Programs & Examples On #Custom compare

How to create a new object instance from a Type

I can across this question because I was looking to implement a simple CloneObject method for arbitrary class (with a default constructor)

With generic method you can require that the type implements New().

Public Function CloneObject(Of T As New)(ByVal src As T) As T
    Dim result As T = Nothing
    Dim cloneable = TryCast(src, ICloneable)
    If cloneable IsNot Nothing Then
        result = cloneable.Clone()
    Else
        result = New T
        CopySimpleProperties(src, result, Nothing, "clone")
    End If
    Return result
End Function

With non-generic assume the type has a default constructor and catch an exception if it doesn't.

Public Function CloneObject(ByVal src As Object) As Object
    Dim result As Object = Nothing
    Dim cloneable As ICloneable
    Try
        cloneable = TryCast(src, ICloneable)
        If cloneable IsNot Nothing Then
            result = cloneable.Clone()
        Else
            result = Activator.CreateInstance(src.GetType())
            CopySimpleProperties(src, result, Nothing, "clone")
        End If
    Catch ex As Exception
        Trace.WriteLine("!!! CloneObject(): " & ex.Message)
    End Try
    Return result
End Function

How to find if element with specific id exists or not

document.getElementById('yourId')

is the correct way.

the document refers the HTML document that is loaded in the DOM.

and it searches the id using the function getElementById() which takes a parameter of the id of an element

Solution will be :

var elem = (document.getElementById('myElement'))? document.getElementById('myElement').value : '';

/* this will assign a value or give you and empty string */

How to get a resource id with a known resource name?

int resourceID = 
    this.getResources().getIdentifier("resource name", "resource type as mentioned in R.java",this.getPackageName());

Send JavaScript variable to PHP variable

PHP runs on the server and Javascript runs on the client, so you can't set a PHP variable to equal a Javascript variable without sending the value to the server. You can, however, set a Javascript variable to equal a PHP variable:

<script type="text/javascript">
  var foo = '<?php echo $foo ?>';
</script>

To send a Javascript value to PHP you'd need to use AJAX. With jQuery, it would look something like this (most basic example possible):

var variableToSend = 'foo';
$.post('file.php', {variable: variableToSend});

On your server, you would need to receive the variable sent in the post:

$variable = $_POST['variable'];

Group by with multiple columns using lambda

Further to aduchis answer above - if you then need to filter based on those group by keys, you can define a class to wrap the many keys.

return customers.GroupBy(a => new CustomerGroupingKey(a.Country, a.Gender))
                .Where(a => a.Key.Country == "Ireland" && a.Key.Gender == "M")
                .SelectMany(a => a)
                .ToList();

Where CustomerGroupingKey takes the group keys:

    private class CustomerGroupingKey
    {
        public CustomerGroupingKey(string country, string gender)
        {
            Country = country;
            Gender = gender;
        }

        public string Country { get; }

        public string Gender { get; }
    }

regular expression to validate datetime format (MM/DD/YYYY)

based on this

dd-mm-yy

I modified the original to this:

^(?:(?:(?:0?[13578]|1[02]|(?:Jan|Mar|May|Jul|Aug|Oct|Dec))(\/|-|\.)31)\1|(?:(?:0?[1,3-9]|1[0-2]|(?:Jan|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec))(\/|-|\.)(?:29|30)\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:(?:0?2|(?:Feb))(\/|-|\.)(?:29)\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:(?:0?[1-9]|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep))|(?:1[0-2]|(?:Oct|Nov|Dec)))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])\4(?:(?:1[6-9]|[2-9]\d)?\d{2})$

test the regex here

else & elif statements not working in Python

Besides that your indention is wrong. The code wont work. I know you are using python 3. something. I am using python 2.7.3 the code that will actually work for what you trying accomplish is this.

number = str(23)
guess =  input('Enter a number: ')
if guess == number:
   print('Congratulations! You guessed it.')
elif guess < number:
     print('Wrong Number')
elif guess < number:
     print("Wrong Number')

The only difference I would tell python that number is a string of character for the code to work. If not is going to think is a Integer. When somebody runs the code they are inputing a string not an integer. There are many ways of changing this code but this is the easy solution I wanted to provide there is another way that I cant think of without making the 23 into a string. Or you could of "23" put quotations or you could of use int() function in the input. that would transform anything they input into and integer a number.

How do I find the location of Python module sources?

Running python -v from the command line should tell you what is being imported and from where. This works for me on Windows and Mac OS X.

C:\>python -v
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# C:\Python24\lib\site.pyc has bad mtime
import site # from C:\Python24\lib\site.py
# wrote C:\Python24\lib\site.pyc
# C:\Python24\lib\os.pyc has bad mtime
import os # from C:\Python24\lib\os.py
# wrote C:\Python24\lib\os.pyc
import nt # builtin
# C:\Python24\lib\ntpath.pyc has bad mtime
...

I'm not sure what those bad mtime's are on my install!

lodash: mapping array to object

You should be using _.keyBy to easily convert an array to an object.

Docs here

Example usage below:

_x000D_
_x000D_
var params = [_x000D_
    { name: 'foo', input: 'bar' },_x000D_
    { name: 'baz', input: 'zle' }_x000D_
];_x000D_
console.log(_.keyBy(params, 'name'));
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>
_x000D_
_x000D_
_x000D_

If required, you can manipulate the array before using _.keyBy or the object after using _.keyBy to get the exact desired result.

Increase permgen space

if you found out that the memory settings were not being used and in order to change the memory settings, I used the tomcat7w or tomcat8w in the \bin folder.Then the following should pop up:

tomcat monitor

Click the Java tab and add the arguments.restart tomcat

Options for initializing a string array

string[] str = new string[]{"1","2"};
string[] str = new string[4];

SyntaxError: Non-ASCII character '\xa3' in file when function returns '£'

First add the # -*- coding: utf-8 -*- line to the beginning of the file and then use u'foo' for all your non-ASCII unicode data:

def NewFunction():
    return u'£'

or use the magic available since Python 2.6 to make it automatic:

from __future__ import unicode_literals

How to update multiple columns in single update statement in DB2

For the sake of completeness and the edge case of wanting to update all columns of a row, you can do the following, but consider that the number and types of the fields must match.

Using a data structure

exec sql UPDATE TESTFILE
         SET ROW = :DataDs
         WHERE CURRENT OF CURSOR; //If using a cursor for update

Source: rpgpgm.com

SQL only

UPDATE t1 SET ROW = (SELECT *
                     FROM   t2
                     WHERE  t2.c3 = t1.c3)

Source: ibm.com

How to store array or multiple values in one column

You have a couple of questions here, so I'll address them separately:

I need to store a number of selected items in one field in a database

My general rule is: don't. This is something which all but requires a second table (or third) with a foreign key. Sure, it may seem easier now, but what if the use case comes along where you need to actually query for those items individually? It also means that you have more options for lazy instantiation and you have a more consistent experience across multiple frameworks/languages. Further, you are less likely to have connection timeout issues (30,000 characters is a lot).

You mentioned that you were thinking about using ENUM. Are these values fixed? Do you know them ahead of time? If so this would be my structure:

Base table (what you have now):

| id primary_key sequence
| -- other columns here.

Items table:

| id primary_key sequence
| descript VARCHAR(30) UNIQUE

Map table:

| base_id  bigint
| items_id bigint

Map table would have foreign keys so base_id maps to Base table, and items_id would map to the items table.

And if you'd like an easy way to retrieve this from a DB, then create a view which does the joins. You can even create insert and update rules so that you're practically only dealing with one table.

What format should I use store the data?

If you have to do something like this, why not just use a character delineated string? It will take less processing power than a CSV, XML, or JSON, and it will be shorter.

What column type should I use store the data?

Personally, I would use TEXT. It does not sound like you'd gain much by making this a BLOB, and TEXT, in my experience, is easier to read if you're using some form of IDE.

Exception: Unexpected end of ZLIB input stream

You have to call close() on the GZIPOutputStream before you attempt to read it. The final bytes of the file will only be written when the file is actually closed. (This is irrespective of any explicit buffering in the output stack. The stream only knows to compress and write the last bytes when you tell it to close. A flush() probably won't help ... though calling finish() instead of close() should work. Look at the javadocs.)

Here's the correct code (in Java);

package test;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GZipTest {

    public static void main(String[] args) throws
                FileNotFoundException, IOException {
        String name = "/tmp/test";
        GZIPOutputStream gz = new GZIPOutputStream(new FileOutputStream(name));
        gz.write(10);
        gz.close();       // Remove this to reproduce the reported bug
        System.out.println(new GZIPInputStream(new FileInputStream(name)).read());
    }
}

(I've not implemented resource management or exception handling / reporting properly as they are not relevant to the purpose of this code. Don't treat this as an example of "good code".)

PHP Create and Save a txt file to root directory

fopen() will open a resource in the same directory as the file executing the command. In other words, if you're just running the file ~/test.php, your script will create ~/myText.txt.

This can get a little confusing if you're using any URL rewriting (such as in an MVC framework) as it will likely create the new file in whatever the directory contains the root index.php file.

Also, you must have correct permissions set and may want to test before writing to the file. The following would help you debug:

$fp = fopen("myText.txt","wb");
if( $fp == false ){
    //do debugging or logging here
}else{
    fwrite($fp,$content);
    fclose($fp);
}

How to set enum to null

I'm assuming c++ here. If you're using c#, the answer is probably the same, but the syntax will be a bit different. The enum is a set of int values. It's not an object, so you shouldn't be setting it to null. Setting something to null means you are pointing a pointer to an object to address zero. You can't really do that with an int. What you want to do with an int is to set it to a value you wouldn't normally have it at so that you can tel if it's a good value or not. So, set your colour to -1

Color color = -1;

Or, you can start your enum at 1 and set it to zero. If you set the colour to zero as it is right now, you will be setting it to "red" because red is zero in your enum.

So,

enum Color {
red =1
blue,
green
}
//red is 1, blue is 2, green is 3
Color mycolour = 0;

Set Google Chrome as the debugging browser in Visual Studio

Click on the arrow near by start button there you will get list of browser. Select the browser you want your application to be run with and click on "Set as Default" Click ok and you are done with this.

Counting the number of elements with the values of x in a vector

This can be done with outer to get a metrix of equalities followed by rowSums, with an obvious meaning.
In order to have the counts and numbers in the same dataset, a data.frame is first created. This step is not needed if you want separate input and output.

df <- data.frame(No = numbers)
df$count <- rowSums(outer(df$No, df$No, FUN = `==`))

Generate signed apk android studio

I had the same problem. I populated the field with /home/tim/android.jks file from tutorial thinking that file would be created. and when i would click enter it would say cant find the file. but when i would try to create the file, it would not let me create the jks file. I closed out of android studio and ran it again and it worked fine. I had to hit the ... to correctly add my file. generate signed apk wizard-->new key store-->hit ... choose key store file. enter filename I was thinking i was going to have to use openjdk and create my own keyfile, but it is built into android studio

:before and background-image... should it work?

Background images on :before and :after elements should work. If you post an example I could probably tell you why it does not work in your case.

Here is an example: http://jsfiddle.net/namas/3/

You can specify the dimensions of the element in % by using background-size: 100% 100% (width / height), for example.

"SetPropertiesRule" warning message when starting Tomcat from Eclipse

I respect all the solutions given here.

But what I came to know after reading all these, we haven't observed that on which folder the struts.xml file or any configuration file which is necessary for the web application.

My SOULUTION IS:

  1. copy the struts.xml file to the src folder of our project.
  2. click "file-->save all" in eclipse and go click "project-->clean".
  3. restart the server.

Hope the problem solved.

Changing minDate and maxDate on the fly using jQuery DatePicker

I have changed min date property of date time picker by using this

$('#date').data("DateTimePicker").minDate(startDate);

I hope this one help to someone !

Pointers in C: when to use the ampersand and the asterisk?

Ok, looks like your post got editted...

double foo[4];
double *bar_1 = &foo[0];

See how you can use the & to get the address of the beginning of the array structure? The following

Foo_1(double *bar, int size){ return bar[size-1]; }
Foo_2(double bar[], int size){ return bar[size-1]; }

will do the same thing.

Javascript / Chrome - How to copy an object from the webkit inspector as code

You can now accomplish this in Chrome by right clicking on the object and selecting "Store as Global Variable": http://www.youtube.com/watch?v=qALFiTlVWdg

enter image description here

Parse JSON object with string and value only

My pseudocode example will be as follows:

JSONArray jsonArray = "[{id:\"1\", name:\"sql\"},{id:\"2\",name:\"android\"},{id:\"3\",name:\"mvc\"}]";
JSON newJson = new JSON();

for (each json in jsonArray) {
    String id = json.get("id");
    String name = json.get("name");

    newJson.put(id, name);
}

return newJson;

Are there any free Xml Diff/Merge tools available?

While this is not a GUI tool, my quick tests indicated that diffxml has some promise. The author appears to have thought about the complexities of representing diffs for nested elements in a standardized way (his DUL - Delta Update Language specification).

Installing and running his tools, I can say that the raw text output is quite clear and concise. It doesn't offer the same degree of immediate apprehension as a GUI tool, but given that the output is standardized as DUL, perhaps you would be able to take that and build a tool to generate a visual representation. I'd certainly love to see one.

The author's "links" section does reference a few other XML differencing tools, but as you mentioned in your post, they're all proprietary.

PuTTY scripting to log onto host

I'm not sure why previous answers haven't suggested that the original poster set up a shell profile (bashrc, .tcshrc, etc.) that executed their commands automatically every time they log in on the server side.

The quest that brought me to this page for help was a bit different -- I wanted multiple PuTTY shortcuts for the same host that would execute different startup commands.

I came up with two solutions, both of which worked:

(background) I have a folder with a variety of PuTTY shortcuts, each with the "target" property in the shortcut tab looking something like:

"C:\Program Files (x86)\PuTTY\putty.exe" -load host01

with each load corresponding to a PuTTY profile I'd saved (with different hosts in the "Session" tab). (Mostly they only differ in color schemes -- I like to have each group of related tasks share a color scheme in the terminal window, with critical tasks, like logging in as root on a production system, performed only in distinctly colored windows.)

