Programs & Examples On #Gambit

Questions about the Gambit-C implementation of the Scheme programming language.

How do I determine if a port is open on a Windows server?

On Windows Server you can use

netstat -an | where{$_.Contains("Yourport")}

Insert into a MySQL table or update if exists

Use INSERT ... ON DUPLICATE KEY UPDATE

QUERY:

INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE    
name="A", age=19

Separation of business logic and data access in django

In Django, MVC structure is as Chris Pratt said, different from classical MVC model used in other frameworks, I think the main reason for doing this is avoiding a too strict application structure, like happens in others MVC frameworks like CakePHP.

In Django, MVC was implemented in the following way:

View layer is splitted in two. The views should be used only to manage HTTP requests, they are called and respond to them. Views communicate with the rest of your application (forms, modelforms, custom classes, of in simple cases directly with models). To create the interface we use Templates. Templates are string-like to Django, it maps a context into them, and this context was communicated to the view by the application (when view asks).

Model layer gives encapsulation, abstraction, validation, intelligence and makes your data object-oriented (they say someday DBMS will also). This doesn't means that you should make huge models.py files (in fact a very good advice is to split your models in different files, put them into a folder called 'models', make an '__init__.py' file into this folder where you import all your models and finally use the attribute 'app_label' of models.Model class). Model should abstract you from operating with data, it will make your application simpler. You should also, if required, create external classes, like "tools" for your models.You can also use heritage in models, setting the 'abstract' attribute of your model's Meta class to 'True'.

Where is the rest? Well, small web applications generally are a sort of an interface to data, in some small program cases using views to query or insert data would be enough. More common cases will use Forms or ModelForms, which are actually "controllers". This is not other than a practical solution to a common problem, and a very fast one. It's what a website use to do.

If Forms are not enogh for you, then you should create your own classes to do the magic, a very good example of this is admin application: you can read ModelAmin code, this actually works as a controller. There is not a standard structure, I suggest you to examine existing Django apps, it depends on each case. This is what Django developers intended, you can add xml parser class, an API connector class, add Celery for performing tasks, twisted for a reactor-based application, use only the ORM, make a web service, modify the admin application and more... It's your responsability to make good quality code, respect MVC philosophy or not, make it module based and creating your own abstraction layers. It's very flexible.

My advice: read as much code as you can, there are lots of django applications around, but don't take them so seriously. Each case is different, patterns and theory helps, but not always, this is an imprecise cience, django just provide you good tools that you can use to aliviate some pains (like admin interface, web form validation, i18n, observer pattern implementation, all the previously mentioned and others), but good designs come from experienced designers.

PS.: use 'User' class from auth application (from standard django), you can make for example user profiles, or at least read its code, it will be useful for your case.

How do I change the default schema in sql developer?

Alternatively, just select 'Other Users' one of the element shows on the left hand side bottom of the current schema.

Select what ever the schema you want from the available list.

enter image description here

Delete all files of specific type (extension) recursively down a directory using a batch file

I don't have enough reputation to add comment, so I posted this as an answer. But for original issue with this command:

@echo off
FOR %%p IN (C:\Users\vexe\Pictures\sample) DO FOR %%t IN (*.jpg) DO del /s %%p\%%t

The first For is lacking recursive syntax, it should be:

@echo off
FOR /R %%p IN (C:\Users\vexe\Pictures\sample) DO FOR %%t IN (*.jpg) DO del /s %%p\%%t

You can just do:

FOR %%p IN (C:\Users\0300092544\Downloads\Ces_Sce_600) DO @ECHO %%p

to show the actual output.

Cannot set some HTTP headers when using System.Net.WebRequest

Anytime you're changing the headers of an HttpWebRequest, you need to use the appropriate properties on the object itself, if they exist. If you have a plain WebRequest, be sure to cast it to an HttpWebRequest first. Then Referrer in your case can be accessed via ((HttpWebRequest)request).Referrer, so you don't need to modify the header directly - just set the property to the right value. ContentLength, ContentType, UserAgent, etc, all need to be set this way.

IMHO, this is a shortcoming on MS part...setting the headers via Headers.Add() should automatically call the appropriate property behind the scenes, if that's what they want to do.

Get HTML code using JavaScript with a URL

For an external (cross-site) solution, you can use: Get contents of a link tag with JavaScript - not CSS

It uses $.ajax() function, so it includes jquery.

React Native add bold or italics to single words in <Text> field

you can use https://www.npmjs.com/package/react-native-parsed-text

_x000D_
_x000D_
import ParsedText from 'react-native-parsed-text';_x000D_
 _x000D_
class Example extends React.Component {_x000D_
  static displayName = 'Example';_x000D_
 _x000D_
  handleUrlPress(url) {_x000D_
    LinkingIOS.openURL(url);_x000D_
  }_x000D_
 _x000D_
  handlePhonePress(phone) {_x000D_
    AlertIOS.alert(`${phone} has been pressed!`);_x000D_
  }_x000D_
 _x000D_
  handleNamePress(name) {_x000D_
    AlertIOS.alert(`Hello ${name}`);_x000D_
  }_x000D_
 _x000D_
  handleEmailPress(email) {_x000D_
    AlertIOS.alert(`send email to ${email}`);_x000D_
  }_x000D_
 _x000D_
  renderText(matchingString, matches) {_x000D_
    // matches => ["[@michel:5455345]", "@michel", "5455345"]_x000D_
    let pattern = /\[(@[^:]+):([^\]]+)\]/i;_x000D_
    let match = matchingString.match(pattern);_x000D_
    return `^^${match[1]}^^`;_x000D_
  }_x000D_
 _x000D_
  render() {_x000D_
    return (_x000D_
      <View style={styles.container}>_x000D_
        <ParsedText_x000D_
          style={styles.text}_x000D_
          parse={_x000D_
            [_x000D_
              {type: 'url',                       style: styles.url, onPress: this.handleUrlPress},_x000D_
              {type: 'phone',                     style: styles.phone, onPress: this.handlePhonePress},_x000D_
              {type: 'email',                     style: styles.email, onPress: this.handleEmailPress},_x000D_
              {pattern: /Bob|David/,              style: styles.name, onPress: this.handleNamePress},_x000D_
              {pattern: /\[(@[^:]+):([^\]]+)\]/i, style: styles.username, onPress: this.handleNamePress, renderText: this.renderText},_x000D_
              {pattern: /42/,                     style: styles.magicNumber},_x000D_
              {pattern: /#(\w+)/,                 style: styles.hashTag},_x000D_
            ]_x000D_
          }_x000D_
          childrenProps={{allowFontScaling: false}}_x000D_
        >_x000D_
          Hello this is an example of the ParsedText, links like http://www.google.com or http://www.facebook.com are clickable and phone number 444-555-6666 can call too._x000D_
          But you can also do more with this package, for example Bob will change style and David too. [email protected]_x000D_
          And the magic number is 42!_x000D_
          #react #react-native_x000D_
        </ParsedText>_x000D_
      </View>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
 _x000D_
const styles = StyleSheet.create({_x000D_
  container: {_x000D_
    flex: 1,_x000D_
    justifyContent: 'center',_x000D_
    alignItems: 'center',_x000D_
    backgroundColor: '#F5FCFF',_x000D_
  },_x000D_
 _x000D_
  url: {_x000D_
    color: 'red',_x000D_
    textDecorationLine: 'underline',_x000D_
  },_x000D_
 _x000D_
  email: {_x000D_
    textDecorationLine: 'underline',_x000D_
  },_x000D_
 _x000D_
  text: {_x000D_
    color: 'black',_x000D_
    fontSize: 15,_x000D_
  },_x000D_
 _x000D_
  phone: {_x000D_
    color: 'blue',_x000D_
    textDecorationLine: 'underline',_x000D_
  },_x000D_
 _x000D_
  name: {_x000D_
    color: 'red',_x000D_
  },_x000D_
 _x000D_
  username: {_x000D_
    color: 'green',_x000D_
    fontWeight: 'bold'_x000D_
  },_x000D_
 _x000D_
  magicNumber: {_x000D_
    fontSize: 42,_x000D_
    color: 'pink',_x000D_
  },_x000D_
 _x000D_
  hashTag: {_x000D_
    fontStyle: 'italic',_x000D_
  },_x000D_
 _x000D_
});
_x000D_
_x000D_
_x000D_

Get the records of last month in SQL server

One way to do it is using the DATEPART function:

select field1, field2, fieldN from TABLE where DATEPART(month, date_created) = 4 
and DATEPART(year, date_created) = 2009

will return all dates in april. For last month (ie, previous to current month) you can use GETDATE and DATEADD as well:

select field1, field2, fieldN from TABLE where DATEPART(month, date_created) 
= (DATEPART(month, GETDATE()) - 1) and 
DATEPART(year, date_created) = DATEPART(year, DATEADD(m, -1, GETDATE()))

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

It is possible that your compiler and the resources installed around it were somehow incomplete. I recommend re-installing your compiler: it should work after that.

How to get default gateway in Mac OSX

For getting the list of ip addresses associated, you can use netstat command

netstat -rn 

This gives a long list of ip addresses and it is not easy to find the required field. The sample result is as following:

Routing tables
Internet:
Destination        Gateway            Flags        Refs      Use   Netif Expire
default            192.168.195.1      UGSc           17        0     en2
127                127.0.0.1          UCS             0        0     lo0
127.0.0.1          127.0.0.1          UH              1   254107     lo0
169.254            link#7             UCS             0        0     en2
192.168.195        link#7             UCS             3        0     en2
192.168.195.1      0:27:22:67:35:ee   UHLWIi         22      397     en2   1193
192.168.195.5      127.0.0.1          UHS             0        0     lo0

More result is truncated.......

The ip address of gateway is in the first line; one with default at its first column.

To display only the selected lines of result, we can use grep command along with netstat

netstat -rn | grep 'default'

This command filters and displays those lines of result having default. In this case, you can see result like following:

default            192.168.195.1      UGSc           14        0     en2

If you are interested in finding only the ip address of gateway and nothing else you can further filter the result using awk. The awk command matches pattern in the input result and displays the output. This can be useful when you are using your result directly in some program or batch job.

netstat -rn | grep 'default' | awk '{print $2}'

The awk command tells to match and print the second column of the result in the text. The final result thus looks like this:

192.168.195.1

In this case, netstat displays all result, grep only selects the line with 'default' in it, and awk further matches the pattern to display the second column in the text.

You can similarly use route -n get default command to get the required result. The full command is

route -n get default | grep 'gateway' | awk '{print $2}'

These commands work well in linux as well as unix systems and MAC OS.

How do I get extra data from intent on Android?

If you are trying to get extra data in fragments then you can try using:

Place data using:

Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER);

Get data using:

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {


  getArguments().getInt(ARG_SECTION_NUMBER);
  getArguments().getString(ARG_SECTION_STRING);
  getArguments().getBoolean(ARG_SECTION_BOOL);
  getArguments().getChar(ARG_SECTION_CHAR);
  getArguments().getByte(ARG_SECTION_DATA);

}

import android packages cannot be resolved

I just had the same problem after accepting a Java update--scores of build errors and android import not recognized. On checking the build path in Project=>Properties, I found that the check box for Android 4.3 had somehow gotten cleared. Checking it resolved all the import errors without my even having to restart the IDE or run a project clean.

How to use regex in file find

Just little elaboration of regex for search a directory and file

Find a directroy with name like book

find . -name "*book*" -type d

Find a file with name like book word

find . -name "*book*" -type f

Floating elements within a div, floats outside of div. Why?

There's nothing missing. Float was designed for the case where you want an image (for example) to sit beside several paragraphs of text, so the text flows around the image. That wouldn't happen if the text "stretched" the container. Your first paragraph would end, and then your next paragraph would begin under the image (possibly several hundred pixels below).

And that's why you're getting the result you are.

Characters allowed in a URL

RFC3986 defines two sets of characters you can use in a URI:

  • Reserved Characters: :/?#[]@!$&'()*+,;=

    reserved = gen-delims / sub-delims

    gen-delims = ":" / "/" / "?" / "#" / "[" / "]" / "@"

    sub-delims = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="

    The purpose of reserved characters is to provide a set of delimiting characters that are distinguishable from other data within a URI. URIs that differ in the replacement of a reserved character with its corresponding percent-encoded octet are not equivalent.

  • Unreserved Characters: A-Za-z0-9-_.~

    unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"

    Characters that are allowed in a URI but do not have a reserved purpose are called unreserved.

Can you style html form buttons with css?

Yes you can target those specificaly using input[type=submit] e.g.

.myFormClass input[type=submit] {
  margin: 10px;
  color: white;
  background-color: blue;
}

Adding author name in Eclipse automatically to existing files

You can control select all customised classes and methods, and right-click, choose "Source", then select "Generate Element Comment". You should get what you want.

If you want to modify the Code Template then you can go to Preferences -- Java -- Code Style -- Code Templates, then do whatever you want.

Pretty git branch graphs

Although sometimes I use gitg, always come back to command line:

[alias]
    #quick look at all repo
    loggsa = log --color --date-order --graph --oneline --decorate --simplify-by-decoration --all
    #quick look at active branch (or refs pointed)
    loggs  = log --color --date-order --graph --oneline --decorate --simplify-by-decoration
    #extend look at all repo
    logga  = log --color --date-order --graph --oneline --decorate --all
    #extend look at active branch
    logg   = log --color --date-order --graph --oneline --decorate
    #Look with date
    logda  = log --color --date-order --date=local --graph --format=\"%C(auto)%h%Creset %C(blue bold)%ad%Creset %C(auto)%d%Creset %s\" --all
    logd   = log --color --date-order --date=local --graph --format=\"%C(auto)%h%Creset %C(blue bold)%ad%Creset %C(auto)%d%Creset %s\"        
    #Look with relative date
    logdra = log --color --date-order --graph --format=\"%C(auto)%h%Creset %C(blue bold)%ar%Creset %C(auto)%d%Creset %s\" --all
    logdr = log --color --date-order --graph --format=\"%C(auto)%h%Creset %C(blue bold)%ar%Creset %C(auto)%d%Creset %s\"  

    loga   = log --graph --color --decorate --all

    # For repos without subject body commits (vim repo, git-svn clones)
    logt  = log --graph --color --format=\"%C(auto)%h %d %<|(100,trunc) %s\"
    logta  = log --graph --color --format=\"%C(auto)%h %d %<|(100,trunc) %s\" --all        
    logtsa = log --graph --color --format=\"%C(auto)%h %d %<|(100,trunc) %s\" --all --simplify-by-decoration 

As you can see is almost a keystroke saving aliases, based on:

  • --color: clear look
  • --graph: visualize parents
  • --date-order: most understandable look at repo
  • --decorate: who is who
  • --oneline: Many times all you need to know about a commit
  • --simplify-by-decoration: basic for a first look (just tags, relevant merges, branches)
  • --all: saving keystrokes with all alias with and without this option
  • --date=relative (%ar): Understand activity in repo (sometimes a branch is few commits near master but months ago from him)

See in recent version of git (1.8.5 and above) you can benefit from %C(auto) in decorate placeholder %d

From here all you need is a good understand of gitrevisions to filter whatever you need (something like master..develop, where --simplify-merges could help with long term branches)

The power behind command line is the quickly config based on your needs (understand a repo isn't a unique key log configuration, so adding --numstat, or --raw, or --name-status is sometimes needed. Here git log and aliases are fast, powerful and (with time) the prettiest graph you can achieved. Even more, with output showed by default through a pager (say less) you can always search quickly inside results. Not convinced? You can always parse the result with projects like gitgraph

“Unable to find manifest signing certificate in the certificate store” - even when add new key

To sign an assembly with a strong name using attributes

Open AssemblyInfo.cs (in $(SolutionDir)\Properties)

the AssemblyKeyFileAttribute or the AssemblyKeyNameAttribute, specifying the name of the file or container that contains the key pair to use when signing the assembly with a strong name.

add the following code:

[assembly:AssemblyKeyFileAttribute("keyfile.snk")]

Finding out the name of the original repository you cloned from in Git

I use this:

basename $(git remote get-url origin) .git

Which returns something like gitRepo. (Remove the .git at the end of the command to return something like gitRepo.git.)

