Programs & Examples On #Error recovery

Using a BOOL property

Apple simply recommends declaring an isX getter for stylistic purposes. It doesn't matter whether you customize the getter name or not, as long as you use the dot notation or message notation with the correct name. If you're going to use the dot notation it makes no difference, you still access it by the property name:

@property (nonatomic, assign) BOOL working;

[self setWorking:YES];         // Or self.working = YES;
BOOL working = [self working]; // Or = self.working;

Or

@property (nonatomic, assign, getter=isWorking) BOOL working;

[self setWorking:YES];           // Or self.working = YES;, same as above
BOOL working = [self isWorking]; // Or = self.working;, also same as above

How to override equals method in Java

I'm not sure of the details as you haven't posted the whole code, but:

  • remember to override hashCode() as well
  • the equals method should have Object, not People as its argument type. At the moment you are overloading, not overriding, the equals method, which probably isn't what you want, especially given that you check its type later.
  • you can use instanceof to check it is a People object e.g. if (!(other instanceof People)) { result = false;}
  • equals is used for all objects, but not primitives. I think you mean age is an int (primitive), in which case just use ==. Note that an Integer (with a capital 'I') is an Object which should be compared with equals.

See What issues should be considered when overriding equals and hashCode in Java? for more details.

Is a GUID unique 100% of the time?

MSDN:

There is a very low probability that the value of the new Guid is all zeroes or equal to any other Guid.

How do you generate a random double uniformly distributed between 0 and 1 from C++?

The C++11 standard library contains a decent framework and a couple of serviceable generators, which is perfectly sufficient for homework assignments and off-the-cuff use.

However, for production-grade code you should know exactly what the specific properties of the various generators are before you use them, since all of them have their caveats. Also, none of them passes standard tests for PRNGs like TestU01, except for the ranlux generators if used with a generous luxury factor.

If you want solid, repeatable results then you have to bring your own generator.

If you want portability then you have to bring your own generator.

If you can live with restricted portability then you can use boost, or the C++11 framework in conjunction with your own generator(s).

More detail - including code for a simple yet fast generator of excellent quality and copious links - can be found in my answers to similar topics:

For professional uniform floating-point deviates there are two more issues to consider:

  • open vs. half-open vs. closed range, i.e. (0,1), [0, 1) or [0,1]
  • method of conversion from integral to floating-point (precision, speed)

Both are actually two sides of the same coin, as the method of conversion takes care of the inclusion/exclusion of 0 and 1. Here are three different methods for the half-open interval:

// exact values computed with bc

#define POW2_M32   2.3283064365386962890625e-010
#define POW2_M64   5.421010862427522170037264004349e-020

double random_double_a ()
{
   double lo = random_uint32() * POW2_M64;
   return lo + random_uint32() * POW2_M32;
}

double random_double_b ()
{
   return random_uint64() * POW2_M64;
}

double random_double_c ()
{
   return int64_t(random_uint64()) * POW2_M64 + 0.5;
}

(random_uint32() and random_uint64() are placeholders for your actual functions and would normally be passed as template parameters)

Method a demonstrates how to create a uniform deviate that is not biassed by excess precision for lower values; the code for 64-bit is not shown because it is simpler and just involves masking off 11 bits. The distribution is uniform for all functions but without this trick there would be more different values in the area closer to 0 than elsewhere (finer grid spacing due to the varying ulp).

Method c shows how to get a uniform deviate faster on certain popular platforms where the FPU knows only a signed 64-bit integral type. What you see most often is method b but there the compiler has to generate lots of extra code under the hood to preserve the unsigned semantics.

Mix and match these principles to create your own tailored solution.

All this is explained in Jürgen Doornik's excellent paper Conversion of High-Period Random Numbers to Floating Point.

Error CS1705: "which has a higher version than referenced assembly"

I had this error because "Rebuild" was not really rebuilding.

Solution: Close Visual Studio, really go and delete the bin folder, then rebuild, it might work better.

Also, sometimes Visual Studio lies about references, so check the HintPathin your .csproj files.

Get textarea text with javascript or Jquery

To get the value from a textarea with an id you just have to do

Edited

$("#area1").val();

If you are having more than one element with the same id in the document then the HTML is invalid.

Spring-boot default profile for integration tests

If you use maven, you can add this in pom.xml:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-failsafe-plugin</artifactId>
            <configuration>
                <argLine>-Dspring.profiles.active=test</argLine>
            </configuration>
        </plugin>
        ...

Then, maven should run your integration tests (*IT.java) using this arugument, and also IntelliJ will start with this profile activated - so you can then specify all properties inside

application-test.yml

and you should not need "-default" properties.

How do I list all cron jobs for all users?

This script outputs the Crontab to a file and also lists all users confirming those which have no crontab entry:

for user in $(cut -f1 -d: /etc/passwd); do 
  echo $user >> crontab.bak
  echo "" >> crontab.bak
  crontab -u $user -l >> crontab.bak 2>> > crontab.bak
done

How to SSH into Docker?

These files will successfully open sshd and run service so you can ssh in locally. (you are using cyberduck aren't you?)

Dockerfile

FROM swiftdocker/swift
MAINTAINER Nobody

RUN apt-get update && apt-get -y install openssh-server supervisor
RUN mkdir /var/run/sshd
RUN echo 'root:password' | chpasswd
RUN sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config

# SSH login fix. Otherwise user is kicked off after login
RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd

ENV NOTVISIBLE "in users profile"
RUN echo "export VISIBLE=now" >> /etc/profile

COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf

EXPOSE 22
CMD ["/usr/bin/supervisord"]

supervisord.conf

[supervisord]
nodaemon=true

[program:sshd]
command=/usr/sbin/sshd -D

to build / run start daemon / jump into shell.

docker build -t swift3-ssh .  
docker run -p 2222:22 -i -t swift3-ssh
docker ps # find container id
docker exec -i -t <containerid> /bin/bash

enter image description here

How to clear exisiting dropdownlist items when its content changes?

Please use the following

ddlCity.Items.Clear();

Twitter Bootstrap dropdown menu

You must include jQuery in the project.

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

I didn't find any doc about this so I just opened a random code example from tutorialrepublic.com http://www.tutorialrepublic.com/twitter-bootstrap-tutorial/bootstrap-dropdowns.php

Hope this helps someone else.

How to clear all input fields in bootstrap modal when clicking data-dismiss button?

There is a more easy and beautiful way:

$('#MyModal').on('hidden.bs.modal', function () {
    $(this).find('form').trigger('reset');
})

reset is dom build-in funtion, you can also use $(this).find('form')[0].reset();

And Bootstrap's modal class exposes a few events for hooking into modal functionality, detail at here.

hide.bs.modal This event is fired immediately when the hide instance method has been called.

hidden.bs.modal This event is fired when the modal has finished being hidden from the user (will wait for CSS transitions to complete).

How to call a function from a string stored in a variable?

My favorite version is the inline version:

${"variableName"} = 12;

$className->{"propertyName"};
$className->{"methodName"}();

StaticClass::${"propertyName"};
StaticClass::{"methodName"}();

You can place variables or expressions inside the brackets too!

Authenticating against Active Directory with Java on Linux

Here's the code I put together based on example from this blog: LINK and this source: LINK.

import com.sun.jndi.ldap.LdapCtxFactory;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Iterator;
import javax.naming.Context;
import javax.naming.AuthenticationException;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.SearchControls;
import javax.naming.directory.SearchResult;
import static javax.naming.directory.SearchControls.SUBTREE_SCOPE;

class App2 {

    public static void main(String[] args) {

        if (args.length != 4 && args.length != 2) {
            System.out.println("Purpose: authenticate user against Active Directory and list group membership.");
            System.out.println("Usage: App2 <username> <password> <domain> <server>");
            System.out.println("Short usage: App2 <username> <password>");
            System.out.println("(short usage assumes 'xyz.tld' as domain and 'abc' as server)");
            System.exit(1);
        }

        String domainName;
        String serverName;

        if (args.length == 4) {
            domainName = args[2];
            serverName = args[3];
        } else {
            domainName = "xyz.tld";
            serverName = "abc";
        }

        String username = args[0];
        String password = args[1];

        System.out
                .println("Authenticating " + username + "@" + domainName + " through " + serverName + "." + domainName);

        // bind by using the specified username/password
        Hashtable props = new Hashtable();
        String principalName = username + "@" + domainName;
        props.put(Context.SECURITY_PRINCIPAL, principalName);
        props.put(Context.SECURITY_CREDENTIALS, password);
        DirContext context;

        try {
            context = LdapCtxFactory.getLdapCtxInstance("ldap://" + serverName + "." + domainName + '/', props);
            System.out.println("Authentication succeeded!");

            // locate this user's record
            SearchControls controls = new SearchControls();
            controls.setSearchScope(SUBTREE_SCOPE);
            NamingEnumeration<SearchResult> renum = context.search(toDC(domainName),
                    "(& (userPrincipalName=" + principalName + ")(objectClass=user))", controls);
            if (!renum.hasMore()) {
                System.out.println("Cannot locate user information for " + username);
                System.exit(1);
            }
            SearchResult result = renum.next();

            List<String> groups = new ArrayList<String>();
            Attribute memberOf = result.getAttributes().get("memberOf");
            if (memberOf != null) {// null if this user belongs to no group at all
                for (int i = 0; i < memberOf.size(); i++) {
                    Attributes atts = context.getAttributes(memberOf.get(i).toString(), new String[] { "CN" });
                    Attribute att = atts.get("CN");
                    groups.add(att.get().toString());
                }
            }

            context.close();

            System.out.println();
            System.out.println("User belongs to: ");
            Iterator ig = groups.iterator();
            while (ig.hasNext()) {
                System.out.println("   " + ig.next());
            }

        } catch (AuthenticationException a) {
            System.out.println("Authentication failed: " + a);
            System.exit(1);
        } catch (NamingException e) {
            System.out.println("Failed to bind to LDAP / get account information: " + e);
            System.exit(1);
        }
    }

    private static String toDC(String domainName) {
        StringBuilder buf = new StringBuilder();
        for (String token : domainName.split("\\.")) {
            if (token.length() == 0)
                continue; // defensive check
            if (buf.length() > 0)
                buf.append(",");
            buf.append("DC=").append(token);
        }
        return buf.toString();
    }

}

Error: Cannot find module 'ejs'

npm install ejs --save worked for me ! ?

On goormIDE, I had this file configuration :

  • container
    • main.js
    • package-lock.json
    • package.json
    • node_modules
    • views
      • home.ejs

In my main.js file, I also had this route

app.get("/", function(req, res){
res.render("home.ejs");
})

npm install ejs -g didn't add the corresponding dependency within the package.json. npm install ejs --save did. I executed the command line from the container directory. Manually it could have been added into the package.json with : **

"dependencies": {
    "ejs": "^3.0.2",}

**

Regular cast vs. static_cast vs. dynamic_cast

C-style casts conflate const_cast, static_cast, and reinterpret_cast.

I wish C++ didn't have C-style casts. C++ casts stand out properly (as they should; casts are normally indicative of doing something bad) and properly distinguish between the different kinds of conversion that casts perform. They also permit similar-looking functions to be written, e.g. boost::lexical_cast, which is quite nice from a consistency perspective.

How do I add a new sourceset to Gradle?

Here is how I achieved this without using configurations{ }.

apply plugin: 'java'

sourceCompatibility = JavaVersion.VERSION_1_6

sourceSets {
    integrationTest {
        java {
            srcDir 'src/integrationtest/java'
        }
        resources {
            srcDir 'src/integrationtest/resources'
        }
        compileClasspath += sourceSets.main.runtimeClasspath
    }
}

task integrationTest(type: Test) {
    description = "Runs Integration Tests"
    testClassesDir = sourceSets.integrationTest.output.classesDir
    classpath += sourceSets.integrationTest.runtimeClasspath
}

Tested using: Gradle 1.4 and Gradle 1.6

Disable resizing of a Windows Forms form

More precisely, add the code below to the private void InitializeComponent() method of the Form class:

this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;

How to convert byte array to string and vice versa?

Here the working code.

            // Encode byte array into string . TemplateBuffer1 is my bytearry variable.

        String finger_buffer = Base64.encodeToString(templateBuffer1, Base64.DEFAULT);
        Log.d(TAG, "Captured biometric device->" + finger_buffer);


        // Decode String into Byte Array. decodedString is my bytearray[] 
        decodedString = Base64.decode(finger_buffer, Base64.DEFAULT);

There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'xxx'

Check the Namespace.

You might assign System.Web.Webpages.Html.SelectListItem in the Controller, instead of System.Web.Mvc.SelectListItem.

How to perform Join between multiple tables in LINQ lambda

For joins, I strongly prefer query-syntax for all the details that are happily hidden (not the least of which are the transparent identifiers involved with the intermediate projections along the way that are apparent in the dot-syntax equivalent). However, you asked regarding Lambdas which I think you have everything you need - you just need to put it all together.

var categorizedProducts = product
    .Join(productcategory, p => p.Id, pc => pc.ProdId, (p, pc) => new { p, pc })
    .Join(category, ppc => ppc.pc.CatId, c => c.Id, (ppc, c) => new { ppc, c })
    .Select(m => new { 
        ProdId = m.ppc.p.Id, // or m.ppc.pc.ProdId
        CatId = m.c.CatId
        // other assignments
    });

If you need to, you can save the join into a local variable and reuse it later, however lacking other details to the contrary, I see no reason to introduce the local variable.

Also, you could throw the Select into the last lambda of the second Join (again, provided there are no other operations that depend on the join results) which would give:

var categorizedProducts = product
    .Join(productcategory, p => p.Id, pc => pc.ProdId, (p, pc) => new { p, pc })
    .Join(category, ppc => ppc.pc.CatId, c => c.Id, (ppc, c) => new {
        ProdId = ppc.p.Id, // or ppc.pc.ProdId
        CatId = c.CatId
        // other assignments
    });

...and making a last attempt to sell you on query syntax, this would look like this:

var categorizedProducts =
    from p in product
    join pc in productcategory on p.Id equals pc.ProdId
    join c in category on pc.CatId equals c.Id
    select new {
        ProdId = p.Id, // or pc.ProdId
        CatId = c.CatId
        // other assignments
    };

Your hands may be tied on whether query-syntax is available. I know some shops have such mandates - often based on the notion that query-syntax is somewhat more limited than dot-syntax. There are other reasons, like "why should I learn a second syntax if I can do everything and more in dot-syntax?" As this last part shows - there are details that query-syntax hides that can make it well worth embracing with the improvement to readability it brings: all those intermediate projections and identifiers you have to cook-up are happily not front-and-center-stage in the query-syntax version - they are background fluff. Off my soap-box now - anyhow, thanks for the question. :)

Change the On/Off text of a toggle button Android

In some cases, you need to force refresh the view in order to make it work.

toggleButton.setTextOff(textOff);
toggleButton.requestLayout();

toggleButton.setTextOn(textOn);
toggleButton.requestLayout();

Where do alpha testers download Google Play Android apps?

You can use a Google Group and have your alpha testers just join the group. Everything else should just be handled through the Google Play Store App.

Copy files without overwrite

I just want to clarify something from my own testing.

@Hydrargyrum wrote:

  • /XN excludes existing files newer than the copy in the source directory. Robocopy normally overwrites those.
  • /XO excludes existing files older than the copy in the source directory. Robocopy normally overwrites those.

This is actually backwards. XN does "eXclude Newer" files but it excludes files that are newer than the copy in the destination directory. XO does "eXclude Older", but it excludes files that are older than the copy in the destination directory.

Of course do your own testing as always.

Java Error: "Your security settings have blocked a local application from running"

  1. Go to Control Panel
  2. Double click on Java
  3. Open the Security tab
  4. Select Medium
  5. Click on Apply
  6. Restart your web browser

That's it!

enter image description here

Convert bytes to int?

Lists of bytes are subscriptable (at least in Python 3.6). This way you can retrieve the decimal value of each byte individually.

>>> intlist = [64, 4, 26, 163, 255]
>>> bytelist = bytes(intlist)       # b'@x04\x1a\xa3\xff'

>>> for b in bytelist:
...    print(b)                     # 64  4  26  163  255

>>> [b for b in bytelist]           # [64, 4, 26, 163, 255]

>>> bytelist[2]                     # 26 

Write Base64-encoded image to file

Other option using apache-commons:

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.FileUtils;

...
File file = new File( "path" );
byte[] bytes = Base64.decodeBase64( "base64" );
FileUtils.writeByteArrayToFile( file, bytes );

Element implicitly has an 'any' type because expression of type 'string' can't be used to index

I made some small changes to Alex McKay's function/usage that I think make it a little easier to follow why it works and also adheres to the no-use-before-define rule.

First, define this function to use:

const getKeyValue = function<T extends object, U extends keyof T> (obj: T, key: U) { return obj[key] }

In the way I've written it, the generic for the function lists the object first, then the property on the object second (these can occur in any order, but if you specify U extends key of T before T extends object you break the no-use-before-define rule, and also it just makes sense to have the object first and its' property second. Finally, I've used the more common function syntax instead of the arrow operators (=>).

Anyways, with those modifications you can just use it like this:

interface User {
  name: string;
  age: number;
}

const user: User = {
  name: "John Smith",
  age: 20
};

getKeyValue(user, "name")

Which, again, I find to be a bit more readable.

