Programs & Examples On #Yellow screen of death

Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays

*********** PARSE THE RESULT TO JSON OBJECT: JSON.prase(result.arrayOfObjects) ***********

I came to this page after I faced this issue. So, my issue was that the server is sending array of objects in the form of string. It is something like this:

when I printed result on console after getting from server it is string:

'arrayOfObject': '[
                  {'id': '123', 'designation': 'developer'},
                  {'id': '422', 'designation': 'lead'}
               ]'

So, I have to convert this string to JSON after getting it from server. Use method for parsing the result string that you receive from server:

JSON.parse(result.arrayOfObjects)

How to deal with the URISyntaxException

A space is encoded to %20 in URLs, and to + in forms submitted data (content type application/x-www-form-urlencoded). You need the former.

Using Guava:

dependencies {
     compile 'com.google.guava:guava:28.1-jre'
}

You can use UrlEscapers:

String encodedString = UrlEscapers.urlFragmentEscaper().escape(inputString);

Don't use String.replace, this would only encode the space. Use a library instead.

Running a simple shell script as a cronjob

The easiest way would be to use a GUI:

For Gnome use gnome-schedule (universe)

sudo apt-get install gnome-schedule 

For KDE use kde-config-cron

It should be pre installed on Kubuntu

But if you use a headless linux or don´t want GUI´s you may use:

crontab -e

If you type it into Terminal you´ll get a table.
You have to insert your cronjobs now.
Format a job like this:

*     *     *     *     *  YOURCOMMAND
-     -     -     -     -
|     |     |     |     |
|     |     |     |     +----- Day in Week (0 to 7) (Sunday is 0 and 7)
|     |     |     +------- Month (1 to 12)
|     |     +--------- Day in Month (1 to 31)
|     +----------- Hour (0 to 23)
+------------- Minute (0 to 59)

There are some shorts, too (if you don´t want the *):

@reboot --> only once at startup
@daily ---> once a day
@midnight --> once a day at midnight
@hourly --> once a hour
@weekly --> once a week
@monthly --> once a month
@annually --> once a year
@yearly --> once a year

If you want to use the shorts as cron (because they don´t work or so):

@daily --> 0 0 * * *
@midnight --> 0 0 * * *
@hourly --> 0 * * * *
@weekly --> 0 0 * * 0
@monthly --> 0 0 1 * *
@annually --> 0 0 1 1 *
@yearly --> 0 0 1 1 *

Bash scripting missing ']'

If you created your script on windows and want to run it on linux machine, and you're sure there is no mistake in your code, install dos2unix on linux machine and run dos2unix yourscript.sh. Then, run the script.

How can I specify a display?

I through vnc to understand the X11 more. To specify the display to get a many-displayed program, export DISPLAY=IP:DisplayNum.ScreenNum

For example,

vncserver :2
vncserver -list
echo '$DISPLAY'=$DISPLAY 
export DISPLAY=:2  # export DISPLAY=IP:DisplayNum or export DISPLAY=:DisplayNum for localhost; So that can vnc connect and see the vnc desktop :2 if $DISPLAY is not :2.
echo '$DISPLAY'=$DISPLAY

convert ArrayList<MyCustomClass> to JSONArray

Use Gson library to convert ArrayList to JsonArray.

Gson gson = new GsonBuilder().create();
JsonArray myCustomArray = gson.toJsonTree(myCustomList).getAsJsonArray();

What does "both" mean in <div style="clear:both">

Description of the possible values:

  • left: No floating elements allowed on the left side
  • right: No floating elements allowed on the right side
  • both: No floating elements allowed on either the left or the right side
  • none: Default. Allows floating elements on both sides
  • inherit: Specifies that the value of the clear property should be inherited from the parent element

Source: w3schools.com

Change Background color (css property) using Jquery

You're using a colon instead of a comma. Try:

$(body).css("background-color","blue");

You also need to wrap the id in quotes or it will look for a variable called #co

$("#co").click(change()

There are many more issues here. click isn't an HTML attribute. You want onclick (which is redundant). Try this:

<div id="co"> <!-- no onclick method needed -->
<script>
$(document).ready(function() {
    $("#co").click(function() {
        $("body").css("background-color","blue"); //edit, body must be in quotes!
    });
});
</script>

You were trying to call an undefined method. It looks like you were trying to declare it inside the callback statement? I'm not sure. But please compare this to your code and see the differences.

http://jsfiddle.net/CLwE5/ demo fiddle

Changing image size in Markdown

You could use this one as well with kramdown:

markdown
![drawing](drawing.jpg)   
{:.some-css-class style="width: 200px"}

or

markdown
![drawing](drawing.jpg)   
{:.some-css-class width="200"}

This way you can directly add arbitrary attributes to the last html element. To add classes there is a shortcut .class.secondclass.

Limit number of characters allowed in form input text field

You can use <input type = "text" maxlength="9"> or

<input type = "number" maxlength="9"> for numbers or <input type = "email" maxlength="9"> for email validation will show up

JPA or JDBC, how are they different?

Main difference between JPA and JDBC is level of abstraction.

JDBC is a low level standard for interaction with databases. JPA is higher level standard for the same purpose. JPA allows you to use an object model in your application which can make your life much easier. JDBC allows you to do more things with the Database directly, but it requires more attention. Some tasks can not be solved efficiently using JPA, but may be solved more efficiently with JDBC.

Display / print all rows of a tibble (tbl_df)

i prefer to physically print my tables instead:

CONNECT_SERVER="https://196.168.1.1/"
CONNECT_API_KEY<-"hpphotosmartP9000:8273827"

data.frame = data.frame(1:1000, 1000:2)

connectServer <- Sys.getenv("CONNECT_SERVER")
apiKey <- Sys.getenv("CONNECT_API_KEY")

install.packages('print2print')

print2print::send2printer(connectServer, apiKey, data.frame)

ConcurrentModificationException for ArrayList

Like the other answers say, you can't remove an item from a collection you're iterating over. You can get around this by explicitly using an Iterator and removing the item there.

Iterator<Item> iter = list.iterator();
while(iter.hasNext()) {
  Item blah = iter.next();
  if(...) {
    iter.remove(); // Removes the 'current' item
  }
}

Cannot execute RUN mkdir in a Dockerfile

You can also simply use

WORKDIR /var/www/app

It will automatically create the folders if they don't exist.

Then switch back to the directory you need to be in.

Is there a macro to conditionally copy rows to another worksheet?

Here's another solution that uses some of VBA's built in date functions and stores all the date data in an array for comparison, which may give better performance if you get a lot of data:

Public Sub MoveData(MonthNum As Integer, FromSheet As Worksheet, ToSheet As Worksheet)
    Const DateCol = "A" 'column where dates are store
    Const DestCol = "A" 'destination column where dates are stored. We use this column to find the last populated row in ToSheet
    Const FirstRow = 2 'first row where date data is stored
    'Copy range of values to Dates array
    Dates = FromSheet.Range(DateCol & CStr(FirstRow) & ":" & DateCol & CStr(FromSheet.Range(DateCol & CStr(FromSheet.Rows.Count)).End(xlUp).Row)).Value
    Dim i As Integer
    For i = LBound(Dates) To UBound(Dates)
        If IsDate(Dates(i, 1)) Then
            If Month(CDate(Dates(i, 1))) = MonthNum Then
                Dim CurrRow As Long
                'get the current row number in the worksheet
                CurrRow = FirstRow + i - 1
                Dim DestRow As Long
                'get the destination row
                DestRow = ToSheet.Range(DestCol & CStr(ToSheet.Rows.Count)).End(xlUp).Row + 1
                'copy row CurrRow in FromSheet to row DestRow in ToSheet
                FromSheet.Range(CStr(CurrRow) & ":" & CStr(CurrRow)).Copy ToSheet.Range(DestCol & CStr(DestRow))
            End If
        End If
    Next i
End Sub

Cannot attach the file *.mdf as database

Just change database name from web.config project level file and then update database.

connectionString = Data Source =(LocalDb)\MSSQLLocalDB;AttachDbFilename="|DataDirectory|\aspnet-Project name-20180413070506.mdf";Initial Catalog="aspnet--20180413070506";Integrated

Change the bold digit to some other number:

connectionString = Data Source==(LocalDb)\MSSQLLocalDB;AttachDbFilename="|DataDirectory|\aspnet-Project name-20180413070507.mdf";Initial Catalog="aspnet--20180413070507";Integrated

How do I get the Date & Time (VBS)

To expound on Numenor's answer you can do something like, Format(Now(),"HH:mm:ss") using these custom date/time formating options


For everyone who is tempted to downvote this answer please be aware that the question was originally tagged VB and vbscript hence my answer, the VB tag was edited out leaving only the vbscript tag. The OP accepted this answer which I take to mean that it gave him the information that he needed.

Java: int[] array vs int array[]

Both are the same. I usually use int[] array = new int[10];, because of better (contiguous) readability of the type int[].

Sass calculate percent minus px

Sass cannot perform arithmetic on values that cannot be converted from one unit to the next. Sass has no way of knowing exactly how wide "100%" is in terms of pixels or any other unit. That's something only the browser knows.

You need to use calc() instead. Check browser compatibility on Can I use...

.foo {
    height: calc(25% - 5px);
}

If your values are in variables, you may need to use interpolation turn them into strings (otherwise Sass just tries to perform arithmetic):

$a: 25%;
$b: 5px;

.foo {
  width: calc(#{$a} - #{$b});
}

What is fastest children() or find() in jQuery?

Those won't necessarily give the same result: find() will get you any descendant node, whereas children() will only get you immediate children that match.

At one point, find() was a lot slower since it had to search for every descendant node that could be a match, and not just immediate children. However, this is no longer true; find() is much quicker due to using native browser methods.

Java: How to insert CLOB into oracle database

This code worked for me. I use ojdbc6-11.2.0.2.jar.

java.sql.Connection con;
javax.xml.bind.Marshaller marshaller;

Clob xmlClob = con.createClob();
try {
  try (Writer xmlClobWriter = xmlClob.setCharacterStream(1)) {
    m.marshal(jaxbObject, xmlClobWriter);
  } // xmlClobWriter.close();
  try (PreparedStatement stmt = con.prepareStatement("INSERT INTO table (xml) values(?)")) {
    stmt.setClob(1, xmlClob);
    stmt.executeUpdate();
  }
} finally {
  xmlClob.free();
}

Task<> does not contain a definition for 'GetAwaiter'

Just experienced this in a method that executes a linq query.

public async Task<Foo> GetSomething()
{
    return await (from foo in Foos
                  select foo).FirstOrDefault();
}

Needed to use .FirstOrDefaultAsync() instead. N00b mistake.

Trouble Connecting to sql server Login failed. "The login is from an untrusted domain and cannot be used with Windows authentication"

I started to get this error when i tried to login to SSMS using 'windows Authentication'. This started to happen after i renamed the Windows SQL server. I tried everything to resolve this error and in my particular case changing the machine names in the 'hosts' file to reflect the name SQL server name change resolved the issue. C:\Windows\System32\Drivers\etc\hosts

Maven: How to run a .java file from command line passing arguments

In addition to running it with mvn exec:java, you can also run it with mvn exec:exec

mvn exec:exec -Dexec.executable="java" -Dexec.args="-classpath %classpath your.package.MainClass"

printf, wprintf, %s, %S, %ls, char* and wchar*: Errors not announced by a compiler warning?

Answer A

None of the answers above pointed out why you might not see some of your prints. This is also because here you are dealing with streams (I didn't know this) and stream has something called orientation. Let me cite something from this source:

Narrow and wide orientation

A newly opened stream has no orientation. The first call to any I/O function establishes the orientation.

A wide I/O function makes the stream wide-oriented, a narrow I/O function makes the stream narrow-oriented. Once set, the orientation can only be changed with freopen.

Narrow I/O functions cannot be called on a wide-oriented stream; wide I/O functions cannot be called on a narrow-oriented stream. Wide I/O functions convert between wide and multibyte characters as if by calling mbrtowc and wcrtomb. Unlike the multibyte character strings that are valid in a program, multibyte character sequences in the file may contain embedded nulls and do not have to begin or end in the initial shift state.

So once you use printf() your orientation becomes narrow and from this point on you can't get anything out of wprintf() and you realy don't. Unless you use freeopen() which is intended to be used on files.


Answer B

As it turns out you can use freeopen() like this:

freopen(NULL, "w", stdout);             

To make stream "not defined" again. Try this example:

#include <stdio.h>
#include <wchar.h>
#include <locale.h>

int main(void)
{
    // We set locale which is the same as the enviromental variable "LANG=en_US.UTF-8".
    setlocale(LC_ALL, "en_US.UTF-8");

    // We define array of wide characters. We indicate this on both sides of equal sign
    // with "wchar_t" on the left and "L" on the right.
    wchar_t y[100] = L"€? ???a??p???? e? a??? est??\n";

    // We print header in ASCII characters
    wprintf(L"content-type:text/html; charset:utf-8\n\n");

    // A newly opened stream has no orientation. The first call to any I/O function
    // establishes the orientation: a wide I/O function makes the stream wide-oriented,
    // a narrow I/O function makes the stream narrow-oriented. Once set, we must respect
    // this, so for the time being we are stuck with either printf() or wprintf().

    wprintf(L"%S\n", y);    // Conversion specifier %S is not standardized (!)
    wprintf(L"%ls\n", y);   // Conversion specifier %s with length modifier %l is 
                            // standardized (!)

    // At this point curent orientation of the stream is wide and this is why folowing
    // narrow function won't print anything! Whether we should use wprintf() or printf()
    // is primarily a question of how we want output to be encoded.

    printf("1\n");          // Print narrow string of characters with a narrow function
    printf("%s\n", "2");    // Print narrow string of characters with a narrow function
    printf("%ls\n",L"3");   // Print wide string of characters with a narrow function

    // Now we reset the stream to no orientation.
    freopen(NULL, "w", stdout);

    printf("4\n");          // Print narrow string of characters with a narrow function
    printf("%s\n", "5");    // Print narrow string of characters with a narrow function
    printf("%ls\n",L"6");   // Print wide string of characters with a narrow function

    return 0;
}

Group By Multiple Columns

C# 7.1 or greater using Tuples and Inferred tuple element names (currently it works only with linq to objects and it is not supported when expression trees are required e.g. someIQueryable.GroupBy(...). Github issue):

// declarative query syntax
var result = 
    from x in inMemoryTable
    group x by (x.Column1, x.Column2) into g
    select (g.Key.Column1, g.Key.Column2, QuantitySum: g.Sum(x => x.Quantity));

// or method syntax
var result2 = inMemoryTable.GroupBy(x => (x.Column1, x.Column2))
    .Select(g => (g.Key.Column1, g.Key.Column2, QuantitySum: g.Sum(x => x.Quantity)));

C# 3 or greater using anonymous types:

// declarative query syntax
var result3 = 
    from x in table
    group x by new { x.Column1, x.Column2 } into g
    select new { g.Key.Column1, g.Key.Column2, QuantitySum = g.Sum(x => x.Quantity) };

// or method syntax
var result4 = table.GroupBy(x => new { x.Column1, x.Column2 })
    .Select(g => 
      new { g.Key.Column1, g.Key.Column2 , QuantitySum= g.Sum(x => x.Quantity) });

PostgreSQL database service

I'm not on windows, but I think you can use the pgAdmin you just installed to configure a server connection and start the server.

