Programs & Examples On #Dft

Discrete Fourier transform (DFT) is a specific kind of discrete transform, used in Fourier analysis.

Drop shadow for PNG image in CSS

As Dudley mentioned in his answer this is possible with the drop-shadow CSS filter for webkit, SVG for Firefox and DirectX filters for Internet Explorer 9-.

One step further is to inline the SVG, eliminating the extra request:

.shadowed {
    -webkit-filter: drop-shadow(12px 12px 25px rgba(0,0,0,0.5));
    filter: url("data:image/svg+xml;utf8,<svg height='0' xmlns='http://www.w3.org/2000/svg'><filter id='drop-shadow'><feGaussianBlur in='SourceAlpha' stdDeviation='4'/><feOffset dx='12' dy='12' result='offsetblur'/><feFlood flood-color='rgba(0,0,0,0.5)'/><feComposite in2='offsetblur' operator='in'/><feMerge><feMergeNode/><feMergeNode in='SourceGraphic'/></feMerge></filter></svg>#drop-shadow");
    -ms-filter: "progid:DXImageTransform.Microsoft.Dropshadow(OffX=12, OffY=12, Color='#444')";
    filter: "progid:DXImageTransform.Microsoft.Dropshadow(OffX=12, OffY=12, Color='#444')";
}

Converting a Pandas GroupBy output from Series to DataFrame

These solutions only partially worked for me because I was doing multiple aggregations. Here is a sample output of my grouped by that I wanted to convert to a dataframe:

Groupby Output

Because I wanted more than the count provided by reset_index(), I wrote a manual method for converting the image above into a dataframe. I understand this is not the most pythonic/pandas way of doing this as it is quite verbose and explicit, but it was all I needed. Basically, use the reset_index() method explained above to start a "scaffolding" dataframe, then loop through the group pairings in the grouped dataframe, retrieve the indices, perform your calculations against the ungrouped dataframe, and set the value in your new aggregated dataframe.

df_grouped = df[['Salary Basis', 'Job Title', 'Hourly Rate', 'Male Count', 'Female Count']]
df_grouped = df_grouped.groupby(['Salary Basis', 'Job Title'], as_index=False)

# Grouped gives us the indices we want for each grouping
# We cannot convert a groupedby object back to a dataframe, so we need to do it manually
# Create a new dataframe to work against
df_aggregated = df_grouped.size().to_frame('Total Count').reset_index()
df_aggregated['Male Count'] = 0
df_aggregated['Female Count'] = 0
df_aggregated['Job Rate'] = 0

def manualAggregations(indices_array):
    temp_df = df.iloc[indices_array]
    return {
        'Male Count': temp_df['Male Count'].sum(),
        'Female Count': temp_df['Female Count'].sum(),
        'Job Rate': temp_df['Hourly Rate'].max()
    }

for name, group in df_grouped:
    ix = df_grouped.indices[name]
    calcDict = manualAggregations(ix)

    for key in calcDict:
        #Salary Basis, Job Title
        columns = list(name)
        df_aggregated.loc[(df_aggregated['Salary Basis'] == columns[0]) & 
                          (df_aggregated['Job Title'] == columns[1]), key] = calcDict[key]

If a dictionary isn't your thing, the calculations could be applied inline in the for loop:

    df_aggregated['Male Count'].loc[(df_aggregated['Salary Basis'] == columns[0]) & 
                                (df_aggregated['Job Title'] == columns[1])] = df['Male Count'].iloc[ix].sum()

How to break out from foreach loop in javascript

Use a for loop instead of .forEach()

var myObj = [{"a": "1","b": null},{"a": "2","b": 5}]
var result = false

for(var call of myObj) {
    console.log(call)
    
    var a = call['a'], b = call['b']
     
    if(a == null || b == null) {
        result = false
        break
    }
}

The difference between "require(x)" and "import x"

new ES6:

'import' should be used with 'export' key words to share variables/arrays/objects between js files:

export default myObject;

//....in another file

import myObject from './otherFile.js';

old skool:

'require' should be used with 'module.exports'

 module.exports = myObject;

//....in another file

var myObject = require('./otherFile.js');

Responsive design with media query : screen size?

Here is media queries for common device breakpoints.

    /* Smartphones (portrait and landscape) ----------- */
@media only screen and (min-device-width : 320px) and (max-device-width : 480px) {
/* Styles */
}

/* Smartphones (landscape) ----------- */
@media only screen and (min-width : 321px) {
/* Styles */
}

/* Smartphones (portrait) ----------- */
@media only screen and (max-width : 320px) {
/* Styles */
}

/* iPads (portrait and landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) {
/* Styles */
}

/* iPads (landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) {
/* Styles */
}

/* iPads (portrait) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) {
/* Styles */
}
/**********
iPad 3
**********/
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}

@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}
/* Desktops and laptops ----------- */
@media only screen  and (min-width : 1224px) {
/* Styles */
}

/* Large screens ----------- */
@media only screen  and (min-width : 1824px) {
/* Styles */
}

/* iPhone 4 ----------- */
@media only screen and (min-device-width : 320px) and (max-device-width : 480px) and (orientation : landscape) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}

@media only screen and (min-device-width : 320px) and (max-device-width : 480px) and (orientation : portrait) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}

java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation

Many people have given a fix, so I'll talk about the source of the problem.

According to the exception log:

Caused by: java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation
    at android.app.Activity.onCreate(Activity.java:1081)
    at android.support.v4.app.SupportActivity.onCreate(SupportActivity.java:66)
    at android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:297)
    at android.support.v7.app.AppCompatActivity.onCreate(AppCompatActivity.java:84)
    at com.nut.blehunter.ui.DialogContainerActivity.onCreate(DialogContainerActivity.java:43)
    at android.app.Activity.performCreate(Activity.java:7372)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1218)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3147)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3302) 
    at android.app.ActivityThread.-wrap12(Unknown Source:0) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1891) 
    at android.os.Handler.dispatchMessage(Handler.java:108) 
    at android.os.Looper.loop(Looper.java:166)

The code that triggered the exception in Activity.java

    //Need to pay attention mActivityInfo.isFixedOrientation() and ActivityInfo.isTranslucentOrFloating(ta)
    if (getApplicationInfo().targetSdkVersion >= O_MR1 && mActivityInfo.isFixedOrientation()) {
        final TypedArray ta = obtainStyledAttributes(com.android.internal.R.styleable.Window);
        final boolean isTranslucentOrFloating = ActivityInfo.isTranslucentOrFloating(ta);
        ta.recycle();

        //Exception occurred
        if (isTranslucentOrFloating) {
            throw new IllegalStateException(
                    "Only fullscreen opaque activities can request orientation");
        }
    }

mActivityInfo.isFixedOrientation():

        /**
        * Returns true if the activity's orientation is fixed.
        * @hide
        */
        public boolean isFixedOrientation() {
            return isFixedOrientationLandscape() || isFixedOrientationPortrait()
                    || screenOrientation == SCREEN_ORIENTATION_LOCKED;
        }
        /**
        * Returns true if the activity's orientation is fixed to portrait.
        * @hide
        */
        boolean isFixedOrientationPortrait() {
            return isFixedOrientationPortrait(screenOrientation);
        }

        /**
        * Returns true if the activity's orientation is fixed to portrait.
        * @hide
        */
        public static boolean isFixedOrientationPortrait(@ScreenOrientation int orientation) {
            return orientation == SCREEN_ORIENTATION_PORTRAIT
                    || orientation == SCREEN_ORIENTATION_SENSOR_PORTRAIT
                    || orientation == SCREEN_ORIENTATION_REVERSE_PORTRAIT
                    || orientation == SCREEN_ORIENTATION_USER_PORTRAIT;
        }

        /**
        * Determines whether the {@link Activity} is considered translucent or floating.
        * @hide
        */
        public static boolean isTranslucentOrFloating(TypedArray attributes) {
            final boolean isTranslucent = attributes.getBoolean(com.android.internal.R.styleable.Window_windowIsTranslucent, false);
            final boolean isSwipeToDismiss = !attributes.hasValue(com.android.internal.R.styleable.Window_windowIsTranslucent)
                                            && attributes.getBoolean(com.android.internal.R.styleable.Window_windowSwipeToDismiss, false);
            final boolean isFloating = attributes.getBoolean(com.android.internal.R.styleable.Window_windowIsFloating, false);
            return isFloating || isTranslucent || isSwipeToDismiss;
        }

According to the above code analysis, when TargetSdkVersion>=27, when using SCREEN_ORIENTATION_LANDSCAPE, SCREEN_ORIENTATION_PORTRAIT, and other related attributes, the use of windowIsTranslucent, windowIsFloating, and windowSwipeToDismiss topic attributes will trigger an exception.

After the problem is found, you can change the TargetSdkVersion or remove the related attributes of the theme according to your needs.

Semaphore vs. Monitors - what's the difference?

Following explanation actually explains how wait() and signal() of monitor differ from P and V of semaphore.

The wait() and signal() operations on condition variables in a monitor are similar to P and V operations on counting semaphores.

A wait statement can block a process's execution, while a signal statement can cause another process to be unblocked. However, there are some differences between them. When a process executes a P operation, it does not necessarily block that process because the counting semaphore may be greater than zero. In contrast, when a wait statement is executed, it always blocks the process. When a task executes a V operation on a semaphore, it either unblocks a task waiting on that semaphore or increments the semaphore counter if there is no task to unlock. On the other hand, if a process executes a signal statement when there is no other process to unblock, there is no effect on the condition variable. Another difference between semaphores and monitors is that users awaken by a V operation can resume execution without delay. Contrarily, users awaken by a signal operation are restarted only when the monitor is unlocked. In addition, a monitor solution is more structured than the one with semaphores because the data and procedures are encapsulated in a single module and that the mutual exclusion is provided automatically by the implementation.

Link: here for further reading. Hope it helps.

ValueError: could not broadcast input array from shape (224,224,3) into shape (224,224)

I was facing the same problem because some of the images are grey scale images in my data set, so i solve my problem by doing this

    from PIL import Image
    img = Image.open('my_image.jpg').convert('RGB')
    # a line from my program
    positive_images_array = np.array([np.array(Image.open(img).convert('RGB').resize((150, 150), Image.ANTIALIAS)) for img in images_in_yes_directory])

Simple If/Else Razor Syntax

Just use this for the closing tag:

  @:</tr>

And leave your if/else as is.

Seems like the if statement doesn't wanna' work.

It works fine. You're working in 2 language-spaces here, it seems only proper not to split open/close sandwiches over the border.

How do I express "if value is not empty" in the VBA language?

Use Not IsEmpty().

For example:

Sub DoStuffIfNotEmpty()
    If Not IsEmpty(ActiveCell.Value) Then
        MsgBox "I'm not empty!"
    End If
End Sub

creating charts with angularjs

I've created an angular directive for xCharts which is a nice js chart library http://tenxer.github.io/xcharts/. You can install it using bower, quite easy: https://github.com/radu-cigmaian/ng-xCharts

Highcharts is also a solution, but it is not free for comercial use.

Finding the median of an unsorted array

The answer is "No, one can't find the median of an arbitrary, unsorted dataset in linear time". The best one can do as a general rule (as far as I know) is Median of Medians (to get a decent start), followed by Quickselect. Ref: [https://en.wikipedia.org/wiki/Median_of_medians][1]

SQL search multiple values in same field

This has been partially answered here: MySQL Like multiple values

I advise against

$search = explode( ' ', $search );

and input them directly into the SQL query as this makes prone to SQL inject via the search bar. You will have to escape the characters first in case they try something funny like: "--; DROP TABLE name;

$search = str_replace('"', "''", search );

But even that is not completely safe. You must try to use SQL prepared statements to be safer. Using the regular expression is much easier to build a function to prepare and create what you want.

function makeSQL_search_pattern($search) {
    search_pattern = false;
    //escape the special regex chars
    $search = str_replace('"', "''", $search);
    $search = str_replace('^', "\\^", $search);
    $search = str_replace('$', "\\$", $search);
    $search = str_replace('.', "\\.", $search);
    $search = str_replace('[', "\\[", $search);
    $search = str_replace(']', "\\]", $search);
    $search = str_replace('|', "\\|", $search);
    $search = str_replace('*', "\\*", $search);
    $search = str_replace('+', "\\+", $search);
    $search = str_replace('{', "\\{", $search);
    $search = str_replace('}', "\\}", $search);
    $search = explode(" ", $search);
    for ($i = 0; $i < count($search); $i++) {
        if ($i > 0 && $i < count($search) ) {
           $search_pattern .= "|";
        }
        $search_pattern .= $search[$i];
    }
    return search_pattern;
}

$search_pattern = makeSQL_search_pattern($search);
$sql_query = "SELECT name FROM Products WHERE name REGEXP :search LIMIT 6"
$stmt = pdo->prepare($sql_query);
$stmt->bindParam(":search", $search_pattern, PDO::PARAM_STR);
$stmt->execute();

I have not tested this code, but this is what I would do in your case. I hope this helps.

PHP - add 1 day to date format mm-dd-yyyy

use http://www.php.net/manual/en/datetime.add.php like

$date = date_create('2000-01-01');
date_add($date, date_interval_create_from_date_string('1 days'));
echo date_format($date, 'Y-m-d');

output

2000-01-2

MongoDB - Update objects in a document's array (nested updating)

There is no way to do this in single query. You have to search the document in first query:

If document exists:

db.bar.update( {user_id : 123456 , "items.item_name" : "my_item_two" } , 
                {$inc : {"items.$.price" : 1} } , 
                false , 
                true);

Else

db.bar.update( {user_id : 123456 } , 
                {$addToSet : {"items" : {'item_name' : "my_item_two" , 'price' : 1 }} } ,
                false , 
                true);

No need to add condition {$ne : "my_item_two" }.

Also in multithreaded enviourment you have to be careful that only one thread can execute the second (insert case, if document did not found) at a time, otherwise duplicate embed documents will be inserted.

Round float to x decimals?

The Mark Dickinson answer, although complete, didn't work with the float(52.15) case. After some tests, there is the solution that I'm using:

import decimal
        
def value_to_decimal(value, decimal_places):
    decimal.getcontext().rounding = decimal.ROUND_HALF_UP  # define rounding method
    return decimal.Decimal(str(float(value))).quantize(decimal.Decimal('1e-{}'.format(decimal_places)))

(The conversion of the 'value' to float and then string is very important, that way, 'value' can be of the type float, decimal, integer or string!)

Hope this helps anyone.

How to get domain URL and application name?

I would strongly suggest you to read through the docs, for similar methods. If you are interested in context path, have a look here, ServletContext.getContextPath().

Need to remove href values when printing in Chrome

_x000D_
_x000D_
@media print {_x000D_
   a[href]:after {_x000D_
      display: none;_x000D_
      visibility: hidden;_x000D_
   }_x000D_
}
_x000D_
_x000D_
_x000D_

Work's perfect.

How to color the Git console?

Another way is to edit the .gitconfig (create one if not exist), for instance:

vim ~/.gitconfig

and then add:

[color]
  diff = auto
  status = auto
  branch = auto

How to get the caller class in Java

This is the most efficient way to get just the callers class. Other approaches take an entire stack dump and only give you the class name.

However, this class in under sun.* which is really for internal use. This means that it may not work on other Java platforms or even other Java versions. You have to decide whether this is a problem or not.

struct in class

If you give the struct no name it will work

class E
{
public: 
    struct
    {
        int v;
    };
};

Otherwise write X x and write e.x.v

How to replace multiple substrings of a string?

