Programs & Examples On #P4java

Use different Python version with virtualenv

As already mentioned in multiple answers, using virtualenv is a clean solution. However a small pitfall that everyone should be aware of is that if an alias for python is set in bash_aliases like:

python=python3.6

this alias will also be used inside the virtual environment. So in this scenario running python -V inside the virtual env will always output 3.6 regardless of what interpreter is used to create the environment:

virtualenv venv --python=pythonX.X

AltGr key not working, instead I have to use Ctrl+AltGr

I found a solution for my problem while writing my question !

Going into my remote session i tried two key combinations, and it solved the problem on my Desktop : Alt+Enter and Ctrl+Enter (i don't know which one solved the problem though)

I tried to reproduce the problem, but i couldn't... but i'm almost sure it's one of the key combinations described in the question above (since i experienced this problem several times)

So it seems the problem comes from the use of RDP (windows7 and 8)

Update 2017: Problem occurs on Windows 10 aswell.

Using the HTML5 "required" attribute for a group of checkboxes?

Hi just use a text box additional to group of check box.When clicking on any check box put values in to that text box.Make that that text box required and readonly.

How to place the ~/.composer/vendor/bin directory in your PATH?

Detailed instructions:

in your ~/.bashrc add these lines:

export PATH="$PATH:~/.composer/vendor/bin"

Then reload:

source ~/.bashrc

Check if its added correctly:

echo $PATH

/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/web/bin:~/.composer/vendor/bin

Combining Two Images with OpenCV

You can also use OpenCV's inbuilt functions cv2.hconcat and cv2.vconcat which like their names suggest are used to join images horizontally and vertically respectively.

import cv2

img1 = cv2.imread('opencv/lena.jpg')
img2 = cv2.imread('opencv/baboon.jpg')

v_img = cv2.vconcat([img1, img2])
h_img = cv2.hconcat([img1, img2])

cv2.imshow('Horizontal', h_img)
cv2.imshow('Vertical', v_img)
cv2.waitKey(0)
cv2.destroyAllWindows()

Horizontal Concatenation

Horizontal

Vertical Concatenation

Vertical

How to use SearchView in Toolbar Android

If you want to add it directly in the toolbar.

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.AppBarLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.Toolbar
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <SearchView
            android:id="@+id/searchView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:iconifiedByDefault="false"
            android:queryHint="Search"
            android:layout_centerHorizontal="true" />

    </android.support.v7.widget.Toolbar>

</android.support.design.widget.AppBarLayout>

Variables within app.config/web.config

You can use environment variables in your app.config for that scenario you describe

<configuration>
  <appSettings>
    <add key="Dir1" value="%MyBaseDir%\Dir1"/>
  </appSettings>
</configuration>

Then you can easily get the path with:

var pathFromConfig = ConfigurationManager.AppSettings["Dir1"];
var expandedPath = Environment.ExpandEnvironmentVariables(pathFromConfig);

How to install php-curl in Ubuntu 16.04

For Ubuntu 18.04 or PHP 7.2 users you can do:

apt-get install php7.2-curl

You can check your PHP version by running php -v to verify your PHP version and get the right curl version.

Show image using file_get_contents

You can do that, or you can use the readfile function, which outputs it for you:

header('Content-Type: image/x-png'); //or whatever
readfile('thefile.png');
die();

Edit: Derp, fixed obvious glaring typo.

How to change the date format from MM/DD/YYYY to YYYY-MM-DD in PL/SQL?

For military time formatting,

select TO_CHAR(SYSDATE, 'yyyy-mm-dd hh24:mm:ss') from DUAL

--2018-07-10 15:07:15

If you want your date to round DOWN to Month, Day, Hour, Minute, you can try

SELECT TO_CHAR( SYSDATE, 'yyyy-mm-dd hh24:mi:ss') "full-date" --2018-07-11 10:40:26
, TO_CHAR( TRUNC(SYSDATE, 'year'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-year"-- 2018-01-01 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'month'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-month" -- 2018-07-01 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'day'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-Sunday" -- 2018-07-08 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'dd'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-day" -- 2018-07-11 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'hh'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-hour" -- 2018-07-11 10:00:00
, TO_CHAR( TRUNC(SYSDATE, 'mi'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-minute" -- 2018-07-11 10:40:00
from DUAL

For formats literals, you can find help in https://docs.oracle.com/cd/B28359_01/server.111/b28286/functions242.htm#SQLRF52037

git pull displays "fatal: Couldn't find remote ref refs/heads/xxxx" and hangs up

I had the same issue. But in my case it was due to my branch's name. The branch's name automatically set in my GitHub repo as main instead of master.

git pull origin master (did not work).

I confirmed in GitHub if the name of the branch was actually master and found the the actual name was main. so the commands below worked for me. git pull origin main

Python in Xcode 4+?

Another way, which I've been using for awhile in XCode3:

See steps 1-15 above.

  1. Choose /bin/bash as your executable
  2. For the "Debugger" field, select "None".
  3. In the "Arguments" tab, click the "Base Expansions On" field and select the target you created earlier.
  4. Click the "+" icon under "Arguments Passed On Launch". You may have to expand that section by clicking on the triangle pointing to the right.
  5. Type in "-l". This will tell bash to use your login environment (PYTHONPATH, etc..)
  6. Do step #19 again.
  7. Type in "-c '$(SOURCE_ROOT)/.py'"
  8. Click "OK".
  9. Start coding.

The nice thing about this way is it will use the same environment to develop in that you would use to run in outside of XCode (as setup from your bash .profile).

It's also generic enough to let you develop/run any type of file, not just python.

Python JSON dump / append to .txt with each variable on new line

To avoid confusion, paraphrasing both question and answer. I am assuming that user who posted this question wanted to save dictionary type object in JSON file format but when the user used json.dump, this method dumped all its content in one line. Instead, he wanted to record each dictionary entry on a new line. To achieve this use:

with g as outfile:
  json.dump(hostDict, outfile,indent=2)

Using indent = 2 helped me to dump each dictionary entry on a new line. Thank you @agf. Rewriting this answer to avoid confusion.

What is the difference between a Shared Project and a Class Library in Visual Studio 2015?

The difference between a shared project and a class library is that the latter is compiled and the unit of reuse is the assembly.

Whereas with the former, the unit of reuse is the source code, and the shared code is incorporated into each assembly that references the shared project.

This can be useful when you want to create separate assemblies that target specific platforms but still have code that should be shared.

See also here:

The shared project reference shows up under the References node in the Solution Explorer, but the code and assets in the shared project are treated as if they were files linked into the main project.


In previous versions of Visual Studio1, you could share source code between projects by Add -> Existing Item and then choosing to Link. But this was kind of clunky and each separate source file had to be selected individually. With the move to supporting multiple disparate platforms (iOS, Android, etc), they decided to make it easier to share source between projects by adding the concept of Shared Projects.


1 This question and my answer (up until now) suggest that Shared Projects was a new feature in Visual Studio 2015. In fact, they made their debut in Visual Studio 2013 Update 2

figure of imshow() is too small

Update 2020

as requested by @baxxx, here is an update because random.rand is deprecated meanwhile.

This works with matplotlip 3.2.1:

from matplotlib import pyplot as plt
import random
import numpy as np

random = np.random.random ([8,90])

plt.figure(figsize = (20,2))
plt.imshow(random, interpolation='nearest')

This plots:

enter image description here

To change the random number, you can experiment with np.random.normal(0,1,(8,90)) (here mean = 0, standard deviation = 1).

PHP multiline string with PHP

The internal set of single quotes in your code is killing the string. Whenever you hit a single quote it ends the string and continues processing. You'll want something like:

$thisstring = 'this string is long \' in needs escaped single quotes or nothing will run';

Get the difference between two dates both In Months and days in sql

Updated for correctness. Originally answered by @jen.

with DATES as (
   select TO_DATE('20120101', 'YYYYMMDD') as Date1,
          TO_DATE('20120325', 'YYYYMMDD') as Date2
   from DUAL union all
   select TO_DATE('20120101', 'YYYYMMDD') as Date1,
          TO_DATE('20130101', 'YYYYMMDD') as Date2
   from DUAL union all
   select TO_DATE('20120101', 'YYYYMMDD') as Date1,
          TO_DATE('20120101', 'YYYYMMDD') as Date2
   from DUAL union all
   select TO_DATE('20130228', 'YYYYMMDD') as Date1,
          TO_DATE('20130301', 'YYYYMMDD') as Date2
   from DUAL union all
   select TO_DATE('20130228', 'YYYYMMDD') as Date1,
          TO_DATE('20130401', 'YYYYMMDD') as Date2
   from DUAL
), MONTHS_BTW as (
   select Date1, Date2,
          MONTHS_BETWEEN(Date2, Date1) as NumOfMonths
   from DATES
)
select TO_CHAR(Date1, 'MON DD YYYY') as Date_1,
       TO_CHAR(Date2, 'MON DD YYYY') as Date_2,
       NumOfMonths as Num_Of_Months,
       TRUNC(NumOfMonths) as "Month(s)",
       ADD_MONTHS(Date2, - TRUNC(NumOfMonths)) - Date1 as "Day(s)"
from MONTHS_BTW;

SQLFiddle Demo :

    +--------------+--------------+-----------------+-----------+--------+
    |   DATE_1     |   DATE_2     | NUM_OF_MONTHS   | MONTH(S)  | DAY(S) |
    +--------------+--------------+-----------------+-----------+--------+
    | JAN 01 2012  | MAR 25 2012  | 2.774193548387  |        2  |     24 |
    | JAN 01 2012  | JAN 01 2013  | 12              |       12  |      0 |
    | JAN 01 2012  | JAN 01 2012  | 0               |        0  |      0 |
    | FEB 28 2013  | MAR 01 2013  | 0.129032258065  |        0  |      1 |
    | FEB 28 2013  | APR 01 2013  | 1.129032258065  |        1  |      1 |
    +--------------+--------------+-----------------+-----------+--------+

Notice, how for the last two dates, Oracle reports the decimal part of months (which gives days) incorrectly. 0.1290 corresponds to exactly 4 days with Oracle considering 31 days in a month (for both March and April).

node and Error: EMFILE, too many open files

For when graceful-fs doesn't work... or you just want to understand where the leak is coming from. Follow this process.

(e.g. graceful-fs isn't gonna fix your wagon if your issue is with sockets.)

From My Blog Article: http://www.blakerobertson.com/devlog/2014/1/11/how-to-determine-whats-causing-error-connect-emfile-nodejs.html

How To Isolate

This command will output the number of open handles for nodejs processes:

lsof -i -n -P | grep nodejs
COMMAND     PID    USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
...
nodejs    12211    root 1012u  IPv4 151317015      0t0  TCP 10.101.42.209:40371->54.236.3.170:80 (ESTABLISHED)
nodejs    12211    root 1013u  IPv4 151279902      0t0  TCP 10.101.42.209:43656->54.236.3.172:80 (ESTABLISHED)
nodejs    12211    root 1014u  IPv4 151317016      0t0  TCP 10.101.42.209:34450->54.236.3.168:80 (ESTABLISHED)
nodejs    12211    root 1015u  IPv4 151289728      0t0  TCP 10.101.42.209:52691->54.236.3.173:80 (ESTABLISHED)
nodejs    12211    root 1016u  IPv4 151305607      0t0  TCP 10.101.42.209:47707->54.236.3.172:80 (ESTABLISHED)
nodejs    12211    root 1017u  IPv4 151289730      0t0  TCP 10.101.42.209:45423->54.236.3.171:80 (ESTABLISHED)
nodejs    12211    root 1018u  IPv4 151289731      0t0  TCP 10.101.42.209:36090->54.236.3.170:80 (ESTABLISHED)
nodejs    12211    root 1019u  IPv4 151314874      0t0  TCP 10.101.42.209:49176->54.236.3.172:80 (ESTABLISHED)
nodejs    12211    root 1020u  IPv4 151289768      0t0  TCP 10.101.42.209:45427->54.236.3.171:80 (ESTABLISHED)
nodejs    12211    root 1021u  IPv4 151289769      0t0  TCP 10.101.42.209:36094->54.236.3.170:80 (ESTABLISHED)
nodejs    12211    root 1022u  IPv4 151279903      0t0  TCP 10.101.42.209:43836->54.236.3.171:80 (ESTABLISHED)
nodejs    12211    root 1023u  IPv4 151281403      0t0  TCP 10.101.42.209:43930->54.236.3.172:80 (ESTABLISHED)
....

Notice the: 1023u (last line) - that's the 1024th file handle which is the default maximum.

Now, Look at the last column. That indicates which resource is open. You'll probably see a number of lines all with the same resource name. Hopefully, that now tells you where to look in your code for the leak.

If you don't know multiple node processes, first lookup which process has pid 12211. That'll tell you the process.

In my case above, I noticed that there were a bunch of very similar IP Addresses. They were all 54.236.3.### By doing ip address lookups, was able to determine in my case it was pubnub related.

Command Reference

Use this syntax to determine how many open handles a process has open...

To get a count of open files for a certain pid

I used this command to test the number of files that were opened after doing various events in my app.

lsof -i -n -P | grep "8465" | wc -l
# lsof -i -n -P | grep "nodejs.*8465" | wc -l
28
# lsof -i -n -P | grep "nodejs.*8465" | wc -l
31
# lsof -i -n -P | grep "nodejs.*8465" | wc -l
34

What is your process limit?

ulimit -a

The line you want will look like this:

open files                      (-n) 1024

Permanently change the limit:

  • tested on Ubuntu 14.04, nodejs v. 7.9

In case you are expecting to open many connections (websockets is a good example), you can permanently increase the limit:

  • file: /etc/pam.d/common-session (add to the end)

      session required pam_limits.so
    
  • file: /etc/security/limits.conf (add to the end, or edit if already exists)

      root soft  nofile 40000
      root hard  nofile 100000
    
  • restart your nodejs and logout/login from ssh.

  • this may not work for older NodeJS you'll need to restart server

  • use instead of if your node runs with different uid.

How can I manually generate a .pyc file from a .py file

There is two way to do this

  1. Command line
  2. Using python program

If you are using command line use python -m compileall <argument> to compile python code to python binary code. Ex: python -m compileall -x ./*

Or, You can use this code to compile your library into byte-code.

import compileall
import os

lib_path = "your_lib_path"
build_path = "your-dest_path"

compileall.compile_dir(lib_path, force=True, legacy=True)

def moveToNewLocation(cu_path):
    for file in os.listdir(cu_path):
        if os.path.isdir(os.path.join(cu_path, file)):
            compile(os.path.join(cu_path, file))
        elif file.endswith(".pyc"):
            dest = os.path.join(build_path, cu_path ,file)
            os.makedirs(os.path.dirname(dest), exist_ok=True)
            os.rename(os.path.join(cu_path, file), dest)

moveToNewLocation(lib_path)

look at ? docs.python.org for detailed documentation

ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type already has the same primary key value

In my case , I had wrote really two times an entity of same type . So I delete it and all things work correctly

How to compare only date in moment.js

The docs are pretty clear that you pass in a second parameter to specify granularity.

If you want to limit the granularity to a unit other than milliseconds, pass the units as the second parameter.

moment('2010-10-20').isAfter('2010-01-01', 'year'); // false
moment('2010-10-20').isAfter('2009-12-31', 'year'); // true

As the second parameter determines the precision, and not just a single value to check, using day will check for year, month and day.

For your case you would pass 'day' as the second parameter.

Convert MySql DateTime stamp into JavaScript's Date format

First you can give JavaScript's Date object (class) the new method 'fromYMD()' for converting MySQL's YMD date format into JavaScript format by splitting YMD format into components and using these date components:

Date.prototype.fromYMD=function(ymd)
{
  var t=ymd.split(/[- :]/); //split into components
  return new Date(t[0],t[1]-1,t[2],t[3]||0,t[4]||0,t[5]||0);
};

Now you can define your own object (funcion in JavaScript world):

function DateFromYMD(ymd)
{
  return (new Date()).fromYMD(ymd);
}

and now you can simply create date from MySQL date format;

var d=new DateFromYMD('2016-07-24');

delete map[key] in go?

Use make (chan int) instead of nil. The first value has to be the same type that your map holds.

package main

import "fmt"

func main() {

    var sessions = map[string] chan int{}
    sessions["somekey"] = make(chan int)

    fmt.Printf ("%d\n", len(sessions)) // 1

    // Remove somekey's value from sessions
    delete(sessions, "somekey")

    fmt.Printf ("%d\n", len(sessions)) // 0
}

UPDATE: Corrected my answer.

How to get rid of punctuation using NLTK tokenizer?

Below code will remove all punctuation marks as well as non alphabetic characters. Copied from their book.

http://www.nltk.org/book/ch01.html

import nltk

s = "I can't do this now, because I'm so tired.  Please give me some time. @ sd  4 232"

words = nltk.word_tokenize(s)

words=[word.lower() for word in words if word.isalpha()]

print(words)

output

['i', 'ca', 'do', 'this', 'now', 'because', 'i', 'so', 'tired', 'please', 'give', 'me', 'some', 'time', 'sd']

How do I sort a table in Excel if it has cell references in it?

I needed to sort cells with references, and really needed to avoid pasting Values to work with.. The "Pivot Table" did the trick.

  1. Prepare your tables with references.
  2. Select the table (with references) and insert Pivot Table
  3. In the pivot table, select required filters to make the Pivot table look as your original Table (if needed).
  4. Sort / filter data further as required.

Just be sure to right click on Pivot table and hit "refresh" each time you change some generic data (used in your tables).

Hope it will help. Andrei

@Nullable annotation usage

Different tools may interpret the meaning of @Nullable differently. For example, the Checker Framework and FindBugs handle @Nullable differently.