SVG: text inside rect

You can use foreignobject for more control and placing rich HTML content over rect or circle

_x000D_
_x000D_
    <svg width="250" height="250" xmlns="http://www.w3.org/2000/svg">_x000D_
        <rect x="0" y="0" width="250" height="250" fill="aquamarine" />_x000D_
        <foreignobject x="0" y="0" width="250" height="250">_x000D_
            <body xmlns="http://www.w3.org/1999/xhtml">_x000D_
                <div>Here is a long text that runs more than one line and works as a paragraph</div>_x000D_
                <br />_x000D_
                <div>This is <u>UNDER LINE</u> one</div>_x000D_
                <br />_x000D_
                <div>This is <b>BOLD</b> one</div>_x000D_
                <br />_x000D_
                <div>This is <i>Italic</i> one</div>_x000D_
            </body>_x000D_
        </foreignobject>_x000D_
    </svg>
_x000D_
_x000D_
_x000D_

enter image description here

Right way to write JSON deserializer in Spring or extend it

I was trying to @Autowire a Spring-managed service into my Deserializer. Somebody tipped me off to Jackson using the new operator when invoking the serializers/deserializers. This meant no auto-wiring of Jackson's instance of my Deserializer. Here's how I was able to @Autowire my service class into my Deserializer:

context.xml

<mvc:annotation-driven>
  <mvc:message-converters>
    <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
      <property name="objectMapper" ref="objectMapper" />
    </bean>
  </mvc:message-converters>
</mvc>
<bean id="objectMapper" class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
    <!-- Add deserializers that require autowiring -->
    <property name="deserializersByType">
        <map key-type="java.lang.Class">
            <entry key="com.acme.Anchor">
                <bean class="com.acme.AnchorDeserializer" />
            </entry>
        </map>
    </property>
</bean>

Now that my Deserializer is a Spring-managed bean, auto-wiring works!

AnchorDeserializer.java

public class AnchorDeserializer extends JsonDeserializer<Anchor> {
    @Autowired
    private AnchorService anchorService;
    public Anchor deserialize(JsonParser parser, DeserializationContext context)
             throws IOException, JsonProcessingException {
        // Do stuff
    }
}

AnchorService.java

@Service
public class AnchorService {}

Update: While my original answer worked for me back when I wrote this, @xi.lin's response is exactly what is needed. Nice find!

Facebook api: (#4) Application request limit reached

The Facebook API limit isn't really documented, but apparently it's something like: 600 calls per 600 seconds, per token & per IP. As the site is restricted, quoting the relevant part:

After some testing and discussion with the Facebook platform team, there is no official limit I'm aware of or can find in the documentation. However, I've found 600 calls per 600 seconds, per token & per IP to be about where they stop you. I've also seen some application based rate limiting but don't have any numbers.

As a general rule, one call per second should not get rate limited. On the surface this seems very restrictive but remember you can batch certain calls and use the subscription API to get changes.

As you can access the Graph API on the client side via the Javascript SDK; I think if you travel your request for photos from the client, you won't hit any application limit as it's the user (each one with unique id) who's fetching data, not your application server (unique ID).

This may mean a huge refactor if everything you do go through a server. But it seems like the best solution if you have so many request (as it'll give a breath to your server).

Else, you can try batch request, but I guess you're already going this way if you have big traffic.


If nothing of this works, according to the Facebook Platform Policy you should contact them.

If you exceed, or plan to exceed, any of the following thresholds please contact us as you may be subject to additional terms: (>5M MAU) or (>100M API calls per day) or (>50M impressions per day).

What's NSLocalizedString equivalent in Swift?

This is an improvement on the ".localized" approach. Start with adding the class extension as this will help with any strings you were setting programatically:

extension String {
    func localized (bundle: Bundle = .main, tableName: String = "Localizable") -> String {
        return NSLocalizedString(self, tableName: tableName, value: "\(self)", comment: "")
    }
}

Example use for strings you set programmatically:

  override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

Now Xcode's storyboard translation files make the file manager messy and don't handle updates to the storyboard well either. A better approach is to create a new basic label class and assign it to all your storyboard labels:

class BasicLabel: UILabel {
    //initWithFrame to init view from code
    override init(frame: CGRect) {
      super.init(frame: frame)
      setupView()
    }

    //initWithCode to init view from xib or storyboard
    required init?(coder aDecoder: NSCoder) {
      super.init(coder: aDecoder)
      setupView()
    }

    //common func to init our view
    private func setupView() {
        let storyboardText = self.text
        text = storyboardText?.localized()
    }
}

Now every label you add and provide default default for in the storyboard will automatically get translated, assuming you've provide a translation for it.

You could do the same for UIButton:

class BasicBtn: UIButton {
    //initWithFrame to init view from code
    override init(frame: CGRect) {
      super.init(frame: frame)
      setupView()
    }

    //initWithCode to init view from xib or storyboard
    required init?(coder aDecoder: NSCoder) {
      super.init(coder: aDecoder)
      setupView()
    }

    //common func to init our view
    private func setupView() {
        let storyboardText = self.titleLabel?.text
        let lclTxt = storyboardText?.localized()
        setTitle(lclTxt, for: .normal)
    }
}

How to convert empty spaces into null values, using SQL Server?

here's a regex one for ya.

update table
set col1=null
where col1 not like '%[a-z,0-9]%'

essentially finds any columns that dont have letters or numbers in them and sets it to null. might have to update if you have columns with just special characters.

JavaScript TypeError: Cannot read property 'style' of null

In your script, this part:

document.getElementById('Noite')

must be returning null and you are also attempting to set the display property to an invalid value. There are a couple of possible reasons for this first part to be null.

  1. You are running the script too early before the document has been loaded and thus the Noite item can't be found.

  2. There is no Noite item in your HTML.

I should point out that your use of document.write() in this case code probably signifies a problem. If the document has already loaded, then a new document.write() will clear the old content and start a new fresh document so no Noite item would be found.

If your document has not yet been loaded and thus you're doing document.write() inline to add HTML inline to the current document, then your document has not yet been fully loaded so that's probably why it can't find the Noite item.

The solution is probably to put this part of your script at the very end of your document so everything before it has already been loaded. So move this to the end of your body:

document.getElementById('Noite').style.display='block';

And, make sure that there are no document.write() statements in javascript after the document has been loaded (because they will clear the previous document and start a new one).


In addition, setting the display property to "display" doesn't make sense to me. The valid options for that are "block", "inline", "none", "table", etc... I'm not aware of any option named "display" for that style property. See here for valid options for teh display property.

You can see the fixed code work here in this demo: http://jsfiddle.net/jfriend00/yVJY4/. That jsFiddle is configured to have the javascript placed at the end of the document body so it runs after the document has been loaded.


P.S. I should point out that your lack of braces for your if statements and your inclusion of multiple statements on the same line makes your code very misleading and unclear.


I'm having a really hard time figuring out what you're asking, but here's a cleaned up version of your code that works which you can also see working here: http://jsfiddle.net/jfriend00/QCxwr/. Here's a list of the changes I made:

  1. The script is located in the body, but after the content that it is referencing.
  2. I've added var declarations to your variables (a good habit to always use).
  3. The if statement was changed into an if/else which is a lot more efficient and more self-documenting as to what you're doing.
  4. I've added braces for every if statement so it absolutely clear which statements are part of the if/else and which are not.
  5. I've properly closed the </dd> tag you were inserting.
  6. I've changed style.display = ''; to style.display = 'block';.
  7. I've added semicolons at the end of every statement (another good habit to follow).

The code:

<div id="Night" style="display: none;">
    <img src="Img/night.png" style="position: fixed; top: 0px; left: 5%; height: auto; width: 100%; z-index: -2147483640;">
    <img src="Img/moon.gif" style="position: fixed; top: 0px; left: 5%; height: 100%; width: auto; z-index: -2147483639;">
</div>    
<script>
document.write("<dl><dd>");
var day = new Date();
var hr = day.getHours();
if (hr == 0) {
    document.write("Meia-noite!<br>Já é amanhã!");
} else if (hr <=5 ) {
    document.write("&nbsp;&nbsp;Você não<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;devia<br>&nbsp;&nbsp;&nbsp;&nbsp;estar<br>dormindo?");
} else if (hr <= 11) {         
    document.write("Bom dia!");
} else if (hr == 12) {
    document.write("&nbsp;&nbsp;&nbsp;&nbsp;Vamos<br>&nbsp;almoçar?");
} else if (hr <= 17) {
    document.write("Boa Tarde");
} else if (hr <= 19) {
    document.write("&nbsp;Bom final<br>&nbsp;de tarde!");
} else if (hr == 20) {
    document.write("&nbsp;Boa Noite"); 
    document.getElementById('Noite').style.display='block';
} else if (hr == 21) {
    document.write("&nbsp;Boa Noite"); 
    document.getElementById('Noite').style.display='none';
} else if (hr == 22) {
    document.write("&nbsp;Boa Noite");
} else if (hr == 23) {
    document.write("Ó Meu! Já é quase meia-noite!");
}
document.write("</dl></dd>");
</script>

How to tell if a string is not defined in a Bash shell script

The Bash Reference Manual is an authoritative source of information about bash.

Here's an example of testing a variable to see if it exists:

if [ -z "$PS1" ]; then
        echo This shell is not interactive
else
        echo This shell is interactive
fi

(From section 6.3.2.)

Note that the whitespace after the open [ and before the ] is not optional.


Tips for Vim users

I had a script that had several declarations as follows:

export VARIABLE_NAME="$SOME_OTHER_VARIABLE/path-part"

But I wanted them to defer to any existing values. So I re-wrote them to look like this:

if [ -z "$VARIABLE_NAME" ]; then
        export VARIABLE_NAME="$SOME_OTHER_VARIABLE/path-part"
fi

I was able to automate this in vim using a quick regex:

s/\vexport ([A-Z_]+)\=("[^"]+")\n/if [ -z "$\1" ]; then\r  export \1=\2\rfi\r/gc

This can be applied by selecting the relevant lines visually, then typing :. The command bar pre-populates with :'<,'>. Paste the above command and hit enter.


Tested on this version of Vim:

VIM - Vi IMproved 7.3 (2010 Aug 15, compiled Aug 22 2015 15:38:58)
Compiled by [email protected]

Windows users may want different line endings.

What's the UIScrollView contentInset property for?

It's used to add padding in UIScrollView

Without contentInset, a table view is like this:

enter image description here

Then set contentInset:

tableView.contentInset = UIEdgeInsets(top: 20, left: 0, bottom: 0, right: 0)

The effect is as below:

enter image description here

Seems to be better, right?

And I write a blog to study the contentInset, criticism is welcome.

mysql query: SELECT DISTINCT column1, GROUP BY column2

Somehow your requirement sounds a bit contradictory ..

group by name (which is basically a distinct on name plus readiness to aggregate) and then a distinct on IP

What do you think should happen if two people (names) worked from the same IP within the time period specified?


Did you try this?

SELECT name, COUNT(name), time, price, ip, SUM(price) 
  FROM tablename 
 WHERE time >= $yesterday AND time <$today 
GROUP BY name,ip

Find MongoDB records where array field is not empty

After some more looking, especially in the mongodb documents, and puzzling bits together, this was the answer:

ME.find({pictures: {$exists: true, $not: {$size: 0}}})

Accessing Arrays inside Arrays In PHP

Regarding your code: It's slightly hard to read... If you want to try to view it all in a php array format, just print_r it. This might help:

<?php
$a =
array(  

  'languages' =>    

  array (   

  76 =>      

 array (       'id' => '76',       'tag' => 'Deutsch',     ),   ),    'targets' =>    
 array (     81 =>      
 array (       'id' => '81',       'tag' => 'Deutschland',     ),   ),    'tags' =>    
 array (     7866 =>      
 array (       'id' => '7866',       'tag' => 'automobile',     ),     17800 =>      
 array (       'id' => '17800',       'tag' => 'seat leon',     ),     17801 =>      
 array (       'id' => '17801',       'tag' => 'seat leon cupra',     ),   ),   
'inactiveTags' =>    
 array (     195 =>      
 array (       'id' => '195',       'tag' => 'auto',     ),     17804 =>      
 array (       'id' => '17804',       'tag' => 'coupès',     ),     17805 =>      
 array (       'id' => '17805',       'tag' => 'fahrdynamik',     ),     901 =>      
 array (       'id' => '901',       'tag' => 'fahrzeuge',     ),     17802 =>      
 array (       'id' => '17802',       'tag' => 'günstige neuwagen',     ),     1991 =>      
 array (       'id' => '1991',       'tag' => 'motorsport',     ),     2154 =>      
 array (       'id' => '2154',       'tag' => 'neuwagen',     ),     10660 =>      
 array (       'id' => '10660',       'tag' => 'seat',     ),     17803 =>      
 array (       'id' => '17803',       'tag' => 'sportliche ausstrahlung',     ),     74 =>      
 array (       'id' => '74',       'tag' => 'web 2.0',     ),   ),    'categories' =>    
 array (     16082 =>      
 array (       'id' => '16082',       'tag' => 'Auto & Motorrad',     ),     51 =>      
 array (       'id' => '51',       'tag' => 'Blogosphäre',     ),     66 =>      
 array (       'id' => '66',       'tag' => 'Neues & Trends',     ),     68 =>      
 array (       'id' => '68',       'tag' => 'Privat',     ),   ), );

 printarr($a);
 printarr($a['languages'][76]['tag']);
 parintarr($a['targets'][81]['id']); 
 function printarr($in){
 echo "\n";
 print_r($in);
 echo "\n";
 }
 //run in php command line php path/to/file.php to test, switching otu the print_r.

How to preventDefault on anchor tags?

HTML

here pure angularjs: near to ng-click function you can write preventDefault() function by seperating semicolon

<a href="#" ng-click="do(); $event.preventDefault(); $event.stopPropagation();">Click me</a>

JS

$scope.do = function() {
    alert("do here anything..");
}

(or)

you can proceed this way, this is already discussed some one here.

HTML

<a href="#" ng-click="do()">Click me</a>

JS

$scope.do = function(event) {
    event.preventDefault();
    event.stopPropagation()
}

"unadd" a file to svn before commit

Full process (Unix svn package):

Check files are not in SVN:

> svn st -u folder 
? folder

Add all (including ignored files):

> svn add folder
A   folder
A   folder/file1.txt
A   folder/folder2
A   folder/folder2/file2.txt
A   folder/folderToIgnore
A   folder/folderToIgnore/fileToIgnore1.txt
A   fileToIgnore2.txt

Remove "Add" Flag to All * Ignore * files:

> cd folder

> svn revert --recursive folderToIgnore
Reverted 'folderToIgnore'
Reverted 'folderToIgnore/fileToIgnore1.txt'


> svn revert fileToIgnore2.txt
Reverted 'fileToIgnore2.txt'

Edit svn ignore on folder

svn propedit svn:ignore .

Add two singles lines with just the following:

folderToIgnore
fileToIgnore2.txt

Check which files will be upload and commit:

> cd ..

> svn st -u
A   folder
A   folder/file1.txt
A   folder/folder2
A   folder/folder2/file2.txt


> svn ci -m "Commit message here"

Python: maximum recursion depth exceeded while calling a Python object

You can increase the capacity of the stack by the following :

import sys
sys.setrecursionlimit(10000)

getResources().getColor() is deprecated

You need to use ContextCompat.getColor(), which is part of the Support V4 Library (so it will work for all the previous API).

ContextCompat.getColor(context, R.color.my_color)

As specified in the documentation, "Starting in M, the returned color will be styled for the specified Context's theme". SO no need to worry about it.

You can add the Support V4 library by adding the following to the dependencies array inside your app build.gradle:

compile 'com.android.support:support-v4:23.0.1'

Regular expression for matching HH:MM time format

You can use this regular expression:

^(2[0-3]|[01]?[0-9]):([1-5]{1}[0-9])$

If you want to exclude 00:00, you can use this expression

^(2[0-3]|[01]?[0-9]):(0[1-9]{1}|[1-5]{1}[0-9])$

Second expression is better option because valid time is 00:01 to 00:59 or 0:01 to 23:59. You can use any of these upon your requirement. Regex101 link

What is more efficient? Using pow to square or just multiply it with itself?

I have been busy with a similar problem, and I'm quite puzzled by the results. I was calculating x?³/² for Newtonian gravitation in an n-bodies situation (acceleration undergone from another body of mass M situated at a distance vector d) : a = M G d*(d²)?³/² (where d² is the dot (scalar) product of d by itself) , and I thought calculating M*G*pow(d2, -1.5) would be simpler than M*G/d2/sqrt(d2)

The trick is that it is true for small systems, but as systems grow in size, M*G/d2/sqrt(d2) becomes more efficient and I don't understand why the size of the system impacts this result, because repeating the operation on different data does not. It is as if there were possible optimizations as the system grow, but which are not possible with pow

enter image description here

Hide Twitter Bootstrap nav collapse on click

Adding the data-toggle="collapse" data-target=".navbar-collapse.in" to the tag <a> worked for me.

<div>

        <button type="button" class="navbar-toggle"  data-toggle="collapse" data-target=".navbar-collapse">
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
        </button>
    </div>
            <div class="navbar-collapse collapse">
            <ul class="nav navbar-nav navbar-right">
                <li class="nav-item"><a
                    href="#" data-toggle="collapse" data-target=".navbar-collapse.in" class="nav-link" >Home
                </a></li>
            </ul>
    </div>

Oracle SQL Query for listing all Schemas in a DB

select distinct owner 
from dba_segments
where owner in (select username from dba_users where default_tablespace not in ('SYSTEM','SYSAUX'));

Find Locked Table in SQL Server

sp_lock

When reading sp_lock information, use the OBJECT_NAME( ) function to get the name of a table from its ID number, for example:

SELECT object_name(16003073)

EDIT :

There is another proc provided by microsoft which reports objects without the ID translation : http://support.microsoft.com/kb/q255596/

Get value from text area

$('textarea').val();

textarea.value would be pure JavaScript, but here you're trying to use JavaScript as a not-valid jQuery method (.value).

