Programs & Examples On #Wall time

Converting HTML to PDF using PHP?

If you wish to create a pdf from php, pdflib will help you (as some others suggested).

Else, if you want to convert an HTML page to PDF via PHP, you'll find a little trouble outta here.. For 3 years I've been trying to do it as best as I can.

So, the options I know are:

DOMPDF : php class that wraps the html and builds the pdf. Works good, customizable (if you know php), based on pdflib, if I remember right it takes even some CSS. Bad news: slow when the html is big or complex.

HTML2PS: same as DOMPDF, but this one converts first to a .ps (ghostscript) file, then, to whatever format you need (pdf, jpg, png). For me is little better than dompdf, but has the same speed problem.. but, better compatibility with CSS.

Those two are php classes, but if you can install some software on the server, and access it throught passthru() or system(), give a look to these too:

wkhtmltopdf: based on webkit (safari's wrapper), is really fast and powerful.. seems like this is the best one (atm) for converting html pages to pdf on the fly; taking only 2 seconds for a 3 page xHTML document with CSS2. It is a recent project, anyway, the google.code page is often updated.

htmldoc : This one is a tank, it never really stops/crashes.. the project looks dead since 2007, but anyway if you don't need CSS compatibility this can be nice for you.

Purpose of "%matplotlib inline"

Starting with IPython 5.0 and matplotlib 2.0 you can avoid the use of IPython’s specific magic and use matplotlib.pyplot.ion()/matplotlib.pyplot.ioff() which have the advantages of working outside of IPython as well.

ipython docs

How to convert enum value to int?

If you want the value you are assigning in the constructor, you need to add a method in the enum definition to return that value.

If you want a unique number that represent the enum value, you can use ordinal().

Read specific columns with pandas or other python module

Got a solution to above problem in a different way where in although i would read entire csv file, but would tweek the display part to show only the content which is desired.

import pandas as pd

df = pd.read_csv('data.csv', skipinitialspace=True)
print df[['star_name', 'ra']]

This one could help in some of the scenario's in learning basics and filtering data on the basis of columns in dataframe.

Python safe method to get value of nested dictionary

def safeget(_dct, *_keys):
    if not isinstance(_dct, dict): raise TypeError("Is not instance of dict")
    def foo(dct, *keys):
        if len(keys) == 0: return dct
        elif not isinstance(_dct, dict): return None
        else: return foo(dct.get(keys[0], None), *keys[1:])
    return foo(_dct, *_keys)

assert safeget(dict()) == dict()
assert safeget(dict(), "test") == None
assert safeget(dict([["a", 1],["b", 2]]),"a", "d") == None
assert safeget(dict([["a", 1],["b", 2]]),"a") == 1
assert safeget({"a":{"b":{"c": 2}},"d":1}, "a", "b")["c"] == 2

How to set the style -webkit-transform dynamically using JavaScript?

To animate your 3D object, use the code:

<script>

$(document).ready(function(){

    var x = 100;
    var y = 0;
setInterval(function(){
    x += 1;
    y += 1;
    var element = document.getElementById('cube');
    element.style.webkitTransform = "translateZ(-100px) rotateY("+x+"deg) rotateX("+y+"deg)"; //for safari and chrome
    element.style.MozTransform = "translateZ(-100px) rotateY("+x+"deg) rotateX("+y+"deg)"; //for firefox
},50);
//for other browsers use:   "msTransform",    "OTransform",    "transform"

});

</script>

Find everything between two XML tags with RegEx

It is not good to use this method but if you really want to split it with regex

<primaryAddress.*>((.|\n)*?)<\/primaryAddress>

the verified answer returns the tags but this just return the value between tags.

rake assets:precompile RAILS_ENV=production not working as required

Have you added this gem to your gemfile?

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

move that gem out of assets group and then run bundle again, I hope that would help!

SQL string value spanning multiple lines in query

I prefer to use the @ symbol so I see the query exactly as I can copy and paste into a query file:

string name = "Joe";
string gender = "M";
string query = String.Format(@"
SELECT
   *
FROM
   tableA
WHERE
   Name = '{0}' AND
   Gender = '{1}'", name, gender);

It's really great with long complex queries. Nice thing is it keeps tabs and line feeds so pasting into a query browser retains the nice formatting

Placing Unicode character in CSS content value

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

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

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

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

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


Relevant part of the CSS2 spec:

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

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

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

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

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

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

Count number of 1's in binary representation

The function takes an int and returns the number of Ones in binary representation

public static int findOnes(int number)
{

   if(number < 2)
    {
        if(number == 1)
        {
            count ++;
        }
        else
        {
            return 0;
        }
    }

    value = number % 2;

    if(number != 1 && value == 1)
        count ++;

    number /= 2;

    findOnes(number);

    return count;
}

Inserting values to SQLite table in Android

You'll find debugging errors like this a lot easier if you catch any errors thrown from the execSQL call. eg:

 try 
 {
      db.execSQL(Create_CashBook);  
 }
 catch (Exception e) 
 {
       Log.e("ERROR", e.toString());
 }

Reverting single file in SVN to a particular revision

I found it's simple to do this via the svn cat command so that you don't even have to specify a revision.

svn cat mydir/myfile > mydir/myfile

This probably won't role back the inode (metadata) data such as timestamps.

string comparison in batch file

While @ajv-jsy's answer works most of the time, I had the same problem as @MarioVilas. If one of the strings to be compared contains a double quote ("), the variable expansion throws an error.

Example:

@echo off
SetLocal

set Lhs="
set Rhs="

if "%Lhs%" == "%Rhs%" echo Equal

Error:

echo was unexpected at this time.

Solution:

Enable delayed expansion and use ! instead of %.

@echo off
SetLocal EnableDelayedExpansion

set Lhs="
set Rhs="

if !Lhs! == !Rhs! echo Equal

:: Surrounding with double quotes also works but appears (is?) unnecessary.
if "!Lhs!" == "!Rhs!" echo Equal

I have not been able to break it so far using this technique. It works with empty strings and all the symbols I threw at it.

Test:

@echo off
SetLocal EnableDelayedExpansion

:: Test empty string
set Lhs=
set Rhs=
echo Lhs: !Lhs! & echo Rhs: !Rhs!
if !Lhs! == !Rhs! (echo Equal) else (echo Not Equal)
echo.

:: Test symbols
set Lhs= \ / : * ? " ' < > | %% ^^ ` ~ @ # $ [ ] & ( ) + - _ =
set Rhs= \ / : * ? " ' < > | %% ^^ ` ~ @ # $ [ ] & ( ) + - _ =
echo Lhs: !Lhs! & echo Rhs: !Rhs!
if !Lhs! == !Rhs! (echo Equal) else (echo Not Equal)
echo.

How to update npm

For Ubuntu 18.04

npm install latest-version

I hope its for you also

Returning JSON object from an ASP.NET page

no problem doing it with asp.... it's most natural to do so with MVC, but can be done with standard asp as well.

The MVC framework has all sorts of helper classes for JSON, if you can, I'd suggest sussing in some MVC-love, if not, you can probably easily just get the JSON helper classes used by MVC in and use them in the context of asp.net.

edit:

here's an example of how to return JSON data with MVC. This would be in your controller class. This is out of the box functionality with MVC--when you crate a new MVC project this stuff gets auto-created so it's nothing special. The only thing that I"m doing is returning an actionResult that is JSON. The JSON method I'm calling is a method on the Controller class. This is all very basic, default MVC stuff:

public ActionResult GetData()
{
    var data = new { Name="kevin", Age=40 };
    return Json(data, JsonRequestBehavior.AllowGet);
}

This return data could be called via JQuery as an ajax call thusly:

$.get("/Reader/GetData/", function(data) { someJavacriptMethodOnData(data); });

Get a particular cell value from HTML table using JavaScript

To get the text from this cell-

<table>
    <tr id="somerow">
        <td>some text</td>            
    </tr>
</table>

You can use this -

var Row = document.getElementById("somerow");
var Cells = Row.getElementsByTagName("td");
alert(Cells[0].innerText);

How to approach a "Got minus one from a read call" error when connecting to an Amazon RDS Oracle instance

in my case, I got the same exception because the user that I configured in the app did not existed in the DB, creating the user and granting needed permissions solved the problem.

How correctly produce JSON by RESTful web service?

@POST
@Path ("Employee")
@Consumes("application/json")
@Produces("application/json")
public JSONObject postEmployee(JSONObject jsonObject)throws Exception{
    return jsonObject;
}       

AngularJS Dropdown required validation

You need to add a name attribute to your dropdown list, then you need to add a required attribute, and then you can reference the error using myForm.[input name].$error.required:

HTML:

        <form name="myForm" ng-controller="Ctrl" ng-submit="save(myForm)" novalidate>
        <input type="text" name="txtServiceName" ng-model="ServiceName" required>
<span ng-show="myForm.txtServiceName.$error.required">Enter Service Name</span>
<br/>
          <select name="service_id" class="Sitedropdown" style="width: 220px;"          
                  ng-model="ServiceID" 
                  ng-options="service.ServiceID as service.ServiceName for service in services"
                  required> 
            <option value="">Select Service</option> 
          </select> 
          <span ng-show="myForm.service_id.$error.required">Select service</span>

        </form>

    Controller:

        function Ctrl($scope) {
          $scope.services = [
            {ServiceID: 1, ServiceName: 'Service1'},
            {ServiceID: 2, ServiceName: 'Service2'},
            {ServiceID: 3, ServiceName: 'Service3'}
          ];

    $scope.save = function(myForm) {
    console.log('Selected Value: '+ myForm.service_id.$modelValue);
    alert('Data Saved! without validate');
    };
        }

Here's a working plunker.

mySQL :: insert into table, data from another table?

INSERT INTO action_2_members (campaign_id, mobile, vote, vote_date)  
SELECT campaign_id, from_number, received_msg, date_received
  FROM `received_txts`
 WHERE `campaign_id` = '8'

automating telnet session using bash scripts

Here is how to use telnet in bash shell/expect

#!/usr/bin/expect
# just do a chmod 755 one the script
# ./YOUR_SCRIPT_NAME.sh $YOUHOST $PORT
# if you get "Escape character is '^]'" as the output it means got connected otherwise it has failed

set ip [lindex $argv 0]
set port [lindex $argv 1]

set timeout 5
spawn telnet $ip $port
expect "'^]'."

python dictionary sorting in descending order based on values

Dictionaries do not have any inherent order. Or, rather, their inherent order is "arbitrary but not random", so it doesn't do you any good.

In different terms, your d and your e would be exactly equivalent dictionaries.

What you can do here is to use an OrderedDict:

from collections import OrderedDict
d = { '123': { 'key1': 3, 'key2': 11, 'key3': 3 },
      '124': { 'key1': 6, 'key2': 56, 'key3': 6 },
      '125': { 'key1': 7, 'key2': 44, 'key3': 9 },
    }
d_ascending = OrderedDict(sorted(d.items(), key=lambda kv: kv[1]['key3']))
d_descending = OrderedDict(sorted(d.items(), 
                                  key=lambda kv: kv[1]['key3'], reverse=True))

The original d has some arbitrary order. d_ascending has the order you thought you had in your original d, but didn't. And d_descending has the order you want for your e.


If you don't really need to use e as a dictionary, but you just want to be able to iterate over the elements of d in a particular order, you can simplify this:

for key, value in sorted(d.items(), key=lambda kv: kv[1]['key3'], reverse=True):
    do_something_with(key, value)

If you want to maintain a dictionary in sorted order across any changes, instead of an OrderedDict, you want some kind of sorted dictionary. There are a number of options available that you can find on PyPI, some implemented on top of trees, others on top of an OrderedDict that re-sorts itself as necessary, etc.

React: Expected an assignment or function call and instead saw an expression

Not sure about solutions but a temporary workaround is to ask eslint to ignore it by adding the following on top of the problem line.

// eslint-disable-next-line @typescript-eslint/no-unused-expressions

Extract value of attribute node via XPath

@ryenus, You need to loop through the result. This is how I'd do it in vbscript;

Set xmlDoc = CreateObject("Msxml2.DOMDocument")
xmlDoc.setProperty "SelectionLanguage", "XPath"
xmlDoc.load("kids.xml")

'Remove the id=1 attribute on Parent to return all child names for all Parent nodes
For Each c In xmlDoc.selectNodes ("//Parent[@id='1']/Children/child/@name")
    Wscript.Echo c.text
Next

How to check if a Unix .tar.gz file is a valid file without uncompressing?

A nice option is to use tar -tvvf <filePath> which adds a line that reports the kind of file.

Example in a valid .tar file:

> tar -tvvf filename.tar 
drwxr-xr-x  0 diegoreymendez staff       0 Jul 31 12:46 ./testfolder2/
-rw-r--r--  0 diegoreymendez staff      82 Jul 31 12:46 ./testfolder2/._.DS_Store
-rw-r--r--  0 diegoreymendez staff    6148 Jul 31 12:46 ./testfolder2/.DS_Store
drwxr-xr-x  0 diegoreymendez staff       0 Jul 31 12:42 ./testfolder2/testfolder/
-rw-r--r--  0 diegoreymendez staff      82 Jul 31 12:42 ./testfolder2/testfolder/._.DS_Store
-rw-r--r--  0 diegoreymendez staff    6148 Jul 31 12:42 ./testfolder2/testfolder/.DS_Store
-rw-r--r--  0 diegoreymendez staff  325377 Jul  5 09:50 ./testfolder2/testfolder/Scala.pages
Archive Format: POSIX ustar format,  Compression: none

Corrupted .tar file:

> tar -tvvf corrupted.tar 
tar: Unrecognized archive format
Archive Format: (null),  Compression: none
tar: Error exit delayed from previous errors.

Why is it common to put CSRF prevention tokens in cookies?

A good reason, which you have sort of touched on, is that once the CSRF cookie has been received, it is then available for use throughout the application in client script for use in both regular forms and AJAX POSTs. This will make sense in a JavaScript heavy application such as one employed by AngularJS (using AngularJS doesn't require that the application will be a single page app, so it would be useful where state needs to flow between different page requests where the CSRF value cannot normally persist in the browser).

Consider the following scenarios and processes in a typical application for some pros and cons of each approach you describe. These are based on the Synchronizer Token Pattern.

Request Body Approach

  1. User successfully logs in.
  2. Server issues auth cookie.
  3. User clicks to navigate to a form.
  4. If not yet generated for this session, server generates CSRF token, stores it against the user session and outputs it to a hidden field.
  5. User submits form.
  6. Server checks hidden field matches session stored token.

Advantages:

  • Simple to implement.
  • Works with AJAX.
  • Works with forms.
  • Cookie can actually be HTTP Only.

Disadvantages:

  • All forms must output the hidden field in HTML.
  • Any AJAX POSTs must also include the value.
  • The page must know in advance that it requires the CSRF token so it can include it in the page content so all pages must contain the token value somewhere, which could make it time consuming to implement for a large site.

Custom HTTP Header (downstream)

  1. User successfully logs in.
  2. Server issues auth cookie.
  3. User clicks to navigate to a form.
  4. Page loads in browser, then an AJAX request is made to retrieve the CSRF token.
  5. Server generates CSRF token (if not already generated for session), stores it against the user session and outputs it to a header.
  6. User submits form (token is sent via hidden field).
  7. Server checks hidden field matches session stored token.

