Programs & Examples On #Computability

support FragmentPagerAdapter holds reference to old fragments

Since the FragmentManager will take care of restoring your Fragments for you as soon as the onResume() method is called I have the fragment call out to the activity and add itself to a list. In my instance I am storing all of this in my PagerAdapter implementation. Each fragment knows it's position because it is added to the fragment arguments on creation. Now whenever I need to manipulate a fragment at a specific index all I have to do is use the list from my adapter.

The following is an example of an Adapter for a custom ViewPager that will grow the fragment as it moves into focus, and scale it down as it moves out of focus. Besides the Adapter and Fragment classes I have here all you need is for the parent activity to be able to reference the adapter variable and you are set.

Adapter

public class GrowPagerAdapter extends FragmentPagerAdapter implements OnPageChangeListener, OnScrollChangedListener {

public final String TAG = this.getClass().getSimpleName();

private final int COUNT = 4;

public static final float BASE_SIZE = 0.8f;
public static final float BASE_ALPHA = 0.8f;

private int mCurrentPage = 0;
private boolean mScrollingLeft;

private List<SummaryTabletFragment> mFragments;

public int getCurrentPage() {
    return mCurrentPage;
}

public void addFragment(SummaryTabletFragment fragment) {
    mFragments.add(fragment.getPosition(), fragment);
}

public GrowPagerAdapter(FragmentManager fm) {
    super(fm);

    mFragments = new ArrayList<SummaryTabletFragment>();
}

@Override
public int getCount() {
    return COUNT;
}

@Override
public Fragment getItem(int position) {
    return SummaryTabletFragment.newInstance(position);
}

@Override
public void onPageScrollStateChanged(int state) {}

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

    adjustSize(position, positionOffset);
}

@Override
public void onPageSelected(int position) {
    mCurrentPage = position;
}

/**
 * Used to adjust the size of each view in the viewpager as the user
 * scrolls.  This provides the effect of children scaling down as they
 * are moved out and back to full size as they come into focus.
 * 
 * @param position
 * @param percent
 */
private void adjustSize(int position, float percent) {

    position += (mScrollingLeft ? 1 : 0);
    int secondary = position + (mScrollingLeft ? -1 : 1);
    int tertiary = position + (mScrollingLeft ? 1 : -1);

    float scaleUp = mScrollingLeft ? percent : 1.0f - percent;
    float scaleDown = mScrollingLeft ? 1.0f - percent : percent;

    float percentOut = scaleUp > BASE_ALPHA ? BASE_ALPHA : scaleUp;
    float percentIn = scaleDown > BASE_ALPHA ? BASE_ALPHA : scaleDown;

    if (scaleUp < BASE_SIZE)
        scaleUp = BASE_SIZE;

    if (scaleDown < BASE_SIZE)
        scaleDown = BASE_SIZE;

    // Adjust the fragments that are, or will be, on screen
    SummaryTabletFragment current = (position < mFragments.size()) ? mFragments.get(position) : null;
    SummaryTabletFragment next = (secondary < mFragments.size() && secondary > -1) ? mFragments.get(secondary) : null;
    SummaryTabletFragment afterNext = (tertiary < mFragments.size() && tertiary > -1) ? mFragments.get(tertiary) : null;

    if (current != null && next != null) {

        // Apply the adjustments to each fragment
        current.transitionFragment(percentIn, scaleUp);
        next.transitionFragment(percentOut, scaleDown);

        if (afterNext != null) {
            afterNext.transitionFragment(BASE_ALPHA, BASE_SIZE);
        }
    }
}

@Override
public void onScrollChanged(int l, int t, int oldl, int oldt) {

    // Keep track of which direction we are scrolling
    mScrollingLeft = (oldl - l) < 0;
}
}

Fragment

public class SummaryTabletFragment extends BaseTabletFragment {

public final String TAG = this.getClass().getSimpleName();

private final float SCALE_SIZE = 0.8f;

private RelativeLayout mBackground, mCover;
private TextView mTitle;
private VerticalTextView mLeft, mRight;

private String mTitleText;
private Integer mColor;

private boolean mInit = false;
private Float mScale, mPercent;

private GrowPagerAdapter mAdapter;
private int mCurrentPosition = 0;

public String getTitleText() {
    return mTitleText;
}

public void setTitleText(String titleText) {
    this.mTitleText = titleText;
}

public static SummaryTabletFragment newInstance(int position) {

    SummaryTabletFragment fragment = new SummaryTabletFragment();
    fragment.setRetainInstance(true);

    Bundle args = new Bundle();
    args.putInt("position", position);
    fragment.setArguments(args);

    return fragment;
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    super.onCreateView(inflater, container, savedInstanceState);

    mRoot = inflater.inflate(R.layout.tablet_dummy_view, null);

    setupViews();
    configureView();

    return mRoot;
}

@Override
public void onViewStateRestored(Bundle savedInstanceState) {
    super.onViewStateRestored(savedInstanceState);

    if (savedInstanceState != null) {
        mColor = savedInstanceState.getInt("color", Color.BLACK);
    }

    configureView();
}

@Override
public void onSaveInstanceState(Bundle outState)  {

    outState.putInt("color", mColor);

    super.onSaveInstanceState(outState);
}

@Override
public int getPosition() {
    return getArguments().getInt("position", -1);
}

@Override
public void setPosition(int position) {
    getArguments().putInt("position", position);
}

public void onResume() {
    super.onResume();

    mAdapter = mActivity.getPagerAdapter();
    mAdapter.addFragment(this);
    mCurrentPosition = mAdapter.getCurrentPage();

    if ((getPosition() == (mCurrentPosition + 1) || getPosition() == (mCurrentPosition - 1)) && !mInit) {
        mInit = true;
        transitionFragment(GrowPagerAdapter.BASE_ALPHA, GrowPagerAdapter.BASE_SIZE);
        return;
    }

    if (getPosition() == mCurrentPosition && !mInit) {
        mInit = true;
        transitionFragment(0.00f, 1.0f);
    }
}

private void setupViews() {

    mCover = (RelativeLayout) mRoot.findViewById(R.id.cover);
    mLeft = (VerticalTextView) mRoot.findViewById(R.id.title_left);
    mRight = (VerticalTextView) mRoot.findViewById(R.id.title_right);
    mBackground = (RelativeLayout) mRoot.findViewById(R.id.root);
    mTitle = (TextView) mRoot.findViewById(R.id.title);
}

private void configureView() {

    Fonts.applyPrimaryBoldFont(mLeft, 15);
    Fonts.applyPrimaryBoldFont(mRight, 15);

    float[] size = UiUtils.getScreenMeasurements(mActivity);
    int width = (int) (size[0] * SCALE_SIZE);
    int height = (int) (size[1] * SCALE_SIZE);

    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(width, height);
    mBackground.setLayoutParams(params);

    if (mScale != null)
        transitionFragment(mPercent, mScale);

    setRandomBackground();

    setTitleText("Fragment " + getPosition());

    mTitle.setText(getTitleText().toUpperCase());
    mLeft.setText(getTitleText().toUpperCase());
    mRight.setText(getTitleText().toUpperCase());

    mLeft.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            mActivity.showNextPage();
        }
    });

    mRight.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            mActivity.showPrevPage();
        }
    });
}

private void setRandomBackground() {

    if (mColor == null) {
        Random r = new Random();
        mColor = Color.rgb(r.nextInt(255), r.nextInt(255), r.nextInt(255));
    }

    mBackground.setBackgroundColor(mColor);
}

public void transitionFragment(float percent, float scale) {

    this.mScale = scale;
    this.mPercent = percent;

    if (getView() != null && mCover != null) {

        getView().setScaleX(scale);
        getView().setScaleY(scale);

        mCover.setAlpha(percent);
        mCover.setVisibility((percent <= 0.05f) ? View.GONE : View.VISIBLE);
    }
}

@Override
public String getFragmentTitle() {
    return null;
}
}

Why can't I use background image and color together?

background:url(directoryName/imageName.extention) bottom left no-repeat; 
background-color: red;

Custom Date Format for Bootstrap-DatePicker

Perhaps you can check it here for the LATEST version always

http://bootstrap-datepicker.readthedocs.org/en/latest/

$('.datepicker').datepicker({
    format: 'mm/dd/yyyy',
    startDate: '-3d'
})

or

$.fn.datepicker.defaults.format = "mm/dd/yyyy";
$('.datepicker').datepicker({
    startDate: '-3d'
})

Selecting rows where remainder (modulo) is 1 after division by 2?

At least some versions of SQL (Oracle, Informix, DB2, ISO Standard) support:

WHERE MOD(value, 2) = 1

MySQL supports '%' as the modulus operator:

WHERE value % 2 = 1

Setting value of active workbook in Excel VBA

This is all you need

Set wbOOR = ActiveWorkbook

Laravel Advanced Wheres how to pass variable into function?

You can pass the necessary variables from the parent scope into the closure with the use keyword.

For example:

DB::table('users')->where(function ($query) use ($activated) {
    $query->where('activated', '=', $activated);
})->get();

More on that here.

EDIT (2019 update):

PHP 7.4 (will be released at November 28, 2019) introduces a shorter variation of the anonymous functions called arrow functions which makes this a bit less verbose.

An example using PHP 7.4 which is functionally nearly equivalent (see the 3rd bullet point below):

DB::table('users')->where(fn($query) => $query->where('activated', '=', $activated))->get();

Differences compared to the regular syntax:

  • fn keyword instead of function.
  • No need to explicitly list all variables which should be captured from the parent scope - this is now done automatically by-value. See the lack of use keyword in the latter example.
  • Arrow functions always return a value. This also means that it's impossible to use void return type when declaring them.
  • The return keyword must be omitted.
  • Arrow functions must have a single expression which is the return statement. Multi-line functions aren't supported at the moment. You can still chain methods though.

Put search icon near textbox using bootstrap

<input type="text" name="whatever" id="funkystyling" />

Here's the CSS for the image on the left:

#funkystyling {
    background: white url(/path/to/icon.png) left no-repeat;
    padding-left: 17px;
}

And here's the CSS for the image on the right:

#funkystyling {
    background: white url(/path/to/icon.png) right no-repeat;
    padding-right: 17px;
}

Best way to implement multi-language/globalization in large .NET project

You can use commercial tools like Sisulizer. It will create satellite assembly for each language. Only thing you should pay attention is not to obfuscate form class names (if you use obfuscator).

Looping through JSON with node.js

My most preferred way is,

var objectKeysArray = Object.keys(yourJsonObj)
objectKeysArray.forEach(function(objKey) {
    var objValue = yourJsonObj[objKey]
})

Why is the use of alloca() not considered good practice?

I don't think anyone has mentioned this: Use of alloca in a function will hinder or disable some optimizations that could otherwise be applied in the function, since the compiler cannot know the size of the function's stack frame.

For instance, a common optimization by C compilers is to eliminate use of the frame pointer within a function, frame accesses are made relative to the stack pointer instead; so there's one more register for general use. But if alloca is called within the function, the difference between sp and fp will be unknown for part of the function, so this optimization cannot be done.

Given the rarity of its use, and its shady status as a standard function, compiler designers quite possibly disable any optimization that might cause trouble with alloca, if would take more than a little effort to make it work with alloca.

UPDATE: Since variable-length local arrays have been added to C, and since these present very similar code-generation issues to the compiler as alloca, I see that 'rarity of use and shady status' does not apply to the underlying mechanism; but I would still suspect that use of either alloca or VLA tends to compromise code generation within a function that uses them. I would welcome any feedback from compiler designers.

How do I read any request header in PHP

strtolower is lacking in several of the proposed solutions, RFC2616 (HTTP/1.1) defines header fields as case-insensitive entities. The whole thing, not just the value part.

So suggestions like only parsing HTTP_ entries are wrong.

Better would be like this:

if (!function_exists('getallheaders')) {
    foreach ($_SERVER as $name => $value) {
        /* RFC2616 (HTTP/1.1) defines header fields as case-insensitive entities. */
        if (strtolower(substr($name, 0, 5)) == 'http_') {
            $headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
        }
    }
    $this->request_headers = $headers;
} else {
    $this->request_headers = getallheaders();
}

Notice the subtle differences with previous suggestions. The function here also works on php-fpm (+nginx).

Creating a zero-filled pandas data frame

You can try this:

d = pd.DataFrame(0, index=np.arange(len(data)), columns=feature_list)

How to know/change current directory in Python shell?