Right Align button in horizontal LinearLayout

Use layout width in the button like android:layout_width="75dp"

javascript change background color on click

You can sets the body's background colour using document.body.style.backgroundColor = "red"; so this can be put into a function that's called when the user clicks. The next part can be done by using document.getElementByID("divID").style.backgroundColor = "red"; window.setTimeout("yourFunction()",10000); which calls yourFunction in 10 seconds to change the colour back.

Searching for UUIDs in text with regex

/^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89AB][0-9a-f]{3}-[0-9a-f]{12}$/i

Gajus' regexp rejects UUID V1-3 and 5, even though they are valid.

What is the final version of the ADT Bundle?

It seems that the version "20140702" of the example link in the question was the final version, because I downloaded this file on the 12th November 2014, i.e. the version from the 2nd of July 2014 was still the latest version on 12th of November. When I try manually all the possible versions/dates between today in this date, then I always get a page with error code "404" (file not found), which indicates that no new version was released since the 12th of November.

Increase distance between text and title on the y-axis

From ggplot2 2.0.0 you can use the margin = argument of element_text() to change the distance between the axis title and the numbers. Set the values of the margin on top, right, bottom, and left side of the element.

ggplot(mpg, aes(cty, hwy)) + geom_point()+
  theme(axis.title.y = element_text(margin = margin(t = 0, r = 20, b = 0, l = 0)))

margin can also be used for other element_text elements (see ?theme), such as axis.text.x, axis.text.y and title.

addition

in order to set the margin for axis titles when the axis has a different position (e.g., with scale_x_...(position = "top"), you'll need a different theme setting - e.g. axis.title.x.top. See https://github.com/tidyverse/ggplot2/issues/4343.

ASP.NET MVC View Engine Comparison

I like ndjango. It is very easy to use and very flexible. You can easily extend view functionality with custom tags and filters. I think that "greatly tied to F#" is rather advantage than disadvantage.

JQuery datepicker not working

Datepicker is not part of jQuery. You have to get jQuery UI to use the datepicker.

How to read all rows from huge table?

At lest in my case the problem was on the client that tries to fetch the results.

Wanted to get a .csv with ALL the results.

I found the solution by using

psql -U postgres -d dbname  -c "COPY (SELECT * FROM T) TO STDOUT WITH DELIMITER ','"

(where dbname the name of the db...) and redirecting to a file.

Fill background color left to right CSS

If you are like me and need to change color of text itself also while in the same time filling the background color check my solution.

Steps to create:

  1. Have two text, one is static colored in color on hover, and the other one in default state color which you will be moving on hover
  2. On hover move wrapper of the not static one text while in the same time move inner text of that wrapper to the opposite direction.
  3. Make sure to add overflow hidden where needed

Good thing about this solution:

  • Support IE9, uses only transform
  • Button (or element you are applying animation) is fluid in width, so no fixed values are being used here

Not so good thing about this solution:

  • A really messy markup, could be solved by using pseudo elements and att(data)?
  • There is some small glitch in animation when having more then one button next to each other, maybe it could be easily solved but I didn't take much time to investigate yet.

Check the pen ---> https://codepen.io/nikolamitic/pen/vpNoNq

<button class="btn btn--animation-from-right">
  <span class="btn__text-static">Cover left</span>
  <div class="btn__text-dynamic">
    <span class="btn__text-dynamic-inner">Cover left</span>
  </div>
</button>

.btn {
  padding: 10px 20px;
  position: relative;

  border: 2px solid #222;
  color: #fff;
  background-color: #222;
  position: relative;

  overflow: hidden;
  cursor: pointer;

  text-transform: uppercase;
  font-family: monospace;
  letter-spacing: -1px;

  [class^="btn__text"] {
    font-size: 24px;
  }

  .btn__text-dynamic,
  .btn__text-dynamic-inner {    
    display: flex;
    justify-content: center;
    align-items: center;

    position: absolute;
    top:0;
    left:0;
    right:0;
    bottom:0;
    z-index: 2;

    transition: all ease 0.5s;
  }

  .btn__text-dynamic {
    background-color: #fff;
    color: #222;

    overflow: hidden;
  }

  &:hover {
    .btn__text-dynamic {
      transform: translateX(-100%);
    }
    .btn__text-dynamic-inner {
      transform: translateX(100%);
    }
  }
}

.btn--animation-from-right {
    &:hover {
    .btn__text-dynamic {
      transform: translateX(100%);
    }
    .btn__text-dynamic-inner {
      transform: translateX(-100%);
    }
  }
}

You can remove .btn--animation-from-right modifier if you want to animate to the left.

jQuery change event on dropdown

The html

<select id="drop"  name="company" class="company btn btn-outline   dropdown-toggle" >
   <option value="demo1">Group Medical</option>
   <option value="demo">Motor Insurance</option>
</select>

Script.js

$("#drop").change(function () {                            
   var category= $('select[name=company]').val() // Here we can get the value of selected item
   alert(category); 
});

How to generate a random integer number from within a range

Here is a formula if you know the max and min values of a range, and you want to generate numbers inclusive in between the range:

r = (rand() % (max + 1 - min)) + min

Remove Primary Key in MySQL

First backup the database. Then drop any foreign key associated with the table. truncate the foreign key table.Truncate the current table. Remove the required primary keys. Use sqlyog or workbench or heidisql or dbeaver or phpmyadmin.

Can't bind to 'ngIf' since it isn't a known property of 'div'

If you are using RC5 then import this:

import { CommonModule } from '@angular/common';  
import { BrowserModule } from '@angular/platform-browser';

and be sure to import CommonModule from the module that is providing your component.

 @NgModule({
    imports: [CommonModule],
    declarations: [MyComponent]
  ...
})
class MyComponentModule {}

MySQL "WITH" clause

Update: MySQL 8.0 is finally getting the feature of common table expressions, including recursive CTEs.

Here's a blog announcing it: http://mysqlserverteam.com/mysql-8-0-labs-recursive-common-table-expressions-in-mysql-ctes/

Below is my earlier answer, which I originally wrote in 2008.


MySQL 5.x does not support queries using the WITH syntax defined in SQL-99, also called Common Table Expressions.

This has been a feature request for MySQL since January 2006: http://bugs.mysql.com/bug.php?id=16244

Other RDBMS products that support common table expressions:

Executing set of SQL queries using batch file?

Different ways:

  1. Using SQL Server Agent (If local instance)
    schedule a job in sql server agent with a new step having type as "T-SQL" then run the job.

  2. Using SQLCMD
    To use SQLCMD refer http://technet.microsoft.com/en-us/library/ms162773.aspx

  3. Using SQLPS
    To use SQLPS refer http://technet.microsoft.com/en-us/library/cc280450.aspx

How to git reset --hard a subdirectory?

What about

subdir=thesubdir
for fn in $(find $subdir); do
  git ls-files --error-unmatch $fn 2>/dev/null >/dev/null;
  if [ "$?" = "1" ]; then
    continue;
  fi
  echo "Restoring $fn";
  git show HEAD:$fn > $fn;
done 

Setting Column width in Apache POI

I answered my problem with a default width for all columns and cells, like below:

int width = 15; // Where width is number of caracters 
sheet.setDefaultColumnWidth(width);

iPhone get SSID without private library

For iOS 13

As from iOS 13 your app also needs Core Location access in order to use the CNCopyCurrentNetworkInfo function unless it configured the current network or has VPN configurations:
excerpt from https://developer.apple.com/documentation/systemconfiguration/1614126-cncopycurrentnetworkinfo?language=objc

So this is what you need (see apple documentation):
- Link the CoreLocation.framework library
- Add location-services as a UIRequiredDeviceCapabilities Key/Value in Info.plist
- Add a NSLocationWhenInUseUsageDescription Key/Value in Info.plist describing why your app requires Core Location
- Add the "Access WiFi Information" entitlement for your app

Now as an Objective-C example, first check if location access has been accepted before reading the network info using CNCopyCurrentNetworkInfo:

- (void)fetchSSIDInfo {
    NSString *ssid = NSLocalizedString(@"not_found", nil);

    if (@available(iOS 13.0, *)) {
        if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusDenied) {
            NSLog(@"User has explicitly denied authorization for this application, or location services are disabled in Settings.");
        } else {
            CLLocationManager* cllocation = [[CLLocationManager alloc] init];
            if(![CLLocationManager locationServicesEnabled] || [CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined){
                [cllocation requestWhenInUseAuthorization];
                usleep(500);
                return [self fetchSSIDInfo];
            }
        }
    }

    NSArray *ifs = (__bridge_transfer id)CNCopySupportedInterfaces();
    id info = nil;
    for (NSString *ifnam in ifs) {
        info = (__bridge_transfer id)CNCopyCurrentNetworkInfo(
            (__bridge CFStringRef)ifnam);

        NSDictionary *infoDict = (NSDictionary *)info;
        for (NSString *key in infoDict.allKeys) {
            if ([key isEqualToString:@"SSID"]) {
                ssid = [infoDict objectForKey:key];
            }
        }
    }        
        ...
    ...
}

Simple timeout in java

    @Singleton
    @AccessTimeout(value=120000)
    public class StatusSingletonBean {
      private String status;
    
      @Lock(LockType.WRITE)
      public void setStatus(String new Status) {
        status = newStatus;
      }
      @Lock(LockType.WRITE)
      @AccessTimeout(value=360000)
      public void doTediousOperation {
        //...
      }
    }
    //The following singleton has a default access timeout value of 60 seconds, specified //using the TimeUnit.SECONDS constant:
    @Singleton
    @AccessTimeout(value=60, timeUnit=SECONDS) 
    public class StatusSingletonBean { 
    //... 
    }  
    //The Java EE 6 Tutorial

//https://docs.oracle.com/javaee/6/tutorial/doc/gipvi.html

Scripting SQL Server permissions

Thanks to Chris for his awesome answer, I took it one step further and automated the process of running those statements (my table had over 8,000 permissions)

if object_id('dbo.tempPermissions') is not null
Drop table dbo.tempPermissions

Create table tempPermissions(ID int identity , Queries Varchar(255))


Insert into tempPermissions(Queries)


select 'GRANT ' + dp.permission_name collate latin1_general_cs_as
   + ' ON ' + s.name + '.' + o.name + ' TO ' + dpr.name 
   FROM sys.database_permissions AS dp
   INNER JOIN sys.objects AS o ON dp.major_id=o.object_id
   INNER JOIN sys.schemas AS s ON o.schema_id = s.schema_id
   INNER JOIN sys.database_principals AS dpr ON dp.grantee_principal_id=dpr.principal_id
   WHERE dpr.name NOT IN ('public','guest')

declare @count int, @max int, @query Varchar(255)
set @count =1
set @max = (Select max(ID) from tempPermissions)
set @query = (Select Queries from tempPermissions where ID = @count)

while(@count < @max)
begin
exec(@query)
set @count += 1
set @query = (Select Queries from tempPermissions where ID = @count)
end

select * from tempPermissions

drop table tempPermissions

additionally to restrict it to a single table add:

  and o.name = 'tablename'

after the WHERE dpr.name NOT IN ('public','guest') and remember to edit the select statement so that it generates statements for the table you want to grant permissions 'TO' Not the table the permissions are coming 'FROM' (which is what the script does).

Remove non-ascii character in string

To use ASCII with accents:

var str = str.replace(/[^\x00-\xFF]/g, "");

Formatting DataBinder.Eval data

Thanks to all. I had been stuck on standard format strings for some time. I also used a custom function in VB.

Mark Up:-

<asp:Label ID="Label3" runat="server" text='<%# Formatlabel(DataBinder.Eval(Container.DataItem, "psWages1D")) %>'/>

Code behind:-

Public Function fLabel(ByVal tval) As String
   fLabel = tval.ToString("#,##0.00%;(#,##0.00%);Zero")
End Function

Tomcat is not deploying my web project from Eclipse

I have the same problem, my solution is:

  • Install WTP Maven integration (don't know if this is necessary)
  • Project -> Run Configurations (Select your tomcat server) -> Run

For a few hours I tried to deploy and start application using Servers window but it didn't worked. My war was not placed in wptwebapps folder, manually deplying war to webapps worked.

Using Run Configurations made my app finally deployable...

There is no argument given that corresponds to the required formal parameter - .NET Error

I received this same error in the following Linq statement regarding DailyReport. The problem was that DailyReport had no default constructor. Apparently, it instantiates the object before populating the properties.

var sums = reports
    .GroupBy(r => r.CountryRegion)
    .Select(cr => new DailyReport
    {
        CountryRegion = cr.Key,
        ProvinceState = "All",
        RecordDate = cr.First().RecordDate,
        Confirmed = cr.Sum(c => c.Confirmed),
        Recovered = cr.Sum(c => c.Recovered),
        Deaths = cr.Sum(c => c.Deaths)
    });

Kendo grid date column not formatting

I found this piece of information and got it to work correctly. The data given to me was in string format so I needed to parse the string using kendo.parseDate before formatting it with kendo.toString.

columns: [
    {
        field: "FirstName",
        title: "FIRST NAME"
    },
    {
        field: "LastName",
        title: "LAST NAME"
    },
    {
        field: "DateOfBirth",
        title: "DATE OF BIRTH",
        template: "#= kendo.toString(kendo.parseDate(DateOfBirth, 'yyyy-MM-dd'), 'MM/dd/yyyy') #"
    },
...


References:

  1. format-date-in-grid
  2. jsfiddle
  3. kendo ui date formatting

Mouseover or hover vue.js

Please take a look at the vue-mouseover package if you are not satisfied how does this code look:

<div
    @mouseover="isMouseover = true"
    @mouseleave="isMouseover = false"
/>

vue-mouseover provides a v-mouseover directive that automaticaly updates the specified data context property when the cursor enters or leaves an HTML element the directive is attached to.

By default in the next example isMouseover property will be true when the cursor is over an HTML element and false otherwise:

<div v-mouseover="isMouseover" />

Also by default isMouseover will be initially assigned when v-mouseover is attached to the div element, so it will not remain unassigned before the first mouseenter/mouseleave event.

You can specify custom values via v-mouseover-value directive:

<div
    v-mouseover="isMouseover"
    v-mouseover-value="customMouseenterValue"/>

or

<div
    v-mouseover="isMouseover"
    v-mouseover-value="{
        mouseenter: customMouseenterValue,
        mouseleave: customMouseleaveValue
    }"
/>

Custom default values can be passed to the package via options object during setup.

REST / SOAP endpoints for a WCF service

This is what i did to make it work. Make sure you put
webHttp automaticFormatSelectionEnabled="true" inside endpoint behaviour.

[ServiceContract]
public interface ITestService
{

    [WebGet(BodyStyle = WebMessageBodyStyle.Bare, UriTemplate = "/product", ResponseFormat = WebMessageFormat.Json)]
    string GetData();
}

public class TestService : ITestService
{
    public string GetJsonData()
    {
        return "I am good...";
    }
}

Inside service model

   <service name="TechCity.Business.TestService">

    <endpoint address="soap" binding="basicHttpBinding" name="SoapTest"
      bindingName="BasicSoap" contract="TechCity.Interfaces.ITestService" />
    <endpoint address="mex"
              contract="IMetadataExchange" binding="mexHttpBinding"/>
    <endpoint behaviorConfiguration="jsonBehavior" binding="webHttpBinding"
              name="Http" contract="TechCity.Interfaces.ITestService" />
    <host>
      <baseAddresses>
        <add baseAddress="http://localhost:8739/test" />
      </baseAddresses>
    </host>
  </service>

EndPoint Behaviour

  <endpointBehaviors>
    <behavior name="jsonBehavior">
      <webHttp automaticFormatSelectionEnabled="true"  />
      <!-- use JSON serialization -->
    </behavior>
  </endpointBehaviors>

Using JAXB to unmarshal/marshal a List<String>

Finally I've solved it using JacksonJaxbJsonProvider It requires few changes in your Spring context.xml and Maven pom.xml

In your Spring context.xml add JacksonJaxbJsonProvider to the <jaxrs:server>:

<jaxrs:server id="restService" address="/resource">
    <jaxrs:providers>
        <bean class="org.codehaus.jackson.jaxrs.JacksonJaxbJsonProvider"/>
    </jaxrs:providers>
</jaxrs:server>

In your Maven pom.xml add:

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-jaxrs</artifactId>
    <version>1.9.0</version>
</dependency>

Adding ASP.NET MVC5 Identity Authentication to an existing project

This is what I did to integrate Identity with an existing database.

  1. Create a sample MVC project with MVC template. This has all the code needed for Identity implementation - Startup.Auth.cs, IdentityConfig.cs, Account Controller code, Manage Controller, Models and related views.

  2. Install the necessary nuget packages for Identity and OWIN. You will get an idea by seeing the references in the sample Project and the answer by @Sam

  3. Copy all these code to your existing project. Please note don't forget to add the "DefaultConnection" connection string for Identity to map to your database. Please check the ApplicationDBContext class in IdentityModel.cs where you will find the reference to "DefaultConnection" connection string.

