Programs & Examples On #Bpython

bpython is a fancy interface to the Python interpreter for Unix-like operating systems.

json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 190)

I was parsing JSON from a REST API call and got this error. It turns out the API had become "fussier" (eg about order of parameters etc) and so was returning malformed results. Check that you are getting what you expect :)

Pandas create empty DataFrame with only column names

df.to_html() has a columns parameter.

Just pass the columns into the to_html() method.

df.to_html(columns=['A','B','C','D','E','F','G'])

How to update-alternatives to Python 3 without breaking apt?

Per Debian policy, python refers to Python 2 and python3 refers to Python 3. Don't try to change this system-wide or you are in for the sort of trouble you already discovered.

Virtual environments allow you to run an isolated Python installation with whatever version of Python and whatever libraries you need without messing with the system Python install.

With recent Python 3, venv is part of the standard library; with older versions, you might need to install python3-venv or a similar package.

$HOME~$ python --version
Python 2.7.11

$HOME~$ python3 -m venv myenv
... stuff happens ...

$HOME~$ . ./myenv/bin/activate

(myenv) $HOME~$ type python   # "type" is preferred over which; see POSIX
python is /home/you/myenv/bin/python

(myenv) $HOME~$ python --version
Python 3.5.1

A common practice is to have a separate environment for each project you work on, anyway; but if you want this to look like it's effectively system-wide for your own login, you could add the activation stanza to your .profile or similar.

Install pip in docker

Try this:

  1. Uncomment the following line in /etc/default/docker DOCKER_OPTS="--dns 8.8.8.8 --dns 8.8.4.4"
  2. Restart the Docker service sudo service docker restart
  3. Delete any images which have cached the invalid DNS settings.
  4. Build again and the problem should be solved.

From this question.

sys.path different in Jupyter and Python - how to import own modules in Jupyter?

Jupyter has its own PATH variable, JUPYTER_PATH.

Adding this line to the .bashrc file worked for me:

export JUPYTER_PATH=<directory_for_your_module>:$JUPYTER_PATH

How to fix symbol lookup error: undefined symbol errors in a cluster environment

After two dozens of comments to understand the situation, it was found that the libhdf5.so.7 was actually a symlink (with several levels of indirection) to a file that was not shared between the queued processes and the interactive processes. This means even though the symlink itself lies on a shared filesystem, the contents of the file do not and as a result the process was seeing different versions of the library.

For future reference: other than checking LD_LIBRARY_PATH, it's always a good idea to check a library with nm -D to see if the symbols actually exist. In this case it was found that they do exist in interactive mode but not when run in the queue. A quick md5sum revealed that the files were actually different.

Cmake is not able to find Python-libraries

Some last version of Ubuntu installs Python 3.4 by default and the CMake version from Ubuntu (2.8) only searches up to Python 3.3.

Try to add set(Python_ADDITIONAL_VERSIONS 3.4) before the find_package statement.

Remember to clean CMakeCache.txt too.

Python executable not finding libpython shared library

Putting on my gravedigger hat...

The best way I've found to address this is at compile time. Since you're the one setting prefix anyway might as well tell the executable explicitly where to find its shared libraries. Unlike OpenSSL and other software packages, Python doesn't give you nice configure directives to handle alternate library paths (not everyone is root you know...) In the simplest case all you need is the following:

./configure --enable-shared \
            --prefix=/usr/local \
            LDFLAGS="-Wl,--rpath=/usr/local/lib"

Or if you prefer the non-linux version:

./configure --enable-shared \
            --prefix=/usr/local \
            LDFLAGS="-R/usr/local/lib"

The "rpath" flag tells python it has runtime libraries it needs in that particular path. You can take this idea further to handle dependencies installed to a different location than the standard system locations. For example, on my systems since I don't have root access and need to make almost completely self-contained Python installs, my configure line looks like this:

./configure --enable-shared \
            --with-system-ffi \
            --with-system-expat \
            --enable-unicode=ucs4 \
            --prefix=/apps/python-${PYTHON_VERSION} \
            LDFLAGS="-L/apps/python-${PYTHON_VERSION}/extlib/lib -Wl,--rpath=/apps/python-${PYTHON_VERSION}/lib -Wl,--rpath=/apps/python-${PYTHON_VERSION}/extlib/lib" \
            CPPFLAGS="-I/apps/python-${PYTHON_VERSION}/extlib/include"

In this case I am compiling the libraries that python uses (like ffi, readline, etc) into an extlib directory within the python directory tree itself. This way I can tar the python-${PYTHON_VERSION} directory and land it anywhere and it will "work" (provided you don't run into libc or libm conflicts). This also helps when trying to run multiple versions of Python on the same box, as you don't need to keep changing your LD_LIBRARY_PATH or worry about picking up the wrong version of the Python library.

Edit: Forgot to mention, the compile will complain if you don't set the PYTHONPATH environment variable to what you use as your prefix and fail to compile some modules, e.g., to extend the above example, set the PYTHONPATH to the prefix used in the above example with export PYTHONPATH=/apps/python-${PYTHON_VERSION}...

Most Pythonic way to provide global configuration variables in config.py?

I like this solution for small applications:

class App:
  __conf = {
    "username": "",
    "password": "",
    "MYSQL_PORT": 3306,
    "MYSQL_DATABASE": 'mydb',
    "MYSQL_DATABASE_TABLES": ['tb_users', 'tb_groups']
  }
  __setters = ["username", "password"]

  @staticmethod
  def config(name):
    return App.__conf[name]

  @staticmethod
  def set(name, value):
    if name in App.__setters:
      App.__conf[name] = value
    else:
      raise NameError("Name not accepted in set() method")

And then usage is:

if __name__ == "__main__":
   # from config import App
   App.config("MYSQL_PORT")     # return 3306
   App.set("username", "hi")    # set new username value
   App.config("username")       # return "hi"
   App.set("MYSQL_PORT", "abc") # this raises NameError

.. you should like it because:

  • uses class variables (no object to pass around/ no singleton required),
  • uses encapsulated built-in types and looks like (is) a method call on App,
  • has control over individual config immutability, mutable globals are the worst kind of globals.
  • promotes conventional and well named access / readability in your source code
  • is a simple class but enforces structured access, an alternative is to use @property, but that requires more variable handling code per item and is object-based.
  • requires minimal changes to add new config items and set its mutability.

--Edit--: For large applications, storing values in a YAML (i.e. properties) file and reading that in as immutable data is a better approach (i.e. blubb/ohaal's answer). For small applications, this solution above is simpler.

How to give a pandas/matplotlib bar graph custom colors

For a more detailed answer on creating your own colormaps, I highly suggest visiting this page

If that answer is too much work, you can quickly make your own list of colors and pass them to the color parameter. All the colormaps are in the cm matplotlib module. Let's get a list of 30 RGB (plus alpha) color values from the reversed inferno colormap. To do so, first get the colormap and then pass it a sequence of values between 0 and 1. Here, we use np.linspace to create 30 equally-spaced values between .4 and .8 that represent that portion of the colormap.

from matplotlib import cm
color = cm.inferno_r(np.linspace(.4, .8, 30))
color

array([[ 0.865006,  0.316822,  0.226055,  1.      ],
       [ 0.851384,  0.30226 ,  0.239636,  1.      ],
       [ 0.832299,  0.283913,  0.257383,  1.      ],
       [ 0.817341,  0.270954,  0.27039 ,  1.      ],
       [ 0.796607,  0.254728,  0.287264,  1.      ],
       [ 0.775059,  0.239667,  0.303526,  1.      ],
       [ 0.758422,  0.229097,  0.315266,  1.      ],
       [ 0.735683,  0.215906,  0.330245,  1.      ],
       .....

Then we can use this to plot, using the data from the original post:

import random
x = [{i: random.randint(1, 5)} for i in range(30)]
df = pd.DataFrame(x)
df.plot(kind='bar', stacked=True, color=color, legend=False, figsize=(12, 4))

enter image description here

Replacing column values in a pandas DataFrame

I think that in answer should be pointed which type of object do you get in all methods suggested above: is it Series or DataFrame.

When you get column by w.female. or w[[2]] (where, suppose, 2 is number of your column) you'll get back DataFrame. So in this case you can use DataFrame methods like .replace.

When you use .loc or iloc you get back Series, and Series don't have .replace method, so you should use methods like apply, map and so on.

Wait until a process ends

I had a case where Process.HasExited didn't change after closing the window belonging to the process. So Process.WaitForExit() also didn't work. I had to monitor Process.Responding that went to false after closing the window like that:

while (!_process.HasExited && _process.Responding) {
  Thread.Sleep(100);
}
...

Perhaps this helps someone.

What is limiting the # of simultaneous connections my ASP.NET application can make to a web service?

Might it be possible that you're using a WCF-based web service reference? By default, the ServiceThrottlingBehavior.MaxConcurrentCalls is 16.

You could try updating your service reference behavior's <serviceThrottling> element

<serviceThrottling
    maxConcurrentCalls="999" 
    maxConcurrentSessions="999" 
    maxConcurrentInstances="999" />

(Note that I'd recommend the settings above.) See MSDN for more information how to configure an appropriate <behavior> element.

JQuery or JavaScript: How determine if shift key being pressed while clicking anchor tag hyperlink?

This works great for me:

function listenForShiftKey(e){
    var evt = e || window.event;
    if (evt.shiftKey) {
      shiftKeyDown = true;
    } else {
      shiftKeyDown = false;
    }
}

jQuery validate: How to add a rule for regular expression validation?

Thanks to the answer of redsquare I added a method like this:

$.validator.addMethod(
  "regex",
  function(value, element, regexp) {
    var re = new RegExp(regexp);
    return this.optional(element) || re.test(value);
  },
  "Please check your input."
);

Now all you need to do to validate against any regex is this:

$("#Textbox").rules("add", { regex: "^[a-zA-Z'.\\s]{1,40}$" })

Additionally, it looks like there is a file called additional-methods.js that contains the method "pattern", which can be a RegExp when created using the method without quotes.


Edit

The pattern function is now the preferred way to do this, making the example:

$("#Textbox").rules("add", { pattern: "^[a-zA-Z'.\\s]{1,40}$" })

How do I call an Angular 2 pipe with multiple arguments?

Since beta.16 the parameters are not passed as array to the transform() method anymore but instead as individual parameters:

{{ myData | date:'fullDate':'arg1':'arg2' }}


export class DatePipe implements PipeTransform {    
  transform(value:any, arg1:any, arg2:any):any {
        ...
}

https://github.com/angular/angular/blob/master/CHANGELOG.md#200-beta16-2016-04-26

pipes now take a variable number of arguments, and not an array that contains all arguments.

How to make audio autoplay on chrome

I've been banging away at this today, and I just wanted to add a little curiosum that I discovered to the discussion.

Anyway, I've gone off of this:

<iframe src="silence.mp3" allow="autoplay" id="audio" style="display:none"></iframe>
<audio id="audio" autoplay>
  <source src="helloworld.mp3">
</audio>

This:

<audio id="myAudio" src="helloworld.mp3"></audio>
<script type="text/javascript">
  document.getElementById("myAudio").play();
</script>

And finally this, a "solution" that is somewhat out of bounds if you'd rather just generate your own thing (which we do):

<script src='https://code.responsivevoice.org/responsivevoice.js'></script>
<input onclick='responsiveVoice.speak("Hello World");' type='button' value='Play' />

The discovery I've made and also the truly funny (strange? odd? ridiculous?) part is that in the case of the former two, you can actually beat the system by giving f5 a proper pounding; if you hit refresh repetetively very rapidly (some 5-10 times ought to do the trick), the audio will autoplay and then it will play a few times upon a sigle refresh only to return to it's evil ways. Fantastic!

In the announcement from Google it says that for media files to play "automatically", an interaction between the user and the site must have taken place. So the best "solution" that I've managed to come up with thus far is to add a button, rendering the playing of files less than automatic, but a lot more stable/reliable.

Footnotes for tables in LaTeX

If your table is already working with tabular, then easiest is to switch it to longtable, remembering to add

\usepackage{longtable}

For example:

\begin{longtable}{ll}
  2014--2015 & Something cool\footnote{first footnote} \\
  2016-- & Something cooler\footnote{second footnote}
\end{longtable}

A hex viewer / editor plugin for Notepad++?

Is a completely different (but still free) application an option? I use HxD, and it serves me better than the Notepad++ plugin. It can calculate hashes, open memory of a process, it is fast at opening files of any size, and it works exceptionally well with the clipboard.

I used to use the Notepad++ plugin, but not anymore.

Print empty line?

Python 2.x: Prints a newline

print      

Python 3.x: You must call the function

print() 

Source: https://docs.python.org/3.0/whatsnew/3.0.html

python: get directory two levels up

I have found that the following works well in 2.7.x

import os
two_up = os.path.normpath(os.path.join(__file__,'../'))

JavaScript: filter() for Objects

If you're willing to use underscore or lodash, you can use pick (or its opposite, omit).

Examples from underscore's docs:

_.pick({name: 'moe', age: 50, userid: 'moe1'}, 'name', 'age');
// {name: 'moe', age: 50}

Or with a callback (for lodash, use pickBy):

_.pick({name: 'moe', age: 50, userid: 'moe1'}, function(value, key, object) {
  return _.isNumber(value);
});
// {age: 50}

Drop columns whose name contains a specific string from pandas DataFrame

Don't drop. Catch the opposite of what you want.

df = df.filter(regex='^((?!badword).)*$').columns

Why use $_SERVER['PHP_SELF'] instead of ""

When you insert ANY variable into HTML, unless you want the browser to interpret the variable itself as HTML, it's best to use htmlspecialchars() on it. Among other things, it prevents hackers from inserting arbitrary HTML in your page.

The value of $_SERVER['PHP_SELF'] is taken directly from the URL entered in the browser. Therefore if you use it without htmlspecialchars(), you're allowing hackers to directly manipulate the output of your code.

For example, if I e-mail you a link to http://example.com/"><script>malicious_code_here()</script><span class=" and you have <form action="<?php echo $_SERVER['PHP_SELF'] ?>">, the output will be:

<form action="http://example.com/"><script>malicious_code_here()</script><span class="">

My script will run, and you will be none the wiser. If you were logged in, I may have stolen your cookies, or scraped confidential info from your page.

However, if you used <form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']) ?>">, the output would be:

<form action="http://example.com/&quot;&gt;&lt;script&gt;cookie_stealing_code()&lt;/script&gt;&lt;span class=&quot;">

When you submitted the form, you'd have a weird URL, but at least my evil script did not run.

On the other hand, if you used <form action="">, then the output would be the same no matter what I added to my link. This is the option I would recommend.

How can I list all collections in the MongoDB shell?

I use listCollections (supports MongoDB 3.0 and up) for this purpose.

Example:

db.runCommand({ listCollections: 1, filter: {}, nameOnly: true });

To fetch more information like the index of the collection:

db.runCommand({ listCollections: 1, filter: {}, nameOnly: false });

To print just the collection names:

db.runCommand({ listCollections: 1, filter: {}, nameOnly: true }).cursor.firstBatch.forEach(v => {print(v.name)})

I feel this provides more flexibility.

Read more: listCollections

How to clear a chart from a canvas so that hover events cannot be triggered?

I couldn't get .destroy() to work either so this is what I'm doing. The chart_parent div is where I want the canvas to show up. I need the canvas to resize each time, so this answer is an extension of the above one.

HTML:

<div class="main_section" > <div id="chart_parent"></div> <div id="legend"></div> </div>

JQuery:

  $('#chart').remove(); // this is my <canvas> element
  $('#chart_parent').append('<label for = "chart">Total<br /><canvas class="chart" id="chart" width='+$('#chart_parent').width()+'><canvas></label>');

How to list imported modules?

let say you've imported math and re:

>>import math,re

now to see the same use

>>print(dir())

If you run it before the import and after the import, one can see the difference.

Write / add data in JSON file using Node.js

Please try the following program. You might be expecting this output.

var fs = require('fs');

var data = {}
data.table = []
for (i=0; i <26 ; i++){
   var obj = {
       id: i,
       square: i * i
   }
   data.table.push(obj)
}
fs.writeFile ("input.json", JSON.stringify(data), function(err) {
    if (err) throw err;
    console.log('complete');
    }
);

Save this program in a javascript file, say, square.js.

Then run the program from command prompt using the command node square.js

What it does is, simply overwriting the existing file with new set of data, every time you execute the command.

Happy Coding.

Postgres - Transpose Rows to Columns

Use crosstab() from the tablefunc module.

SELECT * FROM crosstab(
   $$SELECT user_id, user_name, rn, email_address
     FROM  (
        SELECT u.user_id, u.user_name, e.email_address
             , row_number() OVER (PARTITION BY u.user_id
                            ORDER BY e.creation_date DESC NULLS LAST) AS rn
        FROM   usr u
        LEFT   JOIN email_tbl e USING (user_id)
        ) sub
     WHERE  rn < 4
     ORDER  BY user_id
   $$
  , 'VALUES (1),(2),(3)'
   ) AS t (user_id int, user_name text, email1 text, email2 text, email3 text);

I used dollar-quoting for the first parameter, which has no special meaning. It's just convenient if you have to escape single quotes in the query string which is a common case:

Detailed explanation and instructions here:

And in particular, for "extra columns":

The special difficulties here are:

  • The lack of key names.
    -> We substitute with row_number() in a subquery.

  • The varying number of emails.
    -> We limit to a max. of three in the outer SELECT
    and use crosstab() with two parameters, providing a list of possible keys.

Pay attention to NULLS LAST in the ORDER BY.

How do you hide the Address bar in Google Chrome for Chrome Apps?

2016-05-04-03:59A - Windows 7 - Google Chrome [Version 50.0.2661.94]

wanted this done for a 'YouTube Pop-out Player' without Chrome Address / Toolbar or Bookmarks Bar; solution ended up being a small edit of MarkHu's answer (because of new updates, i guess?)

Go to the page you want altered, select Chrome Toolbar's 'Hamburger button' (3 horizontal lines).

From there: More tools > Add to desktop... > Open as window (tick box) > Add (button).

... and, simply open your page from the new desktop shortcut, adjust as needed, and enjoy!

What causes this error? "Runtime error 380: Invalid property value"

One reason for this error is very silly mistake in code. If proper value is not passed to a property of ActiveX, then also this error is thrown.

