Programs & Examples On #Qfile

A QFile is a class from the Qt Toolkit which provides an interface for reading from and writing to files.

Creating/writing into a new file in Qt

QFile file("test.txt");
/*
 *If file does not exist, it will be created
 */
if (!file.open(QIODevice::ReadOnly | QIODevice::Text | QIODevice::ReadWrite))
{
    qDebug() << "FAILED TO CREATE FILE / FILE DOES NOT EXIST";
}

/*for Reading line by line from text file*/
while (!file.atEnd()) {
    QByteArray line = file.readLine();
    qDebug() << "read output - " << line;
}

/*for writing line by line to text file */
if (file.open(QIODevice::ReadWrite))
{
    QTextStream stream(&file);
    stream << "1_XYZ"<<endl;
    stream << "2_XYZ"<<endl;
}

Qt - reading from a text file

You have to replace string line

QString line = in.readLine();

into while:

QFile file("/home/hamad/lesson11.txt");
if(!file.open(QIODevice::ReadOnly)) {
    QMessageBox::information(0, "error", file.errorString());
}

QTextStream in(&file);

while(!in.atEnd()) {
    QString line = in.readLine();    
    QStringList fields = line.split(",");    
    model->appendRow(fields);    
}

file.close();

remove objects from array by object property

var apps = [{id:34,name:'My App',another:'thing'},{id:37,name:'My New App',another:'things'}]

var removeIndex = apps.map(function(item) { return item.id; }).indexOf(37)

apps.splice(removeIndex, 1);

Insert NULL value into INT column

The optimal solution for this is provide it as '0' and while using string use it as 'null' when using integer.

ex:

INSERT INTO table_name(column_name) VALUES(NULL);

Sublime Text 2: How to delete blank/empty lines

There is a wonderful package (for Sublime 2 & 3) called 'Trimmer' which deletes empty lines. It also does many other useful things.

Refer this: https://packagecontrol.io/packages/Trimmer

jQuery datepicker set selected date, on the fly

or you can simply have

$('.date-pick').datePicker().val(new Date()).trigger('change')

How to display default text "--Select Team --" in combo box on pageload in WPF?

You can do this without any code behind by using a IValueConverter.

<Grid>
   <ComboBox
       x:Name="comboBox1"
       ItemsSource="{Binding MyItemSource}"  />
   <TextBlock
       Visibility="{Binding SelectedItem, ElementName=comboBox1, Converter={StaticResource NullToVisibilityConverter}}"
       IsHitTestVisible="False"
       Text="... Select Team ..." />
</Grid>

Here you have the converter class that you can re-use.

public class NullToVisibilityConverter : IValueConverter
{
    #region Implementation of IValueConverter

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value == null ? Visibility.Visible : Visibility.Collapsed;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    #endregion
}

And finally, you need to declare your converter in a resource section.

<Converters:NullToVisibilityConverter x:Key="NullToVisibilityConverter" />

Where Converters is the place you have placed the converter class. An example is:

xmlns:Converters="clr-namespace:MyProject.Resources.Converters"

The very nice thing about this approach is no repetition of code in your code behind.

How can I add new array elements at the beginning of an array in Javascript?

Using splice we insert an element to an array at the begnning:

arrName.splice( 0, 0, 'newName1' );

Parsing JSON using C

Json isn't a huge language to start with, so libraries for it are likely to be small(er than Xml libraries, at least).

There are a whole ton of C libraries linked at Json.org. Maybe one of them will work well for you.

Chmod 777 to a folder and all contents

If by all permissions you mean 777

Navigate to folder and

chmod -R 777 .

Easy way of running the same junit test over and over?

You could run your JUnit test from a main method and repeat it so many times you need:

package tests;

import static org.junit.Assert.*;

import org.junit.Test;
import org.junit.runner.Result;

public class RepeatedTest {

    @Test
    public void test() {
        fail("Not yet implemented");
    }

    public static void main(String args[]) {

        boolean runForever = true;

        while (runForever) {
            Result result = org.junit.runner.JUnitCore.runClasses(RepeatedTest.class);

            if (result.getFailureCount() > 0) {
                runForever = false;
               //Do something with the result object

            }
        }

    }

}

How do I use variables in Oracle SQL Developer?

Ok I know this a bit of a hack but this is a way to use a variable in a simple query, not a script:

WITH
    emplVar AS
    (SELECT 1234 AS id FROM dual)
SELECT
    *
FROM
    employees,
    emplVar
WHERE
    EmployId=emplVar.id;

You get to run it everywhere.

What is middleware exactly?

I always thought of it as the oldest software I have had to install. The total app used a web server, a database server, and an application server. The web server being the middleware between the data and the app.

IE11 meta element Breaks SVG

I ran into this issue and resolved it by removing the width styling I had used on the SVG:

.svg-div img {
    width: 200px; /* removed this */
    height: auto;
}

JavaScript private methods

In these situations when you have a public API, and you would like private and public methods/properties, I always use the Module Pattern. This pattern was made popular within the YUI library, and the details can be found here:

http://yuiblog.com/blog/2007/06/12/module-pattern/

It is really straightforward, and easy for other developers to comprehend. For a simple example:

var MYLIB = function() {  
    var aPrivateProperty = true;
    var aPrivateMethod = function() {
        // some code here...
    };
    return {
        aPublicMethod : function() {
            aPrivateMethod(); // okay
            // some code here...
        },
        aPublicProperty : true
    };  
}();

MYLIB.aPrivateMethod() // not okay
MYLIB.aPublicMethod() // okay

Why do we need to install gulp globally and locally?

TLDR; Here's why:

The reason this works is because gulp tries to run your gulpfile.js using your locally installed version of gulp, see here. Hence the reason for a global and local install of gulp.

Essentially, when you install gulp locally the script isn't in your PATH and so you can't just type gulp and expect the shell to find the command. By installing it globally the gulp script gets into your PATH because the global node/bin/ directory is most likely on your path.

To respect your local dependencies though, gulp will use your locally installed version of itself to run the gulpfile.js.

Global variables in header file

Don't initialize variables in headers. Put declaration in header and initialization in one of the c files.

In the header:

extern int i;

In file2.c:

int i=1;

How to calculate the 95% confidence interval for the slope in a linear regression model in R

Let's fit the model:

> library(ISwR)
> fit <- lm(metabolic.rate ~ body.weight, rmr)
> summary(fit)

Call:
lm(formula = metabolic.rate ~ body.weight, data = rmr)

Residuals:
    Min      1Q  Median      3Q     Max 
-245.74 -113.99  -32.05  104.96  484.81 

Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept) 811.2267    76.9755  10.539 2.29e-13 ***
body.weight   7.0595     0.9776   7.221 7.03e-09 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Residual standard error: 157.9 on 42 degrees of freedom
Multiple R-squared: 0.5539, Adjusted R-squared: 0.5433 
F-statistic: 52.15 on 1 and 42 DF,  p-value: 7.025e-09 

The 95% confidence interval for the slope is the estimated coefficient (7.0595) ± two standard errors (0.9776).

This can be computed using confint:

> confint(fit, 'body.weight', level=0.95)
               2.5 % 97.5 %
body.weight 5.086656 9.0324

MySQL Trigger after update only if row has changed

As a workaround, you could use the timestamp (old and new) for checking though, that one is not updated when there are no changes to the row. (Possibly that is the source for confusion? Because that one is also called 'on update' but is not executed when no change occurs) Changes within one second will then not execute that part of the trigger, but in some cases that could be fine (like when you have an application that rejects fast changes anyway.)

For example, rather than

IF NEW.a <> OLD.a or NEW.b <> OLD.b /* etc, all the way to NEW.z <> OLD.z */ 
THEN  
  INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b) ;
END IF

you could use

IF NEW.ts <> OLD.ts 
THEN  
  INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b) ;
END IF

Then you don't have to change your trigger every time you update the scheme (the issue you mentioned in the question.)

EDIT: Added full example

create table foo (a INT, b INT, ts TIMESTAMP);
create table bar (a INT, b INT);

INSERT INTO foo (a,b) VALUES(1,1);
INSERT INTO foo (a,b) VALUES(2,2);
INSERT INTO foo (a,b) VALUES(3,3);

DELIMITER ///

CREATE TRIGGER ins_sum AFTER UPDATE ON foo
    FOR EACH ROW
    BEGIN
        IF NEW.ts <> OLD.ts THEN  
            INSERT INTO bar (a, b) VALUES(NEW.a, NEW.b);
        END IF;
    END;
///

DELIMITER ;

select * from foo;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    1 |    1 | 2011-06-14 09:29:46 |
|    2 |    2 | 2011-06-14 09:29:46 |
|    3 |    3 | 2011-06-14 09:29:46 |
+------+------+---------------------+
3 rows in set (0.00 sec)

-- UPDATE without change
UPDATE foo SET b = 3 WHERE a = 3;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

-- the timestamo didnt change
select * from foo WHERE a = 3;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    3 |    3 | 2011-06-14 09:29:46 |
+------+------+---------------------+
1 rows in set (0.00 sec)

-- the trigger didn't run
select * from bar;
Empty set (0.00 sec)

-- UPDATE with change
UPDATE foo SET b = 4 WHERE a=3;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

-- the timestamp changed
select * from foo;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    1 |    1 | 2011-06-14 09:29:46 |
|    2 |    2 | 2011-06-14 09:29:46 |
|    3 |    4 | 2011-06-14 09:34:59 |
+------+------+---------------------+
3 rows in set (0.00 sec)

-- and the trigger ran
select * from bar;
+------+------+---------------------+
| a    | b    | ts                  |
+------+------+---------------------+
|    3 |    4 | 2011-06-14 09:34:59 |
+------+------+---------------------+
1 row in set (0.00 sec)

It is working because of mysql's behavior on handling timestamps. The time stamp is only updated if a change occured in the updates.

Documentation is here:
https://dev.mysql.com/doc/refman/5.7/en/timestamp-initialization.html

desc foo;
+-------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type      | Null | Key | Default           | Extra                       |
+-------+-----------+------+-----+-------------------+-----------------------------+
| a     | int(11)   | YES  |     | NULL              |                             |
| b     | int(11)   | YES  |     | NULL              |                             |
| ts    | timestamp | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------+-----------+------+-----+-------------------+-----------------------------+

Javascript: output current datetime in YYYY/mm/dd hh:m:sec format

I wrote a simple library for manipulating the JavaScript date object. You can try this:

var dateString = timeSolver.getString(new Date(), "YYYY/MM/DD HH:MM:SS.SSS")

Library here: https://github.com/sean1093/timeSolver

working with negative numbers in python

import time

print ('Two Digit Multiplication Calculator')
print ('===================================')
print ()
print ('Give me two numbers.')

x = int ( input (':'))

y = int ( input (':'))

z = 0

print ()


while x > 0:
    print (':',z)
    x = x - 1
    z = y + z
    time.sleep (.2)
    if x == 0:
        print ('Final answer: ',z)

while x < 0:
    print (':',-(z))
    x = x + 1
    z = y + z
    time.sleep (.2)
    if x == 0:
        print ('Final answer: ',-(z))

print ()  

What's the UIScrollView contentInset property for?

Content insets solve the problem of having content that goes underneath other parts of the User Interface and yet still remains reachable using scroll bars. In other words, the purpose of the Content Inset is to make the interaction area smaller than its actual area.

Consider the case where we have three logical areas of the screen:

TOP BUTTONS

TEXT

BOTTOM TAB BAR

and we want the TEXT to never appear transparently underneath the TOP BUTTONS, but we want the Text to appear underneath the BOTTOM TAB BAR and yet still allow scrolling so we could update the text sitting transparently under the BOTTOM TAB BAR.

Then we would set the top origin to be below the TOP BUTTONS, and the height to include the bottom of BOTTOM TAB BAR. To gain access to the Text sitting underneath the BOTTOM TAB BAR content we would set the bottom inset to be the height of the BOTTOM TAB BAR.

Without the inset, the scroller would not let you scroll up the content enough to type into it. With the inset, it is as if the content had extra "BLANK CONTENT" the size of the content inset. Blank text has been "inset" into the real "content" -- that's how I remember the concept.

Eclipse jump to closing brace

I found that if the chosen perspective doesn't match the type of the current file, then "go to matching brace" doesn't work. However, changing perspectives makes it work again. So, for example, when I have a PHP file open, but, say, the Java perspective active, pressing Ctrl + Shift + P does nothing. For the same file with the PHP perspective active, pressing Ctrl + Shift + P does exactly what you'd expect and puts my cursor beside the closing brace relative to the one it started at.

How to achieve ripple animation using support library?

I formerly voted to close this question as off-topic but actually I changed my mind as this is quite nice visual effect which, unfortunately, is not yet part of support library. It will most likely show up in future update, but there's no time frame announced.

Luckily there are few custom implementations already available:

including Materlial themed widget sets compatible with older versions of Android:

so you can try one of these or google for other "material widgets" or so...

sort json object in javascript

if(JSON.stringify(Object.keys(pcOrGroup).sort()) === JSON.stringify(Object.keys(orGroup)).sort())
{
    return true;
}

Unable to import path from django.urls

You need Django version 2

pip install --upgrade django
pip3 install --upgrade django

python -m django --version # 2.0.2
python3 -m django --version # 2.0.2

async/await - when to return a Task vs void?

The problem with calling async void is that

you don’t even get the task back. You have no way of knowing when the function’s task has completed. —— Crash course in async and await | The Old New Thing

Here are the three ways to call an async function:

async Task<T> SomethingAsync() { ... return t; }
async Task SomethingAsync() { ... }
async void SomethingAsync() { ... }

In all the cases, the function is transformed into a chain of tasks. The difference is what the function returns.

In the first case, the function returns a task that eventually produces the t.

In the second case, the function returns a task which has no product, but you can still await on it to know when it has run to completion.

The third case is the nasty one. The third case is like the second case, except that you don't even get the task back. You have no way of knowing when the function's task has completed.

The async void case is a "fire and forget": You start the task chain, but you don't care about when it's finished. When the function returns, all you know is that everything up to the first await has executed. Everything after the first await will run at some unspecified point in the future that you have no access to.

Selecting multiple classes with jQuery

// Due to this Code ): Syntax problem.    
$('.myClass', '.myOtherClass').removeClass('theclass'); 

According to jQuery documentation: https://api.jquery.com/multiple-selector/

When can select multiple classes in this way:

jQuery(“selector1, selector2, selectorN”) // double Commas. // IS valid.
jQuery('selector1, selector2, selectorN') // single Commas. // Is valid.

by enclosing all the selectors in a single '...' ' or double commas, "..."