Check if key exists in JSON object using jQuery

No need of JQuery simply you can do

if(yourObject['email']){
 // what if this property exists.
}

as with any value for email will return you true, if there is no such property or that property value is null or undefined will result to false

equals vs Arrays.equals in Java

Look inside the implementation of the two methods to understand them deeply:

array1.equals(array2);
/**
 * Indicates whether some other object is "equal to" this one.
 * <p>
 * The {@code equals} method implements an equivalence relation
 * on non-null object references:
 * <ul>
 * <li>It is <i>reflexive</i>: for any non-null reference value
 *     {@code x}, {@code x.equals(x)} should return
 *     {@code true}.
 * <li>It is <i>symmetric</i>: for any non-null reference values
 *     {@code x} and {@code y}, {@code x.equals(y)}
 *     should return {@code true} if and only if
 *     {@code y.equals(x)} returns {@code true}.
 * <li>It is <i>transitive</i>: for any non-null reference values
 *     {@code x}, {@code y}, and {@code z}, if
 *     {@code x.equals(y)} returns {@code true} and
 *     {@code y.equals(z)} returns {@code true}, then
 *     {@code x.equals(z)} should return {@code true}.
 * <li>It is <i>consistent</i>: for any non-null reference values
 *     {@code x} and {@code y}, multiple invocations of
 *     {@code x.equals(y)} consistently return {@code true}
 *     or consistently return {@code false}, provided no
 *     information used in {@code equals} comparisons on the
 *     objects is modified.
 * <li>For any non-null reference value {@code x},
 *     {@code x.equals(null)} should return {@code false}.
 * </ul>
 * <p>
 * The {@code equals} method for class {@code Object} implements
 * the most discriminating possible equivalence relation on objects;
 * that is, for any non-null reference values {@code x} and
 * {@code y}, this method returns {@code true} if and only
 * if {@code x} and {@code y} refer to the same object
 * ({@code x == y} has the value {@code true}).
 * <p>
 * Note that it is generally necessary to override the {@code hashCode}
 * method whenever this method is overridden, so as to maintain the
 * general contract for the {@code hashCode} method, which states
 * that equal objects must have equal hash codes.
 *
 * @param   obj   the reference object with which to compare.
 * @return  {@code true} if this object is the same as the obj
 *          argument; {@code false} otherwise.
 * @see     #hashCode()
 * @see     java.util.HashMap
 */
public boolean equals(Object obj) {
    return (this == obj);
}

while:

Arrays.equals(array1, array2);
/**
 * Returns <tt>true</tt> if the two specified arrays of Objects are
 * <i>equal</i> to one another.  The two arrays are considered equal if
 * both arrays contain the same number of elements, and all corresponding
 * pairs of elements in the two arrays are equal.  Two objects <tt>e1</tt>
 * and <tt>e2</tt> are considered <i>equal</i> if <tt>(e1==null ? e2==null
 * : e1.equals(e2))</tt>.  In other words, the two arrays are equal if
 * they contain the same elements in the same order.  Also, two array
 * references are considered equal if both are <tt>null</tt>.<p>
 *
 * @param a one array to be tested for equality
 * @param a2 the other array to be tested for equality
 * @return <tt>true</tt> if the two arrays are equal
 */
public static boolean equals(Object[] a, Object[] a2) {
    if (a==a2)
        return true;
    if (a==null || a2==null)
        return false;

    int length = a.length;
    if (a2.length != length)
        return false;

    for (int i=0; i<length; i++) {
        Object o1 = a[i];
        Object o2 = a2[i];
        if (!(o1==null ? o2==null : o1.equals(o2)))
            return false;
    }

    return true;
}

Getting the size of an array in an object

Arrays have a property .length that returns the number of elements.

var st =
    {
        "itema":{},
        "itemb":
        [
            {"id":"s01","cd":"c01","dd":"d01"},
            {"id":"s02","cd":"c02","dd":"d02"}
        ]
    };

st.itemb.length // 2

jQuery, checkboxes and .is(":checked")

if ($.browser.msie) {
    $("#myCheckbox").click(function() { $(this).trigger('change'); });
}

$("#myCheckbox").change(function() {
        alert($(this).is(":checked"));
    });

Get specific objects from ArrayList when objects were added anonymously?

As per your question requirement , I would like to suggest that Map will solve your problem very efficient and without any hassle.

In Map you can give the name as key and your original object as value.

  Map<String,Cave> myMap=new HashMap<String,Cave>();

Restoring Nuget References?

In Visual Studio 2015 (Soulution is under source control, MVC-Project), csano's Update-Package -Reinstall -ProjectName Your.Project.Name worked, but it messed up with some write locks.

I had to delete the "packages"-Folder manually before. (It seemed to be locked because of the source control).

Also, I had to re-install the MVC-Package from the NuGet Package Manager.

Configuring Git over SSH to login once

If you have cloned using HTTPS (recommended) then:-

git config --global credential.helper cache

and then

git config --global credential.helper 'cache --timeout=2592000'
  • timeout=2592000 (30 Days in seconds) to enable caching for 30 days (or whatever suites you).

  • Now run a simple git command that requires your username and password.

  • Enter your credentials once and now caching is enabled for 30 Days.

  • Try again with any git command and now you don't need any credentials.

  • For more info :- Caching your GitHub password in Git

Note : You need Git 1.7.10 or newer to use the credential helper. On system restart, we might have to enter the password again.

Update #1:

If you are receiving this error git: 'credential-cache' is not a git command. See 'get --help'

then replace git config --global credential.helper 'cache --timeout=2592000'

with git config --global credential.helper 'store --file ~/.my-credentials'

Update #2:

If you keep getting the prompt of username and password and getting this issue:

Logon failed, use ctrl+c to cancel basic credential prompt.

Reinstalling the latest version of git worked for me.

How to remove new line characters from data rows in mysql?

your syntax is wrong:

update mytable SET title = TRIM(TRAILING '\n' FROM title)

Addition:

If the newline character is at the start of the field:

update mytable SET title = TRIM(LEADING '\n' FROM title)

Use of Finalize/Dispose method in C#

nobody answered the question about whether you should implement IDisposable even though you dont need it.

Short answer : No

Long answer:

This would allow a consumer of your class to use 'using'. The question I would ask is - why would they do it? Most devs will not use 'using' unless they know that they must - and how do they know. Either

  • its obviuos the them from experience (a socket class for example)
  • its documented
  • they are cautious and can see that the class implements IDisposable

So by implementing IDisposable you are telling devs (at least some) that this class wraps up something that must be released. They will use 'using' - but there are other cases where using is not possible (the scope of object is not local); and they will have to start worrying about the lifetime of the objects in those other cases - I would worry for sure. But this is not necessary

You implement Idisposable to enable them to use using, but they wont use using unless you tell them to.

So dont do it

tar: add all files and directories in current directory INCLUDING .svn and so on

Had a similar situation myself. I think it is best to create the tar elsewhere and then use -C to tell tar the base directory for the compressed files. Example:

tar -cjf workspace.tar.gz -C <path_to_workspace> $(ls -A <path_to_workspace>)

This way there is no need to exclude your own tarfile. As noted in other comments, -A will list hidden files.

How to move Docker containers between different hosts?

Alternatively, if you do not wish to push to a repository:

  1. Export the container to a tarball

    docker export <CONTAINER ID> > /home/export.tar
    
  2. Move your tarball to new machine

  3. Import it back

    cat /home/export.tar | docker import - some-name:latest
    

gcc error: wrong ELF class: ELFCLASS64

I think that coreset.o was compiled for 64-bit, and you are linking it with a 32-bit computation.o.

You can try to recompile computation.c with the '-m64' flag of gcc(1)

Get index of selected option with jQuery

selectedIndex is a JavaScript Select Property. For jQuery you can use this code:

jQuery(document).ready(function($) {
  $("#dropDownMenuKategorie").change(function() {
    // I personally prefer using console.log(), but if you want you can still go with the alert().
    console.log($(this).children('option:selected').index());
  });
});

Send and receive messages through NSNotificationCenter in Objective-C?

SWIFT 5.1 of selected answer for newbies

class TestClass {
    deinit {
        // If you don't remove yourself as an observer, the Notification Center
        // will continue to try and send notification objects to the deallocated
        // object.
        NotificationCenter.default.removeObserver(self)
    }

    init() {
        super.init()

        // Add this instance of TestClass as an observer of the TestNotification.
        // We tell the notification center to inform us of "TestNotification"
        // notifications using the receiveTestNotification: selector. By
        // specifying object:nil, we tell the notification center that we are not
        // interested in who posted the notification. If you provided an actual
        // object rather than nil, the notification center will only notify you
        // when the notification was posted by that particular object.

        NotificationCenter.default.addObserver(self, selector: #selector(receiveTest(_:)), name: NSNotification.Name("TestNotification"), object: nil)
    }

    @objc func receiveTest(_ notification: Notification?) {
        // [notification name] should always be @"TestNotification"
        // unless you use this method for observation of other notifications
        // as well.

        if notification?.name.isEqual(toString: "TestNotification") != nil {
            print("Successfully received the test notification!")
        }
    }
}

... somewhere else in another class ...

 func someMethod(){
        // All instances of TestClass will be notified
        NotificationCenter.default.post(name: NSNotification.Name(rawValue: "TestNotification"), object: self)
 }

How to upload files on server folder using jsp

You cannot upload like this.

http://grand-shopping.com/<"some folder">

You need a physical path exactly like in your local

C:/Users/puneet verma/Downloads/

What you can do is create some local path where your server is working. Hence you can store and retrieve the file. If you bought some domain from any websites there will be path to upload the files. You create these variable as static constant and use it based on the server you are working (Local/Website).

Converting year and month ("yyyy-mm" format) to a date?

Try this. (Here we use text=Lines to keep the example self contained but in reality we would replace it with the file name.)

Lines <- "2009-01  12
2009-02  310
2009-03  2379
2009-04  234
2009-05  14
2009-08  1
2009-09  34
2009-10  2386"

library(zoo)
z <- read.zoo(text = Lines, FUN = as.yearmon)
plot(z)

The X axis is not so pretty with this data but if you have more data in reality it might be ok or you can use the code for a fancy X axis shown in the examples section of ?plot.zoo .

The zoo series, z, that is created above has a "yearmon" time index and looks like this:

> z
Jan 2009 Feb 2009 Mar 2009 Apr 2009 May 2009 Aug 2009 Sep 2009 Oct 2009 
      12      310     2379      234       14        1       34     2386 

"yearmon" can be used alone as well:

> as.yearmon("2000-03")
[1] "Mar 2000"

Note:

  1. "yearmon" class objects sort in calendar order.

  2. This will plot the monthly points at equally spaced intervals which is likely what is wanted; however, if it were desired to plot the points at unequally spaced intervals spaced in proportion to the number of days in each month then convert the index of z to "Date" class: time(z) <- as.Date(time(z)) .

Permutations between two lists of unequal length

Answering the question "given two lists, find all possible permutations of pairs of one item from each list" and using basic Python functionality (i.e., without itertools) and, hence, making it easy to replicate for other programming languages:

def rec(a, b, ll, size):
    ret = []
    for i,e in enumerate(a):
        for j,f in enumerate(b):
            l = [e+f]
            new_l = rec(a[i+1:], b[:j]+b[j+1:], ll, size)
            if not new_l:
                ret.append(l)
            for k in new_l:
                l_k = l + k
                ret.append(l_k)
                if len(l_k) == size:
                    ll.append(l_k)
    return ret

a = ['a','b','c']
b = ['1','2']
ll = []
rec(a,b,ll, min(len(a),len(b)))
print(ll)

Returns

[['a1', 'b2'], ['a1', 'c2'], ['a2', 'b1'], ['a2', 'c1'], ['b1', 'c2'], ['b2', 'c1']]

iOS - Build fails with CocoaPods cannot find header files

If none of the above worked for you and you are finding this error because you just switched to use_frameworks! in your Podfile, read on:

I tried all the solutions above and a lot more before learning that it isn't about search header paths at all in my particular case; it's that when you switch to use_frameworks! in your Podfile you no longer need to include frameworks in your bridging header, and in fact Xcode will throw the very unhelpful "unable to find header" error.

What you need to do is remove all imports from your bridging header file, and instead use the Swift import Module in your individual Swift files as needed, just like you would for Swift frameworks.

AND if you are using any of the framework headers in your Obj-C classes (in my case we have a convenience class that used the FBSDK) you need to change it from a local to global import (this means change #import "Module.h" to #import <Module/Module.h>, which should autocomplete for you when you begin to type the framework name. In my case it was <AFNetworking/AFHTTPRequestOperationManager.h>).

Edit: I've since learned that doing an @import Module uses the umbrella file which is even safer.

Better way to get type of a Javascript variable?

function getType(obj) {
    if(obj && obj.constructor && obj.constructor.name) {
        return obj.constructor.name;
    }
    return Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();
}

In my preliminary tests, this is working pretty well. The first case will print the name of any object created with "new", and the 2nd case should catch everything else.

I'm using (8, -1) because I'm assuming that the result is always going to start with [object and end with ] but I'm not certain that's true in every scenario.

The first day of the current month in php using date_modify as DateTime object

All those special php expressions, in spirit of first day of ... are great, though they go out of my head time and again.

So I decided to build a couple of basic datetime abstractions and tons of specific implementation which are auto-completed by any IDE. The point is to find what-kind of things. Like, today, now, the first day of a previous month, etc. All of those things I've listed are datetimes. Hence, there is an interface or abstract class called ISO8601DateTime, and specific datetimes which implement it.

The code in your particular case looks like that:

(new TheFirstDayOfThisMonth(new Now()))->value();

For more about this approach, take a look at this entry.

How to set array length in c# dynamically

Does is need to be an array? If you use an ArrayList or one of the other objects available in C#, you won't have this limitation to content with. Hashtable, IDictionnary, IList, etc.. all allow a dynamic number of elements.

Bootstrap $('#myModal').modal('show') is not working

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script><script type="text/javascript" src="//code.jquery.com/jquery-1.11.3.min.js"></script>

the first googleapis script is not working now a days use this second scripe given by jquery

I can't install intel HAXM

None of the suggestions worked on their own.

Here is what worked for me: chmod -R 777 $ANDROID_HOME

Then try to install it via android studio -> sdk manager. If its not there, reinstall latest version of Android studio over your current installation. HAXM will show up in SDK manager after that.

If you do not have ANDROID_HOME set, then YOU are part of the problem. The value of it can be found inside Android Studio project structure. On MAC, just type CMD ; and look at SDK Location on left.