Displaying a Table in Django from Database

$ pip install django-tables2

settings.py

INSTALLED_APPS , 'django_tables2'
TEMPLATES.OPTIONS.context-processors , 'django.template.context_processors.request'

models.py

class hotel(models.Model):
     name = models.CharField(max_length=20)

views.py

from django.shortcuts import render

def people(request):
    istekler = hotel.objects.all()
    return render(request, 'list.html', locals())

list.html

{# yonetim/templates/list.html #}
{% load render_table from django_tables2 %}
{% load static %}
<!doctype html>
<html>
    <head>
        <link rel="stylesheet" href="{% static 
'ticket/static/css/screen.css' %}" />
    </head>
    <body>
        {% render_table istekler %}
    </body>
</html>

How to close <img> tag properly?

Both the right answer. HTML5 follows strict rules and in HTML5 we can close all the tags. So, it depends on you to use HTML5 or HTML and follow an appropriate answer.

<img src='stackoverflow.png'>
<img src='stackoverflow.png' />

The second property is more appropriate.

No module named Image

You are missing PIL (Python Image Library and Imaging package). To install PIL I used

 pip install pillow

For my machine running Mac OSX 10.6.8, I downloaded Imaging package and installed it from source. http://effbot.org/downloads/Imaging-1.1.6.tar.gz and cd into Download directory. Then run these:

    $ gunzip Imaging-1.1.6.tar.gz
    $ tar xvf Imaging-1.1.6.tar
    $ cd Imaging-1.1.6
    $ python setup.py install

Or if you have PIP installed in your Mac

 pip install http://effbot.org/downloads/Imaging-1.1.6.tar.gz

then you can use:

from PIL import Image

in your python code.

Google Maps API v3 adding an InfoWindow to each marker

for Earth plugin APIs, create the balloon outside your loop and pass your counter to the function to get unique contents for each placemark!

function createBalloon(placemark, i, event) {
            var p = placemark;
            var j = i;
            google.earth.addEventListener(p, 'click', function (event) {
                    // prevent the default balloon from popping up
                    event.preventDefault();
                    var balloon = ge.createHtmlStringBalloon('');
                    balloon.setFeature(event.getTarget());

                    balloon.setContentString('iframePath#' + j);

                    ge.setBalloon(balloon);
            });
        }

Given a DateTime object, how do I get an ISO 8601 date in string format?

System.DateTime.UtcNow.ToString("o")

=>

val it : string = "2013-10-13T13:03:50.2950037Z"

java.sql.SQLException Parameter index out of range (1 > number of parameters, which is 0)

You will get this error when you call any of the setXxx() methods on PreparedStatement, while the SQL query string does not have any placeholders ? for this.

For example this is wrong:

String sql = "INSERT INTO tablename (col1, col2, col3) VALUES (val1, val2, val3)";
// ...

preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, val1); // Fail.
preparedStatement.setString(2, val2);
preparedStatement.setString(3, val3);

You need to fix the SQL query string accordingly to specify the placeholders.

String sql = "INSERT INTO tablename (col1, col2, col3) VALUES (?, ?, ?)";
// ...

preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, val1);
preparedStatement.setString(2, val2);
preparedStatement.setString(3, val3);

Note the parameter index starts with 1 and that you do not need to quote those placeholders like so:

String sql = "INSERT INTO tablename (col1, col2, col3) VALUES ('?', '?', '?')";

Otherwise you will still get the same exception, because the SQL parser will then interpret them as the actual string values and thus can't find the placeholders anymore.

See also:

Pass Multiple Parameters to jQuery ajax call

Don't use string concatenation to pass parameters, just use a data hash:

$.ajax({
    type: 'POST',
    url: 'popup.aspx/GetJewellerAssets',
    contentType: 'application/json; charset=utf-8',
    data: { jewellerId: filter, locale: 'en-US' },
    dataType: 'json',
    success: AjaxSucceeded,
    error: AjaxFailed
});

UPDATE:

As suggested by @Alex in the comments section, an ASP.NET PageMethod expects parameters to be JSON encoded in the request, so JSON.stringify should be applied on the data hash:

$.ajax({
    type: 'POST',
    url: 'popup.aspx/GetJewellerAssets',
    contentType: 'application/json; charset=utf-8',
    data: JSON.stringify({ jewellerId: filter, locale: 'en-US' }),
    dataType: 'json',
    success: AjaxSucceeded,
    error: AjaxFailed
});

ImageMagick security policy 'PDF' blocking conversion

Well, I added

  <policy domain="coder" rights="read | write" pattern="PDF" />

just before </policymap> in /etc/ImageMagick-7/policy.xml and that makes it work again, but not sure about the security implications of that.

Hibernate vs JPA vs JDO - pros and cons of each?

I am using JPA (OpenJPA implementation from Apache which is based on the KODO JDO codebase which is 5+ years old and extremely fast/reliable). IMHO anyone who tells you to bypass the specs is giving you bad advice. I put the time in and was definitely rewarded. With either JDO or JPA you can change vendors with minimal changes (JPA has orm mapping so we are talking less than a day to possibly change vendors). If you have 100+ tables like I do this is huge. Plus you get built0in caching with cluster-wise cache evictions and its all good. SQL/Jdbc is fine for high performance queries but transparent persistence is far superior for writing your algorithms and data input routines. I only have about 16 SQL queries in my whole system (50k+ lines of code).

"replace" function examples

Be aware that the third parameter (value) in the examples given above: the value is a constant (e.g. 'Z' or c(20,30)).

Defining the third parameter using values from the data frame itself can lead to confusion.

E.g. with a simple data frame such as this (using dplyr::data_frame):

tmp <- data_frame(a=1:10, b=sample(LETTERS[24:26], 10, replace=T))

This will create somthing like this:

       a     b
   (int) (chr)
1      1     X
2      2     Y
3      3     Y
4      4     X
5      5     Z

..etc

Now suppose you want wanted to do, was to multiply the values in column 'a' by 2, but only where column 'b' is "X". My immediate thought would be something like this:

with(tmp, replace(a, b=="X", a*2))

That will not provide the desired outcome, however. The a*2 will defined as a fixed vector rather than a reference to the 'a' column. The vector 'a*2' will thus be

[1]  2  4  6  8 10 12 14 16 18 20

at the start of the 'replace' operation. Thus, the first row where 'b' equals "X", the value in 'a' will be placed by 2. The second time, it will be replaced by 4, etc ... it will not be replaced by two-times-the-value-of-a in that particular row.

Drag and drop menuitems

jQuery UI draggable and droppable are the two plugins I would use to achieve this effect. As for the insertion marker, I would investigate modifying the div (or container) element that was about to have content dropped into it. It should be possible to modify the border in some way or add a JavaScript/jQuery listener that listens for the hover (element about to be dropped) event and modifies the border or adds an image of the insertion marker in the right place.

When should I create a destructor?

Destructors provide an implicit way of freeing unmanaged resources encapsulated in your class, they get called when the GC gets around to it and they implicitly call the Finalize method of the base class. If you're using a lot of unmanaged resources it is better to provide an explicit way of freeing those resources via the IDisposable interface. See the C# programming guide: http://msdn.microsoft.com/en-us/library/66x5fx1b.aspx

Select multiple columns from a table, but group by one

I just wanted to add a more effective and generic way to solve this kind of problems. The main idea is about working with sub queries.

do your group by and join the same table on the ID of the table.

your case is more specific since your productId is not unique so there is 2 ways to solve this.

I will begin by the more specific solution: Since your productId is not unique we will need an extra step which is to select DISCTINCT product ids after grouping and doing the sub query like following:

WITH CTE_TEST AS (SELECT productId, SUM(OrderQuantity) Total
                    FROM OrderDetails
                    GROUP BY productId)
SELECT DISTINCT(OrderDetails.ProductID), OrderDetails.ProductName, CTE_TEST.Total
FROM OrderDetails 
INNER JOIN CTE_TEST ON CTE_TEST.ProductID = OrderDetails.ProductID

this returns exactly what is expected

 ProductID     ProductName         Total
    1001          abc               12    
    1002          abc               23
    2002          xyz               8
    3004          ytp               15
    4001          aze               19

But there a cleaner way to do this. I guess that ProductId is a foreign key to products table and i guess that there should be and OrderId primary key (unique) in this table.

in this case there are few steps to do to include extra columns while grouping on only one. It will be the same solution as following

Let's take this t_Value table for example:

enter image description here

If i want to group by description and also display all columns.

All i have to do is:

  1. create WITH CTE_Name subquery with your GroupBy column and COUNT condition
  2. select all(or whatever you want to display) from value table and the total from the CTE
  3. INNER JOIN with CTE on the ID(primary key or unique constraint) column

and that's it!

Here is the query

WITH CTE_TEST AS (SELECT Description, MAX(Id) specID, COUNT(Description) quantity 
                    FROM sch_dta.t_value
                    GROUP BY Description)
SELECT sch_dta.t_Value.*, CTE_TEST.quantity 
FROM sch_dta.t_Value 
INNER JOIN CTE_TEST ON CTE_TEST.specID = sch_dta.t_Value.Id

And here is the result:

enter image description here

tmux status bar configuration

Do C-b, :show which will show you all your current settings. /green, nnn will find you which properties have been set to green, the default. Do C-b, :set window-status-bg cyan and the bottom bar should change colour.

List available colours for tmux

You can tell more easily by the titles and the colours as they're actually set in your live session :show, than by searching through the man page, in my opinion. It is a very well-written man page when you have the time though.

If you don't like one of your changes and you can't remember how it was originally set, you can open do a new tmux session. To change settings for good edit ~/.tmux.conf with a line like set window-status-bg -g cyan. Here's mine: https://gist.github.com/9083598

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

Like @sanchit proposed middleware is a nice solution if you are already defining your axios instance globally.

You can create a middleware like:

function createAxiosAuthMiddleware() {
  return ({ getState }) => next => (action) => {
    const { token } = getState().authentication;
    global.axios.defaults.headers.common.Authorization = token ? `Bearer ${token}` : null;

    return next(action);
  };
}

const axiosAuth = createAxiosAuthMiddleware();

export default axiosAuth;

And use it like this:

import { createStore, applyMiddleware } from 'redux';
const store = createStore(reducer, applyMiddleware(axiosAuth))

It will set the token on every action but you could only listen for actions that change the token for example.

HTTP Error 404 when running Tomcat from Eclipse

I had this or a similar problem after installing Tomcat.

The other answers didn't quite work, but got me on the right path. I answered this at https://stackoverflow.com/a/20762179/3128838 after discovering a YouTube video showing the exact problem I was having.

How to stretch a fixed number of horizontal navigation items evenly and fully across a specified container

This one really works. Also has the benefit that you can use media queries to easily turn off the horizontal style — for instance if you want to stack them vertically when on mobile phone.

HTML

<ul id="nav">
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
    <li><a href="#">Link</a></li>
</ul>

CSS

?
#nav {
    display: table;
    height: 87px;
    width: 100%;
}

#nav li {
    display: table-cell;
    height: 87px;
    width: 16.666666667%;  /* (100 / numItems)% */
    line-height: 87px;
    text-align: center;
    background: #ddd;
    border-right: 1px solid #fff;
    white-space: nowrap;
}?

@media (max-width: 767px) {
    #nav li {
        display: block;
        width: 100%;
    }
}

http://jsfiddle.net/timshutes/eCPSh/416/

Align labels in form next to input

You can also try using flex-box

<head><style>
body {
    color:white;
    font-family:arial;
    font-size:1.2em;
}
form {
    margin:0 auto;
    padding:20px;
    background:#444;
}
.input-group {
    margin-top:10px;
    width:60%;
    display:flex;
    justify-content:space-between;
    flex-wrap:wrap;
}
label, input {
    flex-basis:100px;
}
</style></head>
<body>

<form>
    <div class="wrapper">
        <div class="input-group">
            <label for="user_name">name:</label>
            <input type="text" id="user_name">
        </div>
        <div class="input-group">
            <label for="user_pass">Password:</label>
            <input type="password" id="user_pass">
        </div>
    </div>
</form>

</body>
</html>

How to compile Tensorflow with SSE4.2 and AVX instructions?

2.0 COMPATIBLE SOLUTION:

Execute the below commands in Terminal (Linux/MacOS) or in Command Prompt (Windows) to install Tensorflow 2.0 using Bazel:

git clone https://github.com/tensorflow/tensorflow.git
cd tensorflow

#The repo defaults to the master development branch. You can also checkout a release branch to build:
git checkout r2.0

#Configure the Build => Use the Below line for Windows Machine
python ./configure.py 

#Configure the Build => Use the Below line for Linux/MacOS Machine
./configure
#This script prompts you for the location of TensorFlow dependencies and asks for additional build configuration options. 

#Build Tensorflow package

#CPU support
bazel build --config=opt //tensorflow/tools/pip_package:build_pip_package 

#GPU support
bazel build --config=opt --config=cuda --define=no_tensorflow_py_deps=true //tensorflow/tools/pip_package:build_pip_package

How to print the ld(linker) search path

The most compatible command I've found for gcc and clang on Linux (thanks to armando.sano):

$ gcc -m64 -Xlinker --verbose  2>/dev/null | grep SEARCH | sed 's/SEARCH_DIR("=\?\([^"]\+\)"); */\1\n/g'  | grep -vE '^$'

if you give -m32, it will output the correct library directories.

Examples on my machine:

for g++ -m64:

/usr/x86_64-linux-gnu/lib64
/usr/i686-linux-gnu/lib64
/usr/local/lib/x86_64-linux-gnu
/usr/local/lib64
/lib/x86_64-linux-gnu
/lib64
/usr/lib/x86_64-linux-gnu
/usr/lib64
/usr/local/lib
/lib
/usr/lib

for g++ -m32:

/usr/i686-linux-gnu/lib32
/usr/local/lib32
/lib32
/usr/lib32
/usr/local/lib/i386-linux-gnu
/usr/local/lib
/lib/i386-linux-gnu
/lib
/usr/lib/i386-linux-gnu
/usr/lib

get url content PHP

Use cURL,

Check if you have it via phpinfo();

And for the code:

function getHtml($url, $post = null) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    if(!empty($post)) {
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
    } 
    $result = curl_exec($ch);
    curl_close($ch);
    return $result;
}

Has anyone gotten HTML emails working with Twitter Bootstrap?

Emails require tables in order to work properly.

Inky (by foundation for emails) is a templating language that converts simple HTML tags into the complex table HTML required for emails.

Example

<html>

<head></head>

<body>
  <table align="center" class="container">
    <tbody>
      <tr>
        <td>
          <table class="row">
            <tbody>
              <tr>
                <th class="small-12 large-12 columns first last">
                  <table>
                    <tbody>
                      <tr>
                        <th>Put content in me!</th>
                        <th class="expander"></th>
                      </tr>
                    </tbody>
                  </table>
                </th>
              </tr>
            </tbody>
          </table>&zwj;
        </td>
      </tr>
    </tbody>
  </table>
</body>

</html>

Will produce this:

enter image description here

String parsing in Java with delimiter tab "\t" using split

Try this:

String[] columnDetail = column.split("\t", -1);

Read the Javadoc on String.split(java.lang.String, int) for an explanation about the limit parameter of split function:

split

public String[] split(String regex, int limit)
Splits this string around matches of the given regular expression.
The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

The string "boo:and:foo", for example, yields the following results with these parameters:

Regex   Limit   Result
:   2   { "boo", "and:foo" }
:   5   { "boo", "and", "foo" }
:   -2  { "boo", "and", "foo" }
o   5   { "b", "", ":and:f", "", "" }
o   -2  { "b", "", ":and:f", "", "" }
o   0   { "b", "", ":and:f" }

When the last few fields (I guest that's your situation) are missing, you will get the column like this:

field1\tfield2\tfield3\t\t

If no limit is set to split(), the limit is 0, which will lead to that "trailing empty strings will be discarded". So you can just get just 3 fields, {"field1", "field2", "field3"}.

When limit is set to -1, a non-positive value, trailing empty strings will not be discarded. So you can get 5 fields with the last two being empty string, {"field1", "field2", "field3", "", ""}.

How to force a WPF binding to refresh?

MultiBinding friendly version...

private void ComboBox_Loaded(object sender, RoutedEventArgs e)
{
    BindingOperations.GetBindingExpressionBase((ComboBox)sender, ComboBox.ItemsSourceProperty).UpdateTarget();
}

Getting java.net.SocketTimeoutException: Connection timed out in android

I faced the same problem when connecting to EC2, the issue was with Security Group, I solved by adding the allowed IPs at port 5432

printf a variable in C

Your printf needs a format string:

printf("%d\n", x);

This reference page gives details on how to use printf and related functions.

How to access the correct `this` inside a callback?

I was facing problem with Ngx line chart xAxisTickFormatting function which was called from HTML like this: [xAxisTickFormatting]="xFormat". I was unable to access my component's variable from the function declared. This solution helped me to resolve the issue to find the correct this. Hope this helps the Ngx line chart, users.

instead of using the function like this:

xFormat (value): string {
  return value.toString() + this.oneComponentVariable; //gives wrong result 
}

Use this:

 xFormat = (value) => {
   // console.log(this);
   // now you have access to your component variables
   return value + this.oneComponentVariable
 }

How do you convert an entire directory with ffmpeg?

Getting a bit like code golf here, but since nearly all the answers so far are bash (barring one lonely cmd one), here's a windows cross-platform command that uses powershell (because awesome):

ls *.avi|%{ ffmpeg -i $_ <ffmpeg options here> $_.name.replace($_.extension, ".mp4")}

You can change *.avi to whatever matches your source footage.

