Programs & Examples On #Reloaddata

How to tell when UITableView has completed ReloadData?

Actually this one solved my problem:

-(void) tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {

NSSet *visibleSections = [NSSet setWithArray:[[tableView indexPathsForVisibleRows] valueForKey:@"section"]];
if (visibleSections) {
    // hide the activityIndicator/Loader

Initializing IEnumerable<string> In C#

IEnumerable is just an interface and so can't be instantiated directly.

You need to create a concrete class (like a List)

IEnumerable<string> m_oEnum = new List<string>() { "1", "2", "3" };

you can then pass this to anything expecting an IEnumerable.

grep without showing path/file:line

Just replace -H with -h. Check man grep for more details on options

find . -name '*.bar' -exec grep -hn FOO {} \;

How to add an item to a drop down list in ASP.NET?

Try this, it will insert the list item at index 0;

DropDownList1.Items.Insert(0, new ListItem("Add New", ""));

What is a good game engine that uses Lua?

I can second the previous posters enthusiasm for the Gideros Lua game engine, whilst focusing currently on Mobile (iOS and Android - Windows phone 8 is in the works), desktop support for Mac, PC (possibly Linux) is also planned for the not too distant future.

Google for "Gideros Mobile"

How to prevent background scrolling when Bootstrap 3 modal open on mobile browsers?

Courtesy of JDiApice who synthesized and extended the work of other contributors at iOS 8.x modal scroll issue #14839:

@media only screen and (max-device-width:768px) {

body.modal-open {
    // block scroll for mobile;
    // causes underlying page to jump to top;
    // prevents scrolling on all screens
    overflow: hidden;
    position: fixed;

body.viewport-lg {
    // block scroll for desktop;
    // will not jump to top;
    // will not prevent scroll on mobile
    position: absolute;

body {
    overflow-x: hidden;
    overflow-y: scroll !important;

/* The reason the media specific is on there is 
   on a desktop i was having issues with when the modal would open 
   all content on the page would shift from centered to left. 
   Looked like crap. So this targets up to tablet size devices 
   where you would need to scroll. There is still a slight shift 
   on mobile and tablet but its really not much. */

Unlike the other solutions we tried, it does not scroll the background to the top after the popup modal closes.

Excel SUMIF between dates

You haven't got your SUMIF in the correct order - it needs to be range, criteria, sum range. Try:


How to add row in JTable?


    DefaultTableModel model = (DefaultTableModel) MyJTable.getModel();

    Vector row = new Vector();
    row.add("Enter data to column 1");
    row.add("Enter data to column 2");
    row.add("Enter data to column 3");

get the model with DefaultTableModel modelName = (DefaultTableModel) JTabelName.getModel();

Create a Vector with Vector vectorName = new Vector();

add so many row.add as comumns

add soon just add it with modelName.addRow(Vector name);

The imported project "C:\Microsoft.CSharp.targets" was not found

If you are to encounter the error that says Microsoft.CSharp.Core.targets not found, these are the steps I took to correct mine:

  1. Open any previous working projects folder and navigate to the link showed in the error, that is Projects/(working project name)/packages/Microsoft.Net.Compilers.1.3.2/tools/ and search for Microsoft.CSharp.Core.targets file.

  2. Copy this file and put it in the non-working project tools folder (that is, navigating to the tools folder in the non-working project as shown above)

  3. Now close your project (if it was open) and reopen it.

It should be working now.

Also, to make sure everything is working properly in your now open Visual Studio Project, Go to Tools > NuGetPackage Manager > Manage NuGet Packages For Solution. Here, you might find an error that says, CodeAnalysis.dll is being used by another application.

Again, go to the tools folder, find the specified file and delete it. Come back to Manage NuGet Packages For Solution. You will find a link that will ask you to Reload, click it and everything gets re-installed.

Your project should be working properly now.

Async image loading from url inside a UITableView cell - image changes to wrong image while scrolling

Thank you "Rob"....I had same problem with UICollectionView and your answer help me to solved my problem. Here is my code :

 if ([Dict valueForKey:@"ImageURL"] != [NSNull null])
        cell.coverImageView.image = nil;

        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

            if ([Dict valueForKey:@"ImageURL"] != [NSNull null] )
                dispatch_async(dispatch_get_main_queue(), ^{

                    myCell *updateCell = (id)[collectionView cellForItemAtIndexPath:indexPath];

                    if (updateCell)
                        cell.coverImageView.image = nil;

                        cell.coverImageView.imageURL=[NSURL URLWithString:[Dict valueForKey:@"ImageURL"]];

                        cell.coverImageView.image = nil;


        cell.coverImageView.image=[UIImage imageNamed:@"default_cover.png"];

Compare two columns using pandas

Use lambda expression:

df[df.apply(lambda x: x['col1'] != x['col2'], axis = 1)]

Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed

Here is a Powershell alternative to @UuDdLrLrSs answer.

Get-Service workstation | Restart-Service -Force

object==null or null==object?

This is not of much value in Java (1.5+) except when the type of object is Boolean. In which case, this can still be handy.

if (object = null) will not cause compilation failure in Java 1.5+ if object is Boolean but would throw a NullPointerException at runtime.

HttpUtility does not exist in the current context

After following the answers above , and did

Project -> Properties -> Application -> Target Framework -> select ".Net Framework 4"

It still didn't work until I went to
Project -> Add Reference
And selected System.web. And everything worked link a charm.

How to scale Docker containers in production

Deis automates scaling of Docker containers (among other things).

Deis (pronounced DAY-iss) is an open source PaaS that makes it easy to deploy and manage applications on your own servers. Deis builds upon Docker and CoreOS to provide a lightweight PaaS with a Heroku-inspired workflow.

Here is the developer workflow:

deis create myapp                      # create a new deis app called "myapp"
git push deis master                   # built with a buildpack or dockerfile
deis scale web=16 worker=4             # scale up docker containers

Deis automatically deploys your Docker containers across a CoreOS cluster and configures the Nginx routers to route requests to healthy Docker containers. If a host dies, containers are automatically restarted on another host in seconds. Just browse to the proxy URL or use deis open to hit your app.

Some other useful commands:

deis config:set DATABASE_URL=          # attach to a database w/ an envvar
deis run make test                     # run ephemeral containers for one-off tasks
deis logs                              # get aggregated logs for troubleshooting
deis rollback v23                      # rollback to a prior release

To see this in action, check out the terminal video at You can also learn about Deis concepts or jump right into deploying your own private PaaS.

How do I refresh the page in ASP.NET? (Let it reload itself by code)

There are various method to refresh the page in like...

Java Script

 function reloadPage()

Code Behind


Meta Tag

<meta http-equiv="refresh" content="600"></meta>

Page Redirection

Response.Redirect("~/default.aspx"); // Or whatever your page url

Server is already running in Rails

Remove the file: C:/Sites/folder/Pids/Server.pids

Explanation In UNIX land at least we usually track the process id (pid) in a file like I think this is doing the same thing here. That file was probably left over from a crash.

How to check whether input value is integer or float?


(value % 1) == 0

would work!

Sending SOAP request using Python Requests

It is indeed possible.

Here is an example calling the Weather SOAP Service using plain requests lib:

import requests
#headers = {'content-type': 'application/soap+xml'}
headers = {'content-type': 'text/xml'}
body = """<?xml version="1.0" encoding="UTF-8"?>
         <SOAP-ENV:Envelope xmlns:ns0="" xmlns:ns1="" 
            xmlns:xsi="" xmlns:SOAP-ENV="">

response =,data=body,headers=headers)
print response.content

Some notes:

  • The headers are important. Most SOAP requests will not work without the correct headers. application/soap+xml is probably the more correct header to use (but the weatherservice prefers text/xml
  • This will return the response as a string of xml - you would then need to parse that xml.
  • For simplicity I have included the request as plain text. But best practise would be to store this as a template, then you can load it using jinja2 (for example) - and also pass in variables.

For example:

from jinja2 import Environment, PackageLoader
env = Environment(loader=PackageLoader('myapp', 'templates'))
template = env.get_template('soaprequests/WeatherSericeRequest.xml')
body = template.render()

Some people have mentioned the suds library. Suds is probably the more correct way to be interacting with SOAP, but I often find that it panics a little when you have WDSLs that are badly formed (which, TBH, is more likely than not when you're dealing with an institution that still uses SOAP ;) ).

You can do the above with suds like so:

from suds.client import Client
client = Client(url)
print client ## shows the details of this service

result = client.service.GetWeatherInformation() 
print result 

Note: when using suds, you will almost always end up needing to use the doctor!

Finally, a little bonus for debugging SOAP; TCPdump is your friend. On Mac, you can run TCPdump like so:

sudo tcpdump -As 0 

This can be helpful for inspecting the requests that actually go over the wire.

The above two code snippets are also available as gists:

How to set a value for a span using jQuery

You're looking for the wrong selector id:


should be


How to include the reference of DocumentFormat.OpenXml.dll on Mono2.10?

You need to have DocumentFormat.OpenXML.dll in the same folder as your application - or in the 'bin' path if you are developing an ASP.NET application. However, I'm not certain that the OpenXML SDK is supported on non-Windows operating systems - you may need to look into a third-party solution.

Yes, this answer is right, the only difference is that you copy your .dll into bin folder of the project.

Python Pandas User Warning: Sorting because non-concatenation axis is not aligned


concat and append currently sort the non-concatenation index (e.g. columns if you're adding rows) if the columns don't match. In pandas 0.23 this started generating a warning; pass the parameter sort=True to silence it. In the future the default will change to not sort, so it's best to specify either sort=True or False now, or better yet ensure that your non-concatenation indices match.

The warning is new in pandas 0.23.0:

In a future version of pandas pandas.concat() and DataFrame.append() will no longer sort the non-concatenation axis when it is not already aligned. The current behavior is the same as the previous (sorting), but now a warning is issued when sort is not specified and the non-concatenation axis is not aligned, link.

More information from linked very old github issue, comment by smcinerney :

When concat'ing DataFrames, the column names get alphanumerically sorted if there are any differences between them. If they're identical across DataFrames, they don't get sorted.

This sort is undocumented and unwanted. Certainly the default behavior should be no-sort.

After some time the parameter sort was implemented in pandas.concat and DataFrame.append:

sort : boolean, default None

Sort non-concatenation axis if it is not already aligned when join is 'outer'. The current default of sorting is deprecated and will change to not-sorting in a future version of pandas.

Explicitly pass sort=True to silence the warning and sort. Explicitly pass sort=False to silence the warning and not sort.

This has no effect when join='inner', which already preserves the order of the non-concatenation axis.

So if both DataFrames have the same columns in the same order, there is no warning and no sorting:

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8]}, columns=['a', 'b'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3]}, columns=['a', 'b'])

print (pd.concat([df1, df2]))
   a  b
0  1  0
1  2  8
0  4  7
1  5  3

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8]}, columns=['b', 'a'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3]}, columns=['b', 'a'])

print (pd.concat([df1, df2]))
   b  a
0  0  1
1  8  2
0  7  4
1  3  5

But if the DataFrames have different columns, or the same columns in a different order, pandas returns a warning if no parameter sort is explicitly set (sort=None is the default value):

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8]}, columns=['b', 'a'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3]}, columns=['a', 'b'])

print (pd.concat([df1, df2]))

FutureWarning: Sorting because non-concatenation axis is not aligned.

   a  b
0  1  0
1  2  8
0  4  7
1  5  3

print (pd.concat([df1, df2], sort=True))
   a  b
0  1  0
1  2  8
0  4  7
1  5  3

print (pd.concat([df1, df2], sort=False))
   b  a
0  0  1
1  8  2
0  7  4
1  3  5

If the DataFrames have different columns, but the first columns are aligned - they will be correctly assigned to each other (columns a and b from df1 with a and b from df2 in the example below) because they exist in both. For other columns that exist in one but not both DataFrames, missing values are created.

Lastly, if you pass sort=True, columns are sorted alphanumerically. If sort=False and the second DafaFrame has columns that are not in the first, they are appended to the end with no sorting:

df1 = pd.DataFrame({"a": [1, 2], "b": [0, 8], 'e':[5, 0]}, 
                    columns=['b', 'a','e'])
df2 = pd.DataFrame({"a": [4, 5], "b": [7, 3], 'c':[2, 8], 'd':[7, 0]}, 

print (pd.concat([df1, df2]))

FutureWarning: Sorting because non-concatenation axis is not aligned.

   a  b    c    d    e
0  1  0  NaN  NaN  5.0
1  2  8  NaN  NaN  0.0
0  4  7  2.0  7.0  NaN
1  5  3  8.0  0.0  NaN

print (pd.concat([df1, df2], sort=True))
   a  b    c    d    e
0  1  0  NaN  NaN  5.0
1  2  8  NaN  NaN  0.0
0  4  7  2.0  7.0  NaN
1  5  3  8.0  0.0  NaN

print (pd.concat([df1, df2], sort=False))

   b  a    e    c    d
0  0  1  5.0  NaN  NaN
1  8  2  0.0  NaN  NaN
0  7  4  NaN  2.0  7.0
1  3  5  NaN  8.0  0.0

In your code:

placement_by_video_summary = placement_by_video_summary.drop(placement_by_video_summary_new.index)
                                                       .append(placement_by_video_summary_new, sort=True)

Bootstrap Modal Backdrop Remaining

The best and simple approach is by using the data-dismiss attribute. Basically the data-dismiss attribute will dismiss the modal and you won't see the backdrop remaining.

How to use data-dismiss attribute

All you need to do is adding the following at the place where you want to close your modal:


For example, I have a button and when someone clicks the button it will close the modal.

<button class="btn btn-info float-right" onclick="foo()" data-dismiss="modal">Save changes</button>

You can also handle the JavaScript function on onClick and it will close the modal and also run the JavaScript function.

This is the best approach to do using the data-dismiss attribute.

What is the difference between FragmentPagerAdapter and FragmentStatePagerAdapter?

FragmentPagerAdapter: the fragment of each page the user visits will be stored in memory, although the view will be destroyed. So when the page is visible again, the view will be recreated but the fragment instance is not recreated. This can result in a significant amount of memory being used. FragmentPagerAdapter should be used when we need to store the whole fragment in memory. FragmentPagerAdapter calls detach(Fragment) on the transaction instead of remove(Fragment).

FragmentStatePagerAdapter: the fragment instance is destroyed when it is not visible to the User, except the saved state of the fragment. This results in using only a small amount of Memory and can be useful for handling larger data sets. Should be used when we have to use dynamic fragments, like fragments with widgets, as their data could be stored in the savedInstanceState.Also it won’t affect the performance even if there are large number of fragments.

Java Scanner String input

When you read in the year month day hour minutes with something like nextInt() it leaves rest of the line in the parser/buffer (even if it is blank) so when you call nextLine() you are reading the rest of this first line.

I suggest you to use instead of scan.nextLine().

