Programs & Examples On #Urlconf

Django URLs TypeError: view must be a callable or a list/tuple in the case of include()

Django 1.10 no longer allows you to specify views as a string (e.g. 'myapp.views.home') in your URL patterns.

The solution is to update your urls.py to include the view callable. This means that you have to import the view in your urls.py. If your URL patterns don't have names, then now is a good time to add one, because reversing with the dotted python path no longer works.

from django.conf.urls import include, url

from django.contrib.auth.views import login
from myapp.views import home, contact

urlpatterns = [
    url(r'^$', home, name='home'),
    url(r'^contact/$', contact, name='contact'),
    url(r'^login/$', login, name='login'),
]

If there are many views, then importing them individually can be inconvenient. An alternative is to import the views module from your app.

from django.conf.urls import include, url

from django.contrib.auth import views as auth_views
from myapp import views as myapp_views

urlpatterns = [
    url(r'^$', myapp_views.home, name='home'),
    url(r'^contact/$', myapp_views.contact, name='contact'),
    url(r'^login/$', auth_views.login, name='login'),
]

Note that we have used as myapp_views and as auth_views, which allows us to import the views.py from multiple apps without them clashing.

See the Django URL dispatcher docs for more information about urlpatterns.

Django: ImproperlyConfigured: The SECRET_KEY setting must not be empty

The reason why there are so many different answers is because the exception probably doesn't have anything to do with the SECRET_KEY. It is probably an earlier exception that is being swallowed. Turn on debugging using DEBUG=True to see the real exception.

Include CSS and Javascript in my django template

Refer django docs on static files.

In settings.py:

import os
CURRENT_PATH = os.path.abspath(os.path.dirname(__file__).decode('utf-8'))

MEDIA_ROOT = os.path.join(CURRENT_PATH, 'media')

MEDIA_URL = '/media/'

STATIC_ROOT = 'static/'

STATIC_URL = '/static/'

STATICFILES_DIRS = (
                    os.path.join(CURRENT_PATH, 'static'),
)

Then place your js and css files static folder in your project. Not in media folder.

In views.py:

from django.shortcuts import render_to_response, RequestContext

def view_name(request):
    #your stuff goes here
    return render_to_response('template.html', locals(), context_instance = RequestContext(request))

In template.html:

<link rel="stylesheet" type="text/css" href="{{ STATIC_URL }}css/style.css" />
<script type="text/javascript" src="{{ STATIC_URL }}js/jquery-1.8.3.min.js"></script>

In urls.py:

from django.conf import settings
urlpatterns += patterns('',
    url(r'^media/(?P<path>.*)$', 'django.views.static.serve', {'document_root': settings.MEDIA_ROOT, 'show_indexes': True}),
)

Project file structure can be found here in imgbin.

Setting DEBUG = False causes 500 Error

You might want to run python manage.py collectstatic after you set DEBUG = False and ALLOWED_HOSTS = ['127.0.0.1'] in settings.py. After these two steps my web application ran well in my local server even with DEBUG=False mode.

BTW I have these settings in settings.py.

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'whitenoise.middleware.WhiteNoiseMiddleware', # what i added
    'django.middleware.common.CommonMiddleware', # and so on...
]

STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage'

I assume maybe whitenoise setting has something to do with collectstatic command.

Django MEDIA_URL and MEDIA_ROOT

Please read the official Django DOC carefully and you will find the most fit answer.

The best and easist way to solve this is like below.

from django.conf import settings
from django.conf.urls.static import static

urlpatterns = patterns('',
    # ... the rest of your URLconf goes here ...
) + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

Purpose of __repr__ method?

Implement repr for every class you implement. There should be no excuse. Implement str for classes which you think readability is more important of non-ambiguity.

Refer this link: https://www.pythoncentral.io/what-is-the-difference-between-str-and-repr-in-python/

Are HTTP cookies port specific?

This is a big gray area in cookie SOP (Same Origin Policy).

Theoretically, you can specify port number in the domain and the cookie will not be shared. In practice, this doesn't work with several browsers and you will run into other issues. So this is only feasible if your sites are not for general public and you can control what browsers to use.

The better approach is to get 2 domain names for the same IP and not relying on port numbers for cookies.

How to avoid "cannot load such file -- utils/popen" from homebrew on OSX

After updating to El Capitan, /usr/local has root:wheel rights.

Change the rights back to the user using:

sudo chown -R $(whoami):admin /usr/local

and:

brew doctor && brew update

This helped me to get Homebrew working again.

Recursive sub folder search and return files in a list python

Recursive is new in Python 3.5, so it won't work on Python 2.7. Here is the example that uses r strings so you just need to provide the path as is on either Win, Lin, ...

import glob

mypath=r"C:\Users\dj\Desktop\nba"

files = glob.glob(mypath + r'\**\*.py', recursive=True)
# print(files) # as list
for f in files:
    print(f) # nice looking single line per file

Note: It will list all files, no matter how deep it should go.

How to convert string into float in JavaScript?

Replace the comma with a dot.

This will only return 554:

var value = parseFloat("554,20")

This will return 554.20:

var value = parseFloat("554.20")

So in the end, you can simply use:

var fValue = parseFloat(document.getElementById("textfield").value.replace(",","."))

Don't forget that parseInt() should only be used to parse integers (no floating points). In your case it will only return 554. Additionally, calling parseInt() on a float will not round the number: it will take its floor (closest lower integer).


Extended example to answer Pedro Ferreira's question from the comments:

If the textfield contains thousands separator dots like in 1.234.567,99 those could be eliminated beforehand with another replace:

var fValue = parseFloat(document.getElementById("textfield").value.replace(/\./g,"").replace(",","."))

How to express a One-To-Many relationship in Django

To be more clear - there's no OneToMany in Django, only ManyToOne - which is Foreignkey described above. You can describe OneToMany relation using Foreignkey but that is very inexpressively.

A good article about it: https://amir.rachum.com/blog/2013/06/15/a-case-for-a-onetomany-relationship-in-django/

Adding integers to an int array

org.apache.commons.lang.ArrayUtils can do this

num = (int []) ArrayUtils.add(num, 12);     // builds new array with 12 appended

How to move certain commits to be based on another branch in git?

You can use git cherry-pick to just pick the commit that you want to copy over.

Probably the best way is to create the branch out of master, then in that branch use git cherry-pick on the 2 commits from quickfix2 that you want.

How can I use threading in Python?

Since this question was asked in 2010, there has been real simplification in how to do simple multithreading with Python with map and pool.

The code below comes from an article/blog post that you should definitely check out (no affiliation) - Parallelism in one line: A Better Model for Day to Day Threading Tasks. I'll summarize below - it ends up being just a few lines of code:

from multiprocessing.dummy import Pool as ThreadPool
pool = ThreadPool(4)
results = pool.map(my_function, my_array)

Which is the multithreaded version of:

results = []
for item in my_array:
    results.append(my_function(item))

Description

Map is a cool little function, and the key to easily injecting parallelism into your Python code. For those unfamiliar, map is something lifted from functional languages like Lisp. It is a function which maps another function over a sequence.

Map handles the iteration over the sequence for us, applies the function, and stores all of the results in a handy list at the end.

Enter image description here


Implementation

Parallel versions of the map function are provided by two libraries:multiprocessing, and also its little known, but equally fantastic step child:multiprocessing.dummy.

multiprocessing.dummy is exactly the same as multiprocessing module, but uses threads instead (an important distinction - use multiple processes for CPU-intensive tasks; threads for (and during) I/O):

multiprocessing.dummy replicates the API of multiprocessing, but is no more than a wrapper around the threading module.

import urllib2
from multiprocessing.dummy import Pool as ThreadPool

urls = [
  'http://www.python.org',
  'http://www.python.org/about/',
  'http://www.onlamp.com/pub/a/python/2003/04/17/metaclasses.html',
  'http://www.python.org/doc/',
  'http://www.python.org/download/',
  'http://www.python.org/getit/',
  'http://www.python.org/community/',
  'https://wiki.python.org/moin/',
]

# Make the Pool of workers
pool = ThreadPool(4)

# Open the URLs in their own threads
# and return the results
results = pool.map(urllib2.urlopen, urls)

# Close the pool and wait for the work to finish
pool.close()
pool.join()

And the timing results:

Single thread:   14.4 seconds
       4 Pool:   3.1 seconds
       8 Pool:   1.4 seconds
      13 Pool:   1.3 seconds

Passing multiple arguments (works like this only in Python 3.3 and later):

To pass multiple arrays:

results = pool.starmap(function, zip(list_a, list_b))

Or to pass a constant and an array:

results = pool.starmap(function, zip(itertools.repeat(constant), list_a))

If you are using an earlier version of Python, you can pass multiple arguments via this workaround).

(Thanks to user136036 for the helpful comment.)

How to get the ASCII value of a character

To get the ASCII code of a character, you can use the ord() function.

Here is an example code:

value = input("Your value here: ")
list=[ord(ch) for ch in value]
print(list)

Output:

Your value here: qwerty
[113, 119, 101, 114, 116, 121]

What REST PUT/POST/DELETE calls should return by a convention?

Forgive the flippancy, but if you are doing REST over HTTP then RFC7231 describes exactly what behaviour is expected from GET, PUT, POST and DELETE.

Update (Jul 3 '14):
The HTTP spec intentionally does not define what is returned from POST or DELETE. The spec only defines what needs to be defined. The rest is left up to the implementer to choose.

What is boilerplate code?

On the etymology the term boilerplate: from http://www.takeourword.com/Issue009.html...

Interestingly, the term arose from the newspaper business. Columns and other pieces that were syndicated were sent out to subscribing newspapers in the form of a mat (i.e. a matrix). Once received, boiling lead was poured into this mat to create the plate used to print the piece, hence the name boilerplate. As the article printed on a boilerplate could not be altered, the term came to be used by attorneys to refer to the portions of a contract which did not change through repeated uses in different applications, and finally to language in general which did not change in any document that was used repeatedly for different occasions.

What constitutes boilerplate in programming? As may others have pointed out, it is just a chunk of code that is copied over and over again with little or no changes made to it in the process.

Maven:Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.7:resources

I faced the same problem and did the filtering false like below working for me. You can try the same...

<testResources>
    <testResource>
        <directory>src/test/java</directory>
        <filtering>false</filtering>
    </testResource>
    <testResource>
        <directory>src/test/resources</directory>
        <filtering>false</filtering>
    </testResource>
</testResources>

Insert into C# with SQLCommand

using (SqlConnection connection = new SqlConnection(connectionString)) 
{
    connection.Open(); 
    using (SqlCommand command = connection.CreateCommand()) 
    { 
        command.CommandText = "INSERT INTO klant(klant_id,naam,voornaam) VALUES(@param1,@param2,@param3)";  

        command.Parameters.AddWithValue("@param1", klantId));  
        command.Parameters.AddWithValue("@param2", klantNaam));  
        command.Parameters.AddWithValue("@param3", klantVoornaam));  

        command.ExecuteNonQuery(); 
    } 
}

Unresolved reference issue in PyCharm

The easiest way to fix it is by doing the following in your pyCharm software:

Click on: File > Settings > (Project: your project name) > Project Interpreter >

then click on the "+" icon on the right side to search for the package you want and install it.

Enjoy coding !!!

Adding headers to requests module

You can also do this to set a header for all future gets for the Session object, where x-test will be in all s.get() calls:

s = requests.Session()
s.auth = ('user', 'pass')
s.headers.update({'x-test': 'true'})

# both 'x-test' and 'x-test2' are sent
s.get('http://httpbin.org/headers', headers={'x-test2': 'true'})

from: http://docs.python-requests.org/en/latest/user/advanced/#session-objects

How to use (install) dblink in PostgreSQL?

Installing modules usually requires you to run an sql script that is included with the database installation.

Assuming linux-like OS

find / -name dblink.sql

Verify the location and run it

Bootstrap: Open Another Modal in Modal

For bootstrap 4, to expand on @helloroy's answer I used the following;-

var modal_lv = 0 ;
$('body').on('shown.bs.modal', function(e) {
    if ( modal_lv > 0 )
    {
        $('.modal-backdrop:last').css('zIndex',1050+modal_lv) ;
        $(e.target).css('zIndex',1051+modal_lv) ;
    }
    modal_lv++ ;
}).on('hidden.bs.modal', function() {
    if ( modal_lv > 0 )
        modal_lv-- ;
});

The advantage of the above is that it won't have any effect when there is only one modal, it only kicks in for multiples. Secondly, it delegates the handling to the body to ensure future modals which are not currently generated are still catered for.

Update

Moving to a js/css combined solution improves the look - the fade animation continues to work on the backdrop;-

var modal_lv = 0 ;
$('body').on('show.bs.modal', function(e) {
    if ( modal_lv > 0 )
        $(e.target).css('zIndex',1051+modal_lv) ;
    modal_lv++ ;
}).on('hidden.bs.modal', function() {
    if ( modal_lv > 0 )
        modal_lv-- ;
});

combined with the following css;-

.modal-backdrop ~ .modal-backdrop
{
    z-index : 1051 ;
}
.modal-backdrop ~ .modal-backdrop ~ .modal-backdrop
{
    z-index : 1052 ;
}
.modal-backdrop ~ .modal-backdrop ~ .modal-backdrop ~ .modal-backdrop
{
    z-index : 1053 ;
}

This will handle modals nested up to 4 deep which is more than I need.

How do I remove the horizontal scrollbar in a div?

To hide the horizontal scrollbar, we can just select the scrollbar of the required div and set it to display: none;

One thing to note is that this will only work for WebKit-based browsers (like Chrome) as there is no such option available for Mozilla.

In order to select the scrollbar, use ::-webkit-scrollbar

So the final code will be like this:

div::-webkit-scrollbar {
  display: none;
}

Converting list to *args when calling function

yes, using *arg passing args to a function will make python unpack the values in arg and pass it to the function.

so:

>>> def printer(*args):
 print args


>>> printer(2,3,4)
(2, 3, 4)
>>> printer(*range(2, 5))
(2, 3, 4)
>>> printer(range(2, 5))
([2, 3, 4],)
>>> 

Is it possible to delete an object's property in PHP?

This also works specially if you are looping over an object.

unset($object[$key])

Update

Newer versions of PHP throw fatal error Fatal error: Cannot use object of type Object as array as mentioned by @CXJ . In that case you can use brackets instead

unset($object->{$key})

TypeError: $.ajax(...) is not a function?

If you are using bootstrap html template remember to remove the link to jquery slim at the bottom of the template. I post this detail here as I cannot comment answers yet..

How to iterate over a std::map full of strings in C++

  1. Don't write a toString() method. This is not Java. Implement the stream operator for your class.

  2. Prefer using the standard algorithms over writing your own loop. In this situation, std::for_each() provides a nice interface to what you want to do.

  3. If you must use a loop, but don't intend to change the data, prefer const_iterator over iterator. That way, if you accidently try and change the values, the compiler will warn you.

