Programs & Examples On #Zend form element

Zend Framework provides the form class in library to create the form. The form has different elements. This tag is related to form elements provide by zend form class.

How can I inject a property value into a Spring Bean which was configured using annotations?

A possible solutions is to declare a second bean which reads from the same properties file:

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="/WEB-INF/app.properties" />
</bean> 

<util:properties id="appProperties" location="classpath:/WEB-INF/app.properties"/>

The bean named 'appProperties' is of type java.util.Properties and can be dependency injected using the @Resource attruibute shown above.

How can I edit a .jar file?

A jar file is a zip archive. You can extract it using 7zip (a great simple tool to open archives). You can also change its extension to zip and use whatever to unzip the file.

Now you have your class file. There is no easy way to edit class file, because class files are binaries (you won't find source code in there. maybe some strings, but not java code). To edit your class file you can use a tool like classeditor.

You have all the strings your class is using hard-coded in the class file. So if the only thing you would like to change is some strings you can do it without using classeditor.

How to serialize a JObject without the formatting?

Call JObject's ToString(Formatting.None) method.

Alternatively if you pass the object to the JsonConvert.SerializeObject method it will return the JSON without formatting.

Documentation: Write JSON text with JToken.ToString

How can I initialize a String array with length 0 in Java?

Ok I actually found the answer but thought I would 'import' the question into SO anyway

String[] files = new String[0];
or
int[] files = new int[0];

Can you run GUI applications in a Docker container?

Based on Jürgen Weigert's answer, I have some improvement:

docker build -t xeyes - << __EOF__
FROM debian
RUN apt-get update
RUN apt-get install -qqy x11-apps
ENV DISPLAY :0
CMD xeyes
__EOF__
XSOCK=/tmp/.X11-unix
XAUTH_DIR=/tmp/.docker.xauth
XAUTH=$XAUTH_DIR/.xauth
mkdir -p $XAUTH_DIR && touch $XAUTH
xauth nlist $DISPLAY | sed -e 's/^..../ffff/' | xauth -f $XAUTH nmerge -
docker run -ti -v $XSOCK:$XSOCK -v $XAUTH_DIR:$XAUTH_DIR -e XAUTHORITY=$XAUTH xeyes

The only difference is that it creates a directory $XAUTH_DIR which is used to place $XAUTH file and mount $XAUTH_DIR directory instead of $XAUTH file into docker container.

The benefit of this method is that you can write a command in /etc/rc.local which is to create a empty folder named $XAUTH_DIR in /tmp and change its mode to 777.

tr '\n' '\000' < /etc/rc.local | sudo tee /etc/rc.local >/dev/null
sudo sed -i 's|\x00XAUTH_DIR=.*\x00\x00|\x00|' /etc/rc.local >/dev/null
tr '\000' '\n' < /etc/rc.local | sudo tee /etc/rc.local >/dev/null
sudo sed -i 's|^exit 0.*$|XAUTH_DIR=/tmp/.docker.xauth; rm -rf $XAUTH_DIR; install -m 777 -d $XAUTH_DIR\n\nexit 0|' /etc/rc.local

When system restart, before user login, docker will mount the $XAUTH_DIR directory automatically if container's restart policy is "always". After user login, you can write a command in ~/.profile which is to create $XAUTH file, then the container will automatically use this $XAUTH file.

tr '\n' '\000' < ~/.profile | sudo tee ~/.profile >/dev/null
sed -i 's|\x00XAUTH_DIR=.*-\x00|\x00|' ~/.profile
tr '\000' '\n' < ~/.profile | sudo tee ~/.profile >/dev/null
echo "XAUTH_DIR=/tmp/.docker.xauth; XAUTH=\$XAUTH_DIR/.xauth; touch \$XAUTH; xauth nlist \$DISPLAY | sed -e 's/^..../ffff/' | xauth -f \$XAUTH nmerge -" >> ~/.profile

Afterall, the container will automatically get the Xauthority file every time the system restart and user login.

How to select an item from a dropdown list using Selenium WebDriver with java?

WebElement select = driver.findElement(By.id("gender"));
List<WebElement> options = select.findElements(By.tagName("option"));
for (WebElement option : options) {
   if("Germany".equals(option.getText()))
       option.click();   
}

How SQL query result insert in temp table?

In MySQL:

create table temp as select * from original_table

Error importing SQL dump into MySQL: Unknown database / Can't create database

Open the sql file and comment out the line that tries to create the existing database.

Rounded corner for textview in android

Simply using an rounded corner image as the background of that view

And don't forget to have your custom image in drawable folder

android:background="@drawable/my_custom_image"

How to solve Permission denied (publickey) error when using Git?

I was getting the same error. My problem was mixing in sudo.

I couldn't create the directory I was cloning into automatically without prefixing the git clone command with sudo. When I did that, however, my ssh keys where not being properly referenced.

To fix it, I set permissions via chmod on the parent directory I wanted to contain my clone so I could write to it. Then I ran git clone WITHOUT a sudo prefix. It then worked! I changed the permissions back after that. Done.

curl_init() function not working

I got it working in ubuntu 16.04 by following steps.My php version was 7.0

sudo apt-get install php7.0-curl

sudo service apache2 restart

i got it from this link check here for more details

How to find all occurrences of an element in a list

Using a for-loop:

  • Answers with enumerate and a list comprehension are more pythonic, not necessarily faster, however, this answer is aimed at students who may not be allowed to use some of those built-in functions.
  • create an empty list, indices
  • create the loop with for i in range(len(x)):, which essentially iterates through a list of index locations [0, 1, 2, 3, ..., len(x)-1]
  • in the loop, add any i, where x[i] is a match to value, to indices
def get_indices(x: list, value: int) -> list:
    indices = list()
    for i in range(len(x)):
        if x[i] == value:
            indices.append(i)
    return indices

n = [1, 2, 3, -50, -60, 0, 6, 9, -60, -60]
print(get_indices(n, -60))

>>> [4, 8, 9]
  • The functions, get_indices, are implemented with type hints. In this case, the list, n, is a bunch of ints, therefore we search for value, also defined as an int.

Using a while-loop and .index:

  • With .index, use try-except for error handling, because a ValueError will occur if value is not in the list.
def get_indices(x: list, value: int) -> list:
    indices = list()
    i = 0
    while True:
        try:
            # find an occurrence of value and update i to that index
            i = x.index(value, i)
            # add i to the list
            indices.append(i)
            # advance i by 1
            i += 1
        except ValueError as e:
            break
    return indices

print(get_indices(n, -60))
>>> [4, 8, 9]

How to create a cron job using Bash automatically without the interactive editor?

Bash script for adding cron job without the interactive editor. Below code helps to add a cronjob using linux files.

#!/bin/bash

cron_path=/var/spool/cron/crontabs/root

#cron job to run every 10 min.
echo "*/10 * * * * command to be executed" >> $cron_path

#cron job to run every 1 hour.
echo "0 */1 * * * command to be executed" >> $cron_path

How can I dynamically set the position of view in Android?

For support to all API levels you can use it like this:

ViewPropertyAnimator.animate(view).translationYBy(-yourY).translationXBy(-yourX).setDuration(0);

Read specific columns from a csv file with csv module?

Thanks to the way you can index and subset a pandas dataframe, a very easy way to extract a single column from a csv file into a variable is:

myVar = pd.read_csv('YourPath', sep = ",")['ColumnName']

A few things to consider:

The snippet above will produce a pandas Series and not dataframe. The suggestion from ayhan with usecols will also be faster if speed is an issue. Testing the two different approaches using %timeit on a 2122 KB sized csv file yields 22.8 ms for the usecols approach and 53 ms for my suggested approach.

And don't forget import pandas as pd

In c++ what does a tilde "~" before a function name signify?

It's the destructor, it destroys the instance, frees up memory, etc. etc.

Here's a description from ibm.com:

Destructors are usually used to deallocate memory and do other cleanup for a class object and its class members when the object is destroyed. A destructor is called for a class object when that object passes out of scope or is explicitly deleted.

See https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_74/rzarg/cplr380.htm

jquery clear input default value

Try that:

  var defaultEmailNews = "Email address";
  $('input[name=email]').focus(function() {
    if($(this).val() == defaultEmailNews) $(this).val("");
  });

  $('input[name=email]').focusout(function() {
    if($(this).val() == "") $(this).val(defaultEmailNews);
  });

How to get the unique ID of an object which overrides hashCode()?

System.identityHashCode(yourObject) will give the 'original' hash code of yourObject as an integer. Uniqueness isn't necessarily guaranteed. The Sun JVM implementation will give you a value which is related to the original memory address for this object, but that's an implementation detail and you shouldn't rely on it.

EDIT: Answer modified following Tom's comment below re. memory addresses and moving objects.

Convert seconds into days, hours, minutes and seconds

Interval class I have written can be used. It can be used in opposite way too.

composer require lubos/cakephp-interval

$Interval = new \Interval\Interval\Interval();

// output 2w 6h
echo $Interval->toHuman((2 * 5 * 8 + 6) * 3600);

// output 36000
echo $Interval->toSeconds('1d 2h');

More info here https://github.com/LubosRemplik/CakePHP-Interval

How to run a Python script in the background even after I logout SSH?

You might consider turning your python script into a proper python daemon, as described here.

python-daemon is a good tool that can be used to run python scripts as a background daemon process rather than a forever running script. You will need to modify existing code a bit but its plain and simple.

If you are facing problems with python-daemon, there is another utility supervisor that will do the same for you, but in this case you wont have to write any code (or modify existing) as this is a out of the box solution for daemonizing processes.

How can I stop Chrome from going into debug mode?

For anyone that's searching why their chrome debugger is automatically jumping to sources tab on every page load, event though all of the breakpoints/pauses/etc have been disabled.

For me it was the "breakOnLoad": true line in VS Code launch.json config.

(change) vs (ngModelChange) in angular

1 - (change) is bound to the HTML onchange event. The documentation about HTML onchange says the following :

Execute a JavaScript when a user changes the selected option of a <select> element

Source : https://www.w3schools.com/jsref/event_onchange.asp

2 - As stated before, (ngModelChange) is bound to the model variable binded to your input.

So, my interpretation is :

  • (change) triggers when the user changes the input
  • (ngModelChange) triggers when the model changes, whether it's consecutive to a user action or not

How can I find out if I have Xcode commandline tools installed?

if you want to know the install version of Xcode as well as Swift language current version:

Use below simple command by using Terminal:

1. To get install Xcode Version

 xcodebuild -version

2. To get install Swift language Version

swift --version

java.lang.NoClassDefFoundError: org/json/JSONObject

Please add the following dependency http://mvnrepository.com/artifact/org.json/json/20080701

<dependency>
   <groupId>org.json</groupId>
   <artifactId>json</artifactId>
   <version>20080701</version>
</dependency>

Watermark / hint text / placeholder TextBox

My solution is quite simple.

In my login window. the xaml is like this.

 <DockPanel HorizontalAlignment="Center" VerticalAlignment="Center" Height="80" Width="300" LastChildFill="True">
        <Button Margin="5,0,0,0" Click="login_Click" DockPanel.Dock="Right"  VerticalAlignment="Center" ToolTip="Login to system">
            Login
        </Button>
        <StackPanel>
            <TextBox x:Name="userNameWatermarked" Height="25" Foreground="Gray" Text="UserName" GotFocus="userNameWatermarked_GotFocus"></TextBox>
            <TextBox x:Name="userName" Height="25"  TextChanged="loginElement_TextChanged" Visibility="Collapsed" LostFocus="userName_LostFocus" ></TextBox>
            <TextBox x:Name="passwordWatermarked" Height="25" Foreground="Gray" Text="Password"  Margin="0,5,0,5" GotFocus="passwordWatermarked_GotFocus"></TextBox>
            <PasswordBox x:Name="password" Height="25" PasswordChanged="password_PasswordChanged" KeyUp="password_KeyUp" LostFocus="password_LostFocus" Margin="0,5,0,5" Visibility="Collapsed"></PasswordBox>
            <TextBlock x:Name="loginError" Visibility="Hidden" Foreground="Red" FontSize="12"></TextBlock>
        </StackPanel>
    </DockPanel>

the code is like this.

private void userNameWatermarked_GotFocus(object sender, RoutedEventArgs e)
    {
        userNameWatermarked.Visibility = System.Windows.Visibility.Collapsed;
        userName.Visibility = System.Windows.Visibility.Visible;
        userName.Focus();
    }

    private void userName_LostFocus(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(this.userName.Text))
        {
            userName.Visibility = System.Windows.Visibility.Collapsed;
            userNameWatermarked.Visibility = System.Windows.Visibility.Visible;
        }
    }

    private void passwordWatermarked_GotFocus(object sender, RoutedEventArgs e)
    {
        passwordWatermarked.Visibility = System.Windows.Visibility.Collapsed;
        password.Visibility = System.Windows.Visibility.Visible;
        password.Focus();
    }

    private void password_LostFocus(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(this.password.Password))
        {
            password.Visibility = System.Windows.Visibility.Collapsed;
            passwordWatermarked.Visibility = System.Windows.Visibility.Visible;
        }
    }

Just decide to hide or show the watermark textbox is enough. Though not beautiful,but work well.

How do you determine the size of a file in C?

Based on NilObject's code:

#include <sys/stat.h>
#include <sys/types.h>

off_t fsize(const char *filename) {
    struct stat st; 

    if (stat(filename, &st) == 0)
        return st.st_size;

    return -1; 
}

Changes:

  • Made the filename argument a const char.
  • Corrected the struct stat definition, which was missing the variable name.
  • Returns -1 on error instead of 0, which would be ambiguous for an empty file. off_t is a signed type so this is possible.

If you want fsize() to print a message on error, you can use this:

#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>

off_t fsize(const char *filename) {
    struct stat st;

    if (stat(filename, &st) == 0)
        return st.st_size;

    fprintf(stderr, "Cannot determine size of %s: %s\n",
            filename, strerror(errno));

    return -1;
}

On 32-bit systems you should compile this with the option -D_FILE_OFFSET_BITS=64, otherwise off_t will only hold values up to 2 GB. See the "Using LFS" section of Large File Support in Linux for details.

How do I hide the status bar in a Swift iOS app?

I actually figured this out myself. I'll add my solution as another option.

extension UIViewController {
    func prefersStatusBarHidden() -> Bool {
        return true
    }
}

How can I find non-ASCII characters in MySQL?

@zende's answer was the only one that covered columns with a mix of ascii and non ascii characters, but it also had that problematic hex thing. I used this:

SELECT * FROM `table` WHERE NOT `column` REGEXP '^[ -~]+$' AND `column` !=''

python: after installing anaconda, how to import pandas

I know there are a lot of answers to this already but I would like to put in my two cents. When creating a virtual environment in anaconda launcher you still need to install the packages you need. This is deceiving because I assumed since I was using anaconda that packages such as pandas, numpy etc would be include. This is not the case. It gives you a fresh environment with none of those packages installed, at least mine did. All my packages installed into the environment with no problem and work correctly.