What does "while True" mean in Python?

Nothing evaluates to True faster than True. So, it is good if you use while True instead of while 1==1 etc.

Filter an array using a formula (without VBA)

Sounds like you're just trying to do a classic two-column lookup.

Tons of solutions for this, most simple is probably the following (which doesn't require an array formula):


To translate your specific example, you would use:


How to determine if binary tree is balanced?

class Node {
    int data;
    Node left;
    Node right;

    // assign variable with constructor
    public Node(int data) { = data;

public class BinaryTree {

    Node root;

    // get max depth
    public static int maxDepth(Node node) {
        if (node == null)
            return 0;

        return 1 + Math.max(maxDepth(node.left), maxDepth(node.right));

    // get min depth
    public static int minDepth(Node node) {
        if (node == null)
            return 0;

        return 1 + Math.min(minDepth(node.left), minDepth(node.right));

    // return max-min<=1 to check if tree balanced
    public boolean isBalanced(Node node) {

        if (Math.abs(maxDepth(node) - minDepth(node)) <= 1)
            return true;

        return false;

    public static void main(String... strings) {
        BinaryTree tree = new BinaryTree();
        tree.root = new Node(1);
        tree.root.left = new Node(2);
        tree.root.right = new Node(3);

        if (tree.isBalanced(tree.root))
            System.out.println("Tree is balanced");
            System.out.println("Tree is not balanced");

Best implementation for hashCode method for a collection

Here is another JDK 1.7+ approach demonstration with superclass logics accounted. I see it as pretty convinient with Object class hashCode() accounted, pure JDK dependency and no extra manual work. Please note Objects.hash() is null tolerant.

I have not include any equals() implementation but in reality you will of course need it.

import java.util.Objects;

public class Demo {

    public static class A {

        private final String param1;

        public A(final String param1) {
            this.param1 = param1;

        public int hashCode() {
            return Objects.hash(


    public static class B extends A {

        private final String param2;
        private final String param3;

        public B(
            final String param1,
            final String param2,
            final String param3) {

            this.param2 = param2;
            this.param3 = param3;

        public final int hashCode() {
            return Objects.hash(

    public static void main(String [] args) {

        A a = new A("A");
        B b = new B("A", "B", "C");

        System.out.println("A: " + a.hashCode());
        System.out.println("B: " + b.hashCode());


How do I make a div full screen?

Use document height if you want to show it beyond the visible area of browser(scrollable area).

CSS Portion

#foo {

JQuery Portion

$(document).ready(function() {
       width: $(document).width(),
       height: $(document).height()

Command line input in Python

It is not at all clear what the OP meant (even after some back-and-forth in the comments), but here are two answers to possible interpretations of the question:

For interactive user input (or piped commands or redirected input)

Use raw_input in Python 2.x, and input in Python 3. (These are built in, so you don't need to import anything to use them; you just have to use the right one for your version of python.)

For example:

user_input = raw_input("Some input please: ")

More details can be found here.

So, for example, you might have a script that looks like this

# First, do some work, to show -- as requested -- that
# the user input doesn't need to come first.
from __future__ import print_function
var1 = 'tok'
var2 = 'tik'+var1
print(var1, var2)

# Now ask for input
user_input = raw_input("Some input please: ") # or `input("Some...` in python 3

# Now do something with the above

If you saved this in, you could just call the script from the command line, it would print out tok tiktok, then ask you for input. You could enter bar baz (followed by the enter key) and it would print bar baz. Here's what that would look like:

$ python
tok tiktok
Some input please: bar baz
bar baz

Here, $ represents the command-line prompt (so you don't actually type that), and I hit Enter after typing bar baz when it asked for input.

For command-line arguments

Suppose you have a script named and want to call it with arguments bar and baz from the command line like

$ bar baz

(Again, $ represents the command-line prompt.) Then, you can do that with the following in your script:

import sys
arg1 = sys.argv[1]
arg2 = sys.argv[2]

Here, the variable arg1 will contain the string 'bar', and arg2 will contain 'baz'. The object sys.argv is just a list containing everything from the command line. Note that sys.argv[0] is the name of the script. And if, for example, you just want a single list of all the arguments, you would use sys.argv[1:].

Fastest way to convert string to integer in PHP

I personally feel casting is the prettiest.

$iSomeVar = (int) $sSomeOtherVar;

Should a string like 'Hello' be sent, it will be cast to integer 0. For a string such as '22 years old', it will be cast to integer 22. Anything it can't parse to a number becomes 0.

If you really do NEED the speed, I guess the other suggestions here are correct in assuming that coercion is the fastest.

Passing an array/list into a Python function

When you define your function using this syntax:

def someFunc(*args):
    for x in args
        print x

You're telling it that you expect a variable number of arguments. If you want to pass in a List (Array from other languages) you'd do something like this:

def someFunc(myList = [], *args):
    for x in myList:
        print x

Then you can call it with this:

items = [1,2,3,4,5]


You need to define named arguments before variable arguments, and variable arguments before keyword arguments. You can also have this:

def someFunc(arg1, arg2, arg3, *args, **kwargs):
    for x in args
        print x

Which requires at least three arguments, and supports variable numbers of other arguments and keyword arguments.

What are the rules about using an underscore in a C++ identifier?

Yes, underscores may be used anywhere in an identifier. I believe the rules are: any of a-z, A-Z, _ in the first character and those +0-9 for the following characters.

Underscore prefixes are common in C code -- a single underscore means "private", and double underscores are usually reserved for use by the compiler.

SyntaxError: multiple statements found while compiling a single statement

A (partial) practical work-around is to put things into a throw-away function.


x = 1
x += 1

results in

>>> x = 1
x += 1
  File "<stdin>", line 1
    x += 1

SyntaxError: multiple statements found while compiling a single statement

However, pasting

def abc():
  x = 1
  x += 1


>>> def abc():
  x = 1
  x += 1
>>> abc()

Of course, this is OK for a quick one-off, won't work for everything you might want to do, etc. But then, going to ipython / jupyter qtconsole is probably the next simplest option.

How to load a UIView using a nib file created with Interface Builder

I'm not sure what some of the answers are talking about, but I need to put this answer here for when I search in Google next time. Keywords: "How to load a UIView from a nib" or "How to load a UIView from an NSBundle."

Here's the code almost 100% straight up from the Apress Beginning iPhone 3 book (page 247, "Using The New Table View Cell"):

- (void)viewDidLoad {
    [super viewDidLoad];
    NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:@"Blah"
                                                 owner:self options:nil];
    Blah *blah;
    for (id object in bundle) {
        if ([object isKindOfClass:[Blah class]]) {
            blah = (Blah *)object;
    assert(blah != nil && "blah can't be nil");
    [self.view addSubview: blah];

This supposes you have a UIView subclass called Blah, a nib called Blah which contains a UIView which has its class set to Blah.

Category: NSObject+LoadFromNib

#import "NSObject+LoadFromNib.h"

@implementation NSObject (LoadFromNib)

+ (id)loadFromNib:(NSString *)name classToLoad:(Class)classToLoad {
    NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:name owner:self options:nil];
    for (id object in bundle) {
        if ([object isKindOfClass:classToLoad]) {
            return object;
    return nil;


Swift Extension

extension UIView {
    class func loadFromNib<T>(withName nibName: String) -> T? {
        let nib  = UINib.init(nibName: nibName, bundle: nil)
        let nibObjects = nib.instantiate(withOwner: nil, options: nil)
        for object in nibObjects {
            if let result = object as? T {
                return result
        return nil

And an example in use:

class SomeView: UIView {
    class func loadFromNib() -> SomeView? {
        return self.loadFromNib(withName: "SomeView")

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

Pretty easy to do this across multiple cells, without having to add '%' to each individually.

Select all the cells you want to change to percent, right Click, then format Cells, choose Custom. Type in 0.0\%.

How can I add a vertical scrollbar to my div automatically?

You need to assign some height to make the overflow: auto; property work.
For testing purpose, add height: 100px; and check.
and also it will be better if you give overflow-y:auto; instead of overflow: auto;, because this makes the element to scroll only vertical but not horizontal.

overflow-y: auto;
height: 100px;

If you don't know the height of the container and you want to show vertical scrollbar when the container reaches a fixed height say 100px, use max-height instead of height property.

For more information, read this MDN article. cannot open shared object file.

Possibly you want to specify PATH — and also ORACLE_HOME and LD_LIBRARY_PATH — so that cron(1) knows where to find binaries.
Read "5 Crontab environment" here.

Table column sizing

Disclaimer: This answer may be a bit old. Since the bootstrap 4 beta. Bootstrap has changed since then.

The table column size class has been changed from this

<th class="col-sm-3">3 columns wide</th>


<th class="col-3">3 columns wide</th>

Scp command syntax for copying a folder from local machine to a remote server

In stall PuTTY in our system and set the environment variable PATH Pointing to putty path. open the command prompt and move to putty folder. Using PSCP command

Please check this

How do I use sudo to redirect output to a location I don't have permission to write to?

How about writing a script?

Filename: myscript


/bin/ls -lah /root > /root/test.out

# end script

Then use sudo to run the script:

sudo ./myscript

How to check if IEnumerable is null or empty?

Take a look at this opensource library: Nzr.ToolBox

public static bool IsEmpty(this System.Collections.IEnumerable enumerable)

Getting a browser's name client-side

EDIT: Since the answer is not valid with newer versions of jquery As jQuery.browser is deprecated in ver 1.9, So Use Jquery Migrate Plugin for that matter.

Original Answer


jQuery.browser and jQuery.browser.version

is your way to go...

How can I find out what version of git I'm running?

Or even just

git version

Results in something like

git version 1.8.3.msysgit.0

JPanel vs JFrame in Java

JFrame is the window; it can have one or more JPanel instances inside it. JPanel is not the window.

You need a Swing tutorial:

How to insert a row between two rows in an existing excel with HSSF (Apache POI)

I merged some of the other answers and comments in the following implementation, tested with Apache POI v3.9.

I have only one rownum parameter because I shift down the target row and copy it in the new empty row. Formulas are handled as expected, they are not copied verbatim, with one exception: references to cells that are above the copied line are not updated; the workaround is to replace these explicit references (if any) with references calculated using INDIRECT() as suggested by this post.

protected void copyRow(Sheet worksheet, int rowNum) {
    Row sourceRow = worksheet.getRow(rowNum);

    //Save the text of any formula before they are altered by row shifting
    String[] formulasArray = new String[sourceRow.getLastCellNum()];
    for (int i = 0; i < sourceRow.getLastCellNum(); i++) {
        if (sourceRow.getCell(i) != null && sourceRow.getCell(i).getCellType() == Cell.CELL_TYPE_FORMULA) 
            formulasArray[i] = sourceRow.getCell(i).getCellFormula();

    worksheet.shiftRows(rowNum, worksheet.getLastRowNum(), 1);
    Row newRow = sourceRow;  //Now sourceRow is the empty line, so let's rename it
    sourceRow = worksheet.getRow(rowNum + 1);  //Now the source row is at rowNum+1

    // Loop through source columns to add to new row
    for (int i = 0; i < sourceRow.getLastCellNum(); i++) {
        // Grab a copy of the old/new cell
        Cell oldCell = sourceRow.getCell(i);
        Cell newCell;

        // If the old cell is null jump to next cell
        if (oldCell == null) {
        } else {
            newCell = newRow.createCell(i);

        // Copy style from old cell and apply to new cell
        CellStyle newCellStyle = worksheet.getWorkbook().createCellStyle();

        // If there is a cell comment, copy
        if (oldCell.getCellComment() != null) {

        // If there is a cell hyperlink, copy
        if (oldCell.getHyperlink() != null) {

        // Set the cell data type

        // Set the cell data value
        switch (oldCell.getCellType()) {
            case Cell.CELL_TYPE_BLANK:
            case Cell.CELL_TYPE_BOOLEAN:
            case Cell.CELL_TYPE_ERROR:
            case Cell.CELL_TYPE_FORMULA:
            case Cell.CELL_TYPE_NUMERIC:
            case Cell.CELL_TYPE_STRING:

    // If there are any merged regions in the source row, copy to new row
    for (int i = 0; i < worksheet.getNumMergedRegions(); i++) {
        CellRangeAddress cellRangeAddress = worksheet.getMergedRegion(i);
        if (cellRangeAddress.getFirstRow() == sourceRow.getRowNum()) {
            CellRangeAddress newCellRangeAddress = new CellRangeAddress(newRow.getRowNum(),
                    (newRow.getRowNum() +
                            (cellRangeAddress.getLastRow() - cellRangeAddress.getFirstRow()

I'm using this implementation in production code.

Android - how to replace part of a string by another string?

In kotlin there is no replaceAll, so I created this loop to replace repeated values ??in a string or any variable.

 var someValue = ""
    while (someValue.contains(".")) {
        someValue = someValue.replace(".", "")
Log.d("newValue :", someValue)
// in that case the stitches have been removed

IE8 support for CSS Media Query

Internet Explorer versions before IE9 do not support media queries.

If you are looking for a way of degrading the design for IE8 users, you may find IE's conditional commenting helpful. Using this, you can specify an IE 8/7/6 specific style sheet which over writes the previous rules.

For example:

<link rel="stylesheet" type="text/css" media="all" href="style.css"/>
<!--[if lt IE 9]>
<link rel="stylesheet" type="text/css" media="all" href="style-ie.css"/>

This won't allow for a responsive design in IE8, but could be a simpler and more accessible solution than using a JS plugin.

How to upgrade PowerShell version from 2.0 to 3.0

As of today, Windows PowerShell 5.1 is the latest version. It can be installed as part of Windows Management Framework 5.1. It was released in January 2017.

Quoting from the official Microsoft download page here.

Some of the new and updated features in this release include:

  • Constrained file copying to/from JEA endpoints
  • JEA support for Group Managed Service Accounts and Conditional Access Policies
  • PowerShell console support for VT100 and redirecting stdin with interactive input
  • Support for catalog signed modules in PowerShell Get
  • Specifying which module version to load in a script
  • Package Management cmdlet support for proxy servers
  • PowerShellGet cmdlet support for proxy servers
  • Improvements in PowerShell Script Debugging
  • Improvements in Desired State Configuration (DSC)
  • Improved PowerShell usage auditing using Transcription and Logging
  • New and updated cmdlets based on community feedback

Fill SVG path element with a background-image

You can do it by making the background into a pattern:

  <pattern id="img1" patternUnits="userSpaceOnUse" width="100" height="100">
    <image href="wall.jpg" x="0" y="0" width="100" height="100" />

Adjust the width and height according to your image, then reference it from the path like this:

<path d="M5,50
         l0,100 l100,0 l0,-100 l-100,0
         a50,50 0 1 1 -100,0 50,50 0 1 1 100,0
         l50,100 l-100,0 l50,-100
  fill="url(#img1)" />

Working example

How to check if field is null or empty in MySQL?