(Note: It requires Git version 2.7.0 or later)

How to use format() on a moment.js duration?

const duration = moment.duration(62, 'hours');
const n = 24 * 60 * 60 * 1000;
const days = Math.floor(duration / n);
const str = moment.utc(duration % n).format('H [h] mm [min] ss [s]');
console.log(`${days > 0 ? `${days} ${days == 1 ? 'day' : 'days'} ` : ''}${str}`);

Prints:

2 days 14 h 00 min 00 s

Circle button css

For div tag there is already default property display:block given by browser. For anchor tag there is not display property given by browser. You need to add display property to it. That's why use display:block or display:inline-block. It will work.

_x000D_
_x000D_
.btn {_x000D_
  display:block;_x000D_
  height: 300px;_x000D_
  width: 300px;_x000D_
  border-radius: 50%;_x000D_
  border: 1px solid red;_x000D_
  _x000D_
}
_x000D_
<a class="btn" href="#"><i class="ion-ios-arrow-down"></i></a>
_x000D_
_x000D_
_x000D_

Apache won't start in wamp

Sometimes it is Skype or another application "Holding" on to port 80. Jusct close Skype

How to make Twitter Bootstrap menu dropdown on hover rather than click

This works for WordPress Bootstrap:

.navbar .nav > li > .dropdown-menu:after,
.navbar .nav > li > .dropdown-menu:before {
    content: none;
}

Conditional HTML Attributes using Razor MVC3

Note you can do something like this(at least in MVC3):

<td align="left" @(isOddRow ? "class=TopBorder" : "style=border:0px") >

What I believed was razor adding quotes was actually the browser. As Rism pointed out when testing with MVC 4(I haven't tested with MVC 3 but I assume behavior hasn't changed), this actually produces class=TopBorder but browsers are able to parse this fine. The HTML parsers are somewhat forgiving on missing attribute quotes, but this can break if you have spaces or certain characters.

<td align="left" class="TopBorder" >

OR

<td align="left" style="border:0px" >

What goes wrong with providing your own quotes

If you try to use some of the usual C# conventions for nested quotes, you'll end up with more quotes than you bargained for because Razor is trying to safely escape them. For example:

<button type="button" @(true ? "style=\"border:0px\"" : string.Empty)>

This should evaluate to <button type="button" style="border:0px"> but Razor escapes all output from C# and thus produces:

style=&quot;border:0px&quot;

You will only see this if you view the response over the network. If you use an HTML inspector, often you are actually seeing the DOM, not the raw HTML. Browsers parse HTML into the DOM, and the after-parsing DOM representation already has some niceties applied. In this case the Browser sees there aren't quotes around the attribute value, adds them:

style="&quot;border:0px&quot;"

But in the DOM inspector HTML character codes display properly so you actually see:

style=""border:0px""

In Chrome, if you right-click and select Edit HTML, it switch back so you can see those nasty HTML character codes, making it clear you have real outer quotes, and HTML encoded inner quotes.

So the problem with trying to do the quoting yourself is Razor escapes these.

If you want complete control of quotes

Use Html.Raw to prevent quote escaping:

<td @Html.Raw( someBoolean ? "rel='tooltip' data-container='.drillDown a'" : "" )>

Renders as:

<td rel='tooltip' title='Drilldown' data-container='.drillDown a'>

The above is perfectly safe because I'm not outputting any HTML from a variable. The only variable involved is the ternary condition. However, beware that this last technique might expose you to certain security problems if building strings from user supplied data. E.g. if you built an attribute from data fields that originated from user supplied data, use of Html.Raw means that string could contain a premature ending of the attribute and tag, then begin a script tag that does something on behalf of the currently logged in user(possibly different than the logged in user). Maybe you have a page with a list of all users pictures and you are setting a tooltip to be the username of each person, and one users named himself '/><script>$.post('changepassword.php?password=123')</script> and now any other user who views this page has their password instantly changed to a password that the malicious user knows.

Wait for all promises to resolve

The accepted answer is correct. I would like to provide an example to elaborate it a bit to those who aren't familiar with promise.

Example:

In my example, I need to replace the src attributes of img tags with different mirror urls if available before rendering the content.

var img_tags = content.querySelectorAll('img');

function checkMirrorAvailability(url) {

    // blah blah 

    return promise;
}

function changeSrc(success, y, response) {
    if (success === true) {
        img_tags[y].setAttribute('src', response.mirror_url);
    } 
    else {
        console.log('No mirrors for: ' + img_tags[y].getAttribute('src'));
    }
}

var promise_array = [];

for (var y = 0; y < img_tags.length; y++) {
    var img_src = img_tags[y].getAttribute('src');

    promise_array.push(
        checkMirrorAvailability(img_src)
        .then(

            // a callback function only accept ONE argument. 
            // Here, we use  `.bind` to pass additional arguments to the
            // callback function (changeSrc).

            // successCallback
            changeSrc.bind(null, true, y),
            // errorCallback
            changeSrc.bind(null, false, y)
        )
    );
}

$q.all(promise_array)
.then(
    function() {
        console.log('all promises have returned with either success or failure!');
        render(content);
    }
    // We don't need an errorCallback function here, because above we handled
    // all errors.
);

Explanation:

From AngularJS docs:

The then method:

then(successCallback, errorCallback, notifyCallback) – regardless of when the promise was or will be resolved or rejected, then calls one of the success or error callbacks asynchronously as soon as the result is available. The callbacks are called with a single argument: the result or rejection reason.

$q.all(promises)

Combines multiple promises into a single promise that is resolved when all of the input promises are resolved.

The promises param can be an array of promises.

About bind(), More info here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Android: keeping a background service alive (preventing process death)

As Dave already pointed out, you could run your Service with foreground priority. But this practice should only be used when it's absolutely necessary, i.e. when it would cause a bad user experience if the Service got killed by Android. This is what the "foreground" really means: Your app is somehow in the foreground and the user would notice it immediately if it's killed (e.g. because it played a song or a video).

In most cases, requesting foreground priority for your Service is contraproductive!

Why is that? When Android decides to kill a Service, it does so because it's short of resources (usually RAM). Based on the different priority classes, Android decides which running processes, and this included services, to terminate in order to free resources. This is a healthy process that you want to happen so that the user has a smooth experience. If you request foreground priority, without a good reason, just to keep your service from being killed, it will most likely cause a bad user experience. Or can you guarantee that your service stays within a minimal resource consumption and has no memory leaks?1

Android provides sticky services to mark services that should be restarted after some grace period if they got killed. This restart usually happens within a few seconds.

Image you want to write an XMPP client for Android. Should you request foreground priority for the Service which contains your XMPP connection? Definitely no, there is absolutely no reason to do so. But you want to use START_STICKY as return flag for your service's onStartCommand method. So that your service is stopped when there is resource pressure and restarted once the situation is back to normal.

1: I am pretty sure that many Android apps have memory leaks. It something the casual (desktop) programmer doesn't care that much about.

Difference in Months between two dates in JavaScript

below logic will fetch difference in months

(endDate.getFullYear()*12+endDate.getMonth())-(startDate.getFullYear()*12+startDate.getMonth())

How to escape a while loop in C#

break or goto

while ( true ) {
  if ( conditional ) {
    break;
  }
  if ( other conditional ) {
    goto EndWhile;
  }
}
EndWhile:

Rename computer and join to domain in one step with PowerShell

$domain = "domain.local"
$password = "Passw@rd" | ConvertTo-SecureString -asPlainText -Force
$username = "$domain\Administrator"
$hostname=hostname
$credential = New-Object System.Management.Automation.PSCredential($username,$password)
Add-Computer -DomainName $domain -ComputerName $hostname -NewName alrootca -Credential $credential -Restart

Works for me ^^

How can I know which radio button is selected via jQuery?

If you want just the boolean value, i.e. if it's checked or not try this:

$("#Myradio").is(":checked")

Android ImageView Fixing Image Size

In your case you need to

  1. Fix the ImageView's size. You need to use dp unit so that it will look the same in all devices.
  2. Set android:scaleType to fitXY

Below is an example:

<ImageView
    android:id="@+id/photo"
    android:layout_width="200dp"
    android:layout_height="100dp"
    android:src="@drawable/iclauncher" 
    android:scaleType="fitXY"/>

For more information regarding ImageView scaleType please refer to the developer website.

Does C++ support 'finally' blocks? (And what's this 'RAII' I keep hearing about?)

why is it that even managed languages provide a finally-block despite resources being deallocated automatically by the garbage collector anyway?

Actually, languages based on Garbage collectors need "finally" more. A garbage collector does not destroy your objects in a timely manner, so it can not be relied upon to clean up non-memory related issues correctly.

In terms of dynamically-allocated data, many would argue that you should be using smart-pointers.

However...

RAII moves the responsibility of exception safety from the user of the object to the designer

Sadly this is its own downfall. Old C programming habits die hard. When you're using a library written in C or a very C style, RAII won't have been used. Short of re-writing the entire API front-end, that's just what you have to work with. Then the lack of "finally" really bites.

Converting a date in MySQL from string field

This:

STR_TO_DATE(t.datestring, '%d/%m/%Y')

...will convert the string into a datetime datatype. To be sure that it comes out in the format you desire, use DATE_FORMAT:

DATE_FORMAT(STR_TO_DATE(t.datestring, '%d/%m/%Y'), '%Y-%m-%d')

If you can't change the datatype on the original column, I suggest creating a view that uses the STR_TO_DATE call to convert the string to a DateTime data type.

IF-THEN-ELSE statements in postgresql

As stated in PostgreSQL docs here:

The SQL CASE expression is a generic conditional expression, similar to if/else statements in other programming languages.

Code snippet specifically answering your question:

SELECT field1, field2,
  CASE
    WHEN field1>0 THEN field2/field1
    ELSE 0
  END 
  AS field3
FROM test

are there dictionaries in javascript like python?

Have created a simple dictionary in JS here:

function JSdict() {
    this.Keys = [];
    this.Values = [];
}

// Check if dictionary extensions aren't implemented yet.
// Returns value of a key
if (!JSdict.prototype.getVal) {
    JSdict.prototype.getVal = function (key) {
        if (key == null) {
            return "Key cannot be null";
        }
        for (var i = 0; i < this.Keys.length; i++) {
            if (this.Keys[i] == key) {
                return this.Values[i];
            }
        }
        return "Key not found!";
    }
}


// Check if dictionary extensions aren't implemented yet.
// Updates value of a key
if (!JSdict.prototype.update) {
    JSdict.prototype.update = function (key, val) {
        if (key == null || val == null) {
            return "Key or Value cannot be null";
        }
        // Verify dict integrity before each operation
        if (keysLength != valsLength) {
            return "Dictionary inconsistent. Keys length don't match values!";
        }
        var keysLength = this.Keys.length;
        var valsLength = this.Values.length;
        var flag = false;
        for (var i = 0; i < keysLength; i++) {
            if (this.Keys[i] == key) {
                this.Values[i] = val;
                flag = true;
                break;
            }
        }
        if (!flag) {
            return "Key does not exist";
        }
    }
}



// Check if dictionary extensions aren't implemented yet.
// Adds a unique key value pair
if (!JSdict.prototype.add) {
    JSdict.prototype.add = function (key, val) {
        // Allow only strings or numbers as keys
        if (typeof (key) == "number" || typeof (key) == "string") {
            if (key == null || val == null) {
                return "Key or Value cannot be null";
            }
            if (keysLength != valsLength) {
                return "Dictionary inconsistent. Keys length don't match values!";
            }
            var keysLength = this.Keys.length;
            var valsLength = this.Values.length;
            for (var i = 0; i < keysLength; i++) {
                if (this.Keys[i] == key) {
                    return "Duplicate keys not allowed!";
                }
            }
            this.Keys.push(key);
            this.Values.push(val);
        }
        else {
            return "Only number or string can be key!";
        }
    }
}

// Check if dictionary extensions aren't implemented yet.
// Removes a key value pair
if (!JSdict.prototype.remove) {
    JSdict.prototype.remove = function (key) {
        if (key == null) {
            return "Key cannot be null";
        }
        if (keysLength != valsLength) {
            return "Dictionary inconsistent. Keys length don't match values!";
        }
        var keysLength = this.Keys.length;
        var valsLength = this.Values.length;
        var flag = false;
        for (var i = 0; i < keysLength; i++) {
            if (this.Keys[i] == key) {
                this.Keys.shift(key);
                this.Values.shift(this.Values[i]);
                flag = true;
                break;
            }
        }
        if (!flag) {
            return "Key does not exist";
        }
    }
}

The above implementation can now be used to simulate a dictionary as:

var dict = new JSdict();

dict.add(1, "one")

dict.add(1, "one more")
"Duplicate keys not allowed!"

dict.getVal(1)
"one"

dict.update(1, "onne")

dict.getVal(1)
"onne"

dict.remove(1)

dict.getVal(1)
"Key not found!"

This is just a basic simulation. It can be further optimized by implementing a better running time algorithm to work in atleast O(nlogn) time complexity or even less. Like merge/quick sort on arrays and then some B-search for lookups. I Didn't give a try or searched about mapping a hash function in JS.

Also, Key and Value for the JSdict obj can be turned into private variables to be sneaky.

Hope this helps!

EDIT >> After implementing the above, I personally used the JS objects as associative arrays that are available out-of-the-box.

However, I would like to make a special mention about two methods that actually proved helpful to make it a convenient hashtable experience.

Viz: dict.hasOwnProperty(key) and delete dict[key]

Read this post as a good resource on this implementation/usage. Dynamically creating keys in JavaScript associative array

THanks!

How can I pass request headers with jQuery's getJSON() method?

The $.getJSON() method is shorthand that does not let you specify advanced options like that. To do that, you need to use the full $.ajax() method.

