Programs & Examples On #Dlna

Digital Living Network Alliance (DLNA) creates guidelines for interoperability of multimedia devices.

Why is the minidlna database not being refreshed?

Resolved with crontab root

10 * * * * /usr/bin/minidlnad -r

MySQL does not start when upgrading OSX to Yosemite or El Capitan

You just need to create the user mysql (mysql installation script creates _mysql)

sudo vipw

duplicate line that contains _mysql

Change for the duplicated line _mysql to mysql

sudo /usr/local/mysql/support-files/mysql.server start
Starting MySQL
.. SUCCESS!

How do I show the number keyboard on an EditText in android?

editText.setRawInputType(InputType.TYPE_CLASS_NUMBER);

How to get base url with jquery or javascript?

This is an extremely old question, but here are the approaches I personally use ...

Get Standard/Base URL

As many have already stated, this works for most situations.

var url = window.location.origin;


Get Absolute Base URL

However, this simple approach can be used to strip off any port numbers.

var url = "http://" + location.host.split(":")[0];

Edit: To address the concern, posed by Jason Rice, the following can be used to automatically insert the correct protocol type ...

var url = window.location.protocol + "//" + location.host.split(":")[0];


Set Base URL

As a bonus -- the base URL can then be redefined globally.

document.head.innerHTML = document.head.innerHTML + "<base href='" + url + "' />";

Return HTTP status code 201 in flask

In your flask code, you should ideally specify the MIME type as often as possible, as well:

return html_page_str, 200, {'ContentType':'text/html'}

return json.dumps({'success':True}), 200, {'ContentType':'application/json'}

...etc

Failed to load resource: the server responded with a status of 404 (Not Found) error in server

By default, IUSR account is used for anonymous user.

All you need to do is:

IIS -> Authentication --> Set Anonymous Authentication to Application Pool Identity.

Problem solved :)

fatal: Unable to create temporary file '/home/username/git/myrepo.git/./objects/pack/tmp_pack_XXXXXX': Permission denied

One of the principal issues with pushing to a GIT is that the material you push will appear as your material, and will block submissions from other people on a team. As a GIT repository administrator, you will have to manage the hooks to prevent Alice's push from blocking Bob from pushing. To do that, you will want to ensure that your developers all belong to a group, lets call it 'developers' and that the repository is owned by root:developers, and then add this to the hooks/post-update script:

sudo chown -R root:developers $GIT_DIR
sudo chmod -R g+w $GIT_DIR

That will make it so that team members are able to push to the repository without stepping on each other's toes.

How to upload a file from Windows machine to Linux machine using command lines via PuTTy?

Use putty. Put install directory path in environment values (PATH), and restart your PC if required.

Open cmd (command prompt) and type

C:/> pscp "C:\Users/gsjha/Desktop/example.txt" user@host:/home/

It'll be copied to the system.

Android EditText delete(backspace) key event

My simple solution which works perfectly. You should to add a flag. My code snippet:

editText.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            if (after < count) {
                isBackspaceClicked = true;
            } else {
                isBackspaceClicked = false;
            }
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) { }

        @Override
        public void afterTextChanged(Editable s) {
            if (!isBackspaceClicked) {
                // Your current code
            } else {
                // Your "backspace" handling
            }
        }

What is the incentive for curl to release the library for free?

I'm Daniel Stenberg.

I made curl

I founded the curl project back in 1998, I wrote the initial curl version and I created libcurl. I've written more than half of all the 24,000 commits done in the source code repository up to this point in time. I'm still the lead developer of the project. To a large extent, curl is my baby.

I shipped the first version of curl as open source since I wanted to "give back" to the open source world that had given me so much code already. I had used so much open source and I wanted to be as cool as the other open source authors.

Thanks to it being open source, literally thousands of people have been able to help us out over the years and have improved the products, the documentation. the web site and just about every other detail around the project. curl and libcurl would never have become the products that they are today were they not open source. The list of contributors now surpass 1900 names and currently the list grows with a few hundred names per year.

Thanks to curl and libcurl being open source and liberally licensed, they were immediately adopted in numerous products and soon shipped by operating systems and Linux distributions everywhere thus getting a reach beyond imagination.

Thanks to them being "everywhere", available and liberally licensed they got adopted and used everywhere and by everyone. It created a defacto transfer library standard.

At an estimated six billion installations world wide, we can safely say that curl is the most widely used internet transfer library in the world. It simply would not have gone there had it not been open source. curl runs in billions of mobile phones, a billion Windows 10 installations, in a half a billion games and several hundred million TVs - and more.

Should I have released it with proprietary license instead and charged users for it? It never occured to me, and it wouldn't have worked because I would never had managed to create this kind of stellar project on my own. And projects and companies wouldn't have used it.

Why do I still work on curl?

Now, why do I and my fellow curl developers still continue to develop curl and give it away for free to the world?

  1. I can't speak for my fellow project team members. We all participate in this for our own reasons.
  2. I think it's still the right thing to do. I'm proud of what we've accomplished and I truly want to make the world a better place and I think curl does its little part in this.
  3. There are still bugs to fix and features to add!
  4. curl is free but my time is not. I still have a job and someone still has to pay someone for me to get paid every month so that I can put food on the table for my family. I charge customers and companies to help them with curl. You too can get my help for a fee, which then indirectly helps making sure that curl continues to evolve, remain free and the kick-ass product it is.
  5. curl was my spare time project for twenty years before I started working with it full time. I've had great jobs and worked on awesome projects. I've been in a position of luxury where I could continue to work on curl on my spare time and keep shipping a quality product for free. My work on curl has given me friends, boosted my career and taken me to places I would not have been at otherwise.
  6. I would not do it differently if I could back and do it again.

Am I proud of what we've done?

Yes. So insanely much.

But I'm not satisfied with this and I'm not just leaning back, happy with what we've done. I keep working on curl every single day, to improve, to fix bugs, to add features and to make sure curl keeps being the number one file transfer solution for the world even going forward.

We do mistakes along the way. We make the wrong decisions and sometimes we implement things in crazy ways. But to win in the end and to conquer the world is about patience and endurance and constantly going back and reconsidering previous decisions and correcting previous mistakes. To continuously iterate, polish off rough edges and gradually improve over time.

Never give in. Never stop. Fix bugs. Add features. Iterate. To the end of time.

For real?

Yeah. For real.

Do I ever get tired? Is it ever done?

Sure I get tired at times. Working on something every day for over twenty years isn't a paved downhill road. Sometimes there are obstacles. During times things are rough. Occasionally people are just as ugly and annoying as people can be.

But curl is my life's project and I have patience. I have thick skin and I don't give up easily. The tough times pass and most days are awesome. I get to hang out with awesome people and the reward is knowing that my code helps driving the Internet revolution everywhere is an ego boost above normal.

curl will never be "done" and so far I think work on curl is pretty much the most fun I can imagine. Yes, I still think so even after twenty years in the driver's seat. And as long as I think it's fun I intend to keep at it.

How do I create a ListView with rounded corners in Android?

Yet another solution to selection highlight problems with first, and last items in the list:

Add padding to the top and bottom of your list background equal to or greater than the radius. This ensures the selection highlighting doesn't overlap with your corner curves.

This is the easiest solution when you need non-transparent selection highlighting.

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
    <solid android:color="@color/listbg" />
    <stroke
        android:width="2dip"
        android:color="#D5D5D5" />
    <corners android:radius="10dip" />

    <!-- Make sure bottom and top padding match corner radius -->
    <padding
        android:bottom="10dip"
        android:left="2dip"
        android:right="2dip"
        android:top="10dip" />
</shape>

git cherry-pick says "...38c74d is a merge but no -m option was given"

@Borealid's answer is correct, but suppose that you don't care about preserving the exact merging history of a branch and just want to cherry-pick a linearized version of it. Here's an easy and safe way to do that:

Starting state: you are on branch X, and you want to cherry-pick the commits Y..Z.

  1. git checkout -b tempZ Z
  2. git rebase Y
  3. git checkout -b newX X
  4. git cherry-pick Y..tempZ
  5. (optional) git branch -D tempZ

What this does is to create a branch tempZ based on Z, but with the history from Y onward linearized, and then cherry-pick that onto a copy of X called newX. (It's safer to do this on a new branch rather than to mutate X.) Of course there might be conflicts in step 4, which you'll have to resolve in the usual way (cherry-pick works very much like rebase in that respect). Finally it deletes the temporary tempZ branch.

If step 2 gives the message "Current branch tempZ is up to date", then Y..Z was already linear, so just ignore that message and proceed with steps 3 onward.

Then review newX and see whether that did what you wanted.

(Note: this is not the same as a simple git rebase X when on branch Z, because it doesn't depend in any way on the relationship between X and Y; there may be commits between the common ancestor and Y that you didn't want.)

Assert a function/method was not called using Mock

Judging from other answers, no one except @rob-kennedy talked about the call_args_list.

It's a powerful tool for that you can implement the exact contrary of MagicMock.assert_called_with()

call_args_list is a list of call objects. Each call object represents a call made on a mocked callable.

>>> from unittest.mock import MagicMock
>>> m = MagicMock()
>>> m.call_args_list
[]
>>> m(42)
<MagicMock name='mock()' id='139675158423872'>
>>> m.call_args_list
[call(42)]
>>> m(42, 30)
<MagicMock name='mock()' id='139675158423872'>
>>> m.call_args_list
[call(42), call(42, 30)]

Consuming a call object is easy, since you can compare it with a tuple of length 2 where the first component is a tuple containing all the positional arguments of the related call, while the second component is a dictionary of the keyword arguments.

>>> ((42,),) in m.call_args_list
True
>>> m(42, foo='bar')
<MagicMock name='mock()' id='139675158423872'>
>>> ((42,), {'foo': 'bar'}) in m.call_args_list
True
>>> m(foo='bar')
<MagicMock name='mock()' id='139675158423872'>
>>> ((), {'foo': 'bar'}) in m.call_args_list
True

So, a way to address the specific problem of the OP is

def test_something():
    with patch('something') as my_var:
        assert ((some, args),) not in my_var.call_args_list

Note that this way, instead of just checking if a mocked callable has been called, via MagicMock.called, you can now check if it has been called with a specific set of arguments.

That's useful. Say you want to test a function that takes a list and call another function, compute(), for each of the value of the list only if they satisfy a specific condition.

You can now mock compute, and test if it has been called on some value but not on others.

Python strip() multiple characters?

I did a time test here, using each method 100000 times in a loop. The results surprised me. (The results still surprise me after editing them in response to valid criticism in the comments.)

Here's the script:

import timeit

bad_chars = '(){}<>'

setup = """import re
import string
s = 'Barack (of Washington)'
bad_chars = '(){}<>'
rgx = re.compile('[%s]' % bad_chars)"""

timer = timeit.Timer('o = "".join(c for c in s if c not in bad_chars)', setup=setup)
print "List comprehension: ",  timer.timeit(100000)


timer = timeit.Timer("o= rgx.sub('', s)", setup=setup)
print "Regular expression: ", timer.timeit(100000)

timer = timeit.Timer('for c in bad_chars: s = s.replace(c, "")', setup=setup)
print "Replace in loop: ", timer.timeit(100000)

timer = timeit.Timer('s.translate(string.maketrans("", "", ), bad_chars)', setup=setup)
print "string.translate: ", timer.timeit(100000)

Here are the results:

List comprehension:  0.631745100021
Regular expression:  0.155561923981
Replace in loop:  0.235936164856
string.translate:  0.0965719223022

Results on other runs follow a similar pattern. If speed is not the primary concern, however, I still think string.translate is not the most readable; the other three are more obvious, though slower to varying degrees.

How to hide element label by element id in CSS?

Despite other answers here, you should not use display:none to hide the label element.

The accessible way to hide a label visually is to use an 'off-left' or 'clip' rule in your CSS. Using display:none will prevent people who use screen-readers from having access to the content of the label element. Using display:none hides content from all users, and that includes screen-reader users (who benefit most from label elements).

label[for="foo"] { 
    border: 0;
    clip: rect(0 0 0 0);
    height: 1px;
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    width: 1px;
}

The W3C and WAI offer more guidance on this topic, including CSS for the 'clip' technique.

Virtual Serial Port for Linux

You may want to look at Tibbo VSPDL for creating a linux virtual serial port using a Kernel driver -- it seems pretty new, and is available for download right now (beta version). Not sure about the license at this point, or whether they want to make it available commercially only in the future.

There are other commercial alternatives, such as http://www.ttyredirector.com/.

In Open Source, Remserial (GPL) may also do what you want, using Unix PTY's. It transmits the serial data in "raw form" to a network socket; STTY-like setup of terminal parameters must be done when creating the port, changing them later like described in RFC 2217 does not seem to be supported. You should be able to run two remserial instances to create a virtual nullmodem like com0com, except that you'll need to set up port speed etc in advance.

Socat (also GPL) is like an extended variant of Remserial with many many more options, including a "PTY" method for redirecting the PTY to something else, which can be another instance of Socat. For Unit tets, socat is likely nicer than remserial because you can directly cat files into the PTY. See the PTY example on the manpage. A patch exists under "contrib" to provide RFC2217 support for negotiating serial line settings.

Execute SQL script from command line

If you use Integrated Security, you might want to know that you simply need to use -E like this:

sqlcmd -S Serverinstance -E -i import_file.sql

Converting dict to OrderedDict

You are creating a dictionary first, then passing that dictionary to an OrderedDict. For Python versions < 3.6 (*), by the time you do that, the ordering is no longer going to be correct. dict is inherently not ordered.

Pass in a sequence of tuples instead:

ship = [("NAME", "Albatross"),
        ("HP", 50),
        ("BLASTERS", 13),
        ("THRUSTERS", 18),
        ("PRICE", 250)]
ship = collections.OrderedDict(ship)

What you see when you print the OrderedDict is it's representation, and it is entirely correct. OrderedDict([('PRICE', 250), ('HP', 50), ('NAME', 'Albatross'), ('BLASTERS', 13), ('THRUSTERS', 18)]) just shows you, in a reproducable representation, what the contents are of the OrderedDict.


(*): In the CPython 3.6 implementation, the dict type was updated to use a more memory efficient internal structure that has the happy side effect of preserving insertion order, and by extension the code shown in the question works without issues. As of Python 3.7, the Python language specification has been updated to require that all Python implementations must follow this behaviour. See this other answer of mine for details and also why you'd still may want to use an OrderedDict() for certain cases.