Bulk load data conversion error (type mismatch or invalid character for the specified codepage) for row 1, column 4 (Year)

Try using a format file since your data file only has 4 columns. Otherwise, try OPENROWSET or use a staging table.

myTestFormatFiles.Fmt may look like:

9.0
4
1       SQLINT        0       3       ","      1     StudentNo      ""
2       SQLCHAR       0       100     ","      2     FirstName      SQL_Latin1_General_CP1_CI_AS
3       SQLCHAR       0       100     ","      3     LastName       SQL_Latin1_General_CP1_CI_AS
4       SQLINT        0       4       "\r\n"   4     Year           "


(source: microsoft.com)

This tutorial on skipping a column with BULK INSERT may also help.

Your statement then would look like:

USE xta9354
GO
BULK INSERT xta9354.dbo.Students
    FROM 'd:\userdata\xta9_Students.txt' 
    WITH (FORMATFILE = 'C:\myTestFormatFiles.Fmt')

Meaning of numbers in "col-md-4"," col-xs-1", "col-lg-2" in Bootstrap

From Twitter Bootstrap documentation:

  • small grid (= 768px) = .col-sm-*,
  • medium grid (= 992px) = .col-md-*,
  • large grid (= 1200px) = .col-lg-*.

to Read More...

How to make a text box have rounded corners?

This can be done with CSS3:

<input type="text" />

input
{
  -moz-border-radius: 15px;
 border-radius: 15px;
    border:solid 1px black;
    padding:5px;
}

http://jsfiddle.net/UbSkn/1/


However, an alternative would be to put the input inside a div with a rounded background, and no border on the input

SpringApplication.run main method

One more way is to extend the application (as my application was to inherit and customize the parent). It invokes the parent and its commandlinerunner automatically.

@SpringBootApplication
public class ChildApplication extends ParentApplication{
    public static void main(String[] args) {
        SpringApplication.run(ChildApplication.class, args);
    }
}

How to emulate GPS location in the Android Emulator?

You can use an emulator like genymotion which gives you the flexibility to emulate your present GPS location, etc.

Iterator invalidation rules

C++17 (All references are from the final working draft of CPP17 - n4659)


Insertion

Sequence Containers

  • vector: The functions insert, emplace_back, emplace, push_back cause reallocation if the new size is greater than the old capacity. Reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. If no reallocation happens, all the iterators and references before the insertion point remain valid. [26.3.11.5/1]
    With respect to the reserve function, reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. No reallocation shall take place during insertions that happen after a call to reserve() until the time when an insertion would make the size of the vector greater than the value of capacity(). [26.3.11.3/6]

  • deque: An insertion in the middle of the deque invalidates all the iterators and references to elements of the deque. An insertion at either end of the deque invalidates all the iterators to the deque, but has no effect on the validity of references to elements of the deque. [26.3.8.4/1]

  • list: Does not affect the validity of iterators and references. If an exception is thrown there are no effects. [26.3.10.4/1].
    The insert, emplace_front, emplace_back, emplace, push_front, push_back functions are covered under this rule.

  • forward_list: None of the overloads of insert_after shall affect the validity of iterators and references [26.3.9.5/1]

  • array: As a rule, iterators to an array are never invalidated throughout the lifetime of the array. One should take note, however, that during swap, the iterator will continue to point to the same array element, and will thus change its value.

Associative Containers

  • All Associative Containers: The insert and emplace members shall not affect the validity of iterators and references to the container [26.2.6/9]

Unordered Associative Containers

  • All Unordered Associative Containers: Rehashing invalidates iterators, changes ordering between elements, and changes which buckets elements appear in, but does not invalidate pointers or references to elements. [26.2.7/9]
    The insert and emplace members shall not affect the validity of references to container elements, but may invalidate all iterators to the container. [26.2.7/14]
    The insert and emplace members shall not affect the validity of iterators if (N+n) <= z * B, where N is the number of elements in the container prior to the insert operation, n is the number of elements inserted, B is the container’s bucket count, and z is the container’s maximum load factor. [26.2.7/15]

  • All Unordered Associative Containers: In case of a merge operation (e.g., a.merge(a2)), iterators referring to the transferred elements and all iterators referring to a will be invalidated, but iterators to elements remaining in a2 will remain valid. (Table 91 — Unordered associative container requirements)

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

Erasure

Sequence Containers

  • vector: The functions erase and pop_back invalidate iterators and references at or after the point of the erase. [26.3.11.5/3]

  • deque: An erase operation that erases the last element of a deque invalidates only the past-the-end iterator and all iterators and references to the erased elements. An erase operation that erases the first element of a deque but not the last element invalidates only iterators and references to the erased elements. An erase operation that erases neither the first element nor the last element of a deque invalidates the past-the-end iterator and all iterators and references to all the elements of the deque. [ Note: pop_front and pop_back are erase operations. —end note ] [26.3.8.4/4]

  • list: Invalidates only the iterators and references to the erased elements. [26.3.10.4/3]. This applies to erase, pop_front, pop_back, clear functions.
    remove and remove_if member functions: Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value, pred(*i) != false. Invalidates only the iterators and references to the erased elements [26.3.10.5/15].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version of unique with no arguments) or pred(*i, *(i - 1)) (for the version of unique with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. [26.3.10.5/19]

  • forward_list: erase_after shall invalidate only iterators and references to the erased elements. [26.3.9.5/1].
    remove and remove_if member functions - Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value (for remove()), pred(*i) is true (for remove_if()). Invalidates only the iterators and references to the erased elements. [26.3.9.6/12].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version with no arguments) or pred(*i, *(i - 1)) (for the version with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. [26.3.9.6/16]

  • All Sequence Containers: clear invalidates all references, pointers, and iterators referring to the elements of a and may invalidate the past-the-end iterator (Table 87 — Sequence container requirements). But for forward_list, clear does not invalidate past-the-end iterators. [26.3.9.5/32]

  • All Sequence Containers: assign invalidates all references, pointers and iterators referring to the elements of the container. For vector and deque, also invalidates the past-the-end iterator. (Table 87 — Sequence container requirements)

Associative Containers

  • All Associative Containers: The erase members shall invalidate only iterators and references to the erased elements [26.2.6/9]

  • All Associative Containers: The extract members invalidate only iterators to the removed element; pointers and references to the removed element remain valid [26.2.6/10]

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

General container requirements relating to iterator invalidation:

  • Unless otherwise specified (either explicitly or by defining a function in terms of other functions), invoking a container member function or passing a container as an argument to a library function shall not invalidate iterators to, or change the values of, objects within that container. [26.2.1/12]

  • no swap() function invalidates any references, pointers, or iterators referring to the elements of the containers being swapped. [ Note: The end() iterator does not refer to any element, so it may be invalidated. —end note ] [26.2.1/(11.6)]

As examples of the above requirements:

  • transform algorithm: The op and binary_op functions shall not invalidate iterators or subranges, or modify elements in the ranges [28.6.4/1]

  • accumulate algorithm: In the range [first, last], binary_op shall neither modify elements nor invalidate iterators or subranges [29.8.2/1]

  • reduce algorithm: binary_op shall neither invalidate iterators or subranges, nor modify elements in the range [first, last]. [29.8.3/5]

and so on...

jQuery 'each' loop with JSON array

This works for me:

$.get("data.php", function(data){
    var expected = ['justIn', 'recent', 'old'];
    var outString = '';
    $.each(expected, function(i, val){
        var contentArray = data[val];
        outString += '<ul><li><b>' + val + '</b>: ';
        $.each(contentArray, function(i1, val2){
            var textID = val2.textId;
            var text = val2.text;
            var textType = val2.textType;
            outString += '<br />('+textID+') '+'<i>'+text+'</i> '+textType;
        });
        outString += '</li></ul>';
    });
    $('#contentHere').append(outString);
}, 'json');

This produces this output:

<div id="contentHere"><ul>
<li><b>justIn</b>:
<br />
(123) <i>Hello</i> Greeting<br>
(514) <i>What's up?</i> Question<br>
(122) <i>Come over here</i> Order</li>
</ul><ul>
<li><b>recent</b>:
<br />
(1255) <i>Hello</i> Greeting<br>
(6564) <i>What's up?</i> Question<br>
(0192) <i>Come over here</i> Order</li>
</ul><ul>
<li><b>old</b>:
<br />
(5213) <i>Hello</i> Greeting<br>
(9758) <i>What's up?</i> Question<br>
(7655) <i>Come over here</i> Order</li>
</ul></div>

And looks like this:

  • justIn:
    (123) Hello Greeting
    (514) What's up? Question
    (122) Come over here Order
  • recent:
    (1255) Hello Greeting
    (6564) What's up? Question
    (0192) Come over here Order
  • old:
    (5213) Hello Greeting
    (9758) What's up? Question
    (7655) Come over here Order

Also, remember to set the contentType as 'json'

Can't bind to 'dataSource' since it isn't a known property of 'table'

Remember to import the MatTableModule module and remove the table element show below for reference.
wrong implementation
<table mat-table [dataSource]=”myDataArray”> ... </table>
correct implementation:
<mat-table [dataSource]="myDataArray"> </mat-table>

Hibernate: hbm2ddl.auto=update in production?

I wouldn't risk it because you might end up losing data that should have been preserved. hbm2ddl.auto=update is purely an easy way to keep your dev database up to date.

Finding height in Binary Search Tree

int height(Node* root) {
        if(root==NULL) return -1;
        return max(height(root->left),height(root->right))+1;
}

Take of maximum height from left and right subtree and add 1 to it.This also handles the base case(height of Tree with 1 node is 0).

RegEx: How can I match all numbers greater than 49?

I know this is old, but none of these expressions worked for me (maybe it's because I'm on PHP). The following expression worked fine to validate that a number is higher than 49:

/([5-9][0-9])|([1-9]\d{3}\d*)/

Spring Boot and multiple external configuration files

spring boot allows us to write different profiles to write for different environments, for example we can have separate properties files for production, qa and local environments

application-local.properties file with configurations according to my local machine is

spring.profiles.active=local

spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.database=users
spring.data.mongodb.username=humble_freak
spring.data.mongodb.password=freakone

spring.rabbitmq.host=localhost
spring.rabbitmq.username=guest
spring.rabbitmq.password=guest
spring.rabbitmq.port=5672

rabbitmq.publish=true

Similarly, we can write application-prod.properties and application-qa.properties as many properties files as we want

then write some scripts to start the application for different environments, for e.g.

mvn spring-boot:run -Drun.profiles=local
mvn spring-boot:run -Drun.profiles=qa
mvn spring-boot:run -Drun.profiles=prod

Where is database .bak file saved from SQL Server Management Studio?

As said by Faiyaz, to get default backup location for the instance, you cannot get it into msdb, but you have to look into Registry. You can get it in T-SQL in using xp_instance_regread stored procedure like this:

EXEC  master.dbo.xp_instance_regread 
      N'HKEY_LOCAL_MACHINE', N'SOFTWARE\Microsoft\\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQLServer',N'BackupDirectory'

The double backslash (\\) is because the spaces into that key name part (Microsoft SQL Server). The "MSSQL12.MSSQLSERVER" part is for default instance name for SQL 2014. You have to adapt to put your own instance name (look into Registry).

vertical-align: middle with Bootstrap 2

If I remember correctly from my own use of bootstrap, the .spanN classes are floated, which automatically makes them behave as display: block. To make display: table-cell work, you need to remove the float.

how do I initialize a float to its max/min value?

There's no real need to initialize to smallest/largest possible to find the smallest/largest in the array:

double largest = smallest = array[0];
for (int i=1; i<array_size; i++) {
    if (array[i] < smallest)
        smallest = array[i];
    if (array[i] > largest0
        largest= array[i];
}

Or, if you're doing it more than once:

#include <utility>

template <class iter>
std::pair<typename iter::value_type, typename iter::value_type> find_extrema(iter begin, iter end) {
    std::pair<typename iter::value_type, typename iter::value_type> ret;
    ret.first = ret.second = *begin;
    while (++begin != end) {
        if (*begin < ret.first)
           ret.first = *begin;
        if (*begin > ret.second)
           ret.second = *begin;
   }
   return ret;
}

The disadvantage of providing sample code -- I see others have already suggested the same idea.

Note that while the standard has a min_element and max_element, using these would require scanning through the data twice, which could be a problem if the array is large at all. Recent standards have addressed this by adding a std::minmax_element, which does the same as the find_extrema above (find both the minimum and maximum elements in a collection in a single pass).

Edit: Addressing the problem of finding the smallest non-zero value in an array of unsigned: observe that unsigned values "wrap around" when they reach an extreme. To find the smallest non-zero value, we can subtract one from each for the comparison. Any zero values will "wrap around" to the largest possible value for the type, but the relationship between other values will be retained. After we're done, we obviously add one back to the value we found.

unsigned int min_nonzero(std::vector<unsigned int> const &values) { 
    if (vector.size() == 0)
        return 0;
    unsigned int temp = values[0]-1;
    for (int i=1; i<values.size(); i++)
        if (values[i]-1 < temp)
            temp = values[i]-1;
    return temp+1;
}

Note this still uses the first element for the initial value, but we still don't need any "special case" code -- since that will wrap around to the largest possible value, any non-zero value will compare as being smaller. The result will be the smallest nonzero value, or 0 if and only if the vector contained no non-zero values.

ng serve not detecting file changes automatically

Restarting the server worked for me.

Test for multiple cases in a switch, like an OR (||)

You can use fall-through:

switch (pageid)
{
    case "listing-page":
    case "home-page":
        alert("hello");
        break;
    case "details-page":
        alert("goodbye");
        break;
}

Get PHP class property by string

There might be answers to this question, but you may want to see these migrations to PHP 7

backward incompatible change

source: php.net

postgresql port confusion 5433 or 5432?

/etc/services is only advisory, it's a listing of well-known ports. It doesn't mean that anything is actually running on that port or that the named service will run on that port.

In PostgreSQL's case it's typical to use port 5432 if it is available. If it isn't, most installers will choose the next free port, usually 5433.

You can see what is actually running using the netstat tool (available on OS X, Windows, and Linux, with command line syntax varying across all three).

This is further complicated on Mac OS X systems by the horrible mess of different PostgreSQL packages - Apple's ancient version of PostgreSQL built in to the OS, Postgres.app, Homebrew, Macports, the EnterpriseDB installer, etc etc.

What ends up happening is that the user installs Pg and starts a server from one packaging, but uses the psql and libpq client from a different packaging. Typically this occurs when they're running Postgres.app or homebrew Pg and connecting with the psql that shipped with the OS. Not only do these sometimes have different default ports, but the Pg that shipped with Mac OS X has a different default unix socket path, so even if the server is running on the same port it won't be listening to the same unix socket.

Most Mac users work around this by just using tcp/ip with psql -h localhost. You can also specify a port if required, eg psql -h localhost -p 5433. You might have multiple PostgreSQL instances running so make sure you're connecting to the right one by using select version() and SHOW data_directory;.

You can also specify a unix socket directory; check the unix_socket_directories setting of the PostgreSQL instance you wish to connect to and specify that with psql -h, e.g.psql -h /tmp.

A cleaner solution is to correct your system PATH so that the psql and libpq associated with the PostgreSQL you are actually running is what's found first on the PATH. The details of that depend on your Mac OS X version and which Pg packages you have installed. I don't use Mac and can't offer much more detail on that side without spending more time than is currently available.