Here is another way of doing it with a dictionary:

listA="The cat jumped over the house".split()
modify = {word:word for number,word in enumerate(listA)}
modify["cat"],modify["jumped"]="dog","walked"
print " ".join(modify[x] for x in listA)

Count the frequency that a value occurs in a dataframe column

In 0.18.1 groupby together with count does not give the frequency of unique values:

>>> df
   a
0  a
1  b
2  s
3  s
4  b
5  a
6  b

>>> df.groupby('a').count()
Empty DataFrame
Columns: []
Index: [a, b, s]

However, the unique values and their frequencies are easily determined using size:

>>> df.groupby('a').size()
a
a    2
b    3
s    2

With df.a.value_counts() sorted values (in descending order, i.e. largest value first) are returned by default.

Twitter Bootstrap 3: How to center a block

It's new in the Bootstrap 3.0.1 release, so make sure you have the latest (10/29)...

Demo: http://bootply.com/91632

_x000D_
_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<div class="row">_x000D_
    <div class="center-block" style="width:200px;background-color:#ccc;">...</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Center an element with "absolute" position and undefined width in CSS?

I understand this question already has a few answers, but I've never found a solution that would work in almost all classes that also makes sense and is elegant, so here's my take after tweaking a bunch:

_x000D_
_x000D_
.container {
    position: relative;
}

.container .cat-link {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate3d(-50%,-50%,0);
    z-index: 100;
    text-transform: uppercase; /* Forces CSS to treat this as text, not a texture, so no more blurry bugs */
    background-color: white;
}

.color-block {
  height: 250px;
  width: 100%;
  background-color: green;
}
_x000D_
<div class="container">
  <a class="cat-link" href="">Category</a>
  <div class="color-block"></div>
</div>
_x000D_
_x000D_
_x000D_

It is saying give me a top: 50% and a left: 50%, then transform (create space) on both the X/Y axis to the -50% value, in a sense "create a mirror space".

As such, this creates an equal space on all the four points of a div, which is always a box (has four sides).

This will:

  1. Work without having to know the parent's height / width.
  2. Work on responsive.
  3. Work on either X or Y axis. Or both, as in my example.
  4. I can't come up with a situation where it doesn't work.

How to detect if user select cancel InputBox VBA Excel

If the user clicks Cancel, a zero-length string is returned. You can't differentiate this from entering an empty string. You can however make your own custom InputBox class...

EDIT to properly differentiate between empty string and cancel, according to this answer.

Your example

Private Sub test()
    Dim result As String
    result = InputBox("Enter Date MM/DD/YYY", "Date Confirmation", Now)
    If StrPtr(result) = 0 Then
        MsgBox ("User canceled!")
    ElseIf result = vbNullString Then
        MsgBox ("User didn't enter anything!")
    Else
        MsgBox ("User entered " & result)
    End If
End Sub

Would tell the user they canceled when they delete the default string, or they click cancel.

See http://msdn.microsoft.com/en-us/library/6z0ak68w(v=vs.90).aspx

How to vertically align into the center of the content of a div with defined width/height?

I would say to add a paragraph with a period in it and style it like so:

<p class="center">.</p>

<style>
.center {font-size: 0px; margin-bottom: anyPercentage%;}
</style>

You may need to toy around with the percentages to get it right

Custom date format with jQuery validation plugin

$.validator.addMethod("mydate", function (value, element) {

        return this.optional(element) || /^(\d{4})(-|\/)(([0-1]{1})([1-2]{1})|([0]{1})([0-9]{1}))(-|\/)(([0-2]{1})([1-9]{1})|([3]{1})([0-1]{1}))/.test(value);

    });

you can input like yyyy-mm-dd also yyyy/mm/dd

but can't judge the the size of the month sometime Feb just 28 or 29 days.

How to append rows in a pandas dataframe in a for loop?

A more compact and efficient way would be perhaps:

cols = ['frame', 'count']
N = 4
dat = pd.DataFrame(columns = cols)
for i in range(N):

    dat = dat.append({'frame': str(i), 'count':i},ignore_index=True)

output would be:

>>> dat
   frame count
0     0     0
1     1     1
2     2     2
3     3     3

Lists in ConfigParser

import ConfigParser
import os

class Parser(object):
    """attributes may need additional manipulation"""
    def __init__(self, section):
        """section to retun all options on, formatted as an object
        transforms all comma-delimited options to lists
        comma-delimited lists with colons are transformed to dicts
        dicts will have values expressed as lists, no matter the length
        """
        c = ConfigParser.RawConfigParser()
        c.read(os.path.join(os.path.dirname(__file__), 'config.cfg'))

        self.section_name = section

        self.__dict__.update({k:v for k, v in c.items(section)})

        #transform all ',' into lists, all ':' into dicts
        for key, value in self.__dict__.items():
            if value.find(':') > 0:
                #dict
                vals = value.split(',')
                dicts = [{k:v} for k, v in [d.split(':') for d in vals]]
                merged = {}
                for d in dicts:
                    for k, v in d.items():
                        merged.setdefault(k, []).append(v)
                self.__dict__[key] = merged
            elif value.find(',') > 0:
                #list
                self.__dict__[key] = value.split(',')

So now my config.cfg file, which could look like this:

[server]
credentials=username:admin,password:$3<r3t
loggingdirs=/tmp/logs,~/logs,/var/lib/www/logs
timeoutwait=15

Can be parsed into fine-grained-enough objects for my small project.

>>> import config
>>> my_server = config.Parser('server')
>>> my_server.credentials
{'username': ['admin'], 'password', ['$3<r3t']}
>>> my_server.loggingdirs:
['/tmp/logs', '~/logs', '/var/lib/www/logs']
>>> my_server.timeoutwait
'15'

This is for very quick parsing of simple configs, you lose all ability to fetch ints, bools, and other types of output without either transforming the object returned from Parser, or re-doing the parsing job accomplished by the Parser class elsewhere.

Disable Required validation attribute under certain circumstances

I was looking for a solution where I can use the same model for an insert and update in web api. In my situation is this always a body content. The [Requiered] attributes must be skipped if it is an update method. In my solution, you place an attribute [IgnoreRequiredValidations] above the method. This is as follows:

public class WebServiceController : ApiController
{
    [HttpPost]
    public IHttpActionResult Insert(SameModel model)
    {
        ...
    }

    [HttpPut]
    [IgnoreRequiredValidations]
    public IHttpActionResult Update(SameModel model)
    {
        ...
    }

    ...

What else needs to be done? An own BodyModelValidator must becreated and added at the startup. This is in the HttpConfiguration and looks like this: config.Services.Replace(typeof(IBodyModelValidator), new IgnoreRequiredOrDefaultBodyModelValidator());

using Owin;
using your_namespace.Web.Http.Validation;

[assembly: OwinStartup(typeof(your_namespace.Startup))]

namespace your_namespace
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            Configuration(app, new HttpConfiguration());
        }

        public void Configuration(IAppBuilder app, HttpConfiguration config)
        {
            config.Services.Replace(typeof(IBodyModelValidator), new IgnoreRequiredOrDefaultBodyModelValidator());
        }

        ...

My own BodyModelValidator is derived from the DefaultBodyModelValidator. And i figure out that i had to override the 'ShallowValidate' methode. In this override i filter the requierd model validators. And now the IgnoreRequiredOrDefaultBodyModelValidator class and the IgnoreRequiredValidations attributte class:

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Web.Http.Controllers;
using System.Web.Http.Metadata;
using System.Web.Http.Validation;

namespace your_namespace.Web.Http.Validation
{
    public class IgnoreRequiredOrDefaultBodyModelValidator : DefaultBodyModelValidator
    {
        private static ConcurrentDictionary<HttpActionBinding, bool> _ignoreRequiredValidationByActionBindingCache;

        static IgnoreRequiredOrDefaultBodyModelValidator()
        {
            _ignoreRequiredValidationByActionBindingCache = new ConcurrentDictionary<HttpActionBinding, bool>();
        }

        protected override bool ShallowValidate(ModelMetadata metadata, BodyModelValidatorContext validationContext, object container, IEnumerable<ModelValidator> validators)
        {
            var actionContext = validationContext.ActionContext;

            if (RequiredValidationsIsIgnored(actionContext.ActionDescriptor.ActionBinding))
                validators = validators.Where(v => !v.IsRequired);          

            return base.ShallowValidate(metadata, validationContext, container, validators);
        }

        #region RequiredValidationsIsIgnored
        private bool RequiredValidationsIsIgnored(HttpActionBinding actionBinding)
        {
            bool ignore;

            if (!_ignoreRequiredValidationByActionBindingCache.TryGetValue(actionBinding, out ignore))
                _ignoreRequiredValidationByActionBindingCache.TryAdd(actionBinding, ignore = RequiredValidationsIsIgnored(actionBinding.ActionDescriptor as ReflectedHttpActionDescriptor));

            return ignore;
        }

        private bool RequiredValidationsIsIgnored(ReflectedHttpActionDescriptor actionDescriptor)
        {
            if (actionDescriptor == null)
                return false;

            return actionDescriptor.MethodInfo.GetCustomAttribute<IgnoreRequiredValidationsAttribute>(false) != null;
        } 
        #endregion
    }

    [AttributeUsage(AttributeTargets.Method, Inherited = true)]
    public class IgnoreRequiredValidationsAttribute : Attribute
    {

    }
}

Sources:

Passing variables to the next middleware using next() in Express.js

The trick is pretty simple... The request cycle is still pretty much alive. You can just add a new variable that will create a temporary, calling

app.get('some/url/endpoint', middleware1, middleware2);

Since you can handle your request in the first middleware

(req, res, next) => {
    var yourvalue = anyvalue
}

In middleware 1 you handle your logic and store your value like below:

req.anyvariable = yourvalue

In middleware 2 you can catch this value from middleware 1 doing the following:

(req, res, next) => {
    var storedvalue = req.yourvalue
}

Download file inside WebView

Try using download manager, which can help you download everything you want and save you time.

Check those to options:

Option 1 ->

 mWebView.setDownloadListener(new DownloadListener() {
        public void onDownloadStart(String url, String userAgent,
                String contentDisposition, String mimetype,
                long contentLength) {
 Request request = new Request(
                            Uri.parse(url));
                    request.allowScanningByMediaScanner();
                    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                    request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "download"); 
                    DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
                    dm.enqueue(request);        

        }
    });

Option 2 ->

if(mWebview.getUrl().contains(".mp3") {
 Request request = new Request(
                        Uri.parse(url));
                request.allowScanningByMediaScanner();
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "download"); 
// You can change the name of the downloads, by changing "download" to everything you want, such as the mWebview title...
                DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
                dm.enqueue(request);        

    }

Add a column with a default value to an existing table in SQL Server

This has a lot of answers, but I feel the need to add this extended method. This seems a lot longer, but it is extremely useful if you're adding a NOT NULL field to a table with millions of rows in an active database.

ALTER TABLE {schemaName}.{tableName}
    ADD {columnName} {datatype} NULL
    CONSTRAINT {constraintName} DEFAULT {DefaultValue}

UPDATE {schemaName}.{tableName}
    SET {columnName} = {DefaultValue}
    WHERE {columName} IS NULL

ALTER TABLE {schemaName}.{tableName}
    ALTER COLUMN {columnName} {datatype} NOT NULL

What this will do is add the column as a nullable field and with the default value, update all fields to the default value (or you can assign more meaningful values), and finally it will change the column to be NOT NULL.

The reason for this is if you update a large scale table and add a new not null field it has to write to every single row and hereby will lock out the entire table as it adds the column and then writes all the values.

This method will add the nullable column which operates a lot faster by itself, then fills the data before setting the not null status.

I've found that doing the entire thing in one statement will lock out one of our more active tables for 4-8 minutes and quite often I have killed the process. This method each part usually takes only a few seconds and causes minimal locking.

Additionally, if you have a table in the area of billions of rows it may be worth batching the update like so:

WHILE 1=1
BEGIN
    UPDATE TOP (1000000) {schemaName}.{tableName}
        SET {columnName} = {DefaultValue}
        WHERE {columName} IS NULL

    IF @@ROWCOUNT < 1000000
        BREAK;
END

What is the "Illegal Instruction: 4" error and why does "-mmacosx-version-min=10.x" fix it?

I found my issue was an improper
if (leaf = NULL) {...}
where it should have been
if (leaf == NULL){...}

Check those compiler warnings!

Javascript string replace with regex to strip off illegal characters

Put them in brackets []:

var cleanString = dirtyString.replace(/[\|&;\$%@"<>\(\)\+,]/g, "");

Can an Android App connect directly to an online mysql database

Look at this online backend.

Parse.com

They offer push notifications, social integration, data storage, and the ability to add rich custom logic to your app’s backend with Cloud Code.

Can I use Objective-C blocks as properties?

Here's an example of how you would accomplish such a task:

#import <Foundation/Foundation.h>
typedef int (^IntBlock)();

@interface myobj : NSObject
{
    IntBlock compare;
}

@property(readwrite, copy) IntBlock compare;

@end

@implementation myobj

@synthesize compare;

- (void)dealloc 
{
   // need to release the block since the property was declared copy. (for heap
   // allocated blocks this prevents a potential leak, for compiler-optimized 
   // stack blocks it is a no-op)
   // Note that for ARC, this is unnecessary, as with all properties, the memory management is handled for you.
   [compare release];
   [super dealloc];
}
@end

int main () {
    @autoreleasepool {
        myobj *ob = [[myobj alloc] init];
        ob.compare = ^
        {
            return rand();
        };
        NSLog(@"%i", ob.compare());
        // if not ARC
        [ob release];
    }

    return 0;
}

Now, the only thing that would need to change if you needed to change the type of compare would be the typedef int (^IntBlock)(). If you need to pass two objects to it, change it to this: typedef int (^IntBlock)(id, id), and change your block to:

^ (id obj1, id obj2)
{
    return rand();
};

I hope this helps.

EDIT March 12, 2012:

For ARC, there are no specific changes required, as ARC will manage the blocks for you as long as they are defined as copy. You do not need to set the property to nil in your destructor, either.

For more reading, please check out this document: http://clang.llvm.org/docs/AutomaticReferenceCounting.html

Python FileNotFound

try block should be around open. Not around prompt.

while True:
    prompt = input("\n Hello to Sudoku valitator,"
    "\n \n Please type in the path to your file and press 'Enter': ")
    try:
        sudoku = open(prompt, 'r').readlines()
    except FileNotFoundError:
        print("Wrong file or file path")
    else:
        break

Seaborn plots not showing up

To tell from the style of your code snippet, I suppose you were using IPython rather than Jupyter Notebook.

In this issue on GitHub, it was made clear by a member of IPython in 2016 that the display of charts would only work when "only work when it's a Jupyter kernel". Thus, the %matplotlib inline would not work.

I was just having the same issue and suggest you use Jupyter Notebook for the visualization.

What is the height of iPhone's onscreen keyboard?

