Programs & Examples On #Whack

How to set an image's width and height without stretching it?

CSS3 object-fit

Am not sure how far its been implemented by webkit, IE and firefox. But Opera works like magic

object-fit works with SVG content, but the same effect can also be achieved by setting the preserveAspectRatio="" attribute in the SVG itself.

img {
  height: 100px;
  width: 100px;
  -o-object-fit: contain;
}

Chris Mills demo's it here http://dev.opera.com/articles/view/css3-object-fit-object-position/

Why do I get "Exception; must be caught or declared to be thrown" when I try to compile my Java code?

The first error

java.lang.Exception; must be caught or declared to be thrown byte[] encrypted = encrypt(concatURL);

means that your encrypt method throws an exception that is not being handled or declared by the actionPerformed method where you are calling it. Read all about it at the Java Exceptions Tutorial.

You have a couple of choices that you can pick from to get the code to compile.

  • You can remove throws Exception from your encrypt method and actually handle the exception inside encrypt.
  • You can remove the try/catch block from encrypt and add throws Exception and the exception handling block to your actionPerformed method.

It's generally better to handle an exception at the lowest level that you can, instead of passing it up to a higher level.

The second error just means that you need to add a return statement to whichever method contains line 109 (also encrypt, in this case). There is a return statement in the method, but if an exception is thrown it might not be reached, so you either need to return in the catch block, or remove the try/catch from encrypt, as I mentioned before.

Syntax for a for loop in ruby

Ruby's enumeration loop syntax is different:

collection.each do |item|
...
end

This reads as "a call to the 'each' method of the array object instance 'collection' that takes block with 'blockargument' as argument". The block syntax in Ruby is 'do ... end' or '{ ... }' for single line statements.

The block argument '|item|' is optional but if provided, the first argument automatically represents the looped enumerated item.

How to fix homebrew permissions?

To resolve errors for Brew permissions on folder run

brew prune

This will resolve the issues & we don't have to chown any directories.

What is the difference between an IntentService and a Service?

See Tejas Lagvankar's post about this subject. Below are some key differences between Service and IntentService and other components.

enter image description here

How do I open phone settings when a button is clicked?

in ios10/ Xcode 8 in simulator:

UIApplication.shared.openURL(URL(string:UIApplicationOpenSettingsURLString)!)

works

UIApplication.shared.openURL(URL(string:"prefs:root=General")!)

does not.

System.out.println() shortcut on Intellij IDEA

Yeah, you can do it. Just open Settings -> Live Templates. Create new one with syso as abbreviation and System.out.println($END$); as Template text.

vue.js 'document.getElementById' shorthand

Try not to do DOM manipulation by referring the DOM directly, it will have lot of performance issue, also event handling becomes more tricky when we try to access DOM directly, instead use data and directives to manipulate the DOM.

This will give you more control over the manipulation, also you will be able to manage functionalities in the modular format.

Parse HTML in Android

I just encountered this problem. I tried a few things, but settled on using JSoup. The jar is about 132k, which is a bit big, but if you download the source and take out some of the methods you will not be using, then it is not as big.
=> Good thing about it is that it will handle badly formed HTML

Here's a good example from their site.

File input = new File("/tmp/input.html");
Document doc = Jsoup.parse(input, "UTF-8", "http://example.com/");

//http://jsoup.org/cookbook/input/load-document-from-url
//Document doc = Jsoup.connect("http://example.com/").get();

Element content = doc.getElementById("content");
Elements links = content.getElementsByTag("a");
for (Element link : links) {
  String linkHref = link.attr("href");
  String linkText = link.text();
}

Foreign key constraints: When to use ON UPDATE and ON DELETE

You'll need to consider this in context of the application. In general, you should design an application, not a database (the database simply being part of the application).

Consider how your application should respond to various cases.

The default action is to restrict (i.e. not permit) the operation, which is normally what you want as it prevents stupid programming errors. However, on DELETE CASCADE can also be useful. It really depends on your application and how you intend to delete particular objects.

Personally, I'd use InnoDB because it doesn't trash your data (c.f. MyISAM, which does), rather than because it has FK constraints.

How to compare strings in C conditional preprocessor-directives

As already stated above, the ISO-C11 preprocessor does not support string comparison. However, the problem of assigning a macro with the “opposite value” can be solved with “token pasting” and “table access”. Jesse’s simple concatenate/stringify macro-solution fails with gcc 5.4.0 because the stringization is done before the evaluation of the concatenation (conforming to ISO C11). However, it can be fixed:

#define P_(user) user ## _VS
#define VS(user) P_ (user)
#define S(U) S_(U)
#define S_(U) #U

#define jack_VS  queen
#define queen_VS jack

S (VS (jack))
S (jack)
S (VS (queen))
S (queen)

#define USER jack          // jack    or queen, your choice
#define USER_VS USER##_VS  // jack_VS or queen_VS
S (USER)
S (USER_VS)

The first line (macro P_()) adds one indirection to let the next line (macro VS()) finish the concatenation before the stringization (see Why do I need double layer of indirection for macros?). The stringization macros (S() and S_()) are from Jesse.

The table (macros jack_VS and queen_VS) which is much easier to maintain than the if-then-else construction of the OP is from Jesse.

Finally, the next four-line block invokes the function-style macros. The last four-line block is from Jesse’s answer.

Storing the code in foo.c and invoking the preprocessor gcc -nostdinc -E foo.c yields:

# 1 "foo.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "foo.c"
# 9 "foo.c"
"queen"
"jack"
"jack"
"queen"



"jack"
"USER_VS"

The output is as expected. The last line shows that the USER_VS macro is not expanded before stringization.

Log all queries in mysql

Start mysql with the --log option:

mysqld --log=log_file_name

or place the following in your my.cnf file:

log = log_file_name

Either one will log all queries to log_file_name.

You can also log only slow queries using the --log-slow-queries option instead of --log. By default, queries that take 10 seconds or longer are considered slow, you can change this by setting long_query_time to the number of seconds a query must take to execute before being logged.

Should __init__() call the parent class's __init__()?

If you need something from super's __init__ to be done in addition to what is being done in the current class's __init__, you must call it yourself, since that will not happen automatically. But if you don't need anything from super's __init__, no need to call it. Example:

>>> class C(object):
        def __init__(self):
            self.b = 1


>>> class D(C):
        def __init__(self):
            super().__init__() # in Python 2 use super(D, self).__init__()
            self.a = 1


>>> class E(C):
        def __init__(self):
            self.a = 1


>>> d = D()
>>> d.a
1
>>> d.b  # This works because of the call to super's init
1
>>> e = E()
>>> e.a
1
>>> e.b  # This is going to fail since nothing in E initializes b...
Traceback (most recent call last):
  File "<pyshell#70>", line 1, in <module>
    e.b  # This is going to fail since nothing in E initializes b...
AttributeError: 'E' object has no attribute 'b'

__del__ is the same way, (but be wary of relying on __del__ for finalization - consider doing it via the with statement instead).

I rarely use __new__. I do all the initialization in __init__.

What is a typedef enum in Objective-C?

enum is used to assign value to enum elements which cannot be done in struct. So everytime instead of accessing the complete variable we can do it by the value we assign to the variables in enum. By default it starts with 0 assignment but we can assign it any value and the next variable in enum will be assigned a value the previous value +1.

Center text in table cell

How about simply (Please note, come up with a better name for the class name this is simply an example):

.centerText{
   text-align: center;
}


<div>
   <table style="width:100%">
   <tbody>
   <tr>
      <td class="centerText">Cell 1</td>
      <td>Cell 2</td>
    </tr>
    <tr>
      <td class="centerText">Cell 3</td>
      <td>Cell 4</td>
    </tr>
    </tbody>
    </table>
</div>

Example here

You can place the css in a separate file, which is recommended. In my example, I created a file called styles.css and placed my css rules in it. Then include it in the html document in the <head> section as follows:

<head>
    <link href="styles.css" rel="stylesheet" type="text/css">
</head>

The alternative, not creating a seperate css file, not recommended at all... Create <style> block in your <head> in the html document. Then just place your rules there.

<head>
 <style type="text/css">
   .centerText{
       text-align: center;
    }
 </style>
</head>

Sorting Values of Set

You're using the default comparator to sort a Set<String>. In this case, that means lexicographic order. Lexicographically, "12" comes before "15", comes before "5".

Either use a Set<Integer>:

Set<Integer> set=new HashSet<Integer>();
set.add(12);
set.add(15);
set.add(5);

Or use a different comparator:

Collections.sort(list, new Comparator<String>() {
    public int compare(String a, String b) {
        return Integer.parseInt(a) - Integer.parseInt(b);
    }
});

What does "publicPath" in Webpack do?

The webpack2 documentation explains this in a much cleaner way: https://webpack.js.org/guides/public-path/#use-cases

webpack has a highly useful configuration that let you specify the base path for all the assets on your application. It's called publicPath.

How to get difference between two dates in Year/Month/Week/Day?

Partly as a preparation for trying to answer this question correctly (and maybe even definitively...), partly to examine how much one can trust code that is pasted on SO, and partly as an exercise in finding bugs, I created a bunch of unit tests for this question, and applied them to many proposed solutions from this page and a couple of duplicates.

The results are conclusive: not a single one of the code contributions accurately answers the question. Update: I now have four correct solutions to this question, including my own, see updates below.

Code tested

From this question, I tested code by the following users: Mohammed Ijas Nasirudeen, ruffin, Malu MN, Dave, pk., Jani, lc.

These were all the answers which provided all three of years, months, and days in their code. Note that two of these, Dave and Jani, gave the total number of days and months, rather than the total number of months left after counting the years, and the total number of days left after counting the months. I think the answers are wrong in terms of what the OP seemed to want, but the unit tests obviously don't tell you much in these cases. (Note that in Jani's case this was my error and his code was actually correct - see Update 4 below)

The answers by Jon Skeet, Aghasoleimani, Mukesh Kumar, Richard, Colin, sheir, just i saw, Chalkey and Andy, were incomplete. This doesn't mean that the answers weren't any good, in fact several of them are useful contributions towards a solution. It just means that there wasn't code taking two DateTimes and returning 3 ints that I could properly test. Four of these do however talk about using TimeSpan. As many people have mentioned, TimeSpan doesn't return counts of anything larger than days.

The other answers I tested were from

  • question 3054715 - LukeH, ho1 and this. ___curious_geek
  • question 6260372 - Chuck Rostance and Jani (same answer as this question)
  • question 9 (!) - Dylan Hayes, Jon and Rajeshwaran S P

this.___curious_geek's answer is code on a page he linked to, which I don't think he wrote. Jani's answer is the only one which uses an external library, Time Period Library for .Net.

All other answers on all these questions seemed to be incomplete. Question 9 is about age in years, and the three answers are ones which exceeded the brief and calculated years, months and days. If anyone finds further duplicates of this question please let me know.

How I tested

Quite simply: I made an interface

public interface IDateDifference
{
  void SetDates(DateTime start, DateTime end);
  int GetYears();
  int GetMonths();
  int GetDays();

}

For each answer I wrote a class implementing this interface, using the copied and pasted code as a basis. Of course I had to adapt functions with different signatures etc, but I tried to make the minimal edits to do so, preserving all the logic code.

I wrote a bunch of NUnit tests in an abstract generic class

[TestFixture]
public abstract class DateDifferenceTests<DDC> where DDC : IDateDifference, new()

and added an empty derived class

public class Rajeshwaran_S_P_Test : DateDifferenceTests<Rajeshwaran_S_P>
{
}

to the source file for each IDateDifference class.

NUnit is clever enough to do the rest.

The tests

A couple of these were written in advance and the rest were written to try and break seemingly working implementations.

[TestFixture]
public abstract class DateDifferenceTests<DDC> where DDC : IDateDifference, new()
{
  protected IDateDifference ddClass;

  [SetUp]
  public void Init()
  {
    ddClass = new DDC();
  }

  [Test]
  public void BasicTest()
  {
    ddClass.SetDates(new DateTime(2012, 12, 1), new DateTime(2012, 12, 25));
    CheckResults(0, 0, 24);
  }

  [Test]
  public void AlmostTwoYearsTest()
  {
    ddClass.SetDates(new DateTime(2010, 8, 29), new DateTime(2012, 8, 14));
    CheckResults(1, 11, 16);
  }

  [Test]
  public void AlmostThreeYearsTest()
  {
    ddClass.SetDates(new DateTime(2009, 7, 29), new DateTime(2012, 7, 14));
    CheckResults(2, 11, 15);
  }

  [Test]
  public void BornOnALeapYearTest()
  {
    ddClass.SetDates(new DateTime(2008, 2, 29), new DateTime(2009, 2, 28));
    CheckControversialResults(0, 11, 30, 1, 0, 0);
  }

  [Test]
  public void BornOnALeapYearTest2()
  {
    ddClass.SetDates(new DateTime(2008, 2, 29), new DateTime(2009, 3, 1));
    CheckControversialResults(1, 0, 0, 1, 0, 1);
  }


  [Test]
  public void LongMonthToLongMonth()
  {
    ddClass.SetDates(new DateTime(2010, 1, 31), new DateTime(2010, 3, 31));
    CheckResults(0, 2, 0);
  }

  [Test]
  public void LongMonthToLongMonthPenultimateDay()
  {
    ddClass.SetDates(new DateTime(2009, 1, 31), new DateTime(2009, 3, 30));
    CheckResults(0, 1, 30);
  }

  [Test]
  public void LongMonthToShortMonth()
  {
    ddClass.SetDates(new DateTime(2009, 8, 31), new DateTime(2009, 9, 30));
    CheckControversialResults(0, 1, 0, 0, 0, 30);
  }

  [Test]
  public void LongMonthToPartWayThruShortMonth()
  {
    ddClass.SetDates(new DateTime(2009, 8, 31), new DateTime(2009, 9, 10));
    CheckResults(0, 0, 10);
  }

  private void CheckResults(int years, int months, int days)
  {
    Assert.AreEqual(years, ddClass.GetYears());
    Assert.AreEqual(months, ddClass.GetMonths());
    Assert.AreEqual(days, ddClass.GetDays());
  }

  private void CheckControversialResults(int years, int months, int days,
    int yearsAlt, int monthsAlt, int daysAlt)
  {
    // gives the right output but unhelpful messages
    bool success = ((ddClass.GetYears() == years
                     && ddClass.GetMonths() == months
                     && ddClass.GetDays() == days)
                    ||
                    (ddClass.GetYears() == yearsAlt
                     && ddClass.GetMonths() == monthsAlt
                     && ddClass.GetDays() == daysAlt));

    Assert.IsTrue(success);
  }
}

Most of the names are slightly silly and don't really explain why code might fail the test, however looking at the two dates and the answer(s) should be enough to understand the test.

There are two functions that do all the Asserts, CheckResults() and CheckControversialResults(). These work well to save typing and give the right results, but unfortunately they make it harder to see exactly what went wrong (because the Assert in CheckControversialResults() will fail with "Expected true", rather than telling you which value was incorrect. If anyone has a better way to do this (avoid writing the same checks each time, but have more useful error messages) please let me know.

CheckControversialResults() is used for a couple of cases where there seem to be two different opinions on what is right. I have an opinion of my own, but I thought I should be liberal in what I accepted here. The gist of this is deciding whether one year after Feb 29 is Feb 28 or Mar 1.

These tests are the crux of the matter, and there could very well be errors in them, so please do comment if you find one which is wrong. It would be also good to hear some suggestions for other tests to check any future iterations of answers.

No test involves time of day - all DateTimes are at midnight. Including times, as long as it's clear how rounding up and down to days works (I think it is), might show up even more flaws.

The results

The complete scoreboard of results is as follows:

ChuckRostance_Test 3 failures               S S S F S S F S F
Dave_Test 6 failures                        F F S F F F F S S
Dylan_Hayes_Test 9 failures                 F F F F F F F F F
ho1_Test 3 failures                         F F S S S S F S S
Jani_Test 6 failures                        F F S F F F F S S
Jon_Test 1 failure                          S S S S S S F S S
lc_Test 2 failures                          S S S S S F F S S
LukeH_Test 1 failure                        S S S S S S F S S
Malu_MN_Test 1 failure                      S S S S S S S F S
Mohammed_Ijas_Nasirudeen_Test 2 failures    F S S F S S S S S
pk_Test 6 failures                          F F F S S F F F S
Rajeshwaran_S_P_Test 7 failures             F F S F F S F F F
ruffin_Test 3 failures                      F S S F S S F S S
this_curious_geek_Test 2 failures           F S S F S S S S S

But note that Jani's solution was actually correct and passed all tests - see update 4 below.

