Programs & Examples On #Resourceproviderfactory

SELECT * FROM multiple tables. MySQL

What you do here is called a JOIN (although you do it implicitly because you select from multiple tables). This means, if you didn't put any conditions in your WHERE clause, you had all combinations of those tables. Only with your condition you restrict your join to those rows where the drink id matches.

But there are still X multiple rows in the result for every drink, if there are X photos with this particular drinks_id. Your statement doesn't restrict which photo(s) you want to have!

If you only want one row per drink, you have to tell SQL what you want to do if there are multiple rows with a particular drinks_id. For this you need grouping and an aggregate function. You tell SQL which entries you want to group together (for example all equal drinks_ids) and in the SELECT, you have to tell which of the distinct entries for each grouped result row should be taken. For numbers, this can be average, minimum, maximum (to name some).

In your case, I can't see the sense to query the photos for drinks if you only want one row. You probably thought you could have an array of photos in your result for each drink, but SQL can't do this. If you only want any photo and you don't care which you'll get, just group by the drinks_id (in order to get only one row per drink):

SELECT name, price, photo
FROM drinks, drinks_photos
WHERE drinks.id = drinks_id 
GROUP BY drinks_id

name     price   photo
fanta    5       ./images/fanta-1.jpg
dew      4       ./images/dew-1.jpg

In MySQL, we also have GROUP_CONCAT, if you want the file names to be concatenated to one single string:

SELECT name, price, GROUP_CONCAT(photo, ',')
FROM drinks, drinks_photos
WHERE drinks.id = drinks_id 
GROUP BY drinks_id

name     price   photo
fanta    5       ./images/fanta-1.jpg,./images/fanta-2.jpg,./images/fanta-3.jpg
dew      4       ./images/dew-1.jpg,./images/dew-2.jpg

However, this can get dangerous if you have , within the field values, since most likely you want to split this again on the client side. It is also not a standard SQL aggregate function.

COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better?

Two of them always produce the same answer:

  • COUNT(*) counts the number of rows
  • COUNT(1) also counts the number of rows

Assuming the pk is a primary key and that no nulls are allowed in the values, then

  • COUNT(pk) also counts the number of rows

However, if pk is not constrained to be not null, then it produces a different answer:

  • COUNT(possibly_null) counts the number of rows with non-null values in the column possibly_null.

  • COUNT(DISTINCT pk) also counts the number of rows (because a primary key does not allow duplicates).

  • COUNT(DISTINCT possibly_null_or_dup) counts the number of distinct non-null values in the column possibly_null_or_dup.

  • COUNT(DISTINCT possibly_duplicated) counts the number of distinct (necessarily non-null) values in the column possibly_duplicated when that has the NOT NULL clause on it.

Normally, I write COUNT(*); it is the original recommended notation for SQL. Similarly, with the EXISTS clause, I normally write WHERE EXISTS(SELECT * FROM ...) because that was the original recommend notation. There should be no benefit to the alternatives; the optimizer should see through the more obscure notations.

How to send password securely over HTTP?

Using https sounds best option here (certificates are not that expensive nowadays). However if http is a requirement, you may use some encription - encript it on server side and decript in users browser (send key separately).

We have used that while implementing safevia.net - encription is done on clients (sender/receiver) sides, so users data are not available on network nor server layer.

How do I edit a file after I shell to a Docker container?

You can open existing file with

cat filename.extension

and copy all the existing text on clipboard.

Then delete old file with

rm filename.extension

or rename old file with

mv old-filename.extension new-filename.extension

Create new file with

cat > new-file.extension

Then paste all text copied on clipboard, press Enter and exit with save by pressing ctrl+z. And voila no need to install any kind of editors.

findViewByID returns null

It crashed for me because one of fields in my activity id was matching with id in an other activity. I fixed it by giving a unique id.

In my loginActivity.xml password field id was "password". In my registration activity I just fixed it by giving id r_password, then it returned not null object:

password = (EditText)findViewById(R.id.r_password);

Execute a terminal command from a Cocoa app

Custos Mortem said:

I'm surprised no one really got into blocking/non-blocking call issues

For blocking/non-blocking call issues regarding NSTask read below:

asynctask.m -- sample code that shows how to implement asynchronous stdin, stdout & stderr streams for processing data with NSTask

Source code of asynctask.m is available at GitHub.

How do I install SciPy on 64 bit Windows?

I haven't tried it, but you may want to download this version of Portable Python. It comes with Scipy-0.7.0b1 running on Python 2.5.4.

Rotate a div using javascript

To rotate a DIV we can add some CSS that, well, rotates the DIV using CSS transform rotate.

To toggle the rotation we can keep a flag, a simple variable with a boolean value that tells us what way to rotate.

var rotated = false;

document.getElementById('button').onclick = function() {
    var div = document.getElementById('div'),
        deg = rotated ? 0 : 66;

    div.style.webkitTransform = 'rotate('+deg+'deg)'; 
    div.style.mozTransform    = 'rotate('+deg+'deg)'; 
    div.style.msTransform     = 'rotate('+deg+'deg)'; 
    div.style.oTransform      = 'rotate('+deg+'deg)'; 
    div.style.transform       = 'rotate('+deg+'deg)'; 

    rotated = !rotated;
}

_x000D_
_x000D_
var rotated = false;_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
    var div = document.getElementById('div'),_x000D_
        deg = rotated ? 0 : 66;_x000D_
_x000D_
    div.style.webkitTransform = 'rotate('+deg+'deg)'; _x000D_
    div.style.mozTransform    = 'rotate('+deg+'deg)'; _x000D_
    div.style.msTransform     = 'rotate('+deg+'deg)'; _x000D_
    div.style.oTransform      = 'rotate('+deg+'deg)'; _x000D_
    div.style.transform       = 'rotate('+deg+'deg)'; _x000D_
    _x000D_
    rotated = !rotated;_x000D_
}
_x000D_
#div {_x000D_
    position:relative; _x000D_
    height: 200px; _x000D_
    width: 200px; _x000D_
    margin: 30px;_x000D_
    background: red;_x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_

To add some animation to the rotation all we have to do is add CSS transitions

div {
    -webkit-transition: all 0.5s ease-in-out;
    -moz-transition: all 0.5s ease-in-out;
    -o-transition: all 0.5s ease-in-out;
    transition: all 0.5s ease-in-out;
}

_x000D_
_x000D_
var rotated = false;_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
    var div = document.getElementById('div'),_x000D_
        deg = rotated ? 0 : 66;_x000D_
_x000D_
    div.style.webkitTransform = 'rotate('+deg+'deg)'; _x000D_
    div.style.mozTransform    = 'rotate('+deg+'deg)'; _x000D_
    div.style.msTransform     = 'rotate('+deg+'deg)'; _x000D_
    div.style.oTransform      = 'rotate('+deg+'deg)'; _x000D_
    div.style.transform       = 'rotate('+deg+'deg)'; _x000D_
    _x000D_
    rotated = !rotated;_x000D_
}
_x000D_
#div {_x000D_
    position:relative; _x000D_
    height: 200px; _x000D_
    width: 200px; _x000D_
    margin: 30px;_x000D_
    background: red;_x000D_
    -webkit-transition: all 0.5s ease-in-out;_x000D_
    -moz-transition: all 0.5s ease-in-out;_x000D_
    -o-transition: all 0.5s ease-in-out;_x000D_
    transition: all 0.5s ease-in-out;_x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_

Another way to do it is using classes, and setting all the styles in a stylesheet, thus keeping them out of the javascript

document.getElementById('button').onclick = function() {
    document.getElementById('div').classList.toggle('rotated');
}

_x000D_
_x000D_
document.getElementById('button').onclick = function() {_x000D_
    document.getElementById('div').classList.toggle('rotated');_x000D_
}
_x000D_
#div {_x000D_
    position:relative; _x000D_
    height: 200px; _x000D_
    width: 200px; _x000D_
    margin: 30px;_x000D_
    background: red;_x000D_
    -webkit-transition: all 0.5s ease-in-out;_x000D_
    -moz-transition: all 0.5s ease-in-out;_x000D_
    -o-transition: all 0.5s ease-in-out;_x000D_
    transition: all 0.5s ease-in-out;_x000D_
}_x000D_
_x000D_
#div.rotated {_x000D_
    -webkit-transform : rotate(66deg); _x000D_
    -moz-transform : rotate(66deg); _x000D_
    -ms-transform : rotate(66deg); _x000D_
    -o-transform : rotate(66deg); _x000D_
    transform : rotate(66deg); _x000D_
}
_x000D_
<button id="button">rotate</button>_x000D_
<br /><br />_x000D_
<div id="div"></div>
_x000D_
_x000D_
_x000D_

How to elegantly check if a number is within a range?

When checking if a "Number" is in a range you have to be clear in what you mean, and what does two numbers are equal mean? In general you should wrap all floating point numbers in what is called a 'epsilon ball' this is done by picking some small value and saying if two values are this close they are the same thing.

    private double _epsilon = 10E-9;
    /// <summary>
    /// Checks if the distance between two doubles is within an epsilon.
    /// In general this should be used for determining equality between doubles.
    /// </summary>
    /// <param name="x0">The orgin of intrest</param>
    /// <param name="x"> The point of intrest</param>
    /// <param name="epsilon">The minimum distance between the points</param>
    /// <returns>Returns true iff x  in (x0-epsilon, x0+epsilon)</returns>
    public static bool IsInNeghborhood(double x0, double x, double epsilon) => Abs(x0 - x) < epsilon;

    public static bool AreEqual(double v0, double v1) => IsInNeghborhood(v0, v1, _epsilon);

With these two helpers in place and assuming that if any number can be cast as a double without the required accuracy. All you will need now is an enum and another method

    public enum BoundType
    {
        Open,
        Closed,
        OpenClosed,
        ClosedOpen
    }

The other method follows:

    public static bool InRange(double value, double upperBound, double lowerBound, BoundType bound = BoundType.Open)
    {
        bool inside = value < upperBound && value > lowerBound;
        switch (bound)
        {
            case BoundType.Open:
                return inside;
            case BoundType.Closed:
                return inside || AreEqual(value, upperBound) || AreEqual(value, lowerBound); 
            case BoundType.OpenClosed:
                return inside || AreEqual(value, upperBound);
            case BoundType.ClosedOpen:
                return inside || AreEqual(value, lowerBound);
            default:
                throw new System.NotImplementedException("You forgot to do something");
        }
    }

Now this may be far more than what you wanted, but it keeps you from dealing with rounding all the time and trying to remember if a value has been rounded and to what place. If you need to you can easily extend this to work with any epsilon and to allow your epsilon to change.

How can I recover the return value of a function passed to multiprocessing.Process?

Use shared variable to communicate. For example like this:

import multiprocessing


def worker(procnum, return_dict):
    """worker function"""
    print(str(procnum) + " represent!")
    return_dict[procnum] = procnum


if __name__ == "__main__":
    manager = multiprocessing.Manager()
    return_dict = manager.dict()
    jobs = []
    for i in range(5):
        p = multiprocessing.Process(target=worker, args=(i, return_dict))
        jobs.append(p)
        p.start()

    for proc in jobs:
        proc.join()
    print(return_dict.values())

I want to get the type of a variable at runtime

So, strictly speaking, the "type of a variable" is always present, and can be passed around as a type parameter. For example:

val x = 5
def f[T](v: T) = v
f(x) // T is Int, the type of x

But depending on what you want to do, that won't help you. For instance, may want not to know what is the type of the variable, but to know if the type of the value is some specific type, such as this:

val x: Any = 5
def f[T](v: T) = v match {
  case _: Int    => "Int"
  case _: String => "String"
  case _         => "Unknown"
}
f(x)

Here it doesn't matter what is the type of the variable, Any. What matters, what is checked is the type of 5, the value. In fact, T is useless -- you might as well have written it def f(v: Any) instead. Also, this uses either ClassTag or a value's Class, which are explained below, and cannot check the type parameters of a type: you can check whether something is a List[_] (List of something), but not whether it is, for example, a List[Int] or List[String].

Another possibility is that you want to reify the type of the variable. That is, you want to convert the type into a value, so you can store it, pass it around, etc. This involves reflection, and you'll be using either ClassTag or a TypeTag. For example:

val x: Any = 5
import scala.reflect.ClassTag
def f[T](v: T)(implicit ev: ClassTag[T]) = ev.toString
f(x) // returns the string "Any"

A ClassTag will also let you use type parameters you received on match. This won't work:

def f[A, B](a: A, b: B) = a match {
  case _: B => "A is a B"
  case _ => "A is not a B"
}

But this will:

val x = 'c'
val y = 5
val z: Any = 5
import scala.reflect.ClassTag
def f[A, B: ClassTag](a: A, b: B) = a match {
  case _: B => "A is a B"
  case _ => "A is not a B"
}
f(x, y) // A (Char) is not a B (Int)
f(x, z) // A (Char) is a B (Any)

Here I'm using the context bounds syntax, B : ClassTag, which works just like the implicit parameter in the previous ClassTag example, but uses an anonymous variable.

One can also get a ClassTag from a value's Class, like this:

val x: Any = 5
val y = 5
import scala.reflect.ClassTag
def f(a: Any, b: Any) = {
  val B = ClassTag(b.getClass)
  ClassTag(a.getClass) match {
    case B => "a is the same class as b"
    case _ => "a is not the same class as b"
  }
}
f(x, y) == f(y, x) // true, a is the same class as b

A ClassTag is limited in that it only covers the base class, but not its type parameters. That is, the ClassTag for List[Int] and List[String] is the same, List. If you need type parameters, then you must use a TypeTag instead. A TypeTag however, cannot be obtained from a value, nor can it be used on a pattern match, due to JVM's erasure.

Examples with TypeTag can get quite complex -- not even comparing two type tags is not exactly simple, as can be seen below:

import scala.reflect.runtime.universe.TypeTag
def f[A, B](a: A, b: B)(implicit evA: TypeTag[A], evB: TypeTag[B]) = evA == evB
type X = Int
val x: X = 5
val y = 5
f(x, y) // false, X is not the same type as Int

Of course, there are ways to make that comparison return true, but it would require a few book chapters to really cover TypeTag, so I'll stop here.

Finally, maybe you don't care about the type of the variable at all. Maybe you just want to know what is the class of a value, in which case the answer is rather simple:

val x = 5
x.getClass // int -- technically, an Int cannot be a class, but Scala fakes it

It would be better, however, to be more specific about what you want to accomplish, so that the answer can be more to the point.

Saving the PuTTY session logging

This is a bit confusing, but follow these steps to save the session.

  1. Category -> Session -> enter public IP in Host and 22 in port.
  2. Connection -> SSH -> Auth -> select the .ppk file
  3. Category -> Session -> enter a name in Saved Session -> Click Save

To open the session, double click on particular saved session.

How can I find all matches to a regular expression in Python?

Use re.findall or re.finditer instead.

re.findall(pattern, string) returns a list of matching strings.

re.finditer(pattern, string) returns an iterator over MatchObject objects.

Example:

re.findall( r'all (.*?) are', 'all cats are smarter than dogs, all dogs are dumber than cats')
# Output: ['cats', 'dogs']

[x.group() for x in re.finditer( r'all (.*?) are', 'all cats are smarter than dogs, all dogs are dumber than cats')]
# Output: ['all cats are', 'all dogs are']

Boolean vs boolean in Java

You can use Boolean / boolean. Simplicity is the way to go. If you do not need specific api (Collections, Streams, etc.) and you are not foreseeing that you will need them - use primitive version of it (boolean).

  1. With primitives you guarantee that you will not pass null values.
    You will not fall in traps like this. The code below throws NullPointerException (from: Booleans, conditional operators and autoboxing):

    public static void main(String[] args) throws Exception { Boolean b = true ? returnsNull() : false; // NPE on this line. System.out.println(b); } public static Boolean returnsNull() { return null; }

  2. Use Boolean when you need an object, eg:

    • Stream of Booleans,
    • Optional
    • Collections of Booleans

git status shows fatal: bad object HEAD

I managed to fix a similar problem to this when some of git's files were corrupted:

https://stackoverflow.com/a/30871926/1737957

In my answer on that question, look for the part where I had the same error message as here:

fatal: bad object HEAD.