Reading Excel files from C#

While you did specifically ask for .xls, implying the older file formats, for the OpenXML formats (e.g. xlsx) I highly recommend the OpenXML SDK (http://msdn.microsoft.com/en-us/library/bb448854.aspx)

Extract a page from a pdf as a jpeg

Here is a solution which requires no additional libraries and is very fast. This was found from: https://nedbatchelder.com/blog/200712/extracting_jpgs_from_pdfs.html# I have added the code in a function to make it more convenient.

def convert(filepath):
    with open(filepath, "rb") as file:
        pdf = file.read()

    startmark = b"\xff\xd8"
    startfix = 0
    endmark = b"\xff\xd9"
    endfix = 2
    i = 0

    njpg = 0
    while True:
        istream = pdf.find(b"stream", i)
        if istream < 0:
            break
        istart = pdf.find(startmark, istream, istream + 20)
        if istart < 0:
            i = istream + 20
            continue
        iend = pdf.find(b"endstream", istart)
        if iend < 0:
            raise Exception("Didn't find end of stream!")
        iend = pdf.find(endmark, iend - 20)
        if iend < 0:
            raise Exception("Didn't find end of JPG!")

        istart += startfix
        iend += endfix
        jpg = pdf[istart:iend]
        newfile = "{}jpg".format(filepath[:-3])
        with open(newfile, "wb") as jpgfile:
            jpgfile.write(jpg)

        njpg += 1
        i = iend

        return newfile

Call convert with the pdf path as the argument and the function will create a .jpg file in the same directory

Saving a select count(*) value to an integer (SQL Server)

select @myInt = COUNT(*) from myTable

Rails where condition using NOT NIL

It's not a bug in ARel, it's a bug in your logic.

What you want here is:

Foo.includes(:bar).where(Bar.arel_table[:id].not_eq(nil))

How to ignore ansible SSH authenticity checking?

The most problems appear when you want to add new host to dynamic inventory (via add_host module) in playbook. I don't want to disable fingerprint host checking permanently so solutions like disabling it in a global config file are not ok for me. Exporting var like ANSIBLE_HOST_KEY_CHECKING before running playbook is another thing to do before running that need to be remembered.

It's better to add local config file in the same dir where playbook is. Create file named ansible.cfg and paste following text:

[defaults]
host_key_checking = False

No need to remember to add something in env vars or add to ansible-playbook options. It's easy to put this file to ansible git repo.

compare two list and return not matching items using linq

Well, you already have good answers, but they're most Lambda. A more LINQ approach would be like

var NotSentMessages =
                from msg in MsgList
                where !SentList.Any(x => x.MsgID == msg.MsgID)
                select msg;

What is the Python equivalent of Matlab's tic and toc functions?

Usually, IPython's %time, %timeit, %prun and %lprun (if one has line_profiler installed) satisfy my profiling needs quite well. However, a use case for tic-toc-like functionality arose when I tried to profile calculations that were interactively driven, i.e., by the user's mouse motion in a GUI. I felt like spamming tics and tocs in the sources while testing interactively would be the fastest way to reveal the bottlenecks. I went with Eli Bendersky's Timer class, but wasn't fully happy, since it required me to change the indentation of my code, which can be inconvenient in some editors and confuses the version control system. Moreover, there may be the need to measure the time between points in different functions, which wouldn't work with the with statement. After trying lots of Python cleverness, here is the simple solution that I found worked best:

from time import time
_tstart_stack = []

def tic():
    _tstart_stack.append(time())

def toc(fmt="Elapsed: %s s"):
    print fmt % (time() - _tstart_stack.pop())

Since this works by pushing the starting times on a stack, it will work correctly for multiple levels of tics and tocs. It also allows one to change the format string of the toc statement to display additional information, which I liked about Eli's Timer class.

For some reason I got concerned with the overhead of a pure Python implementation, so I tested a C extension module as well:

#include <Python.h>
#include <mach/mach_time.h>
#define MAXDEPTH 100

uint64_t start[MAXDEPTH];
int lvl=0;

static PyObject* tic(PyObject *self, PyObject *args) {
    start[lvl++] = mach_absolute_time();
    Py_RETURN_NONE;
}

static PyObject* toc(PyObject *self, PyObject *args) {
return PyFloat_FromDouble(
        (double)(mach_absolute_time() - start[--lvl]) / 1000000000L);
}

static PyObject* res(PyObject *self, PyObject *args) {
    return tic(NULL, NULL), toc(NULL, NULL);
}

static PyMethodDef methods[] = {
    {"tic", tic, METH_NOARGS, "Start timer"},
    {"toc", toc, METH_NOARGS, "Stop timer"},
    {"res", res, METH_NOARGS, "Test timer resolution"},
    {NULL, NULL, 0, NULL}
};

PyMODINIT_FUNC
inittictoc(void) {
    Py_InitModule("tictoc", methods);
}

This is for MacOSX, and I have omitted code to check if lvl is out of bounds for brevity. While tictoc.res() yields a resolution of about 50 nanoseconds on my system, I found that the jitter of measuring any Python statement is easily in the microsecond range (and much more when used from IPython). At this point, the overhead of the Python implementation becomes negligible, so that it can be used with the same confidence as the C implementation.

I found that the usefulness of the tic-toc-approach is practically limited to code blocks that take more than 10 microseconds to execute. Below that, averaging strategies like in timeit are required to get a faithful measurement.

How do I plot list of tuples in Python?

In matplotlib it would be:

import matplotlib.pyplot as plt

data =  [(0, 6.0705199999997801e-08), (1, 2.1015700100300739e-08),
 (2, 7.6280656623374823e-09), (3, 5.7348209304555086e-09),
 (4, 3.6812203579604238e-09), (5, 4.1572516753310418e-09)]

x_val = [x[0] for x in data]
y_val = [x[1] for x in data]

print x_val
plt.plot(x_val,y_val)
plt.plot(x_val,y_val,'or')
plt.show()

which would produce:

enter image description here

Get model's fields in Django

This is something that is done by Django itself when building a form from a model. It is using the _meta attribute, but as Bernhard noted, it uses both _meta.fields and _meta.many_to_many. Looking at django.forms.models.fields_for_model, this is how you could do it:

opts = model._meta
for f in sorted(opts.fields + opts.many_to_many):
    print '%s: %s' % (f.name, f)

Submit form using AJAX and jQuery

There is a nice form plugin that allows you to send an HTML form asynchroniously.

$(document).ready(function() { 
    $('#myForm1').ajaxForm(); 
});

or

$("select").change(function(){
    $('#myForm1').ajaxSubmit();
});

to submit the form immediately

Limiting the number of characters in a string, and chopping off the rest

If you just want a maximum length, use StringUtils.left! No if or ternary ?: needed.

int maxLength = 5;
StringUtils.left(string, maxLength);

Output:

      null -> null
        "" -> ""
       "a" -> "a"
"abcd1234" -> "abcd1"

Left Documentation

scrollTop animation without jquery

HTML:

<button onclick="scrollToTop(1000);"></button>

1# JavaScript (linear):

function scrollToTop (duration) {
    // cancel if already on top
    if (document.scrollingElement.scrollTop === 0) return;

    const totalScrollDistance = document.scrollingElement.scrollTop;
    let scrollY = totalScrollDistance, oldTimestamp = null;

    function step (newTimestamp) {
        if (oldTimestamp !== null) {
            // if duration is 0 scrollY will be -Infinity
            scrollY -= totalScrollDistance * (newTimestamp - oldTimestamp) / duration;
            if (scrollY <= 0) return document.scrollingElement.scrollTop = 0;
            document.scrollingElement.scrollTop = scrollY;
        }
        oldTimestamp = newTimestamp;
        window.requestAnimationFrame(step);
    }
    window.requestAnimationFrame(step);
}

2# JavaScript (ease in and out):

function scrollToTop (duration) {
    // cancel if already on top
    if (document.scrollingElement.scrollTop === 0) return;

    const cosParameter = document.scrollingElement.scrollTop / 2;
    let scrollCount = 0, oldTimestamp = null;

    function step (newTimestamp) {
        if (oldTimestamp !== null) {
            // if duration is 0 scrollCount will be Infinity
            scrollCount += Math.PI * (newTimestamp - oldTimestamp) / duration;
            if (scrollCount >= Math.PI) return document.scrollingElement.scrollTop = 0;
            document.scrollingElement.scrollTop = cosParameter + cosParameter * Math.cos(scrollCount);
        }
        oldTimestamp = newTimestamp;
        window.requestAnimationFrame(step);
    }
    window.requestAnimationFrame(step);
}
/* 
  Explanation:
  - pi is the length/end point of the cosinus intervall (see below)
  - newTimestamp indicates the current time when callbacks queued by requestAnimationFrame begin to fire.
    (for more information see https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame)
  - newTimestamp - oldTimestamp equals the delta time

    a * cos (bx + c) + d                        | c translates along the x axis = 0
  = a * cos (bx) + d                            | d translates along the y axis = 1 -> only positive y values
  = a * cos (bx) + 1                            | a stretches along the y axis = cosParameter = window.scrollY / 2
  = cosParameter + cosParameter * (cos bx)  | b stretches along the x axis = scrollCount = Math.PI / (scrollDuration / (newTimestamp - oldTimestamp))
  = cosParameter + cosParameter * (cos scrollCount * x)
*/

Note:

  • Duration in milliseconds (1000ms = 1s)
  • Second script uses the cos function. Example curve:

enter image description here

3# Simple scrolling library on Github

How can I print the contents of a hash in Perl?

Here how you can print without using Data::Dumper

print "@{[%hash]}";

Calling Python in Java?

Here a library that lets you write your python scripts once and decide which integration method (Jython, CPython/PyPy via Jep and Py4j) to use at runtime:

https://github.com/subes/invesdwin-context-python

Since each method has its own benefits/drawbacks as explained in the link.

How to detect internet speed in JavaScript?

Even though this is old and answered, i´d like to share the solution i made out of it 2020

it comes with the flexibility to run at anytime and run a callback if greater and or smaller the specified mbps

you can start the test anywhere after you included the testConnectionSpeed Object by running the testConnectionSpeed.run(mbps, morefunction, lessfunction)

for example:

_x000D_
_x000D_
var testConnectionSpeed = {
  imageAddr : "https://upload.wikimedia.org/wikipedia/commons/a/a6/Brandenburger_Tor_abends.jpg", // this is just an example, you rather want an image hosted on your server
  downloadSize : 2707459, // this must match with the image above
  run:function(mbps_max,cb_gt,cb_lt){
    testConnectionSpeed.mbps_max = parseFloat(mbps_max) ? parseFloat(mbps_max) : 0;
    testConnectionSpeed.cb_gt = cb_gt;
    testConnectionSpeed.cb_lt = cb_lt;
    testConnectionSpeed.InitiateSpeedDetection();
  },
  InitiateSpeedDetection: function() {
    window.setTimeout(testConnectionSpeed.MeasureConnectionSpeed, 1);
  },
  result:function(){
    var duration = (endTime - startTime) / 1000;
    var bitsLoaded = testConnectionSpeed.downloadSize * 8;
    var speedBps = (bitsLoaded / duration).toFixed(2);
    var speedKbps = (speedBps / 1024).toFixed(2);
    var speedMbps = (speedKbps / 1024).toFixed(2);
    if(speedMbps >= (testConnectionSpeed.max_mbps ? testConnectionSpeed.max_mbps : 1) ){
      testConnectionSpeed.cb_gt ? testConnectionSpeed.cb_gt(speedMbps) : false;
    }else {
      testConnectionSpeed.cb_lt ? testConnectionSpeed.cb_lt(speedMbps) : false;
    }
  },
  MeasureConnectionSpeed:function() {
    var download = new Image();
    download.onload = function () {
        endTime = (new Date()).getTime();
        testConnectionSpeed.result();
    }
    startTime = (new Date()).getTime();
    var cacheBuster = "?nnn=" + startTime;
    download.src = testConnectionSpeed.imageAddr + cacheBuster;
  }
}




// start test immediatly, you could also call this on any event or whenever you want
testConnectionSpeed.run(1.5, function(mbps){console.log(">= 1.5Mbps ("+mbps+"Mbps)")}, function(mbps){console.log("< 1.5Mbps("+mbps+"Mbps)")} )
_x000D_
_x000D_
_x000D_

I used this successfuly to load lowres media for slow internet connections. You have to play around a bit because on the one hand, the larger the image, the more reasonable the test, on the other hand the test will take way much longer for slow connection and in my case I especially did not want slow connection users to load lots of MBs.

jQuery UI DatePicker to show year only

**NOTE : **If anyone have objection that "why i have answered this Question now !" Because i tried all the answers of this post and got no any solution.So i tried my way and got Solution So i am Sharing to next comers****

HTML

<label for="startYear"> Start Year: </label>
  <input name="startYear" id="startYear" class="date-picker-year" />   

jQuery

 <script type="text/javascript">
        $(function() {
            $('.date-picker-year').datepicker({
                changeYear: true,
                showButtonPanel: true,
                dateFormat: 'yy',
                onClose: function(dateText, inst) { 
                    var year = $("#ui-datepicker-div .ui-datepicker-year :selected").val();
                    $(this).datepicker('setDate', new Date(year, 1));
                }
            });
        $(".date-picker-year").focus(function () {
                $(".ui-datepicker-month").hide();
            });
        });

</script>

RegEx to match stuff between parentheses

var getMatchingGroups = function(s) {
  var r=/\((.*?)\)/g, a=[], m;
  while (m = r.exec(s)) {
    a.push(m[1]);
  }
  return a;
};

getMatchingGroups("something/([0-9])/([a-z])"); // => ["[0-9]", "[a-z]"]

Find index of last occurrence of a sub-string using T-SQL

I know that it will be inefficient but have you considered casting the text field to varchar so that you can use the solution provided by the website you found? I know that this solution would create issues as you could potentially truncate the record if the length in the text field overflowed the length of your varchar (not to mention it would not be very performant).

Since your data is inside a text field (and you are using SQL Server 2000) your options are limited.

Get type of all variables

Designed to do essentially the inverse of what you wanted, here's one of my toolkit toys:

 lstype<-function(type='closure'){
inlist<-ls(.GlobalEnv)
if (type=='function') type <-'closure'
typelist<-sapply(sapply(inlist,get),typeof)
return(names(typelist[typelist==type]))
}

Compare two Timestamp in java

All these solutions don't work for me, although the right way of thinking.

The following works for me:

if(mytime.isAfter(fromtime) || mytime.isBefore(totime) 
    // mytime is between fromtime and totime

Before I tried I thought about your solution with && too

How do I loop through rows with a data reader in C#?

How do I loop through rows with a data reader in C#?

IDataReader.Read() advances the reader to the next row in the resultset.

while(reader.Read()){
    /* do whatever you'd like to do for each row. */
}

So, for each iteration of your loop, you'd do another loop, 0 to reader.FieldCount, and call reader.GetValue(i) for each field.

The bigger question is what kind of structure do you want to use to hold that data?

How to set the font style to bold, italic and underlined in an Android TextView?

This should make your TextView bold, underlined and italic at the same time.

strings.xml

<resources>
    <string name="register"><u><b><i>Copyright</i></b></u></string>
</resources>

To set this String to your TextView, do this in your main.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/textview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:text="@string/register" />

or In JAVA,

TextView textView = new TextView(this);
textView.setText(R.string.register);

Sometimes the above approach will not be helpful when you might have to use Dynamic Text. So in that case SpannableString comes into action.

String tempString="Copyright";
TextView text=(TextView)findViewById(R.id.text);
SpannableString spanString = new SpannableString(tempString);
spanString.setSpan(new UnderlineSpan(), 0, spanString.length(), 0);
spanString.setSpan(new StyleSpan(Typeface.BOLD), 0, spanString.length(), 0);
spanString.setSpan(new StyleSpan(Typeface.ITALIC), 0, spanString.length(), 0);
text.setText(spanString);

OUTPUT

enter image description here

Rotate axis text in python matplotlib

This works for me:

plt.xticks(rotation=90)

How do I read any request header in PHP

You should find all HTTP headers in the $_SERVER global variable prefixed with HTTP_ uppercased and with dashes (-) replaced by underscores (_).

For instance your X-Requested-With can be found in:

$_SERVER['HTTP_X_REQUESTED_WITH']

It might be convenient to create an associative array from the $_SERVER variable. This can be done in several styles, but here's a function that outputs camelcased keys:

$headers = array();
foreach ($_SERVER as $key => $value) {
    if (strpos($key, 'HTTP_') === 0) {
        $headers[str_replace(' ', '', ucwords(str_replace('_', ' ', strtolower(substr($key, 5)))))] = $value;
    }
}

Now just use $headers['XRequestedWith'] to retrieve the desired header.

PHP manual on $_SERVER: http://php.net/manual/en/reserved.variables.server.php

True/False vs 0/1 in MySQL

If you are into performance, then it is worth using ENUM type. It will probably be faster on big tables, due to the better index performance.

The way of using it (source: http://dev.mysql.com/doc/refman/5.5/en/enum.html):

CREATE TABLE shirts (
    name VARCHAR(40),
    size ENUM('x-small', 'small', 'medium', 'large', 'x-large')
);

But, I always say that explaining the query like this:

EXPLAIN SELECT * FROM shirts WHERE size='medium';

will tell you lots of information about your query and help on building a better table structure. For this end, it is usefull to let phpmyadmin Propose a table table structure - but this is more a long time optimisation possibility, when the table is already filled with lots of data.

Operation is not valid due to the current state of the object, when I select a dropdown list

I know an answer has already been accepted for this problem but someone asked in the comments if there was a solution that could be done outside the web.config. I had a ListView producing the exact same error and setting EnableViewState to false resolved this problem for me.

How do negative margins in CSS work and why is (margin-top:-5 != margin-bottom:5)?

