React Native Error: ENOSPC: System limit for number of file watchers reached
I encountered this issue on a linuxmint distro. It appeared to have happened when there was so many folders and subfolders/files I added to the /public folder in my app. I applied this fix and it worked well...
$ echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf
change directory into the /etc folder:
cd /etc
then run this:
sudo systcl -p
You may have to close your terminal and npm start again to get it to work.
If this fails i recommend installing react-scripts globally and running your application directly with that.
$ npm i -g --save react-scripts
then instead of npm start run react-scripts start to run your application.
fatal: ambiguous argument 'origin': unknown revision or path not in the working tree
For those experiencing this error on CI/CD, adding the line below worked for me on my GitHub Actions CI/CD workflow right after running pip install pyflakes diff-cover:
git fetch origin master:refs/remotes/origin/master
This is a snippet of the solution from the diff-cover github repo:
Solution: diff-cover matches source files in the coverage XML report with source files in the git diff. For this reason, it's important that the relative paths to the files match. If you are using coverage.py to generate the coverage XML report, then make sure you run diff-cover from the same working directory.
I got the solution on the links below. It is a documented diff-cover error.
https://diff-cover.readthedocs.io/en/latest//README.html https://github.com/Bachmann1234/diff_cover/blob/master/README.rst
Hope this helps :-).
List all the files and folders in a Directory with PHP recursive function
This solution did the job for me. The RecursiveIteratorIterator lists all directories and files recursively but unsorted. The program filters the list and sorts it.
I'm sure there is a way to write this shorter; feel free to improve it. It is just a code snippet. You may want to pimp it to your purposes.
<?php
$path = '/pth/to/your/directories/and/files';
// an unsorted array of dirs & files
$files_dirs = iterator_to_array( new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path),RecursiveIteratorIterator::SELF_FIRST) );
echo '<html><body><pre>';
// create a new associative multi-dimensional array with dirs as keys and their files
$dirs_files = array();
foreach($files_dirs as $dir){
if(is_dir($dir) AND preg_match('/\/\.$/',$dir)){
$d = preg_replace('/\/\.$/','',$dir);
$dirs_files[$d] = array();
foreach($files_dirs as $file){
if(is_file($file) AND $d == dirname($file)){
$f = basename($file);
$dirs_files[$d][] = $f;
}
}
}
}
//print_r($dirs_files);
// sort dirs
ksort($dirs_files);
foreach($dirs_files as $dir => $files){
$c = substr_count($dir,'/');
echo str_pad(' ',$c,' ', STR_PAD_LEFT)."$dir\n";
// sort files
asort($files);
foreach($files as $file){
echo str_pad(' ',$c,' ', STR_PAD_LEFT)."|_$file\n";
}
}
echo '</pre></body></html>';
?>
Switching users inside Docker image to a non-root user
You should not use su in a dockerfile, however you should use the USER instruction in the Dockerfile.
At each stage of the Dockerfile build, a new container is created so any change you make to the user will not persist on the next build stage.
For example:
RUN whoami
RUN su test
RUN whoami
This would never say the user would be test as a new container is spawned on the 2nd whoami. The output would be root on both (unless of course you run USER beforehand).
If however you do:
RUN whoami
USER test
RUN whoami
You should see root then test.
Alternatively you can run a command as a different user with sudo with something like
sudo -u test whoami
But it seems better to use the official supported instruction.
Why does configure say no C compiler found when GCC is installed?
The below packages are also helps you,
yum install gcc glibc glibc-common gd gd-devel -y
Can someone explain how to implement the jQuery File Upload plugin?
You can use uploadify this is the best multiupload jquery plugin i have used.
The implementation is easy, the browser support is perfect.
Installing MySQL Python on Mac OS X
the below may be help.
brew install mysql-connector-c
CFLAGS =-I/usr/local/Cellar/mysql-connector-c/6.1.11/include pip install MySQL-python
brew unlink mysql-connector-c
jQuery "on create" event for dynamically-created elements
create a <select> with id , append it to document.. and call .combobox
var dynamicScript='<select id="selectid"><option value="1">...</option>.....</select>'
$('body').append(dynamicScript); //append this to the place your wanted.
$('#selectid').combobox(); //get the id and add .combobox();
this should do the trick.. you can hide the select if you want and after .combobox show it..or else use find..
$(document).find('select').combobox() //though this is not good performancewise
How to sort by dates excel?
It's actually really easy. Highlight the DATE column and make sure that its set as date in Excel. Highlight everything you want to change, Then go to [DATA]>[SORT]>[COLUMN] and set sorting by date. Hope it helps.
Select entries between dates in doctrine 2
EDIT: See the other answers for better solutions
The original newbie approaches that I offered were (opt1):
$qb->where("e.fecha > '" . $monday->format('Y-m-d') . "'");
$qb->andWhere("e.fecha < '" . $sunday->format('Y-m-d') . "'");
And (opt2):
$qb->add('where', "e.fecha between '2012-01-01' and '2012-10-10'");
That was quick and easy and got the original poster going immediately.
Hence the accepted answer.
As per comments, it is the wrong answer, but it's an easy mistake to make, so I'm leaving it here as a "what not to do!"
configure: error: C compiler cannot create executables
I just had this issue building react-native app when I try to install Pod. I had to export 2 variables:
export CC=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc
CPP='/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc -E'
Copy a file in a sane, safe and efficient way
For those who like boost:
boost::filesystem::path mySourcePath("foo.bar");
boost::filesystem::path myTargetPath("bar.foo");
// Variant 1: Overwrite existing
boost::filesystem::copy_file(mySourcePath, myTargetPath, boost::filesystem::copy_option::overwrite_if_exists);
// Variant 2: Fail if exists
boost::filesystem::copy_file(mySourcePath, myTargetPath, boost::filesystem::copy_option::fail_if_exists);
Note that boost::filesystem::path is also available as wpath for Unicode. And that you could also use
using namespace boost::filesystem
if you do not like those long type names
Calling a Sub and returning a value
You should be using a Property:
Private _myValue As String
Public Property MyValue As String
Get
Return _myValue
End Get
Set(value As String)
_myValue = value
End Set
End Property
Then use it like so:
MyValue = "Hello"
Console.write(MyValue)
How is TeamViewer so fast?
would take time to route through TeamViewer's servers (TeamViewer bypasses corporate Symmetric NATs by simply proxying traffic through their servers)
You'll find that TeamViewer rarely needs to relay traffic through their own servers. TeamViewer penetrates NAT and networks complicated by NAT using NAT traversal (I think it is UDP hole-punching, like Google's libjingle).
They do use their own servers to middle-man in order to do the handshake and connection set-up, but most of the time the relationship between client and server will be P2P (best case, when the hand-shake is successful). If NAT traversal fails, then TeamViewer will indeed relay traffic through its own servers.
I've only ever seen it do this when a client has been behind double-NAT, though.
Easiest way to detect Internet connection on iOS?
Sorry for replying too late but I hope this answer can help somebody in future.
Following is a small native C code snippet that can check internet connectivity without any extra class.
Add the following headers:
#include<unistd.h>
#include<netdb.h>
Code:
-(BOOL)isNetworkAvailable
{
char *hostname;
struct hostent *hostinfo;
hostname = "google.com";
hostinfo = gethostbyname (hostname);
if (hostinfo == NULL){
NSLog(@"-> no connection!\n");
return NO;
}
else{
NSLog(@"-> connection established!\n");
return YES;
}
}
Swift 3
func isConnectedToInternet() -> Bool {
let hostname = "google.com"
//let hostinfo = gethostbyname(hostname)
let hostinfo = gethostbyname2(hostname, AF_INET6)//AF_INET6
if hostinfo != nil {
return true // internet available
}
return false // no internet
}
Create the perfect JPA entity
I'll try to answer several key points: this is from long Hibernate/ persistence experience including several major applications.
Entity Class: implement Serializable?
Keys needs to implement Serializable. Stuff that's going to go in the HttpSession, or be sent over the wire by RPC/Java EE, needs to implement Serializable. Other stuff: not so much. Spend your time on what's important.
Constructors: create a constructor with all required fields of the entity?
Constructor(s) for application logic, should have only a few critical "foreign key" or "type/kind" fields which will always be known when creating the entity. The rest should be set by calling the setter methods -- that's what they're for.
Avoid putting too many fields into constructors. Constructors should be convenient, and give basic sanity to the object. Name, Type and/or Parents are all typically useful.
OTOH if application rules (today) require a Customer to have an Address, leave that to a setter. That is an example of a "weak rule". Maybe next week, you want to create a Customer object before going to the Enter Details screen? Don't trip yourself up, leave possibility for unknown, incomplete or "partially entered" data.
Constructors: also, package private default constructor?
Yes, but use 'protected' rather than package private. Subclassing stuff is a real pain when the necessary internals are not visible.
Fields/Properties
Use 'property' field access for Hibernate, and from outside the instance. Within the instance, use the fields directly. Reason: allows standard reflection, the simplest & most basic method for Hibernate, to work.
As for fields 'immutable' to the application -- Hibernate still needs to be able to load these. You could try making these methods 'private', and/or put an annotation on them, to prevent application code making unwanted access.
Note: when writing an equals() function, use getters for values on the 'other' instance! Otherwise, you'll hit uninitialized/ empty fields on proxy instances.
Protected is better for (Hibernate) performance?
Unlikely.
Equals/HashCode?
This is relevant to working with entities, before they've been saved -- which is a thorny issue. Hashing/comparing on immutable values? In most business applications, there aren't any.
A customer can change address, change the name of their business, etc etc -- not common, but it happens. Corrections also need to be possible to make, when the data was not entered correctly.
The few things that are normally kept immutable, are Parenting and perhaps Type/Kind -- normally the user recreates the record, rather than changing these. But these do not uniquely identify the entity!
So, long and short, the claimed "immutable" data isn't really. Primary Key/ ID fields are generated for the precise purpose, of providing such guaranteed stability & immutability.
You need to plan & consider your need for comparison & hashing & request-processing work phases when A) working with "changed/ bound data" from the UI if you compare/hash on "infrequently changed fields", or B) working with "unsaved data", if you compare/hash on ID.
Equals/HashCode -- if a unique Business Key is not available, use a non-transient UUID which is created when the entity is initialized
Yes, this is a good strategy when required. Be aware that UUIDs are not free, performance-wise though -- and clustering complicates things.
Equals/HashCode -- never refer to related entities
"If related entity (like a parent entity) needs to be part of the Business Key then add a non insertable, non updatable field to store the parent id (with the same name as the ManytoOne JoinColumn) and use this id in the equality check"
Sounds like good advice.
Hope this helps!
Do not want scientific notation on plot axis
You can use format or formatC to, ahem, format your axis labels.
For whole numbers, try
x <- 10 ^ (1:10)
format(x, scientific = FALSE)
formatC(x, digits = 0, format = "f")
If the numbers are convertable to actual integers (i.e., not too big), you can also use
formatC(x, format = "d")
How you get the labels onto your axis depends upon the plotting system that you are using.
How do I run a Python program in the Command Prompt in Windows 7?
On Windows you use C:\Python27\python.exe instead of python.
If you add C:\Python27 to your path, you can shorten it to just python.exe, but you do not need to do this.
Ruby on Rails: Where to define global constants?
Some options:
Using a constant:
class Card
COLOURS = ['white', 'blue', 'black', 'red', 'green', 'yellow'].freeze
end
Lazy loaded using class instance variable:
class Card
def self.colours
@colours ||= ['white', 'blue', 'black', 'red', 'green', 'yellow'].freeze
end
end
If it is a truly global constant (avoid global constants of this nature, though), you could also consider putting
a top-level constant in config/initializers/my_constants.rb for example.
How do I import CSV file into a MySQL table?
Yet another solution is to use csvsql tool from amazing csvkit suite.
Usage example:
csvsql --db mysql://$user:$password@localhost/$database --insert --tables $tablename $file
This tool can automatically infer the data types (default behavior), create table and insert the data into the created table. --overwrite option can be used to drop table if it already exists. --insert option — to populate the table from the file.
To install the suite
pip install csvkit
Prerequisites: python-dev, libmysqlclient-dev, MySQL-python
apt-get install python-dev libmysqlclient-dev
pip install MySQL-python
What is the simplest way to convert a Java string from all caps (words separated by underscores) to CamelCase (no word separators)?
static String toCamelCase(String s){
String[] parts = s.split("_");
String camelCaseString = "";
for (String part : parts){
camelCaseString = camelCaseString + toProperCase(part);
}
return camelCaseString;
}
static String toProperCase(String s) {
return s.substring(0, 1).toUpperCase() +
s.substring(1).toLowerCase();
}
Note: You need to add argument validation.
Why catch and rethrow an exception in C#?
My main reason for having code like:
try
{
//Some code
}
catch (Exception e)
{
throw;
}
is so I can have a breakpoint in the catch, that has an instantiated exception object. I do this a lot while developing/debugging. Of course, the compiler gives me a warning on all the unused e's, and ideally they should be removed before a release build.
They are nice during debugging though.
Globally catch exceptions in a WPF application?
AppDomain.UnhandledException Event
This event provides notification of uncaught exceptions. It allows the application to log information about the exception before the system default handler reports the exception to the user and terminates the application.
public App()
{
AppDomain currentDomain = AppDomain.CurrentDomain;
currentDomain.UnhandledException += new UnhandledExceptionEventHandler(MyHandler);
}
static void MyHandler(object sender, UnhandledExceptionEventArgs args)
{
Exception e = (Exception) args.ExceptionObject;
Console.WriteLine("MyHandler caught : " + e.Message);
Console.WriteLine("Runtime terminating: {0}", args.IsTerminating);
}
If the UnhandledException event is handled in the default application domain, it is raised there for any unhandled exception in any thread, no matter what application domain the thread started in. If the thread started in an application domain that has an event handler for UnhandledException, the event is raised in that application domain. If that application domain is not the default application domain, and there is also an event handler in the default application domain, the event is raised in both application domains.
For example, suppose a thread starts in application domain "AD1", calls a method in application domain "AD2", and from there calls a method in application domain "AD3", where it throws an exception. The first application domain in which the UnhandledException event can be raised is "AD1". If that application domain is not the default application domain, the event can also be raised in the default application domain.
How to get rows count of internal table in abap?
You can use the following function:
DESCRIBE TABLE <itab-Name> LINES <variable>
After the call, variable contains the number of rows of the internal table .
Is there a REAL performance difference between INT and VARCHAR primary keys?
At HauteLook, we changed many of our tables to use natural keys. We did experience a real-world increase in performance. As you mention, many of our queries now use less joins which makes the queries more performant. We will even use a composite primary key if it makes sense. That being said, some tables are just easier to work with if they have a surrogate key.
Also, if you are letting people write interfaces to your database, a surrogate key can be helpful. The 3rd party can rely on the fact that the surrogate key will change only in very rare circumstances.
What is the "right" way to iterate through an array in Ruby?
Trying to do the same thing consistently with arrays and hashes might just be a code smell, but, at the risk of my being branded as a codorous half-monkey-patcher, if you're looking for consistent behaviour, would this do the trick?:
class Hash
def each_pairwise
self.each { | x, y |
yield [x, y]
}
end
end
class Array
def each_pairwise
self.each_with_index { | x, y |
yield [y, x]
}
end
end
["a","b","c"].each_pairwise { |x,y|
puts "#{x} => #{y}"
}
{"a" => "Aardvark","b" => "Bogle","c" => "Catastrophe"}.each_pairwise { |x,y|
puts "#{x} => #{y}"
}
Why do people hate SQL cursors so much?
In Oracle PL/SQL cursors will not result in table locks and it is possible to use bulk-collecting/bulk-fetching.
In Oracle 10 the often used implicit cursor
for x in (select ....) loop
--do something
end loop;
fetches implicitly 100 rows at a time. Explicit bulk-collecting/bulk-fetching is also possible.
However PL/SQL cursors are something of a last resort, use them when you are unable to solve a problem with set-based SQL.
Another reason is parallelization, it is easier for the database to parallelize big set-based statements than row-by-row imperative code. It is the same reason why functional programming becomes more and more popular (Haskell, F#, Lisp, C# LINQ, MapReduce ...), functional programming makes parallelization easier. The number CPUs per computer is rising so parallelization becomes more and more an issue.
Is it possible to program iPhone in C++
First off, saying Objective-C is "insane" is humorous- I have the Bjarne Stroustrup C++ book sitting by my side which clocks in at 1020 pages. Apple's PDF on Objective-C is 141.
If you want to use UIKit it will be very, very difficult for you to do anything in C++. Any serious iPhone app that conforms to Apple's UI will need it's UI portions to be written in Objective-C. Only if you're writing an OpenGL game can you stick almost entirely to C/C++.