So in your case the correct way to call multiple classes is:

$('.myClass', '.myOtherClass').removeClass('theclass'); // your Code // Invalid.
$('.myClass , .myOtherClass').removeClass('theclass');  // Correct Code // Is valid.

java.sql.SQLException: Exhausted Resultset

Try this:

if (rs != null && rs.first()) {
    do {
        count = rs.getInt(1);
    } while (rs.next());
}

How to test REST API using Chrome's extension "Advanced Rest Client"

in the header section you have to write

Authorization: Basic aG9sY67890vbGNpbQ==

where string after basic is the 64bit encoding value of your username:password. php example of getting the header values is: echo "Authorization: Basic " . base64_encode("myUser:myPassword");

n.b: I assumed your authentication method as basic. which can be different as well.

Django set field value after a form is initialized

Something like Nigel Cohen's would work if you were adding data to a copy of the collected set of form data:

form = FormType(request.POST)
if request.method == "POST":
    formcopy = form(request.POST.copy())
    formcopy.data['Email'] = GetEmailString()

jquery : focus to div is not working

you can use the below code to bring focus to a div, in this example the page scrolls to the <div id="navigation">

$('html, body').animate({ scrollTop: $('#navigation').offset().top }, 'slow');

Create a view with ORDER BY clause

I've had success forcing the view to be ordered using

SELECT TOP 9999999 ... ORDER BY something

Unfortunately using SELECT TOP 100 PERCENT does not work due the issue here.

AngularJS error: 'argument 'FirstCtrl' is not a function, got undefined'

I am not sure about this tutorial but I had the same problem when I forgot to include the file into grunt/gulp minimization process.

grunt.initConfig({
  uglify: {
    my_target: {
      files: {
        'dest/output.min.js': ['src/input1.js', 'src/missing_controller.js']
      }
    }
  }
});

Hope that helps.

Where to place and how to read configuration resource files in servlet based application?

Assume your code is looking for the file say app.properties. Copy this file to any dir and add this dir to classpath, by creating a setenv.sh in the bin dir of tomcat.

In your setenv.sh of tomcat( if this file is not existing, create one , tomcat will load this setenv.sh file. #!/bin/sh CLASSPATH="$CLASSPATH:/home/user/config_my_prod/"

You should not have your properties files in ./webapps//WEB-INF/classes/app.properties

Tomcat class loader will override the with the one from WEB-INF/classes/

A good read: https://tomcat.apache.org/tomcat-8.0-doc/class-loader-howto.html

Reset MySQL root password using ALTER USER statement after install on Mac

Had the problem after I installed mysql workbench and mysql community server. Got generated password during the server installation. Double clicking on the exisiting local instance in workbench triggered a dialog where I could set the new password.

Sqlite or MySql? How to decide?

My few cents to previous excellent replies. the site www.sqlite.org works on a sqlite database. Here is the link when the author (Richard Hipp) replies to a similar question.

jquery/javascript convert date string to date

If you only need it once, it's overkill to load a plugin.

For a date "dd/mm/yyyy", this works for me:

new Date(d.date.substring(6, 10),d.date.substring(3, 5)-1,d.date.substring(0, 2));

Just invert month and day for mm/dd/yyyy, the syntax is new Date(y,m,d)

How to change FontSize By JavaScript?

span.style.fontSize = "25px";

use this

How to use bluetooth to connect two iPhone?

Check out the BeamIt open source project. It will connect via bluetooth and WIFI (although it claims it does not do WIFI) and I have verified that it works well in my projects. It will allow peer to peer contact easily.

As for multiple connections, it is possible, but you will have to edit the BeamIt source code to make it possible. I suggest reading the GameKit programming guide

Search an Oracle database for tables with specific column names?

To find all tables with a particular column:

select owner, table_name from all_tab_columns where column_name = 'ID';

To find tables that have any or all of the 4 columns:

select owner, table_name, column_name
from all_tab_columns
where column_name in ('ID', 'FNAME', 'LNAME', 'ADDRESS');

To find tables that have all 4 columns (with none missing):

select owner, table_name
from all_tab_columns
where column_name in ('ID', 'FNAME', 'LNAME', 'ADDRESS')
group by owner, table_name
having count(*) = 4;

Where does Chrome store extensions?

This link "Finding All Installed Browsers in Windows XP and Vista – beware 64bit!" may be useful for Windows as suggested by "How to find all the browsers installed on a machine".

The installed web browsers are saved in this registry,

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet

HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Clients\StartMenuInternet.

How to add font-awesome to Angular 2 + CLI project

Edit: I'm using angular ^4.0.0 and Electron ^1.4.3

If you have issues with ElectronJS or similar and have a sort of 404 error, a possible workaround is to uedit your webpack.config.js, by adding (and by assuming that you have the font-awesome node module installed through npm or in the package.json file):

new CopyWebpackPlugin([
     { from: 'node_modules/font-awesome/fonts', to: 'assets' },
     { from: 'src/assets', to: 'assets' }
]),

Note that the webpack configuration I'm using has src/app/dist as output, and, in dist, an assets folder is created by webpack:

// our angular app
entry: {
    'polyfills': './src/polyfills.ts',
    'vendor': './src/vendor.ts',
    'app': './src/app/app',
},

// Config for our build files
output: {
    path: helpers.root('src/app/dist'),
    filename: '[name].js',
    sourceMapFilename: '[name].map',
    chunkFilename: '[id].chunk.js'
},

So basically, what is currently happening is:

  • Webpack is copying the fonts folder to the dev assets folder.
  • Webpack is copying the dev assets folder to the dist assets folder

Now, when the build process will be finished, the application will need to look for the .scss file and the folder containing the icons, resolving them properly. To resolve them, I've used this in my webpack config:

// support for fonts
{
    test: /\.(ttf|eot|svg|woff(2)?)(\?[a-z0-9=&.]+)?$/,
    loader: 'file-loader?name=dist/[name]-[hash].[ext]'
},

Finally, in the .scss file, I'm importing the font-awesome .scss and defining the path of the fonts, which is, again, dist/assets/font-awesome/fonts. The path is dist because in my webpack.config the output.path is set as helpers.root('src/app/dist');

So, in app.scss:

$fa-font-path: "dist/assets/font-awesome/fonts";
@import "~font-awesome/scss/font-awesome.scss";

Note that, in this way, it will define the font path (used later in the .scss file) and import the .scss file using ~font-awesome to resolve the font-awesome path in node_modules.

This is quite tricky, but it's the only way I've found to get around the 404 error issue with Electron.js

How do I change the figure size for a seaborn plot?

The top answers by Paul H and J. Li do not work for all types of seaborn figures. For the FacetGrid type (for instance sns.lmplot()), use the size and aspect parameter.

Size changes both the height and width, maintaining the aspect ratio.

Aspect only changes the width, keeping the height constant.

You can always get your desired size by playing with these two parameters.

Credit: https://stackoverflow.com/a/28765059/3901029

What parameters should I use in a Google Maps URL to go to a lat-lon?

In May 2017 Google announced the Google Maps URLs API that allows to construct universal cross-platform links. Now you can open Google maps on web, Android or iOS using the same URL string in form:

https://www.google.com/maps/search/?api=1&parameters

There are several modes that you can use: search, directions, show map and show street view.

So you can use something like

https://www.google.com/maps/search/?api=1&query=58.698017,-152.522067

to open map and place marker on some lat and lng.

For further details please refer to:

https://developers.google.com/maps/documentation/urls/guide

react-native - Fit Image in containing View, not the whole screen size

If you know the aspect ratio for example, if your image is square you can set either the height or the width to fill the container and get the other to be set by the aspectRatio property

Here is the style if you want the height be set automatically:

{
    width: '100%',
    height: undefined,
    aspectRatio: 1,
}

Note: height must be undefined

Formatting struct timespec

One way to format it is:

printf("%lld.%.9ld", (long long)ts.tv_sec, ts.tv_nsec);

MySQL Creating tables with Foreign Keys giving errno: 150

MySQL’s generic “errno 150” message “means that a foreign key constraint was not correctly formed.” As you probably already know if you are reading this page, the generic “errno: 150” error message is really unhelpful. However:

You can get the actual error message by running SHOW ENGINE INNODB STATUS; and then looking for LATEST FOREIGN KEY ERROR in the output.

For example, this attempt to create a foreign key constraint:

CREATE TABLE t1
(id INTEGER);

CREATE TABLE t2
(t1_id INTEGER,
 CONSTRAINT FOREIGN KEY (t1_id) REFERENCES t1 (id));

fails with the error Can't create table 'test.t2' (errno: 150). That doesn’t tell anyone anything useful other than that it’s a foreign key problem. But run SHOW ENGINE INNODB STATUS; and it will say:

------------------------
LATEST FOREIGN KEY ERROR
------------------------
130811 23:36:38 Error in foreign key constraint of table test/t2:
FOREIGN KEY (t1_id) REFERENCES t1 (id)):
Cannot find an index in the referenced table where the
referenced columns appear as the first columns, or column types
in the table and the referenced table do not match for constraint.

It says that the problem is it can’t find an index. SHOW INDEX FROM t1 shows that there aren’t any indexes at all for table t1. Fix that by, say, defining a primary key on t1, and the foreign key constraint will be created successfully.

How To Raise Property Changed events on a Dependency Property?

I ran into a similar problem where I have a dependency property that I wanted the class to listen to change events to grab related data from a service.

public static readonly DependencyProperty CustomerProperty = 
    DependencyProperty.Register("Customer", typeof(Customer),
        typeof(CustomerDetailView),
        new PropertyMetadata(OnCustomerChangedCallBack));

public Customer Customer {
    get { return (Customer)GetValue(CustomerProperty); }
    set { SetValue(CustomerProperty, value); }
}

private static void OnCustomerChangedCallBack(
        DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    CustomerDetailView c = sender as CustomerDetailView;
    if (c != null) {
        c.OnCustomerChanged();
    }
}

protected virtual void OnCustomerChanged() {
    // Grab related data.
    // Raises INotifyPropertyChanged.PropertyChanged
    OnPropertyChanged("Customer");
}

Regex: Check if string contains at least one digit

Ref this

SELECT * FROM product WHERE name REGEXP '[0-9]'

Vertical divider CSS

<div class="headerdivider"></div>

and

.headerdivider {
    border-left: 1px solid #38546d;
    background: #16222c;
    width: 1px;
    height: 80px;
    position: absolute;
    right: 250px;
    top: 10px;
}

Cannot open include file with Visual Studio

For me, it helped to link the projects current directory as such:

In the properties -> C++ -> General window, instead of linking the path to the file in "additional include directories". Put "." and uncheck "inheret from parent or project defaults".

Hope this helps.

How to use ES6 Fat Arrow to .filter() an array of objects

return arrayname.filter((rec) => rec.age > 18)

Write this in the method and call it

How to create an alert message in jsp page after submit process is complete

You can also create a new jsp file sayng that form is submited and in your main action file just write its file name

Eg. Your form is submited is in a file succes.jsp Then your action file will have

Request.sendRedirect("success.jsp")

'Syntax Error: invalid syntax' for no apparent reason

I noticed that invalid syntax error for no apparent reason can be caused by using space in:

print(f'{something something}')

Python IDLE seems to jump and highlight a part of the first line for some reason (even if the first line happens to be a comment), which is misleading.

Collection was modified; enumeration operation may not execute

Why this error?

In general .Net collections do not support being enumerated and modified at the same time. If you try to modify the collection list during enumeration, it raises an exception. So the issue behind this error is, we can not modify the list/dictionary while we are looping through the same.

One of the solutions

If we iterate a dictionary using a list of its keys, in parallel we can modify the dictionary object, as we are iterating through the key-collection and not the dictionary(and iterating its key collection).

Example

//get key collection from dictionary into a list to loop through
List<int> keys = new List<int>(Dictionary.Keys);

// iterating key collection using a simple for-each loop
foreach (int key in keys)
{
  // Now we can perform any modification with values of the dictionary.
  Dictionary[key] = Dictionary[key] - 1;
}

Here is a blog post about this solution.

And for a deep dive in StackOverflow: Why this error occurs?

What is the correct syntax of ng-include?

This worked for me:

ng-include src="'views/templates/drivingskills.html'"

complete div:

<div id="drivivgskills" ng-controller="DrivingSkillsCtrl" ng-view ng-include src="'views/templates/drivingskills.html'" ></div>

Why isn't textarea an input[type="textarea"]?

It was a limitation of the technology at the time it was created. My answer copied over from Programmers.SE:

From one of the original HTML drafts:

NOTE: In the initial design for forms, multi-line text fields were supported by the Input element with TYPE=TEXT. Unfortunately, this causes problems for fields with long text values. SGML's default (Reference Quantity Set) limits the length of attribute literals to only 240 characters. The HTML 2.0 SGML declaration increases the limit to 1024 characters.

What "wmic bios get serialnumber" actually retrieves?

wmic bios get serialnumber     

if run from a command line (start-run should also do the trick) prints out on screen the Serial Number of the product,
(for example in a toshiba laptop it would print out the serial number of the laptop.
with this serial number you can then identify your laptop model if you need ,from the makers service website-usually..:):)

I had to do exactly that.:):)

HTML select form with option to enter custom value

Using one of the above solutions ( @mickmackusa ), I made a working prototype in React 16.8+ using Hooks.

https://codesandbox.io/s/heuristic-dewdney-0h2y2

I hope it helps someone.

How to check if a line is blank using regex

Full credit to bchr02 for this answer. However, I had to modify it a bit to catch the scenario for lines that have */ (end of comment) followed by an empty line. The regex was matching the non empty line with */.

New: (^(\r\n|\n|\r)$)|(^(\r\n|\n|\r))|^\s*$/gm

All I did is add ^ as second character to signify the start of line.

How to format a floating number to fixed width in Python

You can also left pad with zeros. For example if you want number to have 9 characters length, left padded with zeros use:

print('{:09.3f}'.format(number))

Thus, if number = 4.656, the output is: 00004.656

For your example the output will look like this:

numbers  = [23.2300, 0.1233, 1.0000, 4.2230, 9887.2000]
for x in numbers: 
    print('{:010.4f}'.format(x))

prints:

00023.2300
00000.1233
00001.0000
00004.2230
09887.2000

One example where this may be useful is when you want to properly list filenames in alphabetical order. I noticed in some linux systems, the number is: 1,10,11,..2,20,21,...

Thus if you want to enforce the necessary numeric order in filenames, you need to left pad with the appropriate number of zeros.