Notice in the documentation at http://api.jquery.com/jQuery.getJSON/:

This is a shorthand Ajax function, which is equivalent to:

$.ajax({
  url: url,
  dataType: 'json',
  data: data,
  success: callback
});

So just use $.ajax() and provide all the extra parameters you need.

How can I undo a `git commit` locally and on a remote after `git push`

You can do an interactive rebase:

git rebase -i <commit>

This will bring up your default editor. Just delete the line containing the commit you want to remove to delete that commit.

You will, of course, need access to the remote repository to apply this change there too.

See this question: Git: removing selected commits from repository

Multiple conditions in an IF statement in Excel VBA

In VBA we can not use if jj = 5 or 6 then we must use if jj = 5 or jj = 6 then

maybe this:

If inputWks.Range("d9") > 0 And (inputWks.Range("d11") = "Restricted_Expenditure" Or inputWks.Range("d11") = "Unrestricted_Expenditure") Then

How can I get date and time formats based on Culture Info?

// Try this may help

DateTime myDate = new DateTime();
   string us = myDate.Now.Date.ToString("MM/dd/yyyy",new CultureInfo("en-US"));

or

 DateTime myDate = new DateTime();
        string us = myDate.Now.Date.ToString("dd/MM/yyyy",new CultureInfo("en-GB"));

Lint: How to ignore "<key> is not translated in <language>" errors?

The following worked for me.

  • Click on Windows
  • Click on preferences
  • Select android > Lint Error Checking.
  • Find and select the relevant Lint checking and
  • Set the severity to 'Ignore' (on bottom right)

Efficient way to return a std::vector in c++

   vector<string> func1() const
   {
      vector<string> parts;
      return vector<string>(parts.begin(),parts.end()) ;
   } 

PHP preg_replace special characters

$newstr = preg_replace('/[^a-zA-Z0-9\']/', '_', "There wouldn't be any");
$newstr = str_replace("'", '', $newstr);

I put them on two separate lines to make the code a little more clear.

Note: If you're looking for Unicode support, see Filip's answer below. It will match all characters that register as letters in addition to A-z.

Update multiple rows in same query using PostgreSQL

Yes, you can:

UPDATE foobar SET column_a = CASE
   WHEN column_b = '123' THEN 1
   WHEN column_b = '345' THEN 2
END
WHERE column_b IN ('123','345')

And working proof: http://sqlfiddle.com/#!2/97c7ea/1

Cannot drop database because it is currently in use

Go to available databases section and select master. Then Try DROP DATABASE the_DB_name.

How to get an MD5 checksum in PowerShell

Sample for right-click menu option as well:

[HKEY_CLASSES_ROOT\*\shell\SHA1 PS check\command]
@="C:\\Windows\\system32\\WindowsPowerShell\\v1.0\\powershell.exe -NoExit -Command Get-FileHash -Algorithm SHA1 '%1'"

Converting integer to digit list

There are already great methods already mentioned on this page, however it does seem a little obscure as to which to use. So I have added some mesurements so you can more easily decide for yourself:


A large number has been used (for overhead) 1111111111111122222222222222222333333333333333333333

Using map(int, str(num)):

import timeit

def method():
    num = 1111111111111122222222222222222333333333333333333333
    return map(int, str(num))

print(timeit.timeit("method()", setup="from __main__ import method", number=10000)

Output: 0.018631496999999997

Using list comprehension:

import timeit

def method():
    num = 1111111111111122222222222222222333333333333333333333
    return [int(x) for x in str(num)]

print(timeit.timeit("method()", setup="from __main__ import method", number=10000))

Output: 0.28403817900000006

Code taken from this answer

The results show that the first method involving inbuilt methods is much faster than list comprehension.

The "mathematical way":

import timeit

def method():
    q = 1111111111111122222222222222222333333333333333333333
    ret = []
    while q != 0:
        q, r = divmod(q, 10) # Divide by 10, see the remainder
        ret.insert(0, r) # The remainder is the first to the right digit
    return ret

print(timeit.timeit("method()", setup="from __main__ import method", number=10000))

Output: 0.38133582499999996

Code taken from this answer

The list(str(123)) method (does not provide the right output):

import timeit

def method():
    return list(str(1111111111111122222222222222222333333333333333333333))
    
print(timeit.timeit("method()", setup="from __main__ import method", number=10000))

Output: 0.028560138000000013

Code taken from this answer

The answer by Duberly González Molinari:

import timeit

def method():
    n = 1111111111111122222222222222222333333333333333333333
    l = []
    while n != 0:
        l = [n % 10] + l
        n = n // 10
    return l

print(timeit.timeit("method()", setup="from __main__ import method", number=10000))

Output: 0.37039988200000007

Code taken from this answer

Remarks:

In all cases the map(int, str(num)) is the fastest method (and is therefore probably the best method to use). List comprehension is the second fastest (but the method using map(int, str(num)) is probably the most desirable of the two.

Those that reinvent the wheel are interesting but are probably not so desirable in real use.

css display table cell requires percentage width

You just need to add 'table-layout: fixed;'

.table {
   display: table;
   height: 100px;
   width: 100%;
   table-layout: fixed;
}

http://www.w3schools.com/cssref/pr_tab_table-layout.asp

Closing a Userform with Unload Me doesn't work

It should also be noted that if you have buttons grouped together on your user form that it can link it to a different button in the group despite the one you intended being clicked.

How do I make CMake output into a 'bin' dir?

As to me I am using cmake 3.5, the below(set variable) does not work:

set(
      ARCHIVE_OUTPUT_DIRECTORY "/home/xy/cmake_practice/lib/"
      LIBRARY_OUTPUT_DIRECTORY "/home/xy/cmake_practice/lib/"
      RUNTIME_OUTPUT_DIRECTORY "/home/xy/cmake_practice/bin/"
)

but this works(set set_target_properties):

set_target_properties(demo5
    PROPERTIES
    ARCHIVE_OUTPUT_DIRECTORY "/home/xy/cmake_practice/lib/"
    LIBRARY_OUTPUT_DIRECTORY "/home/xy/cmake_practice/lib/"
    RUNTIME_OUTPUT_DIRECTORY "/home/xy/cmake_practice/bin/"
)

What's the best way to detect a 'touch screen' device using JavaScript?

Although it's only in alpha, the jquery mobile framework is worth checking out. It will normalize these types of events across mobile browsers. Perhaps see what they're doing. I'm assuming jquery-mobile.js is something different than this framework.

Split varchar into separate columns in Oracle

Simple way is to convert into column

SELECT COLUMN_VALUE FROM TABLE (SPLIT ('19869,19572,19223,18898,10155,'))

CREATE TYPE split_tbl as TABLE OF VARCHAR2(32767);

CREATE OR REPLACE FUNCTION split (p_list VARCHAR2, p_del VARCHAR2 := ',')
   RETURN split_tbl
   PIPELINED IS
   l_idx PLS_INTEGER;
   l_list VARCHAR2 (32767) := p_list;
   l_value VARCHAR2 (32767);
BEGIN
   LOOP
      l_idx := INSTR (l_list, p_del);

      IF l_idx > 0 THEN
         PIPE ROW (SUBSTR (l_list, 1, l_idx - 1));
         l_list := SUBSTR (l_list, l_idx + LENGTH (p_del));
      ELSE
         PIPE ROW (l_list);
         EXIT;
      END IF;
   END LOOP;

   RETURN;
END split;

How to save MySQL query output to excel or .txt file?

From Save MySQL query results into a text or CSV file:

MySQL provides an easy mechanism for writing the results of a select statement into a text file on the server. Using extended options of the INTO OUTFILE nomenclature, it is possible to create a comma separated value (CSV) which can be imported into a spreadsheet application such as OpenOffice or Excel or any other application which accepts data in CSV format.

Given a query such as

SELECT order_id,product_name,qty FROM orders

which returns three columns of data, the results can be placed into the file /tmp/orders.txt using the query:

SELECT order_id,product_name,qty FROM orders
INTO OUTFILE '/tmp/orders.txt'

This will create a tab-separated file, each row on its own line. To alter this behavior, it is possible to add modifiers to the query:

SELECT order_id,product_name,qty FROM orders
INTO OUTFILE '/tmp/orders.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'

In this example, each field will be enclosed in double quotes, the fields will be separated by commas, and each row will be output on a new line separated by a newline (\n). Sample output of this command would look like:

"1","Tech-Recipes sock puppet","14.95" "2","Tech-Recipes chef's hat","18.95"

Keep in mind that the output file must not already exist and that the user MySQL is running as has write permissions to the directory MySQL is attempting to write the file to.

Syntax

   SELECT Your_Column_Name
    FROM Your_Table_Name
    INTO OUTFILE 'Filename.csv'
    FIELDS TERMINATED BY ','
    ENCLOSED BY '"'
    LINES TERMINATED BY '\n'

Or you could try to grab the output via the client:

You could try executing the query from the your local client and redirect the output to a local file destination:

mysql -user -pass -e "select cols from table where cols not null" > /tmp/output

Hint: If you don't specify an absoulte path but use something like INTO OUTFILE 'output.csv' or INTO OUTFILE './output.csv', it will store the output file to the directory specified by show variables like 'datadir';.

Does VBScript have a substring() function?

Yes, Mid.

Dim sub_str
sub_str = Mid(source_str, 10, 5)

The first parameter is the source string, the second is the start index, and the third is the length.

@bobobobo: Note that VBScript strings are 1-based, not 0-based. Passing 0 as an argument to Mid results in "invalid procedure call or argument Mid".

JavaScript Nested function

Functions are another type of variable in JavaScript (with some nuances of course). Creating a function within another function changes the scope of the function in the same way it would change the scope of a variable. This is especially important for use with closures to reduce total global namespace pollution.

The functions defined within another function won't be accessible outside the function unless they have been attached to an object that is accessible outside the function:

function foo(doBar)
{
  function bar()
  {
    console.log( 'bar' );
  }

  function baz()
  {
    console.log( 'baz' );
  }

  window.baz = baz;
  if ( doBar ) bar();
}

In this example, the baz function will be available for use after the foo function has been run, as it's overridden window.baz. The bar function will not be available to any context other than scopes contained within the foo function.

as a different example:

function Fizz(qux)
{
  this.buzz = function(){
    console.log( qux );
  };
}

The Fizz function is designed as a constructor so that, when run, it assigns a buzz function to the newly created object.

How can I make a countdown with NSTimer?

Variable for your timer

var timer = 60

NSTimer with 1.0 as interval

var clock = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: "countdown", userInfo: nil, repeats: true)

Here you can decrease the timer

func countdown() {
    timer--
}

Set style for TextView programmatically

You can set the style in the constructor (but styles can not be dynamically changed/set).

View(Context, AttributeSet, int) (the int is an attribute in the current theme that contains a reference to a style)

Answer from Romain Guy

reference

Setting selection to Nothing when programming Excel

None of the many answers with Application.CutCopyMode or .Select worked for me.

But I did find a solution not posted here, which worked fantastically for me!

From StackExchange SuperUser: Excel VBA “Unselect” wanted

If you are really wanting 'nothing selected`, you can use VBA to protect the sheet at the end of your code execution, which will cause nothing to be selected. You can either add this to a macro or put it into your VBA directly.

Sub NoSelect()
   With ActiveSheet
   .EnableSelection = xlNoSelection
   .Protect
   End With
End Sub

As soon as the sheet is unprotected, the cursor will activate a cell.

Hope this helps someone with the same problem!

How to download all files (but not HTML) from a website using wget?

You may try:

wget --user-agent=Mozilla --content-disposition --mirror --convert-links -E -K -p http://example.com/

Also you can add:

-A pdf,ps,djvu,tex,doc,docx,xls,xlsx,gz,ppt,mp4,avi,zip,rar

to accept the specific extensions, or to reject only specific extensions:

-R html,htm,asp,php

or to exclude the specific areas:

-X "search*,forum*"

If the files are ignored for robots (e.g. search engines), you've to add also: -e robots=off

Git merge without auto commit

When there is one commit only in the branch, I usually do

git merge branch_name --ff

Javascript Image Resize

Tried the following code, worked OK on IE6 on WinXP Pro SP3.

function Resize(imgId)
{
  var img = document.getElementById(imgId);
  var w = img.width, h = img.height;
  w /= 2; h /= 2;
  img.width = w; img.height = h;
}

Also OK in FF3 and Opera 9.26.

For Loop on Lua

names = {'John', 'Joe', 'Steve'}
for names = 1, 3 do
  print (names)
end
  1. You're deleting your table and replacing it with an int
  2. You aren't pulling a value from the table

Try:

names = {'John','Joe','Steve'}
for i = 1,3 do
    print(names[i])
end

How to Check whether Session is Expired or not in asp.net

I prefer not to check session variable in code instead use FormAuthentication. They have inbuilt functionlity to redirect to given LoginPage specified in web.config.

However if you want to explicitly check the session you can check for NULL value for any of the variable you created in session earlier as Pranay answered.

You can create Login.aspx page and write your message there , when session expires FormAuthentication automatically redirect to loginUrl given in FormAuthentication section

<authentication mode="Forms">
  <forms loginUrl="Login.aspx" protection="All" timeout="30">
  </forms>
</authentication>

The thing is that you can't give seperate page for Login and SessionExpire , so you have to show/hide some section on Login.aspx to act it both ways.

There is another way to redirect to sessionexpire page after timeout without changing formauthentication->loginurl , see the below link for this : http://www.schnieds.com/2009/07/aspnet-session-expiration-redirect.html

Why doesn't JavaScript support multithreading?

Node.js 10.5+ supports worker threads as experimental feature (you can use it with --experimental-worker flag enabled): https://nodejs.org/api/worker_threads.html

So, the rule is:

  • if you need to do I/O bound ops, then use the internal mechanism (aka callback/promise/async-await)
  • if you need to do CPU bound ops, then use worker threads.

Worker threads are intended to be long-living threads, meaning you spawn a background thread and then you communicate with it via message passing.

Otherwise, if you need to execute a heavy CPU load with an anonymous function, then you can go with https://github.com/wilk/microjob, a tiny library built around worker threads.

how to read xml file from url using php

It is working for me. I think you probably need to use urlencode() on each of the components of $map_url.

check output from CalledProcessError

According to the Python os module documentation os.popen has been deprecated since Python 2.6.

I think the solution for modern Python is to use check_output() from the subprocess module.

From the subprocess Python documentation:

subprocess.check_output(args, *, stdin=None, stderr=None, shell=False, universal_newlines=False) Run command with arguments and return its output as a byte string.

If the return code was non-zero it raises a CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute and any output in the output attribute.

If you run through the following code in Python 2.7 (or later):

import subprocess

try:
    print subprocess.check_output(["ping", "-n", "2", "-w", "2", "1.1.1.1"])
except subprocess.CalledProcessError, e:
    print "Ping stdout output:\n", e.output

You should see an output that looks something like this:

Ping stdout output:

Pinging 1.1.1.1 with 32 bytes of data:
Request timed out.
Request timed out.