I can't find latest answer, so I check it all with simulator.(iOS 11.0)


Device | Screen Height | Portrait | Landscape

iPhone 4s | 480.0 | 216.0 | 162.0

iPhone 5, iPhone 5s, iPhone SE | 568.0 | 216.0 | 162.0

iPhone 6, iPhone 6s, iPhone 7, iPhone 8, iPhone X | 667.0 | 216.0 | 162.0

iPhone 6 plus, iPhone 7 plus, iPhone 8 plus | 736.0 | 226.0 | 162.0

iPad 5th generation, iPad Air, iPad Air 2, iPad Pro 9.7, iPad Pro 10.5, iPad Pro 12.9 | 1024.0 | 265.0 | 353.0


Thanks!

How do I tell what type of value is in a Perl variable?

A scalar always holds a single element. Whatever is in a scalar variable is always a scalar. A reference is a scalar value.

If you want to know if it is a reference, you can use ref. If you want to know the reference type, you can use the reftype routine from Scalar::Util.

If you want to know if it is an object, you can use the blessed routine from Scalar::Util. You should never care what the blessed package is, though. UNIVERSAL has some methods to tell you about an object: if you want to check that it has the method you want to call, use can; if you want to see that it inherits from something, use isa; and if you want to see it the object handles a role, use DOES.

If you want to know if that scalar is actually just acting like a scalar but tied to a class, try tied. If you get an object, continue your checks.

If you want to know if it looks like a number, you can use looks_like_number from Scalar::Util. If it doesn't look like a number and it's not a reference, it's a string. However, all simple values can be strings.

If you need to do something more fancy, you can use a module such as Params::Validate.

Jquery split function

Javascript String objects have a split function, doesn't really need to be jQuery specific

 var str = "nice.test"
 var strs = str.split(".")

strs would be

 ["nice", "test"]

I'd be tempted to use JSON in your example though. The php could return the JSON which could easily be parsed

 success: function(data) {
   var items = JSON.parse(data)
 }

POST data in JSON format

Not sure if you want jQuery.

var form;

form.onsubmit = function (e) {
  // stop the regular form submission
  e.preventDefault();

  // collect the form data while iterating over the inputs
  var data = {};
  for (var i = 0, ii = form.length; i < ii; ++i) {
    var input = form[i];
    if (input.name) {
      data[input.name] = input.value;
    }
  }

  // construct an HTTP request
  var xhr = new XMLHttpRequest();
  xhr.open(form.method, form.action, true);
  xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8');

  // send the collected data as JSON
  xhr.send(JSON.stringify(data));

  xhr.onloadend = function () {
    // done
  };
};

Spring Bean Scopes

Just want to update, that in Spring 5, as mentioned in Spring docs, Spring supports 6 scopes, four of which are available only if you use a web-aware ApplicationContext.

singleton (Default) Scopes a single bean definition to a single object instance per Spring IoC container.

prototype Scopes a single bean definition to any number of object instances.

request Scopes a single bean definition to the lifecycle of a single HTTP request; that is, each HTTP request has its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext.

session Scopes a single bean definition to the lifecycle of an HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext.

application Scopes a single bean definition to the lifecycle of a ServletContext. Only valid in the context of a web-aware Spring ApplicationContext.

websocket Scopes a single bean definition to the lifecycle of a WebSocket. Only valid in the context of a web-aware Spring ApplicationContext.

openssl s_client using a proxy

Even with openssl v1.1.0 I had some problems passing our proxy, e.g. s_client: HTTP CONNECT failed: 400 Bad Request That forced me to write a minimal Java-class to show the SSL-Handshake

    public static void main(String[] args) throws IOException, URISyntaxException {
    HttpHost proxy = new HttpHost("proxy.my.company", 8080);
    DefaultProxyRoutePlanner routePlanner = new DefaultProxyRoutePlanner(proxy);
    CloseableHttpClient httpclient = HttpClients.custom()
            .setRoutePlanner(routePlanner)
            .build();
    URI uri = new URIBuilder()
            .setScheme("https")
            .setHost("www.myhost.com")
            .build();
    HttpGet httpget = new HttpGet(uri);
    httpclient.execute(httpget);
}

With following dependency:

    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.5.2</version>
        <type>jar</type>
    </dependency>

you can run it with Java SSL Logging turned on

This should produce nice output like

trustStore provider is :
init truststore
adding as trusted cert:
  Subject: CN=Equifax Secure Global eBusiness CA-1, O=Equifax Secure Inc., C=US
  Issuer:  CN=Equifax Secure Global eBusiness CA-1, O=Equifax Secure Inc., C=US
  Algorithm: RSA; Serial number: 0xc3517
  Valid from Mon Jun 21 06:00:00 CEST 1999 until Mon Jun 22 06:00:00 CEST 2020

adding as trusted cert:
  Subject: CN=SecureTrust CA, O=SecureTrust Corporation, C=US
  Issuer:  CN=SecureTrust CA, O=SecureTrust Corporation, C=US
(....)

Google Chrome Printing Page Breaks

I just wanted to note here that Chrome also ignores page-break-* css settings in divs that have been floated.

I suspect there is a sound justification for this somewhere in the css spec, but I figured noting it might help someone someday ;-)

Just another note: IE7 can't acknowledge page break settings without an explicit height on the previous block element:

http://social.msdn.microsoft.com/forums/en-US/iewebdevelopment/thread/fe523ec6-2f01-41df-a31d-9ba93f21787b/

Add a new item to recyclerview programmatically?

if you are adding multiple items to the list use this:

mAdapter.notifyItemRangeInserted(startPosition, itemcount);

This notify any registered observers that the currently reflected itemCount items starting at positionStart have been newly inserted. The item previously located at positionStart and beyond can now be found starting at position positinStart+itemCount

existing item in the dataset still considered up to date.

How to send multiple data fields via Ajax?

Try with quotes:

data: {"status": status, "name": name}

It must work fine.

Accessing JPEG EXIF rotation data in JavaScript on the client side

If you only want the orientation tag and nothing else and don't like to include another huge javascript library I wrote a little code that extracts the orientation tag as fast as possible (It uses DataView and readAsArrayBuffer which are available in IE10+, but you can write your own data reader for older browsers):

_x000D_
_x000D_
function getOrientation(file, callback) {_x000D_
    var reader = new FileReader();_x000D_
    reader.onload = function(e) {_x000D_
_x000D_
        var view = new DataView(e.target.result);_x000D_
        if (view.getUint16(0, false) != 0xFFD8)_x000D_
        {_x000D_
            return callback(-2);_x000D_
        }_x000D_
        var length = view.byteLength, offset = 2;_x000D_
        while (offset < length) _x000D_
        {_x000D_
            if (view.getUint16(offset+2, false) <= 8) return callback(-1);_x000D_
            var marker = view.getUint16(offset, false);_x000D_
            offset += 2;_x000D_
            if (marker == 0xFFE1) _x000D_
            {_x000D_
                if (view.getUint32(offset += 2, false) != 0x45786966) _x000D_
                {_x000D_
                    return callback(-1);_x000D_
                }_x000D_
_x000D_
                var little = view.getUint16(offset += 6, false) == 0x4949;_x000D_
                offset += view.getUint32(offset + 4, little);_x000D_
                var tags = view.getUint16(offset, little);_x000D_
                offset += 2;_x000D_
                for (var i = 0; i < tags; i++)_x000D_
                {_x000D_
                    if (view.getUint16(offset + (i * 12), little) == 0x0112)_x000D_
                    {_x000D_
                        return callback(view.getUint16(offset + (i * 12) + 8, little));_x000D_
                    }_x000D_
                }_x000D_
            }_x000D_
            else if ((marker & 0xFF00) != 0xFF00)_x000D_
            {_x000D_
                break;_x000D_
            }_x000D_
            else_x000D_
            { _x000D_
                offset += view.getUint16(offset, false);_x000D_
            }_x000D_
        }_x000D_
        return callback(-1);_x000D_
    };_x000D_
    reader.readAsArrayBuffer(file);_x000D_
}_x000D_
_x000D_
// usage:_x000D_
var input = document.getElementById('input');_x000D_
input.onchange = function(e) {_x000D_
    getOrientation(input.files[0], function(orientation) {_x000D_
        alert('orientation: ' + orientation);_x000D_
    });_x000D_
}
_x000D_
<input id='input' type='file' />
_x000D_
_x000D_
_x000D_

values:

-2: not jpeg
-1: not defined

enter image description here

For those using Typescript, you can use the following code:

export const getOrientation = (file: File, callback: Function) => {
  var reader = new FileReader();

  reader.onload = (event: ProgressEvent) => {

    if (! event.target) {
      return;
    }

    const file = event.target as FileReader;
    const view = new DataView(file.result as ArrayBuffer);

    if (view.getUint16(0, false) != 0xFFD8) {
        return callback(-2);
    }

    const length = view.byteLength
    let offset = 2;

    while (offset < length)
    {
        if (view.getUint16(offset+2, false) <= 8) return callback(-1);
        let marker = view.getUint16(offset, false);
        offset += 2;

        if (marker == 0xFFE1) {
          if (view.getUint32(offset += 2, false) != 0x45786966) {
            return callback(-1);
          }

          let little = view.getUint16(offset += 6, false) == 0x4949;
          offset += view.getUint32(offset + 4, little);
          let tags = view.getUint16(offset, little);
          offset += 2;
          for (let i = 0; i < tags; i++) {
            if (view.getUint16(offset + (i * 12), little) == 0x0112) {
              return callback(view.getUint16(offset + (i * 12) + 8, little));
            }
          }
        } else if ((marker & 0xFF00) != 0xFF00) {
            break;
        }
        else {
            offset += view.getUint16(offset, false);
        }
    }
    return callback(-1);
  };

  reader.readAsArrayBuffer(file);
}

How do I jump out of a foreach loop in C#?

var ind=0;
foreach(string s in sList){
    if(s.equals("ok")){
        return true;
    }
    ind++;
}
if (ind==sList.length){
    return false;
}

Go Back to Previous Page

Try this:

$previous = "javascript:history.go(-1)";
if(isset($_SERVER['HTTP_REFERER'])) {
    $previous = $_SERVER['HTTP_REFERER'];
}

in html:

<a href="<?= $previous ?>">Back</a>

The JavaScript code is initialize as fallback for HTTP_REFERER variable sometimes not work.

How do I clear the dropdownlist values on button click event using jQuery?

If you want to reset the selected options

$('select option:selected').removeAttr('selected');

If you actually want to remove the options (although I don't think you mean this).

$('select').empty();

Substitute select for the most appropriate selector in your case (this may be by id or by CSS class). Using as is will reset all <select> elements on the page

How to silence output in a Bash script?

Try with:

myprogram &>/dev/null

to get no output

Spring: @Component versus @Bean

Additional Points from above answers

Let’s say we got a module which is shared in multiple apps and it contains a few services. Not all are needed for each app.

If use @Component on those service classes and the component scan in the application,

we might end up detecting more beans than necessary

In this case, you either had to adjust the filtering of the component scan or provide the configuration that even the unused beans can run. Otherwise, the application context won’t start.

In this case, it is better to work with @Bean annotation and only instantiate those beans,

which are required individually in each app

So, essentially, use @Bean for adding third-party classes to the context. And @Component if it is just inside your single application.

Assert equals between 2 Lists in Junit

if you don't want to build up an array list , you can try this also

@Test
public void test_array_pass()
{
  List<String> list = Arrays.asList("fee", "fi", "foe");
  Strint listToString = list.toString();
  Assert.assertTrue(listToString.contains("[fee, fi, foe]"));   // passes  
}

How to send post request to the below post method using postman rest client

  1. Open Postman.
  2. Enter URL in the URL bar http://{server:port}/json/metallica/post.
  3. Click Headers button and enter Content-Type as header and application/json in value.
  4. Select POST from the dropdown next to the URL text box.
  5. Select raw from the buttons available below URL text box.
  6. Select JSON from the following dropdown.
  7. In the textarea available below, post your request object:

    {
     "title" : "test title",
     "singer" : "some singer"
    }
    
  8. Hit Send.

  9. Refer to screenshot below: enter image description here

Adding headers when using httpClient.GetAsync

You can add whatever headers you need to the HttpClient.

Here is a nice tutorial about it.

This doesn't just reference to POST-requests, you can also use it for GET-requests.

How to auto-format code in Eclipse?

Notice: It did not format the document unless I corrected all mistakes. Check your file before pressing CTRLSHIFTF.

Java code for getting current time

tl;dr

Instant.now()  // UTC

…or…

ZonedDateTime.now(
    // Specify time zone.
    ZoneId.of( "Pacific/Auckland" )
)  

Details

The bundled java.util.Date/.Calendar classes are notoriously troublesome. Avoid them. They are now legacy, supplanted by the java.time framework.

Instead, use either:

java.time

ZonedDateTime zdt = ZonedDateTime.now();

If needed for old code, convert to java.util.Date. Go through at Instant which is a moment on the timeline in UTC.

java.util.Date date = java.util.Date.from( zdt.toInstant() );

Time Zone

Better to specify explicitly your desired/expected time zone rather than rely implicitly on the JVM’s current default time zone.

ZoneId zoneId = ZoneId.of( "America/Montreal" );
ZonedDateTime zdt = ZonedDateTime.now( zoneId );  // Pass desired/expected time zone.

Table of date-time types in Java, both modern and legacy

Joda-Time

FYI, the Joda-Time project is now in maintenance mode, with the team advising migration to the java.time classes.

DateTime now = DateTime.now();

To convert from a Joda-Time DateTime object to a java.util.Date for inter-operating with other classes…

java.util.Date date = now.toDate();

Search StackOverflow before posting. Your question has already been asked and answered.


About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

Table of which java.time library to use with which version of Java or Android

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

JQuery .on() method with multiple event handlers to one selector

I learned something really useful and fundamental from here.

chaining functions is very usefull in this case which works on most jQuery Functions including on function output too.

It works because output of most jQuery functions are the input objects sets so you can use them right away and make it shorter and smarter

function showPhotos() {
    $(this).find("span").slideToggle();
}

$(".photos")
    .on("mouseenter", "li", showPhotos)
    .on("mouseleave", "li", showPhotos);

Search All Fields In All Tables For A Specific Value (Oracle)

I modified Flood's script to execute once for each table rather than for every column of each table for faster execution. It requires Oracle 11g or greater.

    set serveroutput on size 100000

declare
    v_match_count integer;
    v_counter integer;

    -- The owner of the tables to search through (case-sensitive)
    v_owner varchar2(255) := 'OWNER_NAME';
    -- A string that is part of the data type(s) of the columns to search through (case-insensitive)
    v_data_type varchar2(255) := 'CHAR';
    -- The string to be searched for (case-insensitive)
    v_search_string varchar2(4000) := 'FIND_ME';

    -- Store the SQL to execute for each table in a CLOB to get around the 32767 byte max size for a VARCHAR2 in PL/SQL
    v_sql clob := '';
begin
    for cur_tables in (select owner, table_name from all_tables where owner = v_owner and table_name in 
                       (select table_name from all_tab_columns where owner = all_tables.owner and data_type like '%' ||  upper(v_data_type) || '%')
                       order by table_name) loop
        v_counter := 0;
        v_sql := '';

        for cur_columns in (select column_name from all_tab_columns where 
                            owner = v_owner and table_name = cur_tables.table_name and data_type like '%' || upper(v_data_type) || '%') loop
            if v_counter > 0 then
                v_sql := v_sql || ' or ';
            end if;
            v_sql := v_sql || 'upper(' || cur_columns.column_name || ') like ''%' || upper(v_search_string) || '%''';
            v_counter := v_counter + 1;
        end loop;

        v_sql := 'select count(*) from ' || cur_tables.table_name || ' where ' || v_sql;

        execute immediate v_sql
        into v_match_count;

        if v_match_count > 0 then
            dbms_output.put_line('Match in ' || cur_tables.owner || ': ' || cur_tables.table_name || ' - ' || v_match_count || ' records');
        end if;
    end loop;

    exception
        when others then
            dbms_output.put_line('Error when executing the following: ' || dbms_lob.substr(v_sql, 32600));
end;
/

Why won't bundler install JSON gem?