Advantages:

Disadvantages:

  • Doesn't work without an AJAX request to get the header value.
  • All forms must have the value added to its HTML dynamically.
  • Any AJAX POSTs must also include the value.
  • The page must make an AJAX request first to get the CSRF token, so it will mean an extra round trip each time.
  • Might as well have simply output the token to the page which would save the extra request.

Custom HTTP Header (upstream)

  1. User successfully logs in.
  2. Server issues auth cookie.
  3. User clicks to navigate to a form.
  4. If not yet generated for this session, server generates CSRF token, stores it against the user session and outputs it in the page content somewhere.
  5. User submits form via AJAX (token is sent via header).
  6. Server checks custom header matches session stored token.

Advantages:

Disadvantages:

  • Doesn't work with forms.
  • All AJAX POSTs must include the header.

Custom HTTP Header (upstream & downstream)

  1. User successfully logs in.
  2. Server issues auth cookie.
  3. User clicks to navigate to a form.
  4. Page loads in browser, then an AJAX request is made to retrieve the CSRF token.
  5. Server generates CSRF token (if not already generated for session), stores it against the user session and outputs it to a header.
  6. User submits form via AJAX (token is sent via header) .
  7. Server checks custom header matches session stored token.

Advantages:

Disadvantages:

  • Doesn't work with forms.
  • All AJAX POSTs must also include the value.
  • The page must make an AJAX request first to get the CRSF token, so it will mean an extra round trip each time.

Set-Cookie

  1. User successfully logs in.
  2. Server issues auth cookie.
  3. User clicks to navigate to a form.
  4. Server generates CSRF token, stores it against the user session and outputs it to a cookie.
  5. User submits form via AJAX or via HTML form.
  6. Server checks custom header (or hidden form field) matches session stored token.
  7. Cookie is available in browser for use in additional AJAX and form requests without additional requests to server to retrieve the CSRF token.

Advantages:

  • Simple to implement.
  • Works with AJAX.
  • Works with forms.
  • Doesn't necessarily require an AJAX request to get the cookie value. Any HTTP request can retrieve it and it can be appended to all forms/AJAX requests via JavaScript.
  • Once the CSRF token has been retrieved, as it is stored in a cookie the value can be reused without additional requests.

Disadvantages:

  • All forms must have the value added to its HTML dynamically.
  • Any AJAX POSTs must also include the value.
  • The cookie will be submitted for every request (i.e. all GETs for images, CSS, JS, etc, that are not involved in the CSRF process) increasing request size.
  • Cookie cannot be HTTP Only.

So the cookie approach is fairly dynamic offering an easy way to retrieve the cookie value (any HTTP request) and to use it (JS can add the value to any form automatically and it can be employed in AJAX requests either as a header or as a form value). Once the CSRF token has been received for the session, there is no need to regenerate it as an attacker employing a CSRF exploit has no method of retrieving this token. If a malicious user tries to read the user's CSRF token in any of the above methods then this will be prevented by the Same Origin Policy. If a malicious user tries to retrieve the CSRF token server side (e.g. via curl) then this token will not be associated to the same user account as the victim's auth session cookie will be missing from the request (it would be the attacker's - therefore it won't be associated server side with the victim's session).

As well as the Synchronizer Token Pattern there is also the Double Submit Cookie CSRF prevention method, which of course uses cookies to store a type of CSRF token. This is easier to implement as it does not require any server side state for the CSRF token. The CSRF token in fact could be the standard authentication cookie when using this method, and this value is submitted via cookies as usual with the request, but the value is also repeated in either a hidden field or header, of which an attacker cannot replicate as they cannot read the value in the first place. It would be recommended to choose another cookie however, other than the authentication cookie so that the authentication cookie can be secured by being marked HttpOnly. So this is another common reason why you'd find CSRF prevention using a cookie based method.

Sequel Pro Alternative for Windows

You say you've had problems with Navicat. For the record, I use Navicat and I haven't experienced the issue you describe. You might want to dig around, see if there's a reason for your problem and/or a solution, because given the question asked, my first recommendation would have been Navicat.

But if you want alternative suggestions, here are a few that I know of and have used:

MySQL has its own tool which you can download for free, called MySQL Workbench. Download it from here: http://wb.mysql.com/. My experience is that it's powerful, but I didn't really like the UI. But that's just my personal taste.

Another free program you might want to try is HeidiSQL. It's more similar to Navicat than MySQL Workbench. A colleague of mine loves it.

(interesting to note, by the way, that MariaDB (the forked version of MySQL) is currently shipped with HeidiSQL as its GUI tool)

Finally, if you're running a web server on your machine, there's always the option of a browser-based tool like PHPMyAdmin. It's actually a surprisingly powerful piece of software.

unable to install pg gem

$ PATH=$PATH:/Library/PostgreSQL/9.1/bin sudo gem install pg

replace the 9.1 for the version installed on your system.

How to change TextBox's Background color?

If it's WPF, there is a collection of colors in the static class Brushes.

TextBox.Background = Brushes.Red;

Of course, you can create your own brush if you want.

LinearGradientBrush myBrush = new LinearGradientBrush();
myBrush.GradientStops.Add(new GradientStop(Colors.Yellow, 0.0));
myBrush.GradientStops.Add(new GradientStop(Colors.Orange, 0.5));
myBrush.GradientStops.Add(new GradientStop(Colors.Red, 1.0));
TextBox.Background = myBrush;

Why use pip over easy_install?

pip won't install binary packages and isn't well tested on Windows.

As Windows doesn't come with a compiler by default pip often can't be used there. easy_install can install binary packages for Windows.

How to pass an ArrayList to a varargs method parameter?

A shorter version of the accepted answer using Guava:

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

can be shortened further by statically importing toArray:

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

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

XmlWriter to Write to a String Instead of to a File

As Richard said, StringWriter is the way forward. There's one snag, however: by default, StringWriter will advertise itself as being in UTF-16. Usually XML is in UTF-8. You can fix this by subclassing StringWriter;

public class Utf8StringWriter : StringWriter
{
    public override Encoding Encoding
    {
         get { return Encoding.UTF8; }
    }
}

This will affect the declaration written by XmlWriter. Of course, if you then write the string out elsewhere in binary form, make sure you use an encoding which matches whichever encoding you fix for the StringWriter. (The above code always assumes UTF-8; it's trivial to make a more general version which accepts an encoding in the constructor.)

You'd then use:

using (TextWriter writer = new Utf8StringWriter())
{
    using (XmlWriter xmlWriter = XmlWriter.Create(writer))
    {
        ...
    }
    return writer.ToString();
}

How can I perform a short delay in C# without using sleep?

Sorry for awakening an old question like this. But I think what the original author wanted as an answer was:

You need to force your program to make the graphic update after you make the change to the textbox1. You can do that by invoking Update();

textBox1.Text += "\r\nThread Sleeps!";
textBox1.Update();
System.Threading.Thread.Sleep(4000);
textBox1.Text += "\r\nThread awakens!";
textBox1.Update();

Normally this will be done automatically when the thread is done. Ex, you press a button, changes are made to the text, thread dies, and then .Update() is fired and you see the changes. (I'm not an expert so I cant really tell you when its fired, but its something similar to this any way.)

In this case, you make a change, pause the thread, and then change the text again, and when the thread finally dies the .Update() is fired. This resulting in you only seeing the last change made to the text.

You would experience the same issue if you had a long execution between the text changes.

Pandas - How to flatten a hierarchical index in columns

The easiest and most intuitive solution for me was to combine the column names using get_level_values. This prevents duplicate column names when you do more than one aggregation on the same column:

level_one = df.columns.get_level_values(0).astype(str)
level_two = df.columns.get_level_values(1).astype(str)
df.columns = level_one + level_two

If you want a separator between columns, you can do this. This will return the same thing as Seiji Armstrong's comment on the accepted answer that only includes underscores for columns with values in both index levels:

level_one = df.columns.get_level_values(0).astype(str)
level_two = df.columns.get_level_values(1).astype(str)
column_separator = ['_' if x != '' else '' for x in level_two]
df.columns = level_one + column_separator + level_two

I know this does the same thing as Andy Hayden's great answer above, but I think it is a bit more intuitive this way and is easier to remember (so I don't have to keep referring to this thread), especially for novice pandas users.

This method is also more extensible in the case where you may have 3 column levels.

level_one = df.columns.get_level_values(0).astype(str)
level_two = df.columns.get_level_values(1).astype(str)
level_three = df.columns.get_level_values(2).astype(str)
df.columns = level_one + level_two + level_three

svn list of files that are modified in local copy

Using Powershell you can do this:

# Checks for updates and changes in working copy.
# Regex: Excludes unmodified (first 7 columns blank). To exclude more add criteria to negative look ahead.
# -u: svn gets updates
$regex = '^(?!\s{7}).{7}\s+(.+)';
svn status -u | %{ if($_ -match $regex){ $_ } };

This will include property changes. These show in column 2. It will also catch other differences in files that show in columns 3-7.

Sources:

/usr/bin/codesign failed with exit code 1

When I got this error I wasn't even trying to sign the app. I was writing a test app and didn't care about signing. In order to get rid of this message I had to select "Don't Code Sign" from Build Settings under Code Signing.

enter image description here

How can I set a website image that will show as preview on Facebook?

If you're using Weebly, start by viewing the published site and right-clicking the image to Copy Image Address. Then in Weebly, go to Edit Site, Pages, click the page you wish to use, SEO Settings, under Header Code enter the code from Shef's answer:

<meta property="og:image" content="/uploads/..." />

just replacing /uploads/... with the copied image address. Click Publish to apply the change.

You can skip the part of Shef's answer about namespace, because that's already set by default in Weebly.

Converting datetime.date to UTC timestamp in Python

Using the arrow package:

>>> import arrow
>>> arrow.get(2010, 12, 31).timestamp
1293753600
>>> time.gmtime(1293753600)
time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31, 
    tm_hour=0, tm_min=0, tm_sec=0, 
    tm_wday=4, tm_yday=365, tm_isdst=0)

How to target only IE (any version) within a stylesheet?

Internet Explorer 9 and lower : You could use conditional comments to load an IE-specific stylesheet for any version (or combination of versions) that you wanted to specifically target.like below using external stylesheet.

<!--[if IE]>
  <link rel="stylesheet" type="text/css" href="all-ie-only.css" />
<![endif]-->

However, beginning in version 10, conditional comments are no longer supported in IE.

Internet Explorer 10 & 11 : Create a media query using -ms-high-contrast, in which you place your IE 10 and 11-specific CSS styles. Because -ms-high-contrast is Microsoft-specific (and only available in IE 10+), it will only be parsed in Internet Explorer 10 and greater.

@media all and (-ms-high-contrast: none), (-ms-high-contrast: active) {
     /* IE10+ CSS styles go here */
}

Microsoft Edge 12 : Can use the @supports rule Here is a link with all the info about this rule

@supports (-ms-accelerator:true) {
  /* IE Edge 12+ CSS styles go here */ 
}

Inline rule IE8 detection

I have 1 more option but it is only detect IE8 and below version.

  /* For IE css hack */
  margin-top: 10px\9 /* apply to all ie from 8 and below */
  *margin-top:10px;  /* apply to ie 7 and below */
  _margin-top:10px; /* apply to ie 6 and below */

As you specefied for embeded stylesheet. I think you need to use media query and condition comment for below version.

How do I delete specific lines in Notepad++?

Jacob's reply to John T works perfectly to delete the whole line, and you can Find in Files with that. Make sure to check "Regular expression" at bottom.

Solution: ^.*#region.*$

Update and left outer join statements

If what you need is UPDATE from SELECT statement you can do something like this:

UPDATE suppliers    
SET city = (SELECT customers.city FROM customers

WHERE customers.customer_name = suppliers.supplier_name)

PHP regular expression - filter number only

Another way to get only the numbers in a regex string is as shown below:

$output = preg_replace("/\D+/", "", $input);

ASP.NET: HTTP Error 500.19 – Internal Server Error 0x8007000d

For me, it was all about setting up my web server to use the latest-and-greatest tech to support my ASP.NET 5 application!

The following URL gave me all the tips I needed:

https://docs.asp.net/en/1.0.0-rc1/publishing/iis-with-msdeploy.html

Hope this helps :)

JPA or JDBC, how are they different?

JDBC is the predecessor of JPA.

JDBC is a bridge between the Java world and the databases world. In JDBC you need to expose all dirty details needed for CRUD operations, such as table names, column names, while in JPA (which is using JDBC underneath), you also specify those details of database metadata, but with the use of Java annotations.

So JPA creates update queries for you and manages the entities that you looked up or created/updated (it does more as well).

If you want to do JPA without a Java EE container, then Spring and its libraries may be used with the very same Java annotations.

How to comment and uncomment blocks of code in the Office VBA Editor

Or just click View, ToolBars, Edit. Then you can select a block of code and then click the Comment or Uncomment toolbar button to do everything in one click.

As an aside, you can Tab/Shift+Tab a block of selected text also. When I was a noobie, I didn't know that for a long time and would do them one line at a time.

Good Luck!

Task vs Thread differences

Usually you hear Task is a higher level concept than thread... and that's what this phrase means:

  1. You can't use Abort/ThreadAbortedException, you should support cancel event in your "business code" periodically testing token.IsCancellationRequested flag (also avoid long or timeoutless connections e.g. to db, otherwise you will never get a chance to test this flag). By the similar reason Thread.Sleep(delay) call should be replaced with Task.Delay(delay, token) call (passing token inside to have possibility to interrupt delay).

  2. There are no thread's Suspend and Resume methods functionality with tasks. Instance of task can't be reused either.

  3. But you get two new tools:

    a) continuations

    // continuation with ContinueWhenAll - execute the delegate, when ALL
    // tasks[] had been finished; other option is ContinueWhenAny
    
    Task.Factory.ContinueWhenAll( 
       tasks,
       () => {
           int answer = tasks[0].Result + tasks[1].Result;
           Console.WriteLine("The answer is {0}", answer);
       }
    );
    

    b) nested/child tasks

    //StartNew - starts task immediately, parent ends whith child
    var parent = Task.Factory.StartNew
    (() => {
              var child = Task.Factory.StartNew(() =>
             {
             //...
             });
          },  
          TaskCreationOptions.AttachedToParent
    );
    
  4. So system thread is completely hidden from task, but still task's code is executed in the concrete system thread. System threads are resources for tasks and ofcourse there is still thread pool under the hood of task's parallel execution. There can be different strategies how thread get new tasks to execute. Another shared resource TaskScheduler cares about it. Some problems that TaskScheduler solves 1) prefer to execute task and its conitnuation in the same thread minimizing switching cost - aka inline execution) 2) prefer execute tasks in an order they were started - aka PreferFairness 3) more effective distribution of tasks between inactive threads depending on "prior knowledge of tasks activity" - aka Work Stealing. Important: in general "async" is not same as "parallel". Playing with TaskScheduler options you can setup async tasks be executed in one thread synchronously. To express parallel code execution higher abstractions (than Tasks) could be used: Parallel.ForEach, PLINQ, Dataflow.

  5. Tasks are integrated with C# async/await features aka Promise Model, e.g there requestButton.Clicked += async (o, e) => ProcessResponce(await client.RequestAsync(e.ResourceName)); the execution of client.RequestAsync will not block UI thread. Important: under the hood Clicked delegate call is absolutely regular (all threading is done by compiler).

