Programs & Examples On #Phpt

PHPT scripts are unit and integration tests for the PHP interpreter and user applications.

set value of input field by php variable's value

inside the Form, You can use this code. Replace your variable name (i use $variable)

<input type="text" value="<?php echo (isset($variable))?$variable:'';?>">

Apache: The requested URL / was not found on this server. Apache

Try changing Deny from all to Allow from all in your conf and see if that helps.

How to replace url parameter with javascript/jquery?

Javascript now give a very useful functionnality to handle url parameters: URLSearchParams

var searchParams = new URLSearchParams(window.location.search);
searchParams.set('src','newSrc')
var newParams = searchParams.toString()

PHP returning JSON to JQUERY AJAX CALL

You can return json in PHP this way:

header('Content-Type: application/json');
echo json_encode(array('foo' => 'bar'));
exit;

How to select an option from drop down using Selenium WebDriver C#?

To Select an Option Via Text;

(new SelectElement(driver.FindElement(By.XPath(""))).SelectByText("");

To Select an Option via Value:

 (new SelectElement(driver.FindElement(By.XPath(""))).SelectByValue("");

What's the best way to select the minimum value from several columns?

You could also do this with a union query. As the number of columns increase, you would need to modify the query, but at least it would be a straight forward modification.

Select T.Id, T.Col1, T.Col2, T.Col3, A.TheMin
From   YourTable T
       Inner Join (
         Select A.Id, Min(A.Col1) As TheMin
         From   (
                Select Id, Col1
                From   YourTable

                Union All

                Select Id, Col2
                From   YourTable

                Union All

                Select Id, Col3
                From   YourTable
                ) As A
         Group By A.Id
       ) As A
       On T.Id = A.Id

How can I backup a remote SQL Server database to a local drive?

I'm astonished that no-one has mentioned the scripted backup solution offered by Ola Hallengren which absolutely does allow you to backup a DB from a remote server to a UNC path on your network for free (I'm actually using it as I type to backup a DB from a dev server to which I have no remote access other than through SSMS to a share on my dev PC). This has been available since 2008 and works on SQL Server 2005 through to 2014.

You need to ensure that the share you set up has enough access: I tend to allow full read/write to the 'Everyone' AD group for the duration of the backup process because I'm too lazy to figure out anything more restrictive but that's personal choice.

It's well-used, well-documented and very flexible. I tend to put the procs and the logging table in their own little utility database and then fire it up. Provided everything is in your AD domain and not remote in the sense that it's out on a co-located server or something, this works very well.

Apologies for adding to a very old thread but I came across this when looking for something else and figured it was a worthwhile addition for anyone looking for this topic.

How to remove underline from a name on hover

Remove the text decoration for the anchor tag

<a name="Section 1" style="text-decoration : none">Section</a>

C# nullable string error

System.String is a reference type and already "nullable".

Nullable<T> and the ? suffix are for value types such as Int32, Double, DateTime, etc.

Count the frequency that a value occurs in a dataframe column

df.category.value_counts()

This short little line of code will give you the output you want.

If your column name has spaces you can use

df['category'].value_counts()

ClassCastException, casting Integer to Double

We can cast an int to a double but we can't do the same with the wrapper classes Integer and Double:

 int     a = 1;
 Integer b = 1;   // inboxing, requires Java 1.5+

 double  c = (double) a;   // OK
 Double  d = (Double) b;   // No way.

This shows the compile time error that corresponds to your runtime exception.

Check if user is using IE

This only work below IE 11 version.

var ie_version = parseInt(window.navigator.userAgent.substring(window.navigator.userAgent.indexOf("MSIE ") + 5, window.navigator.userAgent.indexOf(".", window.navigator.userAgent.indexOf("MSIE "))));

console.log("version number",ie_version);

How to assign an exec result to a sql variable?

I always use the return value to pass back error status. If you need to pass back one value I'd use an output parameter.

sample stored procedure, with an OUTPUT parameter:

CREATE PROCEDURE YourStoredProcedure 
(
    @Param1    int
   ,@Param2    varchar(5)
   ,@Param3    datetime OUTPUT
)
AS
IF ISNULL(@Param1,0)>5
BEGIN
    SET @Param3=GETDATE()
END
ELSE
BEGIN
    SET @Param3='1/1/2010'
END
RETURN 0
GO

call to the stored procedure, with an OUTPUT parameter:

DECLARE @OutputParameter  datetime
       ,@ReturnValue      int

EXEC @ReturnValue=YourStoredProcedure 1,null, @OutputParameter OUTPUT
PRINT @ReturnValue
PRINT CONVERT(char(23),@OutputParameter ,121)

OUTPUT:

0
2010-01-01 00:00:00.000

Angular2: How to load data before rendering the component?

update

original

When console.log(this.ev) is executed after this.fetchEvent();, this doesn't mean the fetchEvent() call is done, this only means that it is scheduled. When console.log(this.ev) is executed, the call to the server is not even made and of course has not yet returned a value.

Change fetchEvent() to return a Promise

     fetchEvent(){
        return  this._apiService.get.event(this.eventId).then(event => {
            this.ev = event;
            console.log(event); // Has a value
            console.log(this.ev); // Has a value
        });
     }

change ngOnInit() to wait for the Promise to complete

    ngOnInit() {
        this.fetchEvent().then(() =>
        console.log(this.ev)); // Now has value;
    }

This actually won't buy you much for your use case.

My suggestion: Wrap your entire template in an <div *ngIf="isDataAvailable"> (template content) </div>

and in ngOnInit()

    isDataAvailable:boolean = false;

    ngOnInit() {
        this.fetchEvent().then(() =>
        this.isDataAvailable = true); // Now has value;
    }

How to specify a port to run a create-react-app based project?

Changing in my package.json file "start": "export PORT=3001 && react-scripts start" worked for me too and I'm on macOS 10.13.4

Converting UTF-8 to ISO-8859-1 in Java - how to keep it as single byte

evict non ISO-8859-1 characters, will be replace by '?' (before send to a ISO-8859-1 DB by example):

utf8String = new String ( utf8String.getBytes(), "ISO-8859-1" );

How to select/get drop down option in Selenium 2

driver.findElement(By.id("id_dropdown_menu")).click();
driver.findElement(By.xpath("xpath_from_seleniumIDE")).click();

good luck

Store multiple values in single key in json

{
  "number" : ["1","2","3"],
  "alphabet" : ["a", "b", "c"]
}

LINQ - Full Outer Join

I've written this extensions class for an app perhaps 6 years ago, and have been using it ever since in many solutions without issues. Hope it helps.

edit: I noticed some might not know how to use an extension class.

To use this extension class, just reference its namespace in your class by adding the following line using joinext;

^ this should allow you to to see the intellisense of extension functions on any IEnumerable object collection you happen to use.

Hope this helps. Let me know if it's still not clear, and I'll hopefully write a sample example on how to use it.

Now here is the class:

namespace joinext
{    
public static class JoinExtensions
    {
        public static IEnumerable<TResult> FullOuterJoin<TOuter, TInner, TKey, TResult>(
            this IEnumerable<TOuter> outer,
            IEnumerable<TInner> inner,
            Func<TOuter, TKey> outerKeySelector,
            Func<TInner, TKey> innerKeySelector,
            Func<TOuter, TInner, TResult> resultSelector)
            where TInner : class
            where TOuter : class
        {
            var innerLookup = inner.ToLookup(innerKeySelector);
            var outerLookup = outer.ToLookup(outerKeySelector);

            var innerJoinItems = inner
                .Where(innerItem => !outerLookup.Contains(innerKeySelector(innerItem)))
                .Select(innerItem => resultSelector(null, innerItem));

            return outer
                .SelectMany(outerItem =>
                {
                    var innerItems = innerLookup[outerKeySelector(outerItem)];

                    return innerItems.Any() ? innerItems : new TInner[] { null };
                }, resultSelector)
                .Concat(innerJoinItems);
        }


        public static IEnumerable<TResult> LeftJoin<TOuter, TInner, TKey, TResult>(
            this IEnumerable<TOuter> outer,
            IEnumerable<TInner> inner,
            Func<TOuter, TKey> outerKeySelector,
            Func<TInner, TKey> innerKeySelector,
            Func<TOuter, TInner, TResult> resultSelector)
        {
            return outer.GroupJoin(
                inner,
                outerKeySelector,
                innerKeySelector,
                (o, i) =>
                    new { o = o, i = i.DefaultIfEmpty() })
                    .SelectMany(m => m.i.Select(inn =>
                        resultSelector(m.o, inn)
                        ));

        }



        public static IEnumerable<TResult> RightJoin<TOuter, TInner, TKey, TResult>(
            this IEnumerable<TOuter> outer,
            IEnumerable<TInner> inner,
            Func<TOuter, TKey> outerKeySelector,
            Func<TInner, TKey> innerKeySelector,
            Func<TOuter, TInner, TResult> resultSelector)
        {
            return inner.GroupJoin(
                outer,
                innerKeySelector,
                outerKeySelector,
                (i, o) =>
                    new { i = i, o = o.DefaultIfEmpty() })
                    .SelectMany(m => m.o.Select(outt =>
                        resultSelector(outt, m.i)
                        ));

        }

    }
}

Plotting two variables as lines using ggplot2 on the same graph

Using your data:

test_data <- data.frame(
var0 = 100 + c(0, cumsum(runif(49, -20, 20))),
var1 = 150 + c(0, cumsum(runif(49, -10, 10))),
Dates = seq.Date(as.Date("2002-01-01"), by="1 month", length.out=100))

I create a stacked version which is what ggplot() would like to work with:

stacked <- with(test_data,
                data.frame(value = c(var0, var1),
                           variable = factor(rep(c("Var0","Var1"),
                                                 each = NROW(test_data))),
                           Dates = rep(Dates, 2)))

In this case producing stacked was quite easy as we only had to do a couple of manipulations, but reshape() and the reshape and reshape2 might be useful if you have a more complex real data set to manipulate.

Once the data are in this stacked form, it only requires a simple ggplot() call to produce the plot you wanted with all the extras (one reason why higher-level plotting packages like lattice and ggplot2 are so useful):

require(ggplot2)
p <- ggplot(stacked, aes(Dates, value, colour = variable))
p + geom_line()

I'll leave it to you to tidy up the axis labels, legend title etc.

HTH

Laravel 5 - artisan seed [ReflectionException] Class SongsTableSeeder does not exist

If you have copied the seeders files from any other project then you need to run the artisan command php artisan db:seed otherwise it is fine.

Javascript: Easier way to format numbers?

No, there is no built-in support for number formatting, but googling will turn up loads of code snippets that will do this for you.

EDIT: I missed the last sentence of your post. Try http://code.google.com/p/jquery-utils/wiki/StringFormat for a jQuery solution.

How to read all files in a folder from Java?

All of the answers on this topic that make use of the new Java 8 functions are neglecting to close the stream. The example in the accepted answer should be:

try (Stream<Path> filePathStream=Files.walk(Paths.get("/home/you/Desktop"))) {
    filePathStream.forEach(filePath -> {
        if (Files.isRegularFile(filePath)) {
            System.out.println(filePath);
        }
    });
}

From the javadoc of the Files.walk method:

The returned stream encapsulates one or more DirectoryStreams. If timely disposal of file system resources is required, the try-with-resources construct should be used to ensure that the stream's close method is invoked after the stream operations are completed.

How does Go update third-party packages?

The above answeres have the following problems:

  1. They update everything including your app (in case you have uncommitted changes).
  2. They updated packages you may have already removed from your project but are already on your disk.

To avoid these, do the following:

  1. Delete the 3rd party folders that you want to update.
  2. go to your app folder and run go get -d

How do I create a master branch in a bare Git repository?

A branch is just a reference to a commit. Until you commit anything to the repository, you don't have any branches. You can see this in a non-bare repository as well.

$ mkdir repo
$ cd repo
$ git init
Initialized empty Git repository in /home/me/repo/.git/
$ git branch
$ touch foo
$ git add foo
$ git commit -m "new file"
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 foo
$ git branch
* master

How do I change select2 box height

You don't need to change the height for all select2 - source <input> classes are being copied to select2-container, so you can style them by classes of inputs. For example if you want to style the height of some instances of select2, add class your-class to source <select> element and then use ".select2-container.your-class in your CSS file.

Regards.

There is some issue: classes name as select2* are not copied.

Can I get "&&" or "-and" to work in PowerShell?

Use:

if (start-process filename1.exe) {} else {start-process filename2.exe}

It's a little longer than "&&", but it accomplishes the same thing without scripting and is not too hard to remember.

Test if a variable is a list or tuple

Not the most elegant, but I do (for Python 3):

if hasattr(instance, '__iter__') and not isinstance(instance, (str, bytes)):
    ...

This allows other iterables (like Django querysets) but excludes strings and bytestrings. I typically use this in functions that accept either a single object ID or a list of object IDs. Sometimes the object IDs can be strings and I don't want to iterate over those character by character. :)

"Unable to acquire application service" error while launching Eclipse

This error happen cause you deleted the config.ini file while you deleted the plugins. So, when it can not find configuration in config.ini when eclipse lauching, then it use default configuration which is not fit with your os. The following steps solve you problem:

  1. Delete setting in configuration folder.

  2. create a new config.ini file.

  3. copy following setting and save:

  4. osgi.splashPath = platform:/base/plugins/org.eclipse.platform  
    osgi.bundles=org.eclipse.equinox.common@2:start, org.eclipse.update.configurator@3:start, org.eclipse.core.runtime@start  
    eclipse.product=org.eclipse.sdk.ide  
    [email protected]/workspace  
    eof=eof  
    
  5. restart eclipse.

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

Here's a working example:

<div class="item item-text-wrap" ng-repeat="(key,value) in form_list">
  <b>{{key}}</b> : {{value}}
</div>

edited

How are parameters sent in an HTTP POST request?

First of all, let's differentiate between GET and POST

Get: It is the default HTTP request that is made to the server and is used to retrieve the data from the server and query string that comes after ? in a URI is used to retrieve a unique resource.

this is the format

GET /someweb.asp?data=value HTTP/1.0

here data=value is the query string value passed.

POST: It is used to send data to the server safely so anything that is needed, this is the format of a POST request

POST /somweb.aspHTTP/1.0
Host: localhost
Content-Type: application/x-www-form-urlencoded //you can put any format here
Content-Length: 11 //it depends
Name= somename

Why POST over GET?

In GET the value being sent to the servers are usually appended to the base URL in the query string,now there are 2 consequences of this

  • The GET requests are saved in browser history with the parameters. So your passwords remain un-encrypted in browser history. This was a real issue for Facebook back in the days.
  • Usually servers have a limit on how long a URI can be. If have too many parameters being sent you might receive 414 Error - URI too long

In case of post request your data from the fields are added to the body instead. Length of request params is calculated, and added to the header for content-length and no important data is directly appended to the URL.

You can use the Google Developer Tools' network section to see basic information about how requests are made to the servers.

and you can always add more values in your Request Headers like Cache-Control , Origin , Accept.

VBA array sort function?

I wonder what would you say about this array sorting code. It's quick for implementation and does the job ... haven't tested for large arrays yet. It works for one-dimensional arrays, for multidimensional additional values re-location matrix would need to be build (with one less dimension that the initial array).

       For AR1 = LBound(eArray, 1) To UBound(eArray, 1)
            eValue = eArray(AR1)
            For AR2 = LBound(eArray, 1) To UBound(eArray, 1)
                If eArray(AR2) < eValue Then
                    eArray(AR1) = eArray(AR2)
                    eArray(AR2) = eValue
                    eValue = eArray(AR1)
                End If
            Next AR2
        Next AR1

Get records of current month

Try this query:

SELECT *
FROM table 
WHERE MONTH(FROM_UNIXTIME(columnName))= MONTH(CURDATE())

Sublime Text 2: How do I change the color that the row number is highlighted?

tmtheme-editor.herokuapp.com seems pretty nice.