The folder's Windows properties are set to very clean and stripped down -- it functions as a small console with shortcut icons for each of my frequent remote PuTTY and RDP connections.

(solution 1) As mentioned in other answers the -m switch is used to configure a script on the Windows side to run, the -t switch is used to stay connected, but I found that it was order-sensitive if I wanted to get it to run without exiting

What I finally got to work after a lot of trial and error was:

(shortcut target field):

"C:\Program Files (x86)\PuTTY\putty.exe" -t -load "SSH Proxy" -m "C:\Users\[me]\Documents\hello-world-bash.txt"

where the file being executed looked like

echo "Hello, World!"
echo ""
export PUTTYVAR=PROXY
/usr/local/bin/bash

(no semicolons needed)

This runs the scripted command (in my case just printing "Hello, world" on the terminal) and sets a variable that my remote session can interact with.

Note for debugging: when you run PuTTY it loads the -m script, if you edit the script you need to re-launch PuTTY instead of just restarting the session.

(solution 2) This method feels a lot cleaner, as the brains are on the remote Unix side instead of the local Windows side:

From Putty master session (not "edit settings" from existing session) load a saved config and in the SSH tab set remote command to:

export PUTTYVAR=GREEN; bash -l

Then, in my .bashrc, I have a section that performs different actions based on that variable:

case ${PUTTYVAR} in
  "")
    echo "" 
    ;;
  "PROXY")
    # this is the session config with all the SSH tunnels defined in it
    echo "";
    echo "Special window just for holding tunnels open." ;
    echo "";
    PROMPT_COMMAND='echo -ne "\033]0;Proxy Session @master01\$\007"'
    alias temppass="ssh keyholder.example.com makeonetimepassword"
    alias | grep temppass
    ;;
  "GREEN")
    echo "";
    echo "It's not easy being green"
    ;;
  "GRAY")
    echo ""
    echo "The gray ghost"
    ;;
  *)
    echo "";
    echo "Unknown PUTTYVAR setting ${PUTTYVAR}"
    ;;
esac

(solution 3, untried)

It should also be possible to have bash skip my .bashrc and execute a different startup script, by putting this in the PuTTY SSH command field:

bash --rcfile .bashrc_variant -l 

Where to find free public Web Services?

Here you can find some public REST services for encryption and security related things: http://security.jelastic.servint.net

How to enable PHP's openssl extension to install Composer?

For those who're having the same problem as I was. After doing all the solutions above, still didn't work for me. I found out that, uWamp was creating the PHP.INI file in bin/apache directory. So I had to copy the PHP.INI file into php installation directory, that is, bin/php/phpXXXX directory. This should also be where the php.exe is that you selected from the composer setup.

Hope this helps.

Retrieving a Foreign Key value with django-rest-framework serializers

this worked fine for me:

class ItemSerializer(serializers.ModelSerializer):
    category_name = serializers.ReadOnlyField(source='category.name')
    class Meta:
        model = Item
        fields = "__all__"

What exactly is a Maven Snapshot and why do we need it?

understanding the context of SDLC will help understand the difference between snapshot and the release. During the dev process developers all contribute their features to a baseline branch. At some point the lead thinks enough features have accumulated then he will cut a release branch from the baseline branch. Any builds prior to this time point are snapshots. Builds post to this point are releases. Be noted, release builds could change too before going to production if any defect spot during the release testing.

How are people unit testing with Entity Framework 6, should you bother?

This is a topic I'm very interested in. There are many purists who say that you shouldn't test technologies such as EF and NHibernate. They are right, they're already very stringently tested and as a previous answer stated it's often pointless to spend vast amounts of time testing what you don't own.

However, you do own the database underneath! This is where this approach in my opinion breaks down, you don't need to test that EF/NH are doing their jobs correctly. You need to test that your mappings/implementations are working with your database. In my opinion this is one of the most important parts of a system you can test.

Strictly speaking however we're moving out of the domain of unit testing and into integration testing but the principles remain the same.

The first thing you need to do is to be able to mock your DAL so your BLL can be tested independently of EF and SQL. These are your unit tests. Next you need to design your Integration Tests to prove your DAL, in my opinion these are every bit as important.

There are a couple of things to consider:

  1. Your database needs to be in a known state with each test. Most systems use either a backup or create scripts for this.
  2. Each test must be repeatable
  3. Each test must be atomic

There are two main approaches to setting up your database, the first is to run a UnitTest create DB script. This ensures that your unit test database will always be in the same state at the beginning of each test (you may either reset this or run each test in a transaction to ensure this).

Your other option is what I do, run specific setups for each individual test. I believe this is the best approach for two main reasons:

  • Your database is simpler, you don't need an entire schema for each test
  • Each test is safer, if you change one value in your create script it doesn't invalidate dozens of other tests.

Unfortunately your compromise here is speed. It takes time to run all these tests, to run all these setup/tear down scripts.

One final point, it can be very hard work to write such a large amount of SQL to test your ORM. This is where I take a very nasty approach (the purists here will disagree with me). I use my ORM to create my test! Rather than having a separate script for every DAL test in my system I have a test setup phase which creates the objects, attaches them to the context and saves them. I then run my test.

This is far from the ideal solution however in practice I find it's a LOT easier to manage (especially when you have several thousand tests), otherwise you're creating massive numbers of scripts. Practicality over purity.

I will no doubt look back at this answer in a few years (months/days) and disagree with myself as my approaches have changed - however this is my current approach.

To try and sum up everything I've said above this is my typical DB integration test:

[Test]
public void LoadUser()
{
  this.RunTest(session => // the NH/EF session to attach the objects to
  {
    var user = new UserAccount("Mr", "Joe", "Bloggs");
    session.Save(user);
    return user.UserID;
  }, id => // the ID of the entity we need to load
  {
     var user = LoadMyUser(id); // load the entity
     Assert.AreEqual("Mr", user.Title); // test your properties
     Assert.AreEqual("Joe", user.Firstname);
     Assert.AreEqual("Bloggs", user.Lastname);
  }
}

The key thing to notice here is that the sessions of the two loops are completely independent. In your implementation of RunTest you must ensure that the context is committed and destroyed and your data can only come from your database for the second part.

Edit 13/10/2014

I did say that I'd probably revise this model over the upcoming months. While I largely stand by the approach I advocated above I've updated my testing mechanism slightly. I now tend to create the entities in in the TestSetup and TestTearDown.

[SetUp]
public void Setup()
{
  this.SetupTest(session => // the NH/EF session to attach the objects to
  {
    var user = new UserAccount("Mr", "Joe", "Bloggs");
    session.Save(user);
    this.UserID =  user.UserID;
  });
}

[TearDown]
public void TearDown()
{
   this.TearDownDatabase();
}

Then test each property individually

[Test]
public void TestTitle()
{
     var user = LoadMyUser(this.UserID); // load the entity
     Assert.AreEqual("Mr", user.Title);
}

[Test]
public void TestFirstname()
{
     var user = LoadMyUser(this.UserID);
     Assert.AreEqual("Joe", user.Firstname);
}

[Test]
public void TestLastname()
{
     var user = LoadMyUser(this.UserID);
     Assert.AreEqual("Bloggs", user.Lastname);
}

There are several reasons for this approach:

  • There are no additional database calls (one setup, one teardown)
  • The tests are far more granular, each test verifies one property
  • Setup/TearDown logic is removed from the Test methods themselves

I feel this makes the test class simpler and the tests more granular (single asserts are good)

Edit 5/3/2015

Another revision on this approach. While class level setups are very helpful for tests such as loading properties they are less useful where the different setups are required. In this case setting up a new class for each case is overkill.

To help with this I now tend to have two base classes SetupPerTest and SingleSetup. These two classes expose the framework as required.

In the SingleSetup we have a very similar mechanism as described in my first edit. An example would be

public TestProperties : SingleSetup
{
  public int UserID {get;set;}

  public override DoSetup(ISession session)
  {
    var user = new User("Joe", "Bloggs");
    session.Save(user);
    this.UserID = user.UserID;
  }

  [Test]
  public void TestLastname()
  {
     var user = LoadMyUser(this.UserID); // load the entity
     Assert.AreEqual("Bloggs", user.Lastname);
  }

  [Test]
  public void TestFirstname()
  {
       var user = LoadMyUser(this.UserID);
       Assert.AreEqual("Joe", user.Firstname);
  }
}

However references which ensure that only the correct entites are loaded may use a SetupPerTest approach

public TestProperties : SetupPerTest
{
   [Test]
   public void EnsureCorrectReferenceIsLoaded()
   {
      int friendID = 0;
      this.RunTest(session =>
      {
         var user = CreateUserWithFriend();
         session.Save(user);
         friendID = user.Friends.Single().FriendID;
      } () =>
      {
         var user = GetUser();
         Assert.AreEqual(friendID, user.Friends.Single().FriendID);
      });
   }
   [Test]
   public void EnsureOnlyCorrectFriendsAreLoaded()
   {
      int userID = 0;
      this.RunTest(session =>
      {
         var user = CreateUserWithFriends(2);
         var user2 = CreateUserWithFriends(5);
         session.Save(user);
         session.Save(user2);
         userID = user.UserID;
      } () =>
      {
         var user = GetUser(userID);
         Assert.AreEqual(2, user.Friends.Count());
      });
   }
}

In summary both approaches work depending on what you are trying to test.

How to study design patterns?

The best way is to begin coding with them. Design patterns are a great concept that are hard to apply from just reading about them. Take some sample implementations that you find online and build up around them.

A great resource is the Data & Object Factory page. They go over the patterns, and give you both conceptual and real world examples. Their reference material is great, too.

nvm keeps "forgetting" node in new terminal session

Try nvm alias default. For example:

$ nvm alias default 0.12.7

This sets the default node version in your shell. Then verify that the change persists by closing the shell window, opening a new one, then: node --version

Naming conventions for Java methods that return boolean

The convention is to ask a question in the name.

Here are a few examples that can be found in the JDK:

isEmpty()

hasChildren()

That way, the names are read like they would have a question mark on the end.

Is the Collection empty?
Does this Node have children?

And, then, true means yes, and false means no.

Or, you could read it like an assertion:

The Collection is empty.
The node has children

Note:
Sometimes you may want to name a method something like createFreshSnapshot?. Without the question mark, the name implies that the method should be creating a snapshot, instead of checking to see if one is required.

In this case you should rethink what you are actually asking. Something like isSnapshotExpired is a much better name, and conveys what the method will tell you when it is called. Following a pattern like this can also help keep more of your functions pure and without side effects.

If you do a Google Search for isEmpty() in the Java API, you get lots of results.

Sort Pandas Dataframe by Date

@JAB's answer is fast and concise. But it changes the DataFrame you are trying to sort, which you may or may not want.

(Note: You almost certainly will want it, because your date columns should be dates, not strings!)

In the unlikely event that you don't want to change the dates into dates, you can also do it a different way.

First, get the index from your sorted Date column:

In [25]: pd.to_datetime(df.Date).order().index
Out[25]: Int64Index([0, 2, 1], dtype='int64')

Then use it to index your original DataFrame, leaving it untouched:

In [26]: df.ix[pd.to_datetime(df.Date).order().index]
Out[26]: 
        Date Symbol
0 2015-02-20      A
2 2015-08-21      A
1 2016-01-15      A

Magic!

Note: for Pandas versions 0.20.0 and later, use loc instead of ix, which is now deprecated.

What is the meaning of 'No bundle URL present' in react-native?

I tried most of answers above. But the only that works for is a watchman command(I use react-native: "0.60.4"):

watchman watch-del-all

Android Studio - Importing external Library/Jar

In Android Studio (mine is 2.3.1) go to File - Project Structure:

enter image description here

How to printf uint64_t? Fails with: "spurious trailing ‘%’ in format"

Since you've included the C++ tag, you could use the {fmt} library and avoid the PRIu64 macro and other printf issues altogether:

#include <fmt/core.h>

int main() {
  uint64_t ui64 = 90;
  fmt::print("test uint64_t : {}\n", ui64);
}

The formatting facility based on this library is proposed for standardization in C++20: P0645.

Disclaimer: I'm the author of {fmt}.

Convert List to Pandas Dataframe Column

Use:

L = ['Thanks You', 'Its fine no problem', 'Are you sure']

#create new df 
df = pd.DataFrame({'col':L})
print (df)

                   col
0           Thanks You
1  Its fine no problem
2         Are you sure

df = pd.DataFrame({'oldcol':[1,2,3]})

#add column to existing df 
df['col'] = L
print (df)
   oldcol                  col
0       1           Thanks You
1       2  Its fine no problem
2       3         Are you sure

Thank you DYZ:

#default column name 0
df = pd.DataFrame(L)
print (df)
                     0
0           Thanks You
1  Its fine no problem
2         Are you sure

Returning unique_ptr from functions

unique_ptr doesn't have the traditional copy constructor. Instead it has a "move constructor" that uses rvalue references:

unique_ptr::unique_ptr(unique_ptr && src);

An rvalue reference (the double ampersand) will only bind to an rvalue. That's why you get an error when you try to pass an lvalue unique_ptr to a function. On the other hand, a value that is returned from a function is treated as an rvalue, so the move constructor is called automatically.

By the way, this will work correctly:

bar(unique_ptr<int>(new int(44));

The temporary unique_ptr here is an rvalue.

Print ArrayList

public void printList(ArrayList<Address> list){
    for(Address elem : list){
        System.out.println(elem+"  ");
    }
}

How to uninstall Golang?

Use this command to uninstall Golang for Ubuntu.

This will remove just the golang-go package itself.

sudo apt-get remove golang-go

Uninstall golang-go and its dependencies:

sudo apt-get remove --auto-remove golang-go

Error handling in Bash

That's a fine solution. I just wanted to add

set -e

as a rudimentary error mechanism. It will immediately stop your script if a simple command fails. I think this should have been the default behavior: since such errors almost always signify something unexpected, it is not really 'sane' to keep executing the following commands.