Like empty value is passed to Font.Name property or text value is passed to Height property.

How can I rebuild indexes and update stats in MySQL innoDB?

For basic cleanup and re-analyzing you can run "OPTIMIZE TABLE ...", it will compact out the overhead in the indexes and run ANALYZE TABLE too, but it's not going to re-sort them and make them as small & efficient as they could be.

https://dev.mysql.com/doc/refman/8.0/en/optimize-table.html

However, if you want the indexes completely rebuilt for best performance, you can:

  1. drop / re-add indexes (obviously)
  2. dump / reload the table
  3. ALTER TABLE and "change" using the same storage engine
  4. REPAIR TABLE (only works for MyISAM, ARCHIVE, and CSV)

https://dev.mysql.com/doc/refman/8.0/en/rebuilding-tables.html

If you do an ALTER TABLE on a field (that is part of an index) and change its type, then it will also fully rebuild the related index(es).

Using local makefile for CLion instead of CMake

Newest version has better support literally for any generated Makefiles, through the compiledb

Three steps:

  1. install compiledb

    pip install compiledb
    
  2. run a dry make

    compiledb -n make 
    

    (do the autogen, configure if needed)

  3. there will be a compile_commands.json file generated open the project and you will see CLion will load info from the json file. If you your CLion still try to find CMakeLists.txt and cannot read compile_commands.json, try to remove the entire folder, re-download the source files, and redo step 1,2,3

Orignal post: Working with Makefiles in CLion using Compilation DB

In laymans terms, what does 'static' mean in Java?

In addition to what @inkedmn has pointed out, a static member is at the class level. Therefore, the said member is loaded into memory by the JVM once for that class (when the class is loaded). That is, there aren't n instances of a static member loaded for n instances of the class to which it belongs.

How to read/write files in .Net Core?

Works in Net Core 2.1

    var file = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot", "email", "EmailRegister.htm");

    string SendData = System.IO.File.ReadAllText(file);

How do you count the number of occurrences of a certain substring in a SQL varchar?

The Replace/Len test is cute, but probably very inefficient (especially in terms of memory). A simple function with a loop will do the job.

CREATE FUNCTION [dbo].[fn_Occurences] 
(
    @pattern varchar(255),
    @expression varchar(max)
)
RETURNS int
AS
BEGIN

    DECLARE @Result int = 0;

    DECLARE @index BigInt = 0
    DECLARE @patLen int = len(@pattern)

    SET @index = CHARINDEX(@pattern, @expression, @index)
    While @index > 0
    BEGIN
        SET @Result = @Result + 1;
        SET @index = CHARINDEX(@pattern, @expression, @index + @patLen)
    END

    RETURN @Result

END

How do I automatically play a Youtube video (IFrame API) muted?

Youtube don't provide muting through url parameter (see http://code.google.com/apis/youtube/player_parameters.html).

You have to use javascript for that. see http://code.google.com/apis/youtube/js_api_reference.html for details.

However, please note the warning on the page linked above: "The deprecation of the YouTube JavaScript Player API was announced on January 27, 2015. YouTube Flash embeds have also been deprecated. See the deprecation policy for more information. Please migrate your applications to the IFrame API, which can intelligently use whichever embedded player – HTML () or Flash () – the client supports."

Html

<iframe class="youtube-player" id="player" type="text/html" src="http://www.youtube.com/embed/JW5meKfy3fY?wmode=opaque&autohide=1&autoplay=1&enablejsapi=1" frameborder="0">&lt;br /&gt;</iframe>

please note enablejsapi=1 in the url.

Javascript

var player =  iframe.getElementById('player');
player.mute();

Update

Previous code had some issues and did not work with current API (playerVars syntax was wrong). Here is the updated code. You may need to tinker with the parameters you need.

_x000D_
_x000D_
         _x000D_
    <div id="player"></div>_x000D_
    <script>_x000D_
      // 1. This code loads the IFrame Player API code asynchronously._x000D_
      var tag = document.createElement('script');_x000D_
_x000D_
      tag.src = "https://www.youtube.com/iframe_api";_x000D_
      var firstScriptTag = document.getElementsByTagName('script')[0];_x000D_
      firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);_x000D_
_x000D_
      // 2. This function creates an <iframe> (and YouTube player)_x000D_
      //    after the API code downloads._x000D_
      var player;_x000D_
      function onYouTubeIframeAPIReady() {_x000D_
        player = new YT.Player('player', {_x000D_
          height: '100%',_x000D_
          width: '100%',_x000D_
          playerVars: {_x000D_
                    autoplay: 1,_x000D_
                    loop: 1,_x000D_
                    controls: 0,_x000D_
                    showinfo: 0,_x000D_
                    autohide: 1,_x000D_
                    modestbranding: 1,_x000D_
                    vq: 'hd1080'},_x000D_
          videoId: '1pzWROvY7gY',_x000D_
          events: {_x000D_
            'onReady': onPlayerReady,_x000D_
            'onStateChange': onPlayerStateChange_x000D_
          }_x000D_
        });_x000D_
      }_x000D_
_x000D_
      // 3. The API will call this function when the video player is ready._x000D_
      function onPlayerReady(event) {_x000D_
        event.target.playVideo();_x000D_
        player.mute();_x000D_
      }_x000D_
_x000D_
      var done = false;_x000D_
      function onPlayerStateChange(event) {_x000D_
        _x000D_
      }_x000D_
      function stopVideo() {_x000D_
        player.stopVideo();_x000D_
      }_x000D_
    </script>
_x000D_
_x000D_
_x000D_

How to write the code for the back button?

You need to tell the browser you are using javascript:

<a href="javascript:history.back(1)">Back</a> 

Also, your input element seems out of place in your code.

Jackson Vs. Gson

I did this research the last week and I ended up with the same 2 libraries. As I'm using Spring 3 (that adopts Jackson in its default Json view 'JacksonJsonView') it was more natural for me to do the same. The 2 lib are pretty much the same... at the end they simply map to a json file! :)

Anyway as you said Jackson has a + in performance and that's very important for me. The project is also quite active as you can see from their web page and that's a very good sign as well.

How do I drop table variables in SQL-Server? Should I even do this?

if somebody else comes across this... and you really need to drop it like while in a loop, you can just delete all from the table variable:

DELETE FROM @tableVariableName

Declare and initialize a Dictionary in Typescript

Edit: This has since been fixed in the latest TS versions. Quoting @Simon_Weaver's comment on the OP's post:

Note: this has since been fixed (not sure which exact TS version). I get these errors in VS, as you would expect: Index signatures are incompatible. Type '{ firstName: string; }' is not assignable to type 'IPerson'. Property 'lastName' is missing in type '{ firstName: string; }'.


Apparently this doesn't work when passing the initial data at declaration. I guess this is a bug in TypeScript, so you should raise one at the project site.

You can make use of the typed dictionary by splitting your example up in declaration and initialization, like:

var persons: { [id: string] : IPerson; } = {};
persons["p1"] = { firstName: "F1", lastName: "L1" };
persons["p2"] = { firstName: "F2" }; // will result in an error

How to parse a text file with C#

You could open the file up and use StreamReader.ReadLine to read the file in line-by-line. Then you can use String.Split to break each line into pieces (use a \t delimiter) to extract the second number.

As the number of items is different you would need to search the string for the pattern 'item\*.ddj'.

To delete an item you could (for example) keep all of the file's contents in memory and write out a new file when the user clicks 'Save'.

How to Join to first row

@Quassnoi answer is good, in some cases (especially if the outer table is big), a more efficient query might be with using windowed functions, like this:

SELECT  Orders.OrderNumber, LineItems2.Quantity, LineItems2.Description
FROM    Orders
LEFT JOIN 
        (
        SELECT  LineItems.Quantity, LineItems.Description, OrderId, ROW_NUMBER()
                OVER (PARTITION BY OrderId ORDER BY (SELECT NULL)) AS RowNum
        FROM    LineItems

        ) LineItems2 ON LineItems2.OrderId = Orders.OrderID And RowNum = 1

Sometimes you just need to test which query gives better performance.

How to check for an undefined or null variable in JavaScript?

whatever yyy is undefined or null, it will return true

if (typeof yyy == 'undefined' || !yyy) {
    console.log('yes');
} else {
    console.log('no');
}

yes

if (!(typeof yyy == 'undefined' || !yyy)) {
    console.log('yes');
} else {
    console.log('no');
}

no

How to expire a cookie in 30 minutes using jQuery?

I had issues getting the above code to work within cookie.js. The following code managed to create the correct timestamp for the cookie expiration in my instance.

var inFifteenMinutes = new Date(new Date().getTime() + 15 * 60 * 1000);

This was from the FAQs for Cookie.js

How to use componentWillMount() in React Hooks?

Ben Carp's answer seems like only valid one to me.

But since we are using functional ways just another approach can be benefiting from closure and HoC:

const InjectWillmount = function(Node, willMountCallback) {
  let isCalled = true;
  return function() {
    if (isCalled) {
      willMountCallback();
      isCalled = false;
    }
    return Node;
  };
};

Then use it :

const YourNewComponent = InjectWillmount(<YourComponent />, () => {
  console.log("your pre-mount logic here");
});

What is ToString("N0") format?

Here is a good start maybe

Double.ToString()

Have a look in the examples for a number of different formating options Double.ToString(string)

PuTTY scripting to log onto host

Figured this out with the help of a friend. The -m PuTTY option will end your session immediately after it executes the shell file. What I've done instead is I've created a batch script called putty.bat with these contents on my Windows machine:

@echo off
putty -load "host" -l username -pw password

This logs me in remotely to the Linux host. On the host side, I created a shell file called sql with these contents:

#!/bin/tcsh

add oracle10g
sqlplus username password

My host's Linux build used tcsh. Other Linux builds might use bash, so simply replace tcsh with bash and you should be fine.

To summarize, automating these steps are now done in two easy steps:

  1. Double-click putty.bat. This opens PuTTY and logs me into the host.
  2. Run command tcsh sql. This adds the oracle tool to my host, and logs me into the sql database.

HTTP URL Address Encoding in Java

Maybe can try UriUtils in org.springframework.web.util

UriUtils.encodeUri(input, "UTF-8")

Android Canvas.drawText

It should be noted that the documentation recommends using a Layout rather than Canvas.drawText directly. My full answer about using a StaticLayout is here, but I will provide a summary below.

String text = "This is some text.";

TextPaint textPaint = new TextPaint();
textPaint.setAntiAlias(true);
textPaint.setTextSize(16 * getResources().getDisplayMetrics().density);
textPaint.setColor(0xFF000000);

int width = (int) textPaint.measureText(text);
StaticLayout staticLayout = new StaticLayout(text, textPaint, (int) width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0, false);
staticLayout.draw(canvas);

Here is a fuller example in the context of a custom view:

enter image description here

public class MyView extends View {

    String mText = "This is some text.";
    TextPaint mTextPaint;
    StaticLayout mStaticLayout;

    // use this constructor if creating MyView programmatically
    public MyView(Context context) {
        super(context);
        initLabelView();
    }

    // this constructor is used when created from xml
    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initLabelView();
    }

    private void initLabelView() {
        mTextPaint = new TextPaint();
        mTextPaint.setAntiAlias(true);
        mTextPaint.setTextSize(16 * getResources().getDisplayMetrics().density);
        mTextPaint.setColor(0xFF000000);

        // default to a single line of text
        int width = (int) mTextPaint.measureText(mText);
        mStaticLayout = new StaticLayout(mText, mTextPaint, (int) width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0, false);

        // New API alternate
        //
        // StaticLayout.Builder builder = StaticLayout.Builder.obtain(mText, 0, mText.length(), mTextPaint, width)
        //        .setAlignment(Layout.Alignment.ALIGN_NORMAL)
        //        .setLineSpacing(1, 0) // multiplier, add
        //        .setIncludePad(false);
        // mStaticLayout = builder.build();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // Tell the parent layout how big this view would like to be
        // but still respect any requirements (measure specs) that are passed down.

        // determine the width
        int width;
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthRequirement = MeasureSpec.getSize(widthMeasureSpec);
        if (widthMode == MeasureSpec.EXACTLY) {
            width = widthRequirement;
        } else {
            width = mStaticLayout.getWidth() + getPaddingLeft() + getPaddingRight();
            if (widthMode == MeasureSpec.AT_MOST) {
                if (width > widthRequirement) {
                    width = widthRequirement;
                    // too long for a single line so relayout as multiline
                    mStaticLayout = new StaticLayout(mText, mTextPaint, width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0, false);
                }
            }
        }

        // determine the height
        int height;
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightRequirement = MeasureSpec.getSize(heightMeasureSpec);
        if (heightMode == MeasureSpec.EXACTLY) {
            height = heightRequirement;
        } else {
            height = mStaticLayout.getHeight() + getPaddingTop() + getPaddingBottom();
            if (heightMode == MeasureSpec.AT_MOST) {
                height = Math.min(height, heightRequirement);
            }
        }

        // Required call: set width and height
        setMeasuredDimension(width, height);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // do as little as possible inside onDraw to improve performance

        // draw the text on the canvas after adjusting for padding
        canvas.save();
        canvas.translate(getPaddingLeft(), getPaddingTop());
        mStaticLayout.draw(canvas);
        canvas.restore();
    }
}

How are Anonymous inner classes used in Java?

new Thread() {
        public void run() {
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                System.out.println("Exception message: " + e.getMessage());
                System.out.println("Exception cause: " + e.getCause());
            }
        }
    }.start();

This is also one of the example for anonymous inner type using thread

SQL select max(date) and corresponding value

Ah yes, that is how it is intended in SQL. You get the Max of every column seperately. It seems like you want to return values from the row with the max date, so you have to select the row with the max date. I prefer to do this with a subselect, as the queries keep compact easy to read.

SELECT TrainingID, CompletedDate, Notes
FROM HR_EmployeeTrainings ET 
WHERE (ET.AvantiRecID IS NULL OR ET.AvantiRecID = @avantiRecID) 
AND CompletedDate in 
   (Select Max(CompletedDate) from HR_EmployeeTrainings B
    where B.TrainingID = ET.TrainingID)

If you also want to match by AntiRecID you should include that in the subselect as well.

Check if DataRow exists by column name in c#?

if (row.Columns.Contains("US_OTHERFRIEND"))

Composer install error - requires ext_curl when it's actually enabled

According to https://github.com/composer/composer/issues/2119 you could extend your local composer.json to state that it provides the extension (which it doesn't really do - that's why you shouldn't publicly publish your package, only use it internally).

How to clear exisiting dropdownlist items when its content changes?

Using ddl.Items.Clear() will clear the dropdownlist however you must be sure that your dropdownlist is not set to:

AppendDataBoundItems="True"

This option will cause the rebound data to be appended to the existing list which will NOT be cleared prior to binding.

SOLUTION

Add AppendDataBoundItems="False" to your dropdownlist.

Now when data is rebound it will automatically clear all existing data beforehand.

Protected Sub ddl1_SelectedIndexChanged(sender As Object, e As EventArgs)
    ddl2.DataSource = sql2
    ddl2.DataBind()
End Sub

NOTE: This may not be suitable in all situations as appenddatbound items can cause your dropdown to append its own data on each change of the list.


TOP TIP

Still want a default list item adding to your dropdown but need to rebind data?

Use AppendDataBoundItems="False" to prevent duplication data on postback and then directly after binding your dropdownlist insert a new default list item.

ddl.Items.Insert(0, New ListItem("Select ...", ""))

Could not find com.android.tools.build:gradle:3.0.0-alpha1 in circle ci

Android Studio (Preview) sometimes recommends updating to a Gradle Plugin that is not available yet (did Google forget to publish it?). Such as today with

'com.android.tools.build:gradle:3.1.0-beta1'

I found I can see current versions of com.android.tools.build:gradle here, and then I just pick the newest:

https://dl.google.com/dl/android/maven2/index.html

I just found this beta1 gradle bug in the Android Bug Tracker. I also just learned Android Studio > Help Menu > Submit Feedback brought me to the bug tracker.

Found temporary solution at androiddev reddit for the 3.1.0-beta1 problem: Either roll back to Preview Canary 8, or switch to gradle plugin 3.0.1 until Canary 10 is released shortly.

Passing an array of data as an input parameter to an Oracle procedure

This is one way to do it:

SQL> set serveroutput on
SQL> CREATE OR REPLACE TYPE MyType AS VARRAY(200) OF VARCHAR2(50);
  2  /

Type created

SQL> CREATE OR REPLACE PROCEDURE testing (t_in MyType) IS
  2  BEGIN
  3    FOR i IN 1..t_in.count LOOP
  4      dbms_output.put_line(t_in(i));
  5    END LOOP;
  6  END;
  7  /

Procedure created

SQL> DECLARE
  2    v_t MyType;
  3  BEGIN
  4    v_t := MyType();
  5    v_t.EXTEND(10);
  6    v_t(1) := 'this is a test';
  7    v_t(2) := 'A second test line';
  8    testing(v_t);
  9  END;
 10  /

this is a test
A second test line

To expand on my comment to @dcp's answer, here's how you could implement the solution proposed there if you wanted to use an associative array:

SQL> CREATE OR REPLACE PACKAGE p IS
  2    TYPE p_type IS TABLE OF VARCHAR2(50) INDEX BY BINARY_INTEGER;
  3  
  4    PROCEDURE pp (inp p_type);
  5  END p;
  6  /

Package created
SQL> CREATE OR REPLACE PACKAGE BODY p IS
  2    PROCEDURE pp (inp p_type) IS
  3    BEGIN
  4      FOR i IN 1..inp.count LOOP
  5        dbms_output.put_line(inp(i));
  6      END LOOP;
  7    END pp;
  8  END p;
  9  /

Package body created
SQL> DECLARE
  2    v_t p.p_type;
  3  BEGIN
  4    v_t(1) := 'this is a test of p';
  5    v_t(2) := 'A second test line for p';
  6    p.pp(v_t);
  7  END;
  8  /

this is a test of p
A second test line for p

PL/SQL procedure successfully completed

SQL> 

This trades creating a standalone Oracle TYPE (which cannot be an associative array) with requiring the definition of a package that can be seen by all in order that the TYPE it defines there can be used by all.

How can I remove the decimal part from JavaScript number?