CSS Box Shadow - Top and Bottom Only

So this is my first answer here, and because I needed something similar I did with pseudo elements for 2 inner shadows, and an extra DIV for an upper outer shadow. Don't know if this is the best solutions but maybe it will help someone.

HTML

<div class="shadow-block">
    <div class="shadow"></div>
    <div class="overlay">
        <div class="overlay-inner">
            content here
        </div>
    </div>
</div>

CSS

.overlay {
    background: #f7f7f4;
    height: 185px;
    overflow: hidden;
    position: relative;
    width: 100%; 
}

.overlay:before {
    border-radius: 50% 50% 50% 50%;
    box-shadow: 0 0 50px 2px rgba(1, 1, 1, 0.6);
    content: " ";
    display: block;
    margin: 0 auto;
    width: 80%;
}

.overlay:after {
    border-radius: 50% 50% 50% 50%;
    box-shadow: 0 0 70px 5px rgba(1, 1, 1, 0.5);
    content: "-";
    display: block;
    margin: 0 auto;
    position: absolute;
    bottom: -65px;
    left: -50%;
    right: -50%;
    width: 80%;
}

.shadow {
    position: relative;
    width:100%;
    height:8px;
    margin: 0 0 -22px 0;
    -webkit-box-shadow: 0px 0px 50px 3px rgba(1, 1, 1, 0.6);
    box-shadow: 0px 0px 50px 3px rgba(1, 1, 1, 0.6);
    border-radius: 50%;
}

Video auto play is not working in Safari and Chrome desktop browser

Try this:

  <video width="320" height="240"  autoplay muted>
            <source src="video.mp4" type="video/mp4">
  </video>

Read text file into string. C++ ifstream

getline(fin, buffer, '\n')
where fin is opened file(ifstream object) and buffer is of string/char type where you want to copy line.

Unknown URL content://downloads/my_downloads

The exception is caused by disabled Download Manager. And there is no way to activate/deactivate Download Manager directly, since it's system application and we don't have access to it.

Only alternative way is redirect user to settings of Download Manager Application.

try {
     //Open the specific App Info page:
     Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
     intent.setData(Uri.parse("package:" + "com.android.providers.downloads"));
     startActivity(intent);

} catch ( ActivityNotFoundException e ) {
     e.printStackTrace();

     //Open the generic Apps page:
     Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_APPLICATIONS_SETTINGS);
     startActivity(intent);
}

How to extract the decimal part from a floating point number in C?

I made this function, it seems to work fine:

#include <math.h>

void GetFloattoInt (double fnum, long precision, long *pe, long *pd)
{
  long pe_sign;
  long intpart;
  float decpart;

  if(fnum>=0)
  {
    pe_sign=1;
  }
  else
  {
    pe_sign=-1;
  }

  intpart=(long)fnum;
  decpart=fnum-intpart;

  *pe=intpart;  
  *pd=(((long)(decpart*pe_sign*pow(10,precision)))%(long)pow(10,precision));
}

Remove last character of a StringBuilder?

With Java-8 you can use static method of String class,

String#join(CharSequence delimiter,Iterable<? extends CharSequence> elements).


public class Test {

    public static void main(String[] args) {

        List<String> names = new ArrayList<>();
        names.add("James");
        names.add("Harry");
        names.add("Roy");
        System.out.println(String.join(",", names));
    }
}

OUTPUT

James,Harry,Roy

How can I switch my git repository to a particular commit

All the above commands create a new branch and with the latest commit being the one specified in the command, but just in case you want your current branch HEAD to move to the specified commit, below is the command:

 git checkout <commit_hash>

It detaches and point the HEAD to specified commit and saves from creating a new branch when the user just wants to view the branch state till that particular commit.


You then might want to go back to the latest commit & fix the detached HEAD:

Fix a Git detached head?

Background images: how to fill whole div if image is small and vice versa

This worked perfectly for me

background-repeat: no-repeat;
background-size: 100% 100%;

Returning IEnumerable<T> vs. IQueryable<T>

In general you want to preserve the original static type of the query until it matters.

For this reason, you can define your variable as 'var' instead of either IQueryable<> or IEnumerable<> and you will know that you are not changing the type.

If you start out with an IQueryable<>, you typically want to keep it as an IQueryable<> until there is some compelling reason to change it. The reason for this is that you want to give the query processor as much information as possible. For example, if you're only going to use 10 results (you've called Take(10)) then you want SQL Server to know about that so that it can optimize its query plans and send you only the data you'll use.

A compelling reason to change the type from IQueryable<> to IEnumerable<> might be that you are calling some extension function that the implementation of IQueryable<> in your particular object either cannot handle or handles inefficiently. In that case, you might wish to convert the type to IEnumerable<> (by assigning to a variable of type IEnumerable<> or by using the AsEnumerable extension method for example) so that the extension functions you call end up being the ones in the Enumerable class instead of the Queryable class.

Bootstrap - dropdown menu not working?

you are missing the "btn btn-navbar" section. For example:

        <a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
        </a>

Take a look to navbar documentation in:

Twitter Bootstrap

Extracting the top 5 maximum values in excel

To my mind the case for a PT (as @Nathan Fisher) is a 'no brainer', but I would add a column to facilitate ordering by rank (up or down):

SO18528624 first example

OPS is entered as VALUES (Sum of) twice so I have renamed the column labels to make clearer which is which. The PT is in a different sheet from the data but could be in the same sheet.

Rank is set with a right click on a data point selected in that column and Show Values As... and Rank Largest to Smallest (there are other options) with the Base field as Player and the filter is a Value Filters, Top 10... one:

SO18528624 second example

Once in a PT the power of that feature can very easily be applied to view the data in many other ways, with no change of formula (there isn't one!).

In the case of a tie for the last position included in the filter both results are included (Top 5 would show six or more results). A tie for top rank between just two players would show as 1 1 3 4 5 for Top 5.

WPF: Setting the Width (and Height) as a Percentage Value

I use two methods for relative sizing. I have a class called Relative with three attached properties To, WidthPercent and HeightPercent which is useful if I want an element to be a relative size of an element anywhere in the visual tree and feels less hacky than the converter approach - although use what works for you, that you're happy with.

The other approach is rather more cunning. Add a ViewBox where you want relative sizes inside, then inside that, add a Grid at width 100. Then if you add a TextBlock with width 10 inside that, it is obviously 10% of 100.

The ViewBox will scale the Grid according to whatever space it has been given, so if its the only thing on the page, then the Grid will be scaled out full width and effectively, your TextBlock is scaled to 10% of the page.

If you don't set a height on the Grid then it will shrink to fit its content, so it'll all be relatively sized. You'll have to ensure that the content doesn't get too tall, i.e. starts changing the aspect ratio of the space given to the ViewBox else it will start scaling the height as well. You can probably work around this with a Stretch of UniformToFill.

How do I tell if a regular file does not exist in Bash?

In

[ -f "$file" ]

the [ command does a stat() (not lstat()) system call on the path stored in $file and returns true if that system call succeeds and the type of the file as returned by stat() is "regular".

So if [ -f "$file" ] returns true, you can tell the file does exist and is a regular file or a symlink eventually resolving to a regular file (or at least it was at the time of the stat()).

However if it returns false (or if [ ! -f "$file" ] or ! [ -f "$file" ] return true), there are many different possibilities:

  • the file doesn't exist
  • the file exists but is not a regular file (could be a device, fifo, directory, socket...)
  • the file exists but you don't have search permission to the parent directory
  • the file exists but that path to access it is too long
  • the file is a symlink to a regular file, but you don't have search permission to some of the directories involved in the resolution of the symlink.
  • ... any other reason why the stat() system call may fail.

In short, it should be:

if [ -f "$file" ]; then
  printf '"%s" is a path to a regular file or symlink to regular file\n' "$file"
elif [ -e "$file" ]; then
  printf '"%s" exists but is not a regular file\n' "$file"
elif [ -L "$file" ]; then
  printf '"%s" exists, is a symlink but I cannot tell if it eventually resolves to an actual file, regular or not\n' "$file"
else
  printf 'I cannot tell if "%s" exists, let alone whether it is a regular file or not\n' "$file"
fi

To know for sure that the file doesn't exist, we'd need the stat() system call to return with an error code of ENOENT (ENOTDIR tells us one of the path components is not a directory is another case where we can tell the file doesn't exist by that path). Unfortunately the [ command doesn't let us know that. It will return false whether the error code is ENOENT, EACCESS (permission denied), ENAMETOOLONG or anything else.

The [ -e "$file" ] test can also be done with ls -Ld -- "$file" > /dev/null. In that case, ls will tell you why the stat() failed, though the information can't easily be used programmatically:

$ file=/var/spool/cron/crontabs/root
$ if [ ! -e "$file" ]; then echo does not exist; fi
does not exist
$ if ! ls -Ld -- "$file" > /dev/null; then echo stat failed; fi
ls: cannot access '/var/spool/cron/crontabs/root': Permission denied
stat failed

At least ls tells me it's not because the file doesn't exist that it fails. It's because it can't tell whether the file exists or not. The [ command just ignored the problem.

With the zsh shell, you can query the error code with the $ERRNO special variable after the failing [ command, and decode that number using the $errnos special array in the zsh/system module:

zmodload zsh/system
ERRNO=0
if [ ! -f "$file" ]; then
  err=$ERRNO
  case $errnos[err] in
    ("") echo exists, not a regular file;;
    (ENOENT|ENOTDIR)
       if [ -L "$file" ]; then
         echo broken link
       else
         echo does not exist
       fi;;
    (*) syserror -p "can't tell: " "$err"
  esac
fi

(beware the $errnos support was broken with some versions of zsh when built with recent versions of gcc).

How do I force Robocopy to overwrite files?

This is really weird, why nobody is mentioning the /IM switch ?! I've been using it for a long time in backup jobs. But I tried googling just now and I couldn't land on a single web page that says anything about it even on MS website !!! Also found so many user posts complaining about the same issue!!

Anyway.. to use Robocopy to overwrite EVERYTHING what ever size or time in source or distination you must include these three switches in your command (/IS /IT /IM)

/IS :: Include Same files. (Includes same size files)
/IT :: Include Tweaked files. (Includes same files with different Attributes)
/IM :: Include Modified files (Includes same files with different times).

This is the exact command I use to transfer few TeraBytes of mostly 1GB+ files (ISOs - Disk Images - 4K Videos):

robocopy B:\Source D:\Destination /E /J /COPYALL /MT:1 /DCOPY:DATE /IS /IT /IM /X /V /NP /LOG:A:\ROBOCOPY.LOG

I did a small test for you .. and here is the result:

               Total    Copied   Skipped  Mismatch    FAILED    Extras
    Dirs :      1028      1028         0         0         0       169
   Files :      8053      8053         0         0         0         1
   Bytes : 649.666 g 649.666 g         0         0         0   1.707 g
   Times :   2:46:53   0:41:43                       0:00:00   0:41:44


   Speed :           278653398 Bytes/sec.
   Speed :           15944.675 MegaBytes/min.
   Ended : Friday, August 21, 2020 7:34:33 AM

Dest, Disk: WD Gold 6TB (Compare the write speed with my result)

Even with those "Extras", that's for reporting only because of the "/X" switch. As you can see nothing was Skipped and Total number and size of all files are equal to the Copied. Sometimes It will show small number of skipped files when I abuse it and cancel it multiple times during operation but even with that the values in the first 2 columns are always Equal. I also confirmed that once before by running a PowerShell script that scans all files in destination and generate a report of all time-stamps.

Some performance tips from my history with it and so many tests & troubles!:

. Despite of what most users online advise to use maximum threads "/MT:128" like it's a general trick to get the best performance ... PLEASE DON'T USE "/MT:128" WITH VERY LARGE FILES ... that's a big mistake and it will decrease your drive performance dramatically after several runs .. it will create very high fragmentation or even cause the files system to fail in some cases and you end up spending valuable time trying to recover a RAW partition and all that nonsense. And above all that, It will perform 4-6 times slower!!

For very large files:

  1. Use Only "One" thread "/MT:1" | Impact: BIG
  2. Must use "/J" to disable buffering. | Impact: High
  3. Use "/NP" with "/LOG:file" and Don't output to the console by "/TEE" | Impact: Medium.
  4. Put the "/LOG:file" on a separate drive from the source or destination | Impact: Low.

For regular big files:

  1. Use multi threads, I would not exceed "/MT:4" | Impact: BIG
  2. IF destination disk has low Cache specs use "/J" to disable buffering | Impact: High
  3. & 4 same as above.

For thousands of tiny files:

  1. Go nuts :) with Multi threads, at first I would start with 16 and multibly by 2 while monitoring the disk performance. Once it starts dropping I'll fall back to the prevouse value and stik with it | Impact: BIG
  2. Don't use "/J" | Impact: High
  3. Use "/NP" with "/LOG:file" and Don't output to the console by "/TEE" | Impact: HIGH.
  4. Put the "/LOG:file" on a separate drive from the source or destination | Impact: HIGH.

Construct pandas DataFrame from items in nested dictionary

So I used to use a for loop for iterating through the dictionary as well, but one thing I've found that works much faster is to convert to a panel and then to a dataframe. Say you have a dictionary d

import pandas as pd
d
{'RAY Index': {datetime.date(2014, 11, 3): {'PX_LAST': 1199.46,
'PX_OPEN': 1200.14},
datetime.date(2014, 11, 4): {'PX_LAST': 1195.323, 'PX_OPEN': 1197.69},
datetime.date(2014, 11, 5): {'PX_LAST': 1200.936, 'PX_OPEN': 1195.32},
datetime.date(2014, 11, 6): {'PX_LAST': 1206.061, 'PX_OPEN': 1200.62}},
'SPX Index': {datetime.date(2014, 11, 3): {'PX_LAST': 2017.81,
'PX_OPEN': 2018.21},
datetime.date(2014, 11, 4): {'PX_LAST': 2012.1, 'PX_OPEN': 2015.81},
datetime.date(2014, 11, 5): {'PX_LAST': 2023.57, 'PX_OPEN': 2015.29},
datetime.date(2014, 11, 6): {'PX_LAST': 2031.21, 'PX_OPEN': 2023.33}}}

The command

pd.Panel(d)
<class 'pandas.core.panel.Panel'>
Dimensions: 2 (items) x 2 (major_axis) x 4 (minor_axis)
Items axis: RAY Index to SPX Index
Major_axis axis: PX_LAST to PX_OPEN
Minor_axis axis: 2014-11-03 to 2014-11-06

where pd.Panel(d)[item] yields a dataframe

pd.Panel(d)['SPX Index']
2014-11-03  2014-11-04  2014-11-05 2014-11-06
PX_LAST 2017.81 2012.10 2023.57 2031.21
PX_OPEN 2018.21 2015.81 2015.29 2023.33

You can then hit the command to_frame() to turn it into a dataframe. I use reset_index as well to turn the major and minor axis into columns rather than have them as indices.

pd.Panel(d).to_frame().reset_index()
major   minor      RAY Index    SPX Index
PX_LAST 2014-11-03  1199.460    2017.81
PX_LAST 2014-11-04  1195.323    2012.10
PX_LAST 2014-11-05  1200.936    2023.57
PX_LAST 2014-11-06  1206.061    2031.21
PX_OPEN 2014-11-03  1200.140    2018.21
PX_OPEN 2014-11-04  1197.690    2015.81
PX_OPEN 2014-11-05  1195.320    2015.29
PX_OPEN 2014-11-06  1200.620    2023.33

Finally, if you don't like the way the frame looks you can use the transpose function of panel to change the appearance before calling to_frame() see documentation here http://pandas.pydata.org/pandas-docs/dev/generated/pandas.Panel.transpose.html

Just as an example

pd.Panel(d).transpose(2,0,1).to_frame().reset_index()
major        minor  2014-11-03  2014-11-04  2014-11-05  2014-11-06
RAY Index   PX_LAST 1199.46    1195.323     1200.936    1206.061
RAY Index   PX_OPEN 1200.14    1197.690     1195.320    1200.620
SPX Index   PX_LAST 2017.81    2012.100     2023.570    2031.210
SPX Index   PX_OPEN 2018.21    2015.810     2015.290    2023.330

Hope this helps.

