Programs & Examples On #Mount point

docker mounting volumes on host

Let me add my own answer, because I believe the others are missing the point of Docker.

Using VOLUME in the Dockerfile is the Right Way™, because you let Docker know that a certain directory contains permanent data. Docker will create a volume for that data and never delete it, even if you remove all the containers that use it.

It also bypasses the union file system, so that the volume is in fact an actual directory that gets mounted (read-write or readonly) in the right place in all the containers that share it.

Now, in order to access that data from the host, you only need to inspect your container:

# docker inspect myapp
[{
    .
    .
    .
    "Volumes": {
        "/var/www": "/var/lib/docker/vfs/dir/b3ef4bc28fb39034dd7a3aab00e086e6...",
        "/var/cache/nginx": "/var/lib/docker/vfs/dir/62499e6b31cb3f7f59bf00d8a16b48d2...",
        "/var/log/nginx": "/var/lib/docker/vfs/dir/71896ce364ef919592f4e99c6e22ce87..."
    },
    "VolumesRW": {
        "/var/www": false,
        "/var/cache/nginx": true,
        "/var/log/nginx": true
    }
}]

What I usually do is make symlinks in some standard place such as /srv, so that I can easily access the volumes and manage the data they contain (only for the volumes you care about):

ln -s /var/lib/docker/vfs/dir/b3ef4bc28fb39034dd7a3aab00e086e6... /srv/myapp-www
ln -s /var/lib/docker/vfs/dir/71896ce364ef919592f4e99c6e22ce87... /srv/myapp-log

Difference between getContext() , getApplicationContext() , getBaseContext() and "this"

getApplicationContext() - Returns the context for all activities running in application.

getBaseContext() - If you want to access Context from another context within application you can access.

getContext() - Returns the context view only current running activity.

What is the difference between Hibernate and Spring Data JPA

Hibernate is implementation of "JPA" which is a specification for Java objects in Database.

I would recommend to use w.r.t JPA as you can switch between different ORMS.

When you use JDBC then you need to use SQL Queries, so if you are proficient in SQL then go for JDBC.

Get cart item name, quantity all details woocommerce

you can get the product name like this

foreach ( $cart_object->cart_contents as  $value ) {
        $_product     = apply_filters( 'woocommerce_cart_item_product', $value['data'] );

        if ( ! $_product->is_visible() ) {
                echo $_product->get_title();
        } else {
                echo $_product->get_title();
        }


     }

Java String.split() Regex

You could also do something like:

String str = "a + b - c * d / e < f > g >= h <= i == j";
String[] arr = str.split("(?<=\\G(\\w+(?!\\w+)|==|<=|>=|\\+|/|\\*|-|(<|>)(?!=)))\\s*");

It handles white spaces and words of variable length and produces the array:

[a, +, b, -, c, *, d, /, e, <, f, >, g, >=, h, <=, i, ==, j]

Integer expression expected error in shell script

You can use this syntax:

#!/bin/bash

echo " Write in your age: "
read age

if [[ "$age" -le 7 || "$age" -ge 65 ]] ; then
    echo " You can walk in for free "
elif [[ "$age" -gt 7 && "$age" -lt 65 ]] ; then
    echo " You have to pay for ticket "
fi

When to use window.opener / window.parent / window.top

  • window.opener refers to the window that called window.open( ... ) to open the window from which it's called
  • window.parent refers to the parent of a window in a <frame> or <iframe>
  • window.top refers to the top-most window from a window nested in one or more layers of <iframe> sub-windows

Those will be null (or maybe undefined) when they're not relevant to the referring window's situation. ("Referring window" means the window in whose context the JavaScript code is run.)

Changes in import statement python3

Added another case to Michal Górny's answer:

Note that relative imports are based on the name of the current module. Since the name of the main module is always "__main__", modules intended for use as the main module of a Python application must always use absolute imports.

SQL Add foreign key to existing column

ALTER TABLE Faculty 
WITH CHECK ADD  CONSTRAINT FKFacultyBook
FOREIGN KEY FacId
REFERENCES Book Book_Id

ALTER TABLE Faculty 
WITH CHECK ADD  CONSTRAINT FKFacultyStudent 
FOREIGN KEY FacId
REFERENCES Student StuId

How can I get the intersection, union, and subset of arrays in Ruby?

Utilizing the fact that you can do set operations on arrays by doing &(intersection), -(difference), and |(union).

Obviously I didn't implement the MultiSet to spec, but this should get you started:

class MultiSet
  attr_accessor :set
  def initialize(set)
    @set = set
  end
  # intersection
  def &(other)
    @set & other.set
  end
  # difference
  def -(other)
    @set - other.set
  end
  # union
  def |(other)
    @set | other.set
  end
end

x = MultiSet.new([1,1,2,2,3,4,5,6])
y = MultiSet.new([1,3,5,6])

p x - y # [2,2,4]
p x & y # [1,3,5,6]
p x | y # [1,2,3,4,5,6]

How to check the version before installing a package using apt-get?

Also, according to the man page:

apt-cache showpkg <package_name>

can also be used to:

...display information about the packages listed on the command line. Remaining arguments are package names. The available versions and reverse dependencies of each package listed are listed, as well as forward dependencies for each version. Forward (normal) dependencies are those packages upon which the package in question depends; reverse dependencies are those packages that depend upon the package in question. Thus, forward dependencies must be satisfied for a package, but reverse dependencies need not be.

Ex:

apt-cache policy conky

conky:
  Installed: (none)
  Candidate: 1.10.3-1
  Version table:
     1.10.3-1 500
        500 http://us.archive.ubuntu.com/ubuntu yakkety/universe amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu yakkety/universe i386 Packages

Using LINQ to remove elements from a List<T>

Well, it would be easier to exclude them in the first place:

authorsList = authorsList.Where(x => x.FirstName != "Bob").ToList();

However, that would just change the value of authorsList instead of removing the authors from the previous collection. Alternatively, you can use RemoveAll:

authorsList.RemoveAll(x => x.FirstName == "Bob");

If you really need to do it based on another collection, I'd use a HashSet, RemoveAll and Contains:

var setToRemove = new HashSet<Author>(authors);
authorsList.RemoveAll(x => setToRemove.Contains(x));

Python - How do you run a .py file?

Since you seem to be on windows you can do this so python <filename.py>. Check that python's bin folder is in your PATH, or you can do c:\python23\bin\python <filename.py>. Python is an interpretive language and so you need the interpretor to run your file, much like you need java runtime to run a jar file.

Post-increment and pre-increment within a 'for' loop produce same output

The result of your code will be the same. The reason is that the two incrementation operations can be seen as two distinct function calls. Both functions cause an incrementation of the variable, and only their return values are different. In this case, the return value is just thrown away, which means that there's no distinguishable difference in the output.

However, under the hood there's a difference: The post-incrementation i++ needs to create a temporary variable to store the original value of i, then performs the incrementation and returns the temporary variable. The pre-incrementation ++i doesn't create a temporary variable. Sure, any decent optimization setting should be able to optimize this away when the object is something simple like an int, but remember that the ++-operators are overloaded in more complicated classes like iterators. Since the two overloaded methods might have different operations (one might want to output "Hey, I'm pre-incremented!" to stdout for example) the compiler can't tell whether the methods are equivalent when the return value isn't used (basically because such a compiler would solve the unsolvable halting problem), it needs to use the more expensive post-incrementation version if you write myiterator++.

Three reasons why you should pre-increment:

  1. You won't have to think about whether the variable/object might have an overloaded post-incrementation method (for example in a template function) and treat it differently (or forget to treat it differently).
  2. Consistent code looks better.
  3. When someone asks you "Why do you pre-increment?" you'll get the chance to teach them about the halting problem and theoretical limits of compiler optimization. :)

numpy division with RuntimeWarning: invalid value encountered in double_scalars

You can't solve it. Simply answer1.sum()==0, and you can't perform a division by zero.

This happens because answer1 is the exponential of 2 very large, negative numbers, so that the result is rounded to zero.

nan is returned in this case because of the division by zero.

Now to solve your problem you could:

  • go for a library for high-precision mathematics, like mpmath. But that's less fun.
  • as an alternative to a bigger weapon, do some math manipulation, as detailed below.
  • go for a tailored scipy/numpy function that does exactly what you want! Check out @Warren Weckesser answer.

Here I explain how to do some math manipulation that helps on this problem. We have that for the numerator:

exp(-x)+exp(-y) = exp(log(exp(-x)+exp(-y)))
                = exp(log(exp(-x)*[1+exp(-y+x)]))
                = exp(log(exp(-x) + log(1+exp(-y+x)))
                = exp(-x + log(1+exp(-y+x)))

where above x=3* 1089 and y=3* 1093. Now, the argument of this exponential is

-x + log(1+exp(-y+x)) = -x + 6.1441934777474324e-06

For the denominator you could proceed similarly but obtain that log(1+exp(-z+k)) is already rounded to 0, so that the argument of the exponential function at the denominator is simply rounded to -z=-3000. You then have that your result is

exp(-x + log(1+exp(-y+x)))/exp(-z) = exp(-x+z+log(1+exp(-y+x)) 
                                   = exp(-266.99999385580668)

which is already extremely close to the result that you would get if you were to keep only the 2 leading terms (i.e. the first number 1089 in the numerator and the first number 1000 at the denominator):

exp(3*(1089-1000))=exp(-267)

For the sake of it, let's see how close we are from the solution of Wolfram alpha (link):

Log[(exp[-3*1089]+exp[-3*1093])/([exp[-3*1000]+exp[-3*4443])] -> -266.999993855806522267194565420933791813296828742310997510523

The difference between this number and the exponent above is +1.7053025658242404e-13, so the approximation we made at the denominator was fine.

The final result is

'exp(-266.99999385580668) = 1.1050349147204485e-116

From wolfram alpha is (link)

1.105034914720621496.. × 10^-116 # Wolfram alpha.

and again, it is safe to use numpy here too.

MySQL - length() vs char_length()

varchar(10) will store 10 characters, which may be more than 10 bytes. In indexes, it will allocate the maximium length of the field - so if you are using UTF8-mb4, it will allocate 40 bytes for the 10 character field.

Import Android volley to Android Studio

two things

one: compile is out of date rather it is better to use implementation,

and two: volley 1.0.0 is out of date and syncing project will no work

alternatively in build.gradle add implementation 'com.android.volley:volley:1.1.1' or implementation 'com.android.volley:volley:1.1.+' for 1.1.0 and newer versions.

CSS background opacity with rgba not working in IE 8

This solution really works, try it. Tested in IE8

.dash-overlay{ 
   -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#4C000000,endColorstr=#4C000000)"; 
}

What do \t and \b do?

The C standard (actually C99, I'm not up to date) says:

Alphabetic escape sequences representing nongraphic characters in the execution character set are intended to produce actions on display devices as follows:

\b (backspace) Moves the active position to the previous position on the current line. [...]

\t (horizontal tab) Moves the active position to the next horizontal tabulation position on the current line. [...]

Both just move the active position, neither are supposed to write any character on or over another character. To overwrite with a space you could try: puts("foo\b \tbar"); but note that on some display devices - say a daisy wheel printer - the o will show the transparent space.

Python - round up to the nearest ten

This will round down correctly as well:

>>> n = 46
>>> rem = n % 10
>>> if rem < 5:
...     n = int(n / 10) * 10
... else:
...     n = int((n + 10) / 10) * 10
...
>>> 50

When tracing out variables in the console, How to create a new line?

You should include it inside quotes '\n', See below,

console.log('roleName = '+roleName+ '\n' + 
             'role_ID = '+role_ID+  '\n' + 
             'modal_ID = '+modal_ID+ '\n' +  
             'related = '+related);

How do I localize the jQuery UI Datepicker?

  $.datepicker.setDefaults({
    closeText: "??",
    prevText: "&#x3C;??",
    nextText: "??&#x3E;",
    currentText: "??",
    monthNames: [ "??","??","??","??","??","??",
    "??","??","??","??","???","???" ],
    monthNamesShort: [ "??","??","??","??","??","??",
    "??","??","??","??","???","???" ],
    dayNames: [ "???","???","???","???","???","???","???" ],
    dayNamesShort: [ "??","??","??","??","??","??","??" ],
    dayNamesMin: [ "?","?","?","?","?","?","?" ],
    weekHeader: "?",
    dateFormat: "yy-mm-dd",
    firstDay: 1,
    isRTL: false,
    showMonthAfterYear: true,
    yearSuffix: "?"
  });

the i18n code could be copied from https://github.com/jquery/jquery-ui/tree/master/ui/i18n

How to install requests module in Python 3.4, instead of 2.7

On Windows with Python v3.6.5

py -m pip install requests

Executing periodic actions in Python

Surprised to not find a solution using a generator for timing. I just designed this one for my own purposes.

This solution: single threaded, no object instantiation each period, uses generator for times, rock solid on timing down to precision of the time module (unlike several of the solutions I've tried from stack exchange).

Note: for Python 2.x, replace next(g) below with g.next().

import time

def do_every(period,f,*args):
    def g_tick():
        t = time.time()
        while True:
            t += period
            yield max(t - time.time(),0)
    g = g_tick()
    while True:
        time.sleep(next(g))
        f(*args)

def hello(s):
    print('hello {} ({:.4f})'.format(s,time.time()))
    time.sleep(.3)

do_every(1,hello,'foo')

Results in, for example:

hello foo (1421705487.5811)
hello foo (1421705488.5811)
hello foo (1421705489.5809)
hello foo (1421705490.5830)
hello foo (1421705491.5803)
hello foo (1421705492.5808)
hello foo (1421705493.5811)
hello foo (1421705494.5811)
hello foo (1421705495.5810)
hello foo (1421705496.5811)
hello foo (1421705497.5810)
hello foo (1421705498.5810)
hello foo (1421705499.5809)
hello foo (1421705500.5811)
hello foo (1421705501.5811)
hello foo (1421705502.5811)
hello foo (1421705503.5810)

Note that this example includes a simulation of the cpu doing something else for .3 seconds each period. If you changed it to be random each time it wouldn't matter. The max in the yield line serves to protect sleep from negative numbers in case the function being called takes longer than the period specified. In that case it would execute immediately and make up the lost time in the timing of the next execution.

How to obtain the start time and end time of a day?