You can also use bitwise operators to truncate the decimal.

e.g.

var x = 9 / 2;
console.log(x); // 4.5

x = ~~x;
console.log(x); // 4

x = -3.7
console.log(~~x) // -3
console.log(x | 0) // -3
console.log(x << 0) // -3

Bitwise operations are considerably more efficient than the Math functions. The double not bitwise operator also seems to slightly outperform the x | 0 and x << 0 bitwise operations by a negligible amount.

// 952 milliseconds
for (var i = 0; i < 1000000; i++) {
    (i * 0.5) | 0;
}

// 1150 milliseconds
for (var i = 0; i < 1000000; i++) {
    (i * 0.5) << 0;
}

// 1284 milliseconds
for (var i = 0; i < 1000000; i++) {
    Math.trunc(i * 0.5);
}

// 939 milliseconds
for (var i = 0; i < 1000000; i++) {
    ~~(i * 0.5);
}

Also worth noting is that the bitwise not operator takes precedence over arithmetic operations, so you may need to surround calculations with parentheses to have the intended result:

x = -3.7

console.log(~~x * 2) // -6
console.log(x * 2 | 0) // -7
console.log(x * 2 << 0) // -7

console.log(~~(x * 2)) // -7
console.log(x * 2 | 0) // -7
console.log(x * 2 << 0) // -7

More info about the double bitwise not operator can be found at Double bitwise NOT (~~)

Make body have 100% of the browser height

Only with 1 line of CSS… You can get this done.

body{ height: 100vh; }

Comparing Dates in Oracle SQL

You can use trunc and to_date as follows:

select TO_CHAR (g.FECHA, 'DD-MM-YYYY HH24:MI:SS') fecha_salida, g.NUMERO_GUIA, g.BOD_ORIGEN, g.TIPO_GUIA, dg.DOC_NUMERO, dg.* 
from ils_det_guia dg, ils_guia g
where dg.NUMERO_GUIA = g.NUMERO_GUIA and dg.TIPO_GUIA = g.TIPO_GUIA and dg.BOD_ORIGEN = g.BOD_ORIGEN
and dg.LAB_CODIGO = 56 
and trunc(g.FECHA) > to_date('01/02/15','DD/MM/YY')
order by g.FECHA;

Is it possible to wait until all javascript files are loaded before executing javascript code?

You can use <script>'s defer attribute. It specifies that the script will be executed when the page has finished parsing.

<script defer src="path/to/yourscript.js">

A nice article about this: http://davidwalsh.name/script-defer

Browser support seems pretty good: http://caniuse.com/#search=defer

Another great article about loading JS using defer and async: https://flaviocopes.com/javascript-async-defer/

How to check if ping responded or not in a batch file

Simple version:

for /F "delims==, tokens=4" %a IN ('ping -n 2 127.0.0.1 ^| findstr /R "^Packets: Sent =.$"') DO (

if %a EQU 2 (
echo Success
) ELSE (
echo FAIL
)

)

But sometimes first ping just fail and second one work (or vice versa) right? So we want to get success when at least one ICMP reply has been returned successfully:

for /F "delims==, tokens=4" %a IN ('ping -n 2 192.168.1.1 ^| findstr /R "^Packets: Sent =.$"') DO (

if %a EQU 2 (
echo Success
) ELSE (
if %a EQU 1 (
echo Success
) ELSE (
echo FAIL
)
)

)

Brackets.io: Is there a way to auto indent / format <html>

The Identator plugin works to me in Brackets Release 1.13 versión 1.13.0-17696 (release 49d29a8bc) on S.O. Windows 10

Solving sslv3 alert handshake failure when trying to use a client certificate

The solution for me on a CentOS 8 system was checking the System Cryptography Policy by verifying the /etc/crypto-policies/config reads the default value of DEFAULT rather than any other value.

Once changing this value to DEFAULT, run the following command:

/usr/bin/update-crypto-policies --set DEFAULT

Rerun the curl command and it should work.

Oracle - Insert New Row with Auto Incremental ID

ELXAN@DB1> create table cedvel(id integer,ad varchar2(15));

Table created.

ELXAN@DB1> alter table cedvel add constraint pk_ad primary key(id);

Table altered.

ELXAN@DB1> create sequence test_seq start with 1 increment by 1;

Sequence created.

ELXAN@DB1> create or replace trigger ad_insert
before insert on cedvel
REFERENCING NEW AS NEW OLD AS OLD
for each row
begin
    select test_seq.nextval into :new.id from dual;
end;
/  2    3    4    5    6    7    8 

Trigger created.

ELXAN@DB1> insert into cedvel (ad) values ('nese');

1 row created.

How to use EOF to run through a text file in C?

I would suggest you to use fseek-ftell functions.

FILE *stream = fopen("example.txt", "r");

if(!stream) {
    puts("I/O error.\n");
    return;
}

fseek(stream, 0, SEEK_END);
long size = ftell(stream);
fseek(stream, 0, SEEK_SET);

while(1) {

    if(ftell(stream) == size) {
        break;
    }

    /* INSERT ROUTINE */

}

fclose(stream);

Reading input files by line using read command in shell scripting skips last line

One line answer:

IFS=$'\n'; for line in $(cat file.txt); do echo "$line" ; done

Sending email through Gmail SMTP server with C#

THE FOLLOWING WILL ALMOST CERTAINLY BE THE ANSWER TO YOUR QUESTION IF ALL ELSE HAS FAILED:

I got the exact same error, it turns out Google's new password strengh measuring algorithm has changed deeming my current password as too weak, and not telling me a thing about it (not even a message or warning)... How did I discover this? Well, I chose to change my password to see if it would help (tried everything else to no avail) and when I changed my password, it worked!

Then, for an experiment, I tried changing my password back to my previous password to see what would happen, and Gmail didn't actually allow me to do this, citing the reason "sorry we cannot allow you to save this change as your chosen password is too weak" and wouldn't let me go back to my old password. I figured from this that it was erroring out because either a) you need to change your password once every x amount of months or b). as I said before, their password strength algorithms changed and therefore the weak password i had was not accepted, even though they did not say anything about this when trying to login ANYWHERE! This (number 2) is the most likely scenario, as my weak password was about 4 months old, and it let me use it in Gmail.

It's pretty bad that they said nothing about this, but it makes sense. Because most hijacked emails are logged into using software outside of gmail, and I'm guessing you are required to have a stronger password if you want to use Gmail outside of the Gmail environment.

I hope this helps!

GUI-based or Web-based JSON editor that works like property explorer

Generally when I want to create a JSON or YAML string, I start out by building the Perl data structure, and then running a simple conversion on it. You could put a UI in front of the Perl data structure generation, e.g. a web form.

Converting a structure to JSON is very straightforward:

use strict;
use warnings;
use JSON::Any;

my $data = { arbitrary structure in here };
my $json_handler = JSON::Any->new(utf8=>1);
my $json_string = $json_handler->objToJson($data);

How to make a HTTP request using Ruby on Rails?

My favorite two ways to grab the contents of URLs are either OpenURI or Typhoeus.

OpenURI because it's everywhere, and Typhoeus because it's very flexible and powerful.

What causes: "Notice: Uninitialized string offset" to appear?

Check out the contents of your array with

echo '<pre>' . print_r( $arr, TRUE ) . '</pre>';

Pushing empty commits to remote

 $ git commit --allow-empty -m "Trigger Build"

How to convert int[] into List<Integer> in Java?

The smallest piece of code would be:

public List<Integer> myWork(int[] array) {
    return Arrays.asList(ArrayUtils.toObject(array));
}

where ArrayUtils comes from commons-lang :)

Firebase FCM force onTokenRefresh() to be called

Guys it has very simple solution

https://developers.google.com/instance-id/guides/android-implementation#generate_a_token

Note: If your app used tokens that were deleted by deleteInstanceID, your app will need to generate replacement tokens.

In stead of deleting instance Id, delete only token:

String authorizedEntity = PROJECT_ID;
String scope = "GCM";
InstanceID.getInstance(context).deleteToken(authorizedEntity,scope);

How to tell if UIViewController's view is visible

For over-full-screen or over-context modal presentation, "is visible" could mean it is on top of the view controller stack or just visible but covered by another view controller.

To check if the view controller "is the top view controller" is quite different from "is visible", you should check the view controller's navigation controller's view controller stack.

I wrote a piece of code to solve this problem:

extension UIViewController {
    public var isVisible: Bool {
        if isViewLoaded {
            return view.window != nil
        }
        return false
    }

    public var isTopViewController: Bool {
        if self.navigationController != nil {
            return self.navigationController?.visibleViewController === self
        } else if self.tabBarController != nil {
            return self.tabBarController?.selectedViewController == self && self.presentedViewController == nil
        } else {
            return self.presentedViewController == nil && self.isVisible
        }
    }
}

Inserting multiple rows in a single SQL query?

NOTE: This answer is for SQL Server 2005. For SQL Server 2008 and later, there are much better methods as seen in the other answers.

You can use INSERT with SELECT UNION ALL:

INSERT INTO MyTable  (FirstCol, SecondCol)
    SELECT  'First' ,1
    UNION ALL
SELECT  'Second' ,2
    UNION ALL
SELECT  'Third' ,3
...

Only for small datasets though, which should be fine for your 4 records.

Combine GET and POST request methods in Spring

Below is one of the way by which you can achieve that, may not be an ideal way to do.

Have one method accepting both types of request, then check what type of request you received, is it of type "GET" or "POST", once you come to know that, do respective actions and the call one method which does common task for both request Methods ie GET and POST.

@RequestMapping(value = "/books")
public ModelAndView listBooks(HttpServletRequest request){
     //handle both get and post request here
     // first check request type and do respective actions needed for get and post.

    if(GET REQUEST){

     //WORK RELATED TO GET

    }else if(POST REQUEST){

      //WORK RELATED TO POST

    }

    commonMethod(param1, param2....);
}

How do you check what version of SQL Server for a database using TSQL?

select substring(@@version,0,charindex(convert(varchar,SERVERPROPERTY('productversion')) ,@@version)+len(convert(varchar,SERVERPROPERTY('productversion')))) 

How do I analyze a .hprof file?

I personally prefer VisualVM. One of the features I like in VisualVM is heap dump comparison. When you are doing a heap dump analysis there are various ways to go about figuring out what caused the crash. One of the ways I have found useful is doing a comparison of healthy vs unhealthy heap dumps.

Following are the steps you can follow for it :

  1. Getting a heap dump of OutOfMemoryError let's call it "oome.hprof". You can get this via JVM parameter HeapDumpOnOutOfMemoryError.
  2. Restart the application let it run for a big (minutes/hours) depending on your application. Get another heap dump while the application is still running. Let's call it "healthy.hprof".
  3. You can open both these dumps in VisualVM and do a heap dump comparison. You can do it on class or package level. This can often point you into the direction of the issue.

link : https://visualvm.github.io

jquery live hover

jQuery 1.4.1 now supports "hover" for live() events, but only with one event handler function:

$("table tr").live("hover",

function () {

});

Alternatively, you can provide two functions, one for mouseenter and one for mouseleave:

$("table tr").live({
    mouseenter: function () {

    },
    mouseleave: function () {

    }
});

C: printf a float value

Try these to clarify the issue of right alignment in float point printing

printf(" 4|%4.1lf\n", 8.9);
printf("04|%04.1lf\n", 8.9);

the output is

 4| 8.9
04|08.9

Select the top N values by group

This seems more straightforward using data.table as it performs the sort while setting the key.

So, if I were to get the top 3 records in sort (ascending order), then,

require(data.table)
d <- data.table(mtcars, key="cyl")
d[, head(.SD, 3), by=cyl]

does it.

And if you want the descending order

d[, tail(.SD, 3), by=cyl] # Thanks @MatthewDowle

Edit: To sort out ties using mpg column:

d <- data.table(mtcars, key="cyl")
d.out <- d[, .SD[mpg %in% head(sort(unique(mpg)), 3)], by=cyl]

#     cyl  mpg  disp  hp drat    wt  qsec vs am gear carb rank
#  1:   4 22.8 108.0  93 3.85 2.320 18.61  1  1    4    1   11
#  2:   4 22.8 140.8  95 3.92 3.150 22.90  1  0    4    2    1
#  3:   4 21.5 120.1  97 3.70 2.465 20.01  1  0    3    1    8
#  4:   4 21.4 121.0 109 4.11 2.780 18.60  1  1    4    2    6
#  5:   6 18.1 225.0 105 2.76 3.460 20.22  1  0    3    1    7
#  6:   6 19.2 167.6 123 3.92 3.440 18.30  1  0    4    4    1
#  7:   6 17.8 167.6 123 3.92 3.440 18.90  1  0    4    4    2
#  8:   8 14.3 360.0 245 3.21 3.570 15.84  0  0    3    4    7
#  9:   8 10.4 472.0 205 2.93 5.250 17.98  0  0    3    4   14
# 10:   8 10.4 460.0 215 3.00 5.424 17.82  0  0    3    4    5
# 11:   8 13.3 350.0 245 3.73 3.840 15.41  0  0    3    4    3

# and for last N elements, of course it is straightforward
d.out <- d[, .SD[mpg %in% tail(sort(unique(mpg)), 3)], by=cyl]

HttpServletRequest to complete URL

Somewhat late to the party, but I included this in my MarkUtils-Web library in WebUtils - Checkstyle-approved and JUnit-tested:

import javax.servlet.http.HttpServletRequest;

public class GetRequestUrl{
    /**
     * <p>A faster replacement for {@link HttpServletRequest#getRequestURL()}
     *  (returns a {@link String} instead of a {@link StringBuffer} - and internally uses a {@link StringBuilder})
     *  that also includes the {@linkplain HttpServletRequest#getQueryString() query string}.</p>
     * <p><a href="https://gist.github.com/ziesemer/700376d8da8c60585438"
     *  >https://gist.github.com/ziesemer/700376d8da8c60585438</a></p>
     * @author Mark A. Ziesemer
     *  <a href="http://www.ziesemer.com.">&lt;www.ziesemer.com&gt;</a>
     */
    public String getRequestUrl(final HttpServletRequest req){
        final String scheme = req.getScheme();
        final int port = req.getServerPort();
        final StringBuilder url = new StringBuilder(256);
        url.append(scheme);
        url.append("://");
        url.append(req.getServerName());
        if(!(("http".equals(scheme) && (port == 0 || port == 80))
                || ("https".equals(scheme) && port == 443))){
            url.append(':');
            url.append(port);
        }
        url.append(req.getRequestURI());
        final String qs = req.getQueryString();
        if(qs != null){
            url.append('?');
            url.append(qs);
        }
        final String result = url.toString();
        return result;
    }
}

Probably the fastest and most robust answer here so far behind Mat Banik's - but even his doesn't account for potential non-standard port configurations with HTTP/HTTPS.

See also:

How to use ArrayList's get() method

To put it nice and simply, get(int index) returns the element at the specified index.

So say we had an ArrayList of Strings:

List<String> names = new ArrayList<String>();
names.add("Arthur Dent");
names.add("Marvin");
names.add("Trillian");
names.add("Ford Prefect");

Which can be visualised as: A visual representation of the array list Where 0, 1, 2, and 3 denote the indexes of the ArrayList.

Say we wanted to retrieve one of the names we would do the following: String name = names.get(1); Which returns the name at the index of 1.

Getting the element at index 1 So if we were to print out the name System.out.println(name); the output would be Marvin - Although he might not be too happy with us disturbing him.

How can I use Ruby to colorize the text output to a terminal?

You can use ANSI escape sequences to do this on the console. I know this works on Linux and OSX, I'm not sure if the Windows console (cmd) supports ANSI.

I did it in Java, but the ideas are the same.

//foreground color
public static final String BLACK_TEXT()   { return "\033[30m";}
public static final String RED_TEXT()     { return "\033[31m";}
public static final String GREEN_TEXT()   { return "\033[32m";}
public static final String BROWN_TEXT()   { return "\033[33m";}
public static final String BLUE_TEXT()    { return "\033[34m";}
public static final String MAGENTA_TEXT() { return "\033[35m";}
public static final String CYAN_TEXT()    { return "\033[36m";}
public static final String GRAY_TEXT()    { return "\033[37m";}

//background color
public static final String BLACK_BACK()   { return "\033[40m";}
public static final String RED_BACK()     { return "\033[41m";}
public static final String GREEN_BACK()   { return "\033[42m";}
public static final String BROWN_BACK()   { return "\033[43m";}
public static final String BLUE_BACK()    { return "\033[44m";}
public static final String MAGENTA_BACK() { return "\033[45m";}
public static final String CYAN_BACK()    { return "\033[46m";}
public static final String WHITE_BACK()   { return "\033[47m";}

//ANSI control chars
public static final String RESET_COLORS() { return "\033[0m";}
public static final String BOLD_ON()      { return "\033[1m";}
public static final String BLINK_ON()     { return "\033[5m";}
public static final String REVERSE_ON()   { return "\033[7m";}
public static final String BOLD_OFF()     { return "\033[22m";}
public static final String BLINK_OFF()    { return "\033[25m";}
public static final String REVERSE_OFF()  { return "\033[27m";}

How to access parameters in a RESTful POST method

Your @POST method should be accepting a JSON object instead of a string. Jersey uses JAXB to support marshaling and unmarshaling JSON objects (see the jersey docs for details). Create a class like:

@XmlRootElement
public class MyJaxBean {
    @XmlElement public String param1;
    @XmlElement public String param2;
}

Then your @POST method would look like the following:

@POST @Consumes("application/json")
@Path("/create")
public void create(final MyJaxBean input) {
    System.out.println("param1 = " + input.param1);
    System.out.println("param2 = " + input.param2);
}

This method expects to receive JSON object as the body of the HTTP POST. JAX-RS passes the content body of the HTTP message as an unannotated parameter -- input in this case. The actual message would look something like:

POST /create HTTP/1.1
Content-Type: application/json
Content-Length: 35
Host: www.example.com

{"param1":"hello","param2":"world"}

Using JSON in this way is quite common for obvious reasons. However, if you are generating or consuming it in something other than JavaScript, then you do have to be careful to properly escape the data. In JAX-RS, you would use a MessageBodyReader and MessageBodyWriter to implement this. I believe that Jersey already has implementations for the required types (e.g., Java primitives and JAXB wrapped classes) as well as for JSON. JAX-RS supports a number of other methods for passing data. These don't require the creation of a new class since the data is passed using simple argument passing.