That is enough to make a choice. If you need to support Cancel functionality of calling legacy API that tends to hang (e.g. timeoutless connection) and for this case supports Thread.Abort(), or if you are creating multithread background calculations and want to optimize switching between threads using Suspend/Resume, that means to manage parallel execution manually - stay with Thread. Otherwise go to Tasks because of they will give you easy manipulate on groups of them, are integrated into the language and make developers more productive - Task Parallel Library (TPL) .

Can an AWS Lambda function call another

Here is the python example of calling another lambda function and gets its response. There is two invocation type 'RequestResponse' and 'Event'. Use 'RequestResponse' if you want to get the response of lambda function and use 'Event' to invoke lambda function asynchronously. So both ways asynchronous and synchronous are available.

    lambda_response = lambda_client.invoke(
                FunctionName = lambda_name,
                InvocationType = 'RequestResponse',
                Payload = json.dumps(input)
                )
    resp_str = lambda_response['Payload'].read()
    response = json.loads(resp_str)

Find Active Tab using jQuery and Twitter Bootstrap

Here is the answer for those of you who need a Boostrap 3 solution.

In bootstrap 3 use 'shown.bs.tab' instead of 'shown' in the next line

// tab
$('#rowTab a:first').tab('show');

$('a[data-toggle="tab"]').on('shown.bs.tab', function (e) {
//show selected tab / active
 console.log ( $(e.target).attr('id') );
});

What is special about /dev/tty?

/dev/tty is a synonym for the controlling terminal (if any) of the current process. As jtl999 says, it's a character special file; that's what the c in the ls -l output means.

man 4 tty or man -s 4 tty should give you more information, or you can read the man page online here.

Incidentally, pwd > /dev/tty doesn't necessarily print to the shell's stdout (though it is the pwd command's standard output). If the shell's standard output has been redirected to something other than the terminal, /dev/tty still refers to the terminal.

You can also read from /dev/tty, which will normally read from the keyboard.

What's the UIScrollView contentInset property for?

While jball's answer is an excellent description of content insets, it doesn't answer the question of when to use it. I'll borrow from his diagrams:

  _|?_cW_?_|_?_
   |       | 
---------------
   |content| ?
 ? |content| contentInset.top
cH |content|
 ? |content| contentInset.bottom
   |content| ?
---------------
   |content|    
-------------?-

That's what you get when you do it, but the usefulness of it only shows when you scroll:

  _|?_cW_?_|_?_
   |content| ? content is still visible
---------------
   |content| ?
 ? |content| contentInset.top
cH |content|
 ? |content| contentInset.bottom
   |content| ?
---------------
  _|_______|___ 
             ?

That top row of content will still be visible because it's still inside the frame of the scroll view. One way to think of the top offset is "how much to shift the content down the scroll view when we're scrolled all the way to the top"

To see a place where this is actually used, look at the build-in Photos app on the iphone. The Navigation bar and status bar are transparent, and the contents of the scroll view are visible underneath. That's because the scroll view's frame extends out that far. But if it wasn't for the content inset, you would never be able to have the top of the content clear that transparent navigation bar when you go all the way to the top.

asp:TextBox ReadOnly=true or Enabled=false?

Readonly will not "grayout" the textbox and will still submit the value on a postback.

cannot import name patterns

As of Django 1.10, the patterns module has been removed (it had been deprecated since 1.8).

Luckily, it should be a simple edit to remove the offending code, since the urlpatterns should now be stored in a plain-old list:

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    # ... your url patterns
]

Hide the browse button on a input type=file

Below code is very useful to hide default browse button and use custom instead:

_x000D_
_x000D_
(function($) {_x000D_
  $('input[type="file"]').bind('change', function() {_x000D_
    $("#img_text").html($('input[type="file"]').val());_x000D_
  });_x000D_
})(jQuery)
_x000D_
.file-input-wrapper {_x000D_
  height: 30px;_x000D_
  margin: 2px;_x000D_
  overflow: hidden;_x000D_
  position: relative;_x000D_
  width: 118px;_x000D_
  background-color: #fff;_x000D_
  cursor: pointer;_x000D_
}_x000D_
_x000D_
.file-input-wrapper>input[type="file"] {_x000D_
  font-size: 40px;_x000D_
  position: absolute;_x000D_
  top: 0;_x000D_
  right: 0;_x000D_
  opacity: 0;_x000D_
  cursor: pointer;_x000D_
}_x000D_
_x000D_
.file-input-wrapper>.btn-file-input {_x000D_
  background-color: #494949;_x000D_
  border-radius: 4px;_x000D_
  color: #fff;_x000D_
  display: inline-block;_x000D_
  height: 34px;_x000D_
  margin: 0 0 0 -1px;_x000D_
  padding-left: 0;_x000D_
  width: 121px;_x000D_
  cursor: pointer;_x000D_
}_x000D_
_x000D_
.file-input-wrapper:hover>.btn-file-input {_x000D_
  //background-color: #494949;_x000D_
}_x000D_
_x000D_
#img_text {_x000D_
  float: right;_x000D_
  margin-right: -80px;_x000D_
  margin-top: -14px;_x000D_
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<body>_x000D_
  <div class="file-input-wrapper">_x000D_
    <button class="btn-file-input">SELECT FILES</button>_x000D_
    <input type="file" name="image" id="image" value="" />_x000D_
  </div>_x000D_
  <span id="img_text"></span>_x000D_
</body>
_x000D_
_x000D_
_x000D_

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 32 bytes)

Well try ini_set('memory_limit', '256M');

134217728 bytes = 128 MB

Or rewrite the code to consume less memory.

jQuery posting valid json in request body

An actual JSON request would look like this:

data: '{"command":"on"}',

Where you're sending an actual JSON string. For a more general solution, use JSON.stringify() to serialize an object to JSON, like this:

data: JSON.stringify({ "command": "on" }),

To support older browsers that don't have the JSON object, use json2.js which will add it in.


What's currently happening is since you have processData: false, it's basically sending this: ({"command":"on"}).toString() which is [object Object]...what you see in your request.

Automatically start a Windows Service on install

You corrupted your designer. ReAdd your Installer Component. It should have a serviceInstaller and a serviceProcessInstaller. The serviceInstaller with property Startup Method set to Automatic will startup when installed and after each reboot.

phantomjs not waiting for "full" page load

In my program, I use some logic to judge if it was onload: watching it's network request, if there was no new request on past 200ms, I treat it onload.

Use this, after onLoadFinish().

function onLoadComplete(page, callback){
    var waiting = [];  // request id
    var interval = 200;  //ms time waiting new request
    var timer = setTimeout( timeout, interval);
    var max_retry = 3;  //
    var counter_retry = 0;

    function timeout(){
        if(waiting.length && counter_retry < max_retry){
            timer = setTimeout( timeout, interval);
            counter_retry++;
            return;
        }else{
            try{
                callback(null, page);
            }catch(e){}
        }
    }

    //for debug, log time cost
    var tlogger = {};

    bindEvent(page, 'request', function(req){
        waiting.push(req.id);
    });

    bindEvent(page, 'receive', function (res) {
        var cT = res.contentType;
        if(!cT){
            console.log('[contentType] ', cT, ' [url] ', res.url);
        }
        if(!cT) return remove(res.id);
        if(cT.indexOf('application') * cT.indexOf('text') != 0) return remove(res.id);

        if (res.stage === 'start') {
            console.log('!!received start: ', res.id);
            //console.log( JSON.stringify(res) );
            tlogger[res.id] = new Date();
        }else if (res.stage === 'end') {
            console.log('!!received end: ', res.id, (new Date() - tlogger[res.id]) );
            //console.log( JSON.stringify(res) );
            remove(res.id);

            clearTimeout(timer);
            timer = setTimeout(timeout, interval);
        }

    });

    bindEvent(page, 'error', function(err){
        remove(err.id);
        if(waiting.length === 0){
            counter_retry = 0;
        }
    });

    function remove(id){
        var i = waiting.indexOf( id );
        if(i < 0){
            return;
        }else{
            waiting.splice(i,1);
        }
    }

    function bindEvent(page, evt, cb){
        switch(evt){
            case 'request':
                page.onResourceRequested = cb;
                break;
            case 'receive':
                page.onResourceReceived = cb;
                break;
            case 'error':
                page.onResourceError = cb;
                break;
            case 'timeout':
                page.onResourceTimeout = cb;
                break;
        }
    }
}

Resizing image in Java

Resize image with high quality:

private static InputStream resizeImage(InputStream uploadedInputStream, String fileName, int width, int height) {

        try {
            BufferedImage image = ImageIO.read(uploadedInputStream);
            Image originalImage= image.getScaledInstance(width, height, Image.SCALE_DEFAULT);

            int type = ((image.getType() == 0) ? BufferedImage.TYPE_INT_ARGB : image.getType());
            BufferedImage resizedImage = new BufferedImage(width, height, type);

            Graphics2D g2d = resizedImage.createGraphics();
            g2d.drawImage(originalImage, 0, 0, width, height, null);
            g2d.dispose();
            g2d.setComposite(AlphaComposite.Src);
            g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g2d.setRenderingHint(RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);

            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

            ImageIO.write(resizedImage, fileName.split("\\.")[1], byteArrayOutputStream);
            return new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
        } catch (IOException e) {
            // Something is going wrong while resizing image
            return uploadedInputStream;
        }
    }

TNS-12505: TNS:listener does not currently know of SID given in connect descriptor

In my case i just went through following steps in windows 10.

  1. goto control panel
  2. click administrative
  3. click services
  4. find OracelServeceXE, OracleXEClrAgeng, OracleXETNSListener
  5. Right click and press Start/Restart
  6. After Completing Process. Check it will work or it will work ;)
  7. Done
  8. All the Best.

The differences between initialize, define, declare a variable

For C, at least, per C11 6.7.5:

A declaration specifies the interpretation and attributes of a set of identifiers. A definition of an identifier is a declaration for that identifier that:

  • for an object, causes storage to be reserved for that object;

  • for a function, includes the function body;

  • for an enumeration constant, is the (only) declaration of the identifier;

  • for a typedef name, is the first (or only) declaration of the identifier.

Per C11 6.7.9.8-10:

An initializer specifies the initial value stored in an object ... if an object that has automatic storage is not initialized explicitly, its value is indeterminate.

So, broadly speaking, a declaration introduces an identifier and provides information about it. For a variable, a definition is a declaration which allocates storage for that variable.

Initialization is the specification of the initial value to be stored in an object, which is not necessarily the same as the first time you explicitly assign a value to it. A variable has a value when you define it, whether or not you explicitly give it a value. If you don't explicitly give it a value, and the variable has automatic storage, it will have an initial value, but that value will be indeterminate. If it has static storage, it will be initialized implicitly depending on the type (e.g. pointer types get initialized to null pointers, arithmetic types get initialized to zero, and so on).

So, if you define an automatic variable without specifying an initial value for it, such as:

int myfunc(void) {
    int myvar;
    ...

You are defining it (and therefore also declaring it, since definitions are declarations), but not initializing it. Therefore, definition does not equal declaration plus initialization.

Android 5.0 - Add header/footer to a RecyclerView

I know I come late, but only recently I was able to implement such "addHeader" to the Adapter. In my FlexibleAdapter project you can call setHeader on a Sectionable item, then you call showAllHeaders. If you need only 1 header then the first item should have the header. If you delete this item, then the header is automatically linked to the next one.

Unfortunately footers are not covered (yet).

The FlexibleAdapter allows you to do much more than create headers/sections. You really should have a look: https://github.com/davideas/FlexibleAdapter.

How to disable mouse right click on a web page?

Please do not do that, it is very annoying.

The right menu is there for a reason, and it should be left there. Many browser extensions add entries to the right click menu and the user should be able to use it in any page he visits.

Moreover you can use all of the functionality of the right click menu in other ways (keyboard shortcuts, browser menu etc etc etc) so blocking the right click menu has the only effect of annoying the user.

PS: If really you cannot resist the urge to block it at least do not put a popup saying "no right click allowed".

Error converting data types when importing from Excel to SQL Server 2008

There seems to be a really easy solution when dealing with data type issues.

Basically, at the end of Excel connection string, add ;IMEX=1;"

Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\\YOURSERVER\shared\Client Projects\FOLDER\Data\FILE.xls;Extended Properties="EXCEL 8.0;HDR=YES;IMEX=1";

This will resolve data type issues such as columns where values are mixed with text and numbers.

To get to connection property, right click on Excel connection manager below control flow and hit properties. It'll be to the right under solution explorer. Hope that helps.

Simple VBA selection: Selecting 5 cells to the right of the active cell

This example selects a new Range of Cells defined by the current cell to a cell 5 to the right.

Note that .Offset takes arguments of Offset(row, columns) and can be quite useful.


Sub testForStackOverflow()
    Range(ActiveCell, ActiveCell.Offset(0, 5)).Copy
End Sub

Are there any free Xml Diff/Merge tools available?

Have a look at at File comparison tools, from which I am using WinMerge. It has an ability to compare XML documents (you may wish to enable DisplayXMLFiles prefilter).

DisplayXMLFiles.dll - This plugin pretty-prints XML files nicely by inserting tabs and line breaks. This is useful for XML files that do not have line returns in convenient locations.

WinMerge in action

See also my feature comparison table.

Declaring variables inside loops, good practice or bad practice?

This is excellent practice.

By creating variables inside loops, you ensure their scope is restricted to inside the loop. It cannot be referenced nor called outside of the loop.

This way:

  • If the name of the variable is a bit "generic" (like "i"), there is no risk to mix it with another variable of same name somewhere later in your code (can also be mitigated using the -Wshadow warning instruction on GCC)

  • The compiler knows that the variable scope is limited to inside the loop, and therefore will issue a proper error message if the variable is by mistake referenced elsewhere.

  • Last but not least, some dedicated optimization can be performed more efficiently by the compiler (most importantly register allocation), since it knows that the variable cannot be used outside of the loop. For example, no need to store the result for later re-use.

In short, you are right to do it.

Note however that the variable is not supposed to retain its value between each loop. In such case, you may need to initialize it every time. You can also create a larger block, encompassing the loop, whose sole purpose is to declare variables which must retain their value from one loop to another. This typically includes the loop counter itself.

{
    int i, retainValue;
    for (i=0; i<N; i++)
    {
       int tmpValue;
       /* tmpValue is uninitialized */
       /* retainValue still has its previous value from previous loop */

       /* Do some stuff here */
    }
    /* Here, retainValue is still valid; tmpValue no longer */
}

For question #2: The variable is allocated once, when the function is called. In fact, from an allocation perspective, it is (nearly) the same as declaring the variable at the beginning of the function. The only difference is the scope: the variable cannot be used outside of the loop. It may even be possible that the variable is not allocated, just re-using some free slot (from other variable whose scope has ended).

With restricted and more precise scope come more accurate optimizations. But more importantly, it makes your code safer, with less states (i.e. variables) to worry about when reading other parts of the code.

This is true even outside of an if(){...} block. Typically, instead of :

    int result;
    (...)
    result = f1();
    if (result) then { (...) }
    (...)
    result = f2();
    if (result) then { (...) }

it's safer to write :

    (...)
    {
        int const result = f1();
        if (result) then { (...) }
    }
    (...)
    {
        int const result = f2();
        if (result) then { (...) }
    }

The difference may seem minor, especially on such a small example. But on a larger code base, it will help : now there is no risk to transport some result value from f1() to f2() block. Each result is strictly limited to its own scope, making its role more accurate. From a reviewer perspective, it's much nicer, since he has less long range state variables to worry about and track.

