Programs & Examples On #Openid4java

What's the difference between compiled and interpreted language?

A compiler, in general, reads higher level language computer code and converts it to either p-code or native machine code. An interpreter runs directly from p-code or an interpreted code such as Basic or Lisp. Typically, compiled code runs much faster, is more compact, and has already found all of the syntax errors and many of the illegal reference errors. Interpreted code only finds such errors after the application attempts to interpret the affected code. Interpreted code is often good for simple applications that will only be used once or at most a couple times, or maybe even for prototyping. Compiled code is better for serious applications. A compiler first takes in the entire program, checks for errors, compiles it and then executes it. Whereas, an interpreter does this line by line, so it takes one line, checks it for errors, and then executes it.

If you need more information, just Google for "difference between compiler and interpreter".

How to run a .awk file?

Put the part from BEGIN....END{} inside a file and name it like my.awk.

And then execute it like below:

awk -f my.awk life.csv >output.txt

Also I see a field separator as ,. You can add that in the begin block of the .awk file as FS=","

Preventing HTML and Script injections in Javascript

You can encode the < and > to their HTML equivelant.

html = html.replace(/</g, "&lt;").replace(/>/g, "&gt;");

How to display HTML tags as plain text

Importing a function from a class in another file?

You can use the below syntax -

from FolderName.FileName import Classname

Python string prints as [u'String']

[u'String'] is a text representation of a list that contains a Unicode string on Python 2.

If you run print(some_list) then it is equivalent to
print'[%s]' % ', '.join(map(repr, some_list)) i.e., to create a text representation of a Python object with the type list, repr() function is called for each item.

Don't confuse a Python object and its text representationβ€”repr('a') != 'a' and even the text representation of the text representation differs: repr(repr('a')) != repr('a').

repr(obj) returns a string that contains a printable representation of an object. Its purpose is to be an unambiguous representation of an object that can be useful for debugging, in a REPL. Often eval(repr(obj)) == obj.

To avoid calling repr(), you could print list items directly (if they are all Unicode strings) e.g.: print ",".join(some_list)β€”it prints a comma separated list of the strings: String

Do not encode a Unicode string to bytes using a hardcoded character encoding, print Unicode directly instead. Otherwise, the code may fail because the encoding can't represent all the characters e.g., if you try to use 'ascii' encoding with non-ascii characters. Or the code silently produces mojibake (corrupted data is passed further in a pipeline) if the environment uses an encoding that is incompatible with the hardcoded encoding.

Spring MVC - How to get all request params in a map in Spring controller?

There is fundamental difference between query parameters and path parameters. It goes like this: www.your_domain?queryparam1=1&queryparam2=2 - query parameters. www.your_domain/path_param1/entity/path_param2 - path parameters.

What I found surprising is that in Spring MVC world a lot of people confuse one for the other. While query parameters are more like criteria for a search, path params will most likely uniquely identify a resource. Having said that, it doesn't mean that you can't have multiple path parameters in your URI, because the resource structure can be nested. For example, let's say you need a specific car resource of a specific person:

www.my_site/customer/15/car/2 - looking for a second car of a 15th customer.

What would be a usecase to put all path parameters into a map? Path parameters don't have a "key" when you look at a URI itself, those keys inside the map would be taken from your @Mapping annotation, for example:

@GetMapping("/booking/{param1}/{param2}")

From HTTP/REST perspective path parameters can't be projected onto a map really. It's all about Spring's flexibility and their desire to accommodate any developers whim, in my opinion.

I would never use a map for path parameters, but it can be quite useful for query parameters.

How to Ping External IP from Java Android

I implemented "ping" in pure Android Java and hosted it on gitlab. It does the same thing as the ping executable, but is much easier to configure. It's has a couple useful features like being able to bind to a given Network.

https://github.com/dburckh/AndroidPing

How do I change TextView Value inside Java Code?

First, add a textView in the XML file

<TextView  
    android:id="@+id/rate_id"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/what_U_want_to_display_in_first_time"
    />

then add a button in xml file with id btn_change_textView and write this two line of code in onCreate() method of activity

Button btn= (Button) findViewById(R.id. btn_change_textView);
TextView textView=(TextView)findViewById(R.id.rate_id);

then use clickListener() on button object like this

btn.setOnClickListener(new View.OnClickListener {
    public void onClick(View v) {
      
        textView.setText("write here what u want to display after button click in string");
    }
});

TypeError: Cannot read property "0" from undefined

Check your array index to see if it's accessed out of bound.

Once I accessed categories[0]. Later I changed the array name from categories to category but forgot to change the access point--from categories[0] to category[0], thus I also get this error.

JavaScript does a poor debug message. In your case, I reckon probably the access gets out of bound.

What's the difference between '$(this)' and 'this'?

Yes you only need $() when you're using jQuery. If you want jQuery's help to do DOM things just keep this in mind.

$(this)[0] === this

Basically every time you get a set of elements back jQuery turns it into a jQuery object. If you know you only have one result, it's going to be in the first element.

$("#myDiv")[0] === document.getElementById("myDiv");

And so on...

How to convert an xml string to a dictionary?

def xml_to_dict(node):
    u''' 
    @param node:lxml_node
    @return: dict 
    '''

    return {'tag': node.tag, 'text': node.text, 'attrib': node.attrib, 'children': {child.tag: xml_to_dict(child) for child in node}}

Google Chrome Printing Page Breaks

I'm having this problem myself - my page breaks work in every browser but Chrome - and was able to isolate it down to the page-break-after element being inside a table cell. (Old, inherited templates in the CMS.)

Apparently Chrome doesn't honor the page-break-before or page-break-after properties inside table cells, so this modified version of Phil's example puts the second and third headline on the same page:

<!DOCTYPE html>

<html>
  <head>
    <meta http-equiv="content-type" content="text/html;charset=UTF-8" />
    <title>Paginated HTML</title>
    <style type="text/css" media="print">
      div.page
      {
        page-break-after: always;
        page-break-inside: avoid;
      }
    </style>
  </head>
  <body>
    <div class="page">
      <h1>This is Page 1</h1>
    </div>

    <table>
    <tr>
        <td>
            <div class="page">
              <h1>This is Page 2</h1>
            </div>
            <div class="page">
              <h1>This is, sadly, still Page 2</h1>
            </div>
        </td>
    </tr>
    </table>
  </body>
</html>

Chrome's implementation is (dubiously) allowed given the CSS specification - you can see more here: http://www.google.com/support/forum/p/Chrome/thread?tid=32f9d9629d6f6789&hl=en

How to define relative paths in Visual Studio Project?

Instead of using relative paths, you could also use the predefined macros of VS to achieve this.

$(ProjectDir) points to the directory of your .vcproj file, $(SolutionDir) is the directory of the .sln file.

You get a list of available macros when opening a project, go to
Properties → Configuration Properties → C/C++ → General
and hit the three dots:

project properties

In the upcoming dialog, hit Macros to see the macros that are predefined by the Studio (consult MSDN for their meaning):

additional include directories

You can use the Macros by typing $(MACRO_NAME) (note the $ and the round brackets).

Explicitly set column value to null SQL Developer

If you want to use the GUI... click/double-click the table and select the Data tab. Click in the column value you want to set to (null). Select the value and delete it. Hit the commit button (green check-mark button). It should now be null.

enter image description here

More info here:

How to use the SQL Worksheet in SQL Developer to Insert, Update and Delete Data

How to create Java gradle project

Here is what it worked for me.. I wanted to create a hello world java application with gradle with the following requirements.

  1. The application has external jar dependencies
  2. Create a runnable fat jar with all dependent classes copied to the jar
  3. Create a runnable jar with all dependent libraries copied to a directory "dependencies" and add the classpath in the manifest.

Here is the solution :

  • Install the latest gradle ( check gradle --version . I used gradle 6.6.1)
  • Create a folder and open a terminal
  • Execute gradle init --type java-application
  • Add the required data in the command line
  • Import the project into an IDE (IntelliJ or Eclipse)
  • Edit the build.gradle file with the following tasks.

Runnable fat Jar

task fatJar(type: Jar) {
 clean
 println("Creating fat jar")
 manifest {
    attributes 'Main-Class': 'com.abc.gradle.hello.App'
 }
 archiveName "${runnableJar}"
 from {
    configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
    configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
 } with jar
 println("Fat jar is created")
}

Copy Dependencies

task copyDepends(type: Copy) {
   from configurations.default
   into "${dependsDir}"
}

Create jar with classpath dependecies in manifest

task createJar(type: Jar) {
   println("Cleaning...")
   clean
   manifest {
    attributes('Main-Class': 'com.abc.gradle.hello.App',
            'Class-Path': configurations.default.collect { 'dependencies/' + 
             it.getName() }.join(' ')
    )
}
  from {
      configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
  } with jar
  println "${outputJar} created"
}

Here is the complete build.gradle

plugins {
    id 'java'
   id 'application'
}
repositories {
    mavenCentral()
}
dependencies {
  implementation 'org.slf4j:slf4j-api:1.7.30'
  implementation 'ch.qos.logback:logback-classic:1.2.3'
  implementation 'ch.qos.logback:logback-core:1.2.3'
  testImplementation 'junit:junit:4.13'
}
def outputJar = "${buildDir}/libs/${rootProject.name}.jar"
def dependsDir = "${buildDir}/libs/dependencies/"
def runnableJar = "${rootProject.name}_fat.jar";

//Create runnable fat jar
task fatJar(type: Jar) {
   clean
   println("Creating fat jar")
   manifest {
    attributes 'Main-Class': 'com.abc.gradle.hello.App'
  }
  archiveName "${runnableJar}"
  from {
    configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
    configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
  } with jar
  println("Fat jar is created")
}

//Copy dependent libraries to directory.
task copyDepends(type: Copy) {
 from configurations.default
 into "${dependsDir}"
}

//Create runnable jar with dependencies
task createJar(type: Jar) {
 println("Cleaning...")
 clean
 manifest {
    attributes('Main-Class': 'com.abc.gradle.hello.App',
            'Class-Path': configurations.default.collect { 'dependencies/' + 
            it.getName() }.join(' ')
    )
 }
 from {
     configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
 } with jar
  println "${outputJar} created"
}

Gradle build commands
Create fat jar : gradle fatJar
Copy dependencies : gradle copyDepends
Create runnable jar with dependencies : gradle createJar

More details can be read here : https://jafarmlp.medium.com/a-simple-java-project-with-gradle-2c323ae0e43d

Understanding the map function

Python3 - map(func, iterable)

One thing that wasn't mentioned completely (although @BlooB kinda mentioned it) is that map returns a map object NOT a list. This is a big difference when it comes to time performance on initialization and iteration. Consider these two tests.

import time
def test1(iterable):
    a = time.clock()
    map(str, iterable)
    a = time.clock() - a

    b = time.clock()
    [ str(x) for x in iterable ]
    b = time.clock() - b

    print(a,b)


def test2(iterable):
    a = time.clock()
    [ x for x in map(str, iterable)]
    a = time.clock() - a

    b = time.clock()
    [ str(x) for x in iterable ]
    b = time.clock() - b

    print(a,b)


test1(range(2000000))  # Prints ~1.7e-5s   ~8s
test2(range(2000000))  # Prints ~9s        ~8s

As you can see initializing the map function takes almost no time at all. However iterating through the map object takes longer than simply iterating through the iterable. This means that the function passed to map() is not applied to each element until the element is reached in the iteration. If you want a list use list comprehension. If you plan to iterate through in a for loop and will break at some point, then use map.

How to pass integer from one Activity to another?

Their are two methods you can use to pass an integer. One is as shown below.

A.class

Intent myIntent = new Intent(A.this, B.class);
myIntent.putExtra("intVariableName", intValue);
startActivity(myIntent);

B.class

Intent intent = getIntent();
int intValue = intent.getIntExtra("intVariableName", 0);

The other method converts the integer to a string and uses the following code.

A.class

Intent intent = new Intent(A.this, B.class);
Bundle extras = new Bundle();
extras.putString("StringVariableName", intValue + "");
intent.putExtras(extras);
startActivity(intent);

The code above will pass your integer value as a string to class B. On class B, get the string value and convert again as an integer as shown below.

B.class

   Bundle extras = getIntent().getExtras();
   String stringVariableName = extras.getString("StringVariableName");
   int intVariableName = Integer.parseInt(stringVariableName);

How do you make a div tag into a link

<div style="cursor:pointer" onclick="document.location='http://www.google.com'">Content Goes Here</div>

get next sequence value from database using hibernate

Here is what worked for me (specific to Oracle, but using scalar seems to be the key)

Long getNext() {
    Query query = 
        session.createSQLQuery("select MYSEQ.nextval as num from dual")
            .addScalar("num", StandardBasicTypes.BIG_INTEGER);

    return ((BigInteger) query.uniqueResult()).longValue();
}

Thanks to the posters here: springsource_forum

Sass .scss: Nesting and multiple classes?

You can use the parent selector reference &, it will be replaced by the parent selector after compilation:

For your example:

.container {
    background:red;
    &.desc{
       background:blue;
    }
}

/* compiles to: */
.container {
    background: red;
}
.container.desc {
    background: blue;
}

The & will completely resolve, so if your parent selector is nested itself, the nesting will be resolved before replacing the &.

This notation is most often used to write pseudo-elements and -classes:

.element{
    &:hover{ ... }
    &:nth-child(1){ ... }
}

However, you can place the & at virtually any position you like*, so the following is possible too:

.container {
    background:red;
    #id &{
       background:blue;
    }
}

/* compiles to: */
.container {
    background: red;
}
#id .container {
    background: blue;
}

However be aware, that this somehow breaks your nesting structure and thus may increase the effort of finding a specific rule in your stylesheet.