The columns are in alphabetical order of test name:

  • AlmostThreeYearsTest
  • AlmostTwoYearsTest
  • BasicTest
  • BornOnALeapYearTest
  • BornOnALeapYearTest2
  • LongMonthToLongMonth
  • LongMonthToLongMonthPenultimateDay
  • LongMonthToPartWayThruShortMonth
  • LongMonthToShortMonth

Three answers failed only 1 test each, Jon's, LukeH's and Manu MN's. Bear in mind these tests were probably written specifically to address flaws in those answers.

Every test was passed by at least one piece of code, which is slightly reassuring that none of the tests are erroneous.

Some answers failed a lot of tests. I hope no-one feels this is a condemnation of that poster's efforts. Firstly the number of successes is fairly arbitrary as the tests don't evenly cover the problem areas of the question space. Secondly this is not production code - answers are posted so people can learn from them, not copy them exactly into their programs. Code which fails a lot of tests can still have great ideas in it. At least one piece which failed a lot of tests had a small bug in it which I didn't fix. I'm grateful to anyone who took the time to share their work with everyone else, for making this project so interesting.

My conclusions

There are three:

  1. Calendars are hard. I wrote nine tests, including three where two answers are possible. Some of the tests where I only had one answer might not be unanimously agreed with. Just thinking about exactly what we mean when we say '1 month later' or '2 years earlier' is tricky in a lot of situations. And none of this code had to deal with all the complexities of things like working out when leap years are. All of it uses library code to handle dates. If you imagine the 'spec' for telling time in days, weeks, months and years written out, there's all sorts of cruft. Because we know it pretty well since primary school, and use it everyday, we are blind to many of the idiosyncracies. The question is not an academic one - various types of decomposition of time periods into years, quarters and months are essential in accounting software for bonds and other financial products.

  2. Writing correct code is hard. There were a lot of bugs. In slightly more obscure topics or less popular questions than the chances of a bug existing without having been pointed out by a commenter are much, much higher than for this question. You should really never, never copy code from SO into your program without understanding exactly what it does. The flipside of this is that you probably shouldn't write code in your answer that is ready to be copied and pasted, but rather intelligent and expressive pseudo-code that allows someone to understand the solution and implement their own version (with their own bugs!)

  3. Unit tests are helpful. I am still meaning to post my own solution to this when I get round to it (for someone else to find the hidden, incorrect assumptions in!) Doing this was a great example of 'saving the bugs' by turning them into unit tests to fix the next version of the code with.

Update

The whole project is now at https://github.com/jwg4/date-difference This includes my own attempt jwg.cs, which passes all the tests I currently have, including a few new ones which check for proper time of day handling. Feel free to add either more tests to break this and other implementations or better code for answering the question.

Update 2

@MattJohnson has added an implementation which uses Jon Skeet's NodaTime. It passes all the current tests.

Update 3

@KirkWoll's answer to Difference in months between two dates has been added to the project on github. It passes all the current tests.

Update 4

@Jani pointed out in a comment that I had used his code wrongly. He did suggest methods that counted the years, months and days correctly, (alongside some which count the total number of days and months, not the remainders) however I mistakenly used the wrong ones in my test code. I have corrected my wrapper around his code and it now passes all tests. There are now four correct solutions, of which Jani's was the first. Two use libraries (Intenso.TimePeriod and NodaTime) and two are written from scratch.

How to convert string to date to string in Swift iOS?

See answer from Gary Makin. And you need change the format or data. Because the data that you have do not fit under the chosen format. For example this code works correct:

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "MM-dd-yyyy"
let dateObj = dateFormatter.dateFromString("10 10 2001")
print("Dateobj: \(dateObj)")

Angular 2 : No NgModule metadata found

you need to enable the ngModel directive. This is done by adding the FormsModule to the imports[] array in the AppModule.

You then also need to add the import from @angular/forms in the app.module.ts file: import { FormsModule } from '@angular/forms';

Delete first character of a string in Javascript

try

s.replace(/^0/,'')

_x000D_
_x000D_
console.log("0string  =>", "0string".replace(/^0/,'') );_x000D_
console.log("00string =>", "00string".replace(/^0/,'') );_x000D_
console.log("string00 =>", "string00".replace(/^0/,'') );
_x000D_
_x000D_
_x000D_

How do I specify row heights in CSS Grid layout?

One of the Related posts gave me the (simple) answer.

Apparently the auto value on the grid-template-rows property does exactly what I was looking for.

.grid {
    display:grid;
    grid-template-columns: 1fr 1.5fr 1fr;
    grid-template-rows: auto auto 1fr 1fr 1fr auto auto;
    grid-gap:10px;
    height: calc(100vh - 10px);
}

Add column to SQL Server

Add new column to Table with default value.

ALTER TABLE NAME_OF_TABLE
ADD COLUMN_NAME datatype
DEFAULT DEFAULT_VALUE

What is wrong with this code that uses the mysql extension to fetch data from a database in PHP?

Try

$query = mysql_query("SELECT * FROM users WHERE name = 'Admin' ")or die(mysql_error());

and check if this throw any error.

Then use while($rows = mysql_fetch_assoc($query)):

And finally display it as

echo $name . "<br/>" . $address . "<br/>" . $email . "<br/>" . $subject . "<br/>" . $comment . "<br/><br/>" . ;

Do not user mysql_* as its deprecated.

javac is not recognized as an internal or external command, operable program or batch file

TL;DR

For experienced readers:

  1. Find the Java path; it looks like this: C:\Program Files\Java\jdkxxxx\bin\
  2. Start-menu search for "environment variable" to open the options dialog.
  3. Examine PATH. Remove old Java paths.
  4. Add the new Java path to PATH.
  5. Edit JAVA_HOME.
  6. Close and re-open console/IDE.

Welcome!

You have encountered one of the most notorious technical issues facing Java beginners: the 'xyz' is not recognized as an internal or external command... error message.

In a nutshell, you have not installed Java correctly. Finalizing the installation of Java on Windows requires some manual steps. You must always perform these steps after installing Java, including after upgrading the JDK.

Environment variables and PATH

(If you already understand this, feel free to skip the next three sections.)

When you run javac HelloWorld.java, cmd must determine where javac.exe is located. This is accomplished with PATH, an environment variable.

An environment variable is a special key-value pair (e.g. windir=C:\WINDOWS). Most came with the operating system, and some are required for proper system functioning. A list of them is passed to every program (including cmd) when it starts. On Windows, there are two types: user environment variables and system environment variables.

You can see your environment variables like this:

C:\>set
ALLUSERSPROFILE=C:\ProgramData
APPDATA=C:\Users\craig\AppData\Roaming
CommonProgramFiles=C:\Program Files\Common Files
CommonProgramFiles(x86)=C:\Program Files (x86)\Common Files
CommonProgramW6432=C:\Program Files\Common Files
...

The most important variable is PATH. It is a list of paths, separated by ;. When a command is entered into cmd, each directory in the list will be scanned for a matching executable.

On my computer, PATH is:

C:\>echo %PATH%
C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPower
Shell\v1.0\;C:\ProgramData\Microsoft\Windows\Start Menu\Programs;C:\Users\craig\AppData\
Roaming\Microsoft\Windows\Start Menu\Programs;C:\msys64\usr\bin;C:\msys64\mingw64\bin;C:\
msys64\mingw32\bin;C:\Program Files\nodejs\;C:\Program Files (x86)\Yarn\bin\;C:\Users\
craig\AppData\Local\Yarn\bin;C:\Program Files\Java\jdk-10.0.2\bin;C:\ProgramFiles\Git\cmd;
C:\Program Files\Oracle\VirtualBox;C:\Program Files\7-Zip\;C:\Program Files\PuTTY\;C:\
Program Files\launch4j;C:\Program Files (x86)\NSIS\Bin;C:\Program Files (x86)\Common Files
\Adobe\AGL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program
Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\iCLS Client\;
C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files
(x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\Intel\iCLS
Client\;C:\Users\craig\AppData\Local\Microsoft\WindowsApps

When you run javac HelloWorld.java, cmd, upon realizing that javac is not an internal command, searches the system PATH followed by the user PATH. It mechanically enters every directory in the list, and checks if javac.com, javac.exe, javac.bat, etc. is present. When it finds javac, it runs it. When it does not, it prints 'javac' is not recognized as an internal or external command, operable program or batch file.

You must add the Java executables directory to PATH.

JDK vs. JRE

(If you already understand this, feel free to skip this section.)

When downloading Java, you are offered a choice between:

  • The Java Runtime Environment (JRE), which includes the necessary tools to run Java programs, but not to compile new ones – it contains java but not javac.
  • The Java Development Kit (JDK), which contains both java and javac, along with a host of other development tools. The JDK is a superset of the JRE.

You must make sure you have installed the JDK. If you have only installed the JRE, you cannot execute javac because you do not have an installation of the Java compiler on your hard drive. Check your Windows programs list, and make sure the Java package's name includes the words "Development Kit" in it.

Don't use set

(If you weren't planning to anyway, feel free to skip this section.)

Several other answers recommend executing some variation of:

C:\>:: DON'T DO THIS
C:\>set PATH=C:\Program Files\Java\jdk1.7.0_09\bin

Do not do that. There are several major problems with that command:

  1. This command erases everything else from PATH and replaces it with the Java path. After executing this command, you might find various other commands not working.
  2. Your Java path is probably not C:\Program Files\Java\jdk1.7.0_09\bin – you almost definitely have a newer version of the JDK, which would have a different path.
  3. The new PATH only applies to the current cmd session. You will have to reenter the set command every time you open Command Prompt.

Points #1 and #2 can be solved with this slightly better version:

C:\>:: DON'T DO THIS EITHER
C:\>set PATH=C:\Program Files\Java\<enter the correct Java folder here>\bin;%PATH%

But it is just a bad idea in general.

Find the Java path

The right way begins with finding where you have installed Java. This depends on how you have installed Java.

Exe installer

You have installed Java by running a setup program. Oracle's installer places versions of Java under C:\Program Files\Java\ (or C:\Program Files (x86)\Java\). With File Explorer or Command Prompt, navigate to that directory.

Each subfolder represents a version of Java. If there is only one, you have found it. Otherwise, choose the one that looks like the newer version. Make sure the folder name begins with jdk (as opposed to jre). Enter the directory.

Then enter the bin directory of that.

You are now in the correct directory. Copy the path. If in File Explorer, click the address bar. If in Command Prompt, copy the prompt.

The resulting Java path should be in the form of (without quotes):

C:\Program Files\Java\jdkxxxx\bin\

Zip file

You have downloaded a .zip containing the JDK. Extract it to some random place where it won't get in your way; C:\Java\ is an acceptable choice.

Then locate the bin folder somewhere within it.

You are now in the correct directory. Copy its path. This is the Java path.

Remember to never move the folder, as that would invalidate the path.

Open the settings dialog

That is the dialog to edit PATH. There are numerous ways to get to that dialog, depending on your Windows version, UI settings, and how messed up your system configuration is.

Try some of these:

  • Start Menu/taskbar search box » search for "environment variable"
  • Win + R » control sysdm.cpl,,3
  • Win + R » SystemPropertiesAdvanced.exe » Environment Variables
  • File Explorer » type into address bar Control Panel\System and Security\System » Advanced System Settings (far left, in sidebar) » Environment Variables
  • Desktop » right-click This PC » Properties » Advanced System Settings » Environment Variables
  • Start Menu » right-click Computer » Properties » Advanced System Settings » Environment Variables
  • Control Panel (icon mode) » System » Advanced System Settings » Environment Variables
  • Control Panel (category mode) » System and Security » System » Advanced System Settings » Environment Variables
  • Desktop » right-click My Computer » Advanced » Environment Variables
  • Control Panel » System » Advanced » Environment Variables

Any of these should take you to the right settings dialog.

If you are on Windows 10, Microsoft has blessed you with a fancy new UI to edit PATH. Otherwise, you will see PATH in its full semicolon-encrusted glory, squeezed into a single-line textbox. Do your best to make the necessary edits without breaking your system.

Clean PATH

Look at PATH. You almost definitely have two PATH variables (because of user vs. system environment variables). You need to look at both of them.

Check for other Java paths and remove them. Their existence can cause all sorts of conflicts. (For instance, if you have JRE 8 and JDK 11 in PATH, in that order, then javac will invoke the Java 11 compiler, which will create version 55 .class files, but java will invoke the Java 8 JVM, which only supports up to version 52, and you will experience unsupported version errors and not be able to compile and run any programs.) Sidestep these problems by making sure you only have one Java path in PATH. And while you're at it, you may as well uninstall old Java versions, too. And remember that you don't need to have both a JDK and a JRE.

If you have C:\ProgramData\Oracle\Java\javapath, remove that as well. Oracle intended to solve the problem of Java paths breaking after upgrades by creating a symbolic link that would always point to the latest Java installation. Unfortunately, it often ends up pointing to the wrong location or simply not working. It is better to remove this entry and manually manage the Java path.

Now is also a good opportunity to perform general housekeeping on PATH. If you have paths relating to software no longer installed on your PC, you can remove them. You can also shuffle the order of paths around (if you care about things like that).

Add to PATH

Now take the Java path you found three steps ago, and place it in the system PATH.

It shouldn't matter where in the list your new path goes; placing it at the end is a fine choice.

If you are using the pre-Windows 10 UI, make sure you have placed the semicolons correctly. There should be exactly one separating every path in the list.

There really isn't much else to say here. Simply add the path to PATH and click OK.

Set JAVA_HOME

While you're at it, you may as well set JAVA_HOME as well. This is another environment variable that should also contain the Java path. Many Java and non-Java programs, including the popular Java build systems Maven and Gradle, will throw errors if it is not correctly set.

If JAVA_HOME does not exist, create it as a new system environment variable. Set it to the path of the Java directory without the bin/ directory, i.e. C:\Program Files\Java\jdkxxxx\.

Remember to edit JAVA_HOME after upgrading Java, too.

Close and re-open Command Prompt

Though you have modified PATH, all running programs, including cmd, only see the old PATH. This is because the list of all environment variables is only copied into a program when it begins executing; thereafter, it only consults the cached copy.

There is no good way to refresh cmd's environment variables, so simply close Command Prompt and open it again. If you are using an IDE, close and re-open it too.

See also

Make footer stick to bottom of page correctly

Use this one. It will fix it.

#ibox_footer {
    padding-top: 3px; 
    position: absolute;
    height: 20px;
    margin-bottom: 0;
    bottom: 0;
    width: 100%;
}

Save ArrayList to SharedPreferences

For String, int, boolean, the best choice would be sharedPreferences.

If you want to store ArrayList or any complex data. The best choice would be Paper library.

Add dependency

implementation 'io.paperdb:paperdb:2.6'

Initialize Paper

Should be initialized once in Application.onCreate():

Paper.init(context);

Save

List<Person> contacts = ...
Paper.book().write("contacts", contacts);

Loading Data

Use default values if object doesn't exist in the storage.

List<Person> contacts = Paper.book().read("contacts", new ArrayList<>());

Here you go.

https://github.com/pilgr/Paper

VirtualBox error "Failed to open a session for the virtual machine"

Updating VirtualBox to newest version fixed my issue.

return, return None, and no return at all?

In terms of functionality these are all the same, the difference between them is in code readability and style (which is important to consider)

Passing an array as an argument to a function in C

In C, except for a few special cases, an array reference always "decays" to a pointer to the first element of the array. Therefore, it isn't possible to pass an array "by value". An array in a function call will be passed to the function as a pointer, which is analogous to passing the array by reference.

EDIT: There are three such special cases where an array does not decay to a pointer to it's first element:

  1. sizeof a is not the same as sizeof (&a[0]).
  2. &a is not the same as &(&a[0]) (and not quite the same as &a[0]).
  3. char b[] = "foo" is not the same as char b[] = &("foo").