Simply run chmod -R 775

Simple way to repeat a string

for the sake of readability and portability:

public String repeat(String str, int count){
    if(count <= 0) {return "";}
    return new String(new char[count]).replace("\0", str);
}

Restful API service

I know @Martyn does not want full code, but I think this annotation its good for this question:

10 Open Source Android Apps which every Android developer must look into

Foursquared for Android is open-source, and have an interesting code pattern interacting with the foursquare REST API.

set value of input field by php variable's value

One way to do it will be to move all the php code above the HTML, copy the result to a variable and then add the result in the <input> tag.
Try this -

<?php
//Adding the php to the top.
if(isset($_POST['submit']))
{
    $value1=$_POST['value1'];
    $value2=$_POST['value2'];
    $sign=$_POST['sign'];
    ...
        //Adding to $result variable
    if($sign=='-') {
      $result = $value1-$value2;
    }
    //Rest of your code...
}
?>
<html>
<!--Rest of your tags...-->
Result:<br><input type"text" name="result" value = "<?php echo (isset($result))?$result:'';?>">

Java client certificates over HTTPS/SSL

For me, this is what worked using Apache HttpComponents ~ HttpClient 4.x:

    KeyStore keyStore  = KeyStore.getInstance("PKCS12");
    FileInputStream instream = new FileInputStream(new File("client-p12-keystore.p12"));
    try {
        keyStore.load(instream, "helloworld".toCharArray());
    } finally {
        instream.close();
    }

    // Trust own CA and all self-signed certs
    SSLContext sslcontext = SSLContexts.custom()
        .loadKeyMaterial(keyStore, "helloworld".toCharArray())
        //.loadTrustMaterial(trustStore, new TrustSelfSignedStrategy()) //custom trust store
        .build();
    // Allow TLSv1 protocol only
    SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
        sslcontext,
        new String[] { "TLSv1" },
        null,
        SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER); //TODO
    CloseableHttpClient httpclient = HttpClients.custom()
        .setHostnameVerifier(SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER) //TODO
        .setSSLSocketFactory(sslsf)
        .build();
    try {

        HttpGet httpget = new HttpGet("https://localhost:8443/secure/index");

        System.out.println("executing request" + httpget.getRequestLine());

        CloseableHttpResponse response = httpclient.execute(httpget);
        try {
            HttpEntity entity = response.getEntity();

            System.out.println("----------------------------------------");
            System.out.println(response.getStatusLine());
            if (entity != null) {
                System.out.println("Response content length: " + entity.getContentLength());
            }
            EntityUtils.consume(entity);
        } finally {
            response.close();
        }
    } finally {
        httpclient.close();
    }

The P12 file contains the client certificate and client private key, created with BouncyCastle:

public static byte[] convertPEMToPKCS12(final String keyFile, final String cerFile,
    final String password)
    throws IOException, CertificateException, KeyStoreException, NoSuchAlgorithmException,
    NoSuchProviderException
{
    // Get the private key
    FileReader reader = new FileReader(keyFile);

    PEMParser pem = new PEMParser(reader);
    PEMKeyPair pemKeyPair = ((PEMKeyPair)pem.readObject());
    JcaPEMKeyConverter jcaPEMKeyConverter = new JcaPEMKeyConverter().setProvider("BC");
    KeyPair keyPair = jcaPEMKeyConverter.getKeyPair(pemKeyPair);

    PrivateKey key = keyPair.getPrivate();

    pem.close();
    reader.close();

    // Get the certificate
    reader = new FileReader(cerFile);
    pem = new PEMParser(reader);

    X509CertificateHolder certHolder = (X509CertificateHolder) pem.readObject();
    java.security.cert.Certificate x509Certificate =
        new JcaX509CertificateConverter().setProvider("BC")
            .getCertificate(certHolder);

    pem.close();
    reader.close();

    // Put them into a PKCS12 keystore and write it to a byte[]
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    KeyStore ks = KeyStore.getInstance("PKCS12", "BC");
    ks.load(null);
    ks.setKeyEntry("key-alias", (Key) key, password.toCharArray(),
        new java.security.cert.Certificate[]{x509Certificate});
    ks.store(bos, password.toCharArray());
    bos.close();
    return bos.toByteArray();
}

Creating all possible k combinations of n items in C++

If the number of the set would be within 32, 64 or a machine native primitive size, then you can do it with a simple bit manipulation.

template<typename T>
void combo(const T& c, int k)
{
    int n = c.size();
    int combo = (1 << k) - 1;       // k bit sets
    while (combo < 1<<n) {

        pretty_print(c, combo);

        int x = combo & -combo;
        int y = combo + x;
        int z = (combo & ~y);
        combo = z / x;
        combo >>= 1;
        combo |= y;
    }
}

this example calls pretty_print() function by the dictionary order.

For example. You want to have 6C3 and assuming the current 'combo' is 010110. Obviously the next combo MUST be 011001. 011001 is : 010000 | 001000 | 000001

010000 : deleted continuously 1s of LSB side. 001000 : set 1 on the next of continuously 1s of LSB side. 000001 : shifted continuously 1s of LSB to the right and remove LSB bit.

int x = combo & -combo;

this obtains the lowest 1.

int y = combo + x;

this eliminates continuously 1s of LSB side and set 1 on the next of it (in the above case, 010000 | 001000)

int z = (combo & ~y)

this gives you the continuously 1s of LSB side (000110).

combo = z / x;
combo >> =1;

this is for 'shifted continuously 1s of LSB to the right and remove LSB bit'.

So the final job is to OR y to the above.

combo |= y;

Some simple concrete example :

#include <bits/stdc++.h>

using namespace std;

template<typename T>
void pretty_print(const T& c, int combo)
{
    int n = c.size();
    for (int i = 0; i < n; ++i) {
        if ((combo >> i) & 1)
            cout << c[i] << ' ';
    }
    cout << endl;
}

template<typename T>
void combo(const T& c, int k)
{
    int n = c.size();
    int combo = (1 << k) - 1;       // k bit sets
    while (combo < 1<<n) {

        pretty_print(c, combo);

        int x = combo & -combo;
        int y = combo + x;
        int z = (combo & ~y);
        combo = z / x;
        combo >>= 1;
        combo |= y;
    }
}

int main()
{
    vector<char> c0 = {'1', '2', '3', '4', '5'};
    combo(c0, 3);

    vector<char> c1 = {'a', 'b', 'c', 'd', 'e', 'f', 'g'};
    combo(c1, 4);
    return 0;
}

result :

1 2 3 
1 2 4 
1 3 4 
2 3 4 
1 2 5 
1 3 5 
2 3 5 
1 4 5 
2 4 5 
3 4 5 
a b c d 
a b c e 
a b d e 
a c d e 
b c d e 
a b c f 
a b d f 
a c d f 
b c d f 
a b e f 
a c e f 
b c e f 
a d e f 
b d e f 
c d e f 
a b c g 
a b d g 
a c d g 
b c d g 
a b e g 
a c e g 
b c e g 
a d e g 
b d e g 
c d e g 
a b f g 
a c f g 
b c f g 
a d f g 
b d f g 
c d f g 
a e f g 
b e f g 
c e f g 
d e f g 

Ruby 'require' error: cannot load such file

Another nice little method is to include the current directory in your load path with

$:.unshift('.')

You could push it onto the $: ($LOAD_PATH) array but unshift will force it to load your current working directory before the rest of the load path.

Once you've added your current directory in your load path you don't need to keep specifying

 require './tokenizer' 

and can just go back to using

require 'tokenizer'

How to set editor theme in IntelliJ Idea

OK I found the problem, I was checking in the wrong place which is for the whole IDE's look and feel at File->Settings->Appearance

The correct place to change the editor appearance is through File->Settings->Editor->Colors &Fonts and then choose the scheme there. The imported settings appear there :)

Note: The theme site seems to have moved.

How to get datetime in JavaScript?

try this:

_x000D_
_x000D_
var today = new Date();
var date = today.getFullYear()+'-'+(today.getMonth()+1)+'-'+today.getDate();
var time = today.getHours()+':'+today.getMinutes()+':'+today.getSeconds();
console.log(date + ' '+ time);
_x000D_
_x000D_
_x000D_

Difference between binary tree and binary search tree

Binary tree: Tree where each node has up to two leaves

  1
 / \
2   3

Binary search tree: Used for searching. A binary tree where the left child contains only nodes with values less than the parent node, and where the right child only contains nodes with values greater than or equal to the parent.

  2
 / \
1   3

Adding local .aar files to Gradle build using "flatDirs" is not working

If you already use Kotlin Gradle DSL, the alternative to using it this way:

Here's my project structure

|-root
|----- app
|--------- libs // I choose to store the aar here
|-------------- my-libs-01.aar
|-------------- my-libs-02.jar
|--------- build.gradle.kts // app module gradle
|----- common-libs // another aar folder/directory
|----------------- common-libs-01.aar
|----------------- common-libs-02.jar
|----- build.gradle.kts // root gradle

My app/build.gradle.kts

  1. Using simple approach with fileTree
// android related config above omitted...

dependencies {
    // you can do this to include everything in the both directory
    // Inside ./root/common-libs & ./root/app/libs
    implementation(fileTree(mapOf("dir" to "libs", "include" to listOf("*.jar", "*.aar"))))
    implementation(fileTree(mapOf("dir" to "../common-libs", "include" to listOf("*.jar", "*.aar"))))
}
  1. Using same approach like fetching from local / remote maven repository with flatDirs
// android related config above omitted...

repositories {
    flatDir {
        dirs = mutableSetOf(File("libs"), File("../common-libs") 
    }
}

dependencies {
   implementation(group = "", name = "my-libs-01", ext = "aar")
   implementation(group = "", name = "my-libs-02", ext = "jar")

   implementation(group = "", name = "common-libs-01", ext = "aar")
   implementation(group = "", name = "common-libs-02", ext = "jar")
}

The group was needed, due to its mandatory (not optional/has default value) in kotlin implementation, see below:

// Filename: ReleaseImplementationConfigurationAccessors.kt
package org.gradle.kotlin.dsl

fun DependencyHandler.`releaseImplementation`(
    group: String,
    name: String,
    version: String? = null,
    configuration: String? = null,
    classifier: String? = null,
    ext: String? = null,
    dependencyConfiguration: Action<ExternalModuleDependency>? = null
)

Disclaimer: The difference using no.1 & flatDirs no.2 approach, I still don't know much, you might want to edit/comment to this answer.

References:

  1. https://stackoverflow.com/a/56828958/3763032
  2. https://github.com/gradle/gradle/issues/9272

How to select following sibling/xml tag using xpath

Try the following-sibling axis (following-sibling::td).

"Expected BEGIN_OBJECT but was STRING at line 1 column 1"

I have come to share an solution. The error happened to me after forcing the notbook to hang up. possible solution clean preject.

MySQL Nested Select Query?

You just need to write the first query as a subquery (derived table), inside parentheses, pick an alias for it (t below) and alias the columns as well.

The DISTINCT can also be safely removed as the internal GROUP BY makes it redundant:

SELECT DATE(`date`) AS `date` , COUNT(`player_name`) AS `player_count`
FROM (
    SELECT MIN(`date`) AS `date`, `player_name`
    FROM `player_playtime`
    GROUP BY `player_name`
) AS t
GROUP BY DATE( `date`) DESC LIMIT 60 ;

Since the COUNT is now obvious that is only counting rows of the derived table, you can replace it with COUNT(*) and further simplify the query:

SELECT t.date , COUNT(*) AS player_count
FROM (
    SELECT DATE(MIN(`date`)) AS date
    FROM player_playtime
    GROUP BY player_name
) AS t
GROUP BY t.date DESC LIMIT 60 ;

How do I make a LinearLayout scrollable?

Put your whole content in linear layout which is placed inside ScrollView.

ScrollView takes only one layout as its child.

isScrollContainer="true"

This property is used when your softkey in android pops up and still you want your view to scroll.

JWT (Json Web Token) Audience "aud" versus Client_Id - What's the difference?

Though this is old, I think question is valid even today

My suspicion is that aud should refer to the resource server(s), and the client_id should refer to one of the client applications recognized by the authentication server

Yes, aud should refer to token consuming party. And client_id refers to token obtaining party.

In my current case, my resource server is also my web app client.

In the OP's scenario, web app and resource server both belongs to same party. So this means client and audience to be same. But there can be situations where this is not the case.

Think about a SPA which consume an OAuth protected resource. In this scenario SPA is the client. Protected resource is the audience of access token.

This second scenario is interesting. There is a working draft in place named "Resource Indicators for OAuth 2.0" which explain where you can define the intended audience in your authorisation request. So the resulting token will restricted to the specified audience. Also, Azure OIDC use a similar approach where it allows resource registration and allow auth request to contain resource parameter to define access token intended audience. Such mechanisms allow OAuth adpotations to have a separation between client and token consuming (audience) party.

JPanel vs JFrame in Java

You should not extend the JFrame class unnecessarily (only if you are adding extra functionality to the JFrame class)

JFrame:

JFrame extends Component and Container.

It is a top level container used to represent the minimum requirements for a window. This includes Borders, resizability (is the JFrame resizeable?), title bar, controls (minimize/maximize allowed?), and event handlers for various Events like windowClose, windowOpened etc.

JPanel:

JPanel extends Component, Container and JComponent

It is a generic class used to group other Components together.

  • It is useful when working with LayoutManagers e.g. GridLayout f.i adding components to different JPanels which will then be added to the JFrame to create the gui. It will be more manageable in terms of Layout and re-usability.

  • It is also useful for when painting/drawing in Swing, you would override paintComponent(..) and of course have the full joys of double buffering.

A Swing GUI cannot exist without a top level container like (JWindow, Window, JFrame Frame or Applet), while it may exist without JPanels.

Attribute 'nowrap' is considered outdated. A newer construct is recommended. What is it?

If HTML and use bootstrap they have a helper class.

<span class="text-nowrap">1-866-566-7233</span>

How to add pandas data to an existing csv file?

A little helper function I use with some header checking safeguards to handle it all:

def appendDFToCSV_void(df, csvFilePath, sep=","):
    import os
    if not os.path.isfile(csvFilePath):
        df.to_csv(csvFilePath, mode='a', index=False, sep=sep)
    elif len(df.columns) != len(pd.read_csv(csvFilePath, nrows=1, sep=sep).columns):
        raise Exception("Columns do not match!! Dataframe has " + str(len(df.columns)) + " columns. CSV file has " + str(len(pd.read_csv(csvFilePath, nrows=1, sep=sep).columns)) + " columns.")
    elif not (df.columns == pd.read_csv(csvFilePath, nrows=1, sep=sep).columns).all():
        raise Exception("Columns and column order of dataframe and csv file do not match!!")
    else:
        df.to_csv(csvFilePath, mode='a', index=False, sep=sep, header=False)

Chrome sendrequest error: TypeError: Converting circular structure to JSON

I have experienced the same error when trying to build the message below with jQuery. The circular reference happens when reviewerName was being mistakenly assigned to msg.detail.reviewerName. JQuery's .val() fixed the issue, see last line.

var reviewerName = $('reviewerName'); // <input type="text" id="taskName" />;
var msg = {"type":"A", "detail":{"managerReview":true} };
msg.detail.reviewerName = reviewerName; // Error
msg.detail.reviewerName = reviewerName.val(); // Fixed

How to convert decimal to hexadecimal in JavaScript

Constrained/padded to a set number of characters:

function decimalToHex(decimal, chars) {
    return (decimal + Math.pow(16, chars)).toString(16).slice(-chars).toUpperCase();
}

How do I display a decimal value to 2 decimal places?

https://msdn.microsoft.com/en-us/library/dwhawy9k%28v=vs.110%29.aspx

This link explains in detail how you can handle your problem and what you can do if you want to learn more. For simplicity purposes, what you want to do is

double whateverYouWantToChange = whateverYouWantToChange.ToString("F2");

if you want this for a currency, you can make it easier by typing "C2" instead of "F2"

Shell Script — Get all files modified after <date>

I would simply do the following to backup all new files from 7 days ago

tar --newer $(date -d'7 days ago' +"%d-%b") -zcf thisweek.tgz .

note you can also replace '7 days ago' with anything that suits your need

Can be : date -d'yesterday' +"%d-%b"

Or even : date -d'first Sunday last month' +"%d-%b"

Check if an array item is set in JS

function isset(key){
ret = false;
array_example.forEach(function(entry) {
  if( entry == key ){
    ret = true;
  }
});
return ret;
}

alert( isset("key_search") );

How do I trigger a macro to run after a new mail is received in Outlook?

Try something like this inside ThisOutlookSession:

Private Sub Application_NewMail()
    Call Your_main_macro
End Sub

My outlook vba just fired when I received an email and had that application event open.

Edit: I just tested a hello world msg box and it ran after being called in the application_newmail event when an email was received.

linux/videodev.h : no such file or directory - OpenCV on ubuntu 11.04

v4l support has been dropped in recent kernel versions (including the one shipped with Ubuntu 11.04).

EDIT: Your question is connected to a recent message that was sent to the OpenCV users group, which has instructions to compile OpenCV 2.2 in Ubuntu 11.04. Your approach is not ideal.

Cant get text of a DropDownList in code - can get value but not text

AppendDataBoundItems="true" needs to be set.

How do I generate sourcemaps when using babel and webpack?