You could try following what I did from that point on. Make sure to back up the whole folder first.

Of course, your repository might be corrupted in a completely different way, and what I did won't solve your problem. But it might give you some ideas! Git internals seem like magic, but it's really just a bunch of files which can be edited, moved, deleted the same as any others. Once you have a good idea of what they do and how they fit together you have a good chance of success.

Open youtube video in Fancybox jquery

Thanx, Alexander!

And to set the fancy-close button above the youtube's flash-content add 'wmode' to 'swf' parameters:

'swf': {'allowfullscreen':'true', 'wmode':'transparent'}

How to display full (non-truncated) dataframe information in html when converting from pandas dataframe to html?

pd.set_option('display.max_columns', None)  

id (second argument) can fully show the columns.

How to specify "does not contain" in dplyr filter

Note that %in% returns a logical vector of TRUE and FALSE. To negate it, you can use ! in front of the logical statement:

SE_CSVLinelist_filtered <- filter(SE_CSVLinelist_clean, 
 !where_case_travelled_1 %in% 
   c('Outside Canada','Outside province/territory of residence but within Canada'))

Regarding your original approach with -c(...), - is a unary operator that "performs arithmetic on numeric or complex vectors (or objects which can be coerced to them)" (from help("-")). Since you are dealing with a character vector that cannot be coerced to numeric or complex, you cannot use -.

How to remove folders with a certain name

If the target directory is empty, use find, filter with only directories, filter by name, execute rmdir:

find . -type d -name a -exec rmdir {} \;

If you want to recursively delete its contents, replace -exec rmdir {} \; with -delete or -prune -exec rm -rf {} \;. Other answers include details about these versions, credit them too.

How do I force my .NET application to run as administrator?

Right click your executable, go to Properties > Compatibility and check the 'Run this program as admin' box.

If you want to run it as admin for all users, do the same thing in 'change setting for all users'.

Using Razor within JavaScript

There is also one more option than @: and <text></text>.

Using <script> block itself.

When you need to do large chunks of JavaScript depending on Razor code, you can do it like this:

@if(Utils.FeatureEnabled("Feature")) {
    <script>
        // If this feature is enabled
    </script>
}

<script>
    // Other JavaScript code
</script>

Pros of this manner is that it doesn't mix JavaScript and Razor too much, because mixing them a lot will cause readability issues eventually. Also large text blocks are not very readable either.

View's SELECT contains a subquery in the FROM clause

create view view_clients_credit_usage as
    select client_id, sum(credits_used) as credits_used 
    from credit_usage 
    group by client_id

create view view_credit_status as 
    select 
        credit_orders.client_id, 
        sum(credit_orders.number_of_credits) as purchased, 
        ifnull(t1.credits_used,0) as used 
    from credit_orders
    left outer join view_clients_credit_usage as t1 on t1.client_id = credit_orders.client_id
    where credit_orders.payment_status='Paid'
    group by credit_orders.client_id)

generate random string for div id

i like this simple one:

function randstr(prefix)
{
    return Math.random().toString(36).replace('0.',prefix || '');
}

since id should (though not must) start with a letter, i'd use it like this:

let div_id = randstr('youtube_div_');

some example values:

youtube_div_4vvbgs01076
youtube_div_1rofi36hslx
youtube_div_i62wtpptnpo
youtube_div_rl4fc05xahs
youtube_div_jb9bu85go7
youtube_div_etmk8u7a3r9
youtube_div_7jrzty7x4ft
youtube_div_f41t3hxrxy
youtube_div_8822fmp5sc8
youtube_div_bv3a3flv425

python inserting variable string as file name

And with the new string formatting method...

f = open('{0}.csv'.format(name), 'wb')

Convert a python UTC datetime to a local datetime using only python standard library?

Here is another way to change timezone in datetime format (I know I wasted my energy on this but I didn't see this page so I don't know how) without min. and sec. cause I don't need it for my project:

def change_time_zone(year, month, day, hour):
      hour = hour + 7 #<-- difference
      if hour >= 24:
        difference = hour - 24
        hour = difference
        day += 1
        long_months = [1, 3, 5, 7, 8, 10, 12]
        short_months = [4, 6, 9, 11]
        if month in short_months:
          if day >= 30:
            day = 1
            month += 1
            if month > 12:
              year += 1
        elif month in long_months:
          if day >= 31:
            day = 1
            month += 1
            if month > 12:
              year += 1
        elif month == 2:
          if not year%4==0:
            if day >= 29:
              day = 1
              month += 1
              if month > 12:
                year += 1
          else:
            if day >= 28:
              day = 1
              month += 1
              if month > 12:
                year += 1
      return datetime(int(year), int(month), int(day), int(hour), 00)

Is it possible to start a shell session in a running container (without ssh)

With docker 1.3, there is a new command docker exec. This allows you to enter a running docker:

docker exec -it "id of running container" bash

Generating 8-character only UUIDs

As @Cephalopod stated it isn't possible but you can shorten a UUID to 22 characters

public static String encodeUUIDBase64(UUID uuid) {
        ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
        bb.putLong(uuid.getMostSignificantBits());
        bb.putLong(uuid.getLeastSignificantBits());
        return StringUtils.trimTrailingCharacter(BaseEncoding.base64Url().encode(bb.array()), '=');
}

Get the directory from a file path in java (android)

I have got solution on this after 4 days, Please note following points while giving path to File class in Android(Java):

  1. Use path for internal storage String path="/storage/sdcard0/myfile.txt";
  2. path="/storage/sdcard1/myfile.txt";
  3. mention permissions in Manifest file.

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

  4. First check file length for confirmation.
  5. Check paths in ES File Explorer regarding sdcard0 & sdcard1 is this same or else......

e.g.

File file=new File(path);
long=file.length();//in Bytes

CSS two divs next to each other

The method suggested by @roe and @MohitNanda work, but if the right div is set as float:right;, then it must come first in the HTML source. This breaks the left-to-right read order, which could be confusing if the page is displayed with styles turned off. If that's the case, it might be better to use a wrapper div and absolute positioning:

<div id="wrap" style="position:relative;">
    <div id="left" style="margin-right:201px;border:1px solid red;">left</div>
    <div id="right" style="position:absolute;width:200px;right:0;top:0;border:1px solid blue;">right</div>
</div>

Demonstrated:

left right

Edit: Hmm, interesting. The preview window shows the correctly formatted divs, but the rendered post item does not. Sorry then, you'll have to try it for yourself.

Reliable way for a Bash script to get the full path to itself

You may try to define the following variable:

CWD="$(cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"

Or you can try the following function in Bash:

realpath () {
  [[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
}

This function takes one argument. If the argument already has an absolute path, print it as it is, otherwise print $PWD variable + filename argument (without ./ prefix).

Related:

Does adding a duplicate value to a HashSet/HashMap replace the previous value

In the case of HashMap, it replaces the old value with the new one.

In the case of HashSet, the item isn't inserted.

Best way to test if a row exists in a MySQL table

I'd go with COUNT(1). It is faster than COUNT(*) because COUNT(*) tests to see if at least one column in that row is != NULL. You don't need that, especially because you already have a condition in place (the WHERE clause). COUNT(1) instead tests the validity of 1, which is always valid and takes a lot less time to test.

Playing Sound In Hidden Tag

That's how I achieved it, which is not visible (HORRIBLE SOUND....)

<!-- horrible is your mp3 file name any other supported format.-->
<audio controls autoplay hidden="" src="horrible.mp3" type ="audio/mp3"">your browser does not support Html5</audio>

Why do people use Heroku when AWS is present? What distinguishes Heroku from AWS?

Even though both AWS and Heroku are cloud platforms, they are different as AWS is IaaS and Heroku is PaaS

How to exit git log or git diff

You can press q to exit.

git hist is using a pager tool so you can scroll up and down the results before returning to the console.

How to display a pdf in a modal window?

You can have a look at this library: https://github.com/mozilla/pdf.js it renders PDF document in a Web/HTML page

Also you can use Flash to embed the document into any HTML page like that:

<object data="your_file.pdf#view=Fit" type="application/pdf" width="100%" height="850">
    <p>
        It appears your Web browser is not configured to display PDF files. No worries, just <a href="your_file.pdf">click here to download the PDF file.</a>
    </p>
</object>

Border length smaller than div width?

I just accomplished the opposite of this using :after and ::after because I needed to make my bottom border exactly 1.3rem wider:

My element got super deformed when I used :before and :after at the same time because the elements are horizontally aligned with display: flex, flex-direction: row and align-items: center.

You could use this for making something wider or narrower, or probably any mathematical dimension mods:

a.nav_link-active {
  color: $e1-red;
  margin-top: 3.7rem;
}
a.nav_link-active:visited {
  color: $e1-red;
}
a.nav_link-active:after {
  content: '';
  margin-top: 3.3rem;      // margin and height should
  height: 0.4rem;          // add up to active link margin
  background: $e1-red;
  margin-left: -$nav-spacer-margin;
  display: block;
}
a.nav_link-active::after {
  content: '';
  margin-top: 3.3rem;      // margin and height should
  height: 0.4rem;          // add up to active link margin
  background: $e1-red;
  margin-right: -$nav-spacer-margin;
  display: block;
}

Sorry, this is SCSS, just multiply the numbers by 10 and change the variables with some normal values.

How to add elements of a Java8 stream into an existing List

NOTE: nosid's answer shows how to add to an existing collection using forEachOrdered(). This is a useful and effective technique for mutating existing collections. My answer addresses why you shouldn't use a Collector to mutate an existing collection.

The short answer is no, at least, not in general, you shouldn't use a Collector to modify an existing collection.

The reason is that collectors are designed to support parallelism, even over collections that aren't thread-safe. The way they do this is to have each thread operate independently on its own collection of intermediate results. The way each thread gets its own collection is to call the Collector.supplier() which is required to return a new collection each time.

These collections of intermediate results are then merged, again in a thread-confined fashion, until there is a single result collection. This is the final result of the collect() operation.

A couple answers from Balder and assylias have suggested using Collectors.toCollection() and then passing a supplier that returns an existing list instead of a new list. This violates the requirement on the supplier, which is that it return a new, empty collection each time.

This will work for simple cases, as the examples in their answers demonstrate. However, it will fail, particularly if the stream is run in parallel. (A future version of the library might change in some unforeseen way that will cause it to fail, even in the sequential case.)

Let's take a simple example:

List<String> destList = new ArrayList<>(Arrays.asList("foo"));
List<String> newList = Arrays.asList("0", "1", "2", "3", "4", "5");
newList.parallelStream()
       .collect(Collectors.toCollection(() -> destList));
System.out.println(destList);

When I run this program, I often get an ArrayIndexOutOfBoundsException. This is because multiple threads are operating on ArrayList, a thread-unsafe data structure. OK, let's make it synchronized:

List<String> destList =
    Collections.synchronizedList(new ArrayList<>(Arrays.asList("foo")));

This will no longer fail with an exception. But instead of the expected result:

[foo, 0, 1, 2, 3]

it gives weird results like this:

[foo, 2, 3, foo, 2, 3, 1, 0, foo, 2, 3, foo, 2, 3, 1, 0, foo, 2, 3, foo, 2, 3, 1, 0, foo, 2, 3, foo, 2, 3, 1, 0]

This is the result of the thread-confined accumulation/merging operations I described above. With a parallel stream, each thread calls the supplier to get its own collection for intermediate accumulation. If you pass a supplier that returns the same collection, each thread appends its results to that collection. Since there is no ordering among the threads, results will be appended in some arbitrary order.

Then, when these intermediate collections are merged, this basically merges the list with itself. Lists are merged using List.addAll(), which says that the results are undefined if the source collection is modified during the operation. In this case, ArrayList.addAll() does an array-copy operation, so it ends up duplicating itself, which is sort-of what one would expect, I guess. (Note that other List implementations might have completely different behavior.) Anyway, this explains the weird results and duplicated elements in the destination.

You might say, "I'll just make sure to run my stream sequentially" and go ahead and write code like this

stream.collect(Collectors.toCollection(() -> existingList))

anyway. I'd recommend against doing this. If you control the stream, sure, you can guarantee that it won't run in parallel. I expect that a style of programming will emerge where streams get handed around instead of collections. If somebody hands you a stream and you use this code, it'll fail if the stream happens to be parallel. Worse, somebody might hand you a sequential stream and this code will work fine for a while, pass all tests, etc. Then, some arbitrary amount of time later, code elsewhere in the system might change to use parallel streams which will cause your code to break.

OK, then just make sure to remember to call sequential() on any stream before you use this code:

stream.sequential().collect(Collectors.toCollection(() -> existingList))

Of course, you'll remember to do this every time, right? :-) Let's say you do. Then, the performance team will be wondering why all their carefully crafted parallel implementations aren't providing any speedup. And once again they'll trace it down to your code which is forcing the entire stream to run sequentially.

Don't do it.

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

There's no method in the JDK for this that I'm aware of. Apache Commons Lang has various overloaded join() methods in the StringUtils class that do what you want.

ModelState.IsValid == false, why?

As you are probably programming in Visual studio you'd better take advantage of the possibility of using breakpoints for such easy debugging steps (getting an idea what the problem is as in your case). Just place them just in front / at the place where you check ModelState.isValid and hover over the ModelState. Now you can easily browse through all the values inside and see what error causes the isvalid return false.

modelstate

Can I use Objective-C blocks as properties?

Hello, Swift

Complementing what @Francescu answered.

Adding extra parameters:

func test(function:String -> String, param1:String, param2:String) -> String
{
    return function("test"+param1 + param2)
}

func funcStyle(s:String) -> String
{
    return "FUNC__" + s + "__FUNC"
}
let resultFunc = test(funcStyle, "parameter 1", "parameter 2")

let blockStyle:(String) -> String = {s in return "BLOCK__" + s + "__BLOCK"}
let resultBlock = test(blockStyle, "parameter 1", "parameter 2")

let resultAnon = test({(s:String) -> String in return "ANON_" + s + "__ANON" }, "parameter 1", "parameter 2")


println(resultFunc)
println(resultBlock)
println(resultAnon)

jQuery Loop through each div

$('div.target').each(function() {
   /* Measure the width of each image. */
   var test = $(this).find('.scrolling img').width();

   /* Find out how many images there are. */
   var testimg = $(this).find('.scrolling img').length;

   /* Do the maths. */
   var final = (test* testimg)*1.2;

   /* Apply the maths to the CSS. */
   $(this).find('scrolling').width(final); 
});

Here you loop through all your div's with class target and you do the calculations. Within this loop you can simply use $(this) to indicate the currently selected <div> tag.

count of entries in data frame in R

I think of this as a two-step process:

  1. subset the original data frame according to the filter supplied (Believe==FALSE); then

  2. get the row count of this subset

For the first step, the subset function is a good way to do this (just an alternative to ordinary index or bracket notation).

For the second step, i would use dim or nrow

One advantage of using subset: you don't have to parse the result it returns to get the result you need--just call nrow on it directly.

so in your case:

v = nrow(subset(Santa, Believe==FALSE))     # 'subset' returns a data.frame

or wrapped in an anonymous function:

>> fnx = function(fac, lev){nrow(subset(Santa, fac==lev))}

>> fnx(Believe, TRUE)
      3

Aside from nrow, dim will also do the job. This function returns the dimensions of a data frame (rows, cols) so you just need to supply the appropriate index to access the number of rows:

v = dim(subset(Santa, Believe==FALSE))[1] 

An answer to the OP posted before this one shows the use of a contingency table. I don't like that approach for the general problem as recited in the OP. Here's the reason. Granted, the general problem of how many rows in this data frame have value x in column C? can be answered using a contingency table as well as using a "filtering" scheme (as in my answer here). If you want row counts for all values for a given factor variable (column) then a contingency table (via calling table and passing in the column(s) of interest) is the most sensible solution; however, the OP asks for the count of a particular value in a factor variable, not counts across all values. Aside from the performance hit (might be big, might be trivial, just depends on the size of the data frame and the processing pipeline context in which this function resides). And of course once the result from the call to table is returned, you still have to parse from that result just the count that you want.