Git pull - Please move or remove them before you can merge

I just faced the same issue and solved it using the following.First clear tracked files by using :

git clean -d -f

then try git pull origin master

You can view other git clean options by typing git clean -help

get basic SQL Server table structure information

Instead of using count(*) you can SELECT * and you will return all of the details that you want including data_type:

SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'Address'

MSDN Docs on INFORMATION_SCHEMA.COLUMNS

Appending values to dictionary in Python

You should use append to add to the list. But also here are few code tips:

I would use dict.setdefault or defaultdict to avoid having to specify the empty list in the dictionary definition.

If you use prev to to filter out duplicated values you can simplfy the code using groupby from itertools Your code with the amendments looks as follows:

import itertools
def make_drug_dictionary(data):
    drug_dictionary = {}
    for key, row in itertools.groupby(data, lambda x: x[11]):
        drug_dictionary.setdefault(key,[]).append(row[?])
    return drug_dictionary

If you don't know how groupby works just check this example:

>>> list(key for key, val in itertools.groupby('aaabbccddeefaa'))
['a', 'b', 'c', 'd', 'e', 'f', 'a']

MessageBox with YesNoCancel - No & Cancel triggers same event

Closing conformation alert:

Private Sub cmd_exit_click()

    ' By clicking on the button the MsgBox will appear
    If MsgBox("Are you sure want to exit now?", MsgBoxStyle.YesNo, "closing warning") = MsgBoxResult.Yes Then ' If you select yes in the MsgBox then it will close the window
               Me.Close() ' Close the window
    Else
        ' Will not close the application
    End If
End Sub

How do I create a sequence in MySQL?

If You need sth different than AUTO_INCREMENT you can still use triggers.

Handlebars.js Else If

Hello I have only a MINOR classname edit, and so far this is how iv divulged it. i think i need to pass in multpile parameters to the helper,

server.js

app.engine('handlebars', ViewEngine({
        "helpers":{
                isActive: (val, options)=>{
                    if (val === 3 || val === 0){
                        return options.fn(this)
                    }
                } 
        }
}));

header.handlebars

<ul class="navlist">
          <li   class="navitem navlink {{#isActive 0}}active{{/isActive}}"
                ><a href="#">Home</a></li>
          <li   class="navitem navlink {{#isActive 1}}active{{/isActive}}"
                ><a href="#">Trending</a></li>
          <li   class="navitem navlink {{#isActive 2}}active{{/isActive}}"
                ><a href="#">People</a></li>
          <li   class="navitem navlink {{#isActive 3}}active{{/isActive}}"
                ><a href="#">Mystery</a></li>
          <li class="navitem navbar-search">
            <input type="text" id="navbar-search-input" placeholder="Search...">
            <button type="button" id="navbar-search-button"><i class="fas fa-search"></i></button>
          </li>
        </ul>

how to write an array to a file Java

You can use the ObjectOutputStream class to write objects to an underlying stream.

outputStream = new ObjectOutputStream(new FileOutputStream(filename));
outputStream.writeObject(x);

And read the Object back like -

inputStream = new ObjectInputStream(new FileInputStream(filename));
x = (int[])inputStream.readObject()

Getting attributes of Enum's value

This is how I solved it without using custom helpers or extensions with .NET core 3.1.

Class

public enum YourEnum
{
    [Display(Name = "Suryoye means Arameans")]
    SURYOYE = 0,
    [Display(Name = "Oromoye means Syriacs")]
    OROMOYE = 1,
}

Razor

@using Enumerations

foreach (var name in Html.GetEnumSelectList(typeof(YourEnum)))
{
    <h1>@name.Text</h1>
}

Servlet Mapping using web.xml

It allows servlets to have multiple servlet mappings:

<servlet>
    <servlet-name>Servlet1</servlet-name>
    <servlet-path>foo.Servlet</servlet-path>
</servlet>
<servlet-mapping>
    <servlet-name>Servlet1</servlet-name>
    <url-pattern>/enroll</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>Servlet1</servlet-name>
    <url-pattern>/pay</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>Servlet1</servlet-name>
    <url-pattern>/bill</url-pattern>
</servlet-mapping>

It allows filters to be mapped on the particular servlet:

<filter-mapping>
    <filter-name>Filter1</filter-name>
    <servlet-name>Servlet1</servlet-name>
</filter-mapping>

Your proposal would support neither of them. Note that the web.xml is read and parsed only once during application's startup, not on every HTTP request as you seem to think.

Since Servlet 3.0, there's the @WebServlet annotation which minimizes this boilerplate:

@WebServlet("/enroll")
public class Servlet1 extends HttpServlet {

See also:

Using 'make' on OS X

@Daniel's suggestion worked perfectly for me. To install

make
, open Xcode, go to Preferences -> Downloads -> Components -> Command Line Tools.You can then test with
gcc -v

How to output a multiline string in Bash?

Since I recommended printf in a comment, I should probably give some examples of its usage (although for printing a usage message, I'd be more likely to use Dennis' or Chris' answers). printf is a bit more complex to use than echo. Its first argument is a format string, in which escapes (like \n) are always interpreted; it can also contain format directives starting with %, which control where and how any additional arguments are included in it. Here are two different approaches to using it for a usage message:

First, you could include the entire message in the format string:

printf "usage: up [--level <n>| -n <levels>][--help][--version]\n\nReport bugs to: \nup home page: \n"

Note that unlike echo, you must include the final newline explicitly. Also, if the message happens to contain any % characters, they would have to be written as %%. If you wanted to include the bugreport and homepage addresses, they can be added quite naturally:

printf "usage: up [--level <n>| -n <levels>][--help][--version]\n\nReport bugs to: %s\nup home page: %s\n" "$bugreport" "$homepage"

Second, you could just use the format string to make it print each additional argument on a separate line:

printf "%s\n" "usage: up [--level <n>| -n <levels>][--help][--version]" "" "Report bugs to: " "up home page: "

With this option, adding the bugreport and homepage addresses is fairly obvious:

printf "%s\n" "usage: up [--level <n>| -n <levels>][--help][--version]" "" "Report bugs to: $bugreport" "up home page: $homepage"

Connect to SQL Server Database from PowerShell

The answer are as below for Window authentication

$SqlConnection = New-Object System.Data.SqlClient.SqlConnection
$SqlConnection.ConnectionString = "Server=$SQLServer;Database=$SQLDBName;Integrated Security=True;"

How do you get a query string on Flask?

I came here looking for the query string, not how to get values from the query string.

request.query_string returns the URL parameters as raw byte string (Ref 1).

Example of using request.query_string:

from flask import Flask, request

app = Flask(__name__)

@app.route('/data', methods=['GET'])
def get_query_string():
    return request.query_string

if __name__ == '__main__':
    app.run(debug=True)

Output:

query parameters in Flask route

References:

  1. Official API documentation on query_string

How to search multiple columns in MySQL?

You can use the AND or OR operators, depending on what you want the search to return.

SELECT title FROM pages WHERE my_col LIKE %$param1% AND another_col LIKE %$param2%;

Both clauses have to match for a record to be returned. Alternatively:

SELECT title FROM pages WHERE my_col LIKE %$param1% OR another_col LIKE %$param2%;

If either clause matches then the record will be returned.

For more about what you can do with MySQL SELECT queries, try the documentation.

JavaScript implementation of Gzip

I guess a generic client-side JavaScript compression implementation would be a very expensive operation in terms of processing time as opposed to transfer time of a few more HTTP packets with uncompressed payload.

Have you done any testing that would give you an idea how much time there is to save? I mean, bandwidth savings can't be what you're after, or can it?

calculating number of days between 2 columns of dates in data frame

You could find the difference between dates in columns in a data frame by using the function difftime as follows:

df$diff_in_days<- difftime(df$datevar1 ,df$datevar2 , units = c("days"))

How do I detect whether 32-bit Java is installed on x64 Windows, only looking at the filesystem and registry?

If it is not Oracle's Java, you may not be able to tell. When I install Oracle Java 64-bit, the files go into C:\Program Files\Java, but when I install a 32-bit version, they default to C:\Program Files (x86)\Java instead. Of course, the person who installed Java could have overridden those defaults.

Tomcat is not running even though JAVA_HOME path is correct

I think that your JAVA_HOME should point to

C:\Program Files\Java\jdk1.6.0_25

instead of

C:\Program Files\Java\jdk1.6.0_25\bin

That is, without the bin folder.

UPDATE

That new error appears to me if I set the JAVA_HOME with the quotes, like you did. Are you using quotation marks? If so, remove them.

How to remove unused imports in Intellij IDEA on commit?

Choose the project/module you want to remove unused import from in Project view. Then from Code menu choose Optimize imports and confirm with Run. The imports will be cleaned in whole project/module.

Retrieve column names from java.sql.ResultSet

When you need the column names, but do not want to grab entries:

PreparedStatement stmt = connection.prepareStatement("SHOW COLUMNS FROM `yourTable`");

ResultSet set = stmt.executeQuery();

//store all of the columns names
List<String> names = new ArrayList<>();
while (set.next()) { names.add(set.getString("Field")); }

NOTE: Only works with MySQL

Execute Python script via crontab

As you have mentioned it doesn't change anything.

First, you should redirect both standard input and standard error from the crontab execution like below:

*/2 * * * * /usr/bin/python /home/souza/Documets/Listener/listener.py > /tmp/listener.log 2>&1

Then you can view the file /tmp/listener.log to see if the script executed as you expected.

Second, I guess what you mean by change anything is by watching the files created by your program:

f = file('counter', 'r+w')
json_file = file('json_file_create_server.json', 'r+w')

The crontab job above won't create these file in directory /home/souza/Documets/Listener, as the cron job is not executed in this directory, and you use relative path in the program. So to create this file in directory /home/souza/Documets/Listener, the following cron job will do the trick:

*/2 * * * * cd /home/souza/Documets/Listener && /usr/bin/python listener.py > /tmp/listener.log 2>&1

Change to the working directory and execute the script from there, and then you can view the files created in place.

A circular reference was detected while serializing an object of type 'SubSonic.Schema .DatabaseColumn'.

It seems that there are circular references in your object hierarchy which is not supported by the JSON serializer. Do you need all the columns? You could pick up only the properties you need in the view:

return Json(new 
{  
    PropertyINeed1 = data.PropertyINeed1,
    PropertyINeed2 = data.PropertyINeed2
});

This will make your JSON object lighter and easier to understand. If you have many properties, AutoMapper could be used to automatically map between DTO objects and View objects.

git-upload-pack: command not found, when cloning remote Git repo

Like Johan pointed out many times its .bashrc that's needed:

ln -s .bash_profile .bashrc

How to include a child object's child object in Entity Framework 5

I ended up doing the following and it works:

return DatabaseContext.Applications
     .Include("Children.ChildRelationshipType");

How to control border height?

You could create an image of whatever height you wish, and then position that with the CSS background(-position) property like:

#somid { background: url(path/to/img.png) no-repeat center top;

Instead of center topyou can also use pixel or % like 50% 100px.

http://www.w3.org/TR/CSS2/colors.html#propdef-background-position

Reading a simple text file

In Mono For Android....

try
{
    System.IO.Stream StrIn = this.Assets.Open("MyMessage.txt");
    string Content = string.Empty;
    using (System.IO.StreamReader StrRead = new System.IO.StreamReader(StrIn))
    {
      try
      {
            Content = StrRead.ReadToEnd();
            StrRead.Close();
      }  
      catch (Exception ex) { csFunciones.MostarMsg(this, ex.Message); }
      }
          StrIn.Close();
          StrIn = null;
}
catch (Exception ex) { csFunciones.MostarMsg(this, ex.Message); }

Removing spaces from a variable input using PowerShell 4.0

You're close. You can strip the whitespace by using the replace method like this:

$answer.replace(' ','')

There needs to be no space or characters between the second set of quotes in the replace method (replacing the whitespace with nothing).

How to quickly test some javascript code?

If you want to edit some complex javascript I suggest you use JsFiddle. Alternatively, for smaller pieces of javascript you can just run it through your browser URL bar, here's an example:

javascript:alert("hello world");

And, as it was already suggested both Firebug and Chrome developer tools have Javascript console, in which you can type in your javascript to execute. So do Internet Explorer 8+, Opera, Safari and potentially other modern browsers.

SOAP request to WebService with java

When the WSDL is available, it is just two steps you need to follow to invoke that web service.

Step 1: Generate the client side source from a WSDL2Java tool

Step 2: Invoke the operation using:

YourService service = new YourServiceLocator();
Stub stub = service.getYourStub();
stub.operation();

If you look further, you will notice that the Stub class is used to invoke the service deployed at the remote location as a web service. When invoking that, your client actually generates the SOAP request and communicates. Similarly the web service sends the response as a SOAP. With the help of a tool like Wireshark, you can view the SOAP messages exchanged.

However since you have requested more explanation on the basics, I recommend you to refer here and write a web service with it's client to learn it further.

How to find the privileges and roles granted to a user in Oracle?

select * 
from ROLE_TAB_PRIVS 
where role in (
    select granted_role
    from dba_role_privs 
    where granted_role in ('ROLE1','ROLE2')
)

How to access my localhost from another PC in LAN?

Actualy you don't need an internet connection to use ip address. Each computer in LAN has an internal IP address you can discover by runing

ipconfig /all

in cmd.

You can use the ip address of the server (probabily something like 192.168.0.x or 10.0.0.x) to access the website remotely.

If you found the ip and still cannot access the website, it means WAMP is not configured to respond to that name ( what did you call me? 192.168.0.3? That's not my name. I'm Localhost ) and you have to modify ....../apache/config/httpd.conf

Listen *:80

Pip "Could not find a that satisfies the requirement"

pygame is not distributed via pip. See this link which provides windows binaries ready for installation.

  1. Install python
  2. Make sure you have python on your PATH
  3. Download the appropriate wheel from this link
  4. Install pip using this tutorial
  5. Finally, use these commands to install pygame wheel with pip

    • Python 2 (usually called pip)

      • pip install file.whl
    • Python 3 (usually called pip3)

      • pip3 install file.whl

Another tutorial for installing pygame for windows can be found here. Although the instructions are for 64bit windows, it can still be applied to 32bit

How to add reference to a method parameter in javadoc?

I guess you could write your own doclet or taglet to support this behaviour.

Taglet Overview

Doclet Overview

How to convert current date to epoch timestamp?

import time
def expires():
    '''return a UNIX style timestamp representing 5 minutes from now'''
    return int(time.time()+300)

in_array multiple values

if(empty(array_intersect([21,22,23,24], $check_with_this)) {
 print "Not found even a single element";
} else {
 print "Found an element";
}

array_intersect() returns an array containing all the values of array1 that are present in all the arguments. Note that keys are preserved.

Returns an array containing all of the values in array1 whose values exist in all of the parameters.


empty() — Determine whether a variable is empty

Returns FALSE if var exists and has a non-empty, non-zero value. Otherwise returns TRUE.

Allowed memory size of 262144 bytes exhausted (tried to allocate 24576 bytes)

I was trying to up the limit Wordpress sets on media uploads. I followed advice from some blog I’m not going to mention to raise the limit from 64MB to 2GB.

I did the following:

Created a (php.ini) file in WP ADMIN with the following integers:

upload_max_filesize = 2000MB
post_max_size = 2100MV
memory_limit = 2300MB

I immediately received this error when trying to log into my Wordpress dashboard to check if it worked:

“Allowed memory size of 262144 bytes exhausted (tried to allocate 24576 bytes)"

The above information in this chain helped me tremendously. (Stack usually does BTW)

I modified the PHP.ini file to the following:

upload_max_filesize = 2000M
post_max_size = 2100M
memory_limit = 536870912M

The major difference was only use M, not MB, and set that memory limit high.

As soon as I saved the changed the PHP.ini file, I saved it, went to login again and the login screen reappeared.

I went in and checked media uploads, ands bang:

Image showing twordpress media folder “Add New” box, with limits stated as “MAXIMUM UPLOAD FILE SIZE: 2 GB”

I haven't restarted Apache yet… but all looks good.

Thanks everyone.

Python script to copy text to clipboard

One more answer to improve on: https://stackoverflow.com/a/4203897/2804197 and https://stackoverflow.com/a/25476462/1338797 (Tkinter).

Tkinter is nice, because it's either included with Python (Windows) or easy to install (Linux), and thus requires little dependencies for the end user.