Maybe someone else has this problem at one point. If you use the UglifyJsPlugin in webpack 2 you need to explicitly specify the sourceMap flag. For example:

new webpack.optimize.UglifyJsPlugin({ sourceMap: true })

See last changes in svn

svn log -r {2009-09-17}:HEAD

where 2009-09-17 is the date you went on holiday. To see the changed files as well as the summary, add a -v option:

svn log -r {2009-09-17}:HEAD -v

I haven't used WebSVN but there will be a log viewer somewhere that does the equivalent of these commands under the hood.

indexOf method in an object array?

In ES2015, this is pretty easy:

myArray.map(x => x.hello).indexOf('stevie')

or, probably with better performance for larger arrays:

myArray.findIndex(x => x.hello === 'stevie')

How to determine a Python variable's type?

One more way using __class__:

>>> a = [1, 2, 3, 4]
>>> a.__class__
<type 'list'>
>>> b = {'key1': 'val1'}
>>> b.__class__
<type 'dict'>
>>> c = 12
>>> c.__class__
<type 'int'>

Could not open ServletContext resource

I had the same error.

My filename was jpaContext.xml and it was placed in src/main/resources. I specified param value="classpath:/jpaContext.xml".

Finally I renamed the file to applicationContext.xml and moved it to the WEB-INF directory and changed param value to /WEB-INF/applicationContext.xml, then it worked!

Instagram how to get my user id from username?

Currently there is no direct Instagram API to get user id from user name. You need to call the GET /users/search API and then iterate the results and check if the username field value is equal to your username or not, then you grab the id.

Multi-dimensional associative arrays in JavaScript

    var myObj = [];
    myObj['Base'] = [];
    myObj['Base']['Base.panel.panel_base'] = {ContextParent:'',ClassParent:'',NameParent:'',Context:'Base',Class:'panel',Name:'panel_base',Visible:'',ValueIst:'',ValueSoll:'',
                                              Align:'',  AlignFrom:'',AlignTo:'',Content:'',onClick:'',Style:'',content_ger_sie:'',content_ger_du:'',content_eng:'' };
    myObj['Base']['Base.panel.panel_top']  = {ContextParent:'',ClassParent:'',NameParent:'',Context:'Base',Class:'panel',Name:'panel_base',Visible:'',ValueIst:'',ValueSoll:'',
                                              Align:'',AlignFrom:'',AlignTo:'',Content:'',onClick:'',Style:'',content_ger_sie:'',content_ger_du:'',content_eng:'' };

    myObj['SC1'] = [];
    myObj['SC1']['Base.panel.panel_base'] = {ContextParent:'',ClassParent:'',NameParent:'',Context:'Base',Class:'panel',Name:'panel_base',Visible:'',ValueIst:'',ValueSoll:'',
                                              Align:'',  AlignFrom:'',AlignTo:'',Content:'',onClick:'',Style:'',content_ger_sie:'',content_ger_du:'',content_eng:'' };
    myObj['SC1']['Base.panel.panel_top']  = {ContextParent:'',ClassParent:'',NameParent:'',Context:'Base',Class:'panel',Name:'panel_base',Visible:'',ValueIst:'',ValueSoll:'',
                                              Align:'',AlignFrom:'',AlignTo:'',Content:'',onClick:'',Style:'',content_ger_sie:'',content_ger_du:'',content_eng:'' };


    console.log(myObj);

    if ('Base' in myObj) {
      console.log('Base found');

      if ('Base.panel.panel_base' in myObj['Base'])  {
        console.log('Base.panel.panel_base found'); 


      console.log('old value: ' + myObj['Base']['Base.panel.panel_base'].Context);  
      myObj['Base']['Base.panel.panel_base'] = 'new Value';
      console.log('new value: ' + myObj['Base']['Base.panel.panel_base']);
      }
    }

Output:

  • Base found
  • Base.panel.panel_base found
  • old value: Base
  • new value: new Value

The array operation works. There is no problem.

Iteration:

     Object.keys(myObj['Base']).forEach(function(key, index) {            
        var value = objcons['Base'][key];                   
      }, myObj);

How can one use multi threading in PHP applications

If you are using a Linux server, you can use

exec("nohup $php_path path/script.php > /dev/null 2>/dev/null &")

If you need pass some args

exec("nohup $php_path path/script.php $args > /dev/null 2>/dev/null &")

In script.php

$args = $argv[1];

Or use Symfony https://symfony.com/doc/current/components/process.html

$process = Process::fromShellCommandline("php ".base_path('script.php'));
$process->setTimeout(0);     
$process->disableOutput();     
$process->start();

Function Pointers in Java

This brings to mind Steve Yegge's Execution in the Kingdom of Nouns. It basically states that Java needs an object for every action, and therefore does not have "verb-only" entities like function pointers.

How to show the "Are you sure you want to navigate away from this page?" when changes committed?

Here try this it works 100%

<html>
<body>
<script>
var warning = true;
window.onbeforeunload = function() {  
  if (warning) {  
    return "You have made changes on this page that you have not yet confirmed. If you navigate away from this page you will lose your unsaved changes";  
    }  
}

$('form').submit(function() {
   window.onbeforeunload = null;
});
</script>
</body>
</html>

Is it possible to change javascript variable values while debugging in Google Chrome?

I don't know why chrome team don't allow this silly feature ... but the only way I could change variable values with success is to modify the script directly in the chrome editor under "Sources" Tab (this changes the behavior of your script until you refresh the page), but that changes will lost when refresh, so be carefull.

Saving any file to in the database, just convert it to a byte array?

While you can store files in this fashion, it has significant tradeoffs:

  • Most DBs are not optimized for giant quantities of binary data, and query performance often degrades dramatically as the table bloats, even with indexes. (SQL Server 2008, with the FILESTREAM column type, is the exception to the rule.)
  • DB backup/replication becomes extremely slow.
  • It's a lot easier to handle a corrupted drive with 2 million images -- just replace the disk on the RAID -- than a DB table that becomes corrupted.
  • If you accidentally delete a dozen images on a filesystem, your operations guys can replace them pretty easily from a backup, and since the table index is tiny by comparison, it can be restored quickly. If you accidentally delete a dozen images in a giant database table, you have a long and painful wait to restore the DB from backup, paralyzing your entire system in the meantime.

These are just some of the drawbacks I can come up with off the top of my head. For tiny projects it may be worth storing files in this fashion, but if you're designing enterprise-grade software I would strongly recommend against it.

How do you round a double in Dart to a given degree of precision AFTER the decimal point?

I think the accepted answer is not the perfect solution because it converts to string.

If you don't wanna convert to string and back to a double use double.toPrecision(decimalNumber) from GetX package.

If you don't wanna use GetX just for this (I highly recommend GetX, it will change your life with flutter) you can copy and paste this.

import 'dart:math';

extension Precision on double {
  double toPrecision(int fractionDigits) {
    var mod = pow(10, fractionDigits.toDouble()).toDouble();
    return ((this * mod).round().toDouble() / mod);
  }
}

Automatically resize images with browser size using CSS

This may be too simplistic of an answer (I am still new here), but what I have done in the past to remedy this situation is figured out the percentage of the screen I would like the image to take up. For example, there is one webpage I am working on where the logo must take up 30% of the screen size to look best. I played around and finally tried this code and it has worked for me thus far:

img {
width:30%;
height:auto;
}

That being said, this will change all of your images to be 30% of the screen size at all times. To get around this issue, simply make this a class and apply it to the image that you desire to be at 30% directly. Here is an example of the code I wrote to accomplish this on the aforementioned site:

the CSS portion:

.logo {
position:absolute;
right:25%;
top:0px;
width:30%;
height:auto;
}

the HTML portion:

<img src="logo_001_002.png" class="logo">

Alternatively, you could place ever image you hope to automatically resize into a div of its own and use the class tag option on each div (creating now class tags whenever needed), but I feel like that would cause a lot of extra work eventually. But, if the site calls for it: the site calls for it.

Hopefully this helps. Have a great day!

How do I add an element to a list in Groovy?

From the documentation:

We can add to a list in many ways:

assert [1,2] + 3 + [4,5] + 6 == [1, 2, 3, 4, 5, 6]
assert [1,2].plus(3).plus([4,5]).plus(6) == [1, 2, 3, 4, 5, 6]
    //equivalent method for +
def a= [1,2,3]; a += 4; a += [5,6]; assert a == [1,2,3,4,5,6]
assert [1, *[222, 333], 456] == [1, 222, 333, 456]
assert [ *[1,2,3] ] == [1,2,3]
assert [ 1, [2,3,[4,5],6], 7, [8,9] ].flatten() == [1, 2, 3, 4, 5, 6, 7, 8, 9]

def list= [1,2]
list.add(3) //alternative method name
list.addAll([5,4]) //alternative method name
assert list == [1,2,3,5,4]

list= [1,2]
list.add(1,3) //add 3 just before index 1
assert list == [1,3,2]
list.addAll(2,[5,4]) //add [5,4] just before index 2
assert list == [1,3,5,4,2]

list = ['a', 'b', 'z', 'e', 'u', 'v', 'g']
list[8] = 'x'
assert list == ['a', 'b', 'z', 'e', 'u', 'v', 'g', null, 'x']

You can also do:

def myNewList = myList << "fifth"

ORA-28040: No matching authentication protocol exception

Here is some text I found at experts-exchange:

Bug 14575666

In 12.1, the default value for the SQLNET.ALLOWED_LOGON_VERSION parameter has been updated to 11. This means that database clients using pre-11g JDBC thin drivers cannot authenticate to 12.1 database servers unless theSQLNET.ALLOWED_LOGON_VERSION parameter is set to the old default of 8.

This will cause a 10.2.0.5 Oracle RAC database creation using DBCA to fail with the ORA-28040: No matching authentication protocol error in 12.1 Oracle ASM and Oracle Grid Infrastructure environments.

Workaround: Set SQLNET.ALLOWED_LOGON_VERSION=8 in the oracle/network/admin/sqlnet.ora file.

How to get an absolute file path in Python

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

To get an absolute path in Windows:

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

Or on UNIX:

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

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

Draw an X in CSS

Check & and Cross:

<span class='act-html-check'></span>
<span class='act-html-cross'><span class='act-html-cross'></span></span>

<style type="text/css">
span.act-html-check {
                display: inline-block;
                width: 12px;
                height: 18px;
                border: solid limegreen;
                border-width: 0 5px 5px 0;
                transform: rotate( 45deg);
            }


            span.act-html-cross {
                display: inline-block;
                width: 10px;
                height: 10px;
                border: solid red;
                border-width: 0 5px 5px 0;
                transform: rotate( 45deg);
                position: relative;
            }

            span.act-html-cross > span { {
                transform: rotate( -180deg);
                position: absolute;
                left: 9px;
                top: 9px;
            }
</style>

Delete/Reset all entries in Core Data?

You can still delete the file programmatically, using the NSFileManager:removeItemAtPath:: method.

NSPersistentStore *store = ...;
NSError *error;
NSURL *storeURL = store.URL;
NSPersistentStoreCoordinator *storeCoordinator = ...;
[storeCoordinator removePersistentStore:store error:&error];
[[NSFileManager defaultManager] removeItemAtPath:storeURL.path error:&error];

Then, just add the persistent store back to ensure it is recreated properly.

The programmatic way for iterating through each entity is both slower and prone to error. The use for doing it that way is if you want to delete some entities and not others. However you still need to make sure you retain referential integrity or you won't be able to persist your changes.

Just removing the store and recreating it is both fast and safe, and can certainly be done programatically at runtime.

Update for iOS5+

With the introduction of external binary storage (allowsExternalBinaryDataStorage or Store in External Record File) in iOS 5 and OS X 10.7, simply deleting files pointed by storeURLs is not enough. You'll leave the external record files behind. Since the naming scheme of these external record files is not public, I don't have a universal solution yet. – an0 May 8 '12 at 23:00

Getting command-line password input in Python

15.7. getpass — Portable password input

#!/usr/bin/python3
from getpass import getpass
passwd = getpass("password: ")
print(passwd)

You can read more here

Python Remove last 3 characters of a string

  1. split
  2. slice
  3. concentrate

This is a good workout for beginners and it's easy to achieve.

Another advanced method is a function like this:

def trim(s):
    return trim(s[slice])

And for this question, you just want to remove the last characters, so you can write like this:

def trim(s):
    return s[ : -3] 

I think you are over to care about what those three characters are, so you lost. You just want to remove last three, nevertheless who they are!

If you want to remove some specific characters, you can add some if judgements:

def trim(s):
    if [conditions]:   ### for some cases, I recommend using isinstance().
        return trim(s[slice])

How to Disable landscape mode in Android?

I was not aware of the AndroidManifest.xml file switch until reading this post, so in my apps I have used this instead:

setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);     //  Fixed Portrait orientation

onNewIntent() lifecycle and registered listeners

Note: Calling a lifecycle method from another one is not a good practice. In below example I tried to achieve that your onNewIntent will be always called irrespective of your Activity type.

OnNewIntent() always get called for singleTop/Task activities except for the first time when activity is created. At that time onCreate is called providing to solution for few queries asked on this thread.

You can invoke onNewIntent always by putting it into onCreate method like

@Override
public void onCreate(Bundle savedState){
    super.onCreate(savedState);
    onNewIntent(getIntent());
}

@Override
protected void onNewIntent(Intent intent) {
  super.onNewIntent(intent);
  //code
}

How do I calculate a point on a circle’s circumference?

Implemented in JavaScript (ES6):

/**
    * Calculate x and y in circle's circumference
    * @param {Object} input - The input parameters
    * @param {number} input.radius - The circle's radius
    * @param {number} input.angle - The angle in degrees
    * @param {number} input.cx - The circle's origin x
    * @param {number} input.cy - The circle's origin y
    * @returns {Array[number,number]} The calculated x and y
*/
function pointsOnCircle({ radius, angle, cx, cy }){

    angle = angle * ( Math.PI / 180 ); // Convert from Degrees to Radians
    const x = cx + radius * Math.sin(angle);
    const y = cy + radius * Math.cos(angle);
    return [ x, y ];

}

Usage:

const [ x, y ] = pointsOnCircle({ radius: 100, angle: 180, cx: 150, cy: 150 });
console.log( x, y );

Codepen

_x000D_
_x000D_
/**
 * Calculate x and y in circle's circumference
 * @param {Object} input - The input parameters
 * @param {number} input.radius - The circle's radius
 * @param {number} input.angle - The angle in degrees
 * @param {number} input.cx - The circle's origin x
 * @param {number} input.cy - The circle's origin y
 * @returns {Array[number,number]} The calculated x and y
 */
function pointsOnCircle({ radius, angle, cx, cy }){
  angle = angle * ( Math.PI / 180 ); // Convert from Degrees to Radians
  const x = cx + radius * Math.sin(angle);
  const y = cy + radius * Math.cos(angle);
  return [ x, y ];
}

const canvas = document.querySelector("canvas");
const ctx = canvas.getContext("2d");

function draw( x, y ){

  ctx.clearRect( 0, 0, canvas.width, canvas.height );
  ctx.beginPath();
  ctx.strokeStyle = "orange";
  ctx.arc( 100, 100, 80, 0, 2 * Math.PI);
  ctx.lineWidth = 3;
  ctx.stroke();
  ctx.closePath();

  ctx.beginPath();
  ctx.fillStyle = "indigo";
  ctx.arc( x, y, 6, 0, 2 * Math.PI);
  ctx.fill();
  ctx.closePath();
  
}

let angle = 0;  // In degrees
setInterval(function(){

  const [ x, y ] = pointsOnCircle({ radius: 80, angle: angle++, cx: 100, cy: 100 });
  console.log( x, y );
  draw( x, y );
  document.querySelector("#degrees").innerHTML = angle + "&deg;";
  document.querySelector("#points").textContent = x.toFixed() + "," + y.toFixed();

}, 100 );
_x000D_
<p>Degrees: <span id="degrees">0</span></p>
<p>Points on Circle (x,y): <span id="points">0,0</span></p>
<canvas width="200" height="200" style="border: 1px solid"></canvas>
_x000D_
_x000D_
_x000D_

How to log out user from web site using BASIC authentication?