You can try this:

import os

current_dir = os.path.dirname(os.path.abspath(__file__))   # Can also use os.getcwd()
print(current_dir)                                         # prints(say)- D:\abc\def\ghi\jkl\mno"
new_dir = os.chdir('..\\..\\..\\')                         
print(new_dir)                                             # prints "D:\abc\def\ghi"


How can I set the initial value of Select2 when using AJAX?

https://github.com/select2/select2/issues/4272 only this solved my problem. even you set default value by option, you have to format the object, which has the text attribute and this is what you want to show in your option. so, your format function have to use || to choose the attribute which is not empty.

Fastest way to check if a string is JSON in PHP?

A simple modification to henrik's answer to touch most required possibilities.

( including " {} and [] " )

function isValidJson($string) {
    json_decode($string);
    if(json_last_error() == JSON_ERROR_NONE) {

        if( $string[0] == "{" || $string[0] == "[" ) { 
            $first = $string [0];

            if( substr($string, -1) == "}" || substr($string, -1) == "]" ) {
                $last = substr($string, -1);

                if($first == "{" && $last == "}"){
                    return true;
                }

                if($first == "[" && $last == "]"){
                    return true;
                }

                return false;

            }
            return false;
        }

        return false;
    }

    return false;

}

Disable submit button when form invalid with AngularJS

To add to this answer. I just found out that it will also break down if you use a hyphen in your form name (Angular 1.3):

So this will not work:

<form name="my-form">
    <input name="myText" type="text" ng-model="mytext" required />
    <button ng-disabled="my-form.$invalid">Save</button>
</form>

Export multiple classes in ES6 modules

@webdeb's answer didn't work for me, I hit an unexpected token error when compiling ES6 with Babel, doing named default exports.

This worked for me, however:

// Foo.js
export default Foo
...

// bundle.js
export { default as Foo } from './Foo'
export { default as Bar } from './Bar'
...

// and import somewhere..
import { Foo, Bar } from './bundle'

How do I delete files programmatically on Android?

I tested this code on Nougat emulator and it worked:

In manifest add:

<application...

    <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="${applicationId}.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/provider_paths"/>
    </provider>
</application>

Create empty xml folder in res folder and past in the provider_paths.xml:

<?xml version="1.0" encoding="utf-8"?>
 <paths xmlns:android="http://schemas.android.com/apk/res/android">
   <external-path name="external_files" path="."/>
  </paths>

Then put the next snippet into your code (for instance fragment):

File photoLcl = new File(homeDirectory + "/" + fileNameLcl);
Uri imageUriLcl = FileProvider.getUriForFile(getActivity(), 
  getActivity().getApplicationContext().getPackageName() +
    ".provider", photoLcl);
ContentResolver contentResolver = getActivity().getContentResolver();
contentResolver.delete(imageUriLcl, null, null);

How to find minimum value from vector?

std::min_element(vec.begin(), vec.end()) - for std::vector
std::min_element(v, v+n) - for array
std::min_element( std::begin(v), std::end(v) ) - added C++11 version from comment by @JamesKanze

What's the Linq to SQL equivalent to TOP or LIMIT/OFFSET?

In VB:

from m in MyTable
take 10
select m.Foo

This assumes that MyTable implements IQueryable. You may have to access that through a DataContext or some other provider.

It also assumes that Foo is a column in MyTable that gets mapped to a property name.

See http://blogs.msdn.com/vbteam/archive/2008/01/08/converting-sql-to-linq-part-7-union-top-subqueries-bill-horst.aspx for more detail.

tsc throws `TS2307: Cannot find module` for a local file

@vladima replied to this issue on GitHub:

The way the compiler resolves modules is controlled by moduleResolution option that can be either node or classic (more details and differences can be found here). If this setting is omitted the compiler treats this setting to be node if module is commonjs and classic - otherwise. In your case if you want classic module resolution strategy to be used with commonjs modules - you need to set it explicitly by using

{
    "compilerOptions": {
        "moduleResolution": "node"
    }
}

Fatal error: Call to a member function fetch_assoc() on a non-object

I happen to miss spaces in my query and this error comes.

Ex: $sql= "SELECT * FROM";
$sql .= "table1";

Though the example might look simple, when coding complex queries, the probability for this error is high. I was missing space before word "table1".

How to add footnotes to GitHub-flavoured Markdown?

Although I am not aware if it's officially documented anywhere, you can do footer notes in Github.

  1. Mark the place where you want to insert footer link with a number enclosed in square brackets, I.E. [1]

  2. On the bottom of the post, make a reference of the numbered marker and followed by a colon and the link, I.E. [1]: http://www.example.com/link1

And once you preview it, it will be rendered as numbered links in the body of the post.

How to assign Php variable value to Javascript variable?

Essentially:

<?php
//somewhere set a value
$var = "a value";
?>

<script>
// then echo it into the js/html stream
// and assign to a js variable
spge = '<?php echo $var ;?>';

// then
alert(spge);

</script>

How to get rid of punctuation using NLTK tokenizer?

I use this code to remove punctuation:

import nltk
def getTerms(sentences):
    tokens = nltk.word_tokenize(sentences)
    words = [w.lower() for w in tokens if w.isalnum()]
    print tokens
    print words

getTerms("hh, hh3h. wo shi 2 4 A . fdffdf. A&&B ")

And If you want to check whether a token is a valid English word or not, you may need PyEnchant

Tutorial:

 import enchant
 d = enchant.Dict("en_US")
 d.check("Hello")
 d.check("Helo")
 d.suggest("Helo")

Windows batch file file download from a URL

I found this VB script:

http://www.olafrv.com/?p=385

Works like a charm. Configured as a function with a very simple function call:

SaveWebBinary "http://server/file1.ext1", "C:/file2.ext2"

Originally from: http://www.ericphelps.com/scripting/samples/BinaryDownload/index.htm

Here is the full code for redundancy:

Function SaveWebBinary(strUrl, strFile) 'As Boolean
Const adTypeBinary = 1
Const adSaveCreateOverWrite = 2
Const ForWriting = 2
Dim web, varByteArray, strData, strBuffer, lngCounter, ado
    On Error Resume Next
    'Download the file with any available object
    Err.Clear
    Set web = Nothing
    Set web = CreateObject("WinHttp.WinHttpRequest.5.1")
    If web Is Nothing Then Set web = CreateObject("WinHttp.WinHttpRequest")
    If web Is Nothing Then Set web = CreateObject("MSXML2.ServerXMLHTTP")
    If web Is Nothing Then Set web = CreateObject("Microsoft.XMLHTTP")
    web.Open "GET", strURL, False
    web.Send
    If Err.Number <> 0 Then
        SaveWebBinary = False
        Set web = Nothing
        Exit Function
    End If
    If web.Status <> "200" Then
        SaveWebBinary = False
        Set web = Nothing
        Exit Function
    End If
    varByteArray = web.ResponseBody
    Set web = Nothing
    'Now save the file with any available method
    On Error Resume Next
    Set ado = Nothing
    Set ado = CreateObject("ADODB.Stream")
    If ado Is Nothing Then
        Set fs = CreateObject("Scripting.FileSystemObject")
        Set ts = fs.OpenTextFile(strFile, ForWriting, True)
        strData = ""
        strBuffer = ""
        For lngCounter = 0 to UBound(varByteArray)
            ts.Write Chr(255 And Ascb(Midb(varByteArray,lngCounter + 1, 1)))
        Next
        ts.Close
    Else
        ado.Type = adTypeBinary
        ado.Open
        ado.Write varByteArray
        ado.SaveToFile strFile, adSaveCreateOverWrite
        ado.Close
    End If
    SaveWebBinary = True
End Function

How to deal with the URISyntaxException

Coudn't imagine nothing better for
http://server.ru:8080/template/get?type=mail&format=html&key=ecm_task_assignment&label=??????????? ? ????????????&descr=????????&objectid=2231
that:

public static boolean checkForExternal(String str) {
    int length = str.length();
    for (int i = 0; i < length; i++) {
        if (str.charAt(i) > 0x7F) {
            return true;
        }
    }
    return false;
}

private static final Pattern COLON = Pattern.compile("%3A", Pattern.LITERAL);
private static final Pattern SLASH = Pattern.compile("%2F", Pattern.LITERAL);
private static final Pattern QUEST_MARK = Pattern.compile("%3F", Pattern.LITERAL);
private static final Pattern EQUAL = Pattern.compile("%3D", Pattern.LITERAL);
private static final Pattern AMP = Pattern.compile("%26", Pattern.LITERAL);

public static String encodeUrl(String url) {
    if (checkForExternal(url)) {
        try {
            String value = URLEncoder.encode(url, "UTF-8");
            value = COLON.matcher(value).replaceAll(":");
            value = SLASH.matcher(value).replaceAll("/");
            value = QUEST_MARK.matcher(value).replaceAll("?");
            value = EQUAL.matcher(value).replaceAll("=");
            return AMP.matcher(value).replaceAll("&");
        } catch (UnsupportedEncodingException e) {
            throw LOGGER.getIllegalStateException(e);
        }
    } else {
        return url;
    }
}

"for" vs "each" in Ruby

(1..4).each { |i| 


  a = 9 if i==3

  puts a 


}
#nil
#nil
#9
#nil

for i in 1..4

  a = 9 if i==3

  puts a

end
#nil
#nil
#9
#9

In 'for' loop, local variable is still lives after each loop. In 'each' loop, local variable refreshes after each loop.

How to install latest version of Node using Brew

Sometimes brew update fails on me because one package doesn't download properly. So you can just upgrade a specific library like this:

brew upgrade node

https://gist.github.com/3005832

Why does CreateProcess give error 193 (%1 is not a valid Win32 app)

Your Button2Click and Button3Click functions pass klad.xls and smimime.txt. These files most likely aren't actual executables indeed.

In order to open arbitrary files using the application associated with them, use ShellExecute

When you use 'badidea' or 'thisisunsafe' to bypass a Chrome certificate/HSTS error, does it only apply for the current site?

This is specific for each site. So if you type that once, you will only get through that site and all other sites will need a similar type-through.

It is also remembered for that site and you have to click on the padlock to reset it (so you can type it again):

enter image description here

Needless to say use of this "feature" is a bad idea and is unsafe - hence the name.

You should find out why the site is showing the error and/or stop using it until they fix it. HSTS specifically adds protections for bad certs to prevent you clicking through them. The fact it's needed suggests there is something wrong with the https connection - like the site or your connection to it has been hacked.

The chrome developers also do change this periodically. They changed it recently from badidea to thisisunsafe so everyone using badidea, suddenly stopped being able to use it. You should not depend on it. As Steffen pointed out in the comments below, it is available in the code should it change again though they now base64 encode it to make it more obscure. The last time they changed they put this comment in the commit:

Rotate the interstitial bypass keyword

The security interstitial bypass keyword hasn't changed in two years and awareness of the bypass has been increased in blogs and social media. Rotate the keyword to help prevent misuse.

I think the message from the Chrome team is clear - you should not use it. It would not surprise me if they removed it completely in future.

If you are using this when using a self-signed certificate for local testing then why not just add your self-signed certificate certificate to your computer's certificate store so you get a green padlock and do not have to type this? Note Chrome insists on a SAN field in certificates now so if just using the old subject field then even adding it to the certificate store will not result in a green padlock.

If you leave the certificate untrusted then certain things do not work. Caching for example is completely ignored for untrusted certificates. As is HTTP/2 Push.

HTTPS is here to stay and we need to get used to using it properly - and not bypassing the warnings with a hack that is liable to change and doesn't work the same as a full HTTPS solution.

Pretty Printing JSON with React

const getJsonIndented = (obj) => JSON.stringify(newObj, null, 4).replace(/["{[,\}\]]/g, "")

const JSONDisplayer = ({children}) => (
    <div>
        <pre>{getJsonIndented(children)}</pre>
    </div>
)

Then you can easily use it:

const Demo = (props) => {
   ....
   return <JSONDisplayer>{someObj}<JSONDisplayer>
}

Create a new txt file using VB.NET

You can try writing into the Documents folder. Here is a "debug" function I did for the debugging needs of my project:

Private Sub writeDebug(ByVal x As String)
    Dim path As String = System.Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
    Dim FILE_NAME As String = path & "\mydebug.txt"
    MsgBox(FILE_NAME)
    If System.IO.File.Exists(FILE_NAME) = False Then
        System.IO.File.Create(FILE_NAME).Dispose()
    End If
    Dim objWriter As New System.IO.StreamWriter(FILE_NAME, True)
    objWriter.WriteLine(x)
    objWriter.Close()
End Sub

There are more standard folders you can access through the "SpecialFolder" object.

Entity Framework: table without primary key

EF does not require a primary key on the database. If it did, you couldn't bind entities to views.

