Programs & Examples On #Recordstore

class in Java ME MIDP API - javax.microedition.rms.RecordStore

How to Use slideDown (or show) function on a table row?

I did use the ideas provided here and faced some problems. I fixed them all and have a smooth one-liner I'd like to share.

$('#row_to_slideup').find('> td').css({'height':'0px'}).wrapInner('<div style=\"display:block;\" />').parent().find('td > div').slideUp('slow', function() {$(this).parent().parent().remove();});

It uses css on the td element. It reduces the height to 0px. That way only the height of the content of the newly created div-wrapper inside of each td element matters.

The slideUp is on slow. If you make it even slower you might realize some glitch. A small jump at the beginning. This is because of the mentioned css setting. But without those settings the row would not decrease in height. Only its content would.

At the end the tr element gets removed.

The whole line only contains JQuery and no native Javascript.

Hope it helps.

Here is an example code:

    <html>
            <head>
                    <script src="https://code.jquery.com/jquery-3.2.0.min.js">               </script>
            </head>
            <body>
                    <table>
                            <thead>
                                    <tr>
                                            <th>header_column 1</th>
                                            <th>header column 2</th>
                                    </tr>
                            </thead>
                            <tbody>
                                    <tr id="row1"><td>row 1 left</td><td>row 1 right</td></tr>
                                    <tr id="row2"><td>row 2 left</td><td>row 2 right</td></tr>
                                    <tr id="row3"><td>row 3 left</td><td>row 3 right</td></tr>
                                    <tr id="row4"><td>row 4 left</td><td>row 4 right</td></tr>
                            </tbody>
                    </table>
                    <script>
    setTimeout(function() {
    $('#row2').find('> td').css({'height':'0px'}).wrapInner('<div style=\"display:block;\" />').parent().find('td > div').slideUp('slow',         function() {$(this).parent().parent().remove();});
    }, 2000);
                    </script>
            </body>
    </html>

When is a CDATA section necessary within a script tag?

When you are going for strict XHTML compliance, you need the CDATA so less than and ampersands are not flagged as invalid characters.

How can I access an internal class from an external assembly?

I see only one case that you would allow exposure to your internal members to another assembly and that is for testing purposes.

Saying that there is a way to allow "Friend" assemblies access to internals:

In the AssemblyInfo.cs file of the project you add a line for each assembly.

[assembly: InternalsVisibleTo("name of assembly here")]

this info is available here.

Hope this helps.

C# - insert values from file into two arrays

var Text = File.ReadAllLines("Path"); foreach (var i in Text) {    var SplitText = i.Split().Where(x=> x.Lenght>1).ToList();    //@Array1 add SplitText[0]    //@Array2 add SpliteText[1]   }  

What's the difference between ASCII and Unicode?

ASCII has 128 code positions, allocated to graphic characters and control characters (control codes).

Unicode has 1,114,112 code positions. About 100,000 of them have currently been allocated to characters, and many code points have been made permanently noncharacters (i.e. not used to encode any character ever), and most code points are not yet assigned.

The only things that ASCII and Unicode have in common are: 1) They are character codes. 2) The 128 first code positions of Unicode have been defined to have the same meanings as in ASCII, except that the code positions of ASCII control characters are just defined as denoting control characters, with names corresponding to their ASCII names, but their meanings are not defined in Unicode.

Sometimes, however, Unicode is characterized (even in the Unicode standard!) as “wide ASCII”. This is a slogan that mainly tries to convey the idea that Unicode is meant to be a universal character code the same way as ASCII once was (though the character repertoire of ASCII was hopelessly insufficient for universal use), as opposite to using different codes in different systems and applications and for different languages.

Unicode as such defines only the “logical size” of characters: Each character has a code number in a specific range. These code numbers can be presented using different transfer encodings, and internally, in memory, Unicode characters are usually represented using one or two 16-bit quantities per character, depending on character range, sometimes using one 32-bit quantity per character.

JQuery find first parent element with specific class prefix

Jquery later allowed you to to find the parents with the .parents() method.

Hence I recommend using:

var $div = $('#divid').parents('div[class^="div-a"]');

This gives all parent nodes matching the selector. To get the first parent matching the selector use:

var $div = $('#divid').parents('div[class^="div-a"]').eq(0);

For other such DOM traversal queries, check out the documentation on traversing the DOM.

Docker error response from daemon: "Conflict ... already in use by container"

I got this error quite a lot, so now I do a batch removal of all unused containers at once:

docker container prune 

add -f to force removal without prompt.

To list all unused containers (without removal):

docker container ls -a --filter status=exited --filter status=created 

See here more examples how to prune other objects (networks, volumes, etc.).

How does Task<int> become an int?

Does an implicit conversion occur between Task<> and int?

Nope. This is just part of how async/await works.

Any method declared as async has to have a return type of:

  • void (avoid if possible)
  • Task (no result beyond notification of completion/failure)
  • Task<T> (for a logical result of type T in an async manner)

The compiler does all the appropriate wrapping. The point is that you're asynchronously returning urlContents.Length - you can't make the method just return int, as the actual method will return when it hits the first await expression which hasn't already completed. So instead, it returns a Task<int> which will complete when the async method itself completes.

Note that await does the opposite - it unwraps a Task<T> to a T value, which is how this line works:

string urlContents = await getStringTask;

... but of course it unwraps it asynchronously, whereas just using Result would block until the task had completed. (await can unwrap other types which implement the awaitable pattern, but Task<T> is the one you're likely to use most often.)

This dual wrapping/unwrapping is what allows async to be so composable. For example, I could write another async method which calls yours and doubles the result:

public async Task<int> AccessTheWebAndDoubleAsync()
{
    var task = AccessTheWebAsync();
    int result = await task;
    return result * 2;
}

(Or simply return await AccessTheWebAsync() * 2; of course.)

How do I programmatically click on an element in JavaScript?

Are you trying to actually follow the link or trigger the onclick? You can trigger an onclick with something like this:

var link = document.getElementById(linkId);
link.onclick.call(link);

How do you move a file?

May also be called, "rename" by tortoise, but svn move, is the command in the barebones svn client.

Browser can't access/find relative resources like CSS, images and links when calling a Servlet which forwards to a JSP

You can try out this one as well as. Because this worked for me and it's simple.

<style>
    <%@ include file="/css/style.css" %>
</style>

The proxy server received an invalid response from an upstream server

This is not mentioned in you post but I suspect you are initiating an SSL connection from the browser to Apache, where VirtualHosts are configured, and Apache does a revese proxy to your Tomcat.

There is a serious bug in (some versions ?) of IE that sends the 'wrong' host information in an SSL connection (see EDIT below) and confuses the Apache VirtualHosts. In short the server name presented is the one of the reverse DNS resolution of the IP, not the one in the URL.

The workaround is to have one IP address per SSL virtual hosts/server name. Is short, you must end up with something like

1 server name == 1 IP address == 1 certificate == 1 Apache Virtual Host

EDIT

Though the conclusion is correct, the identification of the problem is better described here http://en.wikipedia.org/wiki/Server_Name_Indication

foreach vs someList.ForEach(){}

The second way you showed uses an extension method to execute the delegate method for each of the elements in the list.

This way, you have another delegate (=method) call.

Additionally, there is the possibility to iterate the list with a for loop.

How can I add a vertical scrollbar to my div automatically?

I'm not quite sure what you're attempting to use the div for, but this is an example with some random text.

Mr_Green gave the correct instructions when he said to add overflow-y: auto as that restricts it to vertical scrolling. This is a JSFiddle example:

JSFiddle

Remove style attribute from HTML tags

The pragmatic regex (<[^>]+) style=".*?" will solve this problem in all reasonable cases. The part of the match that is not the first captured group should be removed, like this:

$output = preg_replace('/(<[^>]+) style=".*?"/i', '$1', $input);

Match a < followed by one or more "not >" until we come to space and the style="..." part. The /i makes it work even with STYLE="...". Replace this match with $1, which is the captured group. It will leave the tag as is, if the tag doesn't include style="...".

How to display a gif fullscreen for a webpage background?

if you're happy using it as a background image and CSS3 then background-size: cover; would do the trick

How can I show the table structure in SQL Server query?

To print a schema, I use jade and do an export to a file of the database then bring it into word to format and print

What is the shortest function for reading a cookie by name in JavaScript?

Using cwolves' answer, but not using a closure nor a pre-computed hash :

// Golfed it a bit, too...
function readCookie(n){
  var c = document.cookie.split('; '),
      i = c.length,
      C;

  for(; i>0; i--){
     C = c[i].split('=');
     if(C[0] == n) return C[1];
  }
}

...and minifying...

function readCookie(n){var c=document.cookie.split('; '),i=c.length,C;for(;i>0;i--){C=c[i].split('=');if(C[0]==n)return C[1];}}

...equals 127 bytes.

Difference of keywords 'typename' and 'class' in templates?

typename and class are interchangeable in the basic case of specifying a template:

template<class T>
class Foo
{
};

and

template<typename T>
class Foo
{
};

are equivalent.

Having said that, there are specific cases where there is a difference between typename and class.

The first one is in the case of dependent types. typename is used to declare when you are referencing a nested type that depends on another template parameter, such as the typedef in this example:

template<typename param_t>
class Foo
{
    typedef typename param_t::baz sub_t;
};

The second one you actually show in your question, though you might not realize it:

template < template < typename, typename > class Container, typename Type >

When specifying a template template, the class keyword MUST be used as above -- it is not interchangeable with typename in this case (note: since C++17 both keywords are allowed in this case).

You also must use class when explicitly instantiating a template:

template class Foo<int>;

I'm sure that there are other cases that I've missed, but the bottom line is: these two keywords are not equivalent, and these are some common cases where you need to use one or the other.

tqdm in Jupyter Notebook prints new progress bars repeatedly

Most of the answers are outdated now. Better if you import tqdm correctly.

from tqdm import tqdm_notebook as tqdm

enter image description here

Compare 2 JSON objects

Simply parsing the JSON and comparing the two objects is not enough because it wouldn't be the exact same object references (but might be the same values).

You need to do a deep equals.

From http://threebit.net/mail-archive/rails-spinoffs/msg06156.html - which seems the use jQuery.

Object.extend(Object, {
   deepEquals: function(o1, o2) {
     var k1 = Object.keys(o1).sort();
     var k2 = Object.keys(o2).sort();
     if (k1.length != k2.length) return false;
     return k1.zip(k2, function(keyPair) {
       if(typeof o1[keyPair[0]] == typeof o2[keyPair[1]] == "object"){
         return deepEquals(o1[keyPair[0]], o2[keyPair[1]])
       } else {
         return o1[keyPair[0]] == o2[keyPair[1]];
       }
     }).all();
   }
});

Usage:

var anObj = JSON.parse(jsonString1);
var anotherObj= JSON.parse(jsonString2);

if (Object.deepEquals(anObj, anotherObj))
   ...

Convert a float64 to an int in Go

If its simply from float64 to int, this should work

package main

import (
    "fmt"
)

func main() {
    nf := []float64{-1.9999, -2.0001, -2.0, 0, 1.9999, 2.0001, 2.0}

    //round
    fmt.Printf("Round : ")
    for _, f := range nf {
        fmt.Printf("%d ", round(f))
    }
    fmt.Printf("\n")

    //rounddown ie. math.floor
    fmt.Printf("RoundD: ")
    for _, f := range nf {
        fmt.Printf("%d ", roundD(f))
    }
    fmt.Printf("\n")

    //roundup ie. math.ceil
    fmt.Printf("RoundU: ")
    for _, f := range nf {
        fmt.Printf("%d ", roundU(f)) 
    }
    fmt.Printf("\n")

}

func roundU(val float64) int {
    if val > 0 { return int(val+1.0) }
    return int(val)
}

func roundD(val float64) int {
    if val < 0 { return int(val-1.0) }
    return int(val)
}

func round(val float64) int {
    if val < 0 { return int(val-0.5) }
    return int(val+0.5)
}

Outputs:

Round : -2 -2 -2 0 2 2 2 
RoundD: -2 -3 -3 0 1 2 2 
RoundU: -1 -2 -2 0 2 3 3 

Here's the code in the playground - https://play.golang.org/p/HmFfM6Grqh

Forking / Multi-Threaded Processes | Bash

I don't like using wait because it gets blocked until the process exits, which is not ideal when there are multiple process to wait on as I can't get a status update until the current process is done. I prefer to use a combination of kill -0 and sleep to this.

Given an array of pids to wait on, I use the below waitPids() function to get a continuous feedback on what pids are still pending to finish.

declare -a pids
waitPids() {
    while [ ${#pids[@]} -ne 0 ]; do
        echo "Waiting for pids: ${pids[@]}"
        local range=$(eval echo {0..$((${#pids[@]}-1))})
        local i
        for i in $range; do
            if ! kill -0 ${pids[$i]} 2> /dev/null; then
                echo "Done -- ${pids[$i]}"
                unset pids[$i]
            fi
        done
        pids=("${pids[@]}") # Expunge nulls created by unset.
        sleep 1
    done
    echo "Done!"
}

When I start a process in the background, I add its pid immediately to the pids array by using this below utility function:

addPid() {
    local desc=$1
    local pid=$2
    echo "$desc -- $pid"
    pids=(${pids[@]} $pid)
}

Here is a sample that shows how to use:

for i in {2..5}; do
    sleep $i &
    addPid "Sleep for $i" $!
done
waitPids

And here is how the feedback looks:

Sleep for 2 -- 36271
Sleep for 3 -- 36272
Sleep for 4 -- 36273
Sleep for 5 -- 36274
Waiting for pids: 36271 36272 36273 36274
Waiting for pids: 36271 36272 36273 36274
Waiting for pids: 36271 36272 36273 36274
Done -- 36271
Waiting for pids: 36272 36273 36274
Done -- 36272
Waiting for pids: 36273 36274
Done -- 36273
Waiting for pids: 36274
Done -- 36274
Done!

JavaScript closures vs. anonymous functions

I've never been happy with the way anybody explains this.

The key to understanding closures is to understand what JS would be like without closures.

Without closures, this would throw an error

function outerFunc(){
    var outerVar = 'an outerFunc var';
    return function(){
        alert(outerVar);
    }
}

outerFunc()(); //returns inner function and fires it

Once outerFunc has returned in an imaginary closure-disabled version of JavaScript, the reference to outerVar would be garbage collected and gone leaving nothing there for the inner func to reference.

Closures are essentially the special rules that kick in and make it possible for those vars to exist when an inner function references an outer function's variables. With closures the vars referenced are maintained even after the outer function is done or 'closed' if that helps you remember the point.

Even with closures, the life cycle of local vars in a function with no inner funcs that reference its locals works the same as it would in a closure-less version. When the function is finished, the locals get garbage collected.

Once you have a reference in an inner func to an outer var, however it's like a doorjamb gets put in the way of garbage collection for those referenced vars.

A perhaps more accurate way to look at closures, is that the inner function basically uses the inner scope as its own scope foudnation.

But the context referenced is in fact, persistent, not like a snapshot. Repeatedly firing a returned inner function that keeps incrementing and logging an outer function's local var will keep alerting higher values.

function outerFunc(){
    var incrementMe = 0;
    return function(){ incrementMe++; console.log(incrementMe); }
}
var inc = outerFunc();
inc(); //logs 1
inc(); //logs 2

How to change the docker image installation directory?

In CentOS 6.5

service docker stop
mkdir /data/docker  (new directory)
vi /etc/sysconfig/docker

add following line

other_args=" -g /data/docker -p /var/run/docker.pid"

then save the file and start docker again

service docker start

and will make repository file in /data/docker

How do I use the conditional operator (? :) in Ruby?

Your use of ERB suggests that you are in Rails. If so, then consider truncate, a built-in helper which will do the job for you:

<% question = truncate(question, :length=>30) %>

Create folder in Android

If you are trying to make more than just one folder on the root of the sdcard, ex. Environment.getExternalStorageDirectory() + "/Example/Ex App/"

then instead of folder.mkdir() you would use folder.mkdirs()

I've made this mistake in the past & I took forever to figure it out.

How to resolve "Waiting for Debugger" message?

