Programs & Examples On #Packaged task

ORA-29283: invalid file operation ORA-06512: at "SYS.UTL_FILE", line 536

Assume file is already created in the predefined directory with name "table.txt"

  • 1) change the ownership for file :

    sudo chown username:username table.txt
  • 2) change the mode of the file

    sudo chmod 777 table.txt

Now, try it should work!

Pythonic way to combine FOR loop and IF statement

I personally think this is the prettiest version:

a = [2,3,4,5,6,7,8,9,0]
xyz = [0,12,4,6,242,7,9]
for x in filter(lambda w: w in a, xyz):
  print x


if you are very keen on avoiding to use lambda you can use partial function application and use the operator module (that provides functions of most operators).

from operator import contains
from functools import partial
print(list(filter(partial(contains, a), xyz)))

How to pass an array into a SQL Server stored procedure

As others have noted above, one way to do this is to convert your array to a string and then split the string inside SQL Server.

As of SQL Server 2016, there's a built-in way to split strings called


It returns a set of rows that you can insert into your temp table (or real table).

DECLARE @str varchar(200)
SET @str = "123;456;789;246;22;33;44;55;66"

would yield:


If you want to get fancier:

    thenumber int
DECLARE @str varchar(200)
SET @str = "123;456;789;246;22;33;44;55;66"


ORDER BY thenumber

would give you the same results as above (except the column name is "thenumber"), but sorted. You can use the table variable like any other table, so you can easily join it with other tables in the DB if you want.

Note that your SQL Server install has to be at compatibility level 130 or higher in order for the STRING_SPLIT() function to be recognized. You can check your compatibility level with the following query:

SELECT compatibility_level
FROM sys.databases WHERE name = 'yourdatabasename';

Most languages (including C#) have a "join" function you can use to create a string from an array.

int[] myarray = {22, 33, 44};
string sqlparam = string.Join(";", myarray);

Then you pass sqlparam as your parameter to the stored procedure above.

Creating an index on a table variable

The question is tagged SQL Server 2000 but for the benefit of people developing on the latest version I'll address that first.

SQL Server 2014

In addition to the methods of adding constraint based indexes discussed below SQL Server 2014 also allows non unique indexes to be specified directly with inline syntax on table variable declarations.

Example syntax for that is below.

/*SQL Server 2014+ compatible inline index syntax*/
C1 INT INDEX IX1 CLUSTERED, /*Single column indexes can be declared next to the column*/
       INDEX IX3 NONCLUSTERED(C1,C2) /*Example composite index*/

Filtered indexes and indexes with included columns can not currently be declared with this syntax however SQL Server 2016 relaxes this a bit further. From CTP 3.1 it is now possible to declare filtered indexes for table variables. By RTM it may be the case that included columns are also allowed but the current position is that they "will likely not make it into SQL16 due to resource constraints"

/*SQL Server 2016 allows filtered indexes*/
c1 INT NULL INDEX ix UNIQUE WHERE c1 IS NOT NULL /*Unique ignoring nulls*/

SQL Server 2000 - 2012

Can I create a index on Name?

Short answer: Yes.


A more detailed answer is below.

Traditional tables in SQL Server can either have a clustered index or are structured as heaps.

Clustered indexes can either be declared as unique to disallow duplicate key values or default to non unique. If not unique then SQL Server silently adds a uniqueifier to any duplicate keys to make them unique.

Non clustered indexes can also be explicitly declared as unique. Otherwise for the non unique case SQL Server adds the row locator (clustered index key or RID for a heap) to all index keys (not just duplicates) this again ensures they are unique.

In SQL Server 2000 - 2012 indexes on table variables can only be created implicitly by creating a UNIQUE or PRIMARY KEY constraint. The difference between these constraint types are that the primary key must be on non nullable column(s). The columns participating in a unique constraint may be nullable. (though SQL Server's implementation of unique constraints in the presence of NULLs is not per that specified in the SQL Standard). Also a table can only have one primary key but multiple unique constraints.

Both of these logical constraints are physically implemented with a unique index. If not explicitly specified otherwise the PRIMARY KEY will become the clustered index and unique constraints non clustered but this behavior can be overridden by specifying CLUSTERED or NONCLUSTERED explicitly with the constraint declaration (Example syntax)


As a result of the above the following indexes can be implicitly created on table variables in SQL Server 2000 - 2012.

|             Index Type              | Can be created on a table variable? |
| Unique Clustered Index              | Yes                                 |
| Nonunique Clustered Index           |                                     |
| Unique NCI on a heap                | Yes                                 |
| Non Unique NCI on a heap            |                                     |
| Unique NCI on a clustered index     | Yes                                 |
| Non Unique NCI on a clustered index | Yes                                 |

The last one requires a bit of explanation. In the table variable definition at the beginning of this answer the non unique non clustered index on Name is simulated by a unique index on Name,Id (recall that SQL Server would silently add the clustered index key to the non unique NCI key anyway).

A non unique clustered index can also be achieved by manually adding an IDENTITY column to act as a uniqueifier.

Uniqueifier INT NOT NULL IDENTITY(1,1),

But this is not an accurate simulation of how a non unique clustered index would normally actually be implemented in SQL Server as this adds the "Uniqueifier" to all rows. Not just those that require it.

ASP.NET custom error page - Server.GetLastError() is null

Looking more closely at my web.config set up, one of the comments in this post is very helpful

in 3.5 sp1 there is a new parameter redirectMode

So we can amend customErrors to add this parameter:

<customErrors mode="RemoteOnly" defaultRedirect="~/errors/GeneralError.aspx" redirectMode="ResponseRewrite" />

the ResponseRewrite mode allows us to load the «Error Page» without redirecting the browser, so the URL stays the same, and importantly for me, exception information is not lost.

Completely cancel a rebase

Use git rebase --abort. From the official Linux kernel documentation for git rebase:

git rebase --continue | --skip | --abort | --edit-todo

Finding the max/min value in an array of primitives using Java

The Google Guava library has min and max methods in its Chars, Ints, Longs, etc. classes.

So you can simply use:


No conversions are required and presumably it's efficiently implemented.

Ruby value of a hash key?

Hashes are indexed using the square brackets ([]). Just as arrays. But instead of indexing with the numerical index, hashes are indexed using either the string literal you used for the key, or the symbol. So if your hash is similar to

hash = { "key1" => "value1", "key2" => "value2" }

you can access the value with


or for

hash = { :key1 => "value1", :key2 => "value2"}

or the new format supported in Ruby 1.9

hash = { key1: "value1", key2: "value2" }

you can access the value with


How do we determine the number of days for a given month in python

Just for the sake of academic interest, I did it this way...

(dt.replace(month = dt.month % 12 +1, day = 1)-timedelta(days=1)).day

throwing exceptions out of a destructor

Throwing an exception out of a destructor is dangerous.
If another exception is already propagating the application will terminate.

#include <iostream>

class Bad
        // Added the noexcept(false) so the code keeps its original meaning.
        // Post C++11 destructors are by default `noexcept(true)` and
        // this will (by default) call terminate if an exception is
        // escapes the destructor.
        // But this example is designed to show that terminate is called
        // if two exceptions are propagating at the same time.
        ~Bad() noexcept(false)
            throw 1;
class Bad2
            throw 1;

int main(int argc, char* argv[])
        Bad   bad;
        std::cout << "Print This\n";

        if (argc > 3)
            Bad   bad; // This destructor will throw an exception that escapes (see above)
            throw 2;   // But having two exceptions propagating at the
                       // same time causes terminate to be called.
            Bad2  bad; // The exception in this destructor will
                       // cause terminate to be called.
        std::cout << "Never print this\n";


This basically boils down to:

Anything dangerous (i.e. that could throw an exception) should be done via public methods (not necessarily directly). The user of your class can then potentially handle these situations by using the public methods and catching any potential exceptions.

The destructor will then finish off the object by calling these methods (if the user did not do so explicitly), but any exceptions throw are caught and dropped (after attempting to fix the problem).

So in effect you pass the responsibility onto the user. If the user is in a position to correct exceptions they will manually call the appropriate functions and processes any errors. If the user of the object is not worried (as the object will be destroyed) then the destructor is left to take care of business.

An example:


The close() method can potentially throw an exception. The destructor calls close() if the file has been opened but makes sure that any exceptions do not propagate out of the destructor.

So if the user of a file object wants to do special handling for problems associated to closing the file they will manually call close() and handle any exceptions. If on the other hand they do not care then the destructor will be left to handle the situation.

Scott Myers has an excellent article about the subject in his book "Effective C++"


Apparently also in "More Effective C++"
Item 11: Prevent exceptions from leaving destructors

How to get streaming url from online streaming radio station

Shahar's answer was really helpful, but I found it quite tedious to do this all myself, so I made a nifty little Python program:

import re
import urllib2
import string
url1 = raw_input("Please enter a URL from Tunein Radio: ");
open_file = urllib2.urlopen(url1);
raw_file =;
API_key = re.findall(r"StreamUrl\":\"(.*?),",raw_file);
#print API_key;
#print "The API key is: " + API_key[0];
use_key = urllib2.urlopen(str(API_key[0]));
key_content =;
raw_stream_url = re.findall(r"Url\": \"(.*?)\"",key_content);
bandwidth = re.findall(r"Bandwidth\":(.*?),", key_content);
reliability = re.findall(r"lity\":(.*?),", key_content);
isPlaylist = re.findall(r"HasPlaylist\":(.*?),",key_content);
codec = re.findall(r"MediaType\": \"(.*?)\",", key_content);
tipe = re.findall(r"Type\": \"(.*?)\"", key_content);
total = 0
for element in raw_stream_url:
    total = total + 1
i = 0
print "I found " + str(total) + " streams.";
for element in raw_stream_url:
    print "Stream #" + str(i + 1);
    print "Stream stats:";
    print "Bandwidth: " + str(bandwidth[i]) + " kilobytes per second."
    print "Reliability: " + str(reliability[i]) + "%"
    print "HasPlaylist: " + str(isPlaylist[i]) + "."
    print "Stream codec: " + str(codec[i]) + "."
    print "This audio stream is " + tipe[i].lower() + "."
    print "Pure streaming URL: " + str(raw_stream_url[i]) + ".";
    i = i + 1
raw_input("Press enter to close TMUS.")

It's basically Shahar's solution automated.

Best way to store a key=>value array in JavaScript?

Objects inside an array:

var cars = [
        { "id": 1, brand: "Ferrari" }
        , { "id": 2, brand: "Lotus" }
        , { "id": 3, brand: "Lamborghini" }

CSS list item width/height does not work

Declare the a element as display: inline-block and drop the width and height from the li element.

Alternatively, apply a float: left to the li element and use display: block on the a element. This is a bit more cross browser compatible, as display: inline-block is not supported in Firefox <= 2 for example.

The first method allows you to have a dynamically centered list if you give the ul element a width of 100% (so that it spans from left to right edge) and then apply text-align: center.

Use line-height to control the text's Y-position inside the element.

jQuery delete all table rows except first

I think this is more readable given the intent:

$('someTableSelector').children( 'tr:not(:first)' ).remove();

Using children also takes care of the case where the first row contains a table by limiting the depth of the search.

If you had an TBODY element, you can do this:

$("someTableSelector > tbody:last").children().remove();

If you have THEAD or TFOOT elements you'll need to do something different.

jquery fill dropdown with json data

In most of the companies they required a common functionality for multiple dropdownlist for all the pages. Just call the functions or pass your (DropDownID,JsonData,KeyValue,textValue)




        var data = [{"stateid" : "1","statename" : "Mumbai"},
                    {"stateid" : "2","statename" : "Panjab"},
                    {"stateid" : "3","statename" : "Pune"},
                     {"stateid" : "4","statename" : "Nagpur"},
                     {"stateid" : "5","statename" : "kanpur"}];

        var Did=document.getElementById("DLState");

        function GetData(Did,data,valkey,textkey){
          var str= "";
          for (var i = 0; i <data.length ; i++){


            str+= "<option value='" + data[i][valkey] + "'>" + data[i][textkey] + "</option>";

        };    </script>

  <select id="DLState">

Is it better to use NOT or <> when comparing values?

The latter (<>), because the meaning of the former isn't clear unless you have a perfect understanding of the order of operations as it applies to the Not and = operators: a subtlety which is easy to miss.

JSON encode MySQL results

For example $result = mysql_query("SELECT * FROM userprofiles where NAME='TESTUSER' ");

1.) if $result is only one row.

$response = mysql_fetch_array($result);
echo json_encode($response);

2.) if $result is more than one row. You need to iterate the rows and save it to an array and return a json with array in it.

$rows = array();
if (mysql_num_rows($result) > 0) {
    while($r = mysql_fetch_assoc($result)) {
       $id = $r["USERID"];   //a column name (ex.ID) used to get a value of the single row at at time
       $rows[$id] = $r; //save the fetched row and add it to the array.
echo json_encode($rows);

Executing <script> elements inserted with .innerHTML

I needed something similar, but needed the script to remain or be re-created in the same spot as the original script, since my script targets the location of the script tag in the DOM to create/target elements. I also made the script recursive to make sure it also works if it is more than one level down.