Switch ruby version from 1.9 to 2.2 with rvm did the job for me

Calculating a 2D Vector's Cross Product

Implementation 1 returns the magnitude of the vector that would result from a regular 3D cross product of the input vectors, taking their Z values implicitly as 0 (i.e. treating the 2D space as a plane in the 3D space). The 3D cross product will be perpendicular to that plane, and thus have 0 X & Y components (thus the scalar returned is the Z value of the 3D cross product vector).

Note that the magnitude of the vector resulting from 3D cross product is also equal to the area of the parallelogram between the two vectors, which gives Implementation 1 another purpose. In addition, this area is signed and can be used to determine whether rotating from V1 to V2 moves in an counter clockwise or clockwise direction. It should also be noted that implementation 1 is the determinant of the 2x2 matrix built from these two vectors.

Implementation 2 returns a vector perpendicular to the input vector still in the same 2D plane. Not a cross product in the classical sense but consistent in the "give me a perpendicular vector" sense.

Note that 3D euclidean space is closed under the cross product operation--that is, a cross product of two 3D vectors returns another 3D vector. Both of the above 2D implementations are inconsistent with that in one way or another.

Hope this helps...

How do you reverse a string in place in JavaScript?

var reverseString = function(str){ 
  let length = str.length - 1;
  str = str.split('');

  for(let i=0;i<= length;i++){
    str[length + i + 1] = str[length - i];
  }

  return str.splice(length + 1).join('');
}

Polynomial time and exponential time

Below are some common Big-O functions while analyzing algorithms.

  • O(1) - constant time
  • O(log(n)) - logarithmic time
  • O((log(n))c) - polylogarithmic time
  • O(n) - linear time
  • O(n2) - quadratic time
  • O(nc) - polynomial time
  • O(cn) - exponential time
  • O(n!) - factorial time

(n = size of input, c = some constant)

Here is the model graph representing Big-O complexity of some functions

graph model

cheers :-)

graph credits http://bigocheatsheet.com/

Arrays vs Vectors: Introductory Similarities and Differences

I'll add that arrays are very low-level constructs in C++ and you should try to stay away from them as much as possible when "learning the ropes" -- even Bjarne Stroustrup recommends this (he's the designer of C++).

Vectors come very close to the same performance as arrays, but with a great many conveniences and safety features. You'll probably start using arrays when interfacing with API's that deal with raw arrays, or when building your own collections.

How to save the output of a console.log(object) to a file?

You can use library l2i (https://github.com/seriyvolk83/logs2indexeddb) to save all you put into console.log and then invoke

l2i.download();

to download a file with logs.

Problems with local variable scope. How to solve it?

I found this approach useful. This way you do not need a class nor final

 btnInsert.addMouseListener(new MouseAdapter() {
        private Statement _statement;

        public MouseAdapter setStatement(Statement _stmnt)
        {
            _statement = _stmnt;
            return this;
        }
        @Override
        public void mouseDown(MouseEvent e) {
            String name = text.getText();
            String from = text_1.getText();
            String to = text_2.getText();
            String price = text_3.getText();

            String query = "INSERT INTO booking (name, fromst, tost, price) VALUES ('"+name+"', '"+from+"', '"+to+"', '"+price+"')";
            try {
                _statement.executeUpdate(query);
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }
    }.setStatement(statement));

Highlight the difference between two strings in PHP

I had terrible trouble with the both the PEAR-based and the simpler alternatives shown. So here's a solution that leverages the Unix diff command (obviously, you have to be on a Unix system or have a working Windows diff command for it to work). Choose your favourite temporary directory, and change the exceptions to return codes if you prefer.

/**
 * @brief Find the difference between two strings, lines assumed to be separated by "\n|
 * @param $new string The new string
 * @param $old string The old string
 * @return string Human-readable output as produced by the Unix diff command,
 * or "No changes" if the strings are the same.
 * @throws Exception
 */
public static function diff($new, $old) {
  $tempdir = '/var/somewhere/tmp'; // Your favourite temporary directory
  $oldfile = tempnam($tempdir,'OLD');
  $newfile = tempnam($tempdir,'NEW');
  if (!@file_put_contents($oldfile,$old)) {
    throw new Exception('diff failed to write temporary file: ' . 
         print_r(error_get_last(),true));
  }
  if (!@file_put_contents($newfile,$new)) {
    throw new Exception('diff failed to write temporary file: ' . 
         print_r(error_get_last(),true));
  }
  $answer = array();
  $cmd = "diff $newfile $oldfile";
  exec($cmd, $answer, $retcode);
  unlink($newfile);
  unlink($oldfile);
  if ($retcode != 1) {
    throw new Exception('diff failed with return code ' . $retcode);
  }
  if (empty($answer)) {
    return 'No changes';
  } else {
    return implode("\n", $answer);
  }
}

TS1086: An accessor cannot be declared in ambient context

Setting "skipLibCheck": true in tsconfig.json solved my problem

"compilerOptions": {
    "skipLibCheck": true
}

SUM of grouped COUNT in SQL Query

Try this:

SELECT  ISNULL(Name,'SUM'), count(*) as Count
FROM table_name
Group By Name
WITH ROLLUP

SQL Server AS statement aliased column within WHERE statement

Both accepted answer and Logical Processing Order explain why you could not do what you proposed.

Possible solution:

  • use derived table (cte/subquery)
  • use expression in WHERE
  • create view/computed column

From SQL Server 2008 you could use APPLY operator combined with Table valued Constructor:

SELECT *, s.distance
FROM poi_table 
CROSS APPLY (VALUES(6371*1000*acos(cos(radians(42.3936868308))*cos(radians(lat))*cos(radians(lon)-radians(-72.5277256966))+sin(radians(42.3936868308))*sin(radians(lat))))) AS s(distance)
WHERE distance < 500;

LiveDemo

Foreign keys in mongo?

You may be interested in using a ORM like Mongoid or MongoMapper.

http://mongoid.org/docs/relations/referenced/1-n.html

In a NoSQL database like MongoDB there are not 'tables' but collections. Documents are grouped inside Collections. You can have any kind of document – with any kind of data – in a single collection. Basically, in a NoSQL database it is up to you to decide how to organise the data and its relations, if there are any.

What Mongoid and MongoMapper do is to provide you with convenient methods to set up relations quite easily. Check out the link I gave you and ask any thing.

Edit:

In mongoid you will write your scheme like this:

class Student
  include Mongoid::Document

    field :name
    embeds_many :addresses
    embeds_many :scores    
end

class Address
  include Mongoid::Document

    field :address
    field :city
    field :state
    field :postalCode
    embedded_in :student
end

class Score
  include Mongoid::Document

    belongs_to :course
    field :grade, type: Float
    embedded_in :student
end


class Course
  include Mongoid::Document

  field :name
  has_many :scores  
end

Edit:

> db.foo.insert({group:"phones"})
> db.foo.find()                  
{ "_id" : ObjectId("4df6539ae90592692ccc9940"), "group" : "phones" }
{ "_id" : ObjectId("4df6540fe90592692ccc9941"), "group" : "phones" }
>db.foo.find({'_id':ObjectId("4df6539ae90592692ccc9940")}) 
{ "_id" : ObjectId("4df6539ae90592692ccc9940"), "group" : "phones" }

You can use that ObjectId in order to do relations between documents.

How can I disable notices and warnings in PHP within the .htaccess file?

Use:

ini_set('display_errors','off');

It is working fine in WordPress' config.php.

How do I center an SVG in a div?

I had to use

display: inline-block;

Importing Excel into a DataTable Quickly

In case anyone else is using EPPlus. This implementation is pretty naive, but there are comments that draw attention to such. If you were to layer one more method GetWorkbookAsDataSet() on top it would do what the OP is asking for.

    /// <summary>
    /// Assumption: Worksheet is in table format with no weird padding or blank column headers.
    /// 
    /// Assertion: Duplicate column names will be aliased by appending a sequence number (eg. Column, Column1, Column2)
    /// </summary>
    /// <param name="worksheet"></param>
    /// <returns></returns>
    public static DataTable GetWorksheetAsDataTable(ExcelWorksheet worksheet)
    {
        var dt = new DataTable(worksheet.Name);
        dt.Columns.AddRange(GetDataColumns(worksheet).ToArray());
        var headerOffset = 1; //have to skip header row
        var width = dt.Columns.Count;
        var depth = GetTableDepth(worksheet, headerOffset);
        for (var i = 1; i <= depth; i++)
        {
            var row = dt.NewRow();
            for (var j = 1; j <= width; j++)
            {
                var currentValue = worksheet.Cells[i + headerOffset, j].Value;

                //have to decrement b/c excel is 1 based and datatable is 0 based.
                row[j - 1] = currentValue == null ? null : currentValue.ToString();
            }

            dt.Rows.Add(row);
        }

        return dt;
    }

    /// <summary>
    /// Assumption: There are no null or empty cells in the first column
    /// </summary>
    /// <param name="worksheet"></param>
    /// <returns></returns>
    private static int GetTableDepth(ExcelWorksheet worksheet, int headerOffset)
    {
        var i = 1;
        var j = 1;
        var cellValue = worksheet.Cells[i + headerOffset, j].Value;
        while (cellValue != null)
        {
            i++;
            cellValue = worksheet.Cells[i + headerOffset, j].Value;
        }

        return i - 1; //subtract one because we're going from rownumber (1 based) to depth (0 based)
    }

    private static IEnumerable<DataColumn> GetDataColumns(ExcelWorksheet worksheet)
    {
        return GatherColumnNames(worksheet).Select(x => new DataColumn(x));
    }

    private static IEnumerable<string> GatherColumnNames(ExcelWorksheet worksheet)
    {
        var columns = new List<string>();

        var i = 1;
        var j = 1;
        var columnName = worksheet.Cells[i, j].Value;
        while (columnName != null)
        {
            columns.Add(GetUniqueColumnName(columns, columnName.ToString()));
            j++;
            columnName = worksheet.Cells[i, j].Value;
        }

        return columns;
    }

    private static string GetUniqueColumnName(IEnumerable<string> columnNames, string columnName)
    {
        var colName = columnName;
        var i = 1;
        while (columnNames.Contains(colName))
        {
            colName = columnName + i.ToString();
            i++;
        }

        return colName;
    }

How to set max width of an image in CSS

Given your container width 600px.

If you want only bigger images than that to fit inside, add: CSS:

#ImageContainer img {
    max-width: 600px;
}

If you want ALL images to take the avaiable (600px) space:

#ImageContainer img {
    width: 600px;
}

C# Convert a Base64 -> byte[]

You're looking for the FromBase64Transform class, used with the CryptoStream class.

If you have a string, you can also call Convert.FromBase64String.

How should I copy Strings in Java?

String str1="this is a string";
String str2=str1.clone();

How about copy like this? I think to get a new copy is better, so that the data of str1 won't be affected when str2 is reference and modified in futher action.

How to capture a JFrame's close button click event?

This is what I put as a menu option where I made a button on a JFrame to display another JFrame. I wanted only the new frame to be visible, and not to destroy the one behind it. I initially hid the first JFrame, while the new one became visible. Upon closing of the new JFrame, I disposed of it followed by an action of making the old one visible again.

Note: The following code expands off of Ravinda's answer and ng is a JButton:

ng.addActionListener((ActionEvent e) -> {
    setVisible(false);
    JFrame j = new JFrame("NAME");
    j.setVisible(true);
    j.addWindowListener(new java.awt.event.WindowAdapter() {
        @Override
        public void windowClosing(java.awt.event.WindowEvent windowEvent) {
            setVisible(true);
        }
    });
});

How do you specify a different port number in SQL Management Studio?

You'll need the SQL Server Configuration Manager. Go to Sql Native Client Configuration, Select Client Protocols, Right Click on TCP/IP and set your default port there.

Javascript negative number

How about something as simple as:

function negative(number){
    return number < 0;
}

The * 1 part is to convert strings to numbers.

What is the use of ObservableCollection in .net?

From Pro C# 5.0 and the .NET 4.5 Framework

The ObservableCollection<T> class is very useful in that it has the ability to inform external objects when its contents have changed in some way (as you might guess, working with ReadOnlyObservableCollection<T> is very similar, but read-only in nature). In many ways, working with the ObservableCollection<T> is identical to working with List<T>, given that both of these classes implement the same core interfaces. What makes the ObservableCollection<T> class unique is that this class supports an event named CollectionChanged. This event will fire whenever a new item is inserted, a current item is removed (or relocated), or if the entire collection is modified. Like any event, CollectionChanged is defined in terms of a delegate, which in this case is NotifyCollectionChangedEventHandler. This delegate can call any method that takes an object as the first parameter, and a NotifyCollectionChangedEventArgs as the second. Consider the following Main() method, which populates an observable collection containing Person objects and wires up the CollectionChanged event:

class Program
{
   static void Main(string[] args)
   {
     // Make a collection to observe and add a few Person objects.
     ObservableCollection<Person> people = new ObservableCollection<Person>()
     {
        new Person{ FirstName = "Peter", LastName = "Murphy", Age = 52 },
        new Person{ FirstName = "Kevin", LastName = "Key", Age = 48 },
     };
     // Wire up the CollectionChanged event.
     people.CollectionChanged += people_CollectionChanged;
     // Now add a new item.
     people.Add(new Person("Fred", "Smith", 32));

     // Remove an item.
     people.RemoveAt(0);

     Console.ReadLine();
   }
   static void people_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
   {
       // What was the action that caused the event?
        Console.WriteLine("Action for this event: {0}", e.Action);

        // They removed something. 
        if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
        {
            Console.WriteLine("Here are the OLD items:");
            foreach (Person p in e.OldItems)
            {
                Console.WriteLine(p.ToString());
            }
            Console.WriteLine();
        }

        // They added something. 
        if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
        {
            // Now show the NEW items that were inserted.
            Console.WriteLine("Here are the NEW items:");
            foreach (Person p in e.NewItems)
            {
                Console.WriteLine(p.ToString());
            }
        }
   }
}

The incoming NotifyCollectionChangedEventArgs parameter defines two important properties, OldItems and NewItems, which will give you a list of items that were currently in the collection before the event fired, and the new items that were involved in the change. However, you will want to examine these lists only under the correct circumstances. Recall that the CollectionChanged event can fire when items are added, removed, relocated, or reset. To discover which of these actions triggered the event, you can use the Action property of NotifyCollectionChangedEventArgs. The Action property can be tested against any of the following members of the NotifyCollectionChangedAction enumeration:

public enum NotifyCollectionChangedAction
{
Add = 0,
Remove = 1,
Replace = 2,
Move = 3,
Reset = 4,
}

Members of System.Collections.ObjectModel

Skip the headers when editing a csv file using Python

Inspired by Martijn Pieters' response.