On the mac, the default theme files are in ~/Library/Application\ Support/Sublime\ Text\ 2/Packages/Color\ Scheme\ -\ Default

On Win7, the default theme files are in %appdata%\Sublime Text 2\Packages\Color Scheme - Default

Yahoo Finance API

IMHO the best place to find this information is: http://code.google.com/p/yahoo-finance-managed/

I used to use the "gummy-stuff" too but then I found this page which is far more organized and full of easy to use examples. I am using it now to get the data in CSV files and use the files in my C++/Qt project.

Inserting multiple rows in mysql

If you have your data in a text-file, you can use LOAD DATA INFILE.

When loading a table from a text file, use LOAD DATA INFILE. This is usually 20 times faster than using INSERT statements.

Optimizing INSERT Statements

You can find more tips on how to speed up your insert statements on the link above.

Open source face recognition for Android

macgyver offers face detection programs via a simple to use API.

The program below takes a reference to a public image and will return an array of the coordinates and dimensions of any faces detected in the image.

https://askmacgyver.com/explore/program/face-location/5w8J9u4z

Download and open PDF file using Ajax

What worked for me is the following code, as the server function is retrieving File(memoryStream.GetBuffer(), "application/pdf", "fileName.pdf");:

$http.get( fullUrl, { responseType: 'arraybuffer' })
            .success(function (response) {
                var blob = new Blob([response], { type: 'application/pdf' });

                if (window.navigator && window.navigator.msSaveOrOpenBlob) {
                    window.navigator.msSaveOrOpenBlob(blob); // for IE
                }
                else {
                    var fileURL = URL.createObjectURL(blob);
                    var newWin = window.open(fileURL);
                    newWin.focus();
                    newWin.reload();
                }
});

Free Barcode API for .NET

Could the Barcode Rendering Framework at Codeplex GitHub be of help?

How to output a multiline string in Bash?

Since I recommended printf in a comment, I should probably give some examples of its usage (although for printing a usage message, I'd be more likely to use Dennis' or Chris' answers). printf is a bit more complex to use than echo. Its first argument is a format string, in which escapes (like \n) are always interpreted; it can also contain format directives starting with %, which control where and how any additional arguments are included in it. Here are two different approaches to using it for a usage message:

First, you could include the entire message in the format string:

printf "usage: up [--level <n>| -n <levels>][--help][--version]\n\nReport bugs to: \nup home page: \n"

Note that unlike echo, you must include the final newline explicitly. Also, if the message happens to contain any % characters, they would have to be written as %%. If you wanted to include the bugreport and homepage addresses, they can be added quite naturally:

printf "usage: up [--level <n>| -n <levels>][--help][--version]\n\nReport bugs to: %s\nup home page: %s\n" "$bugreport" "$homepage"

Second, you could just use the format string to make it print each additional argument on a separate line:

printf "%s\n" "usage: up [--level <n>| -n <levels>][--help][--version]" "" "Report bugs to: " "up home page: "

With this option, adding the bugreport and homepage addresses is fairly obvious:

printf "%s\n" "usage: up [--level <n>| -n <levels>][--help][--version]" "" "Report bugs to: $bugreport" "up home page: $homepage"

Disable sorting on last column when using jQuery DataTables

Use this:

$(document).ready(function () {
            $('#workPatternDataTable').dataTable({
                //"aaSorting": [],
                ajax: null,
                columnDefs: [
                    {
                        targets: 0,
                        sortable: false,
                        autoWidth: false,
                    }
                ]
            });
        });

Rename package in Android Studio

I found another way that works or an extra step to some of the answers here especially if you want to change the domain as well. It works in Android Studio 1.4. This is what I did:

  1. Open Manifest.xml and change the package name to what you want.
  2. Open your app build.gradle file and change the Application Id in defaultConfig to the same name as in manifest and rebuild the project.
  3. If still an issue, open a file under the package name, go to the package breadcrumbs (i.e. package declaration at head of file) and set your cursor to the domain you want to change and hit "Shift + F6", it would come out with a dialog with multiple use warnings, click on "Rename packages" and then click on "Do Refactor" it should rename everything including the R.Java files.

So for example if you want to rename "com.example.app" to "com.YourDomain.app", open a file under the package to be renamed, in the package breadcrumbs, set your cursor to "example" part of the domain and hit Shift + F6 and rename package to "YourDomain".

Testing if value is a function

Make sure you are calling typeof on the actual function, not a string literal:

function x() { 
    console.log("hi"); 
}

typeof "x"; // returns "string"

typeof x; // returns "function"

Checking if float is an integer

stdlib float modf (float x, float *ipart) splits into two parts, check if return value (fractional part) == 0.

How to get the real and total length of char * (char array)?

when new allocates an array, depending on the compiler (i use gnu c++), the word in front of the array contains information about the number of bytes allocated.

The test code:

#include <stdio.h>
#include <stdlib.h>

int
main ()
{
    int arraySz;
    char *a;
    unsigned int *q;

    for (arraySz = 5; arraySz <= 64; arraySz++) {

        printf ("%02d - ", arraySz);

        a = new char[arraySz];
        unsigned char *p = (unsigned char *) a;

        q = (unsigned int *) (a - 4);
        printf ("%02d\n", (*q));

        delete[] (a);

    }
}

on my machine dumps out:

05 - 19
06 - 19
07 - 19
08 - 19
09 - 19
10 - 19
11 - 19
12 - 19
13 - 27
14 - 27
15 - 27
16 - 27
17 - 27
18 - 27
19 - 27
20 - 27
21 - 35
22 - 35
23 - 35
24 - 35
25 - 35
26 - 35
27 - 35
28 - 35
29 - 43
30 - 43
31 - 43
32 - 43
33 - 43
34 - 43
35 - 43
36 - 43
37 - 51
38 - 51
39 - 51
40 - 51
41 - 51
42 - 51
43 - 51
44 - 51
45 - 59
46 - 59
47 - 59
48 - 59
49 - 59
50 - 59
51 - 59
52 - 59
53 - 67
54 - 67
55 - 67
56 - 67
57 - 67
58 - 67
59 - 67
60 - 67
61 - 75
62 - 75
63 - 75
64 - 75

I would not recommend this solution (vector is better), but if you are really desperate, you could find a relationship and be able to conclude the number of bytes allocated from the heap.

Convert a secure string to plain text

In PS 7, you can use ConvertFrom-SecureString and -AsPlainText:

 $UnsecurePassword = ConvertFrom-SecureString -SecureString $SecurePassword -AsPlainText

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.security/ConvertFrom-SecureString?view=powershell-7#parameters

ConvertFrom-SecureString
           [-SecureString] <SecureString>
           [-AsPlainText]
           [<CommonParameters>]

React.createElement: type is invalid -- expected a string

It's quite simple, really. I got this issue when I started coding React, and the problem is almost always because the import:

import React, { memo } from 'react';

You can use destructuring this because react lib has a property as memo, but you can not destructuring something like this

import { user } from 'assets/images/icons/Profile.svg';

because it's not a object.

Hope it helps!

How to embed a PDF viewer in a page?

pdf2htmlEX by coolwanglu is probably the best solution out there to convert a pdf file into html. You could do a simple convert and then embed the html page as an iframe or something similar.

How to bring an activity to foreground (top of stack)?

Here is a code-example of how you can do it:

Intent intent = getIntent(getApplicationContext(), A.class)

This will make sure that you only have one instance of an activity on the stack.

private static Intent getIntent(Context context, Class<?> cls) {
    Intent intent = new Intent(context, cls);
    intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
    return intent;
}

How to set up a cron job to run an executable every hour?

Since I could not run the C executable that way, I wrote a simple shell script that does the following

cd /..path_to_shell_script
./c_executable_name

In the cron jobs list, I call the shell script.

Base64 String throwing invalid character error

If removing \0 from the end of string is impossible, you can add your own character for each string you encode, and remove it on decode.

Log all requests from the python-requests module

For those using python 3+

import requests
import logging
import http.client

http.client.HTTPConnection.debuglevel = 1

logging.basicConfig()
logging.getLogger().setLevel(logging.DEBUG)
requests_log = logging.getLogger("requests.packages.urllib3")
requests_log.setLevel(logging.DEBUG)
requests_log.propagate = True

How to list files using dos commands?

If you just want to get the file names and not directory names then use :

dir /b /a-d > file.txt

Operation Not Permitted when on root - El Capitan (rootless disabled)

If after calling "csrutil disabled" still your command does not work, try with "sudo" in terminal, for example:

sudo mv geckodriver /usr/local/bin

And it should work.

Getting the name of a variable as a string

This function will print variable name with its value:

import inspect

def print_this(var):
    callers_local_vars = inspect.currentframe().f_back.f_locals.items()
    print(str([k for k, v in callers_local_vars if v is var][0])+': '+str(var))
***Input & Function call:***
my_var = 10

print_this(my_var)

***Output**:*
my_var: 10

How can I map "insert='false' update='false'" on a composite-id key-property which is also used in a one-to-many FK?

I think the annotation you are looking for is:

public class CompanyName implements Serializable {
//...
@JoinColumn(name = "COMPANY_ID", referencedColumnName = "COMPANY_ID", insertable = false, updatable = false)
private Company company;

And you should be able to use similar mappings in a hbm.xml as shown here (in 23.4.2):

http://docs.jboss.org/hibernate/core/3.3/reference/en/html/example-mappings.html

Hex-encoded String to Byte Array

That should do the trick :

byte[] bytes = toByteArray(Str.toCharArray());

public static byte[] toByteArray(char[] array) {
    return toByteArray(array, Charset.defaultCharset());
}

public static byte[] toByteArray(char[] array, Charset charset) {
    CharBuffer cbuf = CharBuffer.wrap(array);
    ByteBuffer bbuf = charset.encode(cbuf);
    return bbuf.array();
}

"Unmappable character for encoding UTF-8" error

You have encoding problem with your sourcecode file. It is maybe ISO-8859-1 encoded, but the compiler was set to use UTF-8. This will results in errors when using characters, which will not have the same bytes representation in UTF-8 and ISO-8859-1. This will happen to all characters which are not part of ASCII, for example ¬ NOT SIGN.

You can simulate this with the following program. It just uses your line of source code and generates a ISO-8859-1 byte array and decode this "wrong" with UTF-8 encoding. You can see at which position the line gets corrupted. I added 2 spaces at your source code to fit position 74 to fit this to ¬ NOT SIGN, which is the only character, which will generate different bytes in ISO-8859-1 encoding and UTF-8 encoding. I guess this will match indentation with the real source file.

 String reg = "      String reg = \"^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[~#;:?/@&!\"'%*=¬.,-])(?=[^\\s]+$).{8,24}$\";";
 String corrupt=new String(reg.getBytes("ISO-8859-1"),"UTF-8");
 System.out.println(corrupt+": "+corrupt.charAt(74));
 System.out.println(reg+": "+reg.charAt(74));     

which results in the following output (messed up because of markup):

String reg = "^(?=.[0-9])(?=.[a-z])(?=.[A-Z])(?=.[~#;:?/@&!"'%*=?.,-])(?=[^\s]+$).{8,24}$";: ?

String reg = "^(?=.[0-9])(?=.[a-z])(?=.[A-Z])(?=.[~#;:?/@&!"'%*=¬.,-])(?=[^\s]+$).{8,24}$";: ¬

See "live" at https://ideone.com/ShZnB

To fix this, save the source files with UTF-8 encoding.

How to Set JPanel's Width and Height?

please, something went xxx*x, and that's not true at all, check that

JButton Size - java.awt.Dimension[width=400,height=40]
JPanel Size - java.awt.Dimension[width=640,height=480]
JFrame Size - java.awt.Dimension[width=646,height=505]

code (basic stuff from Trail: Creating a GUI With JFC/Swing , and yet I still satisfied that that would be outdated )

EDIT: forget setDefaultCloseOperation()

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class FrameSize {

    private JFrame frm = new JFrame();
    private JPanel pnl = new JPanel();
    private JButton btn = new JButton("Get ScreenSize for JComponents");

    public FrameSize() {
        btn.setPreferredSize(new Dimension(400, 40));
        btn.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("JButton Size - " + btn.getSize());
                System.out.println("JPanel Size - " + pnl.getSize());
                System.out.println("JFrame Size - " + frm.getSize());
            }
        });
        pnl.setPreferredSize(new Dimension(640, 480));
        pnl.add(btn, BorderLayout.SOUTH);
        frm.add(pnl, BorderLayout.CENTER);
        frm.setLocation(150, 100);
        frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // EDIT
        frm.setResizable(false);
        frm.pack();
        frm.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                FrameSize fS = new FrameSize();
            }
        });
    }
}

adb not finding my device / phone (MacOS X)

Believe it or not, swapping USB cables solved this for me. I'd been using a random one (which wasn't working), and as soon as I switched over to one that came with an actual Android device, it worked.

Another sign that the good cable was working, was that the Android File Transfer app immediately launched, which wasn't happening with the crappy cable.

Can't install any packages in Node.js using "npm install"

The repository is not down, it looks like they've changed how they host files (I guess they have restored some old code):

Now you have to add the /package-name/ before the -

Eg:

http://registry.npmjs.org/-/npm-1.1.48.tgz
http://registry.npmjs.org/npm/-/npm-1.1.48.tgz

There are 3 ways to solve it:

  • Use a complete mirror:
  • Use a public proxy:

    --registry http://165.225.128.50:8000

  • Host a local proxy:

    https://github.com/hughsk/npm-quickfix

git clone https://github.com/hughsk/npm-quickfix.git
cd npm-quickfix
npm set registry http://localhost:8080/
node index.js

I'd personally go with number 3 and revert to npm set registry http://registry.npmjs.org/ as soon as this get resolved.

Stay tuned here for more info: https://github.com/isaacs/npm/issues/2694

PHP7 : install ext-dom issue

For CentOS, RHEL, Fedora:

$ yum search php-xml
============================================================================================================ N/S matched: php-xml ============================================================================================================
php-xml.x86_64 : A module for PHP applications which use XML
php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php-xmlseclibs.noarch : PHP library for XML Security
php54-php-xml.x86_64 : A module for PHP applications which use XML
php54-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php55-php-xml.x86_64 : A module for PHP applications which use XML
php55-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php56-php-xml.x86_64 : A module for PHP applications which use XML
php56-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php70-php-xml.x86_64 : A module for PHP applications which use XML
php70-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php71-php-xml.x86_64 : A module for PHP applications which use XML
php71-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php72-php-xml.x86_64 : A module for PHP applications which use XML
php72-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
php73-php-xml.x86_64 : A module for PHP applications which use XML
php73-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol

Then select the php-xml version matching your php version:

# php -v
PHP 7.2.11 (cli) (built: Oct 10 2018 10:00:29) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies

# sudo yum install -y php72-php-xml.x86_64

SQL ROWNUM how to return rows between a specific range

I was looking for a solution for this and found this great article explaining the solution Relevant excerpt

My all-time-favorite use of ROWNUM is pagination. In this case, I use ROWNUM to get rows N through M of a result set. The general form is as follows:

select * enter code here
  from ( select /*+ FIRST_ROWS(n) */ 
  a.*, ROWNUM rnum 
      from ( your_query_goes_here, 
      with order by ) a 
      where ROWNUM <= 
      :MAX_ROW_TO_FETCH ) 
where rnum  >= :MIN_ROW_TO_FETCH;

Now with a real example (gets rows 148, 149 and 150):

select *
    from
  (select a.*, rownum rnum
     from
  (select id, data
     from t
   order by id, rowid) a
   where rownum <= 150
  )
   where rnum >= 148;

Appending to list in Python dictionary

Is there a more elegant way to write this code?