Single Form Hide on Startup
Why do it like that at all?
Why not just start like a console app and show the form when necessary? There's nothing but a few references separating a console app from a forms app.
No need in being greedy and taking the memory needed for the form when you may not even need it.
Joining two table entities in Spring Data JPA
For a typical example of employees owning one or more phones, see this wikibook section.
For your specific example, if you want to do a one-to-one relationship, you should change the next code in ReleaseDateType model:
@Column(nullable = true)
private Integer media_Id;
for:
@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name="CACHE_MEDIA_ID", nullable=true)
private CacheMedia cacheMedia ;
and in CacheMedia model you need to add:
@OneToOne(cascade=ALL, mappedBy="ReleaseDateType")
private ReleaseDateType releaseDateType;
then in your repository you should replace:
@Query("Select * from A a left join B b on a.id=b.id")
public List<ReleaseDateType> FindAllWithDescriptionQuery();
by:
//In this case a query annotation is not need since spring constructs the query from the method name
public List<ReleaseDateType> findByCacheMedia_Id(Integer id);
or by:
@Query("FROM ReleaseDateType AS rdt WHERE cm.rdt.cacheMedia.id = ?1") //This is using a named query method
public List<ReleaseDateType> FindAllWithDescriptionQuery(Integer id);
Or if you prefer to do a @OneToMany and @ManyToOne relation, you should change the next code in ReleaseDateType model:
@Column(nullable = true)
private Integer media_Id;
for:
@OneToMany(cascade=ALL, mappedBy="ReleaseDateType")
private List<CacheMedia> cacheMedias ;
and in CacheMedia model you need to add:
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name="RELEASE_DATE_TYPE_ID", nullable=true)
private ReleaseDateType releaseDateType;
then in your repository you should replace:
@Query("Select * from A a left join B b on a.id=b.id")
public List<ReleaseDateType> FindAllWithDescriptionQuery();
by:
//In this case a query annotation is not need since spring constructs the query from the method name
public List<ReleaseDateType> findByCacheMedias_Id(Integer id);
or by:
@Query("FROM ReleaseDateType AS rdt LEFT JOIN rdt.cacheMedias AS cm WHERE cm.id = ?1") //This is using a named query method
public List<ReleaseDateType> FindAllWithDescriptionQuery(Integer id);
How to add style from code behind?
Try this:
Html Markup
<asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="#">HyperLink</asp:HyperLink>
Code
using System.Drawing;
using System.Web.UI;
using System.Web.UI.WebControls;
protected void Page_Load(object sender, EventArgs e)
{
Style style = new Style();
style.ForeColor = Color.Green;
this.Page.Header.StyleSheet.CreateStyleRule(style, this, "#" + HyperLink1.ClientID + ":hover");
}
When should we use Observer and Observable?
You have a concrete example of a Student and a MessageBoard. The Student registers by adding itself to the list of Observers that want to be notified when a new Message is posted to the MessageBoard. When a Message is added to the MessageBoard, it iterates over its list of Observers and notifies them that the event occurred.
Think Twitter. When you say you want to follow someone, Twitter adds you to their follower list. When they sent a new tweet in, you see it in your input. In that case, your Twitter account is the Observer and the person you're following is the Observable.
The analogy might not be perfect, because Twitter is more likely to be a Mediator. But it illustrates the point.
How to capture a backspace on the onkeydown event
not sure if it works outside of firefox:
callback (event){
if (event.keyCode === event.DOM_VK_BACK_SPACE || event.keyCode === event.DOM_VK_DELETE)
// do something
}
}
if not, replace event.DOM_VK_BACK_SPACE with 8 and event.DOM_VK_DELETE with 46 or define them as constant (for better readability)
How does Python return multiple values from a function?
Whenever multiple values are returned from a function in python, does it always convert the multiple values to a list of multiple values and then returns it from the function??
I'm just adding a name and print the result that returns from the function. the type of result is 'tuple'.
class FigureOut:
first_name = None
last_name = None
def setName(self, name):
fullname = name.split()
self.first_name = fullname[0]
self.last_name = fullname[1]
self.special_name = fullname[2]
def getName(self):
return self.first_name, self.last_name, self.special_name
f = FigureOut()
f.setName("Allen Solly Jun")
name = f.getName()
print type(name)
I don't know whether you have heard about 'first class function'. Python is the language that has 'first class function'
I hope my answer could help you. Happy coding.
Controlling Maven final name of jar artifact
In my maven ee project I am using:
<build>
<finalName>shop</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>${maven.war.version}</version>
<configuration><webappDirectory>${project.build.directory}/${project.build.finalName} </webappDirectory>
</configuration>
</plugin>
</plugins>
</build>
gcloud command not found - while installing Google Cloud SDK
I had a very different story here that turned out to be caused by my Python virtual environments.
Somewhere in the middle of running curl https://sdk.cloud.google.com | bash, I was getting error:
~/google-cloud-sdk/install.sh
Welcome to the Google Cloud SDK!
pyenv: python2: command not found
The `python2' command exists in these Python versions:
2.7.14
miniconda2-latest
solution I've modified google-cloud-sdk/install.sh script:
# if CLOUDSDK_PYTHON is empty
if [ -z "$CLOUDSDK_PYTHON" ]; then
# if python2 exists then plain python may point to a version != 2
#if _cloudsdk_which python2 >/dev/null; then
# CLOUDSDK_PYTHON=python2
if _cloudsdk_which python2.7 >/dev/null; then
# this is what some OS X versions call their built-in Python
CLOUDSDK_PYTHON=python2.7
and was able to run the installation successfully.
However, I still need to activate my pyenv that has python2 command to run gcloud.
why so
If you look at the google-cloud-sdk/install.sh script, you'll see that it's actually checking for versions of Python in a very brute manner:
if [ -z "$CLOUDSDK_PYTHON" ]; then
# if python2 exists then plain python may point to a version != 2
if _cloudsdk_which python2 >/dev/null; then
CLOUDSDK_PYTHON=python2
However, on my machine python2 doesn't point to Python binary, neither returns null. So the installation crashed.
font-family is inherit. How to find out the font-family in chrome developer pane?
Your browser's default font-family will be inherited for that case.
You can check the browser default font in chrome: Settings > Web content > Customize fonts...
How to define a two-dimensional array?
If you want to be able to think it as a 2D array rather than being forced to think in term of a list of lists (much more natural in my opinion), you can do the following:
import numpy
Nx=3; Ny=4
my2Dlist= numpy.zeros((Nx,Ny)).tolist()
The result is a list (not a NumPy array), and you can overwrite the individual positions with numbers, strings, whatever.
How to read AppSettings values from a .json file in ASP.NET Core
I doubt this is good practice but it's working locally. I'll update this if it fails when I publish/deploy (to an IIS web service).
Step 1 - Add this assembly to the top of your class (in my case, controller class):
using Microsoft.Extensions.Configuration;
Step 2 - Add this or something like it:
var config = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json").Build();
Step 3 - Call your key's value by doing this (returns string):
config["NameOfYourKey"]
What is Turing Complete?
In the simplest terms, a Turing-complete system can solve any possible computational problem.
One of the key requirements is the scratchpad size be unbounded and that is possible to rewind to access prior writes to the scratchpad.
Thus in practice no system is Turing-complete.
Rather some systems approximate Turing-completeness by modeling unbounded memory and performing any possible computation that can fit within the system's memory.
Maven: Non-resolvable parent POM
I had similar problem at my work.
Building the parent project without dependency created parent_project.pom file in the .m2 folder.
Then add the child module in the parent POM and run Maven build.
<modules>
<module>module1</module>
<module>module2</module>
<module>module3</module>
<module>module4</module>
</modules>
Change background color of iframe issue
just building on what Chetabahana wrote, I found that adding a short delay to the JS function helped on a site I was working on. It meant that the function kicked in after the iframe loaded. You can play around with the delay.
var delayInMilliseconds = 500; // half a second
setTimeout(function() {
var iframe = document.getElementsByTagName('iframe')[0];
iframe.style.background = 'white';
iframe.contentWindow.document.body.style.backgroundColor = 'white';
}, delayInMilliseconds);
I hope this helps!
using where and inner join in mysql
Try this:
SELECT Locations.Name, Schools.Name
FROM Locations
INNER JOIN School_Locations ON School_Locations.Locations_Id = Locations.Id
INNER JOIN Schools ON School.Id = Schools_Locations.School_Id
WHERE Locations.Type = "coun"
You can join Locations to School_Locations and then School_Locations to School. This forms a set of all related Locations and Schools, which you can then widdle down using the WHERE clause to those whose Location is of type "coun."
How to get child element by index in Jquery?
There are the following way to select first child
1) $('.second div:first-child')
2) $('.second *:first-child')
3) $('div:first-child', '.second')
4) $('*:first-child', '.second')
5) $('.second div:nth-child(1)')
6) $('.second').children().first()
7) $('.second').children().eq(0)
How to run .APK file on emulator
Start an Android Emulator (make sure that all supported APIs are included when you created the emulator, we needed to have the Google APIs for instance).
Then simply email yourself a link to the .apk file, and download it directly in the emulator, and click the downloaded file to install it.
Vuejs: v-model array in multiple input
If you were asking how to do it in vue2 and make options to insert and delete it, please, have a look an js fiddle
new Vue({_x000D_
el: '#app',_x000D_
data: {_x000D_
finds: [] _x000D_
},_x000D_
methods: {_x000D_
addFind: function () {_x000D_
this.finds.push({ value: 'def' });_x000D_
},_x000D_
deleteFind: function (index) {_x000D_
console.log(index);_x000D_
console.log(this.finds);_x000D_
this.finds.splice(index, 1);_x000D_
}_x000D_
}_x000D_
});<script src="https://unpkg.com/[email protected]/dist/vue.js"></script>_x000D_
<div id="app">_x000D_
<h1>Finds</h1>_x000D_
<div v-for="(find, index) in finds">_x000D_
<input v-model="find.value">_x000D_
<button @click="deleteFind(index)">_x000D_
delete_x000D_
</button>_x000D_
</div>_x000D_
_x000D_
<button @click="addFind">_x000D_
New Find_x000D_
</button>_x000D_
_x000D_
<pre>{{ $data }}</pre>_x000D_
</div>How to convert WebResponse.GetResponseStream return into a string?
You should create a StreamReader around the stream, then call ReadToEnd.
You should consider calling WebClient.DownloadString instead.
IndexError: list index out of range and python
The way Python indexing works is that it starts at 0, so the first number of your list would be [0]. You would have to print[52], as the starting index is 0 and
therefore line 53 is [52].
Subtract 1 from the value and you should be fine. :)
How do I import a .bak file into Microsoft SQL Server 2012?
Using the RESTORE DATABASE command most likely. bak is a common extension used for a database backup file. You'll find documentation for this command on MSDN.
How to set the env variable for PHP?
Follow this for Windows operating system with WAMP installed.
System > Advanced System Settings > Environment Variables
Click new
Variable name : path
Variable value : c:\wamp\bin\php\php5.3.13\
Click ok
How to extract the year from a Python datetime object?
It's in fact almost the same in Python.. :-)
import datetime
year = datetime.date.today().year
Of course, date doesn't have a time associated, so if you care about that too, you can do the same with a complete datetime object:
import datetime
year = datetime.datetime.today().year
(Obviously no different, but you can store datetime.datetime.today() in a variable before you grab the year, of course).
One key thing to note is that the time components can differ between 32-bit and 64-bit pythons in some python versions (2.5.x tree I think). So you will find things like hour/min/sec on some 64-bit platforms, while you get hour/minute/second on 32-bit.
Font Awesome icon inside text input element
Building on allcaps suggestion. Here is the font-awesome background method with the least amount of HTML:
<div class="wrapper"><input></div>
.wrapper {
position: relative;
}
input { padding-left: 20px; }
.wrapper:before {
font-family: 'FontAwesome';
position: absolute;
top: 2px;
left: 3px;
content: "\f007";
}
jquery multiple checkboxes array
If you have a class for each of your input box, then you can do it as
var checked = []
$('input.Booking').each(function ()
{
checked.push($(this).val());
});
JavaFX Panel inside Panel auto resizing
If you are using Scene Builder, you will see at the right an accordion panel which normally has got three options ("Properties", "Layout" and "Code"). In the second one ("Layout"), you will see an option called "[parent layout] Constraints" (in your case "AnchorPane Constrainsts").
You should put "0" in the four sides of the element wich represents the parent layout.
Rotate label text in seaborn factorplot
I had a problem with the answer by @mwaskorn, namely that
g.set_xticklabels(rotation=30)
fails, because this also requires the labels. A bit easier than the answer by @Aman is to just add
plt.xticks(rotation=45)
CSS: Position loading indicator in the center of the screen
You can use this OnLoad or during fetch infos from DB
In HTML Add following code:
<div id="divLoading">
<p id="loading">
<img src="~/images/spinner.gif">
</p>
In CSS add following Code:
#divLoading {
margin: 0px;
display: none;
padding: 0px;
position: absolute;
right: 0px;
top: 0px;
width: 100%;
height: 100%;
background-color: rgb(255, 255, 255);
z-index: 30001;
opacity: 0.8;}
#loading {
position: absolute;
color: White;
top: 50%;
left: 45%;}
if you want to show and hide from JS:
document.getElementById('divLoading').style.display = 'none'; //Not Visible
document.getElementById('divLoading').style.display = 'block';//Visible
Making button go full-width?
The question was raised years ago, with the older version it was a little hard to get...but now this question has a very easy answer.
<div class="btn btn-outline-primary btn-block">Button text here</div>
Hide strange unwanted Xcode logs
This solution has been working for me:
- Run the app in the simulator
- Open the system log (
?+/)
This will dump out all of the debug data and also your NSLogs.
To filter just your NSLog statements:
- Prefix each with a symbol, for example:
NSLog(@"^ Test Log") - Filter the results using the search box on the top right, "^" in the case above
This is what you should get:
Understanding Bootstrap's clearfix class
When a clearfix is used in a parent container, it automatically wraps around all the child elements.
It is usually used after floating elements to clear the float layout.
When float layout is used, it will horizontally align the child elements. Clearfix clears this behaviour.
Example - Bootstrap Panels
In bootstrap, when the class panel is used, there are 3 child types: panel-header, panel-body, panel-footer. All of which have display:block layout but panel-body has a clearfix pre-applied. panel-body is a main container type whereas panel-header & panel-footer isn't intended to be a container, it is just intended to hold some basic text.
If floating elements are added, the parent container does not get wrapped around those elements because the height of floating elements is not inherited by the parent container.
So for panel-header & panel-footer, clearfix is needed to clear the float layout of elements: Clearfix class gives a visual appearance that the height of the parent container has been increased to accommodate all of its child elements.
<div class="container">
<div class="panel panel-default">
<div class="panel-footer">
<div class="col-xs-6">
<input type="button" class="btn btn-primary" value="Button1">
<input type="button" class="btn btn-primary" value="Button2">
<input type="button" class="btn btn-primary" value="Button3">
</div>
</div>
</div>
<div class="panel panel-default">
<div class="panel-footer">
<div class="col-xs-6">
<input type="button" class="btn btn-primary" value="Button1">
<input type="button" class="btn btn-primary" value="Button2">
<input type="button" class="btn btn-primary" value="Button3">
</div>
<div class="clearfix"/>
</div>
</div>
</div>
How to convert map to url query string?
Kotlin
mapOf(
"param1" to 12,
"param2" to "cat"
).map { "${it.key}=${it.value}" }
.joinToString("&")
What does "to stub" mean in programming?
A stub, in this context, means a mock implementation.
That is, a simple, fake implementation that conforms to the interface and is to be used for testing.
Unable to add window -- token null is not valid; is your activity running?
PopupWindow can only be attached to an Activity. In your case you are trying to add PopupWindow to service which is not right.
To solve this problem you can use a blank and transparent Activity. On click of floating icon, launch the Activity and on onCreate of Activity show the PopupWindow.
On dismiss of PopupWindow, you can finish the transparent Activity.
Hope this helps you.
String Padding in C
You must make sure that the input string has enough space to hold all the padding characters. Try this:
char hello[11] = "Hello";
StringPadRight(hello, 10, "0");
Note that I allocated 11 bytes for the hello string to account for the null terminator at the end.
Disable browser 'Save Password' functionality
Because autocomplete="off" does not work for password fields, one must rely on javascript. Here's a simple solution based on answers found here.
Add the attribute data-password-autocomplete="off" to your password field:
<input type="password" data-password-autocomplete="off">
Include the following JS:
$(function(){
$('[data-password-autocomplete="off"]').each(function() {
$(this).prop('type', 'text');
$('<input type="password"/>').hide().insertBefore(this);
$(this).focus(function() {
$(this).prop('type', 'password');
});
});
});
This solution works for both Chrome and FF.