I get this if I switch the usb cable to a difference port on my PC, odd but it works when I switch it back again. Also I think I've got this when there's been another device or emulator running at the same time, or two instances of Eclipse open.

How are VST Plugins made?

I wrote up a HOWTO for VST development on C++ with Visual Studio awhile back which details the steps necessary to create a basic plugin for the Windows platform (the Mac version of this article is forthcoming). On Windows, a VST plugin is just a normal DLL, but there are a number of "gotchas", and you need to build the plugin using some specific compiler/linker switches or else it won't be recognized by some hosts.

As for the Mac, a VST plugin is just a bundle with the .vst extension, though there are also a few settings which must be configured correctly in order to generate a valid plugin. You can also download a set of Xcode VST plugin project templates I made awhile back which can help you to write a working plugin on that platform.

As for AudioUnits, Apple has provided their own project templates which are included with Xcode. Apple also has very good tutorials and documentation online:

I would also highly recommend checking out the Juce Framework, which has excellent support for creating cross-platform VST/AU plugins. If you're going open-source, then Juce is a no-brainer, but you will need to pay licensing fees for it if you plan on releasing your work without source code.

Moving uncommitted changes to a new branch

Just create a new branch with git checkout -b ABC_1; your uncommitted changes will be kept, and you then commit them to that branch.

How to upgrade docker-compose to latest version

use this from command line: sudo curl -L "https://github.com/docker/compose/releases/download/1.22.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

Write down the latest release version

Apply executable permissions to the binary:

sudo chmod +x /usr/local/bin/docker-compose

Then test version:

$ docker-compose --version

How to install Python packages from the tar.gz file without using pip install

Is it possible for you to use sudo apt-get install python-seaborn instead? Basically tar.gz is just a zip file containing a setup, so what you want to do is to unzip it, cd to the place where it is downloaded and use gunzip -c seaborn-0.7.0.tar.gz | tar xf - for linux. Change dictionary into the new seaborn unzipped file and execute python setup.py install

Difference between RegisterStartupScript and RegisterClientScriptBlock?

Here's a simplest example from ASP.NET Community, this gave me a clear understanding on the concept....

what difference does this make?

For an example of this, here is a way to put focus on a text box on a page when the page is loaded into the browser—with Visual Basic using the RegisterStartupScript method:

Page.ClientScript.RegisterStartupScript(Me.GetType(), "Testing", _ 
"document.forms[0]['TextBox1'].focus();", True)

This works well because the textbox on the page is generated and placed on the page by the time the browser gets down to the bottom of the page and gets to this little bit of JavaScript.

But, if instead it was written like this (using the RegisterClientScriptBlock method):

Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), "Testing", _
"document.forms[0]['TextBox1'].focus();", True)

Focus will not get to the textbox control and a JavaScript error will be generated on the page

The reason for this is that the browser will encounter the JavaScript before the text box is on the page. Therefore, the JavaScript will not be able to find a TextBox1.

What does API level mean?

An API is ready-made source code library.

In Java for example APIs are a set of related classes and interfaces that come in packages. This picture illustrates the libraries included in the Java Standard Edition API. Packages are denoted by their color.

This pictures illustrates the libraries included in the Java Standard Edition API

typecast string to integer - Postgres

you can use this query

SUM(NULLIF(conversion_units, '')::numeric)

How to uncheck a radio button?

Thanks Patrick, you made my day! It's mousedown you have to use. However I've improved the code so you can handle a group of radio buttons.

//We need to bind click handler as well
//as FF sets button checked after mousedown, but before click
$('input:radio').bind('click mousedown', (function() {
    //Capture radio button status within its handler scope,
    //so we do not use any global vars and every radio button keeps its own status.
    //This required to uncheck them later.
    //We need to store status separately as browser updates checked status before click handler called,
    //so radio button will always be checked.
    var isChecked;

    return function(event) {
        //console.log(event.type + ": " + this.checked);

        if(event.type == 'click') {
            //console.log(isChecked);

            if(isChecked) {
                //Uncheck and update status
                isChecked = this.checked = false;
            } else {
                //Update status
                //Browser will check the button by itself
                isChecked = true;

                //Do something else if radio button selected
                /*
                if(this.value == 'somevalue') {
                    doSomething();
                } else {
                    doSomethingElse();
                }
                */
            }
    } else {
        //Get the right status before browser sets it
        //We need to use onmousedown event here, as it is the only cross-browser compatible event for radio buttons
        isChecked = this.checked;
    }
}})());

How to do what head, tail, more, less, sed do in Powershell?

Here are the built-in ways to do head and tail. Don't use pipes because if you have a large file, it will be extremely slow. Using these built-in options will be extremely fast even for huge files.

gc log.txt -head 10 
gc log.txt -tail 10
gc log.txt -tail 10 -wait # equivalent to tail -f

How can I convert my Java program to an .exe file?

Alternatively, you can use some java-to-c translator (e.g., JCGO) and compile the generated C files to a native binary (.exe) file for the target platform.

How do I mock a static method that returns void with PowerMock?

In simpler terms, Imagine if you want mock below line:

StaticClass.method();

then you write below lines of code to mock:

PowerMockito.mockStatic(StaticClass.class);
PowerMockito.doNothing().when(StaticClass.class);
StaticClass.method();

How to choose multiple files using File Upload Control?

default.aspx code

<asp:FileUpload runat="server" id="fileUpload1" Multiple="Multiple">
        </asp:FileUpload>
<asp:Button runat="server" Text="Upload Files" id="uploadBtn"/>

default.aspx.vb

Protected Sub uploadBtn_Click(sender As Object, e As System.EventArgs) Handles uploadBtn.Click
    Dim ImageFiles As HttpFileCollection = Request.Files
    For i As Integer = 0 To ImageFiles.Count - 1
    Dim file As HttpPostedFile = ImageFiles(i)
        file.SaveAs(Server.MapPath("Uploads/") & file.FileName) 
    Next       
End Sub

@Autowired and static method

What you can do is @Autowired a setter method and have it set a new static field.

public class Boo {
    @Autowired
    Foo foo;

    static Foo staticFoo;   

    @Autowired
    public void setStaticFoo(Foo foo) {
        Boo.staticFoo = foo;
    }

    public static void randomMethod() {
         staticFoo.doStuff();
    }
}

When the bean gets processed, Spring will inject a Foo implementation instance into the instance field foo. It will then also inject the same Foo instance into the setStaticFoo() argument list, which will be used to set the static field.

This is a terrible workaround and will fail if you try to use randomMethod() before Spring has processed an instance of Boo.

How do I create sql query for searching partial matches?

This may work as well.

SELECT * 
FROM myTable
WHERE CHARINDEX('mall', name) > 0
  OR CHARINDEX('mall', description) > 0

Maven skip tests

I have another approach for Intellij users, and it is working very fine for me:

  1. Click on the "Skip Test" button

enter image description here

  1. Hold the "CTRL" button
  2. Select "clean" and "install"

enter image description here

  1. Click on the "Run" button in the maven pannel

enter image description here

How to sort an array in Bash

If you can compute a unique integer for each element in the array, like this:

tab='0123456789abcdefghijklmnopqrstuvwxyz'

# build the reversed ordinal map
for ((i = 0; i < ${#tab}; i++)); do
    declare -g ord_${tab:i:1}=$i
done

function sexy_int() {
    local sum=0
    local i ch ref
    for ((i = 0; i < ${#1}; i++)); do
        ch="${1:i:1}"
        ref="ord_$ch"
        (( sum += ${!ref} ))
    done
    return $sum
}

sexy_int hello
echo "hello -> $?"
sexy_int world
echo "world -> $?"

then, you can use these integers as array indexes, because Bash always use sparse array, so no need to worry about unused indexes:

array=(a c b f 3 5)
for el in "${array[@]}"; do
    sexy_int "$el"
    sorted[$?]="$el"
done

echo "${sorted[@]}"
  • Pros. Fast.
  • Cons. Duplicated elements are merged, and it can be impossible to map contents to 32-bit unique integers.

How to use Scanner to accept only valid int as input

  1. the condition num2 < num1 should be num2 <= num1 if num2 has to be greater than num1
  2. not knowing what the kb object is, I'd read a String and then trying Integer.parseInt() and if you don't catch an exception then it's a number, if you do, read a new one, maybe by setting num2 to Integer.MIN_VALUE and using the same type of logic in your example.

Why I get 411 Length required error?

Change the way you requested the method from POST to GET ..

SQL Server add auto increment primary key to existing table

Try something like this (on a test table first):

USE your_database_name
GO
WHILE (SELECT COUNT(*) FROM your_table WHERE your_id_field IS NULL) > 0
BEGIN
    SET ROWCOUNT 1
    UPDATE your_table SET your_id_field = MAX(your_id_field)+1
END
PRINT 'ALL DONE'

I have not tested this at all, so be careful!

PHP Error: Function name must be a string

A useful explanation to how braces are used (in addition to Filip Ekberg's useful answer, above) can be found in the short paper Parenthesis in Programming Languages.

jQuery UI Dialog with ASP.NET button postback

I just added the following line after you created the dialog:

$(".ui-dialog").prependTo("form");

How to add a recyclerView inside another recyclerView

I would like to suggest to use a single RecyclerView and populate your list items dynamically. I've added a github project to describe how this can be done. You might have a look. While the other solutions will work just fine, I would like to suggest, this is a much faster and efficient way of showing multiple lists in a RecyclerView.

The idea is to add logic in your onCreateViewHolder and onBindViewHolder method so that you can inflate proper view for the exact positions in your RecyclerView.

I've added a sample project along with that wiki too. You might clone and check what it does. For convenience, I am posting the adapter that I have used.

public class DynamicListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private static final int FOOTER_VIEW = 1;
    private static final int FIRST_LIST_ITEM_VIEW = 2;
    private static final int FIRST_LIST_HEADER_VIEW = 3;
    private static final int SECOND_LIST_ITEM_VIEW = 4;
    private static final int SECOND_LIST_HEADER_VIEW = 5;

    private ArrayList<ListObject> firstList = new ArrayList<ListObject>();
    private ArrayList<ListObject> secondList = new ArrayList<ListObject>();

    public DynamicListAdapter() {
    }

    public void setFirstList(ArrayList<ListObject> firstList) {
        this.firstList = firstList;
    }

    public void setSecondList(ArrayList<ListObject> secondList) {
        this.secondList = secondList;
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        // List items of first list
        private TextView mTextDescription1;
        private TextView mListItemTitle1;

        // List items of second list
        private TextView mTextDescription2;
        private TextView mListItemTitle2;

        // Element of footer view
        private TextView footerTextView;

        public ViewHolder(final View itemView) {
            super(itemView);

            // Get the view of the elements of first list
            mTextDescription1 = (TextView) itemView.findViewById(R.id.description1);
            mListItemTitle1 = (TextView) itemView.findViewById(R.id.title1);

            // Get the view of the elements of second list
            mTextDescription2 = (TextView) itemView.findViewById(R.id.description2);
            mListItemTitle2 = (TextView) itemView.findViewById(R.id.title2);

            // Get the view of the footer elements
            footerTextView = (TextView) itemView.findViewById(R.id.footer);
        }

        public void bindViewSecondList(int pos) {

            if (firstList == null) pos = pos - 1;
            else {
                if (firstList.size() == 0) pos = pos - 1;
                else pos = pos - firstList.size() - 2;
            }

            final String description = secondList.get(pos).getDescription();
            final String title = secondList.get(pos).getTitle();

            mTextDescription2.setText(description);
            mListItemTitle2.setText(title);
        }

        public void bindViewFirstList(int pos) {

            // Decrease pos by 1 as there is a header view now.
            pos = pos - 1;

            final String description = firstList.get(pos).getDescription();
            final String title = firstList.get(pos).getTitle();

            mTextDescription1.setText(description);
            mListItemTitle1.setText(title);
        }

        public void bindViewFooter(int pos) {
            footerTextView.setText("This is footer");
        }
    }

    public class FooterViewHolder extends ViewHolder {
        public FooterViewHolder(View itemView) {
            super(itemView);
        }
    }

    private class FirstListHeaderViewHolder extends ViewHolder {
        public FirstListHeaderViewHolder(View itemView) {
            super(itemView);
        }
    }

    private class FirstListItemViewHolder extends ViewHolder {
        public FirstListItemViewHolder(View itemView) {
            super(itemView);
        }
    }

    private class SecondListHeaderViewHolder extends ViewHolder {
        public SecondListHeaderViewHolder(View itemView) {
            super(itemView);
        }
    }

    private class SecondListItemViewHolder extends ViewHolder {
        public SecondListItemViewHolder(View itemView) {
            super(itemView);
        }
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View v;

        if (viewType == FOOTER_VIEW) {
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_footer, parent, false);
            FooterViewHolder vh = new FooterViewHolder(v);
            return vh;

        } else if (viewType == FIRST_LIST_ITEM_VIEW) {
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_first_list, parent, false);
            FirstListItemViewHolder vh = new FirstListItemViewHolder(v);
            return vh;

        } else if (viewType == FIRST_LIST_HEADER_VIEW) {
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_first_list_header, parent, false);
            FirstListHeaderViewHolder vh = new FirstListHeaderViewHolder(v);
            return vh;

        } else if (viewType == SECOND_LIST_HEADER_VIEW) {
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_second_list_header, parent, false);
            SecondListHeaderViewHolder vh = new SecondListHeaderViewHolder(v);
            return vh;

        } else {
            // SECOND_LIST_ITEM_VIEW
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_second_list, parent, false);
            SecondListItemViewHolder vh = new SecondListItemViewHolder(v);
            return vh;
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        try {
            if (holder instanceof SecondListItemViewHolder) {
                SecondListItemViewHolder vh = (SecondListItemViewHolder) holder;
                vh.bindViewSecondList(position);

            } else if (holder instanceof FirstListHeaderViewHolder) {
                FirstListHeaderViewHolder vh = (FirstListHeaderViewHolder) holder;

            } else if (holder instanceof FirstListItemViewHolder) {
                FirstListItemViewHolder vh = (FirstListItemViewHolder) holder;
                vh.bindViewFirstList(position);

            } else if (holder instanceof SecondListHeaderViewHolder) {
                SecondListHeaderViewHolder vh = (SecondListHeaderViewHolder) holder;

            } else if (holder instanceof FooterViewHolder) {
                FooterViewHolder vh = (FooterViewHolder) holder;
                vh.bindViewFooter(position);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public int getItemCount() {

        int firstListSize = 0;
        int secondListSize = 0;

        if (secondList == null && firstList == null) return 0;

        if (secondList != null)
            secondListSize = secondList.size();
        if (firstList != null)
            firstListSize = firstList.size();

        if (secondListSize > 0 && firstListSize > 0)
            return 1 + firstListSize + 1 + secondListSize + 1;   // first list header, first list size, second list header , second list size, footer
        else if (secondListSize > 0 && firstListSize == 0)
            return 1 + secondListSize + 1;                       // second list header, second list size, footer
        else if (secondListSize == 0 && firstListSize > 0)
            return 1 + firstListSize;                            // first list header , first list size
        else return 0;
    }

    @Override
    public int getItemViewType(int position) {

        int firstListSize = 0;
        int secondListSize = 0;

        if (secondList == null && firstList == null)
            return super.getItemViewType(position);

        if (secondList != null)
            secondListSize = secondList.size();
        if (firstList != null)
            firstListSize = firstList.size();

        if (secondListSize > 0 && firstListSize > 0) {
            if (position == 0) return FIRST_LIST_HEADER_VIEW;
            else if (position == firstListSize + 1)
                return SECOND_LIST_HEADER_VIEW;
            else if (position == secondListSize + 1 + firstListSize + 1)
                return FOOTER_VIEW;
            else if (position > firstListSize + 1)
                return SECOND_LIST_ITEM_VIEW;
            else return FIRST_LIST_ITEM_VIEW;

        } else if (secondListSize > 0 && firstListSize == 0) {
            if (position == 0) return SECOND_LIST_HEADER_VIEW;
            else if (position == secondListSize + 1) return FOOTER_VIEW;
            else return SECOND_LIST_ITEM_VIEW;

        } else if (secondListSize == 0 && firstListSize > 0) {
            if (position == 0) return FIRST_LIST_HEADER_VIEW;
            else return FIRST_LIST_ITEM_VIEW;
        }

        return super.getItemViewType(position);
    }
}

There is another way of keeping your items in a single ArrayList of objects so that you can set an attribute tagging the items to indicate which item is from first list and which one belongs to second list. Then pass that ArrayList into your RecyclerView and then implement the logic inside adapter to populate them dynamically.