Try using nullif:

SELECT ifnull(nullif(field1,''),'empty') AS field1
  FROM tablename;

How to send a PUT/DELETE request in jQuery?

If you need to make a $.post work to a Laravel Route::delete or Route::put just add an argument "_method"="delete" or "_method"="put".

$.post("your/uri/here", {"arg1":"value1",...,"_method":"delete"}, function(data){}); ...

Must works for others Frameworks

Note: Tested with Laravel 5.6 and jQuery 3

Does MySQL foreign_key_checks affect the entire database?

As explained by Ron, there are two variables, local and global. The local variable is always used, and is the same as global upon connection.


SHOW Variables WHERE Variable_name='foreign_key_checks'; # always shows local variable

When setting the GLOBAL variable, the local one isn't changed for any existing connections. You need to reconnect or set the local variable too.

Perhaps unintuitive, MYSQL does not enforce foreign keys when FOREIGN_KEY_CHECKS are re-enabled. This makes it possible to create an inconsistent database even though foreign keys and checks are on.

If you want your foreign keys to be completely consistent, you need to add the keys while checking is on.

React onClick function fires on render

Instead of calling the function, bind the value to the function:

this.props.removeTaskFunction.bind(this, todo)

MDN ref:

How do I send a POST request with PHP?

Here is using just one command without cURL. Super simple.

echo file_get_contents('', false, stream_context_create([
    'http' => [
        'method' => 'POST',
        'header'  => "Content-type: application/x-www-form-urlencoded",
        'content' => http_build_query([
            'key1' => 'Hello world!', 'key2' => 'second value'

Creating a textarea with auto-resize

Accepted answer is working fine. But that is lot of code for this simple functionality. The below code will do the trick.

   $(document).on("keypress", "textarea", function (e) {
    var height = $(this).css("height");
    var iScrollHeight = $(this).prop("scrollHeight");

What does "fatal: bad revision" mean?

I had a similar issue with Intellij. The issue was that someone added the file that I am trying to compare in Intellij to .gitignore, without actually deleting the file from Git.

How to trigger the window resize event in JavaScript?

Where possible, I prefer to call the function rather than dispatch an event. This works well if you have control over the code you want to run, but see below for cases where you don't own the code.

window.onresize = doALoadOfStuff;

function doALoadOfStuff() {
    //do a load of stuff

In this example, you can call the doALoadOfStuff function without dispatching an event.

In your modern browsers, you can trigger the event using:

window.dispatchEvent(new Event('resize'));

This doesn't work in Internet Explorer, where you'll have to do the longhand:

var resizeEvent = window.document.createEvent('UIEvents'); 
resizeEvent.initUIEvent('resize', true, false, window, 0); 

jQuery has the trigger method, which works like this:


And has the caveat:

Although .trigger() simulates an event activation, complete with a synthesized event object, it does not perfectly replicate a naturally-occurring event.

You can also simulate events on a specific element...

function simulateClick(id) {
  var event = new MouseEvent('click', {
    'view': window,
    'bubbles': true,
    'cancelable': true

  var elem = document.getElementById(id); 

  return elem.dispatchEvent(event);

Which is preferred: Nullable<T>.HasValue or Nullable<T> != null?

In VB.Net. Do NOT use "IsNot Nothing" when you can use ".HasValue". I just solved an "Operation could destabilize the runtime" Medium trust error by replacing "IsNot Nothing" with ".HasValue" In one spot. I don't really understand why, but something is happening differently in the compiler. I would assume that "!= null" in C# may have the same issue.

Extract code country from phone number [libphonenumber]

Use a try catch block like below:

try { 

const phoneNumber = this.phoneUtil.parseAndKeepRawInput(value, this.countryCode);


How to git ignore subfolders / subdirectories?

To exclude content and subdirectories:


To just exclude all subdirectories but take the content, add "/":


phpmysql error - #1273 - #1273 - Unknown collation: 'utf8mb4_general_ci'

You can fix this issue by deleting browser cookie from the begining of time. I have tried this and it is working fine for me.

To delete only cookies:

  1. hold down ctrl+shift+delete
  2. remove all check boxes except for cookies of course
  3. use the drop down on top to select "from the beginning of time
  4. click clear browsing data

Can I use return value of INSERT...RETURNING in another INSERT?

You can do so starting with Postgres 9.1:

with rows as (
INSERT INTO Table1 (name) VALUES ('a_title') RETURNING id
INSERT INTO Table2 (val)
FROM rows

In the meanwhile, if you're only interested in the id, you can do so with a trigger:

create function t1_ins_into_t2()
  returns trigger
as $$
  insert into table2 (val) values (;
  return new;
$$ language plpgsql;

create trigger t1_ins_into_t2
  after insert on table1
for each row
execute procedure t1_ins_into_t2();

How to describe "object" arguments in jsdoc?

From the @param wiki page:

Parameters With Properties

If a parameter is expected to have a particular property, you can document that immediately after the @param tag for that parameter, like so:

  * @param userInfo Information about the user.
  * @param The name of the user.
  * @param The email of the user.
 function logIn(userInfo) {

There used to be a @config tag which immediately followed the corresponding @param, but it appears to have been deprecated (example here).

Resolve conflicts using remote changes when pulling from Git remote

You can either use the answer from the duplicate link pointed by nvm.

Or you can resolve conflicts by using their changes (but some of your changes might be kept if they don't conflict with remote version):

git pull -s recursive -X theirs

How to set environment variables in Jenkins?

You can use either of the following ways listed below:

  1. Use Env Inject Plugin for creating environment variables. Follow this for usage and more details
    1. Navigate below and can add

Manage Jenkins -> Configure System -> Global Properties -> Environment Variables -> Add

enter image description here

Convert cells(1,1) into "A1" and vice versa

The Address property of a cell can get this for you:

MsgBox Cells(1, 1).Address(RowAbsolute:=False, ColumnAbsolute:=False)

returns A1.

The other way around can be done with the Row and Column property of Range:

MsgBox Range("A1").Row & ", " & Range("A1").Column

returns 1,1.

How to write PNG image to string with the PIL?

sth's solution didn't work for me
because in ...

Imaging/PIL/Image.pyc line 1423 -> raise KeyError(ext) # unknown extension

It was trying to detect the format from the extension in the filename , which doesn't exist in StringIO case

You can bypass the format detection by setting the format yourself in a parameter

import StringIO
output = StringIO.StringIO()
format = 'PNG' # or 'JPEG' or whatever you want, format)
contents = output.getvalue()

How to convert numbers to words without using num2word library?

This Did the job for me(Python 2.x)

nums = {1:"One", 2:"Two", 3:"Three" ,4:"Four", 5:"Five", 6:"Six", 7:"Seven", 8:"Eight",\
        9:"Nine", 0:"Zero", 10:"Ten", 11:"Eleven", 12:"Tweleve" , 13:"Thirteen", 14:"Fourteen", \
        15: "Fifteen", 16:"Sixteen", 17:"Seventeen", 18:"Eighteen", 19:"Nineteen", 20:"Twenty", 30:"Thirty", 40:"Forty", 50:"Fifty",\
        60:"Sixty", 70:"Seventy", 80:"Eighty", 90:"Ninety"}
num = input("Enter a number: ")
# To convert three digit number into words 
if 100 <= num < 1000:
    a = num / 100
    b = num % 100
    c = b / 10
    d = b % 10
    if c == 1 :
        print nums[a] + "hundred" , nums[b]
    elif c == 0:
        print nums[a] + "hundred" , nums[d]
        c *= 10
        if d == 0:
            print nums[a] + "hundred", nums[c]
            print nums[a] + "hundred" , nums[c], nums[d]
# to convert two digit number into words            
elif 0 <= num < 100:
    a = num / 10
    b = num % 10
    if a == 1:
        print nums[num]
        a *= 10
        print nums[a], nums[b]

how do I create an array in jquery?

I haven't been using jquery for a while but you might be looking for this:


JavaScript: How to get parent element by selector?

Here's a recursive solution:

function closest(el, selector, stopSelector) {
  if(!el || !el.parentElement) return null
  else if(stopSelector && el.parentElement.matches(stopSelector)) return null
  else if(el.parentElement.matches(selector)) return el.parentElement
  else return closest(el.parentElement, selector, stopSelector)

Save matplotlib file to a directory

Here's the piece of code that saves plot to the selected directory. If the directory does not exist, it is created.

import os
import matplotlib.pyplot as plt

script_dir = os.path.dirname(__file__)
results_dir = os.path.join(script_dir, 'Results/')
sample_file_name = "sample"

if not os.path.isdir(results_dir):

plt.ylabel('some numbers')
plt.savefig(results_dir + sample_file_name)

How to select all textareas and textboxes using jQuery?

$('input[type=text], textarea').css({width: '90%'});

That uses standard CSS selectors, jQuery also has a set of pseudo-selector filters for various form elements, for example:

$(':text').css({width: '90%'});

will match all <input type="text"> elements. See Selectors documentation for more info.

Why does the order in which libraries are linked sometimes cause errors in GCC?

You may can use -Xlinker option.

g++ -o foobar  -Xlinker -start-group  -Xlinker libA.a -Xlinker libB.a -Xlinker libC.a  -Xlinker -end-group 

is ALMOST equal to

g++ -o foobar  -Xlinker -start-group  -Xlinker libC.a -Xlinker libB.a -Xlinker libA.a  -Xlinker -end-group 

Careful !

  1. The order within a group is important ! Here's an example: a debug library has a debug routine, but the non-debug library has a weak version of the same. You must put the debug library FIRST in the group or you will resolve to the non-debug version.
  2. You need to precede each library in the group list with -Xlinker

UIAlertView first deprecated IOS 9

Use UIAlertController instead of UIAlertView

-(void)showMessage:(NSString*)message withTitle:(NSString *)title
UIAlertController * alert=   [UIAlertController

UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){

    //do something when click button
[alert addAction:okAction];
UIViewController *vc = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
[vc presentViewController:alert animated:YES completion:nil];

Listing all permutations of a string/integer

I hope this will suffice:

using System;
public class Program
    public static void Main()
        //Example using word cat

static void permute(string word){
    for(int i=0; i < word.Length; i++){
        char start = word[0];
        for(int j=1; j < word.Length; j++){
            string left = word.Substring(1,j-1);
            string right = word.Substring(j);
        if(i+1 < word.Length){
            word = wordChange(word, i + 1);

static string wordChange(string word, int index){
    string newWord = "";
    for(int i=0; i<word.Length; i++){
        if(i== 0)
            newWord += word[index];
        else if(i== index)
            newWord += word[0];
            newWord += word[i];
    return newWord;



Selecting Values from Oracle Table Variable / Array?


In Oracle these are created once and then when invoked the data is private to your session.

Oracle Documentation Link

Try something like this...

   ( number_column   NUMBER( 10, 0 )

   INSERT INTO temp_number
      ( number_column )
      ( select distinct sgbstdn_pidm 
          from sgbstdn 
         where sgbstdn_majr_code_1 = 'HS04' 
           and sgbstdn_program_1 = 'HSCOMPH' 

    FOR pidms_rec IN ( SELECT number_column FROM temp_number )
        -- Do something here
    END LOOP; 

Get startup type of Windows service using PowerShell

As far as I know there is no “native” PowerShell way of getting this information. And perhaps it is rather the .NET limitation than PowerShell.

Here is the suggestion to add this functionality to the version next:

The WMI workaround is also there, just in case. I use this WMI solution for my tasks and it works.

Function to convert timestamp to human date in javascript

Here are the simple ways to every date format confusions:

for current date:

var current_date=new Date();

to get the Timestamp of current date:

var timestamp=new Date().getTime();

to convert a particular Date into Timestamp:

var timestamp_formation=new Date('mm/dd/yyyy').getTime();

to convert timestamp into Date:

    var timestamp=new Date('02/10/2016').getTime();
    var todate=new Date(timestamp).getDate();
    var tomonth=new Date(timestamp).getMonth()+1;
    var toyear=new Date(timestamp).getFullYear();
    var original_date=tomonth+'/'+todate+'/'+toyear;


How to get an element's top position relative to the browser's viewport?

function inViewport(element) {
    let bounds = element.getBoundingClientRect();
    let viewWidth = document.documentElement.clientWidth;
    let viewHeight = document.documentElement.clientHeight;

    if (bounds['left'] < 0) return false;
    if (bounds['top'] < 0) return false;
    if (bounds['right'] > viewWidth) return false;
    if (bounds['bottom'] > viewHeight) return false;

    return true;


MySQL: Selecting multiple fields into multiple variables in a stored procedure

Your syntax isn't quite right: you need to list the fields in order before the INTO, and the corresponding target variables after:

SELECT Id, dateCreated
INTO iId, dCreate
FROM products
WHERE pName = iName

How to get current user, and how to use User class in MVC5?

If you're coding in an ASP.NET MVC Controller, use

using Microsoft.AspNet.Identity;



Worth mentioning that User.Identity.IsAuthenticated and User.Identity.Name will work without adding the above mentioned using statement. But GetUserId() won't be present without it.

If you're in a class other than a Controller, use


In the default template of MVC 5, user ID is a GUID stored as a string.

No best practice yet, but found some valuable info on extending the user profile:

How to retrieve form values from HTTPPOST, dictionary or?

You could have your controller action take an object which would reflect the form input names and the default model binder will automatically create this object for you:

public ActionResult SubmitAction(SomeModel model)
    var value1 = model.SimpleProp1;
    var value2 = model.SimpleProp2;
    var value3 = model.ComplexProp1.SimpleProp1;

    ... return something ...

Another (obviously uglier) way is:

public ActionResult SubmitAction()
    var value1 = Request["SimpleProp1"];
    var value2 = Request["SimpleProp2"];
    var value3 = Request["ComplexProp1.SimpleProp1"];

    ... return something ...

What’s the best way to load a JSONObject from a json text file?

Another way of doing the same could be using the Gson Class

String filename = "path/to/file/abc.json";
Gson gson = new Gson();
JsonReader reader = new JsonReader(new FileReader(filename));
SampleClass data = gson.fromJson(reader, SampleClass.class);

This will give an object obtained after parsing the json string to work with.

make div's height expand with its content

as an alternative way you can also try this that may be usefull in some situations



PHP: HTML: send HTML select option attribute in POST

You can do this with JQuery


   <form name='add'>
   Age: <select id="age" name='age'>
   <option value='1' stud_name='sre'>23</option>
   <option value='2' stud_name='sam'>24</option>
   <option value='5' stud_name='john'>25</option>
   <input type='hidden' id="name" name="name" value=""/>
   <input type='submit' name='submit'/>

Add this code in Header section:

<script src=""></script>

Now JQuery function

<script type="text/javascript" language="javascript">
$(function() {
      var studentNmae= $('option:selected', this).attr('stud_name');

you can use both values as

$name = $_POST['name'];
$value = $_POST['age'];

Homebrew: Could not symlink, /usr/local/bin is not writable

For me the solution was to run brew update.