Intercept a form submit in JavaScript and prevent normal submission

You cannot attach events before the elements you attach them to has loaded

This works -

Plain JS

DEMO

Recommended to use eventListener

_x000D_
_x000D_
// Should only be triggered on first page load
console.log('ho');

window.addEventListener("load", function() {
  document.getElementById('my-form').addEventListener("submit", function(e) {
    e.preventDefault(); // before the code
    /* do what you want with the form */

    // Should be triggered on form submit
    console.log('hi');
  })
});
_x000D_
<form id="my-form">
  <input type="text" name="in" value="some data" />
  <button type="submit">Go</button>
</form>
_x000D_
_x000D_
_x000D_

but if you do not need more than one listener you can use onload and onsubmit

_x000D_
_x000D_
// Should only be triggered on first page load
console.log('ho');

window.onload = function() {
  document.getElementById('my-form').onsubmit = function() {
    /* do what you want with the form */

    // Should be triggered on form submit
    console.log('hi');
    // You must return false to prevent the default form behavior
    return false;
  }
}
_x000D_
    <form id="my-form">
      <input type="text" name="in" value="some data" />
      <button type="submit">Go</button>
    </form>
_x000D_
_x000D_
_x000D_

jQuery

_x000D_
_x000D_
// Should only be triggered on first page load
console.log('ho');

$(function() {
  $('#my-form').on("submit", function(e) {
    e.preventDefault(); // cancel the actual submit

    /* do what you want with the form */

    // Should be triggered on form submit

    console.log('hi');
  });
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form id="my-form">
  <input type="text" name="in" value="some data" />
  <button type="submit">Go</button>
</form>
_x000D_
_x000D_
_x000D_

How can you dynamically create variables via a while loop?

For free-dom:

import random

alphabet = tuple('abcdefghijklmnopqrstuvwxyz')

globkeys = globals().keys()
globkeys.append('globkeys') # because name 'globkeys' is now also in globals()

print 'globkeys==',globkeys
print
print "globals().keys()==",globals().keys()

for i in xrange(8):
    globals()[''.join(random.sample(alphabet,random.randint(3,26)))] = random.choice(alphabet)
del i

newnames = [ x for x in globals().keys() if x not in globkeys ]
print
print 'newnames==',newnames

print
print "globals().keys()==",globals().keys()

print
print '\n'.join(repr((u,globals()[u])) for u in newnames)

Result

globkeys== ['__builtins__', 'alphabet', 'random', '__package__', '__name__', '__doc__', 'globkeys']

globals().keys()== ['__builtins__', 'alphabet', 'random', '__package__', '__name__', 'globkeys', '__doc__']

newnames== ['fztkebyrdwcigsmulnoaph', 'umkfcvztleoij', 'kbutmzfgpcdqanrivwsxly', 'lxzmaysuornvdpjqfetbchgik', 'wznptbyermclfdghqxjvki', 'lwg', 'vsolxgkz', 'yobtlkqh']

globals().keys()== ['fztkebyrdwcigsmulnoaph', 'umkfcvztleoij', 'newnames', 'kbutmzfgpcdqanrivwsxly', '__builtins__', 'alphabet', 'random', 'lxzmaysuornvdpjqfetbchgik', '__package__', 'wznptbyermclfdghqxjvki', 'lwg', 'x', 'vsolxgkz', '__name__', 'globkeys', '__doc__', 'yobtlkqh']

('fztkebyrdwcigsmulnoaph', 't')
('umkfcvztleoij', 'p')
('kbutmzfgpcdqanrivwsxly', 'a')
('lxzmaysuornvdpjqfetbchgik', 'n')
('wznptbyermclfdghqxjvki', 't')
('lwg', 'j')
('vsolxgkz', 'w')
('yobtlkqh', 'c')

Another way:

import random

pool_of_names = []
for i in xrange(1000):
    v = 'LXM'+str(random.randrange(10,100000))
    if v not in globals():
        pool_of_names.append(v)

alphabet = 'abcdefghijklmnopqrstuvwxyz' 

print 'globals().keys()==',globals().keys()

print
for j in xrange(8):
    globals()[pool_of_names[j]] = random.choice(alphabet)
newnames = pool_of_names[0:j+1]

print
print 'globals().keys()==',globals().keys()

print
print '\n'.join(repr((u,globals()[u])) for u in newnames)

result:

globals().keys()== ['__builtins__', 'alphabet', 'random', '__package__', 'i', 'v', '__name__', '__doc__', 'pool_of_names']


globals().keys()== ['LXM7646', 'random', 'newnames', 'LXM95826', 'pool_of_names', 'LXM66380', 'alphabet', 'LXM84070', '__package__', 'LXM8644', '__doc__', 'LXM33579', '__builtins__', '__name__', 'LXM58418', 'i', 'j', 'LXM24703', 'v']

('LXM66380', 'v')
('LXM7646', 'a')
('LXM8644', 'm')
('LXM24703', 'r')
('LXM58418', 'g')
('LXM84070', 'c')
('LXM95826', 'e')
('LXM33579', 'j')

What is the difference between & and && in Java?

it's as specified in the JLS (15.22.2):

When both operands of a &, ^, or | operator are of type boolean or Boolean, then the type of the bitwise operator expression is boolean. In all cases, the operands are subject to unboxing conversion (§5.1.8) as necessary.

For &, the result value is true if both operand values are true; otherwise, the result is false.

For ^, the result value is true if the operand values are different; otherwise, the result is false.

For |, the result value is false if both operand values are false; otherwise, the result is true.

The "trick" is that & is an Integer Bitwise Operator as well as an Boolean Logical Operator. So why not, seeing this as an example for operator overloading is reasonable.

Errors: "INSERT EXEC statement cannot be nested." and "Cannot use the ROLLBACK statement within an INSERT-EXEC statement." How to solve this?

what about just store the output to the static table ? Like

-- SubProcedure: subProcedureName
---------------------------------
-- Save the value
DELETE lastValue_subProcedureName
INSERT INTO lastValue_subProcedureName (Value)
SELECT @Value
-- Return the value
SELECT @Value

-- Procedure
--------------------------------------------
-- get last value of subProcedureName
SELECT Value FROM lastValue_subProcedureName

its not ideal, but its so simple and you don't need to rewrite everything.

UPDATE: the previous solution does not work well with parallel queries (async and multiuser accessing) therefore now Iam using temp tables

-- A local temporary table created in a stored procedure is dropped automatically when the stored procedure is finished. 
-- The table can be referenced by any nested stored procedures executed by the stored procedure that created the table. 
-- The table cannot be referenced by the process that called the stored procedure that created the table.
IF OBJECT_ID('tempdb..#lastValue_spGetData') IS NULL
CREATE TABLE #lastValue_spGetData (Value INT)

-- trigger stored procedure with special silent parameter
EXEC dbo.spGetData 1 --silent mode parameter

nested spGetData stored procedure content

-- Save the output if temporary table exists.
IF OBJECT_ID('tempdb..#lastValue_spGetData') IS NOT NULL
BEGIN
    DELETE #lastValue_spGetData
    INSERT INTO #lastValue_spGetData(Value)
    SELECT Col1 FROM dbo.Table1
END

 -- stored procedure return
 IF @silentMode = 0
 SELECT Col1 FROM dbo.Table1

sed command with -i option failing on Mac, but works on Linux

As the other answers indicate, there is not a way to use sed portably across OS X and Linux without making backup files. So, I instead used this Ruby one-liner to do so:

ruby -pi -e "sub(/ $/, '')" ./config/locales/*.yml

In my case, I needed to call it from a rake task (i.e., inside a Ruby script), so I used this additional level of quoting:

sh %q{ruby -pi -e "sub(/ $/, '')" ./config/locales/*.yml}

What is the advantage of using heredoc in PHP?

The heredoc syntax is much cleaner to me and it is really useful for multi-line strings and avoiding quoting issues. Back in the day I used to use them to construct SQL queries:

$sql = <<<SQL
select *
  from $tablename
 where id in [$order_ids_list]
   and product_name = "widgets"
SQL;

To me this has a lower probability of introducing a syntax error than using quotes:

$sql = "
select *
  from $tablename
 where id in [$order_ids_list]
   and product_name = \"widgets\"
";

Another point is to avoid escaping double quotes in your string:

$x = "The point of the \"argument" was to illustrate the use of here documents";

The problem with the above is the syntax error (the missing escaped quote) I just introduced as opposed to here document syntax:

$x = <<<EOF
The point of the "argument" was to illustrate the use of here documents
EOF;

It is a bit of style, but I use the following as rules for single, double and here documents for defining strings:

  • Single quotes are used when the string is a constant like 'no variables here'
  • Double quotes when I can put the string on a single line and require variable interpolation or an embedded single quote "Today is ${user}'s birthday"
  • Here documents for multi-line strings that require formatting and variable interpolation.

How do I make a Mac Terminal pop-up/alert? Applescript?

Use osascript. For example:

osascript -e 'tell app "Finder" to display dialog "Hello World"' 

Replacing “Finder” with whatever app you desire. Note if that app is backgrounded, the dialog will appear in the background too. To always show in the foreground, use “System Events” as the app:

osascript -e 'tell app "System Events" to display dialog "Hello World"'

Read more on Mac OS X Hints.

How to fix: "You need to use a Theme.AppCompat theme (or descendant) with this activity"

If you add the android:theme="@style/Theme.AppCompat.Light" to <application> in AndroidManifest.xml file, problem is solving.

How do I deal with certificates using cURL while trying to access an HTTPS url?

Create a file ~/.curlrc with the following content

cacert=/etc/ssl/certs/ca-certificates.crt

as follows

echo "cacert=/etc/ssl/certs/ca-certificates.crt" >> ~/.curlrc

Getting a POST variable

Use this for GET values:

Request.QueryString["key"]

And this for POST values

Request.Form["key"]

Also, this will work if you don't care whether it comes from GET or POST, or the HttpContext.Items collection:

Request["key"]

Another thing to note (if you need it) is you can check the type of request by using:

Request.RequestType

Which will be the verb used to access the page (usually GET or POST). Request.IsPostBack will usually work to check this, but only if the POST request includes the hidden fields added to the page by the ASP.NET framework.

How to disable a input in angular2

And also if the input box/button has to remain disable, then simply <button disabled> or <input disabled> works.

Insert all data of a datagridview to database at once

You can do the same thing with the connection opened just once. Something like this.

for(int i=0; i< dataGridView1.Rows.Count;i++)
  {
    string StrQuery= @"INSERT INTO tableName VALUES (" + dataGridView1.Rows[i].Cells["ColumnName"].Value +", " + dataGridView1.Rows[i].Cells["ColumnName"].Value +");";

  try
  {
      SqlConnection conn = new SqlConnection();
      conn.Open();

          using (SqlCommand comm = new SqlCommand(StrQuery, conn))
          {
              comm.ExecuteNonQuery();
          }
      conn.Close();

  }

Also, depending on your specific scenario you may want to look into binding the grid to the database. That would reduce the amount of manual work greatly: http://www.switchonthecode.com/tutorials/csharp-tutorial-binding-a-datagridview-to-a-database

How to copy and edit files in Android shell?

Android supports the dd command.

dd if=/path/file of=/path/file

How to obtain the total numbers of rows from a CSV file in Python?

You can also use a classic for loop:

import pandas as pd
df = pd.read_csv('your_file.csv')

count = 0
for i in df['a_column']:
    count = count + 1

print(count)

How to redirect the output of print to a TXT file

simple in python 3.6

o = open('outfile','w')

print('hello world', file=o)

o.close()

I was looking for something like I did in Perl

my $printname = "outfile"

open($ph, '>', $printname)
    or die "Could not open file '$printname' $!";

print $ph "hello world\n";

Does swift have a trim method on String?

extension String {
    /// EZSE: Trims white space and new line characters
    public mutating func trim() {
         self = self.trimmed()
    }

    /// EZSE: Trims white space and new line characters, returns a new string
    public func trimmed() -> String {
        return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
    }
}

Taken from this repo of mine: https://github.com/goktugyil/EZSwiftExtensions/commit/609fce34a41f98733f97dfd7b4c23b5d16416206

Deleting a SQL row ignoring all foreign keys and constraints

On all tables with foreign keys pointing to this one, use:

ALTER TABLE MyOtherTable NOCHECK CONSTRAINT fk_name

Getting the client's time zone (and offset) in JavaScript

This is very good work for me:

// Translation to offset in Unix Timestamp
let timeZoneOffset = ((new Date().getTimezoneOffset())/60)*3600;

Read response headers from API response - Angular 5 + TypeScript

You should use the new HttpClient. You can find more information here.

http
  .get<any>('url', {observe: 'response'})
  .subscribe(resp => {
    console.log(resp.headers.get('X-Token'));
  });

How do I reformat HTML code using Sublime Text 2?

There are half a dozen or so ways to format HTML in Sublime. I've tested each of the most popular plugins (see the writeup I did on my blog for full details), but here's a quick overview of some of the most popular options:

Reindent command

Pros:

  • Ships with Sublime, so no plugin install needed

Cons:

  • Doesn't delete extra blank lines
  • Can't handle minified HTML, lines with multiple open tags
  • Doesn't properly format <script> blocks

Tag

Pros:

  • Supports ST2/ST3
  • Removes extra blank lines
  • No binary dependencies

Cons:

  • Chokes on PHP tags
  • Doesn't handle <script> blocks correctly

HTMLTidy

Pros:

  • Handles PHP tags
  • Some settings to tweak formatting

Cons:

  • Requires PHP (falls back to web service)
  • ST2 only
  • Abandoned?

HTMLBeautify

Pros:

  • Supports ST2/ST3
  • Simple and no binaray dependencies
  • Support for OS X, Win and Linux

Cons:

  • Chokes a bit with inline comments
  • Does expand minimized/compressed code

HTML-CSS-JS Prettify

Pros:

  • Supports ST2/ST3
  • Handles HTML, CSS, JS
  • Great integration with Sublime's menus
  • Highly customizable
  • Per-project settings
  • Format on save option

Cons:

  • Requires Node.js
  • Not great for embedded PHP

Which is best?

HTML-CSS-JS Prettify is the winner in my book. Lots of great features, not much to complain about.

What is "with (nolock)" in SQL Server?

I use with (nolock) hint particularly in SQLServer 2000 databases with high activity. I am not certain that it is needed in SQL Server 2005 however. I recently added that hint in a SQL Server 2000 at the request of the client's DBA, because he was noticing a lot of SPID record locks.

All I can say is that using the hint has NOT hurt us and appears to have made the locking problem solve itself. The DBA at that particular client basically insisted that we use the hint.

By the way, the databases I deal with are back-ends to enterprise medical claims systems, so we are talking about millions of records and 20+ tables in many joins. I typically add a WITH (nolock) hint for each table in the join (unless it is a derived table, in which case you can't use that particular hint)

How to install bcmath module?

If still anyone is not getting how to install bcmath as it has lots of other dependant modules to install like php7.2-common, etc.