Hope that helps.

offsetTop vs. jQuery.offset().top

It is possible that the offset could be a non-integer, using em as the measurement unit, relative font-sizes in %.

I also theorise that the offset might not be a whole number when the zoom isn't 100% but that depends how the browser handles scaling.

What's the most useful and complete Java cheat sheet?

  1. I have personally found the dzone cheatsheet on core java to be really handy in the beginning. However the needs change as we grow and get used to things.

  2. There are a few listed (at the end of the post) in on this java learning resources article too

  3. For the most practical use, in recent past I have found Java API doc to be the best place to cheat code and learn new api. This helps specially when you want to focus on latest version of java.

  4. mkyong - is one my fav places to cheat a lot of code for quick start - http://www.mkyong.com/

  5. And last but not the least, Stackoverflow is king of all small handy code snippets. Just google a stuff you are trying and there is a chance that a page will be top of search results, most of my google search results end at stackoverflow. Many of the common questions are available here - https://stackoverflow.com/questions/tagged/java?sort=frequent

Can't update data-attribute value

Had a similar problem, I propose this solution althought is not supported in IE 10 and under.

Given

<div id='example' data-example-update='1'></div>

The Javascript standard defines a property called dataset to update data-example-update.

document.getElementById('example').dataset.exampleUpdate = 2;

Note: use camel case notation to access the correct data attribute.

Source: https://developer.mozilla.org/en-US/docs/Learn/HTML/Howto/Use_data_attributes

How do I display a wordpress page content?

@Sydney Try putting wp_reset_query() before you call the loop. This will display the content of your page.

<?php
    wp_reset_query(); // necessary to reset query
    while ( have_posts() ) : the_post();
        the_content();
    endwhile; // End of the loop.
?>

EDIT: Try this if you have some other loops that you previously ran. Place wp_reset_query(); where you find it most suitable, but before you call this loop.

How to check if a folder exists

Quite simple:

new File("/Path/To/File/or/Directory").exists();

And if you want to be certain it is a directory:

File f = new File("/Path/To/File/or/Directory");
if (f.exists() && f.isDirectory()) {
   ...
}

Access Https Rest Service using Spring RestTemplate

One point from me. I used a mutual cert authentication with spring-boot microservices. The following is working for me, key points here are keyManagerFactory.init(...) and sslcontext.init(keyManagerFactory.getKeyManagers(), null, new SecureRandom()) lines of code without them, at least for me, things did not work. Certificates are packaged by PKCS12.

@Value("${server.ssl.key-store-password}")
private String keyStorePassword;
@Value("${server.ssl.key-store-type}")
private String keyStoreType;
@Value("${server.ssl.key-store}")
private Resource resource;

private RestTemplate getRestTemplate() throws Exception {
    return new RestTemplate(clientHttpRequestFactory());
}

private ClientHttpRequestFactory clientHttpRequestFactory() throws Exception {
    return new HttpComponentsClientHttpRequestFactory(httpClient());
}

private HttpClient httpClient() throws Exception {

    KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("SunX509");
    KeyStore trustStore = KeyStore.getInstance(keyStoreType);

    if (resource.exists()) {
        InputStream inputStream = resource.getInputStream();

        try {
            if (inputStream != null) {
                trustStore.load(inputStream, keyStorePassword.toCharArray());
                keyManagerFactory.init(trustStore, keyStorePassword.toCharArray());
            }
        } finally {
            if (inputStream != null) {
                inputStream.close();
            }
        }
    } else {
        throw new RuntimeException("Cannot find resource: " + resource.getFilename());
    }

    SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore, new TrustSelfSignedStrategy()).build();
    sslcontext.init(keyManagerFactory.getKeyManagers(), null, new SecureRandom());
    SSLConnectionSocketFactory sslConnectionSocketFactory =
            new SSLConnectionSocketFactory(sslcontext, new String[]{"TLSv1.2"}, null, getDefaultHostnameVerifier());

    return HttpClients.custom().setSSLSocketFactory(sslConnectionSocketFactory).build();
}

What's the difference between emulation and simulation?

Both are models of an object that you have some means of controlling inputs and observing outputs. With an emulator, you want the output to be exactly what the object you are emulating would produce. With a simulator, you want certain properties of your output to be similar to what the object would produce.

Let me give an example -- suppose you want to do some system testing to see how adding a new sensor (like a thermometer) to a system would affect the system. You know that the thermometer sends a message 8 time a second containing its measurement.

Simulation -- if you do not have the thermometer yet, but you want to test that this message rate will not overload you system, you can simulate the sensor by attaching a unit that sends a random number 8 times a second. You can run any test that does not rely on the actual value the sensor sends.

Emulation -- suppose you have a very expensive thermometer that measures to 0.001 C, and you want to see if you can get by with a cheaper thermometer that only measures to the nearest 0.5 C. You can emulate the cheaper thermometer using an expensive thermometer by rounding the reading to the nearest 0.5 C and running tests that rely on the temperature values.

Passing data between controllers in Angular JS?

1

using $localStorage

app.controller('ProductController', function($scope, $localStorage) {
    $scope.setSelectedProduct = function(selectedObj){
        $localStorage.selectedObj= selectedObj;
    };
});

app.controller('CartController', function($scope,$localStorage) { 
    $scope.selectedProducts = $localStorage.selectedObj;
    $localStorage.$reset();//to remove
});

2

On click you can call method that invokes broadcast:

$rootScope.$broadcast('SOME_TAG', 'your value');

and the second controller will listen on this tag like:
$scope.$on('SOME_TAG', function(response) {
      // ....
})

3

using $rootScope:

4

window.sessionStorage.setItem("Mydata",data);
$scope.data = $window.sessionStorage.getItem("Mydata");

5

One way using angular service:

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

app.controller('one', function($scope, ser1){
$scope.inputText = ser1;
});

app.controller('two',function($scope, ser1){
$scope.inputTextTwo = ser1;
});

app.factory('ser1', function(){
return {o: ''};
});

Count the number of commits on a Git branch

You can use this command which uses awk on git bash/unix to get the number of commits.

    git shortlog -s -n | awk '/Author/ { print $1 }'

HTML if image is not found

If you want an alternative image instead of a text, you can as well use php:

$file="smiley.gif";
$alt_file="alt.gif";
if(file_exist($file)){
     echo "<img src='".$file."' border="0" />";
}else if($alt_file){
     // the alternative file too might not exist not exist
     echo "<img src='".$alt_file."' border="0" />";
}else{
  echo "smily face";
}

Node.js Error: Cannot find module express

Sometimes there are error while installing the node modules Try this:

  1. Delete node_modules
  2. npm install

How to do one-liner if else statement?

A very similar construction is available in the language

**if <statement>; <evaluation> {
   [statements ...]
} else {
   [statements ...]
}*

*

i.e.

if path,err := os.Executable(); err != nil {
   log.Println(err)
} else {
   log.Println(path)
}

Floating point exception( core dump

Floating Point Exception happens because of an unexpected infinity or NaN. You can track that using gdb, which allows you to see what is going on inside your C program while it runs. For more details: https://www.cs.swarthmore.edu/~newhall/unixhelp/howto_gdb.php

In a nutshell, these commands might be useful...

gcc -g myprog.c

gdb a.out

gdb core a.out

ddd a.out

Send data from javascript to a mysql database

You will have to submit this data to the server somehow. I'm assuming that you don't want to do a full page reload every time a user clicks a link, so you'll have to user XHR (AJAX). If you are not using jQuery (or some other JS library) you can read this tutorial on how to do the XHR request "by hand".

How to disable manual input for JQuery UI Datepicker field?

When you make the input, set it to be readonly.

<input type="text" name="datepicker" id="datepicker" readonly="readonly" />

How to chain scope queries with OR instead of AND?

An updated version of Rails/ActiveRecord may support this syntax natively. It would look similar to:

Foo.where(foo: 'bar').or.where(bar: 'bar')

As noted in this pull request https://github.com/rails/rails/pull/9052

For now, simply sticking with the following works great:

Foo.where('foo= ? OR bar= ?', 'bar', 'bar')

What's the purpose of SQL keyword "AS"?

It's a formal way of specifying a correlation name for an entity so that you can address it easily in another part of the query.

How to check the version of scipy

on command line

 example$:python
 >>> import scipy
 >>> scipy.__version__
 '0.9.0'

How do I convert uint to int in C#?

Given:

 uint n = 3;

int i = checked((int)n); //throws OverflowException if n > Int32.MaxValue
int i = unchecked((int)n); //converts the bits only 
                           //i will be negative if n > Int32.MaxValue

int i = (int)n; //same behavior as unchecked

or

int i = Convert.ToInt32(n); //same behavior as checked

--EDIT

Included info as mentioned by Kenan E. K.

How to center body on a page?

You have to specify the width to the body for it to center on the page.

Or put all the content in the div and center it.

<body>
    <div>
    jhfgdfjh
    </div>
</body>?

div {
    margin: 0px auto;
    width:400px;
}

?

How to create a showdown.js markdown extension

In your last block you have a comma after 'lang', followed immediately with a function. This is not valid json.

EDIT

It appears that the readme was incorrect. I had to to pass an array with the string 'twitter'.

var converter = new Showdown.converter({extensions: ['twitter']}); converter.makeHtml('whatever @meandave2020'); // output "<p>whatever <a href="http://twitter.com/meandave2020">@meandave2020</a></p>" 

I submitted a pull request to update this.

Get each line from textarea

You will want to look into the nl2br() function along with the trim().

The nl2br() will insert <br /> before the newline character (\n) and the trim() will remove any ending \n or whitespace characters.

$text = trim($_POST['textareaname']); // remove the last \n or whitespace character
$text = nl2br($text); // insert <br /> before \n 

That should do what you want.

UPDATE

The reason the following code will not work is because in order for \n to be recognized, it needs to be inside double quotes since double quotes parse data inside of them, where as single quotes takes it literally, IE "\n"

$text = str_replace('\n', '<br />', $text);

To fix it, it would be:

$text = str_replace("\n", '<br />', $text);

But it is still better to use the builtin nl2br() function, PHP provides.

EDIT

Sorry, I figured the first question was so you could add the linebreaks in, indeed this will change the answer quite a bit, as anytype of explode() will remove the line breaks, but here it is:

$text = trim($_POST['textareaname']);
$textAr = explode("\n", $text);
$textAr = array_filter($textAr, 'trim'); // remove any extra \r characters left behind

foreach ($textAr as $line) {
    // processing here. 
} 

If you do it this way, you will need to append the <br /> onto the end of the line before the processing is done on your own, as the explode() function will remove the \n characters.

Added the array_filter() to trim() off any extra \r characters that may have been lingering.

Comparing two files in linux terminal

You can use diff tool in linux to compare two files. You can use --changed-group-format and --unchanged-group-format options to filter required data.

Following three options can use to select the relevant group for each option:

  • '%<' get lines from FILE1

  • '%>' get lines from FILE2

  • '' (empty string) for removing lines from both files.

E.g: diff --changed-group-format="%<" --unchanged-group-format="" file1.txt file2.txt

[root@vmoracle11 tmp]# cat file1.txt 
test one
test two
test three
test four
test eight
[root@vmoracle11 tmp]# cat file2.txt 
test one
test three
test nine
[root@vmoracle11 tmp]# diff --changed-group-format='%<' --unchanged-group-format='' file1.txt file2.txt 
test two
test four
test eight

error: unknown type name ‘bool’

C99 does, if you have

#include <stdbool.h> 

If the compiler does not support C99, you can define it yourself:

// file : myboolean.h
#ifndef MYBOOLEAN_H
#define MYBOOLEAN_H

#define false 0
#define true 1
typedef int bool; // or #define bool int

#endif

(but note that this definition changes ABI for bool type so linking against external libraries which were compiled with properly defined bool may cause hard-to-diagnose runtime errors).

Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'

Use FromResult Method

public async Task<string> GetString()
{
   System.Threading.Thread.Sleep(5000);
   return await Task.FromResult("Hello");
}

Create a Date with a set timezone without using a string representation

One line solution

new Date(new Date(1422524805305).getTime() - 330*60*1000)

Instead of 1422524805305, use the timestamp in milliseconds Instead of 330, use your timezone offset in minutes wrt. GMT (eg India +5:30 is 5*60+30 = 330 minutes)

How to end a session in ExpressJS

Using req.session = null;, won't actually delete the session instance. The most proper solution would be req.session.destroy();, but this is essentially a wrapper for delete req.session;.

https://github.com/expressjs/session/blob/master/session/session.js

Session.prototype.destroy = function(fn){
  delete this.req.session;
  this.req.sessionStore.destroy(this.id, fn);
  return this;
};

How to center div vertically inside of absolutely positioned parent div

Use flex blox in your absoutely positioned div to center its content.

See example https://plnkr.co/edit/wJIX2NpbNhO34X68ZyoY?p=preview

.some-absolute-div {    
  display: -webkit-box;
  display: -webkit-flex;
  display: -moz-box;
  display: -moz-flex;
  display: -ms-flexbox;
  display: flex;

  -webkit-box-pack: center;
  -ms-flex-pack: center;
  -webkit-justify-content: center;
  -moz-justify-content: center;
  justify-content: center;

  -webkit-box-align: center;
  -ms-flex-align: center;
  -webkit-align-items: center;
  -moz-align-items: center;
  align-items: center;
}

Spring not autowiring in unit tests with JUnit

You need to use the Spring JUnit runner in order to wire in Spring beans from your context. The code below assumes that you have a application context called testContest.xml available on the test classpath.

import org.hibernate.SessionFactory;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

import java.sql.SQLException;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.startsWith;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath*:**/testContext.xml"})
@Transactional
public class someDaoTest {

    @Autowired
    protected SessionFactory sessionFactory;

    @Test
    public void testDBSourceIsCorrect() throws SQLException {
        String databaseProductName = sessionFactory.getCurrentSession()
                .connection()
                .getMetaData()
                .getDatabaseProductName();
        assertThat("Test container is pointing at the wrong DB.", databaseProductName, startsWith("HSQL"));
    }
}

Note: This works with Spring 2.5.2 and Hibernate 3.6.5

regular expression for anything but an empty string

You could also use:

public static bool IsWhiteSpace(string s) 
{
    return s.Trim().Length == 0;
}

Export to csv/excel from kibana

In Kibana 6.5, you can generate CSV under the Share Tab -> CSV Reports.

The request will be queued. Once the CSV is generated, it will be available for download under Management -> Reporting

How do you get the index of the current iteration of a foreach loop?

Better to use keyword continue safe construction like this

int i=-1;
foreach (Object o in collection)
{
    ++i;
    //...
    continue; //<--- safe to call, index will be increased
    //...
}

ALTER TABLE, set null in not null column, PostgreSQL 9.1

Execute the command in this format:

ALTER [ COLUMN ] column { SET | DROP } NOT NULL

Reloading submodules in IPython

For some reason, neither %autoreload, nor dreload seem to work for the situation when you import code from one notebook to another. Only plain Python reload works:

reload(module)

Based on [1].

How to set image in circle in swift

You can simple create extension:

import UIKit

extension UIImageView {

   func setRounded() {
      let radius = CGRectGetWidth(self.frame) / 2
      self.layer.cornerRadius = radius
      self.layer.masksToBounds = true
   }
}

and use it as below:

imageView.setRounded()

How do I calculate square root in Python?

What you're seeing is integer division. To get floating point division by default,

from __future__ import division

Or, you could convert 1 or 2 of 1/2 into a floating point value.

sqrt = x**(1.0/2)

A TypeScript GUID class?