C# try catch continue execution

Or you can encapsulate the looping logic itself in a try catch e.g.

for(int i = function2(); i < 100 /*where 100 is the end or another function call to get the end*/; i = function2()){

    try{
     //ToDo
    }
    catch { continue; }    

}

Or...

try{ 
    for(int i = function2(); ; ;) {
        try { i = function2(); return; } 
        finally { /*decide to break or not :P*/continue; } }
} catch { /*failed on first try*/ } finally{ /*afterwardz*/ }

Stylesheet not updating

I had same issue. One of the reasons was, my application was cached and I was performing local build.

I would prefer deleting the css file and re-adding it again with changes if none of the above comments work.

How to align linearlayout to vertical center?

For me, I have fixed the problem using android:layout_centerVertical="true" in a parent RelativeLayout:

<RelativeLayout ... >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_centerVertical="true">

</RelativeLayout>

ASP.NET MVC Dropdown List From SelectList

Just try this in razor

@{
    var selectList = new SelectList(
        new List<SelectListItem>
        {
            new SelectListItem {Text = "Google", Value = "Google"},
            new SelectListItem {Text = "Other", Value = "Other"},
        }, "Value", "Text");
}

and then

@Html.DropDownListFor(m => m.YourFieldName, selectList, "Default label", new { @class = "css-class" })

or

@Html.DropDownList("ddlDropDownList", selectList, "Default label", new { @class = "css-class" })

How to sum the values of a JavaScript object?

If you're using lodash you can do something like

_.sum(_.values({ 'a': 1 , 'b': 2 , 'c':3 })) 

Spring 3 MVC accessing HttpRequest from controller

Spring MVC will give you the HttpRequest if you just add it to your controller method signature:

For instance:

/**
 * Generate a PDF report...
 */
@RequestMapping(value = "/report/{objectId}", method = RequestMethod.GET)
public @ResponseBody void generateReport(
        @PathVariable("objectId") Long objectId, 
        HttpServletRequest request, 
        HttpServletResponse response) {

    // ...
    // Here you can use the request and response objects like:
    // response.setContentType("application/pdf");
    // response.getOutputStream().write(...);

}

As you see, simply adding the HttpServletRequest and HttpServletResponse objects to the signature makes Spring MVC to pass those objects to your controller method. You'll want the HttpSession object too.

EDIT: It seems that HttpServletRequest/Response are not working for some people under Spring 3. Try using Spring WebRequest/WebResponse objects as Eduardo Zola pointed out.

I strongly recommend you to have a look at the list of supported arguments that Spring MVC is able to auto-magically inject to your handler methods.

SwiftUI - How do I change the background color of a View?

The code on Scene delegate in Swift UI

Content view background-color

window.rootViewController?.view.backgroundColor = .lightGray

bind/unbind service example (android)

You can try using this code:

protected ServiceConnection mServerConn = new ServiceConnection() {
    @Override
    public void onServiceConnected(ComponentName name, IBinder binder) {
        Log.d(LOG_TAG, "onServiceConnected");
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        Log.d(LOG_TAG, "onServiceDisconnected");
    }
}

public void start() {
    // mContext is defined upper in code, I think it is not necessary to explain what is it 
    mContext.bindService(intent, mServerConn, Context.BIND_AUTO_CREATE);
    mContext.startService(intent);
}

public void stop() {
    mContext.stopService(new Intent(mContext, ServiceRemote.class));
    mContext.unbindService(mServerConn);
}

CodeIgniter Select Query

public function getSalary()
    {
        $this->db->select('tbl_salary.*,tbl_employee.empFirstName');
        $this->db->from('tbl_salary');
        $this->db->join('tbl_employee','tbl_employee.empID = strong texttbl_salary.salEmpID');
        $this->db->where('tbl_salary.status',0);
        $query = $this->db->get();
        return $query->result();
    }

How to bring view in front of everything?

You can call bringToFront() on the view you want to get in the front

This is an example:

    yourView.bringToFront();

How do I change select2 box height

Just add in select2.css

/* Make Select2 boxes match Bootstrap3 as well as Bootstrap4 heights: */
.select2-selection__rendered {
line-height: 32px !important;
}

.select2-selection {
height: 34px !important;
}

Stretch background image css?

.style1 {
  background: url(images/bg.jpg) no-repeat center center fixed;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

Works in:

  • Safari 3+
  • Chrome Whatever+
  • IE 9+
  • Opera 10+ (Opera 9.5 supported background-size but not the keywords)
  • Firefox 3.6+ (Firefox 4 supports non-vendor prefixed version)

In addition you can try this for an IE solution

filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='.myBackground.jpg', sizingMethod='scale');
-ms-filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='myBackground.jpg', sizingMethod='scale')";
zoom: 1;

Credit to this article by Chris Coyier http://css-tricks.com/perfect-full-page-background-image/

IE11 prevents ActiveX from running

We started finding some machines with IE 11 not playing video (via flash) after we set the emulation mode of our app (web browser control) to 110001. Adding the meta tag to our htm files worked for us.

Convert string to Time

string Time = "16:23:01";
DateTime date = DateTime.Parse(Time, System.Globalization.CultureInfo.CurrentCulture);

string t = date.ToString("HH:mm:ss tt");

What is the syntax of the enhanced for loop in Java?

  1. Enhanced For Loop (Java)
for (Object obj : list);
  1. Enhanced For Each in arraylist (Java)
ArrayList<Integer> list = new ArrayList<Integer>(); 
list.forEach((n) -> System.out.println(n)); 

VBA macro that search for file in multiple subfolders

If this helps, you can also use FileSystemObject to retrieve all subfolders of a folder. You need to check the reference "Microsot Scripting Runtime" to get Intellisense and use the "new" keyword.

Sub GetSubFolders()

    Dim fso As New FileSystemObject
    Dim f As Folder, sf As Folder

    Set f = fso.GetFolder("D:\Proj\")
    For Each sf In f.SubFolders
        'Code inside
    Next

End Sub

Find substring in the string in TWIG

Just searched for the docs, and found this:

Containment Operator: The in operator performs containment test. It returns true if the left operand is contained in the right:

{# returns true #}

{{ 1 in [1, 2, 3] }}

{{ 'cd' in 'abcde' }}

How to get StackPanel's children to fill maximum space downward?

It sounds like you want a StackPanel where the final element uses up all the remaining space. But why not use a DockPanel? Decorate the other elements in the DockPanel with DockPanel.Dock="Top", and then your help control can fill the remaining space.

XAML:

<DockPanel Width="200" Height="200" Background="PowderBlue">
    <TextBlock DockPanel.Dock="Top">Something</TextBlock>
    <TextBlock DockPanel.Dock="Top">Something else</TextBlock>
    <DockPanel
        HorizontalAlignment="Stretch" 
        VerticalAlignment="Stretch" 
        Height="Auto" 
        Margin="10">

      <GroupBox 
        DockPanel.Dock="Right" 
        Header="Help" 
        Width="100" 
        Background="Beige" 
        VerticalAlignment="Stretch" 
        VerticalContentAlignment="Stretch" 
        Height="Auto">
        <TextBlock Text="This is the help that is available on the news screen." 
                   TextWrapping="Wrap" />
     </GroupBox>

      <StackPanel DockPanel.Dock="Left" Margin="10" 
           Width="Auto" HorizontalAlignment="Stretch">
          <TextBlock Text="Here is the news that should wrap around." 
                     TextWrapping="Wrap"/>
      </StackPanel>
    </DockPanel>
</DockPanel>

If you are on a platform without DockPanel available (e.g. WindowsStore), you can create the same effect with a grid. Here's the above example accomplished using grids instead:

<Grid Width="200" Height="200" Background="PowderBlue">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <StackPanel Grid.Row="0">
        <TextBlock>Something</TextBlock>
        <TextBlock>Something else</TextBlock>
    </StackPanel>
    <Grid Height="Auto" Grid.Row="1" Margin="10">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="100"/>
        </Grid.ColumnDefinitions>
        <GroupBox
            Width="100"
            Height="Auto"
            Grid.Column="1"
            Background="Beige"
            Header="Help">
            <TextBlock Text="This is the help that is available on the news screen." 
              TextWrapping="Wrap"/>
        </GroupBox>
        <StackPanel Width="Auto" Margin="10" DockPanel.Dock="Left">
            <TextBlock Text="Here is the news that should wrap around." 
              TextWrapping="Wrap"/>
        </StackPanel>
    </Grid>
</Grid>

Python Replace \\ with \

It's because, even in "raw" strings (=strings with an r before the starting quote(s)), an unescaped escape character cannot be the last character in the string. This should work instead:

'\\ '[0]

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

HTML:

<div id="parent">
  <div class="right"></div>
  <div class="left"></div>
</div>

(div.right needs to be before div.left in the HTML markup)

CSS:

.right {
float:right;
width:200px;
}

Installing Python 2.7 on Windows 8

Easiest way is to open CMD or powershell as administrator and type

set PATH=%PATH%;C:\Python27

How exactly does __attribute__((constructor)) work?

  1. It runs when a shared library is loaded, typically during program startup.
  2. That's how all GCC attributes are; presumably to distinguish them from function calls.
  3. GCC-specific syntax.
  4. Yes, this works in C and C++.
  5. No, the function does not need to be static.
  6. The destructor runs when the shared library is unloaded, typically at program exit.

So, the way the constructors and destructors work is that the shared object file contains special sections (.ctors and .dtors on ELF) which contain references to the functions marked with the constructor and destructor attributes, respectively. When the library is loaded/unloaded the dynamic loader program (ld.so or somesuch) checks whether such sections exist, and if so, calls the functions referenced therein.

Come to think of it, there is probably some similar magic in the normal static linker so that the same code is run on startup/shutdown regardless if the user chooses static or dynamic linking.

How to catch and print the full exception traceback without halting/exiting the program?

Some other answer have already pointed out the traceback module.

Please notice that with print_exc, in some corner cases, you will not obtain what you would expect. In Python 2.x:

import traceback

try:
    raise TypeError("Oups!")
except Exception, err:
    try:
        raise TypeError("Again !?!")
    except:
        pass

    traceback.print_exc()

...will display the traceback of the last exception:

Traceback (most recent call last):
  File "e.py", line 7, in <module>
    raise TypeError("Again !?!")
TypeError: Again !?!

If you really need to access the original traceback one solution is to cache the exception infos as returned from exc_info in a local variable and display it using print_exception:

import traceback
import sys

try:
    raise TypeError("Oups!")
except Exception, err:
    try:
        exc_info = sys.exc_info()

        # do you usefull stuff here
        # (potentially raising an exception)
        try:
            raise TypeError("Again !?!")
        except:
            pass
        # end of useful stuff


    finally:
        # Display the *original* exception
        traceback.print_exception(*exc_info)
        del exc_info

Producing:

Traceback (most recent call last):
  File "t.py", line 6, in <module>
    raise TypeError("Oups!")
TypeError: Oups!

Few pitfalls with this though:

  • From the doc of sys_info:

    Assigning the traceback return value to a local variable in a function that is handling an exception will cause a circular reference. This will prevent anything referenced by a local variable in the same function or by the traceback from being garbage collected. [...] If you do need the traceback, make sure to delete it after use (best done with a try ... finally statement)

  • but, from the same doc:

    Beginning with Python 2.2, such cycles are automatically reclaimed when garbage collection is enabled and they become unreachable, but it remains more efficient to avoid creating cycles.


On the other hand, by allowing you to access the traceback associated with an exception, Python 3 produce a less surprising result:

import traceback

try:
    raise TypeError("Oups!")
except Exception as err:
    try:
        raise TypeError("Again !?!")
    except:
        pass

    traceback.print_tb(err.__traceback__)

... will display:

  File "e3.py", line 4, in <module>
    raise TypeError("Oups!")

How to sort an array of objects in Java?

[Employee(name=John, age=25, salary=3000.0, mobile=9922001), 
Employee(name=Ace, age=22, salary=2000.0, mobile=5924001), 
Employee(name=Keith, age=35, salary=4000.0, mobile=3924401)]


public void whenComparing_thenSortedByName() {
Comparator<Employee> employeeNameComparator
  = Comparator.comparing(Employee::getName);

Arrays.sort(employees, employeeNameComparator);

assertTrue(Arrays.equals(employees, sortedEmployeesByName));

}

result

[Employee(name=Ace, age=22, salary=2000.0, mobile=5924001), 
Employee(name=John, age=25, salary=3000.0, mobile=9922001), 
Employee(name=Keith, age=35, salary=4000.0, mobile=3924401)]

How to make Twitter Bootstrap tooltips have multiple lines?

In Angular UI Bootstrap 0.13.X, tooltip-html-unsafe has been deprecated. You should now use tooltip-html and $sce.trustAsHtml() to accomplish a tooltip with html.

https://github.com/angular-ui/bootstrap/commit/e31fcf0fcb06580064d1e6375dbedb69f1c95f25

<a href="#" tooltip-html="htmlTooltip">Check me out!</a>

$scope.htmlTooltip = $sce.trustAsHtml('I\'ve been made <b>bold</b>!');

Sort an array of objects in React and render them

Try lodash sortBy

import * as _ from "lodash";
_.sortBy(data.applications,"id").map(application => (
    console.log("application")
    )
)

Read more : lodash.sortBy

Java: Finding the highest value in an array

import java.util.*;
class main9 //Find the smallest and 2lagest and  ascending and descending order of  elements in array//
{
    public static void main(String args[])
    {
        Scanner sc=new Scanner(System.in);
        System.out.println("Enter the array range");
        int no=sc.nextInt();
        System.out.println("Enter the array element");
        int a[]=new int[no];
        int i;
        for(i=0;i<no;i++)
        {
            a[i]=sc.nextInt();
        }
        Arrays.sort(a);
        int s=a[0];
        int l=a[a.length-1];
        int m=a[a.length-2];
        System.out.println("Smallest no is="+s);
        System.out.println("lagest 2 numbers are=");
        System.out.println(l);
        System.out.println(m);
        System.out.println("Array in ascending:");
        for(i=0;i<no;i++)
        {
            System.out.println(a[i]);
        }
        System.out.println("Array in descending:");
        for(i=a.length-1;i>=0;i--)
        {
            System.out.println(a[i]);
        }
    }
}

Adding HTML entities using CSS content

In CSS you need to use a Unicode escape sequence in place of HTML Entities. This is based on the hexadecimal value of a character.

