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Some Of The Best Answers From Latest Asked Questions

IOS: verify if a point is inside a rect

UIView's pointInside:withEvent: could be a good solution. Will return a boolean value indicating wether or not the given CGPoint is in the UIView instance you are using. Example:

UIView *aView = [UIView alloc]initWithFrame:CGRectMake(0,0,100,100);
CGPoint aPoint = CGPointMake(5,5);
BOOL isPointInsideView = [aView pointInside:aPoint withEvent:nil];

What's the fastest way to read a text file line-by-line?

To find the fastest way to read a file line by line you will have to do some benchmarking. I have done some small tests on my computer but you cannot expect that my results apply to your environment.

Using StreamReader.ReadLine

This is basically your method. For some reason you set the buffer size to the smallest possible value (128). Increasing this will in general increase performance. The default size is 1,024 and other good choices are 512 (the sector size in Windows) or 4,096 (the cluster size in NTFS). You will have to run a benchmark to determine an optimal buffer size. A bigger buffer is - if not faster - at least not slower than a smaller buffer.

const Int32 BufferSize = 128;
using (var fileStream = File.OpenRead(fileName))
  using (var streamReader = new StreamReader(fileStream, Encoding.UTF8, true, BufferSize)) {
    String line;
    while ((line = streamReader.ReadLine()) != null)
      // Process line
  }

The FileStream constructor allows you to specify FileOptions. For example, if you are reading a large file sequentially from beginning to end, you may benefit from FileOptions.SequentialScan. Again, benchmarking is the best thing you can do.

Using File.ReadLines

This is very much like your own solution except that it is implemented using a StreamReader with a fixed buffer size of 1,024. On my computer this results in slightly better performance compared to your code with the buffer size of 128. However, you can get the same performance increase by using a larger buffer size. This method is implemented using an iterator block and does not consume memory for all lines.

var lines = File.ReadLines(fileName);
foreach (var line in lines)
  // Process line

Using File.ReadAllLines

This is very much like the previous method except that this method grows a list of strings used to create the returned array of lines so the memory requirements are higher. However, it returns String[] and not an IEnumerable<String> allowing you to randomly access the lines.

var lines = File.ReadAllLines(fileName);
for (var i = 0; i < lines.Length; i += 1) {
  var line = lines[i];
  // Process line
}

Using String.Split

This method is considerably slower, at least on big files (tested on a 511 KB file), probably due to how String.Split is implemented. It also allocates an array for all the lines increasing the memory required compared to your solution.

using (var streamReader = File.OpenText(fileName)) {
  var lines = streamReader.ReadToEnd().Split("\r\n".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
  foreach (var line in lines)
    // Process line
}

My suggestion is to use File.ReadLines because it is clean and efficient. If you require special sharing options (for example you use FileShare.ReadWrite), you can use your own code but you should increase the buffer size.

How to set cursor position in EditText?

Let editText2 is your second EditText view .then put following piece of code in onResume()

editText2.setFocusableInTouchMode(true);
editText2.requestFocus();

or put

<requestFocus />

in your xml layout of the second EditText view.

Tar archiving that takes input from a list of files

Some versions of tar, for example, the default versions on HP-UX (I tested 11.11 and 11.31), do not include a command line option to specify a file list, so a decent work-around is to do this:

tar cvf allfiles.tar $(cat mylist.txt)

Select NOT IN multiple columns

I'm not sure whether you think about:

select * from friend f
where not exists (
    select 1 from likes l where f.id1 = l.id and f.id2 = l.id2
)

it works only if id1 is related with id1 and id2 with id2 not both.

Convert an integer to an array of digits

I can't add comments to Vladimir's solution, but I think that this is more efficient also when your initial numbers could be also below 10.

This is my proposal:

int temp = test;
ArrayList<Integer> array = new ArrayList<Integer>();
do{
  array.add(temp % 10);
  temp /= 10;
} while  (temp > 1);

Remember to reverse the array.

To draw an Underline below the TextView in Android

You can use Kotlin Extension and type your own drawUnderLine method.

fun TextView.drawUnderLine() {
    val text = SpannableString(this.text.toString())
    text.setSpan(UnderlineSpan(), 0, text.length, 0)
    this.text = text
}
yourTextView.drawUnderLine()

jQuery Ajax PUT with parameters

You can use the PUT method and pass data that will be included in the body of the request:

let data = {"key":"value"}

$.ajax({
    type: 'PUT',
    url: 'http://example.com/api',
    contentType: 'application/json',
    data: JSON.stringify(data), // access in body
}).done(function () {
    console.log('SUCCESS');
}).fail(function (msg) {
    console.log('FAIL');
}).always(function (msg) {
    console.log('ALWAYS');
});

How to obtain image size using standard Python class (without using external library)?

While it's possible to call open(filename, 'rb') and check through the binary image headers for the dimensions, it seems much more useful to install PIL and spend your time writing great new software! You gain greater file format support and the reliability that comes from widespread usage. From the PIL documentation, it appears that the code you would need to complete your task would be:

from PIL import Image
im = Image.open('filename.png')
print 'width: %d - height: %d' % im.size # returns (width, height) tuple

As for writing code yourself, I'm not aware of a module in the Python standard library that will do what you want. You'll have to open() the image in binary mode and start decoding it yourself. You can read about the formats at:

How to assign string to bytes array

Besides the methods mentioned above, you can also do a trick as

s := "hello"
b := *(*[]byte)(unsafe.Pointer((*reflect.SliceHeader)(unsafe.Pointer(&s))))

Go Play: http://play.golang.org/p/xASsiSpQmC

You should never use this :-)

No Such Element Exception?

Looks like your file.next() line in the while loop is throwing the NoSuchElementException since the scanner reached the end of file. Read the next() java API here

Also you should not call next() in the loop and also in the while condition. In the while condition you should check if next token is available and inside the while loop check if its equal to treasure.

How to convert char* to wchar_t*?

const char* text_char = "example of mbstowcs";
size_t length = strlen(text_char );

Example of usage "mbstowcs"

std::wstring text_wchar(length, L'#');

//#pragma warning (disable : 4996)
// Or add to the preprocessor: _CRT_SECURE_NO_WARNINGS
mbstowcs(&text_wchar[0], text_char , length);

Example of usage "mbstowcs_s"

Microsoft suggest to use "mbstowcs_s" instead of "mbstowcs".

Links:

Mbstowcs example

mbstowcs_s, _mbstowcs_s_l

wchar_t text_wchar[30];

mbstowcs_s(&length, text_wchar, text_char, length);

Pinging an IP address using PHP and echoing the result

I have developed the algorithm to work with heterogeneous OS, both Windows and Linux.