I'll try to explain it visually:

_x000D_
_x000D_
/**_x000D_
 * explaining margins_x000D_
 */_x000D_
_x000D_
body {_x000D_
  padding: 3em 15%_x000D_
}_x000D_
_x000D_
.parent {_x000D_
  width: 50%;_x000D_
  width: 400px;_x000D_
  height: 400px;_x000D_
  position: relative;_x000D_
  background: lemonchiffon;_x000D_
}_x000D_
_x000D_
.parent:before,_x000D_
.parent:after {_x000D_
  position: absolute;_x000D_
  content: "";_x000D_
}_x000D_
_x000D_
.parent:before {_x000D_
  top: 0;_x000D_
  bottom: 0;_x000D_
  left: 50%;_x000D_
  border-left: dashed 1px #ccc;_x000D_
}_x000D_
_x000D_
.parent:after {_x000D_
  left: 0;_x000D_
  right: 0;_x000D_
  top: 50%;_x000D_
  border-top: dashed 1px #ccc;_x000D_
}_x000D_
_x000D_
.child {_x000D_
  width: 200px;_x000D_
  height: 200px;_x000D_
  background: rgba(200, 198, 133, .5);_x000D_
}_x000D_
_x000D_
ul {_x000D_
  padding: 5% 20px;_x000D_
}_x000D_
_x000D_
.set1 .child {_x000D_
  margin: 0;_x000D_
  position: relative;_x000D_
}_x000D_
_x000D_
.set2 .child {_x000D_
  margin-left: 75px;_x000D_
  position: relative;_x000D_
}_x000D_
_x000D_
.set3 .child {_x000D_
  margin-left: -75px;_x000D_
  position: relative;_x000D_
}_x000D_
_x000D_
_x000D_
/* position absolute */_x000D_
_x000D_
.set4 .child {_x000D_
  top: 50%;_x000D_
  left: 50%;_x000D_
  margin: 0;_x000D_
  position: absolute;_x000D_
}_x000D_
_x000D_
.set5 .child {_x000D_
  top: 50%;_x000D_
  left: 50%;_x000D_
  margin-left: 75px;_x000D_
  position: absolute;_x000D_
}_x000D_
_x000D_
.set6 .child {_x000D_
  top: 50%; /* level from which margin-top starts _x000D_
 - downwards, in the case of a positive margin_x000D_
 - upwards, in the case of a negative margin _x000D_
 */_x000D_
  left: 50%; /* level from which margin-left starts _x000D_
 - towards right, in the case of a positive margin_x000D_
 - towards left, in the case of a negative margin _x000D_
 */_x000D_
  margin: -75px;_x000D_
  position: absolute;_x000D_
}
_x000D_
<!-- content to be placed inside <body>…</body> -->_x000D_
<h2><code>position: relative;</code></h2>_x000D_
<h3>Set 1</h3>_x000D_
<div class="parent set 1">_x000D_
  <div class="child">_x000D_
    <pre>_x000D_
.set1 .child {_x000D_
  margin: 0;_x000D_
  position: relative;_x000D_
}_x000D_
  </pre>_x000D_
  </div>_x000D_
</div>_x000D_
_x000D_
<h3>Set 2</h3>_x000D_
<div class="parent set2">_x000D_
  <div class="child">_x000D_
    <pre>_x000D_
.set2 .child {_x000D_
  margin-left: 75px;_x000D_
  position: relative;_x000D_
}_x000D_
  </pre>_x000D_
  </div>_x000D_
</div>_x000D_
_x000D_
<h3>Set 3</h3>_x000D_
<div class="parent set3">_x000D_
  <div class="child">_x000D_
    <pre>_x000D_
.set3 .child {_x000D_
  margin-left: -75px;_x000D_
  position: relative;_x000D_
}_x000D_
  </pre>_x000D_
  </div>_x000D_
</div>_x000D_
_x000D_
<h2><code>position: absolute;</code></h2>_x000D_
_x000D_
<h3>Set 4</h3>_x000D_
<div class="parent set4">_x000D_
  <div class="child">_x000D_
    <pre>_x000D_
.set4 .child {_x000D_
  top: 50%;_x000D_
  left: 50%;_x000D_
  margin: 0;_x000D_
  position: absolute;_x000D_
}_x000D_
  </pre>_x000D_
  </div>_x000D_
</div>_x000D_
_x000D_
<h3>Set 5</h3>_x000D_
<div class="parent set5">_x000D_
  <div class="child">_x000D_
    <pre>_x000D_
.set5 .child {_x000D_
  top: 50%;_x000D_
  left: 50%;_x000D_
  margin-left: 75px;_x000D_
  position: absolute;_x000D_
}_x000D_
  </pre>_x000D_
  </div>_x000D_
</div>_x000D_
_x000D_
<h3>Set 6</h3>_x000D_
<div class="parent set6">_x000D_
  <div class="child">_x000D_
    <pre>_x000D_
.set6 .child {_x000D_
  top: 50%;_x000D_
  left: 50%;_x000D_
  margin: -75px;_x000D_
  position: absolute;_x000D_
}_x000D_
  </pre>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Why I'm getting 'Non-static method should not be called statically' when invoking a method in a Eloquent model?

TL;DR. You can get around this by expressing your queries as MyModel::query()->find(10); instead of MyModel::find(10);.

To the best of my knowledge, starting PhpStorm 2017.2 code inspection fails for methods such as MyModel::where(), MyModel::find(), etc (check this thread). This could get quite annoying, when you try let's say to use PhpStorm's Git integration before committing your code, PhpStorm won't stop complaining about these static method call warnings.

One elegant way (IMOO) to get around this is to explicitly call ::query() wherever it makes sense to. This will let you benefit from a free auto-completion and a nice query formatting.

Examples

Snippet where inspection complains about static method calls

$myModel = MyModel::find(10); // static call complaint

// another poorly formatted query with code inspection complaints
$myFilteredModels = MyModel::where('is_beautiful', true)
    ->where('is_not_smart', false)
    ->get();

Well formatted code with no complaints

$myModel = MyModel::query()->find(10);

// a nicely formatted query with no complaints
$myFilteredModels = MyModel::query()
    ->where('is_beautiful', true)
    ->where('is_not_smart', false)
    ->get();

Using Javascript: How to create a 'Go Back' link that takes the user to a link if there's no history for the tab or window?

The reason on using the return:false; is well explained on this other question.

For the other issue, you can check for the referrer to see if it is empty:

    function backAway(){
        if (document.referrer == "") { //alternatively, window.history.length == 0
            window.location = "http://www.example.com";
        } else {
            history.back();
        }
    }

<a href="#" onClick="backAway()">Back Button Here.</a>

Checkout Jenkins Pipeline Git SCM with credentials?

You can use the following in a pipeline:

git branch: 'master',
    credentialsId: '12345-1234-4696-af25-123455',
    url: 'ssh://[email protected]:company/repo.git'

If you're using the ssh url then your credentials must be username + private key. If you're using the https clone url instead of the ssh one, then your credentials should be username + password.

View a file in a different Git branch without changing branches

Add the following to your ~/.gitconfig file

[alias]
  cat = "!git show \"$1:$2\" #"

And then try this

git cat BRANCHNAME FILEPATH

Personally I prefer separate parameters without a colon. Why? This choice mirrors the parameters of the checkout command, which I tend to use rather frequently and I find it thus much easier to remember than the bizarro colon-separated parameter of the show command.

java.util.NoSuchElementException - Scanner reading user input

the reason of the exception has been explained already, however the suggested solution isn't really the best.

You should create a class that keeps a Scanner as private using Singleton Pattern, that makes that scanner unique on your code.

Then you can implement the methods you need or you can create a getScanner ( not recommended ) and you can control it with a private boolean, something like alreadyClosed.

If you are not aware how to use Singleton Pattern, here's a example:

public class Reader {
    
    
    private Scanner reader;
    private static Reader singleton = null;
    private boolean alreadyClosed;
    
    private Reader() {
        alreadyClosed = false;
        reader = new Scanner(System.in);
    }
    
    public static Reader getInstance() {
        if(singleton == null) {
            singleton = new Reader();
        }
        return singleton;
    }
    
    public int nextInt() throws AlreadyClosedException {
        if(!alreadyClosed) {
            return reader.nextInt();
        }
        throw new AlreadyClosedException(); //Custom exception
    }
    
    public double nextDouble() throws AlreadyClosedException {
        if(!alreadyClosed) {
            return reader.nextDouble();
        }
        throw new AlreadyClosedException();
    }
    
    public String nextLine() throws AlreadyClosedException {
        if(!alreadyClosed) {
            return reader.nextLine();
        }
        throw new AlreadyClosedException();
    }
    
    public void close() {
        alreadyClosed = true;
        reader.close();
    }   
}

Strings in C, how to get subString

Generalized:

char* subString (const char* input, int offset, int len, char* dest)
{
  int input_len = strlen (input);

  if (offset + len > input_len)
  {
     return NULL;
  }

  strncpy (dest, input + offset, len);
  return dest;
}

char dest[80];
const char* source = "hello world";

if (subString (source, 0, 5, dest))
{
  printf ("%s\n", dest);
}

Efficient way to remove keys with empty strings from a dict

Some of Methods mentioned above ignores if there are any integers and float with values 0 & 0.0

If someone wants to avoid the above can use below code(removes empty strings and None values from nested dictionary and nested list):

def remove_empty_from_dict(d):
    if type(d) is dict:
        _temp = {}
        for k,v in d.items():
            if v == None or v == "":
                pass
            elif type(v) is int or type(v) is float:
                _temp[k] = remove_empty_from_dict(v)
            elif (v or remove_empty_from_dict(v)):
                _temp[k] = remove_empty_from_dict(v)
        return _temp
    elif type(d) is list:
        return [remove_empty_from_dict(v) for v in d if( (str(v).strip() or str(remove_empty_from_dict(v)).strip()) and (v != None or remove_empty_from_dict(v) != None))]
    else:
        return d

JQuery to load Javascript file dynamically

I realize I am a little late here, (5 years or so), but I think there is a better answer than the accepted one as follows:

$("#addComment").click(function() {
    if(typeof TinyMCE === "undefined") {
        $.ajax({
            url: "tinymce.js",
            dataType: "script",
            cache: true,
            success: function() {
                TinyMCE.init();
            }
        });
    }
});

The getScript() function actually prevents browser caching. If you run a trace you will see the script is loaded with a URL that includes a timestamp parameter:

http://www.yoursite.com/js/tinymce.js?_=1399055841840

If a user clicks the #addComment link multiple times, tinymce.js will be re-loaded from a differently timestampped URL. This defeats the purpose of browser caching.

===

Alternatively, in the getScript() documentation there is a some sample code that demonstrates how to enable caching by creating a custom cachedScript() function as follows:

jQuery.cachedScript = function( url, options ) {

    // Allow user to set any option except for dataType, cache, and url
    options = $.extend( options || {}, {
        dataType: "script",
        cache: true,
        url: url
    });

    // Use $.ajax() since it is more flexible than $.getScript
    // Return the jqXHR object so we can chain callbacks
    return jQuery.ajax( options );
};

// Usage
$.cachedScript( "ajax/test.js" ).done(function( script, textStatus ) {
    console.log( textStatus );
});

===

Or, if you want to disable caching globally, you can do so using ajaxSetup() as follows:

$.ajaxSetup({
    cache: true
});

How to create table using select query in SQL Server?

An example statement that uses a sub-select :

select * into MyNewTable
from
(
select 
  * 
from 
[SomeOtherTablename]
where 
  EventStartDatetime >= '01/JAN/2018' 
)
) mysourcedata
;

note that the sub query must be given a name .. any name .. e.g. above example gives the subquery a name of mysourcedata. Without this a syntax error is issued in SQL*server 2012.

The database should reply with a message like: (9999 row(s) affected)

Get difference between 2 dates in JavaScript?

var date1 = new Date("7/11/2010");
var date2 = new Date("8/11/2010");
var diffDays = parseInt((date2 - date1) / (1000 * 60 * 60 * 24), 10); 

alert(diffDays )

HTML / CSS table with GRIDLINES

Via css. Put this inside the <head> tag.

<style type="text/css" media="screen">

table{
border-collapse:collapse;
border:1px solid #FF0000;
}

table td{
border:1px solid #FF0000;
}
</style>

Uncaught (in promise) TypeError: Failed to fetch and Cors error

you can use solutions without adding "Access-Control-Allow-Origin": "*", if your server is already using Proxy gateway this issue will not happen because the front and backend will be route in the same IP and port in client side but for development, you need one of this three solution if you don't need extra code 1- simulate the real environment by using a proxy server and configure the front and backend in the same port

2- if you using Chrome you can use the extension called Allow-Control-Allow-Origin: * it will help you to avoid this problem

3- you can use the code but some browsers versions may not support that so try to use one of the previous solutions

the best solution is using a proxy like ngnix its easy to configure and it will simulate the real situation of the production deployment

How to call a function, PostgreSQL

We can have two ways of calling the functions written in pgadmin for postgre sql database.

Suppose we have defined the function as below:

CREATE OR REPLACE FUNCTION helloWorld(name text) RETURNS void AS $helloWorld$
DECLARE
BEGIN
    RAISE LOG 'Hello, %', name;
END;
$helloWorld$ LANGUAGE plpgsql;

We can call the function helloworld in one of the following way:

SELECT "helloworld"('myname');

SELECT public.helloworld('myname')

MySQL: how to get the difference between two timestamps in seconds

UNIX_TIMESTAMP(ts1) - UNIX_TIMESTAMP(ts2)

If you want an unsigned difference, add an ABS() around the expression.

Alternatively, you can use TIMEDIFF(ts1, ts2) and then convert the time result to seconds with TIME_TO_SEC().

How to reload a page after the OK click on the Alert Page

Try this code..

IN PHP Code

echo "<script type='text/javascript'>".
      "alert('Success to add the task to a project.');
       location.reload;".
     "</script>";

IN Javascript

function refresh()
{
    alert("click ok to refresh  page");
    location.reload();
}

How do I edit SSIS package files?

Additional answer for Visual Studio 2012:

You can open .dtsx along with their corresponding .dtproj project files with the SQL Server Data Tools Business Intelligence (SSDT-BI) add-in:

http://blogs.msdn.com/b/mattm/archive/2013/03/07/sql-server-data-tools-business-intelligence-for-visual-studio-2012-released-online.aspx

http://www.microsoft.com/download/details.aspx?id=36843

If the projects were created with an earlier version they will require an upgrade.

I did have some hang ups installing this - the install would spin on "Install_VSTA2012_CPU32_Action" and similar steps. It wasn't until I did a repair inside of the same installer did it install completely.

Spring Boot REST API - request timeout?

I would suggest you have a look at the Spring Cloud Netflix Hystrix starter to handle potentially unreliable/slow remote calls. It implements the Circuit Breaker pattern, that is intended for precisely this sorta thing.

See offcial docs for more information.

Understanding implicit in Scala

A very basic example of Implicits in scala.

Implicit parameters:

val value = 10
implicit val multiplier = 3
def multiply(implicit by: Int) = value * by
val result = multiply // implicit parameter wiil be passed here
println(result) // It will print 30 as a result

Note: Here multiplier will be implicitly passed into the function multiply. Missing parameters to the function call are looked up by type in the current scope meaning that code will not compile if there is no implicit variable of type Int in the scope.

Implicit conversions:

implicit def convert(a: Double): Int = a.toInt
val res = multiply(2.0) // Type conversions with implicit functions
println(res)  // It will print 20 as a result

Note: When we call multiply function passing a double value, the compiler will try to find the conversion implicit function in the current scope, which converts Int to Double (As function multiply accept Int parameter). If there is no implicit convert function then the compiler will not compile the code.

TypeError: 'str' object cannot be interpreted as an integer

I'm guessing you're running python3, in which input(prompt) returns a string. Try this.

x=int(input('prompt'))
y=int(input('prompt'))

C++: Rounding up to the nearest multiple of a number

I'm using:

template <class _Ty>
inline _Ty n_Align_Up(_Ty n_x, _Ty n_alignment)
{
    assert(n_alignment > 0);
    //n_x += (n_x >= 0)? n_alignment - 1 : 1 - n_alignment; // causes to round away from zero (greatest absolute value)
    n_x += (n_x >= 0)? n_alignment - 1 : -1; // causes to round up (towards positive infinity)
    //n_x += (_Ty(-(n_x >= 0)) & n_alignment) - 1; // the same as above, avoids branch and integer multiplication
    //n_x += n_alignment - 1; // only works for positive numbers (fastest)
    return n_x - n_x % n_alignment; // rounds negative towards zero
}

and for powers of two:

template <class _Ty>
bool b_Is_POT(_Ty n_x)
{
    return !(n_x & (n_x - 1));
}

template <class _Ty>
inline _Ty n_Align_Up_POT(_Ty n_x, _Ty n_pot_alignment)
{
    assert(n_pot_alignment > 0);
    assert(b_Is_POT(n_pot_alignment)); // alignment must be power of two
    -- n_pot_alignment;
    return (n_x + n_pot_alignment) & ~n_pot_alignment; // rounds towards positive infinity (i.e. negative towards zero)
}

Note that both of those round negative values towards zero (that means round to positive infinity for all values), neither of them relies on signed overflow (which is undefined in C/C++).

This gives:

n_Align_Up(10, 100) = 100
n_Align_Up(110, 100) = 200
n_Align_Up(0, 100) = 0
n_Align_Up(-10, 100) = 0
n_Align_Up(-110, 100) = -100
n_Align_Up(-210, 100) = -200
n_Align_Up_POT(10, 128) = 128
n_Align_Up_POT(130, 128) = 256
n_Align_Up_POT(0, 128) = 0
n_Align_Up_POT(-10, 128) = 0
n_Align_Up_POT(-130, 128) = -128
n_Align_Up_POT(-260, 128) = -256

The transaction log for database is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc column in sys.databases

As an aside, it is always a good practice (and possibly a solution for this type of issue) to delete a large number of rows by using batches:

WHILE EXISTS (SELECT 1 
              FROM   YourTable 
              WHERE  <yourCondition>) 
  DELETE TOP(10000) FROM YourTable 
  WHERE  <yourCondition>

grep using a character vector with multiple patterns

To add to Brian Diggs answer.

another way using grepl will return a data frame containing all your values.

toMatch <- myfile$Letter

matches <- myfile[grepl(paste(toMatch, collapse="|"), myfile$Letter), ]

matches

Letter Firstname
1     A1      Alex 
2     A6      Alex 
4     A1       Bob 
5     A9     Chris 
6     A6     Chris

Maybe a bit cleaner... maybe?