This might be normal practice for people familiar with homebrew, but I'm not one of those people.

Edit: I discovered that I needed to update by running brew doctor as suggested by @kinnth's answer to this same question.

A general troubleshooting workflow might look like this: 1. run brew update 2. if that doesn't help run brew doctor and follow its directions 3. if that doesn't help check stack overflow

Importing larger sql files into MySQL

The question is a few months old but for other people looking --

A simpler way to import a large file is to make a sub directory 'upload' in your folder c:/wamp/apps/phpmyadmin3.5.2 and edit this line in the file in the same directory to include the folder name $cfg['UploadDir'] = 'upload';

Then place the incoming .sql file in the folder /upload.

Working from inside the phpmyadmin console, go to the new database and import. You will now see an additional option to upload files from that folder. Chose the correct file and be a little patient. It works.

If you still get a time out error try adding $cfg['ExecTimeLimit'] = 0; to the same file.

I have had difficulty importing an .sql file where the user name was root and the password differed from my the root password on my new server. I simply took off the password before I exported the .sql file and the import worked smoothly.

Custom edit view in UITableViewCell while swipe left. Objective-C or Swift

Just copy paste the code below!

-(NSArray *)tableView:(UITableView *)tableView editActionsForRowAtIndexPath:(NSIndexPath *)indexPath {

       UITableViewRowAction *editAction = [UITableViewRowAction rowActionWithStyle:UITableViewRowActionStyleNormal title:@"Clona" handler:^(UITableViewRowAction *action, NSIndexPath *indexPath){
          //insert your editAction here
       editAction.backgroundColor = [UIColor blueColor];

       UITableViewRowAction *deleteAction = [UITableViewRowAction rowActionWithStyle:UITableViewRowActionStyleNormal title:@"Delete"  handler:^(UITableViewRowAction *action, NSIndexPath *indexPath){
          //insert your deleteAction here
       deleteAction.backgroundColor = [UIColor redColor];
return @[deleteAction,editAction];

Does "git fetch --tags" include "git fetch"?

Note: starting with git 1.9/2.0 (Q1 2014), git fetch --tags fetches tags in addition to what are fetched by the same command line without the option.

See commit c5a84e9 by Michael Haggerty (mhagger):

Previously, fetch's "--tags" option was considered equivalent to specifying the refspec


on the command line; in particular, it caused the remote.<name>.refspec configuration to be ignored.

But it is not very useful to fetch tags without also fetching other references, whereas it is quite useful to be able to fetch tags in addition to other references.
So change the semantics of this option to do the latter.

If a user wants to fetch only tags, then it is still possible to specifying an explicit refspec:

git fetch <remote> 'refs/tags/*:refs/tags/*'

Please note that the documentation prior to was ambiguous about this aspect of "fetch --tags" behavior.
Commit f0cb2f1 (2012-12-14) fetch --tags made the documentation match the old behavior.
This commit changes the documentation to match the new behavior (see Documentation/fetch-options.txt).

Request that all tags be fetched from the remote in addition to whatever else is being fetched.

Since Git 2.5 (Q2 2015) git pull --tags is more robust:

See commit 19d122b by Paul Tan (pyokagan), 13 May 2015.
(Merged by Junio C Hamano -- gitster -- in commit cc77b99, 22 May 2015)

pull: remove --tags error in no merge candidates case

Since 441ed41 ("git pull --tags": error out with a better message., 2007-12-28, Git 1.5.4+), git pull --tags would print a different error message if git-fetch did not return any merge candidates:

It doesn't make sense to pull all tags; you probably meant:
       git fetch --tags

This is because at that time, git-fetch --tags would override any configured refspecs, and thus there would be no merge candidates. The error message was thus introduced to prevent confusion.

However, since c5a84e9 (fetch --tags: fetch tags in addition to other stuff, 2013-10-30, Git 1.9.0+), git fetch --tags would fetch tags in addition to any configured refspecs.
Hence, if any no merge candidates situation occurs, it is not because --tags was set. As such, this special error message is now irrelevant.

To prevent confusion, remove this error message.

With Git 2.11+ (Q4 2016) git fetch is quicker.

See commit 5827a03 (13 Oct 2016) by Jeff King (peff).
(Merged by Junio C Hamano -- gitster -- in commit 9fcd144, 26 Oct 2016)

fetch: use "quick" has_sha1_file for tag following

When fetching from a remote that has many tags that are irrelevant to branches we are following, we used to waste way too many cycles when checking if the object pointed at by a tag (that we are not going to fetch!) exists in our repository too carefully.

This patch teaches fetch to use HAS_SHA1_QUICK to sacrifice accuracy for speed, in cases where we might be racy with a simultaneous repack.

Here are results from the included perf script, which sets up a situation similar to the one described above:

Test            HEAD^               HEAD
5550.4: fetch   11.21(10.42+0.78)   0.08(0.04+0.02) -99.3%

That applies only for a situation where:

  1. You have a lot of packs on the client side to make reprepare_packed_git() expensive (the most expensive part is finding duplicates in an unsorted list, which is currently quadratic).
  2. You need a large number of tag refs on the server side that are candidates for auto-following (i.e., that the client doesn't have). Each one triggers a re-read of the pack directory.
  3. Under normal circumstances, the client would auto-follow those tags and after one large fetch, (2) would no longer be true.
    But if those tags point to history which is disconnected from what the client otherwise fetches, then it will never auto-follow, and those candidates will impact it on every fetch.

Git 2.21 (Feb. 2019) seems to have introduced a regression when the config remote.origin.fetch is not the default one ('+refs/heads/*:refs/remotes/origin/*')

fatal: multiple updates for ref 'refs/tags/v1.0.0' not allowed

Git 2.24 (Q4 2019) adds another optimization.

See commit b7e2d8b (15 Sep 2019) by Masaya Suzuki (draftcode).
(Merged by Junio C Hamano -- gitster -- in commit 1d8b0df, 07 Oct 2019)

fetch: use oidset to keep the want OIDs for faster lookup

During git fetch, the client checks if the advertised tags' OIDs are already in the fetch request's want OID set.
This check is done in a linear scan.
For a repository that has a lot of refs, repeating this scan takes 15+ minutes.

In order to speed this up, create a oid_set for other refs' OIDs.

Difference between Iterator and Listiterator?

There are two differences:

  1. We can use Iterator to traverse Set and List and also Map type of Objects. While a ListIterator can be used to traverse for List-type Objects, but not for Set-type of Objects.

    That is, we can get a Iterator object by using Set and List, see here:

    By using Iterator we can retrieve the elements from Collection Object in forward direction only.

    Methods in Iterator:

    1. hasNext()
    2. next()
    3. remove()
    Iterator iterator = Set.iterator();
    Iterator iterator = List.iterator();
  2. But we get ListIterator object only from the List interface, see here:

    where as a ListIterator allows you to traverse in either directions (Both forward and backward). So it has two more methods like hasPrevious() and previous() other than those of Iterator. Also, we can get indexes of the next or previous elements (using nextIndex() and previousIndex() respectively )

    Methods in ListIterator:

    1. hasNext()
    2. next()
    3. previous()
    4. hasPrevious()
    5. remove()
    6. nextIndex()
    7. previousIndex()
    ListIterator listiterator = List.listIterator();

    i.e., we can't get ListIterator object from Set interface.

Reference : - What is the difference between Iterator and ListIterator ?

How to create a temporary directory?

Here is a simple explanation about how to create a temp dir using templates.

  1. Creates a temporary file or directory, safely, and prints its name.
  2. TEMPLATE must contain at least 3 consecutive 'X's in last component.
  3. If TEMPLATE is not specified, it will use tmp.XXXXXXXXXX
  4. directories created are u+rwx, minus umask restrictions.

PARENT_DIR=./temp_dirs # (optional) specify a dir for your tempdirs

TEMPLATE_PREFIX='tmp' # prefix of your new tempdir template
TEMPLATE_RANDOM='XXXX' # Increase the Xs for more random characters

# create the tempdir using your custom $TEMPLATE, which may include
# a path such as a parent dir, and assign the new path to a var

# create the tempdir in parent dir, using default template
# 'tmp.XXXXXXXXXX' and assign the new path to a var

# create a tempdir in your systems default tmp path e.g. /tmp 
# using the default template 'tmp.XXXXXXXXXX' and assign path to var
NEW_TEMP_DIR_PATH=$(mktemp -d)

# Do whatever you want with your generated temp dir and var holding its path

How to view the dependency tree of a given npm module?

You can use the npm-remote-ls module. You can install it globally:

npm install -g npm-remote-ls

And then call:

npm-remote-ls bower

Alternatively, [email protected] installed then you can use npx and avoid globally installing the command - just call:

npx npm-remote-ls bower

Difference between Date(dateString) and new Date(dateString)

I know this is old but by far the easier solution is to just use

var temp = new Date("2010-08-17T12:09:36");

How to get the seconds since epoch from the time + date output of gmtime()?

If you got here because a search engine told you this is how to get the Unix timestamp, stop reading this answer. Scroll down one.

If you want to reverse time.gmtime(), you want calendar.timegm().

>>> calendar.timegm(time.gmtime())

You can turn your string into a time tuple with time.strptime(), which returns a time tuple that you can pass to calendar.timegm():

>>> import calendar
>>> import time
>>> calendar.timegm(time.strptime('Jul 9, 2009 @ 20:02:58 UTC', '%b %d, %Y @ %H:%M:%S UTC'))

More information about calendar module here

How to debug a GLSL shader?

The GLSL Shader source code is compiled and linked by the graphics driver and executed on the GPU.
If you want to debug the shader, then you have to use graphics debugger like RenderDoc or NVIDIA Nsight.

when I run mockito test occurs WrongTypeOfReturnValue Exception

For me this meant I was running this:

a = Mockito.mock(SomeClass.class);
b = new RealClass();
// within this method1, it calls param1.method2() -- note, b is not a spy or mock

So what was happening is that mockito was detecting that a.method2() was being called, and telling me I couldn't return c from a.method2() which is wrong.

Fix: use the doReturn(c).when(b).method1(a) style syntax (instead of when(b.method1(a)).thenReturn(c);), which will help you discover the hidden bug more concisely and quickly.

Or in this particular case, after doing that it started showing the more accurate "NotAMockException", and I changed it to not longer try to set a return value from a non-mock object.

JavaScript: Object Rename Key

I'd do something like this:

function renameKeys(dict, keyMap) {
  return _.reduce(dict, function(newDict, val, oldKey) {
    var newKey = keyMap[oldKey] || oldKey
    newDict[newKey] = val 
    return newDict
  }, {})

How to get the path of src/test/resources directory in JUnit?

You can't use a file from a resource folder for tests in a common case. The reason is that resource files in the resource folder are stored inside a jar. So they don't have a real path in the file system.

The most simple solution can be:

  1. Copy a file from resources to the temporary folder and get a path to that temporary file.
  2. Do tests using a temporary path.
  3. Delete the temporary file.

TemporaryFolder from JUnit can be used to create temporary files and delete it after test is complited. Classes from guava library are used to copy a file form resource folder.

Please, notice that if we use a subfolder in the resources folder, like good one, we don't have to add leading / to the resource path.

public class SomeTest {

    public TemporaryFolder tmpFolder = new TemporaryFolder();

    public void doSomethinge() throws IOException {
        File file = createTmpFileFromResource(tmpFolder, "file.txt");
        File goodFile = createTmpFileFromResource(tmpFolder, "good/file.txt");

        // do testing here

    private static File createTmpFileFromResource(TemporaryFolder folder,
                                                  String classLoaderResource) throws IOException {
        URL resource = Resources.getResource(classLoaderResource);

        File tmpFile = folder.newFile();
        return tmpFile;


How to check whether particular port is open or closed on UNIX?

Try (maybe as root)

lsof -i -P

and grep the output for the port you are looking for.

For example to check for port 80 do

lsof -i -P | grep :80

How to get a ListBox ItemTemplate to stretch horizontally the full width of the ListBox?

I'm sure this is a duplicate, but I can't find a question with the same answer.

Add HorizontalContentAlignment="Stretch" to your ListBox. That should do the trick. Just be careful with auto-complete because it is so easy to get HorizontalAlignment by mistake.

PDO support for multiple queries (PDO_MYSQL, PDO_MYSQLND)

A quick-and-dirty approach:

function exec_sql_from_file($path, PDO $pdo) {
    if (! preg_match_all("/('(\\\\.|.)*?'|[^;])+/s", file_get_contents($path), $m))

    foreach ($m[0] as $sql) {
        if (strlen(trim($sql)))

Splits at reasonable SQL statement end points. There is no error checking, no injection protection. Understand your use before using it. Personally, I use it for seeding raw migration files for integration testing.

Getting the value of an attribute in XML

This is more of an xpath question, but like this, assuming the context is the parent element:

<xsl:value-of select="name/@attribute1" />

Node.js res.setHeader('content-type', 'text/javascript'); pushing the response javascript as file download

You can directly set the content type like below:

res.writeHead(200, {'Content-Type': 'text/plain'});

For reference go through the nodejs Docs link.

Escaping special characters in Java Regular Expressions

The Pattern.quote(String s) sort of does what you want. However it leaves a little left to be desired; it doesn't actually escape the individual characters, just wraps the string with \Q...\E.

There is not a method that does exactly what you are looking for, but the good news is that it is actually fairly simple to escape all of the special characters in a Java regular expression:

regex.replaceAll("[\\W]", "\\\\$0")

Why does this work? Well, the documentation for Pattern specifically says that its permissible to escape non-alphabetic characters that don't necessarily have to be escaped:

It is an error to use a backslash prior to any alphabetic character that does not denote an escaped construct; these are reserved for future extensions to the regular-expression language. A backslash may be used prior to a non-alphabetic character regardless of whether that character is part of an unescaped construct.

For example, ; is not a special character in a regular expression. However, if you escape it, Pattern will still interpret \; as ;. Here are a few more examples:

  • > becomes \> which is equivalent to >
  • [ becomes \[ which is the escaped form of [
  • 8 is still 8.
  • \) becomes \\\) which is the escaped forms of \ and ( concatenated.

Note: The key is is the definition of "non-alphabetic", which in the documentation really means "non-word" characters, or characters outside the character set [a-zA-Z_0-9].

Use placeholders in yaml


  • YAML version 1.2
  • user wishes to
    • include variable placeholders in YAML
    • have placeholders replaced with computed values, upon yaml.load
    • be able to use placeholders for both YAML mapping keys and values


  • YAML does not natively support variable placeholders.
  • Anchors and Aliases almost provide the desired functionality, but these do not work as variable placeholders that can be inserted into arbitrary regions throughout the YAML text. They must be placed as separate YAML nodes.
  • There are some add-on libraries that support arbitrary variable placeholders, but they are not part of the native YAML specification.