How can I match multiple occurrences with a regex in JavaScript similar to PHP's preg_match_all()?
2020 edit
Use URLSearchParams, as this job no longer requires any kind of custom code. Browsers can do this for you with a single constructor:
const str = "1111342=Adam%20Franco&348572=Bob%20Jones";
const data = new URLSearchParams(str);
for (pair of data) console.log(pair)
yields
Array [ "1111342", "Adam Franco" ]
Array [ "348572", "Bob Jones" ]
So there is no reason to use regex for this anymore.
Original answer
If you don't want to rely on the "blind matching" that comes with running exec style matching, JavaScript does come with match-all functionality built in, but it's part of the replace function call, when using a "what to do with the capture groups" handling function:
var data = {};
var getKeyValue = function(fullPattern, group1, group2, group3) {
data[group2] = group3;
};
mystring.replace(/(?:&|&)?([^=]+)=([^&]+)/g, getKeyValue);
done.
Instead of using the capture group handling function to actually return replacement strings (for replace handling, the first arg is the full pattern match, and subsequent args are individual capture groups) we simply take the groups 2 and 3 captures, and cache that pair.
So, rather than writing complicated parsing functions, remember that the "matchAll" function in JavaScript is simply "replace" with a replacement handler function, and much pattern matching efficiency can be had.
How to show Page Loading div until the page has finished loading?
My blog will work 100 percent.
function showLoader()_x000D_
{_x000D_
$(".loader").fadeIn("slow");_x000D_
}_x000D_
function hideLoader()_x000D_
{_x000D_
$(".loader").fadeOut("slow");_x000D_
}.loader {_x000D_
position: fixed;_x000D_
left: 0px;_x000D_
top: 0px;_x000D_
width: 100%;_x000D_
height: 100%;_x000D_
z-index: 9999;_x000D_
background: url('pageLoader2.gif') 50% 50% no-repeat rgb(249,249,249);_x000D_
opacity: .8;_x000D_
}<div class="loader">A Generic error occurred in GDI+ in Bitmap.Save method
GDI+ exceptions occured due to below points
- Folder access issue
- Missing properties of images
If folder issue - please provide access to application If Missing properties then use below code
Code 1
using (Bitmap bmp = new Bitmap(webStream))
{
using (Bitmap newImage = new Bitmap(bmp))
{
newImage.Save("c:\temp\test.jpg", ImageFormat.Jpeg);
}
}
Code 2
using (Bitmap bmp = new Bitmap(webStream))
{
using (Bitmap newImage = new Bitmap(bmp))
{
newImage.SetResolution(bmp.HorizontalResolution, bmp.VerticalResolution);
Rectangle lockedRect = new Rectangle(0, 0, bmp.Width, bmp.Height);
BitmapData bmpData = newImage.LockBits(lockedRect, ImageLockMode.ReadWrite, bmp.PixelFormat);
bmpData.PixelFormat = bmp.PixelFormat;
newImage.UnlockBits(bmpData);
using (Graphics gr = Graphics.FromImage(newImage))
{
gr.SmoothingMode = SmoothingMode.HighQuality;
gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
}
foreach (var item in bmp.PropertyItems)
{
newImage.SetPropertyItem(item);
}
newImage.Save("c:\temp\test.jpg", ImageFormat.Jpeg);
}
}
Different between code 1 and code 2
Code - 1 : it will just create image and can open it on normal image viewer
- the image can't open in Photoshop
- Image size will be double
Code - 2 : to open image in image edition tools use code
by using code 1 it just create images but it not assign image marks.
H2 in-memory database. Table not found
<bean id="benchmarkDataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.h2.Driver" />
<property name="url" value="jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1" />
<property name="username" value="sa" />
<property name="password" value="" />
</bean>
How to allow users to check for the latest app version from inside the app?
I did using in-app updates. This will only with devices running Android 5.0 (API level 21) or higher,
_tkinter.TclError: no display name and no $DISPLAY environment variable
In order to see images, plots and anything displayed on windows on your remote machine you need to connect to it like this:
ssh -X user@hostname
That way you enable the access to the X server. The X server is a program in the X Window System that runs on local machines (i.e., the computers used directly by users) and handles all access to the graphics cards, display screens and input devices (typically a keyboard and mouse) on those computers.
More info here.
Update TensorFlow
Tensorflow upgrade -Python3
>> pip3 install --upgrade tensorflow --user
if you got this
"ERROR: tensorboard 2.0.2 has requirement grpcio>=1.24.3, but you'll have grpcio 1.22.0 which is incompatible."
Upgrade grpcio
>> pip3 install --upgrade grpcio --user
"Couldn't read dependencies" error with npm
Recently, I've started to get an error:
npm ERR! install Couldn't read dependencies
npm ERR! Error: Invalid version: "1.0"
So, you may need to specify version of your package with 3 numbers, e.g. 1.0.0 instead of 1.0 if you get similar error.
Get cart item name, quantity all details woocommerce
Most of the time you want to get the IDs of the products in the cart so that you can make some comparison with some other logic - example settings in the backend.
In such a case you can extend the answer from @Rohil_PHPBeginner and return the IDs in an array as follows :
<?php
function njengah_get_ids_of_products_in_cart(){
global $woocommerce;
$productsInCart = array();
$items = $woocommerce->cart->get_cart();
foreach($items as $item => $values) {
$_product = wc_get_product( $values['data']->get_id());
/* Display Cart Items Content */
echo "<b>".$_product->get_title().'</b> <br> Quantity: '.$values['quantity'].'<br>';
$price = get_post_meta($values['product_id'] , '_price', true);
echo " Price: ".$price."<br>";
/**Get IDs and in put them in an Array**/
$productsInCart_Ids[] = $_product->get_id();
}
/** To Display **/
print_r($productsInCart_Ids);
/**To Return for Comparision with some Other Logic**/
return $productsInCart_Ids;
}
Where is Java's Array indexOf?
Java ArrayList has an indexOf method. Java arrays have no such method.
FIFO class in Java
You can use LinkedBlockingQueue I use it in my projects. It's part of standard java and quite easy to use
How to close the current fragment by using Button like the back button?
Try this:
ft.addToBackStack(null); // ft is FragmentTransaction
So, when you press back-key, the current activity (which holds multiple fragments) will load previous fragment rather than finishing itself.
from unix timestamp to datetime
If using react:
import Moment from 'react-moment';
Moment.globalFormat = 'D MMM YYYY';
then:
<td><Moment unix>{1370001284}</Moment></td>
How to 'bulk update' with Django?
IT returns number of objects are updated in table.
update_counts = ModelClass.objects.filter(name='bar').update(name="foo")
You can refer this link to get more information on bulk update and create. Bulk update and Create
Incorrect integer value: '' for column 'id' at row 1
This is because your data sending column type is integer and your are sending a string value to it.
So, the following way worked for me. Try with this one.
$insertQuery = "INSERT INTO workorders VALUES (
null,
'$priority',
'$requestType',
'$purchaseOrder',
'$nte',
'$jobSiteNumber'
)";
Don't use 'null'. use it as null without single quotes.
How to access child's state in React?
Just before I go into detail about how you can access the state of a child component, please make sure to read Markus-ipse's answer regarding a better solution to handle this particular scenario.
If you do indeed wish to access the state of a component's children, you can assign a property called ref to each child. There are now two ways to implement references: Using React.createRef() and callback refs.
Using React.createRef()
This is currently the recommended way to use references as of React 16.3 (See the docs for more info). If you're using an earlier version then see below regarding callback references.
You'll need to create a new reference in the constructor of your parent component and then assign it to a child via the ref attribute.
class FormEditor extends React.Component {
constructor(props) {
super(props);
this.FieldEditor1 = React.createRef();
}
render() {
return <FieldEditor ref={this.FieldEditor1} />;
}
}
In order to access this kind of ref, you'll need to use:
const currentFieldEditor1 = this.FieldEditor1.current;
This will return an instance of the mounted component so you can then use currentFieldEditor1.state to access the state.
Just a quick note to say that if you use these references on a DOM node instead of a component (e.g. <div ref={this.divRef} />) then this.divRef.current will return the underlying DOM element instead of a component instance.
Callback Refs
This property takes a callback function that is passed a reference to the attached component. This callback is executed immediately after the component is mounted or unmounted.
For example:
<FieldEditor
ref={(fieldEditor1) => {this.fieldEditor1 = fieldEditor1;}
{...props}
/>
In these examples the reference is stored on the parent component. To call this component in your code, you can use:
this.fieldEditor1
and then use this.fieldEditor1.state to get the state.
One thing to note, make sure your child component has rendered before you try to access it ^_^
As above, if you use these references on a DOM node instead of a component (e.g. <div ref={(divRef) => {this.myDiv = divRef;}} />) then this.divRef will return the underlying DOM element instead of a component instance.
Further Information
If you want to read more about React's ref property, check out this page from Facebook.
Make sure you read the "Don't Overuse Refs" section that says that you shouldn't use the child's state to "make things happen".
Hope this helps ^_^
Edit: Added React.createRef() method for creating refs. Removed ES5 code.
error running apache after xampp install
I had the same problem, I solved changing the ports.
-> Clicked button Config front of Apache.
1) Select Apache (httpd.conf)
2) searched for this line: Listen 80
3) changed for this: Listen 8081
4) saved file
-> Click Config button front of Apache.
1) Select Apache (httpd-ssl.conf)
2) searched for this line: Listen 443
3) changed for this: Listen 444
4) saved file
I can run xammp from port 8081
http://localhost:8081/
You have to give port number you gave to enter the localhost
Hope this helps you to understand what is happening.
JPQL SELECT between date statement
public List<Student> findStudentByReports(Date startDate, Date endDate) {
System.out.println("call findStudentMethd******************with this pattern"
+ startDate
+ endDate
+ "*********************************************");
return em
.createQuery(
"' select attendence from Attendence attendence where attendence.admissionDate BETWEEN : startDate '' AND endDate ''"
+ "'")
.setParameter("startDate", startDate, TemporalType.DATE)
.setParameter("endDate", endDate, TemporalType.DATE)
.getResultList();
}
The program can't start because cygwin1.dll is missing... in Eclipse CDT
You can compile with either Cygwin's g++ or MinGW (via stand-alone or using Cygwin package). However, in order to run it, you need to add the Cygwin1.dll (and others) PATH to the system Windows PATH, before any cygwin style paths.
Thus add: ;C:\cygwin64\bin to the end of your Windows system PATH variable.
Also, to compile for use in CMD or PowerShell, you may need to use:
x86_64-w64-mingw32-g++.exe -static -std=c++11 prog_name.cc -o prog_name.exe
(This invokes the cross-compiler, if installed.)
How to overload functions in javascript?
There are multiple aspects to argument overloading in Javascript:
Variable arguments - You can pass different sets of arguments (in both type and quantity) and the function will behave in a way that matches the arguments passed to it.
Default arguments - You can define a default value for an argument if it is not passed.
Named arguments - Argument order becomes irrelevant and you just name which arguments you want to pass to the function.
Below is a section on each of these categories of argument handling.
Variable Arguments
Because javascript has no type checking on arguments or required qty of arguments, you can just have one implementation of myFunc() that can adapt to what arguments were passed to it by checking the type, presence or quantity of arguments.
jQuery does this all the time. You can make some of the arguments optional or you can branch in your function depending upon what arguments are passed to it.
In implementing these types of overloads, you have several different techniques you can use:
- You can check for the presence of any given argument by checking to see if the declared argument name value is
undefined. - You can check the total quantity or arguments with
arguments.length. - You can check the type of any given argument.
- For variable numbers of arguments, you can use the
argumentspseudo-array to access any given argument witharguments[i].
Here are some examples:
Let's look at jQuery's obj.data() method. It supports four different forms of usage:
obj.data("key");
obj.data("key", value);
obj.data();
obj.data(object);
Each one triggers a different behavior and, without using this dynamic form of overloading, would require four separate functions.
Here's how one can discern between all these options in English and then I'll combine them all in code:
// get the data element associated with a particular key value
obj.data("key");
If the first argument passed to .data() is a string and the second argument is undefined, then the caller must be using this form.
// set the value associated with a particular key
obj.data("key", value);
If the second argument is not undefined, then set the value of a particular key.
// get all keys/values
obj.data();
If no arguments are passed, then return all keys/values in a returned object.
// set all keys/values from the passed in object
obj.data(object);
If the type of the first argument is a plain object, then set all keys/values from that object.
Here's how you could combine all of those in one set of javascript logic:
// method declaration for .data()
data: function(key, value) {
if (arguments.length === 0) {
// .data()
// no args passed, return all keys/values in an object
} else if (typeof key === "string") {
// first arg is a string, look at type of second arg
if (typeof value !== "undefined") {
// .data("key", value)
// set the value for a particular key
} else {
// .data("key")
// retrieve a value for a key
}
} else if (typeof key === "object") {
// .data(object)
// set all key/value pairs from this object
} else {
// unsupported arguments passed
}
},
The key to this technique is to make sure that all forms of arguments you want to accept are uniquely identifiable and there is never any confusion about which form the caller is using. This generally requires ordering the arguments appropriately and making sure that there is enough uniqueness in the type and position of the arguments that you can always tell which form is being used.
For example, if you have a function that takes three string arguments:
obj.query("firstArg", "secondArg", "thirdArg");
You can easily make the third argument optional and you can easily detect that condition, but you cannot make only the second argument optional because you can't tell which of these the caller means to be passing because there is no way to identify if the second argument is meant to be the second argument or the second argument was omitted so what's in the second argument's spot is actually the third argument:
obj.query("firstArg", "secondArg");
obj.query("firstArg", "thirdArg");
Since all three arguments are the same type, you can't tell the difference between different arguments so you don't know what the caller intended. With this calling style, only the third argument can be optional. If you wanted to omit the second argument, it would have to be passed as null (or some other detectable value) instead and your code would detect that:
obj.query("firstArg", null, "thirdArg");
Here's a jQuery example of optional arguments. both arguments are optional and take on default values if not passed:
clone: function( dataAndEvents, deepDataAndEvents ) {
dataAndEvents = dataAndEvents == null ? false : dataAndEvents;
deepDataAndEvents = deepDataAndEvents == null ? dataAndEvents : deepDataAndEvents;
return this.map( function () {
return jQuery.clone( this, dataAndEvents, deepDataAndEvents );
});
},
Here's a jQuery example where the argument can be missing or any one of three different types which gives you four different overloads:
html: function( value ) {
if ( value === undefined ) {
return this[0] && this[0].nodeType === 1 ?
this[0].innerHTML.replace(rinlinejQuery, "") :
null;
// See if we can take a shortcut and just use innerHTML
} else if ( typeof value === "string" && !rnoInnerhtml.test( value ) &&
(jQuery.support.leadingWhitespace || !rleadingWhitespace.test( value )) &&
!wrapMap[ (rtagName.exec( value ) || ["", ""])[1].toLowerCase() ] ) {
value = value.replace(rxhtmlTag, "<$1></$2>");
try {
for ( var i = 0, l = this.length; i < l; i++ ) {
// Remove element nodes and prevent memory leaks
if ( this[i].nodeType === 1 ) {
jQuery.cleanData( this[i].getElementsByTagName("*") );
this[i].innerHTML = value;
}
}
// If using innerHTML throws an exception, use the fallback method
} catch(e) {
this.empty().append( value );
}
} else if ( jQuery.isFunction( value ) ) {
this.each(function(i){
var self = jQuery( this );
self.html( value.call(this, i, self.html()) );
});
} else {
this.empty().append( value );
}
return this;
},
Named Arguments
Other languages (like Python) allow one to pass named arguments as a means of passing only some arguments and making the arguments independent of the order they are passed in. Javascript does not directly support the feature of named arguments. A design pattern that is commonly used in its place is to pass a map of properties/values. This can be done by passing an object with properties and values or in ES6 and above, you could actually pass a Map object itself.
Here's a simple ES5 example:
jQuery's $.ajax() accepts a form of usage where you just pass it a single parameter which is a regular Javascript object with properties and values. Which properties you pass it determine which arguments/options are being passed to the ajax call. Some may be required, many are optional. Since they are properties on an object, there is no specific order. In fact, there are more than 30 different properties that can be passed on that object, only one (the url) is required.
Here's an example:
$.ajax({url: "http://www.example.com/somepath", data: myArgs, dataType: "json"}).then(function(result) {
// process result here
});
Inside of the $.ajax() implementation, it can then just interrogate which properties were passed on the incoming object and use those as named arguments. This can be done either with for (prop in obj) or by getting all the properties into an array with Object.keys(obj) and then iterating that array.