  4. This is the SQL script I ran on my existing database to create necessary tables:

    USE ["YourDatabse"]
    GO
    /****** Object:  Table [dbo].[AspNetRoles]    Script Date: 16-Aug-15 6:52:25 PM ******/
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    CREATE TABLE [dbo].[AspNetRoles](
    [Id] [nvarchar](128) NOT NULL,
    [Name] [nvarchar](256) NOT NULL,
    CONSTRAINT [PK_dbo.AspNetRoles] PRIMARY KEY CLUSTERED 
    (
      [Id] ASC
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
    ) ON [PRIMARY]
    
    GO
    /****** Object:  Table [dbo].[AspNetUserClaims]    Script Date: 16-Aug-15 6:52:25 PM ******/
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    CREATE TABLE [dbo].[AspNetUserClaims](
       [Id] [int] IDENTITY(1,1) NOT NULL,
       [UserId] [nvarchar](128) NOT NULL,
       [ClaimType] [nvarchar](max) NULL,
       [ClaimValue] [nvarchar](max) NULL,
    CONSTRAINT [PK_dbo.AspNetUserClaims] PRIMARY KEY CLUSTERED 
    (
       [Id] ASC
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
    ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
    
    GO
    /****** Object:  Table [dbo].[AspNetUserLogins]    Script Date: 16-Aug-15 6:52:25 PM ******/
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    CREATE TABLE [dbo].[AspNetUserLogins](
        [LoginProvider] [nvarchar](128) NOT NULL,
        [ProviderKey] [nvarchar](128) NOT NULL,
        [UserId] [nvarchar](128) NOT NULL,
    CONSTRAINT [PK_dbo.AspNetUserLogins] PRIMARY KEY CLUSTERED 
    (
        [LoginProvider] ASC,
        [ProviderKey] ASC,
        [UserId] ASC
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
    ) ON [PRIMARY]
    
    GO
    /****** Object:  Table [dbo].[AspNetUserRoles]    Script Date: 16-Aug-15 6:52:25 PM ******/
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    CREATE TABLE [dbo].[AspNetUserRoles](
       [UserId] [nvarchar](128) NOT NULL,
       [RoleId] [nvarchar](128) NOT NULL,
    CONSTRAINT [PK_dbo.AspNetUserRoles] PRIMARY KEY CLUSTERED 
    (
        [UserId] ASC,
        [RoleId] ASC
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
    ) ON [PRIMARY]
    
    GO
    /****** Object:  Table [dbo].[AspNetUsers]    Script Date: 16-Aug-15 6:52:25 PM ******/
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    CREATE TABLE [dbo].[AspNetUsers](
        [Id] [nvarchar](128) NOT NULL,
        [Email] [nvarchar](256) NULL,
        [EmailConfirmed] [bit] NOT NULL,
        [PasswordHash] [nvarchar](max) NULL,
        [SecurityStamp] [nvarchar](max) NULL,
        [PhoneNumber] [nvarchar](max) NULL,
        [PhoneNumberConfirmed] [bit] NOT NULL,
        [TwoFactorEnabled] [bit] NOT NULL,
        [LockoutEndDateUtc] [datetime] NULL,
        [LockoutEnabled] [bit] NOT NULL,
        [AccessFailedCount] [int] NOT NULL,
        [UserName] [nvarchar](256) NOT NULL,
    CONSTRAINT [PK_dbo.AspNetUsers] PRIMARY KEY CLUSTERED 
    (
        [Id] ASC
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
    ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
    
     GO
     ALTER TABLE [dbo].[AspNetUserClaims]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])
     REFERENCES [dbo].[AspNetUsers] ([Id])
     ON DELETE CASCADE
     GO
     ALTER TABLE [dbo].[AspNetUserClaims] CHECK CONSTRAINT [FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId]
     GO
     ALTER TABLE [dbo].[AspNetUserLogins]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])
     REFERENCES [dbo].[AspNetUsers] ([Id])
     ON DELETE CASCADE
     GO
     ALTER TABLE [dbo].[AspNetUserLogins] CHECK CONSTRAINT [FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId]
     GO
     ALTER TABLE [dbo].[AspNetUserRoles]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId] FOREIGN KEY([RoleId])
     REFERENCES [dbo].[AspNetRoles] ([Id])
     ON DELETE CASCADE
     GO
     ALTER TABLE [dbo].[AspNetUserRoles] CHECK CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId]
     GO
     ALTER TABLE [dbo].[AspNetUserRoles]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])
     REFERENCES [dbo].[AspNetUsers] ([Id])
     ON DELETE CASCADE
     GO
     ALTER TABLE [dbo].[AspNetUserRoles] CHECK CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId]
     GO
    
  5. Check and solve any remaining errors and you are done. Identity will handle the rest :)

Shell script not running, command not found

First:

chmod 777 ./MigrateNshell.sh

Then:

./MigrateNshell.sh

Or, add your program to a directory recognized in your $PATH variable. Example: Path Variable Example Which will then allow you to call your program without ./

Suppress warning messages using mysql from within Terminal, but password written in bash script

it's very simple. this is work for me.

export MYSQL_PWD=password; mysql --user=username -e "statement"

MYSQL_PWD is one of environment variables from mysql. it's default password when connecting to mysqld.

Python, compute list difference

When having a look at TimeComplexity of In-operator, in worst case it works with O(n). Even for Sets.

So when comparing two arrays we'll have a TimeComplexity of O(n) in best case and O(n^2) in worst case.

An alternative (but unfortunately more complex) solution, which works with O(n) in best and worst case is this one:

# Compares the difference of list a and b
# uses a callback function to compare items
def diff(a, b, callback):
  a_missing_in_b = []
  ai = 0
  bi = 0

  a = sorted(a, callback)
  b = sorted(b, callback)

  while (ai < len(a)) and (bi < len(b)):

    cmp = callback(a[ai], b[bi])
    if cmp < 0:
      a_missing_in_b.append(a[ai])
      ai += 1
    elif cmp > 0:
      # Item b is missing in a
      bi += 1
    else:
      # a and b intersecting on this item
      ai += 1
      bi += 1

  # if a and b are not of same length, we need to add the remaining items
  for ai in xrange(ai, len(a)):
    a_missing_in_b.append(a[ai])


  return a_missing_in_b

e.g.

>>> a=[1,2,3]
>>> b=[2,4,6]
>>> diff(a, b, cmp)
[1, 3]

Bash script - variable content as a command to run

In the case where you have multiple variables containing the arguments for a command you're running, and not just a single string, you should not use eval directly, as it will fail in the following case:

function echo_arguments() {
  echo "Argument 1: $1"
  echo "Argument 2: $2"
  echo "Argument 3: $3"
  echo "Argument 4: $4"
}

# Note we are passing 3 arguments to `echo_arguments`, not 4
eval echo_arguments arg1 arg2 "Some arg"

Result:

Argument 1: arg1
Argument 2: arg2
Argument 3: Some
Argument 4: arg

Note that even though "Some arg" was passed as a single argument, eval read it as two.

Instead, you can just use the string as the command itself:

# The regular bash eval works by jamming all its arguments into a string then
# evaluating the string. This function treats its arguments as individual
# arguments to be passed to the command being run.
function eval_command() {
  "$@";
}

Note the difference between the output of eval and the new eval_command function:

eval_command echo_arguments arg1 arg2 "Some arg"

Result:

Argument 1: arg1
Argument 2: arg2
Argument 3: Some arg
Argument 4:

Generating random number between 1 and 10 in Bash Shell Script

To generate random numbers with bash use the $RANDOM internal Bash function. Note that $RANDOM should not be used to generate an encryption key. $RANDOM is generated by using your current process ID (PID) and the current time/date as defined by the number of seconds elapsed since 1970.

 echo $RANDOM % 10 + 1 | bc

Variable might not have been initialized error

You declared them, but you didn't initialize them with a value. Add something like this:

int a = 0;

adb not finding my device / phone (MacOS X)

I had to enable USB debugging (Security settings) developer option in addition to USB debugging in Redmi Note 4.

What’s the difference between "Array()" and "[]" while declaring a JavaScript array?

There is a difference, but there is no difference in that example.

Using the more verbose method: new Array() does have one extra option in the parameters: if you pass a number to the constructor, you will get an array of that length:

x = new Array(5);
alert(x.length); // 5

To illustrate the different ways to create an array:

var a = [],            // these are the same
    b = new Array(),   // a and b are arrays with length 0

    c = ['foo', 'bar'],           // these are the same
    d = new Array('foo', 'bar'),  // c and d are arrays with 2 strings

    // these are different:
    e = [3]             // e.length == 1, e[0] == 3
    f = new Array(3),   // f.length == 3, f[0] == undefined

;

Another difference is that when using new Array() you're able to set the size of the array, which affects the stack size. This can be useful if you're getting stack overflows (Performance of Array.push vs Array.unshift) which is what happens when the size of the array exceeds the size of the stack, and it has to be re-created. So there can actually, depending on the use case, be a performance increase when using new Array() because you can prevent the overflow from happening.

As pointed out in this answer, new Array(5) will not actually add five undefined items to the array. It simply adds space for five items. Be aware that using Array this way makes it difficult to rely on array.length for calculations.

JDBC connection to MSSQL server in windows authentication mode

You need to add sqljdbc_auth.dll in your C:/windows/System32 folder. You can download it from http://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=11774 .

Loop through all the files with a specific extension

Loop through all files ending with: .img, .bin, .txt suffix, and print the file name:

for i in *.img *.bin *.txt;
do
  echo "$i"
done

Or in a recursive manner (find also in all subdirectories):

for i in `find . -type f -name "*.img" -o -name "*.bin" -o -name "*.txt"`;
do
  echo "$i"
done

jQuery DIV click, with anchors

$("div.clickable").click( function(event) { window.location = $(this).attr("url"); event.preventDefault(); });

Efficient way to add spaces between characters in a string

A very pythonic and practical way to do it is by using the string join() method:

str.join(iterable)

The official Python documentations says:

Return a string which is the concatenation of the strings in iterable... The separator between elements is the string providing this method.

How to use it?

Remember: this is a string method.

This method will be applied to the str above, which reflects the string that will be used as separator of the items in the iterable.

Let's have some practical example!

iterable = "BINGO"
separator = " " # A whitespace character.
                # The string to which the method will be applied
separator.join(iterable)
> 'B I N G O'

In practice you would do it like this:

iterable = "BINGO"    
" ".join(iterable)
> 'B I N G O'

But remember that the argument is an iterable, like a string, list, tuple. Although the method returns a string.

iterable = ['B', 'I', 'N', 'G', 'O']    
" ".join(iterable)
> 'B I N G O'

What happens if you use a hyphen as a string instead?

iterable = ['B', 'I', 'N', 'G', 'O']    
"-".join(iterable)
> 'B-I-N-G-O'

a = open("file", "r"); a.readline() output without \n

A solution, can be:

with open("file", "r") as fd:
    lines = fd.read().splitlines()

You get the list of lines without "\r\n" or "\n".

Or, use the classic way:

with open("file", "r") as fd:
    for line in fd:
        line = line.strip()

You read the file, line by line and drop the spaces and newlines.

If you only want to drop the newlines:

with open("file", "r") as fd:
    for line in fd:
        line = line.replace("\r", "").replace("\n", "")

Et voilà.

Note: The behavior of Python 3 is a little different. To mimic this behavior, use io.open.

See the documentation of io.open.

So, you can use:

with io.open("file", "r", newline=None) as fd:
    for line in fd:
        line = line.replace("\n", "")

When the newline parameter is None: lines in the input can end in '\n', '\r', or '\r\n', and these are translated into '\n'.

newline controls how universal newlines works (it only applies to text mode). It can be None, '', '\n', '\r', and '\r\n'. It works as follows:

On input, if newline is None, universal newlines mode is enabled. Lines in the input can end in '\n', '\r', or '\r\n', and these are translated into '\n' before being returned to the caller. If it is '', universal newlines mode is enabled, but line endings are returned to the caller untranslated. If it has any of the other legal values, input lines are only terminated by the given string, and the line ending is returned to the caller untranslated.

Setting button text via javascript

The value of a button element isn't the displayed text, contrary to what happens to input elements of type button.

You can do this :

 b.appendChild(document.createTextNode('test value'));

Demonstration

javax.mail.AuthenticationFailedException: failed to connect, no password specified?

Try to create an javax.mail.Authenticator Object, and send that in with the properties object to the Session object.

Authenticator edit:

You can modify this to accept a username and password and you can store them there, or where ever you want.

public class SmtpAuthenticator extends Authenticator {
public SmtpAuthenticator() {

    super();
}

@Override
public PasswordAuthentication getPasswordAuthentication() {
 String username = "user";
 String password = "password";
    if ((username != null) && (username.length() > 0) && (password != null) 
      && (password.length   () > 0)) {

        return new PasswordAuthentication(username, password);
    }

    return null;
}

In your class where you send the email:

SmtpAuthenticator authentication = new SmtpAuthenticator();
javax.mail.Message msg = new MimeMessage(Session
                    .getDefaultInstance(emailProperties, authenticator));

Action Image MVC3 Razor

Well, you could use @Lucas solution, but there's also another way.

 @Html.ActionLink("Update", "Update", *Your object value*, new { @class = "imgLink"})

Now, add this class on a CSS file or in your page:

.imgLink
{
  background: url(YourImage.png) no-repeat;
}

With that class, any link will have your desired image.

How to create a sticky footer that plays well with Bootstrap 3

   <style type="text/css">

     /* Sticky footer styles
     -------------------------------------------------- */

     html,
     body {
       height: 100%;
       /* The html and body elements cannot have any padding or margin. */
     }

     /* Wrapper for page content to push down footer */
     #wrap {
       min-height: 100%;
       height: auto !important;
       height: 100%;
       /* Negative indent footer by it's height */
       margin: 0 auto -60px;
     }

     /* Set the fixed height of the footer here */
     #push,
     #footer {
       height: 60px;
     }
     #footer {
       background-color: #f5f5f5;
     }

     /* Lastly, apply responsive CSS fixes as necessary */
     @media (max-width: 767px) {
       #footer {
         margin-left: -20px;
         margin-right: -20px;
         padding-left: 20px;
         padding-right: 20px;
       }
     }



     /* Custom page CSS
     -------------------------------------------------- */
     /* Not required for template or sticky footer method. */

     .container {
       width: auto;
       max-width: 680px;
     }
     .container .credit {
       margin: 20px 0;
     }

   </style>


<div id="wrap">

  <!-- Begin page content -->
  <div class="container">
    <div class="page-header">
      <h1>Sticky footer</h1>
    </div>
    <p class="lead">Pin a fixed-height footer to the bottom of the viewport in desktop browsers with this custom HTML and CSS.</p>
    <p>Use <a href="./sticky-footer-navbar.html">the sticky footer</a> with a fixed navbar if need be, too.</p>
  </div>

  <div id="push"></div>
</div>

<div id="footer">
  <div class="container">
    <p class="muted credit">Example courtesy <a href="http://martinbean.co.uk">Martin Bean</a> and <a href="http://ryanfait.com/sticky-footer/">Ryan Fait</a>.</p>
  </div>
</div>

Python 3.4.0 with MySQL database

sudo apt-get install python3-dev
sudo apt-get install libmysqlclient-dev
sudo apt-get install zlib1g-dev
sudo pip3 install mysqlclient

that worked for me!

How to give a time delay of less than one second in excel vba?

I have try this and it works for me:

Private Sub DelayMs(ms As Long)
    Debug.Print TimeValue(Now)
    Application.Wait (Now + (ms * 0.00000001))
    Debug.Print TimeValue(Now)
End Sub

Private Sub test()
    Call DelayMs (2000)  'test code with delay of 2 seconds, see debug window
End Sub

Git update submodules recursively

git submodule update --recursive

You will also probably want to use the --init option which will make it initialize any uninitialized submodules:

git submodule update --init --recursive

Note: in some older versions of Git, if you use the --init option, already-initialized submodules may not be updated. In that case, you should also run the command without --init option.

Multiple simultaneous downloads using Wget?

wget cant download in multiple connections, instead you can try to user other program like aria2.

How to convert a UTF-8 string into Unicode?

What you have seems to be a string incorrectly decoded from another encoding, likely code page 1252, which is US Windows default. Here's how to reverse, assuming no other loss. One loss not immediately apparent is the non-breaking space (U+00A0) at the end of your string that is not displayed. Of course it would be better to read the data source correctly in the first place, but perhaps the data source was stored incorrectly to begin with.

using System;
using System.Text;

class Program
{
    static void Main(string[] args)
    {
        string junk = "déjÃ\xa0";  // Bad Unicode string

        // Turn string back to bytes using the original, incorrect encoding.
        byte[] bytes = Encoding.GetEncoding(1252).GetBytes(junk);

        // Use the correct encoding this time to convert back to a string.
        string good = Encoding.UTF8.GetString(bytes);
        Console.WriteLine(good);
    }
}

Result:

déjà

Selection with .loc in python

This is using dataframes from the pandas package. The "index" part can be either a single index, a list of indices, or a list of booleans. This can be read about in the documentation: https://pandas.pydata.org/pandas-docs/stable/indexing.html

So the index part specifies a subset of the rows to pull out, and the (optional) column_name specifies the column you want to work with from that subset of the dataframe. So if you want to update the 'class' column but only in rows where the class is currently set as 'versicolor', you might do something like what you list in the question:

iris_data.loc[iris_data['class'] == 'versicolor', 'class'] = 'Iris-versicolor'

Getting the current date in SQL Server?

As you are using SQL Server 2008, go with Martin's answer.