*: No other characters than whitespaces are allowed in front of the &. So you cannot do a direct concatenation of selector+& - #id& would throw an error.

PHP cURL error code 60

First you have to download the certificate from this link

https://curl.haxx.se/ca/cacert.pem

and put it in a location you want the name of downloadable file is : cacert.pem So in my case I will put it under C:\wamp64\bin\php\cacert.pem

Then you have to specify the location of the php.ini file

For example, I am using php 7 the php.ini file is located at : C:\wamp64\bin\php\php7.0.10\php.ini

So access to that file and uncommit this line ;openssl.cafile

also update it to be looks like this openssl.cafile="C:\wamp64\bin\php\cacert.pem"

Finally restart your apache server and that's all

When running WebDriver with Chrome browser, getting message, "Only local connections are allowed" even though browser launches properly

This is an informational message only. What the message is telling you is that the chromedriver executable will only accept connections from the local machine.

Most driver implementations (the Chrome driver and the IE driver for sure) create a HTTP server. The language bindings (Java, Python, Ruby, .NET, etc.) all use a JSON-over-HTTP protocol to communicate with the driver and automate the browser. Since the HTTP server is simply listening on an open port for HTTP requests generated by the language bindings, connections to the HTTP server started by the language bindings are only allowed to come from other processes on the same host. Note carefully that this limitation does not apply to connections the browser can make to outside websites; rather it simply prevents incoming connections from other websites.

How do I get the fragment identifier (value after hash #) from a URL?

I had the URL from run time, below gave the correct answer:

let url = "www.site.com/index.php#hello";
alert(url.split('#')[1]);

hope this helps

Read user input inside a loop

You can redirect the regular stdin through unit 3 to keep the get it inside the pipeline:

{ cat notify-finished | while read line; do
    read -u 3 input
    echo "$input"
done; } 3<&0

BTW, if you really are using cat this way, replace it with a redirect and things become even easier:

while read line; do
    read -u 3 input
    echo "$input"
done 3<&0 <notify-finished

Or, you can swap stdin and unit 3 in that version -- read the file with unit 3, and just leave stdin alone:

while read line <&3; do
    # read & use stdin normally inside the loop
    read input
    echo "$input"
done 3<notify-finished

Store select query's output in one array in postgres

There are two ways. One is to aggregate:

SELECT array_agg(column_name::TEXT)
FROM information.schema.columns
WHERE table_name = 'aean'

The other is to use an array constructor:

SELECT ARRAY(
SELECT column_name 
FROM information.schema.columns 
WHERE table_name = 'aean')

I'm presuming this is for plpgsql. In that case you can assign it like this:

colnames := ARRAY(
SELECT column_name
FROM information.schema.columns
WHERE table_name='aean'
);

Common HTTPclient and proxy

If your software uses a ProxySelector (for example for using a PAC-script instead of a static host/port) and your HTTPComponents is version 4.3 or above then you can use your ProxySelector for your HttpClient like this:

ProxySelector myProxySelector = ...;
HttpClient myHttpClient = HttpClientBuilder.create().setRoutePlanner(new SystemDefaultRoutePlanner(myProxySelector))).build();

And then do your requests as usual:

HttpGet myRequest = new HttpGet("/");
myHttpClient.execute(myRequest);

ImageButton in Android

You don't have to use it using src attribute

Wrong way (The image won't fit the button)

android:src="@drawable/myimage"

Right way is to use background atttribute

<ImageButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:background="@drawable/skin" />

where skin is an xml

skin.xml

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

    <!-- <item android:drawable="@drawable/button_disabled" android:state_enabled="false"/> -->
    <item android:drawable="@drawable/button_pressed" android:state_pressed="true"/>
    <!-- <item android:drawable="@drawable/button_focused" android:state_focused="true"/> -->
    <item android:drawable="@drawable/button_normal"/>

</selector>

using button_pressed.png and button_normal.png

This will also help you in creating your skinned button with 4 states of pressed , normal , disabled and focussed. Make sure to keep same sizes of all pngs

Difference between a user and a schema in Oracle?

For most of the people who are more familiar with MariaDB or MySQL this seems little confusing because in MariaDB or MySQL they have different schemas (which includes different tables, view , PLSQL blocks and DB objects etc) and USERS are the accounts which can access those schema. Therefore no specific user can belong to any particular schema. The permission has be to given to that Schema then the user can access it. The Users and Schema is separated in databases like MySQL and MariaDB.

In Oracle schema and users are almost treated as same. To work with that schema you need to have the permission which is where you will feel that the schema name is nothing but user name. Permissions can be given across schemas to access different database objects from different schema. In oracle we can say that a user owns a schema because when you create a user you create DB objects for it and vice a versa.

How to split the filename from a full path in batch?

I don't know that much about batch files but couldn't you have a pre-made batch file copied from the home directory to the path you have that would return a list of the names of the files then use that name?

Here is a link I think might be helpful in making the pre-made batch file.

http://www.ericphelps.com/batch/lists/filelist.htm

How to Delete a directory from Hadoop cluster which is having comma(,) in its name?

In hadoop1.0:

hadoop fs -rmr /PATH/ON/HDFS

In hadoop2.0:

hdfs dfs -rm -R /PATH/ON/HDFS

Use \ to escape , in path

Java compiler level does not match the version of the installed Java project facet

In Eclipse, right click on your project, go to Maven> Update projetc. Wait and the error will disappear. This is already configured correctly the version of Java for this project.

enter image description here

Eventviewer eventid for lock and unlock

The event IDs to look for in pre-Vista Windows are 528, 538, and 680. 528 usually stands for successful unlock of workstation.

The codes for newer Windows versions differ, see below answers for more infos.

How to put the legend out of the plot

It's worth refreshing this question, as newer versions of Matplotlib have made it much easier to position the legend outside the plot. I produced this example with Matplotlib version 3.1.1.

Users can pass a 2-tuple of coordinates to the loc parameter to position the legend anywhere in the bounding box. The only gotcha is you need to run plt.tight_layout() to get matplotlib to recompute the plot dimensions so the legend is visible:

import matplotlib.pyplot as plt

plt.plot([0, 1], [0, 1], label="Label 1")
plt.plot([0, 1], [0, 2], label='Label 2')

plt.legend(loc=(1.05, 0.5))
plt.tight_layout()

This leads to the following plot:

plot with legend outside

References:

Recursive file search using PowerShell

Here is the method that I finally came up with after struggling:

Get-ChildItem -Recurse -Path path/with/wildc*rds/ -Include file.*

To make the output cleaner (only path), use:

(Get-ChildItem -Recurse -Path path/with/wildc*rds/ -Include file.*).fullname

To get only the first result, use:

(Get-ChildItem -Recurse -Path path/with/wildc*rds/ -Include file.*).fullname | Select -First 1

Now for the important stuff:

To search only for files/directories do not use -File or -Directory (see below why). Instead use this for files:

Get-ChildItem -Recurse -Path ./path*/ -Include name* | where {$_.PSIsContainer -eq $false}

and remove the -eq $false for directories. Do not leave a trailing wildcard like bin/*.

Why not use the built in switches? They are terrible and remove features randomly. For example, in order to use -Include with a file, you must end the path with a wildcard. However, this disables the -Recurse switch without telling you:

Get-ChildItem -File -Recurse -Path ./bin/* -Include *.lib

You'd think that would give you all *.libs in all subdirectories, but it only will search top level of bin.

In order to search for directories, you can use -Directory, but then you must remove the trailing wildcard. For whatever reason, this will not deactivate -Recurse. It is for these reasons that I recommend not using the builtin flags.

You can shorten this command considerably:

Get-ChildItem -Recurse -Path ./path*/ -Include name* | where {$_.PSIsContainer -eq $false}

becomes

gci './path*/' -s -Include 'name*' | where {$_.PSIsContainer -eq $false}
  • Get-ChildItem is aliased to gci
  • -Path is default to position 0, so you can just make first argument path
  • -Recurse is aliased to -s
  • -Include does not have a shorthand
  • Use single quotes for spaces in names/paths, so that you can surround the whole command with double quotes and use it in Command Prompt. Doing it the other way around (surround with single quotes) causes errors

How do I remove the space between inline/inline-block elements?

So a lot of complicated answers. The easiest way I can think of is to just give one of the elements a negative margin (either margin-left or margin-right depending on the position of the element).

How to find an object in an ArrayList by property

For finding objects which are meaningfully equal, you need to override equals and hashcode methods for the class. You can find a good tutorial here.

http://www.thejavageek.com/2013/06/28/significance-of-equals-and-hashcode/

How to set -source 1.7 in Android Studio and Gradle

Right click on your project > Open Module Setting > Select "Project" in "Project Setting" section

Change the Project SDK to latest(may be API 21) and Project language level to 7+

How to randomly select rows in SQL?

SELECT * FROM TABLENAME ORDER BY random() LIMIT 5; 

How to link a folder with an existing Heroku app

heroku login 

git init

heroku git:remote -a app-name123

then check the remote repo :

git remote -v

Java8: sum values from specific field of the objects in a list

You can try

int sum = list.stream().filter(o->o.field>10).mapToInt(o->o.field).sum();

Like explained here

Dump Mongo Collection into JSON format

From the Mongo documentation:

The mongoexport utility takes a collection and exports to either JSON or CSV. You can specify a filter for the query, or a list of fields to output

Read more here: http://www.mongodb.org/display/DOCS/mongoexport

Change DataGrid cell colour based on values

        // Example: Adding a converter to a column (C#)
        Style styleReading = new Style(typeof(TextBlock));
        Setter s = new Setter();
        s.Property = TextBlock.ForegroundProperty;
        Binding b = new Binding();
        b.RelativeSource = RelativeSource.Self;
        b.Path = new PropertyPath(TextBlock.TextProperty);
        b.Converter = new ReadingForegroundSetter();
        s.Value = b;
        styleReading.Setters.Add(s);
        col.ElementStyle = styleReading;

How do I set the rounded corner radius of a color drawable using xml?

Use the <shape> tag to create a drawable in XML with rounded corners. (You can do other stuff with the shape tag like define a color gradient as well).

Here's a copy of a XML file I'm using in one of my apps to create a drawable with a white background, black border and rounded corners:

<?xml version="1.0" encoding="UTF-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android"> 
    <solid android:color="#ffffffff"/>    
             
    <stroke android:width="3dp"
            android:color="#ff000000" />

    <padding android:left="1dp"
             android:top="1dp"
             android:right="1dp"
             android:bottom="1dp" /> 
             
    <corners android:radius="7dp" /> 
</shape>

How to make child divs always fit inside parent div?

For closure, I think the answer to this question is that there is no solution. The only way to get the behavior I want is with javascript.

How to extract a single value from JSON response?

using json.loads will turn your data into a python dictionary.

Dictionaries values are accessed using ['key']

resp_str = {
  "name" : "ns1:timeSeriesResponseType",
  "declaredType" : "org.cuahsi.waterml.TimeSeriesResponseType",
  "scope" : "javax.xml.bind.JAXBElement$GlobalScope",
  "value" : {
    "queryInfo" : {
      "creationTime" : 1349724919000,
      "queryURL" : "http://waterservices.usgs.gov/nwis/iv/",
      "criteria" : {
        "locationParam" : "[ALL:103232434]",
        "variableParam" : "[00060, 00065]"
      },
      "note" : [ {
        "value" : "[ALL:103232434]",
        "title" : "filter:sites"
      }, {
        "value" : "[mode=LATEST, modifiedSince=null]",
        "title" : "filter:timeRange"
      }, {
        "value" : "sdas01",
        "title" : "server"
      } ]
    }
  },
  "nil" : false,
  "globalScope" : true,
  "typeSubstituted" : false
}

would translate into a python diction

resp_dict = json.loads(resp_str)

resp_dict['name'] # "ns1:timeSeriesResponseType"

resp_dict['value']['queryInfo']['creationTime'] # 1349724919000

C++ How do I convert a std::chrono::time_point to long and back

I would also note there are two ways to get the number of ms in the time point. I'm not sure which one is better, I've benchmarked them and they both have the same performance, so I guess it's a matter of preference. Perhaps Howard could chime in:

auto now = system_clock::now();

//Cast the time point to ms, then get its duration, then get the duration's count.
auto ms = time_point_cast<milliseconds>(now).time_since_epoch().count();

//Get the time point's duration, then cast to ms, then get its count.
auto ms = duration_cast<milliseconds>(tpBid.time_since_epoch()).count();

The first one reads more clearly in my mind going from left to right.

vertical-align: middle doesn't work

You should set a fixed value to your span's line-height property:

.float, .twoline {
    line-height: 100px;
}

What is the ideal data type to use when storing latitude / longitude in a MySQL database?

MySQL's Spatial Extensions are the best option because you have the full list of spatial operators and indices at your disposal. A spatial index will allow you to perform distance-based calculations very quickly. Please keep in mind that as of 6.0, the Spatial Extension is still incomplete. I am not putting down MySQL Spatial, only letting you know of the pitfalls before you get too far along on this.

If you are dealing strictly with points and only the DISTANCE function, this is fine. If you need to do any calculations with Polygons, Lines, or Buffered-Points, the spatial operators do not provide exact results unless you use the "relate" operator. See the warning at the top of 21.5.6. Relationships such as contains, within, or intersects are using the MBR, not the exact geometry shape (i.e. an Ellipse is treated like a Rectangle).