Try using synaptic application, to install the same. fire command.\

sudo apt-get install synaptic

Open the synaptic application and then click on search tab.

search for bcmath

search results will show all the packages depends on php.

Install as per your convenience.

and install with all auto populated dependancies it required to install.

That's it.

Java Interfaces/Implementation naming convention

I tend to follow the pseudo-conventions established by Java Core/Sun, e.g. in the Collections classes:

  • List - interface for the "conceptual" object
  • ArrayList - concrete implementation of interface
  • LinkedList - concrete implementation of interface
  • AbstractList - abstract "partial" implementation to assist custom implementations

I used to do the same thing modeling my event classes after the AWT Event/Listener/Adapter paradigm.

iPhone Debugging: How to resolve 'failed to get the task for process'?

If you are getting such error, the only reason could be you using a Distribution profile rather than a development profile in Xcode or a missing Entitlement property. If you are not using the Entitlements.plist, then the only possible error could be the app is getting packaged with a distribution profile. You could verify this confirming the build logs. To change this, go to Build Setting of the project and verify Code Signing Entity setting. For debugging to work, this setting should be a developer profile for the configuration that you are currently using.

https://developer.apple.com/library/ios/#qa/qa1682/_index.html

For instant results, delete all mobile provisioning profiles from xcode and install the developer profile that you intend to use.

Optimal number of threads per core

The ideal is 1 thread per core, as long as none of the threads will block.

One case where this may not be true: there are other threads running on the core, in which case more threads may give your program a bigger slice of the execution time.

Detect a finger swipe through JavaScript on the iPhone and Android

Some mod of uppest answer(can't comment...) to deal with to short swipes

document.addEventListener('touchstart', handleTouchStart, false);        
document.addEventListener('touchmove', handleTouchMove, false);
var xDown = null;                                                        
var yDown = null;                                                        
function handleTouchStart(evt) {                                         
    xDown = evt.touches[0].clientX;                                      
    yDown = evt.touches[0].clientY;                                      
};                                                
function handleTouchMove(evt) {
    if ( ! xDown || ! yDown ) {
        return;
    }

    var xUp = evt.touches[0].clientX;                                    
    var yUp = evt.touches[0].clientY;

    var xDiff = xDown - xUp;
    var yDiff = yDown - yUp;
    if(Math.abs( xDiff )+Math.abs( yDiff )>150){ //to deal with to short swipes

    if ( Math.abs( xDiff ) > Math.abs( yDiff ) ) {/*most significant*/
        if ( xDiff > 0 ) {/* left swipe */ 
            alert('left!');
        } else {/* right swipe */
            alert('right!');
        }                       
    } else {
        if ( yDiff > 0 ) {/* up swipe */
            alert('Up!'); 
        } else { /* down swipe */
            alert('Down!');
        }                                                                 
    }
    /* reset values */
    xDown = null;
    yDown = null;
    }
};

How to check if a character is upper-case in Python?

words = x.split("_")
for word in words:
    if word[0] == word[0].upper() and word[1:] == word[1:].lower():
        print word, "is conformant"
    else:
        print word, "is non conformant"

Angularjs Template Default Value if Binding Null / Undefined (With Filter)

I made the following filter:

angular.module('app').filter('ifEmpty', function() {
    return function(input, defaultValue) {
        if (angular.isUndefined(input) || input === null || input === '') {
            return defaultValue;
        }

        return input;
    }
});

To be used like this:

<span>{{aPrice | currency | ifEmpty:'N/A'}}</span>
<span>{{aNum | number:3 | ifEmpty:0}}</span>

How to convert POJO to JSON and vice versa?

We can also make use of below given dependency and plugin in your pom file - I make use of maven. With the use of these you can generate POJO's as per your JSON Schema and then make use of code given below to populate request JSON object via src object specified as parameter to gson.toJson(Object src) or vice-versa. Look at the code below:

Gson gson = new GsonBuilder().create();
String payloadStr = gson.toJson(data.getMerchant().getStakeholder_list());

Gson gson2 = new Gson();
Error expectederr = gson2.fromJson(payloadStr, Error.class);

And the Maven settings:

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>1.7.1</version>
</dependency>

<plugin>
    <groupId>com.googlecode.jsonschema2pojo</groupId>
    <artifactId>jsonschema2pojo-maven-plugin</artifactId>
    <version>0.3.7</version>
    <configuration>
        <sourceDirectory>${basedir}/src/main/resources/schema</sourceDirectory>
        <targetPackage>com.example.types</targetPackage>
    </configuration>
    <executions>
        <execution>
            <phase>generate-sources</phase>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Must issue a STARTTLS command first

You are probably attempting to use Gmail's servers on port 25 to deliver mail to a third party over an unauthenticated connection. Gmail doesn't let you do this, because then anybody could use Gmail's servers to send mail to anybody else. This is called an open relay and was a common enabler of spam in the early days. Open relays are no longer acceptable on the Internet.

You will need to ask your SMTP client to connect to Gmail using an authenticated connection, probably on port 587.

How to speed up insertion performance in PostgreSQL

See populate a database in the PostgreSQL manual, depesz's excellent-as-usual article on the topic, and this SO question.

(Note that this answer is about bulk-loading data into an existing DB or to create a new one. If you're interested DB restore performance with pg_restore or psql execution of pg_dump output, much of this doesn't apply since pg_dump and pg_restore already do things like creating triggers and indexes after it finishes a schema+data restore).

There's lots to be done. The ideal solution would be to import into an UNLOGGED table without indexes, then change it to logged and add the indexes. Unfortunately in PostgreSQL 9.4 there's no support for changing tables from UNLOGGED to logged. 9.5 adds ALTER TABLE ... SET LOGGED to permit you to do this.

If you can take your database offline for the bulk import, use pg_bulkload.

Otherwise:

  • Disable any triggers on the table

  • Drop indexes before starting the import, re-create them afterwards. (It takes much less time to build an index in one pass than it does to add the same data to it progressively, and the resulting index is much more compact).

  • If doing the import within a single transaction, it's safe to drop foreign key constraints, do the import, and re-create the constraints before committing. Do not do this if the import is split across multiple transactions as you might introduce invalid data.

  • If possible, use COPY instead of INSERTs

  • If you can't use COPY consider using multi-valued INSERTs if practical. You seem to be doing this already. Don't try to list too many values in a single VALUES though; those values have to fit in memory a couple of times over, so keep it to a few hundred per statement.

  • Batch your inserts into explicit transactions, doing hundreds of thousands or millions of inserts per transaction. There's no practical limit AFAIK, but batching will let you recover from an error by marking the start of each batch in your input data. Again, you seem to be doing this already.

  • Use synchronous_commit=off and a huge commit_delay to reduce fsync() costs. This won't help much if you've batched your work into big transactions, though.

  • INSERT or COPY in parallel from several connections. How many depends on your hardware's disk subsystem; as a rule of thumb, you want one connection per physical hard drive if using direct attached storage.

  • Set a high checkpoint_segments value and enable log_checkpoints. Look at the PostgreSQL logs and make sure it's not complaining about checkpoints occurring too frequently.

  • If and only if you don't mind losing your entire PostgreSQL cluster (your database and any others on the same cluster) to catastrophic corruption if the system crashes during the import, you can stop Pg, set fsync=off, start Pg, do your import, then (vitally) stop Pg and set fsync=on again. See WAL configuration. Do not do this if there is already any data you care about in any database on your PostgreSQL install. If you set fsync=off you can also set full_page_writes=off; again, just remember to turn it back on after your import to prevent database corruption and data loss. See non-durable settings in the Pg manual.

You should also look at tuning your system:

  • Use good quality SSDs for storage as much as possible. Good SSDs with reliable, power-protected write-back caches make commit rates incredibly faster. They're less beneficial when you follow the advice above - which reduces disk flushes / number of fsync()s - but can still be a big help. Do not use cheap SSDs without proper power-failure protection unless you don't care about keeping your data.

  • If you're using RAID 5 or RAID 6 for direct attached storage, stop now. Back your data up, restructure your RAID array to RAID 10, and try again. RAID 5/6 are hopeless for bulk write performance - though a good RAID controller with a big cache can help.

  • If you have the option of using a hardware RAID controller with a big battery-backed write-back cache this can really improve write performance for workloads with lots of commits. It doesn't help as much if you're using async commit with a commit_delay or if you're doing fewer big transactions during bulk loading.

  • If possible, store WAL (pg_xlog) on a separate disk / disk array. There's little point in using a separate filesystem on the same disk. People often choose to use a RAID1 pair for WAL. Again, this has more effect on systems with high commit rates, and it has little effect if you're using an unlogged table as the data load target.

You may also be interested in Optimise PostgreSQL for fast testing.

How to detect duplicate values in PHP array?

You can use array_count_values function

$array = array('apple', 'orange', 'pear', 'banana', 'apple',
'pear', 'kiwi', 'kiwi', 'kiwi');

print_r(array_count_values($array));

will output

Array
(
   [apple] => 2
   [orange] => 1
   [pear] => 2
   etc...
)

PHP: convert spaces in string into %20?

I believe that, if you need to use the %20 variant, you could perhaps use rawurlencode().

How do I get the current time zone of MySQL?

It may be

select timediff(current_time(),utc_time())

You won't get the timezone value directly this way.

@@global.time_zone cannot be used as it is a variable, and it returns the value 'SYSTEM'.

If you need to use your query in a session with a changed timezone by using session SET TIME_ZONE =, then you will get that with @@session.time_zone. If you query @@global.time_zone, then you get 'SYSTEM'.

If you try datediff, date_sub, or timediff with now() and utc_time(), then you'll probably run into conversion issues.

But the things suggested above will probably work at least with some server versions. My version is 5.5.43-37 and is a hosted solution.

accessing a file using [NSBundle mainBundle] pathForResource: ofType:inDirectory:

Try this, it's working for me.

NSString *str = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"paylines.txt"];  

For simulator

NSURL *rtfUrl = [[NSBundle mainBundle] URLForResource:@"paylines" withExtension:@".txt"];

Shortcut to Apply a Formula to an Entire Column in Excel

Select a range of cells (the entire column in this case), type in your formula, and hold down Ctrl while you press Enter. This places the formula in all selected cells.

How can I count the numbers of rows that a MySQL query returned?

SELECT SQL_CALC_FOUND_ROWS *
FROM   table1
WHERE  ...;

SELECT FOUND_ROWS();

FOUND_ROWS() must be called immediately after the query.

How to access custom attributes from event object in React?

To help you get the desired outcome in perhaps a different way than you asked:

render: function() {
    ...
    <a data-tag={i} style={showStyle} onClick={this.removeTag.bind(null, i)}></a>
    ...
},
removeTag: function(i) {
    // do whatever
},

Notice the bind(). Because this is all javascript, you can do handy things like that. We no longer need to attach data to DOM nodes in order to keep track of them.

IMO this is much cleaner than relying on DOM events.

Update April 2017: These days I would write onClick={() => this.removeTag(i)} instead of .bind

SSIS Excel Connection Manager failed to Connect to the Source

Here's the solution that works fine for me.

I just Saved the Excel file as an Excel 97-2003 Version. enter image description here

How to concatenate multiple lines of output to one line?

The fastest and easiest ways I know to solve this problem:

When we want to replace the new line character \n with the space:

xargs < file

xargs has own limits on the number of characters per line and the number of all characters combined, but we can increase them. Details can be found by running this command: xargs --show-limits and of course in the manual: man xargs

When we want to replace one character with another exactly one character:

tr '\n' ' ' < file

When we want to replace one character with many characters:

tr '\n' '~' < file | sed s/~/many_characters/g

First, we replace the newline characters \n for tildes ~ (or choose another unique character not present in the text), and then we replace the tilde characters with any other characters (many_characters) and we do it for each tilde (flag g).

In Java, what does NaN mean?

NaN means “Not a Number” and is basically a representation of a special floating point value in the IEE 754 floating point standard. NaN generally means that the value is something that cannot be expressed with a valid floating point number.

A conversion will result in this value, when the value being converted is something else, for example when converting a string that does not represent a number.

java.net.URLEncoder.encode(String) is deprecated, what should I use instead?

You should use:

URLEncoder.encode("NAME", "UTF-8");

How to show/hide JPanels in a JFrame?

You can hide a JPanel by calling setVisible(false). For example:

public static void main(String args[]){
    JFrame f = new JFrame();
    f.setLayout(new BorderLayout());
    final JPanel p = new JPanel();
    p.add(new JLabel("A Panel"));
    f.add(p, BorderLayout.CENTER);

    //create a button which will hide the panel when clicked.
    JButton b = new JButton("HIDE");
    b.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
                p.setVisible(false);
        }
    });

    f.add(b,BorderLayout.SOUTH);
    f.pack();
    f.setVisible(true);
}

How to convert a byte array to Stream

Easy, simply wrap a MemoryStream around it:

Stream stream = new MemoryStream(buffer);

Press any key to continue

I've created a little Powershell function to emulate MSDOS pause. This handles whether running Powershell ISE or non ISE. (ReadKey does not work in powershell ISE). When running Powershell ISE, this function opens a Windows MessageBox. This can sometimes be confusing, because the MessageBox does not always come to the forefront. Anyway, here it goes:

Usage: pause "Press any key to continue"

Function definition:

Function pause ($message)
{
    # Check if running Powershell ISE
    if ($psISE)
    {
        Add-Type -AssemblyName System.Windows.Forms
        [System.Windows.Forms.MessageBox]::Show("$message")
    }
    else
    {
        Write-Host "$message" -ForegroundColor Yellow
        $x = $host.ui.RawUI.ReadKey("NoEcho,IncludeKeyDown")
    }
}

Invoke or BeginInvoke cannot be called on a control until the window handle has been created

If you're going to use a Control from another thread before showing or doing other things with the Control, consider forcing the creation of its handle within the constructor. This is done using the CreateHandle function.

In a multi-threaded project, where the "controller" logic isn't in a WinForm, this function is instrumental in Control constructors for avoiding this error.

m2eclipse error

I had same problem with Eclipse 3.7.2 (Indigo) and maven 3.0.4.

In my case, the problem was caused by missing maven-resources-plugin-2.4.3.jar in {user.home}\.m2\repository\org\apache\maven\plugins\maven-resources-plugin\2.4.3 folder. (no idea why maven didn't update it)

Solution:

1.) add dependency to pom.xml

<dependency>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-resources-plugin</artifactId>
    <version>2.4.3</version>
</dependency>

2.) run mvn install from Eclipse or from command line

3.) refresh the project in eclipse (F5)

4.) run Maven > Update Project Configuration... on project (right click)

JAR file is downloaded to local repository and there are no errors in WS.