NOTE: I use const here, if you have a older browser, just use var.

    window.exec_body_scripts = function(body_el) {
        // ref: based on Larry K's answer
        // Finds and executes scripts in a newly added element's body.
        // Needed since innerHTML does not run scripts.
        // Argument body_el is an element in the dom.
            type__Js = 'text/javascript',
            tagName__Script = 'script',
            tagName__Script__Upper = tagName__Script.toUpperCase();
        var scripts = [], script, i;
        function evalScript(elem) {
            var parent = elem.parentNode,
                data = (elem.text || elem.textContent || elem.innerHTML || ""),
                script = document.createElement(tagName__Script);

            script.type = type__Js;
            try {
                // doesn't work on ie...
            } catch (e) {
                // IE has funky script nodes
                script.text = data;
            // Make sure to re-insert the script at the same position
            // to make sure scripts that target their position
            // in the DOM function as expected.
            var parent = elem.parentNode;
            parent.insertBefore(script, elem);
        // Get all scripts (recursive)
        if (typeof (document.querySelectorAll) !== typeof (void 0)) {
            document.querySelectorAll('script').forEach((scr) => { if (!scr.type || scr.type.toLowerCase() === type__Js) scripts.push(scr); });
        else {
            var children_nodes = body_el.childNodes, child;
            for (i = 0; children_nodes[i]; i++) {
                child = children_nodes[i];
                if (
                    child.nodeName.toUpperCase() === tagName__Script__Upper
                        child.type.toLowerCase() === type__Js
                ) {
                // Recursive call
        for (i = 0; scripts[i]; i++) {

Check if the number is integer

In R, whether a number is numeric or integer can be determined by class function. Generally all numbers are stored as numeric and to explicitly define a number as integer we need to specify 'L' after the number.


x <- 1


[1] "numeric"

x <- 1L


[1] "integer"

I hope this is what was needed. Thanks :)

How to interactively (visually) resolve conflicts in SourceTree / git

I'm using SourceTree along with TortoiseMerge/Diff, which is very easy and convinient diff/merge tool.

If you'd like to use it as well, then:

  1. Get standalone version of TortoiseMerge/Diff (quite old, since it doesn't ship standalone since version 1.6.7 of TortosieSVN, that is since July 2011). Links and details in this answer.

  2. Unzip TortoiseIDiff.exe and TortoiseMerge.exe to any folder (c:\Program Files (x86)\Atlassian\SourceTree\extras\ in my case).

  3. In SourceTree open Tools > Options > Diff > External Diff / Merge. Select TortoiseMerge in both dropdown lists.

  4. Hit OK and point SourceTree to your location of TortoiseIDiff.exe and TortoiseMerge.exe.

After that, you can select Resolve Conflicts > Launch External Merge Tool from context menu on each conflicted file in your local repository. This will open up TortoiseMerge, where you can easily deal with all the conflicts, you have. Once finished, simply close TortoiseMerge (you don't even need to save changes, this will probably be done automatically) and after few seconds SourceTree should handle that gracefully.

The only problem is, that it automatically creates backup copy, even though proper option is unchecked.

Getting mouse position in c#

Initialize the current cursor. Use it to get the position of X and Y

this.Cursor = new Cursor(Cursor.Current.Handle);
int posX = Cursor.Position.X;
int posY = Cursor.Position.Y;

How to format JSON in notepad++

Always google so you can locate the latest package for both NPP and NPP Plugins.

I googled "notepad++ 64bit". Downloaded the free latest version at Notepad++ (64-bit) - Free download and software. Installed notepad++ by double-click on npp.?.?.?.Installer.x64.exe, installed the .exe to default Windows 64bit path which is, "C:\Program Files".

Then, I googled "notepad++ 64 json viewer plug". Knowing SourceForge.Net is a renowned download site, downloaded JSToolNpp [email protected]. I unzipped and copied JSMinNPP.dll to notePad++ root dir.

I loaded my newly installed notepad++ 64bit. I went to Settings and selected [import plug-in]. I pointed to the location of JSMinNPP.dll and clicked open.

I reloaded notepad++, went to PlugIns menu. To format one-line json string to multi-line json doc, I clicked JSTool->JSFormat or reverse multi-line json doc to one-line json string by JSTool->JSMin (json-Minified)!

All items are in this picture.

Insert Data Into Temp Table with Query

SQL Server R2 2008 needs the AS clause as follows:

INTO #temp
    SELECT col1, col2
    FROM table1
) AS x

The query failed without the AS x at the end.


It's also needed when using SS2016, had to add as t to the end.

 Select * into #result from (SELECT * FROM  #temp where [id] = @id) as t //<-- as t

Uncaught Invariant Violation: Too many re-renders. React limits the number of renders to prevent an infinite loop

I suspect that the problem lies in the fact that you are calling your state setter immediately inside the function component body, which forces React to re-invoke your function again, with the same props, which ends up calling the state setter again, which triggers React to call your function again.... and so on.

const SingInContainer = ({ message, variant}) => {
    const [open, setSnackBarState] = useState(false);
    const handleClose = (reason) => {
        if (reason === 'clickaway') {


    if (variant) {
        setSnackBarState(true); // HERE BE DRAGONS
    return (

Instead, I recommend you just conditionally set the default value for the state property using a ternary, so you end up with:

const SingInContainer = ({ message, variant}) => {
    const [open, setSnackBarState] = useState(variant ? true : false); 
                                  // or useState(!!variant); 
                                  // or useState(Boolean(variant));
    const handleClose = (reason) => {
        if (reason === 'clickaway') {


    return (

Comprehensive Demo

See this demo for a comprehensive demo of it working, plus the broken component you had, and you can toggle between the two.

How to access the local Django webserver from outside world

Pick one or more from:

  • Your application isn't successfully listening on the intended IP:PORT
    • Because you haven't configured it successfully
    • Because the user doesn't have permission to
  • Your application is listening successfully on the intended IP:PORT, but clients can't reach it because
    • The server local iptables prevents it.
    • A firewall prevents it.

So, you can check that your application is listening successfully by running lsof -i as root on the machine and look for a python entry with the corresponding port you've specified.

Non-root users generally cannot bind to ports < 1024.

You'll need to look at iptables -nvL to see if there's a rule that would prevent access to the ip:port that you are trying to bind your application to.

If there is an upstream firewall and you don't know much about it, you'll need to talk to your network administrators.

beyond top level package error in relative import

if you have an in an upper folder, you can initialize the import as import file/path as alias in that init file. Then you can use it on lower scripts as:

import alias

SQL Server Jobs with SSIS packages - Failed to decrypt protected XML node "DTS:Password" with error 0x8009000B

It is because creator of the SSIS packages is someone else and other person is executing the packages.

If suppose A person has created SSIS packages and B person is trying to execute than the above error comes.

You can solve the error by changing creator name from package properties from A to B.

Thanks, Kiran Sagar

How do I define a method which takes a lambda as a parameter in Java 8?

Lambdas are purely a call-site construct: the recipient of the lambda does not need to know that a Lambda is involved, instead it accepts an Interface with the appropriate method.

In other words, you define or use a functional interface (i.e. an interface with a single method) that accepts and returns exactly what you want.

For this Java 8 comes with a set of commonly-used interface types in java.util.function (thanks to Maurice Naftalin for the hint about the JavaDoc).

For this specific use case there's java.util.function.IntBinaryOperator with a single int applyAsInt(int left, int right) method, so you could write your method like this:

static int method(IntBinaryOperator op){
    return op.applyAsInt(5, 10);

But you can just as well define your own interface and use it like this:

public interface TwoArgIntOperator {
    public int op(int a, int b);

static int method(TwoArgIntOperator operator) {
    return operator.op(5, 10);

Using your own interface has the advantage that you can have names that more clearly indicate the intent.

Setting the height of a SELECT in IE

You can use a replacement: jQuery Chosen. It looks pretty awesome.

WRONGTYPE Operation against a key holding the wrong kind of value php

Redis supports 5 data types. You need to know what type of value that a key maps to, as for each data type, the command to retrieve it is different.

Here are the commands to retrieve key value:

  • if value is of type string -> GET <key>
  • if value is of type hash -> HGETALL <key>
  • if value is of type lists -> lrange <key> <start> <end>
  • if value is of type sets -> smembers <key>
  • if value is of type sorted sets -> ZRANGEBYSCORE <key> <min> <max>

Use the TYPE command to check the type of value a key is mapping to:

  • type <key>

HTML select drop-down with an input field

You can use input text with "list" attribute, which refers to the datalist of values.

<input type="text" name="city" list="cityname">_x000D_
    <datalist id="cityname">_x000D_
      <option value="Boston">_x000D_
      <option value="Cambridge">_x000D_

This creates a free text input field that also has a drop-down to select predefined choices. Attribution for example and more information:

How can I execute Python scripts using Anaconda's version of Python?

Set your python path to the Anaconda version instead

Windows has a built-in dialog for changing environment variables (following guide applies to XP classical view): Right-click the icon for your machine (usually located on your Desktop and called “My Computer”) and choose Properties there. Then, open the Advanced tab and click the Environment Variables button.

In short, your path is:

My Computer ? Properties ? Advanced ? Environment Variables In this dialog, you can add or modify User and System variables. To change System variables, you need non-restricted access to your machine (i.e. Administrator rights).

Find your PATH variable and add the location of your Anaconda directory.

Example of someone doing it here: How to add to the PYTHONPATH in Windows, so it finds my modules/packages? Make sure that you sub path out for the Anaconda file though.

Throwing multiple exceptions in a method of an interface in java

You can declare as many Exceptions as you want for your interface method. But the class you gave in your question is invalid. It should read

public class MyClass implements MyInterface {
  public void find(int x) throws A_Exception, B_Exception{

Then an interface would look like this

public interface MyInterface {
  void find(int x) throws A_Exception, B_Exception;

Hiding a sheet in Excel 2007 (with a password) OR hide VBA code in Excel

Here is what you do in Excel 2003:

  1. In your sheet of interest, go to Format -> Sheet -> Hide and hide your sheet.
  2. Go to Tools -> Protection -> Protect Workbook, make sure Structure is selected, and enter your password of choice.

Here is what you do in Excel 2007:

  1. In your sheet of interest, go to Home ribbon -> Format -> Hide & Unhide -> Hide Sheet and hide your sheet.
  2. Go to Review ribbon -> Protect Workbook, make sure Structure is selected, and enter your password of choice.

Once this is done, the sheet is hidden and cannot be unhidden without the password. Make sense?

If you really need to keep some calculations secret, try this: use Access (or another Excel workbook or some other DB of your choice) to calculate what you need calculated, and export only the "unclassified" results to your Excel workbook.

Principal Component Analysis (PCA) in Python

UPDATE: matplotlib.mlab.PCA is since release 2.2 (2018-03-06) indeed deprecated.

The library matplotlib.mlab.PCA (used in this answer) is not deprecated. So for all the folks arriving here via Google, I'll post a complete working example tested with Python 2.7.

Use the following code with care as it uses a now deprecated library!

from matplotlib.mlab import PCA
import numpy
data = numpy.array( [[3,2,5], [-2,1,6], [-1,0,4], [4,3,4], [10,-5,-6]] )
pca = PCA(data)

Now in `pca.Y' is the original data matrix in terms of the principal components basis vectors. More details about the PCA object can be found here.

>>> pca.Y
array([[ 0.67629162, -0.49384752,  0.14489202],
   [ 1.26314784,  0.60164795,  0.02858026],
   [ 0.64937611,  0.69057287, -0.06833576],
   [ 0.60697227, -0.90088738, -0.11194732],
   [-3.19578784,  0.10251408,  0.00681079]])

You can use matplotlib.pyplot to draw this data, just to convince yourself that the PCA yields "good" results. The names list is just used to annotate our five vectors.

import matplotlib.pyplot
names = [ "A", "B", "C", "D", "E" ]
matplotlib.pyplot.scatter(pca.Y[:,0], pca.Y[:,1])
for label, x, y in zip(names, pca.Y[:,0], pca.Y[:,1]):
    matplotlib.pyplot.annotate( label, xy=(x, y), xytext=(-2, 2), textcoords='offset points', ha='right', va='bottom' )

Looking at our original vectors we'll see that data[0] ("A") and data[3] ("D") are rather similar as are data[1] ("B") and data[2] ("C"). This is reflected in the 2D plot of our PCA transformed data.

PCA result plot

What is the difference between @Inject and @Autowired in Spring Framework? Which one to use under what condition?

The key difference(noticed when reading the Spring Docs) between @Autowired and @Inject is that, @Autowired has the 'required' attribute while the @Inject has no 'required' attribute.

How to know which is running in Jupyter notebook?

Assuming you have the wrong backend system you can change the backend kernel by creating a new or editing the existing kernel.json in the kernels folder of your jupyter data path jupyter --paths. You can have multiple kernels (R, Python2, Python3 (+virtualenvs), Haskell), e.g. you can create an Anaconda specific kernel:

$ <anaconda-path>/bin/python3 -m ipykernel install --user --name anaconda --display-name "Anaconda"

Should create a new kernel:


    "argv": [ "<anaconda-path>/bin/python3", "-m", "ipykernel", "-f", "{connection_file}" ],
    "display_name": "Anaconda",
    "language": "python"

You need to ensure ipykernel package is installed in the anaconda distribution.

This way you can just switch between kernels and have different notebooks using different kernels.

slideToggle JQuery right to left

Try this

$('.slidingDiv').toggle("slide", {direction: "right" }, 1000);

How to delete session cookie in Postman?

Manually deleting it in the chrome browser removes the cookie from Postman.

In your chrome browser go to chrome://settings/cookies

Find the cookie and delete it

Edit: As per Max890 comment below (in my version of Google Chrome (ver 63)) this is now chrome://settings/content/cookies Then go to "See all cookies and site data"

Update for Google Chrome 79.0.3945.88


Correct way to pass multiple values for same parameter name in GET request

Indeed, there is no defined standard. To support that information, have a look at wikipedia, in the Query String chapter. There is the following comment:

While there is no definitive standard, most web frameworks allow multiple values to be associated with a single field.[3][4]

Furthermore, when you take a look at the RFC 3986, in section 3.4 Query, there is no definition for parameters with multiple values.