Java 8 or ThreeTenABP

ZonedDateTime

ZonedDateTime curDate = ZonedDateTime.now();

public ZonedDateTime startOfDay() {
    return curDate
    .toLocalDate()
    .atStartOfDay()
    .atZone(curDate.getZone())
    .withEarlierOffsetAtOverlap();
}

public ZonedDateTime endOfDay() {

    ZonedDateTime startOfTomorrow =
        curDate
        .toLocalDate()
        .plusDays(1)
        .atStartOfDay()
        .atZone(curDate.getZone())
        .withEarlierOffsetAtOverlap();

    return startOfTomorrow.minusSeconds(1);
}

// based on https://stackoverflow.com/a/29145886/1658268

LocalDateTime

LocalDateTime curDate = LocalDateTime.now();

public LocalDateTime startOfDay() {
    return curDate.atStartOfDay();
}

public LocalDateTime endOfDay() {
    return startOfTomorrow.atTime(LocalTime.MAX);  //23:59:59.999999999;
}

// based on https://stackoverflow.com/a/36408726/1658268

I hope that helps someone.

Change One Cell's Data in mysql

Try the following:

UPDATE TableName SET ValueName=@parameterName WHERE
IdName=@ParameterIdName

Regular expression - starting and ending with a character string

This should do it for you ^wp.*php$

Matches

wp-comments-post.php
wp.something.php
wp.php

Doesn't match

something-wp.php
wp.php.txt

Onchange open URL via select - jQuery

Try this code its working Firefox, Chrome, IE

<select onchange="this.options[this.selectedIndex].value && (window.location = this.options[this.selectedIndex].value);">
<option value="" selected>---Select---</option>
<option value="https://www.google.com">Google</option>
<option value="https://www.google.com">Google</option>
<option value="https://www.google.com">Google</option>
<option value="https://www.google.com">Google</option>

What is the difference between JOIN and UNION?

Union makes two queries look like one. Joins are for examining two or more tables in a single query statement

The type java.io.ObjectInputStream cannot be resolved. It is indirectly referenced from required .class files

same problem with me. This is not a solution but a workaround, which worked for me: Buildpath->Configure buildpath->Libraries-> Here remove the JRE system library pointing to JRE8 and add JRE system library for JRE7.

Understanding Fragment's setRetainInstance(boolean)

setRetainInstance() - Deprecated

As Fragments Version 1.3.0-alpha01

The setRetainInstance() method on Fragments has been deprecated. With the introduction of ViewModels, developers have a specific API for retaining state that can be associated with Activities, Fragments, and Navigation graphs. This allows developers to use a normal, not retained Fragment and keep the specific state they want retained separate, avoiding a common source of leaks while maintaining the useful properties of a single creation and destruction of the retained state (namely, the constructor of the ViewModel and the onCleared() callback it receives).

Set angular scope variable in markup

You can set values from html like this. I don't think there is a direct solution from angular yet.

 <div style="visibility: hidden;">{{activeTitle='home'}}</div>

When to use std::size_t?

By definition, size_t is the result of the sizeof operator. size_t was created to refer to sizes.

The number of times you do something (10, in your example) is not about sizes, so why use size_t? int, or unsigned int, should be ok.

Of course it is also relevant what you do with i inside the loop. If you pass it to a function which takes an unsigned int, for example, pick unsigned int.

In any case, I recommend to avoid implicit type conversions. Make all type conversions explicit.

ADB Install Fails With INSTALL_FAILED_TEST_ONLY

I tried external project, with multiple apk.

The command from Studio, looked like

adb install-multiple -r ....

Solution -

  • select console
  • aste command with -t

Difference between jQuery .hide() and .css("display", "none")

You can have a look at the source code (here it is v1.7.2).

Except for the animation that we can set, this also keep in memory the old display style (which is not in all cases block, it can also be inline, table-cell, ...).

PostgreSQL: Show tables in PostgreSQL

First of all you have to connect with your database like

my database is ubuntu

use this command to connect

 \c ubuntu

This message will show

"You are now connected to database "ubuntu" as user "postgres"."

Now

Run this command to show all tables in it

\d+

How to pass ArrayList<CustomeObject> from one activity to another?

you need implements Parcelable in your ContactBean class, I put one example for you:

public class ContactClass implements Parcelable {

private String id;
private String photo;
private String firstname;
private String lastname;

public ContactClass()
{

}

private ContactClass(Parcel in) {
    firstname = in.readString();
    lastname = in.readString();
    photo = in.readString();
    id = in.readString();

}

@Override
public int describeContents() {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {

    dest.writeString(firstname);
    dest.writeString(lastname);
    dest.writeString(photo);
    dest.writeString(id);

}

 public static final Parcelable.Creator<ContactClass> CREATOR = new Parcelable.Creator<ContactClass>() {
        public ContactClass createFromParcel(Parcel in) {
            return new ContactClass(in);
        }

        public ContactClass[] newArray(int size) {
            return new ContactClass[size];

        }
    };

   // all get , set method 
 }

and this get and set for your code:

Intent intent = new Intent(this,DisplayContact.class);
intent.putExtra("Contact_list", ContactLis);
startActivity(intent);

second class:

ArrayList<ContactClass> myList = getIntent().getParcelableExtra("Contact_list");

Angular-cli from css to scss

For Angular 6,

ng config schematics.@schematics/angular:component.styleext scss

note: @schematics/angular is the default schematic for the Angular CLI

Changing image on hover with CSS/HTML

check this fiddle

I think the image path may be wrong in your case

the syntax looks right

background-image:url('http://www.bluecowcreative.ca/wp-content/uploads/2013/08/hi.jpg');

TLS 1.2 in .NET Framework 4.0

I code in VB and was able to add the following line to my Global.asax.vb file inside of Application_Start

ServicePointManager.SecurityProtocol = CType(3072, SecurityProtocolType)    'TLS 1.2

How to properly seed random number generator

I don't understand why people are seeding with a time value. This has in my experience never been a good idea. For example, while the system clock is maybe represented in nanoseconds, the system's clock precision isn't nanoseconds.

This program should not be run on the Go playground but if you run it on your machine you get a rough estimate on what type of precision you can expect. I see increments of about 1000000 ns, so 1 ms increments. That's 20 bits of entropy that are not used. All the while the high bits are mostly constant!? Roughly ~24 bits of entropy over a day which is very brute forceable (which can create vulnerabilities).

The degree that this matters to you will vary but you can avoid pitfalls of clock based seed values by simply using the crypto/rand.Read as source for your seed. It will give you that non-deterministic quality that you are probably looking for in your random numbers (even if the actual implementation itself is limited to a set of distinct and deterministic random sequences).

import (
    crypto_rand "crypto/rand"
    "encoding/binary"
    math_rand "math/rand"
)

func init() {
    var b [8]byte
    _, err := crypto_rand.Read(b[:])
    if err != nil {
        panic("cannot seed math/rand package with cryptographically secure random number generator")
    }
    math_rand.Seed(int64(binary.LittleEndian.Uint64(b[:])))
}

As a side note but in relation to your question. You can create your own rand.Source using this method to avoid the cost of having locks protecting the source. The rand package utility functions are convenient but they also use locks under the hood to prevent the source from being used concurrently. If you don't need that you can avoid it by creating your own Source and use that in a non-concurrent way. Regardless, you should NOT be reseeding your random number generator between iterations, it was never designed to be used that way.

Why is pydot unable to find GraphViz's executables in Windows 8?

I had this issue and noticed that it was printing my PATH with two sets of double-quotes. I worked around the problem by adding the following to Line 1959 of:

C:\Anaconda\Lib\site-packages\pydot.py

self.progs[prog] = os.path.normpath(self.progs[prog][1:-1])

Obviously not the best fix but it got me through the day.

Laravel 5.4 Specific Table Migration

php artisan migrate --path=/database/migrations/fileName.php

You don't have to refresh for migration because refresh means Rollback all migrations and run them all again.

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)

"Strict Standards: Only variables should be passed by reference" error

array_shift the only parameter is an array passed by reference. The return value of explode(".", $value) does not have any reference. Hence the error.

You should store the return value to a variable first.

    $arr = explode(".", $value);
    $extension = strtolower(array_pop($arr));   
    $fileName = array_shift($arr);

From PHP.net

The following things can be passed by reference:

- Variables, i.e. foo($a)
- New statements, i.e. foo(new foobar())
- [References returned from functions][2]

No other expressions should be passed by reference, as the result is undefined. For example, the following examples of passing by reference are invalid:

Display SQL query results in php

You need to fetch the data from each row of the resultset obtained from the query. You can use mysql_fetch_array() for this.

// Process all rows
while($row = mysql_fetch_array($result)) {
    echo $row['column_name']; // Print a single column data
    echo print_r($row);       // Print the entire row data
}

Change your code to this :

require_once('db.php');  
$sql="SELECT * FROM  modul1open WHERE idM1O>=(SELECT FLOOR( MAX( idM1O ) * RAND( ) )  FROM  modul1open) 
ORDER BY idM1O LIMIT 1"

$result = mysql_query($sql);
while($row = mysql_fetch_array($result)) {
    echo $row['fieldname']; 
}

How do you handle a form change in jQuery?

First, I'd add a hidden input to your form to track the state of the form. Then, I'd use this jQuery snippet to set the value of the hidden input when something on the form changes:

    $("form")
    .find("input")
    .change(function(){
        if ($("#hdnFormChanged").val() == "no")
        {
            $("#hdnFormChanged").val("yes");
        }
    });

When your button is clicked, you can check the state of your hidden input:

$("#Button").click(function(){
    if($("#hdnFormChanged").val() == "yes")
    {
        // handler code here...
    }
});

Can I pass an array as arguments to a method with variable arguments in Java?

The underlying type of a variadic method function(Object... args) is function(Object[] args). Sun added varargs in this manner to preserve backwards compatibility.

So you should just be able to prepend extraVar to args and call String.format(format, args).

How to solve 'Redirect has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header'?

If you have control over your server, you can use PHP:

<?PHP
header('Access-Control-Allow-Origin: *');
?>

How to get the device's IMEI/ESN programmatically in android?

to get IMEI (international mobile equipment identifier)

public String getIMEI(Activity activity) {
    TelephonyManager telephonyManager = (TelephonyManager) activity
            .getSystemService(Context.TELEPHONY_SERVICE);
    return telephonyManager.getDeviceId();
}

to get device unique id

public String getDeviceUniqueID(Activity activity){
    String device_unique_id = Secure.getString(activity.getContentResolver(),
            Secure.ANDROID_ID);
    return device_unique_id;
}

Get month and year from date cells Excel

Please try something like:

=IF(LEN(C1)>10,VALUE(LEFT(C1,FIND(" ",C1,8))),IF(ISTEXT(C1),DATE(RIGHT(C1,4),MID(C1,4,2),LEFT(C1,2)),C1))  

You seem to have three main possible scenarios:

  1. Space-separated date with time as text (eg as A1 below)
  2. Hyphen-separated date as text (eg as A2 below)
  3. Formatted date index (as A4 and A5 below)

ColumnA below is formatted General and ColumnB as Date (my default setting). ColumnC also as date but with custom formatting to suit the appearances mentioned in your question.
A clue as to whether or not text format is the left or right alignment of the cells’ contents.

I am suggesting separate treatment for each of the above three main cases, so use =IF to differentiate them.

Case #1

This is longer than any of the others, so can be distinguished as having a length greater than say 10 characters, with =LEN.
In this case we want all but the last six characters but for added flexibility (for instance, in case the time element included seconds) I have chosen to count from the left rather than from the right. The problem then is that the month names may vary in length, so I have chosen to look for the space that immediately follows the year to indicate the limit for the relevant number of characters.

This with =FIND which looks for a space (" ") in C1, starting with the eighth character within C1 counting from the left, on the assumption that for this case days will be expressed as two characters and months as three or more.

Since =LEFT is a string function it returns a string, but this can be converted to a value with=VALUE.

So

=VALUE(LEFT(C1,FIND(" ",C1,8))) 

returns 40671 in this example – in Excel’s 1900 date system the date serial number for May 5, 2011.

Case #2

If the length of C1 is not greater than 10 characters, we still need to distinguish between a text entry or a value entry which I have chosen to do with =ISTEXT and, where the if condition is TRUE (as for C2) apply =DATE which takes three parameters, here provided by:

=RIGHT(C2,4)  

Takes the last four characters of C2, hence 2011 in this example.

=MID(C2,4,2) 

Starting at the fourth character, takes the next two characters of C2, hence 05 in this example (representing May).

=LEFT(C2,2))  

Takes the first two characters of C2, hence 08 in this example (representing the 8th day of the month). Date is not a text function so does not need to be wrapped in =VALUE.

Taken together

=DATE(RIGHT(C2,4),MID(C2,4,2),LEFT(C2,2)) 

also returns 40671 in this example, but from different input from Case #1.

Case #3

Is simple because already a date serial number, so just

=C2  

is sufficient.


Put the above together to cover all three cases in a single formula:

=IF(LEN(C1)>10,VALUE(LEFT(C1,FIND(" ",C1,8))),IF(ISTEXT(C1),DATE(RIGHT(C1,4),MID(C1,4,2),LEFT(C1,2)),C1))  

as applied in ColumnF (formatted to suit OP) or in General format (to show values are integers) in ColumnH:

SO23928568 example

What is difference between arm64 and armhf?

Update: Yes, I understand that this answer does not explain the difference between arm64 and armhf. There is a great answer that does explain that on this page. This answer was intended to help set the asker on the right path, as they clearly had a misunderstanding about the capabilities of the Raspberry Pi at the time of asking.

Where are you seeing that the architecture is armhf? On my Raspberry Pi 3, I get:

$ uname -a
armv7l

Anyway, armv7 indicates that the system architecture is 32-bit. The first ARM architecture offering 64-bit support is armv8. See this table for reference.

You are correct that the CPU in the Raspberry Pi 3 is 64-bit, but the Raspbian OS has not yet been updated for a 64-bit device. 32-bit software can run on a 64-bit system (but not vice versa). This is why you're not seeing the architecture reported as 64-bit.

You can follow the GitHub issue for 64-bit support here, if you're interested.

How to drop column with constraint?

First you should drop the problematic DEFAULT constraint, after that you can drop the column

alter table tbloffers drop constraint [ConstraintName]
go

alter table tbloffers drop column checkin

But the error may appear from other reasons - for example the user defined function or view with SCHEMABINDING option set for them.