Implement the following class:

<?php

    class CheckDevice {

        public function myOS(){
            if (strtoupper(substr(PHP_OS, 0, 3)) === (chr(87).chr(73).chr(78)))
                return true;

            return false;
        }

        public function ping($ip_addr){
            if ($this->myOS()){
                if (!exec("ping -n 1 -w 1 ".$ip_addr." 2>NUL > NUL && (echo 0) || (echo 1)"))
                    return true;
            } else {
                if (!exec("ping -q -c1 ".$ip_addr." >/dev/null 2>&1 ; echo $?"))
                    return true;
            }

            return false;
        }
    }

    $ip_addr = "151.101.193.69"; #DNS: www.stackoverflow.com

    if ((new CheckDevice())->ping($ip_addr))
        echo "The device exists";
    else 
        echo "The device is not connected";

How to implement custom JsonConverter in JSON.NET to deserialize a List of base class objects?

Just thought i would share a solution also based on this that works with the Knowntype attribute using reflection , had to get derived class from any base class, solution can benefit from recursion to find the best matching class though i didn't need it in my case, matching is done by the type given to the converter if it has KnownTypes it will scan them all until it matches a type that has all the properties inside the json string, first one to match will be chosen.

usage is as simple as:

 string json = "{ Name:\"Something\", LastName:\"Otherthing\" }";
 var ret  = JsonConvert.DeserializeObject<A>(json, new KnownTypeConverter());

in the above case ret will be of type B.

JSON classes:

[KnownType(typeof(B))]
public class A
{
   public string Name { get; set; }
}

public class B : A
{
   public string LastName { get; set; }
}

Converter code:

/// <summary>
    /// Use KnownType Attribute to match a divierd class based on the class given to the serilaizer
    /// Selected class will be the first class to match all properties in the json object.
    /// </summary>
    public  class KnownTypeConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return System.Attribute.GetCustomAttributes(objectType).Any(v => v is KnownTypeAttribute);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            // Load JObject from stream
            JObject jObject = JObject.Load(reader);

            // Create target object based on JObject
            System.Attribute[] attrs = System.Attribute.GetCustomAttributes(objectType);  // Reflection. 

                // Displaying output. 
            foreach (System.Attribute attr in attrs)
            {
                if (attr is KnownTypeAttribute)
                {
                    KnownTypeAttribute k = (KnownTypeAttribute) attr;
                    var props = k.Type.GetProperties();
                    bool found = true;
                    foreach (var f in jObject)
                    {
                        if (!props.Any(z => z.Name == f.Key))
                        {
                            found = false;
                            break;
                        }
                    }

                    if (found)
                    {
                        var target = Activator.CreateInstance(k.Type);
                        serializer.Populate(jObject.CreateReader(),target);
                        return target;
                    }
                }
            }
            throw new ObjectNotFoundException();


            // Populate the object properties

        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }
    }

New to MongoDB Can not run command mongo

I think your log output states it clearly;

exception in initAndListen: 10296 dbpath (/data/db) does not exist, terminating

You may simply create this directory or better to define it as a configuration value within your configuration file then use it as mongod -f C:\path\to\your\mongodb.conf.

How to fix "Headers already sent" error in PHP

This error message gets triggered when anything is sent before you send HTTP headers (with setcookie or header). Common reasons for outputting something before the HTTP headers are:

  • Accidental whitespace, often at the beginning or end of files, like this:

     <?php
    // Note the space before "<?php"
    ?>
    

       To avoid this, simply leave out the closing ?> - it's not required anyways.

  • Byte order marks at the beginning of a php file. Examine your php files with a hex editor to find out whether that's the case. They should start with the bytes 3F 3C. You can safely remove the BOM EF BB BF from the start of files.
  • Explicit output, such as calls to echo, printf, readfile, passthru, code before <? etc.
  • A warning outputted by php, if the display_errors php.ini property is set. Instead of crashing on a programmer mistake, php silently fixes the error and emits a warning. While you can modify the display_errors or error_reporting configurations, you should rather fix the problem.
    Common reasons are accesses to undefined elements of an array (such as $_POST['input'] without using empty or isset to test whether the input is set), or using an undefined constant instead of a string literal (as in $_POST[input], note the missing quotes).

Turning on output buffering should make the problem go away; all output after the call to ob_start is buffered in memory until you release the buffer, e.g. with ob_end_flush.

However, while output buffering avoids the issues, you should really determine why your application outputs an HTTP body before the HTTP header. That'd be like taking a phone call and discussing your day and the weather before telling the caller that he's got the wrong number.

How to list all AWS S3 objects in a bucket using Java

As a slightly more concise solution to listing S3 objects when they might be truncated:

ListObjectsRequest request = new ListObjectsRequest().withBucketName(bucketName);
ObjectListing listing = null;

while((listing == null) || (request.getMarker() != null)) {
  listing = s3Client.listObjects(request);
  // do stuff with listing
  request.setMarker(listing.getNextMarker());
}

CodeIgniter: "Unable to load the requested class"

If you're using a linux server for your application then it is necessary to use lowercase file name and class name to avoid this issue.

Ex.

Filename: csvsample.php

class csvsample {

}

Correct way to quit a Qt program?

If you're using Qt Jambi, this should work:

QApplication.closeAllWindows();

How do I center this form in css?

Try adding this to your css

.form { width:985px; margin:0 auto }

and add width:100% to the body tag

Then put:

<div class="form">

before the tag.

How to read from input until newline is found using scanf()?

use getchar and a while that look like this

while(x = getchar())
{   
    if(x == '\n'||x == '\0')
       do what you need when space or return is detected
    else
        mystring.append(x)
}

Sorry if I wrote a pseudo-code but I don't work with C language from a while.

How do I capture the output into a variable from an external process in PowerShell?

Another real-life example:

$result = & "$env:cust_tls_store\Tools\WDK\x64\devcon.exe" enable $strHwid 2>&1 | Out-String

Notice that this example includes a path (which begins with an environment variable). Notice that the quotes must surround the path and the EXE file, but not the parameters!

Note: Don't forget the & character in front of the command, but outside of the quotes.

The error output is also collected.

It took me a while to get this combination working, so I thought that I would share it.

MySQL: determine which database is selected?

Just use mysql_query (or mysqli_query, even better, or use PDO, best of all) with:

SELECT DATABASE() FROM DUAL;

Addendum:

There is much discussion over whether or not FROM DUAL should be included in this or not. On a technical level, it is a holdover from Oracle and can safely be removed. If you are inclined, you can use the following instead:

SELECT DATABASE();

That said, it is perhaps important to note, that while FROM DUAL does not actually do anything, it is valid MySQL syntax. From a strict perspective, including braces in a single line conditional in JavaScript also does not do anything, but it is still a valid practice.

