Programs & Examples On #Rank

SQL RANK() over PARTITION on joined tables

As the rank doesn't depend at all from the contacts

RANKED_RSLTS

 QRY_ID  |  RES_ID  |  SCORE |  RANK
-------------------------------------
   A     |    1     |    15  |   3
   A     |    2     |    32  |   1
   A     |    3     |    29  |   2
   C     |    7     |    61  |   1
   C     |    9     |    30  |   2

Thus :

SELECT
    C.*
    ,R.SCORE
    ,MYRANK
FROM CONTACTS C LEFT JOIN
(SELECT  *,
 MYRANK = RANK() OVER (PARTITION BY QRY_ID ORDER BY SCORE DESC)
  FROM RSLTS)  R
ON C.RES_ID = R.RES_ID
AND C.QRY_ID = R.QRY_ID

ROW_NUMBER() in MySQL

This Work perfectly for me to create RowNumber when we have more than one column. In this case two column.

SELECT @row_num := IF(@prev_value= concat(`Fk_Business_Unit_Code`,`NetIQ_Job_Code`), @row_num+1, 1) AS RowNumber, 
    `Fk_Business_Unit_Code`,   
    `NetIQ_Job_Code`,  
    `Supervisor_Name`,  
    @prev_value := concat(`Fk_Business_Unit_Code`,`NetIQ_Job_Code`)  
FROM (SELECT DISTINCT `Fk_Business_Unit_Code`,`NetIQ_Job_Code`,`Supervisor_Name`         
      FROM Employee    
      ORDER BY `Fk_Business_Unit_Code`, `NetIQ_Job_Code`, `Supervisor_Name` DESC) z,  
(SELECT @row_num := 1) x,  
(SELECT @prev_value := '') y  
ORDER BY `Fk_Business_Unit_Code`, `NetIQ_Job_Code`,`Supervisor_Name` DESC

Rank function in MySQL

@Sam, your point is excellent in concept but I think you misunderstood what the MySQL docs are saying on the referenced page -- or I misunderstand :-) -- and I just wanted to add this so that if someone feels uncomfortable with the @Daniel's answer they'll be more reassured or at least dig a little deeper.

You see the "@curRank := @curRank + 1 AS rank" inside the SELECT is not "one statement", it's one "atomic" part of the statement so it should be safe.

The document you reference goes on to show examples where the same user-defined variable in 2 (atomic) parts of the statement, for example, "SELECT @curRank, @curRank := @curRank + 1 AS rank".

One might argue that @curRank is used twice in @Daniel's answer: (1) the "@curRank := @curRank + 1 AS rank" and (2) the "(SELECT @curRank := 0) r" but since the second usage is part of the FROM clause, I'm pretty sure it is guaranteed to be evaluated first; essentially making it a second, and preceding, statement.

In fact, on that same MySQL docs page you referenced, you'll see the same solution in the comments -- it could be where @Daniel got it from; yeah, I know that it's the comments but it is comments on the official docs page and that does carry some weight.

Calculating Covariance with Python and Numpy

Thanks to unutbu for the explanation. By default numpy.cov calculates the sample covariance. To obtain the population covariance you can specify normalisation by the total N samples like this:

Covariance = numpy.cov(a, b, bias=True)[0][1]
print(Covariance)

or like this:

Covariance = numpy.cov(a, b, ddof=0)[0][1]
print(Covariance)

Checking if a folder exists (and creating folders) in Qt, C++

If you need an empty folder you can loop until you get an empty folder

    QString folder= QString ("%1").arg(QDateTime::currentMSecsSinceEpoch());
    while(QDir(folder).exists())
    {
         folder= QString ("%1").arg(QDateTime::currentMSecsSinceEpoch());
    }
    QDir().mkdir(folder);

This case you will get a folder name with a number .

recursion versus iteration

Recursion is usually much slower because all function calls must be stored in a stack to allow the return back to the caller functions. In many cases, memory has to be allocated and copied to implement scope isolation.

Some optimizations, like tail call optimization, make recursions faster but aren't always possible, and aren't implemented in all languages.

The main reasons to use recursion are

  • that it's more intuitive in many cases when it mimics our approach of the problem
  • that some data structures like trees are easier to explore using recursion (or would need stacks in any case)

Of course every recursion can be modeled as a kind of loop : that's what the CPU will ultimately do. And the recursion itself, more directly, means putting the function calls and scopes in a stack. But changing your recursive algorithm to a looping one might need a lot of work and make your code less maintainable : as for every optimization, it should only be attempted when some profiling or evidence showed it to be necessary.

Closure in Java 7

Java Closures are going to be a part of J2SE 8 and is set to be released by the end of 2012.

Java 8's closures support include the concept of Lambda Expressions, Method Reference, Constructor Reference and the Default Methods.

For more information and working examples for this please visit: http://amitrp.blogspot.in/2012/08/at-first-sight-with-closures-in-java.html

What is best tool to compare two SQL Server databases (schema and data)?

I've used SQL Delta before (http://www.sqldelta.com/), it's really good. Not free however, not sure how prices compare to Red-Gates

Reading file from Workspace in Jenkins with Groovy script

May this help to someone if they have the same requirement.

This will read a file that contains the Jenkins Job name and run them iteratively from one single job.

Please change below code accordingly in your Jenkins.

_x000D_
_x000D_
pipeline {
   agent any

   stages {
      stage('Hello') {
         steps {
             script{
            git branch: 'Your Branch name', credentialsId: 'Your crendiatails', url: ' Your BitBucket Repo URL '

##To read file from workspace which will contain the Jenkins Job Name ###
           
     def filePath = readFile "${WORKSPACE}/ Your File Location"                   

##To read file line by line ###
 
     def lines = filePath.readLines() 
      
##To iterate and run Jenkins Jobs one by one ####

                    for (line in lines) {                                            
                      build(job: "$line/branchName",
                        parameters:
                        [string(name: 'vertical', value: "${params.vert}"),
                        string(name: 'environment', value: "${params.env}"),
                        string(name: 'branch', value: "${params.branch}"),
                        string(name: 'project', value: "${params.project}")
                        ]
                    )
                        }  
                                       }
                    
         }
         }
      }
   }
_x000D_
_x000D_
_x000D_

How can I find which tables reference a given table in Oracle SQL Developer?

How about something like this:

SELECT c.constraint_name, c.constraint_type, c2.constraint_name, c2.constraint_type, c2.table_name
  FROM dba_constraints c JOIN dba_constraints c2 ON (c.r_constraint_name = c2.constraint_name)
 WHERE c.table_name = <TABLE_OF_INTEREST>
   AND c.constraint_TYPE = 'R';

How to terminate a python subprocess launched with shell=True

When shell=True the shell is the child process, and the commands are its children. So any SIGTERM or SIGKILL will kill the shell but not its child processes, and I don't remember a good way to do it. The best way I can think of is to use shell=False, otherwise when you kill the parent shell process, it will leave a defunct shell process.

What is the difference between atan and atan2 in C++?

In atan2, the output is: -pi < atan2(y,x) <pi
and in atan, the output is: -pi/2 < atan(y/x) < pi/2 //it dose NOT consider the quarter.
If you want to get the orientation between 0 and 2*pi (like the high-school math), we need to use the atan2 and for negative values add the 2*pi to get the final result between 0 and 2*pi.
Here is the Java source code to explain it clearly:

System.out.println(Math.atan2(1,1)); //pi/4 in the 1st quarter
System.out.println(Math.atan2(1,-1)); //(pi/4)+(pi/2)=3*(pi/4) in the 2nd quarter

System.out.println(Math.atan2(-1,-1 ));//-3*(pi/4) and it is less than 0.
System.out.println(Math.atan2(-1,-1)+2*Math.PI); //5(pi/4) in the 3rd quarter

System.out.println(Math.atan2(-1,1 ));//-pi/4 and it is less than 0.
System.out.println(Math.atan2(-1,1)+2*Math.PI); //7*(pi/4) in the 4th quarter

System.out.println(Math.atan(1 ));//pi/4
System.out.println(Math.atan(-1 ));//-pi/4

Delete topic in Kafka 0.8.1.1

If you have issues deleting the topics, try to delete the topic using:

$KAFKA_HOME/bin/kafka-topics.sh --delete --zookeeper localhost:2181 --topic your_topic_name

command. Then in order to verify the deletion process, go to the kafka logs directory which normally is placed under /tmp/kafka-logs/, then delete the your_topic_name file via rm -rf your_topic_name command.

Remember to monitor the whole process via a kafka management tool like Kafka Tool.

The mentioned process above will remove the topics without kafka server restart.

Clear the cache in JavaScript

Cause browser cache same link, you should add a random number end of the url. new Date().getTime() generate a different number.

Just add new Date().getTime() end of link as like call

'https://stackoverflow.com/questions.php?' + new Date().getTime()

Output: https://stackoverflow.com/questions.php?1571737901173

Unix command-line JSON parser?

Anyone mentioned Jshon or JSON.sh?

https://github.com/keenerd/jshon

pipe json to it, and it traverses the json objects and prints out the path to the current object (as a JSON array) and then the object, without whitespace.

http://kmkeen.com/jshon/
Jshon loads json text from stdin, performs actions, then displays the last action on stdout and also was made to be part of the usual text processing pipeline.

How to return images in flask response?

You use something like

from flask import send_file

@app.route('/get_image')
def get_image():
    if request.args.get('type') == '1':
       filename = 'ok.gif'
    else:
       filename = 'error.gif'
    return send_file(filename, mimetype='image/gif')

to send back ok.gif or error.gif, depending on the type query parameter. See the documentation for the send_file function and the request object for more information.

How can I delete one element from an array by value

I like the -=[4] way mentioned in other answers to delete the elements whose value is 4.

But there is this way:

[2,4,6,3,8,6].delete_if { |i| i == 6 }
=> [2, 4, 3, 8]

mentioned somewhere in "Basic Array Operations", after it mentions the map function.

How can I increase the size of a bootstrap button?

Default Bootstrap size classes

You can use btn-lg, btn-sm and btn-xs classes for manipulating with its size.

btn-block

Also, there is a class btn-block which will extend your button to the whole block. It is very convenient in combination with Bootstrap grid.
For example, this code will show a button with the width equal to half of screen for medium and large screens; and will show a full-width button for small screens:

<div class="container">
    <div class="col-xs-12 col-xs-offset-0 col-sm-offset-3 col-sm-6">
        <button class="btn btn-group">Click me!</button>
    </div>
</div>

Check this JSFiddle out. Try to resize frame.

If it is not enough, you can easily create your custom class.

How to make two plots side-by-side using Python?

You can use - matplotlib.gridspec.GridSpec

Check - https://matplotlib.org/stable/api/_as_gen/matplotlib.gridspec.GridSpec.html

The below code displays a heatmap on right and an Image on left.

#Creating 1 row and 2 columns grid
gs = gridspec.GridSpec(1, 2) 
fig = plt.figure(figsize=(25,3))

#Using the 1st row and 1st column for plotting heatmap
ax=plt.subplot(gs[0,0])
ax=sns.heatmap([[1,23,5,8,5]],annot=True)

#Using the 1st row and 2nd column to show the image
ax1=plt.subplot(gs[0,1])
ax1.grid(False)
ax1.set_yticklabels([])
ax1.set_xticklabels([])

#The below lines are used to display the image on ax1
image = io.imread("https://images-na.ssl-images- amazon.com/images/I/51MvhqY1qdL._SL160_.jpg")

plt.imshow(image)
plt.show()

Output image

The name 'ConfigurationManager' does not exist in the current context

To Solve this problem go to Solution Explorer And right click reference and click add reference and chose .net and find system.configuration select an click ok

Java: Multiple class declarations in one file

I believe you simply call PrivateImpl what it is: a non-public top-level class. You can also declare non-public top-level interfaces as well.

e.g., elsewhere on SO: Non-public top-level class vs static nested class

As for changes in behavior between versions, there was this discussion about something that "worked perfectly" in 1.2.2. but stopped working in 1.4 in sun's forum: Java Compiler - unable to declare a non public top level classes in a file.

applying css to specific li class

You are defining the color: #C1C1C1; for all the a elements with #sub-nav-container a.

Doing it again in li.sub-navigation-home-news won't do anything, as it is a parent of the a element.

AFNetworking Post Request

For AFNetworking 4

AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
NSDictionary *params = @{@"user[height]": height,
                         @"user[weight]": weight};
[manager POST:@"https://example.com/myobject" parameters:params headers:nil progress:nil success:^(NSURLSessionTask *task, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
} failure:^(NSURLSessionTask *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];

What datatype should be used for storing phone numbers in SQL Server 2005?

Use SSIS to extract and process the information. That way you will have the processing of the XML files separated from SQL Server. You can also do the SSIS transformations on a separate server if needed. Store the phone numbers in a standard format using VARCHAR. NVARCHAR would be unnecessary since we are talking about numbers and maybe a couple of other chars, like '+', ' ', '(', ')' and '-'.

I can't access http://localhost/phpmyadmin/

You should use localhost:portnumber/phpmyadmin Here the Portnumber is the number which you set for your web server or if you have not set it until now it is by Default - 80.