What is the use of adding a null key or value to a HashMap in Java?

One example would be for modeling trees. If you are using a HashMap to represent a tree structure, where the key is the parent and the value is list of children, then the values for the null key would be the root nodes.

Iterator invalidation rules

C++17 (All references are from the final working draft of CPP17 - n4659)


Insertion

Sequence Containers

  • vector: The functions insert, emplace_back, emplace, push_back cause reallocation if the new size is greater than the old capacity. Reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. If no reallocation happens, all the iterators and references before the insertion point remain valid. [26.3.11.5/1]
    With respect to the reserve function, reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. No reallocation shall take place during insertions that happen after a call to reserve() until the time when an insertion would make the size of the vector greater than the value of capacity(). [26.3.11.3/6]

  • deque: An insertion in the middle of the deque invalidates all the iterators and references to elements of the deque. An insertion at either end of the deque invalidates all the iterators to the deque, but has no effect on the validity of references to elements of the deque. [26.3.8.4/1]

  • list: Does not affect the validity of iterators and references. If an exception is thrown there are no effects. [26.3.10.4/1].
    The insert, emplace_front, emplace_back, emplace, push_front, push_back functions are covered under this rule.

  • forward_list: None of the overloads of insert_after shall affect the validity of iterators and references [26.3.9.5/1]

  • array: As a rule, iterators to an array are never invalidated throughout the lifetime of the array. One should take note, however, that during swap, the iterator will continue to point to the same array element, and will thus change its value.

Associative Containers

  • All Associative Containers: The insert and emplace members shall not affect the validity of iterators and references to the container [26.2.6/9]

Unordered Associative Containers

  • All Unordered Associative Containers: Rehashing invalidates iterators, changes ordering between elements, and changes which buckets elements appear in, but does not invalidate pointers or references to elements. [26.2.7/9]
    The insert and emplace members shall not affect the validity of references to container elements, but may invalidate all iterators to the container. [26.2.7/14]
    The insert and emplace members shall not affect the validity of iterators if (N+n) <= z * B, where N is the number of elements in the container prior to the insert operation, n is the number of elements inserted, B is the container’s bucket count, and z is the container’s maximum load factor. [26.2.7/15]

  • All Unordered Associative Containers: In case of a merge operation (e.g., a.merge(a2)), iterators referring to the transferred elements and all iterators referring to a will be invalidated, but iterators to elements remaining in a2 will remain valid. (Table 91 — Unordered associative container requirements)

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

Erasure

Sequence Containers

  • vector: The functions erase and pop_back invalidate iterators and references at or after the point of the erase. [26.3.11.5/3]

  • deque: An erase operation that erases the last element of a deque invalidates only the past-the-end iterator and all iterators and references to the erased elements. An erase operation that erases the first element of a deque but not the last element invalidates only iterators and references to the erased elements. An erase operation that erases neither the first element nor the last element of a deque invalidates the past-the-end iterator and all iterators and references to all the elements of the deque. [ Note: pop_front and pop_back are erase operations. —end note ] [26.3.8.4/4]

  • list: Invalidates only the iterators and references to the erased elements. [26.3.10.4/3]. This applies to erase, pop_front, pop_back, clear functions.
    remove and remove_if member functions: Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value, pred(*i) != false. Invalidates only the iterators and references to the erased elements [26.3.10.5/15].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version of unique with no arguments) or pred(*i, *(i - 1)) (for the version of unique with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. [26.3.10.5/19]

  • forward_list: erase_after shall invalidate only iterators and references to the erased elements. [26.3.9.5/1].
    remove and remove_if member functions - Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value (for remove()), pred(*i) is true (for remove_if()). Invalidates only the iterators and references to the erased elements. [26.3.9.6/12].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version with no arguments) or pred(*i, *(i - 1)) (for the version with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. [26.3.9.6/16]

  • All Sequence Containers: clear invalidates all references, pointers, and iterators referring to the elements of a and may invalidate the past-the-end iterator (Table 87 — Sequence container requirements). But for forward_list, clear does not invalidate past-the-end iterators. [26.3.9.5/32]

  • All Sequence Containers: assign invalidates all references, pointers and iterators referring to the elements of the container. For vector and deque, also invalidates the past-the-end iterator. (Table 87 — Sequence container requirements)

Associative Containers

  • All Associative Containers: The erase members shall invalidate only iterators and references to the erased elements [26.2.6/9]

  • All Associative Containers: The extract members invalidate only iterators to the removed element; pointers and references to the removed element remain valid [26.2.6/10]

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

General container requirements relating to iterator invalidation:

  • Unless otherwise specified (either explicitly or by defining a function in terms of other functions), invoking a container member function or passing a container as an argument to a library function shall not invalidate iterators to, or change the values of, objects within that container. [26.2.1/12]

  • no swap() function invalidates any references, pointers, or iterators referring to the elements of the containers being swapped. [ Note: The end() iterator does not refer to any element, so it may be invalidated. —end note ] [26.2.1/(11.6)]

As examples of the above requirements:

  • transform algorithm: The op and binary_op functions shall not invalidate iterators or subranges, or modify elements in the ranges [28.6.4/1]

  • accumulate algorithm: In the range [first, last], binary_op shall neither modify elements nor invalidate iterators or subranges [29.8.2/1]

  • reduce algorithm: binary_op shall neither invalidate iterators or subranges, nor modify elements in the range [first, last]. [29.8.3/5]

and so on...

SQL Server - after insert trigger - update another column in the same table

Another option would be to enclose the update statement in an IF statement and call TRIGGER_NESTLEVEL() to restrict the update being run a second time.

CREATE TRIGGER Table_A_Update ON Table_A AFTER UPDATE 
AS
IF ((SELECT TRIGGER_NESTLEVEL()) < 2)
BEGIN
    UPDATE a
    SET Date_Column = GETDATE()
    FROM Table_A a
    JOIN inserted i ON a.ID = i.ID
END

When the trigger initially runs the TRIGGER_NESTLEVEL is set to 1 so the update statement will be executed. That update statement will in turn fire that same trigger except this time the TRIGGER_NESTLEVEL is set to 2 and the update statement will not be executed.

You could also check the TRIGGER_NESTLEVEL first and if its greater than 1 then call RETURN to exit out of the trigger.

IF ((SELECT TRIGGER_NESTLEVEL()) > 1) RETURN;

SimpleDateFormat and locale based format string

Java 8 Style for a given date

LocalDate today = LocalDate.of(1982, Month.AUGUST, 31);
System.out.println(today.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(Locale.ENGLISH)));
System.out.println(today.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(Locale.FRENCH)));
System.out.println(today.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(Locale.JAPANESE)));

Import error: No module name urllib2

As stated in the urllib2 documentation:

The urllib2 module has been split across several modules in Python 3 named urllib.request and urllib.error. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.

So you should instead be saying

from urllib.request import urlopen
html = urlopen("http://www.google.com/").read()
print(html)

Your current, now-edited code sample is incorrect because you are saying urllib.urlopen("http://www.google.com/") instead of just urlopen("http://www.google.com/").

Graphical DIFF programs for linux

I know of two graphical diff programs: Meld and KDiff3. I haven't used KDiff3, but Meld works well for me.

It seems that both are in the standard package repositories for openSUSE 11.0

How do I get the full path to a Perl script that is executing?

The problem with __FILE__ is that it will print the core module ".pm" path not necessarily the ".cgi" or ".pl" script path that is running. I guess it depends on what your goal is.

It seems to me that Cwd just needs to be updated for mod_perl. Here is my suggestion:

my $path;

use File::Basename;
my $file = basename($ENV{SCRIPT_NAME});

if (exists $ENV{MOD_PERL} && ($ENV{MOD_PERL_API_VERSION} < 2)) {
  if ($^O =~/Win/) {
    $path = `echo %cd%`;
    chop $path;
    $path =~ s!\\!/!g;
    $path .= $ENV{SCRIPT_NAME};
  }
  else {
    $path = `pwd`;
    $path .= "/$file";
  }
  # add support for other operating systems
}
else {
  require Cwd;
  $path = Cwd::getcwd()."/$file";
}
print $path;

Please add any suggestions.

How do I find the value of $CATALINA_HOME?

Tomcat can tell you in several ways. Here's the easiest:

 $ /path/to/catalina.sh version
Using CATALINA_BASE:   /usr/local/apache-tomcat-7.0.29
Using CATALINA_HOME:   /usr/local/apache-tomcat-7.0.29
Using CATALINA_TMPDIR: /usr/local/apache-tomcat-7.0.29/temp
Using JRE_HOME:        /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home
Using CLASSPATH:       /usr/local/apache-tomcat-7.0.29/bin/bootstrap.jar:/usr/local/apache-tomcat-7.0.29/bin/tomcat-juli.jar
Server version: Apache Tomcat/7.0.29
Server built:   Jul 3 2012 11:31:52
Server number:  7.0.29.0
OS Name:        Mac OS X
OS Version:     10.7.4
Architecture:   x86_64
JVM Version:    1.6.0_33-b03-424-11M3720
JVM Vendor:     Apple Inc.

If you don't know where catalina.sh is (or it never gets called), you can usually find it via ps:

$ ps aux | grep catalina
chris            930   0.0  3.1  2987336 258328 s000  S    Wed01PM   2:29.43 /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java -Dnop -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.library.path=/usr/local/apache-tomcat-7.0.29/lib -Djava.endorsed.dirs=/usr/local/apache-tomcat-7.0.29/endorsed -classpath /usr/local/apache-tomcat-7.0.29/bin/bootstrap.jar:/usr/local/apache-tomcat-7.0.29/bin/tomcat-juli.jar -Dcatalina.base=/Users/chris/blah/blah -Dcatalina.home=/usr/local/apache-tomcat-7.0.29 -Djava.io.tmpdir=/Users/chris/blah/blah/temp org.apache.catalina.startup.Bootstrap start

From the ps output, you can see both catalina.home and catalina.base. catalina.home is where the Tomcat base files are installed, and catalina.base is where the running configuration of Tomcat exists. These are often set to the same value unless you have configured your Tomcat for multiple (configuration) instances to be launched from a single Tomcat base install.

You can also interrogate the JVM directly if you can't find it in a ps listing:

$ jinfo -sysprops 930 | grep catalina
Attaching to process ID 930, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 20.8-b03-424
catalina.base = /Users/chris/blah/blah
[...]
catalina.home = /usr/local/apache-tomcat-7.0.29

If you can't manage that, you can always try to write a JSP that dumps the values of the two system properties catalina.home and catalina.base.

How to grep Git commit diffs or contents for a certain word?

One more way/syntax to do it is: git log -S "word"
Like this you can search for example git log -S "with whitespaces and stuff @/#ü !"

Runtime error: Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0

I got this problem because I uninstalled VS 2012, I don't want to reinstall it back, so I downloaded the AspNetMVC4Setup.exe from Microsoft.com and fixed my problem.

https://www.microsoft.com/en-us/download/details.aspx?id=30683

Pure CSS checkbox image replacement

Using javascript seems to be unnecessary if you choose CSS3.

By using :before selector, you can do this in two lines of CSS. (no script involved).

Another advantage of this approach is that it does not rely on <label> tag and works even it is missing.

Note: in browsers without CSS3 support, checkboxes will look normal. (backward compatible).

input[type=checkbox]:before { content:""; display:inline-block; width:12px; height:12px; background:red; }
input[type=checkbox]:checked:before { background:green; }?

You can see a demo here: http://jsfiddle.net/hqZt6/1/

and this one with images:

http://jsfiddle.net/hqZt6/6/

Get Specific Columns Using “With()” Function in Laravel Eloquent

You can try this code . It is tested in laravel 6 version.

Controller code
 public function getSection(Request $request)
{

  Section::with(['sectionType' => function($q) {
      $q->select('id', 'name');
  }])->where('position',1)->orderBy('serial_no', 'asc')->get(['id','name','','description']);
  return response()->json($getSection);
}
Model code
public function sectionType(){
    return $this->belongsTo(Section_Type::class, 'type_id');
}

What are my options for storing data when using React Native? (iOS and Android)

Quick and dirty: just use Redux + react-redux + redux-persist + AsyncStorage for react-native.

It fits almost perfectly the react native world and works like a charm for both android and ios. Also, there is a solid community around it, and plenty of information.

For a working example, see the F8App from Facebook.

What are the different options for data persistence?

With react native, you probably want to use redux and redux-persist. It can use multiple storage engines. AsyncStorage and redux-persist-filesystem-storage are the options for RN.

There are other options like Firebase or Realm, but I never used those on a RN project.

For each, what are the limits of that persistence (i.e., when is the data no longer available)? For example: when closing the application, restarting the phone, etc.

Using redux + redux-persist you can define what is persisted and what is not. When not persisted, data exists while the app is running. When persisted, the data persists between app executions (close, open, restart phone, etc).

AsyncStorage has a default limit of 6MB on Android. It is possible to configure a larger limit (on Java code) or use redux-persist-filesystem-storage as storage engine for Android.

For each, are there differences (other than general setup) between implementing in iOS vs Android?

Using redux + redux-persist + AsyncStorage the setup is exactly the same on android and iOS.

How do the options compare for accessing data offline? (or how is offline access typically handled?)

Using redux, offiline access is almost automatic thanks to its design parts (action creators and reducers).

All data you fetched and stored are available, you can easily store extra data to indicate the state (fetching, success, error) and the time it was fetched. Normally, requesting a fetch does not invalidate older data and your components just update when new data is received.

The same apply in the other direction. You can store data you are sending to server and that are still pending and handle it accordingly.

Are there any other considerations I should keep in mind?

React promotes a reactive way of creating apps and Redux fits very well on it. You should try it before just using an option you would use in your regular Android or iOS app. Also, you will find much more docs and help for those.

UILabel font size?

Try to change your label frame size height and width so your text not cut.

 [label setframe:CGRect(x,y,widht,height)];

EF Migrations: Rollback last applied migration?