Changing Underline color

I think the easiest way to do this is in your css, use:

text-decoration-color: red;

This will change the color of the underline without changing the color of your text. Good luck!

Accessing an array out of bounds gives no error, why?

It's undefined behavior as far as I know. Run a larger program with that and it will crash somewhere along the way. Bounds checking is not a part of raw arrays (or even std::vector).

Use std::vector with std::vector::iterator's instead so you don't have to worry about it.

Edit:

Just for fun, run this and see how long until you crash:

int main()
{
   int array[1];

   for (int i = 0; i != 100000; i++)
   {
       array[i] = i;
   }

   return 0; //will be lucky to ever reach this
}

Edit2:

Don't run that.

Edit3:

OK, here is a quick lesson on arrays and their relationships with pointers:

When you use array indexing, you are really using a pointer in disguise (called a "reference"), that is automatically dereferenced. This is why instead of *(array[1]), array[1] automatically returns the value at that value.

When you have a pointer to an array, like this:

int array[5];
int *ptr = array;

Then the "array" in the second declaration is really decaying to a pointer to the first array. This is equivalent behavior to this:

int *ptr = &array[0];

When you try to access beyond what you allocated, you are really just using a pointer to other memory (which C++ won't complain about). Taking my example program above, that is equivalent to this:

int main()
{
   int array[1];
   int *ptr = array;

   for (int i = 0; i != 100000; i++, ptr++)
   {
       *ptr++ = i;
   }

   return 0; //will be lucky to ever reach this
}

The compiler won't complain because in programming, you often have to communicate with other programs, especially the operating system. This is done with pointers quite a bit.

Generate Json schema from XML schema (XSD)

Disclaimer: I'm the author of jgeXml.

jgexml has Node.js based utility xsd2json which does a transformation between an XML schema (XSD) and a JSON schema file.

As with other options, it's not a 1:1 conversion, and you may need to hand-edit the output to improve the JSON schema validation, but it has been used to represent a complex XML schema inside an OpenAPI (swagger) definition.

A sample of the purchaseorder.xsd given in another answer is rendered as:

"PurchaseOrderType": {
  "type": "object",
  "properties": {
    "shipTo": {
      "$ref": "#/definitions/USAddress"
    },
    "billTo": {
      "$ref": "#/definitions/USAddress"
    },
    "comment": {
      "$ref": "#/definitions/comment"
    },
    "items": {
      "$ref": "#/definitions/Items"
    },
    "orderDate": {
      "type": "string",
      "pattern": "^[0-9]{4}-[0-9]{2}-[0-9]{2}.*$"
    }
  },

Check whether variable is number or string in JavaScript

For detecting numbers, the following passage from JavaScript: The Good Parts by Douglas Crockford is relevant:

The isFinite function is the best way of determining whether a value can be used as a number because it rejects NaN and Infinity . Unfortunately, isFinite will attempt to convert its operand to a number, so it is not a good test if a value is not actually a number. You may want to define your own isNumber function:

var isNumber = function isNumber(value) { return typeof value === 'number' &&
            isFinite(value);
};

Excel VBA, error 438 "object doesn't support this property or method

The Error is here

lastrow = wsPOR.Range("A" & Rows.Count).End(xlUp).Row + 1

wsPOR is a workbook and not a worksheet. If you are working with "Sheet1" of that workbook then try this

lastrow = wsPOR.Sheets("Sheet1").Range("A" & _
          wsPOR.Sheets("Sheet1").Rows.Count).End(xlUp).Row + 1

Similarly

wsPOR.Range("A2:G" & lastrow).Select

should be

wsPOR.Sheets("Sheet1").Range("A2:G" & lastrow).Select

Disabling and enabling a html input button

You can do this fairly easily with just straight JavaScript, no libraries required.

Enable a button

document.getElementById("Button").disabled=false;

Disable a button

 document.getElementById("Button").disabled=true;

No external libraries necessary.

How do I ignore files in Subversion?

What worked for me (I am using TortoiseSVN v1.13.1):

How do I ignore files in Subversion?

1.In File Explorer, right-click on SVN project folder-name
2.Click on "SVN Commit..."
3.A "commit" window will appear
4.Right-click on the folder/file that you want to ignore
5.Click on "Add to ignore list"
6.Select the folder/file name you want to ignore

  • There's a few choices(4 for me), if you choose only the folder/file name, it will be added to svn:ignore list
  • if you choose the folder/file name, with (recursively), it will be added to svn:global-ignores. This is what i normally choose, as this change is inherited automatically by all sub-directories. enter image description here

7.Commit the "property change" to SVN

Also, how do I find files which are not under version control?

After Step 3 above, click on "Show unversioned files" as follows:
enter image description here

How to use executeReader() method to retrieve the value of just one cell

It is not recommended to use DataReader and Command.ExecuteReader to get just one value from the database. Instead, you should use Command.ExecuteScalar as following:

String sql = "SELECT ColumnNumber FROM learer WHERE learer.id = " + index;
SqlCommand cmd = new SqlCommand(sql,conn);
learerLabel.Text = (String) cmd.ExecuteScalar();

Here is more information about Connecting to database and managing data.

scp from remote host to local host

There must be a user in the AllowUsers section, in the config file /etc/ssh/ssh_config, in the remote machine. You might have to restart sshd after editing the config file.

And then you can copy for example the file "test.txt" from a remote host to the local host

scp [email protected]:test.txt /local/dir


@cool_cs you can user ~ symbol ~/Users/djorge/Desktop if it's your home dir.

In UNIX, absolute paths must start with '/'.

Continuous Integration vs. Continuous Delivery vs. Continuous Deployment

Difference between Continuous Integration, Continuous delivery and continuous deployment

enter image description here

How to add an image to a JPanel?

I'm doing something very similar in a private project I'm working on. Thus far I've generated images up to 1024x1024 without any problems (except memory) and can display them very quickly and without any performance problems.

Overriding the paint method of JPanel subclass is overkill and requires more work than you need to do.

The way I do it is:

Class MapIcon implements Icon {...}

OR

Class MapIcon extends ImageIcon {...}

The code you use to generate the image will be in this class. I use a BufferedImage to draw onto then when the paintIcon() is called, use g.drawImvge(bufferedImage); This reduces the amount of flashing done while you generate your images, and you can thread it.

Next I extend JLabel:

Class MapLabel extends Scrollable, MouseMotionListener {...}

This is because I want to put my image on a scroll pane, I.e. display part of the image and have the user scroll around as needed.

So then I use a JScrollPane to hold the MapLabel, which contains only the MapIcon.

MapIcon map = new MapIcon (); 
MapLabel mapLabel = new MapLabel (map);
JScrollPane scrollPane = new JScrollPane();

scrollPane.getViewport ().add (mapLabel);

But for your scenario (just show the whole image every time). You need to add the MapLabel to the top JPanel, and make sure to size them all to the full size of the image (by overriding the GetPreferredSize()).

Using FileSystemWatcher to monitor a directory

The reason may be that watcher is declared as local variable to a method and it is garbage collected when the method finishes. You should declare it as a class member. Try the following:

FileSystemWatcher watcher;

private void watch()
{
  watcher = new FileSystemWatcher();
  watcher.Path = path;
  watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
                         | NotifyFilters.FileName | NotifyFilters.DirectoryName;
  watcher.Filter = "*.*";
  watcher.Changed += new FileSystemEventHandler(OnChanged);
  watcher.EnableRaisingEvents = true;
}

private void OnChanged(object source, FileSystemEventArgs e)
{
  //Copies file to another directory.
}

How can I convert a date to GMT?

After searching for an hour or two ,I've found a simple solution below.

const date = new Date(`${date from client} GMT`);

inside double ticks, there is a date from client side plust GMT.

I'm first time commenting, constructive criticism will be welcomed.

Calling JMX MBean method from a shell script

I'm not sure about bash-like environment. You might try some simple wrapper programs in Java (with program arguments) that invoke your MBeans on the remote server. You can then call these wrappers from the shell script

If you can use something like Python or Perl, you might be interested in JSR-262 which allows you to expose JMX operations over web services. This is scheduled to be included in Java 7 but you might be able to use a release candidate of the reference implementation

Add newly created specific folder to .gitignore in Git

It's /public_html/stats/*.

$ ~/myrepo> ls public_html/stats/
bar baz foo
$ ~/myrepo> cat .gitignore 
public_html/stats/*
$ ~/myrepo> git status
# On branch master
#
# Initial commit
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#   .gitignore
nothing added to commit but untracked files present (use "git add" to track)
$ ~/myrepo>

How to set focus on an input field after rendering?

Ref. @Dave's comment on @Dhiraj's answer; an alternative is to use the callback functionality of the ref attribute on the element being rendered (after a component first renders):

<input ref={ function(component){ React.findDOMNode(component).focus();} } />

More info

How do you get the path to the Laravel Storage folder?

In Laravel 3, call path('storage').

In Laravel 4, use the storage_path() helper function.

Disable Laravel's Eloquent timestamps

If you are using 5.5.x:

const UPDATED_AT = null;

And for 'created_at' field, you can use:

const CREATED_AT = null;

Make sure you are on the newest version. (This was broken in Laravel 5.5.0 and fixed again in 5.5.5).

react native get TextInput value

This piece of code worked for me. What I was missing was I was not passing 'this' in button action:

 onPress={this._handlePress.bind(this)}>
--------------

  _handlePress(event) {
console.log('Pressed!');

 var username = this.state.username;
 var password = this.state.password;

 console.log(username);
 console.log(password);
}

  render() {
    return (
      <View style={styles.container}>

      <TextInput
      ref="usr"
      style={{height: 40, borderColor: 'gray', borderWidth: 1 , marginTop: 10 , padding : 10 , marginLeft : 5 , marginRight : 5 }}
      placeHolder= "Enter username "
      placeholderTextColor = '#a52a2a'

      returnKeyType = {"next"}
      autoFocus = {true}
      autoCapitalize = "none"
      autoCorrect = {false}
      clearButtonMode = 'while-editing'
      onChangeText={(text) => {
          this.setState({username:text});
        }}
      onSubmitEditing={(event) => {
     this.refs.psw.focus();

      }}
      />

      <TextInput
      ref="psw"
      style={{height: 40, borderColor: 'gray', borderWidth: 1 , marginTop: 10,marginLeft : 5 , marginRight : 5}}
      placeholder= "Enter password"
      placeholderTextColor = '#a52a2a'
      autoCapitalize = "none"
      autoCorrect = {false}
      returnKeyType = {'done'}
      secureTextEntry = {true}
      clearButtonMode = 'while-editing'
      onChangeText={(text) => {
          this.setState({password:text});
        }}
      />

      <Button
        style={{borderWidth: 1, borderColor: 'blue'}}
        onPress={this._handlePress.bind(this)}>
        Login
      </Button>

      </View>
    );``
  }
}

Failed to resolve: com.android.support:appcompat-v7:26.0.0

1 - in build.gradle change my supportLibVersion to 26.0.0

2 - in app/build.gradle use :

implementation "com.android.support:appcompat v7:${rootProject.ext.supportLibVersion}"

3 - cd android

4 - ./gradlew clean

5 - ./gradlew assembleRelease

Merge two json/javascript arrays in to one array

You want the concat method.

var finalObj = json1.concat(json2);

How to load data to hive from HDFS without removing the source file?

from your question I assume that you already have your data in hdfs. So you don't need to LOAD DATA, which moves the files to the default hive location /user/hive/warehouse. You can simply define the table using the externalkeyword, which leaves the files in place, but creates the table definition in the hive metastore. See here: Create Table DDL eg.:

create external table table_name (
  id int,
  myfields string
)
location '/my/location/in/hdfs';

Please note that the format you use might differ from the default (as mentioned by JigneshRawal in the comments). You can use your own delimiter, for example when using Sqoop:

row format delimited fields terminated by ','

How to present a simple alert message in java?

Call "setWarningMsg()" Method and pass the text that you want to show.

exm:- setWarningMsg("thank you for using java");


public static void setWarningMsg(String text){
    Toolkit.getDefaultToolkit().beep();
    JOptionPane optionPane = new JOptionPane(text,JOptionPane.WARNING_MESSAGE);
    JDialog dialog = optionPane.createDialog("Warning!");
    dialog.setAlwaysOnTop(true);
    dialog.setVisible(true);
}

Or Just use

JOptionPane optionPane = new JOptionPane("thank you for using java",JOptionPane.WARNING_MESSAGE);
JDialog dialog = optionPane.createDialog("Warning!");
dialog.setAlwaysOnTop(true); // to show top of all other application
dialog.setVisible(true); // to visible the dialog

You can use JOptionPane. (WARNING_MESSAGE or INFORMATION_MESSAGE or ERROR_MESSAGE)

CASE WHEN statement for ORDER BY clause

declare @OrderByCmd  nvarchar(2000)
declare @OrderByName nvarchar(100)
declare @OrderByCity nvarchar(100)
set @OrderByName='Name'    
set @OrderByCity='city'
set @OrderByCmd= 'select * from customer Order By '+@OrderByName+','+@OrderByCity+''
EXECUTE sp_executesql @OrderByCmd 

Make UINavigationBar transparent

The below code expands upon the top answer chosen for this thread, to get rid of the bottom border and set text color:

  1. The last two coded lines of this code set transparency. I borrowed that code from this thread and it worked perfectly!

  2. The "clipsToBounds" property was code I found which got rid of the bottom border line with OR without transparency set (so if you decide to go with a solid white/black/etc. background instead, there will still be no border line).

  3. The "tintColor" line (2nd coded line) set my back button to a light grey

  4. I kept barTintColor as a backup. I don't know why transparency would not work, but if it doesn't, I want my bg white as I used to have it

    let navigationBarAppearace = UINavigationBar.appearance()
    navigationBarAppearace.tintColor = UIColor.lightGray
    navigationBarAppearace.barTintColor = UIColor.white
    navigationBarAppearace.clipsToBounds = true
    navigationBarAppearace.isTranslucent = true
    navigationBarAppearace.setBackgroundImage(UIImage(), for: .default)
    navigationBarAppearace.shadowImage = UIImage()
    

Java - Create a new String instance with specified length and filled with specific character. Best solution?

You can use a while loop like this:

String text = "Hello";
while (text.length() < 10) { text += "*"; }
System.out.println(text);

Will give you:

Hello*****

Or get the same result with a custom method:

    public static String extendString(String text, String symbol, Integer len) {
        while (text.length() < len) { text += symbol; }
        return text;
    }

Then just call:

extendString("Hello", "*", 10)

It may also be a good idea to set a length check to prevent infinite loop.