This technique is used very commonly in Javascript when there are large numbers of arguments and/or many arguments are optional. Note: this puts an onus on the implementating function to make sure that a minimal valid set of arguments is present and to give the caller some debug feedback what is missing if insufficient arguments are passed (probably by throwing an exception with a helpful error message).
In an ES6 environment, it is possible to use destructuring to create default properties/values for the above passed object. This is discussed in more detail in this reference article.
Here's one example from that article:
function selectEntries({ start=0, end=-1, step=1 } = {}) {
···
};
This creates default properties and values for the start, end and step properties on an object passed to the selectEntries() function.
Default values for function arguments
In ES6, Javascript adds built-in language support for default values for arguments.
For example:
function multiply(a, b = 1) {
return a*b;
}
multiply(5); // 5
Further description of the ways this can be used here on MDN.
Difference between add(), replace(), and addToBackStack()
Although it is an old question already answered, maybe those next examples can complement the accepted answer and they can be useful for some new programmers in Android as I am.
Option 1 - "addToBackStack()" is never used
Case 1A - adding, removing, and clicking Back button
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
add Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment B is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy()
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() App is closed, nothing is visible
Case 1B - adding, replacing, and clicking Back button
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(replace Fragment C)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy()
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() App is closed, nothing is visible
Option 2 - "addToBackStack()" is always used
Case 2A - adding, removing, and clicking Back button
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
add Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() Fragment B is visible
(Back button clicked)
Fragment C : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment B is visible
(Back button clicked)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment A is visible
(Back button clicked)
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
Case 2B - adding, replacing, removing, and clicking Back button
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(replace Fragment C)
Fragment B : onPause() - onStop() - onDestroyView()
Fragment A : onPause() - onStop() - onDestroyView()
Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() Activity is visible
(Back button clicked)
Fragment C : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onCreateView() - onActivityCreated() - onStart() - onResume()
Fragment B : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(Back button clicked)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment A is visible
(Back button clicked)
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
Option 3 - "addToBackStack()" is not used always (in the below examples, w/o indicates that it is not used)
Case 3A - adding, removing, and clicking Back button
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B w/o: onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
add Fragment C w/o: onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment B is visible
(Back button clicked)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
Case 3B - adding, replacing, removing, and clicking Back button
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B w/o: onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(replace Fragment C)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onPause() - onStop() - onDestroyView()
Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() Activity is visible
(Back button clicked)
Fragment C : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
(Back button clicked)
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
passing 2 $index values within nested ng-repeat
Each ng-repeat creates a child scope with the passed data, and also adds an additional $index variable in that scope.
So what you need to do is reach up to the parent scope, and use that $index.
See http://plnkr.co/edit/FvVhirpoOF8TYnIVygE6?p=preview
<li class="tutorial_title {{tutorial.active}}" ng-click="loadFromMenu($parent.$index)" ng-repeat="tutorial in section.tutorials">
{{tutorial.name}}
</li>
Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?
psql's inline help:
\h ALTER TABLE
Also documented in the postgres docs (an excellent resource, plus easy to read, too).
ALTER TABLE tablename ADD CONSTRAINT constraintname UNIQUE (columns);
How to find common elements from multiple vectors?
There might be a cleverer way to go about this, but
intersect(intersect(a,b),c)
will do the job.
EDIT: More cleverly, and more conveniently if you have a lot of arguments:
Reduce(intersect, list(a,b,c))
What is the use of a private static variable in Java?
Of course it can be accessed as ClassName.var_name, but only from inside the class in which it is defined - that's because it is defined as private.
public static or private static variables are often used for constants. For example, many people don't like to "hard-code" constants in their code; they like to make a public static or private static variable with a meaningful name and use that in their code, which should make the code more readable. (You should also make such constants final).
For example:
public class Example {
private final static String JDBC_URL = "jdbc:mysql://localhost/shopdb";
private final static String JDBC_USERNAME = "username";
private final static String JDBC_PASSWORD = "password";
public static void main(String[] args) {
Connection conn = DriverManager.getConnection(JDBC_URL,
JDBC_USERNAME, JDBC_PASSWORD);
// ...
}
}
Whether you make it public or private depends on whether you want the variables to be visible outside the class or not.
How to sort in-place using the merge sort algorithm?
The critical step is getting the merge itself to be in-place. It's not as difficult as those sources make out, but you lose something when you try.
Looking at one step of the merge:
[...list-sorted...|x...list-A...|y...list-B...]
We know that the sorted sequence is less than everything else, that x is less than everything else in A, and that y is less than everything else in B. In the case where x is less than or equal to y, you just move your pointer to the start of A on one. In the case where y is less than x, you've got to shuffle y past the whole of A to sorted. That last step is what makes this expensive (except in degenerate cases).
It's generally cheaper (especially when the arrays only actually contain single words per element, e.g., a pointer to a string or structure) to trade off some space for time and have a separate temporary array that you sort back and forth between.
MySQL high CPU usage
As this is the top post if you google for MySQL high CPU usage or load, I'll add an additional answer:
On the 1st of July 2012, a leap second was added to the current UTC-time to compensate for the slowing rotation of the earth due to the tides. When running ntp (or ntpd) this second was added to your computer's/server's clock. MySQLd does not seem to like this extra second on some OS'es, and yields a high CPU load. The quick fix is (as root):
$ /etc/init.d/ntpd stop
$ date -s "`date`"
$ /etc/init.d/ntpd start
Cast Object to Generic Type for returning
If you do not want to depend on throwing exception (which you probably should not) you can try this:
public static <T> T cast(Object o, Class<T> clazz) {
return clazz.isInstance(o) ? clazz.cast(o) : null;
}
Arduino Sketch upload issue - avrdude: stk500_recv(): programmer is not responding
I had to select the correct board. Go to menu Tools → Boards → Arduino Nano for example.
Good tool for testing socket connections?
Hercules is fantastic. It's a fully functioning tcp/udp client/server, amazing for debugging sockets. More details on the web site.
How do I change the background of a Frame in Tkinter?
The root of the problem is that you are unknowingly using the Frame class from the ttk package rather than from the tkinter package. The one from ttk does not support the background option.
This is the main reason why you shouldn't do global imports -- you can overwrite the definition of classes and commands.
I recommend doing imports like this:
import tkinter as tk
import ttk
Then you prefix the widgets with either tk or ttk :
f1 = tk.Frame(..., bg=..., fg=...)
f2 = ttk.Frame(..., style=...)
It then becomes instantly obvious which widget you are using, at the expense of just a tiny bit more typing. If you had done this, this error in your code would never have happened.
Difference between jQuery parent(), parents() and closest() functions
from http://api.jquery.com/closest/
The .parents() and .closest() methods are similar in that they both traverse up the DOM tree. The differences between the two, though subtle, are significant:
.closest()
- Begins with the current element
- Travels up the DOM tree until it finds a match for the supplied selector
- The returned jQuery object contains zero or one element
.parents()
- Begins with the parent element
- Travels up the DOM tree to the document's root element, adding each ancestor element to a temporary collection; it then filters that collection based on a selector if one is supplied
- The returned jQuery object contains zero, one, or multiple elements
.parent()
- Given a jQuery object that represents a set of DOM elements, the .parent() method allows us to search through the parents of these elements in the DOM tree and construct a new jQuery object from the matching elements.
Note: The .parents() and .parent() methods are similar, except that the latter only travels a single level up the DOM tree. Also, $("html").parent() method returns a set containing document whereas $("html").parents() returns an empty set.
Here are related threads:
How to change the display name for LabelFor in razor in mvc3?
@Html.LabelFor(model => model.SomekingStatus, "foo bar")
Changing the resolution of a VNC session in linux
I'm running TigerVNC on my Linux server, which has basic randr support. I just start vncserver without any -randr or multiple -geometry options.
When I run xrandr in a terminal, it displays all the available screen resolutions:
bash> xrandr
SZ: Pixels Physical Refresh
0 1920 x 1200 ( 271mm x 203mm ) 60
1 1920 x 1080 ( 271mm x 203mm ) 60
2 1600 x 1200 ( 271mm x 203mm ) 60
3 1680 x 1050 ( 271mm x 203mm ) 60
4 1400 x 1050 ( 271mm x 203mm ) 60
5 1360 x 768 ( 271mm x 203mm ) 60
6 1280 x 1024 ( 271mm x 203mm ) 60
7 1280 x 960 ( 271mm x 203mm ) 60
8 1280 x 800 ( 271mm x 203mm ) 60
9 1280 x 720 ( 271mm x 203mm ) 60
*10 1024 x 768 ( 271mm x 203mm ) *60
11 800 x 600 ( 271mm x 203mm ) 60
12 640 x 480 ( 271mm x 203mm ) 60
Current rotation - normal
Current reflection - none
Rotations possible - normal
Reflections possible - none
I can then easily switch to another resolution (f.e. switch to 1360x768):
bash> xrandr -s 5
I'm using TightVnc viewer as the client and it automatically adapts to the new resolution.
Setting mime type for excel document
I was setting MIME type from .NET code as below -
File(generatedFileName, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
My application generates excel using OpenXML SDK. This MIME type worked -
vnd.openxmlformats-officedocument.spreadsheetml.sheet
ASP.NET Temporary files cleanup
Just an update on more current OS's (Vista, Win7, etc.) - the temp file path has changed may be different based on several variables. The items below are not definitive, however, they are a few I have encountered:
"temp" environment variable setting - then it would be:
%temp%\Temporary ASP.NET Files
Permissions and what application/process (VS, IIS, IIS Express) is running the .Net compiler. Accessing the C:\WINDOWS\Microsoft.NET\Framework folders requires elevated permissions and if you are not developing under an account with sufficient permissions then this folder might be used:
c:\Users\[youruserid]\AppData\Local\Temp\Temporary ASP.NET Files
There are also cases where the temp folder can be set via config for a machine or site specific using this:
<compilation tempDirectory="d:\MyTempPlace" />
I even have a funky setup at work where we don't run Admin by default, plus the IT guys have login scripts that set %temp% and I get temp files in 3 different locations depending on what is compiling things! And I'm still not certain about how these paths get picked....sigh.
Still, dthrasher is correct, you can just delete these and VS and IIS will just recompile them as needed.
Firebug-like debugger for Google Chrome
Forget everything you all needs this browser independent inspector , dom updater
https://goggles.webmaker.org/en-US
just bookmark and go to any webpage and click that bookmark..
this is actually Mozilla project Goggles , amazing amazing amazing...
How to remove space from string?
A funny way to remove all spaces from a variable is to use printf:
$ myvar='a cool variable with lots of spaces in it'
$ printf -v myvar '%s' $myvar
$ echo "$myvar"
acoolvariablewithlotsofspacesinit
It turns out it's slightly more efficient than myvar="${myvar// /}", but not safe regarding globs (*) that can appear in the string. So don't use it in production code.
If you really really want to use this method and are really worried about the globbing thing (and you really should), you can use set -f (which disables globbing altogether):
$ ls
file1 file2
$ myvar=' a cool variable with spaces and oh! no! there is a glob * in it'
$ echo "$myvar"
a cool variable with spaces and oh! no! there is a glob * in it
$ printf '%s' $myvar ; echo
acoolvariablewithspacesandoh!no!thereisaglobfile1file2init
$ # See the trouble? Let's fix it with set -f:
$ set -f
$ printf '%s' $myvar ; echo
acoolvariablewithspacesandoh!no!thereisaglob*init
$ # Since we like globbing, we unset the f option:
$ set +f
I posted this answer just because it's funny, not to use it in practice.
Rails 4 - passing variable to partial
From the Rails api on PartialRender:
Rendering the default case
If you're not going to be using any of the options like collections or layouts, you can also use the short-hand defaults of render to render partials.
Examples:
# Instead of <%= render partial: "account" %>
<%= render "account" %>
# Instead of <%= render partial: "account", locals: { account: @buyer } %>
<%= render "account", account: @buyer %>
# @account.to_partial_path returns 'accounts/account', so it can be used to replace:
# <%= render partial: "accounts/account", locals: { account: @account} %>
<%= render @account %>
# @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
# that's why we can replace:
# <%= render partial: "posts/post", collection: @posts %>
<%= render @posts %>
So, you can use pass a local variable size to render as follows:
<%= render @users, size: 50 %>
and then use it in the _user.html.erb partial:
<li>
<%= gravatar_for user, size: size %>
<%= link_to user.name, user %>
</li>
Note that size: size is equivalent to :size => size.
Is there a way since (iOS 7's release) to get the UDID without using iTunes on a PC/Mac?
Plug it in, and run this from the command line:
system_profiler SPUSBDataType
Look for:
Serial Number: xxxx
SQL Add foreign key to existing column
ALTER TABLE Faculty
WITH CHECK ADD CONSTRAINT FKFacultyBook
FOREIGN KEY FacId
REFERENCES Book Book_Id
ALTER TABLE Faculty
WITH CHECK ADD CONSTRAINT FKFacultyStudent
FOREIGN KEY FacId
REFERENCES Student StuId
How can the error 'Client found response content type of 'text/html'.. be interpreted
I had this happen as a result of a configuration error in web.config. Checking the connection string etc might be the answer for the time out.
Create numpy matrix filled with NaNs
You can always use multiplication if you don't immediately recall the .empty or .full methods:
>>> np.nan * np.ones(shape=(3,2))
array([[ nan, nan],
[ nan, nan],
[ nan, nan]])
Of course it works with any other numerical value as well:
>>> 42 * np.ones(shape=(3,2))
array([[ 42, 42],
[ 42, 42],
[ 42, 42]])
But the @u0b34a0f6ae's accepted answer is 3x faster (CPU cycles, not brain cycles to remember numpy syntax ;):
$ python -mtimeit "import numpy as np; X = np.empty((100,100));" "X[:] = np.nan;"
100000 loops, best of 3: 8.9 usec per loop
(predict)laneh@predict:~/src/predict/predict/webapp$ master
$ python -mtimeit "import numpy as np; X = np.ones((100,100));" "X *= np.nan;"
10000 loops, best of 3: 24.9 usec per loop
[Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
I got this with data driven tests using:
Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb)
The problem is the above driver only is 32 bit. I had switched visual studio testsettings file to 64 bit to test a 64-bit-only application.
Switching back to 32 bit in the testsettings file fixed the issue.
ECMAScript 6 class destructor
Is there such a thing as destructors for ECMAScript 6?
No. EcmaScript 6 does not specify any garbage collection semantics at all[1], so there is nothing like a "destruction" either.
If I register some of my object's methods as event listeners in the constructor, I want to remove them when my object is deleted
A destructor wouldn't even help you here. It's the event listeners themselves that still reference your object, so it would not be able to get garbage-collected before they are unregistered.
What you are actually looking for is a method of registering listeners without marking them as live root objects. (Ask your local eventsource manufacturer for such a feature).
1): Well, there is a beginning with the specification of WeakMap and WeakSet objects. However, true weak references are still in the pipeline [1][2].
C++ Array of pointers: delete or delete []?
To simplify the answare let's look on the following code:
#include "stdafx.h"
#include <iostream>
using namespace std;
class A
{
private:
int m_id;
static int count;
public:
A() {count++; m_id = count;}
A(int id) { m_id = id; }
~A() {cout<< "Destructor A " <<m_id<<endl; }
};
int A::count = 0;
void f1()
{
A* arr = new A[10];
//delete operate only one constructor, and crash!
delete arr;
//delete[] arr;
}
int main()
{
f1();
system("PAUSE");
return 0;
}
The output is: Destructor A 1 and then it's crashing (Expression: _BLOCK_TYPE_IS_VALID(phead- nBlockUse)).
We need to use: delete[] arr; becuse it's delete the whole array and not just one cell!
try to use delete[] arr; the output is: Destructor A 10 Destructor A 9 Destructor A 8 Destructor A 7 Destructor A 6 Destructor A 5 Destructor A 4 Destructor A 3 Destructor A 2 Destructor A 1
The same principle is for an array of pointers:
void f2()
{
A** arr = new A*[10];
for(int i = 0; i < 10; i++)
{
arr[i] = new A(i);
}
for(int i = 0; i < 10; i++)
{
delete arr[i];//delete the A object allocations.
}
delete[] arr;//delete the array of pointers
}
if we'll use delete arr instead of delete[] arr. it will not delete the whole pointers in the array => memory leak of pointer objects!
implementing merge sort in C++
I've rearranged the selected answer, used pointers for arrays and user input for number count is not pre-defined.