_x000D_
_x000D_
    function logout(secUrl, redirUrl) {_x000D_
        if (bowser.msie) {_x000D_
            document.execCommand('ClearAuthenticationCache', 'false');_x000D_
        } else if (bowser.gecko) {_x000D_
            $.ajax({_x000D_
                async: false,_x000D_
                url: secUrl,_x000D_
                type: 'GET',_x000D_
                username: 'logout'_x000D_
            });_x000D_
        } else if (bowser.webkit) {_x000D_
            var xmlhttp = new XMLHttpRequest();_x000D_
            xmlhttp.open("GET", secUrl, true);_x000D_
            xmlhttp.setRequestHeader("Authorization", "Basic logout");_x000D_
            xmlhttp.send();_x000D_
        } else {_x000D_
            alert("Logging out automatically is unsupported for " + bowser.name_x000D_
                + "\nYou must close the browser to log out.");_x000D_
        }_x000D_
        setTimeout(function () {_x000D_
            window.location.href = redirUrl;_x000D_
        }, 200);_x000D_
    }
_x000D_
_x000D_
_x000D_

I tried using the above in the following way.

?php
    ob_start();
    session_start();
    require_once 'dbconnect.php';

    // if session is not set this will redirect to login page
    if( !isset($_SESSION['user']) ) {
        header("Location: index.php");
        exit;
    }
    // select loggedin users detail
    $res=mysql_query("SELECT * FROM users WHERE userId=".$_SESSION['user']);
    $userRow=mysql_fetch_array($res);
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Welcome - <?php echo $userRow['userEmail']; ?></title>
<link rel="stylesheet" href="assets/css/bootstrap.min.css" type="text/css"  />
<link rel="stylesheet" href="style.css" type="text/css" />

    <script src="assets/js/bowser.min.js"></script>
<script>
//function logout(secUrl, redirUrl)
//bowser = require('bowser');
function logout(secUrl, redirUrl) {
alert(redirUrl);
    if (bowser.msie) {
        document.execCommand('ClearAuthenticationCache', 'false');
    } else if (bowser.gecko) {
        $.ajax({
            async: false,
            url: secUrl,
            type: 'GET',
            username: 'logout'
        });
    } else if (bowser.webkit) {
        var xmlhttp = new XMLHttpRequest();
        xmlhttp.open("GET", secUrl, true);
        xmlhttp.setRequestHeader("Authorization", "Basic logout");
        xmlhttp.send();
    } else {
        alert("Logging out automatically is unsupported for " + bowser.name
            + "\nYou must close the browser to log out.");
    }
    window.location.assign(redirUrl);
    /*setTimeout(function () {
        window.location.href = redirUrl;
    }, 200);*/
}


function f1()
    {
       alert("f1 called");
       //form validation that recalls the page showing with supplied inputs.    
    }
</script>
</head>
<body>

    <nav class="navbar navbar-default navbar-fixed-top">
      <div class="container">
        <div class="navbar-header">
          <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
            <span class="sr-only">Toggle navigation</span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
          </button>
          <a class="navbar-brand" href="http://www.codingcage.com">Coding Cage</a>
        </div>
        <div id="navbar" class="navbar-collapse collapse">
          <ul class="nav navbar-nav">
            <li class="active"><a href="http://www.codingcage.com/2015/01/user-registration-and-login-script-using-php-mysql.html">Back to Article</a></li>
            <li><a href="http://www.codingcage.com/search/label/jQuery">jQuery</a></li>
            <li><a href="http://www.codingcage.com/search/label/PHP">PHP</a></li>
          </ul>
          <ul class="nav navbar-nav navbar-right">

            <li class="dropdown">
              <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">
              <span class="glyphicon glyphicon-user"></span>&nbsp;Hi' <?php echo $userRow['userEmail']; ?>&nbsp;<span class="caret"></span></a>
              <ul class="dropdown-menu">
                <li><a href="logout.php?logout"><span class="glyphicon glyphicon-log-out"></span>&nbsp;Sign Out</a></li>
              </ul>
            </li>
          </ul>
        </div><!--/.nav-collapse -->
      </div>
    </nav> 

    <div id="wrapper">

    <div class="container">

        <div class="page-header">
        <h3>Coding Cage - Programming Blog</h3>
        </div>

        <div class="row">
        <div class="col-lg-12" id="div_logout">
        <h1 onclick="logout(window.location.href, 'www.espncricinfo.com')">MichaelA1S1! Click here to see log out functionality upon click inside div</h1>
        </div>
        </div>

    </div>

    </div>

    <script src="assets/jquery-1.11.3-jquery.min.js"></script>
    <script src="assets/js/bootstrap.min.js"></script>


</body>
</html>
<?php ob_end_flush(); ?>

But it only redirects you to new location. No logout.

How to add elements of a string array to a string array list?

Use asList() method. From java Doc asList

List<String> species = Arrays.asList(speciesArr);

Python: Pandas pd.read_excel giving ImportError: Install xlrd >= 0.9.0 for Excel support

Since December 2020 xlrd no longer supports xlsx-Files as explained in the official changelog. You can use openpyxl instead:

pip install openpyxl

And in your python-file:

import pandas as pd
pd.read_excel('path/to/file.xlsx', engine='openpyxl')

Send email using java

Here is the working solution bro. It's guranteed.

  1. First of all open your gmail account from which you wanted to send mail, like in you case [email protected]
  2. Open this link below:

    https://support.google.com/accounts/answer/6010255?hl=en

  3. Click on "Go to the "Less secure apps" section in My Account." option
  4. Then turn on it
  5. That's it (:

Here is my code:

import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;

public class SendEmail {

   final String senderEmailID = "Sender Email id";
final String senderPassword = "Sender Pass word";
final String emailSMTPserver = "smtp.gmail.com";
final String emailServerPort = "465";
String receiverEmailID = null;
static String emailSubject = "Test Mail";
static String emailBody = ":)";
public SendEmail(String receiverEmailID, String emailSubject, String emailBody)
{
this.receiverEmailID=receiverEmailID;
this.emailSubject=emailSubject;
this.emailBody=emailBody;
Properties props = new Properties();
props.put("mail.smtp.user",senderEmailID);
props.put("mail.smtp.host", emailSMTPserver);
props.put("mail.smtp.port", emailServerPort);
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.socketFactory.port", emailServerPort);
props.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.fallback", "false");
SecurityManager security = System.getSecurityManager();
try
{
Authenticator auth = new SMTPAuthenticator();
Session session = Session.getInstance(props, auth);
MimeMessage msg = new MimeMessage(session);
msg.setText(emailBody);
msg.setSubject(emailSubject);
msg.setFrom(new InternetAddress(senderEmailID));
msg.addRecipient(Message.RecipientType.TO,
new InternetAddress(receiverEmailID));
Transport.send(msg);
System.out.println("Message send Successfully:)");
}
catch (Exception mex)
{
mex.printStackTrace();
}
}
public class SMTPAuthenticator extends javax.mail.Authenticator
{
public PasswordAuthentication getPasswordAuthentication()
{
return new PasswordAuthentication(senderEmailID, senderPassword);
}
}
    public static void main(String[] args) {
       SendEmail mailSender;
        mailSender = new SendEmail("Receiver Email id","Testing Code 2 example","Testing Code Body yess");
    }

}

Switching from zsh to bash on OSX, and back again?

you can try chsh -s /bin/bash to set the bash as the default, or chsh -s /bin/zsh to set the zsh as the default.

Terminal will need a restart to take effect.

How to return JSON with ASP.NET & jQuery

This structure works for me - I used it in a small tasks management application.

The controller:

public JsonResult taskCount(string fDate)
{
  // do some stuff based on the date

  // totalTasks is a count of the things I need to do today
  // tasksDone is a count of the tasks I actually did
  // pcDone is the percentage of tasks done

  return Json(new {
    totalTasks = totalTasks,
    tasksDone = tasksDone,
    percentDone = pcDone
  });
}

In the AJAX call I access the data like this:

.done(function (data) {
  // data.totalTasks
  // data.tasksDone
  // data.percentDone
});

Array versus List<T>: When to use which?

Arrays Vs. Lists is a classic maintainability vs. performance problem. The rule of thumb that nearly all developers follow is that you should shoot for both, but when they come in to conflict, choose maintainability over performance. The exception to that rule is when performance has already proven to be an issue. If you carry this principle in to Arrays Vs. Lists, then what you get is this:

Use strongly typed lists until you hit performance problems. If you hit a performance problem, make a decision as to whether dropping out to arrays will benefit your solution with performance more than it will be a detriment to your solution in terms of maintenance.

Comparing two input values in a form validation with AngularJS

One way to achieve this is with a custom directive. Here's an example using a custom directive (ng-match in this case):

<p>Email:<input type="email" name="email1" ng-model="emailReg">
Repeat Email:<input type="email" name="email2" ng-model="emailReg2" ng-match="emailReg"></p>

<span data-ng-show="myForm.emailReg2.$error.match">Emails have to match!</span>

NOTE: It's not generally recommended to use ng- as a prefix for a custom directive because it may conflict with an official AngularJS directive.

Update

It's also possible to get this functionality without using a custom directive:

HTML

<button ng-click="add()></button>
<span ng-show="IsMatch">Emails have to match!</span>

Controller

$scope.add = function() {
  if ($scope.emailReg != $scope.emailReg2) {
    $scope.IsMatch=true;
    return false;
  }
  $scope.IsMatch=false;
}

How to encode Doctrine entities to JSON in Symfony 2.0 AJAX application?

I just had to solve the same problem: json-encoding an entity ("User") having a One-To-Many Bidirectional Association to another Entity ("Location").

I tried several things and I think now I found the best acceptable solution. The idea was to use the same code as written by David, but somehow intercept the infinite recursion by telling the Normalizer to stop at some point.

I did not want to implement a custom normalizer, as this GetSetMethodNormalizer is a nice approach in my opinion (based on reflection etc.). So I've decided to subclass it, which is not trivial at first sight, because the method to say if to include a property (isGetMethod) is private.

But, one could override the normalize method, so I intercepted at this point, by simply unsetting the property that references "Location" - so the inifinite loop is interrupted.

In code it looks like this:

class GetSetMethodNormalizer extends \Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer {

    public function normalize($object, $format = null)
    {
        // if the object is a User, unset location for normalization, without touching the original object
        if($object instanceof \Leonex\MoveBundle\Entity\User) {
            $object = clone $object;
            $object->setLocations(new \Doctrine\Common\Collections\ArrayCollection());
        }

        return parent::normalize($object, $format);
    }

} 

Error: "an object reference is required for the non-static field, method or property..."

Simply add static in the declaration of these two methods and the compile time error will disappear!

By default in C# methods are instance methods, and they receive the implicit "self" argument. By making them static, no such argument is needed (nor available), and the method must then of course refrain from accessing any instance (non-static) objects or methods of the class.

More info on static methods
Provided the class and the method's access modifiers (public vs. private) are ok, a static method can then be called from anywhere without having to previously instantiate a instance of the class. In other words static methods are used with the following syntax:

    className.classMethod(arguments)
rather than
    someInstanceVariable.classMethod(arguments)

A classical example of static methods are found in the System.Math class, whereby we can call a bunch of these methods like

   Math.Sqrt(2)
   Math.Cos(Math.PI)

without ever instantiating a "Math" class (in fact I don't even know if such an instance is possible)

Adding a public key to ~/.ssh/authorized_keys does not log me in automatically

I have the home directory in a non-standard location and in sshd logs I have the following line, even if all permissions were just fine (see the other answers):

Could not open authorized keys '/data/home/user1/.ssh/authorized_keys': Permission denied

I have found a solution here: Trouble with ssh public key authentication to RHEL 6.5

In my particular case:

  • Added a new line in /etc/selinux/targeted/contexts/files/file_contexts.homedirs:

  • This is the original line for regular home directories:

    /home/[^/]*/\.ssh(/.*)? unconfined_u:object_r:ssh_home_t:s0

  • This is my new line:

    /data/home/[^/]*/\.ssh(/.*)? unconfined_u:object_r:ssh_home_t:s0

  • Followed by a restorecon -r /data/ and a sshd restart.

What exactly does big ? notation represent?

Theta(n): A function f(n) belongs to Theta(g(n)), if there exists positive constants c1 and c2 such that f(n) can be sandwiched between c1(g(n)) and c2(g(n)). i.e it gives both upper and as well as lower bound.

Theta(g(n)) = { f(n) : there exists positive constants c1,c2 and n1 such that 0<=c1(g(n))<=f(n)<=c2(g(n)) for all n>=n1 }

when we say f(n)=c2(g(n)) or f(n)=c1(g(n)) it represents asymptotically tight bound.

O(n): It gives only upper bound (may or may not be tight)

O(g(n)) = { f(n) : there exists positive constants c and n1 such that 0<=f(n)<=cg(n) for all n>=n1}

ex: The bound 2*(n^2) = O(n^2) is asymptotically tight, whereas the bound 2*n = O(n^2) is not asymptotically tight.

o(n): It gives only upper bound (never a tight bound)

the notable difference between O(n) & o(n) is f(n) is less than cg(n) for all n>=n1 but not equal as in O(n).

ex: 2*n = o(n^2), but 2*(n^2) != o(n^2)

Convert JSON array to an HTML table in jQuery

I found a duplicate over here: Convert json data to a html table

Well, there are many plugins exists, including commercial one (Make this as commercial project?! Kinda overdone... but you can checkout over here: https://github.com/alfajango/jquery-dynatable)

This one has more fork: https://github.com/afshinm/Json-to-HTML-Table

//Example data, Object 
var objectArray = [{
    "Total": "34",
    "Version": "1.0.4",
    "Office": "New York"
}, {
    "Total": "67",
    "Version": "1.1.0",
    "Office": "Paris"
}];

//Example data, Array
var stringArray = ["New York", "Berlin", "Paris", "Marrakech", "Moscow"];

//Example data, nested Object. This data will create nested table also.
var nestedTable = [{
    key1: "val1",
    key2: "val2",
    key3: {
        tableId: "tblIdNested1",
        tableClassName: "clsNested",
        linkText: "Download",
        data: [{
            subkey1: "subval1",
            subkey2: "subval2",
            subkey3: "subval3"
        }]
    }
}];

Apply the code

//Only first parameter is required
var jsonHtmlTable = ConvertJsonToTable(objectArray, 'jsonTable', null, 'Download');

Or you might want to checkout this jQuery plugins as well: https://github.com/jongha/jquery-jsontotable

I think jongha's plugins is easier to use

<div id="jsontotable" class="jsontotable"></div>

var data = [[1, 2, 3], [1, 2, 3]];
$.jsontotable(data, { id: '#jsontotable', header: false });

org.springframework.web.client.HttpClientErrorException: 400 Bad Request

This is what worked for me. Issue is earlier I didn't set Content Type(header) when I used exchange method.

MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
map.add("param1", "123");
map.add("param2", "456");
map.add("param3", "789");
map.add("param4", "123");
map.add("param5", "456");

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

final HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<MultiValueMap<String, String>>(map ,
        headers);
JSONObject jsonObject = null;

try {
    RestTemplate restTemplate = new RestTemplate();
    ResponseEntity<String> responseEntity = restTemplate.exchange(
            "https://url", HttpMethod.POST, entity,
            String.class);

    if (responseEntity.getStatusCode() == HttpStatus.CREATED) {
        try {
            jsonObject = new JSONObject(responseEntity.getBody());
        } catch (JSONException e) {
            throw new RuntimeException("JSONException occurred");
        }
    }
  } catch (final HttpClientErrorException httpClientErrorException) {
        throw new ExternalCallBadRequestException();
  } catch (HttpServerErrorException httpServerErrorException) {
        throw new ExternalCallServerErrorException(httpServerErrorException);
  } catch (Exception exception) {
        throw new ExternalCallServerErrorException(exception);
    } 

ExternalCallBadRequestException and ExternalCallServerErrorException are the custom exceptions here.