You can modify the SSDL (and the CSDL) to specify a unique field as your primary key. If you don't have a unique field, then I believe you are hosed. But you really should have a unique field (and a PK), otherwise you are going to run into problems later.

Erick

What does the "undefined reference to varName" in C mean?

You're getting a linker error, so your extern is working (the compiler compiled a.c without a problem), but when it went to link the object files together at the end it couldn't resolve your extern -- void doSomething(int); wasn't actually found anywhere. Did you mess up the extern? Make sure there's actually a doSomething defined in b.c that takes an int and returns void, and make sure you remembered to include b.c in your file list (i.e. you're doing something like gcc a.c b.c, not just gcc a.c)

What is the OAuth 2.0 Bearer Token exactly?

A bearer token is like a currency note e.g 100$ bill . One can use the currency note without being asked any/many questions.

Bearer Token A security token with the property that any party in possession of the token (a "bearer") can use the token in any way that any other party in possession of it can. Using a bearer token does not require a bearer to prove possession of cryptographic key material (proof-of-possession).

How do I commit case-sensitive only filename changes in Git?

Using SourceTree I was able to do this all from the UI

  1. Rename FILE.ext to whatever.ext
  2. Stage that file
  3. Now rename whatever.ext to file.ext
  4. Stage that file again

It's a bit tedious, but if you only need to do it to a few files it's pretty quick

How are iloc and loc different?

iloc works based on integer positioning. So no matter what your row labels are, you can always, e.g., get the first row by doing

df.iloc[0]

or the last five rows by doing

df.iloc[-5:]

You can also use it on the columns. This retrieves the 3rd column:

df.iloc[:, 2]    # the : in the first position indicates all rows

You can combine them to get intersections of rows and columns:

df.iloc[:3, :3] # The upper-left 3 X 3 entries (assuming df has 3+ rows and columns)

On the other hand, .loc use named indices. Let's set up a data frame with strings as row and column labels:

df = pd.DataFrame(index=['a', 'b', 'c'], columns=['time', 'date', 'name'])

Then we can get the first row by

df.loc['a']     # equivalent to df.iloc[0]

and the second two rows of the 'date' column by

df.loc['b':, 'date']   # equivalent to df.iloc[1:, 1]

and so on. Now, it's probably worth pointing out that the default row and column indices for a DataFrame are integers from 0 and in this case iloc and loc would work in the same way. This is why your three examples are equivalent. If you had a non-numeric index such as strings or datetimes, df.loc[:5] would raise an error.

Also, you can do column retrieval just by using the data frame's __getitem__:

df['time']    # equivalent to df.loc[:, 'time']

Now suppose you want to mix position and named indexing, that is, indexing using names on rows and positions on columns (to clarify, I mean select from our data frame, rather than creating a data frame with strings in the row index and integers in the column index). This is where .ix comes in:

df.ix[:2, 'time']    # the first two rows of the 'time' column

I think it's also worth mentioning that you can pass boolean vectors to the loc method as well. For example:

 b = [True, False, True]
 df.loc[b] 

Will return the 1st and 3rd rows of df. This is equivalent to df[b] for selection, but it can also be used for assigning via boolean vectors:

df.loc[b, 'name'] = 'Mary', 'John'

add title attribute from css

Quentin is correct, it can't be done with CSS. If you want to add a title attribute, you can do it with JavaScript. Here's an example using jQuery:

$('label').attr('title','mandatory');

What is the current choice for doing RPC in Python?

XML-RPC is part of the Python standard library:

Merge two HTML table cells

use colspan for do this

 <td colspan="3">PUR mix up column</td>

JAX-WS and BASIC authentication, when user names and passwords are in a database

I was face-off a similar situation, I need to provide to my WS: Username, Password and WSS Password Type.

I was initially using the "Http Basic Auth" (as @ahoge), I tried to use the @Philipp-Dev 's ref. too. I didn't get a success solution.

After a little deep search at google, I found this post:

https://stackoverflow.com/a/3117841/1223901

And there was my problem solution

I hope this can help to anyone else, like helps to me.

Rgds, iVieL

Pandas DataFrame to List of Lists

I wanted to preserve the index, so I adapted the original answer to this solution:

list_df = df.reset_index().values.tolist()

Now you can paste it somewhere else (e.g. to paste into a Stack Overflow question) and latter recreate it:

pd.Dataframe(list_df, columns=['name1', ...])
pd.set_index(['name1'], inplace=True)

Route [login] not defined

Try to add this at Header of your request: Accept=application/json postman or insomnia add header

Git - How to close commit editor?

I had this problem I received a ">" like prompt and I couldn't commit. I replace the " in the comment with ' and it works.

I hope this help someone!

how to get selected row value in the KendoUI

I think it needs to be checked if any row is selected or not? The below code would check it:

var entityGrid = $("#EntitesGrid").data("kendoGrid");
            var selectedItem = entityGrid.dataItem(entityGrid.select());
            if (selectedItem != undefined)
                alert("The Row Is SELECTED");
            else
                alert("NO Row Is SELECTED")

Split and join C# string

You can split and join the string, but why not use substrings? Then you only end up with one split instead of splitting the string into 5 parts and re-joining it. The end result is the same, but the substring is probably a bit faster.

string lcStart = "Some Very Large String Here";
int lnSpace = lcStart.IndexOf(' ');

if (lnSpace > -1)
{
    string lcFirst = lcStart.Substring(0, lnSpace);
    string lcRest = lcStart.Substring(lnSpace + 1);
}

Strangest language feature

The concatenation in Tcl is adding two strings it become one string:

set s1 "prime"
set s2 "number"
set s3 $s1$s2
puts s3

The output is

primenumber

Removing unwanted table cell borders with CSS

add some css:

td, th {
   border:none;
}

How to align flexbox columns left and right?

I came up with 4 methods to achieve the results. Here is demo

Method 1:

#a {
    margin-right: auto;
}

Method 2:

#a {
    flex-grow: 1;
}

Method 3:

#b {
    margin-left: auto;
}

Method 4:

#container {
    justify-content: space-between;
}

The type or namespace name 'Entity' does not exist in the namespace 'System.Data'

I had just updated my Entity framework to version 6 in my Visual studio 2013 through NugetPackage and add following References:

System.Data.Entity,
System.Data.Entity.Design,
System.Data.Linq

by right clicking on references->Add references in my project. Now delete my previously created Entity model and recreate it again,Built solution. Now It works fine for me.

In Powershell what is the idiomatic way of converting a string to an int?

Using .net

[int]$b = $null #used after as refence
$b
0
[int32]::TryParse($a , [ref]$b ) # test if is possible to cast and put parsed value in reference variable
True
$b
10
$b.gettype()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Int32                                    System.ValueType

note this (powershell coercing feature)

$a = "10"
$a + 1 #second value is evaluated as [string]
101 

11 + $a # second value is evaluated as [int]
21

How to export MySQL database with triggers and procedures?

May be it's obvious for expert users of MYSQL but I wasted some time while trying to figure out default value would not export functions. So I thought to mention here that --routines param needs to be set to true to make it work.

mysqldump --routines=true -u <user> my_database > my_database.sql

How to do sed like text replace with python?

You could do something like:

p = re.compile("^\# *deb", re.MULTILINE)
text = open("sources.list", "r").read()
f = open("sources.list", "w")
f.write(p.sub("deb", text))
f.close()

Alternatively (imho, this is better from organizational standpoint) you could split your sources.list into pieces (one entry/one repository) and place them under /etc/apt/sources.list.d/

Visual studio equivalent of java System.out

Or, if you want to see output in the Output window of Visual Studio, System.Diagnostics.Debug.WriteLine(stuff)

onKeyPress Vs. onKeyUp and onKeyDown

Most of the answers here are focused more on theory than practical matters and there's some big differences between keyup and keypress as it pertains to input field values, at least in Firefox (tested in 43).

If the user types 1 into an empty input element:

  1. The value of the input element will be an empty string (old value) inside the keypress handler

  2. The value of the input element will be 1 (new value) inside the keyup handler.

This is of critical importance if you are doing something that relies on knowing the new value after the input rather than the current value such as inline validation or auto tabbing.

Scenario:

  1. The user types 12345 into an input element.
  2. The user selects the text 12345.
  3. The user types the letter A.

When the keypress event fires after entering the letter A, the text box now contains only the letter A.

But:

  1. Field.val() is 12345.
  2. $Field.val().length is 5
  3. The user selection is an empty string (preventing you from determining what was deleted by overwriting the selection).

So it seems that the browser (Firefox 43) erases the user's selection, then fires the keypress event, then updates the fields contents, then fires keyup.

Jenkins "Console Output" log location in filesystem

Log location:

${JENKINS_HOME}/jobs/${JOB_NAME}/builds/${BUILD_NUMBER}/log

Get log as a text and save to workspace:

cat ${JENKINS_HOME}/jobs/${JOB_NAME}/builds/${BUILD_NUMBER}/log >> log.txt

How can I tell AngularJS to "refresh"

The solution was to call...

$scope.$apply();

...in my jQuery event callback.

C# Encoding a text string with line breaks

Yes - it means you're using \n as the line break instead of \r\n. Notepad only understands the latter.

(Note that Environment.NewLine suggested by others is fine if you want the platform default - but if you're serving from Mono and definitely want \r\n, you should specify it explicitly.)

Firefox "ssl_error_no_cypher_overlap" error

"Error code: ssl_error_no_cypher_overlap" error message after login, when Welcome screen expected--using Firefox browser

Solution

Enable support for 40-bit RSA encryption in the Firefox Browser: 1: enter 'about:config' in Browser Address bar 2: find/select "security.ssl3.rsa_rc4_40_md5" 3: set boolean to TRUE

T-SQL STOP or ABORT command in SQL Server

No, there isn't one - you have a couple of options:

  1. Wrap the whole script in a big if/end block that is simply ensured to not be true (i.e. "if 1=2 begin" - this will only work however if the script doesn't include any GO statements (as those indicate a new batch)

  2. Use the return statement at the top (again, limited by the batch separators)

  3. Use a connection based approach, which will ensure non-execution for the entire script (entire connection to be more accurate) - use something like a 'SET PARSEONLY ON' or 'SET NOEXEC ON' at the top of the script. This will ensure all statements in the connection (or until said set statement is turned off) will not execute and will instead be parsed/compiled only.

  4. Use a comment block to comment out the entire script (i.e. /* and */)

EDIT: Demonstration that the 'return' statement is batch specific - note that you will continue to see result-sets after the returns:

select 1
return
go
select 2
return
select 3
go
select 4
return
select 5
select 6
go

How do I type a TAB character in PowerShell?

If it helps you can embed a tab character in a double quoted string:

PS> "`t hello"

Why aren't variable-length arrays part of the C++ standard?

There are situations where allocating heap memory is very expensive compared to the operations performed. An example is matrix math. If you work with smallish matrices say 5 to 10 elements and do a lot of arithmetics the malloc overhead will be really significant. At the same time making the size a compile time constant does seem very wasteful and inflexible.

I think that C++ is so unsafe in itself that the argument to "try to not add more unsafe features" is not very strong. On the other hand, as C++ is arguably the most runtime efficient programming language features which makes it more so are always useful: People who write performance critical programs will to a large extent use C++, and they need as much performance as possible. Moving stuff from heap to stack is one such possibility. Reducing the number of heap blocks is another. Allowing VLAs as object members would one way to achieve this. I'm working on such a suggestion. It is a bit complicated to implement, admittedly, but it seems quite doable.

force client disconnect from server with socket.io and nodejs

This didn't work for me:

`socket.disconnect()` 

This did work for me:

socket.disconnect(true)

Handing over true will close the underlaying connection to the client and not just the namespace the client is connected to Socket IO Documentation.


An example use case: Client did connect to web socket server with invalid access token (access token handed over to web socket server with connection params). Web socket server notifies the client that it is going to close the connection, because of his invalid access token:

// (1) the server code emits
socket.emit('invalidAccessToken', function(data) {
    console.log(data);       // (4) server receives 'invalidAccessTokenEmitReceived' from client
    socket.disconnect(true); // (5) force disconnect client 
});

// (2) the client code listens to event
// client.on('invalidAccessToken', (name, fn) => { 
//     // (3) the client ack emits to server
//     fn('invalidAccessTokenEmitReceived');
// });

What does java.lang.Thread.interrupt() do?

If the targeted thread has been waiting (by calling wait(), or some other related methods that essentially do the same thing, such as sleep()), it will be interrupted, meaning that it stops waiting for what it was waiting for and receive an InterruptedException instead.