#include <iostream>
using namespace std;
void merge(int*, int*, int, int, int);
void mergesort(int *a, int*b, int start, int end) {
int halfpoint;
if (start < end) {
halfpoint = (start + end) / 2;
mergesort(a, b, start, halfpoint);
mergesort(a, b, halfpoint + 1, end);
merge(a, b, start, halfpoint, end);
}
}
void merge(int *a, int *b, int start, int halfpoint, int end) {
int h, i, j, k;
h = start;
i = start;
j = halfpoint + 1;
while ((h <= halfpoint) && (j <= end)) {
if (a[h] <= a[j]) {
b[i] = a[h];
h++;
} else {
b[i] = a[j];
j++;
}
i++;
}
if (h > halfpoint) {
for (k = j; k <= end; k++) {
b[i] = a[k];
i++;
}
} else {
for (k = h; k <= halfpoint; k++) {
b[i] = a[k];
i++;
}
}
// Write the final sorted array to our original one
for (k = start; k <= end; k++) {
a[k] = b[k];
}
}
int main(int argc, char** argv) {
int num;
cout << "How many numbers do you want to sort: ";
cin >> num;
int a[num];
int b[num];
for (int i = 0; i < num; i++) {
cout << (i + 1) << ": ";
cin >> a[i];
}
// Start merge sort
mergesort(a, b, 0, num - 1);
// Print the sorted array
cout << endl;
for (int i = 0; i < num; i++) {
cout << a[i] << " ";
}
cout << endl;
return 0;
}
Modular multiplicative inverse function in Python
I try different solutions from this thread and in the end I use this one:
def egcd(a, b):
lastremainder, remainder = abs(a), abs(b)
x, lastx, y, lasty = 0, 1, 1, 0
while remainder:
lastremainder, (quotient, remainder) = remainder, divmod(lastremainder, remainder)
x, lastx = lastx - quotient*x, x
y, lasty = lasty - quotient*y, y
return lastremainder, lastx * (-1 if a < 0 else 1), lasty * (-1 if b < 0 else 1)
def modinv(a, m):
g, x, y = self.egcd(a, m)
if g != 1:
raise ValueError('modinv for {} does not exist'.format(a))
return x % m
Flexbox and Internet Explorer 11 (display:flex in <html>?)
You just need flex:1; It will fix issue for the IE11. I second Odisseas. Additionally assign 100% height to html,body elements.
CSS changes:
html, body{
height:100%;
}
body {
border: red 1px solid;
min-height: 100vh;
display: -ms-flexbox;
display: -webkit-flex;
display: flex;
-ms-flex-direction: column;
-webkit-flex-direction: column;
flex-direction: column;
}
header {
background: #23bcfc;
}
main {
background: #87ccfc;
-ms-flex: 1;
-webkit-flex: 1;
flex: 1;
}
footer {
background: #dd55dd;
}
working url: http://jsfiddle.net/3tpuryso/13/
A connection was successfully established with the server, but then an error occurred during the pre-login handshake
In my case it was:
Persist Security Info=True;
in my connection string that needed to be removed. Once I did that I no longer had issues.
Jquery to get SelectedText from dropdown
Please use this
var listbox = document.getElementById("yourdropdownid");
var selIndex = listbox.selectedIndex;
var selValue = listbox.options[selIndex].value;
var selText = listbox.options[selIndex].text;
Then Please alert "selValue" and "selText". You get your selected dropdown value and text
How to find all combinations of coins when given some dollar value
/*
* make a list of all distinct sets of coins of from the set of coins to
* sum up to the given target amount.
* Here the input set of coins is assumed yo be {1, 2, 4}, this set MUST
* have the coins sorted in ascending order.
* Outline of the algorithm:
*
* Keep track of what the current coin is, say ccn; current number of coins
* in the partial solution, say k; current sum, say sum, obtained by adding
* ccn; sum sofar, say accsum:
* 1) Use ccn as long as it can be added without exceeding the target
* a) if current sum equals target, add cc to solution coin set, increase
* coin coin in the solution by 1, and print it and return
* b) if current sum exceeds target, ccn can't be in the solution, so
* return
* c) if neither of the above, add current coin to partial solution,
* increase k by 1 (number of coins in partial solution), and recuse
* 2) When current denomination can no longer be used, start using the
* next higher denomination coins, just like in (1)
* 3) When all denominations have been used, we are done
*/
#include <iostream>
#include <cstdlib>
using namespace std;
// int num_calls = 0;
// int num_ways = 0;
void print(const int coins[], int n);
void combine_coins(
const int denoms[], // coins sorted in ascending order
int n, // number of denominations
int target, // target sum
int accsum, // accumulated sum
int coins[], // solution set, MUST equal
// target / lowest denom coin
int k // number of coins in coins[]
)
{
int ccn; // current coin
int sum; // current sum
// ++num_calls;
for (int i = 0; i < n; ++i) {
/*
* skip coins of lesser denomination: This is to be efficient
* and also avoid generating duplicate sequences. What we need
* is combinations and without this check we will generate
* permutations.
*/
if (k > 0 && denoms[i] < coins[k - 1])
continue; // skip coins of lesser denomination
ccn = denoms[i];
if ((sum = accsum + ccn) > target)
return; // no point trying higher denominations now
if (sum == target) {
// found yet another solution
coins[k] = ccn;
print(coins, k + 1);
// ++num_ways;
return;
}
coins[k] = ccn;
combine_coins(denoms, n, target, sum, coins, k + 1);
}
}
void print(const int coins[], int n)
{
int s = 0;
for (int i = 0; i < n; ++i) {
cout << coins[i] << " ";
s += coins[i];
}
cout << "\t = \t" << s << "\n";
}
int main(int argc, const char *argv[])
{
int denoms[] = {1, 2, 4};
int dsize = sizeof(denoms) / sizeof(denoms[0]);
int target;
if (argv[1])
target = atoi(argv[1]);
else
target = 8;
int *coins = new int[target];
combine_coins(denoms, dsize, target, 0, coins, 0);
// cout << "num calls = " << num_calls << ", num ways = " << num_ways << "\n";
return 0;
}
How to inject JPA EntityManager using spring
Yes, although it's full of gotchas, since JPA is a bit peculiar. It's very much worth reading the documentation on injecting JPA EntityManager and EntityManagerFactory, without explicit Spring dependencies in your code:
http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/orm.html#orm-jpa
This allows you to either inject the EntityManagerFactory, or else inject a thread-safe, transactional proxy of an EntityManager directly. The latter makes for simpler code, but means more Spring plumbing is required.
Excel add one hour
This may help you as well. This is a conditional statement that will fill the cell with a default date if it is empty but will subtract one hour if it is a valid date/time and put it into the cell.
=IF((Sheet1!C4)="",DATE(1999,1,1),Sheet1!C4-TIME(1,0,0))
You can also substitute TIME with DATE to add or subtract a date or time.
Get last dirname/filename in a file path argument in Bash
basename does remove the directory prefix of a path:
$ basename /usr/local/svn/repos/example
example
$ echo "/server/root/$(basename /usr/local/svn/repos/example)"
/server/root/example
Remove non-numeric characters (except periods and commas) from a string
Simplest way to truly remove all non-numeric characters:
echo preg_replace('/\D/', '', $string);
\D represents "any character that is not a decimal digit"
Making LaTeX tables smaller?
You could add \singlespacing near the beginning of your table. See the setspace instructions for more options.
Correct way of looping through C++ arrays
You can do it as follow:
#include < iostream >
using namespace std;
int main () {
string texts[] = {"Apple", "Banana", "Orange"};
for( unsigned int a = 0; a < sizeof(texts) / 32; a++ ) { // 32 is the size of string data type
cout << "value of a: " << texts[a] << endl;
}
return 0;
}
bootstrap 4 row height
Use the sizing utility classes...
h-50= height 50%h-100= height 100%
http://www.codeply.com/go/Y3nG0io2uE
<div class="container">
<div class="row">
<div class="col-md-8 col-lg-6 B">
<div class="card card-inverse card-primary">
<img src="http://lorempicsum.com/rio/800/500/4" class="img-fluid" alt="Responsive image">
</div>
</div>
<div class="col-md-4 col-lg-3 G">
<div class="row h-100">
<div class="col-md-6 col-lg-6 B h-50 pb-3">
<div class="card card-inverse card-success h-100">
</div>
</div>
<div class="col-md-6 col-lg-6 B h-50 pb-3">
<div class="card card-inverse bg-success h-100">
</div>
</div>
<div class="col-md-12 h-50">
<div class="card card-inverse bg-danger h-100">
</div>
</div>
</div>
</div>
</div>
</div>
Or, for an unknown number of child columns, use flexbox and the cols will fill height. See the d-flex flex-column on the row, and h-100 on the child cols.
<div class="container">
<div class="row">
<div class="col-md-8 col-lg-6 B">
<div class="card card-inverse card-primary">
<img src="http://lorempicsum.com/rio/800/500/4" class="img-fluid" alt="Responsive image">
</div>
</div>
<div class="col-md-4 col-lg-3 G ">
<div class="row d-flex flex-column h-100">
<div class="col-md-6 col-lg-6 B h-100">
<div class="card bg-success h-100">
</div>
</div>
<div class="col-md-6 col-lg-6 B h-100">
<div class="card bg-success h-100">
</div>
</div>
<div class="col-md-12 h-100">
<div class="card bg-danger h-100">
</div>
</div>
</div>
</div>
</div>
</div>
Deleting objects from an ArrayList in Java
I have found an alternative faster solution:
int j = 0;
for (Iterator i = list.listIterator(); i.hasNext(); ) {
j++;
if (campo.getNome().equals(key)) {
i.remove();
i = list.listIterator(j);
}
}
Do we need type="text/css" for <link> in HTML5
The HTML5 spec says that the type attribute is purely advisory and explains in detail how browsers should act if it's omitted (too much to quote here). It doesn't explicitly say that an omitted type attribute is either valid or invalid, but you can safely omit it knowing that browsers will still react as you expect.
How can you undo the last git add?
You cannot undo the latest git add, but you can undo all adds since the last commit. git reset without a commit argument resets the index (unstages staged changes):
git reset
How do I execute .js files locally in my browser?
If you're using Google Chrome you can use the Chrome Dev Editor: https://github.com/dart-lang/chromedeveditor
Pandas DataFrame Groupby two columns and get counts
Inserting data into a pandas dataframe and providing column name.
import pandas as pd
df = pd.DataFrame([['A','C','A','B','C','A','B','B','A','A'], ['ONE','TWO','ONE','ONE','ONE','TWO','ONE','TWO','ONE','THREE']]).T
df.columns = [['Alphabet','Words']]
print(df) #printing dataframe.
This is our printed data:
For making a group of dataframe in pandas and counter,
You need to provide one more column which counts the grouping, let's call that column as, "COUNTER" in dataframe.
Like this:
df['COUNTER'] =1 #initially, set that counter to 1.
group_data = df.groupby(['Alphabet','Words'])['COUNTER'].sum() #sum function
print(group_data)
OUTPUT:
Spring Boot java.lang.NoClassDefFoundError: javax/servlet/Filter
That looks like you tried to add the libraries servlet.jar or servlet-api.jar into your project /lib/ folder, but Tomcat already should provide you with those libraries. Remove them from your project and classpath. Search for that anywhere in your project or classpath and remove it.
Key existence check in HashMap
You won't gain anything by checking that the key exists. This is the code of HashMap:
@Override
public boolean containsKey(Object key) {
Entry<K, V> m = getEntry(key);
return m != null;
}
@Override
public V get(Object key) {
Entry<K, V> m = getEntry(key);
if (m != null) {
return m.value;
}
return null;
}
Just check if the return value for get() is different from null.
This is the HashMap source code.
Resources :
HashMap source codeBad one- HashMap source code Good one
How to update and order by using ms sql
WITH q AS
(
SELECT TOP 10 *
FROM messages
WHERE status = 0
ORDER BY
priority DESC
)
UPDATE q
SET status = 10
embedding image in html email
You need 3 boundaries for inline images to be fully compliant.
Everything goes inside the
multipart/mixed.Then use the
multipart/relatedto contain yourmultipart/alternativeand your image attachment headers.Lastly, include your downloadable attachments inside the last boundary of
multipart/mixed.
SCRIPT7002: XMLHttpRequest: Network Error 0x2ef3, Could not complete the operation due to error 00002ef3
I have stumbled across this questions and answers after receiving the aforementioned error in IE11 when trying to upload files using XMLHttpRequest:
var reqObj = new XMLHttpRequest();
//event Handler
reqObj.upload.addEventListener("progress", uploadProgress, false);
reqObj.addEventListener("load", uploadComplete, false);
reqObj.addEventListener("error", uploadFailed, false);
reqObj.addEventListener("abort", uploadCanceled, false);
//open the object and set method of call (post), url to call, isAsynchronous(true)
reqObj.open("POST", $rootUrlService.rootUrl + "Controller/UploadFiles", true);
//set Content-Type at request header.for file upload it's value must be multipart/form-data
reqObj.setRequestHeader("Content-Type", "multipart/form-data");
//Set header properties : file name and project milestone id
reqObj.setRequestHeader('X-File-Name', name);
// send the file
// this is the line where the error occurs
reqObj.send(fileToUpload);
Removing the line reqObj.setRequestHeader("Content-Type", "multipart/form-data"); fixed the problem.
Note: this error is shown very differently in other browsers. I.e. Chrome shows something similar to a connection reset which is similar to what Fiddler reports (an empty response due to sudden connection close).
Also, this error appeared only when upload was done from a machine different from WebServer (no problems on localhost).
Rock, Paper, Scissors Game Java
Before we try to solve the invalid character problem, the lack of curly braces around the if and else if statements is wreaking havoc on your program's logic. Change it to this:
if (personPlay.equals(computerPlay)) {
System.out.println("It's a tie!");
}
else if (personPlay.equals("R")) {
if (computerPlay.equals("S"))
System.out.println("Rock crushes scissors. You win!!");
else if (computerPlay.equals("P"))
System.out.println("Paper eats rock. You lose!!");
}
else if (personPlay.equals("P")) {
if (computerPlay.equals("S"))
System.out.println("Scissor cuts paper. You lose!!");
else if (computerPlay.equals("R"))
System.out.println("Paper eats rock. You win!!");
}
else if (personPlay.equals("S")) {
if (computerPlay.equals("P"))
System.out.println("Scissor cuts paper. You win!!");
else if (computerPlay.equals("R"))
System.out.println("Rock breaks scissors. You lose!!");
}
else
System.out.println("Invalid user input.");
Much clearer! It's now actually a piece of cake to catch the bad characters. You need to move the else statement to somewhere that will catch the errors before you attempt to process anything else. So change everything to:
if( /* insert your check for bad characters here */ ) {
System.out.println("Invalid user input.");
}
else if (personPlay.equals(computerPlay)) {
System.out.println("It's a tie!");
}
else if (personPlay.equals("R")) {
if (computerPlay.equals("S"))
System.out.println("Rock crushes scissors. You win!!");
else if (computerPlay.equals("P"))
System.out.println("Paper eats rock. You lose!!");
}
else if (personPlay.equals("P")) {
if (computerPlay.equals("S"))
System.out.println("Scissor cuts paper. You lose!!");
else if (computerPlay.equals("R"))
System.out.println("Paper eats rock. You win!!");
}
else if (personPlay.equals("S")) {
if (computerPlay.equals("P"))
System.out.println("Scissor cuts paper. You win!!");
else if (computerPlay.equals("R"))
System.out.println("Rock breaks scissors. You lose!!");
}
How do I initialize the base (super) class?
As of python 3.5.2, you can use:
class C(B):
def method(self, arg):
super().method(arg) # This does the same thing as:
# super(C, self).method(arg)
Creating a search form in PHP to search a database?
You're getting errors 'table liam does not exist' because the table's name is Liam which is not the same as liam. MySQL table names are case sensitive.
Angular - POST uploaded file
Look at my code, but be aware. I use async/await, because latest Chrome beta can read any es6 code, which gets by TypeScript with compilation. So, you must replace asyns/await by .then().