I found this https://typescriptbcl.codeplex.com/SourceControl/latest

here is the Guid version they have in case the link does not work later.

module System {
    export class Guid {
        constructor (public guid: string) {
            this._guid = guid;
        }

        private _guid: string;

        public ToString(): string {
            return this.guid;
        }

        // Static member
        static MakeNew(): Guid {
            var result: string;
            var i: string;
            var j: number;

            result = "";
            for (j = 0; j < 32; j++) {
                if (j == 8 || j == 12 || j == 16 || j == 20)
                    result = result + '-';
                i = Math.floor(Math.random() * 16).toString(16).toUpperCase();
                result = result + i;
            }
            return new Guid(result);
        }
    }
}

How to change the Content of a <textarea> with JavaScript

Like this:

document.getElementById('myTextarea').value = '';

or like this in jQuery:

$('#myTextarea').val('');

Where you have

<textarea id="myTextarea" name="something">This text gets removed</textarea>

For all the downvoters and non-believers:

Powershell script to check if service is started, if not then start it

The below is a compact script that will check if "running" and attempt start service until the service returns as running.

$Service = 'ServiceName'
If ((Get-Service $Service).Status -ne 'Running') {
   do {
       Start-Service $Service -ErrorAction SilentlyContinue
       Start-Sleep 10
   } until ((Get-Service $Service).Status -eq 'Running')
} Return "$($Service) has STARTED"

Shell script variable not empty (-z option)

Of course it does. After replacing the variable, it reads [ !-z ], which is not a valid [ command. Use double quotes, or [[.

if [ ! -z "$errorstatus" ]

if [[ ! -z $errorstatus ]]

How do I make a transparent border with CSS?

The easiest solution to this is to use rgba as the color: border-color: rgba(0,0,0,0); That is fully transparent border color.

How can I find which tables reference a given table in Oracle SQL Developer?

You may be able to query this from the ALL_CONSTRAINTS view:

SELECT table_name
FROM ALL_CONSTRAINTS
WHERE constraint_type = 'R' -- "Referential integrity"
  AND r_constraint_name IN
    ( SELECT constraint_name
      FROM ALL_CONSTRAINTS
      WHERE table_name = 'EMP'
        AND constraint_type IN ('U', 'P') -- "Unique" or "Primary key"
    );

Populating VBA dynamic arrays

I see many (all) posts above relying on LBound/UBound calls upon yet potentially uninitialized VBA dynamic array, what causes application's inevitable death ...

Erratic code:

Dim x As Long Dim arr1() As SomeType ... x = UBound(arr1) 'crashes

Correct code:

Dim x As Long Dim arr1() As SomeType ... ReDim Preserve arr1(0 To 0) ... x = UBound(arr1)

... i.e. any code where Dim arr1() is followed immediatelly by LBound(arr1)/UBound(arr1) calls without ReDim arr1(...) in between, crashes. The roundabout is to employ an On Error Resume Next and check the Err.Number right after the LBound(arr1)/UBound(arr1) call - it should be 0 if the array is initialized, otherwise non-zero. As there is some VBA built-in misbehavior, the further check of array's limits is needed. Detailed explanation may everybody read at Chip Pearson's website (which should be celebrated as a Mankind Treasure Of VBA Wisdom ...)

Heh, that's my first post, believe it is legible.

ADB No Devices Found

I have found a solution (for Windows 7):

  1. Connect your Nexus 10 to PC
  2. Go to Windows Device Manager
  3. RClick on ADB Interface -> properties
  4. Details -> Hardware Ids.

You will see two records like these:

USB\VID_18D1&PID_4EE2
USB\VID_18D1&PID_4EE2&MI_01

5 Open the android_winusb.inf file (I have it in "C:\Users\<username>\AppData\Local\Android\android-sdk\extras\google\usb_driver" directory)

6 Create such records in [Google.NTx86] and [Google.NTamd64] sections using Hardware Ids from properties of ADB interface:

;Google Nexus 10
%SingleAdbInterface% = USB_Install, USB\VID_18D1&PID_4EE2
%CompositeAdbInterface% = USB_Install, USB\VID_18D1&PID_4EE2&MI_01

7 Save the file, and update driver for ADB Interface with showing the path to "C:\Users\\AppData\Local\Android\android-sdk\extras\google\usb_driver" directory

Convert a PHP script into a stand-alone windows executable

The current PHP Nightrain (4.0.0) is written in Python and it uses the wxPython libraries. So far wxPython has been working well to get PHP Nightrain where it is today but in order to push PHP Nightrain to its next level, we are introducing a sibling of PHP Nightrain, the PHPWebkit!

It's an update to PHP Nightrain.

https://github.com/entrypass/nightrain-ep

What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?

I see all the answers here explaining how to work with arrays and how to avoid the index out of bounds exceptions. I personally avoid arrays at all costs. I use the Collections classes, which avoids all the silliness of having to deal with array indices entirely. The looping constructs work beautifully with collections supporting code that is both easier to write, understand and maintain.

Remove everything after a certain character

It can easly be done using JavaScript for reference see link JS String

EDIT it can easly done as. ;)

var url="/Controller/Action?id=11112&value=4444 ";
var parameter_Start_index=url.indexOf('?');
var action_URL = url.substring(0, parameter_Start_index);
alert('action_URL : '+action_URL);

Get first key in a (possibly) associative array?

This could also be a solution:

$yourArray = array('first_key'=> 'First', 2, 3, 4, 5);
$first_key = current(array_flip($yourArray));
echo $first_key;

I have tested it and it works.

Working Code.

How to create a folder with name as current date in batch (.bat) files

https://stackoverflow.com/a/31789045/1010918 foxidrive's answer helped me get the folder with the date and time I wanted. I would like to share this method here since it worked great for me and I think it could help other people too, regardless of their locale.

rem The four lines below will give you reliable YY DD MM YYYY HH Min Sec MS variables in XP Pro and higher.

for /f "tokens=2 delims==" %%a in ('wmic OS Get localdatetime /value') do set "dt=%%a"
set "YY=%dt:~2,2%" & set "YYYY=%dt:~0,4%" & set "MM=%dt:~4,2%" & set "DD=%dt:~6,2%"
set "HH=%dt:~8,2%" & set "Min=%dt:~10,2%" & set "Sec=%dt:~12,2%" & set "MS=%dt:~15,3%"

 set "dirname=%YYYY%-%MM%-%DD% %HH%-%Min%-%Sec%"

 :: remove echo here if you like
 echo "dirName"="%dirName%"

How to get twitter bootstrap modal to close (after initial launch)

I had the same problem in the iphone or desktop, didnt manage to close the dialog when pressing the close button.

i found out that The <button> tag defines a clickable button and is needed to specify the type attribute for a element as follow:

<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>

check the example code for bootstrap modals at : BootStrap javascript Page

How to iterate over the keys and values with ng-repeat in AngularJS?

You can do it in your javascript (controller) or in your html (angular view)...

js:

$scope.arr = [];
for ( p in data ) {
  $scope.arr.push(p); 
}

html:

<tr ng-repeat="(k, v) in data">
    <td>{{k}}<input type="text" ng-model="data[k]"></td>
</tr>

I believe the html way is more angular , but you can also do in your controller and retrieve it in your html...

also not a bad idea to look at the Object keys, they give you the an array of the keys if you need them, more info here:

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/keys

Difference between frontend, backend, and middleware in web development

Generally speaking, people refer to an application's presentation layer as its front end, its persistence layer (database, usually) as the back end, and anything between as middle tier. This set of ideas is often referred to as 3-tier architecture. They let you separate your application into more easily comprehensible (and testable!) chunks; you can also reuse lower-tier code more easily in higher tiers.

Which code is part of which tier is somewhat subjective; graphic designers tend to think of everything that isn't presentation as the back end, database people think of everything in front of the database as the front end, and so on.

Not all applications need to be separated out this way, though. It's certainly more work to have 3 separate sub-projects than it is to just open index.php and get cracking; depending on (1) how long you expect to have to maintain the app (2) how complex you expect the app to get, you may want to forgo the complexity.

How can I run a windows batch file but hide the command window?

1,Download the bat to exe converter and install it 2,Run the bat to exe application 3,Download .pco images if you want to make good looking exe 4,specify the bat file location(c:\my.bat) 5,Specify the location for saving the exe(ex:c:/my.exe) 6,Select Version Information Tab 7,Choose the icon file (downloaded .pco image) 8,if you want fill the information like version,comapny name etc 9,change the tab to option 10,Select the invisible application(This will hide the command prompt while running the application) 11,Choose 32 bit(if you select 64 bit exe will work only in 32 bit OS) 12,Compile 13,Copy the exe to the location where bat file executed properly 14,Run the exe

ImportError: cannot import name main when running pip --version command in windows7 32 bit

In our case, in 2020 using Python3, the solution to this problem was to move the Python installation to the cloud-init startup script which instantiated the VM.

We had been encountering this same error when we had been trying to install Python using scripts that were called by users later in the VM's life cycle, but moving the same Python installation code to the cloud-init script eliminated this problem.

SQLite - UPSERT *not* INSERT or REPLACE

INSERT OR REPLACE is NOT equivalent to "UPSERT".

Say I have the table Employee with the fields id, name, and role:

INSERT OR REPLACE INTO Employee ("id", "name", "role") VALUES (1, "John Foo", "CEO")
INSERT OR REPLACE INTO Employee ("id", "role") VALUES (1, "code monkey")

Boom, you've lost the name of the employee number 1. SQLite has replaced it with a default value.

The expected output of an UPSERT would be to change the role and to keep the name.

#1062 - Duplicate entry for key 'PRIMARY'

You need to remove shares as your PRIMARY KEY OR UNIQUE_KEY

How to generate a create table script for an existing table in phpmyadmin?

Mysqladmin can do the job of saving out the create table script.

Step 1, create a table, insert some rows:

create table penguins (id int primary key, myval varchar(50))
insert into penguins values(2, 'werrhhrrhrh')
insert into penguins values(25, 'weeehehehehe')
select * from penguins

Step 2, use mysql dump command:

mysqldump --no-data --skip-comments --host=your_database_hostname_or_ip.com -u your_username --password=your_password your_database_name penguins > penguins.sql

Step 3, observe the output in penguins.sql:

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
DROP TABLE IF EXISTS `penguins`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `penguins` (
  `id` int(11) NOT NULL,
  `myval` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
/*!40101 SET character_set_client = @saved_cs_client */;
/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;

/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

The output is cluttered by a number of executional-condition tokens above and below. You can filter them out if you don't want them in the next step.

Step 4 (Optional), filter out those extra executional-condition tokens this way:

mysqldump --no-data --skip-comments --compact --host=your_database_hostname_or_ip.com -u your_username --password=your_password your_database_name penguins > penguins.sql

Which produces final output:

eric@dev /home/el $ cat penguins.sql

DROP TABLE IF EXISTS `penguins`;
CREATE TABLE `penguins` (
  `id` int(11) NOT NULL,
  `myval` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Detect if user is scrolling

this works:

window.onscroll = function (e) {  
// called when the window is scrolled.  
} 

edit:

you said this is a function in a TimeInterval..
Try doing it like so:

userHasScrolled = false;
window.onscroll = function (e)
{
    userHasScrolled = true;
}

then inside your Interval insert this:

if(userHasScrolled)
{
//do your code here
userHasScrolled = false;
}

Debugging JavaScript in IE7

It's not a full debugger, but my DP_DEBUG extensions provides some (I think) usful functionality and they work in IE, Firefox and Opera (9+).

You can "dump" visual representations of complex JavaScript objects (even system objects), do simplified logging and timing. The component provides simple methods to enable or disable it so that you can leave the debugger in place for production work if you like.

DP_Debug

Adding a HTTP header to the Angular HttpClient doesn't send the header, why?

set http headers like below in your http request

return this.http.get(url, { headers: new HttpHeaders({'Authorization': 'Bearer ' + token})
 });

Disable SSL fallback and use only TLS for outbound connections in .NET? (Poodle mitigation)

If you're curious which protocols .NET supports, you can try HttpClient out on https://www.howsmyssl.com/

// set proxy if you need to
// WebRequest.DefaultWebProxy = new WebProxy("http://localhost:3128");

File.WriteAllText("howsmyssl-httpclient.html", new HttpClient().GetStringAsync("https://www.howsmyssl.com").Result);

// alternative using WebClient for older framework versions
// new WebClient().DownloadFile("https://www.howsmyssl.com/", "howsmyssl-webclient.html");

The result is damning:

Your client is using TLS 1.0, which is very old, possibly susceptible to the BEAST attack, and doesn't have the best cipher suites available on it. Additions like AES-GCM, and SHA256 to replace MD5-SHA-1 are unavailable to a TLS 1.0 client as well as many more modern cipher suites.

As Eddie explains above, you can enable better protocols manually:

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11; 

I don't know why it uses bad protocols out-the-box. That seems a poor setup choice, tantamount to a major security bug (I bet plenty of applications don't change the default). How can we report it?

A long bigger than Long.MAX_VALUE

That method can't return true. That's the point of Long.MAX_VALUE. It would be really confusing if its name were... false. Then it should be just called Long.SOME_FAIRLY_LARGE_VALUE and have literally zero reasonable uses. Just use Android's isUserAGoat, or you may roll your own function that always returns false.

Note that a long in memory takes a fixed number of bytes. From Oracle:

long: The long data type is a 64-bit signed two's complement integer. It has a minimum value of -9,223,372,036,854,775,808 and a maximum value of 9,223,372,036,854,775,807 (inclusive). Use this data type when you need a range of values wider than those provided by int.

As you may know from basic computer science or discrete math, there are 2^64 possible values for a long, since it is 64 bits. And as you know from discrete math or number theory or common sense, if there's only finitely many possibilities, one of them has to be the largest. That would be Long.MAX_VALUE. So you are asking something similar to "is there an integer that's >0 and < 1?" Mathematically nonsensical.

If you actually need this for something for real then use BigInteger class.

How to submit an HTML form without redirection

Using this snippet, you can submit the form and avoid redirection. Instead you can pass the success function as argument and do whatever you want.

function submitForm(form, successFn){
    if (form.getAttribute("id") != '' || form.getAttribute("id") != null){
        var id = form.getAttribute("id");
    } else {
        console.log("Form id attribute was not set; the form cannot be serialized");
    }

    $.ajax({
        type: form.method,
        url: form.action,
        data: $(id).serializeArray(),
        dataType: "json",
        success: successFn,
        //error: errorFn(data)
    });
}

And then just do:

var formElement = document.getElementById("yourForm");
submitForm(formElement, function() {
    console.log("Form submitted");
});

How to download Javadoc to read offline?

For any javadoc (not just the ones available for download) you can use the DownThemAll addon for Firefox with a suitable renaming mask, for example:

*subdirs*/*name*.*ext*

https://addons.mozilla.org/en-us/firefox/addon/downthemall/

https://www.downthemall.org/main/install-it/downthemall-3-0-7/

Edit: It's possible to use some older versions of the DownThemAll add-on with Pale Moon browser.

Plot bar graph from Pandas DataFrame

To plot just a selection of your columns you can select the columns of interest by passing a list to the subscript operator:

ax = df[['V1','V2']].plot(kind='bar', title ="V comp", figsize=(15, 10), legend=True, fontsize=12)

What you tried was df['V1','V2'] this will raise a KeyError as correctly no column exists with that label, although it looks funny at first you have to consider that your are passing a list hence the double square brackets [[]].

import matplotlib.pyplot as plt
ax = df[['V1','V2']].plot(kind='bar', title ="V comp", figsize=(15, 10), legend=True, fontsize=12)
ax.set_xlabel("Hour", fontsize=12)
ax.set_ylabel("V", fontsize=12)
plt.show()

enter image description here

How can I find my php.ini on wordpress?

If you use cPanel and have installed CloudLinux you can go to section Software > Select PHP Version > Switch To PHP Options and define max_execution_time among other options.