So that's why, to me, this is a filtering rather than a cross-tab problem.

Breaking up long strings on multiple lines in Ruby without stripping newlines

You can use \ to indicate that any line of Ruby continues on the next line. This works with strings too:

string = "this is a \
string that spans lines"

puts string.inspect

will output "this is a string that spans lines"

Email address validation using ASP.NET MVC data type attributes

You need to use RegularExpression Attribute, something like this:

[RegularExpression("^[a-zA-Z0-9_\\.-]+@([a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,6}$", ErrorMessage = "E-mail is not valid")]

And don't delete [Required] because [RegularExpression] doesn't affect empty fields.

Why does ANT tell me that JAVA_HOME is wrong when it is not?

I was facing the same problem, making the executable property in the javac tag to be set to the location of javac.exe resolved the problem for me. This resolved the problem

<javac srcdir="${srcDir}" destdir="${buildDir}" fork="true" executable="C:\Program Files\Java\jdk1.7.0_03\bin\javac"/>

Why does an SSH remote command get fewer environment variables then when run manually?

There are different types of shells. The SSH command execution shell is a non-interactive shell, whereas your normal shell is either a login shell or an interactive shell. Description follows, from man bash:

       A  login  shell  is  one whose first character of argument
       zero is a -, or one started with the --login option.

       An interactive shell is  one  started  without  non-option
       arguments  and  without the -c option whose standard input
       and error are both connected to terminals  (as  determined
       by  isatty(3)), or one started with the -i option.  PS1 is
       set and $- includes i if bash is interactive,  allowing  a
       shell script or a startup file to test this state.

       The  following  paragraphs  describe how bash executes its
       startup files.  If any of the files exist  but  cannot  be
       read,  bash reports an error.  Tildes are expanded in file
       names as described below  under  Tilde  Expansion  in  the
       EXPANSION section.

       When  bash is invoked as an interactive login shell, or as
       a non-interactive shell with the --login option, it  first
       reads and executes commands from the file /etc/profile, if
       that file exists.  After reading that file, it  looks  for
       ~/.bash_profile,  ~/.bash_login,  and  ~/.profile, in that
       order, and reads and executes commands from the first  one
       that  exists  and is readable.  The --noprofile option may
       be used when the shell is started to inhibit  this  behavĀ­
       ior.

       When a login shell exits, bash reads and executes commands
       from the file ~/.bash_logout, if it exists.

       When an interactive shell that is not  a  login  shell  is
       started,  bash reads and executes commands from ~/.bashrc,
       if that file exists.  This may be inhibited by  using  the
       --norc  option.   The --rcfile file option will force bash
       to  read  and  execute  commands  from  file  instead   of
       ~/.bashrc.

       When  bash  is  started  non-interactively, to run a shell
       script, for example, it looks for the variable BASH_ENV in
       the  environment,  expands  its value if it appears there,
       and uses the expanded value as the name of a file to  read
       and  execute.   Bash  behaves  as if the following command
       were executed:
              if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
       but the value of the PATH variable is not used  to  search
       for the file name.

Simple Random Samples from a Sql database

Maybe you could do

SELECT * FROM table LIMIT 10000 OFFSET FLOOR(RAND() * 190000)

Java String declaration

String str = new String("SOME")

always create a new object on the heap

String str="SOME" 

uses the String pool

Try this small example:

        String s1 = new String("hello");
        String s2 = "hello";
        String s3 = "hello";

        System.err.println(s1 == s2);
        System.err.println(s2 == s3);

To avoid creating unnecesary objects on the heap use the second form.

How to change environment's font size?

  1. Open VS Code
  2. Type command CTRL + SHFT + P
  3. Type Settings
  4. Settings file will open.
  5. Now under User > Text Editor > Font, find Font Size
  6. Enter your desired font size

That's it.

How do I view Android application specific cache?

On Android Studio you can use Device File Explorer to view /data/data/my_app_package/cache.

Click View > Tool Windows > Device File Explorer or click the Device File Explorer button in the tool window bar to open the Device File Explorer.

Documentation

Python Unicode Encode Error

Excellent post : http://www.carlosble.com/2010/12/understanding-python-and-unicode/

# -*- coding: utf-8 -*-

def __if_number_get_string(number):
    converted_str = number
    if isinstance(number, int) or \
            isinstance(number, float):
        converted_str = str(number)
    return converted_str


def get_unicode(strOrUnicode, encoding='utf-8'):
    strOrUnicode = __if_number_get_string(strOrUnicode)
    if isinstance(strOrUnicode, unicode):
        return strOrUnicode
    return unicode(strOrUnicode, encoding, errors='ignore')


def get_string(strOrUnicode, encoding='utf-8'):
    strOrUnicode = __if_number_get_string(strOrUnicode)
    if isinstance(strOrUnicode, unicode):
        return strOrUnicode.encode(encoding)
    return strOrUnicode

Is it possible to decrypt SHA1

Since SHA-1 maps several byte sequences to one, you can't "decrypt" a hash, but in theory you can find collisions: strings that have the same hash.

It seems that breaking a single hash would cost about 2.7 million dollars worth of computer time currently, so your efforts are probably better spent somewhere else.

How to bring a window to the front?

Hj, all methods of yours are not working for me, in Fedora KDE 14. I have a dirty way to do bring a window to front, while we're waiting for Oracle to fix this issue.

import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.Robot;
import java.awt.event.InputEvent;

public class FrameMain extends javax.swing.JFrame {

  //...
  private final javax.swing.JFrame mainFrame = this;

  private void toggleVisible() {
    setVisible(!isVisible());
    if (isVisible()) {
      toFront();
      requestFocus();
      setAlwaysOnTop(true);
      try {
        //remember the last location of mouse
        final Point oldMouseLocation = MouseInfo.getPointerInfo().getLocation();

        //simulate a mouse click on title bar of window
        Robot robot = new Robot();
        robot.mouseMove(mainFrame.getX() + 100, mainFrame.getY() + 5);
        robot.mousePress(InputEvent.BUTTON1_DOWN_MASK);
        robot.mouseRelease(InputEvent.BUTTON1_DOWN_MASK);

        //move mouse to old location
        robot.mouseMove((int) oldMouseLocation.getX(), (int) oldMouseLocation.getY());
      } catch (Exception ex) {
        //just ignore exception, or you can handle it as you want
      } finally {
        setAlwaysOnTop(false);
      }
    }
  }

  //...

}

And, this works perfectly in my Fedora KDE 14 :-)

SVN Error - Not a working copy

Maybe you just copied tree of folder and trying to add lowest one.

SVN
|_
  |
  subfolder1
       |
       subfolder2   (here you get an error)

in that case you have to commit directory on the upper level.

getResourceAsStream() vs FileInputStream

getResourceAsStream is the right way to do it for web apps (as you already learned).

The reason is that reading from the file system cannot work if you package your web app in a WAR. This is the proper way to package a web app. It's portable that way, because you aren't dependent on an absolute file path or the location where your app server is installed.

JAXB: How to ignore namespace during unmarshalling XML document?

I believe you must add the namespace to your xml document, with, for example, the use of a SAX filter.

That means:

  • Define a ContentHandler interface with a new class which will intercept SAX events before JAXB can get them.
  • Define a XMLReader which will set the content handler

then link the two together:

public static Object unmarshallWithFilter(Unmarshaller unmarshaller,
java.io.File source) throws FileNotFoundException, JAXBException 
{
    FileReader fr = null;
    try {
        fr = new FileReader(source);
        XMLReader reader = new NamespaceFilterXMLReader();
        InputSource is = new InputSource(fr);
        SAXSource ss = new SAXSource(reader, is);
        return unmarshaller.unmarshal(ss);
    } catch (SAXException e) {
        //not technically a jaxb exception, but close enough
        throw new JAXBException(e);
    } catch (ParserConfigurationException e) {
        //not technically a jaxb exception, but close enough
        throw new JAXBException(e);
    } finally {
        FileUtil.close(fr); //replace with this some safe close method you have
    }
}

LINQ query to return a Dictionary<string, string>

Look at the ToLookup and/or ToDictionary extension methods.

Should I learn C before learning C++?

I'm going to disagree with the majority here. I think you should learn C before learning C++. It's definitely not necessary, but I think it makes learning C++ a lot easier. C is at the heart of C++. Anything you learn about C is applicable to C++, but C is a lot smaller and easier to learn.

Pick up K&R and read through that. It is short and will give you a sufficient sense of the language. Once you have the basics of pointers and function calls down, you can move on to C++ a little easier.

SQLRecoverableException: I/O Exception: Connection reset

Solution
Change the setup for your application, so you this parameter[-Djava.security.egd=file:/dev/../dev/urandom] next to the java command:

java -Djava.security.egd=file:/dev/../dev/urandom [your command]

Ref :- https://community.oracle.com/thread/943911

How can I import data into mysql database via mysql workbench?

For MySQL Workbench 8.0 navigate to:

Server > Data Import

A new tab called Administration - Data Import/Restore appears. There you can choose to import a Dump Project Folder or use a specific SQL file according to your needs. Then you must select a schema where the data will be imported to, or you have to click the New... button to type a name for the new schema.

Then you can select the database objects to be imported or just click the Start Import button in the lower right part of the tab area.

Having done that and if the import was successful, you'll need to update the Schema Navigator by clicking the arrow circle icon.

That's it!

For more detailed info, check the MySQL Workbench Manual: 6.5.2 SQL Data Export and Import Wizard

How to convert current date to epoch timestamp?

enter image description hereI think this answer needs an update and the solution would go better this way.

from datetime import datetime

datetime.strptime("29.08.2011 11:05:02", "%d.%m.%Y %H:%M:%S").strftime("%s")

or you may use datetime object and format the time using %s to convert it into epoch time.

How to compile python script to binary executable

Since other SO answers link to this question it's worth noting that there is another option now in PyOxidizer.

It's a rust utility which works in some of the same ways as pyinstaller, however has some additional features detailed here, to summarize the key ones:

  • Single binary of all packages by default with the ability to do a zero-copy load of modules into memory, vs pyinstaller extracting them to a temporary directory when using onefile mode
  • Ability to produce a static linked binary

(One other advantage of pyoxidizer is that it does not seem to suffer from the GLIBC_X.XX not found problem that can crop up with pyinstaller if you've created your binary on a system that has a glibc version newer than the target system).

Overall pyinstaller is much simpler to use than PyOxidizer, which often requires some complexity in the configuration file, and it's less Pythony since it's written in Rust and uses a configuration file format not very familiar in the Python world, but PyOxidizer does some more advanced stuff, especially if you are looking to produce single binaries (which is not pyinstaller's default).

ArrayAdapter in android to create simple listview

But again main doubt why TextView resource id it needs?

Look at the constructor and the params.

public ArrayAdapter (Context context, int resource, int textViewResourceId, T[] objects)

Added in API level 1 Constructor

Parameters

context The current context.

resource The resource ID for a layout file containing a layout to use when instantiating views.

textViewResourceId The id of the TextView within the layout resource to be populated objects The objects to represent in the ListView.

android.R.id.text1 refers to the id of text in android resource. So you need not have the one in your activity.

Here's the full list

http://developer.android.com/reference/android/R.id.html

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
        android.R.layout.simple_list_item_1, android.R.id.text1, values);

this refers to activity context

android.R.layout.simple_list_item_1 simple_list_item_1 is the layout in android.R.layout.

android.R.id.text1 refers to the android resource id.

values is a string array from the link you provided

http://developer.android.com/reference/android/R.layout.html

Bash array with spaces in elements

I used to reset the IFS value and rollback when done.

# backup IFS value
O_IFS=$IFS

# reset IFS value
IFS=""

FILES=(
"2011-09-04 21.43.02.jpg"
"2011-09-05 10.23.14.jpg"
"2011-09-09 12.31.16.jpg"
"2011-09-11 08.43.12.jpg"
)

for file in ${FILES[@]}; do
    echo ${file}
done

# rollback IFS value
IFS=${O_IFS}

Possible output from the loop:

2011-09-04 21.43.02.jpg

2011-09-05 10.23.14.jpg

2011-09-09 12.31.16.jpg

2011-09-11 08.43.12.jpg

Slide right to left Android Animations

<translate
    android:fromXDelta="100%p"
    android:toXDelta="0%p"
    android:duration="500" />

invalid use of non-static member function

The simplest fix is to make the comparator function be static:

static int comparator (const Bar & first, const Bar & second);
^^^^^^

When invoking it in Count, its name will be Foo::comparator.

The way you have it now, it does not make sense to be a non-static member function because it does not use any member variables of Foo.

Another option is to make it a non-member function, especially if it makes sense that this comparator might be used by other code besides just Foo.

If WorkSheet("wsName") Exists

Slightly changed to David Murdoch's code for generic library

Function HasByName(cSheetName As String, _ 
                   Optional oWorkBook As Excel.Workbook) As Boolean

    HasByName = False
    Dim wb

    If oWorkBook Is Nothing Then
        Set oWorkBook = ThisWorkbook
    End If

    For Each wb In oWorkBook.Worksheets
        If wb.Name = cSheetName Then
            HasByName = True
            Exit Function
        End If
    Next wb
End Function

How to set the java.library.path from Eclipse

Just add the *.dll files to your c:/windows

You can get the java.library.path from the follow codes:and then add you dll files under any path of you get

import java.util.logging.Logger;

public class Test {


    static Logger logger = Logger.getLogger(Test.class.getName());
    public static void main(String[] args) {
    logger.info(System.getProperty("java.library.path"));
    }
}

Getting value from table cell in JavaScript...not jQuery

If I understand your question correctly, you are looking for innerHTML:

alert(col.firstChild.innerHTML);

Regex matching in a Bash if statement

There are a couple of important things to know about bash's [[ ]] construction. The first:

Word splitting and pathname expansion are not performed on the words between the [[ and ]]; tilde expansion, parameter and variable expansion, arithmetic expansion, command substitution, process substitution, and quote removal are performed.

The second thing:

An additional binary operator, ā€˜=~ā€™, is available,... the string to the right of the operator is considered an extended regular expression and matched accordingly... Any part of the pattern may be quoted to force it to be matched as a string.

Consequently, $v on either side of the =~ will be expanded to the value of that variable, but the result will not be word-split or pathname-expanded. In other words, it's perfectly safe to leave variable expansions unquoted on the left-hand side, but you need to know that variable expansions will happen on the right-hand side.

So if you write: [[ $x =~ [$0-9a-zA-Z] ]], the $0 inside the regex on the right will be expanded before the regex is interpreted, which will probably cause the regex to fail to compile (unless the expansion of $0 ends with a digit or punctuation symbol whose ascii value is less than a digit). If you quote the right-hand side like-so [[ $x =~ "[$0-9a-zA-Z]" ]], then the right-hand side will be treated as an ordinary string, not a regex (and $0 will still be expanded). What you really want in this case is [[ $x =~ [\$0-9a-zA-Z] ]]

Similarly, the expression between the [[ and ]] is split into words before the regex is interpreted. So spaces in the regex need to be escaped or quoted. If you wanted to match letters, digits or spaces you could use: [[ $x =~ [0-9a-zA-Z\ ] ]]. Other characters similarly need to be escaped, like #, which would start a comment if not quoted. Of course, you can put the pattern into a variable:

pat="[0-9a-zA-Z ]"
if [[ $x =~ $pat ]]; then ...

For regexes which contain lots of characters which would need to be escaped or quoted to pass through bash's lexer, many people prefer this style. But beware: In this case, you cannot quote the variable expansion:

# This doesn't work:
if [[ $x =~ "$pat" ]]; then ...

Finally, I think what you are trying to do is to verify that the variable only contains valid characters. The easiest way to do this check is to make sure that it does not contain an invalid character. In other words, an expression like this:

valid='0-9a-zA-Z $%&#' # add almost whatever else you want to allow to the list
if [[ ! $x =~ [^$valid] ]]; then ...

! negates the test, turning it into a "does not match" operator, and a [^...] regex character class means "any character other than ...".