Here I have a "full-blown" example, which copies the arguments or the standard input, to clipboard, and - when not on Windows - waits for the user to close the application:

import sys

try:
    from Tkinter import Tk
except ImportError:
    # welcome to Python3
    from tkinter import Tk
    raw_input = input

r = Tk()
r.withdraw()
r.clipboard_clear()

if len(sys.argv) < 2:
    data = sys.stdin.read()
else:
    data = ' '.join(sys.argv[1:])

r.clipboard_append(data)

if sys.platform != 'win32':
    if len(sys.argv) > 1:
        raw_input('Data was copied into clipboard. Paste and press ENTER to exit...')
    else:
        # stdin already read; use GUI to exit
        print('Data was copied into clipboard. Paste, then close popup to exit...')
        r.deiconify()
        r.mainloop()
else:
    r.destroy()

This showcases:

  • importing Tk across Py2 and Py3
  • raw_input and print() compatibility
  • "unhiding" Tk root window when needed
  • waiting for exit on Linux in two different ways.

Warning: Use the 'defaultValue' or 'value' props on <select> instead of setting 'selected' on <option>

In an instance where you want to set a placeholder and not have a default value be selected, you can use this option.

      <select defaultValue={'DEFAULT'} >
        <option value="DEFAULT" disabled>Choose a salutation ...</option>
        <option value="1">Mr</option>
        <option value="2">Mrs</option>
        <option value="3">Ms</option>
        <option value="4">Miss</option>
        <option value="5">Dr</option>
      </select>

Here the user is forced to pick an option!

EDIT

If this is a controlled component

In this case unfortunately you will have to use both defaultValue and value violating React a bit. This is because react by semantics does not allow setting a disabled value as active.

 function TheSelectComponent(props){
     let currentValue = props.curentValue || "DEFAULT";
     return(
      <select value={currentValue} defaultValue={'DEFAULT'} onChange={props.onChange}>
        <option value="DEFAULT" disabled>Choose a salutation ...</option>
        <option value="1">Mr</option>
        <option value="2">Mrs</option>
        <option value="3">Ms</option>
        <option value="4">Miss</option>
        <option value="5">Dr</option>
      </select>
    )
}

converting date time to 24 hour format

Try this:

Date date=new Date("12/12/11 8:22:09 PM");    
System.out.println("Time in 24Hours ="+new SimpleDateFormat("HH:mm").format(date));

Using fonts with Rails asset pipeline

Now here's a twist:

You should place all fonts in app/assets/fonts/ as they WILL get precompiled in staging and production by default—they will get precompiled when pushed to heroku.

Font files placed in vendor/assets will NOT be precompiled on staging or production by default — they will fail on heroku. Source!

@plapier, thoughtbot/bourbon

I strongly believe that putting vendor fonts into vendor/assets/fonts makes a lot more sense than putting them into app/assets/fonts. With these 2 lines of extra configuration this has worked well for me (on Rails 4):

app.config.assets.paths << Rails.root.join('vendor', 'assets', 'fonts')  
app.config.assets.precompile << /\.(?:svg|eot|woff|ttf)$/

@jhilden, thoughtbot/bourbon

I've also tested it on rails 4.0.0. Actually the last one line is enough to safely precompile fonts from vendor folder. Took a couple of hours to figure it out. Hope it helped someone.

Add "Are you sure?" to my excel button, how can I?

On your existing button code, simply insert this line before the procedure:

If MsgBox("This will erase everything! Are you sure?", vbYesNo) = vbNo Then Exit Sub

This will force it to quit if the user presses no.

Flexbox: how to get divs to fill up 100% of the container width without wrapping?

You can use the shorthand flex property and set it to

flex: 0 0 100%;

That's flex-grow, flex-shrink, and flex-basis in one line. Flex shrink was described above, flex grow is the opposite, and flex basis is the size of the container.

Do copyright dates need to be updated?

It is important to recognize that the copyright laws have changed and that for non-US sources, especially after the USA joining the Berne Convention on March 1, 1989, copyright registration in not necessary for enforcement of a copyright notice.
Here is a resumé quoted from the Cornell University Law School (copied on March 4, 2015 from https://www.law.cornell.edu/wex/copyright:

"Copyright copyright: an overview

The U.S. Copyright Act, 17 U.S.C. §§ 101 - 810, is Federal legislation enacted by Congress under its Constitutional grant of authority to protect the writings of authors. See U.S. Constitution, Article I, Section 8. Changing technology has led to an ever expanding understanding of the word "writings." The Copyright Act now reaches architectural design, software, the graphic arts, motion pictures, and sound recordings. See § 106. As of January 1, 1978, all works of authorship fixed in a tangible medium of expression and within the subject matter of copyright were deemed to fall within the exclusive jurisdiction of the Copyright Act regardless of whether the work was created before or after that date and whether published or unpublished. See § 301. See also preemption.

The owner of a copyright has the exclusive right to reproduce, distribute, perform, display, license, and to prepare derivative works based on the copyrighted work. See § 106. The exclusive rights of the copyright owner are subject to limitation by the doctrine of "fair use." See § 107. Fair use of a copyrighted work for purposes such as criticism, comment, news reporting, teaching, scholarship, or research is not copyright infringement. To determine whether or not a particular use qualifies as fair use, courts apply a multi-factor balancing test. See § 107.

Copyright protection subsists in original works of authorship fixed in any tangible medium of expression from which they can be perceived, reproduced, or otherwise communicated, either directly or with the aid of a machine or device. See § 102. Copyright protection does not extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery. For example, if a book is written describing a new system of bookkeeping, copyright protection only extends to the author's description of the bookkeeping system; it does not protect the system itself. See Baker v. Selden, 101 U.S. 99 (1879).

According to the Copyright Act of 1976, registration of copyright is voluntary and may take place at any time during the term of protection. See § 408. Although registration of a work with the Copyright Office is not a precondition for protection, an action for copyright infringement may not be commenced until the copyright has been formally registered with the Copyright Office. See § 411.

Deposit of copies with the Copyright Office for use by the Library of Congress is a separate requirement from registration. Failure to comply with the deposit requirement within three months of publication of the protected work may result in a civil fine. See § 407. The Register of Copyrights may exempt certain categories of material from the deposit requirement.

In 1989 the U.S. joined the Berne Convention for the Protection of Literary and Artistic Works. In accordance with the requirements of the Berne Convention, notice is no longer a condition of protection for works published after March 1, 1989. This change to the notice requirement applies only prospectively to copies of works publicly distributed after March 1, 1989.

The Berne Convention also modified the rule making copyright registration a precondition to commencing a lawsuit for infringement. For works originating from a Berne Convention country, an infringement action may be initiated without registering the work with the U.S. Copyright Office. However, for works of U.S. origin, registration prior to filing suit is still required.

The federal agency charged with administering the act is the Copyright Office of the Library of Congress. See § 701 of the act. Its regulations are found in Parts 201 - 204 of title 37 of the Code of Federal Regulations."

UML diagram shapes missing on Visio 2013

If you don't see stencils creating new document with a template you may open the template directly. In my case they are located at 'C:\Program Files\Microsoft Office\Office15\Visio Content\1049\' Last foler name varies regarding locale, I guess. UML template is named 'DBUML_M.VSTX'

What killed my process and why?

We have had recurring problems under Linux at a customer site (Red Hat, I think), with OOMKiller (out-of-memory killer) killing both our principle application (i.e. the reason the server exists) and it's data base processes.

In each case OOMKiller simply decided that the processes were using to much resources... the machine wasn't even about to fail for lack of resources. Neither the application nor it's database has problems with memory leaks (or any other resource leak).

I am not a Linux expert, but I rather gathered it's algorithm for deciding when to kill something and what to kill is complex. Also, I was told (I can't speak as to the accuracy of this) that OOMKiller is baked into the Kernel and you can't simply not run it.

'this' is undefined in JavaScript class methods

This question has been answered, but maybe this might someone else coming here.

I also had an issue where this is undefined, when I was foolishly trying to destructure the methods of a class when initialising it:

import MyClass from "./myClass"

// 'this' is not defined here:
const { aMethod } = new MyClass()
aMethod() // error: 'this' is not defined

// So instead, init as you would normally:
const myClass = new MyClass()
myClass.aMethod() // OK

Proper use of 'yield return'

I tend to use yield-return when I calculate the next item in the list (or even the next group of items).

Using your Version 2, you must have the complete list before returning. By using yield-return, you really only need to have the next item before returning.

Among other things, this helps spread the computational cost of complex calculations over a larger time-frame. For example, if the list is hooked up to a GUI and the user never goes to the last page, you never calculate the final items in the list.

Another case where yield-return is preferable is if the IEnumerable represents an infinite set. Consider the list of Prime Numbers, or an infinite list of random numbers. You can never return the full IEnumerable at once, so you use yield-return to return the list incrementally.

In your particular example, you have the full list of products, so I'd use Version 2.

How do you remove Subversion control for a folder?

The answer is surprisingly simple - export the folder to itself! TortoiseSVN detects this special case and asks if you want to make the working copy unversioned. If you answer yes the control directories will be removed and you will have a plain, unversioned directory tree.

How to round float numbers in javascript?

Number((6.688689).toFixed(1)); // 6.7

var number = 6.688689;
var roundedNumber = Math.round(number * 10) / 10;

Use toFixed() function.

(6.688689).toFixed(); // equal to "7"
(6.688689).toFixed(1); // equal to "6.7"
(6.688689).toFixed(2); // equal to "6.69"

Is it safe to shallow clone with --depth 1, create commits, and pull updates again?

See some of the answers to my similar question why-cant-i-push-from-a-shallow-clone and the link to the recent thread on the git list.

Ultimately, the 'depth' measurement isn't consistent between repos, because they measure from their individual HEADs, rather than (a) your Head, or (b) the commit(s) you cloned/fetched, or (c) something else you had in mind.

The hard bit is getting one's Use Case right (i.e. self-consistent), so that distributed, and therefore probably divergent repos will still work happily together.

It does look like the checkout --orphan is the right 'set-up' stage, but still lacks clean (i.e. a simple understandable one line command) guidance on the "clone" step. Rather it looks like you have to init a repo, set up a remote tracking branch (you do want the one branch only?), and then fetch that single branch, which feels long winded with more opportunity for mistakes.

Edit: For the 'clone' step see this answer

Installing RubyGems in Windows

Installing Ruby

Go to http://rubyinstaller.org/downloads/

Make sure that you check "Add ruby ... to your PATH". enter image description here

Now you can use "ruby" in your "cmd".

If you installed ruby 1.9.3 I expect that the ruby is downloaded in C:\Ruby193.

Installing Gem

install Development Kit in rubyinstaller. Make new folder such as C:\RubyDevKit and unzip.

Go to the devkit directory and type ruby dk.rb init to generate config.yml.

If you installed devkit for 1.9.3, I expect that the config.yml will be written as C:\Ruby193.

If not, please correct path to your ruby folders.

After reviewing the config.yml, you can finally type ruby dk.rb install.

Now you can use "gem" in your "cmd". It's done!

Copying a rsa public key to clipboard

Your command is right, but the error shows that you didn't create your ssh key yet. To generate new ssh key enter the following command into the terminal.

ssh-keygen

After entering the command then you will be asked to enter file name and passphrase. Normally you don't need to change this. Just press enter. Then your key will be generated in ~/.ssh directory. After this, you can copy your key by the following command.

pbcopy < ~/.ssh/id_rsa.pub 

or

cat .ssh/id_rsa.pub | pbcopy

You can find more about this here ssh.

jQuery find parent form

I would suggest using closest, which selects the closest matching parent element:

$('input[name="submitButton"]').closest("form");

Instead of filtering by the name, I would do this:

$('input[type=submit]').closest("form");

Run a .bat file using python code

python_test.py

import subprocess
a = subprocess.check_output("batch_1.bat")
print a

This gives output from batch file to be print on the python IDLE/running console. So in batch file you can echo the result in each step to debug the issue. This is also useful in automation when there is an error happening in the batch call, to understand and locate the error easily.(put "echo off" in batch file beginning to avoid printing everything)

batch_1.bat

echo off    
echo "Hello World" 
md newdir 
echo "made new directory"

How to make inline plots in Jupyter Notebook larger?

The question is about matplotlib, but for the sake of any R users that end up here given the language-agnostic title:

If you're using an R kernel, just use:

options(repr.plot.width=4, repr.plot.height=3)

Can't create a docker image for COPY failed: stat /var/lib/docker/tmp/docker-builder error

Another potential cause is that docker will not follow symbolic links by default (i.e don't use ln -s).

How do I split a string into an array of characters?

Old question but I should warn:

Do NOT use .split('')

You'll get weird results with non-BMP (non-Basic-Multilingual-Plane) character sets.

Reason is that methods like .split() and .charCodeAt() only respect the characters with a code point below 65536; bec. higher code points are represented by a pair of (lower valued) "surrogate" pseudo-characters.

''.length     // —> 6
''.split('')  // —> ["?", "?", "?", "?", "?", "?"]

''.length      // —> 2
''.split('')   // —> ["?", "?"]

Use ES2015 (ES6) features where possible:

Using the spread operator:

let arr = [...str];

Or Array.from

let arr = Array.from(str);

Or split with the new u RegExp flag:

let arr = str.split(/(?!$)/u);

Examples:

[...'']        // —> ["", "", ""]
[...'']     // —> ["", "", ""]

For ES5, options are limited:

I came up with this function that internally uses MDN example to get the correct code point of each character.

function stringToArray() {
  var i = 0,
    arr = [],
    codePoint;
  while (!isNaN(codePoint = knownCharCodeAt(str, i))) {
    arr.push(String.fromCodePoint(codePoint));
    i++;
  }
  return arr;
}

This requires knownCharCodeAt() function and for some browsers; a String.fromCodePoint() polyfill.

if (!String.fromCodePoint) {
// ES6 Unicode Shims 0.1 , © 2012 Steven Levithan , MIT License
    String.fromCodePoint = function fromCodePoint () {
        var chars = [], point, offset, units, i;
        for (i = 0; i < arguments.length; ++i) {
            point = arguments[i];
            offset = point - 0x10000;
            units = point > 0xFFFF ? [0xD800 + (offset >> 10), 0xDC00 + (offset & 0x3FF)] : [point];
            chars.push(String.fromCharCode.apply(null, units));
        }
        return chars.join("");
    }
}

Examples:

stringToArray('')     // —> ["", "", ""]
stringToArray('')  // —> ["", "", ""]

Note: str[index] (ES5) and str.charAt(index) will also return weird results with non-BMP charsets. e.g. ''.charAt(0) returns "?".

UPDATE: Read this nice article about JS and unicode.

Android 8: Cleartext HTTP traffic not permitted

For React Native projects

It was already fixed on RN 0.59. You can find on upgrade diff from 0.58.6 to 0.59 You can apply it without upgrading you RN versionust follow the below steps:

Create files:

android/app/src/debug/res/xml/react_native_config.xml -

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
  <domain-config cleartextTrafficPermitted="true">
    <domain includeSubdomains="false">localhost</domain>
    <domain includeSubdomains="false">10.0.2.2</domain>
    <domain includeSubdomains="false">10.0.3.2</domain>
  </domain-config>
</network-security-config>

android/app/src/debug/AndroidManifest.xml -

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools">

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

  <application tools:targetApi="28"
      tools:ignore="GoogleAppIndexingWarning" 
      android:networkSecurityConfig="@xml/react_native_config" />
</manifest>

Check the accepted answer to know the root cause.

Listing all extras of an Intent

Sorry if this is too verbose or too late, but this was the only way I could find to get the job done. The most complicating factor was the fact that java does not have pass by reference functions, so the get---Extra methods need a default to return and cannot modify a boolean value to tell whether or not the default value is being returned by chance, or because the results were not favorable. For this purpose, it would have been nicer to have the method raise an exception than to have it return a default.

I found my information here: Android Intent Documentation.