Consider the following example YAML. It is well-formed YAML syntax, however it uses (non-standard) curly-brace placeholders with embedded expressions.

The embedded expressions do not produce the desired result in YAML, because they are not part of the native YAML specification. Nevertheless, they are used in this example only to help illustrate what is available with standard YAML and what is not.

  cust_fname:   "Homer"
  cust_lname:   "Himpson"
  cust_motto:   "I love donuts!"
  cust_email:   [email protected]

  govt_sales_taxrate: 1.15

  prch_unit_label:    "Bacon-Wrapped Fancy Glazed Donut"
  prch_unit_price:    3.00
  prch_unit_quant:    7
  prch_product_cost:  "{{prch_unit_price * prch_unit_quant}}"
  prch_total_cost:    "{{prch_product_cost * govt_sales_taxrate}}"   

  cust_fname:   "{{cust_fname}}"
  cust_lname:   "{{cust_lname}}"
  ship_city:    Houston
  ship_state:   Hexas    

  cust_email:     "{{cust_email}}"
  mail_subject:   Thanks for your DoughNutz order!
  mail_notes: |
    We want the mail_greeting to have all the expected values
    with filled-in placeholders (and not curly-braces).
  mail_greeting: |
    Greetings {{cust_fname}} {{cust_lname}}!
    We love your motto "{{cust_motto}}" and we agree with you!
    Your total purchase price is {{prch_total_cost}}


  • The substitutions marked in GREEN are readily available in standard YAML, using anchors, aliases, and merge keys.

  • The substitutions marked in YELLOW are technically available in standard YAML, but not without a custom type declaration, or some other binding mechanism.

  • The substitutions marked in RED are not available in standard YAML. Yet there are workarounds and alternatives; such as through string formatting or string template engines (such as python's str.format).

Image explaining the different types of variable substitution in YAML


A frequently-requested feature for YAML is the ability to insert arbitrary variable placeholders that support arbitrary cross-references and expressions that relate to the other content in the same (or transcluded) YAML file(s).

YAML supports anchors and aliases, but this feature does not support arbitrary placement of placeholders and expressions anywhere in the YAML text. They only work with YAML nodes.

YAML also supports custom type declarations, however these are less common, and there are security implications if you accept YAML content from potentially untrusted sources.

YAML addon libraries

There are YAML extension libraries, but these are not part of the native YAML spec.


  • Use YAML in conjunction with a template system, such as Jinja2 or Twig
  • Use a YAML extension library
  • Use sprintf or str.format style functionality from the hosting language


  • YTT YAML Templating essentially a fork of YAML with additional features that may be closer to the goal specified in the OP.
  • Jsonnet shares some similarity with YAML, but with additional features that may be closer to the goal specified in the OP.

See also

Here at SO

Outside SO

TypeError: Router.use() requires middleware function but got a Object

If your are using express above 2.x, you have to declare app.router like below code. Please try to replace your code

app.use('/', routes);



Please click here to get more details about app.router


app.router is depreciated in express 3.0+. If you are using express 3.0+, refer to Anirudh's answer below.

How do I combine the first character of a cell with another cell in Excel?

Not sure why no one is using semicolons. This is how it works for me:


Solutions with comma produce an error in Excel.

How to remove anaconda from windows completely?

Method1: To uninstall Anaconda3 go to the Anaconda3 folder, there u will be able to find an executable called Uninstall-Anaconda3.exe, double click on it. This should uninstall ur application. There are times when the shortcut of anaconda command prompt,jupyter notebook, spyder, etc exists, so delete those files too.

Method2 (Windows8): Go to control panel->Programs->Uninstall a Program and then select Anaconda3(Python3.1. 64-bit)in the menu.

jQuery .load() call doesn't execute JavaScript in loaded HTML file

Tacking onto @efreed answer...

I was using .load('mypage.html #theSelectorIwanted') to call content from a page by selector, but that means it does not execute the inline scripts inside.

Instead, I was able to change my markup so that '#theSelectorIwanted'became it's own file and I used

load('theSelectorIwanted.html`, function() {}); 

and it ran the inline scripts just fine.

Not everyone has that option but this was a quick workaround to get where I wanted!

Convert to/from DateTime and Time in Ruby

You'll need two slightly different conversions.

To convert from Time to DateTime you can amend the Time class as follows:

require 'date'
class Time
  def to_datetime
    # Convert seconds + microseconds into a fractional number of seconds
    seconds = sec + Rational(usec, 10**6)

    # Convert a UTC offset measured in minutes to one measured in a
    # fraction of a day.
    offset = Rational(utc_offset, 60 * 60 * 24), month, day, hour, min, seconds, offset)

Similar adjustments to Date will let you convert DateTime to Time .

class Date
  def to_gm_time
    to_time(new_offset, :gm)

  def to_local_time
    to_time(new_offset(, :local)

  def to_time(dest, method)
    #Convert a fraction of a day to a number of microseconds
    usec = (dest.sec_fraction * 60 * 60 * 24 * (10**6)).to_i
    Time.send(method, dest.year, dest.month,, dest.hour, dest.min,
              dest.sec, usec)

Note that you have to choose between local time and GM/UTC time.

Both the above code snippets are taken from O'Reilly's Ruby Cookbook. Their code reuse policy permits this.

Extract file basename without path and extension in bash

Just an alternative that I came up with to extract an extension, using the posts in this thread with my own small knowledge base that was more familiar to me.

ext="$(rev <<< "$(cut -f "1" -d "." <<< "$(rev <<< "file.docx")")")"

Note: Please advise on my use of quotes; it worked for me but I might be missing something on their proper use (I probably use too many).

IIS sc-win32-status codes

Here's the list of all Win32 error codes. You can use this page to lookup the error code mentioned in IIS logs:

You can also use command line utility net to find information about a Win32 error code. The syntax would be:
net helpmsg Win32_Status_Code

Line Break in HTML Select Option?

Ok i found a solution:


<div class="styled-select">
    <select class="select-css">
        <option disabled selected></option>
    <span>How many kg's per week do you expect to be ordering</span>


.styled-select {
appearance: none;
   height: 80px;
.styled-select {
    appearance: none;
    overflow: hidden;


$(".select-css").on("change", function(){
    $(this).next('span').css('display', 'none');

How to split large text file in windows?

You can use the command split for this task. For example this command entered into the command prompt

split YourLogFile.txt -b 500m

creates several files with a size of 500 MByte each. This will take several minutes for a file of your size. You can rename the output files (by default called "xaa", "xab",... and so on) to *.txt to open it in the editor of your choice.

Make sure to check the help file for the command. You can also split the log file by number of lines or change the name of your output files.

(tested on Windows 7 64 bit)

What's the main difference between int.Parse() and Convert.ToInt32

  • If you've got a string, and you expect it to always be an integer (say, if some web service is handing you an integer in string format), you'd use Int32.Parse().

  • If you're collecting input from a user, you'd generally use Int32.TryParse(), since it allows you more fine-grained control over the situation when the user enters invalid input.

  • Convert.ToInt32() takes an object as its argument. (See Chris S's answer for how it works)

    Convert.ToInt32() also does not throw ArgumentNullException when its argument is null the way Int32.Parse() does. That also means that Convert.ToInt32() is probably a wee bit slower than Int32.Parse(), though in practice, unless you're doing a very large number of iterations in a loop, you'll never notice it.

Oracle client ORA-12541: TNS:no listener

I also faced the same problem but I resolved the issue by starting the TNS listener in control panel -> administrative tools -> services ->oracle TNS listener start.I am using windows Xp and Toad to connect to Oracle.

Write a mode method in Java to find the most frequently occurring element in an array

I know that this question is from a while ago, but I wanted to add an answer that I believe expands upon the original question. The addendum to this question was to write the mode method without relying upon a preset range (in this case, 0 through 100). I have written a version for mode that uses the range of values in the original array to generate the count array.

public static int mode(int[] list) {

    //Initialize max and min value variable as first value of list
    int maxValue = list[0]; 
    int minValue = list[0];

    //Finds maximum and minimum values in list
    for (int i = 1; i < list.length; i++) {
        if (list[i] > maxValue) {
            maxValue = list[i];

        if (list[i] < minValue) {
            minValue = list[i];

    //Initialize count array with (maxValue - minValue + 1) elements  
    int[] count = new int[maxValue - minValue + 1];

    //Tally counts of values from list, store in array count
    for (int i = 0; i < list.length; i++) {
        count[list[i] - minValue]++; //Increment counter index for current value of list[i] - minValue

    //Find max value in count array
    int max = count[0]; //Initialize max variable as first value of count

    for (int i = 1; i < count.length; i++) {
        if (count[i] > max) {
            max = count[i];

    //Find first instance where max occurs in count array
    for (int i = 0; i < count.length; i++) {
        if (count[i] == max) {
            return i + minValue; //Returns index of count adjusted for min/max list values - this is the mode value in list
    return -1; //Only here to force compilation, never actually used

How to fix symbol lookup error: undefined symbol errors in a cluster environment

yum update

helped me out. After I had

wget: symbol lookup error: wget: undefined symbol: psl_latest

How to save a figure in MATLAB from the command line?

imwrite(A,filename) writes image data A to the file specified by filename, inferring the file format from the extension

Breaking out of a for loop in Java

How about

for (int k = 0; k < 10; k = k + 2) {
    if (k == 2) {


The other way is a labelled loop

myloop:  for (int i=0; i < 5; i++) {

              for (int j=0; j < 5; j++) {

                if (i * j > 6) {
                  break myloop;

                System.out.println(i + " " + j);

For an even better explanation you can check here

GDB: break if variable equal value

There are hardware and software watchpoints. They are for reading and for writing a variable. You need to consult a tutorial:

To set a watchpoint, first you need to break the code into a place where the varianle i is present in the environment, and set the watchpoint.

watch command is used to set a watchpoit for writing, while rwatch for reading, and awatch for reading/writing.

Repeat command automatically in Linux

watch is good but will clean the screen.

watch -n 1 'ps aux | grep php'

Bootstrap 4 navbar color

You can just use "!important" to get your custom color

.navbar {
 background-color: yourcolor !important;

Fail to create Android virtual Device, "No system image installed for this Target"

If you use Android Studio .Open the SDK-Manager, checked "Show Package Details" you will find out "Android Wear ARM EABI v7a System Image" download it , success !

Detect change to selected date with bootstrap-datepicker

Try with below code is working for me

var date_input_field = $('input[name="date"]');
    date_input_field .datepicker({
        dateFormat: '/dd/mm/yyyy',
        container: container,
        todayHighlight: true,
        autoclose: true,
    }).on('change', function(selected){

Assign result of dynamic sql to variable

You should try this while getting SEQUENCE value in a variable from the dynamic table.

DECLARE @temp table (#temp varchar (MAX));
DECLARE @SeqID nvarchar(150);
DECLARE @Name varchar(150); 

SET @Name = (Select Name from table)
SET @SeqID = 'SELECT NEXT VALUE FOR '+ @Name + '_Sequence'
insert @temp exec (@SeqID)

SET @SeqID = (select * from @temp )


(1 row(s) affected)

Copy entire directory contents to another directory?

Neither FileUtils.copyDirectory() nor Archimedes's answer copy directory attributes (file owner, permissions, modification times, etc). provides a complete JDK7 solution that does precisely that.

Put spacing between divs in a horizontal row?

Quite a few ways to apprach this problem.

Use the box-sizing css3 property and simulate the margins with borders.

div.inside {
 width: 25%;
 border-right: 5px solid grey;
 background-color: blue;
 -moz-box-sizing:border-box; /* Firefox */
 -webkit-box-sizing:border-box; /* Safari */

<div style="width:100%; height: 200px; background-color: grey;">
 <div class="inside">A</div>
 <div class="inside">B</div>
 <div class="inside">C</div>
 <div class="inside">D</div>

Reduce the percentage of your elements widths and add some margin-right.

.outer {

.inside {

How to check Elasticsearch cluster health?


Sometimes, Localhost may not get resolved. So it tends to return an output as seen below :

# curl -XGET localhost:9200/_cluster/health?pretty

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "">
<meta http-equiv="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<title>ERROR: The requested URL could not be retrieved</title>
<style type="text/css"><!--BODY{background-color:#ffffff;font-family:verdana,sans-serif}PRE{font-family:sans-serif}--></style>
<h2>The requested URL could not be retrieved</h2>
<p>The following error was encountered while trying to retrieve the URL: <a href="http://localhost:9200/_cluster/health?">http://localhost:9200/_cluster/health?</a></p>
<p><b>Connection to failed.</b></p>

<p>The system returned: <i>(111) Connection refused</i></p>

<p>The remote host or network may be down.  Please try the request again.</p>
<p>Your cache administrator is <a href="mailto:root?subject=CacheErrorInfo%20-%20ERR_CONNECT_FAIL&amp;body=CacheHost%3A%20squid2%0D%0AErrPage%3A%20ERR_CONNECT_FAIL%0D%0AErr%3A%20(111)%20Connection%20refused%0D%0ATimeStamp%3A%20Mon,%2017%20Dec%202018%2008%3A07%3A36%20GMT%0D%0A%0D%0AClientIP%3A%20192.168.13.14%0D%0AServerIP%3A%20127.0.0.1%0D%0A%0D%0AHTTP%20Request%3A%0D%0AGET%20%2F_cluster%2Fhealth%3Fpretty%20HTTP%2F1.1%0AUser-Agent%3A%20curl%2F7.29.0%0D%0AHost%3A%20localhost%3A9200%0D%0AAccept%3A%20*%2F*%0D%0AProxy-Connection%3A%20Keep-Alive%0D%0A%0D%0A%0D%0A">root</a>.</p>

<div id="footer">Generated Mon, 17 Dec 2018 08:07:36 GMT by squid2 (squid/3.0.STABLE25)</div>

# curl -XGET localhost:9200/_cat/indices

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "">
<meta http-equiv="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<title>ERROR: The requested URL could not be retrieved</title>
<style type="text/css"><!--BODY{background-color:#ffffff;font-family:verdana,sans-serif}PRE{font-family:sans-serif}--></style>
<h2>The requested URL could not be retrieved</h2>
<p>The following error was encountered while trying to retrieve the URL: <a href="http://localhost:9200/_cat/indices">http://localhost:9200/_cat/indices</a></p>
<p><b>Connection to failed.</b></p>

<p>The system returned: <i>(111) Connection refused</i></p>

<p>The remote host or network may be down.  Please try the request again.</p>
<p>Your cache administrator is <a href="mailto:root?subject=CacheErrorInfo%20-%20ERR_CONNECT_FAIL&amp;body=CacheHost%3A%20squid2%0D%0AErrPage%3A%20ERR_CONNECT_FAIL%0D%0AErr%3A%20(111)%20Connection%20refused%0D%0ATimeStamp%3A%20Mon,%2017%20Dec%202018%2008%3A10%3A09%20GMT%0D%0A%0D%0AClientIP%3A%20192.168.13.14%0D%0AServerIP%3A%20127.0.0.1%0D%0A%0D%0AHTTP%20Request%3A%0D%0AGET%20%2F_cat%2Findices%20HTTP%2F1.1%0AUser-Agent%3A%20curl%2F7.29.0%0D%0AHost%3A%20localhost%3A9200%0D%0AAccept%3A%20*%2F*%0D%0AProxy-Connection%3A%20Keep-Alive%0D%0A%0D%0A%0D%0A">root</a>.</p>

<div id="footer">Generated Mon, 17 Dec 2018 08:10:09 GMT by squid2 (squid/3.0.STABLE25)</div>


Guess, this error is most probably returned by Local Squid deployed in the server.