Is there a REAL performance difference between INT and VARCHAR primary keys?

For short codes, there's probably no difference. This is especially true as the table holding these codes are likely to be very small (a couple thousand rows at most) and not change often (when is the last time we added a new US State).

For larger tables with a wider variation among the key, this can be dangerous. Think about using e-mail address/user name from a User table, for example. What happens when you have a few million users and some of those users have long names or e-mail addresses. Now any time you need to join this table using that key it becomes much more expensive.

How to compare variables to undefined, if I don’t know whether they exist?

!undefined is true in javascript, so if you want to know whether your variable or object is undefined and want to take actions, you could do something like this:

if(<object or variable>) {
     //take actions if object is not undefined
} else {
     //take actions if object is undefined
}

Difference between no-cache and must-revalidate

I think there is a difference between max-age=0, must-revalidate and no-cache:

In the must-revalidate case the client is allowed to send a If-Modified-Since request and serve the response from cache if 304 Not Modified is returned.

In the no-cache case, the client must not cache the response, so should not use If-Modified-Since.

Java AES encryption and decryption

If for a block cipher you're not going to use a Cipher transformation that includes a padding scheme, you need to have the number of bytes in the plaintext be an integral multiple of the block size of the cipher.

So either pad out your plaintext to a multiple of 16 bytes (which is the AES block size), or specify a padding scheme when you create your Cipher objects. For example, you could use:

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

Unless you have a good reason not to, use a padding scheme that's already part of the JCE implementation. They've thought out a number of subtleties and corner cases you'll have to realize and deal with on your own otherwise.


Ok, your second problem is that you are using String to hold the ciphertext.

In general,

String s = new String(someBytes);
byte[] retrievedBytes = s.getBytes();

will not have someBytes and retrievedBytes being identical.

If you want/have to hold the ciphertext in a String, base64-encode the ciphertext bytes first and construct the String from the base64-encoded bytes. Then when you decrypt you'll getBytes() to get the base64-encoded bytes out of the String, then base64-decode them to get the real ciphertext, then decrypt that.

The reason for this problem is that most (all?) character encodings are not capable of mapping arbitrary bytes to valid characters. So when you create your String from the ciphertext, the String constructor (which applies a character encoding to turn the bytes into characters) essentially has to throw away some of the bytes because it can make no sense of them. Thus, when you get bytes out of the string, they are not the same bytes you put into the string.

In Java (and in modern programming in general), you cannot assume that one character = one byte, unless you know absolutely you're dealing with ASCII. This is why you need to use base64 (or something like it) if you want to build strings from arbitrary bytes.

Is there any boolean type in Oracle databases?

Not at the SQL level and that's a pity There is one in PLSQL though

JSONException: Value of type java.lang.String cannot be converted to JSONObject

I think the problem may be in the charset that you are trying to use. It is probably best to use UTF-8 instead of iso-8859-1.

Also open whatever file is being used for your InputStream and make sure no special characters were accidentally inserted. Sometimes you have to specifically tell your editor to display hidden / special characters.

Ruby optional parameters

You are almost always better off using an options hash.

def ldap_get(base_dn, filter, options = {})
  options[:scope] ||= LDAP::LDAP_SCOPE_SUBTREE
  ...
end

ldap_get(base_dn, filter, :attrs => X)

Creating a UIImage from a UIColor to use as a background image for UIButton

Are you using ARC? The problem here is that you don't have a reference to the UIColor object that you're trying to apply; the CGColor is backed by that UIColor, but ARC will deallocate the UIColor before you have a chance to use the CGColor.

The clearest solution is to have a local variable pointing to your UIColor with the objc_precise_lifetime attribute.

You can read more about this exact case on this article about UIColor and short ARC lifetimes or get more details about the objc_precise_lifetime attribute.

How to insert a large block of HTML in JavaScript?

The easiest way to insert html blocks is to use template strings (backticks). It will also allow you to insert dynamic content via ${...}:

document.getElementById("log-menu").innerHTML = `
            <a href="#"> 
               ${data.user.email}
            </a>
            <div class="dropdown-menu p-3 dropdown-menu-right">
                <div class="form-group">
                    <label for="email1">Logged in as:</label>
                    <p>${data.user.email}</p>
                </div>
                <button onClick="getLogout()" ">Sign out</button>
            </div>
    `

Create local maven repository

If maven is not creating Local Repository i.e .m2/repository folder then try below step.

In your Eclipse\Spring Tool Suite, Go to Window->preferences-> maven->user settings-> click on Restore Defaults-> Apply->Apply and close

lexical or preprocessor issue file not found occurs while archiving?

I had this same issue now and found that my sub-projects 'Public Header Folder Path' was set to an incorrect path (when compared with what my main project was using as its 'Header Search Path' and 'User Header Search Path').

e.g.

My main project had the following:

  • Header Search Paths
    • Debug "build/Debug-iphoneos/../../Headers"
    • Release "build/Debug-iphoneos/../../Headers"

And the same for the User Header Search Paths


Whereas my sub-project (dependency) had the following:

  • Public Header Folder Path
    • Debug "include/BoxSDK"
    • Release "include/BoxSDK"

Changing the 'Public Header Folder Path' to "../../Headers/BoxSDK" fixed the problem since the main project was already searching that folder ('../../Headers').

PS: I took some good screenshots, but I am not allowed to post an answer with images until I hit reputation 10 :(

Convert string in base64 to image and save on filesystem in Python

You can use Pillow.

pip install Pillow



image = base64.b64decode(str(base64String))       
fileName = 'test.jpeg'

imagePath = FILE_UPLOAD_DIR + fileName

img = Image.open(io.BytesIO(image))
img.save(imagePath, 'jpeg')
return fileName

reference for complete source code: https://abhisheksharma.online/convert-base64-blob-to-image-file-in-python/

CSS submit button weird rendering on iPad/iPhone

The above answer for webkit appearance worked, but the button still looked kind pale/dull compared to the browser on other devices/desktop. I also had to set opacity to full (ranges from 0 to 1)

-webkit-appearance:none;
opacity: 1

After setting the opacity, the button looked the same on all the different devices/emulator/desktop.

Interface vs Abstract Class (general OO)

By implementing interfaces you are achieving composition ("has-a" relationships) instead of inheritance ("is-a" relationships). That is an important principle to remember when it comes to things like design patterns where you need to use interfaces to achieve a composition of behaviors instead of an inheritance.

javascript cell number validation

Verify this code : It works on change of phone number field in ms crm 2016 form .

function validatePhoneNumber() {

    var mob = Xrm.Page.getAttribute("gen_phone").getValue();
    var length = mob.length;
    if (length < 10 || length > 10) {
        alert("Please Enter 10 Digit Number:");
        Xrm.Page.getAttribute("gen_phone").setValue(null);
        return true;
    }
    if (mob > 31 && (mob < 48 || mob > 57)) {} else {
        alert("Please Enter 10 Digit Number:");
        Xrm.Page.getAttribute("gen_phone").setValue(null);
        return true;
    }
}

How to find server name of SQL Server Management Studio

Open CMD

Run this

SQLCMD -L

You will get list of SQL Server instance

How to wait 5 seconds with jQuery?

setTimeout(function(){


},5000); 

Place your code inside of the { }

300 = 0.3 seconds

700 = 0.7 seconds

1000 = 1 second

2000= 2 seconds

2200 = 2.2 seconds

3500 = 3.5 seconds

10000 = 10 seconds

etc.

Stop absolutely positioned div from overlapping text

Put a z-indez of -1 on your absolute (or relative) positioned element.

This will pull it out of the stacking context. (I think.) Read more wonderful things about "stacking contexts" here: https://philipwalton.com/articles/what-no-one-told-you-about-z-index/

Compare cell contents against string in Excel

You can use the EXACT Function for exact string comparisons.

=IF(EXACT(A1, "ENG"), 1, 0)

HTML5 : Iframe No scrolling?

In HTML5 there is no scrolling attribute because "its function is better handled by CSS" see http://www.w3.org/TR/html5-diff/ for other changes. Well and the CSS solution:

CSS solution:

HTML4's scrolling="no" is kind of an alias of the CSS's overflow: hidden, to do so it is important to set size attributes width/height:

iframe.noScrolling{
  width: 250px; /*or any other size*/
  height: 300px; /*or any other size*/
  overflow: hidden;
}

Add this class to your iframe and you're done:

<iframe src="http://www.example.com/" class="noScrolling"></iframe>

! IMPORTANT NOTE ! : overflow: hidden for <iframe> is not fully supported by all modern browsers yet(even chrome doesn't support it yet) so for now (2013) it's still better to use Transitional version and use scrolling="no" and overflow:hidden at the same time :)

UPDATE 2020: the above is still true, oveflow for iframes is still not supported by all majors

AngularJS routing without the hash '#'

If you are wanting to configure this locally on OS X 10.8 serving Angular with Apache then you might find the following in your .htaccess file helps:

<IfModule mod_rewrite.c>
    Options +FollowSymlinks
    RewriteEngine On
    RewriteBase /~yourusername/appname/public/
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} !.*\.(css|js|html|png|jpg|jpeg|gif|txt)
    RewriteRule (.*) index.html [L]
</IfModule>

Options +FollowSymlinks if not set may give you a forbidden error in the logs like so:

Options FollowSymLinks or SymLinksIfOwnerMatch is off which implies that RewriteRule directive is forbidden

Rewrite base is required otherwise requests will be resolved to your server root which locally by default is not your project directory unless you have specifically configured your vhosts, so you need to set the path so that the request finds your project root directory. For example on my machine I have a /Users/me/Sites directory where I keep all my projects. Like the old OS X set up.

The next two lines effectively say if the path is not a directory or a file, so you need to make sure you have no files or directories the same as your app route paths.

The next condition says if request not ending with file extensions specified so add what you need there

And the [L] last one is saying to serve the index.html file - your app for all other requests.

If you still have problems then check the apache log, it will probably give you useful hints:

/private/var/log/apache2/error_log

Convert list to tuple in Python

You might have done something like this:

>>> tuple = 45, 34  # You used `tuple` as a variable here
>>> tuple
(45, 34)
>>> l = [4, 5, 6]
>>> tuple(l)   # Will try to invoke the variable `tuple` rather than tuple type.

Traceback (most recent call last):
  File "<pyshell#10>", line 1, in <module>
    tuple(l)
TypeError: 'tuple' object is not callable
>>>
>>> del tuple  # You can delete the object tuple created earlier to make it work
>>> tuple(l)
(4, 5, 6)

Here's the problem... Since you have used a tuple variable to hold a tuple (45, 34) earlier... So, now tuple is an object of type tuple now...

It is no more a type and hence, it is no more Callable.

Never use any built-in types as your variable name... You do have any other name to use. Use any arbitrary name for your variable instead...

Set the space between Elements in Row Flutter

To make an exact spacing, I use Padding. An example with two images:

Row(
    mainAxisAlignment: MainAxisAlignment.spaceAround,
    children: <Widget>[
      Expanded(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Image.asset('images/user1.png'),
        ),
      ),
      Expanded(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Image.asset('images/user2.png'),
        ),
      )
    ],
  ),

Difference between JSON.stringify and JSON.parse

Firstly, JSON.stringify() function converts a JavaScript value to a JavaScript Object Notation (JSON) string. JSON.parse() function converts a JavaScript Object Notation (JSON) string into an object. For more information about these two functions, please refer to the following links.

https://msdn.microsoft.com/library/cc836459(v=vs.94).aspx https://msdn.microsoft.com/library/cc836466(v=vs.94).aspx

Secondly, the following sample will be helpful for you to understand these two functions.

<form id="form1" runat="server">
    <div>
        <div id="result"></div>
    </div>
</form>

<script>
    $(function () {
        //define a json object
        var employee = { "name": "John Johnson", "street": "Oslo West 16", "phone": "555 1234567" };

        //use JSON.stringify to convert it to json string
        var jsonstring = JSON.stringify(employee);
        $("#result").append('<p>json string: ' + jsonstring + '</p>');

        //convert json string to json object using JSON.parse function
        var jsonobject = JSON.parse(jsonstring);
        var info = '<ul><li>Name:' + jsonobject.name + '</li><li>Street:' + jsonobject.street + '</li><li>Phone:' + jsonobject.phone + '</li></ul>';

        $("#result").append('<p>json object:</p>');
        $("#result").append(info);
    });
</script>

Getting fb.me URL

You can use bit.ly api to create facebook short urls find the documentation here http://api.bitly.com

How to combine class and ID in CSS selector?

There's nothing wrong with combining an id and a class on one element, but you shouldn't need to identify it by both for one rule. If you really want to you can do:

#content.sectionA{some rules}

You don't need the div in front of the ID as others have suggested.

In general, CSS rules specific to that element should be set with the ID, and those are going to carry a greater weight than those of just the class. Rules specified by the class would be properties that apply to multiple items that you don't want to change in multiple places anytime you need to adjust.

That boils down to this:

 .sectionA{some general rules here}
 #content{specific rules, and overrides for things in .sectionA}

Make sense?

How to escape % in String.Format?

Here's an option if you need to escape multiple %'s in a string with some already escaped.

(?:[^%]|^)(?:(%%)+|)(%)(?:[^%])

To sanitise the message before passing it to String.format, you can use the following

Pattern p = Pattern.compile("(?:[^%]|^)(?:(%%)+|)(%)(?:[^%])");
Matcher m1 = p.matcher(log);

StringBuffer buf = new StringBuffer();
while (m1.find())
    m1.appendReplacement(buf, log.substring(m1.start(), m1.start(2)) + "%%" + log.substring(m1.end(2), m1.end()));

// Return the sanitised message
String escapedString = m1.appendTail(buf).toString();

This works with any number of formatting characters, so it will replace % with %%, %%% with %%%%, %%%%% with %%%%%% etc.

It will leave any already escaped characters alone (e.g. %%, %%%% etc.)

How many concurrent AJAX (XmlHttpRequest) requests are allowed in popular browsers?

I have writen a single file AJAX tester. Enjoy it!!! Just because I have had problems with my hosting provider

<?php /*

Author:   Luis Siquot
Purpose:  Check ajax performance and errors
License:  GPL
site5:    Please don't drop json requests (nor delay)!!!!