Ping statistics for 1.1.1.1:
Packets: Sent = 2, Received = 0, Lost = 2 (100% loss),

The e.output string can be parsed to suit the OPs needs.

If you want the returncode or other attributes, they are in CalledProccessError as can be seen by stepping through with pdb

(Pdb)!dir(e)   

['__class__', '__delattr__', '__dict__', '__doc__', '__format__',
 '__getattribute__', '__getitem__', '__getslice__', '__hash__', '__init__',
 '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__',
 '__setattr__', '__setstate__', '__sizeof__', '__str__', '__subclasshook__', 
 '__unicode__', '__weakref__', 'args', 'cmd', 'message', 'output', 'returncode']

JQuery Bootstrap Multiselect plugin - Set a value as selected in the multiselect dropdown

//Do it simple

var data="1,2,3,4";

//Make an array

var dataarray=data.split(",");

// Set the value

$("#multiselectbox").val(dataarray);

// Then refresh

$("#multiselectbox").multiselect("refresh");

CASE WHEN statement for ORDER BY clause

Another simple example from here..

SELECT * FROM dbo.Employee
ORDER BY 
 CASE WHEN Gender='Male' THEN EmployeeName END Desc,
 CASE WHEN Gender='Female' THEN Country END ASC

key_load_public: invalid format

If you're using Windows 10 with the built-in SSH, as of August 2020 it only supports ed25519 keys. You'll get the key_load_public: invalid format error if you use e.g. an RSA key.

As per this GitHub issue it should be fixed via Windows Update some time in 2020. So one solution is to just wait for the update to ship.

If you can't wait, a workaround is to generate a new ed25519 key, which is good advice anyway.

> ssh-keygen -o -a 100 -t ed25519

You can use it with e.g. github, but some older systems might not support this newer format.

After generating your key, if you're using either of the below features, don't forget to update them!

  1. ~\.ssh\config might still point to the old key.
  2. Add the new key to ssh-agent via the ssh-add command

PHP Multiple Checkbox Array

Also remember you can include custom indices to the array sent to the server like this

<form method='post' id='userform' action='thisform.php'>
<tr>
    <td>Trouble Type</td>
    <td>
    <input type='checkbox' name='checkboxvar[4]' value='Option One'>4<br>
    <input type='checkbox' name='checkboxvar[6]' value='Option Two'>6<br>
    <input type='checkbox' name='checkboxvar[9]' value='Option Three'>9
    </td>
</tr>
<input type='submit' class='buttons'>
</form>

This is particularly useful when you want to use the id of individual objects in a server array accounts (for instance) to send data back to the server and recognize same at server

<form method='post' id='userform' action='thisform.php'>
<tr>
    <td>Trouble Type</td>
    <td>
    <?php foreach($accounts as $account) { ?>
        <input type='checkbox' name='accounts[<?php echo $account->id ?>]' value='<?php echo $account->name ?>'>
        <?php echo $account->name ?>
        <br>
    <?php } ?>
    </td>
</tr>
<input type='submit' class='buttons'>
</form>

<?php 
if (isset($_POST['accounts'])) 
{
    print_r($_POST['accounts']); 
}
?>

Custom CSS for <audio> tag?

There is not currently any way to style HTML5 <audio> players using CSS. Instead, you can leave off the control attribute, and implement your own controls using Javascript. If you don't want to implement them all on your own, I'd recommend using an existing themeable HTML5 audio player, such as jPlayer.

How do I pick randomly from an array?

class String

  def black
    return "\e[30m#{self}\e[0m"
  end

  def red
    return "\e[31m#{self}\e[0m"
  end

  def light_green
    return "\e[32m#{self}\e[0m"
  end

  def purple
    return "\e[35m#{self}\e[0m"
  end

  def blue_dark
    return "\e[34m#{self}\e[0m"
  end

  def blue_light
    return "\e[36m#{self}\e[0m"
  end

  def white
    return "\e[37m#{self}\e[0m"
  end


  def randColor
    array_color = [
      "\e[30m#{self}\e[0m",
      "\e[31m#{self}\e[0m",
      "\e[32m#{self}\e[0m",
      "\e[35m#{self}\e[0m",
      "\e[34m#{self}\e[0m",
      "\e[36m#{self}\e[0m",
      "\e[37m#{self}\e[0m" ]

      return array_color[rand(0..array_color.size)]
  end


end
puts "black".black
puts "red".red
puts "light_green".light_green
puts "purple".purple
puts "dark blue".blue_dark
puts "light blue".blue_light
puts "white".white
puts "random color".randColor

ValueError when checking if variable is None or numpy.array

If you are trying to do something very similar: a is not None, the same issue comes up. That is, Numpy complains that one must use a.any or a.all.

A workaround is to do:

if not (a is None):
    pass

Not too pretty, but it does the job.

Initialising a multidimensional array in Java

Try replacing the appropriate lines with:

myStringArray[0][x-1] = "a string";
myStringArray[0][y-1] = "another string";

Your code is incorrect because the sub-arrays have a length of y, and indexing starts at 0. So setting to myStringArray[0][y] or myStringArray[0][x] will fail because the indices x and y are out of bounds.

String[][] myStringArray = new String [x][y]; is the correct way to initialise a rectangular multidimensional array. If you want it to be jagged (each sub-array potentially has a different length) then you can use code similar to this answer. Note however that John's assertion that you have to create the sub-arrays manually is incorrect in the case where you want a perfectly rectangular multidimensional array.

Convert byte to string in Java

If it's a single byte, just cast the byte to a char and it should work out to be fine i.e. give a char entity corresponding to the codepoint value of the given byte. If not, use the String constructor as mentioned elsewhere.

char ch = (char)0x63;
System.out.println(ch);

CSS values using HTML5 data attribute

There is, indeed, prevision for such feature, look http://www.w3.org/TR/css3-values/#attr-notation

This fiddle should work like what you need, but will not for now.

Unfortunately, it's still a draft, and isn't fully implemented on major browsers.

It does work for content on pseudo-elements, though.

how to overwrite css style

Just add

.flex-control-thumbs li {
width: auto; 
}

Docker: Multiple Dockerfiles in project

Add an abstraction layer, for example, a YAML file like in this project https://github.com/larytet/dockerfile-generator which looks like

centos7:
    base: centos:centos7
    packager: rpm
    install:
      - $build_essential_centos 
      - rpm-build
    run:
      - $get_release
    env:
      - $environment_vars

A short Python script/make can generate all Dockerfiles from the configuration file.

How to retrieve the first word of the output of a command in bash?

echo "word1 word2 word3" | { read first rest ; echo $first ; }

This has the advantage that is not using external commands and leaves the $1, $2, etc. variables intact.

How to add a new line in textarea element?

My .replace()function using the patterns described on the other answers did not work. The pattern that worked for my case was:

var str = "Test\n\n\Test\n\Test";
str.replace(/\r\n|\r|\n/g,'&#13;&#10;');

// str: "Test&#13;&#10;&#13;&#10;Test&#13;&#10;Test"

You don't have permission to access / on this server

Fist check that apache is running. service httpd restart for restarting

CentOS 6 comes with SELinux activated, so, either change the policy or disabled it by editing /etc/sysconfig/selinux setting SELINUX=disabled. Then restart

Then check locally (from centos) if apache is working.

How to compare strings in an "if" statement?

You can't compare array of characters using == operator. You have to use string compare functions. Take a look at Strings (c-faq).

The standard library's strcmp function compares two strings, and returns 0 if they are identical, or a negative number if the first string is alphabetically "less than" the second string, or a positive number if the first string is "greater."

javax.persistence.PersistenceException: No Persistence provider for EntityManager named customerManager

I was facing the same issue. I realised that I was using the Wrong provider class in persistence.xml

For Hibernate it should be

<provider>org.hibernate.ejb.HibernatePersistence</provider>

And for EclipseLink it should be

<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

What methods of ‘clearfix’ can I use?

The overflow property can be used to clear floats with no additional mark-up:

.container { overflow: hidden; }

This works for all browsers except IE6, where all you need to do is enable hasLayout (zoom being my preferred method):

.container { zoom: 1; }

http://www.quirksmode.org/css/clearing.html

How can I create a copy of an object in Python?

How can I create a copy of an object in Python?

So, if I change values of the fields of the new object, the old object should not be affected by that.

You mean a mutable object then.

In Python 3, lists get a copy method (in 2, you'd use a slice to make a copy):

>>> a_list = list('abc')
>>> a_copy_of_a_list = a_list.copy()
>>> a_copy_of_a_list is a_list
False
>>> a_copy_of_a_list == a_list
True

Shallow Copies

Shallow copies are just copies of the outermost container.

list.copy is a shallow copy:

>>> list_of_dict_of_set = [{'foo': set('abc')}]
>>> lodos_copy = list_of_dict_of_set.copy()
>>> lodos_copy[0]['foo'].pop()
'c'
>>> lodos_copy
[{'foo': {'b', 'a'}}]
>>> list_of_dict_of_set
[{'foo': {'b', 'a'}}]

You don't get a copy of the interior objects. They're the same object - so when they're mutated, the change shows up in both containers.

Deep copies

Deep copies are recursive copies of each interior object.

>>> lodos_deep_copy = copy.deepcopy(list_of_dict_of_set)
>>> lodos_deep_copy[0]['foo'].add('c')
>>> lodos_deep_copy
[{'foo': {'c', 'b', 'a'}}]
>>> list_of_dict_of_set
[{'foo': {'b', 'a'}}]

Changes are not reflected in the original, only in the copy.

Immutable objects

Immutable objects do not usually need to be copied. In fact, if you try to, Python will just give you the original object:

>>> a_tuple = tuple('abc')
>>> tuple_copy_attempt = a_tuple.copy()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'copy'

Tuples don't even have a copy method, so let's try it with a slice:

>>> tuple_copy_attempt = a_tuple[:]

But we see it's the same object:

>>> tuple_copy_attempt is a_tuple
True

Similarly for strings:

>>> s = 'abc'
>>> s0 = s[:]
>>> s == s0
True
>>> s is s0
True

and for frozensets, even though they have a copy method:

>>> a_frozenset = frozenset('abc')
>>> frozenset_copy_attempt = a_frozenset.copy()
>>> frozenset_copy_attempt is a_frozenset
True

When to copy immutable objects

Immutable objects should be copied if you need a mutable interior object copied.

>>> tuple_of_list = [],
>>> copy_of_tuple_of_list = tuple_of_list[:]
>>> copy_of_tuple_of_list[0].append('a')
>>> copy_of_tuple_of_list
(['a'],)
>>> tuple_of_list
(['a'],)
>>> deepcopy_of_tuple_of_list = copy.deepcopy(tuple_of_list)
>>> deepcopy_of_tuple_of_list[0].append('b')
>>> deepcopy_of_tuple_of_list
(['a', 'b'],)
>>> tuple_of_list
(['a'],)

As we can see, when the interior object of the copy is mutated, the original does not change.

Custom Objects

Custom objects usually store data in a __dict__ attribute or in __slots__ (a tuple-like memory structure.)

To make a copyable object, define __copy__ (for shallow copies) and/or __deepcopy__ (for deep copies).

from copy import copy, deepcopy

class Copyable:
    __slots__ = 'a', '__dict__'
    def __init__(self, a, b):
        self.a, self.b = a, b
    def __copy__(self):
        return type(self)(self.a, self.b)
    def __deepcopy__(self, memo): # memo is a dict of id's to copies
        id_self = id(self)        # memoization avoids unnecesary recursion
        _copy = memo.get(id_self)
        if _copy is None:
            _copy = type(self)(
                deepcopy(self.a, memo), 
                deepcopy(self.b, memo))
            memo[id_self] = _copy 
        return _copy

Note that deepcopy keeps a memoization dictionary of id(original) (or identity numbers) to copies. To enjoy good behavior with recursive data structures, make sure you haven't already made a copy, and if you have, return that.

So let's make an object:

>>> c1 = Copyable(1, [2])

And copy makes a shallow copy:

>>> c2 = copy(c1)
>>> c1 is c2
False
>>> c2.b.append(3)
>>> c1.b
[2, 3]

And deepcopy now makes a deep copy:

>>> c3 = deepcopy(c1)
>>> c3.b.append(4)
>>> c1.b
[2, 3]

Unable to generate an explicit migration in entity framework

1. Connection String / Connection Permissions

Check the connection string again.

Make sure the user you are connecting with still has permission to read from [__MigrationHistory] and has permission to edit the schema.

You can also try changing the connection string in the App or Web config file to use Integrated Security (Windows Auth) to run the add-migration command as yourself.

For example:

connectionString="data source=server;initial catalog=db;persist security info=True;Integrated Security=SSPI;" 

This connection string would go in the App.config file of the project where the DbContext is located.

2. StartUp Project

You can specify the StartUp project on the command line or you can right click the project with the DbContext, Configuration and Migrations folder and select Set as StartUp project. I'm serious, this can actually help.

enter image description here

converting multiple columns from character to numeric format in r

I think I figured it out. Here's what I did (perhaps not the most elegant solution - suggestions on how to imp[rove this are very much welcome)

#names of columns in data frame
cols <- names(DF)
# character variables
cols.char <- c("fx_code","date")
#numeric variables
cols.num <- cols[!cols %in% cols.char]

DF.char <- DF[cols.char]
DF.num <- as.data.frame(lapply(DF[cols.num],as.numeric))
DF2 <- cbind(DF.char, DF.num)

how to POST/Submit an Input Checkbox that is disabled?

If you're happy using JQuery then remove the disabled attribute when submitting the form:

$("form").submit(function() {
    $("input").removeAttr("disabled");
});

Reflection: How to Invoke Method with parameters

 Assembly assembly = Assembly.LoadFile(@"....bin\Debug\TestCases.dll");
       //get all types
        var testTypes = from t in assembly.GetTypes()
                        let attributes = t.GetCustomAttributes(typeof(NUnit.Framework.TestFixtureAttribute), true)
                        where attributes != null && attributes.Length > 0
                        orderby t.Name
                        select t;

        foreach (var type in testTypes)
        {
            //get test method in types.
            var testMethods = from m in type.GetMethods()
                              let attributes = m.GetCustomAttributes(typeof(NUnit.Framework.TestAttribute), true)
                              where attributes != null && attributes.Length > 0
                              orderby m.Name
                              select m;

            foreach (var method in testMethods)
            {
                MethodInfo methodInfo = type.GetMethod(method.Name);

                if (methodInfo != null)
                {
                    object result = null;
                    ParameterInfo[] parameters = methodInfo.GetParameters();
                    object classInstance = Activator.CreateInstance(type, null);

                    if (parameters.Length == 0)
                    {
                        // This works fine
                        result = methodInfo.Invoke(classInstance, null);
                    }
                    else
                    {
                        object[] parametersArray = new object[] { "Hello" };

                        // The invoke does NOT work;
                        // it throws "Object does not match target type"             
                        result = methodInfo.Invoke(classInstance, parametersArray);
                    }
                }

            }
        }

iterating quickly through list of tuples

The code can be cleaned up, but if you are using a list to store your tuples, any such lookup will be O(N).