It is completely up to the thread itself (the code that called wait()) to decide what to do in this situation. It does not automatically terminate the thread.

It is sometimes used in combination with a termination flag. When interrupted, the thread could check this flag, and then shut itself down. But again, this is just a convention.

"installation of package 'FILE_PATH' had non-zero exit status" in R

I have had the same problem with a specific package in R and the solution was I should install in the ubuntu terminal libcurl. Look at the information that appears above explaining to us that curl package has error installation.

I knew this about the message:

Configuration failed because libcurl was not found. Try installing:
 * deb: libcurl4-openssl-dev (Debian, Ubuntu, etc)
 * rpm: libcurl-devel (Fedora, CentOS, RHEL)
 * csw: libcurl_dev (Solaris)
If libcurl is already installed, check that 'pkg-config' is in your
PATH and PKG_CONFIG_PATH contains a libcurl.pc file. If pkg-config
is unavailable you can set INCLUDE_DIR and LIB_DIR manually via:
R CMD INSTALL --configure-vars='INCLUDE_DIR=... LIB_DIR=...'

To install it I used the net command:

sudo apt-get install libcurl4-openssl-dev

Sometimes we can not install a specific package in R because we have problems with packages that must be installed previously as curl package. To know if we should install it we should check the warning errors such as: installation of package ‘curl’ had non-zero exit status.

I hope I have been helpful

.htaccess rewrite to redirect root URL to subdirectory

This will try the subdir if the file doesn't exist in the root. Needed this as I moved a basic .html website that expects to be ran at the root level and pushed it to a subdir. Only works if all files are flat (no .htaccess trickery in the subdir possible). Useful for linked things like css and js files.

# Internal Redirect to subdir if file is found there.
RewriteEngine on
RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_URI} !-s
RewriteCond %{DOCUMENT_ROOT}/subdir/%{REQUEST_URI} -s
RewriteRule ^(.*)$ /subdir/$1 [L]

Replacing last character in a String with java

Modify the code as fieldName = fieldName.replace("," , " ");

Cordova : Requirements check failed for JDK 1.8 or greater

I'm using windows and having two jdk 1.8 and 14 version something ...

Faced same issue and after some debugging find the solution.

  1. set JAVA_HOME correctly.
  2. Change the user variable PATH value with new jdk (1.8) version.
  3. Change the user variable PATH value with new jdk (1.8) version.

And it solved

The iOS Simulator deployment targets is set to 7.0, but the range of supported deployment target version for this platform is 8.0 to 12.1

for cordova developers having this issue

try to set

<preference name="deployment-target" value="8.0" />

in confix.xml

Java Interfaces/Implementation naming convention

Name your Interface what it is. Truck. Not ITruck because it isn't an ITruck it is a Truck.

An Interface in Java is a Type. Then you have DumpTruck, TransferTruck, WreckerTruck, CementTruck, etc that implement Truck.

When you are using the Interface in place of a sub-class you just cast it to Truck. As in List<Truck>. Putting I in front is just Hungarian style notation tautology that adds nothing but more stuff to type to your code.

All modern Java IDE's mark Interfaces and Implementations and what not without this silly notation. Don't call it TruckClass that is tautology just as bad as the IInterface tautology.

If it is an implementation it is a class. The only real exception to this rule, and there are always exceptions, could be something like AbstractTruck. Since only the sub-classes will ever see this and you should never cast to an Abstract class it does add some information that the class is abstract and to how it should be used. You could still come up with a better name than AbstractTruck and use BaseTruck or DefaultTruck instead since the abstract is in the definition. But since Abstract classes should never be part of any public facing interface I believe it is an acceptable exception to the rule. Making the constructors protected goes a long way to crossing this divide.

And the Impl suffix is just more noise as well. More tautology. Anything that isn't an interface is an implementation, even abstract classes which are partial implementations. Are you going to put that silly Impl suffix on every name of every Class?

The Interface is a contract on what the public methods and properties have to support, it is also Type information as well. Everything that implements Truck is a Type of Truck.

Look to the Java standard library itself. Do you see IList, ArrayListImpl, LinkedListImpl? No, you see List and ArrayList, and LinkedList. Here is a nice article about this exact question. Any of these silly prefix/suffix naming conventions all violate the DRY principle as well.

Also, if you find yourself adding DTO, JDO, BEAN or other silly repetitive suffixes to objects then they probably belong in a package instead of all those suffixes. Properly packaged namespaces are self documenting and reduce all the useless redundant information in these really poorly conceived proprietary naming schemes that most places don't even internally adhere to in a consistent manner.

If all you can come up with to make your Class name unique is suffixing it with Impl, then you need to rethink having an Interface at all. So when you have a situation where you have an Interface and a single Implementation that is not uniquely specialized from the Interface you probably don't need the Interface.

How to pass optional parameters while omitting some other optional parameters?

As specified in the documentation, use undefined:

export interface INotificationService {
    error(message: string, title?: string, autoHideAfter? : number);
}

class X {
    error(message: string, title?: string, autoHideAfter?: number) {
        console.log(message, title, autoHideAfter);
    }
}

new X().error("hi there", undefined, 1000);

Playground link.

Do I need to pass the full path of a file in another directory to open()?

If you are just looking for the files in a single directory (ie you are not trying to traverse a directory tree, which it doesn't look like), why not simply use os.listdir():

import os  
for fn in os.listdir('.'):
     if os.path.isfile(fn):
        print (fn)

in place of os.walk(). You can specify a directory path as a parameter for os.listdir(). os.path.isfile() will determine if the given filename is for a file.

What is the difference between MacVim and regular Vim?

It's all about the key bindings which one can simply achieve from .vimrc configurations. As far as clipboard is concerned you can use :set clipboard unnamed and the yank from vim will go to system clipboard. Anyways, whichever one you end up using I suggest using this vimrc config , it contains a whole lot of plugins and bindings which will make your experience smooth.

How to change FontSize By JavaScript?

Please never do this in real projects:

_x000D_
_x000D_
document.getElementById("span").innerHTML = "String".fontsize(25);
_x000D_
<span id="span"></span>
_x000D_
_x000D_
_x000D_

Package opencv was not found in the pkg-config search path

Hi first of all i would like you to use 'Synaptic Package Manager'. You just need to goto the ubuntu software center and search for synaptic package manager.. The beauty of this is that all the packages you need are easily available here. Second it will automatically configures all your paths. Now install this then search for opencv packages over there if you found the package with the green box then its installed but else the package is not in the right place so you need to reinstall it but from package manager this time. If installed then you can do this only, you just need to fill the OpenCV_DIR variable with the path of opencv (containing the OpenCVConfig.cmake file)

    export OpenCV_DIR=<path_of_opencv>

How to handle ListView click in Android

The two answers before mine are correct - you can use OnItemClickListener.

It's good to note that the difference between OnItemClickListener and OnItemSelectedListener, while sounding subtle, is in fact significant, as item selection and focus are related with the touch mode of your AdapterView.

By default, in touch mode, there is no selection and focus. You can take a look here for further info on the subject.

Setting background color for a JFrame

You can use this code block for JFrame background color.

    JFrame frame = new JFrame("Frame BG color");
    frame.setLayout(null);
    
    frame.setSize(1000, 650);
    frame.getContentPane().setBackground(new Color(5, 65, 90));
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.setVisible(true);

How to align entire html body to the center?

Just write

<body>
   <center>
            *Your Code Here*
   </center></body>

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

The problem is the std namespace you are missing. cout is in the std namespace.
Add using namespace std; after the #include

How do I serialize a C# anonymous type to a JSON string?

Please note this is from 2008. Today I would argue that the serializer should be built in and that you can probably use swagger + attributes to inform consumers about your endpoint and return data.


Iwould argue that you shouldn't be serializing an anonymous type. I know the temptation here; you want to quickly generate some throw-away types that are just going to be used in a loosely type environment aka Javascript in the browser. Still, I would create an actual type and decorate it as Serializable. Then you can strongly type your web methods. While this doesn't matter one iota for Javascript, it does add some self-documentation to the method. Any reasonably experienced programmer will be able to look at the function signature and say, "Oh, this is type Foo! I know how that should look in JSON."

Having said that, you might try JSON.Net to do the serialization. I have no idea if it will work

Delete item from array and shrink array

without using the System.arraycopy method you can delete an element from an array with the following

    int i = 0;
    int x = 0;
    while(i < oldArray.length){
        if(oldArray[i] == 3)i++;

        intArray[x] = oldArray[i];
        i++;
        x++;
    }

where 3 is the value you want to remove.

Understanding Python super() with __init__() methods

The main difference is that ChildA.__init__ will unconditionally call Base.__init__ whereas ChildB.__init__ will call __init__ in whatever class happens to be ChildB ancestor in self's line of ancestors (which may differ from what you expect).

If you add a ClassC that uses multiple inheritance:

class Mixin(Base):
  def __init__(self):
    print "Mixin stuff"
    super(Mixin, self).__init__()

class ChildC(ChildB, Mixin):  # Mixin is now between ChildB and Base
  pass

ChildC()
help(ChildC) # shows that the Method Resolution Order is ChildC->ChildB->Mixin->Base

then Base is no longer the parent of ChildB for ChildC instances. Now super(ChildB, self) will point to Mixin if self is a ChildC instance.

You have inserted Mixin in between ChildB and Base. And you can take advantage of it with super()

So if you are designed your classes so that they can be used in a Cooperative Multiple Inheritance scenario, you use super because you don't really know who is going to be the ancestor at runtime.

The super considered super post and pycon 2015 accompanying video explain this pretty well.

Pylint "unresolved import" error in Visual Studio Code

Alternative way: use the command interface!

Cmd/Ctrl + Shift + P ? Python: Select Interpreter ? choose the one with the packages you look for:

Enter image description here

How do I get the value of a textbox using jQuery?

There's a .val() method:

If you've got an input with an id of txtEmail you can use the following code to access the value of the text box:

$("#txtEmail").val()

You can also use the val(string) method to set that value:

$("#txtEmail").val("something")

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

Try this

<div id="divRegister"></div>

$(document).ready(function() {
location.hash = "divRegister";
});

Bootstrap 3.0 Sliding Menu from left

I believe that although javascript is an option here, you have a smoother animation through forcing hardware accelerate with CSS3. You can achieve this by setting the following CSS3 properties on the moving div:

div.hardware-accelarate {
     -webkit-transform: translate3d(0,0,0);
        -moz-transform: translate3d(0,0,0);
         -ms-transform: translate3d(0,0,0);
          -o-transform: translate3d(0,0,0);
             transform: translate3d(0,0,0);
}

I've made a plunkr setup for ya'll to test and tweak...

Where can I download an offline installer of Cygwin?

I'm not a big fan of Cygwin. It is good if you have some Unix code that requires a full POSIX system, I suppose. Even then, using it renders your programs GPL (due to the GPLed DLL), unless you pay Red Hat for a different license.

Most people should be using MinGW (and MSYS) instead. This gives you the Unix shell and utilities (even compilers, if you want them) without the purposely infectious DLL. Most of the folks using GNU compilers on Windows are using MinGW (although some don't realise it).

Just as importantly for your purposes, you can download the parts separately, rather than use the re-downloading installer.

The SourceForge download page is here. I'd suggest starting with the MSYS Base System package, which will give you the coreutils, Bash, make, tar, etc. If there's other stuff you need, you can pick and choose from the list of packages.

How to check encoding of a CSV file

Use chardet https://github.com/chardet/chardet (documentation is short and easy to read).

Install python, then pip install chardet, at last use the command line command.

I tested under GB2312 and it's pretty accurate. (Make sure you have at least a few characters, sample with only 1 character may fail easily).

file is not reliable as you can see.

enter image description here

What is the best open-source java charting library? (other than jfreechart)

I found this framework: jensoft sw2d, free for non commercial use (dual licensing)

http://www.jensoft.org

regards.

Android Get Current timestamp?

You can get Current timestamp in Android by trying below code

time.setText(String.valueOf(System.currentTimeMillis()));

and timeStamp to time format

SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
String dateString = formatter.format(new Date(Long.parseLong(time.getText().toString())));
time.setText(dateString);

How can I output leading zeros in Ruby?

Use the % operator with a string:

irb(main):001:0> "%03d" % 5
=> "005"

The left-hand-side is a printf format string, and the right-hand side can be a list of values, so you could do something like:

irb(main):002:0> filename = "%s/%s.%04d.txt" % ["dirname", "filename", 23]
=> "dirname/filename.0023.txt"

Here's a printf format cheat sheet you might find useful in forming your format string. The printf format is originally from the C function printf, but similar formating functions are available in perl, ruby, python, java, php, etc.

