Programs & Examples On #Connectivity

Anything related to connectivity, i.e. the ability of systems to communicate with remote systems using some form of communication channel. Often used for questions on network connectivity.

java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/dbname

I had the same problem, my code is below:

private Connection conn = DriverManager.getConnection(Constant.MYSQL_URL, Constant.MYSQL_USER, Constant.MYSQL_PASSWORD);
private Statement stmt = conn.createStatement();

I have not loaded the driver class, but it works locally, I can query the results from MySQL, however, it does not work when I deploy it to Tomcat, and the errors below occur:

No suitable driver found for jdbc:mysql://172.16.41.54:3306/eduCloud

so I loaded the driver class, as below, when I saw other answers posted:

Class.forName("com.mysql.jdbc.Driver");

It works now! I don't know why it works well locally, I need your help, thank you so much!

Checking host availability by using ping in bash scripts

This is a complete bash script which pings target every 5 seconds and logs errors to a file.

Enjoy!

#!/bin/bash
        
        FILE=errors.txt
        TARGET=192.168.0.1

          touch $FILE
          while true;
          do
            DATE=$(date '+%d/%m/%Y %H:%M:%S')
            ping -c 1 $TARGET &> /dev/null
            if [[ $? -ne 0 ]]; then
              echo "ERROR "$DATE
              echo $DATE >> $FILE
            else
              echo "OK "$DATE
            fi
              sleep 5
          done

Simulate low network connectivity for Android

Do you want to test for no network connection, or just a slow network connection? If the former, you can go to Settings > Wireless & networks > Airplane mode and turn Airplane mode on. That will let you test network unavailability on an actual device.

Detect the Internet connection is offline?

You can determine that the connection is lost by making failed XHR requests.

The standard approach is to retry the request a few times. If it doesn't go through, alert the user to check the connection, and fail gracefully.

Sidenote: To put the entire application in an "offline" state may lead to a lot of error-prone work of handling state.. wireless connections may come and go, etc. So your best bet may be to just fail gracefully, preserve the data, and alert the user.. allowing them to eventually fix the connection problem if there is one, and to continue using your app with a fair amount of forgiveness.

Sidenote: You could check a reliable site like google for connectivity, but this may not be entirely useful as just trying to make your own request, because while Google may be available, your own application may not be, and you're still going to have to handle your own connection problem. Trying to send a ping to google would be a good way to confirm that the internet connection itself is down, so if that information is useful to you, then it might be worth the trouble.

Sidenote: Sending a Ping could be achieved in the same way that you would make any kind of two-way ajax request, but sending a ping to google, in this case, would pose some challenges. First, we'd have the same cross-domain issues that are typically encountered in making Ajax communications. One option is to set up a server-side proxy, wherein we actually ping google (or whatever site), and return the results of the ping to the app. This is a catch-22 because if the internet connection is actually the problem, we won't be able to get to the server, and if the connection problem is only on our own domain, we won't be able to tell the difference. Other cross-domain techniques could be tried, for example, embedding an iframe in your page which points to google.com, and then polling the iframe for success/failure (examine the contents, etc). Embedding an image may not really tell us anything, because we need a useful response from the communication mechanism in order to draw a good conclusion about what's going on. So again, determining the state of the internet connection as a whole may be more trouble than it's worth. You'll have to weight these options out for your specific app.

Android: Internet connectivity change listener

I have noticed that no one mentioned WorkManger solution which is better and support most of android devices.

You should have a Worker with network constraint AND it will fired only if network available, i.e:

val constraints = Constraints.Builder().setRequiredNetworkType(NetworkType.CONNECTED).build()
val worker = OneTimeWorkRequestBuilder<MyWorker>().setConstraints(constraints).build()

And in worker you do whatever you want once connection back, you may fire the worker periodically .

i.e:

inside dowork() callback:

notifierLiveData.postValue(info)

Detect network connection type on Android

On top of Emil's awsome answer I'd like to add one more method, for checking if you actually have Internet access as you could have data set to off on your phone.

public static boolean hasInternetAccess(Context c){
    TelephonyManager tm = (TelephonyManager) c.getSystemService(Context.TELEPHONY_SERVICE);
    if(isConnected(c) && tm.getDataState() == TelephonyManager.DATA_CONNECTED)
       return true;
    else
        return false;
}

Note that this is only for checking if theres a cellular data connection and will return false if you have WiFi connected, as the cellular data is off when WiFi is connected.

Update Item to Revision vs Revert to Revision

The files in your working copy might look exactly the same after, but they are still very different actions -- the repository is in a completely different state, and you will have different options available to you after reverting than "updating" to an old revision.

Briefly, "update to" only affects your working copy, but "reverse merge and commit" will affect the repository.

If you "update" to an old revision, then the repository has not changed: in your example, the HEAD revision is still 100. You don't have to commit anything, since you are just messing around with your working copy. If you make modifications to your working copy and try to commit, you will be told that your working copy is out-of-date, and you will need to update before you can commit. If someone else working on the same repository performs an "update", or if you check out a second working copy, it will be r100.

However, if you "reverse merge" to an old revision, then your working copy is still based on the HEAD (assuming you are up-to-date) -- but you are creating a new revision to supersede the unwanted changes. You have to commit these changes, since you are changing the repository. Once done, any updates or new working copies based on the HEAD will show r101, with the contents you just committed.

Bind TextBox on Enter-key press

Answered here quite elegantly using attached behaviors, my preferred method for almost anything.

WPF how to make textbox lose focus after hitting enter

How to enable scrolling of content inside a modal?

.modal-body {
    max-height: 80vh;
    overflow-y: scroll;
}

it's works for me

php search array key and get value

The key is already the ... ehm ... key

echo $array[20120504];

If you are unsure, if the key exists, test for it

$key = 20120504;
$result = isset($array[$key]) ? $array[$key] : null;

Minor addition:

$result = @$array[$key] ?: null;

One may argue, that @ is bad, but keep it serious: This is more readable and straight forward, isn't?

Update: With PHP7 my previous example is possible without the error-silencer

$result = $array[$key] ?? null;

Is Tomcat running?

Try this command

ps -ef | awk '/[t]omcat/{print $2}' 

It will return the pid if tomcat is running.

What is the path for the startup folder in windows 2008 server

SHGetKnownFolderPath:

Retrieves the full path of a known folder identified by the folder's KNOWNFOLDERID.

And, FOLDERID_CommonStartup:

Default Path %ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\StartUp

There are also managed equivalents, but you haven't told us what you're programming in.

ipython notebook clear cell output in code

You can use the IPython.display.clear_output to clear the output as mentioned in cel's answer. I would add that for me the best solution was to use this combination of parameters to print without any "shakiness" of the notebook:

from IPython.display import clear_output

for i in range(10):
    clear_output(wait=True)
    print(i, flush=True)

How to get current date & time in MySQL?

If you make change default value to CURRENT_TIMESTAMP it is more effiency,

ALTER TABLE servers MODIFY COLUMN network_shares datetime NOT NULL DEFAULT CURRENT_TIMESTAMP;

Return multiple values from a function, sub or type?

You might want want to rethink the structure of you application, if you really, really want one method to return multiple values.

Either break things apart, so distinct methods return distinct values, or figure out a logical grouping and build an object to hold that data that can in turn be returned.

' this is the VB6/VBA equivalent of a struct
' data, no methods
Private Type settings
    root As String
    path As String
    name_first As String
    name_last As String
    overwrite_prompt As Boolean
End Type


Public Sub Main()

    Dim mySettings As settings
    mySettings = getSettings()


End Sub

' if you want this to be public, you're better off with a class instead of a User-Defined-Type (UDT)
Private Function getSettings() As settings

    Dim sets As settings

    With sets ' retrieve values here
        .root = "foo"
        .path = "bar"
        .name_first = "Don"
        .name_last = "Knuth"
        .overwrite_prompt = False
    End With

    ' return a single struct, vb6/vba-style
    getSettings = sets

End Function

How to check if Location Services are enabled?

This is a very useful method that returns "true" if the Location services are enabled:

public static boolean locationServicesEnabled(Context context) {
        LocationManager lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
        boolean gps_enabled = false;
        boolean net_enabled = false;

        try {
            gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
        } catch (Exception ex) {
            Log.e(TAG,"Exception gps_enabled");
        }

        try {
            net_enabled = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
        } catch (Exception ex) {
            Log.e(TAG,"Exception network_enabled");
        }
        return gps_enabled || net_enabled;
}

exception in initializer error in java when using Netbeans

Retrofit have recently updated to 2.7.1 version. After that Android 4.x clients have crashed. See https://stackoverflow.com/a/60071876/2914140.

Downgrade Retrofit to 2.6.4.

Short circuit Array.forEach like calling break

Consider to use jquery's each method, since it allows to return false inside callback function:

$.each(function(e, i) { 
   if (i % 2) return false;
   console.log(e)
})

Lodash libraries also provides takeWhile method that can be chained with map/reduce/fold etc:

var users = [
  { 'user': 'barney',  'active': false },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': true }
];

_.takeWhile(users, function(o) { return !o.active; });
// => objects for ['barney', 'fred']

// The `_.matches` iteratee shorthand.
_.takeWhile(users, { 'user': 'barney', 'active': false });
// => objects for ['barney']

// The `_.matchesProperty` iteratee shorthand.
_.takeWhile(users, ['active', false]);
// => objects for ['barney', 'fred']

// The `_.property` iteratee shorthand.
_.takeWhile(users, 'active');
// => []

Rename MySQL database

If your DB contains only MyISAM tables (do not use this method if you have InnoDB tables):

  1. shut down the MySQL server
  2. go to the mysql data directory and rename the database directory (Note: non-alpha characters need to be encoded in a special way)
  3. restart the server
  4. adjust privileges if needed (grant access to the new DB name)

You can script it all in one command so that downtime is just a second or two.

What is the best way to redirect a page using React Router?

One of the simplest way: use Link as follows:

import { Link } from 'react-router-dom';

<Link to={`your-path`} activeClassName="current">{your-link-name}</Link>

If we want to cover the whole div section as link:

 <div>
     <Card as={Link} to={'path-name'}>
         .... 
           card content here
         ....
     </Card>
 </div>

Reset all the items in a form

Do as below create class and call it like this

Check : Reset all Controls (Textbox, ComboBox, CheckBox, ListBox) in a Windows Form using C#

private void button1_Click(object sender, EventArgs e)
{
   Utilities.ResetAllControls(this);
}

public class Utilities
    {
        public static void ResetAllControls(Control form)
        {
            foreach (Control control in form.Controls)
            {
                if (control is TextBox)
                {
                    TextBox textBox = (TextBox)control;
                    textBox.Text = null;
                }

                if (control is ComboBox)
                {
                    ComboBox comboBox = (ComboBox)control;
                    if (comboBox.Items.Count > 0)
                        comboBox.SelectedIndex = 0;
                }

                if (control is CheckBox)
                {
                    CheckBox checkBox = (CheckBox)control;
                    checkBox.Checked = false;
                }

                if (control is ListBox)
                {
                    ListBox listBox = (ListBox)control;
                    listBox.ClearSelected();
                }
            }
        }      
    }

How can I debug what is causing a connection refused or a connection time out?

The problem

The problem is in the network layer. Here are the status codes explained:

  • Connection refused: The peer is not listening on the respective network port you're trying to connect to. This usually means that either a firewall is actively denying the connection or the respective service is not started on the other site or is overloaded.

  • Connection timed out: During the attempt to establish the TCP connection, no response came from the other side within a given time limit. In the context of urllib this may also mean that the HTTP response did not arrive in time. This is sometimes also caused by firewalls, sometimes by network congestion or heavy load on the remote (or even local) site.

In context

That said, it is probably not a problem in your script, but on the remote site. If it's occuring occasionally, it indicates that the other site has load problems or the network path to the other site is unreliable.

Also, as it is a problem with the network, you cannot tell what happened on the other side. It is possible that the packets travel fine in the one direction but get dropped (or misrouted) in the other.

It is also not a (direct) DNS problem, that would cause another error (Name or service not known or something similar). It could however be the case that the DNS is configured to return different IP addresses on each request, which would connect you (DNS caching left aside) to different addresses hosts on each connection attempt. It could in turn be the case that some of these hosts are misconfigured or overloaded and thus cause the aforementioned problems.

Debugging this

As suggested in the another answer, using a packet analyzer can help to debug the issue. You won't see much however except the packets reflecting exactly what the error message says.

To rule out network congestion as a problem you could use a tool like mtr or traceroute or even ping to see if packets get lost to the remote site. Note that, if you see loss in mtr (and any traceroute tool for that matter), you must always consider the first host where loss occurs (in the route from yours to remote) as the one dropping packets, due to the way ICMP works. If the packets get lost only at the last hop over a long time (say, 100 packets), that host definetly has an issue. If you see that this behaviour is persistent (over several days), you might want to contact the administrator.

Loss in a middle of the route usually corresponds to network congestion (possibly due to maintenance), and there's nothing you could do about it (except whining at the ISP about missing redundance).

If network congestion is not a problem (i.e. not more than, say, 5% of the packets get lost), you should contact the remote server administrator to figure out what's wrong. He may be able to see relevant infos in system logs. Running a packet analyzer on the remote site might also be more revealing than on the local site. Checking whether the port is open using netstat -tlp is definetly recommended then.

What is the difference between a pandas Series and a single-column DataFrame?

Series is a one-dimensional labeled array capable of holding any data type (integers, strings, floating point numbers, Python objects, etc.). The axis labels are collectively referred to as the index. The basic method to create a Series is to call:

s = pd.Series(data, index=index)

DataFrame is a 2-dimensional labeled data structure with columns of potentially different types. You can think of it like a spreadsheet or SQL table, or a dict of Series objects.

 d = {'one' : pd.Series([1., 2., 3.], index=['a', 'b', 'c']),
 two' : pd.Series([1., 2., 3., 4.], index=['a', 'b', 'c', 'd'])}
 df = pd.DataFrame(d)

GC overhead limit exceeded

From Java SE 6 HotSpot[tm] Virtual Machine Garbage Collection Tuning

the following

Excessive GC Time and OutOfMemoryError

The concurrent collector will throw an OutOfMemoryError if too much time is being spent in garbage collection: if more than 98% of the total time is spent in garbage collection and less than 2% of the heap is recovered, an OutOfMemoryError will be thrown. This feature is designed to prevent applications from running for an extended period of time while making little or no progress because the heap is too small. If necessary, this feature can be disabled by adding the option -XX:-UseGCOverheadLimit to the command line.

The policy is the same as that in the parallel collector, except that time spent performing concurrent collections is not counted toward the 98% time limit. In other words, only collections performed while the application is stopped count toward excessive GC time. Such collections are typically due to a concurrent mode failure or an explicit collection request (e.g., a call to System.gc()).

in conjunction with a passage further down

One of the most commonly encountered uses of explicit garbage collection occurs with RMIs distributed garbage collection (DGC). Applications using RMI refer to objects in other virtual machines. Garbage cannot be collected in these distributed applications without occasionally collection the local heap, so RMI forces full collections periodically. The frequency of these collections can be controlled with properties. For example,

java -Dsun.rmi.dgc.client.gcInterval=3600000

-Dsun.rmi.dgc.server.gcInterval=3600000 specifies explicit collection once per hour instead of the default rate of once per minute. However, this may also cause some objects to take much longer to be reclaimed. These properties can be set as high as Long.MAX_VALUE to make the time between explicit collections effectively infinite, if there is no desire for an upper bound on the timeliness of DGC activity.

Seems to imply that the evaluation period for determining the 98% is one minute long, but it might be configurable on Sun's JVM with the correct define.

Of course, other interpretations are possible.

.NET / C# - Convert char[] to string

Use the string constructor which accepts chararray as argument, start position and length of array. Syntax is given below:

string charToString = new string(CharArray, 0, CharArray.Count());

How to use ConfigurationManager

Okay, it took me a while to see this, but there's no way this compiles:

return String.(ConfigurationManager.AppSettings[paramName]);

You're not even calling a method on the String type. Just do this:

return ConfigurationManager.AppSettings[paramName];

The AppSettings KeyValuePair already returns a string. If the name doesn't exist, it will return null.


Based on your edit you have not yet added a Reference to the System.Configuration assembly for the project you're working in.

How can I disable editing cells in a WPF Datagrid?

If you want to disable editing the entire grid, you can set IsReadOnly to true on the grid. If you want to disable user to add new rows, you set the property CanUserAddRows="False"

<DataGrid IsReadOnly="True" CanUserAddRows="False" />

Further more you can set IsReadOnly on individual columns to disable editing.

error: function returns address of local variable

All the answer explain the problem really good.

However, I would like to add another information.

I faced the same problem at the moment I wanted the output of a function to be a vector.

In this situation, the common solution is to declare the output as an argument of the function itself. This way, the alloc of the variable and the physical space necessary to store the information are managed outside the function. Pseudocode to explain the classical solution is:

void function(int input, int* output){
    //...
    output[0] = something;
    output[1] = somethig_else;
    //...
    return;
}

In this case, the example code within the question should be changed in:

void foo(int x, char* a){
     if(x < 0){
        char b = "blah";
        //...
        strcpy(a, b);
        //..
        return;
      }
    //..
}

Determine when a ViewPager changes pages

You can also use ViewPager.SimpleOnPageChangeListener instead of ViewPager.OnPageChangeListener and override only those methods you want to use.

viewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {

    // optional 
    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { }

    // optional 
    @Override
    public void onPageSelected(int position) { }

    // optional 
    @Override
    public void onPageScrollStateChanged(int state) { }
});

Hope this help :)

Edit: As per android APIs, setOnPageChangeListener (ViewPager.OnPageChangeListener listener) is deprecated. Please check this url:- Android ViewPager API

Cross-thread operation not valid: Control 'textBox1' accessed from a thread other than the thread it was created on

Along the same lines as previous answers, but a very short addition that Allows to use all Control properties without having cross thread invokation exception.

Helper Method

    /// <summary>
    /// Helper method to determin if invoke required, if so will rerun method on correct thread.
    /// if not do nothing.
    /// </summary>
    /// <param name="c">Control that might require invoking</param>
    /// <param name="a">action to preform on control thread if so.</param>
    /// <returns>true if invoke required</returns>
    public bool ControlInvokeRequired(Control c,Action a)
    {
        if (c.InvokeRequired) c.Invoke(new MethodInvoker(delegate { a(); }));
        else return false;

        return true;
    }

Sample Usage

    // usage on textbox
    public void UpdateTextBox1(String text)
    {
        //Check if invoke requied if so return - as i will be recalled in correct thread
        if (ControlInvokeRequired(textBox1, () => UpdateTextBox1(text))) return;
        textBox1.Text = ellapsed;
    }

    //Or any control
    public void UpdateControl(Color c,String s)
    {
        //Check if invoke requied if so return - as i will be recalled in correct thread
        if (ControlInvokeRequired(myControl, () => UpdateControl(c,s))) return;
        myControl.Text = s;
        myControl.BackColor = c;
    }

Getters \ setters for dummies

You'd use them for instance to implement computed properties.