UPD: Completely automated dropping of constraints script:

DECLARE @sql NVARCHAR(MAX)
WHILE 1=1
BEGIN
    SELECT TOP 1 @sql = N'alter table tbloffers drop constraint ['+dc.NAME+N']'
    from sys.default_constraints dc
    JOIN sys.columns c
        ON c.default_object_id = dc.object_id
    WHERE 
        dc.parent_object_id = OBJECT_ID('tbloffers')
    AND c.name = N'checkin'
    IF @@ROWCOUNT = 0 BREAK
    EXEC (@sql)
END

Centering floating divs within another div

I accomplished the above using relative positioning and floating to the right.

HTML code:

<div class="clearfix">                          
    <div class="outer-div">
        <div class="inner-div">
            <div class="floating-div">Float 1</div>
            <div class="floating-div">Float 2</div>
            <div class="floating-div">Float 3</div>
        </div>
    </div>
</div>

CSS:

.outer-div { position: relative; float: right; right: 50%; }
.inner-div { position: relative; float: right; right: -50%; }
.floating-div { float: left; border: 1px solid red; margin: 0 1.5em; }

.clearfix:before,
.clearfix:after { content: " "; display: table; }
.clearfix:after { clear: both; }
.clearfix { *zoom: 1; }

JSFiddle: http://jsfiddle.net/MJ9yp/

This will work in IE8 and up, but not earlier (surprise, surprise!)

I do not recall the source of this method unfortunately, so I cannot give credit to the original author. If anybody else knows, please post the link!

Image resizing client-side with JavaScript before upload to the server

If you were resizing before uploading I just found out this http://www.plupload.com/

It does all the magic for you in any imaginable method.

Unfortunately HTML5 resize only is supported with Mozilla browser, but you can redirect other browsers to Flash and Silverlight.

I just tried it and it worked with my android!

I was using http://swfupload.org/ in flash, it does the job very well, but the resize size is very small. (cannot remember the limit) and does not go back to html4 when flash is not available.

Best /Fastest way to read an Excel Sheet into a DataTable?

I found it pretty easy like this

    using System;
    using System.Data;
    using System.IO;
    using Excel;

    public DataTable ExcelToDataTableUsingExcelDataReader(string storePath)
    {
        FileStream stream = File.Open(storePath, FileMode.Open, FileAccess.Read);

        string fileExtension = Path.GetExtension(storePath);
        IExcelDataReader excelReader = null;
        if (fileExtension == ".xls")
        {
            excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
        }
        else if (fileExtension == ".xlsx")
        {
            excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
        }

        excelReader.IsFirstRowAsColumnNames = true;
        DataSet result = excelReader.AsDataSet();
        var test = result.Tables[0];
        return result.Tables[0];
    }

Note: you need to install SharpZipLib package for this

Install-Package SharpZipLib

neat and clean! ;)

Parse string to date with moment.js

No need for moment.js to parse the input since its format is the standard one :

var date = new Date('2014-02-27T10:00:00');
var formatted = moment(date).format('D MMMM YYYY');

http://es5.github.io/#x15.9.1.15

How to store custom objects in NSUserDefaults

Swift 4 introduced the Codable protocol which does all the magic for these kinds of tasks. Just conform your custom struct/class to it:

struct Player: Codable {
  let name: String
  let life: Double
}

And for storing in the Defaults you can use the PropertyListEncoder/Decoder:

let player = Player(name: "Jim", life: 3.14)
UserDefaults.standard.set(try! PropertyListEncoder().encode(player), forKey: kPlayerDefaultsKey)

let storedObject: Data = UserDefaults.standard.object(forKey: kPlayerDefaultsKey) as! Data
let storedPlayer: Player = try! PropertyListDecoder().decode(Player.self, from: storedObject)

It will work like that for arrays and other container classes of such objects too:

try! PropertyListDecoder().decode([Player].self, from: storedArray)

How to style HTML5 range input to have different color before and after slider?

Pure CSS solution:

  • Chrome: Hide the overflow from input[range], and fill all the space left to thumb with shadow color.
  • IE: no need to reinvent the wheel: ::-ms-fill-lower
  • Firefox no need to reinvent the wheel: ::-moz-range-progress

_x000D_
_x000D_
/*Chrome*/_x000D_
@media screen and (-webkit-min-device-pixel-ratio:0) {_x000D_
    input[type='range'] {_x000D_
      overflow: hidden;_x000D_
      width: 80px;_x000D_
      -webkit-appearance: none;_x000D_
      background-color: #9a905d;_x000D_
    }_x000D_
    _x000D_
    input[type='range']::-webkit-slider-runnable-track {_x000D_
      height: 10px;_x000D_
      -webkit-appearance: none;_x000D_
      color: #13bba4;_x000D_
      margin-top: -1px;_x000D_
    }_x000D_
    _x000D_
    input[type='range']::-webkit-slider-thumb {_x000D_
      width: 10px;_x000D_
      -webkit-appearance: none;_x000D_
      height: 10px;_x000D_
      cursor: ew-resize;_x000D_
      background: #434343;_x000D_
      box-shadow: -80px 0 0 80px #43e5f7;_x000D_
    }_x000D_
_x000D_
}_x000D_
/** FF*/_x000D_
input[type="range"]::-moz-range-progress {_x000D_
  background-color: #43e5f7; _x000D_
}_x000D_
input[type="range"]::-moz-range-track {  _x000D_
  background-color: #9a905d;_x000D_
}_x000D_
/* IE*/_x000D_
input[type="range"]::-ms-fill-lower {_x000D_
  background-color: #43e5f7; _x000D_
}_x000D_
input[type="range"]::-ms-fill-upper {  _x000D_
  background-color: #9a905d;_x000D_
}
_x000D_
<input type="range"/>
_x000D_
_x000D_
_x000D_

MySQL count occurrences greater than 2

SELECT count(word) as count 
FROM words 
GROUP BY word
HAVING count >= 2;

How to get current formatted date dd/mm/yyyy in Javascript and append it to an input

<input type="hidden" id="date"/>
<script>document.getElementById("date").value = new Date().toJSON().slice(0,10)</script>

How to equalize the scales of x-axis and y-axis in Python matplotlib?

You need to dig a bit deeper into the api to do this:

from matplotlib import pyplot as plt
plt.plot(range(5))
plt.xlim(-3, 3)
plt.ylim(-3, 3)
plt.gca().set_aspect('equal', adjustable='box')
plt.draw()

doc for set_aspect

Java Code for calculating Leap Year

this answer is great but it won't work for years before Christ (using a proleptic Gregorian calendar). If you want it to work for B.C. years, then use the following adaptation:

public static boolean isLeapYear(final int year) {
    final Calendar cal = Calendar.getInstance();
    if (year<0) {
        cal.set(Calendar.ERA, GregorianCalendar.BC);
        cal.set(Calendar.YEAR, -year);
    } else
        cal.set(Calendar.YEAR, year);
    return cal.getActualMaximum(Calendar.DAY_OF_YEAR) > 365;
}

You can verify that for yourself by considering that year -5 (i.e. 4 BC) should be pronounced as a leap year assuming a proleptic Gregorian calendar. Same with year -1 (the year before 1 AD). The linked to answer does not handle that case whereas the above adapted code does.

TypeError: can't use a string pattern on a bytes-like object in re.findall()

The problem is that your regex is a string, but html is bytes:

>>> type(html)
<class 'bytes'>

Since python doesn't know how those bytes are encoded, it throws an exception when you try to use a string regex on them.

You can either decode the bytes to a string:

html = html.decode('ISO-8859-1')  # encoding may vary!
title = re.findall(pattern, html)  # no more error

Or use a bytes regex:

regex = rb'<title>(,+?)</title>'
#        ^

In this particular context, you can get the encoding from the response headers:

with urllib.request.urlopen(url) as response:
    encoding = response.info().get_param('charset', 'utf8')
    html = response.read().decode(encoding)

See the urlopen documentation for more details.

MySQLDump one INSERT statement for each data row

In newer versions change was made to the flags: from the documentation:

--extended-insert, -e

Write INSERT statements using multiple-row syntax that includes several VALUES lists. This results in a smaller dump file and speeds up inserts when the file is reloaded.

--opt

This option, enabled by default, is shorthand for the combination of --add-drop-table --add-locks --create-options --disable-keys --extended-insert --lock-tables --quick --set-charset. It gives a fast dump operation and produces a dump file that can be reloaded into a MySQL server quickly.

Because the --opt option is enabled by default, you only specify its converse, the --skip-opt to turn off several default settings. See the discussion of mysqldump option groups for information about selectively enabling or disabling a subset of the options affected by --opt.

--skip-extended-insert

Turn off extended-insert

parent & child with position fixed, parent overflow:hidden bug

Fixed position elements are positioned relative to the browser window, so the parent element is basically irrelevant.

To get the effect you want, where the overflow on the parent clips the child, use position: absolute instead: http://jsfiddle.net/DBHUv/1/

How to change the default charset of a MySQL table?

The ALTER TABLE MySQL command should do the trick. The following command will change the default character set of your table and the character set of all its columns to UTF8.

ALTER TABLE etape_prospection CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

This command will convert all text-like columns in the table to the new character set. Character sets use different amounts of data per character, so MySQL will convert the type of some columns to ensure there's enough room to fit the same number of characters as the old column type.

I recommend you read the ALTER TABLE MySQL documentation before modifying any live data.

How to view table contents in Mysql Workbench GUI?

Inside the workbench right click the table in question and click "Select Rows - Limit 1000." It's the first option in the pop-up menu.

error LNK2001: unresolved external symbol (C++)

That means that the definition of your function is not present in your program. You forgot to add that one.cpp to your program.

What "to add" means in this case depends on your build environment and its terminology. In MSVC (since you are apparently use MSVC) you'd have to add one.cpp to the project.

In more practical terms, applicable to all typical build methodologies, when you link you program, the object file created form one.cpp is missing.

How to combine date from one field with time from another field - MS SQL Server

This worked for me

CAST(Tbl.date as DATETIME) + CAST(Tbl.TimeFrom AS TIME)

(on SQL 2008 R2)

OnItemClickListener using ArrayAdapter for ListView

Use OnItemClickListener

   ListView lv = getListView();
   lv.setOnItemClickListener(new OnItemClickListener()
   {
      @Override
      public void onItemClick(AdapterView<?> adapter, View v, int position,
            long arg3) 
      {
            String value = (String)adapter.getItemAtPosition(position); 
            // assuming string and if you want to get the value on click of list item
            // do what you intend to do on click of listview row
      }
   });

When you click on a row a listener is fired. So you setOnClickListener on the listview and use the annonymous inner class OnItemClickListener.

You also override onItemClick. The first param is a adapter. Second param is the view. third param is the position ( index of listview items).

Using the position you get the item .

Edit : From your comments i assume you need to set the adapter o listview

So assuming your activity extends ListActivtiy

     setListAdapter(adapter); 

Or if your activity class extends Activity

     ListView lv = (ListView) findViewById(R.id.listview1);
     //initialize adapter 
     lv.setAdapter(adapter); 

XAMPP, Apache - Error: Apache shutdown unexpectedly

  1. download new xampp apachefriends
  2. install it
  3. remove all VPN app
  4. open folder XAMPP run setup_xampp.bat
  5. run xampp-control.exe

Why is my locally-created script not allowed to run under the RemoteSigned execution policy?

this code line was working in Ubuntu with virtualbox and with Win 10 as a virtual os , inside of the powershell

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

If it is not working I recomand to read this resources below :

Set-ExecutionPolicy

Module: Microsoft.PowerShell.Security Sets the PowerShell execution policies for Windows computers.

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-executionpolicy?view=powershell-7.1#:~:text=To%20change%20the%20execution%20policy,Get%2DExecutionPolicy%20with%20no%20parameters.

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.security/get-executionpolicy?view=powershell-7.1

Get-ExecutionPolicy -List

https://devblogs.microsoft.com/scripting/hey-scripting-guy-how-can-i-sign-windows-powershell-scripts-with-an-enterprise-windows-pki-part-2-of-2/

Force table column widths to always be fixed regardless of contents

Specify the width of the table:

table
{
    table-layout: fixed;
    width: 100px;
}

See jsFiddle

Can Mysql Split a column?

Use

substring_index(`column`,',',1) ==> first value
substring_index(substring_index(`column`,',',-2),',',1)=> second value
substring_index(substring_index(`column`,',',-1),',',1)=> third value

in your where clause.

SELECT * FROM `table`
WHERE 
substring_index(`column`,',',1)<0 
AND
substring_index(`column`,',',1)>5

Why can't I use background image and color together?

Make half of the image transparent so the background colour is seen through it.

Else simply add another div taking up 50% up the container div and float it either left or right. Then apply either the image or the colour to it.

Manipulating an Access database from Java without ODBC

UCanAccess is a pure Java JDBC driver that allows us to read from and write to Access databases without using ODBC. It uses two other packages, Jackcess and HSQLDB, to perform these tasks. The following is a brief overview of how to get it set up.

 

Option 1: Using Maven

If your project uses Maven you can simply include UCanAccess via the following coordinates:

groupId: net.sf.ucanaccess
artifactId: ucanaccess

The following is an excerpt from pom.xml, you may need to update the <version> to get the most recent release:

  <dependencies>
    <dependency>
        <groupId>net.sf.ucanaccess</groupId>
        <artifactId>ucanaccess</artifactId>
        <version>4.0.4</version>
    </dependency>
  </dependencies>

 

Option 2: Manually adding the JARs to your project

As mentioned above, UCanAccess requires Jackcess and HSQLDB. Jackcess in turn has its own dependencies. So to use UCanAccess you will need to include the following components:

UCanAccess (ucanaccess-x.x.x.jar)
HSQLDB (hsqldb.jar, version 2.2.5 or newer)
Jackcess (jackcess-2.x.x.jar)
commons-lang (commons-lang-2.6.jar, or newer 2.x version)
commons-logging (commons-logging-1.1.1.jar, or newer 1.x version)

Fortunately, UCanAccess includes all of the required JAR files in its distribution file. When you unzip it you will see something like

ucanaccess-4.0.1.jar  
  /lib/
    commons-lang-2.6.jar  
    commons-logging-1.1.1.jar  
    hsqldb.jar  
    jackcess-2.1.6.jar

All you need to do is add all five (5) JARs to your project.

NOTE: Do not add loader/ucanload.jar to your build path if you are adding the other five (5) JAR files. The UcanloadDriver class is only used in special circumstances and requires a different setup. See the related answer here for details.