Then:

std::ostream& operator<<(std::ostream& str,something const& data)
{
    data.print(str)
    return str;
}

void something::print(std::ostream& str) const
{
    std::for_each(table.begin(),table.end(),PrintData(str));
}

Then when you want to print it, just stream the object:

int main()
{
    something    bob;
    std::cout << bob;
}

If you actually need a string representation of the object, you can then use lexical_cast.

int main()
{
    something    bob;

    std::string  rope = boost::lexical_cast<std::string>(bob);
}

The details that need to be filled in.

class somthing
{
    typedef std::map<std::string,std::string>    DataMap;
    struct PrintData
    {
         PrintData(std::ostream& str): m_str(str) {}
         void operator()(DataMap::value_type const& data) const
         {
             m_str << data.first << "=" << data.second << "\n";
         }
         private:  std::ostream& m_str;
    };
    DataMap    table;
    public:
        void something::print(std::ostream& str);
};

Android Studio emulator does not come with Play Store for API 23

As of now, Installing the apks to the /system directory seems to be working using adb push command.

Some hidden service was automatically remounting the /system directory in read-only mode.

Any way I was able to install the Play store in a normal virtual-machine ( Ie, non-Google-Api virtual machine ) by simply mounting the system.img file from my OS and by copying over the files.

# To be executed as root user in your Unix based OS
mkdir sys_temp
mount $SDK_HOME/system-images/android-23/default/x86/system.img sys_temp -o loop
cp Phonesky.apk GmsCore.apk GoogleLoginService.apk GoogleServicesFramework.apk ./sys_temp/priv-app/
umount sys_temp
rmdir sys_temp

The APK files can be pulled from any real Android device running Google Apps by using adb pull command

[ To get the exact path of the apks, we can use command pm list packages -f inside the adb shell ]

How to use global variable in node.js?

Global variables can be used in Node when used wisely.

Declaration of global variables in Node:

a = 10;
GLOBAL.a = 10;
global.a = 10;

All of the above commands the same actions with different syntaxes.

Use global variables when they are not about to be changed

Here an example of something that can happen when using global variables:

// app.js
a = 10; // no var or let or const means global

// users.js
app.get("/users", (req, res, next) => {
   res.send(a); // 10;
});

// permissions.js
app.get("/permissions", (req, res, next) => {
   a = 11; // notice that there is no previous declaration of a in the permissions.js, means we looking for the global instance of a.
   res.send(a); // 11;
});

Explained:

Run users route first and receive 10;

Then run permissions route and receive 11;

Then run again the users route and receive 11 as well instead of 10;

Global variables can be overtaken!

Now think about using express and assignin res object as global.. And you end up with async error become corrupt and server is shuts down.

When to use global vars?

As I said - when var is not about to be changed. Anyways it's more recommended that you will be using the process.env object from the config file.

Pyspark: Exception: Java gateway process exited before sending the driver its port number

I go this error fixed by using the below code. I had setup the SPARK_HOME though. You may follow this simple steps from eproblems website

spark_home = os.environ.get('SPARK_HOME', None)

Python: How to remove empty lists from a list?

>>> list1 = [[], [], [], [], [], 'text', 'text2', [], 'moreText']
>>> list2 = [e for e in list1 if e]
>>> list2
['text', 'text2', 'moreText']

How do I use floating-point division in bash?

** Injection-safe floating point math in bash/shell **

Note: The focus of this answer is provide ideas for injection-safe solution to performing math in bash (or other shells). Of course, same can be used, with minor adjustment to perform advanced string processing, etc.

Most of the solution that were by presented, construct small scriptlet on the fly, using external data (variables, files, command line, environment variables). The external input can be used to inject malicious code into the engine, many of them

Below is a comparison on using the various language to perform basic math calculation, where the result in floating point. It calculates A + B * 0.1 (as floating point).

All solution attempt avoid creating dynamic scriptlets, which are extremely hard to maintain, Instead they use static program, and pass parameters into designated variable. They will safely handle parameters with special characters - reducing the possibility of code injection. The exception is 'BC' which does not provide input/output facility

The exception is 'bc', which does not provide any input/output, all the data comes via programs in stdin, and all output goes to stdout. All calculation are executing in a sandbox, which does not allow side effect (opening files, etc.). In theory, injection safe by design!

A=5.2
B=4.3

# Awk: Map variable into awk
# Exit 0 (or just exit) for success, non-zero for error.
#
awk -v A="$A" -v B="$B" 'BEGIN { print A + B * 0.1 ; exit 0}'

# Perl
perl -e '($A,$B) = @ARGV ; print $A + $B * 0.1' "$A" "$B"

# Python 2
python -c 'import sys ; a = float(sys.argv[1]) ; b = float(sys.argv[2]) ; print a+b*0.1' "$A" "$B"

# Python 3
python3 -c 'import sys ; a = float(sys.argv[1]) ; b = float(sys.argv[2]) ; print(a+b*0.1)' "$A" "$B"

# BC
bc <<< "scale=1 ; $A + $B * 0.1"

How to append rows in a pandas dataframe in a for loop?

Suppose your data looks like this:

import pandas as pd
import numpy as np

np.random.seed(2015)
df = pd.DataFrame([])
for i in range(5):
    data = dict(zip(np.random.choice(10, replace=False, size=5),
                    np.random.randint(10, size=5)))
    data = pd.DataFrame(data.items())
    data = data.transpose()
    data.columns = data.iloc[0]
    data = data.drop(data.index[[0]])
    df = df.append(data)
print('{}\n'.format(df))
# 0   0   1   2   3   4   5   6   7   8   9
# 1   6 NaN NaN   8   5 NaN NaN   7   0 NaN
# 1 NaN   9   6 NaN   2 NaN   1 NaN NaN   2
# 1 NaN   2   2   1   2 NaN   1 NaN NaN NaN
# 1   6 NaN   6 NaN   4   4   0 NaN NaN NaN
# 1 NaN   9 NaN   9 NaN   7   1   9 NaN NaN

Then it could be replaced with

np.random.seed(2015)
data = []
for i in range(5):
    data.append(dict(zip(np.random.choice(10, replace=False, size=5),
                         np.random.randint(10, size=5))))
df = pd.DataFrame(data)
print(df)

In other words, do not form a new DataFrame for each row. Instead, collect all the data in a list of dicts, and then call df = pd.DataFrame(data) once at the end, outside the loop.

Each call to df.append requires allocating space for a new DataFrame with one extra row, copying all the data from the original DataFrame into the new DataFrame, and then copying data into the new row. All that allocation and copying makes calling df.append in a loop very inefficient. The time cost of copying grows quadratically with the number of rows. Not only is the call-DataFrame-once code easier to write, it's performance will be much better -- the time cost of copying grows linearly with the number of rows.

Can a PDF file's print dialog be opened with Javascript?

If you are using the prawn gem for Ruby on Rails to generate your PDF, you can use the following additional gem to active the print dialog:

prawn-print

How does String.Index work in Swift

enter image description here

All of the following examples use

var str = "Hello, playground"

startIndex and endIndex

  • startIndex is the index of the first character
  • endIndex is the index after the last character.

Example

// character
str[str.startIndex] // H
str[str.endIndex]   // error: after last character

// range
let range = str.startIndex..<str.endIndex
str[range]  // "Hello, playground"

With Swift 4's one-sided ranges, the range can be simplified to one of the following forms.

let range = str.startIndex...
let range = ..<str.endIndex

I will use the full form in the follow examples for the sake of clarity, but for the sake of readability, you will probably want to use the one-sided ranges in your code.

after

As in: index(after: String.Index)

  • after refers to the index of the character directly after the given index.

Examples

// character
let index = str.index(after: str.startIndex)
str[index]  // "e"

// range
let range = str.index(after: str.startIndex)..<str.endIndex
str[range]  // "ello, playground"

before

As in: index(before: String.Index)

  • before refers to the index of the character directly before the given index.

Examples

// character
let index = str.index(before: str.endIndex)
str[index]  // d

// range
let range = str.startIndex..<str.index(before: str.endIndex)
str[range]  // Hello, playgroun

offsetBy

As in: index(String.Index, offsetBy: String.IndexDistance)

  • The offsetBy value can be positive or negative and starts from the given index. Although it is of the type String.IndexDistance, you can give it an Int.

Examples

// character
let index = str.index(str.startIndex, offsetBy: 7)
str[index]  // p

// range
let start = str.index(str.startIndex, offsetBy: 7)
let end = str.index(str.endIndex, offsetBy: -6)
let range = start..<end
str[range]  // play

limitedBy

As in: index(String.Index, offsetBy: String.IndexDistance, limitedBy: String.Index)

  • The limitedBy is useful for making sure that the offset does not cause the index to go out of bounds. It is a bounding index. Since it is possible for the offset to exceed the limit, this method returns an Optional. It returns nil if the index is out of bounds.

Example

// character
if let index = str.index(str.startIndex, offsetBy: 7, limitedBy: str.endIndex) {
    str[index]  // p
}

If the offset had been 77 instead of 7, then the if statement would have been skipped.

Why is String.Index needed?

It would be much easier to use an Int index for Strings. The reason that you have to create a new String.Index for every String is that Characters in Swift are not all the same length under the hood. A single Swift Character might be composed of one, two, or even more Unicode code points. Thus each unique String must calculate the indexes of its Characters.

It is possibly to hide this complexity behind an Int index extension, but I am reluctant to do so. It is good to be reminded of what is actually happening.

All ASP.NET Web API controllers return 404

If you manage the IIS and you are the one who have to create new site then check the "Application Pool" and be sure the CLR version must be selected. In my situation, it had been selected "No Managed Code". After changed to v4.0 it started to work.

How can I create a copy of an Oracle table without copying the data?

create table xyz_new as select * from xyz where rownum = -1;

To avoid iterate again and again and insert nothing based on the condition where 1=2

What is the best way to exit a function (which has no return value) in python before the function ends (e.g. a check fails)?

I would suggest:

def foo(element):
    do something
    if not check: return
    do more (because check was succesful)
    do much much more...

CSS3's border-radius property and border-collapse:collapse don't mix. How can I use border-radius to create a collapsed table with rounded corners?

I just wrote a crazy set of CSS for this that seems to work perfectly:

table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
}
table td,
table th {
  border-right: 1px solid #CCC;
  border-top: 1px solid #CCC;
  padding: 3px 5px;
  vertical-align: top;
}
table td:first-child,
table th:first-child {
  border-left: 1px solid #CCC;
}
table tr:last-child td,
table tr:last-child th {
  border-bottom: 1px solid #CCC;
}
table thead + tbody tr:first-child td {
  border-top: 0;
}
table thead td,
table th {
  background: #EDEDED;
}

/* complicated rounded table corners! */
table thead:first-child tr:last-child td:first-child {
  border-bottom-left-radius: 0;
}
table thead:first-child tr:last-child td:last-child {
  border-bottom-right-radius: 0;
}
table thead + tbody tr:first-child td:first-child {
  border-top-left-radius: 0;
}
table thead + tbody tr:first-child td:last-child {
  border-top-right-radius: 0;
}
table tr:first-child td:first-child,
table thead tr:first-child td:first-child {
  border-top-left-radius: 5px;
}
table tr:first-child td:last-child,
table thead tr:first-child td:last-child {
  border-top-right-radius: 5px;
}
table tr:last-child td:first-child,
table thead:last-child tr:last-child td:first-child {
  border-bottom-left-radius: 5px;
}
table tr:last-child td:last-child,
table thead:last-child tr:last-child td:last-child {
  border-bottom-right-radius: 5px;
}

/* end complicated rounded table corners !*/

PHP Composer behind http proxy

If you're on Linux or Unix (including OS X), you should put this somewhere that will affect your environment:

export HTTP_PROXY_REQUEST_FULLURI=0 # or false
export HTTPS_PROXY_REQUEST_FULLURI=0 #

You can put it in /etc/profile to globally affect all users on the machine, or your own ~/.bashrc or ~/.zshrc, depending on which shell you use.

If you're on Windows, open the Environment Variables control panel, and add either a system or user environment variables with both HTTP_PROXY_REQUEST_FULLURI and HTTPS_PROXY_REQUEST_FULLURI set to 0 or false.

For other people reading this (not you, since you said you have these set up), make sure HTTP_PROXY and HTTPS_PROXY are set to the correct proxy, using the same methods. If you're on Unix/Linux/OS X, setting both upper and lowercase versions of the variable name is the most complete approach, as some things use only the lowercase version, and IIRC some use the upper case. (I'm often using a sort of hybrid environment, Cygwin on Windows, and I know for me it was important to have both, but pure Unix/Linux environments might be able to get away with just lowercase.)

If you still can't get things working after you've done all this, and you're sure you have the correct proxy address set, then look into whether your company is using a Microsoft proxy server. If so, you probably need to install Cntlm as a child proxy to connect between Composer (etc.) and the Microsoft proxy server. Google CNTLM for more information and directions on how to set it up.

How to parse a query string into a NameValueCollection in .NET

I just realized that Web API Client has a ParseQueryString extension method that works on a Uri and returns a HttpValueCollection:

var parameters = uri.ParseQueryString();
string foo = parameters["foo"];

How to implement swipe gestures for mobile devices?

The simplest solution I've found that doesn't require a plugin:

document.addEventListener('touchstart', handleTouchStart, false);        
document.addEventListener('touchmove', handleTouchMove, false);
var xDown = null;                                                        
var yDown = null;  

function handleTouchStart(evt) {                                         
    xDown = evt.touches[0].clientX;                                      
    yDown = evt.touches[0].clientY;                                      
}; 

function handleTouchMove(evt) {
    if ( ! xDown || ! yDown ) {
        return;
    }
    var xUp = evt.touches[0].clientX;                                    
    var yUp = evt.touches[0].clientY;
    var xDiff = xDown - xUp;
    var yDiff = yDown - yUp;

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

"Uncaught TypeError: a.indexOf is not a function" error when opening new foundation project

This error is often caused by incompatible jQuery versions. I encountered the same error with a foundation 6 repository. My repository was using jQuery 3, but foundation requires an earlier version. I then changed it and it worked.

If you look at the version of jQuery required by the foundation 5 dependencies it states "jquery": "~2.1.0".

Can you confirm that you are loading the correct version of jQuery?

I hope this helps.

Link to a section of a webpage

Hashtags at the end of the URL bring a visitor to the element with the ID: e.g.

http://stackoverflow.com/questions/8424785/link-to-a-section-of-a-webpage#answers 

Would bring you to where the DIV with the ID 'answers' begins. Also, you can use the name attribute in anchor tags, to create the same effect.

Resource

how to get selected row value in the KendoUI

There is better way. I'm using it in pages where I'm using kendo angularJS directives and grids has'nt IDs...

change: function (e) {
   var selectedDataItem = e != null ? e.sender.dataItem(e.sender.select()) : null;
}

php - How do I fix this illegal offset type error

There are probably less than 20 entries in your xml.

change the code to this

for ($i=0;$i< sizeof($xml->entry); $i++)
...