In case you only need to delete the header from the csv file, you can work more efficiently if you write using the standard Python file I/O library, avoiding writing with the CSV Python library:

with open("tmob_notcleaned.csv", "rb") as infile, open("tmob_cleaned.csv", "wb") as outfile:
   next(infile)  # skip the headers
   outfile.write(infile.read())

Make div 100% Width of Browser Window

There are new units that you can use:

vw - viewport width

vh - viewport height

#neo_main_container1
{
   width: 100%; //fallback
   width: 100vw;
}

Help / MDN

Opera Mini does not support this, but you can use it in all other modern browsers.

CanIUse

enter image description here

Python SQLite: database is locked

I had this problem while working with Pycharm and with a database that was originally given to me by another user.

So, this is how I solve it in my case:

  1. Closed all tabs in Pycharm that operate with the problematic database.
  2. Stop all running processes from the red square botton in the top right corner of Pycharm.
  3. Delete the problematic database from the directory.
  4. Upload again the original database. And it worked again.

Angular2 handling http response

Update alpha 47

As of alpha 47 the below answer (for alpha46 and below) is not longer required. Now the Http module handles automatically the errores returned. So now is as easy as follows

http
  .get('Some Url')
  .map(res => res.json())
  .subscribe(
    (data) => this.data = data,
    (err) => this.error = err); // Reach here if fails

Alpha 46 and below

You can handle the response in the map(...), before the subscribe.

http
  .get('Some Url')
  .map(res => {
    // If request fails, throw an Error that will be caught
    if(res.status < 200 || res.status >= 300) {
      throw new Error('This request has failed ' + res.status);
    } 
    // If everything went fine, return the response
    else {
      return res.json();
    }
  })
  .subscribe(
    (data) => this.data = data, // Reach here if res.status >= 200 && <= 299
    (err) => this.error = err); // Reach here if fails

Here's a plnkr with a simple example.

Note that in the next release this won't be necessary because all status codes below 200 and above 299 will throw an error automatically, so you won't have to check them by yourself. Check this commit for more info.

How to split the screen with two equal LinearLayouts?

Just putting it out there:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FF0000"
    android:weightSum="4"
    android:padding="5dp"> <!-- to show what the parent is -->
    <LinearLayout
        android:background="#0000FF"
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="2" />
    <LinearLayout
        android:background="#00FF00"
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="1" />
</LinearLayout>

Creating a textarea with auto-resize

This works for me (Firefox 3.6/4.0 and Chrome 10/11):

_x000D_
_x000D_
var observe;_x000D_
if (window.attachEvent) {_x000D_
    observe = function (element, event, handler) {_x000D_
        element.attachEvent('on'+event, handler);_x000D_
    };_x000D_
}_x000D_
else {_x000D_
    observe = function (element, event, handler) {_x000D_
        element.addEventListener(event, handler, false);_x000D_
    };_x000D_
}_x000D_
function init () {_x000D_
    var text = document.getElementById('text');_x000D_
    function resize () {_x000D_
        text.style.height = 'auto';_x000D_
        text.style.height = text.scrollHeight+'px';_x000D_
    }_x000D_
    /* 0-timeout to get the already changed text */_x000D_
    function delayedResize () {_x000D_
        window.setTimeout(resize, 0);_x000D_
    }_x000D_
    observe(text, 'change',  resize);_x000D_
    observe(text, 'cut',     delayedResize);_x000D_
    observe(text, 'paste',   delayedResize);_x000D_
    observe(text, 'drop',    delayedResize);_x000D_
    observe(text, 'keydown', delayedResize);_x000D_
_x000D_
    text.focus();_x000D_
    text.select();_x000D_
    resize();_x000D_
}
_x000D_
textarea {_x000D_
    border: 0 none white;_x000D_
    overflow: hidden;_x000D_
    padding: 0;_x000D_
    outline: none;_x000D_
    background-color: #D0D0D0;_x000D_
}
_x000D_
<body onload="init();">_x000D_
<textarea rows="1" style="height:1em;" id="text"></textarea>_x000D_
</body>
_x000D_
_x000D_
_x000D_

If you want try it on jsfiddle It starts with a single line and grows only the exact amount necessary. It is ok for a single textarea, but I wanted to write something where I would have many many many such textareas (about as much as one would normally have lines in a large text document). In that case it is really slow. (In Firefox it's insanely slow.) So I really would like an approach that uses pure CSS. This would be possible with contenteditable, but I want it to be plaintext-only.

Difference between VARCHAR2(10 CHAR) and NVARCHAR2(10)

The NVARCHAR2 datatype was introduced by Oracle for databases that want to use Unicode for some columns while keeping another character set for the rest of the database (which uses VARCHAR2). The NVARCHAR2 is a Unicode-only datatype.

One reason you may want to use NVARCHAR2 might be that your DB uses a non-Unicode character set and you still want to be able to store Unicode data for some columns without changing the primary character set. Another reason might be that you want to use two Unicode character set (AL32UTF8 for data that comes mostly from western Europe, AL16UTF16 for data that comes mostly from Asia for example) because different character sets won't store the same data equally efficiently.

Both columns in your example (Unicode VARCHAR2(10 CHAR) and NVARCHAR2(10)) would be able to store the same data, however the byte storage will be different. Some strings may be stored more efficiently in one or the other.

Note also that some features won't work with NVARCHAR2, see this SO question:

How can I adjust DIV width to contents

One way you can achieve this is setting display: inline-block; on the div. It is by default a block element, which will always fill the width it can fill (unless specifying width of course).

inline-block's only downside is that IE only supports it correctly from version 8. IE 6-7 only allows setting it on naturally inline elements, but there are hacks to solve this problem.

There are other options you have, you can either float it, or set position: absolute on it, but these also have other effects on layout, you need to decide which one fits your situation better.

Order data frame rows according to vector with specific order

This method is a bit different, it provided me with a bit more flexibility than the previous answer. By making it into an ordered factor, you can use it nicely in arrange and such. I used reorder.factor from the gdata package.

df <- data.frame(name=letters[1:4], value=c(rep(TRUE, 2), rep(FALSE, 2)))
target <- c("b", "c", "a", "d")

require(gdata)
df$name <- reorder.factor(df$name, new.order=target)

Next, use the fact that it is now ordered:

require(dplyr)
df %>%
  arrange(name)
    name value
1    b  TRUE
2    c FALSE
3    a  TRUE
4    d FALSE

If you want to go back to the original (alphabetic) ordering, just use as.character() to get it back to the original state.

Callback to a Fragment from a DialogFragment

Activity involved is completely unaware of the DialogFragment.

Fragment class:

public class MyFragment extends Fragment {
int mStackLevel = 0;
public static final int DIALOG_FRAGMENT = 1;

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

    if (savedInstanceState != null) {
        mStackLevel = savedInstanceState.getInt("level");
    }
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putInt("level", mStackLevel);
}

void showDialog(int type) {

    mStackLevel++;

    FragmentTransaction ft = getActivity().getFragmentManager().beginTransaction();
    Fragment prev = getActivity().getFragmentManager().findFragmentByTag("dialog");
    if (prev != null) {
        ft.remove(prev);
    }
    ft.addToBackStack(null);

    switch (type) {

        case DIALOG_FRAGMENT:

            DialogFragment dialogFrag = MyDialogFragment.newInstance(123);
            dialogFrag.setTargetFragment(this, DIALOG_FRAGMENT);
            dialogFrag.show(getFragmentManager().beginTransaction(), "dialog");

            break;
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch(requestCode) {
            case DIALOG_FRAGMENT:

                if (resultCode == Activity.RESULT_OK) {
                    // After Ok code.
                } else if (resultCode == Activity.RESULT_CANCELED){
                    // After Cancel code.
                }

                break;
        }
    }
}

}

DialogFragment class:

public class MyDialogFragment extends DialogFragment {

public static MyDialogFragment newInstance(int num){

    MyDialogFragment dialogFragment = new MyDialogFragment();
    Bundle bundle = new Bundle();
    bundle.putInt("num", num);
    dialogFragment.setArguments(bundle);

    return dialogFragment;

}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {

    return new AlertDialog.Builder(getActivity())
            .setTitle(R.string.ERROR)
            .setIcon(android.R.drawable.ic_dialog_alert)
            .setPositiveButton(R.string.ok_button,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int whichButton) {
                            getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, getActivity().getIntent());
                        }
                    }
            )
            .setNegativeButton(R.string.cancel_button, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int whichButton) {
                    getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_CANCELED, getActivity().getIntent());
                }
            })
            .create();
}
}

Detect Browser Language in PHP

Unfortunately, none of the answers to this question takes into account some valid HTTP_ACCEPT_LANGUAGE such as:

  • q=0.8,en-US;q=0.5,en;q=0.3: having the q priority value at first place.
  • ZH-CN: old browsers that capitalise (wrongly) the whole langcode.
  • *: that basically say "serve whatever language you have".

After a comprehensive test with thousands of different Accept-Languages in my server, I ended up having this language detection method:

define('SUPPORTED_LANGUAGES', ['en', 'es']);

function detect_language() {
    foreach (preg_split('/[;,]/', $_SERVER['HTTP_ACCEPT_LANGUAGE']) as $sub) {
        if (substr($sub, 0, 2) == 'q=') continue;
        if (strpos($sub, '-') !== false) $sub = explode('-', $sub)[0];
        if (in_array(strtolower($sub), SUPPORTED_LANGUAGES)) return $sub;
    }
    return 'en';
}

Declaring and using MySQL varchar variables

This works fine for me using MySQL 5.1.35:

DELIMITER $$

DROP PROCEDURE IF EXISTS `example`.`test` $$
CREATE PROCEDURE `example`.`test` ()
BEGIN

  DECLARE FOO varchar(7);
  DECLARE oldFOO varchar(7);
  SET FOO = '138';
  SET oldFOO = CONCAT('0', FOO);

  update mypermits
     set person = FOO
   where person = oldFOO;

END $$

DELIMITER ;

Table:

DROP TABLE IF EXISTS `example`.`mypermits`;
CREATE TABLE  `example`.`mypermits` (
  `person` varchar(7) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO mypermits VALUES ('0138');

CALL test()

How can I lookup a Java enum from its String value?

@Lyle's answer is rather dangerous and I have seen it not work particularly if you make the enum a static inner class. Instead I have used something like this which will load the BootstrapSingleton maps before the enums.

Edit this should not be a problem any more with modern JVMs (JVM 1.6 or greater) but I do think there are still issues with JRebel but I haven't had a chance to retest it.

Load me first:

   public final class BootstrapSingleton {

        // Reverse-lookup map for getting a day from an abbreviation
        public static final Map<String, Day> lookup = new HashMap<String, Day>();
   }

Now load it in the enum constructor:

   public enum Day { 
        MONDAY("M"), TUESDAY("T"), WEDNESDAY("W"),
        THURSDAY("R"), FRIDAY("F"), SATURDAY("Sa"), SUNDAY("Su"), ;

        private final String abbreviation;

        private Day(String abbreviation) {
            this.abbreviation = abbreviation;
            BootstrapSingleton.lookup.put(abbreviation, this);
        }

        public String getAbbreviation() {
            return abbreviation;
        }

        public static Day get(String abbreviation) {
            return lookup.get(abbreviation);
        }
    }

If you have an inner enum you can just define the Map above the enum definition and that (in theory) should get loaded before.

How to refresh table contents in div using jquery/ajax

You can load HTML page partial, in your case is everything inside div#mytable.

setTimeout(function(){
   $( "#mytable" ).load( "your-current-page.html #mytable" );
}, 2000); //refresh every 2 seconds

more information read this http://api.jquery.com/load/

Update Code (if you don't want it auto-refresh)

<button id="refresh-btn">Refresh Table</button>

<script>
$(document).ready(function() {

   function RefreshTable() {
       $( "#mytable" ).load( "your-current-page.html #mytable" );
   }

   $("#refresh-btn").on("click", RefreshTable);

   // OR CAN THIS WAY
   //
   // $("#refresh-btn").on("click", function() {
   //    $( "#mytable" ).load( "your-current-page.html #mytable" );
   // });


});
</script>

What is the difference between POST and GET?

A POST, unlike a GET, typically has relevant information in the body of the request. (A GET should not have a body, so aside from cookies, the only place to pass info is in the URL.) Besides keeping the URL relatively cleaner, POST also lets you send much more information (as URLs are limited in length, for all practical purposes), and lets you send just about any type of data (file upload forms, for example, can't use GET -- they have to use POST plus a special content type/encoding).

Aside from that, a POST connotes that the request will change something, and shouldn't be redone willy-nilly. That's why you sometimes see your browser asking you if you want to resubmit form data when you hit the "back" button.

GET, on the other hand, should be idempotent -- meaning you could do it a million times and the server will do the same thing (and show basically the same result) each and every time.

Installing jQuery?

There is none. Use script tags to link to google's version (or download it yourself and link to your copy if you really want to).

If you don't know how to do that, learn HTML and Javascript first before attempting to learn jQuery.

Ajax - 500 Internal Server Error

The 500 (internal server error) means something went wrong on the server's side. It could be several things, but I would start by verifying that the URL and parameters are correct. Also, make sure that whatever handles the request is expecting the request as a GET and not a POST.

One useful way to learn more about what's going on is to use a tool like Fiddler which will let you watch all HTTP requests and responses so you can see exactly what you're sending and the server is responding with.

If you don't have a compelling reason to write your own Ajax code, you would be far better off using a library that handles the Ajax interactions for you. jQuery is one option.

Tooltips with Twitter Bootstrap

Simple use of this:

<a href="#" id="mytooltip" class="btn btn-praimary" data-toggle="tooltip" title="my tooltip">
   tooltip
</a>

Using jQuery:

$(document).ready(function(){
    $('#mytooltip').tooltip();
});

You can left side of tooltip u can simple add this->data-placement="left"

<a href="#" id="mytooltip" class="btn btn-praimary" data-toggle="tooltip" title="my tooltip" data-placement="left">tooltip</a>

What's the best practice to round a float to 2 decimals?

I was working with statistics in Java 2 years ago and I still got the codes of a function that allows you to round a number to the number of decimals that you want. Now you need two, but maybe you would like to try with 3 to compare results, and this function gives you this freedom.

/**
* Round to certain number of decimals
* 
* @param d
* @param decimalPlace
* @return
*/
public static float round(float d, int decimalPlace) {
    BigDecimal bd = new BigDecimal(Float.toString(d));
    bd = bd.setScale(decimalPlace, BigDecimal.ROUND_HALF_UP);
    return bd.floatValue();
}

You need to decide if you want to round up or down. In my sample code I am rounding up.

Hope it helps.

EDIT

If you want to preserve the number of decimals when they are zero (I guess it is just for displaying to the user) you just have to change the function type from float to BigDecimal, like this:

public static BigDecimal round(float d, int decimalPlace) {
    BigDecimal bd = new BigDecimal(Float.toString(d));
    bd = bd.setScale(decimalPlace, BigDecimal.ROUND_HALF_UP);       
    return bd;
}

And then call the function this way:

float x = 2.3f;
BigDecimal result;
result=round(x,2);
System.out.println(result);

This will print:

2.30

I have Python on my Ubuntu system, but gcc can't find Python.h

locate Python.h

If the output is empty, then find your python version

python --version

lets say it is X.x i.e 2.7 or 3.6, 3.7, 3.8 Then with the same version install header files and static libraries for python

sudo apt-get install pythonX.x-dev

Is there a way to create multiline comments in Python?

AFAIK, Python doesn't have block comments. For commenting individual lines, you can use the # character.