Also, the distances in MySQL Spatial are in the same units as your first geometry. This means if you're using Decimal Degrees, then your distance measurements are in Decimal Degrees. This will make it very difficult to get exact results as you get furthur from the equator.

Placing Unicode character in CSS content value

Why don't you just save/serve the CSS file as UTF-8?

nav a:hover:after {
    content: "?";
}

If that's not good enough, and you want to keep it all-ASCII:

nav a:hover:after {
    content: "\2193";
}

The general format for a Unicode character inside a string is \000000 to \FFFFFF – a backslash followed by six hexadecimal digits. You can leave out leading 0 digits when the Unicode character is the last character in the string or when you add a space after the Unicode character. See the spec below for full details.


Relevant part of the CSS2 spec:

Third, backslash escapes allow authors to refer to characters they cannot easily put in a document. In this case, the backslash is followed by at most six hexadecimal digits (0..9A..F), which stand for the ISO 10646 ([ISO10646]) character with that number, which must not be zero. (It is undefined in CSS 2.1 what happens if a style sheet does contain a character with Unicode codepoint zero.) If a character in the range [0-9a-fA-F] follows the hexadecimal number, the end of the number needs to be made clear. There are two ways to do that:

  1. with a space (or other white space character): "\26 B" ("&B"). In this case, user agents should treat a "CR/LF" pair (U+000D/U+000A) as a single white space character.
  2. by providing exactly 6 hexadecimal digits: "\000026B" ("&B")

In fact, these two methods may be combined. Only one white space character is ignored after a hexadecimal escape. Note that this means that a "real" space after the escape sequence must be doubled.

If the number is outside the range allowed by Unicode (e.g., "\110000" is above the maximum 10FFFF allowed in current Unicode), the UA may replace the escape with the "replacement character" (U+FFFD). If the character is to be displayed, the UA should show a visible symbol, such as a "missing character" glyph (cf. 15.2, point 5).

  • Note: Backslash escapes are always considered to be part of an identifier or a string (i.e., "\7B" is not punctuation, even though "{" is, and "\32" is allowed at the start of a class name, even though "2" is not).
    The identifier "te\st" is exactly the same identifier as "test".

Comprehensive list: Unicode Character 'DOWNWARDS ARROW' (U+2193).

How to pass an ArrayList to a varargs method parameter?

A shorter version of the accepted answer using Guava:

.getMap(Iterables.toArray(locations, WorldLocation.class));

can be shortened further by statically importing toArray:

import static com.google.common.collect.toArray;
// ...

    .getMap(toArray(locations, WorldLocation.class));

TypeError: module.__init__() takes at most 2 arguments (3 given)

In my case where I had the problem I was referring to a module when I tried extending the class.

import logging
class UserdefinedLogging(logging):

If you look at the Documentation Info, you'll see "logging" displayed as module.

In this specific case I had to simply inherit the logging module to create an extra class for the logging.

How to check if a socket is connected/disconnected in C#?

As zendar wrote, it is nice to use the Socket.Poll and Socket.Available, but you need to take into consideration that the socket might not have been initialized in the first place. This is the last (I believe) piece of information and it is supplied by the Socket.Connected property. The revised version of the method would looks something like this:

 static bool IsSocketConnected(Socket s)
    {
        return !((s.Poll(1000, SelectMode.SelectRead) && (s.Available == 0)) || !s.Connected);

/* The long, but simpler-to-understand version:

        bool part1 = s.Poll(1000, SelectMode.SelectRead);
        bool part2 = (s.Available == 0);
        if ((part1 && part2 ) || !s.Connected)
            return false;
        else
            return true;

*/
    }

Bootstrap change div order with pull-right, pull-left on 3 columns

Try this...

<div class="row">
    <div class="col-xs-3">
        Menu
    </div>
    <div class="col-xs-9">
        <div class="row">
          <div class="col-sm-4 col-sm-push-8">
          Right content
          </div>
          <div class="col-sm-8 col-sm-pull-4">
          Content
          </div>
       </div>
    </div>
</div>

Bootply

How can I plot a confusion matrix?

@bninopaul 's answer is not completely for beginners

here is the code you can "copy and run"

import seaborn as sn
import pandas as pd
import matplotlib.pyplot as plt

array = [[13,1,1,0,2,0],
         [3,9,6,0,1,0],
         [0,0,16,2,0,0],
         [0,0,0,13,0,0],
         [0,0,0,0,15,0],
         [0,0,1,0,0,15]]

df_cm = pd.DataFrame(array, range(6), range(6))
# plt.figure(figsize=(10,7))
sn.set(font_scale=1.4) # for label size
sn.heatmap(df_cm, annot=True, annot_kws={"size": 16}) # font size

plt.show()

result

Is a Java hashmap search really O(1)?

It depends on the algorithm you choose to avoid collisions. If your implementation uses separate chaining then the worst case scenario happens where every data element is hashed to the same value (poor choice of the hash function for example). In that case, data lookup is no different from a linear search on a linked list i.e. O(n). However, the probability of that happening is negligible and lookups best and average cases remain constant i.e. O(1).

Unable to access JSON property with "-" dash

jsonObj.profile-id is a subtraction expression (i.e. jsonObj.profile - id).

To access a key that contains characters that cannot appear in an identifier, use brackets:

jsonObj["profile-id"]

Parse XLSX with Node and create json

I think this code will do what you want. It stores the first row as a set of headers, then stores the rest in a data object which you can write to disk as JSON.

var XLSX = require('xlsx');
var workbook = XLSX.readFile('test.xlsx');
var sheet_name_list = workbook.SheetNames;
sheet_name_list.forEach(function(y) {
    var worksheet = workbook.Sheets[y];
    var headers = {};
    var data = [];
    for(z in worksheet) {
        if(z[0] === '!') continue;
        //parse out the column, row, and value
        var col = z.substring(0,1);
        var row = parseInt(z.substring(1));
        var value = worksheet[z].v;

        //store header names
        if(row == 1) {
            headers[col] = value;
            continue;
        }

        if(!data[row]) data[row]={};
        data[row][headers[col]] = value;
    }
    //drop those first two rows which are empty
    data.shift();
    data.shift();
    console.log(data);
});

prints out

[ { id: 1,
    headline: 'team: sally pearson',
    location: 'Australia',
    'body text': 'majority have…',
    media: 'http://www.youtube.com/foo' },
  { id: 2,
    headline: 'Team: rebecca',
    location: 'Brazil',
    'body text': 'it is a long established…',
    media: 'http://s2.image.foo/' } ]

Table 'performance_schema.session_variables' doesn't exist

The mysql_upgrade worked for me as well:

# mysql_upgrade -u root -p --force
# systemctl restart mysqld

Regards, MSz.

SQL conditional SELECT

You want the CASE statement:

SELECT
  CASE 
    WHEN @SelectField1 = 1 THEN Field1
    WHEN @SelectField2 = 1 THEN Field2
    ELSE NULL
  END AS NewField
FROM Table

EDIT: My example is for combining the two fields into one field, depending on the parameters supplied. It is a one-or-neither solution (not both). If you want the possibility of having both fields in the output, use Quassnoi's solution.

JIRA JQL searching by date - is there a way of getting Today() (Date) instead of Now() (DateTime)

We're using Jira 6.2 and I use this query:

updatedDate > startOfDay(-1d) AND updatedDate < endOfDay(-1)

to return all of the issues that were updated from the previous day. You can combine with whichever queries you want to return the appropriate issues for the previous day.

Removing leading and trailing spaces from a string

No boost, no regex, just the string library. It's that simple.

string trim(const string s) { // removes whitespace characters from beginnig and end of string s
    const int l = (int)s.length();
    int a=0, b=l-1;
    char c;
    while(a<l && ((c=s.at(a))==' '||c=='\t'||c=='\n'||c=='\v'||c=='\f'||c=='\r'||c=='\0')) a++;
    while(b>a && ((c=s.at(b))==' '||c=='\t'||c=='\n'||c=='\v'||c=='\f'||c=='\r'||c=='\0')) b--;
    return s.substr(a, 1+b-a);
}

how to print json data in console.log

{"success":true,"input_data":{"quantity-row_122":"1","price-row_122":" 35.1 "}}

console.dir() will do what you need. It will give you a hierarchical structure of the data.

success:function(data){
     console.dir(data);
}

like so

> Object
  > input_data: Object
      price-row_122: " 35.1 "
      quantity-row_122: "1"
    success: true

I don't think you need console.log(JSON.stringify(data)).

To get the data you can do this without stringify:

console.log(data.success); // true
console.log(data.input_data['quantity-row_122']) // "1"
console.log(data.input_data['price-row_122']) // " 35.1 "

Note

The value from input_data Object will be typeof "1": String, but you can convert to number(Int or Float) using ParseInt or ParseFloat, like so:

 typeof parseFloat(data.input_data['price-row_122'], 10) // "number"
 parseFloat(data.input_data['price-row_122'], 10) // 35.1

How to prevent ENTER keypress to submit a web form?

This link provides a solution that has worked for me in Chrome, FF, and IE9 plus the emulator for IE7 and 8 that comes with IE9's developer tool (F12).

http://webcheatsheet.com/javascript/disable_enter_key.php

How to validate GUID is a GUID

if(MyGuid!=Guild.Empty)

{

//Valid Guild

}

else {

// Invalid Guild

}

How do I set up cron to run a file just once at a specific time?

For those who is not able to access/install at in environment, can use custom script:

#!/bin/bash
if [ $# -lt 2 ]; then
echo ""
echo "Syntax Error!"
echo "Usage: $0 <shell script> <datetime>"
echo "<datetime> format: %Y%m%d%H%M"
echo "Example: $0 /home/user/scripts/server_backup.sh 202008142350"
echo ""
exit 1
fi

while true; do
  t=$(date +%Y%m%d%H%M);      
  if [ $t -eq $2 ]; then
    /bin/bash $1
    echo DONE $(date);
    break;
  fi;
  sleep 1;
done

Let's name the script as run1time.sh Example could be something like:

nohup bash run1time.sh /path/to/your/script.sh 202008150300 &

Chrome says my extension's manifest file is missing or unreadable

I also encountered this issue.

My problem was that I renamed the folder my extension was in, so all I had to do was delete and reload the extension.

Thought this might help some people out there.

How to git-cherry-pick only changes to certain files?

Merge a branch into new one (squash) and remove the files not needed:

git checkout master
git checkout -b <branch>
git merge --squash <source-branch-with-many-commits>
git reset HEAD <not-needed-file-1>
git checkout -- <not-needed-file-1>
git reset HEAD <not-needed-file-2>
git checkout -- <not-needed-file-2>
git commit

How to set a value for a selectize.js input?

Answer by the user 'onlyblank' is correct. A small addition to that- You can set more than 1 default values if you want.

Instead of passing on id to the setValue(), pass an array. Example:

var $select = $("#my_input").selectize();
var selectize = $select[0].selectize;
var yourDefaultIds = [1,2]; # find the ids using search as shown by the user onlyblank
selectize.setValue(defaultValueIds);

How do I remove leading whitespace in Python?

The function strip will remove whitespace from the beginning and end of a string.

my_str = "   text "
my_str = my_str.strip()

will set my_str to "text".

How to hide a button programmatically?

public void OnClick(View.v)
Button b1 = (Button) findViewById(R.id.playButton);
b1.setVisiblity(View.INVISIBLE);

How to include Javascript file in Asp.Net page

I assume that you are using MasterPage so within your master page you should have

<head runat="server">
    <asp:ContentPlaceHolder ID="head" runat="server">
    </asp:ContentPlaceHolder>
</head>

And within any of your pages based on that MasterPage add this

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
    <script src="js/yourscript.js" type="text/javascript"></script>
</asp:Content>

Maven compile with multiple src directories

This worked for with maven 3.5.4 and now Intellij Idea see this code as source:

<plugin>
     <groupId>org.apache.maven.plugins</groupId>
     <artifactId>maven-compiler-plugin</artifactId>
     <version>3.3</version>
     <configuration>
         <generatedSourcesDirectory>src/main/generated</generatedSourcesDirectory>                    
     </configuration>
</plugin>

How to use LINQ Distinct() with multiple fields

Employee emp1 = new Employee() { ID = 1, Name = "Narendra1", Salary = 11111, Experience = 3, Age = 30 };Employee emp2 = new Employee() { ID = 2, Name = "Narendra2", Salary = 21111, Experience = 10, Age = 38 };
Employee emp3 = new Employee() { ID = 3, Name = "Narendra3", Salary = 31111, Experience = 4, Age = 33 };
Employee emp4 = new Employee() { ID = 3, Name = "Narendra4", Salary = 41111, Experience = 7, Age = 33 };

List<Employee> lstEmployee = new List<Employee>();

lstEmployee.Add(emp1);
lstEmployee.Add(emp2);
lstEmployee.Add(emp3);
lstEmployee.Add(emp4);

var eemmppss=lstEmployee.Select(cc=>new {cc.ID,cc.Age}).Distinct();

Split a List into smaller lists of N size

I had encountered this same need, and I used a combination of Linq's Skip() and Take() methods. I multiply the number I take by the number of iterations this far, and that gives me the number of items to skip, then I take the next group.

        var categories = Properties.Settings.Default.MovementStatsCategories;
        var items = summariesWithinYear
            .Select(s =>  s.sku).Distinct().ToList();

        //need to run by chunks of 10,000
        var count = items.Count;
        var counter = 0;
        var numToTake = 10000;

        while (count > 0)
        {
            var itemsChunk = items.Skip(numToTake * counter).Take(numToTake).ToList();
            counter += 1;

            MovementHistoryUtilities.RecordMovementHistoryStatsBulk(itemsChunk, categories, nLogger);

            count -= numToTake;
        }

How is Docker different from a virtual machine?