HTML <FORM>

The parameters would be annotated using @FormParam:

@POST
@Path("/create")
public void create(@FormParam("param1") String param1,
                   @FormParam("param2") String param2) {
    ...
}

The browser will encode the form using "application/x-www-form-urlencoded". The JAX-RS runtime will take care of decoding the body and passing it to the method. Here's what you should see on the wire:

POST /create HTTP/1.1
Host: www.example.com
Content-Type: application/x-www-form-urlencoded;charset=UTF-8
Content-Length: 25

param1=hello&param2=world

The content is URL encoded in this case.

If you do not know the names of the FormParam's you can do the following:

@POST @Consumes("application/x-www-form-urlencoded")
@Path("/create")
public void create(final MultivaluedMap<String, String> formParams) {
    ...
}

HTTP Headers

You can using the @HeaderParam annotation if you want to pass parameters via HTTP headers:

@POST
@Path("/create")
public void create(@HeaderParam("param1") String param1,
                   @HeaderParam("param2") String param2) {
    ...
}

Here's what the HTTP message would look like. Note that this POST does not have a body.

POST /create HTTP/1.1
Content-Length: 0
Host: www.example.com
param1: hello
param2: world

I wouldn't use this method for generalized parameter passing. It is really handy if you need to access the value of a particular HTTP header though.


HTTP Query Parameters

This method is primarily used with HTTP GETs but it is equally applicable to POSTs. It uses the @QueryParam annotation.

@POST
@Path("/create")
public void create(@QueryParam("param1") String param1,
                   @QueryParam("param2") String param2) {
    ...
}

Like the previous technique, passing parameters via the query string does not require a message body. Here's the HTTP message:

POST /create?param1=hello&param2=world HTTP/1.1
Content-Length: 0
Host: www.example.com

You do have to be particularly careful to properly encode query parameters on the client side. Using query parameters can be problematic due to URL length restrictions enforced by some proxies as well as problems associated with encoding them.


HTTP Path Parameters

Path parameters are similar to query parameters except that they are embedded in the HTTP resource path. This method seems to be in favor today. There are impacts with respect to HTTP caching since the path is what really defines the HTTP resource. The code looks a little different than the others since the @Path annotation is modified and it uses @PathParam:

@POST
@Path("/create/{param1}/{param2}")
public void create(@PathParam("param1") String param1,
                   @PathParam("param2") String param2) {
    ...
}

The message is similar to the query parameter version except that the names of the parameters are not included anywhere in the message.

POST /create/hello/world HTTP/1.1
Content-Length: 0
Host: www.example.com

This method shares the same encoding woes that the query parameter version. Path segments are encoded differently so you do have to be careful there as well.


As you can see, there are pros and cons to each method. The choice is usually decided by your clients. If you are serving FORM-based HTML pages, then use @FormParam. If your clients are JavaScript+HTML5-based, then you will probably want to use JAXB-based serialization and JSON objects. The MessageBodyReader/Writer implementations should take care of the necessary escaping for you so that is one fewer thing that can go wrong. If your client is Java based but does not have a good XML processor (e.g., Android), then I would probably use FORM encoding since a content body is easier to generate and encode properly than URLs are. Hopefully this mini-wiki entry sheds some light on the various methods that JAX-RS supports.

Note: in the interest of full disclosure, I haven't actually used this feature of Jersey yet. We were tinkering with it since we have a number of JAXB+JAX-RS applications deployed and are moving into the mobile client space. JSON is a much better fit that XML on HTML5 or jQuery-based solutions.

Can I have two JavaScript onclick events in one element?

The HTML

<a href="#" id="btn">click</a>

And the javascript

// get a cross-browser function for adding events, place this in [global] or somewhere you can access it
var on = (function(){
    if (window.addEventListener) {
        return function(target, type, listener){
            target.addEventListener(type, listener, false);
        };
    }
    else {
        return function(object, sEvent, fpNotify){
            object.attachEvent("on" + sEvent, fpNotify);
        };
    }
}());

// find the element
var el = document.getElementById("btn");

// add the first listener
on(el, "click", function(){
    alert("foo");
});

// add the second listener
on(el, "click", function(){
    alert("bar");
});

This will alert both 'foo' and 'bar' when clicked.

Command-line svn for Windows?

cygwin is another option. It has a port of svn.

Matplotlib connect scatterplot points with line - Python

For red lines an points

plt.plot(dates, values, '.r-') 

or for x markers and blue lines

plt.plot(dates, values, 'xb-')

USB Debugging option greyed out

FYI My Motorola Xyboard had an "Off" icon at the top of developer options. Once I tapped that it worked.

Assign one struct to another in C

Yes if the structure is of the same type. Think it as a memory copy.

Get value of a merged cell of an excel from its cell address in vba

Even if it is really discouraged to use merge cells in Excel (use Center Across Selection for instance if needed), the cell that "contains" the value is the one on the top left (at least, that's a way to express it).

Hence, you can get the value of merged cells in range B4:B11 in several ways:

  • Range("B4").Value
  • Range("B4:B11").Cells(1).Value
  • Range("B4:B11").Cells(1,1).Value

You can also note that all the other cells have no value in them. While debugging, you can see that the value is empty.

Also note that Range("B4:B11").Value won't work (raises an execution error number 13 if you try to Debug.Print it) because it returns an array.

MySQL match() against() - order by relevance and column?

This might give the increased relevance to the head part that you want. It won't double it, but it might possibly good enough for your sake:

SELECT pages.*,
       MATCH (head, body) AGAINST ('some words') AS relevance,
       MATCH (head) AGAINST ('some words') AS title_relevance
FROM pages
WHERE MATCH (head, body) AGAINST ('some words')
ORDER BY title_relevance DESC, relevance DESC

-- alternatively:
ORDER BY title_relevance + relevance DESC

An alternative that you also want to investigate, if you've the flexibility to switch DB engine, is Postgres. It allows to set the weight of operators and to play around with the ranking.

Hashcode and Equals for Hashset

I think your questions will all be answered if you understand how Sets, and in particular HashSets work. A set is a collection of unique objects, with Java defining uniqueness in that it doesn't equal anything else (equals returns false).

The HashSet takes advantage of hashcodes to speed things up. It assumes that two objects that equal eachother will have the same hash code. However it does not assume that two objects with the same hash code mean they are equal. This is why when it detects a colliding hash code, it only compares with other objects (in your case one) in the set with the same hash code.

Just what is an IntPtr exactly?

What is a Pointer?

In all languages, a pointer is a type of variable that stores a memory address, and you can either ask them to tell you the address they are pointing at or the value at the address they are pointing at.

A pointer can be thought of as a sort-of book mark. Except, instead of being used to jump quickly to a page in a book, a pointer is used to keep track of or map blocks of memory.

Imagine your program's memory precisely like one big array of 65535 bytes.

Pointers point obediently

Pointers remember one memory address each, and therefore they each point to a single address in memory.

As a group, pointers remember and recall memory addresses, obeying your every command ad nauseum.

You are their king.

Pointers in C#

Specifically in C#, a pointer is an integer variable that stores a memory address between 0 and 65534.

Also specific to C#, pointers are of type int and therefore signed.

You can't use negatively numbered addresses though, neither can you access an address above 65534. Any attempt to do so will throw a System.AccessViolationException.

A pointer called MyPointer is declared like so:

int *MyPointer;

A pointer in C# is an int, but memory addresses in C# begin at 0 and extend as far as 65534.

Pointy things should be handled with extra special care

The word unsafe is intended to scare you, and for a very good reason: Pointers are pointy things, and pointy things e.g. swords, axes, pointers, etc. should be handled with extra special care.

Pointers give the programmer tight control of a system. Therefore mistakes made are likely to have more serious consequences.

In order to use pointers, unsafe code has to be enabled in your program's properties, and pointers have to be used exclusively in methods or blocks marked as unsafe.

Example of an unsafe block

unsafe
{
    // Place code carefully and responsibly here.

}

How to use Pointers

When variables or objects are declared or instantiated, they are stored in memory.

  • Declare a pointer by using the * symbol prefix.

int *MyPointer;

  • To get the address of a variable, you use the & symbol prefix.

MyPointer = &MyVariable;

Once an address is assigned to a pointer, the following applies:

  • Without * prefix to refer to the memory address being pointed to as an int.

MyPointer = &MyVariable; // Set MyPointer to point at MyVariable

  • With * prefix to get the value stored at the memory address being pointed to.

"MyPointer is pointing at " + *MyPointer;

Since a pointer is a variable that holds a memory address, this memory address can be stored in a pointer variable.

Example of pointers being used carefully and responsibly

    public unsafe void PointerTest()
    {
        int x = 100; // Create a variable named x

        int *MyPointer = &x; // Store the address of variable named x into the pointer named MyPointer

        textBox1.Text = ((int)MyPointer).ToString(); // Displays the memory address stored in pointer named MyPointer

        textBox2.Text = (*MyPointer).ToString(); // Displays the value of the variable named x via the pointer named MyPointer.

    }

Notice the type of the pointer is an int. This is because C# interprets memory addresses as integer numbers (int).

Why is it int instead of uint?

There is no good reason.

Why use pointers?

Pointers are a lot of fun. With so much of the computer being controlled by memory, pointers empower a programmer with more control of their program's memory.

Memory monitoring.

Use pointers to read blocks of memory and monitor how the values being pointed at change over time.

Change these values responsibly and keep track of how your changes affect your computer.

Difference between angle bracket < > and double quotes " " while including header files in C++?

It's compiler dependent. That said, in general using " prioritizes headers in the current working directory over system headers. <> usually is used for system headers. From to the specification (Section 6.10.2):

A preprocessing directive of the form

  # include <h-char-sequence> new-line

searches a sequence of implementation-defined places for a header identified uniquely by the specified sequence between the < and > delimiters, and causes the replacement of that directive by the entire contents of the header. How the places are specified or the header identified is implementation-defined.

A preprocessing directive of the form

  # include "q-char-sequence" new-line

causes the replacement of that directive by the entire contents of the source file identified by the specified sequence between the " delimiters. The named source file is searched for in an implementation-defined manner. If this search is not supported, or if the search fails, the directive is reprocessed as if it read

  # include <h-char-sequence> new-line

with the identical contained sequence (including > characters, if any) from the original directive.

So on most compilers, using the "" first checks your local directory, and if it doesn't find a match then moves on to check the system paths. Using <> starts the search with system headers.

Using multiple IF statements in a batch file

The explanation given by Merlyn above is pretty complete. However, I would like to elaborate on coding standards.

When several IF's are chained, the final command is executed when all the previous conditions are meet; this is equivalent to an AND operator. I used this behavior now and then, but I clearly indicate what I intend to do via an auxiliary Batch variable called AND:

SET AND=IF

IF EXIST somefile.txt %AND% EXIST someotherfile.txt SET var=somefile.txt,someotherfile.txt

Of course, this is NOT a true And operator and must not be used in combination with ELSE clause. This is just a programmer aid to increase the legibility of an instruction that is rarely used.

When I write Batch programs I always use several auxiliary variables that I designed with the sole purpose of write more readable code. For example:

SET AND=IF
SET THEN=(
SET ELSE=) ELSE (
SET NOELSE=
SET ENDIF=)
SET BEGIN=(
SET END=)
SET RETURN=EXIT /B

These variables aids in writting Batch programs in a much clearer way and helps to avoid subtle errors, as Merlyn suggested. For example:

IF EXIST "somefile.txt" %THEN%
  IF EXIST "someotherfile.txt" %THEN%
    SET var="somefile.txt,someotherfile.txt"
  %NOELSE%
  %ENDIF%
%NOELSE%
%ENDIF%

IF EXIST "%~1" %THEN%
  SET "result=%~1"
%ELSE%
  SET "result="
%ENDIF%

I even have variables that aids in writting WHILE-DO and REPEAT-UNTIL like constructs. This means that Batch variables may be used in some degree as preprocessor values.

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock'

I keep coming back to this post, I've encountered this error several times. It might have to do with importing all my databases after doing a fresh install.

I'm using homebrew. The only thing that used to fix it for me:

sudo mkdir /var/mysql
sudo ln -s /tmp/mysql.sock /var/mysql/mysql.sock

This morning, the issue returned after my machine decided to shut down overnight. The only thing that fixed it now was to upgrade mysql.

brew upgrade mysql

How can I build a recursive function in python?

Recursion in Python works just as recursion in an other language, with the recursive construct defined in terms of itself:

For example a recursive class could be a binary tree (or any tree):

class tree():
    def __init__(self):
        '''Initialise the tree'''
        self.Data = None
        self.Count = 0
        self.LeftSubtree = None
        self.RightSubtree = None

    def Insert(self, data):
        '''Add an item of data to the tree'''
        if self.Data == None:
            self.Data = data
            self.Count += 1
        elif data < self.Data:
            if self.LeftSubtree == None:
                # tree is a recurive class definition
                self.LeftSubtree = tree()
            # Insert is a recursive function
            self.LeftSubtree.Insert(data)
        elif data == self.Data:
            self.Count += 1
        elif data > self.Data:
            if self.RightSubtree == None:
                self.RightSubtree = tree()
            self.RightSubtree.Insert(data)

if __name__ == '__main__':
    T = tree()
    # The root node
    T.Insert('b')
    # Will be put into the left subtree
    T.Insert('a')
    # Will be put into the right subtree
    T.Insert('c')

As already mentioned a recursive structure must have a termination condition. In this class, it is not so obvious because it only recurses if new elements are added, and only does it a single time extra.

Also worth noting, python by default has a limit to the depth of recursion available, to avoid absorbing all of the computer's memory. On my computer this is 1000. I don't know if this changes depending on hardware, etc. To see yours :

import sys
sys.getrecursionlimit()

and to set it :

import sys #(if you haven't already)
sys.setrecursionlimit()

edit: I can't guarentee that my binary tree is the most efficient design ever. If anyone can improve it, I'd be happy to hear how

How do I measure execution time of a command on the Windows command line?

This is a comment/edit to Luke Sampson's nice timecmd.bat and reply to

For some reason this only gives me output in whole seconds... which for me is useless. I mean that I run timecmd pause, and it always results in 1.00 sec, 2.00 sec, 4.00 sec... even 0.00 sec! Windows 7. – Camilo Martin Sep 25 '13 at 16:00 "

On some configurations the delimiters may differ. The following change should cover atleast most western countries.

set options="tokens=1-4 delims=:,." (added comma)

The %time% milliseconds work on my system after adding that ','

(*because site doesn't allow anon comment and doesn't keep good track of identity even though I always use same guest email which combined with ipv6 ip and browser fingerprint should be enough to uniquely identify without password)

Connecting to Microsoft SQL server using Python

I Prefer this way ... it was much easier

http://www.pymssql.org/en/stable/pymssql_examples.html

conn = pymssql.connect("192.168.10.198", "odoo", "secret", "EFACTURA")
cursor = conn.cursor()
cursor.execute('SELECT * FROM usuario')

Multi-Column Join in Hibernate/JPA Annotations

If this doesn't work I'm out of ideas. This way you get the 4 columns in both tables (as Bar owns them and Foo uses them to reference Bar) and the generated IDs in both entities. The set of 4 columns has to be unique in Bar so the many-to-one relation doesn't become a many-to-many.

@Embeddable
public class AnEmbeddedObject
{
    @Column(name = "column_1")
    private Long column1;
    @Column(name = "column_2")
    private Long column2;
    @Column(name = "column_3")
    private Long column3;
    @Column(name = "column_4")
    private Long column4;
}

@Entity
public class Foo
{
    @Id
    @Column(name = "id")
    @GeneratedValue(generator = "seqGen")
    @SequenceGenerator(name = "seqGen", sequenceName = "FOO_ID_SEQ", allocationSize = 1)
    private Long id;
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumns({
        @JoinColumn(name = "column_1", referencedColumnName = "column_1"),
        @JoinColumn(name = "column_2", referencedColumnName = "column_2"),
        @JoinColumn(name = "column_3", referencedColumnName = "column_3"),
        @JoinColumn(name = "column_4", referencedColumnName = "column_4")
    })
    private Bar bar;
}

@Entity
@Table(uniqueConstraints = @UniqueConstraint(columnNames = {
    "column_1",
    "column_2",
    "column_3",
    "column_4"
}))
public class Bar
{
    @Id
    @Column(name = "id")
    @GeneratedValue(generator = "seqGen")
    @SequenceGenerator(name = "seqGen", sequenceName = "BAR_ID_SEQ", allocationSize = 1)
    private Long id;
    @Embedded
    private AnEmbeddedObject anEmbeddedObject;
}

How to enable DataGridView sorting when user clicks on the column header?

put this line in your windows form (on load or better in a public method like "binddata" ):

//
// bind the data and make the grid sortable 
//
this.datagridview1.MakeSortable( myenumerablecollection ); 

Put this code in a file called DataGridViewExtensions.cs (or similar)

// MakeSortable extension. 
// this will make any enumerable collection sortable on a datagrid view.  

//
// BEGIN MAKESORTABLE - Mark A. Lloyd
//
// Enables sort on all cols of a DatagridView 

//



    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Threading.Tasks;
    using System.Windows.Forms;

    public static class DataGridViewExtensions
    {
    public static void MakeSortable<T>(
        this DataGridView dataGridView, 
        IEnumerable<T> dataSource,
        SortOrder defaultSort = SortOrder.Ascending, 
        SortOrder initialSort = SortOrder.None)
    {
        var sortProviderDictionary = new Dictionary<int, Func<SortOrder, IEnumerable<T>>>();
        var previousSortOrderDictionary = new Dictionary<int, SortOrder>();
        var itemType = typeof(T);
        dataGridView.DataSource = dataSource;
        foreach (DataGridViewColumn c in dataGridView.Columns)
        {
            object Provider(T info) => itemType.GetProperty(c.Name)?.GetValue(info);
            sortProviderDictionary[c.Index] = so => so != defaultSort ? 
                dataSource.OrderByDescending<T, object>(Provider) : 
                dataSource.OrderBy<T,object>(Provider);
            previousSortOrderDictionary[c.Index] = initialSort;
        }

        async Task DoSort(int index)
        {

            switch (previousSortOrderDictionary[index])
            {
                case SortOrder.Ascending:
                    previousSortOrderDictionary[index] = SortOrder.Descending;
                    break;
                case SortOrder.None:
                case SortOrder.Descending:
                    previousSortOrderDictionary[index] = SortOrder.Ascending;
                    break;
                default:
                    throw new ArgumentOutOfRangeException();
            }

            IEnumerable<T> sorted = null;
            dataGridView.Cursor = Cursors.WaitCursor;
            dataGridView.Enabled = false;
            await Task.Run(() => sorted = sortProviderDictionary[index](previousSortOrderDictionary[index]).ToList());
            dataGridView.DataSource = sorted;
            dataGridView.Enabled = true;
            dataGridView.Cursor = Cursors.Default;

        }

        dataGridView.ColumnHeaderMouseClick+= (object sender, DataGridViewCellMouseEventArgs e) => DoSort(index: e.ColumnIndex);
    }
}

Returning data from Axios API

    async handleResponse(){
      const result = await this.axiosTest();
    }

    async axiosTest () {
    return await axios.get(url)
    .then(function (response) {
            console.log(response.data);
            return response.data;})
.catch(function (error) {
    console.log(error);
});
}

You can find check https://flaviocopes.com/axios/#post-requests url and find some relevant information in the GET section of this post.