So, it worked fine and good after replacing localhost by the local_ip in which the ElasticSearch has been deployed.

Getting Java version at runtime

If you can have dependency to apache utils you can use org.apache.commons.lang3.SystemUtils.

    System.out.println("Is Java version at least 1.8: " + SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_8));

Check if ADODB connection is open

This topic is old but if other people like me search a solution, this is a solution that I have found:

Public Function DBStats() As Boolean
    On Error GoTo errorHandler
        If Not IsNull(myBase.Version) Then 
            DBStats = True
        End If
        Exit Function
        DBStats = False  
End Function

So "myBase" is a Database Object, I have made a class to access to database (class with insert, update etc...) and on the module the class is use declare in an object (obviously) and I can test the connection with "[the Object].DBStats":

Dim BaseAccess As New myClass
BaseAccess.DBOpen 'I open connection
Debug.Print BaseAccess.DBStats ' I test and that tell me true
BaseAccess.DBClose ' I close the connection
Debug.Print BaseAccess.DBStats ' I test and tell me false

Edit : In DBOpen I use "OpenDatabase" and in DBClose I use ".Close" and "set myBase = nothing" Edit 2: In the function, if you are not connect, .version give you an error so if aren't connect, the errorHandler give you false

Check if a key exists inside a json object

There's several ways to do it, depending on your intent.

thisSession.hasOwnProperty('merchant_id'); will tell you if thisSession has that key itself (i.e. not something it inherits from elsewhere)

"merchant_id" in thisSession will tell you if thisSession has the key at all, regardless of where it got it.

thisSession["merchant_id"] will return false if the key does not exist, or if its value evaluates to false for any reason (e.g. if it's a literal false or the integer 0 and so on).

Does Java support default parameter values?

As Scala was mentioned, Kotlin is also worth mentioning. In Kotlin function parameters can have default values as well and they can even refer to other parameters:

fun read(b: Array<Byte>, off: Int = 0, len: Int = b.size) {

Like Scala, Kotlin runs on the JVM and can be easily integrated into existing Java projects.

What are the best practices for SQLite on Android?

  • Use a Thread or AsyncTask for long-running operations (50ms+). Test your app to see where that is. Most operations (probably) don't require a thread, because most operations (probably) only involve a few rows. Use a thread for bulk operations.
  • Share one SQLiteDatabase instance for each DB on disk between threads and implement a counting system to keep track of open connections.

Are there any best practices for these scenarios?

Share a static field between all your classes. I used to keep a singleton around for that and other things that need to be shared. A counting scheme (generally using AtomicInteger) also should be used to make sure you never close the database early or leave it open.

My solution:

The old version I wrote is available at and is not maintained. If you want to understand my solution, look at the code and read my notes. My notes are usually pretty helpful.

  1. copy/paste the code into a new file named DatabaseManager. (or download it from github)
  2. extend DatabaseManager and implement onCreate and onUpgrade like you normally would. You can create multiple subclasses of the one DatabaseManager class in order to have different databases on disk.
  3. Instantiate your subclass and call getDb() to use the SQLiteDatabase class.
  4. Call close() for each subclass you instantiated

The code to copy/paste:

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;

import java.util.concurrent.ConcurrentHashMap;

/** Extend this class and use it as an SQLiteOpenHelper class
 * DO NOT distribute, sell, or present this code as your own. 
 * for any distributing/selling, or whatever, see the info at the link below
 * Distribution, attribution, legal stuff,
 * See
 * If you ever need help with this code, contact me at [email protected] (or [email protected] )
 * Do not sell this. but use it as much as you want. There are no implied or express warranties with this code. 
 * This is a simple database manager class which makes threading/synchronization super easy.
 * Extend this class and use it like an SQLiteOpenHelper, but use it as follows:
 *  Instantiate this class once in each thread that uses the database. 
 *  Make sure to call {@link #close()} on every opened instance of this class
 *  If it is closed, then call {@link #open()} before using again.
 * Call {@link #getDb()} to get an instance of the underlying SQLiteDatabse class (which is synchronized)
 * I also implement this system (well, it's very similar) in my <a href="">Android SQLite Libray</a> at
abstract public class DatabaseManager {
    /**See SQLiteOpenHelper documentation
    abstract public void onCreate(SQLiteDatabase db);
    /**See SQLiteOpenHelper documentation
    abstract public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion);
     * *
    public void onOpen(SQLiteDatabase db){}
    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {}
    public void onConfigure(SQLiteDatabase db){}

    /** The SQLiteOpenHelper class is not actually used by your application.
    static private class DBSQLiteOpenHelper extends SQLiteOpenHelper {

        DatabaseManager databaseManager;
        private AtomicInteger counter = new AtomicInteger(0);

        public DBSQLiteOpenHelper(Context context, String name, int version, DatabaseManager databaseManager) {
            super(context, name, null, version);
            this.databaseManager = databaseManager;

        public void addConnection(){
        public void removeConnection(){
        public int getCounter() {
            return counter.get();
        public void onCreate(SQLiteDatabase db) {

        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            databaseManager.onUpgrade(db, oldVersion, newVersion);

        public void onOpen(SQLiteDatabase db) {

        public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            databaseManager.onDowngrade(db, oldVersion, newVersion);

        public void onConfigure(SQLiteDatabase db) {

    private static final ConcurrentHashMap<String,DBSQLiteOpenHelper> dbMap = new ConcurrentHashMap<String, DBSQLiteOpenHelper>();

    private static final Object lockObject = new Object();

    private DBSQLiteOpenHelper sqLiteOpenHelper;
    private SQLiteDatabase db;
    private Context context;

    /** Instantiate a new DB Helper. 
     * <br> SQLiteOpenHelpers are statically cached so they (and their internally cached SQLiteDatabases) will be reused for concurrency
     * @param context Any {@link android.content.Context} belonging to your package.
     * @param name The database name. This may be anything you like. Adding a file extension is not required and any file extension you would like to use is fine.
     * @param version the database version.
    public DatabaseManager(Context context, String name, int version) {
        String dbPath = context.getApplicationContext().getDatabasePath(name).getAbsolutePath();
        synchronized (lockObject) {
            sqLiteOpenHelper = dbMap.get(dbPath);
            if (sqLiteOpenHelper==null) {
                sqLiteOpenHelper = new DBSQLiteOpenHelper(context, name, version, this);
            //SQLiteOpenHelper class caches the SQLiteDatabase, so this will be the same SQLiteDatabase object every time
            db = sqLiteOpenHelper.getWritableDatabase();
        this.context = context.getApplicationContext();
    /**Get the writable SQLiteDatabase
    public SQLiteDatabase getDb(){
        return db;

    /** Check if the underlying SQLiteDatabase is open
     * @return whether the DB is open or not
    public boolean isOpen(){
        return (db!=null&&db.isOpen());

    /** Lowers the DB counter by 1 for any {@link DatabaseManager}s referencing the same DB on disk
     *  <br />If the new counter is 0, then the database will be closed.
     *  <br /><br />This needs to be called before application exit.
     * <br />If the counter is 0, then the underlying SQLiteDatabase is <b>null</b> until another DatabaseManager is instantiated or you call {@link #open()}
     * @return true if the underlying {@link android.database.sqlite.SQLiteDatabase} is closed (counter is 0), and false otherwise (counter > 0)
    public boolean close(){
        if (sqLiteOpenHelper.getCounter()==0){
            synchronized (lockObject){
                if (db.inTransaction())db.endTransaction();
                if (db.isOpen())db.close();
                db = null;
            return true;
        return false;
    /** Increments the internal db counter by one and opens the db if needed
    public void open(){
        if (db==null||!db.isOpen()){
                synchronized (lockObject){
                    db = sqLiteOpenHelper.getWritableDatabase();

For Loop on Lua

Your problem is simple:

names = {'John', 'Joe', 'Steve'}
for names = 1, 3 do
  print (names)

This code first declares a global variable called names. Then, you start a for loop. The for loop declares a local variable that just happens to be called names too; the fact that a variable had previously been defined with names is entirely irrelevant. Any use of names inside the for loop will refer to the local one, not the global one.

The for loop says that the inner part of the loop will be called with names = 1, then names = 2, and finally names = 3. The for loop declares a counter that counts from the first number to the last, and it will call the inner code once for each value it counts.

What you actually wanted was something like this:

names = {'John', 'Joe', 'Steve'}
for nameCount = 1, 3 do
  print (names[nameCount])

The [] syntax is how you access the members of a Lua table. Lua tables map "keys" to "values". Your array automatically creates keys of integer type, which increase. So the key associated with "Joe" in the table is 2 (Lua indices always start at 1).

Therefore, you need a for loop that counts from 1 to 3, which you get. You use the count variable to access the element from the table.

However, this has a flaw. What happens if you remove one of the elements from the list?

names = {'John', 'Joe'}
for nameCount = 1, 3 do
  print (names[nameCount])

Now, we get John Joe nil, because attempting to access values from a table that don't exist results in nil. To prevent this, we need to count from 1 to the length of the table:

names = {'John', 'Joe'}
for nameCount = 1, #names do
  print (names[nameCount])

The # is the length operator. It works on tables and strings, returning the length of either. Now, no matter how large or small names gets, this will always work.

However, there is a more convenient way to iterate through an array of items:

names = {'John', 'Joe', 'Steve'}
for i, name in ipairs(names) do
  print (name)

ipairs is a Lua standard function that iterates over a list. This style of for loop, the iterator for loop, uses this kind of iterator function. The i value is the index of the entry in the array. The name value is the value at that index. So it basically does a lot of grunt work for you.

Docker command can't connect to Docker daemon

Add the user to the docker group

  • Add the docker group if it doesn't already exist:

    sudo groupadd docker

  • Add the connected user "${USER}" to the docker group:

    sudo gpasswd -a ${USER} docker

  • Restart the Docker daemon:

    sudo service docker restart

  • Either do a newgrp docker or log out/in to activate the changes to groups.

How to create a thread?

public class ThreadParameter
            public int Port { get; set; }
            public string Path { get; set; }

Thread t = new Thread(new ParameterizedThreadStart(Startup));
t.Start(new ThreadParameter() { Port = port, Path = path});

Create an object with the port and path objects and pass it to the Startup method.

String to HtmlDocument

you could get a htmldocument by:

 System.Net.WebClient wc = new System.Net.WebClient();

 System.IO.Stream stream = wc.OpenRead(url);
 System.IO.StreamReader reader = new System.IO.StreamReader(stream);
 string s = reader.ReadToEnd();

 HtmlDocument doc = new HtmlDocument();

so you have getbiyid and getbyname ... but any further you'd better of with
HTML Agility Pack as suggested . f.e you can do: doc.DocumentNode.SelectNodes(xpathselector) or regex to parse the doc ..

btw: why not regex ? . its soo cool if you can use it right... but xpath is also very mighty ... so "choose your poison"


Spark SQL: apply aggregate functions to a list of columns

Current answers are perfectly correct on how to create the aggregations, but none actually address the column alias/renaming that is also requested in the question.

Typically, this is how I handle this case:

val dimensionFields = List("col1")
val metrics = List("col2", "col3", "col4")
val columnOfInterests = dimensions ++ metrics

val df ="some_table"). 
    .select( => col(c)):_*)
    .groupBy( => col(d)): _*)
    .agg( m => m -> "sum").toMap)
    .toDF(columnOfInterests:_*)    // that's the interesting part

The last line essentially renames every columns of the aggregated dataframe to the original fields, essentially changing sum(col2) and sum(col3) to simply col2 and col3.

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

10 years later, you have an alternative to tar, illustrated with Git 2.30 (Q1 2021), which uses "git archive"(man) to produce the release tarball instead of tar.
(You don't need Git 2.30 to apply that alternative)

See commit 4813277 (11 Oct 2020), and commit 93e7031 (10 Oct 2020) by René Scharfe (rscharfe).
(Merged by Junio C Hamano -- gitster -- in commit 63e5273, 27 Oct 2020)

Makefile: use git init/add/commit/archive for dist-doc

Signed-off-by: René Scharfe

Reduce the dependency on external tools by generating the distribution archives for HTML documentation and manpages using git(man) commands instead of tar. This gives the archive entries the same meta data as those in the dist archive for binaries.

So instead of:

tar cf ../archive.tar .

You can do using Git only:

git -C workspace init
git -C workspace add .
git -C workspace commit -m workspace
git -C workspace archive --format=tar --prefix=./ HEAD^{tree} > workspace.tar
rm -Rf workspace/.git

That was initially proposed because, as explained here, some exotic platform might have an old tar distribution with lacking options.

A 'for' loop to iterate over an enum in Java

values() method may simply work:

for (Direction  d : Direction.values()) {
   //whatever you want to do with each of these enum values  

Save child objects automatically using JPA Hibernate

in your setChilds, you might want to try looping thru the list and doing something like

child.parent = this;

you also should set up the cascade on the parent to the appropriate values.

How do I remove a MySQL database?

For Visual Studio, in the package manager console:


How to find sum of several integers input by user using do/while, While statement or For statement

You should do:

using namespace std;
int main ()

    int sum = 0;
    int number;
    int numberitems;

    cout << "Enter number of items: \n";
    cin >> numberitems;

    for(int i=0;i<numberitems;i++)
        cout << "Enter number <<i<<":" \n";
        cin >> number; sum+=number;
    cout<<"sum is: "<< sum<<endl;

And with a while statement

#include <iostream>
using namespace std;
int main ()
    int sum = 0;
    int number;
    int numberitems;

    cout << "Enter number: \n";

    while (count <=numberitems)
        cin >> number;
    cout << sum << endl;

How can I do factory reset using adb in android?

I have made it from fastboot mode (Phone - Xiomi Mi5 Android 6.0.1)

Here is steps:

# check if device available
fastboot devices
# remove user data
fastboot erase userdata
# remove cache
fastboot erase cache 
# reboot device
fastboot reboot

Checking if a variable is an integer in PHP

Using is_numeric() for checking if a variable is an integer is a bad idea. This function will return TRUE for 3.14 for example. It's not the expected behavior.