Enable tcp\ip remote connections to sql server express already installed database with code or script(query)

I tested below code with SQL Server 2008 R2 Express and I believe we should have solution for all 6 steps you outlined. Let's take on them one-by-one:

1 - Enable TCP/IP

We can enable TCP/IP protocol with WMI:

set wmiComputer = GetObject( _
    "winmgmts:" _
    & "\\.\root\Microsoft\SqlServer\ComputerManagement10")
set tcpProtocols = wmiComputer.ExecQuery( _
    "select * from ServerNetworkProtocol " _
    & "where InstanceName = 'SQLEXPRESS' and ProtocolName = 'Tcp'")

if tcpProtocols.Count = 1 then
    ' set tcpProtocol = tcpProtocols(0)
    ' I wish this worked, but unfortunately 
    ' there's no int-indexed Item property in this type

    ' Doing this instead
    for each tcpProtocol in tcpProtocols
        dim setEnableResult
            setEnableResult = tcpProtocol.SetEnable()
            if setEnableResult <> 0 then 
                Wscript.Echo "Failed!"
            end if
    next
end if

2 - Open the right ports in the firewall

I believe your solution will work, just make sure you specify the right port. I suggest we pick a different port than 1433 and make it a static port SQL Server Express will be listening on. I will be using 3456 in this post, but please pick a different number in the real implementation (I feel that we will see a lot of applications using 3456 soon :-)

3 - Modify TCP/IP properties enable a IP address

We can use WMI again. Since we are using static port 3456, we just need to update two properties in IPAll section: disable dynamic ports and set the listening port to 3456:

set wmiComputer = GetObject( _
    "winmgmts:" _
    & "\\.\root\Microsoft\SqlServer\ComputerManagement10")
set tcpProperties = wmiComputer.ExecQuery( _
    "select * from ServerNetworkProtocolProperty " _
    & "where InstanceName='SQLEXPRESS' and " _
    & "ProtocolName='Tcp' and IPAddressName='IPAll'")

for each tcpProperty in tcpProperties
    dim setValueResult, requestedValue

    if tcpProperty.PropertyName = "TcpPort" then
        requestedValue = "3456"
    elseif tcpProperty.PropertyName ="TcpDynamicPorts" then
        requestedValue = ""
    end if

    setValueResult = tcpProperty.SetStringValue(requestedValue)
    if setValueResult = 0 then 
        Wscript.Echo "" & tcpProperty.PropertyName & " set."
    else
        Wscript.Echo "" & tcpProperty.PropertyName & " failed!"
    end if
next

Note that I didn't have to enable any of the individual addresses to make it work, but if it is required in your case, you should be able to extend this script easily to do so.

Just a reminder that when working with WMI, WBEMTest.exe is your best friend!

4 - Enable mixed mode authentication in sql server

I wish we could use WMI again, but unfortunately this setting is not exposed through WMI. There are two other options:

  1. Use LoginMode property of Microsoft.SqlServer.Management.Smo.Server class, as described here.

  2. Use LoginMode value in SQL Server registry, as described in this post. Note that by default the SQL Server Express instance is named SQLEXPRESS, so for my SQL Server 2008 R2 Express instance the right registry key was HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQLServer.

5 - Change user (sa) default password

You got this one covered.

6 - Finally (connect to the instance)

Since we are using a static port assigned to our SQL Server Express instance, there's no need to use instance name in the server address anymore.

SQLCMD -U sa -P newPassword -S 192.168.0.120,3456

Please let me know if this works for you (fingers crossed!).

Why is my xlabel cut off in my matplotlib plot?

plt.autoscale() worked for me.

Replace preg_replace() e modifier with preg_replace_callback

In a regular expression, you can "capture" parts of the matched string with (brackets); in this case, you are capturing the (^|_) and ([a-z]) parts of the match. These are numbered starting at 1, so you have back-references 1 and 2. Match 0 is the whole matched string.

The /e modifier takes a replacement string, and substitutes backslash followed by a number (e.g. \1) with the appropriate back-reference - but because you're inside a string, you need to escape the backslash, so you get '\\1'. It then (effectively) runs eval to run the resulting string as though it was PHP code (which is why it's being deprecated, because it's easy to use eval in an insecure way).

The preg_replace_callback function instead takes a callback function and passes it an array containing the matched back-references. So where you would have written '\\1', you instead access element 1 of that parameter - e.g. if you have an anonymous function of the form function($matches) { ... }, the first back-reference is $matches[1] inside that function.

So a /e argument of

'do_stuff(\\1) . "and" . do_stuff(\\2)'

could become a callback of

function($m) { return do_stuff($m[1]) . "and" . do_stuff($m[2]); }

Or in your case

'strtoupper("\\2")'

could become

function($m) { return strtoupper($m[2]); }

Note that $m and $matches are not magic names, they're just the parameter name I gave when declaring my callback functions. Also, you don't have to pass an anonymous function, it could be a function name as a string, or something of the form array($object, $method), as with any callback in PHP, e.g.

function stuffy_callback($things) {
    return do_stuff($things[1]) . "and" . do_stuff($things[2]);
}
$foo = preg_replace_callback('/([a-z]+) and ([a-z]+)/', 'stuffy_callback', 'fish and chips');

As with any function, you can't access variables outside your callback (from the surrounding scope) by default. When using an anonymous function, you can use the use keyword to import the variables you need to access, as discussed in the PHP manual. e.g. if the old argument was

'do_stuff(\\1, $foo)'

then the new callback might look like

function($m) use ($foo) { return do_stuff($m[1], $foo); }

Gotchas

  • Use of preg_replace_callback is instead of the /e modifier on the regex, so you need to remove that flag from your "pattern" argument. So a pattern like /blah(.*)blah/mei would become /blah(.*)blah/mi.
  • The /e modifier used a variant of addslashes() internally on the arguments, so some replacements used stripslashes() to remove it; in most cases, you probably want to remove the call to stripslashes from your new callback.

When using .net MVC RadioButtonFor(), how do you group so only one selection can be made?

In my case, I had a collection of radio buttons that needed to be in a group. I just included a 'Selected' property in the model. Then, in the loop to output the radiobuttons just do...

@Html.RadioButtonFor(m => Model.Selected, Model.Categories[i].Title)

This way, the name is the same for all radio buttons. When the form is posted, the 'Selected' property is equal to the category title (or id or whatever) and this can be used to update the binding on the relevant radiobutton, like this...

model.Categories.Find(m => m.Title.Equals(model.Selected)).Selected = true;

May not be the best way, but it does work.

Possible to perform cross-database queries with PostgreSQL?

If performance is important and most queries are read-only, I would suggest to replicate data over to another database. While this seems like unneeded duplication of data, it might help if indexes are required.

This can be done with simple on insert triggers which in turn call dblink to update another copy. There are also full-blown replication options (like Slony) but that's off-topic.

How to return a value from try, catch, and finally?

The problem is what happens when you get NumberFormatexception thrown? You print it and return nothing.

Note: You don't need to catch and throw an Exception back. Usually it is done to wrap it or print stack trace and ignore for example.

catch(RangeException e) {
     throw e;
}

How to remove the first and the last character of a string

You could regex it:

"string".replace(/^\/?|\/?$/, "")
"/installers/services/".replace(/^\/?|\/?$/, "") // -> installers/services

The regex explained:
- Optional first slash: ^/?, escaped -> ^\/? (the ^ means beginning of string)
- The pipe ( | ) can be read as or
- Than the option slash at the end -> /?$, escaped -> \/?$ ( the $ means end of string)

Combined it would be ^/?|/$ without escaping. Optional first slash OR optional last slash

Why use String.Format?

One reason it is not preferable to write the string like 'string +"Value"+ string' is because of Localization. In cases where localization is occurring we want the localized string to be correctly formatted, which could be very different from the language being coded in.

For example we need to show the following error in different languages:

MessageBox.Show(String.Format(ErrorManager.GetError("PIDV001").Description, proposalvalue.ProposalSource)

where

'ErrorCollector.GetError("ERR001").ErrorDescription' returns a string like "Your ID {0} is not valid". This message must be localized in many languages. In that case we can't use + in C#. We need to follow string.format.

In Bootstrap 3,How to change the distance between rows in vertical?

Instead of adding any tag which is never a good solution. You can always use margin property with the required element.

You can add the margin on row class itself. So it will affect globally.

.row{
  margin-top: 30px;
  margin-bottom: 30px
}

Update: Better solution in all cases would be to introduce a new class and then use it along with .row class.

.row-m-t{
  margin-top : 20px
}

Then use it wherever you want

<div class="row row-m-t"></div>

Measuring text height to be drawn on Canvas ( Android )

You could use the android.text.StaticLayout class to specify the bounds required and then call getHeight(). You can draw the text (contained in the layout) by calling its draw(Canvas) method.

Tool to monitor HTTP, TCP, etc. Web Service traffic

I've been using Charles for the last couple of years. Very pleased with it.

Rails: Missing host to link to! Please provide :host parameter or set default_url_options[:host]

You can set default url options in the Application Controller:

class ApplicationController < ActionController::Base
  def default_url_options
    {:locale => I18n.locale}
  end
end

http://guides.rubyonrails.org/action_controller_overview.html#default_url_options

Eclipse: Syntax Error, parameterized types are only if source level is 1.5

My guess would be that while you run eclipse itself with JDK 1.6, it's actually configured with a different default jre.

See Window->preferences->java->Installed JREs and make sure that the checked JRE is 1.6.

If the default JRE is indeed 1.6, chances are that it's a project specific setting. See that the project is configured to use the right JRE.

Bootstrap modal: is not a function

The problem happened to me just in production just because I imported jquery with HTTP and not HTTPS (and production is HTTPS)

Auto detect mobile browser (via user-agent?)

Yes user-agent is used to detect mobile browsers. There are lots of free scripts available to check this. Here is one such php code which will help you redirect mobile users to different website.

PostgreSQL: Show tables in PostgreSQL


Using psql : \dt

Or:

SELECT c.relname AS Tables_in FROM pg_catalog.pg_class c
        LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE pg_catalog.pg_table_is_visible(c.oid)
        AND c.relkind = 'r'
        AND relname NOT LIKE 'pg_%'
ORDER BY 1

How to log cron jobs?

* * * * * myjob.sh >> /var/log/myjob.log 2>&1

will log all output from the cron job to /var/log/myjob.log

You might use mail to send emails. Most systems will send unhandled cron job output by email to root or the corresponding user.

Replacing few values in a pandas dataframe column with another value

The easiest way is to use the replace method on the column. The arguments are a list of the things you want to replace (here ['ABC', 'AB']) and what you want to replace them with (the string 'A' in this case):

>>> df['BrandName'].replace(['ABC', 'AB'], 'A')
0    A
1    B
2    A
3    D
4    A

This creates a new Series of values so you need to assign this new column to the correct column name:

df['BrandName'] = df['BrandName'].replace(['ABC', 'AB'], 'A')

How do I switch between command and insert mode in Vim?

You can use Alt+H,J,K,L to move cursor in insert mode.

How can I correctly format currency using jquery?

Another option (If you are using ASP.Net razor view) is, On your view you can do

<div>@String.Format("{0:C}", Model.total)</div>

This would format it correctly. note (item.total is double/decimal)

if in jQuery you can also use Regex

$(".totalSum").text('$' + parseFloat(total, 10).toFixed(2).replace(/(\d)(?=(\d{3})+\.)/g, "$1,").toString());

How do I set the time zone of MySQL?

First to figure out what the time_zone is you can query

SHOW VARIABLES LIKE '%time_zone%'; 

Your output should be something similar as follows

**Variable_name**     **Value**
system_time_zone      CDT
time_zone             SYSTEM

Then if you want to confirm that you are in say some time zone like CDT instead of something like EST you can check what time it thinks your machine is in by saying

SELECT NOW();

If this is not the time you want you need to change it... all you need to do is SET time_zone = timezone_name. Make sure it is one that is in Continent/City format.

If you are on a shared server because you have a hosting service please refer to these answers regarding changing the php.ini file or the .htaccess file.

Proper use of errors

The convention for out of range in JavaScript is using RangeError. To check the type use if / else + instanceof starting at the most specific to the most generic

try {
    throw new RangeError();
}
catch (e){
    if (e instanceof RangeError){
        console.log('out of range');
    } else { 
        throw; 
    }
}

SQL Network Interfaces, error: 50 - Local Database Runtime error occurred. Cannot create an automatic instance

Breaking Changes to LocalDB: Applies to SQL 2014; take a look over this article and try to use (localdb)\mssqllocaldb as server name to connect to the LocalDB automatic instance, for example:

<connectionStrings>
  <add name="ProductsContext" connectionString="Data Source=(localdb)\mssqllocaldb; 
  ...

The article also mentions the use of 2012 SSMS to connect to the 2014 LocalDB. Which leads me to believe that you might have multiple versions of SQL installed - which leads me to point out this SO answer that suggests changing the default name of your LocalDB "instance" to avoid other version mismatch issues that might arise going forward; mentioned not as source of issue, but to raise awareness of potential clashes that multiple SQL version installed on a single dev machine might lead to ... and something to get in the habit of in order to avoid some.

Another thing worth mentioning - if you've gotten your instance in an unusable state due to tinkering with it to try and fix this problem, then it might be worth starting over - uninstall, reinstall - then try using the mssqllocaldb value instead of v12.0 and see if that corrects your issue.

How to semantically add heading to a list

In this case I would use a definition list as so:

<dl>
  <dt>Fruits I like:</dt>
  <dd>Apples</dd>
  <dd>Bananas</dd>
  <dd>Oranges</dd>
</dl>

How to empty a Heroku database

Now it's also possible to reset the database through their web interface.