For example:

function Circle(radius) {
    this.radius = radius;
}

Object.defineProperty(Circle.prototype, 'circumference', {
    get: function() { return 2*Math.PI*this.radius; }
});

Object.defineProperty(Circle.prototype, 'area', {
    get: function() { return Math.PI*this.radius*this.radius; }
});

c = new Circle(10);
console.log(c.area); // Should output 314.159
console.log(c.circumference); // Should output 62.832

(CodePen)

Using "-Filter" with a variable

You don't need quotes around the variable, so simply change this:

Get-ADComputer -Filter {name -like '$nameregex' -and Enabled -eq "true"}

into this:

Get-ADComputer -Filter {name -like $nameregex -and Enabled -eq "true"}

Note, however, that the scriptblock notation for filter statements is misleading, because the statement is actually a string, so it's better to write it as such:

Get-ADComputer -Filter "name -like '$nameregex' -and Enabled -eq 'true'"

Related. Also related.

And FTR: you're using wildcard matching here (operator -like), not regular expressions (operator -match).

Get the position of a spinner in Android

The way to get the selection of the spinner is:

  spinner1.getSelectedItemPosition();

Documentation reference: http://developer.android.com/reference/android/widget/AdapterView.html#getSelectedItemPosition()

However, in your code, the one place you are referencing it is within your setOnItemSelectedListener(). It is not necessary to poll the spinner, because the onItemSelected method gets passed the position as the "position" variable.

So you could change that line to:

TestProjectActivity.this.number = position + 1;

If that does not fix the problem, please post the error message generated when your app crashes.

How to start mongodb shell?

In the terminal, use "mongo" command to switch the terminal into the MongoDB shell:

$ mongo
MongoDB shell version: 2.6.10
connecting to: admin
>

Once you get > symbol in the terminal, you have entered into the MongoDB shell.

Python string class like StringBuilder in C#?

There is no one-to-one correlation. For a really good article please see Efficient String Concatenation in Python:

Building long strings in the Python progamming language can sometimes result in very slow running code. In this article I investigate the computational performance of various string concatenation methods.

Inserting into Oracle and retrieving the generated sequence ID

Expanding a bit on the answers from @Guru and @Ronnis, you can hide the sequence and make it look more like an auto-increment using a trigger, and have a procedure that does the insert for you and returns the generated ID as an out parameter.

create table batch(batchid number,
    batchname varchar2(30),
    batchtype char(1),
    source char(1),
    intarea number)
/

create sequence batch_seq start with 1
/

create trigger batch_bi
before insert on batch
for each row
begin
    select batch_seq.nextval into :new.batchid from dual;
end;
/

create procedure insert_batch(v_batchname batch.batchname%TYPE,
    v_batchtype batch.batchtype%TYPE,
    v_source batch.source%TYPE,
    v_intarea batch.intarea%TYPE,
    v_batchid out batch.batchid%TYPE)
as
begin
    insert into batch(batchname, batchtype, source, intarea)
    values(v_batchname, v_batchtype, v_source, v_intarea)
    returning batchid into v_batchid;
end;
/

You can then call the procedure instead of doing a plain insert, e.g. from an anoymous block:

declare
    l_batchid batch.batchid%TYPE;
begin
    insert_batch(v_batchname => 'Batch 1',
        v_batchtype => 'A',
        v_source => 'Z',
        v_intarea => 1,
        v_batchid => l_batchid);
    dbms_output.put_line('Generated id: ' || l_batchid);

    insert_batch(v_batchname => 'Batch 99',
        v_batchtype => 'B',
        v_source => 'Y',
        v_intarea => 9,
        v_batchid => l_batchid);
    dbms_output.put_line('Generated id: ' || l_batchid);
end;
/

Generated id: 1
Generated id: 2

You can make the call without an explicit anonymous block, e.g. from SQL*Plus:

variable l_batchid number;
exec insert_batch('Batch 21', 'C', 'X', 7, :l_batchid);

... and use the bind variable :l_batchid to refer to the generated value afterwards:

print l_batchid;
insert into some_table values(:l_batch_id, ...);

Using SUMIFS with multiple AND OR conditions

Speed

SUMPRODUCT is faster than SUM arrays, i.e. having {} arrays in the SUM function. SUMIFS is 30% faster than SUMPRODUCT.

{SUM(SUMIFS({}))} vs SUMPRODUCT(SUMIFS({})) both works fine, but SUMPRODUCT feels a bit easier to write without the CTRL-SHIFT-ENTER to create the {}.

Preference

I personally prefer writing SUMPRODUCT(--(ISNUMBER(MATCH(...)))) over SUMPRODUCT(SUMIFS({})) for multiple criteria.

However, if you have a drop-down menu where you want to select specific characteristics or all, SUMPRODUCT(SUMIFS()), is the only way to go. (as for selecting "all", the value should enter in "<>" + "Whatever word you want as long as it's not part of the specific characteristics".

Linking a UNC / Network drive on an html page

Setup IIS on the network server and change the path to http://server/path/to/file.txt

EDIT: Make sure you enable directory browsing in IIS

How can I sharpen an image in OpenCV?

You can try a simple kernel and the filter2D function, e.g. in Python:

kernel = np.array([[-1,-1,-1], [-1,9,-1], [-1,-1,-1]])
im = cv2.filter2D(im, -1, kernel)

Wikipedia has a good overview of kernels with some more examples here - https://en.wikipedia.org/wiki/Kernel_(image_processing)

In image processing, a kernel, convolution matrix, or mask is a small matrix. It is used for blurring, sharpening, embossing, edge detection, and more. This is accomplished by doing a convolution between a kernel and an image.

How does Git handle symbolic links?

You can find out what Git does with a file by seeing what it does when you add it to the index. The index is like a pre-commit. With the index committed, you can use git checkout to bring everything that was in the index back into the working directory. So, what does Git do when you add a symbolic link to the index?

To find out, first, make a symbolic link:

$ ln -s /path/referenced/by/symlink symlink

Git doesn't know about this file yet. git ls-files lets you inspect your index (-s prints stat-like output):

$ git ls-files -s ./symlink
[nothing]

Now, add the contents of the symbolic link to the Git object store by adding it to the index. When you add a file to the index, Git stores its contents in the Git object store.

$ git add ./symlink

So, what was added?

$ git ls-files -s ./symlink
120000 1596f9db1b9610f238b78dd168ae33faa2dec15c 0       symlink

The hash is a reference to the packed object that was created in the Git object store. You can examine this object if you look in .git/objects/15/96f9db1b9610f238b78dd168ae33faa2dec15c in the root of your repository. This is the file that Git stores in the repository, that you can later check out. If you examine this file, you'll see it is very small. It does not store the contents of the linked file. To confirm this, print the contents of the packed repository object with git cat-file:

$ git cat-file -p 1596f9db1b9610f238b78dd168ae33faa2dec15c
/path/referenced/by/symlink

(Note 120000 is the mode listed in ls-files output. It would be something like 100644 for a regular file.)

But what does Git do with this object when you check it out from the repository and into your filesystem? It depends on the core.symlinks config. From man git-config:

core.symlinks

If false, symbolic links are checked out as small plain files that contain the link text.

So, with a symbolic link in the repository, upon checkout you either get a text file with a reference to a full filesystem path, or a proper symbolic link, depending on the value of the core.symlinks config.

Either way, the data referenced by the symlink is not stored in the repository.

finding and replacing elements in a list

a = [1,2,3,4,5,1,2,3,4,5,1,12]
for i in range (len(a)):
    if a[i]==2:
        a[i]=123

You can use a for and or while loop; however if u know the builtin Enumerate function, then it is recommended to use Enumerate.1

Parsing JSON in Excel VBA

Lots of good answers here - just chipping in my own.

I had a requirement to parse a very specific JSON string, representing the results of making a web-API call. The JSON described a list of objects, and looked something like this:

[
   {
     "property1": "foo",
     "property2": "bar",
     "timeOfDay": "2019-09-30T00:00:00",
     "numberOfHits": 98,
     "isSpecial": false,
     "comment": "just to be awkward, this contains a comma"
   },
   {
     "property1": "fool",
     "property2": "barrel",
     "timeOfDay": "2019-10-31T00:00:00",
     "numberOfHits": 11,
     "isSpecial": false,
     "comment": null
   },
   ...
]

There are a few things to note about this:

  1. The JSON should always describe a list (even if empty), which should only contain objects.
  2. The objects in the list should only contain properties with simple types (string / date / number / boolean or null).
  3. The value of a property may contain a comma - which makes parsing the JSON somewhat harder - but may not contain any quotes (because I'm too lazy to deal with that).

The ParseListOfObjects function in the code below takes the JSON string as input, and returns a Collection representing the items in the list. Each item is represented as a Dictionary, where the keys of the dictionary correspond to the names of the object's properties. The values are automatically converted to the appropriate type (String, Date, Double, Boolean - or Empty if the value is null).

Your VBA project will need a reference to the Microsoft Scripting Runtime library to use the Dictionary object - though it would not be difficult to remove this dependency if you use a different way of encoding the results.

Here's my JSON.bas:

Option Explicit

' NOTE: a fully-featured JSON parser in VBA would be a beast.
' This simple parser only supports VERY simple JSON (which is all we need).
' Specifically, it supports JSON comprising a list of objects, each of which has only simple properties.

Private Const strSTART_OF_LIST As String = "["
Private Const strEND_OF_LIST As String = "]"

Private Const strLIST_DELIMITER As String = ","

Private Const strSTART_OF_OBJECT As String = "{"
Private Const strEND_OF_OBJECT As String = "}"

Private Const strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR As String = ":"

Private Const strQUOTE As String = """"

Private Const strNULL_VALUE As String = "null"
Private Const strTRUE_VALUE As String = "true"
Private Const strFALSE_VALUE As String = "false"


Public Function ParseListOfObjects(ByVal strJson As String) As Collection

    ' Takes a JSON string that represents a list of objects (where each object has only simple value properties), and
    ' returns a collection of dictionary objects, where the keys and values of each dictionary represent the names and
    ' values of the JSON object properties.

    Set ParseListOfObjects = New Collection

    Dim strList As String: strList = Trim(strJson)

    ' Check we have a list
    If Left(strList, Len(strSTART_OF_LIST)) <> strSTART_OF_LIST _
    Or Right(strList, Len(strEND_OF_LIST)) <> strEND_OF_LIST Then
        Err.Raise vbObjectError, Description:="The provided JSON does not appear to be a list (it does not start with '" & strSTART_OF_LIST & "' and end with '" & strEND_OF_LIST & "')"
    End If

    ' Get the list item text (between the [ and ])
    Dim strBody As String: strBody = Trim(Mid(strList, 1 + Len(strSTART_OF_LIST), Len(strList) - Len(strSTART_OF_LIST) - Len(strEND_OF_LIST)))

    If strBody = "" Then
        Exit Function
    End If

    ' Check we have a list of objects
    If Left(strBody, Len(strSTART_OF_OBJECT)) <> strSTART_OF_OBJECT Then
        Err.Raise vbObjectError, Description:="The provided JSON does not appear to be a list of objects (the content of the list does not start with '" & strSTART_OF_OBJECT & "')"
    End If

    ' We now have something like:
    '    {"property":"value", "property":"value"}, {"property":"value", "property":"value"}, ...
    ' so we can't just split on a comma to get the various items (because the items themselves have commas in them).
    ' HOWEVER, since we know we're dealing with very simple JSON that has no nested objects, we can split on "}," because
    ' that should only appear between items. That'll mean that all but the last item will be missing it's closing brace.
    Dim astrItems() As String: astrItems = Split(strBody, strEND_OF_OBJECT & strLIST_DELIMITER)

    Dim ixItem As Long
    For ixItem = LBound(astrItems) To UBound(astrItems)

        Dim strItem As String: strItem = Trim(astrItems(ixItem))

        If Left(strItem, Len(strSTART_OF_OBJECT)) <> strSTART_OF_OBJECT Then
            Err.Raise vbObjectError, Description:="Mal-formed list item (does not start with '" & strSTART_OF_OBJECT & "')"
        End If

        ' Only the last item will have a closing brace (see comment above)
        Dim bIsLastItem As Boolean: bIsLastItem = ixItem = UBound(astrItems)

        If bIsLastItem Then
            If Right(strItem, Len(strEND_OF_OBJECT)) <> strEND_OF_OBJECT Then
                Err.Raise vbObjectError, Description:="Mal-formed list item (does not end with '" & strEND_OF_OBJECT & "')"
            End If
        End If

        Dim strContent: strContent = Mid(strItem, 1 + Len(strSTART_OF_OBJECT), Len(strItem) - Len(strSTART_OF_OBJECT) - IIf(bIsLastItem, Len(strEND_OF_OBJECT), 0))

        ParseListOfObjects.Add ParseObjectContent(strContent)

    Next ixItem

End Function

Private Function ParseObjectContent(ByVal strContent As String) As Scripting.Dictionary

    Set ParseObjectContent = New Scripting.Dictionary
    ParseObjectContent.CompareMode = TextCompare

    ' The object content will look something like:
    '    "property":"value", "property":"value", ...
    ' ... although the value may not be in quotes, since numbers are not quoted.
    ' We can't assume that the property value won't contain a comma, so we can't just split the
    ' string on the commas, but it's reasonably safe to assume that the value won't contain further quotes
    ' (and we're already assuming no sub-structure).
    ' We'll need to scan for commas while taking quoted strings into account.

    Dim ixPos As Long: ixPos = 1
    Do While ixPos <= Len(strContent)

        Dim strRemainder As String

        ' Find the opening quote for the name (names should always be quoted)
        Dim ixOpeningQuote As Long: ixOpeningQuote = InStr(ixPos, strContent, strQUOTE)

        If ixOpeningQuote <= 0 Then
            ' The only valid reason for not finding a quote is if we're at the end (though white space is permitted)
            strRemainder = Trim(Mid(strContent, ixPos))
            If Len(strRemainder) = 0 Then
                Exit Do
            End If
            Err.Raise vbObjectError, Description:="Mal-formed object (the object name does not start with a quote)"
        End If

        ' Now find the closing quote for the name, which we assume is the very next quote
        Dim ixClosingQuote As Long: ixClosingQuote = InStr(ixOpeningQuote + 1, strContent, strQUOTE)
        If ixClosingQuote <= 0 Then
            Err.Raise vbObjectError, Description:="Mal-formed object (the object name does not end with a quote)"
        End If

        If ixClosingQuote - ixOpeningQuote - Len(strQUOTE) = 0 Then
            Err.Raise vbObjectError, Description:="Mal-formed object (the object name is blank)"
        End If

        Dim strName: strName = Mid(strContent, ixOpeningQuote + Len(strQUOTE), ixClosingQuote - ixOpeningQuote - Len(strQUOTE))

        ' The next thing after the quote should be the colon

        Dim ixNameValueSeparator As Long: ixNameValueSeparator = InStr(ixClosingQuote + Len(strQUOTE), strContent, strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR)

        If ixNameValueSeparator <= 0 Then
            Err.Raise vbObjectError, Description:="Mal-formed object (missing '" & strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR & "')"
        End If

        ' Check that there was nothing between the closing quote and the colon

        strRemainder = Trim(Mid(strContent, ixClosingQuote + Len(strQUOTE), ixNameValueSeparator - ixClosingQuote - Len(strQUOTE)))
        If Len(strRemainder) > 0 Then
            Err.Raise vbObjectError, Description:="Mal-formed object (unexpected content between name and '" & strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR & "')"
        End If

        ' What comes after the colon is the value, which may or may not be quoted (e.g. numbers are not quoted).
        ' If the very next thing we see is a quote, then it's a quoted value, and we need to find the matching
        ' closing quote while ignoring any commas inside the quoted value.
        ' If the next thing we see is NOT a quote, then it must be an unquoted value, and we can scan directly
        ' for the next comma.
        ' Either way, we're looking for a quote or a comma, whichever comes first (or neither, in which case we
        ' have the last - unquoted - value).

        ixOpeningQuote = InStr(ixNameValueSeparator + Len(strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR), strContent, strQUOTE)
        Dim ixPropertySeparator As Long: ixPropertySeparator = InStr(ixNameValueSeparator + Len(strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR), strContent, strLIST_DELIMITER)

        If ixOpeningQuote > 0 And ixPropertySeparator > 0 Then
            ' Only use whichever came first
            If ixOpeningQuote < ixPropertySeparator Then
                ixPropertySeparator = 0
            Else
                ixOpeningQuote = 0
            End If
        End If

        Dim strValue As String
        Dim vValue As Variant

        If ixOpeningQuote <= 0 Then ' it's not a quoted value

            If ixPropertySeparator <= 0 Then ' there's no next value; this is the last one
                strValue = Trim(Mid(strContent, ixNameValueSeparator + Len(strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR)))
                ixPos = Len(strContent) + 1
            Else ' this is not the last value
                strValue = Trim(Mid(strContent, ixNameValueSeparator + Len(strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR), ixPropertySeparator - ixNameValueSeparator - Len(strOBJECT_PROPERTY_NAME_VALUE_SEPARATOR)))
                ixPos = ixPropertySeparator + Len(strLIST_DELIMITER)
            End If

            vValue = ParseUnquotedValue(strValue)

        Else ' It is a quoted value

            ' Find the corresponding closing quote, which should be the very next one

            ixClosingQuote = InStr(ixOpeningQuote + Len(strQUOTE), strContent, strQUOTE)

            If ixClosingQuote <= 0 Then
                Err.Raise vbObjectError, Description:="Mal-formed object (the value does not end with a quote)"
            End If

            strValue = Mid(strContent, ixOpeningQuote + Len(strQUOTE), ixClosingQuote - ixOpeningQuote - Len(strQUOTE))
            vValue = ParseQuotedValue(strValue)

            ' Re-scan for the property separator, in case we hit one that was part of the quoted value
            ixPropertySeparator = InStr(ixClosingQuote + Len(strQUOTE), strContent, strLIST_DELIMITER)

            If ixPropertySeparator <= 0 Then ' this was the last value

                ' Check that there's nothing between the closing quote and the end of the text
                strRemainder = Trim(Mid(strContent, ixClosingQuote + Len(strQUOTE)))
                If Len(strRemainder) > 0 Then
                    Err.Raise vbObjectError, Description:="Mal-formed object (there is content after the last value)"
                End If

                ixPos = Len(strContent) + 1

            Else ' this is not the last value

                ' Check that there's nothing between the closing quote and the property separator
                strRemainder = Trim(Mid(strContent, ixClosingQuote + Len(strQUOTE), ixPropertySeparator - ixClosingQuote - Len(strQUOTE)))
                If Len(strRemainder) > 0 Then
                    Err.Raise vbObjectError, Description:="Mal-formed object (there is content after the last value)"
                End If

                ixPos = ixPropertySeparator + Len(strLIST_DELIMITER)

            End If

        End If

        ParseObjectContent.Add strName, vValue

    Loop

End Function

Private Function ParseUnquotedValue(ByVal strValue As String) As Variant

    If StrComp(strValue, strNULL_VALUE, vbTextCompare) = 0 Then
        ParseUnquotedValue = Empty
    ElseIf StrComp(strValue, strTRUE_VALUE, vbTextCompare) = 0 Then
        ParseUnquotedValue = True
    ElseIf StrComp(strValue, strFALSE_VALUE, vbTextCompare) = 0 Then
        ParseUnquotedValue = False
    ElseIf IsNumeric(strValue) Then
        ParseUnquotedValue = CDbl(strValue)
    Else
        Err.Raise vbObjectError, Description:="Mal-formed value (not null, true, false or a number)"
    End If

End Function

Private Function ParseQuotedValue(ByVal strValue As String) As Variant

    ' Both dates and strings are quoted; we'll treat it as a date if it has the expected date format.
    ' Dates are in the form:
    '    2019-09-30T00:00:00
    If strValue Like "####-##-##T##:00:00" Then
        ' NOTE: we just want the date part
        ParseQuotedValue = CDate(Left(strValue, Len("####-##-##")))
    Else
        ParseQuotedValue = strValue
    End If

End Function

A simple test:

Const strJSON As String = "[{""property1"":""foo""}]"
Dim oObjects As Collection: Set oObjects = Json.ParseListOfObjects(strJSON)

MsgBox oObjects(1)("property1") ' shows "foo"

Evaluating string "3*(4+2)" yield int 18

Try this:

static double Evaluate(string expression) {
  var loDataTable = new DataTable();
  var loDataColumn = new DataColumn("Eval", typeof (double), expression);
  loDataTable.Columns.Add(loDataColumn);
  loDataTable.Rows.Add(0);
  return (double) (loDataTable.Rows[0]["Eval"]);
}

How can I pull from remote Git repository and override the changes in my local repository?