How to create an empty R vector to add new items

vec <- vector()

See also vector help

?vector

Clear an input field with Reactjs?

Also after React v 16.8+ you have an ability to use hooks

import React, {useState} from 'react';

const ControlledInputs = () => {
  const [firstName, setFirstName] = useState(false);

  const handleSubmit = (e) => {
    e.preventDefault();
    if (firstName) {
      console.log('firstName :>> ', firstName);
    }
  };

  return (
    <>
      <form onSubmit={handleSubmit}>
          <label htmlFor="firstName">Name: </label>
          <input
            type="text"
            id="firstName"
            name="firstName"
            value={firstName}
            onChange={(e) => setFirstName(e.target.value)}
          />
        <button type="submit">add person</button>
      </form>
    </>
  );
};

Could not find or load main class org.gradle.wrapper.GradleWrapperMain

you can also copy the gradlew.bat into you root folder and copy the gradlew-wrapper into gradlew folder.

that's work for me.

CSS how to make an element fade in and then fade out?

Use css @keyframes

.elementToFadeInAndOut {
    opacity: 1;
    animation: fade 2s linear;
}


@keyframes fade {
  0%,100% { opacity: 0 }
  50% { opacity: 1 }
}

here is a DEMO

_x000D_
_x000D_
.elementToFadeInAndOut {_x000D_
    width:200px;_x000D_
    height: 200px;_x000D_
    background: red;_x000D_
    -webkit-animation: fadeinout 4s linear forwards;_x000D_
    animation: fadeinout 4s linear forwards;_x000D_
}_x000D_
_x000D_
@-webkit-keyframes fadeinout {_x000D_
  0%,100% { opacity: 0; }_x000D_
  50% { opacity: 1; }_x000D_
}_x000D_
_x000D_
@keyframes fadeinout {_x000D_
  0%,100% { opacity: 0; }_x000D_
  50% { opacity: 1; }_x000D_
}
_x000D_
<div class=elementToFadeInAndOut></div>
_x000D_
_x000D_
_x000D_

Reading: Using CSS animations

You can clean the code by doing this:

_x000D_
_x000D_
.elementToFadeInAndOut {_x000D_
    width:200px;_x000D_
    height: 200px;_x000D_
    background: red;_x000D_
    -webkit-animation: fadeinout 4s linear forwards;_x000D_
    animation: fadeinout 4s linear forwards;_x000D_
    opacity: 0;_x000D_
}_x000D_
_x000D_
@-webkit-keyframes fadeinout {_x000D_
  50% { opacity: 1; }_x000D_
}_x000D_
_x000D_
@keyframes fadeinout {_x000D_
  50% { opacity: 1; }_x000D_
}
_x000D_
<div class=elementToFadeInAndOut></div>
_x000D_
_x000D_
_x000D_

Select row on click react-table

I found the solution after a few tries, I hope this can help you. Add the following to your <ReactTable> component:

getTrProps={(state, rowInfo) => {
  if (rowInfo && rowInfo.row) {
    return {
      onClick: (e) => {
        this.setState({
          selected: rowInfo.index
        })
      },
      style: {
        background: rowInfo.index === this.state.selected ? '#00afec' : 'white',
        color: rowInfo.index === this.state.selected ? 'white' : 'black'
      }
    }
  }else{
    return {}
  }
}

In your state don't forget to add a null selected value, like:

state = { selected: null }

Clearing my form inputs after submission

var btnClear = document.querySelector('button');
var inputs = document.querySelectorAll('input');
 
btnClear.addEventListener('click', () => {
    inputs.forEach(input =>  input.value = '');
});

Get pixel's RGB using PIL

Not PIL, but imageio.imread might still be interesting:

import imageio
im = scipy.misc.imread('um_000000.png', flatten=False, mode='RGB')
im = imageio.imread('Figure_1.png', pilmode='RGB')
print(im.shape)

gives

(480, 640, 3)

so it is (height, width, channels). So the pixel at position (x, y) is

color = tuple(im[y][x])
r, g, b = color

Outdated

scipy.misc.imread is deprecated in SciPy 1.0.0 (thanks for the reminder, fbahr!)

Responsive iframe using Bootstrap

Option 1

With Bootstrap 3.2 you can wrap each iframe in the responsive-embed wrapper of your choice:

http://getbootstrap.com/components/#responsive-embed

<!-- 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
  <iframe class="embed-responsive-item" src="…"></iframe>
</div>

<!-- 4:3 aspect ratio -->
<div class="embed-responsive embed-responsive-4by3">
  <iframe class="embed-responsive-item" src="…"></iframe>
</div>

Option 2

If you don't want to wrap your iframes, you can use FluidVids https://github.com/toddmotto/fluidvids. See demo here: http://toddmotto.com/labs/fluidvids/

   <!-- fluidvids.js -->
    <script src="js/fluidvids.js"></script>
    <script>
    fluidvids.init({
      selector: ['iframe'],
      players: ['www.youtube.com', 'player.vimeo.com']
    });
    </script>

Getting Keyboard Input

You can also make it with BufferedReader if you want to validate user input, like this:

import java.io.BufferedReader;
import java.io.InputStreamReader; 
class Areas {
    public static void main(String args[]){
        float PI = 3.1416f;
        int r=0;
        String rad; //We're going to read all user's text into a String and we try to convert it later
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); //Here you declare your BufferedReader object and instance it.
        System.out.println("Radius?");
        try{
            rad = br.readLine(); //We read from user's input
            r = Integer.parseInt(rad); //We validate if "rad" is an integer (if so we skip catch call and continue on the next line, otherwise, we go to it (catch call))
            System.out.println("Circle area is: " + PI*r*r + " Perimeter: " +PI*2*r); //If all was right, we print this
        }
        catch(Exception e){
            System.out.println("Write an integer number"); //This is what user will see if he/she write other thing that is not an integer
            Areas a = new Areas(); //We call this class again, so user can try it again
           //You can also print exception in case you want to see it as follows:
           // e.printStackTrace();
        }
    }
}

Because Scanner class won't allow you to do it, or not that easy...

And to validate you use "try-catch" calls.

Error when creating a new text file with python?

This works just fine, but instead of

name = input('Enter name of text file: ')+'.txt' 

you should use

name = raw_input('Enter name of text file: ')+'.txt'

along with

open(name,'a') or open(name,'w')

change text of button and disable button in iOS

In Swift 3, you can simply change the title of a button by:

button.setTitle("Title", for: .normal)

and you disable the button by:

button.isEnabled = false

.normal is the same as UIControlState.normal because the type is inferred.

Launch an event when checking a checkbox in Angular2

StackBlitz

Template: You can either use the native change event or NgModel directive's ngModelChange.

<input type="checkbox" (change)="onNativeChange($event)"/>

or

<input type="checkbox" ngModel (ngModelChange)="onNgModelChange($event)"/>

TS:

onNativeChange(e) { // here e is a native event
  if(e.target.checked){
    // do something here
  }
}

onNgModelChange(e) { // here e is a boolean, true if checked, otherwise false
  if(e){
    // do something here
  }
}

Using jQuery to build table rows from AJAX response(json)

You could do it something like this:

<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">

<!-- jQuery library -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>

<!-- Latest compiled JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>


    <script>
    $(function(){

    $.ajax({
    url: '<Insert your REST API which you want GET/POST/PUT/DELETE>',
    data: '<any parameters you want to send as the Request body or query string>',
    dataType: json,
    async: true,
    method: "GET"
    success: function(data){

    //If the REST API returned a successful response it'll be stored in data, 
    //just parse that field using jQuery and you're all set

    var tblSomething = '<thead> <tr> <td> Heading Col 1 </td> <td> Heading Col 2 </td> <td> Col 3 </td> </tr> </thead> <tbody>';

    $.each(data, function(idx, obj){

    //Outer .each loop is for traversing the JSON rows
    tblSomething += '<tr>';

    //Inner .each loop is for traversing JSON columns
    $.each(obj, function(key, value){
    tblSomething += '<td>' + value + '</td>';
    });
    tblSomething += '</tr>';
    });

    tblSomething += '</tbody>';

    $('#tblSomething').html(tblSomething);
    },
    error: function(jqXHR, textStatus, errorThrown){
    alert('Hey, something went wrong because: ' + errorThrown);
    }
    });


    });
    </script>


    <table id = "tblSomething" class = "table table-hover"></table>

How to insert a line break in a SQL Server VARCHAR/NVARCHAR string

I found the answer here: http://blog.sqlauthority.com/2007/08/22/sql-server-t-sql-script-to-insert-carriage-return-and-new-line-feed-in-code/

You just concatenate the string and insert a CHAR(13) where you want your line break.

Example:

DECLARE @text NVARCHAR(100)
SET @text = 'This is line 1.' + CHAR(13) + 'This is line 2.'
SELECT @text

This prints out the following:

This is line 1.
This is line 2.

Make a link open a new window (not tab)

You can try this:-

   <a href="some.htm" target="_blank">Link Text</a>

and you can try this one also:-

  <a href="some.htm" onclick="if(!event.ctrlKey&&!window.opera){alert('Hold the Ctrl Key');return false;}else{return true;}" target="_blank">Link Text</a>

How to concat string + i?

You can concatenate strings using strcat. If you plan on concatenating numbers as strings, you must first use num2str to convert the numbers to strings.

Also, strings can't be stored in a vector or matrix, so f must be defined as a cell array, and must be indexed using { and } (instead of normal round brackets).

f = cell(N, 1);
for i=1:N
   f{i} = strcat('f', num2str(i));
end

How to query values from xml nodes?

Try this:

SELECT RawXML.value('(/GrobXmlFile//Grob//ReportHeader//OrganizationReportReferenceIdentifier/node())[1]','varchar(50)') AS ReportIdentifierNumber,
       RawXML.value('(/GrobXmlFile//Grob//ReportHeader//OrganizationNumber/node())[1]','int') AS OrginazationNumber
FROM Batches

Bash script to run php script

I found php-cgi on my server. And its on environment path so I was able to run from anywhere. I executed succesfuly file.php in my bash script.

#!/bin/bash
php-cgi ../path/file.php

And the script returned this after php script was executed:

X-Powered-By: PHP/7.1.1 Content-type: text/html; charset=UTF-8

done!

By the way, check first if it works by checking the version issuing the command php-cgi -v

Assign an initial value to radio button as checked

Note that if you have two radio button with same "name" attribute and they have "required" attribute, then adding "checked" attribute to them won't make them checked.

Example: This makes both radio button remain unchecked.

<input type="radio" name="gender" value="male" required <?php echo "checked"; ?>/>
<input type="radio" name="gender" value="female" required />

This will makes the "male" radio button checked.

<input type="radio" name="gender" value="male" <?php echo "checked"; ?>/>
<input type="radio" name="gender" value="female" />

How can I rename column in laravel using migration?

Follow these steps, respectively for rename column migration file.

1- Is there Doctrine/dbal library in your project. If you don't have run the command first

composer require doctrine/dbal

2- create update migration file for update old migration file. Warning (need to have the same name)

php artisan make:migration update_oldFileName_table

for example my old migration file name: create_users_table update file name should : update_users_table

3- update_oldNameFile_table.php

Schema::table('users', function (Blueprint $table) {
$table->renameColumn('from', 'to');
});

'from' my old column name and 'to' my new column name

4- Finally run the migrate command

php artisan migrate

Source link: laravel document

SQL Server Operating system error 5: "5(Access is denied.)"

In linux, I went to /var/opt/mssql/data/ folder and opened a terminal with sudo then, changed my *.mdf and *.ldf file permissions as below in which you replace yourDB with your Database file name and myUser to currently logged username:

chmod 755 yourDB.mdf
chown myUser yourDB.mdf

chmod 755 yourDB.ldf
chown myUser yourDB.ldf

After that, it was reconnected without any issue.

Android textview usage as label and value

You should implement a Custom List View, such that you define a Layout once and draw it for every row in the list view.

How to add a custom CA Root certificate to the CA Store used by pip in Windows?

Alternative solution on Windows is to install python-certifi-win32 that will allow Python to use Windows Certificate Store.

pip install python-certifi-win32

Permission denied on CopyFile in VBS

It's worth checking task manager for any stray wscript.exe tasks that are stuck. It could be one of those that's blocking access to the file.

Using any() and all() to check if a list contains one set of values or another

Generally speaking:

all and any are functions that take some iterable and return True, if

  • in the case of all(), no values in the iterable are falsy;
  • in the case of any(), at least one value is truthy.

A value x is falsy iff bool(x) == False. A value x is truthy iff bool(x) == True.

Any non-booleans in the iterable will be fine — bool(x) will coerce any x according to these rules: 0, 0.0, None, [], (), [], set(), and other empty collections will yield False, anything else True. The docstring for bool uses the terms 'true'/'false' for 'truthy'/'falsy', and True/False for the concrete boolean values.


In your specific code samples:

You misunderstood a little bit how these functions work. Hence, the following does something completely not what you thought:

if any(foobars) == big_foobar:

...because any(foobars) would first be evaluated to either True or False, and then that boolean value would be compared to big_foobar, which generally always gives you False (unless big_foobar coincidentally happened to be the same boolean value).

Note: the iterable can be a list, but it can also be a generator/generator expression (˜ lazily evaluated/generated list) or any other iterator.

What you want instead is:

if any(x == big_foobar for x in foobars):

which basically first constructs an iterable that yields a sequence of booleans—for each item in foobars, it compares the item to big_foobar and emits the resulting boolean into the resulting sequence:

tmp = (x == big_foobar for x in foobars)

then any walks over all items in tmp and returns True as soon as it finds the first truthy element. It's as if you did the following:

In [1]: foobars = ['big', 'small', 'medium', 'nice', 'ugly']                                        

In [2]: big_foobar = 'big'                                                                          

In [3]: any(['big' == big_foobar, 'small' == big_foobar, 'medium' == big_foobar, 'nice' == big_foobar, 'ugly' == big_foobar])        
Out[3]: True

Note: As DSM pointed out, any(x == y for x in xs) is equivalent to y in xs but the latter is more readable, quicker to write and runs faster.

Some examples:

In [1]: any(x > 5 for x in range(4))
Out[1]: False

In [2]: all(isinstance(x, int) for x in range(10))
Out[2]: True

In [3]: any(x == 'Erik' for x in ['Erik', 'John', 'Jane', 'Jim'])
Out[3]: True

In [4]: all([True, True, True, False, True])
Out[4]: False

See also: http://docs.python.org/2/library/functions.html#all

jquery how to use multiple ajax calls one after the end of the other

We can simply use

async: false 

This will do your need.

Reference - What does this regex mean?

The Stack Overflow Regular Expressions FAQ

See also a lot of general hints and useful links at the tag details page.