If you are using Notepad++, there is a shortcut for block commenting. I'm sure others like gVim and Emacs have similar features.

How to convert a Collection to List?

I believe you can write it as such:

coll.stream().collect(Collectors.toList())

How do I disable a Pylint warning?

As per Pylint documentation, the easiest is to use this chart:

  • C convention-related checks
  • R refactoring-related checks
  • W various warnings
  • E errors, for probable bugs in the code
  • F fatal, if an error occurred which prevented Pylint from doing further processing.

So one can use:

pylint -j 0 --disable=I,E,R,W,C,F YOUR_FILES_LOC

How to capture a backspace on the onkeydown event

Try this:

document.addEventListener("keydown", KeyCheck);  //or however you are calling your method
function KeyCheck(event)
{
   var KeyID = event.keyCode;
   switch(KeyID)
   {
      case 8:
      alert("backspace");
      break; 
      case 46:
      alert("delete");
      break;
      default:
      break;
   }
}

Declare variable in table valued function

There are two flavors of table valued functions. One that is just a select statement and one that can have more rows than just a select statement.

This can not have a variable:

create function Func() returns table
as
return
select 10 as ColName

You have to do like this instead:

create function Func()
returns @T table(ColName int)
as
begin
  declare @Var int
  set @Var = 10
  insert into @T(ColName) values (@Var)
  return
end

Subset of rows containing NA (missing) values in a chosen column of a data frame

NA is a special value in R, do not mix up the NA value with the "NA" string. Depending on the way the data was imported, your "NA" and "NULL" cells may be of various type (the default behavior is to convert "NA" strings to NA values, and let "NULL" strings as is).

If using read.table() or read.csv(), you should consider the "na.strings" argument to do clean data import, and always work with real R NA values.

An example, working in both cases "NULL" and "NA" cells :

DF <- read.csv("file.csv", na.strings=c("NA", "NULL"))
new_DF <- subset(DF, is.na(DF$Var2))

How to find NSDocumentDirectory in Swift?

Apparently, the compiler thinks NSSearchPathDirectory:0 is an array, and of course it expects the type NSSearchPathDirectory instead. Certainly not a helpful error message.

But as to the reasons:

First, you are confusing the argument names and types. Take a look at the function definition:

func NSSearchPathForDirectoriesInDomains(
    directory: NSSearchPathDirectory,
    domainMask: NSSearchPathDomainMask,
    expandTilde: Bool) -> AnyObject[]!
  • directory and domainMask are the names, you are using the types, but you should leave them out for functions anyway. They are used primarily in methods.
  • Also, Swift is strongly typed, so you shouldn't just use 0. Use the enum's value instead.
  • And finally, it returns an array, not just a single path.

So that leaves us with (updated for Swift 2.0):

let documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0]

and for Swift 3:

let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]

Visual c++ can't open include file 'iostream'

In my case, my VS2015 installed without select C++ package, and VS2017 is installed with C++ package. If I use VS2015 open C++ project will show this error, and using VS2017 will be no error.

how to re-format datetime string in php?

https://en.functions-online.com/date.html?command={"format":"l jS \\of F Y h:i:s A"}

Quickly create a large file on a Linux system

One approach: if you can guarantee unrelated applications won't use the files in a conflicting manner, just create a pool of files of varying sizes in a specific directory, then create links to them when needed.

For example, have a pool of files called:

  • /home/bigfiles/512M-A
  • /home/bigfiles/512M-B
  • /home/bigfiles/1024M-A
  • /home/bigfiles/1024M-B

Then, if you have an application that needs a 1G file called /home/oracle/logfile, execute a "ln /home/bigfiles/1024M-A /home/oracle/logfile".

If it's on a separate filesystem, you will have to use a symbolic link.

The A/B/etc files can be used to ensure there's no conflicting use between unrelated applications.

The link operation is about as fast as you can get.

Android: how to parse URL String with spaces to URI object?

I wrote this function:

public static String encode(@NonNull String uriString) {
    if (TextUtils.isEmpty(uriString)) {
        Assert.fail("Uri string cannot be empty!");
        return uriString;
    }
    // getQueryParameterNames is not exist then cannot iterate on queries
    if (Build.VERSION.SDK_INT < 11) {
        return uriString;
    }

    // Check if uri has valid characters
    // See https://tools.ietf.org/html/rfc3986
    Pattern allowedUrlCharacters = Pattern.compile("([A-Za-z0-9_.~:/?\\#\\[\\]@!$&'()*+,;" +
            "=-]|%[0-9a-fA-F]{2})+");
    Matcher matcher = allowedUrlCharacters.matcher(uriString);
    String validUri = null;
    if (matcher.find()) {
        validUri = matcher.group();
    }
    if (TextUtils.isEmpty(validUri) || uriString.length() == validUri.length()) {
        return uriString;
    }

    // The uriString is not encoded. Then recreate the uri and encode it this time
    Uri uri = Uri.parse(uriString);
    Uri.Builder uriBuilder = new Uri.Builder()
            .scheme(uri.getScheme())
            .authority(uri.getAuthority());
    for (String path : uri.getPathSegments()) {
        uriBuilder.appendPath(path);
    }
    for (String key : uri.getQueryParameterNames()) {
        uriBuilder.appendQueryParameter(key, uri.getQueryParameter(key));
    }
    String correctUrl = uriBuilder.build().toString();
    return correctUrl;
}

Using ADB to capture the screen

To save to a file on Windows, OSX and Linux

adb exec-out screencap -p > screen.png

To copy to clipboard on Linux use

adb exec-out screencap -p | xclip -t image/png

Redirect to external URI from ASP.NET MVC controller

Try this (I've used Home controller and Index View):

return RedirectToAction("Index", "Home");

Free ASP.Net and/or CSS Themes

I wouldn't bother looking for ASP.NET stuff specifically (probably won't find any anyways). Finding a good CSS theme easily can be used in ASP.NET.

Here's some sites that I love for CSS goodness:

http://www.freecsstemplates.org/
http://www.oswd.org/
http://www.openwebdesign.org/
http://www.styleshout.com/
http://www.freelayouts.com/

How do I assert equality on two classes without an equals method?

I stumbled on a very similar case.

I wanted to compare on a test that an object had the same attribute values as another one, but methods like is(), refEq(), etc wouldn't work for reasons like my object having a null value in its id attribute.

So this was the solution I found (well, a coworker found):

import static org.apache.commons.lang.builder.CompareToBuilder.reflectionCompare;

assertThat(reflectionCompare(expectedObject, actualObject, new String[]{"fields","to","be","excluded"}), is(0));

If the value obtained from reflectionCompare is 0, it means they are equal. If it is -1 or 1, they differ on some attribute.

Check if a string matches a regex in Bash script

In bash version 3 you can use the '=~' operator:

if [[ "$date" =~ ^[0-9]{8}$ ]]; then
    echo "Valid date"
else
    echo "Invalid date"
fi

Reference: http://tldp.org/LDP/abs/html/bashver3.html#REGEXMATCHREF

NOTE: The quoting in the matching operator within the double brackets, [[ ]], is no longer necessary as of Bash version 3.2

Put byte array to JSON and vice versa

The typical way to send binary in json is to base64 encode it.

Java provides different ways to Base64 encode and decode a byte[]. One of these is DatatypeConverter.

Very simply

byte[] originalBytes = new byte[] { 1, 2, 3, 4, 5};
String base64Encoded = DatatypeConverter.printBase64Binary(originalBytes);
byte[] base64Decoded = DatatypeConverter.parseBase64Binary(base64Encoded);

You'll have to make this conversion depending on the json parser/generator library you use.

Get a random boolean in python?

I was curious as to how the speed of the numpy answer performed against the other answers since this was left out of the comparisons. To generate one random bool this is much slower but if you wanted to generate many then this becomes much faster:

$ python -m timeit -s "from random import random" "random() < 0.5"
10000000 loops, best of 3: 0.0906 usec per loop
$ python -m timeit -s "import numpy as np" "np.random.randint(2, size=1)"
100000 loops, best of 3: 4.65 usec per loop

$ python -m timeit -s "from random import random" "test = [random() < 0.5 for i in range(1000000)]"
10 loops, best of 3: 118 msec per loop
$ python -m timeit -s "import numpy as np" "test = np.random.randint(2, size=1000000)"
100 loops, best of 3: 6.31 msec per loop

How to return a class object by reference in C++?

You can only return non-local objects by reference. The destructor may have invalidated some internal pointer, or whatever.

Don't be afraid of returning values -- it's fast!

Angular 5 Button Submit On Enter Key Press

try use keyup.enter or keydown.enter

  <button type="submit" (keyup.enter)="search(...)">Search</button>

Java Class.cast() vs. cast operator

Generally the cast operator is preferred to the Class#cast method as it's more concise and can be analyzed by the compiler to spit out blatant issues with the code.

Class#cast takes responsibility for type checking at run-time rather than during compilation.

There are certainly use-cases for Class#cast, particularly when it comes to reflective operations.

Since lambda's came to java I personally like using Class#cast with the collections/stream API if I'm working with abstract types, for example.

Dog findMyDog(String name, Breed breed) {
    return lostAnimals.stream()
                      .filter(Dog.class::isInstance)
                      .map(Dog.class::cast)
                      .filter(dog -> dog.getName().equalsIgnoreCase(name))
                      .filter(dog -> dog.getBreed() == breed)
                      .findFirst()
                      .orElse(null);
}

How do I avoid the specification of the username and password at every git push?

If your PC is secure or you don't care about password security, this can be achieved very simply. Assuming that the remote repository is on GitHub and origin is your local name for the remote repository, use this command

git remote set-url --push origin https://<username>:<password>@github.com/<repo>

The --push flag ensures this changes the URL of the repository for the git push command only. (The question asked in the original post is about git push command only. Requiring a username+password only for push operations is the normal setup for public repositories on GitHub . Note that private repositories on GitHub would also require a username+password for pull and fetch operations, so for a private repository you would not want to use the --push flag ...)

WARNING: This is inherently unsecure because:

  1. your ISP, or anyone logging your network accesses, can easily see the password in plain text in the URL;

  2. anyone who gains access to your PC can view your password using git remote show origin.

That's why using an SSH key is the accepted answer.

Even an SSH key is not totally secure. Anyone who gains access to your PC can still, for example, make pushes which wreck your repository or - worse - push commits making subtle changes to your code. (All pushed commits are obviously highly visible on GitHub. But if someone wanted to change your code surreptitiously, they could --amend a previous commit without changing the commit message, and then force push it. That would be stealthy and quite hard to notice in practice.)

But revealing your password is worse. If an attacker gains knowledge of your username+password, they can do things like lock you out of your own account, delete your account, permanently delete the repository, etc.


Alternatively - for simplicity and security - you can supply only your username in the URL, so that you will have to type your password every time you git push but you will not have to give your username each time. (I quite like this approach, having to type the password gives me a pause to think each time I git push, so I cannot git push by accident.)

git remote set-url --push origin https://<username>@github.com/<repo>

Skip Git commit hooks

Maybe (from git commit man page):

git commit --no-verify

-n  
--no-verify

This option bypasses the pre-commit and commit-msg hooks. See also githooks(5).

As commented by Blaise, -n can have a different role for certain commands.
For instance, git push -n is actually a dry-run push.
Only git push --no-verify would skip the hook.


Note: Git 2.14.x/2.15 improves the --no-verify behavior:

See commit 680ee55 (14 Aug 2017) by Kevin Willford (``).
(Merged by Junio C Hamano -- gitster -- in commit c3e034f, 23 Aug 2017)

commit: skip discarding the index if there is no pre-commit hook

"git commit" used to discard the index and re-read from the filesystem just in case the pre-commit hook has updated it in the middle; this has been optimized out when we know we do not run the pre-commit hook.


Davi Lima points out in the comments the git cherry-pick does not support --no-verify.
So if a cherry-pick triggers a pre-commit hook, you might, as in this blog post, have to comment/disable somehow that hook in order for your git cherry-pick to proceed.
The same process would be necessary in case of a git rebase --continue, after a merge conflict resolution.

Writing your own square root function

Let me point out an extremely interesting method of calculating an inverse square root 1/sqrt(x) which is a legend in the world of game design because it is mind-boggingly fast. Or wait, read the following post:

http://betterexplained.com/articles/understanding-quakes-fast-inverse-square-root/

PS: I know you just want the square root but the elegance of quake overcame all resistance on my part :)

By the way, the above mentioned article also talks about the boring Newton-Raphson approximation somewhere.

REST URI convention - Singular or plural name of resource while creating it

See Google's API Design Guide: Resource Names for another take on naming resources.

The guide requires collections to be named with plurals.

|--------------------------+---------------+-------------------+---------------+--------------|
| API Service Name         | Collection ID | Resource ID       | Collection ID | Resource ID  |
|--------------------------+---------------+-------------------+---------------+--------------|
| //mail.googleapis.com    | /users        | /[email protected] | /settings     | /customFrom  |
| //storage.googleapis.com | /buckets      | /bucket-id        | /objects      | /object-id   |
|--------------------------+---------------+-------------------+---------------+--------------|

It's worthwhile reading if you're thinking about this subject.

How to host a Node.Js application in shared hosting

You should look for a hosting company that provides such feature, but standard simple static+PHP+MySQL hosting won't let you use node.js.

You need either find a hosting designed for node.js or buy a Virtual Private Server and install it yourself.

How to Generate unique file names in C#

Use

Path.GetTempFileName()

or use new GUID().

Path.GetTempFilename() on MSDN.

implements Closeable or implements AutoCloseable

Recently I have read a Java SE 8 Programmer Guide ii Book.

I found something about the difference between AutoCloseable vs Closeable.

The AutoCloseable interface was introduced in Java 7. Before that, another interface existed called Closeable. It was similar to what the language designers wanted, with the following exceptions:

  • Closeable restricts the type of exception thrown to IOException.
  • Closeable requires implementations to be idempotent.

The language designers emphasize backward compatibility. Since changing the existing interface was undesirable, they made a new one called AutoCloseable. This new interface is less strict than Closeable. Since Closeable meets the requirements for AutoCloseable, it started implementing AutoCloseable when the latter was introduced.

Getting JSONObject from JSONArray

Here is your json:

{
    "syncresponse": {
       "synckey": "2011-09-30 14:52:00",
        "createdtrs": [

        ],
        "modtrs": [

        ],
        "deletedtrs": [
          {
           "companyid": "UTB17",
           "username": "DA",
           "date": "2011-09-26",
           "reportid": "31341"
      }
       ]
   }
}

and it's parsing:

JSONObject object = new JSONObject(result);
String syncresponse = object.getString("syncresponse");
JSONObject object2 = new JSONObject(syncresponse);
String synckey = object2.getString("synckey");
JSONArray jArray1 = object2.getJSONArray("createdtrs");
JSONArray jArray2 = object2.getJSONArray("modtrs");
JSONArray jArray3 = object2.getJSONArray("deletedtrs");
for(int i = 0; i < jArray3 .length(); i++)
{
   JSONObject object3 = jArray3.getJSONObject(i);
   String comp_id = object3.getString("companyid");
   String username = object3.getString("username");
   String date = object3.getString("date");
   String report_id = object3.getString("reportid");
}

Select2 open dropdown on focus

Probably after the selection is made a select2-focus event is triggered.

The only way I found is a combination of select2-focus and select2-blur event and the jQuery one event handler.