Postgresql - change the size of a varchar column to lower length

I was facing the same problem trying to truncate a VARCHAR from 32 to 8 and getting the ERROR: value too long for type character varying(8). I want to stay as close to SQL as possible because I'm using a self-made JPA-like structure that we might have to switch to different DBMS according to customer's choices (PostgreSQL being the default one). Hence, I don't want to use the trick of altering System tables.

I ended using the USING statement in the ALTER TABLE:

ALTER TABLE "MY_TABLE" ALTER COLUMN "MyColumn" TYPE varchar(8)
USING substr("MyColumn", 1, 8)

As @raylu noted, ALTER acquires an exclusive lock on the table so all other operations will be delayed until it completes.

How to hide TabPage from TabControl

// inVisible
TabPage page2 = tabControl1.TabPages[0];
page2.Visible= false;
//Visible 
page2.Visible= true;
// disable
TabPage page2 = tabControl1.TabPages[0];
page2.Enabled = false;
// enable
page2.Enabled = true;
//Hide
tabCtrlTagInfo.TabPages(0).Hide()
tabCtrlTagInfo.TabPages(0).Show()

Just copy paste and try it,the above code has been tested in vs2010, it works.

Android Activity without ActionBar

It's Really Simple Just go to your styles.xml change the parent Theme to either Theme.AppCompat.Light.NoActionBar or Theme.AppCompat.NoActionbar and you are done.. :)

Git merge error "commit is not possible because you have unmerged files"

If you have fixed the conflicts you need to add the files to the stage with git add [filename], then commit as normal.

Using setDate in PreparedStatement

If you want to add the current date into the database, I would avoid calculating the date in Java to begin with. Determining "now" on the Java (client) side leads to possible inconsistencies in the database if the client side is mis-configured, has the wrong time, wrong timezone, etc. Instead, the date can be set on the server side in a manner such as the following:

requestSQL = "INSERT INTO CREDIT_REQ_TITLE_ORDER ("   +
                "REQUEST_ID, ORDER_DT, FOLLOWUP_DT) " +
                "VALUES(?, SYSDATE, SYSDATE + 30)";

...

prs.setInt(1, new Integer(requestID));

This way, only one bind parameter is required and the dates are calculated on the server side will be consistent. Even better would be to add an insert trigger to CREDIT_REQ_TITLE_ORDER and have the trigger insert the dates. That can help enforce consistency between different client apps (for example, someone trying to do a fix via sqlplus.

open failed: EACCES (Permission denied)

First give or check permissions like

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

If these two permissions are OK, then check your output streams are in correct format.

Example:

FileOutputStream fos=new FileOutputStream(Environment.getExternalStorageDirectory()+"/rahul1.jpg");

Difference between socket and websocket?

WebSocket is just another application level protocol over TCP protocol, just like HTTP.

Some snippets < Spring in Action 4> quoted below, hope it can help you understand WebSocket better.

In its simplest form, a WebSocket is just a communication channel between two applications (not necessarily a browser is involved)...WebSocket communication can be used between any kinds of applications, but the most common use of WebSocket is to facilitate communication between a server application and a browser-based application.

How do I programmatically set the value of a select box element using JavaScript?

I'm afraid I'm unable to test this at the moment, but in the past, I believe I had to give each option tag an ID, and then I did something like:

document.getElementById("optionID").select();

If that doesn't work, maybe it'll get you closer to a solution :P

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

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

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


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

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

private static void methodName(Argument args...)

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

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

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

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

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

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

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

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

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

How to make layout with View fill the remaining space?

It´s simple You set the minWidth or minHeight, depends on what you are looking for, horizontal or vertical. And for the other object(the one that you want to fill the remaining space) you set a weight of 1 (set the width to wrap it´s content), So it will fill the rest of area.

<LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:gravity="center|left"
        android:orientation="vertical" >
</LinearLayout>
<LinearLayout
        android:layout_width="80dp"
        android:layout_height="fill_parent"
        android:minWidth="80dp" >
</LinearLayout>

How to return an array from an AJAX call?

Php has a super sexy function for this, just pass the array to it:

$json = json_encode($var);

$.ajax({
url:"Example.php",
type:"POST",
dataType : "json",
success:function(msg){
    console.info(msg);
}
});

simples :)

How to remove the first character of string in PHP?

The substr() function will probably help you here:

 $str = substr($str, 1);

Strings are indexed starting from 0, and this functions second parameter takes the cutstart. So make that 1, and the first char is gone.

How to get a thread and heap dump of a Java process on Windows that's not running in a console

I recommend the Java VisualVM distributed with the JDK (jvisualvm.exe). It can connect dynamically and access the threads and heap. I have found in invaluable for some problems.

What is the best way to get the minimum or maximum value from an Array of numbers?

There isn't any reliable way to get the minimum/maximum without testing every value. You don't want to try a sort or anything like that, walking through the array is O(n), which is better than any sort algorithm can do in the general case.

ImproperlyConfigured: You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings

From The Definitive Guide to Django: Web Development Done Right:

If you’ve used Python before, you may be wondering why we’re running python manage.py shell instead of just python. Both commands will start the interactive interpreter, but the manage.py shell command has one key difference: before starting the interpreter, it tells Django which settings file to use.

Use Case: Many parts of Django, including the template system, rely on your settings, and you won’t be able to use them unless the framework knows which settings to use.

If you’re curious, here’s how it works behind the scenes. Django looks for an environment variable called DJANGO_SETTINGS_MODULE, which should be set to the import path of your settings.py. For example, DJANGO_SETTINGS_MODULE might be set to 'mysite.settings', assuming mysite is on your Python path.

When you run python manage.py shell, the command takes care of setting DJANGO_SETTINGS_MODULE for you.**

How do I replace part of a string in PHP?

Simply use str_replace:

$text = str_replace(' ', '_', $text);

You would do this after your previous substr and strtolower calls, like so:

$text = substr($text,0,10);
$text = strtolower($text);
$text = str_replace(' ', '_', $text);

If you want to get fancy, though, you can do it in one line:

$text = strtolower(str_replace(' ', '_', substr($text, 0, 10)));

how to hide <li> bullets in navigation menu and footer links BUT show them for listing items

when bullet have to hide then use:

li { list-style: none;}

when bullet have to list show, then use:

li { list-style: initial;}

Populate unique values into a VBA array from Excel

Sub GetUniqueAndCount()

    Dim d As Object, c As Range, k, tmp As String

    Set d = CreateObject("scripting.dictionary")
    For Each c In Selection
        tmp = Trim(c.Value)
        If Len(tmp) > 0 Then d(tmp) = d(tmp) + 1
    Next c

    For Each k In d.keys
        Debug.Print k, d(k)
    Next k

End Sub

How do I copy SQL Azure database to my local development server?

The accepted answer is out of date. I found a better answer: Use Import Data-tier Application

More detailed information please see this article: Restoring Azure SQL Database to a Local Server

List all files in one directory PHP

You are looking for the command scandir.

$path    = '/tmp';
$files = scandir($path);

Following code will remove . and .. from the returned array from scandir:

$files = array_diff(scandir($path), array('.', '..'));

How can I get the application's path in a .NET console application?

The answer above was 90% of what I needed, but returned a Uri instead of a regular path for me.

As explained in the MSDN forums post, How to convert URI path to normal filepath?, I used the following:

// Get normal filepath of this assembly's permanent directory
var path = new Uri(
    System.IO.Path.GetDirectoryName(
        System.Reflection.Assembly.GetExecutingAssembly().CodeBase)
    ).LocalPath;

Invalid length for a Base-64 char array

My initial guess without knowing the data would be that the UserNameToVerify is not a multiple of 4 in length. Check out the FromBase64String on msdn.

// Ok
byte[] b1 = Convert.FromBase64String("CoolDude");
// Exception
byte[] b2 = Convert.FromBase64String("MyMan");

Inverse of matrix in R

Note that if you care about speed and do not need to worry about singularities, solve() should be preferred to ginv() because it is much faster, as you can check:

require(MASS)
mat <- matrix(rnorm(1e6),nrow=1e3,ncol=1e3)

t0 <- proc.time()
inv0 <- ginv(mat)
proc.time() - t0 

t1 <- proc.time()
inv1 <- solve(mat)
proc.time() - t1 

Split a string by a delimiter in python

When you have two or more (in the example below there're three) elements in the string, then you can use comma to separate these items:

date, time, event_name = ev.get_text(separator='@').split("@")

After this line of code, the three variables will have values from three parts of the variable ev

So, if the variable ev contains this string and we apply separator '@':

Sa., 23. März@19:00@Klavier + Orchester: SPEZIAL

Then, after split operation the variable

  • date will have value "Sa., 23. März"
  • time will have value "19:00"
  • event_name will have value "Klavier + Orchester: SPEZIAL"

in querySelector: how to get the first and get the last elements? what traversal order is used in the dom?

To access the first and last elements, try.

var nodes = div.querySelectorAll('[move_id]');
var first = nodes[0];
var last = nodes[nodes.length- 1];

For robustness, add index checks.

Yes, the order of nodes is pre-order depth-first. DOM's document order is defined as,

There is an ordering, document order, defined on all the nodes in the document corresponding to the order in which the first character of the XML representation of each node occurs in the XML representation of the document after expansion of general entities. Thus, the document element node will be the first node. Element nodes occur before their children. Thus, document order orders element nodes in order of the occurrence of their start-tag in the XML (after expansion of entities). The attribute nodes of an element occur after the element and before its children. The relative order of attribute nodes is implementation-dependent.

How to make fixed header table inside scrollable div?

use StickyTableHeaders.js for this.

Header was transparent . so try to add this css .

thead {
    border-top: none;
    border-bottom: none;
    background-color: #FFF;
}

A weighted version of random.choice

As of Python v3.6, random.choices could be used to return a list of elements of specified size from the given population with optional weights.

random.choices(population, weights=None, *, cum_weights=None, k=1)

  • population : list containing unique observations. (If empty, raises IndexError)

  • weights : More precisely relative weights required to make selections.

  • cum_weights : cumulative weights required to make selections.

  • k : size(len) of the list to be outputted. (Default len()=1)


Few Caveats:

1) It makes use of weighted sampling with replacement so the drawn items would be later replaced. The values in the weights sequence in itself do not matter, but their relative ratio does.

Unlike np.random.choice which can only take on probabilities as weights and also which must ensure summation of individual probabilities upto 1 criteria, there are no such regulations here. As long as they belong to numeric types (int/float/fraction except Decimal type) , these would still perform.

>>> import random
# weights being integers
>>> random.choices(["white", "green", "red"], [12, 12, 4], k=10)
['green', 'red', 'green', 'white', 'white', 'white', 'green', 'white', 'red', 'white']
# weights being floats
>>> random.choices(["white", "green", "red"], [.12, .12, .04], k=10)
['white', 'white', 'green', 'green', 'red', 'red', 'white', 'green', 'white', 'green']
# weights being fractions
>>> random.choices(["white", "green", "red"], [12/100, 12/100, 4/100], k=10)
['green', 'green', 'white', 'red', 'green', 'red', 'white', 'green', 'green', 'green']

2) If neither weights nor cum_weights are specified, selections are made with equal probability. If a weights sequence is supplied, it must be the same length as the population sequence.

Specifying both weights and cum_weights raises a TypeError.

>>> random.choices(["white", "green", "red"], k=10)
['white', 'white', 'green', 'red', 'red', 'red', 'white', 'white', 'white', 'green']

3) cum_weights are typically a result of itertools.accumulate function which are really handy in such situations.

From the documentation linked:

Internally, the relative weights are converted to cumulative weights before making selections, so supplying the cumulative weights saves work.

So, either supplying weights=[12, 12, 4] or cum_weights=[12, 24, 28] for our contrived case produces the same outcome and the latter seems to be more faster / efficient.

LPCSTR, LPCTSTR and LPTSTR

The short answer to 2nd part of the question is simply that CString class doesn't provide a direct typecast conversion by design and what you are doing is kind of cheat.

A longer answer is the following:

The reason you can typcast CString to LPCTSTR is because CString provides this facility by overriding operator=. By design it provides conversion to only LPCTSTR pointer so the string value can't be modified with this pointer.

In other words, it simply doesn't provide an overload operator= to convert the CString into LPSTR for the same reason as above. They don't want to allow altering the string value this way.