*/

$r = (int)$_GET['r'];
$w = (int)$_GET['w'];
if($r) { 
   sleep($w);
   echo json_encode($_GET);
   die ();
}  //else
?><head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript">

var _settimer;
var _timer;
var _waiting;

$(function(){
  clearTable();
  $('#boton').bind('click', donow);
})

function donow(){
  var w;
  var estim = 0;
  _waiting = $('#total')[0].value * 1;
  clearTable();
  for(var r=1;r<=_waiting;r++){
       w = Math.floor(Math.random()*6)+2;
       estim += w;
       dodebug({r:r, w:w});
       $.ajax({url: '<?php echo $_SERVER['SCRIPT_NAME']; ?>',
               data:    {r:r, w:w},
               dataType: 'json',   // 'html', 
               type: 'GET',
               success: function(CBdata, status) {
                  CBdebug(CBdata);
               }
       });
  }
  doStat(estim);
  timer(estim+10);
}

function doStat(what){
    $('#stat').replaceWith(
       '<table border="0" id="stat"><tr><td>Request Time Sum=<th>'+what+
       '<td>&nbsp;&nbsp;/2=<th>'+Math.ceil(what/2)+
       '<td>&nbsp;&nbsp;/3=<th>'+Math.ceil(what/3)+
       '<td>&nbsp;&nbsp;/4=<th>'+Math.ceil(what/4)+
       '<td>&nbsp;&nbsp;/6=<th>'+Math.ceil(what/6)+
       '<td>&nbsp;&nbsp;/8=<th>'+Math.ceil(what/8)+
       '<td> &nbsp; (seconds)</table>'
    );
}

function timer(what){
  if(what)         {_timer = 0; _settimer = what;}
  if(_waiting==0)  {
    $('#showTimer')[0].innerHTML = 'completed in <b>' + _timer + ' seconds</b> (aprox)';
    return ;
  }
  if(_timer<_settimer){
     $('#showTimer')[0].innerHTML = _timer;
     setTimeout("timer()",1000);
     _timer++;
     return;
  }
  $('#showTimer')[0].innerHTML = '<b>don\'t wait any more!!!</b>';
}


function CBdebug(what){
    _waiting--;
    $('#req'+what.r)[0].innerHTML = 'x';
}


function dodebug(what){
    var tt = '<tr><td>' + what.r + '<td>' + what.w + '<td id=req' + what.r + '>&nbsp;'
    $('#debug').append(tt);
}


function clearTable(){
    $('#debug').replaceWith('<table border="1" id="debug"><tr><td>Request #<td>Wait Time<td>Done</table>');
}


</script>
</head>
<body>
<center>
<input type="button" value="start" id="boton">
<input type="text" value="80" id="total" size="2"> concurrent json requests
<table id="stat"><tr><td>&nbsp;</table>
Elapsed Time: <span id="showTimer"></span>
<table id="debug"></table>
</center>
</body>

Edit:
r means row and w waiting time.
When you initially press start button 80 (or any other number) of concurrent ajax request are launched by javascript, but as is known they are spooled by the browser. Also they are requested to the server in parallel (limited to certain number, this is the fact of this question). Here the requests are solved server side with a random delay (established by w). At start time all the time needed to solve all ajax calls is calculated. When test is finished, you can see if it took half, took third, took a quarter, etc of the total time, deducting which was the parallelism on the calls to the server. This is not strict, nor precise, but is nice to see in real time how ajaxs calls are completed (seeing the incoming cross). And is a very simple self contained script to show ajax basics.
Of course, this assumes, that server side is not introducing any extra limit.
Preferably use in conjunction with firebug net panel (or your browser's equivalent)

Background color on input type=button :hover state sticks in IE

Try using the type attribute selector to find buttons (maybe this'll fix it too):

input[type=button]
{
  background-color: #E3E1B8; 
}

input[type=button]:hover
{
  background-color: #46000D
}

Fiddler not capturing traffic from browsers

After hours of googling, reading, uninstalling, facepalming! It turned out that a chrome extension for VPN was handling the proxy settings for Chrome!

Betternet to be more specific!

Disabling it, solved my problem.

To make sure it is not the problem, check the proxy settings for Chrome itself. For me it showed me a message, says : Betternet is handling the proxy settings.

How to turn on front flash light programmatically in Android?

I have implemented this function in my application through fragments using SurfaceView. The link to this stackoverflow question and its answer can be found here

Hope this helps :)

How can I represent an 'Enum' in Python?

So, I agree. Let's not enforce type safety in Python, but I would like to protect myself from silly mistakes. So what do we think about this?

class Animal(object):
    values = ['Horse','Dog','Cat']

    class __metaclass__(type):
        def __getattr__(self, name):
            return self.values.index(name)

It keeps me from value-collision in defining my enums.

>>> Animal.Cat
2

There's another handy advantage: really fast reverse lookups:

def name_of(self, i):
    return self.values[i]

How to load property file from classpath?

If you use the static method and load the properties file from the classpath folder so you can use the below code :

//load a properties file from class path, inside static method
Properties prop = new Properties();
prop.load(Classname.class.getClassLoader().getResourceAsStream("foo.properties"));

How do I automatically set the $DISPLAY variable for my current session?

You'll need to tell your vnc client to export the correct $DISPLAY once you have logged in. How you do that will probably depend on your vnc client.

proper hibernate annotation for byte[]

i fixed My issue by adding the annotation of @Lob which will create the byte[] in oracle as blob , but this annotation will create the field as oid which not work properly , To make byte[] created as bytea i made customer Dialect for postgres as below

Public class PostgreSQLDialectCustom extends PostgreSQL82Dialect {
    public PostgreSQLDialectCustom() {
        System.out.println("Init PostgreSQLDialectCustom");
        registerColumnType( Types.BLOB, "bytea" );

      }

    @Override
    public SqlTypeDescriptor remapSqlTypeDescriptor(SqlTypeDescriptor sqlTypeDescriptor) {
    if (sqlTypeDescriptor.getSqlType() == java.sql.Types.BLOB) {
      return BinaryTypeDescriptor.INSTANCE;
    }
    return super.remapSqlTypeDescriptor(sqlTypeDescriptor);
  }
 }

Also need to override parameter for the Dialect

spring.jpa.properties.hibernate.dialect=com.ntg.common.DBCompatibilityHelper.PostgreSQLDialectCustom

more hint can be found her : https://dzone.com/articles/postgres-and-oracle

Visual Studio 2013 error MS8020 Build tools v140 cannot be found

That's the platform toolset for VS2015. You uninstalled it, therefore it is no longer available.

To change your Platform Toolset:

  1. Right click your project, go to Properties.
  2. Under Configuration Properties, go to General.
  3. Change your Platform Toolset to one of the available ones.

How To Include CSS and jQuery in my WordPress plugin?

Just to append to @pixeline's answer (tried to add a simple comment but the site said I needed 50 reputation).

If you are writing your plugin for the admin section then you should use:

add_action('admin_enqueue_scripts', "add_my_css_and_my_js_files");

The admin_enqueueu_scripts is the correct hook for the admin section, use wp_enqueue_scripts for the front end.

The following classes could not be instantiated: - android.support.v7.widget.Toolbar

I use android studio 2.3.3: - Open styles.xml - Android studio will show a notification on the top right with two options: "open editor" and "Hide notification". - Click "open editor" - Under theme parent dropdown, click show all themes - Select any theme starting with AppCompat... (I used AppComat.DayNight)

NB: If your title bar disappears, you need to extend AppCompatActivity instead of Activity.

All the best!

My C# application is returning 0xE0434352 to Windows Task Scheduler but it is not crashing

I got the same error but I have fixed it by changing the file reading path from "ConfigFile.xml" to AppDomain.CurrentDomain.BaseDirectory.ToString() + "ConfigFile.xml"

In my case, this error due to file path error because task manager starts program from "System32" as initial path but the folder we thought.

ggplot2, change title size

+ theme(plot.title = element_text(size=22))

Here is the full set of things you can change in element_text:

element_text(family = NULL, face = NULL, colour = NULL, size = NULL,
  hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL,
  color = NULL)

How to install mscomct2.ocx file from .cab file (Excel User Form and VBA)

You're correct that this is really painful to hand out to others, but if you have to, this is how you do it.

  1. Just extract the .ocx file from the .cab file (it is similar to a zip)
  2. Copy to the system folder (c:\windows\sysWOW64 for 64 bit systems and c:\windows\system32 for 32 bit)
  3. Use regsvr32 through the command prompt to register the file (e.g. "regsvr32 c:\windows\sysWOW64\mscomct2.ocx")

References

How to insert a blob into a database using sql server management studio

Do you need to do it from mgmt studio? Here's how we do it from cmd line:

"C:\Program Files\Microsoft SQL Server\MSSQL\Binn\TEXTCOPY.exe" /S < Server> /D < DataBase> /T mytable /C mypictureblob /F "C:\picture.png" /W"where RecId=" /I

How to get parameter value for date/time column from empty MaskedTextBox

You're storing the .Text properties of the textboxes directly into the database, this doesn't work. The .Text properties are Strings (i.e. simple text) and not typed as DateTime instances. Do the conversion first, then it will work.

Do this for each date parameter:

Dim bookIssueDate As DateTime = DateTime.ParseExact( txtBookDateIssue.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture ) cmd.Parameters.Add( New OleDbParameter("@Date_Issue", bookIssueDate ) ) 

Note that this code will crash/fail if a user enters an invalid date, e.g. "64/48/9999", I suggest using DateTime.TryParse or DateTime.TryParseExact, but implementing that is an exercise for the reader.

What is AndroidX?

Android provides a couple of different library sets. One is called the Android support Library, and the other is called AndroidX. Selecting "Use android.* artifacts" indicates that we want to use AndroidX.

SQL Server: Null VS Empty String

The conceptual differences between NULL and "empty-string" are real and very important in database design, but often misunderstood and improperly applied - here's a short description of the two:

NULL - means that we do NOT know what the value is, it may exist, but it may not exist, we just don't know.

Empty-String - means we know what the value is and that it is nothing.

Here's a simple example: Suppose you have a table with people's names including separate columns for first_name, middle_name, and last_name. In the scenario where first_name = 'John', last_name = 'Doe', and middle_name IS NULL, it means that we do not know what the middle name is, or if it even exists. Change that scenario such that middle_name = '' (i.e. empty-string), and it now means that we know that there is no middle name.

I once heard a SQL Server instructor promote making every character type column in a database required, and then assigning a DEFAULT VALUE to each of either '' (empty-string), or 'unknown'. In stating this, the instructor demonstrated he did not have a clear understanding of the difference between NULLs and empty-strings. Admittedly, the differences can seem confusing, but for me the above example helps to clarify the difference. Also, it is important to understand the difference when writing SQL code, and properly handle for NULLs as well as empty-strings.

Create an array with same element repeated multiple times

Array.from({length:5}, i => 1) // [1, 1, 1, 1, 1]

or create array with increasing value

Array.from({length:5}, (e, i)=>i) // [0, 1, 2, 3, 4]

How to check if a number is a power of 2

In C, I tested the i && !(i & (i - 1) trick and compared it with __builtin_popcount(i), using gcc on Linux, with the -mpopcnt flag to be sure to use the CPU's POPCNT instruction. My test program counted the # of integers between 0 and 2^31 that were a power of two.

At first I thought that i && !(i & (i - 1) was 10% faster, even though I verified that POPCNT was used in the disassembly where I used__builtin_popcount.

However, I realized that I had included an if statement, and branch prediction was probably doing better on the bit twiddling version. I removed the if and POPCNT ended up faster, as expected.

Results:

Intel(R) Core(TM) i7-4771 CPU max 3.90GHz

Timing (i & !(i & (i - 1))) trick
30

real    0m13.804s
user    0m13.799s
sys     0m0.000s

Timing POPCNT
30

real    0m11.916s
user    0m11.916s
sys     0m0.000s

AMD Ryzen Threadripper 2950X 16-Core Processor max 3.50GHz

Timing (i && !(i & (i - 1))) trick
30

real    0m13.675s
user    0m13.673s
sys 0m0.000s

Timing POPCNT
30

real    0m13.156s
user    0m13.153s
sys 0m0.000s

Note that here the Intel CPU seems slightly slower than AMD with the bit twiddling, but has a much faster POPCNT; the AMD POPCNT doesn't provide as much of a boost.

popcnt_test.c:

#include "stdio.h"

// Count # of integers that are powers of 2 up to 2^31;
int main() {
  int n;
  for (int z = 0; z < 20; z++){
      n = 0;
      for (unsigned long i = 0; i < 1<<30; i++) {
       #ifdef USE_POPCNT
        n += (__builtin_popcount(i)==1); // Was: if (__builtin_popcount(i) == 1) n++;
       #else
        n += (i && !(i & (i - 1)));  // Was: if (i && !(i & (i - 1))) n++;
       #endif
      }
  }

  printf("%d\n", n);
  return 0;
}

Run tests:

gcc popcnt_test.c -O3 -o test.exe
gcc popcnt_test.c -O3 -DUSE_POPCNT -mpopcnt -o test-popcnt.exe

echo "Timing (i && !(i & (i - 1))) trick"
time ./test.exe

echo
echo "Timing POPCNT"
time ./test-opt.exe

VBA Go to last empty row

This does it:

Do
   c = c + 1
Loop While Cells(c, "A").Value <> ""

'prints the last empty row
Debug.Print c

Bootstrap 4 responsive tables won't take up 100% width

That's because the .table-responsive class adds the property display: block to your element which changes it from the previous display: table.

Override this property back to display: table in your own stylesheet

.table-responsive {
    display: table;
}

Note: make sure this style executes after your bootstrap code for it to override.

Sort array by firstname (alphabetically) in Javascript

try

users.sort((a,b)=> (a.firstname>b.firstname)*2-1)

_x000D_
_x000D_
var users = [_x000D_
  { firstname: "Kate", id: 318, /*...*/ },_x000D_
  { firstname: "Anna", id: 319, /*...*/ },_x000D_
  { firstname: "Cristine", id: 317, /*...*/ },_x000D_
]_x000D_
_x000D_
console.log(users.sort((a,b)=> (a.firstname>b.firstname)*2-1) );
_x000D_
_x000D_
_x000D_

undefined reference to WinMain@16 (codeblocks)

Well I know this answer is not an experienced programmer's approach and of an Old It consultant , but it worked for me .

the answer is "TRY TURNING IT ON AND OFF" . restart codeblocks and it works well reminds me of the 2006 comedy show It Crowd .

How to fix "'System.AggregateException' occurred in mscorlib.dll"

As the message says, you have a task which threw an unhandled exception.

Turn on Break on All Exceptions (Debug, Exceptions) and rerun the program.
This will show you the original exception when it was thrown in the first place.


(comment appended): In VS2015 (or above). Select Debug > Options > Debugging > General and unselect the "Enable Just My Code" option.