If you find yourself needing to do it in SQL Server 2005 where you don't have access to the Date column type, I'd use:

SELECT DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0)

SQLFiddle

Initializing array of structures

There are only two syntaxes at play here.

  1. Plain old array initialisation:

    int x[] = {0, 0}; // x[0] = 0, x[1] = 0
    
  2. A designated initialiser. See the accepted answer to this question: How to initialize a struct in accordance with C programming language standards

    The syntax is pretty self-explanatory though. You can initialise like this:

    struct X {
        int a;
        int b;
    }
    struct X foo = { 0, 1 }; // a = 0, b = 1
    

    or to use any ordering,

    struct X foo = { .b = 0, .a = 1 }; // a = 1, b = 0
    

Correct way to integrate jQuery plugins in AngularJS

i have alreay 2 situations where directives and services/factories didnt play well.

the scenario is that i have (had) a directive that has dependency injection of a service, and from the directive i ask the service to make an ajax call (with $http).

in the end, in both cases the ng-Repeat did not file at all, even when i gave the array an initial value.

i even tried to make a directive with a controller and an isolated-scope

only when i moved everything to a controller and it worked like magic.

example about this here Initialising jQuery plugin (RoyalSlider) in Angular JS

Git:nothing added to commit but untracked files present

If you have already tried using the git add . command to add all your untracked files, make sure you're not under a subfolder of your root project.

git add . will stage all your files under the current subfolder.

Error in strings.xml file in Android

https://developer.android.com/guide/topics/resources/string-resource.html#FormattingAndStyling

Escaping apostrophes and quotes

If you have an apostrophe or a quote in your string, you must either escape it or enclose the whole string in the other type of enclosing quotes. For example, here are some stings that do and don't work:

<string name="good_example">"This'll work"</string>
<string name="good_example_2">This\'ll also work</string>
<string name="bad_example">This doesn't work</string>
<string name="bad_example_2">XML encodings don&apos;t work</string>

Get HTML code using JavaScript with a URL

Use jQuery:

$.ajax({ url: 'your-url', success: function(data) { alert(data); } });

This data is your HTML.

Without jQuery (just JavaScript):

function makeHttpObject() {
  try {return new XMLHttpRequest();}
  catch (error) {}
  try {return new ActiveXObject("Msxml2.XMLHTTP");}
  catch (error) {}
  try {return new ActiveXObject("Microsoft.XMLHTTP");}
  catch (error) {}

  throw new Error("Could not create HTTP request object.");
}

var request = makeHttpObject();
request.open("GET", "your_url", true);
request.send(null);
request.onreadystatechange = function() {
  if (request.readyState == 4)
    alert(request.responseText);
};

How to always show the vertical scrollbar in a browser?

Just a note: In OS X Lion, overflow set to "scroll" behaves more like auto in that scrollbars will only show when being used. They will disappear when not in use. So if any the solutions above don't appear to be working that might be why.

This is what you'll need to fix it:

::-webkit-scrollbar {
  -webkit-appearance: none;
  width: 7px;
}
::-webkit-scrollbar-thumb {
  border-radius: 4px;
  background-color: rgba(0, 0, 0, .5);
  -webkit-box-shadow: 0 0 1px rgba(255, 255, 255, .5);
}

You can style it accordingly.

Python append() vs. + operator on lists, why do these give different results?

To explain "why":

The + operation adds the array elements to the original array. The array.append operation inserts the array (or any object) into the end of the original array, which results in a reference to self in that spot (hence the infinite recursion).

The difference here is that the + operation acts specific when you add an array (it's overloaded like others, see this chapter on sequences) by concatenating the element. The append-method however does literally what you ask: append the object on the right-hand side that you give it (the array or any other object), instead of taking its elements.

An alternative

Use extend() if you want to use a function that acts similar to the + operator (as others have shown here as well). It's not wise to do the opposite: to try to mimic append with the + operator for lists (see my earlier link on why).

Little history

For fun, a little history: the birth of the array module in Python in February 1993. it might surprise you, but arrays were added way after sequences and lists came into existence.

How to load image to WPF in runtime?

In WPF an image is typically loaded from a Stream or an Uri.

BitmapImage supports both and an Uri can even be passed as constructor argument:

var uri = new Uri("http://...");
var bitmap = new BitmapImage(uri);

If the image file is located in a local folder, you would have to use a file:// Uri. You could create such a Uri from a path like this:

var path = Path.Combine(Environment.CurrentDirectory, "Bilder", "sas.png");
var uri = new Uri(path);

If the image file is an assembly resource, the Uri must follow the the Pack Uri scheme:

var uri = new Uri("pack://application:,,,/Bilder/sas.png");

In this case the Visual Studio Build Action for sas.png would have to be Resource.

Once you have created a BitmapImage and also have an Image control like in this XAML

<Image Name="image1" />

you would simply assign the BitmapImage to the Source property of that Image control:

image1.Source = bitmap;

AngularJS UI Router - change url without reloading state

Try something like this

$state.go($state.$current.name, {... $state.params, 'key': newValue}, {notify: false})

how to read all files inside particular folder

Try this It is working for me..

The syntax is GetFiles(string path, string searchPattern);

var filePath = Server.MapPath("~/App_Data/");
string[] filePaths = Directory.GetFiles(@filePath, "*.*");

This code will return all the files inside App_Data folder.

The second parameter . indicates the searchPattern with File Extension where the first * is for file name and second is for format of the file or File Extension like (*.png - any file name with .png format.

Android Studio marks R in red with error message "cannot resolve symbol R", but build succeeds

I had this issue too. I deleted the extra images from my project's drawable folder.

How to declare variable and use it in the same Oracle SQL script?

One possible approach, if you just need to specify a parameter once and replicate it in several places, is to do something like this:

SELECT
  str_size  /* my variable usage */
  , LPAD(TRUNC(DBMS_RANDOM.VALUE * POWER(10, str_size)), str_size, '0') rand
FROM
  dual  /* or any other table, or mixed of joined tables */
  CROSS JOIN (SELECT 8 str_size FROM dual);  /* my variable declaration */

This code generates a string of 8 random digits.

Notice that I create a kind of alias named str_size that holds the constant 8. It is cross-joined to be used more than once in the query.

Converting a string to an integer on Android

You should covert String to float. It is working.

float result = 0;
 if (TextUtils.isEmpty(et.getText().toString()) {
  return;
}

result = Float.parseFloat(et.getText().toString());

tv.setText(result); 

Create autoincrement key in Java DB using NetBeans IDE

If you look at this url: http://java.sun.com/developer/technicalArticles/J2SE/Desktop/javadb/

this part of the schema may be what you are looking for.

 ID          INTEGER NOT NULL 
                PRIMARY KEY GENERATED ALWAYS AS IDENTITY 
                (START WITH 1, INCREMENT BY 1),

Center align with table-cell

Here is a good starting point.

HTML:

<div class="containing-table">
    <div class="centre-align">
        <div class="content"></div>
    </div>
</div>

CSS:

.containing-table {
    display: table;
    width: 100%;
    height: 400px; /* for demo only */
    border: 1px dotted blue;
}
.centre-align {
    padding: 10px;
    border: 1px dashed gray;
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}
.content {
    width: 50px;
    height: 50px;
    background-color: red;
    display: inline-block;
    vertical-align: top; /* Removes the extra white space below the baseline */
}

See demo at: http://jsfiddle.net/audetwebdesign/jSVyY/

.containing-table establishes the width and height context for .centre-align (the table-cell).

You can apply text-align and vertical-align to alter .centre-align as needed.

Note that .content needs to use display: inline-block if it is to be centered horizontally using the text-align property.

How do I get started with Node.js

Use the source, Luke.

No, but seriously I found that building Node.js from source, running the tests, and looking at the benchmarks did get me on the right track. From there, the .js files in the lib directory are a good place to look, especially the file http.js.

Update: I wrote this answer over a year ago, and since that time there has an explosion in the number of great resources available for people learning Node.js. Though I still believe diving into the source is worthwhile, I think that there are now better ways to get started. I would suggest some of the books on Node.js that are starting to come out.

How to check if a class inherits another class without instantiating it?

To check for assignability, you can use the Type.IsAssignableFrom method:

typeof(SomeType).IsAssignableFrom(typeof(Derived))

This will work as you expect for type-equality, inheritance-relationships and interface-implementations but not when you are looking for 'assignability' across explicit / implicit conversion operators.

To check for strict inheritance, you can use Type.IsSubclassOf:

typeof(Derived).IsSubclassOf(typeof(SomeType))

How to parse XML to R data frame

Use xpath more directly for both performance and clarity.

time_path <- "//start-valid-time"
temp_path <- "//temperature[@type='hourly']/value"

df <- data.frame(
    latitude=data[["number(//point/@latitude)"]],
    longitude=data[["number(//point/@longitude)"]],
    start_valid_time=sapply(data[time_path], xmlValue),
    hourly_temperature=as.integer(sapply(data[temp_path], as, "integer"))

leading to

> head(df, 2)
  latitude longitude          start_valid_time hourly_temperature
1    29.81    -82.42 2014-02-14T18:00:00-05:00                 60
2    29.81    -82.42 2014-02-14T19:00:00-05:00                 55

Calling a method inside another method in same class

It is not recursion, it is overloading. The two add methods (the one in your snippet, and the one "provided" by ArrayList that you are extending) are not the same method, cause they are declared with different parameters.

Invalid shorthand property initializer

Use : instead of =

see the example below that gives an error

app.post('/mews', (req, res) => {
if (isValidMew(req.body)) {
    // insert into db
    const mew = {
        name = filter.clean(req.body.name.toString()),
        content = filter.clean(req.body.content.toString()),
        created: new Date()
    };

That gives Syntex Error: invalid shorthand proprty initializer.

Then i replace = with : that's solve this error.

app.post('/mews', (req, res) => {
if (isValidMew(req.body)) {
    // insert into db
    const mew = {
        name: filter.clean(req.body.name.toString()),
        content: filter.clean(req.body.content.toString()),
        created: new Date()
    };

Base64: java.lang.IllegalArgumentException: Illegal character

The Base64.Encoder.encodeToString method automatically uses the ISO-8859-1 character set.

For an encryption utility I am writing, I took the input string of cipher text and Base64 encoded it for transmission, then reversed the process. Relevant parts shown below. NOTE: My file.encoding property is set to ISO-8859-1 upon invocation of the JVM so that may also have a bearing.

static String getBase64EncodedCipherText(String cipherText) {
    byte[] cText = cipherText.getBytes();
    // return an ISO-8859-1 encoded String
    return Base64.getEncoder().encodeToString(cText);
}

static String getBase64DecodedCipherText(String encodedCipherText) throws IOException {
    return new String((Base64.getDecoder().decode(encodedCipherText)));
}

public static void main(String[] args) {
    try {
        String cText = getRawCipherText(null, "Hello World of Encryption...");

        System.out.println("Text to encrypt/encode: Hello World of Encryption...");
        // This output is a simple sanity check to display that the text
        // has indeed been converted to a cipher text which 
        // is unreadable by all but the most intelligent of programmers.
        // It is absolutely inhuman of me to do such a thing, but I am a
        // rebel and cannot be trusted in any way.  Please look away.
        System.out.println("RAW CIPHER TEXT: " + cText);
        cText = getBase64EncodedCipherText(cText);
        System.out.println("BASE64 ENCODED: " + cText);
        // There he goes again!!
        System.out.println("BASE64 DECODED:  " + getBase64DecodedCipherText(cText));
        System.out.println("DECODED CIPHER TEXT: " + decodeRawCipherText(null, getBase64DecodedCipherText(cText)));
    } catch (Exception e) {
        e.printStackTrace();
    }

}

The output looks like:

Text to encrypt/encode: Hello World of Encryption...
RAW CIPHER TEXT: q$;?C?l??<8??U???X[7l
BASE64 ENCODED: HnEPJDuhQ+qDbInUCzw4gx0VDqtVwef+WFs3bA==
BASE64 DECODED:  q$;?C?l??<8??U???X[7l``
DECODED CIPHER TEXT: Hello World of Encryption...

How to send a Post body in the HttpClient request in Windows Phone 8?

I implemented it in the following way. I wanted a generic MakeRequest method that could call my API and receive content for the body of the request - and also deserialise the response into the desired type. I create a Dictionary<string, string> object to house the content to be submitted, and then set the HttpRequestMessage Content property with it:

Generic method to call the API:

    private static T MakeRequest<T>(string httpMethod, string route, Dictionary<string, string> postParams = null)
    {
        using (var client = new HttpClient())
        {
            HttpRequestMessage requestMessage = new HttpRequestMessage(new HttpMethod(httpMethod), $"{_apiBaseUri}/{route}");

            if (postParams != null)
                requestMessage.Content = new FormUrlEncodedContent(postParams);   // This is where your content gets added to the request body


            HttpResponseMessage response = client.SendAsync(requestMessage).Result;

            string apiResponse = response.Content.ReadAsStringAsync().Result;
            try
            {
                // Attempt to deserialise the reponse to the desired type, otherwise throw an expetion with the response from the api.
                if (apiResponse != "")
                    return JsonConvert.DeserializeObject<T>(apiResponse);
                else
                    throw new Exception();
            }
            catch (Exception ex)
            {
                throw new Exception($"An error ocurred while calling the API. It responded with the following message: {response.StatusCode} {response.ReasonPhrase}");
            }
        }
    }

Call the method:

    public static CardInformation ValidateCard(string cardNumber, string country = "CAN")
    { 
        // Here you create your parameters to be added to the request content
        var postParams = new Dictionary<string, string> { { "cardNumber", cardNumber }, { "country", country } };
        // make a POST request to the "cards" endpoint and pass in the parameters
        return MakeRequest<CardInformation>("POST", "cards", postParams);
    }

No module named _sqlite3

I had the same problem (building python2.5 from source on Ubuntu Lucid), and import sqlite3 threw this same exception. I've installed libsqlite3-dev from the package manager, recompiled python2.5, and then the import worked.

Google Chromecast sender error if Chromecast extension is not installed or using incognito

If you want to temporarily get rid of these console errors (like I did) you can install the extension here: https://chrome.google.com/webstore/detail/google-cast/boadgeojelhgndaghljhdicfkmllpafd/reviews?hl=en

I left a review asking for a fix. You can also do a bug report via the extension (after you install it) here. Instructions for doing so are here: https://support.google.com/chromecast/answer/3187017?hl=en

I hope Google gets on this. I need my console to show my errors, etc. Not theirs.

Running Google Maps v2 on the Android emulator

I am able to have my emulator to run my app with Google Map V.2 (with Google Play Service V.4). I followed steps that others suggested with some failures, however I learned from it and somehow make it work. This is how:

  1. First of all: You must have coded your map app. correctly with all the appropriate permissions setup in your metafile XML, and have Google Play Services APK part of your app. To verify this is true, you must run your app on REAL device and know it works with its map there. Then you can proceed to process your emulator as shown below.

  2. Create a new emulator, or use your existing emulator with specs:

    • Target Name = Android 4.1.2
    • API Level = 16
    • CPU = Any. However, I found ARM is much faster/responsive than x86
    • Have enough RAM memory and space MB
  3. Run you emulator (your target emulator must be running!)

  4. Download the following APKs (available via dropbox per 4/2/2013) to your local directory (scan for virus!):

  5. Install these two APK into your running (target) emulator with ADB command:

    DOS/Console Prompt> adb -e install [path-to-APK-file]

    NOTE: Possibly, you have had these APKs installed in your emulator during this trial-error, and need to re-install for some reason. You must uninstall them first by: adb -e uninstall (com.google.android.gms or com.android.vending)

  6. Here, it is where things could get tricky. You think you were done, but when you open your app with Map again, but all you get is an error saying something in the form of: "Google Play services out of date. Requires 2012100 but found 2010110", and may see a button to "Update" Google Play. If this is the case, do NOT attempt to click the update button since it won't do anything. I got this error too, and I resolved it by both of these additional steps:

    • Clean-rebuild-reinstall my app into the emulator
    • Shutdown my emulator and re-start it.
  7. That's it, it works now nicely.

Client on Node.js: Uncaught ReferenceError: require is not defined

ES6: In HTML, include the main JavaScript file using attribute type="module" (browser support):

<script type="module" src="script.js"></script>

And in the script.js file, include another file like this:

import { hello } from './module.js';
...
// alert(hello());

Inside the included file (module.js), you must export the function/class that you will import:

export function hello() {
    return "Hello World";
}

A working example is here. More information is here.

CRON job to run on the last day of the month

There's a slightly shorter method that can be used similar to one of the ones above. That is:

[ $(date -d +1day +%d) -eq 1 ] && echo "last day of month"

Also, the crontab entry could be update to only check on the 28th to 31st as it's pointless running it the other days of the month. Which would give you:

0 23 28-31 * * [ $(date -d +1day +%d) -eq 1 ] && myscript.sh

How to connect wireless network adapter to VMWare workstation?

Since there is only one WiFi hardware on the computer its not possible to connect one WiFi hardware to multiple WiFi networks, if you want to that I think you have to map WiFi hardware to guest OS and how host you'll have to use some other hardware (may be Ethernet) but I'm sure that it will work in that way as no VM software allow us to allocate Hardware to Guest except for USB, you can also get USB WiFI and allocate that to VM only.

