Programs & Examples On #Dial up

Network tools that simulate slow network connection


Try this FreeBSD based VMWare image. It also has an excellent how-to, purely free and stands up in 20 minutes.

Update: DummyNet also supports Linux, OSX and Windows by now

SQL Server Convert Varchar to Datetime

Try the below

select Convert(Varchar(50),yourcolumn,103) as Converted_Date from yourtbl

How to move all files including hidden files into parent directory via *

You can find a comprehensive set of solutions on this in UNIX & Linux's answer to How do you move all files (including hidden) from one directory to another?. It shows solutions in Bash, zsh, ksh93, standard (POSIX) sh, etc.

You can use these two commands together:

mv /path/subfolder/* /path/   # your current approach
mv /path/subfolder/.* /path/  # this one for hidden files

Or all together (thanks pfnuesel):

mv /path/subfolder/{.,}* /path/

Which expands to:

mv /path/subfolder/* /path/subfolder/.* /path/

(example: echo a{.,}b expands to a.b ab)

Note this will show a couple of warnings:

mv: cannot move ‘/path/subfolder/.’ to /path/.’: Device or resource busy
mv: cannot remove /path/subfolder/..’: Is a directory

Just ignore them: this happens because /path/subfolder/{.,}* also expands to /path/subfolder/. and /path/subfolder/.., which are the directory and the parent directory (See What do “.” and “..” mean when in a folder?).

If you want to just copy, you can use a mere:

cp -r /path/subfolder/. /path/
#                     ^
#                     note the dot!

This will copy all files, both normal and hidden ones, since /path/subfolder/. expands to "everything from this directory" (Source: How to copy with cp to include hidden files and hidden directories and their contents?)

How to pass in a react component into another react component to transclude the first component's content?

Note I provided a more in-depth answer here

Runtime wrapper:

It's the most idiomatic way.

const Wrapper = ({children}) => (

const App = () => <div>Hello</div>;

const WrappedApp = () => (

Note that children is a "special prop" in React, and the example above is syntactic sugar and is (almost) equivalent to <Wrapper children={<App/>}/>

Initialization wrapper / HOC

You can use an Higher Order Component (HOC). They have been added to the official doc recently.

// Signature may look fancy but it's just 
// a function that takes a component and returns a new component
const wrapHOC = (WrappedComponent) => (props) => (
    <div><WrappedComponent {...props}/></div>

const App = () => <div>Hello</div>;

const WrappedApp = wrapHOC(App);

This can lead to (little) better performances because the wrapper component can short-circuit the rendering one step ahead with shouldComponentUpdate, while in the case of a runtime wrapper, the children prop is likely to always be a different ReactElement and cause re-renders even if your components extend PureComponent.

Notice that connect of Redux used to be a runtime wrapper but was changed to an HOC because it permits to avoid useless re-renders if you use the pure option (which is true by default)

You should never call an HOC during the render phase because creating React components can be expensive. You should rather call these wrappers at initialization.

Note that when using functional components like above, the HOC version do not provide any useful optimisation because stateless functional components do not implement shouldComponentUpdate

More explanations here:

How to pass url arguments (query string) to a HTTP request on Angular?

You can use Url Parameters from the official documentation.

Example: this.httpClient.get(this.API, { params: new HttpParams().set('noCover', noCover) })

How do you access the element HTML from within an Angular attribute directive?

Base on @Mark answer, I add the constructor to directive and it work with me.

I share a sample to whom concern.

constructor(private el: ElementRef, private renderer: Renderer) {

TS file

@Directive({ selector: '[accordion]' })
export class AccordionDirective {

  constructor(private el: ElementRef, private renderer: Renderer) {

  @HostListener('click', ['$event']) onClick($event) {$event);


    var content = this.el.nativeElement.nextElementSibling;
    if ( {
      // accordion is currently open, so close it = null;
    } else {
      // accordion is currently closed, so open it = content.scrollHeight + "px";



<button accordion class="accordion">Accordian #1</button>
    <div class="accordion-content">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quas deleniti molestias necessitatibus quaerat quos incidunt! Quas officiis repellat dolore omnis nihil quo,
        ratione cupiditate! Sed, deleniti, recusandae! Animi, sapiente, nostrum?


How to align entire html body to the center?

Try this

body {
max-width: max-content;
margin: auto;

Freely convert between List<T> and IEnumerable<T>

Converting List<T> to IEnumerable<T>

List<T> implements IEnumerable<T> (and many other such as IList<T>, ICollection<T>) therefore there is no need to convert a List back to IEnumerable since it already a IEnumerable<T>.


public class Person
    public int Id { get; set; }
    public string Name { get; set; }

Person person1 = new Person() { Id = 1, Name = "Person 1" };
Person person2 = new Person() { Id = 2, Name = "Person 2" };
Person person3 = new Person() { Id = 3, Name = "Person 3" };

List<Person> people = new List<Person>() { person1, person2, person3 };

//Converting to an IEnumerable
IEnumerable<Person> IEnumerableList = people;

You can also use Enumerable.AsEnumerable() method

IEnumerable<Person> iPersonList = people.AsEnumerable();

Converting IEnumerable<T> to List<T>

IEnumerable<Person> OriginallyIEnumerable = new List<Person>() { person1, person2 };
List<Person> convertToList = OriginallyIEnumerable.ToList();

This is useful in Entity Framework.

How to pass an array into a SQL Server stored procedure

SQL Server 2008 (or newer)

First, in your database, create the following two objects:


CREATE PROCEDURE dbo.DoSomethingWithEmployees
  @List AS dbo.IDList READONLY


Now in your C# code:

// Obtain your list of ids to send, this is just an example call to a helper utility function
int[] employeeIds = GetEmployeeIds();

DataTable tvp = new DataTable();
tvp.Columns.Add(new DataColumn("ID", typeof(int)));

// populate DataTable from your List here
foreach(var id in employeeIds)

using (conn)
    SqlCommand cmd = new SqlCommand("dbo.DoSomethingWithEmployees", conn);
    cmd.CommandType = CommandType.StoredProcedure;
    SqlParameter tvparam = cmd.Parameters.AddWithValue("@List", tvp);
    // these next lines are important to map the C# DataTable object to the correct SQL User Defined Type
    tvparam.SqlDbType = SqlDbType.Structured;
    tvparam.TypeName = "dbo.IDList";
    // execute query, consume results, etc. here

SQL Server 2005

If you are using SQL Server 2005, I would still recommend a split function over XML. First, create a function:

   @List      VARCHAR(MAX),
   @Delimiter VARCHAR(255)
      ( SELECT Item = x.i.value('(./text())[1]', 'varchar(max)')
        FROM ( SELECT [XML] = CONVERT(XML, '<i>'
        + REPLACE(@List, @Delimiter, '</i><i>') + '</i>').query('.')
          ) AS a CROSS APPLY [XML].nodes('i') AS x(i) ) AS y

Now your stored procedure can just be:

CREATE PROCEDURE dbo.DoSomethingWithEmployees

  SELECT EmployeeID = Item FROM dbo.SplitInts(@List, ','); 

And in your C# code you just have to pass the list as '1,2,3,12'...

I find the method of passing through table valued parameters simplifies the maintainability of a solution that uses it and often has increased performance compared to other implementations including XML and string splitting.

The inputs are clearly defined (no one has to guess if the delimiter is a comma or a semi-colon) and we do not have dependencies on other processing functions that are not obvious without inspecting the code for the stored procedure.

Compared to solutions involving user defined XML schema instead of UDTs, this involves a similar number of steps but in my experience is far simpler code to manage, maintain and read.

In many solutions you may only need one or a few of these UDTs (User defined Types) that you re-use for many stored procedures. As with this example, the common requirement is to pass through a list of ID pointers, the function name describes what context those Ids should represent, the type name should be generic.

How to normalize a vector in MATLAB efficiently? Any related built-in function?

I took Mr. Fooz's code and also added Arlen's solution too and here are the timings that I've gotten for Octave:

clc; clear all;
V = rand(1024*1024*32,1);
N = 10;
tic; for i=1:N, V1 = V/norm(V);         end; toc % 7.0 s
tic; for i=1:N, V2 = V/sqrt(sum(V.*V)); end; toc % 6.4 s
tic; for i=1:N, V3 = V/sqrt(V'*V);      end; toc % 5.5 s
tic; for i=1:N, V4 = V/sqrt(sum(V.^2)); end; toc % 6.6 s
tic; for i=1:N, V1 = V/norm(V);         end; toc % 7.1 s
tic; for i=1:N, d = 1/norm(V); V1 = V*d;end; toc % 4.7 s

Then, because of something I'm currently looking at, I tested out this code for ensuring that each row sums to 1:

clc; clear all;
m = 2048;
V = rand(m);
N = 100;
tic; for i=1:N, V1 = V ./ (sum(V,2)*ones(1,m));                end; toc % 8.2 s
tic; for i=1:N, V2 = bsxfun(@rdivide, V, sum(V,2));            end; toc % 5.8 s
tic; for i=1:N, V3 = bsxfun(@rdivide, V, V*ones(m,1));         end; toc % 5.7 s
tic; for i=1:N, V4 = V ./ (V*ones(m,m));                       end; toc % 77.5 s
tic; for i=1:N, d = 1./sum(V,2);V5 = bsxfun(@times, V, d);     end; toc % 2.83 s
tic; for i=1:N, d = 1./(V*ones(m,1));V6 = bsxfun(@times, V, d);end; toc % 2.75 s
tic; for i=1:N, V1 = V ./ (sum(V,2)*ones(1,m));                end; toc % 8.2 s

How to increase IDE memory limit in IntelliJ IDEA on Mac?

For IDEA 13 and OS X 10.9 Mavericks, the correct paths are:

Original: /Applications/IntelliJ IDEA

Copy to: ~/Library/Preferences/IntelliJIdea13/idea.vmoptions

Python Array with String Indices

What you want is called an associative array. In python these are called dictionaries.

Dictionaries are sometimes found in other languages as “associative memories” or “associative arrays”. Unlike sequences, which are indexed by a range of numbers, dictionaries are indexed by keys, which can be any immutable type; strings and numbers can always be keys.

myDict = {}
myDict["john"] = "johns value"
myDict["jeff"] = "jeffs value"

Alternative way to create the above dict:

myDict = {"john": "johns value", "jeff": "jeffs value"}

Accessing values:

print(myDict["jeff"]) # => "jeffs value"

Getting the keys (in Python v2):

print(myDict.keys()) # => ["john", "jeff"]

In Python 3, you'll get a dict_keys, which is a view and a bit more efficient (see views docs and PEP 3106 for details).

print(myDict.keys()) # => dict_keys(['john', 'jeff']) 

If you want to learn about python dictionary internals, I recommend this ~25 min video presentation: It's called the "The Mighty Dictionary".

How to check whether an array is empty using PHP?

$status = "";

$new_array = array();

  $status = "1";   // not a blank array
  $status = "0";   // blank array

JPA CascadeType.ALL does not delete orphans

I had the same problem and I wondered why this condition below did not delete the orphans. The list of dishes were not deleted in Hibernate (5.0.3.Final) when I executed a named delete query:

@OneToMany(mappedBy = "menuPlan", cascade = CascadeType.ALL, orphanRemoval = true)
private List<Dish> dishes = new ArrayList<>();

Then I remembered that I must not use a named delete query, but the EntityManager. As I used the EntityManager.find(...) method to fetch the entity and then EntityManager.remove(...) to delete it, the dishes were deleted as well.

Python assigning multiple variables to same value? list behavior

Yes, that's the expected behavior. a, b and c are all set as labels for the same list. If you want three different lists, you need to assign them individually. You can either repeat the explicit list, or use one of the numerous ways to copy a list:

b = a[:] # this does a shallow copy, which is good enough for this case
import copy
c = copy.deepcopy(a) # this does a deep copy, which matters if the list contains mutable objects

Assignment statements in Python do not copy objects - they bind the name to an object, and an object can have as many labels as you set. In your first edit, changing a[0], you're updating one element of the single list that a, b, and c all refer to. In your second, changing e, you're switching e to be a label for a different object (4 instead of 3).

Using SSH keys inside docker container

You can pass the authorised keys in to your container using a shared folder and set permissions using a docker file like this:

FROM ubuntu:16.04
RUN apt-get install -y openssh-server
RUN mkdir /var/run/sshd
RUN cp /root/auth/ /root/.ssh/authorized_keys
RUN rm -f /root/auth
RUN chmod 700 /root/.ssh
RUN chmod 400 /root/.ssh/authorized_keys
RUN chown root. /root/.ssh/authorized_keys
CMD /usr/sbin/sshd -D

And your docker run contains something like the following to share an auth directory on the host (holding the authorised_keys) with the container then open up the ssh port which will be accessable through port 7001 on the host.

-d -v /home/thatsme/dockerfiles/auth:/root/auth -–publish=

You may want to look at which appears to be another way to open a shell on a container and execute commands within a container.

How do I concatenate strings with variables in PowerShell?

This will get all dll files and filter ones that match a regex of your directory structure.

Get-ChildItem C:\code -Recurse -filter "*.dll" | where { $ -match 'C:\\code\\myproj.\\bin\\debug'}

If you just want the path, not the object you can add | select fullname to the end like this:

Get-ChildItem C:\code -Recurse -filter "*.dll" | where { $ -match 'C:\\code\\myproj.\\bin\\debug'} | select fullname

Div Scrollbar - Any way to style it?

There's also the iScroll project which allows you to style the scrollbars plus get it to work with touch devices.

How can I find the method that called the current method?

A quick recap of the 2 approaches with speed comparison being the important part.