The combination of parameter expansion and regex operators can make bash regular expression syntax "almost readable", but there are still some gotchas. (Aren't there always?) One is that you could not put ] into $valid, even if $valid were quoted, except at the very beginning. (That's a Posix regex rule: if you want to include ] in a character class, it needs to go at the beginning. - can go at the beginning or the end, so if you need both ] and -, you need to start with ] and end with -, leading to the regex "I know what I'm doing" emoticon: [][-])

How can I find out the total physical memory (RAM) of my linux box suitable to be parsed by a shell script?

One more useful command:
vmstat -s | grep memory
sample output on my machine is:

  2050060 K total memory
  1092992 K used memory
   743072 K active memory
   177084 K inactive memory
   957068 K free memory
   385388 K buffer memory

another useful command to get memory information is:
free
sample output is:

             total       used       free     shared    buffers     cached
Mem:       2050060    1093324     956736        108     385392     386812
-/+ buffers/cache:     321120    1728940
Swap:      2095100       2732    2092368

One observation here is that, the command free gives information about swap space also.
The following link may be useful for you:
http://www.linuxnix.com/find-ram-details-in-linuxunix/

Python script to convert from UTF-8 to ASCII

import codecs

 ...

fichier = codecs.open(filePath, "r", encoding="utf-8")

 ...

fichierTemp = codecs.open("tempASCII", "w", encoding="ascii", errors="ignore")
fichierTemp.write(contentOfFile)

 ...

.NET data structures: ArrayList, List, HashTable, Dictionary, SortedList, SortedDictionary -- Speed, memory, and when to use each?

There are subtle and not-so-subtle differences between generic and non-generic collections. They merely use different underlying data structures. For example, Hashtable guarantees one-writer-many-readers without sync. Dictionary does not.

Removing specific rows from a dataframe

One simple solution:

cond1 <- df$sub == 1 & df$day == 2

cond2 <- df$sub == 3 & df$day == 4

df <- df[!(cond1 | cond2),]

Error: Could not find or load main class in intelliJ IDE

I'm using IntelliJ with Spring and my main class is wrapped in a JAR. I had to mark the 'Include dependencies with "Provided" scope' in the Run/Debug configuration dialog

How to make a JFrame Modal in Swing java

As others mentioned, you could use JDialog. If you don't have access to the parent frame or you want to freeze the hole application just pass null as a parent:

final JDialog frame = new JDialog((JFrame)null, frameTitle, true); frame.setModal(true);
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);

Force IE9 to emulate IE8. Possible?

You can use the document compatibility mode to do this, which is what you were trying.. However, thing to note is: It must appear in the Web page's header (the HEAD section) before all other elements, except for the title element and other meta elements Hope that was the issue.. Also, The X-UA-compatible header is not case sensitive Refer: http://msdn.microsoft.com/en-us/library/cc288325%28v=vs.85%29.aspx#SetMode

Edit: in case something happens to kill the msdn link, here is the content:

Specifying Document Compatibility Modes

You can use document modes to control the way Internet Explorer interprets and displays your webpage. To specify a specific document mode for your webpage, use the meta element to include an X-UA-Compatible header in your webpage, as shown in the following example.

<html>
<head>
  <!-- Enable IE9 Standards mode -->
  <meta http-equiv="X-UA-Compatible" content="IE=9" >
  <title>My webpage</title>
</head>
<body>
  <p>Content goes here.</p>
</body>
</html> 

If you view this webpage in Internet Explorer 9, it will be displayed in IE9 mode.

The following example specifies EmulateIE7 mode.

<html>
<head>
  <!-- Mimic Internet Explorer 7 -->
  <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" >
  <title>My webpage</title>
</head>
<body>
  <p>Content goes here.</p>
</body>
</html> 

In this example, the X-UA-Compatible header directs Internet Explorer to mimic the behavior of Internet Explorer 7 when determining how to display the webpage. This means that Internet Explorer will use the directive (or lack thereof) to choose the appropriate document type. Because this page does not contain a directive, the example would be displayed in IE5 (Quirks) mode.

How to read user input into a variable in Bash?

Try this

#/bin/bash

read -p "Enter a word: " word
echo "You entered $word"

Linux c++ error: undefined reference to 'dlopen'

The topic is quite old, yet I struggled with the same issue today while compiling cegui 0.7.1 (openVibe prerequisite).

What worked for me was to set: LDFLAGS="-Wl,--no-as-needed" in the Makefile.

I've also tried -ldl for LDFLAGS but to no avail.

How to delete a selected DataGridViewRow and update a connected database table?

Well, this is how I usually delete checked rows by the user from a DataGridView, if you are associating it with a DataTable from a Dataset (ex: DataGridView1.DataSource = Dataset1.Tables["x"]), then once you will make any updates (delete, insert,update) in the Dataset, it will automatically happen in your DataGridView.

if (MessageBox.Show("Are you sure you want to delete this record(s)", "confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Information) == System.Windows.Forms.DialogResult.Yes)
        {
            try
            {
                for (int i = dgv_Championnat.RowCount -1; i > -1; i--)
                {
                    if (Convert.ToBoolean(dgv_Championnat.Rows[i].Cells[0].Value) == true)
                    {
                        Program.set.Tables["Champ"].Rows[i].Delete();
                    }
                }
                Program.command = new SqlCommandBuilder(Program.AdapterChampionnat);
                if (Program.AdapterChampionnat.Update(Program.TableChampionnat) > 0)
                {
                    MessageBox.Show("Well Deleted");
                }
            }
            catch (SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

How do I disable a Button in Flutter?

I like to use flutter_mobx for this and work on the state.

Next I use an observer:

Container(child: Observer(builder: (_) {
  var method;
  if (!controller.isDisabledButton) method = controller.methodController;
  return RaiseButton(child: Text('Test') onPressed: method);
}));

On the Controller:

@observable
bool isDisabledButton = true;

Then inside the control you can manipulate this variable as you want.

Refs.: Flutter mobx

How to load local file in sc.textFile, instead of HDFS

You need just to specify the path of the file as "file:///directory/file"

example:

val textFile = sc.textFile("file:///usr/local/spark/README.md")

WCF service startup error "This collection already contains an address with scheme http"

Summary,

Code solution: Here

Configuration solutions: Here

With the help of Mike Chaliy, I found some solutions on how to do this through code. Because this issue is going to affect pretty much all projects we deploy to a live environment I held out for a purely configuration solution. I eventually found one which details how to do it in .net 3.0 and .net 3.5.

Taken from the site, below is an example of how to alter your applications web config:

<system.serviceModel>
    <serviceHostingEnvironment>
        <baseAddressPrefixFilters>
            <add prefix="net.tcp://payroll.myorg.com:8000"/>
            <add prefix="http://shipping.myorg.com:9000"/>
        </baseAddressPrefixFilters>
    </serviceHostingEnvironment>
</system.serviceModel>

In the above example, net.tcp://payroll.myorg.com:8000 and http://shipping.myorg.com:9000 are the only base addresses, for their respective schemes, which will be allowed to be passed through. The baseAddressPrefixFilter does not support any wildcards .

The baseAddresses supplied by IIS may have addresses bound to other schemes not present in baseAddressPrefixFilter list. These addresses will not be filtered out.

Dns solution (untested): I think that if you created a new dns entry specific to your web application, added a new web site, and gave it a single host header matching the dns entry, you would mitigate this issue altogether, and would not have to write custom code or add prefixes to your web.config file.

How do I delete all the duplicate records in a MySQL table without temp tables

Add Unique Index on your table:

ALTER IGNORE TABLE `TableA`   
ADD UNIQUE INDEX (`member_id`, `quiz_num`, `question_num`, `answer_num`);

Another way to do this would be:

Add primary key in your table then you can easily remove duplicates from your table using the following query:

DELETE FROM member  
WHERE id IN (SELECT * 
             FROM (SELECT id FROM member 
                   GROUP BY member_id, quiz_num, question_num, answer_num HAVING (COUNT(*) > 1)
                  ) AS A
            );

Populating a data frame in R in a loop

I had a case in where I was needing to use a data frame within a for loop function. In this case, it was the "efficient", however, keep in mind that the database was small and the iterations in the loop were very simple. But maybe the code could be useful for some one with similar conditions.

The for loop purpose was to use the raster extract function along five locations (i.e. 5 Tokio, New York, Sau Paulo, Seul & Mexico city) and each location had their respective raster grids. I had a spatial point database with more than 1000 observations allocated within the 5 different locations and I was needing to extract information from 10 different raster grids (two grids per location). Also, for the subsequent analysis, I was not only needing the raster values but also the unique ID for each observations.

After preparing the spatial data, which included the following tasks:

  1. Import points shapefile with the readOGR function (rgdap package)
  2. Import raster files with the raster function (raster package)
  3. Stack grids from the same location into one file, with the function stack (raster package)

Here the for loop code with the use of a data frame:

1. Add stacked rasters per location into a list

raslist <- list(LOC1,LOC2,LOC3,LOC4,LOC5)

2. Create an empty dataframe, this will be the output file

TB <- data.frame(VAR1=double(),VAR2=double(),ID=character())

3. Set up for loop function

L1 <- seq(1,5,1) # the location ID is a numeric variable with values from 1 to 5 

for (i in 1:length(L1)) {
  dat=subset(points,LOCATION==i) # select corresponding points for location [i] 
  t=data.frame(extract(raslist[[i]],dat),dat$ID) # run extract function with points & raster stack for location [i]
  names(t)=c("VAR1","VAR2","ID") 
  TB=rbind(TB,t)
}

How does the "view" method work in PyTorch?

Let's do some examples, from simpler to more difficult.

  1. The view method returns a tensor with the same data as the self tensor (which means that the returned tensor has the same number of elements), but with a different shape. For example:

    a = torch.arange(1, 17)  # a's shape is (16,)
    
    a.view(4, 4) # output below
      1   2   3   4
      5   6   7   8
      9  10  11  12
     13  14  15  16
    [torch.FloatTensor of size 4x4]
    
    a.view(2, 2, 4) # output below
    (0 ,.,.) = 
    1   2   3   4
    5   6   7   8
    
    (1 ,.,.) = 
     9  10  11  12
    13  14  15  16
    [torch.FloatTensor of size 2x2x4]
    
  2. Assuming that -1 is not one of the parameters, when you multiply them together, the result must be equal to the number of elements in the tensor. If you do: a.view(3, 3), it will raise a RuntimeError because shape (3 x 3) is invalid for input with 16 elements. In other words: 3 x 3 does not equal 16 but 9.

  3. You can use -1 as one of the parameters that you pass to the function, but only once. All that happens is that the method will do the math for you on how to fill that dimension. For example a.view(2, -1, 4) is equivalent to a.view(2, 2, 4). [16 / (2 x 4) = 2]

  4. Notice that the returned tensor shares the same data. If you make a change in the "view" you are changing the original tensor's data:

    b = a.view(4, 4)
    b[0, 2] = 2
    a[2] == 3.0
    False
    
  5. Now, for a more complex use case. The documentation says that each new view dimension must either be a subspace of an original dimension, or only span d, d + 1, ..., d + k that satisfy the following contiguity-like condition that for all i = 0, ..., k - 1, stride[i] = stride[i + 1] x size[i + 1]. Otherwise, contiguous() needs to be called before the tensor can be viewed. For example:

    a = torch.rand(5, 4, 3, 2) # size (5, 4, 3, 2)
    a_t = a.permute(0, 2, 3, 1) # size (5, 3, 2, 4)
    
    # The commented line below will raise a RuntimeError, because one dimension
    # spans across two contiguous subspaces
    # a_t.view(-1, 4)
    
    # instead do:
    a_t.contiguous().view(-1, 4)
    
    # To see why the first one does not work and the second does,
    # compare a.stride() and a_t.stride()
    a.stride() # (24, 6, 2, 1)
    a_t.stride() # (24, 2, 1, 6)
    

    Notice that for a_t, stride[0] != stride[1] x size[1] since 24 != 2 x 3

Cosine Similarity between 2 Number Lists

import math
from itertools import izip

def dot_product(v1, v2):
    return sum(map(lambda x: x[0] * x[1], izip(v1, v2)))

def cosine_measure(v1, v2):
    prod = dot_product(v1, v2)
    len1 = math.sqrt(dot_product(v1, v1))
    len2 = math.sqrt(dot_product(v2, v2))
    return prod / (len1 * len2)

You can round it after computing:

cosine = format(round(cosine_measure(v1, v2), 3))

If you want it really short, you can use this one-liner:

from math import sqrt
from itertools import izip

def cosine_measure(v1, v2):
    return (lambda (x, y, z): x / sqrt(y * z))(reduce(lambda x, y: (x[0] + y[0] * y[1], x[1] + y[0]**2, x[2] + y[1]**2), izip(v1, v2), (0, 0, 0)))

Correct way to find max in an Array in Swift

Given:

let numbers = [1, 2, 3, 4, 5]

Swift 3:

numbers.min() // equals 1
numbers.max() // equals 5

Swift 2:

numbers.minElement() // equals 1
numbers.maxElement() // equals 5

How can I trigger a JavaScript event click

Use a testing framework

This might be helpful - http://seleniumhq.org/ - Selenium is a web application automated testing system.

You can create tests using the Firefox plugin Selenium IDE

Manual firing of events

To manually fire events the correct way you will need to use different methods for different browsers - either el.dispatchEvent or el.fireEvent where el will be your Anchor element. I believe both of these will require constructing an Event object to pass in.

The alternative, not entirely correct, quick-and-dirty way would be this:

var el = document.getElementById('anchorelementid');
el.onclick(); // Not entirely correct because your event handler will be called
              // without an Event object parameter.

Select every Nth element in CSS

You need the correct argument for the nth-child pseudo class.

  • The argument should be in the form of an + b to match every ath child starting from b.

  • Both a and b are optional integers and both can be zero or negative.

    • If a is zero then there is no "every ath child" clause.
    • If a is negative then matching is done backwards starting from b.
    • If b is zero or negative then it is possible to write equivalent expression using positive b e.g. 4n+0 is same as 4n+4. Likewise 4n-1 is same as 4n+3.

Examples:

Select every 4th child (4, 8, 12, ...)

_x000D_
_x000D_
li:nth-child(4n) {_x000D_
  background: yellow;_x000D_
}
_x000D_
<ol>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
</ol>
_x000D_
_x000D_
_x000D_

Select every 4th child starting from 1 (1, 5, 9, ...)

_x000D_
_x000D_
li:nth-child(4n+1) {_x000D_
  background: yellow;_x000D_
}
_x000D_
<ol>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
</ol>
_x000D_
_x000D_
_x000D_

Select every 3rd and 4th child from groups of 4 (3 and 4, 7 and 8, 11 and 12, ...)

_x000D_
_x000D_
/* two selectors are required */_x000D_
li:nth-child(4n+3),_x000D_
li:nth-child(4n+4) {_x000D_
  background: yellow;_x000D_
}
_x000D_
<ol>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
</ol>
_x000D_
_x000D_
_x000D_

Select first 4 items (4, 3, 2, 1)

_x000D_
_x000D_
/* when a is negative then matching is done backwards  */_x000D_
li:nth-child(-n+4) {_x000D_
  background: yellow;_x000D_
}
_x000D_
<ol>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
  <li>Item</li>_x000D_
</ol>
_x000D_
_x000D_
_x000D_

How to serve all existing static files directly with NGINX, but proxy the rest to a backend server.

Try this:

location / {
    root /path/to/root;
    expires 30d;
    access_log off;
}

location ~* ^.*\.php$ {
    if (!-f $request_filename) {
        return 404;
    }
    proxy_set_header X-Real-IP  $remote_addr;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass http://127.0.0.1:8080;
}

Hopefully it works. Regular expressions have higher priority than plain strings, so all requests ending in .php should be forwared to Apache if only a corresponding .php file exists. Rest will be handled as static files. The actual algorithm of evaluating location is here.

How to resize an image to a specific size in OpenCV?