Go to dashboard.heroku.com select your app and then you'll find the database under the add-ons category, click on it and then you can reset the database.

Reset Heroku Database

SQL Case Expression Syntax?

Here you can find a complete guide for MySQL case statements in SQL.

CASE
     WHEN some_condition THEN return_some_value
     ELSE return_some_other_value
END

Numpy first occurrence of value greater than existing value

I'd like to propose

np.min(np.append(np.where(aa>5)[0],np.inf))

This will return the smallest index where the condition is met, while returning infinity if the condition is never met (and where returns an empty array).

How to delete the last row of data of a pandas dataframe

Surprised nobody brought this one up:

# To remove last n rows
df.head(-n)

# To remove first n rows
df.tail(-n)

Running a speed test on a DataFrame of 1000 rows shows that slicing and head/tail are ~6 times faster than using drop:

>>> %timeit df[:-1]
125 µs ± 132 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)

>>> %timeit df.head(-1)
129 µs ± 1.18 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

>>> %timeit df.drop(df.tail(1).index)
751 µs ± 20.4 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

How to add a hook to the application context initialization event?

Since Spring 4.2 you can use @EventListener (documentation)

@Component
class MyClassWithEventListeners {

    @EventListener({ContextRefreshedEvent.class})
    void contextRefreshedEvent() {
        System.out.println("a context refreshed event happened");
    }
}

cannot import name patterns

I Resolved it by cloning my project directly into Eclipse from GIT,

Initially I was cloning it at specific location on file system then importing it as existing project into Eclipse.

Changing CSS for last <li>

:last-child is really the only way to do it without modifying the HTML - but assuming you can do that, the main option is just to give it a class="last-item", then do:

li.last-item { /* ... */ }

Obviously, you can automate this in the dynamic page generation language of your choice. Also, there is a lastChild JavaScript property in the W3C DOM.

Here's an example of doing what you want in Prototype:

$$("ul").each(function(x) { $(x.lastChild).addClassName("last-item"); });

Or even more simply:

$$("ul li:last-child").each(function(x) { x.addClassName("last-item"); });

In jQuery, you can write it even more compactly:

$("ul li:last-child").addClass("last-item");

Also note that this should work without using the actual last-child CSS selector - rather, a JavaScript implementation of it is used - so it should be less buggy and more reliable across browsers.

jQuery UI Dialog with ASP.NET button postback

Primarily it's because jQuery moves the dialog outside of the form tags using the DOM. Move it back inside the form tags and it should work fine. You can see this by inspecting the element in Firefox.

Dockerfile copy keep subdirectory structure

Alternatively you can use a "." instead of *, as this will take all the files in the working directory, include the folders and subfolders:

FROM ubuntu
COPY . /
RUN ls -la /

Delete rows containing specific strings in R

Actually I would use:

df[ grep("REVERSE", df$Name, invert = TRUE) , ]

This will avoid deleting all of the records if the desired search word is not contained in any of the rows.

How to work with progress indicator in flutter?

Step 1: Create Dialog

   showAlertDialog(BuildContext context){
      AlertDialog alert=AlertDialog(
        content: new Row(
            children: [
               CircularProgressIndicator(),
               Container(margin: EdgeInsets.only(left: 5),child:Text("Loading" )),
            ],),
      );
      showDialog(barrierDismissible: false,
        context:context,
        builder:(BuildContext context){
          return alert;
        },
      );
    }

Step 2:Call it

showAlertDialog(context);
await firebaseAuth.signInWithEmailAndPassword(email: email, password: password);
Navigator.pop(context);

Example With Dialog and login form

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
class DynamicLayout extends StatefulWidget{
  @override
  State<StatefulWidget> createState() {
    // TODO: implement createState
    return new MyWidget();
    }
  }
showAlertDialog(BuildContext context){
  AlertDialog alert=AlertDialog(
    content: new Row(
        children: [
           CircularProgressIndicator(),
           Container(margin: EdgeInsets.only(left: 5),child:Text("Loading" )),
        ],),
  );
  showDialog(barrierDismissible: false,
    context:context,
    builder:(BuildContext context){
      return alert;
    },
  );
}

  class MyWidget extends State<DynamicLayout>{
  Color color = Colors.indigoAccent;
  String title='app';
  GlobalKey<FormState> globalKey=GlobalKey<FormState>();
  String email,password;
  login() async{
   var currentState= globalKey.currentState;
   if(currentState.validate()){
        currentState.save();
        FirebaseAuth firebaseAuth=FirebaseAuth.instance;
        try {
          showAlertDialog(context);
          AuthResult authResult=await firebaseAuth.signInWithEmailAndPassword(
              email: email, password: password);
          FirebaseUser user=authResult.user;
          Navigator.pop(context);
        }catch(e){
          print(e);
        }
   }else{

   }
  }
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar:AppBar(
        title: Text("$title"),
        ) ,
          body: Container(child: Form(
            key: globalKey,
            child: Container(
              padding: EdgeInsets.all(10),
              child: Column(children: <Widget>[
              TextFormField(decoration: InputDecoration(icon: Icon(Icons.email),labelText: 'Email'),
              // ignore: missing_return
              validator:(val){
                if(val.isEmpty)
                  return 'Please Enter Your Email';
              },
              onSaved:(val){
                email=val;
              },
              ),
                TextFormField(decoration: InputDecoration(icon: Icon(Icons.lock),labelText: 'Password'),
             obscureText: true,
                  // ignore: missing_return
                  validator:(val){
                    if(val.isEmpty)
                      return 'Please Enter Your Password';
                  },
                  onSaved:(val){
                    password=val;
                  },
              ),
                RaisedButton(color: Colors.lightBlue,textColor: Colors.white,child: Text('Login'),
                  onPressed:login),
            ],)
              ,),)
         ),
    );
  }
}

enter image description here

Where can I set environment variables that crontab will use?

Whatever you set in crontab will be available in the cronjobs, both directly and using the variables in the scripts.

Use them in the definition of the cronjob

You can configure crontab so that it sets variables that then the can cronjob use:

$ crontab -l
myvar="hi man"
* * * * * echo "$myvar. date is $(date)" >> /tmp/hello

Now the file /tmp/hello shows things like:

$ cat /tmp/hello 
hi man. date is Thu May 12 12:10:01 CEST 2016
hi man. date is Thu May 12 12:11:01 CEST 2016

Use them in the script run by cronjob

You can configure crontab so that it sets variables that then the scripts can use:

$ crontab -l
myvar="hi man"
* * * * * /bin/bash /tmp/myscript.sh

And say script /tmp/myscript.sh is like this:

echo "Now is $(date). myvar=$myvar" >> /tmp/myoutput.res

It generates a file /tmp/myoutput.res showing:

$ cat /tmp/myoutput.res
Now is Thu May 12 12:07:01 CEST 2016. myvar=hi man
Now is Thu May 12 12:08:01 CEST 2016. myvar=hi man
...

Adjusting and image Size to fit a div (bootstrap)

Just a heads up that Bootstrap 4 now uses img-fluid instead of img-responsive, so double check which version you're using if you're having problems.

What’s the best way to reload / refresh an iframe?

Another solution.

const frame = document.getElementById("my-iframe");

frame.parentNode.replaceChild(frame.cloneNode(), frame);

Django: TemplateSyntaxError: Could not parse the remainder

This error usually means you've forgotten a closing quote somewhere in the template you're trying to render. For example: {% url 'my_view %} (wrong) instead of {% url 'my_view' %} (correct). In this case it's the colon that's causing the problem. Normally you'd edit the template to use the correct {% url %} syntax.

But there's no reason why the django admin site would throw this, since it would know it's own syntax. My best guess is therefore that grapelli is causing your problem since it changes the admin templates. Does removing grappelli from installed apps help?

Check if SQL Connection is Open or Closed

This code is a little more defensive, before opening a connection, check state. If connection state is Broken then we should try to close it. Broken means that the connection was previously opened and not functioning correctly. The second condition determines that connection state must be closed before attempting to open it again so the code can be called repeatedly.

// Defensive database opening logic.

if (_databaseConnection.State == ConnectionState.Broken) {
    _databaseConnection.Close();
}

if (_databaseConnection.State == ConnectionState.Closed) {
    _databaseConnection.Open();
}

HTTP Error 404 when running Tomcat from Eclipse

It is because there is no default ROOT web application. When you create some web app and deploy it to Tomcat using Eclipse, then you will be able to access it with the URL in the form of

http://localhost:8080/YourWebAppName

where YourWebAppName is some name you give to your web app (the so called application context path).

Quote from Jetty Documentation Wiki (emphasis mine):

The context path is the prefix of a URL path that is used to select the web application to which an incoming request is routed. Typically a URL in a Java servlet server is of the format http://hostname.com/contextPath/servletPath/pathInfo, where each of the path elements may be zero or more / separated elements. If there is no context path, the context is referred to as the root context.


If you still want the default app which is accessed with the URL of the form

http://localhost:8080

or if you change the default 8080 port to 80, then just

http://localhost

i.e. without application context path read the following (quote from Tutorial: Installing Tomcat 7 and Using it with Eclipse, emphasis mine):

Copy the ROOT (default) Web app into Eclipse. Eclipse forgets to copy the default apps (ROOT, examples, docs, etc.) when it creates a Tomcat folder inside the Eclipse workspace. Go to C:\apache-tomcat-7.0.34\webapps and copy the ROOT folder. Then go to your Eclipse workspace, go to the .metadata folder, and search for "wtpwebapps". You should find something like C:\your-eclipse-workspace-location\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps (or .../tmp1/wtpwebapps if you already had another server registered in Eclipse). Go to the wtpwebapps folder and paste ROOT (say "yes" if asked if you want to merge/replace folders/files). Then reload http://localhost/ to see the Tomcat welcome page.

Replacement for "rename" in dplyr

The next version of dplyr will support an improved version of select that also incorporates renaming:

> mtcars2 <- select( mtcars, disp2 = disp )
> head( mtcars2 )
                  disp2
Mazda RX4         160
Mazda RX4 Wag     160
Datsun 710        108
Hornet 4 Drive    258
Hornet Sportabout 360
Valiant           225
> changes( mtcars, mtcars2 )
Changed variables:
      old         new
disp  0x105500400
disp2             0x105500400

Changed attributes:
      old         new
names 0x106d2cf50 0x106d28a98

Installing PIL (Python Imaging Library) in Win7 64 bits, Python 2.6.4

I was having the same problem so I decided to download the source kit and install it according to how you posted above...

  1. Downloaded Source Kit
  2. Opened command prompt on that folder and typed python setup.py build
  3. Then I typed python setup.py install

It worked perfectly!

Now, some notes: when I typed python setup.py build, I saw that Microsoft Visual Studio v9.0 C compiler was being used to build everything.

So probably it's something with your compiler not correctly configured or something...

Anyways, that worked with me so thank you!

String.Format for Hex

You can also pad the characters left by including a number following the X, such as this: string.format("0x{0:X8}", string_to_modify), which yields "0x00000C20".

Multiple condition in single IF statement

Yes it is, there have to be boolean expresion after IF. Here you have a direct link. I hope it helps. GL!

Getting full-size profile picture

found a way:

$albums = $facebook->api('/' . $user_id . '/albums');
foreach($albums['data'] as $album){
    if ($album['name'] == "Profile Pictures"){
        $photos = $facebook->api('/' . $album['id'] . '/photos');
        $profile_pic = $photos['data'][0]['source'];
        break;
    }
}

HTML 5 Video "autoplay" not automatically starting in CHROME

Here is it: http://www.htmlcssvqs.com/8ed/examples/chapter-17/webm-video-with-autoplay-loop.html You have to add the tags: autoplay="autoplay" loop="loop" or just "autoplay" and "loop".

access key and value of object using *ngFor

You could create a custom pipe to return the list of key for each element. Something like that:

import { PipeTransform, Pipe } from '@angular/core';

@Pipe({name: 'keys'})
export class KeysPipe implements PipeTransform {
  transform(value, args:string[]) : any {
    let keys = [];
    for (let key in value) {
      keys.push(key);
    }
    return keys;
  }
}

and use it like that:

<tr *ngFor="let c of content">           
  <td *ngFor="let key of c | keys">{{key}}: {{c[key]}}</td>
</tr>

Edit

You could also return an entry containing both key and value:

@Pipe({name: 'keys'})
export class KeysPipe implements PipeTransform {
  transform(value, args:string[]) : any {
    let keys = [];
    for (let key in value) {
      keys.push({key: key, value: value[key]});
    }
    return keys;
  }
}

and use it like that:

<span *ngFor="let entry of content | keys">           
  Key: {{entry.key}}, value: {{entry.value}}
</span>

mongodb, replicates and error: { "$err" : "not master and slaveOk=false", "code" : 13435 }

THIS IS JUST A NOTE FOR ANYONE DEALING WITH THIS PROBLEM USING THE RUBY DRIVER

I had this same problem when using the Ruby Gem.

To set slaveOk in Ruby, you just pass it as an argument when you create the client like this:

mongo_client = MongoClient.new("localhost", 27017, { slave_ok: true })

https://github.com/mongodb/mongo-ruby-driver/wiki/Tutorial#making-a-connection

mongo_client = MongoClient.new # (optional host/port args)

Notice that 'args' is the third optional argument.