There are a lot of nice technical answers here that clearly discuss the differences between VMs and containers as well as the origins of Docker.

For me the fundamental difference between VMs and Docker is how you manage the promotion of your application.

With VMs you promote your application and its dependencies from one VM to the next DEV to UAT to PRD.

  1. Often these VM's will have different patches and libraries.
  2. It is not uncommon for multiple applications to share a VM. This requires managing configuration and dependencies for all the applications.
  3. Backout requires undoing changes in the VM. Or restoring it if possible.

With Docker the idea is that you bundle up your application inside its own container along with the libraries it needs and then promote the whole container as a single unit.

  1. Except for the kernel the patches and libraries are identical.
  2. As a general rule there is only one application per container which simplifies configuration.
  3. Backout consists of stopping and deleting the container.

So at the most fundamental level with VMs you promote the application and its dependencies as discrete components whereas with Docker you promote everything in one hit.

And yes there are issues with containers including managing them although tools like Kubernetes or Docker Swarm greatly simplify the task.

Efficient way to determine number of digits in an integer

I was working on a program that required me to check if the user correctly answered how many digits were in a number, so i had to develop a way to check the amount of digits in an integer. It ended up being a relatively easy thing to solve.

double check=0, exponent=1000;

while(check<=1)
{
    check=number/pow(10, exponent);
    exponent--;
}

exponent=exponent+2;
cout<<exponent<<endl;

This ended up being my answer which currently works with numbers with less than 10^1000 digits (can be changed by changing the value of exponent).

P.S. I know this answer is ten years late but I got here on 2020 so other people might use it.

How to compare two tables column by column in oracle

Using the minus operator was working but also it was taking more time to execute which was not acceptable. I have a similar kind of requirement for data migration and I used the NOT IN operator for that. The modified query is :

select * 
from A 
where (emp_id,emp_name) not in 
   (select emp_id,emp_name from B) 
   union all 
select * from B 
where (emp_id,emp_name) not in 
   (select emp_id,emp_name from A); 

This query executed fast. Also you can add any number of columns in the select query. Only catch is that both tables should have the exact same table structure for this to be executed.

Are (non-void) self-closing tags valid in HTML5?

As Nikita Skvortsov pointed out, a self-closing div will not validate. This is because a div is a normal element, not a void element.

According to the HTML5 spec, tags that cannot have any contents (known as void elements) can be self-closing*. This includes the following tags:

area, base, br, col, embed, hr, img, input, 
keygen, link, meta, param, source, track, wbr

The "/" is completely optional on the above tags, however, so <img/> is not different from <img>, but <img></img> is invalid.

*Note: foreign elements can also be self-closing, but I don't think that's in scope for this answer.

How to pass object with NSNotificationCenter

Swift 2 Version

As @Johan Karlsson pointed out... I was doing it wrong. Here's the proper way to send and receive information with NSNotificationCenter.

First, we look at the initializer for postNotificationName:

init(name name: String,
   object object: AnyObject?,
 userInfo userInfo: [NSObject : AnyObject]?)

source

We'll be passing our information using the userInfo param. The [NSObject : AnyObject] type is a hold-over from Objective-C. So, in Swift land, all we need to do is pass in a Swift dictionary that has keys that are derived from NSObject and values which can be AnyObject.

With that knowledge we create a dictionary which we'll pass into the object parameter:

 var userInfo = [String:String]()
 userInfo["UserName"] = "Dan"
 userInfo["Something"] = "Could be any object including a custom Type."

Then we pass the dictionary into our object parameter.

Sender

NSNotificationCenter.defaultCenter()
    .postNotificationName("myCustomId", object: nil, userInfo: userInfo)

Receiver Class

First we need to make sure our class is observing for the notification

override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("btnClicked:"), name: "myCustomId", object: nil)   
}
    

Then we can receive our dictionary:

func btnClicked(notification: NSNotification) {
   let userInfo : [String:String!] = notification.userInfo as! [String:String!]
   let name = userInfo["UserName"]
   print(name)
}

Understanding MongoDB BSON Document size limit

Nested Depth for BSON Documents: MongoDB supports no more than 100 levels of nesting for BSON documents.

More more info vist

How can I find the length of a number?

You have to make the number to string in order to take length

var num = 123;

alert((num + "").length);

or

alert(num.toString().length);

What is the best way to implement nested dictionaries?

defaultdict() is your friend!

For a two dimensional dictionary you can do:

d = defaultdict(defaultdict)
d[1][2] = 3

For more dimensions you can:

d = defaultdict(lambda :defaultdict(defaultdict))
d[1][2][3] = 4

Concatenate two char* strings in a C program

When you use string literals, such as "this is a string" and in your case "sssss" and "kkkk", the compiler puts them in read-only memory. However, strcat attempts to write the second argument after the first. You can solve this problem by making a sufficiently sized destination buffer and write to that.

char destination[10]; // 5 times s, 4 times k, one zero-terminator
char* str1;
char* str2;
str1 = "sssss";
str2 = "kkkk";
strcpy(destination, str1);
printf("%s",strcat(destination,str2));

Note that in recent compilers, you usually get a warning for casting string literals to non-const character pointers.

Display image at 50% of its "native" size

Set the image to be the background of a div, then set the background size to be half the width of the image.

<div class="myimage"></div>

Then in your css, if your image is 300px x 200px:

.myimage {
    background: url('images/myimage.png') no-repeat;
    background-size:150px;
    width:150px;
    height:100px;
}

SVN repository backup strategies

Basically it's safe to copy the repository folder if the svn server is stopped. (source: https://groups.google.com/forum/?fromgroups#!topic/visualsvn/i_55khUBrys%5B1-25%5D )

So if you're allowed to stop the server, do it and just copy the repository, either with some script or a backup tool. Cobian Backup fits here nicely as it can stop and start services automatically, and it can do incremental backups so you're only backing up parts of repository that have changed recently (useful if the repository is large and you're backing up to remote location).

Example:

  1. Install Cobian Backup
  2. Add a backup task:

    • Set source to repository folder (e.g. C:\Repositories\),

    • Add pre-backup event "STOP_SERVICE" VisualSVN,

    • Add post-backup event, "START_SERVICE" VisualSVN,

    • Set other options as needed. We've set up incremental backups including removal of old ones, backup schedule, destination, compression incl. archive splitting etc.

  3. Profit!

Binding an Image in WPF MVVM

@Sheridan thx.. if I try your example with "DisplayedImagePath" on both sides, it works with absolute path as you show.

As for the relative paths, this is how I always connect relative paths, I first include the subdirectory (!) and the image file in my project.. then I use ~ character to denote the bin-path..

    public string DisplayedImagePath
    {
        get { return @"~\..\images\osc.png"; }
    }

This was tested, see below my Solution Explorer in VS2015..

example of image binding in VS2015)

Note: if you want a Click event, use the Button tag around the image,

_x000D_
_x000D_
<Button Click="image_Click" Width="128" Height="128"  Grid.Row="2" VerticalAlignment="Top" HorizontalAlignment="Left">_x000D_
  <Image x:Name="image" Source="{Binding DisplayedImagePath}" Margin="0,0,0,0" />_x000D_
</Button>
_x000D_
_x000D_
_x000D_

What's the difference between .NET Core, .NET Framework, and Xamarin?

.NET 5 will be a unified version of all .NET variants coming in November 2020, so there will be no need to choose between variants anymore. enter image description here

How can I mock an ES6 module import using Jest?

To mock an ES6 dependency module default export using Jest:

import myModule from '../myModule';
import dependency from '../dependency';

jest.mock('../dependency');

// If necessary, you can place a mock implementation like this:
dependency.mockImplementation(() => 42);

describe('myModule', () => {
  it('calls the dependency once with double the input', () => {
    myModule(2);

    expect(dependency).toHaveBeenCalledTimes(1);
    expect(dependency).toHaveBeenCalledWith(4);
  });
});

The other options didn't work for my case.

What is the difference between user variables and system variables?

Environment variable (can access anywhere/ dynamic object) is a type of variable. They are of 2 types system environment variables and user environment variables.

System variables having a predefined type and structure. That are used for system function. Values that produced by the system are stored in the system variable. They generally indicated by using capital letters Example: HOME,PATH,USER

User environment variables are the variables that determined by the user,and are represented by using small letters.

No provider for Http StaticInjectorError

I was trying to fix the issue for about an hour and just deiced to restart the server. Only to see the issue is fixed.

If you make changes to APP module and the issue remains the same, stop the server and try running the serve command again.

Using ionic 4 with angular 7

Div Height in Percentage

There is the semicolon missing (;) after the "50%"

but you should also notice that the percentage of your div is connected to the div that contains it.

for instance:

<div id="wrapper">
  <div class="container">
   adsf
  </div>
</div>

#wrapper {
  height:100px;
}
.container
{
  width:80%;
  height:50%;
  background-color:#eee;
}

here the height of your .container will be 50px. it will be 50% of the 100px from the wrapper div.

if you have:

adsf

#wrapper {
  height:400px;
}
.container
{
  width:80%;
  height:50%;
  background-color:#eee;
}

then you .container will be 200px. 50% of the wrapper.

So you may want to look at the divs "wrapping" your ".container"...

Best approach to real time http streaming to HTML5 video client

Take a look at JSMPEG project. There is a great idea implemented there β€” to decode MPEG in the browser using JavaScript. Bytes from encoder (FFMPEG, for example) can be transfered to browser using WebSockets or Flash, for example. If community will catch up, I think, it will be the best HTML5 live video streaming solution for now.

How to pass a value from Vue data to href?

Or you can do that with ES6 template literal:

<a :href="`/job/${r.id}`"

How do you configure HttpOnly cookies in tomcat / java webapps?

Update: The JSESSIONID stuff here is only for older containers. Please use jt's currently accepted answer unless you are using < Tomcat 6.0.19 or < Tomcat 5.5.28 or another container that does not support HttpOnly JSESSIONID cookies as a config option.

When setting cookies in your app, use

response.setHeader( "Set-Cookie", "name=value; HttpOnly");

However, in many webapps, the most important cookie is the session identifier, which is automatically set by the container as the JSESSIONID cookie.

If you only use this cookie, you can write a ServletFilter to re-set the cookies on the way out, forcing JSESSIONID to HttpOnly. The page at http://keepitlocked.net/archive/2007/11/05/java-and-httponly.aspx http://alexsmolen.com/blog/?p=16 suggests adding the following in a filter.

if (response.containsHeader( "SET-COOKIE" )) {
  String sessionid = request.getSession().getId();
  response.setHeader( "SET-COOKIE", "JSESSIONID=" + sessionid 
                      + ";Path=/<whatever>; Secure; HttpOnly" );
} 

but note that this will overwrite all cookies and only set what you state here in this filter.

If you use additional cookies to the JSESSIONID cookie, then you'll need to extend this code to set all the cookies in the filter. This is not a great solution in the case of multiple-cookies, but is a perhaps an acceptable quick-fix for the JSESSIONID-only setup.

Please note that as your code evolves over time, there's a nasty hidden bug waiting for you when you forget about this filter and try and set another cookie somewhere else in your code. Of course, it won't get set.

This really is a hack though. If you do use Tomcat and can compile it, then take a look at Shabaz's excellent suggestion to patch HttpOnly support into Tomcat.

removing table border

To remove from all tables, (add this to the head or external style sheet)

<style type="text/css">
table td{
border:none;
}
</style>

The image shows where the style is coming from (Firebug)

Assigning the output of a command to a variable

You can use a $ sign like:

OUTPUT=$(expression)

How to switch databases in psql?

In PostgreSQL, you can use the \connect meta-command of the client tool psql:

\connect DBNAME

or in short:

\c DBNAME

How to find out which processes are using swap space in Linux?

It's not entirely clear if you mean you want to find the process who has most pages swapped out or process who caused most pages to be swapped out.

For the first you may run top and order by swap (press 'Op'), for the latter you can run vmstat and look for non-zero entries for 'so'.

What are the different NameID format used for?

About this I think you can reference to http://docs.oasis-open.org/security/saml/Post2.0/sstc-saml-tech-overview-2.0.html.

Here're my understandings about this, with the Identity Federation Use Case to give a details for those concepts:

  • Persistent identifiers-

IdP provides the Persistent identifiers, they are used for linking to the local accounts in SPs, but they identify as the user profile for the specific service each alone. For example, the persistent identifiers are kind of like : johnForAir, jonhForCar, johnForHotel, they all just for one specified service, since it need to link to its local identity in the service.

  • Transient identifiers-

Transient identifiers are what IdP tell the SP that the users in the session have been granted to access the resource on SP, but the identities of users do not offer to SP actually. For example, The assertion just like β€œAnonymity(Idp doesn’t tell SP who he is) has the permission to access /resource on SP”. SP got it and let browser to access it, but still don’t know Anonymity' real name.

  • unspecified identifiers-

The explanation for it in the spec is "The interpretation of the content of the element is left to individual implementations". Which means IdP defines the real format for it, and it assumes that SP knows how to parse the format data respond from IdP. For example, IdP gives a format data "UserName=XXXXX Country=US", SP get the assertion, and can parse it and extract the UserName is "XXXXX".

How to break out of nested loops?