    //substitute your own intent here
    Intent intent = new Intent();
    intent.putExtra("first", "hello");
    intent.putExtra("second", 1);
    intent.putExtra("third", true);
    intent.putExtra("fourth", 1.01);
    // convert the set to a string array

Set Documentation

    String[] anArray = {};
    Set<String> extras1 = (Set<String>) intent.getExtras().keySet();
    String[] extras = (String[]) extras1.toArray(anArray);
    // an arraylist to hold all of the strings
    // rather than putting strings in here, you could display them
    ArrayList<String> endResult = new ArrayList<String>();
    for (int i=0; i<extras.length; i++) {
        //try using as a String
        String aString = intent.getStringExtra(extras[i]);
        // is a string, because the default return value for a non-string is null
        if (aString != null) {
            endResult.add(extras[i] + " : " + aString);
        }
        // not a string
        else {
            // try the next data type, int
            int anInt = intent.getIntExtra(extras[i], 0);
            // is the default value signifying that either it is not an int or that it happens to be 0 
            if (anInt == 0) {
                // is an int value that happens to be 0, the same as the default value
                if (intent.getIntExtra(extras[i], 1) != 1) {
                    endResult.add(extras[i] + " : " + Integer.toString(anInt));
                }
                // not an int value
                // try double (also works for float)
                else {
                    double aDouble = intent.getDoubleExtra(extras[i], 0.0);
                    // is the same as the default value, but does not necessarily mean that it is not double
                    if (aDouble == 0.0) {
                        // just happens that it was 0.0 and is a double
                        if (intent.getDoubleExtra(extras[i], 1.0) != 1.0) {
                            endResult.add(extras[i] + " : " + Double.toString(aDouble));
                        }
                        // keep looking...
                        else {
                            // lastly check for boolean
                            boolean aBool = intent.getBooleanExtra(extras[i], false);
                            // same as default, but not necessarily not a bool (still could be a bool)
                            if (aBool == false) {
                                // it is a bool!
                                if (intent.getBooleanExtra(extras[i], true) != true) {
                                    endResult.add(extras[i] + " : " + Boolean.toString(aBool));
                                }
                                else {
                                    //well, the road ends here unless you want to add some more data types
                                }
                            }
                            // it is a bool
                            else {
                                endResult.add(extras[i] + " : " + Boolean.toString(aBool));
                            }
                        }
                    }
                    // is a double
                    else {
                        endResult.add(extras[i] + " : " + Double.toString(aDouble));
                    }
                }
            }
            // is an int value
            else {
                endResult.add(extras[i] + " : " + Integer.toString(anInt));
            }
        }
    }
    // to display at the end
    for (int i=0; i<endResult.size(); i++) {
        Toast.makeText(this, endResult.get(i), Toast.LENGTH_SHORT).show();
    }

SQL Server error on update command - "A severe error occurred on the current command"

In my case,I was using SubQuery and had a same problem. I realized that the problem is from memory leakage.

Restarting MSSQL service cause to flush tempDb resource and free huge amount of memory. so this was solve the problem.

Directory index forbidden by Options directive

Another issue that you might run into if you're running RHEL (I ran into it) is that there is a default welcome page configured with the httpd package that will override your settings, even if you put Options Indexes. The file is in /etc/httpd/conf.d/welcome.conf. See the following link for more info: http://wpapi.com/solved-issue-directory-index-forbidden-by-options-directive/

Error: No Firebase App '[DEFAULT]' has been created - call Firebase App.initializeApp()

I had a similar issue following Firebase's online guide found here.

The section heading "Initialize multiple apps" is misleading as the first example under this heading actually demonstrates how to initialize a single, default app. Here's said example:

// Initialize the default app
var defaultApp = admin.initializeApp(defaultAppConfig);

console.log(defaultApp.name);  // "[DEFAULT]"

// Retrieve services via the defaultApp variable...
var defaultAuth = defaultApp.auth();
var defaultDatabase = defaultApp.database();

// ... or use the equivalent shorthand notation
defaultAuth = admin.auth();
defaultDatabase = admin.database();

If you are migrating from the previous 2.x SDK you will have to update the way you access the database as shown above, or you will get the, No Firebase App '[DEFAULT]' error.

Google has better documentation at the following:

  1. INITIALIZE: https://firebase.google.com/docs/database/admin/start

  2. SAVE: https://firebase.google.com/docs/database/admin/save-data

  3. RETRIEVE: https://firebase.google.com/docs/database/admin/retrieve-data

How to run ssh-add on windows?

In order to run ssh-add on Windows one could install git using choco install git. The ssh-add command is recognized once C:\Program Files\Git\usr\bin has been added as a PATH variable and the command prompt has been restarted:

C:\Users\user\Desktop\repository>ssh-add .ssh/id_rsa
Enter passphrase for .ssh/id_rsa:
Identity added: .ssh/id_rsa (.ssh/id_rsa)

C:\Users\user\Desktop\repository> 

Access denied for user 'root'@'localhost' (using password: Yes) after password reset LINUX

I was able to solve this problem by executing this statement

sudo dpkg-reconfigure mysql-server-5.5

Which will change the root password.

An App ID with Identifier '' is not available. Please enter a different string

Solution for Xcode 7.3.

Go to

Member Center -> Certificates, Identifiers & Profiles -> Provisioning Profiles -> All

Member Center: https://developer.apple.com/membercenter

Find certificate for your App ID, it should be invalid, Edit, Select your iOS Distribution certificate, Generate. Go to:

Xcode -> Preferences -> Accounts -> View Details -> Download all

Invalid certificate

Generate step

SQL Server : Columns to Rows

I needed a solution to convert columns to rows in Microsoft SQL Server, without knowing the colum names (used in trigger) and without dynamic sql (dynamic sql is too slow for use in a trigger).

I finally found this solution, which works fine:

SELECT
    insRowTbl.PK,
    insRowTbl.Username,
    attr.insRow.value('local-name(.)', 'nvarchar(128)') as FieldName,
    attr.insRow.value('.', 'nvarchar(max)') as FieldValue 
FROM ( Select      
          i.ID as PK,
          i.LastModifiedBy as Username,
          convert(xml, (select i.* for xml raw)) as insRowCol
       FROM inserted as i
     ) as insRowTbl
CROSS APPLY insRowTbl.insRowCol.nodes('/row/@*') as attr(insRow)

As you can see, I convert the row into XML (Subquery select i,* for xml raw, this converts all columns into one xml column)

Then I CROSS APPLY a function to each XML attribute of this column, so that I get one row per attribute.

Overall, this converts columns into rows, without knowing the column names and without using dynamic sql. It is fast enough for my purpose.

(Edit: I just saw Roman Pekar answer above, who is doing the same. I used the dynamic sql trigger with cursors first, which was 10 to 100 times slower than this solution, but maybe it was caused by the cursor, not by the dynamic sql. Anyway, this solution is very simple an universal, so its definitively an option).

I am leaving this comment at this place, because I want to reference this explanation in my post about the full audit trigger, that you can find here: https://stackoverflow.com/a/43800286/4160788

What is the best way to test for an empty string in Go?

Both styles are used within the Go's standard libraries.

if len(s) > 0 { ... }

can be found in the strconv package: http://golang.org/src/pkg/strconv/atoi.go

if s != "" { ... }

can be found in the encoding/json package: http://golang.org/src/pkg/encoding/json/encode.go

Both are idiomatic and are clear enough. It is more a matter of personal taste and about clarity.

Russ Cox writes in a golang-nuts thread:

The one that makes the code clear.
If I'm about to look at element x I typically write
len(s) > x, even for x == 0, but if I care about
"is it this specific string" I tend to write s == "".

It's reasonable to assume that a mature compiler will compile
len(s) == 0 and s == "" into the same, efficient code.
...

Make the code clear.

As pointed out in Timmmm's answer, the Go compiler does generate identical code in both cases.

Can I force a page break in HTML printing?

I needed a page break after every 3rd row while we use print command on browser.

I added

<div style='page-break-before: always;'></div>

after every 3rd row and my parent div have display: flex; so I removed display: flex; and it was working as I want.

Find first and last day for previous calendar month in SQL Server Reporting Services (VB.Net)

Dim thisMonth As New DateTime(DateTime.Today.Year, DateTime.Today.Month, 1)
Dim firstDayLastMonth As DateTime
Dim lastDayLastMonth As DateTime

firstDayLastMonth = thisMonth.AddMonths(-1)
lastDayLastMonth = thisMonth.AddDays(-1)

Remove last specific character in a string c#

Dim psValue As String = "1,5,12,34,123,12"
psValue = psValue.Substring(0, psValue.LastIndexOf(","))

output:

1,5,12,34,123

Sum the digits of a number

Found this on one of the problem solving challenge websites. Not mine, but it works.

num = 0            # replace 0 with whatever number you want to sum up
print(sum([int(k) for k in str(num)]))

How do I disable the security certificate check in Python requests

To add to Blender's answer, you can disable SSL certificate validation for all requests using Session.verify = False

import requests

session = requests.Session()
session.verify = False
session.post(url='https://example.com', data={'bar':'baz'})

Note that urllib3, (which Requests uses), strongly discourages making unverified HTTPS requests and will raise an InsecureRequestWarning.

Hibernate Union alternatives

You could use id in (select id from ...) or id in (select id from ...)

e.g. instead of non-working

from Person p where p.name="Joe"
union
from Person p join p.children c where c.name="Joe"

you could do

from Person p 
  where p.id in (select p1.id from Person p1 where p1.name="Joe") 
    or p.id in (select p2.id from Person p2 join p2.children c where c.name="Joe");

At least using MySQL, you will run into performance problems with it later, though. It's sometimes easier to do a poor man's join on two queries instead:

// use set for uniqueness
Set<Person> people = new HashSet<Person>((List<Person>) query1.list());
people.addAll((List<Person>) query2.list());
return new ArrayList<Person>(people);

It's often better to do two simple queries than one complex one.

EDIT:

to give an example, here is the EXPLAIN output of the resulting MySQL query from the subselect solution:

mysql> explain 
  select p.* from PERSON p 
    where p.id in (select p1.id from PERSON p1 where p1.name = "Joe") 
      or p.id in (select p2.id from PERSON p2 
        join CHILDREN c on p2.id = c.parent where c.name="Joe") \G
*************************** 1. row ***************************
           id: 1
  select_type: PRIMARY
        table: a
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: 247554
        Extra: Using where
*************************** 2. row ***************************
           id: 3
  select_type: DEPENDENT SUBQUERY
        table: NULL
         type: NULL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: NULL
        Extra: Impossible WHERE noticed after reading const tables
*************************** 3. row ***************************
           id: 2
  select_type: DEPENDENT SUBQUERY
        table: a1
         type: unique_subquery
possible_keys: PRIMARY,name,sortname
          key: PRIMARY
      key_len: 4
          ref: func
         rows: 1
        Extra: Using where
3 rows in set (0.00 sec)

Most importantly, 1. row doesn't use any index and considers 200k+ rows. Bad! Execution of this query took 0.7s wheres both subqueries are in the milliseconds.

Disable pasting text into HTML form

Hope below code will work :

<!--Disable Copy And Paste-->
<script language='JavaScript1.2'>
function disableselect(e){
return false
}
function reEnable(){
return true
}
document.onselectstart=new Function ("return false")
if (window.sidebar){
document.onmousedown=disableselect
document.onclick=reEnable
}
</script>

Difference between two dates in years, months, days in JavaScript

Yet another solution, based on some PHP code. The strtotime function, also based on PHP, can be found here: http://phpjs.org/functions/strtotime/.

Date.dateDiff = function(d1, d2) {
    d1 /= 1000;
    d2 /= 1000;
    if (d1 > d2) d2 = [d1, d1 = d2][0];

    var diffs = {
        year: 0,
        month: 0,
        day: 0,
        hour: 0,
        minute: 0,
        second: 0
    }

    $.each(diffs, function(interval) {
        while (d2 >= (d3 = Date.strtotime('+1 '+interval, d1))) {
            d1 = d3;
            ++diffs[interval];
        }
    });

    return diffs;
};

Usage:

> d1 = new Date(2000, 0, 1)
Sat Jan 01 2000 00:00:00 GMT+0100 (CET)

> d2 = new Date(2013, 9, 6)
Sun Oct 06 2013 00:00:00 GMT+0200 (CEST)

> Date.dateDiff(d1, d2)
Object {
  day: 5
  hour: 0
  minute: 0
  month: 9
  second: 0
  year: 13
}

Angular 2 Dropdown Options Default Value

Add on to @Matthijs 's answer, please make sure your select element has a name attribute and its name is unique in your html template. Angular 2 is using input name to update changes. Thus, if there are duplicated names or there is no name attached to input element, the binding will fail.

how to change attribute "hidden" in jquery

A. Wolff was leading you in the right direction. There are several attributes where you should not be setting a string value. You must toggle it with a boolean true or false.

.attr("hidden", false) will remove the attribute the same as using .removeAttr("hidden").

.attr("hidden", "false") is incorrect and the tag remains hidden.

You should not be setting hidden, checked, selected, or several others to any string value to toggle it.

How to show particular image as thumbnail while implementing share on Facebook?

Here’s how this works all:

  1. You need the ability to access the HTML on the particular webpage you are sharing. It'll probably work site wide too if you use a common header file. I have not tried this, but it should work. You'll just get the same image for all pages if you do this though.

  2. You need to add these HTML meta tags into page in the . It will not work if you put it in the . Make sure to customize per your a) image, b) description, c) URL, and d) title.

A Real Example.

<meta property="og:image" content="http://www.coachesneedsocial.com/wp-content/uploads/2014/12/BannerWCircleImages-1.jpg" />

<meta property="og:description" content="Coaches share their secrets to success so you can rock 2015." />

<meta property="og:url"content="http://www.coachesneedsocial.com/coacheswisdomtelesummit/" />

<meta property="og:title" content="Coaches Wisdom Telesummit" />
  1. Save
  2. Open a fresh Facebook post, and retry the page you wanted to share.
  3. If you are having trouble… you can debug it with this Facebook tool. It looks more geeky than it is. It tells you what Facebook is seeing when you post in the URL to share.

https://developers.facebook.com/tools/debug/og/object/

Big Tip.. make sure the “quote marks” are the same in your HTML (they should look like 2 straight marks and no curves… sometimes programs change these to different fonts and it goofs up the code.

How to divide two columns?

Presumably, those columns are integer columns - which will be the reason as the result of the calculation will be of the same type.

e.g. if you do this:

SELECT 1 / 2

you will get 0, which is obviously not the real answer. So, convert the values to e.g. decimal and do the calculation based on that datatype instead.

e.g.

SELECT CAST(1 AS DECIMAL) / 2

gives 0.500000

Increase max_execution_time in PHP?

For increasing execution time and file size, you need to mention below values in your .htaccess file. It will work.

php_value upload_max_filesize 80M
php_value post_max_size 80M
php_value max_input_time 18000
php_value max_execution_time 18000

Get ID of element that called a function

For others unexpectedly getting the Window element, a common pitfall:

<a href="javascript:myfunction(this)">click here</a>

which actually scopes this to the Window object. Instead:

<a href="javascript:nop()" onclick="myfunction(this)">click here</a>

passes the a object as expected. (nop() is just any empty function.)

Div not expanding even with content inside

You have a fixed height on .infohold, so the .albumhold div will only add up to the height of .infohold (20px) + .albumpic (110px) plus any padding or margin which I haven't included there.

Try removing the fixed height on .infohold and see what happens.

asynchronous vs non-blocking

Blocking: control returns to invoking precess after processing of primitive(sync or async) completes

Non blocking: control returns to process immediately after invocation

Why are my CSS3 media queries not working on mobile devices?

Don't forget to have the standard css declarations above the media query or the query won't work either.

.edcar_letter{
    font-size:180px;
}

@media screen and (max-width: 350px) {
    .edcar_letter{
        font-size:120px;
    }
}

Set focus on textbox in WPF

txtCompanyID.Focusable = true;
Keyboard.Focus(txtCompanyID);

msdn:

There can be only one element on the whole desktop that has keyboard focus. In WPF, the element that has keyboard focus will have IsKeyboardFocused set to true.

You could break after the setting line and check the value of IsKeyboardFocused property. Also check if you really reach that line or maybe you set some other element to get focus after that.

Valid characters of a hostname?

If you're registering a domain and the termination (ex .com) it is not IDN, as Aaron Hathaway said: Hostnames are composed of series of labels concatenated with dots, as are all domain names. For example, en.wikipedia.org is a hostname. Each label must be between 1 and 63 characters long, and the entire hostname (including the delimiting dots but not a trailing dot) has a maximum of 253 ASCII characters.

The Internet standards (Requests for Comments) for protocols mandate that component hostname labels may contain only the ASCII letters a through z (in a case-insensitive manner), the digits 0 through 9, and the hyphen -. The original specification of hostnames in RFC 952, mandated that labels could not start with a digit or with a hyphen, and must not end with a hyphen. However, a subsequent specification (RFC 1123) permitted hostname labels to start with digits. No other symbols, punctuation characters, or white space are permitted.