How to output to the console in C++/Windows

If you're using Visual Studio, it should work just fine!

Here's a code example:

#include <iostream>

using namespace std;

int main (int) {
    cout << "This will print to the console!" << endl;
}

Make sure you chose a Win32 console application when creating a new project. Still you can redirect the output of your project to a file by using the console switch (>>). This will actually redirect the console pipe away from the stdout to your file. (for example, myprog.exe >> myfile.txt).

I wish I'm not mistaken!

Webpack how to build production code and how to use it

This will help you.

plugins: [
    new webpack.DefinePlugin({
      'process.env': {
        // This has effect on the react lib size
        'NODE_ENV': JSON.stringify('production'),
      }
    }),
    new ExtractTextPlugin("bundle.css", {allChunks: false}),
    new webpack.optimize.AggressiveMergingPlugin(),
    new webpack.optimize.OccurrenceOrderPlugin(),
    new webpack.optimize.DedupePlugin(),
    new webpack.optimize.UglifyJsPlugin({
      mangle: true,
      compress: {
        warnings: false, // Suppress uglification warnings
        pure_getters: true,
        unsafe: true,
        unsafe_comps: true,
        screw_ie8: true
      },
      output: {
        comments: false,
      },
      exclude: [/\.min\.js$/gi] // skip pre-minified libs
    }),
    new webpack.IgnorePlugin(/^\.\/locale$/, [/moment$/]), //https://stackoverflow.com/questions/25384360/how-to-prevent-moment-js-from-loading-locales-with-webpack
    new CompressionPlugin({
      asset: "[path].gz[query]",
      algorithm: "gzip",
      test: /\.js$|\.css$|\.html$/,
      threshold: 10240,
      minRatio: 0
    })
  ],

Retrieve WordPress root directory path?

I like @Omry Yadan's solution but I think it can be improved upon to use a loop in case you want to continue traversing up the directory tree until you find where wp-config.php actually lives. Of course, if you don't find it and end up in the server's root then all is lost and we return a sane value (false).

function wp_get_web_root() {

  $base = dirname(__FILE__);
  $path = false;

  while(!$path && '/' != $base) {
    if(@file_exists(dirname($base)).'/wp-config.php') {
      $path = dirname($base);
    } else {
      $base = dirname($base);
    }
  }

  return $path;
}

Get file name from URL

Beyond the all advanced methods, my simple trick is StringTokenizer:

import java.util.ArrayList;
import java.util.StringTokenizer;

public class URLName {
    public static void main(String args[]){
        String url = "http://www.example.com/some/path/to/a/file.xml";
        StringTokenizer tokens = new StringTokenizer(url, "/");

        ArrayList<String> parts = new ArrayList<>();

        while(tokens.hasMoreTokens()){
            parts.add(tokens.nextToken());
        }
        String file = parts.get(parts.size() -1);
        int dot = file.indexOf(".");
        String fileName = file.substring(0, dot);
        System.out.println(fileName);
    }
}

Is iterating ConcurrentHashMap values thread safe?

You may use this class to test two accessing threads and one mutating the shared instance of ConcurrentHashMap:

import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentMapIteration
{
  private final Map<String, String> map = new ConcurrentHashMap<String, String>();

  private final static int MAP_SIZE = 100000;

  public static void main(String[] args)
  {
    new ConcurrentMapIteration().run();
  }

  public ConcurrentMapIteration()
  {
    for (int i = 0; i < MAP_SIZE; i++)
    {
      map.put("key" + i, UUID.randomUUID().toString());
    }
  }

  private final ExecutorService executor = Executors.newCachedThreadPool();

  private final class Accessor implements Runnable
  {
    private final Map<String, String> map;

    public Accessor(Map<String, String> map)
    {
      this.map = map;
    }

    @Override
    public void run()
    {
      for (Map.Entry<String, String> entry : this.map.entrySet())
      {
        System.out.println(
            Thread.currentThread().getName() + " - [" + entry.getKey() + ", " + entry.getValue() + ']'
        );
      }
    }
  }

  private final class Mutator implements Runnable
  {

    private final Map<String, String> map;
    private final Random random = new Random();

    public Mutator(Map<String, String> map)
    {
      this.map = map;
    }

    @Override
    public void run()
    {
      for (int i = 0; i < 100; i++)
      {
        this.map.remove("key" + random.nextInt(MAP_SIZE));
        this.map.put("key" + random.nextInt(MAP_SIZE), UUID.randomUUID().toString());
        System.out.println(Thread.currentThread().getName() + ": " + i);
      }
    }
  }

  private void run()
  {
    Accessor a1 = new Accessor(this.map);
    Accessor a2 = new Accessor(this.map);
    Mutator m = new Mutator(this.map);

    executor.execute(a1);
    executor.execute(m);
    executor.execute(a2);
  }
}

No exception will be thrown.

Sharing the same iterator between accessor threads can lead to deadlock:

import java.util.Iterator;
import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentMapIteration
{
  private final Map<String, String> map = new ConcurrentHashMap<String, String>();
  private final Iterator<Map.Entry<String, String>> iterator;

  private final static int MAP_SIZE = 100000;

  public static void main(String[] args)
  {
    new ConcurrentMapIteration().run();
  }

  public ConcurrentMapIteration()
  {
    for (int i = 0; i < MAP_SIZE; i++)
    {
      map.put("key" + i, UUID.randomUUID().toString());
    }
    this.iterator = this.map.entrySet().iterator();
  }

  private final ExecutorService executor = Executors.newCachedThreadPool();

  private final class Accessor implements Runnable
  {
    private final Iterator<Map.Entry<String, String>> iterator;

    public Accessor(Iterator<Map.Entry<String, String>> iterator)
    {
      this.iterator = iterator;
    }

    @Override
    public void run()
    {
      while(iterator.hasNext()) {
        Map.Entry<String, String> entry = iterator.next();
        try
        {
          String st = Thread.currentThread().getName() + " - [" + entry.getKey() + ", " + entry.getValue() + ']';
        } catch (Exception e)
        {
          e.printStackTrace();
        }

      }
    }
  }

  private final class Mutator implements Runnable
  {

    private final Map<String, String> map;
    private final Random random = new Random();

    public Mutator(Map<String, String> map)
    {
      this.map = map;
    }

    @Override
    public void run()
    {
      for (int i = 0; i < 100; i++)
      {
        this.map.remove("key" + random.nextInt(MAP_SIZE));
        this.map.put("key" + random.nextInt(MAP_SIZE), UUID.randomUUID().toString());
      }
    }
  }

  private void run()
  {
    Accessor a1 = new Accessor(this.iterator);
    Accessor a2 = new Accessor(this.iterator);
    Mutator m = new Mutator(this.map);

    executor.execute(a1);
    executor.execute(m);
    executor.execute(a2);
  }
}

As soon as you start sharing the same Iterator<Map.Entry<String, String>> among accessor and mutator threads java.lang.IllegalStateExceptions will start popping up.

import java.util.Iterator;
import java.util.Map;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ConcurrentMapIteration
{
  private final Map<String, String> map = new ConcurrentHashMap<String, String>();
  private final Iterator<Map.Entry<String, String>> iterator;

  private final static int MAP_SIZE = 100000;

  public static void main(String[] args)
  {
    new ConcurrentMapIteration().run();
  }

  public ConcurrentMapIteration()
  {
    for (int i = 0; i < MAP_SIZE; i++)
    {
      map.put("key" + i, UUID.randomUUID().toString());
    }
    this.iterator = this.map.entrySet().iterator();
  }

  private final ExecutorService executor = Executors.newCachedThreadPool();

  private final class Accessor implements Runnable
  {
    private final Iterator<Map.Entry<String, String>> iterator;

    public Accessor(Iterator<Map.Entry<String, String>> iterator)
    {
      this.iterator = iterator;
    }

    @Override
    public void run()
    {
      while (iterator.hasNext())
      {
        Map.Entry<String, String> entry = iterator.next();
        try
        {
          String st =
              Thread.currentThread().getName() + " - [" + entry.getKey() + ", " + entry.getValue() + ']';
        } catch (Exception e)
        {
          e.printStackTrace();
        }

      }
    }
  }

  private final class Mutator implements Runnable
  {

    private final Random random = new Random();

    private final Iterator<Map.Entry<String, String>> iterator;

    private final Map<String, String> map;

    public Mutator(Map<String, String> map, Iterator<Map.Entry<String, String>> iterator)
    {
      this.map = map;
      this.iterator = iterator;
    }

    @Override
    public void run()
    {
      while (iterator.hasNext())
      {
        try
        {
          iterator.remove();
          this.map.put("key" + random.nextInt(MAP_SIZE), UUID.randomUUID().toString());
        } catch (Exception ex)
        {
          ex.printStackTrace();
        }
      }

    }
  }

  private void run()
  {
    Accessor a1 = new Accessor(this.iterator);
    Accessor a2 = new Accessor(this.iterator);
    Mutator m = new Mutator(map, this.iterator);

    executor.execute(a1);
    executor.execute(m);
    executor.execute(a2);
  }
}

How to apply a function to two columns of Pandas dataframe

The method you are looking for is Series.combine. However, it seems some care has to be taken around datatypes. In your example, you would (as I did when testing the answer) naively call

df['col_3'] = df.col_1.combine(df.col_2, func=get_sublist)

However, this throws the error:

ValueError: setting an array element with a sequence.

My best guess is that it seems to expect the result to be of the same type as the series calling the method (df.col_1 here). However, the following works:

df['col_3'] = df.col_1.astype(object).combine(df.col_2, func=get_sublist)

df

   ID   col_1   col_2   col_3
0   1   0   1   [a, b]
1   2   2   4   [c, d, e]
2   3   3   5   [d, e, f]

Display tooltip on Label's hover?

You can use the "title attribute" for label tag.

<label title="Hello This Will Have Some Value">Hello...</label>

If you need more control over the looks,

1 . try http://getbootstrap.com/javascript/#tooltips as shown below. But you will need to include bootstrap.

<button type="button" class="btn btn-default" data-toggle="tooltip" data-placement="left" title="Hello This Will Have Some Value">Hello...</button>

2 . try https://jqueryui.com/tooltip/. But you will need to include jQueryUI.

<script type="text/javascript">
$(document).ready(function(){
$(this).tooltip();
});
</script>

Javascript Click on Element by Class

If you want to click on all elements selected by some class, you can use this example (used on last.fm on the Loved tracks page to Unlove all).

var divs = document.querySelectorAll('.love-button.love-button--loved'); 

for (i = 0; i < divs.length; ++i) {
  divs[i].click();
};

With ES6 and Babel (cannot be run in the browser console directly)

[...document.querySelectorAll('.love-button.love-button--loved')]
   .forEach(div => { div.click(); })

create a text file using javascript

Try this:

<SCRIPT LANGUAGE="JavaScript">
 function WriteToFile(passForm) {

    set fso = CreateObject("Scripting.FileSystemObject");  
    set s = fso.CreateTextFile("C:\test.txt", True);
    s.writeline("HI");
    s.writeline("Bye");
    s.writeline("-----------------------------");
    s.Close();
 }
  </SCRIPT>

</head>

<body>
<p>To sign up for the Excel workshop please fill out the form below:
</p>
<form onSubmit="WriteToFile(this)">
Type your first name:
<input type="text" name="FirstName" size="20">
<br>Type your last name:
<input type="text" name="LastName" size="20">
<br>
<input type="submit" value="submit">
</form> 

This will work only on IE

How to get the list of files in a directory in a shell script?

for entry in "$search_dir"/* "$work_dir"/*
do
  if [ -f "$entry" ];then
    echo "$entry"
  fi
done

get the value of DisplayName attribute

Please try below code, I think this will solve your problem.

var classObj = new Class1();
classObj.Name => "StackOverflow";

var property = new Class1().GetType().GetProperty(nameof(classObj.Name));
var displayNameAttributeValue = (property ?? throw new InvalidOperationException())
    .GetCustomAttributes(typeof(DisplayNameAttribute)) as DisplayNameAttribute; 

if (displayNameAttributeValue != null)
{
   Console.WriteLine("{0} = {1}", displayNameAttributeValue, classObj.Name);
}

How to force the browser to reload cached CSS and JavaScript files

Interesting post. Having read all the answers here combined with the fact that I have never had any problems with "bogus" query strings (which I am unsure why everyone is so reluctant to use this) I guess the solution (which removes the need for Apache rewrite rules as in the accepted answer) is to compute a short hash of the CSS file contents (instead of the file datetime) as a bogus querystring.

This would result in the following:

<link rel="stylesheet" href="/css/base.css?[hash-here]" type="text/css" />

Of course, the datetime solutions also get the job done in the case of editing a CSS file, but I think it is about the CSS file content and not about the file datetime, so why get these mixed up?

How do I find files with a path length greater than 260 characters in Windows?

For paths greater than 260:
you can use:

Get-ChildItem | Where-Object {$_.FullName.Length -gt 260}

Example on 14 chars:
To view the paths lengths:

Get-ChildItem | Select-Object -Property FullName, @{Name="FullNameLength";Expression={($_.FullName.Length)}

Get paths greater than 14:

Get-ChildItem | Where-Object {$_.FullName.Length -gt 14}  

Screenshot:
enter image description here

For filenames greater than 10:

Get-ChildItem | Where-Object {$_.PSChildName.Length -gt 10}

Screenshot:
enter image description here

Mixing C# & VB In The Same Project

In our scenario, its a single VB.NET project (Windows Desktop application) in a single solution. However we wanted to take advantage of C# features like signed/unsigned integers and XML literals and string features in VB.NET. So depending on the features, at runtime we build the code file, compile using respective Rosalyn compiler (VB/CS) into DLL and dynamically load into current assembly. Of course we had to work on delinking, unloading, reloading, naming etc of the dynamic DLLs and the memory management were we largely used dynamic GUID for naming to avoid conflict. It works fine where app user may connect to any DB from our desktop app, write SQL query, convert the connection to LINQ connection and write LINQ queries too which all requires dynamic building of source code, compiling into DLL and attaching to current assembly.

How to reference a .css file on a razor view?

I prefer to use the razor html helper from Client Dependency dll

Html.RequireCss("yourfile", 9999); // 9999 is loading priority 

How to change icon on Google map marker

Manish, Eden after your suggestion: here is the code. But still showing the red(Default) icon.

<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>

<script type="text/javascript">
var markers = [
            {
            "title": 'This is title',
            "lat": '-37.801578',
            "lng": '145.060508',
        "icon": 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_green.png',
            "description": 'Vikash Rathee. <br/><a href="http://www.pricingindia.in/pincode.aspx">Pin Code by City</a>'
        }
];
</script>
<script type="text/javascript">
    window.onload = function () {
        var mapOptions = {
            center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
            zoom: 10,
            flat: true,
            styles: [ { "stylers": [ { "hue": "#4bd6bf" }, { "gamma": "1.58" } ] } ],
            mapTypeId: google.maps.MapTypeId.ROADMAP
        };
        var infoWindow = new google.maps.InfoWindow();
        var map = new google.maps.Map(document.getElementById("dvMap"), mapOptions);
        for (i = 0; i < markers.length; i++) {
            var data = markers[i]
            var myLatlng = new google.maps.LatLng(data.lat, data.lng);
            var marker = new google.maps.Marker({
                position: myLatlng,
                map: map,
        icon: markers[i][3],
                title: data.title
            });
            (function (marker, data) {
                google.maps.event.addListener(marker, "click", function (e) {
                    infoWindow.setContent(data.description);
                    infoWindow.open(map, marker);
                });
            })(marker, data);
        }
    }
</script>


<div id="dvMap" style="width: 100%; height: 100%">
</div>

How do I edit an incorrect commit message in git ( that I've pushed )?

At our shop, I introduced the convention of adding recognizably named annotated tags to commits with incorrect messages, and using the annotation as the replacement.

Even though this doesn't help folks who run casual "git log" commands, it does provide us with a way to fix incorrect bug tracker references in the comments, and all my build and release tools understand the convention.

This is obviously not a generic answer, but it might be something folks can adopt within specific communities. I'm sure if this is used on a larger scale, some sort of porcelain support for it may crop up, eventually...

Laravel use same form for create and edit

For the creation add an empty object to the view.

return view('admin.profiles.create', ['profile' => new Profile()]);

Old function has a second parameter, default value, if you pass there the object's field, the input can be reused.

<input class="input" type="text" name="name" value="{{old('name', $profile->name)}}">

For the form action, you can use the correct endpoint.

<form action="{{ $profile->id == null ? '/admin/profiles' :  '/admin/profiles/' . $profile->id }} " method="POST">

And for the update you have to use PATCH method.

@isset($profile->id)
 {{ method_field('PATCH')}}
@endisset

Check folder size in Bash

# 10GB
SIZE="10"


# check the current size
CHECK="`du -hs /media/662499e1-b699-19ad-57b3-acb127aa5a2b/Aufnahmen`"
CHECK=${CHECK%G*}
echo "Current Foldersize: $CHECK GB"

if (( $(echo "$CHECK > $SIZE" |bc -l) )); then
        echo "Folder is bigger than $SIZE GB"
else
        echo "Folder is smaller than $SIZE GB"
fi

How to get user name using Windows authentication in asp.net?