How do I negate a condition in PowerShell?

If you are like me and dislike the double parenthesis, you can use a function

function not ($cm, $pm) {
  if (& $cm $pm) {0} else {1}
}

if (not Test-Path C:\Code) {'it does not exist!'}

Example

Uninstall all installed gems, in OSX?

If you are using Rubygems version 2.1.0 or later, you can try: gem uninstall --all.

Windows batch script to unhide files hidden by virus

Try this one. Hope this is working fine.. :)

@ECHO off

cls

ECHO.

set drvltr=

set /p drvltr=Enter Drive letter: 

attrib -s -h -a /s /d  %drvltr%:\*.*

ECHO Unhide Completed

pause

Where to find Application Loader app in Mac?

You can also upload an app using the Application Loader tool by using it from the terminal:

MacBook-Pro:~ denis$ altool --upload-app -f "ios-app.ipa" -u "[email protected]" -p "yourpassword"

To use altool from anywhere in the terminal you could add it to your PATH env variable by typing in terminal:

MacBook-Pro:~ denis$ export PATH=$PATH:/Applications/Xcode.app/Contents/Applications/Application\ Loader.app/Contents/Frameworks/ITunesSoftwareService.framework/Support/
MacBook-Pro:~ denis$ source ~/.bash_profile

Know relationships between all the tables of database in SQL Server

My solution is based on @marc_s solution, i just concatenated columns in cases that a constraint is based on more than one column:

SELECT
   FK.[name] AS ForeignKeyConstraintName
  ,SCHEMA_NAME(FT.schema_id) + '.' + FT.[name] AS ForeignTable
  ,STUFF(ForeignColumns.ForeignColumns, 1, 2, '') AS ForeignColumns
  ,SCHEMA_NAME(RT.schema_id) + '.' + RT.[name] AS ReferencedTable
  ,STUFF(ReferencedColumns.ReferencedColumns, 1, 2, '') AS ReferencedColumns
FROM
  sys.foreign_keys FK
  INNER JOIN sys.tables FT
  ON FT.object_id = FK.parent_object_id
  INNER JOIN sys.tables RT
  ON RT.object_id = FK.referenced_object_id
  CROSS APPLY
  (
    SELECT
      ', ' + iFC.[name] AS [text()]
    FROM
      sys.foreign_key_columns iFKC
      INNER JOIN sys.columns iFC
      ON iFC.object_id = iFKC.parent_object_id
        AND iFC.column_id = iFKC.parent_column_id
    WHERE
      iFKC.constraint_object_id = FK.object_id
    ORDER BY
      iFC.[name]
    FOR XML PATH('')
  ) ForeignColumns (ForeignColumns)
  CROSS APPLY
  (
    SELECT
      ', ' + iRC.[name]AS [text()]
    FROM
      sys.foreign_key_columns iFKC
      INNER JOIN sys.columns iRC
      ON iRC.object_id = iFKC.referenced_object_id
        AND iRC.column_id = iFKC.referenced_column_id
    WHERE
      iFKC.constraint_object_id = FK.object_id
    ORDER BY
      iRC.[name]
    FOR XML PATH('')
  ) ReferencedColumns (ReferencedColumns)

Using C++ base class constructors?

Here is a good discussion about superclass constructor calling rules. You always want the base class constructor to be called before the derived class constructor in order to form an object properly. Which is why this form is used

  B( int v) : A( v )
  {
  }

Phonegap + jQuery Mobile, real world sample or tutorial

These may not solve exactly your "real-world problems", but perhaps something useful ...

Our web site includes PhoneGap and jQuery Mobile tutorials for a media player, barcode scanner, google maps, and OAuth.

Also, my github page has code, but no tutorial, for two apps:

  • AppLaudApp - a run-control, debugging enabling, download complementary app to a cloud IDE
  • NameTrendz - an app developed in at Android Dev Camp to do a bunch of queries about popular name data. The PhoneGap and jQuery Mobile versions are from March 2011.

Create PostgreSQL ROLE (user) if it doesn't exist

The same solution as for Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL? should work - send a CREATE USER … to \gexec.

Workaround from within psql

SELECT 'CREATE USER my_user'
WHERE NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = 'my_user')\gexec

Workaround from the shell

echo "SELECT 'CREATE USER my_user' WHERE NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = 'my_user')\gexec" | psql

See accepted answer there for more details.

Simultaneously merge multiple data.frames in a list

You can do it using merge_all in the reshape package. You can pass parameters to merge using the ... argument

reshape::merge_all(list_of_dataframes, ...)

Here is an excellent resource on different methods to merge data frames.

delete all record from table in mysql

It’s because you tried to update a table without a WHERE that uses a KEY column.

The quick fix is to add SET SQL_SAFE_UPDATES=0; before your query :

SET SQL_SAFE_UPDATES=0; 

Or

close the safe update mode. Edit -> Preferences -> SQL Editor -> SQL Editor remove Forbid UPDATE and DELETE statements without a WHERE clause (safe updates) .

BTW you can use TRUNCATE TABLE tablename; to delete all the records .

How to parse json string in Android?

Below is the link which guide in parsing JSON string in android.

http://www.ibm.com/developerworks/xml/library/x-andbene1/?S_TACT=105AGY82&S_CMP=MAVE

Also according to your json string code snippet must be something like this:-

JSONObject mainObject = new JSONObject(yourstring);

JSONObject universityObject = mainObject.getJSONObject("university");
JSONString name = universityObject.getString("name");  
JSONString url = universityObject.getString("url");

Following is the API reference for JSOnObject: https://developer.android.com/reference/org/json/JSONObject.html#getString(java.lang.String)

Same for other object.

How to display activity indicator in middle of the iphone screen?

Code updated for Swift 3

enter image description here

Swift code

import UIKit
class ViewController: UIViewController {

    let activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.whiteLarge)

    @IBOutlet weak var myBlueSubview: UIView!