Most applications use the first option you have shown: http://server/action?id=a&id=b. To support that information, take a look at this Stackoverflow link, and this MSDN link regarding ASP.NET applications, which use the same standard for parameters with multiple values.

However, since you are developing the APIs, I suggest you to do what is the easiest for you, since the caller of the API will not have much trouble creating the query string.

Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privileges?

I had the same problem and it took a lot of reading SO posts and Google's documentation. I finally found this from the Cloud SQL FAQ:

Google Cloud SQL does not support SUPER privileges, which means that GRANT ALL PRIVILEGES statements will not work. As an alternative, you can use GRANT ALL ON `%`.*

Hello World in Python

In python 3.x. you use

print("Hello, World")

In Python 2.x. you use

print "Hello, World!"

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

I had this same problem because I bought a CSS template and it grabbed a javascript an external javascript file through I went to that page in my browser and then changed it to https://whatever... using SSL and it worked, so in my HTML javascript tag I just changed the URL to use https instead of http and it worked.

SQL "select where not in subquery" returns no results

Just off the top of my head...

select c.commonID, t1.commonID, t2.commonID
from Common c
     left outer join Table1 t1 on t1.commonID = c.commonID
     left outer join Table2 t2 on t2.commonID = c.commonID
where t1.commonID is null 
     and t2.commonID is null

I ran a few tests and here were my results w.r.t. @patmortech's answer and @rexem's comments.

If either Table1 or Table2 is not indexed on commonID, you get a table scan but @patmortech's query is still twice as fast (for a 100K row master table).

If neither are indexed on commonID, you get two table scans and the difference is negligible.

If both are indexed on commonID, the "not exists" query runs in 1/3 the time.

PHP passing $_GET in linux command prompt

I don't have a php-cgi binary on Ubuntu, so I did this:

% alias php-cgi="php -r '"'parse_str(implode("&", array_slice($argv, 2)), $_GET); include($argv[1]);'"' --"
% php-cgi test1.php foo=123
You set foo to 123.

%cat test1.php
<html>You set foo to <?php print $_GET['foo']?>.</html>

How to find index of all occurrences of element in array?

["a", "b", "a", "b"]
   .map((val, index) => ({ val, index }))
   .filter(({val, index}) => val === "a")
   .map(({val, index}) => index)

=> [0, 2]

Latex - Change margins of only a few pages

A slight modification of this to change the \voffset works for me:


And then put your figures in a \begin{changemargin}{-1cm}...\end{changemargin} environment.

Enable vertical scrolling on textarea

Here's your CSS

  width: 200px;
  height: 300px;
  overflow-y: auto;

Reading a text file with SQL Server

BULK INSERT dbo.temp 

FROM 'c:\temp\file.txt' --- path file in db server 



it work for me but save as by editplus to ansi encoding for multilanguage

Disabling swap files creation in vim

I agree with those who question why vim needs all this 'disaster recovery' stuff when no other text editors bother with it. I don't want vim creating ANY extra files in the edited file's directory when I'm editing it, thank you very much. To that end, I have this in my _vimrc to disable swap files, and move irritating 'backup' files to the Temp dir:

" Uncomment below to prevent 'tilde backup files' (eg. myfile.txt~) from being created
"set nobackup

" Uncomment below to cause 'tilde backup files' to be created in a different dir so as not to clutter up the current file's directory (probably a better idea than disabling them altogether)
set backupdir=C:\Windows\Temp

" Uncomment below to disable 'swap files' (eg. .myfile.txt.swp) from being created
set noswapfile

Java: How to read a text file

Using Java 7 to read files with NIO.2

Import these packages:

import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

This is the process to read a file:

Path file = Paths.get("C:\\Java\\file.txt");

if(Files.exists(file) && Files.isReadable(file)) {

    try {
        // File reader
        BufferedReader reader = Files.newBufferedReader(file, Charset.defaultCharset());

        String line;
        // read each line
        while((line = reader.readLine()) != null) {
            // tokenize each number
            StringTokenizer tokenizer = new StringTokenizer(line, " ");
            while (tokenizer.hasMoreElements()) {
                // parse each integer in file
                int element = Integer.parseInt(tokenizer.nextToken());
    } catch (Exception e) {

To read all lines of a file at once:

Path file = Paths.get("C:\\Java\\file.txt");
List<String> lines = Files.readAllLines(file, StandardCharsets.UTF_8);

How to write a switch statement in Ruby

In Ruby 2.0, you can also use lambdas in case statements, as follows:

is_even = ->(x) { x % 2 == 0 }

case number
when 0 then puts 'zero'
when is_even then puts 'even'
else puts 'odd'

You can also create your own comparators easily using a Struct with a custom ===

Moddable = do
  def ===(numeric)
    numeric % n == 0

mod4 =
mod3 =

case number
when mod4 then puts 'multiple of 4'
when mod3 then puts 'multiple of 3'

(Example taken from "Can procs be used with case statements in Ruby 2.0?".)

Or, with a complete class:

class Vehicle
  def ===(another_vehicle)
    self.number_of_wheels == another_vehicle.number_of_wheels

four_wheeler = 4
two_wheeler = 2

case vehicle
when two_wheeler
  puts 'two wheeler'
when four_wheeler
  puts 'four wheeler'

(Example taken from "How A Ruby Case Statement Works And What You Can Do With It".)

How can I show an image using the ImageView component in javafx and fxml?

If you want to use FXML, you should separate the controller (like you were doing with the SampleController). Then your fx:controller in your FXML should point to that.

Probably you are missing the initialize method in your controller, which is part of the Initializable interface. This method is called after the FXML is loaded, so I recommend you to set your image there.

Your SampleController class must be something like this:

public class SampleController implements Initializable {

    private ImageView imageView;

    public void initialize(URL location, ResourceBundle resources) {
        File file = new File("src/Box13.jpg");
        Image image = new Image(file.toURI().toString());

I tested here and it's working.

How to smooth a curve in the right way?

Fitting a moving average to your data would smooth out the noise, see this this answer for how to do that.

If you'd like to use LOWESS to fit your data (it's similar to a moving average but more sophisticated), you can do that using the statsmodels library:

import numpy as np
import pylab as plt
import statsmodels.api as sm

x = np.linspace(0,2*np.pi,100)
y = np.sin(x) + np.random.random(100) * 0.2
lowess = sm.nonparametric.lowess(y, x, frac=0.1)

plt.plot(x, y, '+')
plt.plot(lowess[:, 0], lowess[:, 1])

Finally, if you know the functional form of your signal, you could fit a curve to your data, which would probably be the best thing to do.

Keep only first n characters in a string?

You could try:

myString.substring(0, 8);

Get last 5 characters in a string

I opened this thread looking for a quick solution to a simple question, but I found that the answers here were either not helpful or overly complicated. The best way to get the last 5 chars of a string is, in fact, to use the Right() method. Here is a simple example:

Dim sMyString, sLast5 As String

sMyString = "I will be going to school in 2011!"
sLast5 = Right(sMyString, - 5)
MsgBox("sLast5 = " & sLast5)

If you're getting an error then there is probably something wrong with your syntax. Also, with the Right() method you don't need to worry much about going over or under the string length. In my example you could type in 10000 instead of 5 and it would just MsgBox the whole string, or if sMyString was NULL or "", the message box would just pop up with nothing.

ERROR: SQLSTATE[HY000] [2002] No connection could be made because the target machine actively refused it

If the WAMP icon is Orange then one of the services has not started.

In your case it looks like MySQL has not started as you are getting the message that indicates there is no server running and therefore listening for requests.

Look at the mysql log and if that tells you nothing look at the Windows event log, in the Windows -> Applications section. Error messages in there are pretty good at identifying the cause of MySQL failing to start.

Sometimes this is caused by a my.ini file from another install being picked up by WAMPServers MySQL, normally in the \windows or \windows\system32 folders. Do a search for 'my.ini' and 'my.cnf' and if you find one of these anywhere outside of the \wamp.... folder structure then delete it, or at least rename it so it wont be found. Then restart the MySQL service.

How to set DialogFragment's width and height?

You can below code to set layout width and height from java.

final AlertDialog alertDialog  = alertDialogBuilder.create();
final WindowManager.LayoutParams WMLP = alertDialog.getWindow().getAttributes();

WMLP.gravity = Gravity.TOP;
WMLP.y = mActionBarHeight;
WMLP.x = getResources().getDimensionPixelSize(R.dimen.unknown_image_width);


Dynamic classname inside ngClass in angular 2

This one should work

<button [ngClass]="{[namespace + '-mybutton']: type === 'mybutton'}"></button>

but Angular throws on this syntax. I'd consider this a bug. See also

The others are invalid. You can't use [] together with {{}}. Either one or the other. {{}} binds the result stringified which doesn't lead to the desired result in this case because an object needs to be passed to ngClass.

Plunker example

As workaround the syntax shown by @A_Sing or

<button [ngClass]="type === 'mybutton' ? namespace + '-mybutton' : ''"></button>

can be used.

What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?

Arrow functions which is denoted by symbol (=>) helps you to create anonymous functions and methods. That leads to more shorter syntax. For example, below is a simple “Add” function which returns addition of two numbers.

function Add(num1 , num2 ){
return num1 + num2;

The above function becomes shorter by using “Arrow” syntax as shown below.

enter image description here

Above code has two parts as shown in the above diagram: -

Input: — This section specifies the input parameters to the anonymous function.

Logic: — This section comes after the symbol “=>”. This section has the logic of the actual function.

Many developers think that arrow function makes your syntax shorter, simpler and thus makes your code readable.

If you believe the above sentence, then let me assure you it’s a myth. If you think for a moment a properly written function with name is much readable than cryptic functions created in one line using an arrow symbol.

The main use of arrow function is to ensure that code runs in the callers context.

See the below code in which have a global variable "context" defined , this global variable is accessed inside a function "SomeOtherMethod" which is called from other method "SomeMethod".

This "SomeMethod" has local "context" variable. Now because "SomeOtherMethod" is called from ""SomeMethod" we expect it to display "local context" , but it displays "global context".

var context = “global context”;

function SomeOtherMethod(){

function SomeMethod(){
this.context = “local context”;

var instance = new SomeMethod();

But if replace the call by using Arrow function it will display "local context".

var context = "global context";

    function SomeMethod(){
        this.context = "local context";
        SomeOtherMethod = () => {
    var instance = new SomeMethod();

I would encourage you to read this link ( Arrow function in JavaScript ) which explain all the scenarios of javascript context and in which scenarios the callers context is not respected.

You can also see the demonstration of Arrow function with javascript in this youtube video which demonstrates practically the term Context.

Why an inline "background-image" style doesn't work in Chrome 10 and Internet Explorer 8?

As c-smile mentioned: Just need to remove the apostrophes in the url():

<div style="background-image: url("></div>

Demo here

What HTTP status response code should I use if the request is missing a required parameter?

For those interested, Spring MVC (3.x at least) returns a 400 in this case, which seems wrong to me.

I tested several Google URLs ( and removed required parameters, and they generally return a 404 in this case.

I would copy Google.

What's the valid way to include an image with no src?

<img src="invis.gif" />

Where invis.gif is a single pixel transparent gif. This won't break in future browser versions and has been working in legacy browsers since the '90s.

png should work too but in my tests, the gif was 43 bytes and the png was 167 bytes so the gif won.

p.s. don't forget an alt tag, validators like them too.

Open a URL without using a browser from a batch file

If all you want is to request the URL and if it needs to be done from batch file, without anything outside of the OS, this can help you:

@if (@This==@IsBatch) @then
@echo off
rem **** batch zone *********************************************************

    setlocal enableextensions disabledelayedexpansion

    rem The batch file will delegate all the work to the script engine
    if not "%~1"=="" (
        wscript //E:JScript "%~dpnx0" %1

    rem End of batch file area. Ensure the batch file ends execution
    rem before reaching the JavaScript zone
    exit /b


// **** JavaScript zone *****************************************************
// Instantiate the needed component to make URL queries
var http = WScript.CreateObject('Msxml2.XMLHTTP.6.0');

// Retrieve the URL parameter
var url = WScript.Arguments.Item(0)

// Make the request"GET", url, false);

// All done. Exit

It is just a hybrid batch/JavaScript file and is saved as callurl.cmd and called as callurl "". It will do what you ask for. No error check, no post, just a skeleton.

If it is possible to use something outside of the OS, wget or curl are available as Windows executables and are the best options available.

If you are limited by some kind of security policy, you can get the Internet Information Services (IIS) 6.0 Resource Kit Tools. It includes tinyget and wfetch tools that can do what you need.

How to list all tags along with the full message in git?

git tag -l --format='%(contents)'


git for-each-ref refs/tags/ --format='%(contents)'

will output full annotation message for every tag (including signature if its signed).

  • %(contents:subject) will output only first line
  • %(contents:body) will output annotation without first line and signature (useful text only)
  • %(contents:signature) will output only PGP-signature

See more in man git-for-each-ref “Field names” section.

Where to put a textfile I want to use in eclipse?

If this is a simple project, you should be able to drag the txt file right into the project folder. Specifically, the "project folder" would be the highest level folder. I tried to do this (for a homework project that I'm doing) by putting the txt file in the src folder, but that didn't work. But finally I figured out to put it in the project file.

A good tutorial for this is I used this as an intro to i/o and it helped.