EF CORE

PM> Update-Database yourMigrationName

(reverts the migration)

PM> Update-Database

worked for me

in this case the original question (yourMigrationName = CategoryIdIsLong)

How to horizontally center an unordered list of unknown width?

One more solution:

#footer { display:table; margin:0 auto; }
#footer li { display:table-cell; padding: 0px 10px; }

Then ul doesn't jump to the next line in case of zooming text.

Pandas split column of lists into multiple columns

There seems to be a syntactically simpler way, and therefore easier to remember, as opposed to the proposed solutions. I'm assuming that the column is called 'meta' in a dataframe df:

df2 = pd.DataFrame(df['meta'].str.split().values.tolist())

How do I prevent Conda from activating the base environment by default?

So in the end I found that if I commented out the Conda initialisation block like so:

# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
# __conda_setup="$('/Users/geoff/anaconda2/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
# if [ $? -eq 0 ]; then
    # eval "$__conda_setup"
# else
if [ -f "/Users/geoff/anaconda2/etc/profile.d/conda.sh" ]; then
    . "/Users/geoff/anaconda2/etc/profile.d/conda.sh"
else
    export PATH="/Users/geoff/anaconda2/bin:$PATH"
fi
# fi
# unset __conda_setup
# <<< conda initialize <<<

It works exactly how I want. That is, Conda is available to activate an environment if I want, but doesn't activate by default.

python: iterate a specific range in a list

A more memory efficient way to iterate over a slice of a list would be to use islice() from the itertools module:

from itertools import islice

listOfStuff = (['a','b'], ['c','d'], ['e','f'], ['g','h'])

for item in islice(listOfStuff, 1, 3):
    print item

# ['c', 'd']
# ['e', 'f']

However, this can be relatively inefficient in terms of performance if the start value of the range is a large value sinceislicewould have to iterate over the first start value-1 items before returning items.

docker: Error response from daemon: Get https://registry-1.docker.io/v2/: Service Unavailable. IN DOCKER , MAC

Just to add, in case anyone else comes across this issue.

On a Mac I had to logout and log back in.

docker logout

docker login 

Then it prompts for username (NOTE: Not email) and password. (Need an account on https://hub.docker.com to pull images down)

Then it worked for me.

moment.js get current time in milliseconds?

To get the current time's milliseconds, use http://momentjs.com/docs/#/get-set/millisecond/

var timeInMilliseconds = moment().milliseconds();

Get a DataTable Columns DataType

You could always use typeof in the if statement. It is better than working with string values like the answer of Natarajan.

if (dt.Columns[0].DataType == typeof(DateTime))
{
}

Check if datetime instance falls in between other two datetime objects

DateTime.Ticks will account for the time. Use .Ticks on the DateTime to convert your dates into longs. Then just use a simple if stmt to see if your target date falls between.

// Assuming you know d2 > d1
if (targetDt.Ticks > d1.Ticks && targetDt.Ticks < d2.Ticks)
{
    // targetDt is in between d1 and d2
}  

How to get the request parameters in Symfony 2?

Most of the cases like getting query string or form parameters are covered in answers above.

When working with raw data, like a raw JSON string in the body that you would like to give as an argument to json_decode(), the method Request::getContent() can be used.

$content = $request->getContent();

Additional useful informations on HTTP requests in Symfony can be found on the HttpFoundation package's documentation.

PANIC: Broken AVD system path. Check your ANDROID_SDK_ROOT value

ok i can run android from cordova, i changed ANDROID_HOME to,

export ANDROID_HOME=/usr/local/opt/android-sdk

HTML Display Current date

Here's one way. You have to get the individual components from the date object (day, month & year) and then build and format the string however you wish.

_x000D_
_x000D_
n =  new Date();_x000D_
y = n.getFullYear();_x000D_
m = n.getMonth() + 1;_x000D_
d = n.getDate();_x000D_
document.getElementById("date").innerHTML = m + "/" + d + "/" + y;
_x000D_
<p id="date"></p>
_x000D_
_x000D_
_x000D_

How to make a div fill a remaining horizontal space?

@Boushley's answer was the closest, however there is one problem not addressed that has been pointed out. The right div takes the entire width of the browser; the content takes the expected width. To see this problem better:

<html>
<head>
    <style type="text/css">
    * { margin: 0; padding: 0; }
    body {
        height: 100%;
    }
    #left {
        opacity: 0;
        height: inherit;
        float: left;
        width: 180px;
        background: green;
    }
    #right {
        height: inherit;
        background: orange;
    }
    table {
            width: 100%;
            background: red;
    }
    </style>
</head>
<body>
    <div id="left">
        <p>Left</p>
    </div>
    <div id="right">
        <table><tr><td>Hello, World!</td></tr></table>
    </div>
</body>
</html>

http://jsfiddle.net/79hpS/

The content is in the correct place (in Firefox), however, the width incorrect. When child elements start inheriting width (e.g. the table with width: 100%) they are given a width equal to that of the browser causing them to overflow off the right of the page and create a horizontal scrollbar (in Firefox) or not float and be pushed down (in chrome).

You can fix this easily by adding overflow: hidden to the right column. This gives you the correct width for both the content and the div. Furthermore, the table will receive the correct width and fill the remaining width available.

I tried some of the other solutions above, they didn't work fully with certain edge cases and were just too convoluted to warrant fixing them. This works and it's simple.

If there are any problems or concerns, feel free to raise them.

c# write text on bitmap

You need to use the Graphics class in order to write on the bitmap.

Specifically, one of the DrawString methods.

Bitmap a = new Bitmap(@"path\picture.bmp");

using(Graphics g = Graphics.FromImage(a))
{
  g.DrawString(....); // requires font, brush etc
}

pictuteBox1.Image = a;

Why won't my PHP app send a 404 error?

That is correct behaviour, it's up to you to create the contents for the 404 page.
The 404 header is used by spiders and download-managers to determine if the file exists.
(A page with a 404 header won't be indexed by google or other search-engines)

Normal users however don't look at http-headers and use the page as a normal page.

How to run Visual Studio post-build events for debug build only

Alternatively (since the events are put into a batch file and then called), use the following (in the Build event box, not in a batch file):

if $(ConfigurationName) == Debug goto :debug

:release
signtool.exe ....
xcopy ...

goto :exit

:debug
' Debug items in here

:exit

This way you can have events for any configuration, and still manage it with the macros rather than having to pass them into a batch file, remember that %1 is $(OutputPath), etc.

Hiding the address bar of a browser (popup)

This is how I do it for popups, though it is only working with IE11, not Chrome- haven't tested in Firefox.

window.open(url, title, 'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no');

Unicode character in PHP string

PHP does not know these Unicode escape sequences. But as unknown escape sequences remain unaffected, you can write your own function that converts such Unicode escape sequences:

function unicodeString($str, $encoding=null) {
    if (is_null($encoding)) $encoding = ini_get('mbstring.internal_encoding');
    return preg_replace_callback('/\\\\u([0-9a-fA-F]{4})/u', create_function('$match', 'return mb_convert_encoding(pack("H*", $match[1]), '.var_export($encoding, true).', "UTF-16BE");'), $str);
}

Or with an anonymous function expression instead of create_function:

function unicodeString($str, $encoding=null) {
    if (is_null($encoding)) $encoding = ini_get('mbstring.internal_encoding');
    return preg_replace_callback('/\\\\u([0-9a-fA-F]{4})/u', function($match) use ($encoding) {
        return mb_convert_encoding(pack('H*', $match[1]), $encoding, 'UTF-16BE');
    }, $str);
}

Its usage:

$str = unicodeString("\u1000");

What is the difference between Scala's case class and class?

  • Case classes define a compagnon object with apply and unapply methods
  • Case classes extends Serializable
  • Case classes define equals hashCode and copy methods
  • All attributes of the constructor are val (syntactic sugar)

Android Emulator: Installation error: INSTALL_FAILED_VERSION_DOWNGRADE

I was having same problem. I was getting error when i tried to run in my android device not emulator.

sudo ionic run android 

I am able to fix this by running

adb uninstall com.mypackage.name

Drop view if exists

your exists syntax is wrong and you should seperate DDL with go like below

if exists(select 1 from sys.views where name='tst' and type='v')
drop view tst;
go

create view tst
as
select * from test

you also can check existence test, with object_id like below

if object_id('tst','v') is not null
drop view tst;
go

create view tst
as
select * from test

In SQL 2016,you can use below syntax to drop

Drop view  if exists dbo.tst

From SQL2016 CU1,you can do below

create or alter view vwTest
as
 select 1 as col;
go

Get the row(s) which have the max value in groups using groupby

For me, the easiest solution would be keep value when count is equal to the maximum. Therefore, the following one line command is enough :

df[df['count'] == df.groupby(['Mt'])['count'].transform(max)]

How to navigate a few folders up?

Other simple way is to do this:

string path = @"C:\Folder1\Folder2\Folder3\Folder4";
string newPath = Path.GetFullPath(Path.Combine(path, @"..\..\"));

Note This goes two levels up. The result would be: newPath = @"C:\Folder1\Folder2\";

Best practices with STDIN in Ruby?

I'll add that in order to use ARGF with parameters, you need to clear ARGV before calling ARGF.each. This is because ARGF will treat anything in ARGV as a filename and read lines from there first.

Here's an example 'tee' implementation:

File.open(ARGV[0], 'w') do |file|
  ARGV.clear

  ARGF.each do |line|
    puts line
    file.write(line)
  end
end

What is the preferred/idiomatic way to insert into a map?

In short, [] operator is more efficient for updating values because it involves calling default constructor of the value type and then assigning it a new value, while insert() is more efficient for adding values.

The quoted snippet from Effective STL: 50 Specific Ways to Improve Your Use of the Standard Template Library by Scott Meyers, Item 24 might help.

template<typename MapType, typename KeyArgType, typename ValueArgType>
typename MapType::iterator
insertKeyAndValue(MapType& m, const KeyArgType&k, const ValueArgType& v)
{
    typename MapType::iterator lb = m.lower_bound(k);

    if (lb != m.end() && !(m.key_comp()(k, lb->first))) {
        lb->second = v;
        return lb;
    } else {
        typedef typename MapType::value_type MVT;
        return m.insert(lb, MVT(k, v));
    }
}

You may decide to choose a generic-programming-free version of this, but the point is that I find this paradigm (differentiating 'add' and 'update') extremely useful.

RESTful call in Java

Most Easy Solution will be using Apache http client library. refer following sample code.. this code uses basic security for authenticating.

Add following Dependency.

<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.4</version>
</dependency>
CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
Credentials credentials = new UsernamePasswordCredentials("username", "password");
credentialsProvider.setCredentials(AuthScope.ANY, credentials);
HttpClient client = HttpClientBuilder.create().setDefaultCredentialsProvider(credentialsProvider).build();
HttpPost request = new HttpPost("https://api.plivo.com/v1/Account/MAYNJ3OT/Message/");HttpResponse response = client.execute(request);
    // Get the response
    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    String line = "";
    while ((line = rd.readLine()) != null) {    
    textView = textView + line;
    }
    System.out.println(textView);

Is it possible to create static classes in PHP (like in C#)?

You can have static classes in PHP but they don't call the constructor automatically (if you try and call self::__construct() you'll get an error).

Therefore you'd have to create an initialize() function and call it in each method:

<?php

class Hello
{
    private static $greeting = 'Hello';
    private static $initialized = false;

    private static function initialize()
    {
        if (self::$initialized)
            return;

        self::$greeting .= ' There!';
        self::$initialized = true;
    }

    public static function greet()
    {
        self::initialize();
        echo self::$greeting;
    }
}

Hello::greet(); // Hello There!


?>

SVN Error: Commit blocked by pre-commit hook (exit code 1) with output: Error: n/a (6)

SOLUTION for WORDPRESS PLUGINS:

I think, get_option() returns FALSE (instead of EMPTY). So, check your plugin. Instead of:

if (empty(get_option('smth')))

there should be:

if (!get_option('smth'))

How to continue the code on the next line in VBA

In VBA (and VB.NET) the line terminator (carriage return) is used to signal the end of a statement. To break long statements into several lines, you need to

Use the line-continuation character, which is an underscore (_), at the point at which you want the line to break. The underscore must be immediately preceded by a space and immediately followed by a line terminator (carriage return).

(From How to: Break and Combine Statements in Code)

In other words: Whenever the interpreter encounters the sequence <space>_<line terminator>, it is ignored and parsing continues on the next line. Note, that even when ignored, the line continuation still acts as a token separator, so it cannot be used in the middle of a variable name, for example. You also cannot continue a comment by using a line-continuation character.

To break the statement in your question into several lines you could do the following:

U_matrix(i, j, n + 1) = _
     k * b_xyt(xi, yi, tn) / (4 * hx * hy) * U_matrix(i + 1, j + 1, n) + _
     (k * (a_xyt(xi, yi, tn) / hx ^ 2 + d_xyt(xi, yi, tn) / (2 * hx)))

(Leading whitespaces are ignored.)

What are .dex files in Android?

.dex file

Compiled Android application code file.

Android programs are compiled into .dex (Dalvik Executable) files, which are in turn zipped into a single .apk file on the device. .dex files can be created automatically by Android, by translating the compiled applications written in the Java programming language.

Datatables on-the-fly resizing

$(document).ready(function() {
    $('a[data-toggle="tab"]').on( 'shown.bs.tab', function (e) {
        // var target = $(e.target).attr("href"); // activated tab
        // alert (target);
        $($.fn.dataTable.tables( true ) ).css('width', '100%');
        $($.fn.dataTable.tables( true ) ).DataTable().columns.adjust().draw();
    } ); 
});

It works for me, with "autoWidth": false,

C++ terminate called without an active exception

year, the thread must be join(). when the main exit

ImportError: No module named apiclient.discovery

It only worked with me when I used sudo:

sudo pip install --upgrade google-api-python-client

jQuery click events not working in iOS

There is an issue with iOS not registering click/touch events bound to elements added after DOM loads.