    @IBAction func showButtonTapped(sender: UIButton) {
        activityIndicator.startAnimating()
    }

    @IBAction func hideButtonTapped(sender: UIButton) {
        activityIndicator.stopAnimating()
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // set up activity indicator
        activityIndicator.center = CGPoint(x: myBlueSubview.bounds.size.width/2, y: myBlueSubview.bounds.size.height/2)
        activityIndicator.color = UIColor.yellow
        myBlueSubview.addSubview(activityIndicator)
    }
}

Notes

  • You can center the activity indicator in middle of the screen by adding it as a subview to the root view rather than myBlueSubview.

    activityIndicator.center =  CGPoint(x: self.view.bounds.size.width/2, y: self.view.bounds.size.height/2)
    self.view.addSubview(activityIndicator)
    
  • You can also create the UIActivityIndicatorView in the Interface Builder. Just drag an Activity Indicator View onto the storyboard and set the properties. Be sure to check Hides When Stopped. Use an outlet to call startAnimating() and stopAnimating(). See this tutorial.

enter image description here

  • Remember that the default color of the LargeWhite style is white. So if you have a white background you can't see it, just change the color to black or whatever other color you want.

    activityIndicator.color = UIColor.black
    
  • A common use case would be while a background task runs. Here is an example:

    // start animating before the background task starts
    activityIndicator.startAnimating()
    
    // background task
    DispatchQueue.global(qos: .userInitiated).async {
    
        doSomethingThatTakesALongTime()
    
        // return to the main thread
        DispatchQueue.main.async {
    
            // stop animating now that background task is finished
            self.activityIndicator.stopAnimating()
        }
    }
    

SQL Server - Convert varchar to another collation (code page) to fix character encoding

Must be used convert, not cast:

SELECT
 CONVERT(varchar(50), N'æøåáälcçcédnoöruýtžš')
 COLLATE Cyrillic_General_CI_AI

(http://blog.sqlpositive.com/2010/03/using-convert-with-collate-to-strip-accents-from-unicode-strings/)

Show a leading zero if a number is less than 10

There's no built-in JavaScript function to do this, but you can write your own fairly easily:

function pad(n) {
    return (n < 10) ? ("0" + n) : n;
}

EDIT:

Meanwhile there is a native JS function that does that. See String#padStart

_x000D_
_x000D_
console.log(String(5).padStart(2, '0'));
_x000D_
_x000D_
_x000D_

How do I add multiple "NOT LIKE '%?%' in the WHERE clause of sqlite3?

this is a select command

   FROM
    user
WHERE
    application_key = 'dsfdsfdjsfdsf'
        AND email NOT LIKE '%applozic.com'
        AND email NOT LIKE '%gmail.com'
        AND email NOT LIKE '%kommunicate.io';

this update command

 UPDATE user
    SET email = null
    WHERE application_key='dsfdsfdjsfdsf' and  email not like '%applozic.com' 
    and email not like '%gmail.com'  and email not like '%kommunicate.io';

Installing a local module using npm?

Missing the main property?

As previous people have answered npm --save ../location-of-your-packages-root-directory. The ../location-of-your-packages-root-directory however must have two things in order for it to work.

1) package.json in that directory pointed towards

2) main property in the package.json must be set and working i.g. "main": "src/index.js", if the entry file for ../location-of-your-packages-root-directory is ../location-of-your-packages-root-directory/src/index.js

How to customise file type to syntax associations in Sublime Text?

I put my customized changes in the User package:

*nix: ~/.config/sublime-text-2/Packages/User/Scala.tmLanguage
*Windows: %APPDATA%\Sublime Text 2\Packages\User\Scala.tmLanguage

Which also means it's in JSON format:

{
  "extensions":
  [
    "sbt"
  ]
}

This is the same place the

View -> Syntax -> Open all with current extension as ...

menu item adds it (creating the file if it doesn't exist).

How do I URL encode a string

New APIs have been added since the answer was selected; You can now use NSURLUtilities. Since different parts of URLs allow different characters, use the applicable character set. The following example encodes for inclusion in the query string:

encodedString = [myString stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLQueryAllowedCharacterSet];

To specifically convert '&', you'll need to remove it from the url query set or use a different set, as '&' is allowed in a URL query:

NSMutableCharacterSet *chars = NSCharacterSet.URLQueryAllowedCharacterSet.mutableCopy;
[chars removeCharactersInRange:NSMakeRange('&', 1)]; // %26
encodedString = [myString stringByAddingPercentEncodingWithAllowedCharacters:chars];

How do I convert a single character into it's hex ascii value in python

To use the hex encoding in Python 3, use

>>> import codecs
>>> codecs.encode(b"c", "hex")
b'63'

In legacy Python, there are several other ways of doing this:

>>> hex(ord("c"))
'0x63'
>>> format(ord("c"), "x")
'63'
>>> "c".encode("hex")
'63'

Using Mockito with multiple calls to the same method with the same arguments

You can even chain doReturn() method invocations like this

doReturn(null).doReturn(anotherInstance).when(mock).method();

cute isn't it :)

Installing Python 3 on RHEL

Here are the steps i followed to install Python3:

yum install wget
wget https://www.python.org/ftp/python/3.6.0/Python-3.6.0.tar.xz  
sudo tar xvf Python-3.*   
cd Python-3.* 
sudo ./configure --prefix=/opt/python3    
sudo make   
sudo make install   
sudo ln -s /opt/python3/bin/python3 /usr/bin/python3

$ /usr/bin/python3    
Python 3.6.0

Objective-C and Swift URL encoding

This can work in Objective C ARC.Use CFBridgingRelease to cast a Core Foundation-style object as an Objective-C object and transfer ownership of the object to ARC .See Function CFBridgingRelease here.

+ (NSString *)encodeUrlString:(NSString *)string {
return CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes
                         (kCFAllocatorDefault,
                          (__bridge CFStringRef)string,
                          NULL,
                          CFSTR("!*'();:@&=+$,/?%#[]"),
                          kCFStringEncodingUTF8)
                         );}

How to make phpstorm display line numbers by default?

Just now found where is it on Windows. Its View -> Active Editor -> Show Line Numbers (changes only for current document) and File -> Settings -> Editor -> Appearance -> Show Line Numbers (for all documents)

For Mac Version go to PhpStorm -> Preferences in menu. In the preference window go to IDE settings -> Editor -> Appearance -> Show Line Numbers (To change setting for all documents)

OR if you want to quickly set show line number PER CURRENT WINDOW even easier - right click on the long white column (where breakpoints are set) then select Show Line Numbers.

enter image description here

Red dot on the screenshot is a place where you have to click

Iterate through Nested JavaScript Objects

You can create a recursive function like this to do a depth-first traversal of the cars object.

var findObjectByLabel = function(obj, label) {
    if(obj.label === label) { return obj; }
    for(var i in obj) {
        if(obj.hasOwnProperty(i)){
            var foundLabel = findObjectByLabel(obj[i], label);
            if(foundLabel) { return foundLabel; }
        }
    }
    return null;
};

which can be called like so

findObjectByLabel(car, "Chevrolet");

Getting value from JQUERY datepicker

To position the datepicker next to the input field you could use following code.