.keyCode vs. .which

look at this: https://developer.mozilla.org/en-US/docs/Web/API/event.keyCode

In a keypress event, the Unicode value of the key pressed is stored in either the keyCode or charCode property, never both. If the key pressed generates a character (e.g. 'a'), charCode is set to the code of that character, respecting the letter case. (i.e. charCode takes into account whether the shift key is held down). Otherwise, the code of the pressed key is stored in keyCode. keyCode is always set in the keydown and keyup events. In these cases, charCode is never set. To get the code of the key regardless of whether it was stored in keyCode or charCode, query the which property. Characters entered through an IME do not register through keyCode or charCode.

SQL Server equivalent to Oracle's CREATE OR REPLACE VIEW

You can use 'IF EXISTS' to check if the view exists and drop if it does.

IF EXISTS (SELECT TABLE_NAME FROM INFORMATION_SCHEMA.VIEWS
        WHERE TABLE_NAME = 'MyView')
    DROP VIEW MyView
GO

CREATE VIEW MyView
AS 
     ....
GO

Can I use an image from my local file system as background in HTML?

Jeff Bridgman is correct. All you need is
background: url('pic.jpg')
and this assumes that pic is in the same folder as your html.

Also, Roberto's answer works fine. Tested in Firefox, and IE. Thanks to Raptor for adding formatting that displays full picture fit to screen, and without scrollbars... In a folder f, on the desktop is this html and a picture, pic.jpg, using your userid. Make those substitutions in the below:

<html>
<head>
    <style>
        body {

        background: url('file:///C:/Users/userid/desktop/f/pic.jpg') no-repeat center center fixed;

        background-size: cover; /* for IE9+, Safari 4.1+, Chrome 3.0+, Firefox 3.6+ */
        -webkit-background-size: cover; /* for Safari 3.0 - 4.0 , Chrome 1.0 - 3.0 */
        -moz-background-size: cover; /* optional for Firefox 3.6 */ 
        -o-background-size: cover; /* for Opera 9.5 */
        margin: 0; /* to remove the default white margin of body */
        padding: 0; /* to remove the default white margin of body */
        overflow: hidden;
             }
    </style>
</head>
<body>
hello
</body>
</html>

Exit single-user mode

I had the same problem, and the session_id to kill was found using this query:

Select request_session_id From sys.dm_tran_locks Where resource_database_id=DB_ID('BI_DB_Rep');

how to remove "," from a string in javascript

You can try something like:

var str = "a,d,k";
str.replace(/,/g, "");

Request Permission for Camera and Library in iOS 10 - Info.plist

I wrote an extension that takes into account all possible cases:

  • If access is allowed, then the code onAccessHasBeenGranted will be run.
  • If access is not determined, then requestAuthorization(_:) will be called.
  • If the user has denied your app photo library access, then the user will be shown a window offering to go to settings and allow access. In this window, the "Cancel" and "Settings" buttons will be available to him. When he presses the "settings" button, your application settings will open.

Usage example:

PHPhotoLibrary.execute(controller: self, onAccessHasBeenGranted: {
    // access granted... 
})

Extension code:

import Photos
import UIKit

public extension PHPhotoLibrary {

   static func execute(controller: UIViewController,
                       onAccessHasBeenGranted: @escaping () -> Void,
                       onAccessHasBeenDenied: (() -> Void)? = nil) {

      let onDeniedOrRestricted = onAccessHasBeenDenied ?? {
         let alert = UIAlertController(
            title: "We were unable to load your album groups. Sorry!",
            message: "You can enable access in Privacy Settings",
            preferredStyle: .alert)
         alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
         alert.addAction(UIAlertAction(title: "Settings", style: .default, handler: { _ in
            if let settingsURL = URL(string: UIApplication.openSettingsURLString) {
               UIApplication.shared.open(settingsURL)
            }
         }))
         controller.present(alert, animated: true)
      }

      let status = PHPhotoLibrary.authorizationStatus()
      switch status {
      case .notDetermined:
         onNotDetermined(onDeniedOrRestricted, onAccessHasBeenGranted)
      case .denied, .restricted:
         onDeniedOrRestricted()
      case .authorized:
         onAccessHasBeenGranted()
      @unknown default:
         fatalError("PHPhotoLibrary::execute - \"Unknown case\"")
      }
   }

}

private func onNotDetermined(_ onDeniedOrRestricted: @escaping (()->Void), _ onAuthorized: @escaping (()->Void)) {
   PHPhotoLibrary.requestAuthorization({ status in
      switch status {
      case .notDetermined:
         onNotDetermined(onDeniedOrRestricted, onAuthorized)
      case .denied, .restricted:
         onDeniedOrRestricted()
      case .authorized:
         onAuthorized()
      @unknown default:
         fatalError("PHPhotoLibrary::execute - \"Unknown case\"")
      }
   })
}

How to cd into a directory with space in the name?

ok i spent some frustrating time with this problem too. My little guide.

Open desktop for example. If you didnt switch your disc in cmd, type:

cd desktop

Now if you want to display subfolders:

cd, make 1 spacebar, and press tab 2 times

Now if you want to enter directory/file with SPACE IN NAME. Lets open some file name f.g., to open it we need to type:

cd file\ name

p.s. notice this space after slash :)

How to style child components from parent component's CSS file?

Since /deep/, >>>, and ::ng-deep are all deprecated. The best approach is to use the following in your child component styling

:host-context(.theme-light) h2 {
  background-color: #eef;
}

This will look for the theme-light in any of the ancestors of your child component. See docs here: https://angular.io/guide/component-styles#host-context

how to parse json using groovy

That response is a Map, with a single element with key '212315952136472'. There's no 'data' key in the Map. If you want to loop through all entries, use something like this:

JSONObject userJson = JSON.parse(jsonResponse)
userJson.each { id, data -> println data.link }

If you know it's a single-element Map then you can directly access the link:

def data = userJson.values().iterator().next()
String link = data.link

And if you knew the id (e.g. if you used it to make the request) then you can access the value more concisely:

String id = '212315952136472'
...
String link = userJson[id].link

Truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()

You need to use bitwise operators | instead of or and & instead of and in pandas, you can't simply use the bool statements from python.

For much complex filtering create a mask and apply the mask on the dataframe.
Put all your query in the mask and apply it.
Suppose,

mask = (df["col1"]>=df["col2"]) & (stock["col1"]<=df["col2"])
df_new = df[mask]

Setting default permissions for newly created files and sub-directories under a directory in Linux?

in your shell script (or .bashrc) you may use somthing like:

umask 022

umask is a command that determines the settings of a mask that controls how file permissions are set for newly created files.

MySQL - select data from database between two dates

Maybe use in between better. It worked for me to get range then filter it

Detect if PHP session exists

I use a combined version:

if(session_id() == '' || !isset($_SESSION)) {
    // session isn't started
    session_start();
}

Counting null and non-null values in a single query

In my case I wanted the "null distribution" amongst multiple columns:

SELECT
       (CASE WHEN a IS NULL THEN 'NULL' ELSE 'NOT-NULL' END) AS a_null,
       (CASE WHEN b IS NULL THEN 'NULL' ELSE 'NOT-NULL' END) AS b_null,
       (CASE WHEN c IS NULL THEN 'NULL' ELSE 'NOT-NULL' END) AS c_null,
       ...
       count(*)
FROM us
GROUP BY 1, 2, 3,...
ORDER BY 1, 2, 3,...

As per the '...' it is easily extendable to more columns, as many as needed

How to make the division of 2 ints produce a float instead of another int?

Cast one of the integers/both of the integer to float to force the operation to be done with floating point Math. Otherwise integer Math is always preferred. So:

1. v = (float)s / t;
2. v = (float)s / (float)t;

How can I check whether a variable is defined in Node.js?

For easy tasks I often simply do it like:

var undef;

// Fails on undefined variables
if (query !== undef) {
    // variable is defined
} else {
    // else do this
}

Or if you simply want to check for a nulled value too..

var undef;

// Fails on undefined variables
// And even fails on null values
if (query != undef) {
    // variable is defined and not null
} else {
    // else do this
}

Bash script plugin for Eclipse?

I tried ShellEd, but it wouldn't recognize any of my shell scripts, even when I restarted eclipse. I added the ksh interpreter and made it the default, but it made no diffence.

Finally, I closed the tab that was open and displaying a ksh file, then re-opened it. That made it work correctly. After having used it for a while, I can also recommend it.

How do I pretty-print existing JSON data with Java?

Use gson. https://www.mkyong.com/java/how-to-enable-pretty-print-json-output-gson/

Gson gson = new GsonBuilder().setPrettyPrinting().create();
String json = gson.toJson(my_bean);

output

{
  "name": "mkyong",
  "age": 35,
  "position": "Founder",
  "salary": 10000,
  "skills": [
    "java",
    "python",
    "shell"
  ]
}

:last-child not working as expected?

The last-child selector is used to select the last child element of a parent. It cannot be used to select the last child element with a specific class under a given parent element.

The other part of the compound selector (which is attached before the :last-child) specifies extra conditions which the last child element must satisfy in-order for it to be selected. In the below snippet, you would see how the selected elements differ depending on the rest of the compound selector.

_x000D_
_x000D_
.parent :last-child{ /* this will select all elements which are last child of .parent */_x000D_
  font-weight: bold;_x000D_
}_x000D_
_x000D_
.parent div:last-child{ /* this will select the last child of .parent only if it is a div*/_x000D_
  background: crimson;_x000D_
}_x000D_
_x000D_
.parent div.child-2:last-child{ /* this will select the last child of .parent only if it is a div and has the class child-2*/_x000D_
  color: beige;_x000D_
}
_x000D_
<div class='parent'>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child'>Child</div>_x000D_
  <div>Child w/o class</div>_x000D_
</div>_x000D_
<div class='parent'>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child-2'>Child w/o class</div>_x000D_
</div>_x000D_
<div class='parent'>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child'>Child</div>_x000D_
  <div class='child'>Child</div>_x000D_
  <p>Child w/o class</p>_x000D_
</div>
_x000D_
_x000D_
_x000D_


To answer your question, the below would style the last child li element with background color as red.

li:last-child{
    background-color: red;
}

But the following selector would not work for your markup because the last-child does not have the class='complete' even though it is an li.

li.complete:last-child{
    background-color: green;
}

It would have worked if (and only if) the last li in your markup also had class='complete'.


To address your query in the comments:

@Harry I find it rather odd that: .complete:last-of-type does not work, yet .complete:first-of-type does work, regardless of it's position it's parents element. Thanks for your help.

The selector .complete:first-of-type works in the fiddle because it (that is, the element with class='complete') is still the first element of type li within the parent. Try to add <li>0</li> as the first element under the ul and you will find that first-of-type also flops. This is because the first-of-type and last-of-type selectors select the first/last element of each type under the parent.

Refer to the answer posted by BoltClock, in this thread for more details about how the selector works. That is as comprehensive as it gets :)

Get URL of ASP.Net Page in code-behind

Use this:

Request.Url.AbsoluteUri

That will get you the full path (including http://...)

Getting value of HTML Checkbox from onclick/onchange events

Use this

<input type="checkbox" onclick="onClickHandler()" id="box" />

<script>
function onClickHandler(){
    var chk=document.getElementById("box").value;

    //use this value

}
</script>

Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

If you think a 64-bit DIV instruction is a good way to divide by two, then no wonder the compiler's asm output beat your hand-written code, even with -O0 (compile fast, no extra optimization, and store/reload to memory after/before every C statement so a debugger can modify variables).

See Agner Fog's Optimizing Assembly guide to learn how to write efficient asm. He also has instruction tables and a microarch guide for specific details for specific CPUs. See also the tag wiki for more perf links.

See also this more general question about beating the compiler with hand-written asm: Is inline assembly language slower than native C++ code?. TL:DR: yes if you do it wrong (like this question).

Usually you're fine letting the compiler do its thing, especially if you try to write C++ that can compile efficiently. Also see is assembly faster than compiled languages?. One of the answers links to these neat slides showing how various C compilers optimize some really simple functions with cool tricks. Matt Godbolt's CppCon2017 talk “What Has My Compiler Done for Me Lately? Unbolting the Compiler's Lid” is in a similar vein.


even:
    mov rbx, 2
    xor rdx, rdx
    div rbx

On Intel Haswell, div r64 is 36 uops, with a latency of 32-96 cycles, and a throughput of one per 21-74 cycles. (Plus the 2 uops to set up RBX and zero RDX, but out-of-order execution can run those early). High-uop-count instructions like DIV are microcoded, which can also cause front-end bottlenecks. In this case, latency is the most relevant factor because it's part of a loop-carried dependency chain.

shr rax, 1 does the same unsigned division: It's 1 uop, with 1c latency, and can run 2 per clock cycle.

For comparison, 32-bit division is faster, but still horrible vs. shifts. idiv r32 is 9 uops, 22-29c latency, and one per 8-11c throughput on Haswell.


As you can see from looking at gcc's -O0 asm output (Godbolt compiler explorer), it only uses shifts instructions. clang -O0 does compile naively like you thought, even using 64-bit IDIV twice. (When optimizing, compilers do use both outputs of IDIV when the source does a division and modulus with the same operands, if they use IDIV at all)

GCC doesn't have a totally-naive mode; it always transforms through GIMPLE, which means some "optimizations" can't be disabled. This includes recognizing division-by-constant and using shifts (power of 2) or a fixed-point multiplicative inverse (non power of 2) to avoid IDIV (see div_by_13 in the above godbolt link).

gcc -Os (optimize for size) does use IDIV for non-power-of-2 division, unfortunately even in cases where the multiplicative inverse code is only slightly larger but much faster.


Helping the compiler

(summary for this case: use uint64_t n)

First of all, it's only interesting to look at optimized compiler output. (-O3). -O0 speed is basically meaningless.

Look at your asm output (on Godbolt, or see How to remove "noise" from GCC/clang assembly output?). When the compiler doesn't make optimal code in the first place: Writing your C/C++ source in a way that guides the compiler into making better code is usually the best approach. You have to know asm, and know what's efficient, but you apply this knowledge indirectly. Compilers are also a good source of ideas: sometimes clang will do something cool, and you can hand-hold gcc into doing the same thing: see this answer and what I did with the non-unrolled loop in @Veedrac's code below.)

This approach is portable, and in 20 years some future compiler can compile it to whatever is efficient on future hardware (x86 or not), maybe using new ISA extension or auto-vectorizing. Hand-written x86-64 asm from 15 years ago would usually not be optimally tuned for Skylake. e.g. compare&branch macro-fusion didn't exist back then. What's optimal now for hand-crafted asm for one microarchitecture might not be optimal for other current and future CPUs. Comments on @johnfound's answer discuss major differences between AMD Bulldozer and Intel Haswell, which have a big effect on this code. But in theory, g++ -O3 -march=bdver3 and g++ -O3 -march=skylake will do the right thing. (Or -march=native.) Or -mtune=... to just tune, without using instructions that other CPUs might not support.

My feeling is that guiding the compiler to asm that's good for a current CPU you care about shouldn't be a problem for future compilers. They're hopefully better than current compilers at finding ways to transform code, and can find a way that works for future CPUs. Regardless, future x86 probably won't be terrible at anything that's good on current x86, and the future compiler will avoid any asm-specific pitfalls while implementing something like the data movement from your C source, if it doesn't see something better.

Hand-written asm is a black-box for the optimizer, so constant-propagation doesn't work when inlining makes an input a compile-time constant. Other optimizations are also affected. Read https://gcc.gnu.org/wiki/DontUseInlineAsm before using asm. (And avoid MSVC-style inline asm: inputs/outputs have to go through memory which adds overhead.)

In this case: your n has a signed type, and gcc uses the SAR/SHR/ADD sequence that gives the correct rounding. (IDIV and arithmetic-shift "round" differently for negative inputs, see the SAR insn set ref manual entry). (IDK if gcc tried and failed to prove that n can't be negative, or what. Signed-overflow is undefined behaviour, so it should have been able to.)

You should have used uint64_t n, so it can just SHR. And so it's portable to systems where long is only 32-bit (e.g. x86-64 Windows).


BTW, gcc's optimized asm output looks pretty good (using unsigned long n): the inner loop it inlines into main() does this:

 # from gcc5.4 -O3  plus my comments

 # edx= count=1
 # rax= uint64_t n

.L9:                   # do{
    lea    rcx, [rax+1+rax*2]   # rcx = 3*n + 1
    mov    rdi, rax
    shr    rdi         # rdi = n>>1;
    test   al, 1       # set flags based on n%2 (aka n&1)
    mov    rax, rcx
    cmove  rax, rdi    # n= (n%2) ? 3*n+1 : n/2;
    add    edx, 1      # ++count;
    cmp    rax, 1
    jne   .L9          #}while(n!=1)

  cmp/branch to update max and maxi, and then do the next n

The inner loop is branchless, and the critical path of the loop-carried dependency chain is:

  • 3-component LEA (3 cycles)
  • cmov (2 cycles on Haswell, 1c on Broadwell or later).

Total: 5 cycle per iteration, latency bottleneck. Out-of-order execution takes care of everything else in parallel with this (in theory: I haven't tested with perf counters to see if it really runs at 5c/iter).

The FLAGS input of cmov (produced by TEST) is faster to produce than the RAX input (from LEA->MOV), so it's not on the critical path.

Similarly, the MOV->SHR that produces CMOV's RDI input is off the critical path, because it's also faster than the LEA. MOV on IvyBridge and later has zero latency (handled at register-rename time). (It still takes a uop, and a slot in the pipeline, so it's not free, just zero latency). The extra MOV in the LEA dep chain is part of the bottleneck on other CPUs.

The cmp/jne is also not part of the critical path: it's not loop-carried, because control dependencies are handled with branch prediction + speculative execution, unlike data dependencies on the critical path.