Eclipse: Right-click the project in Package Explorer and choose Build Path > Configure Build Path.... Click the "Add External JARs..." button to add each of the five (5) JARs. When you are finished your Java Build Path should look something like this

BuildPath.png

NetBeans: Expand the tree view for your project, right-click the "Libraries" folder and choose "Add JAR/Folder...", then browse to the JAR file.

nbAddJar.png

After adding all five (5) JAR files the "Libraries" folder should look something like this:

nbLibraries.png

IntelliJ IDEA: Choose File > Project Structure... from the main menu. In the "Libraries" pane click the "Add" (+) button and add the five (5) JAR files. Once that is done the project should look something like this:

IntelliJ.png

 

That's it!

Now "U Can Access" data in .accdb and .mdb files using code like this

// assumes...
//     import java.sql.*;
Connection conn=DriverManager.getConnection(
        "jdbc:ucanaccess://C:/__tmp/test/zzz.accdb");
Statement s = conn.createStatement();
ResultSet rs = s.executeQuery("SELECT [LastName] FROM [Clients]");
while (rs.next()) {
    System.out.println(rs.getString(1));
}

 

Disclosure

At the time of writing this Q&A I had no involvement in or affiliation with the UCanAccess project; I just used it. I have since become a contributor to the project.

The view or its master was not found or no view engine supports the searched locations

I came across this error due to the improper closing of the statement,

@using (Html.BeginForm("DeleteSelected", "Employee", FormMethod.Post))

{

} //This curly bracket needed to be closed at the end.

In Index.cshtml view file.I didn't close the statement at the end of the program. instead, I ended up closing improperly and ran into this error.

I was sure there isn't a need of checking Controller ActionMethod code because I have returned the Controller method properly to the View. So It has to be the view that's not responding and met with similar Error.

How to import JSON File into a TypeScript file?

I had read some of the responses and they didn't seem to work for me. I am using Typescript 2.9.2, Angular 6 and trying to import JSON in a Jasmine Unit Test. This is what did the trick for me.

Add:

"resolveJsonModule": true,

To tsconfig.json

Import like:

import * as nameOfJson from 'path/to/file.json';

Stop ng test, start again.

Reference: https://blogs.msdn.microsoft.com/typescript/2018/05/31/announcing-typescript-2-9/#json-imports

ctypes - Beginner

Here's a quick and dirty ctypes tutorial.

First, write your C library. Here's a simple Hello world example:

testlib.c

#include <stdio.h>

void myprint(void);

void myprint()
{
    printf("hello world\n");
}

Now compile it as a shared library (mac fix found here):

$ gcc -shared -Wl,-soname,testlib -o testlib.so -fPIC testlib.c

# or... for Mac OS X 
$ gcc -shared -Wl,-install_name,testlib.so -o testlib.so -fPIC testlib.c

Then, write a wrapper using ctypes:

testlibwrapper.py

import ctypes

testlib = ctypes.CDLL('/full/path/to/testlib.so')
testlib.myprint()

Now execute it:

$ python testlibwrapper.py

And you should see the output

Hello world
$

If you already have a library in mind, you can skip the non-python part of the tutorial. Make sure ctypes can find the library by putting it in /usr/lib or another standard directory. If you do this, you don't need to specify the full path when writing the wrapper. If you choose not to do this, you must provide the full path of the library when calling ctypes.CDLL().

This isn't the place for a more comprehensive tutorial, but if you ask for help with specific problems on this site, I'm sure the community would help you out.

PS: I'm assuming you're on Linux because you've used ctypes.CDLL('libc.so.6'). If you're on another OS, things might change a little bit (or quite a lot).

Call Javascript function from URL/address bar

you may also place the followinng

<a href='javascript:alert("hello world!");'>Click me</a>

to your html-code, and when you click on 'Click me' hyperlink, javascript will appear in url-bar and Alert dialog will show

history.replaceState() example?

The second argument Title does not mean Title of the page - It is more of a definition/information for the state of that page

But we can still change the title using onpopstate event, and passing the title name not from the second argument, but as an attribute from the first parameter passed as object

Reference: http://spoiledmilk.com/blog/html5-changing-the-browser-url-without-refreshing-page/

Get first n characters of a string

The Multibyte extension can come in handy if you need control over the string charset.

$charset = 'UTF-8';
$length = 10;
$string = 'Hai to yoo! I like yoo soo!';
if(mb_strlen($string, $charset) > $length) {
  $string = mb_substr($string, 0, $length - 3, $charset) . '...';
}

SAP Crystal Reports runtime for .Net 4.0 (64-bit)

SAP is notoriously bad at making these downloads available... or in an easily accessible location so hopefully this link still works by the time you read this answer.

< original link no longer active >

http://scn.sap.com/docs/DOC-7824 Updated Link 2/6/13:

https://wiki.scn.sap.com/wiki/display/BOBJ/Crystal+Reports%2C+Developer+for+Visual+Studio+Downloads - "Updated 10/31/2017"

http://www.crystalreports.com/crvs/confirm/ - "Updated 10/31/2017"

How to change text transparency in HTML/CSS?

Your best solution is to look at the "opacity" tag of an element.

For example:

.image
{
    opacity:0.4;
    filter:alpha(opacity=40); /* For IE8 and earlier */
}

So in your case it should look something like :

<html><span style="opacity: 0.5;"><font color=\"black\" face=\"arial\" size=\"4\">THIS IS MY TEXT</font></html>

However don't forget the tag isn't supported in HTML5.

You should use a CSS too :)

How can jQuery deferred be used?

Another use that I've been putting to good purpose is fetching data from multiple sources. In the example below, I'm fetching multiple, independent JSON schema objects used in an existing application for validation between a client and a REST server. In this case, I don't want the browser-side application to start loading data before it has all the schemas loaded. $.when.apply().then() is perfect for this. Thank to Raynos for pointers on using then(fn1, fn2) to monitor for error conditions.

fetch_sources = function (schema_urls) {
    var fetch_one = function (url) {
            return $.ajax({
                url: url,
                data: {},
                contentType: "application/json; charset=utf-8",
                dataType: "json",
            });
        }
    return $.map(schema_urls, fetch_one);
}

var promises = fetch_sources(data['schemas']);
$.when.apply(null, promises).then(

function () {
    var schemas = $.map(arguments, function (a) {
        return a[0]
    });
    start_application(schemas);
}, function () {
    console.log("FAIL", this, arguments);
});     

How to display the string html contents into webbrowser control?

The DisplayHtml(string html) recommended by m3z worked for me.

In case it helps somebody, I would also like to mention that initially there were some spaces in my HTML that invalidated the HTML and so the text appeared as a string. The spaces were introduced (around the angular brackets) when I pasted the HTML into Visual Studio. So if your text is still appearing as text after you try the solutions mentioned in this post, then it may be worth checking that the HTML syntax is correct.

Count characters in textarea

Keeping in mind what Etienne Martin says, you can use oninput, as it detects any change within texarea. Detect if you copy and paste text.

$('#textarea').on('input', function() {
        var max = 400;
        var len = $(this).val().length;
        var char = max - len;
        if (len >= max) {
            $('#charNum').text(' You have reached the character limit.');
            $('#charNum').addClass("text-danger"); // optional, adding a class using bootstrap
        } else if (char <= 10) {
            $('#charNum').text(char + ' You are reaching the character limit.');
            $('#charNum').addClass("text-warning"); // optional, adding a class using bootstrap
        } else {
            var char = max - len;
            $('#charNum').text(char + ' characters remaining.');
            $('#charNum').addClass("text-success"); // optional, adding a class using bootstrap
        }
        });

I can't install python-ldap

For alpine docker

apk add openldap-dev

if the python version is 3 and above try

pip install python3-ldap

How to fill background image of an UIView

The colorWithPattern: method is really for generating patterns from images. Thus, the customization you require is most likely not possible, nor is it meant to be.

Indeed you need to use a UIImageView to center and scale an image. The fact that you have a UIScrollView does not prevent this:

Make self.view a generic view, then add both the UIImageView and the UIScrollView as subviews. Make sure all is wired up correctly in Interface Builder, and make the background color of the scroll view transparent.

This is IMHO the simplest and most flexible design for future changes.

How to add one day to a date?

tl;dr

LocalDate.of( 2017 , Month.JANUARY , 23 ) 
         .plusDays( 1 )

java.time

Best to avoid the java.util.Date class altogether. But if you must do so, you can convert between the troublesome old legacy date-time classes and the modern java.time classes. Look to new methods added to the old classes.

Instant

The Instant class, is close to being equivalent to Date, both being a moment on the timeline. Instant resolves to nanoseconds, while Date is milliseconds.

Instant instant = myUtilDate.toInstant() ;

You could add a day to this, but keep in mind this in UTC. So you will not be accounting for anomalies such as Daylight Saving Time. Specify the unit of time with the ChronoUnit class.

Instant nextDay = instant.plus( 1 , ChronoUnit.DAYS ) ;

ZonedDateTime

If you want to be savvy with time zones, specify a ZoneId to get a ZonedDateTime. Specify a proper time zone name in the format of continent/region, such as America/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 3-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).

ZoneId z = ZoneId.of( "America/Montreal" ) ;
ZonedDateTime zdt = instant.atZone( z ) ;
ZonedDateTime zdtNextDay = zdt.plusDays( 1 ) ;

You can also represent your span-of-time to be added, the one day, as a Period.

Period p = Period.ofDays( 1 ) ;
ZonedDateTime zdt = ZonedDateTime.now( z ).plus( p ) ;

You may want the first moment of that next day. Do not assume the day starts at 00:00:00. Anomalies such as Daylight Saving Time (DST) mean the day may start at another time, such as 01:00:00. Let java.time determine the first moment of the day on that date in that zone.

LocalDate today = LocalDate.now( z ) ;
LocalDate tomorrow = today.plus( p ) ;
ZonedDateTime zdt = tomorrow.atStartOfDay( z ) ;

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.


Update: The Joda-Time library is now in maintenance mode. The team advises migration to the java.time classes. I am leaving this section intact for history.

Joda-Time

The Joda-Time 2.3 library makes this kind of date-time work much easier. The java.util.Date class bundled with Java is notoriously troublesome, and should be avoided.

Here is some example code.

Your java.util.Date is converted to a Joda-Time DateTime object. Unlike a j.u.Date, a DateTime truly knows its assigned time zone. Time zone is crucial as adding a day to get the same wall-clock time tomorrow might mean making adjustments such as for a 23-hour or 25-hour day in the case of Daylight Saving Time (DST) here in the United States. If you specify the time zone, Joda-Time can make that kind of adjustment. After adding a day, we convert the DateTime object back into a java.util.Date object.

java.util.Date yourDate = new java.util.Date();

// Generally better to specify your time zone rather than rely on default.
org.joda.time.DateTimeZone timeZone = org.joda.time.DateTimeZone.forID( "America/Los_Angeles" );
DateTime now = new DateTime( yourDate, timeZone );
DateTime tomorrow = now.plusDays( 1 );
java.util.Date tomorrowAsJUDate = tomorrow.toDate();

Dump to console…

System.out.println( "yourDate: " + yourDate );
System.out.println( "now: " + now );
System.out.println( "tomorrow: " + tomorrow );
System.out.println( "tomorrowAsJUDate: " + tomorrowAsJUDate );

When run…

yourDate: Thu Apr 10 22:57:21 PDT 2014
now: 2014-04-10T22:57:21.535-07:00
tomorrow: 2014-04-11T22:57:21.535-07:00
tomorrowAsJUDate: Fri Apr 11 22:57:21 PDT 2014

JNI converting jstring to char *

Thanks Jason Rogers's answer first.

In Android && cpp should be this:

const char *nativeString = env->GetStringUTFChars(javaString, nullptr);

// use your string

env->ReleaseStringUTFChars(javaString, nativeString);

Can fix this errors:

1.error: base operand of '->' has non-pointer type 'JNIEnv {aka _JNIEnv}'

2.error: no matching function for call to '_JNIEnv::GetStringUTFChars(JNIEnv*&, _jstring*&, bool)'

3.error: no matching function for call to '_JNIEnv::ReleaseStringUTFChars(JNIEnv*&, _jstring*&, char const*&)'

4.add "env->DeleteLocalRef(nativeString);" at end.

How do you uninstall all dependencies listed in package.json (NPM)?

First, remove all packages from dependencies and devDependencies in package.json

Second, run npm install

That simple.

CSS Float: Floating an image to the left of the text

Check out this sample: http://jsfiddle.net/Epgvc/1/

I just floated the title to the left and added a clear:both div to the bottom..

Java: Difference between the setPreferredSize() and setSize() methods in components

setSize() or setBounds() can be used when no layout manager is being used.

However, if you are using a layout manager you can provide hints to the layout manager using the setXXXSize() methods like setPreferredSize() and setMinimumSize() etc.

And be sure that the component's container uses a layout manager that respects the requested size. The FlowLayout, GridBagLayout, and SpringLayout managers use the component's preferred size (the latter two depending on the constraints you set), but BorderLayout and GridLayout usually don't.If you specify new size hints for a component that's already visible, you need to invoke the revalidate method on it to make sure that its containment hierarchy is laid out again. Then invoke the repaint method.

Docker - Container is not running

Container 79b3fa70b51d seems to only do an echo.

That means it starts, echo and then exits immediately.

The next docker exec command wouldn't find it running in order to attach itself to that container and execute any command: it is too late. The container has already exited.

The docker exec command runs a new command in a running container.

The command started using docker exec will only run while the container's primary process (PID 1) is running

Reading text files using read.table

From ?read.table: The number of data columns is determined by looking at the first five lines of input (or the whole file if it has less than five lines), or from the length of col.names if it is specified and is longer. This could conceivably be wrong if fill or blank.lines.skip are true, so specify col.names if necessary.

So, perhaps your data file isn't clean. Being more specific will help the data import:

d = read.table("foobar.txt", 
               sep="\t", 
               col.names=c("id", "name"), 
               fill=FALSE, 
               strip.white=TRUE)

will specify exact columns and fill=FALSE will force a two column data frame.

How to convert integers to characters in C?

char c1 = (char)97;  //c1 = 'a'

int i = 98;
char c2 = (char)i;  //c2 = 'b'

C++ inheritance - inaccessible base?

By default, inheritance is private. You have to explicitly use public:

class Bar : public Foo

In Javascript, how do I check if an array has duplicate values?