$('#datepicker').datepicker({
    beforeShow: function(input, inst)
    {
        inst.dpDiv.css({marginLeft: input.offsetWidth + 'px'});
    }
});

No suitable driver found for 'jdbc:mysql://localhost:3306/mysql

When using Netbean, go under project tab and click the dropdown button there to select Libraries folder. Right Click on d Library folder and select 'Add JAR/Folder'. Locate the mysql-connectore-java.*.jar file where u have it on ur system. This worked for me and I hope it does for u too. Revert if u encounter any problem

Jquery: Find Text and replace

Joanna Avalos answer is better, Just note that I replaced .text() to .html(), otherwise, some of the html elements inside that will be destroyed.

Returning a regex match in VBA (excel)

You need to access the matches in order to get at the SDI number. Here is a function that will do it (assuming there is only 1 SDI number per cell).

For the regex, I used "sdi followed by a space and one or more numbers". You had "sdi followed by a space and zero or more numbers". You can simply change the + to * in my pattern to go back to what you had.

Function ExtractSDI(ByVal text As String) As String

Dim result As String
Dim allMatches As Object
Dim RE As Object
Set RE = CreateObject("vbscript.regexp")

RE.pattern = "(sdi \d+)"
RE.Global = True
RE.IgnoreCase = True
Set allMatches = RE.Execute(text)

If allMatches.count <> 0 Then
    result = allMatches.Item(0).submatches.Item(0)
End If

ExtractSDI = result

End Function

If a cell may have more than one SDI number you want to extract, here is my RegexExtract function. You can pass in a third paramter to seperate each match (like comma-seperate them), and you manually enter the pattern in the actual function call:

Ex) =RegexExtract(A1, "(sdi \d+)", ", ")

Here is:

Function RegexExtract(ByVal text As String, _
                      ByVal extract_what As String, _
                      Optional seperator As String = "") As String

Dim i As Long, j As Long
Dim result As String
Dim allMatches As Object
Dim RE As Object
Set RE = CreateObject("vbscript.regexp")

RE.pattern = extract_what
RE.Global = True
Set allMatches = RE.Execute(text)

For i = 0 To allMatches.count - 1
    For j = 0 To allMatches.Item(i).submatches.count - 1
        result = result & seperator & allMatches.Item(i).submatches.Item(j)
    Next
Next

If Len(result) <> 0 Then
    result = Right(result, Len(result) - Len(seperator))
End If

RegexExtract = result

End Function

*Please note that I have taken "RE.IgnoreCase = True" out of my RegexExtract, but you could add it back in, or even add it as an optional 4th parameter if you like.

SQL string value spanning multiple lines in query

SQL Server allows the following (be careful to use single quotes instead of double)

UPDATE User
SET UserId = 12345
   , Name = 'J Doe'
   , Location = 'USA'
   , Bio='my bio
spans 
multiple
lines!'
WHERE UserId = 12345

How to get "their" changes in the middle of conflicting Git rebase?

If you want to pull a particular file from another branch just do

git checkout branch1 -- filenamefoo.txt

This will pull a version of the file from one branch into the current tree

Can constructors be async?

I'm not familiar with the async keyword (is this specific to Silverlight or a new feature in the beta version of Visual Studio?), but I think I can give you an idea of why you can't do this.

If I do:

var o = new MyObject();
MessageBox(o.SomeProperty.ToString());

o may not be done initializing before the next line of code runs. An instantiation of your object cannot be assigned until your constructor is completed, and making the constructor asynchronous wouldn't change that so what would be the point? However, you could call an asynchronous method from your constructor and then your constructor could complete and you would get your instantiation while the async method is still doing whatever it needs to do to setup your object.

StringStream in C#

You have a number of options:

One is to not use streams, but use the TextWriter

   void Print(TextWriter writer) 
   {
   }

   void Main() 
  {
    var textWriter = new StringWriter();
    Print(writer);
    string myString = textWriter.ToString();
   }

It's likely that TextWriter is the appropriate level of abstraction for your print function. Streams are aimed at writing binary data, while TextWriter works at a higher abstraction level, specifically geared towards outputting strings.

If your motivation is that you also want your Print function to write to files, you can get a text writer from a filestream as well.

void Print(TextWriter writer) 
{
}

void PrintToFile(string filePath) 
{
     using(var textWriter = new StreamWriter(filePath))
     {
         Print(writer);
     }
}

If you REALLY want a stream you can look at MemoryStream.

How to compare two dates?

Use time

Let's say you have the initial dates as strings like these:
date1 = "31/12/2015"
date2 = "01/01/2016"

You can do the following:
newdate1 = time.strptime(date1, "%d/%m/%Y") and newdate2 = time.strptime(date2, "%d/%m/%Y") to convert them to python's date format. Then, the comparison is obvious:

newdate1 > newdate2 will return False
newdate1 < newdate2 will return True

How to select a value in dropdown javascript?

Using Javascript:

document.getElementById('drpSelectSourceLibrary').value = 'Seven';

Using Jquery:

$('select').prop('selectedIndex', 3); // This will select the 4th option from the dropdown list

Does svn have a `revert-all` command?

You could do:

svn revert -R .

This will not delete any new file not under version control. But you can easily write a shell script to do that like:

for file in `svn status|grep "^ *?"|sed -e 's/^ *? *//'`; do rm $file ; done

javax.persistence.NoResultException: No entity found for query

Another option is to use uniqueResultOptional() method, which gives you Optional in result:

String hql="from DrawUnusedBalance where unusedBalanceDate= :today";
Query query=em.createQuery(hql);
query.setParameter("today",new LocalDate());

Optional<DrawUnusedBalance> drawUnusedBalance=query.uniqueResultOptional();

Masking password input from the console : Java

A full example ?. Run this code : (NB: This example is best run in the console and not from within an IDE, since the System.console() method might return null in that case.)

import java.io.Console;
public class Main {

    public void passwordExample() {        
        Console console = System.console();
        if (console == null) {
            System.out.println("Couldn't get Console instance");
            System.exit(0);
        }

        console.printf("Testing password%n");
        char[] passwordArray = console.readPassword("Enter your secret password: ");
        console.printf("Password entered was: %s%n", new String(passwordArray));

    }

    public static void main(String[] args) {
        new Main().passwordExample();
    }
}

Should I use @EJB or @Inject

@Inject can inject any bean, while @EJB can only inject EJBs. You can use either to inject EJBs, but I'd prefer @Inject everywhere.

Query Mongodb on month, day, year... of a datetime

You can use MongoDB_DataObject wrapper to perform such query like below:

$model = new MongoDB_DataObject('orders');

$model->whereAdd('MONTH(created) = 4 AND YEAR(created) = 2016');

$model->find();

while ($model->fetch()) {
    var_dump($model);
}

OR, similarly, using direct query string:

$model = new MongoDB_DataObject();

$model->query('SELECT * FROM orders WHERE MONTH(created) = 4 AND YEAR(created) = 2016');

while ($model->fetch()) {
    var_dump($model);
}

How to merge rows in a column into one cell in excel?