I found that the easiest way to convert symbol to their hexadecimal equivalent is, such as from ▾ (&#9662;) to \25BE is to use the Microsoft calculator =)

Yes. Enable programmers mode, turn on the decimal system, enter 9662, then switch to hex and you'll get 25BE. Then just add a backslash \ to the beginning.

How to check whether an array is empty using PHP?

Making the most appropriate decision requires knowing the quality of your data and what processes are to follow.

  1. If you are going to disqualify/disregard/remove this row, then the earliest point of filtration should be in the mysql query.
  • WHERE players IS NOT NULL
  • WHERE players != ''
  • WHERE COALESCE(players, '') != ''
  • WHERE players IS NOT NULL AND players != ''
  • ...it kind of depends on your store data and there will be other ways, I'll stop here.
  1. If you aren't 100% sure if the column will exist in the result set, then you should check that the column is declared. This will mean calling array_key_exists(), isset(), or empty() on the column. I am not going to bother delineating the differences here (there are other SO pages for that breakdown, here's a start: 1, 2, 3). That said, if you aren't in total control of the result set, then maybe you have over-indulged application "flexibility" and should rethink if the trouble of potentially accessing non-existent column data is worth it. Effectively, I am saying that you should never need to check if a column is declared -- ergo you should never need empty() for this task. If anyone is arguing that empty() is more appropriate, then they are pushing their own personal opinion about expressiveness of scripting. If you find the condition in #5 below to be ambiguous, add an inline comment to your code -- but I wouldn't. The bottom line is that there is no programmatical advantage to making the function call.

  2. Might your string value contain a 0 that you want to deem true/valid/non-empty? If so, then you only need to check if the column value has length.

Here is a Demo using strlen(). This will indicated whether or not the string will create meaningful array elements if exploded.

  1. I think it is important to mention that by unconditionally exploding, you are GUARANTEED to generate a non-empty array. Here's proof: Demo In other words, checking if the array is empty is completely useless -- it will be non-empty every time.

  2. If your string will NOT POSSIBLY contain a zero value (because, say, this is a csv consisting of ids which start from 1 and only increment), then if ($gamerow['players']) { is all you need -- end of story.

  3. ...but wait, what are you doing after determining the emptiness of this value? If you have something down-script that is expecting $playerlist, but you are conditionally declaring that variable, then you risk using the previous row's value or again generating Notices. So do you need to unconditionally declare $playerlist as something? If there are no truthy values in the string, does your application benefit from declaring an empty array? Chances are, the answer is yes. In this case, you can ensure that the variable is array-type by falling back to an empty array -- this way it won't matter if you feed that variable into a loop. The following conditional declarations are all equivalent.

  • if ($gamerow['players']) { $playerlist = explode(',', $gamerow['players']); } else { $playerlist = []; }
  • $playerlist = $gamerow['players'] ? explode(',', $gamerow['players']) : [];

Why have I gone to such length to explain this very basic task?

  1. I have whistleblown nearly every answer on this page and this answer is likely to draw revenge votes (this happens often to whistleblowers who defend this site -- if an answer has downvotes and no comments, always be skeptical).
  2. I think it is important that Stackoverflow is a trusted resource that doesn't poison researchers with misinformation and suboptimal techniques.
  3. This is how I show how much I care about upcoming developers so that they learn the how and the why instead of just spoon-feeding a generation of copy-paste programmers.
  4. I frequently use old pages to close new duplicate pages -- this is the responsibility of veteran volunteers who know how to quickly find duplicates. I cannot bring myself to use an old page with bad/false/suboptimal/misleading information as a reference because then I am actively doing a disservice to a new researcher.

Using the Web.Config to set up my SQL database connection string?

If you are using SQL Express (which you are), then your login credentials are .\SQLEXPRESS

Here is the connectionString in the web config file which you can add:

<connectionStrings>
<add connectionString="Server=localhost\SQLEXPRESS;Database=yourDBName;Initial Catalog= yourDBName;Integrated Security=true" name="nametoCallBy" providerName="System.Data.SqlClient"/>
</connectionStrings>

Place is just above the system.web tag.

Then you can call it by:

connString = ConfigurationManager.ConnectionStrings["nametoCallBy"].ConnectionString;

Powershell Log Off Remote Session

Below script will work well for both active and disconnected sessions as long as user has access to run logoff command remotely. All you have to do is change the servername from "YourServerName" on 4th line.

param (
    $queryResults = $null,
    [string]$UserName = $env:USERNAME,
    [string]$ServerName = "YourServerName"
)


if (Test-Connection $ServerName -Count 1 -Quiet) {  
    Write-Host "`n`n`n$ServerName is online!" -BackgroundColor Green -ForegroundColor Black


    Write-Host ("`nQuerying Server: `"$ServerName`" for disconnected sessions under UserName: `"" + $UserName.ToUpper() + "`"...") -BackgroundColor Gray -ForegroundColor Black

        query user $UserName /server:$ServerName 2>&1 | foreach {  

            if ($_ -match "Active") {
                Write-Host "Active Sessions"
                $queryResults = ("`n$ServerName," + (($_.trim() -replace ' {2,}', ','))) | ConvertFrom-Csv -Delimiter "," -Header "ServerName","UserName","SessionName","SessionID","CurrentState","IdealTime","LogonTime"


                $queryResults | ft
                Write-Host "Starting logoff procedure..." -BackgroundColor Gray -ForegroundColor Black

                $queryResults | foreach {
                    $Sessionl = $_.SessionID
                    $Serverl = $_.ServerName
                    Write-Host "Logging off"$_.username"from $serverl..." -ForegroundColor black -BackgroundColor Gray
                    sleep 2
                    logoff $Sessionl /server:$Serverl /v

                }


            }                
            elseif ($_ -match "Disc") {
                Write-Host "Disconnected Sessions"
                $queryResults = ("`n$ServerName," + (($_.trim() -replace ' {2,}', ','))) |  ConvertFrom-Csv -Delimiter "," -Header "ServerName","UserName","SessionID","CurrentState","IdealTime","LogonTime"

                $queryResults | ft
                Write-Host "Starting logoff procedure..." -BackgroundColor Gray -ForegroundColor Black

                $queryResults | foreach {
                    $Sessionl = $_.SessionID
                    $Serverl = $_.ServerName
                    Write-Host "Logging off"$_.username"from $serverl..."
                    sleep 2
                    logoff $Sessionl /server:$Serverl /v

                }
            }
            elseif ($_ -match "The RPC server is unavailable") {

                Write-Host "Unable to query the $ServerName, check for firewall settings on $ServerName!" -ForegroundColor White -BackgroundColor Red
            }
            elseif ($_ -match "No User exists for") {Write-Host "No user session exists"}

    }
}
else {

    Write-Host "`n`n`n$ServerName is Offline!" -BackgroundColor red -ForegroundColor white
    Write-Host "Error: Unable to connect to $ServerName!" -BackgroundColor red -ForegroundColor white
    Write-Host "Either the $ServerName is down or check for firewall settings on server $ServerName!" -BackgroundColor Yellow -ForegroundColor black
}





Read-Host "`n`nScript execution finished, press enter to exit!"

Some sample outputs. For active session: enter image description here

For disconnected sessions: enter image description here

if no sessions found: enter image description here Check out this solution as well to query all AD servers for your username and logoff only disconnected sessions. The script will also tell you if there were error connecting or querying the server.

Powershell to find out disconnected RDP session and log off at the same time

OnItemClickListener using ArrayAdapter for ListView

you can use this way...

listView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                final int position, long id) {

          String main = listView.getSelectedItem().toString();
        }
    });

LINQ Join with Multiple Conditions in On Clause

This works fine for 2 tables. I have 3 tables and on clause has to link 2 conditions from 3 tables. My code:

from p in _dbContext.Products join pv in _dbContext.ProductVariants on p.ProduktId equals pv.ProduktId join jpr in leftJoinQuery on new { VariantId = pv.Vid, ProductId = p.ProduktId } equals new { VariantId = jpr.Prices.VariantID, ProductId = jpr.Prices.ProduktID } into lj

But its showing error at this point: join pv in _dbContext.ProductVariants on p.ProduktId equals pv.ProduktId

Error: The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'GroupJoin'.

Using local makefile for CLion instead of CMake

Update: If you are using CLion 2020.2, then it already supports Makefiles. If you are using an older version, read on.


Even though currently only CMake is supported, you can instruct CMake to call make with your custom Makefile. Edit your CMakeLists.txt adding one of these two commands:

When you tell CLion to run your program, it will try to find an executable with the same name of the target in the directory pointed by PROJECT_BINARY_DIR. So as long as your make generates the file where CLion expects, there will be no problem.

Here is a working example:

Tell CLion to pass its $(PROJECT_BINARY_DIR) to make

This is the sample CMakeLists.txt:

cmake_minimum_required(VERSION 2.8.4)
project(mytest)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

add_custom_target(mytest COMMAND make -C ${mytest_SOURCE_DIR}
                         CLION_EXE_DIR=${PROJECT_BINARY_DIR})

Tell make to generate the executable in CLion's directory

This is the sample Makefile:

all:
    echo Compiling $(CLION_EXE_DIR)/$@ ...
    g++ mytest.cpp -o $(CLION_EXE_DIR)/mytest

That is all, you may also want to change your program's working directory so it executes as it is when you run make from inside your directory. For this edit: Run -> Edit Configurations ... -> mytest -> Working directory

Find everything between two XML tags with RegEx

It is not a good idea to use regex for HTML/XML parsing...

However, if you want to do it anyway, search for regex pattern

<primaryAddress>[\s\S]*?<\/primaryAddress>

and replace it with empty string...

WebView showing ERR_CLEARTEXT_NOT_PERMITTED although site is HTTPS

When you call "https://darkorbit.com/" your server figures that it's missing "www" so it redirects the call to "http://www.darkorbit.com/" and then to "https://www.darkorbit.com/", your WebView call is blocked at the first redirection as it's a "http" call. You can call "https://www.darkorbit.com/" instead and it will solve the issue.

TortoiseSVN icons not showing up under Windows 7

I had same problem here with TortoiseSVN 1.6.16. Icons were fine, but then I installed and uninstalled TortoiseGit and suddenly the TortoiseSVN icons stopped working. Looking at the registry I discovered that uninstalling TortoiseGit also removed all overlay icons. I simply reinstalled TortoiseSVN and it fixed the issue.

Smooth scroll to div id jQuery

here is my 2 cents:

Javascript:

$('.scroll').click(function() {
    $('body').animate({
        scrollTop: eval($('#' + $(this).attr('target')).offset().top - 70)
    }, 1000);
});

Html:

<a class="scroll" target="contact">Contact</a>

and the target:

<h2 id="contact">Contact</h2>

Do a "git export" (like "svn export")?

i have the following utility function in my .bashrc file: it creates an archive of the current branch in a git repository.

function garchive()
{
  if [[ "x$1" == "x-h" || "x$1" == "x" ]]; then
    cat <<EOF
Usage: garchive <archive-name>
create zip archive of the current branch into <archive-name>
EOF
  else
    local oname=$1
    set -x
    local bname=$(git branch | grep -F "*" | sed -e 's#^*##')
    git archive --format zip --output ${oname} ${bname}
    set +x
  fi
}

Adding rows dynamically with jQuery

Building on the other answers, I simplified things a bit. By cloning the last element, we get the "add new" button for free (you have to change the ID to a class because of the cloning) and also reduce DOM operations. I had to use filter() instead of find() to get only the last element.

$('.js-addNew').on('click', function(e) {
   e.preventDefault();
   var $rows   = $('.person'),
       $last   = $rows.filter(':last'),
       $newRow = $last.clone().insertAfter($last);

   $last.find($('.js-addNew')).remove(); // remove old button
   $newRow.hide().find('input').val('');
   $newRow.slideDown(500);
});

Executing Javascript from Python

One more solution as PyV8 seems to be unmaintained and dependent on the old version of libv8.

PyMiniRacer It's a wrapper around the v8 engine and it works with the new version and is actively maintained.

pip install py-mini-racer

from py_mini_racer import py_mini_racer
ctx = py_mini_racer.MiniRacer()
ctx.eval("""
function escramble_758(){
    var a,b,c
    a='+1 '
    b='84-'
    a+='425-'
    b+='7450'
    c='9'
    return a+c+b;
}
""")
ctx.call("escramble_758")

And yes, you have to replace document.write with return as others suggested

Adding a UISegmentedControl to UITableView

   self.tableView.tableHeaderView = segmentedControl; 

If you want it to obey your width and height properly though enclose your segmentedControl in a UIView first as the tableView likes to mangle your view a bit to fit the width.

enter image description here enter image description here

Setting focus to a textbox control

create a textbox:

 <TextBox Name="tb">
 ..hello..
</TextBox>

focus() ---> it is used to set input focus to the textbox control

tb.focus()

PHP CURL DELETE request

    $json empty

public function deleteUser($extid)
{
    $path = "/rest/user/".$extid."/;token=".$this->__token;
    $result = $this->curl_req($path,"**$json**","DELETE");
    return $result;

}

Setting background color for a JFrame

import java.awt.*;
import javax.swing.*;

public class MySimpleLayout extends JFrame {

        private Container c;
        public MySimpleLayout(String str) {
            super(str);
            c=getContentPane();
            c.setLayout(null);
            c.setBackground(Color.WHITE);
        }
}

How to find all tables that have foreign keys that reference particular table.column and have values for those foreign keys?

You can find all schema related information in the wisely named information_schema table.

You might want to check the table REFERENTIAL_CONSTRAINTS and KEY_COLUMN_USAGE. The former tells you which tables are referenced by others; the latter will tell you how their fields are related.

What is the facade design pattern?

A facade should not be described as a class which contains a lot of other classes. It is in fact a interface to this classes and should make the usage of the classes easier otherwise the facade class is useless.

'was not declared in this scope' error

Here's a simplified example based on of your problem:

if (test) 
{//begin scope 1
    int y = 1; 
}//end scope 1
else 
{//begin scope 2
    int y = 2;//error, y is not in scope
}//end scope 2
int x = y;//error, y is not in scope

In the above version you have a variable called y that is confined to scope 1, and another different variable called y that is confined to scope 2. You then try to refer to a variable named y after the end of the if, and not such variable y can be seen because no such variable exists in that scope.

You solve the problem by placing y in the outermost scope which contains all references to it:

int y;
if (test) 
{
    y = 1; 
}
else 
{
    y = 2;
}
int x = y;

I've written the example with simplified made up code to make it clearer for you to understand the issue. You should now be able to apply the principle to your code.

How to open VMDK File of the Google-Chrome-OS bundle 2012?

For me my vmdk file was accompanied by a vmx file. Opening the vmx file worked for vmware player.

Multiple bluetooth connection

Have you looked into the BluetoothAdapter Android class? You set up one device as a server and the other as a client. It may be possible (although I haven't looked into it myself) to connect multiple clients to the server.