This should work:

User.Identity.Name

Identity returns an IPrincipal

Here is the link to the Microsoft documentation.

Groovy built-in REST/HTTP client?

You can take advantage of Groovy features like with(), improvements to URLConnection, and simplified getters/setters:

GET:

String getResult = new URL('http://mytestsite/bloop').text

POST:

String postResult
((HttpURLConnection)new URL('http://mytestsite/bloop').openConnection()).with({
    requestMethod = 'POST'
    doOutput = true
    setRequestProperty('Content-Type', '...') // Set your content type.
    outputStream.withPrintWriter({printWriter ->
        printWriter.write('...') // Your post data. Could also use withWriter() if you don't want to write a String.
    })
    // Can check 'responseCode' here if you like.
    postResult = inputStream.text // Using 'inputStream.text' because 'content' will throw an exception when empty.
})

Note, the POST will start when you try to read a value from the HttpURLConnection, such as responseCode, inputStream.text, or getHeaderField('...').

Store images in a MongoDB database

You can try this one:

String newFileName = "my-image";
File imageFile = new File("/users/victor/images/image.png");
GridFS gfsPhoto = new GridFS(db, "photo");
GridFSInputFile gfsFile = gfsPhoto.createFile(imageFile);
gfsFile.setFilename(newFileName);
gfsFile.save();

how to get last insert id after insert query in codeigniter active record

From the documentation:

$this->db->insert_id()

The insert ID number when performing database inserts.

Therefore, you could use something like this:

$lastid = $this->db->insert_id();

How do I call a Django function on button click?

here is a pure-javascript, minimalistic approach. I use JQuery but you can use any library (or even no libraries at all).

<html>
    <head>
        <title>An example</title>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
        <script>
            function call_counter(url, pk) {
                window.open(url);
                $.get('YOUR_VIEW_HERE/'+pk+'/', function (data) {
                    alert("counter updated!");
                });
            }
        </script>
    </head>
    <body>
        <button onclick="call_counter('http://www.google.com', 12345);">
            I update object 12345
        </button>
        <button onclick="call_counter('http://www.yahoo.com', 999);">
            I update object 999
        </button>
    </body>
</html>

Alternative approach

Instead of placing the JavaScript code, you can change your link in this way:

<a target="_blank" 
    class="btn btn-info pull-right" 
    href="{% url YOUR_VIEW column_3_item.pk %}/?next={{column_3_item.link_for_item|urlencode:''}}">
    Check It Out
</a>

and in your views.py:

def YOUR_VIEW_DEF(request, pk):
    YOUR_OBJECT.objects.filter(pk=pk).update(views=F('views')+1)
    return HttpResponseRedirect(request.GET.get('next')))

How to check if a String contains only ASCII?

//return is uppercase or lowercase
public boolean isASCIILetter(char c) {
  return (c > 64 && c < 91) || (c > 96 && c < 123);
}

How to display my location on Google Maps for Android API v2

Before enabling the My Location layer, you must request location permission from the user. This sample does not include a request for location permission.

To simplify, in terms of lines of code, the request for the location permit can be made using the library EasyPermissions.

Then following the example of the official documentation of The My Location Layer my code works as follows for all versions of Android that contain Google services.

  1. Create an activity that contains a map and implements the interfaces OnMyLocationClickListener y OnMyLocationButtonClickListener.
  2. Define in app/build.gradle implementation 'pub.devrel:easypermissions:2.0.1'
  3. Forward results to EasyPermissions within method onRequestPermissionsResult()

    EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);

  4. Request permission and operate according to the user's response with requestLocationPermission()

  5. Call requestLocationPermission() and set the listeners to onMapReady().

MapsActivity.java

public class MapsActivity extends FragmentActivity implements 
    OnMapReadyCallback,
    GoogleMap.OnMyLocationClickListener,
    GoogleMap.OnMyLocationButtonClickListener {

    private final int REQUEST_LOCATION_PERMISSION = 1;

    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        requestLocationPermission();
        mMap.setOnMyLocationButtonClickListener(this);
        mMap.setOnMyLocationClickListener(this);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        // Forward results to EasyPermissions
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

    @SuppressLint("MissingPermission")
    @AfterPermissionGranted(REQUEST_LOCATION_PERMISSION)
    public void requestLocationPermission() {
        String[] perms = {Manifest.permission.ACCESS_FINE_LOCATION};
        if(EasyPermissions.hasPermissions(this, perms)) {
            mMap.setMyLocationEnabled(true);
            Toast.makeText(this, "Permission already granted", Toast.LENGTH_SHORT).show();
        }
        else {
            EasyPermissions.requestPermissions(this, "Please grant the location permission", REQUEST_LOCATION_PERMISSION, perms);
        }
    }

    @Override
    public boolean onMyLocationButtonClick() {
        Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show();
        return false;
    }

    @Override
    public void onMyLocationClick(@NonNull Location location) {
        Toast.makeText(this, "Current location:\n" + location, Toast.LENGTH_LONG).show();
    }
}

Source

How do I create an empty array/matrix in NumPy?

A NumPy array is a very different data structure from a list and is designed to be used in different ways. Your use of hstack is potentially very inefficient... every time you call it, all the data in the existing array is copied into a new one. (The append function will have the same issue.) If you want to build up your matrix one column at a time, you might be best off to keep it in a list until it is finished, and only then convert it into an array.

e.g.


mylist = []
for item in data:
    mylist.append(item)
mat = numpy.array(mylist)

item can be a list, an array or any iterable, as long as each item has the same number of elements.
In this particular case (data is some iterable holding the matrix columns) you can simply use


mat = numpy.array(data)

(Also note that using list as a variable name is probably not good practice since it masks the built-in type by that name, which can lead to bugs.)

EDIT:

If for some reason you really do want to create an empty array, you can just use numpy.array([]), but this is rarely useful!

How to get 'System.Web.Http, Version=5.2.3.0?

I did Install-Package Microsoft.AspNet.WebApi.Core -version 5.2.3 but it still did not work. Then looked in my project bin folder and saw that it still had the old System.Web.Mvc file.

So I manually copied the newer file from the package to the bin folder. Then I was up and running again.

Python: Ignore 'Incorrect padding' error when base64 decoding

I ran into this problem as well and nothing worked. I finally managed to find the solution which works for me. I had zipped content in base64 and this happened to 1 out of a million records...

This is a version of the solution suggested by Simon Sapin.

In case the padding is missing 3 then I remove the last 3 characters.

Instead of "0gA1RD5L/9AUGtH9MzAwAAA=="

We get "0gA1RD5L/9AUGtH9MzAwAA"

        missing_padding = len(data) % 4
        if missing_padding == 3:
            data = data[0:-3]
        elif missing_padding != 0:
            print ("Missing padding : " + str(missing_padding))
            data += '=' * (4 - missing_padding)
        data_decoded = base64.b64decode(data)   

According to this answer Trailing As in base64 the reason is nulls. But I still have no idea why the encoder messes this up...

What is the { get; set; } syntax in C#?

A property is a like a layer that separates the private variable from other members of a class. From outside world it feels like a property is just a field, a property can be accessed using .Property

public class Person
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string FullName => $"{FirstName} {LastName}";
}

public class Person
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string FullName { get { return $"{FirstName} {LastName}"; } }
}

FullName is a Property. The one with arrow is a shortcut. From outside world, we can access FullName like this:

var person = new Person();
Console.WriteLine(person.FullName);

Callers do not care about how you implemented the FullName. But inside the class you can change FullName whatever you want.

Check out Microsoft Documentation for more detailed explanation:

https://docs.microsoft.com/en-us/dotnet/csharp/properties

How do you fix a bad merge, and replay your good commits onto a fixed merge?

The simplest way I found was suggested by leontalbot (as a comment), which is a post published by Anoopjohn. I think its worth its own space as an answer:

(I converted it to a bash script)

#!/bin/bash
if [[ $1 == "" ]]; then
    echo "Usage: $0 FILE_OR_DIR [remote]";
    echo "FILE_OR_DIR: the file or directory you want to remove from history"
    echo "if 'remote' argument is set, it will also push to remote repository."
    exit;
fi
FOLDERNAME_OR_FILENAME=$1;

#The important part starts here: ------------------------

git filter-branch -f --index-filter "git rm -rf --cached --ignore-unmatch $FOLDERNAME_OR_FILENAME" -- --all
rm -rf .git/refs/original/
git reflog expire --expire=now --all
git gc --prune=now
git gc --aggressive --prune=now

if [[ $2 == "remote" ]]; then
    git push --all --force
fi
echo "Done."

All credits goes to Annopjohn, and to leontalbot for pointing it out.

NOTE

Be aware that the script doesn't include validations, so be sure you don't make mistakes and that you have a backup in case something goes wrong. It worked for me, but it may not work in your situation. USE IT WITH CAUTION (follow the link if you want to know what is going on).

Remove a child with a specific attribute, in SimpleXML for PHP

Idea about helper functions is from one of the comments for DOM on php.net and idea about using unset is from kavoir.com. For me this solution finally worked:

function Myunset($node)
{
 unsetChildren($node);
 $parent = $node->parentNode;
 unset($node);
}

function unsetChildren($node)
{
 while (isset($node->firstChild))
 {
 unsetChildren($node->firstChild);
 unset($node->firstChild);
 }
}

using it: $xml is SimpleXmlElement

Myunset($xml->channel->item[$i]);

The result is stored in $xml, so don’t worry about assigning it to any variable.

Display images in asp.net mvc

Make sure you image is a relative path such as:

@Url.Content("~/Content/images/myimage.png")

MVC4

<img src="~/Content/images/myimage.png" />

You could convert the byte[] into a Base64 string on the fly.

string base64String = Convert.ToBase64String(imageBytes);

<img src="@String.Format("data:image/png;base64,{0}", base64string)" />

How to test if a double is zero?

Numeric primitives in class scope are initialized to zero when not explicitly initialized.

Numeric primitives in local scope (variables in methods) must be explicitly initialized.

If you are only worried about division by zero exceptions, checking that your double is not exactly zero works great.

if(value != 0)
    //divide by value is safe when value is not exactly zero.

Otherwise when checking if a floating point value like double or float is 0, an error threshold is used to detect if the value is near 0, but not quite 0.

public boolean isZero(double value, double threshold){
    return value >= -threshold && value <= threshold;
}

Building with Lombok's @Slf4j and Intellij: Cannot find symbol log

In addition to having Lombok plugin installed, also make sure that the "Enable annotation processing" checkbox is ticked under:

Preferences > Compiler > Annotation Processors

Note: starting with IntelliJ 2017, the "Enable Annotation Processing" checkbox has moved to:

Settings > Build, Execution, Deployment > Compiler > Annotation Processors

Touch move getting stuck Ignored attempt to cancel a touchmove

I know this is an old post but I had a lot of issues trying to solve this and I finally did so I wanted to share.

My issue was that I was adding an event listener within the ontouchstart and removing it in the ontouchend functions - something like this

function onTouchStart() {
  window.addEventListener("touchmove", handleTouchMove, {
    passive: false
  });
}

function onTouchEnd() {
  window.removeEventListener("touchmove", handleTouchMove, {
    passive: true
  });
}

function handleTouchMove(e) {
  e.preventDefault();
}

For some reason adding it removing it like this was causing this issue of the event randomly not being cancelable. So to solve this I kept the listener active and toggled a boolean on whether or not it should prevent the event - something like this:

let stopScrolling = false;

window.addEventListener("touchmove", handleTouchMove, {
  passive: false
});

function handleTouchMove(e) {
  if (!stopScrolling) {
    return;
  }
  e.preventDefault();
}

function onTouchStart() {
  stopScrolling = true;
}

function onTouchEnd() {
  stopScrolling = false;
}

I was actually using React so my solution involved setting state, but I've simplified it for a more generic solution. Hopefully this helps someone!

Any way to write a Windows .bat file to kill processes?

Please find the below logic where it works on the condition.

If we simply call taskkill /im applicationname.exe, it will kill only if this process is running. If this process is not running, it will throw an error.

So as to check before takskill is called, a check can be done to make sure execute taskkill will be executed only if the process is running, so that it won't throw error.

tasklist /fi "imagename eq applicationname.exe" |find ":" > nul

if errorlevel 1 taskkill /f /im "applicationname.exe"

Why is Git better than Subversion?

With Git, you can do practically anything offline, because everybody has their own repository.

Making branches and merging between branches is really easy.

Even if you don't have commit rights for a project, you can still have your own repository online, and publish "push requests" for your patches. Everybody who likes your patches can pull them into their project, including the official maintainers.

It's trivial to fork a project, modify it, and still keep merging in the bugfixes from the HEAD branch.

Git works for the Linux kernel developers. That means it is really fast (it has to be), and scales to thousands of contributors. Git also uses less space (up to 30 times less space for the Mozilla repository).

Git is very flexible, very TIMTOWTDI (There is more than one way to do it). You can use whatever workflow you want, and Git will support it.

Finally, there's GitHub, a great site for hosting your Git repositories.

Drawbacks of Git:

  • it's much harder to learn, because Git has more concepts and more commands.
  • revisions don't have version numbers like in subversion
  • many Git commands are cryptic, and error messages are very user-unfriendly
  • it lacks a good GUI (such as the great TortoiseSVN)

Android emulator doesn't take keyboard input - SDK tools rev 20

Just in case somebody finds it usefull.

I had a problem with the KEYCODE_DPAD_UP it belongs to the trackBall. to solve this change your avdfolder/config.ini hw.trackBall=yes and push DEL or F6

Is it possible to 'prefill' a google form using data from a google spreadsheet?

You can create a pre-filled form URL from within the Form Editor, as described in the documentation for Drive Forms. You'll end up with a URL like this, for example:

https://docs.google.com/forms/d/--form-id--/viewform?entry.726721210=Mike+Jones&entry.787184751=1975-05-09&entry.1381372492&entry.960923899

buildUrls()

In this example, question 1, "Name", has an ID of 726721210, while question 2, "Birthday" is 787184751. Questions 3 and 4 are blank.

You could generate the pre-filled URL by adapting the one provided through the UI to be a template, like this:

function buildUrls() {
  var template = "https://docs.google.com/forms/d/--form-id--/viewform?entry.726721210=##Name##&entry.787184751=##Birthday##&entry.1381372492&entry.960923899";
  var ss = SpreadsheetApp.getActive().getSheetByName("Sheet1");  // Email, Name, Birthday
  var data = ss.getDataRange().getValues();

  // Skip headers, then build URLs for each row in Sheet1.
  for (var i = 1; i < data.length; i++ ) {
    var url = template.replace('##Name##',escape(data[i][1]))
                      .replace('##Birthday##',data[i][2].yyyymmdd());  // see yyyymmdd below
    Logger.log(url);  // You could do something more useful here.
  }
};

This is effective enough - you could email the pre-filled URL to each person, and they'd have some questions already filled in.

betterBuildUrls()

Instead of creating our template using brute force, we can piece it together programmatically. This will have the advantage that we can re-use the code without needing to remember to change the template.

Each question in a form is an item. For this example, let's assume the form has only 4 questions, as you've described them. Item [0] is "Name", [1] is "Birthday", and so on.

We can create a form response, which we won't submit - instead, we'll partially complete the form, only to get the pre-filled form URL. Since the Forms API understands the data types of each item, we can avoid manipulating the string format of dates and other types, which simplifies our code somewhat.

(EDIT: There's a more general version of this in How to prefill Google form checkboxes?)

/**
 * Use Form API to generate pre-filled form URLs
 */
function betterBuildUrls() {
  var ss = SpreadsheetApp.getActive();
  var sheet = ss.getSheetByName("Sheet1");
  var data = ss.getDataRange().getValues();  // Data for pre-fill

  var formUrl = ss.getFormUrl();             // Use form attached to sheet
  var form = FormApp.openByUrl(formUrl);
  var items = form.getItems();

  // Skip headers, then build URLs for each row in Sheet1.
  for (var i = 1; i < data.length; i++ ) {
    // Create a form response object, and prefill it
    var formResponse = form.createResponse();

    // Prefill Name
    var formItem = items[0].asTextItem();
    var response = formItem.createResponse(data[i][1]);
    formResponse.withItemResponse(response);

    // Prefill Birthday
    formItem = items[1].asDateItem();
    response = formItem.createResponse(data[i][2]);
    formResponse.withItemResponse(response);

    // Get prefilled form URL
    var url = formResponse.toPrefilledUrl();
    Logger.log(url);  // You could do something more useful here.
  }
};

yymmdd Function

Any date item in the pre-filled form URL is expected to be in this format: yyyy-mm-dd. This helper function extends the Date object with a new method to handle the conversion.

When reading dates from a spreadsheet, you'll end up with a javascript Date object, as long as the format of the data is recognizable as a date. (Your example is not recognizable, so instead of May 9th 1975 you could use 5/9/1975.)

// From http://blog.justin.kelly.org.au/simple-javascript-function-to-format-the-date-as-yyyy-mm-dd/
Date.prototype.yyyymmdd = function() {
  var yyyy = this.getFullYear().toString();                                    
  var mm = (this.getMonth()+1).toString(); // getMonth() is zero-based         
  var dd  = this.getDate().toString();             

  return yyyy + '-' + (mm[1]?mm:"0"+mm[0]) + '-' + (dd[1]?dd:"0"+dd[0]);
};

Reset par to the default values at startup

dev.off() is the best function, but it clears also all plots. If you want to keep plots in your window, at the beginning save default par settings:

def.par = par()

Then when you use your par functions you still have a backup of default par settings. Later on, after generating plots, finish with:

par(def.par) #go back to default par settings

With this, you keep generated plots and reset par settings.

How to match hyphens with Regular Expression?

use "\p{Pd}" without quotes to match any type of hyphen. The '-' character is just one type of hyphen which also happens to be a special character in Regex.

How do you append to a file?

You need to open the file in append mode, by setting "a" or "ab" as the mode. See open().

When you open with "a" mode, the write position will always be at the end of the file (an append). You can open with "a+" to allow reading, seek backwards and read (but all writes will still be at the end of the file!).