While PPK has this advice: http://www.quirksmode.org/blog/archives/2010/09/click_event_del.html

I've found this the easy fix, simply add this to the css:

cursor: pointer;

Print a div using javascript in angularJS single page application

Two conditional functions are needed: one for Google Chrome, and a second for the remaining browsers.

$scope.printDiv = function (divName) {

    var printContents = document.getElementById(divName).innerHTML; 

    if (navigator.userAgent.toLowerCase().indexOf('chrome') > -1) {
        var popupWin = window.open('', '_blank', 'width=600,height=600,scrollbars=no,menubar=no,toolbar=no,location=no,status=no,titlebar=no');
        popupWin.window.focus();
        popupWin.document.write('<!DOCTYPE html><html><head>' +
            '<link rel="stylesheet" type="text/css" href="style.css" />' +
            '</head><body onload="window.print()"><div class="reward-body">' + printContents + '</div></body></html>');
        popupWin.onbeforeunload = function (event) {
            popupWin.close();
            return '.\n';
        };
        popupWin.onabort = function (event) {
            popupWin.document.close();
            popupWin.close();
        }
    } else {
        var popupWin = window.open('', '_blank', 'width=800,height=600');
        popupWin.document.open();
        popupWin.document.write('<html><head><link rel="stylesheet" type="text/css" href="style.css" /></head><body onload="window.print()">' + printContents + '</body></html>');
        popupWin.document.close();
    }
    popupWin.document.close();

    return true;
}

Android : Capturing HTTP Requests with non-rooted android device

You can use fiddler as webdebugger http://www.telerik.com/fiddler/web-debugging

Fiddler is a debugging tool from telerik software, which helps you to intercept every request that is initiated from your machine.

byte[] to hex string

I thought I should provide an answer. From my test this method is the fastest

public static class Helper
{
    public static string[] HexTbl = Enumerable.Range(0, 256).Select(v => v.ToString("X2")).ToArray();
    public static string ToHex(this IEnumerable<byte> array)
    {
        StringBuilder s = new StringBuilder();
        foreach (var v in array)
            s.Append(HexTbl[v]);
        return s.ToString();
    }
    public static string ToHex(this byte[] array)
    {
        StringBuilder s = new StringBuilder(array.Length*2);
        foreach (var v in array)
            s.Append(HexTbl[v]);
        return s.ToString();
    }
}

Sum values from an array of key-value pairs in JavaScript

I would use reduce

var myData = new Array(['2013-01-22', 0], ['2013-01-29', 0], ['2013-02-05', 0], ['2013-02-12', 0], ['2013-02-19', 0], ['2013-02-26', 0], ['2013-03-05', 0], ['2013-03-12', 0], ['2013-03-19', 0], ['2013-03-26', 0], ['2013-04-02', 21], ['2013-04-09', 2]);

var sum = myData.reduce(function(a, b) {
    return a + b[1];
}, 0);

$("#result").text(sum);

Available on jsfiddle

Run php script as daemon process

If you can - grab a copy of Advanced Programming in the UNIX Environment. The entire chapter 13 is devoted to daemon programming. Examples are in C, but all the function you need have wrappers in PHP (basically the pcntl and posix extensions).

In a few words - writing a daemon (this is posible only on *nix based OS-es - Windows uses services) is like this:

  1. Call umask(0) to prevent permission issues.
  2. fork() and have the parent exit.
  3. Call setsid().
  4. Setup signal processing of SIGHUP (usually this is ignored or used to signal the daemon to reload its configuration) and SIGTERM (to tell the process to exit gracefully).
  5. fork() again and have the parent exit.
  6. Change the current working dir with chdir().
  7. fclose() stdin, stdout and stderr and don't write to them. The corrrect way is to redirect those to either /dev/null or a file, but I couldn't find a way to do it in PHP. It is possible when you launch the daemon to redirect them using the shell (you'll have to find out yourself how to do that, I don't know :).
  8. Do your work!

Also, since you are using PHP, be careful for cyclic references, since the PHP garbage collector, prior to PHP 5.3, has no way of collecting those references and the process will memory leak, until it eventually crashes.

How to correctly catch change/focusOut event on text input in React.js?

You'd need to be careful as onBlur has some caveats in IE11 (How to use relatedTarget (or equivalent) in IE?, https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/relatedTarget).

There is, however, no way to use onFocusOut in React as far as I can tell. See the issue on their github https://github.com/facebook/react/issues/6410 if you need more information.

Unable to connect to SQL Express "Error: 26-Error Locating Server/Instance Specified)

The active firewall on the server might be causing this. You can try to (temporarily) turn it off and see if it resolves the issue.

If it is indeed caused by the firewall, you should allegedly be able to resolve it by adding an inbound rule for TCP port 1433 set to allowed, but I personally haven't been able to connect this way.

Understanding unique keys for array children in React.js

This may or not help someone, but it might be a quick reference. This is also similar to all the answers presented above.

I have a lot of locations that generate list using the structure below:

return (
    {myList.map(item => (
       <>
          <div class="some class"> 
             {item.someProperty} 
              ....
          </div>
       </>
     )}
 )
         

After a little trial and error (and some frustrations), adding a key property to the outermost block resolved it. Also, note that the <> tag is now replaced with the <div> tag now.

return (
  
    {myList.map((item, index) => (
       <div key={index}>
          <div class="some class"> 
             {item.someProperty} 
              ....
          </div>
       </div>
     )}
 )

Of course, I've been naively using the iterating index (index) to populate the key value in the above example. Ideally, you'd use something which is unique to the list item.

Carriage Return\Line feed in Java

bw.newLine(); cannot ensure compatibility with all systems.

If you are sure it is going to be opened in windows, you can format it to windows newline.

If you are already using native unix commands, try unix2dos and convert teh already generated file to windows format and then send the mail.

If you are not using unix commands and prefer to do it in java, use ``bw.write("\r\n")` and if it does not complicate your program, have a method that finds out the operating system and writes the appropriate newline.

Convert pandas dataframe to NumPy array

I would just chain the DataFrame.reset_index() and DataFrame.values functions to get the Numpy representation of the dataframe, including the index:

In [8]: df
Out[8]: 
          A         B         C
0 -0.982726  0.150726  0.691625
1  0.617297 -0.471879  0.505547
2  0.417123 -1.356803 -1.013499
3 -0.166363 -0.957758  1.178659
4 -0.164103  0.074516 -0.674325
5 -0.340169 -0.293698  1.231791
6 -1.062825  0.556273  1.508058
7  0.959610  0.247539  0.091333

[8 rows x 3 columns]

In [9]: df.reset_index().values
Out[9]:
array([[ 0.        , -0.98272574,  0.150726  ,  0.69162512],
       [ 1.        ,  0.61729734, -0.47187926,  0.50554728],
       [ 2.        ,  0.4171228 , -1.35680324, -1.01349922],
       [ 3.        , -0.16636303, -0.95775849,  1.17865945],
       [ 4.        , -0.16410334,  0.0745164 , -0.67432474],
       [ 5.        , -0.34016865, -0.29369841,  1.23179064],
       [ 6.        , -1.06282542,  0.55627285,  1.50805754],
       [ 7.        ,  0.95961001,  0.24753911,  0.09133339]])

To get the dtypes we'd need to transform this ndarray into a structured array using view:

In [10]: df.reset_index().values.ravel().view(dtype=[('index', int), ('A', float), ('B', float), ('C', float)])
Out[10]:
array([( 0, -0.98272574,  0.150726  ,  0.69162512),
       ( 1,  0.61729734, -0.47187926,  0.50554728),
       ( 2,  0.4171228 , -1.35680324, -1.01349922),
       ( 3, -0.16636303, -0.95775849,  1.17865945),
       ( 4, -0.16410334,  0.0745164 , -0.67432474),
       ( 5, -0.34016865, -0.29369841,  1.23179064),
       ( 6, -1.06282542,  0.55627285,  1.50805754),
       ( 7,  0.95961001,  0.24753911,  0.09133339),
       dtype=[('index', '<i8'), ('A', '<f8'), ('B', '<f8'), ('C', '<f8')])

Conditionally Remove Dataframe Rows with R

Use the which function:

A <- c('a','a','b','b','b')
B <- c(1,0,1,1,0)
d <- data.frame(A, B)

r <- with(d, which(B==0, arr.ind=TRUE))
newd <- d[-r, ]

How to perform grep operation on all files in a directory?

In Linux, I normally use this command to recursively grep for a particular text within a dir

grep -rni "string" *

where,

r = recursive i.e, search subdirectories within the current directory
n = to print the line numbers to stdout
i = case insensitive search

Open file by its full path in C++

For those who are getting the path dynamicly... e.g. drag&drop:

Some main constructions get drag&dropped file with double quotes like:

"C:\MyPath\MyFile.txt"

Quick and nice solution is to use this function to remove chars from string:

void removeCharsFromString( string &str, char* charsToRemove ) {
   for ( unsigned int i = 0; i < strlen(charsToRemove); ++i ) {
      str.erase( remove(str.begin(), str.end(), charsToRemove[i]), str.end() );
   }
} 

string myAbsolutepath; //fill with your absolute path
removeCharsFromString( myAbsolutepath, "\"" );

myAbsolutepath now contains just C:\MyPath\MyFile.txt

The function needs these libraries: <iostream> <algorithm> <cstring>.
The function was based on this answer.

Working Fiddle: http://ideone.com/XOROjq

Can a table row expand and close?

You could do it like this:

HTML

<table>
    <tr>
        <td>Cell 1</td>
        <td>Cell 2</td>
        <td>Cell 3</td>
        <td>Cell 4</td>
        <td><a href="#" id="show_1">Show Extra</a></td>
    </tr>
    <tr>
        <td colspan="5">
            <div id="extra_1" style="display: none;">
                <br>hidden row
                <br>hidden row
                <br>hidden row
            </div>
        </td>
    </tr>
</table>

jQuery

$("a[id^=show_]").click(function(event) {
    $("#extra_" + $(this).attr('id').substr(5)).slideToggle("slow");
    event.preventDefault();
});

See a demo on JSFiddle

how to get yesterday's date in C#

Use DateTime.AddDays() method with value of -1

var yesterday = DateTime.Today.AddDays(-1);

That will give you : {6/28/2012 12:00:00 AM}

You can also use

DateTime.Now.AddDays(-1)

That will give you previous date with the current time e.g. {6/28/2012 10:30:32 AM}

Create local maven repository

Set up a simple repository using a web server with its default configuration. The key is the directory structure. The documentation does not mention it explicitly, but it is the same structure as a local repository.

To set up an internal repository just requires that you have a place to put it, and then start copying required artifacts there using the same layout as in a remote repository such as repo.maven.apache.org. Source

Add a file to your repository like this:

mvn install:install-file \
  -Dfile=YOUR_JAR.jar -DgroupId=YOUR_GROUP_ID 
  -DartifactId=YOUR_ARTIFACT_ID -Dversion=YOUR_VERSION \
  -Dpackaging=jar \
  -DlocalRepositoryPath=/var/www/html/mavenRepository

If your domain is example.com and the root directory of the web server is located at /var/www/html/, then maven can find "YOUR_JAR.jar" if configured with <url>http://example.com/mavenRepository</url>.

How to Call a JS function using OnClick event

You could use addEventListener to add as many listeners as you want.

  document.getElementById("Save").addEventListener('click',function ()
    {
     alert("hello");
     //validation code to see State field is mandatory.  
    }  ); 

Also add script tag after the element to make sure Save element is loaded at the time when script runs

Rather than moving script tag you could call it when dom is loaded. Then you should place your code inside the

document.addEventListener('DOMContentLoaded', function() {
    document.getElementById("Save").addEventListener('click',function ()
    {
     alert("hello");
     //validation code to see State field is mandatory.  
    }  ); 
});

example

Get name of current class?

You can access it by the class' private attributes:

cls_name = self.__class__.__name__

EDIT:

As said by Ned Batcheler, this wouldn't work in the class body, but it would in a method.

Error in plot.window(...) : need finite 'xlim' values

The problem is that you're (probably) trying to plot a vector that consists exclusively of missing (NA) values. Here's an example:

> x=rep(NA,100)
> y=rnorm(100)
> plot(x,y)
Error in plot.window(...) : need finite 'xlim' values
In addition: Warning messages:
1: In min(x) : no non-missing arguments to min; returning Inf
2: In max(x) : no non-missing arguments to max; returning -Inf

In your example this means that in your line plot(costs,pseudor2,type="l"), costs is completely NA. You have to figure out why this is, but that's the explanation of your error.


From comments:

Scott C Wilson: Another possible cause of this message (not in this case, but in others) is attempting to use character values as X or Y data. You can use the class function to check your x and Y values to be sure if you think this might be your issue.

stevec: Here is a quick and easy solution to that problem (basically wrap x in as.factor(x))

Create a List of primitive int?

In Java the type of any variable is either a primitive type or a reference type. Generic type arguments must be reference types. Since primitives do not extend Object they cannot be used as generic type arguments for a parametrized type.

Instead use the Integer class which is a wrapper for int:

List<Integer> list = new ArrayList<Integer>();

If your using Java 7 you can simplify this declaration using the diamond operator:

List<Integer> list = new ArrayList<>();

With autoboxing in Java the primitive type int will become an Integer when necessary.

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes.

So the following is valid:

int myInt = 1;
List<Integer> list = new ArrayList<Integer>();
list.add(myInt);

System.out.println(list.get(0)); //prints 1

Eclipse says: “Workspace in use or cannot be created, chose a different one.” How do I unlock a workspace?

I don't know what's the wrong but I solved by creating a directory directly in c drive(c:\dev) instead of from my home folder (c:\users\me\dev). But I don't have to thinks about it. In my case, it is fresh eclipse unziped instance. I am not able to see .matadata folder in eclipse folder. By God grace, I solved.

How can I commit files with git?

in standart Vi editor in this situation you should

  1. press Esc
  2. type ":wq" (without quotes)
  3. Press Enter

Using the HTML5 "required" attribute for a group of checkboxes?