Even the compiler will help better : assuming that, in the future, after some erroneous change of code, result is not properly initialized with f2(). The second version will simply refuse to work, stating a clear error message at compile time (way better than run time). The first version will not spot anything, the result of f1() will simply be tested a second time, being confused for the result of f2().

Complementary information

The open-source tool CppCheck (a static analysis tool for C/C++ code) provides some excellent hints regarding optimal scope of variables.

In response to comment on allocation: The above rule is true in C, but might not be for some C++ classes.

For standard types and structures, the size of variable is known at compilation time. There is no such thing as "construction" in C, so the space for the variable will simply be allocated into the stack (without any initialization), when the function is called. That's why there is a "zero" cost when declaring the variable inside a loop.

However, for C++ classes, there is this constructor thing which I know much less about. I guess allocation is probably not going to be the issue, since the compiler shall be clever enough to reuse the same space, but the initialization is likely to take place at each loop iteration.

How do I count unique items in field in Access query?

Access-Engine does not support

SELECT count(DISTINCT....) FROM ...

You have to do it like this:

SELECT count(*) 
FROM
(SELECT DISTINCT Name FROM table1)

Its a little workaround... you're counting a DISTINCT selection.

Printing pointers in C

"s" is not a "char*", it's a "char[4]". And so, "&s" is not a "char**", but actually "a pointer to an array of 4 characater". Your compiler may treat "&s" as if you had written "&s[0]", which is roughly the same thing, but is a "char*".

When you write "char** p = &s;" you are trying to say "I want p to be set to the address of the thing which currently points to "asd". But currently there is nothing which points to "asd". There is just an array which holds "asd";

char s[] = "asd";
char *p = &s[0];  // alternately you could use the shorthand char*p = s;
char **pp = &p;

Python and JSON - TypeError list indices must be integers not str

You can simplify your code down to

url = "http://worldcup.kimonolabs.com/api/players?apikey=xxx"
json_obj = urllib2.urlopen(url).read
player_json_list = json.loads(json_obj)
for player in readable_json_list:
    print player['firstName']

You were trying to access a list element using dictionary syntax. the equivalent of

foo = [1, 2, 3, 4]
foo["1"]

It can be confusing when you have lists of dictionaries and keeping the nesting in order.

INNER JOIN vs INNER JOIN (SELECT . FROM)

Seems to be identical just in case that SQL server will not try to read data which is not required for the query, the optimizer is clever enough

It can have sense when join on complex query (i.e which have joings, groupings etc itself) then, yes, it is better to specify required fields.

But there is one more point. If the query is simple there is no difference but EVERY extra action even which is supposed to improve performance makes optimizer works harder and optimizer can fail to get the best plan in time and will run not optimal query. So extras select can be a such action which can even decrease performance

What is the difference between .yaml and .yml extension?

As @David Heffeman indicates the recommendation is to use .yaml when possible, and the recommendation has been that way since September 2006.

That some projects use .yml is mostly because of ignorance of the implementers/documenters: they wanted to use YAML because of readability, or some other feature not available in other formats, were not familiar with the recommendation and and just implemented what worked, maybe after looking at some other project/library (without questioning whether what was done is correct).

The best way to approach this is to be rigorous when creating new files (i.e. use .yaml) and be permissive when accepting input (i.e. allow .yml when you encounter it), possible automatically upgrading/correcting these errors when possible.

The other recommendation I have is to document the argument(s) why you have to use .yml, when you think you have to. That way you don't look like an ignoramus, and give others the opportunity to understand your reasoning. Of course "everybody else is doing it" and "On Google .yml has more pages than .yaml" are not arguments, they are just statistics about the popularity of project(s) that have it wrong or right (with regards to the extension of YAML files). You can try to prove that some projects are popular, just because they use a .yml extension instead of the correct .yaml, but I think you will be hard pressed to do so.

Some projects realize (too late) that they use the incorrect extension (e.g. originally docker-compose used .yml, but in later versions started to use .yaml, although they still support .yml). Others still seem ignorant about the correct extension, like AppVeyor early 2019, but allow you to specify the configuration file for a project, including extension. This allows you to get the configuration file out of your face as well as giving it the proper extension: I use .appveyor.yaml instead of appveyor.yml for building the windows wheels of my YAML parser for Python).


On the other hand:

The Yaml (sic!) component of Symfony2 implements a selected subset of features defined in the YAML 1.2 version specification.

So it seems fitting that they also use a subset of the recommended extension.

Difference between AutoPostBack=True and AutoPostBack=False?

AutoPostBack = true permits control to post back to the server. It is associated with an Event.

Example:

<asp:DropDownList id="id" runat="server" AutoPostBack="true" OnSelectIndexChanged="..."/>

The aspx page with the above drop down list does not need an asp:button to do the post back. When you change an option in the drop down list, the page gets posted back to the server.

Default value of AutoPostBack on control is false.

How do I remove a file from the FileList

Since JavaScript FileList is readonly and cannot be manipulated directly,

BEST METHOD

You will have to loop through the input.files while comparing it with the index of the file you want to remove. At the same time, you will use new DataTransfer() to set a new list of files excluding the file you want to remove from the file list.

With this approach, the value of the input.files itself is changed.

removeFileFromFileList(index) {
  const dt = new DataTransfer()
  const input = document.getElementById('files')
  const { files } = input
  for (let i = 0; i < files.length; i++) {
    const file = files[i]
    if (index !== i) dt.items.add(file) // here you exclude the file. thus removing it.
    input.files = dt.files
  }
}

ALTERNATIVE METHOD

Another simple method is to convert the FileList into an array and then splice it.

But this approach will not change the input.files

const input = document.getElementById('files')
// as an array, u have more freedom to transform the file list using array functions.
const fileListArr = Array.from(input.files)
fileListArr.splice(index, 1) // here u remove the file
console.log(fileListArr)

Change remote repository credentials (authentication) on Intellij IDEA 14

This is how I solved it on Windows. I have git installed separately, and Idea just picks git's options automatically (Default Idea config, as I would get from clean installer).

Open the project in the command line. Make some changes there. And commit and push files via git which is installed on my machine. During push it will open a windows asking me to enter username and password. After that, when I make a commit-push from idea, it will simply work.

How to create and add users to a group in Jenkins for authentication?

I installed the Role plugin under Jenkins-3.5, but it does not show the "Manage Roles" option under "Manage Jenkins", and when one follows the security install page from the wiki, all users are locked out instantly. I had to manually shutdown Jenkins on the server, restore the correct configuration settings (/me is happy to do proper backups) and restart Jenkins.

I didn't have high hopes, as that plugin was last updated in 2011

Proper way to concatenate variable strings

Since strings are lists of characters in Python, we can concatenate strings the same way we concatenate lists (with the + sign):

{{ var1 + '-' + var2 + '-' + var3 }}

If you want to pipe the resulting string to some filter, make sure you enclose the bits in parentheses:

e.g. To concatenate our 3 vars, and get a sha512 hash:

{{ (var1 + var2 + var3) | hash('sha512') }}

Note: this works on Ansible 2.3. I haven't tested it on earlier versions.

There can be only one auto column

My MySQL says "Incorrect table definition; there can be only one auto column and it must be defined as a key" So when I added primary key as below it started working:

CREATE TABLE book (
   id INT AUTO_INCREMENT NOT NULL,
   accepted_terms BIT(1) NOT NULL,
   accepted_privacy BIT(1) NOT NULL,
   primary key (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

How to check if a value exists in a dictionary (python)

Use dictionary views:

if x in d.viewvalues():
    dosomething()..

Change default date time format on a single database in SQL Server

You do realize that format has nothing to do with how SQL Server stores datetime, right?

You can use set dateformat for each session. There is no setting for database only.

If you use parameters for data insert or update or where filtering you won't have any problems with that.

How to clone an InputStream?

You can't clone it, and how you are going to solve your problem depends on what the source of the data is.

One solution is to read all data from the InputStream into a byte array, and then create a ByteArrayInputStream around that byte array, and pass that input stream into your method.

Edit 1: That is, if the other method also needs to read the same data. I.e you want to "reset" the stream.

Why is synchronized block better than synchronized method?

Difference between synchronized block and synchronized method are following:

  1. synchronized block reduce scope of lock, but synchronized method's scope of lock is whole method.
  2. synchronized block has better performance as only the critical section is locked but synchronized method has poor performance than block.
  3. synchronized block provide granular control over lock but synchronized method lock either on current object represented by this or class level lock.
  4. synchronized block can throw NullPointerException but synchronized method doesn't throw.
  5. synchronized block: synchronized(this){}

    synchronized method: public synchronized void fun(){}

Simplest way to throw an error/exception with a custom message in Swift 2?

Throwing code should make clear whether the error message is appropriate for display to end users or is only intended for developer debugging. To indicate a description is displayable to the user, I use a struct DisplayableError that implements the LocalizedError protocol.

struct DisplayableError: Error, LocalizedError {
    let errorDescription: String?

    init(_ description: String) {
        errorDescription = description
    }
}

Usage for throwing:

throw DisplayableError("Out of pixie dust.")

Usage for display:

let messageToDisplay = error.localizedDescription

Add resources, config files to your jar using gradle

I ran into the same problem. I had a PNG file in a Java package and it wasn't exported in the final JAR along with the sources, which caused the app to crash upon start (file not found).

None of the answers above solved my problem but I found the solution on the Gradle forums. I added the following to my build.gradle file :

sourceSets.main.resources.srcDirs = [ "src/" ]
sourceSets.main.resources.includes = [ "**/*.png" ]

It tells Gradle to look for resources in the src folder, and ask it to include only PNG files.

EDIT: Beware that if you're using Eclipse, this will break your run configurations and you'll get a main class not found error when trying to run your program. To fix that, the only solution I've found is to move the image(s) to another directory, res/ for example, and to set it as srcDirs instead of src/.

Are the shift operators (<<, >>) arithmetic or logical in C?

According to many compilers:

  1. << is an arithmetic left shift or bitwise left shift.
  2. >> is an arithmetic right shiftor bitwise right shift.

Yahoo Finance All Currencies quote API Documentation

I'm developing an application that needs currency conversion, and been using Open Exchange Rates because I wouldn't be paying since the app is in testing. But as of September 2012 Open Exchange Rates is gonna be paid for non-personal, so I checked out that they were using the Yahoo Finance Webservice (the one that "doesn't exist") and looking for documentation on it got here, and opted to use YQL.

Using YQL with the Yahoo Finance table (yahoo.finance.quotes) linked by NT3RP, currencies appear with symbol="ISOCODE=X", for example: "ARS=X" for Argentine Peso, "AUD=X" for Australian Dollar. "USD=X" doesn't exist, but it would be 1, since the rest are rates against USD.

The "price" value on the OP API is in the field "LastTradePriceOnly" of the table. For my application I used the "Ask" field.

How do I manually create a file with a . (dot) prefix in Windows? For example, .htaccess

Might sound unbelivable, but Windows 1903 finally allows to name files in Explorer with a leading dot :-)

Error: [$resource:badcfg] Error in resource configuration. Expected response to contain an array but got an object?

Make sure you are sending the proper parameters too. This happened to me after switching to UI-Router.

To fix it, I changed $routeParams to use $stateParams in my controller. The main issue was that $stateParams was no longer sending a proper parameter to the resource.

Use child_process.execSync but keep output in console

You can simply use .toString().

var result = require('child_process').execSync('rsync -avAXz --info=progress2 "/src" "/dest"').toString();
console.log(result);

This has been tested on Node v8.5.0, I'm not sure about previous versions. According to @etov, it doesn't work on v6.3.1 - I'm not sure about in-between.


Edit: Looking back on this, I've realised that it doesn't actually answer the specific question because it doesn't show the output to you 'live' — only once the command has finished running.

However, I'm leaving this answer here because I know quite a few people come across this question just looking for how to print the result of the command after execution.

Java and unlimited decimal places?

I believe that you are looking for the java.lang.BigDecimal class.

<SELECT multiple> - how to allow only one item selected?

If the user should select only one option at once, just remove the "multiple" - make a normal select:

  <select name="mySelect" size="3">
     <option>Foo</option>
     <option>Bar</option>
     <option>Foo Bar</option>
     <option>Bar Foo</option>
  </select>

Fiddle

ORA-28000: the account is locked error getting frequently

One of the reasons of your problem could be the password policy you are using.

And if there is no such policy of yours then check your settings for the password properties in the DEFAULT profile with the following query:

SELECT resource_name, limit
FROM dba_profiles 
WHERE profile = 'DEFAULT'
AND resource_type = 'PASSWORD';

And If required, you just need to change the PASSWORD_LIFE_TIME to unlimited with the following query:

ALTER PROFILE DEFAULT LIMIT PASSWORD_LIFE_TIME UNLIMITED;

And this Link might be helpful for your problem.

How to convert an ArrayList containing Integers to primitive int array?

It bewilders me that we encourage one-off custom methods whenever a perfectly good, well used library like Apache Commons has solved the problem already. Though the solution is trivial if not absurd, it is irresponsible to encourage such a behavior due to long term maintenance and accessibility.

Just go with Apache Commons

Add a column in a table in HIVE QL

You cannot add a column with a default value in Hive. You have the right syntax for adding the column ALTER TABLE test1 ADD COLUMNS (access_count1 int);, you just need to get rid of default sum(max_count). No changes to that files backing your table will happen as a result of adding the column. Hive handles the "missing" data by interpreting NULL as the value for every cell in that column.

So now your have the problem of needing to populate the column. Unfortunately in Hive you essentially need to rewrite the whole table, this time with the column populated. It may be easier to rerun your original query with the new column. Or you could add the column to the table you have now, then select all of its columns plus value for the new column.

You also have the option to always COALESCE the column to your desired default and leave it NULL for now. This option fails when you want NULL to have a meaning distinct from your desired default. It also requires you to depend on always remembering to COALESCE.

If you are very confident in your abilities to deal with the files backing Hive, you could also directly alter them to add your default. In general I would recommend against this because most of the time it will be slower and more dangerous. There might be some case where it makes sense though, so I've included this option for completeness.

How do I authenticate a WebClient request?

This helped me to call API that was using cookie authentication. I have passed authorization in header like this:

request.Headers.Set("Authorization", Utility.Helper.ReadCookie("AuthCookie"));

complete code:

// utility method to read the cookie value:
        public static string ReadCookie(string cookieName)
        {
            var cookies = HttpContext.Current.Request.Cookies;
            var cookie = cookies.Get(cookieName);
            if (cookie != null)
                return cookie.Value;
            return null;
        }

// using statements where you are creating your webclient
using System.Web.Script.Serialization;
using System.Net;
using System.IO;

// WebClient:

var requestUrl = "<API_url>";
var postRequest = new ClassRoom { name = "kushal seth" };

using (var webClient = new WebClient()) {
      JavaScriptSerializer serializer = new JavaScriptSerializer();
      byte[] requestData = Encoding.ASCII.GetBytes(serializer.Serialize(postRequest));
      HttpWebRequest request = WebRequest.Create(requestUrl) as HttpWebRequest;
      request.Method = "POST";
      request.ContentType = "application/json";                        
      request.ContentLength = requestData.Length;
      request.ContentType = "application/json";
      request.Expect = "application/json";
      request.Headers.Set("Authorization", Utility.Helper.ReadCookie("AuthCookie"));
      request.GetRequestStream().Write(requestData, 0, requestData.Length);

      using (var response = (HttpWebResponse)request.GetResponse()) {
         var reader = new StreamReader(response.GetResponseStream());
         var objText = reader.ReadToEnd(); // objText will have the value
      }
}


Mapping composite keys using EF code first

Through Configuration, you can do this:

Model1
{
    int fk_one,
    int fk_two
}

Model2
{
    int pk_one,
    int pk_two,
}

then in the context config

public class MyContext : DbContext
{
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Model1>()
            .HasRequired(e => e.Model2)
            .WithMany(e => e.Model1s)
            .HasForeignKey(e => new { e.fk_one, e.fk_two })
            .WillCascadeOnDelete(false);
    }
}

How do I use Access-Control-Allow-Origin? Does it just go in between the html head tags?