Provided that the remote repository is origin, and that you're interested in master:

git fetch origin
git reset --hard origin/master

This tells it to fetch the commits from the remote repository, and position your working copy to the tip of its master branch.

All your local commits not common to the remote will be gone.

What is mapDispatchToProps?

mapStateToProps() is a utility which helps your component get updated state(which is updated by some other components),
mapDispatchToProps() is a utility which will help your component to fire an action event (dispatching action which may cause change of application state)

How long will my session last?

This is the one. The session will last for 1440 seconds (24 minutes).

session.gc_maxlifetime  1440    1440

Rails 4 LIKE query - ActiveRecord adds quotes

While string interpolation will work, as your question specifies rails 4, you could be using Arel for this and keeping your app database agnostic.

def self.search(query, page=1)
  query = "%#{query}%"
  name_match = arel_table[:name].matches(query)
  postal_match = arel_table[:postal_code].matches(query)
  where(name_match.or(postal_match)).page(page).per_page(5)
end

RSA Public Key format

Starting from the decoded base64 data of an OpenSSL rsa-ssh Key, i've been able to guess a format:

  • 00 00 00 07: four byte length prefix (7 bytes)
  • 73 73 68 2d 72 73 61: "ssh-rsa"
  • 00 00 00 01: four byte length prefix (1 byte)
  • 25: RSA Exponent (e): 25
  • 00 00 01 00: four byte length prefix (256 bytes)
  • RSA Modulus (n):

    7f 9c 09 8e 8d 39 9e cc d5 03 29 8b c4 78 84 5f
    d9 89 f0 33 df ee 50 6d 5d d0 16 2c 73 cf ed 46 
    dc 7e 44 68 bb 37 69 54 6e 9e f6 f0 c5 c6 c1 d9 
    cb f6 87 78 70 8b 73 93 2f f3 55 d2 d9 13 67 32 
    70 e6 b5 f3 10 4a f5 c3 96 99 c2 92 d0 0f 05 60 
    1c 44 41 62 7f ab d6 15 52 06 5b 14 a7 d8 19 a1 
    90 c6 c1 11 f8 0d 30 fd f5 fc 00 bb a4 ef c9 2d 
    3f 7d 4a eb d2 dc 42 0c 48 b2 5e eb 37 3c 6c a0 
    e4 0a 27 f0 88 c4 e1 8c 33 17 33 61 38 84 a0 bb 
    d0 85 aa 45 40 cb 37 14 bf 7a 76 27 4a af f4 1b 
    ad f0 75 59 3e ac df cd fc 48 46 97 7e 06 6f 2d 
    e7 f5 60 1d b1 99 f8 5b 4f d3 97 14 4d c5 5e f8 
    76 50 f0 5f 37 e7 df 13 b8 a2 6b 24 1f ff 65 d1 
    fb c8 f8 37 86 d6 df 40 e2 3e d3 90 2c 65 2b 1f 
    5c b9 5f fa e9 35 93 65 59 6d be 8c 62 31 a9 9b 
    60 5a 0e e5 4f 2d e6 5f 2e 71 f3 7e 92 8f fe 8b
    

The closest validation of my theory i can find it from RFC 4253:

The "ssh-rsa" key format has the following specific encoding:

  string    "ssh-rsa"
  mpint     e
  mpint     n

Here the 'e' and 'n' parameters form the signature key blob.

But it doesn't explain the length prefixes.


Taking the random RSA PUBLIC KEY i found (in the question), and decoding the base64 into hex:

30 82 01 0a 02 82 01 01 00 fb 11 99 ff 07 33 f6 e8 05 a4 fd 3b 36 ca 68 
e9 4d 7b 97 46 21 16 21 69 c7 15 38 a5 39 37 2e 27 f3 f5 1d f3 b0 8b 2e 
11 1c 2d 6b bf 9f 58 87 f1 3a 8d b4 f1 eb 6d fe 38 6c 92 25 68 75 21 2d 
dd 00 46 87 85 c1 8a 9c 96 a2 92 b0 67 dd c7 1d a0 d5 64 00 0b 8b fd 80 
fb 14 c1 b5 67 44 a3 b5 c6 52 e8 ca 0e f0 b6 fd a6 4a ba 47 e3 a4 e8 94 
23 c0 21 2c 07 e3 9a 57 03 fd 46 75 40 f8 74 98 7b 20 95 13 42 9a 90 b0 
9b 04 97 03 d5 4d 9a 1c fe 3e 20 7e 0e 69 78 59 69 ca 5b f5 47 a3 6b a3 
4d 7c 6a ef e7 9f 31 4e 07 d9 f9 f2 dd 27 b7 29 83 ac 14 f1 46 67 54 cd 
41 26 25 16 e4 a1 5a b1 cf b6 22 e6 51 d3 e8 3f a0 95 da 63 0b d6 d9 3e 
97 b0 c8 22 a5 eb 42 12 d4 28 30 02 78 ce 6b a0 cc 74 90 b8 54 58 1f 0f 
fb 4b a3 d4 23 65 34 de 09 45 99 42 ef 11 5f aa 23 1b 15 15 3d 67 83 7a 
63 02 03 01 00 01

From RFC3447 - Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1:

A.1.1 RSA public key syntax

An RSA public key should be represented with the ASN.1 type RSAPublicKey:

  RSAPublicKey ::= SEQUENCE {
     modulus           INTEGER,  -- n
     publicExponent    INTEGER   -- e
  }

The fields of type RSAPublicKey have the following meanings:

  • modulus is the RSA modulus n.
  • publicExponent is the RSA public exponent e.

Using Microsoft's excellent (and the only real) ASN.1 documentation:

30 82 01 0a       ;SEQUENCE (0x010A bytes: 266 bytes)
|  02 82 01 01    ;INTEGER  (0x0101 bytes: 257 bytes)
|  |  00          ;leading zero because high-bit, but number is positive
|  |  fb 11 99 ff 07 33 f6 e8 05 a4 fd 3b 36 ca 68 
|  |  e9 4d 7b 97 46 21 16 21 69 c7 15 38 a5 39 37 2e 27 f3 f5 1d f3 b0 8b 2e 
|  |  11 1c 2d 6b bf 9f 58 87 f1 3a 8d b4 f1 eb 6d fe 38 6c 92 25 68 75 21 2d 
|  |  dd 00 46 87 85 c1 8a 9c 96 a2 92 b0 67 dd c7 1d a0 d5 64 00 0b 8b fd 80 
|  |  fb 14 c1 b5 67 44 a3 b5 c6 52 e8 ca 0e f0 b6 fd a6 4a ba 47 e3 a4 e8 94 
|  |  23 c0 21 2c 07 e3 9a 57 03 fd 46 75 40 f8 74 98 7b 20 95 13 42 9a 90 b0 
|  |  9b 04 97 03 d5 4d 9a 1c fe 3e 20 7e 0e 69 78 59 69 ca 5b f5 47 a3 6b a3 
|  |  4d 7c 6a ef e7 9f 31 4e 07 d9 f9 f2 dd 27 b7 29 83 ac 14 f1 46 67 54 cd 
|  |  41 26 25 16 e4 a1 5a b1 cf b6 22 e6 51 d3 e8 3f a0 95 da 63 0b d6 d9 3e 
|  |  97 b0 c8 22 a5 eb 42 12 d4 28 30 02 78 ce 6b a0 cc 74 90 b8 54 58 1f 0f 
|  |  fb 4b a3 d4 23 65 34 de 09 45 99 42 ef 11 5f aa 23 1b 15 15 3d 67 83 7a 
|  |  63 
|  02 03          ;INTEGER (3 bytes)
|     01 00 01

giving the public key modulus and exponent:

  • modulus = 0xfb1199ff0733f6e805a4fd3b36ca68...837a63
  • exponent = 65,537

Update: My expanded form of this answer in another question

Difference between datetime and timestamp in sqlserver?

According to the documentation, timestamp is a synonym for rowversion - it's automatically generated and guaranteed1 to be unique. datetime isn't - it's just a data type which handles dates and times, and can be client-specified on insert etc.


1 Assuming you use it properly, of course. See comments.

How to get image size (height & width) using JavaScript?

JQuery Answer:

$height = $('#image_id').height();
$width  = $('#image_id').width();

Vue.js data-bind style backgroundImage not working

Based on my knowledge, if you put your image folder in your public folder, you can just do the following:

   <div :style="{backgroundImage: `url(${project.imagePath})`}"></div>

If you put your images in the src/assets/, you need to use require. Like this:

   <div :style="{backgroundImage: 'url('+require('@/assets/'+project.image)+')'}">. 
   </div>

One important thing is that you cannot use an expression that contains the full URL like this project.image = '@/assets/image.png'. You need to hardcode the '@assets/' part. That was what I've found. I think the reason is that in Webpack, a context is created if your require contains expressions, so the exact module is not known on compile time. Instead, it will search for everything in the @/assets folder. More info could be found here. Here is another doc explains how the Vue loader treats the link in single file components.

Eclipse CDT: no rule to make target all

If the above solutions did not work for you so -

Could be that you did not install C++ compiler packages properly, flow this: (Instructions for Win7, 32bit/64bit)

  1. Make sure you install properly one or more of the supporting C++ compiler packages:

    (I installed MinGW (HowTo Install Videos can be found on YouTube))

    In case you choose to install MinGW packages:

    • Download MinGW installer from the Install Page above
    • Run MinGW installer and make sure to choose the following packages:

      - mingw-developer-toolkit
      - mingw32-base
      - mingw32-gcc-g++
      - msys-base

    • Add MinGW and MSYS bin paths to your PATH environment variable , if you didn't change the default installation folders you should add:

    C:\MinGW\msys\1.0\bin;C:\MinGW\bin;
    • Logoff and log back in for making sure Environment vars kicked in
  2. Create a new C++ project in eclipse:

    • New -> C++ Projects
    • Choose Project type: Executables -> Hello World C++ project
      (Now on the right, under Toolchains you shall see MinGW GCC)
    • Select MinGW GCC from the Toolchains list
    • Hit Finish
  3. In you Hello World Project you shall see + src folder, and + Includes (If so you are probably good to go).

  4. Build project
  5. Run it!

Unable to find a @SpringBootConfiguration when doing a JpaTest

This is more the the error itself, not answering the original question:

We were migrating from java 8 to java 11. Application compiled successfully, but the errors Unable to find a @SpringBootConfiguration started to appear in the integration tests when ran from command line using maven (from IntelliJ it worked).

It appeared that maven-failsafe-plugin stopped seeing the classes on classpath, we fixed that by telling failsafe plugin to include the classes manually:

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-failsafe-plugin</artifactId>
            <configuration>
                <additionalClasspathElements>
                    <additionalClasspathElement>${basedir}/target/classes</additionalClasspathElement>
                </additionalClasspathElements>
            </configuration>
            ...
        </plugin>

codeigniter model error: Undefined property

You have to load the db library first. In autoload.php add :

$autoload['libraries'] = array('database');

Also, try renaming User model class for "User_model".

How do I setup the InternetExplorerDriver so it works

Unpack it and place somewhere you can find it. In my example, I will assume you will place it to C:\Selenium\iexploredriver.exe

Then you have to set it up in the system. Here is the Java code pasted from my Selenium project:

File file = new File("C:/Selenium/iexploredriver.exe");
System.setProperty("webdriver.ie.driver", file.getAbsolutePath());
WebDriver driver = new InternetExplorerDriver();

Basically, you have to set this property before you initialize driver

Reference:

How can I force a long string without any blank to be wrapped?

Use a CSS method to force wrap a string that has no white-spaces. Three methods:

1) Use the CSS white-space property. To cover browser inconsistencies, you have to declare it several ways. So just put your looooong string into some block level element (e.g., div, pre, p) and give that element the following css:

some_block_level_tag {
    white-space: pre;           /* CSS 2.0 */
    white-space: pre-wrap;      /* CSS 2.1 */
    white-space: pre-line;      /* CSS 3.0 */
    white-space: -pre-wrap;     /* Opera 4-6 */
    white-space: -o-pre-wrap;   /* Opera 7 */
    white-space: -moz-pre-wrap; /* Mozilla */
    white-space: -hp-pre-wrap;  /* HP Printers */
    word-wrap: break-word;      /* IE 5+ */
}

2) use the force-wrap mixin from Compass.

3) I was just looking into this as well and I think might also work (but I need to test browser support more completely):

.break-me {
    word-wrap: break-word;
    overflow-wrap: break-word;
}

Reference: wrapping content

How to give a pandas/matplotlib bar graph custom colors

I found the easiest way is to use the colormap parameter in .plot() with one of the preset color gradients:

df.plot(kind='bar', stacked=True, colormap='Paired')

enter image description here

You can find a large list of preset colormaps here.

colormaps

Adjust icon size of Floating action button (fab)

You can use iconSize like this:

    floatingActionButton: FloatingActionButton(
      onPressed: () {
        // Add your onPressed code here
      },
      child: IconButton(
        icon: isPlaying
            ? Icon(
                Icons.pause_circle_outline,
              )
            : Icon(
                Icons.play_circle_outline,
              ),
              iconSize: 40,
              
        onPressed: () {
          setState(() {
            isPlaying = !isPlaying;
          });
        },
       
      ),
    ),

Select a dummy column with a dummy value in SQL?

Try this:

select col1, col2, 'ABC' as col3 from Table1 where col1 = 0;

I want to convert std::string into a const wchar_t *

You can use the ATL text conversion macros to convert a narrow (char) string to a wide (wchar_t) one. For example, to convert a std::string:

#include <atlconv.h>
...
std::string str = "Hello, world!";
CA2W pszWide(str.c_str());
loadU(pszWide);

You can also specify a code page, so if your std::string contains UTF-8 chars you can use:

CA2W pszWide(str.c_str(), CP_UTF8);

Very useful but Windows only.

When should I create a destructor?

I have used a destructor (for debug purposes only) to see if an object was being purged from memory in the scope of a WPF application. I was unsure if garbage collection was truly purging the object from memory, and this was a good way to verify.

Counting repeated elements in an integer array

with O(n log(n))

int[] arr1; // your given array
int[] arr2 = new int[arr1.length];
Arrays.sort(arr1);

for (int i = 0; i < arr1.length; i++) {
    arr2[i]++;
    if (i+1 < arr1.length) 
    {
        if (arr1[i] == arr1[i + 1]) {
            arr2[i]++;
            i++;
        }
    }
}

for (int i = 0; i < arr1.length; i++) {
    if(arr2[i]>0)
    System.out.println(arr1[i] + ":" + arr2[i]);
}

Gaussian filter in MATLAB

In MATLAB R2015a or newer, it is no longer necessary (or advisable from a performance standpoint) to use fspecial followed by imfilter since there is a new function called imgaussfilt that performs this operation in one step and more efficiently.

The basic syntax:

B = imgaussfilt(A,sigma) filters image A with a 2-D Gaussian smoothing kernel with standard deviation specified by sigma.

The size of the filter for a given Gaussian standard deviation (sigam) is chosen automatically, but can also be specified manually:

B = imgaussfilt(A,sigma,'FilterSize',[3 3]);

The default is 2*ceil(2*sigma)+1.

Additional features of imgaussfilter are ability to operate on gpuArrays, filtering in frequency or spacial domain, and advanced image padding options. It looks a lot like IPP... hmmm. Plus, there's a 3D version called imgaussfilt3.

Pushing value of Var into an Array

Perhaps $('#fruit').val(); is not returning an array and you need something like:

$("#fruit").val() || []

http://docs.jquery.com/Attributes/val

How to find index of STRING array in Java from a given value?

String carName = // insert code here
int index = -1;
for (int i=0;i<TYPES.length;i++) {
    if (TYPES[i].equals(carName)) {
        index = i;
        break;
    }
}

After this index is the array index of your car, or -1 if it doesn't exist.

C++: Rounding up to the nearest multiple of a number

Endless possibilities, for signed integers only:

n + ((r - n) % r)

MySQL - How to select rows where value is in array?

Use the FIND_IN_SET function:

SELECT t.*
  FROM YOUR_TABLE t
 WHERE FIND_IN_SET(3, t.ids) > 0

How to set up file permissions for Laravel?