Short gif: http://cloud.mercadoalvo.com/nDdE

Java String to Date object of the format "yyyy-mm-dd HH:mm:ss"

java.util.Date temp = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSSSS").parse("2012-07-10 14:58:00.000000");

The mm is minutes you want MM

CODE

public class Test {

    public static void main(String[] args) throws ParseException {
        java.util.Date temp = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSSSS")
                .parse("2012-07-10 14:58:00.000000");
        System.out.println(temp);
    }
}

Prints:

Tue Jul 10 14:58:00 EDT 2012

error::make_unique is not a member of ‘std’

If you are stuck with c++11, you can get make_unique from abseil-cpp, an open source collection of C++ libraries drawn from Google’s internal codebase.

Jenkins vs Travis-CI. Which one would you use for a Open Source project?

I worked on both Travis and Jenkins: I will list down some of the features of both:

Setup CI for a project

Travis comes in first place. It's very easy to setup. Takes less than a minute to setup with GitHub.

  1. Login to GitHub
  2. Create Web Hook for Travis.
  3. Return to Travis, and login with your GitHub credentials
  4. Sync your GitHub repo and enable Push and Pull requests.

Jenkins:

  1. Create an Environment (Master Jenkins)
  2. Create web hooks
  3. Configure each job (takes time compare to Travis)

Re-running builds

Travis: Anyone with write access on GitHub can re-run the build by clicking on `restart build

Jenkins: Re-run builds based on a phrase. You provide phrase text in PR/commit description, like reverify jenkins.

Controlling environment

Travis: Travis provides hosted environment. It installs required software for every build. It’s a time-consuming process.

Jenkins: One-time setup. Installs all required software on a node/slave machine, and then builds/tests on a pre-installed environment.

Build Logs:

Travis: Supports build logs to place in Amazon S3.

Jenkins: Easy to setup with build artifacts plugin.

How to deal with SettingWithCopyWarning in Pandas

Some may want to simply suppress the warning:

class SupressSettingWithCopyWarning:
    def __enter__(self):
        pd.options.mode.chained_assignment = None

    def __exit__(self, *args):
        pd.options.mode.chained_assignment = 'warn'

with SupressSettingWithCopyWarning():
    #code that produces warning

Maven error :Perhaps you are running on a JRE rather than a JDK?

If the above solutions doesn't work then try to place java path before maven in path of environment variable. It worked for me.

%JAVA_HOME%\bin

C:\Program Files\apache-maven-3.6.1-bin\apache-maven-3.6.1\bin

PHP Echo a large block of text

One option is to get out of the php block and just write HTML.

With your code, after the opening curly brace of your if statement, end the PHP:

if (is_single()) { ?>

Then remove the echo ' and the ';

After all your html and css, before the closing }, write:

<? } else {

If the text you want to write to the page is dynamic, it gets a little trickier, but for now this should work fine.

Generate PDF from HTML using pdfMake in Angularjs

Okay, I figured this out.

  1. You will need html2canvas and pdfmake. You do NOT need to do any injection in your app.js to either, just include in your script tags

  2. On the div that you want to create the PDF of, add an ID name like below:

     <div id="exportthis">
    
  3. In your Angular controller use the id of the div in your call to html2canvas:

  4. change the canvas to an image using toDataURL()

  5. Then in your docDefinition for pdfmake assign the image to the content.

  6. The completed code in your controller will look like this:

           html2canvas(document.getElementById('exportthis'), {
                onrendered: function (canvas) {
                    var data = canvas.toDataURL();
                    var docDefinition = {
                        content: [{
                            image: data,
                            width: 500,
                        }]
                    };
                    pdfMake.createPdf(docDefinition).download("Score_Details.pdf");
                }
            });
    

I hope this helps someone else. Happy coding!

determine DB2 text string length

Mostly we write below statement select * from table where length(ltrim(rtrim(field)))=10;

Parse strings to double with comma and point

Extension to parse decimal number from string.

  • No matter number will be on the beginning, in the end, or in the middle of a string.
  • No matter if there will be only number or lot of "garbage" letters.
  • No matter what is delimiter configured in the cultural settings on the PC: it will parse dot and comma both correctly.
  • Ability to set decimal symbol manually.

    public static class StringExtension
    {
        public static double DoubleParseAdvanced(this string strToParse, char decimalSymbol = ',')
        {
            string tmp = Regex.Match(strToParse, @"([-]?[0-9]+)([\s])?([0-9]+)?[." + decimalSymbol + "]?([0-9 ]+)?([0-9]+)?").Value;
    
            if (tmp.Length > 0 && strToParse.Contains(tmp))
            {
                var currDecSeparator = System.Windows.Forms.Application.CurrentCulture.NumberFormat.NumberDecimalSeparator;
    
                tmp = tmp.Replace(".", currDecSeparator).Replace(decimalSymbol.ToString(), currDecSeparator);
    
                return double.Parse(tmp);
            }
    
            return 0;
        }
    }
    

How to use:

"It's 4.45 O'clock now".DoubleParseAdvanced(); // will return 4.45
"It's 4,45 O'clock now".DoubleParseAdvanced(); // will return 4.45
"It's 4:45 O'clock now".DoubleParseAdvanced(':'); // will return 4.45

Extracting double-digit months and days from a Python date

you can use a string formatter to pad any integer with zeros. It acts just like C's printf.

>>> d = datetime.date.today()
>>> '%02d' % d.month
'03'

Updated for py36: Use f-strings! For general ints you can use the d formatter and explicitly tell it to pad with zeros:

 >>> d = datetime.date.today()
 >>> f"{d.month:02d}"
 '07'

But datetimes are special and come with special formatters that are already zero padded:

 >>> f"{d:%d}"  # the day
 '01'
 >>> f"{d:%m}"  # the month
 '07'

Does Go have "if x in" construct similar to Python?

This is as close as I can get to the natural feel of Python's "in" operator. You have to define your own type. Then you can extend the functionality of that type by adding a method like "has" which behaves like you'd hope.

package main

import "fmt"

type StrSlice []string

func (list StrSlice) Has(a string) bool {
    for _, b := range list {
        if b == a {
            return true
        }
    }
    return false
}

func main() {
    var testList = StrSlice{"The", "big", "dog", "has", "fleas"}

    if testList.Has("dog") {
        fmt.Println("Yay!")
    }
}

I have a utility library where I define a few common things like this for several types of slices, like those containing integers or my own other structs.

Yes, it runs in linear time, but that's not the point. The point is to ask and learn what common language constructs Go has and doesn't have. It's a good exercise. Whether this answer is silly or useful is up to the reader.

How to use onClick event on react Link component?

You should use this:

<Link to={this.props.myroute} onClick={hello}>Here</Link>

Or (if method hello lays at this class):

<Link to={this.props.myroute} onClick={this.hello}>Here</Link>

Update: For ES6 and latest if you want to bind some param with click method, you can use this:

    const someValue = 'some';  
....  
    <Link to={this.props.myroute} onClick={() => hello(someValue)}>Here</Link>

Create an Oracle function that returns a table

To return the whole table at once you could change the SELECT to:

SELECT  ...
BULK COLLECT INTO T
FROM    ...

This is only advisable for results that aren't excessively large, since they all have to be accumulated in memory before being returned; otherwise consider the pipelined function as suggested by Charles, or returning a REF CURSOR.

Print array without brackets and commas

If you use Java8 or above, you can use with stream() with native.

publicArray.stream()
        .map(Object::toString)
        .collect(Collectors.joining(" "));

References

Using if-else in JSP

You may try this example:

_x000D_
_x000D_
<form>_x000D_
  <h1>Hello! I'm duke! What's you name?</h1>_x000D_
  <input type="text" name="user">_x000D_
  <br>_x000D_
  <br>_x000D_
  <input type="submit" value="submit">&nbsp;&nbsp;&nbsp;&nbsp;_x000D_
  <input type="reset">_x000D_
</form>_x000D_
<h1>Hello ${param.user}</h1> _x000D_
<!-- its Expression Language -->
_x000D_
_x000D_
_x000D_

How to create an on/off switch with Javascript/CSS?

You can achieve this using HTML and CSS and convert a checkbox into a HTML Switch.

HTML

      <div class="switch">
        <input id="cmn-toggle-1" class="cmn-toggle cmn-toggle-round"  type="checkbox">
        <label for="cmn-toggle-1"></label>
      </div>

CSS

input.cmn-toggle-round + label {
  padding: 2px;
  width: 100px;
  height: 30px;
  background-color: #dddddd;
  -webkit-border-radius: 30px;
  -moz-border-radius: 30px;
  -ms-border-radius: 30px;
  -o-border-radius: 30px;
  border-radius: 30px;
}
input.cmn-toggle-round + label:before, input.cmn-toggle-round + label:after {
  display: block;
  position: absolute;
  top: 1px;
  left: 1px;
  bottom: 1px;
  content: "";
}
input.cmn-toggle-round + label:before {
  right: 1px;
  background-color: #f1f1f1;
  -webkit-border-radius: 30px;
  -moz-border-radius: 30px;
  -ms-border-radius: 30px;
  -o-border-radius: 30px;
  border-radius: 30px;
  -webkit-transition: background 0.4s;
  -moz-transition: background 0.4s;
  -o-transition: background 0.4s;
  transition: background 0.4s;
}
input.cmn-toggle-round + label:after {
  width: 40px;
  background-color: #fff;
  -webkit-border-radius: 100%;
  -moz-border-radius: 100%;
  -ms-border-radius: 100%;
  -o-border-radius: 100%;
  border-radius: 100%;
  -webkit-box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
  -moz-box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
  -webkit-transition: margin 0.4s;
  -moz-transition: margin 0.4s;
  -o-transition: margin 0.4s;
  transition: margin 0.4s;
}
input.cmn-toggle-round:checked + label:before {
  background-color: #8ce196;
}
input.cmn-toggle-round:checked + label:after {
  margin-left: 60px;
}

.cmn-toggle {
  position: absolute;
  margin-left: -9999px;
  visibility: hidden;
}
.cmn-toggle + label {
  display: block;
  position: relative;
  cursor: pointer;
  outline: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

DEMO

How to use z-index in svg elements?

The clean, fast, and easy solutions posted as of the date of this answer are unsatisfactory. They are constructed over the flawed statement that SVG documents lack z order. Libraries are not necessary either. One line of code can perform most operations to manipulate the z order of objects or groups of objects that might be required in the development of an app that moves 2D objects around in an x-y-z space.

Z Order Definitely Exists in SVG Document Fragments

What is called an SVG document fragment is a tree of elements derived from the base node type SVGElement. The root node of an SVG document fragment is an SVGSVGElement, which corresponds to an HTML5 <svg> tag. The SVGGElement corresponds to the <g> tag and permits aggregating children.

Having a z-index attribute on the SVGElement as in CSS would defeat the SVG rendering model. Sections 3.3 and 3.4 of W3C SVG Recommendation v1.1 2nd Edition state that SVG document fragments (trees of offspring from an SVGSVGElement) are rendered using what is called a depth first search of the tree. That scheme is a z order in every sense of the term.

Z order is actually a computer vision shortcut to avoid the need for true 3D rendering with the complexities and computing demands of ray tracing. The linear equation for the implicit z-index of elements in an SVG document fragment.

z-index = z-index_of_svg_tag + depth_first_tree_index / tree_node_qty

This is important because if you want to move a circle that was below a square to above it, you simply insert the square before the circle. This can be done easily in JavaScript.

Supporting Methods

SVGElement instances have two methods that support simple and easy z order manipulation.

  • parent.removeChild(child)
  • parent.insertBefore(child, childRef)

The Correct Answer That Doesn't Create a Mess

Because the SVGGElement (<g> tag) can be removed and inserted just as easily as a SVGCircleElement or any other shape, image layers typical of Adobe products and other graphics tools can be implemented with ease using the SVGGElement. This JavaScript is essentially a Move Below command.

parent.insertBefore(parent.removeChild(gRobot), gDoorway)

If the layer of a robot drawn as children of SVGGElement gRobot was before the doorway drawn as children of SVGGElement gDoorway, the robot is now behind the doorway because the z order of the doorway is now one plus the z order of the robot.

A Move Above command is almost as easy.

parent.insertBefore(parent.removeChild(gRobot), gDoorway.nextSibling())

Just think a=a and b=b to remember this.

insert after = move above
insert before = move below

Leaving the DOM in a State Consistent With the View

The reason this answer is correct is because it is minimal and complete and, like the internals of Adobe products or other well designed graphics editors, leaves the internal representation in a state that is consistent with the view created by rendering.

Alternative But Limited Approach

Another approach commonly used is to use CSS z-index in conjunction with multiple SVG document fragments (SVG tags) with mostly transparent backgrounds in all but the bottom one. Again, this defeats the elegance of the SVG rendering model, making it difficult to move objects up or down in the z order.


NOTES:

  1. (https://www.w3.org/TR/SVG/render.html v 1.1, 2nd Edition, 16 August 2011)

    3.3 Rendering Order Elements in an SVG document fragment have an implicit drawing order, with the first elements in the SVG document fragment getting "painted" first. Subsequent elements are painted on top of previously painted elements.

    3.4 How groups are rendered Grouping elements such as the ‘g’ element (see container elements) have the effect of producing a temporary separate canvas initialized to transparent black onto which child elements are painted. Upon the completion of the group, any filter effects specified for the group are applied to create a modified temporary canvas. The modified temporary canvas is composited into the background, taking into account any group-level masking and opacity settings on the group.

XCOPY: Overwrite all without prompt in BATCH

The solution is the /Y switch:

xcopy "C:\Users\ADMIN\Desktop\*.*" "D:\Backup\" /K /D /H /Y

Twitter Bootstrap: Print content of modal window

Heres a solution with no Javascript or plugin - just some css and one extra class in the markup. This solutions uses the fact that BootStrap adds a class to the body when a dialog is open. We use this class to then hide the body, and print only the dialog.

To ensure we can determine the main body of the page we need to contain everything within the main page content in a div - I've used id="mainContent". Sample Page layout below - with a main page and two dialogs

<body>
 <div class="container body-content">

  <div id="mainContent">
       main page stuff     
  </div>
  <!-- Dialog One -->
  <div class="modal fade in">
   <div class="modal-dialog">
    <div class="modal-content">
          ...
    </div>
   </div>
  </div>

  <!-- Dialog Two -->
  <div class="modal fade in">
   <div class="modal-dialog">
    <div class="modal-content">
          ...
    </div>
   </div>
  </div>

 </div>
</body>

Then in our CSS print media queries, I use display: none to hide everything I don't want displayed - ie the mainContent when a dialog is open. I also use a specific class noPrint to be used on any parts of the page that should not be displayed - say action buttons. Here I am also hiding the headers and footers. You may need to tweak it to get exactly want you want.

@media print {
    header, .footer, footer {
        display: none;
    }

    /* hide main content when dialog open */
    body.modal-open div.container.body-content div#mainContent {
        display: none;
    }

    .noPrint {
        display: none;
    }
}

How to resize an Image C#

You could try net-vips, the C# binding for libvips. It's a lazy, streaming, demand-driven image processing library, so it can do operations like this without needing to load the whole image.

For example, it comes with a handy image thumbnailer:

Image image = Image.Thumbnail("image.jpg", 300, 300);
image.WriteToFile("my-thumbnail.jpg");

It also supports smart crop, a way of intelligently determining the most important part of the image and keeping it in focus while cropping the image. For example:

Image image = Image.Thumbnail("owl.jpg", 128, crop: "attention");
image.WriteToFile("tn_owl.jpg");

Where owl.jpg is an off-centre composition:

Owl

Gives this result:

Owl smart crop

First it shrinks the image to get the vertical axis to 128 pixels, then crops down to 128 pixels across using the attention strategy. This one searches the image for features which might catch a human eye, see Smartcrop() for details.

How do I check if an object's type is a particular subclass in C++?

I don't know if I understand your problem correctly, so let me restate it in my own words...

Problem: Given classes B and D, determine if D is a subclass of B (or vice-versa?)

Solution: Use some template magic! Okay, seriously you need to take a look at LOKI, an excellent template meta-programming library produced by the fabled C++ author Andrei Alexandrescu.

More specifically, download LOKI and include header TypeManip.h from it in your source code then use the SuperSubclass class template as follows:

if(SuperSubClass<B,D>::value)
{
...
}

According to documentation, SuperSubClass<B,D>::value will be true if B is a public base of D, or if B and D are aliases of the same type.

i.e. either D is a subclass of B or D is the same as B.