Use collections.defaultdict:

from collections import defaultdict

dates_dict = defaultdict(list)
for key, date in cur:
    dates_dict[key].append(date)

MaxLength Attribute not generating client-side validation attributes

MaxLengthAttribute is working since MVC 5.1 update: change notes

What does %~d0 mean in a Windows batch file?

The magic variables %n contains the arguments used to invoke the file: %0 is the path to the bat-file itself, %1 is the first argument after, %2 is the second and so on.

Since the arguments are often file paths, there is some additional syntax to extract parts of the path. ~d is drive, ~p is the path (without drive), ~n is the file name. They can be combined so ~dp is drive+path.

%~dp0 is therefore pretty useful in a bat: it is the folder in which the executing bat file resides.

You can also get other kinds of meta info about the file: ~t is the timestamp, ~z is the size.

Look here for a reference for all command line commands. The tilde-magic codes are described under for.

Rails get index of "each" loop

The two answers are good. And I also suggest you a similar method:

<% @images.each.with_index do |page, index| %>
<% end %>

You might not see the difference between this and the accepted answer. Let me direct your eyes to these method calls: .each.with_index see how it's .each and then .with_index.

Oracle "ORA-01008: not all variables bound" Error w/ Parameters

You might also consider removing the need for duplicated parameter names in your Sql by changing your Sql to

table.Variable2 LIKE '%' || :VarB || '%'

and then getting your client to provide '%' for any value of VarB instead of null. In some ways I think this is more natural.

You could also change the Sql to

table.Variable2 LIKE '%' || IfNull(:VarB, '%') || '%'

Regular expression to extract text between square brackets

I needed including newlines and including the brackets

\[[\s\S]+\]

How can I check if an array contains a specific value in php?

Using dynamic variable for search in array

 /* https://ideone.com/Pfb0Ou */

$array = array('kitchen', 'bedroom', 'living_room', 'dining_room');

/* variable search */
$search = 'living_room';

if (in_array($search, $array)) {
    echo "this array contains $search";
} else
    echo "this array NOT contains $search";

How to Import Excel file into mysql Database from PHP

For >= 2nd row values insert into table-

$file = fopen($filename, "r");
//$sql_data = "SELECT * FROM prod_list_1 ";

$count = 0;                                         // add this line
while (($emapData = fgetcsv($file, 10000, ",")) !== FALSE)
{
    //print_r($emapData);
    //exit();
    $count++;                                      // add this line

    if($count>1){                                  // add this line
      $sql = "INSERT into prod_list_1(p_bench,p_name,p_price,p_reason) values ('$emapData[0]','$emapData[1]','$emapData[2]','$emapData[3]')";
      mysql_query($sql);
    }                                              // add this line
}

Execute bash script from URL

Also:

curl -sL https://.... | sudo bash -

SQL SERVER: Check if variable is null and then assign statement for Where Clause

is null can be used to check whether null data is coming from a query as in following example:

 declare @Mem varchar(20),@flag int
select @mem=MemberClub from [dbo].[UserMaster] where UserID=@uid
if(@Mem is null)
begin
    set @flag= 0;
end
else
begin
    set @flag=1;
end
return @flag;

Fiddler not capturing traffic from browsers

I too faces similar problem, but once I did the below settings, everything was working fine(While working on other application, I selected 'No Proxy' setting in browser which I forgot to revert.Hence, got this problem)

  • In Fiddler, Goto Teleric Fiddler Options->Gateway , then select 'Use System Proxy (recommended)' radio button and click on 'OK' button and restart Fiddler
  • In your Browser(for ex: firefox), Goto Options->Advanced->Network->Settings then select 'Use system proxy settings' radio button and click on OK
  • Now try accessing any URL from that browser, and observe they are being recorded in Fiddler(If you have applied filters, even they will start working)

Hope this helps..

Get back to me with any other problems

How to convert HTML file to word?

just past this on head of your php page. before any code on this should be the top code.

<?php
header("Content-Type: application/vnd.ms-word"); 
header("Expires: 0"); 
header("Cache-Control: must-revalidate, post-check=0, pre-check=0"); 
header("content-disposition: attachment;filename=Hawala.doc");

?>

this will convert all html to MSWORD, now you can customize it according to your client requirement.

Relative paths based on file location instead of current working directory

@Martin Konecny's answer provides the correct answer, but - as he mentions - it only works if the actual script is not invoked through a symlink residing in a different directory.

This answer covers that case: a solution that also works when the script is invoked through a symlink or even a chain of symlinks:


Linux / GNU readlink solution:

If your script needs to run on Linux only or you know that GNU readlink is in the $PATH, use readlink -f, which conveniently resolves a symlink to its ultimate target:

 scriptDir=$(dirname -- "$(readlink -f -- "$BASH_SOURCE")")

Note that GNU readlink has 3 related options for resolving a symlink to its ultimate target's full path: -f (--canonicalize), -e (--canonicalize-existing), and -m (--canonicalize-missing) - see man readlink.
Since the target by definition exists in this scenario, any of the 3 options can be used; I've chosen -f here, because it is the most well-known one.


Multi-(Unix-like-)platform solution (including platforms with a POSIX-only set of utilities):

If your script must run on any platform that:

  • has a readlink utility, but lacks the -f option (in the GNU sense of resolving a symlink to its ultimate target) - e.g., macOS.

    • macOS uses an older version of the BSD implementation of readlink; note that recent versions of FreeBSD/PC-BSD do support -f.
  • does not even have readlink, but has POSIX-compatible utilities - e.g., HP-UX (thanks, @Charles Duffy).

The following solution, inspired by https://stackoverflow.com/a/1116890/45375, defines helper shell function, rreadlink(), which resolves a given symlink to its ultimate target in a loop - this function is in effect a POSIX-compliant implementation of GNU readlink's -e option, which is similar to the -f option, except that the ultimate target must exist.

Note: The function is a bash function, and is POSIX-compliant only in the sense that only POSIX utilities with POSIX-compliant options are used. For a version of this function that is itself written in POSIX-compliant shell code (for /bin/sh), see here.

  • If readlink is available, it is used (without options) - true on most modern platforms.

  • Otherwise, the output from ls -l is parsed, which is the only POSIX-compliant way to determine a symlink's target.
    Caveat: this will break if a filename or path contains the literal substring -> - which is unlikely, however.
    (Note that platforms that lack readlink may still provide other, non-POSIX methods for resolving a symlink; e.g., @Charles Duffy mentions HP-UX's find utility supporting the %l format char. with its -printf primary; in the interest of brevity the function does NOT try to detect such cases.)

  • An installable utility (script) form of the function below (with additional functionality) can be found as rreadlink in the npm registry; on Linux and macOS, install it with [sudo] npm install -g rreadlink; on other platforms (assuming they have bash), follow the manual installation instructions.

If the argument is a symlink, the ultimate target's canonical path is returned; otherwise, the argument's own canonical path is returned.

#!/usr/bin/env bash

# Helper function.
rreadlink() ( # execute function in a *subshell* to localize the effect of `cd`, ...

  local target=$1 fname targetDir readlinkexe=$(command -v readlink) CDPATH= 

  # Since we'll be using `command` below for a predictable execution
  # environment, we make sure that it has its original meaning.
  { \unalias command; \unset -f command; } &>/dev/null

  while :; do # Resolve potential symlinks until the ultimate target is found.
      [[ -L $target || -e $target ]] || { command printf '%s\n' "$FUNCNAME: ERROR: '$target' does not exist." >&2; return 1; }
      command cd "$(command dirname -- "$target")" # Change to target dir; necessary for correct resolution of target path.
      fname=$(command basename -- "$target") # Extract filename.
      [[ $fname == '/' ]] && fname='' # !! curiously, `basename /` returns '/'
      if [[ -L $fname ]]; then
        # Extract [next] target path, which is defined
        # relative to the symlink's own directory.
        if [[ -n $readlinkexe ]]; then # Use `readlink`.
          target=$("$readlinkexe" -- "$fname")
        else # `readlink` utility not available.
          # Parse `ls -l` output, which, unfortunately, is the only POSIX-compliant 
          # way to determine a symlink's target. Hypothetically, this can break with
          # filenames containig literal ' -> ' and embedded newlines.
          target=$(command ls -l -- "$fname")
          target=${target#* -> }
        fi
        continue # Resolve [next] symlink target.
      fi
      break # Ultimate target reached.
  done
  targetDir=$(command pwd -P) # Get canonical dir. path
  # Output the ultimate target's canonical path.
  # Note that we manually resolve paths ending in /. and /.. to make sure we
  # have a normalized path.
  if [[ $fname == '.' ]]; then
    command printf '%s\n' "${targetDir%/}"
  elif  [[ $fname == '..' ]]; then
    # Caveat: something like /var/.. will resolve to /private (assuming
    # /var@ -> /private/var), i.e. the '..' is applied AFTER canonicalization.
    command printf '%s\n' "$(command dirname -- "${targetDir}")"
  else
    command printf '%s\n' "${targetDir%/}/$fname"
  fi
)

# Determine ultimate script dir. using the helper function.
# Note that the helper function returns a canonical path.
scriptDir=$(dirname -- "$(rreadlink "$BASH_SOURCE")")

nginx - read custom header from upstream server

$http_name_of_the_header_key

i.e if you have origin = domain.com in header, you can use $http_origin to get "domain.com"

In nginx does support arbitrary request header field. In the above example last part of a variable name is the field name converted to lower case with dashes replaced by underscores

Reference doc here: http://nginx.org/en/docs/http/ngx_http_core_module.html#var_http_

For your example the variable would be $http_my_custom_header.

Binding ItemsSource of a ComboBoxColumn in WPF DataGrid

the bast way i use i bind the textblock and combobox to same property and this property should support notifyPropertyChanged.

i used relativeresource to bind to parent view datacontext which is usercontrol to go up datagrid level in binding because in this case the datagrid will search in object that you used in datagrid.itemsource

<DataGridTemplateColumn Header="your_columnName">
     <DataGridTemplateColumn.CellTemplate>
          <DataTemplate>
             <TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Path=DataContext.SelectedUnit.Name, Mode=TwoWay}" />
           </DataTemplate>
     </DataGridTemplateColumn.CellTemplate>
     <DataGridTemplateColumn.CellEditingTemplate>
           <DataTemplate>
            <ComboBox DisplayMemberPath="Name"
                      IsEditable="True"
                      ItemsSource="{Binding RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Path=DataContext.UnitLookupCollection}"
                       SelectedItem="{Binding RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Path=DataContext.SelectedUnit, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                      SelectedValue="{Binding UnitId, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                      SelectedValuePath="Id" />
            </DataTemplate>
    </DataGridTemplateColumn.CellEditingTemplate>
</DataGridTemplateColumn>

How to use ArrayList's get() method

To put it nice and simply, get(int index) returns the element at the specified index.

So say we had an ArrayList of Strings:

List<String> names = new ArrayList<String>();
names.add("Arthur Dent");
names.add("Marvin");
names.add("Trillian");
names.add("Ford Prefect");

Which can be visualised as: A visual representation of the array list Where 0, 1, 2, and 3 denote the indexes of the ArrayList.

Say we wanted to retrieve one of the names we would do the following: String name = names.get(1); Which returns the name at the index of 1.

Getting the element at index 1 So if we were to print out the name System.out.println(name); the output would be Marvin - Although he might not be too happy with us disturbing him.

How to generate serial version UID in Intellij

with in the code editor, Open the class you want to create the UID for , Right click -> Generate -> SerialVersionUID. You may need to have the GenerateSerialVersionUID plugin installed for this to work.

jQuery selector to get form by name

You have no combinator (space, >, +...) so no children will get involved, ever.

However, you could avoid the need for jQuery by using an ID and getElementById, or you could use the old getElementsByName("frmSave")[0] or the even older document.forms['frmSave']. jQuery is unnecessary here.

java.text.ParseException: Unparseable date

String date="Sat Jun 01 12:53:10 IST 2013";

SimpleDateFormat sdf=new SimpleDateFormat("MMM d, yyyy HH:mm:ss");

This patterns does not tally with your input String which occurs the exception.

You need to use following pattern to get the work done.

E MMM dd HH:mm:ss z yyyy

Following code will help you to skip the exception.

SimpleDateFormat is used.

    String date="Sat Jun 01 12:53:10 IST 2013"; // Input String

    SimpleDateFormat simpleDateFormat=new SimpleDateFormat("E MMM dd HH:mm:ss z yyyy"); // Existing Pattern

    Date currentdate=simpleDateFormat.parse(date); // Returns Date Format,

    SimpleDateFormat simpleDateFormat1=new SimpleDateFormat("MMM dd,yyyy HH:mm:ss"); // New Pattern

    System.out.println(simpleDateFormat1.format(currentdate)); // Format given String to new pattern

    // outputs: Jun 01,2013 12:53:10

iPhone 6 Plus resolution confusion: Xcode or Apple's website? for development

Real/physical iPhone 6 Plus resolution is 1920x1080 but in Xcode you make your interface for 2208x1242 resolution (736x414 points) and on device it is automatically scaled down to 1920x1080 pixels.

iPhone resolutions quick reference:

Device          Points    Pixels     Scale  Physical Pixels   PPI   Ratio   Size
iPhone XS Max   896x414   2688x1242  3x     2688x1242         458   19.5:9  6.5"
iPhone XR       896x414   1792x828   2x     1792x828          326   19.5:9  6.1"
iPhone X        812x375   2436x1125  3x     2436x1125         458   19.5:9  5.8"
iPhone 6 Plus   736x414   2208x1242  3x     1920x1080         401   16:9    5.5"
iPhone 6        667x375   1334x750   2x     1334x750          326   16:9    4.7"
iPhone 5        568x320   1136x640   2x     1136x640          326   16:9    4.0"
iPhone 4        480x320   960x640    2x     960x640           326   3:2     3.5"
iPhone 3GS      480x320   480x320    1x     480x320           163   3:2     3.5"

iPhone resolutions

How do you test that a Python function throws an exception?

There are a lot of answers here. The code shows how we can create an Exception, how we can use that exception in our methods, and finally, how you can verify in a unit test, the correct exceptions being raised.

import unittest

class DeviceException(Exception):
    def __init__(self, msg, code):
        self.msg = msg
        self.code = code
    def __str__(self):
        return repr("Error {}: {}".format(self.code, self.msg))

class MyDevice(object):
    def __init__(self):
        self.name = 'DefaultName'

    def setParameter(self, param, value):
        if isinstance(value, str):
            setattr(self, param , value)
        else:
            raise DeviceException('Incorrect type of argument passed. Name expects a string', 100001)

    def getParameter(self, param):
        return getattr(self, param)

class TestMyDevice(unittest.TestCase):

    def setUp(self):
        self.dev1 = MyDevice()

    def tearDown(self):
        del self.dev1

    def test_name(self):
        """ Test for valid input for name parameter """

        self.dev1.setParameter('name', 'MyDevice')
        name = self.dev1.getParameter('name')
        self.assertEqual(name, 'MyDevice')

    def test_invalid_name(self):
        """ Test to check if error is raised if invalid type of input is provided """

        self.assertRaises(DeviceException, self.dev1.setParameter, 'name', 1234)

    def test_exception_message(self):
        """ Test to check if correct exception message and code is raised when incorrect value is passed """

        with self.assertRaises(DeviceException) as cm:
            self.dev1.setParameter('name', 1234)
        self.assertEqual(cm.exception.msg, 'Incorrect type of argument passed. Name expects a string', 'mismatch in expected error message')
        self.assertEqual(cm.exception.code, 100001, 'mismatch in expected error code')


if __name__ == '__main__':
    unittest.main()

How to get current CPU and RAM usage in Python?

you can read /proc/meminfo to get used memory

file1 = open('/proc/meminfo', 'r') 

for line in file1: 
    if 'MemTotal' in line: 
        x = line.split()
        memTotal = int(x[1])
        
    if 'Buffers' in line: 
        x = line.split()
        buffers = int(x[1])
        
    if 'Cached' in line and 'SwapCached' not in line: 
        x = line.split()
        cached = int(x[1])
    
    if 'MemFree' in line: 
        x = line.split()
        memFree = int(x[1])

file1.close()

percentage_used = int ( ( memTotal - (buffers + cached + memFree) ) / memTotal * 100 )
print(percentage_used)

jQuery: How can I show an image popup onclick of the thumbnail?