If you use Java and spring MVC you just need to add the following annotation to your method returning your page :

@CrossOrigin(origins = "*")

"*" is to allow your page to be accessible from anywhere. See https://developer.mozilla.org/fr/docs/Web/HTTP/Headers/Access-Control-Allow-Origin for more details about that.

Check if a given key already exists in a dictionary

You can test for the presence of a key in a dictionary, using the in keyword:

d = {'a': 1, 'b': 2}
'a' in d # <== evaluates to True
'c' in d # <== evaluates to False

A common use for checking the existence of a key in a dictionary before mutating it is to default-initialize the value (e.g. if your values are lists, for example, and you want to ensure that there is an empty list to which you can append when inserting the first value for a key). In cases such as those, you may find the collections.defaultdict() type to be of interest.

In older code, you may also find some uses of has_key(), a deprecated method for checking the existence of keys in dictionaries (just use key_name in dict_name, instead).

Github "Updates were rejected because the remote contains work that you do not have locally."

If you are using Visual S2019, Create a new local branch as shown in following, and then push the changes to the repo.

VS2019 local branch

How do I convert hh:mm:ss.000 to milliseconds in Excel?

Let's say that your time value is in cell A1 then in A2 you can put:

=A1*1000*60*60*24

or simply:

=A1*86400000

What I am doing is taking the decimal value of the time and multiply it by 1000 (milliseconds) and 60 (seconds) and 60 (minutes) and 24 (hours).

You will then need to format cell A2 as General for it to be in milliseconds format.

If your time is a text value then use:

=TIMEVALUE(A1)*86400000

UPDATE

Per @dandfra's comment this solution may not work in the Italian version of Excel.

Compiling problems: cannot find crt1.o

To get RHEL 7 64-bit to compile gcc 4.8 32-bit programs, you'll need to do two things.

  1. Make sure all the 32-bit gcc 4.8 development tools are completely installed:

    sudo yum install glibc-devel.i686 libgcc.i686 libstdc++-devel.i686 ncurses-devel.i686
    
  2. Compile programs using the -m32 flag

    gcc pgm.c -m32 -o pgm
    

stolen from here : How to Compile 32-bit Apps on 64-bit RHEL? - I only had to do step 1.

How to change the href for a hyperlink using jQuery

Using

$("a").attr("href", "http://www.google.com/")

will modify the href of all hyperlinks to point to Google. You probably want a somewhat more refined selector though. For instance, if you have a mix of link source (hyperlink) and link target (a.k.a. "anchor") anchor tags:

<a name="MyLinks"></a>
<a href="http://www.codeproject.com/">The CodeProject</a>

...Then you probably don't want to accidentally add href attributes to them. For safety then, we can specify that our selector will only match <a> tags with an existing href attribute:

$("a[href]") //...

Of course, you'll probably have something more interesting in mind. If you want to match an anchor with a specific existing href, you might use something like this:

$("a[href='http://www.google.com/']").attr('href', 'http://www.live.com/')

This will find links where the href exactly matches the string http://www.google.com/. A more involved task might be matching, then updating only part of the href:

$("a[href^='http://stackoverflow.com']")
   .each(function()
   { 
      this.href = this.href.replace(/^http:\/\/beta\.stackoverflow\.com/, 
         "http://stackoverflow.com");
   });

The first part selects only links where the href starts with http://stackoverflow.com. Then, a function is defined that uses a simple regular expression to replace this part of the URL with a new one. Note the flexibility this gives you - any sort of modification to the link could be done here.

finished with non zero exit value

Make sure that your min/targetSdkVersions are the same in build.gradle and manifest (if exist). Also check for buildToolsVersion in all your modules - it must be the same.

Remove Backslashes from Json Data in JavaScript

Your string is invalid, but assuming it was valid, you'd have to do:

var finalData = str.replace(/\\/g, "");

When you want to replace all the occurences with .replace, the first parameter must be a regex, if you supply a string, only the first occurrence will be replaced, that's why your replace wouldn't work.

Cheers

How can I search sub-folders using glob.glob module?

configfiles = glob.glob('C:/Users/sam/Desktop/**/*.txt")

Doesn't works for all cases, instead use glob2

configfiles = glob2.glob('C:/Users/sam/Desktop/**/*.txt")

Accessing an array out of bounds gives no error, why?

It's undefined behavior as far as I know. Run a larger program with that and it will crash somewhere along the way. Bounds checking is not a part of raw arrays (or even std::vector).

Use std::vector with std::vector::iterator's instead so you don't have to worry about it.

Edit:

Just for fun, run this and see how long until you crash:

int main()
{
   int array[1];

   for (int i = 0; i != 100000; i++)
   {
       array[i] = i;
   }

   return 0; //will be lucky to ever reach this
}

Edit2:

Don't run that.

Edit3:

OK, here is a quick lesson on arrays and their relationships with pointers:

When you use array indexing, you are really using a pointer in disguise (called a "reference"), that is automatically dereferenced. This is why instead of *(array[1]), array[1] automatically returns the value at that value.

When you have a pointer to an array, like this:

int array[5];
int *ptr = array;

Then the "array" in the second declaration is really decaying to a pointer to the first array. This is equivalent behavior to this:

int *ptr = &array[0];

When you try to access beyond what you allocated, you are really just using a pointer to other memory (which C++ won't complain about). Taking my example program above, that is equivalent to this:

int main()
{
   int array[1];
   int *ptr = array;

   for (int i = 0; i != 100000; i++, ptr++)
   {
       *ptr++ = i;
   }

   return 0; //will be lucky to ever reach this
}

The compiler won't complain because in programming, you often have to communicate with other programs, especially the operating system. This is done with pointers quite a bit.

How to use the TextWatcher class in Android?

Create custom TextWatcher subclass:

public class CustomWatcher implements TextWatcher {

    private boolean mWasEdited = false;

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

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

    }

    @Override
    public void afterTextChanged(Editable s) {

        if (mWasEdited){

            mWasEdited = false;
            return;
        }

        // get entered value (if required)
        String enteredValue  = s.toString();

        String newValue = "new value";

        // don't get trap into infinite loop
        mWasEdited = true;
        // just replace entered value with whatever you want
        s.replace(0, s.length(), newValue);

    }
}

Set listener for your EditText:

mTargetEditText.addTextChangedListener(new CustomWatcher());

How do I create the small icon next to the website tab for my site?

This is for the icon in the browser (most of the sites omit the type):

<link rel="icon" type="image/vnd.microsoft.icon"
     href="http://example.com/favicon.ico" />

or

<link rel="icon" type="image/png"
     href="http://example.com/image.png" />

or

<link rel="apple-touch-icon"
     href="http://example.com//apple-touch-icon.png">

for the shortcut icon:

<link rel="shortcut icon"
     href="http://example.com/favicon.ico" />

Place them in the <head></head> section.

Edit may 2019 some additional examples from MDN

How to declare a vector of zeros in R

You can also use the matrix command, to create a matrix with n lines and m columns, filled with zeros.

matrix(0, n, m)

How to do exponential and logarithmic curve fitting in Python? I found only polynomial fitting

You can also fit a set of a data to whatever function you like using curve_fit from scipy.optimize. For example if you want to fit an exponential function (from the documentation):

import numpy as np
import matplotlib.pyplot as plt
from scipy.optimize import curve_fit

def func(x, a, b, c):
    return a * np.exp(-b * x) + c

x = np.linspace(0,4,50)
y = func(x, 2.5, 1.3, 0.5)
yn = y + 0.2*np.random.normal(size=len(x))

popt, pcov = curve_fit(func, x, yn)

And then if you want to plot, you could do:

plt.figure()
plt.plot(x, yn, 'ko', label="Original Noised Data")
plt.plot(x, func(x, *popt), 'r-', label="Fitted Curve")
plt.legend()
plt.show()

(Note: the * in front of popt when you plot will expand out the terms into the a, b, and c that func is expecting.)

XAMPP - Error: MySQL shutdown unexpectedly

** -> "xampp->mysql->data" cut all files from data folder and paste to another folder

-> now restart mysql

-> paste all folders from your folder to myslq->data folder

and also paste ib_logfile0.ib_logfile1 , ibdata1 into data folder from your folder.

your database and your data is now available in phpmyadmin..**

What is SYSNAME data type in SQL Server?

Another use case is when using the SQL Server 2016+ functionality of AT TIME ZONE

The below statement will return a date converted to GMT

SELECT 
CONVERT(DATETIME, SWITCHOFFSET([ColumnA], DATEPART(TZOFFSET, [ColumnA] AT TIME ZONE 'GMT Standard Time')))

If you want to pass the time zone as a variable, say:

SELECT 
CONVERT(DATETIME, SWITCHOFFSET([ColumnA], DATEPART(TZOFFSET, [ColumnA] AT TIME ZONE @TimeZone)))

then that variable needs to be of the type sysname (declaring it as varchar will cause an error).

How to embed small icon in UILabel

Try dragging a UIView onto the screen in IB. From there you can drag a UIImageView and UILabel into the view you just created. Set the image of the UIImageView in the properties inspector as the custom bullet image (which you will have to add to your project by dragging it into the navigation pane) and you can write some text in the label.

How to git reset --hard a subdirectory?

Try changing

git checkout -- a

to

git checkout -- `git ls-files -m -- a`

Since version 1.7.0, Git's ls-files honors the skip-worktree flag.

Running your test script (with some minor tweaks changing git commit... to git commit -q and git status to git status --short) outputs:

Initialized empty Git repository in /home/user/repo/.git/
After read-tree:
a/a/aa
a/b/ab
b/a/ba
After modifying:
b/a/ba
 D a/a/aa
 D a/b/ab
 M b/a/ba
After checkout:
 M b/a/ba
a/a/aa
a/c/ac
a/b/ab
b/a/ba

Running your test script with the proposed checkout change outputs:

Initialized empty Git repository in /home/user/repo/.git/
After read-tree:
a/a/aa
a/b/ab
b/a/ba
After modifying:
b/a/ba
 D a/a/aa
 D a/b/ab
 M b/a/ba
After checkout:
 M b/a/ba
a/a/aa
a/b/ab
b/a/ba

HTTP 400 (bad request) for logical error, not malformed request syntax

Status 422 (RFC 4918, Section 11.2) comes to mind:

The 422 (Unprocessable Entity) status code means the server understands the content type of the request entity (hence a 415(Unsupported Media Type) status code is inappropriate), and the syntax of the request entity is correct (thus a 400 (Bad Request) status code is inappropriate) but was unable to process the contained instructions. For example, this error condition may occur if an XML request body contains well-formed (i.e., syntactically correct), but semantically erroneous, XML instructions.

This view is not constrained

Right-click on the widget and choose "center" -> "horizontally". Then choose "center"->"vertically".

Stacked bar chart

You said :

Maybe my data.frame is not in a good format?

Yes this is true. Your data is in the wide format You need to put it in the long format. Generally speaking, long format is better for variables comparison.

Using reshape2 for example , you do this using melt:

dat.m <- melt(dat,id.vars = "Rank") ## just melt(dat) should work

Then you get your barplot:

ggplot(dat.m, aes(x = Rank, y = value,fill=variable)) +
    geom_bar(stat='identity')

But using lattice and barchart smart formula notation , you don't need to reshape your data , just do this:

barchart(F1+F2+F3~Rank,data=dat)

C#: New line and tab characters in strings

Use:

sb.AppendLine();
sb.Append("\t");

for better portability. Environment.NewLine may not necessarily be \n; Windows uses \r\n, for example.

Function stoi not declared

stoi is available "since C++11". Make sure your compiler is up to date.

You can try atoi(hours0.c_str()) instead.

how to bind img src in angular 2 in ngFor?

Angular 2, 4 and Angular 5 compatible!

You have provided so few details, so I'll try to answer your question without them.

You can use Interpolation:

<img src={{imagePath}} />

Or you can use a template expression:

<img [src]="imagePath" />

In a ngFor loop it might look like this:

<div *ngFor="let student of students">
   <img src={{student.ImagePath}} />
</div>

Interview question: Check if one string is a rotation of other string

I guess its better to do this in Java:

boolean isRotation(String s1,String s2) {
    return (s1.length() == s2.length()) && (s1+s1).contains(s2);
}

In Perl I would do:

sub isRotation {
 my($string1,$string2) = @_;
 return length($string1) == length($string2) && ($string1.$string1)=~/$string2/;
}

or even better using the index function instead of the regex:

sub isRotation {
 my($string1,$string2) = @_;
 return length($string1) == length($string2) && index($string2,$string1.$string1) != -1;
}

Disable Tensorflow debugging information

To add some flexibility here, you can achieve more fine-grained control over the level of logging by writing a function that filters out messages however you like:

logging.getLogger('tensorflow').addFilter(my_filter_func)

where my_filter_func accepts a LogRecord object as input [LogRecord docs] and returns zero if you want the message thrown out; nonzero otherwise.

Here's an example filter that only keeps every nth info message (Python 3 due to the use of nonlocal here):

def keep_every_nth_info(n):
    i = -1
    def filter_record(record):
        nonlocal i
        i += 1
        return int(record.levelname != 'INFO' or i % n == 0)
    return filter_record

# Example usage for TensorFlow:
logging.getLogger('tensorflow').addFilter(keep_every_nth_info(5))

All of the above has assumed that TensorFlow has set up its logging state already. You can ensure this without side effects by calling tf.logging.get_verbosity() before adding a filter.

Get year, month or day from numpy datetime64

Anon's answer works great for me, but I just need to modify the statement for days

from:

days = dates - dates.astype('datetime64[M]') + 1

to:

days = dates.astype('datetime64[D]') - dates.astype('datetime64[M]') + 1

ArrayIndexOutOfBoundsException when using the ArrayList's iterator

Am I doing that right, as far as iterating through the Arraylist goes?

No: by calling iterator twice in each iteration, you're getting new iterators all the time.

The easiest way to write this loop is using the for-each construct:

for (String s : arrayList)
    if (s.equals(value))
        // ...

As for

java.lang.ArrayIndexOutOfBoundsException: -1

You just tried to get element number -1 from an array. Counting starts at zero.

Printing string variable in Java

You are printing the wrong value. Instead if the string you print the scanners object. Try this

Scanner input = new Scanner(System.in);
String s = input.next();
System.out.println(s);

dbms_lob.getlength() vs. length() to find blob size in oracle

length and dbms_lob.getlength return the number of characters when applied to a CLOB (Character LOB). When applied to a BLOB (Binary LOB), dbms_lob.getlength will return the number of bytes, which may differ from the number of characters in a multi-byte character set.