Online tutorials

Quantifiers

Character Classes

Escape Sequences

Anchors

(Also see "Flavor-Specific Information ? Java ? The functions in Matcher")

Groups

Lookarounds

Modifiers

Other:

Common Tasks

Advanced Regex-Fu

Flavor-Specific Information

(Except for those marked with *, this section contains non-Stack Overflow links.)

General information

(Links marked with * are non-Stack Overflow links.)

Examples of regex that can cause regex engine to fail

Tools: Testers and Explainers

(This section contains non-Stack Overflow links.)

What does the 'L' in front a string mean in C++?

L is a prefix used for wide strings. Each character uses several bytes (depending on the size of wchar_t). The encoding used is independent from this prefix. I mean it must not be necessarily UTF-16 unlike stated in other answers here.

.htaccess mod_rewrite - how to exclude directory from rewrite rule

RewriteEngine On

RewriteRule ^(wordpress)($|/) - [L]

'tsc command not found' in compiling typescript

I had this same problem on Ubuntu 19.10 LTS.

To solve this I ran the following command:

$ sudo apt install node-typescript

After that, I was able to use tsc.

How to create permanent PowerShell Aliases

I found that I can run this command:

notepad $((Split-Path $profile -Parent) + "\profile.ps1")

and it opens my default powershell profile (at least when using Terminal for Windows). I found that here.

Then add an alias. For example, here is my alias of jn for jupyter notebook (I hate typing out the cumbersome jupyter notebook every time):

Set-Alias -Name jn -Value C:\Users\words\Anaconda3\Scripts\jupyter-notebook.exe

How can I force Python's file.write() to use the same newline format in Windows as in Linux ("\r\n" vs. "\n")?

You can still use the textmode and force the linefeed-newline with the keyword argument newline

f = open("./foo",'w',newline='\n')

Tested with Python 3.4.2.

Edit: This does not work in Python 2.7.

python: how to identify if a variable is an array or a scalar

To answer the question in the title, a direct way to tell if a variable is a scalar is to try to convert it to a float. If you get TypeError, it's not.

N = [1, 2, 3]
try:
    float(N)
except TypeError:
    print('it is not a scalar')
else:
    print('it is a scalar')

Cancel a vanilla ECMAScript 6 Promise chain

If your code is placed in a class you could use a decorator for that. You have such decorator in the utils-decorators (npm install --save utils-decorators). It will cancel the previous invocation of the decorated method if before the resolving of the previous call there was made another call for that specific method.

import {cancelPrevious} from 'utils-decorators';

class SomeService {

   @cancelPrevious()
   doSomeAsync(): Promise<any> {
    ....
   }
}

or you could use a wrapper function:

import {cancelPreviousify} from 'utils-decorators';

const cancelable = cancelPreviousify(originalMethod)

https://github.com/vlio20/utils-decorators#cancelprevious-method

How to print a debug log?

You can use error_log to send to your servers error log file (or an optional other file if you'd like)

Send value of submit button when form gets posted

You could use something like this to give your button a value:

<?php
if (isset($_POST['submit'])) {
  $aSubmitVal = array_keys($_POST['submit'])[0];
  echo 'The button value is: ' . $aSubmitVal;
}
?>
<form action="/" method="post">
  <input id="someId" type="submit" name="submit[SomeValue]" value="Button name">
</form>

This will give you the string "SomeValue" as a result

https://i.imgur.com/28gr7Uy.gif

Iterator over HashMap in Java

Several problems here:

  • You probably don't use the correct iterator class. As others said, use import java.util.Iterator
  • If you want to use Map.Entry entry = (Map.Entry) iter.next(); then you need to use hm.entrySet().iterator(), not hm.keySet().iterator(). Either you iterate on the keys, or on the entries.

How to calculate the width of a text string of a specific font and font-size?

Update Sept 2019

This answer is a much cleaner way to do it using new syntax.

Original Answer

Based on Glenn Howes' excellent answer, I created an extension to calculate the width of a string. If you're doing something like setting the width of a UISegmentedControl, this can set the width based on the segment's title string.

extension String {

    func widthOfString(usingFont font: UIFont) -> CGFloat {
        let fontAttributes = [NSAttributedString.Key.font: font]
        let size = self.size(withAttributes: fontAttributes)
        return size.width
    }

    func heightOfString(usingFont font: UIFont) -> CGFloat {
        let fontAttributes = [NSAttributedString.Key.font: font]
        let size = self.size(withAttributes: fontAttributes)
        return size.height
    }

    func sizeOfString(usingFont font: UIFont) -> CGSize {
        let fontAttributes = [NSAttributedString.Key.font: font]
        return self.size(withAttributes: fontAttributes)
    }
}

usage:

    // Set width of segmentedControl
    let starString = "??"
    let starWidth = starString.widthOfString(usingFont: UIFont.systemFont(ofSize: 14)) + 16
    segmentedController.setWidth(starWidth, forSegmentAt: 3)

Can (domain name) subdomains have an underscore "_" in it?

A note on terminology, in furtherance to Bortzmeyer's answer

One should be clear about definitions. As used here:

  • domain name is the identifier of a resource in a DNS database
  • label is the part of a domain name in between dots
  • hostname is a special type of domain name which identifies Internet hosts

The hostname is subject to the restrictions of RFC 952 and the slight relaxation of RFC 1123

RFC 2181 makes clear that there is a difference between a domain name and a hostname:

...[the fact that] any binary label can have an MX record does not imply that any binary name can be used as the host part of an e-mail address...

So underscores in hostnames are a no-no, underscores in domain names are a-ok.

In practice, one may well see hostnames with underscores. As the Robustness Principle says: "Be conservative in what you send, liberal in what you accept".

A note on encoding

In the 21st century, it turns out that hostnames as well as domain names may be internationalized! This means resorting to encodings in case of labels that contain characters that are outside the allowed set.

In particular, it allows one to encode the _ in hostnames (Update 2017-07: This is doubtful, see comments. The _ still cannot be used in hostnames. Indeed, it cannot even be used in internationalized labels.)

The first RFC for internationalization was RFC 3490 of March 2003, "Internationalizing Domain Names in Applications (IDNA)". Today, we have:

  • RFC 5890 "IDNA: Definitions and Document Framework"
  • RFC 5891 "IDNA: Protocol"
  • RFC 5892 "The Unicode Code Points and IDNA"
  • RFC 5893 "Right-to-Left Scripts for IDNA"
  • RFC 5894 "IDNA: Background, Explanation, and Rationale"
  • RFC 5895 "Mapping Characters for IDNA 2008"

You may also want to check the Wikipedia Entry

RFC 5890 introduces the term LDH (Letter-Digit-Hypen) label for labels used in hostnames and says:

This is the classical label form used, albeit with some additional restrictions, in hostnames (RFC 952). Its syntax is identical to that described as the "preferred name syntax" in Section 3.5 of RFC 1034 as modified by RFC 1123. Briefly, it is a string consisting of ASCII letters, digits, and the hyphen with the further restriction that the hyphen cannot appear at the beginning or end of the string. Like all DNS labels, its total length must not exceed 63 octets.

Going back to simpler times, this Internet draft is an early proposal for hostname internationalization. Hostnames with international characters may be encoded using, for example, 'RACE' encoding.

The author of the 'RACE encoding' proposal notes:

According to RFC 1035, host parts must be case-insensitive, start and end with a letter or digit, and contain only letters, digits, and the hyphen character ("-"). This, of course, excludes any internationalized characters, as well as many other characters in the ASCII character repertoire. Further, domain name parts must be 63 octets or shorter in length.... All post-converted name parts that contain internationalized characters begin with the string "bq--". (...) The string "bq--" was chosen because it is extremely unlikely to exist in host parts before this specification was produced.

Face recognition Library

You can try open MVG library, It can be used for multiple interfaces too.

ASP.NET MVC Razor render without encoding

As well as the already mentioned @Html.Raw(string) approach, if you output an MvcHtmlString it will not be encoded. This can be useful when adding your own extensions to the HtmlHelper, or when returning a value from your view model that you know may contain html.

For example, if your view model was:

public class SampleViewModel
{
  public string SampleString { get; set; }
  public MvcHtmlString SampleHtmlString { get; set; }
}

For Core 1.0+ (and MVC 5+) use HtmlString

public class SampleViewModel
{
  public string SampleString { get; set; }
  public HtmlString SampleHtmlString { get; set; }
}

then

<!-- this will be encoded -->
<div>@Model.SampleString</div>
<!-- this will not be encoded -->
<div>@Html.Raw(Model.SampleString)</div>
<!-- this will not be encoded either -->
<div>@Model.SampleHtmlString</div>

Get Locale Short Date Format using javascript

There is no easy way. If you want a reliable, cross-browser solution, you'd have to build a lookup table of date, and time format strings, by culture. To format a date, parse the corresponding format string, extract the relevant parts from the date, i.e. day, month, year, and append them together.

This is essentially what Microsoft does with their AJAX library, as shown in @no's answer.

Getting the docstring from a function

On ipython or jupyter notebook, you can use all the above mentioned ways, but i go with

my_func?

or

?my_func

for quick summary of both method signature and docstring.

I avoid using

my_func??

(as commented by @rohan) for docstring and use it only to check the source code

Private Variables and Methods in Python

Double underscore. That mangles the name. The variable can still be accessed, but it's generally a bad idea to do so.

Use single underscores for semi-private (tells python developers "only change this if you absolutely must") and doubles for fully private.

PowerShell: how to grep command output?

For a more flexible and lazy solution, you could match all properties of the objects. Most of the time, this should get you the behavior you want, and you can always be more specific when it doesn't. Here's a grep function that works based on this principle:

Function Select-ObjectPropertyValues {
    param(
    [Parameter(Mandatory=$true,Position=0)]
    [String]
    $Pattern,
    [Parameter(ValueFromPipeline)]
    $input)

    $input | Where-Object {($_.PSObject.Properties | Where-Object {$_.Value -match $Pattern} | Measure-Object).count -gt 0} | Write-Output
}

CGRectMake, CGPointMake, CGSizeMake, CGRectZero, CGPointZero is unavailable in Swift

You can use this with replacement of CGRectZero

CGRect.zero

How Many Seconds Between Two Dates?

var a = new Date("2010 jan 10"),
    b = new Date("2010 jan 9");

alert(
    a + "\n" + 
    b + "\n" +
    "Difference: " + ((+a - +b) / 1000)
);

When do I need to do "git pull", before or after "git add, git commit"?

I'd suggest pulling from the remote branch as often as possible in order to minimise large merges and possible conflicts.

Having said that, I would go with the first option:

git add foo.js
git commit foo.js -m "commit"
git pull
git push

Commit your changes before pulling so that your commits are merged with the remote changes during the pull. This may result in conflicts which you can begin to deal with knowing that your code is already committed should anything go wrong and you have to abort the merge for whatever reason.

I'm sure someone will disagree with me though, I don't think there's any correct way to do this merge flow, only what works best for people.

QString to char* conversion

Qt provides the simplest API

const char *qPrintable(const QString &str)
const char *qUtf8Printable(const QString &str)

If you want non-const data pointer use

str.toLocal8Bit().data()
str.toUtf8().data()

JavaScript Extending Class

I can propose one variant, just have read in book, it seems the simplest:

function Parent() { 
  this.name = 'default name';
};

function Child() {
  this.address = '11 street';
};

Child.prototype = new Parent();      // child class inherits from Parent
Child.prototype.constructor = Child; // constructor alignment

var a = new Child(); 

console.log(a.name);                // "default name" trying to reach property of inherited class

How can I check the size of a collection within a Django template?

You can try with:

{% if theList.object_list.count > 0 %}
    blah, blah...
{% else %}
    blah, blah....
{% endif %} 

how to convert object into string in php

you have the print_r function DOC

Applying CSS styles to all elements inside a DIV

Write all class/id CSS as below. #applyCSS ID will be parent of all CSS code.

For example you add class .ui-bar-a in CSS for applying to your div:

#applyCSS .ui-bar-a  { font-size:11px; } /* This will be your CSS part */

Below is your HTML part:

<div id="applyCSS">
   <div class="ui-bar-a">testing</div>
</div>

psql: server closed the connection unexepectedly

It turns out it is because there was a mismatch between the postgre SQL version between my local and the server, installing the same version of PostgreSQL in my computer fixed the issue. Thanks!

How to convert IPython notebooks to PDF and HTML?

The simplest way I think is 'Ctrl+P' > save as 'pdf'. That's it.

How to set image for bar button with swift?

If your UIBarButtonItem is already allocated like in a storyboard. (printBtn)

    let btn = UIButton(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
    btn.setImage(UIImage(named: Constants.ImageName.print)?.withRenderingMode(.alwaysTemplate), for: .normal)
    btn.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handlePrintPress(tapGesture:))))
    printBtn.customView = btn

How to change a dataframe column from String type to Double type in PySpark?

the solution was simple -

toDoublefunc = UserDefinedFunction(lambda x: float(x),DoubleType())
changedTypedf = joindf.withColumn("label",toDoublefunc(joindf['show']))

How to scale a UIImageView proportionally?

Here is how you can scale it easily.

This works in 2.x with the Simulator and the iPhone.

UIImage *thumbnail = [originalImage _imageScaledToSize:CGSizeMake(40.0, 40.0) interpolationQuality:1];

What's the simplest way of detecting keyboard input in a script from the terminal?

Inspired from code found above (credits), the simple blocking (aka not CPU consuming) macOS version I was looking for:

import termios
import sys
import fcntl
import os

def getKeyCode(blocking = True):
    fd = sys.stdin.fileno()
    oldterm = termios.tcgetattr(fd)
    newattr = termios.tcgetattr(fd)
    newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
    termios.tcsetattr(fd, termios.TCSANOW, newattr)
    if not blocking:
        oldflags = fcntl.fcntl(fd, fcntl.F_GETFL)
        fcntl.fcntl(fd, fcntl.F_SETFL, oldflags | os.O_NONBLOCK)
    try:
        return ord(sys.stdin.read(1))
    except IOError:
        return 0
    finally:
        termios.tcsetattr(fd, termios.TCSAFLUSH, oldterm)
        if not blocking:
            fcntl.fcntl(fd, fcntl.F_SETFL, oldflags)

def getKeyStroke():
    code  = getKeyCode()
    if code == 27:
        code2 = getKeyCode(blocking = False)
        if code2 == 0:
            return "esc"
        elif code2 == 91:
            code3 = getKeyCode(blocking = False)
            if code3 == 65:
                return "up"
            elif code3 == 66:
                return "down"
            elif code3 == 68:
                return "left"
            elif code3 == 67:
                return "right"
            else:
                return "esc?"
    elif code == 127:
        return "backspace"
    elif code == 9:
        return "tab"
    elif code == 10:
        return "return"
    elif code == 195 or code == 194:        
        code2 = getKeyCode(blocking = False)
        return chr(code)+chr(code2) # utf-8 char
    else:
        return chr(code)


while True:
    print getKeyStroke()

2017-11-09, EDITED: Not tested with Python 3

jquery : focus to div is not working

Focus doesn't work on divs by default. But, according to this, you can make it work:

The focus event is sent to an element when it gains focus. This event is implicitly applicable to a limited set of elements, such as form elements (<input>, <select>, etc.) and links (<a href>). In recent browser versions, the event can be extended to include all element types by explicitly setting the element's tabindex property. An element can gain focus via keyboard commands, such as the Tab key, or by mouse clicks on the element.

http://api.jquery.com/focus/

Get MAC address using shell script

Simply run:

ifconfig | grep ether | cut -d " " -f10

OR

ip a | grep ether | cut -d " " -f6

These two example commands will grep all lines with "ether" string and cut the mac address (that we need) following the number spaces (specified in the -f option) of the grepped portion.