React eslint error missing in props validation

I know this answer is ridiculous, but consider just disabling this rule until the bugs are worked out or you've upgraded your tooling:

/* eslint-disable react/prop-types */ // TODO: upgrade to latest eslint tooling

Or disable project-wide in your eslintrc:

"rules": {
  "react/prop-types": "off"

How to count how many values per level in a given factor?

Using plyr package:



It will return you a frequency of each value.

Setting PHP tmp dir - PHP upload not working

My problem was selinux...

Go sestatus

If Current mode: enforcing

Then chcon -R -t httpd_sys_rw_content_t /var/www/html

Getting the size of an array in an object

Javascript arrays have a length property. Use it like this:


SELECT list is not in GROUP BY clause and contains nonaggregated column

As @Brian Riley already said you should either remove 1 column in your select

select countrylanguage.language ,sum(country.population*countrylanguage.percentage/100)
from countrylanguage
join country on countrylanguage.countrycode = country.code
group by countrylanguage.language
order by sum(country.population*countrylanguage.percentage) desc ;

or add it to your grouping

select countrylanguage.language, country.code, sum(country.population*countrylanguage.percentage/100)
from countrylanguage
join country on countrylanguage.countrycode = country.code
group by countrylanguage.language, country.code
order by sum(country.population*countrylanguage.percentage) desc ;

Default Xmxsize in Java 8 (max heap size)

On my Ubuntu VM, with 1048 MB total RAM, java -XX:+PrintFlagsFinal -version | grep HeapSize printed : uintx MaxHeapSize := 266338304, which is approx 266MB and is 1/4th of my total RAM.

Oracle timestamp data type

Quite simply the number is the precision of the timestamp, the fraction of a second held in the column:

SQL> create table t23
  2  (ts0 timestamp(0)
  3   , ts3 timestamp(3)
  4  , ts6 timestamp(6)
  5  )
  6  /

Table created.

SQL> insert into t23 values (systimestamp, systimestamp, systimestamp)
  2  /

1 row created.

SQL> select * from t23
  2  /

24-JAN-12 05.57.12 AM
24-JAN-12 AM
24-JAN-12 AM


If we don't specify a precision then the timestamp defaults to six places.

SQL> alter table t23 add ts_def timestamp;

Table altered.

SQL> update t23      
  2  set ts_def = systimestamp
  3  /

1 row updated.

SQL> select * from t23
  2  /

24-JAN-12 05.57.12 AM
24-JAN-12 AM
24-JAN-12 AM
24-JAN-12 AM


Note that I'm running on Linux so my TIMESTAMP column actually gives me precision to six places i.e. microseconds. This would also be the case on most (all?) flavours of Unix. On Windows the limit is three places i.e. milliseconds. (Is this still true of the most modern flavours of Windows - citation needed).

As might be expected, the documentation covers this. Find out more.

"when you create timestamp(9) this gives you nanos right"

Only if the OS supports it. As you can see, my OEL appliance does not:

SQL> alter table t23 add ts_nano timestamp(9)
  2  /

Table altered.

SQL> update t23 set ts_nano = systimestamp(9)
  2  /

1 row updated.

SQL> select * from t23
  2  /

24-JAN-12 05.57.12 AM
24-JAN-12 AM
24-JAN-12 AM
24-JAN-12 AM
24-JAN-12 AM


(Those trailing zeroes could be a coincidence but they aren't.)

How do I insert a drop-down menu for a simple Windows Forms app in Visual Studio 2008?

You can use a ComboBox with its ComboBoxStyle (appears as DropDownStyle in later versions) set to DropDownList. See:

Is there a "between" function in C#?

There is no built in construct in C#/.NET, but you can easily add your own extension method for this:

public static class ExtensionsForInt32
    public static bool IsBetween (this int val, int low, int high)
           return val > low && val < high;

Which can be used like:

if (5.IsBetween (0, 10)) { /* Do something */ }

How to set data attributes in HTML elements

If you're using jQuery, use .data():'myval', 20);

You can store arbitrary data with .data(), but you're restricted to just strings when using .attr().

CharSequence VS String in Java?

I believe it is best to use CharSequence. The reason is that String implements CharSequence, therefore you can pass a String into a CharSequence, HOWEVER you cannot pass a CharSequence into a String, as CharSequence doesn't not implement String. ALSO, in Android the EditText.getText() method returns an Editable, which also implements CharSequence and can be passed easily into one, while not easily into a String. CharSequence handles all!

How to change the status bar background color and text color on iOS 7?

For bar color: You provide a custom background image for the bar.

For text color: Use the information in About Text Handling in iOS

Remove columns from DataTable in C#

To remove all columns after the one you want, below code should work. It will remove at index 10 (remember Columns are 0 based), until the Column count is 10 or less.

DataTable dt;
int desiredSize = 10;

while (dt.Columns.Count > desiredSize)

Error "can't use subversion command line client : svn" when opening android project checked out from svn

This is annoying, I wish IntelliJ would handle this better than a startup nag..

If you are using TortoiseSVN 1.8+ on Windows, do this:

  1. Run the the TortoiseSVN Installer. (It may still be in your Downloads folder)
  2. Select the option to Modify.
  3. Install Command line client tools on to the local harddrive.
  4. Add C:\Program Files\TortoiseSVN\bin to your Path environment variable.
  5. Restart IntelliJ.

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

In my legacy app Array.from of prototype js was conflicting with angular's Array.from that was causing this problem. I resolved it by saving angular's Array.from version and reassigning it after prototype load.

How to do 3 table JOIN in UPDATE query?

An alternative General Plan, which I'm only adding as an independent Answer because the blasted "comment on an answer" won't take newlines without posting the entire edit, even though it isn't finished yet.

UPDATE table A
JOIN table B ON {join fields}
JOIN table C ON {join fields}
JOIN {as many tables as you need}
SET A.column = {expression}


UPDATE person P
JOIN address A ON P.home_address_id =
JOIN city C ON A.city_id =
SET P.home_zip = C.zipcode;

Multi-key dictionary in c#?

I think you would need a Tuple2 like class. Be sure that it's GetHashCode() and Equals() is based upon the two contained elements.

See Tuples in C#

Matplotlib connect scatterplot points with line - Python

For red lines an points

plt.plot(dates, values, '.r-') 

or for x markers and blue lines

plt.plot(dates, values, 'xb-')

Convert LocalDate to LocalDateTime or java.sql.Timestamp


To convert JodaTime's org.joda.time.LocalDate to java.sql.Timestamp, just do

Timestamp timestamp = new Timestamp(localDate.toDateTimeAtStartOfDay().getMillis());

To convert JodaTime's org.joda.time.LocalDateTime to java.sql.Timestamp, just do

Timestamp timestamp = new Timestamp(localDateTime.toDateTime().getMillis());


To convert Java8's java.time.LocalDate to java.sql.Timestamp, just do

Timestamp timestamp = Timestamp.valueOf(localDate.atStartOfDay());

To convert Java8's java.time.LocalDateTime to java.sql.Timestamp, just do

Timestamp timestamp = Timestamp.valueOf(localDateTime);

How can I capture the result of var_dump to a string?


var_dump and print_r functions can only output directly to browser. So the output of these functions can only retrieved by using output control functions of php. Below method may be useful to save the output.

function assignVarDumpValueToString($object) {
    $result = ob_get_clean();
    return $result;

ob_get_clean() can only clear last data entered to internal buffer. So ob_get_contents method will be useful if you have multiple entries.

From the same source as above:

function varDumpToErrorLog( $var=null ){
    ob_start();                    // start reading the internal buffer
    var_dump( $var);          
    $grabbed_information = ob_get_contents(); // assigning the internal buffer contents to variable
    ob_end_clean();                // clearing the internal buffer.
    error_log( $grabbed_information);        // saving the information to error_log

"You have mail" message in terminal, os X

As inspiredlife explained, you can figure out whats happening using mail command.

If you don't want to delete bunch of unrelated / auto-generated messages one by one (like me), simply run the command below to get rid of all messages:

echo -n > /var/mail/yourusername

Average of multiple columns

You could simply do:

Select Req_ID, (avg(R1)+avg(R2)+avg(R3)+avg(R4)+avg(R5))/5 as Average
from Request
Group by Req_ID


I'm assuming that you may have multiple rows with the same Req_ID and in these cases you want to calculate the average across all columns and rows for those rows with the same Req_ID

SQL: IF clause within WHERE clause

There isn't a good way to do this in SQL. Some approaches I have seen:

1) Use CASE combined with boolean operators:

    OrderNumber = CASE 
        WHEN (IsNumeric(@OrderNumber) = 1)
        THEN CONVERT(INT, @OrderNumber)
        ELSE -9999 -- Some numeric value that just cannot exist in the column
    FirstName LIKE CASE
        WHEN (IsNumeric(@OrderNumber) = 0)
        THEN '%' + @OrderNumber
        ELSE ''

2) Use IF's outside the SELECT

IF (IsNumeric(@OrderNumber)) = 1
    SELECT * FROM Table
    WHERE @OrderNumber = OrderNumber
    SELECT * FROM Table
    WHERE OrderNumber LIKE '%' + @OrderNumber

3) Using a long string, compose your SQL statement conditionally, and then use EXEC

The 3rd approach is hideous, but it's almost the only think that works if you have a number of variable conditions like that.

How to set the default value for radio buttons in AngularJS?

In Angular 2 this is how we can set the default value for radio button:


<label class="form-check-label">
          <input type="radio" class="form-check-input" name="gender" 
          [(ngModel)]="gender" id="optionsRadios1" value="male">

In the Component Class set the value of 'gender' variable equal to the value of radio button:

gender = 'male';

org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/CollegeWebsite]]

You have a version conflict, please verify whether compiled version and JVM of Tomcat version are same. you can do it by examining tomcat startup .bat , looking for JAVA_HOME

Android findViewById() in Custom View

If it's fixed layout you can do like that:

public void onClick(View v) {
   ViewGroup parent = (ViewGroup) IdNumber.this.getParent();
   EditText firstName = (EditText) parent.findViewById(;
   firstName.setText("Some Text");

If you want find the EditText in flexible layout, I will help you later. Hope this help.

How to compare only Date without Time in DateTime types in Linq to SQL with Entity Framework?

For a true comparison, you can use:


How to change the default GCC compiler in Ubuntu?

Now, there is gcc-4.9 available for Ubuntu/precise.

Create a group of compiler alternatives where the distro compiler has a higher priority:

root$ VER=4.6 ; PRIO=60
root$ update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-$VER $PRIO --slave /usr/bin/g++ g++ /usr/bin/g++-$VER
root$ update-alternatives --install /usr/bin/cpp cpp-bin /usr/bin/cpp-$VER $PRIO

root$ VER=4.9 ; PRIO=40
root$ update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-$VER $PRIO --slave /usr/bin/g++ g++ /usr/bin/g++-$VER
root$ update-alternatives --install /usr/bin/cpp cpp-bin /usr/bin/cpp-$VER $PRIO

NOTE: g++ version is changed automatically with a gcc version switch. cpp-bin has to be done separately as there exists a "cpp" master alternative.

List available compiler alternatives:

root$ update-alternatives --list gcc
root$ update-alternatives --list cpp-bin

To select manually version 4.9 of gcc, g++ and cpp, do:

root$ update-alternatives --config gcc
root$ update-alternatives --config cpp-bin

Check compiler versions:

root$ for i in gcc g++ cpp ; do $i --version ; done

Restore distro compiler settings (here: back to v4.6):

root$ update-alternatives --auto gcc
root$ update-alternatives --auto cpp-bin

How to copy directories with spaces in the name

robocopy "C:\Users\Angie\My Documents" "C:\test-backup\My Documents" /B /E /R:0 /CREATE /NP /TEE /XJ /LOG+:"CompleteBackupLog.txt"
robocopy "C:\Users\Angie\My Music" "C:\test-backup\My Music" /B /E /R:0 /CREATE /NP /TEE /XJ /LOG+:"CompleteBackupLog.txt"
robocopy "C:\Users\Angie\My Pictures" "C:\test-backup\My Pictures" /B /E /R:0 /CREATE /NP /TEE /XJ /LOG+:"CompleteBackupLog.txt"

How to clear the cache of nginx?

find /etc/nginx/cache_folder -type d -exec rm -rvf {} \;
mkdir /etc/nginx/cache_folder
service nginx restart

Be careful to properly specify the correct path.

.NET DateTime to SqlDateTime Conversion

var sqlCommand = new SqlCommand("SELECT * FROM mytable WHERE start_time >= @StartTime");
sqlCommand.Parameters.Add("@StartTime", SqlDbType.DateTime);
sqlCommand.Parameters("@StartTime").Value = MyDateObj;

Save child objects automatically using JPA Hibernate

Use org.hibernate.annotations for doing Cascade , if the hibernate and JPA are used together , its somehow complaining on saving the child objects.

Convert pandas timezone-aware DateTimeIndex to naive timestamp, but in certain timezone

Building on D.A.'s suggestion that "the only way to do what you want is to modify the underlying data" and using numpy to modify the underlying data...