Swipe ListView item From right to left show delete button

i've searched google a lot and find the best suited project is the swipmenulistview https://github.com/baoyongzhang/SwipeMenuListView on github.

writing to serial port from linux command line

SCREEN:

NOTE: screen is actually not able to send hex, as far as I know. To do that, use echo or printf

I was using the suggestions in this post to write to a serial port, then using the info from another post to read from the port, with mixed results. I found that using screen is an "easier" solution, since it opens a terminal session directly with that port. (I put easier in quotes, because screen has a really weird interface, IMO, and takes some further reading to figure it out.)

You can issue this command to open a screen session, then anything you type will be sent to the port, plus the return values will be printed below it:

screen /dev/ttyS0 19200,cs8

(Change the above to fit your needs for speed, parity, stop bits, etc.) I realize screen isn't the "linux command line" as the post specifically asks for, but I think it's in the same spirit. Plus, you don't have to type echo and quotes every time.

ECHO:

Follow praetorian droid's answer. HOWEVER, this didn't work for me until I also used the cat command (cat < /dev/ttyS0) while I was sending the echo command.

PRINTF:

I found that one can also use printf's '%x' command:

c="\x"$(printf '%x' 0x12)
printf $c >> $SERIAL_COMM_PORT

Again, for printf, start cat < /dev/ttyS0 before sending the command.

copying all contents of folder to another folder using batch file?

xcopy.exe is the solution here. It's built into Windows.

xcopy /s c:\Folder1 d:\Folder2

You can find more options at http://www.computerhope.com/xcopyhlp.htm

Difference between webdriver.Dispose(), .Close() and .Quit()

My understanding is driver.close(); will close the current browser, and driver.quit(); will terminate all the browser that.

Type datetime for input parameter in procedure

In this part of your SP:

IF @DateFirst <> '' and @DateLast <> ''
   set @FinalSQL  = @FinalSQL
       + '  or convert (Date,DateLog) >=     ''' + @DateFirst
       + ' and convert (Date,DateLog) <=''' + @DateLast  

you are trying to concatenate strings and datetimes.

As the datetime type has higher priority than varchar/nvarchar, the + operator, when it happens between a string and a datetime, is interpreted as addition, not as concatenation, and the engine then tries to convert your string parts (' or convert (Date,DateLog) >= ''' and others) to datetime or numeric values. And fails.

That doesn't happen if you omit the last two parameters when invoking the procedure, because the condition evaluates to false and the offending statement isn't executed.

To amend the situation, you need to add explicit casting of your datetime variables to strings:

set @FinalSQL  = @FinalSQL
    + '  or convert (Date,DateLog) >=     ''' + convert(date, @DateFirst)
    + ' and convert (Date,DateLog) <=''' + convert(date, @DateLast)

You'll also need to add closing single quotes:

set @FinalSQL  = @FinalSQL
    + '  or convert (Date,DateLog) >=     ''' + convert(date, @DateFirst) + ''''
    + ' and convert (Date,DateLog) <=''' + convert(date, @DateLast) + ''''

How to empty/destroy a session in rails?

session in rails is a hash object. Hence any function available for clearing hash will work with sessions.

session.clear

or if specific keys have to be destroyed:

session.delete(key)

Tested in rails 3.2

added

People have mentioned by session={} is a bad idea. Regarding session.clear, Lobati comments- It looks like you're probably better off using reset_session [than session.clear], as it does some other cleaning up beyond what session.clear does. Internally, reset_session calls session.destroy, which itself calls clear as well some other stuff.

How many socket connections can a web server handle?

in case of the IPv4 protocol, the server with one IP address that listens on one port only can handle 2^32 IP addresses x 2^16 ports so 2^48 unique sockets. If you speak about a server as a physical machine, and you are able to utilize all 2^16 ports, then there could be maximum of 2^48 x 2^16 = 2^64 unique TCP/IP sockets for one IP address. Please note that some ports are reserved for the OS, so this number will be lower. To sum up:

1 IP and 1 port --> 2^48 sockets

1 IP and all ports --> 2^64 sockets

all unique IPv4 sockets in the universe --> 2^96 sockets

Error: Failed to lookup view in Express

I had the same issue and could fix it with the solution from dougwilson: from Apr 5, 2017, Github.

  1. I changed the filename from index.js to index.pug
  2. Then used in the '/' route: res.render('index.pug') - instead of res.render('index')
  3. Set environment variable: DEBUG=express:view Now it works like a charm.

How can you change Network settings (IP Address, DNS, WINS, Host Name) with code in C#

Refactored the code from balexandre a little so objects gets disposed and the new language features of C# 3.5+ are used (Linq, var, etc). Also renamed the variables to more meaningful names. I also merged some of the functions to be able to do more configuration with less WMI interaction. I removed the WINS code as I don't need to configure WINS anymore. Feel free to add the WINS code if you need it.

For the case anybody likes to use the refactored/modernized code I put it back into the community here.

/// <summary>
/// Helper class to set networking configuration like IP address, DNS servers, etc.
/// </summary>
public class NetworkConfigurator
{
    /// <summary>
    /// Set's a new IP Address and it's Submask of the local machine
    /// </summary>
    /// <param name="ipAddress">The IP Address</param>
    /// <param name="subnetMask">The Submask IP Address</param>
    /// <param name="gateway">The gateway.</param>
    /// <remarks>Requires a reference to the System.Management namespace</remarks>
    public void SetIP(string ipAddress, string subnetMask, string gateway)
    {
        using (var networkConfigMng = new ManagementClass("Win32_NetworkAdapterConfiguration"))
        {
            using (var networkConfigs = networkConfigMng.GetInstances())
            {
                foreach (var managementObject in networkConfigs.Cast<ManagementObject>().Where(managementObject => (bool)managementObject["IPEnabled"]))
                {
                    using (var newIP = managementObject.GetMethodParameters("EnableStatic"))
                    {
                        // Set new IP address and subnet if needed
                        if ((!String.IsNullOrEmpty(ipAddress)) || (!String.IsNullOrEmpty(subnetMask)))
                        {
                            if (!String.IsNullOrEmpty(ipAddress))
                            {
                                newIP["IPAddress"] = new[] { ipAddress };
                            }

                            if (!String.IsNullOrEmpty(subnetMask))
                            {
                                newIP["SubnetMask"] = new[] { subnetMask };
                            }

                            managementObject.InvokeMethod("EnableStatic", newIP, null);
                        }

                        // Set mew gateway if needed
                        if (!String.IsNullOrEmpty(gateway))
                        {
                            using (var newGateway = managementObject.GetMethodParameters("SetGateways"))
                            {
                                newGateway["DefaultIPGateway"] = new[] { gateway };
                                newGateway["GatewayCostMetric"] = new[] { 1 };
                                managementObject.InvokeMethod("SetGateways", newGateway, null);
                            }
                        }
                    }
                }
            }
        }
    }

    /// <summary>
    /// Set's the DNS Server of the local machine
    /// </summary>
    /// <param name="nic">NIC address</param>
    /// <param name="dnsServers">Comma seperated list of DNS server addresses</param>
    /// <remarks>Requires a reference to the System.Management namespace</remarks>
    public void SetNameservers(string nic, string dnsServers)
    {
        using (var networkConfigMng = new ManagementClass("Win32_NetworkAdapterConfiguration"))
        {
            using (var networkConfigs = networkConfigMng.GetInstances())
            {
                foreach (var managementObject in networkConfigs.Cast<ManagementObject>().Where(objMO => (bool)objMO["IPEnabled"] && objMO["Caption"].Equals(nic)))
                {
                    using (var newDNS = managementObject.GetMethodParameters("SetDNSServerSearchOrder"))
                    {
                        newDNS["DNSServerSearchOrder"] = dnsServers.Split(',');
                        managementObject.InvokeMethod("SetDNSServerSearchOrder", newDNS, null);
                    }
                }
            }
        }
    }
}

How to checkout a specific Subversion revision from the command line?

Either

svn checkout url://repository/path@1234

or

svn checkout -r 1234 url://repository/path

array_push() with key value pair

If you need to add multiple key=>value, then try this.

$data = array_merge($data, array("cat"=>"wagon","foo"=>"baar"));

How to hide status bar in Android

If you refer to the Google Documents you can use this method for android 4.1 and above, call this method before setContentView()

public void hideStatusBar() {
    View view = getWindow().getDecorView();
    int uiOption = View.SYSTEM_UI_FLAG_FULLSCREEN;
    view.setSystemUiVisibility(uiOption);
    ActionBar actionBar = getActionBar();
    if (actionBar != null) {
        actionBar.hide();
    }
}

What are the differences between LDAP and Active Directory?

LDAP is a standard, AD is Microsoft's (proprietary) implementation (and more). Wikipedia has a good article that delves into the specifics. I found this document with a very detailed evaluation of AD from an LDAP perspective.

How to execute two mysql queries as one in PHP/MYSQL?

You'll have to use the MySQLi extension if you don't want to execute a query twice:

if (mysqli_multi_query($link, $query))
{
    $result1 = mysqli_store_result($link);
    $result2 = null;

    if (mysqli_more_results($link))
    {
        mysqli_next_result($link);
        $result2 = mysqli_store_result($link);
    }

    // do something with both result sets.

    if ($result1)
        mysqli_free_result($result1);

    if ($result2)
        mysqli_free_result($result2);
}

string decode utf-8

the core functions are getBytes(String charset) and new String(byte[] data). you can use these functions to do UTF-8 decoding.

UTF-8 decoding actually is a string to string conversion, the intermediate buffer is a byte array. since the target is an UTF-8 string, so the only parameter for new String() is the byte array, which calling is equal to new String(bytes, "UTF-8")

Then the key is the parameter for input encoded string to get internal byte array, which you should know beforehand. If you don't, guess the most possible one, "ISO-8859-1" is a good guess for English user.

The decoding sentence should be

String decoded = new String(encoded.getBytes("ISO-8859-1"));

How do I show multiple recaptchas on a single page?

A good option is to generate a recaptcha input for each form on the fly (I've done it with two but you could probably do three or more forms). I'm using jQuery, jQuery validation, and jQuery form plugin to post the form via AJAX, along with the Recaptcha AJAX API -

https://developers.google.com/recaptcha/docs/display#recaptcha_methods

When the user submits one of the forms:

  1. intercept the submission - I used jQuery Form Plugin's beforeSubmit property
  2. destroy any existing recaptcha inputs on the page - I used jQuery's $.empty() method and Recaptcha.destroy()
  3. call Recaptcha.create() to create a recaptcha field for the specific form
  4. return false.

Then, they can fill out the recaptcha and re-submit the form. If they decide to submit a different form instead, well, your code checks for existing recaptchas so you'll only have one recaptcha on the page at a time.

How to download an entire directory and subdirectories using wget?

you can also use this command :

wget --mirror -pc --convert-links -P ./your-local-dir/ http://www.your-website.com

so that you get the exact mirror of the website you want to download

How to compare two maps by their values

All of these are returning equals. They arent actually doing a comparison, which is useful for sort. This will behave more like a comparator:

private static final Comparator stringFallbackComparator = new Comparator() {
    public int compare(Object o1, Object o2) {
        if (!(o1 instanceof Comparable))
            o1 = o1.toString();
        if (!(o2 instanceof Comparable))
            o2 = o2.toString();
        return ((Comparable)o1).compareTo(o2);
    }
};

public int compare(Map m1, Map m2) {
    TreeSet s1 = new TreeSet(stringFallbackComparator); s1.addAll(m1.keySet());
    TreeSet s2 = new TreeSet(stringFallbackComparator); s2.addAll(m2.keySet());
    Iterator i1 = s1.iterator();
    Iterator i2 = s2.iterator();
    int i;
    while (i1.hasNext() && i2.hasNext())
    {
        Object k1 = i1.next();
        Object k2 = i2.next();
        if (0!=(i=stringFallbackComparator.compare(k1, k2)))
            return i;
        if (0!=(i=stringFallbackComparator.compare(m1.get(k1), m2.get(k2))))
            return i;
    }
    if (i1.hasNext())
        return 1;
    if (i2.hasNext())
        return -1;
    return 0;
}

How to set selected item of Spinner by value, not by position?

I am using a custom adapter, for that this code is enough:

yourSpinner.setSelection(arrayAdapter.getPosition("Your Desired Text"));

So, your code snippet will be like this:

void setSpinner(String value)
    {
         yourSpinner.setSelection(arrayAdapter.getPosition(value));
    }

Convert Numeric value to Varchar

First convert the numeric value then add the 'S':

 select convert(varchar(10),StandardCost) +'S'
 from DimProduct where ProductKey = 212

Hex colors: Numeric representation for "transparent"?

You can use this conversion table: http://roselab.jhu.edu/~raj/MISC/hexdectxt.html

eg, if you want a transparency of 60%, you use 3C (hex equivalent).

This is usefull for IE background gradient transparency:

filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#3C545454, endColorstr=#3C545454);
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#3C545454, endColorstr=#3C545454)";

where startColorstr and endColorstr: 2 first characters are a hex value for transparency, and the six remaining are the hex color.

What's the better (cleaner) way to ignore output in PowerShell?

I realize this is an old thread, but for those taking @JasonMArcher's accepted answer above as fact, I'm surprised it has not been corrected many of us have known for years it is actually the PIPELINE adding the delay and NOTHING to do with whether it is Out-Null or not. In fact, if you run the tests below you will quickly see that the same "faster" casting to [void] and $void= that for years we all used thinking it was faster, are actually JUST AS SLOW and in fact VERY SLOW when you add ANY pipelining whatsoever. In other words, as soon as you pipe to anything, the whole rule of not using out-null goes into the trash.

Proof, the last 3 tests in the list below. The horrible Out-null was 32339.3792 milliseconds, but wait - how much faster was casting to [void]? 34121.9251 ms?!? WTF? These are REAL #s on my system, casting to VOID was actually SLOWER. How about =$null? 34217.685ms.....still friggin SLOWER! So, as the last three simple tests show, the Out-Null is actually FASTER in many cases when the pipeline is already in use.

So, why is this? Simple. It is and always was 100% a hallucination that piping to Out-Null was slower. It is however that PIPING TO ANYTHING is slower, and didn't we kind of already know that through basic logic? We just may not have know HOW MUCH slower, but these tests sure tell a story about the cost of using the pipeline if you can avoid it. And, we were not really 100% wrong because there is a very SMALL number of true scenarios where out-null is evil. When? When adding Out-Null is adding the ONLY pipeline activity. In other words....the reason a simple command like $(1..1000) | Out-Null as shown above showed true.