Beating the compiler

GCC did a pretty good job here. It could save one code byte by using inc edx instead of add edx, 1, because nobody cares about P4 and its false-dependencies for partial-flag-modifying instructions.

It could also save all the MOV instructions, and the TEST: SHR sets CF= the bit shifted out, so we can use cmovc instead of test / cmovz.

 ### Hand-optimized version of what gcc does
.L9:                       #do{
    lea     rcx, [rax+1+rax*2] # rcx = 3*n + 1
    shr     rax, 1         # n>>=1;    CF = n&1 = n%2
    cmovc   rax, rcx       # n= (n&1) ? 3*n+1 : n/2;
    inc     edx            # ++count;
    cmp     rax, 1
    jne     .L9            #}while(n!=1)

See @johnfound's answer for another clever trick: remove the CMP by branching on SHR's flag result as well as using it for CMOV: zero only if n was 1 (or 0) to start with. (Fun fact: SHR with count != 1 on Nehalem or earlier causes a stall if you read the flag results. That's how they made it single-uop. The shift-by-1 special encoding is fine, though.)

Avoiding MOV doesn't help with the latency at all on Haswell (Can x86's MOV really be "free"? Why can't I reproduce this at all?). It does help significantly on CPUs like Intel pre-IvB, and AMD Bulldozer-family, where MOV is not zero-latency. The compiler's wasted MOV instructions do affect the critical path. BD's complex-LEA and CMOV are both lower latency (2c and 1c respectively), so it's a bigger fraction of the latency. Also, throughput bottlenecks become an issue, because it only has two integer ALU pipes. See @johnfound's answer, where he has timing results from an AMD CPU.

Even on Haswell, this version may help a bit by avoiding some occasional delays where a non-critical uop steals an execution port from one on the critical path, delaying execution by 1 cycle. (This is called a resource conflict). It also saves a register, which may help when doing multiple n values in parallel in an interleaved loop (see below).

LEA's latency depends on the addressing mode, on Intel SnB-family CPUs. 3c for 3 components ([base+idx+const], which takes two separate adds), but only 1c with 2 or fewer components (one add). Some CPUs (like Core2) do even a 3-component LEA in a single cycle, but SnB-family doesn't. Worse, Intel SnB-family standardizes latencies so there are no 2c uops, otherwise 3-component LEA would be only 2c like Bulldozer. (3-component LEA is slower on AMD as well, just not by as much).

So lea rcx, [rax + rax*2] / inc rcx is only 2c latency, faster than lea rcx, [rax + rax*2 + 1], on Intel SnB-family CPUs like Haswell. Break-even on BD, and worse on Core2. It does cost an extra uop, which normally isn't worth it to save 1c latency, but latency is the major bottleneck here and Haswell has a wide enough pipeline to handle the extra uop throughput.

Neither gcc, icc, nor clang (on godbolt) used SHR's CF output, always using an AND or TEST. Silly compilers. :P They're great pieces of complex machinery, but a clever human can often beat them on small-scale problems. (Given thousands to millions of times longer to think about it, of course! Compilers don't use exhaustive algorithms to search for every possible way to do things, because that would take too long when optimizing a lot of inlined code, which is what they do best. They also don't model the pipeline in the target microarchitecture, at least not in the same detail as IACA or other static-analysis tools; they just use some heuristics.)


Simple loop unrolling won't help; this loop bottlenecks on the latency of a loop-carried dependency chain, not on loop overhead / throughput. This means it would do well with hyperthreading (or any other kind of SMT), since the CPU has lots of time to interleave instructions from two threads. This would mean parallelizing the loop in main, but that's fine because each thread can just check a range of n values and produce a pair of integers as a result.

Interleaving by hand within a single thread might be viable, too. Maybe compute the sequence for a pair of numbers in parallel, since each one only takes a couple registers, and they can all update the same max / maxi. This creates more instruction-level parallelism.

The trick is deciding whether to wait until all the n values have reached 1 before getting another pair of starting n values, or whether to break out and get a new start point for just one that reached the end condition, without touching the registers for the other sequence. Probably it's best to keep each chain working on useful data, otherwise you'd have to conditionally increment its counter.


You could maybe even do this with SSE packed-compare stuff to conditionally increment the counter for vector elements where n hadn't reached 1 yet. And then to hide the even longer latency of a SIMD conditional-increment implementation, you'd need to keep more vectors of n values up in the air. Maybe only worth with 256b vector (4x uint64_t).

I think the best strategy to make detection of a 1 "sticky" is to mask the vector of all-ones that you add to increment the counter. So after you've seen a 1 in an element, the increment-vector will have a zero, and +=0 is a no-op.

Untested idea for manual vectorization

# starting with YMM0 = [ n_d, n_c, n_b, n_a ]  (64-bit elements)
# ymm4 = _mm256_set1_epi64x(1):  increment vector
# ymm5 = all-zeros:  count vector

.inner_loop:
    vpaddq    ymm1, ymm0, xmm0
    vpaddq    ymm1, ymm1, xmm0
    vpaddq    ymm1, ymm1, set1_epi64(1)     # ymm1= 3*n + 1.  Maybe could do this more efficiently?

    vprllq    ymm3, ymm0, 63                # shift bit 1 to the sign bit

    vpsrlq    ymm0, ymm0, 1                 # n /= 2

    # FP blend between integer insns may cost extra bypass latency, but integer blends don't have 1 bit controlling a whole qword.
    vpblendvpd ymm0, ymm0, ymm1, ymm3       # variable blend controlled by the sign bit of each 64-bit element.  I might have the source operands backwards, I always have to look this up.

    # ymm0 = updated n  in each element.

    vpcmpeqq ymm1, ymm0, set1_epi64(1)
    vpandn   ymm4, ymm1, ymm4         # zero out elements of ymm4 where the compare was true

    vpaddq   ymm5, ymm5, ymm4         # count++ in elements where n has never been == 1

    vptest   ymm4, ymm4
    jnz  .inner_loop
    # Fall through when all the n values have reached 1 at some point, and our increment vector is all-zero

    vextracti128 ymm0, ymm5, 1
    vpmaxq .... crap this doesn't exist
    # Actually just delay doing a horizontal max until the very very end.  But you need some way to record max and maxi.

You can and should implement this with intrinsics instead of hand-written asm.


Algorithmic / implementation improvement:

Besides just implementing the same logic with more efficient asm, look for ways to simplify the logic, or avoid redundant work. e.g. memoize to detect common endings to sequences. Or even better, look at 8 trailing bits at once (gnasher's answer)

@EOF points out that tzcnt (or bsf) could be used to do multiple n/=2 iterations in one step. That's probably better than SIMD vectorizing; no SSE or AVX instruction can do that. It's still compatible with doing multiple scalar ns in parallel in different integer registers, though.

So the loop might look like this:

goto loop_entry;  // C++ structured like the asm, for illustration only
do {
   n = n*3 + 1;
  loop_entry:
   shift = _tzcnt_u64(n);
   n >>= shift;
   count += shift;
} while(n != 1);

This may do significantly fewer iterations, but variable-count shifts are slow on Intel SnB-family CPUs without BMI2. 3 uops, 2c latency. (They have an input dependency on the FLAGS because count=0 means the flags are unmodified. They handle this as a data dependency, and take multiple uops because a uop can only have 2 inputs (pre-HSW/BDW anyway)). This is the kind that people complaining about x86's crazy-CISC design are referring to. It makes x86 CPUs slower than they would be if the ISA was designed from scratch today, even in a mostly-similar way. (i.e. this is part of the "x86 tax" that costs speed / power.) SHRX/SHLX/SARX (BMI2) are a big win (1 uop / 1c latency).

It also puts tzcnt (3c on Haswell and later) on the critical path, so it significantly lengthens the total latency of the loop-carried dependency chain. It does remove any need for a CMOV, or for preparing a register holding n>>1, though. @Veedrac's answer overcomes all this by deferring the tzcnt/shift for multiple iterations, which is highly effective (see below).

We can safely use BSF or TZCNT interchangeably, because n can never be zero at that point. TZCNT's machine-code decodes as BSF on CPUs that don't support BMI1. (Meaningless prefixes are ignored, so REP BSF runs as BSF).

TZCNT performs much better than BSF on AMD CPUs that support it, so it can be a good idea to use REP BSF, even if you don't care about setting ZF if the input is zero rather than the output. Some compilers do this when you use __builtin_ctzll even with -mno-bmi.

They perform the same on Intel CPUs, so just save the byte if that's all that matters. TZCNT on Intel (pre-Skylake) still has a false-dependency on the supposedly write-only output operand, just like BSF, to support the undocumented behaviour that BSF with input = 0 leaves its destination unmodified. So you need to work around that unless optimizing only for Skylake, so there's nothing to gain from the extra REP byte. (Intel often goes above and beyond what the x86 ISA manual requires, to avoid breaking widely-used code that depends on something it shouldn't, or that is retroactively disallowed. e.g. Windows 9x's assumes no speculative prefetching of TLB entries, which was safe when the code was written, before Intel updated the TLB management rules.)

Anyway, LZCNT/TZCNT on Haswell have the same false dep as POPCNT: see this Q&A. This is why in gcc's asm output for @Veedrac's code, you see it breaking the dep chain with xor-zeroing on the register it's about to use as TZCNT's destination when it doesn't use dst=src. Since TZCNT/LZCNT/POPCNT never leave their destination undefined or unmodified, this false dependency on the output on Intel CPUs is a performance bug / limitation. Presumably it's worth some transistors / power to have them behave like other uops that go to the same execution unit. The only perf upside is interaction with another uarch limitation: they can micro-fuse a memory operand with an indexed addressing mode on Haswell, but on Skylake where Intel removed the false dep for LZCNT/TZCNT they "un-laminate" indexed addressing modes while POPCNT can still micro-fuse any addr mode.


Improvements to ideas / code from other answers:

@hidefromkgb's answer has a nice observation that you're guaranteed to be able to do one right shift after a 3n+1. You can compute this more even more efficiently than just leaving out the checks between steps. The asm implementation in that answer is broken, though (it depends on OF, which is undefined after SHRD with a count > 1), and slow: ROR rdi,2 is faster than SHRD rdi,rdi,2, and using two CMOV instructions on the critical path is slower than an extra TEST that can run in parallel.

I put tidied / improved C (which guides the compiler to produce better asm), and tested+working faster asm (in comments below the C) up on Godbolt: see the link in @hidefromkgb's answer. (This answer hit the 30k char limit from the large Godbolt URLs, but shortlinks can rot and were too long for goo.gl anyway.)

Also improved the output-printing to convert to a string and make one write() instead of writing one char at a time. This minimizes impact on timing the whole program with perf stat ./collatz (to record performance counters), and I de-obfuscated some of the non-critical asm.


@Veedrac's code

I got a minor speedup from right-shifting as much as we know needs doing, and checking to continue the loop. From 7.5s for limit=1e8 down to 7.275s, on Core2Duo (Merom), with an unroll factor of 16.

code + comments on Godbolt. Don't use this version with clang; it does something silly with the defer-loop. Using a tmp counter k and then adding it to count later changes what clang does, but that slightly hurts gcc.

See discussion in comments: Veedrac's code is excellent on CPUs with BMI1 (i.e. not Celeron/Pentium)

Can I append an array to 'formdata' in javascript?

You can only stringify the array and append it. Sends the array as an actual Array even if it has only one item.

const array = [ 1, 2 ];
let formData = new FormData();
formData.append("numbers", JSON.stringify(array));

How to navigate back to the last cursor position in Visual Studio Code?

As an alternative to the keyboard shortcuts, here's an extension named "Back and Forward buttons" that adds the forward and back buttons to the status bar:

https://marketplace.visualstudio.com/items?itemName=grimmer.vscode-back-forward-button

Laravel 4 with Sentry 2 add user to a group on Registration

Somehow, where you are using Sentry, you're not using its Facade, but the class itself. When you call a class through a Facade you're not really using statics, it's just looks like you are.

Do you have this:

use Cartalyst\Sentry\Sentry; 

In your code?

Ok, but if this line is working for you:

$user = $this->sentry->register(array(     'username' => e($data['username']),     'email' => e($data['email']),      'password' => e($data['password'])     )); 

So you already have it instantiated and you can surely do:

$adminGroup = $this->sentry->findGroupById(5); 

Is there a built-in function to print all the current properties and values of an object?

If you're using this for debugging, and you just want a recursive dump of everything, the accepted answer is unsatisfying because it requires that your classes have good __str__ implementations already. If that's not the case, this works much better:

import json
print(json.dumps(YOUR_OBJECT, 
                 default=lambda obj: vars(obj),
                 indent=1))

MySQL: Curdate() vs Now()

For questions like this, it is always worth taking a look in the manual first. Date and time functions in the mySQL manual

CURDATE() returns the DATE part of the current time. Manual on CURDATE()

NOW() returns the date and time portions as a timestamp in various formats, depending on how it was requested. Manual on NOW().

Ruby max integer

as @Jörg W Mittag pointed out: in jruby, fix num size is always 8 bytes long. This code snippet shows the truth:

fmax = ->{
  if RUBY_PLATFORM == 'java'
    2**63 - 1
  else
    2**(0.size * 8 - 2) - 1
  end
}.call

p fmax.class     # Fixnum

fmax = fmax + 1  

p fmax.class     #Bignum

Cannot create a connection to data source Error (rsErrorOpeningConnection) in SSRS

I had the same issue "Cannot create a connection to data source...Login failed for user.." on Windows 8.1, SQL Server 2014 Developer Edition and Visual Studio 2013 Pro. All solutions offered above by other Stackoverflow Community members did not work for me.

So, I did the next steps (running all Windows applications as Administrator):

  1. VS2013 SSRS: I converted my Data Source to Shared Data Source (.rds) with Windows Authentication (Integrated Security) on the Right Pane "Solution Explorer".

  2. Original (non-shared) Data Source (on the Left Pane "Report Data") got "Don't Use Credentials".

  3. On the Project Properties, I set for "Deployment" "Overwrite DataSources" to "True" and redeployed the Project.

enter image description here

After that, I could run my report without further requirements to enter Credentials. All Shared DataSources were deployed in a separate Directory "DataSources".

enter image description here

enter image description here

Fetch the row which has the Max value for a column

I don't know your exact columns names, but it would be something like this:

    select userid, value
      from users u1
     where date = (select max(date)
                     from users u2
                    where u1.userid = u2.userid)

How to see tomcat is running or not

for localhost,the defaut port is 8080,you can test the link http://localhost:8080 in you browser.if you can see tomcat home page,your tomcat is running

MVC 4 Razor adding input type date

The input date value format needs the date specified as per http://tools.ietf.org/html/rfc3339#section-5.6 full-date.

So I've ended up doing:

<input type="date" id="last-start-date" value="@string.Format("{0:yyyy-MM-dd}", Model.LastStartDate)" />

I did try doing it "properly" using:

[DataType(DataType.Date)]
[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:yyyy-MM-dd}")]
public DateTime LastStartDate
{
    get { return lastStartDate; }
    set { lastStartDate = value; }
}

with

@Html.TextBoxFor(model => model.LastStartDate, 
    new { type = "date" })

Unfortunately that always seemed to set the value attribute of the input to a standard date time so I've ended up applying the formatting directly as above.

Edit:

According to Jorn if you use

@Html.EditorFor(model => model.LastStartDate)

instead of TextBoxFor it all works fine.

C++ Fatal Error LNK1120: 1 unresolved externals

My problem was int Main() instead of int main()

good luck

Android: android.content.res.Resources$NotFoundException: String resource ID #0x5

You are assigning a numeric value to a text field. You have to convert the numeric value to a string with:

String.valueOf(variable)

Using Page_Load and Page_PreRender in ASP.Net

It depends on your requirements.

Page Load : Perform actions common to all requests, such as setting up a database query. At this point, server controls in the tree are created and initialized, the state is restored, and form controls reflect client-side data. See Handling Inherited Events.

Prerender :Perform any updates before the output is rendered. Any changes made to the state of the control in the prerender phase can be saved, while changes made in the rendering phase are lost. See Handling Inherited Events.

Reference: Control Execution Lifecycle MSDN

Try to read about

ASP.NET Page Life Cycle Overview ASP.NET

Control Execution Lifecycle

Regards

Excel VBA Code: Compile Error in x64 Version ('PtrSafe' attribute required)

I think all you need to do for your function is just add PtrSafe: i.e. the first line of your first function should look like this:

Private Declare PtrSafe Function swe_azalt Lib "swedll32.dll" ......

Browser back button handling

You can also add hash when page is loading:

location.hash = "noBack";

Then just handle location hash change to add another hash:

$(window).on('hashchange', function() {
    location.hash = "noBack";
});

That makes hash always present and back button tries to remove hash at first. Hash is then added again by "hashchange" handler - so page would never actually can be changed to previous one.

java.io.FileNotFoundException: /storage/emulated/0/New file.txt: open failed: EACCES (Permission denied)

I suspect you are running Android 6.0 Marshmallow (API 23) or later. If this is the case, you must implement runtime permissions before you try to read/write external storage.

Can a unit test project load the target application's app.config file?

The simplest way to do this is to add the .config file in the deployment section on your unit test.

To do so, open the .testrunconfig file from your Solution Items. In the Deployment section, add the output .config files from your project's build directory (presumably bin\Debug).

Anything listed in the deployment section will be copied into the test project's working folder before the tests are run, so your config-dependent code will run fine.