MySQL - Rows to Columns

My solution :

select h.hostid, sum(ifnull(h.A,0)) as A, sum(ifnull(h.B,0)) as B, sum(ifnull(h.C,0)) as  C from (
select
hostid,
case when itemName = 'A' then itemvalue end as A,
case when itemName = 'B' then itemvalue end as B,
case when itemName = 'C' then itemvalue end as C
  from history 
) h group by hostid

It produces the expected results in the submitted case.

How do detect Android Tablets in general. Useragent?

The issue is that the Android User-Agent is a general User-Agent and there is no difference between tablet Android and mobile Android.

This is incorrect. Mobile Android has "Mobile" string in the User-Agent header. Tablet Android does not.

But it is worth mentioning that there are quite a few tablets that report "Mobile" Safari in the userAgent and the latter is not the only/solid way to differentiate between Mobile and Tablet.

Switch on Enum in Java

Actually you can use a switch statement with Strings in Java...unfortunately this is a new feature of Java 7, and most people are not using Java 7 yet because it's so new.

Comparing boxed Long values 127 and 128

TL;DR

Java caches boxed Integer instances from -128 to 127. Since you are using == to compare objects references instead of values, only cached objects will match. Either work with long unboxed primitive values or use .equals() to compare your Long objects.

Long (pun intended) version

Why there is problem in comparing Long variable with value greater than 127? If the data type of above variable is primitive (long) then code work for all values.

Java caches Integer objects instances from the range -128 to 127. That said:

  • If you set to N Long variables the value 127 (cached), the same object instance will be pointed by all references. (N variables, 1 instance)
  • If you set to N Long variables the value 128 (not cached), you will have an object instance pointed by every reference. (N variables, N instances)

That's why this:

Long val1 = 127L;
Long val2 = 127L;

System.out.println(val1 == val2);

Long val3 = 128L;
Long val4 = 128L;

System.out.println(val3 == val4);

Outputs this:

true
false

For the 127L value, since both references (val1 and val2) point to the same object instance in memory (cached), it returns true.

On the other hand, for the 128 value, since there is no instance for it cached in memory, a new one is created for any new assignments for boxed values, resulting in two different instances (pointed by val3 and val4) and returning false on the comparison between them.

That happens solely because you are comparing two Long object references, not long primitive values, with the == operator. If it wasn't for this Cache mechanism, these comparisons would always fail, so the real problem here is comparing boxed values with == operator.

Changing these variables to primitive long types will prevent this from happening, but in case you need to keep your code using Long objects, you can safely make these comparisons with the following approaches:

System.out.println(val3.equals(val4));                     // true
System.out.println(val3.longValue() == val4.longValue());  // true
System.out.println((long)val3 == (long)val4);              // true

(Proper null checking is necessary, even for castings)

IMO, it's always a good idea to stick with .equals() methods when dealing with Object comparisons.

Reference links:

Converting two lists into a matrix

Simple you can try this

a=list(zip(portfolio, index))

HorizontalAlignment=Stretch, MaxWidth, and Left aligned at the same time?

Maybe I can still help somebody out who bumps into this question, because this is a very old issue.

I needed this as well and wrote a behavior to take care of this. So here is the behavior:

public class StretchMaxWidthBehavior : Behavior<FrameworkElement>
{        
    protected override void OnAttached()
    {
        base.OnAttached();
        ((FrameworkElement)this.AssociatedObject.Parent).SizeChanged += this.OnSizeChanged;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        ((FrameworkElement)this.AssociatedObject.Parent).SizeChanged -= this.OnSizeChanged;
    }

    private void OnSizeChanged(object sender, SizeChangedEventArgs e)
    {
        this.SetAlignments();
    }

    private void SetAlignments()
    {
        var slot = LayoutInformation.GetLayoutSlot(this.AssociatedObject);
        var newWidth = slot.Width;
        var newHeight = slot.Height;

        if (!double.IsInfinity(this.AssociatedObject.MaxWidth))
        {
            if (this.AssociatedObject.MaxWidth < newWidth)
            {
                this.AssociatedObject.HorizontalAlignment = HorizontalAlignment.Left;
                this.AssociatedObject.Width = this.AssociatedObject.MaxWidth;
            }
            else
            {
                this.AssociatedObject.HorizontalAlignment = HorizontalAlignment.Stretch;
                this.AssociatedObject.Width = double.NaN;
            }
        }

        if (!double.IsInfinity(this.AssociatedObject.MaxHeight))
        {
            if (this.AssociatedObject.MaxHeight < newHeight)
            {
                this.AssociatedObject.VerticalAlignment = VerticalAlignment.Top;
                this.AssociatedObject.Height = this.AssociatedObject.MaxHeight;
            }
            else
            {
                this.AssociatedObject.VerticalAlignment = VerticalAlignment.Stretch;
                this.AssociatedObject.Height = double.NaN;
            }
        }
    }
}

Then you can use it like so:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition />
    </Grid.ColumnDefinitions>

    <TextBlock Grid.Column="0" Text="Label" />
    <TextBox Grid.Column="1" MaxWidth="600">
          <i:Interaction.Behaviors>                       
               <cbh:StretchMaxWidthBehavior/>
          </i:Interaction.Behaviors>
    </TextBox>
</Grid>

And finally to forget to use the System.Windows.Interactivity namespace to use the behavior.

MVC [HttpPost/HttpGet] for Action

You cant combine this to attributes.

But you can put both on one action method but you can encapsulate your logic into a other method and call this method from both actions.

The ActionName Attribute allows to have 2 ActionMethods with the same name.

[HttpGet]
public ActionResult MyMethod()
{
    return MyMethodHandler();
}

[HttpPost]
[ActionName("MyMethod")]
public ActionResult MyMethodPost()
{
    return MyMethodHandler();
}

private ActionResult MyMethodHandler()
{
    // handle the get or post request
    return View("MyMethod");
}

Query to list all users of a certain group

For Active Directory users, an alternative way to do this would be -- assuming all your groups are stored in OU=Groups,DC=CorpDir,DC=QA,DC=CorpName -- to use the query (&(objectCategory=group)(CN=GroupCN)). This will work well for all groups with less than 1500 members. If you want to list all members of a large AD group, the same query will work, but you'll have to use ranged retrieval to fetch all the members, 1500 records at a time.

The key to performing ranged retrievals is to specify the range in the attributes using this syntax: attribute;range=low-high. So to fetch all members of an AD Group with 3000 members, first run the above query asking for the member;range=0-1499 attribute to be returned, then for the member;range=1500-2999 attribute.

How to add form validation pattern in Angular 2?

custom validation step by step

Html template

  <form [ngFormModel]="demoForm">
  <input  
  name="NotAllowSpecialCharacters"    
  type="text"                      
  #demo="ngForm"
  [ngFormControl] ="demoForm.controls['spec']"
  >

 <div class='error' *ngIf="demo.control.touched">
   <div *ngIf="demo.control.hasError('required')"> field  is required.</div>
   <div *ngIf="demo.control.hasError('invalidChar')">Special Characters are not Allowed</div>
 </div>
  </form>

Component App.ts

import {Control, ControlGroup, FormBuilder, Validators, NgForm, NgClass} from 'angular2/common';
import {CustomValidator} from '../../yourServices/validatorService';

under class define

 demoForm: ControlGroup;
constructor( @Inject(FormBuilder) private Fb: FormBuilder ) {
    this.demoForm = Fb.group({
       spec: new Control('', Validators.compose([Validators.required,   CustomValidator.specialCharValidator])),
      })
}

under {../../yourServices/validatorService.ts}

export class CustomValidator {
    static specialCharValidator(control: Control): { [key: string]: any } {
   if (control.value) {
       if (!control.value.match(/[-!$%^&*()_+|~=`{}\[\]:";#@'<>?,.\/]/)) {            
           return null;
       }
       else {            
           return { 'invalidChar': true };
       }
   }

 }

 }

Prevent browser caching of AJAX call result

Personally I feel that the query string method is more reliable than trying to set headers on the server - there's no guarantee that a proxy or browser won't just cache it anyway (some browsers are worse than others - naming no names).

I usually use Math.random() but I don't see anything wrong with using the date (you shouldn't be doing AJAX requests fast enough to get the same value twice).

Alternative to iFrames with HTML5

No, there isn't an equivalent. The <iframe> element is still valid in HTML5. Depending on what exact interaction you need there might be different APIs. For example there's the postMessage method which allows you to achieve cross domain javascript interaction. But if you want to display cross domain HTML contents (styled with CSS and made interactive with javascript) iframe stays as a good way to do.

Process list on Linux via Python

IMO looking at the /proc filesystem is less nasty than hacking the text output of ps.

import os
pids = [pid for pid in os.listdir('/proc') if pid.isdigit()]

for pid in pids:
    try:
        print open(os.path.join('/proc', pid, 'cmdline'), 'rb').read().split('\0')
    except IOError: # proc has already terminated
        continue

Using an array from Observable Object with ngFor and Async Pipe Angular 2

Who ever also stumbles over this post.

I belive is the correct way:

  <div *ngFor="let appointment of (_nextFourAppointments | async).availabilities;"> 
    <div>{{ appointment }}</div>
  </div>

Does Python have a ternary conditional operator?

Python has a ternary form for assignments; however there may be even a shorter form that people should be aware of.

It's very common to need to assign to a variable one value or another depending on a condition.

>>> li1 = None
>>> li2 = [1, 2, 3]
>>> 
>>> if li1:
...     a = li1
... else:
...     a = li2
...     
>>> a
[1, 2, 3]

^ This is the long form for doing such assignments.

Below is the ternary form. But this isn't most succinct way - see last example.

>>> a = li1 if li1 else li2
>>> 
>>> a
[1, 2, 3]
>>> 

With Python, you can simply use or for alternative assignments.

>>> a = li1 or li2
>>> 
>>> a
[1, 2, 3]
>>> 

The above works since li1 is None and the interp treats that as False in logic expressions. The interp then moves on and evaluates the second expression, which is not None and it's not an empty list - so it gets assigned to a.

This also works with empty lists. For instance, if you want to assign a whichever list has items.

>>> li1 = []
>>> li2 = [1, 2, 3]
>>> 
>>> a = li1 or li2
>>> 
>>> a
[1, 2, 3]
>>> 

Knowing this, you can simply such assignments whenever you encounter them. This also works with strings and other iterables. You could assign a whichever string isn't empty.

>>> s1 = ''
>>> s2 = 'hello world'
>>> 
>>> a = s1 or s2
>>> 
>>> a
'hello world'
>>> 

I always liked the C ternary syntax, but Python takes it a step further!

I understand that some may say this isn't a good stylistic choice because it relies on mechanics that aren't immediately apparent to all developers. I personally disagree with that viewpoint. Python is a syntax rich language with lots of idiomatic tricks that aren't immediately apparent to the dabler. But the more you learn and understand the mechanics of the underlying system, the more you appreciate it.

Select multiple rows with the same value(s)

One way of doing this is via an exists clause:

select * from genes g
where exists
(select null from genes g1
 where g.locus = g1.locus and g.chromosome = g1.chromosome and g.id <> g1.id)

Alternatively, in MySQL you can get a summary of all matching ids with a single table access, using group_concat:

select group_concat(id) matching_ids, chromosome, locus 
from genes
group by chromosome, locus
having count(*) > 1

Scala: write string to file in one statement

A concise one line:

import java.io.PrintWriter
new PrintWriter("filename") { write("file contents"); close }

Check if a value is in an array or not with Excel VBA

You can brute force it like this:

Public Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
    Dim i
    For i = LBound(arr) To UBound(arr)
        If arr(i) = stringToBeFound Then
            IsInArray = True
            Exit Function
        End If
    Next i
    IsInArray = False

End Function

Use like

IsInArray("example", Array("example", "someother text", "more things", "and another"))

How to find out if an installed Eclipse is 32 or 64 bit version?

Go to the Eclipse base folder ? open eclipse.ini ? you will find the below line at line no 4:

plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.200.v20150204-1316 plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.200.v20120913-144807

As you can see, line 1 is of 64-bit Eclipse. It contains x86_64 and line 2 is of 32-bit Eclipse. It contains x_86.

For 32-bit Eclipse only x86 will be present and for 64-bit Eclipse x86_64 will be present.

Shared-memory objects in multiprocessing

I run into the same problem and wrote a little shared-memory utility class to work around it.

I'm using multiprocessing.RawArray (lockfree), and also the access to the arrays is not synchronized at all (lockfree), be careful not to shoot your own feet.

With the solution I get speedups by a factor of approx 3 on a quad-core i7.

Here's the code: Feel free to use and improve it, and please report back any bugs.

'''
Created on 14.05.2013

@author: martin
'''

import multiprocessing
import ctypes
import numpy as np

class SharedNumpyMemManagerError(Exception):
    pass

'''
Singleton Pattern
'''
class SharedNumpyMemManager:    

    _initSize = 1024

    _instance = None

    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            cls._instance = super(SharedNumpyMemManager, cls).__new__(
                                cls, *args, **kwargs)
        return cls._instance        

    def __init__(self):
        self.lock = multiprocessing.Lock()
        self.cur = 0
        self.cnt = 0
        self.shared_arrays = [None] * SharedNumpyMemManager._initSize

    def __createArray(self, dimensions, ctype=ctypes.c_double):

        self.lock.acquire()

        # double size if necessary
        if (self.cnt >= len(self.shared_arrays)):
            self.shared_arrays = self.shared_arrays + [None] * len(self.shared_arrays)

        # next handle
        self.__getNextFreeHdl()        

        # create array in shared memory segment
        shared_array_base = multiprocessing.RawArray(ctype, np.prod(dimensions))

        # convert to numpy array vie ctypeslib
        self.shared_arrays[self.cur] = np.ctypeslib.as_array(shared_array_base)

        # do a reshape for correct dimensions            
        # Returns a masked array containing the same data, but with a new shape.
        # The result is a view on the original array
        self.shared_arrays[self.cur] = self.shared_arrays[self.cnt].reshape(dimensions)

        # update cnt
        self.cnt += 1

        self.lock.release()

        # return handle to the shared memory numpy array
        return self.cur

    def __getNextFreeHdl(self):
        orgCur = self.cur
        while self.shared_arrays[self.cur] is not None:
            self.cur = (self.cur + 1) % len(self.shared_arrays)
            if orgCur == self.cur:
                raise SharedNumpyMemManagerError('Max Number of Shared Numpy Arrays Exceeded!')

    def __freeArray(self, hdl):
        self.lock.acquire()
        # set reference to None
        if self.shared_arrays[hdl] is not None: # consider multiple calls to free
            self.shared_arrays[hdl] = None
            self.cnt -= 1
        self.lock.release()

    def __getArray(self, i):
        return self.shared_arrays[i]

    @staticmethod
    def getInstance():
        if not SharedNumpyMemManager._instance:
            SharedNumpyMemManager._instance = SharedNumpyMemManager()
        return SharedNumpyMemManager._instance

    @staticmethod
    def createArray(*args, **kwargs):
        return SharedNumpyMemManager.getInstance().__createArray(*args, **kwargs)

    @staticmethod
    def getArray(*args, **kwargs):
        return SharedNumpyMemManager.getInstance().__getArray(*args, **kwargs)

    @staticmethod    
    def freeArray(*args, **kwargs):
        return SharedNumpyMemManager.getInstance().__freeArray(*args, **kwargs)

# Init Singleton on module load
SharedNumpyMemManager.getInstance()

if __name__ == '__main__':

    import timeit

    N_PROC = 8
    INNER_LOOP = 10000
    N = 1000

    def propagate(t):
        i, shm_hdl, evidence = t
        a = SharedNumpyMemManager.getArray(shm_hdl)
        for j in range(INNER_LOOP):
            a[i] = i

    class Parallel_Dummy_PF:

        def __init__(self, N):
            self.N = N
            self.arrayHdl = SharedNumpyMemManager.createArray(self.N, ctype=ctypes.c_double)            
            self.pool = multiprocessing.Pool(processes=N_PROC)

        def update_par(self, evidence):
            self.pool.map(propagate, zip(range(self.N), [self.arrayHdl] * self.N, [evidence] * self.N))

        def update_seq(self, evidence):
            for i in range(self.N):
                propagate((i, self.arrayHdl, evidence))

        def getArray(self):
            return SharedNumpyMemManager.getArray(self.arrayHdl)

    def parallelExec():
        pf = Parallel_Dummy_PF(N)
        print(pf.getArray())
        pf.update_par(5)
        print(pf.getArray())

    def sequentialExec():
        pf = Parallel_Dummy_PF(N)
        print(pf.getArray())
        pf.update_seq(5)
        print(pf.getArray())

    t1 = timeit.Timer("sequentialExec()", "from __main__ import sequentialExec")
    t2 = timeit.Timer("parallelExec()", "from __main__ import parallelExec")

    print("Sequential: ", t1.timeit(number=1))    
    print("Parallel: ", t2.timeit(number=1))

How do I tell if a variable has a numeric value in Perl?

Check out the CPAN module Regexp::Common. I think it does exactly what you need and handles all the edge cases (e.g. real numbers, scientific notation, etc). e.g.

use Regexp::Common;
if ($var =~ /$RE{num}{real}/) { print q{a number}; }

add commas to a number in jQuery

Take a look at Numeral.js. It can format numbers, currency, percentages and has support for localization.