If lookup speed is important, you should use a dict to store your tuples. The key should be the 0th element of your tuples, since that's what you're searching on. You can easily create a dict from your list:

my_dict = dict(my_list)

Then, (VALUE, my_dict[VALUE]) will give you your matching tuple (assuming VALUE exists).

How to cherry pick a range of commits and merge into another branch?

When it comes to a range of commits, cherry-picking is was not practical.

As mentioned below by Keith Kim, Git 1.7.2+ introduced the ability to cherry-pick a range of commits (but you still need to be aware of the consequence of cherry-picking for future merge)

git cherry-pick" learned to pick a range of commits
(e.g. "cherry-pick A..B" and "cherry-pick --stdin"), so did "git revert"; these do not support the nicer sequencing control "rebase [-i]" has, though.

damian comments and warns us:

In the "cherry-pick A..B" form, A should be older than B.
If they're the wrong order the command will silently fail.

If you want to pick the range B through D (including B) that would be B^..D (instead of B..D).
See "Git create branch from range of previous commits?" as an illustration.

As Jubobs mentions in the comments:

This assumes that B is not a root commit; you'll get an "unknown revision" error otherwise.

Note: as of Git 2.9.x/2.10 (Q3 2016), you can cherry-pick a range of commit directly on an orphan branch (empty head): see "How to make existing branch an orphan in git".


Original answer (January 2010)

A rebase --onto would be better, where you replay the given range of commit on top of your integration branch, as Charles Bailey described here.
(also, look for "Here is how you would transplant a topic branch based on one branch to another" in the git rebase man page, to see a practical example of git rebase --onto)

If your current branch is integration:

# Checkout a new temporary branch at the current location
git checkout -b tmp

# Move the integration branch to the head of the new patchset
git branch -f integration last_SHA-1_of_working_branch_range

# Rebase the patchset onto tmp, the old location of integration
git rebase --onto tmp first_SHA-1_of_working_branch_range~1 integration

That will replay everything between:

  • after the parent of first_SHA-1_of_working_branch_range (hence the ~1): the first commit you want to replay
  • up to "integration" (which points to the last commit you want to replay, from the working branch)

to "tmp" (which points to where integration was pointing before)

If there is any conflict when one of those commits is replayed:

  • either solve it and run "git rebase --continue".
  • or skip this patch, and instead run "git rebase --skip"
  • or cancel the all thing with a "git rebase --abort" (and put back the integration branch on the tmp branch)

After that rebase --onto, integration will be back at the last commit of the integration branch (that is "tmp" branch + all the replayed commits)

With cherry-picking or rebase --onto, do not forget it has consequences on subsequent merges, as described here.


A pure "cherry-pick" solution is discussed here, and would involve something like:

If you want to use a patch approach then "git format-patch|git am" and "git cherry" are your options.
Currently, git cherry-pick accepts only a single commit, but if you want to pick the range B through D that would be B^..D in git lingo, so

git rev-list --reverse --topo-order B^..D | while read rev 
do 
  git cherry-pick $rev || break 
done 

But anyway, when you need to "replay" a range of commits, the word "replay" should push you to use the "rebase" feature of Git.

How to fix Error: "Could not find schema information for the attribute/element" by creating schema

UPDATE Sept 2015
This answer continues to get upvotes, so I'm going to leave it here since it seems to be helpful to some people, but please check out the other answers from @reexmonkey and @Pressacco first. They may provide better results.

ORIGINAL ANSWER
Give this a shot:

  1. In Visual Studio, open your app.config or web.config file.
  2. Go to the "XML" menu and select "Create Schema". This action should create a new file called "app.xsd" or "web.xsd".
  3. Save that file to your disk.
  4. Go back to your app.config or web.config and in the edit window, right click and select properties. From there, make sure the xsd you just generated is referenced in the Schemas property. If it's not there then add it.

That should cause those messages to disappear.

I saved my web.xsd in the root of my web folder (which might not be the best place for it, but just for demonstration purposes) and my Schemas property looks like this:

"C:\Program Files (x86)\Microsoft Visual Studio 10.0\xml\Schemas\DotNetConfig.xsd" "Web.xsd"

Convert a list of characters into a string

besides str.join which is the most natural way, a possibility is to use io.StringIO and abusing writelines to write all elements in one go:

import io

a = ['a','b','c','d']

out = io.StringIO()
out.writelines(a)
print(out.getvalue())

prints:

abcd

When using this approach with a generator function or an iterable which isn't a tuple or a list, it saves the temporary list creation that join does to allocate the right size in one go (and a list of 1-character strings is very expensive memory-wise).

If you're low in memory and you have a lazily-evaluated object as input, this approach is the best solution.

How can I print using JQuery

function printResult() {
    var DocumentContainer = document.getElementById('your_div_id');
    var WindowObject = window.open('', "PrintWindow", "width=750,height=650,top=50,left=50,toolbars=no,scrollbars=yes,status=no,resizable=yes");
    WindowObject.document.writeln(DocumentContainer.innerHTML);
    WindowObject.document.close();
    WindowObject.focus();
    WindowObject.print();
    WindowObject.close();
}

How to clear memory to prevent "out of memory error" in excel vba?

Answer is you can't explicitly but you should be freeing memory in your routines.

Some tips though to help memory

  • Make sure you set object to null before exiting your routine.
  • Ensure you call Close on objects if they require it.
  • Don't use global variables unless absolutely necessary

I would recommend checking the memory usage after performing the routine again and again you may have a memory leak.

jQuery append() - return appended elements

var newElementsAppended = $(newHtml).appendTo("#myDiv");
newElementsAppended.effects("highlight", {}, 2000);

In SQL Server, how to create while loop in select

No functions, no cursors. Try this

with cte as(
select CHAR(65) chr, 65 i 
union all
select CHAR(i+1) chr, i=i+1 from cte
where CHAR(i) <'Z'
)
select * from(
SELECT id, Case when LEN(data)>len(REPLACE(data, chr,'')) then chr+chr end data 
FROM table1, cte) x
where Data is not null

clear table jquery

<table id="myTable" class="table" cellspacing="0" width="100%">
    <thead>
        <tr>
            <th>Header 1</th>
            <th>Header 2</th>
            <th>Header 3</th>
        </tr>
    </thead>
    <tbody id="tblBody">

    </tbody>
</table>

And Remove:

$("#tblBody").empty();

IsNull function in DB2 SQL?

COALESCE function same ISNULL function Note. you must use COALESCE function with same data type of column that you check is null.

Pretty printing XML in Python

XML pretty print for python looks pretty good for this task. (Appropriately named, too.)

An alternative is to use pyXML, which has a PrettyPrint function.

Why do this() and super() have to be the first statement in a constructor?

Tldr:

The other answers have tackled the "why" of the question. I'll provide a hack around this limitation:

The basic idea is to hijack the super statement with your embedded statements. This can be done by disguising your statements as expressions.

Tsdr:

Consider we want to do Statement1() to Statement9() before we call super():

public class Child extends Parent {
    public Child(T1 _1, T2 _2, T3 _3) {
        Statement_1();
        Statement_2();
        Statement_3(); // and etc...
        Statement_9();
        super(_1, _2, _3); // compiler rejects because this is not the first line
    }
}

The compiler will of course reject our code. So instead, we can do this:

// This compiles fine:

public class Child extends Parent {
    public Child(T1 _1, T2 _2, T3 _3) {
        super(F(_1), _2, _3);
    }

    public static T1 F(T1 _1) {
        Statement_1();
        Statement_2();
        Statement_3(); // and etc...
        Statement_9();
        return _1;
    }
}

The only limitation is that the parent class must have a constructor which takes in at least one argument so that we can sneak in our statement as an expression.

Here is a more elaborate example:

public class Child extends Parent {
    public Child(int i, String s, T1 t1) {
        i = i * 10 - 123;
        if (s.length() > i) {
            s = "This is substr s: " + s.substring(0, 5);
        } else {
            s = "Asdfg";
        }
        t1.Set(i);
        T2 t2 = t1.Get();
        t2.F();
        Object obj = Static_Class.A_Static_Method(i, s, t1);
        super(obj, i, "some argument", s, t1, t2); // compiler rejects because this is not the first line
    }
}

Reworked into:

// This compiles fine:

public class Child extends Parent {
    public Child(int i, String s, T1 t1) {
        super(Arg1(i, s, t1), Arg2(i), "some argument", Arg4(i, s), t1, Arg6(i, t1));
    }

    private static Object Arg1(int i, String s, T1 t1) {
        i = Arg2(i);
        s = Arg4(s);
        return Static_Class.A_Static_Method(i, s, t1);
    }

    private static int Arg2(int i) {
        i = i * 10 - 123;
        return i;
    }

    private static String Arg4(int i, String s) {
        i = Arg2(i);
        if (s.length() > i) {
            s = "This is sub s: " + s.substring(0, 5);
        } else {
            s = "Asdfg";
        }
        return s;
    }

    private static T2 Arg6(int i, T1 t1) {
        i = Arg2(i);
        t1.Set(i);
        T2 t2 = t1.Get();
        t2.F();
        return t2;
    }
}

In fact, compilers could have automated this process for us. They'd just chosen not to.

How to check if a list is empty in Python?

Empty lists evaluate to False in boolean contexts (such as if some_list:).

How can I get a list of all open named pipes in Windows?

Try the following instead:

String[] listOfPipes = System.IO.Directory.GetFiles(@"\\.\pipe\");

How should I log while using multiprocessing in Python?

I liked zzzeek's answer. I would just substitute the Pipe for a Queue since if multiple threads/processes use the same pipe end to generate log messages they will get garbled.

How do I check if an index exists on a table field in MySQL?

You can't run a specific show index query because it will throw an error if an index does not exist. Therefore, you have to grab all indexes into an array and loop through them if you want to avoid any SQL errors.

Heres how I do it. I grab all of the indexes from the table (in this case, leads) and then, in a foreach loop, check if the column name (in this case, province) exists or not.

$this->name = 'province';

$stm = $this->db->prepare('show index from `leads`');
$stm->execute();
$res = $stm->fetchAll();
$index_exists = false;

foreach ($res as $r) {
    if ($r['Column_name'] == $this->name) {
        $index_exists = true;
    }
}

This way you can really narrow down the index attributes. Do a print_r of $res in order to see what you can work with.

VIM Disable Automatic Newline At End Of File

I found this vimscript plugin is helpful for this situation.

Plugin 'vim-scripts/PreserveNoEOL'

Or read more at github

What is WebKit and how is it related to CSS?

Webkit is the html/css rendering engine used in Apple's Safari browser, and in Google's Chrome. css values prefixes with -webkit- are webkit-specific, they're usually CSS3 or other non-standardised features.

to answer update 2 w3c is the body that tries to standardize these things, they write the rules, then programmers write their rendering engine to interpret those rules. So basically w3c says DIVs should work "This way" the engine-writer then uses that rule to write their code, any bugs or mis-interpretations of the rules cause the compatibility issues.

What is the most efficient way of finding all the factors of a number in Python?

For n up to 10**16 (maybe even a bit more), here is a fast pure Python 3.6 solution,

from itertools import compress

def primes(n):
    """ Returns  a list of primes < n for n > 2 """
    sieve = bytearray([True]) * (n//2)
    for i in range(3,int(n**0.5)+1,2):
        if sieve[i//2]:
            sieve[i*i//2::i] = bytearray((n-i*i-1)//(2*i)+1)
    return [2,*compress(range(3,n,2), sieve[1:])]

def factorization(n):
    """ Returns a list of the prime factorization of n """
    pf = []
    for p in primeslist:
      if p*p > n : break
      count = 0
      while not n % p:
        n //= p
        count += 1
      if count > 0: pf.append((p, count))
    if n > 1: pf.append((n, 1))
    return pf

def divisors(n):
    """ Returns an unsorted list of the divisors of n """
    divs = [1]
    for p, e in factorization(n):
        divs += [x*p**k for k in range(1,e+1) for x in divs]
    return divs

n = 600851475143
primeslist = primes(int(n**0.5)+1) 
print(divisors(n))

Easy interview question got harder: given numbers 1..100, find the missing number(s) given exactly k are missing

I'd take a different approach to that question and probe the interviewer for more details about the larger problem he's trying to solve. Depending on the problem and the requirements surrounding it, the obvious set-based solution might be the right thing and the generate-a-list-and-pick-through-it-afterward approach might not.

For example, it might be that the interviewer is going to dispatch n messages and needs to know the k that didn't result in a reply and needs to know it in as little wall clock time as possible after the n-kth reply arrives. Let's also say that the message channel's nature is such that even running at full bore, there's enough time to do some processing between messages without having any impact on how long it takes to produce the end result after the last reply arrives. That time can be put to use inserting some identifying facet of each sent message into a set and deleting it as each corresponding reply arrives. Once the last reply has arrived, the only thing to be done is to remove its identifier from the set, which in typical implementations takes O(log k+1). After that, the set contains the list of k missing elements and there's no additional processing to be done.

This certainly isn't the fastest approach for batch processing pre-generated bags of numbers because the whole thing runs O((log 1 + log 2 + ... + log n) + (log n + log n-1 + ... + log k)). But it does work for any value of k (even if it's not known ahead of time) and in the example above it was applied in a way that minimizes the most critical interval.

Should 'using' directives be inside or outside the namespace?

As Jeppe Stig Nielsen said, this thread already has great answers, but I thought this rather obvious subtlety was worth mentioning too.

using directives specified inside namespaces can make for shorter code since they don't need to be fully qualified as when they're specified on the outside.

The following example works because the types Foo and Bar are both in the same global namespace, Outer.

Presume the code file Foo.cs:

namespace Outer.Inner
{
    class Foo { }
}

And Bar.cs:

namespace Outer
{
    using Outer.Inner;

    class Bar
    {
        public Foo foo;
    }
}

That may omit the outer namespace in the using directive, for short:

namespace Outer
{
    using Inner;

    class Bar
    {
        public Foo foo;
    }
}

java.security.cert.CertificateException: Certificates does not conform to algorithm constraints

I have this issue in SOAP-UI and no one solution above dont helped me.

Proper solution for me was to add

-Dsoapui.sslcontext.algorithm=TLSv1

in vmoptions file (in my case it was ...\SoapUI-5.4.0\bin\SoapUI-5.4.0.vmoptions)

How to highlight text using javascript

Why using a selfmade highlighting function is a bad idea

The reason why it's probably a bad idea to start building your own highlighting function from scratch is because you will certainly run into issues that others have already solved. Challenges:

  • You would need to remove text nodes with HTML elements to highlight your matches without destroying DOM events and triggering DOM regeneration over and over again (which would be the case with e.g. innerHTML)
  • If you want to remove highlighted elements you would have to remove HTML elements with their content and also have to combine the splitted text-nodes for further searches. This is necessary because every highlighter plugin searches inside text nodes for matches and if your keywords will be splitted into several text nodes they will not being found.
  • You would also need to build tests to make sure your plugin works in situations which you have not thought about. And I'm talking about cross-browser tests!