Later, Spain with it's .es, .com.es, .org.es, .nom,es, .gob.es and .edu.es introduced IDN tlds, if your tld is one of .es or any other that supports it, any character can be used, but you can't combine alphabets like Latin, Greek or Cyril in one hostname, and that it respects the things that can't go at the start or at the end.

If you're using non-registered tlds, just for local networking, like with local DNS or with hosts files, you can treat them all as IDN.

Keep in mind some programs could not work well, especially old, outdated and unpopular ones.

GLYPHICONS - bootstrap icon font hex value

If you want to use glyph icons with bootstrap 2.3.2, Add the font files from bootstrap 3 to your project folder then copy this to your css file

 @font-face {
  font-family: 'Glyphicons Halflings';
  src: url('../fonts/glyphicons-halflings-regular.eot');
  src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'), url('../fonts/glyphicons-halflings-regular.woff') format('woff'), url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'), url('../fonts/glyphicons-halflings-regular.svg#glyphicons-halflingsregular') format('svg');
}

CSS media query to target iPad and iPad only?

<html>
<head>
    <title>orientation and device detection in css3</title>

    <link rel="stylesheet" media="all and (max-device-width: 480px) and (orientation:portrait)" href="iphone-portrait.css" />
    <link rel="stylesheet" media="all and (max-device-width: 480px) and (orientation:landscape)" href="iphone-landscape.css" />
    <link rel="stylesheet" media="all and (device-width: 768px) and (device-height: 1024px) and (orientation:portrait)" href="ipad-portrait.css" />
    <link rel="stylesheet" media="all and (device-width: 768px) and (device-height: 1024px) and (orientation:landscape)" href="ipad-landscape.css" />
    <link rel="stylesheet" media="all and (device-width: 800px) and (device-height: 1184px) and (orientation:portrait)" href="htcdesire-portrait.css" />
    <link rel="stylesheet" media="all and (device-width: 800px) and (device-height: 390px) and (orientation:landscape)" href="htcdesire-landscape.css" />
    <link rel="stylesheet" media="all and (min-device-width: 1025px)" href="desktop.css" />

</head>
<body>
    <div id="iphonelandscape">iphone landscape</div>
    <div id="iphoneportrait">iphone portrait</div>
    <div id="ipadlandscape">ipad landscape</div>
    <div id="ipadportrait">ipad portrait</div>
    <div id="htcdesirelandscape">htc desire landscape</div>
    <div id="htcdesireportrait">htc desire portrait</div>
    <div id="desktop">desktop</div>
    <script type="text/javascript">
        function res() { document.write(screen.width + ', ' + screen.height); }
        res();
    </script>
</body>
</html>

Checking if an input field is required using jQuery

The required property is boolean:

$('form#register').find('input').each(function(){
    if(!$(this).prop('required')){
        console.log("NR");
    } else {
        console.log("IR");
    }
});

Reference: HTMLInputElement

Find if variable is divisible by 2

if (x & 1)
 itIsOddNumber();
else
 itIsEvenNumber();

How can I test a PDF document if it is PDF/A compliant?

Do you have Adobe PDFL or Acrobat Professional? You can use preflight operation if you do.

Max tcp/ip connections on Windows Server 2008

How many thousands of users?

I've run some TCP/IP client/server connection tests in the past on Windows 2003 Server and managed more than 70,000 connections on a reasonably low spec VM. (see here for details: http://www.lenholgate.com/blog/2005/10/the-64000-connection-question.html). I would be extremely surprised if Windows 2008 Server is limited to less than 2003 Server and, IMHO, the posting that Cloud links to is too vague to be much use. This kind of question comes up a lot, I blogged about why I don't really think that it's something that you should actually worry about here: http://www.serverframework.com/asynchronousevents/2010/12/one-million-tcp-connections.html.

Personally I'd test it and see. Even if there is no inherent limit in the Windows 2008 Server version that you intend to use there will still be practical limits based on memory, processor speed and server design.

If you want to run some 'generic' tests you can use my multi-client connection test and the associated echo server. Detailed here: http://www.lenholgate.com/blog/2005/11/windows-tcpip-server-performance.html and here: http://www.lenholgate.com/blog/2005/11/simple-echo-servers.html. These are what I used to run my own tests for my server framework and these are what allowed me to create 70,000 active connections on a Windows 2003 Server VM with 760MB of memory.

Edited to add details from the comment below...

If you're already thinking of multiple servers I'd take the following approach.

  1. Use the free tools that I link to and prove to yourself that you can create a reasonable number of connections onto your target OS (beware of the Windows limits on dynamic ports which may cause your client connections to fail, search for MAX_USER_PORT).

  2. during development regularly test your actual server with test clients that can create connections and actually 'do something' on the server. This will help to prevent you building the server in ways that restrict its scalability. See here: http://www.serverframework.com/asynchronousevents/2010/10/how-to-support-10000-or-more-concurrent-tcp-connections-part-2-perf-tests-from-day-0.html

How to name and retrieve a stash by name in git?

Stashes are not meant to be permanent things like you want. You'd probably be better served using tags on commits. Construct the thing you want to stash. Make a commit out of it. Create a tag for that commit. Then roll back your branch to HEAD^. Now when you want to reapply that stash you can use git cherry-pick -n tagname (-n is --no-commit).

Stretch child div height to fill parent that has dynamic height

Add the following CSS:

For the parent div:

style="display: flex;"

For child div:

style="align-items: stretch;"

Construct a manual legend for a complicated plot

In case you were struggling to change linetypes, the following answer should be helpful. (This is an addition to the solution by Andy W.)

We will try to extend the learned pattern:

cols <- c("LINE1"="#f04546","LINE2"="#3591d1","BAR"="#62c76b")
line_types <- c("LINE1"=1,"LINE2"=3)
ggplot(data=data,aes(x=a)) + 
  geom_bar(stat="identity", aes(y=h,fill = "BAR"))+ #green
  geom_line(aes(y=b,group=1, colour="LINE1", linetype="LINE1"),size=0.5) +   #red
  geom_point(aes(y=b, colour="LINE1", fill="LINE1"),size=2) +           #red
  geom_line(aes(y=c,group=1,colour="LINE2", linetype="LINE2"),size=0.5) +   #blue 
  geom_point(aes(y=c,colour="LINE2", fill="LINE2"),size=2) +           #blue
  scale_colour_manual(name="Error Bars",values=cols, 
                  guide = guide_legend(override.aes=aes(fill=NA))) + 
  scale_linetype_manual(values=line_types)+
  scale_fill_manual(name="Bar",values=cols, guide="none") +
  ylab("Symptom severity") + xlab("PHQ-9 symptoms") +
  ylim(0,1.6) +
  theme_bw() +
  theme(axis.title.x = element_text(size = 15, vjust=-.2)) +
  theme(axis.title.y = element_text(size = 15, vjust=0.3))

However, what we get is the following result: manual without name

The problem is that the linetype is not merged in the main legend. Note that we did not give any name to the method scale_linetype_manual. The trick which works here is to give it the same name as what you used for naming scale_colour_manual. More specifically, if we change the corresponding line to the following we get the desired result:

scale_linetype_manual(name="Error Bars",values=line_types)

manual with the same name

Now, it is easy to change the size of the line with the same idea.

Note that the geom_bar has not colour property anymore. (I did not try to fix this issue.) Also, adding geom_errorbar with colour attribute spoils the result. It would be great if somebody can come up with a better solution which resolves these two issues as well.

Make .gitignore ignore everything except a few files

# ignore these
*
# except foo
!foo

Create an enum with string values

There a lot of answers, but I don't see any complete solutions. The problem with the accepted answer, as well as enum { this, one }, is that it disperses the string value you happen to be using through many files. I don't really like the "update" either, it's complex and doesn't leverage types as well. I think Michael Bromley's answer is most correct, but it's interface is a bit of a hassle and could do with a type.

I am using TypeScript 2.0.+ ... Here's what I would do

export type Greeting = "hello" | "world";
export const Greeting : { hello: Greeting , world: Greeting } = {
    hello: "hello",
    world: "world"
};

Then use like this:

let greet: Greeting = Greeting.hello

It also has much nicer type / hover-over information when using a helpful IDE. The draw back is you have to write the strings twice, but at least it's only in two places.

Basic authentication for REST API using spring restTemplate

Taken from the example on this site, I think this would be the most natural way of doing it, by filling in the header value and passing the header to the template.

This is to fill in the header Authorization:

String plainCreds = "willie:p@ssword";
byte[] plainCredsBytes = plainCreds.getBytes();
byte[] base64CredsBytes = Base64.encodeBase64(plainCredsBytes);
String base64Creds = new String(base64CredsBytes);

HttpHeaders headers = new HttpHeaders();
headers.add("Authorization", "Basic " + base64Creds);

And this is to pass the header to the REST template:

HttpEntity<String> request = new HttpEntity<String>(headers);
ResponseEntity<Account> response = restTemplate.exchange(url, HttpMethod.GET, request, Account.class);
Account account = response.getBody();

DeprecationWarning: Buffer() is deprecated due to security and usability issues when I move my script to another server

var userPasswordString = new Buffer(baseAuth, 'base64').toString('ascii');

Change this line from your code to this -

var userPasswordString = Buffer.from(baseAuth, 'base64').toString('ascii');

or in my case, I gave the encoding in reverse order

var userPasswordString = Buffer.from(baseAuth, 'utf-8').toString('base64');

latex tabular width the same as the textwidth

The tabularx package gives you

  1. the total width as a first parameter, and
  2. a new column type X, all X columns will grow to fill up the total width.

For your example:

\usepackage{tabularx}
% ...    
\begin{document}
% ...

\begin{tabularx}{\textwidth}{|X|X|X|}
\hline
Input & Output& Action return \\
\hline
\hline
DNF &  simulation & jsp\\
\hline
\end{tabularx}

Iterate through a HashMap

for (Map.Entry<String, String> item : hashMap.entrySet()) {
    String key = item.getKey();
    String value = item.getValue();
}

Error - replacement has [x] rows, data has [y]

TL;DR ...and late to the party, but that short explanation might help future googlers..

In general that error message means that the replacement doesn't fit into the corresponding column of the dataframe.

A minimal example:

df <- data.frame(a = 1:2); df$a <- 1:3

throws the error

Error in $<-.data.frame(*tmp*, a, value = 1:3) : replacement has 3 rows, data has 2

which is clear, because the vector a of df has 2 entries (rows) whilst the vector we try to replace it has 3 entries (rows).

INSTALL_FAILED_MISSING_SHARED_LIBRARY error in Android

You can solve it be running on Google API emulator.

To run on Google API emulator, open your Android SDK & AVD Manager > Available packages > Google Repos > select those Google API levels that you need to test on.

After installing them, add them as virtual device and run.

Subscript out of bounds - general definition and solution?

If this helps anybody, I encountered this while using purr::map() with a function I wrote which was something like this:

find_nearby_shops <- function(base_account) {
   states_table %>% 
        filter(state == base_account$state) %>% 
        left_join(target_locations, by = c('border_states' = 'state')) %>% 
        mutate(x_latitude = base_account$latitude,
               x_longitude = base_account$longitude) %>% 
        mutate(dist_miles = geosphere::distHaversine(p1 = cbind(longitude, latitude), 
                                                     p2 = cbind(x_longitude, x_latitude))/1609.344)
}

nearby_shop_numbers <- base_locations %>% 
    split(f = base_locations$id) %>% 
    purrr::map_df(find_nearby_shops) 

I would get this error sometimes with samples, but most times I wouldn't. The root of the problem is that some of the states in the base_locations table (PR) did not exist in the states_table, so essentially I had filtered out everything, and passed an empty table on to mutate. The moral of the story is that you may have a data issue and not (just) a code problem (so you may need to clean your data.)

Thanks for agstudy and zx8754's answers above for helping with the debug.

Insert a string at a specific index

You can do it easily with regexp in one line of code

_x000D_
_x000D_
const str = 'Hello RegExp!';_x000D_
const index = 6;_x000D_
const insert = 'Lovely ';_x000D_
    _x000D_
//'Hello RegExp!'.replace(/^(.{6})(.)/, `$1Lovely $2`);_x000D_
const res = str.replace(new RegExp(`^(.{${index}})(.)`), `$1${insert}$2`);_x000D_
    _x000D_
console.log(res);
_x000D_
_x000D_
_x000D_

"Hello Lovely RegExp!"

Detecting locked tables (locked by LOCK TABLE)

You could also get all relevant details from performance_schema:

SELECT
OBJECT_SCHEMA
,OBJECT_NAME
,GROUP_CONCAT(DISTINCT EXTERNAL_LOCK)
FROM performance_schema.table_handles 
WHERE EXTERNAL_LOCK IS NOT NULL

GROUP BY
OBJECT_SCHEMA
,OBJECT_NAME

This works similar as

show open tables WHERE In_use > 0

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

I did it easily by using this following command in cmd

runas /netonly /user:Administrator\Administrator cmd

after typing this command, you have to enter your Administrator password(if you don't know your Administrator password leave it blank and press Enter or type something, worked for me)..

JOptionPane - input dialog box program

Why to annoy the user with three different Dialog Boxes to enter things, why not do all this in one go in a single Dialog and save time, instead of testing the patience of the USER ?

You can add everything in a single Dialog, by putting all the fields on your JPanel and then adding this JPanel to your JOptionPane. Below code can clarify a bit more :

import java.awt.*;
import java.util.*;
import javax.swing.*;

public class AverageExample
{
    private double[] marks;
    private JTextField[] marksField;
    private JLabel resultLabel;

    public AverageExample()
    {
        marks = new double[3];
        marksField = new JTextField[3];
        marksField[0] = new JTextField(10);
        marksField[1] = new JTextField(10);
        marksField[2] = new JTextField(10);
    }

    private void displayGUI()
    {
        int selection = JOptionPane.showConfirmDialog(
                null, getPanel(), "Input Form : "
                                , JOptionPane.OK_CANCEL_OPTION
                                , JOptionPane.PLAIN_MESSAGE);

        if (selection == JOptionPane.OK_OPTION) 
        {
            for ( int i = 0; i < 3; i++)
            {
                marks[i] = Double.valueOf(marksField[i].getText());             
            }
            Arrays.sort(marks);
            double average = (marks[1] + marks[2]) / 2.0;
            JOptionPane.showMessageDialog(null
                    , "Average is : " + Double.toString(average)
                    , "Average : "
                    , JOptionPane.PLAIN_MESSAGE);
        }
        else if (selection == JOptionPane.CANCEL_OPTION)
        {
            // Do something here.
        }
    }

    private JPanel getPanel()
    {
        JPanel basePanel = new JPanel();
        //basePanel.setLayout(new BorderLayout(5, 5));
        basePanel.setOpaque(true);
        basePanel.setBackground(Color.BLUE.darker());

        JPanel centerPanel = new JPanel();
        centerPanel.setLayout(new GridLayout(3, 2, 5, 5));
        centerPanel.setBorder(
            BorderFactory.createEmptyBorder(5, 5, 5, 5));
        centerPanel.setOpaque(true);
        centerPanel.setBackground(Color.WHITE);

        JLabel mLabel1 = new JLabel("Enter Marks 1 : ");
        JLabel mLabel2 = new JLabel("Enter Marks 2 : ");
        JLabel mLabel3 = new JLabel("Enter Marks 3 : ");

        centerPanel.add(mLabel1);
        centerPanel.add(marksField[0]);
        centerPanel.add(mLabel2);
        centerPanel.add(marksField[1]);
        centerPanel.add(mLabel3);
        centerPanel.add(marksField[2]);

        basePanel.add(centerPanel);

        return basePanel;
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                new AverageExample().displayGUI();
            }
        });
    }
}

WAMP Server ERROR "Forbidden You don't have permission to access /phpmyadmin/ on this server."

To solve this, I opened httpd.conf and changed the following line:

Allow from 127.0.0.1

to:

Allow from 127.0.0.1 ::1

window.location.href not working

The browser is still submitting the form after your code runs.

Add return false; to the handler to prevent that.

Use child_process.execSync but keep output in console

Unless you redirect stdout and stderr as the accepted answer suggests, this is not possible with execSync or spawnSync. Without redirecting stdout and stderr those commands only return stdout and stderr when the command is completed.