How can I set an SQL Server connection string?

We can simply connect to the database like this:

 uid=username;pwd=password;database=databasename;server=servername

For example:

string connectionString = @"uid=spacecraftU1;pwd=Appolo11;
                            database=spacecraft_db;
                            server=DESKTOP-99K0FRS\\PRANEETHDB";
SqlConnection con = new SqlConnection(connectionString);

How can I inject a property value into a Spring Bean which was configured using annotations?

You can do this in Spring 3 using EL support. Example:

@Value("#{systemProperties.databaseName}")
public void setDatabaseName(String dbName) { ... }

@Value("#{strategyBean.databaseKeyGenerator}")
public void setKeyGenerator(KeyGenerator kg) { ... }

systemProperties is an implicit object and strategyBean is a bean name.

One more example, which works when you want to grab a property from a Properties object. It also shows that you can apply @Value to fields:

@Value("#{myProperties['github.oauth.clientId']}")
private String githubOauthClientId;

Here is a blog post I wrote about this for a little more info.

Remove all of x axis labels in ggplot

You have to set to element_blank() in theme() elements you need to remove

ggplot(data = diamonds, mapping = aes(x = clarity)) + geom_bar(aes(fill = cut))+
  theme(axis.title.x=element_blank(),
        axis.text.x=element_blank(),
        axis.ticks.x=element_blank())

Calculate days between two Dates in Java 8

I know this question is for Java 8, but with Java 9 you could use:

public static List<LocalDate> getDatesBetween(LocalDate startDate, LocalDate endDate) {
    return startDate.datesUntil(endDate)
      .collect(Collectors.toList());
}

How can I add C++11 support to Code::Blocks compiler?

A simple way is to write:

-std=c++11

in the Other Options section of the compiler flags. You could do this on a per-project basis (Project -> Build Options), and/or set it as a default option in the Settings -> Compilers part.

Some projects may require -std=gnu++11 which is like C++11 but has some GNU extensions enabled.

If using g++ 4.9, you can use -std=c++14 or -std=gnu++14.

How to connect to Mysql Server inside VirtualBox Vagrant?

I came across this issue recently. I used PuPHPet to generate a config.

To connect to MySQL through SSH, the "vagrant" password was not working for me, instead I had to authenticate through the SSH key file.

To connect with MySQL Workbench

Connection method

Standard TCP/IP over SSH

SSH

Hostname: 127.0.0.1:2222 (forwarded SSH port)
Username: vagrant
Password: (do not use)
SSH Key File: C:\vagrantpath\puphpet\files\dot\ssh\insecure_private_key
              (Locate your insercure_private_key)

MySQL

Server Port: 3306
username: (root, or username)
password: (password)

Test the connection.

How do I dispatch_sync, dispatch_async, dispatch_after, etc in Swift 3, Swift 4, and beyond?

Since the beginning, Swift has provided some facilities for making ObjC and C more Swifty, adding more with each version. Now, in Swift 3, the new "import as member" feature lets frameworks with certain styles of C API -- where you have a data type that works sort of like a class, and a bunch of global functions to work with it -- act more like Swift-native APIs. The data types import as Swift classes, their related global functions import as methods and properties on those classes, and some related things like sets of constants can become subtypes where appropriate.

In Xcode 8 / Swift 3 beta, Apple has applied this feature (along with a few others) to make the Dispatch framework much more Swifty. (And Core Graphics, too.) If you've been following the Swift open-source efforts, this isn't news, but now is the first time it's part of Xcode.

Your first step on moving any project to Swift 3 should be to open it in Xcode 8 and choose Edit > Convert > To Current Swift Syntax... in the menu. This will apply (with your review and approval) all of the changes at once needed for all the renamed APIs and other changes. (Often, a line of code is affected by more than one of these changes at once, so responding to error fix-its individually might not handle everything right.)

The result is that the common pattern for bouncing work to the background and back now looks like this:

// Move to a background thread to do some long running work
DispatchQueue.global(qos: .userInitiated).async {
    let image = self.loadOrGenerateAnImage()
    // Bounce back to the main thread to update the UI
    DispatchQueue.main.async {
        self.imageView.image = image
    }
}

Note we're using .userInitiated instead of one of the old DISPATCH_QUEUE_PRIORITY constants. Quality of Service (QoS) specifiers were introduced in OS X 10.10 / iOS 8.0, providing a clearer way for the system to prioritize work and deprecating the old priority specifiers. See Apple's docs on background work and energy efficiency for details.

By the way, if you're keeping your own queues to organize work, the way to get one now looks like this (notice that DispatchQueueAttributes is an OptionSet, so you use collection-style literals to combine options):

class Foo { 
    let queue = DispatchQueue(label: "com.example.my-serial-queue",
                           attributes: [.serial, .qosUtility])
    func doStuff() {
        queue.async {
            print("Hello World")
        }
    }
}

Using dispatch_after to do work later? That's a method on queues, too, and it takes a DispatchTime, which has operators for various numeric types so you can just add whole or fractional seconds:

DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) { // in half a second...
    print("Are we there yet?")
}

You can find your way around the new Dispatch API by opening its interface in Xcode 8 -- use Open Quickly to find the Dispatch module, or put a symbol (like DispatchQueue) in your Swift project/playground and command-click it, then brouse around the module from there. (You can find the Swift Dispatch API in Apple's spiffy new API Reference website and in-Xcode doc viewer, but it looks like the doc content from the C version hasn't moved into it just yet.)

See the Migration Guide for more tips.

How to pass parameters or arguments into a gradle task

Its nothing more easy.

run command: ./gradlew clean -PjobId=9999

and

in gradle use: println(project.gradle.startParameter.projectProperties)

You will get clue.

What do &lt; and &gt; stand for?

Others have noted the correct answer, but have not clearly explained the all-important reason:

  • why do we need this?

What do < and > stand for?

  • &lt; stands for the < sign. Just remember: lt == less than
  • &gt; stands for the > Just remember: gt == greater than

Why can’t we simply use the < and > characters in HTML?

  • This is because the > and < characters are ‘reserved’ characters in HTML.
  • HTML is a mark up language: The < and > are used to denote the starting and ending of different elements: e.g. <h1> and not for the displaying of the greater than or less than symbols. But what if you wanted to actually display those symbols? You would simply use &lt; and &gt; and the browser will know exactly how to display it.

pandas get rows which are NOT in other dataframe

a bit late, but it might be worth checking the "indicator" parameter of pd.merge.

See this other question for an example: Compare PandaS DataFrames and return rows that are missing from the first one

NULL values inside NOT IN clause

It may be concluded from answers here that NOT IN (subquery) doesn't handle nulls correctly and should be avoided in favour of NOT EXISTS. However, such a conclusion may be premature. In the following scenario, credited to Chris Date (Database Programming and Design, Vol 2 No 9, September 1989), it is NOT IN that handles nulls correctly and returns the correct result, rather than NOT EXISTS.

Consider a table sp to represent suppliers (sno) who are known to supply parts (pno) in quantity (qty). The table currently holds the following values:

      VALUES ('S1', 'P1', NULL), 
             ('S2', 'P1', 200),
             ('S3', 'P1', 1000)

Note that quantity is nullable i.e. to be able to record the fact a supplier is known to supply parts even if it is not known in what quantity.

The task is to find the suppliers who are known supply part number 'P1' but not in quantities of 1000.

The following uses NOT IN to correctly identify supplier 'S2' only:

WITH sp AS 
     ( SELECT * 
         FROM ( VALUES ( 'S1', 'P1', NULL ), 
                       ( 'S2', 'P1', 200 ),
                       ( 'S3', 'P1', 1000 ) )
              AS T ( sno, pno, qty )
     )
SELECT DISTINCT spx.sno
  FROM sp spx
 WHERE spx.pno = 'P1'
       AND 1000 NOT IN (
                        SELECT spy.qty
                          FROM sp spy
                         WHERE spy.sno = spx.sno
                               AND spy.pno = 'P1'
                       );

However, the below query uses the same general structure but with NOT EXISTS but incorrectly includes supplier 'S1' in the result (i.e. for which the quantity is null):

WITH sp AS 
     ( SELECT * 
         FROM ( VALUES ( 'S1', 'P1', NULL ), 
                       ( 'S2', 'P1', 200 ),
                       ( 'S3', 'P1', 1000 ) )
              AS T ( sno, pno, qty )
     )
SELECT DISTINCT spx.sno
  FROM sp spx
 WHERE spx.pno = 'P1'
       AND NOT EXISTS (
                       SELECT *
                         FROM sp spy
                        WHERE spy.sno = spx.sno
                              AND spy.pno = 'P1'
                              AND spy.qty = 1000
                      );

So NOT EXISTS is not the silver bullet it may have appeared!

Of course, source of the problem is the presence of nulls, therefore the 'real' solution is to eliminate those nulls.

This can be achieved (among other possible designs) using two tables:

  • sp suppliers known to supply parts
  • spq suppliers known to supply parts in known quantities

noting there should probably be a foreign key constraint where spq references sp.

The result can then be obtained using the 'minus' relational operator (being the EXCEPT keyword in Standard SQL) e.g.

WITH sp AS 
     ( SELECT * 
         FROM ( VALUES ( 'S1', 'P1' ), 
                       ( 'S2', 'P1' ),
                       ( 'S3', 'P1' ) )
              AS T ( sno, pno )
     ),
     spq AS 
     ( SELECT * 
         FROM ( VALUES ( 'S2', 'P1', 200 ),
                       ( 'S3', 'P1', 1000 ) )
              AS T ( sno, pno, qty )
     )
SELECT sno
  FROM spq
 WHERE pno = 'P1'
EXCEPT 
SELECT sno
  FROM spq
 WHERE pno = 'P1'
       AND qty = 1000;

Java 256-bit AES Password-Based Encryption

Consider using Encryptor4j of which I am the author.

First make sure you have Unlimited Strength Jurisdiction Policy files installed before your proceed so that you can use 256-bit AES keys.

Then do the following:

String password = "mysupersecretpassword"; 
Key key = KeyFactory.AES.keyFromPassword(password.toCharArray());
Encryptor encryptor = new Encryptor(key, "AES/CBC/PKCS7Padding", 16);

You can now use the encryptor to encrypt your message. You can also perform streaming encryption if you'd like. It automatically generates and prepends a secure IV for your convenience.

If it's a file that you wish to compress take a look at this answer Encrypting a large file with AES using JAVA for an even simpler approach.

Produce a random number in a range using C#

Try below code.

Random rnd = new Random();
int month = rnd.Next(1, 13); // creates a number between 1 and 12
int dice = rnd.Next(1, 7); // creates a number between 1 and 6
int card = rnd.Next(52); // creates a number between 0 and 51

How many threads can a Java VM support?

The absolute theoretical maximum is generally a process's user address space divided by the thread stack size (though in reality, if all your memory is reserved for thread stacks, you won't have a working program...).

So under 32-bit Windows, for example, where each process has a user address space of 2GB, giving each thread a 128K stack size, you'd expect an absolute maximum of 16384 threads (=2*1024*1024 / 128). In practice, I find I can start up about 13,000 under XP.

Then, I think you're essentially into whether (a) you can manage juggling that many threads in your code and not do obviously silly things (such as making them all wait on the same object then calling notifyAll()...), and (b) whether the operating system can. In principle, the answer to (b) is "yes" if the answer to (a) is also "yes".

Incidentally, you can specify the stack size in the constructor of the Thread; you don't need to (and probably shouldn't) mess about with VM parameters for this.

Calculating distance between two points (Latitude, Longitude)

It looks like Microsoft invaded brains of all other respondents and made them write as complicated solutions as possible. Here is the simplest way without any additional functions/declare statements:

SELECT geography::Point(LATITUDE_1, LONGITUDE_1, 4326).STDistance(geography::Point(LATITUDE_2, LONGITUDE_2, 4326))

Simply substitute your data instead of LATITUDE_1, LONGITUDE_1, LATITUDE_2, LONGITUDE_2 e.g.:

SELECT geography::Point(53.429108, -2.500953, 4326).STDistance(geography::Point(c.Latitude, c.Longitude, 4326))
from coordinates c

What is the javascript filename naming convention?

I generally prefer hyphens with lower case, but one thing not yet mentioned is that sometimes it's nice to have the file name exactly match the name of a single module or instantiable function contained within.

For example, I have a revealing module declared with var knockoutUtilityModule = function() {...} within its own file named knockoutUtilityModule.js, although objectively I prefer knockout-utility-module.js.

Similarly, since I'm using a bundling mechanism to combine scripts, I've taken to defining instantiable functions (templated view models etc) each in their own file, C# style, for maintainability. For example, ProductDescriptorViewModel lives on its own inside ProductDescriptorViewModel.js (I use upper case for instantiable functions).

Redirect website after certain amount of time

Use this simple javascript code to redirect page to another page using specific interval of time...

Please add this code into your web site page, which is you want to redirect :

<script type="text/javascript">
(function(){
   setTimeout(function(){
     window.location="http://brightwaay.com/";
   },3000); /* 1000 = 1 second*/
})();
</script>

Cannot resolve symbol 'AppCompatActivity'

Try this. In Android Studio, after putting the dependency in build.gradle. Go to Build --> Clean Project.

It worked for me.

What is the difference between a framework and a library?

Library:

It is just a collection of routines (functional programming) or class definitions(object oriented programming). The reason behind is simply code reuse, i.e. get the code that has already been written by other developers. The classes or routines normally define specific operations in a domain specific area. For example, there are some libraries of mathematics which can let developer just call the function without redo the implementation of how an algorithm works.

Framework:

In framework, all the control flow is already there, and there are a bunch of predefined white spots that we should fill out with our code. A framework is normally more complex. It defines a skeleton where the application defines its own features to fill out the skeleton. In this way, your code will be called by the framework when appropriately. The benefit is that developers do not need to worry about if a design is good or not, but just about implementing domain specific functions.

Library,Framework and your Code image representation:

Library,Framework and your Code image relation

KeyDifference:

The key difference between a library and a framework is “Inversion of Control”. When you call a method from a library, you are in control. But with a framework, the control is inverted: the framework calls you. Source.

Relation:

Both of them defined API, which is used for programmers to use. To put those together, we can think of a library as a certain function of an application, a framework as the skeleton of the application, and an API is connector to put those together. A typical development process normally starts with a framework, and fill out functions defined in libraries through API.

Determining image file size + dimensions via Javascript?

You can get the dimensions using getElement(...).width and ...height.

Since JavaScript can't access anything on the local disk for security reasons, you can't examine local files. This is also true for files in the browser's cache.

You really need a server which can process AJAX requests. On that server, install a service that downloads the image and saves the data stream in a dummy output which just counts the bytes. Note that you can't always rely on the Content-length header field since the image data might be encoded. Otherwise, it would be enough to send a HTTP HEAD request.

Border around each cell in a range

Here's another way

Sub testborder()

    Dim rRng As Range

    Set rRng = Sheet1.Range("B2:D5")

    'Clear existing
    rRng.Borders.LineStyle = xlNone

    'Apply new borders
    rRng.BorderAround xlContinuous
    rRng.Borders(xlInsideHorizontal).LineStyle = xlContinuous
    rRng.Borders(xlInsideVertical).LineStyle = xlContinuous

End Sub

How to check heap usage of a running JVM from the command line?

All procedure at once. Based on @Till Schäfer answer.

In KB...

jstat -gc $(ps axf | egrep -i "*/bin/java *" | egrep -v grep | awk '{print $1}') | tail -n 1 | awk '{split($0,a," "); sum=(a[3]+a[4]+a[6]+a[8]+a[10]); printf("%.2f KB\n",sum)}'

In MB...

jstat -gc $(ps axf | egrep -i "*/bin/java *" | egrep -v grep | awk '{print $1}') | tail -n 1 | awk '{split($0,a," "); sum=(a[3]+a[4]+a[6]+a[8]+a[10])/1024; printf("%.2f MB\n",sum)}'

"Awk sum" reference:

 a[1] - S0C
 a[2] - S1C
 a[3] - S0U
 a[4] - S1U
 a[5] - EC
 a[6] - EU
 a[7] - OC
 a[8] - OU
 a[9] - PC
a[10] - PU
a[11] - YGC
a[12] - YGCT
a[13] - FGC
a[14] - FGCT
a[15] - GCT

Used for "Awk sum":

a[3] -- (S0U) Survivor space 0 utilization (KB).
a[4] -- (S1U) Survivor space 1 utilization (KB).
a[6] -- (EU) Eden space utilization (KB).
a[8] -- (OU) Old space utilization (KB).
a[10] - (PU) Permanent space utilization (KB).

[Ref.: https://docs.oracle.com/javase/7/docs/technotes/tools/share/jstat.html ]

Thanks!

NOTE: Works to OpenJDK!

FURTHER QUESTION: Wrong information?

If you check memory usage with the ps command, you will see that the java process consumes much more...

ps -eo size,pid,user,command --sort -size | egrep -i "*/bin/java *" | egrep -v grep | awk '{ hr=$1/1024 ; printf("%.2f MB ",hr) } { for ( x=4 ; x<=NF ; x++ ) { printf("%s ",$x) } print "" }' | cut -d "" -f2 | cut -d "-" -f1

UPDATE (2021-02-16):

According to the reference below (and @Till Schäfer comment) "ps can show total reserved memory from OS" (adapted) and "jstat can show used space of heap and stack" (adapted). So, we see a difference between what is pointed out by the ps command and the jstat command.

According to our understanding, the most "realistic" information would be the ps output since we will have an effective response of how much of the system's memory is compromised. The command jstat serves for a more detailed analysis regarding the java performance in the consumption of reserved memory from OS.