If you have an ES2015 environment (as of this writing: io.js, IE11, Chrome, Firefox, WebKit nightly), then the following will work, and will be fast (viz. O(n)):

function hasDuplicates(array) {
    return (new Set(array)).size !== array.length;
}

If you only need string values in the array, the following will work:

function hasDuplicates(array) {
    var valuesSoFar = Object.create(null);
    for (var i = 0; i < array.length; ++i) {
        var value = array[i];
        if (value in valuesSoFar) {
            return true;
        }
        valuesSoFar[value] = true;
    }
    return false;
}

We use a "hash table" valuesSoFar whose keys are the values we've seen in the array so far. We do a lookup using in to see if that value has been spotted already; if so, we bail out of the loop and return true.


If you need a function that works for more than just string values, the following will work, but isn't as performant; it's O(n2) instead of O(n).

function hasDuplicates(array) {
    var valuesSoFar = [];
    for (var i = 0; i < array.length; ++i) {
        var value = array[i];
        if (valuesSoFar.indexOf(value) !== -1) {
            return true;
        }
        valuesSoFar.push(value);
    }
    return false;
}

The difference is simply that we use an array instead of a hash table for valuesSoFar, since JavaScript "hash tables" (i.e. objects) only have string keys. This means we lose the O(1) lookup time of in, instead getting an O(n) lookup time of indexOf.

How to Create a script via batch file that will uninstall a program if it was installed on windows 7 64-bit or 32-bit

Assuming you're dealing with Windows 7 x64 and something that was previously installed with some sort of an installer, you can open regedit and search the keys under

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall

(which references 32-bit programs) for part of the name of the program, or

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

(if it actually was a 64-bit program).

If you find something that matches your program in one of those, the contents of UninstallString in that key usually give you the exact command you are looking for (that you can run in a script).

If you don't find anything relevant in those registry locations, then it may have been "installed" by unzipping a file. Because you mentioned removing it by the Control Panel, I gather this likely isn't then case; if it's in the list of programs there, it should be in one of the registry keys I mentioned.

Then in a .bat script you can do

if exist "c:\program files\whatever\program.exe" (place UninstallString contents here)
if exist "c:\program files (x86)\whatever\program.exe" (place UninstallString contents here)

HTML5 video - show/hide controls programmatically

Here's how to do it:

var myVideo = document.getElementById("my-video")    
myVideo.controls = false;

Working example: https://jsfiddle.net/otnfccgu/2/

See all available properties, methods and events here: https://www.w3schools.com/TAGs/ref_av_dom.asp

Letsencrypt add domain to existing certificate

You need to specify all of the names, including those already registered.

I used the following command originally to register some certificates:

/opt/certbot/certbot-auto certonly --webroot --agree-tos -w /srv/www/letsencrypt/ \
--email [email protected] \
--expand -d example.com,www.example.com

... and just now I successfully used the following command to expand my registration to include a new subdomain as a SAN:

/opt/certbot/certbot-auto certonly --webroot --agree-tos -w /srv/www/letsencrypt/ \
--expand -d example.com,www.example.com,click.example.com

From the documentation:

--expand "If an existing cert covers some subset of the requested names, always expand and replace it with the additional names."

Don't forget to restart the server to load the new certificates if you are running nginx.

How to solve Object reference not set to an instance of an object.?

I think you just need;

List<string> list = new List<string>();
list.Add("hai");

There is a difference between

List<string> list; 

and

List<string> list = new List<string>();

When you didn't use new keyword in this case, your list didn't initialized. And when you try to add it hai, obviously you get an error.

How to change the background color on a input checkbox with css?

I always use pseudo elements :before and :after for changing the appearance of checkboxes and radio buttons. it's works like a charm.

Refer this link for more info

CODEPEN

Steps

  1. Hide the default checkbox using css rules like visibility:hidden or opacity:0 or position:absolute;left:-9999px etc.
  2. Create a fake checkbox using :before element and pass either an empty or a non-breaking space '\00a0';
  3. When the checkbox is in :checked state, pass the unicode content: "\2713", which is a checkmark;
  4. Add :focus style to make the checkbox accessible.
  5. Done

Here is how I did it.

_x000D_
_x000D_
.box {_x000D_
  background: #666666;_x000D_
  color: #ffffff;_x000D_
  width: 250px;_x000D_
  padding: 10px;_x000D_
  margin: 1em auto;_x000D_
}_x000D_
p {_x000D_
  margin: 1.5em 0;_x000D_
  padding: 0;_x000D_
}_x000D_
input[type="checkbox"] {_x000D_
  visibility: hidden;_x000D_
}_x000D_
label {_x000D_
  cursor: pointer;_x000D_
}_x000D_
input[type="checkbox"] + label:before {_x000D_
  border: 1px solid #333;_x000D_
  content: "\00a0";_x000D_
  display: inline-block;_x000D_
  font: 16px/1em sans-serif;_x000D_
  height: 16px;_x000D_
  margin: 0 .25em 0 0;_x000D_
  padding: 0;_x000D_
  vertical-align: top;_x000D_
  width: 16px;_x000D_
}_x000D_
input[type="checkbox"]:checked + label:before {_x000D_
  background: #fff;_x000D_
  color: #333;_x000D_
  content: "\2713";_x000D_
  text-align: center;_x000D_
}_x000D_
input[type="checkbox"]:checked + label:after {_x000D_
  font-weight: bold;_x000D_
}_x000D_
_x000D_
input[type="checkbox"]:focus + label::before {_x000D_
    outline: rgb(59, 153, 252) auto 5px;_x000D_
}
_x000D_
<div class="content">_x000D_
  <div class="box">_x000D_
    <p>_x000D_
      <input type="checkbox" id="c1" name="cb">_x000D_
      <label for="c1">Option 01</label>_x000D_
    </p>_x000D_
    <p>_x000D_
      <input type="checkbox" id="c2" name="cb">_x000D_
      <label for="c2">Option 02</label>_x000D_
    </p>_x000D_
    <p>_x000D_
      <input type="checkbox" id="c3" name="cb">_x000D_
      <label for="c3">Option 03</label>_x000D_
    </p>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Much more stylish using :before and :after

_x000D_
_x000D_
body{_x000D_
  font-family: sans-serif;  _x000D_
}_x000D_
_x000D_
.container {_x000D_
    margin-top: 50px;_x000D_
    margin-left: 20px;_x000D_
    margin-right: 20px;_x000D_
}_x000D_
.checkbox {_x000D_
    width: 100%;_x000D_
    margin: 15px auto;_x000D_
    position: relative;_x000D_
    display: block;_x000D_
}_x000D_
_x000D_
.checkbox input[type="checkbox"] {_x000D_
    width: auto;_x000D_
    opacity: 0.00000001;_x000D_
    position: absolute;_x000D_
    left: 0;_x000D_
    margin-left: -20px;_x000D_
}_x000D_
.checkbox label {_x000D_
    position: relative;_x000D_
}_x000D_
.checkbox label:before {_x000D_
    content: '';_x000D_
    position: absolute;_x000D_
    left: 0;_x000D_
    top: 0;_x000D_
    margin: 4px;_x000D_
    width: 22px;_x000D_
    height: 22px;_x000D_
    transition: transform 0.28s ease;_x000D_
    border-radius: 3px;_x000D_
    border: 2px solid #7bbe72;_x000D_
}_x000D_
.checkbox label:after {_x000D_
  content: '';_x000D_
    display: block;_x000D_
    width: 10px;_x000D_
    height: 5px;_x000D_
    border-bottom: 2px solid #7bbe72;_x000D_
    border-left: 2px solid #7bbe72;_x000D_
    -webkit-transform: rotate(-45deg) scale(0);_x000D_
    transform: rotate(-45deg) scale(0);_x000D_
    transition: transform ease 0.25s;_x000D_
    will-change: transform;_x000D_
    position: absolute;_x000D_
    top: 12px;_x000D_
    left: 10px;_x000D_
}_x000D_
.checkbox input[type="checkbox"]:checked ~ label::before {_x000D_
    color: #7bbe72;_x000D_
}_x000D_
_x000D_
.checkbox input[type="checkbox"]:checked ~ label::after {_x000D_
    -webkit-transform: rotate(-45deg) scale(1);_x000D_
    transform: rotate(-45deg) scale(1);_x000D_
}_x000D_
_x000D_
.checkbox label {_x000D_
    min-height: 34px;_x000D_
    display: block;_x000D_
    padding-left: 40px;_x000D_
    margin-bottom: 0;_x000D_
    font-weight: normal;_x000D_
    cursor: pointer;_x000D_
    vertical-align: sub;_x000D_
}_x000D_
.checkbox label span {_x000D_
    position: absolute;_x000D_
    top: 50%;_x000D_
    -webkit-transform: translateY(-50%);_x000D_
    transform: translateY(-50%);_x000D_
}_x000D_
.checkbox input[type="checkbox"]:focus + label::before {_x000D_
    outline: 0;_x000D_
}
_x000D_
<div class="container"> _x000D_
  <div class="checkbox">_x000D_
     <input type="checkbox" id="checkbox" name="" value="">_x000D_
     <label for="checkbox"><span>Checkbox</span></label>_x000D_
  </div>_x000D_
_x000D_
  <div class="checkbox">_x000D_
     <input type="checkbox" id="checkbox2" name="" value="">_x000D_
     <label for="checkbox2"><span>Checkbox</span></label>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Get root view from current activity

anyview.getRootView(); will be the easiest way.

Move_uploaded_file() function is not working

If you are on a windows machine, there won't be any problems with uploading or writing to the specified folder path, except the syntactical errors.

But in case of Linux users, there is a workaround to this problem, even if there are no syntactical errors visible.

First of all, I am assuming that you are using this in a Linux environment and you need to upload something to your project folder in the public directory.

Even if you are having the write and read access to the project folder, PHP is not handled by the end user. It is and can be handled by a www-data user, or group.

So in order to make this www-data get access first type in;

sudo chgrp "www-data" your_project_folder

once its done, if there is no write access to the following as well;

sudo chown g+w your_project_folder

That will do the trick in Linux.

Please, not that this is done in a Linux environment, with phpmyadmin, and mysql running.

Putting a simple if-then-else statement on one line

count = 0 if count == N else N+1

- the ternary operator. Although I'd say your solution is more readable than this.

How to draw a line in android

To improve on the answers provided by @Janusz

I added this to my styles:

<style name="Divider">
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">1dp</item>
    <item name="android:background">?android:attr/listDivider</item>
</style>

Then in my layouts is less code and simpler to read.

<View style="@style/Divider"/>

if you want to do horizontal line spacing then do the above.


And for vertical line between two Views you have to replace android:layout_width parameters(attributes) with android:layout_height

Selenium WebDriver findElement(By.xpath()) not working for me

You should add the tag name in the xpath, like:

element = findElement(By.xpath("//input[@test-id='test-username']");

In MVC, how do I return a string result?

You can also just return string if you know that's the only thing the method will ever return. For example:

public string MyActionName() {
  return "Hi there!";
}

How do I create a GUI for a windows application using C++?

I strongly prefer simply using Microsoft Visual Studio and writing a native Win32 app.

For a GUI as simple as the one that you describe, you could simply create a Dialog Box and use it as your main application window. The default application created by the Win32 Project wizard in Visual Studio actually pops a window, so you can replace that window with your Dialog Box and replace the WndProc with a similar (but simpler) DialogProc.

The question, then, is one of tools and cost. The Express Edition of Visual C++ does everything you want except actually create the Dialog Template resource. For this, you could either code it in the RC file by hand or in memory by hand. Related SO question: Windows API Dialogs without using resource files.

Or you could try one of the free resource editors that others have recommended.

Finally, the Visual Studio 2008 Standard Edition is a costlier option but gives you an integrated resource editor.

Print in Landscape format

you cannot set this in javascript, you have to do this with html/css:

<style type="text/css" media="print">
  @page { size: landscape; }
</style>

EDIT: See this Question and the accepted answer for more information on browser support: Is @Page { size:landscape} obsolete?

How do I associate file types with an iPhone application?

To deal with any type of files for my own APP, I use this configuration for CFBundleDocumentTypes:

    <key>CFBundleDocumentTypes</key>
    <array>
        <dict>
            <key>CFBundleTypeName</key>
            <string>IPA</string>
            <key>LSItemContentTypes</key>
            <array>
                <string>public.item</string>
                <string>public.content</string>
                <string>public.data</string>
                <string>public.database</string>
                <string>public.composite-content</string>
                <string>public.contact</string>
                <string>public.archive</string>
                <string>public.url-name</string>
                <string>public.text</string>
                <string>public.plain-text</string>
                <string>public.source-code</string>
                <string>public.executable</string>
                <string>public.script</string>
                <string>public.shell-script</string>
                <string>public.xml</string>
                <string>public.symlink</string>
                <string>org.gnu.gnu-zip-archve</string>
                <string>org.gnu.gnu-tar-archive</string>
                <string>public.image</string>
                <string>public.movie</string>
                <string>public.audiovisual-?content</string>
                <string>public.audio</string>
                <string>public.directory</string>
                <string>public.folder</string>
                <string>com.apple.bundle</string>
                <string>com.apple.package</string>
                <string>com.apple.plugin</string>
                <string>com.apple.application-?bundle</string>
                <string>com.pkware.zip-archive</string>
                <string>public.filename-extension</string>
                <string>public.mime-type</string>
                <string>com.apple.ostype</string>
                <string>com.apple.nspboard-typ</string>
                <string>com.adobe.pdf</string>
                <string>com.adobe.postscript</string>
                <string>com.adobe.encapsulated-?postscript</string>
                <string>com.adobe.photoshop-?image</string>
                <string>com.adobe.illustrator.ai-?image</string>
                <string>com.compuserve.gif</string>
                <string>com.microsoft.word.doc</string>
                <string>com.microsoft.excel.xls</string>
                <string>com.microsoft.powerpoint.?ppt</string>
                <string>com.microsoft.waveform-?audio</string>
                <string>com.microsoft.advanced-?systems-format</string>
                <string>com.microsoft.advanced-?stream-redirector</string>
                <string>com.microsoft.windows-?media-wmv</string>
                <string>com.microsoft.windows-?media-wmp</string>
                <string>com.microsoft.windows-?media-wma</string>
                <string>com.apple.keynote.key</string>
                <string>com.apple.keynote.kth</string>
                <string>com.truevision.tga-image</string>
            </array>
            <key>CFBundleTypeIconFiles</key>
            <array>
                <string>Icon-76@2x</string>
            </array>
        </dict>
    </array>

How to use Python to login to a webpage and retrieve cookies for later usage?