If you need the values of i and j, this should work but with less performance than others

for(i;i< 1000; i++){    
    for(j; j< 1000; j++){
        if(condition)
            break;
    }
    if(condition) //the same condition
        break;
}

Use IntelliJ to generate class diagram

Use Diagrams | Show Diagram... from the context menu of a package. Invoking it on the project root will show module dependencies diagram.

If you need multiple packages, you can drag & drop them to the already opened diagram for the first package and press e to expand it.

Note: This feature is available in the Ultimate Edition, not the free Community Edition.

Execution order of events when pressing PrimeFaces p:commandButton

It failed because you used ajax="false". This fires a full synchronous request which in turn causes a full page reload, causing the oncomplete to be never fired (note that all other ajax-related attributes like process, onstart, onsuccess, onerror and update are also never fired).

That it worked when you removed actionListener is also impossible. It should have failed the same way. Perhaps you also removed ajax="false" along it without actually understanding what you were doing. Removing ajax="false" should indeed achieve the desired requirement.


Also is it possible to execute actionlistener and oncomplete simultaneously?

No. The script can only be fired before or after the action listener. You can use onclick to fire the script at the moment of the click. You can use onstart to fire the script at the moment the ajax request is about to be sent. But they will never exactly simultaneously be fired. The sequence is as follows:

  • User clicks button in client
  • onclick JavaScript code is executed
  • JavaScript prepares ajax request based on process and current HTML DOM tree
  • onstart JavaScript code is executed
  • JavaScript sends ajax request from client to server
  • JSF retrieves ajax request
  • JSF processes the request lifecycle on JSF component tree based on process
  • actionListener JSF backing bean method is executed
  • action JSF backing bean method is executed
  • JSF prepares ajax response based on update and current JSF component tree
  • JSF sends ajax response from server to client
  • JavaScript retrieves ajax response
    • if HTTP response status is 200, onsuccess JavaScript code is executed
    • else if HTTP response status is 500, onerror JavaScript code is executed
  • JavaScript performs update based on ajax response and current HTML DOM tree
  • oncomplete JavaScript code is executed

Note that the update is performed after actionListener, so if you were using onclick or onstart to show the dialog, then it may still show old content instead of updated content, which is poor for user experience. You'd then better use oncomplete instead to show the dialog. Also note that you'd better use action instead of actionListener when you intend to execute a business action.

See also:

jQuery get value of selected radio button

First, you cannot have multiple elements with the same id. I know you said you can't control how the form is created, but...try to somehow remove all the ids from the radios, or make them unique.

To get the value of the selected radio button, select it by name with the :checked filter.

var selectedVal = "";
var selected = $("input[type='radio'][name='s_2_1_6_0']:checked");
if (selected.length > 0) {
    selectedVal = selected.val();
}

EDIT

So you have no control over the names. In that case I'd say put these radio buttons all inside a div, named, say, radioDiv, then slightly modify your selector:

var selectedVal = "";
var selected = $("#radioDiv input[type='radio']:checked");
if (selected.length > 0) {
    selectedVal = selected.val();
}

How do I obtain a list of all schemas in a Sql Server database

You can also query the INFORMATION_SCHEMA.SCHEMATA view:

SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA

I believe querying the INFORMATION_SCHEMA views is recommended as they protect you from changes to the underlying sys tables. From the SQL Server 2008 R2 Help:

Information schema views provide an internal, system table-independent view of the SQL Server metadata. Information schema views enable applications to work correctly although significant changes have been made to the underlying system tables. The information schema views included in SQL Server comply with the ISO standard definition for the INFORMATION_SCHEMA.

Ironically, this is immediately preceded by this note:

Some changes have been made to the information schema views that break backward compatibility. These changes are described in the topics for the specific views.

Using Switch Statement to Handle Button Clicks

Hi its quite simple to make switch between buttons using switch case:-

 package com.example.browsebutton;


    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.Toast;

        public class MainActivity extends Activity implements OnClickListener {
        Button b1,b2;
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
                b1=(Button)findViewById(R.id.button1);

                b2=(Button)findViewById(R.id.button2);
                b1.setOnClickListener(this);
                b2.setOnClickListener(this);
            }



            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                 int id=v.getId();
                 switch(id) {
                    case R.id.button1:
                  Toast.makeText(getBaseContext(), "btn1", Toast.LENGTH_LONG).show();
                //Your Operation

                  break;

                    case R.id.button2:
                          Toast.makeText(getBaseContext(), "btn2", Toast.LENGTH_LONG).show();


                          //Your Operation
                          break;
            }

        }}

IF EXISTS, THEN SELECT ELSE INSERT AND THEN SELECT

You need to do this in transaction to ensure two simultaneous clients won't insert same fieldValue twice:

SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
BEGIN TRANSACTION
    DECLARE @id AS INT
    SELECT @id = tableId FROM table WHERE fieldValue=@newValue
    IF @id IS NULL
    BEGIN
       INSERT INTO table (fieldValue) VALUES (@newValue)
       SELECT @id = SCOPE_IDENTITY()
    END
    SELECT @id
COMMIT TRANSACTION

you can also use Double-checked locking to reduce locking overhead

DECLARE @id AS INT
SELECT @id = tableID FROM table (NOLOCK) WHERE fieldValue=@newValue
IF @id IS NULL
BEGIN
    SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
    BEGIN TRANSACTION
        SELECT @id = tableID FROM table WHERE fieldValue=@newValue
        IF @id IS NULL
        BEGIN
           INSERT INTO table (fieldValue) VALUES (@newValue)
           SELECT @id = SCOPE_IDENTITY()
        END
    COMMIT TRANSACTION
END
SELECT @id

As for why ISOLATION LEVEL SERIALIZABLE is necessary, when you are inside a serializable transaction, the first SELECT that hits the table creates a range lock covering the place where the record should be, so nobody else can insert the same record until this transaction ends.

Without ISOLATION LEVEL SERIALIZABLE, the default isolation level (READ COMMITTED) would not lock the table at read time, so between SELECT and UPDATE, somebody would still be able to insert. Transactions with READ COMMITTED isolation level do not cause SELECT to lock. Transactions with REPEATABLE READS lock the record (if found) but not the gap.

Using getline() in C++

int main(){
.... example with file
     //input is a file
    if(input.is_open()){
        cin.ignore(1,'\n'); //it ignores everything after new line
        cin.getline(buffer,255); // save it in buffer
        input<<buffer; //save it in input(it's a file)
        input.close();
    }
}

dotnet ef not found in .NET Core 3

For everyone using .NET Core CLI on MinGW MSYS. After installing using

dotnet tool install --global dotnet-ef

add this line to to bashrc file c:\msys64\home\username\ .bashrc (location depend on your setup)

export PATH=$PATH:/c/Users/username/.dotnet/tools

Git commit -a "untracked files"?

git commit -am "msg" is not same as git add file and git commit -m "msg"

If you have some files which were never added to git tracking you still need to do git add file

The β€œgit commit -a” command is a shortcut to a two-step process. After you modify a file that is already known by the repo, you still have to tell the repo, β€œHey! I want to add this to the staged files and eventually commit it to you.” That is done by issuing the β€œgit add” command. β€œgit commit -a” is staging the file and committing it in one step.

Source: "git commit -a" and "git add"

How to get value of Radio Buttons?

You can do easily like bellow,

_employee.Gender = rbtnMale.Checked?rbtnMale.Text:_employee.Gender;
_employee.Gender = rbtnFemale.Checked?rbtnFemale.Text:_employee.Gender;

How to create many labels and textboxes dynamically depending on the value of an integer variable?

Here is a simple example that should let you keep going add somethink that would act as a placeholder to your winform can be TableLayoutPanel

and then just add controls to it

   for ( int i = 0; i < COUNT; i++ ) {


    Label lblTitle = new Label();
    lblTitle.Text = i+"Your Text";
    youlayOut.Controls.Add( lblTitle, 0, i );

    TextBox txtValue = new TextBox();
    youlayOut.Controls.Add( txtValue, 2, i );
}

Convert time.Time to string

strconv.Itoa(int(time.Now().Unix()))

jQuery scroll to ID from different page

On the link put a hash:

<a href="otherpage.html#elementID">Jump</a>

And on other page, you can do:

$('html,body').animate({
  scrollTop: $(window.location.hash).offset().top
});

On other page, you should have element with id set to elementID to scroll to. Of course you can change the name of it.

Spring JSON request getting 406 (not Acceptable)

Check <mvc:annotation-driven /> in dispatcherservlet.xml , if not add it. And add

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-core-asl</artifactId>
    <version>1.9.13</version>
</dependency>

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.9.13</version>
</dependency>

these dependencies in your pom.xml

How to change language of app when user selects language?

You should either remove android:configChanges="locale" from manifest, which will cause activity to reload, or override onConfigurationChanged method:

@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
    // your code here, you can use newConfig.locale if you need to check the language
    // or just re-set all the labels to desired string resource
}

NullPointerException in Java with no StackTrace

You are probably using the HotSpot JVM (originally by Sun Microsystems, later bought by Oracle, part of the OpenJDK), which performs a lot of optimization. To get the stack traces back, you need to pass the option -XX:-OmitStackTraceInFastThrow to the JVM.

The optimization is that when an exception (typically a NullPointerException) occurs for the first time, the full stack trace is printed and the JVM remembers the stack trace (or maybe just the location of the code). When that exception occurs often enough, the stack trace is not printed anymore, both to achieve better performance and not to flood the log with identical stack traces.

To see how this is implemented in the HotSpot JVM, grab a copy of it and search for the global variable OmitStackTraceInFastThrow. Last time I looked at the code (in 2019), it was in the file graphKit.cpp.

D3 transform scale and translate

I realize this question is fairly old, but wanted to share a quick demo of group transforms, paths/shapes, and relative positioning, for anyone else who found their way here looking for more info:

http://bl.ocks.org/dustinlarimer/6050773

What is the default scope of a method in Java?

The default scope is "default". It's weird--see these references for more info.

conflicting types for 'outchar'

In C, the order that you define things often matters. Either move the definition of outchar to the top, or provide a prototype at the top, like this:

#include <stdio.h> #include <stdlib.h>  void outchar(char ch);  int main() {     outchar('A');     outchar('B');     outchar('C');     return 0; }  void outchar(char ch) {     printf("%c", ch); } 

Also, you should be specifying the return type of every function. I added that for you.

Set Focus on EditText

    mEditText.setFocusableInTouchMode(true);
    mEditText.requestFocus();

    if(mEditText.requestFocus()) {
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
    }

how to set mongod --dbpath

Create a directory db in home, inside db another directory data

cd 
mkdir db
cd db
mkdir data

then type this command--

mongod --dbpath ~/db/data

What to use now Google News API is deprecated?

Looks like you might have until the end of 2013 before they officially close it down. http://groups.google.com/group/google-ajax-search-api/browse_thread/thread/6aaa1b3529620610/d70f8eec3684e431?lnk=gst&q=news+api#d70f8eec3684e431

Also, it sounds like they are building a replacement... but it's going to cost you.

I'd say, go to a different service. I think bing has a news API.

You might enjoy (or not) reading: http://news.ycombinator.com/item?id=1864625

Time comparison

import java.util.Calendar;

Calendar cal = Calendar.getInstance();
int currentHour = cal.get(Calendar.HOUR);
if (currentHour > 10 && currentHour < 18) {
    //then rock on
}

Can I call a constructor from another constructor (do constructor chaining) in C++?

Simply put, you cannot before C++11.

C++11 introduces delegating constructors:

Delegating constructor

If the name of the class itself appears as class-or-identifier in the member initializer list, then the list must consist of that one member initializer only; such constructor is known as the delegating constructor, and the constructor selected by the only member of the initializer list is the target constructor

In this case, the target constructor is selected by overload resolution and executed first, then the control returns to the delegating constructor and its body is executed.

Delegating constructors cannot be recursive.

class Foo {
public: 
  Foo(char x, int y) {}
  Foo(int y) : Foo('a', y) {} // Foo(int) delegates to Foo(char,int)
};

Note that a delegating constructor is an all-or-nothing proposal; if a constructor delegates to another constructor, the calling constructor isn't allowed to have any other members in its initialization list. This makes sense if you think about initializing const/reference members once, and only once.

if condition in sql server update query

Since you're using SQL 2008:

UPDATE
    table_Name

SET
    column_A  
     = CASE
        WHEN @flag = '1' THEN @new_value
        ELSE 0
    END + column_A,

    column_B  
     = CASE
        WHEN @flag = '0' THEN @new_value
        ELSE 0
    END + column_B 
WHERE
    ID = @ID

If you were using SQL 2012:

UPDATE
    table_Name
SET
    column_A  = column_A + IIF(@flag = '1', @new_value, 0),
    column_B  = column_B + IIF(@flag = '0', @new_value, 0)
WHERE
    ID = @ID

flutter corner radius with transparent background

If both containers are siblings and the bottom container has rounded corners and the top container is dynamic then you will have to use the stack widget

Stack(
 children: [
   /*your_widget_1*/,
  /*your_widget_2*/,
 ],
);

Appending an id to a list if not already present in a string

What you are trying to do can almost certainly be achieved with a set.

>>> x = set([1,2,3])
>>> x.add(2)
>>> x
set([1, 2, 3])
>>> x.add(4)
>>> x.add(4)
>>> x
set([1, 2, 3, 4])
>>> 

using a set's add method you can build your unique set of ids very quickly. Or if you already have a list

unique_ids = set(id_list)

as for getting your inputs in numeric form you can do something like

>>> ids = [int(n) for n in '350882 348521 350166\r\n'.split()]
>>> ids
[350882, 348521, 350166]

Maven build failed: "Unable to locate the Javac Compiler in: jre or jdk issue"

Setting fork to true resolved the issue for me.