[Ref.: http://www.openkb.info/2014/06/how-to-check-java-memory-usage.html ]

Using <style> tags in the <body> with other HTML

Because this is HTML is not valid does not have any affect on the outcome ... it just means that the HTML does adhere to the standard (merely for organizational purposes). For the sake of being valid it could have been written this way:

<html>
<head>
<style type="text/css">
  p.first {color:blue}
  p.second {color:green}
</style>
</head>
<body>
<p class="first" style="color:green;">Hello World</p>
<p class="second" style="color:blue;">Hello World</p>

My guess is that the browser applies the last style it comes across.

Python handling socket.error: [Errno 104] Connection reset by peer

You can try to add some time.sleep calls to your code.

It seems like the server side limits the amount of requests per timeunit (hour, day, second) as a security issue. You need to guess how many (maybe using another script with a counter?) and adjust your script to not surpass this limit.

In order to avoid your code from crashing, try to catch this error with try .. except around the urllib2 calls.

Convert seconds to Hour:Minute:Second

This is a pretty way to do that:

function time_converter($sec_time, $format='h:m:s'){
      $hour = intval($sec_time / 3600) >= 10 ? intval($sec_time / 3600) : '0'.intval($sec_time / 3600);
      $minute = intval(($sec_time % 3600) / 60) >= 10 ? intval(($sec_time % 3600) / 60) : '0'.intval(($sec_time % 3600) / 60);
      $sec = intval(($sec_time % 3600) % 60)  >= 10 ? intval(($sec_time % 3600) % 60) : '0'.intval(($sec_time % 3600) % 60);

      $format = str_replace('h', $hour, $format);
      $format = str_replace('m', $minute, $format);
      $format = str_replace('s', $sec, $format);

      return $format;
    }

log4j configuration via JVM argument(s)?

Do you have a log4j configuration file ? Just reference it using

-Dlog4j.configuration={path to file}

where {path to file} should be prefixed with file:

Edit: If you are working with log4j2, you need to use

-Dlog4j.configurationFile={path to file}

Taken from answer https://stackoverflow.com/a/34001970/552525

Is there an alternative to string.Replace that is case-insensitive?

Seems like string.Replace should have an overload that takes a StringComparison argument. Since it doesn't, you could try something like this:

public static string ReplaceString(string str, string oldValue, string newValue, StringComparison comparison)
{
    StringBuilder sb = new StringBuilder();

    int previousIndex = 0;
    int index = str.IndexOf(oldValue, comparison);
    while (index != -1)
    {
        sb.Append(str.Substring(previousIndex, index - previousIndex));
        sb.Append(newValue);
        index += oldValue.Length;

        previousIndex = index;
        index = str.IndexOf(oldValue, index, comparison);
    }
    sb.Append(str.Substring(previousIndex));

    return sb.ToString();
}

Android Completely transparent Status Bar?

This is only for API Level >= 21. It works for me. Here is my code (Kotlin)

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        findViewById<View>(android.R.id.content).systemUiVisibility =
                View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
}

Is it possible to program Android to act as physical USB keyboard?

You have to establish some kind of connection to do that android-out-of-the-box, like via tcp/ip and adb, so no not w/o installing at least adb and a listener on the computer.

But if you have an activity that sends the hardware keyboard like data via usb then why not? Won't be easy i guess. At this point the usuas forum answer comes right away: "Why don't you change your plans and ...." :)

find without recursion

If you look for POSIX compliant solution:

cd DirsRoot && find . -type f -print -o -name . -o -prune

-maxdepth is not POSIX compliant option.

Accept function as parameter in PHP

Tested for PHP 5.3

As i see here, Anonymous Function could help you: http://php.net/manual/en/functions.anonymous.php

What you'll probably need and it's not said before it's how to pass a function without wrapping it inside a on-the-fly-created function. As you'll see later, you'll need to pass the function's name written in a string as a parameter, check its "callability" and then call it.

The function to do check:

if( is_callable( $string_function_name ) ){
    /*perform the call*/
}

Then, to call it, use this piece of code (if you need parameters also, put them on an array), seen at : http://php.net/manual/en/function.call-user-func.php

call_user_func_array( "string_holding_the_name_of_your_function", $arrayOfParameters );

as it follows (in a similar, parameterless, way):

    function funToBeCalled(){
        print("----------------------i'm here");
    }
    function wrapCaller($fun){
        if( is_callable($fun)){
            print("called");
            call_user_func($fun);
        }else{
            print($fun." not called");
        }
    }

    wrapCaller("funToBeCalled");
    wrapCaller("cannot call me");

Here's a class explaining how to do something similar :

<?php
class HolderValuesOrFunctionsAsString{
    private $functions = array();
    private $vars = array();

    function __set($name,$data){
        if(is_callable($data))
            $this->functions[$name] = $data;
        else
            $this->vars[$name] = $data;
    }

    function __get($name){
        $t = $this->vars[$name];
        if(isset($t))
            return $t;
        else{
            $t = $this->$functions[$name];
            if( isset($t))
                return $t;
        }
    }

    function __call($method,$args=null){
        $fun = $this->functions[$method];
        if(isset($fun)){
            call_user_func_array($fun,$args);
        } else {
            // error out
            print("ERROR: Funciton not found: ". $method);
        }
    }
}
?>

and an example of usage

<?php
    /*create a sample function*/
    function sayHello($some = "all"){
    ?>
         <br>hello to <?=$some?><br>
    <?php
    }

    $obj = new HolderValuesOrFunctionsAsString;

    /*do the assignement*/
    $obj->justPrintSomething = 'sayHello'; /*note that the given
        "sayHello" it's a string ! */

    /*now call it*/
    $obj->justPrintSomething(); /*will print: "hello to all" and
        a break-line, for html purpose*/

    /*if the string assigned is not denoting a defined method
         , it's treat as a simple value*/
    $obj->justPrintSomething = 'thisFunctionJustNotExistsLOL';

    echo $obj->justPrintSomething; /*what do you expect to print?
        just that string*/
    /*N.B.: "justPrintSomething" is treated as a variable now!
        as the __set 's override specify"*/

    /*after the assignement, the what is the function's destiny assigned before ? It still works, because it's held on a different array*/
     $obj->justPrintSomething("Jack Sparrow");


     /*You can use that "variable", ie "justPrintSomething", in both ways !! so you can call "justPrintSomething" passing itself as a parameter*/

     $obj->justPrintSomething( $obj->justPrintSomething );
         /*prints: "hello to thisFunctionJustNotExistsLOL" and a break-line*/

    /*in fact, "justPrintSomething" it's a name used to identify both
         a value (into the dictionary of values) or a function-name
         (into the dictionary of functions)*/
?>

Is there a way to have printf() properly print out an array (of floats, say)?

You need to go for a loop:

for (int i = 0; i < sizeof(foo) / sizeof(float); ++i)
   printf("%f", foo[i]);
printf("\n");

C++ auto keyword. Why is it magic?

For variables, specifies that the type of the variable that is being declared will be automatically deduced from its initializer. For functions, specifies that the return type is a trailing return type or will be deduced from its return statements (since C++14).

Syntax

auto variable initializer   (1) (since C++11)

auto function -> return type    (2) (since C++11)

auto function   (3) (since C++14)

decltype(auto) variable initializer (4) (since C++14)

decltype(auto) function (5) (since C++14)

auto :: (6) (concepts TS)

cv(optional) auto ref(optional) parameter   (7) (since C++14)

Explanation

1) When declaring variables in block scope, in namespace scope, in initialization statements of for loops, etc., the keyword auto may be used as the type specifier. Once the type of the initializer has been determined, the compiler determines the type that will replace the keyword auto using the rules for template argument deduction from a function call (see template argument deduction#Other contexts for details). The keyword auto may be accompanied by modifiers, such as const or &, which will participate in the type deduction. For example, given const auto& i = expr;, the type of i is exactly the type of the argument u in an imaginary template template<class U> void f(const U& u) if the function call f(expr) was compiled. Therefore, auto&& may be deduced either as an lvalue reference or rvalue reference according to the initializer, which is used in range-based for loop. If auto is used to declare multiple variables, the deduced types must match. For example, the declaration auto i = 0, d = 0.0; is ill-formed, while the declaration auto i = 0, *p = &i; is well-formed and the auto is deduced as int.

2) In a function declaration that uses the trailing return type syntax, the keyword auto does not perform automatic type detection. It only serves as a part of the syntax.

3) In a function declaration that does not use the trailing return type syntax, the keyword auto indicates that the return type will be deduced from the operand of its return statement using the rules for template argument deduction.

4) If the declared type of the variable is decltype(auto), the keyword auto is replaced with the expression (or expression list) of its initializer, and the actual type is deduced using the rules for decltype.

5) If the return type of the function is declared decltype(auto), the keyword auto is replaced with the operand of its return statement, and the actual return type is deduced using the rules for decltype.

6) A nested-name-specifier of the form auto:: is a placeholder that is replaced by a class or enumeration type following the rules for constrained type placeholder deduction.

7) A parameter declaration in a lambda expression. (since C++14) A function parameter declaration. (concepts TS)

Notes Until C++11, auto had the semantic of a storage duration specifier. Mixing auto variables and functions in one declaration, as in auto f() -> int, i = 0; is not allowed.

For more info : http://en.cppreference.com/w/cpp/language/auto

How to get current time and date in C++?

I found this link pretty useful for my implementation: C++ Date and Time

Here's the code I use in my implementation, to get a clear "YYYYMMDD HHMMSS" output format. The param in is for switching between UTC and local time. You can easily modify my code to suite your need.

#include <iostream>
#include <ctime>

using namespace std;

/**
 * This function gets the current date time
 * @param useLocalTime true if want to use local time, default to false (UTC)
 * @return current datetime in the format of "YYYYMMDD HHMMSS"
 */

string getCurrentDateTime(bool useLocalTime) {
    stringstream currentDateTime;
    // current date/time based on current system
    time_t ttNow = time(0);
    tm * ptmNow;

    if (useLocalTime)
        ptmNow = localtime(&ttNow);
    else
        ptmNow = gmtime(&ttNow);

    currentDateTime << 1900 + ptmNow->tm_year;

    //month
    if (ptmNow->tm_mon < 9)
        //Fill in the leading 0 if less than 10
        currentDateTime << "0" << 1 + ptmNow->tm_mon;
    else
        currentDateTime << (1 + ptmNow->tm_mon);

    //day
    if (ptmNow->tm_mday < 10)
        currentDateTime << "0" << ptmNow->tm_mday << " ";
    else
        currentDateTime <<  ptmNow->tm_mday << " ";

    //hour
    if (ptmNow->tm_hour < 10)
        currentDateTime << "0" << ptmNow->tm_hour;
    else
        currentDateTime << ptmNow->tm_hour;

    //min
    if (ptmNow->tm_min < 10)
        currentDateTime << "0" << ptmNow->tm_min;
    else
        currentDateTime << ptmNow->tm_min;

    //sec
    if (ptmNow->tm_sec < 10)
        currentDateTime << "0" << ptmNow->tm_sec;
    else
        currentDateTime << ptmNow->tm_sec;


    return currentDateTime.str();
}

Output (UTC, EST):

20161123 000454
20161122 190454

require(vendor/autoload.php): failed to open stream

Proper autoload.php configuration:

A) Quick answer:

Your autoload.php path is wrong. ie. C:\Windows\SysWOW64\vendor\autoload.php To date: you need to change it to: C:\Users\<Windows User Name>\vendor\autoload.php


B) Steps with example: We will take facebook/php-graph-sdk as an example; change to Package Name as needed.

  1. Install composer.exe
  2. Open CMD Prompt. + R + type CMD
  3. Run This command: composer require facebook/graph-sdk
  4. Include path in your PHP page: require_once 'C:\Users\<Windows User Name>\vendor\autoload.php';
  5. Define configuration Secrets and Access Token for your package...etc.
  6. Happy codinig.

C) Further details:

Installing composer on windows will set this default path for your pacakges; you can find them there and include the autoloader path:

C:\Users\<Windows User Name>\vendor

For the same question you asked; the answer was this path for WAMP Server 64 BIT for Windows.

Then simply in your PHP Application change this:

require_once __DIR__ . '/vendor/autoload.php'; 

To:

require_once 'C:\Users\<Windows User Name>\vendor\autoload.php'; 

Find your windows username under C:\Users\

Before all this, as pointed before in B) , you need to run this command:

composer require <package name>

for facebook php SDK for example:

composer require facebook/graph-sdk

Thank you for asking this question; appreciated as it helped me fix similar issue and ended writing this simple tutorial.

Change the mouse pointer using JavaScript

document.body.style.cursor = 'cursorurl';

NameError: name 'self' is not defined

If you have arrived here via google, please make sure to check that you have given self as the first parameter to a class function. Especially if you try to reference values for that object instance inside the class function.

def foo():
    print(self.bar)

>NameError: name 'self' is not defined

def foo(self):
    print(self.bar)

Not class selector in jQuery

You can use the :not filter selector:

$('foo:not(".someClass")')

Or not() method:

$('foo').not(".someClass")

More Info:

Reactive forms - disabled attribute

I tried these in angular 7. It worked successfully.

this.form.controls['fromField'].reset();
if(condition){
      this.form.controls['fromField'].enable();
}
else{
      this.form.controls['fromField'].disable();
}

How do I insert values into a Map<K, V>?

The syntax is

data.put("John","Taxi driver");

ORA-03113: end-of-file on communication channel after long inactivity in ASP.Net app

ORA-03113: end-of-file on communication channel

Is the database letting you know that the network connection is no more. This could be because:

  1. A network issue - faulty connection, or firewall issue
  2. The server process on the database that is servicing you died unexpectedly.

For 1) (firewall) search tahiti.oracle.com for SQLNET.EXPIRE_TIME. This is a sqlnet.ora parameter that will regularly send a network packet at a configurable interval ie: setting this will make the firewall believe that the connection is live.

For 1) (network) speak to your network admin (connection could be unreliable)

For 2) Check the alert.log for errors. If the server process failed there will be an error message. Also a trace file will have been written to enable support to identify the issue. The error message will reference the trace file.

Support issues can be raised at metalink.oracle.com with a suitable Customer Service Identifier (CSI)

<img>: Unsafe value used in a resource URL context

Pipe

// Angular
import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer, SafeHtml, SafeStyle, SafeScript, SafeUrl, SafeResourceUrl } from '@angular/platform-browser';

/**
 * Sanitize HTML
 */
@Pipe({
  name: 'safe'
})
export class SafePipe implements PipeTransform {
  /**
   * Pipe Constructor
   *
   * @param _sanitizer: DomSanitezer
   */
  // tslint:disable-next-line
  constructor(protected _sanitizer: DomSanitizer) {
  }

  /**
   * Transform
   *
   * @param value: string
   * @param type: string
   */
  transform(value: string, type: string): SafeHtml | SafeStyle | SafeScript | SafeUrl | SafeResourceUrl {
    switch (type) {
      case 'html':
        return this._sanitizer.bypassSecurityTrustHtml(value);
      case 'style':
        return this._sanitizer.bypassSecurityTrustStyle(value);
      case 'script':
        return this._sanitizer.bypassSecurityTrustScript(value);
      case 'url':
        return this._sanitizer.bypassSecurityTrustUrl(value);
      case 'resourceUrl':
        return this._sanitizer.bypassSecurityTrustResourceUrl(value);
      default:
        return this._sanitizer.bypassSecurityTrustHtml(value);
    }
  }
}

Template

{{ data.url | safe:'url' }}

That's it!

Note: You shouldn't need it but here is the component use of the pipe
  // Public properties
  itsSafe: SafeHtml;

  // Private properties
  private safePipe: SafePipe = new SafePipe(this.domSanitizer);

  /**
   * Component constructor
   *
   * @param safePipe: SafeHtml
   * @param domSanitizer: DomSanitizer
   */
  constructor(private safePipe: SafePipe, private domSanitizer: DomSanitizer) {
  }

  /**
   * On init
   */
  ngOnInit(): void {
    this.itsSafe = this.safePipe.transform('<h1>Hi</h1>', 'html');
  }

Checking if a SQL Server login already exists

This works on SQL Server 2000.

use master
select count(*) From sysxlogins WHERE NAME = 'myUsername'

on SQL 2005, change the 2nd line to

select count(*) From syslogins WHERE NAME = 'myUsername'

I'm not sure about SQL 2008, but I'm guessing that it will be the same as SQL 2005 and if not, this should give you an idea of where t start looking.

Undo a git stash

git stash list to list your stashed changes.

git stash show to see what n is in the below commands.

git stash apply to apply the most recent stash.

git stash apply stash@{n} to apply an older stash.

https://git-scm.com/book/en/v2/Git-Tools-Stashing-and-Cleaning

Select all occurrences of selected word in VSCode

In my MacOS case for some reason Cmd+Shift+L is not working while pressing the short cut on the keyboard (although it work just fine while clicking on this option in menu: Selection -> Select All Occurences). So for me pressing Cmd+FN+F2 did the trick (FN is for enabling "F2" obviously).

Btw, if you forget this shortcut just do right-click on the selection and see "Change All Occurrences" option

Max length UITextField

In Swift 4

10 Characters limit for text field and allow to delete(backspace)

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        if textField ==  userNameFTF{
            let char = string.cString(using: String.Encoding.utf8)
            let isBackSpace = strcmp(char, "\\b")
            if isBackSpace == -92 {
                return true
            }
            return textField.text!.count <= 9
        }
        return true
    }

Filter Java Stream to 1 and only 1 element

For the sake of completeness, here is the ‘one-liner’ corresponding to @prunge’s excellent answer:

User user1 = users.stream()
        .filter(user -> user.getId() == 1)
        .reduce((a, b) -> {
            throw new IllegalStateException("Multiple elements: " + a + ", " + b);
        })
        .get();

This obtains the sole matching element from the stream, throwing

  • NoSuchElementException in case the stream is empty, or
  • IllegalStateException in case the stream contains more than one matching element.