Just to state the obvious for anyone viewing this discussion.... if you give any of your folders 777 permissions, you are allowing ANYONE to read, write and execute any file in that directory.... what this means is you have given ANYONE (any hacker or malicious person in the entire world) permission to upload ANY file, virus or any other file, and THEN execute that file...

IF YOU ARE SETTING YOUR FOLDER PERMISSIONS TO 777 YOU HAVE OPENED YOUR SERVER TO ANYONE THAT CAN FIND THAT DIRECTORY. Clear enough??? :)

There are basically two ways to setup your ownership and permissions. Either you give yourself ownership or you make the webserver the owner of all files.

Webserver as owner (the way most people do it, and the Laravel doc's way):

assuming www-data (it could be something else) is your webserver user.

sudo chown -R www-data:www-data /path/to/your/laravel/root/directory

if you do that, the webserver owns all the files, and is also the group, and you will have some problems uploading files or working with files via FTP, because your FTP client will be logged in as you, not your webserver, so add your user to the webserver user group:

sudo usermod -a -G www-data ubuntu

Of course, this assumes your webserver is running as www-data (the Homestead default), and your user is ubuntu (it's vagrant if you are using Homestead).

Then you set all your directories to 755 and your files to 644... SET file permissions

sudo find /path/to/your/laravel/root/directory -type f -exec chmod 644 {} \;    

SET directory permissions

sudo find /path/to/your/laravel/root/directory -type d -exec chmod 755 {} \;

Your user as owner

I prefer to own all the directories and files (it makes working with everything much easier), so, go to your laravel root directory:

cd /var/www/html/laravel >> assuming this is your current root directory
sudo chown -R $USER:www-data .

Then I give both myself and the webserver permissions:

sudo find . -type f -exec chmod 664 {} \;   
sudo find . -type d -exec chmod 775 {} \;

Then give the webserver the rights to read and write to storage and cache

Whichever way you set it up, then you need to give read and write permissions to the webserver for storage, cache and any other directories the webserver needs to upload or write too (depending on your situation), so run the commands from bashy above :

sudo chgrp -R www-data storage bootstrap/cache
sudo chmod -R ug+rwx storage bootstrap/cache

Now, you're secure and your website works, AND you can work with the files fairly easily

this is error ORA-12154: TNS:could not resolve the connect identifier specified?

The database must have a name (example DB1), try this one:

OracleConnection con = new OracleConnection("data source=DB1;user id=fastecit;password=fastecit"); 

In case the TNS is not defined you can also try this one:

OracleConnection con = new OracleConnection("Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=DB1)));
User Id=fastecit;Password=fastecit"); 

How to convert a string of numbers to an array of numbers?

Map it to integers:

a.split(',').map(function(i){
    return parseInt(i, 10);
})

map looks at every array item, passes it to the function provided and returns an array with the return values of that function. map isn't available in old browsers, but most libraries like jQuery or underscore include a cross-browser version.

Or, if you prefer loops:

var res = a.split(",");
for (var i=0; i<res.length; i++)
{
    res[i] = parseInt(res[i], 10);
}

How to include js file in another js file?

It is not possible directly. You may as well write some preprocessor which can handle that.

If I understand it correctly then below are the things that can be helpful to achieve that:

  • Use a pre-processor which will run through your JS files for example looking for patterns like "@import somefile.js" and replace them with the content of the actual file. Nicholas Zakas(Yahoo) wrote one such library in Java which you can use (http://www.nczonline.net/blog/2009/09/22/introducing-combiner-a-javascriptcss-concatenation-tool/)

  • If you are using Ruby on Rails then you can give Jammit asset packaging a try, it uses assets.yml configuration file where you can define your packages which can contain multiple files and then refer them in your actual webpage by the package name.

  • Try using a module loader like RequireJS or a script loader like LabJs with the ability to control the loading sequence as well as taking advantage of parallel downloading.

JavaScript currently does not provide a "native" way of including a JavaScript file into another like CSS ( @import ), but all the above mentioned tools/ways can be helpful to achieve the DRY principle you mentioned. I can understand that it may not feel intuitive if you are from a Server-side background but this is the way things are. For front-end developers this problem is typically a "deployment and packaging issue".

Hope it helps.

Customizing Bootstrap CSS template

The best option in my opinion is to compile a custom LESS file including bootstrap.less, a custom variables.less file and your own rules :

  1. Clone bootstrap in your root folder : git clone https://github.com/twbs/bootstrap.git
  2. Rename it "bootstrap"
  3. Create a package.json file : https://gist.github.com/jide/8440609
  4. Create a Gruntfile.js : https://gist.github.com/jide/8440502
  5. Create a "less" folder
  6. Copy bootstrap/less/variables.less into the "less" folder
  7. Change the font path : @icon-font-path: "../bootstrap/fonts/";
  8. Create a custom style.less file in the "less" folder which imports bootstrap.less and your custom variables.less file : https://gist.github.com/jide/8440619
  9. Run npm install
  10. Run grunt watch

Now you can modify the variables any way you want, override bootstrap rules in your custom style.less file, and if some day you want to update bootstrap, you can replace the whole bootstrap folder !

EDIT: I created a Bootstrap boilerplate using this technique : https://github.com/jide/bootstrap-boilerplate

Using PI in python 2.7

Python 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import math
>>> math.pi
3.141592653589793

Check out the Python tutorial on modules and how to use them.

As for the second part of your question, Python comes with batteries included, of course:

>>> math.radians(90)
1.5707963267948966
>>> math.radians(180)
3.141592653589793

Failed to execute 'postMessage' on 'DOMWindow': The target origin provided does not match the recipient window's origin ('null')

In my case SSL certificate was invalid for iframe domain, so make sure that iframe URL you're trying to send messages to is opening w/o any issues (in case you load your iframe over https).

Adding minutes to date time in PHP

$minutes_to_add = 5;

$time = new DateTime('2011-11-17 05:05');
$time->add(new DateInterval('PT' . $minutes_to_add . 'M'));

$stamp = $time->format('Y-m-d H:i');

The ISO 8601 standard for duration is a string in the form of P{y}Y{m1}M{d}DT{h}H{m2}M{s}S where the {*} parts are replaced by a number value indicating how long the duration is.

For example, P1Y2DT5S means 1 year, 2 days, and 5 seconds.

In the example above, we are providing PT5M (or 5 minutes) to the DateInterval constructor.

Angular CLI - Please add a @NgModule annotation when using latest

In my case, I created a new ChildComponent in Parentcomponent whereas both in the same module but Parent is registered in a shared module so I created ChildComponent using CLI which registered Child in the current module but my parent was registered in the shared module.

So register the ChildComponent in Shared Module manually.

SQL How to Select the most recent date item

Assuming your RDBMS know window functions and CTE and USER_ID is the patient's id:

WITH TT AS (
    SELECT *, ROW_NUMBER() OVER(PARTITION BY USER_ID ORDER BY DOCUMENT_DATE DESC) AS N
    FROM test_table
)
SELECT *
FROM TT
WHERE N = 1;

I assumed you wanted to sort by DOCUMENT_DATE, you can easily change that if wanted. If your RDBMS doesn't know window functions, you'll have to do a join :

SELECT *
FROM test_table T1
INNER JOIN (SELECT USER_ID, MAX(DOCUMENT_DATE) AS maxDate
            FROM test_table
            GROUP BY USER_ID) T2
    ON T1.USER_ID = T2.USER_ID
        AND T1.DOCUMENT_DATE = T2.maxDate;

It would be good to tell us what your RDBMS is though. And this query selects the most recent date for every patient, you can add a condition for a given patient.

C# How to determine if a number is a multiple of another?

I don't get that part about the string stuff, but why don't you use the modulo operator (%) to check if a number is dividable by another? If a number is dividable by another, the other is automatically a multiple of that number.

It goes like that:

   int a = 10; int b = 5;

   // is a a multiple of b 
   if ( a % b == 0 )  ....

Debug message "Resource interpreted as other but transferred with MIME type application/javascript"

On APACHE

Append these MIME types to .htaccess in your root. I recommend the second line, as it may help prevent any future potential MIME interpretation warnings with CSS files.

AddType application/x-javascript .js
AddType text/css .css    

Restart Your Apache...

On NGINX

Add to your nginx.conf or your mime.types import file (Recommended Method). Add any or all as needed/relevant.

types {
    text/html                             html htm shtml;
    text/css                              css;
    text/xml                              xml;
    image/gif                             gif;
    image/jpeg                            jpeg jpg;
    application/x-javascript              js;
    application/rss+xml                   rss;
    text/plain                            txt;
    image/png                             png;
    image/tiff                            tif tiff;
    image/svg+xml                         svg svgz;
    image/webp                            webp;
    application/postscript                ps eps ai;
    application/pdf                       pdf;
    application/rtf                       rtf;
    application/vnd.ms-excel              xls;
    application/vnd.ms-powerpoint         ppt;
    application/msword                    doc;
    application/x-shockwave-flash         swf;
    application/xhtml+xml                 xhtml;
    application/zip                       zip;
}

CSS: stretching background image to 100% width and height of screen?

html, body {
    min-height: 100%;
}

Will do the trick.

By default, even html and body are only as big as the content they hold, but never more than the width/height of the windows. This can often lead to quite strange results.

You might also want to read http://css-tricks.com/perfect-full-page-background-image/

There are some great ways do achieve a very good and scalable full background image.

Fix footer to bottom of page

We can use FlexBox for Sticky Footer and Header without using POSITIONS in CSS.

_x000D_
_x000D_
.container {_x000D_
  display: flex;_x000D_
  flex-direction: column;_x000D_
  height: 100vh;_x000D_
}_x000D_
_x000D_
header {_x000D_
  height: 50px;_x000D_
  flex-shrink: 0;_x000D_
  background-color: #037cf5;_x000D_
}_x000D_
_x000D_
footer {_x000D_
  height: 50px;_x000D_
  flex-shrink: 0;_x000D_
  background-color: #134c7d;_x000D_
}_x000D_
_x000D_
main {_x000D_
  flex: 1 0 auto;_x000D_
}
_x000D_
<div class="container">_x000D_
  <header>HEADER</header>_x000D_
  <main class="content">_x000D_
_x000D_
  </main>_x000D_
  <footer>FOOTER</footer>_x000D_
</div>
_x000D_
_x000D_
_x000D_

DEMO - JSFiddle

Note : Check browser supports for FlexBox. caniuse

Retrieve last 100 lines logs

len=`cat filename | wc -l`
len=$(( $len + 1 ))
l=$(( $len - 99 ))
sed -n "${l},${len}p" filename

first line takes the length (Total lines) of file then +1 in the total lines after that we have to fatch 100 records so, -99 from total length then just put the variables in the sed command to fetch the last 100 lines from file

I hope this will help you.

Changing .gitconfig location on Windows

Solution without having to change Windows HOME variable
OS: Windows 10
git version: 2.27.0.windows.1

I use portable version of Git, so all my config files are on my pen-drive(E:). This is what worked for me:

  1. Download portable Git from https://git-scm.com/. Run the file and install it in the required location. I installed it in E:\git.
  2. Run git-bash.exe from E:\git.
  3. I wanted to put .gitconfig and other bash files in E, so I created a folder called home where I want them all in.
    mkdir home
  4. Go to etc folder and open the file called profile (In my case, it's E:\git\etc\profile)
  5. Add absolute path to the home directory we created (or to the directory where you want to have your .gitconfig file located) at the end of the profile file.
    HOME="E:\git\home"

Now it no longer searches in the C:\Users<username> directory for .gitconfig but only looks in your set path above.

$ git config --global --list
fatal: unable to read config file 'E:/git/home/.gitconfig': No such file or directory

It gave an error because there isn't a .gitconfig file there yet. This is just to demonstrate that we have successfully changed the location of the .gitconfig file without changing the HOME directory in Windows.

How to run Java program in terminal with external library JAR

For compiling the java file having dependency on a jar

javac -cp path_of_the_jar/jarName.jar className.java

For executing the class file

java -cp .;path_of_the_jar/jarName.jar className

Conditional formatting based on another cell's value

change the background color of cell B5 based on the value of another cell - C5. If C5 is greater than 80% then the background color is green but if it's below, it will be amber/red.

There is no mention that B5 contains any value so assuming 80% is .8 formatted as percentage without decimals and blank counts as "below":

Select B5, colour "amber/red" with standard fill then Format - Conditional formatting..., Custom formula is and:

=C5>0.8

with green fill and Done.

CF rule example

Force browser to download image files on click

What about using the .click() function and the tag?

(Compressed version)

_x000D_
_x000D_
<a id="downloadtag" href="examplefolder/testfile.txt" hidden download></a>_x000D_
_x000D_
<button onclick="document.getElementById('downloadtag').click()">Download</button>
_x000D_
_x000D_
_x000D_

Now you can trigger it with js. It also doesn't open, as other examples, image and text files!

(js-function version)

_x000D_
_x000D_
function download(){_x000D_
document.getElementById('downloadtag').click();_x000D_
}
_x000D_
<!-- HTML -->_x000D_
<button onclick="download()">Download</button>_x000D_
<a id="downloadtag" href="coolimages/awsome.png" hidden download></a>
_x000D_
_x000D_
_x000D_

Convert file: Uri to File in Android

None of this works for me. I found this to be the working solution. But my case is specific to images.

String[] filePathColumn = { MediaStore.Images.Media.DATA };
Cursor cursor = getActivity().getContentResolver().query(uri, filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String filePath = cursor.getString(columnIndex);
cursor.close();

How do you extract a JAR in a UNIX filesystem with a single command and specify its target directory using the JAR command?

If your jar file already has an absolute pathname as shown, it is particularly easy:

cd /where/you/want/it; jar xf /path/to/jarfile.jar

That is, you have the shell executed by Python change directory for you and then run the extraction.

If your jar file does not already have an absolute pathname, then you have to convert the relative name to absolute (by prefixing it with the path of the current directory) so that jar can find it after the change of directory.

The only issues left to worry about are things like blanks in the path names.

how to read a text file using scanner in Java?

This should help you..:

import java.io.*;
import static java.lang.System.*;
/**
* Write a description of class InRead here.
* 
* @author (your name) 
* @version (a version number or a date)
*/
public class InRead
{
public InRead(String Recipe)
{
    find(Recipe);
}
public void find(String Name){
    String newRecipe= Name+".txt";
    try{
        FileReader fr= new FileReader(newRecipe);
        BufferedReader br= new BufferedReader(fr);

        String str;


    while ((str=br.readLine()) != null){
            out.println(str + "\n");
        }
        br.close();

    }catch (IOException e){
        out.println("File Not Found!");
    }
}

}

Listing available com ports with Python

refinement on moylop260's answer:

import serial.tools.list_ports
comlist = serial.tools.list_ports.comports()
connected = []
for element in comlist:
    connected.append(element.device)
print("Connected COM ports: " + str(connected))

This lists the ports that exist in hardware, including ones that are in use. A whole lot more information exists in the list, per the pyserial tools documentation

Android emulator not able to access the internet

What I have observed is that when you switch wifi connections when the android emulator is running. It isn't able to connect to new wifi.

A simple solution is to restart the android emulator.

How to append in a json file in Python?

Assuming you have a test.json file with the following content:

{"67790": {"1": {"kwh": 319.4}}}

Then, the code below will load the json file, update the data inside using dict.update() and dump into the test.json file:

import json

a_dict = {'new_key': 'new_value'}

with open('test.json') as f:
    data = json.load(f)

data.update(a_dict)

with open('test.json', 'w') as f:
    json.dump(data, f)

Then, in test.json, you'll have:

{"new_key": "new_value", "67790": {"1": {"kwh": 319.4}}}

Hope this is what you wanted.

How to set a Postgresql default value datestamp like 'YYYYMM'?

Right. Better to use a function:

CREATE OR REPLACE FUNCTION yyyymm() RETURNS text
    LANGUAGE 'plpgsql' AS $$
DECLARE
    retval text;
    m integer;
BEGIN
    retval := EXTRACT(year from current_timestamp);
    m := EXTRACT(month from current_timestamp);
    IF m < 10 THEN retval := retval || '0'; END IF;
    RETURN retval || m;
END $$;

SELECT yyyymm();

DROP TABLE foo;
CREATE TABLE foo (
    key             int PRIMARY KEY,
    colname text DEFAULT yyyymm()
    );
INSERT INTO foo (key) VALUES (0);
SELECT * FROM FOO;

This gives me

 key | colname 
-----+---------
   0 | 200905

Make sure you run createlang plpgsql from the Unix command line, if necessary.

Running Python code in Vim

I have this on my .vimrc:

"map <F9> :w<CR>:!python %<CR>"

which saves the current buffer and execute the code with presing only Esc + F9

How to use Select2 with JSON via Ajax request?

In Version 4.0.2 slightly different Just in processResults and in result :

    processResults: function (data) {
        return {
            results: $.map(data.items, function (item) {
                return {
                    text: item.tag_value,
                    id: item.tag_id
                }
            })
        };
    }

You must add data.items in result. items is Json name :

{
  "items": [
    {"id": 1,"name": "Tetris","full_name": "s9xie/hed"},
    {"id": 2,"name": "Tetrisf","full_name": "s9xie/hed"}
  ]
}

Why does Eclipse Java Package Explorer show question mark on some classes?

It means the class is not yet added to the repository.

If your project was checked-out (most probably a CVS project) and you added a new class file, it will have the ? icon.

For other CVS Label Decorations, check http://help.eclipse.org/help33/index.jsp?topic=/org.eclipse.platform.doc.user/reference/ref-cvs-decorations.htm

How do I skip an iteration of a `foreach` loop?

You want:

foreach (int number in numbers) //   <--- go back to here --------+
{                               //                                |
    if (number < 0)             //                                |
    {                           //                                |
        continue;   // Skip the remainder of this iteration. -----+
    }

    // do work
}

Here's more about the continue keyword.


Update: In response to Brian's follow-up question in the comments:

Could you further clarify what I would do if I had nested for loops, and wanted to skip the iteration of one of the extended ones?

for (int[] numbers in numberarrays) {
  for (int number in numbers) { // What to do if I want to
                                // jump the (numbers/numberarrays)?
  }
}

A continue always applies to the nearest enclosing scope, so you couldn't use it to break out of the outermost loop. If a condition like that arises, you'd need to do something more complicated depending on exactly what you want, like break from the inner loop, then continue on the outer loop. See here for the documentation on the break keyword. The break C# keyword is similar to the Perl last keyword.