Input change handler:
/**
* @param fileInput
*/
public psdTemplateSelectionHandler (fileInput: any){
let FileList: FileList = fileInput.target.files;
for (let i = 0, length = FileList.length; i < length; i++) {
this.psdTemplates.push(FileList.item(i));
}
this.progressBarVisibility = true;
}
Submit handler:
public async psdTemplateUploadHandler (): Promise<any> {
let result: any;
if (!this.psdTemplates.length) {
return;
}
this.isSubmitted = true;
this.fileUploadService.getObserver()
.subscribe(progress => {
this.uploadProgress = progress;
});
try {
result = await this.fileUploadService.upload(this.uploadRoute, this.psdTemplates);
} catch (error) {
document.write(error)
}
if (!result['images']) {
return;
}
this.saveUploadedTemplatesData(result['images']);
this.redirectService.redirect(this.redirectRoute);
}
FileUploadService. That service also stored uploading progress in progress$ property, and in other places, you can subscribe on it and get new value every 500ms.
import { Component } from 'angular2/core';
import { Injectable } from 'angular2/core';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/share';
@Injectable()
export class FileUploadService {
/**
* @param Observable<number>
*/
private progress$: Observable<number>;
/**
* @type {number}
*/
private progress: number = 0;
private progressObserver: any;
constructor () {
this.progress$ = new Observable(observer => {
this.progressObserver = observer
});
}
/**
* @returns {Observable<number>}
*/
public getObserver (): Observable<number> {
return this.progress$;
}
/**
* Upload files through XMLHttpRequest
*
* @param url
* @param files
* @returns {Promise<T>}
*/
public upload (url: string, files: File[]): Promise<any> {
return new Promise((resolve, reject) => {
let formData: FormData = new FormData(),
xhr: XMLHttpRequest = new XMLHttpRequest();
for (let i = 0; i < files.length; i++) {
formData.append("uploads[]", files[i], files[i].name);
}
xhr.onreadystatechange = () => {
if (xhr.readyState === 4) {
if (xhr.status === 200) {
resolve(JSON.parse(xhr.response));
} else {
reject(xhr.response);
}
}
};
FileUploadService.setUploadUpdateInterval(500);
xhr.upload.onprogress = (event) => {
this.progress = Math.round(event.loaded / event.total * 100);
this.progressObserver.next(this.progress);
};
xhr.open('POST', url, true);
xhr.send(formData);
});
}
/**
* Set interval for frequency with which Observable inside Promise will share data with subscribers.
*
* @param interval
*/
private static setUploadUpdateInterval (interval: number): void {
setInterval(() => {}, interval);
}
}
Set background image according to screen resolution
Put into css file:
html { background: url(images/bg.jpg) no-repeat center center fixed; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover; }
URL images/bg.jpg is your background image
keypress, ctrl+c (or some combo like that)
In my case, I was looking for a keydown ctrl key and click event. My jquery looks like this:
$('.linkAccess').click( function (event) {
if(true === event.ctrlKey) {
/* Extract the value */
var $link = $('.linkAccess');
var value = $link.val();
/* Verified if the link is not null */
if('' !== value){
window.open(value);
}
}
});
Where "linkAccess" is the class name for some specific fields where I have a link and I want to access it using my combination of key and click.
Animate change of view background color on Android
I ended up figuring out a (pretty good) solution for this problem!
You can use a TransitionDrawable to accomplish this. For example, in an XML file in the drawable folder you could write something like:
<?xml version="1.0" encoding="UTF-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
<!-- The drawables used here can be solid colors, gradients, shapes, images, etc. -->
<item android:drawable="@drawable/original_state" />
<item android:drawable="@drawable/new_state" />
</transition>
Then, in your XML for the actual View you would reference this TransitionDrawable in the android:background attribute.
At this point you can initiate the transition in your code on-command by doing:
TransitionDrawable transition = (TransitionDrawable) viewObj.getBackground();
transition.startTransition(transitionTime);
Or run the transition in reverse by calling:
transition.reverseTransition(transitionTime);
See Roman's answer for another solution using the Property Animation API, which wasn't available at the time this answer was originally posted.
How to Get True Size of MySQL Database?
You can get the size of your Mysql database by running the following command in Mysql client
SELECT sum(round(((data_length + index_length) / 1024 / 1024 / 1024), 2)) as "Size in GB"
FROM information_schema.TABLES
WHERE table_schema = "<database_name>"
How to set JAVA_HOME environment variable on Mac OS X 10.9?
It is recommended to check default terminal shell before set JAVA_HOME environment variable, via following commands:
$ echo $SHELL
/bin/bash
If your default terminal is /bin/bash (Bash), then you should use @Adrian Petrescu method.
If your default terminal is /bin/zsh (Z Shell), then you should set these environment variable in ~/.zshenv file with following contents:
export JAVA_HOME="$(/usr/libexec/java_home)"
Similarly, any other terminal type not mentioned above, you should set environment variable in its respective terminal env file.
count distinct values in spreadsheet
This works if you just want the count of unique values in e.g. the following range
=counta(unique(B4:B21))
Flushing footer to bottom of the page, twitter bootstrap
Here is an example using css3:
CSS:
html, body {
height: 100%;
margin: 0;
}
#wrap {
padding: 10px;
min-height: -webkit-calc(100% - 100px); /* Chrome */
min-height: -moz-calc(100% - 100px); /* Firefox */
min-height: calc(100% - 100px); /* native */
}
.footer {
position: relative;
clear:both;
}
HTML:
<div id="wrap">
<div class="container clear-top">
body content....
</div>
</div>
<footer class="footer">
footer content....
</footer>
jQuery / Javascript code check, if not undefined
$.fn.attr(attributeName) returns the attribute value as string, or undefined when the attribute is not present.
Since "", and undefined are both falsy (evaluates to false when coerced to boolean) values in JavaScript, in this case I would write the check as below:
if (wlocation) { ... }
Converting camel case to underscore case in ruby
Short oneliner for CamelCases when you have spaces also included (doesn't work correctly if you have a word inbetween with small starting-letter):
a = "Test String"
a.gsub(' ', '').underscore
=> "test_string"
How to build minified and uncompressed bundle with webpack?
You should export an array like this:
const path = require('path');
const webpack = require('webpack');
const libName = 'YourLibraryName';
function getConfig(env) {
const config = {
mode: env,
output: {
path: path.resolve('dist'),
library: libName,
libraryTarget: 'umd',
filename: env === 'production' ? `${libName}.min.js` : `${libName}.js`
},
target: 'web',
.... your shared options ...
};
return config;
}
module.exports = [
getConfig('development'),
getConfig('production'),
];
SQL query to find third highest salary in company
The SQL-Server implementation of this will be:
SELECT SALARY FROM EMPLOYEES OFFSET 2 ROWS FETCH NEXT 1 ROWS ONLY
Dealing with multiple Python versions and PIP?
From here: https://docs.python.org/3/installing/
Here is how to install packages for various versions that are installed at the same time linux, mac, posix:
python2 -m pip install SomePackage # default Python 2
python2.7 -m pip install SomePackage # specifically Python 2.7
python3 -m pip install SomePackage # default Python 3
python3.4 -m pip install SomePackage # specifically Python 3.4
python3.5 -m pip install SomePackage # specifically Python 3.5
python3.6 -m pip install SomePackage # specifically Python 3.6
On Windows, use the py Python launcher in combination with the -m switch:
py -2 -m pip install SomePackage # default Python 2
py -2.7 -m pip install SomePackage # specifically Python 2.7
py -3 -m pip install SomePackage # default Python 3
py -3.4 -m pip install SomePackage # specifically Python 3.4
How can I start and check my MySQL log?
For me, general_log didn't worked. But adding this to my.ini worked
[mysqld]
log-output=FILE
slow_query_log = 1
slow_query_log_file = "d:/temp/developer.log"
Only one expression can be specified in the select list when the subquery is not introduced with EXISTS
You should return only one column and one row in the where query where you assign the returned value to a variable. Example:
select * from table1 where Date in (select * from Dates) -- Wrong
select * from table1 where Date in (select Column1,Column2 from Dates) -- Wrong
select * from table1 where Date in (select Column1 from Dates) -- OK
Insert all values of a table into another table in SQL
I think this statement might do what you want.
INSERT INTO newTableName (SELECT column1, column2, column3 FROM oldTable);
Error occurred during initialization of boot layer FindException: Module not found
I just encountered the same issue after adding the bin folder to .gitignore, not sure if that caused the issue.
I solved it by going to Project/Properties/Build Path and I removed the scr folder and added it again.
Getting values from JSON using Python
Using Python to extract a value from the provided Json
Working sample:-
import json
import sys
//load the data into an element
data={"test1" : "1", "test2" : "2", "test3" : "3"}
//dumps the json object into an element
json_str = json.dumps(data)
//load the json to a string
resp = json.loads(json_str)
//print the resp
print (resp)
//extract an element in the response
print (resp['test1'])
PostgreSQL - SQL state: 42601 syntax error
Your function would work like this:
CREATE OR REPLACE FUNCTION prc_tst_bulk(sql text)
RETURNS TABLE (name text, rowcount integer) AS
$$
BEGIN
RETURN QUERY EXECUTE '
WITH v_tb_person AS (' || sql || $x$)
SELECT name, count(*)::int FROM v_tb_person WHERE nome LIKE '%a%' GROUP BY name
UNION
SELECT name, count(*)::int FROM v_tb_person WHERE gender = 1 GROUP BY name$x$;
END
$$ LANGUAGE plpgsql;
Call:
SELECT * FROM prc_tst_bulk($$SELECT a AS name, b AS nome, c AS gender FROM tbl$$)
You cannot mix plain and dynamic SQL the way you tried to do it. The whole statement is either all dynamic or all plain SQL. So I am building one dynamic statement to make this work. You may be interested in the chapter about executing dynamic commands in the manual.
The aggregate function
count()returnsbigint, but you hadrowcountdefined asinteger, so you need an explicit cast::intto make this workI use dollar quoting to avoid quoting hell.
However, is this supposed to be a honeypot for SQL injection attacks or are you seriously going to use it? For your very private and secure use, it might be ok-ish - though I wouldn't even trust myself with a function like that. If there is any possible access for untrusted users, such a function is a loaded footgun. It's impossible to make this secure.
Craig (a sworn enemy of SQL injection!) might get a light stroke, when he sees what you forged from his piece of code in the answer to your preceding question. :)
The query itself seems rather odd, btw. But that's beside the point here.
How to use the DropDownList's SelectedIndexChanged event
You should add AutoPostBack="true" to DropDownList1
<asp:DropDownList ID="ddmanu" runat="server" AutoPostBack="true"
DataSourceID="Sql_fur_model_manu"
DataTextField="manufacturer" DataValueField="manufacturer"
onselectedindexchanged="ddmanu_SelectedIndexChanged">
</asp:DropDownList>
Get List of connected USB Devices
I know I'm replying to an old question, but I just went through this same exercise and found out a bit more information, that I think will contribute a lot to the discussion and help out anyone else who finds this question and sees where the existing answers fall short.
The accepted answer is close, and can be corrected using Nedko's comment to it. A more detailed understanding of the WMI Classes involved helps complete the picture.
Win32_USBHub returns only USB Hubs. That seems obvious in hindsight but the discussion above misses it. It does not include all possible USB devices, only those which can (in theory, at least) act as a hub for additional devices. It misses some devices that are not hubs (particularly parts of composite devices).
Win32_PnPEntity does include all the USB devices, and hundreds more non-USB devices. Russel Gantman's advice to use a WHERE clause search Win32_PnPEntity for a DeviceID beginning with "USB%" to filter the list is helpful but slightly incomplete; it misses bluetooth devices, some printers/print servers, and HID-compliant mice and keyboards. I have seen "USB\%", "USBSTOR\%", "USBPRINT\%", "BTH\%", "SWD\%", and "HID\%". Win32_PnPEntity is, however, a good "master" reference to look up information once you are in possession of the PNPDeviceID from other sources.
What I found was the best way to enumerate USB devices was to query Win32_USBControllerDevice. While it doesn't give detailed information for the devices, it does completely enumerate your USB devices and gives you an Antecedent/Dependent pair of PNPDeviceIDs for every USB Device (including Hubs, non-Hub devices, and HID-compliant devices) on your system. Each Dependent returned from the query will be a USB Device. The Antecedent will be the Controller it is assigned to, one of the USB Controllers returned by querying Win32_USBController.
As a bonus, it appears that under the hood, WMI walks the Device Tree when responding to the Win32_USBControllerDevice query, so the order in which these results are returned can help identify parent/child relationships. (This is not documented and is thus only a guess; use the SetupDi API's CM_Get_Parent (or Child + Sibling) for definitive results.) As an option to the SetupDi API, it appears that for all the devices listed under Win32_USBHub they can be looked up in the registry (at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ + PNPDeviceID) and will have a parameter ParentIdPrefix which will be the prefix of the last field in the PNPDeviceID of its children, so this could also be used in a wildcard match to filter the Win32_PnPEntity query.
In my application, I did the following:
- (Optional) Queried
Win32_PnPEntityand stored the results in a key-value map (with PNPDeviceID as the key) for later retrieval. This is optional if you want to do individual queries later. - Queried
Win32_USBControllerDevicefor a definitive list of USB devices on my system (all the Dependents) and extracted the PNPDeviceIDs of these. I went further, based on order following the device tree, to assign devices to the root hub (the first device returned, rather than the controller) and built a tree based on the parentIdPrefix. The order the query returns, which matches device tree enumeration via SetupDi, is each root hub (for whom the Antecedent identifies the controller), followed by an iteration of devices under it, e.g., on my system:- Root hub of first controller
- Root hub of second controller
- First hub under root hub of second controller (has parentIdPrefix)
- First composite device under first hub under root hub of second controller (PNPDeviceID matches above hub's ParentIdPrefix; has its own ParentIdPrefix)
- HID Device part of the composite device (PNPDeviceID matches above composite device's ParentIDPrefix)
- Second device under first hub under root hub of second controller
- HID Device part of the composite device
- First composite device under first hub under root hub of second controller (PNPDeviceID matches above hub's ParentIdPrefix; has its own ParentIdPrefix)
- Second hub under root hub of second controller
- First device under second hub under root hub of second controller
- Third hub under root hub of second controller
- etc.
- First hub under root hub of second controller (has parentIdPrefix)
- Queried
Win32_USBController. This gave me the detailed information of the PNPDeviceIDs of my controllers which are at the top of the device tree (which were the Antecedents of the previous query). Using the tree derived in the previous step, recursively iterated over its children (the root hubs) and their children (the other hubs) and their children (non-hub devices and composite devices) and their children, etc.- Retrieved details for each device in my tree by referencing the map stored in the first step. (Optionally, one could skip the first step, and query
Win32_PnPEntityindividually using the PNPDeviceId to get the information at this step; probably a cpu vs. memory tradeoff determining which order is better.)
- Retrieved details for each device in my tree by referencing the map stored in the first step. (Optionally, one could skip the first step, and query
In summary, Win32USBControllerDevice Dependents are a complete list of USB Devices on a system (other than the Controllers themselves, which are the Antecedents in that same query), and by cross-referencing these PNPDeviceId pairs with information from the registry and from the other queries mentioned, a detailed picture can be constructed.
Border Height on CSS
.main-box{
border: solid 10px;
}
.sub-box{
border-right: 1px solid;
}
//draws a line on right side of the box. later add a margin-top and margin-bottom. i.e.,
.sub-box{
border-right: 1px solid;
margin-top: 10px;;
margin-bottom: 10px;
}
This might help in drawing a line on the right-side of the box with a gap on top and bottom.
Proper use of mutexes in Python
I would like to improve answer from chris-b a little bit more.
See below for my code:
from threading import Thread, Lock
import threading
mutex = Lock()
def processData(data, thread_safe):
if thread_safe:
mutex.acquire()
try:
thread_id = threading.get_ident()
print('\nProcessing data:', data, "ThreadId:", thread_id)
finally:
if thread_safe:
mutex.release()
counter = 0
max_run = 100
thread_safe = False
while True:
some_data = counter
t = Thread(target=processData, args=(some_data, thread_safe))
t.start()
counter = counter + 1
if counter >= max_run:
break
In your first run if you set thread_safe = False in while loop, mutex will not be used, and threads will step over each others in print method as below;
but, if you set thread_safe = True and run it, you will see all the output comes perfectly fine;
hope this helps.
Getting Integer value from a String using javascript/jquery
str1 = "test123.00";
str2 = "yes50.00";
intStr1 = str1.replace(/[A-Za-z$-]/g, "");
intStr2 = str2.replace(/[A-Za-z$-]/g, "");
total = parseInt(intStr1)+parseInt(intStr2);
alert(total);
working Jsfiddle
Running a command as Administrator using PowerShell?
If the current console is not elevated and the operation you're trying to do requires elevated privileges then you can start powershell with the Run as Administrator option :
PS> Start-Process powershell -Verb runAs
https://docs.microsoft.com/powershell/module/Microsoft.PowerShell.Management/Start-Process
Are vectors passed to functions by value or by reference in C++
void foo(vector<int> test)
vector would be passed by value in this.
You have more ways to pass vectors depending on the context:-
1) Pass by reference:- This will let function foo change your contents of the vector. More efficient than pass by value as copying of vector is avoided.
2) Pass by const-reference:- This is efficient as well as reliable when you don't want function to change the contents of the vector.
What is the maximum possible length of a query string?