I hope this helps.

edit:

Please note the evaluation of SuperSubClass<B,D>::value happens at compile time unlike some methods which use dynamic_cast, hence there is no penalty for using this system at runtime.

Programmatically get the version number of a DLL

Kris, your version works great when needing to load the assembly from the actual DLL file (and if the DLL is there!), however, one will get a much unwanted error if the DLL is EMBEDDED (i.e., not a file but an embedded DLL).

The other thing is, if one uses a versioning scheme with something like "1.2012.0508.0101", when one gets the version string you'll actually get "1.2012.518.101"; note the missing zeros.

So, here's a few extra functions to get the version of a DLL (embedded or from the DLL file):

    public static System.Reflection.Assembly GetAssembly(string pAssemblyName)
    {
        System.Reflection.Assembly tMyAssembly = null;

        if (string.IsNullOrEmpty(pAssemblyName)) { return tMyAssembly; }
        tMyAssembly = GetAssemblyEmbedded(pAssemblyName);
        if (tMyAssembly == null) { GetAssemblyDLL(pAssemblyName); }

        return tMyAssembly;
    }//System.Reflection.Assembly GetAssemblyEmbedded(string pAssemblyDisplayName)


    public static System.Reflection.Assembly GetAssemblyEmbedded(string pAssemblyDisplayName)
    {
        System.Reflection.Assembly tMyAssembly = null;

        if(string.IsNullOrEmpty(pAssemblyDisplayName)) { return tMyAssembly; }
        try //try #a
        {
            tMyAssembly = System.Reflection.Assembly.Load(pAssemblyDisplayName);
        }// try #a
        catch (Exception ex)
        {
            string m = ex.Message;
        }// try #a
        return tMyAssembly;
    }//System.Reflection.Assembly GetAssemblyEmbedded(string pAssemblyDisplayName)


    public static System.Reflection.Assembly GetAssemblyDLL(string pAssemblyNameDLL)
    {
        System.Reflection.Assembly tMyAssembly = null;

        if (string.IsNullOrEmpty(pAssemblyNameDLL)) { return tMyAssembly; }
        try //try #a
        {
            if (!pAssemblyNameDLL.ToLower().EndsWith(".dll")) { pAssemblyNameDLL += ".dll"; }
            tMyAssembly = System.Reflection.Assembly.LoadFrom(pAssemblyNameDLL);
        }// try #a
        catch (Exception ex)
        {
            string m = ex.Message;
        }// try #a
        return tMyAssembly;
    }//System.Reflection.Assembly GetAssemblyFile(string pAssemblyNameDLL)


    public static string GetVersionStringFromAssembly(string pAssemblyDisplayName)
    {
        string tVersion = "Unknown";
        System.Reflection.Assembly tMyAssembly = null;

        tMyAssembly = GetAssembly(pAssemblyDisplayName);
        if (tMyAssembly == null) { return tVersion; }
        tVersion = GetVersionString(tMyAssembly.GetName().Version.ToString());
        return tVersion;
    }//string GetVersionStringFromAssemblyEmbedded(string pAssemblyDisplayName)


    public static string GetVersionString(Version pVersion)
    {
        string tVersion = "Unknown";
        if (pVersion == null) { return tVersion; }
        tVersion = GetVersionString(pVersion.ToString());
        return tVersion;
    }//string GetVersionString(Version pVersion)


    public static string GetVersionString(string pVersionString)
    {
        string tVersion = "Unknown";
        string[] aVersion;

        if (string.IsNullOrEmpty(pVersionString)) { return tVersion; }
        aVersion = pVersionString.Split('.');
        if (aVersion.Length > 0) { tVersion = aVersion[0]; }
        if (aVersion.Length > 1) { tVersion += "." + aVersion[1]; }
        if (aVersion.Length > 2) { tVersion += "." + aVersion[2].PadLeft(4, '0'); }
        if (aVersion.Length > 3) { tVersion += "." + aVersion[3].PadLeft(4, '0'); }

        return tVersion;
    }//string GetVersionString(Version pVersion)


    public static string GetVersionStringFromAssemblyEmbedded(string pAssemblyDisplayName)
    {
        string tVersion = "Unknown";
        System.Reflection.Assembly tMyAssembly = null;

        tMyAssembly = GetAssemblyEmbedded(pAssemblyDisplayName);
        if (tMyAssembly == null) { return tVersion; }
        tVersion = GetVersionString(tMyAssembly.GetName().Version.ToString());
        return tVersion;
    }//string GetVersionStringFromAssemblyEmbedded(string pAssemblyDisplayName)


    public static string GetVersionStringFromAssemblyDLL(string pAssemblyDisplayName)
    {
        string tVersion = "Unknown";
        System.Reflection.Assembly tMyAssembly = null;

        tMyAssembly = GetAssemblyDLL(pAssemblyDisplayName);
        if (tMyAssembly == null) { return tVersion; }
        tVersion = GetVersionString(tMyAssembly.GetName().Version.ToString());
        return tVersion;
    }//string GetVersionStringFromAssemblyEmbedded(string pAssemblyDisplayName)

How do I parse a string to a float or int?

Use:

>>> str_float = "545.2222"
>>> float(str_float)
545.2222
>>> type(_) # Check its type
<type 'float'>

>>> str_int = "31"
>>> int(str_int)
31
>>> type(_) # Check its type
<type 'int'>

Aggregate function in SQL WHERE-Clause

UPDATED query:

select id from t where id < (select max(id) from t);

It'll select all but the last row from the table t.

Creating SVG graphics using Javascript?

I found no complied answer so to create circle and add to svg try this:

_x000D_
_x000D_
var svgns = "http://www.w3.org/2000/svg";_x000D_
var svg = document.getElementById('svg');_x000D_
var shape = document.createElementNS(svgns, "circle");_x000D_
shape.setAttributeNS(null, "cx", 25);_x000D_
shape.setAttributeNS(null, "cy", 25);_x000D_
shape.setAttributeNS(null, "r",  20);_x000D_
shape.setAttributeNS(null, "fill", "green");_x000D_
svg.appendChild(shape);
_x000D_
<svg id="svg" width="100" height="100"></svg>
_x000D_
_x000D_
_x000D_

How would you make a comma-separated string from a list of strings?

Here is an example with list

>>> myList = [['Apple'],['Orange']]
>>> myList = ','.join(map(str, [i[0] for i in myList])) 
>>> print "Output:", myList
Output: Apple,Orange

More Accurate:-

>>> myList = [['Apple'],['Orange']]
>>> myList = ','.join(map(str, [type(i) == list and i[0] for i in myList])) 
>>> print "Output:", myList
Output: Apple,Orange

Example 2:-

myList = ['Apple','Orange']
myList = ','.join(map(str, myList)) 
print "Output:", myList
Output: Apple,Orange

How to get an absolute file path in Python

You could use the new Python 3.4 library pathlib. (You can also get it for Python 2.6 or 2.7 using pip install pathlib.) The authors wrote: "The aim of this library is to provide a simple hierarchy of classes to handle filesystem paths and the common operations users do over them."

To get an absolute path in Windows:

>>> from pathlib import Path
>>> p = Path("pythonw.exe").resolve()
>>> p
WindowsPath('C:/Python27/pythonw.exe')
>>> str(p)
'C:\\Python27\\pythonw.exe'

Or on UNIX:

>>> from pathlib import Path
>>> p = Path("python3.4").resolve()
>>> p
PosixPath('/opt/python3/bin/python3.4')
>>> str(p)
'/opt/python3/bin/python3.4'

Docs are here: https://docs.python.org/3/library/pathlib.html

Making Python loggers output all messages to stdout in addition to log file

Since no one has shared a neat two liner, I will share my own:

logging.basicConfig(filename='logs.log', level=logging.DEBUG, format="%(asctime)s:%(levelname)s: %(message)s")
logging.getLogger().addHandler(logging.StreamHandler())

How to declare a global variable in a .js file

Just define your variables in global.js outside a function scope:

// global.js
var global1 = "I'm a global!";
var global2 = "So am I!";

// other js-file
function testGlobal () {
    alert(global1);
}

To make sure that this works you have to include/link to global.js before you try to access any variables defined in that file:

<html>
    <head>
        <!-- Include global.js first -->
        <script src="/YOUR_PATH/global.js" type="text/javascript"></script>
        <!-- Now we can reference variables, objects, functions etc. 
             defined in global.js -->
        <script src="/YOUR_PATH/otherJsFile.js" type="text/javascript"></script>
    </head>
    [...]
</html>

You could, of course, link in the script tags just before the closing <body>-tag if you do not want the load of js-files to interrupt the initial page load.

How to colorize diff on the command line?

Here is another solution that invokes sed to insert the appropriate ANSI escape sequences for colors to show the +, -, and @ lines in red, green, and cyan, respectively.

diff -u old new | sed "s/^-/$(tput setaf 1)&/; s/^+/$(tput setaf 2)&/; s/^@/$(tput setaf 6)&/; s/$/$(tput sgr0)/"

Unlike the other solutions to this question, this solution does not spell out the ANSI escape sequences explicitly. Instead, it invokes the tput setaf and tput sgr0 commands to generate the ANSI escape sequences to set an appropriate color and reset terminal attributes, respectively.

To see the available colors for each argument to tput setaf, use this command:

for i in {0..255}; do tput setaf $i; printf %4d $i; done; tput sgr0; echo

Here is how the output looks:

enter image description here

Here is the evidence that the tput setaf and tput sgr0 commands generate the appropriate ANSI escape sequences:

$ tput setaf 1 | xxd -g1
00000000: 1b 5b 33 31 6d                                   .[31m
$ tput setaf 2 | xxd -g1
00000000: 1b 5b 33 32 6d                                   .[32m
$ tput setaf 6 | xxd -g1
00000000: 1b 5b 33 36 6d                                   .[36m
$ tput sgr0 | xxd -g1
00000000: 1b 28 42 1b 5b 6d                                .(B.[m

Declaring an enum within a class

  1. If Color is something that is specific to just Cars then that is the way you would limit its scope. If you are going to have another Color enum that other classes use then you might as well make it global (or at least outside Car).

  2. It makes no difference. If there is a global one then the local one is still used anyway as it is closer to the current scope. Note that if you define those function outside of the class definition then you'll need to explicitly specify Car::Color in the function's interface.

How to send a "multipart/form-data" with requests in python?

Basically, if you specify a files parameter (a dictionary), then requests will send a multipart/form-data POST instead of a application/x-www-form-urlencoded POST. You are not limited to using actual files in that dictionary, however:

>>> import requests
>>> response = requests.post('http://httpbin.org/post', files=dict(foo='bar'))
>>> response.status_code
200

and httpbin.org lets you know what headers you posted with; in response.json() we have:

>>> from pprint import pprint
>>> pprint(response.json()['headers'])
{'Accept': '*/*',
 'Accept-Encoding': 'gzip, deflate',
 'Connection': 'close',
 'Content-Length': '141',
 'Content-Type': 'multipart/form-data; '
                 'boundary=c7cbfdd911b4e720f1dd8f479c50bc7f',
 'Host': 'httpbin.org',
 'User-Agent': 'python-requests/2.21.0'}

Better still, you can further control the filename, content type and additional headers for each part by using a tuple instead of a single string or bytes object. The tuple is expected to contain between 2 and 4 elements; the filename, the content, optionally a content type, and an optional dictionary of further headers.

I'd use the tuple form with None as the filename, so that the filename="..." parameter is dropped from the request for those parts:

>>> files = {'foo': 'bar'}
>>> print(requests.Request('POST', 'http://httpbin.org/post', files=files).prepare().body.decode('utf8'))
--bb3f05a247b43eede27a124ef8b968c5
Content-Disposition: form-data; name="foo"; filename="foo"

bar
--bb3f05a247b43eede27a124ef8b968c5--
>>> files = {'foo': (None, 'bar')}
>>> print(requests.Request('POST', 'http://httpbin.org/post', files=files).prepare().body.decode('utf8'))
--d5ca8c90a869c5ae31f70fa3ddb23c76
Content-Disposition: form-data; name="foo"

bar
--d5ca8c90a869c5ae31f70fa3ddb23c76--

files can also be a list of two-value tuples, if you need ordering and/or multiple fields with the same name:

requests.post(
    'http://requestb.in/xucj9exu',
    files=(
        ('foo', (None, 'bar')),
        ('foo', (None, 'baz')),
        ('spam', (None, 'eggs')),
    )
)

If you specify both files and data, then it depends on the value of data what will be used to create the POST body. If data is a string, only it willl be used; otherwise both data and files are used, with the elements in data listed first.

There is also the excellent requests-toolbelt project, which includes advanced Multipart support. It takes field definitions in the same format as the files parameter, but unlike requests, it defaults to not setting a filename parameter. In addition, it can stream the request from open file objects, where requests will first construct the request body in memory:

from requests_toolbelt.multipart.encoder import MultipartEncoder

mp_encoder = MultipartEncoder(
    fields={
        'foo': 'bar',
        # plain file object, no filename or mime type produces a
        # Content-Disposition header with just the part name
        'spam': ('spam.txt', open('spam.txt', 'rb'), 'text/plain'),
    }
)
r = requests.post(
    'http://httpbin.org/post',
    data=mp_encoder,  # The MultipartEncoder is posted as data, don't use files=...!
    # The MultipartEncoder provides the content-type header with the boundary:
    headers={'Content-Type': mp_encoder.content_type}
)

Fields follow the same conventions; use a tuple with between 2 and 4 elements to add a filename, part mime-type or extra headers. Unlike the files parameter, no attempt is made to find a default filename value if you don't use a tuple.

Reset the database (purge all), then seed a database

You can delete everything and recreate database + seeds with both:

  1. rake db:reset: loads from schema.rb
  2. rake db:drop db:create db:migrate db:seed: loads from migrations

Make sure you have no connections to db (rails server, sql client..) or the db won't drop.

schema.rb is a snapshot of the current state of your database generated by:

rake db:schema:dump

What is the meaning of "operator bool() const"

operator bool() const 
{
    return col != 0;
}

Defines how the class is convertable to a boolean value, the const after the () is used to indicate this method does not mutate (change the members of this class).

You would usually use such operators as follows:

airplaysdk sdkInstance;
if (sdkInstance) {
    std::cout << "Instance is active" << std::endl;
} else {
    std::cout << "Instance is in-active error!" << std::endl;
}

How to print multiple lines of text with Python

The triple quotes answer is great for ASCII art, but for those wondering - what if my multiple lines are a tuple, list, or other iterable that returns strings (perhaps a list comprehension?), then how about:

print("\n".join(<*iterable*>))

For example:

print("\n".join(["{}={}".format(k, v) for k, v in os.environ.items() if 'PATH' in k]))

How to check if a file exists in the Documents directory in Swift?

It's pretty user friendly. Just work with NSFileManager's defaultManager singleton and then use the fileExistsAtPath() method, which simply takes a string as an argument, and returns a Bool, allowing it to be placed directly in the if statement.

let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let documentDirectory = paths[0] as! String
let myFilePath = documentDirectory.stringByAppendingPathComponent("nameOfMyFile")

let manager = NSFileManager.defaultManager()
if (manager.fileExistsAtPath(myFilePath)) {
    // it's here!!
}

Note that the downcast to String isn't necessary in Swift 2.

Eclipse EGit Checkout conflict with files: - EGit doesn't want to continue

The proper solution is the one provided by @Jojo.Lechelt.

However if you don't want to commit for any reason and still want to pull the changes,you may save your changes somewhere else,replace the conflicting file with HEAD revision and then pull.

Later you can paste your changes again and compare it with HEAD and incorporate other people changes into your file.

Boolean operators && and ||

The answer about "short-circuiting" is potentially misleading, but has some truth (see below). In the R/S language, && and || only evaluate the first element in the first argument. All other elements in a vector or list are ignored regardless of the first ones value. Those operators are designed to work with the if (cond) {} else{} construction and to direct program control rather than construct new vectors.. The & and the | operators are designed to work on vectors, so they will be applied "in parallel", so to speak, along the length of the longest argument. Both vectors need to be evaluated before the comparisons are made. If the vectors are not the same length, then recycling of the shorter argument is performed.