Also, consider taking Dustin's suggestion to just filter out values you don't want to process beforehand:

foreach (var basket in baskets.Where(b => b.IsOpen())) {
  foreach (var fruit in basket.Where(f => f.IsTasty())) {
    cuteAnimal.Eat(fruit); // Om nom nom. You don't need to break/continue
                           // since all the fruits that reach this point are
                           // in available baskets and tasty.
  }
}

Jquery click not working with ipad

Thanks to the previous commenters I found all the following worked for me:

Either adding an onclick stub to the element

onclick="void(0);" 

or user a cursor pointer style

style="cursor:pointer;"

or as in my existing code my jquery code needed tap added

$(document).on('click tap','.ciAddLike',function(event)
{
    alert('like added!'); // stopped working in ios safari until tap added
});

I am adding a cross-reference back to the Apple Docs for those interested. See Apple Docs:Making Events Clickable

(I'm not sure exactly when my hybrid app stopped processing clicks but I seem to remember they worked iOS 7 and earlier.)

How to calculate the bounding box for a given lat/lng location?

Here is Federico Ramponi's answer in Go. Note: no error-checking :(

import (
    "math"
)

// Semi-axes of WGS-84 geoidal reference
const (
    // Major semiaxis (meters)
    WGS84A = 6378137.0
    // Minor semiaxis (meters)
    WGS84B = 6356752.3
)

// BoundingBox represents the geo-polygon that encompasses the given point and radius
type BoundingBox struct {
    LatMin float64
    LatMax float64
    LonMin float64
    LonMax float64
}

// Convert a degree value to radians
func deg2Rad(deg float64) float64 {
    return math.Pi * deg / 180.0
}

// Convert a radian value to degrees
func rad2Deg(rad float64) float64 {
    return 180.0 * rad / math.Pi
}

// Get the Earth's radius in meters at a given latitude based on the WGS84 ellipsoid
func getWgs84EarthRadius(lat float64) float64 {
    an := WGS84A * WGS84A * math.Cos(lat)
    bn := WGS84B * WGS84B * math.Sin(lat)

    ad := WGS84A * math.Cos(lat)
    bd := WGS84B * math.Sin(lat)

    return math.Sqrt((an*an + bn*bn) / (ad*ad + bd*bd))
}

// GetBoundingBox returns a BoundingBox encompassing the given lat/long point and radius
func GetBoundingBox(latDeg float64, longDeg float64, radiusKm float64) BoundingBox {
    lat := deg2Rad(latDeg)
    lon := deg2Rad(longDeg)
    halfSide := 1000 * radiusKm

    // Radius of Earth at given latitude
    radius := getWgs84EarthRadius(lat)

    pradius := radius * math.Cos(lat)

    latMin := lat - halfSide/radius
    latMax := lat + halfSide/radius
    lonMin := lon - halfSide/pradius
    lonMax := lon + halfSide/pradius

    return BoundingBox{
        LatMin: rad2Deg(latMin),
        LatMax: rad2Deg(latMax),
        LonMin: rad2Deg(lonMin),
        LonMax: rad2Deg(lonMax),
    }
}

How to print the ld(linker) search path

I'm not sure that there is any option for simply printing the full effective search path.

But: the search path consists of directories specified by -L options on the command line, followed by directories added to the search path by SEARCH_DIR("...") directives in the linker script(s). So you can work it out if you can see both of those, which you can do as follows:

If you're invoking ld directly:

  • The -L options are whatever you've said they are.
  • To see the linker script, add the --verbose option. Look for the SEARCH_DIR("...") directives, usually near the top of the output. (Note that these are not necessarily the same for every invocation of ld -- the linker has a number of different built-in default linker scripts, and chooses between them based on various other linker options.)

If you're linking via gcc:

  • You can pass the -v option to gcc so that it shows you how it invokes the linker. In fact, it normally does not invoke ld directly, but indirectly via a tool called collect2 (which lives in one of its internal directories), which in turn invokes ld. That will show you what -L options are being used.
  • You can add -Wl,--verbose to the gcc options to make it pass --verbose through to the linker, to see the linker script as described above.

Sending a JSON HTTP POST request from Android

try some thing like blow:

SString otherParametersUrServiceNeed =  "Company=acompany&Lng=test&MainPeriod=test&UserID=123&CourseDate=8:10:10";
String request = "http://android.schoolportal.gr/Service.svc/SaveValues";

URL url = new URL(request); 
HttpURLConnection connection = (HttpURLConnection) url.openConnection();   
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setInstanceFollowRedirects(false); 
connection.setRequestMethod("POST"); 
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); 
connection.setRequestProperty("charset", "utf-8");
connection.setRequestProperty("Content-Length", "" + Integer.toString(otherParametersUrServiceNeed.getBytes().length));
connection.setUseCaches (false);

DataOutputStream wr = new DataOutputStream(connection.getOutputStream ());
wr.writeBytes(otherParametersUrServiceNeed);

   JSONObject jsonParam = new JSONObject();
jsonParam.put("ID", "25");
jsonParam.put("description", "Real");
jsonParam.put("enable", "true");

wr.writeBytes(jsonParam.toString());

wr.flush();
wr.close();

References :

  1. http://www.xyzws.com/Javafaq/how-to-use-httpurlconnection-post-data-to-web-server/139
  2. Java - sending HTTP parameters via POST method easily

Installation Issue with matplotlib Python

Problem Cause

In mac os image rendering back end of matplotlib (what-is-a-backend to render using the API of Cocoa by default). There are Qt4Agg and GTKAgg and as a back-end is not the default. Set the back end of macosx that is differ compare with other windows or linux os.

Solution

  • I assume you have installed the pip matplotlib, there is a directory in your root called ~/.matplotlib.
  • Create a file ~/.matplotlib/matplotlibrc there and add the following code: backend: TkAgg

From this link you can try different diagrams.

Ansible: filter a list by its attributes

Not necessarily better, but since it's nice to have options here's how to do it using Jinja statements:

- debug:
    msg: "{% for address in network.addresses.private_man %}\
        {% if address.type == 'fixed' %}\
          {{ address.addr }}\
        {% endif %}\
      {% endfor %}"

Or if you prefer to put it all on one line:

- debug:
    msg: "{% for address in network.addresses.private_man if address.type == 'fixed' %}{{ address.addr }}{% endfor %}"

Which returns:

ok: [localhost] => {
    "msg": "172.16.1.100"
}

DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled

  • When you create a stored function, you must declare either that it is deterministic or that it does not modify data. Otherwise, it may be unsafe for data recovery or replication.

  • By default, for a CREATE FUNCTION statement to be accepted, at least one of DETERMINISTIC, NO SQL, or READS SQL DATA must be specified explicitly. Otherwise an error occurs:

To fix this issue add following lines After Return and Before Begin statement:

READS SQL DATA
DETERMINISTIC

For Example :

CREATE FUNCTION f2()
RETURNS CHAR(36) CHARACTER SET utf8
/*ADD HERE */
READS SQL DATA
DETERMINISTIC
BEGIN

For more detail about this issue please read Here

How do I perform a JAVA callback between classes?

Define an interface, and implement it in the class that will receive the callback.

Have attention to the multi-threading in your case.

Code example from http://cleancodedevelopment-qualityseal.blogspot.com.br/2012/10/understanding-callbacks-with-java.html

interface CallBack {                   //declare an interface with the callback methods, so you can use on more than one class and just refer to the interface
    void methodToCallBack();
}

class CallBackImpl implements CallBack {          //class that implements the method to callback defined in the interface
    public void methodToCallBack() {
        System.out.println("I've been called back");
    }
}

class Caller {

    public void register(CallBack callback) {
        callback.methodToCallBack();
    }

    public static void main(String[] args) {
        Caller caller = new Caller();
        CallBack callBack = new CallBackImpl();       //because of the interface, the type is Callback even thought the new instance is the CallBackImpl class. This alows to pass different types of classes that have the implementation of CallBack interface
        caller.register(callBack);
    }
} 

In your case, apart from multi-threading you could do like this:

interface ServerInterface {
    void newSeverConnection(Socket socket);
}

public class Server implements ServerInterface {

    public Server(int _address) {
        System.out.println("Starting Server...");
        serverConnectionHandler = new ServerConnections(_address, this);
        workers.execute(serverConnectionHandler);
        System.out.println("Do something else...");
    }

    void newServerConnection(Socket socket) {
        System.out.println("A function of my child class was called.");
    }

}

public class ServerConnections implements Runnable {

    private ServerInterface serverInterface;

    public ServerConnections(int _serverPort, ServerInterface _serverInterface) {
      serverPort = _serverPort;
      serverInterface = _serverInterface;
    }

    @Override
    public void run() {
        System.out.println("Starting Server Thread...");

        if (serverInterface == null) {
            System.out.println("Server Thread error: callback null");
        }

        try {
            mainSocket = new ServerSocket(serverPort);

            while (true) {
                serverInterface.newServerConnection(mainSocket.accept());
            }
        } catch (IOException ex) {
            Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

Multi-threading

Remember this does not handle multi-threading, this is another topic and can have various solutions depending on the project.

The observer-pattern

The observer-pattern does nearly this, the major difference is the use of an ArrayList for adding more than one listener. Where this is not needed, you get better performance with one reference.

Reference excel worksheet by name?

To expand on Ryan's answer, when you are declaring variables (using Dim) you can cheat a little bit by using the predictive text feature in the VBE, as in the image below. screenshot of predictive text in VBE

If it shows up in that list, then you can assign an object of that type to a variable. So not just a Worksheet, as Ryan pointed out, but also a Chart, Range, Workbook, Series and on and on.

You set that variable equal to the object you want to manipulate and then you can call methods, pass it to functions, etc, just like Ryan pointed out for this example. You might run into a couple snags when it comes to collections vs objects (Chart or Charts, Range or Ranges, etc) but with trial and error you'll get it for sure.

Bootstrap full responsive navbar with logo or brand name text

The placeholder image you're including has a height of 50px. It is wrapped in an anchor (.navbar-brand) with a padding-top of 15px and a height of 50px. That's why the placeholder logo flows out of the bar. Try including a smaller image or play with the anchor's padding by assigning a class or an id to it wich you can reference in your css.

EDIT Or remove the static height: 50px from .navbar-brand. Your navbar will then take the height of its highest child.

h3 in bootstrap by default has a padding-top of 20px. Again, it is wrapped with that padding-top: 15px anchor. That's why it's not vertically centered like you want it. You could give the h3 a class or and id that resets the margin-top. And the same you could do with the padding of the anchor.

Here's something to play with: http://jsbin.com/jelec/1/edit?html,output

How to print table using Javascript?

One cheeky solution :

  function printDiv(divID) {
        //Get the HTML of div
        var divElements = document.getElementById(divID).innerHTML;
        //Get the HTML of whole page
        var oldPage = document.body.innerHTML;
        //Reset the page's HTML with div's HTML only
        document.body.innerHTML = 
          "<html><head><title></title></head><body>" + 
          divElements + "</body>";
        //Print Page
        window.print();
        //Restore orignal HTML
        document.body.innerHTML = oldPage;

    }

HTML :

<form id="form1" runat="server">
    <div id="printablediv" style="width: 100%; background-color: Blue; height: 200px">
        Print me I am in 1st Div
    </div>
    <div id="donotprintdiv" style="width: 100%; background-color: Gray; height: 200px">
        I am not going to print
    </div>
    <input type="button" value="Print 1st Div" onclick="javascript:printDiv('printablediv')" />
</form>

ASP.NET Identity DbContext confusion

If you drill down through the abstractions of the IdentityDbContext you'll find that it looks just like your derived DbContext. The easiest route is Olav's answer, but if you want more control over what's getting created and a little less dependency on the Identity packages have a look at my question and answer here. There's a code example if you follow the link, but in summary you just add the required DbSets to your own DbContext subclass.

Iterate through dictionary values?

You can just look for the value that corresponds with the key and then check if the input is equal to the key.

for key in PIX0:
    NUM = input("Which standard has a resolution of %s " % PIX0[key])
    if NUM == key:

Also, you will have to change the last line to fit in, so it will print the key instead of the value if you get the wrong answer.

print("I'm sorry but thats wrong. The correct answer was: %s." % key )

Also, I would recommend using str.format for string formatting instead of the % syntax.

Your full code should look like this (after adding in string formatting)

PIX0 = {"QVGA":"320x240", "VGA":"640x480", "SVGA":"800x600"}

for key in PIX0:
    NUM = input("Which standard has a resolution of {}".format(PIX0[key]))
    if NUM == key:
        print ("Nice Job!")
        count = count + 1
    else:
        print("I'm sorry but that's wrong. The correct answer was: {}.".format(key))

Getting first value from map in C++

begin() returns the first pair, (precisely, an iterator to the first pair, and you can access the key/value as ->first and ->second of that iterator)

Reading from stdin

You can do something like this to read 10 bytes:

char buffer[10];
read(STDIN_FILENO, buffer, 10);

remember read() doesn't add '\0' to terminate to make it string (just gives raw buffer).

To read 1 byte at a time:

char ch;
while(read(STDIN_FILENO, &ch, 1) > 0)
{
 //do stuff
}

and don't forget to #include <unistd.h>, STDIN_FILENO defined as macro in this file.

There are three standard POSIX file descriptors, corresponding to the three standard streams, which presumably every process should expect to have:

Integer value   Name
       0        Standard input (stdin)
       1        Standard output (stdout)
       2        Standard error (stderr)

So instead STDIN_FILENO you can use 0.

Edit:
In Linux System you can find this using following command:

$ sudo grep 'STDIN_FILENO' /usr/include/* -R | grep 'define'
/usr/include/unistd.h:#define   STDIN_FILENO    0   /* Standard input.  */

Notice the comment /* Standard input. */

MySQL - Cannot add or update a child row: a foreign key constraint fails

Even though this is pretty old, just chiming in to say that what is useful in @Sidupac's answer is the FOREIGN_KEY_CHECKS=0.

This answer is not an option when you are using something that manages the database schema for you (JPA in my case) but the problem may be that there are "orphaned" entries in your table (referencing a foreign key that might not exist).

This can often happen when you convert a MySQL table from MyISAM to InnoDB since referential integrity isn't really a thing with the former.

How to set a timer in android

Here we go.. We will need two classes. I am posting a code which changes mobile audio profile after each 5 seconds (5000 mili seconds) ...

Our 1st Class

public class ChangeProfileActivityMain extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        Timer timer = new Timer();
        TimerTask updateProfile = new CustomTimerTask(ChangeProfileActivityMain.this);
        timer.scheduleAtFixedRate(updateProfile, 0, 5000);
    }

}

Our 2nd Class

public class CustomTimerTask extends TimerTask {

    private AudioManager audioManager;
    private Context context;
    private Handler mHandler = new Handler();

    // Write Custom Constructor to pass Context
    public CustomTimerTask(Context con) {
        this.context = con;
    }

    @Override
    public void run() {
        // TODO Auto-generated method stub

        // your code starts here.
        // I have used Thread and Handler as we can not show Toast without starting new thread when we are inside a thread.
        // As TimePicker has run() thread running., So We must show Toast through Handler.post in a new Thread. Thats how it works in Android..
        new Thread(new Runnable() {
            @Override
            public void run() {
                audioManager = (AudioManager) context.getApplicationContext().getSystemService(Context.AUDIO_SERVICE);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        if(audioManager.getRingerMode() == AudioManager.RINGER_MODE_SILENT) {
                            audioManager.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
                            Toast.makeText(context, "Ringer Mode set to Normal", Toast.LENGTH_SHORT).show();
                        } else {
                            audioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
                            Toast.makeText(context, "Ringer Mode set to Silent", Toast.LENGTH_SHORT).show();
                        }
                    }
                });
            }
        }).start();

    }

}

How to install a gem or update RubyGems if it fails with a permissions error

I found this how-to for sudoless gem:

  1. brew install rbenv ruby-build
  2. sudo gem update --system
  3. add exports to .bashrc:

    export RBENV_ROOT="$(brew --prefix rbenv)"
    export GEM_HOME="$(brew --prefix)/opt/gems"
    export GEM_PATH="$(brew --prefix)/opt/gems"
    
  4. And finally add this to your ~/.gemrc:

    gem: -n/usr/local/bin
    
  5. gem update --system

How do I send a POST request as a JSON?

for python 3.4.2 I found the following will work:

import urllib.request
import json      

body = {'ids': [12, 14, 50]}  
myurl = "http://www.testmycode.com"

req = urllib.request.Request(myurl)
req.add_header('Content-Type', 'application/json; charset=utf-8')
jsondata = json.dumps(body)
jsondataasbytes = jsondata.encode('utf-8')   # needs to be bytes
req.add_header('Content-Length', len(jsondataasbytes))
response = urllib.request.urlopen(req, jsondataasbytes)

How can I make IntelliJ IDEA update my dependencies from Maven?

Uncheck

"Work Offline"

in Settings -> Maven ! It worked for me ! :D

Where to put the gradle.properties file

Actually there are 3 places where gradle.properties can be placed:

  1. Under gradle user home directory defined by the GRADLE_USER_HOME environment variable, which if not set defaults to USER_HOME/.gradle
  2. The sub-project directory (myProject2 in your case)
  3. The root project directory (under myProject)

Gradle looks for gradle.properties in all these places while giving precedence to properties definition based on the order above. So for example, for a property defined in gradle user home directory (#1) and the sub-project (#2) its value will be taken from gradle user home directory (#1).

You can find more details about it in gradle documentation here.

phpMyAdmin - config.inc.php configuration?

I had the same problem for days until I noticed (how could I look at it and not read the code :-(..) that config.inc.php is calling config-db.php

** MySql Server version: 5.7.5-m15
** Apache/2.4.10 (Ubuntu)
** phpMyAdmin 4.2.9.1deb0.1

/etc/phpmyadmin/config-db.php:

$dbuser='yourDBUserName';
$dbpass='';
$basepath='';
$dbname='phpMyAdminDBName';
$dbserver='';
$dbport='';
$dbtype='mysql';

Here you need to define your username, password, dbname and others that are showing empty' use default unless you changed their configuration. That solved the issue for me.
U hope it helps you.
latest.phpmyadmin.docs

Difference between sh and bash

The Differences in as easy as much possible: After having a basic understanding, the other comments posted above will be easier to catch.

Shell - "Shell" is a program, which facilitates the interaction between the user and the operating system (kernel). There are many shell implementation available, like sh, bash, csh, zsh...etc.

Using any of the Shell programs, we will be able to execute commands that are supported by that shell program.

Bash - It derived from Bourne-again Shell. Using this program, we will be able to execute all the commands specified by Shell. Also, we will be able to execute some commands that are specifically added to this program. Bash has backward compatibility with sh.

Sh - It derived from Bourne Shell. "sh" supports all the commands specified in the shell. Means, Using this program, we will be able to execute all the commands specified by Shell.