Different web stacks do support different lengths of http-requests. I know from experience that the early stacks of Safari only supported 4000 characters and thus had difficulty handling ASP.net pages because of the USER-STATE. This is even for POST, so you would have to check the browser and see what the stack limit is. I think that you may reach a limit even on newer browsers. I cannot remember but one of them (IE6, I think) had a limit of 16-bit limit, 32,768 or something.
alert() not working in Chrome
Take a look at this thread: http://code.google.com/p/chromium/issues/detail?id=4158
The problem is caused by javascript method "window.open(URL, windowName[, windowFeatures])". If the 3rd parameter windowFeatures is specified, then alert box doesn't work in the popup constrained window in Chrome, here is a simplified reduction:
http://go/reductions/4158/test-home-constrained.html
If the 3rd parameter windowFeatures is ignored, then alert box works in the popup in Chrome(the popup is actually opened as a new tab in Chrome), like this:
http://go/reductions/4158/test-home-newtab.html
it doesn't happen in IE7, Firefox3 or Safari3, it's a chrome specific issue.
See also attachments for simplified reductions
How to find the socket connection state in C?
For BSD sockets I'd check out Beej's guide. When recv returns 0 you know the other side disconnected.
Now you might actually be asking, what is the easiest way to detect the other side disconnecting? One way of doing it is to have a thread always doing a recv. That thread will be able to instantly tell when the client disconnects.
Regex - Does not contain certain Characters
^[^<>]+$
The caret in the character class ([^) means match anything but, so this means, beginning of string, then one or more of anything except < and >, then the end of the string.
How to make a JSONP request from Javascript without JQuery?
the way I use jsonp like below:
function jsonp(uri) {
return new Promise(function(resolve, reject) {
var id = '_' + Math.round(10000 * Math.random());
var callbackName = 'jsonp_callback_' + id;
window[callbackName] = function(data) {
delete window[callbackName];
var ele = document.getElementById(id);
ele.parentNode.removeChild(ele);
resolve(data);
}
var src = uri + '&callback=' + callbackName;
var script = document.createElement('script');
script.src = src;
script.id = id;
script.addEventListener('error', reject);
(document.getElementsByTagName('head')[0] || document.body || document.documentElement).appendChild(script)
});
}
then use 'jsonp' method like this:
jsonp('http://xxx/cors').then(function(data){
console.log(data);
});
reference:
JavaScript XMLHttpRequest using JsonP
http://www.w3ctech.com/topic/721 (talk about the way of use Promise)
Program does not contain a static 'Main' method suitable for an entry point
Check the properties of App.xaml. Is the Build Action still ApplicationDefinition?
What does "Object reference not set to an instance of an object" mean?
If I have the class:
public class MyClass
{
public void MyMethod()
{
}
}
and I then do:
MyClass myClass = null;
myClass.MyMethod();
The second line throws this exception becuase I'm calling a method on a reference type object that is null (I.e. has not been instantiated by calling myClass = new MyClass())
If you can decode JWT, how are they secure?
I would suggest in taking a look into JWE using special algorithms which is not present in jwt.io to decrypt
Reference link: https://www.npmjs.com/package/node-webtokens
jwt.generate('PBES2-HS512+A256KW', 'A256GCM', payload, pwd, (error, token) => {
jwt.parse(token).verify(pwd, (error, parsedToken) => {
// other statements
});
});
This answer may be too late or you might have already found out the way, but still, I felt it would be helpful for you and others as well.
A simple example which I have created: https://github.com/hansiemithun/jwe-example
How do you uninstall the package manager "pip", if installed from source?
pip uninstall pip will work
Strings in C, how to get subString
You can treat C strings like pointers. So when you declare:
char str[10];
str can be used as a pointer. So if you want to copy just a portion of the string you can use:
char str1[24] = "This is a simple string.";
char str2[6];
strncpy(str1 + 10, str2,6);
This will copy 6 characters from the str1 array into str2 starting at the 11th element.
In Python script, how do I set PYTHONPATH?
I linux this works too:
import sys
sys.path.extend(["/path/to/dotpy/file/"])
How do I delete everything below row X in VBA/Excel?
This function will clear the sheet data starting from specified row and column :
Sub ClearWKSData(wksCur As Worksheet, iFirstRow As Integer, iFirstCol As Integer)
Dim iUsedCols As Integer
Dim iUsedRows As Integer
iUsedRows = wksCur.UsedRange.Row + wksCur.UsedRange.Rows.Count - 1
iUsedCols = wksCur.UsedRange.Column + wksCur.UsedRange.Columns.Count - 1
If iUsedRows > iFirstRow And iUsedCols > iFirstCol Then
wksCur.Range(wksCur.Cells(iFirstRow, iFirstCol), wksCur.Cells(iUsedRows, iUsedCols)).Clear
End If
End Sub
ValueError: invalid literal for int () with base 10
I had hard time figuring out the actual reason, it happens when we dont read properly from file. you need to open file and read with readlines() method as below:
with open('/content/drive/pre-processed-users1.1.tsv') as f:
file=f.readlines()
It corrects the formatted output
Check if pull needed in Git
git ls-remote | cut -f1 | git cat-file --batch-check >&-
will list everything referenced in any remote that isn't in your repo. To catch remote ref changes to things you already had (e.g. resets to previous commits) takes a little more:
git pack-refs --all
mine=`mktemp`
sed '/^#/d;/^^/{G;s/.\(.*\)\n.* \(.*\)/\1 \2^{}/;};h' .git/packed-refs | sort -k2 >$mine
for r in `git remote`; do
echo Checking $r ...
git ls-remote $r | sort -k2 | diff -b - $mine | grep ^\<
done
How to create an Observable from static data similar to http one in Angular?
This is how you can create a simple observable for static data.
let observable = Observable.create(observer => {
setTimeout(() => {
let users = [
{username:"balwant.padwal",city:"pune"},
{username:"test",city:"mumbai"}]
observer.next(users); // This method same as resolve() method from Angular 1
console.log("am done");
observer.complete();//to show we are done with our processing
// observer.error(new Error("error message"));
}, 2000);
})
to subscribe to it is very easy
observable.subscribe((data)=>{
console.log(data); // users array display
});
I hope this answer is helpful. We can use HTTP call instead static data.
Compare and contrast REST and SOAP web services?
SOAP brings it’s own protocol and focuses on exposing pieces of application logic (not data) as services. SOAP exposes operations. SOAP is focused on accessing named operations, each implement some business logic through different interfaces.
Though SOAP is commonly referred to as “web services” this is a misnomer. SOAP has very little if anything to do with the Web. REST provides true “Web services” based on URIs and HTTP.
By way of illustration here are few calls and their appropriate home with commentary.
getUser(User);
This is a rest operation as you are accessing a resource (data).
switchCategory(User, OldCategory, NewCategory)
REST permits many different data formats where as SOAP only permits XML. While this may seem like it adds complexity to REST because you need to handle multiple formats, in my experience it has actually been quite beneficial. JSON usually is a better fit for data and parses much faster. REST allows better support for browser clients due to it’s support for JSON.
How to update a single library with Composer?
Difference between install, update and require
Assume the following scenario:
composer.json
"parsecsv/php-parsecsv": "0.*"
composer.lock file
"name": "parsecsv/php-parsecsv",
"version": "0.1.4",
Latest release is
1.1.0. The latest0.*release is0.3.2
install: composer install parsecsv/php-parsecsv
This will install version 0.1.4 as specified in the lock file
update: composer update parsecsv/php-parsecsv
This will update the package to 0.3.2. The highest version with respect to your composer.json. The entry in composer.lock will be updated.
require: composer require parsecsv/php-parsecsv
This will update or install the newest version 1.1.0. Your composer.lock file and composer.json file will be updated as well.
Repeat String - Javascript
Concatenating strings based on an number.
function concatStr(str, num) {
var arr = [];
//Construct an array
for (var i = 0; i < num; i++)
arr[i] = str;
//Join all elements
str = arr.join('');
return str;
}
console.log(concatStr("abc", 3));
Hope that helps!
Find the smallest positive integer that does not occur in a given sequence
This code has been writen in Java SE 8
import java.util.*;
public class Solution {
public int solution(int[] A) {
int smallestPositiveInt = 1;
if(A.length == 0) {
return smallestPositiveInt;
}
Arrays.sort(A);
if(A[0] > 1) {
return smallestPositiveInt;
}
if(A[A.length - 1] <= 0 ) {
return smallestPositiveInt;
}
for(int x = 0; x < A.length; x++) {
if(A[x] == smallestPositiveInt) {
smallestPositiveInt++;
}
}
return smallestPositiveInt;
}
}
FPDF error: Some data has already been output, can't send PDF
For fpdf to work properly, there cannot be any output at all beside what fpdf generates. For example, this will work:
<?php
$pdf = new FPDF();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
$pdf->Output();
?>
While this will not (note the leading space before the opening <? tag)
<?php
$pdf = new FPDF();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
$pdf->Output();
?>
Also, this will not work either (the echo will break it):
<?php
echo "About to create pdf";
$pdf = new FPDF();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
$pdf->Output();
?>
I'm not sure about the drupal side of things, but I know that absolutely zero non-fpdf output is a requirement for fpdf to work.
add ob_start (); at the top and at the end add ob_end_flush();
<?php
ob_start();
require('fpdf.php');
$pdf = new FPDF();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
$pdf->Output();
ob_end_flush();
?>
give me an error as below:
FPDF error: Some data has already been output, can't send PDF
to over come this error:
go to fpdf.php in that,goto line number 996
function Output($name='', $dest='')
after that make changes like this:
function Output($name='', $dest='') {
ob_clean(); //Output PDF to so
Hi do you have a session header on the top of your page. or any includes If you have then try to add this codes on top pf your page it should works fine.
<?
while (ob_get_level())
ob_end_clean();
header("Content-Encoding: None", true);
?>
cheers :-)
In my case i had set:
ini_set('display_errors', 'on');
error_reporting(E_ALL | E_STRICT);
When i made the request to generate the report, some warnings were displayed in the browser (like the usage of deprecated functions).
Turning off the display_errors option, the report was generated successfully.
Excel VBA: function to turn activecell to bold
I use
chartRange = xlWorkSheet.Rows[1];
chartRange.Font.Bold = true;
to turn the first-row-cells-font into bold. And it works, and I am using also Excel 2007.
You can call in VBA directly
ActiveCell.Font.Bold = True
With this code I create a timestamp in the active cell, with bold font and yellow background
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
ActiveCell.Value = Now()
ActiveCell.Font.Bold = True
ActiveCell.Interior.ColorIndex = 6
End Sub
sweet-alert display HTML code in text
Sweet alerts also has an 'html' option, set it to true.
var hh = "<b>test</b>";
swal({
title: "" + txt + "",
html: true,
text: "Testno sporocilo za objekt " + hh + "",
confirmButtonText: "V redu",
allowOutsideClick: "true"
});
Create a list with initial capacity in Python
As others have mentioned, the simplest way to preseed a list is with NoneType objects.
That being said, you should understand the way Python lists actually work before deciding this is necessary.
In the CPython implementation of a list, the underlying array is always created with overhead room, in progressively larger sizes ( 4, 8, 16, 25, 35, 46, 58, 72, 88, 106, 126, 148, 173, 201, 233, 269, 309, 354, 405, 462, 526, 598, 679, 771, 874, 990, 1120, etc), so that resizing the list does not happen nearly so often.
Because of this behavior, most list.append() functions are O(1) complexity for appends, only having increased complexity when crossing one of these boundaries, at which point the complexity will be O(n). This behavior is what leads to the minimal increase in execution time in S.Lott's answer.
Source: Python list implementation
How do I apply a perspective transform to a UIView?
As Ben said, you'll need to work with the UIView's layer, using a CATransform3D to perform the layer's rotation. The trick to get perspective working, as described here, is to directly access one of the matrix cells of the CATransform3D (m34). Matrix math has never been my thing, so I can't explain exactly why this works, but it does. You'll need to set this value to a negative fraction for your initial transform, then apply your layer rotation transforms to that. You should also be able to do the following:
Objective-C
UIView *myView = [[self subviews] objectAtIndex:0];
CALayer *layer = myView.layer;
CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;
rotationAndPerspectiveTransform.m34 = 1.0 / -500;
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, 45.0f * M_PI / 180.0f, 0.0f, 1.0f, 0.0f);
layer.transform = rotationAndPerspectiveTransform;
Swift 5.0
if let myView = self.subviews.first {
let layer = myView.layer
var rotationAndPerspectiveTransform = CATransform3DIdentity
rotationAndPerspectiveTransform.m34 = 1.0 / -500
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, 45.0 * .pi / 180.0, 0.0, 1.0, 0.0)
layer.transform = rotationAndPerspectiveTransform
}
which rebuilds the layer transform from scratch for each rotation.
A full example of this (with code) can be found here, where I've implemented touch-based rotation and scaling on a couple of CALayers, based on an example by Bill Dudney. The newest version of the program, at the very bottom of the page, implements this kind of perspective operation. The code should be reasonably simple to read.
The sublayerTransform you refer to in your response is a transform that is applied to the sublayers of your UIView's CALayer. If you don't have any sublayers, don't worry about it. I use the sublayerTransform in my example simply because there are two CALayers contained within the one layer that I'm rotating.
How to run crontab job every week on Sunday
Cron job expression in a human-readable way crontab builder
How do I get TimeSpan in minutes given two Dates?
Why not just doing it this way?
DateTime dt1 = new DateTime(2009, 6, 1);
DateTime dt2 = DateTime.Now;
double totalminutes = (dt2 - dt1).TotalMinutes;
Hope this helps.
Apply Calibri (Body) font to text
There is no such font as “Calibri (Body)”. You probably saw this string in Microsoft Word font selection menu, but it’s not a font name (see e.g. the explanation Font: +body (in W07)).
So use just font-family: Calibri or, better, font-family: Calibri, sans-serif. (There is no adequate backup font for Calibri, but the odds are that when Calibri is not available, the browser’s default sans-serif font suits your design better than the browser’s default font, which is most often a serif font.)
How to Call a Function inside a Render in React/Jsx
To call the function you have to add ()
{this.renderIcon()}
Find JavaScript function definition in Chrome
Lets say we're looking for function named foo:
- (open Chrome dev-tools),
- Windows: ctrl + shift + F, or macOS: cmd + optn + F. This opens a window for searching across all scripts.
- check "Regular expression" checkbox,
- search for
foo\s*=\s*function(searches forfoo = functionwith any number of spaces between those three tokens), - press on a returned result.
Another variant for function definition is function\s*foo\s*\( for function foo( with any number of spaces between those three tokens.
Rotate and translate
Something that may get missed: in my chaining project, it turns out a space separated list also needs a space separated semicolon at the end.
In other words, this doesn't work:
transform: translate(50%, 50%) rotate(90deg);
but this does:
transform: translate(50%, 50%) rotate(90deg) ; //has a space before ";"
How can you get the build/version number of your Android application?
Slightly shorter version if you just want the version name.
String versionName = context.getPackageManager()
.getPackageInfo(context.getPackageName(), 0).versionName;
How to replace text of a cell based on condition in excel
You can use the Conditional Formatting to replace text and NOT effect any formulas. Simply go to the Rule's format where you will see Number, Font, Border and Fill.
Go to the Number tab and select CUSTOM. Then simply type where it says TYPE: what you want to say in QUOTES.
Example.. "OTHER"
How to find the 'sizeof' (a pointer pointing to an array)?
The answer is, "No."
What C programmers do is store the size of the array somewhere. It can be part of a structure, or the programmer can cheat a bit and malloc() more memory than requested in order to store a length value before the start of the array.
Validation for 10 digit mobile number and focus input field on invalid
After testing all answers without success. Some times input take alpha character also.
Here is the last full working code with only numbers input also keeping in mind backspace button key event for user if something number is incorrect.
$("#phone").keydown(function(event) {_x000D_
k = event.which;_x000D_
if ((k >= 96 && k <= 105) || k == 8) {_x000D_
if ($(this).val().length == 10) {_x000D_
if (k == 8) {_x000D_
return true;_x000D_
} else {_x000D_
event.preventDefault();_x000D_
return false;_x000D_
_x000D_
}_x000D_
}_x000D_
} else {_x000D_
event.preventDefault();_x000D_
return false;_x000D_
}_x000D_
_x000D_
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input name="phone" id="phone" placeholder="Mobile Number" class="form-control" type="number" required>What exactly is the 'react-scripts start' command?
create-react-app and react-scripts
react-scripts is a set of scripts from the create-react-app starter pack. create-react-app helps you kick off projects without configuring, so you do not have to setup your project by yourself.
react-scripts start sets up the development environment and starts a server, as well as hot module reloading. You can read here to see what everything it does for you.
with create-react-app you have following features out of the box.
- React, JSX, ES6, and Flow syntax support.
- Language extras beyond ES6 like the object spread operator.
- Autoprefixed CSS, so you don’t need -webkit- or other prefixes.
- A fast interactive unit test runner with built-in support for coverage reporting.