As the documentation doesn't specify what happens when you apply length on a BLOB, I would advise against using it in that case. If you want the number of bytes in a BLOB, use dbms_lob.getlength.

Convert any object to a byte[]

checkout this article :http://www.morgantechspace.com/2013/08/convert-object-to-byte-array-and-vice.html

Use the below code

// Convert an object to a byte array
private byte[] ObjectToByteArray(Object obj)
{
    if(obj == null)
        return null;

    BinaryFormatter bf = new BinaryFormatter();
    MemoryStream ms = new MemoryStream();
    bf.Serialize(ms, obj);

    return ms.ToArray();
}

// Convert a byte array to an Object
private Object ByteArrayToObject(byte[] arrBytes)
{
    MemoryStream memStream = new MemoryStream();
    BinaryFormatter binForm = new BinaryFormatter();
    memStream.Write(arrBytes, 0, arrBytes.Length);
    memStream.Seek(0, SeekOrigin.Begin);
    Object obj = (Object) binForm.Deserialize(memStream);

    return obj;
}

Raise warning in Python without interrupting program

By default, unlike an exception, a warning doesn't interrupt.

After import warnings, it is possible to specify a Warnings class when generating a warning. If one is not specified, it is literally UserWarning by default.

>>> warnings.warn('This is a default warning.')
<string>:1: UserWarning: This is a default warning.

To simply use a preexisting class instead, e.g. DeprecationWarning:

>>> warnings.warn('This is a particular warning.', DeprecationWarning)
<string>:1: DeprecationWarning: This is a particular warning.

Creating a custom warning class is similar to creating a custom exception class:

>>> class MyCustomWarning(UserWarning):
...     pass
... 
... warnings.warn('This is my custom warning.', MyCustomWarning)

<string>:1: MyCustomWarning: This is my custom warning.

For testing, consider assertWarns or assertWarnsRegex.


As an alternative, especially for standalone applications, consider the logging module. It can log messages having a level of debug, info, warning, error, etc. Log messages having a level of warning or higher are by default printed to stderr.

Facebook Open Graph not clearing cache

The OG thumbnail does not seem to refresh even if passing the fbrefresh variable. To update this without waiting for automated clearing you'll need to change the filename of the thumbnail associated meta tag value and refresh.

Git Cherry-Pick and Conflicts

Also, to complete what @claudio said, when cherry-picking you can also use a merging strategy.

So you could something like this git cherry-pick --strategy=recursive -X theirs commit or git cherry-pick --strategy=recursive -X ours commit

Difference between / and /* in servlet mapping url pattern

Perhaps you need to know how urls are mapped too, since I suffered 404 for hours. There are two kinds of handlers handling requests. BeanNameUrlHandlerMapping and SimpleUrlHandlerMapping. When we defined a servlet-mapping, we are using SimpleUrlHandlerMapping. One thing we need to know is these two handlers share a common property called alwaysUseFullPath which defaults to false.

false here means Spring will not use the full path to mapp a url to a controller. What does it mean? It means when you define a servlet-mapping:

<servlet-mapping>
    <servlet-name>viewServlet</servlet-name>
    <url-pattern>/perfix/*</url-pattern>
</servlet-mapping>

the handler will actually use the * part to find the controller. For example, the following controller will face a 404 error when you request it using /perfix/api/feature/doSomething

@Controller()
@RequestMapping("/perfix/api/feature")
public class MyController {
    @RequestMapping(value = "/doSomething", method = RequestMethod.GET) 
    @ResponseBody
    public String doSomething(HttpServletRequest request) {
        ....
    }
}

It is a perfect match, right? But why 404. As mentioned before, default value of alwaysUseFullPath is false, which means in your request, only /api/feature/doSomething is used to find a corresponding Controller, but there is no Controller cares about that path. You need to either change your url to /perfix/perfix/api/feature/doSomething or remove perfix from MyController base @RequestingMapping.

IllegalArgumentException or NullPointerException for a null parameter?

Some collections assume that null is rejected using NullPointerException rather than IllegalArgumentException. For example, if you compare a set containing null to a set that rejects null, the first set will call containsAll on the other and catch its NullPointerException -- but not IllegalArgumentException. (I'm looking at the implementation of AbstractSet.equals.)

You could reasonably argue that using unchecked exceptions in this way is an antipattern, that comparing collections that contain null to collections that can't contain null is a likely bug that really should produce an exception, or that putting null in a collection at all is a bad idea. Nevertheless, unless you're willing to say that equals should throw an exception in such a case, you're stuck remembering that NullPointerException is required in certain circumstances but not in others. ("IAE before NPE except after 'c'...")

How to determine the current iPhone/device model?

There is a helper library for this.

Swift 5

pod 'DeviceKit', '~> 2.0'

Swift 4.0 - Swift 4.2

pod 'DeviceKit', '~> 1.3'

if you just want to determine the model and make something accordingly.

You can use like that :

let isIphoneX = Device().isOneOf([.iPhoneX, .simulator(.iPhoneX)])

In a function :

func isItIPhoneX() -> Bool {
    let device = Device()
    let check = device.isOneOf([.iPhoneX, .iPhoneXr , .iPhoneXs , .iPhoneXsMax ,
                                .simulator(.iPhoneX), .simulator(.iPhoneXr) , .simulator(.iPhoneXs) , .simulator(.iPhoneXsMax) ])
    return check
}

How to send email in ASP.NET C#

Try the following :

try
{
    var fromEmailAddress =  ConfigurationManager.AppSettings["FromEmailAddress"].ToString();
    var fromEmailDisplayName = ConfigurationManager.AppSettings["FromEmailDisplayName"].ToString();
    var fromEmailPassword = ConfigurationManager.AppSettings["FromEmailPassword"].ToString();
    var smtpHost = ConfigurationManager.AppSettings["SMTPHost"].ToString();
    var smtpPort = ConfigurationManager.AppSettings["SMTPPort"].ToString();

    string body = "Your registration has been done successfully. Thank you.";
    MailMessage message = new MailMessage(new MailAddress(fromEmailAddress, fromEmailDisplayName), new MailAddress(ud.LoginId, ud.FullName));
    message.Subject = "Thank You For Your Registration";
    message.IsBodyHtml = true;
    message.Body = body;

    var client = new SmtpClient();
    client.Credentials = new NetworkCredential(fromEmailAddress, fromEmailPassword);
    client.Host = smtpHost;
    client.EnableSsl = true;
    client.Port = !string.IsNullOrEmpty(smtpPort) ? Convert.ToInt32(smtpPort) : 0;
    client.Send(message);
}
catch (Exception ex)
{
    throw (new Exception("Mail send failed to loginId " + ud.LoginId + ", though registration done."));
}

And then in you web.config add the following in between

<!--Email Config-->
<add key="FromEmailAddress" value="sender emailaddress"/>
<add key="FromEmailDisplayName" value="Display Name"/>
<add key="FromEmailPassword" value="sender Password"/>
<add key="SMTPHost" value="smtp-proxy.tm.net.my"/>
<add key="SMTPPort" value="smptp Port"/>

How do SETLOCAL and ENABLEDELAYEDEXPANSION work?

A real problem often exists because any variables set inside will not be exported when that batch file finishes. So its not possible to export, which caused us issues. As a result, I just set the registry to ALWAYS used delayed expansion (I don't know why it's not the default, could be speed or legacy compatibility issue.)

How can I check if a string is a number?

Yes there is

int temp;
int.TryParse("141241", out temp) = true
int.TryParse("232a23", out temp) = false
int.TryParse("12412a", out temp) = false

Hope this helps.

Angular 2 filter/search list

Currently ng2-search-filter simplify this works.

By directive

<tr *ngFor="let item of items | filter:searchText">
  <td>{{item.name}}</td>
</tr>

Or programmatically

let itemsFiltered = new Ng2SearchPipe().transform(items, searchText);

Practical example: https://angular-search-filter.stackblitz.io

Copying PostgreSQL database to another server

pg_dump the_db_name > the_backup.sql

Then copy the backup to your development server, restore with:

psql the_new_dev_db < the_backup.sql

Print all day-dates between two dates

Using a list comprehension:

from datetime import date, timedelta

d1 = date(2008,8,15)
d2 = date(2008,9,15)

# this will give you a list containing all of the dates
dd = [d1 + timedelta(days=x) for x in range((d2-d1).days + 1)]

for d in dd:
    print d

# you can't join dates, so if you want to use join, you need to
# cast to a string in the list comprehension:
ddd = [str(d1 + timedelta(days=x)) for x in range((d2-d1).days + 1)]
# now you can join
print "\n".join(ddd)

How can I change an element's class with JavaScript?

Here's a toggleClass to toggle/add/remove a class on an element:

// If newState is provided add/remove theClass accordingly, otherwise toggle theClass
function toggleClass(elem, theClass, newState) {
    var matchRegExp = new RegExp('(?:^|\\s)' + theClass + '(?!\\S)', 'g');
    var add=(arguments.length>2 ? newState : (elem.className.match(matchRegExp) == null));

    elem.className=elem.className.replace(matchRegExp, ''); // clear all
    if (add) elem.className += ' ' + theClass;
}

see jsfiddle

also see my answer here for creating a new class dynamically

How do I call a SQL Server stored procedure from PowerShell?

Use sqlcmd instead of osql if it's a 2005 database

Android: keeping a background service alive (preventing process death)

I'm working on an app and face issue of killing my service by on app kill. I researched on google and found that I have to make it foreground. following is the code:

public class UpdateLocationAndPrayerTimes extends Service {

 Context context;
@Override
public void onCreate() {
    super.onCreate();
    context = this;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    StartForground();
    return START_STICKY;
}

@Override
public void onDestroy() {


    super.onDestroy();
}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}


private void StartForground() {
    LocationChangeDetector locationChangeDetector = new LocationChangeDetector(context);
    locationChangeDetector.getLatAndLong();
    Notification notification = new NotificationCompat.Builder(this)
            .setOngoing(false)
            .setSmallIcon(android.R.color.transparent)

            //.setSmallIcon(R.drawable.picture)
            .build();
    startForeground(101,  notification);

    }
}

hops that it may helps!!!!

Can't change table design in SQL Server 2008

The answer is on the MSDN site:

The Save (Not Permitted) dialog box warns you that saving changes is not permitted because the changes you have made require the listed tables to be dropped and re-created.

The following actions might require a table to be re-created:

  • Adding a new column to the middle of the table
  • Dropping a column
  • Changing column nullability
  • Changing the order of the columns
  • Changing the data type of a column

EDIT 1:

Additional useful informations from here:

To change the Prevent saving changes that require the table re-creation option, follow these steps:

  1. Open SQL Server Management Studio (SSMS).
  2. On the Tools menu, click Options.
  3. In the navigation pane of the Options window, click Designers.
  4. Select or clear the Prevent saving changes that require the table re-creation check box, and then click OK.

Note If you disable this option, you are not warned when you save the table that the changes that you made have changed the metadata structure of the table. In this case, data loss may occur when you save the table.

Risk of turning off the "Prevent saving changes that require table re-creation" option

Although turning off this option can help you avoid re-creating a table, it can also lead to changes being lost. For example, suppose that you enable the Change Tracking feature in SQL Server 2008 to track changes to the table. When you perform an operation that causes the table to be re-created, you receive the error message that is mentioned in the "Symptoms" section. However, if you turn off this option, the existing change tracking information is deleted when the table is re-created. Therefore, we recommend that you do not work around this problem by turning off the option.

Settings, screen shot

How to check the multiple permission at single request in Android M?

First initialize permission request code

public  static final int PERMISSIONS_MULTIPLE_REQUEST = 123;

Check android version

 private void checkAndroidVersion() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        checkPermission();

    } else {
        // write your logic here
    }

}

check multiple permission code

 private void checkPermission() {
    if (ContextCompat.checkSelfPermission(getActivity(),
            Manifest.permission.READ_EXTERNAL_STORAGE) + ContextCompat
            .checkSelfPermission(getActivity(),
                    Manifest.permission.CAMERA)
            != PackageManager.PERMISSION_GRANTED) {

        if (ActivityCompat.shouldShowRequestPermissionRationale
                (getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE) ||
                ActivityCompat.shouldShowRequestPermissionRationale
                        (getActivity(), Manifest.permission.CAMERA)) {

      Snackbar.make(getActivity().findViewById(android.R.id.content),
                    "Please Grant Permissions to upload profile photo",
                    Snackbar.LENGTH_INDEFINITE).setAction("ENABLE",
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            requestPermissions(
                                    new String[]{Manifest.permission
                                            .READ_EXTERNAL_STORAGE, Manifest.permission.CAMERA},
                                    PERMISSIONS_MULTIPLE_REQUEST);
                        }
                    }).show();
        } else {
            requestPermissions(
                    new String[]{Manifest.permission
                            .READ_EXTERNAL_STORAGE, Manifest.permission.CAMERA},
                    PERMISSIONS_MULTIPLE_REQUEST);
        }
    } else {
        // write your logic code if permission already granted
    }
}

call back method after grant permission by user

@Override
public void onRequestPermissionsResult(int requestCode,
                                       @NonNull String[] permissions, @NonNull int[] grantResults) {

    switch (requestCode) {
        case PERMISSIONS_MULTIPLE_REQUEST:
            if (grantResults.length > 0) {
               boolean cameraPermission = grantResults[1] == PackageManager.PERMISSION_GRANTED;
               boolean readExternalFile = grantResults[0] == PackageManager.PERMISSION_GRANTED;

                if(cameraPermission && readExternalFile)
                {
                    // write your logic here 
                } else {
                    Snackbar.make(getActivity().findViewById(android.R.id.content),
                        "Please Grant Permissions to upload profile photo",
                        Snackbar.LENGTH_INDEFINITE).setAction("ENABLE",
                        new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                requestPermissions(
                                        new String[]{Manifest.permission
                                                .READ_EXTERNAL_STORAGE, Manifest.permission.CAMERA},
                                        PERMISSIONS_MULTIPLE_REQUEST);
                            }
                        }).show();
                }
           }
           break;
    }
}

How to check if type of a variable is string?

In Python 3.x or Python 2.7.6

if type(x) == str:

Huge performance difference when using group by vs distinct

The two queries express the same question. Apparently the query optimizer chooses two different execution plans. My guess would be that the distinct approach is executed like:

  • Copy all business_key values to a temporary table
  • Sort the temporary table
  • Scan the temporary table, returning each item that is different from the one before it

The group by could be executed like:

  • Scan the full table, storing each value of business key in a hashtable
  • Return the keys of the hashtable

The first method optimizes for memory usage: it would still perform reasonably well when part of the temporary table has to be swapped out. The second method optimizes for speed, but potentially requires a large amount of memory if there are a lot of different keys.

Since you either have enough memory or few different keys, the second method outperforms the first. It's not unusual to see performance differences of 10x or even 100x between two execution plans.

Iterate over object keys in node.js

Also remember that you can pass a second argument to the .forEach() function specifying the object to use as the this keyword.

