objects, unhashable
#x = hash([1,2,3]) #list of immutable objects, unhashable

List of immutable types:

int, float, decimal, complex, bool, string, tuple, range, frozenset, bytes

List of mutable types:

list, dict, set, bytearray, user-defined classes

Is it possible to define more than one function per file in MATLAB, and access them from outside that file?

You could also group functions in one main file together with the main function looking like this:

function [varargout] = main( subfun, varargin )
[varargout{1:nargout}] = feval( subfun, varargin{:} ); 

% paste your subfunctions below ....
function str=subfun1
str='hello'

Then calling subfun1 would look like this: str=main('subfun1')

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

Have in mind that clone() doesn't work out of the box. You will have to implement Cloneable and override the clone() method making in public.

There are a few alternatives, which are preferable (since the clone() method has lots of design issues, as stated in other answers), and the copy-constructor would require manual work:

How to convert array to SimpleXML

Just a edit on a function above, when a key is numeric, add a prefix "key_"

// initializing or creating array
$student_info = array(your array data);

// creating object of SimpleXMLElement
$xml_student_info = new SimpleXMLElement("<?xml version=\"1.0\"?><student_info></student_info>");

// function call to convert array to xml
array_to_xml($student,$xml_student_info);

//saving generated xml file
$xml_student_info->asXML('file path and name');


function array_to_xml($student_info, &$xml_student_info) {
     foreach($student_info as $key => $value) {
          if(is_array($value)) {
            if(!is_numeric($key)){
                $subnode = $xml_student_info->addChild("$key");
                array_to_xml($value, $subnode);
            }
            else{
                $subnode = $xml_student_info->addChild("key_$key");
                array_to_xml($value, $subnode);
            }
          }
          else {
               if(!is_numeric($key)){
                    $xml_student_info->addChild("$key","$value");
               }else{
                    $xml_student_info->addChild("key_$key","$value");
               }
          }
     }
}

Using union and order by clause in mysql

I got this working on a join plus union.

(SELECT 
   table1.column1,
   table1.column2,
   foo1.column4
 FROM table1, table2, foo1, table5
 WHERE table5.somerecord = table1.column1
 ORDER BY table1.column1 ASC, table1.column2 DESC
)

UNION

(SELECT
    ... Another complex query as above
)

ORDER BY column1 DESC, column2 ASC

How to export SQL Server 2005 query to CSV

set nocount on

the quotes are there, use -w2000 to keep each row on one line.

Easy login script without database

Save the username and password hashes in array in a php file instead of db.

When you need to authenticate the user, compute hashes of his credentials and then compare them to hashes in array.

If you use safe hash function (see hash function and hash algos in PHP documentation), it should be pretty safe (you may consider using salted hash) and also add some protections to the form itself.

LINUX: Link all files from one to another directory

ln -s /mnt/usr/lib/* /usr/lib/

I guess, this belongs to superuser, though.

Java - Convert String to valid URI object

You can use the multi-argument constructors of the URI class. From the URI javadoc:

The multi-argument constructors quote illegal characters as required by the components in which they appear. The percent character ('%') is always quoted by these constructors. Any other characters are preserved.

So if you use

URI uri = new URI("http", "www.google.com?q=a b");

Then you get http:www.google.com?q=a%20b which isn't quite right, but it's a little closer.

If you know that your string will not have URL fragments (e.g. http://example.com/page#anchor), then you can use the following code to get what you want:

String s = "http://www.google.com?q=a b";
String[] parts = s.split(":",2);
URI uri = new URI(parts[0], parts[1], null);

To be safe, you should scan the string for # characters, but this should get you started.