I have had success connecting a BlueTooth audio device to a phone while it also had this BluetoothAdapter connection to another phone, but I haven't tried with three phones. At least this tells me that the Bluetooth radio can tolerate multiple simultaneous connections :)

Singleton design pattern vs Singleton beans in Spring container

There is a very fundamental difference between the two. In case of Singleton design pattern, only one instance of a class will be created per classLoader while that is not the case with Spring singleton as in the later one shared bean instance for the given id per IoC container is created.

For example, if I have a class with the name "SpringTest" and my XML file looks something like this :-

<bean id="test1" class="com.SpringTest" scope="singleton">
        --some properties here
</bean>    
<bean id="test2" class="com.SpringTest" scope="singleton">
        --some properties here   
</bean>

So now in the main class if you will check the reference of the above two it will return false as according to Spring documentation:-

When a bean is a singleton, only one shared instance of the bean will be managed, and all requests for beans with an id or ids matching that bean definition will result in that one specific bean instance being returned by the Spring container

So as in our case, the classes are the same but the id's that we have provided are different hence resulting in two different instances being created.

How can I get last characters of a string

Performance

Today 2020.12.31 I perform tests on MacOs HighSierra 10.13.6 on Chrome v87, Safari v13.1.2 and Firefox v84 for chosen solutions for getting last N characters case (last letter case result, for clarity I present in separate answer).

Results

For all browsers

  • solution D based on slice is fast or fastest
  • solution G is slowest

enter image description here

Details

I perform 2 tests cases:

  • when string has 10 chars - you can run it HERE
  • when string has 1M chars - you can run it HERE

Below snippet presents solutions A B C D E F G (my)

_x000D_
_x000D_
//https://stackoverflow.com/questions/5873810/how-can-i-get-last-characters-of-a-string

// https://stackoverflow.com/a/30916653/860099
function A(s,n) {
  return s.substr(-n)
}

// https://stackoverflow.com/a/5873890/860099
function B(s,n) {
  return s.substr(s.length - n)
}

// https://stackoverflow.com/a/17489443/860099
function C(s,n) {
  return s.substring(s.length - n, s.length);
}

// https://stackoverflow.com/a/50395190/860099
function D(s,n) {
  return s.slice(-n);
}

// https://stackoverflow.com/a/50374396/860099
function E(s,n) {
  let i = s.length-n;
  let r = '';
  while(i<s.length) r += s.charAt(i++);
  return r
}

// https://stackoverflow.com/a/17489443/860099
function F(s,n) {
  let i = s.length-n;
  let r = '';
  while(i<s.length) r += s[i++];
  return r
}

// my
function G(s,n) {
  return s.match(new RegExp(".{"+n+"}$"));
}

// --------------------
// TEST
// --------------------

[A,B,C,D,E,F,G].map(f=> {  
  console.log(
    f.name + ' ' + f('ctl03_Tabs1',5)
  )})
_x000D_
This shippet only presents functions used in performance tests - it not perform tests itself!
_x000D_
_x000D_
_x000D_

And here are example results for chrome

enter image description here

Django: List field in model?

You can flatten the list and then store the values to a CommaSeparatedIntegerField. When you read back from the database, just group the values back into threes.

Disclaimer: according to database normalization theory, it is better not to store collections in single fields; instead you would be encouraged to store the values in those triplets in their own fields and link them via foreign keys. In the real world, though, sometimes that is too cumbersome/slow.

Get textarea text with javascript or Jquery

Get textarea text with JavaScript:

<!DOCTYPE html>
<body>
<form id="form1">
    <div>
        <textarea id="area1" rows="5">Yes</textarea>
        <input type="button" value="get txt" onclick="go()" />
        <br />
        <p id="as">Now what</p>
    </div>
</form>
</body>

function go() {
    var c1 = document.getElementById('area1').value;
    var d1 = document.getElementById('as');
    d1.innerHTML = c1;
}

http://jsfiddle.net/PUpeJ/3/

onchange event on input type=range is not triggering in firefox while dragging

Apparently Chrome and Safari are wrong: onchange should only be triggered when the user releases the mouse. To get continuous updates, you should use the oninput event, which will capture live updates in Firefox, Safari and Chrome, both from the mouse and the keyboard.

However, oninput is not supported in IE10, so your best bet is to combine the two event handlers, like this:

<span id="valBox"></span>
<input type="range" min="5" max="10" step="1" 
   oninput="showVal(this.value)" onchange="showVal(this.value)">

Check out this Bugzilla thread for more information.

How do you delete an ActiveRecord object?

It's destroy and destroy_all methods, like

user.destroy
User.find(15).destroy
User.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)

Alternatively you can use delete and delete_all which won't enforce :before_destroy and :after_destroy callbacks or any dependent association options.

User.delete_all(condition: 'value') will allow you to delete records without a primary key

Note: from @hammady's comment, user.destroy won't work if User model has no primary key.

Note 2: From @pavel-chuchuva's comment, destroy_all with conditions and delete_all with conditions has been deprecated in Rails 5.1 - see guides.rubyonrails.org/5_1_release_notes.html

How to unpackage and repackage a WAR file

copy your war file to /tmp now extract the contents:

cp warfile.war /tmp
cd /tmp
unzip warfile.war
cd WEB-INF
nano web.xml (or vim or any editor you want to use)
cd ..
zip -r -u warfile.war WEB-INF

now you have in /tmp/warfile.war your file updated.

How can I brew link a specific version?

The usage info:

Usage: brew switch <formula> <version>

Example:

brew switch mysql 5.5.29

You can find the versions installed on your system with info.

brew info mysql

And to see the available versions to install, you can provide a dud version number, as brew will helpfully respond with the available version numbers:

brew switch mysql 0

Update (15.10.2014):

The brew versions command has been removed from brew, but, if you do wish to use this command first run brew tap homebrew/boneyard.

The recommended way to install an old version is to install from the homebrew/versions repo as follows:

$ brew tap homebrew/versions
$ brew install mysql55

For detailed info on all the ways to install an older version of a formula read this answer.

How to specify Memory & CPU limit in docker compose version 3

Docker Compose does not support the deploy key. It's only respected when you use your version 3 YAML file in a Docker Stack.

This message is printed when you add the deploy key to you docker-compose.yml file and then run docker-compose up -d

WARNING: Some services (database) use the 'deploy' key, which will be ignored. Compose does not support 'deploy' configuration - use docker stack deploy to deploy to a swarm.

The documentation (https://docs.docker.com/compose/compose-file/#deploy) says:

Specify configuration related to the deployment and running of services. This only takes effect when deploying to a swarm with docker stack deploy, and is ignored by docker-compose up and docker-compose run.

Tool to Unminify / Decompress JavaScript

Wasn't really happy with the output of jsbeautifier.org for what I was putting in, so I did some more searching and found this site: http://www.centralinternet.com.br/javascript-beautifier

Worked extremely well for me.

Getting Keyboard Input

You can use Scanner class

Import first :

import java.util.Scanner;

Then you use like this.

Scanner keyboard = new Scanner(System.in);
System.out.println("enter an integer");
int myint = keyboard.nextInt();

Side note : If you are using nextInt() with nextLine() you probably could have some trouble cause nextInt() does not read the last newline character of input and so nextLine() then is not gonna to be executed with desired behaviour. Read more in how to solve it in this previous question Skipping nextLine using nextInt.

Using margin:auto to vertically-align a div

Update Aug 2020

Although the below is still worth reading for the useful info, we have had Flexbox for some time now, so just use that, as per this answer.


You can't use:

vertical-align:middle because it's not applicable to block-level elements

margin-top:auto and margin-bottom:auto because their used values would compute as zero

margin-top:-50% because percentage-based margin values are calculated relative to the width of containing block

In fact, the nature of document flow and element height calculation algorithms make it impossible to use margins for centering an element vertically inside its parent. Whenever a vertical margin's value is changed, it will trigger a parent element height re-calculation (re-flow), which would in turn trigger a re-center of the original element... making it an infinite loop.

You can use:

A few workarounds like this which work for your scenario; the three elements have to be nested like so:

_x000D_
_x000D_
.container {
    display: table;
    height: 100%;
    position: absolute;
    overflow: hidden;
    width: 100%;
}
.helper {
    #position: absolute;
    #top: 50%;
    display: table-cell;
    vertical-align: middle;
}
.content {
    #position: relative;
    #top: -50%;
    margin: 0 auto;
    width: 200px;
    border: 1px solid orange;
}
_x000D_
<div class="container">
    <div class="helper">
        <div class="content">
            <p>stuff</p>
        </div>
    </div>
</div
_x000D_
_x000D_
_x000D_

JSFiddle works fine according to Browsershot.

Print a list in reverse order with range()?

Using without [::-1] or reversed -

def reverse(text):
    result = []
    for index in range(len(text)-1,-1,-1):
        c = text[index]
        result.append(c)
    return ''.join(result)

print reverse("python!")

How do I use NSTimer?

NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:60 target:self selector:@selector(timerCalled) userInfo:nil repeats:NO];

-(void)timerCalled
{
     NSLog(@"Timer Called");
     // Your Code
}

PLS-00103: Encountered the symbol "CREATE"

At line 5 there is a / missing.

There is a good answer on the differences between ; and / here.

Basically, when running a CREATE block via script, you need to use / to let SQLPlus know when the block ends, since a PL/SQL block can contain many instances of ;.

Get key from a HashMap using the value

You mixed the keys and the values.

Hashmap <Integer,String> hashmap = new HashMap<Integer, String>();

hashmap.put(100, "one");
hashmap.put(200, "two");

Afterwards a

hashmap.get(100);

will give you "one"

String comparison in Python: is vs. ==

For all built-in Python objects (like strings, lists, dicts, functions, etc.), if x is y, then x==y is also True.

Not always. NaN is a counterexample. But usually, identity (is) implies equality (==). The converse is not true: Two distinct objects can have the same value.

Also, is it generally considered better to just use '==' by default, even when comparing int or Boolean values?

You use == when comparing values and is when comparing identities.

When comparing ints (or immutable types in general), you pretty much always want the former. There's an optimization that allows small integers to be compared with is, but don't rely on it.

For boolean values, you shouldn't be doing comparisons at all. Instead of:

if x == True:
    # do something

write:

if x:
    # do something

For comparing against None, is None is preferred over == None.

I've always liked to use 'is' because I find it more aesthetically pleasing and pythonic (which is how I fell into this trap...), but I wonder if it's intended to just be reserved for when you care about finding two objects with the same id.

Yes, that's exactly what it's for.

How to add chmod permissions to file in Git?

According to official documentation, you can set or remove the "executable" flag on any tracked file using update-index sub-command.

To set the flag, use following command:

git update-index --chmod=+x path/to/file

To remove it, use:

git update-index --chmod=-x path/to/file

Under the hood

While this looks like the regular unix files permission system, actually it is not. Git maintains a special "mode" for each file in its internal storage:

  • 100644 for regular files
  • 100755 for executable ones

You can visualize it using ls-file subcommand, with --stage option:

$ git ls-files --stage
100644 aee89ef43dc3b0ec6a7c6228f742377692b50484 0       .gitignore
100755 0ac339497485f7cc80d988561807906b2fd56172 0       my_executable_script.sh

By default, when you add a file to a repository, Git will try to honor its filesystem attributes and set the correct filemode accordingly. You can disable this by setting core.fileMode option to false:

git config core.fileMode false

Troubleshooting

If at some point the Git filemode is not set but the file has correct filesystem flag, try to remove mode and set it again:

git update-index --chmod=-x path/to/file
git update-index --chmod=+x path/to/file

Bonus

Starting with Git 2.9, you can stage a file AND set the flag in one command:

git add --chmod=+x path/to/file

React JS - Uncaught TypeError: this.props.data.map is not a function

More generally, you can also convert the new data into an array and use something like concat:

var newData = this.state.data.concat([data]);  
this.setState({data: newData})

This pattern is actually used in Facebook's ToDo demo app (see the section "An Application") at https://facebook.github.io/react/.

Confirm button before running deleting routine from website

You could use JavaScript. Either put the code inline, into a function or use jQuery.

  1. Inline:

    <a href="deletelink" onclick="return confirm('Are you sure?')">Delete</a>
    
  2. In a function:

    <a href="deletelink" onclick="return checkDelete()">Delete</a>
    

    and then put this in <head>:

    <script language="JavaScript" type="text/javascript">
    function checkDelete(){
        return confirm('Are you sure?');
    }
    </script>
    

    This one has more work, but less file size if the list is long.

  3. With jQuery:

    <a href="deletelink" class="delete">Delete</a>
    

    And put this in <head>:

    <script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
    <script language="JavaScript" type="text/javascript">
    $(document).ready(function(){
        $("a.delete").click(function(e){
            if(!confirm('Are you sure?')){
                e.preventDefault();
                return false;
            }
            return true;
        });
    });
    </script>
    

dataframe: how to groupBy/count then filter on count in Scala

When you pass a string to the filter function, the string is interpreted as SQL. Count is a SQL keyword and using count as a variable confuses the parser. This is a small bug (you can file a JIRA ticket if you want to).

You can easily avoid this by using a column expression instead of a String:

df.groupBy("x").count()
  .filter($"count" >= 2)
  .show()

Specifying a custom DateTime format when serializing with Json.Net

It can also be done with an IsoDateTimeConverter instance, without changing global formatting settings:

string json = JsonConvert.SerializeObject(yourObject,
    new IsoDateTimeConverter() { DateTimeFormat = "yyyy-MM-dd HH:mm:ss" });

This uses the JsonConvert.SerializeObject overload that takes a params JsonConverter[] argument.

Hbase quickly count number of rows

U can find sample example here:

/**
     * Used to get the number of rows of the table
     * @param tableName
     * @param familyNames
     * @return the number of rows
     * @throws IOException
     */
    public long countRows(String tableName, String... familyNames) throws IOException {
        long rowCount = 0;
        Configuration configuration = connection.getConfiguration();
        // Increase RPC timeout, in case of a slow computation
        configuration.setLong("hbase.rpc.timeout", 600000);
        // Default is 1, set to a higher value for faster scanner.next(..)
        configuration.setLong("hbase.client.scanner.caching", 1000);

        AggregationClient aggregationClient = new AggregationClient(configuration);
        try {
            Scan scan = new Scan();
            if (familyNames != null && familyNames.length > 0) {
                for (String familyName : familyNames) {
                    scan.addFamily(Bytes.toBytes(familyName));
                }
            }
            rowCount = aggregationClient.rowCount(TableName.valueOf(tableName), new LongColumnInterpreter(), scan);
        } catch (Throwable e) {
            throw new IOException(e);
        }
        return rowCount;
    }

Cannot import keras after installation

Ran to the same issue, Assuming your using anaconda3 and your using a venv with >= python=3.6:

python -m pip install keras
sudo python -m pip install --user tensorflow

Access nested dictionary items via a list of keys?

An alternative way if you don't want to raise errors if one of the keys is absent (so that your main code can run without interruption):

def get_value(self,your_dict,*keys):
    curr_dict_ = your_dict
    for k in keys:
        v = curr_dict.get(k,None)
        if v is None:
            break
        if isinstance(v,dict):
            curr_dict = v
    return v

In this case, if any of the input keys is not present, None is returned, which can be used as a check in your main code to perform an alternative task.

How do I find all the files that were created today in Unix/Linux?