// myOjbect is the object you want to iterate.
// Notice the second argument (secondArg) we passed to .forEach.
Object.keys(myObject).forEach(function(element, key, _array) {
  // element is the name of the key.
  // key is just a numerical value for the array
  // _array is the array of all the keys

  // this keyword = secondArg
  this.foo;
  this.bar();
}, secondArg);

Unit Testing: DateTime.Now

One clean way to do this is to inject VirtualTime. It allows you to control time. First install VirtualTime

Install-Package VirtualTime

That allows to, for example, make time that moves 5 times faster on all calls to DateTime.Now or UtcNow

var DateTime = DateTime.Now.ToVirtualTime(5);

To make time move slower , eg 5 times slower do

var DateTime = DateTime.Now.ToVirtualTime(0.5);

To make time stand still do

var DateTime = DateTime.Now.ToVirtualTime(0);

Moving backwards in time is not tested yet

Here are a sample test:

[TestMethod]
public void it_should_make_time_move_faster()
{
    int speedOfTimePerMs = 1000;
    int timeToPassMs = 3000;
    int expectedElapsedVirtualTime = speedOfTimePerMs * timeToPassMs;
    DateTime whenTimeStarts = DateTime.Now;
    ITime time = whenTimeStarts.ToVirtualTime(speedOfTimePerMs);
    Thread.Sleep(timeToPassMs);
    DateTime expectedTime = DateTime.Now.AddMilliseconds(expectedElapsedVirtualTime - timeToPassMs);
    DateTime virtualTime = time.Now;

    Assert.IsTrue(TestHelper.AreEqualWithinMarginOfError(expectedTime, virtualTime, MarginOfErrorMs));
}

You can check out more tests here:

https://github.com/VirtualTime/VirtualTime/blob/master/VirtualTimeLib.Tests/when_virtual_time_is_used.cs

What DateTime.Now.ToVirtualTime extension gives you is an instance of ITime which you pass to a method / class that depends on ITime. some DateTime.Now.ToVirtualTime is setup in the DI container of your choice

Here is another example injecting into a class contrustor

public class AlarmClock
{
    private ITime DateTime;
    public AlarmClock(ITime dateTime, int numberOfHours)
    {
        DateTime = dateTime;
        SetTime = DateTime.UtcNow.AddHours(numberOfHours);
        Task.Run(() =>
        {
            while (!IsAlarmOn)
            {
                IsAlarmOn = (SetTime - DateTime.UtcNow).TotalMilliseconds < 0;
            }
        });
    }
    public DateTime SetTime { get; set; }
    public bool IsAlarmOn { get; set; }
}

[TestMethod]
public void it_can_be_injected_as_a_dependency()
{
    //virtual time has to be 1000*3.75 faster to get to an hour 
    //in 1000 ms real time
    var dateTime = DateTime.Now.ToVirtualTime(1000 * 3.75);
    var numberOfHoursBeforeAlarmSounds = 1;
    var alarmClock = new AlarmClock(dateTime, numberOfHoursBeforeAlarmSounds);
    Assert.IsFalse(alarmClock.IsAlarmOn);
    System.Threading.Thread.Sleep(1000);
    Assert.IsTrue(alarmClock.IsAlarmOn);
}

The easiest way to replace white spaces with (underscores) _ in bash

You can do it using only the shell, no need for tr or sed

$ str="This is just a test"
$ echo ${str// /_}
This_is_just_a_test

How do I link object files in C? Fails with "Undefined symbols for architecture x86_64"

You could compile and link in one command:

gcc file1.c file2.c -o myprogram

And run with:

./myprogram

But to answer the question as asked, simply pass the object files to gcc:

gcc file1.o file2.o -o myprogram

How to write a PHP ternary operator

echo ($result ->vocation == 1) ? 'Sorcerer'
        : ($result->vocation == 2) ? 'Druid'
           :  ($result->vocation == 3) ? 'Paladin'
                    ....

;

It’s kind of ugly. You should stick with normal if statements.

Checking for empty result (php, pdo, mysql)

If you have the option of using fetchAll() then if there are no rows returned it will just be and empty array.

count($sql->fetchAll(PDO::FETCH_ASSOC))

will return the number of rows returned.

Java rounding up to an int using Math.ceil

In Java adding a .0 will make it a double...

int total = (int) Math.ceil(157.0 / 32.0);

How to convert Javascript datetime to C# datetime?

I think you can use the TimeZoneInfo....to convert the datetime....

    static void Main(string[] args)
    {
        long time = 1310522400000;
        DateTime dt_1970 = new DateTime(1970, 1, 1);
        long tricks_1970 = dt_1970.Ticks;
        long time_tricks = tricks_1970 + time * 10000;
        DateTime dt = new DateTime(time_tricks);

        Console.WriteLine(dt.ToShortDateString()); // result : 7/13
        dt = TimeZoneInfo.ConvertTimeToUtc(dt);

        Console.WriteLine(dt.ToShortDateString());  // result : 7/12
        Console.Read();
    }

Set min-width in HTML table's <td>

<table style="border:2px solid #ddedde">
    <tr>
        <td style="border:2px solid #ddedde;width:50%">a</td>
        <td style="border:2px solid #ddedde;width:20%">b</td>
        <td style="border:2px solid #ddedde;width:30%">c</td>
    </tr>
    <tr>
        <td style="border:2px solid #ddedde;width:50%">a</td>
        <td style="border:2px solid #ddedde;width:20%">b</td>
        <td style="border:2px solid #ddedde;width:30%">c</td>
    </tr>
</table>

How to correctly implement custom iterators and const_iterators?

Check this below code, it works

#define MAX_BYTE_RANGE 255

template <typename T>
class string
{
public:
    typedef char *pointer;
    typedef const char *const_pointer;
    typedef __gnu_cxx::__normal_iterator<pointer, string> iterator;
    typedef __gnu_cxx::__normal_iterator<const_pointer, string> const_iterator;

    string() : length(0)
    {
    }
    size_t size() const
    {
        return length;
    }
    void operator=(const_pointer value)
    {
        if (value == nullptr)
            throw std::invalid_argument("value cannot be null");
        auto count = strlen(value);
        if (count > 0)
            _M_copy(value, count);
    }
    void operator=(const string &value)
    {
        if (value.length != 0)
            _M_copy(value.buf, value.length);
    }
    iterator begin()
    {
        return iterator(buf);
    }
    iterator end()
    {
        return iterator(buf + length);
    }
    const_iterator begin() const
    {
        return const_iterator(buf);
    }
    const_iterator end() const
    {
        return const_iterator(buf + length);
    }
    const_pointer c_str() const
    {
        return buf;
    }
    ~string()
    {
    }

private:
    unsigned char length;
    T buf[MAX_BYTE_RANGE];

    void _M_copy(const_pointer value, size_t count)
    {
        memcpy(buf, value, count);
        length = count;
    }
};

What command means "do nothing" in a conditional in Bash?

Although I'm not answering the original question concering the no-op command, many (if not most) problems when one may think "in this branch I have to do nothing" can be bypassed by simply restructuring the logic so that this branch won't occur.

I try to give a general rule by using the OPs example

do nothing when $a is greater than "10", print "1" if $a is less than "5", otherwise, print "2"

we have to avoid a branch where $a gets more than 10, so $a < 10 as a general condition can be applied to every other, following condition.

In general terms, when you say do nothing when X, then rephrase it as avoid a branch where X. Usually you can make the avoidance happen by simply negating X and applying it to all other conditions.

So the OPs example with the rule applied may be restructured as:

if [ "$a" -lt 10 ] && [ "$a" -le 5 ]
then
    echo "1"
elif [ "$a" -lt 10 ]
then
    echo "2"
fi

Just a variation of the above, enclosing everything in the $a < 10 condition:

if [ "$a" -lt 10 ]
then
    if [ "$a" -le 5 ]
    then
        echo "1"
    else
        echo "2"
    fi
fi

(For this specific example @Flimzys restructuring is certainly better, but I wanted to give a general rule for all the people searching how to do nothing.)

Installing Bower on Ubuntu

on Ubuntu 12.04 and the packaged version of NodeJs is too old to install Bower using the PPA

sudo add-apt-repository ppa:chris-lea/node.js 
sudo apt-get update
sudo apt-get -y install nodejs

When this has installed, check the version:

npm --version
1.4.3

Now install Bower:

sudo npm install -g bower

This will fetch and install Bower globally.

How do I use Assert.Throws to assert the type of the exception?

Assert.Throws returns the exception that's thrown which lets you assert on the exception.

var ex = Assert.Throws<Exception>(() => user.MakeUserActive());
Assert.That(ex.Message, Is.EqualTo("Actual exception message"));

So if no exception is thrown, or an exception of the wrong type is thrown, the first Assert.Throws assertion will fail. However if an exception of the correct type is thrown then you can now assert on the actual exception that you've saved in the variable.

By using this pattern you can assert on other things than the exception message, e.g. in the case of ArgumentException and derivatives, you can assert that the parameter name is correct:

var ex = Assert.Throws<ArgumentNullException>(() => foo.Bar(null));
Assert.That(ex.ParamName, Is.EqualTo("bar"));

You can also use the fluent API for doing these asserts:

Assert.That(() => foo.Bar(null), 
Throws.Exception
  .TypeOf<ArgumentNullException>()
  .With.Property("ParamName")
  .EqualTo("bar"));

or alternatively

Assert.That(
    Assert.Throws<ArgumentNullException>(() =>
        foo.Bar(null)
    .ParamName,
Is.EqualTo("bar"));

A little tip when asserting on exception messages is to decorate the test method with the SetCultureAttribute to make sure that the thrown message is using the expected culture. This comes into play if you store your exception messages as resources to allow for localization.

Sending event when AngularJS finished loading

I have come up with a solution that is relatively accurate at evaluating when the angular initialisation is complete.

The directive is:

.directive('initialisation',['$rootScope',function($rootScope) {
            return {
                restrict: 'A',
                link: function($scope) {
                    var to;
                    var listener = $scope.$watch(function() {
                        clearTimeout(to);
                        to = setTimeout(function () {
                            console.log('initialised');
                            listener();
                            $rootScope.$broadcast('initialised');
                        }, 50);
                    });
                }
            };
        }]);

That can then just be added as an attribute to the body element and then listened for using $scope.$on('initialised', fn)

It works by assuming that the application is initialised when there are no more $digest cycles. $watch is called every digest cycle and so a timer is started (setTimeout not $timeout so a new digest cycle is not triggered). If a digest cycle does not occur within the timeout then the application is assumed to have initialised.

It is obviously not as accurate as satchmoruns solution (as it is possible a digest cycle takes longer than the timeout) but my solution doesn't need you to keep track of the modules which makes it that much easier to manage (particularly for larger projects). Anyway, seems to be accurate enough for my requirements. Hope it helps.

How do you get the contextPath from JavaScript, the right way?

Based on the discussion in the comments (particularly from BalusC), it's probably not worth doing anything more complicated than this:

<script>var ctx = "${pageContext.request.contextPath}"</script>

Command prompt won't change directory to another drive

you should use a /d before path as below :

cd /d e:\

How to center icon and text in a android button with width set to "fill parent"

I recently bumped into the same problem. Tried to find a cheaper solution so came up with this.

   <LinearLayout
        android:id="@+id/linearButton"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/selector_button_translucent_ab_color"
        android:clickable="true"
        android:descendantFocusability="blocksDescendants"
        android:gravity="center"
        android:orientation="horizontal" >

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="@string/app_name"
            android:src="@drawable/ic_launcher" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/app_name"
            android:textColor="@android:color/white" />
    </LinearLayout>

Then just call the OnClickListener on LinearLayout.

Hope this helps someone as it seems like a very common problem. :)

Deleting DataFrame row in Pandas based on column value

But for any future bypassers you could mention that df = df[df.line_race != 0] doesn't do anything when trying to filter for None/missing values.

Does work:

df = df[df.line_race != 0]

Doesn't do anything:

df = df[df.line_race != None]

Does work:

df = df[df.line_race.notnull()]

Extract date (yyyy/mm/dd) from a timestamp in PostgreSQL

In postgres simply : TO_CHAR(timestamp_column, 'DD/MM/YYYY') as submission_date

Getting individual colors from a color map in matplotlib

I had precisely this problem, but I needed sequential plots to have highly contrasting color. I was also doing plots with a common sub-plot containing reference data, so I wanted the color sequence to be consistently repeatable.

I initially tried simply generating colors randomly, reseeding the RNG before each plot. This worked OK (commented-out in code below), but could generate nearly indistinguishable colors. I wanted highly contrasting colors, ideally sampled from a colormap containing all colors.

I could have as many as 31 data series in a single plot, so I chopped the colormap into that many steps. Then I walked the steps in an order that ensured I wouldn't return to the neighborhood of a given color very soon.

My data is in a highly irregular time series, so I wanted to see the points and the lines, with the point having the 'opposite' color of the line.

Given all the above, it was easiest to generate a dictionary with the relevant parameters for plotting the individual series, then expand it as part of the call.

Here's my code. Perhaps not pretty, but functional.

from matplotlib import cm
cmap = cm.get_cmap('gist_rainbow')  #('hsv') #('nipy_spectral')

max_colors = 31   # Constant, max mumber of series in any plot.  Ideally prime.
color_number = 0  # Variable, incremented for each series.

def restart_colors():
    global color_number
    color_number = 0
    #np.random.seed(1)

def next_color():
    global color_number
    color_number += 1
    #color = tuple(np.random.uniform(0.0, 0.5, 3))
    color = cmap( ((5 * color_number) % max_colors) / max_colors )
    return color

def plot_args():  # Invoked for each plot in a series as: '**(plot_args())'
    mkr = next_color()
    clr = (1 - mkr[0], 1 - mkr[1], 1 - mkr[2], mkr[3])  # Give line inverse of marker color
    return {
        "marker": "o",
        "color": clr,
        "mfc": mkr,
        "mec": mkr,
        "markersize": 0.5,
        "linewidth": 1,
    }

My context is JupyterLab and Pandas, so here's sample plot code:

restart_colors()  # Repeatable color sequence for every plot

fig, axs = plt.subplots(figsize=(15, 8))
plt.title("%s + T-meter"%name)

# Plot reference temperatures:
axs.set_ylabel("°C", rotation=0)
for s in ["T1", "T2", "T3", "T4"]:
    df_tmeter.plot(ax=axs, x="Timestamp", y=s, label="T-meter:%s" % s, **(plot_args()))

# Other series gets their own axis labels
ax2 = axs.twinx()
ax2.set_ylabel(units)

for c in df_uptime_sensors:
    df_uptime[df_uptime["UUID"] == c].plot(
        ax=ax2, x="Timestamp", y=units, label="%s - %s" % (units, c), **(plot_args())
    )

fig.tight_layout()
plt.show()

The resulting plot may not be the best example, but it becomes more relevant when interactively zoomed in. uptime + T-meter

Detect click outside React component

https://stackoverflow.com/a/42234988/9536897 it's not work on mobile mode.

than you can try:

  // returns true if the element or one of its parents has the class classname
  hasSomeParentTheClass(element, classname) {
    if(element.target)
    element=element.target;
    
    if (element.className&& element.className.split(" ").indexOf(classname) >= 0) return true;
    return (
      element.parentNode &&
      this.hasSomeParentTheClass(element.parentNode, classname)
    );
  }
  componentDidMount() {
    const fthis = this;

    $(window).click(function (element) {
      if (!fthis.hasSomeParentTheClass(element, "myClass"))
        fthis.setState({ pharmacyFocus: null });
    });
  }
  • On the view, gave className to your specific element.

'JSON' is undefined error in JavaScript in Internet Explorer

I had this error 2 times. Each time it was solved by changing the ajax type. Either GET to POST or POST to GET.