Make a useful function like this:

IplImage* img_resize(IplImage* src_img, int new_width,int new_height)
{
    IplImage* des_img;
    des_img=cvCreateImage(cvSize(new_width,new_height),src_img->depth,src_img->nChannels);
    cvResize(src_img,des_img,CV_INTER_LINEAR);
    return des_img;
} 

TypeError: 'dict_keys' object does not support indexing

You're passing the result of somedict.keys() to the function. In Python 3, dict.keys doesn't return a list, but a set-like object that represents a view of the dictionary's keys and (being set-like) doesn't support indexing.

To fix the problem, use list(somedict.keys()) to collect the keys, and work with that.

how to convert a string to an array in php

explode ā€” Split a string by a string

Syntax :

array explode ( string $delimiter , string $string [, int $limit = PHP_INT_MAX ] )
  • $delimiter : based on which you want to split string
  • $string. : The string you want to split

Example :

// Example 1
$pizza  = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo $pieces[0]; // piece1
echo $pieces[1]; // piece2

In your example :

$str = "this is string"; 
$array = explode(' ', $str);

How to get progress from XMLHttpRequest

For the bytes uploaded it is quite easy. Just monitor the xhr.upload.onprogress event. The browser knows the size of the files it has to upload and the size of the uploaded data, so it can provide the progress info.

For the bytes downloaded (when getting the info with xhr.responseText), it is a little bit more difficult, because the browser doesn't know how many bytes will be sent in the server request. The only thing that the browser knows in this case is the size of the bytes it is receiving.

There is a solution for this, it's sufficient to set a Content-Length header on the server script, in order to get the total size of the bytes the browser is going to receive.

For more go to https://developer.mozilla.org/en/Using_XMLHttpRequest .

Example: My server script reads a zip file (it takes 5 seconds):

$filesize=filesize('test.zip');

header("Content-Length: " . $filesize); // set header length
// if the headers is not set then the evt.loaded will be 0
readfile('test.zip');
exit 0;

Now I can monitor the download process of the server script, because I know it's total length:

function updateProgress(evt) 
{
   if (evt.lengthComputable) 
   {  // evt.loaded the bytes the browser received
      // evt.total the total bytes set by the header
      // jQuery UI progress bar to show the progress on screen
     var percentComplete = (evt.loaded / evt.total) * 100;  
     $('#progressbar').progressbar( "option", "value", percentComplete );
   } 
}   
function sendreq(evt) 
{  
    var req = new XMLHttpRequest(); 
    $('#progressbar').progressbar();    
    req.onprogress = updateProgress;
    req.open('GET', 'test.php', true);  
    req.onreadystatechange = function (aEvt) {  
        if (req.readyState == 4) 
        {  
             //run any callback here
        }  
    };  
    req.send(); 
}

How can I use break or continue within for loop in Twig template?

A way to be able to use {% break %} or {% continue %} is to write TokenParsers for them.

I did it for the {% break %} token in the code below. You can, without much modifications, do the same thing for the {% continue %}.

  • AppBundle\Twig\AppExtension.php:

    namespace AppBundle\Twig;
    
    class AppExtension extends \Twig_Extension
    {
        function getTokenParsers() {
            return array(
                new BreakToken(),
            );
        }
    
        public function getName()
        {
            return 'app_extension';
        }
    }
    
  • AppBundle\Twig\BreakToken.php:

    namespace AppBundle\Twig;
    
    class BreakToken extends \Twig_TokenParser
    {
        public function parse(\Twig_Token $token)
        {
            $stream = $this->parser->getStream();
            $stream->expect(\Twig_Token::BLOCK_END_TYPE);
    
            // Trick to check if we are currently in a loop.
            $currentForLoop = 0;
    
            for ($i = 1; true; $i++) {
                try {
                    // if we look before the beginning of the stream
                    // the stream will throw a \Twig_Error_Syntax
                    $token = $stream->look(-$i);
                } catch (\Twig_Error_Syntax $e) {
                    break;
                }
    
                if ($token->test(\Twig_Token::NAME_TYPE, 'for')) {
                    $currentForLoop++;
                } else if ($token->test(\Twig_Token::NAME_TYPE, 'endfor')) {
                    $currentForLoop--;
                }
            }
    
    
            if ($currentForLoop < 1) {
                throw new \Twig_Error_Syntax(
                    'Break tag is only allowed in \'for\' loops.',
                    $stream->getCurrent()->getLine(),
                    $stream->getSourceContext()->getName()
                );
            }
    
            return new BreakNode();
        }
    
        public function getTag()
        {
            return 'break';
        }
    }
    
  • AppBundle\Twig\BreakNode.php:

    namespace AppBundle\Twig;
    
    class BreakNode extends \Twig_Node
    {
        public function compile(\Twig_Compiler $compiler)
        {
            $compiler
                ->write("break;\n")
            ;
        }
    }
    

Then you can simply use {% break %} to get out of loops like this:

{% for post in posts %}
    {% if post.id == 10 %}
        {% break %}
    {% endif %}
    <h2>{{ post.heading }}</h2>
{% endfor %}

To go even further, you may write token parsers for {% continue X %} and {% break X %} (where X is an integer >= 1) to get out/continue multiple loops like in PHP.

How to convert date into this 'yyyy-MM-dd' format in angular 2

The same problem I faced in my project. Thanks to @Umar Rashed, but I am going to explain it in detail.

First, Provide Date Pipe from app.module:

providers: [DatePipe]

Import to your component and app.module:

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

Second, declare it under the constructor:

constructor(
    public datepipe: DatePipe
  ) {

Dates come from the server and parsed to console like this:

2000-09-19T00:00:00

I convert the date to how I need with this code; in TypeScript:

this.datepipe.transform(this.birthDate, 'dd/MM/yyyy')

Show from HTML template:

{{ user.birthDate }}

and it is seen like this:

19/09/2000

also seen on the web site like this: dates shown as it is filtered (click to see the screenshot)

react-router - pass props to handler component

You can pass props by passing them to <RouteHandler> (in v0.13.x) or the Route component itself in v1.0;

// v0.13.x
<RouteHandler/>
<RouteHandler someExtraProp={something}/>

// v1.0
{this.props.children}
{React.cloneElement(this.props.children, {someExtraProp: something })}

(from the upgrade guide at https://github.com/rackt/react-router/releases/tag/v1.0.0)

All child handlers will receive the same set of props - this may be useful or not depending on the circumstance.

Can one do a for each loop in java in reverse order?

This may be an option. Hope there is a better way to start from last element than to while loop to the end.

public static void main(String[] args) {        
    List<String> a = new ArrayList<String>();
    a.add("1");a.add("2");a.add("3");a.add("4");a.add("5");

    ListIterator<String> aIter=a.listIterator();        
    while(aIter.hasNext()) aIter.next();

    for (;aIter.hasPrevious();)
    {
        String aVal = aIter.previous();
        System.out.println(aVal);           
    }
}

Access-Control-Allow-Origin error sending a jQuery Post to Google API's

There is a little hack with php. And it works not only with Google, but with any website you don't control and can't add Access-Control-Allow-Origin *

We need to create PHP-file (ex. getContentFromUrl.php) on our webserver and make a little trick.

PHP

<?php

$ext_url = $_POST['ext_url'];

echo file_get_contents($ext_url);

?>

JS

$.ajax({
    method: 'POST',
    url: 'getContentFromUrl.php', // link to your PHP file
    data: {
        // url where our server will send request which can't be done by AJAX
        'ext_url': 'https://stackoverflow.com/questions/6114436/access-control-allow-origin-error-sending-a-jquery-post-to-google-apis'
    },
    success: function(data) {
        // we can find any data on external url, cause we've got all page
        var $h1 = $(data).find('h1').html();

        $('h1').val($h1);
    },
    error:function() {
        console.log('Error');
    }
});

How it works:

  1. Your browser with the help of JS will send request to your server
  2. Your server will send request to any other server and get reply from another server (any website)
  3. Your server will send this reply to your JS

And we can make events onClick, put this event on some button. Hope this will help!

File Explorer in Android Studio

You can start Android Device Monitor from the Android Studio (green robot icon on the toolbar, to the left of the help icon). From the ADM, select the device/emulator, then select the File Explorer tab.

What is Bootstrap?

Bootstrap is an open-source CSS, JavaScript framework that was originally developed for twitter application by twitter's team of designers and developers. Then they released it for open-source. Being a longtime user of twitter bootstrap I find that its one of the best for designing mobile ready responsive websites. Many CSS and Javascript plugins are available for designing your website in no time. It's kind of rapid template design framework. Some people complain that the bootstrap CSS files are heavy and take time to load but these claims are made by lazy people. You don't have to keep the complete bootstrap.css in your website. You always have the option to remove the styles for components that you do not need for your website. For example, if you are only using basic components like forms and buttons then you can remove other components like accordions etc from the main CSS file. To start dabbling in bootstrap you can download the basic templates and components from getbootstrap site and let the magic happen.

NoClassDefFoundError - Eclipse and Android

This happens quite very often to me.

Last time that happened I can remembered was caused by switching the Eclipse ADT (Google special edition) to Android Studio, and switching back. I basically tried all methods that I can found on stackoverflow which didn't work for me.

Eventually, I got the app working again (no more NoCalssDeffoundError) by switching my IDE to original Eclipse (Kepler) with ADT.

Guzzlehttp - How get the body of a response from Guzzle 6?

If expecting JSON back, the simplest way to get it:

$data = json_decode($response->getBody()); // returns an object

// OR

$data = json_decode($response->getBody(), true); // returns an array

json_decode() will automatically cast the body to string, so there is no need to call getContents().

Include in SELECT a column that isn't actually in the database

You may want to use:

SELECT Name, 'Unpaid' AS Status FROM table;

The SELECT clause syntax, as defined in MSDN: SELECT Clause (Transact-SQL), is as follows:

SELECT [ ALL | DISTINCT ]
[ TOP ( expression ) [ PERCENT ] [ WITH TIES ] ] 
<select_list> 

Where the expression can be a constant, function, any combination of column names, constants, and functions connected by an operator or operators, or a subquery.

Java: Check if command line arguments are null

@jjnguy's answer is correct in most circumstances. You won't ever see a null String in the argument array (or a null array) if main is called by running the application is run from the command line in the normal way.

However, if some other part of the application calls a main method, it is conceivable that it might pass a null argument or null argument array.

However(2), this is clearly a highly unusual use-case, and it is an egregious violation of the implied contract for a main entry-point method. Therefore, I don't think you should bother checking for null argument values in main. In the unlikely event that they do occur, it is acceptable for the calling code to get a NullPointerException. After all, it is a bug in the caller to violate the contract.

Remove/ truncate leading zeros by javascript/jquery

parseInt(value) or parseFloat(value)

This will work nicely.

import android packages cannot be resolved

I just had the same problem after accepting a Java update--scores of build errors and android import not recognized. On checking the build path in Project=>Properties, I found that the check box for Android 4.3 had somehow gotten cleared. Checking it resolved all the import errors without my even having to restart the IDE or run a project clean.

How to download and save a file from Internet using Java?

Personally, I've found Apache's HttpClient to be more than capable of everything I've needed to do with regards to this. Here is a great tutorial on using HttpClient

Trim whitespace from a String

In addition to answer of @gjha:

inline std::string ltrim_copy(const std::string& str)
{
    auto it = std::find_if(str.cbegin(), str.cend(),
        [](char ch) { return !std::isspace<char>(ch, std::locale::classic()); });
    return std::string(it, str.cend());
}

inline std::string rtrim_copy(const std::string& str)
{
    auto it = std::find_if(str.crbegin(), str.crend(),
        [](char ch) { return !std::isspace<char>(ch, std::locale::classic()); });
    return it == str.crend() ? std::string() : std::string(str.cbegin(), ++it.base());
}

inline std::string trim_copy(const std::string& str)
{
    auto it1 = std::find_if(str.cbegin(), str.cend(),
        [](char ch) { return !std::isspace<char>(ch, std::locale::classic()); });
    if (it1 == str.cend()) {
        return std::string();
    }
    auto it2 = std::find_if(str.crbegin(), str.crend(),
        [](char ch) { return !std::isspace<char>(ch, std::locale::classic()); });
    return it2 == str.crend() ? std::string(it1, str.cend()) : std::string(it1, ++it2.base());
}

Javascript Src Path

Piece of cake!

<SCRIPT LANGUAGE="JavaScript" SRC="/clock.js"></SCRIPT>

Access POST values in Symfony2 request object

what worked for me was using this:

$data = $request->request->all();
$name = $data['form']['name'];

Insecure content in iframe on secure page

Based on generality of this question, I think, that you'll need to setup your own HTTPS proxy on some server online. Do the following steps:

  • Prepare your proxy server - install IIS, Apache
  • Get valid SSL certificate to avoid security errors (free from startssl.com for example)
  • Write a wrapper, which will download insecure content (how to below)
  • From your site/app get https://yourproxy.com/?page=http://insecurepage.com

If you simply download remote site content via file_get_contents or similiar, you can still have insecure links to content. You'll have to find them with regex and also replace. Images are hard to solve, but Ə found workaround here: http://foundationphp.com/tutorials/image_proxy.php


Note: While this solution may have worked in some browsers when it was written in 2014, it no longer works. Navigating or redirecting to an HTTP URL in an iframe embedded in an HTTPS page is not permitted by modern browsers, even if the frame started out with an HTTPS URL.

The best solution I created is to simply use google as the ssl proxy...

https://www.google.com/search?q=%http://yourhttpsite.com&btnI=Im+Feeling+Lucky

Tested and works in firefox.

Other Methods:

  • Use a Third party such as embed.ly (but it it really only good for well known http APIs).

  • Create your own redirect script on an https page you control (a simple javascript redirect on a relative linked page should do the trick. Something like: (you can use any langauge/method)

    https://example.com That has a iframe linking to...

    https://example.com/utilities/redirect.html Which has a simple js redirect script like...

    document.location.href ="http://thenonsslsite.com";

  • Alternatively, you could add an RSS feed or write some reader/parser to read the http site and display it within your https site.

  • You could/should also recommend to the http site owner that they create an ssl connection. If for no other reason than it increases seo.

Unless you can get the http site owner to create an ssl certificate, the most secure and permanent solution would be to create an RSS feed grabing the content you need (presumably you are not actually 'doing' anything on the http site -that is to say not logging in to any system).

The real issue is that having http elements inside a https site represents a security issue. There are no completely kosher ways around this security risk so the above are just current work arounds.

Note, that you can disable this security measure in most browsers (yourself, not for others). Also note that these 'hacks' may become obsolete over time.

How to bind DataTable to Datagrid

In cs file

DataTable employeeData = CreateDataTable();
gridEmployees.DataContext = employeeData.DefaultView;

In xaml file

<DataGrid Name="gridEmployees" ItemsSource="{Binding}">

Get all object attributes in Python?

I use __dict__

Example:

class MyObj(object):
  def __init__(self):
    self.name = 'Chuck Norris'
    self.phone = '+6661'

obj = MyObj()
print(obj.__dict__)

# Output:  
# {'phone': '+6661', 'name': 'Chuck Norris'}

How to set default Checked in checkbox ReactJS?

in addition to the correct answer you can just do :P

<input name="remember" type="checkbox" defaultChecked/>

Microsoft Excel mangles Diacritics in .csv files?

I've also noticed that the question was "answered" some time ago but I don't understand the stories that say you can't open a utf8-encoded csv file successfully in Excel without using the text wizard.

My reproducible experience: Type Old MacDonald had a farm,ƈƌƉƍƘ into Notepad, hit Enter, then Save As (using the UTF-8 option).

Using Python to show what's actually in there:

>>> open('oldmac.csv', 'rb').read()
'\xef\xbb\xbfOld MacDonald had a farm,\xc3\x88\xc3\x8c\xc3\x89\xc3\x8d\xc3\x98\r\n'
>>> ^Z

Good. Notepad has put a BOM at the front.

Now go into Windows Explorer, double click on the file name, or right click and use "Open with ...", and up pops Excel (2003) with display as expected.

How do I return multiple values from a function?