Determining the caller at compile-time

static void Log(object message, 
[CallerMemberName] string memberName = "",
[CallerFilePath] string fileName = "",
[CallerLineNumber] int lineNumber = 0)
    // we'll just use a simple Console write for now    
    Console.WriteLine("{0}({1}):{2} - {3}", fileName, lineNumber, memberName, message);

Determining the caller using the stack

static void Log(object message)
    // frame 1, true for source info
    StackFrame frame = new StackFrame(1, true);
    var method = frame.GetMethod();
    var fileName = frame.GetFileName();
    var lineNumber = frame.GetFileLineNumber();

    // we'll just use a simple Console write for now    
    Console.WriteLine("{0}({1}):{2} - {3}", fileName, lineNumber, method.Name, message);

Comparison of the 2 approaches

Time for 1,000,000 iterations with Attributes: 196 ms
Time for 1,000,000 iterations with StackTrace: 5096 ms

So you see, using the attributes is much, much faster! Nearly 25x faster in fact.

Using any() and all() to check if a list contains one set of values or another

Generally speaking:

all and any are functions that take some iterable and return True, if

  • in the case of all(), no values in the iterable are falsy;
  • in the case of any(), at least one value is truthy.

A value x is falsy iff bool(x) == False. A value x is truthy iff bool(x) == True.

Any non-booleans in the iterable will be fine — bool(x) will coerce any x according to these rules: 0, 0.0, None, [], (), [], set(), and other empty collections will yield False, anything else True. The docstring for bool uses the terms 'true'/'false' for 'truthy'/'falsy', and True/False for the concrete boolean values.

In your specific code samples:

You misunderstood a little bit how these functions work. Hence, the following does something completely not what you thought:

if any(foobars) == big_foobar:

...because any(foobars) would first be evaluated to either True or False, and then that boolean value would be compared to big_foobar, which generally always gives you False (unless big_foobar coincidentally happened to be the same boolean value).

Note: the iterable can be a list, but it can also be a generator/generator expression (˜ lazily evaluated/generated list) or any other iterator.

What you want instead is:

if any(x == big_foobar for x in foobars):

which basically first constructs an iterable that yields a sequence of booleans—for each item in foobars, it compares the item to big_foobar and emits the resulting boolean into the resulting sequence:

tmp = (x == big_foobar for x in foobars)

then any walks over all items in tmp and returns True as soon as it finds the first truthy element. It's as if you did the following:

In [1]: foobars = ['big', 'small', 'medium', 'nice', 'ugly']                                        

In [2]: big_foobar = 'big'                                                                          

In [3]: any(['big' == big_foobar, 'small' == big_foobar, 'medium' == big_foobar, 'nice' == big_foobar, 'ugly' == big_foobar])        
Out[3]: True

Note: As DSM pointed out, any(x == y for x in xs) is equivalent to y in xs but the latter is more readable, quicker to write and runs faster.

Some examples:

In [1]: any(x > 5 for x in range(4))
Out[1]: False

In [2]: all(isinstance(x, int) for x in range(10))
Out[2]: True

In [3]: any(x == 'Erik' for x in ['Erik', 'John', 'Jane', 'Jim'])
Out[3]: True

In [4]: all([True, True, True, False, True])
Out[4]: False

See also:

How can I add raw data body to an axios request?

The only solution I found that would work is the transformRequest property which allows you to override the extra data prep axios does before sending off the request.

        method: 'post',
        url: '',
        data: {},
        headers: {
            'Content-Type': 'application/x-www-form-urlencoded',
        transformRequest: [(data, header) => {
            data = 'grant_type=client_credentials'
            return data

Entity Framework Code First - two Foreign Keys from same table

You can try this too:

public class Match
    public int MatchId { get; set; }

    [ForeignKey("HomeTeam"), Column(Order = 0)]
    public int? HomeTeamId { get; set; }
    [ForeignKey("GuestTeam"), Column(Order = 1)]
    public int? GuestTeamId { get; set; }

    public float HomePoints { get; set; }
    public float GuestPoints { get; set; }
    public DateTime Date { get; set; }

    public virtual Team HomeTeam { get; set; }
    public virtual Team GuestTeam { get; set; }

When you make a FK column allow NULLS, you are breaking the cycle. Or we are just cheating the EF schema generator.

In my case, this simple modification solve the problem.

SSL cert "err_cert_authority_invalid" on mobile chrome only

I solved my problem with this commands:

cat __mydomain_com.crt > __mydomain_com_combine.crt

and after:

cat __mydomain_com_combine.crt COMODORSADomainValidationSecureServerCA.crt 
COMODORSAAddTrustCA.crt AddTrustExternalCARoot.crt > mydomain.pem

And in my domain nginx .conf I put on the server 443:

ssl_certificate          ssl/mydomain.pem;
ssl_certificate_key      ssl/mydomain.private.key;

I don't forget restart your "Nginx"

service nginx restart

MySQL 8.0 - Client does not support authentication protocol requested by server; consider upgrading MySQL client

I just run into this problem too, with all the MySQL re-config mentioned above the error still appears. It turns out that I misspelled the database name.

So be sure you're connecting with the right database name especially the case.

How can I send an inner <div> to the bottom of its parent <div>?

This is one way

<div style="position: relative; 
            width: 200px; 
            height: 150px; 
            border: 1px solid black;">

    <div style="position: absolute; 
                bottom: 0; 
                width: 100%; 
                height: 50px; 
                border: 1px solid red;">

But because the inner div is positioned absolutely, you'll always have to worry about other content in the outer div overlapping it (and you'll always have to set fixed heights).

If you can do it, it's better to make that inner div the last DOM object in your outer div and have it set to "clear: both".

Simple parse JSON from URL on Android and display in listview

I would suggest using the JSONParser class. It's very easy to use.

public class JSONParser {

static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {


// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHttpRequest(String url, String method,
        List<NameValuePair> params) throws IOException {

    // Making HTTP request
    try {

        // check for request method
        if(method == "POST"){
            // request method is POST
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(params));

            HttpResponse httpResponse = httpClient.execute(httpPost);

            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            // request method is GET
            DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
            String paramString = URLEncodedUtils.format(params, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

    } catch (UnsupportedEncodingException e) {
    } catch (ClientProtocolException e) {
    } catch (Exception ex) {
        Log.d("Networking", ex.getLocalizedMessage());
        throw new IOException("Error connecting");

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());

    // return JSON String
    return jObj;


Then in your application, create an instance of this class. You may want to pass the constructor 'GET' or 'POST' if desired.

public JSONParser jsonParser = new JSONParser();

try {

    // Building Parameters ( you can pass as many parameters as you want)
    List<NameValuePair> params = new ArrayList<NameValuePair>();

    params.add(new BasicNameValuePair("name", name));
    params.add(new BasicNameValuePair("age", 25));

    // Getting JSON Object
    JSONObject json = jsonParser.makeHttpRequest(YOUR_URL, "POST", params);
} catch (JSONException e) {

Using "If cell contains #N/A" as a formula condition.

"N/A" is not a string it is an error, try this:


you have to place this fomula in cell B1 so it will get the value of your formula

Where can I find error log files?

What OS you are using and which Webserver? On Linux and Apache you can find the apache error_log in /var/log/apache2/

Why should I use core.autocrlf=true in Git?

For me.

Edit .gitattributes file.


*.dll binary

Then everything goes well.

PHP, get file name without file extension

This return only filename without any extension in 1 row:

$path = "/etc/sudoers.php";    
print array_shift(explode(".", basename($path)));
// will print "sudoers"

$file = "file_name.php";    
print array_shift(explode(".", basename($file)));
// will print "file_name"

How do I create a dictionary with keys from a list and values defaulting to (say) zero?

d = dict.fromkeys(a, 0)

a is the list, 0 is the default value. Pay attention not to set the default value to some mutable object (i.e. list or dict), because it will be one object used as value for every key in the dictionary (check here for a solution for this case). Numbers/strings are safe.

Working Copy Locked

error "working copy locked", Just follow the steps :

  1. In which directory you are getting error on update
  2. Go to its parent directory
  3. In parent directory go to ".svn" hidden directory
  4. Remove file with name "lock"
  5. Clean up and Done

You can update the svn properly without error

VBA test if cell is in a range

Here is another option to see if a cell exists inside a range. In case you have issues with the Intersect solution as I did.

If InStr(range("NamedRange").Address, range("IndividualCell").Address) > 0 Then
    'The individual cell exists in the named range
    'The individual cell does not exist in the named range
End If

InStr is a VBA function that checks if a string exists within another string.

Flutter does not find android sdk

I have got following issue on Flutter Doctor command.

X Android SDK file not found: ..\Android\sdk\platforms\android-28\android.jar.

to fix this just go to Tools=> Android Sdk =>Update Sdk Platform for which issue is there.(I installed SDK 28).

check flutter document for this issue

How to initialize array to 0 in C?

Global variables and static variables are automatically initialized to zero. If you have simply

char ZEROARRAY[1024];

at global scope it will be all zeros at runtime. But actually there is a shorthand syntax if you had a local array. If an array is partially initialized, elements that are not initialized receive the value 0 of the appropriate type. You could write:

char ZEROARRAY[1024] = {0};

The compiler would fill the unwritten entries with zeros. Alternatively you could use memset to initialize the array at program startup:

memset(ZEROARRAY, 0, 1024);

That would be useful if you had changed it and wanted to reset it back to all zeros.

Bootstrap fullscreen layout with 100% height

<section class="min-vh-100 d-flex align-items-center justify-content-center py-3">
  <div class="container">
    <div class="row justify-content-between align-items-center">

Why am I suddenly getting a "Blocked loading mixed active content" issue in Firefox?

Simply changing HTTP to HTTPS solved this issue for me.


<script src=""></script>


<script src=""></script>

How to write to Console.Out during execution of an MSTest test

I found a solution of my own. I know that Andras answer is probably the most consistent with MSTEST, but I didn't feel like refactoring my code.

public void OneIsOne()
    using (ConsoleRedirector cr = new ConsoleRedirector())
        Assert.IsFalse(cr.ToString().Contains("New text"));
        /* call some method that writes "New text" to stdout */
        Assert.IsTrue(cr.ToString().Contains("New text"));

The disposable ConsoleRedirector is defined as:

internal class ConsoleRedirector : IDisposable
    private StringWriter _consoleOutput = new StringWriter();
    private TextWriter _originalConsoleOutput;
    public ConsoleRedirector()
        this._originalConsoleOutput = Console.Out;
    public void Dispose()
    public override string ToString()
        return this._consoleOutput.ToString();

Could not load file or assembly 'System.Web.WebPages.Razor, Version=

Apologies in advance for this lo-tech suggestion, but another option, which finally worked for me after battling NuGet for several hours, is to re-create a new empty project, Web API in my case, and just copy the guts of your old, now-broken project into the new one. Took me about 15 minutes.

Simple excel find and replace for formulas

Use the find and replace command accessible through ctrl+h, make sure you are searching through the functions of the cells. You can then wildcards to accommodate any deviations of the formula. * for # wildcards, ? for charcter wildcards, and ~? or ~* to search for ? or *.

How to do while loops with multiple conditions

while not condition1 or not condition2 or val == -1:

But there was nothing wrong with your original of using an if inside of a while True.

Is there a "theirs" version of "git merge -s ours"?

Older versions of git allowed you to use the "theirs" merge strategy:

git pull --strategy=theirs remote_branch

But this has since been removed, as explained in this message by Junio Hamano (the Git maintainer). As noted in the link, instead you would do this:

git fetch origin
git reset --hard origin

Beware, though, that this is different than an actual merge. Your solution is probably the option you're really looking for.

No suitable records were found verify your bundle identifier is correct

If after you confirm your Bundle ID's match across App Store Connect, Apple Developer Portal, and Xcode and you are still having issues try this:

Remove the Apple ID associated with the Bundle ID you're experiencing issues with from your Accounts list in Xcode (Menu Bar -> Xcode -> Preferences -> Accounts). Then, add the Apple ID back to the Accounts list in Xcode.

How to convert minutes to hours/minutes and add various time values together using jQuery?

Alternated to support older browsers.

function minutesToHHMM (mins, twentyFour) {
  var h = Math.floor(mins / 60);
  var m = mins % 60;
  m = m < 10 ? '0' + m : m;

  if (twentyFour === 'EU') {
    h = h < 10 ? '0' + h : h;
    return h+':'+m;
  } else {
    var a = 'am';
    if (h >= 12) a = 'pm';
    if (h > 12) h = h - 12;
    return h+':'+m+a;

Datatable select with multiple conditions

Try this,
I think ,this is one of the simple solutions.

int rowIndex = table.Rows.IndexOf(table.Select("A = 'foo' AND B = 'bar' AND C = 'baz'")[0]);
string strD= Convert.ToString(table.Rows[rowIndex]["D"]);

Make sure,combination of values for column A, B and C is unique in the datatable.

Generic XSLT Search and Replace template

Here's one way in XSLT 2

<?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="2.0" xmlns:xsl="">   <xsl:template match="@*|node()">     <xsl:copy>       <xsl:apply-templates select="@*|node()"/>     </xsl:copy>   </xsl:template>   <xsl:template match="text()">     <xsl:value-of select="translate(.,'&quot;','''')"/>   </xsl:template> </xsl:stylesheet> 

Doing it in XSLT1 is a little more problematic as it's hard to get a literal containing a single apostrophe, so you have to resort to a variable:

<xsl:stylesheet version="1.0" xmlns:xsl="">   <xsl:template match="@*|node()">     <xsl:copy>       <xsl:apply-templates select="@*|node()"/>     </xsl:copy>   </xsl:template>   <xsl:variable name="apos">'</xsl:variable>   <xsl:template match="text()">     <xsl:value-of select="translate(.,'&quot;',$apos)"/>   </xsl:template> </xsl:stylesheet> 

exporting multiple modules in react.js

You can have only one default export which you declare like:

export default App; or export default class App extends React.Component {...

and later do import App from './App'

If you want to export something more you can use named exports which you declare without default keyword like:

export {


export About;
export Contact;


export const About = class About extends React.Component {....
export const Contact = () => (<div> ... </div>);

and later you import them like:

import App, { About, Contact } from './App';


There is a mistake in the tutorial as it is not possible to make 3 default exports in the same main.js file. Other than that why export anything if it is no used outside the file?. Correct main.js :

import React from 'react';
import ReactDOM from 'react-dom';
import { Router, Route, Link, browserHistory, IndexRoute  } from 'react-router'

class App extends React.Component {

class Home extends React.Component {

class About extends React.Component {

class Contact extends React.Component {

   <Router history = {browserHistory}>
      <Route path = "/" component = {App}>
         <IndexRoute component = {Home} />
         <Route path = "home" component = {Home} />
         <Route path = "about" component = {About} />
         <Route path = "contact" component = {Contact} />

), document.getElementById('app'))


another thing is that this tutorial is based on react-router-V3 which has different api than v4.