When the arguments to && or || are evaluated, there is "short-circuiting" in that if any of the values in succession from left to right are determinative, then evaluations cease and the final value is returned.

> if( print(1) ) {print(2)} else {print(3)}
[1] 1
[1] 2
> if(FALSE && print(1) ) {print(2)} else {print(3)} # `print(1)` not evaluated
[1] 3
> if(TRUE && print(1) ) {print(2)} else {print(3)}
[1] 1
[1] 2
> if(TRUE && !print(1) ) {print(2)} else {print(3)}
[1] 1
[1] 3
> if(FALSE && !print(1) ) {print(2)} else {print(3)}
[1] 3

The advantage of short-circuiting will only appear when the arguments take a long time to evaluate. That will typically occur when the arguments are functions that either process larger objects or have mathematical operations that are more complex.

hide/show a image in jquery

If you're trying to hide upload img and show bandwidth img on bandwidth click and viceversa this would work

<script>

    function show_img(id)
    {
        if(id=='bandwidth')
        {
           $("#upload").hide();
           $("#bandwith").show();
        }
        else if(id=='upload')
        {
            $("#upload").show();
            $("#bandwith").hide();
        }
    return false;
     } 
    </script>
    <a href="#" onclick="javascript:show_img('bandwidth');">Bandwidth</a>
    <a href="#" onclick="javascript:show_img('upload');">Upload</a>
    <p align="center"> 
      <img src="/media/img/close.png" style="visibility: hidden;" id="bandwidth"/>
      <img src="/media/img/close.png" style="visibility: hidden;" id="upload"/>
    </p>

JAVA How to remove trailing zeros from a double

Use a DecimalFormat object with a format string of "0.#".

Flutter: RenderBox was not laid out

Placing your list view in a Flexible widget may also help,

Flexible( fit: FlexFit.tight, child: _buildYourListWidget(..),)

Set CFLAGS and CXXFLAGS options using CMake

On Unix systems, for several projects, I added these lines into the CMakeLists.txt and it was compiling successfully because base (/usr/include) and local includes (/usr/local/include) go into separated directories:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I/usr/local/include -L/usr/local/lib")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -I/usr/local/include")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -L/usr/local/lib")

It appends the correct directory, including paths for the C and C++ compiler flags and the correct directory path for the linker flags.

Note: C++ compiler (c++) doesn't support -L, so we have to use CMAKE_EXE_LINKER_FLAGS

python convert list to dictionary

Not sure whether it would help you or not but it works to me:

l = ["a", "b", "c", "d", "e"]
outRes = dict((l[i], l[i+1]) if i+1 < len(l) else (l[i], '') for i in xrange(len(l)))

How to know whether refresh button or browser back button is clicked in Firefox

var keyCode = evt.keyCode;
if (keyCode==8)
alert('you pressed backspace');

if(keyCode==116)
alert('you pressed f5 to reload page')

Interfaces with static fields in java for sharing 'constants'

Given the advantage of hindsight, we can see that Java is broken in many ways. One major failing of Java is the restriction of interfaces to abstract methods and static final fields. Newer, more sophisticated OO languages like Scala subsume interfaces by traits which can (and typically do) include concrete methods, which may have arity zero (constants!). For an exposition on traits as units of composable behavior, see http://scg.unibe.ch/archive/papers/Scha03aTraits.pdf. For a short description of how traits in Scala compare with interfaces in Java, see http://www.codecommit.com/blog/scala/scala-for-java-refugees-part-5. In the context of teaching OO design, simplistic rules like asserting that interfaces should never include static fields are silly. Many traits naturally include constants and these constants are appropriately part of the public "interface" supported by the trait. In writing Java code, there is no clean, elegant way to represent traits, but using static final fields within interfaces is often part of a good workaround.

How to merge two arrays of objects by ID using lodash?

If both arrays are in the correct order; where each item corresponds to its associated member identifier then you can simply use.

var merge = _.merge(arr1, arr2);

Which is the short version of:

var merge = _.chain(arr1).zip(arr2).map(function(item) {
    return _.merge.apply(null, item);
}).value();

Or, if the data in the arrays is not in any particular order, you can look up the associated item by the member value.

var merge = _.map(arr1, function(item) {
    return _.merge(item, _.find(arr2, { 'member' : item.member }));
});

You can easily convert this to a mixin. See the example below:

_x000D_
_x000D_
_.mixin({_x000D_
  'mergeByKey' : function(arr1, arr2, key) {_x000D_
    var criteria = {};_x000D_
    criteria[key] = null;_x000D_
    return _.map(arr1, function(item) {_x000D_
      criteria[key] = item[key];_x000D_
      return _.merge(item, _.find(arr2, criteria));_x000D_
    });_x000D_
  }_x000D_
});_x000D_
_x000D_
var arr1 = [{_x000D_
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d6")',_x000D_
  "bank": 'ObjectId("575b052ca6f66a5732749ecc")',_x000D_
  "country": 'ObjectId("575b0523a6f66a5732749ecb")'_x000D_
}, {_x000D_
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d8")',_x000D_
  "bank": 'ObjectId("575b052ca6f66a5732749ecc")',_x000D_
  "country": 'ObjectId("575b0523a6f66a5732749ecb")'_x000D_
}];_x000D_
_x000D_
var arr2 = [{_x000D_
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d8")',_x000D_
  "name": 'yyyyyyyyyy',_x000D_
  "age": 26_x000D_
}, {_x000D_
  "member": 'ObjectId("57989cbe54cf5d2ce83ff9d6")',_x000D_
  "name": 'xxxxxx',_x000D_
  "age": 25_x000D_
}];_x000D_
_x000D_
var arr3 = _.mergeByKey(arr1, arr2, 'member');_x000D_
_x000D_
document.body.innerHTML = JSON.stringify(arr3, null, 4);
_x000D_
body { font-family: monospace; white-space: pre; }
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.14.0/lodash.min.js"></script>
_x000D_
_x000D_
_x000D_

Running powershell script within python script, how to make python print the powershell output while it is running

  1. Make sure you can run powershell scripts (it is disabled by default). Likely you have already done this. http://technet.microsoft.com/en-us/library/ee176949.aspx

    Set-ExecutionPolicy RemoteSigned
    
  2. Run this python script on your powershell script helloworld.py:

    # -*- coding: iso-8859-1 -*-
    import subprocess, sys
    
    p = subprocess.Popen(["powershell.exe", 
                  "C:\\Users\\USER\\Desktop\\helloworld.ps1"], 
                  stdout=sys.stdout)
    p.communicate()
    

This code is based on python3.4 (or any 3.x series interpreter), though it should work on python2.x series as well.

C:\Users\MacEwin\Desktop>python helloworld.py
Hello World

CakePHP select default value in SELECT input

You should never use select(), or text(), or radio() etc.; it's terrible practice. You should use input():

$form->input('tree_id', array('options' => $trees));

Then in the controller:

$this->data['Leaf']['tree_id'] = $id;

Python creating a dictionary of lists

You can use defaultdict:

>>> from collections import defaultdict
>>> d = defaultdict(list)
>>> a = ['1', '2']
>>> for i in a:
...   for j in range(int(i), int(i) + 2):
...     d[j].append(i)
...
>>> d
defaultdict(<type 'list'>, {1: ['1'], 2: ['1', '2'], 3: ['2']})
>>> d.items()
[(1, ['1']), (2, ['1', '2']), (3, ['2'])]

AngularJS Dropdown required validation

You need to add a name attribute to your dropdown list, then you need to add a required attribute, and then you can reference the error using myForm.[input name].$error.required:

HTML:

        <form name="myForm" ng-controller="Ctrl" ng-submit="save(myForm)" novalidate>
        <input type="text" name="txtServiceName" ng-model="ServiceName" required>
<span ng-show="myForm.txtServiceName.$error.required">Enter Service Name</span>
<br/>
          <select name="service_id" class="Sitedropdown" style="width: 220px;"          
                  ng-model="ServiceID" 
                  ng-options="service.ServiceID as service.ServiceName for service in services"
                  required> 
            <option value="">Select Service</option> 
          </select> 
          <span ng-show="myForm.service_id.$error.required">Select service</span>

        </form>

    Controller:

        function Ctrl($scope) {
          $scope.services = [
            {ServiceID: 1, ServiceName: 'Service1'},
            {ServiceID: 2, ServiceName: 'Service2'},
            {ServiceID: 3, ServiceName: 'Service3'}
          ];

    $scope.save = function(myForm) {
    console.log('Selected Value: '+ myForm.service_id.$modelValue);
    alert('Data Saved! without validate');
    };
        }

Here's a working plunker.

How to install Android app on LG smart TV?

Thanks for the research FIRESTICK is a solution for non Android based but there's another one Im using if you guys want to try it let me know...

LG, VIZIO, SAMSUNG and PANASONIC TVs are not android based, and you cannot run APKs off of them... You should just buy a fire stick and call it a day. The only TVs that are android-based, and you can install APKs are: SONY, PHILIPS and SHARP, PHILCO and TOSHIBA.

How to query a MS-Access Table from MS-Excel (2010) using VBA

Option Explicit

Const ConnectionStrngAccessPW As String = _"Provider=Microsoft.ACE.OLEDB.12.0;
Data Source=C:\Users\BARON\Desktop\Test_DB-PW.accdb;
Jet OLEDB:Database Password=123pass;"

Const ConnectionStrngAccess As String = _"Provider=Microsoft.ACE.OLEDB.12.0;
Data Source=C:\Users\BARON\Desktop\Test_DB.accdb;
Persist Security Info=False;"

'C:\Users\BARON\Desktop\Test.accdb

Sub ModifyingExistingDataOnAccessDB()

    Dim TableConn As ADODB.Connection
    Dim TableData As ADODB.Recordset


    Set TableConn = New ADODB.Connection
    Set TableData = New ADODB.Recordset

    TableConn.ConnectionString = ConnectionStrngAccess

    TableConn.Open

On Error GoTo CloseConnection

    With TableData
        .ActiveConnection = TableConn
        '.Source = "SELECT Emp_Age FROM Roster WHERE Emp_Age > 40;"
        .Source = "Roster"
        .LockType = adLockOptimistic
        .CursorType = adOpenForwardOnly
        .Open
        On Error GoTo CloseRecordset

            Do Until .EOF
                If .Fields("Emp_Age").Value > 40 Then
                    .Fields("Emp_Age").Value = 40
                    .Update
                End If
                .MoveNext
            Loop
            .MoveFirst

        MsgBox "Update Complete"
    End With


CloseRecordset:
    TableData.CancelUpdate
    TableData.Close

CloseConnection:
    TableConn.Close

    Set TableConn = Nothing
    Set TableData = Nothing

End Sub

Sub AddingDataToAccessDB()

    Dim TableConn As ADODB.Connection
    Dim TableData As ADODB.Recordset
    Dim r As Range

    Set TableConn = New ADODB.Connection
    Set TableData = New ADODB.Recordset

    TableConn.ConnectionString = ConnectionStrngAccess

    TableConn.Open

On Error GoTo CloseConnection

    With TableData
        .ActiveConnection = TableConn
        .Source = "Roster"
        .LockType = adLockOptimistic
        .CursorType = adOpenForwardOnly
        .Open
        On Error GoTo CloseRecordset

        Sheet3.Activate
        For Each r In Range("B3", Range("B3").End(xlDown))

            MsgBox "Adding " & r.Offset(0, 1)
            .AddNew
            .Fields("Emp_ID").Value = r.Offset(0, 0).Value
            .Fields("Emp_Name").Value = r.Offset(0, 1).Value
            .Fields("Emp_DOB").Value = r.Offset(0, 2).Value
            .Fields("Emp_SOD").Value = r.Offset(0, 3).Value
            .Fields("Emp_EOD").Value = r.Offset(0, 4).Value
            .Fields("Emp_Age").Value = r.Offset(0, 5).Value
            .Fields("Emp_Gender").Value = r.Offset(0, 6).Value
            .Update

        Next r

        MsgBox "Update Complete"
    End With


CloseRecordset:
    TableData.Close

CloseConnection:
    TableConn.Close

    Set TableConn = Nothing
    Set TableData = Nothing

End Sub

Using .text() to retrieve only text not nested in child tags

This is an old question but the top answer is very inefficient. Here's a better solution:

$.fn.myText = function() {
    var str = '';

    this.contents().each(function() {
        if (this.nodeType == 3) {
            str += this.textContent || this.innerText || '';
        }
    });

    return str;
};

And just do this:

$("#foo").myText();

Replace Div with another Div

This should help you

HTML

<!-- pretty much i just need to click a link within the regions table and it changes to the neccesary div. -->

<table>
<tr class="thumb"></tr>
    <td><a href="#" class="showall">All Regions</a> (shows main map) (link)</td>   

<tr class="thumb"></tr>
<td>Northern Region (link)</td>
</tr>

<tr class="thumb"></tr>
<td>Southern Region (link)</td>
</tr>

<tr class="thumb"></tr>
<td>Eastern Region (link)</td>
</tr>
</table>
<br />

<div id="mainmapplace">
    <div id="mainmap">
        All Regions image
    </div>
</div>
<div id="region">
    <div class="replace">northern image</div>
    <div class="replace">southern image</div>
    <div class="replace">Eastern image</div>
</div>

JavaScript

var originalmap;
var flag = false;

$(function (){

    $(".replace").click(function(){
            flag = true;
            originalmap = $('#mainmap');
            $('#mainmap').replaceWith($(this));
        });

    $('.showall').click(
        function(){
            if(flag == true){
                $('#region').append($('#mainmapplace .replace'));                
                $('#mainmapplace').children().remove();
                $('#mainmapplace').append($(originalmap));
                //$('#mapplace').append();
            }
        }
    )

})

CSS

#mainmapplace{
    width: 100px;
    height: 100px;
    background: red;
}

#region div{
    width: 100px;
    height: 100px;
    background: blue;
    margin: 10px 0 0 0;
}

Pass multiple parameters to rest API - Spring

(1) Is it possible to pass a JSON object to the url like in Ex.2?

No, because http://localhost:8080/api/v1/mno/objectKey/{"id":1, "name":"Saif"} is not a valid URL.

If you want to do it the RESTful way, use http://localhost:8080/api/v1/mno/objectKey/1/Saif, and defined your method like this:

@RequestMapping(path = "/mno/objectKey/{id}/{name}", method = RequestMethod.GET)
public Book getBook(@PathVariable int id, @PathVariable String name) {
    // code here
}

(2) How can we pass and parse the parameters in Ex.1?

Just add two request parameters, and give the correct path.

@RequestMapping(path = "/mno/objectKey", method = RequestMethod.GET)
public Book getBook(@RequestParam int id, @RequestParam String name) {
    // code here
}

UPDATE (from comment)

What if we have a complicated parameter structure ?

"A": [ {
    "B": 37181,
    "timestamp": 1160100436,
    "categories": [ {
        "categoryID": 2653,
        "timestamp": 1158555774
    }, {
        "categoryID": 4453,
        "timestamp": 1158555774
    } ]
} ]

Send that as a POST with the JSON data in the request body, not in the URL, and specify a content type of application/json.

@RequestMapping(path = "/mno/objectKey", method = RequestMethod.POST, consumes = "application/json")
public Book getBook(@RequestBody ObjectKey objectKey) {
    // code here
}

Oracle SQL Developer spool output?

For Spooling in Oracle SQL Developer, here is the solution.

set heading on

set linesize 1500

set colsep '|'

set numformat 99999999999999999999

set pagesize 25000

spool E:\abc.txt

@E:\abc.sql;

spool off

The hint is :

  1. when we spool from sql plus , then the whole query is required.

  2. when we spool from Oracle Sql Developer , then the reference path of the query required as given in the specified example.

Getting pids from ps -ef |grep keyword

I use

ps -C "keyword" -o pid=

This command should give you a PID number.