<configuration>
    <fork>true</fork>
    <source>1.6</source>
    <target>1.6</target>
</configuration>

Use dynamic variable names in `dplyr`

I am also adding an answer that augments this a little bit because I came to this entry when searching for an answer, and this had almost what I needed, but I needed a bit more, which I got via @MrFlik 's answer and the R lazyeval vignettes.

I wanted to make a function that could take a dataframe and a vector of column names (as strings) that I want to be converted from a string to a Date object. I couldn't figure out how to make as.Date() take an argument that is a string and convert it to a column, so I did it as shown below.

Below is how I did this via SE mutate (mutate_()) and the .dots argument. Criticisms that make this better are welcome.

library(dplyr)

dat <- data.frame(a="leave alone",
                  dt="2015-08-03 00:00:00",
                  dt2="2015-01-20 00:00:00")

# This function takes a dataframe and list of column names
# that have strings that need to be
# converted to dates in the data frame
convertSelectDates <- function(df, dtnames=character(0)) {
    for (col in dtnames) {
        varval <- sprintf("as.Date(%s)", col)
        df <- df %>% mutate_(.dots= setNames(list(varval), col))
    }
    return(df)
}

dat <- convertSelectDates(dat, c("dt", "dt2"))
dat %>% str

Send FormData and String Data Together Through JQuery AJAX?

I try to contribute my code collaboration with my friend . modification from this forum.

$('#upload').on('click', function() {
            var fd = new FormData();
              var c=0;
              var file_data,arr;
              $('input[type="file"]').each(function(){
                  file_data = $('input[type="file"]')[c].files; // get multiple files from input file
                  console.log(file_data);
               for(var i = 0;i<file_data.length;i++){
                   fd.append('arr[]', file_data[i]); // we can put more than 1 image file
               }
              c++;
           }); 

               $.ajax({
                   url: 'test.php',
                   data: fd,
                   contentType: false,
                   processData: false,
                   type: 'POST',
                   success: function(data){
                       console.log(data);
                   }
               });
           });

this my html file

<form name="form" id="form" method="post" enctype="multipart/form-data">
<input type="file" name="file[]"multiple>
<input type="button" name="submit" value="upload" id="upload">

this php code file

<?php 
$count = count($_FILES['arr']['name']); // arr from fd.append('arr[]')
var_dump($count);
echo $count;
var_dump($_FILES['arr']);

if ( $count == 0 ) {
   echo 'Error: ' . $_FILES['arr']['error'][0] . '<br>';
}
else {
    $i = 0;
    for ($i = 0; $i < $count; $i++) { 
        move_uploaded_file($_FILES['arr']['tmp_name'][$i], 'uploads/' . $_FILES['arr']['name'][$i]);
    }

}
?>

I hope people with same problem , can fast solve this problem. i got headache because multiple upload image.

How to use Apple's new .p8 certificate for APNs in firebase console

When you upload your p8 file in Firebase, in the box that reads App ID Prefix(required) , you should enter your team ID. You can get it from https://developer.apple.com/account/#/membership and copy/paste the Team ID as shown below.

enter image description here

Adding a regression line on a ggplot

In general, to provide your own formula you should use arguments x and y that will correspond to values you provided in ggplot() - in this case x will be interpreted as x.plot and y as y.plot. You can find more information about smoothing methods and formula via the help page of function stat_smooth() as it is the default stat used by geom_smooth().

ggplot(data,aes(x.plot, y.plot)) +
  stat_summary(fun.data=mean_cl_normal) + 
  geom_smooth(method='lm', formula= y~x)

If you are using the same x and y values that you supplied in the ggplot() call and need to plot the linear regression line then you don't need to use the formula inside geom_smooth(), just supply the method="lm".

ggplot(data,aes(x.plot, y.plot)) +
  stat_summary(fun.data= mean_cl_normal) + 
  geom_smooth(method='lm')

Spark - Error "A master URL must be set in your configuration" when submitting an app

How does spark context in your application pick the value for spark master?

  • You either provide it explcitly withing SparkConf while creating SC.
  • Or it picks from the System.getProperties (where SparkSubmit earlier put it after reading your --master argument).

Now, SparkSubmit runs on the driver -- which in your case is the machine from where you're executing the spark-submit script. And this is probably working as expected for you too.

However, from the information you've posted it looks like you are creating a spark context in the code that is sent to the executor -- and given that there is no spark.master system property available there, it fails. (And you shouldn't really be doing so, if this is the case.)

Can you please post the GroupEvolutionES code (specifically where you're creating SparkContext(s)).

MySQL combine two columns and add into a new column

Are you sure you want to do this? In essence, you're duplicating the data that is in the three original columns. From that point on, you'll need to make sure that the data in the combined field matches the data in the first three columns. This is more overhead for your application, and other processes that update the system will need to understand the relationship.

If you need the data, why not select in when you need it? The SQL for selecting what would be in that field would be:

SELECT CONCAT(zipcode, ' - ', city, ', ', state) FROM Table;

This way, if the data in the fields changes, you don't have to update your combined field.

How to get name of the computer in VBA?

A shell method to read the environmental variable for this courtesy of devhut

Debug.Print CreateObject("WScript.Shell").ExpandEnvironmentStrings("%COMPUTERNAME%")

Same source gives an API method:

Option Explicit

#If VBA7 And Win64 Then
    'x64 Declarations
    Declare PtrSafe Function GetComputerName Lib "kernel32" Alias "GetComputerNameA" (ByVal lpBuffer As String, nSize As Long) As Long
#Else
    'x32 Declaration
    Declare Function GetComputerName Lib "kernel32" Alias "GetComputerNameA" (ByVal lpBuffer As String, nSize As Long) As Long
#End If

Public Sub test()

    Debug.Print ComputerName
    
End Sub

Public Function ComputerName() As String
    Dim sBuff                 As String * 255
    Dim lBuffLen              As Long
    Dim lResult               As Long
 
    lBuffLen = 255
    lResult = GetComputerName(sBuff, lBuffLen)
    If lBuffLen > 0 Then
        ComputerName = Left(sBuff, lBuffLen)
    End If
End Function

Why does npm install say I have unmet dependencies?

I was trying to work on an automated deployment system that runs npm install, so a lot of these solutions wouldn't work for me in an automated fasion. I wasn't in a position to go deleting/re-creating node_modules/ nor could I easily change Node.js versions.

So I ended up running npm shrinkwrap - adding the npm-shrinkwrap.json file to my deployment bundle, and running installs from there. That fixed the problem for me; with the shrinkwrap file as a 'helper', npm seemed to be able to find the right packages and get them installed for me. (Shrinkwrap has other features as well, but this was what I needed it for in this particular case).

Conditional operator in Python?

simple is the best and works in every version.

if a>10: 
    value="b"
else: 
    value="c"

Combine several images horizontally with Python

I would try this:

import numpy as np
import PIL
from PIL import Image

list_im = ['Test1.jpg', 'Test2.jpg', 'Test3.jpg']
imgs    = [ PIL.Image.open(i) for i in list_im ]
# pick the image which is the smallest, and resize the others to match it (can be arbitrary image shape here)
min_shape = sorted( [(np.sum(i.size), i.size ) for i in imgs])[0][1]
imgs_comb = np.hstack( (np.asarray( i.resize(min_shape) ) for i in imgs ) )

# save that beautiful picture
imgs_comb = PIL.Image.fromarray( imgs_comb)
imgs_comb.save( 'Trifecta.jpg' )    

# for a vertical stacking it is simple: use vstack
imgs_comb = np.vstack( (np.asarray( i.resize(min_shape) ) for i in imgs ) )
imgs_comb = PIL.Image.fromarray( imgs_comb)
imgs_comb.save( 'Trifecta_vertical.jpg' )

It should work as long as all images are of the same variety (all RGB, all RGBA, or all grayscale). It shouldn't be difficult to ensure this is the case with a few more lines of code. Here are my example images, and the result:

Test1.jpg

Test1.jpg

Test2.jpg

Test2.jpg

Test3.jpg

Test3.jpg

Trifecta.jpg:

combined images

Trifecta_vertical.jpg

enter image description here

How to check if a json key exists?

You can use the JsonNode#hasNonNull(String fieldName), it mix the has method and the verification if it is a null value or not

Export HTML table to pdf using jspdf

You can also use the jsPDF-AutoTable plugin. You can check out a demo here that uses the following code.

var doc = new jsPDF('p', 'pt');
var elem = document.getElementById("basic-table");
var res = doc.autoTableHtmlToJson(elem);
doc.autoTable(res.columns, res.data);
doc.save("table.pdf");

Android on-screen keyboard auto popping up

Add this in parent layout of the XML.

android:focusable="true" 
android:focusableInTouchMode="true"

It ensures the focus isn't on the editText when the Activity starts.

How to cast/convert pointer to reference in C++

foo(*ob);

You don't need to cast it because it's the same Object type, you just need to dereference it.

How to convert array to a string using methods other than JSON?

There are different ways to do this some of them has given. implode(), join(), var_export(), print_r(), serialize(), json_encode()exc... You can also write your own function without these:

A For() loop is very useful. You can add your array's value to another variable like this:

<?php
    $dizi=array('mother','father','child'); //This is array

    $sayi=count($dizi);
    for ($i=0; $i<$sayi; $i++) {
        $dizin.=("'$dizi[$i]',"); //Now it is string...
    }
         echo substr($dizin,0,-1); //Write it like string :D
?>

In this code we added $dizi's values and comma to $dizin:

$dizin.=("'$dizi[$i]',");

Now

$dizin = 'mother', 'father', 'child',

It's a string, but it has an extra comma :)

And then we deleted the last comma, substr($dizin, 0, -1);

Output:

'mother','father','child'

python ValueError: invalid literal for float()

I had a similar issue reading the serial output from a digital scale. I was reading [3:12] out of a 18 characters long output string.

In my case sometimes there is a null character "\x00" (NUL) which magically appears in the scale's reply string and is not printed.

I was getting the error:

> '     0.00'
> 3 0 fast loop, delta =  10.0 weight =  0.0 
> '     0.00'
> 1 800 fast loop, delta = 10.0 weight =  0.0 
> '     0.00'
> 6 0 fast loop, delta =  10.0 weight =  0.0
> '     0\x00.0' 
> Traceback (most recent call last):
>   File "measure_weight_speed.py", line 172, in start
>     valueScale = float(answer_string) 
>     ValueError: invalid literal for float(): 0

After some research I wrote few lines of code that work in my case.

replyScale = scale_port.read(18)
answer = replyScale[3:12]
answer_decode = answer.replace("\x00", "")
answer_strip = str(answer_decode.strip())
print(repr(answer_strip))
valueScale = float(answer_strip)

The answers in these posts helped:

  1. How to get rid of \x00 in my array of bytes?
  2. Invalid literal for float(): 0.000001, how to fix error?

What is the difference between "long", "long long", "long int", and "long long int" in C++?

Historically, in early C times, when processors had 8 or 16 bit wordlength,intwas identical to todays short(16 bit). In a certain sense, int is a more abstract data type thanchar,short,longorlong long, as you cannot be sure about the bitwidth.

When definingint n;you could translate this with "give me the best compromise of bitwidth and speed on this machine for n". Maybe in the future you should expect compilers to translateintto be 64 bit. So when you want your variable to have 32 bits and not more, better use an explicitlongas data type.

[Edit: #include <stdint.h> seems to be the proper way to ensure bitwidths using the int##_t types, though it's not yet part of the standard.]

How do I parse a string into a number with Dart?

In Dart 2 int.tryParse is available.

It returns null for invalid inputs instead of throwing. You can use it like this:

int val = int.tryParse(text) ?? defaultValue;

Convert UIImage to NSData and convert back to UIImage in Swift?

UIImage(data:imageData,scale:1.0) presuming the image's scale is 1.

In swift 4.2, use below code for get Data().

image.pngData()

Difference between two dates in Python

Use - to get the difference between two datetime objects and take the days member.

from datetime import datetime

def days_between(d1, d2):
    d1 = datetime.strptime(d1, "%Y-%m-%d")
    d2 = datetime.strptime(d2, "%Y-%m-%d")
    return abs((d2 - d1).days)

How do I make a transparent border with CSS?

Many of you must be landing here to find a solution for opaque border instead of a transparent one. In that case you can use rgba, where a stands for alpha.

.your_class {
    height: 100px;
    width: 100px;
    margin: 100px;
    border: 10px solid rgba(255,255,255,.5);
}

Demo

Here, you can change the opacity of the border from 0-1


If you simply want a complete transparent border, the best thing to use is transparent, like border: 1px solid transparent;

How to perform a LEFT JOIN in SQL Server between two SELECT statements?

Try this:

SELECT user.userID, edge.TailUser, edge.Weight 
FROM user
LEFT JOIN edge ON edge.HeadUser = User.UserID
WHERE edge.HeadUser=5043

OR

AND edge.HeadUser=5043

instead of WHERE clausule.

Google Geocoding API - REQUEST_DENIED

Remove the API key parameter and its value.

eg. https://maps.googleapis.com/maps/api/geocode/json?address=[YOUR ADDRESS]&sensor=true

How to fix "containing working copy admin area is missing" in SVN?

fwiw, I had a similar situation and used svn --force delete __dir__. That solved the issue for me. Then i continued working with my working copy as normal.