Really simple way to verify if at least one checkbox is checked:

function isAtLeastOneChecked(name) {
    let checkboxes = Array.from(document.getElementsByName(name));
    return checkboxes.some(e => e.checked);
}

Then you can implement whatever logic you want to display an error.

Where can I find the .apk file on my device, when I download any app and install?

You can do that I believe. It needs root permission. If you want to know where your apk files are stored, open a emulator and then go to

DDMS>File Explorer-> you can see a directory by name "data" -> Click on it and you will see a "app" folder.

Your apks are stored there. In fact just copying a apk directly to the folder works for me with emulators.

How to improve performance of ngRepeat over a huge dataset (angular.js)?

The hottest - and arguably most scalable - approach to overcoming these challenges with large datasets is embodied by the approach of Ionic's collectionRepeat directive and of other implementations like it. A fancy term for this is 'occlusion culling', but you can sum it up as: don't just limit the count of rendered DOM elements to an arbitrary (but still high) paginated number like 50, 100, 500... instead, limit only to as many elements as the user can see.

If you do something like what's commonly known as "infinite scrolling", you're reducing the initial DOM count somewhat, but it bloats quickly after a couple refreshes, because all those new elements are just tacked on at the bottom. Scrolling comes to a crawl, because scrolling is all about element count. There's nothing infinite about it.

Whereas, the collectionRepeat approach is to use only as many elements as will fit in viewport, and then recycle them. As one element rotates out of view, it's detached from the render tree, refilled with data for a new item in the list, then reattached to the render tree at the other end of the list. This is the fastest way known to man to get new information in and out of the DOM, making use of a limited set of existing elements, rather than the traditional cycle of create/destroy... create/destroy. Using this approach, you can truly implement an infinite scroll.

Note that you don't have to use Ionic to use/hack/adapt collectionRepeat, or any other tool like it. That's why they call it open-source. :-) (That said, the Ionic team is doing some pretty ingenious things, worthy of your attention.)


There's at least one excellent example of doing something very similar in React. Only instead of recycling the elements with updated content, you're simply choosing not to render anything in the tree that's not in view. It's blazing fast on 5000 items, although their very simple POC implementation allows a bit of flicker...


Also... to echo some of the other posts, using track by is seriously helpful, even with smaller datasets. Consider it mandatory.

cast or convert a float to nvarchar?

For anyone willing to try a different method, they can use this:

select FORMAT([Column_Name], '') from YourTable

This will easily change any float value to nvarchar.

How to return a value from __init__ in Python?

__init__ doesn't return anything and should always return None.

SQL MERGE statement to update data

Update energydata set energydata.kWh = temp.kWh 
where energydata.webmeterID = (select webmeterID from temp_energydata as temp) 

How do you give iframe 100% height

You can do it with CSS:

<iframe style="position: absolute; height: 100%; border: none"></iframe>

Be aware that this will by default place it in the upper-left corner of the page, but I guess that is what you want to achieve. You can position with the left,right, top and bottom CSS properties.

How to add a form load event (currently not working)

Three ways you can do this - from the form designer, select the form, and where you normally see the list of properties, just above it there should be a little lightning symbol - this shows you all the events of the form. Find the form load event in the list, and you should be able to pick ProgramViwer_Load from the dropdown.

A second way to do it is programmatically - somewhere (constructor maybe) you'd need to add it, something like: ProgramViwer.Load += new EventHandler(ProgramViwer_Load);

A third way using the designer (probably the quickest) - when you create a new form, double click on the middle of it on it in design mode. It'll create a Form load event for you, hook it in, and take you to the event handler code. Then you can just add your two lines and you're good to go!

How do you access the matched groups in a JavaScript regular expression?

You don't really need an explicit loop to parse multiple matches — pass a replacement function as the second argument as described in: String.prototype.replace(regex, func):

_x000D_
_x000D_
var str = "Our chief weapon is {1}, {0} and {2}!"; _x000D_
var params= ['surprise', 'fear', 'ruthless efficiency'];_x000D_
var patt = /{([^}]+)}/g;_x000D_
_x000D_
str=str.replace(patt, function(m0, m1, position){return params[parseInt(m1)];});_x000D_
_x000D_
document.write(str);
_x000D_
_x000D_
_x000D_

The m0 argument represents the full matched substring {0}, {1}, etc. m1 represents the first matching group, i.e. the part enclosed in brackets in the regex which is 0 for the first match. And position is the starting index within the string where the matching group was found — unused in this case.

HTTP Status 504

Suppose access a proxy server A(eg. nginx), and the server A forwards the request to another server B(eg. tomcat).

If this process continues for a long time (more than the proxy server read timeout setting), A still did not get a completed response of B. It happens.

for nginx, You can configure the proxy_read_timeout(in location) property to solve his.But this is usually not a good idea, if you set the value too high. This may hide the real error.You'd better improve the design to really solve this problem.

How to convert hex string to Java string?

Using Hex in Apache Commons:

String hexString = "fd00000aa8660b5b010006acdc0100000101000100010000";    
byte[] bytes = Hex.decodeHex(hexString.toCharArray());
System.out.println(new String(bytes, "UTF-8"));

#1273 – Unknown collation: ‘utf8mb4_unicode_520_ci’

In my case it turns out my
new server was running MySQL 5.5,
old server was running MySQL 5.6.
So I got this error when trying to import the .sql file I'd exported from my old server.

MySQL 5.5 does not support utf8mb4_unicode_520_ci, but
MySQL 5.6 does.

Updating to MySQL 5.6 on the new server solved collation the error !

If you want to retain MySQL 5.5, you can:
- make a copy of your exported .sql file
- replace instances of utf8mb4unicode520_ci and utf8mb4_unicode_520_ci
...with utf8mb4_unicode_ci
- import your updated .sql file.

How do I deserialize a JSON string into an NSDictionary? (For iOS 5+)

Using Abizern code for swift 2.2

let objectData = responseString!.dataUsingEncoding(NSUTF8StringEncoding)
let json = try NSJSONSerialization.JSONObjectWithData(objectData!, options: NSJSONReadingOptions.MutableContainers)

CSS Always On Top

Ensure position is on your element and set the z-index to a value higher than the elements you want to cover.

element {
    position: fixed;
    z-index: 999;
}

div {
    position: relative;
    z-index: 99;
}

It will probably require some more work than that but it's a start since you didn't post any code.

What Regex would capture everything from ' mark to the end of a line?

The appropriate regex would be the ' char followed by any number of any chars [including zero chars] ending with an end of string/line token:

'.*$

And if you wanted to capture everything after the ' char but not include it in the output, you would use:

(?<=').*$

This basically says give me all characters that follow the ' char until the end of the line.

Edit: It has been noted that $ is implicit when using .* and therefore not strictly required, therefore the pattern:

'.* 

is technically correct, however it is clearer to be specific and avoid confusion for later code maintenance, hence my use of the $. It is my belief that it is always better to declare explicit behaviour than rely on implicit behaviour in situations where clarity could be questioned.

VBA equivalent to Excel's mod function

But if you just want to tell the difference between an odd iteration and an even iteration, this works just fine:

If i Mod 2 > 0 then 'this is an odd 
   'Do Something
Else 'it is even
   'Do Something Else
End If

Android Activity as a dialog

Set the theme in your android manifest file.

<activity android:name=".LoginActivity"
            android:theme="@android:style/Theme.Dialog"/>

And set the dialog state on touch to finish.

this.setFinishOnTouchOutside(false);

How to get DateTime.Now() in YYYY-MM-DDThh:mm:ssTZD format using C#

Use the zzz format specifier to get the timezone offset as hours and minutes. You also want to use the HH format specifier to get the hours in 24 hour format.

DateTime.Now.ToString("yyyy-MM-ddTHH:mm:sszzz")

Result:

2011-08-09T23:49:58+02:00

Some culture settings uses periods instead of colons for time, so you might want to use literal colons instead of time separators:

DateTime.Now.ToString("yyyy-MM-ddTHH':'mm':'sszzz")

Custom Date and Time Format Strings

How to call function that takes an argument in a Django template?

By design, Django templates cannot call into arbitrary Python code. This is a security and safety feature for environments where designers write templates, and it also prevents business logic migrating into templates.

If you want to do this, you can switch to using Jinja2 templates (http://jinja.pocoo.org/docs/), or any other templating system you like that supports this. No other part of django will be affected by the templates you use, because it is intentionally a one-way process. You could even use many different template systems in the same project if you wanted.

How can I do an OrderBy with a dynamic string parameter?

I did so:

using System.Linq.Expressions;

namespace System.Linq
{
    public static class LinqExtensions
    {

        public static IOrderedQueryable<TSource> OrderBy<TSource>(this IQueryable<TSource> source, string field, string dir = "asc")
        {
            // parametro => expressão
            var parametro = Expression.Parameter(typeof(TSource), "r");
            var expressao = Expression.Property(parametro, field);
            var lambda = Expression.Lambda(expressao, parametro); // r => r.AlgumaCoisa
            var tipo = typeof(TSource).GetProperty(field).PropertyType;

            var nome = "OrderBy";
            if (string.Equals(dir, "desc", StringComparison.InvariantCultureIgnoreCase))
            {
                nome = "OrderByDescending";
            }
            var metodo = typeof(Queryable).GetMethods().First(m => m.Name == nome && m.GetParameters().Length == 2);
            var metodoGenerico = metodo.MakeGenericMethod(new[] { typeof(TSource), tipo });
            return metodoGenerico.Invoke(source, new object[] { source, lambda }) as IOrderedQueryable<TSource>;

        }

        public static IOrderedQueryable<TSource> ThenBy<TSource>(this IOrderedQueryable<TSource> source, string field, string dir = "asc")
        {
            var parametro = Expression.Parameter(typeof(TSource), "r");
            var expressao = Expression.Property(parametro, field);
            var lambda = Expression.Lambda<Func<TSource, string>>(expressao, parametro); // r => r.AlgumaCoisa
            var tipo = typeof(TSource).GetProperty(field).PropertyType;

            var nome = "ThenBy";
            if (string.Equals(dir, "desc", StringComparison.InvariantCultureIgnoreCase))
            {
                nome = "ThenByDescending";
            }

            var metodo = typeof(Queryable).GetMethods().First(m => m.Name == nome && m.GetParameters().Length == 2);
            var metodoGenerico = metodo.MakeGenericMethod(new[] { typeof(TSource), tipo });
            return metodoGenerico.Invoke(source, new object[] { source, lambda }) as IOrderedQueryable<TSource>;
        }

    }
}

Use :

example.OrderBy("Nome", "desc").ThenBy("other")

Work like:

example.OrderByDescending(r => r.Nome).ThenBy(r => r.other)

What is the difference between 0.0.0.0, 127.0.0.1 and localhost?

127.0.0.1 is normally the IP address assigned to the "loopback" or local-only interface. This is a "fake" network adapter that can only communicate within the same host. It's often used when you want a network-capable application to only serve clients on the same host. A process that is listening on 127.0.0.1 for connections will only receive local connections on that socket.

"localhost" is normally the hostname for the 127.0.0.1 IP address. It's usually set in /etc/hosts (or the Windows equivalent named "hosts" somewhere under %WINDIR%). You can use it just like any other hostname - try "ping localhost" to see how it resolves to 127.0.0.1.

0.0.0.0 has a couple of different meanings, but in this context, when a server is told to listen on 0.0.0.0 that means "listen on every available network interface". The loopback adapter with IP address 127.0.0.1 from the perspective of the server process looks just like any other network adapter on the machine, so a server told to listen on 0.0.0.0 will accept connections on that interface too.

That hopefully answers the IP side of your question. I'm not familiar with Jekyll or Vagrant, but I'm guessing that your port forwarding 8080 => 4000 is somehow bound to a particular network adapter, so it isn't in the path when you connect locally to 127.0.0.1

Using "word-wrap: break-word" within a table

table-layout: fixed will get force the cells to fit the table (and not the other way around), e.g.:

<table style="border: 1px solid black; width: 100%; word-wrap:break-word;
              table-layout: fixed;">
  <tr>
    <td>
        aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
        bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
    </td>
  </tr>
</table>

Limit number of characters allowed in form input text field

<input type="text" maxlength="5">

the maximum amount of letters that can be in the input is 5.

OpenCV - DLL missing, but it's not?

Just for your information,after add the "PATH",for my win7 i need to reboot it to get it work.

Get program path in VB.NET?

I use:

Imports System.IO
Dim strPath as String=Directory.GetCurrentDirectory

Using LINQ to concatenate strings

There are various alternative answers at this previous question - which admittedly was targeting an integer array as the source, but received generalised answers.

How to use the 'replace' feature for custom AngularJS directives?

When you have replace: true you get the following piece of DOM:

<div ng-controller="Ctrl" class="ng-scope">
    <div class="ng-binding">hello</div>
</div>

whereas, with replace: false you get this:

<div ng-controller="Ctrl" class="ng-scope">
    <my-dir>
        <div class="ng-binding">hello</div>
    </my-dir>
</div>

So the replace property in directives refer to whether the element to which the directive is being applied (<my-dir> in that case) should remain (replace: false) and the directive's template should be appended as its child,

OR

the element to which the directive is being applied should be replaced (replace: true) by the directive's template.

In both cases the element's (to which the directive is being applied) children will be lost. If you wanted to perserve the element's original content/children you would have to translude it. The following directive would do it:

.directive('myDir', function() {
    return {
        restrict: 'E',
        replace: false,
        transclude: true,
        template: '<div>{{title}}<div ng-transclude></div></div>'
    };
});

In that case if in the directive's template you have an element (or elements) with attribute ng-transclude, its content will be replaced by the element's (to which the directive is being applied) original content.

See example of translusion http://plnkr.co/edit/2DJQydBjgwj9vExLn3Ik?p=preview

See this to read more about translusion.