Tested on different Linux flavors

How do I set up NSZombieEnabled in Xcode 4?

I find this alternative more convenient:

  1. Click the "Run Button Dropdown"
  2. From the list choose Profile
  3. The program "Instruments" should open where you can also choose Zombies
  4. Now you can interact with your app and try to cause the error
  5. As soon as the error happens you should get a hint on when your object was released and therefore deallocated.

Zombies

As soon as a zombie is detected you then get a neat "Zombie Stack" that shows you when the object in question was allocated and where it was retained or released:

Event Type    RefCt     Responsible Caller
Malloc            1     -[MyViewController loadData:]
Retain            2     -[MyDataManager initWithBaseURL:]
Release           1     -[MyDataManager initWithBaseURL:]
Release           0     -[MyViewController loadData:]
Zombie           -1     -[MyService prepareURLReuqest]

Advantages compared to using the diagnostic tab of the Xcode Schemes:

  1. If you forget to uncheck the option in the diagnostic tab there no objects will be released from memory.

  2. You get a more detailed stack that shows you in what methods your corrupt object was allocated / released or retained.

Java : Accessing a class within a package, which is the better way?

No, it doesn't save you memory.

Also note that you don't have to import Math at all. Everything in java.lang is imported automatically.

A better example would be something like an ArrayList

import java.util.ArrayList;
....
ArrayList<String> i = new ArrayList<String>();

Note I'm importing the ArrayList specifically. I could have done

import java.util.*; 

But you generally want to avoid large wildcard imports to avoid the problem of collisions between packages.

Uncaught ReferenceError: function is not defined with onclick

Make sure you are using Javascript module or not?! if using js6 modules your html events attributes won't work. in that case you must bring your function from global scope to module scope. Just add this to your javascript file: window.functionName= functionName;

example:

<h1 onClick="functionName">some thing</h1>

Best way to return a value from a python script

If you want your script to return values, just do return [1,2,3] from a function wrapping your code but then you'd have to import your script from another script to even have any use for that information:

Return values (from a wrapping-function)

(again, this would have to be run by a separate Python script and be imported in order to even do any good):

import ...
def main():
    # calculate stuff
    return [1,2,3]

Exit codes as indicators

(This is generally just good for when you want to indicate to a governor what went wrong or simply the number of bugs/rows counted or w/e. Normally 0 is a good exit and >=1 is a bad exit but you could inter-prate them in any way you want to get data out of it)

import sys
# calculate and stuff
sys.exit(100)

And exit with a specific exit code depending on what you want that to tell your governor. I used exit codes when running script by a scheduling and monitoring environment to indicate what has happened.

(os._exit(100) also works, and is a bit more forceful)

Stdout as your relay

If not you'd have to use stdout to communicate with the outside world (like you've described). But that's generally a bad idea unless it's a parser executing your script and can catch whatever it is you're reporting to.

import sys
# calculate stuff
sys.stdout.write('Bugs: 5|Other: 10\n')
sys.stdout.flush()
sys.exit(0)

Are you running your script in a controlled scheduling environment then exit codes are the best way to go.

Files as conveyors

There's also the option to simply write information to a file, and store the result there.

# calculate
with open('finish.txt', 'wb') as fh:
    fh.write(str(5)+'\n')

And pick up the value/result from there. You could even do it in a CSV format for others to read simplistically.

Sockets as conveyors

If none of the above work, you can also use network sockets locally *(unix sockets is a great way on nix systems). These are a bit more intricate and deserve their own post/answer. But editing to add it here as it's a good option to communicate between processes. Especially if they should run multiple tasks and return values.

Could not find a base address that matches scheme https for the endpoint with binding WebHttpBinding. Registered base address schemes are [http]

You would need to enable https binding on server side. IISExpress in this case. Select Properties on website project in solution explorer (not double click). In the properties pane then you need to enable SSL.

How can I prevent the TypeError: list indices must be integers, not tuple when copying a python list to a numpy array?

np.append needs the array as the first argument and the list you want to append as the second:

mean_data = np.append(mean_data, [ur, ua, np.mean(data[samepoints,-1])])

'DataFrame' object has no attribute 'sort'

sort() was deprecated for DataFrames in favor of either:

sort() was deprecated (but still available) in Pandas with release 0.17 (2015-10-09) with the introduction of sort_values() and sort_index(). It was removed from Pandas with release 0.20 (2017-05-05).

Selenium Error - The HTTP request to the remote WebDriver timed out after 60 seconds

Had same issue with Firefox. I switched over to Chrome with options and all has been fine since.

ChromeOptions options = new ChromeOptions();
 options.AddArgument("no-sandbox");

 ChromeDriver driver = new ChromeDriver(ChromeDriverService.CreateDefaultService(), options, TimeSpan.FromMinutes(3));
 driver.Manage().Timeouts().PageLoad.Add(System.TimeSpan.FromSeconds(30));

CSS - Expand float child DIV height to parent's height

I have recently done this on my website using jQuery. The code calculates the height of the tallest div and sets the other divs to the same height. Here's the technique:

http://www.broken-links.com/2009/01/20/very-quick-equal-height-columns-in-jquery/

I don't believe height:100% will work, so if you don't explicitly know the div heights I don't think there is a pure CSS solution.

How to add directory to classpath in an application run profile in IntelliJ IDEA?

It appears that IntelliJ 11 has changed the method, and the checked answer no longer works for me. In case anyone else arrives here via a search engine, here's how I solved it in IntelliJ 11:

  1. Go to the Project Structure, click on Modules, and click on your Module
  2. Choose the "Dependencies" tab
  3. Click the "+" button on the right-hand side and select "Jars or directories..."
  4. Add the directory(ies) you want (note you can multi-select) and click OK
  5. In the dialog that comes up, select "classes" and NOT "jar directory"
  6. Make sure you're using that Module in your run target

Note that step 5 seems to be the key difference. If you select "jar directory" it will look exactly the same in the IDE but won't include the path at runtime. There appears to be no way to determine whether you've previously selected "classes" or "jar directory" after the fact.

Using Node.js require vs. ES6 import/export

I personally use import because, we can import the required methods, members by using import.

import {foo, bar} from "dep";

FileName: dep.js

export foo function(){};
export const bar = 22

Credit goes to Paul Shan. More info.

How can I check if a var is a string in JavaScript?

My personal approach, which seems to work for all cases, is testing for the presence of members that will all only be present for strings.

function isString(x) {
    return (typeof x == 'string' || typeof x == 'object' && x.toUpperCase && x.substr && x.charAt && x.trim && x.replace ? true : false);
}

See: http://jsfiddle.net/x75uy0o6/

I'd like to know if this method has flaws, but it has served me well for years.

How to Import 1GB .sql file to WAMP/phpmyadmin

I suspect you will be able to import 1 GB file through phpmyadmin But you can try by increasing the following value in php.ini and restart the wamp.

post_max_size=1280M
upload_max_filesize=1280M
max_execution_time = 300 //increase time as per your server requirement. 

You can also try below command from command prompt, your path may be different as per your MySQL installation.

C:\wamp\bin\mysql\mysql5.5.24\bin\mysql.exe -u root -p db_name < C:\some_path\your_sql_file.sql

You should increase the max_allowed_packet of mysql in my.ini to avoid MySQL server gone away error, something like this

max_allowed_packet = 100M

How to prevent Google Colab from disconnecting?

Well I am not a python guy nor I know what is the actual use of this 'Colab', I use it as a build system lol. And I used to setup ssh forwarding in it then put this code and just leave it running and yeah it works.

import getpass
authtoken = getpass.getpass()

What's the difference between :: (double colon) and -> (arrow) in PHP?

The difference between static and instantiated methods and properties seem to be one of the biggest obstacles to those just starting out with OOP PHP in PHP 5.

The double colon operator (which is called the Paamayim Nekudotayim from Hebrew - trivia) is used when calling an object or property from a static context. This means an instance of the object has not been created yet.

The arrow operator, conversely, calls methods or properties that from a reference of an instance of the object.

Static methods can be especially useful in object models that are linked to a database for create and delete methods, since you can set the return value to the inserted table id and then use the constructor to instantiate the object by the row id.

How do I automatically scroll to the bottom of a multiline text box?

Try to add the suggested code to the TextChanged event:

private void textBox1_TextChanged(object sender, EventArgs e)
{
  textBox1.SelectionStart = textBox1.Text.Length;
  textBox1.ScrollToCaret();
}

node.js hash string?

Even if the hash is not for security, you can use sha instead of md5. In my opinion, the people should forget about md5 for now, it's in the past!

The normal nodejs sha256 is deprecated. So, you have two alternatives for now:

var shajs = require('sha.js')  - https://www.npmjs.com/package/sha.js (used by Browserify)

var hash = require('hash.js')  - https://github.com/indutny/hash.js

I prefer using shajs instead of hash, because I consider sha the best hash function nowadays and you don't need a different hash function for now. So to get some hash in hex you should do something like the following:

sha256.update('hello').digest('hex')

How do I get the current mouse screen coordinates in WPF?

If you try a lot of these answers out on different resolutions, computers with multiple monitors, etc. you may find that they don't work reliably. This is because you need to use a transform to get the mouse position relative to the current screen, not the entire viewing area which consists of all your monitors. Something like this...(where "this" is a WPF window).

var transform = PresentationSource.FromVisual(this).CompositionTarget.TransformFromDevice;
var mouse = transform.Transform(GetMousePosition());

public System.Windows.Point GetMousePosition()
{
    var point = Forms.Control.MousePosition;
    return new Point(point.X, point.Y);
}

Best way to store chat messages in a database?

If you can avoid the need for concurrent writes to a single file, it sounds like you do not need a database to store the chat messages.

Just append the conversation to a text file (1 file per user\conversation). and have a directory/ file structure

Here's a simplified view of the file structure:

chat-1-bob.txt
        201101011029, hi
        201101011030, fine thanks.

chat-1-jen.txt
        201101011030, how are you?
        201101011035, have you spoken to bill recently?

chat-2-bob.txt
        201101021200, hi
        201101021222, about 12:22
chat-2-bill.txt
        201101021201, Hey Bob,
        201101021203, what time do you call this?

You would then only need to store the userid, conversation id (guid ?) & a reference to the file name.

I think you will find it hard to get a more simple scaleable solution.

You can use LOAD_FILE to get the data too see: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html

If you have a requirement to rebuild a conversation you will need to put a value (date time) alongside your sent chat message (in the file) to allow you to merge & sort the files, but at this point it is probably a good idea to consider using a database.

Relationship between hashCode and equals method in Java

The contract is that if obj1.equals(obj2) then obj1.hashCode() == obj2.hashCode() , it is mainly for performance reasons, as maps are mainly using hashCode method to compare entries keys.

How do I create a right click context menu in Java Swing?

You are probably manually calling setVisible(true) on the menu. That can cause some nasty buggy behavior in the menu.

The show(Component, int x, int x) method handles all of the things you need to happen, (Highlighting things on mouseover and closing the popup when necessary) where using setVisible(true) just shows the menu without adding any additional behavior.

To make a right click popup menu simply create a JPopupMenu.

class PopUpDemo extends JPopupMenu {
    JMenuItem anItem;
    public PopUpDemo() {
        anItem = new JMenuItem("Click Me!");
        add(anItem);
    }
}

Then, all you need to do is add a custom MouseListener to the components you would like the menu to popup for.

class PopClickListener extends MouseAdapter {
    public void mousePressed(MouseEvent e) {
        if (e.isPopupTrigger())
            doPop(e);
    }

    public void mouseReleased(MouseEvent e) {
        if (e.isPopupTrigger())
            doPop(e);
    }

    private void doPop(MouseEvent e) {
        PopUpDemo menu = new PopUpDemo();
        menu.show(e.getComponent(), e.getX(), e.getY());
    }
}

// Then on your component(s)
component.addMouseListener(new PopClickListener());

Of course, the tutorials have a slightly more in-depth explanation.

Note: If you notice that the popup menu is appearing way off from where the user clicked, try using the e.getXOnScreen() and e.getYOnScreen() methods for the x and y coordinates.

How to configure CORS in a Spring Boot + Spring Security application?

@Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**").allowedOrigins("*").allowedMethods("*");
            }
        };
    }

How to add custom Http Header for C# Web Service Client consuming Axis 1.4 Web service

Here is what worked for me:

protected override System.Net.WebRequest GetWebRequest(Uri uri)
{
        HttpWebRequest request;
        request = (HttpWebRequest)base.GetWebRequest(uri);
        NetworkCredential networkCredentials =
        Credentials.GetCredential(uri, "Basic");
        if (networkCredentials != null)
        {
            byte[] credentialBuffer = new UTF8Encoding().GetBytes(
            networkCredentials.UserName + ":" +
            networkCredentials.Password);
            request.Headers["Authorization"] =
            "Basic " + Convert.ToBase64String(credentialBuffer);
            request.Headers["Cookie"] = "BCSI-CS-2rtyueru7546356=1";
            request.Headers["Cookie2"] = "$Version=1";
        }
        else
        {
            throw new ApplicationException("No network credentials");
        }
        return request;
}

Don't forget to set this property:

service.Credentials = new NetworkCredential("username", "password");  

Cookie and Cookie2 are set in header because java service was not accepting the request and I was getting Unauthorized error.

How do I use a regex in a shell script?