How can I use inverse or negative wildcards when pattern matching in a unix/linux shell?

this would do it excluding exactly 'Music'

cp -a ^'Music' /target

this and that for excluding things like Music?* or *?Music

cp -a ^\*?'complete' /target
cp -a ^'complete'?\* /target

Retrieve data from website in android app

Use this

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet("http://www.someplace.com");
ResponseHandler<String> resHandler = new BasicResponseHandler();
String page = httpClient.execute(httpGet, resHandler);

This can be used to grab the whole webpage as a string of html, i.e., "<html>...</html>"

Note You need to declare the following 'uses-permission' in the android manifest xml file... answer by @Squonk here

And also check this answer

How to change string into QString?

I came across this question because I had a problem when following the answers, so I post my solution here.

The above examples all show samples with strings containing only ASCII values, in which case everything works fine. However, when dealing with strings in Windows whcih can also contain other characters, like german umlauts, then these solutions don't work

The only code that gives correct results in such cases is

std::string s = "Übernahme";
QString q = QString::fromLocal8Bit(s.c_str());

If you don't have to deal with such strings, then the above answers will work fine.

Convert String to Float in Swift

you can use,

let wg = Float(wage.text!)

If you want to round the float to 2 decimal places:

let wg = Float(String(format: "%.2f",wage.text!)

Node.js: How to send headers with form data using request module?

Just remember set method to POST in options. Here is my code

var options = {
    url: 'http://www.example.com',
    method: 'POST', // Don't forget this line
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'X-MicrosoftAjax': 'Delta=true', // blah, blah, blah...
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.97 Safari/537.36',
    },
    form: {
        'key-1':'value-1',
        'key-2':'value-2',
        ...
    }
};

//console.log('options:', options);

// Create request to get data
request(options, (err, response, body) => {
    if (err) {
        //console.log(err);
    } else {
        console.log('body:', body);
    }
});

Find everything between two XML tags with RegEx

In our case, we receive an XML as a String and need to get rid of the values that have some "special" characters, like &<> etc. Basically someone can provide an XML to us in this form:

<notes>
  <note>
     <to>jenice & carl </to>
     <from>your neighbor <; </from>
  </note>
</notes>

So I need to find in that String the values jenice & carl and your neighbor <; and properly escape & and < (otherwise this is an invalid xml if you later pass it to an engine that shall rename unnamed).

Doing this with regex is a rather dumb idea to begin with, but it's cheap and easy. So the brave ones that would like to do the same thing I did, here you go:

    String xml = ...
    Pattern p = Pattern.compile("<(.+)>(?!\\R<)(.+)</(\\1)>");
    Matcher m = p.matcher(xml);
    String result = m.replaceAll(mr -> {
        if (mr.group(2).contains("&")) {
            return "<" + m.group(1) + ">" + m.group(2) + "+ some change" + "</" + m.group(3) + ">";
        }
        return "<" + m.group(1) + ">" + mr.group(2) + "</" + m.group(3) + ">";
    });

How do I make a column unique and index it in a Ruby on Rails migration?

If you have missed to add unique to DB column, just add this validation in model to check if the field is unique:

class Person < ActiveRecord::Base
  validates_uniqueness_of :user_name
end

refer here Above is for testing purpose only, please add index by changing DB column as suggested by @Nate

please refer this with index for more information

In Python, how do I iterate over a dictionary in sorted key order?

Haven't tested this very extensively, but works in Python 2.5.2.

>>> d = {"x":2, "h":15, "a":2222}
>>> it = iter(sorted(d.iteritems()))
>>> it.next()
('a', 2222)
>>> it.next()
('h', 15)
>>> it.next()
('x', 2)
>>>

If you are used to doing for key, value in d.iteritems(): ... instead of iterators, this will still work with the solution above

>>> d = {"x":2, "h":15, "a":2222}
>>> for key, value in sorted(d.iteritems()):
>>>     print(key, value)
('a', 2222)
('h', 15)
('x', 2)
>>>

With Python 3.x, use d.items() instead of d.iteritems() to return an iterator.

How do I put a variable inside a string?

In general, you can create strings using:

stringExample = "someString " + str(someNumber)
print(stringExample)
plot.savefig(stringExample)

Implementation difference between Aggregation and Composition in Java

Composition

final class Car {

  private final Engine engine;

  Car(EngineSpecs specs) {
    engine = new Engine(specs);
  }

  void move() {
    engine.work();
  }
}

Aggregation

final class Car {

  private Engine engine;

  void setEngine(Engine engine) {
    this.engine = engine;
  }

  void move() {
    if (engine != null)
      engine.work();
  }
}

In the case of composition, the Engine is completely encapsulated by the Car. There is no way for the outside world to get a reference to the Engine. The Engine lives and dies with the car. With aggregation, the Car also performs its functions through an Engine, but the Engine is not always an internal part of the Car. Engines may be swapped, or even completely removed. Not only that, but the outside world can still have a reference to the Engine, and tinker with it regardless of whether it's in the Car.

Can I stretch text using CSS?

Yes, you can actually with CSS 2D Transforms. This is supported in almost all modern browsers, including IE9+. Here's an example.

Actual HTML/CSS Stretch Example

HTML

<p>I feel like <span class="stretch">stretching</span>.</p>

CSS

span.stretch {
    display:inline-block;
    -webkit-transform:scale(2,1); /* Safari and Chrome */
    -moz-transform:scale(2,1); /* Firefox */
    -ms-transform:scale(2,1); /* IE 9 */
    -o-transform:scale(2,1); /* Opera */
    transform:scale(2,1); /* W3C */
}

TIP: You may need to add margin to your stretched text to prevent text collisions.

How to change the length of a column in a SQL Server table via T-SQL

So, let's say you have this table:

CREATE TABLE YourTable(Col1 VARCHAR(10))

And you want to change Col1 to VARCHAR(20). What you need to do is this:

ALTER TABLE YourTable
ALTER COLUMN Col1 VARCHAR(20)

That'll work without problems since the length of the column got bigger. If you wanted to change it to VARCHAR(5), then you'll first gonna need to make sure that there are not values with more chars on your column, otherwise that ALTER TABLE will fail.

Error: "setFile(null,false) call failed" when using log4j

Have a look at the error - 'log4j:ERROR setFile(null,false) call failed. java.io.FileNotFoundException: logs (Access is denied)'

It seems there's a log file named as 'logs' to which access is denied i.e it is not having sufficient permissions to write logs. Try by giving write permissions to the 'logs' log file. Hope it helps.

Python virtualenv questions

After creating virtual environment copy the activate.bat file from Script folder of python and paste to it your environment and open cmd from your virtual environment and run activate.bat file.enter image description here

Is there a way to make HTML5 video fullscreen?

HTML 5 video does go fullscreen in the latest nightly build of Safari, though I'm not sure how it is technically accomplished.

How to customize the back button on ActionBar

Changing back navigation icon differs for ActionBar and Toolbar.

For ActionBar override homeAsUpIndicator attribute:

<style name="CustomThemeActionBar" parent="android:Theme.Holo">
    <item name="homeAsUpIndicator">@drawable/ic_nav_back</item>
</style>

For Toolbar override navigationIcon attribute:

<style name="CustomThemeToolbar" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="navigationIcon">@drawable/ic_nav_back</item>
</style>

Fill an array with random numbers

If the randomness is controlled like this there can always generate any number of data points of a given range. If the random method in java is only used, we cannot guarantee that all the numbers will be unique.

_x000D_
_x000D_
package edu.iu.common;_x000D_
_x000D_
import java.util.ArrayList;_x000D_
import java.util.Random;_x000D_
_x000D_
public class RandomCentroidLocator {_x000D_
_x000D_
public static void main(String [] args){_x000D_
 _x000D_
 int min =0;_x000D_
 int max = 10;_x000D_
 int numCentroids = 10;_x000D_
 ArrayList<Integer> values = randomCentroids(min, max, numCentroids); _x000D_
 for(Integer i : values){_x000D_
  System.out.print(i+" ");_x000D_
 }_x000D_
 _x000D_
}_x000D_
_x000D_
private static boolean unique(ArrayList<Integer> arr, int num, int numCentroids) {_x000D_
_x000D_
 boolean status = true;_x000D_
 int count=0;_x000D_
 for(Integer i : arr){_x000D_
  if(i==num){_x000D_
   count++;_x000D_
  }_x000D_
 }_x000D_
 if(count==1){_x000D_
  status = true;_x000D_
 }else if(count>1){_x000D_
  status =false;_x000D_
 }_x000D_
 _x000D_
_x000D_
 return status;_x000D_
}_x000D_
_x000D_
// generate random centroid Ids -> these Ids can be used to retrieve data_x000D_
// from the data Points generated_x000D_
// simply we are picking up random items from the data points_x000D_
// in this case all the random numbers are unique_x000D_
// it provides the necessary number of unique and random centroids_x000D_
private static ArrayList<Integer> randomCentroids(int min, int max, int numCentroids) {_x000D_
_x000D_
 Random random = new Random();_x000D_
 ArrayList<Integer> values = new ArrayList<Integer>();_x000D_
 int num = -1;_x000D_
 int count = 0;_x000D_
 do {_x000D_
  num = random.nextInt(max - min + 1) + min;_x000D_
  values.add(num);_x000D_
  int index =values.size()-1;_x000D_
  if(unique(values, num, numCentroids)){    _x000D_
   count++;_x000D_
  }else{_x000D_
   values.remove(index);_x000D_
  }_x000D_
  _x000D_
 } while (!( count == numCentroids));_x000D_
_x000D_
 return values;_x000D_
_x000D_
}_x000D_
_x000D_
}
_x000D_
_x000D_
_x000D_

How to check if div element is empty

Using plain javascript

 var isEmpty = document.getElementById('cartContent').innerHTML === "";

And if you are using jquery it can be done like

 var isEmpty = $("#cartContent").html() === "";

Conditionally Remove Dataframe Rows with R

Subset is your safest and easiest answer.

subset(dataframe, A==B & E!=0)

Real data example with mtcars

subset(mtcars, cyl==6 & am!=0)

What's the difference between window.location and document.location in JavaScript?

Actually I notice a difference in chrome between both , For example if you want to do a navigation to a sandboxed frame from a child frame then you can do this just with document.location but not with window.location

How do you show animated GIFs on a Windows Form (c#)

It doesn't when you start a long operation behind, because everything STOPS since you'Re in the same thread.

How to execute a .bat file from a C# windows form app?

Here is what you are looking for:

Service hangs up at WaitForExit after calling batch file

It's about a question as to why a service can't execute a file, but it shows all the code necessary to do so.

proper hibernate annotation for byte[]

I have finally got this working. It expands on the solution from A. Garcia, however, since the problem lies in the hibernate type MaterializedBlob type just mapping Blob > bytea is not sufficient, we need a replacement for MaterializedBlobType which works with hibernates broken blob support. This implementation only works with bytea, but maybe the guy from the JIRA issue who wanted OID could contribute an OID implementation.

Sadly replacing these types at runtime is a pain, since they should be part of the Dialect. If only this JIRA enhanement gets into 3.6 it would be possible.

public class PostgresqlMateralizedBlobType extends AbstractSingleColumnStandardBasicType<byte[]> {
 public static final PostgresqlMateralizedBlobType INSTANCE = new PostgresqlMateralizedBlobType();

 public PostgresqlMateralizedBlobType() {
  super( PostgresqlBlobTypeDescriptor.INSTANCE, PrimitiveByteArrayTypeDescriptor.INSTANCE );
 }

  public String getName() {
   return "materialized_blob";
  }
}

Much of this could probably be static (does getBinder() really need a new instance?), but I don't really understand the hibernate internal so this is mostly copy + paste + modify.

public class PostgresqlBlobTypeDescriptor extends BlobTypeDescriptor implements SqlTypeDescriptor {
  public static final BlobTypeDescriptor INSTANCE = new PostgresqlBlobTypeDescriptor();

  public <X> ValueBinder<X> getBinder(final JavaTypeDescriptor<X> javaTypeDescriptor) {
   return new PostgresqlBlobBinder<X>(javaTypeDescriptor, this);
  }
  public <X> ValueExtractor<X> getExtractor(final JavaTypeDescriptor<X> javaTypeDescriptor) {
   return new BasicExtractor<X>( javaTypeDescriptor, this ) {
    protected X doExtract(ResultSet rs, String name, WrapperOptions options) throws SQLException { 
      return (X)rs.getBytes(name);
    }
   };
  }
}

public class PostgresqlBlobBinder<J> implements ValueBinder<J> {
 private final JavaTypeDescriptor<J> javaDescriptor;
 private final SqlTypeDescriptor sqlDescriptor;

 public PostgresqlBlobBinder(JavaTypeDescriptor<J> javaDescriptor, SqlTypeDescriptor sqlDescriptor) { 
  this.javaDescriptor = javaDescriptor; this.sqlDescriptor = sqlDescriptor;
 }  
 ...
 public final void bind(PreparedStatement st, J value, int index, WrapperOptions options) 
 throws SQLException {
  st.setBytes(index, (byte[])value);
 }
}

Pure CSS collapse/expand div

Depending on what browsers/devices you are looking to support, or what you are prepared to put up with for non-compliant browsers you may want to check out the <summary> and <detail> tags. They are for exactly this purpose. No css is required at all as the collapsing and showing are part of the tags definition/formatting.