There are a lot of jQuery plugins available for this

Thickbox

LightBox

FancyBox

FaceBox

NyroModal

PiroBox

Thickbox Examples

For a single image

  1. Create a link element ()
  2. Give the link a class attribute with a value of thickbox (class="thickbox")
  3. Provide a path in the href attribute to an image file (.jpg .jpeg .png .gif .bmp)

How to define a List bean in Spring?

Here is one method:

<bean id="stage1" class="Stageclass"/>
<bean id="stage2" class="Stageclass"/>

<bean id="stages" class="java.util.ArrayList">
    <constructor-arg>
        <list>
            <ref bean="stage1" />
            <ref bean="stage2" />                
        </list>
    </constructor-arg>
</bean>

Convert an image (selected by path) to base64 string

That way it's simpler, where you pass the image and then pass the format.

private static string ImageToBase64(Image image)
{
    var imageStream = new MemoryStream();
    try
    {           
        image.Save(imageStream, System.Drawing.Imaging.ImageFormat.Bmp);
        imageStream.Position = 0;
        var imageBytes = imageStream.ToArray();
        var ImageBase64 = Convert.ToBase64String(imageBytes);
        return ImageBase64;
    }
    catch (Exception ex)
    {
        return "Error converting image to base64!";
    }
    finally
    {
      imageStream.Dispose;
    }
}

How to find the operating system version using JavaScript?

Hey for a quick solution you can consider the following library : UAPARSER - https://www.npmjs.com/package/ua-parser-js

example :

<script type="text/javascript" src="ua-parser.min.js"></script>
<script type="text/javascript">

var parser = new UAParser();
console.log(parser.getOS()) // will log  {name: "", version:""}

you can also install the library via npm, and import it like this:

import { UAParser } from 'ua-parser-js';
let parser = new UAParser();
parser.getOS();

the library is a JS based user agent string parser (window.navigator.userAgent is the user agent on browser) , so you can get with it other details aswell such as Browser,device,engines etc..and it can work with node js as well.

if you need typing for the library : https://www.npmjs.com/package/@types/ua-parser-js

What does $1 mean in Perl?

As others have pointed out, the $x are capture variables for regular expressions, allowing you to reference sections of a matched pattern.

Perl also supports named captures which might be easier for humans to remember in some cases.

Given input: 111 222

/(\d+)\s+(\d+)/

$1 is 111

$2 is 222

One could also say:

/(?<myvara>\d+)\s+(?<myvarb>\d+)/

$+{myvara} is 111

$+{myvarb} is 222

What does it mean by select 1 from table?

SELECT 1 FROM TABLE_NAME means, "Return 1 from the table". It is pretty unremarkable on its own, so normally it will be used with WHERE and often EXISTS (as @gbn notes, this is not necessarily best practice, it is, however, common enough to be noted, even if it isn't really meaningful (that said, I will use it because others use it and it is "more obvious" immediately. Of course, that might be a viscous chicken vs. egg issue, but I don't generally dwell)).

 SELECT * FROM TABLE1 T1 WHERE EXISTS (
     SELECT 1 FROM TABLE2 T2 WHERE T1.ID= T2.ID
 );

Basically, the above will return everything from table 1 which has a corresponding ID from table 2. (This is a contrived example, obviously, but I believe it conveys the idea. Personally, I would probably do the above as SELECT * FROM TABLE1 T1 WHERE ID IN (SELECT ID FROM TABLE2); as I view that as FAR more explicit to the reader unless there were a circumstantially compelling reason not to).

EDIT

There actually is one case which I forgot about until just now. In the case where you are trying to determine existence of a value in the database from an outside language, sometimes SELECT 1 FROM TABLE_NAME will be used. This does not offer significant benefit over selecting an individual column, but, depending on implementation, it may offer substantial gains over doing a SELECT *, simply because it is often the case that the more columns that the DB returns to a language, the larger the data structure, which in turn mean that more time will be taken.

Passing multiple values for same variable in stored procedure

Your stored procedure is designed to accept a single parameter, Arg1List. You can't pass 4 parameters to a procedure that only accepts one.

To make it work, the code that calls your procedure will need to concatenate your parameters into a single string of no more than 3000 characters and pass it in as a single parameter.

__init__ and arguments in Python

If you print(type(Num.getone)) you will get <class 'function'>.

It is just a plain function, and be called as usual (with no arguments):

Num.getone() # returns 1  as expected

but if you print print(type(myObj.getone)) you will get <class 'method'>.

So when you call getone() from an instance of the class, Python automatically "transforms" the function defined in a class into a method.

An instance method requires the first argument to be the instance object. You can think myObj.getone() as syntactic sugar for

Num.getone(myObj) # this explains the Error 'getone()' takes no arguments (1 given).

For example:

class Num:
    def __init__(self,num):
        self.n = num
    def getid(self):
        return id(self)

myObj=Num(3)

Now if you

print(id(myObj) == myObj.getid())    
# returns True

As you can see self and myObj are the same object

Use a normal link to submit a form

Two ways. Either create a button and style it so it looks like a link with css, or create a link and use onclick="this.closest('form').submit();return false;".

Finding element's position relative to the document

You can get top and left without traversing DOM like this:

function getCoords(elem) { // crossbrowser version
    var box = elem.getBoundingClientRect();

    var body = document.body;
    var docEl = document.documentElement;

    var scrollTop = window.pageYOffset || docEl.scrollTop || body.scrollTop;
    var scrollLeft = window.pageXOffset || docEl.scrollLeft || body.scrollLeft;

    var clientTop = docEl.clientTop || body.clientTop || 0;
    var clientLeft = docEl.clientLeft || body.clientLeft || 0;

    var top  = box.top +  scrollTop - clientTop;
    var left = box.left + scrollLeft - clientLeft;

    return { top: Math.round(top), left: Math.round(left) };
}

jQuery plugin returning "Cannot read property of undefined"

Usually that problem is that in the last iteration you have an empty object or undefine object. use console.log() inside you cicle to check that this doent happend.

Sometimes a prototype in some place add an extra element.

How to check if a number is a power of 2

Mark gravell suggested this if you have .NET Core 3, System.Runtime.Intrinsics.X86.Popcnt.PopCount

public bool IsPowerOfTwo(uint i)
{
    return Popcnt.PopCount(i) == 1
}

Single instruction, faster than (x != 0) && ((x & (x - 1)) == 0) but less portable.

Is there a way to delete created variables, functions, etc from the memory of the interpreter?

If you are in an interactive environment like Jupyter or ipython you might be interested in clearing unwanted var's if they are getting heavy.

The magic-commands reset and reset_selective is vailable on interactive python sessions like ipython and Jupyter

1) reset

reset Resets the namespace by removing all names defined by the user, if called without arguments.

in and the out parameters specify whether you want to flush the in/out caches. The directory history is flushed with the dhist parameter.

reset in out

Another interesting one is array that only removes numpy Arrays:

reset array

2) reset_selective

Resets the namespace by removing names defined by the user. Input/Output history are left around in case you need them.

Clean Array Example:

In [1]: import numpy as np
In [2]: littleArray = np.array([1,2,3,4,5])
In [3]: who_ls
Out[3]: ['littleArray', 'np']
In [4]: reset_selective -f littleArray
In [5]: who_ls
Out[5]: ['np']

Source: http://ipython.readthedocs.io/en/stable/interactive/magics.html

How to initialize an array in angular2 and typescript

You can use this construct:

export class AppComponent {

    title:string;
    myHero:string;
    heroes: any[];

    constructor() {
       this.title = 'Tour of Heros';
       this.heroes=['Windstorm','Bombasto','Magneta','Tornado']
       this.myHero = this.heroes[0];
    }
}

Java: Why is the Date constructor deprecated, and what do I use instead?

You can make a method just like new Date(year,month,date) in your code by using Calendar class.

private Date getDate(int year,int month,int date){
    Calendar cal = Calendar.getInstance();
    cal.set(Calendar.YEAR, year);
    cal.set(Calendar.MONTH, month-1);
    cal.set(Calendar.DAY_OF_MONTH, day);
    return cal.getTime();
}

It will work just like the deprecated constructor of Date

Bad File Descriptor with Linux Socket write() Bad File Descriptor C

The value you have passed as the file descriptor is not valid. It is either negative or does not represent a currently open file or socket.

So you have either closed the socket before calling write() or you have corrupted the value of 'sockfd' somewhere in your code.

It would be useful to trace all calls to close(), and the value of 'sockfd' prior to the write() calls.

Your technique of only printing error messages in debug mode seems to me complete madness, and in any case calling another function between a system call and perror() is invalid, as it may disturb the value of errno. Indeed it may have done so in this case, and the real underlying error may be different.

Excel 2010: how to use autocomplete in validation list

=OFFSET(NameList!$A$2:$A$200,MATCH(INDIRECT("FillData!"&ADDRESS(ROW(),COLUMN(),4))&"*",NameList!$A$2:$A$200,0)-1,0,COUNTIF($A$2:$A$200,INDIRECT("FillData!"&ADDRESS(ROW(),COLUMN(),4))&"*"),1)
  1. Create sheet name as Namelist. In column A fill list of data.

  2. Create another sheet name as FillData for making data validation list as you want.

  3. Type first alphabet and select, drop down menu will appear depend on you type.

How to redirect to another page using AngularJS?

It might help you!!

The AngularJs code-sample

var app = angular.module('app', ['ui.router']);

app.config(function($stateProvider, $urlRouterProvider) {

  // For any unmatched url, send to /index
  $urlRouterProvider.otherwise("/login");

  $stateProvider
    .state('login', {
      url: "/login",
      templateUrl: "login.html",
      controller: "LoginCheckController"
    })
    .state('SuccessPage', {
      url: "/SuccessPage",
      templateUrl: "SuccessPage.html",
      //controller: "LoginCheckController"
    });
});

app.controller('LoginCheckController', ['$scope', '$location', LoginCheckController]);

function LoginCheckController($scope, $location) {

  $scope.users = [{
    UserName: 'chandra',
    Password: 'hello'
  }, {
    UserName: 'Harish',
    Password: 'hi'
  }, {
    UserName: 'Chinthu',
    Password: 'hi'
  }];

  $scope.LoginCheck = function() {
    $location.path("SuccessPage");
  };

  $scope.go = function(path) {
    $location.path("/SuccessPage");
  };
}

Calling Non-Static Method In Static Method In Java

The only way to call a non-static method from a static method is to have an instance of the class containing the non-static method.

class A
{
    void method()
    {
    }
}
class Demo
{
    static void method2()
    {
        A a=new A();

        a.method();
    }
    /*
    void method3()
    {
        A a=new A();
        a.method();
    }
    */

    public static void main(String args[])
    {
        A a=new A();
        /*an instance of the class is created to access non-static method from a static method */
        a.method();

        method2();

        /*method3();it will show error non-static method can not be  accessed from a static method*/
    }
}

Conditional Replace Pandas

.ix indexer works okay for pandas version prior to 0.20.0, but since pandas 0.20.0, the .ix indexer is deprecated, so you should avoid using it. Instead, you can use .loc or iloc indexers. You can solve this problem by:

mask = df.my_channel > 20000
column_name = 'my_channel'
df.loc[mask, column_name] = 0

Or, in one line,

df.loc[df.my_channel > 20000, 'my_channel'] = 0

mask helps you to select the rows in which df.my_channel > 20000 is True, while df.loc[mask, column_name] = 0 sets the value 0 to the selected rows where maskholds in the column which name is column_name.

Update: In this case, you should use loc because if you use iloc, you will get a NotImplementedError telling you that iLocation based boolean indexing on an integer type is not available.

PHP + MySQL transactions examples

<?php

// trans.php
function begin(){
    mysql_query("BEGIN");
}

function commit(){
    mysql_query("COMMIT");
}

function rollback(){
    mysql_query("ROLLBACK");
}

mysql_connect("localhost","Dude1", "SuperSecret") or die(mysql_error());

mysql_select_db("bedrock") or die(mysql_error());

$query = "INSERT INTO employee (ssn,name,phone) values ('123-45-6789','Matt','1-800-555-1212')";

begin(); // transaction begins

$result = mysql_query($query);

if(!$result){
    rollback(); // transaction rolls back
    echo "transaction rolled back";
    exit;
}else{
    commit(); // transaction is committed
    echo "Database transaction was successful";
}

?>

how to install tensorflow on anaconda python 3.6

I will simply leave this here because none of the other approaches worked for me. Also, I can look it up myself when I need it for new devices.

THIS IS THE WAY IT WORKS:

  1. Install Anaconda
  2. Open Anaconda Prompt
  3. conda create --name tensorflow
  4. conda activate tensorflow
  5. Search with conda search tensorflow for all available TensorFlow versions
  6. Choose the one you need (usually the newest one)
  7. Explicitly name the version now (otherwise it happened to me that version 1.14 was installed): conda install -c conda-forge tensorflow=YOUR_VERSION
  8. Open Anaconda, choose the new environment and install Spyder
  9. Install Microsoft Visual C++ Redistributable for Visual Studio 2015, 2017 and 2019
  10. Download msvcp140.dll and add the .dll-File to the Windows\System32 folder

Now it should work like a charm!

TROUBLESHOOTING:

If it still doesn't work, try this, it worked for me:

Open Anaconda-Prompt:

  1. Create an environment with Python 3.6 like this: conda create --name tensorflow_env python=3.6
  2. conda activate tensorflow
  3. Steps 6. and 6. from the list above
  4. conda install tensorflow=YOUR_VERSION(not forge, just like this!)
  5. Now do steps 8, 9, 10 from above

TENSORFLOW GPU:

If you want to use your GPU, do it the same way as described above, with the only difference to install tensorflow-gpu instead if tensorflow.

And, you must install the newest NVIDIA driver for your GPU, you can find and choose the right one here.

(Yes, in TF 2 there's both, a CPU and GPU support, in the "normal" library. However, if you install tensorflow-gpu via conda, it installs the CUDA and cudNN etc. you need automatically for you - also the right versions. This way easier and faster.)

Force IE compatibility mode off using tags

After many hours troubleshooting this stuff... Here are some quick highlights that helped us from the X-UA-Compatible docs: http://msdn.microsoft.com/en-us/library/cc288325(VS.85).aspx#ctl00_contentContainer_ctl16

Using <meta http-equiv="X-UA-Compatible" content=" _______ " />

  • The Standard User Agent modes (the non-emulate ones) ignore <!DOCTYPE> directives in your page and render based on the standards supported by that version of IE (e.g., IE=8 will better obey table border spacing and some pseudo selectors than IE=7).

  • Whereas, the Emulate modes tell IE to follow any <!DOCTYPE> directives in your page, rendering standards mode based the version you choose and quirks mode based on IE=5

  • Possible values for the content attribute are:

    content="IE=5"

    content="IE=7"

    content="IE=EmulateIE7"

    content="IE=8"

    content="IE=EmulateIE8"

    content="IE=9"

    content="IE=EmulateIE9"

    content="IE=edge"

Recording video feed from an IP camera over a network

about 3 years ago i needed cctv. I found zoneminder, tried to edit it to my liking, but found i was fixing it more than editing it.

Not to mention mp4 recording feature isn't actually part of the master branch (which is kind of lol, since its a cctv program and its already been about 3 years or more since it was suggested). Its literally just adapting the ffmpeg command lol.

So i found the solution!

If you want something done right, do it yourself.