Example:

>>> with open('test1','wb') as f:
        f.write('test')
>>> with open('test1','ab') as f:
        f.write('koko')
>>> with open('test1','rb') as f:
        f.read()
'testkoko'

Note: Using 'a' is not the same as opening with 'w' and seeking to the end of the file - consider what might happen if another program opened the file and started writing between the seek and the write. On some operating systems, opening the file with 'a' guarantees that all your following writes will be appended atomically to the end of the file (even as the file grows by other writes).


A few more details about how the "a" mode operates (tested on Linux only). Even if you seek back, every write will append to the end of the file:

>>> f = open('test','a+') # Not using 'with' just to simplify the example REPL session
>>> f.write('hi')
>>> f.seek(0)
>>> f.read()
'hi'
>>> f.seek(0)
>>> f.write('bye') # Will still append despite the seek(0)!
>>> f.seek(0)
>>> f.read()
'hibye'

In fact, the fopen manpage states:

Opening a file in append mode (a as the first character of mode) causes all subsequent write operations to this stream to occur at end-of-file, as if preceded the call:

fseek(stream, 0, SEEK_END);

Old simplified answer (not using with):

Example: (in a real program use with to close the file - see the documentation)

>>> open("test","wb").write("test")
>>> open("test","a+b").write("koko")
>>> open("test","rb").read()
'testkoko'

OpenJDK availability for Windows OS

OpenSCG maintains OpenJDK 6 installers for 32-bit Windows and other operating systems.

To configure it, create a JAVA_HOME environment variable and set it to C:\OpenSCG\openjdk-6.0.24 or whatever is the current version. Then add %JAVA_HOME%\bin; to the beginning of your PATH environment variable.

You can edit your environment variables by contextual clicking (My) Computer, selecting Properties, clicking Advanced system settings if you’re in Windows 7, clicking the Advanced tab and then clicking Environment Variables.

javascript convert int to float

toFixed() method formats a number using fixed-point notation. Read MDN Web Docs for full reference.

var fval = 4;

console.log(fval.toFixed(2)); // prints 4.00

How to select an element with 2 classes

Just chain them together:

.a.b {
  color: #666;
}

onChange and onSelect in DropDownList

hmm. why don't you use onClick()

<select id="mySelect" onChange="enable();">
   <option onClick="disable();">No</option>
   <option onClick="enable();">Yes</option>
</select>

Laravel Eloquent "WHERE NOT IN"

$created_po = array();
     $challan = modelname::where('fieldname','!=', 0)->get();
     // dd($challan);
     foreach ($challan as $rec){
         $created_po[] = array_push($created_po,$rec->fieldname);
     }
     $data = modelname::whereNotIn('fieldname',$created_po)->orderBy('fieldname','desc')->with('modelfunction')->get();

How to start an application without waiting in a batch file?

I'm making a guess here, but your start invocation probably looks like this:

start "\Foo\Bar\Path with spaces in it\program.exe"

This will open a new console window, using “\Foo\Bar\Path with spaces in it\program.exe” as its title.

If you use start with something that is (or needs to be) surrounded by quotes, you need to put empty quotes as the first argument:

start "" "\Foo\Bar\Path with spaces in it\program.exe"

This is because start interprets the first quoted argument it finds as the window title for a new console window.

Twitter Bootstrap add active class to li

Just in case you are using Boostrap in Angulajs: this is a simple directive that works for me (because data-toggle cited by Kam is not included in Angular-ui). Hope can help.

app.directive("myDataToggle", function(){
    function link(scope, element, attrs) {
        var e = angular.element(element);
        e.on('click', function(){
            e.parent().parent().children().removeClass('active');
            e.parent().addClass("active");
        })
    }
    return {
        restrict: 'A',
        link: link
    };
});

<ul class="nav nav-sidebar">
    <li><a href="#/page1" my-data-toggle>Page1</a></li>
    <li><a href="#/page2" my-data-toggle>Page2</a></li>
    <li><a href="#/page3" my-data-toggle>Page3</a></li>
</ul>

Accessing post variables using Java Servlets

For getting all post parameters there is Map which contains request param name as key and param value as key.

Map params = servReq.getParameterMap();

And to get parameters with known name normal

String userId=servReq.getParameter("user_id");

How to insert &nbsp; in XSLT

&#160; works really well. However, it will display one of those strange characters in ANSI encoding. <xsl:text> worked best for me.

<xsl:text> </xsl:text>

Server.UrlEncode vs. HttpUtility.UrlEncode

I had significant headaches with these methods before, I recommend you avoid any variant of UrlEncode, and instead use Uri.EscapeDataString - at least that one has a comprehensible behavior.

Let's see...

HttpUtility.UrlEncode(" ") == "+" //breaks ASP.NET when used in paths, non-
                                  //standard, undocumented.
Uri.EscapeUriString("a?b=e") == "a?b=e" // makes sense, but rarely what you
                                        // want, since you still need to
                                        // escape special characters yourself

But my personal favorite has got to be HttpUtility.UrlPathEncode - this thing is really incomprehensible. It encodes:

  • " " ==> "%20"
  • "100% true" ==> "100%%20true" (ok, your url is broken now)
  • "test A.aspx#anchor B" ==> "test%20A.aspx#anchor%20B"
  • "test A.aspx?hmm#anchor B" ==> "test%20A.aspx?hmm#anchor B" (note the difference with the previous escape sequence!)

It also has the lovelily specific MSDN documentation "Encodes the path portion of a URL string for reliable HTTP transmission from the Web server to a client." - without actually explaining what it does. You are less likely to shoot yourself in the foot with an Uzi...

In short, stick to Uri.EscapeDataString.

How to stop and restart memcached server?

If you're using homebrew:

brew services restart memcached

Smooth scroll to specific div on click

I took the Ned Rockson's version and adjusted it to allow upwards scrolls as well.

var smoothScroll = function(elementId) {
  var MIN_PIXELS_PER_STEP = 16;
  var MAX_SCROLL_STEPS = 30;
  var target = document.getElementById(elementId);
  var scrollContainer = target;
  do {
    scrollContainer = scrollContainer.parentNode;
    if (!scrollContainer) return;
    scrollContainer.scrollTop += 1;
  } while (scrollContainer.scrollTop === 0);

  var targetY = 0;
  do {
    if (target === scrollContainer) break;
    targetY += target.offsetTop;
  } while (target = target.offsetParent);

  var pixelsPerStep = Math.max(MIN_PIXELS_PER_STEP,
    Math.abs(targetY - scrollContainer.scrollTop) / MAX_SCROLL_STEPS);

  var isUp = targetY < scrollContainer.scrollTop;

  var stepFunc = function() {
    if (isUp) {
      scrollContainer.scrollTop = Math.max(targetY, scrollContainer.scrollTop - pixelsPerStep);
      if (scrollContainer.scrollTop <= targetY) {
        return;
      }
    } else {
        scrollContainer.scrollTop = Math.min(targetY, scrollContainer.scrollTop + pixelsPerStep);

      if (scrollContainer.scrollTop >= targetY) {
        return;
      }
    }

    window.requestAnimationFrame(stepFunc);
  };

  window.requestAnimationFrame(stepFunc);
};

JSONResult to String

You're looking for the JavaScriptSerializer class, which is used internally by JsonResult:

string json = new JavaScriptSerializer().Serialize(jsonResult.Data);

Check date between two other dates spring data jpa

You should take a look the reference documentation. It's well explained.

In your case, I think you cannot use between because you need to pass two parameters

Between - findByStartDateBetween … where x.startDate between ?1 and ?2

In your case take a look to use a combination of LessThan or LessThanEqual with GreaterThan or GreaterThanEqual

  • LessThan/LessThanEqual

LessThan - findByEndLessThan … where x.start< ?1

LessThanEqual findByEndLessThanEqual … where x.start <= ?1

  • GreaterThan/GreaterThanEqual

GreaterThan - findByStartGreaterThan … where x.end> ?1

GreaterThanEqual - findByStartGreaterThanEqual … where x.end>= ?1

You can use the operator And and Or to combine both.

Facebook share link without JavaScript

You can use the Feed URL "Direct URL" option, as described on the Feed Dialog page:

You can also bring up a Feed Dialog by explicitly directing the user to the /dialog/feed endpoint:

  https://www.facebook.com/dialog/feed?  
  app_id=123050457758183&
  link=https://developers.facebook.com/docs/reference/dialogs/&
  picture=http://fbrell.com/f8.jpg&
  name=Facebook%20Dialogs&
  caption=Reference%20Documentation&
  description=Using%20Dialogs%20to%20interact%20with%20users.&
  redirect_uri=http://www.example.com/response`

Looks like they no longer mention "sharing" anywhere in their docs; this has been replaced with the concept of adding to your Feed.

Difference between "char" and "String" in Java

char is one character. String is zero or more characters.

char is a primitive type. String is a class.

char c = 'a';
String s = "Hi!";

Note the single quotes for char, and double quotes for String.

How can I make a link from a <td> table cell

Here is my solution:

<td>
   <a href="/yourURL"></a>
   <div class="item-container">
      <img class="icon" src="/iconURL" />
      <p class="name">
         SomeText
      </p>
   </div>
</td>

(LESS)

td {
  padding: 1%;
  vertical-align: bottom;
  position:relative;

     a {
        height: 100%;
        display: block;
        position: absolute;
        top:0;
        bottom:0;
        right:0;
        left:0;
       }

     .item-container {
         /*...*/
     }
}

Like this you can still benefit from some table cell properties like vertical-align. (Tested on Chrome)

Database cluster and load balancing

Database clustering is a bit of an ambiguous term, some vendors consider a cluster having two or more servers share the same storage, some others call a cluster a set of replicated servers.

Replication defines the method by which a set of servers remain synchronized without having to share the storage being able to be geographically disperse, there are two main ways of going about it:

  • master-master (or multi-master) replication: Any server can update the database. It is usually taken care of by a different module within the database (or a whole different software running on top of them in some cases).

    Downside is that it is very hard to do well, and some systems lose ACID properties when in this mode of replication.

    Upside is that it is flexible and you can support the failure of any server while still having the database updated.

  • master-slave replication: There is only a single copy of authoritative data, which is the pushed to the slave servers.

    Downside is that it is less fault tolerant, if the master dies, there are no further changes in the slaves.

    Upside is that it is easier to do than multi-master and it usually preserve ACID properties.

Load balancing is a different concept, it consists distributing the queries sent to those servers so the load is as evenly distributed as possible. It is usually done at the application layer (or with a connection pool). The only direct relation between replication and load balancing is that you need some replication to be able to load balance, else you'd have a single server.

All possible array initialization syntaxes

Another way of creating and initializing an array of objects. This is similar to the example which @Amol has posted above, except this one uses constructors. A dash of polymorphism sprinkled in, I couldn't resist.

IUser[] userArray = new IUser[]
{
    new DummyUser("[email protected]", "Gibberish"),
    new SmartyUser("[email protected]", "Italian", "Engineer")
};

Classes for context:

interface IUser
{
    string EMail { get; }       // immutable, so get only an no set
    string Language { get; }
}

public class DummyUser : IUser
{
    public DummyUser(string email, string language)
    {
        m_email = email;
        m_language = language;
    }

    private string m_email;
    public string EMail
    {
        get { return m_email; }
    }

    private string m_language;
    public string Language
    {
        get { return m_language; }
    }
}

public class SmartyUser : IUser
{
    public SmartyUser(string email, string language, string occupation)
    {
        m_email = email;
        m_language = language;
        m_occupation = occupation;
    }

    private string m_email;
    public string EMail
    {
        get { return m_email; }
    }

    private string m_language;
    public string Language
    {
        get { return m_language; }
    }

    private string m_occupation;
}

Running command line silently with VbScript and getting output?

I have taken this and various other comments and created a bit more advanced function for running an application and getting the output.

Example to Call Function: Will output the DIR list of C:\ for Directories only. The output will be returned to the variable CommandResults as well as remain in C:\OUTPUT.TXT.

CommandResults = vFn_Sys_Run_CommandOutput("CMD.EXE /C DIR C:\ /AD",1,1,"C:\OUTPUT.TXT",0,1)

Function

Function vFn_Sys_Run_CommandOutput (Command, Wait, Show, OutToFile, DeleteOutput, NoQuotes)
'Run Command similar to the command prompt, for Wait use 1 or 0. Output returned and
'stored in a file.
'Command = The command line instruction you wish to run.
'Wait = 1/0; 1 will wait for the command to finish before continuing.
'Show = 1/0; 1 will show for the command window.
'OutToFile = The file you wish to have the output recorded to.
'DeleteOutput = 1/0; 1 deletes the output file. Output is still returned to variable.
'NoQuotes = 1/0; 1 will skip wrapping the command with quotes, some commands wont work
'                if you wrap them in quotes.
'----------------------------------------------------------------------------------------
  On Error Resume Next
  'On Error Goto 0
    Set f_objShell = CreateObject("Wscript.Shell")
    Set f_objFso = CreateObject("Scripting.FileSystemObject")
    Const ForReading = 1, ForWriting = 2, ForAppending = 8
      'VARIABLES
        If OutToFile = "" Then OutToFile = "TEMP.TXT"
        tCommand = Command
        If Left(Command,1)<>"""" And NoQuotes <> 1 Then tCommand = """" & Command & """"
        tOutToFile = OutToFile
        If Left(OutToFile,1)<>"""" Then tOutToFile = """" & OutToFile & """"
        If Wait = 1 Then tWait = True
        If Wait <> 1 Then tWait = False
        If Show = 1 Then tShow = 1
        If Show <> 1 Then tShow = 0
      'RUN PROGRAM
        f_objShell.Run tCommand & ">" & tOutToFile, tShow, tWait
      'READ OUTPUT FOR RETURN
        Set f_objFile = f_objFso.OpenTextFile(OutToFile, 1)
          tMyOutput = f_objFile.ReadAll
          f_objFile.Close
          Set f_objFile = Nothing
      'DELETE FILE AND FINISH FUNCTION
        If DeleteOutput = 1 Then
          Set f_objFile = f_objFso.GetFile(OutToFile)
            f_objFile.Delete
            Set f_objFile = Nothing
          End If
        vFn_Sys_Run_CommandOutput = tMyOutput
        If Err.Number <> 0 Then vFn_Sys_Run_CommandOutput = "<0>"
        Err.Clear
        On Error Goto 0
      Set f_objFile = Nothing
      Set f_objShell = Nothing
  End Function

e.printStackTrace equivalent in python

Adding to the other great answers, we can use the Python logging library's debug(), info(), warning(), error(), and critical() methods. Quoting from the docs for Python 3.7.4,

There are three keyword arguments in kwargs which are inspected: exc_info which, if it does not evaluate as false, causes exception information to be added to the logging message.

What this means is, you can use the Python logging library to output a debug(), or other type of message, and the logging library will include the stack trace in its output. With this in mind, we can do the following:

import logging

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)

def f():
    a = { 'foo': None }
    # the following line will raise KeyError
    b = a['bar']

def g():
    f()

try:
    g()
except Exception as e:
    logger.error(str(e), exc_info=True)

And it will output:

'bar'
Traceback (most recent call last):
  File "<ipython-input-2-8ae09e08766b>", line 18, in <module>
    g()
  File "<ipython-input-2-8ae09e08766b>", line 14, in g
    f()
  File "<ipython-input-2-8ae09e08766b>", line 10, in f
    b = a['bar']
KeyError: 'bar'

If else embedding inside html

<?php if ($foo) { ?>
    <div class="mydiv">Condition is true</div>
<?php } else { ?>
    <div class="myotherdiv">Condition is false</div>
<?php } ?>

Check if string is in a pandas dataframe

it seems that the OP meant to find out whether the string 'Mel' exists in a particular column, not contained in a column, therefore the use of contains is not needed, and is not efficient. A simple equals-to is enough:

(a['Names']=='Mel').any()

How do I get Month and Date of JavaScript in 2 digit format?

date-fns.

import { lightFormat } from 'date-fns';
lightFormat(new Date(), 'dd');

Interface naming in Java

I prefer not to use a prefix on interfaces:

  • The prefix hurts readability.

  • Using interfaces in clients is the standard best way to program, so interfaces names should be as short and pleasant as possible. Implementing classes should be uglier to discourage their use.

  • When changing from an abstract class to an interface a coding convention with prefix I implies renaming all the occurrences of the class --- not good!

how to do "press enter to exit" in batch

Use this snippet:

@echo off
echo something
echo.
echo press enter to exit
pause >nul
exit

Update an outdated branch against master in a Git repo

Update the master branch, which you need to do regardless.

Then, one of:

  1. Rebase the old branch against the master branch. Solve the merge conflicts during rebase, and the result will be an up-to-date branch that merges cleanly against master.

  2. Merge your branch into master, and resolve the merge conflicts.

  3. Merge master into your branch, and resolve the merge conflicts. Then, merging from your branch into master should be clean.

None of these is better than the other, they just have different trade-off patterns.

I would use the rebase approach, which gives cleaner overall results to later readers, in my opinion, but that is nothing aside from personal taste.

To rebase and keep the branch you would:

git checkout <branch> && git rebase <target>

In your case, check out the old branch, then

git rebase master 

to get it rebuilt against master.

Sum a list of numbers in Python

In the spirit of itertools. Inspiration from the pairwise recipe.

from itertools import tee, izip

def average(iterable):
    "s -> (s0,s1)/2.0, (s1,s2)/2.0, ..."
    a, b = tee(iterable)
    next(b, None)
    return ((x+y)/2.0 for x, y in izip(a, b))

Examples:

>>>list(average([1,2,3,4,5]))
[1.5, 2.5, 3.5, 4.5]
>>>list(average([1,20,31,45,56,0,0]))
[10.5, 25.5, 38.0, 50.5, 28.0, 0.0]
>>>list(average(average([1,2,3,4,5])))
[2.0, 3.0, 4.0]

String to LocalDate

Datetime formatting is performed by the org.joda.time.format.DateTimeFormatter class. Three classes provide factory methods to create formatters, and this is one. The others are ISODateTimeFormat and DateTimeFormatterBuilder.

DateTimeFormatter format = DateTimeFormat.forPattern("yyyy-MMM-dd");
LocalDate lDate = new LocalDate().parse("2005-nov-12",format);

final org.joda.time.LocalDate class is an immutable datetime class representing a date without a time zone. LocalDate is thread-safe and immutable, provided that the Chronology is as well. All standard Chronology classes supplied are thread-safe and immutable.