How does bitshifting work in Java?

These examples cover the three types of shifts applied to both a positive and a negative number:

// Signed left shift on 626348975
00100101010101010101001110101111 is   626348975
01001010101010101010011101011110 is  1252697950 after << 1
10010101010101010100111010111100 is -1789571396 after << 2
00101010101010101001110101111000 is   715824504 after << 3

// Signed left shift on -552270512
11011111000101010000010101010000 is  -552270512
10111110001010100000101010100000 is -1104541024 after << 1
01111100010101000001010101000000 is  2085885248 after << 2
11111000101010000010101010000000 is  -123196800 after << 3


// Signed right shift on 626348975
00100101010101010101001110101111 is   626348975
00010010101010101010100111010111 is   313174487 after >> 1
00001001010101010101010011101011 is   156587243 after >> 2
00000100101010101010101001110101 is    78293621 after >> 3

// Signed right shift on -552270512
11011111000101010000010101010000 is  -552270512
11101111100010101000001010101000 is  -276135256 after >> 1
11110111110001010100000101010100 is  -138067628 after >> 2
11111011111000101010000010101010 is   -69033814 after >> 3


// Unsigned right shift on 626348975
00100101010101010101001110101111 is   626348975
00010010101010101010100111010111 is   313174487 after >>> 1
00001001010101010101010011101011 is   156587243 after >>> 2
00000100101010101010101001110101 is    78293621 after >>> 3

// Unsigned right shift on -552270512
11011111000101010000010101010000 is  -552270512
01101111100010101000001010101000 is  1871348392 after >>> 1
00110111110001010100000101010100 is   935674196 after >>> 2
00011011111000101010000010101010 is   467837098 after >>> 3

CSS3 transitions inside jQuery .css()

Your code can get messy fast when dealing with CSS3 transitions. I would recommend using a plugin such as jQuery Transit that handles the complexity of CSS3 animations/transitions.

Moreover, the plugin uses webkit-transform rather than webkit-transition, which allows for mobile devices to use hardware acceleration in order to give your web apps that native look and feel when the animations occur.

JS Fiddle Live Demo

Javascript:

$("#startTransition").on("click", function()
{

    if( $(".boxOne").is(":visible")) 
    {
        $(".boxOne").transition({ x: '-100%', opacity: 0.1 }, function () { $(".boxOne").hide(); });
        $(".boxTwo").css({ x: '100%' });
        $(".boxTwo").show().transition({ x: '0%', opacity: 1.0 });
        return;        
    }

    $(".boxTwo").transition({ x: '-100%', opacity: 0.1 }, function () { $(".boxTwo").hide(); });
    $(".boxOne").css({ x: '100%' });
    $(".boxOne").show().transition({ x: '0%', opacity: 1.0 });

});

Most of the hard work of getting cross-browser compatibility is done for you as well and it works like a charm on mobile devices.

generate model using user:references vs user_id:integer

how does rails know that user_id is a foreign key referencing user?

Rails itself does not know that user_id is a foreign key referencing user. In the first command rails generate model Micropost user_id:integer it only adds a column user_id however rails does not know the use of the col. You need to manually put the line in the Micropost model

class Micropost < ActiveRecord::Base
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :microposts
end

the keywords belongs_to and has_many determine the relationship between these models and declare user_id as a foreign key to User model.

The later command rails generate model Micropost user:references adds the line belongs_to :user in the Micropost model and hereby declares as a foreign key.

FYI
Declaring the foreign keys using the former method only lets the Rails know about the relationship the models/tables have. The database is unknown about the relationship. Therefore when you generate the EER Diagrams using software like MySql Workbench you find that there is no relationship threads drawn between the models. Like in the following pic enter image description here

However, if you use the later method you find that you migration file looks like:

def change
    create_table :microposts do |t|
      t.references :user, index: true

      t.timestamps null: false
    end
    add_foreign_key :microposts, :users

Now the foreign key is set at the database level. and you can generate proper EER diagrams. enter image description here

Macro to Auto Fill Down to last adjacent cell

This example shows you how to fill column B based on the the volume of data in Column A. Adjust "A1" accordingly to your needs. It will fill in column B based on the formula in B1.

Range("A1").Select
Selection.End(xlDown).Select
ActiveCell.Offset(0, 1).Select
Range(Selection, Selection.End(xlUp)).Select
Selection.FillDown

Getting the actual usedrange

Public Sub FindTrueUsedRange(RowLast As Long, ColLast As Long)
    Application.EnableEvents = False
    Application.ScreenUpdating = False
    RowLast = 0
    ColLast = 0
    ActiveSheet.UsedRange.Select
    Cells(1, 1).Activate
    Selection.End(xlDown).Select
    Selection.End(xlDown).Select
    On Error GoTo -1: On Error GoTo Quit
    Cells.Find(What:="*", LookIn:=xlFormulas, LookAt:=xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Activate
    On Error GoTo -1: On Error GoTo 0
    RowLast = Selection.Row
    Cells(1, 1).Activate
    Selection.End(xlToRight).Select
    Selection.End(xlToRight).Select
    Cells.Find(What:="*", LookIn:=xlFormulas, LookAt:=xlWhole, SearchOrder:=xlByColumns, SearchDirection:=xlPrevious).Activate
    ColLast = Selection.Column
Quit:
    Application.ScreenUpdating = True
    Application.EnableEvents = True
    On Error GoTo -1: On Error GoTo 0
End Sub

LINQ Where with AND OR condition

Linq With Or Condition by using Lambda expression you can do as below

DataTable dtEmp = new DataTable();

dtEmp.Columns.Add("EmpID", typeof(int));
dtEmp.Columns.Add("EmpName", typeof(string));
dtEmp.Columns.Add("Sal", typeof(decimal));
dtEmp.Columns.Add("JoinDate", typeof(DateTime));
dtEmp.Columns.Add("DeptNo", typeof(int));

dtEmp.Rows.Add(1, "Rihan", 10000, new DateTime(2001, 2, 1), 10);
dtEmp.Rows.Add(2, "Shafi", 20000, new DateTime(2000, 3, 1), 10);
dtEmp.Rows.Add(3, "Ajaml", 25000, new DateTime(2010, 6, 1), 10);
dtEmp.Rows.Add(4, "Rasool", 45000, new DateTime(2003, 8, 1), 20);
dtEmp.Rows.Add(5, "Masthan", 22000, new DateTime(2001, 3, 1), 20);


var res2 = dtEmp.AsEnumerable().Where(emp => emp.Field<int>("EmpID")
            == 1 || emp.Field<int>("EmpID") == 2);

foreach (DataRow row in res2)
{
    Label2.Text += "Emplyee ID: " + row[0] + "   &   Emplyee Name: " + row[1] + ",  ";
}

How do you use colspan and rowspan in HTML tables?

If anyone is looking for a rowspan on both the left AND on the right, here is how you can do it:

_x000D_
_x000D_
table { _x000D_
    border-collapse: collapse;_x000D_
}_x000D_
_x000D_
td {_x000D_
    padding: 20px; _x000D_
    border: 1px solid black; _x000D_
    text-align: center;_x000D_
}
_x000D_
<table>_x000D_
    <tbody>_x000D_
    <tr>_x000D_
        <td rowspan="2">LEFT</td>_x000D_
        <td> 1 </td>_x000D_
        <td> 2 </td>_x000D_
        <td> 3 </td>_x000D_
        <td> 4 </td>_x000D_
        <td rowspan="2">RIGHT</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> 5 </td>_x000D_
        <td> 6 </td>_x000D_
        <td> 7 </td>_x000D_
        <td> 8 </td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
    </tr>_x000D_
    </tbody>_x000D_
</table>
_x000D_
_x000D_
_x000D_

Alternatively, if you want to add the LEFT and RIGHT to an existing rowset, you can achieve the same result by throwing them in with a collapsed colspan in between:

_x000D_
_x000D_
table {_x000D_
    border-collapse: collapse;_x000D_
}_x000D_
_x000D_
td {_x000D_
    padding: 20px; _x000D_
    border: 1px solid black; _x000D_
    text-align: center;_x000D_
}
_x000D_
<table>_x000D_
    <tbody>_x000D_
    <tr>_x000D_
        <td rowspan="3">LEFT</td>_x000D_
        <td colspan="4" style="padding: 0; border-bottom: solid 1px transparent;"></td>_x000D_
        <td rowspan="3">RIGHT</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> 1 </td>_x000D_
        <td> 2 </td>_x000D_
        <td> 3 </td>_x000D_
        <td> 4 </td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> 5 </td>_x000D_
        <td> 6 </td>_x000D_
        <td> 7 </td>_x000D_
        <td> 8 </td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
        <td> - </td>_x000D_
    </tr>_x000D_
    </tbody>_x000D_
</table>
_x000D_
_x000D_
_x000D_

How to get the date from jQuery UI datepicker

I just made some web scraping to discover the behaviour of JequeryUI datepicker, it was necessary for me because I'm not familiar with JS object so:

var month = $(".ui-datepicker-current-day").attr("data-month");
var year = $(".ui-datepicker-current-day").attr("data-year");
var day = $(".ui-state-active").text();

it just pick the value in relation of the changing of class, so you can implement the onchange event:

$(document).on('change', '#datepicker', function() { 
    var month = $(".ui-datepicker-current-day").attr("data-month");
    var year = $(".ui-datepicker-current-day").attr("data-year");
    var day= $(".ui-state-active").text();
   $("#chosenday").text( day + " " + month  + " " + year )  ;
                        
});

or check if the current day is selected:

   if( $("a").hasClass("ui-state-active") ){ 
     var month = $(".ui-datepicker-current-day").attr("data-month");
     var year = $(".ui-datepicker-current-day").attr("data-year");
     var day= $(".ui-state-active").text();
     $("#chosenday").text( day + " " + month  + " " + year );
    }

How can I display a tooltip message on hover using jQuery?

Tooltip plugin might be too heavyweight for what you need. Simply set the 'title' attribute with the text you desire to show in your tooltip.

$("#yourElement").attr('title', 'This is the hover-over text');

Calling startActivity() from outside of an Activity?

if your android version is below Android - 6 then you need to add this line otherwise it will work above Android - 6.

...
Intent i = new Intent(this, Wakeup.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
...

How to add to an NSDictionary

For reference, you can also utilize initWithDictionary to init the NSMutableDictionary with a literal one:

NSMutableDictionary buttons = [[NSMutableDictionary alloc] initWithDictionary: @{
    @"touch": @0,
    @"app": @0,
    @"back": @0,
    @"volup": @0,
    @"voldown": @0
}];

I have created a table in hive, I would like to know which directory my table is created in?

All HIVE managed tables are stored in the below HDFS location.

hadoop fs -ls /user/hive/warehouse/databasename.db/tablename

What is the best way to determine a session variable is null or empty in C#?

To follow on from what others have said. I tend to have two layers:

The core layer. This is within a DLL that is added to nearly all web app projects. In this I have a SessionVars class which does the grunt work for Session state getters/setters. It contains code like the following:

public class SessionVar
{
    static HttpSessionState Session
    {
        get
        {
            if (HttpContext.Current == null)
                throw new ApplicationException("No Http Context, No Session to Get!");

            return HttpContext.Current.Session;
        }
    }

    public static T Get<T>(string key)
    {
        if (Session[key] == null)
            return default(T);
        else
            return (T)Session[key];
    }

    public static void Set<T>(string key, T value)
    {
        Session[key] = value;
    }
}

Note the generics for getting any type.

I then also add Getters/Setters for specific types, especially string since I often prefer to work with string.Empty rather than null for variables presented to Users.

e.g:

public static string GetString(string key)
{
    string s = Get<string>(key);
    return s == null ? string.Empty : s;
}

public static void SetString(string key, string value)
{
    Set<string>(key, value);
}

And so on...

I then create wrappers to abstract that away and bring it up to the application model. For example, if we have customer details:

public class CustomerInfo
{
    public string Name
    {
        get
        {
            return SessionVar.GetString("CustomerInfo_Name");
        }
        set
        {
            SessionVar.SetString("CustomerInfo_Name", value);
        }
    }
}

You get the idea right? :)

NOTE: Just had a thought when adding a comment to the accepted answer. Always ensure objects are serializable when storing them in Session when using a state server. It can be all too easy to try and save an object using the generics when on web farm and it go boom. I deploy on a web farm at work so added checks to my code in the core layer to see if the object is serializable, another benefit of encapsulating the Session Getters and Setters :)

How do I check if a string contains a specific word?

You can use the strstr function:

$haystack = "I know programming";
$needle   = "know";
$flag = strstr($haystack, $needle);

if ($flag){

    echo "true";
}

Without using an inbuilt function:

$haystack  = "hello world";
$needle = "llo";

$i = $j = 0;

while (isset($needle[$i])) {
    while (isset($haystack[$j]) && ($needle[$i] != $haystack[$j])) {
        $j++;
        $i = 0;
    }
    if (!isset($haystack[$j])) {
        break;
    }
    $i++;
    $j++;

}
if (!isset($needle[$i])) {
    echo "YES";
}
else{
    echo "NO ";
}

Visual Studio Code: format is not using indent settings

Disable all plugins (then enable one by one and verify)

?: operator (the 'Elvis operator') in PHP

Be careful with arrays. We must write a checking variable after ?, because:

  $params = ['param1' => 'value1',
             'param2' => 'value2',
             'param3' => 'value3',];

  $param1 = isset($params['param1'])?:null;
  $param2 = !empty($params['param2'])?:null;
  $param3 = $params['param3']?:null; // get E_NOTICE, if $params['param3'] eq false

  var_dump($param1,$param2,$param3);
  true // would like to expect `value1`
  true // would like to expect `value2`
  param3 // properly, but problem above

Updated

From RFC. In PHP 7 the operator Null Coalesce Operator will do it, for example:

$param1 = $params['param1'] ?? null;
// Equivalent to:  $param1 = isset($params['param1']) ? $params['param1'] : null;

Passing a variable to a powershell script via command line

Make this in your test.ps1, at the first line

param(
[string]$a
)

Write-Host $a

Then you can call it with

./Test.ps1 "Here is your text"

Found here (English)

Is it possible to use a div as content for Twitter's Popover

Another alternate method if you wish to just have look and feel of pop over. Following is the method. Offcourse this is a manual thing, but nicely workable :)

HTML - button

<button class="btn btn-info btn-small" style="margin-right:5px;" id="bg" data-placement='bottom' rel="tooltip" title="Background Image"><i class="icon-picture icon-white"></i></button>

HTML - popover

<div class="bgform popover fade bottom in">
            <div class="arrow"></div>
             ..... your code here .......
</div>

JS

$("#bg").click(function(){
        $('.bgform').slideToggle();
});

RestSharp JSON Parameter Posting

If you have a List of objects, you can serialize them to JSON as follow:

List<MyObjectClass> listOfObjects = new List<MyObjectClass>();

And then use addParameter:

requestREST.AddParameter("myAssocKey", JsonConvert.SerializeObject(listOfObjects));

And you wil need to set the request format to JSON:

requestREST.RequestFormat = DataFormat.Json;

boto3 client NoRegionError: You must specify a region error only sometimes

For those using CloudFormation template. You can set AWS_DEFAULT_REGION environment variable using UserData and AWS::Region. For example,

MyInstance1:
    Type: AWS::EC2::Instance                
    Properties:                           
        ImageId: ami-04b9e92b5572fa0d1 #ubuntu
        InstanceType: t2.micro
        UserData: 
            Fn::Base64: !Sub |
                    #!/bin/bash -x

                    echo "export AWS_DEFAULT_REGION=${AWS::Region}" >> /etc/profile

What is "string[] args" in Main class for?