For those who have Excel 2016 (and I suppose next versions), there is now directly the CONCAT function, which will replace the CONCATENATE function.

So the correct way to do it in Excel 2016 is :

=CONCAT(A1:A4)

which will produce :

Iamaboy

For users of olders versions of Excel, the other answers are relevant.

How to encode URL parameters?

With PHP

echo urlencode("http://www.image.com/?username=unknown&password=unknown");

Result

http%3A%2F%2Fwww.image.com%2F%3Fusername%3Dunknown%26password%3Dunknown

With Javascript:

var myUrl = "http://www.image.com/?username=unknown&password=unknown";
var encodedURL= "http://www.foobar.com/foo?imageurl=" + encodeURIComponent(myUrl);

DEMO: http://jsfiddle.net/Lpv53/

psycopg2: insert multiple rows with one query

I built a program that inserts multiple lines to a server that was located in another city.

I found out that using this method was about 10 times faster than executemany. In my case tup is a tuple containing about 2000 rows. It took about 10 seconds when using this method:

args_str = ','.join(cur.mogrify("(%s,%s,%s,%s,%s,%s,%s,%s,%s)", x) for x in tup)
cur.execute("INSERT INTO table VALUES " + args_str) 

and 2 minutes when using this method:

cur.executemany("INSERT INTO table VALUES(%s,%s,%s,%s,%s,%s,%s,%s,%s)", tup)

How can I set a custom date time format in Oracle SQL Developer?

SQL Developer Version 4.1.0.19

Step 1: Go to Tools -> Preferences

Step 2: Select Database -> NLS

Step 3: Go to Date Format and Enter DD-MON-RR HH24: MI: SS

Step 4: Click OK.

Get latest from Git branch

If you have forked a repository fro Delete your forked copy and fork it again from master.

Android: upgrading DB version and adding new table

You can use SQLiteOpenHelper's onUpgrade method. In the onUpgrade method, you get the oldVersion as one of the parameters.

In the onUpgrade use a switch and in each of the cases use the version number to keep track of the current version of database.

It's best that you loop over from oldVersion to newVersion, incrementing version by 1 at a time and then upgrade the database step by step. This is very helpful when someone with database version 1 upgrades the app after a long time, to a version using database version 7 and the app starts crashing because of certain incompatible changes.

Then the updates in the database will be done step-wise, covering all possible cases, i.e. incorporating the changes in the database done for each new version and thereby preventing your application from crashing.

For example:

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    switch (oldVersion) {
    case 1:
        String sql = "ALTER TABLE " + TABLE_SECRET + " ADD COLUMN " + "name_of_column_to_be_added" + " INTEGER";
        db.execSQL(sql);
        break;

    case 2:
        String sql = "SOME_QUERY";
        db.execSQL(sql);
        break;
    }

}

error: unknown type name ‘bool’

Somewhere in your code there is a line #include <string>. This by itself tells you that the program is written in C++. So using g++ is better than gcc.

For the missing library: you should look around in the file system if you can find a file called libl.so. Use the locate command, try /usr/lib, /usr/local/lib, /opt/flex/lib, or use the brute-force find / | grep /libl.

Once you have found the file, you have to add the directory to the compiler command line, for example:

g++ -o scan lex.yy.c -L/opt/flex/lib -ll

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

The ISO C99 standard specifies that these macros must only be defined if explicitly requested.

#define __STDC_FORMAT_MACROS
#include <inttypes.h>

... now PRIu64 will work

What is the difference between __dirname and ./ in node.js?

The gist

In Node.js, __dirname is always the directory in which the currently executing script resides (see this). So if you typed __dirname into /d1/d2/myscript.js, the value would be /d1/d2.

By contrast, . gives you the directory from which you ran the node command in your terminal window (i.e. your working directory) when you use libraries like path and fs. Technically, it starts out as your working directory but can be changed using process.chdir().

The exception is when you use . with require(). The path inside require is always relative to the file containing the call to require.

For example...

Let's say your directory structure is

/dir1
  /dir2
    pathtest.js

and pathtest.js contains

var path = require("path");
console.log(". = %s", path.resolve("."));
console.log("__dirname = %s", path.resolve(__dirname));

and you do

cd /dir1/dir2
node pathtest.js

you get

. = /dir1/dir2
__dirname = /dir1/dir2

Your working directory is /dir1/dir2 so that's what . resolves to. Since pathtest.js is located in /dir1/dir2 that's what __dirname resolves to as well.

However, if you run the script from /dir1

cd /dir1
node dir2/pathtest.js

you get

. = /dir1
__dirname = /dir1/dir2

In that case, your working directory was /dir1 so that's what . resolved to, but __dirname still resolves to /dir1/dir2.

Using . inside require...

If inside dir2/pathtest.js you have a require call into include a file inside dir1 you would always do

require('../thefile')

because the path inside require is always relative to the file in which you are calling it. It has nothing to do with your working directory.

How to redirect to the same page in PHP

Another elegant one is

header("Location: http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]");
exit;

JQuery: dynamic height() with window resize()

To see the window height while (or after) it is resized, try it:

$(window).resize(function() {
$('body').prepend('<div>' + $(window).height() - 46 + '</div>');
});

How can query string parameters be forwarded through a proxy_pass with nginx?

you have to use rewrite to pass params using proxy_pass here is example I did for angularjs app deployment to s3

S3 Static Website Hosting Route All Paths to Index.html

adopted to your needs would be something like

location /service/ {
    rewrite ^\/service\/(.*) /$1 break;
    proxy_pass http://apache;
}

if you want to end up in http://127.0.0.1:8080/query/params/

if you want to end up in http://127.0.0.1:8080/service/query/params/ you'll need something like

location /service/ {
    rewrite ^\/(.*) /$1 break;
    proxy_pass http://apache;
}

using extern template (C++11)

If you have used extern for functions before, exactly same philosophy is followed for templates. if not, going though extern for simple functions may help. Also, you may want to put the extern(s) in header file and include the header when you need it.

Load a Bootstrap popover content with AJAX. Is this possible?

Display ajax popover on static element with hover trigger:

$('.hover-ajax').popover({
    "html": true,
    trigger: 'hover',
    "content": function(){
        var div_id =  "tmp-id-" + $.now();
        return details_in_popup($(this).attr('href'), div_id);
    }
});

function details_in_popup(link, div_id){
    $.ajax({
        url: link,
        success: function(response){
            $('#'+div_id).html(response);
        }
    });
    return '<div id="'+ div_id +'">Loading...</div>';
}

Html :

<span class="hover-ajax" href="http://domain.tld/file.php"> Hey , hoover me ! </span>

How do I point Crystal Reports at a new database

Choose Database | Set Datasource Location... Select the database node (yellow-ish cylinder) of the current connection, then select the database node of the desired connection (you may need to authenticate), then click Update.