Here's a version using the excellent requests library:

from requests import session

payload = {
    'action': 'login',
    'username': USERNAME,
    'password': PASSWORD
}

with session() as c:
    c.post('http://example.com/login.php', data=payload)
    response = c.get('http://example.com/protected_page.php')
    print(response.headers)
    print(response.text)

Java Synchronized list

You can have 2 diffent problems with lists :
1) If you do a modification within an iteration even though in a mono thread environment, you will have ConcurrentModificationException like in this following example :

List<String> list = new ArrayList<String>();
for (int i=0;i<5;i++)
   list.add("Hello "+i);

for(String msg:list)
   list.remove(msg);

So, to avoid this problem, you can do :

for(int i=list.size()-1;i>=0;i--)
   list.remove(i);

2)The second problem could be multi threading environment. As mentioned above, you can use synchronized(list) to avoid exceptions.

How to fetch data from local JSON file on react native?

Since React Native 0.4.3 you can read your local JSON file like this:

const customData = require('./customData.json');

and then access customData like a normal JS object.

how to define variable in jquery

Here's are some examples:

var name = 'india';
alert(name);  


var name = $("#txtname").val();
alert(name);

Taken from http://way2finder.blogspot.in/2013/09/how-to-create-variable-in-jquery.html

Can't connect to localhost on SQL Server Express 2012 / 2016

First check SQL Server Service is Running or stopped, if it is stopped just start it, to do so..just follow the below steps.

1.Start -> Run ->Services.msc

enter image description here

  1. Go to Standard tab in services panel then search for SQl Server(SQL2014)

"SQL2014" is given By me, it may be Another Name in your case

enter image description here

that's it once you start the SQL Service, you are able to connect local database.

hope it will help someone.

When is the init() function run?

mutil init function in one package execute order:

  1. const and variable defined file init() function execute

  2. init function execute order by the filename asc

Delete files older than 3 months old in a directory using .NET

An SSIS type of example .. (if this helps anyone)

          public void Main()
          {
                 // TODO: Add your code here
        // Author: Allan F 10th May 2019

        //first part of process .. put any files of last Qtr (or older) in Archive area 
        //e.g. if today is 10May2019 then last quarter is 1Jan2019 to 31March2019 .. any files earlier than 31March2019 will be archived

        //string SourceFileFolder = "\\\\adlsaasf11\\users$\\aford05\\Downloads\\stage\\";
        string SourceFilesFolder = (string)Dts.Variables["SourceFilesFolder"].Value;
        string ArchiveFolder = (string)Dts.Variables["ArchiveFolder"].Value;
        string FilePattern = (string)Dts.Variables["FilePattern"].Value;
        string[] files = Directory.GetFiles(SourceFilesFolder, FilePattern);

        //DateTime date = new DateTime(2019, 2, 15);//commented out line .. just for testing the dates .. 

        DateTime date = DateTime.Now;
        int quarterNumber = (date.Month - 1) / 3 + 1;
        DateTime firstDayOfQuarter = new DateTime(date.Year, (quarterNumber - 1) * 3 + 1, 1);
        DateTime lastDayOfQuarter = firstDayOfQuarter.AddMonths(3).AddDays(-1);

        DateTime LastDayOfPriorQuarter = firstDayOfQuarter.AddDays(-1);
        int PrevQuarterNumber = (LastDayOfPriorQuarter.Month - 1) / 3 + 1;
        DateTime firstDayOfLastQuarter = new DateTime(LastDayOfPriorQuarter.Year, (PrevQuarterNumber - 1) * 3 + 1, 1);
        DateTime lastDayOfLastQuarter = firstDayOfLastQuarter.AddMonths(3).AddDays(-1);

        //MessageBox.Show("debug pt2: firstDayOfQuarter" + firstDayOfQuarter.ToString("dd/MM/yyyy"));
        //MessageBox.Show("debug pt2: firstDayOfLastQuarter" + firstDayOfLastQuarter.ToString("dd/MM/yyyy"));


        foreach (string file in files)
        {
            FileInfo fi = new FileInfo(file);

            //MessageBox.Show("debug pt2:" + fi.Name + " " + fi.CreationTime.ToString("dd/MM/yyyy HH:mm") + " " + fi.LastAccessTime.ToString("dd/MM/yyyy HH:mm") + " " + fi.LastWriteTime.ToString("dd/MM/yyyy HH:mm"));
            if (fi.LastWriteTime < firstDayOfQuarter)
            {

                try
                {

                    FileInfo fi2 = new FileInfo(ArchiveFolder);

                    //Ensure that the target does not exist.
                    //fi2.Delete();

                    //Copy the file.
                    fi.CopyTo(ArchiveFolder + fi.Name);
                    //Console.WriteLine("{0} was copied to {1}.", path, ArchiveFolder);

                    //Delete the old location file.
                    fi.Delete();
                    //Console.WriteLine("{0} was successfully deleted.", ArchiveFolder);

                }
                catch (Exception e)
                {
                    //do nothing
                    //Console.WriteLine("The process failed: {0}", e.ToString());
                }
            }
        }

        //second part of process .. delete any files in Archive area dated earlier than last qtr ..
        //e.g. if today is 10May2019 then last quarter is 1Jan2019 to 31March2019 .. any files earlier than 1Jan2019 will be deleted

        string[] archivefiles = Directory.GetFiles(ArchiveFolder, FilePattern);
        foreach (string archivefile in archivefiles)
        {
            FileInfo fi = new FileInfo(archivefile);
            if (fi.LastWriteTime < firstDayOfLastQuarter )
            {
                try
                {
                    fi.Delete();
                }
                catch (Exception e)
                {
                    //do nothing
                }
            }
        }


                 Dts.TaskResult = (int)ScriptResults.Success;
          }

python to arduino serial read & write

You shouldn't be closing the serial port in Python between writing and reading. There is a chance that the port is still closed when the Arduino responds, in which case the data will be lost.

while running:  
    # Serial write section
    setTempCar1 = 63
    setTempCar2 = 37
    setTemp1 = str(setTempCar1)
    setTemp2 = str(setTempCar2)
    print ("Python value sent: ")
    print (setTemp1)
    ard.write(setTemp1)
    time.sleep(6) # with the port open, the response will be buffered 
                  # so wait a bit longer for response here

    # Serial read section
    msg = ard.read(ard.inWaiting()) # read everything in the input buffer
    print ("Message from arduino: ")
    print (msg)

The Python Serial.read function only returns a single byte by default, so you need to either call it in a loop or wait for the data to be transmitted and then read the whole buffer.

On the Arduino side, you should consider what happens in your loop function when no data is available.

void loop()
{
  // serial read section
  while (Serial.available()) // this will be skipped if no data present, leading to
                             // the code sitting in the delay function below
  {
    delay(30);  //delay to allow buffer to fill 
    if (Serial.available() >0)
    {
      char c = Serial.read();  //gets one byte from serial buffer
      readString += c; //makes the string readString
    }
  }

Instead, wait at the start of the loop function until data arrives:

void loop()
{
  while (!Serial.available()) {} // wait for data to arrive
  // serial read section
  while (Serial.available())
  {
    // continue as before

EDIT 2

Here's what I get when interfacing with your Arduino app from Python:

>>> import serial
>>> s = serial.Serial('/dev/tty.usbmodem1411', 9600, timeout=5)
>>> s.write('2')
1
>>> s.readline()
'Arduino received: 2\r\n'

So that seems to be working fine.

In testing your Python script, it seems the problem is that the Arduino resets when you open the serial port (at least my Uno does), so you need to wait a few seconds for it to start up. You are also only reading a single line for the response, so I've fixed that in the code below also:

#!/usr/bin/python
import serial
import syslog
import time

#The following line is for serial over GPIO
port = '/dev/tty.usbmodem1411' # note I'm using Mac OS-X


ard = serial.Serial(port,9600,timeout=5)
time.sleep(2) # wait for Arduino

i = 0

while (i < 4):
    # Serial write section

    setTempCar1 = 63
    setTempCar2 = 37
    ard.flush()
    setTemp1 = str(setTempCar1)
    setTemp2 = str(setTempCar2)
    print ("Python value sent: ")
    print (setTemp1)
    ard.write(setTemp1)
    time.sleep(1) # I shortened this to match the new value in your Arduino code

    # Serial read section
    msg = ard.read(ard.inWaiting()) # read all characters in buffer
    print ("Message from arduino: ")
    print (msg)
    i = i + 1
else:
    print "Exiting"
exit()

Here's the output of the above now:

$ python ardser.py
Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Python value sent:
63
Message from arduino:
Arduino received: 63
Arduino sends: 1


Exiting

How to Read from a Text File, Character by Character in C++

Assuming that temp is a char and textFile is a std::fstream derivative...

The syntax you're looking for is

textFile.get( temp );

Oracle get previous day records

I think you can also execute this command:

select (sysdate-1) PREVIOUS_DATE from dual;

Find a file with a certain extension in folder

You could use the Directory class

 Directory.GetFiles(path, "*.txt", SearchOption.AllDirectories)

Javascript getElementById based on a partial string

Given that what you want is to determine the full id of the element based upon just the prefix, you're going to have to do a search of the entire DOM (or at least, a search of an entire subtree if you know of some element that is always guaranteed to contain your target element). You can do this with something like:

function findChildWithIdLike(node, prefix) {
    if (node && node.id && node.id.indexOf(prefix) == 0) {
        //match found
        return node;
    }

    //no match, check child nodes
    for (var index = 0; index < node.childNodes.length; index++) {
        var child = node.childNodes[index];
        var childResult = findChildWithIdLike(child, prefix);
        if (childResult) {
            return childResult;
        }
    }
};

Here is an example: http://jsfiddle.net/xwqKh/

Be aware that dynamic element ids like the ones you are working with are typically used to guarantee uniqueness of element ids on a single page. Meaning that it is likely that there are multiple elements that share the same prefix. Probably you want to find them all.

If you want to find all of the elements that have a given prefix, instead of just the first one, you can use something like what is demonstrated here: http://jsfiddle.net/xwqKh/1/

Resizing an Image without losing any quality

See if you like the image resizing quality of this open source ASP.NET module. There's a live demo, so you can mess around with it yourself. It yields results that are (to me) impossible to distinguish from Photoshop output. It also has similar file sizes - MS did a good job on their JPEG encoder.

Angular: Cannot find a differ supporting object '[object Object]'

Missing square brackets around input property may cause this error. For example:

Component Foo {
    @Input()
    bars: BarType[];
}

Correct:

<app-foo [bars]="smth"></app-foo>

Incorrect (triggering error):

<app-foo bars="smth"></app-foo>

Using a custom (ttf) font in CSS

This is not a system font. this font is not supported in other systems. you can use font-face, convert font from this Site or from this

enter image description here

VBScript to send email without running Outlook

Yes. Blat or any other self contained SMTP mailer. Blat is a fairly full featured SMTP client that runs from command line

Blat is here

Select Pandas rows based on list index

Another way (although it is a longer code) but it is faster than the above codes. Check it using %timeit function:

df[df.index.isin([1,3])]

PS: You figure out the reason

enter image description here

Twitter API returns error 215, Bad Authentication Data

Try this twitter API explorer, you can sign in as a developer and query whatever you want.

Apache 2.4.3 (with XAMPP 1.8.1) not starting in windows 8

Skype is usually the culprit because it uses port 80 by default. Just close it or uncheck "Use port 80 and 443 as alternatives for incoming connections" under tools > options... > advanced > connection and then restart Skype.

How to map atan2() to degrees 0-360

Here's some javascript. Just input x and y values.

var angle = (Math.atan2(x,y) * (180/Math.PI) + 360) % 360;

If a DOM Element is removed, are its listeners also removed from memory?

Just extending other answers...

Delegated events handlers will not be removed upon element removal.

$('body').on('click', '#someEl', function (event){
  console.log(event);
});

$('#someEL').remove(); // removing the element from DOM

Now check:

$._data(document.body, 'events');

Convert int to string?

int num = 10;
string str = Convert.ToString(num);

add id to dynamically created <div>

Not sure if this is the best way, but it works.

if (cartDiv == null) {
    cartDiv = "<div id='unique_id'></div>"; // document.createElement('div');
    document.body.appendChild(cartDiv);
}

How to convert empty spaces into null values, using SQL Server?

here's a regex one for ya.

update table
set col1=null
where col1 not like '%[a-z,0-9]%'

essentially finds any columns that dont have letters or numbers in them and sets it to null. might have to update if you have columns with just special characters.

How to initialize an array's length in JavaScript?

The reason you shouldn't use new Array is demonstrated by this code:

var Array = function () {};

var x = new Array(4);

alert(x.length);  // undefined...

Some other code could mess with the Array variable. I know it's a bit far fetched that anyone would write such code, but still...

Also, as Felix King said, the interface is a little inconsistent, and could lead to some very difficult-to-track-down bugs.

If you wanted an array with length = x, filled with undefined (as new Array(x) would do), you could do this:

var x = 4;
var myArray = [];
myArray[x - 1] = undefined;

alert(myArray.length); // 4

change type of input field with jQuery

I guess you could use a background-image that contains the word "password" and change it back to an empty background-image on .focus().

.blur() ----> image with "password"

.focus() -----> image with no "password"

You could also do it with some CSS and jQuery. Have a text field show up exactly on top of the password field, hide() is on focus() and focus on the password field...

MatPlotLib: Multiple datasets on the same scatter plot

You need a reference to an Axes object to keep drawing on the same subplot.

import matplotlib.pyplot as plt

x = range(100)
y = range(100,200)
fig = plt.figure()
ax1 = fig.add_subplot(111)

ax1.scatter(x[:4], y[:4], s=10, c='b', marker="s", label='first')
ax1.scatter(x[40:],y[40:], s=10, c='r', marker="o", label='second')
plt.legend(loc='upper left');
plt.show()

enter image description here

AngularJS - $http.post send data as json

Use JSON.stringify() to wrap your json

var parameter = JSON.stringify({type:"user", username:user_email, password:user_password});
    $http.post(url, parameter).
    success(function(data, status, headers, config) {
        // this callback will be called asynchronously
        // when the response is available
        console.log(data);
      }).
      error(function(data, status, headers, config) {
        // called asynchronously if an error occurs
        // or server returns response with an error status.
      });

How to convert a List<String> into a comma separated string without iterating List explicitly

I am having ArrayList of String, which I need to convert to comma separated list, without space. The ArrayList toString() method adds square brackets, comma and space. I tried the Regular Expression method as under.