Parsing JSON in Excel VBA

To parse JSON in VBA without adding a huge library to your workbook project, I created the following solution. It's extremely fast and stores all of the keys and values in a dictionary for easy access:

Function ParseJSON(json$, Optional key$ = "obj") As Object
    p = 1
    token = Tokenize(json)
    Set dic = CreateObject("Scripting.Dictionary")
    If token(p) = "{" Then ParseObj key Else ParseArr key
    Set ParseJSON = dic
End Function

Function ParseObj(key$)
    Do: p = p + 1
        Select Case token(p)
            Case "]"
            Case "[":  ParseArr key
            Case "{"
                       If token(p + 1) = "}" Then
                           p = p + 1
                           dic.Add key, "null"
                       Else
                           ParseObj key
                       End If
            
            Case "}":  key = ReducePath(key): Exit Do
            Case ":":  key = key & "." & token(p - 1)
            Case ",":  key = ReducePath(key)
            Case Else: If token(p + 1) <> ":" Then dic.Add key, token(p)
        End Select
    Loop
End Function

Function ParseArr(key$)
    Dim e&
    Do: p = p + 1
        Select Case token(p)
            Case "}"
            Case "{":  ParseObj key & ArrayID(e)
            Case "[":  ParseArr key
            Case "]":  Exit Do
            Case ":":  key = key & ArrayID(e)
            Case ",":  e = e + 1
            Case Else: dic.Add key & ArrayID(e), token(p)
        End Select
    Loop
End Function

The code above does use a few helper functions, but the above is the meat of it.

The strategy used here is to employ a recursive tokenizer. I found it interesting enough to write an article about this solution on Medium. It explains the details.

Here is the full (yet surprisingly short) code listing, including all of the helper functions:

'-------------------------------------------------------------------
' VBA JSON Parser
'-------------------------------------------------------------------
Option Explicit
Private p&, token, dic
Function ParseJSON(json$, Optional key$ = "obj") As Object
    p = 1
    token = Tokenize(json)
    Set dic = CreateObject("Scripting.Dictionary")
    If token(p) = "{" Then ParseObj key Else ParseArr key
    Set ParseJSON = dic
End Function
Function ParseObj(key$)
    Do: p = p + 1
        Select Case token(p)
            Case "]"
            Case "[":  ParseArr key
            Case "{"
                       If token(p + 1) = "}" Then
                           p = p + 1
                           dic.Add key, "null"
                       Else
                           ParseObj key
                       End If
            
            Case "}":  key = ReducePath(key): Exit Do
            Case ":":  key = key & "." & token(p - 1)
            Case ",":  key = ReducePath(key)
            Case Else: If token(p + 1) <> ":" Then dic.Add key, token(p)
        End Select
    Loop
End Function
Function ParseArr(key$)
    Dim e&
    Do: p = p + 1
        Select Case token(p)
            Case "}"
            Case "{":  ParseObj key & ArrayID(e)
            Case "[":  ParseArr key
            Case "]":  Exit Do
            Case ":":  key = key & ArrayID(e)
            Case ",":  e = e + 1
            Case Else: dic.Add key & ArrayID(e), token(p)
        End Select
    Loop
End Function
'-------------------------------------------------------------------
' Support Functions
'-------------------------------------------------------------------
Function Tokenize(s$)
    Const Pattern = """(([^""\\]|\\.)*)""|[+\-]?(?:0|[1-9]\d*)(?:\.\d*)?(?:[eE][+\-]?\d+)?|\w+|[^\s""']+?"
    Tokenize = RExtract(s, Pattern, True)
End Function
Function RExtract(s$, Pattern, Optional bGroup1Bias As Boolean, Optional bGlobal As Boolean = True)
  Dim c&, m, n, v
  With CreateObject("vbscript.regexp")
    .Global = bGlobal
    .MultiLine = False
    .IgnoreCase = True
    .Pattern = Pattern
    If .TEST(s) Then
      Set m = .Execute(s)
      ReDim v(1 To m.Count)
      For Each n In m
        c = c + 1
        v(c) = n.value
        If bGroup1Bias Then If Len(n.submatches(0)) Or n.value = """""" Then v(c) = n.submatches(0)
      Next
    End If
  End With
  RExtract = v
End Function
Function ArrayID$(e)
    ArrayID = "(" & e & ")"
End Function
Function ReducePath$(key$)
    If InStr(key, ".") Then ReducePath = Left(key, InStrRev(key, ".") - 1)
End Function
Function ListPaths(dic)
    Dim s$, v
    For Each v In dic
        s = s & v & " --> " & dic(v) & vbLf
    Next
    Debug.Print s
End Function
Function GetFilteredValues(dic, match)
    Dim c&, i&, v, w
    v = dic.keys
    ReDim w(1 To dic.Count)
    For i = 0 To UBound(v)
        If v(i) Like match Then
            c = c + 1
            w(c) = dic(v(i))
        End If
    Next
    ReDim Preserve w(1 To c)
    GetFilteredValues = w
End Function
Function GetFilteredTable(dic, cols)
    Dim c&, i&, j&, v, w, z
    v = dic.keys
    z = GetFilteredValues(dic, cols(0))
    ReDim w(1 To UBound(z), 1 To UBound(cols) + 1)
    For j = 1 To UBound(cols) + 1
         z = GetFilteredValues(dic, cols(j - 1))
         For i = 1 To UBound(z)
            w(i, j) = z(i)
         Next
    Next
    GetFilteredTable = w
End Function
Function OpenTextFile$(f)
    With CreateObject("ADODB.Stream")
        .Charset = "utf-8"
        .Open
        .LoadFromFile f
        OpenTextFile = .ReadText
    End With
End Function

What is a quick way to force CRLF in C# / .NET?

Simple variant:

Regex.Replace(input, @"\r\n|\r|\n", "\r\n")

For better performance:

static Regex newline_pattern = new Regex(@"\r\n|\r|\n", RegexOptions.Compiled);
[...]
    newline_pattern.Replace(input, "\r\n");

SqlException from Entity Framework - New transaction is not allowed because there are other threads running in the session

So in the project were I had this exact same issue the problem wasn't in the foreach or the .toList() it was actually in the AutoFac configuration we used. This created some weird situations were the above error was thrown but also a bunch of other equivalent errors were thrown.

This was our fix: Changed this:

container.RegisterType<DataContext>().As<DbContext>().InstancePerLifetimeScope();
container.RegisterType<DbFactory>().As<IDbFactory>().SingleInstance();
container.RegisterType<UnitOfWork>().As<IUnitOfWork>().InstancePerRequest();

To:

container.RegisterType<DataContext>().As<DbContext>().As<DbContext>();
container.RegisterType<DbFactory>().As<IDbFactory>().As<IDbFactory>().InstancePerLifetimeScope();
container.RegisterType<UnitOfWork>().As<IUnitOfWork>().As<IUnitOfWork>();//.InstancePerRequest();

Best lightweight web server (only static content) for Windows

Consider thttpd. It can run under windows.

Quoting wikipedia:

"it is uniquely suited to service high volume requests for static data"

A version of thttpd-2.25b compiled under cygwin with cygwin dll's is available. It is single threaded and particularly good for servicing images.

IOS 7 Navigation Bar text and arrow color

If you're looking to change the title text size and the text color you have to change the NSDictionary titleTextAttributes, for 2 of its objects:

    self.navigationController.navigationBar.titleTextAttributes = [NSDictionary dictionaryWithObjectsAndKeys:[UIFont fontWithName:@"Arial" size:13.0],NSFontAttributeName,
                                                                  [UIColor whiteColor], NSForegroundColorAttributeName, 
                                                                  nil];

Including an anchor tag in an ASP.NET MVC Html.ActionLink

There are overloads of ActionLink which take a fragment parameter. Passing "section12" as your fragment will get you the behavior you're after.

For example, calling LinkExtensions.ActionLink Method (HtmlHelper, String, String, String, String, String, String, Object, Object):

<%= Html.ActionLink("Link Text", "Action", "Controller", null, null, "section12-the-anchor", new { categoryid = "blah"}, null) %>

Understanding the Linux oom-killer's logs

Memory management in Linux is a bit tricky to understand, and I can't say I fully understand it yet, but I'll try to share a little bit of my experience and knowledge.

Short answer to your question: Yes there are other stuff included than whats in the list.

What's being shown in your list is applications run in userspace. The kernel uses memory for itself and modules, on top of that it also has a lower limit of free memory that you can't go under. When you've reached that level it will try to free up resources, and when it can't do that anymore, you end up with an OOM problem.

From the last line of your list you can read that the kernel reports a total-vm usage of: 1498536kB (1,5GB), where the total-vm includes both your physical RAM and swap space. You stated you don't have any swap but the kernel seems to think otherwise since your swap space is reported to be full (Total swap = 524284kB, Free swap = 0kB) and it reports a total vmem size of 1,5GB.

Another thing that can complicate things further is memory fragmentation. You can hit the OOM killer when the kernel tries to allocate lets say 4096kB of continous memory, but there are no free ones availible.

Now that alone probably won't help you solve the actual problem. I don't know if it's normal for your program to require that amount of memory, but I would recommend to try a static code analyzer like cppcheck to check for memory leaks or file descriptor leaks. You could also try to run it through Valgrind to get a bit more information out about memory usage.

How to get a jqGrid cell value when editing

try subscribing to afterEditCell event it will receive (rowid, cellname, value, iRow, iCol) where value is your a new value of your cell

Command for restarting all running docker containers?

If you have docker-compose, all you need to do is:

docker-compose restart 

And you get nice print out of the container's name along with its status of the restart (done/error)

Here is the official guide for installing: https://docs.docker.com/compose/install/

How to set menu to Toolbar in Android

Also you need this, to implement some action to every options of menu.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.menu_help:
            Toast.makeText(this, "This is teh option help", Toast.LENGTH_LONG).show();
            break;
        default:
            break;
    }
    return true;
}

Error in launching AVD with AMD processor

As many other pointed out, Intel HAXM only supports Intel CPUs. Since Windows 1804 you can use Microsoft's Hyper-V instead of HAXM for the emulator. This also helps people who want to use Hyper-V for virtual machines as you need to disable hyper-v to run haxm.

Short version:

  • install Windows Hypervisor Platform feature
  • Update to Android Emulator 27.2.7 or above
  • put WindowsHypervisorPlatform = on into C:\Users\your-username\.android\advancedFeatures.ini or start emulator or command line with -feature WindowsHypervisorPlatform
  • enable IOMMU in your BIOS settings

Long version with more details:

https://blogs.msdn.microsoft.com/visualstudio/2018/05/08/hyper-v-android-emulator-support/

Requirements docs:

https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/system-requirements-for-hyper-v-on-windows

Usage of sys.stdout.flush() method

As per my understanding sys.stdout.flush() pushes out all the data that has been buffered to that point to a file object. While using stdout, data is stored in buffer memory (for some time or until the memory gets filled) before it gets written to terminal. Using flush() forces to empty the buffer and write to terminal even before buffer has empty space.

Java - removing first character of a string

I came across a situation where I had to remove not only the first character (if it was a #, but the first set of characters.

String myString = ###Hello World could be the starting point, but I would only want to keep the Hello World. this could be done as following.

while (myString.charAt(0) == '#') { // Remove all the # chars in front of the real string
    myString = myString.substring(1, myString.length());
}

For OP's case, replace while with if and it works aswell.

No connection could be made because the target machine actively refused it?

It was a silly issue on my side, I had added a defaultproxy to my web.config in order to intercept traffic in Fiddler, and then forgot to remove it!

Open window in JavaScript with HTML inserted

You can also create an "example.html" page which has your desired html and give that page's url as parameter to window.open

var url = '/example.html';
var myWindow = window.open(url, "", "width=800,height=600");

Find all zero-byte files in directory and subdirectories

No, you don't have to bother grep.

find $dir -size 0 ! -name "*.xml"

Using find to locate files that match one of multiple patterns

This works on AIX korn shell.

find *.cbl *.dms -prune -type f -mtime -1

This is looking for *.cbl or *.dms which are 1 day old, in current directory only, skipping the sub-directories.

Limit the height of a responsive image with css

You can use inline styling to limit the height:

<img src="" class="img-responsive" alt="" style="max-height: 400px;">

jQuery Cross Domain Ajax

The response from server is JSON String format. If the set dataType as 'json' jquery will attempt to use it directly. You need to set dataType as 'text' and then parse it manually.

$.ajax({
    type: 'GET',
    dataType: "text", // You need to use dataType text else it will try to parse it.
    url: "http://someotherdomain.com/service.svc",
    success: function (responseData, textStatus, jqXHR) {
        console.log("in");
        var data = JSON.parse(responseData['AuthenticateUserResult']);
        console.log(data);
    },
    error: function (responseData, textStatus, errorThrown) {
        alert('POST failed.');
    }
});

Round a double to 2 decimal places

If you really want the same double, but rounded in the way you want you can use BigDecimal, for example

new BigDecimal(myValue).setScale(2, RoundingMode.HALF_UP).doubleValue();

Split a String into an array in Swift?

Steps to split a string into an array in Swift 4.

  1. assign string
  2. based on @ splitting.

Note: variableName.components(separatedBy: "split keyword")

let fullName: String = "First Last @ triggerd event of the session by session storage @ it can be divided by the event of the trigger."
let fullNameArr = fullName.components(separatedBy: "@")
print("split", fullNameArr)

Heroku 'Permission denied (publickey) fatal: Could not read from remote repository' woes

The problem I was having is that I was only using https for my GitHub account. I needed to make sure that my GitHub account was setup for ssh access and that GitHub and heroku were both using the same public keys. These are the steps I took:

  1. Navigate to the ~/.ssh directory and delete the id_rsa and id_rsa.pub if they are there. I started with new keys, though it might not be necessary.