This works for me, and is pretty fast:

def tz_to_naive(datetime_index):
    """Converts a tz-aware DatetimeIndex into a tz-naive DatetimeIndex,
    effectively baking the timezone into the internal representation.

    datetime_index : pandas.DatetimeIndex, tz-aware

    pandas.DatetimeIndex, tz-naive
    # Calculate timezone offset relative to UTC
    timestamp = datetime_index[0]
    tz_offset = (timestamp.replace(tzinfo=None) - 
    tz_offset_td64 = np.timedelta64(tz_offset)

    # Now convert to naive DatetimeIndex
    return pd.DatetimeIndex(datetime_index.values + tz_offset_td64)

How to create a custom navigation drawer in android

Android Navigation Drawer using Activity I just followed the example :

You just need few Customization:

public class MainActivity extends AppCompatActivity  {

public static final String AVATAR_URL = "";

private DrawerLayout drawerLayout;
private View content;
private Toolbar toolbar;
private NavigationView navigationView;
private ActionBarDrawerToggle drawerToggle;

protected void onCreate(Bundle savedInstanceState) {
    toolbar = (Toolbar) findViewById(;
    drawerLayout = (DrawerLayout) findViewById(;

    content = findViewById(;
    drawerToggle = setupDrawerToggle();
    final ImageView avatar = (ImageView) navigationView.getHeaderView(0).findViewById(;
    Picasso.with(this).load(AVATAR_URL).transform(new CircleTransform()).into(avatar);


private void initToolbar() {
    final Toolbar toolbar = (Toolbar) findViewById(;
    final ActionBar actionBar = getSupportActionBar();

    if (actionBar != null) {
private ActionBarDrawerToggle setupDrawerToggle() {
    return new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.drawer_open,  R.string.drawer_close);

protected void onPostCreate(Bundle savedInstanceState) {
    // Sync the toggle state after onRestoreInstanceState has occurred.

public void onConfigurationChanged(Configuration newConfig) {
    // Pass any configuration change to the drawer toggles
 private void setupDrawerLayout() {

    drawerLayout = (DrawerLayout) findViewById(;
    navigationView = (NavigationView) findViewById(;

    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {

        public boolean onNavigationItemSelected(MenuItem menuItem) {

            int id = menuItem.getItemId();

          switch (id) {
                    Intent i = new Intent(getApplicationContext(), MainActivity.class);
                    Intent j = new Intent(getApplicationContext(), SecondActivity.class);


        return true;

} Here is the xml Layout




            app:layout_scrollFlags="scroll|enterAlways|snap" />




Add drawer.xml in menu

<menu xmlns:android="">






To open and close drawer add this values in string.xml

<string name="drawer_open">Open</string>
<string name="drawer_close">Close</string>


enter code here


    android:text="[email protected]"

sub and gsub function?

That won't work if the string contains more than one match... try this:

echo "/x/y/z/x" | awk '{ gsub("/", "_") ; system( "echo "  $0) }'

or better (if the echo isn't a placeholder for something else):

echo "/x/y/z/x" | awk '{ gsub("/", "_") ; print $0 }'

In your case you want to make a copy of the value before changing it:

echo "/x/y/z/x" | awk '{ c=$0; gsub("/", "_", c) ; system( "echo " $0 " " c )}'

initializing strings as null vs. empty string

Empty-ness and "NULL-ness" are two different concepts. As others mentioned the former can be achieved via std::string::empty(), the latter can be achieved with boost::optional<std::string>, e.g.:

boost::optional<string> myStr;
if (myStr) { // myStr != NULL
    // ...

.substring error: "is not a function"

You can use substr

for example:

new Date().getFullYear().toString().substr(-2)

How to represent a fix number of repeats in regular expression?

^\w{14}$ in Perl and any Perl-style regex.

If you want to learn more about regular expressions - or just need a handy reference - the Wikipedia Entry on Regular Expressions is actually pretty good.

Padding or margin value in pixels as integer using jQuery

Not to necro but I made this which can determine pixels based on a variety of values:

  pixels: function (property, base) {
    var value = $(this).css(property);
    var original = value;
    var outer = property.indexOf('left') != -1 || property.indexOf('right') != -1 
      ? $(this).parent().outerWidth()
      : $(this).parent().outerHeight();

    // EM Conversion Factor
    base = base || 16;

    if (value == 'auto' || value == 'inherit') 
        return outer || 0;

    value = value.replace('rem', '');
    value = value.replace('em', '');

    if (value !== original) {
       value = parseFloat(value);
       return value ? base * value : 0;

    value = value.replace('pt', '');

    if (value !== original) {
       value = parseFloat(value);
       return value ? value * 1.333333 : 0; // 1pt = 1.333px

    value = value.replace('%', '');

    if (value !== original) {
      value = parseFloat(value);
      return value ? (outer * value / 100) : 0;

    value = value.replace('px', '');
    return parseFloat(value) || 0;

This way, we take into account for sizing, and auto / inherit.

No line-break after a hyphen

IE8/9 render the non-breaking hyphen mentioned in CanSpice's answer longer than a typical hyphen. It is the length of an en-dash instead of a typical hyphen. This display difference was a deal breaker for me.

As I could not use the CSS answer specified by Deb I instead opted to use no break tags.


In addition I found a specific scenario that caused IE8/9 to break on a hyphen.

  • A string contains words separated by non-breaking spaces - &nbsp;
  • Width is limited
  • Contains a dash

IE renders it like this.

Example of hyphen breaking in IE8/9

The following code reproduces the problem pictured above. I had to use a meta tag to force rendering to IE9 as IE10 has fixed the issue. No fiddle because it does not support meta tags.

<!DOCTYPE html>
<html lang="en">
        <meta http-equiv="X-UA-Compatible" content="IE=9" />
        <meta charset="utf-8"/>
            body { padding: 20px; }
            div { width: 300px; border: 1px solid gray; }

How to check version of a CocoaPods framework


Cocoapods version

CocoaPods program that is built with Ruby and it will be installable with the default Ruby available on macOS.

pod --version //1.8.0.beta.2
gem which cocoapods //Library/Ruby/Gems/2.3.0/gems/cocoapods-1.8.0.beta.2/lib/cocoapods.rb

//install or update
sudo gem install cocoapods

A pod version

Version of pods that is specified in Podfile


It is located in the same folder as Podfile. Here you can find a version of a pod which is used

Search for pods

If you are interested in all available version of specific pod you can use

pod search <pod_name>
pod trunk info <pod_name>

Set a pod version in Podfile

//specific version
pod '<framework_name>', "<semantic_versioning>"
// for example
pod 'MyFramework', "1.0"

remove table row with specific id

ID attributes cannot start with a number and they should be unique. In any case, you can use :eq() to select a specific row using a 0-based integer:

// Remove the third row
$("#test tr:eq(2)").remove();

Alternatively, rewrite your HTML so that it's valid:

<table id="test">
 <tr id=test1><td>bla</td></tr>
 <tr id=test2><td>bla</td></tr>
 <tr id=test3><td>bla</td></tr>
 <tr id=test4><td>bla</td></tr>

And remove it referencing just the id:


How do I print a list of "Build Settings" in Xcode project?

Although @dunedin15's fantastic answer has served me well on a number of occasions, it can give inaccurate results for some edge-cases, such as when debugging build settings of a static lib for an Archive build.

As an alternative, a Run Script Build Phase can be easily added to any target to “Log Build Settings” when it's built:

Target's Build Phases section w/ added Log Build Settings script phase

To add, (with the target in question selected) under the Build Phases tab-section click the little ? button a dozen-or-so pixels up-left-ward from the Target Dependencies section, and set the shell to /bin/bash and the command to export.  You'll also probably want to drag the phase upwards so that it happens just after Target Dependencies and before Copy Headers or Compile Sources.  Renaming the phase from “Run Script” to “Log Build Settings” isn't a bad idea.

The result is this incredibly helpful listing of current environment variables used for building:

Build Log output w/ export command's results

Error: Registry key 'Software\JavaSoft\Java Runtime Environment'\CurrentVersion'?

I ran into this issue after updating the Java JDK, but had not yet restarted my command prompt. After restarting the command prompt, everything worked fine. Presumably, because the PATH variable need to be reset after the JDK update.

Importing Excel files into R, xlsx or xls

This new package looks nice It doesn't require rJava and is using 'Rcpp' for speed.

How do I show a "Loading . . . please wait" message in Winforms for a long loading form?

You want to look into 'Splash' Screens.

Display another 'Splash' form and wait until the processing is done.

Here is an example on how to do it.

mysqldump with create database line

Here is how to do dump the database (with just the schema):

mysqldump -u root -p"passwd" --no-data --add-drop-database --databases my_db_name | sed 's#/[*]!40000 DROP DATABASE IF EXISTS my_db_name;#' >my_db_name.sql

If you also want the data, remove the --no-data option.

How / can I display a console window in Intellij IDEA?

UPDATE: Console/Terminal feature was implemented in IDEA 13, PyCharm 3, RubyMine 6, WebStorm/PhpStorm 7.

There is a related feature request, please vote. Setting up an external tool to run a terminal can be used as a workaround.

How to list all available Kafka brokers in a cluster?

If you are using new version of Kafka e.g. 5.3.3, you can use

kafka-broker-api-versions  --bootstrap-server BROKER | grep 9092

You just need to pass one of the brokers

How to set a reminder in Android?

Android complete source code for adding events and reminders with start and end time format.

/** Adds Events and Reminders in Calendar. */
private void addReminderInCalendar() {
    Calendar cal = Calendar.getInstance();
    Uri EVENTS_URI = Uri.parse(getCalendarUriBase(true) + "events");
    ContentResolver cr = getContentResolver();
    TimeZone timeZone = TimeZone.getDefault();

    /** Inserting an event in calendar. */
    ContentValues values = new ContentValues();
    values.put(CalendarContract.Events.CALENDAR_ID, 1);
    values.put(CalendarContract.Events.TITLE, "Sanjeev Reminder 01");
    values.put(CalendarContract.Events.DESCRIPTION, "A test Reminder.");
    values.put(CalendarContract.Events.ALL_DAY, 0);
    // event starts at 11 minutes from now
    values.put(CalendarContract.Events.DTSTART, cal.getTimeInMillis() + 11 * 60 * 1000);
    // ends 60 minutes from now
    values.put(CalendarContract.Events.DTEND, cal.getTimeInMillis() + 60 * 60 * 1000);
    values.put(CalendarContract.Events.EVENT_TIMEZONE, timeZone.getID());
    values.put(CalendarContract.Events.HAS_ALARM, 1);
    Uri event = cr.insert(EVENTS_URI, values);

    // Display event id
    Toast.makeText(getApplicationContext(), "Event added :: ID :: " + event.getLastPathSegment(), Toast.LENGTH_SHORT).show();

    /** Adding reminder for event added. */
    Uri REMINDERS_URI = Uri.parse(getCalendarUriBase(true) + "reminders");
    values = new ContentValues();
    values.put(CalendarContract.Reminders.EVENT_ID, Long.parseLong(event.getLastPathSegment()));
    values.put(CalendarContract.Reminders.METHOD, Reminders.METHOD_ALERT);
    values.put(CalendarContract.Reminders.MINUTES, 10);
    cr.insert(REMINDERS_URI, values);

/** Returns Calendar Base URI, supports both new and old OS. */
private String getCalendarUriBase(boolean eventUri) {
    Uri calendarURI = null;
    try {
        if (android.os.Build.VERSION.SDK_INT <= 7) {
            calendarURI = (eventUri) ? Uri.parse("content://calendar/") : Uri.parse("content://calendar/calendars");
        } else {
            calendarURI = (eventUri) ? Uri.parse("content://") : Uri
    } catch (Exception e) {
    return calendarURI.toString();

Add permission to your Manifest file.

<uses-permission android:name="android.permission.READ_CALENDAR" />
<uses-permission android:name="android.permission.WRITE_CALENDAR" />

How to call Oracle MD5 hash function?

I would do:

select DBMS_CRYPTO.HASH(rawtohex('foo') ,2) from dual;



Include an SVG (hosted on GitHub) in MarkDown

Just like this worked for me on Github.

![Imgae Caption](ImageAddressOnGitHub.svg)


<img src="ImageAddressOnGitHub.svg">

Fatal error: Namespace declaration statement has to be the very first statement in the script in

UTF-8 Byte Order Mark at the beginning of the document
^THIS for me solved the issue. I opened the inolved file with an HEX editor and removed the BOM at the start of the file.

Batch / Find And Edit Lines in TXT file

ghostdog74's example provided the core of what I needed, since I've never written any vbs before and needed to do that. It's not perfect, but I fleshed out the example into a full script in case anyone finds it useful.


Option Explicit

Const ForAppending = 8
Const TristateFalse = 0 ' the value for ASCII
Const Overwrite = True

Const WindowsFolder = 0
Const SystemFolder = 1
Const TemporaryFolder = 2

Dim FileSystem
Dim Filename, OldText, NewText
Dim OriginalFile, TempFile, Line
Dim TempFilename

If WScript.Arguments.Count = 3 Then
    Filename = WScript.Arguments.Item(0)
    OldText = WScript.Arguments.Item(1)
    NewText = WScript.Arguments.Item(2)
    Wscript.Echo "Usage: ReplaceText.vbs <Filename> <OldText> <NewText>"
End If

Set FileSystem = CreateObject("Scripting.FileSystemObject")
Dim tempFolder: tempFolder = FileSystem.GetSpecialFolder(TemporaryFolder)
TempFilename = FileSystem.GetTempName

If FileSystem.FileExists(TempFilename) Then
    FileSystem.DeleteFile TempFilename
End If

Set TempFile = FileSystem.CreateTextFile(TempFilename, Overwrite, TristateFalse)
Set OriginalFile = FileSystem.OpenTextFile(Filename)

Do Until OriginalFile.AtEndOfStream
    Line = OriginalFile.ReadLine

    If InStr(Line, OldText) > 0 Then
        Line = Replace(Line, OldText, NewText)
    End If 



FileSystem.DeleteFile Filename
FileSystem.MoveFile TempFilename, Filename


In JavaScript, why is "0" equal to false, but when tested by 'if' it is not false by itself?