If you simply add an additional pipe to Out-String to every test above, the #s change radically (or just paste the ones below) and as you can see for yourself, the Out-Null actually becomes FASTER in many cases:

$GetProcess = Get-Process

# Batch 1 - Test 1 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$GetProcess | Out-Null 
} 
}).TotalMilliseconds

# Batch 1 - Test 2 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
[void]($GetProcess) 
} 
}).TotalMilliseconds

# Batch 1 - Test 3 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$null = $GetProcess 
} 
}).TotalMilliseconds

# Batch 2 - Test 1 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$GetProcess | Select-Object -Property ProcessName | Out-Null 
} 
}).TotalMilliseconds

# Batch 2 - Test 2 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
[void]($GetProcess | Select-Object -Property ProcessName ) 
} 
}).TotalMilliseconds

# Batch 2 - Test 3 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$null = $GetProcess | Select-Object -Property ProcessName 
} 
}).TotalMilliseconds

# Batch 3 - Test 1 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$GetProcess | Select-Object -Property Handles, NPM, PM, WS, VM, CPU, Id, SI, Name | Out-Null 
} 
}).TotalMilliseconds

# Batch 3 - Test 2 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
[void]($GetProcess | Select-Object -Property Handles, NPM, PM, WS, VM, CPU, Id, SI, Name ) 
} 
}).TotalMilliseconds

# Batch 3 - Test 3 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$null = $GetProcess | Select-Object -Property Handles, NPM, PM, WS, VM, CPU, Id, SI, Name 
} 
}).TotalMilliseconds

# Batch 4 - Test 1 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$GetProcess | Out-String | Out-Null 
} 
}).TotalMilliseconds

# Batch 4 - Test 2 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
[void]($GetProcess | Out-String ) 
} 
}).TotalMilliseconds

# Batch 4 - Test 3 
(Measure-Command { 
for ($i = 1; $i -lt 99; $i++) 
{ 
$null = $GetProcess | Out-String 
} 
}).TotalMilliseconds

How to get rid of "Unnamed: 0" column in a pandas DataFrame?

To get ride of all Unnamed columns, you can also use regex such as df.drop(df.filter(regex="Unname"),axis=1, inplace=True)

Merge, update, and pull Git branches without using checkouts

For many GitFlow users the most useful commands are:

git fetch origin master:master --update-head-ok
git fetch origin dev:dev --update-head-ok

The --update-head-ok flag allows using the same command while on dev or master branches.

A handy alias in .gitconfig:

[alias]
    f=!git fetch origin master:master --update-head-ok && git fetch origin dev:dev --update-head-ok

Comparing two hashmaps for equal values and same key sets?

Compare every key in mapB against the counterpart in mapA. Then check if there is any key in mapA not existing in mapB

public boolean mapsAreEqual(Map<String, String> mapA, Map<String, String> mapB) {

    try{
        for (String k : mapB.keySet())
        {
            if (!mapA.get(k).equals(mapB.get(k))) {
                return false;
            }
        } 
        for (String y : mapA.keySet())
        {
            if (!mapB.containsKey(y)) {
                return false;
            }
        } 
    } catch (NullPointerException np) {
        return false;
    }
    return true;
}

AngularJS - $http.post send data as json

Consider explicitly setting the header in the $http.post (I put application/json, as I am not sure which of the two versions in your example is the working one, but you can use application/x-www-form-urlencoded if it's the other one):

$http.post("/customer/data/autocomplete", {term: searchString}, {headers: {'Content-Type': 'application/json'} })
        .then(function (response) {
            return response;
        });

Android - save/restore fragment state

Android fragment has some advantages and some disadvantages. The most disadvantage of the fragment is that when you want to use a fragment you create it ones. When you use it, onCreateView of the fragment is called for each time. If you want to keep state of the components in the fragment you must save fragment state and yout must load its state in the next shown. This make fragment view a bit slow and weird.

I have found a solution and I have used this solution: "Everything is great. Every body can try".

When first time onCreateView is being run, create view as a global variable. When second time you call this fragment onCreateView is called again you can return this global view. The fragment component state will be kept.

View view;

@Override
public View onCreateView(LayoutInflater inflater,
        @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    setActionBar(null);
    if (view != null) {
        if ((ViewGroup)view.getParent() != null)
            ((ViewGroup)view.getParent()).removeView(view);
        return view; 
    }
    view = inflater.inflate(R.layout.mylayout, container, false);
}

LINQ equivalent of foreach for IEnumerable<T>

Inspired by Jon Skeet, I have extended his solution with the following:

Extension Method:

public static void Execute<TSource, TKey>(this IEnumerable<TSource> source, Action<TKey> applyBehavior, Func<TSource, TKey> keySelector)
{
    foreach (var item in source)
    {
        var target = keySelector(item);
        applyBehavior(target);
    }
}

Client:

var jobs = new List<Job>() 
    { 
        new Job { Id = "XAML Developer" }, 
        new Job { Id = "Assassin" }, 
        new Job { Id = "Narco Trafficker" }
    };

jobs.Execute(ApplyFilter, j => j.Id);

. . .

    public void ApplyFilter(string filterId)
    {
        Debug.WriteLine(filterId);
    }

Scala: join an iterable of strings

How about mkString ?

theStrings.mkString(",")

A variant exists in which you can specify a prefix and suffix too.

See here for an implementation using foldLeft, which is much more verbose, but perhaps worth looking at for education's sake.

How to add Action bar options menu in Android Fragments

You need to call setHasOptionsMenu(true) in onCreate().

For backwards compatibility it's better to place this call as late as possible at the end of onCreate() or even later in onActivityCreated() or something like that.

See: https://developer.android.com/reference/android/app/Fragment.html#setHasOptionsMenu(boolean)

How do I set the figure title and axes labels font size in Matplotlib?

If you're more used to using ax objects to do your plotting, you might find the ax.xaxis.label.set_size() easier to remember, or at least easier to find using tab in an ipython terminal. It seems to need a redraw operation after to see the effect. For example:

import matplotlib.pyplot as plt

# set up a plot with dummy data
fig, ax = plt.subplots()
x = [0, 1, 2]
y = [0, 3, 9]
ax.plot(x,y)

# title and labels, setting initial sizes
fig.suptitle('test title', fontsize=12)
ax.set_xlabel('xlabel', fontsize=10)
ax.set_ylabel('ylabel', fontsize='medium')   # relative to plt.rcParams['font.size']

# setting label sizes after creation
ax.xaxis.label.set_size(20)
plt.draw()

I don't know of a similar way to set the suptitle size after it's created.

Ruby: How to get the first character of a string

Try this:

def word(string, num)
    string = 'Smith'
    string[0..(num-1)]
end

How to use variables in SQL statement in Python?

Many ways. DON'T use the most obvious one (%s with %) in real code, it's open to attacks.

Here copy-paste'd from pydoc of sqlite3:

# Never do this -- insecure!
symbol = 'RHAT'
c.execute("SELECT * FROM stocks WHERE symbol = '%s'" % symbol)

# Do this instead
t = ('RHAT',)
c.execute('SELECT * FROM stocks WHERE symbol=?', t)
print c.fetchone()

# Larger example that inserts many records at a time
purchases = [('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
             ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00),
             ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
            ]
c.executemany('INSERT INTO stocks VALUES (?,?,?,?,?)', purchases)

More examples if you need:

# Multiple values single statement/execution
c.execute('SELECT * FROM stocks WHERE symbol=? OR symbol=?', ('RHAT', 'MSO'))
print c.fetchall()
c.execute('SELECT * FROM stocks WHERE symbol IN (?, ?)', ('RHAT', 'MSO'))
print c.fetchall()
# This also works, though ones above are better as a habit as it's inline with syntax of executemany().. but your choice.
c.execute('SELECT * FROM stocks WHERE symbol=? OR symbol=?', 'RHAT', 'MSO')
print c.fetchall()
# Insert a single item
c.execute('INSERT INTO stocks VALUES (?,?,?,?,?)', ('2006-03-28', 'BUY', 'IBM', 1000, 45.00))

How can I selectively merge or pick changes from another branch in Git?

A simple approach for selective merging/committing by file:

git checkout dstBranch
git merge srcBranch

// Make changes, including resolving conflicts to single files
git add singleFile1 singleFile2
git commit -m "message specific to a few files"
git reset --hard # Blow away uncommitted changes

Inserting image into IPython notebook markdown

I put the IPython notebook in the same folder with the image. I use Windows. The image name is "phuong huong xac dinh.PNG".

In Markdown:

<img src="phuong huong xac dinh.PNG">

Code:

from IPython.display import Image
Image(filename='phuong huong xac dinh.PNG')

git: How to ignore all present untracked files?

-u no doesn't show unstaged files either. -uno works as desired and shows unstaged, but hides untracked.

Visual Studio 2013 error MS8020 Build tools v140 cannot be found

That's the platform toolset for VS2015. You uninstalled it, therefore it is no longer available.

To change your Platform Toolset:

  1. Right click your project, go to Properties.
  2. Under Configuration Properties, go to General.
  3. Change your Platform Toolset to one of the available ones.

Why "Data at the root level is invalid. Line 1, position 1." for XML Document?

if you are using XDocument.Load(url); to fetch xml from another domain, it's possible that the host will reject the request and return and unexpected (non-xml) result, which results in the above XmlException

See my solution to this eventuality here: XDocument.Load(feedUrl) returns "Data at the root level is invalid. Line 1, position 1."

Configure Flask dev server to be visible across the network

Add below lines to your project

if __name__ == '__main__':
    app.debug = True
    app.run(host = '0.0.0.0',port=5005)

belongs_to through associations

You can also delegate:

class Company < ActiveRecord::Base
  has_many :employees
  has_many :dogs, :through => :employees
end

class Employee < ActiveRescord::Base
  belongs_to :company
  has_many :dogs
end

class Dog < ActiveRecord::Base
  belongs_to :employee

  delegate :company, :to => :employee, :allow_nil => true
end

How to convert CSV to JSON in Node.js

Node-ETL package is enough for all BI processing.

npm install node-etl; 

Then :

var ETL=require('node-etl');
var output=ETL.extract('./data.csv',{
              headers:["a","b","c","d"],
              ignore:(line,index)=>index!==0, //ignore first line
 });

PHP date() with timezone?

I have created this very straightforward function, and it works like a charm:

function ts2time($timestamp,$timezone){ /* input: 1518404518,America/Los_Angeles */            
        $date = new DateTime(date("d F Y H:i:s",$timestamp));
        $date->setTimezone(new DateTimeZone($timezone));
        $rt=$date->format('M d, Y h:i:s a'); /* output: Feb 11, 2018 7:01:58 pm */
        return $rt;
    }

Add Marker function with Google Maps API

<div id="map" style="width:100%;height:500px"></div>

<script>
function myMap() {
  var myCenter = new google.maps.LatLng(51.508742,-0.120850);
  var mapCanvas = document.getElementById("map");
  var mapOptions = {center: myCenter, zoom: 5};
  var map = new google.maps.Map(mapCanvas, mapOptions);
  var marker = new google.maps.Marker({position:myCenter});
  marker.setMap(map);
}
</script>

<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyBu-916DdpKAjTmJNIgngS6HL_kDIKU0aU&callback=myMap"></script>

How do I solve the INSTALL_FAILED_DEXOPT error?

Your old version of the app that you are installing has dependent libraries / jars that have been changed. I ran into this issue when updating other jar files that my app was refrencing.

You will need to Uninstall your old version and then you should have no more issues...

Settings-->Applications-->Manage Applications-->[Find and Uninstall your App]

INSTALL_FAILED_DEXOPT errors should not erupt. Like

[2011-06-14 01:23:40 - ProtectYourself] Installing ProtectYourself.apk...
[2011-06-14 01:24:26 - ProtectYourself] Installation error: INSTALL_FAILED_DEXOPT
[2011-06-14 01:24:26 - ProtectYourself] Please check logcat output for more details.
[2011-06-14 01:24:26 - ProtectYourself] Launch canceled!

Whoo hoo.

Python unittest passing arguments

Have a same problem. My solution is after you handle with parsing arguments using argparse or other way, remove arguments from sys.argv

sys.argv = sys.argv[:1]  

If you need you can filter unittest arguments from main.parseArgs()

Drop view if exists

Regarding the error

'CREATE VIEW' must be the first statement in a query batch.

Microsoft SQL Server has a quirky reqirement that CREATE VIEW be the only statement in a batch. This is also true of a few other statements, such as CREATE FUNCTION. It is not true of CREATE TABLE, so go figure …

The solution is to send your script to the server in small batches. One way to do this is to select a single statement and execute it. This is clearly inconvenient.

The more convenient solution is to get the client to send the script in small isolated batches.

The GO keyword is not strictly an SQL command, which is why you can’t end it with a semicolon like real SQL commands. Instead it is an instruction to the client to break the script at this point and to send the portion as a batch.

As a result, you end up writing something like:

DROP VIEW IF EXISTS … ;
GO
CREATE VIEW … AS … ;
GO

None of the other database servers I have encountered (PostgreSQL, MySQL, Oracle, SQLite) have this quirk, so the requirement appears to be Microsoft Only.

How to define and use function inside Jenkins Pipeline config?

Solved! The call build job: project, parameters: params fails with an error java.lang.UnsupportedOperationException: must specify $class with an implementation of interface java.util.List when params = [:]. Replacing it with params = null solved the issue. Here the working code below.

def doCopyMibArtefactsHere(projectName) {
    step ([
        $class: 'CopyArtifact',
        projectName: projectName,
        filter: '**/**.mib',
        fingerprintArtifacts: true, 
        flatten: true
    ]);
}

def BuildAndCopyMibsHere(projectName, params = null) {
    build job: project, parameters: params
    doCopyMibArtefactsHere(projectName)
}
node { 
    stage('Prepare Mib'){
        BuildAndCopyMibsHere('project1')
    }
}

How can I capture the right-click event in JavaScript?

I think that you are looking for something like this:

   function rightclick() {
    var rightclick;
    var e = window.event;
    if (e.which) rightclick = (e.which == 3);
    else if (e.button) rightclick = (e.button == 2);
    alert(rightclick); // true or false, you can trap right click here by if comparison
}

(http://www.quirksmode.org/js/events_properties.html)

And then use the onmousedown even with the function rightclick() (if you want to use it globally on whole page you can do this <body onmousedown=rightclick(); >

Switch in Laravel 5 - Blade

IN LARAVEL 5.2 AND UP:

Write your usual code between the opening and closing PHP statements.

@php
switch (x) {
    case 1:
        //code to be executed
        break;
    default:
        //code to be executed
}
@endphp

How do I use the Simple HTTP client in Android?