You will need to do this for the 'Subreports' nodes as well.

FYI, you can also do individual tables by selecting each individually, then choosing Update.

Reading value from console, interactively

you can't do a "while(done)" loop because that would require blocking on input, something node.js doesn't like to do.

Instead set up a callback to be called each time something is entered:

var stdin = process.openStdin();

stdin.addListener("data", function(d) {
    // note:  d is an object, and when converted to a string it will
    // end with a linefeed.  so we (rather crudely) account for that  
    // with toString() and then trim() 
    console.log("you entered: [" + 
        d.toString().trim() + "]");
  });

DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss") is returning AM time instead of PM time?

Use HH for 24 hour hours format:

DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")

Or the tt format specifier for the AM/PM part:

DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss tt")

Take a look at the custom Date and Time format strings documentation.

Parsing a YAML file in Python, and accessing the data?

Since PyYAML's yaml.load() function parses YAML documents to native Python data structures, you can just access items by key or index. Using the example from the question you linked:

import yaml
with open('tree.yaml', 'r') as f:
    doc = yaml.load(f)

To access branch1 text you would use:

txt = doc["treeroot"]["branch1"]
print txt
"branch1 text"

because, in your YAML document, the value of the branch1 key is under the treeroot key.

Redirect after Login on WordPress

// Used theme's functions.php  
add_action('login_form', 'redirect_after_login'); 
function redirect_after_login() 
{     
global $redirect_to; 
if   (!isset($_GET['redirect_to'])) 
{ 
$redirect_to =   get_option('sample-page');
//  sample-page = your page name after site_url
} }

Passing a method parameter using Task.Factory.StartNew

class Program
{
    static void Main(string[] args)
    {
        Task.Factory.StartNew(() => MyMethod("param value"));
    }

    private static void MyMethod(string p)
    {
        Console.WriteLine(p);
    }
}

Hibernate Criteria Restrictions AND / OR combination

For the new Criteria since version Hibernate 5.2:

CriteriaBuilder criteriaBuilder = getSession().getCriteriaBuilder();
CriteriaQuery<SomeClass> criteriaQuery = criteriaBuilder.createQuery(SomeClass.class);

Root<SomeClass> root = criteriaQuery.from(SomeClass.class);

Path<Object> expressionA = root.get("A");
Path<Object> expressionB = root.get("B");

Predicate predicateAEqualX = criteriaBuilder.equal(expressionA, "X");
Predicate predicateBInXY = expressionB.in("X",Y);
Predicate predicateLeft = criteriaBuilder.and(predicateAEqualX, predicateBInXY);

Predicate predicateAEqualY = criteriaBuilder.equal(expressionA, Y);
Predicate predicateBEqualZ = criteriaBuilder.equal(expressionB, "Z");
Predicate predicateRight = criteriaBuilder.and(predicateAEqualY, predicateBEqualZ);

Predicate predicateResult = criteriaBuilder.or(predicateLeft, predicateRight);

criteriaQuery
        .select(root)
        .where(predicateResult);

List<SomeClass> list = getSession()
        .createQuery(criteriaQuery)
        .getResultList();  

How to convert a const char * to std::string

std::string str(c_str, strnlen(c_str, max_length));

At Christian Rau's request:

strnlen is specified in POSIX.1-2008 and available in GNU's glibc and the Microsoft run-time library. It is not yet found in some other systems; you may fall back to Gnulib's substitute.

How do I reset the setInterval timer?

Once you clear the interval using clearInterval you could setInterval once again. And to avoid repeating the callback externalize it as a separate function:

var ticker = function() {
    console.log('idle');
};

then:

var myTimer = window.setInterval(ticker, 4000);

then when you decide to restart:

window.clearInterval(myTimer);
myTimer = window.setInterval(ticker, 4000);

Javascript how to split newline

Since you are using textarea, you may find \n or \r (or \r\n) for line breaks. So, the following is suggested:

$('#keywords').val().split(/\r|\n/)

ref: check whether string contains a line break

How can I send and receive WebSocket messages on the server side?

In addition to the PHP frame encoding function, here follows a decode function:

function Decode($M){
    $M = array_map("ord", str_split($M));
    $L = $M[1] AND 127;

    if ($L == 126)
        $iFM = 4;
    else if ($L == 127)
        $iFM = 10;
    else
        $iFM = 2;

    $Masks = array_slice($M, $iFM, 4);

    $Out = "";
    for ($i = $iFM + 4, $j = 0; $i < count($M); $i++, $j++ ) {
        $Out .= chr($M[$i] ^ $Masks[$j % 4]);
    }
    return $Out;
}

I've implemented this and also other functions in an easy-to-use WebSocket PHP class here.

The representation of if-elseif-else in EL using JSF

You can use "ELSE IF" using conditional operator in expression language as below:

 <p:outputLabel value="#{transaction.status.equals('PNDNG')?'Pending':
                                     transaction.status.equals('RJCTD')?'Rejected':
                                     transaction.status.equals('CNFRMD')?'Confirmed':
                                     transaction.status.equals('PSTD')?'Posted':''}"/>

How does one use the onerror attribute of an img element

This is actually tricky, especially if you plan on returning an image url for use cases where you need to concatenate strings with the onerror condition image URL, e.g. you might want to programatically set the url parameter in CSS.

The trick is that image loading is asynchronous by nature so the onerror doesn't happen sunchronously, i.e. if you call returnPhotoURL it immediately returns undefined bcs the asynchronous method of loading/handling the image load just began.

So, you really need to wrap your script in a Promise then call it like below. NOTE: my sample script does some other things but shows the general concept:

returnPhotoURL().then(function(value){
    doc.getElementById("account-section-image").style.backgroundImage = "url('" + value + "')";
}); 


function returnPhotoURL(){
    return new Promise(function(resolve, reject){
        var img = new Image();
        //if the user does not have a photoURL let's try and get one from gravatar
        if (!firebase.auth().currentUser.photoURL) {
            //first we have to see if user han an email
            if(firebase.auth().currentUser.email){
                //set sign-in-button background image to gravatar url
                img.addEventListener('load', function() {
                    resolve (getGravatar(firebase.auth().currentUser.email, 48));
                }, false);
                img.addEventListener('error', function() {
                    resolve ('//rack.pub/media/fallbackImage.png');
                }, false);            
                img.src = getGravatar(firebase.auth().currentUser.email, 48);
            } else {
                resolve ('//rack.pub/media/fallbackImage.png');
            }
        } else {
            img.addEventListener('load', function() {
                resolve (firebase.auth().currentUser.photoURL);
            }, false);
            img.addEventListener('error', function() {
                resolve ('https://rack.pub/media/fallbackImage.png');
            }, false);      
            img.src = firebase.auth().currentUser.photoURL;
        }
    });
}

How I can delete in VIM all text from current line to end of file?