I've made an example here:

<details>
<summary>This is what you want to show before expanding</summary>
<p>This is where you put the details that are shown once expanded</p>
</details>

Browser support varies. Try in webkit for best results. Other browsers may default to showing all the solutions. You can perhaps fallback to the hide/show method described above.

Text border using css (border around text)

I don't like that much solutions based on multiplying text-shadows, it's not really flexible, it may work for a 2 pixels stroke where directions to add are 8, but with just 3 pixels stroke directions became 16, and so on... Not really confortable to manage.

The right tool exists, it's SVG <text> The browsers' support problem worth nothing in this case, 'cause the usage of text-shadow has its own support problem too, filter: progid:DXImageTransform can be used or IE < 10 but often doesn't work as expected.

To me the best solution remains SVG with a fallback in not-stroked text for older browser:

This kind of approuch works on pratically all versions of Chrome and Firefox, Safari since version 3.04, Opera 8, IE 9

Compared to text-shadow whose supports are: Chrome 4.0, FF 3.5, IE 10, Safari 4.0, Opera 9, it results even more compatible.

_x000D_
_x000D_
.stroke {_x000D_
  margin: 0;_x000D_
  font-family: arial;_x000D_
  font-size:70px;_x000D_
  font-weight: bold;_x000D_
  }_x000D_
  _x000D_
  svg {_x000D_
    display: block;_x000D_
  }_x000D_
  _x000D_
  text {_x000D_
    fill: black;_x000D_
    stroke: red;_x000D_
    stroke-width: 3;_x000D_
  }
_x000D_
<p class="stroke">_x000D_
  <svg xmlns="http://www.w3.org/2000/svg" width="700" height="72" viewBox="0 0 700 72">_x000D_
    <text x="0" y="70">Stroked text</text>_x000D_
  </svg>_x000D_
</p>
_x000D_
_x000D_
_x000D_

How to get to Model or Viewbag Variables in a Script Tag

Use single quotation marks ('):

var val = '@ViewBag.ForSection';
alert(val);

PHP - count specific array values

Use the array_count_values function.

$countValues = array_count_values($myArray);

echo $countValues["Ben"];

What are the differences between .so and .dylib on osx?

The Mach-O object file format used by Mac OS X for executables and libraries distinguishes between shared libraries and dynamically loaded modules. Use otool -hv some_file to see the filetype of some_file.

Mach-O shared libraries have the file type MH_DYLIB and carry the extension .dylib. They can be linked against with the usual static linker flags, e.g. -lfoo for libfoo.dylib. They can be created by passing the -dynamiclib flag to the compiler. (-fPIC is the default and needn't be specified.)

Loadable modules are called "bundles" in Mach-O speak. They have the file type MH_BUNDLE. They can carry any extension; the extension .bundle is recommended by Apple, but most ported software uses .so for the sake of compatibility. Typically, you'll use bundles for plug-ins that extend an application; in such situations, the bundle will link against the application binary to gain access to the application’s exported API. They can be created by passing the -bundle flag to the compiler.

Both dylibs and bundles can be dynamically loaded using the dl APIs (e.g. dlopen, dlclose). It is not possible to link against bundles as if they were shared libraries. However, it is possible that a bundle is linked against real shared libraries; those will be loaded automatically when the bundle is loaded.

Historically, the differences were more significant. In Mac OS X 10.0, there was no way to dynamically load libraries. A set of dyld APIs (e.g. NSCreateObjectFileImageFromFile, NSLinkModule) were introduced with 10.1 to load and unload bundles, but they didn't work for dylibs. A dlopen compatibility library that worked with bundles was added in 10.3; in 10.4, dlopen was rewritten to be a native part of dyld and added support for loading (but not unloading) dylibs. Finally, 10.5 added support for using dlclose with dylibs and deprecated the dyld APIs.

On ELF systems like Linux, both use the same file format; any piece of shared code can be used as a library and for dynamic loading.

Finally, be aware that in Mac OS X, "bundle" can also refer to directories with a standardized structure that holds executable code and the resources used by that code. There is some conceptual overlap (particularly with "loadable bundles" like plugins, which generally contain executable code in the form of a Mach-O bundle), but they shouldn't be confused with Mach-O bundles discussed above.

Additional references:

How to read a file in reverse order?

def reverse_lines(filename):
    y=open(filename).readlines()
    return y[::-1]

SVN Error - Not a working copy

You must have deleted a SVN - base file from your project (which are read-only files). Due to this you get this error.

Check out a fresh project again, merge the changes (if any) of your older SVN project with new one using "Winmerge" and commit the changes in your latest check out.

Stop Visual Studio from launching a new browser window when starting debug?

You can right click on your project, then choose Properties , on Debug tab you should uncheck launch browser checkbox.

How to subtract 30 days from the current datetime in mysql?

MySQL subtract days from now:

select now(), now() - interval 1 day

Prints:

2014-10-08 09:00:56     2014-10-07 09:00:56

Other Interval Temporal Expression Unit arguments:

https://dev.mysql.com/doc/refman/5.5/en/expressions.html#temporal-intervals

select now() - interval 1 microsecond 
select now() - interval 1 second 
select now() - interval 1 minute 
select now() - interval 1 hour 
select now() - interval 1 day 
select now() - interval 1 week 
select now() - interval 1 month 
select now() - interval 1 year 

How to set Status Bar Style in Swift 3

Swift 4.0 Please use this code in "didFinishLaunchingWithOptions launchOptions:" Appdelegate class

UIApplication.shared.statusBarStyle = .lightContent
let statusBar: UIView = UIApplication.shared.value(forKey: "statusBar") as! UIView
if statusBar.responds(to: #selector(setter: UIView.backgroundColor)){
  statusBar.backgroundColor = UIColor.black
}

Get Excel sheet name and use as variable in macro

in a Visual Basic Macro you would use

pName = ActiveWorkbook.Path      ' the path of the currently active file
wbName = ActiveWorkbook.Name     ' the file name of the currently active file
shtName = ActiveSheet.Name       ' the name of the currently selected worksheet

The first sheet in a workbook can be referenced by

ActiveWorkbook.Worksheets(1)

so after deleting the [Report] tab you would use

ActiveWorkbook.Worksheets("Report").Delete
shtName = ActiveWorkbook.Worksheets(1).Name

to "work on that sheet later on" you can create a range object like

Dim MySheet as Range
MySheet = ActiveWorkbook.Worksheets(shtName).[A1]

and continue working on MySheet(rowNum, colNum) etc. ...

shortcut creation of a range object without defining shtName:

Dim MySheet as Range
MySheet = ActiveWorkbook.Worksheets(1).[A1]

Removing NA in dplyr pipe

I don't think desc takes an na.rm argument... I'm actually surprised it doesn't throw an error when you give it one. If you just want to remove NAs, use na.omit (base) or tidyr::drop_na:

outcome.df %>%
  na.omit() %>%
  group_by(Hospital, State) %>%
  arrange(desc(HeartAttackDeath)) %>%
  head()

library(tidyr)
outcome.df %>%
  drop_na() %>%
  group_by(Hospital, State) %>%
  arrange(desc(HeartAttackDeath)) %>%
  head()

If you only want to remove NAs from the HeartAttackDeath column, filter with is.na, or use tidyr::drop_na:

outcome.df %>%
  filter(!is.na(HeartAttackDeath)) %>%
  group_by(Hospital, State) %>%
  arrange(desc(HeartAttackDeath)) %>%
  head()

outcome.df %>%
  drop_na(HeartAttackDeath) %>%
  group_by(Hospital, State) %>%
  arrange(desc(HeartAttackDeath)) %>%
  head()

As pointed out at the dupe, complete.cases can also be used, but it's a bit trickier to put in a chain because it takes a data frame as an argument but returns an index vector. So you could use it like this:

outcome.df %>%
  filter(complete.cases(.)) %>%
  group_by(Hospital, State) %>%
  arrange(desc(HeartAttackDeath)) %>%
  head()

JavaScript TypeError: Cannot read property 'style' of null

Your missing a ' after night. right here getElementById('Night

Using isKindOfClass with Swift

Another approach using the new Swift 2 syntax is to use guard and nest it all in one conditional.

guard let touch = object.AnyObject() as? UITouch, let picker = touch.view as? UIPickerView else {
    return //Do Nothing
}
//Do something with picker

How do I create a view controller file after creating a new view controller?

To add new ViewController once you have have an existing ViewController, follow below step:

  1. Click on background of Main.storyboard.

  2. Search and select ViewController from object library at the utility window.

  3. Drag and drop it in background to create a new ViewController.

How to extract epoch from LocalDate and LocalDateTime?

The classes LocalDate and LocalDateTime do not contain information about the timezone or time offset, and seconds since epoch would be ambigious without this information. However, the objects have several methods to convert them into date/time objects with timezones by passing a ZoneId instance.

LocalDate

LocalDate date = ...;
ZoneId zoneId = ZoneId.systemDefault(); // or: ZoneId.of("Europe/Oslo");
long epoch = date.atStartOfDay(zoneId).toEpochSecond();

LocalDateTime

LocalDateTime time = ...;
ZoneId zoneId = ZoneId.systemDefault(); // or: ZoneId.of("Europe/Oslo");
long epoch = time.atZone(zoneId).toEpochSecond();

Importing the private-key/public-certificate pair in the Java KeyStore

A keystore needs a keystore file. The KeyStore class needs a FileInputStream. But if you supply null (instead of FileInputStream instance) an empty keystore will be loaded. Once you create a keystore, you can verify its integrity using keytool.

Following code creates an empty keystore with empty password

  KeyStore ks2 = KeyStore.getInstance("jks");
  ks2.load(null,"".toCharArray());
  FileOutputStream out = new FileOutputStream("C:\\mykeytore.keystore");
  ks2.store(out, "".toCharArray());

Once you have the keystore, importing certificate is very easy. Checkout this link for the sample code.

How to print a percentage value in python?

format supports a percentage floating point precision type:

>>> print "{0:.0%}".format(1./3)
33%

If you don't want integer division, you can import Python3's division from __future__:

>>> from __future__ import division
>>> 1 / 3
0.3333333333333333

# The above 33% example would could now be written without the explicit
# float conversion:
>>> print "{0:.0f}%".format(1/3 * 100)
33%

# Or even shorter using the format mini language:
>>> print "{:.0%}".format(1/3)
33%

What is the difference between Serialization and Marshaling?

My understanding of marshalling is different to the other answers.

Serialization:

To Produce or rehydrate a wire-format version of an object graph utilizing a convention.

Marshalling:

To Produce or rehydrate a wire-format version of an object graph by utilizing a mapping file, so that the results can be customized. The tool may start by adhering to a convention, but the important difference is the ability to customize results.

Contract First Development:

Marshalling is important within the context of contract first development.

  • Its possible to make changes to an internal object graph, while keeping the external interface stable over time. This way all of the service subscribers won't have to be modified for every trivial change.
  • Its possible to map the results across different languages. For example from the property name convention of one language ('property_name') to another ('propertyName').

How can I send large messages with Kafka (over 15MB)?

You need to adjust three (or four) properties:

  • Consumer side:fetch.message.max.bytes - this will determine the largest size of a message that can be fetched by the consumer.
  • Broker side: replica.fetch.max.bytes - this will allow for the replicas in the brokers to send messages within the cluster and make sure the messages are replicated correctly. If this is too small, then the message will never be replicated, and therefore, the consumer will never see the message because the message will never be committed (fully replicated).
  • Broker side: message.max.bytes - this is the largest size of the message that can be received by the broker from a producer.
  • Broker side (per topic): max.message.bytes - this is the largest size of the message the broker will allow to be appended to the topic. This size is validated pre-compression. (Defaults to broker's message.max.bytes.)

I found out the hard way about number 2 - you don't get ANY exceptions, messages, or warnings from Kafka, so be sure to consider this when you are sending large messages.

Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required

I have faced the same problem. It happens when you turn on 2 Step Verification (MFA). Just Turn off 2 Step Verification and your problem should be solved.

Cannot retrieve string(s) from preferences (settings)

All your exercise conditionals are separate and the else is only tied to the last if statement. Use else if to bind them all together in the way I believe you intend.

Converting JavaScript object with numeric keys into array

It's actually very straight forward with jQuery's $.map

var arr = $.map(obj, function(el) { return el });

FIDDLE

and almost as easy without jQuery as well, converting the keys to an array and then mapping back the values with Array.map

var arr = Object.keys(obj).map(function(k) { return obj[k] });

FIDDLE

That's assuming it's already parsed as a javascript object, and isn't actually JSON, which is a string format, in that case a run through JSON.parse would be necessary as well.

In ES2015 there's Object.values to the rescue, which makes this a breeze

var arr = Object.values(obj);

Powershell: count members of a AD group

If you cannot utilize the ActiveDirectory Module or the Get-ADGroupMember cmdlet, you can do it with the LDAP "in chain"-matching rule:

$GroupDN = "CN=MyGroup,OU=Groups,DC=mydomain,DC=tld"
$LDAPFilter = "(&(objectClass=user)(objectCategory=Person)(memberOf:1.2.840.113556.1.4.1941:=$GroupDN))"

# Ideally using an instance of adsisearcher here:
Get-ADObject -LDAPFilter $LDAPFilter

See MSDN for additional LDAP matching rules implemented in Active Directory

How to copy a java.util.List into another java.util.List

I was having the same problem ConcurrentAccessException and mysolution was to:

List<SomeBean> tempList = new ArrayList<>();

for (CartItem item : prodList) {
  tempList.add(item);
}
prodList.clear();
prodList = new ArrayList<>(tempList);

So it works only one operation at the time and avoids the Exeption...

jQuery set radio button

In my case, radio button value is fetched from database and then set into the form. Following code works for me.