HTML form do some "action" when hit submit button

index.html

<!DOCTYPE html>
<html>
   <body>
       <form action="submit.php" method="POST">
         First name: <input type="text" name="firstname" /><br /><br />
         Last name: <input type="text" name="lastname" /><br />
         <input type="submit" value="Submit" />
      </form> 
   </body>
</html>

After that one more file which page you want to display after pressing the submit button

submit.php

<html>
  <body>

    Your First Name is -  <?php echo $_POST["firstname"]; ?><br>
    Your Last Name is -   <?php echo $_POST["lastname"]; ?>

  </body>
</html>

method in class cannot be applied to given types

The generateNumbers(int[] numbers) function definition has arguments (int[] numbers)that expects an array of integers. However, in the main, generateNumbers(); doesn't have any arguments.

To resolve it, simply add an array of numbers to the arguments while calling thegenerateNumbers() function in the main.

Check Postgres access for a user

For all users on a specific database, do the following:

# psql
\c your_database
select grantee, table_catalog, privilege_type, table_schema, table_name from information_schema.table_privileges order by grantee, table_schema, table_name;

What is a callback URL in relation to an API?

A callback URL will be invoked by the API method you're calling after it's done. So if you call

POST /api.example.com/foo?callbackURL=http://my.server.com/bar

Then when /foo is finished, it sends a request to http://my.server.com/bar. The contents and method of that request are going to vary - check the documentation for the API you're accessing.

Algorithm to randomly generate an aesthetically-pleasing color palette

Use distinct-colors.

Written in javascript.

It generates a palette of visually distinct colors.

distinct-colors is highly configurable:

  • Choose how many colors are in the palette
  • Restrict the hue to a specific range
  • Restrict the chroma (saturation) to a specific range
  • Restrict the lightness to a specific range
  • Configure general quality of the palette

Find an element by class name, from a known parent element

var element = $("#parentDiv .myClassNameOfInterest")

How to pause for specific amount of time? (Excel/VBA)

this works flawlessly for me. insert any code before or after the "do until" loop. In your case, put the 5 lines (time1= & time2= & "do until" loop) at the end inside your do loop

sub whatever()
Dim time1, time2

time1 = Now
time2 = Now + TimeValue("0:00:01")
    Do Until time1 >= time2
        DoEvents
        time1 = Now()
    Loop

End sub

Typedef function pointer?

#include <stdio.h>
#include <math.h>

/*
To define a new type name with typedef, follow these steps:
1. Write the statement as if a variable of the desired type were being declared.
2. Where the name of the declared variable would normally appear, substitute the new type name.
3. In front of everything, place the keyword typedef.
*/

// typedef a primitive data type
typedef double distance;

// typedef struct 
typedef struct{
    int x;
    int y;
} point;

//typedef an array 
typedef point points[100]; 

points ps = {0}; // ps is an array of 100 point 

// typedef a function
typedef distance (*distanceFun_p)(point,point) ; // TYPE_DEF distanceFun_p TO BE int (*distanceFun_p)(point,point)

// prototype a function     
distance findDistance(point, point);

int main(int argc, char const *argv[])
{
    // delcare a function pointer 
    distanceFun_p func_p;

    // initialize the function pointer with a function address
    func_p = findDistance;

    // initialize two point variables 
    point p1 = {0,0} , p2 = {1,1};

    // call the function through the pointer
    distance d = func_p(p1,p2);

    printf("the distance is %f\n", d );

    return 0;
}

distance findDistance(point p1, point p2)
{
distance xdiff =  p1.x - p2.x;
distance ydiff =  p1.y - p2.y;

return sqrt( (xdiff * xdiff) + (ydiff * ydiff) );
}

Why does scanf() need "%lf" for doubles, when printf() is okay with just "%f"?

Because otherwise scanf will think you are passing a pointer to a float which is a smaller size than a double, and it will return an incorrect value.

How to backup a local Git repository?

came to this question via google.

Here is what i did in the simplest way.

git checkout branch_to_clone

then create a new git branch from this branch

git checkout -b new_cloned_branch
Switched to branch 'new_cloned_branch'

come back to original branch and continue:

git checkout branch_to_clone

Assuming you screwed up and need to restore something from backup branch :

git checkout new_cloned_branch -- <filepath>  #notice the space before and after "--"

Best part if anything is screwed up, you can just delete the source branch and move back to backup branch!!