Note: Remember HttpClientErrorException is thrown when a 4xx error is received. So if the request you send is wrong either setting header or sending wrong data, you could receive this exception.

How do I use Node.js Crypto to create a HMAC-SHA1 hash?

Gwerder's solution wont work because hash = hmac.read(); happens before the stream is done being finalized. Thus AngraX's issues. Also the hmac.write statement is un-necessary in this example.

Instead do this:

var crypto    = require('crypto');
var hmac;
var algorithm = 'sha1';
var key       = 'abcdeg';
var text      = 'I love cupcakes';
var hash;

hmac = crypto.createHmac(algorithm, key);

// readout format:
hmac.setEncoding('hex');
//or also commonly: hmac.setEncoding('base64');

// callback is attached as listener to stream's finish event:
hmac.end(text, function () {
    hash = hmac.read();
    //...do something with the hash...
});

More formally, if you wish, the line

hmac.end(text, function () {

could be written

hmac.end(text, 'utf8', function () {

because in this example text is a utf string

use regular expression in if-condition in bash

Adding this solution with grep and basic sh builtins for those interested in a more portable solution (independent of bash version; also works with plain old sh, on non-Linux platforms etc.)

# GLOB matching
gg=svm-grid-ch    
case "$gg" in
   *grid*) echo $gg ;;
esac

# REGEXP    
if echo "$gg" | grep '^....grid*' >/dev/null ; then echo $gg ; fi    
if echo "$gg" | grep '....grid*' >/dev/null ; then echo $gg ; fi    
if echo "$gg" | grep 's...grid*' >/dev/null ; then echo $gg ; fi    

# Extended REGEXP
if echo "$gg" | egrep '(^....grid*|....grid*|s...grid*)' >/dev/null ; then
  echo $gg
fi    

Some grep incarnations also support the -q (quiet) option as an alternative to redirecting to /dev/null, but the redirect is again the most portable.

Set value of hidden field in a form using jQuery's ".val()" doesn't work

Using ID:

$('input:hidden#texens').val('tinkumaster');

Using class:

$('input:hidden.many_texens').val('tinkumaster');

Spring MVC - HttpMediaTypeNotAcceptableException

More of a comment than an answer...

I'm using Lombok and I was developing a (very) skeleton API and my response DTO didn't have any fields (yet) and I got the HttpMediaTypeNotAcceptableException error while running my integration tests.

Adding a field to the response DTO fixed the issue.

initializing a Guava ImmutableMap

if the map is short you can do:

ImmutableMap.of(key, value, key2, value2); // ...up to five k-v pairs

If it is longer then:

ImmutableMap.builder()
   .put(key, value)
   .put(key2, value2)
   // ...
   .build();

How to find index of list item in Swift?

In case somebody has this problem

Cannot invoke initializer for type 'Int' with an argument list of type '(Array<Element>.Index?)'

jsut do this

extension Int {
    var toInt: Int {
        return self
    }
}

then

guard let finalIndex = index?.toInt else {
    return false
}

Multi-line strings in PHP

PHP has Heredoc and Nowdoc strings, which are the best way to handle multiline strings in PHP.

http://php.net/manual/en/language.types.string.php#language.types.string.syntax.heredoc

$str = <<<EOD
Example of string
spanning multiple lines
using heredoc syntax.
$var is replaced automatically.
EOD;

A Nowdoc is like a Heredoc, but it doesn't replace variables.

$str = <<<'EOD'
Example of string
spanning multiple lines
using nowdoc syntax.
$var is NOT replaced in a nowdoc.
EOD;

Beware that the end token EOD must not be indented at all, or PHP won't acknowledge it. Also, you don't have to use "EOD"; it can be any string you want.

Viewing all defined variables

a bit more smart (python 3) way:

def printvars():

   tmp = globals().copy()
   [print(k,'  :  ',v,' type:' , type(v)) for k,v in tmp.items() if not k.startswith('_') and k!='tmp' and k!='In' and k!='Out' and not hasattr(v, '__call__')]

Is it a good idea to index datetime field in mysql?

MySQL recommends using indexes for a variety of reasons including elimination of rows between conditions: http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html

This makes your datetime column an excellent candidate for an index if you are going to be using it in conditions frequently in queries. If your only condition is BETWEEN NOW() AND DATE_ADD(NOW(), INTERVAL 30 DAY) and you have no other index in the condition, MySQL will have to do a full table scan on every query. I'm not sure how many rows are generated in 30 days, but as long as it's less than about 1/3 of the total rows it will be more efficient to use an index on the column.

Your question about creating an efficient database is very broad. I'd say to just make sure that it's normalized and all appropriate columns are indexed (i.e. ones used in joins and where clauses).

Windows batch script launch program and exit console

start "" "%SystemRoot%\Notepad.exe"

Keep the "" in between start and your application path.


Added explanation:

Normally when we launch a program from a batch file like below, we'll have the black windows at the background like OP said.

%SystemRoot%\Notepad.exe

This was cause by Notepad running in same command prompt (process). The command prompt will close AFTER notepad is closed. To avoid that, we can use the start command to start a separate process like this.

start %SystemRoot%\Notepad.exe

This command is fine as long it doesn't has space in the path. To handle space in the path for just in case, we added the " quotes like this.

start "%SystemRoot%\Notepad.exe"

However running this command would just start another blank command prompt. Why? If you lookup to the start /?, the start command will recognize the argument between the " as the title of the new command prompt it is going to launch. So, to solve that, we have the command like this:

start "" "%SystemRoot%\Notepad.exe"

The first argument of "" is to set the title (which we set as blank), and the second argument of "%SystemRoot%\Notepad.exe" is the target command to run (that support spaces in the path).

If you need to add parameters to the command, just append them quoted, i.e.:

start "" "%SystemRoot%\Notepad.exe" "<filename>" 

! [rejected] master -> master (fetch first)

You should use git pull, that´s command do a git fetch and next do the git merge.

If you use a git push origin master --force command, you may have problems in the future.

Callback function for JSONP with jQuery AJAX

delete this line:

jsonp: 'jsonp_callback',

Or replace this line:

url: 'http://url.of.my.server/submit?callback=json_callback',

because currently you are asking jQuery to create a random callback function name with callback=? and then telling jQuery that you want to use jsonp_callback instead.

Convert alphabet letters to number in Python

If you are going to use this conversion a lot, consider calculating once and putting the results in a dictionary:

>>> import string
>>> di=dict(zip(string.letters,[ord(c)%32 for c in string.letters]))
>>> di['c'] 
3

The advantage is dictionary lookups are very fast vs iterating over a list on every call.

>>> for c in sorted(di.keys()):
>>>    print "{0}:{1}  ".format(c, di[c])
# what you would expect....

Parsing date string in Go

As answered but to save typing out "2006-01-02T15:04:05.000Z" for the layout, you could use the package's constant RFC3339.

str := "2014-11-12T11:45:26.371Z"
t, err := time.Parse(time.RFC3339, str)

if err != nil {
    fmt.Println(err)
}
fmt.Println(t)

https://play.golang.org/p/Dgu2ZvHwTh

how to set the background image fit to browser using html

Try This Code: It may help you

<html>
    <head>
<style>
    body
        {
            background:url('images/top-left.jpg') no-repeat center center fixed;
            background-size: cover;
            -webkit-background-size: cover;
            -moz-background-size: cover;
            -o-background-size: cover;
            margin: 0;
            padding: 0;
        }

    </style>
</head>
    <body>
    <form action="LoginCheck.jsp"method="post">
    </br>Username:<input type="text" name="username">
    </br>Password:<input type="password" name="password">
    </br>
    <input type="submit" value="Submit">
    </form>
    </center> 
    </body>


</html>

How to delete columns that contain ONLY NAs?

Because performance was really important for me, I benchmarked all the functions above.

NOTE: Data from @Simon O'Hanlon's post. Only with size 15000 instead of 10.

library(tidyverse)
library(microbenchmark)

set.seed(123)
df <- data.frame(id = 1:15000,
                 nas = rep(NA, 15000), 
                 vals = sample(c(1:3, NA), 15000,
                               repl = TRUE))
df

MadSconeF1 <- function(x) x[, colSums(is.na(x)) != nrow(x)]

MadSconeF2 <- function(x) x[colSums(!is.na(x)) > 0]

BradCannell <- function(x) x %>% select_if(~sum(!is.na(.)) > 0)

SimonOHanlon <- function(x) x[ , !apply(x, 2 ,function(y) all(is.na(y)))]

jsta <- function(x) janitor::remove_empty(x)

SiboJiang <- function(x) x %>% dplyr::select_if(~!all(is.na(.)))

akrun <- function(x) Filter(function(y) !all(is.na(y)), x)

mbm <- microbenchmark(
  "MadSconeF1" = {MadSconeF1(df)},
  "MadSconeF2" = {MadSconeF2(df)},
  "BradCannell" = {BradCannell(df)},
  "SimonOHanlon" = {SimonOHanlon(df)},
  "SiboJiang" = {SiboJiang(df)},
  "jsta" = {jsta(df)}, 
  "akrun" = {akrun(df)},
  times = 1000)

mbm

Results:

Unit: microseconds
         expr    min      lq      mean  median      uq      max neval  cld
   MadSconeF1  154.5  178.35  257.9396  196.05  219.25   5001.0  1000 a   
   MadSconeF2  180.4  209.75  281.2541  226.40  251.05   6322.1  1000 a   
  BradCannell 2579.4 2884.90 3330.3700 3059.45 3379.30  33667.3  1000    d
 SimonOHanlon  511.0  565.00  943.3089  586.45  623.65 210338.4  1000  b  
    SiboJiang 2558.1 2853.05 3377.6702 3010.30 3310.00  89718.0  1000    d
         jsta 1544.8 1652.45 2031.5065 1706.05 1872.65  11594.9  1000   c 
        akrun   93.8  111.60  139.9482  121.90  135.45   3851.2  1000 a


autoplot(mbm)

enter image description here

mbm %>% 
  tbl_df() %>%
  ggplot(aes(sample = time)) + 
  stat_qq() + 
  stat_qq_line() +
  facet_wrap(~expr, scales = "free")

enter image description here

Swift presentViewController

For reference, because this question is one of the first Google result.

Breaking change in Swift 3:

The method presentViewController is replaced by the method present.

You can use it like the old one:

self.present(viewControllerToPresent, animated: true, completion: nil)

Example to open the camera:

let imagePicker = UIImagePickerController()
imagePicker.delegate = self
imagePicker.sourceType = UIImagePickerControllerSourceType.camera
imagePicker.allowsEditing = false
self.present(imagePicker, animated: true, completion: nil)

How to rsync only a specific list of files?

This answer is not the direct answer for the question. But it should help you figure out which solution fits best for your problem.

When analysing the problem you should activate the debug option -vv

Then rsync will output which files are included or excluded by which pattern:

building file list ... 
[sender] hiding file FILE1 because of pattern FILE1*
[sender] showing file FILE2 because of pattern *

How do you get the contextPath from JavaScript, the right way?

I render context path to attribute of link tag with id="contextPahtHolder" and then obtain it in JS code. For example:

<html>
    <head>
        <link id="contextPathHolder" data-contextPath="${pageContext.request.contextPath}"/>
    <body>
        <script src="main.js" type="text/javascript"></script>
    </body>
</html>

main.js

var CONTEXT_PATH = $('#contextPathHolder').attr('data-contextPath');
$.get(CONTEXT_PATH + '/action_url', function() {});

If context path is empty (like in embedded servlet container istance), it will be empty string. Otherwise it contains contextPath string

Replace all double quotes within String

String info = "Hello \"world\"!";
info = info.replace("\"", "\\\"");

String info1 = "Hello "world!";
info1 = info1.replace('"', '\"').replace("\"", "\\\"");

For the 2nd field info1, 1st replace double quotes with an escape character.

External resource not being loaded by AngularJs

Whitelist the resource with $sceDelegateProvider

This is caused by a new security policy put in place in Angular 1.2. It makes XSS harder by preventing a hacker from dialling out (i.e. making a request to a foreign URL, potentially containing a payload).

To get around it properly you need to whitelist the domains you want to allow, like this:

angular.module('myApp',['ngSanitize']).config(function($sceDelegateProvider) {
  $sceDelegateProvider.resourceUrlWhitelist([
    // Allow same origin resource loads.
    'self',
    // Allow loading from our assets domain.  Notice the difference between * and **.
    'http://srv*.assets.example.com/**'
  ]);

  // The blacklist overrides the whitelist so the open redirect here is blocked.
  $sceDelegateProvider.resourceUrlBlacklist([
    'http://myapp.example.com/clickThru**'
  ]);
});

This example is lifted from the documentation which you can read here:

https://docs.angularjs.org/api/ng/provider/$sceDelegateProvider

Be sure to include ngSanitize in your app to make this work.

Disabling the feature

If you want to turn off this useful feature, and you're sure your data is secure, you can simply allow **, like so:

angular.module('app').config(function($sceDelegateProvider) {
  $sceDelegateProvider.resourceUrlWhitelist(['**']);
});

How to split a delimited string in Ruby and convert it to an array?

the simplest way to convert a string that has a delimiter like a comma is just to use the split method

"1,2,3,4".split(',') # "1", "2", "3", "4"]

you can find more info on how to use the split method in the ruby docs

Divides str into substrings based on a delimiter, returning an array of these substrings.

If pattern is a String, then its contents are used as the delimiter when splitting str. If pattern is a single space, str is split on whitespace, with leading whitespace and runs of contiguous whitespace characters ignored.

If pattern is a Regexp, str is divided where the pattern matches. Whenever the pattern matches a zero-length string, str is split into individual characters. If pattern contains groups, the respective matches will be returned in the array as well.

If pattern is omitted, the value of $; is used. If $; is nil (which is the default), str is split on whitespace as if ` ‘ were specified.

If the limit parameter is omitted, trailing null fields are suppressed. If limit is a positive number, at most that number of fields will be returned (if limit is 1, the entire string is returned as the only entry in an array). If negative, there is no limit to the number of fields returned, and trailing null fields are not suppressed.

Use of Java's Collections.singletonList()?

The javadoc says this:

"Returns an immutable list containing only the specified object. The returned list is serializable."

You ask:

Why would I want to have a separate method to do that?

Primarily as a convenience ... to save you having to write a sequence of statements to:

  • create an empty list object
  • add an element to it, and
  • wrap it with an immutable wrapper.

It may also be a bit faster and/or save a bit of memory, but it is unlikely that these small savings will be significant. (An application that creates vast numbers of singleton lists is unusual to say the least.)

How does immutability play a role here?

It is part of the specification of the method; see above.

Are there any special useful use-cases for this method, rather than just being a convenience method?

Clearly, there are use-cases where it is convenient to use the singletonList method. But I don't know how you would (objectively) distinguish between an ordinary use-case and a "specially useful" one ...

Delete duplicate records from a SQL table without a primary key

delete sub from (select ROW_NUMBER() OVer(Partition by empid order by empid)cnt from employee)sub where sub.cnt>1

What is the difference between 127.0.0.1 and localhost

There is nothing different. One is easier to remember than the other. Generally, you define a name to associate with an IP address. You don't have to specify localhost for 127.0.0.1, you could specify any name you want.

./xx.py: line 1: import: command not found

It's about Shebang

#!usr/bin/python

This will tell which interpreter to wake up to run the code written in file.

Pytesseract : "TesseractNotFound Error: tesseract is not installed or it's not in your path", how do I fix this?