How to open generated pdf using jspdf in new window

This works for me!!!

When you specify window features, it will open in a new window

Just like :,"_blank","top=100,left=200,width=1000,height=500");

How to tell if UIViewController's view is visible

I needed this to check if the view controller is the current viewed controller, I did it via checking if there's any presented view controller or pushed through the navigator, I'm posting it in case anyone needed such a solution:

if presentedViewController != nil || navigationController?.topViewController != self {
      //Viewcontroller isn't viewed
     // Now your viewcontroller is being viewed 

How to move Jenkins from one PC to another

Sometimes we may not have access to a Jenkins machine to copy a folder directly into another Jenkins instance. So I wrote a menu driven utility which uses Jenkins REST API calls to install plugins and jobs from one Jenkins instance to another.

For plugin migration:

  1. GET request: {SOURCE_JENKINS_SERVER}/pluginManager/api/json?depth=1 will get you the list of plugins installed with their version.
  2. You can send a POST request with the following parameters to install these plugins.

    data=`<jenkins><install plugin="{PLUGIN_NAME}@latest"/></jenkins>` (where, latest will fetch the latest version of the plugin_name)
    auth=`(destination_jenkins_username, destination_jenkins_password)`
    header=`{crumb_field:crumb_value,"Content-Type":"application/xml”}` (where crumb_field=Jenkins-Crumb and get crumb value using API call {DESTINATION_JENKINS_SERVER}/crumbIssuer/api/json

For job migration:

  1. You can get the list of jobs installed on {SOURCE_JENKINS_URL} using a REST call, {SOURCE_JENKINS_URL}/view/All/api/json
  2. Then you can get each job config.xml file from the jobs on {SOURCE_JENKINS_URL} using the job URL {SOURCE_JENKINS_URL}/job/{JOB_NAME}.
  3. Use this config.xml file to POST the content of the XML file on {DESTINATION_JENKINS_URL} and that will create a job on {DESTINATION_JENKINS_URL}.

I have created a menu-driven utility in Python which asks the user to start plugin or Jenkins migration and uses Jenkins REST API calls to do it.

You can refer the JenkinsMigration.docx from this URL

Replace String in all files in Eclipse

Strange but it is a two step task:

  1. Search what you want
  2. In the search tab right click and select replace , or replace all:

A demo at:

Comparing two java.util.Dates to see if they are in the same day


As for adding a dependency, I'm afraid the java.util.Date & .Calendar really are so bad that the first thing I do to any new project is add the Joda-Time library. In Java 8 you can use the new java.time package, inspired by Joda-Time.

The core of Joda-Time is the DateTime class. Unlike java.util.Date, it understands its assigned time zone (DateTimeZone). When converting from j.u.Date, assign a zone.

DateTimeZone zone = DateTimeZone.forID( "America/Montreal" );
DateTime dateTimeQuébec = new DateTime( date , zone );


One way to verify if two date-times land on the same date is to convert to LocalDate objects.

That conversion depends on the assigned time zone. To compare LocalDate objects, they must have been converted with the same zone.

Here is a little utility method.

static public Boolean sameDate ( DateTime dt1 , DateTime dt2 )
    LocalDate ld1 = new LocalDate( dt1 );
    // LocalDate determination depends on the time zone.
    // So be sure the date-time values are adjusted to the same time zone.
    LocalDate ld2 = new LocalDate( dt2.withZone( dt1.getZone() ) );
    Boolean match = ld1.equals( ld2 );
    return match;

Better would be another argument, specifying the time zone rather than assuming the first DateTime object’s time zone should be used.

static public Boolean sameDate ( DateTimeZone zone , DateTime dt1 , DateTime dt2 )
    LocalDate ld1 = new LocalDate( dt1.withZone( zone ) );
    // LocalDate determination depends on the time zone.
    // So be sure the date-time values are adjusted to the same time zone.
    LocalDate ld2 = new LocalDate( dt2.withZone( zone ) );
    return ld1.equals( ld2 );

String Representation

Another approach is to create a string representation of the date portion of each date-time, then compare strings.

Again, the assigned time zone is crucial.

DateTimeFormatter formatter =;  // Static method.
String s1 = formatter.print( dateTime1 );
String s2 = formatter.print( dateTime2.withZone( dt1.getZone() )  );
Boolean match = s1.equals( s2 );
return match;

Span of Time

The generalized solution is to define a span of time, then ask if the span contains your target. This example code is in Joda-Time 2.4. Note that the "midnight"-related classes are deprecated. Instead use the withTimeAtStartOfDay method. Joda-Time offers three classes to represent a span of time in various ways: Interval, Period, and Duration.

Using the "Half-Open" approach where the beginning of the span is inclusive and the ending exclusive.

The time zone of the target can be different than the time zone of the interval.

DateTimeZone timeZone = DateTimeZone.forID( "Europe/Paris" );
DateTime target = new DateTime( 2012, 3, 4, 5, 6, 7, timeZone );
DateTime start = timeZone ).withTimeAtStartOfDay();
DateTime stop = start.plusDays( 1 ).withTimeAtStartOfDay();
Interval interval = new Interval( start, stop );
boolean containsTarget = interval.contains( target );


Java 8 and later comes with the java.time framework. Inspired by Joda-Time, defined by JSR 310, and extended by the ThreeTen-Extra project. See Tutorial.

The makers of Joda-Time have instructed us all to move to java.time as soon as is convenient. In the meantime Joda-Time continues as an actively maintained project. But expect future work to occur only in java.time and ThreeTen-Extra rather than Joda-Time.

To summarize java.time in a nutshell… An Instant is a moment on the timeline in UTC. Apply a time zone (ZoneId) to get a ZonedDateTime object. To move off the timeline, to get the vague indefinite idea of a date-time, use the "local" classes: LocalDateTime, LocalDate, LocalTime.

The logic discussed in the Joda-Time section of this Answer applies to java.time.

The old java.util.Date class has a new toInstant method for conversion to java.time.

Instant instant = yourJavaUtilDate.toInstant(); // Convert into java.time type.

Determining a date requires a time zone.

ZoneId zoneId = ZoneId.of( "America/Montreal" );

We apply that time zone object to the Instant to obtain a ZonedDateTime. From that we extract a date-only value (a LocalDate) as our goal is to compare dates (not hours, minutes, etc.).

ZonedDateTime zdt1 = ZonedDateTime.ofInstant( instant , zoneId );
LocalDate localDate1 = LocalDate.from( zdt1 );

Do the same to the second java.util.Date object we need for comparison. I’ll just use the current moment instead.

ZonedDateTime zdt2 = zoneId );
LocalDate localDate2 = LocalDate.from( zdt2 );

Use the special isEqual method to test for the same date value.

Boolean sameDate = localDate1.isEqual( localDate2 );

Why is using the JavaScript eval function a bad idea?

Unless you are 100% sure that the code being evaluated is from a trusted source (usually your own application) then it's a surefire way of exposing your system to a cross-site scripting attack.

NodeJS - What does "socket hang up" actually mean?

Another case worth mentioning (for Linux and OS X) is that if you use a library like https for performing the requests, or if you pass https://... as a URL of the locally served instance, you will be using port 443 which is a reserved private port and you might be ending up in Socket hang up or ECONNREFUSED errors.

Instead, use port 3000, f.e., and do an http request.

How do I read a resource file from a Java jar file?

You don't say if this is a desktop or web app. I would use the getResourceAsStream() method from an appropriate ClassLoader if it's a desktop or the Context if it's a web app.

How to use GNU Make on Windows?

Here's how I got it to work:

  copy c:\MinGW\bin\mingw32-make.exe c:\MinGW\bin\make.exe

Then I am able to open a command prompt and type make:

  make: *** No targets specified and no makefile found.  Stop.

Which means it's working now!

Display MessageBox in ASP

Here is one way of doing it:

       Dim message    
       message = "This is my message"
       Response.Write("<script language=VBScript>MsgBox """ + message + """</script>") 

Creating C formatted strings (not printing them)

If you have the code to log_out(), rewrite it. Most likely, you can do:

static FILE *logfp = ...;

void log_out(const char *fmt, ...)
    va_list args;

    va_start(args, fmt);
    vfprintf(logfp, fmt, args);

If there is extra logging information needed, that can be printed before or after the message shown. This saves memory allocation and dubious buffer sizes and so on and so forth. You probably need to initialize logfp to zero (null pointer) and check whether it is null and open the log file as appropriate - but the code in the existing log_out() should be dealing with that anyway.

The advantage to this solution is that you can simply call it as if it was a variant of printf(); indeed, it is a minor variant on printf().

If you don't have the code to log_out(), consider whether you can replace it with a variant such as the one outlined above. Whether you can use the same name will depend on your application framework and the ultimate source of the current log_out() function. If it is in the same object file as another indispensable function, you would have to use a new name. If you cannot work out how to replicate it exactly, you will have to use some variant like those given in other answers that allocates an appropriate amount of memory.

void log_out_wrapper(const char *fmt, ...)
    va_list args;
    size_t  len;
    char   *space;

    va_start(args, fmt);
    len = vsnprintf(0, 0, fmt, args);
    if ((space = malloc(len + 1)) != 0)
         va_start(args, fmt);
         vsnprintf(space, len+1, fmt, args);
    /* else - what to do if memory allocation fails? */

Obviously, you now call the log_out_wrapper() instead of log_out() - but the memory allocation and so on is done once. I reserve the right to be over-allocating space by one unnecessary byte - I've not double-checked whether the length returned by vsnprintf() includes the terminating null or not.

Handling ExecuteScalar() when no results are returned

Try this

sql = "select username from usermst where userid=2"

string getusername = Convert.ToString(command.ExecuteScalar());

How to change the Spyder editor background to dark?

Yes, that's the intuitive answer. Nothing in Spyder is intuitive. Go to Preferences/Editor and select the scheme you want. Then go to Preferences/Syntax Coloring and adjust the colors if you want to. tcebob

Format the date using Ruby on Rails

@CMW's answer is bang on the money. I've added this answer as an example of how to configure an initializer so that both Date and Time objects get the formatting


date_formats = {
  concise: '%d-%b-%Y' # 13-Jan-2014

Time::DATE_FORMATS.merge! date_formats
Date::DATE_FORMATS.merge! date_formats

Also the following two commands will iterate through all the DATE_FORMATS in your current environment, and display today's date and time in each format:

Date::DATE_FORMATS.keys.each{|k| puts [k,].join(':- ')}
Time::DATE_FORMATS.keys.each{|k| puts [k,].join(':- ')}

Get the device width in javascript

Just as an FYI, there is a library called breakpoints which detects the max-width as set in CSS and allows you to use it in JS if-else conditions using <=, <, >, >= and == signs. I found it quite useful. The payload size is under 3 KB.

Why does only the first line of this Windows batch file execute but all three lines execute in a command shell?

Try writing the following batch file and executing it:

Echo one
Echo two
Echo three

Only the first two lines get executed. But if you type "exit" at the command prompt, the next two lines are processed. It's a shell loading another.

To be sure that this is not what is happening in your script, just type "exit" when the first command ends.


How to read and write INI file with Python3?

Here's a complete read, update and write example.

Input file, test.ini

string_val = hello
bool_val = false
int_val = 11
pi_val = 3.14

Working code.

    from configparser import ConfigParser
except ImportError:
    from ConfigParser import ConfigParser  # ver. < 3.0

# instantiate
config = ConfigParser()

# parse existing file'test.ini')

# read values from a section
string_val = config.get('section_a', 'string_val')
bool_val = config.getboolean('section_a', 'bool_val')
int_val = config.getint('section_a', 'int_val')
float_val = config.getfloat('section_a', 'pi_val')

# update existing value
config.set('section_a', 'string_val', 'world')

# add a new section and some values
config.set('section_b', 'meal_val', 'spam')
config.set('section_b', 'not_found_val', '404')

# save to a file
with open('test_update.ini', 'w') as configfile:

Output file, test_update.ini

string_val = world
bool_val = false
int_val = 11
pi_val = 3.14

meal_val = spam
not_found_val = 404

The original input file remains untouched.

How to transform currentTimeMillis to a readable date format?

There is a simpler way in Android


Moreover, Date is deprecated, so use DateFormat class.

   DateFormat.getDateInstance().format(new Date(0));  
   DateFormat.getDateTimeInstance().format(new Date(0));  
   DateFormat.getTimeInstance().format(new Date(0));  

The above three lines will give:

Dec 31, 1969  
Dec 31, 1969 4:00:00 PM  
4:00:00 PM  12:00:00 AM

HTTP Status 500 - Error instantiating servlet class pkg.coreServlet

Have you closed the < web-app > tag in your web.xml? From what you have posted, the closing tag seems to be missing.

Importing Excel spreadsheet data into another Excel spreadsheet containing VBA

Data can be pulled into an excel from another excel through Workbook method or External reference or through Data Import facility.

If you want to read or even if you want to update another excel workbook, these methods can be used. We may not depend only on VBA for this.

For more info on these techniques, please click here to refer the article

How to gettext() of an element in Selenium Webdriver

You need to print the result of the getText(). You're currently printing the object TxtBoxContent.

getText() will only get the inner text of an element. To get the value, you need to use getAttribute().