So essentially, the trick is to use the operator CString provide and get this:

LPTSTR lptstr = (LPCTSTR) string; // CString provide this operator overload

Now LPTSTR can be further type casted to LPSTR :)

dispinfo.item.pszText = LPTSTR( lpfzfd); // accomplish the cheat :P

The correct way to get LPTSTR from 'CString' is this though (complete example):

CString str = _T("Hello");
LPTSTR lpstr = str.GetBuffer(str.GetAllocLength());
str.ReleaseBuffer(); // you must call this function if you change the string above with the pointer

Again because the GetBuffer() returns LPTSTR for that reason that now you can modify :)

How to set scope property with ng-init?

HTML:

<body ng-app="App">
    <div ng-controller="testController" >
        <input type="hidden" id="testInput" ng-model="testInput" ng-init="testInput=123" />
    </div>
    {{ testInput }}
</body>

JS:

angular.module('App', []);

testController = function ($scope) {
    console.log('test');
    $scope.$watch('testInput', testShow, true);
    function testShow() {
      console.log($scope.testInput);
    }
}

Fiddle

json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

I had similar error: "Expecting value: line 1 column 1 (char 0)"

It helped for me to add "myfile.seek(0)", move the pointer to the 0 character

with open(storage_path, 'r') as myfile:
if len(myfile.readlines()) != 0:
    myfile.seek(0)
    Bank_0 = json.load(myfile)

How to escape a JSON string to have it in a URL?

Answer given by Delan is perfect. Just adding to it - incase someone wants to name the parameters or pass multiple JSON strings separately - the below code could help!

JQuery

var valuesToPass = new Array(encodeURIComponent(VALUE_1), encodeURIComponent(VALUE_2), encodeURIComponent(VALUE_3), encodeURIComponent(VALUE_4));

data = {elements:JSON.stringify(valuesToPass)}

PHP

json_decode(urldecode($_POST('elements')));

Hope this helps!

Play a Sound with Python

pyMedia's sound example does just that. This should be all you need.

import time, wave, pymedia.audio.sound as sound
f= wave.open( 'YOUR FILE NAME', 'rb' )
sampleRate= f.getframerate()
channels= f.getnchannels()
format= sound.AFMT_S16_LE
snd= sound.Output( sampleRate, channels, format )
s= f.readframes( 300000 )
snd.play( s )

Custom designing EditText

enter image description here

For EditText in image above, You have to create two xml files in res-->drawable folder. First will be "bg_edittext_focused.xml" paste the lines of code in it

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android" >
        <solid android:color="#FFFFFF" />
        <stroke
            android:width="2dip"
            android:color="#F6F6F6" />
        <corners android:radius="2dip" />
        <padding
            android:bottom="7dip"
            android:left="7dip"
            android:right="7dip"
            android:top="7dip" />
    </shape>

Second file will be "bg_edittext_normal.xml" paste the lines of code in it

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android" >
        <solid android:color="#F6F6F6" />
        <stroke
            android:width="2dip"
            android:color="#F6F6F6" />
        <corners android:radius="2dip" />
        <padding
            android:bottom="7dip"
            android:left="7dip"
            android:right="7dip"
            android:top="7dip" />
    </shape>

In res-->drawable folder create another xml file with name "bg_edittext.xml" that will call above mentioned code. paste the following lines of code below in bg_edittext.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/bg_edittext_focused" android:state_focused="true"/>
    <item android:drawable="@drawable/bg_edittext_normal"/>
</selector>

Finally in res-->layout-->example.xml file in your case wherever you created your editText you'll call bg_edittext.xml as background

   <EditText
    :::::
    :::::  
    android:background="@drawable/bg_edittext"
    :::::
    :::::
    />

How do I shrink my SQL Server Database?

Here's another solution: Use the Database Publishing Wizard to export your schema, security and data to sql scripts. You can then take your current DB offline and re-create it with the scripts.

Sounds kind of foolish, but there are a couple advantages. First, there's no chance of losing data. Your original db (as long as you don't delete your DB when dropping it!) is safe, the new DB will be roughly as small as it can be, and you'll have two different snapshots of your current database - one ready to roll, one minified - you can choose from to back up.

Add Class to Object on Page Load

I would recommend using jQuery with this function:

$(document).ready(function(){
 $('#about').addClass('expand');
});

This will add the expand class to an element with id of about when the dom is ready on page load.

How to redirect the output of the time command to a file in Linux?

If you don't want to touch the original process' stdout and stderr, you can redirect stderr to file descriptor 3 and back:

$ { time { perl -le "print 'foo'; warn 'bar';" 2>&3; }; } 3>&2 2> time.out
foo
bar at -e line 1.
$ cat time.out

real    0m0.009s
user    0m0.004s
sys     0m0.000s

You could use that for a wrapper (e.g. for cronjobs) to monitor runtimes:

#!/bin/bash

echo "[$(date)]" "$@" >> /my/runtime.log

{ time { "$@" 2>&3; }; } 3>&2 2>> /my/runtime.log

Does document.body.innerHTML = "" clear the web page?

Whilst agreeing with Douwe Maan and Erik's answers, there are a couple of other things here that you may find useful.

Firstly, within your head tags, you can reference a separate JavaScript file, which is then reusable:

<script language="JavaScript" src="/common/common.js"></script>

where common.js is your reusable function file in a top-level directory called common.

Secondly, you can delay the operation of a script using setTimeout, e.g.:

setTimeout(someFunction, 5000);

The second argument is in milliseconds. I mention this, because you appear to be trying to delay something in your original code snippet.

Create directories using make file

All solutions including the accepted one have some issues as stated in their respective comments. The accepted answer by @jonathan-leffler is already quite good but does not take into effect that prerequisites are not necessarily to be built in order (during make -j for example). However simply moving the directories prerequisite from all to program provokes rebuilds on every run AFAICT. The following solution does not have that problem and AFAICS works as intended.

MKDIR_P := mkdir -p
OUT_DIR := build

.PHONY: directories all clean

all: $(OUT_DIR)/program

directories: $(OUT_DIR)

$(OUT_DIR):
    ${MKDIR_P} $(OUT_DIR)

$(OUT_DIR)/program: | directories
    touch $(OUT_DIR)/program

clean:
    rm -rf $(OUT_DIR)

How to add a TextView to a LinearLayout dynamically in Android?

I customized more @Suragch code. My output looks

enter image description here

I wrote a method to stop code redundancy.

public TextView createATextView(int layout_widh, int layout_height, int align,
        String text, int fontSize, int margin, int padding) {

    TextView textView_item_name = new TextView(this);

    // LayoutParams layoutParams = new LayoutParams(
    // LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    // layoutParams.gravity = Gravity.LEFT;
    RelativeLayout.LayoutParams _params = new RelativeLayout.LayoutParams(
            layout_widh, layout_height);

    _params.setMargins(margin, margin, margin, margin);
    _params.addRule(align);
    textView_item_name.setLayoutParams(_params);

    textView_item_name.setText(text);
    textView_item_name.setTextSize(TypedValue.COMPLEX_UNIT_SP, fontSize);
    textView_item_name.setTextColor(Color.parseColor("#000000"));
    // textView1.setBackgroundColor(0xff66ff66); // hex color 0xAARRGGBB
    textView_item_name.setPadding(padding, padding, padding, padding);

    return textView_item_name;

}

It can be called like

createATextView(LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT, RelativeLayout.ALIGN_PARENT_RIGHT,
            subTotal.toString(), 20, 10, 20);

Now you can add this to a RelativeLayout dynamically. LinearLayout is also same, just add a orientation.

    RelativeLayout primary_layout = new RelativeLayout(this);

    LayoutParams layoutParam = new LayoutParams(LayoutParams.MATCH_PARENT,
            LayoutParams.MATCH_PARENT);

    primary_layout.setLayoutParams(layoutParam);

    // FOR LINEAR LAYOUT SET ORIENTATION
    // primary_layout.setOrientation(LinearLayout.HORIZONTAL);

    // FOR BACKGROUND COLOR 
    primary_layout.setBackgroundColor(0xff99ccff);

    primary_layout.addView(createATextView(LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT, RelativeLayout.ALIGN_LEFT, list[i],
            20, 10, 20));
    primary_layout.addView(createATextView(LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT, RelativeLayout.ALIGN_PARENT_RIGHT,
            subTotal.toString(), 20, 10, 20));

Filtering a list of strings based on contents

Tried this out quickly in the interactive shell:

>>> l = ['a', 'ab', 'abc', 'bac']
>>> [x for x in l if 'ab' in x]
['ab', 'abc']
>>>

Why does this work? Because the in operator is defined for strings to mean: "is substring of".

Also, you might want to consider writing out the loop as opposed to using the list comprehension syntax used above:

l = ['a', 'ab', 'abc', 'bac']
result = []
for s in l:
   if 'ab' in s:
       result.append(s)

On linux SUSE or RedHat, how do I load Python 2.7

Execute the below commands to make yum work as well as python2.7

yum groupinstall -y development
yum groupinstall -y 'development tools'
yum install -y zlib-dev openssl-devel wget sqlite-devel bzip2-devel
yum -y install gcc gcc-c++ numpy python-devel scipy git boost*
yum install -y *lapack*
yum install -y gcc gcc-c++ make bison flex autoconf libtool memcached libevent libevent-devel uuidd libuuid-devel  boost boost-devel libcurl-dev libcurl curl gperf mysql-devel

cd
mkdir srk
cd srk 
wget http://www.python.org/ftp/python/2.7.6/Python-2.7.6.tar.xz
yum install xz-libs
xz -d Python-2.7.6.tar.xz
tar -xvf Python-2.7.6.tar
cd Python-2.7.6
./configure --prefix=/usr/local
make
make altinstall



echo "export PATH="/usr/local/bin:$PATH"" >> /etc/profile
source /etc/profile
mv /usr/bin/python /usr/bin/python.bak
update-alternatives --install /usr/bin/python python /usr/bin/python2.6 1
update-alternatives --install /usr/bin/python python /usr/local/bin/python2.7 2
update-alternatives --config python
sed -i "s/python/python2.6/g" /usr/bin/yum

Why can't a text column have a default value in MySQL?

I normally run sites on Linux, but I also develop on a local Windows machine. I've run into this problem many times and just fixed the tables when I encountered the problems. I installed an app yesterday to help someone out and of course ran into the problem again. So, I decided it was time to figure out what was going on - and found this thread. I really don't like the idea of changing the sql_mode of the server to an earlier mode (by default), so I came up with a simple (me thinks) solution.

This solution would of course require developers to wrap their table creation scripts to compensate for the MySQL issue running on Windows. You'll see similar concepts in dump files. One BIG caveat is that this could/will cause problems if partitioning is used.

// Store the current sql_mode
mysql_query("set @orig_mode = @@global.sql_mode");

// Set sql_mode to one that won't trigger errors...
mysql_query('set @@global.sql_mode = "MYSQL40"');

/**
 * Do table creations here...
 */

// Change it back to original sql_mode
mysql_query('set @@global.sql_mode = @orig_mode');

That's about it.

SQL Group By with an Order By

Try this query

 SELECT  data_collector_id , count (data_collector_id ) as frequency 
    from rent_flats 
    where is_contact_person_landlord = 'True' 
    GROUP BY data_collector_id 
    ORDER BY count(data_collector_id) DESC

How to get the browser language using JavaScript

Try this script to get your browser language

_x000D_
_x000D_
<script type="text/javascript">_x000D_
var userLang = navigator.language || navigator.userLanguage; _x000D_
alert ("The language is: " + userLang);_x000D_
</script>
_x000D_
_x000D_
_x000D_

Cheers

View not attached to window manager crash

For Dialog created in a Fragment, I use the following code:

ProgressDialog myDialog = new ProgressDialog(getActivity());
myDialog.setOwnerActivity(getActivity());
...
Activity activity = myDialog.getOwnerActivity();
if( activity!=null && !activity.isFinishing()) {
    myDialog.dismiss();
}

I use this pattern to deal with the case when a Fragment may be detached from the Activity.

Get JSON Data from URL Using Android?

My fairly short code to read JSON from an URL. (requires Guava due to usage of CharStreams).

    private static class VersionTask extends AsyncTask<String, String, String> {
        @Override
        protected String doInBackground(String... strings) {
            String result = null;
            URL url;
            HttpURLConnection connection = null;
            try {
                url = new URL("https://api.github.com/repos/user_name/repo_name/releases/latest");
                connection = (HttpURLConnection) url.openConnection();
                connection.connect();
                result = CharStreams.toString(new InputStreamReader(connection.getInputStream(), Charsets.UTF_8));
            } catch (IOException e) {
                Log.d("VersionTask", Log.getStackTraceString(e));
            } finally {
                if (connection != null) {
                    connection.disconnect();
                }
            }
            return result;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            if (result != null) {
                String version = "";
                try {
                    version = new JSONObject(result).optString("tag_name").trim();
                } catch (JSONException e) {
                    Log.e("VersionTask", Log.getStackTraceString(e));
                }
                if (version.startsWith("v")) {
                    //process version
                }
            }
        }
    }

PS: This code gets the latest release version (based on tag name) for a given GitHub repo.