I present to you Shinobi! Shinobi : The Open Source CCTV Platform

enter image description here

How to check model string property for null in a razor view

Try this first, you may be passing a Null Model:

@if (Model != null && !String.IsNullOrEmpty(Model.ImageName))
{
    <label for="Image">Change picture</label>
}
else
{ 
    <label for="Image">Add picture</label>
}

Otherise, you can make it even neater with some ternary fun! - but that will still error if your model is Null.

<label for="Image">@(String.IsNullOrEmpty(Model.ImageName) ? "Add" : "Change") picture</label>

How to encode text to base64 in python

Use the below code:

import base64

#Taking input through the terminal.
welcomeInput= raw_input("Enter 1 to convert String to Base64, 2 to convert Base64 to String: ") 

if(int(welcomeInput)==1 or int(welcomeInput)==2):
    #Code to Convert String to Base 64.
    if int(welcomeInput)==1:
        inputString= raw_input("Enter the String to be converted to Base64:") 
        base64Value = base64.b64encode(inputString.encode())
        print "Base64 Value = " + base64Value
    #Code to Convert Base 64 to String.
    elif int(welcomeInput)==2:
        inputString= raw_input("Enter the Base64 value to be converted to String:") 
        stringValue = base64.b64decode(inputString).decode('utf-8')
        print "Base64 Value = " + stringValue

else:
    print "Please enter a valid value."

Why can I not create a wheel in python?

It could also be that you have a python3 system only. You therefore have installed the necessary packages via pip3 install , like pip3 install wheel.

You'll need to build your stuff using python3 specifically.

python3 setup.py sdist
python3 setup.py bdist_wheel

Cheers.

npx command not found

if you are using Linux system, use sudo command

sudo npm i -g npx

How can I add the sqlite3 module to Python?

Normally, it is included. However, as @ngn999 said, if your python has been built from source manually, you'll have to add it.

Here is an example of a script that will setup an encapsulated version (virtual environment) of Python3 in your user directory with an encapsulated version of sqlite3.

INSTALL_BASE_PATH="$HOME/local"
cd ~
mkdir build
cd build
[ -f Python-3.6.2.tgz ] || wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tgz
tar -zxvf Python-3.6.2.tgz

[ -f sqlite-autoconf-3240000.tar.gz ] || wget https://www.sqlite.org/2018/sqlite-autoconf-3240000.tar.gz
tar -zxvf sqlite-autoconf-3240000.tar.gz

cd sqlite-autoconf-3240000
./configure --prefix=${INSTALL_BASE_PATH}
make
make install

cd ../Python-3.6.2
LD_RUN_PATH=${INSTALL_BASE_PATH}/lib configure
LDFLAGS="-L ${INSTALL_BASE_PATH}/lib"
CPPFLAGS="-I ${INSTALL_BASE_PATH}/include"
LD_RUN_PATH=${INSTALL_BASE_PATH}/lib make
./configure --prefix=${INSTALL_BASE_PATH}
make
make install

cd ~
LINE_TO_ADD="export PATH=${INSTALL_BASE_PATH}/bin:\$PATH"
if grep -q -v "${LINE_TO_ADD}" $HOME/.bash_profile; then echo "${LINE_TO_ADD}" >> $HOME/.bash_profile; fi
source $HOME/.bash_profile

Why do this? You might want a modular python environment that you can completely destroy and rebuild without affecting your managed package installation. This would give you an independent development environment. In this case, the solution is to install sqlite3 modularly too.

A Simple, 2d cross-platform graphics library for c or c++?

One neat engine I came across is Angel-Engine. Info from the project site:

  • Cross-Platform functionality (Windows and Mac)
  • Actors (game objects with color, shape, responses, attributes, etc.)
  • Texturing with Transparency
  • "Animations" (texture swapping at defined intervals)
  • Rigid-Body Physics
    • A clever programmer can do soft-body physics with it
  • Sound
  • Text Rendering with multiple fonts
  • Particle Systems
  • Some basic AI (state machine and pathfinding)
  • Config File Processing
  • Logging
  • Input from a mouse, keyboard, or Xbox 360 controller
    • Binding inputs from a config file
  • Python Scripting
    • In-Game Console

Some users (including me) have succesfully (without any major problems) compiled it under linux.

Argparse: Required arguments listed under "optional arguments"?

Building off of @Karl Rosaen

parser = argparse.ArgumentParser()
optional = parser._action_groups.pop() # Edited this line
required = parser.add_argument_group('required arguments')
# remove this line: optional = parser...
required.add_argument('--required_arg', required=True)
optional.add_argument('--optional_arg')
parser._action_groups.append(optional) # added this line
return parser.parse_args()

and this outputs:

usage: main.py [-h] [--required_arg REQUIRED_ARG]
           [--optional_arg OPTIONAL_ARG]

required arguments:
  --required_arg REQUIRED_ARG

optional arguments:
  -h, --help                    show this help message and exit
  --optional_arg OPTIONAL_ARG

Draw radius around a point in Google map

Using the Google Maps API V3, create a Circle object, then use bindTo() to tie it to the position of your Marker (since they are both google.maps.MVCObject instances).

// Create marker 
var marker = new google.maps.Marker({
  map: map,
  position: new google.maps.LatLng(53, -2.5),
  title: 'Some location'
});

// Add circle overlay and bind to marker
var circle = new google.maps.Circle({
  map: map,
  radius: 16093,    // 10 miles in metres
  fillColor: '#AA0000'
});
circle.bindTo('center', marker, 'position');

You can make it look just like the Google Latitude circle by changing the fillColor, strokeColor, strokeWeight etc (full API).

See more source code and example screenshots.

Android - java.lang.SecurityException: Permission Denial: starting Intent

If you are trying to test your app coded in android studio through your android phone, its generally the issue of your phone. Just uncheck all the USB debugging options and toggle the developer options to OFF. Then restart your phone and switch the developer and USB debugging on. You are ready to go!

How to select a drop-down menu value with Selenium using Python?

from selenium.webdriver.support.ui import Select
driver = webdriver.Ie(".\\IEDriverServer.exe")
driver.get("https://test.com")
select = Select(driver.find_element_by_xpath("""//input[@name='n_name']"""))
select.select_by_index(2)

It will work fine

How to show disable HTML select option in by default?

            <select name="dept" id="dept">
                <option value =''disabled selected>Select Department</option>
                <option value="Computer">Computer</option>
                <option value="electronics">Electronics</option>
                <option value="aidt">AIDT</option>
                <option value="civil">Civil</option>
            </select>

use "SELECTED" which option you want to select by defult. thanks

How to select specific columns in laravel eloquent

Get value of one column:

Table_Name::find($id)->column_name;

you can use this method with where clause:

Table_Name::where('id',$id)->first()->column_name;

or use this method for bypass PhpStorm "Method where not found in App\Models":

Table_Name::query()->where('id','=',$id)->first()->column_name;

in query builder:

DB::table('table_names')->find($id)->column_name;

with where cluase:

DB::table('table_names')->where('id',$id)->first()->column_name;

or

DB::table('table_names')->where('id',$id)->first('column_name');

last method result is array

jQuery make global variable

set the variable on window:

window.a_href = a_href;

Which MySQL datatype to use for an IP address?

You have two possibilities (for an IPv4 address) :

  • a varchar(15), if your want to store the IP address as a string
    • 192.128.0.15 for instance
  • an integer (4 bytes), if you convert the IP address to an integer
    • 3229614095 for the IP I used before


The second solution will require less space in the database, and is probably a better choice, even if it implies a bit of manipulations when storing and retrieving the data (converting it from/to a string).

About those manipulations, see the ip2long() and long2ip() functions, on the PHP-side, or inet_aton() and inet_ntoa() on the MySQL-side.

Accessing dict keys like an attribute?

No need to write your own as setattr() and getattr() already exist.

The advantage of class objects probably comes into play in class definition and inheritance.

string decode utf-8

A string needs no encoding. It is simply a sequence of Unicode characters.

You need to encode when you want to turn a String into a sequence of bytes. The charset the you choose (UTF-8, cp1255, etc.) determines the Character->Byte mapping. Note that a character is not necessarily translated into a single byte. In most charsets, most Unicode characters are translated to at least two bytes.

Encoding of a String is carried out by:

String s1 = "some text";
byte[] bytes = s1.getBytes("UTF-8"); // Charset to encode into

You need to decode when you have ? sequence of bytes and you want to turn them into a String. When y?u d? that you need to specify, again, the charset with which the byt?s were originally encoded (otherwise you'll end up with garbl?d t?xt).

Decoding:

String s2 = new String(bytes, "UTF-8"); // Charset with which bytes were encoded 

If you want to understand this better, a great text is "The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)"

Convert generic List/Enumerable to DataTable?

public DataTable ConvertToDataTable<T>(IList<T> data)
{
    PropertyDescriptorCollection properties =
        TypeDescriptor.GetProperties(typeof(T));

    DataTable table = new DataTable();

    foreach (PropertyDescriptor prop in properties)
            table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);

    foreach (T item in data)
    {
        DataRow row = table.NewRow();
        foreach (PropertyDescriptor prop in properties)
        {
           row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
        }
        table.Rows.Add(row);
    }
    return table;
}

Get current index from foreach loop

You have two options here, 1. Use for instead for foreach for iteration.But in your case the collection is IEnumerable and the upper limit of the collection is unknown so foreach will be the best option. so i prefer to use another integer variable to hold the iteration count: here is the code for that:

int i = 0; // for index
foreach (var row in list)
{
    bool IsChecked;// assign value to this variable
    if (IsChecked)
    {    
       // use i value here                
    }
    i++; // will increment i in each iteration
}

Executable directory where application is running from?

You can write the following:

Path.Combine(Path.GetParentDirectory(GetType(MyClass).Assembly.Location), "Images\image.jpg")

Set height of <div> = to height of another <div> through .css

It seems like what you're looking for is a variant on the CSS Holy Grail Layout, but in two columns. Check out the resources at this answer for more information.

How to avoid "ConcurrentModificationException" while removing elements from `ArrayList` while iterating it?

List myArrayList  = Collections.synchronizedList(new ArrayList());

//add your elements  
 myArrayList.add();
 myArrayList.add();
 myArrayList.add();

synchronized(myArrayList) {
    Iterator i = myArrayList.iterator(); 
     while (i.hasNext()){
         Object  object = i.next();
     }
 }

How do I serialize a Python dictionary into a string, and then back to a dictionary?

If you fully trust the string and don't care about python injection attacks then this is very simple solution:

d = { 'method' : "eval", 'safe' : False, 'guarantees' : None }
s = str(d)
d2 = eval(s)
for k in d2:
    print k+"="+d2[k]

If you're more safety conscious then ast.literal_eval is a better bet.

Do the parentheses after the type name make a difference with new?

In general we have default-initialization in first case and value-initialization in second case.

For example: in case with int (POD type):

  • int* test = new int - we have any initialization and value of *test can be any.

  • int* test = new int() - *test will have 0 value.

next behaviour depended from your type Test. We have defferent cases: Test have defult constructor, Test have generated default constructor, Test contain POD member, non POD member...

Struct inheritance in C++

Yes, c++ struct is very similar to c++ class, except the fact that everything is publicly inherited, ( single / multilevel / hierarchical inheritance, but not hybrid and multiple inheritance ) here is a code for demonstration

_x000D_
_x000D_
#include<bits/stdc++.h>
using namespace std;

struct parent
{
    int data;
    parent() : data(3){};           // default constructor
    parent(int x) : data(x){};      // parameterized constructor
};
struct child : parent
{
    int a , b;
    child(): a(1) , b(2){};             // default constructor
    child(int x, int y) : a(x) , b(y){};// parameterized constructor
    child(int x, int y,int z)           // parameterized constructor
    {
        a = x;
        b = y;
        data = z;
    }
    child(const child &C)               // copy constructor
    {
        a = C.a;
        b = C.b;
        data = C.data;
    }
};
int main()
{
   child c1 ,
         c2(10 , 20),
         c3(10 , 20, 30),
         c4(c3);

    auto print = [](const child &c) { cout<<c.a<<"\t"<<c.b<<"\t"<<c.data<<endl; };

    print(c1);
    print(c2);
    print(c3);
    print(c4);
}
OUTPUT 
1       2       3
10      20      3
10      20      30
10      20      30
_x000D_
_x000D_
_x000D_

Find package name for Android apps to use Intent to launch Market app from web

Once you have the package name, as described Chris Smith's answer, you could/should use an intent url for the link. It's a special format URL that will launch the package if the user has already installed it, or open the play store at the application's page if not...

intent://#Intent;package=qualified.package.name;end

The app needs to support this, with an activity tagged as browsable, but many will.

Should I use pt or px?

A pt is 1/72th of an inch and is a useless measure for anything that is rendered on a device which doesn't calculate the DPI correctly. This makes it a reasonable choice for printing and a dreadful choice for use on screen.

A px is a pixel, which will map on to a screen pixel in most cases.

CSS provides a bunch of other units, and which one you should choose depends on what you are setting the size of.

A pixel is great if you need to size something to match an image, or if you want a thin border.

Percentages are great for font sizes as, if you use them consistently, you get font sizes proportional to the user's preference.

Ems are great when you want an element to size itself based on the font size (so a paragraph might get wider if the font size is larger)

… and so on.

Android device chooser - My device seems offline

I tried everything mutliple times in multiple orders, then stumbled across my particular answer:

Use a different USB cable - suddenly everything worked perfectly.

(Another potential answer for people that I found - make sure there is more than 15mb free space on the device.)

How to increase timeout for a single test case in mocha

This worked for me! Couldn't find anything to make it work with before()

describe("When in a long running test", () => {
  it("Should not time out with 2000ms", async () => {
    let service = new SomeService();
    let result = await service.callToLongRunningProcess();
    expect(result).to.be.true;
  }).timeout(10000); // Custom Timeout 
});

SQL distinct for 2 fields in a database

If you still want to group only by one column (as I wanted) you can nest the query:

select c1, count(*) from (select distinct c1, c2 from t) group by c1

how to show alternate image if source image is not found? (onerror working in IE but not in mozilla)

I think this is very nice and short

<img src="imagenotfound.gif" alt="Image not found" onerror="this.src='imagefound.gif';" />

But, be careful. The user's browser will be stuck in an endless loop if the onerror image itself generates an error.


EDIT To avoid endless loop, remove the onerror from it at once.

<img src="imagenotfound.gif" alt="Image not found" onerror="this.onerror=null;this.src='imagefound.gif';" />

By calling this.onerror=null it will remove the onerror then try to get the alternate image.


NEW I would like to add a jQuery way, if this can help anyone.

<script>
$(document).ready(function()
{
    $(".backup_picture").on("error", function(){
        $(this).attr('src', './images/nopicture.png');
    });
});
</script>

<img class='backup_picture' src='./images/nonexistent_image_file.png' />

You simply need to add class='backup_picture' to any img tag that you want a backup picture to load if it tries to show a bad image.

Can Linux apps be run in Android?

You can install chrooted linux distribution alongside android bacause android is based on linux kernel. If your phone is not rooted, you may use fakeroot (easiest way is to use Debinan nonroot app) even with GUI (with android X-server app or via VNC). If you have a rooted phone, you can install almost fully functional distribution.

I think the best performance and the least limitations you can achieve with Gentoo because all software compiles to your native arm architecture and it is the most flexible, but not the easiest. You may be interested in this post about installing Gentoo on android.