So the first time the element get the focus, the select2 is opened for one time (because of one), when the element is blurred the one event handler is attached again and so on.

Code:

$('#test').select2({
    data: [{
        id: 0,
        text: "enhancement"
    }, {
        id: 1,
        text: "bug"
    }, {
        id: 2,
        text: "duplicate"
    }, {
        id: 3,
        text: "invalid"
    }, {
        id: 4,
        text: "wontfix"
    }],
    width: "300px"
}).one('select2-focus', select2Focus).on("select2-blur", function () {
    $(this).one('select2-focus', select2Focus)
})

function select2Focus() {
    $(this).select2('open');
}

Demo: http://jsfiddle.net/IrvinDominin/fnjNb/

UPDATE

To let the mouse click work you must check the event that fires the handler, it must fire the open method only if the event is focus

Code:

function select2Focus() {
    if (/^focus/.test(event.type)) {
        $(this).select2('open');
    }
}

Demo: http://jsfiddle.net/IrvinDominin/fnjNb/4/

UPDATE FOR SELECT2 V 4.0

select2 v 4.0 has changed its API's and dropped the custom events (see https://github.com/select2/select2/issues/1908). So it's necessary change the way to detect the focus on it.

Code:

$('.js-select').select2({
    placeholder: "Select",
    width: "100%"
})

$('.js-select').next('.select2').find('.select2-selection').one('focus', select2Focus).on('blur', function () {
    $(this).one('focus', select2Focus)
})

function select2Focus() {
    $(this).closest('.select2').prev('select').select2('open');
}

Demo: http://jsfiddle.net/IrvinDominin/xfmgte70/

How do I get my C# program to sleep for 50 msec?

For readability:

using System.Threading;
Thread.Sleep(TimeSpan.FromMilliseconds(50));

How To Use DateTimePicker In WPF?

This just came in ;)

There is a new DatePicker class for WPF in the .NET 4.0 runtime: http://msdn.microsoft.com/en-us/library/system.windows.controls.datepicker.aspx

Also see the "Whats new in WPF" for more nice features: http://msdn.microsoft.com/en-us/library/bb613588.aspx

How do I execute cmd commands through a batch file?

@echo off
title Command Executer
color 1b

echo Command Executer by: YourNameHere
echo #################################
: execute
echo Please Type A Command Here:
set /p cmd=Command:
%cmd%
goto execute

Using FileUtils in eclipse

Now selenium supports following code:

FileHandler.copy(src, dest);

CKEditor automatically strips classes from div

if you're using ckeditor 4.x you can try

config.allowedContent = true;

if you're using ckeditor 3.x you may be having this issue.

try putting the following line in config.js

config.ignoreEmptyParagraph = false;

What causes a TCP/IP reset (RST) flag to be sent?

Run a packet sniffer (e.g., Wireshark) also on the peer to see whether it's the peer who's sending the RST or someone in the middle.

Ignore Duplicates and Create New List of Unique Values in Excel

I have a list of color names in range A2:A8, in column B I want to extract a distinct list of color names.

Follow the below given steps:

  • Select the Cell B2; write the formula to retrieve the unique values from a list.
  • =IF(COUNTIF(A$2:A2,A2)=1,A2,””)
  • Press Enter on your keyboard.
  • The function will return the name of the first color.
  • To return the value for the rest of cells, copy the same formula down. To copy formula in range B3:B8, copy the formula in cell B2 by pressing the key CTRL+C on your keyboard and paste in the range B3:B8 by pressing the key CTRL+V.
  • Here you can see the output where we have the unique list of color names.

How to check if a process is running via a batch script

I used the script provided by Matt (2008-10-02). The only thing I had trouble with was that it wouldn't delete the search.log file. I expect because I had to cd to another location to start my program. I cd'd back to where the BAT file and search.log are, but it still wouldn't delete. So I resolved that by deleting the search.log file first instead of last.

del search.log

tasklist /FI "IMAGENAME eq myprog.exe" /FO CSV > search.log

FOR /F %%A IN (search.log) DO IF %%-zA EQU 0 GOTO end

cd "C:\Program Files\MyLoc\bin"

myprog.exe myuser mypwd

:end

How to link HTML5 form action to Controller ActionResult method in ASP.NET MVC 4

Here I'm basically wrapping a button in a link. The advantage is that you can post to different action methods in the same form.

<a href="Controller/ActionMethod">
    <input type="button" value="Click Me" />
</a>

Adding parameters:

<a href="Controller/ActionMethod?userName=ted">
    <input type="button" value="Click Me" />
</a>

Adding parameters from a non-enumerated Model:

<a href="Controller/[email protected]">
    <input type="button" value="Click Me" />
</a>

You can do the same for an enumerated Model too. You would just have to reference a single entity first. Happy Coding!

SQL state [99999]; error code [17004]; Invalid column type: 1111 With Spring SimpleJdbcCall

I had this problem, and turns out the problem was that I had used

new SimpleJdbcCall(jdbcTemplate)
    .withProcedureName("foo")

instead of

new SimpleJdbcCall(jdbcTemplate)
    .withFunctionName("foo")

Function return value in PowerShell

I pass around a simple Hashtable object with a single result member to avoid the return craziness as I also want to output to the console. It acts through pass by reference.

function sample-loop($returnObj) {
  for($i = 0; $i -lt 10; $i++) {
    Write-Host "loop counter: $i"
    $returnObj.result++
  }
}

function main-sample() {
  $countObj = @{ result = 0 }
  sample-loop -returnObj $countObj
  Write-Host "_____________"
  Write-Host "Total = " ($countObj.result)
}

main-sample

You can see real example usage at my GitHub project unpackTunes.

How to convert a string with Unicode encoding to a string of letters

Shorter version:

public static String unescapeJava(String escaped) {
    if(escaped.indexOf("\\u")==-1)
        return escaped;

    String processed="";

    int position=escaped.indexOf("\\u");
    while(position!=-1) {
        if(position!=0)
            processed+=escaped.substring(0,position);
        String token=escaped.substring(position+2,position+6);
        escaped=escaped.substring(position+6);
        processed+=(char)Integer.parseInt(token,16);
        position=escaped.indexOf("\\u");
    }
    processed+=escaped;

    return processed;
}

How can I programmatically invoke an onclick() event from a anchor tag while keeping the ‘this’ reference in the onclick function?

The best way to solve this is to use Vanilla JS, but if you are already using jQuery, there´s a very easy solution:

<script type="text/javascript">
    function doOnClick() {
        $('#linkid').click();
    }
</script>
<a id="linkid" href="/testlocation" onclick="alert(this.href);">Testlink</a>

Tested in IE8-10, Chrome, Firefox.

Check if image exists on server using JavaScript?

If you create an image tag and add it to the DOM, either its onload or onerror event should fire. If onerror fires, the image doesn't exist on the server.

Starting with Zend Tutorial - Zend_DB_Adapter throws Exception: "SQLSTATE[HY000] [2002] No such file or directory"

i had this problem when running the magento indexer in osx. and yes its related to php problem when connecting to mysql through pdo

in mac osx xampp, to fix this you have create symbolic link to directory /var/mysql, here is how

cd /var/mysql && sudo ln -s /Applications/XAMPP/xamppfiles/var/mysql/mysql.sock

if the directory /var/mysql doesnt exist, we must create it with

sudo mkdir /var/mysql

How to get a complete list of ticker symbols from Yahoo Finance?

I have been researching this for a few days, following endless leads that got close, but not quite, to what I was after.

My need is for a simple list of 'symbol, sector, industry'. I'm working in Java and don't want to use any platform native code.

It seems that most other data, like quotes, etc., is readily available.

Finally, followed a suggestion to look at 'finviz.com'. Looks like just the ticket. Try using the following:

http://finviz.com/export.ashx?v=111&t=aapl,cat&o=ticker This comes back as lines, csv style, with a header row, ordered by ticker symbol. You can keep adding tickers. In code, you can read the stream. Or you can let the browser ask you whether to open or save the file.

http://finviz.com/export.ashx?v=111&&o=ticker Same csv style, but pulls all available symbols (a lot, across global exchanges)

Replace 'export' with 'screener' and the data will show up in the browser.

There are many more options you can use, one for every screener element on the site.

So far, this is the most powerful and convenient programmatic way to get the few pieces of data I couldn't otherwise seem to easily get. And, it looks like this site could well be a single source for most of what you might need other than real- or near-real-time quotes.

Android Fastboot devices not returning device

Are you rebooting the device into the bootloader and entering fastboot USB on the bootloader menu?

Try

adb reboot bootloader

then look for on screen instructions to enter fastboot mode.

Vue component event after render

updated might be what you're looking for. https://vuejs.org/v2/api/#updated

MyISAM versus InnoDB

In my experience, MyISAM was a better choice as long as you don't do DELETEs, UPDATEs, a whole lot of single INSERT, transactions, and full-text indexing. BTW, CHECK TABLE is horrible. As the table gets older in terms of the number of rows, you don't know when it will end.

How to locate the git config file in Mac

I use this function which is saved in .bash_profile and it works a treat for me.

function show_hidden () {
        { defaults write com.apple.finder AppleShowAllFiles $1; killall -HUP Finder; }
}

How to use:

show_hidden true|false 

Sorting HashMap by values

public static TreeMap<String, String> sortMap(HashMap<String, String> passedMap, String byParam) {
    if(byParam.trim().toLowerCase().equalsIgnoreCase("byValue")) {
        // Altering the (key, value) -> (value, key)
        HashMap<String, String> newMap =  new HashMap<String, String>();
        for (Map.Entry<String, String> entry : passedMap.entrySet()) {
            newMap.put(entry.getValue(), entry.getKey());
        }
        return new TreeMap<String, String>(newMap);
    }
    return new TreeMap<String, String>(passedMap);
}

AngularJS - Access to child scope

You can try this:

$scope.child = {} //declare it in parent controller (scope)

then in child controller (scope) add:

var parentScope = $scope.$parent;
parentScope.child = $scope;

Now the parent has access to the child's scope.

Slide a layout up from bottom of screen

Use these animations:

bottom_up.xml

<?xml version="1.0" encoding="utf-8"?>
 <set xmlns:android="http://schemas.android.com/apk/res/android">
   <translate android:fromYDelta="75%p" android:toYDelta="0%p" 
    android:fillAfter="true"
 android:duration="500"/>
</set>

bottom_down.xml

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

<translate android:fromYDelta="0%p" android:toYDelta="100%p" android:fillAfter="true"
            android:interpolator="@android:anim/linear_interpolator"
    android:duration="500" />

</set>

Use this code in your activity for hiding/animating your view:

Animation bottomUp = AnimationUtils.loadAnimation(getContext(),
            R.anim.bottom_up);
ViewGroup hiddenPanel = (ViewGroup)findViewById(R.id.hidden_panel);
hiddenPanel.startAnimation(bottomUp);
hiddenPanel.setVisibility(View.VISIBLE);

PHP display current server path

php can call command line operations so

echo exec("pwd");

JAX-WS - Adding SOAP Headers

In jaxws-rt-2.2.10-ources.jar!\com\sun\xml\ws\transport\http\client\HttpTransportPipe.java:

public Packet process(Packet request) {
        Map<String, List<String>> userHeaders = (Map<String, List<String>>) request.invocationProperties.get(MessageContext.HTTP_REQUEST_HEADERS);
        if (userHeaders != null) {
            reqHeaders.putAll(userHeaders);

So, Map<String, List<String>> from requestContext with key MessageContext.HTTP_REQUEST_HEADERS will be copied to SOAP headers. Sample of Application Authentication with JAX-WS via headers

BindingProvider.USERNAME_PROPERTY and BindingProvider.PASSWORD_PROPERTY keys are processed special way in HttpTransportPipe.addBasicAuth(), adding standard basic authorization Authorization header.

See also Message Context in JAX-WS

How can I add a line to a file in a shell script?

As far as I understand, you want to prepend column1, column2, column3 to your existing one, two, three.

I would use ed in place of sed, since sed write on the standard output and not in the file.

The command:

printf '0a\ncolumn1, column2, column3\n.\nw\n' | ed testfile.csv

should do the work.

perl -i is worth taking a look as well.

Uncaught ReferenceError: <function> is not defined at HTMLButtonElement.onclick

Same Problem I had... I was writing all the script in a seperate file and was adding it through tag into the end of the HTML file after body tag. After moving the the tag inside the body tag it works fine. before :

</body>
<script>require('../script/viewLog.js')</script>

after :

<script>require('../script/viewLog.js')</script>
</body>

Run Java Code Online

Ideone is the best site for the online code running, debugging and it provides extra performance stats also.

Without Sign Up, you can run code upto of maximum 5 sec, and for signup, upto a max of 15 sec. And for Signup, the code management and history is also too good.

However, it has some maximum amount of submissions per month for registered users.

www.ideone.com

It supports more than 40 languages, and is integrated with SPOJ and RecruitCoders.

Where is web.xml in Eclipse Dynamic Web Project

If you missed to check the "generate web.xml" option when creating a new project, no worries If it is a Dynamic Web Project in your project right click on "Deployment Descriptor:...." and Click on "Generate Deployment Descriptor Stub" this will create a minimal /webapp/WEB-INF/web.xml.

Render a string in HTML and preserve spaces and linebreaks

You can use white-space: pre-line to preserve line breaks in formatting. There is no need to manually insert html elements.

.popover {
    white-space: pre-line;    
}

or add to your html element style="white-space: pre-line;"

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

I was having the same issue using an API call which responded in ISO 8601 format. Working in Chrome this worked: `

// date variable from an api all in ISO 8601 format yyyy-mm-dd hh:mm:ss
  var date = oDate['events']['event'][0]['start_time'];
  var eventDate = new Date();
  var outputDate = eventDate.toDateString();

`

but this didn't work with firefox.

Above answer helped me format it correctly for firefox:

 // date variable from an api all in ISO 8601 format yyyy-mm-dd hh:mm:ss
 var date = oDate['events']['event'][0]['start_time'];
 var eventDate = new Date(date.replace(/-/g,"/");
 var outputDate = eventDate.toDateString();

Spell Checker for Python

Try jamspell - it works pretty well for automatic spelling correction:

import jamspell

corrector = jamspell.TSpellCorrector()
corrector.LoadLangModel('en.bin')

corrector.FixFragment('Some sentnec with error')
# u'Some sentence with error'

corrector.GetCandidates(['Some', 'sentnec', 'with', 'error'], 1)
# ('sentence', 'senate', 'scented', 'sentinel')

WHERE statement after a UNION in SQL?

You probably need to wrap the UNION in a sub-SELECT and apply the WHERE clause afterward:

SELECT * FROM (
    SELECT * FROM Table1 WHERE Field1 = Value1
    UNION
    SELECT * FROM Table2 WHERE Field1 = Value2
) AS t WHERE Field2 = Value3

Basically, the UNION is looking for two complete SELECT statements to combine, and the WHERE clause is part of the SELECT statement.

It may make more sense to apply the outer WHERE clause to both of the inner queries. You'll probably want to benchmark the performance of both approaches and see which works better for you.

How to write a switch statement in Ruby

$age =  5
case $age
when 0 .. 2
   puts "baby"
when 3 .. 6
   puts "little child"
when 7 .. 12
   puts "child"
when 13 .. 18
   puts "youth"
else
   puts "adult"
end

See "Ruby - if...else, case, unless" for more information.