The args parameter stores all command line arguments which are given by the user when you run the program.

If you run your program from the console like this:

program.exe there are 4 parameters

Your args parameter will contain the four strings: "there", "are", "4", and "parameters"

Here is an example of how to access the command line arguments from the args parameter: example

WCF ServiceHost access rights

Open Visual Studio as an Administrator.. It will run.

Tensorflow r1.0 : could not a find a version that satisfies the requirement tensorflow

I did it with:

python3 -m pip install --upgrade tensorflow

How to create folder with PHP code?

... You can then use copy() to duplicate a PHP file, although this sounds incredibly inefficient.

jQuery ajax post file field

File uploads can not be done this way, no matter how you break it down. If you want to do an ajax/async upload, I would suggest looking into something like Uploadify, or Valums

Spark - load CSV file as DataFrame?

Parse CSV and load as DataFrame/DataSet with Spark 2.x

First, initialize SparkSession object by default it will available in shells as spark

val spark = org.apache.spark.sql.SparkSession.builder
        .master("local") # Change it as per your cluster
        .appName("Spark CSV Reader")
        .getOrCreate;

Use any one of the following ways to load CSV as DataFrame/DataSet

1. Do it in a programmatic way

 val df = spark.read
         .format("csv")
         .option("header", "true") //first line in file has headers
         .option("mode", "DROPMALFORMED")
         .load("hdfs:///csv/file/dir/file.csv")

Update: Adding all options from here in case the link will be broken in future

  • path: location of files. Similar to Spark can accept standard Hadoop globbing expressions.
  • header: when set to true the first line of files will be used to name columns and will not be included in data. All types will be assumed string. The default value is false.
  • delimiter: by default columns are delimited using, but delimiter can be set to any character
  • quote: by default the quote character is ", but can be set to any character. Delimiters inside quotes are ignored
  • escape: by default, the escape character is , but can be set to any character. Escaped quote characters are ignored
  • parserLib: by default, it is "commons" that can be set to "univocity" to use that library for CSV parsing.
  • mode: determines the parsing mode. By default it is PERMISSIVE. Possible values are:
    • PERMISSIVE: tries to parse all lines: nulls are inserted for missing tokens and extra tokens are ignored.
    • DROPMALFORMED: drops lines which have fewer or more tokens than expected or tokens which do not match the schema
    • FAILFAST: aborts with a RuntimeException if encounters any malformed line charset: defaults to 'UTF-8' but can be set to other valid charset names
  • inferSchema: automatically infers column types. It requires one extra pass over the data and is false by default comment: skip lines beginning with this character. Default is "#". Disable comments by setting this to null.
  • nullValue: specifies a string that indicates a null value, any fields matching this string will be set as nulls in the DataFrame
  • dateFormat: specifies a string that indicates the date format to use when reading dates or timestamps. Custom date formats follow the formats at java.text.SimpleDateFormat. This applies to both DateType and TimestampType. By default, it is null which means trying to parse times and date by java.sql.Timestamp.valueOf() and java.sql.Date.valueOf().

2. You can do this SQL way as well

 val df = spark.sql("SELECT * FROM csv.`hdfs:///csv/file/dir/file.csv`")

Dependencies:

 "org.apache.spark" % "spark-core_2.11" % 2.0.0,
 "org.apache.spark" % "spark-sql_2.11" % 2.0.0,

Spark version < 2.0

val df = sqlContext.read
    .format("com.databricks.spark.csv")
    .option("header", "true") 
    .option("mode", "DROPMALFORMED")
    .load("csv/file/path"); 

Dependencies:

"org.apache.spark" % "spark-sql_2.10" % 1.6.0,
"com.databricks" % "spark-csv_2.10" % 1.6.0,
"com.univocity" % "univocity-parsers" % LATEST,

Excel VBA: function to turn activecell to bold

A UDF will only return a value it won't allow you to change the properties of a cell/sheet/workbook. Move your code to a Worksheet_Change event or similar to change properties.

Eg

Private Sub worksheet_change(ByVal target As Range)
  target.Font.Bold = True
End Sub

Render partial view with dynamic model in Razor view engine and ASP.NET MVC 3

Can also be called as

@Html.Partial("_PartialView", (ModelClass)View.Data)

Error: Uncaught (in promise): Error: Cannot match any routes Angular 2

I am using angular 4 and faced the same issue apply, all possible solution but finally, this solve my problem

export class AppRoutingModule {
constructor(private router: Router) {
    this.router.errorHandler = (error: any) => {
        this.router.navigate(['404']); // or redirect to default route
    }
  }
}

Hope this will help you.

Can I write or modify data on an RFID tag?

I did some development with Mifare Classic (ISO 14443A) cards about 7-8 years ago. You can read and write to all sectors of the card, IIRC the only data you can't change is the serial number. Back then we used a proprietary library from Philips Semiconductors. The command interface to the card was quite alike the ISO 7816-4 (used with standard Smart Cards).

I'd recomment that you look at the OpenPCD platform if you are into development.

This is also of interest regarding the cryptographic functions in some RFID cards.

Apache won't run in xampp

In my case, it was something else. One day earlier I tried to install wordpress using bitnam of xampp, but I was not successfull. When I saw the error log, there was an error :

httpd.exe: Syntax error on line 560 of C:/xampp/apache/conf/httpd.conf: Could not open configuration file C:/xampp/apps/wordpress/conf/httpd-prefix.conf: The system cannot find the path specified.

I opened the httpd.conf and found this line:

Include "C:/xampp/apps/wordpress/conf/httpd-prefix.conf"

I just commented it with #,

Now it's running fine. :)

Convert pandas dataframe to NumPy array

Further to meteore's answer, I found the code

df.index = df.index.astype('i8')

doesn't work for me. So I put my code here for the convenience of others stuck with this issue.

city_cluster_df = pd.read_csv(text_filepath, encoding='utf-8')
# the field 'city_en' is a string, when converted to Numpy array, it will be an object
city_cluster_arr = city_cluster_df[['city_en','lat','lon','cluster','cluster_filtered']].to_records()
descr=city_cluster_arr.dtype.descr
# change the field 'city_en' to string type (the index for 'city_en' here is 1 because before the field is the row index of dataframe)
descr[1]=(descr[1][0], "S20")
newArr=city_cluster_arr.astype(np.dtype(descr))

Curly braces in string in PHP

This is the complex (curly) syntax for string interpolation. From the manual:

Complex (curly) syntax

This isn't called complex because the syntax is complex, but because it allows for the use of complex expressions.

Any scalar variable, array element or object property with a string representation can be included via this syntax. Simply write the expression the same way as it would appear outside the string, and then wrap it in { and }. Since { can not be escaped, this syntax will only be recognised when the $ immediately follows the {. Use {\$ to get a literal {$. Some examples to make it clear:

<?php
// Show all errors
error_reporting(E_ALL);

$great = 'fantastic';

// Won't work, outputs: This is { fantastic}
echo "This is { $great}";

// Works, outputs: This is fantastic
echo "This is {$great}";
echo "This is ${great}";

// Works
echo "This square is {$square->width}00 centimeters broad."; 


// Works, quoted keys only work using the curly brace syntax
echo "This works: {$arr['key']}";


// Works
echo "This works: {$arr[4][3]}";

// This is wrong for the same reason as $foo[bar] is wrong  outside a string.
// In other words, it will still work, but only because PHP first looks for a
// constant named foo; an error of level E_NOTICE (undefined constant) will be
// thrown.
echo "This is wrong: {$arr[foo][3]}"; 

// Works. When using multi-dimensional arrays, always use braces around arrays
// when inside of strings
echo "This works: {$arr['foo'][3]}";

// Works.
echo "This works: " . $arr['foo'][3];

echo "This works too: {$obj->values[3]->name}";

echo "This is the value of the var named $name: {${$name}}";

echo "This is the value of the var named by the return value of getName(): {${getName()}}";

echo "This is the value of the var named by the return value of \$object->getName(): {${$object->getName()}}";

// Won't work, outputs: This is the return value of getName(): {getName()}
echo "This is the return value of getName(): {getName()}";
?>

Often, this syntax is unnecessary. For example, this:

$a = 'abcd';
$out = "$a $a"; // "abcd abcd";

behaves exactly the same as this:

$out = "{$a} {$a}"; // same

So the curly braces are unnecessary. But this:

$out = "$aefgh";

will, depending on your error level, either not work or produce an error because there's no variable named $aefgh, so you need to do:

$out = "${a}efgh"; // or
$out = "{$a}efgh";

Convert a Unicode string to a string in Python (containing extra symbols)

Here is an example:

>>> u = u'€€€'
>>> s = u.encode('utf8')
>>> s
'\xe2\x82\xac\xe2\x82\xac\xe2\x82\xac'

How to check View Source in Mobile Browsers (Both Android && Feature Phone)

This is an old post but still a problem within the Chrome dev tools. I find the best way to check mobile source locally is to open the site locally in Xcode's iOS Simulator. Then from there you open the Safari browser and enable dev tools, if you have not already done this (go to preferences -> advanced -> show develop menu in menu bar). Now you will see the develop option in the main menu and can go to develop -> iOS Simulator -> and the page you have open in Xcode's iOS Simulator will be there. Once you click on it, it will open the web inspector and you can edit as you would normally in the browser dev tools.

I'm afraid this solution will only work on a Mac though as it uses Xcode.

Youtube iframe wmode issue

Just a tip!--make sure you up the z-index on the element you want to be over the embedded video. I added the wmode querystring, and it still didn't work...until I upped the z-index of the other element. :)

How to generate a random string of 20 characters

I'd use this approach:

String randomString(final int length) {
    Random r = new Random(); // perhaps make it a class variable so you don't make a new one every time
    StringBuilder sb = new StringBuilder();
    for(int i = 0; i < length; i++) {
        char c = (char)(r.nextInt((int)(Character.MAX_VALUE)));
        sb.append(c);
    }
    return sb.toString();
}

If you want a byte[] you can do this:

byte[] randomByteString(final int length) {
    Random r = new Random();
    byte[] result = new byte[length];
    for(int i = 0; i < length; i++) {
        result[i] = r.nextByte();
    }
    return result;
}

Or you could do this

byte[] randomByteString(final int length) {
    Random r = new Random();
    StringBuilder sb = new StringBuilder();
    for(int i = 0; i < length; i++) {
        char c = (char)(r.nextInt((int)(Character.MAX_VALUE)));
        sb.append(c);
    }
    return sb.toString().getBytes();
}

Regular expression to extract text between square brackets

(?<=\[).+?(?=\])

Will capture content without brackets

  • (?<=\[) - positive lookbehind for [

  • .*? - non greedy match for the content

  • (?=\]) - positive lookahead for ]

EDIT: for nested brackets the below regex should work:

(\[(?:\[??[^\[]*?\]))

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

getPathInfo() gives the extra path information after the URI, used to access your Servlet, where as getRequestURI() gives the complete URI.

I would have thought they would be different, given a Servlet must be configured with its own URI pattern in the first place; I don't think I've ever served a Servlet from root (/).

For example if Servlet 'Foo' is mapped to URI '/foo' then I would have thought the URI:

/foo/path/to/resource

Would result in:

RequestURI = /foo/path/to/resource

and

PathInfo = /path/to/resource

How to make MySQL handle UTF-8 properly

The charset is a property of the database (default) and the table. You can have a look (MySQL commands):

show create database foo; 
> CREATE DATABASE  `foo`.`foo` /*!40100 DEFAULT CHARACTER SET latin1 */

show create table foo.bar;
> lots of stuff ending with
> ) ENGINE=InnoDB AUTO_INCREMENT=252 DEFAULT CHARSET=latin1

In other words; it's quite easy to check your database charset or change it:

ALTER TABLE `foo`.`bar` CHARACTER SET utf8;

Show/hide widgets in Flutter programmatically

For beginner try this too.

class Visibility extends StatefulWidget {
  @override
  _VisibilityState createState() => _VisibilityState();
}

class _VisibilityState extends State<Visibility> {
  bool a = true;
  String mText = "Press to hide";

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: "Visibility",
      home: new Scaffold(
          body: new Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              new RaisedButton(
                onPressed: _visibilitymethod, child: new Text(mText),),
                a == true ? new Container(
                width: 300.0,
                height: 300.0,
                color: Colors.red,
              ) : new Container(),
            ],
          )
      ),
    );
  }

  void _visibilitymethod() {
    setState(() {
      if (a) {
        a = false;
        mText = "Press to show";
      } else {
        a = true;
        mText = "Press to hide";
      }
    });
  }
}

Show/hide 'div' using JavaScript

I found this question and recently I was implementing some UIs using Vue.js so this can be a good alternative.

First your code is not hiding target when you click on View Profile. You are overriding the content target with div2.