:.,$d

This will delete all content from current line to end of the file. This is very useful when you're dealing with test vector generation or stripping.

Passing on command line arguments to runnable JAR

You can pass program arguments on the command line and get them in your Java app like this:

public static void main(String[] args) {
  String pathToXml = args[0];
....
}

Alternatively you pass a system property by changing the command line to:

java -Dpath-to-xml=enwiki-20111007-pages-articles.xml -jar wiki2txt

and your main class to:

public static void main(String[] args) {
  String pathToXml = System.getProperty("path-to-xml");
....
}

Python: How to check a string for substrings from a list?

Try this test:

any(substring in string for substring in substring_list)

It will return True if any of the substrings in substring_list is contained in string.

Note that there is a Python analogue of Marc Gravell's answer in the linked question:

from itertools import imap
any(imap(string.__contains__, substring_list)) 

In Python 3, you can use map directly instead:

any(map(string.__contains__, substring_list))

Probably the above version using a generator expression is more clear though.

Getting pids from ps -ef |grep keyword

ps -ef | grep KEYWORD | grep -v grep | awk '{print $2}'

How to use parameters with HttpPost

Generally speaking an HTTP POST assumes the content of the body contains a series of key/value pairs that are created (most usually) by a form on the HTML side. You don't set the values using setHeader, as that won't place them in the content body.

So with your second test, the problem that you have here is that your client is not creating multiple key/value pairs, it only created one and that got mapped by default to the first argument in your method.

There are a couple of options you can use. First, you could change your method to accept only one input parameter, and then pass in a JSON string as you do in your second test. Once inside the method, you then parse the JSON string into an object that would allow access to the fields.

Another option is to define a class that represents the fields of the input types and make that the only input parameter. For example

class MyInput
{
    String str1;
    String str2;

    public MyInput() { }
      //  getters, setters
 }

@POST
@Consumes({"application/json"})
@Path("create/")
public void create(MyInput in){
System.out.println("value 1 = " + in.getStr1());
System.out.println("value 2 = " + in.getStr2());
}

Depending on the REST framework you are using it should handle the de-serialization of the JSON for you.

The last option is to construct a POST body that looks like:

str1=value1&str2=value2

then add some additional annotations to your server method:

public void create(@QueryParam("str1") String str1, 
                  @QueryParam("str2") String str2)

@QueryParam doesn't care if the field is in a form post or in the URL (like a GET query).

If you want to continue using individual arguments on the input then the key is generate the client request to provide named query parameters, either in the URL (for a GET) or in the body of the POST.

TypeError: 'float' object not iterable

for i in count: means for i in 7:, which won't work. The bit after the in should be of an iterable type, not a number. Try this:

for i in range(count):

String "true" and "false" to boolean

Security Notice

Note that this answer in its bare form is only appropriate for the other use case listed below rather than the one in the question. While mostly fixed, there have been numerous YAML related security vulnerabilities which were caused by loading user input as YAML.


A trick I use for converting strings to bools is YAML.load, e.g.:

YAML.load(var) # -> true/false if it's one of the below

YAML bool accepts quite a lot of truthy/falsy strings:

y|Y|yes|Yes|YES|n|N|no|No|NO
|true|True|TRUE|false|False|FALSE
|on|On|ON|off|Off|OFF

Another use case

Assume that you have a piece of config code like this:

config.etc.something = ENV['ETC_SOMETHING']

And in command line:

$ export ETC_SOMETHING=false

Now since ENV vars are strings once inside code, config.etc.something's value would be the string "false" and it would incorrectly evaluate to true. But if you do like this:

config.etc.something = YAML.load(ENV['ETC_SOMETHING'])

it would be all okay. This is compatible with loading configs from .yml files as well.

How to convert SQL Server's timestamp column to datetime format

I will assume that you've done a data dump as insert statements, and you (or whoever Googles this) are attempting to figure out the date and time, or translate it for use elsewhere (eg: to convert to MySQL inserts). This is actually easy in any programming language.

Let's work with this:

CAST(0x0000A61300B1F1EB AS DateTime)

This Hex representation is actually two separate data elements... Date and Time. The first four bytes are date, the second four bytes are time.

  • The date is 0x0000A613
  • The time is 0x00B1F1EB

Convert both of the segments to integers using the programming language of your choice (it's a direct hex to integer conversion, which is supported in every modern programming language, so, I will not waste space with code that may or may not be the programming language you're working in).

  • The date of 0x0000A613 becomes 42515
  • The time of 0x00B1F1EB becomes 11661803

Now, what to do with those integers:

Date

Date is since 01/01/1900, and is represented as days. So, add 42,515 days to 01/01/1900, and your result is 05/27/2016.

Time

Time is a little more complex. Take that INT and do the following to get your time in microseconds since midnight (pseudocode):

TimeINT=Hex2Int(HexTime)
MicrosecondsTime = TimeINT*10000/3

From there, use your language's favorite function calls to translate microseconds (38872676666.7 µs in the example above) into time.

The result would be 10:47:52.677

Sorting HashMap by values

found a solution but not sure the performance if the map has large size, useful for normal case.

   /**
     * sort HashMap<String, CustomData> by value
     * CustomData needs to provide compareTo() for comparing CustomData
     * @param map
     */

    public void sortHashMapByValue(final HashMap<String, CustomData> map) {
        ArrayList<String> keys = new ArrayList<String>();
        keys.addAll(map.keySet());
        Collections.sort(keys, new Comparator<String>() {
            @Override
            public int compare(String lhs, String rhs) {
                CustomData val1 = map.get(lhs);
                CustomData val2 = map.get(rhs);
                if (val1 == null) {
                    return (val2 != null) ? 1 : 0;
                } else if (val1 != null) && (val2 != null)) {
                    return = val1.compareTo(val2);
                }
                else {
                    return 0;
                }
            }
        });

        for (String key : keys) {
            CustomData c = map.get(key);
            if (c != null) {
                Log.e("key:"+key+", CustomData:"+c.toString());
            } 
        }
    }

PostgreSQL: export resulting data from SQL query to Excel/CSV

This worked for me:

COPY (SELECT * FROM table) 
    TO E'C:\\Program Files (x86)\\PostgreSQL\\8.4\\data\\try.csv';

In my case the problem was with the writing permission to a special folder (though I work as administrator), after changing the path to the original data folder under PostgreSQL I had success.