Create a basic matrix in C (input by user !)

int rows, cols , i, j;
printf("Enter number of rows and cols for the matrix: \n");
scanf("%d %d",&rows, &cols);

int mat[rows][cols];

printf("enter the matrix:");

for(i = 0; i < rows ; i++)
    for(j = 0; j < cols; j++)
        scanf("%d", &mat[i][j]);

printf("\nThe Matrix is:\n");
for(i = 0; i < rows ; i++)
{
    for(j = 0; j < cols; j++)
    {
        printf("%d",mat[i][j]);
        printf("\t");
    }
    printf("\n");
}

}

how to prevent this error : Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in ... on line 11

The proper syntax is (in example):

$query = mysql_query('SELECT * FROM beer ORDER BY quality');
while($row = mysql_fetch_assoc($query)) $results[] = $row;

How to do join on multiple criteria, returning all combinations of both criteria

SELECT  aa.*,
        bb.meal
FROM    table1 aa
        INNER JOIN table2 bb
            ON aa.tableseat = bb.tableseat AND
                aa.weddingtable = bb.weddingtable
        INNER JOIN
        (
            SELECT  a.tableSeat
            FROM    table1 a
                    INNER JOIN table2 b
                        ON a.tableseat = b.tableseat AND
                            a.weddingtable = b.weddingtable
            WHERE b.meal IN ('chicken', 'steak')
            GROUP by a.tableSeat
            HAVING COUNT(DISTINCT b.Meal) = 2
        ) c ON aa.tableseat = c.tableSeat

TypeScript hashmap/dictionary interface

var x : IHash = {};
x['key1'] = 'value1';
x['key2'] = 'value2';

console.log(x['key1']);
// outputs value1

console.log(x['key2']);
// outputs value2

If you would like to then iterate through your dictionary, you can use.

Object.keys(x).forEach((key) => {console.log(x[key])});

Object.keys returns all the properties of an object, so it works nicely for returning all the values from dictionary styled objects.

You also mentioned a hashmap in your question, the above definition is for a dictionary style interface. Therefore the keys will be unique, but the values will not.

You could use it like a hashset by just assigning the same value to the key and its value.

if you wanted the keys to be unique and with potentially different values, then you just have to check if the key exists on the object before adding to it.

var valueToAdd = 'one';
if(!x[valueToAdd])
   x[valueToAdd] = valueToAdd;

or you could build your own class to act as a hashset of sorts.

Class HashSet{
  private var keys: IHash = {};
  private var values: string[] = [];

  public Add(key: string){
    if(!keys[key]){
      values.push(key);
      keys[key] = key;
    }
  }

  public GetValues(){
    // slicing the array will return it by value so users cannot accidentally
    // start playing around with your array
    return values.slice();
  }
}

How to change JFrame icon

Just add the following code:

setIconImage(new ImageIcon(PathOfFile).getImage());

How to send an email with Python?

While indenting your code in the function (which is ok), you did also indent the lines of the raw message string. But leading white space implies folding (concatenation) of the header lines, as described in sections 2.2.3 and 3.2.3 of RFC 2822 - Internet Message Format:

Each header field is logically a single line of characters comprising the field name, the colon, and the field body. For convenience however, and to deal with the 998/78 character limitations per line, the field body portion of a header field can be split into a multiple line representation; this is called "folding".

In the function form of your sendmail call, all lines are starting with white space and so are "unfolded" (concatenated) and you are trying to send

From: [email protected]    To: [email protected]    Subject: Hello!    This message was sent with Python's smtplib.

Other than our mind suggests, smtplib will not understand the To: and Subject: headers any longer, because these names are only recognized at the beginning of a line. Instead smtplib will assume a very long sender email address:

[email protected]    To: [email protected]    Subject: Hello!    This message was sent with Python's smtplib.

This won't work and so comes your Exception.

The solution is simple: Just preserve the message string as it was before. This can be done by a function (as Zeeshan suggested) or right away in the source code:

import smtplib

def sendMail(FROM,TO,SUBJECT,TEXT,SERVER):
    """this is some test documentation in the function"""
    message = """\
From: %s
To: %s
Subject: %s

%s
""" % (FROM, ", ".join(TO), SUBJECT, TEXT)
    # Send the mail
    server = smtplib.SMTP(SERVER)
    server.sendmail(FROM, TO, message)
    server.quit()

Now the unfolding does not occur and you send

From: [email protected]
To: [email protected]
Subject: Hello!

This message was sent with Python's smtplib.

which is what works and what was done by your old code.

Note that I was also preserving the empty line between headers and body to accommodate section 3.5 of the RFC (which is required) and put the include outside the function according to the Python style guide PEP-0008 (which is optional).

What to do on TransactionTooLargeException

If you need to investigate which Parcel is causing your crash, you should consider trying TooLargeTool.

(I found this as a comment from @Max Spencer under the accepted answer and it was helpful in my case.)

Remove quotes from a character vector in R

I'm just guessing, is this in the ball park of what you're trying to achieve?

> a <- "a"
> a
[1] "a" # quote yes
> as.factor(a)
[1] a #quote no

Get first element in PHP stdObject

Update PHP 7.4

Curly brace access syntax is deprecated since PHP 7.4

Update 2019

Moving on to the best practices of OOPS, @MrTrick's answer must be marked as correct, although my answer provides a hacked solution its not the best method.

Simply iterate its using {}

Example:

$videos{0}->id

This way your object is not destroyed and you can easily iterate through object.

For PHP 5.6 and below use this

$videos{0}['id']

Both array() and the stdClass objects can be accessed using the current() key() next() prev() reset() end() functions.

So, if your object looks like

object(stdClass)#19 (3) {
  [0]=>
  object(stdClass)#20 (22) {
    ["id"]=>
    string(1) "123"
  etc...

Then you can just do;

$id = reset($obj)->id; //Gets the 'id' attr of the first entry in the object

If you need the key for some reason, you can do;

reset($obj); //Ensure that we're at the first element
$key = key($obj);

Hope that works for you. :-) No errors, even in super-strict mode, on PHP 5.4


2022 Update:
After PHP 7.4, using current(), end(), etc functions on objects is deprecated.

In newer versions of PHP, use the ArrayIterator class:

$objIterator = new ArrayIterator($obj);

$id = $objIterator->current()->id; // Gets the 'id' attr of the first entry in the object

$key = $objIterator->key(); // and gets the key

How to refresh token with Google API client?

The access type should be set to offline. state is a variable you set for your own use, not the API's use.

Make sure you have the latest version of the client library and add:

$client->setAccessType('offline');

See Forming the URL for an explanation of the parameters.

How can I remove "\r\n" from a string in C#? Can I use a regular expression?

Nicer code for this:

yourstring = yourstring.Replace(System.Environment.NewLine, string.Empty);

Redefining the Index in a Pandas DataFrame object

Why don't you simply use set_index method?

In : col = ['a','b','c']

In : data = DataFrame([[1,2,3],[10,11,12],[20,21,22]],columns=col)

In : data
Out:
    a   b   c
0   1   2   3
1  10  11  12
2  20  21  22

In : data2 = data.set_index('a')

In : data2
Out:
     b   c
a
1    2   3
10  11  12
20  21  22

How to remove an element from a list by index

Use del and specify the index of the element you want to delete:

>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> del a[-1]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8]

Also supports slices:

>>> del a[2:4]
>>> a
[0, 1, 4, 5, 6, 7, 8, 9]

Here is the section from the tutorial.

IE8 support for CSS Media Query

Internet Explorer versions before IE9 do not support media queries.

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

For example:

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

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

Check if a Postgres JSON array contains a string

As of PostgreSQL 9.4, you can use the ? operator:

select info->>'name' from rabbits where (info->'food')::jsonb ? 'carrots';

You can even index the ? query on the "food" key if you switch to the jsonb type instead:

alter table rabbits alter info type jsonb using info::jsonb;
create index on rabbits using gin ((info->'food'));
select info->>'name' from rabbits where info->'food' ? 'carrots';

Of course, you probably don't have time for that as a full-time rabbit keeper.

Update: Here's a demonstration of the performance improvements on a table of 1,000,000 rabbits where each rabbit likes two foods and 10% of them like carrots:

d=# -- Postgres 9.3 solution
d=# explain analyze select info->>'name' from rabbits where exists (
d(# select 1 from json_array_elements(info->'food') as food
d(#   where food::text = '"carrots"'
d(# );
 Execution time: 3084.927 ms

d=# -- Postgres 9.4+ solution
d=# explain analyze select info->'name' from rabbits where (info->'food')::jsonb ? 'carrots';
 Execution time: 1255.501 ms

d=# alter table rabbits alter info type jsonb using info::jsonb;
d=# explain analyze select info->'name' from rabbits where info->'food' ? 'carrots';
 Execution time: 465.919 ms

d=# create index on rabbits using gin ((info->'food'));
d=# explain analyze select info->'name' from rabbits where info->'food' ? 'carrots';
 Execution time: 256.478 ms

Path of assets in CSS files in Symfony 2

I had the same problem and I just tried using the following as a workaround. Seems to work so far. You can even create a dummy template that just contains references to all those static assets.

{% stylesheets
    output='assets/fonts/glyphicons-halflings-regular.ttf'
    'bundles/bootstrap/fonts/glyphicons-halflings-regular.ttf'
%}{% endstylesheets %}

Notice the omission of any output which means nothing shows up on the template. When I run assetic:dump the files are copied over to the desired location and the css includes work as expected.

How To Set Up GUI On Amazon EC2 Ubuntu server

For LXDE/Lubuntu


1. connect to your instance (local forwarding port 5901)

ssh -L 5901:localhost:5901 -i "xxx.pem" [email protected]

2. Install packages

sudo apt update && sudo apt upgrade
sudo apt-get install xorg lxde vnc4server lubuntu-desktop

3. Create /etc/lightdm/lightdm.conf

sudo nano /etc/lightdm/lightdm.conf

4. Copy and paste the following into the lightdm.conf and save

[SeatDefaults]
allow-guest=false
user-session=LXDE
#user-session=Lubuntu

5. setup vncserver (you will be asked to create a password for the vncserver)

vncserver
sudo echo "lxpanel & /usr/bin/lxsession -s LXDE &" >> ~/.vnc/xstartup

6. Restart your instance and reconnect

sudo reboot
ssh -L 5901:localhost:5901 -i "xxx.pem" [email protected]

7. Start vncserver

vncserver -geometry 1280x800

8. In your Remote Desktop Client (e.g. Remmina) set Server to localhost:5901 and protocol to VNC

CSS3 Transparency + Gradient

Here is my code:

background: #e8e3e3; /* Old browsers */
  background: -moz-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%, rgba(246, 242, 242, 0.95) 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(232, 227, 227, 0.95)), color-stop(100%,rgba(246, 242, 242, 0.95))); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(top,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* IE10+ */
  background: linear-gradient(to bottom,  rgba(232, 227, 227, 0.95) 0%,rgba(246, 242, 242, 0.95) 100%); /* W3C */
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='rgba(232, 227, 227, 0.95)', endColorstr='rgba(246, 242, 242, 0.95)',GradientType=0 ); /* IE6-9 */

How to use OKHTTP to make a post request?

If you want to post parameter in okhttp as body content which can be encrypted string with content-type as "application/x-www-form-urlencoded" you can first use URLEncoder to encode the data and then use :

final MediaType MEDIA_TYPE_MARKDOWN = MediaType.parse("application/x-www-form-urlencoded");

okhttp3.Request request = new okhttp3.Request.Builder()
    .url(urlOfServer)
    .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, yourBodyDataToPostOnserver))
    .build();

you can add header according to your requirement.

How does one extract each folder name from a path?

This is good in the general case:

yourPath.Split(@"\/", StringSplitOptions.RemoveEmptyEntries)

There is no empty element in the returned array if the path itself ends in a (back)slash (e.g. "\foo\bar\"). However, you will have to be sure that yourPath is really a directory and not a file. You can find out what it is and compensate if it is a file like this:

if(Directory.Exists(yourPath)) {
  var entries = yourPath.Split(@"\/", StringSplitOptions.RemoveEmptyEntries);
}
else if(File.Exists(yourPath)) {
  var entries = Path.GetDirectoryName(yourPath).Split(
                    @"\/", StringSplitOptions.RemoveEmptyEntries);
}
else {
  // error handling
}

I believe this covers all bases without being too pedantic. It will return a string[] that you can iterate over with foreach to get each directory in turn.

If you want to use constants instead of the @"\/" magic string, you need to use

var separators = new char[] {
  Path.DirectorySeparatorChar,  
  Path.AltDirectorySeparatorChar  
};

and then use separators instead of @"\/" in the code above. Personally, I find this too verbose and would most likely not do it.

Ansible: deploy on multiple hosts in the same time

I played a long time with things like ls -1 | xargs -P to parallelize my playbooks runs. But to get a prettier display, and simplicity I wrote a simple Python tool to do it, ansible-parallel.

It goes like this:

pip install ansible-parallel
ansible-parallel *.yml

To answer precisely to the original question (how to run some tasks first, and the rest in parallel), it can be solved by removing the 3 includes and running:

ansible-playbook say_hi.yml
ansible-parallel load_balancers.yml webservers.yml dbservers.yml

NameError: name 'reduce' is not defined in Python

Or if you use the six library

from six.moves import reduce

How to have click event ONLY fire on parent DIV, not children?

You can use bubbling in your favor:

$('.foobar').on('click', function(e) {
    // do your thing.
}).on('click', 'div', function(e) {
    // clicked on descendant div
    e.stopPropagation();
});

Python one-line "for" expression

for item in array: array2.append (item)

Or, in this case:

array2 += array

Find duplicate entries in a column

Using:

  SELECT t.ctn_no
    FROM YOUR_TABLE t
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

...will show you the ctn_no value(s) that have duplicates in your table. Adding criteria to the WHERE will allow you to further tune what duplicates there are:

  SELECT t.ctn_no
    FROM YOUR_TABLE t
   WHERE t.s_ind = 'Y'
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

If you want to see the other column values associated with the duplicate, you'll want to use a self join:

SELECT x.*
  FROM YOUR_TABLE x
  JOIN (SELECT t.ctn_no
          FROM YOUR_TABLE t
      GROUP BY t.ctn_no
        HAVING COUNT(t.ctn_no) > 1) y ON y.ctn_no = x.ctn_no

How to set DataGrid's row Background, based on a property value using data bindings

Use a DataTrigger:

<DataGrid ItemsSource="{Binding YourItemsSource}">
    <DataGrid.RowStyle>
        <Style TargetType="DataGridRow"> 
            <Style.Triggers>
                <DataTrigger Binding="{Binding State}" Value="State1">
                    <Setter Property="Background" Value="Red"></Setter>
                </DataTrigger>
                <DataTrigger Binding="{Binding State}" Value="State2">
                    <Setter Property="Background" Value="Green"></Setter>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.RowStyle>
</DataGrid>

How to import and export components using React + ES6 + webpack?

To export a single component in ES6, you can use export default as follows:

class MyClass extends Component {
 ...
}

export default MyClass;

And now you use the following syntax to import that module:

import MyClass from './MyClass.react'

If you are looking to export multiple components from a single file the declaration would look something like this:

export class MyClass1 extends Component {
 ...
}

export class MyClass2 extends Component {
 ...
}

And now you can use the following syntax to import those files:

import {MyClass1, MyClass2} from './MyClass.react'