Is there "\n" equivalent in VBscript?

I think it's vbcrlf.

replace(s, vbcrlf, "<br />")

Limit Decimal Places in Android EditText

More elegant way would be using a regular expression ( regex ) as follows:

public class DecimalDigitsInputFilter implements InputFilter {

Pattern mPattern;

public DecimalDigitsInputFilter(int digitsBeforeZero,int digitsAfterZero) {
    mPattern=Pattern.compile("[0-9]{0," + (digitsBeforeZero-1) + "}+((\\.[0-9]{0," + (digitsAfterZero-1) + "})?)||(\\.)?");
}

@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {

        Matcher matcher=mPattern.matcher(dest);       
        if(!matcher.matches())
            return "";
        return null;
    }

}

To use it do:

editText.setFilters(new InputFilter[] {new DecimalDigitsInputFilter(5,2)});

How can I upload fresh code at github?

In Linux use below command to upload code in git
1 ) git clone repository
ask for user name and password.
2) got to respositiory directory.
3) git add project name.
4) git commit -m ' messgage '.
5) git push origin master.
- user name ,password

Update new Change code into Github

->Goto Directory That your github up code
->git commit ProjectName -m 'Message'
->git push origin master.

How to delete all files and folders in a directory?

The following example shows how you can do that. It first creates some directories and a file and then removes them via Directory.Delete(topPath, true);:

    static void Main(string[] args)
    {
        string topPath = @"C:\NewDirectory";
        string subPath = @"C:\NewDirectory\NewSubDirectory";

        try
        {
            Directory.CreateDirectory(subPath);

            using (StreamWriter writer = File.CreateText(subPath + @"\example.txt"))
            {
                writer.WriteLine("content added");
            }

            Directory.Delete(topPath, true);

            bool directoryExists = Directory.Exists(topPath);

            Console.WriteLine("top-level directory exists: " + directoryExists);
        }
        catch (Exception e)
        {
            Console.WriteLine("The process failed: {0}", e.Message);
        }
    }

It is taken from https://msdn.microsoft.com/en-us/library/fxeahc5f(v=vs.110).aspx.

Usage of the backtick character (`) in JavaScript

Apart from string interpolation, you can also call a function using back-tick.


var sayHello = function () {
    console.log('Hello', arguments);
}

// To call this function using ``

sayHello`some args`; // Check console for the output

// Or
sayHello`
    some args
`;

Check styled component. They use it heavily.

Insert new column into table in sqlite?

You can add new column with the query

ALTER TABLE TableName ADD COLUMN COLNew CHAR(25)

But it will be added at the end, not in between the existing columns.

How to use icons and symbols from "Font Awesome" on Native Android Application

In case you only need a few font awesome icons, you can also use http://fa2png.io to generate normal pixel images. But if you add new icons/buttons regularly I'd recommend the .ttf version as its more flexible.

Placeholder in UITextView

Another solution

import UIKit

protocol PlaceholderTextViewDelegate: class {

    func placeholderTextViewDidChangeText(_ text: String)
    func placeholderTextViewDidEndEditing(_ text: String)
}

final class PlaceholderTextView: UITextView {

    weak var notifier: PlaceholderTextViewDelegate?
    var ignoreEnterAction: Bool = true

    var placeholder: String? {
        didSet {
            text = placeholder
            selectedRange = NSRange(location: 0, length: 0)
        }
    }

    var placeholderColor = UIColor.lightGray {
        didSet {
            if text == placeholder {
                textColor = placeholderColor
            }
        }
    }
    var normalTextColor = UIColor.lightGray

    var placeholderFont = UIFont.sfProRegular(28)

    fileprivate var placeholderLabel: UILabel?

    // MARK: - LifeCycle

    override var text: String? {
        didSet {
            if text == placeholder {
                textColor = placeholderColor
            } else {
                textColor = normalTextColor
            }
        }
    }

    init() {
        super.init(frame: CGRect.zero, textContainer: nil)
        awakeFromNib()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func awakeFromNib() {
        super.awakeFromNib()

        self.delegate = self
    }
}

extension PlaceholderTextView: UITextViewDelegate {

    // MARK: - UITextViewDelegate
    func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {

        if text == "" && textView.text == placeholder {
            return false
        }

        if let placeholder = placeholder,
            textView.text == placeholder,
            range.location <= placeholder.count {
            textView.text = ""
        }

        if ignoreEnterAction && text == "\n" {
            textView.resignFirstResponder()
            return false
        }
        return true
    }

    func textViewDidChange(_ textView: UITextView) {
        if let placeholder = placeholder {
            textView.text = textView.text.replacingOccurrences(of: placeholder, with: "")
        }

        if let placeholder = placeholder,
            text?.isEmpty == true {
            text = placeholder
            textColor = placeholderColor

            selectedRange = NSRange(location: 0, length: 0)
        } else {
            textColor = normalTextColor
        }

        notifier?.placeholderTextViewDidChangeText(textView.text)
    }

    func textViewDidChangeSelection(_ textView: UITextView) {
        if let placeholder = placeholder,
            text == placeholder {
            selectedRange = NSRange(location: 0, length: 0)
        }
    }

    func textViewDidEndEditing(_ textView: UITextView) {
        notifier?.placeholderTextViewDidEndEditing(textView.text)

        if let placeholder = placeholder,
            text?.isEmpty == true {
            text = placeholder
            textColor = placeholderColor
            selectedRange = NSRange(location: 0, length: 0)
        } else {
            textColor = normalTextColor
        }
    }
}

result:

enter image description here

Count(*) vs Count(1) - SQL Server

COUNT(*) and COUNT(1) are same in case of result and performance.

Submit form using a button outside the <form> tag

In HTML5, there is the form attribute. Basically

<form id="myform" method="get" action="something.php">
    <input type="text" name="name" />
</form>

<input type="submit" form="myform" />

How to remove extension from string (only real extension!)

Use this:

strstr('filename.ext','.',true);
//result filename

Python UTC datetime object's ISO format doesn't include Z (Zulu or Zero offset)

Python datetime objects don't have time zone info by default, and without it, Python actually violates the ISO 8601 specification (if no time zone info is given, assumed to be local time). You can use the pytz package to get some default time zones, or directly subclass tzinfo yourself:

from datetime import datetime, tzinfo, timedelta
class simple_utc(tzinfo):
    def tzname(self,**kwargs):
        return "UTC"
    def utcoffset(self, dt):
        return timedelta(0)

Then you can manually add the time zone info to utcnow():

>>> datetime.utcnow().replace(tzinfo=simple_utc()).isoformat()
'2014-05-16T22:51:53.015001+00:00'

Note that this DOES conform to the ISO 8601 format, which allows for either Z or +00:00 as the suffix for UTC. Note that the latter actually conforms to the standard better, with how time zones are represented in general (UTC is a special case.)

How to Find the Default Charset/Encoding in Java?

First, Latin-1 is the same as ISO-8859-1, so, the default was already OK for you. Right?

You successfully set the encoding to ISO-8859-1 with your command line parameter. You also set it programmatically to "Latin-1", but, that's not a recognized value of a file encoding for Java. See http://java.sun.com/javase/6/docs/technotes/guides/intl/encoding.doc.html

When you do that, looks like Charset resets to UTF-8, from looking at the source. That at least explains most of the behavior.

I don't know why OutputStreamWriter shows ISO8859_1. It delegates to closed-source sun.misc.* classes. I'm guessing it isn't quite dealing with encoding via the same mechanism, which is weird.

But of course you should always be specifying what encoding you mean in this code. I'd never rely on the platform default.

Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server."

For those using the internal IIS of Visual Studio, try the following:

  1. Generate the error message.
  2. Break the debugger at the error display.
  3. Check the callstack. You should see 'raise'.
  4. Double click 'raise'.
  5. Check the internals of 'sender' parameter. You will see a '_xmlHttpRequest' property.
  6. Open the '_xmlHttpRequest' property, and you'll see a 'response' property.
  7. The 'response' property will have the actual message.

I hope this helps someone out there!

close fxml window by code, javafx

Hide doesn't close the window, just put in visible mode. The best solution was:

@FXML
private void exitButtonOnAction(ActionEvent event){
        ((Stage)(((Button)event.getSource()).getScene().getWindow())).close();      
}

How to create a .gitignore file

The .gitignore file is not added to a repository by default. Use vi or your favorite text editor to create the .gitignore file then issue a git add .gitignore followed by git commit -m "message" .gitignore. The following commands will take care of it.

> .gitignore
git add .gitignore
git commit -m "message" .gitignore

Extract text from a string

Using -replace

 $string = '% O0033(SUB RAD MSD 50R III) G91G1X-6.4Z-2.F500 G3I6.4Z-8.G3I6.4 G3R3.2X6.4F500 G91G0Z5. G91G1X-10.4 G3I10.4 G3R5.2X10.4 G90G0Z2. M99 %'
 $program = $string -replace '^%\sO\d{4}\((.+?)\).+$','$1'
 $program

SUB RAD MSD 50R III

How do I sort a two-dimensional (rectangular) array in C#?

This is an old question, but here's a class I just built based on the article from Jim Mischel at InformIt linked by Doug L.

class Array2DSort : IComparer<int>
{
    // maintain a reference to the 2-dimensional array being sorted
    string[,] _sortArray;
    int[] _tagArray;
    int _sortIndex;

    protected string[,] SortArray { get { return _sortArray; } }

    // constructor initializes the sortArray reference
    public Array2DSort(string[,] theArray, int sortIndex)
    {
        _sortArray = theArray;
        _tagArray = new int[_sortArray.GetLength(0)];
        for (int i = 0; i < _sortArray.GetLength(0); ++i) _tagArray[i] = i;
        _sortIndex = sortIndex;
    }

    public string[,] ToSortedArray()
    {
        Array.Sort(_tagArray, this);
        string[,] result = new string[
            _sortArray.GetLength(0), _sortArray.GetLength(1)];
        for (int i = 0; i < _sortArray.GetLength(0); i++)
        {
            for (int j = 0; j < _sortArray.GetLength(1); j++)
            {
                result[i, j] = _sortArray[_tagArray[i], j];
            }
        }
        return result;
    }

    // x and y are integer row numbers into the sortArray
    public virtual int Compare(int x, int y)
    {
        if (_sortIndex < 0) return 0;
        return CompareStrings(x, y, _sortIndex);
    }

    protected int CompareStrings(int x, int y, int col)
    {
        return _sortArray[x, col].CompareTo(_sortArray[y, col]);
    }
}

Given an unsorted 2D array data of arbitrary size that you want to sort on column 5 you just do this:

        Array2DSort comparer = new Array2DSort(data, 5);
        string[,] sortedData = comparer.ToSortedArray();

Note the virtual Compare method and protected SortArray so you can create specialized subclasses that always sort on a particular column or do specialized sorting on multiple columns or whatever you want to do. That's also why CompareStrings is broken out and protected - any subclasses can use it for simple comparisons instead of typing out the full SortArray[x, col].CompareTo(SortArray[y, col]) syntax.

Why do I have ORA-00904 even when the column is present?

check the position of Column annotation in java class for the field For Example,consider one table with name STUDENT with 3 column(Name,Roll_No,Marks).

Then make sure you have added below annotation of column before Getter Method instead of Setter method. It will solve ur problem @Column(name = "Name", length = 100)

**@Column(name = "NAME", length = 100)
public String getName() {**
    return name;
}

    public void setName(String name) {
    this.name= name;
}

How to extract or unpack an .ab file (Android Backup file)

I have had to unpack a .ab-file, too and found this post while looking for an answer. My suggested solution is Android Backup Extractor, a free Java tool for Windows, Linux and Mac OS.

Make sure to take a look at the README, if you encounter a problem. You might have to download further files, if your .ab-file is password-protected.

Usage:
java -jar abe.jar [-debug] [-useenv=yourenv] unpack <backup.ab> <backup.tar> [password]

Example:

Let's say, you've got a file test.ab, which is not password-protected, you're using Windows and want the resulting .tar-Archive to be called test.tar. Then your command should be:

java.exe -jar abe.jar unpack test.ab test.tar ""

Get the Highlighted/Selected text

This solution works if you're using chrome (can't verify other browsers) and if the text is located in the same DOM Element:

window.getSelection().anchorNode.textContent.substring(
  window.getSelection().extentOffset, 
  window.getSelection().anchorOffset)

Could not install packages due to an EnvironmentError: [Errno 13]

I already tried all suggestion posted in here, yet I'm still getting the errno 13,

I'm using Windows and my python version is 3.7.3

After 5 hours of trying to solve it, this step worked for me:

I try to open the command prompt by run as administrator

Query for array elements inside JSON type

jsonb in Postgres 9.4+

You can use the same query as below, just with jsonb_array_elements().

But rather use the jsonb "contains" operator @> in combination with a matching GIN index on the expression data->'objects':

CREATE INDEX reports_data_gin_idx ON reports
USING gin ((data->'objects') jsonb_path_ops);

SELECT * FROM reports WHERE data->'objects' @> '[{"src":"foo.png"}]';

Since the key objects holds a JSON array, we need to match the structure in the search term and wrap the array element into square brackets, too. Drop the array brackets when searching a plain record.

More explanation and options:

json in Postgres 9.3+

Unnest the JSON array with the function json_array_elements() in a lateral join in the FROM clause and test for its elements:

SELECT data::text, obj
FROM   reports r, json_array_elements(r.data#>'{objects}') obj
WHERE  obj->>'src' = 'foo.png';

db<>fiddle here
Old sqlfiddle

The CTE (WITH query) just substitutes for a table reports.
Or, equivalent for just a single level of nesting:

SELECT *
FROM   reports r, json_array_elements(r.data->'objects') obj
WHERE  obj->>'src' = 'foo.png';

->>, -> and #> operators are explained in the manual.

Both queries use an implicit JOIN LATERAL.

Closely related:

Bigger Glyphicons

If you are using bootstrap 3, use tag, like this <small><span class="glyphicon glyphicon-send"></span></small> It works perfect for Bootstrap 3.
You can even use multiple <small> tags to set the size more smaller.
Code:
<small><small><span class="glyphicon glyphicon-send"></span></small></small>

Node.js global proxy setting

replace {userid} and {password} with your id and password in your organization or login to your machine.

npm config set proxy http://{userid}:{password}@proxyip:8080/
npm config set https-proxy http://{userid}:{password}@proxyip:8080/
npm config set http-proxy http://{userid}:{password}@proxyip:8080/
strict-ssl=false

Android Studio Rendering Problems : The following classes could not be found

To use the class ActionBarOverlayLayout you need to include this in the dependencies section of build.gradle file:

compile 'com.android.support:design:24.1.1'

Sync the project once again and then you will find no problem

Python: Figure out local timezone

Based on Thoku's answer above, here's an answer that resolves the time zone to the nearest half hour (which is relevant for some timezones eg South Australia's) :

from datetime import datetime
round((round((datetime.now()-datetime.utcnow()).total_seconds())/1800)/2)

How do I encrypt and decrypt a string in python?

Encrypt Data

First, we need to install the cryptography library:

pip3 install cryptography
  • From the cryptography library, we need to import Fernet and start generating a key - this key is required for symmetric encryption/decryption.

  • To generate a key, we call the generate_key() method.

    • We only need to execute the above method once to generate a key.

    You need to keep this key in a safe place. If you lose the key, you won't be able to decrypt the data that was encrypted with this key.

  • Once we have generated a key, we need to load the key with load_key()

Encrypt a Message

This is a three step process:

  1. encode the message
  2. initialize the Fernet class
  3. pass the encoded message to encrypt() method

Below is a full working example of encrypting a message :

from cryptography.fernet import Fernet

def generate_key():
    """
    Generates a key and save it into a file
    """
    key = Fernet.generate_key()
    with open("secret.key", "wb") as key_file:
        key_file.write(key)

def load_key():
    """
    Load the previously generated key
    """
    return open("secret.key", "rb").read()

def encrypt_message(message):
    """
    Encrypts a message
    """
    key = load_key()
    encoded_message = message.encode()
    f = Fernet(key)
    encrypted_message = f.encrypt(encoded_message)

    print(encrypted_message)

if __name__ == "__main__":
    # generate_key() # execute only once 
    encrypt_message("Hello stackoverflow!")

output:

b'gAAAAABgLX7Zj-kn-We2BI_c9NQhEtfJEnHUVhVqtiqjkDi5dgJafj-_8QUDyeNS2zsJTdBWg6SntRJOjOM1U5mIxxsGny7IEGqpVVdHwheTnwzSBlgpb80='

Decrypt Data

To decrypt the message, we just call the decrypt() method from the Fernet library. Remember, we also need to load the key as well, because the key is needed to decrypt the message.

from cryptography.fernet import Fernet

def load_key():
    """
    Load the previously generated key
    """
    return open("secret.key", "rb").read()

def decrypt_message(encrypted_message):
    """
    Decrypts an encrypted message
    """
    key = load_key()
    f = Fernet(key)
    decrypted_message = f.decrypt(encrypted_message)

    print(decrypted_message.decode())

if __name__ == "__main__":
    decrypt_message(b'gAAAAABgLX7Zj-kn-We2BI_c9NQhEtfJEnHUVhVqtiqjkDi5dgJafj-_8QUDyeNS2zsJTdBWg6SntRJOjOM1U5mIxxsGny7IEGqpVVdHwheTnwzSBlgpb80=')

output:

Hello stackoverflow!


Your password is in the secret.key in a form similar to the password below:

B8wtXqwBA_zb2Iaz5pW8CIQIwGSYSFoBiLsVz-vTqzw=

How to save username and password in Git?

For windows users look at the .gitconfig file and check what has been configured for the credential helper if you have the following...

[credential "helperselector"] selected = wincred

you'll find the credentials in the Windows Credential Manager.

enter image description here

There you can edit the credential.

EDIT: Wincred has been deprecated, see...

https://github.com/git-for-windows/git-sdk-64/tree/main/mingw64/doc/git-credential-manager

So alternatively you may want to reconfigure git to use the built-in GIT credential manager...

git config --global credential.helper manager

Apply function to each column in a data frame observing each columns existing data type

df <- head(mtcars)
df$string <- c("a","b", "c", "d","e", "f"); df

my.min <- unlist(lapply(df, min))
my.max <- unlist(lapply(df, max))