For more information, do: - https://man.cx/sh - https://man.cx/bash

c++ "Incomplete type not allowed" error accessing class reference information (Circular dependency with forward declaration)

Player.cpp require the definition of Ball class. So simply add #include "Ball.h"

Player.cpp:

#include "Player.h"
#include "Ball.h"

void Player::doSomething(Ball& ball) {
    ball.ballPosX += 10;                   // incomplete type error occurs here.
}

what's data-reactid attribute in html?

It's a custom html attribute but probably in this case is used by the Facebook React JS Library.

Take a look: http://facebook.github.io/react/

Using the RUN instruction in a Dockerfile with 'source' does not work

Original Answer

FROM ubuntu:14.04
RUN rm /bin/sh && ln -s /bin/bash /bin/sh

This should work for every Ubuntu docker base image. I generally add this line for every Dockerfile I write.

Edit by a concerned bystander

If you want to get the effect of "use bash instead of sh throughout this entire Dockerfile", without altering and possibly damaging* the OS inside the container, you can just tell Docker your intention. That is done like so:

SHELL ["/bin/bash", "-c"]

* The possible damage is that many scripts in Linux (on a fresh Ubuntu install grep -rHInE '/bin/sh' / returns over 2700 results) expect a fully POSIX shell at /bin/sh. The bash shell isn't just POSIX plus extra builtins. There are builtins (and more) that behave entirely different than those in POSIX. I FULLY support avoiding POSIX (and the fallacy that any script that you didn't test on another shell is going to work because you think you avoided basmisms) and just using bashism. But you do that with a proper shebang in your script. Not by pulling the POSIX shell out from under the entire OS. (Unless you have time to verify all 2700 plus scripts that come with Linux plus all those in any packages you install.)

More detail in this answer below. https://stackoverflow.com/a/45087082/117471

how to define variable in jquery

Remember jQuery is a JavaScript library, i.e. like an extension. That means you can use both jQuery and JavaScript in the same function (restrictions apply).

You declare/create variables in the same way as in Javascript: var example;

However, you can use jQuery for assigning values to variables:

var example = $("#unique_product_code").html();

Instead of pure JavaScript:

var example = document.getElementById("unique_product_code").innerHTML;

Is jQuery $.browser Deprecated?

Updated! 3/24/2015 (scroll below hr)

lonesomeday's answer is absolutely correct, I just thought I would add this tidbit. I had made a method a while back for getting browser in Vanilla JS and eventually curved it to replace jQuery.browser in later versions of jQuery. It does not interfere with any part of the new jQuery lib, but provides the same functionality of the traditional jQuery.browser object, as well as some other little features.


New Extended Version!

Is much more thorough for newer browser. Also, 90+% accuracy on mobile testing! I won't say 100%, as I haven't tested on every mobile browser, but new feature adds $.browser.mobile boolean/string. It's false if not mobile, else it will be a String name for the mobile device or browser (Best Guesss like: Android, RIM Tablet, iPod, etc...).

One possible caveat, may not work with some older (unsupported) browsers as it is completely reliant on userAgent string.

JS Minified

/* quick & easy cut & paste */
;;(function($){if(!$.browser&&1.9<=parseFloat($.fn.jquery)){var a={browser:void 0,version:void 0,mobile:!1};navigator&&navigator.userAgent&&(a.ua=navigator.userAgent,a.webkit=/WebKit/i.test(a.ua),a.browserArray="MSIE Chrome Opera Kindle Silk BlackBerry PlayBook Android Safari Mozilla Nokia".split(" "),/Sony[^ ]*/i.test(a.ua)?a.mobile="Sony":/RIM Tablet/i.test(a.ua)?a.mobile="RIM Tablet":/BlackBerry/i.test(a.ua)?a.mobile="BlackBerry":/iPhone/i.test(a.ua)?a.mobile="iPhone":/iPad/i.test(a.ua)?a.mobile="iPad":/iPod/i.test(a.ua)?a.mobile="iPod":/Opera Mini/i.test(a.ua)?a.mobile="Opera Mini":/IEMobile/i.test(a.ua)?a.mobile="IEMobile":/BB[0-9]{1,}; Touch/i.test(a.ua)?a.mobile="BlackBerry":/Nokia/i.test(a.ua)?a.mobile="Nokia":/Android/i.test(a.ua)&&(a.mobile="Android"),/MSIE|Trident/i.test(a.ua)?(a.browser="MSIE",a.version=/MSIE/i.test(navigator.userAgent)&&0<parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,""))?parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,"")):"Edge",/Trident/i.test(a.ua)&&/rv:([0-9]{1,}[\.0-9]{0,})/.test(a.ua)&&(a.version=parseFloat(a.ua.match(/rv:([0-9]{1,}[\.0-9]{0,})/)[1].replace(/[^0-9\.]/g,"")))):/Chrome/.test(a.ua)?(a.browser="Chrome",a.version=parseFloat(a.ua.split("Chrome/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Opera/.test(a.ua)?(a.browser="Opera",a.version=parseFloat(a.ua.split("Version/")[1].replace(/[^0-9\.]/g,""))):/Kindle|Silk|KFTT|KFOT|KFJWA|KFJWI|KFSOWI|KFTHWA|KFTHWI|KFAPWA|KFAPWI/i.test(a.ua)?(a.mobile="Kindle",/Silk/i.test(a.ua)?(a.browser="Silk",a.version=parseFloat(a.ua.split("Silk/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Kindle/i.test(a.ua)&&/Version/i.test(a.ua)&&(a.browser="Kindle",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,"")))):/BlackBerry/.test(a.ua)?(a.browser="BlackBerry",a.version=parseFloat(a.ua.split("/")[1].replace(/[^0-9\.]/g,""))):/PlayBook/.test(a.ua)?(a.browser="PlayBook",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/BB[0-9]{1,}; Touch/.test(a.ua)?(a.browser="Blackberry",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Android/.test(a.ua)?(a.browser="Android",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Safari/.test(a.ua)?(a.browser="Safari",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Firefox/.test(a.ua)?(a.browser="Mozilla",a.version=parseFloat(a.ua.split("Firefox/")[1].replace(/[^0-9\.]/g,""))):/Nokia/.test(a.ua)&&(a.browser="Nokia",a.version=parseFloat(a.ua.split("Browser")[1].replace(/[^0-9\.]/g,""))));if(a.browser)for(var b in a.browserArray)a[a.browserArray[b].toLowerCase()]=a.browser==a.browserArray[b];$.extend(!0,$.browser={},a)}})(jQuery);
/* quick & easy cut & paste */

jsFiddle "jQuery Plugin: Get Browser (Extended Alt Edition)"

_x000D_
_x000D_
/** jQuery.browser_x000D_
 * @author J.D. McKinstry (2014)_x000D_
 * @description Made to replicate older jQuery.browser command in jQuery versions 1.9+_x000D_
 * @see http://jsfiddle.net/SpYk3/wsqfbe4s/_x000D_
 *_x000D_
 * @extends jQuery_x000D_
 * @namespace jQuery.browser_x000D_
 * @example jQuery.browser.browser == 'browserNameInLowerCase'_x000D_
 * @example jQuery.browser.version_x000D_
 * @example jQuery.browser.mobile @returns BOOLEAN_x000D_
 * @example jQuery.browser['browserNameInLowerCase']_x000D_
 * @example jQuery.browser.chrome @returns BOOLEAN_x000D_
 * @example jQuery.browser.safari @returns BOOLEAN_x000D_
 * @example jQuery.browser.opera @returns BOOLEAN_x000D_
 * @example jQuery.browser.msie @returns BOOLEAN_x000D_
 * @example jQuery.browser.mozilla @returns BOOLEAN_x000D_
 * @example jQuery.browser.webkit @returns BOOLEAN_x000D_
 * @example jQuery.browser.ua @returns navigator.userAgent String_x000D_
 */_x000D_
;;(function($){if(!$.browser&&1.9<=parseFloat($.fn.jquery)){var a={browser:void 0,version:void 0,mobile:!1};navigator&&navigator.userAgent&&(a.ua=navigator.userAgent,a.webkit=/WebKit/i.test(a.ua),a.browserArray="MSIE Chrome Opera Kindle Silk BlackBerry PlayBook Android Safari Mozilla Nokia".split(" "),/Sony[^ ]*/i.test(a.ua)?a.mobile="Sony":/RIM Tablet/i.test(a.ua)?a.mobile="RIM Tablet":/BlackBerry/i.test(a.ua)?a.mobile="BlackBerry":/iPhone/i.test(a.ua)?a.mobile="iPhone":/iPad/i.test(a.ua)?a.mobile="iPad":/iPod/i.test(a.ua)?a.mobile="iPod":/Opera Mini/i.test(a.ua)?a.mobile="Opera Mini":/IEMobile/i.test(a.ua)?a.mobile="IEMobile":/BB[0-9]{1,}; Touch/i.test(a.ua)?a.mobile="BlackBerry":/Nokia/i.test(a.ua)?a.mobile="Nokia":/Android/i.test(a.ua)&&(a.mobile="Android"),/MSIE|Trident/i.test(a.ua)?(a.browser="MSIE",a.version=/MSIE/i.test(navigator.userAgent)&&0<parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,""))?parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,"")):"Edge",/Trident/i.test(a.ua)&&/rv:([0-9]{1,}[\.0-9]{0,})/.test(a.ua)&&(a.version=parseFloat(a.ua.match(/rv:([0-9]{1,}[\.0-9]{0,})/)[1].replace(/[^0-9\.]/g,"")))):/Chrome/.test(a.ua)?(a.browser="Chrome",a.version=parseFloat(a.ua.split("Chrome/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Opera/.test(a.ua)?(a.browser="Opera",a.version=parseFloat(a.ua.split("Version/")[1].replace(/[^0-9\.]/g,""))):/Kindle|Silk|KFTT|KFOT|KFJWA|KFJWI|KFSOWI|KFTHWA|KFTHWI|KFAPWA|KFAPWI/i.test(a.ua)?(a.mobile="Kindle",/Silk/i.test(a.ua)?(a.browser="Silk",a.version=parseFloat(a.ua.split("Silk/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Kindle/i.test(a.ua)&&/Version/i.test(a.ua)&&(a.browser="Kindle",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,"")))):/BlackBerry/.test(a.ua)?(a.browser="BlackBerry",a.version=parseFloat(a.ua.split("/")[1].replace(/[^0-9\.]/g,""))):/PlayBook/.test(a.ua)?(a.browser="PlayBook",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/BB[0-9]{1,}; Touch/.test(a.ua)?(a.browser="Blackberry",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Android/.test(a.ua)?(a.browser="Android",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Safari/.test(a.ua)?(a.browser="Safari",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Firefox/.test(a.ua)?(a.browser="Mozilla",a.version=parseFloat(a.ua.split("Firefox/")[1].replace(/[^0-9\.]/g,""))):/Nokia/.test(a.ua)&&(a.browser="Nokia",a.version=parseFloat(a.ua.split("Browser")[1].replace(/[^0-9\.]/g,""))));if(a.browser)for(var b in a.browserArray)a[a.browserArray[b].toLowerCase()]=a.browser==a.browserArray[b];$.extend(!0,$.browser={},a)}})(jQuery);_x000D_
/* - - - - - - - - - - - - - - - - - - - */_x000D_
_x000D_
var b = $.browser;_x000D_
console.log($.browser);    //    see console, working example of jQuery Plugin_x000D_
console.log($.browser.chrome);_x000D_
_x000D_
for (var x in b) {_x000D_
    if (x != 'init')_x000D_
        $('<tr />').append(_x000D_
            $('<th />', { text: x }),_x000D_
            $('<td />', { text: b[x] })_x000D_
        ).appendTo($('table'));_x000D_
}
_x000D_
table { border-collapse: collapse; }_x000D_
th, td { border: 1px solid; padding: .25em .5em; vertical-align: top; }_x000D_
th { text-align: right; }_x000D_
_x000D_
textarea { height: 500px; width: 100%; }
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<table></table>
_x000D_
_x000D_
_x000D_

Can anyone explain IEnumerable and IEnumerator to me?

IEnumerable implements GetEnumerator. When called, that method will return an IEnumerator which implements MoveNext, Reset and Current.

Thus when your class implements IEnumerable, you are saying that you can call a method (GetEnumerator) and get a new object returned (an IEnumerator) you can use in a loop such as foreach.

Are there any log file about Windows Services Status?

The most likely place to find this sort of information is in the event viewer (under Administrative tools in XP or run eventvwr) This is where most services log warnings errors etc.

How to embed a PDF viewer in a page?

Be sure to test any solution across different Reader preferences. A site visitor may have their browser set to open the PDF in Reader/Acrobat as opposed to the browser, e.g., by disabling the Acrobat plugin in Firefox..

I can't be sure of my results, because I have two different Acrobat plugins that Firefox recognizes due to my having different versions of Adobe Acrobat and Adobe Reader, but it does appear that you at least need to test what happens if a website visitor has their browser set to not open the PDF in the browser. It could be quite annoying when they look at what appears to be an otherwise usable web page and their browser is nagging them to open a PDF file that they think they didn't request. In some cases, the PDF file spontaneously opened in Adobe Reader, not the browser, and in other cases the browser threw up a dialog saying the file didn't exist.

I ran into such mismatches with iframe and object both, different issues for different code.

This is for simple HTML code. I haven't tried the suggested frameworks.

How to solve maven 2.6 resource plugin dependency?

If a download fails for some reason Maven will not try to download it within a certain time frame (it leaves a file with a timestamp).

To fix this you can either

  • Clear (parts of) your .m2 repo
  • Run maven with -U to force an update

ValueError: shape mismatch: objects cannot be broadcast to a single shape

This particular error implies that one of the variables being used in the arithmetic on the line has a shape incompatible with another on the same line (i.e., both different and non-scalar). Since n and the output of np.add.reduce() are both scalars, this implies that the problem lies with xm and ym, the two of which are simply your x and y inputs minus their respective means.

Based on this, my guess is that your x and y inputs have different shapes from one another, making them incompatible for element-wise multiplication.

** Technically, it's not that variables on the same line have incompatible shapes. The only problem is when two variables being added, multiplied, etc., have incompatible shapes, whether the variables are temporary (e.g., function output) or not. Two variables with different shapes on the same line are fine as long as something else corrects the issue before the mathematical expression is evaluated.

ReactJS - Does render get called any time "setState" is called?

Another reason for "lost update" can be the next:

  • If the static getDerivedStateFromProps is defined then it is rerun in every update process according to official documentation https://reactjs.org/docs/react-component.html#updating.
  • so if that state value comes from props at the beginning it is overwrite in every update.

If it is the problem then U can avoid setting the state during update, you should check the state parameter value like this

static getDerivedStateFromProps(props: TimeCorrectionProps, state: TimeCorrectionState): TimeCorrectionState {
   return state ? state : {disable: false, timeCorrection: props.timeCorrection};
}

Another solution is add a initialized property to state, and set it up in the first time (if the state is initialized to non null value.)

What does "res.render" do, and what does the html file look like?

What does res.render do and what does the html file look like?

res.render() function compiles your template (please don't use ejs), inserts locals there, and creates html output out of those two things.


Answering Edit 2 part.

// here you set that all templates are located in `/views` directory
app.set('views', __dirname + '/views');

// here you set that you're using `ejs` template engine, and the
// default extension is `ejs`
app.set('view engine', 'ejs');

// here you render `orders` template
response.render("orders", {orders: orders_json});

So, the template path is views/ (first part) + orders (second part) + .ejs (third part) === views/orders.ejs


Anyway, express.js documentation is good for what it does. It is API reference, not a "how to use node.js" book.

Checking letter case (Upper/Lower) within a string in Java

This is quite old and @SinkingPoint already gave a great answer above. Now, with functional idioms available in Java 8 we could give it one more twist. You would have two lambdas:

Function<String, Boolean> hasLowerCase = s -> s.chars().filter(c -> Character.isLowerCase(c)).count() > 0;
Function<String, Boolean> hasUpperCase = s -> s.chars().filter(c -> Character.isUpperCase(c)).count() > 0;

Then in code we could check password rules like this:

if (!hasUppercase.apply(password)) System.out.println("Must have an uppercase Character");
if (!hasLowercase.apply(password)) System.out.println("Must have a lowercase Character");

As to the other checks:

Function<String,Boolean> isAtLeast8 = s -> s.length() >= 8; //Checks for at least 8 characters
Function<String,Boolean> hasSpecial   = s -> !s.matches("[A-Za-z0-9 ]*");//Checks at least one char is not alpha numeric
Function<String,Boolean> noConditions = s -> !(s.contains("AND") || s.contains("NOT"));//Check that it doesn't contain AND or NOT

In some cases, it is arguable, whether creating the lambda adds value in terms of communicating intent, but the good thing about lambdas is that they are functional.

Delete ActionLink with confirm dialog

enter image description here MVC5 with delete dialogue & glyphicon. May work previous versions.

@Html.Raw(HttpUtility.HtmlDecode(@Html.ActionLink(" ", "Action", "Controller", new { id = model.id }, new { @class = "glyphicon glyphicon-trash", @OnClick = "return confirm('Are you sure you to delete this Record?');" }).ToHtmlString()))

Is it possible to decrypt SHA1

SHA1 is a cryptographic hash function, so the intention of the design was to avoid what you are trying to do.

However, breaking a SHA1 hash is technically possible. You can do so by just trying to guess what was hashed. This brute-force approach is of course not efficient, but that's pretty much the only way.

So to answer your question: yes, it is possible, but you need significant computing power. Some researchers estimate that it costs $70k - $120k.

As far as we can tell today, there is also no other way but to guess the hashed input. This is because operations such as mod eliminate information from your input. Suppose you calculate mod 5 and you get 0. What was the input? Was it 0, 5 or 500? You see, you can't really 'go back' in this case.

How to SELECT the last 10 rows of an SQL table which has no ID field?

You can use the "ORDER BY DESC" option, then put it back in the original order:

(SELECT * FROM tablename ORDER BY id DESC LIMIT 10) ORDER BY id;

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

If you have this issue with macOS, there is no easy way here: ( Especially, when you want to use R3.4. I have been there already.

R 3.4, rJava, macOS and even more mess

For R3.3 it's a little bit easier (R3.3 was compiled using different compiler).

R, Java, rJava and macOS adventures

The #include<iostream> exists, but I get an error: identifier "cout" is undefined. Why?

You need to specify the std:: namespace:

std::cout << .... << std::endl;;

Alternatively, you can use a using directive:

using std::cout;
using std::endl;

cout << .... << endl;

I should add that you should avoid these using directives in headers, since code including these will also have the symbols brought into the global namespace. Restrict using directives to small scopes, for example

#include <iostream>

inline void foo()
{
  using std::cout;
  using std::endl;
  cout << "Hello world" << endl;
}

Here, the using directive only applies to the scope of foo().