How to link to apps on the app store

All the answers are outdated and don't work; use the below method.

All apps of a developer:
itms-apps://apps.apple.com/developer/developer-name/developerId

Single app:
itms-apps://itunes.apple.com/app/appId

Java: how to initialize String[]?

You need to initialize errorSoon, as indicated by the error message, you have only declared it.

String[] errorSoon;                   // <--declared statement
String[] errorSoon = new String[100]; // <--initialized statement

You need to initialize the array so it can allocate the correct memory storage for the String elements before you can start setting the index.

If you only declare the array (as you did) there is no memory allocated for the String elements, but only a reference handle to errorSoon, and will throw an error when you try to initialize a variable at any index.

As a side note, you could also initialize the String array inside braces, { } as so,

String[] errorSoon = {"Hello", "World"};

which is equivalent to

String[] errorSoon = new String[2];
errorSoon[0] = "Hello";
errorSoon[1] = "World";

Is it possible to change a UIButtons background color?

This can be done programmatically by making a replica:

loginButton = [UIButton buttonWithType:UIButtonTypeCustom];
[loginButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
loginButton.backgroundColor = [UIColor whiteColor];
loginButton.layer.borderColor = [UIColor blackColor].CGColor;
loginButton.layer.borderWidth = 0.5f;
loginButton.layer.cornerRadius = 10.0f;

edit: of course, you'd have to #import <QuartzCore/QuartzCore.h>

edit: to all new readers, you should also consider a few options added as "another possibility". for you consideration.

As this is an old answer, I strongly recommend reading comments for troubleshooting

Looping each row in datagridview

You could loop through DataGridView using Rows property, like:

foreach (DataGridViewRow row in datagridviews.Rows)
{
   currQty += row.Cells["qty"].Value;
   //More code here
}

How to make a button redirect to another page using jQuery or just Javascript

Use a link and style it like a button:

<a href="#page2" class="ui-btn ui-shadow ui-corner-all">Click this button</a>

Error when trying to access XAMPP from a network

This solution worked well for me: http://www.apachefriends.org/f/viewtopic.php?f=17&t=50902&p=196185#p196185

Edit /opt/lampp/etc/extra/httpd-xampp.conf and adding Require all granted line at bottom of block <Directory "/opt/lampp/phpmyadmin"> to have the following code:

<Directory "/opt/lampp/phpmyadmin">
  AllowOverride AuthConfig Limit
  Order allow,deny
  Allow from all
  Require all granted
</Directory>

FtpWebRequest Download File

I know this is an old Post but I am adding here for future reference. Here is a solution that I found:

    private void DownloadFileFTP()
    {
        string inputfilepath = @"C:\Temp\FileName.exe";
        string ftphost = "xxx.xx.x.xxx";
        string ftpfilepath = "/Updater/Dir1/FileName.exe";

        string ftpfullpath = "ftp://" + ftphost + ftpfilepath;

        using (WebClient request = new WebClient())
        {
            request.Credentials = new NetworkCredential("UserName", "P@55w0rd");
            byte[] fileData = request.DownloadData(ftpfullpath);

            using (FileStream file = File.Create(inputfilepath))
            {
                file.Write(fileData, 0, fileData.Length);
                file.Close();
            }
            MessageBox.Show("Download Complete");
        }
    }

Updated based upon excellent suggestion by Ilya Kogan

JAXB: How to ignore namespace during unmarshalling XML document?

I have encoding problems with XMLFilter solution, so I made XMLStreamReader to ignore namespaces:

class XMLReaderWithoutNamespace extends StreamReaderDelegate {
    public XMLReaderWithoutNamespace(XMLStreamReader reader) {
      super(reader);
    }
    @Override
    public String getAttributeNamespace(int arg0) {
      return "";
    }
    @Override
    public String getNamespaceURI() {
      return "";
    }
}

InputStream is = new FileInputStream(name);
XMLStreamReader xsr = XMLInputFactory.newFactory().createXMLStreamReader(is);
XMLReaderWithoutNamespace xr = new XMLReaderWithoutNamespace(xsr);
Unmarshaller um = jc.createUnmarshaller();
Object res = um.unmarshal(xr);

Changing width property of a :before css selector using JQuery

I don't think there's a jQuery-way to directly access the pseudoclass' rules, but you could always append a new style element to the document's head like:

$('head').append('<style>.column:before{width:800px !important;}</style>');

See a live demo here

I also remember having seen a plugin that tackles this issue once but I couldn't find it on first googling unfortunately.

iPhone X / 8 / 8 Plus CSS media queries

It seems that the most accurate (and seamless) method of adding the padding for iPhone X/8 using env()...

padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);

Here's a link describing this:

https://css-tricks.com/the-notch-and-css/

CSS selectors ul li a {...} vs ul > li > a {...}

">" is the child selector

"" is the descendant selector

The difference is that a descendant can be a child of the element, or a child of a child of the element or a child of a child of a child ad inifinitum.

A child element is simply one that is directly contained within the parent element:

<foo> <!-- parent -->
  <bar> <!-- child of foo, descendant of foo -->
    <baz> <!-- descendant of foo -->
    </baz>
  </bar>
</foo>

for this example, foo * would match <bar> and <baz>, whereas foo > * would only match <bar>.

As for your second question:

Which one is more efficient and why?

I'm not actually going to answer this question as it's completely irrelevant to development. CSS rendering engines are so fast that there is almost never* a reason to optimize CSS selectors beyond making them as short as possible.

Instead of worrying about micro-optimizations, focus on writing selectors that make sense for the case at hand. I often use > selectors when styling nested lists, because it's important to distinguish which level of the list is being styled.

* if it genuinely is an issue in rendering the page, you've probably got too many elements on the page, or too much CSS. Then you'll have to run some tests to see what the actual issue is.

How do I get console input in javascript?

Good old readline();.

See MDN (archive).

IPC performance: Named Pipe vs Socket

I'm going to agree with shodanex, it looks like you're prematurely trying to optimize something that isn't yet problematic. Unless you know sockets are going to be a bottleneck, I'd just use them.

A lot of people who swear by named pipes find a little savings (depending on how well everything else is written), but end up with code that spends more time blocking for an IPC reply than it does doing useful work. Sure, non-blocking schemes help this, but those can be tricky. Spending years bringing old code into the modern age, I can say, the speedup is almost nil in the majority of cases I've seen.

If you really think that sockets are going to slow you down, then go out of the gate using shared memory with careful attention to how you use locks. Again, in all actuality, you might find a small speedup, but notice that you're wasting a portion of it waiting on mutual exclusion locks. I'm not going to advocate a trip to futex hell (well, not quite hell anymore in 2015, depending upon your experience).

Pound for pound, sockets are (almost) always the best way to go for user space IPC under a monolithic kernel .. and (usually) the easiest to debug and maintain.

PHP Fatal error: Class 'PDO' not found

I solved it with library PHP_PDO , because my hosting provider didn't accept my requirement for installation of PDO driver to apache server.

What is the difference between atomic / volatile / synchronized?

I know that two threads can not enter in Synchronize block at the same time

Two thread cannot enter a synchronized block on the same object twice. This means that two threads can enter the same block on different objects. This confusion can lead to code like this.

private Integer i = 0;

synchronized(i) {
   i++;
}

This will not behave as expected as it could be locking on a different object each time.

if this is true than How this atomic.incrementAndGet() works without Synchronize ?? and is thread safe ??

yes. It doesn't use locking to achieve thread safety.

If you want to know how they work in more detail, you can read the code for them.

And what is difference between internal reading and writing to Volatile Variable / Atomic Variable ??

Atomic class uses volatile fields. There is no difference in the field. The difference is the operations performed. The Atomic classes use CompareAndSwap or CAS operations.

i read in some article that thread has local copy of variables what is that ??

I can only assume that it referring to the fact that each CPU has its own cached view of memory which can be different from every other CPU. To ensure that your CPU has a consistent view of data, you need to use thread safety techniques.

This is only an issue when memory is shared at least one thread updates it.

Killing a process using Java

If you start the process from with in your Java application (ex. by calling Runtime.exec() or ProcessBuilder.start()) then you have a valid Process reference to it, and you can invoke the destroy() method in Process class to kill that particular process.

But be aware that if the process that you invoke creates new sub-processes, those may not be terminated (see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4770092).

On the other hand, if you want to kill external processes (which you did not spawn from your Java app), then one thing you can do is to call O/S utilities which allow you to do that. For example, you can try a Runtime.exec() on kill command under Unix / Linux and check for return values to ensure that the application was killed or not (0 means success, -1 means error). But that of course will make your application platform dependent.

How to filter input type="file" dialog by specific file type?

This will give the correct (custom) filter when the file dialog is showing:

<input type="file" accept=".jpg, .png, .jpeg, .gif, .bmp, .tif, .tiff|image/*">

CSS: image link, change on hover

If you have just a few places where you wish to create this effect, you can use the following html code that requires no css. Just insert it.

<a href="TARGET URL GOES HERE"><img src="URL OF FIRST IMAGE GOES HERE" 
onmouseover="this.src='URL OF IMAGE ON HOVER GOES HERE'"
onmouseout="this.src='URL OF FIRST IMAGE GOES HERE AGAIN'" /></A>

Be sure to write the quote marks exactly as they are here, or it will not work.

How to convert a string to ASCII

I think this code may be help you:

string str = char.ConvertFromUtf32(65)

How to send a pdf file directly to the printer using JavaScript?

<?php

$browser_ver = get_browser(null,true);
//echo $browser_ver['browser'];

if($browser_ver['browser'] == 'IE') {
?>

<!DOCTYPE html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>pdf print test</title>
<style>
    html { height:100%; }
</style>
<script>
    function printIt(id) {
        var pdf = document.getElementById("samplePDF");
        pdf.click();
        pdf.setActive();
        pdf.focus();
        pdf.print();
    }
</script>
</head>

<body style="margin:0; height:100%;">

<embed id="samplePDF" type="application/pdf" src="/pdfs/2010/dash_fdm350.pdf" width="100%" height="100%" />
<button onClick="printIt('samplePDF')">Print</button>


</body>
</html>

<?php
} else {
?>
<HTML>
<script Language="javascript">

function printfile(id) { 
    window.frames[id].focus();
    window.frames[id].print();
} 

</script>
<BODY marginheight="0" marginwidth="0">

<iframe src="/pdfs/2010/dash_fdm350.pdf" id="objAdobePrint" name="objAdobePrint" height="95%" width="100%" frameborder=0></iframe><br>

<input type="button" value="Print" onclick="javascript:printfile('objAdobePrint');">

</BODY>
</HTML>
<?php
}
?>

Converting String array to java.util.List

On Java 14 you can do this

List<String> strings = Arrays.asList("one", "two", "three");

Creating folders inside a GitHub repository without using Git

After searching a lot I find out that it is possible to create a new folder from the web interface, but it would require you to have at least one file within the folder when creating it.

When using the normal way of creating new files through the web interface, you can type in the folder into the file name to create the file within that new directory.

For example, if I would like to create the file filename.md in a series of sub-folders, I can do this (taken from the GitHub blog):

Enter image description here

C# Dictionary get item by index

Your key is a string and your value is an int. Your code won't work because it cannot look up the random int you pass. Also, please provide full code

Why declare unicode by string in python?

That doesn't set the format of the string; it sets the format of the file. Even with that header, "hello" is a byte string, not a Unicode string. To make it Unicode, you're going to have to use u"hello" everywhere. The header is just a hint of what format to use when reading the .py file.

Kill all processes for a given user

What about iterating on the /proc virtual file system ? http://linux.die.net/man/5/proc ?

One line if in VB .NET

Just add Then:

If A = 1 Then A = 2

or:

If A = 1 Then _
    A = 2

Change header background color of modal of twitter bootstrap

All the other answersoverflow:hidden?alert-danger not work for me in Bootstrap 4, but I found a simple solution in Bootstrap 4. Since the white trim comes from modal-content, just add border-0 class to it and the white trim disappear.

Example: https://codepen.io/eric1214/pen/BajLwzE?editors=1010

Refer to a cell in another worksheet by referencing the current worksheet's name?

Unless you want to go the VBA route to work out the Tab name, the Excel formula is fairly ugly based upon Mid functions, etc. But both these methods can be found here if you want to go that way.