Sounds complicated? If you want some features like ignoring some elements from highlighting, diacritics mapping, synonyms mapping, search inside iframes, separated word search, etc. this becomes more and more complicated.

Use an existing plugin

When using an existing, well implemented plugin, you don't have to worry about above named things. The article 10 jQuery text highlighter plugins on Sitepoint compares popular highlighter plugins.

Have a look at mark.js

mark.js is such a plugin that is written in pure JavaScript, but is also available as jQuery plugin. It was developed to offer more opportunities than the other plugins with options to:

  • search for keywords separately instead of the complete term
  • map diacritics (For example if "justo" should also match "justò")
  • ignore matches inside custom elements
  • use custom highlighting element
  • use custom highlighting class
  • map custom synonyms
  • search also inside iframes
  • receive not found terms

DEMO

Alternatively you can see this fiddle.

Usage example:

// Highlight "keyword" in the specified context
$(".context").mark("keyword");

// Highlight the custom regular expression in the specified context
$(".context").markRegExp(/Lorem/gmi);

It's free and developed open-source on GitHub (project reference).

Quickly create a large file on a Linux system

The GPL mkfile is just a (ba)sh script wrapper around dd; BSD's mkfile just memsets a buffer with non-zero and writes it repeatedly. I would not expect the former to out-perform dd. The latter might edge out dd if=/dev/zero slightly since it omits the reads, but anything that does significantly better is probably just creating a sparse file.

Absent a system call that actually allocates space for a file without writing data (and Linux and BSD lack this, probably Solaris as well) you might get a small improvement in performance by using ftrunc(2)/truncate(1) to extend the file to the desired size, mmap the file into memory, then write non-zero data to the first bytes of every disk block (use fgetconf to find the disk block size).

Xcode 6 iPhone Simulator Application Support location

This worked for me in swift:

let dirPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
println("App Path: \(dirPaths)")

What in layman's terms is a Recursive Function using PHP

Basically this. It keeps calling itself until its done

void print_folder(string root)
{
    Console.WriteLine(root);
    foreach(var folder in Directory.GetDirectories(root))
    {
        print_folder(folder);
    }
}

Also works with loops!

void pretend_loop(int c)
{
    if(c==0) return;
    print "hi";
    pretend_loop(c-);
}

You can also trying googling it. Note the "Did you mean" (click on it...). http://www.google.com/search?q=recursion&spell=1

"Could not load type [Namespace].Global" causing me grief

In my case, It was because of my target processor (x64) I changed it to x86 cleaned the project, restarted VS(2012) and rebuilt the project; then it was gone.

Laravel 5 Eloquent where and or in Clauses

Using advanced wheres:

CabRes::where('m__Id', 46)
      ->where('t_Id', 2)
      ->where(function($q) {
          $q->where('Cab', 2)
            ->orWhere('Cab', 4);
      })
      ->get();

Or, even better, using whereIn():

CabRes::where('m__Id', 46)
      ->where('t_Id', 2)
      ->whereIn('Cab', $cabIds)
      ->get();

Shift column in pandas dataframe up by one?

shift column gdp up:

df.gdp = df.gdp.shift(-1)

and then remove the last row

CSS for grabbing cursors (drag & drop)

I may be late, but you can try the following code, which worked for me for Drag and Drop.

.dndclass{
    cursor: url('../images/grab1.png'), auto; 

}

.dndclass:active {
    cursor: url('../images/grabbing1.png'), auto;
}

You can use the images below in the URL above. Make sure it is a PNG transparent image. If not, download one from google.

enter image description here enter image description here

add elements to object array

You can use class System.Array for add new element:

Array.Resize(ref objArray, objArray.Length + 1);
objArray[objArray.Length - 1] = new Someobject();

TensorFlow not found using pip

Excerpt from tensorflow website https://www.tensorflow.org/install/install_windows

Installing with native pip

If the following version of Python is not installed on your machine, install it now:

Python 3.5.x from python.org TensorFlow only supports version 3.5.x of Python on Windows. Note that Python 3.5.x comes with the pip3 package manager, which is the program you'll use to install TensorFlow.

To install TensorFlow, start a terminal. Then issue the appropriate pip3 install command in that terminal. To install the CPU-only version of TensorFlow, enter the following command:

C:\> pip3 install --upgrade tensorflow
To install the GPU version of TensorFlow, enter the following command:

C:\> pip3 install --upgrade tensorflow-gpu

How to use XPath preceding-sibling correctly

I also like to build locators from up to bottom like:

//div[contains(@class,'btn-group')][./button[contains(.,'Arcade Reader')]]/button[@name='settings']

It's pretty simple, as we just search btn-group with button[contains(.,'Arcade Reader')] and get it's button[@name='settings']

That's just another option to build xPath locators

What is the profit of searching wrapper element: you can return it by method (example in java) and just build selenium constructions like:

getGroupByName("Arcade Reader").find("button[name='settings']");
getGroupByName("Arcade Reader").find("button[name='delete']");

or even simplify more

getGroupButton("Arcade Reader", "delete").click();

How do I stretch a background image to cover the entire HTML element?

image{

background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
  padding: 0 3em 0 3em; 
margin: -1.5em -0.5em -0.5em -1em; 
  width: absolute;
  max-width: 100%; 

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

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

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

when in doubt, use VARCHAR2(1 CHAR)

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

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

in Oracle, don't use VARCHAR

Javascript : Send JSON Object with Ajax?

Adding Json.stringfy around the json that fixed the issue

Trigger a button click with JavaScript on the Enter key in a text box

In jQuery, you can use event.which==13. If you have a form, you could use $('#formid').submit() (with the correct event listeners added to the submission of said form).

_x000D_
_x000D_
$('#textfield').keyup(function(event){_x000D_
   if(event.which==13){_x000D_
       $('#submit').click();_x000D_
   }_x000D_
});_x000D_
$('#submit').click(function(e){_x000D_
   if($('#textfield').val().trim().length){_x000D_
      alert("Submitted!");_x000D_
   } else {_x000D_
    alert("Field can not be empty!");_x000D_
   }_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<label for="textfield">_x000D_
Enter Text:</label>_x000D_
<input id="textfield" type="text">_x000D_
<button id="submit">_x000D_
Submit_x000D_
</button>
_x000D_
_x000D_
_x000D_

How do I draw a grid onto a plot in Python?

To show a grid line on every tick, add

plt.grid(True)

For example:

import matplotlib.pyplot as plt

points = [
    (0, 10),
    (10, 20),
    (20, 40),
    (60, 100),
]

x = list(map(lambda x: x[0], points))
y = list(map(lambda x: x[1], points))

plt.scatter(x, y)
plt.grid(True)

plt.show()

enter image description here


In addition, you might want to customize the styling (e.g. solid line instead of dashed line), add:

plt.rc('grid', linestyle="-", color='black')

For example:

import matplotlib.pyplot as plt

points = [
    (0, 10),
    (10, 20),
    (20, 40),
    (60, 100),
]

x = list(map(lambda x: x[0], points))
y = list(map(lambda x: x[1], points))

plt.rc('grid', linestyle="-", color='black')
plt.scatter(x, y)
plt.grid(True)

plt.show()

enter image description here

How to assign execute permission to a .sh file in windows to be executed in linux

As far as I know the permission system in Linux is set up in such a way to prevent exactly what you are trying to accomplish.

I think the best you can do is to give your Linux user a custom unzip one-liner to run on the prompt:

unzip zip_name.zip && chmod +x script_name.sh

If there are multiple scripts that you need to give execute permission to, write a grant_perms.sh as follows:

#!/bin/bash
# file: grant_perms.sh

chmod +x script_1.sh
chmod +x script_2.sh
...
chmod +x script_n.sh

(You can put the scripts all on one line for chmod, but I found separate lines easier to work with in vim and with shell script commands.)

And now your unzip one-liner becomes:

unzip zip_name.zip && source grant_perms.sh

Note that since you are using source to run grant_perms.sh, it doesn't need execute permission

convert base64 to image in javascript/jquery

Have to add this based on @Joseph's answer. If someone want to create image object:

var image = new Image();
image.onload = function(){
   console.log(image.width); // image is loaded and we have image width 
}
image.src = 'data:image/png;base64,iVBORw0K...';
document.body.appendChild(image);

Cleanest way to reset forms

You can also do it through the JavaScript:

(document.querySelector("form_selector") as HTMLFormElement).reset();

Trust Anchor not found for Android SSL Connection

The Trust anchor error can happen for a lot of reasons. For me it was simply that I was trying to access https://example.com/ instead of https://www.example.com/.

So you might want to double-check your URLs before starting to build your own Trust Manager (like I did).

Xcode error - Thread 1: signal SIGABRT

SIGABRT is, as stated in other answers, a general uncaught exception. You should definitely learn a little bit more about Objective-C. The problem is probably in your UITableViewDelegate method didSelectRowAtIndexPath.

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

I can't tell you much more until you show us something of the code where you handle the table data source and delegate methods.

Amazon S3 upload file and get URL

Similarly if you want link through s3Client you can use below.

System.out.println("filelink: " + s3Client.getUrl("your_bucket_name", "your_file_key"));

XML Parsing - Read a Simple XML File and Retrieve Values

I usually use XmlDocument for this. The interface is pretty straight forward:

var doc = new XmlDocument();
doc.LoadXml(xmlString);

You can access nodes similar to a dictionary:

var tasks = doc["Tasks"];

and loop over all children of a node.

Specifying trust store information in spring boot application.properties

In case if you need to make a REST call you can use the next way.

This will work for outgoing calls through RestTemplate.

Declare the RestTemplate bean like this.

@Configuration
public class SslConfiguration {
    @Value("${http.client.ssl.trust-store}")
    private Resource keyStore;
    @Value("${http.client.ssl.trust-store-password}")
    private String keyStorePassword;

    @Bean
    RestTemplate restTemplate() throws Exception {
        SSLContext sslContext = new SSLContextBuilder()
                .loadTrustMaterial(
                        keyStore.getURL(),
                        keyStorePassword.toCharArray()
                ).build();
        SSLConnectionSocketFactory socketFactory = 
                new SSLConnectionSocketFactory(sslContext);
        HttpClient httpClient = HttpClients.custom()
                .setSSLSocketFactory(socketFactory).build();
        HttpComponentsClientHttpRequestFactory factory = 
                new HttpComponentsClientHttpRequestFactory(httpClient);
        return new RestTemplate(factory);
    }
}

Where http.client.ssl.trust-store and http.client.ssl.trust-store-password points to truststore in JKS format and the password for the specified truststore.

This will override the RestTemplate bean provided with Spring Boot and make it use the trust store you need.

How to change collation of database, table, column?

I am contributing here, as the OP asked:

How to change collation of database, table, column?

The selected answer just states it on table level.


Changing it database wide:

ALTER DATABASE <database_name> CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Changing it per table:

ALTER TABLE <table_name> CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Good practice is to change it at table level as it'll change it for columns as well. Changing for specific column is for any specific case.

Changing collation for a specific column:

ALTER TABLE <table_name> MODIFY <column_name> VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

How to open .SQLite files

My favorite:

https://inloop.github.io/sqlite-viewer/

No installation needed. Just drop the file.

Why must wait() always be in synchronized block

This basically has to do with the hardware architecture (i.e. RAM and caches).

If you don't use synchronized together with wait() or notify(), another thread could enter the same block instead of waiting for the monitor to enter it. Moreover, when e.g. accessing an array without a synchronized block, another thread may not see the changement to it...actually another thread will not see any changements to it when it already has a copy of the array in the x-level cache (a.k.a. 1st/2nd/3rd-level caches) of the thread handling CPU core.

But synchronized blocks are only one side of the medal: If you actually access an object within a synchronized context from a non-synchronized context, the object still won't be synchronized even within a synchronized block, because it holds an own copy of the object in its cache. I wrote about this issues here: https://stackoverflow.com/a/21462631 and When a lock holds a non-final object, can the object's reference still be changed by another thread?

Furthermore, I'm convinced that the x-level caches are responsible for most non-reproducible runtime errors. That's because the developers usually don't learn the low-level stuff, like how CPU's work or how the memory hierarchy affects the running of applications: http://en.wikipedia.org/wiki/Memory_hierarchy

It remains a riddle why programming classes don't start with memory hierarchy and CPU architecture first. "Hello world" won't help here. ;)

Exclude Blank and NA in R

Don't know exactly what kind of dataset you have, so I provide general answer.

x <- c(1,2,NA,3,4,5)
y <- c(1,2,3,NA,6,8)
my.data <- data.frame(x, y)
> my.data
   x  y
1  1  1
2  2  2
3 NA  3
4  3 NA
5  4  6
6  5  8
# Exclude rows with NA values
my.data[complete.cases(my.data),]
  x y
1 1 1
2 2 2
5 4 6
6 5 8

AngularJS - How can I do a redirect with a full page load?

For <a> tags:

You need to stick target="_self" on your <a> tag

There are three cases where AngularJS will perform a full page reload:

  • Links that contain target element
    Example: <a href="/ext/link?a=b" target="_self">link</a>
  • Absolute links that go to a different domain
    Example: <a href="http://angularjs.org/">link</a>
  • Links starting with '/' that lead to a different base path when base is defined
    Example: <a href="/not-my-base/link">link</a>

Using javascript:

The $location service allows you to change only the URL; it does not allow you to reload the page. When you need to change the URL and reload the page or navigate to a different page, please use a lower level API: $window.location.href.

See:

Markdown `native` text alignment

It's hacky but if you're using GFM or some other MD syntax which supports building tables with pipes you can use the column alignment features:

|| <!-- empty table header -->
|:--:| <!-- table header/body separator with center formatting -->
| I'm centered! | <!-- cell gets column's alignment -->

This works in marked.

Getting Lat/Lng from Google marker

Here is the JSFiddle Demo. In Google Maps API V3 it's pretty simple to track the lat and lng of a draggable marker. Let's start with the following HTML and CSS as our base.

<div id='map_canvas'></div>
<div id="current">Nothing yet...</div>

#map_canvas{
    width: 400px;
    height: 300px;
}

#current{
     padding-top: 25px;
}

Here is our initial JavaScript initializing the google map. We create a marker that we want to drag and set it's draggable property to true. Of course keep in mind it should be attached to an onload event of your window for it to be loaded, but i'll skip to the code:

var map = new google.maps.Map(document.getElementById('map_canvas'), {
    zoom: 1,
    center: new google.maps.LatLng(35.137879, -82.836914),
    mapTypeId: google.maps.MapTypeId.ROADMAP
});

var myMarker = new google.maps.Marker({
    position: new google.maps.LatLng(47.651968, 9.478485),
    draggable: true
});

Here we attach two events dragstart to track the start of dragging and dragend to drack when the marker stop getting dragged, and the way we attach it is to use google.maps.event.addListener. What we are doing here is setting the div current's content when marker is getting dragged and then set the marker's lat and lng when drag stops. Google mouse event has a property name 'latlng' that returns 'google.maps.LatLng' object when the event triggers. So, what we are doing here is basically using the identifier for this listener that gets returned by the google.maps.event.addListener and get the property latLng to extract the dragend's current position. Once we get that Lat Lng when the drag stops we'll display within your current div:

google.maps.event.addListener(myMarker, 'dragend', function(evt){
    document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
});

google.maps.event.addListener(myMarker, 'dragstart', function(evt){
    document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
});

Lastly, we'll center our marker and display it on the map:

map.setCenter(myMarker.position);
myMarker.setMap(map);

Let me know if you have any questions regarding my answer.