WebElement TxtBoxContent = driver.findElement(;
System.out.println("Printing " + TxtBoxContent.getAttribute("value"));

Determine if Android app is being used for the first time

I like to have an "update count" in my shared preferences. If it's not there (or default zero value) then this is my app's "first use".

private static final int UPDATE_COUNT = 1;    // Increment this on major change
if (sp.getInt("updateCount", 0) == 0) {
    // first use
} else if (sp.getInt("updateCount", 0) < UPDATE_COUNT) {
    // Pop up dialog telling user about new features
sp.edit().putInt("updateCount", UPDATE_COUNT);

So now, whenever there's an update to the app that users should know about, I increment UPDATE_COUNT

TypeError: 'tuple' object does not support item assignment when swapping values

Evaluating "1,2,3" results in (1, 2, 3), a tuple. As you've discovered, tuples are immutable. Convert to a list before processing.

Store JSON object in data attribute in HTML jQuery

This is how it worked for me.


var my_object ={"Super Hero":["Iron Man", "Super Man"]};


Encode the stringified object with encodeURIComponent() and set as attribute:

var data_str = encodeURIComponent(JSON.stringify(my_object));


To get the value as an object, parse the decoded, with decodeURIComponent(), attribute value:

var data_str = $("div#mydiv").attr("data-hero");
var my_object = JSON.parse(decodeURIComponent(data_str));

Gradient of n colors ranging from color 1 and color 2

colorRampPalette could be your friend here:

colfunc <- colorRampPalette(c("black", "white"))
# [1] "#000000" "#1C1C1C" "#383838" "#555555" "#717171" "#8D8D8D" "#AAAAAA"
# [8] "#C6C6C6" "#E2E2E2" "#FFFFFF"

And just to show it works:


enter image description here

Android: Rotate image in imageview by an angle

You can simply use rotation atribute of ImageView

Below is the attribute from ImageView with details from Android source

<!-- rotation of the view, in degrees. -->
<attr name="rotation" format="float" />

How to loop through a HashMap in JSP?

Depending on what you want to accomplish within the loop, iterate over one of these instead:

  • countries.keySet()
  • countries.entrySet()
  • countries.values()

How to run test methods in specific order in JUnit4?

I've read a few answers and agree its not best practice, but the easiest way to order your tests - and the way that JUnit runs tests by default is by alphabetic name ascending.

So just name your tests in the alphabetic order that you want. Also note the test name must begin with the word test. Just watch out for numbers

test12 will run before test2


testA_MyFirstTest testC_ThirdTest testB_ATestThatRunsSecond

Difference between os.getenv and os.environ.get

In Python 2.7 with iPython:

>>> import os
>>> os.getenv??
Signature: os.getenv(key, default=None)
def getenv(key, default=None):
    """Get an environment variable, return None if it doesn't exist.
    The optional second argument can specify an alternate default."""
    return environ.get(key, default)
File:      ~/venv/lib/python2.7/
Type:      function

So we can conclude os.getenv is just a simple wrapper around os.environ.get.

Jupyter Notebook not saving: '_xsrf' argument missing from post

I got the same problem (impossible to save either notebooks and .py modules) using an image in the nvidia docker. The solution was just opening a terminal inside jupyter without typing anything but exit once the files were saved. It was done in the same browser/jupyter instance.

Machine OS: Ubuntu 18.04

How to update a single library with Composer?

To ensure that composer update one package already installed to the last version within the version constraints you've set in composer.json remove the package from vendor and then execute :

php composer.phar update vendor/package

Get a list of resources from classpath directory

Using Reflections

Get everything on the classpath:

Reflections reflections = new Reflections(null, new ResourcesScanner());
Set<String> resourceList = reflections.getResources(x -> true);

Another example - get all files with extension .csv from some.package:

Reflections reflections = new Reflections("some.package", new ResourcesScanner());
Set<String> fileNames = reflections.getResources(Pattern.compile(".*\\.csv"));

Excel: How to check if a cell is empty with VBA?

You could use IsEmpty() function like this:

Set rRng = Sheet1.Range("A10")
If IsEmpty(rRng.Value) Then ...

you could also use following:

If ActiveCell.Value = vbNullString Then ...

Copy Image from Remote Server Over HTTP

Since you've tagged your question 'php', I'll assume your running php on your server. Your best bet is if you control your own web server, then compile cURL into php. This will allow your web server to make requests to other web servers. This can be quite dangerous from a security point of view, so most basic web hosting providers won't have this option enabled.

Here's the php man page on using cURL. In the comments you can find an example which downloads and image file.

If you don't want to use libcurl, you could code something up using fsockopen. This is built into php (but may be disabled on your host), and can directly read and write to sockets. See Examples on the fsockopen man page.

How to make an AJAX call without jQuery?

Try using the Fetch Api (Fetch API)

fetch('').then(response => response.json()).then(data => console.log(data));

Its really clear, and 100% vanilla.

How do I pass multiple attributes into an Angular.js attribute directive?

This worked for me and I think is more HTML5 compliant. You should change your html to use 'data-' prefix

<div data-example-directive data-number="99"></div>

And within the directive read the variable's value:

scope: {
        number : "=",

gpg failed to sign the data fatal: failed to write commit object [Git 2.10.0]

Very much like @birchlabs, after a lot of digging/searching I found that it wasn't GPG, but rather GPG Suite. I did cask reinstall gpg-suite and it solved it for me.

How to make unicode string with python3

the easiest way in python 3.x

text = "hi , I'm text"

socket.error: [Errno 48] Address already in use

Simple solution:

  1. Find the process using port 8080:
`sudo lsof -i:8080`
  1. Kill the process on that port:
`kill $PID`

PID is got from step 1's output.

Why would an Enum implement an Interface?

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

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

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

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

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

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


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

Regex to extract substring, returning 2 results for some reason

I think your problem is that the match method is returning an array. The 0th item in the array is the original string, the 1st thru nth items correspond to the 1st through nth matched parenthesised items. Your "alert()" call is showing the entire array.

symbol(s) not found for architecture i386

Sometimes there are source files which are missing from your target.

  1. examine which symbols are missing
  2. target->build phases->compile source
  3. add the missing source files if they are not listed
  4. command+b for bliss

You can select the files that seem to be "missing" and check in the right-hand utility bar that their checkboxes are selected for the Target you are building.

Retrieve filename from file descriptor in C

As Tyler points out, there's no way to do what you require "directly and reliably", since a given FD may correspond to 0 filenames (in various cases) or > 1 (multiple "hard links" is how the latter situation is generally described). If you do still need the functionality with all the limitations (on speed AND on the possibility of getting 0, 2, ... results rather than 1), here's how you can do it: first, fstat the FD -- this tells you, in the resulting struct stat, what device the file lives on, how many hard links it has, whether it's a special file, etc. This may already answer your question -- e.g. if 0 hard links you will KNOW there is in fact no corresponding filename on disk.

If the stats give you hope, then you have to "walk the tree" of directories on the relevant device until you find all the hard links (or just the first one, if you don't need more than one and any one will do). For that purpose, you use readdir (and opendir &c of course) recursively opening subdirectories until you find in a struct dirent thus received the same inode number you had in the original struct stat (at which time if you want the whole path, rather than just the name, you'll need to walk the chain of directories backwards to reconstruct it).

If this general approach is acceptable, but you need more detailed C code, let us know, it won't be hard to write (though I'd rather not write it if it's useless, i.e. you cannot withstand the inevitably slow performance or the possibility of getting != 1 result for the purposes of your application;-).

What is the difference between JDK and JRE?

If you are a Java programmer you will need JDK in your system and this package will include JRE and JVM as well but if you are normal user who like to play online games then you will only need JRE and this package will not have JDK in it.


JVM (Java Virtual Machine) is an abstract machine. It is a specification that provides runtime environment in which java bytecode can be executed.

JVMs are available for many hardware and software platforms. JVM, JRE and JDK are platform dependent because configuration of each OS differs. But, Java is platform independent.


It contains everything you need to run Java applications in compiled form. You don't need any libraries and other stuffs. All things you need are compiled.

JRE is can not used for development, only used for run the applications.

Java SE Development Kit (JDK)

The JDK includes the JRE plus command-line development tools such as compilers and debuggers that are necessary or useful for developing applets and applications.

(Sources: GeeksForGeeks Q&A, Java Platform Overview)

How to scroll to bottom in react?

I created a empty element in the end of messages, and scrolled to that element. No need of keeping track of refs.

Jquery select change not firing

Try this

$('body').on('change', '#multiid', function() {
    // your stuff

please check .on() selector

JPA OneToMany not deleting child

class Employee {
     private Address address;

See here.

How can I suppress all output from a command using Bash?

The following sends standard output to the null device (bit bucket).

scriptname >/dev/null

And if you also want error messages to be sent there, use one of (the first may not work in all shells):

scriptname &>/dev/null
scriptname >/dev/null 2>&1
scriptname >/dev/null 2>/dev/null

And, if you want to record the messages, but not see them, replace /dev/null with an actual file, such as:

scriptname &>scriptname.out

For completeness, under Windows cmd.exe (where "nul" is the equivalent of "/dev/null"), it is:

scriptname >nul 2>nul

Fit image into ImageView, keep aspect ratio and then resize ImageView to image dimensions?

The Best solution that works in most cases is

Here is an example:

<ImageView android:id="@+id/avatar"

How to convert datatype:object to float64 in python?

You can convert most of the columns by just calling convert_objects:

In [36]:

df = df.convert_objects(convert_numeric=True)
Date         object
WD            int64
Manpower    float64
2nd          object
CTR          object
2ndU        float64
T1            int64
T2          int64
T3           int64
T4        float64
dtype: object

For column '2nd' and 'CTR' we can call the vectorised str methods to replace the thousands separator and remove the '%' sign and then astype to convert:

In [39]:

df['2nd'] = df['2nd'].str.replace(',','').astype(int)
df['CTR'] = df['CTR'].str.replace('%','').astype(np.float64)
Date         object
WD            int64
Manpower    float64
2nd           int32
CTR         float64
2ndU        float64
T1            int64
T2            int64
T3            int64
T4           object
dtype: object
In [40]:

        Date  WD  Manpower   2nd   CTR  2ndU   T1    T2   T3     T4
0   2013/4/6   6       NaN  2645  5.27  0.29  407   533  454    368
1   2013/4/7   7       NaN  2118  5.89  0.31  257   659  583    369
2  2013/4/13   6       NaN  2470  5.38  0.29  354   531  473    383
3  2013/4/14   7       NaN  2033  6.77  0.37  396   748  681    458
4  2013/4/20   6       NaN  2690  5.38  0.29  361   528  541    381

Or you can do the string handling operations above without the call to astype and then call convert_objects to convert everything in one go.


Since version 0.17.0 convert_objects is deprecated and there isn't a top-level function to do this so you need to do:

df.apply(lambda col:pd.to_numeric(col, errors='coerce'))

See the docs and this related question: pandas: to_numeric for multiple columns

Getter and Setter?

I made an experiment using the magic method __call. Not sure if I should post it (because of all the "DO NOT USE MAGIC METHODS" warnings in the other answers and comments) but i'll leave it here.. just in case someone find it useful.

public function __call($_name, $_arguments){
    $action  = substr($_name, 0, 4);
    $varName = substr($_name, 4);

    if (isset($this->{$varName})){
        if ($action === "get_") return $this->{$varName};
        if ($action === "set_") $this->{$varName} = $_arguments[0];

Just add that method above in your class, now you can type:

class MyClass{
    private foo = "bar";
    private bom = "bim";
    // ...
    // public function __call(){ ... }
    // ...
$C = new MyClass();

// as getter
$C->get_foo(); // return "bar"
$C->get_bom(); // return "bim"

// as setter
$C->set_foo("abc"); // set "abc" as new value of foo
$C->set_bom("zam"); // set "zam" as new value of bom

This way you can get/set everything in your class if it exist so, if you need it for only a few specific elements, you could use a "whitelist" as filter.


private $callWhiteList = array(
    "foo" => "foo",
    "fee" => "fee",
    // ...

public function __call($_name, $_arguments){
    $action  = substr($_name, 0, 4);
    $varName = $this->callWhiteList[substr($_name, 4)];

    if (!is_null($varName) && isset($this->{$varName})){
        if ($action === "get_") return $this->{$varName};
        if ($action === "set_") $this->{$varName} = $_arguments[0];

Now you can only get/set "foo" and "fee".
You can also use that "whitelist" to assign custom names to access to your vars.
For example,

private $callWhiteList = array(
    "myfoo" => "foo",
    "zim" => "bom",
    // ...

With that list you can now type:

class MyClass{
    private foo = "bar";
    private bom = "bim";
    // ...
    // private $callWhiteList = array( ... )
    // public function __call(){ ... }
    // ...
$C = new MyClass();

// as getter
$C->get_myfoo(); // return "bar"
$C->get_zim(); // return "bim"

// as setter
$C->set_myfoo("abc"); // set "abc" as new value of foo
$C->set_zim("zam"); // set "zam" as new value of bom

That's all.

Doc: __call() is triggered when invoking inaccessible methods in an object context.

What's the best way to check if a String represents an integer in Java?