To do this correctly, you can use one of these options:

Considering this variables array :

$variables = [
    "TEST 0" => 0,
    "TEST 1" => 42,
    "TEST 2" => 4.2,
    "TEST 3" => .42,
    "TEST 4" => 42.,
    "TEST 5" => "42",
    "TEST 6" => "a42",
    "TEST 7" => "42a",
    "TEST 8" => 0x24,
    "TEST 9" => 1337e0

The first option (FILTER_VALIDATE_INT way) :

# Check if your variable is an integer
if ( filter_var($variable, FILTER_VALIDATE_INT) === false ) {
  echo "Your variable is not an integer";

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

The second option (CASTING COMPARISON way) :

# Check if your variable is an integer
if ( strval($variable) !== strval(intval($variable)) ) {
  echo "Your variable is not an integer";

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

The third option (CTYPE_DIGIT way) :

# Check if your variable is an integer
if ( ! ctype_digit(strval($variable)) ) {
  echo "Your variable is not an integer";

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

The fourth option (REGEX way) :

# Check if your variable is an integer
if ( ! preg_match('/^\d+$/', $variable) ) {
  echo "Your variable is not an integer";

Output :

TEST 0 : 0 (type:integer) is an integer ?
TEST 1 : 42 (type:integer) is an integer ?
TEST 2 : 4.2 (type:double) is not an integer ?
TEST 3 : 0.42 (type:double) is not an integer ?
TEST 4 : 42 (type:double) is an integer ?
TEST 5 : 42 (type:string) is an integer ?
TEST 6 : a42 (type:string) is not an integer ?
TEST 7 : 42a (type:string) is not an integer ?
TEST 8 : 36 (type:integer) is an integer ?
TEST 9 : 1337 (type:double) is an integer ?

How to increase memory limit for PHP over 2GB?

Have you tried using the value in MB ?

php_value memory_limit 2048M

Also try editing this value in php.ini not Apache.

Stopping an Android app from console

Edit: Long after I wrote this post and it was accepted as the answer, the am force-stop command was implemented by the Android team, as mentioned in this answer.

Alternatively: Rather than just stopping the app, since you mention wanting a "clean slate" for each test run, you can use adb shell pm clear, which will stop the app process and clear out all the stored data for that app.

If you're on Linux:
adb shell ps | grep com.myapp | awk '{print $2}' | xargs adb shell kill

That will only work for devices/emulators where you have root immediately upon running a shell. That can probably be refined slightly to call su beforehand.

Otherwise, you can do (manually, or I suppose scripted):
pc $ adb -d shell
android $ su
android # ps
android # kill <process id from ps output>

How does true/false work in PHP?

Zero is false, nonzero is true.

In php you can test more explicitly using the === operator.

if (0==false) 
    echo "works"; // will echo works

if (0===false) 
    echo "works"; // will not echo anything

How do I create an executable in Visual Studio 2013 w/ C++?

Do ctrl+F5 to compile and run your project without debugging. Look at the output pane (defaults to "Show output from Build"). If it compiled successfully, the path to the .exe file should be there after {projectname}.vcxproj ->

How to loop through array in jQuery?

Try this:

$.grep(array, function(element) {


Redirect with CodeIgniter

If your directory structure is like this,


And when you are going to redirect it in same controller in which you are working then just write the following code.

    if ($some_value === FALSE/TRUE) //You may give 0/1 as well,its up to your logic
         redirect('same_controller/method', 'refresh');

And if you want to redirect to another control then use the following code.

if ($some_value === FALSE/TRUE) //You may give 0/1 as well,its up to your logic
     redirect('folder_name/any_controller_name/method', 'refresh');

Is it possible to install both 32bit and 64bit Java on Windows 7?

You can install multiple Java runtimes under Windows (including Windows 7) as long as each is in their own directory.

For example, if you are running Win 7 64-bit, or Win Server 2008 R2, you may install 32-bit JRE in "C:\Program Files (x86)\Java\jre6" and 64-bit JRE in "C:\Program Files\Java\jre6", and perhaps IBM Java 6 in "C:\Program Files (x86)\IBM\Java60\jre".

The Java Control Panel app theoretically has the ability to manage multiple runtimes: Java tab >> View... button

There are tabs for User and System settings. You can add additional runtimes with Add or Find, but once you have finished adding runtimes and hit OK, you have to hit Apply in the main Java tab frame, which is not as obvious as it could be - otherwise your changes will be lost.

If you have multiple versions installed, only the main version will auto-update. I have not found a solution to this apart from the weak workaround of manually updating whenever I see an auto-update, so I'd love to know if anyone has a fix for that.

Most Java IDEs allow you to select any Java runtime on your machine to build against, but if not using an IDE, you can easily manage this using environment variables in a cmd window. Your PATH and the JAVA_HOME variable determine which runtime is used by tools run from the shell. Set the JAVA_HOME to the jre directory you want and put the bin directory into your path (and remove references to other runtimes) - with IBM you may need to add multiple bin directories. This is pretty much all the set up that the default system Java does. You can also set CLASSPATH, ANT_HOME, MAVEN_HOME, etc. to unique values to match your runtime.

CSS centred header image

I think this is what you need if I'm understanding you correctly:

<div id="wrapperHeader">
 <div id="header">
  <img src="images/logo.png" alt="logo" />

div#wrapperHeader {
 height;200px; /* height of the background image? */
 background:url(images/header.png) repeat-x 0 0;

div#wrapperHeader div#header {
 margin:0 auto;

div#wrapperHeader div#header img {
 width:; /* the width of the logo image */
 height:; /* the height of the logo image */
 margin:0 auto;

how to read value from string.xml in android?


  • Android Studio 3.1.4
  • Kotlin version: 1.2.60


  • single line use
  • minimum code
  • use suggestions from the compiler

Step 1. Application()

Get link to the context of you application

class MY_APPLICATION_NAME: Application() {

    companion object {
        private lateinit var instance: MY_APPLICATION_NAME

        fun getAppContext(): Context = instance.applicationContext

    override fun onCreate() {
        instance = this


Step 2. Add int extension

inline fun Int.toLocalizedString(): String = MY_APPLICATION_NAME.getAppContext().resources.getString(this)



    <!-- .......  -->
    <string name="no_internet_connection">No internet connection</string>
    <!-- .......  -->

Get string value:

val errorMessage = R.string.no_internet_connection.toLocalizedString()


enter image description here enter image description here

How to make an input type=button act like a hyperlink and redirect using a get request?

I think that is your need.

a href="#" onclick="document.forms[0].submit();return false;"

Simulating a click in jQuery/JavaScript on a link

Try this

function submitRequest(buttonId) {
    if (document.getElementById(buttonId) == null
            || document.getElementById(buttonId) == undefined) {
    if (document.getElementById(buttonId).dispatchEvent) {
        var e = document.createEvent("MouseEvents");
        e.initEvent("click", true, true);
    } else {

and you can use it like


How to set index.html as root file in Nginx?

in your location block you can do:

location / {
  try_files $uri $uri/index.html;

which will tell ngingx to look for a file with the exact name given first, and if none such file is found it will try uri/index.html. So if a request for comes it it would look for an exact file match first, and not finding that would then check for index.html

Format LocalDateTime with Timezone in Java8

LocalDateTime is a date-time without a time-zone. You specified the time zone offset format symbol in the format, however, LocalDateTime doesn't have such information. That's why the error occured.

If you want time-zone information, you should use ZonedDateTime.

DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyyMMdd HH:mm:ss.SSSSSS Z");;
=> "20140829 14:12:22.122000 +09"

How to get current PHP page name

In your case you can use __FILE__ variable !
It should help.
It is one of predefined.
Read more about predefined constants in PHP

How can I display just a portion of an image in HTML/CSS?

As mentioned in the question, there is the clip css property, although it does require that the element being clipped is position: absolute; (which is a shame):

.container {_x000D_
  position: relative;_x000D_
#clip {_x000D_
  position: absolute;_x000D_
  clip: rect(0, 100px, 200px, 0);_x000D_
  /* clip: shape(top, right, bottom, left); NB 'rect' is the only available option */_x000D_
<div class="container">_x000D_
  <img src="" />_x000D_
<div class="container">_x000D_
  <img id="clip" src="" />_x000D_

JS Fiddle demo, for experimentation.

To supplement the original answer – somewhat belatedly – I'm editing to show the use of clip-path, which has replaced the now-deprecated clip property.

The clip-path property allows a range of options (more-so than the original clip), of:

  • inset — rectangular/cuboid shapes, defined with four values as 'distance-from' (top right bottom left).
  • circlecircle(diameter at x-coordinate y-coordinate).
  • ellipseellipse(x-axis-length y-axis-length at x-coordinate y-coordinate).
  • polygon — defined by a series of x/y coordinates in relation to the element's origin of the top-left corner. As the path is closed automatically the realistic minimum number of points for a polygon should be three, any fewer (two) is a line or (one) is a point: polygon(x-coordinate1 y-coordinate1, x-coordinate2 y-coordinate2, x-coordinate3 y-coordinate3, [etc...]).
  • url — this can be either a local URL (using a CSS id-selector) or the URL of an external file (using a file-path) to identify an SVG, though I've not experimented with either (as yet), so I can offer no insight as to their benefit or caveat.

div.container {_x000D_
  display: inline-block;_x000D_
#rectangular {_x000D_
  -webkit-clip-path: inset(30px 10px 30px 10px);_x000D_
  clip-path: inset(30px 10px 30px 10px);_x000D_
#circle {_x000D_
  -webkit-clip-path: circle(75px at 50% 50%);_x000D_
  clip-path: circle(75px at 50% 50%)_x000D_
#ellipse {_x000D_
  -webkit-clip-path: ellipse(75px 50px at 50% 50%);_x000D_
  clip-path: ellipse(75px 50px at 50% 50%);_x000D_
#polygon {_x000D_
  -webkit-clip-path: polygon(50% 0, 100% 38%, 81% 100%, 19% 100%, 0 38%);_x000D_
  clip-path: polygon(50% 0, 100% 38%, 81% 100%, 19% 100%, 0 38%);_x000D_
<div class="container">_x000D_
  <img id="control" src="" />_x000D_
<div class="container">_x000D_
  <img id="rectangular" src="" />_x000D_
<div class="container">_x000D_
  <img id="circle" src="" />_x000D_
<div class="container">_x000D_
  <img id="ellipse" src="" />_x000D_
<div class="container">_x000D_
  <img id="polygon" src="" />_x000D_

JS Fiddle demo, for experimentation.


Rebuild or regenerate 'ic_launcher.png' from images in Android Studio

the answers above were confusing to me. Here is what i did:

  • File ->new Image Asset
  • the first field "Asset type" must be launcher icons. browse to the file you want as icon, select it and android studio will show you in the same window what it will look like under different resolutions.

  • choose a different name for it, click next. Now the icon set for all those hdpi, xhdpi, mdpi will be in corresponding mipmap folders

  • finally, most importantly go to your manifest file and change "android:icon" to the name of your new icon image.

Laravel check if collection is empty

You can always count the collection. For example $mentor->intern->count() will return how many intern does a mentor have.

In your code you can do something like this

foreach($mentors as $mentor)
    @if($mentor->intern->count() > 0)
    @foreach($mentor->intern as $intern)
        <tr class="table-row-link" data-href="/werknemer/{!! $intern->employee->EmployeeId !!}">
            <td>{{ $intern->employee->FirstName }}</td>
            <td>{{  $intern->employee->LastName }}</td>
        Mentor don't have any intern

View's SELECT contains a subquery in the FROM clause

As the more recent MySQL documentation on view restrictions says:

Before MySQL 5.7.7, subqueries cannot be used in the FROM clause of a view.

This means, that choosing a MySQL v5.7.7 or newer or upgrading the existing MySQL instance to such a version, would remove this restriction on views completely.

However, if you have a current production MySQL version that is earlier than v5.7.7, then the removal of this restriction on views should only be one of the criteria being assessed while making a decision as to upgrade or not. Using the workaround techniques described in the other answers may be a more viable solution - at least on the shorter run.

Trying to get Laravel 5 email to work

None of the above solutions worked for me on localhost. I even allowed access from less secure apps, allowed access through display unlock captcha and set the verify peer and verify peer name to false for SSL.

Eventually, I used the open source SMTP testing solution of MailHog. The steps are as follows:

  1. Download the latest version of MailHog for your OS
  2. Specify the following settings in your .env file







[email protected]

  1. Run the downloaded file of MailHog
  2. Send Email
  3. Check sent email by going to localhost:8025

Why and how to fix? IIS Express "The specified port is in use"

To Solve this issue follow the below step:

  1. Open the CMD run as Administrator mode
  2. Then execute the command netsh http add iplisten ipaddress=::

  3. After run the project

JavaScript URL Decode function

Use this


I'm not a great JS programmer, tried all, and this worked awesome!

Elegant way to create empty pandas DataFrame with NaN of type float

For multiple columns you can do:

df = pd.DataFrame(np.zeros([nrow, ncol])*np.nan)

is there something like isset of php in javascript/jQuery?

You can just:

    //Yes it is set
    //do something
else {
    //No it is not set
    //Or its null
    //do something else 

Openstreetmap: embedding map in webpage (like Google Maps)

There is simple way to do it if you fear Javascript...I'm still learning. Open Street makes a simple Wordpress plugin you can customize. Add OSM Widget plugin.

This will be a filler until I figure out my Python Java concotion using coverter TIGER line files from the Census Bureau.

Apply CSS rules to a nested class inside a div

Use Css Selector for this, or learn more about Css Selector just go here

#main_text > .title {
  /* Style goes here */

#main_text .title {
  /* Style goes here */

Calling other function in the same controller?

To call a function inside a same controller in any laravel version follow as bellow

$role = $this->sendRequest('parameter');
// sendRequest is a public function

What is the difference between XML and XSD?

Basically an XSD file defines how the XML file is going to look like. It's a Schema file which defines the structure of the XML file. So it specifies what the possible fields are and what size they are going to be.

An XML file is an instance of XSD as it uses the rules defined in the XSD.

Calculate mean across dimension in a 2D array

Here is a non-numpy solution:

>>> a = [[40, 10], [50, 11]]
>>> [float(sum(l))/len(l) for l in zip(*a)]
[45.0, 10.5]

How do I set the default value for an optional argument in Javascript?

You can also do this with ArgueJS:

function (){
  arguments = __({nodebox: undefined, str: [String: "hai"]})

  // and now on, you can access your arguments by
  //   arguments.nodebox and arguments.str

Difference between return 1, return 0, return -1 and exit?

To indicate execution status.

status 0 means the program succeeded.

status different from 0 means the program exited due to error or anomaly.

return n; from your main entry function will terminate your process and report to the parent process (the one that executed your process) the result of your process. 0 means SUCCESS. Other codes usually indicates a failure and its meaning.