Difference between iCalendar (.ics) and the vCalendar (.vcs)

iCalendar was based on a vCalendar and Outlook 2007 handles both formats well so it doesn't really matters which one you choose.

I'm not sure if this stands for Outlook 2003. I guess you should give it a try.

Outlook's default calendar format is iCalendar (*.ics)

How do I list loaded plugins in Vim?

Not a VIM user myself, so forgive me if this is totally offbase. But according to what I gather from the following VIM Tips site:

" where was an option set  
:scriptnames            : list all plugins, _vimrcs loaded (super)  
:verbose set history?   : reveals value of history and where set  
:function               : list functions  
:func SearchCompl       : List particular function

"401 Unauthorized" on a directory

It is likely that you do not have the IUSR_computername permission on that folder. I've just had a quick scan and it looks like you will find the information you need here.

If that isn't the case, are you prompted for your username and password by the browser? If so it may be that IIS is configured to use Integrated authentication only, as described here.

SEVERE: Unable to create initial connections of pool - tomcat 7 with context.xml file

I use sprint-boot (2.1.1), and mysql version is 8.0.13. I add dependency in pom, solve my problem.

 <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.13</version>
 </dependency>

MySQL Connector/J » 8.0.13 link: https://mvnrepository.com/artifact/mysql/mysql-connector-java/8.0.13
MySQL Connector/J » All the version link: https://mvnrepository.com/artifact/mysql/mysql-connector-java

how to change background image of button when clicked/focused?

  1. Create a file in drawable play_pause.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_selected="true"
          android:drawable="@drawable/pause" />

    <item android:state_selected="false"
          android:drawable="@drawable/play" />
    <!-- default -->
</selector>
  1. In xml file add this below code
 <ImageView
                android:id="@+id/iv_play"
                android:layout_width="@dimen/_50sdp"
                android:layout_height="@dimen/_50sdp"
                android:layout_centerInParent="true"
                android:layout_centerHorizontal="true"
                android:background="@drawable/pause_button"
                android:gravity="center"
                android:scaleType="fitXY" />
  1. In java file add this below code
iv_play = (ImageView) findViewById(R.id.iv_play);
iv_play.setSelected(false);

and also add this

iv_play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                iv_play.setSelected(!iv_play.isSelected());
                if (iv_play.isSelected()) {
                    ((GifDrawable) gif_1.getDrawable()).start();
                    ((GifDrawable) gif_2.getDrawable()).start();
                } else {
                    iv_play.setSelected(false);
                    ((GifDrawable) gif_1.getDrawable()).stop();
                    ((GifDrawable) gif_2.getDrawable()).stop();
                }
            }
        });

Where does one get the "sys/socket.h" header/source file?

I would like just to add that if you want to use windows socket library you have to :

  • at the beginning : call WSAStartup()

  • at the end : call WSACleanup()

Regards;

How do I convert a String object into a Hash object?

I prefer to abuse ActiveSupport::JSON. Their approach is to convert the hash to yaml and then load it. Unfortunately the conversion to yaml isn't simple and you'd probably want to borrow it from AS if you don't have AS in your project already.

We also have to convert any symbols into regular string-keys as symbols aren't appropriate in JSON.

However, its unable to handle hashes that have a date string in them (our date strings end up not being surrounded by strings, which is where the big issue comes in):

string = '{'last_request_at' : 2011-12-28 23:00:00 UTC }' ActiveSupport::JSON.decode(string.gsub(/:([a-zA-z])/,'\\1').gsub('=>', ' : '))

Would result in an invalid JSON string error when it tries to parse the date value.

Would love any suggestions on how to handle this case

Alphanumeric, dash and underscore but no spaces regular expression check JavaScript

Got stupid error. So post here, if anyone find it useful

  1. [-\._] - means hyphen, dot and underscore
  2. [\.-_] - means all signs in range from dot to underscore

CSS Disabled scrolling

Try using the following code snippet. This should solve your issue.

body, html { 
    overflow-x: hidden; 
    overflow-y: auto;
}

onActivityResult is not being called in Fragment

I can add two advices if someone still cannot make it. In Manifest.xml file, make sure the hosting activity didn't finish when call back and the activity to be started has the launch mode as standard. See details as below:

For Hosting activity, set the no history property as false if have

android:noHistory="false"

For Activity to be started, set the launch mode as standard if have

android:launchMode="standard"

Running a cron job on Linux every six hours

You should include a path to your command, since cron runs with an extensively cut-down environment. You won't have all the environment variables you have in your interactive shell session.

It's a good idea to specify an absolute path to your script/binary, or define PATH in the crontab itself. To help debug any issues I would also redirect stdout/err to a log file.

Batch script: how to check for admin rights

Literally dozens of answers in this and linked questions and elsewhere at SE, all of which are deficient in this way or another, have clearly shown that Windows doesn't provide a reliable built-in console utility. So, it's time to roll out your own.

The following C code, based on Detect if program is running with full administrator rights, works in Win2k+1, anywhere and in all cases (UAC, domains, transitive groups...) - because it does the same as the system itself when it checks permissions. It signals of the result both with a message (that can be silenced with a switch) and exit code.

It only needs to be compiled once, then you can just copy the .exe everywhere - it only depends on kernel32.dll and advapi32.dll (I've uploaded a copy).

chkadmin.c:

#include <malloc.h>
#include <stdio.h>
#include <windows.h>
#pragma comment (lib,"Advapi32.lib")

int main(int argc, char** argv) {
    BOOL quiet = FALSE;
    DWORD cbSid = SECURITY_MAX_SID_SIZE;
    PSID pSid = _alloca(cbSid);
    BOOL isAdmin;

    if (argc > 1) {
        if (!strcmp(argv[1],"/q")) quiet=TRUE;
        else if (!strcmp(argv[1],"/?")) {fprintf(stderr,"Usage: %s [/q]\n",argv[0]);return 0;}
    }

    if (!CreateWellKnownSid(WinBuiltinAdministratorsSid,NULL,pSid,&cbSid)) {
        fprintf(stderr,"CreateWellKnownSid: error %d\n",GetLastError());exit(-1);}

    if (!CheckTokenMembership(NULL,pSid,&isAdmin)) {
        fprintf(stderr,"CheckTokenMembership: error %d\n",GetLastError());exit(-1);}

    if (!quiet) puts(isAdmin ? "Admin" : "Non-admin");
    return !isAdmin;
}

1MSDN claims the APIs are XP+ but this is false. CheckTokenMembership is 2k+ and the other one is even older. The last link also contains a much more complicated way that would work even in NT.

How can I build multiple submit buttons django form?

It's an old question now, nevertheless I had the same issue and found a solution that works for me: I wrote MultiRedirectMixin.

from django.http import HttpResponseRedirect

class MultiRedirectMixin(object):
    """
    A mixin that supports submit-specific success redirection.
     Either specify one success_url, or provide dict with names of 
     submit actions given in template as keys
     Example: 
       In template:
         <input type="submit" name="create_new" value="Create"/>
         <input type="submit" name="delete" value="Delete"/>
       View:
         MyMultiSubmitView(MultiRedirectMixin, forms.FormView):
             success_urls = {"create_new": reverse_lazy('create'),
                               "delete": reverse_lazy('delete')}
    """
    success_urls = {}  

    def form_valid(self, form):
        """ Form is valid: Pick the url and redirect.
        """

        for name in self.success_urls:
            if name in form.data:
                self.success_url = self.success_urls[name]
                break

        return HttpResponseRedirect(self.get_success_url())

    def get_success_url(self):
        """
        Returns the supplied success URL.
        """
        if self.success_url:
            # Forcing possible reverse_lazy evaluation
            url = force_text(self.success_url)
        else:
            raise ImproperlyConfigured(
                _("No URL to redirect to. Provide a success_url."))
        return url

Plugin org.apache.maven.plugins:maven-clean-plugin:2.5 or one of its dependencies could not be resolved

I resolved this issue by switching to the oracle jdk from open jdk 8.

$ java -version java version "1.8.0_221" Java(TM) SE Runtime Environment (build 1.8.0_221-b11) Java HotSpot(TM) 64-Bit Server VM (build 25.221-b11, mixed mode)

Getter and Setter declaration in .NET

With this, you can perform some code in the get or set scope.

private string _myProperty;
public string myProperty
{
    get { return _myProperty; }
    set { _myProperty = value; }
}

You also can use automatic properties:

public string myProperty
{
    get;
    set;
}

And .Net Framework will manage for you. It was create because it is a good pratice and make it easy to do.

You also can control the visibility of these scopes, for sample:

public string myProperty
{
    get;
    private set;
}

public string myProperty2
{
    get;
    protected set;
}

public string myProperty3
{
    get; 
}

Update

Now in C# you can initialize the value of a property. For sample:

public int Property { get; set; } = 1;

If also can define it and make it readonly, without a set.

public int Property { get; } = 1;

And finally, you can define an arrow function.

public int Property => GetValue();

How to update a value, given a key in a hashmap?

It may be little late but here are my two cents.

If you are using Java 8 then you can make use of computeIfPresent method. If the value for the specified key is present and non-null then it attempts to compute a new mapping given the key and its current mapped value.

final Map<String,Integer> map1 = new HashMap<>();
map1.put("A",0);
map1.put("B",0);
map1.computeIfPresent("B",(k,v)->v+1);  //[A=0, B=1]

We can also make use of another method putIfAbsent to put a key. If the specified key is not already associated with a value (or is mapped to null) then this method associates it with the given value and returns null, else returns the current value.

In case the map is shared across threads then we can make use of ConcurrentHashMap and AtomicInteger. From the doc:

An AtomicInteger is an int value that may be updated atomically. An AtomicInteger is used in applications such as atomically incremented counters, and cannot be used as a replacement for an Integer. However, this class does extend Number to allow uniform access by tools and utilities that deal with numerically-based classes.

We can use them as shown:

final Map<String,AtomicInteger> map2 = new ConcurrentHashMap<>();
map2.putIfAbsent("A",new AtomicInteger(0));
map2.putIfAbsent("B",new AtomicInteger(0)); //[A=0, B=0]
map2.get("B").incrementAndGet();    //[A=0, B=1]

One point to observe is we are invoking get to get the value for key B and then invoking incrementAndGet() on its value which is of course AtomicInteger. We can optimize it as the method putIfAbsent returns the value for the key if already present:

map2.putIfAbsent("B",new AtomicInteger(0)).incrementAndGet();//[A=0, B=2]

On a side note if we plan to use AtomicLong then as per documentation under high contention expected throughput of LongAdder is significantly higher, at the expense of higher space consumption. Also check this question.

Difference between document.addEventListener and window.addEventListener?

The document and window are different objects and they have some different events. Using addEventListener() on them listens to events destined for a different object. You should use the one that actually has the event you are interested in.

For example, there is a "resize" event on the window object that is not on the document object.

For example, the "DOMContentLoaded" event is only on the document object.

So basically, you need to know which object receives the event you are interested in and use .addEventListener() on that particular object.

Here's an interesting chart that shows which types of objects create which types of events: https://developer.mozilla.org/en-US/docs/DOM/DOM_event_reference


If you are listening to a propagated event (such as the click event), then you can listen for that event on either the document object or the window object. The only main difference for propagated events is in timing. The event will hit the document object before the window object since it occurs first in the hierarchy, but that difference is usually immaterial so you can pick either. I find it generally better to pick the closest object to the source of the event that meets your needs when handling propagated events. That would suggest that you pick document over window when either will work. But, I'd often move even closer to the source and use document.body or even some closer common parent in the document (if possible).

How to read an external properties file in Maven

This answer to a similar question describes how to extend the properties plugin so it can use a remote descriptor for the properties file. The descriptor is basically a jar artifact containing a properties file (the properties file is included under src/main/resources).

The descriptor is added as a dependency to the extended properties plugin so it is on the plugin's classpath. The plugin will search the classpath for the properties file, read the file''s contents into a Properties instance, and apply those properties to the project's configuration so they can be used elsewhere.

Get pandas.read_csv to read empty values as empty string instead of nan

We have a simple argument in Pandas read_csv for this:

Use:

df = pd.read_csv('test.csv', na_filter= False)

Pandas documentation clearly explains how the above argument works.

Link

From an array of objects, extract value of a property as array

Check out Lodash's _.pluck() function or Underscore's _.pluck() function. Both do exactly what you want in a single function call!

var result = _.pluck(objArray, 'foo');

Update: _.pluck() has been removed as of Lodash v4.0.0, in favour of _.map() in combination with something similar to Niet's answer. _.pluck() is still available in Underscore.

Update 2: As Mark points out in the comments, somewhere between Lodash v4 and 4.3, a new function has been added that provides this functionality again. _.property() is a shorthand function that returns a function for getting the value of a property in an object.

Additionally, _.map() now allows a string to be passed in as the second parameter, which is passed into _.property(). As a result, the following two lines are equivalent to the code sample above from pre-Lodash 4.

var result = _.map(objArray, 'foo');
var result = _.map(objArray, _.property('foo'));

_.property(), and hence _.map(), also allow you to provide a dot-separated string or array in order to access sub-properties:

var objArray = [
    {
        someProperty: { aNumber: 5 }
    },
    {
        someProperty: { aNumber: 2 }
    },
    {
        someProperty: { aNumber: 9 }
    }
];
var result = _.map(objArray, _.property('someProperty.aNumber'));
var result = _.map(objArray, _.property(['someProperty', 'aNumber']));

Both _.map() calls in the above example will return [5, 2, 9].

If you're a little more into functional programming, take a look at Ramda's R.pluck() function, which would look something like this:

var result = R.pluck('foo')(objArray);  // or just R.pluck('foo', objArray)

Why "net use * /delete" does not work but waits for confirmation in my PowerShell script?

With PowerShell 5.1 in Windows 10 you can use:

Get-SmbMapping | Remove-SmbMapping -Confirm:$false

$rootScope.$broadcast vs. $scope.$emit

enter image description here

$scope.$emit: This method dispatches the event in the upwards direction (from child to parent)

enter image description here $scope.$broadcast: Method dispatches the event in the downwards direction (from parent to child) to all the child controllers.

enter image description here $scope.$on: Method registers to listen to some event. All the controllers which are listening to that event get notification of the broadcast or emit based on the where those fit in the child-parent hierarchy.

The $emit event can be cancelled by any one of the $scope who is listening to the event.

The $on provides the "stopPropagation" method. By calling this method the event can be stopped from propagating further.