If you want to check if the string represents an integer that fits in an int type, I did a little modification to the jonas' answer, so that strings that represent integers bigger than Integer.MAX_VALUE or smaller than Integer.MIN_VALUE, will now return false. For example: "3147483647" will return false because 3147483647 is bigger than 2147483647, and likewise, "-2147483649" will also return false because -2147483649 is smaller than -2147483648.

public static boolean isInt(String s) {
  if(s == null) {
    return false;
  s = s.trim(); //Don't get tricked by whitespaces.
  int len = s.length();
  if(len == 0) {
    return false;
  //The bottom limit of an int is -2147483648 which is 11 chars long.
  //[note that the upper limit (2147483647) is only 10 chars long]
  //Thus any string with more than 11 chars, even if represents a valid integer, 
  //it won't fit in an int.
  if(len > 11) {
    return false;
  char c = s.charAt(0);
  int i = 0;
  //I don't mind the plus sign, so "+13" will return true.
  if(c == '-' || c == '+') {
    //A single "+" or "-" is not a valid integer.
    if(len == 1) {
      return false;
    i = 1;
  //Check if all chars are digits
  for(; i < len; i++) {
    c = s.charAt(i);
    if(c < '0' || c > '9') {
      return false;
  //If we reached this point then we know for sure that the string has at
  //most 11 chars and that they're all digits (the first one might be a '+'
  // or '-' thought).
  //Now we just need to check, for 10 and 11 chars long strings, if the numbers
  //represented by the them don't surpass the limits.
  c = s.charAt(0);
  char l;
  String limit;
  if(len == 10 && c != '-' && c != '+') {
    limit = "2147483647";
    //Now we are going to compare each char of the string with the char in
    //the limit string that has the same index, so if the string is "ABC" and
    //the limit string is "DEF" then we are gonna compare A to D, B to E and so on.
    //c is the current string's char and l is the corresponding limit's char
    //Note that the loop only continues if c == l. Now imagine that our string
    //is "2150000000", 2 == 2 (next), 1 == 1 (next), 5 > 4 as you can see,
    //because 5 > 4 we can guarantee that the string will represent a bigger integer.
    //Similarly, if our string was "2139999999", when we find out that 3 < 4,
    //we can also guarantee that the integer represented will fit in an int.
    for(i = 0; i < len; i++) {
      c = s.charAt(i);
      l = limit.charAt(i);
      if(c > l) {
        return false;
      if(c < l) {
        return true;
  c = s.charAt(0);
  if(len == 11) {
    //If the first char is neither '+' nor '-' then 11 digits represent a 
    //bigger integer than 2147483647 (10 digits).
    if(c != '+' && c != '-') {
      return false;
    limit = (c == '-') ? "-2147483648" : "+2147483647";
    //Here we're applying the same logic that we applied in the previous case
    //ignoring the first char.
    for(i = 1; i < len; i++) {
      c = s.charAt(i);
      l = limit.charAt(i);
      if(c > l) {
        return false;
      if(c < l) {
        return true;
  //The string passed all tests, so it must represent a number that fits
  //in an int...
  return true;

jQuery load more data on scroll

Here is an example:

  1. On scrolling to the bottom, html elements are appeneded. This appending mechanism are only done twice, and then a button with powderblue color is appended at last.

<!DOCTYPE html>_x000D_
    <title>Demo: Lazy Loader</title>_x000D_
    <script src=""></script>_x000D_
        #myScroll {_x000D_
            border: 1px solid #999;_x000D_
        p {_x000D_
            border: 1px solid #ccc;_x000D_
            padding: 50px;_x000D_
            text-align: center;_x000D_
        .loading {_x000D_
            color: red;_x000D_
        .dynamic {_x000D_
  var counter=0;_x000D_
        $(window).scroll(function () {_x000D_
            if ($(window).scrollTop() == $(document).height() - $(window).height() && counter < 2) {_x000D_
        function appendData() {_x000D_
            var html = '';_x000D_
            for (i = 0; i < 10; i++) {_x000D_
                html += '<p class="dynamic">Dynamic Data :  This is test data.<br />Next line.</p>';_x000D_
   $('#myScroll').append('<button id="uniqueButton" style="margin-left: 50%; background-color: powderblue;">Click</button><br /><br />');_x000D_
    <div id="myScroll">_x000D_
            Contents will load here!!!.<br />_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_
        <p >This is test data.<br />Next line.</p>_x000D_

How do I specify "close existing connections" in sql script

try this C# code to drop your database

public static void DropDatabases(string dataBase) {

        string sql =  "ALTER DATABASE "  + dataBase + "SET SINGLE_USER WITH ROLLBACK IMMEDIATE" ;

        using (System.Data.SqlClient.SqlConnection connection = new System.Data.SqlClient.SqlConnection(ConfigurationManager.ConnectionStrings["DBRestore"].ConnectionString))
            using (System.Data.SqlClient.SqlCommand command = new System.Data.SqlClient.SqlCommand(sql, connection))
                command.CommandType = CommandType.Text;
                command.CommandTimeout = 7200;
            sql = "DROP DATABASE " + dataBase;
            using (System.Data.SqlClient.SqlCommand command = new System.Data.SqlClient.SqlCommand(sql, connection))
                command.CommandType = CommandType.Text;
                command.CommandTimeout = 7200;

Find unique lines

I find this easier.

sort -u input_filename > output_filename

-u stands for unique.

Python Pandas: How to read only first n rows of CSV files in?

If you only want to read the first 999,999 (non-header) rows:

read_csv(..., nrows=999999)

If you only want to read rows 1,000,000 ... 1,999,999

read_csv(..., skiprows=1000000, nrows=999999)

nrows : int, default None Number of rows of file to read. Useful for reading pieces of large files*

skiprows : list-like or integer Row numbers to skip (0-indexed) or number of rows to skip (int) at the start of the file

and for large files, you'll probably also want to use chunksize:

chunksize : int, default None Return TextFileReader object for iteration documentation

CSS center content inside div

You just do CSS changes for parent div

.parent-div { 
        text-align: center;
        display: block;

Regex match digits, comma and semicolon?

boolean foundMatch = Pattern.matches("[0-9,;]+", "131;23,87");

HTTP Range header

For folks who are stumbling across Victor Stoddard's answer above in 2019, and become hopeful and doe eyed, note that:

a) Support for X-Content-Duration was removed in Firefox 41:

b) I think it was only supported in Firefox for .ogg audio and .ogv video, not for any other types.

c) I can't see that it was ever supported at all in Chrome, but that may just be a lack of research on my part. But its presence or absence seems to have no effect one way or another for webm or ogv videos as of today in Chrome 71.

d) I can't find anywhere where 'Content-Duration' replaced 'X-Content-Duration' for anything, I don't think 'X-Content-Duration' lived long enough for there to be a successor header name.

I think this means that, as of today if you want to serve webm or ogv containers that contain streams that don't know their duration (e.g. the output of an ffpeg pipe) to Chrome or FF, and you want them to be scrubbable in an HTML 5 video element, you are probably out of luck. Firefox 64.0 makes a half hearted attempt to make these scrubbable whether or not you serve via range requests, but it gets confused and throws up a spinning wheel until the stream is completely downloaded if you seek a few times more than it thinks is appropriate. Chrome doesn't even try, it just nopes out and won't let you scrub at all until the entire stream is finished playing.

append multiple values for one key in a dictionary

d = {} 

# import list of year,value pairs

for year,value in mylist:
    except KeyError:
        d[year] = [value]

The Python way - it is easier to receive forgiveness than ask permission!

A table name as a variable

You can't use a table name for a variable. You'd have to do this instead:

DECLARE @sqlCommand varchar(1000)
SET @sqlCommand = 'SELECT * from yourtable'
EXEC (@sqlCommand)

Get all unique values in a JavaScript array (remove duplicates)

The Object answer above does not seem to work for me in my use case with Objects.

I have modified it as follows:

var j = {};

this.forEach( function(v) {
   var typ = typeof v;
   var v = (typ === 'object') ? JSON.stringify(v) : v;

   j[v + '::' + typ] = v;

return Object.keys(j).map(function(v){
  if ( v.indexOf('::object') > -1 ) {
    return JSON.parse(j[v]);

  return j[v];

This seems to now work correctly for objects, arrays, arrays with mixed values, booleans, etc.

AWS CLI S3 A client error (403) occurred when calling the HeadObject operation: Forbidden

I've had this issue, adding --recursive to the command will help.

At this point it doesn't quite make sense as you (like me) are only trying to copy a single file down, but it does the trick!

How can I get the source code of a Python function?

You can use inspect module to get full source code for that. You have to use getsource() method for that from the inspect module. For example:

import inspect

def get_my_code():
    x = "abcd"
    return x


You can check it out more options on the below link. retrieve your python code

Get current URL from IFRAME

I had an issue with blob url hrefs. So, with a reference to the iframe, I just produced an url from the iframe's src attribute:

    const iframeReference = document.getElementById("iframe_id");
    const iframeUrl = iframeReference ? new URL(iframeReference.src) : undefined;
    if (iframeUrl) {
        console.log("Voila: " + iframeUrl);
    } else {
        console.warn("iframe with id iframe_id not found");

Fatal error: Call to undefined function mysql_connect() in C:\Apache\htdocs\test.php on line 2

Change the database.php file from

$db['default']['dbdriver'] = 'mysql';


$db['default']['dbdriver'] = 'mysqli';

Fatal error: Call to a member function bind_param() on boolean

You should always try as much as possible to always put your statements in a try catch block ... it will always help in situations like this and will let you know whats wrong. Perhaps the table name or column name is wrong.

Difference between HashMap and Map in Java..?

Map<K,V> is an interface, HashMap<K,V> is a class that implements Map.

you can do

Map<Key,Value> map = new HashMap<Key,Value>();

Here you have a link to the documentation of each one: Map, HashMap.

Accessing a resource via codebehind in WPF

Not exactly direct answer, but strongly related:

In case the resources are in a different file - for example ResourceDictionary.xaml

You can simply add x:Class to it:

<ResourceDictionary x:Class="Namespace.NewClassName"
                    xmlns:x="" >
    <ds:MyCollection x:Key="myKey" x:Name="myName" />

And then use it in code behind:

var res = new Namespace.NewClassName();
var col = res["myKey"];

How to validate phone number in laravel 5.2?

You can try out this phone validator package. Laravel Phone


I recently discovered another package Lavarel Phone Validator (stuyam/laravel-phone-validator), that uses the free Twilio phone lookup service

How to solve this java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream?

just put all apache comons jar and file upload jar in lib folder of tomcat

Using 24 hour time in bootstrap timepicker

"YYYY-MM-DD HH:mm:ss" => 24 hours format;

"YYYY-MM-DD hh:mm:ss" => 12 hours format;

the difference is letter 'H'

PHP mPDF save file as PDF

The mPDF docs state that the first argument of Output() is the file path, second is the saving mode - you need to set it to 'F'.


Fast and Lean PDF Viewer for iPhone / iPad / iOS - tips and hints?

I have build such kind of application using approximatively the same approach except :

  • I cache the generated image on the disk and always generate two to three images in advance in a separate thread.
  • I don't overlay with a UIImage but instead draw the image in the layer when zooming is 1. Those tiles will be released automatically when memory warnings are issued.

Whenever the user start zooming, I acquire the CGPDFPage and render it using the appropriate CTM. The code in - (void)drawLayer: (CALayer*)layer inContext: (CGContextRef) context is like :

CGAffineTransform currentCTM = CGContextGetCTM(context);    
if (currentCTM.a == 1.0 && baseImage) {
    //Calculate ideal scale
    CGFloat scaleForWidth = baseImage.size.width/self.bounds.size.width;
    CGFloat scaleForHeight = baseImage.size.height/self.bounds.size.height; 
    CGFloat imageScaleFactor = MAX(scaleForWidth, scaleForHeight);

    CGSize imageSize = CGSizeMake(baseImage.size.width/imageScaleFactor, baseImage.size.height/imageScaleFactor);
    CGRect imageRect = CGRectMake((self.bounds.size.width-imageSize.width)/2, (self.bounds.size.height-imageSize.height)/2, imageSize.width, imageSize.height);
    CGContextDrawImage(context, imageRect, [baseImage CGImage]);
} else {
    @synchronized(issue) { 
        CGPDFPageRef pdfPage = CGPDFDocumentGetPage(issue.pdfDoc, pageIndex+1);
        pdfToPageTransform = CGPDFPageGetDrawingTransform(pdfPage, kCGPDFMediaBox, layer.bounds, 0, true);
        CGContextConcatCTM(context, pdfToPageTransform);    
        CGContextDrawPDFPage(context, pdfPage);

issue is the object containg the CGPDFDocumentRef. I synchronize the part where I access the pdfDoc property because I release it and recreate it when receiving memoryWarnings. It seems that the CGPDFDocumentRef object do some internal caching that I did not find how to get rid of.

Multiple IF AND statements excel

Consider that you have multiple "tests", e.g.,

  1. If E2 = 'in play' and F2 = 'closed', output 3
  2. If E2 = 'in play' and F2 = 'suspended', output 2
  3. Etc.

What you really need to do is put successive tests in the False argument. You're presently trying to separate each test by a comma, and that won't work.

Your first three tests can all be joined in one expression like:

=IF(E2="In Play",IF(F2="Closed",3,IF(F2="suspended",2,IF(F2="Null",1))))

Remembering that each successive test needs to be the nested FALSE argument of the preceding test, you can do this:

=IF(E2="In Play",IF(F2="Closed",3,IF(F2="suspended",2,IF(F2="Null",1))),IF(AND(E2="Pre-Play",F2="Null"),-1,IF(AND(E2="completed",F2="closed"),2,IF(AND(E2="suspended",F2="Null"),3,-2))))

How to add a border just on the top side of a UIView

Personally I like the sub-classing of the view + drawRect, but here's just another way of going about it (and it kind of works along the same lines as the accepted answer by @If Pollavith):

Your new border layer can be set up to have whatever dimensions you like. So, like @If Pollavith's answer, you create a layer to be as tall as you want it to be, and as wide as the view you want to have bordered. Use the layer's frame definition to place it where you want it, and then add it as a sub-layer to your view.