I prefer:

def g(x):
  y0 = x + 1
  y1 = x * 3
  y2 = y0 ** y3
  return {'y0':y0, 'y1':y1 ,'y2':y2 }

It seems everything else is just extra code to do the same thing.

VB.Net .Clear() or txtbox.Text = "" textbox clear methods

Clear() set the Text property to nothing. So txtbox1.Text = Nothing does the same thing as clear. An empty string (also available through String.Empty) is not a null reference, but has no value of course.

How to parse dates in multiple formats using SimpleDateFormat

What about just defining multiple patterns? They might come from a config file containing known patterns, hard coded it reads like:

List<SimpleDateFormat> knownPatterns = new ArrayList<SimpleDateFormat>();
knownPatterns.add(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"));
knownPatterns.add(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm.ss'Z'"));
knownPatterns.add(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss"));
knownPatterns.add(new SimpleDateFormat("yyyy-MM-dd' 'HH:mm:ss"));
knownPatterns.add(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX"));

for (SimpleDateFormat pattern : knownPatterns) {
    try {
        // Take a try
        return new Date(pattern.parse(candidate).getTime());

    } catch (ParseException pe) {
        // Loop on
    }
}
System.err.println("No known Date format found: " + candidate);
return null;

How do I access command line arguments in Python?

Some additional things that I can think of.

As @allsyed said sys.argv gives a list of components (including program name), so if you want to know the number of elements passed through command line you can use len() to determine it. Based on this, you can design exception/error messages if user didn't pass specific number of parameters.

Also if you looking for a better way to handle command line arguments, I would suggest you look at https://docs.python.org/2/howto/argparse.html

Jquery show/hide table rows

The filter function wasn't working for me at all; maybe the more recent version of jquery doesn't perform as the version used in above code. Regardless; I used:

    var black = $('.black');
    var white = $('.white');

The selector will find every element classed under black or white. Button functions stay as stated above:

    $('#showBlackButton').click(function() {
           black.show();
           white.hide();
    });

    $('#showWhiteButton').click(function() {
           white.show();
           black.hide();
    });

HTML tag inside JavaScript

JavaScript is a scripting language, not a HTMLanguage type. It is mainly to do process at background and it needs document.write to display things on browser. Also if your document.write exceeds one line, make sure to put concatenation + at the end of each line.

Example

<script type="text/javascript">
if(document.getElementById('number1').checked) {
document.write("<h1>Hello" +
"member</h1>");
}
</script>

Checking for empty or null List<string>

An easy way to combine myList == null || myList.Count == 0 would be to use the null coalescing operator ??:

if ((myList?.Count ?? 0) == 0) {
    //My list is null or empty
}

How do I use a pipe to redirect the output of one command to the input of another?

Not sure if you are coding these programs, but this is a simple example of how you'd do it.

program1.c

#include <stdio.h>
int main (int argc, char * argv[] ) {
    printf("%s", argv[1]); 
    return 0;
}

rgx.cpp

#include <cstdio>
#include <regex>
#include <iostream>
using namespace std;
int main (int argc, char * argv[] ) {
    char input[200];
    fgets(input,200,stdin);
    string s(input)
    smatch m;
    string reg_exp(argv[1]);
    regex e(reg_exp);
    while (regex_search (s,m,e)) {
      for (auto x:m) cout << x << " ";
      cout << endl;
      s = m.suffix().str();
    }
    return 0;
}

Compile both then run program1.exe "this subject has a submarine as a subsequence" | rgx.exe "\b(sub)([^ ]*)"

The | operator simply redirects the output of program1's printf operation from the stdout stream to the stdin stream whereby it's sitting there waiting for rgx.exe to pick up.

json and empty array

The first version is a null object while the second is an Array object with zero elements.

Null may mean here for example that no location is available for that user, no location has been requested or that some restrictions apply. Hard to tell with no reference to the API.

Spring-boot default profile for integration tests

If you use maven, you can add this in pom.xml:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-failsafe-plugin</artifactId>
            <configuration>
                <argLine>-Dspring.profiles.active=test</argLine>
            </configuration>
        </plugin>
        ...

Then, maven should run your integration tests (*IT.java) using this arugument, and also IntelliJ will start with this profile activated - so you can then specify all properties inside

application-test.yml

and you should not need "-default" properties.

/usr/bin/ld: cannot find

Add -L/opt/lib to your compiler parameters, this makes the compiler and linker search that path for libcalc.so in that folder.

How to get absolute value from double - c-language

I have found that using cabs(double), cabsf(float), cabsl(long double), __cabsf(float), __cabs(double), __cabsf(long double) is the solution

Powershell script to see currently logged in users (domain and machine) + status (active, idle, away)

In search of this same solution, I found what I needed under a different question in stackoverflow: Powershell-log-off-remote-session. The below one line will return a list of logged on users.

query user /server:$SERVER

Obtaining only the filename when using OpenFileDialog property "FileName"

Use OpenFileDialog.SafeFileName

OpenFileDialog.SafeFileName Gets the file name and extension for the file selected in the dialog box. The file name does not include the path.

Any free WPF themes?

You might want to try www.reuxables.com - we have both commercial and free themes, and it is the largest and most diverse theme library for WPF.

How is Perl's @INC constructed? (aka What are all the ways of affecting where Perl modules are searched for?)

We will look at how the contents of this array are constructed and can be manipulated to affect where the Perl interpreter will find the module files.

  1. Default @INC

    Perl interpreter is compiled with a specific @INC default value. To find out this value, run env -i perl -V command (env -i ignores the PERL5LIB environmental variable - see #2) and in the output you will see something like this:

    $ env -i perl -V
    ...
    @INC:
     /usr/lib/perl5/site_perl/5.18.0/x86_64-linux-thread-multi-ld
     /usr/lib/perl5/site_perl/5.18.0
     /usr/lib/perl5/5.18.0/x86_64-linux-thread-multi-ld
     /usr/lib/perl5/5.18.0
     .
    

Note . at the end; this is the current directory (which is not necessarily the same as the script's directory). It is missing in Perl 5.26+, and when Perl runs with -T (taint checks enabled).

To change the default path when configuring Perl binary compilation, set the configuration option otherlibdirs:

Configure -Dotherlibdirs=/usr/lib/perl5/site_perl/5.16.3

  1. Environmental variable PERL5LIB (or PERLLIB)

    Perl pre-pends @INC with a list of directories (colon-separated) contained in PERL5LIB (if it is not defined, PERLLIB is used) environment variable of your shell. To see the contents of @INC after PERL5LIB and PERLLIB environment variables have taken effect, run perl -V.

    $ perl -V
    ...
    %ENV:
      PERL5LIB="/home/myuser/test"
    @INC:
     /home/myuser/test
     /usr/lib/perl5/site_perl/5.18.0/x86_64-linux-thread-multi-ld
     /usr/lib/perl5/site_perl/5.18.0
     /usr/lib/perl5/5.18.0/x86_64-linux-thread-multi-ld
     /usr/lib/perl5/5.18.0
     .
    
  2. -I command-line option

    Perl pre-pends @INC with a list of directories (colon-separated) passed as value of the -I command-line option. This can be done in three ways, as usual with Perl options:

    • Pass it on command line:

      perl -I /my/moduledir your_script.pl
      
    • Pass it via the first line (shebang) of your Perl script:

      #!/usr/local/bin/perl -w -I /my/moduledir
      
    • Pass it as part of PERL5OPT (or PERLOPT) environment variable (see chapter 19.02 in Programming Perl)

  3. Pass it via the lib pragma

    Perl pre-pends @INC with a list of directories passed in to it via use lib.

    In a program:

    use lib ("/dir1", "/dir2");
    

    On the command line:

    perl -Mlib=/dir1,/dir2
    

    You can also remove the directories from @INC via no lib.

  4. You can directly manipulate @INC as a regular Perl array.

    Note: Since @INC is used during the compilation phase, this must be done inside of a BEGIN {} block, which precedes the use MyModule statement.

    • Add directories to the beginning via unshift @INC, $dir.

    • Add directories to the end via push @INC, $dir.

    • Do anything else you can do with a Perl array.

Note: The directories are unshifted onto @INC in the order listed in this answer, e.g. default @INC is last in the list, preceded by PERL5LIB, preceded by -I, preceded by use lib and direct @INC manipulation, the latter two mixed in whichever order they are in Perl code.

References:

There does not seem to be a comprehensive @INC FAQ-type post on Stack Overflow, so this question is intended as one.

When to use each approach?

  • If the modules in a directory need to be used by many/all scripts on your site, especially run by multiple users, that directory should be included in the default @INC compiled into the Perl binary.

  • If the modules in the directory will be used exclusively by a specific user for all the scripts that user runs (or if recompiling Perl is not an option to change default @INC in previous use case), set the users' PERL5LIB, usually during user login.

    Note: Please be aware of the usual Unix environment variable pitfalls - e.g. in certain cases running the scripts as a particular user does not guarantee running them with that user's environment set up, e.g. via su.

  • If the modules in the directory need to be used only in specific circumstances (e.g. when the script(s) is executed in development/debug mode, you can either set PERL5LIB manually, or pass the -I option to perl.

  • If the modules need to be used only for specific scripts, by all users using them, use use lib/no lib pragmas in the program itself. It also should be used when the directory to be searched needs to be dynamically determined during runtime - e.g. from the script's command line parameters or script's path (see the FindBin module for very nice use case).

  • If the directories in @INC need to be manipulated according to some complicated logic, either impossible to too unwieldy to implement by combination of use lib/no lib pragmas, then use direct @INC manipulation inside BEGIN {} block or inside a special purpose library designated for @INC manipulation, which must be used by your script(s) before any other modules are used.

    An example of this is automatically switching between libraries in prod/uat/dev directories, with waterfall library pickup in prod if it's missing from dev and/or UAT (the last condition makes the standard "use lib + FindBin" solution fairly complicated. A detailed illustration of this scenario is in How do I use beta Perl modules from beta Perl scripts?.

  • An additional use case for directly manipulating @INC is to be able to add subroutine references or object references (yes, Virginia, @INC can contain custom Perl code and not just directory names, as explained in When is a subroutine reference in @INC called?).

How can I bind a background color in WPF/XAML?

I recommend reading the following blog post about debugging data binding: http://beacosta.com/blog/?p=52

And for this concrete issue: If you look at the compiler warnings, you will notice that you property has been hiding the Window.Background property (or Control or whatever class the property defines).

Difference between the annotations @GetMapping and @RequestMapping(method = RequestMethod.GET)

@RequestMapping is a class level

@GetMapping is a method-level

With sprint Spring 4.3. and up things have changed. Now you can use @GetMapping on the method that will handle the http request. The class-level @RequestMapping specification is refined with the (method-level)@GetMapping annotation

Here is an example:

@Slf4j
@Controller
@RequestMapping("/orders")/* The @Request-Mapping annotation, when applied
                            at the class level, specifies the kind of requests 
                            that this controller handles*/  

public class OrderController {

@GetMapping("/current")/*@GetMapping paired with the classlevel
                        @RequestMapping, specifies that when an 
                        HTTP GET request is received for /order, 
                        orderForm() will be called to handle the request..*/

public String orderForm(Model model) {

model.addAttribute("order", new Order());

return "orderForm";
}
}

Prior to Spring 4.3, it was @RequestMapping(method=RequestMethod.GET)

Extra reading from a book authored by Craig Walls Extra reading from a book authored by Craig Walls

How do I get LaTeX to hyphenate a word that contains a dash?

To avoid hyphenation in already hyphenated word I used non-breaking space ~ in combination with backward space \!. For example, command

3~\!\!\!\!-~\!\!\!D

used in the text, suppress hyphenation in word 3-D. Probably not the best solution, but it worked for me!

How to create an ArrayList from an Array in PowerShell?

I can't get that constructor to work either. This however seems to work:

# $temp = Get-ResourceFiles
$resourceFiles = New-Object System.Collections.ArrayList($null)
$resourceFiles.AddRange($temp)

You can also pass an integer in the constructor to set an initial capacity.

What do you mean when you say you want to enumerate the files? Why can't you just filter the wanted values into a fresh array?

Edit:

It seems that you can use the array constructor like this:

$resourceFiles = New-Object System.Collections.ArrayList(,$someArray)

Note the comma. I believe what is happening is that when you call a .NET method, you always pass parameters as an array. PowerShell unpacks that array and passes it to the method as separate parameters. In this case, we don't want PowerShell to unpack the array; we want to pass the array as a single unit. Now, the comma operator creates arrays. So PowerShell unpacks the array, then we create the array again with the comma operator. I think that is what is going on.

Git Push ERROR: Repository not found

Have experienced the same problem. Everything was working fine for years and then suddenly this error.

The problem turns out was that I added a deploy key for another repo to my SSH agent before my user's github SSH key (which I always used to access the repo in question). SSH agent tried the deploy key for another repo first, and GitHub for some totally unexplainable reason was saying

ERROR: Repository not found.

Once I've removed the deploy key from SSH agent, everything was back to normal.

Get selected option from select element

This worked for me:

$("#SelectedCountryId_option_selected")[0].textContent

Jquery: How to check if the element has certain css class/style

if ($("element class or id name").css("property") == "value") {
    your code....
}

What is the difference between attribute and property?

These words existed way before Computer Science came around.

  1. Attribute is a quality or object that we attribute to someone or something. For example, the scepter is an attribute of power and statehood.

  2. Property is a quality that exists without any attribution. For example, clay has adhesive qualities; i.e, a property of clay is its adhesive quality. Another example: one of the properties of metals is electrical conductivity. Properties demonstrate themselves through physical phenomena without the need to attribute them to someone or something. By the same token, saying that someone has masculine attributes is self-evident. In effect, you could say that a property is owned by someone or something.

To be fair though, in Computer Science these two words, at least for the most part, can be used interchangeably - but then again programmers usually don't hold degrees in English Literature and do not write or care much about grammar books :).

What is ADT? (Abstract Data Type)

A truly abstract data type describes the properties of its instances without commitment to their representation or particular operations. For example the abstract (mathematical) type Integer is a discrete, unlimited, linearly ordered set of instances. A concrete type gives a specific representation for instances and implements a specific set of operations.

How to assign more memory to docker container

If you want to change the default container and you are using Virtualbox, you can do it via the commandline / CLI:

docker-machine stop
VBoxManage modifyvm default --cpus 2
VBoxManage modifyvm default --memory 4096
docker-machine start

How to sort a NSArray alphabetically?

-(IBAction)SegmentbtnCLK:(id)sender
{ [self sortArryofDictionary];
    [self.objtable reloadData];}
-(void)sortArryofDictionary
{ NSSortDescriptor *sorter;
    switch (sortcontrol.selectedSegmentIndex)
    {case 0:
            sorter=[[NSSortDescriptor alloc]initWithKey:@"Name" ascending:YES];
            break;
        case 1:
            sorter=[[NSSortDescriptor alloc]initWithKey:@"Age" ascending:YES];
            default:
            break; }
    NSArray *sortdiscriptor=[[NSArray alloc]initWithObjects:sorter, nil];
    [arr sortUsingDescriptors:sortdiscriptor];
    }

If Else in LINQ

This might work...

from p in db.products
    select new
    {
        Owner = (p.price > 0 ?
            from q in db.Users select q.Name :
            from r in db.ExternalUsers select r.Name)
    }

Lombok added but getters and setters not recognized in Intellij IDEA

Goto Setting->Plugin->Search for "Lombok Plugin" -> It will show results. Install Lombok Plugin from the list and Restart Intellij

Using Font Awesome icon for bullet points, with a single list item element

My solution using standard <ul> and <i> inside <li>

  <ul>
    <li><i class="fab fa-cc-paypal"></i> <div>Paypal</div></li>
    <li><i class="fab fa-cc-apple-pay"></i> <div>Apple Pay</div></li>
    <li><i class="fab fa-cc-stripe"></i> <div>Stripe</div></li>
    <li><i class="fab fa-cc-visa"></i> <div>VISA</div></li>
  </ul>

enter image description here

DEMO HERE

What is "Advanced" SQL?