# {Windows 10 instructions}
# before you use the script you need to install the dependence
# 1. download the tesseract from the official link:
#   https://github.com/UB-Mannheim/tesseract/wiki
# 2. install the tesseract
#   i chosed this path
#       *replace the user string in the below path with you name of user that you are using in your current machine
#       C:\Users\user\AppData\Local\Tesseract-OCR\
# 3. Install the  pillow for your python version
# * the best way for me is to install is this form(i'am using python3.7 version and in my CMD i run this version of python by     typing py -3.7):
# * if you are using another version of python first look how you start the python from you CMD
# * for some machine the run of python from the CMD is different
    # [examples]
    # =================================
    # PYTHON VERSION 3.7
    # python
    # python3.7
    # python -3.7
    # python 3.7
    # python3
    # python -3
    # python 3
    # py3.7
    # py -3.7
    # py 3.7
    # py3
    # py -3
    # py 3
    # PYTHON VERSION 3.6
    # python
    # python3.6
    # python -3.6
    # python 3.6
    # python3
    # python -3
    # python 3
    # py3.6
    # py -3.6
    # py 3.6
    # py3
    # py -3
    # py 3
    # PYTHON VERSION 2.7
    # python
    # python2.7
    # python -2.7
    # python 2.7
    # python2
    # python -2
    # python 2
    # py2.7
    # py -2.7
    # py 2.7
    # py2
    # py -2
    # py 2
    # ================================
# we are using pip to install the dependences
# because for me i start the python version 3.7 with the following line 
    # py -3.7
# open the CMD in windows machine and type the following line:
    # py -3.7 -m pip install pillow
# 4. Install the  pytesseract and tesseract for your python version
# * the best way for me is to install is this form(i'am using python3.7 version and in my CMD i run this version of python by     typing py -3.7):
# we are using pip to install the dependences
# open the CMD in windows machine and type the following lines:
    # py -3.7 -m pip install pytesseract
    # py -3.7 -m pip install tesseract


#!/usr/bin/python
from PIL import Image
import pytesseract
import os
import getpass

def extract_text_from_image(image_file_name_arg):

    # IMPORTANT
    # if you have followed my instructions to install this dependence in above text explanatin
    # for my machine is
    # if you don't put the right path for tesseract.exe the script will not work
    username = getpass.getuser()
    # here above line get the username for your machine automatically
    tesseract_exe_path_installation="C:\\Users\\"+username+"\\AppData\\Local\\Tesseract-OCR\\tesseract.exe"
    pytesseract.pytesseract.tesseract_cmd=tesseract_exe_path_installation

# specify the direction of your image files manually or use line bellow if the images are in the script directory in     folder  images
    # image_dir="D:\\GIT\\ai_example\\extract_text_from_image\\images"
    image_dir=os.getcwd()+"\\images"
    dir_seperator="\\"
    image_file_name=image_file_name_arg
    # if your image are in different format change the extension(ex. ".png")
    image_ext=".jpg"
    image_path_dir=image_dir+dir_seperator+image_file_name+image_ext

    print("=============================================================================")
    print("image used is in the following path dir:")
    print("\t"+image_path_dir)
    print("=============================================================================")

    img=Image.open(image_path_dir)
    text=pytesseract.image_to_string(img, lang="eng")
    print(text)

# change the name "image_1" whith the name without extension for your image name
# image_file_name_arg="image_1"
image_file_name_arg="image_2"
# image_file_name_arg="image_3"
# image_file_name_arg="image_4"
# image_file_name_arg="image_5"
extract_text_from_image(image_file_name_arg)

# ==================================
# CREATED BY: SHERIFI
# e-mail: [email protected]
# git-link for script: https://github.com/sherifi/ai_example.git
# ==================================

Angular2 QuickStart npm start is not working correctly

In my case ,I just needed to add a dummy .ts file.So I created a test.ts file with no contents and ran npm start to solve the problem.

Java 256-bit AES Password-Based Encryption

Consider using Encryptor4j of which I am the author.

First make sure you have Unlimited Strength Jurisdiction Policy files installed before your proceed so that you can use 256-bit AES keys.

Then do the following:

String password = "mysupersecretpassword"; 
Key key = KeyFactory.AES.keyFromPassword(password.toCharArray());
Encryptor encryptor = new Encryptor(key, "AES/CBC/PKCS7Padding", 16);

You can now use the encryptor to encrypt your message. You can also perform streaming encryption if you'd like. It automatically generates and prepends a secure IV for your convenience.

If it's a file that you wish to compress take a look at this answer Encrypting a large file with AES using JAVA for an even simpler approach.

ImportError: No module named tensorflow

Check if Tensorflow was installed successfully using:

 pip3 show tensorflow

If you get something like

Name: tensorflow
Version: 1.2.1
Summary: TensorFlow helps the tensors flow
Home-page: http://tensorflow.org/
Author: Google Inc.
Author-email: [email protected]
License: Apache 2.0
Location: /usr/local/lib/python3.5/dist-packages
Requires: bleach, markdown, html5lib, backports.weakref, werkzeug, numpy, protobuf, wheel, six

You may try adding the path of your tensorflow location by:

export PYTHONPATH=/your/tensorflow/path:$PYTHONPATH.

How to handle Pop-up in Selenium WebDriver using Java

You can use the below code inside your code when you get any web browser pop-up alert message box.

// Accepts (Click on OK) Chrome Alert Browser for RESET button.

Alert alertOK = driver.switchTo().alert();
alertOK.accept();



//Rejects (Click on Cancel) Chrome Browser Alert for RESET button.

Alert alertCancel = driver.switchTo().alert();
alertCancel.dismiss();

Getting full JS autocompletion under Sublime Text

As already mentioned, tern.js is a new and promising project with plugins for Sublime Text, Vim and Emacs. I´ve been using TernJS for Sublime for a while and the suggestions I get are way better than the standard ones:

enter image description here

Tern scans all .js files in your project. You can get support for DOM, nodejs, jQuery, and more by adding "libs" in your .sublime-project file:

"ternjs": {
    "exclude": ["wordpress/**", "node_modules/**"],
    "libs": ["browser", "jquery"],
    "plugins": {
        "requirejs": {
            "baseURL": "./js"
        }
    }
}

enter image description here

Why es6 react component works only with "export default"?

Exporting without default means it's a "named export". You can have multiple named exports in a single file. So if you do this,

class Template {}
class AnotherTemplate {}

export { Template, AnotherTemplate }

then you have to import these exports using their exact names. So to use these components in another file you'd have to do,

import {Template, AnotherTemplate} from './components/templates'

Alternatively if you export as the default export like this,

export default class Template {}

Then in another file you import the default export without using the {}, like this,

import Template from './components/templates'

There can only be one default export per file. In React it's a convention to export one component from a file, and to export it is as the default export.

You're free to rename the default export as you import it,

import TheTemplate from './components/templates'

And you can import default and named exports at the same time,

import Template,{AnotherTemplate} from './components/templates'

How to get the nth occurrence in a string?

Because recursion is always the answer.

function getPosition(input, search, nth, curr, cnt) {
    curr = curr || 0;
    cnt = cnt || 0;
    var index = input.indexOf(search);
    if (curr === nth) {
        if (~index) {
            return cnt;
        }
        else {
            return -1;
        }
    }
    else {
        if (~index) {
            return getPosition(input.slice(index + search.length),
              search,
              nth,
              ++curr,
              cnt + index + search.length);
        }
        else {
            return -1;
        }
    }
}

How to sort an STL vector?

Overload less than operator, then sort. This is an example I found off the web...

class MyData
{
public:
  int m_iData;
  string m_strSomeOtherData;
  bool operator<(const MyData &rhs) const { return m_iData < rhs.m_iData; }
};

std::sort(myvector.begin(), myvector.end());

Source: here

Easiest way to toggle 2 classes in jQuery

If your element exposes class A from the start, you can write:

$(element).toggleClass("A B");

This will remove class A and add class B. If you do that again, it will remove class B and reinstate class A.

If you want to match the elements that expose either class, you can use a multiple class selector and write:

$(".A, .B").toggleClass("A B");

android image button

just use a Button with android:drawableRight properties like this:

<Button android:id="@+id/btnNovaCompra" android:layout_width="wrap_content"
        android:text="@string/btn_novaCompra"
        android:gravity="center"
        android:drawableRight="@drawable/shoppingcart"
        android:layout_height="wrap_content"/>

How to import CSV file data into a PostgreSQL table?

You could also use pgAdmin, which offers a GUI to do the import. That's shown in this SO thread. The advantage of using pgAdmin is that it also works for remote databases.

Much like the previous solutions though, you would need to have your table on the database already. Each person has his own solution but what I usually do is open the CSV in Excel, copy the headers, paste special with transposition on a different worksheet, place the corresponding data type on the next column then just copy and paste that to a text editor together with the appropriate SQL table creation query like so:

CREATE TABLE my_table (
    /*paste data from Excel here for example ... */
    col_1 bigint,
    col_2 bigint,
    /* ... */
    col_n bigint 
)

Should I use .done() and .fail() for new jQuery AJAX code instead of success and error

When we are going to migrate JQuery from 1.x to 2x or 3.x in our old existing application , then we will use .done,.fail instead of success,error as JQuery up gradation is going to be deprecated these methods.For example when we make a call to server web methods then server returns promise objects to the calling methods(Ajax methods) and this promise objects contains .done,.fail..etc methods.Hence we will the same for success and failure response. Below is the example(it is for POST request same way we can construct for request type like GET...)

 $.ajax({
            type: "POST",
            url: url,
            data: '{"name" :"sheo"}',
            contentType: "application/json; charset=utf-8",
            async: false,
            cache: false
            }).done(function (Response) {
                  //do something when get response            })
           .fail(function (Response) {
                    //do something when any error occurs.
                });

Removing duplicate rows from table in Oracle

To select the duplicates only the query format can be:

SELECT GroupFunction(column1), GroupFunction(column2),..., 
COUNT(column1), column1, column2...
FROM our_table
GROUP BY column1, column2, column3...
HAVING COUNT(column1) > 1

So the correct query as per other suggestion is:

DELETE FROM tablename a
      WHERE a.ROWID > ANY (SELECT b.ROWID
                             FROM tablename b
                            WHERE a.fieldname = b.fieldname
                              AND a.fieldname2 = b.fieldname2
                              AND ....so on.. to identify the duplicate rows....)

This query will keep the oldest record in the database for the criteria chosen in the WHERE CLAUSE.

Oracle Certified Associate (2008)

How do I delete virtual interface in Linux?

You can use sudo ip link delete to remove the interface.

What is [Serializable] and when should I use it?

Some practical uses for the [Serializable] attribute:

  • Saving object state using binary serialisation; you can very easily 'save' entire object instances in your application to a file or network stream and then recreate them by deserialising - check out the BinaryFormatter class in System.Runtime.Serialization.Formatters.Binary
  • Writing classes whose object instances can be stored on the clipboard using Clipboard.SetData() - nonserialisable classes cannot be placed on the clipboard.
  • Writing classes which are compatible with .NET Remoting; generally, any class instance you pass between application domains (except those which extend from MarshalByRefObject) must be serialisable.

These are the most common usage cases that I have come across.

Grep and Python

Concise and memory efficient:

#!/usr/bin/env python
# file: grep.py
import re, sys

map(sys.stdout.write,(l for l in sys.stdin if re.search(sys.argv[1],l)))

It works like egrep (without too much error handling), e.g.:

cat input-file | grep.py "RE"

And here is the one-liner:

cat input-file | python -c "import re,sys;map(sys.stdout.write,(l for l in sys.stdin if re.search(sys.argv[1],l)))" "RE"

Why does Python code use len() function instead of a length method?

Strings do have a length method: __len__()

The protocol in Python is to implement this method on objects which have a length and use the built-in len() function, which calls it for you, similar to the way you would implement __iter__() and use the built-in iter() function (or have the method called behind the scenes for you) on objects which are iterable.

See Emulating container types for more information.

Here's a good read on the subject of protocols in Python: Python and the Principle of Least Astonishment

Java socket API: How to tell if a connection has been closed?

I think this is nature of tcp connections, in that standards it takes about 6 minutes of silence in transmission before we conclude that out connection is gone! So I don`t think you can find an exact solution for this problem. Maybe the better way is to write some handy code to guess when server should suppose a user connection is closed.

Could not open input file: artisan

-> cd ..

-> cd project_dir

-> php artisan ('works fine')

in my case, i removed the directory and again clone the repo from the same directory through terminal. then i went one step back and step into my project folder again and the problem was gone.

What is your single most favorite command-line trick using Bash?

bash can redirect to and from TCP/IP sockets. /dev/tcp/ and /dev/udp.

Some people think it's a security issue, but that's what OS level security like Solaris X's jail is for.

As Will Robertson notes, change prompt to do stuff... print the command # for !nn Set the Xterm terminal name. If it's an old Xterm that doesn't sniff traffic to set it's title.

change html input type by JS?

_x000D_
_x000D_
$(".show-pass").click(function (e) {_x000D_
    e.preventDefault();_x000D_
    var type = $("#signupform-password").attr('type');_x000D_
    switch (type) {_x000D_
        case 'password':_x000D_
        {_x000D_
            $("#signupform-password").attr('type', 'text');_x000D_
            return;_x000D_
        }_x000D_
        case 'text':_x000D_
        {_x000D_
            $("#signupform-password").attr('type', 'password');_x000D_
            return;_x000D_
        }_x000D_
    }_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input type="text" name="password" class="show-pass">
_x000D_
_x000D_
_x000D_

Determine if running on a rooted device

http://code.google.com/p/roottools/

If you do not want to use the jar file just use the code:

public static boolean findBinary(String binaryName) {
        boolean found = false;
        if (!found) {
            String[] places = { "/sbin/", "/system/bin/", "/system/xbin/",
                    "/data/local/xbin/", "/data/local/bin/",
                    "/system/sd/xbin/", "/system/bin/failsafe/", "/data/local/" };
            for (String where : places) {
                if (new File(where + binaryName).exists()) {
                    found = true;

                    break;
                }
            }
        }
        return found;
    }

Program will try to find su folder:

private static boolean isRooted() {
        return findBinary("su");
    }

Example:

if (isRooted()) {
   textView.setText("Device Rooted");

} else {
   textView.setText("Device Unrooted");
}

What is the result of % in Python?

I have found that the easiest way to grasp the modulus operator (%) is through long division. It is the remainder and can be useful in determining a number to be even or odd:

4%2 = 0

  2
2|4
 -4
  0


11%3 = 2

  3
3|11
 -9
  2

Add class to an element in Angular 4

Use [ngClass] and conditionally apply class based on the id.

In your HTML file:

<li>
    <img [ngClass]="{'this-is-a-class': id === 1 }" id="1"  
         src="../../assets/images/1.jpg" (click)="addClass(id=1)"/>
</li>
<li>
    <img [ngClass]="{'this-is-a-class': id === 2 }" id="2"  
         src="../../assets/images/2.png" (click)="addClass(id=2)"/>
</li>

In your TypeScript file:

addClass(id: any) {
    this.id = id;
}

Addition for BigDecimal

BigDecimal test = new BigDecimal(0);
System.out.println(test);
test = test.add(new BigDecimal(30));
System.out.println(test);
test = test.add(new BigDecimal(45));
System.out.println(test);

Set session variable in laravel

For example, To store data in the session, you will typically use the putmethod or the session helper:

// Via a request instance...
$request->session()->put('key', 'value');

or

// Via the global helper...
session(['key' => 'value']);

for retrieving an item from the session, you can use get :

$value = $request->session()->get('key', 'default value');

or global session helper :

$value = session('key', 'default value');

To determine if an item is present in the session, you may use the has method:

if ($request->session()->has('users')) {
//
}

How to setup virtual environment for Python in VS Code?

P.S:

  • I have been using vs code for a while now and found an another way to show virtual environments in vs code.