You can use this code:

int count;
            try {
                URL url = new URL(f_url[0]);
                URLConnection conection = url.openConnection();
                conection.setConnectTimeout(TIME_OUT);
                conection.connect();
                // Getting file length
                int lenghtOfFile = conection.getContentLength();
                // Create a Input stream to read file - with 8k buffer
                InputStream input = new BufferedInputStream(url.openStream(),
                        8192);
                // Output stream to write file
                OutputStream output = new FileOutputStream(
                        "/sdcard/9androidnet.jpg");

                byte data[] = new byte[1024];
                long total = 0;
                while ((count = input.read(data)) != -1) {
                    total += count;
                    // publishing the progress....
                    // After this onProgressUpdate will be called
                    publishProgress("" + (int) ((total * 100) / lenghtOfFile));
                    // writing data to file
                    output.write(data, 0, count);
                }
                // flushing output
                output.flush();
                // closing streams
                output.close();
                input.close();
            } catch (SocketTimeoutException e) {
                connectionTimeout=true;
            } catch (Exception e) {
                Log.e("Error: ", e.getMessage());
            }

Escape double quotes in parameter

Another way to escape quotes (though probably not preferable), which I've found used in certain places is to use multiple double-quotes. For the purpose of making other people's code legible, I'll explain.

Here's a set of basic rules:

  1. When not wrapped in double-quoted groups, spaces separate parameters:
    program param1 param2 param 3 will pass four parameters to program.exe:
         param1, param2, param, and 3.
  2. A double-quoted group ignores spaces as value separators when passing parameters to programs:
    program one two "three and more" will pass three parameters to program.exe:
         one, two, and three and more.
  3. Now to explain some of the confusion:
  4. Double-quoted groups that appear directly adjacent to text not wrapped with double-quotes join into one parameter:
    hello"to the entire"world acts as one parameter: helloto the entireworld.
  5. Note: The previous rule does NOT imply that two double-quoted groups can appear directly adjacent to one another.
  6. Any double-quote directly following a closing quote is treated as (or as part of) plain unwrapped text that is adjacent to the double-quoted group, but only one double-quote:
    "Tim says, ""Hi!""" will act as one parameter: Tim says, "Hi!"

Thus there are three different types of double-quotes: quotes that open, quotes that close, and quotes that act as plain-text.
Here's the breakdown of that last confusing line:

"   open double-quote group
T   inside ""s
i   inside ""s
m   inside ""s
    inside ""s - space doesn't separate
s   inside ""s
a   inside ""s
y   inside ""s
s   inside ""s
,   inside ""s
    inside ""s - space doesn't separate
"   close double-quoted group
"   quote directly follows closer - acts as plain unwrapped text: "
H   outside ""s - gets joined to previous adjacent group
i   outside ""s - ...
!   outside ""s - ...
"   open double-quote group
"   close double-quote group
"   quote directly follows closer - acts as plain unwrapped text: "

Thus, the text effectively joins four groups of characters (one with nothing, however):
Tim says,  is the first, wrapped to escape the spaces
"Hi! is the second, not wrapped (there are no spaces)
 is the third, a double-quote group wrapping nothing
" is the fourth, the unwrapped close quote.

As you can see, the double-quote group wrapping nothing is still necessary since, without it, the following double-quote would open up a double-quoted group instead of acting as plain-text.

From this, it should be recognizable that therefore, inside and outside quotes, three double-quotes act as a plain-text unescaped double-quote:

"Tim said to him, """What's been happening lately?""""

will print Tim said to him, "What's been happening lately?" as expected. Therefore, three quotes can always be reliably used as an escape.
However, in understanding it, you may note that the four quotes at the end can be reduced to a mere two since it technically is adding another unnecessary empty double-quoted group.

Here are a few examples to close it off:

program a b                       REM sends (a) and (b)
program """a"""                   REM sends ("a")
program """a b"""                 REM sends ("a) and (b")
program """"Hello,""" Mike said." REM sends ("Hello," Mike said.)
program ""a""b""c""d""            REM sends (abcd) since the "" groups wrap nothing
program "hello to """quotes""     REM sends (hello to "quotes")
program """"hello world""         REM sends ("hello world")
program """hello" world""         REM sends ("hello world")
program """hello "world""         REM sends ("hello) and (world")
program "hello ""world"""         REM sends (hello "world")
program "hello """world""         REM sends (hello "world")

Final note: I did not read any of this from any tutorial - I came up with all of it by experimenting. Therefore, my explanation may not be true internally. Nonetheless all the examples above evaluate as given, thus validating (but not proving) my theory.

I tested this on Windows 7, 64bit using only *.exe calls with parameter passing (not *.bat, but I would suppose it works the same).

git error: failed to push some refs to remote

git push origin {your_local_branch}:{your_remote_branch}

If your local branch and remote branch share the same name, then can you omit your local branch name, just use git push {your_remote_branch}. Otherwise it will throw this error.

Vertically align text next to an image?

Not sure as to why it doesn't render it on your navigation's browser, but I normally use an snippet like this when trying to display a header with an image and a centered text, hope it helps!

https://output.jsbin.com/jeqorahupo

            <hgroup style="display:block; text-align:center;  vertical-align:middle;  margin:inherit auto; padding:inherit auto; max-height:inherit">

            <header style="background:url('http://lorempixel.com/30/30/') center center no-repeat; background-size:auto; display:inner-block; vertical-align:middle; position:relative; position:absolute; top:inherit; left:inherit; display: -webkit-box; display: -webkit-flex;display: -moz-box;display: -ms-flexbox;display: flex;-webkit-flex-align: center;-ms-flex-align: center;-webkit-align-items: center;align-items: center;">

            <image src="http://lorempixel.com/60/60/" title="Img title" style="opacity:0.35"></img>
                    http://lipsum.org</header>
                    </hgroup>

jquery: get id from class selector

$(".class").click(function(){
    alert($(this).attr('id'));
});

only on jquery button click we can do this class should be written there

Best practice to call ConfigureAwait for all server-side code

Brief answer to your question: No. You shouldn't call ConfigureAwait(false) at the application level like that.

TL;DR version of the long answer: If you are writing a library where you don't know your consumer and don't need a synchronization context (which you shouldn't in a library I believe), you should always use ConfigureAwait(false). Otherwise, the consumers of your library may face deadlocks by consuming your asynchronous methods in a blocking fashion. This depends on the situation.

Here is a bit more detailed explanation on the importance of ConfigureAwait method (a quote from my blog post):

When you are awaiting on a method with await keyword, compiler generates bunch of code in behalf of you. One of the purposes of this action is to handle synchronization with the UI (or main) thread. The key component of this feature is the SynchronizationContext.Current which gets the synchronization context for the current thread. SynchronizationContext.Current is populated depending on the environment you are in. The GetAwaiter method of Task looks up for SynchronizationContext.Current. If current synchronization context is not null, the continuation that gets passed to that awaiter will get posted back to that synchronization context.

When consuming a method, which uses the new asynchronous language features, in a blocking fashion, you will end up with a deadlock if you have an available SynchronizationContext. When you are consuming such methods in a blocking fashion (waiting on the Task with Wait method or taking the result directly from the Result property of the Task), you will block the main thread at the same time. When eventually the Task completes inside that method in the threadpool, it is going to invoke the continuation to post back to the main thread because SynchronizationContext.Current is available and captured. But there is a problem here: the UI thread is blocked and you have a deadlock!

Also, here are two great articles for you which are exactly for your question:

Finally, there is a great short video from Lucian Wischik exactly on this topic: Async library methods should consider using Task.ConfigureAwait(false).

Hope this helps.

No resource found that matches the given name: attr 'android:keyboardNavigationCluster'. when updating to Support Library 26.0.0

//Adding this to the root build.gradle solved my problem, thanks @Yalamber
subprojects {
        afterEvaluate { project ->
            if (project.hasProperty("android")) {
                android {
                    compileSdkVersion 26
                    buildToolsVersion '26.0.2'
                }
            }
        }
    }

Play audio from a stream using C#

I've always used FMOD for things like this because it's free for non-commercial use and works well.

That said, I'd gladly switch to something that's smaller (FMOD is ~300k) and open-source. Super bonus points if it's fully managed so that I can compile / merge it with my .exe and not have to take extra care to get portability to other platforms...

(FMOD does portability too but you'd obviously need different binaries for different platforms)

C/C++ switch case with string

The best way is to use source generation, so that you could use

if (hash(str) == HASH("some string") ..

in your main source, and an pre-build step would convert the HASH(const char*) expression to an integer value.

Android: How do I get string from resources using its name?

Best Approach

App.getRes().getString(R.string.some_id)

Will work Everywhere (Utils, Models also).

I have read all the answers, all answers can make your work done.

  • You can use getString(R.string.some_string_id) in both Activity or Fragment.
  • You can use Context.getString(R.string.some_string_id) where you don't have direct access to getString() method. Like Dialog.

Problem

When you don't have Context access, like a method in your Util class.

Assume below method without Context.

public void someMethod(){
    ...
    // can't use getResource() or getString() without Context.
}

Now you will pass Context as a parameter in this method and use getString().

public void someMethod(Context context){
    ...
    context.getString(R.string.some_id);
}

What i do is

public void someMethod(){
    ...
    App.getAppResources().getString(R.string.some_id)
}

What? It is very simple to use anywhere in your app!

So here is a solution by which you can access resources from anywhere like Util class .

import android.app.Application;
import android.content.res.Resources;

public class App extends Application {
    private static Resources resources;

    @Override
    public void onCreate() {
        super.onCreate();

        resources = getResources();
    }

    public static Resources getAppResources() {
        return resources;
    }

}

Add name field to your manifest.xml <application tag.

<application
        android:name=".App"
        ...
        >
        ...
    </application>

Now you are good to go. Use App.getAppResources().getString(R.string.some_id) anywhere in app.

PostgreSQL ERROR: canceling statement due to conflict with recovery

I'm going to add some updated info and references to @max-malysh's excellent answer above.

In short, if you do something on the master, it needs to be replicated on the slave. Postgres uses WAL records for this, which are sent after every logged action on the master to the slave. The slave then executes the action and the two are again in sync. In one of several scenarios, you can be in conflict on the slave with what's coming in from the master in a WAL action. In most of them, there's a transaction happening on the slave which conflicts with what the WAL action wants to change. In that case, you have two options:

  1. Delay the application of the WAL action for a bit, allowing the slave to finish its conflicting transaction, then apply the action.
  2. Cancel the conflicting query on the slave.

We're concerned with #1, and two values:

  • max_standby_archive_delay - this is the delay used after a long disconnection between the master and slave, when the data is being read from a WAL archive, which is not current data.
  • max_standby_streaming_delay - delay used for cancelling queries when WAL entries are received via streaming replication.

Generally, if your server is meant for high availability replication, you want to keep these numbers short. The default setting of 30000 (milliseconds if no units given) is sufficient for this. If, however, you want to set up something like an archive, reporting- or read-replica that might have very long-running queries, then you'll want to set this to something higher to avoid cancelled queries. The recommended 900s setting above seems like a good starting point. I disagree with the official docs on setting an infinite value -1 as being a good idea--that could mask some buggy code and cause lots of issues.

The one caveat about long-running queries and setting these values higher is that other queries running on the slave in parallel with the long-running one which is causing the WAL action to be delayed will see old data until the long query has completed. Developers will need to understand this and serialize queries which shouldn't run simultaneously.

For the full explanation of how max_standby_archive_delay and max_standby_streaming_delay work and why, go here.

Difference between javacore, thread dump and heap dump in Websphere

JVM head dump is a snapshot of a JVM heap memory in a given time. So its simply a heap representation of JVM. That is the state of the objects.

JVM thread dump is a snapshot of a JVM threads at a given time. So thats what were threads doing at any given time. This is the state of threads. This helps understanding such as locked threads, hanged threads and running threads.

Head dump has more information of java class level information than a thread dump. For example Head dump is good to analyse JVM heap memory issues and OutOfMemoryError errors. JVM head dump is generated automatically when there is something like OutOfMemoryError has taken place. Heap dump can be created manually by killing the process using kill -3 . Generating a heap dump is a intensive computing task, which will probably hang your jvm. so itsn't a methond to use offetenly. Heap can be analysed using tools such as eclipse memory analyser.

Core dump is a os level memory usage of objects. It has more informaiton than a head dump. core dump is not created when we kill a process purposely.

"Unorderable types: int() < str()"

Just a side note, in Python 2.0 you could compare anything to anything (int to string). As this wasn't explicit, it was changed in 3.0, which is a good thing as you are not running into the trouble of comparing senseless values with each other or when you forget to convert a type.

What is the point of the diamond operator (<>) in Java 7?

When you write List<String> list = new LinkedList();, compiler produces an "unchecked" warning. You may ignore it, but if you used to ignore these warnings you may also miss a warning that notifies you about a real type safety problem.

So, it's better to write a code that doesn't generate extra warnings, and diamond operator allows you to do it in convenient way without unnecessary repetition.

How to override !important?

The !important should only be used when you have selectors in your style sheet with conflicting specificity.

But even when you have conflicting specificity, it is better to create a more specific selector for the exception. In your case it's better to have a class in your HTML which you can use to create a more specific selector which doesn't need the !important rule.

td.a-semantic-class-name { height: 100px; }

I personally never use !important in my style sheets. Remember that the C in CSS is for cascading. Using !important will break this.

SQL Update with row_number()

With UpdateData  As
(
SELECT RS_NOM,
ROW_NUMBER() OVER (ORDER BY [RS_NOM] DESC) AS RN
FROM DESTINATAIRE_TEMP
)
UPDATE DESTINATAIRE_TEMP SET CODE_DEST = RN
FROM DESTINATAIRE_TEMP
INNER JOIN UpdateData ON DESTINATAIRE_TEMP.RS_NOM = UpdateData.RS_NOM

When should we use Observer and Observable?

Observer a.k.a callback is registered at Observable.

It is used for informing e.g. about events that happened at some point of time. It is widely used in Swing, Ajax, GWT for dispatching operations on e.g. UI events (button clicks, textfields changed etc).

In Swing you find methods like addXXXListener(Listener l), in GWT you have (Async)callbacks.

As list of observers is dynamic, observers can register and unregister during runtime. It is also a good way do decouple observable from observers, as interfaces are used.

The matching wildcard is strict, but no declaration can be found for element 'context:component-scan

This error can also be caused if the jar file that contains the XSD you require is not included in your deployed class path.

Make sure the dependencies are available in your container.

How to style child components from parent component's CSS file?

Since /deep/, >>>, and ::ng-deep are all deprecated. The best approach is to use the following in your child component styling

:host-context(.theme-light) h2 {
  background-color: #eef;
}

This will look for the theme-light in any of the ancestors of your child component. See docs here: https://angular.io/guide/component-styles#host-context

nginx- duplicate default server error

OS Debian 10 + nginx. In my case, i unlinked the "default" page as:

  1. cd/etc/nginx/sites-enabled
  2. unlink default
  3. service nginx restart

How do I pull from a Git repository through an HTTP proxy?

You can also set the HTTP proxy that Git uses in global configuration property http.proxy:

git config --global http.proxy http://proxy.mycompany:80

To authenticate with the proxy:

git config --global http.proxy http://mydomain\\myusername:mypassword@myproxyserver:8080/

(Credit goes to @EugeneKulabuhov and @JaimeReynoso for the authentication format.)