You can use find and ls to accomplish with this:

find . -type f -exec ls -l {} \; |  egrep "Aug 26";

It will find all files in this directory, display useful informations (-l) and filter the lines with some date you want... It may be a little bit slow, but still useful in some cases.

Is there any 'out-of-the-box' 2D/3D plotting library for C++?

I programmatically provide required input files to GNUPlot executable and invoke it using system() function. It is suitable to my situation since I only want to visualize my data during research. But if you want the plotting functionality integrated into your executable file, maybe this is not for you :)

Get first letter of a string from column

.str.get

This is the simplest to specify string methods

# Setup
df = pd.DataFrame({'A': ['xyz', 'abc', 'foobar'], 'B': [123, 456, 789]})
df

        A    B
0     xyz  123
1     abc  456
2  foobar  789

df.dtypes

A    object
B     int64
dtype: object

For string (read:object) type columns, use

df['C'] = df['A'].str[0]
# Similar to,
df['C'] = df['A'].str.get(0)

.str handles NaNs by returning NaN as the output.

For non-numeric columns, an .astype conversion is required beforehand, as shown in @Ed Chum's answer.

# Note that this won't work well if the data has NaNs. 
# It'll return lowercase "n"
df['D'] = df['B'].astype(str).str[0]

df
        A    B  C  D
0     xyz  123  x  1
1     abc  456  a  4
2  foobar  789  f  7

List Comprehension and Indexing

There is enough evidence to suggest a simple list comprehension will work well here and probably be faster.

# For string columns
df['C'] = [x[0] for x in df['A']]

# For numeric columns
df['D'] = [str(x)[0] for x in df['B']]

df
        A    B  C  D
0     xyz  123  x  1
1     abc  456  a  4
2  foobar  789  f  7

If your data has NaNs, then you will need to handle this appropriately with an if/else in the list comprehension,

df2 = pd.DataFrame({'A': ['xyz', np.nan, 'foobar'], 'B': [123, 456, np.nan]})
df2

        A      B
0     xyz  123.0
1     NaN  456.0
2  foobar    NaN

# For string columns
df2['C'] = [x[0] if isinstance(x, str) else np.nan for x in df2['A']]

# For numeric columns
df2['D'] = [str(x)[0] if pd.notna(x) else np.nan for x in df2['B']]

        A      B    C    D
0     xyz  123.0    x    1
1     NaN  456.0  NaN    4
2  foobar    NaN    f  NaN

Let's do some timeit tests on some larger data.

df_ = df.copy()
df = pd.concat([df_] * 5000, ignore_index=True) 

%timeit df.assign(C=df['A'].str[0])
%timeit df.assign(D=df['B'].astype(str).str[0])

%timeit df.assign(C=[x[0] for x in df['A']])
%timeit df.assign(D=[str(x)[0] for x in df['B']])

12 ms ± 253 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
27.1 ms ± 1.38 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

3.77 ms ± 110 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
7.84 ms ± 145 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

List comprehensions are 4x faster.

What does Html.HiddenFor do?

The Use of Razor code @Html.Hidden or @Html.HiddenFor is similar to the following Html code

 <input type="hidden"/>

And also refer the following link

https://msdn.microsoft.com/en-us/library/system.web.mvc.html.inputextensions.hiddenfor(v=vs.118).aspx

TypeScript and field initializers

if you want to create new instance without set initial value when instance

1- you have to use class not interface

2- you have to set initial value when create class

export class IStudentDTO {
 Id:        number = 0;
 Name:      string = '';


student: IStudentDTO = new IStudentDTO();

My Routes are Returning a 404, How can I Fix Them?

  1. setup .env file
  2. configure index.html
  3. make sure u have .htaccess
  4. sudo service apache2 restart

most probably it's due to cache problems

How do you use String.substringWithRange? (or, how do Ranges work in Swift?)

Simple extension for String:

extension String {

    func substringToIndex(index: Int) -> String {
        return self[startIndex...startIndex.advancedBy(min(index, characters.count - 1))]
    }
}

What is a simple command line program or script to backup SQL server databases?

I use ExpressMaint.

To backup all user databases I do for example:

C:\>ExpressMaint.exe -S (local)\sqlexpress -D ALL_USER -T DB -BU HOURS -BV 1 -B c:\backupdir\ -DS

Argument of type 'X' is not assignable to parameter of type 'X'

Also adding other Scenarios where you may see these Errors

  1. First Check you compiler version, Download latest Typescript compiler to support ES6 syntaxes

  2. typescript still produces output even with typing errors this doesn't actually block development,

When you see these errors Check for Syntaxes in initialization or when Calling these methods or variables,
Check whether the parameters of the functions are of wrong data Type,you initialized as 'string' and assigning a 'boolean' or 'number'

For Example

1.

 private errors: string;
    //somewhere in code you assign a boolean value to (string)'errors'
    this.errors=true
    or 
    this.error=5

2.

 private values: Array<number>;    
    this.values.push(value);  //Argument of type 'X' is not assignable to parameter of type 'X'

The Error message here is because the Square brackets for Array Initialization is missing, It works even without it, but VS Code red alerts.

private values: Array<number> = [];    
this.values.push(value);

Note:
Remember that Javascript typecasts according to the value assigned, So typescript notifies them but the code executes even with these errors highlighted in VS Code

Ex:

 var a=2;
 typeof(a) // "number"
 var a='Ignatius';
 typeof(a) // "string"

In SQL, how can you "group by" in ranges?

An alternative approach would involve storing the ranges in a table, instead of embedding them in the query. You would end up with a table, call it Ranges, that looks like this:

LowerLimit   UpperLimit   Range 
0              9          '0-9'
10            19          '10-19'
20            29          '20-29'
30            39          '30-39'

And a query that looks like this:

Select
   Range as [Score Range],
   Count(*) as [Number of Occurences]
from
   Ranges r inner join Scores s on s.Score between r.LowerLimit and r.UpperLimit
group by Range

This does mean setting up a table, but it would be easy to maintain when the desired ranges change. No code changes necessary!

Java Desktop application: SWT vs. Swing

I would use Swing for a couple of reasons.

  • It has been around longer and has had more development effort applied to it. Hence it is likely more feature complete and (maybe) has fewer bugs.

  • There is lots of documentation and other guidance on producing performant applications.

  • It seems like changes to Swing propagate to all platforms simultaneously while changes to SWT seem to appear on Windows first, then Linux.

If you want to build a very feature-rich application, you might want to check out the NetBeans RCP (Rich Client Platform). There's a learning curve, but you can put together nice applications quickly with a little practice. I don't have enough experience with the Eclipse platform to make a valid judgment.

If you don't want to use the entire RCP, NetBeans also has many useful components that can be pulled out and used independently.

One other word of advice, look into different layout managers. They tripped me up for a long time when I was learning. Some of the best aren't even in the standard library. The MigLayout (for both Swing and SWT) and JGoodies Forms tools are two of the best in my opinion.

Converting a byte array to PNG/JPG

There are two problems with this question:

Assuming you have a gray scale bitmap, you have two factors to consider:

  1. For JPGS... what loss of quality is tolerable?
  2. For pngs... what level of compression is tolerable? (Although for most things I've seen, you don't have that much of a choice, so this choice might be negligible.) For anybody thinking this question doesn't make sense: yes, you can change the amount of compression/number of passes attempted to compress; check out either Ifranview or some of it's plugins.

Answer those questions, and then you might be able to find your original answer.

Add disabled attribute to input element using Javascript

Working code from my sources:

HTML WORLD

<select name="select_from" disabled>...</select>

JS WORLD

var from = jQuery('select[name=select_from]');

//add disabled
from.attr('disabled', 'disabled');



//remove it
from.removeAttr("disabled");

JavaScript: IIF like statement

If your end goal is to add elements to your page, just manipulate the DOM directly. Don't use string concatenation to try to create HTML - what a pain! See how much more straightforward it is to just create your element, instead of the HTML that represents your element:

var x = document.createElement("option");
x.value = col;
x.text = "Very roomy";
x.selected = col == "screwdriver";

Then, later when you put the element in your page, instead of setting the innerHTML of the parent element, call appendChild():

mySelectElement.appendChild(x);

How to determine the IP address of a Solaris system

If you're a normal user (i.e., not 'root') ifconfig isn't in your path, but it's the command you want.

More specifically: /usr/sbin/ifconfig -a

How do I convert hh:mm:ss.000 to milliseconds in Excel?

Rather than doing string manipulation, you can use the HOUR, MINUTE, SECOND functions to break apart the time. You can then multiply by 60*60*1000, 60*1000, and 1000 respectively to get milliseconds.

Read/write files within a Linux kernel module

You should be aware that you should avoid file I/O from within Linux kernel when possible. The main idea is to go "one level deeper" and call VFS level functions instead of the syscall handler directly:

Includes:

#include <linux/fs.h>
#include <asm/segment.h>
#include <asm/uaccess.h>
#include <linux/buffer_head.h>

Opening a file (similar to open):

struct file *file_open(const char *path, int flags, int rights) 
{
    struct file *filp = NULL;
    mm_segment_t oldfs;
    int err = 0;

    oldfs = get_fs();
    set_fs(get_ds());
    filp = filp_open(path, flags, rights);
    set_fs(oldfs);
    if (IS_ERR(filp)) {
        err = PTR_ERR(filp);
        return NULL;
    }
    return filp;
}

Close a file (similar to close):

void file_close(struct file *file) 
{
    filp_close(file, NULL);
}

Reading data from a file (similar to pread):

int file_read(struct file *file, unsigned long long offset, unsigned char *data, unsigned int size) 
{
    mm_segment_t oldfs;
    int ret;

    oldfs = get_fs();
    set_fs(get_ds());

    ret = vfs_read(file, data, size, &offset);

    set_fs(oldfs);
    return ret;
}   

Writing data to a file (similar to pwrite):

int file_write(struct file *file, unsigned long long offset, unsigned char *data, unsigned int size) 
{
    mm_segment_t oldfs;
    int ret;

    oldfs = get_fs();
    set_fs(get_ds());

    ret = vfs_write(file, data, size, &offset);

    set_fs(oldfs);
    return ret;
}

Syncing changes a file (similar to fsync):

int file_sync(struct file *file) 
{
    vfs_fsync(file, 0);
    return 0;
}

[Edit] Originally, I proposed using file_fsync, which is gone in newer kernel versions. Thanks to the poor guy suggesting the change, but whose change was rejected. The edit was rejected before I could review it.

how to set font size based on container size?

Another js alternative:

Working Example

fontsize = function () {
    var fontSize = $("#container").width() * 0.10; // 10% of container width
    $("#container h1").css('font-size', fontSize);
};
$(window).resize(fontsize);
$(document).ready(fontsize);

Or as stated in torazaburo's answer you could use svg. I put together a simple example as a proof of concept:

SVG Example

<div id="container">
    <svg width="100%" height="100%" viewBox="0 0 13 15">
        <text x="0" y="13">X</text>
    </svg>
</div>

Python: Remove division decimal

if val % 1 == 0:
    val = int(val)

else:
    val = float(val)

This worked for me.

How it works: if the remainder of the quotient of val and 1 is 0, val has to be an integer and can, therefore, be declared to be int without having to worry about losing decimal numbers.

Compare these two situations:

A:

val = 12.00

if val % 1 == 0:
    val = int(val)
else:
    val = float(val)

print(val)

In this scenario, the output is 12, because 12.00 divided by 1 has the remainder of 0. With this information we know, that val doesn't have any decimals and we can declare val to be int.

B:

val = 13.58

if val % 1 == 0:
    val = int(val)
else:
    val = float(val)

print(val)

This time the output is 13.58, because when val is divided by 1 there is a remainder (0.58) and therefore val is declared to be a float.

By just declaring the number to be an int (without testing the remainder) decimal numbers will be cut off.

This way there are no zeros in the end and no other than the zeros will be ignored.

How to count duplicate value in an array in javascript

Single line based on reduce array function

_x000D_
_x000D_
const uniqueCount =  ["a", "b", "c", "d", "d", "e", "a", "b", "c", "f", "g", "h", "h", "h", "e", "a"];
const distribution = uniqueCount.reduce((acum,cur) => Object.assign(acum,{[cur]: (acum[cur] || 0)+1}),{});
console.log(JSON.stringify(distribution,null,2));
_x000D_
_x000D_
_x000D_

How to set default value for form field in Symfony2?

If you set 'data' in your creation form, this value will be not modified when edit your entity.

My solution is :

public function buildForm(FormBuilderInterface $builder, array $options) {
    // In my example, data is an associated array
    $data = $builder->getData();

    $builder->add('myfield', 'text', array(
     'label' => 'Field',
     'data' => array_key_exits('myfield', $data) ? $data['myfield'] : 'Default value',
    ));
}

Bye.

Full Page <iframe>

This is what I have used in the past.

html, body {
  height: 100%;
  overflow: auto;
}

Also in the iframe add the following style

border: 0; position:fixed; top:0; left:0; right:0; bottom:0; width:100%; height:100%

Highcharts - redraw() vs. new Highcharts.chart

chart.series[0].setData(data,true);

The setData method itself will call the redraw method

Unit testing click event in Angular

Events can be tested using the async/fakeAsync functions provided by '@angular/core/testing', since any event in the browser is asynchronous and pushed to the event loop/queue.

Below is a very basic example to test the click event using fakeAsync.

The fakeAsync function enables a linear coding style by running the test body in a special fakeAsync test zone.

Here I am testing a method that is invoked by the click event.

it('should', fakeAsync( () => {
    fixture.detectChanges();
    spyOn(componentInstance, 'method name'); //method attached to the click.
    let btn = fixture.debugElement.query(By.css('button'));
    btn.triggerEventHandler('click', null);
    tick(); // simulates the passage of time until all pending asynchronous activities finish
    fixture.detectChanges();
    expect(componentInstance.methodName).toHaveBeenCalled();
}));

Below is what Angular docs have to say:

The principle advantage of fakeAsync over async is that the test appears to be synchronous. There is no then(...) to disrupt the visible flow of control. The promise-returning fixture.whenStable is gone, replaced by tick()

There are limitations. For example, you cannot make an XHR call from within a fakeAsync

Convert R vector to string vector of 1 element

Use the collapse argument to paste:

paste(a,collapse=" ")
[1] "aa bb cc"

How do DATETIME values work in SQLite?

For practically all date and time matters I prefer to simplify things, very, very simple... Down to seconds stored in integers.

Integers will always be supported as integers in databases, flat files, etc. You do a little math and cast it into another type and you can format the date anyway you want.

Doing it this way, you don't have to worry when [insert current favorite database here] is replaced with [future favorite database] which coincidentally didn't use the date format you chose today.

It's just a little math overhead (eg. methods--takes two seconds, I'll post a gist if necessary) and simplifies things for a lot of operations regarding date/time later.

How do you specifically order ggplot2 x axis instead of alphabetical order?

It is a little difficult to answer your specific question without a full, reproducible example. However something like this should work:

#Turn your 'treatment' column into a character vector
data$Treatment <- as.character(data$Treatment)
#Then turn it back into a factor with the levels in the correct order
data$Treatment <- factor(data$Treatment, levels=unique(data$Treatment))

In this example, the order of the factor will be the same as in the data.csv file.