To complement the existing helpful answers:

Using Bash's own regex-matching operator, =~, is a faster alternative in this case, given that you're only matching a single value already stored in a variable:

set -- '12-34-5678' # set $1 to sample value

kREGEX_DATE='^[0-9]{2}[-/][0-9]{2}[-/][0-9]{4}$' # note use of [0-9] to avoid \d
[[ $1 =~ $kREGEX_DATE ]]
echo $? # 0 with the sample value, i.e., a successful match

Note, however, that the caveat re using flavor-specific regex constructs such as \d equally applies: While =~ supports EREs (extended regular expressions), it also supports the host platform's specific extension - it's a rare case of Bash's behavior being platform-dependent.

To remain portable (in the context of Bash), stick to the POSIX ERE specification.

Note that =~ even allows you to define capture groups (parenthesized subexpressions) whose matches you can later access through Bash's special ${BASH_REMATCH[@]} array variable.

Further notes:

  • $kREGEX_DATE is used unquoted, which is necessary for the regex to be recognized as such (quoted parts would be treated as literals).

  • While not always necessary, it is advisable to store the regex in a variable first, because Bash has trouble with regex literals containing \.

    • E.g., on Linux, where \< is supported to match word boundaries, [[ 3 =~ \<3 ]] && echo yes doesn't work, but re='\<3'; [[ 3 =~ $re ]] && echo yes does.
  • I've changed variable name REGEX_DATE to kREGEX_DATE (k signaling a (conceptual) constant), so as to ensure that the name isn't an all-uppercase name, because all-uppercase variable names should be avoided to prevent conflicts with special environment and shell variables.

Laravel 5.2 - Use a String as a Custom Primary Key for Eloquent Table becomes 0

On the model set $incrementing to false

public $incrementing = false;

This will stop it from thinking it is an auto increment field.

Laravel Docs - Eloquent - Defining Models

Optional Parameters in Go?

You can use a struct which includes the parameters:

type Params struct {
  a, b, c int
}

func doIt(p Params) int {
  return p.a + p.b + p.c 
}

// you can call it without specifying all parameters
doIt(Params{a: 1, c: 9})

How to use mod operator in bash?

You must put your mathematical expressions inside $(( )).

One-liner:

for i in {1..600}; do wget http://example.com/search/link$(($i % 5)); done;

Multiple lines:

for i in {1..600}; do
    wget http://example.com/search/link$(($i % 5))
done

Angular HttpPromise: difference between `success`/`error` methods and `then`'s arguments

Just for completion, here is a code example indicating the differences:

success \ error:

$http.get('/someURL')
.success(function(data, status, header, config) {
    // success handler
})
.error(function(data, status, header, config) {
    // error handler
});

then:

$http.get('/someURL')
.then(function(response) {
    // success handler
}, function(response) {
    // error handler
})
.then(function(response) {
    // success handler
}, function(response) {
    // error handler
})
.then(function(response) {
    // success handler
}, function(response) {
    // error handler
}).

How to Execute stored procedure from SQL Plus?

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

var z number

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

print z

How do you join tables from two different SQL Server instances in one SQL query

You can create a linked server and reference the table in the other instance using its fully qualified Server.Catalog.Schema.Table name.

How to list only top level directories in Python?

Note that, instead of doing os.listdir(os.getcwd()), it's preferable to do os.listdir(os.path.curdir). One less function call, and it's as portable.

So, to complete the answer, to get a list of directories in a folder:

def listdirs(folder):
    return [d for d in os.listdir(folder) if os.path.isdir(os.path.join(folder, d))]

If you prefer full pathnames, then use this function:

def listdirs(folder):
    return [
        d for d in (os.path.join(folder, d1) for d1 in os.listdir(folder))
        if os.path.isdir(d)
    ]

How to DROP multiple columns with a single ALTER TABLE statement in SQL Server?

For MySQL (ver 5.6), you cannot do multiple column drop with one single drop-statement but rather multiple drop-statements:

mysql> alter table test2 drop column (c1,c2,c3);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(c1,c2,c3)' at line 1
mysql> alter table test2 drop column c1,c2,c3;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'c2,c3' at line 1
mysql> alter table test2 drop column c1, drop column c2, drop c3;
Query OK, 0 rows affected (0.64 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> 

BTW, drop <col_name> is shorthanded for drop column <col_name> as you can see from drop c3 above.

Where to place $PATH variable assertions in zsh?

tl;dr version: use ~/.zshrc

And read the man page to understand the differences between:

~/.zshrc, ~/.zshenv and ~/.zprofile.


Regarding my comment

In my comment attached to the answer kev gave, I said:

This seems to be incorrect - /etc/profile isn't listed in any zsh documentation I can find.

This turns out to be partially incorrect: /etc/profile may be sourced by zsh. However, this only occurs if zsh is "invoked as sh or ksh"; in these compatibility modes:

The usual zsh startup/shutdown scripts are not executed. Login shells source /etc/profile followed by $HOME/.profile. If the ENV environment variable is set on invocation, $ENV is sourced after the profile scripts. The value of ENV is subjected to parameter expansion, command substitution, and arithmetic expansion before being interpreted as a pathname. [man zshall, "Compatibility"].

The ArchWiki ZSH link says:

At login, Zsh sources the following files in this order:
/etc/profile
This file is sourced by all Bourne-compatible shells upon login

This implys that /etc/profile is always read by zsh at login - I haven't got any experience with the Arch Linux project; the wiki may be correct for that distribution, but it is not generally correct. The information is incorrect compared to the zsh manual pages, and doesn't seem to apply to zsh on OS X (paths in $PATH set in /etc/profile do not make it to my zsh sessions).



To address the question:

where exactly should I be placing my rvm, python, node etc additions to my $PATH?

Generally, I would export my $PATH from ~/.zshrc, but it's worth having a read of the zshall man page, specifically the "STARTUP/SHUTDOWN FILES" section - ~/.zshrc is read for interactive shells, which may or may not suit your needs - if you want the $PATH for every zsh shell invoked by you (both interactive and not, both login and not, etc), then ~/.zshenv is a better option.

Is there a specific file I should be using (i.e. .zshenv which does not currently exist in my installation), one of the ones I am currently using, or does it even matter?

There's a bunch of files read on startup (check the linked man pages), and there's a reason for that - each file has it's particular place (settings for every user, settings for user-specific, settings for login shells, settings for every shell, etc).
Don't worry about ~/.zshenv not existing - if you need it, make it, and it will be read.

.bashrc and .bash_profile are not read by zsh, unless you explicitly source them from ~/.zshrc or similar; the syntax between bash and zsh is not always compatible. Both .bashrc and .bash_profile are designed for bash settings, not zsh settings.

'typeid' versus 'typeof' in C++

The primary difference between the two is the following

  • typeof is a compile time construct and returns the type as defined at compile time
  • typeid is a runtime construct and hence gives information about the runtime type of the value.

typeof Reference: http://www.delorie.com/gnu/docs/gcc/gcc_36.html

typeid Reference: https://en.wikipedia.org/wiki/Typeid

JUnit tests pass in Eclipse but fail in Maven Surefire

You don't need to inject a DataSource in the JpaTransactionManager since the EntityManagerFactory already has a datasource. Try the following:

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
   <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

jQuery: Performing synchronous AJAX requests

You're using the ajax function incorrectly. Since it's synchronous it'll return the data inline like so:

var remote = $.ajax({
    type: "GET",
    url: remote_url,
    async: false
}).responseText;

How to read numbers separated by space using scanf

It should be as simple as using a list of receiving variables:

scanf("%i %i %i", &var1, &var2, &var3);

Rerouting stdin and stdout from C

Why use freopen()? The C89 specification has the answer in one of the endnotes for the section on <stdio.h>:

116. The primary use of the freopen function is to change the file associated with a standard text stream (stderr, stdin, or stdout), as those identifiers need not be modifiable lvalues to which the value returned by the fopen function may be assigned.

freopen is commonly misused, e.g. stdin = freopen("newin", "r", stdin);. This is no more portable than fclose(stdin); stdin = fopen("newin", "r");. Both expressions attempt to assign to stdin, which is not guaranteed to be assignable.

The right way to use freopen is to omit the assignment: freopen("newin", "r", stdin);

rawQuery(query, selectionArgs)

Maybe this can help you

Cursor c = db.rawQuery("query",null);
int id[] = new int[c.getCount()];
int i = 0;
if (c.getCount() > 0) 
{               
    c.moveToFirst();
    do {
        id[i] = c.getInt(c.getColumnIndex("field_name"));
        i++;
    } while (c.moveToNext());
    c.close();
}

What is the point of WORKDIR on Dockerfile?

Beware of using vars as the target directory name for WORKDIR - doing that appears to result in a "cannot normalize nothing" fatal error. IMO, it's also worth pointing out that WORKDIR behaves in the same way as mkdir -p <path> i.e. all elements of the path are created if they don't exist already.

UPDATE: I encountered the variable related problem (mentioned above) whilst running a multi-stage build - it now appears that using a variable is fine - if it (the variable) is "in scope" e.g. in the following, the 2nd WORKDIR reference fails ...

FROM <some image>
ENV varname varval
WORKDIR $varname

FROM <some other image>
WORKDIR $varname

whereas, it succeeds in this ...

FROM <some image>
ENV varname varval
WORKDIR $varname

FROM <some other image>
ENV varname varval
WORKDIR $varname

.oO(Maybe it's in the docs & I've missed it)

How do I append one string to another in Python?

Basically, no difference. The only consistent trend is that Python seems to be getting slower with every version... :(


List

%%timeit
x = []
for i in range(100000000):  # xrange on Python 2.7
    x.append('a')
x = ''.join(x)

Python 2.7

1 loop, best of 3: 7.34 s per loop

Python 3.4

1 loop, best of 3: 7.99 s per loop

Python 3.5

1 loop, best of 3: 8.48 s per loop

Python 3.6

1 loop, best of 3: 9.93 s per loop


String

%%timeit
x = ''
for i in range(100000000):  # xrange on Python 2.7
    x += 'a'

Python 2.7:

1 loop, best of 3: 7.41 s per loop

Python 3.4

1 loop, best of 3: 9.08 s per loop

Python 3.5

1 loop, best of 3: 8.82 s per loop

Python 3.6

1 loop, best of 3: 9.24 s per loop

Access parent DataContext from DataTemplate

the issue is that a DataTemplate isn't part of an element its applied to it.

this means if you bind to the template you're binding to something that has no context.

however if you put a element inside the template then when that element is applied to the parent it gains a context and the binding then works

so this will not work

<DataTemplate >
    <DataTemplate.Resources>
        <CollectionViewSource x:Key="projects" Source="{Binding Projects}" >

but this works perfectly

<DataTemplate >
    <GroupBox Header="Projects">
        <GroupBox.Resources>
            <CollectionViewSource x:Key="projects" Source="{Binding Projects}" >

because after the datatemplate is applied the groupbox is placed in the parent and will have access to its Context

so all you have to do is remove the style from the template and move it into an element in the template

note that the context for a itemscontrol is the item not the control ie ComboBoxItem for ComboBox not the ComboBox itself in which case you should use the controls ItemContainerStyle instead

Mismatched anonymous define() module

Be aware that some browser extensions can add code to the pages. In my case I had an "Emmet in all textareas" plugin that messed up with my requireJs. Make sure that no extra code is beign added to your document by inspecting it in the browser.

git checkout all the files

If you are at the root of your working directory, you can do git checkout -- . to check-out all files in the current HEAD and replace your local files.

You can also do git reset --hard to reset your working directory and replace all changes (including the index).

What is the difference between a static method and a non-static method?

- First we must know that the diff bet static and non static methods 
is differ from static and non static variables : 

- this code explain static method - non static method and what is the diff 

    public class MyClass {
        static {
            System.out.println("this is static routine ... ");

        }
          public static void foo(){
            System.out.println("this is static method ");
        }

        public void blabla(){

         System.out.println("this is non static method ");
        }

        public static void main(String[] args) {

           /* ***************************************************************************  
            * 1- in static method you can implement the method inside its class like :  *       
            * you don't have to make an object of this class to implement this method   *      
            * MyClass.foo();          // this is correct                                *     
            * MyClass.blabla();       // this is not correct because any non static     *
            * method you must make an object from the class to access it like this :    *            
            * MyClass m = new MyClass();                                                *     
            * m.blabla();                                                               *    
            * ***************************************************************************/

            // access static method without make an object 
            MyClass.foo();

            MyClass m = new MyClass();
            // access non static method via make object 
            m.blabla();
            /* 
              access static method make a warning but the code run ok 
               because you don't have to make an object from MyClass 
               you can easily call it MyClass.foo(); 
            */
            m.foo();
        }    
    }
    /* output of the code */
    /*
    this is static routine ... 
    this is static method 
    this is non static method 
    this is static method
    */

 - this code explain static method - non static Variables and what is the diff 


     public class Myclass2 {

                // you can declare static variable here : 
                // or you can write  int callCount = 0; 
                // make the same thing 
                //static int callCount = 0; = int callCount = 0;
                static int callCount = 0;    

                public void method() {
                    /********************************************************************* 
                    Can i declare a static variable inside static member function in Java?
                    - no you can't 
                    static int callCount = 0;  // error                                                   
                    ***********************************************************************/
                /* static variable */
                callCount++;
                System.out.println("Calls in method (1) : " + callCount);
                }

                public void method2() {
                int callCount2 = 0 ; 
                /* non static variable */   
                callCount2++;
                System.out.println("Calls in method (2) : " + callCount2);
                }


            public static void main(String[] args) {
             Myclass2 m = new Myclass2();
             /* method (1) calls */
             m.method(); 
             m.method();
             m.method();
             /* method (2) calls */
             m.method2();
             m.method2();
             m.method2();
            }

        }
        // output 

        // Calls in method (1) : 1
        // Calls in method (1) : 2
        // Calls in method (1) : 3
        // Calls in method (2) : 1
        // Calls in method (2) : 1
        // Calls in method (2) : 1 

How to "grep" out specific line ranges of a file

The following command will do what you asked for "extract the lines between 1234 and 5555" in someFile.

sed -n '1234,5555p' someFile

Format string to a 3 digit number

 string.Format("{0:000}", myString);

Join String list elements with a delimiter in one step

You can use the StringUtils.join() method of Apache Commons Lang:

String join = StringUtils.join(joinList, "+");

React Error: Target Container is not a DOM Element

Also, the best practice of moving your <script></script> to the bottom of the html file fixes this too.

GCM with PHP (Google Cloud Messaging)

Also you can try this piece of code, source:

<?php
    define("GOOGLE_API_KEY", "AIzaSyCJiVkatisdQ44rEM353PFGbia29mBVscA");
    define("GOOGLE_GCM_URL", "https://android.googleapis.com/gcm/send");

    function send_gcm_notify($reg_id, $message) {
        $fields = array(
            'registration_ids'  => array( $reg_id ),
            'data'              => array( "message" => $message ),
        );

        $headers = array(
            'Authorization: key=' . GOOGLE_API_KEY,
            'Content-Type: application/json'
        );

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, GOOGLE_GCM_URL);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));

        $result = curl_exec($ch);
        if ($result === FALSE) {
            die('Problem occurred: ' . curl_error($ch));
        }

        curl_close($ch);
        echo $result;
    }

    $reg_id = "APA91bHuSGES.....nn5pWrrSz0dV63pg";
    $msg = "Google Cloud Messaging working well";

    send_gcm_notify($reg_id, $msg);

What is the C# equivalent of friend?