In JS "==" sign does not check the type of variable. Therefore, "0" = 0 = false (in JS 0 = false) and will return true in this case, but if you use "===" the result will be false.

When you use "if", it will be "false" in the following case:

[0, false, '', null, undefined, NaN] // null = undefined, 0 = false


if("0") = if( ("0" !== 0) && ("0" !== false) && ("0" !== "") && ("0" !== null) && ("0" !== undefined) && ("0" !== NaN) )
        = if(true && true && true && true && true && true)
        = if(true)

How can I access a hover state in reactjs?

I know the accepted answer is great but for anyone who is looking for a hover like feel you can use setTimeout on mouseover and save the handle in a map (of let's say list ids to setTimeout Handle). On mouseover clear the handle from setTimeout and delete it from the map

onMouseOver={() => this.onMouseOver(someId)}
onMouseOut={() => this.onMouseOut(someId)

And implement the map as follows:

onMouseOver(listId: string) {
    ... // whatever

  const handle = setTimeout(() => {
  }, 1000); // Replace 1000ms with any time you feel is good enough for your hover action
  this.hoverHandleMap[listId] = handle;

onMouseOut(listId: string) {
    ... // whatever

  const handle = this.hoverHandleMap[listId];
  delete this.hoverHandleMap[listId];

And the map is like so,

hoverHandleMap: { [listId: string]: NodeJS.Timeout } = {};

I prefer onMouseOver and onMouseOut because it also applies to all the children in the HTMLElement. If this is not required you may use onMouseEnter and onMouseLeave respectively.

How to add System.Windows.Interactivity to project?

With Blend for Visual Studio, which is included in Visual Studio starting with version 2013, you can find the DLL in the following folder:

C:\Program Files (x86)\Microsoft SDKs\Expression\Blend\.NETFramework\v4.5\Libraries

You will have to add the reference to the System.Windows.Interactivity.dll yourself though, unless you use Blend for Visual Studio with an existing project to add functionality that makes use of the Interactivity namespace. In that case, Blend will add the reference automatically.

How to make the window full screen with Javascript (stretching all over the screen)

A Q&D way to go full screen, if you are in a "kiosk" situation, is to feed an F11 to the browser window after it's up and running. This is not pretty starting up and the user might be able to poke a touch screen at the top and get a semi-full-screen view, but feeding the F11 might do in a pinch or just to get started on a project.

Send password when using scp to copy files from one server to another

Here is how I resolved it.

It is not the most secure way however it solved my problem as security was not an issue on internal servers.

Create a new file say password.txt and store the password for the server where the file will be pasted. Save this to a location on the host server.

scp -W location/password.txt copy_file_location paste_file_location


'too many values to unpack', iterating over a dict. key=>string, value=>list

For Python 3.x iteritems has been removed. Use items instead.

for field, possible_values in fields.items():
    print(field, possible_values)

Looping through the content of a file in Bash

This is no better than other answers, but is one more way to get the job done in a file without spaces (see comments). I find that I often need one-liners to dig through lists in text files without the extra step of using separate script files.

for word in $(cat peptides.txt); do echo $word; done

This format allows me to put it all in one command-line. Change the "echo $word" portion to whatever you want and you can issue multiple commands separated by semicolons. The following example uses the file's contents as arguments into two other scripts you may have written.

for word in $(cat peptides.txt); do $word; $word; done

Or if you intend to use this like a stream editor (learn sed) you can dump the output to another file as follows.

for word in $(cat peptides.txt); do $word; $word; done > outfile.txt

I've used these as written above because I have used text files where I've created them with one word per line. (See comments) If you have spaces that you don't want splitting your words/lines, it gets a little uglier, but the same command still works as follows:

OLDIFS=$IFS; IFS=$'\n'; for line in $(cat peptides.txt); do $line; $line; done > outfile.txt; IFS=$OLDIFS

This just tells the shell to split on newlines only, not spaces, then returns the environment back to what it was previously. At this point, you may want to consider putting it all into a shell script rather than squeezing it all into a single line, though.

Best of luck!

java.lang.OutOfMemoryError: bitmap size exceeds VM budget - Android

I suggest a convenient way to solve this problem. Just assign the attribute "android:configChanges" value as followed in the Mainfest.xml for your errored activity. like this:

<activity android:name=".main.MainActivity"

the first solution I gave out had really reduced the frequency of OOM error to a low level. But, it did not solve the problem totally. And then I will give out the 2nd solution:

As the OOM detailed, I have used too much runtime memory. So, I reduce the picture size in ~/res/drawable of my project. Such as an overqualified picture which has a resolution of 128X128, could be resized to 64x64 which would also be suitable for my application. And after I did so with a pile of pictures, the OOM error doesn't occur again.

Best Way to do Columns in HTML/CSS

You might also try.

  float: left;_x000D_
.col + .col{_x000D_
  float: left;_x000D_
  margin-left: 20px;_x000D_
/* or */_x000D_
  margin-left: 20px;_x000D_
<div class="row">_x000D_
  <div class="col">column</div>_x000D_
  <div class="col">column</div>_x000D_
  <div class="col">column</div>_x000D_


Bash scripting missing ']'

You're missing a space after "p1":

if [ -s "p1" ];

How to detect the swipe left or Right in Android?

I like the code from @user2999943. But just some minor changes for my own purposes.

public boolean onTouchEvent(MotionEvent event)
      case MotionEvent.ACTION_DOWN:
          x1 = event.getX();                         
      case MotionEvent.ACTION_UP:
          x2 = event.getX();
          float deltaX = x2 - x1;

          if (Math.abs(deltaX) > MIN_DISTANCE)
              // Left to Right swipe action
              if (x2 > x1)
                  Toast.makeText(this, "Left to Right swipe [Next]", Toast.LENGTH_SHORT).show ();                     

              // Right to left swipe action               
                  Toast.makeText(this, "Right to Left swipe [Previous]", Toast.LENGTH_SHORT).show ();                    

              // consider as something else - a screen tap for example
    return super.onTouchEvent(event);       

AngularJS : ng-click not working

For ng-click working properly you need define your controller after angularjs script binding and use it via $scope.

WordPress: get author info from post id

  $field = 'display_name';

Valid values for the $field parameter include:

  • admin_color
  • aim
  • comment_shortcuts
  • description
  • display_name
  • first_name
  • ID
  • jabber
  • last_name
  • nickname
  • plugins_last_view
  • plugins_per_page
  • rich_editing
  • syntax_highlighting
  • user_activation_key
  • user_description
  • user_email
  • user_firstname
  • user_lastname
  • user_level
  • user_login
  • user_nicename
  • user_pass
  • user_registered
  • user_status
  • user_url
  • yim

Can I obtain method parameter name using Java reflection?

To add my 2 cents; parameter info is available in a class file "for debugging" when you use javac -g to compile the source. And it is available to APT but you'll need an annotation so no use to you. (Somebody discussed something similar 4-5 years ago here: )

Overall in-short you can't get it unless you work on Source files directly (similar to what APT does at compile time).

Converting string to title case

Try this:

string myText = "a Simple string";

string asTitleCase =

As has already been pointed out, using TextInfo.ToTitleCase might not give you the exact results you want. If you need more control over the output, you could do something like this:

IEnumerable<char> CharsToTitleCase(string s)
    bool newWord = true;
    foreach(char c in s)
        if(newWord) { yield return Char.ToUpper(c); newWord = false; }
        else yield return Char.ToLower(c);
        if(c==' ') newWord = true;

And then use it like so:

var asTitleCase = new string( CharsToTitleCase(myText).ToArray() );

How to fill color in a cell in VBA?

  1. Use conditional formatting instead of VBA to highlight errors.

  2. Using a VBA loop like the one you posted will take a long time to process

  3. the statement If cell.Value = "#N/A" Then will never work. If you insist on using VBA to highlight errors, try this instead.

    Sub ColorCells()

    Dim Data As Range
    Dim cell As Range
    Set currentsheet = ActiveWorkbook.Sheets("Comparison")
    Set Data = currentsheet.Range("A2:AW1048576")
    For Each cell In Data
    If IsError(cell.Value) Then
       cell.Interior.ColorIndex = 3
    End If
    End Sub
  4. Be prepared for a long wait, since the procedure loops through 51 million cells

  5. There are more efficient ways to achieve what you want to do. Update your question if you have a change of mind.

Is there a minlength validation attribute in HTML5?

I used maxlength and minlength with or without required and it worked for me very well for HTML5.

<input id="passcode" type="password" minlength="8" maxlength="10">


Excel "External table is not in the expected format."

This can occur when the workbook is password-protected. There are some workarounds to remove this protection but most of the examples you'll find online are outdated. Either way, the simple solution is to unprotect the workbook manually, otherwise use something like OpenXML to remove the protection programmatically.

SOAP-ERROR: Parsing WSDL: Couldn't load from <URL>

Try this:

$Wsdl = '';
libxml_disable_entity_loader(false); //adding this worked for me
$Client = new SoapClient($Wsdl);

Comparing two joda DateTime instances

This code (example) :

    Chronology ch1 = GregorianChronology.getInstance();     Chronology ch2 = ISOChronology.getInstance();      DateTime dt = new DateTime("2013-12-31T22:59:21+01:00",ch1);     DateTime dt2 = new DateTime("2013-12-31T22:59:21+01:00",ch2);      System.out.println(dt);     System.out.println(dt2);      boolean b = dt.equals(dt2);      System.out.println(b); 

Will print :

2013-12-31T16:59:21.000-05:00 2013-12-31T16:59:21.000-05:00 false 

You are probably comparing two DateTimes with same date but different Chronology.

Why doesn't Java allow overriding of static methods?

Easy solution: Use singleton instance. It will allow overrides and inheritance.

In my system, I have SingletonsRegistry class, which returns instance for passed Class. If instance is not found, it is created.

Haxe language class:

package rflib.common.utils;
import haxe.ds.ObjectMap;

class SingletonsRegistry
  public static var instances:Map<Class<Dynamic>, Dynamic>;

  static function __init__()
    StaticsInitializer.addCallback(SingletonsRegistry, function()
      instances = null;


  public static function getInstance(cls:Class<Dynamic>, ?args:Array<Dynamic>)
    if (instances == null) {
      instances = untyped new ObjectMap<Dynamic, Dynamic>();      

    if (!instances.exists(cls)) 
      if (args == null) args = [];
      instances.set(cls, Type.createInstance(cls, args));

    return instances.get(cls);

  public static function validate(inst:Dynamic, cls:Class<Dynamic>)
    if (instances == null) return;

    var inst2 = instances[cls];
    if (inst2 != null && inst != inst2) throw "Can\'t create multiple instances of " + Type.getClassName(cls) + " - it's singleton!";


How to decompile a whole Jar file?

You extract it and then use jad against the dir.

intl extension: installing php_intl.dll

You can type this command in terminal: sudo apt-get install php-intl

Define css class in django Forms

Here is another solution for adding class definitions to the widgets after declaring the fields in the class.

def __init__(self, *args, **kwargs):
    super(SampleClass, self).__init__(*args, **kwargs)
    self.fields['name'].widget.attrs['class'] = 'my_class'

How to customize the configuration file of the official PostgreSQL Docker image?

My solution is for colleagues who needs to make changes in config before launching docker-entrypoint-initdb.d

I was needed to change 'shared_preload_libraries' setting so during it's work postgres already has new library preloaded and code in docker-entrypoint-initdb.d can use it.

So I just patched postgresql.conf.sample file in Dockerfile:

RUN echo "shared_preload_libraries='citus,pg_cron'" >> /usr/share/postgresql/postgresql.conf.sample
RUN echo "cron.database_name='newbie'" >> /usr/share/postgresql/postgresql.conf.sample

And with this patch it become possible to add extension in .sql file in docker-entrypoint-initdb.d/:


MySQL Select last 7 days

Since you are using an INNER JOIN you can just put the conditions in the WHERE clause, like this:

    tartikel AS p1 INNER JOIN tartikelpict AS p2 
    ON p1.kArtikel = p2.kArtikel
  DATE(dErstellt) > (NOW() - INTERVAL 7 DAY)
  AND p2.nNr = 1
  p1.kArtikel DESC

Change Placeholder Text using jQuery

simply you can use

$("#yourtextboxid").attr("placeholder", "variable");

where, if variable is string then you can use like above, if it is variable replace it with the name like "variable" with out double quotes.

eg: $("#youtextboxid").attr("placeholder", variable); it will work.

Set UIButton title UILabel font size programmatically

You can use:

button.titleLabel.font = [UIFont systemFontOfSize:14.0];

np.mean() vs np.average() in Python NumPy?

In your invocation, the two functions are the same.

average can compute a weighted average though.

Doc links: mean and average

ORA-00054: resource busy and acquire with NOWAIT specified

When you killed the session, the session hangs around for a while in "KILLED" status while Oracle cleans up after it.

If you absolutely must, you can kill the OS process as well (look up v$process.spid), which would release any locks it was holding on to.

See this for more detailed info.