_x000D_
_x000D_
let multiple = new Vue({_x000D_
  el: "#multiple",_x000D_
  data: {_x000D_
    items: [{_x000D_
        id: 0,_x000D_
        name: 'View Profile',_x000D_
        desc: 'Show profile',_x000D_
        show: false,_x000D_
      },_x000D_
      {_x000D_
        id: 1,_x000D_
        name: 'View Results',_x000D_
        desc: 'Show results',_x000D_
        show: false,_x000D_
      },_x000D_
    ],_x000D_
    selected: '',_x000D_
    shown: false,_x000D_
  },_x000D_
  methods: {_x000D_
    showItem: function(item) {_x000D_
      if (this.selected && this.selected.id === item.id) {_x000D_
        item.show = item.show && this.shown ? false : !item.show;_x000D_
      } else {_x000D_
        item.show = (this.selected.show || !item.show) && this.shown ? true : !this.shown;_x000D_
      }_x000D_
      this.shown = item.show;_x000D_
      this.selected = item;_x000D_
    },_x000D_
  },_x000D_
});
_x000D_
<div id="multiple">_x000D_
  <button type="button" v-for="item in items" v-on:click="showItem(item)">{{item.name}}</button>_x000D_
_x000D_
  <div class="" v-if="shown">: {{selected.desc}}</div>_x000D_
</div>_x000D_
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.7/vue.js"></script>
_x000D_
_x000D_
_x000D_

writing to existing workbook using xlwt

openpyxl

# -*- coding: utf-8 -*-
import openpyxl
file = 'sample.xlsx'
wb = openpyxl.load_workbook(filename=file)
# Seleciono la Hoja
ws = wb.get_sheet_by_name('Hoja1')
# Valores a Insertar
ws['A3'] = 42
ws['A4'] = 142
# Escribirmos en el Fichero
wb.save(file)

python ignore certificate validation urllib2

A more explicit example, built on Damien's code (calls a test resource at http://httpbin.org/). For python3. Note that if the server redirects to another URL, uri in add_password has to contain the new root URL (it's possible to pass a list of URLs, also).

import ssl    
import urllib.parse
import urllib.request

def get_resource(uri, user, passwd=False):
    """
    Get the content of the SSL page.
    """
    uri = 'https://httpbin.org/basic-auth/user/passwd'
    user = 'user'
    passwd = 'passwd'

    context = ssl.create_default_context()
    context.check_hostname = False
    context.verify_mode = ssl.CERT_NONE

    password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
    password_mgr.add_password(None, uri, user, passwd)

    auth_handler = urllib.request.HTTPBasicAuthHandler(password_mgr)

    opener = urllib.request.build_opener(auth_handler, urllib.request.HTTPSHandler(context=context))

    urllib.request.install_opener(opener)

    return urllib.request.urlopen(uri).read()

Cluster analysis in R: determine the optimal number of clusters

In order to determine optimal k-cluster in clustering methods. I usually using Elbow method accompany by Parallel processing to avoid time-comsuming. This code can sample like this:

Elbow method

elbow.k <- function(mydata){
dist.obj <- dist(mydata)
hclust.obj <- hclust(dist.obj)
css.obj <- css.hclust(dist.obj,hclust.obj)
elbow.obj <- elbow.batch(css.obj)
k <- elbow.obj$k
return(k)
}

Running Elbow parallel

no_cores <- detectCores()
    cl<-makeCluster(no_cores)
    clusterEvalQ(cl, library(GMD))
    clusterExport(cl, list("data.clustering", "data.convert", "elbow.k", "clustering.kmeans"))
 start.time <- Sys.time()
 elbow.k.handle(data.clustering))
 k.clusters <- parSapply(cl, 1, function(x) elbow.k(data.clustering))
    end.time <- Sys.time()
    cat('Time to find k using Elbow method is',(end.time - start.time),'seconds with k value:', k.clusters)

It works well.

Alter and Assign Object Without Side Effects

If you're using jQuery, you can use extend

myElement.id =0;
myElement.value=1;
myArray[0] = $.extend({}, myElement);

myElement.id = 2;
myElement.value = 3;
myArray[1] = $.extend({}, myElement);

Deleting all records in a database table

BlogPost.find_each(&:destroy)

Define constant variables in C++ header

C++17 inline variables

This awesome C++17 feature allow us to:

  • conveniently use just a single memory address for each constant
  • store it as a constexpr: How to declare constexpr extern?
  • do it in a single line from one header

main.cpp

#include <cassert>

#include "notmain.hpp"

int main() {
    // Both files see the same memory address.
    assert(&notmain_i == notmain_func());
    assert(notmain_i == 42);
}

notmain.hpp

#ifndef NOTMAIN_HPP
#define NOTMAIN_HPP

inline constexpr int notmain_i = 42;

const int* notmain_func();

#endif

notmain.cpp

#include "notmain.hpp"

const int* notmain_func() {
    return &notmain_i;
}

Compile and run:

g++ -c -o notmain.o -std=c++17 -Wall -Wextra -pedantic notmain.cpp
g++ -c -o main.o -std=c++17 -Wall -Wextra -pedantic main.cpp
g++ -o main -std=c++17 -Wall -Wextra -pedantic main.o notmain.o
./main

GitHub upstream.

See also: How do inline variables work?

C++ standard on inline variables

The C++ standard guarantees that the addresses will be the same. C++17 N4659 standard draft 10.1.6 "The inline specifier":

6 An inline function or variable with external linkage shall have the same address in all translation units.

cppreference https://en.cppreference.com/w/cpp/language/inline explains that if static is not given, then it has external linkage.

Inline variable implementation

We can observe how it is implemented with:

nm main.o notmain.o

which contains:

main.o:
                 U _GLOBAL_OFFSET_TABLE_
                 U _Z12notmain_funcv
0000000000000028 r _ZZ4mainE19__PRETTY_FUNCTION__
                 U __assert_fail
0000000000000000 T main
0000000000000000 u notmain_i

notmain.o:
0000000000000000 T _Z12notmain_funcv
0000000000000000 u notmain_i

and man nm says about u:

"u" The symbol is a unique global symbol. This is a GNU extension to the standard set of ELF symbol bindings. For such a symbol the dynamic linker will make sure that in the entire process there is just one symbol with this name and type in use.

so we see that there is a dedicated ELF extension for this.

C++17 standard draft on "global" const implies static

This is the quote for what was mentioned at: https://stackoverflow.com/a/12043198/895245

C++17 n4659 standard draft 6.5 "Program and linkage":

3 A name having namespace scope (6.3.6) has internal linkage if it is the name of

  • (3.1) — a variable, function or function template that is explicitly declared static; or,
  • (3.2) — a non-inline variable of non-volatile const-qualified type that is neither explicitly declared extern nor previously declared to have external linkage; or
  • (3.3) — a data member of an anonymous union.

"namespace" scope is what we colloquially often refer to as "global".

Annex C (informative) Compatibility, C.1.2 Clause 6: "basic concepts" gives the rationale why this was changed from C:

6.5 [also 10.1.7]

Change: A name of file scope that is explicitly declared const, and not explicitly declared extern, has internal linkage, while in C it would have external linkage.

Rationale: Because const objects may be used as values during translation in C++, this feature urges programmers to provide an explicit initializer for each const object. This feature allows the user to put const objects in source files that are included in more than one translation unit.

Effect on original feature: Change to semantics of well-defined feature.

Difficulty of converting: Semantic transformation.

How widely used: Seldom.

See also: Why does const imply internal linkage in C++, when it doesn't in C?

Tested in GCC 7.4.0, Ubuntu 18.04.

nginx 502 bad gateway

When I did sudo /etc/init.d/php-fpm start I got the following error:

Starting php-fpm: [28-Mar-2013 16:18:16] ERROR: [pool www] cannot get uid for user 'apache'

I guess /etc/php-fpm.d/www.conf needs to know the user that the webserver is running as and assumes it's apache when, for nginx, it's actually nginx, and needs to be changed.

add id to dynamically created <div>

Here is an example of what I made to created ID's with my JavaScript.

function abs_demo_DemandeEnvoyee_absence(){

    var iDateInitiale = document.getElementById("abs_t_date_JourInitial_absence").value; /* On récupère la date initiale*/
    var iDateFinale = document.getElementById("abs_t_date_JourFinal_absence").value;     /*On récupère la date finale*/
    var sMotif = document.getElementById("abs_txt_motif_absence").value;                 /*On récupère le motif*/  
    var iCompteurDivNumero = 1;                                                         /*Le compteur est initialisé à 1 parce que la div 1 existe*/
    var TestDivVide = document.getElementById("abs_Autorisation_"+iCompteurDivNumero+"_absence") == undefined; //Boléenne, renvoie false si la div existe déjà
    var NewDivCreation = "";                                                            /*Initialisée en string vide pour concaténation*/
    var NewIdCreation;                                                                  /*Utilisée pour créer l'id d'une div dynamiquement*/
    var NewDivVersHTML;                                                                 /*Utilisée pour insérer la nouvelle div dans le html*/


    while(TestDivVide == false){                                                        /*Tant que la div pointée existe*/
        iCompteurDivNumero++;                                                           /*On incrémente le compteur de 1*/
        TestDivVide = document.getElementById("abs_Autorisation_"+iCompteurDivNumero+"_absence") == undefined; /*Abs_autorisation_1_ est écrite en dur.*/   
    }

    NewIdCreation = "abs_Autorisation_"+iCompteurDivNumero+"_absence"                   /*On crée donc la nouvelle ID de DIV*/

                                                                                        /*On crée la nouvelle DIV avec l'ID précédemment créée*/
    NewDivCreation += "<div class=\"abs_AutorisationsDynamiques_absence\" id=\""+NewIdCreation+"\">Votre demande d'autorisation d'absence du <b>"+iDateInitiale+"</b> au <b>"+iDateFinale+"</b>, pour le motif suivant : <i>\""+sMotif+"\"</i> a bien été <span class=\"abs_CouleurTexteEnvoye_absence\">envoyée</span>.</div>";

    document.getElementById("abs_AffichagePanneauDeControle_absence").innerHTML+=NewDivCreation; /*Et on concatenne la nouvelle div créée*/ 

    document.getElementById("abs_Autorisation_1_absence").style.display = 'none'; /*On cache la première div qui contient le message "vous n'avez pas de demande en attente" */

}

Will provide text translation if asked. :)

404 Not Found The requested URL was not found on this server

Just solved this problem! I know the question is quite old, but I just had this same problem and none of the answers above helped to solve it.

Assuming the actual domain name you want to use is specified in your c:\windows\System32\drivers\etc\hosts and your configurations in apache\conf\httpd.conf and apache\conf\extra\httpd-vhots.conf are right, your problem might be the same as mine:

In Apache's htdocs directory I had a shortcut linking to the actual project I wanted to see in the browser. It turns out, Apache doesn't understand shortcuts. My solution was to create a proper symlink:

In windows, and within the httdocs directory, I ran this command in the terminal:

mklink /d ple <your project directory with index.html> 

This created a proper symlink in the httpdocs directory. After restarting the Apache service and then reloading the page, I was able to see my website up :)

How to execute Ant build in command line

is it still actual?

As I can see you wrote <target depends="build-subprojects,build-project" name="build"/>, then you wrote <target name="build-subprojects"/> (it does nothing). Could it be a reason? Does this <echo message="${ant.project.name}: ${ant.file}"/> print appropriate message? If no then target is not running. Take a look at the next link http://www.sqaforums.com/showflat.php?Number=623277

Converting a string to int in Groovy

Here is the an other way. if you don't like exceptions.

def strnumber = "100"
def intValue = strnumber.isInteger() ?  (strnumber as int) : null

Lining up labels with radio buttons in bootstrap

Key insights for me were: - ensure that label content comes after the input-radio field - I tweaked my css to make everything a little closer

.radio-inline+.radio-inline {
    margin-left: 5px;
}

fe_sendauth: no password supplied

This occurs if the password for the database is not given.

default="postgres://postgres:[email protected]:5432/DBname"

How can I run Tensorboard on a remote server?

This is not a proper answer but a troubleshooter, hopefully helps other less seasoned networkers like me.

In my case (firefox+ubuntu16) the browser was connecting, but showing a blank page (with the tensorboard logo on the tab), and no log activity at all was shown. I still don't know what could be the reason for that (didn't look much into it but if anybody knows please let know!), but I solved it switching to ubuntu's default browser. Here the exact steps, pretty much the same as in @Olivier Moindrot's answer:

  1. On the server, start tensorboard: tensorboard --logdir=. --host=localhost --port=6006
  2. On the client, open the ssh tunnel ssh -p 23 <USER>@<SERVER> -N -f -L localhost:16006:localhost:6006
  3. Open ubuntu's Browser and visit localhost:16006. The tensorboard page should load without much delay.

To check that the SSH tunnel is effectively working, a simple echo server like this python script can help:

  1. Put the script into an <ECHO>.py file in the server and run it with python <ECHO>.py. Now the server will have the echo script listening on 0.0.0.0:5555.
  2. On the client, open the ssh tunnel ssh -p <SSH_PORT> <USER>@<SERVER> -N -f -L localhost:12345:localhost:5555
  3. On the client, in the same terminal used to open the tunnel (step 2.), issuing telnet localhost 12345 will connect to the echo script running in the server. Typing hello and pressing enter should print hello back. If that is the case, your SSH tunnel is working. This was my case, and lead me to the conclusion that the problem involved the browser. Trying to connect from a different terminal caused the terminal to freeze.

As I said, hope it helps!
Cheers,
Andres

AngularJS multiple filter with custom filter function

In view file (HTML or EJS)

<div ng-repeat="item in vm.itemList  | filter: myFilter > </div>

and In Controller

$scope.myFilter = function(item) {
return (item.propertyA === 'value' || item.propertyA === 'value');
}

is there a tool to create SVG paths from an SVG file?

(In reply to the "has the situation improved?" part of the question):

Unfortunately, not really. Illustrator's support for SVG has always been a little shaky, and, having mucked around in Illustrator's internals, I doubt we'll see much improvement as far as Illustrator is concerned.

If you're looking for DOM-style access to an Illustrator document, you might want to check out Hanpuku (Disclosure #1: I'm the author. Disclosure #2: It's research code, meaning there are bugs aplenty, and future support is unlikely).

With Hanpuku, you could do something like:

  1. Select the path of interest in Illustrator
  2. Click the "To D3" button
  3. In the script editor, type:

    selection.attr('d', 'M 0 0 L 20 134 L 233 24 Z');

  4. Click run

  5. If the change is as expected, click "To Illustrator" to apply the changes to the document

Granted, this approach doesn't expose the original path string. If you follow the instructions toward the end of the plugin's welcome page, it's possible to edit the Illustrator document with Chrome's developer tools, but there will be lots of ugly engineering exposed everywhere (the SVG DOM that mirrors the Illustrator document is buried inside an iframe deep in the extension—changing the DOM with Chrome's tools and clicking "To Illustrator" should still work, but you will likely encounter lots of problems).

TL;DR: Illustrator uses an internal model that's pretty different from SVG in a lot of ways, meaning that when you iterate between the two, currently, your only choice is to use the subset of features that both support in the same way.