How to run bootRun with spring profile via gradle task

For anyone looking how to do this in Kotlin DSL, here's a working example for build.gradle.kts:

tasks.register("bootRunDev") {
    group = "application"
    description = "Runs this project as a Spring Boot application with the dev profile"
    doFirst {
        tasks.bootRun.configure {
            systemProperty("spring.profiles.active", "dev")
        }
    }
    finalizedBy("bootRun")
}

jQuery - prevent default, then continue default

With jQuery and a small variation of @Joepreludian's answer above:

Important points to keep in mind:

  • .one(...) instead on .on(...) or .submit(...)
  • named function instead of anonymous function since we will be referring it within the callback.

$('form#my-form').one('submit', function myFormSubmitCallback(evt) {
    evt.stopPropagation();
    evt.preventDefault();
    var $this = $(this);
    if (allIsWell) {
        $this.submit(); // submit the form and it will not re-enter the callback because we have worked with .one(...)
    } else {
        $this.one('submit', myFormSubmitCallback); // lets get into the callback 'one' more time...
    }
});

You can change the value of allIsWell variable in the below snippet to true or false to test the functionality:

_x000D_
_x000D_
$('form#my-form').one('submit', function myFormSubmitCallback(evt){_x000D_
  evt.stopPropagation();_x000D_
  evt.preventDefault();_x000D_
  var $this = $(this);_x000D_
  var allIsWell = $('#allIsWell').get(0).checked;_x000D_
  if(allIsWell) {_x000D_
    $this.submit();_x000D_
  } else {_x000D_
    $this.one('submit', myFormSubmitCallback);_x000D_
  }_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<form action="/" id="my-form">_x000D_
  <input name="./fname" value="John" />_x000D_
  <input name="./lname" value="Smith" />_x000D_
  <input type="submit" value="Lets Do This!" />_x000D_
  <br>_x000D_
  <label>_x000D_
    <input type="checkbox" value="true" id="allIsWell" />_x000D_
    All Is Well_x000D_
  </label>_x000D_
</form>
_x000D_
_x000D_
_x000D_

Good Luck...

Cannot execute script: Insufficient memory to continue the execution of the program

sqlcmd -S mamxxxxxmu\sqlserverr -U sa -P x1123 -d QLDB -i D:\qldbscript.sql

  • Open command prompt in run as administrator

  • enter above command

"mamxxxxxmu" is computer name "sqlserverr" is server name "sa" is username of server "x1123" is password of server "QLDB" is database name "D:\qldbscript.sql" is sql script file to execute in database

How can I delete a service in Windows?

Here is a vbs script that was passed down to me:

Set servicelist = GetObject("winmgmts:").InstancesOf ("Win32_Service")

for each service in servicelist
    sname = lcase(service.name)
    If sname = "NameOfMyService" Then 
        msgbox(sname)
        service.delete ' the internal name of your service
    end if
next

Delete multiple rows by selecting checkboxes using PHP

Delete Multiple checkbox using PHP Code

<input type="checkbox" name="chkbox[]  value=".$row[0]."/>
<input type="submit" name="delete" value="delete"/>
<?php
if(isset($_POST['delete']))
{
 $cnt=array();
 $cnt=count($_POST['chkbox']);
 for($i=0;$i<$cnt;$i++)
  {
     $del_id=$_POST['chkbox'][$i];
     $query="delete from $tablename where Id=".$del_id;
     mysql_query($query);
  }
}

Node.js res.setHeader('content-type', 'text/javascript'); pushing the response javascript as file download

You can directly set the content type like below:

res.writeHead(200, {'Content-Type': 'text/plain'});

For reference go through the nodejs Docs link.

css divide width 100% to 3 column

.selector{width:calc(100% / 3);}

How to error handle 1004 Error with WorksheetFunction.VLookup?

There is a way to skip the errors inside the code and go on with the loop anyway, hope it helps:

Sub new1()

Dim wsFunc As WorksheetFunction: Set wsFunc = Application.WorksheetFunction
Dim ws As Worksheet: Set ws = Sheets(1)
Dim rngLook As Range: Set rngLook = ws.Range("A:M")

currName = "Example"
On Error Resume Next ''if error, the code will go on anyway
cellNum = wsFunc.VLookup(currName, rngLook, 13, 0)

If Err.Number <> 0 Then
''error appeared
    MsgBox "currName not found" ''optional, no need to do anything
End If

On Error GoTo 0 ''no error, coming back to default conditions

End Sub

How to inflate one view with a layout

I had the hardest time with this error, because of my unique circumstances, but finally found a solution.

My situation: I am using a separate view (XML) which holds a WebView, then opens in an AlertDialog when I click a button in my main activity view. But somehow or another the WebView belonged to the main activity view (probably because I pull the resource from here), so right before I assigned it to my AlertDialog (as a view), I had to get the parent of my WebView, put it into a ViewGroup, then remove all the views on that ViewGroup. This worked, and my error went away.

// set up Alert Dialog box
AlertDialog.Builder alert = new AlertDialog.Builder(this);
// inflate other xml where WebView is
LayoutInflater layoutInflater = (LayoutInflater)this.getSystemService
                (Context.LAYOUT_INFLATER_SERVICE);
View v = layoutInflater.inflate(R.layout.your_webview_layout, null);
final WebView webView = (WebView) v.findViewById(R.id.your_webview_id);

// more code...

.... later on after I loaded my WebView ....

// first, remove the parent of WebView from it's old parent so can be assigned a new one.
ViewGroup vg = (ViewGroup) webView.getParent();
vg.removeAllViews();

// put WebView in Dialog box
alert.setView(webView);
alert.show();

ActionBarActivity cannot resolve a symbol

Follow the steps mentioned for using support ActionBar in Android Studio(0.4.2) :

Download the Android Support Repository from Android SDK Manager, SDK Manager icon will be available on Android Studio tool bar (or Tools -> Android -> SDK Manager).

enter image description here

After download you will find your Support repository here

$SDK_DIR\extras\android\m2repository\com\android\support\appcompat-v7

Open your main module's build.gradle file and add following dependency for using action bar in lower API level

dependencies {
    compile 'com.android.support:appcompat-v7:+'
}

Sync your project with gradle using the tiny Gradle icon available in toolbar (or Tools -> Android -> Sync Project With Gradle Files).

There is some issue going on with Android Studio 0.4.2 so check this as well if you face any issue while importing classes in code.

Import Google Play Services library in Android Studio

If Required follow the steps as well :

  • Exit Android Studio
  • Delete all the .iml files and files inside .idea folder from your project
  • Relaunch Android Studio and wait till the project synced completely with gradle. If it shows an error in Event Log with import option click on Import Project.

This is bug in Android Studio 0.4.2 and fixed for Android Studio 0.4.3 release.

Can't create handler inside thread which has not called Looper.prepare()

The error is self-explanatory... doInBackground() runs on a background thread which, since it is not intended to loop, is not connected to a Looper.

You most likely don't want to directly instantiate a Handler at all... whatever data your doInBackground() implementation returns will be passed to onPostExecute() which runs on the UI thread.

   mActivity = ThisActivity.this; 

    mActivity.runOnUiThread(new Runnable() {
     public void run() {
     new asyncCreateText().execute();
     }
   });

ADDED FOLLOWING THE STACKTRACE APPEARING IN QUESTION:

Looks like you're trying to start an AsyncTask from a GL rendering thread... don't do that cos they won't ever Looper.loop() either. AsyncTasks are really designed to be run from the UI thread only.

The least disruptive fix would probably be to call Activity.runOnUiThread() with a Runnable that kicks off your AsyncTask.

C++ equivalent of Java's toString?

You can also do it this way, allowing polymorphism:

class Base {
public:
   virtual std::ostream& dump(std::ostream& o) const {
      return o << "Base: " << b << "; ";
   }
private:
  int b;
};

class Derived : public Base {
public:
   virtual std::ostream& dump(std::ostream& o) const {
      return o << "Derived: " << d << "; ";
   }
private:
   int d;
}

std::ostream& operator<<(std::ostream& o, const Base& b) { return b.dump(o); }

Rails: Adding an index after adding column

If you need to create a user_id then it would be a reasonable assumption that you are referencing a user table. In which case the migration shall be:

rails generate migration AddUserRefToProducts user:references

This command will generate the following migration:

class AddUserRefToProducts < ActiveRecord::Migration
  def change
    add_reference :user, :product, index: true
  end
end

After running rake db:migrate both a user_id column and an index will be added to the products table.

In case you just need to add an index to an existing column, e.g. name of a user table, the following technique may be helpful:

rails generate migration AddIndexToUsers name:string:index will generate the following migration:

class AddIndexToUsers < ActiveRecord::Migration
  def change
    add_column :users, :name, :string
    add_index :users, :name
  end
end

Delete add_column line and run the migration.

In the case described you could have issued rails generate migration AddIndexIdToTable index_id:integer:index command and then delete add_column line from the generated migration. But I'd rather recommended to undo the initial migration and add reference instead:

rails generate migration RemoveUserIdFromProducts user_id:integer
rails generate migration AddUserRefToProducts user:references

How to get the <html> tag HTML with JavaScript / jQuery?

This is how to get the html DOM element purely with JS:

var htmlElement = document.getElementsByTagName("html")[0];

or

var htmlElement = document.querySelector("html");

And if you want to use jQuery to get attributes from it...

$(htmlElement).attr(INSERT-ATTRIBUTE-NAME);

Convert to Datetime MM/dd/yyyy HH:mm:ss in Sql Server

Declare @month as char(2)
Declare @date as char(2)
Declare @year as char(4)
declare @time as char(8)
declare @customdate as varchar(20)

set @month = MONTH(GetDate());
set @date = Day(GetDate());
set @year = year(GetDate());

set @customdate= @month+'/'+@date+'/'+@year+' '+ CONVERT(varchar(8), GETDATE(),108);
print(@customdate)

How can I clear an HTML file input with JavaScript?

Try this easy and it works

let input = elem.querySelector('input[type="file"]');
input.outerHTML=input.outerHTML;

this will reset the input

Converting a date string to a DateTime object using Joda Time library

tl;dr

java.time.LocalDateTime.parse( 
    "04/02/2011 20:27:05" , 
    DateTimeFormatter.ofPattern( "dd/MM/uuuu HH:mm:ss" )
)

java.time

The modern approach uses the java.time classes that supplant the venerable Joda-Time project.

Parse as a LocalDateTime as your input lacks any indicator of time zone or offset-from-UTC.

String input = "04/02/2011 20:27:05" ;
DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd/MM/uuuu HH:mm:ss" ) ;
LocalDateTime ldt = LocalDateTime.parse( input , f ) ;

ldt.toString(): 2011-02-04T20:27:05

Tip: Where possible, use the standard ISO 8601 formats when exchanging date-time values as text rather than format seen here. Conveniently, the java.time classes use the standard formats when parsing/generating strings.


About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

How to add new column to MYSQL table?

for WORDPRESS:

global $wpdb;


$your_table  = $wpdb->prefix. 'My_Table_Name';
$your_column =                'My_Column_Name'; 

if (!in_array($your_column, $wpdb->get_col( "DESC " . $your_table, 0 ) )){  $result= $wpdb->query(
    "ALTER     TABLE $your_table     ADD $your_column     VARCHAR(100)     CHARACTER SET utf8     NOT NULL     "  //you can add positioning phraze: "AFTER My_another_column"
);}

Getting query parameters from react-router hash fragment

After reading the other answers (First by @duncan-finney and then by @Marrs) I set out to find the change log that explains the idiomatic react-router 2.x way of solving this. The documentation on using location (which you need for queries) in components is actually contradicted by the actual code. So if you follow their advice, you get big angry warnings like this:

Warning: [react-router] `context.location` is deprecated, please use a route component's `props.location` instead.

It turns out that you cannot have a context property called location that uses the location type. But you can use a context property called loc that uses the location type. So the solution is a small modification on their source as follows:

const RouteComponent = React.createClass({
    childContextTypes: {
        loc: PropTypes.location
    },

    getChildContext() {
        return { location: this.props.location }
    }
});

const ChildComponent = React.createClass({
    contextTypes: {
        loc: PropTypes.location
    },
    render() {
        console.log(this.context.loc);
        return(<div>this.context.loc.query</div>);
    }
});

You could also pass down only the parts of the location object you want in your children get the same benefit. It didn't change the warning to change to the object type. Hope that helps.

What is phtml, and when should I use a .phtml extension rather than .php?

It is a file ext that some folks used for a while to denote that it was PHP generated HTML. As servers like Apache don't care what you use as a file ext as long as it is mapped to something, you could go ahead and call all your PHP files .jimyBobSmith and it would happily run them. PHTML just happened to be a trend that caught on for a while.

Controlling fps with requestAnimationFrame?

I suggest wrapping your call to requestAnimationFrame in a setTimeout:

const fps = 25;
function animate() {
  // perform some animation task here

  setTimeout(() => {
    requestAnimationFrame(animate);
  }, 1000 / fps);
}
animate();

You need to call requestAnimationFrame from within setTimeout, rather than the other way around, because requestAnimationFrame schedules your function to run right before the next repaint, and if you delay your update further using setTimeout you will have missed that time window. However, doing the reverse is sound, since you’re simply waiting a period of time before making the request.

Jquery UI datepicker. Disable array of Dates

beforeShowDate didn't work for me, so I went ahead and developed my own solution:

$('#embeded_calendar').datepicker({
               minDate: date,
                localToday:datePlusOne,
               changeDate: true,
               changeMonth: true,
               changeYear: true,
               yearRange: "-120:+1",
               onSelect: function(selectedDateFormatted){

                     var selectedDate = $("#embeded_calendar").datepicker('getDate');

                    deactivateDates(selectedDate);
                   }

           });


              var excludedDates = [ "10-20-2017","10-21-2016", "11-21-2016"];

              deactivateDates(new Date());

            function deactivateDates(selectedDate){
                setTimeout(function(){ 
                      var thisMonthExcludedDates = thisMonthDates(selectedDate);
                      thisMonthExcludedDates = getDaysfromDate(thisMonthExcludedDates);
                       var excludedTDs = page.find('td[data-handler="selectDay"]').filter(function(){
                           return $.inArray( $(this).text(), thisMonthExcludedDates) >= 0
                       });

                       excludedTDs.unbind('click').addClass('ui-datepicker-unselectable');
                   }, 10);
            }

            function thisMonthDates(date){
              return $.grep( excludedDates, function( n){
                var dateParts = n.split("-");
                return dateParts[0] == date.getMonth() + 1  && dateParts[2] == date.getYear() + 1900;
            });
            }

            function getDaysfromDate(datesArray){
                  return  $.map( datesArray, function( n){
                    return n.split("-")[1]; 
                });
             }

MySQL command line client for Windows

You can access mySQL in command line just by typing:

C:\www\mysql\bin> mysql -u root -p

After which you can type sql commands normally such as:

mysql> SHOW DATABASES;

Here, I am assuming you mySQL installation directory is C:\www\mysql.