- A live development server that warns about common mistakes.
- A build script to bundle JS, CSS, and images for production, with hashes and sourcemaps.
- An offline-first service worker and a web app manifest, meeting all the Progressive Web App criteria.
- Hassle-free updates for the above tools with a single dependency.
npm scripts
npm start is a shortcut for npm run start.
npm run is used to run scripts that you define in the scripts object of your package.json
if there is no start key in the scripts object, it will default to node server.js
Sometimes you want to do more than the react scripts gives you, in this case you can do react-scripts eject. This will transform your project from a "managed" state into a not managed state, where you have full control over dependencies, build scripts and other configurations.
How do I request a file but not save it with Wget?
Curl does that by default without any parameters or flags, I would use it for your purposes:
curl $url > /dev/null 2>&1
Curl is more about streams and wget is more about copying sites based on this comparison.
Getting XML Node text value with Java DOM
If your XML goes quite deep, you might want to consider using XPath, which comes with your JRE, so you can access the contents far more easily using:
String text = xp.evaluate("//add[@job='351']/tag[position()=1]/text()",
document.getDocumentElement());
Full example:
import static org.junit.Assert.assertEquals;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathFactory;
import org.junit.Before;
import org.junit.Test;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
public class XPathTest {
private Document document;
@Before
public void setup() throws Exception {
String xml = "<add job=\"351\"><tag>foobar</tag><tag>foobar2</tag></add>";
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
document = db.parse(new InputSource(new StringReader(xml)));
}
@Test
public void testXPath() throws Exception {
XPathFactory xpf = XPathFactory.newInstance();
XPath xp = xpf.newXPath();
String text = xp.evaluate("//add[@job='351']/tag[position()=1]/text()",
document.getDocumentElement());
assertEquals("foobar", text);
}
}
Add an index (numeric ID) column to large data frame
If your data.frame is a data.table, you can use special symbol .I:
data[, ID := .I]
Why is “while ( !feof (file) )” always wrong?
feof() indicates if one has tried to read past the end of file. That means it has little predictive effect: if it is true, you are sure that the next input operation will fail (you aren't sure the previous one failed BTW), but if it is false, you aren't sure the next input operation will succeed. More over, input operations may fail for other reasons than the end of file (a format error for formatted input, a pure IO failure -- disk failure, network timeout -- for all input kinds), so even if you could be predictive about the end of file (and anybody who has tried to implement Ada one, which is predictive, will tell you it can complex if you need to skip spaces, and that it has undesirable effects on interactive devices -- sometimes forcing the input of the next line before starting the handling of the previous one), you would have to be able to handle a failure.
So the correct idiom in C is to loop with the IO operation success as loop condition, and then test the cause of the failure. For instance:
while (fgets(line, sizeof(line), file)) {
/* note that fgets don't strip the terminating \n, checking its
presence allow to handle lines longer that sizeof(line), not showed here */
...
}
if (ferror(file)) {
/* IO failure */
} else if (feof(file)) {
/* format error (not possible with fgets, but would be with fscanf) or end of file */
} else {
/* format error (not possible with fgets, but would be with fscanf) */
}
How to get a path to the desktop for current user in C#?
// Environment.GetFolderPath
Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData); // Current User's Application Data
Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData); // All User's Application Data
Environment.GetFolderPath(Environment.SpecialFolder.CommonProgramFiles); // Program Files
Environment.GetFolderPath(Environment.SpecialFolder.Cookies); // Internet Cookie
Environment.GetFolderPath(Environment.SpecialFolder.Desktop); // Logical Desktop
Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory); // Physical Desktop
Environment.GetFolderPath(Environment.SpecialFolder.Favorites); // Favorites
Environment.GetFolderPath(Environment.SpecialFolder.History); // Internet History
Environment.GetFolderPath(Environment.SpecialFolder.InternetCache); // Internet Cache
Environment.GetFolderPath(Environment.SpecialFolder.MyComputer); // "My Computer" Folder
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); // "My Documents" Folder
Environment.GetFolderPath(Environment.SpecialFolder.MyMusic); // "My Music" Folder
Environment.GetFolderPath(Environment.SpecialFolder.MyPictures); // "My Pictures" Folder
Environment.GetFolderPath(Environment.SpecialFolder.Personal); // "My Document" Folder
Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles); // Program files Folder
Environment.GetFolderPath(Environment.SpecialFolder.Programs); // Programs Folder
Environment.GetFolderPath(Environment.SpecialFolder.Recent); // Recent Folder
Environment.GetFolderPath(Environment.SpecialFolder.SendTo); // "Sent to" Folder
Environment.GetFolderPath(Environment.SpecialFolder.StartMenu); // Start Menu
Environment.GetFolderPath(Environment.SpecialFolder.Startup); // Startup
Environment.GetFolderPath(Environment.SpecialFolder.System); // System Folder
Environment.GetFolderPath(Environment.SpecialFolder.Templates); // Document Templates
Getting the PublicKeyToken of .Net assemblies
If you have included the assembly in your project, you can do :
var assemblies =
AppDomain.CurrentDomain.GetAssemblies();
foreach (var assem in assemblies)
{
Console.WriteLine(assem.FullName);
}
Warning as error - How to get rid of these
The top answer is outdated for Visual Studio 2015.
English:
Configuration Properties -> C/C++ -> General -> Treat Warning As Errors
German:
Konfigurationseigenschaften -> C/C++ -> Allgemein -> Warnungen als Fehler behandeln
Or use this image as reference, way easier to quickly mentally figure out the location:
How to SHUTDOWN Tomcat in Ubuntu?
If you installed tomcat manually, run the shutdown.sh(/.../tomcat/bin) from the terminal to shut it down easily.
ImportError in importing from sklearn: cannot import name check_build
My solution for Python 3.6.5 64-bit Windows 10:
pip uninstall sklearnpip uninstall scikit-learnpip install sklearn
No need to restart command-line but you can do this if you want. It took me one day to fix this bug. Hope this help.
How to serve all existing static files directly with NGINX, but proxy the rest to a backend server.
Try this:
location / {
root /path/to/root;
expires 30d;
access_log off;
}
location ~* ^.*\.php$ {
if (!-f $request_filename) {
return 404;
}
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://127.0.0.1:8080;
}
Hopefully it works. Regular expressions have higher priority than plain strings, so all requests ending in .php should be forwared to Apache if only a corresponding .php file exists. Rest will be handled as static files. The actual algorithm of evaluating location is here.
How to change a single value in a NumPy array?
Is this what you are after? Just index the element and assign a new value.
A[2,1]=150
A
Out[345]:
array([[ 1, 2, 3, 4],
[ 5, 6, 7, 8],
[ 9, 150, 11, 12],
[13, 14, 15, 16]])
Unfortunately Launcher3 has stopped working error in android studio?
I didn't found any particular answer to this question but i deleted the emulator and create a new one and increase the Ram size of the new emulator.Then the emulator works fine.
How to call Stored Procedure in Entity Framework 6 (Code-First)?
You are using MapToStoredProcedures() which indicates that you are mapping your entities to stored procedures, when doing this you need to let go of the fact that there is a stored procedure and use the context as normal.
Something like this (written into the browser so not tested)
using(MyContext context = new MyContext())
{
Department department = new Department()
{
Name = txtDepartment.text.trim()
};
context.Set<Department>().Add(department);
}
If all you really trying to do is call a stored procedure directly then use SqlQuery
How to import large sql file in phpmyadmin
Best way to upload a large file not use phpmyadmin . cause phpmyadin at first upload the file using php upload class then execute sql that cause most of the time its time out happened.
best way is : enter wamp folder>bin>mysql>bin dirrectory then write this line
mysql -u root -p listnames < latestdb.sql here listnames is the database name at first please create the empty database and the latestdb.sql is your sql file name where your data present .
but one important thing is if your database file has unicode data . you must need to open your latestdb.sql file and one line before any line . the line is :
SET NAMES utf8; then your command mode run this script code
Select a row from html table and send values onclick of a button
In my case $(document).ready(function() was missing. Try this.
$(document).ready(function(){
("#table tr").click(function(){
$(this).addClass('selected').siblings().removeClass('selected');
var value=$(this).find('td:first').html();
alert(value);
});
$('.ok').on('click', function(e){
alert($("#table tr.selected td:first").html());
});
});
Using GroupBy, Count and Sum in LINQ Lambda Expressions
var q = from b in listOfBoxes
group b by b.Owner into g
select new
{
Owner = g.Key,
Boxes = g.Count(),
TotalWeight = g.Sum(item => item.Weight),
TotalVolume = g.Sum(item => item.Volume)
};
How to get hex color value rather than RGB value?
color class taken from bootstrap color picker
// Color object
var Color = function(val) {
this.value = {
h: 1,
s: 1,
b: 1,
a: 1
};
this.setColor(val);
};
Color.prototype = {
constructor: Color,
//parse a string to HSB
setColor: function(val){
val = val.toLowerCase();
var that = this;
$.each( CPGlobal.stringParsers, function( i, parser ) {
var match = parser.re.exec( val ),
values = match && parser.parse( match ),
space = parser.space||'rgba';
if ( values ) {
if (space === 'hsla') {
that.value = CPGlobal.RGBtoHSB.apply(null, CPGlobal.HSLtoRGB.apply(null, values));
} else {
that.value = CPGlobal.RGBtoHSB.apply(null, values);
}
return false;
}
});
},
setHue: function(h) {
this.value.h = 1- h;
},
setSaturation: function(s) {
this.value.s = s;
},
setLightness: function(b) {
this.value.b = 1- b;
},
setAlpha: function(a) {
this.value.a = parseInt((1 - a)*100, 10)/100;
},
// HSBtoRGB from RaphaelJS
// https://github.com/DmitryBaranovskiy/raphael/
toRGB: function(h, s, b, a) {
if (!h) {
h = this.value.h;
s = this.value.s;
b = this.value.b;
}
h *= 360;
var R, G, B, X, C;
h = (h % 360) / 60;
C = b * s;
X = C * (1 - Math.abs(h % 2 - 1));
R = G = B = b - C;
h = ~~h;
R += [C, X, 0, 0, X, C][h];
G += [X, C, C, X, 0, 0][h];
B += [0, 0, X, C, C, X][h];
return {
r: Math.round(R*255),
g: Math.round(G*255),
b: Math.round(B*255),
a: a||this.value.a
};
},
toHex: function(h, s, b, a){
var rgb = this.toRGB(h, s, b, a);
return '#'+((1 << 24) | (parseInt(rgb.r) << 16) | (parseInt(rgb.g) << 8) | parseInt(rgb.b)).toString(16).substr(1);
},
toHSL: function(h, s, b, a){
if (!h) {
h = this.value.h;
s = this.value.s;
b = this.value.b;
}
var H = h,
L = (2 - s) * b,
S = s * b;
if (L > 0 && L <= 1) {
S /= L;
} else {
S /= 2 - L;
}
L /= 2;
if (S > 1) {
S = 1;
}
return {
h: H,
s: S,
l: L,
a: a||this.value.a
};
}
};
how to use
var color = new Color("RGB(0,5,5)");
color.toHex()
Installed Java 7 on Mac OS X but Terminal is still using version 6
If you have Homebrew installed, you can install java-switcher to change Java default version more quickly
brew tap andycillin/tap
brew install java-switcher
Then you can use just one command to switch your default Java version.
java-switcher 1.7
or
java-switcher 10
jsPDF multi page PDF with HTML renderer
I have the same working issue. Searching in MrRio github I found this: https://github.com/MrRio/jsPDF/issues/101
Basically, you have to check the actual page size always before adding new content
doc = new jsPdf();
...
pageHeight= doc.internal.pageSize.height;
// Before adding new content
y = 500 // Height position of new content
if (y >= pageHeight)
{
doc.addPage();
y = 0 // Restart height position
}
doc.text(x, y, "value");
Sending HTTP POST Request In Java
I recomend use http-request built on apache http api.
HttpRequest<String> httpRequest = HttpRequestBuilder.createPost("http://www.example.com/page.php", String.class)
.responseDeserializer(ResponseDeserializer.ignorableDeserializer()).build();
public void send(){
String response = httpRequest.execute("id", "10").get();
}
ListView item background via custom selector
Never ever use a "background color" for your listview rows...
this will block every selector action (was my problem!)
good luck!
Python 3 TypeError: must be str, not bytes with sys.stdout.write()
While the accepted answer will work fine if the bytes you have from your subprocess are encoded using sys.stdout.encoding (or a compatible encoding, like reading from a tool that outputs ASCII and your stdout uses UTF-8), the correct way to write arbitrary bytes to stdout is:
sys.stdout.buffer.write(some_bytes_object)
This will just output the bytes as-is, without trying to treat them as text-in-some-encoding.
Android WebView progress bar
For a horizontal progress bar, you first need to define your progress bar and link it with your XML file like this, in the onCreate:
final TextView txtview = (TextView)findViewById(R.id.tV1);
final ProgressBar pbar = (ProgressBar) findViewById(R.id.pB1);
Then, you may use onProgressChanged Method in your WebChromeClient:
MyView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress) {
if(progress < 100 && pbar.getVisibility() == ProgressBar.GONE){
pbar.setVisibility(ProgressBar.VISIBLE);
txtview.setVisibility(View.VISIBLE);
}
pbar.setProgress(progress);
if(progress == 100) {
pbar.setVisibility(ProgressBar.GONE);
txtview.setVisibility(View.GONE);
}
}
});
After that, in your layout you have something like this
<TextView android:text="Loading, . . ."
android:textAppearance="?android:attr/textAppearanceSmall"
android:id="@+id/tV1" android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:textColor="#000000"></TextView>
<ProgressBar android:id="@+id/pB1"
style="?android:attr/progressBarStyleHorizontal" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:layout_centerVertical="true"
android:padding="2dip">
</ProgressBar>
This is how I did it in my app.
Why does foo = filter(...) return a <filter object>, not a list?
the reason why it returns < filter object > is that, filter is class instead of built-in function.
help(filter) you will get following:
Help on class filter in module builtins:
class filter(object)
| filter(function or None, iterable) --> filter object
|
| Return an iterator yielding those items of iterable for which function(item)
| is true. If function is None, return the items that are true.
|
| Methods defined here:
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __iter__(self, /)
| Implement iter(self).
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __next__(self, /)
| Implement next(self).
|
| __reduce__(...)
| Return state information for pickling.
How to use an arraylist as a prepared statement parameter
why making life hard-
PreparedStatement pstmt = conn.prepareStatement("select * from employee where id in ("+ StringUtils.join(arraylistParameter.iterator(),",") +)");
Importing images from a directory (Python) to list or dictionary
from PIL import Image
import os, os.path
imgs = []
path = "/home/tony/pictures"
valid_images = [".jpg",".gif",".png",".tga"]
for f in os.listdir(path):
ext = os.path.splitext(f)[1]
if ext.lower() not in valid_images:
continue
imgs.append(Image.open(os.path.join(path,f)))
Get the date (a day before current time) in Bash
Not very sexy but might do the job:
perl -e 'my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time - 86400);$year += 1900; $mon+= 1; printf ("YESTERDAY: %04d%02d%02d \n", $year, $mon, $mday)'
Formated from "martin clayton" answer.
How to add http:// if it doesn't exist in the URL
<?php
if (!preg_match("/^(http|ftp):/", $_POST['url'])) {
$_POST['url'] = 'http://'.$_POST['url'];
}
$url = $_POST['url'];
?>
This code will add http:// to the URL if it’s not there.
Unable to open project... cannot be opened because the project file cannot be parsed
It sounds like you're going to have to create a new project in Xcode, go into the old directory, and drag all your source files, nibs, and resources into the Xcode files sidebar in the new project. It shouldn't take more than a few minutes, unless you really did a lot of work with custom build settings or targets. Either that, or revert to the last check-in in your source control and manually add any code files which changed between now and then.
What is the email subject length limit?
RFC2322 states that the subject header "has no length restriction"
but to produce long headers but you need to split it across multiple lines, a process called "folding".
subject is defined as "unstructured" in RFC 5322
here's some quotes ([...] indicate stuff i omitted)
3.6.5. Informational Fields
The informational fields are all optional. The "Subject:" and
"Comments:" fields are unstructured fields as defined in section
2.2.1, [...]
2.2.1. Unstructured Header Field Bodies
Some field bodies in this specification are defined simply as
"unstructured" (which is specified in section 3.2.5 as any printable
US-ASCII characters plus white space characters) with no further
restrictions. These are referred to as unstructured field bodies.
Semantically, unstructured field bodies are simply to be treated as a
single line of characters with no further processing (except for
"folding" and "unfolding" as described in section 2.2.3).
2.2.3 [...] An unfolded header field has no length restriction and
therefore may be indeterminately long.