For reference, my own requirement was to put a border on the LEFT-HAND side of the view (please don't cut and paste this code and dis' me just 'cos it doesn't put a border at the top of the view -- modifying the code below is simple enough):

    CALayer *leftBorder = [CALayer layer];
leftBorder.borderColor = [UIColor colorWithRed:0.0 green:91.0/255.0 blue:141.0/255.0 alpha:1.0].CGColor;
leftBorder.borderWidth = 1;
leftBorder.frame = CGRectMake(0, 0, 1.0, CGRectGetHeight(self.myTargetView.frame));
[self.myTargetView.layer addSublayer:leftBorder];

I guess the only moderate benefit over this and making a small UIView or UILabel is that the CALayer is supposedly 'lighter-weight', and there's a lot of interesting views (as in opinions) about over-riding drawRect versus using CALayers (like here: iOS: Using UIView's 'drawRect:' vs. its layer's delagate 'drawLayer:inContext:').


I like the colour blue.

How to add new DataRow into DataTable?

This works for me:

var table = new DataTable();

Return array from function

Your BlockID function uses the undefined variable images, which will lead to an error. Also, you should not use an Array here - JavaScripts key-value-maps are plain objects:

function BlockID() {
    return {
        "s": "Images/Block_01.png",
        "g": "Images/Block_02.png",
        "C": "Images/Block_03.png",
        "d": "Images/Block_04.png"

Get height of div with no height set in css

Also make sure the div is currently appended to the DOM and visible.

$(document).on('click', '#id', function() {}) vs $('#id').on('click', function(){})

Consider following code

<ul id="myTask">
  <li>Getting Paid</li>

Now, here goes the difference

// Remove the myTask item when clicked.
$('#myTask').children().click(function () {

Now, what if we add a myTask again?

$('#myTask').append('<li>Answer this question on SO</li>');

Clicking this myTask item will not remove it from the list, since it doesn't have any event handlers bound. If instead we'd used .on, the new item would work without any extra effort on our part. Here's how the .on version would look:

$('#myTask').on('click', 'li', function (event) {


The difference between .on() and .click() would be that .click() may not work when the DOM elements associated with the .click() event are added dynamically at a later point while .on() can be used in situations where the DOM elements associated with the .on() call may be generated dynamically at a later point.

How to handle the modal closing event in Twitter Bootstrap?

If your modal div is dynamically added then use( For bootstrap 3 and 4)

$(document).on('','#modal-id', function () {
 //Do stuff here

This will work for non-dynamic content also.

Storing a Key Value Array into a compact JSON string

To me, this is the most "natural" way to structure such data in JSON, provided that all of the keys are strings.

    "keyvaluelist": {
        "slide0001.html": "Looking Ahead",
        "slide0008.html": "Forecast",
        "slide0021.html": "Summary"
    "otherdata": {
        "one": "1",
        "two": "2",
        "three": "3"
    "anotherthing": "thing1",
    "onelastthing": "thing2"

I read this as

a JSON object with four elements
    element 1 is a map of key/value pairs named "keyvaluelist",
    element 2 is a map of key/value pairs named "otherdata",
    element 3 is a string named "anotherthing",
    element 4 is a string named "onelastthing"

The first element or second element could alternatively be described as objects themselves, of course, with three elements each.

Removing items from a ListBox in

I think your ListBox already clear with ListBox2.Items.Clear(). The problem is that you also need to clear your dataset from previous results with ds6.Tables.Clear().

Add this in your code:

da6 = New SqlDataAdapter("select distinct(component_type) from component where   component_name='" & ListBox1.SelectedItem() & "'", con)
    ListBox1.Items.Clear()    ' clears ListBox1
    ListBox2.Items.Clear()    ' clears ListBox2
    ds6.Tables.Clear()        ' clears DataSet  <======= DON'T FORGET TO DO THIS
da6.Fill(ds6, "component")
For Each row As DataRow In ds6.Tables(0).Rows
    ListBox2.Items.Add(row.Field(Of String)("component_type"))

Function of Project > Clean in Eclipse

It removes whatever already-compiled files are in your project so that you can do a complete fresh rebuild.

Jquery/Ajax Form Submission (enctype="multipart/form-data" ). Why does 'contentType:False' cause undefined index in PHP?

contentType option to false is used for multipart/form-data forms that pass files.

When one sets the contentType option to false, it forces jQuery not to add a Content-Type header, otherwise, the boundary string will be missing from it. Also, when submitting files via multipart/form-data, one must leave the processData flag set to false, otherwise, jQuery will try to convert your FormData into a string, which will fail.

To try and fix your issue:

Use jQuery's .serialize() method which creates a text string in standard URL-encoded notation.

You need to pass un-encoded data when using contentType: false.

Try using new FormData instead of .serialize():

  var formData = new FormData($(this)[0]);

See for yourself the difference of how your formData is passed to your php page by using console.log().

  var formData = new FormData($(this)[0]);

  var formDataSerialized = $(this).serialize();

How to get full file path from file name?

You Can use:

string path = Path.GetFullPath(FileName);

it will return the Full path of that mentioned file.

installing JDK8 on Windows XP - advapi32.dll error

This happens because Oracle dropped support for Windows XP (which doesn't have RegDeleteKeyExA used by the installer in its ADVAPI32.DLL by the way) as described in Yet while the official support for XP has ended, the Java binaries are still (as of Java 8u20 EA b05 at least) XP-compatible - only the installer isn't...

Because of that, the solution is actually quite easy:

  1. get 7-Zip (or any other good unpacker), unpack the distribution .exe manually, it has one .zip file inside of it (, extract it too,

  2. use unpack200 from JDK8 to unpack all .pack files to .jar files (older unpacks won't work properly); JAVA_HOME environment variable should be set to your Java unpack root, e.g. "C:\Program Files\Java\jdk8" - you can specify it implicitly by e.g.

    SET JAVA_HOME=C:\Program Files\Java\jdk8
    • Unpack all files with a single command (in batch file):

      FOR /R %%f IN (*.pack) DO "%JAVA_HOME%\bin\unpack200.exe" -r -v "%%f" "%%~pf%%~nf.jar"
    • Unpack all files with a single command (command line from JRE root):

      FOR /R %f IN (*.pack) DO "bin\unpack200.exe" -r -v "%f" "%~pf%~nf.jar"
    • Unpack by manually locating the files and unpacking them one-by-one:

      %JAVA_HOME%\bin\unpack200 -r packname.pack packname.jar

    where packname is for example rt

  3. point the tool you want to use (e.g. Netbeans) to the %JAVA_HOME% and you're good to go.

Note: you probably shouldn't do this just to use Java 8 in your web browser or for any similar reason (installing JRE 8 comes to mind); security flaws in early updates of major Java version releases are (mind me) legendary, and adding to that no real support for neither XP nor Java 8 on XP only makes matters much worse. Not to mention you usually don't need Java in your browser (see e.g. - the topic is already covered on many pages, just Google it if you require further info). In any case, AFAIK the only thing required to apply this procedure to JRE is to change some of the paths specified above from \bin\ to \lib\ (the file placement in installer directory tree is a bit different) - yet I strongly advise against doing it.

See also: How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?, JRE 1.7 - java version - returns: java/lang/NoClassDefFoundError: java/lang/Object

Unresolved external symbol on static class members

Static data members declarations in the class declaration are not definition of them. To define them you should do this in the .CPP file to avoid duplicated symbols.

The only data you can declare and define is integral static constants. (Values of enums can be used as constant values as well)

You might want to rewrite your code as:

class test {
  const static unsigned char X = 1;
  const static unsigned char Y = 2;

test::test() {

If you want to have ability to modify you static variables (in other words when it is inappropriate to declare them as const), you can separate you code between .H and .CPP in the following way:

.H :

class test {

  static unsigned char X;
  static unsigned char Y;



.CPP :

unsigned char test::X = 1;
unsigned char test::Y = 2;

  // constructor is empty.
  // We don't initialize static data member here, 
  // because static data initialization will happen on every constructor call.

Proper MIME media type for PDF files

From Wikipedia Media type,

A media type is composed of a type, a subtype, and optional parameters. As an example, an HTML file might be designated text/html; charset=UTF-8.

Media type consists of top-level type name and sub-type name, which is further structured into so-called "trees".

top-level type name / subtype name [ ; parameters ]

top-level type name / [ tree. ] subtype name [ +suffix ] [ ; parameters ]

All media types should be registered using the IANA registration procedures. Currently the following trees are created: standard, vendor, personal or vanity, unregistered x.


Media types in the standards tree do not use any tree facet (prefix).

type / media type name [+suffix]

Examples: "application/xhtml+xml", "image/png"


Vendor tree is used for media types associated with publicly available products. It uses vnd. facet.

type / vnd. media type name [+suffix] - used in the case of well-known producer

type / vnd. producer's name followed by media type name [+suffix] - producer's name must be approved by IANA

type / vnd. producer's name followed by product's name [+suffix] - producer's name must be approved by IANA

Personal or Vanity tree:

Personal or Vanity tree includes media types created experimentally or as part of products that are not distributed commercially. It uses prs. facet.

type / prs. media type name [+suffix]

Unregistered x. tree:

The "x." tree may be used for media types intended exclusively for use in private, local environments and only with the active agreement of the parties exchanging them. Types in this tree cannot be registered.

According to the previous version of RFC 6838 - obsoleted RFC 2048 (published in November 1996) it should rarely, if ever, be necessary to use unregistered experimental types, and as such use of both "x-" and "x." forms is discouraged. Previous versions of that RFC - RFC 1590 and RFC 1521 stated that the use of "x-" notation for the sub-type name may be used for unregistered and private sub-types, but this recommendation was obsoleted in November 1996.

type / x. media type name [+suffix]

So its clear that the standard type MIME type application/pdf is the appropriate one to use while you should avoid using the obsolete and unregistered x- media type as stated in RFC 2048 and RFC 6838.

How to send email from localhost WAMP Server to send email Gmail Hotmail or so forth?

Configuring a working email client from localhost is quite a chore, I have spent hours of frustration attempting it. At last I have found this way to send mails (using WAMP, XAMPP, etc.):

Install hMailServer

Configure this hMailServer setting:

  1. Open hMailServer Administrator.
  2. Click the "Add domain ..." button to create a new domain.
  3. Under the domain text field, enter your computer's localhost IP.
    • Example: is your localhost IP.
  4. Click the "Save" button.
  5. Now go to Settings > Protocols > SMTP and select the "Delivery of Email" tab.
  6. Find the localhost field enter "localhost".
  7. Click the Save button.

Configure your Gmail account, perform following modification:

  1. Go to Settings > Protocols > SMTP and select "Delivery of Email" tab.
  2. Enter "" in the Remote Host name field.
  3. Enter "465" as the port number.
  4. Check "Server requires authentication".
  5. Enter your Google Mail address in the Username field.
  6. Enter your Google Mail password in the password field.
  7. Check mark "Use SSL"
  8. Save all changes.


If you want to send email from another computer you need to allow deliveries from External to External accounts by following steps:

  1. Go to Settings > Advanced > IP Ranges and double click on "My Computer" which should have IP address of
  2. Check the Allow Deliveries from External to External accounts Checkbox.
  3. Save settings using Save button.

How to do a case sensitive search in WHERE clause (I'm using SQL Server)?

select * from incidentsnew1 

Simplest code for array intersection in javascript

function intersectionOfArrays(arr1, arr2) {
    return arr1.filter((element) => arr2.indexOf(element) !== -1).filter((element, pos, self) => self.indexOf(element) == pos);

How do I get specific properties with Get-AdUser

This worked for me as well:

Get-ADUser -Filter * -SearchBase "ou=OU,dc=Domain,dc=com" -Properties Enabled, CanonicalName, Displayname, Givenname, Surname, EmployeeNumber, EmailAddress, Department, StreetAddress, Title | select Enabled, CanonicalName, Displayname, GivenName, Surname, EmployeeNumber, EmailAddress, Department, Title | Export-CSV "C:\output.csv"

Multiple HttpPost method in Web API controller

I think the question has already been answered. I was also looking for something a webApi controller that has same signatured mehtods but different names. I was trying to implement the Calculator as WebApi. Calculator has 4 methods with the same signature but different names.

public class CalculatorController : ApiController
    public string Add(int num1 = 1, int num2 = 1, int timeDelay = 1)
        Thread.Sleep(1000 * timeDelay);
        return string.Format("Add = {0}", num1 + num2);

    public string Sub(int num1 = 1, int num2 = 1, int timeDelay = 1)
        Thread.Sleep(1000 * timeDelay);
        return string.Format("Subtract result = {0}", num1 - num2);

    public string Mul(int num1 = 1, int num2 = 1, int timeDelay = 1)
        Thread.Sleep(1000 * timeDelay);
        return string.Format("Multiplication result = {0}", num1 * num2);

    public string Div(int num1 = 1, int num2 = 1, int timeDelay = 1)
        Thread.Sleep(1000 * timeDelay);
        return string.Format("Division result = {0}", num1 / num2);

and in the WebApiConfig file you already have

            name: "DefaultApi",
            routeTemplate: "api/{controller}/{action}/{id}",
            defaults: new { id = RouteParameter.Optional });

Just set the authentication / authorisation on IIS and you are done!

Hope this helps!

Accessing dict_keys element by index in Python3

In many cases, this may be an XY Problem. Why are you indexing your dictionary keys by position? Do you really need to? Until recently, dictionaries were not even ordered in Python, so accessing the first element was arbitrary.

I just translated some Python 2 code to Python 3:

keys = d.keys()
for (i, res) in enumerate(some_list):
    k = keys[i]
    # ...

which is not pretty, but not very bad either. At first, I was about to replace it by the monstrous

    k = next(itertools.islice(iter(keys), i, None))

before I realised this is all much better written as

for (k, res) in zip(d.keys(), some_list):

which works just fine.

I believe that in many other cases, indexing dictionary keys by position can be avoided. Although dictionaries are ordered in Python 3.7, relying on that is not pretty. The code above only works because the contents of some_list had been recently produced from the contents of d.

Have a hard look at your code if you really need to access a disk_keys element by index. Perhaps you don't need to.