Get the client IP address using PHP

    $ipaddress = '';
    if ($_SERVER['HTTP_CLIENT_IP'] != '127.0.0.1')
        $ipaddress = $_SERVER['HTTP_CLIENT_IP'];
    else if ($_SERVER['HTTP_X_FORWARDED_FOR'] != '127.0.0.1')
        $ipaddress = $_SERVER['HTTP_X_FORWARDED_FOR'];
    else if ($_SERVER['HTTP_X_FORWARDED'] != '127.0.0.1')
        $ipaddress = $_SERVER['HTTP_X_FORWARDED'];
    else if ($_SERVER['HTTP_FORWARDED_FOR'] != '127.0.0.1')
        $ipaddress = $_SERVER['HTTP_FORWARDED_FOR'];
    else if ($_SERVER['HTTP_FORWARDED'] != '127.0.0.1')
        $ipaddress = $_SERVER['HTTP_FORWARDED'];
    else if ($_SERVER['REMOTE_ADDR'] != '127.0.0.1')
        $ipaddress = $_SERVER['REMOTE_ADDR'];
    else
        $ipaddress = 'UNKNOWN';

$this->session->set_flashdata() and then $this->session->flashdata() doesn't work in codeigniter

flash message after redirect will available in controller not in view. to show in view get in controller's action and pass it view

JSON serialization/deserialization in ASP.Net Core

You can use Newtonsoft.Json, it's a dependency of Microsoft.AspNet.Mvc.ModelBinding which is a dependency of Microsoft.AspNet.Mvc. So, you don't need to add a dependency in your project.json.

#using Newtonsoft.Json
....
JsonConvert.DeserializeObject(json);

Note, using a WebAPI controller you don't need to deal with JSON.

UPDATE ASP.Net Core 3.0

Json.NET has been removed from the ASP.NET Core 3.0 shared framework.

You can use the new JSON serializer layers on top of the high-performance Utf8JsonReader and Utf8JsonWriter. It deserializes objects from JSON and serializes objects to JSON. Memory allocations are kept minimal and includes support for reading and writing JSON with Stream asynchronously.

To get started, use the JsonSerializer class in the System.Text.Json.Serialization namespace. See the documentation for information and samples.

To use Json.NET in an ASP.NET Core 3.0 project:

    services.AddMvc()
        .AddNewtonsoftJson();

Read Json.NET support in Migrate from ASP.NET Core 2.2 to 3.0 Preview 2 for more information.

Running .sh scripts in Git Bash

I had a similar problem, but I was getting an error message

cannot execute binary file

I discovered that the filename contained non-ASCII characters. When those were fixed, the script ran fine with ./script.sh.

How to remove the URL from the printing page?

I have a trick to remove it from the print page in Firefox. Use this:

<html moznomarginboxes mozdisallowselectionprint>

In the html tag you have to use moznomarginboxes mozdisallowselectionprint. I am sure it will help you a lot.

How to add composite primary key to table

If using Sql Server Management Studio Designer just select both rows (Shift+Click) and Set Primary Key.

enter image description here

How to convert JSON object to an Typescript array?

You have a JSON object that contains an Array. You need to access the array results. Change your code to:

this.data = res.json().results

Convert JSON to Map

With google's Gson 2.7 (probably earlier versions too, but I tested 2.7) it's as simple as:

Map map = gson.fromJson(json, Map.class);

Which returns a Map of type class com.google.gson.internal.LinkedTreeMap and works recursively on nested objects.

ASP.NET MVC How to pass JSON object from View to Controller as Parameter

A different take with a simple jQuery plugin

Even though answers to this question are long overdue, but I'm still posting a nice solution that I came with some time ago and makes it really simple to send complex JSON to Asp.net MVC controller actions so they are model bound to whatever strong type parameters.

This plugin supports dates just as well, so they get converted to their DateTime counterpart without a problem.

You can find all the details in my blog post where I examine the problem and provide code necessary to accomplish this.

All you have to do is to use this plugin on the client side. An Ajax request would look like this:

$.ajax({
    type: "POST",
    url: "SomeURL",
    data: $.toDictionary(yourComplexJSONobject),
    success: function() { ... },
    error: function() { ... }
});

But this is just part of the whole problem. Now we are able to post complex JSON back to server, but since it will be model bound to a complex type that may have validation attributes on properties things may fail at that point. I've got a solution for it as well. My solution takes advantage of jQuery Ajax functionality where results can be successful or erroneous (just as shown in the upper code). So when validation would fail, error function would get called as it's supposed to be.

How can I specify system properties in Tomcat configuration on startup?

Generally you shouldn't rely on system properties to configure a webapp - they may be used to configure the container (e.g. Tomcat) but not an application running inside tomcat.

cliff.meyers has already mentioned the way you should rather use for your webapplication. That's the standard way, that also fits your question of being configurable through context.xml or server.xml means.

That said, should you really need system properties or other jvm options (like max memory settings) in tomcat, you should create a file named "bin/setenv.sh" or "bin/setenv.bat". These files do not exist in the standard archive that you download, but if they are present, the content is executed during startup (if you start tomcat via startup.sh/startup.bat). This is a nice way to separate your own settings from the standard tomcat settings and makes updates so much easier. No need to tweak startup.sh or catalina.sh.

(If you execute tomcat as windows servive, you usually use tomcat5w.exe, tomcat6w.exe etc. to configure the registry settings for the service.)

EDIT: Also, another possibility is to go for JNDI Resources.

How to check if a network port is open on linux?

Here's a fast multi-threaded port scanner:

from time import sleep
import socket, ipaddress, threading

max_threads = 50
final = {}
def check_port(ip, port):
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # TCP
        #sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # UDP
        socket.setdefaulttimeout(2.0) # seconds (float)
        result = sock.connect_ex((ip,port))
        if result == 0:
            # print ("Port is open")
            final[ip] = "OPEN"
        else:
            # print ("Port is closed/filtered")
            final[ip] = "CLOSED"
        sock.close()
    except:
        pass
port = 80
for ip in ipaddress.IPv4Network('192.168.1.0/24'): 
    threading.Thread(target=check_port, args=[str(ip), port]).start()
    #sleep(0.1)

# limit the number of threads.
while threading.active_count() > max_threads :
    sleep(1)

print(final)

Live Demo

How do I auto-hide placeholder text upon focus using css or jquery?

$("input[placeholder]").each(function () {
    $(this).attr("data-placeholder", this.placeholder);

    $(this).bind("focus", function () {
        this.placeholder = '';
    });
    $(this).bind("blur", function () {
        this.placeholder = $(this).attr("data-placeholder");
    });
});

How to set a parameter in a HttpServletRequest?

Sorry, but why not use the following construction:

request.getParameterMap().put(parameterName, new String[] {parameterValue});

How can I clear the Scanner buffer in Java?

Use the following command:

in.nextLine();

right after

System.out.println("Invalid input. Please Try Again.");
System.out.println();

or after the following curly bracket (where your comment regarding it, is).

This command advances the scanner to the next line (when reading from a file or string, this simply reads the next line), thus essentially flushing it, in this case. It clears the buffer and readies the scanner for a new input. It can, preferably, be used for clearing the current buffer when a user has entered an invalid input (such as a letter when asked for a number).

Documentation of the method can be found here: http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#nextLine()

Hope this helps!

Eclipse - Installing a new JRE (Java SE 8 1.8.0)

You can have many java versions in your system.

I think you should add the java 8 in yours JREs installed or edit.

Take a look my screen:

enter image description here

If you click in edit (check your java 8 path):

enter image description here

jQuery - simple input validation - "empty" and "not empty"

    jQuery("#input").live('change', function() {
        // since we check more than once against the value, place it in a var.
        var inputvalue = $("#input").attr("value");

        // if it's value **IS NOT** ""
        if(inputvalue !== "") {
            jQuery(this).css('outline', 'solid 1px red'); 
        }   

        // else if it's value **IS** ""
        else if(inputvalue === "") {
            alert('empty'); 
        }

    });

Scroll Automatically to the Bottom of the Page

one liner to smooth scroll to the bottom

window.scrollTo({ left: 0, top: document.body.scrollHeight, behavior: "smooth" });

To scroll up simply set top to 0

"document.getElementByClass is not a function"

It should be getElementsByClassName, and not getElementByClass. See this - https://developer.mozilla.org/en/DOM/document.getElementsByClassName.

Note that some browsers/versions may not support this.

Android global variable

Technically this does not answer the question, but I would recommend using the Room database instead of any global variable. https://developer.android.com/topic/libraries/architecture/room.html Even if you are 'only' needing to store a global variable and it's no big deal and what not, but using the Room database is the most elegant, native and well supported way of keeping values around the life cycle of the activity. It will help to prevent many issues, especially integrity of data. I understand that database and global variable are different but please use Room for the sake of code maintenance, app stability and data integrity.

How to represent matrices in python

((1,2,3,4),
 (5,6,7,8),
 (9,0,1,2))

Using tuples instead of lists makes it marginally harder to change the data structure in unwanted ways.

If you are going to do extensive use of those, you are best off wrapping a true number array in a class, so you can define methods and properties on them. (Or, you could NumPy, SciPy, ... if you are going to do your processing with those libraries.)

'int' object has no attribute '__getitem__'

The error:

'int' object has no attribute '__getitem__'

means that you're attempting to apply the index operator [] on an int, not a list. So is col not a list, even when it should be? Let's start from that.

Look here:

col = [[0 for col in range(5)] for row in range(6)]

Use a different variable name inside, looks like the list comprehension overwrites the col variable during iteration. (Not during the iteration when you set col, but during the following ones.)

In R, how to find the standard error of the mean?

more generally, for standard errors on any other parameter, you can use the boot package for bootstrap simulations (or write them on your own)

How to open a file for both reading and writing?

Summarize the I/O behaviors

|          Mode          |  r   |  r+  |  w   |  w+  |  a   |  a+  |
| :--------------------: | :--: | :--: | :--: | :--: | :--: | :--: |
|          Read          |  +   |  +   |      |  +   |      |  +   |
|         Write          |      |  +   |  +   |  +   |  +   |  +   |
|         Create         |      |      |  +   |  +   |  +   |  +   |
|         Cover          |      |      |  +   |  +   |      |      |
| Point in the beginning |  +   |  +   |  +   |  +   |      |      |
|    Point in the end    |      |      |      |      |  +   |  +   |

and the decision branch

enter image description here

Insert at first position of a list in Python

Use insert:

In [1]: ls = [1,2,3]

In [2]: ls.insert(0, "new")

In [3]: ls
Out[3]: ['new', 1, 2, 3]

Virtualhost For Wildcard Subdomain and Static Subdomain

<VirtualHost *:80>
  DocumentRoot /var/www/app1
  ServerName app1.example.com
</VirtualHost>

<VirtualHost *:80>
  DocumentRoot /var/www/example
  ServerName example.com
</VirtualHost>

<VirtualHost *:80>
  DocumentRoot /var/www/wildcard
  ServerName other.example.com
  ServerAlias *.example.com
</VirtualHost>

Should work. The first entry will become the default if you don't get an explicit match. So if you had app.otherexample.com point to it, it would be caught be app1.example.com.

Install Chrome extension form outside the Chrome Web Store

For Windows, you can also whitelist your extension through Windows policies. The full steps are details in this answer, but there are quicker steps:

  1. Create the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallWhitelist.
  2. For each extension you want to whitelist, add a string value whose name should be a sequence number (starting at 1) and value is the extension ID.

For instance, in order to whitelist 2 extensions with ID aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa and bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb, create a string value with name 1 and value aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, and a second value with name 2 and value bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb. This can be sum up by this registry file:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome]

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallWhitelist]
"1"="aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"2"="bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"

EDIT: actually, Chromium docs also indicate how to do it for other OS.

Bootstrap 4, How do I center-align a button?

In Bootstrap 4 one should use the text-center class to align inline-blocks.

NOTE: text-align:center; defined in a custom class you apply to your parent element will work regardless of the Bootstrap version you are using. And that's exactly what .text-center applies.

_x000D_
_x000D_
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css">_x000D_
_x000D_
<div class="container">_x000D_
  <div class="row">_x000D_
    <div class="col text-center">_x000D_
      <button class="btn btn-default">Centered button</button>_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_


If the content to be centered is block or flex (not inline-), one could use flexbox to center it:

_x000D_
_x000D_
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css">_x000D_
_x000D_
<div class="d-flex justify-content-center">_x000D_
  <button class="btn btn-default">Centered button</button>_x000D_
</div>
_x000D_
_x000D_
_x000D_

... which applies display: flex; justify-content: center to parent.

Note: don't use .row.justify-content-center instead of .d-flex.justify-content-center, as .row applies negative margins on certain responsiveness intervals, which results into unexpected horizontal scrollbars (unless .row is a direct child of .container, which applies lateral padding to counteract the negative margin, on the correct responsiveness intervals). If you must use .row, for whatever reason, override its margin and padding with .m-0.p-0, in which case you end up with pretty much the same styles as .d-flex.

Important note: The second solution is problematic when the centered content (the button) exceeds the width of the parent (.d-flex) especially when the parent has viewport width, specifically because it makes it impossible to horizontally scroll to the start of the content (left-most).
So don't use it when the content to be centered could become wider than the available parent width and all content should be accessible.

Filter dataframe rows if value in column is in a set list of values

You can also directly query your DataFrame for this information.

rpt.query('STK_ID in (600809,600141,600329)')

Or similarly search for ranges:

rpt.query('60000 < STK_ID < 70000')

Javascript loading CSV file into an array

If your not overly worried about the size of the file then it may be easier for you to store the data as a JS object in another file and import it in your . Either synchronously or asynchronously using the syntax <script src="countries.js" async></script>. Saves on you needing to import the file and parse it.

However, i can see why you wouldnt want to rewrite 10000 entries so here's a basic object orientated csv parser i wrote.

function requestCSV(f,c){return new CSVAJAX(f,c);};
function CSVAJAX(filepath,callback)
{
    this.request = new XMLHttpRequest();
    this.request.timeout = 10000;
    this.request.open("GET", filepath, true);
    this.request.parent = this;
    this.callback = callback;
    this.request.onload = function() 
    {
        var d = this.response.split('\n'); /*1st separator*/
        var i = d.length;
        while(i--)
        {
            if(d[i] !== "")
                d[i] = d[i].split(','); /*2nd separator*/
            else
                d.splice(i,1);
        }
        this.parent.response = d;
        if(typeof this.parent.callback !== "undefined")
            this.parent.callback(d);
    };
    this.request.send();
};

Which can be used like this;

var foo = requestCSV("csvfile.csv",drawlines(lines)); 

The first parameter is the file, relative to the position of your html file in this case. The second parameter is an optional callback function the runs when the file has been completely loaded.