Why I can't access remote Jupyter Notebook server?

edit the following on jupyter_notebook_config file
enter actual computer IP address
c.NotebookApp.ip = '192.168.x.x'
c.NotebookApp.allow_origin = '*'

on the client side launch jupyter notebook with login password
jupyter notebook password

after setting password login on browser and then type the remote server ip address followed by the port. example

Inserting code in this LaTeX document with indentation

Minted, whether from GitHub or CTAN, the Comprehensive TeX Archive Network, works in Overleaf, TeX Live and MiKTeX.

It requires the installation of the Python package Pygments; this is explained in the documentation in either source above. Although Pygments brands itself as a Python syntax highlighter, Minted guarantees the coverage of hundreds of other languages.



\begin{minted}[mathescape, linenos]{python}

# Note: $\pi=\lim_{n\to\infty}\frac{P_n}{d}$
title = "Hello World"

sum = 0
for i in range(10):
 sum += i




enter image description here

SQL Server : fetching records between two dates?

Your question didnt ask how to use BETWEEN correctly, rather asked for help with the unexpectedly truncated results...

As mentioned/hinting at in the other answers, the problem is that you have time segments in addition to the dates.

In my experience, using date diff is worth the extra wear/tear on the keyboard. It allows you to express exactly what you want, and you are covered.

select * 
from xxx 
where datediff(d, '2012-10-26', dates) >=0
and  datediff(d, dates,'2012-10-27') >=0

using datediff, if the first date is before the second date, you get a positive number. There are several ways to write the above, for instance always having the field first, then the constant. Just flipping the operator. Its a matter of personal preference.

you can be explicit about whether you want to be inclusive or exclusive of the endpoints by dropping one or both equal signs.

BETWEEN will work in your case, because the endpoints are both assumed to be midnight (ie DATEs). If your endpoints were also DATETIME, using BETWEEN may require even more casting. In my mind DATEDIFF was put in our lives to insulate us from those issues.

how to read a long multiline string line by line in python

by splitting with newlines.

for line in wallop_of_a_string_with_many_lines.split('\n'):

if you iterate over a string, you are iterating char by char in that string, not by line.

>>>string = 'abc'
>>>for line in string:
    print line


Leave menu bar fixed on top when scrolled

Or do this in more dynamic way

$(window).bind('scroll', function () {
    var menu = $('.menu');
    if ($(window).scrollTop() > menu.offset().top) {
    } else {

In CSS add class

.fixed {
    position: fixed;
    top: 0;

repaint() in Java

You may need to call frame.repaint() as well to force the frame to actually redraw itself. I've had issues before where I tried to repaint a component and it wasn't updating what was displayed until the parent's repaint() method was called.

Java naming convention for static final variables

These variables are constants, i.e. private static final whether they're named in all caps or not. The all-caps convention simply makes it more obvious that these variables are meant to be constants, but it isn't required. I've seen

private static final Logger log = Logger.getLogger(MyClass.class);

in lowercase before, and I'm fine with it because I know to only use the logger to log messages, but it does violate the convention. You could argue that naming it log is a sub-convention, I suppose. But in general, naming constants in uppercase isn't the One Right Way, but it is The Best Way.

Failed to Connect to MySQL at localhost:3306 with user root

MySQL default port is 3306 but it may be unavailable for some reasons, try to restart your machine. Also sesrch for your MySQL configuration file (should be called "my.cnf") and check if the used port is 3306 or 3307, if is 3307 you can change it to 3306 and then reboot your MySQL server.

batch file to copy files to another location?

Open Notepad.

Type the following lines into it (obviously replace the folders with your ones)

@echo off
rem you could also remove the line above, because it might help you to see what happens

rem /i option is needed to avoid the batch file asking you whether destination folder is a file or a folder
rem /e option is needed to copy also all folders and subfolders
xcopy "c:\New Folder" "c:\Copy of New Folder" /i /e

Save the file as backup.bat (not .txt)

Double click on the file to run it. It will backup the folder and all its contents files/subfolders.

Now if you want the batch file to be run everytime you login in Windows, you should place it in Windows Startup menu. You find it under: Start > All Program > Startup To place the batch file in there either drag it into the Startup menu or RIGH click on the Windows START button and select Explore, go in Programs > Startup, and copy the batch file into there.

To run the batch file everytime the folder is updated you need an application, it can not be done with just a batch file.

How do I use SELECT GROUP BY in DataTable.Select(Expression)?

    .GroupBy(r => new { Col1 = r["Col1"], Col2 = r["Col2"] })
    .Select(g =>
        var row = dt.NewRow();

        row["PK"] = g.Min(r => r.Field<int>("PK"));
        row["Col1"] = g.Key.Col1;
        row["Col2"] = g.Key.Col2;

        return row;


Checking images for similarity with OpenCV

Sam's solution should be sufficient. I've used combination of both histogram difference and template matching because not one method was working for me 100% of the times. I've given less importance to histogram method though. Here's how I've implemented in simple python script.

import cv2

class CompareImage(object):

    def __init__(self, image_1_path, image_2_path):
        self.minimum_commutative_image_diff = 1
        self.image_1_path = image_1_path
        self.image_2_path = image_2_path

    def compare_image(self):
        image_1 = cv2.imread(self.image_1_path, 0)
        image_2 = cv2.imread(self.image_2_path, 0)
        commutative_image_diff = self.get_image_difference(image_1, image_2)

        if commutative_image_diff < self.minimum_commutative_image_diff:
            print "Matched"
            return commutative_image_diff
        return 10000 //random failure value

    def get_image_difference(image_1, image_2):
        first_image_hist = cv2.calcHist([image_1], [0], None, [256], [0, 256])
        second_image_hist = cv2.calcHist([image_2], [0], None, [256], [0, 256])

        img_hist_diff = cv2.compareHist(first_image_hist, second_image_hist, cv2.HISTCMP_BHATTACHARYYA)
        img_template_probability_match = cv2.matchTemplate(first_image_hist, second_image_hist, cv2.TM_CCOEFF_NORMED)[0][0]
        img_template_diff = 1 - img_template_probability_match

        # taking only 10% of histogram diff, since it's less accurate than template method
        commutative_image_diff = (img_hist_diff / 10) + img_template_diff
        return commutative_image_diff

    if __name__ == '__main__':
        compare_image = CompareImage('image1/path', 'image2/path')
        image_difference = compare_image.compare_image()
        print image_difference

Using tr to replace newline with space

Best guess is you are on windows and your line ending settings are set for windows. See this topic: How to change line-ending settings

or use:

tr '\r\n' ' '

How to send email from MySQL 5.1

If you have an SMTP service running, you can outfile to the drop directory. If you have high volume, you may result with duplicate file names, but there are ways to avoid that.

Otherwise, you will need to create a UDF.

Here's a sample trigger solution:

CREATE TRIGGER test.autosendfromdrop BEFORE INSERT ON test.emaildrop
      SELECT  concat("To: ",NEW.To),
              concat("From: ",NEW.From),
              concat("Subject: ",NEW.Subject),
          INTO OUTFILE 
              FIELDS TERMINATED by '\r\n' ESCAPED BY '';            

To markup the message body you will need something like this...

CREATE FUNCTION `HTMLBody`(Msg varchar(8192)) 
    RETURNS varchar(17408) CHARSET latin1 DETERMINISTIC
  declare tmpMsg varchar(17408);
  set tmpMsg = cast(concat(
      'Date: ',date_format(NOW(),'%e %b %Y %H:%i:%S -0600'),'\r\n',
      'MIME-Version: 1.0','\r\n',
      'Content-Type: multipart/alternative;','\r\n',
      ' boundary=\"----=_NextPart_000_0000_01CA4B3F.8C263EE0\"','\r\n',
      'Content-Class: urn:content-classes:message','\r\n',
      'Importance: normal','\r\n',
      'Priority: normal','\r\n','','\r\n','','\r\n',
      'This is a multi-part message in MIME format.','\r\n','','\r\n',
      'Content-Type: text/plain;','\r\n',
      '  charset=\"iso-8859-1\"','\r\n',
      'Content-Transfer-Encoding: 7bit','\r\n','','\r\n','','\r\n',
      'Content-Type: text/html','\r\n',
      'Content-Transfer-Encoding: 7bit','\r\n','','\r\n',
      ) as char);
  RETURN tmpMsg;

changing iframe source with jquery

Using attr() pointing to an external domain may trigger an error like this in Chrome: "Refused to display document because display forbidden by X-Frame-Options". The workaround to this can be to move the whole iframe HTML code into the script (eg. using .html() in jQuery).


var divMapLoaded = false;
$("#container").scroll(function() {
    if ((!divMapLoaded) && ($("#map").position().left <= $("#map").width())) {
    $("#map-iframe").html("<iframe id=\"map-iframe\" " +
        "width=\"100%\" height=\"100%\" frameborder=\"0\" scrolling=\"no\" " +
        "marginheight=\"0\" marginwidth=\"0\" " +
        "src=\";cid=0x3e589d98063177ab&amp;ie=UTF8&amp;iwloc=A&amp;brcurrent=5,0,1&amp;ll=41.123115,16.853177&amp;spn=0.005617,0.009943&amp;output=embed\"" +
    divMapLoaded = true;

Difference between core and processor

Let's clarify first what is a CPU and what is a core, a central processing unit CPU, can have multiple core units, those cores are a processor by itself, capable of execute a program but it is self contained on the same chip.

In the past one CPU was distributed among quite a few chips, but as Moore's Law progressed they made to have a complete CPU inside one chip (die), since the 90's the manufacturer's started to fit more cores in the same die, so that's the concept of Multi-core.

In these days is possible to have hundreds of cores on the same CPU (chip or die) GPUs, Intel Xeon. Other technique developed in the 90's was simultaneous multi-threading, basically they found that was possible to have another thread in the same single core CPU, since most of the resources were duplicated already like ALU, multiple registers.

So basically a CPU can have multiple cores each of them capable to run one thread or more at the same time, we may expect to have more cores in the future, but with more difficulty to be able to program efficiently.

EPPlus - Read Excel Table

There is no native but what if you use what I put in this post:

How to parse excel rows back to types using EPPlus

If you want to point it at a table only it will need to be modified. Something like this should do it:

public static IEnumerable<T> ConvertTableToObjects<T>(this ExcelTable table) where T : new()
    //DateTime Conversion
    var convertDateTime = new Func<double, DateTime>(excelDate =>
        if (excelDate < 1)
            throw new ArgumentException("Excel dates cannot be smaller than 0.");

        var dateOfReference = new DateTime(1900, 1, 1);

        if (excelDate > 60d)
            excelDate = excelDate - 2;
            excelDate = excelDate - 1;
        return dateOfReference.AddDays(excelDate);

    //Get the properties of T
    var tprops = (new T())

    //Get the cells based on the table address
    var start = table.Address.Start;
    var end = table.Address.End;
    var cells = new List<ExcelRangeBase>();

    //Have to use for loops insteadof worksheet.Cells to protect against empties
    for (var r = start.Row; r <= end.Row; r++)
        for (var c = start.Column; c <= end.Column; c++)
            cells.Add(table.WorkSheet.Cells[r, c]);

    var groups = cells
        .GroupBy(cell => cell.Start.Row)

    //Assume the second row represents column data types (big assumption!)
    var types = groups
        .Select(rcell => rcell.Value.GetType())

    //Assume first row has the column names
    var colnames = groups
        .Select((hcell, idx) => new { Name = hcell.Value.ToString(), index = idx })
        .Where(o => tprops.Select(p => p.Name).Contains(o.Name))

    //Everything after the header is data
    var rowvalues = groups
        .Skip(1) //Exclude header
        .Select(cg => cg.Select(c => c.Value).ToList());

    //Create the collection container
    var collection = rowvalues
        .Select(row =>
            var tnew = new T();
            colnames.ForEach(colname =>
                //This is the real wrinkle to using reflection - Excel stores all numbers as double including int
                var val = row[colname.index];
                var type = types[colname.index];
                var prop = tprops.First(p => p.Name == colname.Name);

                //If it is numeric it is a double since that is how excel stores all numbers
                if (type == typeof(double))
                    if (!string.IsNullOrWhiteSpace(val?.ToString()))
                        //Unbox it
                        var unboxedVal = (double)val;

                        //FAR FROM A COMPLETE LIST!!!
                        if (prop.PropertyType == typeof(Int32))
                            prop.SetValue(tnew, (int)unboxedVal);
                        else if (prop.PropertyType == typeof(double))
                            prop.SetValue(tnew, unboxedVal);
                        else if (prop.PropertyType == typeof(DateTime))
                            prop.SetValue(tnew, convertDateTime(unboxedVal));
                            throw new NotImplementedException(String.Format("Type '{0}' not implemented yet!", prop.PropertyType.Name));
                    //Its a string
                    prop.SetValue(tnew, val);

            return tnew;

    //Send it back
    return collection;

Here is a test method:

public void Table_To_Object_Test()
    //Create a test file
    var fi = new FileInfo(@"c:\temp\Table_To_Object.xlsx");

    using (var package = new ExcelPackage(fi))
        var workbook = package.Workbook;
        var worksheet = workbook.Worksheets.First();
        var ThatList = worksheet.Tables.First().ConvertTableToObjects<ExcelData>();
        foreach (var data in ThatList)
            Console.WriteLine(data.Id + data.Name + data.Gender);


Gave this in the console:


Just be careful if you Id field is an number or string in excel since the class is expecting a string.

AngularJS - How to use $routeParams in generating the templateUrl?


.when('/enquiry/:page', {
    template: '<div ng-include src="templateUrl" onload="onLoad()"></div>',
    controller: 'enquiryCtrl'


// template onload event
$scope.onLoad = function() {
    f_tcalInit();  // or other onload stuff

// initialize
$scope.templateUrl = 'ci_index.php/adminctrl/enquiry/'+$;

I believe it is a weakness in angularjs that $routeParams is NOT visible inside the router. A tiny enhancement would make a world of difference during implementation.

org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1

For update() and saveOrUpdate() methods, id generator value should be there in the database. For the save() method, id generator is not required.

Best way to generate xml?

I would use the yattag library. I think it's the most pythonic way:

from yattag import Doc

doc, tag, text = Doc().tagtext()

with tag('food'):
    with tag('name'):
        text('French Breakfast')
    with tag('price', currency='USD'):
    with tag('ingredients'):
        for ingredient in ('baguettes', 'jam', 'butter', 'croissants'):
            with tag('ingredient'):


Simulate delayed and dropped packets on Linux

For dropped packets I would simply use iptables and the statistic module.

iptables -A INPUT -m statistic --mode random --probability 0.01 -j DROP

Above will drop an incoming packet with a 1% probability. Be careful, anything above about 0.14 and most of you tcp connections will most likely stall completely.

Take a look at man iptables and search for "statistic" for more information.