How to use GROUP BY to concatenate strings in MySQL?

The result is truncated to the maximum length that is given by the group_concat_max_len system variable, which has a default value of 1024 characters, so we first do:

SET group_concat_max_len=100000000;

and then, for example:

SELECT pub_id,GROUP_CONCAT(cate_id SEPARATOR ' ') FROM book_mast GROUP BY pub_id

Best way to determine user's locale within browser

I used all the answers and created a single line solution:

const getLanguage = () => navigator.userLanguage || (navigator.languages && navigator.languages.length && navigator.languages[0]) || navigator.language || navigator.browserLanguage || navigator.systemLanguage || 'en';

console.log(getLanguage());

How to make a local variable (inside a function) global

You could use module scope. Say you have a module called utils:

f_value = 'foo'

def f():
    return f_value

f_value is a module attribute that can be modified by any other module that imports it. As modules are singletons, any change to utils from one module will be accessible to all other modules that have it imported:

>> import utils
>> utils.f()
'foo'
>> utils.f_value = 'bar'
>> utils.f()
'bar'

Note that you can import the function by name:

>> import utils
>> from utils import f
>> utils.f_value = 'bar'
>> f()
'bar'

But not the attribute:

>> from utils import f, f_value
>> f_value = 'bar'
>> f()
'foo'

This is because you're labeling the object referenced by the module attribute as f_value in the local scope, but then rebinding it to the string bar, while the function f is still referring to the module attribute.

gnuplot : plotting data from multiple input files in a single graph

You may find that gnuplot's for loops are useful in this case, if you adjust your filenames or graph titles appropriately.

e.g.

filenames = "first second third fourth fifth"
plot for [file in filenames] file."dat" using 1:2 with lines

and

filename(n) = sprintf("file_%d", n)
plot for [i=1:10] filename(i) using 1:2 with lines

Why do I get an UnsupportedOperationException when trying to remove an element from a List?

Replace

List<String> list=Arrays.asList(split);

to

List<String> list = New ArrayList<>();
list.addAll(Arrays.asList(split));

or

List<String> list = new ArrayList<>(Arrays.asList(split));

or

List<String> list = new ArrayList<String>(Arrays.asList(split));

or (Better for Remove elements)

List<String> list = new LinkedList<>(Arrays.asList(split));

What does "Git push non-fast-forward updates were rejected" mean?

You need to merge and resolve the conflicts locally before you push your changes to remote repo/fork.

1) pull (fetch and merge)

$ git pull remote branch 

2) Push the changes

$ git push remote branch 

Still you have a quick choice to push forcibly by using --force option but should be avoided as it may result in changes loss or affect badly on other contributors.

Regex to replace everything except numbers and a decimal point

Try this:

document.getElementById(target).value = newVal.replace(/^\d+(\.\d{0,2})?$/, "");

Remove ALL styling/formatting from hyperlinks

if you state a.redLink{color:red;} then to keep this on hover and such add a.redLink:hover{color:red;} This will make sure no other hover states will change the color of your links

How to display length of filtered ng-repeat data

For Angular 1.3+ (credits to @Tom)

Use an alias expression (Docs: Angular 1.3.0: ngRepeat, scroll down to the Arguments section):

<div ng-repeat="person in data | filter:query as filtered">
</div>

For Angular prior to 1.3

Assign the results to a new variable (e.g. filtered) and access it:

<div ng-repeat="person in filtered = (data | filter: query)">
</div>

Display the number of results:

Showing {{filtered.length}} Persons

Fiddle a similar example. Credits go to Pawel Kozlowski

how to extract only the year from the date in sql server 2008?

the year function dose, like this:

select year(date_column) from table_name

Forward request headers from nginx proxy server

The problem is that '_' underscores are not valid in header attribute. If removing the underscore is not an option you can add to the server block:

underscores_in_headers on;

This is basically a copy and paste from @kishorer747 comment on @Fleshgrinder answer, and solution is from: https://serverfault.com/questions/586970/nginx-is-not-forwarding-a-header-value-when-using-proxy-pass/586997#586997

I added it here as in my case the application behind nginx was working perfectly fine, but as soon ngix was between my flask app and the client, my flask app would not see the headers any longer. It was kind of time consuming to debug.

iOS: how to perform a HTTP POST request?

Xcode 8 and Swift 3.0

Using URLSession:

 let url = URL(string:"Download URL")!
 let req = NSMutableURLRequest(url:url)
 let config = URLSessionConfiguration.default
 let session = URLSession(configuration: config, delegate: self, delegateQueue: OperationQueue.main)

 let task : URLSessionDownloadTask = session.downloadTask(with: req as URLRequest)
task.resume()

URLSession Delegate call:

func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {

}


func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, 
didWriteData bytesWritten: Int64, totalBytesWritten writ: Int64, totalBytesExpectedToWrite exp: Int64) {
                   print("downloaded \(100*writ/exp)" as AnyObject)

}

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL){

}

Using Block GET/POST/PUT/DELETE:

 let request = NSMutableURLRequest(url: URL(string: "Your API URL here" ,param: param))!,
        cachePolicy: .useProtocolCachePolicy,
        timeoutInterval:"Your request timeout time in Seconds")
    request.httpMethod = "GET"
    request.allHTTPHeaderFields = headers as? [String : String] 

    let session = URLSession.shared

    let dataTask = session.dataTask(with: request as URLRequest) {data,response,error in
        let httpResponse = response as? HTTPURLResponse

        if (error != nil) {
         print(error)
         } else {
         print(httpResponse)
         }

        DispatchQueue.main.async {
           //Update your UI here
        }

    }
    dataTask.resume()

Working fine for me.. try it 100% result guarantee

ORA-12505: TNS:listener does not currently know of SID given in connect descriptor (DBD ERROR: OCIServerAttach)

  1. Start oracleserviceorcl service. (From services in Task Manager)
  2. Set ORACLE_SID variable with orcl value. (In environment variables)

How can I resolve "Your requirements could not be resolved to an installable set of packages" error?

Were those dev-masters added automatically? Avoid them as unnecessary version constraints, for 'any suitable version' use "*", or "@dev" if you don't mind dev packages. My guess is that Entrust is the potential troublemaker.

Also, "minimum-stability": "stable" imposes additional constraints, and

"minimum-stability": "dev",
"prefer-stable": true

is more conflict-free, consider it a rule of thumb.

wget/curl large file from google drive

JULY 2020 - Windows users batch file solution

I would like to add a simple batch file solution for windows users, as I found only linux solutions and it took me several days to learn all this stuff for creating a solution for windows. So to save this work from others that may need it, here it is.

Tools you need

  1. wget for windows (small 5KB exe program, no need installation) Download it from here. https://eternallybored.org/misc/wget/

  2. jrepl for windows (small 117KB batch file program, no need installation) This tool is similar to linux sed tool. Download it from here: https://www.dostips.com/forum/viewtopic.php?t=6044

Assuming

%filename% - the file name you want the the download will be saved to.
%fileid% = google file id (as already was explained here before)

Batch code for downloading small file from google drive

wget -O "%filename%" "https://docs.google.com/uc?export=download&id=%fileid%"        

Batch code for downloading large file from google drive

set cookieFile="cookie.txt"
set confirmFile="confirm.txt"
   
REM downlaod cooky and message with request for confirmation
wget --quiet --save-cookies "%cookieFile%" --keep-session-cookies --no-check-certificate "https://docs.google.com/uc?export=download&id=%fileid%" -O "%confirmFile%"
   
REM extract confirmation key from message saved in confirm file and keep in variable resVar
jrepl ".*confirm=([0-9A-Za-z_]+).*" "$1" /F "%confirmFile%" /A /rtn resVar
   
REM when jrepl writes to variable, it adds carriage return (CR) (0x0D) and a line feed (LF) (0x0A), so remove these two last characters
set confirmKey=%resVar:~0,-2%
   
REM download the file using cookie and confirmation key
wget --load-cookies "%cookieFile%" -O "%filename%" "https://docs.google.com/uc?export=download&id=%fileid%&confirm=%confirmKey%"
   
REM clear temporary files 
del %cookieFile%
del %confirmFile%

Merge r brings error "'by' must specify uniquely valid columns"

Rather give names of the column on which you want to merge:

exporttab <- merge(x=dwd_nogap, y=dwd_gap, by.x='x1', by.y='x2', fill=-9999)

Create or write/append in text file

There is no such file open mode as "wr" in your code:

fopen("logs.txt", "wr") 

The file open modes in PHP http://php.net/manual/en/function.fopen.php is the same as in C: http://www.cplusplus.com/reference/cstdio/fopen/

There are the following main open modes "r" for read, "w" for write and "a" for append, and you cannot combine them. You can add other modifiers like "+" for update, "b" for binary. The new C standard adds a new standard subspecifier ("x"), supported by PHP, that can be appended to any "w" specifier (to form "wx", "wbx", "w+x" or "w+bx"/"wb+x"). This subspecifier forces the function to fail if the file exists, instead of overwriting it.

Besides that, in PHP 5.2.6, the 'c' main open mode was added. You cannot combine 'c' with 'a', 'r', 'w'. The 'c' opens the file for writing only. If the file does not exist, it is created. If it exists, it is neither truncated (as opposed to 'w'), nor the call to this function fails (as is the case with 'x'). 'c+' Open the file for reading and writing; otherwise it has the same behavior as 'c'.

Additionally, and in PHP 7.1.2 the 'e' option was added that can be combined with other modes. It set close-on-exec flag on the opened file descriptor. Only available in PHP compiled on POSIX.1-2008 conform systems.

So, for the task as you have described it, the best file open mode would be 'a'. It opens the file for writing only. It places the file pointer at the end of the file. If the file does not exist, it attempts to create it. In this mode, fseek() has no effect, writes are always appended.

Here is what you need, as has been already pointed out above:

fopen("logs.txt", "a") 

Simple calculations for working with lat/lon and km distance?

Interesting that I didn't see a mention of UTM coordinates.

https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system.

At least if you want to add km to the same zone, it should be straightforward (in Python : https://pypi.org/project/utm/ )

utm.from_latlon and utm.to_latlon.

Get Application Directory

For current Android application package:

public String getDataDir(Context context) throws Exception {
    return context.getPackageManager().getPackageInfo(context.getPackageName(), 0).applicationInfo.dataDir;
}

For any package:

public String getAnyDataDir(Context context, String packageName) throws Exception {
    return context.getPackageManager().getPackageInfo(packageName, 0).applicationInfo.dataDir;
}

Running sites on "localhost" is extremely slow

Try to enable the Bypass proxy server for local addresses. This works for all browsers installed (Firefox, Chrome, etc).

  1. Open Internet Explorer by clicking the Start button Picture of the Start button. In the search box, type Internet Explorer, and then, in the list of results, click Internet Explorer.

  2. Click the Tools button, and then click Internet Options.

  3. Click the Connections tab, and then click LAN settings.

  4. Select the Use a proxy server for your LAN check box.

  5. Select the Bypass proxy server for local addresses

How to disable Excel's automatic cell reference change after copy/paste?

This simple trick works: Copy and Paste. Do NOT cut and paste. After you paste, then reselect the part you copied and go to EDIT, slide down to CLEAR, and CLEAR CONTENTS.

SQL join on multiple columns in same tables

You want to join on condition 1 AND condition 2, so simply use the AND keyword as below

ON a.userid = b.sourceid AND a.listid = b.destinationid;

SASS :not selector

I tried re-creating this, and .someclass.notip was being generated for me but .someclass:not(.notip) was not, for as long as I did not have the @mixin tip() defined. Once I had that, it all worked.

http://sassmeister.com/gist/9775949

$dropdown-width: 100px;
$comp-tip: true;

@mixin tip($pos:right) {

}

@mixin dropdown-pos($pos:right) {
  &:not(.notip) {
    @if $comp-tip == true{
      @if $pos == right {
        top:$dropdown-width * -0.6;
        background-color: #f00;
        @include tip($pos:$pos);
      }
    }
  }
  &.notip {
    @if $pos == right {
      top: 0;
      left:$dropdown-width * 0.8;
      background-color: #00f;
    }
  }
}

.someclass { @include dropdown-pos(); }

EDIT: http://sassmeister.com/ is a good place to debug your SASS because it gives you error messages. Undefined mixin 'tip'. it what I get when I remove @mixin tip($pos:right) { }

Found 'OR 1=1/* sql injection in my newsletter database

It probably aimed to select all the informations in your table. If you use this kind of query (for example in PHP) :

mysql_query("SELECT * FROM newsletter WHERE email = '$email'");

The email ' OR 1=1/* will give this kind of query :

mysql_query("SELECT * FROM newsletter WHERE email = '' OR 1=1/*");

So it selects all the rows (because 1=1 is always true and the rest of the query is 'commented'). But it was not successful

  • if strings used in your queries are escaped
  • if you don't display all the queries results on a page...

What could cause java.lang.reflect.InvocationTargetException?

This exception is thrown if the underlying method(method called using Reflection) throws an exception.

So if the method, that has been invoked by reflection API, throws an exception (as for example runtime exception), the reflection API will wrap the exception into an InvocationTargetException.

Apache giving 403 forbidden errors

The server may need read permission for your home directory and .htaccess therein

Android file chooser

EDIT (02 Jan 2012):

I created a small open source Android Library Project that streamlines this process, while also providing a built-in file explorer (in case the user does not have one present). It's extremely simple to use, requiring only a few lines of code.

You can find it at GitHub: aFileChooser.


ORIGINAL

If you want the user to be able to choose any file in the system, you will need to include your own file manager, or advise the user to download one. I believe the best you can do is look for "openable" content in an Intent.createChooser() like this:

private static final int FILE_SELECT_CODE = 0;

private void showFileChooser() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT); 
    intent.setType("*/*"); 
    intent.addCategory(Intent.CATEGORY_OPENABLE);

    try {
        startActivityForResult(
                Intent.createChooser(intent, "Select a File to Upload"),
                FILE_SELECT_CODE);
    } catch (android.content.ActivityNotFoundException ex) {
        // Potentially direct the user to the Market with a Dialog
        Toast.makeText(this, "Please install a File Manager.", 
                Toast.LENGTH_SHORT).show();
    }
}

You would then listen for the selected file's Uri in onActivityResult() like so:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case FILE_SELECT_CODE:
        if (resultCode == RESULT_OK) {
            // Get the Uri of the selected file 
            Uri uri = data.getData();
            Log.d(TAG, "File Uri: " + uri.toString());
            // Get the path
            String path = FileUtils.getPath(this, uri);
            Log.d(TAG, "File Path: " + path);
            // Get the file instance
            // File file = new File(path);
            // Initiate the upload
        }
        break;
    }
    super.onActivityResult(requestCode, resultCode, data);
}

The getPath() method in my FileUtils.java is:

public static String getPath(Context context, Uri uri) throws URISyntaxException {
    if ("content".equalsIgnoreCase(uri.getScheme())) {
        String[] projection = { "_data" };
        Cursor cursor = null;

        try {
            cursor = context.getContentResolver().query(uri, projection, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow("_data");
            if (cursor.moveToFirst()) {
                return cursor.getString(column_index);
            }
        } catch (Exception e) {
            // Eat it
        }
    }
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
} 

Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sierra/Mojave?

You can give https://github.com/ersiner/osx-env-sync a try. It handles both command line and GUI apps from a single source and works withe the latest version of OS X (Yosemite).

You can use path substitutions and other shell tricks since what you write is regular bash script to be sourced by bash in the first place. No restrictions.. (Check osx-env-sync documentation and you'll understand how it achieves this.)

I answered a similar question here where you'll find more.

Using the grep and cut delimiter command (in bash shell scripting UNIX) - and kind of "reversing" it?

You don't need to change the delimiter to display the right part of the string with cut.

The -f switch of the cut command is the n-TH element separated by your delimiter : :, so you can just type :

 grep puddle2_1557936 | cut -d ":" -f2

Another solutions (adapt it a bit) if you want fun :

Using :

grep -oP 'puddle2_1557936:\K.*' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                                        
/home/rogers.williams/folderz/puddle2

or still with look around

grep -oP '(?<=puddle2_1557936:).*' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                                    
/home/rogers.williams/folderz/puddle2

or with :

perl -lne '/puddle2_1557936:(.*)/ and print $1' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'                                                      
/home/rogers.williams/folderz/puddle2

or using (thanks to glenn jackman)

ruby -F: -ane '/puddle2_1557936/ and puts $F[1]' <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'
/home/rogers.williams/folderz/puddle2

or with :

awk -F'puddle2_1557936:' '{print $2}'  <<< 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'
/home/rogers.williams/folderz/puddle2

or with :

python -c 'import sys; print(sys.argv[1].split("puddle2_1557936:")[1])' 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'
/home/rogers.williams/folderz/puddle2

or using only :

IFS=: read _ a <<< "puddle2_1557936:/home/rogers.williams/folderz/puddle2"
echo "$a"
/home/rogers.williams/folderz/puddle2

or using in a :

js<<EOF
var x = 'puddle2_1557936:/home/rogers.williams/folderz/puddle2'
print(x.substr(x.indexOf(":")+1))
EOF
/home/rogers.williams/folderz/puddle2

or using in a :

php -r 'preg_match("/puddle2_1557936:(.*)/", $argv[1], $m); echo "$m[1]\n";' 'puddle2_1557936:/home/rogers.williams/folderz/puddle2' 
/home/rogers.williams/folderz/puddle2

Is it safe to delete a NULL pointer?

delete performs the check anyway, so checking it on your side adds overhead and looks uglier. A very good practice is setting the pointer to NULL after delete (helps avoiding double deletion and other similar memory corruption problems).

I'd also love if delete by default was setting the parameter to NULL like in

#define my_delete(x) {delete x; x = NULL;}

(I know about R and L values, but wouldn't it be nice?)

Python error: AttributeError: 'module' object has no attribute

When you import lib, you're importing the package. The only file to get evaluated and run in this case is the 0 byte __init__.py in the lib directory.

If you want access to your function, you can do something like this from lib.mod1 import mod1 and then run the mod12 function like so mod1.mod12().

If you want to be able to access mod1 when you import lib, you need to put an import mod1 inside the __init__.py file inside the lib directory.

MySQL Foreign Key Error 1005 errno 150 primary key as foreign key

For me, I was trying to match up a regular indexed field in a child table, to a primary key in the parent table, and by default some MySQL frontend GUIs like Sequel Pro set the primary key as unsigned, so you have to make sure that the child table field is unsigned too (unless these fields might contain negative ints, then make sure they're both signed).