$("input[name=name_of_radio_button_fields][value=" + saved_value_comes_from_database + "]").prop('checked', true);

bootstrap datepicker change date event doesnt fire up when manually editing dates or clearing date

I was using AngularJS and AngularStrap 2.3.7 and trying to catch the 'change' event by listening to a <form> element (not the input itself) and none of the answers here worked for me. I tried to do:

$(form).on('change change.dp dp.change changeDate' function () {...})

And nothing would fire. I ended up listening to the focus and blur events and setting a custom property before/after on the element itself:

// special hack to make bs-datepickers fire change events
// use timeout to make sure they all exist first
$timeout(function () {  
    $('input[bs-datepicker]').on('focus', function (e){
        e.currentTarget.focusValue = e.currentTarget.value;
    });        
    $('input[bs-datepicker]').on('blur', function (e){
        if (e.currentTarget.focusValue !== e.currentTarget.value) {
            var event = new Event('change', { bubbles: true });
            e.currentTarget.dispatchEvent(event);
        }
    });
})

This basically manually checks the value before and after the focus and blur and dispatches a new 'change' event. The { bubbles: true } bit is what got the form to detect the change. If you have any datepicker elements inside of an ng-if you'll need to wrap the listeners in a $timeout to make sure the digest happens first so all of your datepicker elements exist.

Hope this helps someone!

Getting value of HTML text input

Depends on where you want to use the email. If it's on the client side, without sending it to a PHP script, JQuery (or javascript) can do the trick.

I've created a fiddle to explain the same - http://jsfiddle.net/qHcpR/

It has an alert which goes off on load and when you click the textbox itself.

Best font for coding

I like Consolas a lot. This top-10 list is a good resource for others. It includes examples and descriptions.

How to create a custom string representation for a class object?

Just adding to all the fine answers, my version with decoration:

from __future__ import print_function
import six

def classrep(rep):
    def decorate(cls):
        class RepMetaclass(type):
            def __repr__(self):
                return rep

        class Decorated(six.with_metaclass(RepMetaclass, cls)):
            pass

        return Decorated
    return decorate


@classrep("Wahaha!")
class C(object):
    pass

print(C)

stdout:

Wahaha!

The down sides:

  1. You can't declare C without a super class (no class C:)
  2. C instances will be instances of some strange derivation, so it's probably a good idea to add a __repr__ for the instances as well.

Microsoft.ACE.OLEDB.12.0 provider is not registered

Basically, if you're on a 64-bit machine, IIS 7 is not (by default) serving 32-bit apps, which the database engine operates on. So here is exactly what you do:

1) ensure that the 2007 database engine is installed, this can be downloaded at: http://www.microsoft.com/downloads/details.aspx?FamilyID=7554F536-8C28-4598-9B72-EF94E038C891&displaylang=en

2) open IIS7 manager, and open the Application Pools area. On the right sidebar, you will see an option that says "Set application pool defaults". Click it, and a window will pop up with the options.

3) the second field down, which says 'Enable 32-bit applications' is probably set to FALSE by default. Simply click where it says 'false' to change it to 'true'.

4) Restart your app pool (you can do this by hitting RECYCLE instead of STOP then START, which will also work).

5) done, and your error message will go away.

Is there a simple, elegant way to define singletons?

A slightly different approach to implement the singleton in Python is the borg pattern by Alex Martelli (Google employee and Python genius).

class Borg:
    __shared_state = {}
    def __init__(self):
        self.__dict__ = self.__shared_state

So instead of forcing all instances to have the same identity, they share state.

Is there a way to get the git root directory in one command?

The man page for git-config (under Alias) says:

If the alias expansion is prefixed with an exclamation point, it will be treated as a shell command. [...] Note that shell commands will be executed from the top-level directory of a repository, which may not necessarily be the current directory.

So, on UNIX you can do:

git config --global --add alias.root '!pwd'

SVN commit command

To add a file/folder to the project, a good way is:

First of all add your files to /path/to/your/project/my/added/files, and then run following commands:

svn cleanup  /path/to/your/project

svn add --force /path/to/your/project/*

svn cleanup  /path/to/your/project

svn commit /path/to/your/project  -m 'Adding a file'

I used cleanup to prevent any segmentation fault (core dumped), and now the SVN project is updated.

Does Java read integers in little endian or big endian?

Use the network byte order (big endian), which is the same as Java uses anyway. See man htons for the different translators in C.

Java - Convert int to Byte Array of 4 Bytes?

This should work:

public static final byte[] intToByteArray(int value) {
    return new byte[] {
            (byte)(value >>> 24),
            (byte)(value >>> 16),
            (byte)(value >>> 8),
            (byte)value};
}

Code taken from here.

Edit An even simpler solution is given in this thread.

Convert array of strings into a string in Java

From Java 8, the simplest way I think is:

    String[] array = { "cat", "mouse" };
    String delimiter = "";
    String result = String.join(delimiter, array);

This way you can choose an arbitrary delimiter.

What was the strangest coding standard rule that you were forced to follow?

I absolutely hate it when someone doesn't use a naming convention. At where I worked, the lead developer (who I replaced) couldn't figure out if he wanted to use camelCase, or way_over_used_underscores. Personally, I hate the underscores and the camel case is easier to read, but it doesn't really matter as long as you keep to one standard.

PHP is especially bad at this, take a look at mysql_numrows which merges the two without the caps.

What is the correct JSON content type?

Not everything works for content type application/json.

If you are using Ext JS form submit to upload file, be aware that the server response is parsed by the browser to create the document for the <iframe>.

If the server is using JSON to send the return object, then the Content-Type header must be set to text/html in order to tell the browser to insert the text unchanged into the document body.

See the Ext JS 3.4.0 API documentation.

Spring Boot application.properties value not populating

This answer may or may not be applicable to your case ... Once I had a similar symptom and I double checked my code many times and all looked good but the @Value setting was still not taking effect. And then after doing File > Invalidate Cache / Restart with my IntelliJ (my IDE), the problem went away ...

This is very easy to try so may be worth a shot

Change drive in git bash for windows

How I do it in Windows 10

Go to your folder directory you want to open in git bash like so

enter image description here

After you have reached the folder simply type git bash in the top navigation area like so and hit enter.

enter image description here

A git bash for the destined folder will open for you.

enter image description here

Hope that helps.

@angular/material/index.d.ts' is not a module

And also ng update @angular/material will update your code and fix all imports

C++ - How to append a char to char*?

char ch = 't';
char chArray[2];
sprintf(chArray, "%c", ch);
char chOutput[10]="tes";
strcat(chOutput, chArray);
cout<<chOutput;

OUTPUT:

test

ReferenceError: document is not defined (in plain JavaScript)

This happened with me because I was using Next JS which has server side rendering. When you are using server side rendering there is no browser. Hence, there will not be any variable window or document. Hence this error shows up.

Work around :

If you are using Next JS you can use the dynamic rendering to prevent server side rendering for the component.

import dynamic from 'next/dynamic'

const DynamicComponentWithNoSSR = dynamic(() => import('../components/List'), {
  ssr: false
})

export default () => <DynamicComponentWithNoSSR />

If you are using any other server side rendering library. Then add the code that you want to run at the client side in componentDidMount. If you are using React Hooks then use useEffects in the place of componentsDidMount.

import React, {useState, useEffects} from 'react';

const DynamicComponentWithNoSSR = <>Some JSX</>

export default function App(){

[a,setA] = useState();
useEffect(() => {
    setA(<DynamicComponentWithNoSSR/>)
  });


return (<>{a}<>)
}

References :

  1. https://nextjs.org/docs/advanced-features/dynamic-import#with-no-ssr
  2. https://reactjs.org/docs/hooks-effect.html

How to use Git?

Using Git for version control

Visual studio code have Integrated Git Support.

  • Steps to use git.

Install Git : https://git-scm.com/downloads

1) Initialize your repository

Navigate to directory where you want to initialize Git

Use git init command This will create a empty .git repository

2) Stage the changes

Staging is process of making Git to track our newly added files. For example add a file and type git status. You will find the status that untracked file. So to stage the changes use git add filename. If now type git status, you will find that new file added for tracking.

You can also unstage files. Use git reset

3) Commit Changes

Commiting is the process of recording your changes to repository. To commit the statges changes, you need to add a comment that explains the changes you made since your previous commit.

Use git commit -m message string

We can also commit the multiple files of same type using command git add '*.txt'. This command will commit all files with txt extension.

4) Follow changes

The aim of using version control is to keep all versions of each and every file in our project, Compare the the current version with last commit and keep the log of all changes.

Use git log to see the log of all changes.

Visual studio code’s integrated git support help us to compare the code by double clicking on the file OR Use git diff HEAD

You can also undo file changes at the last commit. Use git checkout -- file_name

5) Create remote repositories

Till now we have created a local repository. But in order to push it to remote server. We need to add a remote repository in server.

Use git remote add origin server_git_url

Then push it to server repository

Use git push -u origin master

Let assume some time has passed. We have invited other people to our project who have pulled our changes, made their own commits, and pushed them.

So to get the changes from our team members, we need to pull the repository.

Use git pull origin master

6) Create Branches

Lets think that you are working on a feature or a bug. Better you can create a copy of your code(Branch) and make separate commits to. When you have done, merge this branch back to their master branch.

Use git branch branch_name

Now you have two local branches i.e master and XXX(new branch). You can switch branches using git checkout master OR git checkout new_branch_name

Commiting branch changes using git commit -m message

Switch back to master using git checkout master

Now we need to merge changes from new branch into our master Use git merge branch_name

Good! You just accomplished your bugfix Or feature development and merge. Now you don’t need the new branch anymore. So delete it using git branch -d branch_name

Now we are in the last step to push everything to remote repository using git push

Hope this will help you

How to insert double and float values to sqlite?

SQL Supports following types of affinities:

  • TEXT
  • NUMERIC
  • INTEGER
  • REAL
  • BLOB

If the declared type for a column contains any of these "REAL", "FLOAT", or "DOUBLE" then the column has 'REAL' affinity.

How to write log to file

This works for me

  1. created a package called logger.go

    package logger
    
    import (
      "flag"
      "os"
      "log"
      "go/build"
    )
    
    var (
      Log      *log.Logger
    )
    
    
    func init() {
        // set location of log file
        var logpath = build.Default.GOPATH + "/src/chat/logger/info.log"
    
       flag.Parse()
       var file, err1 = os.Create(logpath)
    
       if err1 != nil {
          panic(err1)
       }
          Log = log.New(file, "", log.LstdFlags|log.Lshortfile)
          Log.Println("LogFile : " + logpath)
    }
    
    1. import the package wherever you want to log e.g main.go

      package main
      
      import (
         "logger"
      )
      
      const (
         VERSION = "0.13"
       )
      
      func main() {
      
          // time to use our logger, print version, processID and number of running process
          logger.Log.Printf("Server v%s pid=%d started with processes: %d", VERSION, os.Getpid(),runtime.GOMAXPROCS(runtime.NumCPU()))
      
      }
      

Git ignore file for Xcode projects

gitignore.io: Create useful .gitignore files for your project

  • Example (macOS Objective-C Swift SwiftPackageManager Carthage)
  • Steps to use in Terminal (Refer to the YouTube Video)
    1. Create Git global config alias (One time only)

      git config --global alias.ignore '!gi() { curl -L -s https://www.gitignore.io/api/$@ ;}; gi'
      
    2. Enter the project directory

      cd <the project directory>
      
    3. Generate .gitignore file

      git ignore macOS,Objective-C,Swift,SwiftPackageManager,Carthage >.gitignore
      
    4. Add and commit .gitignore file

      git add .gitignore
      git commit -m "Add .gitignore file"
      

Is there any simple way to convert .xls file to .csv file? (Excel)

I integrate the @mattmc3 aswer. If you want to convert a xlsx file you should use this connection string (the string provided by matt works for xls formats, not xlsx):

var cnnStr = String.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=\"Excel 12.0;IMEX=1;HDR=NO\"", excelFilePath);

Is there a query language for JSON?

Check out https://github.com/niclasko/Cypher.js (note: I'm the author)

It's a zero-dependency Javascript implementation of the Cypher graph database query language along with a graph database. It runs in the browser (tested with Firefox, Chrome, IE).

With relevance to the question. It can be used to query JSON endpoints:

load json from "http://url/endpoint" as l return l limit 10

Here's an example of querying a complex JSON document and performing analysis on it:

Cypher.js JSON query example

Concatenate rows of two dataframes in pandas

Thanks to @EdChum I was struggling with same problem especially when indexes do not match. Unfortunatly in pandas guide this case is missed (when you for example delete some rows)

import pandas as pd
t=pd.DataFrame()
t['a']=[1,2,3,4]
t=t.loc[t['a']>1] #now index starts from 1

u=pd.DataFrame()
u['b']=[1,2,3] #index starts from 0

#option 1
#keep index of t
u.index = t.index 

#option 2
#index of t starts from 0
t.reset_index(drop=True, inplace=True)

#now concat will keep number of rows 
r=pd.concat([t,u], axis=1)

How can I remove text within parentheses with a regex?