$.ajax({
        type:'GET', // or 'POST'
        url: "file.cfm?action=get_table&varb=" + varb
    });

How to open standard Google Map application from my application?

Sometimes if there's no any application associated with geo: protocal , you could use try-catch to get the ActivityNotFoundException to handle it.

It happens when you use some emulator like androVM which is not installed google map by default.

WARNING: Exception encountered during context initialization - cancelling refresh attempt

The important part is this:

Cannot find class [com.rakuten.points.persistence.manager.MemberPointSummaryDAOImpl] for bean with name 'MemberPointSummaryDAOImpl' defined in ServletContext resource [/WEB-INF/context/PersistenceManagerContext.xml];

due to:

nested exception is java.lang.ClassNotFoundException: com.rakuten.points.persistence.manager.MemberPointSummaryDAOImpl

According to this log, Spring could not find your MemberPointSummaryDAOImpl class.

Show current assembly instruction in GDB

You can do

display/i $pc

and every time GDB stops, it will display the disassembly of the next instruction.

GDB-7.0 also supports set disassemble-next-line on, which will disassemble the entire next line, and give you more of the disassembly context.

How to grab substring before a specified character jQuery or JavaScript

If you like it short simply use a RegExp:

var streetAddress = /[^,]*/.exec(addy)[0];

Time comparison

package javaapplication4;

import java.text.*;
import java.util.*;

/**
 *
 * @author Stefan Wendelmann
 */
public class JavaApplication4
{
    private static SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.SSS");

  /**
   * @param args the command line arguments
   */
  public static void main(String[] args) throws ParseException
  {
    SimpleDateFormat parser = new SimpleDateFormat("dd.MM.YYYY HH:mm:ss.SSS");
    Date before = parser.parse("01.10.1990 07:00:00.000");
    Date base = parser.parse("01.10.1990 08:00:00.000");
    Date after = parser.parse("01.10.1990 09:00:00.000");

    printCompare(base, base, "==");
    printCompare(base, before, "==");
    printCompare(base, before, "<");
    printCompare(base, after, "<");
    printCompare(base, after, ">");
    printCompare(base, before, ">");
    printCompare(base, before, "<=");
    printCompare(base, base, "<=");
    printCompare(base, after, "<=");
    printCompare(base, after, ">=");
    printCompare(base, base, ">=");
    printCompare(base, before, ">=");

  }

  private static void printCompare (Date a, Date b, String operator){
    System.out.println(sdf.format(b)+"\t"+operator+"\t"+sdf.format(a)+"\t"+compareTime(a, b, operator));
  }

  protected static boolean compareTime(Date a, Date b, String operator)
  {
    if (a == null)
    {
      return false;
    }
    try
    {
      //Zeit aus Datum holen
// The Magic happens here i only get the Time out of the Date Object
      SimpleDateFormat parser = new SimpleDateFormat("HH:mm:ss.SSS");
      a = parser.parse(parser.format(a));
      b = parser.parse(parser.format(b));
    }
    catch (ParseException ex)
    {
      System.err.println(ex);
    }
    switch (operator)
    {
      case "==":
        return b.compareTo(a) == 0;
      case "<":
        return b.compareTo(a) < 0;
      case ">":
        return b.compareTo(a) > 0;
      case "<=":
        return b.compareTo(a) <= 0;
      case ">=":
        return b.compareTo(a) >= 0;
      default:
        throw new IllegalArgumentException("Operator " + operator + " wird für Feldart Time nicht unterstützt!");

    }
  }

}



run:
08:00:00.000    ==  08:00:00.000    true
07:00:00.000    ==  08:00:00.000    false
07:00:00.000    <   08:00:00.000    true
09:00:00.000    <   08:00:00.000    false
09:00:00.000    >   08:00:00.000    true
07:00:00.000    >   08:00:00.000    false
07:00:00.000    <=  08:00:00.000    true
08:00:00.000    <=  08:00:00.000    true
09:00:00.000    <=  08:00:00.000    false
09:00:00.000    >=  08:00:00.000    true
08:00:00.000    >=  08:00:00.000    true
07:00:00.000    >=  08:00:00.000    false
BUILD SUCCESSFUL (total time: 0 seconds)

How do I obtain a Query Execution Plan in SQL Server?

Beside the methods described in previous answers, you can also use a free execution plan viewer and query optimization tool ApexSQL Plan (which I’ve recently bumped into).

You can install and integrate ApexSQL Plan into SQL Server Management Studio, so execution plans can be viewed from SSMS directly.

Viewing Estimated execution plans in ApexSQL Plan

  1. Click the New Query button in SSMS and paste the query text in the query text window. Right click and select the “Display Estimated Execution Plan” option from the context menu.

New Query button in SSMS

  1. The execution plan diagrams will be shown the Execution Plan tab in the results section. Next right-click the execution plan and in the context menu select the “Open in ApexSQL Plan” option.

Execution Plan

  1. The Estimated execution plan will be opened in ApexSQL Plan and it can be analyzed for query optimization.

Estimated execution plan

Viewing Actual execution plans in ApexSQL Plan

To view the Actual execution plan of a query, continue from the 2nd step mentioned previously, but now, once the Estimated plan is shown, click the “Actual” button from the main ribbon bar in ApexSQL Plan.

click the “Actual” button from the main ribbon bar

Once the “Actual” button is clicked, the Actual execution plan will be shown with detailed preview of the cost parameters along with other execution plan data.

Actual execution plan

More information about viewing execution plans can be found by following this link.

How to position background image in bottom right corner? (CSS)

Did you try something like:

body {background: url('[url to your image]') no-repeat right bottom;}

Writing to CSV with Python adds blank lines

You need to open the file in binary b mode to take care of blank lines in Python 2. This isn't required in Python 3.

So, change open('test.csv', 'w') to open('test.csv', 'wb').

How do I put a border around an Android textview?

I was just looking at a similar answer-- it's able to be done with a Stroke and the following override:

@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {

Paint strokePaint = new Paint();
strokePaint.setARGB(255, 0, 0, 0);
strokePaint.setTextAlign(Paint.Align.CENTER);
strokePaint.setTextSize(16);
strokePaint.setTypeface(Typeface.DEFAULT_BOLD);
strokePaint.setStyle(Paint.Style.STROKE);
strokePaint.setStrokeWidth(2);

Paint textPaint = new Paint();
textPaint.setARGB(255, 255, 255, 255);
textPaint.setTextAlign(Paint.Align.CENTER);
textPaint.setTextSize(16);
textPaint.setTypeface(Typeface.DEFAULT_BOLD);

canvas.drawText("Some Text", 100, 100, strokePaint);
canvas.drawText("Some Text", 100, 100, textPaint);

super.draw(canvas, mapView, shadow); 
}

how to change a selections options based on another select option selected?

as a complementary answer to @Navid_pdp11, which will enable to select the first visible item and work on document load as well. put the following below your body tag

<script>
$('#mainCat').on('change', function() {
    let selected = $(this).val();
    $("#expertCat option").each(function(){
        let element =  $(this) ;
        if (element.data("tag") != selected){
            element.removeClass('visible');
            element.addClass('hidden');
            element.hide() ;
        }else{
            element.removeClass('hidden');
            element.addClass('visible');
            element.show();
        }
    });
    let expertCat = $('#expertCat');
    expertCat.prop('selectedIndex',expertCat.find("option.visible:eq(0)").index());
}).triggerHandler('change');
</script>

Select records from today, this week, this month php mysql

Everybody seems to refer to date being a column in the table.
I dont think this is good practice. The word date might just be a keyword in some coding language (maybe Oracle) so please change the columnname date to maybe JDate.
So will the following work better:

SELECT * FROM jokes WHERE JDate >= CURRENT_DATE() ORDER BY JScore DESC;

So we have a table called Jokes with columns JScore and JDate.

Spring Data JPA findOne() change to Optional how to use this?

I always write a default method "findByIdOrError" in widely used CrudRepository repos/interfaces.

@Repository 
public interface RequestRepository extends CrudRepository<Request, Integer> {

    default Request findByIdOrError(Integer id) {
        return findById(id).orElseThrow(EntityNotFoundException::new);
    } 
}

What is Domain Driven Design?

Here is another good article that you may check out on Domain Driven Design. if your application is anything serious than college assignment. The basic premise is structure everything around your entities and have a strong domain model. Differentiate between services that provide infrastructure related things (like sending email, persisting data) and services that actually do things that are your core business requirments.

Hope that helps.

Rounding SQL DateTime to midnight

Here is the simplest thing I've found

-- Midnight floor of current date

SELECT Convert(DateTime, DATEDIFF(DAY, 0, GETDATE()))

The DATEDIFF returns the integer number of days before or since 1900-1-1, and the Convert Datetime obligingly brings it back to that date at midnight.

Since DateDiff returns an integer you can use add or subtract days to get the right offset.

SELECT Convert(DateTime, DATEDIFF(DAY, 0, GETDATE()) + @dayOffset)

This isn't rounding this is truncating...But I think that is what is being asked. (To round add one and truncate...and that's not rounding either, that the ceiling, but again most likely what you want. To really round add .5 (does that work?) and truncate.

It turns out you can add .5 to GetDate() and it works as expected.

-- Round Current time to midnight today or midnight tomorrow

SELECT Convert(DateTime, DATEDIFF(DAY, 0, GETDATE() + .5))

I did all my trials on SQL Server 2008, but I think these functions apply to 2005 as well.

How do I set up NSZombieEnabled in Xcode 4?

On In Xcode 7

?<

or select Edit Scheme from Product > Scheme Menu

select Enable Zombie Objects form the Diagnostics tab

xcode 7 zombie flag

As alternative, if you prefer .xcconfig files you can read this article https://therealbnut.wordpress.com/2012/01/01/setting-xcode-4-0-environment-variables-from-a-script/

Django: OperationalError No Such Table

I'm using Django 1.9, SQLite3 and DjangoCMS 3.2 and had the same issue. I solved it by running python manage.py makemigrations. This was followed by a prompt stating that the database contained non-null value types but did not have a default value set. It gave me two options: 1) select a one off value now or 2) exit and change the default setting in models.py. I selected the first option and gave the default value of 1. Repeated this four or five times until the prompt said it was finished. I then ran python manage.py migrate. Now it works just fine. Remember, by running python manage.py makemigrations first, a revised copy of the database is created (mine was 0004) and you can always revert back to a previous database state.

'No JUnit tests found' in Eclipse

junit4 require that test classname should be use Test as suffix.

Node.js - get raw request body using Express

// Change the way body-parser is used
const bodyParser = require('body-parser');

var rawBodySaver = function (req, res, buf, encoding) {
  if (buf && buf.length) {
    req.rawBody = buf.toString(encoding || 'utf8');
  }
}
app.use(bodyParser.json({ verify: rawBodySaver, extended: true }));




// Now we can access raw-body any where in out application as follows
request.rawBody;

Forward declaring an enum in C++

My solution to your problem would be to either:

1 - use int instead of enums: Declare your ints in an anonymous namespace in your CPP file (not in the header):

namespace
{
   const int FUNCTIONALITY_NORMAL = 0 ;
   const int FUNCTIONALITY_RESTRICTED = 1 ;
   const int FUNCTIONALITY_FOR_PROJECT_X = 2 ;
}

As your methods are private, no one will mess with the data. You could even go further to test if someone sends you an invalid data:

namespace
{
   const int FUNCTIONALITY_begin = 0 ;
   const int FUNCTIONALITY_NORMAL = 0 ;
   const int FUNCTIONALITY_RESTRICTED = 1 ;
   const int FUNCTIONALITY_FOR_PROJECT_X = 2 ;
   const int FUNCTIONALITY_end = 3 ;

   bool isFunctionalityCorrect(int i)
   {
      return (i >= FUNCTIONALITY_begin) && (i < FUNCTIONALITY_end) ;
   }
}

2 : create a full class with limited const instantiations, like done in Java. Forward declare the class, and then define it in the CPP file, and instanciate only the enum-like values. I did something like that in C++, and the result was not as satisfying as desired, as it needed some code to simulate an enum (copy construction, operator =, etc.).

3 : As proposed before, use the privately declared enum. Despite the fact an user will see its full definition, it won't be able to use it, nor use the private methods. So you'll usually be able to modify the enum and the content of the existing methods without needing recompiling of code using your class.

My guess would be either the solution 3 or 1.

Find duplicate lines in a file and count how many time each line was duplicated?

Assuming you've got access to a standard Unix shell and/or cygwin environment:

tr -s ' ' '\n' < yourfile | sort | uniq -d -c
       ^--space char

Basically: convert all space characters to linebreaks, then sort the tranlsated output and feed that to uniq and count duplicate lines.

Shortcuts in Objective-C to concatenate NSStrings

Here's a simple way, using the new array literal syntax:

NSString * s = [@[@"one ", @"two ", @"three"] componentsJoinedByString:@""];
                  ^^^^^^^ create array ^^^^^
                                               ^^^^^^^ concatenate ^^^^^

How to write one new line in Bitbucket markdown?

It's possible, as addressed in Issue #7396:

When you do want to insert a <br /> break tag using Markdown, you end a line with two or more spaces, then type return or Enter.

Batch files : How to leave the console window open

put at the end it will reopen your console

start cmd 

rejected master -> master (non-fast-forward)

NOTICE: This is never a recommended use of git. This will overwrite changes on the remote. Only do this if you know 100% that your local changes should be pushed to the remote master.

Try this: git push -f origin master

How to break a while loop from an if condition inside the while loop?

while(something.hasnext())
do something...
   if(contains something to process){
      do something...
      break;
   }
}

Just use the break statement;

For eg:this just prints "Breaking..."

while (true) {
     if (true) {
         System.out.println("Breaking...");
         break;
     }
     System.out.println("Did this print?");
}

How to add Python to Windows registry

When installing Python 3.4 the "Add python.exe to Path" came up unselected. Re-installed with this selected and problem resolved.

Polling the keyboard (detect a keypress) in python

Ok, since my attempt to post my solution in a comment failed, here's what I was trying to say. I could do exactly what I wanted from native Python (on Windows, not anywhere else though) with the following code:

import msvcrt 

def kbfunc(): 
   x = msvcrt.kbhit()
   if x: 
      ret = ord(msvcrt.getch()) 
   else: 
      ret = 0 
   return ret

What is the difference between explicit and implicit cursors in Oracle?

In PL/SQL, A cursor is a pointer to this context area. It contains all the information needed for processing the statement.

Implicit Cursors: Implicit cursors are automatically created by Oracle whenever an SQL statement is executed, when there is no explicit cursor for the statement. Programmers cannot control the implicit cursors and the information in it.

Explicit Cursors: Explicit cursors are programmer-defined cursors for gaining more control over the context area. An explicit cursor should be defined in the declaration section of the PL/SQL Block. It is created on a SELECT Statement which returns more than one row.

The syntax for creating an explicit cursor is:

CURSOR cursor_name IS select_statement; 

iTerm 2: How to set keyboard shortcuts to jump to beginning/end of line?

The old fashion emacs bindings can still work in iterm2 and os x terminal:

Preferences -> Profiles -> Keys (sub tab in profiles)

  • Set Left/Right option <kbd>?</kbd> key acts as +Esc (similar in os x terminal)

This should enable alt-f and alt-b for moving words by words. (Still ctrl-a and ctrl-e always work as usual)

If set as meta those old bindings will work while some iterm2 bindings unavailable.