A variation of this approach avoids throwing an exception early and instead represents the result as an Optional containing either the sole element, or nothing (empty) if there are zero or multiple elements:

Optional<User> user1 = users.stream()
        .filter(user -> user.getId() == 1)
        .collect(Collectors.reducing((a, b) -> null));

How to build a query string for a URL in C#?

Add this class to your project

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

public class QueryStringBuilder
{
    private readonly List<KeyValuePair<string, object>> _list;

    public QueryStringBuilder()
    {
        _list = new List<KeyValuePair<string, object>>();
    }

    public void Add(string name, object value)
    {
        _list.Add(new KeyValuePair<string, object>(name, value));
    }

    public override string ToString()
    {
        return String.Join("&", _list.Select(kvp => String.Concat(Uri.EscapeDataString(kvp.Key), "=", Uri.EscapeDataString(kvp.Value.ToString()))));
    }
}

And use it like this:

var actual = new QueryStringBuilder {
    {"foo", 123},
    {"bar", "val31"},
    {"bar", "val32"}
};

actual.Add("a+b", "c+d");

actual.ToString(); // "foo=123&bar=val31&bar=val32&a%2bb=c%2bd"

Clearing _POST array fully

You can use a combination of both unset() and initialization:

unset($_POST);
$_POST = array();

Or in a single statement:

unset($_POST) ? $_POST = array() : $_POST = array();

But what is the reason you want to do this?

Error loading MySQLdb Module 'Did you install mysqlclient or MySQL-python?'

Installing mysqlclient using anaconda is pretty simple and straight forward.

conda install -c bioconda mysqlclient

and then, install pymysql using pip.

pip install pymysql

happy learning..

How can I check for existence of element in std::vector, in one line?

Unsorted vector:

if (std::find(v.begin(), v.end(),value)!=v.end())
    ...

Sorted vector:

if (std::binary_search(v.begin(), v.end(), value)
   ...

P.S. may need to include <algorithm> header

Adding sheets to end of workbook in Excel (normal method not working?)

mainWB.Sheets.Add(After:=Sheets(Sheets.Count)).Name = new_sheet_name 

should probably be

mainWB.Sheets.Add(After:=mainWB.Sheets(mainWB.Sheets.Count)).Name = new_sheet_name 

HTML Drag And Drop On Mobile Devices

I needed to create a drag and drop + rotation that works on desktop, mobile, tablet including windows phone. The last one made it more complicated (mspointer vs. touch events).

The solution came from The great Greensock library

It took some jumping through hoops to make the same object draggable and rotatable but it works perfectly

How to pass a datetime parameter?

This is a solution and a model for possible solutions. Use Moment.js in your client to format dates, convert to unix time.

 $scope.startDate.unix()

Setup your route parameters to be long.

[Route("{startDate:long?}")]
public async Task<object[]> Get(long? startDate)
{
    DateTime? sDate = new DateTime();

        if (startDate != null)
        {
            sDate = new DateTime().FromUnixTime(startDate.Value); 
        }
        else
        {
            sDate = null;
        }
         ... your code here!
  }

Create an extension method for Unix time. Unix DateTime Method

Configuring diff tool with .gitconfig

An additional way to do that (from the command line):

git config --global diff.tool tkdiff
git config --global merge.tool tkdiff
git config --global --add difftool.prompt false

The first two lines will set the difftool and mergetool to tkdiff- change that according to your preferences. The third line disables the annoying prompt so whenever you hit git difftool it will automatically launch the difftool.

multiprocessing.Pool: When to use apply, apply_async or map?

Here is an overview in a table format in order to show the differences between Pool.apply, Pool.apply_async, Pool.map and Pool.map_async. When choosing one, you have to take multi-args, concurrency, blocking, and ordering into account:

                  | Multi-args   Concurrence    Blocking     Ordered-results
---------------------------------------------------------------------
Pool.map          | no           yes            yes          yes
Pool.map_async    | no           yes            no           yes
Pool.apply        | yes          no             yes          no
Pool.apply_async  | yes          yes            no           no
Pool.starmap      | yes          yes            yes          yes
Pool.starmap_async| yes          yes            no           no

Notes:

  • Pool.imap and Pool.imap_async – lazier version of map and map_async.

  • Pool.starmap method, very much similar to map method besides it acceptance of multiple arguments.

  • Async methods submit all the processes at once and retrieve the results once they are finished. Use get method to obtain the results.

  • Pool.map(or Pool.apply)methods are very much similar to Python built-in map(or apply). They block the main process until all the processes complete and return the result.

Examples:

map

Is called for a list of jobs in one time

results = pool.map(func, [1, 2, 3])

apply

Can only be called for one job

for x, y in [[1, 1], [2, 2]]:
    results.append(pool.apply(func, (x, y)))

def collect_result(result):
    results.append(result)

map_async

Is called for a list of jobs in one time

pool.map_async(func, jobs, callback=collect_result)

apply_async

Can only be called for one job and executes a job in the background in parallel

for x, y in [[1, 1], [2, 2]]:
    pool.apply_async(worker, (x, y), callback=collect_result)

starmap

Is a variant of pool.map which support multiple arguments

pool.starmap(func, [(1, 1), (2, 1), (3, 1)])

starmap_async

A combination of starmap() and map_async() that iterates over iterable of iterables and calls func with the iterables unpacked. Returns a result object.

pool.starmap_async(calculate_worker, [(1, 1), (2, 1), (3, 1)], callback=collect_result)

Reference:

Find complete documentation here: https://docs.python.org/3/library/multiprocessing.html

How to tell which disk Windows Used to Boot

You can use WMI to figure this out. The Win32_BootConfiguration class will tell you both the logical drive and the physical device from which Windows boots. Specifically, the Caption property will tell you which device you're booting from.

For example, in powershell, just type gwmi Win32_BootConfiguration to get your answer.

javascript compare strings without being case sensitive

Another method using a regular expression (this is more correct than Zachary's answer):

var string1 = 'someText',
    string2 = 'SometexT',
    regex = new RegExp('^' + string1 + '$', 'i');

if (regex.test(string2)) {
    return true;
}

RegExp.test() will return true or false.

Also, adding the '^' (signifying the start of the string) to the beginning and '$' (signifying the end of the string) to the end make sure that your regular expression will match only if 'sometext' is the only text in stringToTest. If you're looking for text that contains the regular expression, it's ok to leave those off.

It might just be easier to use the string.toLowerCase() method.

So... regular expressions are powerful, but you should only use them if you understand how they work. Unexpected things can happen when you use something you don't understand.

There are tons of regular expression 'tutorials', but most appear to be trying to push a certain product. Here's what looks like a decent tutorial... granted, it's written for using php, but otherwise, it appears to be a nice beginner's tutorial: http://weblogtoolscollection.com/regex/regex.php

This appears to be a good tool to test regular expressions: http://gskinner.com/RegExr/

How to import a SQL Server .bak file into MySQL?

I did not manage to find a way to do it directly.

Instead I imported the bak file into SQL Server 2008 Express, and then used MySQL Migration Toolkit.

Worked like a charm!

Reset all changes after last commit in git

How can I undo every change made to my directory after the last commit, including deleting added files, resetting modified files, and adding back deleted files?

  1. You can undo changes to tracked files with:

    git reset HEAD --hard
    
  2. You can remove untracked files with:

    git clean -f
    
  3. You can remove untracked files and directories with:

    git clean -fd
    

    but you can't undo change to untracked files.

  4. You can remove ignored and untracked files and directories

    git clean -fdx
    

    but you can't undo change to ignored files.

You can also set clean.requireForce to false:

git config --global --add clean.requireForce false

to avoid using -f (--force) when you use git clean.

R define dimensions of empty data frame

Would a dataframe of NAs work? something like:

data.frame(matrix(NA, nrow = 2, ncol = 3))

if you need to be more specific about the data type then may prefer: NA_integer_, NA_real_, NA_complex_, or NA_character_ instead of just NA which is logical

Something else that may be more specific that the NAs is:

data.frame(matrix(vector(mode = 'numeric',length = 6), nrow = 2, ncol = 3))

where the mode can be of any type. See ?vector

JavaScript: function returning an object

In JavaScript, most functions are both callable and instantiable: they have both a [[Call]] and [[Construct]] internal methods.

As callable objects, you can use parentheses to call them, optionally passing some arguments. As a result of the call, the function can return a value.

var player = makeGamePlayer("John Smith", 15, 3);

The code above calls function makeGamePlayer and stores the returned value in the variable player. In this case, you may want to define the function like this:

function makeGamePlayer(name, totalScore, gamesPlayed) {
  // Define desired object
  var obj = {
    name:  name,
    totalScore: totalScore,
    gamesPlayed: gamesPlayed
  };
  // Return it
  return obj;
}

Additionally, when you call a function you are also passing an additional argument under the hood, which determines the value of this inside the function. In the case above, since makeGamePlayer is not called as a method, the this value will be the global object in sloppy mode, or undefined in strict mode.

As constructors, you can use the new operator to instantiate them. This operator uses the [[Construct]] internal method (only available in constructors), which does something like this:

  1. Creates a new object which inherits from the .prototype of the constructor
  2. Calls the constructor passing this object as the this value
  3. It returns the value returned by the constructor if it's an object, or the object created at step 1 otherwise.
var player = new GamePlayer("John Smith", 15, 3);

The code above creates an instance of GamePlayer and stores the returned value in the variable player. In this case, you may want to define the function like this:

function GamePlayer(name,totalScore,gamesPlayed) {
  // `this` is the instance which is currently being created
  this.name =  name;
  this.totalScore = totalScore;
  this.gamesPlayed = gamesPlayed;
  // No need to return, but you can use `return this;` if you want
}

By convention, constructor names begin with an uppercase letter.

The advantage of using constructors is that the instances inherit from GamePlayer.prototype. Then, you can define properties there and make them available in all instances

How do you determine what technology a website is built on?

There is also W3Techs, which shows you much of that information.

How to include a PHP variable inside a MySQL statement

Here

$type='testing' //it's string

mysql_query("INSERT INTO contents (type, reporter, description) VALUES('$type', 'john', 'whatever')");//at that time u can use it(for string)


$type=12 //it's integer
mysql_query("INSERT INTO contents (type, reporter, description) VALUES($type, 'john', 'whatever')");//at that time u can use $type

How do I perform a Perl substitution on a string while keeping the original?

Another pre-5.14 solution: http://www.perlmonks.org/?node_id=346719 (see japhy's post)

As his approach uses map, it also works well for arrays, but requires cascading map to produce a temporary array (otherwise the original would be modified):

my @orig = ('this', 'this sucks', 'what is this?');
my @list = map { s/this/that/; $_ } map { $_ } @orig;
# @orig unmodified

Convert pyspark string to date format

The strptime() approach does not work for me. I get another cleaner solution, using cast:

from pyspark.sql.types import DateType
spark_df1 = spark_df.withColumn("record_date",spark_df['order_submitted_date'].cast(DateType()))
#below is the result
spark_df1.select('order_submitted_date','record_date').show(10,False)

+---------------------+-----------+
|order_submitted_date |record_date|
+---------------------+-----------+
|2015-08-19 12:54:16.0|2015-08-19 |
|2016-04-14 13:55:50.0|2016-04-14 |
|2013-10-11 18:23:36.0|2013-10-11 |
|2015-08-19 20:18:55.0|2015-08-19 |
|2015-08-20 12:07:40.0|2015-08-20 |
|2013-10-11 21:24:12.0|2013-10-11 |
|2013-10-11 23:29:28.0|2013-10-11 |
|2015-08-20 16:59:35.0|2015-08-20 |
|2015-08-20 17:32:03.0|2015-08-20 |
|2016-04-13 16:56:21.0|2016-04-13 |

jquery's append not working with svg element?

A much simpler way is to just generate your SVG into a string, create a wrapper HTML element and insert the svg string into the HTML element using $("#wrapperElement").html(svgString). This works just fine in Chrome and Firefox.

apache and httpd running but I can't see my website

Did you restart the server after you changed the config file?

Can you telnet to the server from a different machine?

Can you telnet to the server from the server itself?

telnet <ip address> 80

telnet localhost 80

Detect & Record Audio in Python

I believe the WAVE module does not support recording, just processing existing files. You might want to look at PyAudio for actually recording. WAV is about the world's simplest file format. In paInt16 you just get a signed integer representing a level, and closer to 0 is quieter. I can't remember if WAV files are high byte first or low byte, but something like this ought to work (sorry, I'm not really a python programmer:

from array import array

# you'll probably want to experiment on threshold
# depends how noisy the signal
threshold = 10 
max_value = 0

as_ints = array('h', data)
max_value = max(as_ints)
if max_value > threshold:
    # not silence

PyAudio code for recording kept for reference:

import pyaudio
import sys

chunk = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 44100
RECORD_SECONDS = 5

p = pyaudio.PyAudio()

stream = p.open(format=FORMAT,
                channels=CHANNELS, 
                rate=RATE, 
                input=True,
                output=True,
                frames_per_buffer=chunk)

print "* recording"
for i in range(0, 44100 / chunk * RECORD_SECONDS):
    data = stream.read(chunk)
    # check for silence here by comparing the level with 0 (or some threshold) for 
    # the contents of data.
    # then write data or not to a file

print "* done"

stream.stop_stream()
stream.close()
p.terminate()

Good examples of python-memcache (memcached) being used in Python?

It's fairly simple. You write values using keys and expiry times. You get values using keys. You can expire keys from the system.

Most clients follow the same rules. You can read the generic instructions and best practices on the memcached homepage.

If you really want to dig into it, I'd look at the source. Here's the header comment:

"""
client module for memcached (memory cache daemon)

Overview
========

See U{the MemCached homepage<http://www.danga.com/memcached>} for more about memcached.

Usage summary
=============

This should give you a feel for how this module operates::

    import memcache
    mc = memcache.Client(['127.0.0.1:11211'], debug=0)

    mc.set("some_key", "Some value")
    value = mc.get("some_key")

    mc.set("another_key", 3)
    mc.delete("another_key")

    mc.set("key", "1")   # note that the key used for incr/decr must be a string.
    mc.incr("key")
    mc.decr("key")

The standard way to use memcache with a database is like this::

    key = derive_key(obj)
    obj = mc.get(key)
    if not obj:
        obj = backend_api.get(...)
        mc.set(key, obj)

    # we now have obj, and future passes through this code
    # will use the object from the cache.

Detailed Documentation
======================

More detailed documentation is available in the L{Client} class.
"""

HTML table with horizontal scrolling (first column fixed)

How about:

_x000D_
_x000D_
table {_x000D_
  table-layout: fixed; _x000D_
  width: 100%;_x000D_
  *margin-left: -100px; /*ie7*/_x000D_
}_x000D_
td, th {_x000D_
  vertical-align: top;_x000D_
  border-top: 1px solid #ccc;_x000D_
  padding: 10px;_x000D_
  width: 100px;_x000D_
}_x000D_
.fix {_x000D_
  position: absolute;_x000D_
  *position: relative; /*ie7*/_x000D_
  margin-left: -100px;_x000D_
  width: 100px;_x000D_
}_x000D_
.outer {_x000D_
  position: relative;_x000D_
}_x000D_
.inner {_x000D_
  overflow-x: scroll;_x000D_
  overflow-y: visible;_x000D_
  width: 400px; _x000D_
  margin-left: 100px;_x000D_
}
_x000D_
<div class="outer">_x000D_
  <div class="inner">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <th class=fix></th>_x000D_
        <th>Col 1</th>_x000D_
        <th>Col 2</th>_x000D_
        <th>Col 3</th>_x000D_
        <th>Col 4</th>_x000D_
        <th class="fix">Col 5</th>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <th class=fix>Header A</th>_x000D_
        <td>col 1 - A</td>_x000D_
        <td>col 2 - A (WITH LONGER CONTENT)</td>_x000D_
        <td>col 3 - A</td>_x000D_
        <td>col 4 - A</td>_x000D_
        <td class=fix>col 5 - A</td>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <th class=fix>Header B</th>_x000D_
        <td>col 1 - B</td>_x000D_
        <td>col 2 - B</td>_x000D_
        <td>col 3 - B</td>_x000D_
        <td>col 4 - B</td>_x000D_
        <td class=fix>col 5 - B</td>_x000D_
      </tr>_x000D_
      <tr>_x000D_
        <th class=fix>Header C</th>_x000D_
        <td>col 1 - C</td>_x000D_
        <td>col 2 - C</td>_x000D_
        <td>col 3 - C</td>_x000D_
        <td>col 4 - C</td>_x000D_
        <td class=fix>col 5 - C</td>_x000D_
      </tr>_x000D_
    </table>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

You can test it out in this jsbin: http://jsbin.com/uxecel/4/edit

Software Design vs. Software Architecture

Architecture is more like integrating various functionalities of a System to achive one goal of the System as a whole, while design addresses each functional requirements.

For example, take example of MVVM, which is an architectural pattern. For notification functionality, MVVM uses observer Pattern, which in turn is a design pattern,

Actual meaning of 'shell=True' in subprocess

Executing programs through the shell means that all user input passed to the program is interpreted according to the syntax and semantic rules of the invoked shell. At best, this only causes inconvenience to the user, because the user has to obey these rules. For instance, paths containing special shell characters like quotation marks or blanks must be escaped. At worst, it causes security leaks, because the user can execute arbitrary programs.

shell=True is sometimes convenient to make use of specific shell features like word splitting or parameter expansion. However, if such a feature is required, make use of other modules are given to you (e.g. os.path.expandvars() for parameter expansion or shlex for word splitting). This means more work, but avoids other problems.

In short: Avoid shell=True by all means.