If your file has non-separating commmas then it wont get on with this, as it just creates 2d arrays by chopping at returns and commas. You might want to look into regexp if you need that functionality.

//THIS works 

"1234","ABCD" \n
"!@£$" \n

//Gives you 
[
 [
  1234,
  'ABCD'
 ],
 [
  '!@£$'
 ]
]

//This DOESN'T!

"12,34","AB,CD" \n
"!@,£$" \n

//Gives you

[
 [
  '"12',
  '34"',
  '"AB',
  'CD'
 ]
 [
  '"!@',
  '£$'
 ]
]

If your not used to the OO methods; they create a new object (like a number, string, array) with their own local functions and variables via a 'constructor' function. Very handy in certain situations. This function could be used to load 10 different files with different callbacks all at the same time(depending on your level of csv love! )

Using getline() in C++

i think you are not pausing the program before it ended so the output you are putting after getting the inpus is not seeing on the screen right?

do:

getchar();

before the end of the program

How to create an object property from a variable value in JavaScript?

Dot notation and the properties are equivalent. So you would accomplish like so:

var myObj = new Object;
var a = 'string1';
myObj[a] = 'whatever';
alert(myObj.string1)

(alerts "whatever")

illegal use of break statement; javascript

I have a function next() which will maybe inspire you.

function queue(target) {
        var array = Array.prototype;

        var queueing = [];

        target.queue = queue;
        target.queued = queued;

        return target;

        function queued(action) {
            return function () {
                var self = this;
                var args = arguments;

                queue(function (next) {
                    action.apply(self, array.concat.apply(next, args));
                });
            };
        }

        function queue(action) {
            if (!action) {
                return;
            }

            queueing.push(action);

            if (queueing.length === 1) {
                next();
            }
        }

        function next() {
            queueing[0](function (err) {
                if (err) {
                    throw err;
                }

                queueing = queueing.slice(1);

                if (queueing.length) {
                    next();
                }
            });
        }
    }

How to open an elevated cmd using command line for Windows?

I ran into the same problem and the only way I was able to open the CMD as administrator from CMD was doing the following:

  1. Open CMD
  2. Write powershell -Command "Start-Process cmd -Verb RunAs" and press Enter
  3. A pop-up window will appear asking to open a CMD as administrator

Size-limited queue that holds last N elements in Java

The only thing I know that has limited space is the BlockingQueue interface (which is e.g. implemented by the ArrayBlockingQueue class) - but they do not remove the first element if filled, but instead block the put operation until space is free (removed by other thread).

To my knowledge your trivial implementation is the easiest way to get such an behaviour.

Mysql - delete from multiple tables with one query

usually, i would expect this as a 'cascading delete' enforced in a trigger, you would only need to delete the main record, then all the depepndent records would be deleted by the trigger logic.

this logic would be similar to what you have written.

Modify a Column's Type in sqlite3

It is possible by recreating table.Its work for me please follow following step:

  1. create temporary table using as select * from your table
  2. drop your table, create your table using modify column type
  3. now insert records from temp table to your newly created table
  4. drop temporary table

do all above steps in worker thread to reduce load on uithread

jquery .on() method with load event

As the other have mentioned, the load event does not bubble. Instead you can manually trigger a load-like event with a custom event:

$('#item').on('namespace/onload', handleOnload).trigger('namespace/onload')

If your element is already listening to a change event:

$('#item').on('change', handleChange).trigger('change')

I find this works well. Though, I stick to custom events to be more explicit and avoid side effects.

How to call a JavaScript function, declared in <head>, in the body when I want to call it

I'm not sure what you mean by "myself".

Any JavaScript function can be called by an event, but you must have some sort of event to trigger it.

e.g. On page load:

<body onload="myfunction();">

Or on mouseover:

<table onmouseover="myfunction();">

As a result the first question is, "What do you want to do to cause the function to execute?"

After you determine that it will be much easier to give you a direct answer.

How to Call VBA Function from Excel Cells?

The issue you have encountered is that UDFs cannot modify the Excel environment, they can only return a value to the calling cell.

There are several alternatives

  1. For the sample given you don't actually need VBA. This formula will work
    ='C:\Users\UserName\Desktop\[TestSample.xlsx]Sheet1'!$B$2

  2. Use a rather messy work around: See this answer

  3. You can use ExecuteExcel4Macro or OLEDB

converting string to long in python

longcan only take string convertibles which can end in a base 10 numeral. So, the decimal is causing the harm. What you can do is, float the value before calling the long. If your program is on Python 2.x where int and long difference matters, and you are sure you are not using large integers, you could have just been fine with using int to provide the key as well.

So, the answer is long(float('234.89')) or it could just be int(float('234.89')) if you are not using large integers. Also note that this difference does not arise in Python 3, because int is upgraded to long by default. All integers are long in python3 and call to covert is just int

Get Windows version in a batch file

Have you tried using the wmic commands?

Try wmic os get version

This will give you the version number in a command line, then you just need to integrate into the batch file.

Sort dataGridView columns in C# ? (Windows Form)

You can control the data returned from SQL database by ordering the data returned:

orderby [Name]

If you execute the SQL query from your application, order the data returned. For example, make a function that calls the procedure or executes the SQL and give it a parameter that gets the orderby criteria. Because if you ordered the data returned from database it will consume time but order it since it's executed as you say that you want it to be ordered not from the UI you want it to be ordered in the run time so order it when executing the SQL query.

Connecting to remote MySQL server using PHP

  • firewall of the server must be set-up to enable incomming connections on port 3306
  • you must have a user in MySQL who is allowed to connect from % (any host) (see manual for details)

The current problem is the first one, but right after you resolve it you will likely get the second one.

Run on server option not appearing in Eclipse

Right click on the project, go to "Run as", select "Run configurations" and create a run configuration.

AngularJS passing data to $http.get request

Starting from AngularJS v1.4.8, you can use get(url, config) as follows:

var data = {
 user_id:user.id
};

var config = {
 params: data,
 headers : {'Accept' : 'application/json'}
};

$http.get(user.details_path, config).then(function(response) {
   // process response here..
 }, function(response) {
});

T-SQL Subquery Max(Date) and Joins

SELECT
    *
FROM
    (SELECT MAX(PriceDate) AS MaxP, Partid FROM MyPrices GROUP BY Partid) MaxP 
    JOIN
    MyPrices MP On MaxP.Partid = MP.Partid AND MaxP.MaxP = MP.PriceDate
    JOIN
    MyParts P ON MP.Partid = P.Partid

You to get the latest pricedate for partid first (a standard aggregate), then join it back to get the prices (which can't be in the aggregate), followed by getting the part details.

How to change bower's default components folder?

Hi i am same problem and resolve this ways.

windows user and vs cant'create .bowerrc file.

in cmd go any folder

install any packages which is contains .bowerrc file forexample

bower install angular-local-storage

this plugin contains .bowerrc file. copy that and go to your project and paste this file.

and in visual studio - solution explorer - show all files and include project seen .bowerrc file

i resolve this ways :)

WPF loading spinner

CircularProgressBarBlue.xaml

<UserControl 
x:Class="CircularProgressBarBlue"   
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Background="Transparent"
Name="progressBar">
<UserControl.Resources>
    <Storyboard x:Key="spinning" >
        <DoubleAnimation 
            Storyboard.TargetName="SpinnerRotate" 
            Storyboard.TargetProperty="(RotateTransform.Angle)"                 
            From="0" 
            To="360"                 
            RepeatBehavior="Forever"/>
    </Storyboard>
</UserControl.Resources>
<Grid 
    x:Name="LayoutRoot" 
    Background="Transparent" 
    HorizontalAlignment="Center" 
    VerticalAlignment="Center">
    <Image Source="C:\SpinnerImage\BlueSpinner.png" RenderTransformOrigin="0.5,0.5" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
        <Image.RenderTransform>
            <RotateTransform 
                x:Name="SpinnerRotate"
                Angle="0"/>
        </Image.RenderTransform>
    </Image>


</Grid>

CircularProgressBarBlue.xaml.cs

using System;

using System.Windows;

using System.Windows.Media.Animation;


        /// <summary>
    /// Interaction logic for CircularProgressBarBlue.xaml
    /// </summary>
    public partial class CircularProgressBarBlue
    {
        private Storyboard _sb;

        public CircularProgressBarBlue()
        {
            InitializeComponent();
            StartStoryBoard();
            IsVisibleChanged += CircularProgressBarBlueIsVisibleChanged;
        }

        void CircularProgressBarBlueIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            if (_sb == null) return;
            if (e != null && e.NewValue != null && (((bool)e.NewValue)))
            {
                _sb.Begin();
                _sb.Resume();
            }
            else
            {
                _sb.Stop();
            }
        }

        void StartStoryBoard()
        {
            try
            {
                _sb = (Storyboard)TryFindResource("spinning");
                if (_sb != null)
                    _sb.Begin();
            }
            catch
            { }
        }
    }

How to reload/refresh jQuery dataTable?

Destroy the datatable first and then draw the datatable.

$('#table1').DataTable().destroy();
$('#table1').find('tbody').append("<tr><td><value1></td><td><value1></td></tr>");
$('#table1').DataTable().draw();

How to use a variable of one method in another method?

You can't. Variables defined inside a method are local to that method.

If you want to share variables between methods, then you'll need to specify them as member variables of the class. Alternatively, you can pass them from one method to another as arguments (this isn't always applicable).


Looks like you're using instance methods instead of static ones.

If you don't want to create an object, you should declare all your methods static, so something like

private static void methodName(Argument args...)

If you want a variable to be accessible by all these methods, you should initialise it outside the methods and to limit its scope, declare it private.

private static int[][] array = new int[3][5];

Global variables are usually looked down upon (especially for situations like your one) because in a large-scale program they can wreak havoc, so making it private will prevent some problems at the least.

Also, I'll say the usual: You should try to keep your code a bit tidy. Use descriptive class, method and variable names and keep your code neat (with proper indentation, linebreaks etc.) and consistent.

Here's a final (shortened) example of what your code should be like:

public class Test3 {
    //Use this array in your methods
    private static int[][] scores = new int[3][5];

    /* Rather than just "Scores" name it so people know what
     * to expect
     */
    private static void createScores() {
        //Code...
    }
    //Other methods...

    /* Since you're now using static methods, you don't 
     * have to initialise an object and call its methods.
     */
    public static void main(String[] args){
        createScores();
        MD();   //Don't know what these do
        sumD(); //so I'll leave them.
    }
}

Ideally, since you're using an array, you would create the array in the main method and pass it as an argument across each method, but explaining how that works is probably a whole new question on its own so I'll leave it at that.

enum to string in modern C++11 / C++14 / C++17 and future C++20

If your enum looks like

enum MyEnum
{
  AAA = -8,
  BBB = '8',
  CCC = AAA + BBB
};

You can move the content of the enum to a new file:

AAA = -8,
BBB = '8',
CCC = AAA + BBB

And then the values can be surrounded by a macro:

// default definition
#ifned ITEM(X,Y)
#define ITEM(X,Y)
#endif

// Items list
ITEM(AAA,-8)
ITEM(BBB,'8')
ITEM(CCC,AAA+BBB)

// clean up
#undef ITEM

Next step may be include the items in the enum again:

enum MyEnum
{
  #define ITEM(X,Y) X=Y,
  #include "enum_definition_file"
};

And finally you can generate utility functions about this enum:

std::string ToString(MyEnum value)
{
  switch( value )
  {
    #define ITEM(X,Y) case X: return #X;
    #include "enum_definition_file"
  }

  return "";
}

MyEnum FromString(std::string const& value)
{
  static std::map<std::string,MyEnum> converter
  {
    #define ITEM(X,Y) { #X, X },
    #include "enum_definition_file"
  };

  auto it = converter.find(value);
  if( it != converter.end() )
    return it->second;
  else
    throw std::runtime_error("Value is missing");
}

The solution can be applied to older C++ standards and it does not use modern C++ elements but it can be used to generate lot of code without too much effort and maintenance.

Can I safely delete contents of Xcode Derived data folder?

I would say it's safe--I often delete the contents of the folder for many kind of iOS projects, this way. And, I haven't had any issues with builds or submitting to the App Store. The procedure deletes derived data and cleans a project's cached assets, for both Xcode 5 and 6.

Sometimes, simply calling rm -rf on the Derived Data directory leaves a lingering file or two, but my script loops until all files are deleted.

Change Default branch in gitlab

First I needed to remote into my server with ssh. If someone has a non ssh way of doing this please post.

I found my bare repositories at

cd /var/opt/gitlab/git-data/repositories/group-name/project-name.git

used

git branch 

to see the wrong active branch

git symbolic-ref HEAD refs/heads/master

to change the master to to be the branch called master then use the web interface and "git branch" to confirm.

Write code to convert given number into words (eg 1234 as input should output one thousand two hundred and thirty four)

Instead of switch statements, consider using tables of strings indexed by a small value.

const char * const ones[20] = {"zero", "one", "two", ..., "nineteen"};
const char * const tens[10] = {"", "ten", "twenty", ..., "ninety"};

Now break the problem into small pieces. Write a function that can output a single-digit number. Then write a function that can handle a two-digit number (which will probably use the previous function). Continue building up the functions as necessary.

Create a list of test cases with expected output, and write code to call your functions and check the output, so that, as you fix problems for the more complicated cases, you can be sure that the simpler cases continue to work.

In Python, how do I determine if an object is iterable?

Since Python 3.5 you can use the typing module from the standard library for type related things:

from typing import Iterable

...

if isinstance(my_item, Iterable):
    print(True)