There's no direct equivalent of "friend" - the closest that's available (and it isn't very close) is InternalsVisibleTo. I've only ever used this attribute for testing - where it's very handy!

Example: To be placed in AssemblyInfo.cs

[assembly: InternalsVisibleTo("OtherAssembly")]

How to iterate through SparseArray?

The answer is no because SparseArray doesn't provide it. As pst put it, this thing doesn't provide any interfaces.

You could loop from 0 - size() and skip values that return null, but that is about it.

As I state in my comment, if you need to iterate use a Map instead of a SparseArray. For example, use a TreeMap which iterates in order by the key.

TreeMap<Integer, MyType>

Callback when DOM is loaded in react.js

I applied componentDidUpdate to table to have all columns same height. it works same as on $(window).load() in jquery.

eg:

componentDidUpdate: function() {
        $(".tbl-tr").height($(".tbl-tr ").height());
    }

Passing string to a function in C - with or without pointers?

An array is a pointer. It points to the start of a sequence of "objects".

If we do this: ìnt arr[10];, then arr is a pointer to a memory location, from which ten integers follow. They are uninitialised, but the memory is allocated. It is exactly the same as doing int *arr = new int[10];.

SQLAlchemy equivalent to SQL "LIKE" statement

Using PostgreSQL like (see accepted answer above) somehow didn't work for me although cases matched, but ilike (case insensisitive like) does.

Update Jenkins from a war file

I use this groovy script to download new war file

import java.util.concurrent.atomic.AtomicInteger

class ThreadHelper{
    static done = false;
    static starttime = System.currentTimeMillis()
    static synchronized printx (message) {    printf ("%5s seconds: %20s",(System.currentTimeMillis()-starttime)/1000.0 , message); println("") }
    def download(address)
    {
    def filename = new File(System.getenv()['CI_HOME'] + '/' + address.tokenize("/")[-1])
    println(filename.getCanonicalPath())
    def file = new FileOutputStream(filename)
    def out = new BufferedOutputStream(file)
    out << new URL(address).openStream()
    out.close()
    done=true;
    }

}

println("executing from ... "+ new File(".").getCanonicalPath())

def counter = new AtomicInteger();
    th = Thread.start {
    while(!ThreadHelper.done) {
    sleep 1000
    counter.incrementAndGet()
    print '.'
    }
}

th2 = Thread.start { new ThreadHelper().download("http://mirrors.jenkins-ci.org/war/latest/jenkins.war") }
th.join()
th2.join()

ThreadHelper.printx('done')

And another script shutsdown tomcat - copies the war and restarts it

We host it on windows 2008 and tomcat, I use sc query, sc config, sc stop, sc start to manage windows services

    set warname=jenkins

if '%name%' == 'trak' set warname=trak

pushd .
if '%name%'=='' goto badname
if '%warname%'=='' goto badname

if '%ci_home%'=='' goto badcihome

REM =====================================================
REM stop windows service
sc stop %name%

REM sleep for 5 seconds see http:\\stackoverflow.com\questions\1672338\how-to-sleep-for-5-seconds-in-windowss-command-prompt-or-dos
ping 1.1.1.1 -n 1 -w 3000 > nul

rem replace forward slash with backward slash
set tomcat_dir=%ci_home:/=\%\instances\tomcat7-%name%

REM Create sub directory called bak-yymmdd-hhmmss
REM where yymmdd-hhmmss is a date-time stamp like 120601-142907

set hh=%time:~0,2%

REM Since there is no leading zero for times before 10 am, have to put in
REM a zero when this is run before 10 am.

if "%time:~0,1%"==" " set hh=0%hh:~1,1%

set yymmdd_hhmmss=%date:~12,2%%date:~4,2%%date:~7,2%-%hh%%time:~3,2%%time:~6,2%

set backupdir=bak-%yymmdd_hhmmss%

REM =====================================================
md %tomcat_dir%\logs\%backupdir%

cd %tomcat_dir%\logs

dir bak*
echo "nothing-to-log" >> force.log

REM move command will fail if there is nothing to move hence the force log statement above

call move *.* %backupdir%

REM =====================================================
rmdir %tomcat_dir%\webapps\%name% /q/s

echo f|xcopy %ci_home%\%warname%.war %tomcat_dir%\webapps\%name%.war /y

REM TODO===== something about jenkins plugins

REM =====================================================
cd "%tomcat_dir%\bin"
call catalina version

echo =====================================================
echo ====== removing %name%
call service remove %name%

echo =====================================================
echo ====== installing %name%
call service install %name%

echo on

REM setting service to start automatically, note that space before the word auto IS REQUIRED
sc config %name% start= auto

REM =====================================================
sc start %name%

popd

exit 0

goto done

:badname
echo 'name required - this will be used as windows service name as well'
pause
exit 1

:badcihome
echo 'CI home env var required - ci_home'
pause
exit 1

:done

I need to convert an int variable to double

Either use casting as others have already said, or multiply one of the int variables by 1.0:

double firstSolution = ((1.0* b1 * a22 - b2 * a12) / (a11 * a22 - a12 * a21));

Specifying width and height as percentages without skewing photo proportions in HTML

Try use scale property in css3:

75% of original:

-moz-transform:scale(0.75);
-webkit-transform:scale(0.75);
transform:scale(0.75);

50% of original:

-moz-transform:scale(0.5);
-webkit-transform:scale(0.5);
transform:scale(0.5);

Giving my function access to outside variable

$myArr = array();

function someFuntion(array $myArr) {
    $myVal = //some processing here to determine value of $myVal
    $myArr[] = $myVal;

    return $myArr;
}

$myArr = someFunction($myArr);

IntelliJ Organize Imports

ALT+ENTER was far from eclipse habit ,in IDEA for me mouse over did not work , so in setting>IDESetting>Keymap>Show intention actions and quick-fixes I changed it to mouse left click , It did not support mouse over! but mouse left click was OK and closest to my intention.

Count Rows in Doctrine QueryBuilder

For people who are using only Doctrine DBAL and not the Doctrine ORM, they will not be able to access the getQuery() method because it doesn't exists. They need to do something like the following.

$qb = new QueryBuilder($conn);
$count = $qb->select("count(id)")->from($tableName)->execute()->fetchColumn(0);

how to make log4j to write to the console as well

Your root logger definition is a bit confused. See the log4j documentation.

This is a standard Java properties file, which means that lines are treated as key=value pairs. Your second log4j.rootLogger line is overwriting the first, which explains why you aren't seeing anything on the console appender.

You need to merge your two rootLogger definitions into one. It looks like you're trying to have DEBUG messages go to the console and INFO messages to the file. The root logger can only have one level, so you need to change your configuration so that the appenders have appropriate levels.

While I haven't verified that this is correct, I'd guess it'll look something like this:

log4j.rootLogger=DEBUG,console,file
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.file=org.apache.log4j.RollingFileAppender

Note that you also have an error in casing - you have console lowercase in one place and in CAPS in another.

How do I set the default Java installation/runtime (Windows)?

an alterable way to run an .jar app is create an .bat cmd for it. for example, you have jre10 and jre8 installed on your pc,and jre10 is your default jre. but your jar is specified to work with jre8,following cmd will work:

"C:\Program Files\Java\jre1.8.0_181\bin\java.exe" -jar JabRef-4.3.1.jar

What to use instead of "addPreferencesFromResource" in a PreferenceActivity?

My approach is very close to Garret Wilson's (thanks, I voted you up ;)

In addition it provides downward compatibility with Android < 3.

I just recognized that my solution is even closer to the one by Kevin Remo. It's just a wee bit cleaner (as it does not rely on the "expection" antipattern).

public class MyPreferenceActivity extends PreferenceActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB) {
            onCreatePreferenceActivity();
        } else {
            onCreatePreferenceFragment();
        }
    }

    /**
     * Wraps legacy {@link #onCreate(Bundle)} code for Android < 3 (i.e. API lvl
     * < 11).
     */
    @SuppressWarnings("deprecation")
    private void onCreatePreferenceActivity() {
        addPreferencesFromResource(R.xml.preferences);
    }

    /**
     * Wraps {@link #onCreate(Bundle)} code for Android >= 3 (i.e. API lvl >=
     * 11).
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    private void onCreatePreferenceFragment() {
        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, new MyPreferenceFragment ())
                .commit();
    }
}

For a "real" (but more complex) example see NusicPreferencesActivity and NusicPreferencesFragment.

Why GDB jumps unpredictably between lines and prints variables as "<value optimized out>"?

The compiler will start doing very clever things with optimisations turned on. The debugger will show the code jumping forward and backwards alot due to the optimized way variables are stored in registers. This is probably the reason why you can't set your variable (or in some cases see its value) as it has been cleverly distributed between registers for speed, rather than having a direct memory location that the debugger can access.

Compile without optimisations?

How to set up file permissions for Laravel?

First of your answer is.

sudo chmod -R 777/775 /path/project_folder

Now You need to understand permissions and options in ubuntu.

  • chmod - You can set permissions.
  • chown - You can set the ownership of files and directories.
  • 777 - read/write/execute.
  • 775 - read/execute.

Could not load file or assembly System.Web.Http.WebHost after published to Azure web site

For me worked adding the following section to web.config file:

<configuration>
...
    <runtime>
    ...
        <dependentAssembly>
            <assemblyIdentity name="System.Web.Http.WebHost" publicKeyToken="31bf3856ad364e35" culture="neutral" />
            <bindingRedirect oldVersion="0.0.0.0-5.1.0.0" newVersion="5.1.0.0" />
        </dependentAssembly>
    ...
    </runtime>
...
</configuration>

This example stands for MVC 5.1. Hope it will help someone to resolve such issue.

Error: EACCES: permission denied

LUBUNTU 19.10 / Same issue running: $ npm start

dump: Error: EACCES: permission denied, open '/home/simon/xxx/pagebuilder/resources/scripts/registration/node_modules/.cache/@babel/register/.babel.7.4.0.development.json' at Object.fs.openSync (fs.js:646:18) at Object.fs.writeFileSync (fs.js:1299:33) at save (/home/simon/xxx/pagebuilder/resources/scripts/registration/node_modules/@babel/register/lib/cache.js:52:15) at _combinedTickCallback (internal/process/next_tick.js:132:7) at process._tickCallback (internal/process/next_tick.js:181:9) at Function.Module.runMain (module.js:696:11) at Object. (/home/simon/xxxx/pagebuilder/resources/scripts/registration/node_modules/@babel/node/lib/_babel-node.js:234:23) at Module._compile (module.js:653:30) at Object.Module._extensions..js (module.js:664:10) at Module.load (module.js:566:32)

Looks like my default user (administrator) didn't have rights on node-module directories.

This fixed it for me!

$ sudo chmod a+w node_modules -R ## from project root

fatal: bad default revision 'HEAD'

Make sure branch "master" exists! It's not just a name apparently.

I got this error after creating a blank bare repo, pushing a branch named "dev" to it, and trying to use git log in the bare repo. Interestingly, git branch knows that dev is the only branch existing (so I think this is a git bug).

Solution: I repeated the procedure, this time having renamed "dev" to "master" on the working repo before pushing to the bare repo. Success!

When is JavaScript synchronous?

To someone who really understands how JS works this question might seem off, however most people who use JS do not have such a deep level of insight (and don't necessarily need it) and to them this is a fairly confusing point, I will try to answer from that perspective.

JS is synchronous in the way its code is executed. each line only runs after the line before it has completed and if that line calls a function after that is complete etc...

The main point of confusion arises from the fact that your browser is able to tell JS to execute more code at anytime (similar to how you can execute more JS code on a page from the console). As an example JS has Callback functions who's purpose is to allow JS to BEHAVE asynchronously so further parts of JS can run while waiting for a JS function that has been executed (I.E. a GET call) to return back an answer, JS will continue to run until the browser has an answer at that point the event loop (browser) will execute the JS code that calls the callback function.

Since the event loop (browser) can input more JS to be executed at any point in that sense JS is asynchronous (the primary things that will cause a browser to input JS code are timeouts, callbacks and events)

I hope this is clear enough to be helpful to somebody.

Starting of Tomcat failed from Netbeans

I had the same problem but none of the answers above worked. The solution for me was to restore the Manager web application that is bundled with Tomcat.

SQLAlchemy: print the actual query

This code is based on brilliant existing answer from @bukzor. I just added custom render for datetime.datetime type into Oracle's TO_DATE().

Feel free to update code to suit your database:

import decimal
import datetime

def printquery(statement, bind=None):
    """
    print a query, with values filled in
    for debugging purposes *only*
    for security, you should always separate queries from their values
    please also note that this function is quite slow
    """
    import sqlalchemy.orm
    if isinstance(statement, sqlalchemy.orm.Query):
        if bind is None:
            bind = statement.session.get_bind(
                    statement._mapper_zero_or_none()
            )
        statement = statement.statement
    elif bind is None:
        bind = statement.bind 

    dialect = bind.dialect
    compiler = statement._compiler(dialect)
    class LiteralCompiler(compiler.__class__):
        def visit_bindparam(
                self, bindparam, within_columns_clause=False, 
                literal_binds=False, **kwargs
        ):
            return super(LiteralCompiler, self).render_literal_bindparam(
                    bindparam, within_columns_clause=within_columns_clause,
                    literal_binds=literal_binds, **kwargs
            )
        def render_literal_value(self, value, type_):
            """Render the value of a bind parameter as a quoted literal.

            This is used for statement sections that do not accept bind paramters
            on the target driver/database.

            This should be implemented by subclasses using the quoting services
            of the DBAPI.

            """
            if isinstance(value, basestring):
                value = value.replace("'", "''")
                return "'%s'" % value
            elif value is None:
                return "NULL"
            elif isinstance(value, (float, int, long)):
                return repr(value)
            elif isinstance(value, decimal.Decimal):
                return str(value)
            elif isinstance(value, datetime.datetime):
                return "TO_DATE('%s','YYYY-MM-DD HH24:MI:SS')" % value.strftime("%Y-%m-%d %H:%M:%S")

            else:
                raise NotImplementedError(
                            "Don't know how to literal-quote value %r" % value)            

    compiler = LiteralCompiler(dialect, statement)
    print compiler.process(statement)