  • Go to the parent folder in which venv is there through command prompt.

  • Type code . and Enter. [Working on both windows and linux for me.]

  • That should also show the virtual environments present in that folder.

Original Answer

I almost run into same problem everytime I am working on VS-Code using venv. I follow below steps, hope it helps:

  1. Go to File > preferences > Settings.

  2. Click on Workspace settings.

  3. Under Files:Association, in the JSON: Schemas section, you will find Edit in settings.json , click on that.

  4. Update "python.pythonPath": "Your_venv_path/bin/python" under workspace settings. (For Windows): Update "python.pythonPath": "Your_venv_path/Scripts/python.exe" under workspace settings.

  5. Restart VSCode incase if it still doesn't show your venv.

HTML form with side by side input fields

I would go with Larry K's solution, but you can also set the display to inline-block if you want the benefits of both block and inline elements.

You can do this in the div tag by inserting:

style="display:inline-block;"

Or in a CSS stylesheet with this method:

div { display:inline-block; }

Hope it helps, but as earlier mentioned, I would personally go for Larry K's solution ;-)

How to convert std::string to LPCSTR?

Using LPWSTR you could change contents of string where it points to. Using LPCWSTR you couldn't change contents of string where it points to.

std::string s = SOME_STRING;
// get temporary LPSTR (not really safe)
LPSTR pst = &s[0];
// get temporary LPCSTR (pretty safe)
LPCSTR pcstr = s.c_str();
// convert to std::wstring
std::wstring ws; 
ws.assign( s.begin(), s.end() );
// get temporary LPWSTR (not really safe)
LPWSTR pwst = &ws[0];
// get temporary LPCWSTR (pretty safe)
LPCWSTR pcwstr = ws.c_str();

LPWSTR is just a pointer to original string. You shouldn't return it from function using the sample above. To get not temporary LPWSTR you should made a copy of original string on the heap. Check the sample below:

LPWSTR ConvertToLPWSTR( const std::string& s )
{
  LPWSTR ws = new wchar_t[s.size()+1]; // +1 for zero at the end
  copy( s.begin(), s.end(), ws );
  ws[s.size()] = 0; // zero at the end
  return ws;
}

void f()
{
  std::string s = SOME_STRING;
  LPWSTR ws = ConvertToLPWSTR( s );

  // some actions

  delete[] ws; // caller responsible for deletion
}

Format timedelta to string

Following Joe's example value above, I'd use the modulus arithmetic operator, thusly:

td = datetime.timedelta(hours=10.56)
td_str = "%d:%d" % (td.seconds/3600, td.seconds%3600/60)

Note that integer division in Python rounds down by default; if you want to be more explicit, use math.floor() or math.ceil() as appropriate.

Parsing JSON Array within JSON Object

mainJSON.getJSONArray("source") returns a JSONArray, hence you can remove the new JSONArray.

The JSONArray contructor with an object parameter expects it to be a Collection or Array (not JSONArray)

Try this:

JSONArray jsonMainArr = mainJSON.getJSONArray("source"); 

What are the uses of "using" in C#?

In conclusion, when you use a local variable of a type that implements IDisposable, always, without exception, use using1.

If you use nonlocal IDisposable variables, then always implement the IDisposable pattern.

Two simple rules, no exception1. Preventing resource leaks otherwise is a real pain in the *ss.


1): The only exception is – when you're handling exceptions. It might then be less code to call Dispose explicitly in the finally block.

How do I measure a time interval in C?

High resolution timers that provide a resolution of 1 microsecond are system-specific, so you will have to use different methods to achieve this on different OS platforms. You may be interested in checking out the following article, which implements a cross-platform C++ timer class based on the functions described below:

  • [Song Ho Ahn - High Resolution Timer][1]

Windows

The Windows API provides extremely high resolution timer functions: QueryPerformanceCounter(), which returns the current elapsed ticks, and QueryPerformanceFrequency(), which returns the number of ticks per second.

Example:

#include <stdio.h>
#include <windows.h>                // for Windows APIs

int main(void)
{
    LARGE_INTEGER frequency;        // ticks per second
    LARGE_INTEGER t1, t2;           // ticks
    double elapsedTime;

    // get ticks per second
    QueryPerformanceFrequency(&frequency);

    // start timer
    QueryPerformanceCounter(&t1);

    // do something
    // ...

    // stop timer
    QueryPerformanceCounter(&t2);

    // compute and print the elapsed time in millisec
    elapsedTime = (t2.QuadPart - t1.QuadPart) * 1000.0 / frequency.QuadPart;
    printf("%f ms.\n", elapsedTime);
}

Linux, Unix, and Mac

For Unix or Linux based system, you can use gettimeofday(). This function is declared in "sys/time.h".

Example:

#include <stdio.h>
#include <sys/time.h>                // for gettimeofday()

int main(void)
{
    struct timeval t1, t2;
    double elapsedTime;

    // start timer
    gettimeofday(&t1, NULL);

    // do something
    // ...

    // stop timer
    gettimeofday(&t2, NULL);

    // compute and print the elapsed time in millisec
    elapsedTime = (t2.tv_sec - t1.tv_sec) * 1000.0;      // sec to ms
    elapsedTime += (t2.tv_usec - t1.tv_usec) / 1000.0;   // us to ms
    printf("%f ms.\n", elapsedTime);
}

Open web in new tab Selenium + Python

Strangely, so many answers, and all of them are using surrogates like JS and keyboard shortcuts instead of just using a selenium feature:

def newTab(driver, url="about:blank"):
    wnd = driver.execute(selenium.webdriver.common.action_chains.Command.NEW_WINDOW)
    handle = wnd["value"]["handle"]
    driver.switch_to.window(handle)
    driver.get(url) # changes the handle
    return driver.current_window_handle

How to insert pandas dataframe via mysqldb into database?

You might output your DataFrame as a csv file and then use mysqlimport to import your csv into your mysql.

EDIT

Seems pandas's build-in sql util provide a write_frame function but only works in sqlite.

I found something useful, you might try this

How to extract the decision rules from scikit-learn decision-tree?

Now you can use export_text.

from sklearn.tree import export_text

r = export_text(loan_tree, feature_names=(list(X_train.columns)))
print(r)

A complete example from [sklearn][1]

from sklearn.datasets import load_iris
from sklearn.tree import DecisionTreeClassifier
from sklearn.tree import export_text
iris = load_iris()
X = iris['data']
y = iris['target']
decision_tree = DecisionTreeClassifier(random_state=0, max_depth=2)
decision_tree = decision_tree.fit(X, y)
r = export_text(decision_tree, feature_names=iris['feature_names'])
print(r)

How to change font size in html?

You can't do it in HTML. You can in CSS. Create a new CSS file and write:

p {
 font-size: (some number);
}

If that doesn't work make sure you don't have any "pre" tags, which make your code a bit smaller.

Get next / previous element using JavaScript?

Really depends on the overall structure of your document.

If you have:

<div></div>
<div></div>
<div></div>

it may be as simple as traversing through using

mydiv.nextSibling;
mydiv.previousSibling;

However, if the 'next' div could be anywhere in the document you'll need a more complex solution. You could try something using

document.getElementsByTagName("div");

and running through these to get where you want somehow.

If you are doing lots of complex DOM traversing such as this I would recommend looking into a library such as jQuery.

Apply CSS styles to an element depending on its child elements

In my case, I had to change the cell padding of an element that contained an input checkbox for a table that's being dynamically rendered with DataTables:

<td class="dt-center">
    <input class="a" name="constCheck" type="checkbox" checked="">
</td>

After implementing the following line code within the initComplete function I was able to produce the correct padding, which fixed the rows from being displayed with an abnormally large height

 $('tbody td:has(input.a)').css('padding', '0px');

Now, you can see that the correct styles are being applied to the parent element:

<td class=" dt-center" style="padding: 0px;">
    <input class="a" name="constCheck" type="checkbox" checked="">
</td>

Essentially, this answer is an extension of @KP's answer, but the more collaboration of implementing this the better. In summation, I hope this helps someone else because it works! Lastly, thank you so much @KP for leading me in the right direction!

Is it necessary to assign a string to a variable before comparing it to another?

Do I really have to create an NSString for "Wrong"?

No, why not just do:

if([statusString isEqualToString:@"Wrong"]){
    //doSomething;
}

Using @"" simply creates a string literal, which is a valid NSString.

Also, can I compare the value of a UILabel.text to a string without assigning the label value to a string?

Yes, you can do something like:

UILabel *label = ...;
if([someString isEqualToString:label.text]) {
    // Do stuff here 
}

Best way to define private methods for a class in Objective-C

There isn't, as others have already said, such a thing as a private method in Objective-C. However, starting in Objective-C 2.0 (meaning Mac OS X Leopard, iPhone OS 2.0, and later) you can create a category with an empty name (i.e. @interface MyClass ()) called Class Extension. What's unique about a class extension is that the method implementations must go in the same @implementation MyClass as the public methods. So I structure my classes like this:

In the .h file:

@interface MyClass {
    // My Instance Variables
}

- (void)myPublicMethod;

@end

And in the .m file:

@interface MyClass()

- (void)myPrivateMethod;

@end

@implementation MyClass

- (void)myPublicMethod {
    // Implementation goes here
}

- (void)myPrivateMethod {
    // Implementation goes here
}

@end

I think the greatest advantage of this approach is that it allows you to group your method implementations by functionality, not by the (sometimes arbitrary) public/private distinction.

Generic type conversion FROM string

public class TypedProperty<T> : Property
{
    public T TypedValue
    {
        get { return (T)(object)base.Value; }
        set { base.Value = value.ToString();}
    }
}

I using converting via an object. It is a little bit simpler.

HTML Input Type Date, Open Calendar by default

This is not possible with native HTML input elements. You can use webshim polyfill, which gives you this option by using this markup.

<input type="date" data-date-inline-picker="true" />

Here is a small demo

Ruby: How to iterate over a range, but in set increments?

You can use Numeric#step.

0.step(30,5) do |num|
  puts "number is #{num}"
end
# >> number is 0
# >> number is 5
# >> number is 10
# >> number is 15
# >> number is 20
# >> number is 25
# >> number is 30

JavaScript before leaving the page

Normally you want to show this message, when the user has made changes in a form, but they are not saved.

Take this approach to show a message, only when the user has changed something

var form = $('#your-form'),
  original = form.serialize()

form.submit(function(){
  window.onbeforeunload = null
})

window.onbeforeunload = function(){
  if (form.serialize() != original)
    return 'Are you sure you want to leave?'
}

Redirecting output to $null in PowerShell, but ensuring the variable remains set

Warning messages should be written using the Write-Warning cmdlet, which allows the warning messages to be suppressed with the -WarningAction parameter or the $WarningPreference automatic variable. A function needs to use CmdletBinding to implement this feature.

function WarningTest {
    [CmdletBinding()]
    param($n)

    Write-Warning "This is a warning message for: $n."
    "Parameter n = $n"
}

$a = WarningTest 'test one' -WarningAction SilentlyContinue

# To turn off warnings for multiple commads,
# use the WarningPreference variable
$WarningPreference = 'SilentlyContinue'
$b = WarningTest 'test two'
$c = WarningTest 'test three'
# Turn messages back on.
$WarningPreference = 'Continue'
$c = WarningTest 'test four'

To make it shorter at the command prompt, you can use -wa 0:

PS> WarningTest 'parameter alias test' -wa 0

Write-Error, Write-Verbose and Write-Debug offer similar functionality for their corresponding types of messages.

Explode string by one or more spaces or tabs

Explode string by one or more spaces or tabs in php example as follow: 

   <?php 
       $str = "test1 test2   test3        test4"; 
       $result = preg_split('/[\s]+/', $str);
       var_dump($result);  
    ?>

   /** To seperate by spaces alone: **/
    <?php
      $string = "p q r s t";   
      $res = preg_split('/ +/', $string);
      var_dump($res);
    ?>

javascript popup alert on link click

In order to do this you need to attach the handler to a specific anchor on the page. For operations like this it's much easier to use a standard framework like jQuery. For example if I had the following HTML

HTML:

<a id="theLink">Click Me</a>

I could use the following jQuery to hookup an event to that specific link.

// Use ready to ensure document is loaded before running javascript
$(document).ready(function() {

  // The '#theLink' portion is a selector which matches a DOM element
  // with the id 'theLink' and .click registers a call back for the 
  // element being clicked on 
  $('#theLink').click(function (event) {

    // This stops the link from actually being followed which is the 
    // default action 
    event.preventDefault();

    var answer confirm("Please click OK to continue");
    if (!answer) {
      window.location="http://www.continue.com"
    }
  });

});

How to access component methods from “outside” in ReactJS?

React provides an interface for what you are trying to do via the ref attribute. Assign a component a ref, and its current attribute will be your custom component:

class Parent extends React.Class {
    constructor(props) {
        this._child = React.createRef();
    }

    componentDidMount() {
        console.log(this._child.current.someMethod()); // Prints 'bar'
    }

    render() {
        return (
            <div>
                <Child ref={this._child} />
            </div>
        );
    }
}

Note: This will only work if the child component is declared as a class, as per documentation found here: https://facebook.github.io/react/docs/refs-and-the-dom.html#adding-a-ref-to-a-class-component

Update 2019-04-01: Changed example to use a class and createRef per latest React docs.

Update 2016-09-19: Changed example to use ref callback per guidance from the ref String attribute docs.

How do I enable TODO/FIXME/XXX task tags in Eclipse?

For me, such tags are enabled by default. You can configure which task tags should be used in the workspace options: Java > Compiler > Task tags

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Check if they are enabled in this location, and that should be enough to have them appear in the Task list (or the Markers view).

Extra note: reinstalling Eclipse won't change anything most of the time if you work on the same workspace. Most settings used by Eclipse are stored in the .metadata folder, in your workspace folder.

Open Excel file for reading with VBA without display

If that suits your needs, I would simply use

Application.ScreenUpdating = False

with the added benefit of accelerating your code, instead of slowing it down by using a second instance of Excel.

Calling class staticmethod within the class body?

This is the way I prefer:

class Klass(object):

    @staticmethod
    def stat_func():
        return 42

    _ANS = stat_func.__func__()

    def method(self):
        return self.__class__.stat_func() + self.__class__._ANS

I prefer this solution to Klass.stat_func, because of the DRY principle. Reminds me of the reason why there is a new super() in Python 3 :)

But I agree with the others, usually the best choice is to define a module level function.

For instance with @staticmethod function, the recursion might not look very good (You would need to break DRY principle by calling Klass.stat_func inside Klass.stat_func). That's because you don't have reference to self inside static method. With module level function, everything will look OK.

Cannot implicitly convert type from Task<>

The main issue with your example that you can't implicitly convert Task<T> return types to the base T type. You need to use the Task.Result property. Note that Task.Result will block async code, and should be used carefully.

Try this instead:

public List<int> TestGetMethod()  
{  
    return GetIdList().Result;  
}

How do I move to end of line in Vim?

Also note the distinction between line (or perhaps physical line) and screen line. A line is terminated by the End Of Line character ("\n"). A screen line is whatever happens to be shown as one row of characters in your terminal or in your screen. The two come apart if you have physical lines longer than the screen width, which is very common when writing emails and such.

The distinction shows up in the end-of-line commands as well.

  • $ and 0 move to the end or beginning of the physical line or paragraph, respectively:
  • g$ and g0 move to the end or beginning of the screen line or paragraph, respectively.

If you always prefer the latter behavior, you can remap the keys like this:

:noremap 0 g0
:noremap $ g$

Why am I getting "Received fatal alert: protocol_version" or "peer not authenticated" from Maven Central?

The following command helped me (executing on bash before running mvn)

export MAVEN_OPTS=-Dhttps.protocols=TLSv1,TLSv1.1,TLSv1.2