List<String> myProductList = new ArrayList<String>();
myProductList.add("sanjay");
myProductList.add("sameer");
myProductList.add("anand");
Log.d("TEST1", myProductList.toString());     // "[sanjay, sameer, anand]"
String patternString = myProductList.toString().replaceAll("[\\s\\[\\]]", "");
Log.d("TEST", patternString);                 // "sanjay,sameer,anand"

Please comment for more better efficient logic. ( The code is for Android / Java )

Thankx.

invalid operands of types int and double to binary 'operator%'

Because % is only defined for integer types. That's the modulus operator.

5.6.2 of the standard:

The operands of * and / shall have arithmetic or enumeration type; the operands of % shall have integral or enumeration type. [...]

As Oli pointed out, you can use fmod(). Don't forget to include math.h.

Is if(document.getElementById('something')!=null) identical to if(document.getElementById('something'))?

Cleanest version specially good if you just want to get the .value from the element.

document.getElementById('elementsid') ? function_if_exists(); function_if_doesnt_exists();

Pandas DataFrame Groupby two columns and get counts

You can just use the built-in function count follow by the groupby function

df.groupby(['col5','col2']).count()

How do I list loaded plugins in Vim?

:help local-additions

Lists local plugins added.

Convert a RGB Color Value to a Hexadecimal String

This is an adapted version of the answer given by Vivien Barousse with the update from Vulcan applied. In this example I use sliders to dynamically retreive the RGB values from three sliders and display that color in a rectangle. Then in method toHex() I use the values to create a color and display the respective Hex color code.

This example does not include the proper constraints for the GridBagLayout. Though the code will work, the display will look strange.

public class HexColor
{

  public static void main (String[] args)
  {
   JSlider sRed = new JSlider(0,255,1);
   JSlider sGreen = new JSlider(0,255,1);
   JSlider sBlue = new JSlider(0,255,1);
   JLabel hexCode = new JLabel();
   JPanel myPanel = new JPanel();
   GridBagLayout layout = new GridBagLayout();
   JFrame frame = new JFrame();

   //set frame to organize components using GridBagLayout 
   frame.setLayout(layout);

   //create gray filled rectangle 
   myPanel.paintComponent();
   myPanel.setBackground(Color.GRAY);

   //In practice this code is replicated and applied to sGreen and sBlue. 
   //For the sake of brevity I only show sRed in this post.
   sRed.addChangeListener(
         new ChangeListener()
         {
             @Override
             public void stateChanged(ChangeEvent e){
                 myPanel.setBackground(changeColor());
                 myPanel.repaint();
                 hexCode.setText(toHex());
         }
         }
     );
   //add each component to JFrame
   frame.add(myPanel);
   frame.add(sRed);
   frame.add(sGreen);
   frame.add(sBlue);
   frame.add(hexCode);
} //end of main

  //creates JPanel filled rectangle
  protected void paintComponent(Graphics g)
  {
      super.paintComponent(g);
      g.drawRect(360, 300, 10, 10);
      g.fillRect(360, 300, 10, 10);
  }

  //changes the display color in JPanel
  private Color changeColor()
  {
    int r = sRed.getValue();
    int b = sBlue.getValue();
    int g = sGreen.getValue();
    Color c;
    return  c = new Color(r,g,b);
  }

  //Displays hex representation of displayed color
  private String toHex()
  {
      Integer r = sRed.getValue();
      Integer g = sGreen.getValue();
      Integer b = sBlue.getValue();
      Color hC;
      hC = new Color(r,g,b);
      String hex = Integer.toHexString(hC.getRGB() & 0xffffff);
      while(hex.length() < 6){
          hex = "0" + hex;
      }
      hex = "Hex Code: #" + hex;
      return hex;
  }
}

A huge thank you to both Vivien and Vulcan. This solution works perfectly and was super simple to implement.

How can I add a table of contents to a Jupyter / JupyterLab notebook?

I recently created a small extension to Jupyter named jupyter-navbar. It searches for headers written in markdown cells, and displays links to them in the sidebar in a hierarchical fashion. The sidebar is resizable and collapsible. See screenshot below.

It is easy to install, and takes advantage of the 'custom' JS and CSS codes that get executed whenever a notebook is opened, so you don't need to manually run it.

enter image description here

PHP, display image with Header()

There is a better why to determine type of an image. with exif_imagetype

If you use this function, you can tell image's real extension.

with this function filename's extension is completely irrelevant, which is good.

function setHeaderContentType(string $filePath): void
{
    $numberToContentTypeMap = [
        '1' => 'image/gif',
        '2' => 'image/jpeg',
        '3' => 'image/png',
        '6' => 'image/bmp',
        '17' => 'image/ico'
    ];

    $contentType = $numberToContentTypeMap[exif_imagetype($filePath)] ?? null;
    
    if ($contentType === null) {
        throw new Exception('Unable to determine content type of file.');
    }

    header("Content-type: $contentType");
}

You can add more types from the link.

Hope it helps.

No Spring WebApplicationInitializer types detected on classpath

This turned out to be a stupid error. My log4j wasn't configured to capture my error output. I was throwing configuration errors in the background and once I fixed those I was good to go and my request mappings worked fine.

how to access parent window object using jquery?

Here is a more literal answer (parent window as opposed to opener) to the original question that can be used within an iframe, assuming the domain name in the iframe matches that of the parent window:

window.parent.$("#serverMsg")

jQuery send string as POST parameters

Not a direct answer to your question.. But following is the only syntax that used to work for me -

data: '{"winNumber": "' + win + '"}',

And the parameter-name match with the argument of the server method

Getting multiple values with scanf()

int a,b,c,d;
if(scanf("%d %d %d %d",&a,&b,&c,&d) == 4) {
   //read the 4 integers
} else {
   puts("Error. Please supply 4 integers");
}

node.js hash string?

Considering the thoughts from http://www.thoughtcrime.org/blog/the-cryptographic-doom-principle/ (in short: FIRST encrypt, THEN authenticate. Afterwards FIRST verify, THEN decrypt) I have implemented the following solution in node.js:

function encrypt(text,password){
  var cipher = crypto.createCipher(algorithm,password)
  var crypted = cipher.update(text,'utf8','hex')
  crypted += cipher.final('hex');
  return crypted;
}

function decrypt(text,password){
  var decipher = crypto.createDecipher(algorithm,password)
  var dec = decipher.update(text,'hex','utf8')
  dec += decipher.final('utf8');
  return dec;
}

function hashText(text){
    var hash = crypto.createHash('md5').update(text).digest("hex");
    //console.log(hash); 
    return hash;
}

function encryptThenAuthenticate(plainText,pw)
{
    var encryptedText = encrypt(plainText,pw);
    var hash = hashText(encryptedText);
    return encryptedText+"$"+hash;
}
function VerifyThenDecrypt(encryptedAndAuthenticatedText,pw)
{
    var encryptedAndHashArray = encryptedAndAuthenticatedText.split("$");
    var encrypted = encryptedAndHashArray[0];
    var hash = encryptedAndHashArray[1];
    var hash2Compare = hashText(encrypted);
    if (hash === hash2Compare)
    {
        return decrypt(encrypted,pw); 
    }
}

It can be tested with:

var doom = encryptThenAuthenticate("The encrypted text",user.cryptoPassword);
console.log(VerifyThenDecrypt(doom,user.cryptoPassword));

Hope this helps :-)

What is the proper use of an EventEmitter?

When you want to have cross component interaction, then you need to know what are @Input , @Output , EventEmitter and Subjects.

If the relation between components is parent- child or vice versa we use @input & @output with event emitter..

@output emits an event and you need to emit using event emitter.

If it's not parent child relationship.. then you have to use subjects or through a common service.

Running Windows batch file commands asynchronously

You can use the start command to spawn background processes without launching new windows:

start /b foo.exe

The new process will not be interruptable with CTRL-C; you can kill it only with CTRL-BREAK (or by closing the window, or via Task Manager.)

How to search images from private 1.0 registry in docker?

List all images

docker search <registry_host>:<registry_port>/

List images like 'vcs'

docker search <registry_host>:<registry_port>/vcs

How to pass optional arguments to a method in C++?

It might be interesting to some of you that in case of multiple default parameters:

void printValues(int x=10, int y=20, int z=30)
{
    std::cout << "Values: " << x << " " << y << " " << z << '\n';
}

Given the following function calls:

printValues(1, 2, 3);
printValues(1, 2);
printValues(1);
printValues();

The following output is produced:

Values: 1 2 3
Values: 1 2 30
Values: 1 20 30
Values: 10 20 30

Reference: http://www.learncpp.com/cpp-tutorial/77-default-parameters/

MySQL OPTIMIZE all tables?

A starter bash script to list and run a tool against the DBs...

#!/bin/bash

declare -a dbs
unset opt

for each in $(echo "show databases;" | mysql -u root) ;do

        dbs+=($each)

done



echo " The system found [ ${#dbs[@]} ] databases." ;sleep 2
echo
echo "press 1 to run a check"
echo "press 2 to run an optimization"
echo "press 3 to run a repair"
echo "press 4 to run check,repair, and optimization"
echo "press q to quit"
read input

case $input in
        1) opt="-c"
        ;;
        2) opt="-o"
        ;;
        3) opt="-r"
        ;;
        4) opt="--auto-repair -c -o"
        ;;
        *) echo "Quitting Application .."; exit 7
        ;;
esac

[[ -z $opt ]] && exit 7;

echo " running option:  mysqlcheck $opt in 5 seconds  on all Dbs... "; sleep 5

for ((i=0; i<${#dbs[@]}; i++)) ;do
        echo "${dbs[$i]} : "
        mysqlcheck $opt ${dbs[$i]}  -u root
    done

Authenticating against Active Directory with Java on Linux

I just finished a project that uses AD and Java. We used Spring ldapTemplate.

AD is LDAP compliant (almost), I don't think you will have any issues with the task you have. I mean the fact that it is AD or any other LDAP server it doesn't matter if you want just to connect.

I would take a look at: Spring LDAP

They have examples too.

As for encryption, we used SSL connection (so it was LDAPS). AD had to be configured on a SSL port/protocol.

But first of all, make sure you can properly connect to your AD via an LDAP IDE. I use Apache Directory Studio, it is really cool, and it is written in Java. That is all I needed. For testing purposes you could also install Apache Directory Server

Can a class member function template be virtual?

At least with gcc 5.4 virtual functions could be template members but has to be templates themselves.

#include <iostream>
#include <string>
class first {
protected:
    virtual std::string  a1() { return "a1"; }
    virtual std::string  mixt() { return a1(); }
};

class last {
protected:
    virtual std::string a2() { return "a2"; }
};

template<class T>  class mix: first , T {
    public:
    virtual std::string mixt() override;
};

template<class T> std::string mix<T>::mixt() {
   return a1()+" before "+T::a2();
}

class mix2: public mix<last>  {
    virtual std::string a1() override { return "mix"; }
};

int main() {
    std::cout << mix2().mixt();
    return 0;
}

Outputs

mix before a2
Process finished with exit code 0

php exec command (or similar) to not wait for result

You can run the command in the background by adding a & at the end of it as:

exec('run_baby_run &');

But doing this alone will hang your script because:

If a program is started with exec function, in order for it to continue running in the background, the output of the program must be redirected to a file or another output stream. Failing to do so will cause PHP to hang until the execution of the program ends.

So you can redirect the stdout of the command to a file, if you want to see it later or to /dev/null if you want to discard it as:

exec('run_baby_run > /dev/null &');

jQuery count child elements

You can use JavaScript (don't need jQuery)

document.querySelectorAll('#selected li').length;

How to unzip a file using the command line?

If you already have Java Development Kit on your PC and the bin directory is in your path (in most cases), you can use the command line:

jar xf test.zip

or if not in your path:

C:\Java\jdk1.6.0_03\bin>jar xf test.zip

Complete set of options for the jar tool available here.

Examples:

Extract jar file
    jar x[v]f jarfile [inputfiles] [-Joption] 
    jar x[v] [inputfiles] [-Joption]

TypeError: only integer scalar arrays can be converted to a scalar index with 1D numpy indices array

Perhaps the error message is somewhat misleading, but the gist is that X_train is a list, not a numpy array. You cannot use array indexing on it. Make it an array first:

out_images = np.array(X_train)[indices.astype(int)]

QString to char* conversion

The easiest way to convert a QString to char* is qPrintable(const QString& str), which is a macro expanding to str.toLocal8Bit().constData().

How to scroll the window using JQuery $.scrollTo() function

Actually something like

function scrollTo(prop){
    $('html,body').animate({scrollTop: $("#"+prop).offset().top +
 parseInt($("#"+prop).css('padding-top'),10) },'slow');
}

will work nicely and support padding. You can also support margins easily - for completion see below

function scrollTo(prop){
    $('html,body').animate({scrollTop: $("#"+prop).offset().top 
+ parseInt($("#"+prop).css('padding-top'),10) 
+ parseInt($("#"+prop).css('margin-top'),10) +},'slow');
}

When to use MongoDB or other document oriented database systems?

I would say use an RDBMS if you need complex transactions. Otherwise I would go with MongoDB - more flexible to work with and you know it can scale when you need to. (I'm biased though - I work on the MongoDB project)

Format JavaScript date as yyyy-mm-dd

formatDate(date) {
  const d = new Date(date)
  const ye = new Intl.DateTimeFormat('en', { year: 'numeric' }).format(d);
  const mo = new Intl.DateTimeFormat('en', { month: 'short' }).format(d);
  const da = new Intl.DateTimeFormat('en', { day: '2-digit' }).format(d);
  return `${da}-${mo}-${ye}`;
}

console.log("Formatated Date : ", formatDate("09/25/2020") )
// Output :: Formatated Date : 25-Sep-2020

How to count the number of occurrences of an element in a List

There is no native method in Java to do that for you. However, you can use IterableUtils#countMatches() from Apache Commons-Collections to do it for you.

Get length of array?