At my previous job, we had a technical test which all candidates were asked to sit. 10ish questions, took about an hour. In all honesty though, 90% of failures could be screened out because they couldn't write an INNER JOIN statement. Not even an outer.

I'd consider that a prerequisite for any job description involving SQL and would leave well alone until that was mastered. From there though, talk to them - any further info on what they're actually looking for will, worst case scenario, be a useful list of things to learn as part of your professional development.

How to run a command as a specific user in an init script?

I usually do it the way that you are doing it (i.e. sudo -u username command). But, there is also the 'djb' way to run a daemon with privileges of another user. See: http://thedjbway.b0llix.net/daemontools/uidgid.html

npm install error - MSB3428: Could not load the Visual C++ component "VCBuild.exe"

Tried npm install mongoose --msvs_version=2012, if you have multiple Visual installed, it worked for me

How to edit CSS style of a div using C# in .NET

How do you do this without runat="server"? For example, if you have a

<body runat="server" id="body1">

...and try to update it from within an Updatepanel it will never get updated.

However, if you keep it as an ordinary non-server HTML control you can. Here's the Jquery to update it:

$("#body1").addClass('modalBackground');

How do you do this in codebehind though?

package javax.mail and javax.mail.internet do not exist

  1. Download the Java mail jars.

  2. Extract the downloaded file.

  3. Copy the ".jar" file and paste it into ProjectName\WebContent\WEB-INF\lib folder

  4. Right click on the Project and go to Properties

  5. Select Java Build Path and then select Libraries

  6. Add JARs...

  7. Select the .jar file from ProjectName\WebContent\WEB-INF\lib and click OK

    that's all

How to automatically import data from uploaded CSV or XLS file into Google Sheets

You can programmatically import data from a csv file in your Drive into an existing Google Sheet using Google Apps Script, replacing/appending data as needed.

Below is some sample code. It assumes that: a) you have a designated folder in your Drive where the CSV file is saved/uploaded to; b) the CSV file is named "report.csv" and the data in it comma-delimited; and c) the CSV data is imported into a designated spreadsheet. See comments in code for further details.

function importData() {
  var fSource = DriveApp.getFolderById(reports_folder_id); // reports_folder_id = id of folder where csv reports are saved
  var fi = fSource.getFilesByName('report.csv'); // latest report file
  var ss = SpreadsheetApp.openById(data_sheet_id); // data_sheet_id = id of spreadsheet that holds the data to be updated with new report data

  if ( fi.hasNext() ) { // proceed if "report.csv" file exists in the reports folder
    var file = fi.next();
    var csv = file.getBlob().getDataAsString();
    var csvData = CSVToArray(csv); // see below for CSVToArray function
    var newsheet = ss.insertSheet('NEWDATA'); // create a 'NEWDATA' sheet to store imported data
    // loop through csv data array and insert (append) as rows into 'NEWDATA' sheet
    for ( var i=0, lenCsv=csvData.length; i<lenCsv; i++ ) {
      newsheet.getRange(i+1, 1, 1, csvData[i].length).setValues(new Array(csvData[i]));
    }
    /*
    ** report data is now in 'NEWDATA' sheet in the spreadsheet - process it as needed,
    ** then delete 'NEWDATA' sheet using ss.deleteSheet(newsheet)
    */
    // rename the report.csv file so it is not processed on next scheduled run
    file.setName("report-"+(new Date().toString())+".csv");
  }
};


// http://www.bennadel.com/blog/1504-Ask-Ben-Parsing-CSV-Strings-With-Javascript-Exec-Regular-Expression-Command.htm
// This will parse a delimited string into an array of
// arrays. The default delimiter is the comma, but this
// can be overriden in the second argument.

function CSVToArray( strData, strDelimiter ) {
  // Check to see if the delimiter is defined. If not,
  // then default to COMMA.
  strDelimiter = (strDelimiter || ",");

  // Create a regular expression to parse the CSV values.
  var objPattern = new RegExp(
    (
      // Delimiters.
      "(\\" + strDelimiter + "|\\r?\\n|\\r|^)" +

      // Quoted fields.
      "(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|" +

      // Standard fields.
      "([^\"\\" + strDelimiter + "\\r\\n]*))"
    ),
    "gi"
  );

  // Create an array to hold our data. Give the array
  // a default empty first row.
  var arrData = [[]];

  // Create an array to hold our individual pattern
  // matching groups.
  var arrMatches = null;

  // Keep looping over the regular expression matches
  // until we can no longer find a match.
  while (arrMatches = objPattern.exec( strData )){

    // Get the delimiter that was found.
    var strMatchedDelimiter = arrMatches[ 1 ];

    // Check to see if the given delimiter has a length
    // (is not the start of string) and if it matches
    // field delimiter. If id does not, then we know
    // that this delimiter is a row delimiter.
    if (
      strMatchedDelimiter.length &&
      (strMatchedDelimiter != strDelimiter)
    ){

      // Since we have reached a new row of data,
      // add an empty row to our data array.
      arrData.push( [] );

    }

    // Now that we have our delimiter out of the way,
    // let's check to see which kind of value we
    // captured (quoted or unquoted).
    if (arrMatches[ 2 ]){

      // We found a quoted value. When we capture
      // this value, unescape any double quotes.
      var strMatchedValue = arrMatches[ 2 ].replace(
        new RegExp( "\"\"", "g" ),
        "\""
      );

    } else {

      // We found a non-quoted value.
      var strMatchedValue = arrMatches[ 3 ];

    }

    // Now that we have our value string, let's add
    // it to the data array.
    arrData[ arrData.length - 1 ].push( strMatchedValue );
  }

  // Return the parsed data.
  return( arrData );
};

You can then create time-driven trigger in your script project to run importData() function on a regular basis (e.g. every night at 1AM), so all you have to do is put new report.csv file into the designated Drive folder, and it will be automatically processed on next scheduled run.

If you absolutely MUST work with Excel files instead of CSV, then you can use this code below. For it to work you must enable Drive API in Advanced Google Services in your script and in Developers Console (see How to Enable Advanced Services for details).

/**
 * Convert Excel file to Sheets
 * @param {Blob} excelFile The Excel file blob data; Required
 * @param {String} filename File name on uploading drive; Required
 * @param {Array} arrParents Array of folder ids to put converted file in; Optional, will default to Drive root folder
 * @return {Spreadsheet} Converted Google Spreadsheet instance
 **/
function convertExcel2Sheets(excelFile, filename, arrParents) {

  var parents  = arrParents || []; // check if optional arrParents argument was provided, default to empty array if not
  if ( !parents.isArray ) parents = []; // make sure parents is an array, reset to empty array if not

  // Parameters for Drive API Simple Upload request (see https://developers.google.com/drive/web/manage-uploads#simple)
  var uploadParams = {
    method:'post',
    contentType: 'application/vnd.ms-excel', // works for both .xls and .xlsx files
    contentLength: excelFile.getBytes().length,
    headers: {'Authorization': 'Bearer ' + ScriptApp.getOAuthToken()},
    payload: excelFile.getBytes()
  };

  // Upload file to Drive root folder and convert to Sheets
  var uploadResponse = UrlFetchApp.fetch('https://www.googleapis.com/upload/drive/v2/files/?uploadType=media&convert=true', uploadParams);

  // Parse upload&convert response data (need this to be able to get id of converted sheet)
  var fileDataResponse = JSON.parse(uploadResponse.getContentText());

  // Create payload (body) data for updating converted file's name and parent folder(s)
  var payloadData = {
    title: filename, 
    parents: []
  };
  if ( parents.length ) { // Add provided parent folder(s) id(s) to payloadData, if any
    for ( var i=0; i<parents.length; i++ ) {
      try {
        var folder = DriveApp.getFolderById(parents[i]); // check that this folder id exists in drive and user can write to it
        payloadData.parents.push({id: parents[i]});
      }
      catch(e){} // fail silently if no such folder id exists in Drive
    }
  }
  // Parameters for Drive API File Update request (see https://developers.google.com/drive/v2/reference/files/update)
  var updateParams = {
    method:'put',
    headers: {'Authorization': 'Bearer ' + ScriptApp.getOAuthToken()},
    contentType: 'application/json',
    payload: JSON.stringify(payloadData)
  };

  // Update metadata (filename and parent folder(s)) of converted sheet
  UrlFetchApp.fetch('https://www.googleapis.com/drive/v2/files/'+fileDataResponse.id, updateParams);

  return SpreadsheetApp.openById(fileDataResponse.id);
}

/**
 * Sample use of convertExcel2Sheets() for testing
 **/
 function testConvertExcel2Sheets() {
  var xlsId = "0B9**************OFE"; // ID of Excel file to convert
  var xlsFile = DriveApp.getFileById(xlsId); // File instance of Excel file
  var xlsBlob = xlsFile.getBlob(); // Blob source of Excel file for conversion
  var xlsFilename = xlsFile.getName(); // File name to give to converted file; defaults to same as source file
  var destFolders = []; // array of IDs of Drive folders to put converted file in; empty array = root folder
  var ss = convertExcel2Sheets(xlsBlob, xlsFilename, destFolders);
  Logger.log(ss.getId());
}

The above code is also available as a gist here.

Android Gradle Apache HttpClient does not exist?

Basically all you need to do is add:

useLibrary  'org.apache.http.legacy'

To your build.gradle file.

Adding Buttons To Google Sheets and Set value to Cells on clicking

Consider building an Add-on that has an actual button and not using the outdated method of linking an image to a script function.

In the script editor, under the Help menu >> Welcome Screen >> link to Google Sheets Add-on - will give you sample code to use.

How to use php serialize() and unserialize()

A PHP array or object or other complex data structure cannot be transported or stored or otherwise used outside of a running PHP script. If you want to persist such a complex data structure beyond a single run of a script, you need to serialize it. That just means to put the structure into a "lower common denominator" that can be handled by things other than PHP, like databases, text files, sockets. The standard PHP function serialize is just a format to express such a thing, it serializes a data structure into a string representation that's unique to PHP and can be reversed into a PHP object using unserialize. There are many other formats though, like JSON or XML.


Take for example this common problem:

How do I pass a PHP array to Javascript?

PHP and Javascript can only communicate via strings. You can pass the string "foo" very easily to Javascript. You can pass the number 1 very easily to Javascript. You can pass the boolean values true and false easily to Javascript. But how do you pass this array to Javascript?

Array ( [1] => elem 1 [2] => elem 2 [3] => elem 3 ) 

The answer is serialization. In case of PHP/Javascript, JSON is actually the better serialization format:

{ 1 : 'elem 1', 2 : 'elem 2', 3 : 'elem 3' }

Javascript can easily reverse this into an actual Javascript array.

This is just as valid a representation of the same data structure though:

a:3:{i:1;s:6:"elem 1";i:2;s:6:"elem 2";i:3;s:7:" elem 3";}

But pretty much only PHP uses it, there's little support for this format anywhere else.
This is very common and well supported as well though:

<array>
    <element key='1'>elem 1</element>
    <element key='2'>elem 2</element>
    <element key='3'>elem 3</element>
</array>

There are many situations where you need to pass complex data structures around as strings. Serialization, representing arbitrary data structures as strings, solves how to do this.

What does it mean to "program to an interface"?

So, just to get this right, the advantage of a interface is that I can separate the calling of a method from any particular class. Instead creating a instance of the interface, where the implementation is given from whichever class I choose that implements that interface. Thus allowing me to have many classes, which have similar but slightly different functionality and in some cases (the cases related to the intention of the interface) not care which object it is.

For example, I could have a movement interface. A method which makes something 'move' and any object (Person, Car, Cat) that implements the movement interface could be passed in and told to move. Without the method every knowing the type of class it is.

How do you join on the same table, twice, in mysql?

Given the following tables..

Domain Table
dom_id | dom_url

Review Table
rev_id | rev_dom_from | rev_dom_for

Try this sql... (It's pretty much the same thing that Stephen Wrighton wrote above) The trick is that you are basically selecting from the domain table twice in the same query and joining the results.

Select d1.dom_url, d2.dom_id from
review r, domain d1, domain d2
where d1.dom_id = r.rev_dom_from
and d2.dom_id = r.rev_dom_for

If you are still stuck, please be more specific with exactly it is that you don't understand.

SQL Server - Adding a string to a text column (concat equivalent)

To Join two string in SQL Query use function CONCAT(Express1,Express2,...)

Like....

SELECT CODE, CONCAT(Rtrim(FName), " " , TRrim(LName)) as Title FROM MyTable

JavaScript - get the first day of the week from current date

CMS's answer is correct but assumes that Monday is the first day of the week.
Chandler Zwolle's answer is correct but fiddles with the Date prototype.
Other answers that play with hour/minutes/seconds/milliseconds are wrong.

The function below is correct and takes a date as first parameter and the desired first day of the week as second parameter (0 for Sunday, 1 for Monday, etc.). Note: the hour, minutes and seconds are set to 0 to have the beginning of the day.

_x000D_
_x000D_
function firstDayOfWeek(dateObject, firstDayOfWeekIndex) {_x000D_
_x000D_
    const dayOfWeek = dateObject.getDay(),_x000D_
        firstDayOfWeek = new Date(dateObject),_x000D_
        diff = dayOfWeek >= firstDayOfWeekIndex ?_x000D_
            dayOfWeek - firstDayOfWeekIndex :_x000D_
            6 - dayOfWeek_x000D_
_x000D_
    firstDayOfWeek.setDate(dateObject.getDate() - diff)_x000D_
    firstDayOfWeek.setHours(0,0,0,0)_x000D_
_x000D_
    return firstDayOfWeek_x000D_
}_x000D_
_x000D_
// August 18th was a Saturday_x000D_
let lastMonday = firstDayOfWeek(new Date('August 18, 2018 03:24:00'), 1)_x000D_
_x000D_
// outputs something like "Mon Aug 13 2018 00:00:00 GMT+0200"_x000D_
// (may vary according to your time zone)_x000D_
document.write(lastMonday)
_x000D_
_x000D_
_x000D_

Create a CSS rule / class with jQuery at runtime

Adding custom rules is useful if you create a jQuery widget that requires custom CSS (such as extending the existing jQueryUI CSS framework for your particular widget). This solution builds on Taras's answer (the first one above).

Assuming your HTML markup has a button with an id of "addrule" and a div with an id of "target" containing some text:

jQuery code:

$( "#addrule" ).click(function () { addcssrule($("#target")); });

function addcssrule(target) 
{ 
var cssrules =  $("<style type='text/css'> </style>").appendTo("head");

cssrules.append(".redbold{ color:#f00; font-weight:bold;}"); 
cssrules.append(".newfont {font-family: arial;}"); 
target.addClass("redbold newfont");     
}       

The advantage of this approach is that you can reuse variable cssrules in your code to add or subtract rules at will. If cssrules is embedded in a persistent object such as a jQuery widget you have a persistent local variable to work with.

How to concat two ArrayLists?

You can use .addAll() to add the elements of the second list to the first:

array1.addAll(array2);

Edit: Based on your clarification above ("i want a single String in the new Arraylist which has both name and number."), you would want to loop through the first list and append the item from the second list to it.

Something like this:

int length = array1.size();
if (length != array2.size()) { // Too many names, or too many numbers
    // Fail
}
ArrayList<String> array3 = new ArrayList<String>(length); // Make a new list
for (int i = 0; i < length; i++) { // Loop through every name/phone number combo
    array3.add(array1.get(i) + " " + array2.get(i)); // Concat the two, and add it
}

If you put in:

array1 : ["a", "b", "c"]
array2 : ["1", "2", "3"]

You will get:

array3 : ["a 1", "b 2", "c 3"]

Why can't Python find shared objects that are in directories in sys.path?

Ensure your libcurl.so module is in the system library path, which is distinct and separate from the python library path.

A "quick fix" is to add this path to a LD_LIBRARY_PATH variable. However, setting that system wide (or even account wide) is a BAD IDEA, as it is possible to set it in such a way that some programs will find a library it shouldn't, or even worse, open up security holes.