Rather, the way I would do it is:

1) Make one cell on your sheet named, for example, Reference_Sheet and put in that cell the value "Jan Item" for example.

2) Now, use the Indirect function like:

=INDIRECT(Reference_Sheet&"!J3") 

3) Now, for each month's sheet, you just have to change that one Reference_Sheet cell.

Hope this gives you what you're looking for!

How to Execute SQL Server Stored Procedure in SQL Developer?

    EXECUTE [or EXEC] procedure_name
  @parameter_1_Name = 'parameter_1_Value', 
    @parameter_2_name = 'parameter_2_value',
    @parameter_z_name = 'parameter_z_value'

How to start automatic download of a file in Internet Explorer?

A simple bit of jQuery solved this problem for me.

$(function() {
   $(window).bind('load', function() {
      $("div.downloadProject").delay(1500).append('<iframe width="0" height="0" frameborder="0" src="[YOUR FILE SRC]"></iframe>'); 
   });
});

In my HTML, I simply have

<div class="downloadProject"></div>

All this does is wait a second and a half, then append the div with the iframe referring to the file that you want to download. When the iframe is updated onto the page, your browser downloads the file. Simple as that. :D

How do I enable NuGet Package Restore in Visual Studio?

This approach worked for me:

  • Close VS2015
  • Open the solution temporarily in VS2013 and enable nuget package restore by right clicking on the solution (i also did a rebuild, but I suspect that is not needed).
  • Close VS2013
  • Reopen the solution in VS2015

You have now enabled nuget package restore in VS2015 as well.

SQL Insert into table only if record doesn't exist

Although the answer I originally marked as chosen is correct and achieves what I asked there is a better way of doing this (which others acknowledged but didn't go into). A composite unique index should be created on the table consisting of fund_id and date.

ALTER TABLE funds ADD UNIQUE KEY `fund_date` (`fund_id`, `date`);

Then when inserting a record add the condition when a conflict is encountered:

INSERT INTO funds (`fund_id`, `date`, `price`)
    VALUES (23, DATE('2013-02-12'), 22.5)
        ON DUPLICATE KEY UPDATE `price` = `price`; --this keeps the price what it was (no change to the table) or:

INSERT INTO funds (`fund_id`, `date`, `price`)
    VALUES (23, DATE('2013-02-12'), 22.5)
        ON DUPLICATE KEY UPDATE `price` = 22.5; --this updates the price to the new value

This will provide much better performance to a sub-query and the structure of the table is superior. It comes with the caveat that you can't have NULL values in your unique key columns as they are still treated as values by MySQL.

css 100% width div not taking up full width of parent

html, body{ 
  width:100%;
}

This tells the html to be 100% wide. But 100% refers to the whole browser window width, so no more than that.

You may want to set a min width instead.

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

So it will be 100% as a minimum, bot more if needed.

How to send a HTTP OPTIONS request from the command line?

The curl installed by default in Debian supports HTTPS since a great while back. (a long time ago there were two separate packages, one with and one without SSL but that's not the case anymore)

OPTIONS /path

You can send an OPTIONS request with curl like this:

curl -i -X OPTIONS http://example.org/path

You may also use -v instead of -i to see more output.

OPTIONS *

To send a plain * (instead of the path, see RFC 7231) with the OPTIONS method, you need curl 7.55.0 or later as then you can run a command line like:

curl -i --request-target "*" -X OPTIONS http://example.org

C# error: "An object reference is required for the non-static field, method, or property"

It looks like you want:

public static string GetRandomBits()

Without static, you would need an object before you can call the GetRandomBits() method. However, since the implementation of GetRandomBits() does not depend on the state of any Program object, it's best to declare it static.

Determine the number of lines within a text file

You could quickly read it in, and increment a counter, just use a loop to increment, doing nothing with the text.

Sort Java Collection

As of Java 8 you now can do it with a stream using a lambda:

list.stream().sorted(Comparator.comparing(customObject::getId))
             .foreach(object -> System.out.println(object));

How to merge a Series and DataFrame

Update
From v0.24.0 onwards, you can merge on DataFrame and Series as long as the Series is named.

df.merge(s.rename('new'), left_index=True, right_index=True)
# If series is already named,
# df.merge(s, left_index=True, right_index=True)

Nowadays, you can simply convert the Series to a DataFrame with to_frame(). So (if joining on index):

df.merge(s.to_frame(), left_index=True, right_index=True)

.mp4 file not playing in chrome

I too had the same issue. I changed the codec to H264-MPEG-4 AVC and the videos started working in HTML5/Chrome.

Option selected in converter: H264-MPEG-4 AVC, Codec visible in VLC player: H264-MPEG-4 AVC (part 10) (avc1)

Hope it helps...

How do you convert CString and std::string std::wstring to each other?

One interesting approach is to cast CString to CStringA inside a string constructor. Unlike std::string s((LPCTSTR)cs); this will work even if _UNICODE is defined. However, if that is the case, this will perform conversion from Unicode to ANSI, so it is unsafe for higher Unicode values beyond the ASCII character set. Such conversion is subject to the _CSTRING_DISABLE_NARROW_WIDE_CONVERSION preprocessor definition. https://msdn.microsoft.com/en-us/library/5bzxfsea.aspx

        CString s1("SomeString");
        string s2((CStringA)s1);

How to temporarily disable a click handler in jQuery?

This is a more idiomatic alternative to the artificial state variable solutions:

$("#button_id").one('click', DoSomething);

function DoSomething() {
  // do something.

  $("#button_id").one('click', DoSomething);
}

One will only execute once (until attached again). More info here: http://docs.jquery.com/Events/one

Using Math.round to round to one decimal place?

Double toBeTruncated = new Double("2.25");

Double truncatedDouble = new BigDecimal(toBeTruncated).setScale(1, BigDecimal.ROUND_HALF_UP).doubleValue();

it will return 2.3

SQL GROUP BY CASE statement with aggregate function

While Shannon's answer is technically correct, it looks like overkill.

The simple solution is that you need to put your summation outside of the case statement. This should do the trick:

sum(CASE WHEN col1 > col2 THEN col3*col4 ELSE 0 END) AS some_product

Basically, your old code tells SQL to execute the sum(X*Y) for each line individually (leaving each line with its own answer that can't be grouped).

The code line I have written takes the sum product, which is what you want.

nodeJS - How to create and read session with express

It is cumbersome to interoperate socket.io and connect sessions support. The problem is not because socket.io "hijacks" request somehow, but because certain socket.io transports (I think flashsockets) don't support cookies. I could be wrong with cookies, but my approach is the following:

  1. Implement a separate session store for socket.io that stores data in the same format as connect-redis
  2. Make connect session cookie not http-only so it's accessible from client JS
  3. Upon a socket.io connection, send session cookie over socket.io from browser to server
  4. Store the session id in a socket.io connection, and use it to access session data from redis.

Free space in a CMD shell

I make a variation to generate this out from script:

volume C: - 49 GB total space / 29512314880 byte(s) free

I use diskpart to get this information.

@echo off
setlocal enableextensions enabledelayedexpansion
set chkfile=drivechk.tmp
if "%1" == "" goto :usage
set drive=%1
set drive=%drive:\=%
set drive=%drive::=%
dir %drive%:>nul 2>%chkfile%
for %%? in (%chkfile%) do (
  set chksize=%%~z?
)
if %chksize% neq 0 (
  more %chkfile%
  del %chkfile%
  goto :eof
)
del %chkfile%
echo list volume | diskpart | find /I " %drive% " >%chkfile%
for /f "tokens=6" %%a in ('type %chkfile%' ) do (
    set dsksz=%%a
)
for /f "tokens=7" %%a in ('type %chkfile%' ) do (
    set dskunit=%%a
)
del %chkfile%
for /f "tokens=3" %%a in ('dir %drive%:\') do (
  set bytesfree=%%a
)
set bytesfree=%bytesfree:,=%
echo volume %drive%: - %dsksz% %dskunit% total space / %bytesfree% byte(s) free
endlocal

goto :eof
:usage
  echo.
  echo   usage: freedisk ^<driveletter^> (eg.: freedisk c)

Count the number of items in my array list

Outside of your loop create an int:

int numberOfItemIds = 0;
for (int i = 0; i < key.length; i++) {

Then in the loop, increment it:

itemId = p.getItemId();
numberOfItemIds++;

UTF-8 encoded html pages show ? (questions marks) instead of characters

Looks like nobody mentioned

SET NAMES utf8;

I found this solution here and it helped me. How to apply it:

To be all UTF-8, issue the following statement just after you’ve made the connection to the database server: SET NAMES utf8;

Maybe this will help someone.

printf, wprintf, %s, %S, %ls, char* and wchar*: Errors not announced by a compiler warning?

For s: When used with printf functions, specifies a single-byte or multi-byte character string; when used with wprintf functions, specifies a wide-character string. Characters are displayed up to the first null character or until the precision value is reached.

For S: When used with printf functions, specifies a wide-character string; when used with wprintf functions, specifies a single-byte or multi-byte character string. Characters are displayed up to the first null character or until the precision value is reached.

In Unix-like platform, s and S have the same meaning as windows platform.

Reference: https://msdn.microsoft.com/en-us/library/hf4y5e3w.aspx

SQLite equivalent to ISNULL(), NVL(), IFNULL() or COALESCE()

You can easily define such function and use it then:

ifnull <- function(x,y) {
  if(is.na(x)==TRUE) 
    return (y)
  else 
    return (x);
}

or same minified version:

ifnull <- function(x,y) {if(is.na(x)==TRUE) return (y) else return (x);}

Reactjs setState() with a dynamic key name?

Thanks to @Cory's hint, i used this:

inputChangeHandler : function (event) {
    var stateObject = function() {
      returnObj = {};
      returnObj[this.target.id] = this.target.value;
         return returnObj;
    }.bind(event)();

    this.setState( stateObject );    
},

If using ES6 or the Babel transpiler to transform your JSX code, you can accomplish this with computed property names, too:

inputChangeHandler : function (event) {
    this.setState({ [event.target.id]: event.target.value });
    // alternatively using template strings for strings
    // this.setState({ [`key${event.target.id}`]: event.target.value });
}

Right click to select a row in a Datagridview and show a menu to delete it

private void dgvOferty_CellContextMenuStripNeeded(object sender, DataGridViewCellContextMenuStripNeededEventArgs e)
    {
        dgvOferty.ClearSelection();
        int rowSelected = e.RowIndex;
        if (e.RowIndex != -1)
        {
            this.dgvOferty.Rows[rowSelected].Selected = true;
        }
        e.ContextMenuStrip = cmstrip;
    }

TADA :D. The easiest way period. For custom cells just modify a little.

In C/C++ what's the simplest way to reverse the order of bits in a byte?

If you are talking about a single byte, a table-lookup is probably the best bet, unless for some reason you don't have 256 bytes available.

nodejs mysql Error: Connection lost The server closed the connection

I do not recall my original use case for this mechanism. Nowadays, I cannot think of any valid use case.

Your client should be able to detect when the connection is lost and allow you to re-create the connection. If it important that part of program logic is executed using the same connection, then use transactions.

tl;dr; Do not use this method.


A pragmatic solution is to force MySQL to keep the connection alive:

setInterval(function () {
    db.query('SELECT 1');
}, 5000);

I prefer this solution to connection pool and handling disconnect because it does not require to structure your code in a way thats aware of connection presence. Making a query every 5 seconds ensures that the connection will remain alive and PROTOCOL_CONNECTION_LOST does not occur.

Furthermore, this method ensures that you are keeping the same connection alive, as opposed to re-connecting. This is important. Consider what would happen if your script relied on LAST_INSERT_ID() and mysql connection have been reset without you being aware about it?

However, this only ensures that connection time out (wait_timeout and interactive_timeout) does not occur. It will fail, as expected, in all others scenarios. Therefore, make sure to handle other errors.

Is there a format code shortcut for Visual Studio?

Select all text in the document and press Ctrl + E + D.

Why does an SSH remote command get fewer environment variables then when run manually?

Shell environment does not load when running remote ssh command. You can edit ssh environment file:

vi ~/.ssh/environment

Its format is:

VAR1=VALUE1
VAR2=VALUE2

Also, check sshd configuration for PermitUserEnvironment=yes option.

Convert seconds to hh:mm:ss in Python

Besides the fact that Python has built in support for dates and times (see bigmattyh's response), finding minutes or hours from seconds is easy:

minutes = seconds / 60
hours = minutes / 60

Now, when you want to display minutes or seconds, MOD them by 60 so that they will not be larger than 59