Compilating answers here and there, here's a complete set of arr tools to get the work done:

Function getArraySize(arr As Variant)
' returns array size for a n dimention array
' usage result(k) = size of the k-th dimension

Dim ndims As Long
Dim arrsize() As Variant
ndims = getDimensions(arr)
ReDim arrsize(ndims - 1)
For i = 1 To ndims
    arrsize(i - 1) = getDimSize(arr, i)
Next i
getArraySize = arrsize
End Function

Function getDimSize(arr As Variant, dimension As Integer)
' returns size for the given dimension number
    getDimSize = UBound(arr, dimension) - LBound(arr, dimension) + 1
End Function

Function getDimensions(arr As Variant) As Long
' returns number of dimension in an array (ex. sheet range = 2 dimensions)
    On Error GoTo Err
    Dim i As Long
    Dim tmp As Long
    i = 0
    Do While True
        i = i + 1
        tmp = UBound(arr, i)
    Loop
Err:
    getDimensions = i - 1
End Function

Fixed point vs Floating point number

From my understanding, fixed-point arithmetic is done using integers. where the decimal part is stored in a fixed amount of bits, or the number is multiplied by how many digits of decimal precision is needed.

For example, If the number 12.34 needs to be stored and we only need two digits of precision after the decimal point, the number is multiplied by 100 to get 1234. When performing math on this number, we'd use this rule set. Adding 5620 or 56.20 to this number would yield 6854 in data or 68.54.

If we want to calculate the decimal part of a fixed-point number, we use the modulo (%) operand.

12.34 (pseudocode):

v1 = 1234 / 100 // get the whole number
v2 = 1234 % 100 // get the decimal number (100ths of a whole).
print v1 + "." + v2 // "12.34"

Floating point numbers are a completely different story in programming. The current standard for floating point numbers use something like 23 bits for the data of the number, 8 bits for the exponent, and 1 but for sign. See this Wikipedia link for more information on this.

Creating an instance of class

  1. Allocates some dynamic memory from the free store, and creates an object in that memory using its default constructor. You never delete it, so the memory is leaked.
  2. Does exactly the same as 1; in the case of user-defined types, the parentheses are optional.
  3. Allocates some automatic memory, and creates an object in that memory using its default constructor. The memory is released automatically when the object goes out of scope.
  4. Similar to 3. Notionally, the named object foo4 is initialised by default-constructing, copying and destroying a temporary object; usually, this is elided giving the same result as 3.
  5. Allocates a dynamic object, then initialises a second by copying the first. Both objects are leaked; and there's no way to delete the first since you don't keep a pointer to it.
  6. Does exactly the same as 5.
  7. Does not compile. Foo foo5 is a declaration, not an expression; function (and constructor) arguments must be expressions.
  8. Creates a temporary object, and initialises a dynamic object by copying it. Only the dynamic object is leaked; the temporary is destroyed automatically at the end of the full expression. Note that you can create the temporary with just Foo() rather than the equivalent Foo::Foo() (or indeed Foo::Foo::Foo::Foo::Foo())

When do I use each?

  1. Don't, unless you like unnecessary decorations on your code.
  2. When you want to create an object that outlives the current scope. Remember to delete it when you've finished with it, and learn how to use smart pointers to control the lifetime more conveniently.
  3. When you want an object that only exists in the current scope.
  4. Don't, unless you think 3 looks boring and what to add some unnecessary decoration.
  5. Don't, because it leaks memory with no chance of recovery.
  6. Don't, because it leaks memory with no chance of recovery.
  7. Don't, because it won't compile
  8. When you want to create a dynamic Bar from a temporary Foo.

The number of method references in a .dex file cannot exceed 64k API 17

For me Upgrading Gradle works.Look for update at Android Website then add it in your build.gradle (Project) like this

 dependencies {
        classpath 'com.android.tools.build:gradle:2.2.0-alpha4'   
          ....
    }

then sync project with gradle file plus it might be happened sometimes because of java.exe (in my case) just force kill java.exe from task manager in windows then re run program

Make TextBox uneditable

Use the ReadOnly property on the TextBox.

myTextBox.ReadOnly = true;

But Remember: TextBoxBase.ReadOnly Property

When this property is set to true, the contents of the control cannot be changed by the user at runtime. With this property set to true, you can still set the value of the Text property in code. You can use this feature instead of disabling the control with the Enabled property to allow the contents to be copied and ToolTips to be shown.

Selecting multiple columns in a Pandas dataframe

I found this method to be very useful:

# iloc[row slicing, column slicing]
surveys_df.iloc [0:3, 1:4]

More details can be found here.

Just what is an IntPtr exactly?

Here's an example:

I'm writing a C# program that interfaces with a high-speed camera. The camera has its own driver that acquires images and loads them into the computer's memory for me automatically.

So when I'm ready to bring the latest image into my program to work with, the camera driver provides me with an IntPtr to where the image is ALREADY stored in physical memory, so I don't have to waste time/resources creating another block of memory to store an image that's in memory already. The IntPtr just shows me where the image already is.

What's the quickest way to multiply multiple cells by another number?

To multiply a column of numbers with a constant(same number), I have done like this.

Let C2 to C12 be different numbers which need to be multiplied by a single number (constant). Then type the numbers from C2 to C12.

In D2 type 1 (unity) and in E2 type formula =PRODUCT(C2:C12,CONSTANT). SELECT RIGHT ICON TO APPLY. NOW DRAG E2 THROUGH E12. YOU HAVE DONE IT.

C       D       E=PRODUCT(C2:C12,20)

25  1   500
30      600
35      700
40      800
45      900
50      1000
55      1100
60      1200
65      1300
70      1400
75      1500

How to use the gecko executable with Selenium

I'm using FirefoxOptions class to set the binary location with Firefox 52.0, GeckoDriver v0.15.0 and Selenium 3.3.1 as mentioned in this article - http://www.automationtestinghub.com/selenium-3-0-launch-firefox-with-geckodriver/

The java code that I used -

FirefoxOptions options = new FirefoxOptions();
options.setBinary("C:\\Program Files (x86)\\Mozilla Firefox\\firefox.exe"); //location of FF exe

FirefoxDriver driver = new FirefoxDriver(options);
driver.get("http://www.google.com");

How to read a .xlsx file using the pandas Library in iPython?

I usually create a dictionary containing a DataFrame for every sheet:

xl_file = pd.ExcelFile(file_name)

dfs = {sheet_name: xl_file.parse(sheet_name) 
          for sheet_name in xl_file.sheet_names}

Update: In pandas version 0.21.0+ you will get this behavior more cleanly by passing sheet_name=None to read_excel:

dfs = pd.read_excel(file_name, sheet_name=None)

In 0.20 and prior, this was sheetname rather than sheet_name (this is now deprecated in favor of the above):

dfs = pd.read_excel(file_name, sheetname=None)

Bootstrap datepicker disabling past dates without current date

To disable past dates & highlight today's date:

$(function () {
    $('.input-daterange').datepicker({
        startDate : new Date(),
        todayHighlight : true
    });
});

To disable future dates & highlight today's date:

$(function () {
    $('.input-daterange').datepicker({
        endDate : new Date(),
        todayHighlight : true
    });
});

For more details check this out https://bootstrap-datepicker.readthedocs.io/en/latest/options.html?highlight=startdate#quick-reference

$('body').on('click', '.anything', function(){})

You can try this:

You must follow the following format

    $('element,id,class').on('click', function(){....});

*JQuery code*

    $('body').addClass('.anything').on('click', function(){
      //do some code here i.e
      alert("ok");
    });

How can I debug javascript on Android?

Update: Remote Debugging

Previously, console logging was the best option for debugging JavaScript on Android. These days with Chrome for Android remote debugging, we are able to make use of all the goodness of the Chrome for Desktop Developer Tools on Android. Check out https://developers.google.com/chrome-developer-tools/docs/remote-debugging for more information.


Update: JavaScript Console

You can also navigate to about:debug in the URL bar to activate the debug menu and the JavaScript error console with recent Android devices. You should see SHOW JAVASCRIPT CONSOLE at the top of the Browser.

Currently in Android 4.0.3 (Ice Cream Sandwich), the logcat outputs to the browser channel. So you can filter using adb logcat browser:* *:S.


Original Answer

You can use the built in console JavaScript object to print log messages that you can review with adb logcat.

console.error('1');
console.info('2');
console.log('3');
console.warn('4')

Produces this output:

D/WebCore (  165): Console: 1 line: 0 source: http://...
D/WebCore (  165): Console: 2 line: 0 source: http://...
D/WebCore (  165): Console: 3 line: 0 source: http://...
D/WebCore (  165): Console: 4 line: 0 source: http://...

Determining the version of WebKit

If you type javascript:alert(navigator.userAgent) in the location bar you’ll see the WebKit version listed e.g.

In Chrome: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/532.2 (KHTML, like Gecko) Chrome/4.0.221.6 Safari/532.2

On Android Emulator Mozilla/5.0 (Linux; U; Android 1.6; en-us; sdk Build/DRC76) AppleWebKit/528.5+ (KHTML, like Gecko) Version/3.1.2 Mobile Safari/525.20.1

N.B.

Versions of WebKit that are not part of a Safari release have a + after the version number, and their version number is generally higher than the latest released version of WebKit. So, for example, 528+ is an unofficial build of WebKit that is newer than the 525.x version that shipped as part of Safari 3.1.2.

Spring Boot Program cannot find main class

I was facing the same problem. I have deleted the target folder and run maven install, it worked.

how to call a method in another Activity from Activity

The startActivityForResult pattern is much better suited for what you're trying to achieve : http://developer.android.com/reference/android/app/Activity.html#StartingActivities

Try below code

public class MainActivity extends Activity {  

    Button button1;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        textView1=(TextView)findViewById(R.id.textView1);  
        button1=(Button)findViewById(R.id.button1);  
        button1.setOnClickListener(new OnClickListener() {  
            @Override  
            public void onClick(View arg0) {  
                Intent intent=new Intent(MainActivity.this,SecondActivity.class);  
                startActivityForResult(intent, 2);// Activity is started with requestCode 2  
            }  
        });  
    }  
 // Call Back method  to get the Message form other Activity  
    @Override  
       protected void onActivityResult(int requestCode, int resultCode, Intent data)  
       {  
                 super.onActivityResult(requestCode, resultCode, data);  
                  // check if the request code is same as what is passed  here it is 2  
                   if(requestCode==2)  
                         {  
                          //do the things u wanted 
                         }  
     }  

} 

SecondActivity.class

public class SecondActivity extends Activity {  

    Button button1;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_second);  

            button1=(Button)findViewById(R.id.button1);  
            button1.setOnClickListener(new OnClickListener() {  
                @Override  
                public void onClick(View arg0) {  
                    String message="hello ";  
                    Intent intent=new Intent();  
                    intent.putExtra("MESSAGE",message);  
                    setResult(2,intent);  
                    finish();//finishing activity  
                }  
            });  
    }  

}  

Let me know if it helped...

Animate scroll to ID on page load

$(jQuery.browser.webkit ? "body": "html").animate({ scrollTop: $('#title1').offset().top }, 1000);

jquery-animate-body-for-all-browsers.

C++ pass an array by reference

Arrays can only be passed by reference, actually:

void foo(double (&bar)[10])
{
}

This prevents you from doing things like:

double arr[20];
foo(arr); // won't compile

To be able to pass an arbitrary size array to foo, make it a template and capture the size of the array at compile time:

template<typename T, size_t N>
void foo(T (&bar)[N])
{
    // use N here
}

You should seriously consider using std::vector, or if you have a compiler that supports c++11, std::array.

Does java have a int.tryparse that doesn't throw an exception for bad data?

Edit -- just saw your comment about the performance problems associated with a potentially bad piece of input data. I don't know offhand how try/catch on parseInt compares to a regex. I would guess, based on very little hard knowledge, that regexes are not hugely performant, compared to try/catch, in Java.

Anyway, I'd just do this:

public Integer tryParse(Object obj) {
  Integer retVal;
  try {
    retVal = Integer.parseInt((String) obj);
  } catch (NumberFormatException nfe) {
    retVal = 0; // or null if that is your preference
  }
  return retVal;
}

Create a tar.xz in one command

Try this: tar -cf file.tar file-to-compress ; xz -z file.tar

Note:

  1. tar.gz and tar.xz are not the same; xz provides better compression.
  2. Don't use pipe | because this runs commands simultaneously. Using ; or & executes commands one after another.

executing shell command in background from script

Building off of ngoozeff's answer, if you want to make a command run completely in the background (i.e., if you want to hide its output and prevent it from being killed when you close its Terminal window), you can do this instead:

cmd="google-chrome";
"${cmd}" &>/dev/null & disown;
  • &>/dev/null sets the command’s stdout and stderr to /dev/null instead of inheriting them from the parent process.
  • & makes the shell run the command in the background.
  • disown removes the “current” job, last one stopped or put in the background, from under the shell’s job control.

In some shells you can also use &! instead of & disown; they both have the same effect. Bash doesn’t support &!, though.

Also, when putting a command inside of a variable, it's more proper to use eval "${cmd}" rather than "${cmd}":

cmd="google-chrome";
eval "${cmd}" &>/dev/null & disown;

If you run this command directly in Terminal, it will show the PID of the process which the command starts. But inside of a shell script, no output will be shown.

Here's a function for it:

#!/bin/bash

# Run a command in the background.
_evalBg() {
    eval "$@" &>/dev/null & disown;
}

cmd="google-chrome";
_evalBg "${cmd}";

Also, see: Running bash commands in the background properly

Count number of tables in Oracle

select COUNT(*) from ALL_ALL_TABLES where OWNER='<Database-name>';

.....

Javascript add method to object

There are many ways to create re-usable objects like this in JavaScript. Mozilla have a nice introduction here:

The following will work in your example:

function Foo(){
    this.bar = function (){
        alert("Hello World!");
    }
}

myFoo = new Foo();
myFoo.bar(); // Hello World?????????????????????????????????

Where is Python language used?

Python is also great for scientific programs such as statistical models or physics sims. I've done monte-carlo programs and, using the VISUAL module, a 3D simulation of the Apollo mission.

How can I get the value of a registry key from within a batch script?

With regedit:

@echo off
setlocal
::if the scrit is not ran as administrator
::  and the key does not require admin permissions
set __COMPAT_LAYER=RunAsInvoker

set "key=%~1"
set "value=%~2"

regedit /e "#.reg" "%key%"


for /f "tokens=1,* delims==" %%a in ('find  """%value%""=" "#.reg"') do if "%%~b" neq "" echo %%~b
del /q #.reg

endlocal

Example:

call regreader.bat "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.0\Setup\1033\" Version

output:

3.0.30729.4926