VBA Print to PDF and Save with Automatic File Name

Hopefully this is self explanatory enough. Use the comments in the code to help understand what is happening. Pass a single cell to this function. The value of that cell will be the base file name. If the cell contains "AwesomeData" then we will try and create a file in the current users desktop called AwesomeData.pdf. If that already exists then try AwesomeData2.pdf and so on. In your code you could just replace the lines filename = Application..... with filename = GetFileName(Range("A1"))

Function GetFileName(rngNamedCell As Range) As String
    Dim strSaveDirectory As String: strSaveDirectory = ""
    Dim strFileName As String: strFileName = ""
    Dim strTestPath As String: strTestPath = ""
    Dim strFileBaseName As String: strFileBaseName = ""
    Dim strFilePath As String: strFilePath = ""
    Dim intFileCounterIndex As Integer: intFileCounterIndex = 1

    ' Get the users desktop directory.
    strSaveDirectory = Environ("USERPROFILE") & "\Desktop\"
    Debug.Print "Saving to: " & strSaveDirectory

    ' Base file name
    strFileBaseName = Trim(rngNamedCell.Value)
    Debug.Print "File Name will contain: " & strFileBaseName

    ' Loop until we find a free file number
        If intFileCounterIndex > 1 Then
            ' Build test path base on current counter exists.
            strTestPath = strSaveDirectory & strFileBaseName & Trim(Str(intFileCounterIndex)) & ".pdf"
            ' Build test path base just on base name to see if it exists.
            strTestPath = strSaveDirectory & strFileBaseName & ".pdf"
        End If

        If (Dir(strTestPath) = "") Then
            ' This file path does not currently exist. Use that.
            strFileName = strTestPath
            ' Increase the counter as we have not found a free file yet.
            intFileCounterIndex = intFileCounterIndex + 1
        End If

    Loop Until strFileName <> ""

    ' Found useable filename
    Debug.Print "Free file name: " & strFileName
    GetFileName = strFileName

End Function

The debug lines will help you figure out what is happening if you need to step through the code. Remove them as you see fit. I went a little crazy with the variables but it was to make this as clear as possible.

In Action

My cell O1 contained the string "FileName" without the quotes. Used this sub to call my function and it saved a file.

Sub Testing()
    Dim filename As String: filename = GetFileName(Range("o1"))

    ActiveWorkbook.Worksheets("Sheet1").Range("A1:N24").ExportAsFixedFormat Type:=xlTypePDF, _
                                              filename:=filename, _
                                              Quality:=xlQualityStandard, _
                                              IncludeDocProperties:=True, _
                                              IgnorePrintAreas:=False, _
End Sub

Where is your code located in reference to everything else? Perhaps you need to make a module if you have not already and move your existing code into there.

CSS to stop text wrapping under image

For those who want some background info, here's a short article explaining why overflow: hidden works. It has to do with the so-called block formatting context. This is part of W3C's spec (ie is not a hack) and is basically the region occupied by an element with a block-type flow.

Every time it is applied, overflow: hidden creates a new block formatting context. But it's not the only property capable of triggering that behaviour. Quoting a presentation by Fiona Chan from Sydney Web Apps Group:

  • float: left / right
  • overflow: hidden / auto / scroll
  • display: table-cell and any table-related values / inline-block
  • position: absolute / fixed

Change first commit of project with Git?

If you want to modify only the first commit, you may try git rebase and amend the commit, which is similar to this post: How to modify a specified commit in git?

And if you want to modify all the commits which contain the raw email, filter-branch is the best choice. There is an example of how to change email address globally on the book Pro Git, and you may find this link useful

Setting POST variable without using form

You can do it using jQuery. Example:

<script src=""></script>

        url : "next.php",
        type: "POST",
        data : "name=Denniss",
        success: function(data)
            //data - response from server

Understanding Spring @Autowired usage

Nothing in the example says that the "classes implementing the same interface". MovieCatalog is a type and CustomerPreferenceDao is another type. Spring can easily tell them apart.

In Spring 2.x, wiring of beans mostly happened via bean IDs or names. This is still supported by Spring 3.x but often, you will have one instance of a bean with a certain type - most services are singletons. Creating names for those is tedious. So Spring started to support "autowire by type".

What the examples show is various ways that you can use to inject beans into fields, methods and constructors.

The XML already contains all the information that Spring needs since you have to specify the fully qualified class name in each bean. You need to be a bit careful with interfaces, though:

This autowiring will fail:

 public void prepare( Interface1 bean1, Interface1 bean2 ) { ... }

Since Java doesn't keep the parameter names in the byte code, Spring can't distinguish between the two beans anymore. The fix is to use @Qualifier:

 public void prepare( @Qualifier("bean1") Interface1 bean1,
     @Qualifier("bean2")  Interface1 bean2 ) { ... }

Can't get Python to import from a different folder

I believe you need to create a file called in the Models directory so that python treats it as a module.

Then you can do:

from Models.user import User

You can include code in the (for instance initialization code that a few different classes need) or leave it blank. But it must be there.

How to get value at a specific index of array In JavaScript?

Just use indexer

var valueAtIndex1 = myValues[1];

How can I break from a try/catch block without throwing an exception in Java

Various ways:

  • return
  • break or continue when in a loop
  • break to label when in a labeled statement (see @aioobe's example)
  • break when in a switch statement.


  • System.exit() ... though that's probably not what you mean.

In my opinion, "break to label" is the most natural (least contorted) way to do this if you just want to get out of a try/catch. But it could be confusing to novice Java programmers who have never encountered that Java construct.

But while labels are obscure, in my opinion wrapping the code in a do ... while (false) so that you can use a break is a worse idea. This will confuse non-novices as well as novices. It is better for novices (and non-novices!) to learn about labeled statements.

By the way, return works in the case where you need to break out of a finally. But you should avoid doing a return in a finally block because the semantics are a bit confusing, and liable to give the reader a headache.

Good beginners tutorial to

A 'fun' way to learn is to play BrowserQuest by mozilla and look at its source code :-)

Free easy way to draw graphs and charts in C++?

Honestly, I was in the same boat as you. I've got a C++ Library that I wanted to connect to a graphing utility. I ended up using Boost Python and matplotlib. It was the best one that I could find.

As a side note: I was also wary of licensing. matplotlib and the boost libraries can be integrated into proprietary applications.

Here's an example of the code that I used:

#include <boost/python.hpp>
#include <pygtk/pygtk.h>
#include <gtkmm.h>

using namespace boost::python;
using namespace std;

// This is called in the idle loop.
bool update(object *axes, object *canvas) {
    static object random_integers = object(handle<>(PyImport_ImportModule("numpy.random"))).attr("random_integers");
    axes->attr("scatter")(random_integers(0,1000,1000), random_integers(0,1000,1000));
    return true;

int main() {
    try {
        // Python startup code
        PyRun_SimpleString("import signal");
        PyRun_SimpleString("signal.signal(signal.SIGINT, signal.SIG_DFL)");

        // Normal Gtk startup code
        Gtk::Main kit(0,0);

        // Get the python Figure and FigureCanvas types.
        object Figure = object(handle<>(PyImport_ImportModule("matplotlib.figure"))).attr("Figure");
        object FigureCanvas = object(handle<>(PyImport_ImportModule("matplotlib.backends.backend_gtkagg"))).attr("FigureCanvasGTKAgg");

        // Instantiate a canvas
        object figure = Figure();
        object canvas = FigureCanvas(figure);
        object axes = figure.attr("add_subplot")(111);

        // Create our window.
        Gtk::Window window;
        window.set_title("Engineering Sample");
        window.set_default_size(1000, 600);

        // Grab the Gtk::DrawingArea from the canvas.
        Gtk::DrawingArea *plot = Glib::wrap(GTK_DRAWING_AREA(pygobject_get(canvas.ptr())));

        // Add the plot to the window.

        // On the idle loop, we'll call update(axes, canvas).
        Glib::signal_idle().connect(sigc::bind(&update, &axes, &canvas));

        // And start the Gtk event loop.

    } catch( error_already_set ) {

How to fix Broken pipe?

The above answers illustrate the reason for this Broken pipe: the other end closed the connection. I would like to share experience what happened when I encountered it:

  1. in a client's request, the Content-Type header is mistakenly set larger than request body actually is (in fact there was no body at all)
  2. the bottom service in tomcat socket was waiting for that sized body data (http is on TCP which ensures delivery by encapsulating and ...)
  3. when 60 seconds expired, tomcat throws time out exception: Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception null
  4. client receives a response with status code 500 because of the timeout exception.
  5. client close connection (because it receives response).
  6. tomcat throws Broken pipe because client closed it.

Sometimes, tomcat does not throw broken pip exception, because timeout exception close the connection, why such a difference is confusing me too.

What is the difference between parseInt() and Number()?

Its a good idea to stay away from parseInt and use Number and Math.round unless you need hex or octal. Both can use strings. Why stay away from it?

parseInt(0.001, 10)

parseInt(-0.0000000001, 10)

parseInt(0.0000000001, 10)

parseInt(4000000000000000000000, 10)

It completly butchers really large or really small numbers. Oddly enough it works normally if these inputs are a string.

parseInt("-0.0000000001", 10)

parseInt("0.0000000001", 10)

parseInt("4000000000000000000000", 10)

Instead of risking hard to find bugs with this and the other gotchas people mentioned, I would just avoid parseInt unless you need to parse something other than base 10. Number, Math.round, Math.foor, and .toFixed(0) can all do the same things parseInt can be used for without having these types of bugs.

If you really want or need to use parseInt for some of it's other qualities, never use it to convert floats to ints.

Export a list into a CSV or TXT file in R

cat(capture.output(print(my.list), file="test.txt"))

from R: Export and import a list to .txt file is the only thing that worked for me. This outputs the list of lists as it is in the text file

Access Tomcat Manager App from different host

For Tomcat v8.5.4 and above, the file <tomcat>/webapps/manager/META-INF/context.xml has been adjusted:

<Context antiResourceLocking="false" privileged="true" >
    <Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />

Change this file to comment the Valve:

<Context antiResourceLocking="false" privileged="true" >
    <Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />

After that, refresh your browser (not need to restart Tomcat), you can see the manager page.

How to set page content to the middle of screen?

If you want to center the content horizontally and vertically, but don't know in prior how high your page will be, you have to you use JavaScript.


    <div id="content">...</div>


#content {
    max-width: 1000px;
    margin: auto;
    left: 1%;
    right: 1%;
    position: absolute;

JavaScript (using jQuery):

$(function() {
    $(window).on('resize', function resize()  {
        $(window).off('resize', resize);
        setTimeout(function () {
            var content = $('#content');
            var top = (window.innerHeight - content.height()) / 2;
            content.css('top', Math.max(0, top) + 'px');
            $(window).on('resize', resize);
        }, 50);

Centered horizontally and vertically


What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phone

As for "phone numbers" you should really consider the difference between a "subscriber number" and a "dialling number" and the possible formatting options of them.

A subscriber number is generally defined in the national numbering plans. The question itself shows a relation to a national view by mentioning "area code" which a lot of nations don't have. ITU has assembled an overview of the world's numbering plans publishing recommendation E.164 where the national number was found to have a maximum of 12 digits. With international direct distance calling (DDD) defined by a country code of 1 to 3 digits they added that up to 15 digits ... without formatting.

The dialling number is a different thing as there are network elements that can interpret exta values in a phone number. You may think of an answering machine and a number code that sets the call diversion parameters. As it may contain another subscriber number it must be obviously longer than its base value. RFC 4715 has set aside 20 bcd-encoded bytes for "subaddressing".

If you turn to the technical limitation then it gets even more as the subscriber number has a technical limit in the 10 bcd-encoded bytes in the 3GPP standards (like GSM) and ISDN standards (like DSS1). They have a seperate TON/NPI byte for the prefix (type of number / number plan indicator) which E.164 recommends to be written with a "+" but many number plans define it with up to 4 numbers to be dialled.

So if you want to be future proof (and many software systems run unexpectingly for a few decades) you would need to consider 24 digits for a subscriber number and 64 digits for a dialling number as the limit ... without formatting. Adding formatting may add roughly an extra character for every digit. So as a final thought it may not be a good idea to limit the phone number in the database in any way and leave shorter limits to the UX designers.

How to concatenate strings in twig

{{ ['foo', 'bar'|capitalize]|join }}

As you can see this works with filters and functions without needing to use set on a seperate line.

How do I resolve "HTTP Error 500.19 - Internal Server Error" on IIS7.0

I had the same issue, but reason was different.

In my web.config there was a URL rewrite module rule and I haven’t installed URL rewrite module also. After I install url rewrite module this problem solved.

How do I determine file encoding in OS X?

vim -c 'execute "silent !echo " . &fileencoding | q' {filename}

aliased somewhere in my bash configuration as

alias vic="vim -c 'execute \"silent \!echo \" . &fileencoding | q'"

so I just type

vic {filename}

On my vanilla OSX Yosemite, it yields more precise results than "file -I":

$ file -I pdfs/udocument0.pdf
pdfs/udocument0.pdf: application/pdf; charset=binary
$ vic pdfs/udocument0.pdf
$ file -I pdfs/t0.pdf
pdfs/t0.pdf: application/pdf; charset=us-ascii
$ vic pdfs/t0.pdf

How to replace NA values in a table for selected columns

Not sure if this is more concise, but this function will also find and allow replacement of NAs (or any value you like) in selected columns of a data.table:

update.mat <- function(dt, cols, criteria) {
  x <-, arr.ind = TRUE))
  y <- as.matrix(subset(x, x$col %in% which((names(dt) %in% cols), arr.ind = TRUE)))

To apply it:

y[update.mat(y, c("a", "b"),] <- 0

The function creates a matrix of the selected columns and rows (cell coordinates) that meet the input criteria (in this case == TRUE).

JavaScript/jQuery to download file via POST with JSON data

In short, there is no simpler way. You need to make another server request to show PDF file. Al though, there are few alternatives but they are not perfect and won't work on all browsers:

  1. Look at data URI scheme. If binary data is small then you can perhaps use javascript to open window passing data in URI.
  2. Windows/IE only solution would be to have .NET control or FileSystemObject to save the data on local file system and open it from there.