Edit: I forgot to add, this will not work in all situations, so you may need to include a startup script that renames the output .config to match the unit test's name.

Prevent direct access to a php include file

Actually my advice is to do all of these best practices.

  • Put the documents outside the webroot OR in a directory denied access by the webserver AND
  • Use a define in your visible documents that the hidden documents check for:
      if (!defined(INCL_FILE_FOO)) {
          header('HTTP/1.0 403 Forbidden');
          exit;
      }

This way if the files become misplaced somehow (an errant ftp operation) they are still protected.

How do you add UI inside cells in a google spreadsheet using app script?

Buttons can be added to frozen rows as images. Assigning a function within the attached script to the button makes it possible to run the function. The comment which says you can not is of course a very old comment, possibly things have changed now.

Visual Studio 2015 Update 3 Offline Installer (ISO)

You can check Visual Studio Downloads for available Visual Studio Community, Visual Studio Professional, Visual Studio Enterprise and Visual Studio Code download links.


Update!

There is no direct links of Visual Studio 2015 at Visual Studio Downloads anymore. but the below links still works.


OR simply click on direct links below (for .iso/.exe file):


VSCode area:

How do I set a program to launch at startup

If an application is designed to start when Windows starts (as opposed to when a user logs in), your only option is to involve a Windows Service. Either write the application as a service, or write a simple service that exists only to launch the application.

Writing services can be tricky, and can impose restrictions that may be unacceptable for your particular case. One common design pattern is a front-end/back-end pair, with a service that does the work and an application front-end that communicates with the service to display information to the user.

On the other hand, if you just want your application to start on user login, you can use methods 1 or 2 that Joel Coehoorn listed.

Set transparent background using ImageMagick and commandline prompt

If you want to control the level of transparency you can use rgba. where a is the alpha. 0 for transparent and 1 for opaque. Make sure that final output file must have .png extension for transparency.

convert 
  test.png 
    -channel rgba 
    -matte 
    -fuzz 40% 
    -fill "rgba(255,255,255,0.5)" 
    -opaque "rgb(255,255,255)" 
       semi_transparent.png

How to enable file upload on React's Material UI simple input?

It is work for me ("@material-ui/core": "^4.3.1"):

    <Fragment>
        <input
          color="primary"
          accept="image/*"
          type="file"
          onChange={onChange}
          id="icon-button-file"
          style={{ display: 'none', }}
        />
        <label htmlFor="icon-button-file">
          <Button
            variant="contained"
            component="span"
            className={classes.button}
            size="large"
            color="primary"
          >
            <ImageIcon className={classes.extendedIcon} />
          </Button>
        </label>
      </Fragment>

Reset Excel to default borders

I was having the same trouble with importing from Excel 2010 to Access, appending an "identical" table. Early on in the wizard it said not all my column names were valid, even though I checked them. It turns out that it saw an "empty" column with no column name. When I tried using the import wizard to create a new table instead, it worked. However, I noticed that it had added a blank column to the right of my data and called it "Field30". So I went back to the spreadsheet I was trying to import, selected the columns to the right of the data that I wanted, right-clicked and chose "clear contents." That did the trick and I was able to import the spreadsheet, appending it to my table.

What's the difference between lists and tuples?

Difference between list and tuple

Tuples and lists are both seemingly similar sequence types in Python.

  1. Literal syntax

    We use parenthesis () to construct tuples and square brackets [ ] to get a new list. Also, we can use call of the appropriate type to get required structure — tuple or list.

    someTuple = (4,6)
    someList  = [2,6] 
    
  2. Mutability

    Tuples are immutable, while lists are mutable. This point is the base the for the following ones.

  3. Memory usage

    Due to mutability, you need more memory for lists and less memory for tuples.

  4. Extending

    You can add a new element to both tuples and lists with the only difference that the id of the tuple will be changed (i.e., we’ll have a new object).

  5. Hashing

    Tuples are hashable and lists are not. It means that you can use a tuple as a key in a dictionary. The list can't be used as a key in a dictionary, whereas a tuple can be used

    tup      = (1,2)
    list_    = [1,2] 
    
    c = {tup   : 1}     # ok
    c = {list_ : 1}     # error
    
  6. Semantics

    This point is more about best practice. You should use tuples as heterogeneous data structures, while lists are homogenous sequences.

combining two string variables

IMO, froadie's simple concatenation is fine for a simple case like you presented. If you want to put together several strings, the string join method seems to be preferred:

the_text = ''.join(['the ', 'quick ', 'brown ', 'fox ', 'jumped ', 'over ', 'the ', 'lazy ', 'dog.'])

Edit: Note that join wants an iterable (e.g. a list) as its single argument.

How can I get LINQ to return the object which has the max value for a given property?

Or you can write your own extension method:

static partial class Extensions
{
    public static T WhereMax<T, U>(this IEnumerable<T> items, Func<T, U> selector)
    {
        if (!items.Any())
        {
            throw new InvalidOperationException("Empty input sequence");
        }

        var comparer = Comparer<U>.Default;
        T   maxItem  = items.First();
        U   maxValue = selector(maxItem);

        foreach (T item in items.Skip(1))
        {
            // Get the value of the item and compare it to the current max.
            U value = selector(item);
            if (comparer.Compare(value, maxValue) > 0)
            {
                maxValue = value;
                maxItem  = item;
            }
        }

        return maxItem;
    }
}

Android EditText Max Length

If you want to see a counter label you can use app:counterEnabled and android:maxLength, like:

<android.support.design.widget.TextInputLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  app:counterEnabled="true">

  <EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:maxLength="420" />

</android.support.design.widget.TextInputLayout>

DO NOT set app:counterMaxLength on TextInputLayout because it will conflict with android:maxLength resulting into the issue of invisible chars after the text hits the size limit.

How to send a header using a HTTP request through a curl call?

In case you want send your custom headers, you can do it this way:

curl -v -H @{'custom_header'='custom_header_value'} http://localhost:3000/action?result1=gh&result2=ghk

Simple Android grid example using RecyclerView with GridLayoutManager (like the old GridView)

Short answer

For those who are already familiar with setting up a RecyclerView to make a list, the good news is that making a grid is largely the same. You just use a GridLayoutManager instead of a LinearLayoutManager when you set the RecyclerView up.

recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));

If you need more help than that, then check out the following example.

Full example

The following is a minimal example that will look like the image below.

enter image description here

Start with an empty activity. You will perform the following tasks to add the RecyclerView grid. All you need to do is copy and paste the code in each section. Later you can customize it to fit your needs.

  • Add dependencies to gradle
  • Add the xml layout files for the activity and for the grid cell
  • Make the RecyclerView adapter
  • Initialize the RecyclerView in your activity

Update Gradle dependencies

Make sure the following dependencies are in your app gradle.build file:

compile 'com.android.support:appcompat-v7:27.1.1'
compile 'com.android.support:recyclerview-v7:27.1.1'

You can update the version numbers to whatever is the most current.

Create activity layout

Add the RecyclerView to your xml layout.

activity_main.xml

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

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvNumbers"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

Create grid cell layout

Each cell in our RecyclerView grid is only going to have a single TextView. Create a new layout resource file.

recyclerview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:padding="5dp"
    android:layout_width="50dp"
    android:layout_height="50dp">

        <TextView
            android:id="@+id/info_text"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:background="@color/colorAccent"/>

</LinearLayout>

Create the adapter

The RecyclerView needs an adapter to populate the views in each cell with your data. Create a new java file.

MyRecyclerViewAdapter.java

public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {

    private String[] mData;
    private LayoutInflater mInflater;
    private ItemClickListener mClickListener;

    // data is passed into the constructor
    MyRecyclerViewAdapter(Context context, String[] data) {
        this.mInflater = LayoutInflater.from(context);
        this.mData = data;
    }

    // inflates the cell layout from xml when needed
    @Override
    @NonNull 
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);
        return new ViewHolder(view);
    }

    // binds the data to the TextView in each cell
    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        holder.myTextView.setText(mData[position]);
    }

    // total number of cells
    @Override
    public int getItemCount() {
        return mData.length;
    }


    // stores and recycles views as they are scrolled off screen
    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView myTextView;

        ViewHolder(View itemView) {
            super(itemView);
            myTextView = itemView.findViewById(R.id.info_text);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View view) {
            if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
        }
    }

    // convenience method for getting data at click position
    String getItem(int id) {
        return mData[id];
    }

    // allows clicks events to be caught
    void setClickListener(ItemClickListener itemClickListener) {
        this.mClickListener = itemClickListener;
    }

    // parent activity will implement this method to respond to click events
    public interface ItemClickListener {
        void onItemClick(View view, int position);
    }
}

Notes

  • Although not strictly necessary, I included the functionality for listening for click events on the cells. This was available in the old GridView and is a common need. You can remove this code if you don't need it.

Initialize RecyclerView in Activity

Add the following code to your main activity.

MainActivity.java

public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {

    MyRecyclerViewAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // data to populate the RecyclerView with
        String[] data = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48"};

        // set up the RecyclerView
        RecyclerView recyclerView = findViewById(R.id.rvNumbers);
        int numberOfColumns = 6;
        recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
        adapter = new MyRecyclerViewAdapter(this, data);
        adapter.setClickListener(this);
        recyclerView.setAdapter(adapter);
    }

    @Override
    public void onItemClick(View view, int position) {
        Log.i("TAG", "You clicked number " + adapter.getItem(position) + ", which is at cell position " + position);
    }
}

Notes

  • Notice that the activity implements the ItemClickListener that we defined in our adapter. This allows us to handle cell click events in onItemClick.

Finished

That's it. You should be able to run your project now and get something similar to the image at the top.

Going on

Rounded corners

Auto-fitting columns

Further study

Credit card expiration dates - Inclusive or exclusive?

How do time zones factor in this analysis. Does a card expire in New York before California? Does it depend on the billing or shipping addresses?

Handle spring security authentication exceptions with @ExceptionHandler

The best way I've found is to delegate the exception to the HandlerExceptionResolver

@Component("restAuthenticationEntryPoint")
public class RestAuthenticationEntryPoint implements AuthenticationEntryPoint {

    @Autowired
    private HandlerExceptionResolver resolver;

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException exception) throws IOException, ServletException {
        resolver.resolveException(request, response, null, exception);
    }
}

then you can use @ExceptionHandler to format the response the way you want.

How to restore PostgreSQL dump file into Postgres databases?

1.open the terminal.

2.backup your database with following command

your postgres bin - /opt/PostgreSQL/9.1/bin/

your source database server - 192.168.1.111

your backup file location and name - /home/dinesh/db/mydb.backup

your source db name - mydatabase

/opt/PostgreSQL/9.1/bin/pg_dump --host '192.168.1.111' --port 5432 --username "postgres" --no-password --format custom --blobs --file "/home/dinesh/db/mydb.backup" "mydatabase"

3.restore mydb.backup file into destination.

your destination server - localhost

your destination database name - mydatabase

create database for restore the backup.

/opt/PostgreSQL/9.1/bin/psql -h 'localhost' -p 5432 -U postgres -c "CREATE DATABASE mydatabase"

restore the backup.

/opt/PostgreSQL/9.1/bin/pg_restore --host 'localhost' --port 5432 --username "postgres" --dbname "mydatabase" --no-password --clean "/home/dinesh/db/mydb.backup"

What difference is there between WebClient and HTTPWebRequest classes in .NET?

WebClient is a higher-level abstraction built on top of HttpWebRequest to simplify the most common tasks. For instance, if you want to get the content out of an HttpWebResponse, you have to read from the response stream:

var http = (HttpWebRequest)WebRequest.Create("http://example.com");
var response = http.GetResponse();

var stream = response.GetResponseStream();
var sr = new StreamReader(stream);
var content = sr.ReadToEnd();

With WebClient, you just do DownloadString:

var client = new WebClient();
var content = client.DownloadString("http://example.com");

Note: I left out the using statements from both examples for brevity. You should definitely take care to dispose your web request objects properly.

In general, WebClient is good for quick and dirty simple requests and HttpWebRequest is good for when you need more control over the entire request.

Why is the default value of the string type null instead of an empty string?

Empty strings and nulls are fundamentally different. A null is an absence of a value and an empty string is a value that is empty.

The programming language making assumptions about the "value" of a variable, in this case an empty string, will be as good as initiazing the string with any other value that will not cause a null reference problem.

Also, if you pass the handle to that string variable to other parts of the application, then that code will have no ways of validating whether you have intentionally passed a blank value or you have forgotten to populate the value of that variable.

Another occasion where this would be a problem is when the string is a return value from some function. Since string is a reference type and can technically have a value as null and empty both, therefore the function can also technically return a null or empty (there is nothing to stop it from doing so). Now, since there are 2 notions of the "absence of a value", i.e an empty string and a null, all the code that consumes this function will have to do 2 checks. One for empty and the other for null.

In short, its always good to have only 1 representation for a single state. For a broader discussion on empty and nulls, see the links below.

https://softwareengineering.stackexchange.com/questions/32578/sql-empty-string-vs-null-value

NULL vs Empty when dealing with user input

How to calculate distance from Wifi router using Signal Strength?

In general, this is a really bad way of doing things due to multipath interference. This is definitely more of an RF engineering question than a coding one.

Tl;dr, the wifi RF energy gets scattered in different directions after bouncing off walls, people, the floor etc. There's no way of telling where you are by trianglation alone, unless you're in an empty room with the wifi beacons placed in exactly the right place.

Google is able to get away with this because they essentially can map where every wifi SSID is to a GPS location when any android user (who opts in to their service) walks into range. That way, the next time a user walks by there, even without a perfect GPS signal, the google mothership can tell where you are. Typically, they'll use that in conjunction with a crappy GPS signal.

What I have seen done is a grid of Zigbee or BTLE devices. If you know where these are laid out, you can used the combined RSS to figure out relatively which ones you're closest to, and go from there.

SQL Query Where Date = Today Minus 7 Days

Using dateadd to remove a week from the current date.

datex BETWEEN DATEADD(WEEK,-1,GETDATE()) AND GETDATE()

How can I enable MySQL's slow query log without restarting MySQL?

For slow queries on version < 5.1, the following configuration worked for me:

log_slow_queries=/var/log/mysql/slow-query.log
long_query_time=20
log_queries_not_using_indexes=YES

Also note to place it under [mysqld] part of the config file and restart mysqld.

JavaScript OR (||) variable assignment explanation

It means that if x is set, the value for z will be x, otherwise if y is set then its value will be set as the z's value.

it's the same as

if(x)
  z = x;
else
  z = y;

It's possible because logical operators in JavaScript doesn't return boolean values but the value of the last element needed to complete the operation (in an OR sentence it would be the first non-false value, in an AND sentence it would be the last one). If the operation fails, then false is returned.

CAST DECIMAL to INT

You could try the FLOOR function like this:

SELECT FLOOR(columnName), moreColumns, etc 
FROM myTable 
WHERE ... 

You could also try the FORMAT function, provided you know the decimal places can be omitted:

SELECT FORMAT(columnName,0), moreColumns, etc 
FROM myTable 
WHERE ... 

You could combine the two functions

SELECT FORMAT(FLOOR(columnName),0), moreColumns, etc 
FROM myTable 
WHERE ... 

JavaScript replace \n with <br />

You need the /g for global matching

replace(/\n/g, "<br />");

This works for me for \n - see this answer if you might have \r\n

NOTE: The dupe is the most complete answer for any combination of \r\n, \r or \n

_x000D_
_x000D_
var messagetoSend = document.getElementById('x').value.replace(/\n/g, "<br />");_x000D_
console.log(messagetoSend);
_x000D_
<textarea id="x" rows="9">_x000D_
    Line 1_x000D_
    _x000D_
    _x000D_
    Line 2_x000D_
    _x000D_
    _x000D_
    _x000D_
    _x000D_
    Line 3_x000D_
</textarea>
_x000D_
_x000D_
_x000D_

UPDATE

It seems some visitors of this question have text with the breaklines escaped as

some text\r\nover more than one line"

In that case you need to escape the slashes:

replace(/\\r\\n/g, "<br />");

NOTE: All browsers will ignore \r in a string when rendering.

Writing an Excel file in EPPlus

It's best if you worked with DataSets and/or DataTables. Once you have that, ideally straight from your stored procedure with proper column names for headers, you can use the following method:

ws.Cells.LoadFromDataTable(<DATATABLE HERE>, true, OfficeOpenXml.Table.TableStyles.Light8);

.. which will produce a beautiful excelsheet with a nice table!

Now to serve your file, assuming you have an ExcelPackage object as in your code above called pck..

Response.Clear();

Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition", "attachment;filename=" + sFilename);

Response.BinaryWrite(pck.GetAsByteArray());
Response.End();

How to select rows that have current day's timestamp?

Simply cast it to a date:

SELECT * FROM `table` WHERE CAST(`timestamp` TO DATE) == CAST(NOW() TO DATE)

Dynamically allocating an array of objects

You need an assignment operator so that:

arrayOfAs[i] = A(3);

works as it should.

How can I round down a number in Javascript?

You can try to use this function if you need to round down to a specific number of decimal places

function roundDown(number, decimals) {
    decimals = decimals || 0;
    return ( Math.floor( number * Math.pow(10, decimals) ) / Math.pow(10, decimals) );
}

examples

alert(roundDown(999.999999)); // 999
alert(roundDown(999.999999, 3)); // 999.999
alert(roundDown(999.999999, -1)); // 990

How to toggle font awesome icon on click?

There is another solution you can try by using only the css here is the answer i posted in another post: jQuery Accordion change font awesome icon class on click