For those who want to use Python, here's a simple routine that removes parenthesized substrings, including those with nested parentheses. Okay, it's not a regex, but it'll do the job!

def remove_nested_parens(input_str):
    """Returns a copy of 'input_str' with any parenthesized text removed. Nested parentheses are handled."""
    result = ''
    paren_level = 0
    for ch in input_str:
        if ch == '(':
            paren_level += 1
        elif (ch == ')') and paren_level:
            paren_level -= 1
        elif not paren_level:
            result += ch
    return result

remove_nested_parens('example_(extra(qualifier)_text)_test(more_parens).ext')

How do I decode a string with escaped unicode?

Note that the use of unescape() is deprecated and doesn't work with the TypeScript compiler, for example.

Based on radicand's answer and the comments section below, here's an updated solution:

var string = "http\\u00253A\\u00252F\\u00252Fexample.com";
decodeURIComponent(JSON.parse('"' + string.replace(/\"/g, '\\"') + '"'));

http://example.com

Random number from a range in a Bash Script

shuf -i 2000-65000 -n 1

Enjoy!

Edit: The range is inclusive.

Angular - ng: command not found

Try uninstalling the angular cli installed

npm uninstall -g angular-cli npm uninstall -g @angular/cli

The clean the node cache npm cache clean

Then npm install -g @angular/cli@latest

set Path the path C:\Users\admin\AppData\Roaming\npm\node_modules@angular\cli

Apache Spark: map vs mapPartitions?

Map :

  1. It processes one row at a time , very similar to map() method of MapReduce.
  2. You return from the transformation after every row.

MapPartitions

  1. It processes the complete partition in one go.
  2. You can return from the function only once after processing the whole partition.
  3. All intermediate results needs to be held in memory till you process the whole partition.
  4. Provides you like setup() map() and cleanup() function of MapReduce

Map Vs mapPartitions http://bytepadding.com/big-data/spark/spark-map-vs-mappartitions/

Spark Map http://bytepadding.com/big-data/spark/spark-map/

Spark mapPartitions http://bytepadding.com/big-data/spark/spark-mappartitions/

Uncaught TypeError: Cannot read property 'msie' of undefined - jQuery tools

As I don't plan to support old MS IE versions at all, I've simply replaced all references to browser.msie with false. Not a nice solution, I know, but it works for me.

(Actually, they appeared as !browser.msie, which could be omitted from the conditions.)

BigDecimal equals() versus compareTo()

You can also compare with double value

BigDecimal a= new BigDecimal("1.1"); BigDecimal b =new BigDecimal("1.1");
System.out.println(a.doubleValue()==b.doubleValue());

How to remove Firefox's dotted outline on BUTTONS as well as links?

Remove dotted outline from links, button and input element.

a:focus, a:active,
button::-moz-focus-inner,
input[type="reset"]::-moz-focus-inner,
input[type="button"]::-moz-focus-inner,
input[type="submit"]::-moz-focus-inner {
    border: 0;
    outline : 0;
}

Download data url file

If you also want to give a suggested name to the file (instead of the default 'download') you can use the following in Chrome, Firefox and some IE versions:

function downloadURI(uri, name) {
  var link = document.createElement("a");
  link.download = name;
  link.href = uri;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  delete link;
}

And the following example shows it's use:

downloadURI("data:text/html,HelloWorld!", "helloWorld.txt");

jQuery position DIV fixed at top on scroll

instead of doing it like that, why not just make the flyout position:fixed, top:0; left:0; once your window has scrolled pass a certain height:

jQuery

  $(window).scroll(function(){
      if ($(this).scrollTop() > 135) {
          $('#task_flyout').addClass('fixed');
      } else {
          $('#task_flyout').removeClass('fixed');
      }
  });

css

.fixed {position:fixed; top:0; left:0;}

Example

Unstage a deleted file in git

From manual page,

git-reset - Reset current HEAD to the specified state
git reset [-q] [<tree-ish>] [--] <paths>...
In the first and second form, copy entries from <tree-ish> to the index.

for example, when we use git reset HEAD~1 it reset our current HEAD to HEAD~1

so when we use git reset 'some-deleted-file-path'

git assume 'some-deleted-file-path' as some commit point and try to reset out current HEAD to there.

And it ends up fail

fatal: ambiguous argument 'some-deleted-file-path': unknown revision or path not in the working tree.

How is OAuth 2 different from OAuth 1?

Note there are serious security arguments against using Oauth 2:

one bleak article

and a more technical one

Note these are coming from Oauth 2's lead author.

Key points:

  • Oauth 2 offers no security on top of SSL while Oauth 1 is transport-independent.

  • in a sense SSL isn't secure in that the server does not verify the connection and the common client libraries make it easy to ignore failures.

    The problem with SSL/TLS, is that when you fail to verify the certificate on the client side, the connection still works. Any time ignoring an error leads to success, developers are going to do just that. The server has no way of enforcing certificate verification, and even if it could, an attacker will surely not.

  • you can fat-finger away all of your security, which is much harder to do in OAuth 1.0:

    The second common potential problem are typos. Would you consider it a proper design when omitting one character (the ‘s’ in ‘https’) voids the entire security of the token? Or perhaps sending the request (over a valid and verified SSL/TLS connection) to the wrong destination (say ‘http://gacebook.com’?). Remember, being able to use OAuth bearer tokens from the command line was clearly a use case bearer tokens advocates promoted.

Windows could not start the SQL Server (MSSQLSERVER) on Local Computer... (error code 3417)

In my particular case, I fixed this error by looking in the Event Viewer to get a clue as to the source of the issue:

enter image description here

I then followed the steps outlined at Rebuilding Master Database in SQL Server.

Note: Take some good backups first. After erasing the master database, you will have to attach to all of your existing databases again by browsing to the .mdf files.

In my particular case, the command to rebuild the master database was:

C:\Program Files\Microsoft SQL Server\110\Setup Bootstrap\SQLServer2012>setup /ACTION=rebuilddatabase /INSTANCENAME=MSSQLSERVER /SQLSYSADMINACCOUNTS=mike /sapwd=[insert password]

Note that this will reset SQL server to its defaults, so you will have to hope that you can restore the master database from E:\backup\master.bak. I couldn't find this file, so attached the existing databases (by browsing to the existing .mdf files), and everything was back to normal.

After fixing everything, I created a maintenance plan to back up everything, including the master database, on a weekly basis.

In my particular case, this whole issue was caused by a Seagate hard drive getting bad sectors a couple of months after its 2-year warranty period expired. Most of the Seagate drives I have ever owned have ended up expiring either before or shortly after warranty - so I'm avoiding Seagate like the plague now!!

HTTP error 403 in Python 3 Web Scraping

"This is probably because of mod_security or some similar server security feature which blocks known

spider/bot

user agents (urllib uses something like python urllib/3.3.0, it's easily detected)" - as already mentioned by Stefano Sanfilippo

from urllib.request import Request, urlopen
url="https://stackoverflow.com/search?q=html+error+403"
req = Request(url, headers={'User-Agent': 'Mozilla/5.0'})

web_byte = urlopen(req).read()

webpage = web_byte.decode('utf-8')

The web_byte is a byte object returned by the server and the content type present in webpage is mostly utf-8. Therefore you need to decode web_byte using decode method.

This solves complete problem while I was having trying to scrap from a website using PyCharm

P.S -> I use python 3.4

Simple regular expression for a decimal with a precision of 2

Won't you need to take the e in e666.76 into account?

With

(e|0-9)\d*\d.\d{1,2)

What is the role of "Flatten" in Keras?

Flatten make explicit how you serialize a multidimensional tensor (tipically the input one). This allows the mapping between the (flattened) input tensor and the first hidden layer. If the first hidden layer is "dense" each element of the (serialized) input tensor will be connected with each element of the hidden array. If you do not use Flatten, the way the input tensor is mapped onto the first hidden layer would be ambiguous.

how to return a char array from a function in C

Daniel is right: http://ideone.com/kgbo1C#view_edit_box

Change

test=substring(i,j,*s);

to

test=substring(i,j,s);  

Also, you need to forward declare substring:

char *substring(int i,int j,char *ch);

int main // ...

How to move git repository with all branches from bitbucket to github?

In case you want to move your local git repository to another upstream you can also do this:

to get the current remote url:

git remote get-url origin

will show something like: https://bitbucket.com/git/myrepo

to set new remote repository:

git remote set-url origin [email protected]:folder/myrepo.git

now push contents of current (develop) branch:

git push --set-upstream origin develop

You now have a full copy of the branch in the new remote.

optionally return to original git-remote for this local folder:

git remote set-url origin https://bitbucket.com/git/myrepo

Gives the benefit you can now get your new git-repository from github in another folder so that you have two local folders both pointing to the different remotes, the previous (bitbucket) and the new one both available.

How to execute a stored procedure inside a select query

You can create a temp table matching your proc output and insert into it.

CREATE TABLE #Temp (
    Col1 INT
)

INSERT INTO #Temp
    EXEC MyProc

Convert int to ASCII and back in Python

What about BASE58 encoding the URL? Like for example flickr does.

# note the missing lowercase L and the zero etc.
BASE58 = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ' 
url = ''
while node_id >= 58:
    div, mod = divmod(node_id, 58)
    url = BASE58[mod] + url
    node_id = int(div)

return 'http://short.com/%s' % BASE58[node_id] + url

Turning that back into a number isn't a big deal either.

How to read from stdin with fgets()?

You have a wrong idea of what fgets returns. Take a look at this: http://www.cplusplus.com/reference/clibrary/cstdio/fgets/

It returns null when it finds an EOF character. Try running the program above and pressing CTRL+D (or whatever combination is your EOF character), and the loop will exit succesfully.

How do you want to detect the end of the input? Newline? Dot (you said sentence xD)?

Leave only two decimal places after the dot

double doublVal = 123.45678;

There are two ways.

  1. for display in string:

    String.Format("{0:0.00}", doublVal );
    
  2. for geting again Double

    doublVal = Convert.ToDouble(String.Format("{0:0.00}", doublVal ));
    

JS: iterating over result of getElementsByClassName using Array.forEach

You can use Array.from to convert collection to array, which is way cleaner than Array.prototype.forEach.call:

Array.from(document.getElementsByClassName("myclass")).forEach(
    function(element, index, array) {
        // do stuff
    }
);

In older browsers which don't support Array.from, you need to use something like Babel.


ES6 also adds this syntax:

[...document.getElementsByClassName("myclass")].forEach(
    (element, index, array) => {
        // do stuff
    }
);

Rest destructuring with ... works on all array-like objects, not only arrays themselves, then good old array syntax is used to construct an array from the values.


While the alternative function querySelectorAll (which kinda makes getElementsByClassName obsolete) returns a collection which does have forEach natively, other methods like map or filter are missing, so this syntax is still useful:

[...document.querySelectorAll(".myclass")].map(
    (element, index, array) => {
        // do stuff
    }
);

[...document.querySelectorAll(".myclass")].map(element => element.innerHTML);

How to sort a data frame by alphabetic order of a character variable in R?

#sort dataframe by col
sort.df <- with(df,  df[order(sortbythiscolumn) , ])

#can also sort by more than one variable: sort by col1 and then by col2
sort2.df <- with(df, df[order(col1, col2) , ])

#sort in reverse order
sort2.df <- with(df, df[order(col1, -col2) , ])

Syntax for async arrow function

My async function

const getAllRedis = async (key) => {
  let obj = [];

  await client.hgetall(key, (err, object) => {
    console.log(object);
    _.map(object, (ob)=>{
      obj.push(JSON.parse(ob));
    })
    return obj;
    // res.send(obj);
});
}

What is better, adjacency lists or adjacency matrices for graph problems in C++?

It depends on what you're looking for.

With adjacency matrices you can answer fast to questions regarding if a specific edge between two vertices belongs to the graph, and you can also have quick insertions and deletions of edges. The downside is that you have to use excessive space, especially for graphs with many vertices, which is very inefficient especially if your graph is sparse.

On the other hand, with adjacency lists it is harder to check whether a given edge is in a graph, because you have to search through the appropriate list to find the edge, but they are more space efficient.

Generally though, adjacency lists are the right data structure for most applications of graphs.

What does API level mean?

An API is ready-made source code library.

In Java for example APIs are a set of related classes and interfaces that come in packages. This picture illustrates the libraries included in the Java Standard Edition API. Packages are denoted by their color.

This pictures illustrates the libraries included in the Java Standard Edition API

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 to get the Touch position in android?

@Override
    public boolean onTouch(View v, MotionEvent event) {
       float x = event.getX();
       float y = event.getY();
       return true;
    }

Fastest method of screen capturing on Windows

I wrote a video capture software, similar to FRAPS for DirectX applications. The source code is available and my article explains the general technique. Look at http://blog.nektra.com/main/2013/07/23/instrumenting-direct3d-applications-to-capture-video-and-calculate-frames-per-second/

Respect to your questions related to performance,

  • DirectX should be faster than GDI except when you are reading from the frontbuffer which is very slow. My approach is similar to FRAPS (reading from backbuffer). I intercept a set of methods from Direct3D interfaces.