If your "locally installed libraries" are installed in, for example, /usr/local/lib, add this directory to /etc/ld.so.conf (it's a text file) and run "ldconfig"

The command will run a caching utility, but will also create all the necessary "symbolic links" required for the loader system to function. It is surprising that the "make install" for libcurl did not do this already, but it's possible it could not if /usr/local/lib is not in /etc/ld.so.conf already.

PS: it's possible that your /etc/ld.so.conf contains nothing but "include ld.so.conf.d/*.conf". You can still add a directory path after it, or just create a new file inside the directory it's being included from. Dont forget to run "ldconfig" after it.

Be careful. Getting this wrong can screw up your system.

Additionally: make sure your python module is compiled against THAT version of libcurl. If you just copied some files over from another system, this wont always work. If in doubt, compile your modules on the system you intend to run them on.

SQL Server Insert Example

I hope this will help you

Create table :

create table users (id int,first_name varchar(10),last_name varchar(10));

Insert values into the table :

insert into users (id,first_name,last_name) values(1,'Abhishek','Anand');

Check if all checkboxes are selected

This is how I achieved it in my code:

if($('.citiescheckbox:checked').length == $('.citiescheckbox').length){
    $('.citycontainer').hide();
}else{
    $('.citycontainer').show();
}

How to map and remove nil values in Ruby

Ruby 2.7+

There is now!

Ruby 2.7 is introducing filter_map for this exact purpose. It's idiomatic and performant, and I'd expect it to become the norm very soon.

For example:

numbers = [1, 2, 5, 8, 10, 13]
enum.filter_map { |i| i * 2 if i.even? }
# => [4, 16, 20]

In your case, as the block evaluates to falsey, simply:

items.filter_map { |x| process_x url }

"Ruby 2.7 adds Enumerable#filter_map" is a good read on the subject, with some performance benchmarks against some of the earlier approaches to this problem:

N = 100_000
enum = 1.upto(1_000)
Benchmark.bmbm do |x|
  x.report("select + map")  { N.times { enum.select { |i| i.even? }.map{ |i| i + 1 } } }
  x.report("map + compact") { N.times { enum.map { |i| i + 1 if i.even? }.compact } }
  x.report("filter_map")    { N.times { enum.filter_map { |i| i + 1 if i.even? } } }
end

# Rehearsal -------------------------------------------------
# select + map    8.569651   0.051319   8.620970 (  8.632449)
# map + compact   7.392666   0.133964   7.526630 (  7.538013)
# filter_map      6.923772   0.022314   6.946086 (  6.956135)
# --------------------------------------- total: 23.093686sec
# 
#                     user     system      total        real
# select + map    8.550637   0.033190   8.583827 (  8.597627)
# map + compact   7.263667   0.131180   7.394847 (  7.405570)
# filter_map      6.761388   0.018223   6.779611 (  6.790559)

Combine two or more columns in a dataframe into a new column with a new name

Some examples with NAs and their removal using apply

n = c(2, NA, NA) 
s = c("aa", "bb", NA) 
b = c(TRUE, FALSE, NA) 
c = c(2, 3, 5) 
d = c("aa", NA, "cc") 
e = c(TRUE, NA, TRUE) 
df = data.frame(n, s, b, c, d, e)

paste_noNA <- function(x,sep=", ") {
gsub(", " ,sep, toString(x[!is.na(x) & x!="" & x!="NA"] ) ) }

sep=" "
df$x <- apply( df[ , c(1:6) ] , 1 , paste_noNA , sep=sep)
df

How to center images on a web page for all screen sizes

text-align:center

Applying the text-align:center style to an element containing elements will center those elements.

<div id="method-one" style="text-align:center">
  CSS `text-align:center`
</div>

Thomas Shields mentions this method



margin:0 auto

Applying the margin:0 auto style to a block element will center it within the element it is in.

<div id="method-two" style="background-color:green">
  <div style="margin:0 auto;width:50%;background-color:lightblue">
    CSS `margin:0 auto` to have left and right margin set to center a block element within another element.
  </div>
</div>

user1468562 mentions this method


Center tag

My original answer was that you can use the <center></center> tag. To do this, just place the content you want centered between the tags. As of HTML4, this tag has been deprecated, though. <center> is still technically supported today (9 years later at the time of updating this), but I'd recommend the CSS alternatives I've included above.

<h3>Method 3</h1>
<div id="method-three">
  <center>Center tag (not recommended and deprecated in HTML4)</center>
</div>

You can see these three code samples in action in this jsfiddle.

I decided I should revise this answer as the previous one I gave was outdated. It was already deprecated when I suggested it as a solution and that's all the more reason to avoid it now 9 years later.

How to escape a single quote inside awk

For small scripts an optional way to make it readable is to use a variable like this:

awk -v fmt="'%s'\n" '{printf fmt, $1}'

I found it conveninet in a case where I had to produce many times the single-quote character in the output and the \047 were making it totally unreadable

Setting environment variables on OS X

Sometimes all of the previous answers simply don't work. If you want to have access to a system variable (like M2_HOME) in Eclipse or in IntelliJ IDEA the only thing that works for me in this case is:

First (step 1) edit /etc/launchd.conf to contain a line like this: "setenv VAR value" and then (step 2) reboot.

Simply modifying .bash_profile won't work because in OS X the applications are not started as in other Unix'es; they don't inherit the parent's shell variables. All the other modifications won't work for a reason that is unknown to me. Maybe someone else can clarify about this.

How do I drag and drop files into an application?

Yet another gotcha:

The framework code that calls the Drag-events swallow all exceptions. You might think your event code is running smoothly, while it is gushing exceptions all over the place. You can't see them because the framework steals them.

That's why I always put a try/catch in these event handlers, just so I know if they throw any exceptions. I usually put a Debugger.Break(); in the catch part.

Before release, after testing, if everything seems to behave, I remove or replace these with real exception handling.

How can I convert a file pointer ( FILE* fp ) to a file descriptor (int fd)?

Even if fileno(FILE *) may return a file descriptor, be VERY careful not to bypass stdio's buffer. If there is buffer data (either read or unflushed write), reads/writes from the file descriptor might give you unexpected results.

To answer one of the side questions, to convert a file descriptor to a FILE pointer, use fdopen(3)

Create an empty list in python with certain size

You can .append(element) to the list, e.g.: s1.append(i). What you are currently trying to do is access an element (s1[i]) that does not exist.

Count records for every month in a year

SELECT    COUNT(*) 
FROM      table_emp 
WHERE     YEAR(ARR_DATE) = '2012' 
GROUP BY  MONTH(ARR_DATE)

Edit existing excel workbooks and sheets with xlrd and xlwt

Here's another way of doing the code above using the openpyxl module that's compatible with xlsx. From what I've seen so far, it also keeps formatting.

from openpyxl import load_workbook
wb = load_workbook('names.xlsx')
ws = wb['SheetName']
ws['A1'] = 'A1'
wb.save('names.xlsx')

Inline functions in C#?

Finally in .NET 4.5, the CLR allows one to hint/suggest1 method inlining using MethodImplOptions.AggressiveInlining value. It is also available in the Mono's trunk (committed today).

// The full attribute usage is in mscorlib.dll,
// so should not need to include extra references
using System.Runtime.CompilerServices; 

...

[MethodImpl(MethodImplOptions.AggressiveInlining)]
void MyMethod(...)

1. Previously "force" was used here. Since there were a few downvotes, I'll try to clarify the term. As in the comments and the documentation, The method should be inlined if possible. Especially considering Mono (which is open), there are some mono-specific technical limitations considering inlining or more general one (like virtual functions). Overall, yes, this is a hint to compiler, but I guess that is what was asked for.

How to bind a List<string> to a DataGridView control?

Thats because DataGridView looks for properties of containing objects. For string there is just one property - length. So, you need a wrapper for a string like this

public class StringValue
{
    public StringValue(string s)
    {
        _value = s;
    }
    public string Value { get { return _value; } set { _value = value; } }
    string _value;
}

Then bind List<StringValue> object to your grid. It works

How do I select an entire row which has the largest ID in the table?

You could use a subselect:

SELECT row 
FROM table 
WHERE id=(
    SELECT max(id) FROM table
    )

Note that if the value of max(id) is not unique, multiple rows are returned.

If you only want one such row, use @MichaelMior's answer,

SELECT row from table ORDER BY id DESC LIMIT 1

How to improve performance of ngRepeat over a huge dataset (angular.js)?

I recommend to see this:

Optimizing AngularJS: 1200ms to 35ms

they made a new directive by optimizing ng-repeat at 4 parts:

Optimization#1: Cache DOM elements

Optimization#2: Aggregate watchers

Optimization#3: Defer element creation

Optimization#4: Bypass watchers for hidden elements

the project is here on github:

Usage:

1- include these files in your single-page app:

  • core.js
  • scalyr.js
  • slyEvaluate.js
  • slyRepeat.js

2- add module dependency:

var app = angular.module("app", ['sly']);

3- replace ng-repeat

<tr sly-repeat="m in rows"> .....<tr>

ENjoY!

add a string prefix to each value in a string column using Pandas

If you load you table file with dtype=str
or convert column type to string df['a'] = df['a'].astype(str)
then you can use such approach:

df['a']= 'col' + df['a'].str[:]

This approach allows prepend, append, and subset string of df.
Works on Pandas v0.23.4, v0.24.1. Don't know about earlier versions.

Using sed to split a string with a delimiter

This might work for you (GNU sed):

sed 'y/:/\n/' file

or perhaps:

sed y/:/$"\n"/ file

Rails 4 - passing variable to partial

From the Rails api on PartialRender:

Rendering the default case

If you're not going to be using any of the options like collections or layouts, you can also use the short-hand defaults of render to render partials.

Examples:

# Instead of <%= render partial: "account" %>
<%= render "account" %>

# Instead of <%= render partial: "account", locals: { account: @buyer } %>
<%= render "account", account: @buyer %>

# @account.to_partial_path returns 'accounts/account', so it can be used to replace:
# <%= render partial: "accounts/account", locals: { account: @account} %>
<%= render @account %>

# @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
# that's why we can replace:
# <%= render partial: "posts/post", collection: @posts %>
<%= render @posts %>

So, you can use pass a local variable size to render as follows:

<%= render @users, size: 50 %>

and then use it in the _user.html.erb partial:

<li>
    <%= gravatar_for user, size: size %>
    <%= link_to user.name, user %>
</li>

Note that size: size is equivalent to :size => size.

How to escape strings in SQL Server using PHP?

You could look into the PDO Library. You can use prepared statements with PDO, which will automatically escape any bad characters in your strings if you do the prepared statements correctly. This is for PHP 5 only I think.

Change onclick action with a Javascript function

var Foo = function(){
    document.getElementById( "a" ).setAttribute( "onClick", "javascript: Boo();" );
}

var Boo = function(){
    alert("test");
}

Offset a background image from the right using CSS

A simple but dirty trick is to simply add the offset you want to the image you are using as background. it's not maintainable, but it gets the job done.

How to install the Raspberry Pi cross compiler on my Linux host machine?

The initial question has been posted quite some time ago and in the meantime Debian has made huge headway in the area of multiarch support.

Multiarch is a great achievement for cross compilation!

In a nutshell the following steps are required to leverage multiarch for Raspbian Jessie cross compilation:

  • On your Ubuntu host install Debian Jessie amd64 within a chroot or a LXC container.
  • Enable the foreign architecture armhf.
  • Install the cross compiler from the emdebian tools repository.
  • Tweak the cross compiler (it would generate code for ARMv7-A by default) by writing a custom gcc specs file.
  • Install armhf libraries (libstdc++ etc.) from the Raspbian repository.
  • Build your source code.

Since this is a lot of work I have automated the above setup. You can read about it here:

Cross Compiling for Raspbian

Creating dummy variables in pandas for python

For my case, dmatrices in patsy solved my problem. Actually, this function is designed for the generation of dependent and independent variables from a given DataFrame with an R-style formula string. But it can be used for the generation of dummy features from the categorical features. All you need to do would be drop the column 'Intercept' that is generated by dmatrices automatically regardless of your original DataFrame.

import pandas as pd
from patsy import dmatrices

df_original = pd.DataFrame({
   'A': ['red', 'green', 'red', 'green'],
   'B': ['car', 'car', 'truck', 'truck'],
   'C': [10,11,12,13],
   'D': ['alice', 'bob', 'charlie', 'alice']},
   index=[0, 1, 2, 3])

_, df_dummyfied = dmatrices('A ~ A + B + C + D', data=df_original, return_type='dataframe')
df_dummyfied = df_dummyfied.drop('Intercept', axis=1)

df_dummyfied.columns    
Index([u'A[T.red]', u'B[T.truck]', u'D[T.bob]', u'D[T.charlie]', u'C'], dtype='object')

df_dummyfied
   A[T.red]  B[T.truck]  D[T.bob]  D[T.charlie]     C
0       1.0         0.0       0.0           0.0  10.0
1       0.0         0.0       1.0           0.0  11.0
2       1.0         1.0       0.0           1.0  12.0
3       0.0         1.0       0.0           0.0  13.0

Alter MySQL table to add comments on columns

As per the documentation you can add comments only at the time of creating table. So it is must to have table definition. One way to automate it using the script to read the definition and update your comments.

Reference:

http://cornempire.net/2010/04/15/add-comments-to-column-mysql/

http://bugs.mysql.com/bug.php?id=64439

403 Forbidden vs 401 Unauthorized HTTP responses

TL;DR

  • 401: A refusal that has to do with authentication
  • 403: A refusal that has NOTHING to do with authentication

Practical Examples

If apache requires authentication (via .htaccess), and you hit Cancel, it will respond with a 401 Authorization Required

If nginx finds a file, but has no access rights (user/group) to read/access it, it will respond with 403 Forbidden

RFC (2616 Section 10)

401 Unauthorized (10.4.2)

Meaning 1: Need to authenticate

The request requires user authentication. ...

Meaning 2: Authentication insufficient

... If the request already included Authorization credentials, then the 401 response indicates that authorization has been refused for those credentials. ...

403 Forbidden (10.4.4)

Meaning: Unrelated to authentication

... Authorization will not help ...

More details:

  • The server understood the request, but is refusing to fulfill it.

  • It SHOULD describe the reason for the refusal in the entity

  • The status code 404 (Not Found) can be used instead

    (If the server wants to keep this information from client)

Java, return if trimmed String in List contains String

String search = "A";
for(String s : myList)
    if(s.contains(search)) return true;
return false;

This will iterate over each string in the list, and check if it contains the string you're looking for. If it's only spaces you want to trap for, you can do this:

String search = "A";
for(String s : myList)
    if(s.replaceAll(" ","").contains(search)) return true;
return false;

which will first replace spaces with empty strings before searching. Additionally, if you just want to trim the string first, you can do:

String search = "A";
for(String s : myList)
    if(s.trim().contains(search)) return true;
return false;

Reading data from XML

Try GetElementsByTagName method of XMLDocument class to read specific data or LoadXml method to read all data to xml document.

MySQL Error: #1142 - SELECT command denied to user

You need to grant SELECT permissions to the MySQL user who is connecting to MySQL

same question as here Error: select command denied to user '<userid>'@'<ip-address>' for table '<table-name>'

see answers of the link ;)

"Failed to load platform plugin "xcb" " while launching qt5 app on linux without qt installed

I had this problem, and on a hunch I removed the Qt Configs from my environment. I.e.,

rm -rf ~/.config/Qt*

Then I started qtcreator and it reconfigured itself with the existing state of the machine. It no longer remembered where my projects were, but that just meant I had to browse to them "for the first time" again.

But more importantly it built itself a coherent set of library paths, so I could rebuild and run my project executables again without the xcb or qxcb libraries going missing.

How to run different python versions in cmd

I also met the case to use both python2 and python3 on my Windows machine. Here's how i resolved it:

  1. download python2x and python3x, installed them.
  2. add C:\Python35;C:\Python35\Scripts;C:\Python27;C:\Python27\Scripts to environment variable PATH.
  3. Go to C:\Python35 to rename python.exe to python3.exe, also to C:\Python27, rename python.exe to python2.exe.
  4. restart your command window.
  5. type python2 scriptname.py, or python3 scriptname.py in command line to switch the version you like.