Merge unequal dataframes and replace missing rows with 0

Or, as an alternative to @Chase's code, being a recent plyr fan with a background in databases:

require(plyr)
zz<-join(df1, df2, type="left")
zz[is.na(zz)] <- 0

How can I run dos2unix on an entire directory?

for FILE in /var/www/html/files/*
do
 /usr/bin/dos2unix FILE
done

How do you decompile a swf file

I've used Sothink SWF decompiler a couple of times, the only problem is that as project gets more complex, the output of decompiler gets harder to compile back again. But it ensures that you can get your .as files most of the time, compilable fla is a question.

Sothink SWF Decompiler

sql server convert date to string MM/DD/YYYY

select convert(varchar(10), cast(fmdate as date), 101) from sery

Without cast I was not getting fmdate converted, so fmdate was a string.

Add column to dataframe with constant value

You can use insert to specify where you want to new column to be. In this case, I use 0 to place the new column at the left.

df.insert(0, 'Name', 'abc')

  Name        Date  Open  High  Low  Close
0  abc  01-01-2015   565   600  400    450

Getting user input

In python 3.x, use input() instead of raw_input()

How do I access Configuration in any class in ASP.NET Core?

I'm doing it like this at the moment:

// Requires NuGet package Microsoft.Extensions.Configuration.Json

using Microsoft.Extensions.Configuration;
using System.IO;

namespace ImagesToMssql.AppsettingsJson
{
    public static class AppSettingsJson
    {           
        public static IConfigurationRoot GetAppSettings()
        {
            string applicationExeDirectory = ApplicationExeDirectory();

            var builder = new ConfigurationBuilder()
            .SetBasePath(applicationExeDirectory)
            .AddJsonFile("appsettings.json");

            return builder.Build();
        }

        private static string ApplicationExeDirectory()
        {
            var location = System.Reflection.Assembly.GetExecutingAssembly().Location;
            var appRoot = Path.GetDirectoryName(location);

            return appRoot;
        }
    }
}

And then I use this where I need to get the data from the appsettings.json file:

var appSettingsJson = AppSettingsJson.GetAppSettings();
// appSettingsJson["keyName"]

How to downgrade to older version of Gradle

I did following steps to downgrade Gradle back to the original version:

  • I deleted content of '.gradle/caches' folder in user home directory (windows).
  • I deleted content of '.gradle' folder in my project root.
  • I checked that Gradle version is properly set in 'Project' option of 'Project Structure' in Android Studio.
  • I selected 'Use default gradle wrapper' option in 'Settings' in Android Studio, just search for gradle key word to find it.

Probably last step is enough as in my case the path to the new Gradle distribution was hardcoded there under 'Gradle home' option.

Npm Please try using this command again as root/administrator

What helped me on Windows 10 was just ticking off "Read Only" of project node_modules.

Git: How to update/checkout a single file from remote origin master?

Or git stash (if you have changes) on the branch you're on, checkout master, pull for the latest changes, grab that file to your desktop (or the entire app). Checkout the branch you were on. Git stash apply back to the state you were at, then fix the changes manually or drag it replacing the file.

This way is not sooooo cool but it def works if you guys can't figure anything else out.

Missing XML comment for publicly visible type or member

Insert an XML comment. ;-)

/// <summary>
/// Describe your member here.
/// </summary>
public string Something
{
    get;
    set;
}

This may appear like a joke at the first glance, but it may actually be useful. For me it turned out to be helpful to think about what methods do even for private methods (unless really trivial, of course).

Taking inputs with BufferedReader in Java

You can't read individual integers in a single line separately using BufferedReader as you do using Scannerclass. Although, you can do something like this in regard to your query :

import java.io.*;
class Test
{
   public static void main(String args[])throws IOException
    {
       BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
       int t=Integer.parseInt(br.readLine());
       for(int i=0;i<t;i++)
       {
         String str=br.readLine();
         String num[]=br.readLine().split(" ");
         int num1=Integer.parseInt(num[0]);
         int num2=Integer.parseInt(num[1]);
         //rest of your code
       }
    }
}

I hope this will help you.

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

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

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

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

Normalize columns of pandas data frame

If you like using the sklearn package, you can keep the column and index names by using pandas loc like so:

from sklearn.preprocessing import MinMaxScaler

scaler = MinMaxScaler() 
scaled_values = scaler.fit_transform(df) 
df.loc[:,:] = scaled_values

REST API - why use PUT DELETE POST GET?

You asked:

wouldn't it be easier to just accept JSON object through normal $_POST and then respond in JSON as well

From the Wikipedia on REST:

RESTful applications maximize the use of the pre-existing, well-defined interface and other built-in capabilities provided by the chosen network protocol, and minimize the addition of new application-specific features on top of it

From what (little) I've seen, I believe this is usually accomplished by maximizing the use of existing HTTP verbs, and designing a URL scheme for your service that is as powerful and self-evident as possible.

Custom data protocols (even if they are built on top of standard ones, such as SOAP or JSON) are discouraged, and should be minimized to best conform to the REST ideology.

SOAP RPC over HTTP, on the other hand, encourages each application designer to define a new and arbitrary vocabulary of nouns and verbs (for example getUsers(), savePurchaseOrder(...)), usually overlaid onto the HTTP 'POST' verb. This disregards many of HTTP's existing capabilities such as authentication, caching and content type negotiation, and may leave the application designer re-inventing many of these features within the new vocabulary.

The actual objects you are working with can be in any format. The idea is to reuse as much of HTTP as possible to expose your operations the user wants to perform on those resource (queries, state management/mutation, deletion).

You asked:

Am I missing something?

There is a lot more to know about REST and the URI syntax/HTTP verbs themselves. For example, some of the verbs are idempotent, others aren't. I didn't see anything about this in your question, so I didn't bother trying to dive into it. The other answers and Wikipedia both have a lot of good information.

Also, there is a lot to learn about the various network technologies built on top of HTTP that you can take advantage of if you're using a truly restful API. I'd start with authentication.

How to re-index all subarray elements of a multidimensional array?

PHP native function exists for this. See http://php.net/manual/en/function.reset.php

Simply do this: mixed reset ( array &$array )

How to access the value of a promise?

This example I find self-explanatory. Notice how await waits for the result and so you miss the Promise being returned.

cryA = crypto.subtle.generateKey({name:'ECDH', namedCurve:'P-384'}, true, ["deriveKey", "deriveBits"])
Promise {<pending>}
cryB = await crypto.subtle.generateKey({name:'ECDH', namedCurve:'P-384'}, true, ["deriveKey", "deriveBits"])
{publicKey: CryptoKey, privateKey: CryptoKey}

How do I get to IIS Manager?

You need to make sure the IIS Management Console is installed.

How can I include null values in a MIN or MAX?

Use the analytic function :

select case when 
    max(field) keep (dense_rank first order by datfin desc nulls first) is null then 1 
    else 0 end as flag 
from MYTABLE;

How to copy files from 'assets' folder to sdcard?

Use AssetManager, it allows to read the files in the assets. Then use regular Java IO to write the files to sdcard.

Google is your friend, search for an example.

Detect user scroll down or scroll up in jQuery

To differentiate between scroll up/down in jQuery, you could use:

var mousewheelevt = (/Firefox/i.test(navigator.userAgent)) ? "DOMMouseScroll" : "mousewheel" //FF doesn't recognize mousewheel as of FF3.x
$('#yourDiv').bind(mousewheelevt, function(e){

    var evt = window.event || e //equalize event object     
    evt = evt.originalEvent ? evt.originalEvent : evt; //convert to originalEvent if possible               
    var delta = evt.detail ? evt.detail*(-40) : evt.wheelDelta //check for detail first, because it is used by Opera and FF

    if(delta > 0) {
        //scroll up
    }
    else{
        //scroll down
    }   
});

This method also works in divs that have overflow:hidden.

I successfully tested it in FireFox, IE and Chrome.

Jquery change background color

The .css() function doesn't queue behind running animations, it's instantaneous.

To match the behaviour that you're after, you'd need to do the following:

$(document).ready(function() {
  $("button").mouseover(function() {
    var p = $("p#44.test").css("background-color", "yellow");
    p.hide(1500).show(1500);
    p.queue(function() {
      p.css("background-color", "red");
    });
  });
});

The .queue() function waits for running animations to run out and then fires whatever's in the supplied function.

How to test that no exception is thrown?

Java 8 makes this a lot easier, and Kotlin/Scala doubly so.

We can write a little utility class

class MyAssertions{
  public static void assertDoesNotThrow(FailingRunnable action){
    try{
      action.run()
    }
    catch(Exception ex){
      throw new Error("expected action not to throw, but it did!", ex)
    }
  }
}

@FunctionalInterface interface FailingRunnable { void run() throws Exception }

and then your code becomes simply:

@Test
public void foo(){
  MyAssertions.assertDoesNotThrow(() -> {
    //execute code that you expect not to throw Exceptions.
  }
}

If you dont have access to Java-8, I would use a painfully old java facility: aribitrary code blocks and a simple comment

//setup
Component component = new Component();

//act
configure(component);

//assert 
/*assert does not throw*/{
  component.doSomething();
}

And finally, with kotlin, a language I've recently fallen in love with:

fun (() -> Any?).shouldNotThrow() 
    = try { invoke() } catch (ex : Exception){ throw Error("expected not to throw!", ex) }

@Test fun `when foo happens should not throw`(){

  //...

  { /*code that shouldn't throw*/ }.shouldNotThrow()
}

Though there is a lot of room to fiddle with exactly how you want to express this, I was always a fan of fluent assertions.


Regarding

You're approaching this the wrong way. Just test your functionality: if an exception is thrown the test will automatically fail. If no exception is thrown, your tests will all turn up green.

This is correct in principle but incorrect in conclusion.

Java allows exceptions for flow of control. This is done by the JRE runtime itself in APIs like Double.parseDouble via a NumberFormatException and Paths.get via a InvalidPathException.

Given you've written a component that validates Number strings for Double.ParseDouble, maybe using a Regex, maybe a hand-written parser, or perhaps something that embeds some other domain rules that restricts the range of a double to something specific, how best to test this component? I think an obvious test would be to assert that, when the resulting string is parsed, no exception is thrown. I would write that test using either the above assertDoesNotThrow or /*comment*/{code} block. Something like

@Test public void given_validator_accepts_string_result_should_be_interpretable_by_doubleParseDouble(){
  //setup
  String input = "12.34E+26" //a string double with domain significance

  //act
  boolean isValid = component.validate(input)

  //assert -- using the library 'assertJ', my personal favourite 
  assertThat(isValid).describedAs(input + " was considered valid by component").isTrue();
  assertDoesNotThrow(() -> Double.parseDouble(input));
}

I would also encourage you to parameterize this test on input using Theories or Parameterized so that you can more easily re-use this test for other inputs. Alternatively, if you want to go exotic, you could go for a test-generation tool (and this). TestNG has better support for parameterized tests.

What I find particularly disagreeable is the recommendation of using @Test(expectedException=IllegalArgumentException.class), this exception is dangerously broad. If your code changes such that the component under test's constructor has if(constructorArgument <= 0) throw IllegalArgumentException(), and your test was supplying 0 for that argument because it was convenient --and this is very common, because good generating test data is a surprisingly hard problem--, then your test will be green-bar even though it tests nothing. Such a test is worse than useless.

Detecting request type in PHP (GET, POST, PUT or DELETE)

You can get any query string data i.e www.example.com?id=2&name=r

You must get data using $_GET['id'] or $_REQUEST['id'].

Post data means like form <form action='' method='POST'> you must use $_POST or $_REQUEST.

Check if a number is odd or even in python

Use the modulo operator:

if wordLength % 2 == 0:
    print "wordLength is even"
else:
    print "wordLength is odd"

For your problem, the simplest is to check if the word is equal to its reversed brother. You can do that with word[::-1], which create the list from word by taking every character from the end to the start:

def is_palindrome(word):
    return word == word[::-1]

How to create an Array, ArrayList, Stack and Queue in Java?

I am guessing you're confused with the parameterization of the types:

// This works, because there is one class/type definition in the parameterized <> field
ArrayList<String> myArrayList = new ArrayList<String>(); 


// This doesn't work, as you cannot use primitive types here
ArrayList<char> myArrayList = new ArrayList<char>();

How to remove focus border (outline) around text/input boxes? (Chrome)

Solution

*:focus {
    outline: 0;
}

PS: Use outline:0 instead of outline:none on focus. It's valid and better practice.

How to display a readable array - Laravel

You can use var_dump or print_r functions on Blade themplate via Controller functions :

class myController{

   public function showView(){
     return view('myView',["myController"=>$this]);
   }
   public function myprint($obj){
     echo "<pre>";
     print_r($obj);
     echo "</pre>";
   }
}

And use your blade themplate :

$myController->myprint($users);

Write to text file without overwriting in Java

JFileChooser c= new JFileChooser();
c.showOpenDialog(c);
File write_file = c.getSelectedFile();
String Content = "put here the data to be wriiten";
try
    {
    FileWriter fw = new FileWriter(write_file);
    BufferedWriter bw = new BufferedWriter(fw);
    bw.append(Content);
    bw.append("hiiiii");
    bw.close();
    fw.close();
    }
catch(Exception e)
   {
    System.out.println(e);
   `}

What is an application binary interface (ABI)?

I was also trying to understand ABI and JesperE’s answer was very helpful.

From a very simple perspective, we may try to understand ABI by considering binary compatibility.

KDE wiki defines a library as binary compatible “if a program linked dynamically to a former version of the library continues running with newer versions of the library without the need to recompile.” For more on dynamic linking, refer Static linking vs dynamic linking

Now, let’s try to look at just the most basic aspects needed for a library to be binary compatibility (assuming there are no source code changes to the library):

  1. Same/backward compatible instruction set architecture (processor instructions, register file structure, stack organization, memory access types, along with sizes, layout, and alignment of basic data types the processor can directly access)
  2. Same calling conventions
  3. Same name mangling convention (this might be needed if say a Fortran program needs to call some C++ library function).

Sure, there are many other details but this is mostly what the ABI also covers.

More specifically to answer your question, from the above, we can deduce:

ABI functionality: binary compatibility

existing entities: existing program/libraries/OS

consumer: libraries, OS

Hope this helps!

Is it possible to sort a ES6 map object?