    $ cd ~/.ssh
    $ rm id_rsa id_rsa.pub
    
  2. Follow the steps on gitHub to generate ssh keys
  3. Login to heroku, create a new site and add your public keys:

    $ heroku login
    ...
    $ heroku create
    $ heroku keys:add
    $ git push heroku master
    

Print string to text file

If you are using Python3.

then you can use Print Function :

your_data = {"Purchase Amount": 'TotalAmount'}
print(your_data,  file=open('D:\log.txt', 'w'))

For python2

this is the example of Python Print String To Text File

def my_func():
    """
    this function return some value
    :return:
    """
    return 25.256


def write_file(data):
    """
    this function write data to file
    :param data:
    :return:
    """
    file_name = r'D:\log.txt'
    with open(file_name, 'w') as x_file:
        x_file.write('{} TotalAmount'.format(data))


def run():
    data = my_func()
    write_file(data)


run()

How to write and read a file with a HashMap?

HashMap implements Serializable so you can use normal serialization to write hashmap to file

Here is the link for Java - Serialization example

Python: Fetch first 10 results from a list

check this

 list = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

 list[0:10]

Outputs:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Passing an array by reference in C?

The C language does not support pass by reference of any type. The closest equivalent is to pass a pointer to the type.

Here is a contrived example in both languages

C++ style API

void UpdateValue(int& i) {
  i = 42;
}

Closest C equivalent

void UpdateValue(int *i) {
  *i = 42;
}

How can I split a shell command over multiple lines when using an IF statement?

The line-continuation will fail if you have whitespace (spaces or tab characters[1]) after the backslash and before the newline. With no such whitespace, your example works fine for me:

$ cat test.sh
if ! fab --fabfile=.deploy/fabfile.py \
   --forward-agent \
   --disable-known-hosts deploy:$target; then
     echo failed
else
     echo succeeded
fi

$ alias fab=true; . ./test.sh
succeeded
$ alias fab=false; . ./test.sh
failed

Some detail promoted from the comments: the line-continuation backslash in the shell is not really a special case; it is simply an instance of the general rule that a backslash "quotes" the immediately-following character, preventing any special treatment it would normally be subject to. In this case, the next character is a newline, and the special treatment being prevented is terminating the command. Normally, a quoted character winds up included literally in the command; a backslashed newline is instead deleted entirely. But otherwise, the mechanism is the same. Most importantly, the backslash only quotes the immediately-following character; if that character is a space or tab, you just get a literal space or tab, and any subsequent newline remains unquoted.

[1] or carriage returns, for that matter, as Czechnology points out. Bash does not get along with Windows-formatted text files, not even in WSL. Or Cygwin, but at least their Bash port has added a set -o igncr option that you can set to make it carriage-return-tolerant.

How to Set Focus on Input Field using JQuery

If the input happens to be in a bootstrap modal dialog, the answer is different. Copying from How to Set focus to first text input in a bootstrap modal after shown this is what is required:

$('#myModal').on('shown.bs.modal', function () {
  $('#textareaID').focus();
})  

How can I access global variable inside class in Python

I understand using a global variable is sometimes the most convenient thing to do, especially in cases where usage of class makes the easiest thing so much harder (e.g., multiprocessing). I ran into the same problem with declaring global variables and figured it out with some experiments.

The reason that g_c was not changed by the run function within your class is that the referencing to the global name within g_c was not established precisely within the function. The way Python handles global declaration is in fact quite tricky. The command global g_c has two effects:

  1. Preconditions the entrance of the key "g_c" into the dictionary accessible by the built-in function, globals(). However, the key will not appear in the dictionary until after a value is assigned to it.

  2. (Potentially) alters the way Python looks for the variable g_c within the current method.

The full understanding of (2) is particularly complex. First of all, it only potentially alters, because if no assignment to the name g_c occurs within the method, then Python defaults to searching for it among the globals(). This is actually a fairly common thing, as is the case of referencing within a method modules that are imported all the way at the beginning of the code.

However, if an assignment command occurs anywhere within the method, Python defaults to finding the name g_c within local variables. This is true even when a referencing occurs before an actual assignment, which will lead to the classic error:

UnboundLocalError: local variable 'g_c' referenced before assignment

Now, if the declaration global g_c occurs anywhere within the method, even after any referencing or assignment, then Python defaults to finding the name g_c within global variables. However, if you are feeling experimentative and place the declaration after a reference, you will be rewarded with a warning:

SyntaxWarning: name 'g_c' is used prior to global declaration

If you think about it, the way the global declaration works in Python is clearly woven into and consistent with how Python normally works. It's just when you actually want a global variable to work, the norm becomes annoying.

Here is a code that summarizes what I just said (with a few more observations):

g_c = 0
print ("Initial value of g_c: " + str(g_c))
print("Variable defined outside of method automatically global? "
      + str("g_c" in globals()))

class TestClass():
    def direct_print(self):
        print("Directly printing g_c without declaration or modification: "
              + str(g_c))
        #Without any local reference to the name
        #Python defaults to search for the variable in globals()
        #This of course happens for all the module names you import

    def mod_without_dec(self):
        g_c = 1
        #A local assignment without declaring reference to global variable
        #makes Python default to access local name
        print ("After mod_without_dec, local g_c=" + str(g_c))
        print ("After mod_without_dec, global g_c=" + str(globals()["g_c"]))


    def mod_with_late_dec(self):
        g_c = 2
        #Even with a late declaration, the global variable is accessed
        #However, a syntax warning will be issued
        global g_c
        print ("After mod_with_late_dec, local g_c=" + str(g_c))
        print ("After mod_with_late_dec, global g_c=" + str(globals()["g_c"]))

    def mod_without_dec_error(self):
        try:
            print("This is g_c" + str(g_c))
        except:
            print("Error occured while accessing g_c")
            #If you try to access g_c without declaring it global
            #but within the method you also alter it at some point
            #then Python will not search for the name in globals()
            #!!!!!Even if the assignment command occurs later!!!!!
        g_c = 3

    def sound_practice(self):
        global g_c
        #With correct declaration within the method
        #The local name g_c becomes an alias for globals()["g_c"]
        g_c = 4
        print("In sound_practice, the name g_c points to: " + str(g_c))


t = TestClass()
t.direct_print()
t.mod_without_dec()
t.mod_with_late_dec()
t.mod_without_dec_error()
t.sound_practice()

align divs to the bottom of their container

Why can't you use absolute positioning? Vertical-align does not work (except for tables). Make your container's position: relative. Then absolutely position the internal divs using bottom: 0; Should work like a charm.

EDIT By zoidberg (i will update the answer instead)

<div style="position:relative; border: 1px solid red;width: 40px; height: 40px;">
   <div style="border:1px solid green;position: absolute; bottom: 0; left: 0; width: 20px; height: 20px;"></div>
   <div style="border:1px solid blue;position: absolute; bottom: 0; left: 20px; width: 20px height: 20px;"></div>
</div>

Javascript array value is undefined ... how do I test for that

This code works very well

function isUndefined(array, index) {
    return ((String(array[index]) == "undefined") ? "Yes" : "No");
}

How to fix "Headers already sent" error in PHP

Generally this error arise when we send header after echoing or printing. If this error arise on a specific page then make sure that page is not echoing anything before calling to start_session().

Example of Unpredictable Error:

 <?php //a white-space before <?php also send for output and arise error
session_start();
session_regenerate_id();

//your page content

One more example:

<?php
includes 'functions.php';
?> <!-- This new line will also arise error -->
<?php
session_start();
session_regenerate_id();

//your page content

Conclusion: Do not output any character before calling session_start() or header() functions not even a white-space or new-line

Declare a variable as Decimal

The best way is to declare the variable as a Single or a Double depending on the precision you need. The data type Single utilizes 4 Bytes and has the range of -3.402823E38 to 1.401298E45. Double uses 8 Bytes.

You can declare as follows:

Dim decAsdf as Single

or

Dim decAsdf as Double

Here is an example which displays a message box with the value of the variable after calculation. All you have to do is put it in a module and run it.

Sub doubleDataTypeExample()
Dim doubleTest As Double


doubleTest = 0.0000045 * 0.005 * 0.01

MsgBox "doubleTest = " & doubleTest
End Sub

What is the difference between include and require in Ruby?

  • Ruby require is more like "include" in other languages (such as C). It tells Ruby that you want to bring in the contents of another file. Similar mechanisms in other languages are:

  • Ruby include is an object-oriented inheritance mechanism used for mixins.

There is a good explanation here:

[The] simple answer is that require and include are essentially unrelated.

"require" is similar to the C include, which may cause newbie confusion. (One notable difference is that locals inside the required file "evaporate" when the require is done.)

The Ruby include is nothing like the C include. The include statement "mixes in" a module into a class. It's a limited form of multiple inheritance. An included module literally bestows an "is-a" relationship on the thing including it.

Emphasis added.

UITableViewCell, show delete button on swipe

I know is old question, but @Kurbz answer just need this for Xcode 6.3.2 and SDK 8.3

I need add [tableView beginUpdates] and [tableView endUpdates] (thanks to @bay.phillips here)

// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle: (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    // Open "Transaction"
    [tableView beginUpdates];

    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // your code goes here
        //add code here for when you hit delete
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
     }

    // Close "Transaction"
    [tableView endUpdates];
}

Spring Boot application.properties value not populating

If you're working in a large multi-module project, with several different application.properties files, then try adding your value to the parent project's property file.

If you are unsure which is your parent project, check your project's pom.xml file, for a <parent> tag.

This solved the issue for me.

.NET DateTime to SqlDateTime Conversion

var sqlCommand = new SqlCommand("SELECT * FROM mytable WHERE start_time >= @StartTime");
sqlCommand.Parameters.Add("@StartTime", SqlDbType.DateTime);
sqlCommand.Parameters("@StartTime").Value = MyDateObj;

Starting a node.js server

Run cmd and then run node server.js. In your example, you are trying to use the REPL to run your command, which is not going to work. The ellipsis is node.js expecting more tokens before closing the current scope (you can type code in and run it on the fly here)

How to set layout_gravity programmatically?

KOTLIN setting more than one gravity on FrameLayout without changing size:

     // assign more than one gravity,Using the operator "or"
    var gravity = Gravity.RIGHT or Gravity.CENTER_VERTICAL
     // update gravity
    (pagerContainer.layoutParams as FrameLayout.LayoutParams).gravity = gravity
     // refresh layout
     pagerContainer.requestLayout()

JavaScript require() on client side

You should look into require.js or head.js for this.

Format JavaScript date as yyyy-mm-dd

This worked for me, and you can paste this directly into your HTML if needed for testing:

<script type="text/javascript">
    if (datefield.type!="date"){ // If the browser doesn't support input type="date",
                                 // initialize date picker widget:
        jQuery(function($){ // On document.ready
            $('#Date').datepicker({
                dateFormat: 'yy-mm-dd', // THIS IS THE IMPORTANT PART!!!
                showOtherMonths: true,
                selectOtherMonths: true,
                changeMonth: true,
                minDate: '2016-10-19',
                maxDate: '2016-11-03'
            });
        })
    }
</script>

Spring can you autowire inside an abstract class?

I have that kind of spring setup working

an abstract class with an autowired field

public abstract class AbstractJobRoute extends RouteBuilder {

    @Autowired
    private GlobalSettingsService settingsService;

and several children defined with @Component annotation.

How to show an alert box in PHP?

echo '<script language="javascript>';

Seems like a simple typo. You're missing a double-quote.

echo '<script language="javascript">';

This should do.

How to make an AlertDialog in Flutter?

Simply used this custom dialog class which field you not needed to leave it or make it null so this customization you got easily.

import 'package:flutter/material.dart';

class CustomAlertDialog extends StatelessWidget {
  final Color bgColor;
  final String title;
  final String message;
  final String positiveBtnText;
  final String negativeBtnText;
  final Function onPostivePressed;
  final Function onNegativePressed;
  final double circularBorderRadius;

  CustomAlertDialog({
    this.title,
    this.message,
    this.circularBorderRadius = 15.0,
    this.bgColor = Colors.white,
    this.positiveBtnText,
    this.negativeBtnText,
    this.onPostivePressed,
    this.onNegativePressed,
  })  : assert(bgColor != null),
        assert(circularBorderRadius != null);

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: title != null ? Text(title) : null,
      content: message != null ? Text(message) : null,
      backgroundColor: bgColor,
      shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(circularBorderRadius)),
      actions: <Widget>[
        negativeBtnText != null
            ? FlatButton(
                child: Text(negativeBtnText),
                textColor: Theme.of(context).accentColor,
                onPressed: () {
                  Navigator.of(context).pop();
                  if (onNegativePressed != null) {
                    onNegativePressed();
                  }
                },
              )
            : null,
        positiveBtnText != null
            ? FlatButton(
                child: Text(positiveBtnText),
                textColor: Theme.of(context).accentColor,
                onPressed: () {
                  if (onPostivePressed != null) {
                    onPostivePressed();
                  }
                },
              )
            : null,
      ],
    );
  }
}

Usage:

var dialog = CustomAlertDialog(
  title: "Logout",
  message: "Are you sure, do you want to logout?",
  onPostivePressed: () {},
  positiveBtnText: 'Yes',
  negativeBtnText: 'No');
showDialog(
  context: context,
  builder: (BuildContext context) => dialog);

Output:

enter image description here