C: Run a System Command and Get Output?

You need some sort of Inter Process Communication. Use a pipe or a shared buffer.

Maximum number of rows in an MS Access database engine table?

We're not necessarily talking theoretical limits here, we're talking about real world limits of the 2GB max file size AND database schema.

  • Is your db a single table or multiple?
  • How many columns does each table have?
  • What are the datatypes?

The schema is on even footing with the row count in determining how many rows you can have.

We have used Access MDBs to store exports of MS-SQL data for statistical analysis by some of our corporate users. In those cases we've exported our core table structure, typically four tables with 20 to 150 columns varying from a hundred bytes per row to upwards of 8000 bytes per row. In these cases, we would bump up against a few hundred thousand rows of data were permissible PER MDB that we would ship them.

So, I just don't think that this question has an answer in absence of your schema.

How to handle iframe in Selenium WebDriver using java

Selenium Web Driver Handling Frames
It is impossible to click iframe directly through XPath since it is an iframe. First we have to switch to the frame and then we can click using xpath.

driver.switchTo().frame() has multiple overloads.

  1. driver.switchTo().frame(name_or_id)
    Here your iframe doesn't have id or name, so not for you.

  2. driver.switchTo().frame(index)
    This is the last option to choose, because using index is not stable enough as you could imagine. If this is your only iframe in the page, try driver.switchTo().frame(0)

  3. driver.switchTo().frame(iframe_element)
    The most common one. You locate your iframe like other elements, then pass it into the method.

driver.switchTo().defaultContent(); [parentFrame, defaultContent, frame]

// Based on index position:
int frameIndex = 0;
List<WebElement> listFrames = driver.findElements(By.tagName("iframe"));
System.out.println("list frames   "+listFrames.size());
driver.switchTo().frame(listFrames.get( frameIndex ));

// XPath|CssPath Element:
WebElement frameCSSPath = driver.findElement(By.cssSelector("iframe[title='Fill Quote']"));
WebElement frameXPath = driver.findElement(By.xpath(".//iframe[1]"));
WebElement frameTag = driver.findElement(By.tagName("iframe"));

driver.switchTo().frame( frameCSSPath ); // frameXPath, frameTag

driver.switchTo().frame("relative=up"); // focus to parent frame.
driver.switchTo().defaultContent(); // move to the most parent or main frame

// For alert's
Alert alert = driver.switchTo().alert(); // Switch to alert pop-up

XML Test:

    <IFame id='1'>...       parentFrame() « context remains unchanged. <IFame1>
     -> <IFrame id='2'>...  parentFrame() « Change focus to the parent context. <IFame1>

<frameset cols="50%,50%">
    <Fame id='11'>...     defaultContent() « driver focus to top window/first frame. <html>
     -> <Frame id='22'>... defaultContent() « driver focus to top window/first frame. <Fame11> 
                           frame("relative=up") « focus to parent frame. <Fame11>

Conversion of RC to Web-Driver Java commands. link.

<frame> is an HTML element which defines a particular area in which another HTML document can be displayed. A frame should be used within a <frameset>. « Deprecated. Not for use in new websites.

IN vs OR in the SQL WHERE Clause

The best way to find out is looking at the Execution Plan.

I tried it with Oracle, and it was exactly the same.

CREATE TABLE performance_test AS ( SELECT * FROM dba_objects );

SELECT * FROM performance_test

Even though the query uses IN, the Execution Plan says that it uses OR:

| Id  | Operation         | Name             | Rows  | Bytes | Cost (%CPU)| Time     |    
|   0 | SELECT STATEMENT  |                  |     8 |  1416 |   163   (2)| 00:00:02 |    
|*  1 |  TABLE ACCESS FULL| PERFORMANCE_TEST |     8 |  1416 |   163   (2)| 00:00:02 |    

Predicate Information (identified by operation id):                                       

   1 - filter("OBJECT_NAME"='DBMS_LOB' OR "OBJECT_NAME"='DBMS_REGISTRY' OR                

The 'Access-Control-Allow-Origin' header contains multiple values

This happens when you have Cors option configured at multiple locations. In my case I had it at the controller level as well as in the Startup.Auth.cs/ConfigureAuth.

My understanding is if you want it application wide then just configure it under Startup.Auth.cs/ConfigureAuth like this...You will need reference to Microsoft.Owin.Cors

public void ConfigureAuth(IAppBuilder app)

If you rather keep it at the controller level then you may just insert at the Controller level.

[EnableCors("http://localhost:24589", "*", "*")]
    public class ProductsController : ApiController
        ProductRepository _prodRepo;

Laravel 5 call a model function in a blade view

I solve the problem. So simple. Syntax error.

  • App\Product
  • App\Service

enter image description here

But I also want to know how to pass a function with parameters to view....

Delete all items from a c++ std::vector

If your vector look like this std::vector<MyClass*> vecType_pt you have to explicitly release memory ,Or if your vector look like : std::vector<MyClass> vecType_obj , constructor will be called by vector.Please execute example given below , and understand the difference :

  class MyClass
    int main() 
        typedef std::vector<MyClass*> vecType_ptr;
        typedef std::vector<MyClass> vecType_obj;
        vecType_ptr myVec_ptr;
        vecType_obj myVec_obj;
        MyClass obj;
        for(int i=0;i<5;i++)
            MyClass *ptr=new MyClass();
        cout<<"\n\n---------------------If pointer stored---------------------"<<endl;
        myVec_ptr.erase (myVec_ptr.begin(),myVec_ptr.end());
        cout<<"\n\n---------------------If object stored---------------------"<<endl;
        myVec_obj.erase (myVec_obj.begin(),myVec_obj.end());
        return 0;

How can I enter latitude and longitude in Google Maps?

You don't need to convert to decimal; you can also enter 46 23S, 115 22E. You can add seconds after the minutes, also separated by a space.

How to make html <select> element look like "disabled", but pass values?

if you don't want add the attr disabled can do it programmatically

can disable the edition into the <select class="yourClass"> element with this code:

//bloqueo selects
  //block all selects
  jQuery(document).on("focusin", 'select.yourClass', function (event) {
    var $selectDiabled = jQuery(this).attr('disabled', 'disabled');
    setTimeout(function(){ $selectDiabled.removeAttr("disabled"); }, 30);

if you want try it can see it here:

java.lang.NoClassDefFoundError: org/json/JSONObject

No.. It is not proper way. Refer the steps,

For Classpath reference: Right click on project in Eclipse -> Buildpath -> Configure Build path -> Java Build Path (left Pane) -> Libraries(Tab) -> Add External Jars -> Select your jar and select OK.

For Deployment Assembly: Right click on WAR in eclipse-> Buildpath -> Configure Build path -> Deployment Assembly (left Pane) -> Add -> External file system -> Add -> Select your jar -> Add -> Finish.

This is the proper way! Don't forget to remove environment variable. It is not required now.

Try this. Surely it will work. Try to use Maven, it will simplify you task.

Http Post With Body

You can use HttpClient and HttpPost to send a json string as body:

public void post(String completeUrl, String body) {
    HttpClient httpClient = new DefaultHttpClient();
    HttpPost httpPost = new HttpPost(completeUrl);
    httpPost.setHeader("Content-type", "application/json");
    try {
        StringEntity stringEntity = new StringEntity(body);

    } catch (Exception e) {
        throw new RuntimeException(e);

Json body example:

  "param1": "value 1",
  "param2": 123,
  "testStudentArray": [
      "name": "Test Name 1",
      "gpa": 3.5
      "name": "Test Name 2",
      "gpa": 3.8

"Continue" (to next iteration) on VBScript

A solution I decided on involved the use of a boolean variable to track if the for loop should process its instructions or skip to the next iteration:

Dim continue

For Each item In collection
    continue = True

    If condition1 Then continue = False End If

    If continue Then
        'Do work
    End If

I found the nested loop solutions to be somewhat confusing readability wise. This method also has its own pitfalls since the loop doesn't immediately skip to the next iteration after encountering continue. It would be possible for a later condition to reverse the state of continue. It also has a secondary construct within the initial loop, and requires the declaration of an extra var.

Oh, VBScript...sigh.

Also, if you want to use the accepted answer, which isn't too bad readability wise, you could couple that with the use of : to merge the two loops into what appears to be one:

Dim i

For i = 0 To 10 : Do
    If i = 4 Then Exit Do
    WScript.Echo i
Loop While False : Next

I found it useful to eliminate the extra level of indentation.

How to open a second activity on click of button in android app

Button btn = (Button) findViewById(;

btn.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        Intent myIntent = new Intent(MainActivity.this, MainActivity2.class);

The answer for the complete noob from a complete noob: MainActivity is the name of the first activity. MainActivity2 is the name of the second activity. button1 is the I.D of the button in xml for MainActivity Activity.

Call Javascript onchange event by programmatically changing textbox value

You're population is from the server-side. Using the registerclientscript will put the script at the beginning of the form.. you'll want to use RegisterStartupScript(Block) to have the script placed at the end of the page in question.

The former tries to run the script before the text area exists in the dom, the latter will run the script after that element in the page is created.

get all characters to right of last dash

You could use LINQ, and save yourself the explicit parsing:

string test = "9586-202-10072";
string lastFragment = test.Split('-').Last();


How do I use Access-Control-Allow-Origin? Does it just go in between the html head tags?

<?php header("Access-Control-Allow-Origin:"); ?>

This command disables only first console warning info


Result: console result

How to change the sender's name or e-mail address in mutt?

If you just want to change it once, you can specify the 'from' header in command line, eg:

mutt -e 'my_hdr From:[email protected]'

my_hdr is mutt's command of providing custom header value.

One last word, don't be evil!

The performance impact of using instanceof in Java

Demian and Paul mention a good point; however, the placement of the code to execute really depends on how you want to use the data...

I'm a big fan of small data objects that can be used in many ways. If you follow the override (polymorphic) approach, your objects can only be used "one way".

This is where patterns come in...

You can use double-dispatch (as in the visitor pattern) to ask each object to "call you" passing itself -- this will resolve the type of the object. However (again) you'll need a class that can "do stuff" with all of the possible subtypes.

I prefer to use a strategy pattern, where you can register strategies for each subtype you want to handle. Something like the following. Note that this only helps for exact type matches, but has the advantage that it's extensible - third-party contributors can add their own types and handlers. (This is good for dynamic frameworks like OSGi, where new bundles can be added)

Hopefully this will inspire some other ideas...

package com.javadude.sample;

import java.util.HashMap;
import java.util.Map;

public class StrategyExample {
    static class SomeCommonSuperType {}
    static class SubType1 extends SomeCommonSuperType {}
    static class SubType2 extends SomeCommonSuperType {}
    static class SubType3 extends SomeCommonSuperType {}

    static interface Handler<T extends SomeCommonSuperType> {
        Object handle(T object);

    static class HandlerMap {
        private Map<Class<? extends SomeCommonSuperType>, Handler<? extends SomeCommonSuperType>> handlers_ =
            new HashMap<Class<? extends SomeCommonSuperType>, Handler<? extends SomeCommonSuperType>>();
        public <T extends SomeCommonSuperType> void add(Class<T> c, Handler<T> handler) {
            handlers_.put(c, handler);
        public <T extends SomeCommonSuperType> Object handle(T o) {
            return ((Handler<T>) handlers_.get(o.getClass())).handle(o);

    public static void main(String[] args) {
        HandlerMap handlerMap = new HandlerMap();

        handlerMap.add(SubType1.class, new Handler<SubType1>() {
            @Override public Object handle(SubType1 object) {
                System.out.println("Handling SubType1");
                return null;
            } });
        handlerMap.add(SubType2.class, new Handler<SubType2>() {
            @Override public Object handle(SubType2 object) {
                System.out.println("Handling SubType2");
                return null;
            } });
        handlerMap.add(SubType3.class, new Handler<SubType3>() {
            @Override public Object handle(SubType3 object) {
                System.out.println("Handling SubType3");
                return null;
            } });

        SubType1 subType1 = new SubType1();
        SubType2 subType2 = new SubType2();
        SubType3 subType3 = new SubType3();

javascript how to create a validation error message without using alert

You need to stop the submission if an error occured:


<form name ="myform" onsubmit="return validation();"> 


if (document.myform.username.value == "") {
     document.getElementById('errors').innerHTML="*Please enter a username*";
     return false;

SeekBar and media player in android

Based on previous statements, for better performance, you can also add an if condition

if (player.isPlaying() {
    handler.postDelayed(..., 1000);

List all of the possible goals in Maven 2?

If you use IntelliJ IDEA you can browse all maven goals/tasks (including plugins) in Maven Projects tab:

Maven Projects

Updating user data - ASP.NET Identity

I am using .Net Core 3.1 or higher version.Please follow the solution:

  public class UpdateAssignUserRole
        public string username { get; set; }
        public string rolename { get; set; }
        public bool IsEdit { get; set; }


 private async Task UpdateSeedUsers(UserManager<IdentityUser> userManager, UpdateAssignUserRole updateassignUsername)
            IList<Users> Users = await FindByUserName(updateassignUsername.username);

            if (await userManager.FindByNameAsync(updateassignUsername.username) != null)
                var user = new IdentityUser
                    UserName = updateassignUsername.username,
                    Email = Users[0].Email,
                var result = await userManager.FindByNameAsync(updateassignUsername.username);
                if (result != null)
                    IdentityResult deletionResult = await userManager.RemoveFromRolesAsync(result, await userManager.GetRolesAsync(result));
                    if (deletionResult != null)
                        await userManager.AddToRoleAsync(result, updateassignUsername.rolename);


Number format in excel: Showing % value without multiplying with 100

_ [$%-4009] * #,##0_ ;_ [$%-4009] * -#,##0_ ;_ [$%-4009] * "-"??_ ;_ @_ 

How to change Oracle default data pump directory to import dumpfile?