Plunker :https://embed.plnkr.co/0Pdrrtj3GEnMp2UpILp4/

In case of sibling scopes (the scopes which are not in the direct parent-child hierarchy) then $emit and $broadcast will not communicate to the sibling scopes.

enter image description here

For more details please refer to http://yogeshtutorials.blogspot.in/2015/12/event-based-communication-between-angularjs-controllers.html

WPF Check box: Check changed handling

What about the Checked event? Combine that with AttachedCommandBehaviors or something similar, and a DelegateCommand to get a function fired in your viewmodel everytime that event is called.

Cannot connect to the Docker daemon at unix:/var/run/docker.sock. Is the docker daemon running?

You can try out this:

systemctl start docker

It worked fine for me.

P.S.: after if there is commands that you can't do without sudo, try this:

gpasswd -a $USER docker

Writing handler for UIAlertAction

In Swift 4 :

let alert=UIAlertController(title:"someAlert", message: "someMessage", preferredStyle:UIAlertControllerStyle.alert )

alert.addAction(UIAlertAction(title: "ok", style: UIAlertActionStyle.default, handler: {
        _ in print("FOO ")
}))

present(alert, animated: true, completion: nil)

Mongodb service won't start

I tried deleting the lock file, but the real reason that this happened to me was because I was using ~/data/db as the data directory. Mongo needs an absolute path to the database. Once I changed it to /home//data/db, I was in business.

Open Facebook page from Android app?

Declare constants

  private String FACEBOOK_URL="https://www.facebook.com/approids";
    private String FACEBOOK_PAGE_ID="approids";

Declare Method

public String getFacebookPageURL(Context context) {
        PackageManager packageManager = context.getPackageManager();
        try {
            int versionCode = packageManager.getPackageInfo("com.facebook.katana", 0).versionCode;

            boolean activated =  packageManager.getApplicationInfo("com.facebook.katana", 0).enabled;
            if(activated){
                if ((versionCode >= 3002850)) {
                    Log.d("main","fb first url");
                    return "fb://facewebmodal/f?href=" + FACEBOOK_URL;
                } else {
                    return "fb://page/" + FACEBOOK_PAGE_ID;
                }
            }else{
                return FACEBOOK_URL;
            }
        } catch (PackageManager.NameNotFoundException e) {
            return FACEBOOK_URL;
        }
    }

Call Function

Intent facebookIntent = new Intent(Intent.ACTION_VIEW);
                String facebookUrl = getFacebookPageURL(MainActivity.this);
                facebookIntent.setData(Uri.parse(facebookUrl));
                startActivity(facebookIntent);

Use Toast inside Fragment

Making a Toast inside Fragment

 Toast.makeText(getActivity(), "Your Text Here!", Toast.LENGTH_SHORT).show();

OR

    Activity activityObj = this.getActivity();

    Toast.makeText(activityObj, "Your Text Here!", Toast.LENGTH_SHORT).show();

OR

Toast.makeText(this, "Your Text Here!", Toast.LENGTH_SHORT).show();

Working with UTF-8 encoding in Python source

Do not forget to verify if your text editor encodes properly your code in UTF-8.

Otherwise, you may have invisible characters that are not interpreted as UTF-8.

Javascript/Jquery to change class onclick?

I would think this: http://jsfiddle.net/Skooljester/S3y5p/1/ should do it. If I don't have the class names 100% correct you can just change them to whatever you need them to be.

What is the difference between "screen" and "only screen" in media queries?

The following is from Adobe docs.


The media queries specification also provides the keyword only, which is intended to hide media queries from older browsers. Like not, the keyword must come at the beginning of the declaration. For example:

media="only screen and (min-width: 401px) and (max-width: 600px)"

Browsers that don't recognize media queries expect a comma-separated list of media types, and the specification says they should truncate each value immediately before the first nonalphanumeric character that isn't a hyphen. So, an old browser should interpret the preceding example as this:

media="only"

Because there is no such media type as only, the stylesheet is ignored. Similarly, an old browser should interpret

media="screen and (min-width: 401px) and (max-width: 600px)"

as

media="screen"

In other words, it should apply the style rules to all screen devices, even though it doesn't know what the media queries mean.

Unfortunately, IE 6–8 failed to implement the specification correctly.

Instead of applying the styles to all screen devices, it ignores the style sheet altogether.

In spite of this behavior, it's still recommended to prefix media queries with only if you want to hide the styles from other, less common browsers.


So, using

media="only screen and (min-width: 401px)"

and

media="screen and (min-width: 401px)"

will have the same effect in IE6-8: both will prevent those styles from being used. They will, however, still be downloaded.

Also, in browsers that support CSS3 media queries, both versions will load the styles if the viewport width is larger than 401px and the media type is screen.

I'm not entirely sure which browsers that don't support CSS3 media queries would need the only version

media="only screen and (min-width: 401px)" 

as opposed to

media="screen and (min-width: 401px)"

to make sure it is not interpreted as

media="screen"

It would be a good test for someone with access to a device lab.

How to use Jackson to deserialise an array of objects

For Generic Implementation:

public static <T> List<T> parseJsonArray(String json,
                                         Class<T> classOnWhichArrayIsDefined) 
                                         throws IOException, ClassNotFoundException {
   ObjectMapper mapper = new ObjectMapper();
   Class<T[]> arrayClass = (Class<T[]>) Class.forName("[L" + classOnWhichArrayIsDefined.getName() + ";");
   T[] objects = mapper.readValue(json, arrayClass);
   return Arrays.asList(objects);
}

What's the most useful and complete Java cheat sheet?

This Quick Reference looks pretty good if you're looking for a language reference. It's especially geared towards the user interface portion of the API.

For the complete API, however, I always use the Javadoc. I reference it constantly.

bash script read all the files in directory

To write it with a while loop you can do:

ls -f /var | while read -r file; do cmd $file; done

The primary disadvantage of this is that cmd is run in a subshell, which causes some difficulty if you are trying to set variables. The main advantages are that the shell does not need to load all of the filenames into memory, and there is no globbing. When you have a lot of files in the directory, those advantages are important (that's why I use -f on ls; in a large directory ls itself can take several tens of seconds to run and -f speeds that up appreciably. In such cases 'for file in /var/*' will likely fail with a glob error.)

How do I create a table based on another table

select * into newtable from oldtable

How to convert a Title to a URL slug in jQuery?

function slugify(content) {
   return content.toLowerCase().replace(/ /g,'-').replace(/[^\w-]+/g,'');
}
// slugify('Hello World');
// this will return 'hello-world';

this works for me fine.

Found it on CodeSnipper

Remove the last line from a file in Bash

Ruby(1.9+)

ruby -ne 'BEGIN{prv=""};print prv ; prv=$_;' file

Immutable vs Mutable types

The goal of this answer is to create a single place to find all the good ideas about how to tell if you are dealing with mutating/nonmutating (immutable/mutable), and where possible, what to do about it? There are times when mutation is undesirable and python's behavior in this regard can feel counter-intuitive to coders coming into it from other languages.

As per a useful post by @mina-gabriel:

Analyzing the above and combining w/ a post by @arrakëën:

What cannot change unexpectedly?

  • scalars (variable types storing a single value) do not change unexpectedly
    • numeric examples: int(), float(), complex()
  • there are some "mutable sequences":
    • str(), tuple(), frozenset(), bytes()

What can?

  • list like objects (lists, dictionaries, sets, bytearray())
  • a post on here also says classes and class instances but this may depend on what the class inherits from and/or how its built.

by "unexpectedly" I mean that programmers from other languages might not expect this behavior (with the exception or Ruby, and maybe a few other "Python like" languages).

Adding to this discussion:

This behavior is an advantage when it prevents you from accidentally populating your code with mutliple copies of memory-eating large data structures. But when this is undesirable, how do we get around it?

With lists, the simple solution is to build a new one like so:

list2 = list(list1)

with other structures ... the solution can be trickier. One way is to loop through the elements and add them to a new empty data structure (of the same type).

functions can mutate the original when you pass in mutable structures. How to tell?

  • There are some tests given on other comments on this thread but then there are comments indicating these tests are not full proof
  • object.function() is a method of the original object but only some of these mutate. If they return nothing, they probably do. One would expect .append() to mutate without testing it given its name. .union() returns the union of set1.union(set2) and does not mutate. When in doubt, the function can be checked for a return value. If return = None, it does not mutate.
  • sorted() might be a workaround in some cases. Since it returns a sorted version of the original, it can allow you to store a non-mutated copy before you start working on the original in other ways. However, this option assumes you don't care about the order of the original elements (if you do, you need to find another way). In contrast .sort() mutates the original (as one might expect).

Non-standard Approaches (in case helpful): Found this on github published under an MIT license:

  • github repository under: tobgu named: pyrsistent
  • What it is: Python persistent data structure code written to be used in place of core data structures when mutation is undesirable

For custom classes, @semicolon suggests checking if there is a __hash__ function because mutable objects should generally not have a __hash__() function.

This is all I have amassed on this topic for now. Other ideas, corrections, etc. are welcome. Thanks.

Multiple selector chaining in jQuery?

You should be able to use:

$('#Edit.myClass, #Create.myClass').plugin({options here});

jQuery | Multiple Selectors

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'

in my case, I had a line Class.forName("com.mysql.jdbc.Driver"); after removing this line code works fine if you have any line for loading "com.mysql.jdbc.Driver" remove it, it doesn't require any more

How to activate an Anaconda environment

If this happens you would need to set the PATH for your environment (so that it gets the right Python from the environment and Scripts\ on Windows).

Imagine you have created an environment called py33 by using:

conda create -n py33 python=3.3 anaconda

Here the folders are created by default in Anaconda\envs, so you need to set the PATH as:

set PATH=C:\Anaconda\envs\py33\Scripts;C:\Anaconda\envs\py33;%PATH%

Now it should work in the command window:

activate py33

The line above is the Windows equivalent to the code that normally appears in the tutorials for Mac and Linux:

$ source activate py33

More info: https://groups.google.com/a/continuum.io/forum/#!topic/anaconda/8T8i11gO39U

Does `anaconda` create a separate PYTHONPATH variable for each new environment?

Can we install Android OS on any Windows Phone and vice versa, and same with iPhone and vice versa?

Android needs to be compiled for every hardware plattform / every device model seperatly with the specific drivers etc. If you manage to do that you need also break the security arrangements every manufacturer implements to prevent the installation of other software - these are also different between each model / manufacturer. So it is possible at in theory, but only there :-)

How to output git log with the first line only?

If you don't want hashes and just the first lines (subject lines):

git log --pretty=format:%s

Remove #N/A in vlookup result

if you are looking to change the colour of the cell in case of vlookup error then go for conditional formatting . To do this go the "CONDITIONAL FORMATTING" > "NEW RULE". In this choose the "Select the rule type" = "Format only cells that contains" . After this the window below changes , in which choose "Error" in the first drop-down .After this proceed accordingly.

ReactJS - Get Height of an element

See this fiddle (actually updated your's)

You need to hook into componentDidMount which is run after render method. There, you get actual height of element.

var DivSize = React.createClass({
    getInitialState() {
    return { state: 0 };
  },

  componentDidMount() {
    const height = document.getElementById('container').clientHeight;
    this.setState({ height });
  },

  render: function() {
    return (
        <div className="test">
        Size: <b>{this.state.height}px</b> but it should be 18px after the render
      </div>
    );
  }
});

ReactDOM.render(
  <DivSize />,
  document.getElementById('container')
);
<script src="https://facebook.github.io/react/js/jsfiddle-integration-babel.js"></script>

<div id="container">
<p>
jnknwqkjnkj<br>
jhiwhiw (this is 36px height)
</p>
    <!-- This element's contents will be replaced with your component. -->
</div>

Random number between 0 and 1 in python

you can use use numpy.random module, you can get array of random number in shape of your choice you want

>>> import numpy as np
>>> np.random.random(1)[0]
0.17425892129128229
>>> np.random.random((3,2))
array([[ 0.7978787 ,  0.9784473 ],
       [ 0.49214277,  0.06749958],
       [ 0.12944254,  0.80929816]])
>>> np.random.random((3,1))
array([[ 0.86725993],
       [ 0.36869585],
       [ 0.2601249 ]])
>>> np.random.random((4,1))
array([[ 0.87161403],
       [ 0.41976921],
       [ 0.35714702],
       [ 0.31166808]])
>>> np.random.random_sample()
0.47108547995356098

Rebase feature branch onto another feature branch

Note: if you were on Branch1, you will with Git 2.0 (Q2 2014) be able to type:

git checkout Branch2
git rebase -

See commit 4f40740 by Brian Gesiak modocache:

rebase: allow "-" short-hand for the previous branch

Teach rebase the same shorthand as checkout and merge to name the branch to rebase the current branch on; that is, that "-" means "the branch we were previously on".

function to remove duplicate characters in a string

/* program to remove the duplicate character in string */
/* Author senthilkumar M*/

char *dup_remove(char *str) 
{
    int i = 0, j = 0, l = strlen(str);
    int flag = 0, result = 0;

    for(i = 0; i < l; i++) {
         result = str[i] - 'a';
         if(flag & (1 << result)) {
            */* if duplicate found remove & shift the array*/*
            for(j = i; j < l; j++) {
                  str[j] = str[j+1];
             }
             i--; 
             l--; /* duplicates removed so string length reduced by 1 character*/
             continue;
         }
         flag |= (1 << result);
     }
     return str;
}

error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' -- Missing /var/run/mysqld/mysqld.sock

There is a bug on Ubuntu with MySQL 5.6 and 5.7 where var/run/mysqld/ would disappear whenever MySQL service stopped or is rebooted. This prevents MySQL from running at all. Found this workaround, which isn't perfect, but at least it gets it running after stopping/reboot:

mkdir /var/run/mysqld/
chown mysqld /var/run/mysqld/

Javascript - object key->value

Use [] notation for string representations of properties:

console.log(obj[name]);

Otherwise it's looking for the "name" property, rather than the "a" property.

IsNothing versus Is Nothing

I agree with "Is Nothing". As stated above, it's easy to negate with "IsNot Nothing".

I find this easier to read...

If printDialog IsNot Nothing Then
    'blah
End If

than this...

If Not obj Is Nothing Then
    'blah
End If

How do I resolve this "ORA-01109: database not open" error?

As the error states - the database is not open - it was previously shut down, and someone left it in the middle of the startup process. They may either be intentional, or unintentional (i.e., it was supposed to be open, but failed to do so).

Assuming that's nothing wrong with the database itself, you could open it with a simple statement:(Since the question is asked specifically in the context of SQLPlus, kindly remember to put a statement terminator(Semicolon) at the end mandatorily, otherwise, it will result in an error.)

ALTER DATABASE OPEN;

Kotlin: How to get and set a text to TextView in Android using Kotlin?

just add below line and access direct xml object

import kotlinx.android.synthetic.main.activity_main.*

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        txt_HelloWorld.text = "abc"
    }

replace activity_main according to your XML name