One way is to get the entries array, sort it, and then create a new Map with the sorted array:

let ar = [...myMap.entries()];
sortedArray = ar.sort();
sortedMap = new Map(sortedArray);

But if you don't want to create a new object, but to work on the same one, you can do something like this:

// Get an array of the keys and sort them
let keys = [...myMap.keys()];
sortedKeys = keys.sort();

sortedKeys.forEach((key)=>{
  // Delete the element and set it again at the end
  const value = this.get(key);
  this.delete(key);
  this.set(key,value);
})

Pan & Zoom Image

@Anothen and @Number8 - The Vector class is not available in Silverlight, so to make it work we just need to keep a record of the last position sighted the last time the MouseMove event was called, and compare the two points to find the difference; then adjust the transform.

XAML:

    <Border Name="viewboxBackground" Background="Black">
            <Viewbox Name="viewboxMain">
                <!--contents go here-->
            </Viewbox>
    </Border>  

Code-behind:

    public Point _mouseClickPos;
    public bool bMoving;


    public MainPage()
    {
        InitializeComponent();
        viewboxMain.RenderTransform = new CompositeTransform();
    }

    void MouseMoveHandler(object sender, MouseEventArgs e)
    {

        if (bMoving)
        {
            //get current transform
            CompositeTransform transform = viewboxMain.RenderTransform as CompositeTransform;

            Point currentPos = e.GetPosition(viewboxBackground);
            transform.TranslateX += (currentPos.X - _mouseClickPos.X) ;
            transform.TranslateY += (currentPos.Y - _mouseClickPos.Y) ;

            viewboxMain.RenderTransform = transform;

            _mouseClickPos = currentPos;
        }            
    }

    void MouseClickHandler(object sender, MouseButtonEventArgs e)
    {
        _mouseClickPos = e.GetPosition(viewboxBackground);
        bMoving = true;
    }

    void MouseReleaseHandler(object sender, MouseButtonEventArgs e)
    {
        bMoving = false;
    }

Also note that you don't need a TransformGroup or collection to implement pan and zoom; instead, a CompositeTransform will do the trick with less hassle.

I'm pretty sure this is really inefficient in terms of resource usage, but at least it works :)

Trim to remove white space

No need for jQuery

JavaScript does have a native .trim() method.

var name = "    John Smith  ";
name = name.trim();

console.log(name); // "John Smith"

Example Here

String.prototype.trim()

The trim() method removes whitespace from both ends of a string. Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).

Set multiple system properties Java command line

If the required properties need to set in system then there is no option than -D But if you need those properties while bootstrapping an application then loading properties through the properties files is a best option. It will not require to change build for a single property.

How to validate domain name in PHP?

With this you will not only be checking if the domain has a valid format, but also if it is active / has an IP address assigned to it.

$domain = "stackoverflow.com";

if(filter_var(gethostbyname($domain), FILTER_VALIDATE_IP))
{
    return TRUE;
}

Note that this method requires the DNS entries to be active so if you require a domain string to be validated without being in the DNS use the regular expression method given by velcrow above.

Also this function is not intended to validate a URL string use FILTER_VALIDATE_URL for that. We do not use FILTER_VALIDATE_URL for a domain because a domain string is not a valid URL.

How to convert a set to a list in python?

Python is a dynamically typed language, which means that you cannot define the type of the variable as you do in C or C++:

type variable = value

or

type variable(value)

In Python, you use coercing if you change types, or the init functions (constructors) of the types to declare a variable of a type:

my_set = set([1,2,3])
type my_set

will give you <type 'set'> for an answer.

If you have a list, do this:

my_list = [1,2,3]
my_set = set(my_list)

How do I start a program with arguments when debugging?

I would suggest using the directives like the following:

        static void Main(string[] args)
        {
#if DEBUG
            args = new[] { "A" };
#endif

            Console.WriteLine(args[0]);
        }

Good luck!

What is memoization and how can I use it in Python?

The other answers cover what it is quite well. I'm not repeating that. Just some points that might be useful to you.

Usually, memoisation is an operation you can apply on any function that computes something (expensive) and returns a value. Because of this, it's often implemented as a decorator. The implementation is straightforward and it would be something like this

memoised_function = memoise(actual_function)

or expressed as a decorator

@memoise
def actual_function(arg1, arg2):
   #body

Should I put input elements inside a label element?

As most people have said, both ways work indeed, but I think only the first one should. Being semantically strict, the label does not "contain" the input. In my opinion, containment (parent/child) relationship in the markup structure should reflect containment in the visual output. i.e., an element surrounding another one in the markup should be drawn around that one in the browser. According to this, the label should be the input's sibling, not it's parent. So option number two is arbitrary and confusing. Everyone that has read the Zen of Python will probably agree (Flat is better than nested, Sparse is better than dense, There should be one-- and preferably only one --obvious way to do it...).

Because of decisions like that from W3C and major browser vendors (allowing "whichever way you prefer to do it", instead of "do it the right way") is that the web is so messed up today and we developers have to deal with tangled and so diverse legacy code.

Extracting .jar file with command line

From the docs:

To extract the files from a jar file, use x, as in:

C:\Java> jar xf myFile.jar

To extract only certain files from a jar file, supply their filenames:

C:\Java> jar xf myFile.jar foo bar

The folder where jar is probably isn't C:\Java for you, on my Windows partition it's:

C:\Program Files (x86)\Java\jdk[some_version_here]\bin

Unless the location of jar is in your path environment variable, you'll have to specify the full path/run the program from inside the folder.

EDIT: Here's another article, specifically focussed on extracting JARs: http://docs.oracle.com/javase/tutorial/deployment/jar/unpack.html

How do I vertically center an H1 in a div?

you can achieve vertical aligning with display:table-cell:

#section1 {
    height: 90%; 
    text-align:center; 
    display:table;
    width:100%;
}

#section1 h1 {display:table-cell; vertical-align:middle}

Example

Update - CSS3

For an alternate way to vertical align, you can use the following css 3 which should be supported in all the latest browsers:

#section1 {
    height: 90%; 
    width:100%;
    display:flex;
    align-items: center;
    justify-content: center;
}

Updated fiddle

"Untrusted App Developer" message when installing enterprise iOS Application

In my case, i just change some step below with iOS 9.3 To solve this problem:

Settings -> General -> Device Management -> Developer app Choose your current developer account name. Taps Trust "Your developer account name" Taps "Trust" in pop up. Done

Add 2 hours to current time in MySQL?

This will also work

SELECT NAME 
FROM GEO_LOCATION
WHERE MODIFY_ON BETWEEN SYSDATE() - INTERVAL 2 HOUR AND SYSDATE()

Android Studio Emulator and "Process finished with exit code 0"

I also had the same problem.I fix this problem by editing Graphics of AVD. Tools > Androids > AVD Manager > Actions > Edit > Show Advance Settings > Graphics -> Software. I hope this solution help u!

How to set border on jPanel?

Swing has no idea what the preferred, minimum and maximum sizes of the GoBoard should be as you have no components inside of it for it to calculate based on, so it picks a (probably wrong) default. Since you are doing custom drawing here, you should implement these methods

Dimension getPreferredSize()
Dimension getMinumumSize()
Dimension getMaximumSize()

or conversely, call the setters for these methods.

Python-Requests close http connection

I came to this question looking to solve the "too many open files" error, but I am using requests.session() in my code. A few searches later and I came up with an answer on the Python Requests Documentation which suggests to use the with block so that the session is closed even if there are unhandled exceptions:

with requests.Session() as s:
    s.get('http://google.com')

If you're not using Session you can actually do the same thing: https://2.python-requests.org/en/master/user/advanced/#session-objects

with requests.get('http://httpbin.org/get', stream=True) as r:
    # Do something

No restricted globals

/* eslint no-restricted-globals:0 */

is another alternate approach

How to access local files of the filesystem in the Android emulator?

In addition to the accepted answer, if you are using Android Studio you can

  1. invoke Android Device Monitor,
  2. select the device in the Devices tab on the left,
  3. select File Explorer tab on the right,
  4. navigate to the file you want, and
  5. click the Pull a file from the device button to save it to your local file system

Taken from Working with an emulator or device's file system

Fastest way to implode an associative array with keys

What about this shorter, more transparent, yet more intuitive with array_walk

$attributes = array(
  'data-href'   => 'http://example.com',
  'data-width'  => '300',
  'data-height' => '250',
  'data-type'   => 'cover',
);

$args = "";
array_walk(
    $attributes, 
    function ($item, $key) use (&$args) {
        $args .= $key ." = '" . $item . "' ";  
    }
);
// output: 'data-href="http://example.com" data-width="300" data-height="250" data-type="cover"

How to fix "containing working copy admin area is missing" in SVN?

I added a directory to svn, then I accidentally deleted the .svn folder within.

I used

svn delete --keep-local folderName

to fix my problem.

Cannot start session without errors in phpMyAdmin

In my case it was the wrong ownership for /var/lib/php/session. I changed that to the Apache user and group (the user and group that the webserver runs as) and all was well.

Unzipping files

I wrote "Binary Tools for JavaScript", an open source project that includes the ability to unzip, unrar and untar: https://github.com/codedread/bitjs

Used in my comic book reader: https://github.com/codedread/kthoom (also open source).

HTH!

android: how to use getApplication and getApplicationContext from non activity / service class

Either pass in a Context (so you can access resources), or make the helper methods static.

What is the best way to implement constants in Java?

One of the way I do it is by creating a 'Global' class with the constant values and do a static import in the classes that need access to the constant.

Determining if a number is prime

//simple function to determine if a number is a prime number
//to state if it is a prime number


#include <iostream>

using namespace std;


int isPrime(int x);  //functioned defined after int main()


int main()
{
 int y;
    cout<<"enter value"<<endl;

    cin>>y;

    isPrime(y);    

  return 0;

 } //end of main function


//-------------function

  int isPrime(int x)
 {
   int counter =0;
     cout<<"factors of "<<x<<" are "<<"\n\n";    //print factors of the number

     for (int i =0; i<=x; i++)

     {
       for (int j =0; j<=x; j++)

         {
           if (i * j == x)      //check if the number has multiples;
                {

                  cout<<i<<" ,  ";  //output provided for the reader to see the
                                    // muliples
                  ++counter;        //counts the number of factors

                 }


          }


    }
  cout<<"\n\n";

  if(counter>2) 
     { 
      cout<<"value is not a prime number"<<"\n\n";
     }

  if(counter<=2)
     {
       cout<<"value is a prime number"<<endl;
     }
 }

Using a bitmask in C#

One other really good reason to use a bitmask vs individual bools is as a web developer, when integrating one website to another, we frequently need to send parameters or flags in the querystring. As long as all of your flags are binary, it makes it much simpler to use a single value as a bitmask than send multiple values as bools. I know there are otherways to send data (GET, POST, etc.), but a simple parameter on the querystring is most of the time sufficient for nonsensitive items. Try to send 128 bool values on a querystring to communicate with an external site. This also gives the added ability of not pushing the limit on url querystrings in browsers

git add remote branch

I am not sure if you are trying to create a remote branch from a local branch or vice versa, so I've outlined both scenarios as well as provided information on merging the remote and local branches.

Creating a remote called "github":

git remote add github git://github.com/jdoe/coolapp.git
git fetch github

List all remote branches:

git branch -r
  github/gh-pages
  github/master
  github/next
  github/pu

Create a new local branch (test) from a github's remote branch (pu):

git branch test github/pu
git checkout test

Merge changes from github's remote branch (pu) with local branch (test):

git fetch github
git checkout test
git merge github/pu

Update github's remote branch (pu) from a local branch (test):

git push github test:pu

Creating a new branch on a remote uses the same syntax as updating a remote branch. For example, create new remote branch (beta) on github from local branch (test):

git push github test:beta

Delete remote branch (pu) from github:

git push github :pu

How do I escape only single quotes?

I am not sure what exactly you are doing with your data, but you could always try:

$string = str_replace("'", "%27", $string);

I use this whenever strings are sent to a database for storage.

%27 is the encoding for the ' character, and it also helps to prevent disruption of GET requests if a single ' character is contained in a string sent to your server. I would replace ' with %27 in both JavaScript and PHP just in case someone tries to manually send some data to your PHP function.

To make it prettier to your end user, just run an inverse replace function for all data you get back from your server and replace all %27 substrings with '.

Happy injection avoiding!

Altering column size in SQL Server

Running ALTER COLUMN without mentioning attribute NOT NULL will result in the column being changed to nullable, if it is already not. Therefore, you need to first check if the column is nullable and if not, specify attribute NOT NULL. Alternatively, you can use the following statement which checks the nullability of column beforehand and runs the command with the right attribute.

IF COLUMNPROPERTY(OBJECT_ID('Employee', 'U'), 'Salary', 'AllowsNull')=0
    ALTER TABLE [Employee]
        ALTER COLUMN [Salary] NUMERIC(22,5) NOT NULL
ELSE        
    ALTER TABLE [Employee]
        ALTER COLUMN [Salary] NUMERIC(22,5) NULL

Should you use rgba(0, 0, 0, 0) or rgba(255, 255, 255, 0) for transparency in CSS?

I would recommend using rgba(255,255,255,0) because broken (newest) safari thinks that if you are using transparent or rgba(0,0,0,0) in linear-gradent you really mean gray, For more info please head to - What happens in Safari with the transparent color?

Disable copy constructor

If you don't mind multiple inheritance (it is not that bad, after all), you may write simple class with private copy constructor and assignment operator and additionally subclass it:

class NonAssignable {
private:
    NonAssignable(NonAssignable const&);
    NonAssignable& operator=(NonAssignable const&);
public:
    NonAssignable() {}
};

class SymbolIndexer: public Indexer, public NonAssignable {
};

For GCC this gives the following error message:

test.h: In copy constructor ‘SymbolIndexer::SymbolIndexer(const SymbolIndexer&)’:
test.h: error: ‘NonAssignable::NonAssignable(const NonAssignable&)’ is private

I'm not very sure for this to work in every compiler, though. There is a related question, but with no answer yet.

UPD:

In C++11 you may also write NonAssignable class as follows:

class NonAssignable {
public:
    NonAssignable(NonAssignable const&) = delete;
    NonAssignable& operator=(NonAssignable const&) = delete;
    NonAssignable() {}
};

The delete keyword prevents members from being default-constructed, so they cannot be used further in a derived class's default-constructed members. Trying to assign gives the following error in GCC:

test.cpp: error: use of deleted function
          ‘SymbolIndexer& SymbolIndexer::operator=(const SymbolIndexer&)’
test.cpp: note: ‘SymbolIndexer& SymbolIndexer::operator=(const SymbolIndexer&)’
          is implicitly deleted because the default definition would
          be ill-formed:

UPD:

Boost already has a class just for the same purpose, I guess it's even implemented in similar way. The class is called boost::noncopyable and is meant to be used as in the following:

#include <boost/core/noncopyable.hpp>

class SymbolIndexer: public Indexer, private boost::noncopyable {
};

I'd recommend sticking to the Boost's solution if your project policy allows it. See also another boost::noncopyable-related question for more information.

sh: react-scripts: command not found after running npm start

This error occurs when you Install package with npm install instead of yarn install or vice-versa.