  • For video recording in realtime (with minimal application impact), a fast codec is essential. FRAPS uses it's own lossless video codec. Lagarith and HUFFYUV are generic lossless video codecs designed for realtime applications. You should look at them if you want to output video files.

  • Another approach to recording screencasts could be to write a Mirror Driver. According to Wikipedia: When video mirroring is active, each time the system draws to the primary video device at a location inside the mirrored area, a copy of the draw operation is executed on the mirrored video device in real-time. See mirror drivers at MSDN: http://msdn.microsoft.com/en-us/library/windows/hardware/ff568315(v=vs.85).aspx.

Set background image in CSS using jquery

Try this

$("#globalsearchstr").focus(function(){
    $(this).parent().css("background", "url('../images/r-srchbg_white.png') no-repeat");
});

Why is this program erroneously rejected by three C++ compilers?

Draw the include below to make it compile:

#include <ChuckNorris>

I hear he can compile syntax errors...

Jenkins: Failed to connect to repository

Make sure that the RSA host key and the IP of the bitbucket server is added to the 'known hosts' file. The contents should look like

bitbucket.org,xx.xx.xx.xx ssh-rsa host_key

Remember to change ownership to Jenkins for all the files in /var/lib/jenkins/.ssh/

How to Execute stored procedure from SQL Plus?

You have two options, a PL/SQL block or SQL*Plus bind variables:

var z number

execute  my_stored_proc (-1,2,0.01,:z)

print z

How to get the focused element with jQuery?

Try this:

$(":focus").each(function() {
    alert("Focused Elem_id = "+ this.id );
});

jQuery Ajax Request inside Ajax Request

Here is an example:

$.ajax({
        type: "post",
        url: "ajax/example.php",
        data: 'page=' + btn_page,
        success: function (data) {
            var a = data; // This line shows error.
            $.ajax({
                type: "post",
                url: "example.php",
                data: 'page=' + a,
                success: function (data) {

                }
            });
        }
    });

Aligning two divs side-by-side

It's also possible to to do this without the wrapper - div#main. You can center the #page-wrap using the margin: 0 auto; method and then use the left:-n; method to position the #sidebar and adding the width of #page-wrap.

body { background: black; }
#sidebar    {
    position: absolute;
    left: 50%;
    width: 200px;
    height: 400px;
    background: red;
    margin-left: -230px;
    }

#page-wrap  {
    width: 60px;
    background: #fff;
    height: 400px;
    margin: 0 auto;
    }

However, the sidebar would disappear beyond the browser viewport if the window was smaller than the content.

Nick's second answer is best though, because it's also more maintainable as you don't have to adjust #sidebar if you want to resize #page-wrap.

Converting a string to int in Groovy

Several ways to achieve this. Examples are as below

a. return "22".toInteger()
b. if("22".isInteger()) return "22".toInteger()
c. return "22" as Integer()
d. return Integer.parseInt("22")

Hope this helps

Simplest way to set image as JPanel background

I am trying to set a JPanel's background using an image, however, every example I find seems to suggest extending the panel with its own class

yes you will have to extend JPanel and override the paintcomponent(Graphics g) function to do so.

@Override
  protected void paintComponent(Graphics g) {

    super.paintComponent(g);
        g.drawImage(bgImage, 0, 0, null);
}

I have been looking for a way to simply add the image without creating a whole new class and within the same method (trying to keep things organized and simple).

You can use other component which allows to add image as icon directly e.g. JLabel if you want.

ImageIcon icon = new ImageIcon(imgURL); 
JLabel thumb = new JLabel();
thumb.setIcon(icon);

But again in the bracket trying to keep things organized and simple !! what makes you to think that just creating a new class will lead you to a messy world ?

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

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

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

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

How do I select and store columns greater than a number in pandas?

Sample DF:

In [79]: df = pd.DataFrame(np.random.randint(5, 15, (10, 3)), columns=list('abc'))

In [80]: df
Out[80]:
    a   b   c
0   6  11  11
1  14   7   8
2  13   5  11
3  13   7  11
4  13   5   9
5   5  11   9
6   9   8   6
7   5  11  10
8   8  10  14
9   7  14  13

present only those rows where b > 10

In [81]: df[df.b > 10]
Out[81]:
   a   b   c
0  6  11  11
5  5  11   9
7  5  11  10
9  7  14  13

Minimums (for all columns) for the rows satisfying b > 10 condition

In [82]: df[df.b > 10].min()
Out[82]:
a     5
b    11
c     9
dtype: int32

Minimum (for the b column) for the rows satisfying b > 10 condition

In [84]: df.loc[df.b > 10, 'b'].min()
Out[84]: 11

UPDATE: starting from Pandas 0.20.1 the .ix indexer is deprecated, in favor of the more strict .iloc and .loc indexers.

Angular 4 Pipe Filter

Pipes in Angular 2+ are a great way to transform and format data right from your templates.

Pipes allow us to change data inside of a template; i.e. filtering, ordering, formatting dates, numbers, currencies, etc. A quick example is you can transfer a string to lowercase by applying a simple filter in the template code.

List of Built-in Pipes from API List Examples

{{ user.name | uppercase }}

Example of Angular version 4.4.7. ng version


Custom Pipes which accepts multiple arguments.

HTML « *ngFor="let student of students | jsonFilterBy:[searchText, 'name'] "
TS   « transform(json: any[], args: any[]) : any[] { ... }

Filtering the content using a Pipe « json-filter-by.pipe.ts

import { Pipe, PipeTransform, Injectable } from '@angular/core';

@Pipe({ name: 'jsonFilterBy' })
@Injectable()
export class JsonFilterByPipe implements PipeTransform {

  transform(json: any[], args: any[]) : any[] {
    var searchText = args[0];
    var jsonKey = args[1];

    // json = undefined, args = (2) [undefined, "name"]
    if(searchText == null || searchText == 'undefined') return json;
    if(jsonKey    == null || jsonKey    == 'undefined') return json;

    // Copy all objects of original array into new Array.
    var returnObjects = json;
    json.forEach( function ( filterObjectEntery ) {

      if( filterObjectEntery.hasOwnProperty( jsonKey ) ) {
        console.log('Search key is available in JSON object.');

        if ( typeof filterObjectEntery[jsonKey] != "undefined" && 
        filterObjectEntery[jsonKey].toLowerCase().indexOf(searchText.toLowerCase()) > -1 ) {
            // object value contains the user provided text.
        } else {
            // object didn't match a filter value so remove it from array via filter
            returnObjects = returnObjects.filter(obj => obj !== filterObjectEntery);
        }
      } else {
        console.log('Search key is not available in JSON object.');
      }

    })
    return returnObjects;
  }
}

Add to @NgModule « Add JsonFilterByPipe to your declarations list in your module; if you forget to do this you'll get an error no provider for jsonFilterBy. If you add to module then it is available to all the component's of that module.

@NgModule({
  imports: [
    CommonModule,
    RouterModule,
    FormsModule, ReactiveFormsModule,
  ],
  providers: [ StudentDetailsService ],
  declarations: [
    UsersComponent, UserComponent,

    JsonFilterByPipe,
  ],
  exports : [UsersComponent, UserComponent]
})
export class UsersModule {
    // ...
}

File Name: users.component.ts and StudentDetailsService is created from this link.

import { MyStudents } from './../../services/student/my-students';
import { Component, OnInit, OnDestroy } from '@angular/core';
import { StudentDetailsService } from '../../services/student/student-details.service';

@Component({
  selector: 'app-users',
  templateUrl: './users.component.html',
  styleUrls: [ './users.component.css' ],

  providers:[StudentDetailsService]
})
export class UsersComponent implements OnInit, OnDestroy  {

  students: MyStudents[];
  selectedStudent: MyStudents;

  constructor(private studentService: StudentDetailsService) { }

  ngOnInit(): void {
    this.loadAllUsers();
  }
  ngOnDestroy(): void {
    // ONDestroy to prevent memory leaks
  }

  loadAllUsers(): void {
    this.studentService.getStudentsList().then(students => this.students = students);
  }

  onSelect(student: MyStudents): void {
    this.selectedStudent = student;
  }

}

File Name: users.component.html

<div>
    <br />
    <div class="form-group">
        <div class="col-md-6" >
            Filter by Name: 
            <input type="text" [(ngModel)]="searchText" 
                   class="form-control" placeholder="Search By Category" />
        </div>
    </div>

    <h2>Present are Students</h2>
    <ul class="students">
    <li *ngFor="let student of students | jsonFilterBy:[searchText, 'name'] " >
        <a *ngIf="student" routerLink="/users/update/{{student.id}}">
            <span class="badge">{{student.id}}</span> {{student.name | uppercase}}
        </a>
    </li>
    </ul>
</div>

How do I print the elements of a C++ vector in GDB?

put the following in ~/.gdbinit

define print_vector
    if $argc == 2
        set $elem = $arg0.size()
        if $arg1 >= $arg0.size()
            printf "Error, %s.size() = %d, printing last element:\n", "$arg0", $arg0.size()
            set $elem = $arg1 -1
        end
        print *($arg0._M_impl._M_start + $elem)@1
    else
        print *($arg0._M_impl._M_start)@$arg0.size()
    end
end

document print_vector
Display vector contents
Usage: print_vector VECTOR_NAME INDEX
VECTOR_NAME is the name of the vector
INDEX is an optional argument specifying the element to display
end

After restarting gdb (or sourcing ~/.gdbinit), show the associated help like this

gdb) help print_vector
Display vector contents
Usage: print_vector VECTOR_NAME INDEX
VECTOR_NAME is the name of the vector
INDEX is an optional argument specifying the element to display

Example usage:

(gdb) print_vector videoconfig_.entries 0
$32 = {{subChannelId = 177 '\261', sourceId = 0 '\000', hasH264PayloadInfo = false, bitrate = 0,     payloadType = 68 'D', maxFs = 0, maxMbps = 0, maxFps = 134, encoder = 0 '\000', temporalLayers = 0 '\000'}}

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

dir has been mentioned, but that'll only give you the attributes' names. If you want their values as well try __dict__.

class O:
   def __init__ (self):
      self.value = 3

o = O()

Here is the output:

>>> o.__dict__

{'value': 3}

adb shell su works but adb root does not

I have a rooted Samsung Galaxy Trend Plus (GT-S7580).

Running 'adb root' gives me the same 'adbd cannot run as root in production builds' error.

For devices that have Developer Options -> Root access, choose "ADB only" to provide adb root access to the device (as suggested by NgaNguyenDuy).

Then try to run the command as per the solution at Launch a script as root through ADB. In my case, I just wanted to run the 'netcfg rndis0 dhcp' command, and I did it this way:

adb shell "su -c netcfg rndis0 dhcp"

Please check whether you are making any mistakes while running it this way.

If it still does not work, check whether you rooted the device correctly. If still no luck, try installing a custom ROM such as Cyanogen Mod in order for 'adb root' to work.

Java Inheritance - calling superclass method

Whenever you create child class object then that object has all the features of parent class. Here Super() is the facilty for accession parent.

If you write super() at that time parents's default constructor is called. same if you write super.

this keyword refers the current object same as super key word facilty for accessing parents.

Creating CSS Global Variables : Stylesheet theme management

You will either need LESS or SASS for the same..

But here is another alternative which I believe will work out in CSS3..

http://css3.bradshawenterprises.com/blog/css-variables/

Example :

 :root {
    -webkit-var-beautifulColor: rgba(255,40,100, 0.8);
    -moz-var-beautifulColor: rgba(255,40,100, 0.8);
    -ms-var-beautifulColor: rgba(255,40,100, 0.8);
    -o-var-beautifulColor: rgba(255,40,100, 0.8);
    var-beautifulColor: rgba(255,40,100, 0.8);
 }
  .example1 h1 {
    color: -webkit-var(beautifulColor);
    color: -moz-var(beautifulColor);
    color: -ms-var(beautifulColor);
    color: -o-var(beautifulColor);
    color: var(beautifulColor);
 }

How can I read and parse CSV files in C++?

I've got a way quicker solution, was originally intended for this question:

How to pull specific part of different strings?

But it was closed obviously. I'm not about to throw this away though:

#include <iostream>
#include <string>
#include <regex>

std::string text = "\"4,\"\"3\"\",\"\"Mon May 11 03:17:40 UTC 2009\"\",\"\"kindle2\"\",\"\"tpryan\"\",\"\"TEXT HERE\"\"\";;;;";

int main()
{
    std::regex r("(\".*\")(\".*\")(\".*\")(\".*\")(\".*\")(\".*\")(\".*\")(\".*\")(\".*\")(\".*\")");
    std::smatch m;
    std::regex_search(text, m, r);
    std::cout<<"FOUND: "<<m[9]<<std::endl;

    return 0;
}

Just pick out whichever match you want from the smatch collection by index. Regex is bliss.

What is the best way to access redux store outside a react component?

It might be a bit late but i think the best way is to use axios.interceptors as below. Import urls might change based on your project setup.

index.js

import axios from 'axios';
import setupAxios from './redux/setupAxios';
import store from './redux/store';

// some other codes

setupAxios(axios, store);

setupAxios.js

export default function setupAxios(axios, store) {
    axios.interceptors.request.use(
        (config) => {
            const {
                auth: { tokens: { authorization_token } },
            } = store.getState();

            if (authorization_token) {
                config.headers.Authorization = `Bearer ${authorization_token}`;
            }

            return config;
        },
       (err) => Promise.reject(err)
    );
}