How to parse XML using vba

Often it is easier to parse without VBA, when you don't want to enable macros. This can be done with the replace function. Enter your start and end nodes into cells B1 and C1.

Cell A1: {your XML here}
Cell B1: <X>
Cell C1: </X>
Cell D1: =REPLACE(A1,1,FIND(A2,A1)+LEN(A2)-1,"")
Cell E1: =REPLACE(A4,FIND(A3,A4),LEN(A4)-FIND(A3,A4)+1,"")

And the result line E1 will have your parsed value:

Cell A1: {your XML here}
Cell B1: <X>
Cell C1: </X>
Cell D1: 24.365<X><Y>78.68</Y></PointN>
Cell E1: 24.365

How many socket connections possible?

On Linux you should be looking at using epoll for async I/O. It might also be worth fine-tuning socket-buffers to not waste too much kernel space per connection.

I would guess that you should be able to reach 100k connections on a reasonable machine.

Array formula on Excel for Mac

Found a solution to Excel Mac2016 as having to paste the code into the relevant cell, enter, then go to the end of the formula within the header bar and enter the following:

Enter a formula as an array formula Image + SHIFT + RETURN or CONTROL + SHIFT + RETURN

Filename too long in Git for Windows

Move repository to root of your drive (temporary fix)

You can try to temporarily move the local repository (the entire folder) to the root of your drive or as close to the root as possible.

Since the path is smaller at the root of the drive, it sometimes fixes the issues.

On Windows, I'd move this to C:\ or another drive's root.

How to stick text to the bottom of the page?

This is how I've done it.

#copyright {_x000D_
 float: left;_x000D_
 padding-bottom: 10px;_x000D_
 padding-top: 10px;_x000D_
 text-align: center;_x000D_
 bottom: 0px;_x000D_
 width: 100%;_x000D_
  <div id="copyright">_x000D_
  Copyright 2018 &copy; Steven Clough_x000D_

Change values on matplotlib imshow() graph axis

I would try to avoid changing the xticklabels if possible, otherwise it can get very confusing if you for example overplot your histogram with additional data.

Defining the range of your grid is probably the best and with imshow it can be done by adding the extent keyword. This way the axes gets adjusted automatically. If you want to change the labels i would use set_xticks with perhaps some formatter. Altering the labels directly should be the last resort.

fig, ax = plt.subplots(figsize=(6,6))

ax.imshow(hist,, interpolation='none', extent=[80,120,32,0])
ax.set_aspect(2) # you may also use am.imshow(..., aspect="auto") to restore the aspect ratio

enter image description here

HTML/Javascript: how to access JSON data loaded in a script tag with src set

It would appear this is not possible, or at least not supported.

From the HTML5 specification:

When used to include data blocks (as opposed to scripts), the data must be embedded inline, the format of the data must be given using the type attribute, the src attribute must not be specified, and the contents of the script element must conform to the requirements defined for the format used.

Ruby on Rails. How do I use the Active Record .build method in a :belongs to relationship?

@article = => "MainTitle")

jQuery Set Select Index

You can also init multiple values if your selectbox is a multipl:

$('#selectBox').val(['A', 'B', 'C']);

Best TCP port number range for internal applications

I can't see why you would care. Other than the "don't use ports below 1024" privilege rule, you should be able to use any port because your clients should be configurable to talk to any IP address and port!

If they're not, then they haven't been done very well. Go back and do them properly :-)

In other words, run the server at IP address X and port Y then configure clients with that information. Then, if you find you must run a different server on X that conflicts with your Y, just re-configure your server and clients to use a new port. This is true whether your clients are code, or people typing URLs into a browser.

I, like you, wouldn't try to get numbers assigned by IANA since that's supposed to be for services so common that many, many environments will use them (think SSH or FTP or TELNET).

Your network is your network and, if you want your servers on port 1234 (or even the TELNET or FTP ports for that matter), that's your business. Case in point, in our mainframe development area, port 23 is used for the 3270 terminal server which is a vastly different beast to telnet. If you want to telnet to the UNIX side of the mainframe, you use port 1023. That's sometimes annoying if you use telnet clients without specifying port 1023 since it hooks you up to a server that knows nothing of the telnet protocol - we have to break out of the telnet client and do it properly:

telnet 1023

If you really can't make the client side configurable, pick one in the second range, like 48042, and just use it, declaring that any other software on those boxes (including any added in the future) has to keep out of your way.

Do you need to dispose of objects and set them to null?

If the object implements IDisposable, then yes, you should dispose it. The object could be hanging on to native resources (file handles, OS objects) that might not be freed immediately otherwise. This can lead to resource starvation, file-locking issues, and other subtle bugs that could otherwise be avoided.

See also Implementing a Dispose Method on MSDN.

Combining C++ and C - how does #ifdef __cplusplus work?

A couple of gotchas that are colloraries to Andrew Shelansky's excellent answer and to disagree a little with doesn't really change the way that the compiler reads the code

Because your function prototypes are compiled as C, you can't have overloading of the same function names with different parameters - that's one of the key features of the name mangling of the compiler. It is described as a linkage issue but that is not quite true - you will get errors from both the compiler and the linker.

The compiler errors will be if you try to use C++ features of prototype declaration such as overloading.

The linker errors will occur later because your function will appear to not be found, if you do not have the extern "C" wrapper around declarations and the header is included in a mixture of C and C++ source.

One reason to discourage people from using the compile C as C++ setting is because this means their source code is no longer portable. That setting is a project setting and so if a .c file is dropped into another project, it will not be compiled as c++. I would rather people take the time to rename file suffixes to .cpp.

How to set shape's opacity?

Use this one, I've written this to my app,

<?xml version="1.0" encoding="utf-8"?>
<!--  res/drawable/rounded_edittext.xml -->
<shape xmlns:android=""
    android:shape="rectangle" android:padding="10dp">
    <solid android:color="#882C383E"/>

Changing upload_max_filesize on PHP

This solution can be applied only if the issue is on a WordPress installation!

If you don't have FTP access or too lazy to edit files,

You can use Increase Maximum Upload File Size plugin to increase the maximum upload file size.

What is the difference between instanceof and Class.isAssignableFrom(...)?

How about some examples to show it in action...

public void isInstanceOf() {
    Exception anEx1 = new Exception("ex");
    Exception anEx2 = new RuntimeException("ex");
    RuntimeException anEx3 = new RuntimeException("ex");

    //Base case, handles inheritance
    Assert.assertTrue(anEx1 instanceof Exception);
    Assert.assertTrue(anEx2 instanceof Exception);
    Assert.assertTrue(anEx3 instanceof Exception);

    //Other cases
    Assert.assertFalse(anEx1 instanceof RuntimeException);
    Assert.assertTrue(anEx2 instanceof RuntimeException);
    Assert.assertTrue(anEx3 instanceof RuntimeException);

public void isAssignableFrom() {
    Exception anEx1 = new Exception("ex");
    Exception anEx2 = new RuntimeException("ex");
    RuntimeException anEx3 = new RuntimeException("ex");

    //Correct usage = The base class goes first

    //Incorrect usage = Method parameter is used in the wrong order

How to know if .keyup() is a character key (jQuery)

This helped for me:

$("#input").keyup(function(event) {
        //use keyup instead keypress because:
        //- keypress will not work on backspace and delete
        //- keypress is called before the character is added to the textfield (at least in google chrome) 
        var searchText = $.trim($("#input").val());

        var c= String.fromCharCode(event.keyCode);
        var isWordCharacter = c.match(/\w/);
        var isBackspaceOrDelete = (event.keyCode == 8 || event.keyCode == 46);

        // trigger only on word characters, backspace or delete and an entry size of at least 3 characters
        if((isWordCharacter || isBackspaceOrDelete) && searchText.length > 2)
        { ...

ASP.NET MVC - Find Absolute Path to the App_Data folder from Controller


string path = HttpContext.Current.Server.MapPath("~/App_Data/somedata.xml");


string path = Server.MapPath("~/App_Data/somedata.xml");

MSDN Reference:

HttpServerUtility.MapPath Method

Can the Twitter Bootstrap Carousel plugin fade in and out on slide transition

Yes. Although I use the following code.

    opacity: 1;

        -moz-transition: opacity ease-in-out .7s;
        -o-transition: opacity ease-in-out .7s;
        -webkit-transition: opacity ease-in-out .7s;
        transition: opacity ease-in-out .7s;
        left: 0 !important;
        opacity: 0;
        width: 100%;
        display:block !important;

            opacity: 1;
            -moz-transition: opacity ease-in-out .7s;
            -o-transition: opacity ease-in-out .7s;
            -webkit-transition: opacity ease-in-out .7s;
            transition: opacity ease-in-out .7s;

Then change the class on the carousel from "carousel slide" to "carousel fade". This works in safari, chrome, firefox, and IE 10. It will correctly downgrade in IE 9, however, the nice face effect doesn't happen.

Edit: Since this answer has gotten so popular I've added the following which rewritten as pure CSS instead of the above which was LESS:

.carousel.fade {
  opacity: 1;
.carousel.fade .item {
  -moz-transition: opacity ease-in-out .7s;
  -o-transition: opacity ease-in-out .7s;
  -webkit-transition: opacity ease-in-out .7s;
  transition: opacity ease-in-out .7s;
  left: 0 !important;
  opacity: 0;
  width: 100%;
  display:block !important;
.carousel.fade .item:first-child {
.carousel.fade {
  opacity: 1;
  -moz-transition: opacity ease-in-out .7s;
  -o-transition: opacity ease-in-out .7s;
  -webkit-transition: opacity ease-in-out .7s;
  transition: opacity ease-in-out .7s;

console.log not working in Angular2 Component (Typescript)

It's not working because console.log() it's not in a "executable area" of the class "App".

A class is a structure composed by attributes and methods.

The only way to have your code executed is to place it inside a method that is going to be executed. For instance: constructor()

console.log('It works here')_x000D_
export class App {_x000D_
 s: string = "Hello2";_x000D_
  constructor() {_x000D_
    console.log(this.s)            _x000D_
  }            _x000D_

Think of class like a plain javascript object.

Would it make sense to expect this to work?

class:  {_x000D_
  s: string,_x000D_

If you still unsure, try the typescript playground where you can see your typescript code generated into plain javascript.

How to add an auto-incrementing primary key to an existing table, in PostgreSQL?

(Updated - Thanks to the people who commented)

Modern Versions of PostgreSQL

Suppose you have a table named test1, to which you want to add an auto-incrementing, primary-key id (surrogate) column. The following command should be sufficient in recent versions of PostgreSQL:


Older Versions of PostgreSQL

In old versions of PostgreSQL (prior to 8.x?) you had to do all the dirty work. The following sequence of commands should do the trick:

  ALTER TABLE test ALTER COLUMN id SET DEFAULT nextval('test_id_seq');
  UPDATE test1 SET id = nextval('test_id_seq');

Again, in recent versions of Postgres this is roughly equivalent to the single command above.

Checking to see if one array's elements are in another array in PHP

You could also use in_array as follows:

$found = null;
$people = array(3,20,2);
$criminals = array( 2, 4, 8, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20);
foreach($people as $num) {
    if (in_array($num,$criminals)) {
        $found[$num] = true;
// array(2) { [20]=> bool(true)   [2]=> bool(true) }

While array_intersect is certainly more convenient to use, it turns out that its not really superior in terms of performance. I created this script too:

$found = null;
$people = array(3,20,2);
$criminals = array( 2, 4, 8, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20);
$fastfind = array_intersect($people,$criminals);
// array(2) { [1]=> int(20)   [2]=> int(2) }

Then, I ran both snippets respectively at: and and checked the performance of each. The interesting thing is that the total CPU time, i.e. user time + system time is the same for PHP5.6 and the memory also is the same. The total CPU time under PHP5.4 is less for in_array than array_intersect, albeit marginally so.

Simple parse JSON from URL on Android and display in listview

HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(url));
HttpResponse response = client.execute(request);
BufferedReader in = new BufferedReader(new InputStreamReader(response
String line = "";

while ((line = in.readLine()) != null) {

    JSONObject jObject = new JSONObject(line);

    if (jObject.has("name")) {

        String temp = jObject.getString("name");



Return multiple values in JavaScript?

You can do this from ECMAScript 6 onwards using arrays and "destructuring assignments". Note that these are not available in older Javascript versions (meaning — neither with ECMAScript 3rd nor 5th editions).

It allows you to assign to 1+ variables simultaneously:

var [x, y] = [1, 2];
x; // 1
y; // 2

// or

[x, y] = (function(){ return [3, 4]; })();
x; // 3
y; // 4

You can also use object destructuring combined with property value shorthand to name the return values in an object and pick out the ones you want:

let {baz, foo} = (function(){ return {foo: 3, bar: 500, baz: 40} })();
baz; // 40
foo; // 3

And by the way, don't be fooled by the fact that ECMAScript allows you to return 1, 2, .... What really happens there is not what might seem. An expression in return statement — 1, 2, 3 — is nothing but a comma operator applied to numeric literals (1 , 2, and 3) sequentially, which eventually evaluates to the value of its last expression — 3. That's why return 1, 2, 3 is functionally identical to nothing more but return 3.

return 1, 2, 3;
// becomes
return 2, 3;
// becomes
return 3;

Can I calculate z-score with R?

if x is a vector with raw scores then scale(x) is a vector with standardized scores.

Or manually: (x-mean(x))/sd(x)