Rails - Could not find a JavaScript runtime?

if you already install nodejs from source for example, and execjs isn't recognizing it you might want to try this tip: https://coderwall.com/p/hyjdlw

In Jinja2, how do you test if a variable is undefined?

{% if variable is defined %} is true if the variable is None.

Since not is None is not allowed, that means that

{% if variable != None %}

is really your only option.

Redirecting a request using servlets and the "setHeader" method not working

Alternatively, you could try the following,

resp.setStatus(301);
resp.setHeader("Location", "index.jsp");
resp.setHeader("Connection", "close");

React proptype array with shape

This was my solution to protect against an empty array as well:

import React, { Component } from 'react';
import { arrayOf, shape, string, number } from 'prop-types';

ReactComponent.propTypes = {
  arrayWithShape: (props, propName, componentName) => {
    const arrayWithShape = props[propName]
    PropTypes.checkPropTypes({ arrayWithShape:
        arrayOf(
          shape({
            color: string.isRequired,
            fontSize: number.isRequired,
          }).isRequired
      ).isRequired
    }, {arrayWithShape}, 'prop', componentName);
    if(arrayWithShape.length < 1){
      return new Error(`${propName} is empty`)
    }
  }
}

Different CURRENT_TIMESTAMP and SYSDATE in oracle

SYSDATE returns the system date, of the system on which the database resides

CURRENT_TIMESTAMP returns the current date and time in the session time zone, in a value of datatype TIMESTAMP WITH TIME ZONE

execute this comman

    ALTER SESSION SET TIME_ZONE = '+3:0';

and it will provide you the same result.

Comparing strings in Java

In onclik function replace first line with this line u will definitely get right result.

if (passw1.getText().toString().equalsIgnoreCase("1234") && passw2.getText().toString().equalsIgnoreCase("1234")){

Remove a string from the beginning of a string

You can use regular expressions with the caret symbol (^) which anchors the match to the beginning of the string:

$str = preg_replace('/^bla_/', '', $str);

How do I set proxy for chrome in python webdriver?

This worked for me like a charm:

proxy = "localhost:8080"
desired_capabilities = webdriver.DesiredCapabilities.CHROME.copy()
desired_capabilities['proxy'] = {
    "httpProxy": proxy,
    "ftpProxy": proxy,
    "sslProxy": proxy,
    "noProxy": None,
    "proxyType": "MANUAL",
    "class": "org.openqa.selenium.Proxy",
    "autodetect": False
}

Make HTML5 video poster be same size as video itself

I was playing around with this and tried all solutions, eventually the solution I went with was a suggestion from Google Chrome's Inspector. If you add this to your CSS it worked for me:

video{
   object-fit: inherit;
}

Generate a heatmap in MatPlotLib using a scatter data set

Here's Jurgy's great nearest neighbour approach but implemented using scipy.cKDTree. In my tests it's about 100x faster.

enter image description here

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
from scipy.spatial import cKDTree


def data_coord2view_coord(p, resolution, pmin, pmax):
    dp = pmax - pmin
    dv = (p - pmin) / dp * resolution
    return dv


n = 1000
xs = np.random.randn(n)
ys = np.random.randn(n)

resolution = 250

extent = [np.min(xs), np.max(xs), np.min(ys), np.max(ys)]
xv = data_coord2view_coord(xs, resolution, extent[0], extent[1])
yv = data_coord2view_coord(ys, resolution, extent[2], extent[3])


def kNN2DDens(xv, yv, resolution, neighbours, dim=2):
    """
    """
    # Create the tree
    tree = cKDTree(np.array([xv, yv]).T)
    # Find the closest nnmax-1 neighbors (first entry is the point itself)
    grid = np.mgrid[0:resolution, 0:resolution].T.reshape(resolution**2, dim)
    dists = tree.query(grid, neighbours)
    # Inverse of the sum of distances to each grid point.
    inv_sum_dists = 1. / dists[0].sum(1)

    # Reshape
    im = inv_sum_dists.reshape(resolution, resolution)
    return im


fig, axes = plt.subplots(2, 2, figsize=(15, 15))
for ax, neighbours in zip(axes.flatten(), [0, 16, 32, 63]):

    if neighbours == 0:
        ax.plot(xs, ys, 'k.', markersize=5)
        ax.set_aspect('equal')
        ax.set_title("Scatter Plot")
    else:

        im = kNN2DDens(xv, yv, resolution, neighbours)

        ax.imshow(im, origin='lower', extent=extent, cmap=cm.Blues)
        ax.set_title("Smoothing over %d neighbours" % neighbours)
        ax.set_xlim(extent[0], extent[1])
        ax.set_ylim(extent[2], extent[3])

plt.savefig('new.png', dpi=150, bbox_inches='tight')

How do I size a UITextView to its content?

To make a dynamically sizing UITextView inside a UITableViewCell, I found the following combination works in Xcode 6 with the iOS 8 SDK:

  • Add a UITextView to a UITableViewCell and constrain it to the sides
  • Set the UITextView's scrollEnabled property to NO. With scrolling enabled, the frame of the UITextView is independent of its content size, but with scrolling disabled, there is a relationship between the two.
  • If your table is using the original default row height of 44 then it will automatically calculate row heights, but if you changed the default row height to something else, you may need to manually switch on auto-calculation of row heights in viewDidLoad:

    tableView.estimatedRowHeight = 150;
    tableView.rowHeight = UITableViewAutomaticDimension;
    

For read-only dynamically sizing UITextViews, that’s it. If you’re allowing users to edit the text in your UITextView, you also need to:

  • Implement the textViewDidChange: method of the UITextViewDelegate protocol, and tell the tableView to repaint itself every time the text is edited:

    - (void)textViewDidChange:(UITextView *)textView;
    {
        [tableView beginUpdates];
        [tableView endUpdates];
    }
    
  • And don’t forget to set the UITextView delegate somewhere, either in Storyboard or in tableView:cellForRowAtIndexPath:

PNG transparency issue in IE8

I had the same thing happen to a PNG with transparency that was set as the background-image of an <A> element with opacity applied.

The fix was to set the background-color of the <A> element.

So, the following:

filter: alpha(opacity=40);
-moz-opacity: 0.4;
-khtml-opacity: 0.4;
opacity: 0.4;
background-image: ...;

Turns into:

/* "Overwritten" by the background-image. However this fixes the IE7 and IE8 PNG-transparency-plus-opacity bug. */
background-color: #FFFFFF; 

filter: alpha(opacity=40);
-moz-opacity: 0.4;
-khtml-opacity: 0.4;
opacity: 0.4;
background-image: ...;

Expand a random range from 1–5 to 1–7

Would be cool if someone could give me feedback on this one, I used the JUNIT without assert Pattern because it's easy and fast to get it running in Eclipse, I could also have just defined a main method. By the way, I am assuming rand5 gives values 0-4, adding 1 would make it 1-5, same with rand7... So the discussion should be on the solution, it's distribution, not on wether it goes from 0-4 or 1-5...

package random;

import java.util.Random;

import org.junit.Test;

public class RandomTest {


    @Test
    public void testName() throws Exception {
        long times = 100000000;
        int indexes[] = new int[7];
        for(int i = 0; i < times; i++) {
            int rand7 = rand7();
            indexes[rand7]++;
        }

        for(int i = 0; i < 7; i++)
            System.out.println("Value " + i + ": " + indexes[i]);
    }


    public int rand7() {
        return (rand5() + rand5() + rand5() + rand5() + rand5() + rand5() + rand5()) % 7;
    }


    public int rand5() {
        return new Random().nextInt(5);
    }


}

When I run it, I get this result:

Value 0: 14308087
Value 1: 14298303
Value 2: 14279731
Value 3: 14262533
Value 4: 14269749
Value 5: 14277560
Value 6: 14304037

This seems like a very fair distribution, doesn't it?

If I add rand5() less or more times (where the amount of times is not divisible by 7), the distribution clearly shows offsets. For instance, adding rand5() 3 times:

Value 0: 15199685
Value 1: 14402429
Value 2: 12795649
Value 3: 12796957
Value 4: 14402252
Value 5: 15202778
Value 6: 15200250

So, this would lead to the following:

public int rand(int range) {
    int randomValue = 0;
    for(int i = 0; i < range; i++) {
        randomValue += rand5();
    }
    return randomValue % range;

}

And then, I could go further:

public static final int ORIGN_RANGE = 5;
public static final int DEST_RANGE  = 7;

@Test
public void testName() throws Exception {
    long times = 100000000;
    int indexes[] = new int[DEST_RANGE];
    for(int i = 0; i < times; i++) {
        int rand7 = convertRand(DEST_RANGE, ORIGN_RANGE);
        indexes[rand7]++;
    }

    for(int i = 0; i < DEST_RANGE; i++)
        System.out.println("Value " + i + ": " + indexes[i]);
}


public int convertRand(int destRange, int originRange) {
    int randomValue = 0;
    for(int i = 0; i < destRange; i++) {
        randomValue += rand(originRange);
    }
    return randomValue % destRange;

}


public int rand(int range) {
    return new Random().nextInt(range);
}

I tried this replacing the destRange and originRange with various values (even 7 for ORIGIN and 13 for DEST), and I get this distribution:

Value 0: 7713763
Value 1: 7706552
Value 2: 7694697
Value 3: 7695319
Value 4: 7688617
Value 5: 7681691
Value 6: 7674798
Value 7: 7680348
Value 8: 7685286
Value 9: 7683943
Value 10: 7690283
Value 11: 7699142
Value 12: 7705561

What I can conclude from here is that you can change any random to anyother by suming the origin random "destination" times. This will get a kind of gaussian distribution (being the middle values more likely, and the edge values more uncommon). However, the modulus of destination seems to distribute itself evenly across this gaussian distribution... It would be great to have feedback from a mathematician...

What is cool is that the cost is 100% predictable and constant, whereas other solutions cause a small probability of infinite loop...

Calling onclick on a radiobutton list using javascript

The other answers did not work for me, so I checked Telerik's official documentation it says you need to find the button and call the click() function:

function KeyPressed(sender, eventArgs) {
            var button = $find("<%= RadButton1.ClientID %>");
            button.click();
        }

RecyclerView inside ScrollView is not working

Actually the main purpose of the RecyclerView is to compensate for ListView and ScrollView. Instead of doing what you're actually doing: Having a RecyclerView in a ScrollView, I would suggest having only a RecyclerView that can handle many types of children.

change image opacity using javascript

I'm not sure if you can do this in every browser but you can set the css property of the specified img.
Try to work with jQuery which allows you to make css changes much faster and efficiently.
in jQuery you will have the options of using .animate(),.fadeTo(),.fadeIn(),.hide("slow"),.show("slow") for example.
I mean this CSS snippet should do the work for you:

img
{
opacity:0.4;
filter:alpha(opacity=40); /* For IE8 and earlier */
}

Also check out this website where everything further is explained:
http://www.w3schools.com/css/css_image_transparency.asp

Font from origin has been blocked from loading by Cross-Origin Resource Sharing policy

Chrome since ~Sep/Oct 2014 makes fonts subject to the same CORS checks as Firefox has done https://code.google.com/p/chromium/issues/detail?id=286681. There is a discussion on this in https://groups.google.com/a/chromium.org/forum/?fromgroups=#!topic/blink-dev/TT9D5-Zfnzw

Given that for fonts the browser may do a preflight check, then your S3 policy needs the cors request header as well. You can check your page in say Safari (which at present doesn't do CORS checking for fonts) and Firefox (that does) to double check this is the problem described.

See Stack overflow answer on Amazon S3 CORS (Cross-Origin Resource Sharing) and Firefox cross-domain font loading for the Amazon S3 CORS details.

NB in general because this used to apply to Firefox only, so it may help to search for Firefox rather than Chrome.

How do I test if a string is empty in Objective-C?

You have 2 methods to check whether the string is empty or not:

Let's suppose your string name is NSString *strIsEmpty.

Method 1:

if(strIsEmpty.length==0)
{
    //String is empty
}

else
{
    //String is not empty
}

Method 2:

if([strIsEmpty isEqualToString:@""])
{
    //String is empty
}

else
{
    //String is not empty
}

Choose any of the above method and get to know whether string is empty or not.

How to Replace dot (.) in a string in Java

return sentence.replaceAll("\s",".");

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". error

I can also confirm this error.

Workaround: is to use external maven inside m2eclipse, instead of it's embedded maven.

That is done in three steps:

1 Install maven on local machine (the test-machine was Ubuntu 10.10)

mvn --version

Apache Maven 2.2.1 (rdebian-4) Java version: 1.6.0_20 Java home: /usr/lib/jvm/java-6-openjdk/jre Default locale: de_DE, platform encoding: UTF-8 OS name: "linux" version: "2.6.35-32-generic" arch: "amd64" Family: "unix"

2 Run maven externally link how to run maven from console

> cd path-to-pom.xml
> mvn test
    [INFO] Scanning for projects...
    [INFO] ------------------------------------------------------------------------
    [INFO] Building Simple
    [INFO]    task-segment: [test]
    [INFO] ------------------------------------------------------------------------
    [...]
    [INFO] Surefire report directory: [...]/workspace/Simple/target/surefire-reports
    
    -------------------------------------------------------
     T E S T S
    -------------------------------------------------------
    Running net.tverrbjelke.experiment.MainAppTest
    Hello World
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.042 sec
    
    Results :
    
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
    
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESSFUL
    [INFO] ------------------------------------------------------------------------
    [...]

3 inside m2eclipse: switch from embedded maven to local maven

  • find out where local maven home installation dir is (mvn --version, or google for your MAVEN_HOME, for me this helped me that is /usr/share/maven2 )
  • in eclipse Menu->Window->Preferences->Maven->Installation-> enter that string. Then you should have switched to your new external maven.
  • then run your Project as e.g. "maven test".

The error-message should be gone.

What is the difference between match_parent and fill_parent?

Both, FILL_PARENT and MATCH_PARENT are the same properties. FILL_PARENT was deprecated in API level 8.

How do you overcome the HTML form nesting limitation?

In response to a question posted by Yar in a comment to his own answer, I present some JavaScript which will resize an iframe. For the case of a form button, it is safe to assume the iframe will be on the same domain. This is the code I use. You will have to alter the maths/constants for your own site:

function resizeIFrame(frame)
{
    try {
        innerDoc = ('contentDocument' in frame) ? frame.contentDocument : frame.contentWindow.document;
        if('style' in frame) {
            frame.style.width = Math.min(755, Math.ceil(innerDoc.body.scrollWidth)) + 'px';
            frame.style.height = Math.ceil(innerDoc.body.scrollHeight) + 'px';
        } else {
            frame.width = Math.ceil(innerDoc.body.scrollWidth);
            frame.height = Math.ceil(innerDoc.body.scrollHeight);
        }
    } catch(err) {
        window.status = err.message;
    }
}

Then call it like this:

<iframe ... frameborder="0" onload="if(window.parent && window.parent.resizeIFrame){window.parent.resizeIFrame(this);}"></iframe>

What's the quickest way to multiply multiple cells by another number?

Are you asking how to do it in excel or how to do it in a VBA application? If you just want to do it in excel, here is one way.

Git keeps prompting me for a password

git config credential.helper store

Note: While this is convenient, Git will store your credentials in clear text in a local file (.git-credentials) under your project directory (see below for the "home" directory). If you don't like this, delete this file and switch to using the cache option.

If you want Git to resume to asking you for credentials every time it needs to connect to the remote repository, you can run this command:

git config --unset credential.helper

To store the passwords in .git-credentials in your %HOME% directory as opposed to the project directory: use the --global flag

git config --global credential.helper store

How do I change an HTML selected option using JavaScript?

Change

document.getElementById('personlist').getElementsByTagName('option')[11].selected = 'selected'

to

document.getElementById('personlist').value=Person_ID;

In nodeJs is there a way to loop through an array without using array size?

Use Iterators...

var myarray = ['hello', ' hello again'];
processArray(myarray[Symbol.iterator](), () => {
    console.log('all done')
})
function processArray(iter, cb) {
    var curr = iter.next()
    if(curr.done)
        return cb()
    console.log(curr.value)
    processArray(iter, cb)
}

More in depth overview: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols

How can I change all input values to uppercase using Jquery?

Try like below,

$('input[type=text]').val (function () {
    return this.value.toUpperCase();
})

You should use input[type=text] instead of :input or input as I believe your intention are to operate on textbox only.

Why does C# XmlDocument.LoadXml(string) fail when an XML header is included?

I had the same problem when switching from absolute to relative path for my xml file. The following solves both loading and using relative source path issues. Using a XmlDataProvider, which is defined in xaml (should be possible in code too) :

    <Window.Resources>
    <XmlDataProvider 
        x:Name="myDP"
        x:Key="MyData"
        Source=""
        XPath="/RootElement/Element"
        IsAsynchronous="False"
        IsInitialLoadEnabled="True"                         
        debug:PresentationTraceSources.TraceLevel="High"  /> </Window.Resources>

The data provider automatically loads the document once the source is set. Here's the code :

        m_DataProvider = this.FindResource("MyData") as XmlDataProvider;
        FileInfo file = new FileInfo("MyXmlFile.xml");

        m_DataProvider.Document = new XmlDocument();
        m_DataProvider.Source = new Uri(file.FullName);

How to show git log history (i.e., all the related commits) for a sub directory of a git repo?

For tracking changes to a folder where the folder was moved, I started using:

git rev-list --all --pretty=oneline -- "*/foo/subfoo/*"

This isn't perfect as it will grab other folders with the same name, but if it is unique, then it seems to work.

Finding length of char array

You can do len = sizeof(a)/sizeof(*a) for any kind of array. But, you have initialized it as a[7] = {...} meaning its length is 7...

Remove all spaces from a string in SQL Server

Simply replace it;

SELECT REPLACE(fld_or_variable, ' ', '')

Edit: Just to clarify; its a global replace, there is no need to trim() or worry about multiple spaces for either char or varchar:

create table #t (
    c char(8),
    v varchar(8))

insert #t (c, v) values 
    ('a a'    , 'a a'    ),
    ('a a  '  , 'a a  '  ),
    ('  a a'  , '  a a'  ),
    ('  a a  ', '  a a  ')

select
    '"' + c + '"' [IN], '"' + replace(c, ' ', '') + '"' [OUT]
from #t  
union all select
    '"' + v + '"', '"' + replace(v, ' ', '') + '"'
from #t 

Result

IN             OUT
===================
"a a     "     "aa"
"a a     "     "aa"
"  a a   "     "aa"
"  a a   "     "aa"
"a a"          "aa"
"a a  "        "aa"
"  a a"        "aa"
"  a a  "      "aa"