Play a Sound with Python

For Windows, you can use winsound. It's built in

import winsound

winsound.PlaySound('sound.wav', winsound.SND_FILENAME)

You should be able to use ossaudiodev for linux:

from wave import open as waveOpen
from ossaudiodev import open as ossOpen
s = waveOpen('tada.wav','rb')
(nc,sw,fr,nf,comptype, compname) = s.getparams( )
dsp = ossOpen('/dev/dsp','w')
try:
  from ossaudiodev import AFMT_S16_NE
except ImportError:
  from sys import byteorder
  if byteorder == "little":
    AFMT_S16_NE = ossaudiodev.AFMT_S16_LE
  else:
    AFMT_S16_NE = ossaudiodev.AFMT_S16_BE
dsp.setparameters(AFMT_S16_NE, nc, fr)
data = s.readframes(nf)
s.close()
dsp.write(data)
dsp.close()

(Credit for ossaudiodev: Bill Dandreta http://mail.python.org/pipermail/python-list/2004-October/288905.html)

Moq, SetupGet, Mocking a property

ColumnNames is a property of type List<String> so when you are setting up you need to pass a List<String> in the Returns call as an argument (or a func which return a List<String>)

But with this line you are trying to return just a string

input.SetupGet(x => x.ColumnNames).Returns(temp[0]);

which is causing the exception.

Change it to return whole list:

input.SetupGet(x => x.ColumnNames).Returns(temp);

Git merge errors

my issue was (master|REBASE 1/1)

this command worked for me

 git rebase --skip

Hibernate Criteria Query to get specific columns

Use Projections to specify which columns you would like to return.

Example

SQL Query

SELECT user.id, user.name FROM user;

Hibernate Alternative

Criteria cr = session.createCriteria(User.class)
    .setProjection(Projections.projectionList()
      .add(Projections.property("id"), "id")
      .add(Projections.property("Name"), "Name"))
    .setResultTransformer(Transformers.aliasToBean(User.class));

  List<User> list = cr.list();

Postgresql: Scripting psql execution with password

There are several ways to authenticate to PostgreSQL. You may wish to investigate alternatives to password authentication at https://www.postgresql.org/docs/current/static/client-authentication.html.

To answer your question, there are a few ways provide a password for password-based authentication. The obvious way is via the password prompt. Instead of that, you can provide the password in a pgpass file or through the PGPASSWORD environment variable. See these:

There is no option to provide the password as a command line argument because that information is often available to all users, and therefore insecure. However, in Linux/Unix environments you can provide an environment variable for a single command like this:

PGPASSWORD=yourpass psql ...

spring data jpa @query and pageable

With @Query , we can use pagination as well where you need to pass object of Pageable class at end of JPA method

For example:

Pageable pageableRequest = new PageRequest(page, size, Sort.Direction.DESC, rollNo);

Where, page = index of page (index start from zero)
size = No. of records
Sort.Direction = Sorting as per rollNo
rollNo = Field in User class

UserRepository repo
repo.findByFirstname("John", pageableRequest);

public interface UserRepository extends JpaRepository<User, Long> {

  @Query(value = "SELECT * FROM USER WHERE FIRSTNAME = :firstname)
  Page<User> findByLastname(@Param("firstname") String firstname, Pageable pageable);
}

What's the effect of adding 'return false' to a click event listener?

The return false is saying not to take the default action, which in the case of an <a href> is to follow the link. When you return false to the onclick, then the href will be ignored.

How to filter JSON Data in JavaScript or jQuery?

No need for jQuery unless you target old browsers and don't want to use shims.

var yahooOnly = JSON.parse(jsondata).filter(function (entry) {
    return entry.website === 'yahoo';
});

In ES2015:

const yahooOnly = JSON.parse(jsondata).filter(({website}) => website === 'yahoo');

How to get height of entire document with JavaScript?

To get the width in a cross browser/device way use:

function getActualWidth() {
    var actualWidth = window.innerWidth ||
                      document.documentElement.clientWidth ||
                      document.body.clientWidth ||
                      document.body.offsetWidth;

    return actualWidth;
}

How to convert any Object to String?

I've written a few methods for convert by Gson library and java 1.8 .
thay are daynamic model for convert.

string to object

object to string

List to string

string to List

HashMap to String

String to JsonObj

//saeedmpt 
public static String convertMapToString(Map<String, String> data) {
    //convert Map  to String
    return new GsonBuilder().setPrettyPrinting().create().toJson(data);
}
public static <T> List<T> convertStringToList(String strListObj) {
    //convert string json to object List
    return new Gson().fromJson(strListObj, new TypeToken<List<Object>>() {
    }.getType());
}
public static <T> T convertStringToObj(String strObj, Class<T> classOfT) {
    //convert string json to object
    return new Gson().fromJson(strObj, (Type) classOfT);
}

public static JsonObject convertStringToJsonObj(String strObj) {
    //convert string json to object
    return new Gson().fromJson(strObj, JsonObject.class);
}

public static <T> String convertListObjToString(List<T> listObj) {
    //convert object list to string json for
    return new Gson().toJson(listObj, new TypeToken<List<T>>() {
    }.getType());
}

public static String convertObjToString(Object clsObj) {
    //convert object  to string json
    String jsonSender = new Gson().toJson(clsObj, new TypeToken<Object>() {
    }.getType());
    return jsonSender;
}

DOM element to corresponding vue.js component

Exactly what Kamil said,

element = this.$el

But make sure you don't have fragment instances.

How can I set the form action through JavaScript?

Setting form action after selection of option using JavaScript

<script>
    function onSelectedOption(sel) {
        if ((sel.selectedIndex) == 0) {
            document.getElementById("edit").action =
            "http://www.example.co.uk/index.php";
            document.getElementById("edit").submit();
        }
        else
        {
            document.getElementById("edit").action =
            "http://www.example.co.uk/different.php";
            document.getElementById("edit").submit();
        }
    }
</script>

<form name="edit" id="edit" action="" method="GET">
    <input type="hidden" name="id" value="{ID}" />
</form>

<select name="option" id="option" onchange="onSelectedOption(this);">
    <option name="contactBuyer">Edit item</option>
    <option name="relist">End listing</option>
</select>

Java "?" Operator for checking null - What is it? (Not Ternary!)

If someone is looking for an alternative for old java versions, you can try this one I wrote:

/**
 * Strong typed Lambda to return NULL or DEFAULT VALUES instead of runtime errors. 
 * if you override the defaultValue method, if the execution result was null it will be used in place
 * 
 * 
 * Sample:
 * 
 * It won't throw a NullPointerException but null.
 * <pre>
 * {@code
 *  new RuntimeExceptionHandlerLambda<String> () {
 *      @Override
 *      public String evaluate() {
 *          String x = null;
 *          return x.trim();
 *      }  
 *  }.get();
 * }
 * <pre>
 * 
 * 
 * @author Robson_Farias
 *
 */

public abstract class RuntimeExceptionHandlerLambda<T> {

    private T result;

    private RuntimeException exception;

    public abstract T evaluate();

    public RuntimeException getException() {
        return exception;
    }

    public boolean hasException() {
        return exception != null;
    }

    public T defaultValue() {
        return result;
    }

    public T get() {
        try {
            result = evaluate();
        } catch (RuntimeException runtimeException) {
            exception = runtimeException;
        }
        return result == null ? defaultValue() : result;
    }

}

JPanel setBackground(Color.BLACK) does nothing

You have to call the super.paintComponent(); as well, to allow the Java API draw the original background. The super refers to the original JPanel code.

public void paintComponent(Graphics g){
    super.paintComponent(g);

    g.setColor(Color.red);
    g.fillOval(player.getxCenter(), player.getyCenter(), player.getRadius(), player.getRadius());
}

Plotting dates on the x-axis with Python's matplotlib

You can do this more simply using plot() instead of plot_date().

First, convert your strings to instances of Python datetime.date:

import datetime as dt

dates = ['01/02/1991','01/03/1991','01/04/1991']
x = [dt.datetime.strptime(d,'%m/%d/%Y').date() for d in dates]
y = range(len(x)) # many thanks to Kyss Tao for setting me straight here

Then plot:

import matplotlib.pyplot as plt
import matplotlib.dates as mdates

plt.gca().xaxis.set_major_formatter(mdates.DateFormatter('%m/%d/%Y'))
plt.gca().xaxis.set_major_locator(mdates.DayLocator())
plt.plot(x,y)
plt.gcf().autofmt_xdate()

Result:

enter image description here

Best way to encode text data for XML

This might be the case where you could benefit from using the WriteCData method.

public override void WriteCData(string text)
    Member of System.Xml.XmlTextWriter

Summary:
Writes out a <![CDATA[...]]> block containing the specified text.

Parameters:
text: Text to place inside the CDATA block.

A simple example would look like the following:

writer.WriteStartElement("name");
writer.WriteCData("<unsafe characters>");
writer.WriteFullEndElement();

The result looks like:

<name><![CDATA[<unsafe characters>]]></name>

When reading the node values the XMLReader automatically strips out the CData part of the innertext so you don't have to worry about it. The only catch is that you have to store the data as an innerText value to an XML node. In other words, you can't insert CData content into an attribute value.

Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2:java (default-cli)

Your problem is that you have declare twice the exec-maven-plugin :

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.2.1</version>
    <executions>
        <execution>
            <goals>
                <goal>java</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <mainClass>C:\apache-camel-2.11.0\examples\camel-example-smooks-  
      integration\src\main\java\example\Main< /mainClass>
    </configuration>
</plugin>

...

< plugin>
    < groupId>org.codehaus.mojo</groupId>
    < artifactId>exec-maven-plugin</artifactId>
    < version>1.2</version>
< /plugin>

Setting a timeout for socket operations

You can't control the timeout due to UnknownHostException. These are DNS timings. You can only control the connect timeout given a valid host. None of the preceding answers addresses this point correctly.

But I find it hard to believe that you are really getting an UnknownHostException when you specify an IP address rather than a hostname.

EDIT To control Java's DNS timeouts see this answer.

Declaring an HTMLElement Typescript

The type comes after the name in TypeScript, partly because types are optional.

So your line:

HTMLElement el = document.getElementById('content');

Needs to change to:

const el: HTMLElement = document.getElementById('content');

Back in 2013, the type HTMLElement would have been inferred from the return value of getElementById, this is still the case if you aren't using strict null checks (but you ought to be using the strict modes in TypeScript). If you are enforcing strict null checks you will find the return type of getElementById has changed from HTMLElement to HTMLElement | null. The change makes the type more correct, because you don't always find an element.

So when using type mode, you will be encouraged by the compiler to use a type assertion to ensure you found an element. Like this:

const el: HTMLElement | null = document.getElementById('content');

if (el) {
  const definitelyAnElement: HTMLElement = el;
}

I have included the types to demonstrate what happens when you run the code. The interesting bit is that el has the narrower type HTMLElement within the if statement, due to you eliminating the possibility of it being null.

You can do exactly the same thing, with the same resulting types, without any type annotations. They will be inferred by the compiler, thus saving all that extra typing:

const el = document.getElementById('content');

if (el) {
  const definitelyAnElement = el;
}

How to give the background-image path in CSS?

You need to get 2 folders back from your css file.

Try:

background-image: url("../../images/image.png");

Python check if website exists

from urllib2 import Request, urlopen, HTTPError, URLError

user_agent = 'Mozilla/20.0.1 (compatible; MSIE 5.5; Windows NT)'
headers = { 'User-Agent':user_agent }
link = "http://www.abc.com/"
req = Request(link, headers = headers)
try:
        page_open = urlopen(req)
except HTTPError, e:
        print e.code
except URLError, e:
        print e.reason
else:
        print 'ok'

To answer the comment of unutbu:

Because the default handlers handle redirects (codes in the 300 range), and codes in the 100-299 range indicate success, you will usually only see error codes in the 400-599 range. Source

IE throws JavaScript Error: The value of the property 'googleMapsQuery' is null or undefined, not a Function object (works in other browsers)

Have you tried adding the semicolon to onclick="googleMapsQuery(422111);". I don't have enough of your code to test if the missing semicolon would cause the error, but ie is more picky about syntax.

Flask SQLAlchemy query, specify column names

You can use Model.query, because the Model (or usually its base class, especially in cases where declarative extension is used) is assigned Sesssion.query_property. In this case the Model.query is equivalent to Session.query(Model).

I am not aware of the way to modify the columns returned by the query (except by adding more using add_columns()).
So your best shot is to use the Session.query(Model.col1, Model.col2, ...) (as already shown by Salil).

C++: constructor initializer for arrays

There is no array-construction syntax that ca be used in this context, at least not directly. You can accomplish what you're trying to accomplish by something along the lines of:

Bar::Bar()
{
    static const int inits [] = {4,5,6};
    static const size_t numInits = sizeof(inits)/sizeof(inits[0]);
    std::copy(&inits[0],&inits[numInits],foo);  // be careful that there are enough slots in foo
}

...but you'll need to give Foo a default constructor.

Unix epoch time to Java Date object

Better yet, use JodaTime. Much easier to parse strings and into strings. Is thread safe as well. Worth the time it will take you to implement it.

Problems when trying to load a package in R due to rJava

For reading/writing excel files, you can use :

  • readxl package for reading and writexl package for writing
  • openxlsx package for reading and writing

With xlsx and XLConnect (which use rjava) you will face memory errors if you have large files

Why do many examples use `fig, ax = plt.subplots()` in Matplotlib/pyplot/python

plt.subplots() is a function that returns a tuple containing a figure and axes object(s). Thus when using fig, ax = plt.subplots() you unpack this tuple into the variables fig and ax. Having fig is useful if you want to change figure-level attributes or save the figure as an image file later (e.g. with fig.savefig('yourfilename.png')). You certainly don't have to use the returned figure object but many people do use it later so it's common to see. Also, all axes objects (the objects that have plotting methods), have a parent figure object anyway, thus:

fig, ax = plt.subplots()

is more concise than this:

fig = plt.figure()
ax = fig.add_subplot(111)

What is the preferred syntax for initializing a dict: curly brace literals {} or the dict() function?

I think the first option is better because you are going to access the values as a['a'] or a['another']. The keys in your dictionary are strings, and there is no reason to pretend they are not. To me the keyword syntax looks clever at first, but obscure at a second look. This only makes sense to me if you are working with __dict__, and the keywords are going to become attributes later, something like that.

"The operation is not valid for the state of the transaction" error and transaction scope

When I encountered this exception, there was an InnerException "Transaction Timeout". Since this was during a debug session, when I halted my code for some time inside the TransactionScope, I chose to ignore this issue.

When this specific exception with a timeout appears in deployed code, I think that the following section in you .config file will help you out:

<system.transactions> 
        <machineSettings maxTimeout="00:05:00" /> 
</system.transactions>

Enabling CORS in Cloud Functions for Firebase

A cors error can occur if you don't catch an error in a function. My suggestion is to implement a try catch in your corsHandler

const corsHandler = (request, response, handler) => {
    cors({ origin: true })(request, response, async () => {
        try {
            await handler();
        }
        catch (e) {
            functions.logger.error('Error: ' + e);
            response.statusCode = 500;
            response.send({
                'status': 'ERROR' //Optional: customize your error message here
            });
        }
    });
};

Usage:

exports.helloWorld = functions.https.onRequest((request, response) => {
    corsHandler(request, response, () => {
        functions.logger.info("Hello logs!");
        response.send({
            "data": "Hello from Firebase!"
        });
    });
});

Thanks to stackoverflow users: Hoang Trinh, Yayo Arellano and Doug Stevenson

SQL Update to the SUM of its joined values

How about this:

UPDATE p
SET p.extrasPrice = t.sumPrice
FROM BookingPitches AS p
INNER JOIN
    (
        SELECT PitchID, SUM(Price) sumPrice
        FROM BookingPitchExtras
        WHERE [required] = 1
        GROUP BY PitchID 
    ) t
    ON t.PitchID = p.ID
WHERE p.bookingID = 1

Get keys of a Typescript interface as array of strings

// declarations.d.ts
export interface IMyTable {
      id: number;
      title: string;
      createdAt: Date;
      isDeleted: boolean
}
declare var Tes: IMyTable;
// call in annother page
console.log(Tes.id);

How to change date format (MM/DD/YY) to (YYYY-MM-DD) in date picker

just add dateFormat:'yy-mm-dd' to your .datepicker({}) settings, your .datepicker({}) can look something like this

            $( "#datepicker" ).datepicker({
                showButtonPanel: true,
                changeMonth: true,
                dateFormat: 'yy-mm-dd'
            });
          });

    </script> 

Why doesn't height: 100% work to expand divs to the screen height?