You can use the following command to update the DATA PUMP DIRECTORY path,

create or replace directory DATA_PUMP_DIR as '/u01/app/oracle/admin/MYDB/dpdump/';

For me data path correction was required as I have restored the my database from production to test environment.

Same command can be used to create a new DATA PUMP DIRECTORY name and path.

ActiveMQ or RabbitMQ or ZeroMQ or

I wrote about my initial experience regarding AMQP, Qpid and ZeroMQ here:

My subjective opinion is that AMQP is fine if you really need the persistent messaging facilities and is not too concerned that the broker may be a bottleneck. Also, C++ client is currently missing for AMQP (Qpid didn't win my support; not sure about the ActiveMQ client however), but maybe work in progress. ZeroMQ may be the way otherwise.

Keyboard shortcut to change font size in Eclipse?

Take a look at this project:

It has some other features, but most importantly, it has Ctrl++ and Ctrl+- to change the font size, it's awesome.

json_decode returns NULL after webservice call

I was having this problem, when I was calling a soap method to obtain my data, and then return a json string, when I tried to do json_decode I just keep getting null.

Since I was using nusoap to do the soap call I tried to just return json string and now I could do a json_decode, since I really neaded to get my data with a SOAP call, what I did was add ob_start() before include nusoap, id did my call genereate json string, and then before returning my json string I did ob_end_clean(), and GOT MY PROBLEM FIXED :)


//verifica se um num assoc deco é valido
$aResponse['SimpleIsMemberResult']['IsMember'] = FALSE;
        $client = new soapclientNusoap(PartnerService.svc?wsdl',
            // OPTS 
            'trace' => 0,
            'exceptions' => false,
            'cache_wsdl' => WSDL_CACHE_NONE
    $sMensagem1 = '
    $aResponse = $client->call('SimpleIsMember',$sMensagem1);
    $aData = array('dados'=>$aResponse->xpto, 'success'=>$aResponse->example);
return json_encode($aData);

Invoking a static method using reflection

String methodName= "...";
String[] args = {};

Method[] methods = clazz.getMethods();
for (Method m : methods) {
    if (methodName.equals(m.getName())) {
        // for static methods we can use null as instance of class
        m.invoke(null, new Object[] {args});

Why can't I find SQL Server Management Studio after installation?

Generally if the installation went smoothly, it will create the desktop icons/folders. Maybe check the installation summary log to see if there's any underlying errors.

It should be located C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Log(date stamp)\

Given a class, see if instance has method (Ruby)

Try Foo.instance_methods.include? :bar

How to change package name of Android Project in Eclipse?

One extremely important notice:

NEVER use a direct package names as in something similar to passing a string value containing the package name. Use the method getPackageName(). This will make the renaming dynamic. Do whatever to reach the method getPackageName().

In Eclipse Juno, the correct way of renaming is:

  1. Go and edit the manifest.
  2. Remove every old package name in the manifest.
  3. Put instead of the old package name, the new package name in every location inside the manifest. You might have classes (Activities that is) that need direct package name references.
  4. Save the manifest.
  5. Then right click the package name inside the project.
  6. Select "Refactor".
  7. Select "Rename".
  8. Type the new package name.
  9. Select "update references".
  10. Press OK and you're done and watch out also what should be done to replace the new name.
  11. Don't forget to also update the layout XML files with the new package name. You might have a custom View. Look for them.

jQuery .live() vs .on() method for adding a click event after loading dynamic html

I used 'live' in my project but one of my friend suggested that i should use 'on' instead of live. And when i tried to use that i experienced a problem like you had.

On my pages i create buttons table rows and many dom stuff dynamically. but when i use on the magic disappeared.

The other solutions like use it like a child just calls your functions every time on every click. But i find a way to make it happen again and here is the solution.

Write your code as:

function caller(){
    $('.ObjectYouWntToCall').on("click", function() {...magic...});

Call caller(); after you create your object in the page like this.

$('<dom class="ObjectYouWntToCall">bla... bla...<dom>').appendTo("#whereeveryouwant");

By this way your function is called when it is supposed to not every click on the page.

What's wrong with foreign keys?

I always use them, but then I make databases for financial systems. The database is the critical part of the application. If the data in a financial database isn't totally accurate then it really doesn't matter how much effort you put into your code/front-end design. You're just wasting your time.

There's also the fact that multiple systems generally need to interface directly with the database - from other systems that just read data out (Crystal Reports) to systems that insert data (not necessarily using an API I've designed; it may be written by a dull-witted manager who has just discovered VBScript and has the SA password for the SQL box). If the database isn't as idiot-proof as it can possibly be, well - bye bye database.

If your data is important, then yes, use foreign keys, create a suite of stored procedures to interact with the data, and make the toughest DB you can. If your data isn't important, why are you making a database to begin with?

How can I list ALL grants a user received?

If you want more than just direct table grants (e.g., grants via roles, system privileges such as select any table, etc.), here are some additional queries:

System privileges for a user:

  FROM sys.dba_sys_privs
 WHERE grantee = <theUser>
  FROM dba_role_privs rp JOIN role_sys_privs rsp ON (rp.granted_role = rsp.role)
 WHERE rp.grantee = <theUser>

Direct grants to tables/views:

SELECT owner, table_name, select_priv, insert_priv, delete_priv, update_priv, references_priv, alter_priv, index_priv 
  FROM table_privileges
 WHERE grantee = <theUser>
 ORDER BY owner, table_name;

Indirect grants to tables/views:

  FROM dba_role_privs rp JOIN role_tab_privs rtp ON (rp.granted_role = rtp.role)
 WHERE rp.grantee = <theUser>
 ORDER BY owner, table_name;

How to execute XPath one-liners from shell?

My Python script does exactly this. In order to search for all attributes attribute of elements element in files filename.xml ..., you would run it as follows: "//element/@attribute" filename.xml ...

There are various switches for controlling the output, such as -c for counting matches, -i for indenting the matching parts, and -l for outputting filenames only.

The script is not available as a Debian or Ubuntu package, but all of its dependencies are.

Expand and collapse with angular js

You can solve this fully in the html:

  <input ng-model=collapse type=checkbox>Title
  <div ng-show=collapse>
     Only shown when checkbox is clicked

This also works well with ng-repeat since it will create a local scope for each member.

  <tbody ng-repeat='m in members'>
       <td><input type=checkbox ng-model=collapse></td>
    <tr ng-show=collapse>
      <td> </td>
      <td>{{ m.content }}</td>

Be aware that even though a repeat has its own scope, initially it will inherit the value from collapse from super scopes. This allows you to set the initial value in one place but it can be surprising.

You can of course restyle the checkbox. See

Updated fiddle: Original fiddle used closing </input> tags to add the HTML text label instead of using <label> tags.

XAMPP installation on Win 8.1 with UAC Warning

You can solve this problem by installing xampp in different Drive .Instead of C Drive .

Iterating over Typescript Map

You can also apply the array map method to the Map.entries() iterable:

     ([key, value]: [string, number]) => console.log(key, value)

Also, as noted in other answers, you may have to enable down level iteration in your tsconfig.json (under compiler options):

  "downlevelIteration": true,

T-SQL STOP or ABORT command in SQL Server

To work around the RETURN/GO issue you could put RAISERROR ('Oi! Stop!', 20, 1) WITH LOG at the top.

This will close the client connection as per RAISERROR on MSDN.

The very big downside is you have to be sysadmin to use severity 20.


A simple demonstration to counter Jersey Dude's comment...

RAISERROR ('Oi! Stop!', 20, 1)  WITH LOG
SELECT 'Will not run'
SELECT 'Will not run'
SELECT 'Will not run'

checking memory_limit in PHP

Command line to check ini:

$ php -r "echo ini_get('memory_limit');"

Accessing AppDelegate from framework?

If you're creating a framework the whole idea is to make it portable. Tying a framework to the app delegate defeats the purpose of building a framework. What is it you need the app delegate for?

Struct Constructor in C++?

Note that there is one interesting difference (at least with the MS C++ compiler):

If you have a plain vanilla struct like this

struct MyStruct {
   int id;
   double x;
   double y;

then somewhere else you might initialize an array of such objects like this:

MYSTRUCT _pointList[] = { 
   { 1, 1.0, 1.0 }, 
   { 2, 1.0, 2.0 }, 
   { 3, 2.0, 1.0 }

however, as soon as you add a user-defined constructor to MyStruct such as the ones discussed above, you'd get an error like this:

    'MyStruct' : Types with user defined constructors are not aggregate
     <file and line> : error C2552: '_pointList' : non-aggregates cannot 
     be initialized with initializer list.

So that's at least one other difference between a struct and a class. This kind of initialization may not be good OO practice, but it appears all over the place in the legacy WinSDK c++ code that I support. Just so you know...

How to have click event ONLY fire on parent DIV, not children?

You can use bubbling in your favor:

$('.foobar').on('click', function(e) {
    // do your thing.
}).on('click', 'div', function(e) {
    // clicked on descendant div


use this

mysql> SELECT TRUNCATE(223.69, 0);
        > 223

Here's a link

Select multiple columns using Entity Framework

You can select to an anonymous type, for example

var dataset2 = 
    (from recordset in entities.processlists 
    where recordset.ProcessName == processname 
    select new
        serverName = recordset.ServerName,
        processId = recordset.ProcessID, 
        username = recordset.Username

Or you can create a new class that will represent your selection, for example

public class MyDataSet
    public string ServerName { get; set; }
    public string ProcessId { get; set; }
    public string Username { get; set; }

then you can for example do the following

 var dataset2 = 
    (from recordset in entities.processlists 
    where recordset.ProcessName == processname 
    select new MyDataSet
        ServerName = recordset.ServerName,
        ProcessId = recordset.ProcessID, 
        Username = recordset.Username

How to get history on react-router v4?

Similiary to accepted answer what you could do is use react and react-router itself to provide you history object which you can scope in a file and then export.


import React from 'react';
import { withRouter } from 'react-router';

// variable which will point to react-router history
let globalHistory = null;

// component which we will mount on top of the app
class Spy extends React.Component {
  constructor(props) {
    globalHistory = props.history; 

  componentDidUpdate() {
    globalHistory = this.props.history;

    return null;

export const GlobalHistory = withRouter(Spy);

// export react-router history
export default function getHistory() {    
  return globalHistory;

You later then import Component and mount to initialize history variable:

import { BrowserRouter } from 'react-router-dom';
import { GlobalHistory } from './history';

function render() {
            <GlobalHistory />

And then you can just import in your app when it has been mounted:

import getHistory from './history'; 

export const goToPage = () => (dispatch) => {
  dispatch({ type: GO_TO_SUCCESS_PAGE });
  getHistory().push('/success'); // at this point component probably has been mounted and we can safely get `history`

I even made and npm package that does just that.

Scroll to the top of the page after render in react.js

This could, and probably should, be handled using refs:

"... you can use ReactDOM.findDOMNode as an "escape hatch" but we don't recommend it since it breaks encapsulation and in almost every case there's a clearer way to structure your code within the React model."

Example code:

class MyComponent extends React.Component {
    componentDidMount() {
        this._div.scrollTop = 0

    render() {
        return <div ref={(ref) => this._div = ref} />

Regex for string contains?

Assuming regular PCRE-style regex flavors:

If you want to check for it as a single, full word, it's \bTest\b, with appropriate flags for case insensitivity if desired and delimiters for your programming language. \b represents a "word boundary", that is, a point between characters where a word can be considered to start or end. For example, since spaces are used to separate words, there will be a word boundary on either side of a space.

If you want to check for it as part of the word, it's just Test, again with appropriate flags for case insensitivity. Note that usually, dedicated "substring" methods tend to be faster in this case, because it removes the overhead of parsing the regex.

find index of an int in a list

It's even easier if you consider that the Generic List in C# is indexed from 0 like an array. This means you can just use something like:

int index = 0; int i = accounts[index];

C++ String Concatenation operator<<

You can combine strings using stream string like that:

#include <iostream>
#include <sstream>
using namespace std;
int main()
    string name = "Bill";
    stringstream ss;
    ss << "Your name is: " << name;
    string info = ss.str();
    cout << info << endl;
    return 0;

Complex nesting of partials and templates

I too was struggling with nested views in Angular.

Once I got a hold of ui-router I knew I was never going back to angular default routing functionality.

Here is an example application that uses multiple levels of views nesting

app.config(function ($stateProvider, $urlRouterProvider,$httpProvider) {
// navigate to view1 view by default

    .state('view1', {
        url: '/view1',
        templateUrl: 'partials/view1.html',
        controller: 'view1.MainController'
    .state('view1.nestedViews', {
        url: '/view1',
        views: {
            'childView1': { templateUrl: 'partials/view1.childView1.html' , controller: 'childView1Ctrl'},
            'childView2': { templateUrl: 'partials/view1.childView2.html', controller: 'childView2Ctrl' },
            'childView3': { templateUrl: 'partials/view1.childView3.html', controller: 'childView3Ctrl' }

    .state('view2', {
        url: '/view2',

    .state('view3', {
        url: '/view3',

    .state('view4', {
        url: '/view4',

As it can be seen there are 4 main views (view1,view2,view3,view4) and view1 has 3 child views.

React Error: Target Container is not a DOM Element

Also, the best practice of moving your <script></script> to the bottom of the html file fixes this too.

How do I get the collection of Model State Errors in ASP.NET MVC?

Thanks Chad! To show all the errors associated with the key, here's what I came up with. For some reason the base Html.ValidationMessage helper only shows the first error associated with the key.

    <%= Html.ShowAllErrors(mykey) %>


    public static String ShowAllErrors(this HtmlHelper helper, String key) {
        StringBuilder sb = new StringBuilder();
        if (helper.ViewData.ModelState[key] != null) {
            foreach (var e in helper.ViewData.ModelState[key].Errors) {
                TagBuilder div = new TagBuilder("div");
                div.MergeAttribute("class", "field-validation-error");
        return sb.ToString();