Android - How to get application name? (Not package name)

In Kotlin, use the following codes to get Application Name:

        // Get App Name
        var appName: String = ""
        val applicationInfo = this.getApplicationInfo()
        val stringId = applicationInfo.labelRes
        if (stringId == 0) {
            appName = applicationInfo.nonLocalizedLabel.toString()
        }
        else {
            appName = this.getString(stringId)
        }

Set the location in iPhone Simulator

In my delegate callback, I check to see if I'm running in a simulator (#if TARGET_ IPHONE_SIMULATOR) and if so, I supply my own, pre-looked-up, Lat/Long. To my knowledge, there's no other way.

using wildcards in LDAP search filters/queries

This should work, at least according to the Search Filter Syntax article on MSDN network.

The "hang-up" you have noticed is probably just a delay. Try running the same query with narrower scope (for example the specific OU where the test object is located), as it may take very long time for processing if you run it against all AD objects.

You may also try separating the filter into two parts:

(|(displayName=*searchstring)(displayName=searchstring*))

How do I link a JavaScript file to a HTML file?

You can add script tags in your HTML document, ideally inside the which points to your javascript files. Order of the script tags are important. Load the jQuery before your script files if you want to use jQuery from your script.

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript" src="relative/path/to/your/javascript.js"></script>

Then in your javascript file you can refer to jQuery either using $ sign or jQuery. Example:

jQuery.each(arr, function(i) { console.log(i); }); 

Setting up Gradle for api 26 (Android)

Appart from setting maven source url to your gradle, I would suggest to add both design and appcompat libraries. Currently the latest version is 26.1.0

maven {
    url "https://maven.google.com"
}

...

compile 'com.android.support:appcompat-v7:26.1.0'
compile 'com.android.support:design:26.1.0'

Swift double to string

There are many answers here that suggest a variety of techniques. But when presenting numbers in the UI, you invariably want to use a NumberFormatter so that the results are properly formatted, rounded, and localized:

let value = 10000.5

let formatter = NumberFormatter()
formatter.numberStyle = .decimal

guard let string = formatter.string(for: value) else { return }
print(string) // 10,000.5

If you want fixed number of decimal places, e.g. for currency values

let value = 10000.5

let formatter = NumberFormatter()
formatter.numberStyle = .decimal
formatter.maximumFractionDigits = 2
formatter.minimumFractionDigits = 2

guard let string = formatter.string(for: value) else { return }
print(string) // 10,000.50

But the beauty of this approach, is that it will be properly localized, resulting in 10,000.50 in the US but 10.000,50 in Germany. Different locales have different preferred formats for numbers, and we should let NumberFormatter use the format preferred by the end user when presenting numeric values within the UI.

Needless to say, while NumberFormatter is essential when preparing string representations within the UI, it should not be used if writing numeric values as strings for persistent storage, interface with web services, etc.

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

Here you've got a copy-paste code:

class NameToBackgroundConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if(value.ToString() == "System")
            {
                return new SolidColorBrush(System.Windows.Media.Colors.Aqua);
            }else
            {
                return new SolidColorBrush(System.Windows.Media.Colors.Blue);
            }
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return null;
        }
    }

How to send a html email with the bash command "sendmail"?

The following works:

(
echo "From: ${from}";
echo "To: ${to}";
echo "Subject: ${subject}";
echo "Content-Type: text/html";
echo "MIME-Version: 1.0";
echo "";
echo "${message}";
) | sendmail -t

For troubleshooting msmtp, which is compatible with sendmail, see:

How to trim a file extension from a String in JavaScript?

Here's another regex-based solution:

filename.replace(/\.[^.$]+$/, '');

This should only chop off the last segment.

Kubernetes how to make Deployment to update image

Another option which is more suitable for debugging but worth mentioning is to check in revision history of your rollout:

$ kubectl rollout history deployment my-dep
deployment.apps/my-dep
 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

To see the details of each revision, run:

 kubectl rollout history deployment my-dep --revision=2

And then returning to the previous revision by running:

 $kubectl rollout undo deployment my-dep --to-revision=2

And then returning back to the new one.
Like running ctrl+z -> ctrl+y (:

(*) The CHANGE-CAUSE is <none> because you should run the updates with the --record flag - like mentioned here:

kubectl set image deployment/nginx-deployment nginx=nginx:1.16.1 --record

(**) There is a discussion regarding deprecating this flag.

hadoop No FileSystem for scheme: file

This is not related to Flink, but I've found this issue in Flink also.

For people using Flink, you need to download Pre-bundled Hadoop and put it inside /opt/flink/lib.

Rearrange columns using cut

You may also combine cut and paste:

paste <(cut -f2 file.txt) <(cut -f1 file.txt)

via comments: It's possible to avoid bashisms and remove one instance of cut by doing:

paste file.txt file.txt | cut -f2,3

How do I hide certain files from the sidebar in Visual Studio Code?

The __pycache__ folder and *.pyc files are totally unnecessary to the developer. To hide these files from the explorer view, we need to edit the settings.json for VSCode. Add the folder and the files as shown below:

"files.exclude": {
  ...
  ...
  "**/*.pyc": {"when": "$(basename).py"}, 
  "**/__pycache__": true,
  ...
  ...
}

Ansible - Save registered variable to file

---
- hosts: all
  tasks:
  - name: Gather Version
    debug:
     msg: "The server Operating system is {{ ansible_distribution }} {{ ansible_distribution_major_version }}"
  - name: Write  Version
    local_action: shell echo "This is  {{ ansible_distribution }} {{ ansible_distribution_major_version }}" >> /tmp/output

How can a windows service programmatically restart itself?

I don't think it can. When a service is "stopped", it gets totally unloaded.

Well, OK, there's always a way I suppose. For instance, you could create a detached process to stop the service, then restart it, then exit.

How do I delete everything below row X in VBA/Excel?

It sounds like something like the below will suit your needs:

With Sheets("Sheet1")
    .Rows( X & ":" & .Rows.Count).Delete
End With

Where X is a variable that = the row number ( 415 )

C# Java HashMap equivalent

Dictionary is probably the closest. System.Collections.Generic.Dictionary implements the System.Collections.Generic.IDictionary interface (which is similar to Java's Map interface).

Some notable differences that you should be aware of:

  • Adding/Getting items
    • Java's HashMap has the put and get methods for setting/getting items
      • myMap.put(key, value)
      • MyObject value = myMap.get(key)
    • C#'s Dictionary uses [] indexing for setting/getting items
      • myDictionary[key] = value
      • MyObject value = myDictionary[key]
  • null keys
    • Java's HashMap allows null keys
    • .NET's Dictionary throws an ArgumentNullException if you try to add a null key
  • Adding a duplicate key
    • Java's HashMap will replace the existing value with the new one.
    • .NET's Dictionary will replace the existing value with the new one if you use [] indexing. If you use the Add method, it will instead throw an ArgumentException.
  • Attempting to get a non-existent key
    • Java's HashMap will return null.
    • .NET's Dictionary will throw a KeyNotFoundException. You can use the TryGetValue method instead of the [] indexing to avoid this:
      MyObject value = null; if (!myDictionary.TryGetValue(key, out value)) { /* key doesn't exist */ }

Dictionary's has a ContainsKey method that can help deal with the previous two problems.

How to change sa password in SQL Server 2008 express?

I didn't know the existing sa password so this is what I did:

  1. Open Services in Control Panel

  2. Find the "SQL Server (SQLEXPRESS)" entry and select properties

  3. Stop the service

  4. Enter "-m" at the beginning of the "Start parameters" fields. If there are other parameters there already add a semi-colon after -m;

  5. Start the service

  6. Open a Command Prompt

Enter the command:

osql -S YourPcName\SQLEXPRESS -E

(change YourPcName to whatever your PC is called).

  1. At the prompt type the following commands:
alter login sa enable
go
sp_password NULL,'new_password','sa'
go
quit
  1. Stop the "SQL Server (SQLEXPRESS)" service

  2. Remove the "-m" from the Start parameters field

  3. Start the service

How to determine CPU and memory consumption from inside a process?

Linux

In Linux, this information is available in the /proc file system. I'm not a big fan of the text file format used, as each Linux distribution seems to customize at least one important file. A quick look as the source to 'ps' reveals the mess.

But here is where to find the information you seek:

/proc/meminfo contains the majority of the system-wide information you seek. Here it looks like on my system; I think you are interested in MemTotal, MemFree, SwapTotal, and SwapFree:

Anderson cxc # more /proc/meminfo
MemTotal:      4083948 kB
MemFree:       2198520 kB
Buffers:         82080 kB
Cached:        1141460 kB
SwapCached:          0 kB
Active:        1137960 kB
Inactive:       608588 kB
HighTotal:     3276672 kB
HighFree:      1607744 kB
LowTotal:       807276 kB
LowFree:        590776 kB
SwapTotal:     2096440 kB
SwapFree:      2096440 kB
Dirty:              32 kB
Writeback:           0 kB
AnonPages:      523252 kB
Mapped:          93560 kB
Slab:            52880 kB
SReclaimable:    24652 kB
SUnreclaim:      28228 kB
PageTables:       2284 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:   4138412 kB
Committed_AS:  1845072 kB
VmallocTotal:   118776 kB
VmallocUsed:      3964 kB
VmallocChunk:   112860 kB
HugePages_Total:     0
HugePages_Free:      0
HugePages_Rsvd:      0
Hugepagesize:     2048 kB

For CPU utilization, you have to do a little work. Linux makes available overall CPU utilization since system start; this probably isn't what you are interested in. If you want to know what the CPU utilization was for the last second, or 10 seconds, then you need to query the information and calculate it yourself.

The information is available in /proc/stat, which is documented pretty well at http://www.linuxhowtos.org/System/procstat.htm; here is what it looks like on my 4-core box:

Anderson cxc #  more /proc/stat
cpu  2329889 0 2364567 1063530460 9034 9463 96111 0
cpu0 572526 0 636532 265864398 2928 1621 6899 0
cpu1 590441 0 531079 265949732 4763 351 8522 0
cpu2 562983 0 645163 265796890 682 7490 71650 0
cpu3 603938 0 551790 265919440 660 0 9040 0
intr 37124247
ctxt 50795173133
btime 1218807985
processes 116889
procs_running 1
procs_blocked 0

First, you need to determine how many CPUs (or processors, or processing cores) are available in the system. To do this, count the number of 'cpuN' entries, where N starts at 0 and increments. Don't count the 'cpu' line, which is a combination of the cpuN lines. In my example, you can see cpu0 through cpu3, for a total of 4 processors. From now on, you can ignore cpu0..cpu3, and focus only on the 'cpu' line.

Next, you need to know that the fourth number in these lines is a measure of idle time, and thus the fourth number on the 'cpu' line is the total idle time for all processors since boot time. This time is measured in Linux "jiffies", which are 1/100 of a second each.

But you don't care about the total idle time; you care about the idle time in a given period, e.g., the last second. Do calculate that, you need to read this file twice, 1 second apart.Then you can do a diff of the fourth value of the line. For example, if you take a sample and get:

cpu  2330047 0 2365006 1063853632 9035 9463 96114 0

Then one second later you get this sample:

cpu  2330047 0 2365007 1063854028 9035 9463 96114 0

Subtract the two numbers, and you get a diff of 396, which means that your CPU had been idle for 3.96 seconds out of the last 1.00 second. The trick, of course, is that you need to divide by the number of processors. 3.96 / 4 = 0.99, and there is your idle percentage; 99% idle, and 1% busy.

In my code, I have a ring buffer of 360 entries, and I read this file every second. That lets me quickly calculate the CPU utilization for 1 second, 10 seconds, etc., all the way up to 1 hour.

For the process-specific information, you have to look in /proc/pid; if you don't care abut your pid, you can look in /proc/self.

CPU used by your process is available in /proc/self/stat. This is an odd-looking file consisting of a single line; for example:

19340 (whatever) S 19115 19115 3084 34816 19115 4202752 118200 607 0 0 770 384 2
 7 20 0 77 0 266764385 692477952 105074 4294967295 134512640 146462952 321468364
8 3214683328 4294960144 0 2147221247 268439552 1276 4294967295 0 0 17 0 0 0 0

The important data here are the 13th and 14th tokens (0 and 770 here). The 13th token is the number of jiffies that the process has executed in user mode, and the 14th is the number of jiffies that the process has executed in kernel mode. Add the two together, and you have its total CPU utilization.

Again, you will have to sample this file periodically, and calculate the diff, in order to determine the process's CPU usage over time.

Edit: remember that when you calculate your process's CPU utilization, you have to take into account 1) the number of threads in your process, and 2) the number of processors in the system. For example, if your single-threaded process is using only 25% of the CPU, that could be good or bad. Good on a single-processor system, but bad on a 4-processor system; this means that your process is running constantly, and using 100% of the CPU cycles available to it.

For the process-specific memory information, you ahve to look at /proc/self/status, which looks like this:

Name:   whatever
State:  S (sleeping)
Tgid:   19340
Pid:    19340
PPid:   19115
TracerPid:      0
Uid:    0       0       0       0
Gid:    0       0       0       0
FDSize: 256
Groups: 0 1 2 3 4 6 10 11 20 26 27
VmPeak:   676252 kB
VmSize:   651352 kB
VmLck:         0 kB
VmHWM:    420300 kB
VmRSS:    420296 kB
VmData:   581028 kB
VmStk:       112 kB
VmExe:     11672 kB
VmLib:     76608 kB
VmPTE:      1244 kB
Threads:        77
SigQ:   0/36864
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: fffffffe7ffbfeff
SigIgn: 0000000010001000
SigCgt: 20000001800004fc
CapInh: 0000000000000000
CapPrm: 00000000ffffffff
CapEff: 00000000fffffeff
Cpus_allowed:   0f
Mems_allowed:   1
voluntary_ctxt_switches:        6518
nonvoluntary_ctxt_switches:     6598

The entries that start with 'Vm' are the interesting ones:

  • VmPeak is the maximum virtual memory space used by the process, in kB (1024 bytes).
  • VmSize is the current virtual memory space used by the process, in kB. In my example, it's pretty large: 651,352 kB, or about 636 megabytes.
  • VmRss is the amount of memory that have been mapped into the process' address space, or its resident set size. This is substantially smaller (420,296 kB, or about 410 megabytes). The difference: my program has mapped 636 MB via mmap(), but has only accessed 410 MB of it, and thus only 410 MB of pages have been assigned to it.

The only item I'm not sure about is Swapspace currently used by my process. I don't know if this is available.

How to add SHA-1 to android application

MacOS just paste in the Terminal:

keytool -list -v -alias androiddebugkey -keystore ~/.android/debug.keystore -storepass android -keypass android

How much data can a List can hold at the maximum?

It depends on the List implementation. Since you index arrays with ints, an ArrayList can't hold more than Integer.MAX_VALUE elements. A LinkedList isn't limited in the same way, though, and can contain any amount of elements.

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

Go through C:\apache-tomcat-7.0.47\lib path (this path may be differ based on where you installed the Tomcat server) then past ojdbc14.jar if its not contain.

Then restart the server in eclipse then run your app on server

Get Public URL for File - Google Cloud Storage - App Engine (Python)

You need to use get_serving_url from the Images API. As that page explains, you need to call create_gs_key() first to get the key to pass to the Images API.

jQuery - how can I find the element with a certain id?

As all html ids are unique in a valid html document why not search for the ID directly? If you're concerned if they type in an id that isn't a table then you can inspect the tag type that way?

Just an idea!

S

Making heatmap from pandas DataFrame

If you don't need a plot per say, and you're simply interested in adding color to represent the values in a table format, you can use the style.background_gradient() method of the pandas data frame. This method colorizes the HTML table that is displayed when viewing pandas data frames in e.g. the JupyterLab Notebook and the result is similar to using "conditional formatting" in spreadsheet software:

import numpy as np 
import pandas as pd


index= ['aaa', 'bbb', 'ccc', 'ddd', 'eee']
cols = ['A', 'B', 'C', 'D']
df = pd.DataFrame(abs(np.random.randn(5, 4)), index=index, columns=cols)
df.style.background_gradient(cmap='Blues')

enter image description here

For detailed usage, please see the more elaborate answer I provided on the same topic previously and the styling section of the pandas documentation.