Since nobody has mentioned this..

Modern Approach:

As an alternative to setting both the html/body element's heights to 100%, you could also use viewport-percentage lengths:

5.1.2. Viewport-percentage lengths: the ‘vw’, ‘vh’, ‘vmin’, ‘vmax’ units

The viewport-percentage lengths are relative to the size of the initial containing block. When the height or width of the initial containing block is changed, they are scaled accordingly.

In this instance, you could use the value 100vh (which is the height of the viewport) - (example)

body {
    height: 100vh;
}

Setting a min-height also works. (example)

body {
    min-height: 100vh;
}

These units are supported in most modern browsers - support can be found here.

Git push rejected after feature branch rebase

My way of avoiding the force push is to create a new branch and continuing work on that new branch and after some stability, remove the old branch that was rebased:

  • Rebasing the checked out branch locally
  • Branching from the rebased branch to a new branch
  • Pushing that branch as a new branch to remote. and deleting the old branch on remote

Determine if a String is an Integer in Java

You can use Integer.parseInt(str) and catch the NumberFormatException if the string is not a valid integer, in the following fashion (as pointed out by all answers):

static boolean isInt(String s)
{
 try
  { int i = Integer.parseInt(s); return true; }

 catch(NumberFormatException er)
  { return false; }
}

However, note here that if the evaluated integer overflows, the same exception will be thrown. Your purpose was to find out whether or not, it was a valid integer. So its safer to make your own method to check for validity:

static boolean isInt(String s)  // assuming integer is in decimal number system
{
 for(int a=0;a<s.length();a++)
 {
    if(a==0 && s.charAt(a) == '-') continue;
    if( !Character.isDigit(s.charAt(a)) ) return false;
 }
 return true;
}

How to make a browser display a "save as dialog" so the user can save the content of a string to a file on his system?

Using execComand:

<input type="button" name="save" value="Save" onclick="javascript:document.execCommand('SaveAs','true','your_file.txt')">

In the next link: execCommand

Importing variables from another file?

first.py:

a=5

second.py:

import first
print(first.a)

The result will be 5.

Node.js + Nginx - What now?

The best and simpler setup with Nginx and Nodejs is to use Nginx as an HTTP and TCP load balancer with proxy_protocol enabled. In this context, Nginx will be able to proxy incoming requests to nodejs, and also terminate SSL connections to the backend Nginx server(s), and not to the proxy server itself. (SSL-PassThrough)

In my opinion, there is no point in giving non-SSL examples, since all web apps are (or should be) using secure environments.

Example config for the proxy server, in /etc/nginx/nginx.conf

user  nginx;
worker_processes  1;
error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;
events {
    worker_connections  1024;
}
http {
  upstream webserver-http {
    server 192.168.1.4; #use a host port instead if using docker
    server 192.168.1.5; #use a host port instead if using docker
  }
  upstream nodejs-http {
    server 192.168.1.4:8080; #nodejs listening port
    server 192.168.1.5:8080; #nodejs listening port
  }
  server {
    server_name example.com;
    location / {
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $scheme;
      proxy_set_header Host $http_host;
      proxy_set_header X-Forwarded-Host $server_name;
      proxy_set_header Connection "";
      add_header       X-Upstream $upstream_addr;
      proxy_redirect     off;
      proxy_connect_timeout  300;
      proxy_http_version 1.1;
      proxy_buffers 16 16k;
      proxy_buffer_size 16k;
      proxy_cache_background_update on;
      proxy_pass http://webserver-http$request_uri;
    }
  }
  server {
    server_name node.example.com;
    location / {
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $scheme;
      proxy_set_header Host $http_host;
      proxy_set_header X-Forwarded-Host $server_name;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "Upgrade";
      add_header       X-Upstream $upstream_addr;
      proxy_redirect     off;
      proxy_connect_timeout  300;
      proxy_http_version 1.1;
      proxy_buffers 16 16k;
      proxy_buffer_size 16k;
      proxy_cache_background_update on;
      proxy_pass http://nodejs-http$request_uri;
    }
  }
}
stream {
  upstream webserver-https {
    server 192.168.1.4:443; #use a host port instead if using docker
    server 192.168.1.5:443; #use a host port instead if using docker
  }

  server {
    proxy_protocol on;
    tcp_nodelay on;
    listen 443;
    proxy_pass webserver-https;
  }
  log_format proxy 'Protocol: $protocol - $status $bytes_sent $bytes_received $session_time';
  access_log  /var/log/nginx/access.log proxy;
  error_log /var/log/nginx/error.log debug;
}

Now, let's handle the backend webserver. /etc/nginx/nginx.conf:

user  nginx;
worker_processes  1;
error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;
load_module /etc/nginx/modules/ngx_http_geoip2_module.so; # GeoIP2
events {
    worker_connections  1024;
}
http {
    variables_hash_bucket_size 64;
    variables_hash_max_size 2048;
    server_tokens off;
    sendfile    on;
    tcp_nopush  on;
    tcp_nodelay on;
    autoindex off;
    keepalive_timeout  30;
    types_hash_bucket_size 256;
    client_max_body_size 100m;
    server_names_hash_bucket_size 256;
    include         mime.types;
    default_type    application/octet-stream;
    index  index.php index.html index.htm;
    # GeoIP2
    log_format  main    'Proxy Protocol Address: [$proxy_protocol_addr] '
                        '"$request" $remote_addr - $remote_user [$time_local] "$request" '
                        '$status $body_bytes_sent "$http_referer" '
                        '"$http_user_agent" "$http_x_forwarded_for"';

    # GeoIP2
    log_format  main_geo    'Original Client Address: [$realip_remote_addr]- Proxy Protocol Address: [$proxy_protocol_addr] '
                            'Proxy Protocol Server Address:$proxy_protocol_server_addr - '
                            '"$request" $remote_addr - $remote_user [$time_local] "$request" '
                            '$status $body_bytes_sent "$http_referer" '
                            '$geoip2_data_country_iso $geoip2_data_country_name';

    access_log  /var/log/nginx/access.log  main_geo; # GeoIP2
#===================== GEOIP2 =====================#
    geoip2 /usr/share/geoip/GeoLite2-Country.mmdb {
        $geoip2_metadata_country_build  metadata build_epoch;
        $geoip2_data_country_geonameid  country geoname_id;
        $geoip2_data_country_iso        country iso_code;
        $geoip2_data_country_name       country names en;
        $geoip2_data_country_is_eu      country is_in_european_union;
    }
    #geoip2 /usr/share/geoip/GeoLite2-City.mmdb {
    #   $geoip2_data_city_name city names en;
    #   $geoip2_data_city_geonameid city geoname_id;
    #   $geoip2_data_continent_code continent code;
    #   $geoip2_data_continent_geonameid continent geoname_id;
    #   $geoip2_data_continent_name continent names en;
    #   $geoip2_data_location_accuracyradius location accuracy_radius;
    #   $geoip2_data_location_latitude location latitude;
    #   $geoip2_data_location_longitude location longitude;
    #   $geoip2_data_location_metrocode location metro_code;
    #   $geoip2_data_location_timezone location time_zone;
    #   $geoip2_data_postal_code postal code;
    #   $geoip2_data_rcountry_geonameid registered_country geoname_id;
    #   $geoip2_data_rcountry_iso registered_country iso_code;
    #   $geoip2_data_rcountry_name registered_country names en;
    #   $geoip2_data_rcountry_is_eu registered_country is_in_european_union;
    #   $geoip2_data_region_geonameid subdivisions 0 geoname_id;
    #   $geoip2_data_region_iso subdivisions 0 iso_code;
    #   $geoip2_data_region_name subdivisions 0 names en;
   #}

#=================Basic Compression=================#
    gzip on;
    gzip_disable "msie6";
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;
    gzip_types text/css text/xml text/plain application/javascript image/jpeg image/png image/gif image/x-icon image/svg+xml image/webp application/font-woff application/json application/vnd.ms-fontobject application/vnd.ms-powerpoint;
    gzip_static on;
    
    include /etc/nginx/sites-enabled/example.com-https.conf;
}

Now, let's configure the virtual host with this SSL and proxy_protocol enabled config at /etc/nginx/sites-available/example.com-https.conf:

server {
    real_ip_header proxy_protocol;
    set_real_ip_from 192.168.1.1; #proxy server ip address
    #set_real_ip_from proxy; #proxy container hostname if you are using docker
    server_name 192.168.1.4; #Your current server ip address. It will redirect to the domain name.
    listen 80;
    listen 443 ssl http2;
    listen [::]:80;
    listen [::]:443 ssl http2;
    ssl_certificate     /etc/nginx/certs/example.com.crt;
    ssl_certificate_key /etc/nginx/certs/example.com.key;
    ssl_dhparam /etc/nginx/ssl/dhparam.pem;
    return 301 https://example.com$request_uri;
}
server {
    real_ip_header proxy_protocol;
    set_real_ip_from 192.168.1.1; #proxy server ip address
    #set_real_ip_from proxy; #proxy container hostname if you are using docker
    server_name  example.com;
    listen       *:80;
    return 301   https://example.com$request_uri;
}
server {
    real_ip_header proxy_protocol;
    set_real_ip_from 192.168.1.1; #proxy server ip address
    #set_real_ip_from proxy; #proxy container hostname if you are using docker
    server_name www.example.com;
    listen 80;
    listen 443 http2;
    listen [::]:80;
    listen [::]:443 ssl http2 ;
    ssl_certificate     /etc/nginx/certs/example.com.crt;
    ssl_certificate_key /etc/nginx/certs/example.com.key;
    ssl_dhparam /etc/nginx/ssl/dhparam.pem;
    return 301 https://example.com$request_uri;
}
server {
    real_ip_header proxy_protocol;
    set_real_ip_from 192.168.1.1; #proxy server ip address
    #set_real_ip_from proxy; #proxy container hostname if you are using docker
    server_name example.com;
    listen 443 proxy_protocol ssl http2;
    listen [::]:443 proxy_protocol ssl http2;
    root /var/www/html;
    charset UTF-8;
    add_header Strict-Transport-Security 'max-age=31536000; includeSubDomains; preload';
    add_header X-Frame-Options SAMEORIGIN;
    add_header X-Content-Type-Options nosniff;
    add_header X-XSS-Protection "1; mode=block";
    add_header Referrer-Policy no-referrer;
    ssl_prefer_server_ciphers on;
    ssl_ciphers "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH";
    ssl_protocols TLSv1.2 TLSv1.1 TLSv1;
    ssl_session_cache   shared:SSL:10m;
    ssl_session_timeout 10m;
    keepalive_timeout   70;
    ssl_buffer_size 1400;
    ssl_dhparam /etc/nginx/ssl/dhparam.pem;
    ssl_stapling on;
    ssl_stapling_verify on;
    resolver 8.8.8.8 8.8.4.4 valid=86400;
    resolver_timeout 10;
    ssl_certificate     /etc/nginx/certs/example.com.crt;
    ssl_certificate_key /etc/nginx/certs/example.com.key;
    ssl_trusted_certificate /etc/nginx/certs/example.com.crt;
location ~* \.(jpg|jpe?g|gif|png|ico|cur|gz|svgz|mp4|ogg|ogv|webm|htc|css|js|otf|eot|svg|ttf|woff|woff2)(\?ver=[0-9.]+)?$ {
    expires modified 1M;
    add_header Access-Control-Allow-Origin '*';
    add_header Pragma public;
    add_header Cache-Control "public, must-revalidate, proxy-revalidate";
    access_log off;
    }
    location ~ /.well-known { #For issuing LetsEncrypt Certificates
        allow all;
    }
location / {
    index index.php;
    try_files $uri $uri/ /index.php?$args;
    }
error_page  404    /404.php;

location ~ \.php$ {
    try_files       $uri =404;
    fastcgi_index   index.php;
    fastcgi_pass    unix:/tmp/php7-fpm.sock;
    #fastcgi_pass    php-container-hostname:9000; (if using docker)
    fastcgi_pass_request_headers on;
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    fastcgi_param   SCRIPT_FILENAME  $document_root$fastcgi_script_name;
    fastcgi_intercept_errors on;
    fastcgi_ignore_client_abort off;
    fastcgi_connect_timeout 60;
    fastcgi_send_timeout 180;
    fastcgi_read_timeout 180;
    fastcgi_request_buffering on;
    fastcgi_buffer_size 128k;
    fastcgi_buffers 4 256k;
    fastcgi_busy_buffers_size 256k;
    fastcgi_temp_file_write_size 256k;
    include fastcgi_params;
}
location = /robots.txt {
    access_log off;
    log_not_found off;
    }
location ~ /\. {
    deny  all;
    access_log off;
    log_not_found off;
    }
}

And lastly, a sample of 2 nodejs webservers: First server:

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello From Nodejs\n');
}).listen(8080, "192.168.1.4");
console.log('Server running at http://192.168.1.4:8080/');

Second server:

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello From Nodejs\n');
}).listen(8080, "192.168.1.5");
console.log('Server running at http://192.168.1.5:8080/');

Now everything should be perfectly working and load-balanced.

A while back i wrote about How to set up Nginx as a TCP load balancer in Docker. Check it out if you are using Docker.

How to completely DISABLE any MOUSE CLICK

something like:

    $('#doc').click(function(e){
       e.preventDefault()
       e.stopImmediatePropagation() //charles ma is right about that, but stopPropagation isn't also needed
});

should do the job you could also bind more mouse events with replacing for: edit: add this in the feezing part

    $('#doc').bind('click mousedown dblclick',function(e){
       e.preventDefault()
       e.stopImmediatePropagation()
});

and this in the unfreezing:

  $('#doc').unbind();

How to implement the Java comparable interface?

Possible alternative from the source code of Integer.compare method which requires API Version 19 is :

public int compareTo(Animal other) { return Integer.valueOf(this.year_discovered).compareTo(other.year_discovered); }

This alternative does not require you to use API version 19.

How to persist data in a dockerized postgres database using volumes

I would avoid using a relative path. Remember that docker is a daemon/client relationship.

When you are executing the compose, it's essentially just breaking down into various docker client commands, which are then passed to the daemon. That ./database is then relative to the daemon, not the client.

Now, the docker dev team has some back and forth on this issue, but the bottom line is it can have some unexpected results.

In short, don't use a relative path, use an absolute path.

I want to delete all bin and obj folders to force all projects to rebuild everything

Considering the PS1 file is present in the currentFolder (the folder within which you need to delete bin and obj folders)

$currentPath = $MyInvocation.MyCommand.Path
$currentFolder = Split-Path $currentPath

Get-ChildItem $currentFolder -include bin,obj -Recurse | foreach ($_) { remove-item $_.fullname -Force -Recurse }

django import error - No module named core.management

Try change your first line of manage.py.