To do this without redirecting stdout and stderr, you are going to need to use spawn to do this but it's pretty straight forward:

var spawn = require('child_process').spawn;

//kick off process of listing files
var child = spawn('ls', ['-l', '/']);

//spit stdout to screen
child.stdout.on('data', function (data) {   process.stdout.write(data.toString());  });

//spit stderr to screen
child.stderr.on('data', function (data) {   process.stdout.write(data.toString());  });

child.on('close', function (code) { 
    console.log("Finished with code " + code);
});

I used an ls command that recursively lists files so that you can test it quickly. Spawn takes as first argument the executable name you are trying to run and as it's second argument it takes an array of strings representing each parameter you want to pass to that executable.

However, if you are set on using execSync and can't redirect stdout or stderr for some reason, you can open up another terminal like xterm and pass it a command like so:

var execSync = require('child_process').execSync;

execSync("xterm -title RecursiveFileListing -e ls -latkR /");

This will allow you to see what your command is doing in the new terminal but still have the synchronous call.

How can I load storyboard programmatically from class?

Swift 3

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "viewController")
self.navigationController!.pushViewController(vc, animated: true)

Swift 2

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("viewController")
self.navigationController!.pushViewController(vc, animated: true)

Prerequisite

Assign a Storyboard ID to your view controller.

Storyboard ID

IB > Show the Identity inspector > Identity > Storyboard ID

Swift (legacy)

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("viewController") as? UIViewController
self.navigationController!.pushViewController(vc!, animated: true)

Edit: Swift 2 suggested in a comment by Fred A.

if you want to use without any navigationController you have to use like following :

    let Storyboard  = UIStoryboard(name: "Main", bundle: nil)
    let vc = Storyboard.instantiateViewController(withIdentifier: "viewController")
    present(vc , animated: true , completion: nil)

Convert to Datetime MM/dd/yyyy HH:mm:ss in Sql Server

use

select convert(varchar(10),GETDATE(), 103) + 
       ' '+
       right(convert(varchar(32),GETDATE(),108),8) AS Date_Time

It will Produce:

Date_Time 30/03/2015 11:51:40

HashMap get/put complexity

HashMap operation is dependent factor of hashCode implementation. For the ideal scenario lets say the good hash implementation which provide unique hash code for every object (No hash collision) then the best, worst and average case scenario would be O(1). Let's consider a scenario where a bad implementation of hashCode always returns 1 or such hash which has hash collision. In this case the time complexity would be O(n).

Now coming to the second part of the question about memory, then yes memory constraint would be taken care by JVM.

R dplyr: Drop multiple columns

If you have a special character in the column names, either select or select_may not work as expected. This property of dplyr of using ".". To refer to the data set in the question, the following line can be used to solve this problem:

drop.cols <- c('Sepal.Length', 'Sepal.Width')
  iris %>% .[,setdiff(names(.),drop.cols)]

Undefined symbols for architecture i386: _OBJC_CLASS_$_SKPSMTPMessage", referenced from: error

try this one last:

so I tried all the suggestions on this page.. none worked.. The way my problem started was by following the steps in this tutorial that teaches how to link static libraries. With my sample project the instructions worked fine.. but then on my actual project I started getting the error above.

So what I did was go through each step of the said tutorial and built after each step.. the offending line turned out to be this one: adding -all_load to build settings-> other linker flags

it turns out that this flag was recommended once upon a time to link categories to static libraries.. but then it turned out that this flag was no longer necessary Xcode 4.2+.. (same goes for the -force_load flag.. which was also recommended in other posts)..

How do I verify/check/test/validate my SSH passphrase?

If your passphrase is to unlock your SSH key and you don't have ssh-agent, but do have sshd (the SSH daemon) installed on your machine, do:

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys;
ssh localhost -i ~/.ssh/id_rsa

Where ~/.ssh/id_rsa.pub is the public key, and ~/.ssh/id_rsa is the private key.

Are the days of passing const std::string & as a parameter over?

Herb Sutter is still on record, along with Bjarne Stroustroup, in recommending const std::string& as a parameter type; see https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Rf-in .

There is a pitfall not mentioned in any of the other answers here: if you pass a string literal to a const std::string& parameter, it will pass a reference to a temporary string, created on-the-fly to hold the characters of the literal. If you then save that reference, it will be invalid once the temporary string is deallocated. To be safe, you must save a copy, not the reference. The problem stems from the fact that string literals are const char[N] types, requiring promotion to std::string.

The code below illustrates the pitfall and the workaround, along with a minor efficiency option -- overloading with a const char* method, as described at Is there a way to pass a string literal as reference in C++.

(Note: Sutter & Stroustroup advise that if you keep a copy of the string, also provide an overloaded function with a && parameter and std::move() it.)

#include <string>
#include <iostream>
class WidgetBadRef {
public:
    WidgetBadRef(const std::string& s) : myStrRef(s)  // copy the reference...
    {}

    const std::string& myStrRef;    // might be a reference to a temporary (oops!)
};

class WidgetSafeCopy {
public:
    WidgetSafeCopy(const std::string& s) : myStrCopy(s)
            // constructor for string references; copy the string
    {std::cout << "const std::string& constructor\n";}

    WidgetSafeCopy(const char* cs) : myStrCopy(cs)
            // constructor for string literals (and char arrays);
            // for minor efficiency only;
            // create the std::string directly from the chars
    {std::cout << "const char * constructor\n";}

    const std::string myStrCopy;    // save a copy, not a reference!
};

int main() {
    WidgetBadRef w1("First string");
    WidgetSafeCopy w2("Second string"); // uses the const char* constructor, no temp string
    WidgetSafeCopy w3(w2.myStrCopy);    // uses the String reference constructor
    std::cout << w1.myStrRef << "\n";   // garbage out
    std::cout << w2.myStrCopy << "\n";  // OK
    std::cout << w3.myStrCopy << "\n";  // OK
}

OUTPUT:

const char * constructor
const std::string& constructor

Second string
Second string

"Specified argument was out of the range of valid values"

I was also getting same issue as i tried using value 0 in non-based indexing,i.e starting with 1, not with zero

A component is changing an uncontrolled input of type text to be controlled error in ReactJS

Put empty value if the value does not exist or null.

value={ this.state.value || "" }

Remove Project from Android Studio

If you are trying to delete/cut as suggested by @Pacific P. Regmi and if you are getting "Folder in use" which won't let you to delete/cut make sure to close all the android studio instances.

Stopping Docker containers by image name - Ubuntu

The previous answers did not work for me, but this did:

docker stop $(docker ps -q --filter ancestor=<image-name> )

Jackson serialization: ignore empty values (or null)

I was having similar problem recently with version 2.6.6.

@JsonInclude(JsonInclude.Include.NON_NULL)

Using above annotation either on filed or class level was not working as expected. The POJO was mutable where I was applying the annotation. When I changed the behaviour of the POJO to be immutable the annotation worked its magic.

I am not sure if its down to new version or previous versions of this lib had similar behaviour but for 2.6.6 certainly you need to have Immutable POJO for the annotation to work.

objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

Above option mentioned in various answers of setting serialisation inclusion in ObjectMapper directly at global level works as well but, I prefer controlling it at class or filed level.

So if you wanted all the null fields to be ignored while JSON serialisation then use the annotation at class level but if you want only few fields to ignored in a class then use it over those specific fields. This way its more readable & easy for maintenance if you wanted to change behaviour for specific response.

Drop data frame columns by name

Out of interest, this flags up one of R's weird multiple syntax inconsistencies. For example given a two-column data frame:

df <- data.frame(x=1, y=2)

This gives a data frame

subset(df, select=-y)

but this gives a vector

df[,-2]

This is all explained in ?[ but it's not exactly expected behaviour. Well at least not to me...

printf with std::string?

It's compiling because printf isn't type safe, since it uses variable arguments in the C sense1. printf has no option for std::string, only a C-style string. Using something else in place of what it expects definitely won't give you the results you want. It's actually undefined behaviour, so anything at all could happen.

The easiest way to fix this, since you're using C++, is printing it normally with std::cout, since std::string supports that through operator overloading:

std::cout << "Follow this command: " << myString;

If, for some reason, you need to extract the C-style string, you can use the c_str() method of std::string to get a const char * that is null-terminated. Using your example:

#include <iostream>
#include <string>
#include <stdio.h>

int main()
{
    using namespace std;

    string myString = "Press ENTER to quit program!";
    cout << "Come up and C++ me some time." << endl;
    printf("Follow this command: %s", myString.c_str()); //note the use of c_str
    cin.get();

    return 0;
}

If you want a function that is like printf, but type safe, look into variadic templates (C++11, supported on all major compilers as of MSVC12). You can find an example of one here. There's nothing I know of implemented like that in the standard library, but there might be in Boost, specifically boost::format.


[1]: This means that you can pass any number of arguments, but the function relies on you to tell it the number and types of those arguments. In the case of printf, that means a string with encoded type information like %d meaning int. If you lie about the type or number, the function has no standard way of knowing, although some compilers have the ability to check and give warnings when you lie.

How to make the 'cut' command treat same sequental delimiters as one?

As you comment in your question, awk is really the way to go. To use cut is possible together with tr -s to squeeze spaces, as kev's answer shows.

Let me however go through all the possible combinations for future readers. Explanations are at the Test section.

tr | cut

tr -s ' ' < file | cut -d' ' -f4

awk

awk '{print $4}' file

bash

while read -r _ _ _ myfield _
do
   echo "forth field: $myfield"
done < file

sed

sed -r 's/^([^ ]*[ ]*){3}([^ ]*).*/\2/' file

Tests

Given this file, let's test the commands:

$ cat a
this   is    line     1 more text
this      is line    2     more text
this    is line 3     more text
this is   line 4            more    text

tr | cut

$ cut -d' ' -f4 a
is
                        # it does not show what we want!


$ tr -s ' ' < a | cut -d' ' -f4
1
2                       # this makes it!
3
4
$

awk

$ awk '{print $4}' a
1
2
3
4

bash

This reads the fields sequentially. By using _ we indicate that this is a throwaway variable as a "junk variable" to ignore these fields. This way, we store $myfield as the 4th field in the file, no matter the spaces in between them.

$ while read -r _ _ _ a _; do echo "4th field: $a"; done < a
4th field: 1
4th field: 2
4th field: 3
4th field: 4

sed

This catches three groups of spaces and no spaces with ([^ ]*[ ]*){3}. Then, it catches whatever coming until a space as the 4th field, that it is finally printed with \1.

$ sed -r 's/^([^ ]*[ ]*){3}([^ ]*).*/\2/' a
1
2
3
4

Execution failed for task :':app:mergeDebugResources'. Android Studio

I had that problem, but it was because my images changed them manually from .JPG to .PNG, so I just changed them with PNG paint and solved the problem

What is the difference between varchar and varchar2 in Oracle?

After some experimentation (see below), I can confirm that as of September 2017, nothing has changed with regards to the functionality described in the accepted answer:-

  1. Rextester demo for Oracle 11g: Empty strings are inserted as NULLs for both VARCHAR and VARCHAR2.
  2. LiveSQL demo for Oracle 12c: Same results.

The historical reason for these two keywords is explained well in an answer to a different question.

How can I scroll to a specific location on the page using jquery?

There is no need to use any plugin, you can do it like this:

var divPosition = $('#divId').offset();

then use this to scroll document to specific DOM:

$('html, body').animate({scrollTop: divPosition.top}, "slow");

How to split a python string on new line characters

a.txt

this is line 1
this is line 2

code:

Python 3.4.0 (default, Mar 20 2014, 22:43:40) 
[GCC 4.6.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> file = open('a.txt').read()
>>> file
>>> file.split('\n')
['this is line 1', 'this is line 2', '']

I'm on Linux, but I guess you just use \r\n on Windows and it would also work

How can I use NSError in my iPhone App?

I'll try summarize the great answer by Alex and the jlmendezbonini's point, adding a modification that will make everything ARC compatible (so far it's not since ARC will complain since you should return id, which means "any object", but BOOL is not an object type).

- (BOOL) endWorldHunger:(id)largeAmountsOfMonies error:(NSError**)error {
    // begin feeding the world's children...
    // it's all going well until....
    if (ohNoImOutOfMonies) {
        // sad, we can't solve world hunger, but we can let people know what went wrong!
        // init dictionary to be used to populate error object
        NSMutableDictionary* details = [NSMutableDictionary dictionary];
        [details setValue:@"ran out of money" forKey:NSLocalizedDescriptionKey];
        // populate the error object with the details
        if (error != NULL) {
             // populate the error object with the details
             *error = [NSError errorWithDomain:@"world" code:200 userInfo:details];
        }
        // we couldn't feed the world's children...return nil..sniffle...sniffle
        return NO;
    }
    // wohoo! We fed the world's children. The world is now in lots of debt. But who cares? 
    return YES;
}

Now instead of checking for the return value of our method call, we check whether error is still nil. If it's not we have a problem.

// initialize NSError object
NSError* error = nil;
// try to feed the world
BOOL success = [self endWorldHunger:smallAmountsOfMonies error:&error];
if (!success) {
   // inspect error
   NSLog(@"%@", [error localizedDescription]);
}
// otherwise the world has been fed. Wow, your code must rock.

Remove all HTMLtags in a string (with the jquery text() function)

Could you not just try it?

myContent = '<div id="test">Hello <span>world!</span></div>';
console.log($(myContent).text()); //Prints "Hello world!"

Note that you need to wrap the string in a jQuery object, otherwise it won't have a text method obviously.

java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication Maven

Clean your maven cache and rerun:

mvn dependency:purge-local-repository

Show and hide a View with a slide up/down animation

With the new animation API that was introduced in Android 3.0 (Honeycomb) it is very simple to create such animations.

Sliding a View down by a distance:

view.animate().translationY(distance);

You can later slide the View back to its original position like this:

view.animate().translationY(0);

You can also easily combine multiple animations. The following animation will slide a View down by its height and fade it in at the same time:

// Prepare the View for the animation
view.setVisibility(View.VISIBLE);
view.setAlpha(0.0f);

// Start the animation
view.animate()
    .translationY(view.getHeight())
    .alpha(1.0f)
    .setListener(null);

You can then fade the View back out and slide it back to its original position. We also set an AnimatorListener so we can set the visibility of the View back to GONE once the animation is finished:

view.animate()
    .translationY(0)
    .alpha(0.0f)
    .setListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            super.onAnimationEnd(animation);
            view.setVisibility(View.GONE);
        }
    });

Convert Promise to Observable

try this:

import 'rxjs/add/observable/fromPromise';
import { Observable } from "rxjs/Observable";

const subscription = Observable.fromPromise(
    firebase.auth().createUserWithEmailAndPassword(email, password)
);
subscription.subscribe(firebaseUser => /* Do anything with data received */,
                       error => /* Handle error here */);

you can find complete reference to fromPromise operator here.

How do you make an element "flash" in jQuery

Straight jquery, no plugins. It blinks the specified number of times, changes the background color while blinking and then changes it back.

function blink(target, count, blinkspeed, bc) {
    let promises=[];
    const b=target.css(`background-color`);
    target.css(`background-color`, bc||b);
    for (i=1; i<count; i++) {
            const blink = target.fadeTo(blinkspeed||100, .3).fadeTo(blinkspeed||100, 1.0);
            promises.push(blink);
    }
    // wait for all the blinking to finish before changing the background color back
    $.when.apply(null, promises).done(function() {
            target.css(`background-color`, b);
    });
    promises=undefined;
}

Example:

blink($(`.alert-danger`), 5, 200, `yellow`);

css to make bootstrap navbar transparent

There is no need for all this mess.

You can make the navbar transparent by not writing navbar-defaultor navbar-inverse

<nav class="navbar">  //Don't add navbar-default to the class

  //

</nav>

How can I wait for set of asynchronous callback functions?