If you prefer a different order, you can order them by hand:

data$Treatment <- factor(data$Treatment, levels=c("Y", "X", "Z"))

However this is dangerous if you have a lot of levels: if you get any of them wrong, that will cause problems.

Remove icon/logo from action bar on android

I used this and it worked for me.

        getActionBar().setIcon(
        new ColorDrawable(getResources().getColor(android.R.color.transparent)));

Image style height and width not taken in outlook mails

The px needs to be left off, for some odd reason.

When should we use intern method of String on String literals

Learn Java String Intern - once for all

Strings in java are immutable objects by design. Therefore, two string objects even with same value will be different objects by default. However, if we wish to save memory, we could indicate to use same memory by a concept called string intern.

The below rules would help you understand the concept in clear terms:

  1. String class maintains an intern-pool which is initially empty. This pool must guarantee to contain string objects with only unique values.
  2. All string literals having same value must be considered same memory-location object because they have otherwise no notion of distinction. Therefore, all such literals with same value will make a single entry in the intern-pool and will refer to same memory location.
  3. Concatenation of two or more literals is also a literal. (Therefore rule #2 will be applicable for them)
  4. Each string created as object (i.e. by any other method except as literal) will have different memory locations and will not make any entry in the intern-pool
  5. Concatenation of literals with non-literals will make a non-literal. Thus, the resultant object will have a new memory location and will NOT make an entry in the intern-pool.
  6. Invoking intern method on a string object, either creates a new object that enters the intern-pool or return an existing object from the pool that has same value. The invocation on any object which is not in the intern-pool, does NOT move the object to the pool. It rather creates another object that enters the pool.

Example:

String s1=new String (“abc”);
String s2=new String (“abc”);
If (s1==s2)  //would return false  by rule #4
If (“abc” == “a”+”bc” )  //would return true by rules #2 and #3
If (“abc” == s1 )  //would return false  by rules #1,2 and #4
If (“abc” == s1.intern() )  //would return true  by rules #1,2,4 and #6
If ( s1 == s2.intern() )      //wound return false by rules #1,4, and #6

Note: The motivational cases for string intern are not discussed here. However, saving of memory will definitely be one of the primary objectives.

Remove ListView items in Android

int count = adapter.getCount();
for (int i = 0; i < count; i++) {
 adapter.remove(adapter.getItem(i));
}

then call notifyDataSetChanged();

Is there a job scheduler library for node.js?

I am using kue: https://github.com/learnboost/kue . It is pretty nice.

The official features and my comments:

  1. delayed jobs.
    • If you want to let the job run at a specific time, calculate the milliseconds between that time and now. Call job.delay(milliseconds) (The doc says minutes, which is wrong.) Don't forget to add "jobs.promote();" when you init jobs.
  2. job event and progress pubsub.
    • I don't understand it.
  3. rich integrated UI.
    • Very useful. You can check the job status (done, running, delayed) in integrated UI and don't need to write any code. And you can delete old records in UI.
  4. infinite scrolling
    • Sometimes not working. Have to refresh.
  5. UI progress indication
    • Good for the time-consuming jobs.
  6. job specific logging
    • Because they are delayed jobs, you should log useful info in the job and check later through UI.
  7. powered by Redis
    • Very useful. When you restart your node.js app, all job records are still there and the scheduled jobs will execute too!
  8. optional retries
    • Nice.
  9. full-text search capabilities
    • Good.
  10. RESTful JSON API
    • Sound good, but I never use it.

Edit:

  1. kue is not a cron like library.
  2. By default kue does not supports job which runs repeatedly (e.g. every Sunday).

'Microsoft.ACE.OLEDB.16.0' provider is not registered on the local machine. (System.Data)

Follow these steps:

  1. Go [here][1], download Microsoft Access Database Engine 2016 Redistributable and install
  2. Close SQL Server Management Studio
  3. Go to Start Menu -> Microsoft SQL Server 2017 -> SQL Server 2017 Import and Export Data (64-bit)
  4. Open the application and try to import data using the "Excel 2016" option, it should work fine.

ant build.xml file doesn't exist

If I understand correctly, you assumed that -v is the "print version" command. Check the documentation, that is not the case -- instead ant -v is running ant build in verbose mode. So ant is trying to perform your build, based on the build.xml file, which is obviously not there.

To answer your question explicitly: there is probably nothing wrong with both the system nor ant installation.

How to clear Facebook Sharer cache?

Use api Is there an API to force Facebook to scrape a page again?

$furl = 'https://graph.facebook.com';

$ch = curl_init();

curl_setopt( $ch, CURLOPT_URL, $furl );
curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
curl_setopt( $ch, CURLOPT_POST, true );
$params = array(
    'id' => '<update_url>',
    'scrape' => true );
$data = http_build_query( $params );
curl_setopt( $ch, CURLOPT_POSTFIELDS, $data );

curl_exec( $ch );
$httpCode = curl_getinfo( $ch, CURLINFO_HTTP_CODE );

How to remove "href" with Jquery?

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

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

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

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

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

How do I delete files programmatically on Android?

Try this one. It is working for me.

handler.postDelayed(new Runnable() {
    @Override
    public void run() {
        // Set up the projection (we only need the ID)
        String[] projection = { MediaStore.Images.Media._ID };

        // Match on the file path
        String selection = MediaStore.Images.Media.DATA + " = ?";
        String[] selectionArgs = new String[] { imageFile.getAbsolutePath() };

        // Query for the ID of the media matching the file path
        Uri queryUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        ContentResolver contentResolver = getActivity().getContentResolver();
        Cursor c = contentResolver.query(queryUri, projection, selection, selectionArgs, null);

        if (c != null) {
            if (c.moveToFirst()) {
                // We found the ID. Deleting the item via the content provider will also remove the file
                long id = c.getLong(c.getColumnIndexOrThrow(MediaStore.Images.Media._ID));
                Uri deleteUri = ContentUris.withAppendedId(queryUri, id);
                contentResolver.delete(deleteUri, null, null);
            } else {
                // File not found in media store DB
            }
            c.close();
        }
    }
}, 5000);

Getting a link to go to a specific section on another page

I believe the example you've posted is using HTML5, which allows you to jump to any DOM element with the matching ID attribute. To support older browsers, you'll need to change:

<div id="timeline" name="timeline" ...>

To the old format:

<a name="timeline" />

You'll then be able to navigate to /academics/page.html#timeline and jump right to that section.

Also, check out this similar question.

HTML forms - input type submit problem with action=URL when URL contains index.aspx

This appears to be my "preferred" solution:

<form action="www.spufalcons.com/index.aspx?tab=gymnastics&path=gym" method="post">  <div>
<input type="submit" value="Gymnastics"></div>

Sorry for the presentation format - I'm still trying to learn how to use this forum....

I do have a follow-up question. In looking at my MySQL database of URL's it appears that ~30% of the URL's will need to use this post/div wrapper approach. This leaves ~70% that cannot accept the "post" attribute. For example:

<form action="http://www.google.com" method="post">
  <div>
    <input type="submit" value="Google"/>
  </div></form>

does not work. Do you have a recommendation for how to best handle this get/post condition test. Off the top of my head I'm guessing that using PHP to evaluate the existence of the "?" character in the URL may be my best approach, although I'm not sure how to structure the HTML form to accomplish this.

Thank YOU!

Why would an Enum implement an Interface?

Here's one example (a similar/better one is found in Effective Java 2nd Edition):

public interface Operator {
    int apply (int a, int b);
}

public enum SimpleOperators implements Operator {
    PLUS { 
        int apply(int a, int b) { return a + b; }
    },
    MINUS { 
        int apply(int a, int b) { return a - b; }
    };
}

public enum ComplexOperators implements Operator {
    // can't think of an example right now :-/
}

Now to get a list of both the Simple + Complex Operators:

List<Operator> operators = new ArrayList<Operator>();

operators.addAll(Arrays.asList(SimpleOperators.values()));
operators.addAll(Arrays.asList(ComplexOperators.values()));

So here you use an interface to simulate extensible enums (which wouldn't be possible without using an interface).

How do I check to see if my array includes an object?

Arrays in Ruby don't have exists? method, but they have an include? method as described in the docs. Something like

unless @suggested_horses.include?(horse)
   @suggested_horses << horse
end

should work out of box.

Media Queries - In between two widths

You need to switch your values:

/* No greater than 900px, no less than 400px */
@media (max-width:900px) and (min-width:400px) {
    .foo {
        display:none;
    }
}?

Demo: http://jsfiddle.net/xf6gA/ (using background color, so it's easier to confirm)

How to escape single quotes in MySQL

In PHP, use mysqli_real_escape_string.

Example from the PHP Manual:

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City");

$city = "'s Hertogenbosch";

/* this query will fail, cause we didn't escape $city */
if (!mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
    printf("Error: %s\n", mysqli_sqlstate($link));
}

$city = mysqli_real_escape_string($link, $city);

/* this query with escaped $city will work */
if (mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
    printf("%d Row inserted.\n", mysqli_affected_rows($link));
}

mysqli_close($link);
?>

Container is running beyond memory limits

While working with spark in EMR I was having the same problem and setting maximizeResourceAllocation=true did the trick; hope it helps someone. You have to set it when you create the cluster. From the EMR docs:

aws emr create-cluster --release-label emr-5.4.0 --applications Name=Spark \
--instance-type m3.xlarge --instance-count 2 --service-role EMR_DefaultRole --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole --configurations https://s3.amazonaws.com/mybucket/myfolder/myConfig.json

Where myConfig.json should say:

[
  {
    "Classification": "spark",
    "Properties": {
      "maximizeResourceAllocation": "true"
    }
  }
]

How to remove an iOS app from the App Store

For permanently delete your app follow below steps.

Step 1 :- GO to My Apps App in iTunes Connect

enter image description here

Here you can see your all app which are currently on Appstore.

Step 2 :- Select your app which you want to delete.(click on app-name)

enter image description here

Step 3 :- Select Pricing and Availability Tab.

enter image description here

Step 4 :- Select Remove from sale option.

enter image description here

Step 5 :- Click on save Button.

Now you will see below your app like , Developer Removed it from sale in Red Symbol in place of Green.

enter image description here

Step 6 :- Now again Select your app and Go to App information Tab. you will see Delete App option. (need to scroll bit bottom)

enter image description here

Step 7 :- After clicking on Delete button you will get warning like this ,

enter image description here

Step 8 :- Click on Delete button.

Congratulation , You have Permanently deleted your app successfully from appstore. Now , you cant able to see app on appstore aswellas in your developer account.

Note :-

When you have selected only Remove from sale option you have not deleted app permanently. You can able to make your app live again by clicking on Available in all territories option Again.

enter image description here

Get all photos from Instagram which have a specific hashtag with PHP

Here's another example I wrote a while ago:

<?php       
    // Get class for Instagram
    // More examples here: https://github.com/cosenary/Instagram-PHP-API
    require_once 'instagram.class.php';

    // Initialize class with client_id
    // Register at http://instagram.com/developer/ and replace client_id with your own
    $instagram = new Instagram('CLIENT_ID_HERE');

    // Set keyword for #hashtag
    $tag = 'KEYWORD HERE';

    // Get latest photos according to #hashtag keyword
    $media = $instagram->getTagMedia($tag);

    // Set number of photos to show
    $limit = 5;

    // Set height and width for photos
    $size = '100';

    // Show results
    // Using for loop will cause error if there are less photos than the limit
    foreach(array_slice($media->data, 0, $limit) as $data)
    {
        // Show photo
        echo '<p><img src="'.$data->images->thumbnail->url.'" height="'.$size.'" width="'.$size.'" alt="SOME TEXT HERE"></p>';
    }
?>

Screen width in React Native

If you have a Style component that you can require from your Component, then you could have something like this at the top of the file:

const Dimensions = require('Dimensions');

const window = Dimensions.get('window');

And then you could provide fulscreen: {width: window.width, height: window.height}, in your Style component. Hope this helps

How to get the title of HTML page with JavaScript?

Put in the URL bar and then click enter:

javascript:alert(document.title);

You can select and copy the text from the alert depending on the website and the web browser you are using.

How Does Modulus Divison Work

The result of a modulo division is the remainder of an integer division of the given numbers.

That means:

27 / 16 = 1, remainder 11
=> 27 mod 16 = 11

Other examples:

30 / 3 = 10, remainder 0
=> 30 mod 3 = 0

35 / 3 = 11, remainder 2
=> 35 mod 3 = 2

Converting Chart.js canvas chart to image using .toDataUrl() results in blank image

The chart seem to be async so you will probably need to provide a callback when the animation has finished or else the canvas will be empty.

var options = {
    bezierCurve : false,
    onAnimationComplete: done  /// calls function done() {} at end
};

Android device chooser - My device seems offline

I'm on OSX and have a macbook retina. Switching the USB port that my device was plugged into, for some reason, fixed my issue.

Why can't static methods be abstract in Java?

First, a key point about abstract classes - An abstract class cannot be instantiated (see wiki). So, you can't create any instance of an abstract class.

Now, the way java deals with static methods is by sharing the method with all the instances of that class.

So, If you can't instantiate a class, that class can't have abstract static methods since an abstract method begs to be extended.

Boom.

how to format date in Component of angular 5

Another option can be using built in angular formatDate function. I am assuming that you are using reactive forms. Here todoDate is a date input field in template.

import {formatDate} from '@angular/common';

this.todoForm.controls.todoDate.setValue(formatDate(this.todo.targetDate, 'yyyy-MM-dd', 'en-US'));

Why does Java have transient fields?

Serialization systems other than the native java one can also use this modifier. Hibernate, for instance, will not persist fields marked with either @Transient or the transient modifier. Terracotta as well respects this modifier.

I believe the figurative meaning of the modifier is "this field is for in-memory use only. don't persist or move it outside of this particular VM in any way. Its non-portable". i.e. you can't rely on its value in another VM memory space. Much like volatile means you can't rely on certain memory and thread semantics.

Using RegEx in SQL Server

SELECT * from SOME_TABLE where NAME like '%[^A-Z]%'

Or some other expression instead of A-Z

How to use (install) dblink in PostgreSQL?

On linux, find dblink.sql, then execute in the postgresql console something like this to create all required functions:

\i /usr/share/postgresql/8.4/contrib/dblink.sql 

you might need to install the contrib packages: sudo apt-get install postgresql-contrib

LD_LIBRARY_PATH vs LIBRARY_PATH

LIBRARY_PATH is used by gcc before compilation to search directories containing static and shared libraries that need to be linked to your program.

LD_LIBRARY_PATH is used by your program to search directories containing shared libraries after it has been successfully compiled and linked.

EDIT: As pointed below, your libraries can be static or shared. If it is static then the code is copied over into your program and you don't need to search for the library after your program is compiled and linked. If your library is shared then it needs to be dynamically linked to your program and that's when LD_LIBRARY_PATH comes into play.

How to use goto statement correctly

The Java keyword list specifies the goto keyword, but it is marked as "not used".

This was probably done in case it were to be added to a later version of Java.

If goto weren't on the list, and it were added to the language later on, existing code that used the word goto as an identifier (variable name, method name, etcetera) would break. But because goto is a keyword, such code will not even compile in the present, and it remains possible to make it actually do something later on, without breaking existing code.