Change

#!/usr/bin/python

by

#!/usr/bin/env python

Print a variable in hexadecimal in Python

A way that will fail if your input string isn't valid pairs of hex characters...:

>>> import binascii
>>> ' '.join(hex(ord(i)) for i in binascii.unhexlify('deadbeef'))
'0xde 0xad 0xbe 0xef'

Google API for location, based on user IP address

Here's a script that will use the Google API to acquire the users postal code and populate an input field.

function postalCodeLookup(input) {
    var head= document.getElementsByTagName('head')[0],
        script= document.createElement('script');
    script.src= '//maps.googleapis.com/maps/api/js?sensor=false';
    head.appendChild(script);
    script.onload = function() {
        if (navigator.geolocation) {
            var a = input,
                fallback = setTimeout(function () {
                    fail('10 seconds expired');
                }, 10000);

            navigator.geolocation.getCurrentPosition(function (pos) {
                clearTimeout(fallback);
                var point = new google.maps.LatLng(pos.coords.latitude, pos.coords.longitude);
                new google.maps.Geocoder().geocode({'latLng': point}, function (res, status) {
                    if (status == google.maps.GeocoderStatus.OK && typeof res[0] !== 'undefined') {
                        var zip = res[0].formatted_address.match(/,\s\w{2}\s(\d{5})/);
                        if (zip) {
                            a.value = zip[1];
                        } else fail('Unable to look-up postal code');
                    } else {
                        fail('Unable to look-up geolocation');
                    }
                });
            }, function (err) {
                fail(err.message);
            });
        } else {
            alert('Unable to find your location.');
        }
        function fail(err) {
            console.log('err', err);
            a.value('Try Again.');
        }
    };
}

You can adjust accordingly to acquire different information. For more info, check out the Google Maps API documentation.

MySQL SELECT last few days?

You can use this in your MySQL WHERE clause to return records that were created within the last 7 days/week:

created >= DATE_SUB(CURDATE(),INTERVAL 7 day)

Also use NOW() in the subtraction to give hh:mm:ss resolution. So to return records created exactly (to the second) within the last 24hrs, you could do:

created >= DATE_SUB(NOW(),INTERVAL 1 day)

angular-cli server - how to specify default port

Use npm scripts instead... Edit your package.json and add the command to script section.

{
  "name": "my new project",
  "version": "0.0.0",
  "license": "MIT",
  "angular-cli": {},
  "scripts": {
    "ng": "ng",
    "start": "ng serve --host 0.0.0.0 --port 8080",
    "lint": "tslint \"src/**/*.ts\" --project src/tsconfig.json --type-check && tslint \"e2e/**/*.ts\" --project e2e/tsconfig.json --type-check",
    "test": "ng test",
    "pree2e": "webdriver-manager update --standalone false --gecko false",
    "e2e": "protractor"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^2.3.1",
    "@angular/compiler": "^2.3.1",
    "@angular/core": "^2.3.1",
    "@angular/forms": "^2.3.1",
    "@angular/http": "^2.3.1",
    "@angular/platform-browser": "^2.3.1",
    "@angular/platform-browser-dynamic": "^2.3.1",
    "@angular/router": "^3.3.1",
    "core-js": "^2.4.1",
    "rxjs": "^5.0.1",
    "ts-helpers": "^1.1.1",
    "zone.js": "^0.7.2"
  },
  "devDependencies": {
    "@angular/compiler-cli": "^2.3.1",
    "@types/jasmine": "2.5.38",
    "@types/node": "^6.0.42",
    "angular-cli": "1.0.0-beta.26",
    "codelyzer": "~2.0.0-beta.1",
    "jasmine-core": "2.5.2",
    "jasmine-spec-reporter": "2.5.0",
    "karma": "1.2.0",
    "karma-chrome-launcher": "^2.0.0",
    "karma-cli": "^1.0.1",
    "karma-jasmine": "^1.0.2",
    "karma-remap-istanbul": "^0.2.1",
    "protractor": "~4.0.13",
    "ts-node": "1.2.1",
    "tslint": "^4.3.0",
    "typescript": "~2.0.3"
  }
}

Then just execute npm start

Calculating how many days are between two dates in DB2?

It seems like one closing brace is missing at ,right(a2.chdlm,2)))) from sysibm.sysdummy1 a1,

So your Query will be

select days(current date) - days(date(select concat(concat(concat(concat(left(a2.chdlm,4),'-'),substr(a2.chdlm,4,2)),'-'),right(a2.chdlm,2)))) from sysibm.sysdummy1 a1, chcart00 a2 where chstat = '05';

How to split a string and assign it to variables

package main

import (
    "fmt"
    "strings"
)

func main() {
    strs := strings.Split("127.0.0.1:5432", ":")
    ip := strs[0]
    port := strs[1]
    fmt.Println(ip, port)
}

Here is the definition for strings.Split

// Split slices s into all substrings separated by sep and returns a slice of
// the substrings between those separators.
//
// If s does not contain sep and sep is not empty, Split returns a
// slice of length 1 whose only element is s.
//
// If sep is empty, Split splits after each UTF-8 sequence. If both s
// and sep are empty, Split returns an empty slice.
//
// It is equivalent to SplitN with a count of -1.
func Split(s, sep string) []string { return genSplit(s, sep, 0, -1) }

Colorplot of 2D array matplotlib

I'm afraid your posted example is not working, since X and Y aren't defined. So instead of pcolormesh let's use imshow:

import numpy as np
import matplotlib.pyplot as plt

H = np.array([[1, 2, 3, 4],
              [5, 6, 7, 8],
              [9, 10, 11, 12],
              [13, 14, 15, 16]])  # added some commas and array creation code

fig = plt.figure(figsize=(6, 3.2))

ax = fig.add_subplot(111)
ax.set_title('colorMap')
plt.imshow(H)
ax.set_aspect('equal')

cax = fig.add_axes([0.12, 0.1, 0.78, 0.8])
cax.get_xaxis().set_visible(False)
cax.get_yaxis().set_visible(False)
cax.patch.set_alpha(0)
cax.set_frame_on(False)
plt.colorbar(orientation='vertical')
plt.show()

Convert base class to derived class

No it is not possible. The only way that is possible is

static void Main(string[] args)
{
    BaseClass myBaseObject = new DerivedClass();
    DerivedClass myDerivedObject = myBaseObject as DerivedClass;

    myDerivedObject.MyDerivedProperty = true;
}

How do I create JavaScript array (JSON format) dynamically?

var student = [];
var obj = {
    'first_name': name,
    'last_name': name,
    'age': age,
}
student.push(obj);

Recover sa password

best answer written by Dmitri Korotkevitch:

Speaking of the installation, SQL Server 2008 allows you to set authentication mode (Windows or SQL Server) during the installation process. You will be forced to choose the strong password for sa user in the case if you choose sql server authentication mode during setup.

If you install SQL Server with Windows Authentication mode and want to change it, you need to do 2 different things:

  1. Go to SQL Server Properties/Security tab and change the mode to SQL Server authentication mode

  2. Go to security/logins, open SA login properties

a. Uncheck "Enforce password policy" and "Enforce password expiration" check box there if you decide to use weak password

b. Assign password to SA user

c. Open "Status" tab and enable login.

I don't need to mention that every action from above would violate security best practices that recommend to use windows authentication mode, have sa login disabled and use strong passwords especially for sa login.

jQuery get value of select onChange

Look for jQuery site

HTML:

<form>
  <input class="target" type="text" value="Field 1">
  <select class="target">
    <option value="option1" selected="selected">Option 1</option>
    <option value="option2">Option 2</option>
  </select>
</form>
<div id="other">
  Trigger the handler
</div>

JAVASCRIPT:

$( ".target" ).change(function() {
  alert( "Handler for .change() called." );
});

jQuery's example:

To add a validity test to all text input elements:

$( "input[type='text']" ).change(function() {
  // Check input( $( this ).val() ) for validity here
});

Where can I find the assembly System.Web.Extensions dll?

Your project is mostly likely targetting .NET Framework 4 Client Profile. Check the application tab in your project properties.

This question has a good answer on the different versions: Target framework, what does ".NET Framework ... Client Profile" mean?

How can you use optional parameters in C#?

Instead of default parameters, why not just construct a dictionary class from the querystring passed .. an implementation that is almost identical to the way asp.net forms work with querystrings.

i.e. Request.QueryString["a"]

This will decouple the leaf class from the factory / boilerplate code.


You also might want to check out Web Services with ASP.NET. Web services are a web api generated automatically via attributes on C# classes.

What's the best way to build a string of delimited items in Java?

using Dollar is simple as typing:

String joined = $(aCollection).join(",");

NB: it works also for Array and other data types

Implementation

Internally it uses a very neat trick:

@Override
public String join(String separator) {
    Separator sep = new Separator(separator);
    StringBuilder sb = new StringBuilder();

    for (T item : iterable) {
        sb.append(sep).append(item);
    }

    return sb.toString();
}

the class Separator return the empty String only the first time that it is invoked, then it returns the separator:

class Separator {

    private final String separator;
    private boolean wasCalled;

    public Separator(String separator) {
        this.separator = separator;
        this.wasCalled = false;
    }

    @Override
    public String toString() {
        if (!wasCalled) {
            wasCalled = true;
            return "";
        } else {
            return separator;
        }
    }
}

How to write specific CSS for mozilla, chrome and IE

Since you also have PHP in the tag, I'm going to suggest some server side options.

The easiest solution is the one most people suggest here. The problem I generally have with this, is that it can causes your CSS files or <style> tags to be up to 20 times bigger than your html documents and can cause browser slowdowns for parsing and processing tags that it can't understand -moz-border-radius vs -webkit-border-radius

The second best solution(i've found) is to have php output your actual css file i.e.

<link rel="stylesheet" type="text/css" href="mycss.php">

where

<?php
header("Content-Type: text/css");
if( preg_match("/chrome/", $_SERVER['HTTP_USER_AGENT']) ) {
  // output chrome specific css style
} else {
  // output default css style
}
?>

This allows you to create smaller easier to process files for the browser.

The best method I've found, is specific to Apache though. The method is to use mod_rewrite or mod_perl's PerlMapToStorageHandler to remap the URL to a file on the system based on the rendering engine.

say your website is http://www.myexample.com/ and it points to /srv/www/html. For chrome, if you ask for main.css, instead of loading /srv/www/html/main.css it checks to see if there is a /srv/www/html/main.webkit.css and if it exists, it dump that, else it'll output the main.css. For IE, it tries main.trident.css, for firefox it tries main.gecko.css. Like above, it allows me to create smaller, more targeted, css files, but it also allows me to use caching better, as the browser will attempt to redownload the file, and the web server will present the browser with proper 304's to tell it, you don't need to redownload it. It also allows my web developers a bit more freedom without for them having to write backend code to target platforms. I also have .js files being redirected to javascript engines as well, for main.js, in chrome it tries main.v8.js, in safari, main.nitro.js, in firefox, main.gecko.js. This allows for outputting of specific javascript that will be faster(less browser testing code/feature testing). Granted the developers don't have to target specific and can write a main.js and not make main.<js engine>.js and it'll load that normally. i.e. having a main.js and a main.jscript.js file means that IE gets the jscript one, and everyone else gets the default js, same with the css files.

SELECT *, COUNT(*) in SQLite

SELECT *, COUNT(*) FROM my_table is not what you want, and it's not really valid SQL, you have to group by all the columns that's not an aggregate.

You'd want something like

SELECT somecolumn,someothercolumn, COUNT(*) 
   FROM my_table 
GROUP BY somecolumn,someothercolumn

JavaScript chop/slice/trim off last character in string

If you want to do generic rounding of floats, instead of just trimming the last character:

var float1 = 12345.00,
    float2 = 12345.4567,
    float3 = 12345.982;

var MoreMath = {
    /**
     * Rounds a value to the specified number of decimals
     * @param float value The value to be rounded
     * @param int nrDecimals The number of decimals to round value to
     * @return float value rounded to nrDecimals decimals
     */
    round: function (value, nrDecimals) {
        var x = nrDecimals > 0 ? 10 * parseInt(nrDecimals, 10) : 1;
        return Math.round(value * x) / x;
    }
}

MoreMath.round(float1, 1) => 12345.0
MoreMath.round(float2, 1) => 12345.5
MoreMath.round(float3, 1) => 12346.0

EDIT: Seems like there exists a built in function for this, as Paolo points out. That solution is obviously much cleaner than mine. Use parseFloat followed by toFixed

Command-line Unix ASCII-based charting / plotting tool

feedgnuplot is another front end to gnuplot, which handles piping in data.

    $ seq 5 | awk '{print 2*$1, $1*$1}' |
      feedgnuplot --lines --points --legend 0 "data 0" --title "Test plot" --y2 1
                  --terminal 'dumb 80,40' --exit

                                     Test plot

     10 ++------+--------+-------+-------+-------+--------+-------+------*A 25
        +       +        +       +       +       +        +       +    **#+
        |       :        :       :       :       :        : data 0+**A*** |
        |       :        :       :       :       :        :       :** #   |
      9 ++.......................................................**.##....|
        |       :        :       :       :       :        :    ** :#      |
        |       :        :       :       :       :        :  **   #       |
        |       :        :       :       :       :        :**   ##:      ++ 20
      8 ++................................................A....#..........|
        |       :        :       :       :       :      **:   #   :       |
        |       :        :       :       :       :    **  : ##    :       |
        |       :        :       :       :       :  **    :#      :       |
        |       :        :       :       :       :**      B       :       |
      7 ++......................................**......##................|
        |       :        :       :       :    ** :    ##  :       :      ++ 15
        |       :        :       :       :  **   :   #    :       :       |
        |       :        :       :       :**     : ##     :       :       |
      6 ++..............................*A.......##.......................|
        |       :        :       :    ** :     ##:        :       :       |
        |       :        :       :  **   :    #  :        :       :       |
        |       :        :       :**     :  ##   :        :       :      ++ 10
      5 ++......................**........##..............................|
        |       :        :    ** :      #B       :        :       :       |
        |       :        :  **   :    ## :       :        :       :       |
        |       :        :**     :  ##   :       :        :       :       |
      4 ++...............A.......###......................................|
        |       :      **:     ##:       :       :        :       :       |
        |       :    **  :   ##  :       :       :        :       :      ++ 5
        |       :  **    : ##    :       :       :        :       :       |
        |       :**    ##B#      :       :       :        :       :       |
      3 ++.....**..####...................................................|
        |    **####      :       :       :       :        :       :       |
        |  **## :        :       :       :       :        :       :       |
        B**     +        +       +       +       +        +       +       +
      2 A+------+--------+-------+-------+-------+--------+-------+------++ 0
        1      1.5       2      2.5      3      3.5       4      4.5      5

Is JavaScript guaranteed to be single-threaded?

No.

I'm going against the crowd here, but bear with me. A single JS script is intended to be effectively single threaded, but this doesn't mean that it can't be interpreted differently.

Let's say you have the following code...

var list = [];
for (var i = 0; i < 10000; i++) {
  list[i] = i * i;
}

This is written with the expectation that by the end of the loop, the list must have 10000 entries which are the index squared, but the VM could notice that each iteration of the loop does not affect the other, and reinterpret using two threads.

First thread

for (var i = 0; i < 5000; i++) {
  list[i] = i * i;
}

Second thread

for (var i = 5000; i < 10000; i++) {
  list[i] = i * i;
}

I'm simplifying here, because JS arrays are more complicated then dumb chunks of memory, but if these two scripts are able to add entries to the array in a thread-safe way, then by the time both are done executing it'll have the same result as the single-threaded version.

While I'm not aware of any VM detecting parallelizable code like this, it seems likely that it could come into existence in the future for JIT VMs, since it could offer more speed in some situations.

Taking this concept further, it's possible that code could be annotated to let the VM know what to convert to multi-threaded code.

// like "use strict" this enables certain features on compatible VMs.
"use parallel";

var list = [];

// This string, which has no effect on incompatible VMs, enables threading on
// this loop.
"parallel for";
for (var i = 0; i < 10000; i++) {
  list[i] = i * i;
}

Since Web Workers are coming to Javascript, it's unlikely that this... uglier system will ever come into existence, but I think it's safe to say Javascript is single-threaded by tradition.

Is it possible to open a Windows Explorer window from PowerShell?

I came across this question looking for a way to open an Explorer window from PowerShell and also select a file. I'm adding this answer in case others come across it for the same reason.

To launch Explorer and select a file, use Invoke-Expression:

Invoke-Expression "explorer '/select,$filePath'"

There are probably other ways to do this, but this worked for me.