You can emulate it like this:

  countDownLatch = {
     count: 0,
     check: function() {
         this.count--;
         if (this.count == 0) this.calculate();
     },
     calculate: function() {...}
  };

then each async call does this:

countDownLatch.count++;

while in each asynch call back at the end of the method you add this line:

countDownLatch.check();

In other words, you emulate a count-down-latch functionality.

java.util.MissingResourceException: Can't find bundle for base name 'property_file name', locale en_US

I'd like to share my experience of using Ant in building projects, *.properties files should be copied explicitly. This is because Ant will not compile *.properties files into the build working directory by default (javac just ignore *.properties). For example:

<target name="compile" depends="init">
    <javac destdir="${dst}" srcdir="${src}" debug="on" encoding="utf-8" includeantruntime="false">
        <include name="com/example/**" />
        <classpath refid="libs" />
    </javac>
    <copy todir="${dst}">
        <fileset dir="${src}" includes="**/*.properties" />
    </copy>
</target>

<target name="jars" depends="compile">
    <jar jarfile="${app_jar}" basedir="${dst}" includes="com/example/**/*.*" />
</target>

Please notice that 'copy' section under the 'compile' target, it will replicate *.properties files into the build working directory. Without the 'copy' section the jar file will not contain the properties files, then you may encounter the java.util.MissingResourceException.

Get user profile picture by Id

Through the Javascript SDK (v2.12 - April, 2017) you can get the details of the picture request this way:

FB.api("/" + uid + "/picture?redirect=0", function (response) {
  console.log(response);

  // prints the following:
  //data: {
  //  height: 50
  //  is_silhouette: false
  //  url: "https://lookaside.facebook.com/platform/profilepic/?asid=…&height=50&width=50&ext=…&hash…"
  //  width: 50
  //}

  if (response && !response.error) {
    // change the src attribute of img elements
    [...document.getElementsByClassName('fb-user-img')].forEach(
      i => i.src = response.data.url
    );

    // OR redirect to the URL above
    location.assign(response.data.url);
  }
});

For getting the JSON response the parameter redirect with 0 (zero) as value is important since the request redirects to the image by default. You may still add other parameters in the same URL. Examples:

  • "/" + uid + "/picture?redirect=0&width=100&height=100": a 100x100 image will be returned;
  • "/" + uid + "/picture?redirect=0&type=large": a 200x200 image is returned. Other possible type values include: small, normal, album, and square.

How do you follow an HTTP Redirect in Node.js?

If all you want to do is follow redirects but still want to use the built-in HTTP and HTTPS modules, I suggest you use https://github.com/follow-redirects/follow-redirects.

yarn add follow-redirects
npm install follow-redirects

All you need to do is replace:

var http = require('http');

with

var http = require('follow-redirects').http;

... and all your requests will automatically follow redirects.

With TypeScript you can also install the types

npm install @types/follow-redirects

and then use

import { http, https } from 'follow-redirects';

Disclosure: I wrote this module.

Tri-state Check box in HTML?

Here other Example with simple jQuery and property data-checked:

_x000D_
_x000D_
 $("#checkbox")_x000D_
  .click(function(e) {_x000D_
    var el = $(this);_x000D_
_x000D_
    switch (el.data('checked')) {_x000D_
_x000D_
      // unchecked, going indeterminate_x000D_
      case 0:_x000D_
        el.data('checked', 1);_x000D_
        el.prop('indeterminate', true);_x000D_
        break;_x000D_
_x000D_
        // indeterminate, going checked_x000D_
      case 1:_x000D_
        el.data('checked', 2);_x000D_
        el.prop('indeterminate', false);_x000D_
        el.prop('checked', true);_x000D_
        break;_x000D_
_x000D_
        // checked, going unchecked_x000D_
      default:_x000D_
        el.data('checked', 0);_x000D_
        el.prop('indeterminate', false);_x000D_
        el.prop('checked', false);_x000D_
_x000D_
    }_x000D_
  });
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<label><input type="checkbox" name="checkbox" value="" checked id="checkbox"> Tri-State Checkbox </label>
_x000D_
_x000D_
_x000D_

Rownum in postgresql

I have just tested in Postgres 9.1 a solution which is close to Oracle ROWNUM:

select row_number() over() as id, t.*
from information_schema.tables t;

R: Select values from data table in range

Construct some data

df <- data.frame( name=c("John", "Adam"), date=c(3, 5) )

Extract exact matches:

subset(df, date==3)

  name date
1 John    3

Extract matches in range:

subset(df, date>4 & date<6)

  name date
2 Adam    5

The following syntax produces identical results:

df[df$date>4 & df$date<6, ]

  name date
2 Adam    5

Cannot redeclare function php

Remove the function and check the output of:

var_dump(function_exists('parseDate'));

In which case, change the name of the function.

If you get false, you're including the file with that function twice, replace :

include

by

include_once

And replace :

require

by

require_once

EDIT : I'm just a little too late, post before beat me to it !

Error creating bean with name 'entityManagerFactory' defined in class path resource : Invocation of init method failed

For my case it was due to Intellij IDEA by default set Java 11 as default project SDK, but project was implemented in Java 8. I've changed "Project SDK" in File -> Project Structure -> Project (in Project Settings)

How to display binary data as image - extjs 4

The data URI format is:

data:<headers>;<encoding>,<data>

So, you need only append your data to the "data:image/jpeg;," string:

var your_binary_data = document.body.innerText.replace(/(..)/gim,'%$1'); // parse text data to URI format

window.open('data:image/jpeg;,'+your_binary_data);

Getting rid of bullet points from <ul>

The following code

_x000D_
_x000D_
#menu li{
  list-style-type: none;
}
_x000D_
<ul id="menu">
    <li>Root node 1</li>
    <li>Root node 2</li>
</ul>
_x000D_
_x000D_
_x000D_

will produce this output:

output is

sql how to cast a select query

I interpreted the question as using cast on a subquery. Yes, you can do that:

select cast((<subquery>) as <newtype>)

If you do so, then you need to be sure that the returns one row and one value. And, since it returns one value, you could put the cast in the subquery instead:

select (select cast(<val> as <newtype>) . . .)

How do I create a view controller file after creating a new view controller?

To add new ViewController once you have have an existing ViewController, follow below step:

  1. Click on background of Main.storyboard.

  2. Search and select ViewController from object library at the utility window.

  3. Drag and drop it in background to create a new ViewController.

An existing connection was forcibly closed by the remote host

Had the same bug. Actually worked in case the traffic was sent using some proxy (fiddler in my case). Updated .NET framework from 4.5.2 to >=4.6 and now everything works fine. The actual request was:
new WebClient().DownloadData("URL");
The exception was:

SocketException: An existing connection was forcibly closed by the remote host

round a single column in pandas

You are very close. You applied the round to the series of values given by df.value1. The return type is thus a Series. You need to assign that series back to the dataframe (or another dataframe with the same Index).

Also, there is a pandas.Series.round method which is basically a short hand for pandas.Series.apply(np.round).

In[2]: 
    df.value1 = df.value1.round()
    print df

Out[2]:
    item  value1  value2
    0    a       1     1.3
    1    a       2     2.5
    2    a       0     0.0
    3    b       3    -1.0
    4    b       5    -1.0

Check if MySQL table exists or not

MySQL way:

SHOW TABLES LIKE 'pattern';

There's also a deprecated PHP function for listing all db tables, take a look at http://php.net/manual/en/function.mysql-list-tables.php

Checkout that link, there are plenty of useful insight on the comments over there.

What does it mean when the size of a VARCHAR2 in Oracle is declared as 1 byte?

it means ONLY one byte will be allocated per character - so if you're using multi-byte charsets, your 1 character won't fit

if you know you have to have at least room enough for 1 character, don't use the BYTE syntax unless you know exactly how much room you'll need to store that byte

when in doubt, use VARCHAR2(1 CHAR)

same thing answered here Difference between BYTE and CHAR in column datatypes

Also, in 12c the max for varchar2 is now 32k, not 4000. If you need more than that, use CLOB

in Oracle, don't use VARCHAR

Find the greatest number in a list of numbers

You can use the inbuilt function max() with multiple arguments:

print max(1, 2, 3)

or a list:

list = [1, 2, 3]
print max(list)

or in fact anything iterable.

String to Dictionary in Python

This data is JSON! You can deserialize it using the built-in json module if you're on Python 2.6+, otherwise you can use the excellent third-party simplejson module.

import json    # or `import simplejson as json` if on Python < 2.6

json_string = u'{ "id":"123456789", ... }'
obj = json.loads(json_string)    # obj now contains a dict of the data

How to add LocalDB to Visual Studio 2015 Community's SQL Server Object Explorer?

I had the same issue today recently installing VS2015 Community Edition Update 1.

I fixed the problem by just adding the "SQL Server Data Tools" from the VS2015 setup installer... When I ran the installer the first time I selected the "Custom" installation type instead of the "Default". I wanted to see what install options were available but not select anything different than what was already ticked. My assumption was that whatever was already ticked was essentially the default install. But its not.

How to change the icon of .bat file programmatically?

If you want an icon for a batch file, first create a link for the batch file as follows

Right click in window folder where you want the link select New -> Shortcut, then specify where the .bat file is.

This creates the .lnk file you wanted. Then you can specify an icon for the link, on its properties page.

Some nice icons are available here:

%SystemRoot%\System32\SHELL32.dll

Note For me on Windows 10: %SystemRoot% == C:\Windows\

More Icons are here: C:\Windows\System32\imageres.dll

Also you might want to have the first line in the batch file to be "cd .." if you stash your batch files in a bat subdirectory one level below where your shortcuts, are supposed to execute.

How can I limit the visible options in an HTML <select> dropdown?

You can try this

_x000D_
_x000D_
<select name="select1" onmousedown="if(this.options.length>8){this.size=8;}"  onchange='this.size=0;' onblur="this.size=0;">_x000D_
             <option value="1">This is select number 1</option>_x000D_
             <option value="2">This is select number 2</option>_x000D_
             <option value="3">This is select number 3</option>_x000D_
             <option value="4">This is select number 4</option>_x000D_
             <option value="5">This is select number 5</option>_x000D_
             <option value="6">This is select number 6</option>_x000D_
             <option value="7">This is select number 7</option>_x000D_
             <option value="8">This is select number 8</option>_x000D_
             <option value="9">This is select number 9</option>_x000D_
             <option value="10">This is select number 10</option>_x000D_
             <option value="11">This is select number 11</option>_x000D_
             <option value="12">This is select number 12</option>_x000D_
           </select>
_x000D_
_x000D_
_x000D_

It worked for me

create table in postgreSQL

Replace bigint(20) not null auto_increment by bigserial not null and datetime by timestamp

Programmatically Hide/Show Android Soft Keyboard

Did you try InputMethodManager.SHOW_IMPLICIT in first window.

and for hiding in second window use InputMethodManager.HIDE_IMPLICIT_ONLY

EDIT :

If its still not working then probably you are putting it at the wrong place. Override onFinishInflate() and show/hide there.

@override
public void onFinishInflate() {
     /* code to show keyboard on startup */
    InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.showSoftInput(mUserNameEdit, InputMethodManager.SHOW_IMPLICIT);
}

The connection to adb is down, and a severe error has occurred

The connection to adb is down, and a severe error has occured.

[2011-12-19 11:45:09 - RayhReport] You must restart adb and Eclipse.
[2011-12-19 11:45:09 - RayhReport] Please ensure that adb is correctly located at 'D:\android-sdk-windows\tools\adb.exe' and can be executed.

When you go to D:\android-sdk-windows\tools\adb.exe path then you see the text file,the name of file is "adb_has_moved" thats means your adb.exe is moved to platform-tools copied down the adb.exe and paste in tools folder and run it. I'm sure it works.

Resizable table columns with jQuery

I tried to add to @user686605's work:

1) changed the cursor to col-resize at the th border

2) fixed the highlight text issue when resizing

I partially succeeded at both. Maybe someone who is better at CSS can help move this forward?

http://jsfiddle.net/telefonica/L2f7F/4/

HTML

<!--Click on th and drag...-->
<table>
    <thead>
        <tr>
            <th><div class="noCrsr">th 1</div></th>
            <th><div class="noCrsr">th 2</div></th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>td 1</td>
            <td>td 2</td>
        </tr>
    </tbody>
</table>

JS

$(function() {
    var pressed = false;
    var start = undefined;
    var startX, startWidth;

    $("table th").mousedown(function(e) {
        start = $(this);
        pressed = true;
        startX = e.pageX;
        startWidth = $(this).width();
        $(start).addClass("resizing");
        $(start).addClass("noSelect");
    });

    $(document).mousemove(function(e) {
        if(pressed) {
            $(start).width(startWidth+(e.pageX-startX));
        }
    });

    $(document).mouseup(function() {
        if(pressed) {
            $(start).removeClass("resizing");
            $(start).removeClass("noSelect");
            pressed = false;
        }
    });
});

CSS

table {
    border-width: 1px;
    border-style: solid;
    border-color: black;
    border-collapse: collapse;
}

table td {
    border-width: 1px;
    border-style: solid;
    border-color: black;
}

table th {
    border: 1px;
    border-style: solid;
    border-color: black;
    background-color: green;
    cursor: col-resize;
}

table th.resizing {
    cursor: col-resize;
}

.noCrsr {
    cursor: default;
    margin-right: +5px;
}

.noSelect {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

PHP upload image

<?php

$filename=$_FILES['file']['name'];
$filetype=$_FILES['file']['type'];
if($filetype=='image/jpeg' or $filetype=='image/png' or $filetype=='image/gif')
{
move_uploaded_file($_FILES['file']['tmp_name'],'dir_name/'.$filename);
$filepath="dir_name`enter code here`/".$filename;
}

?> 

SAP Crystal Reports runtime for .Net 4.0 (64-bit)

SAP is notoriously bad at making these downloads available... or in an easily accessible location so hopefully this link still works by the time you read this answer.

< original link no longer active >

http://scn.sap.com/docs/DOC-7824 Updated Link 2/6/13:

https://wiki.scn.sap.com/wiki/display/BOBJ/Crystal+Reports%2C+Developer+for+Visual+Studio+Downloads - "Updated 10/31/2017"

http://www.crystalreports.com/crvs/confirm/ - "Updated 10/31/2017"

Signed to unsigned conversion in C - is it always safe?

Horrible Answers Galore

Ozgur Ozcitak

When you cast from signed to unsigned (and vice versa) the internal representation of the number does not change. What changes is how the compiler interprets the sign bit.

This is completely wrong.

Mats Fredriksson

When one unsigned and one signed variable are added (or any binary operation) both are implicitly converted to unsigned, which would in this case result in a huge result.

This is also wrong. Unsigned ints may be promoted to ints should they have equal precision due to padding bits in the unsigned type.

smh

Your addition operation causes the int to be converted to an unsigned int.

Wrong. Maybe it does and maybe it doesn't.

Conversion from unsigned int to signed int is implementation dependent. (But it probably works the way you expect on most platforms these days.)

Wrong. It is either undefined behavior if it causes overflow or the value is preserved.

Anonymous

The value of i is converted to unsigned int ...

Wrong. Depends on the precision of an int relative to an unsigned int.

Taylor Price

As was previously answered, you can cast back and forth between signed and unsigned without a problem.

Wrong. Trying to store a value outside the range of a signed integer results in undefined behavior.

Now I can finally answer the question.

Should the precision of int be equal to unsigned int, u will be promoted to a signed int and you will get the value -4444 from the expression (u+i). Now, should u and i have other values, you may get overflow and undefined behavior but with those exact numbers you will get -4444 [1]. This value will have type int. But you are trying to store that value into an unsigned int so that will then be cast to an unsigned int and the value that result will end up having would be (UINT_MAX+1) - 4444.

Should the precision of unsigned int be greater than that of an int, the signed int will be promoted to an unsigned int yielding the value (UINT_MAX+1) - 5678 which will be added to the other unsigned int 1234. Should u and i have other values, which make the expression fall outside the range {0..UINT_MAX} the value (UINT_MAX+1) will either be added or subtracted until the result DOES fall inside the range {0..UINT_MAX) and no undefined behavior will occur.

What is precision?

Integers have padding bits, sign bits, and value bits. Unsigned integers do not have a sign bit obviously. Unsigned char is further guaranteed to not have padding bits. The number of values bits an integer has is how much precision it has.

[Gotchas]

The macro sizeof macro alone cannot be used to determine precision of an integer if padding bits are present. And the size of a byte does not have to be an octet (eight bits) as defined by C99.

[1] The overflow may occur at one of two points. Either before the addition (during promotion) - when you have an unsigned int which is too large to fit inside an int. The overflow may also occur after the addition even if the unsigned int was within the range of an int, after the addition the result may still overflow.